1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
4  * Written by Alex Tomas <alex@clusterfs.com>
5  */
6 
7 
8 /*
9  * mballoc.c contains the multiblocks allocation routines
10  */
11 
12 #include "ext4_jbd2.h"
13 #include "mballoc.h"
14 #include <linux/log2.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/nospec.h>
18 #include <linux/backing-dev.h>
19 #include <linux/freezer.h>
20 #include <trace/events/ext4.h>
21 
22 /*
23  * MUSTDO:
24  *   - test ext4_ext_search_left() and ext4_ext_search_right()
25  *   - search for metadata in few groups
26  *
27  * TODO v4:
28  *   - normalization should take into account whether file is still open
29  *   - discard preallocations if no free space left (policy?)
30  *   - don't normalize tails
31  *   - quota
32  *   - reservation for superuser
33  *
34  * TODO v3:
35  *   - bitmap read-ahead (proposed by Oleg Drokin aka green)
36  *   - track min/max extents in each group for better group selection
37  *   - mb_mark_used() may allocate chunk right after splitting buddy
38  *   - tree of groups sorted by number of free blocks
39  *   - error handling
40  */
41 
42 /*
43  * The allocation request involve request for multiple number of blocks
44  * near to the goal(block) value specified.
45  *
46  * During initialization phase of the allocator we decide to use the
47  * group preallocation or inode preallocation depending on the size of
48  * the file. The size of the file could be the resulting file size we
49  * would have after allocation, or the current file size, which ever
50  * is larger. If the size is less than sbi->s_mb_stream_request we
51  * select to use the group preallocation. The default value of
52  * s_mb_stream_request is 16 blocks. This can also be tuned via
53  * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
54  * terms of number of blocks.
55  *
56  * The main motivation for having small file use group preallocation is to
57  * ensure that we have small files closer together on the disk.
58  *
59  * First stage the allocator looks at the inode prealloc list,
60  * ext4_inode_info->i_prealloc_list, which contains list of prealloc
61  * spaces for this particular inode. The inode prealloc space is
62  * represented as:
63  *
64  * pa_lstart -> the logical start block for this prealloc space
65  * pa_pstart -> the physical start block for this prealloc space
66  * pa_len    -> length for this prealloc space (in clusters)
67  * pa_free   ->  free space available in this prealloc space (in clusters)
68  *
69  * The inode preallocation space is used looking at the _logical_ start
70  * block. If only the logical file block falls within the range of prealloc
71  * space we will consume the particular prealloc space. This makes sure that
72  * we have contiguous physical blocks representing the file blocks
73  *
74  * The important thing to be noted in case of inode prealloc space is that
75  * we don't modify the values associated to inode prealloc space except
76  * pa_free.
77  *
78  * If we are not able to find blocks in the inode prealloc space and if we
79  * have the group allocation flag set then we look at the locality group
80  * prealloc space. These are per CPU prealloc list represented as
81  *
82  * ext4_sb_info.s_locality_groups[smp_processor_id()]
83  *
84  * The reason for having a per cpu locality group is to reduce the contention
85  * between CPUs. It is possible to get scheduled at this point.
86  *
87  * The locality group prealloc space is used looking at whether we have
88  * enough free space (pa_free) within the prealloc space.
89  *
90  * If we can't allocate blocks via inode prealloc or/and locality group
91  * prealloc then we look at the buddy cache. The buddy cache is represented
92  * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
93  * mapped to the buddy and bitmap information regarding different
94  * groups. The buddy information is attached to buddy cache inode so that
95  * we can access them through the page cache. The information regarding
96  * each group is loaded via ext4_mb_load_buddy.  The information involve
97  * block bitmap and buddy information. The information are stored in the
98  * inode as:
99  *
100  *  {                        page                        }
101  *  [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
102  *
103  *
104  * one block each for bitmap and buddy information.  So for each group we
105  * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
106  * blocksize) blocks.  So it can have information regarding groups_per_page
107  * which is blocks_per_page/2
108  *
109  * The buddy cache inode is not stored on disk. The inode is thrown
110  * away when the filesystem is unmounted.
111  *
112  * We look for count number of blocks in the buddy cache. If we were able
113  * to locate that many free blocks we return with additional information
114  * regarding rest of the contiguous physical block available
115  *
116  * Before allocating blocks via buddy cache we normalize the request
117  * blocks. This ensure we ask for more blocks that we needed. The extra
118  * blocks that we get after allocation is added to the respective prealloc
119  * list. In case of inode preallocation we follow a list of heuristics
120  * based on file size. This can be found in ext4_mb_normalize_request. If
121  * we are doing a group prealloc we try to normalize the request to
122  * sbi->s_mb_group_prealloc.  The default value of s_mb_group_prealloc is
123  * dependent on the cluster size; for non-bigalloc file systems, it is
124  * 512 blocks. This can be tuned via
125  * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
126  * terms of number of blocks. If we have mounted the file system with -O
127  * stripe=<value> option the group prealloc request is normalized to the
128  * smallest multiple of the stripe value (sbi->s_stripe) which is
129  * greater than the default mb_group_prealloc.
130  *
131  * If "mb_optimize_scan" mount option is set, we maintain in memory group info
132  * structures in two data structures:
133  *
134  * 1) Array of largest free order lists (sbi->s_mb_largest_free_orders)
135  *
136  *    Locking: sbi->s_mb_largest_free_orders_locks(array of rw locks)
137  *
138  *    This is an array of lists where the index in the array represents the
139  *    largest free order in the buddy bitmap of the participating group infos of
140  *    that list. So, there are exactly MB_NUM_ORDERS(sb) (which means total
141  *    number of buddy bitmap orders possible) number of lists. Group-infos are
142  *    placed in appropriate lists.
143  *
144  * 2) Average fragment size lists (sbi->s_mb_avg_fragment_size)
145  *
146  *    Locking: sbi->s_mb_avg_fragment_size_locks(array of rw locks)
147  *
148  *    This is an array of lists where in the i-th list there are groups with
149  *    average fragment size >= 2^i and < 2^(i+1). The average fragment size
150  *    is computed as ext4_group_info->bb_free / ext4_group_info->bb_fragments.
151  *    Note that we don't bother with a special list for completely empty groups
152  *    so we only have MB_NUM_ORDERS(sb) lists.
153  *
154  * When "mb_optimize_scan" mount option is set, mballoc consults the above data
155  * structures to decide the order in which groups are to be traversed for
156  * fulfilling an allocation request.
157  *
158  * At CR_POWER2_ALIGNED , we look for groups which have the largest_free_order
159  * >= the order of the request. We directly look at the largest free order list
160  * in the data structure (1) above where largest_free_order = order of the
161  * request. If that list is empty, we look at remaining list in the increasing
162  * order of largest_free_order. This allows us to perform CR_POWER2_ALIGNED
163  * lookup in O(1) time.
164  *
165  * At CR_GOAL_LEN_FAST, we only consider groups where
166  * average fragment size > request size. So, we lookup a group which has average
167  * fragment size just above or equal to request size using our average fragment
168  * size group lists (data structure 2) in O(1) time.
169  *
170  * At CR_BEST_AVAIL_LEN, we aim to optimize allocations which can't be satisfied
171  * in CR_GOAL_LEN_FAST. The fact that we couldn't find a group in
172  * CR_GOAL_LEN_FAST suggests that there is no BG that has avg
173  * fragment size > goal length. So before falling to the slower
174  * CR_GOAL_LEN_SLOW, in CR_BEST_AVAIL_LEN we proactively trim goal length and
175  * then use the same fragment lists as CR_GOAL_LEN_FAST to find a BG with a big
176  * enough average fragment size. This increases the chances of finding a
177  * suitable block group in O(1) time and results in faster allocation at the
178  * cost of reduced size of allocation.
179  *
180  * If "mb_optimize_scan" mount option is not set, mballoc traverses groups in
181  * linear order which requires O(N) search time for each CR_POWER2_ALIGNED and
182  * CR_GOAL_LEN_FAST phase.
183  *
184  * The regular allocator (using the buddy cache) supports a few tunables.
185  *
186  * /sys/fs/ext4/<partition>/mb_min_to_scan
187  * /sys/fs/ext4/<partition>/mb_max_to_scan
188  * /sys/fs/ext4/<partition>/mb_order2_req
189  * /sys/fs/ext4/<partition>/mb_linear_limit
190  *
191  * The regular allocator uses buddy scan only if the request len is power of
192  * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
193  * value of s_mb_order2_reqs can be tuned via
194  * /sys/fs/ext4/<partition>/mb_order2_req.  If the request len is equal to
195  * stripe size (sbi->s_stripe), we try to search for contiguous block in
196  * stripe size. This should result in better allocation on RAID setups. If
197  * not, we search in the specific group using bitmap for best extents. The
198  * tunable min_to_scan and max_to_scan control the behaviour here.
199  * min_to_scan indicate how long the mballoc __must__ look for a best
200  * extent and max_to_scan indicates how long the mballoc __can__ look for a
201  * best extent in the found extents. Searching for the blocks starts with
202  * the group specified as the goal value in allocation context via
203  * ac_g_ex. Each group is first checked based on the criteria whether it
204  * can be used for allocation. ext4_mb_good_group explains how the groups are
205  * checked.
206  *
207  * When "mb_optimize_scan" is turned on, as mentioned above, the groups may not
208  * get traversed linearly. That may result in subsequent allocations being not
209  * close to each other. And so, the underlying device may get filled up in a
210  * non-linear fashion. While that may not matter on non-rotational devices, for
211  * rotational devices that may result in higher seek times. "mb_linear_limit"
212  * tells mballoc how many groups mballoc should search linearly before
213  * performing consulting above data structures for more efficient lookups. For
214  * non rotational devices, this value defaults to 0 and for rotational devices
215  * this is set to MB_DEFAULT_LINEAR_LIMIT.
216  *
217  * Both the prealloc space are getting populated as above. So for the first
218  * request we will hit the buddy cache which will result in this prealloc
219  * space getting filled. The prealloc space is then later used for the
220  * subsequent request.
221  */
222 
223 /*
224  * mballoc operates on the following data:
225  *  - on-disk bitmap
226  *  - in-core buddy (actually includes buddy and bitmap)
227  *  - preallocation descriptors (PAs)
228  *
229  * there are two types of preallocations:
230  *  - inode
231  *    assiged to specific inode and can be used for this inode only.
232  *    it describes part of inode's space preallocated to specific
233  *    physical blocks. any block from that preallocated can be used
234  *    independent. the descriptor just tracks number of blocks left
235  *    unused. so, before taking some block from descriptor, one must
236  *    make sure corresponded logical block isn't allocated yet. this
237  *    also means that freeing any block within descriptor's range
238  *    must discard all preallocated blocks.
239  *  - locality group
240  *    assigned to specific locality group which does not translate to
241  *    permanent set of inodes: inode can join and leave group. space
242  *    from this type of preallocation can be used for any inode. thus
243  *    it's consumed from the beginning to the end.
244  *
245  * relation between them can be expressed as:
246  *    in-core buddy = on-disk bitmap + preallocation descriptors
247  *
248  * this mean blocks mballoc considers used are:
249  *  - allocated blocks (persistent)
250  *  - preallocated blocks (non-persistent)
251  *
252  * consistency in mballoc world means that at any time a block is either
253  * free or used in ALL structures. notice: "any time" should not be read
254  * literally -- time is discrete and delimited by locks.
255  *
256  *  to keep it simple, we don't use block numbers, instead we count number of
257  *  blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
258  *
259  * all operations can be expressed as:
260  *  - init buddy:			buddy = on-disk + PAs
261  *  - new PA:				buddy += N; PA = N
262  *  - use inode PA:			on-disk += N; PA -= N
263  *  - discard inode PA			buddy -= on-disk - PA; PA = 0
264  *  - use locality group PA		on-disk += N; PA -= N
265  *  - discard locality group PA		buddy -= PA; PA = 0
266  *  note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
267  *        is used in real operation because we can't know actual used
268  *        bits from PA, only from on-disk bitmap
269  *
270  * if we follow this strict logic, then all operations above should be atomic.
271  * given some of them can block, we'd have to use something like semaphores
272  * killing performance on high-end SMP hardware. let's try to relax it using
273  * the following knowledge:
274  *  1) if buddy is referenced, it's already initialized
275  *  2) while block is used in buddy and the buddy is referenced,
276  *     nobody can re-allocate that block
277  *  3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
278  *     bit set and PA claims same block, it's OK. IOW, one can set bit in
279  *     on-disk bitmap if buddy has same bit set or/and PA covers corresponded
280  *     block
281  *
282  * so, now we're building a concurrency table:
283  *  - init buddy vs.
284  *    - new PA
285  *      blocks for PA are allocated in the buddy, buddy must be referenced
286  *      until PA is linked to allocation group to avoid concurrent buddy init
287  *    - use inode PA
288  *      we need to make sure that either on-disk bitmap or PA has uptodate data
289  *      given (3) we care that PA-=N operation doesn't interfere with init
290  *    - discard inode PA
291  *      the simplest way would be to have buddy initialized by the discard
292  *    - use locality group PA
293  *      again PA-=N must be serialized with init
294  *    - discard locality group PA
295  *      the simplest way would be to have buddy initialized by the discard
296  *  - new PA vs.
297  *    - use inode PA
298  *      i_data_sem serializes them
299  *    - discard inode PA
300  *      discard process must wait until PA isn't used by another process
301  *    - use locality group PA
302  *      some mutex should serialize them
303  *    - discard locality group PA
304  *      discard process must wait until PA isn't used by another process
305  *  - use inode PA
306  *    - use inode PA
307  *      i_data_sem or another mutex should serializes them
308  *    - discard inode PA
309  *      discard process must wait until PA isn't used by another process
310  *    - use locality group PA
311  *      nothing wrong here -- they're different PAs covering different blocks
312  *    - discard locality group PA
313  *      discard process must wait until PA isn't used by another process
314  *
315  * now we're ready to make few consequences:
316  *  - PA is referenced and while it is no discard is possible
317  *  - PA is referenced until block isn't marked in on-disk bitmap
318  *  - PA changes only after on-disk bitmap
319  *  - discard must not compete with init. either init is done before
320  *    any discard or they're serialized somehow
321  *  - buddy init as sum of on-disk bitmap and PAs is done atomically
322  *
323  * a special case when we've used PA to emptiness. no need to modify buddy
324  * in this case, but we should care about concurrent init
325  *
326  */
327 
328  /*
329  * Logic in few words:
330  *
331  *  - allocation:
332  *    load group
333  *    find blocks
334  *    mark bits in on-disk bitmap
335  *    release group
336  *
337  *  - use preallocation:
338  *    find proper PA (per-inode or group)
339  *    load group
340  *    mark bits in on-disk bitmap
341  *    release group
342  *    release PA
343  *
344  *  - free:
345  *    load group
346  *    mark bits in on-disk bitmap
347  *    release group
348  *
349  *  - discard preallocations in group:
350  *    mark PAs deleted
351  *    move them onto local list
352  *    load on-disk bitmap
353  *    load group
354  *    remove PA from object (inode or locality group)
355  *    mark free blocks in-core
356  *
357  *  - discard inode's preallocations:
358  */
359 
360 /*
361  * Locking rules
362  *
363  * Locks:
364  *  - bitlock on a group	(group)
365  *  - object (inode/locality)	(object)
366  *  - per-pa lock		(pa)
367  *  - cr_power2_aligned lists lock	(cr_power2_aligned)
368  *  - cr_goal_len_fast lists lock	(cr_goal_len_fast)
369  *
370  * Paths:
371  *  - new pa
372  *    object
373  *    group
374  *
375  *  - find and use pa:
376  *    pa
377  *
378  *  - release consumed pa:
379  *    pa
380  *    group
381  *    object
382  *
383  *  - generate in-core bitmap:
384  *    group
385  *        pa
386  *
387  *  - discard all for given object (inode, locality group):
388  *    object
389  *        pa
390  *    group
391  *
392  *  - discard all for given group:
393  *    group
394  *        pa
395  *    group
396  *        object
397  *
398  *  - allocation path (ext4_mb_regular_allocator)
399  *    group
400  *    cr_power2_aligned/cr_goal_len_fast
401  */
402 static struct kmem_cache *ext4_pspace_cachep;
403 static struct kmem_cache *ext4_ac_cachep;
404 static struct kmem_cache *ext4_free_data_cachep;
405 
406 /* We create slab caches for groupinfo data structures based on the
407  * superblock block size.  There will be one per mounted filesystem for
408  * each unique s_blocksize_bits */
409 #define NR_GRPINFO_CACHES 8
410 static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
411 
412 static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
413 	"ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
414 	"ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
415 	"ext4_groupinfo_64k", "ext4_groupinfo_128k"
416 };
417 
418 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
419 					ext4_group_t group);
420 static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac);
421 
422 static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
423 			       ext4_group_t group, enum criteria cr);
424 
425 static int ext4_try_to_trim_range(struct super_block *sb,
426 		struct ext4_buddy *e4b, ext4_grpblk_t start,
427 		ext4_grpblk_t max, ext4_grpblk_t minblocks);
428 
429 /*
430  * The algorithm using this percpu seq counter goes below:
431  * 1. We sample the percpu discard_pa_seq counter before trying for block
432  *    allocation in ext4_mb_new_blocks().
433  * 2. We increment this percpu discard_pa_seq counter when we either allocate
434  *    or free these blocks i.e. while marking those blocks as used/free in
435  *    mb_mark_used()/mb_free_blocks().
436  * 3. We also increment this percpu seq counter when we successfully identify
437  *    that the bb_prealloc_list is not empty and hence proceed for discarding
438  *    of those PAs inside ext4_mb_discard_group_preallocations().
439  *
440  * Now to make sure that the regular fast path of block allocation is not
441  * affected, as a small optimization we only sample the percpu seq counter
442  * on that cpu. Only when the block allocation fails and when freed blocks
443  * found were 0, that is when we sample percpu seq counter for all cpus using
444  * below function ext4_get_discard_pa_seq_sum(). This happens after making
445  * sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty.
446  */
447 static DEFINE_PER_CPU(u64, discard_pa_seq);
ext4_get_discard_pa_seq_sum(void)448 static inline u64 ext4_get_discard_pa_seq_sum(void)
449 {
450 	int __cpu;
451 	u64 __seq = 0;
452 
453 	for_each_possible_cpu(__cpu)
454 		__seq += per_cpu(discard_pa_seq, __cpu);
455 	return __seq;
456 }
457 
mb_correct_addr_and_bit(int * bit,void * addr)458 static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
459 {
460 #if BITS_PER_LONG == 64
461 	*bit += ((unsigned long) addr & 7UL) << 3;
462 	addr = (void *) ((unsigned long) addr & ~7UL);
463 #elif BITS_PER_LONG == 32
464 	*bit += ((unsigned long) addr & 3UL) << 3;
465 	addr = (void *) ((unsigned long) addr & ~3UL);
466 #else
467 #error "how many bits you are?!"
468 #endif
469 	return addr;
470 }
471 
mb_test_bit(int bit,void * addr)472 static inline int mb_test_bit(int bit, void *addr)
473 {
474 	/*
475 	 * ext4_test_bit on architecture like powerpc
476 	 * needs unsigned long aligned address
477 	 */
478 	addr = mb_correct_addr_and_bit(&bit, addr);
479 	return ext4_test_bit(bit, addr);
480 }
481 
mb_set_bit(int bit,void * addr)482 static inline void mb_set_bit(int bit, void *addr)
483 {
484 	addr = mb_correct_addr_and_bit(&bit, addr);
485 	ext4_set_bit(bit, addr);
486 }
487 
mb_clear_bit(int bit,void * addr)488 static inline void mb_clear_bit(int bit, void *addr)
489 {
490 	addr = mb_correct_addr_and_bit(&bit, addr);
491 	ext4_clear_bit(bit, addr);
492 }
493 
mb_test_and_clear_bit(int bit,void * addr)494 static inline int mb_test_and_clear_bit(int bit, void *addr)
495 {
496 	addr = mb_correct_addr_and_bit(&bit, addr);
497 	return ext4_test_and_clear_bit(bit, addr);
498 }
499 
mb_find_next_zero_bit(void * addr,int max,int start)500 static inline int mb_find_next_zero_bit(void *addr, int max, int start)
501 {
502 	int fix = 0, ret, tmpmax;
503 	addr = mb_correct_addr_and_bit(&fix, addr);
504 	tmpmax = max + fix;
505 	start += fix;
506 
507 	ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
508 	if (ret > max)
509 		return max;
510 	return ret;
511 }
512 
mb_find_next_bit(void * addr,int max,int start)513 static inline int mb_find_next_bit(void *addr, int max, int start)
514 {
515 	int fix = 0, ret, tmpmax;
516 	addr = mb_correct_addr_and_bit(&fix, addr);
517 	tmpmax = max + fix;
518 	start += fix;
519 
520 	ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
521 	if (ret > max)
522 		return max;
523 	return ret;
524 }
525 
mb_find_buddy(struct ext4_buddy * e4b,int order,int * max)526 static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
527 {
528 	char *bb;
529 
530 	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
531 	BUG_ON(max == NULL);
532 
533 	if (order > e4b->bd_blkbits + 1) {
534 		*max = 0;
535 		return NULL;
536 	}
537 
538 	/* at order 0 we see each particular block */
539 	if (order == 0) {
540 		*max = 1 << (e4b->bd_blkbits + 3);
541 		return e4b->bd_bitmap;
542 	}
543 
544 	bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
545 	*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
546 
547 	return bb;
548 }
549 
550 #ifdef DOUBLE_CHECK
mb_free_blocks_double(struct inode * inode,struct ext4_buddy * e4b,int first,int count)551 static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
552 			   int first, int count)
553 {
554 	int i;
555 	struct super_block *sb = e4b->bd_sb;
556 
557 	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
558 		return;
559 	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
560 	for (i = 0; i < count; i++) {
561 		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
562 			ext4_fsblk_t blocknr;
563 
564 			blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
565 			blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
566 			ext4_grp_locked_error(sb, e4b->bd_group,
567 					      inode ? inode->i_ino : 0,
568 					      blocknr,
569 					      "freeing block already freed "
570 					      "(bit %u)",
571 					      first + i);
572 			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
573 					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
574 		}
575 		mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
576 	}
577 }
578 
mb_mark_used_double(struct ext4_buddy * e4b,int first,int count)579 static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
580 {
581 	int i;
582 
583 	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
584 		return;
585 	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
586 	for (i = 0; i < count; i++) {
587 		BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
588 		mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
589 	}
590 }
591 
mb_cmp_bitmaps(struct ext4_buddy * e4b,void * bitmap)592 static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
593 {
594 	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
595 		return;
596 	if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
597 		unsigned char *b1, *b2;
598 		int i;
599 		b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
600 		b2 = (unsigned char *) bitmap;
601 		for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
602 			if (b1[i] != b2[i]) {
603 				ext4_msg(e4b->bd_sb, KERN_ERR,
604 					 "corruption in group %u "
605 					 "at byte %u(%u): %x in copy != %x "
606 					 "on disk/prealloc",
607 					 e4b->bd_group, i, i * 8, b1[i], b2[i]);
608 				BUG();
609 			}
610 		}
611 	}
612 }
613 
mb_group_bb_bitmap_alloc(struct super_block * sb,struct ext4_group_info * grp,ext4_group_t group)614 static void mb_group_bb_bitmap_alloc(struct super_block *sb,
615 			struct ext4_group_info *grp, ext4_group_t group)
616 {
617 	struct buffer_head *bh;
618 
619 	grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
620 	if (!grp->bb_bitmap)
621 		return;
622 
623 	bh = ext4_read_block_bitmap(sb, group);
624 	if (IS_ERR_OR_NULL(bh)) {
625 		kfree(grp->bb_bitmap);
626 		grp->bb_bitmap = NULL;
627 		return;
628 	}
629 
630 	memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
631 	put_bh(bh);
632 }
633 
mb_group_bb_bitmap_free(struct ext4_group_info * grp)634 static void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
635 {
636 	kfree(grp->bb_bitmap);
637 }
638 
639 #else
mb_free_blocks_double(struct inode * inode,struct ext4_buddy * e4b,int first,int count)640 static inline void mb_free_blocks_double(struct inode *inode,
641 				struct ext4_buddy *e4b, int first, int count)
642 {
643 	return;
644 }
mb_mark_used_double(struct ext4_buddy * e4b,int first,int count)645 static inline void mb_mark_used_double(struct ext4_buddy *e4b,
646 						int first, int count)
647 {
648 	return;
649 }
mb_cmp_bitmaps(struct ext4_buddy * e4b,void * bitmap)650 static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
651 {
652 	return;
653 }
654 
mb_group_bb_bitmap_alloc(struct super_block * sb,struct ext4_group_info * grp,ext4_group_t group)655 static inline void mb_group_bb_bitmap_alloc(struct super_block *sb,
656 			struct ext4_group_info *grp, ext4_group_t group)
657 {
658 	return;
659 }
660 
mb_group_bb_bitmap_free(struct ext4_group_info * grp)661 static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
662 {
663 	return;
664 }
665 #endif
666 
667 #ifdef AGGRESSIVE_CHECK
668 
669 #define MB_CHECK_ASSERT(assert)						\
670 do {									\
671 	if (!(assert)) {						\
672 		printk(KERN_EMERG					\
673 			"Assertion failure in %s() at %s:%d: \"%s\"\n",	\
674 			function, file, line, # assert);		\
675 		BUG();							\
676 	}								\
677 } while (0)
678 
__mb_check_buddy(struct ext4_buddy * e4b,char * file,const char * function,int line)679 static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
680 				const char *function, int line)
681 {
682 	struct super_block *sb = e4b->bd_sb;
683 	int order = e4b->bd_blkbits + 1;
684 	int max;
685 	int max2;
686 	int i;
687 	int j;
688 	int k;
689 	int count;
690 	struct ext4_group_info *grp;
691 	int fragments = 0;
692 	int fstart;
693 	struct list_head *cur;
694 	void *buddy;
695 	void *buddy2;
696 
697 	if (e4b->bd_info->bb_check_counter++ % 10)
698 		return 0;
699 
700 	while (order > 1) {
701 		buddy = mb_find_buddy(e4b, order, &max);
702 		MB_CHECK_ASSERT(buddy);
703 		buddy2 = mb_find_buddy(e4b, order - 1, &max2);
704 		MB_CHECK_ASSERT(buddy2);
705 		MB_CHECK_ASSERT(buddy != buddy2);
706 		MB_CHECK_ASSERT(max * 2 == max2);
707 
708 		count = 0;
709 		for (i = 0; i < max; i++) {
710 
711 			if (mb_test_bit(i, buddy)) {
712 				/* only single bit in buddy2 may be 0 */
713 				if (!mb_test_bit(i << 1, buddy2)) {
714 					MB_CHECK_ASSERT(
715 						mb_test_bit((i<<1)+1, buddy2));
716 				}
717 				continue;
718 			}
719 
720 			/* both bits in buddy2 must be 1 */
721 			MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
722 			MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
723 
724 			for (j = 0; j < (1 << order); j++) {
725 				k = (i * (1 << order)) + j;
726 				MB_CHECK_ASSERT(
727 					!mb_test_bit(k, e4b->bd_bitmap));
728 			}
729 			count++;
730 		}
731 		MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
732 		order--;
733 	}
734 
735 	fstart = -1;
736 	buddy = mb_find_buddy(e4b, 0, &max);
737 	for (i = 0; i < max; i++) {
738 		if (!mb_test_bit(i, buddy)) {
739 			MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
740 			if (fstart == -1) {
741 				fragments++;
742 				fstart = i;
743 			}
744 			continue;
745 		}
746 		fstart = -1;
747 		/* check used bits only */
748 		for (j = 0; j < e4b->bd_blkbits + 1; j++) {
749 			buddy2 = mb_find_buddy(e4b, j, &max2);
750 			k = i >> j;
751 			MB_CHECK_ASSERT(k < max2);
752 			MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
753 		}
754 	}
755 	MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
756 	MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
757 
758 	grp = ext4_get_group_info(sb, e4b->bd_group);
759 	if (!grp)
760 		return NULL;
761 	list_for_each(cur, &grp->bb_prealloc_list) {
762 		ext4_group_t groupnr;
763 		struct ext4_prealloc_space *pa;
764 		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
765 		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
766 		MB_CHECK_ASSERT(groupnr == e4b->bd_group);
767 		for (i = 0; i < pa->pa_len; i++)
768 			MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
769 	}
770 	return 0;
771 }
772 #undef MB_CHECK_ASSERT
773 #define mb_check_buddy(e4b) __mb_check_buddy(e4b,	\
774 					__FILE__, __func__, __LINE__)
775 #else
776 #define mb_check_buddy(e4b)
777 #endif
778 
779 /*
780  * Divide blocks started from @first with length @len into
781  * smaller chunks with power of 2 blocks.
782  * Clear the bits in bitmap which the blocks of the chunk(s) covered,
783  * then increase bb_counters[] for corresponded chunk size.
784  */
ext4_mb_mark_free_simple(struct super_block * sb,void * buddy,ext4_grpblk_t first,ext4_grpblk_t len,struct ext4_group_info * grp)785 static void ext4_mb_mark_free_simple(struct super_block *sb,
786 				void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
787 					struct ext4_group_info *grp)
788 {
789 	struct ext4_sb_info *sbi = EXT4_SB(sb);
790 	ext4_grpblk_t min;
791 	ext4_grpblk_t max;
792 	ext4_grpblk_t chunk;
793 	unsigned int border;
794 
795 	BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
796 
797 	border = 2 << sb->s_blocksize_bits;
798 
799 	while (len > 0) {
800 		/* find how many blocks can be covered since this position */
801 		max = ffs(first | border) - 1;
802 
803 		/* find how many blocks of power 2 we need to mark */
804 		min = fls(len) - 1;
805 
806 		if (max < min)
807 			min = max;
808 		chunk = 1 << min;
809 
810 		/* mark multiblock chunks only */
811 		grp->bb_counters[min]++;
812 		if (min > 0)
813 			mb_clear_bit(first >> min,
814 				     buddy + sbi->s_mb_offsets[min]);
815 
816 		len -= chunk;
817 		first += chunk;
818 	}
819 }
820 
mb_avg_fragment_size_order(struct super_block * sb,ext4_grpblk_t len)821 static int mb_avg_fragment_size_order(struct super_block *sb, ext4_grpblk_t len)
822 {
823 	int order;
824 
825 	/*
826 	 * We don't bother with a special lists groups with only 1 block free
827 	 * extents and for completely empty groups.
828 	 */
829 	order = fls(len) - 2;
830 	if (order < 0)
831 		return 0;
832 	if (order == MB_NUM_ORDERS(sb))
833 		order--;
834 	return order;
835 }
836 
837 /* Move group to appropriate avg_fragment_size list */
838 static void
mb_update_avg_fragment_size(struct super_block * sb,struct ext4_group_info * grp)839 mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp)
840 {
841 	struct ext4_sb_info *sbi = EXT4_SB(sb);
842 	int new_order;
843 
844 	if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_fragments == 0)
845 		return;
846 
847 	new_order = mb_avg_fragment_size_order(sb,
848 					grp->bb_free / grp->bb_fragments);
849 	if (new_order == grp->bb_avg_fragment_size_order)
850 		return;
851 
852 	if (grp->bb_avg_fragment_size_order != -1) {
853 		write_lock(&sbi->s_mb_avg_fragment_size_locks[
854 					grp->bb_avg_fragment_size_order]);
855 		list_del(&grp->bb_avg_fragment_size_node);
856 		write_unlock(&sbi->s_mb_avg_fragment_size_locks[
857 					grp->bb_avg_fragment_size_order]);
858 	}
859 	grp->bb_avg_fragment_size_order = new_order;
860 	write_lock(&sbi->s_mb_avg_fragment_size_locks[
861 					grp->bb_avg_fragment_size_order]);
862 	list_add_tail(&grp->bb_avg_fragment_size_node,
863 		&sbi->s_mb_avg_fragment_size[grp->bb_avg_fragment_size_order]);
864 	write_unlock(&sbi->s_mb_avg_fragment_size_locks[
865 					grp->bb_avg_fragment_size_order]);
866 }
867 
868 /*
869  * Choose next group by traversing largest_free_order lists. Updates *new_cr if
870  * cr level needs an update.
871  */
ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context * ac,enum criteria * new_cr,ext4_group_t * group,ext4_group_t ngroups)872 static void ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context *ac,
873 			enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
874 {
875 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
876 	struct ext4_group_info *iter;
877 	int i;
878 
879 	if (ac->ac_status == AC_STATUS_FOUND)
880 		return;
881 
882 	if (unlikely(sbi->s_mb_stats && ac->ac_flags & EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED))
883 		atomic_inc(&sbi->s_bal_p2_aligned_bad_suggestions);
884 
885 	for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) {
886 		if (list_empty(&sbi->s_mb_largest_free_orders[i]))
887 			continue;
888 		read_lock(&sbi->s_mb_largest_free_orders_locks[i]);
889 		if (list_empty(&sbi->s_mb_largest_free_orders[i])) {
890 			read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
891 			continue;
892 		}
893 		list_for_each_entry(iter, &sbi->s_mb_largest_free_orders[i],
894 				    bb_largest_free_order_node) {
895 			if (sbi->s_mb_stats)
896 				atomic64_inc(&sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]);
897 			if (likely(ext4_mb_good_group(ac, iter->bb_group, CR_POWER2_ALIGNED))) {
898 				*group = iter->bb_group;
899 				ac->ac_flags |= EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED;
900 				read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
901 				return;
902 			}
903 		}
904 		read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
905 	}
906 
907 	/* Increment cr and search again if no group is found */
908 	*new_cr = CR_GOAL_LEN_FAST;
909 }
910 
911 /*
912  * Find a suitable group of given order from the average fragments list.
913  */
914 static struct ext4_group_info *
ext4_mb_find_good_group_avg_frag_lists(struct ext4_allocation_context * ac,int order)915 ext4_mb_find_good_group_avg_frag_lists(struct ext4_allocation_context *ac, int order)
916 {
917 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
918 	struct list_head *frag_list = &sbi->s_mb_avg_fragment_size[order];
919 	rwlock_t *frag_list_lock = &sbi->s_mb_avg_fragment_size_locks[order];
920 	struct ext4_group_info *grp = NULL, *iter;
921 	enum criteria cr = ac->ac_criteria;
922 
923 	if (list_empty(frag_list))
924 		return NULL;
925 	read_lock(frag_list_lock);
926 	if (list_empty(frag_list)) {
927 		read_unlock(frag_list_lock);
928 		return NULL;
929 	}
930 	list_for_each_entry(iter, frag_list, bb_avg_fragment_size_node) {
931 		if (sbi->s_mb_stats)
932 			atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]);
933 		if (likely(ext4_mb_good_group(ac, iter->bb_group, cr))) {
934 			grp = iter;
935 			break;
936 		}
937 	}
938 	read_unlock(frag_list_lock);
939 	return grp;
940 }
941 
942 /*
943  * Choose next group by traversing average fragment size list of suitable
944  * order. Updates *new_cr if cr level needs an update.
945  */
ext4_mb_choose_next_group_goal_fast(struct ext4_allocation_context * ac,enum criteria * new_cr,ext4_group_t * group,ext4_group_t ngroups)946 static void ext4_mb_choose_next_group_goal_fast(struct ext4_allocation_context *ac,
947 		enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
948 {
949 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
950 	struct ext4_group_info *grp = NULL;
951 	int i;
952 
953 	if (unlikely(ac->ac_flags & EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED)) {
954 		if (sbi->s_mb_stats)
955 			atomic_inc(&sbi->s_bal_goal_fast_bad_suggestions);
956 	}
957 
958 	for (i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len);
959 	     i < MB_NUM_ORDERS(ac->ac_sb); i++) {
960 		grp = ext4_mb_find_good_group_avg_frag_lists(ac, i);
961 		if (grp) {
962 			*group = grp->bb_group;
963 			ac->ac_flags |= EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED;
964 			return;
965 		}
966 	}
967 
968 	/*
969 	 * CR_BEST_AVAIL_LEN works based on the concept that we have
970 	 * a larger normalized goal len request which can be trimmed to
971 	 * a smaller goal len such that it can still satisfy original
972 	 * request len. However, allocation request for non-regular
973 	 * files never gets normalized.
974 	 * See function ext4_mb_normalize_request() (EXT4_MB_HINT_DATA).
975 	 */
976 	if (ac->ac_flags & EXT4_MB_HINT_DATA)
977 		*new_cr = CR_BEST_AVAIL_LEN;
978 	else
979 		*new_cr = CR_GOAL_LEN_SLOW;
980 }
981 
982 /*
983  * We couldn't find a group in CR_GOAL_LEN_FAST so try to find the highest free fragment
984  * order we have and proactively trim the goal request length to that order to
985  * find a suitable group faster.
986  *
987  * This optimizes allocation speed at the cost of slightly reduced
988  * preallocations. However, we make sure that we don't trim the request too
989  * much and fall to CR_GOAL_LEN_SLOW in that case.
990  */
ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context * ac,enum criteria * new_cr,ext4_group_t * group,ext4_group_t ngroups)991 static void ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context *ac,
992 		enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
993 {
994 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
995 	struct ext4_group_info *grp = NULL;
996 	int i, order, min_order;
997 	unsigned long num_stripe_clusters = 0;
998 
999 	if (unlikely(ac->ac_flags & EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED)) {
1000 		if (sbi->s_mb_stats)
1001 			atomic_inc(&sbi->s_bal_best_avail_bad_suggestions);
1002 	}
1003 
1004 	/*
1005 	 * mb_avg_fragment_size_order() returns order in a way that makes
1006 	 * retrieving back the length using (1 << order) inaccurate. Hence, use
1007 	 * fls() instead since we need to know the actual length while modifying
1008 	 * goal length.
1009 	 */
1010 	order = fls(ac->ac_g_ex.fe_len) - 1;
1011 	min_order = order - sbi->s_mb_best_avail_max_trim_order;
1012 	if (min_order < 0)
1013 		min_order = 0;
1014 
1015 	if (sbi->s_stripe > 0) {
1016 		/*
1017 		 * We are assuming that stripe size is always a multiple of
1018 		 * cluster ratio otherwise __ext4_fill_super exists early.
1019 		 */
1020 		num_stripe_clusters = EXT4_NUM_B2C(sbi, sbi->s_stripe);
1021 		if (1 << min_order < num_stripe_clusters)
1022 			/*
1023 			 * We consider 1 order less because later we round
1024 			 * up the goal len to num_stripe_clusters
1025 			 */
1026 			min_order = fls(num_stripe_clusters) - 1;
1027 	}
1028 
1029 	if (1 << min_order < ac->ac_o_ex.fe_len)
1030 		min_order = fls(ac->ac_o_ex.fe_len);
1031 
1032 	for (i = order; i >= min_order; i--) {
1033 		int frag_order;
1034 		/*
1035 		 * Scale down goal len to make sure we find something
1036 		 * in the free fragments list. Basically, reduce
1037 		 * preallocations.
1038 		 */
1039 		ac->ac_g_ex.fe_len = 1 << i;
1040 
1041 		if (num_stripe_clusters > 0) {
1042 			/*
1043 			 * Try to round up the adjusted goal length to
1044 			 * stripe size (in cluster units) multiple for
1045 			 * efficiency.
1046 			 */
1047 			ac->ac_g_ex.fe_len = roundup(ac->ac_g_ex.fe_len,
1048 						     num_stripe_clusters);
1049 		}
1050 
1051 		frag_order = mb_avg_fragment_size_order(ac->ac_sb,
1052 							ac->ac_g_ex.fe_len);
1053 
1054 		grp = ext4_mb_find_good_group_avg_frag_lists(ac, frag_order);
1055 		if (grp) {
1056 			*group = grp->bb_group;
1057 			ac->ac_flags |= EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED;
1058 			return;
1059 		}
1060 	}
1061 
1062 	/* Reset goal length to original goal length before falling into CR_GOAL_LEN_SLOW */
1063 	ac->ac_g_ex.fe_len = ac->ac_orig_goal_len;
1064 	*new_cr = CR_GOAL_LEN_SLOW;
1065 }
1066 
should_optimize_scan(struct ext4_allocation_context * ac)1067 static inline int should_optimize_scan(struct ext4_allocation_context *ac)
1068 {
1069 	if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN)))
1070 		return 0;
1071 	if (ac->ac_criteria >= CR_GOAL_LEN_SLOW)
1072 		return 0;
1073 	if (!ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))
1074 		return 0;
1075 	return 1;
1076 }
1077 
1078 /*
1079  * Return next linear group for allocation. If linear traversal should not be
1080  * performed, this function just returns the same group
1081  */
1082 static ext4_group_t
next_linear_group(struct ext4_allocation_context * ac,ext4_group_t group,ext4_group_t ngroups)1083 next_linear_group(struct ext4_allocation_context *ac, ext4_group_t group,
1084 		  ext4_group_t ngroups)
1085 {
1086 	if (!should_optimize_scan(ac))
1087 		goto inc_and_return;
1088 
1089 	if (ac->ac_groups_linear_remaining) {
1090 		ac->ac_groups_linear_remaining--;
1091 		goto inc_and_return;
1092 	}
1093 
1094 	return group;
1095 inc_and_return:
1096 	/*
1097 	 * Artificially restricted ngroups for non-extent
1098 	 * files makes group > ngroups possible on first loop.
1099 	 */
1100 	return group + 1 >= ngroups ? 0 : group + 1;
1101 }
1102 
1103 /*
1104  * ext4_mb_choose_next_group: choose next group for allocation.
1105  *
1106  * @ac        Allocation Context
1107  * @new_cr    This is an output parameter. If the there is no good group
1108  *            available at current CR level, this field is updated to indicate
1109  *            the new cr level that should be used.
1110  * @group     This is an input / output parameter. As an input it indicates the
1111  *            next group that the allocator intends to use for allocation. As
1112  *            output, this field indicates the next group that should be used as
1113  *            determined by the optimization functions.
1114  * @ngroups   Total number of groups
1115  */
ext4_mb_choose_next_group(struct ext4_allocation_context * ac,enum criteria * new_cr,ext4_group_t * group,ext4_group_t ngroups)1116 static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac,
1117 		enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
1118 {
1119 	*new_cr = ac->ac_criteria;
1120 
1121 	if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) {
1122 		*group = next_linear_group(ac, *group, ngroups);
1123 		return;
1124 	}
1125 
1126 	if (*new_cr == CR_POWER2_ALIGNED) {
1127 		ext4_mb_choose_next_group_p2_aligned(ac, new_cr, group, ngroups);
1128 	} else if (*new_cr == CR_GOAL_LEN_FAST) {
1129 		ext4_mb_choose_next_group_goal_fast(ac, new_cr, group, ngroups);
1130 	} else if (*new_cr == CR_BEST_AVAIL_LEN) {
1131 		ext4_mb_choose_next_group_best_avail(ac, new_cr, group, ngroups);
1132 	} else {
1133 		/*
1134 		 * TODO: For CR=2, we can arrange groups in an rb tree sorted by
1135 		 * bb_free. But until that happens, we should never come here.
1136 		 */
1137 		WARN_ON(1);
1138 	}
1139 }
1140 
1141 /*
1142  * Cache the order of the largest free extent we have available in this block
1143  * group.
1144  */
1145 static void
mb_set_largest_free_order(struct super_block * sb,struct ext4_group_info * grp)1146 mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
1147 {
1148 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1149 	int i;
1150 
1151 	for (i = MB_NUM_ORDERS(sb) - 1; i >= 0; i--)
1152 		if (grp->bb_counters[i] > 0)
1153 			break;
1154 	/* No need to move between order lists? */
1155 	if (!test_opt2(sb, MB_OPTIMIZE_SCAN) ||
1156 	    i == grp->bb_largest_free_order) {
1157 		grp->bb_largest_free_order = i;
1158 		return;
1159 	}
1160 
1161 	if (grp->bb_largest_free_order >= 0) {
1162 		write_lock(&sbi->s_mb_largest_free_orders_locks[
1163 					      grp->bb_largest_free_order]);
1164 		list_del_init(&grp->bb_largest_free_order_node);
1165 		write_unlock(&sbi->s_mb_largest_free_orders_locks[
1166 					      grp->bb_largest_free_order]);
1167 	}
1168 	grp->bb_largest_free_order = i;
1169 	if (grp->bb_largest_free_order >= 0 && grp->bb_free) {
1170 		write_lock(&sbi->s_mb_largest_free_orders_locks[
1171 					      grp->bb_largest_free_order]);
1172 		list_add_tail(&grp->bb_largest_free_order_node,
1173 		      &sbi->s_mb_largest_free_orders[grp->bb_largest_free_order]);
1174 		write_unlock(&sbi->s_mb_largest_free_orders_locks[
1175 					      grp->bb_largest_free_order]);
1176 	}
1177 }
1178 
1179 static noinline_for_stack
ext4_mb_generate_buddy(struct super_block * sb,void * buddy,void * bitmap,ext4_group_t group,struct ext4_group_info * grp)1180 void ext4_mb_generate_buddy(struct super_block *sb,
1181 			    void *buddy, void *bitmap, ext4_group_t group,
1182 			    struct ext4_group_info *grp)
1183 {
1184 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1185 	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
1186 	ext4_grpblk_t i = 0;
1187 	ext4_grpblk_t first;
1188 	ext4_grpblk_t len;
1189 	unsigned free = 0;
1190 	unsigned fragments = 0;
1191 	unsigned long long period = get_cycles();
1192 
1193 	/* initialize buddy from bitmap which is aggregation
1194 	 * of on-disk bitmap and preallocations */
1195 	i = mb_find_next_zero_bit(bitmap, max, 0);
1196 	grp->bb_first_free = i;
1197 	while (i < max) {
1198 		fragments++;
1199 		first = i;
1200 		i = mb_find_next_bit(bitmap, max, i);
1201 		len = i - first;
1202 		free += len;
1203 		if (len > 1)
1204 			ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
1205 		else
1206 			grp->bb_counters[0]++;
1207 		if (i < max)
1208 			i = mb_find_next_zero_bit(bitmap, max, i);
1209 	}
1210 	grp->bb_fragments = fragments;
1211 
1212 	if (free != grp->bb_free) {
1213 		ext4_grp_locked_error(sb, group, 0, 0,
1214 				      "block bitmap and bg descriptor "
1215 				      "inconsistent: %u vs %u free clusters",
1216 				      free, grp->bb_free);
1217 		/*
1218 		 * If we intend to continue, we consider group descriptor
1219 		 * corrupt and update bb_free using bitmap value
1220 		 */
1221 		grp->bb_free = free;
1222 		ext4_mark_group_bitmap_corrupted(sb, group,
1223 					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
1224 	}
1225 	mb_set_largest_free_order(sb, grp);
1226 	mb_update_avg_fragment_size(sb, grp);
1227 
1228 	clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
1229 
1230 	period = get_cycles() - period;
1231 	atomic_inc(&sbi->s_mb_buddies_generated);
1232 	atomic64_add(period, &sbi->s_mb_generation_time);
1233 }
1234 
mb_regenerate_buddy(struct ext4_buddy * e4b)1235 static void mb_regenerate_buddy(struct ext4_buddy *e4b)
1236 {
1237 	int count;
1238 	int order = 1;
1239 	void *buddy;
1240 
1241 	while ((buddy = mb_find_buddy(e4b, order++, &count)))
1242 		mb_set_bits(buddy, 0, count);
1243 
1244 	e4b->bd_info->bb_fragments = 0;
1245 	memset(e4b->bd_info->bb_counters, 0,
1246 		sizeof(*e4b->bd_info->bb_counters) *
1247 		(e4b->bd_sb->s_blocksize_bits + 2));
1248 
1249 	ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
1250 		e4b->bd_bitmap, e4b->bd_group, e4b->bd_info);
1251 }
1252 
1253 /* The buddy information is attached the buddy cache inode
1254  * for convenience. The information regarding each group
1255  * is loaded via ext4_mb_load_buddy. The information involve
1256  * block bitmap and buddy information. The information are
1257  * stored in the inode as
1258  *
1259  * {                        page                        }
1260  * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
1261  *
1262  *
1263  * one block each for bitmap and buddy information.
1264  * So for each group we take up 2 blocks. A page can
1265  * contain blocks_per_page (PAGE_SIZE / blocksize)  blocks.
1266  * So it can have information regarding groups_per_page which
1267  * is blocks_per_page/2
1268  *
1269  * Locking note:  This routine takes the block group lock of all groups
1270  * for this page; do not hold this lock when calling this routine!
1271  */
1272 
ext4_mb_init_cache(struct page * page,char * incore,gfp_t gfp)1273 static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
1274 {
1275 	ext4_group_t ngroups;
1276 	unsigned int blocksize;
1277 	int blocks_per_page;
1278 	int groups_per_page;
1279 	int err = 0;
1280 	int i;
1281 	ext4_group_t first_group, group;
1282 	int first_block;
1283 	struct super_block *sb;
1284 	struct buffer_head *bhs;
1285 	struct buffer_head **bh = NULL;
1286 	struct inode *inode;
1287 	char *data;
1288 	char *bitmap;
1289 	struct ext4_group_info *grinfo;
1290 
1291 	inode = page->mapping->host;
1292 	sb = inode->i_sb;
1293 	ngroups = ext4_get_groups_count(sb);
1294 	blocksize = i_blocksize(inode);
1295 	blocks_per_page = PAGE_SIZE / blocksize;
1296 
1297 	mb_debug(sb, "init page %lu\n", page->index);
1298 
1299 	groups_per_page = blocks_per_page >> 1;
1300 	if (groups_per_page == 0)
1301 		groups_per_page = 1;
1302 
1303 	/* allocate buffer_heads to read bitmaps */
1304 	if (groups_per_page > 1) {
1305 		i = sizeof(struct buffer_head *) * groups_per_page;
1306 		bh = kzalloc(i, gfp);
1307 		if (bh == NULL)
1308 			return -ENOMEM;
1309 	} else
1310 		bh = &bhs;
1311 
1312 	first_group = page->index * blocks_per_page / 2;
1313 
1314 	/* read all groups the page covers into the cache */
1315 	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
1316 		if (group >= ngroups)
1317 			break;
1318 
1319 		grinfo = ext4_get_group_info(sb, group);
1320 		if (!grinfo)
1321 			continue;
1322 		/*
1323 		 * If page is uptodate then we came here after online resize
1324 		 * which added some new uninitialized group info structs, so
1325 		 * we must skip all initialized uptodate buddies on the page,
1326 		 * which may be currently in use by an allocating task.
1327 		 */
1328 		if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
1329 			bh[i] = NULL;
1330 			continue;
1331 		}
1332 		bh[i] = ext4_read_block_bitmap_nowait(sb, group, false);
1333 		if (IS_ERR(bh[i])) {
1334 			err = PTR_ERR(bh[i]);
1335 			bh[i] = NULL;
1336 			goto out;
1337 		}
1338 		mb_debug(sb, "read bitmap for group %u\n", group);
1339 	}
1340 
1341 	/* wait for I/O completion */
1342 	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
1343 		int err2;
1344 
1345 		if (!bh[i])
1346 			continue;
1347 		err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
1348 		if (!err)
1349 			err = err2;
1350 	}
1351 
1352 	first_block = page->index * blocks_per_page;
1353 	for (i = 0; i < blocks_per_page; i++) {
1354 		group = (first_block + i) >> 1;
1355 		if (group >= ngroups)
1356 			break;
1357 
1358 		if (!bh[group - first_group])
1359 			/* skip initialized uptodate buddy */
1360 			continue;
1361 
1362 		if (!buffer_verified(bh[group - first_group]))
1363 			/* Skip faulty bitmaps */
1364 			continue;
1365 		err = 0;
1366 
1367 		/*
1368 		 * data carry information regarding this
1369 		 * particular group in the format specified
1370 		 * above
1371 		 *
1372 		 */
1373 		data = page_address(page) + (i * blocksize);
1374 		bitmap = bh[group - first_group]->b_data;
1375 
1376 		/*
1377 		 * We place the buddy block and bitmap block
1378 		 * close together
1379 		 */
1380 		grinfo = ext4_get_group_info(sb, group);
1381 		if (!grinfo) {
1382 			err = -EFSCORRUPTED;
1383 		        goto out;
1384 		}
1385 		if ((first_block + i) & 1) {
1386 			/* this is block of buddy */
1387 			BUG_ON(incore == NULL);
1388 			mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
1389 				group, page->index, i * blocksize);
1390 			trace_ext4_mb_buddy_bitmap_load(sb, group);
1391 			grinfo->bb_fragments = 0;
1392 			memset(grinfo->bb_counters, 0,
1393 			       sizeof(*grinfo->bb_counters) *
1394 			       (MB_NUM_ORDERS(sb)));
1395 			/*
1396 			 * incore got set to the group block bitmap below
1397 			 */
1398 			ext4_lock_group(sb, group);
1399 			/* init the buddy */
1400 			memset(data, 0xff, blocksize);
1401 			ext4_mb_generate_buddy(sb, data, incore, group, grinfo);
1402 			ext4_unlock_group(sb, group);
1403 			incore = NULL;
1404 		} else {
1405 			/* this is block of bitmap */
1406 			BUG_ON(incore != NULL);
1407 			mb_debug(sb, "put bitmap for group %u in page %lu/%x\n",
1408 				group, page->index, i * blocksize);
1409 			trace_ext4_mb_bitmap_load(sb, group);
1410 
1411 			/* see comments in ext4_mb_put_pa() */
1412 			ext4_lock_group(sb, group);
1413 			memcpy(data, bitmap, blocksize);
1414 
1415 			/* mark all preallocated blks used in in-core bitmap */
1416 			ext4_mb_generate_from_pa(sb, data, group);
1417 			WARN_ON_ONCE(!RB_EMPTY_ROOT(&grinfo->bb_free_root));
1418 			ext4_unlock_group(sb, group);
1419 
1420 			/* set incore so that the buddy information can be
1421 			 * generated using this
1422 			 */
1423 			incore = data;
1424 		}
1425 	}
1426 	SetPageUptodate(page);
1427 
1428 out:
1429 	if (bh) {
1430 		for (i = 0; i < groups_per_page; i++)
1431 			brelse(bh[i]);
1432 		if (bh != &bhs)
1433 			kfree(bh);
1434 	}
1435 	return err;
1436 }
1437 
1438 /*
1439  * Lock the buddy and bitmap pages. This make sure other parallel init_group
1440  * on the same buddy page doesn't happen whild holding the buddy page lock.
1441  * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
1442  * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
1443  */
ext4_mb_get_buddy_page_lock(struct super_block * sb,ext4_group_t group,struct ext4_buddy * e4b,gfp_t gfp)1444 static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
1445 		ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
1446 {
1447 	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
1448 	int block, pnum, poff;
1449 	int blocks_per_page;
1450 	struct page *page;
1451 
1452 	e4b->bd_buddy_page = NULL;
1453 	e4b->bd_bitmap_page = NULL;
1454 
1455 	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
1456 	/*
1457 	 * the buddy cache inode stores the block bitmap
1458 	 * and buddy information in consecutive blocks.
1459 	 * So for each group we need two blocks.
1460 	 */
1461 	block = group * 2;
1462 	pnum = block / blocks_per_page;
1463 	poff = block % blocks_per_page;
1464 	page = find_or_create_page(inode->i_mapping, pnum, gfp);
1465 	if (!page)
1466 		return -ENOMEM;
1467 	BUG_ON(page->mapping != inode->i_mapping);
1468 	e4b->bd_bitmap_page = page;
1469 	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1470 
1471 	if (blocks_per_page >= 2) {
1472 		/* buddy and bitmap are on the same page */
1473 		return 0;
1474 	}
1475 
1476 	block++;
1477 	pnum = block / blocks_per_page;
1478 	page = find_or_create_page(inode->i_mapping, pnum, gfp);
1479 	if (!page)
1480 		return -ENOMEM;
1481 	BUG_ON(page->mapping != inode->i_mapping);
1482 	e4b->bd_buddy_page = page;
1483 	return 0;
1484 }
1485 
ext4_mb_put_buddy_page_lock(struct ext4_buddy * e4b)1486 static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
1487 {
1488 	if (e4b->bd_bitmap_page) {
1489 		unlock_page(e4b->bd_bitmap_page);
1490 		put_page(e4b->bd_bitmap_page);
1491 	}
1492 	if (e4b->bd_buddy_page) {
1493 		unlock_page(e4b->bd_buddy_page);
1494 		put_page(e4b->bd_buddy_page);
1495 	}
1496 }
1497 
1498 /*
1499  * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
1500  * block group lock of all groups for this page; do not hold the BG lock when
1501  * calling this routine!
1502  */
1503 static noinline_for_stack
ext4_mb_init_group(struct super_block * sb,ext4_group_t group,gfp_t gfp)1504 int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
1505 {
1506 
1507 	struct ext4_group_info *this_grp;
1508 	struct ext4_buddy e4b;
1509 	struct page *page;
1510 	int ret = 0;
1511 
1512 	might_sleep();
1513 	mb_debug(sb, "init group %u\n", group);
1514 	this_grp = ext4_get_group_info(sb, group);
1515 	if (!this_grp)
1516 		return -EFSCORRUPTED;
1517 
1518 	/*
1519 	 * This ensures that we don't reinit the buddy cache
1520 	 * page which map to the group from which we are already
1521 	 * allocating. If we are looking at the buddy cache we would
1522 	 * have taken a reference using ext4_mb_load_buddy and that
1523 	 * would have pinned buddy page to page cache.
1524 	 * The call to ext4_mb_get_buddy_page_lock will mark the
1525 	 * page accessed.
1526 	 */
1527 	ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
1528 	if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1529 		/*
1530 		 * somebody initialized the group
1531 		 * return without doing anything
1532 		 */
1533 		goto err;
1534 	}
1535 
1536 	page = e4b.bd_bitmap_page;
1537 	ret = ext4_mb_init_cache(page, NULL, gfp);
1538 	if (ret)
1539 		goto err;
1540 	if (!PageUptodate(page)) {
1541 		ret = -EIO;
1542 		goto err;
1543 	}
1544 
1545 	if (e4b.bd_buddy_page == NULL) {
1546 		/*
1547 		 * If both the bitmap and buddy are in
1548 		 * the same page we don't need to force
1549 		 * init the buddy
1550 		 */
1551 		ret = 0;
1552 		goto err;
1553 	}
1554 	/* init buddy cache */
1555 	page = e4b.bd_buddy_page;
1556 	ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
1557 	if (ret)
1558 		goto err;
1559 	if (!PageUptodate(page)) {
1560 		ret = -EIO;
1561 		goto err;
1562 	}
1563 err:
1564 	ext4_mb_put_buddy_page_lock(&e4b);
1565 	return ret;
1566 }
1567 
1568 /*
1569  * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
1570  * block group lock of all groups for this page; do not hold the BG lock when
1571  * calling this routine!
1572  */
1573 static noinline_for_stack int
ext4_mb_load_buddy_gfp(struct super_block * sb,ext4_group_t group,struct ext4_buddy * e4b,gfp_t gfp)1574 ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
1575 		       struct ext4_buddy *e4b, gfp_t gfp)
1576 {
1577 	int blocks_per_page;
1578 	int block;
1579 	int pnum;
1580 	int poff;
1581 	struct page *page;
1582 	int ret;
1583 	struct ext4_group_info *grp;
1584 	struct ext4_sb_info *sbi = EXT4_SB(sb);
1585 	struct inode *inode = sbi->s_buddy_cache;
1586 
1587 	might_sleep();
1588 	mb_debug(sb, "load group %u\n", group);
1589 
1590 	blocks_per_page = PAGE_SIZE / sb->s_blocksize;
1591 	grp = ext4_get_group_info(sb, group);
1592 	if (!grp)
1593 		return -EFSCORRUPTED;
1594 
1595 	e4b->bd_blkbits = sb->s_blocksize_bits;
1596 	e4b->bd_info = grp;
1597 	e4b->bd_sb = sb;
1598 	e4b->bd_group = group;
1599 	e4b->bd_buddy_page = NULL;
1600 	e4b->bd_bitmap_page = NULL;
1601 
1602 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
1603 		/*
1604 		 * we need full data about the group
1605 		 * to make a good selection
1606 		 */
1607 		ret = ext4_mb_init_group(sb, group, gfp);
1608 		if (ret)
1609 			return ret;
1610 	}
1611 
1612 	/*
1613 	 * the buddy cache inode stores the block bitmap
1614 	 * and buddy information in consecutive blocks.
1615 	 * So for each group we need two blocks.
1616 	 */
1617 	block = group * 2;
1618 	pnum = block / blocks_per_page;
1619 	poff = block % blocks_per_page;
1620 
1621 	/* we could use find_or_create_page(), but it locks page
1622 	 * what we'd like to avoid in fast path ... */
1623 	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1624 	if (page == NULL || !PageUptodate(page)) {
1625 		if (page)
1626 			/*
1627 			 * drop the page reference and try
1628 			 * to get the page with lock. If we
1629 			 * are not uptodate that implies
1630 			 * somebody just created the page but
1631 			 * is yet to initialize the same. So
1632 			 * wait for it to initialize.
1633 			 */
1634 			put_page(page);
1635 		page = find_or_create_page(inode->i_mapping, pnum, gfp);
1636 		if (page) {
1637 			if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
1638 	"ext4: bitmap's paging->mapping != inode->i_mapping\n")) {
1639 				/* should never happen */
1640 				unlock_page(page);
1641 				ret = -EINVAL;
1642 				goto err;
1643 			}
1644 			if (!PageUptodate(page)) {
1645 				ret = ext4_mb_init_cache(page, NULL, gfp);
1646 				if (ret) {
1647 					unlock_page(page);
1648 					goto err;
1649 				}
1650 				mb_cmp_bitmaps(e4b, page_address(page) +
1651 					       (poff * sb->s_blocksize));
1652 			}
1653 			unlock_page(page);
1654 		}
1655 	}
1656 	if (page == NULL) {
1657 		ret = -ENOMEM;
1658 		goto err;
1659 	}
1660 	if (!PageUptodate(page)) {
1661 		ret = -EIO;
1662 		goto err;
1663 	}
1664 
1665 	/* Pages marked accessed already */
1666 	e4b->bd_bitmap_page = page;
1667 	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1668 
1669 	block++;
1670 	pnum = block / blocks_per_page;
1671 	poff = block % blocks_per_page;
1672 
1673 	page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1674 	if (page == NULL || !PageUptodate(page)) {
1675 		if (page)
1676 			put_page(page);
1677 		page = find_or_create_page(inode->i_mapping, pnum, gfp);
1678 		if (page) {
1679 			if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
1680 	"ext4: buddy bitmap's page->mapping != inode->i_mapping\n")) {
1681 				/* should never happen */
1682 				unlock_page(page);
1683 				ret = -EINVAL;
1684 				goto err;
1685 			}
1686 			if (!PageUptodate(page)) {
1687 				ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
1688 							 gfp);
1689 				if (ret) {
1690 					unlock_page(page);
1691 					goto err;
1692 				}
1693 			}
1694 			unlock_page(page);
1695 		}
1696 	}
1697 	if (page == NULL) {
1698 		ret = -ENOMEM;
1699 		goto err;
1700 	}
1701 	if (!PageUptodate(page)) {
1702 		ret = -EIO;
1703 		goto err;
1704 	}
1705 
1706 	/* Pages marked accessed already */
1707 	e4b->bd_buddy_page = page;
1708 	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
1709 
1710 	return 0;
1711 
1712 err:
1713 	if (page)
1714 		put_page(page);
1715 	if (e4b->bd_bitmap_page)
1716 		put_page(e4b->bd_bitmap_page);
1717 
1718 	e4b->bd_buddy = NULL;
1719 	e4b->bd_bitmap = NULL;
1720 	return ret;
1721 }
1722 
ext4_mb_load_buddy(struct super_block * sb,ext4_group_t group,struct ext4_buddy * e4b)1723 static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
1724 			      struct ext4_buddy *e4b)
1725 {
1726 	return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
1727 }
1728 
ext4_mb_unload_buddy(struct ext4_buddy * e4b)1729 static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1730 {
1731 	if (e4b->bd_bitmap_page)
1732 		put_page(e4b->bd_bitmap_page);
1733 	if (e4b->bd_buddy_page)
1734 		put_page(e4b->bd_buddy_page);
1735 }
1736 
1737 
mb_find_order_for_block(struct ext4_buddy * e4b,int block)1738 static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
1739 {
1740 	int order = 1, max;
1741 	void *bb;
1742 
1743 	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
1744 	BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
1745 
1746 	while (order <= e4b->bd_blkbits + 1) {
1747 		bb = mb_find_buddy(e4b, order, &max);
1748 		if (!mb_test_bit(block >> order, bb)) {
1749 			/* this block is part of buddy of order 'order' */
1750 			return order;
1751 		}
1752 		order++;
1753 	}
1754 	return 0;
1755 }
1756 
mb_clear_bits(void * bm,int cur,int len)1757 static void mb_clear_bits(void *bm, int cur, int len)
1758 {
1759 	__u32 *addr;
1760 
1761 	len = cur + len;
1762 	while (cur < len) {
1763 		if ((cur & 31) == 0 && (len - cur) >= 32) {
1764 			/* fast path: clear whole word at once */
1765 			addr = bm + (cur >> 3);
1766 			*addr = 0;
1767 			cur += 32;
1768 			continue;
1769 		}
1770 		mb_clear_bit(cur, bm);
1771 		cur++;
1772 	}
1773 }
1774 
1775 /* clear bits in given range
1776  * will return first found zero bit if any, -1 otherwise
1777  */
mb_test_and_clear_bits(void * bm,int cur,int len)1778 static int mb_test_and_clear_bits(void *bm, int cur, int len)
1779 {
1780 	__u32 *addr;
1781 	int zero_bit = -1;
1782 
1783 	len = cur + len;
1784 	while (cur < len) {
1785 		if ((cur & 31) == 0 && (len - cur) >= 32) {
1786 			/* fast path: clear whole word at once */
1787 			addr = bm + (cur >> 3);
1788 			if (*addr != (__u32)(-1) && zero_bit == -1)
1789 				zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
1790 			*addr = 0;
1791 			cur += 32;
1792 			continue;
1793 		}
1794 		if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
1795 			zero_bit = cur;
1796 		cur++;
1797 	}
1798 
1799 	return zero_bit;
1800 }
1801 
mb_set_bits(void * bm,int cur,int len)1802 void mb_set_bits(void *bm, int cur, int len)
1803 {
1804 	__u32 *addr;
1805 
1806 	len = cur + len;
1807 	while (cur < len) {
1808 		if ((cur & 31) == 0 && (len - cur) >= 32) {
1809 			/* fast path: set whole word at once */
1810 			addr = bm + (cur >> 3);
1811 			*addr = 0xffffffff;
1812 			cur += 32;
1813 			continue;
1814 		}
1815 		mb_set_bit(cur, bm);
1816 		cur++;
1817 	}
1818 }
1819 
mb_buddy_adjust_border(int * bit,void * bitmap,int side)1820 static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
1821 {
1822 	if (mb_test_bit(*bit + side, bitmap)) {
1823 		mb_clear_bit(*bit, bitmap);
1824 		(*bit) -= side;
1825 		return 1;
1826 	}
1827 	else {
1828 		(*bit) += side;
1829 		mb_set_bit(*bit, bitmap);
1830 		return -1;
1831 	}
1832 }
1833 
mb_buddy_mark_free(struct ext4_buddy * e4b,int first,int last)1834 static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
1835 {
1836 	int max;
1837 	int order = 1;
1838 	void *buddy = mb_find_buddy(e4b, order, &max);
1839 
1840 	while (buddy) {
1841 		void *buddy2;
1842 
1843 		/* Bits in range [first; last] are known to be set since
1844 		 * corresponding blocks were allocated. Bits in range
1845 		 * (first; last) will stay set because they form buddies on
1846 		 * upper layer. We just deal with borders if they don't
1847 		 * align with upper layer and then go up.
1848 		 * Releasing entire group is all about clearing
1849 		 * single bit of highest order buddy.
1850 		 */
1851 
1852 		/* Example:
1853 		 * ---------------------------------
1854 		 * |   1   |   1   |   1   |   1   |
1855 		 * ---------------------------------
1856 		 * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1857 		 * ---------------------------------
1858 		 *   0   1   2   3   4   5   6   7
1859 		 *      \_____________________/
1860 		 *
1861 		 * Neither [1] nor [6] is aligned to above layer.
1862 		 * Left neighbour [0] is free, so mark it busy,
1863 		 * decrease bb_counters and extend range to
1864 		 * [0; 6]
1865 		 * Right neighbour [7] is busy. It can't be coaleasced with [6], so
1866 		 * mark [6] free, increase bb_counters and shrink range to
1867 		 * [0; 5].
1868 		 * Then shift range to [0; 2], go up and do the same.
1869 		 */
1870 
1871 
1872 		if (first & 1)
1873 			e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
1874 		if (!(last & 1))
1875 			e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
1876 		if (first > last)
1877 			break;
1878 		order++;
1879 
1880 		buddy2 = mb_find_buddy(e4b, order, &max);
1881 		if (!buddy2) {
1882 			mb_clear_bits(buddy, first, last - first + 1);
1883 			e4b->bd_info->bb_counters[order - 1] += last - first + 1;
1884 			break;
1885 		}
1886 		first >>= 1;
1887 		last >>= 1;
1888 		buddy = buddy2;
1889 	}
1890 }
1891 
mb_free_blocks(struct inode * inode,struct ext4_buddy * e4b,int first,int count)1892 static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1893 			   int first, int count)
1894 {
1895 	int left_is_free = 0;
1896 	int right_is_free = 0;
1897 	int block;
1898 	int last = first + count - 1;
1899 	struct super_block *sb = e4b->bd_sb;
1900 
1901 	if (WARN_ON(count == 0))
1902 		return;
1903 	BUG_ON(last >= (sb->s_blocksize << 3));
1904 	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1905 	/* Don't bother if the block group is corrupt. */
1906 	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
1907 		return;
1908 
1909 	mb_check_buddy(e4b);
1910 	mb_free_blocks_double(inode, e4b, first, count);
1911 
1912 	/* access memory sequentially: check left neighbour,
1913 	 * clear range and then check right neighbour
1914 	 */
1915 	if (first != 0)
1916 		left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
1917 	block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
1918 	if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
1919 		right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
1920 
1921 	if (unlikely(block != -1)) {
1922 		struct ext4_sb_info *sbi = EXT4_SB(sb);
1923 		ext4_fsblk_t blocknr;
1924 
1925 		/*
1926 		 * Fastcommit replay can free already freed blocks which
1927 		 * corrupts allocation info. Regenerate it.
1928 		 */
1929 		if (sbi->s_mount_state & EXT4_FC_REPLAY) {
1930 			mb_regenerate_buddy(e4b);
1931 			goto check;
1932 		}
1933 
1934 		blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1935 		blocknr += EXT4_C2B(sbi, block);
1936 		ext4_grp_locked_error(sb, e4b->bd_group,
1937 				      inode ? inode->i_ino : 0, blocknr,
1938 				      "freeing already freed block (bit %u); block bitmap corrupt.",
1939 				      block);
1940 		ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
1941 				EXT4_GROUP_INFO_BBITMAP_CORRUPT);
1942 		return;
1943 	}
1944 
1945 	this_cpu_inc(discard_pa_seq);
1946 	e4b->bd_info->bb_free += count;
1947 	if (first < e4b->bd_info->bb_first_free)
1948 		e4b->bd_info->bb_first_free = first;
1949 
1950 	/* let's maintain fragments counter */
1951 	if (left_is_free && right_is_free)
1952 		e4b->bd_info->bb_fragments--;
1953 	else if (!left_is_free && !right_is_free)
1954 		e4b->bd_info->bb_fragments++;
1955 
1956 	/* buddy[0] == bd_bitmap is a special case, so handle
1957 	 * it right away and let mb_buddy_mark_free stay free of
1958 	 * zero order checks.
1959 	 * Check if neighbours are to be coaleasced,
1960 	 * adjust bitmap bb_counters and borders appropriately.
1961 	 */
1962 	if (first & 1) {
1963 		first += !left_is_free;
1964 		e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
1965 	}
1966 	if (!(last & 1)) {
1967 		last -= !right_is_free;
1968 		e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
1969 	}
1970 
1971 	if (first <= last)
1972 		mb_buddy_mark_free(e4b, first >> 1, last >> 1);
1973 
1974 	mb_set_largest_free_order(sb, e4b->bd_info);
1975 	mb_update_avg_fragment_size(sb, e4b->bd_info);
1976 check:
1977 	mb_check_buddy(e4b);
1978 }
1979 
mb_find_extent(struct ext4_buddy * e4b,int block,int needed,struct ext4_free_extent * ex)1980 static int mb_find_extent(struct ext4_buddy *e4b, int block,
1981 				int needed, struct ext4_free_extent *ex)
1982 {
1983 	int next = block;
1984 	int max, order;
1985 	void *buddy;
1986 
1987 	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1988 	BUG_ON(ex == NULL);
1989 
1990 	buddy = mb_find_buddy(e4b, 0, &max);
1991 	BUG_ON(buddy == NULL);
1992 	BUG_ON(block >= max);
1993 	if (mb_test_bit(block, buddy)) {
1994 		ex->fe_len = 0;
1995 		ex->fe_start = 0;
1996 		ex->fe_group = 0;
1997 		return 0;
1998 	}
1999 
2000 	/* find actual order */
2001 	order = mb_find_order_for_block(e4b, block);
2002 	block = block >> order;
2003 
2004 	ex->fe_len = 1 << order;
2005 	ex->fe_start = block << order;
2006 	ex->fe_group = e4b->bd_group;
2007 
2008 	/* calc difference from given start */
2009 	next = next - ex->fe_start;
2010 	ex->fe_len -= next;
2011 	ex->fe_start += next;
2012 
2013 	while (needed > ex->fe_len &&
2014 	       mb_find_buddy(e4b, order, &max)) {
2015 
2016 		if (block + 1 >= max)
2017 			break;
2018 
2019 		next = (block + 1) * (1 << order);
2020 		if (mb_test_bit(next, e4b->bd_bitmap))
2021 			break;
2022 
2023 		order = mb_find_order_for_block(e4b, next);
2024 
2025 		block = next >> order;
2026 		ex->fe_len += 1 << order;
2027 	}
2028 
2029 	if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) {
2030 		/* Should never happen! (but apparently sometimes does?!?) */
2031 		WARN_ON(1);
2032 		ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0,
2033 			"corruption or bug in mb_find_extent "
2034 			"block=%d, order=%d needed=%d ex=%u/%d/%d@%u",
2035 			block, order, needed, ex->fe_group, ex->fe_start,
2036 			ex->fe_len, ex->fe_logical);
2037 		ex->fe_len = 0;
2038 		ex->fe_start = 0;
2039 		ex->fe_group = 0;
2040 	}
2041 	return ex->fe_len;
2042 }
2043 
mb_mark_used(struct ext4_buddy * e4b,struct ext4_free_extent * ex)2044 static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
2045 {
2046 	int ord;
2047 	int mlen = 0;
2048 	int max = 0;
2049 	int cur;
2050 	int start = ex->fe_start;
2051 	int len = ex->fe_len;
2052 	unsigned ret = 0;
2053 	int len0 = len;
2054 	void *buddy;
2055 	bool split = false;
2056 
2057 	BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
2058 	BUG_ON(e4b->bd_group != ex->fe_group);
2059 	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
2060 	mb_check_buddy(e4b);
2061 	mb_mark_used_double(e4b, start, len);
2062 
2063 	this_cpu_inc(discard_pa_seq);
2064 	e4b->bd_info->bb_free -= len;
2065 	if (e4b->bd_info->bb_first_free == start)
2066 		e4b->bd_info->bb_first_free += len;
2067 
2068 	/* let's maintain fragments counter */
2069 	if (start != 0)
2070 		mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
2071 	if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
2072 		max = !mb_test_bit(start + len, e4b->bd_bitmap);
2073 	if (mlen && max)
2074 		e4b->bd_info->bb_fragments++;
2075 	else if (!mlen && !max)
2076 		e4b->bd_info->bb_fragments--;
2077 
2078 	/* let's maintain buddy itself */
2079 	while (len) {
2080 		if (!split)
2081 			ord = mb_find_order_for_block(e4b, start);
2082 
2083 		if (((start >> ord) << ord) == start && len >= (1 << ord)) {
2084 			/* the whole chunk may be allocated at once! */
2085 			mlen = 1 << ord;
2086 			if (!split)
2087 				buddy = mb_find_buddy(e4b, ord, &max);
2088 			else
2089 				split = false;
2090 			BUG_ON((start >> ord) >= max);
2091 			mb_set_bit(start >> ord, buddy);
2092 			e4b->bd_info->bb_counters[ord]--;
2093 			start += mlen;
2094 			len -= mlen;
2095 			BUG_ON(len < 0);
2096 			continue;
2097 		}
2098 
2099 		/* store for history */
2100 		if (ret == 0)
2101 			ret = len | (ord << 16);
2102 
2103 		/* we have to split large buddy */
2104 		BUG_ON(ord <= 0);
2105 		buddy = mb_find_buddy(e4b, ord, &max);
2106 		mb_set_bit(start >> ord, buddy);
2107 		e4b->bd_info->bb_counters[ord]--;
2108 
2109 		ord--;
2110 		cur = (start >> ord) & ~1U;
2111 		buddy = mb_find_buddy(e4b, ord, &max);
2112 		mb_clear_bit(cur, buddy);
2113 		mb_clear_bit(cur + 1, buddy);
2114 		e4b->bd_info->bb_counters[ord]++;
2115 		e4b->bd_info->bb_counters[ord]++;
2116 		split = true;
2117 	}
2118 	mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
2119 
2120 	mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info);
2121 	mb_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
2122 	mb_check_buddy(e4b);
2123 
2124 	return ret;
2125 }
2126 
2127 /*
2128  * Must be called under group lock!
2129  */
ext4_mb_use_best_found(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)2130 static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
2131 					struct ext4_buddy *e4b)
2132 {
2133 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
2134 	int ret;
2135 
2136 	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
2137 	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
2138 
2139 	ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
2140 	ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
2141 	ret = mb_mark_used(e4b, &ac->ac_b_ex);
2142 
2143 	/* preallocation can change ac_b_ex, thus we store actually
2144 	 * allocated blocks for history */
2145 	ac->ac_f_ex = ac->ac_b_ex;
2146 
2147 	ac->ac_status = AC_STATUS_FOUND;
2148 	ac->ac_tail = ret & 0xffff;
2149 	ac->ac_buddy = ret >> 16;
2150 
2151 	/*
2152 	 * take the page reference. We want the page to be pinned
2153 	 * so that we don't get a ext4_mb_init_cache_call for this
2154 	 * group until we update the bitmap. That would mean we
2155 	 * double allocate blocks. The reference is dropped
2156 	 * in ext4_mb_release_context
2157 	 */
2158 	ac->ac_bitmap_page = e4b->bd_bitmap_page;
2159 	get_page(ac->ac_bitmap_page);
2160 	ac->ac_buddy_page = e4b->bd_buddy_page;
2161 	get_page(ac->ac_buddy_page);
2162 	/* store last allocated for subsequent stream allocation */
2163 	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
2164 		spin_lock(&sbi->s_md_lock);
2165 		sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
2166 		sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
2167 		spin_unlock(&sbi->s_md_lock);
2168 	}
2169 	/*
2170 	 * As we've just preallocated more space than
2171 	 * user requested originally, we store allocated
2172 	 * space in a special descriptor.
2173 	 */
2174 	if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
2175 		ext4_mb_new_preallocation(ac);
2176 
2177 }
2178 
ext4_mb_check_limits(struct ext4_allocation_context * ac,struct ext4_buddy * e4b,int finish_group)2179 static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
2180 					struct ext4_buddy *e4b,
2181 					int finish_group)
2182 {
2183 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
2184 	struct ext4_free_extent *bex = &ac->ac_b_ex;
2185 	struct ext4_free_extent *gex = &ac->ac_g_ex;
2186 
2187 	if (ac->ac_status == AC_STATUS_FOUND)
2188 		return;
2189 	/*
2190 	 * We don't want to scan for a whole year
2191 	 */
2192 	if (ac->ac_found > sbi->s_mb_max_to_scan &&
2193 			!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2194 		ac->ac_status = AC_STATUS_BREAK;
2195 		return;
2196 	}
2197 
2198 	/*
2199 	 * Haven't found good chunk so far, let's continue
2200 	 */
2201 	if (bex->fe_len < gex->fe_len)
2202 		return;
2203 
2204 	if (finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
2205 		ext4_mb_use_best_found(ac, e4b);
2206 }
2207 
2208 /*
2209  * The routine checks whether found extent is good enough. If it is,
2210  * then the extent gets marked used and flag is set to the context
2211  * to stop scanning. Otherwise, the extent is compared with the
2212  * previous found extent and if new one is better, then it's stored
2213  * in the context. Later, the best found extent will be used, if
2214  * mballoc can't find good enough extent.
2215  *
2216  * The algorithm used is roughly as follows:
2217  *
2218  * * If free extent found is exactly as big as goal, then
2219  *   stop the scan and use it immediately
2220  *
2221  * * If free extent found is smaller than goal, then keep retrying
2222  *   upto a max of sbi->s_mb_max_to_scan times (default 200). After
2223  *   that stop scanning and use whatever we have.
2224  *
2225  * * If free extent found is bigger than goal, then keep retrying
2226  *   upto a max of sbi->s_mb_min_to_scan times (default 10) before
2227  *   stopping the scan and using the extent.
2228  *
2229  *
2230  * FIXME: real allocation policy is to be designed yet!
2231  */
ext4_mb_measure_extent(struct ext4_allocation_context * ac,struct ext4_free_extent * ex,struct ext4_buddy * e4b)2232 static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
2233 					struct ext4_free_extent *ex,
2234 					struct ext4_buddy *e4b)
2235 {
2236 	struct ext4_free_extent *bex = &ac->ac_b_ex;
2237 	struct ext4_free_extent *gex = &ac->ac_g_ex;
2238 
2239 	BUG_ON(ex->fe_len <= 0);
2240 	BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
2241 	BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
2242 	BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
2243 
2244 	ac->ac_found++;
2245 	ac->ac_cX_found[ac->ac_criteria]++;
2246 
2247 	/*
2248 	 * The special case - take what you catch first
2249 	 */
2250 	if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2251 		*bex = *ex;
2252 		ext4_mb_use_best_found(ac, e4b);
2253 		return;
2254 	}
2255 
2256 	/*
2257 	 * Let's check whether the chuck is good enough
2258 	 */
2259 	if (ex->fe_len == gex->fe_len) {
2260 		*bex = *ex;
2261 		ext4_mb_use_best_found(ac, e4b);
2262 		return;
2263 	}
2264 
2265 	/*
2266 	 * If this is first found extent, just store it in the context
2267 	 */
2268 	if (bex->fe_len == 0) {
2269 		*bex = *ex;
2270 		return;
2271 	}
2272 
2273 	/*
2274 	 * If new found extent is better, store it in the context
2275 	 */
2276 	if (bex->fe_len < gex->fe_len) {
2277 		/* if the request isn't satisfied, any found extent
2278 		 * larger than previous best one is better */
2279 		if (ex->fe_len > bex->fe_len)
2280 			*bex = *ex;
2281 	} else if (ex->fe_len > gex->fe_len) {
2282 		/* if the request is satisfied, then we try to find
2283 		 * an extent that still satisfy the request, but is
2284 		 * smaller than previous one */
2285 		if (ex->fe_len < bex->fe_len)
2286 			*bex = *ex;
2287 	}
2288 
2289 	ext4_mb_check_limits(ac, e4b, 0);
2290 }
2291 
2292 static noinline_for_stack
ext4_mb_try_best_found(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)2293 void ext4_mb_try_best_found(struct ext4_allocation_context *ac,
2294 					struct ext4_buddy *e4b)
2295 {
2296 	struct ext4_free_extent ex = ac->ac_b_ex;
2297 	ext4_group_t group = ex.fe_group;
2298 	int max;
2299 	int err;
2300 
2301 	BUG_ON(ex.fe_len <= 0);
2302 	err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
2303 	if (err)
2304 		return;
2305 
2306 	ext4_lock_group(ac->ac_sb, group);
2307 	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
2308 		goto out;
2309 
2310 	max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
2311 
2312 	if (max > 0) {
2313 		ac->ac_b_ex = ex;
2314 		ext4_mb_use_best_found(ac, e4b);
2315 	}
2316 
2317 out:
2318 	ext4_unlock_group(ac->ac_sb, group);
2319 	ext4_mb_unload_buddy(e4b);
2320 }
2321 
2322 static noinline_for_stack
ext4_mb_find_by_goal(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)2323 int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
2324 				struct ext4_buddy *e4b)
2325 {
2326 	ext4_group_t group = ac->ac_g_ex.fe_group;
2327 	int max;
2328 	int err;
2329 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
2330 	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
2331 	struct ext4_free_extent ex;
2332 
2333 	if (!grp)
2334 		return -EFSCORRUPTED;
2335 	if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY)))
2336 		return 0;
2337 	if (grp->bb_free == 0)
2338 		return 0;
2339 
2340 	err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
2341 	if (err)
2342 		return err;
2343 
2344 	ext4_lock_group(ac->ac_sb, group);
2345 	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
2346 		goto out;
2347 
2348 	max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
2349 			     ac->ac_g_ex.fe_len, &ex);
2350 	ex.fe_logical = 0xDEADFA11; /* debug value */
2351 
2352 	if (max >= ac->ac_g_ex.fe_len &&
2353 	    ac->ac_g_ex.fe_len == EXT4_B2C(sbi, sbi->s_stripe)) {
2354 		ext4_fsblk_t start;
2355 
2356 		start = ext4_grp_offs_to_block(ac->ac_sb, &ex);
2357 		/* use do_div to get remainder (would be 64-bit modulo) */
2358 		if (do_div(start, sbi->s_stripe) == 0) {
2359 			ac->ac_found++;
2360 			ac->ac_b_ex = ex;
2361 			ext4_mb_use_best_found(ac, e4b);
2362 		}
2363 	} else if (max >= ac->ac_g_ex.fe_len) {
2364 		BUG_ON(ex.fe_len <= 0);
2365 		BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
2366 		BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
2367 		ac->ac_found++;
2368 		ac->ac_b_ex = ex;
2369 		ext4_mb_use_best_found(ac, e4b);
2370 	} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
2371 		/* Sometimes, caller may want to merge even small
2372 		 * number of blocks to an existing extent */
2373 		BUG_ON(ex.fe_len <= 0);
2374 		BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
2375 		BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
2376 		ac->ac_found++;
2377 		ac->ac_b_ex = ex;
2378 		ext4_mb_use_best_found(ac, e4b);
2379 	}
2380 out:
2381 	ext4_unlock_group(ac->ac_sb, group);
2382 	ext4_mb_unload_buddy(e4b);
2383 
2384 	return 0;
2385 }
2386 
2387 /*
2388  * The routine scans buddy structures (not bitmap!) from given order
2389  * to max order and tries to find big enough chunk to satisfy the req
2390  */
2391 static noinline_for_stack
ext4_mb_simple_scan_group(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)2392 void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
2393 					struct ext4_buddy *e4b)
2394 {
2395 	struct super_block *sb = ac->ac_sb;
2396 	struct ext4_group_info *grp = e4b->bd_info;
2397 	void *buddy;
2398 	int i;
2399 	int k;
2400 	int max;
2401 
2402 	BUG_ON(ac->ac_2order <= 0);
2403 	for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) {
2404 		if (grp->bb_counters[i] == 0)
2405 			continue;
2406 
2407 		buddy = mb_find_buddy(e4b, i, &max);
2408 		if (WARN_RATELIMIT(buddy == NULL,
2409 			 "ext4: mb_simple_scan_group: mb_find_buddy failed, (%d)\n", i))
2410 			continue;
2411 
2412 		k = mb_find_next_zero_bit(buddy, max, 0);
2413 		if (k >= max) {
2414 			ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0,
2415 				"%d free clusters of order %d. But found 0",
2416 				grp->bb_counters[i], i);
2417 			ext4_mark_group_bitmap_corrupted(ac->ac_sb,
2418 					 e4b->bd_group,
2419 					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
2420 			break;
2421 		}
2422 		ac->ac_found++;
2423 		ac->ac_cX_found[ac->ac_criteria]++;
2424 
2425 		ac->ac_b_ex.fe_len = 1 << i;
2426 		ac->ac_b_ex.fe_start = k << i;
2427 		ac->ac_b_ex.fe_group = e4b->bd_group;
2428 
2429 		ext4_mb_use_best_found(ac, e4b);
2430 
2431 		BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len);
2432 
2433 		if (EXT4_SB(sb)->s_mb_stats)
2434 			atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
2435 
2436 		break;
2437 	}
2438 }
2439 
2440 /*
2441  * The routine scans the group and measures all found extents.
2442  * In order to optimize scanning, caller must pass number of
2443  * free blocks in the group, so the routine can know upper limit.
2444  */
2445 static noinline_for_stack
ext4_mb_complex_scan_group(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)2446 void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
2447 					struct ext4_buddy *e4b)
2448 {
2449 	struct super_block *sb = ac->ac_sb;
2450 	void *bitmap = e4b->bd_bitmap;
2451 	struct ext4_free_extent ex;
2452 	int i, j, freelen;
2453 	int free;
2454 
2455 	free = e4b->bd_info->bb_free;
2456 	if (WARN_ON(free <= 0))
2457 		return;
2458 
2459 	i = e4b->bd_info->bb_first_free;
2460 
2461 	while (free && ac->ac_status == AC_STATUS_CONTINUE) {
2462 		i = mb_find_next_zero_bit(bitmap,
2463 						EXT4_CLUSTERS_PER_GROUP(sb), i);
2464 		if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
2465 			/*
2466 			 * IF we have corrupt bitmap, we won't find any
2467 			 * free blocks even though group info says we
2468 			 * have free blocks
2469 			 */
2470 			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
2471 					"%d free clusters as per "
2472 					"group info. But bitmap says 0",
2473 					free);
2474 			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
2475 					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
2476 			break;
2477 		}
2478 
2479 		if (!ext4_mb_cr_expensive(ac->ac_criteria)) {
2480 			/*
2481 			 * In CR_GOAL_LEN_FAST and CR_BEST_AVAIL_LEN, we are
2482 			 * sure that this group will have a large enough
2483 			 * continuous free extent, so skip over the smaller free
2484 			 * extents
2485 			 */
2486 			j = mb_find_next_bit(bitmap,
2487 						EXT4_CLUSTERS_PER_GROUP(sb), i);
2488 			freelen = j - i;
2489 
2490 			if (freelen < ac->ac_g_ex.fe_len) {
2491 				i = j;
2492 				free -= freelen;
2493 				continue;
2494 			}
2495 		}
2496 
2497 		mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
2498 		if (WARN_ON(ex.fe_len <= 0))
2499 			break;
2500 		if (free < ex.fe_len) {
2501 			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
2502 					"%d free clusters as per "
2503 					"group info. But got %d blocks",
2504 					free, ex.fe_len);
2505 			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
2506 					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
2507 			/*
2508 			 * The number of free blocks differs. This mostly
2509 			 * indicate that the bitmap is corrupt. So exit
2510 			 * without claiming the space.
2511 			 */
2512 			break;
2513 		}
2514 		ex.fe_logical = 0xDEADC0DE; /* debug value */
2515 		ext4_mb_measure_extent(ac, &ex, e4b);
2516 
2517 		i += ex.fe_len;
2518 		free -= ex.fe_len;
2519 	}
2520 
2521 	ext4_mb_check_limits(ac, e4b, 1);
2522 }
2523 
2524 /*
2525  * This is a special case for storages like raid5
2526  * we try to find stripe-aligned chunks for stripe-size-multiple requests
2527  */
2528 static noinline_for_stack
ext4_mb_scan_aligned(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)2529 void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
2530 				 struct ext4_buddy *e4b)
2531 {
2532 	struct super_block *sb = ac->ac_sb;
2533 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2534 	void *bitmap = e4b->bd_bitmap;
2535 	struct ext4_free_extent ex;
2536 	ext4_fsblk_t first_group_block;
2537 	ext4_fsblk_t a;
2538 	ext4_grpblk_t i, stripe;
2539 	int max;
2540 
2541 	BUG_ON(sbi->s_stripe == 0);
2542 
2543 	/* find first stripe-aligned block in group */
2544 	first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
2545 
2546 	a = first_group_block + sbi->s_stripe - 1;
2547 	do_div(a, sbi->s_stripe);
2548 	i = (a * sbi->s_stripe) - first_group_block;
2549 
2550 	stripe = EXT4_B2C(sbi, sbi->s_stripe);
2551 	i = EXT4_B2C(sbi, i);
2552 	while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
2553 		if (!mb_test_bit(i, bitmap)) {
2554 			max = mb_find_extent(e4b, i, stripe, &ex);
2555 			if (max >= stripe) {
2556 				ac->ac_found++;
2557 				ac->ac_cX_found[ac->ac_criteria]++;
2558 				ex.fe_logical = 0xDEADF00D; /* debug value */
2559 				ac->ac_b_ex = ex;
2560 				ext4_mb_use_best_found(ac, e4b);
2561 				break;
2562 			}
2563 		}
2564 		i += stripe;
2565 	}
2566 }
2567 
2568 /*
2569  * This is also called BEFORE we load the buddy bitmap.
2570  * Returns either 1 or 0 indicating that the group is either suitable
2571  * for the allocation or not.
2572  */
ext4_mb_good_group(struct ext4_allocation_context * ac,ext4_group_t group,enum criteria cr)2573 static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
2574 				ext4_group_t group, enum criteria cr)
2575 {
2576 	ext4_grpblk_t free, fragments;
2577 	int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
2578 	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
2579 
2580 	BUG_ON(cr < CR_POWER2_ALIGNED || cr >= EXT4_MB_NUM_CRS);
2581 
2582 	if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
2583 		return false;
2584 
2585 	free = grp->bb_free;
2586 	if (free == 0)
2587 		return false;
2588 
2589 	fragments = grp->bb_fragments;
2590 	if (fragments == 0)
2591 		return false;
2592 
2593 	switch (cr) {
2594 	case CR_POWER2_ALIGNED:
2595 		BUG_ON(ac->ac_2order == 0);
2596 
2597 		/* Avoid using the first bg of a flexgroup for data files */
2598 		if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
2599 		    (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
2600 		    ((group % flex_size) == 0))
2601 			return false;
2602 
2603 		if (free < ac->ac_g_ex.fe_len)
2604 			return false;
2605 
2606 		if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb))
2607 			return true;
2608 
2609 		if (grp->bb_largest_free_order < ac->ac_2order)
2610 			return false;
2611 
2612 		return true;
2613 	case CR_GOAL_LEN_FAST:
2614 	case CR_BEST_AVAIL_LEN:
2615 		if ((free / fragments) >= ac->ac_g_ex.fe_len)
2616 			return true;
2617 		break;
2618 	case CR_GOAL_LEN_SLOW:
2619 		if (free >= ac->ac_g_ex.fe_len)
2620 			return true;
2621 		break;
2622 	case CR_ANY_FREE:
2623 		return true;
2624 	default:
2625 		BUG();
2626 	}
2627 
2628 	return false;
2629 }
2630 
2631 /*
2632  * This could return negative error code if something goes wrong
2633  * during ext4_mb_init_group(). This should not be called with
2634  * ext4_lock_group() held.
2635  *
2636  * Note: because we are conditionally operating with the group lock in
2637  * the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this
2638  * function using __acquire and __release.  This means we need to be
2639  * super careful before messing with the error path handling via "goto
2640  * out"!
2641  */
ext4_mb_good_group_nolock(struct ext4_allocation_context * ac,ext4_group_t group,enum criteria cr)2642 static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
2643 				     ext4_group_t group, enum criteria cr)
2644 {
2645 	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
2646 	struct super_block *sb = ac->ac_sb;
2647 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2648 	bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK;
2649 	ext4_grpblk_t free;
2650 	int ret = 0;
2651 
2652 	if (!grp)
2653 		return -EFSCORRUPTED;
2654 	if (sbi->s_mb_stats)
2655 		atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
2656 	if (should_lock) {
2657 		ext4_lock_group(sb, group);
2658 		__release(ext4_group_lock_ptr(sb, group));
2659 	}
2660 	free = grp->bb_free;
2661 	if (free == 0)
2662 		goto out;
2663 	/*
2664 	 * In all criterias except CR_ANY_FREE we try to avoid groups that
2665 	 * can't possibly satisfy the full goal request due to insufficient
2666 	 * free blocks.
2667 	 */
2668 	if (cr < CR_ANY_FREE && free < ac->ac_g_ex.fe_len)
2669 		goto out;
2670 	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
2671 		goto out;
2672 	if (should_lock) {
2673 		__acquire(ext4_group_lock_ptr(sb, group));
2674 		ext4_unlock_group(sb, group);
2675 	}
2676 
2677 	/* We only do this if the grp has never been initialized */
2678 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
2679 		struct ext4_group_desc *gdp =
2680 			ext4_get_group_desc(sb, group, NULL);
2681 		int ret;
2682 
2683 		/*
2684 		 * cr=CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic
2685 		 * search to find large good chunks almost for free. If buddy
2686 		 * data is not ready, then this optimization makes no sense. But
2687 		 * we never skip the first block group in a flex_bg, since this
2688 		 * gets used for metadata block allocation, and we want to make
2689 		 * sure we locate metadata blocks in the first block group in
2690 		 * the flex_bg if possible.
2691 		 */
2692 		if (!ext4_mb_cr_expensive(cr) &&
2693 		    (!sbi->s_log_groups_per_flex ||
2694 		     ((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) &&
2695 		    !(ext4_has_group_desc_csum(sb) &&
2696 		      (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))))
2697 			return 0;
2698 		ret = ext4_mb_init_group(sb, group, GFP_NOFS);
2699 		if (ret)
2700 			return ret;
2701 	}
2702 
2703 	if (should_lock) {
2704 		ext4_lock_group(sb, group);
2705 		__release(ext4_group_lock_ptr(sb, group));
2706 	}
2707 	ret = ext4_mb_good_group(ac, group, cr);
2708 out:
2709 	if (should_lock) {
2710 		__acquire(ext4_group_lock_ptr(sb, group));
2711 		ext4_unlock_group(sb, group);
2712 	}
2713 	return ret;
2714 }
2715 
2716 /*
2717  * Start prefetching @nr block bitmaps starting at @group.
2718  * Return the next group which needs to be prefetched.
2719  */
ext4_mb_prefetch(struct super_block * sb,ext4_group_t group,unsigned int nr,int * cnt)2720 ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
2721 			      unsigned int nr, int *cnt)
2722 {
2723 	ext4_group_t ngroups = ext4_get_groups_count(sb);
2724 	struct buffer_head *bh;
2725 	struct blk_plug plug;
2726 
2727 	blk_start_plug(&plug);
2728 	while (nr-- > 0) {
2729 		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
2730 								  NULL);
2731 		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
2732 
2733 		/*
2734 		 * Prefetch block groups with free blocks; but don't
2735 		 * bother if it is marked uninitialized on disk, since
2736 		 * it won't require I/O to read.  Also only try to
2737 		 * prefetch once, so we avoid getblk() call, which can
2738 		 * be expensive.
2739 		 */
2740 		if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
2741 		    EXT4_MB_GRP_NEED_INIT(grp) &&
2742 		    ext4_free_group_clusters(sb, gdp) > 0 ) {
2743 			bh = ext4_read_block_bitmap_nowait(sb, group, true);
2744 			if (bh && !IS_ERR(bh)) {
2745 				if (!buffer_uptodate(bh) && cnt)
2746 					(*cnt)++;
2747 				brelse(bh);
2748 			}
2749 		}
2750 		if (++group >= ngroups)
2751 			group = 0;
2752 	}
2753 	blk_finish_plug(&plug);
2754 	return group;
2755 }
2756 
2757 /*
2758  * Prefetching reads the block bitmap into the buffer cache; but we
2759  * need to make sure that the buddy bitmap in the page cache has been
2760  * initialized.  Note that ext4_mb_init_group() will block if the I/O
2761  * is not yet completed, or indeed if it was not initiated by
2762  * ext4_mb_prefetch did not start the I/O.
2763  *
2764  * TODO: We should actually kick off the buddy bitmap setup in a work
2765  * queue when the buffer I/O is completed, so that we don't block
2766  * waiting for the block allocation bitmap read to finish when
2767  * ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator().
2768  */
ext4_mb_prefetch_fini(struct super_block * sb,ext4_group_t group,unsigned int nr)2769 void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
2770 			   unsigned int nr)
2771 {
2772 	struct ext4_group_desc *gdp;
2773 	struct ext4_group_info *grp;
2774 
2775 	while (nr-- > 0) {
2776 		if (!group)
2777 			group = ext4_get_groups_count(sb);
2778 		group--;
2779 		gdp = ext4_get_group_desc(sb, group, NULL);
2780 		grp = ext4_get_group_info(sb, group);
2781 
2782 		if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) &&
2783 		    ext4_free_group_clusters(sb, gdp) > 0) {
2784 			if (ext4_mb_init_group(sb, group, GFP_NOFS))
2785 				break;
2786 		}
2787 	}
2788 }
2789 
2790 static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context * ac)2791 ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
2792 {
2793 	ext4_group_t prefetch_grp = 0, ngroups, group, i;
2794 	enum criteria new_cr, cr = CR_GOAL_LEN_FAST;
2795 	int err = 0, first_err = 0;
2796 	unsigned int nr = 0, prefetch_ios = 0;
2797 	struct ext4_sb_info *sbi;
2798 	struct super_block *sb;
2799 	struct ext4_buddy e4b;
2800 	int lost;
2801 
2802 	sb = ac->ac_sb;
2803 	sbi = EXT4_SB(sb);
2804 	ngroups = ext4_get_groups_count(sb);
2805 	/* non-extent files are limited to low blocks/groups */
2806 	if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
2807 		ngroups = sbi->s_blockfile_groups;
2808 
2809 	BUG_ON(ac->ac_status == AC_STATUS_FOUND);
2810 
2811 	/* first, try the goal */
2812 	err = ext4_mb_find_by_goal(ac, &e4b);
2813 	if (err || ac->ac_status == AC_STATUS_FOUND)
2814 		goto out;
2815 
2816 	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
2817 		goto out;
2818 
2819 	/*
2820 	 * ac->ac_2order is set only if the fe_len is a power of 2
2821 	 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
2822 	 * so that we try exact allocation using buddy.
2823 	 */
2824 	i = fls(ac->ac_g_ex.fe_len);
2825 	ac->ac_2order = 0;
2826 	/*
2827 	 * We search using buddy data only if the order of the request
2828 	 * is greater than equal to the sbi_s_mb_order2_reqs
2829 	 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
2830 	 * We also support searching for power-of-two requests only for
2831 	 * requests upto maximum buddy size we have constructed.
2832 	 */
2833 	if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) {
2834 		if (is_power_of_2(ac->ac_g_ex.fe_len))
2835 			ac->ac_2order = array_index_nospec(i - 1,
2836 							   MB_NUM_ORDERS(sb));
2837 	}
2838 
2839 	/* if stream allocation is enabled, use global goal */
2840 	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
2841 		/* TBD: may be hot point */
2842 		spin_lock(&sbi->s_md_lock);
2843 		ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
2844 		ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
2845 		spin_unlock(&sbi->s_md_lock);
2846 	}
2847 
2848 	/*
2849 	 * Let's just scan groups to find more-less suitable blocks We
2850 	 * start with CR_GOAL_LEN_FAST, unless it is power of 2
2851 	 * aligned, in which case let's do that faster approach first.
2852 	 */
2853 	if (ac->ac_2order)
2854 		cr = CR_POWER2_ALIGNED;
2855 repeat:
2856 	for (; cr < EXT4_MB_NUM_CRS && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
2857 		ac->ac_criteria = cr;
2858 		/*
2859 		 * searching for the right group start
2860 		 * from the goal value specified
2861 		 */
2862 		group = ac->ac_g_ex.fe_group;
2863 		ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups;
2864 		prefetch_grp = group;
2865 
2866 		for (i = 0, new_cr = cr; i < ngroups; i++,
2867 		     ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) {
2868 			int ret = 0;
2869 
2870 			cond_resched();
2871 			if (new_cr != cr) {
2872 				cr = new_cr;
2873 				goto repeat;
2874 			}
2875 
2876 			/*
2877 			 * Batch reads of the block allocation bitmaps
2878 			 * to get multiple READs in flight; limit
2879 			 * prefetching at inexpensive CR, otherwise mballoc
2880 			 * can spend a lot of time loading imperfect groups
2881 			 */
2882 			if ((prefetch_grp == group) &&
2883 			    (ext4_mb_cr_expensive(cr) ||
2884 			     prefetch_ios < sbi->s_mb_prefetch_limit)) {
2885 				nr = sbi->s_mb_prefetch;
2886 				if (ext4_has_feature_flex_bg(sb)) {
2887 					nr = 1 << sbi->s_log_groups_per_flex;
2888 					nr -= group & (nr - 1);
2889 					nr = min(nr, sbi->s_mb_prefetch);
2890 				}
2891 				prefetch_grp = ext4_mb_prefetch(sb, group,
2892 							nr, &prefetch_ios);
2893 			}
2894 
2895 			/* This now checks without needing the buddy page */
2896 			ret = ext4_mb_good_group_nolock(ac, group, cr);
2897 			if (ret <= 0) {
2898 				if (!first_err)
2899 					first_err = ret;
2900 				continue;
2901 			}
2902 
2903 			err = ext4_mb_load_buddy(sb, group, &e4b);
2904 			if (err)
2905 				goto out;
2906 
2907 			ext4_lock_group(sb, group);
2908 
2909 			/*
2910 			 * We need to check again after locking the
2911 			 * block group
2912 			 */
2913 			ret = ext4_mb_good_group(ac, group, cr);
2914 			if (ret == 0) {
2915 				ext4_unlock_group(sb, group);
2916 				ext4_mb_unload_buddy(&e4b);
2917 				continue;
2918 			}
2919 
2920 			ac->ac_groups_scanned++;
2921 			if (cr == CR_POWER2_ALIGNED)
2922 				ext4_mb_simple_scan_group(ac, &e4b);
2923 			else if ((cr == CR_GOAL_LEN_FAST ||
2924 				 cr == CR_BEST_AVAIL_LEN) &&
2925 				 sbi->s_stripe &&
2926 				 !(ac->ac_g_ex.fe_len %
2927 				 EXT4_B2C(sbi, sbi->s_stripe)))
2928 				ext4_mb_scan_aligned(ac, &e4b);
2929 			else
2930 				ext4_mb_complex_scan_group(ac, &e4b);
2931 
2932 			ext4_unlock_group(sb, group);
2933 			ext4_mb_unload_buddy(&e4b);
2934 
2935 			if (ac->ac_status != AC_STATUS_CONTINUE)
2936 				break;
2937 		}
2938 		/* Processed all groups and haven't found blocks */
2939 		if (sbi->s_mb_stats && i == ngroups)
2940 			atomic64_inc(&sbi->s_bal_cX_failed[cr]);
2941 
2942 		if (i == ngroups && ac->ac_criteria == CR_BEST_AVAIL_LEN)
2943 			/* Reset goal length to original goal length before
2944 			 * falling into CR_GOAL_LEN_SLOW */
2945 			ac->ac_g_ex.fe_len = ac->ac_orig_goal_len;
2946 	}
2947 
2948 	if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
2949 	    !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2950 		/*
2951 		 * We've been searching too long. Let's try to allocate
2952 		 * the best chunk we've found so far
2953 		 */
2954 		ext4_mb_try_best_found(ac, &e4b);
2955 		if (ac->ac_status != AC_STATUS_FOUND) {
2956 			/*
2957 			 * Someone more lucky has already allocated it.
2958 			 * The only thing we can do is just take first
2959 			 * found block(s)
2960 			 */
2961 			lost = atomic_inc_return(&sbi->s_mb_lost_chunks);
2962 			mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n",
2963 				 ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start,
2964 				 ac->ac_b_ex.fe_len, lost);
2965 
2966 			ac->ac_b_ex.fe_group = 0;
2967 			ac->ac_b_ex.fe_start = 0;
2968 			ac->ac_b_ex.fe_len = 0;
2969 			ac->ac_status = AC_STATUS_CONTINUE;
2970 			ac->ac_flags |= EXT4_MB_HINT_FIRST;
2971 			cr = CR_ANY_FREE;
2972 			goto repeat;
2973 		}
2974 	}
2975 
2976 	if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND)
2977 		atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
2978 out:
2979 	if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
2980 		err = first_err;
2981 
2982 	mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
2983 		 ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
2984 		 ac->ac_flags, cr, err);
2985 
2986 	if (nr)
2987 		ext4_mb_prefetch_fini(sb, prefetch_grp, nr);
2988 
2989 	return err;
2990 }
2991 
ext4_mb_seq_groups_start(struct seq_file * seq,loff_t * pos)2992 static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
2993 {
2994 	struct super_block *sb = pde_data(file_inode(seq->file));
2995 	ext4_group_t group;
2996 
2997 	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2998 		return NULL;
2999 	group = *pos + 1;
3000 	return (void *) ((unsigned long) group);
3001 }
3002 
ext4_mb_seq_groups_next(struct seq_file * seq,void * v,loff_t * pos)3003 static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
3004 {
3005 	struct super_block *sb = pde_data(file_inode(seq->file));
3006 	ext4_group_t group;
3007 
3008 	++*pos;
3009 	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
3010 		return NULL;
3011 	group = *pos + 1;
3012 	return (void *) ((unsigned long) group);
3013 }
3014 
ext4_mb_seq_groups_show(struct seq_file * seq,void * v)3015 static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
3016 {
3017 	struct super_block *sb = pde_data(file_inode(seq->file));
3018 	ext4_group_t group = (ext4_group_t) ((unsigned long) v);
3019 	int i;
3020 	int err, buddy_loaded = 0;
3021 	struct ext4_buddy e4b;
3022 	struct ext4_group_info *grinfo;
3023 	unsigned char blocksize_bits = min_t(unsigned char,
3024 					     sb->s_blocksize_bits,
3025 					     EXT4_MAX_BLOCK_LOG_SIZE);
3026 	struct sg {
3027 		struct ext4_group_info info;
3028 		ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];
3029 	} sg;
3030 
3031 	group--;
3032 	if (group == 0)
3033 		seq_puts(seq, "#group: free  frags first ["
3034 			      " 2^0   2^1   2^2   2^3   2^4   2^5   2^6  "
3035 			      " 2^7   2^8   2^9   2^10  2^11  2^12  2^13  ]\n");
3036 
3037 	i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
3038 		sizeof(struct ext4_group_info);
3039 
3040 	grinfo = ext4_get_group_info(sb, group);
3041 	if (!grinfo)
3042 		return 0;
3043 	/* Load the group info in memory only if not already loaded. */
3044 	if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
3045 		err = ext4_mb_load_buddy(sb, group, &e4b);
3046 		if (err) {
3047 			seq_printf(seq, "#%-5u: I/O error\n", group);
3048 			return 0;
3049 		}
3050 		buddy_loaded = 1;
3051 	}
3052 
3053 	memcpy(&sg, grinfo, i);
3054 
3055 	if (buddy_loaded)
3056 		ext4_mb_unload_buddy(&e4b);
3057 
3058 	seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
3059 			sg.info.bb_fragments, sg.info.bb_first_free);
3060 	for (i = 0; i <= 13; i++)
3061 		seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ?
3062 				sg.info.bb_counters[i] : 0);
3063 	seq_puts(seq, " ]\n");
3064 
3065 	return 0;
3066 }
3067 
ext4_mb_seq_groups_stop(struct seq_file * seq,void * v)3068 static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
3069 {
3070 }
3071 
3072 const struct seq_operations ext4_mb_seq_groups_ops = {
3073 	.start  = ext4_mb_seq_groups_start,
3074 	.next   = ext4_mb_seq_groups_next,
3075 	.stop   = ext4_mb_seq_groups_stop,
3076 	.show   = ext4_mb_seq_groups_show,
3077 };
3078 
ext4_seq_mb_stats_show(struct seq_file * seq,void * offset)3079 int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
3080 {
3081 	struct super_block *sb = seq->private;
3082 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3083 
3084 	seq_puts(seq, "mballoc:\n");
3085 	if (!sbi->s_mb_stats) {
3086 		seq_puts(seq, "\tmb stats collection turned off.\n");
3087 		seq_puts(
3088 			seq,
3089 			"\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
3090 		return 0;
3091 	}
3092 	seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
3093 	seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
3094 
3095 	seq_printf(seq, "\tgroups_scanned: %u\n",
3096 		   atomic_read(&sbi->s_bal_groups_scanned));
3097 
3098 	/* CR_POWER2_ALIGNED stats */
3099 	seq_puts(seq, "\tcr_p2_aligned_stats:\n");
3100 	seq_printf(seq, "\t\thits: %llu\n",
3101 		   atomic64_read(&sbi->s_bal_cX_hits[CR_POWER2_ALIGNED]));
3102 	seq_printf(
3103 		seq, "\t\tgroups_considered: %llu\n",
3104 		atomic64_read(
3105 			&sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]));
3106 	seq_printf(seq, "\t\textents_scanned: %u\n",
3107 		   atomic_read(&sbi->s_bal_cX_ex_scanned[CR_POWER2_ALIGNED]));
3108 	seq_printf(seq, "\t\tuseless_loops: %llu\n",
3109 		   atomic64_read(&sbi->s_bal_cX_failed[CR_POWER2_ALIGNED]));
3110 	seq_printf(seq, "\t\tbad_suggestions: %u\n",
3111 		   atomic_read(&sbi->s_bal_p2_aligned_bad_suggestions));
3112 
3113 	/* CR_GOAL_LEN_FAST stats */
3114 	seq_puts(seq, "\tcr_goal_fast_stats:\n");
3115 	seq_printf(seq, "\t\thits: %llu\n",
3116 		   atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_FAST]));
3117 	seq_printf(seq, "\t\tgroups_considered: %llu\n",
3118 		   atomic64_read(
3119 			   &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_FAST]));
3120 	seq_printf(seq, "\t\textents_scanned: %u\n",
3121 		   atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_FAST]));
3122 	seq_printf(seq, "\t\tuseless_loops: %llu\n",
3123 		   atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_FAST]));
3124 	seq_printf(seq, "\t\tbad_suggestions: %u\n",
3125 		   atomic_read(&sbi->s_bal_goal_fast_bad_suggestions));
3126 
3127 	/* CR_BEST_AVAIL_LEN stats */
3128 	seq_puts(seq, "\tcr_best_avail_stats:\n");
3129 	seq_printf(seq, "\t\thits: %llu\n",
3130 		   atomic64_read(&sbi->s_bal_cX_hits[CR_BEST_AVAIL_LEN]));
3131 	seq_printf(
3132 		seq, "\t\tgroups_considered: %llu\n",
3133 		atomic64_read(
3134 			&sbi->s_bal_cX_groups_considered[CR_BEST_AVAIL_LEN]));
3135 	seq_printf(seq, "\t\textents_scanned: %u\n",
3136 		   atomic_read(&sbi->s_bal_cX_ex_scanned[CR_BEST_AVAIL_LEN]));
3137 	seq_printf(seq, "\t\tuseless_loops: %llu\n",
3138 		   atomic64_read(&sbi->s_bal_cX_failed[CR_BEST_AVAIL_LEN]));
3139 	seq_printf(seq, "\t\tbad_suggestions: %u\n",
3140 		   atomic_read(&sbi->s_bal_best_avail_bad_suggestions));
3141 
3142 	/* CR_GOAL_LEN_SLOW stats */
3143 	seq_puts(seq, "\tcr_goal_slow_stats:\n");
3144 	seq_printf(seq, "\t\thits: %llu\n",
3145 		   atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_SLOW]));
3146 	seq_printf(seq, "\t\tgroups_considered: %llu\n",
3147 		   atomic64_read(
3148 			   &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_SLOW]));
3149 	seq_printf(seq, "\t\textents_scanned: %u\n",
3150 		   atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_SLOW]));
3151 	seq_printf(seq, "\t\tuseless_loops: %llu\n",
3152 		   atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_SLOW]));
3153 
3154 	/* CR_ANY_FREE stats */
3155 	seq_puts(seq, "\tcr_any_free_stats:\n");
3156 	seq_printf(seq, "\t\thits: %llu\n",
3157 		   atomic64_read(&sbi->s_bal_cX_hits[CR_ANY_FREE]));
3158 	seq_printf(
3159 		seq, "\t\tgroups_considered: %llu\n",
3160 		atomic64_read(&sbi->s_bal_cX_groups_considered[CR_ANY_FREE]));
3161 	seq_printf(seq, "\t\textents_scanned: %u\n",
3162 		   atomic_read(&sbi->s_bal_cX_ex_scanned[CR_ANY_FREE]));
3163 	seq_printf(seq, "\t\tuseless_loops: %llu\n",
3164 		   atomic64_read(&sbi->s_bal_cX_failed[CR_ANY_FREE]));
3165 
3166 	/* Aggregates */
3167 	seq_printf(seq, "\textents_scanned: %u\n",
3168 		   atomic_read(&sbi->s_bal_ex_scanned));
3169 	seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
3170 	seq_printf(seq, "\t\tlen_goal_hits: %u\n",
3171 		   atomic_read(&sbi->s_bal_len_goals));
3172 	seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
3173 	seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
3174 	seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
3175 	seq_printf(seq, "\tbuddies_generated: %u/%u\n",
3176 		   atomic_read(&sbi->s_mb_buddies_generated),
3177 		   ext4_get_groups_count(sb));
3178 	seq_printf(seq, "\tbuddies_time_used: %llu\n",
3179 		   atomic64_read(&sbi->s_mb_generation_time));
3180 	seq_printf(seq, "\tpreallocated: %u\n",
3181 		   atomic_read(&sbi->s_mb_preallocated));
3182 	seq_printf(seq, "\tdiscarded: %u\n", atomic_read(&sbi->s_mb_discarded));
3183 	return 0;
3184 }
3185 
ext4_mb_seq_structs_summary_start(struct seq_file * seq,loff_t * pos)3186 static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos)
3187 __acquires(&EXT4_SB(sb)->s_mb_rb_lock)
3188 {
3189 	struct super_block *sb = pde_data(file_inode(seq->file));
3190 	unsigned long position;
3191 
3192 	if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb))
3193 		return NULL;
3194 	position = *pos + 1;
3195 	return (void *) ((unsigned long) position);
3196 }
3197 
ext4_mb_seq_structs_summary_next(struct seq_file * seq,void * v,loff_t * pos)3198 static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos)
3199 {
3200 	struct super_block *sb = pde_data(file_inode(seq->file));
3201 	unsigned long position;
3202 
3203 	++*pos;
3204 	if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb))
3205 		return NULL;
3206 	position = *pos + 1;
3207 	return (void *) ((unsigned long) position);
3208 }
3209 
ext4_mb_seq_structs_summary_show(struct seq_file * seq,void * v)3210 static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v)
3211 {
3212 	struct super_block *sb = pde_data(file_inode(seq->file));
3213 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3214 	unsigned long position = ((unsigned long) v);
3215 	struct ext4_group_info *grp;
3216 	unsigned int count;
3217 
3218 	position--;
3219 	if (position >= MB_NUM_ORDERS(sb)) {
3220 		position -= MB_NUM_ORDERS(sb);
3221 		if (position == 0)
3222 			seq_puts(seq, "avg_fragment_size_lists:\n");
3223 
3224 		count = 0;
3225 		read_lock(&sbi->s_mb_avg_fragment_size_locks[position]);
3226 		list_for_each_entry(grp, &sbi->s_mb_avg_fragment_size[position],
3227 				    bb_avg_fragment_size_node)
3228 			count++;
3229 		read_unlock(&sbi->s_mb_avg_fragment_size_locks[position]);
3230 		seq_printf(seq, "\tlist_order_%u_groups: %u\n",
3231 					(unsigned int)position, count);
3232 		return 0;
3233 	}
3234 
3235 	if (position == 0) {
3236 		seq_printf(seq, "optimize_scan: %d\n",
3237 			   test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0);
3238 		seq_puts(seq, "max_free_order_lists:\n");
3239 	}
3240 	count = 0;
3241 	read_lock(&sbi->s_mb_largest_free_orders_locks[position]);
3242 	list_for_each_entry(grp, &sbi->s_mb_largest_free_orders[position],
3243 			    bb_largest_free_order_node)
3244 		count++;
3245 	read_unlock(&sbi->s_mb_largest_free_orders_locks[position]);
3246 	seq_printf(seq, "\tlist_order_%u_groups: %u\n",
3247 		   (unsigned int)position, count);
3248 
3249 	return 0;
3250 }
3251 
ext4_mb_seq_structs_summary_stop(struct seq_file * seq,void * v)3252 static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v)
3253 {
3254 }
3255 
3256 const struct seq_operations ext4_mb_seq_structs_summary_ops = {
3257 	.start  = ext4_mb_seq_structs_summary_start,
3258 	.next   = ext4_mb_seq_structs_summary_next,
3259 	.stop   = ext4_mb_seq_structs_summary_stop,
3260 	.show   = ext4_mb_seq_structs_summary_show,
3261 };
3262 
get_groupinfo_cache(int blocksize_bits)3263 static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
3264 {
3265 	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
3266 	struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
3267 
3268 	BUG_ON(!cachep);
3269 	return cachep;
3270 }
3271 
3272 /*
3273  * Allocate the top-level s_group_info array for the specified number
3274  * of groups
3275  */
ext4_mb_alloc_groupinfo(struct super_block * sb,ext4_group_t ngroups)3276 int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
3277 {
3278 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3279 	unsigned size;
3280 	struct ext4_group_info ***old_groupinfo, ***new_groupinfo;
3281 
3282 	size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
3283 		EXT4_DESC_PER_BLOCK_BITS(sb);
3284 	if (size <= sbi->s_group_info_size)
3285 		return 0;
3286 
3287 	size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
3288 	new_groupinfo = kvzalloc(size, GFP_KERNEL);
3289 	if (!new_groupinfo) {
3290 		ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
3291 		return -ENOMEM;
3292 	}
3293 	rcu_read_lock();
3294 	old_groupinfo = rcu_dereference(sbi->s_group_info);
3295 	if (old_groupinfo)
3296 		memcpy(new_groupinfo, old_groupinfo,
3297 		       sbi->s_group_info_size * sizeof(*sbi->s_group_info));
3298 	rcu_read_unlock();
3299 	rcu_assign_pointer(sbi->s_group_info, new_groupinfo);
3300 	sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
3301 	if (old_groupinfo)
3302 		ext4_kvfree_array_rcu(old_groupinfo);
3303 	ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
3304 		   sbi->s_group_info_size);
3305 	return 0;
3306 }
3307 
3308 /* Create and initialize ext4_group_info data for the given group. */
ext4_mb_add_groupinfo(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * desc)3309 int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
3310 			  struct ext4_group_desc *desc)
3311 {
3312 	int i;
3313 	int metalen = 0;
3314 	int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb);
3315 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3316 	struct ext4_group_info **meta_group_info;
3317 	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
3318 
3319 	/*
3320 	 * First check if this group is the first of a reserved block.
3321 	 * If it's true, we have to allocate a new table of pointers
3322 	 * to ext4_group_info structures
3323 	 */
3324 	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
3325 		metalen = sizeof(*meta_group_info) <<
3326 			EXT4_DESC_PER_BLOCK_BITS(sb);
3327 		meta_group_info = kmalloc(metalen, GFP_NOFS);
3328 		if (meta_group_info == NULL) {
3329 			ext4_msg(sb, KERN_ERR, "can't allocate mem "
3330 				 "for a buddy group");
3331 			return -ENOMEM;
3332 		}
3333 		rcu_read_lock();
3334 		rcu_dereference(sbi->s_group_info)[idx] = meta_group_info;
3335 		rcu_read_unlock();
3336 	}
3337 
3338 	meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx);
3339 	i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
3340 
3341 	meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
3342 	if (meta_group_info[i] == NULL) {
3343 		ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
3344 		goto exit_group_info;
3345 	}
3346 	set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
3347 		&(meta_group_info[i]->bb_state));
3348 
3349 	/*
3350 	 * initialize bb_free to be able to skip
3351 	 * empty groups without initialization
3352 	 */
3353 	if (ext4_has_group_desc_csum(sb) &&
3354 	    (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
3355 		meta_group_info[i]->bb_free =
3356 			ext4_free_clusters_after_init(sb, group, desc);
3357 	} else {
3358 		meta_group_info[i]->bb_free =
3359 			ext4_free_group_clusters(sb, desc);
3360 	}
3361 
3362 	INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
3363 	init_rwsem(&meta_group_info[i]->alloc_sem);
3364 	meta_group_info[i]->bb_free_root = RB_ROOT;
3365 	INIT_LIST_HEAD(&meta_group_info[i]->bb_largest_free_order_node);
3366 	INIT_LIST_HEAD(&meta_group_info[i]->bb_avg_fragment_size_node);
3367 	meta_group_info[i]->bb_largest_free_order = -1;  /* uninit */
3368 	meta_group_info[i]->bb_avg_fragment_size_order = -1;  /* uninit */
3369 	meta_group_info[i]->bb_group = group;
3370 
3371 	mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group);
3372 	return 0;
3373 
3374 exit_group_info:
3375 	/* If a meta_group_info table has been allocated, release it now */
3376 	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
3377 		struct ext4_group_info ***group_info;
3378 
3379 		rcu_read_lock();
3380 		group_info = rcu_dereference(sbi->s_group_info);
3381 		kfree(group_info[idx]);
3382 		group_info[idx] = NULL;
3383 		rcu_read_unlock();
3384 	}
3385 	return -ENOMEM;
3386 } /* ext4_mb_add_groupinfo */
3387 
ext4_mb_init_backend(struct super_block * sb)3388 static int ext4_mb_init_backend(struct super_block *sb)
3389 {
3390 	ext4_group_t ngroups = ext4_get_groups_count(sb);
3391 	ext4_group_t i;
3392 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3393 	int err;
3394 	struct ext4_group_desc *desc;
3395 	struct ext4_group_info ***group_info;
3396 	struct kmem_cache *cachep;
3397 
3398 	err = ext4_mb_alloc_groupinfo(sb, ngroups);
3399 	if (err)
3400 		return err;
3401 
3402 	sbi->s_buddy_cache = new_inode(sb);
3403 	if (sbi->s_buddy_cache == NULL) {
3404 		ext4_msg(sb, KERN_ERR, "can't get new inode");
3405 		goto err_freesgi;
3406 	}
3407 	/* To avoid potentially colliding with an valid on-disk inode number,
3408 	 * use EXT4_BAD_INO for the buddy cache inode number.  This inode is
3409 	 * not in the inode hash, so it should never be found by iget(), but
3410 	 * this will avoid confusion if it ever shows up during debugging. */
3411 	sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
3412 	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
3413 	for (i = 0; i < ngroups; i++) {
3414 		cond_resched();
3415 		desc = ext4_get_group_desc(sb, i, NULL);
3416 		if (desc == NULL) {
3417 			ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
3418 			goto err_freebuddy;
3419 		}
3420 		if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
3421 			goto err_freebuddy;
3422 	}
3423 
3424 	if (ext4_has_feature_flex_bg(sb)) {
3425 		/* a single flex group is supposed to be read by a single IO.
3426 		 * 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is
3427 		 * unsigned integer, so the maximum shift is 32.
3428 		 */
3429 		if (sbi->s_es->s_log_groups_per_flex >= 32) {
3430 			ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group");
3431 			goto err_freebuddy;
3432 		}
3433 		sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex,
3434 			BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9));
3435 		sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */
3436 	} else {
3437 		sbi->s_mb_prefetch = 32;
3438 	}
3439 	if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))
3440 		sbi->s_mb_prefetch = ext4_get_groups_count(sb);
3441 	/* now many real IOs to prefetch within a single allocation at cr=0
3442 	 * given cr=0 is an CPU-related optimization we shouldn't try to
3443 	 * load too many groups, at some point we should start to use what
3444 	 * we've got in memory.
3445 	 * with an average random access time 5ms, it'd take a second to get
3446 	 * 200 groups (* N with flex_bg), so let's make this limit 4
3447 	 */
3448 	sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4;
3449 	if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb))
3450 		sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb);
3451 
3452 	return 0;
3453 
3454 err_freebuddy:
3455 	cachep = get_groupinfo_cache(sb->s_blocksize_bits);
3456 	while (i-- > 0) {
3457 		struct ext4_group_info *grp = ext4_get_group_info(sb, i);
3458 
3459 		if (grp)
3460 			kmem_cache_free(cachep, grp);
3461 	}
3462 	i = sbi->s_group_info_size;
3463 	rcu_read_lock();
3464 	group_info = rcu_dereference(sbi->s_group_info);
3465 	while (i-- > 0)
3466 		kfree(group_info[i]);
3467 	rcu_read_unlock();
3468 	iput(sbi->s_buddy_cache);
3469 err_freesgi:
3470 	rcu_read_lock();
3471 	kvfree(rcu_dereference(sbi->s_group_info));
3472 	rcu_read_unlock();
3473 	return -ENOMEM;
3474 }
3475 
ext4_groupinfo_destroy_slabs(void)3476 static void ext4_groupinfo_destroy_slabs(void)
3477 {
3478 	int i;
3479 
3480 	for (i = 0; i < NR_GRPINFO_CACHES; i++) {
3481 		kmem_cache_destroy(ext4_groupinfo_caches[i]);
3482 		ext4_groupinfo_caches[i] = NULL;
3483 	}
3484 }
3485 
ext4_groupinfo_create_slab(size_t size)3486 static int ext4_groupinfo_create_slab(size_t size)
3487 {
3488 	static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
3489 	int slab_size;
3490 	int blocksize_bits = order_base_2(size);
3491 	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
3492 	struct kmem_cache *cachep;
3493 
3494 	if (cache_index >= NR_GRPINFO_CACHES)
3495 		return -EINVAL;
3496 
3497 	if (unlikely(cache_index < 0))
3498 		cache_index = 0;
3499 
3500 	mutex_lock(&ext4_grpinfo_slab_create_mutex);
3501 	if (ext4_groupinfo_caches[cache_index]) {
3502 		mutex_unlock(&ext4_grpinfo_slab_create_mutex);
3503 		return 0;	/* Already created */
3504 	}
3505 
3506 	slab_size = offsetof(struct ext4_group_info,
3507 				bb_counters[blocksize_bits + 2]);
3508 
3509 	cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
3510 					slab_size, 0, SLAB_RECLAIM_ACCOUNT,
3511 					NULL);
3512 
3513 	ext4_groupinfo_caches[cache_index] = cachep;
3514 
3515 	mutex_unlock(&ext4_grpinfo_slab_create_mutex);
3516 	if (!cachep) {
3517 		printk(KERN_EMERG
3518 		       "EXT4-fs: no memory for groupinfo slab cache\n");
3519 		return -ENOMEM;
3520 	}
3521 
3522 	return 0;
3523 }
3524 
ext4_discard_work(struct work_struct * work)3525 static void ext4_discard_work(struct work_struct *work)
3526 {
3527 	struct ext4_sb_info *sbi = container_of(work,
3528 			struct ext4_sb_info, s_discard_work);
3529 	struct super_block *sb = sbi->s_sb;
3530 	struct ext4_free_data *fd, *nfd;
3531 	struct ext4_buddy e4b;
3532 	LIST_HEAD(discard_list);
3533 	ext4_group_t grp, load_grp;
3534 	int err = 0;
3535 
3536 	spin_lock(&sbi->s_md_lock);
3537 	list_splice_init(&sbi->s_discard_list, &discard_list);
3538 	spin_unlock(&sbi->s_md_lock);
3539 
3540 	load_grp = UINT_MAX;
3541 	list_for_each_entry_safe(fd, nfd, &discard_list, efd_list) {
3542 		/*
3543 		 * If filesystem is umounting or no memory or suffering
3544 		 * from no space, give up the discard
3545 		 */
3546 		if ((sb->s_flags & SB_ACTIVE) && !err &&
3547 		    !atomic_read(&sbi->s_retry_alloc_pending)) {
3548 			grp = fd->efd_group;
3549 			if (grp != load_grp) {
3550 				if (load_grp != UINT_MAX)
3551 					ext4_mb_unload_buddy(&e4b);
3552 
3553 				err = ext4_mb_load_buddy(sb, grp, &e4b);
3554 				if (err) {
3555 					kmem_cache_free(ext4_free_data_cachep, fd);
3556 					load_grp = UINT_MAX;
3557 					continue;
3558 				} else {
3559 					load_grp = grp;
3560 				}
3561 			}
3562 
3563 			ext4_lock_group(sb, grp);
3564 			ext4_try_to_trim_range(sb, &e4b, fd->efd_start_cluster,
3565 						fd->efd_start_cluster + fd->efd_count - 1, 1);
3566 			ext4_unlock_group(sb, grp);
3567 		}
3568 		kmem_cache_free(ext4_free_data_cachep, fd);
3569 	}
3570 
3571 	if (load_grp != UINT_MAX)
3572 		ext4_mb_unload_buddy(&e4b);
3573 }
3574 
ext4_mb_init(struct super_block * sb)3575 int ext4_mb_init(struct super_block *sb)
3576 {
3577 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3578 	unsigned i, j;
3579 	unsigned offset, offset_incr;
3580 	unsigned max;
3581 	int ret;
3582 
3583 	i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets);
3584 
3585 	sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
3586 	if (sbi->s_mb_offsets == NULL) {
3587 		ret = -ENOMEM;
3588 		goto out;
3589 	}
3590 
3591 	i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs);
3592 	sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
3593 	if (sbi->s_mb_maxs == NULL) {
3594 		ret = -ENOMEM;
3595 		goto out;
3596 	}
3597 
3598 	ret = ext4_groupinfo_create_slab(sb->s_blocksize);
3599 	if (ret < 0)
3600 		goto out;
3601 
3602 	/* order 0 is regular bitmap */
3603 	sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
3604 	sbi->s_mb_offsets[0] = 0;
3605 
3606 	i = 1;
3607 	offset = 0;
3608 	offset_incr = 1 << (sb->s_blocksize_bits - 1);
3609 	max = sb->s_blocksize << 2;
3610 	do {
3611 		sbi->s_mb_offsets[i] = offset;
3612 		sbi->s_mb_maxs[i] = max;
3613 		offset += offset_incr;
3614 		offset_incr = offset_incr >> 1;
3615 		max = max >> 1;
3616 		i++;
3617 	} while (i < MB_NUM_ORDERS(sb));
3618 
3619 	sbi->s_mb_avg_fragment_size =
3620 		kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head),
3621 			GFP_KERNEL);
3622 	if (!sbi->s_mb_avg_fragment_size) {
3623 		ret = -ENOMEM;
3624 		goto out;
3625 	}
3626 	sbi->s_mb_avg_fragment_size_locks =
3627 		kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t),
3628 			GFP_KERNEL);
3629 	if (!sbi->s_mb_avg_fragment_size_locks) {
3630 		ret = -ENOMEM;
3631 		goto out;
3632 	}
3633 	for (i = 0; i < MB_NUM_ORDERS(sb); i++) {
3634 		INIT_LIST_HEAD(&sbi->s_mb_avg_fragment_size[i]);
3635 		rwlock_init(&sbi->s_mb_avg_fragment_size_locks[i]);
3636 	}
3637 	sbi->s_mb_largest_free_orders =
3638 		kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head),
3639 			GFP_KERNEL);
3640 	if (!sbi->s_mb_largest_free_orders) {
3641 		ret = -ENOMEM;
3642 		goto out;
3643 	}
3644 	sbi->s_mb_largest_free_orders_locks =
3645 		kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t),
3646 			GFP_KERNEL);
3647 	if (!sbi->s_mb_largest_free_orders_locks) {
3648 		ret = -ENOMEM;
3649 		goto out;
3650 	}
3651 	for (i = 0; i < MB_NUM_ORDERS(sb); i++) {
3652 		INIT_LIST_HEAD(&sbi->s_mb_largest_free_orders[i]);
3653 		rwlock_init(&sbi->s_mb_largest_free_orders_locks[i]);
3654 	}
3655 
3656 	spin_lock_init(&sbi->s_md_lock);
3657 	sbi->s_mb_free_pending = 0;
3658 	INIT_LIST_HEAD(&sbi->s_freed_data_list);
3659 	INIT_LIST_HEAD(&sbi->s_discard_list);
3660 	INIT_WORK(&sbi->s_discard_work, ext4_discard_work);
3661 	atomic_set(&sbi->s_retry_alloc_pending, 0);
3662 
3663 	sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
3664 	sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
3665 	sbi->s_mb_stats = MB_DEFAULT_STATS;
3666 	sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
3667 	sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
3668 	sbi->s_mb_best_avail_max_trim_order = MB_DEFAULT_BEST_AVAIL_TRIM_ORDER;
3669 
3670 	/*
3671 	 * The default group preallocation is 512, which for 4k block
3672 	 * sizes translates to 2 megabytes.  However for bigalloc file
3673 	 * systems, this is probably too big (i.e, if the cluster size
3674 	 * is 1 megabyte, then group preallocation size becomes half a
3675 	 * gigabyte!).  As a default, we will keep a two megabyte
3676 	 * group pralloc size for cluster sizes up to 64k, and after
3677 	 * that, we will force a minimum group preallocation size of
3678 	 * 32 clusters.  This translates to 8 megs when the cluster
3679 	 * size is 256k, and 32 megs when the cluster size is 1 meg,
3680 	 * which seems reasonable as a default.
3681 	 */
3682 	sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
3683 				       sbi->s_cluster_bits, 32);
3684 	/*
3685 	 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
3686 	 * to the lowest multiple of s_stripe which is bigger than
3687 	 * the s_mb_group_prealloc as determined above. We want
3688 	 * the preallocation size to be an exact multiple of the
3689 	 * RAID stripe size so that preallocations don't fragment
3690 	 * the stripes.
3691 	 */
3692 	if (sbi->s_stripe > 1) {
3693 		sbi->s_mb_group_prealloc = roundup(
3694 			sbi->s_mb_group_prealloc, EXT4_B2C(sbi, sbi->s_stripe));
3695 	}
3696 
3697 	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
3698 	if (sbi->s_locality_groups == NULL) {
3699 		ret = -ENOMEM;
3700 		goto out;
3701 	}
3702 	for_each_possible_cpu(i) {
3703 		struct ext4_locality_group *lg;
3704 		lg = per_cpu_ptr(sbi->s_locality_groups, i);
3705 		mutex_init(&lg->lg_mutex);
3706 		for (j = 0; j < PREALLOC_TB_SIZE; j++)
3707 			INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
3708 		spin_lock_init(&lg->lg_prealloc_lock);
3709 	}
3710 
3711 	if (bdev_nonrot(sb->s_bdev))
3712 		sbi->s_mb_max_linear_groups = 0;
3713 	else
3714 		sbi->s_mb_max_linear_groups = MB_DEFAULT_LINEAR_LIMIT;
3715 	/* init file for buddy data */
3716 	ret = ext4_mb_init_backend(sb);
3717 	if (ret != 0)
3718 		goto out_free_locality_groups;
3719 
3720 	return 0;
3721 
3722 out_free_locality_groups:
3723 	free_percpu(sbi->s_locality_groups);
3724 	sbi->s_locality_groups = NULL;
3725 out:
3726 	kfree(sbi->s_mb_avg_fragment_size);
3727 	kfree(sbi->s_mb_avg_fragment_size_locks);
3728 	kfree(sbi->s_mb_largest_free_orders);
3729 	kfree(sbi->s_mb_largest_free_orders_locks);
3730 	kfree(sbi->s_mb_offsets);
3731 	sbi->s_mb_offsets = NULL;
3732 	kfree(sbi->s_mb_maxs);
3733 	sbi->s_mb_maxs = NULL;
3734 	return ret;
3735 }
3736 
3737 /* need to called with the ext4 group lock held */
ext4_mb_cleanup_pa(struct ext4_group_info * grp)3738 static int ext4_mb_cleanup_pa(struct ext4_group_info *grp)
3739 {
3740 	struct ext4_prealloc_space *pa;
3741 	struct list_head *cur, *tmp;
3742 	int count = 0;
3743 
3744 	list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
3745 		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
3746 		list_del(&pa->pa_group_list);
3747 		count++;
3748 		kmem_cache_free(ext4_pspace_cachep, pa);
3749 	}
3750 	return count;
3751 }
3752 
ext4_mb_release(struct super_block * sb)3753 int ext4_mb_release(struct super_block *sb)
3754 {
3755 	ext4_group_t ngroups = ext4_get_groups_count(sb);
3756 	ext4_group_t i;
3757 	int num_meta_group_infos;
3758 	struct ext4_group_info *grinfo, ***group_info;
3759 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3760 	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
3761 	int count;
3762 
3763 	if (test_opt(sb, DISCARD)) {
3764 		/*
3765 		 * wait the discard work to drain all of ext4_free_data
3766 		 */
3767 		flush_work(&sbi->s_discard_work);
3768 		WARN_ON_ONCE(!list_empty(&sbi->s_discard_list));
3769 	}
3770 
3771 	if (sbi->s_group_info) {
3772 		for (i = 0; i < ngroups; i++) {
3773 			cond_resched();
3774 			grinfo = ext4_get_group_info(sb, i);
3775 			if (!grinfo)
3776 				continue;
3777 			mb_group_bb_bitmap_free(grinfo);
3778 			ext4_lock_group(sb, i);
3779 			count = ext4_mb_cleanup_pa(grinfo);
3780 			if (count)
3781 				mb_debug(sb, "mballoc: %d PAs left\n",
3782 					 count);
3783 			ext4_unlock_group(sb, i);
3784 			kmem_cache_free(cachep, grinfo);
3785 		}
3786 		num_meta_group_infos = (ngroups +
3787 				EXT4_DESC_PER_BLOCK(sb) - 1) >>
3788 			EXT4_DESC_PER_BLOCK_BITS(sb);
3789 		rcu_read_lock();
3790 		group_info = rcu_dereference(sbi->s_group_info);
3791 		for (i = 0; i < num_meta_group_infos; i++)
3792 			kfree(group_info[i]);
3793 		kvfree(group_info);
3794 		rcu_read_unlock();
3795 	}
3796 	kfree(sbi->s_mb_avg_fragment_size);
3797 	kfree(sbi->s_mb_avg_fragment_size_locks);
3798 	kfree(sbi->s_mb_largest_free_orders);
3799 	kfree(sbi->s_mb_largest_free_orders_locks);
3800 	kfree(sbi->s_mb_offsets);
3801 	kfree(sbi->s_mb_maxs);
3802 	iput(sbi->s_buddy_cache);
3803 	if (sbi->s_mb_stats) {
3804 		ext4_msg(sb, KERN_INFO,
3805 		       "mballoc: %u blocks %u reqs (%u success)",
3806 				atomic_read(&sbi->s_bal_allocated),
3807 				atomic_read(&sbi->s_bal_reqs),
3808 				atomic_read(&sbi->s_bal_success));
3809 		ext4_msg(sb, KERN_INFO,
3810 		      "mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
3811 				"%u 2^N hits, %u breaks, %u lost",
3812 				atomic_read(&sbi->s_bal_ex_scanned),
3813 				atomic_read(&sbi->s_bal_groups_scanned),
3814 				atomic_read(&sbi->s_bal_goals),
3815 				atomic_read(&sbi->s_bal_2orders),
3816 				atomic_read(&sbi->s_bal_breaks),
3817 				atomic_read(&sbi->s_mb_lost_chunks));
3818 		ext4_msg(sb, KERN_INFO,
3819 		       "mballoc: %u generated and it took %llu",
3820 				atomic_read(&sbi->s_mb_buddies_generated),
3821 				atomic64_read(&sbi->s_mb_generation_time));
3822 		ext4_msg(sb, KERN_INFO,
3823 		       "mballoc: %u preallocated, %u discarded",
3824 				atomic_read(&sbi->s_mb_preallocated),
3825 				atomic_read(&sbi->s_mb_discarded));
3826 	}
3827 
3828 	free_percpu(sbi->s_locality_groups);
3829 
3830 	return 0;
3831 }
3832 
ext4_issue_discard(struct super_block * sb,ext4_group_t block_group,ext4_grpblk_t cluster,int count,struct bio ** biop)3833 static inline int ext4_issue_discard(struct super_block *sb,
3834 		ext4_group_t block_group, ext4_grpblk_t cluster, int count,
3835 		struct bio **biop)
3836 {
3837 	ext4_fsblk_t discard_block;
3838 
3839 	discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
3840 			 ext4_group_first_block_no(sb, block_group));
3841 	count = EXT4_C2B(EXT4_SB(sb), count);
3842 	trace_ext4_discard_blocks(sb,
3843 			(unsigned long long) discard_block, count);
3844 	if (biop) {
3845 		return __blkdev_issue_discard(sb->s_bdev,
3846 			(sector_t)discard_block << (sb->s_blocksize_bits - 9),
3847 			(sector_t)count << (sb->s_blocksize_bits - 9),
3848 			GFP_NOFS, biop);
3849 	} else
3850 		return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
3851 }
3852 
ext4_free_data_in_buddy(struct super_block * sb,struct ext4_free_data * entry)3853 static void ext4_free_data_in_buddy(struct super_block *sb,
3854 				    struct ext4_free_data *entry)
3855 {
3856 	struct ext4_buddy e4b;
3857 	struct ext4_group_info *db;
3858 	int err, count = 0;
3859 
3860 	mb_debug(sb, "gonna free %u blocks in group %u (0x%p):",
3861 		 entry->efd_count, entry->efd_group, entry);
3862 
3863 	err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
3864 	/* we expect to find existing buddy because it's pinned */
3865 	BUG_ON(err != 0);
3866 
3867 	spin_lock(&EXT4_SB(sb)->s_md_lock);
3868 	EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;
3869 	spin_unlock(&EXT4_SB(sb)->s_md_lock);
3870 
3871 	db = e4b.bd_info;
3872 	/* there are blocks to put in buddy to make them really free */
3873 	count += entry->efd_count;
3874 	ext4_lock_group(sb, entry->efd_group);
3875 	/* Take it out of per group rb tree */
3876 	rb_erase(&entry->efd_node, &(db->bb_free_root));
3877 	mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
3878 
3879 	/*
3880 	 * Clear the trimmed flag for the group so that the next
3881 	 * ext4_trim_fs can trim it.
3882 	 * If the volume is mounted with -o discard, online discard
3883 	 * is supported and the free blocks will be trimmed online.
3884 	 */
3885 	if (!test_opt(sb, DISCARD))
3886 		EXT4_MB_GRP_CLEAR_TRIMMED(db);
3887 
3888 	if (!db->bb_free_root.rb_node) {
3889 		/* No more items in the per group rb tree
3890 		 * balance refcounts from ext4_mb_free_metadata()
3891 		 */
3892 		put_page(e4b.bd_buddy_page);
3893 		put_page(e4b.bd_bitmap_page);
3894 	}
3895 	ext4_unlock_group(sb, entry->efd_group);
3896 	ext4_mb_unload_buddy(&e4b);
3897 
3898 	mb_debug(sb, "freed %d blocks in 1 structures\n", count);
3899 }
3900 
3901 /*
3902  * This function is called by the jbd2 layer once the commit has finished,
3903  * so we know we can free the blocks that were released with that commit.
3904  */
ext4_process_freed_data(struct super_block * sb,tid_t commit_tid)3905 void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid)
3906 {
3907 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3908 	struct ext4_free_data *entry, *tmp;
3909 	LIST_HEAD(freed_data_list);
3910 	struct list_head *cut_pos = NULL;
3911 	bool wake;
3912 
3913 	spin_lock(&sbi->s_md_lock);
3914 	list_for_each_entry(entry, &sbi->s_freed_data_list, efd_list) {
3915 		if (entry->efd_tid != commit_tid)
3916 			break;
3917 		cut_pos = &entry->efd_list;
3918 	}
3919 	if (cut_pos)
3920 		list_cut_position(&freed_data_list, &sbi->s_freed_data_list,
3921 				  cut_pos);
3922 	spin_unlock(&sbi->s_md_lock);
3923 
3924 	list_for_each_entry(entry, &freed_data_list, efd_list)
3925 		ext4_free_data_in_buddy(sb, entry);
3926 
3927 	if (test_opt(sb, DISCARD)) {
3928 		spin_lock(&sbi->s_md_lock);
3929 		wake = list_empty(&sbi->s_discard_list);
3930 		list_splice_tail(&freed_data_list, &sbi->s_discard_list);
3931 		spin_unlock(&sbi->s_md_lock);
3932 		if (wake)
3933 			queue_work(system_unbound_wq, &sbi->s_discard_work);
3934 	} else {
3935 		list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list)
3936 			kmem_cache_free(ext4_free_data_cachep, entry);
3937 	}
3938 }
3939 
ext4_init_mballoc(void)3940 int __init ext4_init_mballoc(void)
3941 {
3942 	ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
3943 					SLAB_RECLAIM_ACCOUNT);
3944 	if (ext4_pspace_cachep == NULL)
3945 		goto out;
3946 
3947 	ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
3948 				    SLAB_RECLAIM_ACCOUNT);
3949 	if (ext4_ac_cachep == NULL)
3950 		goto out_pa_free;
3951 
3952 	ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
3953 					   SLAB_RECLAIM_ACCOUNT);
3954 	if (ext4_free_data_cachep == NULL)
3955 		goto out_ac_free;
3956 
3957 	return 0;
3958 
3959 out_ac_free:
3960 	kmem_cache_destroy(ext4_ac_cachep);
3961 out_pa_free:
3962 	kmem_cache_destroy(ext4_pspace_cachep);
3963 out:
3964 	return -ENOMEM;
3965 }
3966 
ext4_exit_mballoc(void)3967 void ext4_exit_mballoc(void)
3968 {
3969 	/*
3970 	 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
3971 	 * before destroying the slab cache.
3972 	 */
3973 	rcu_barrier();
3974 	kmem_cache_destroy(ext4_pspace_cachep);
3975 	kmem_cache_destroy(ext4_ac_cachep);
3976 	kmem_cache_destroy(ext4_free_data_cachep);
3977 	ext4_groupinfo_destroy_slabs();
3978 }
3979 
3980 
3981 /*
3982  * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
3983  * Returns 0 if success or error code
3984  */
3985 static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context * ac,handle_t * handle,unsigned int reserv_clstrs)3986 ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
3987 				handle_t *handle, unsigned int reserv_clstrs)
3988 {
3989 	struct buffer_head *bitmap_bh = NULL;
3990 	struct ext4_group_desc *gdp;
3991 	struct buffer_head *gdp_bh;
3992 	struct ext4_sb_info *sbi;
3993 	struct super_block *sb;
3994 	ext4_fsblk_t block;
3995 	int err, len;
3996 
3997 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3998 	BUG_ON(ac->ac_b_ex.fe_len <= 0);
3999 
4000 	sb = ac->ac_sb;
4001 	sbi = EXT4_SB(sb);
4002 
4003 	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
4004 	if (IS_ERR(bitmap_bh)) {
4005 		return PTR_ERR(bitmap_bh);
4006 	}
4007 
4008 	BUFFER_TRACE(bitmap_bh, "getting write access");
4009 	err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
4010 					    EXT4_JTR_NONE);
4011 	if (err)
4012 		goto out_err;
4013 
4014 	err = -EIO;
4015 	gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
4016 	if (!gdp)
4017 		goto out_err;
4018 
4019 	ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
4020 			ext4_free_group_clusters(sb, gdp));
4021 
4022 	BUFFER_TRACE(gdp_bh, "get_write_access");
4023 	err = ext4_journal_get_write_access(handle, sb, gdp_bh, EXT4_JTR_NONE);
4024 	if (err)
4025 		goto out_err;
4026 
4027 	block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
4028 
4029 	len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4030 	if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
4031 		ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
4032 			   "fs metadata", block, block+len);
4033 		/* File system mounted not to panic on error
4034 		 * Fix the bitmap and return EFSCORRUPTED
4035 		 * We leak some of the blocks here.
4036 		 */
4037 		ext4_lock_group(sb, ac->ac_b_ex.fe_group);
4038 		mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
4039 			      ac->ac_b_ex.fe_len);
4040 		ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
4041 		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4042 		if (!err)
4043 			err = -EFSCORRUPTED;
4044 		goto out_err;
4045 	}
4046 
4047 	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
4048 #ifdef AGGRESSIVE_CHECK
4049 	{
4050 		int i;
4051 		for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
4052 			BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
4053 						bitmap_bh->b_data));
4054 		}
4055 	}
4056 #endif
4057 	mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
4058 		      ac->ac_b_ex.fe_len);
4059 	if (ext4_has_group_desc_csum(sb) &&
4060 	    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
4061 		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
4062 		ext4_free_group_clusters_set(sb, gdp,
4063 					     ext4_free_clusters_after_init(sb,
4064 						ac->ac_b_ex.fe_group, gdp));
4065 	}
4066 	len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
4067 	ext4_free_group_clusters_set(sb, gdp, len);
4068 	ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
4069 	ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
4070 
4071 	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
4072 	percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
4073 	/*
4074 	 * Now reduce the dirty block count also. Should not go negative
4075 	 */
4076 	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
4077 		/* release all the reserved blocks if non delalloc */
4078 		percpu_counter_sub(&sbi->s_dirtyclusters_counter,
4079 				   reserv_clstrs);
4080 
4081 	if (sbi->s_log_groups_per_flex) {
4082 		ext4_group_t flex_group = ext4_flex_group(sbi,
4083 							  ac->ac_b_ex.fe_group);
4084 		atomic64_sub(ac->ac_b_ex.fe_len,
4085 			     &sbi_array_rcu_deref(sbi, s_flex_groups,
4086 						  flex_group)->free_clusters);
4087 	}
4088 
4089 	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4090 	if (err)
4091 		goto out_err;
4092 	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
4093 
4094 out_err:
4095 	brelse(bitmap_bh);
4096 	return err;
4097 }
4098 
4099 /*
4100  * Idempotent helper for Ext4 fast commit replay path to set the state of
4101  * blocks in bitmaps and update counters.
4102  */
ext4_mb_mark_bb(struct super_block * sb,ext4_fsblk_t block,int len,int state)4103 void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
4104 			int len, int state)
4105 {
4106 	struct buffer_head *bitmap_bh = NULL;
4107 	struct ext4_group_desc *gdp;
4108 	struct buffer_head *gdp_bh;
4109 	struct ext4_sb_info *sbi = EXT4_SB(sb);
4110 	ext4_group_t group;
4111 	ext4_grpblk_t blkoff;
4112 	int i, err = 0;
4113 	int already;
4114 	unsigned int clen, clen_changed, thisgrp_len;
4115 
4116 	while (len > 0) {
4117 		ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
4118 
4119 		/*
4120 		 * Check to see if we are freeing blocks across a group
4121 		 * boundary.
4122 		 * In case of flex_bg, this can happen that (block, len) may
4123 		 * span across more than one group. In that case we need to
4124 		 * get the corresponding group metadata to work with.
4125 		 * For this we have goto again loop.
4126 		 */
4127 		thisgrp_len = min_t(unsigned int, (unsigned int)len,
4128 			EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
4129 		clen = EXT4_NUM_B2C(sbi, thisgrp_len);
4130 
4131 		if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) {
4132 			ext4_error(sb, "Marking blocks in system zone - "
4133 				   "Block = %llu, len = %u",
4134 				   block, thisgrp_len);
4135 			bitmap_bh = NULL;
4136 			break;
4137 		}
4138 
4139 		bitmap_bh = ext4_read_block_bitmap(sb, group);
4140 		if (IS_ERR(bitmap_bh)) {
4141 			err = PTR_ERR(bitmap_bh);
4142 			bitmap_bh = NULL;
4143 			break;
4144 		}
4145 
4146 		err = -EIO;
4147 		gdp = ext4_get_group_desc(sb, group, &gdp_bh);
4148 		if (!gdp)
4149 			break;
4150 
4151 		ext4_lock_group(sb, group);
4152 		already = 0;
4153 		for (i = 0; i < clen; i++)
4154 			if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
4155 					 !state)
4156 				already++;
4157 
4158 		clen_changed = clen - already;
4159 		if (state)
4160 			mb_set_bits(bitmap_bh->b_data, blkoff, clen);
4161 		else
4162 			mb_clear_bits(bitmap_bh->b_data, blkoff, clen);
4163 		if (ext4_has_group_desc_csum(sb) &&
4164 		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
4165 			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
4166 			ext4_free_group_clusters_set(sb, gdp,
4167 			     ext4_free_clusters_after_init(sb, group, gdp));
4168 		}
4169 		if (state)
4170 			clen = ext4_free_group_clusters(sb, gdp) - clen_changed;
4171 		else
4172 			clen = ext4_free_group_clusters(sb, gdp) + clen_changed;
4173 
4174 		ext4_free_group_clusters_set(sb, gdp, clen);
4175 		ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
4176 		ext4_group_desc_csum_set(sb, group, gdp);
4177 
4178 		ext4_unlock_group(sb, group);
4179 
4180 		if (sbi->s_log_groups_per_flex) {
4181 			ext4_group_t flex_group = ext4_flex_group(sbi, group);
4182 			struct flex_groups *fg = sbi_array_rcu_deref(sbi,
4183 						   s_flex_groups, flex_group);
4184 
4185 			if (state)
4186 				atomic64_sub(clen_changed, &fg->free_clusters);
4187 			else
4188 				atomic64_add(clen_changed, &fg->free_clusters);
4189 
4190 		}
4191 
4192 		err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
4193 		if (err)
4194 			break;
4195 		sync_dirty_buffer(bitmap_bh);
4196 		err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
4197 		sync_dirty_buffer(gdp_bh);
4198 		if (err)
4199 			break;
4200 
4201 		block += thisgrp_len;
4202 		len -= thisgrp_len;
4203 		brelse(bitmap_bh);
4204 		BUG_ON(len < 0);
4205 	}
4206 
4207 	if (err)
4208 		brelse(bitmap_bh);
4209 }
4210 
4211 /*
4212  * here we normalize request for locality group
4213  * Group request are normalized to s_mb_group_prealloc, which goes to
4214  * s_strip if we set the same via mount option.
4215  * s_mb_group_prealloc can be configured via
4216  * /sys/fs/ext4/<partition>/mb_group_prealloc
4217  *
4218  * XXX: should we try to preallocate more than the group has now?
4219  */
ext4_mb_normalize_group_request(struct ext4_allocation_context * ac)4220 static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
4221 {
4222 	struct super_block *sb = ac->ac_sb;
4223 	struct ext4_locality_group *lg = ac->ac_lg;
4224 
4225 	BUG_ON(lg == NULL);
4226 	ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
4227 	mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len);
4228 }
4229 
4230 /*
4231  * This function returns the next element to look at during inode
4232  * PA rbtree walk. We assume that we have held the inode PA rbtree lock
4233  * (ei->i_prealloc_lock)
4234  *
4235  * new_start	The start of the range we want to compare
4236  * cur_start	The existing start that we are comparing against
4237  * node	The node of the rb_tree
4238  */
4239 static inline struct rb_node*
ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start,ext4_lblk_t cur_start,struct rb_node * node)4240 ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start, ext4_lblk_t cur_start, struct rb_node *node)
4241 {
4242 	if (new_start < cur_start)
4243 		return node->rb_left;
4244 	else
4245 		return node->rb_right;
4246 }
4247 
4248 static inline void
ext4_mb_pa_assert_overlap(struct ext4_allocation_context * ac,ext4_lblk_t start,loff_t end)4249 ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac,
4250 			  ext4_lblk_t start, loff_t end)
4251 {
4252 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4253 	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
4254 	struct ext4_prealloc_space *tmp_pa;
4255 	ext4_lblk_t tmp_pa_start;
4256 	loff_t tmp_pa_end;
4257 	struct rb_node *iter;
4258 
4259 	read_lock(&ei->i_prealloc_lock);
4260 	for (iter = ei->i_prealloc_node.rb_node; iter;
4261 	     iter = ext4_mb_pa_rb_next_iter(start, tmp_pa_start, iter)) {
4262 		tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
4263 				  pa_node.inode_node);
4264 		tmp_pa_start = tmp_pa->pa_lstart;
4265 		tmp_pa_end = pa_logical_end(sbi, tmp_pa);
4266 
4267 		spin_lock(&tmp_pa->pa_lock);
4268 		if (tmp_pa->pa_deleted == 0)
4269 			BUG_ON(!(start >= tmp_pa_end || end <= tmp_pa_start));
4270 		spin_unlock(&tmp_pa->pa_lock);
4271 	}
4272 	read_unlock(&ei->i_prealloc_lock);
4273 }
4274 
4275 /*
4276  * Given an allocation context "ac" and a range "start", "end", check
4277  * and adjust boundaries if the range overlaps with any of the existing
4278  * preallocatoins stored in the corresponding inode of the allocation context.
4279  *
4280  * Parameters:
4281  *	ac			allocation context
4282  *	start			start of the new range
4283  *	end			end of the new range
4284  */
4285 static inline void
ext4_mb_pa_adjust_overlap(struct ext4_allocation_context * ac,ext4_lblk_t * start,loff_t * end)4286 ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac,
4287 			  ext4_lblk_t *start, loff_t *end)
4288 {
4289 	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
4290 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4291 	struct ext4_prealloc_space *tmp_pa = NULL, *left_pa = NULL, *right_pa = NULL;
4292 	struct rb_node *iter;
4293 	ext4_lblk_t new_start, tmp_pa_start, right_pa_start = -1;
4294 	loff_t new_end, tmp_pa_end, left_pa_end = -1;
4295 
4296 	new_start = *start;
4297 	new_end = *end;
4298 
4299 	/*
4300 	 * Adjust the normalized range so that it doesn't overlap with any
4301 	 * existing preallocated blocks(PAs). Make sure to hold the rbtree lock
4302 	 * so it doesn't change underneath us.
4303 	 */
4304 	read_lock(&ei->i_prealloc_lock);
4305 
4306 	/* Step 1: find any one immediate neighboring PA of the normalized range */
4307 	for (iter = ei->i_prealloc_node.rb_node; iter;
4308 	     iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical,
4309 					    tmp_pa_start, iter)) {
4310 		tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
4311 				  pa_node.inode_node);
4312 		tmp_pa_start = tmp_pa->pa_lstart;
4313 		tmp_pa_end = pa_logical_end(sbi, tmp_pa);
4314 
4315 		/* PA must not overlap original request */
4316 		spin_lock(&tmp_pa->pa_lock);
4317 		if (tmp_pa->pa_deleted == 0)
4318 			BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end ||
4319 				 ac->ac_o_ex.fe_logical < tmp_pa_start));
4320 		spin_unlock(&tmp_pa->pa_lock);
4321 	}
4322 
4323 	/*
4324 	 * Step 2: check if the found PA is left or right neighbor and
4325 	 * get the other neighbor
4326 	 */
4327 	if (tmp_pa) {
4328 		if (tmp_pa->pa_lstart < ac->ac_o_ex.fe_logical) {
4329 			struct rb_node *tmp;
4330 
4331 			left_pa = tmp_pa;
4332 			tmp = rb_next(&left_pa->pa_node.inode_node);
4333 			if (tmp) {
4334 				right_pa = rb_entry(tmp,
4335 						    struct ext4_prealloc_space,
4336 						    pa_node.inode_node);
4337 			}
4338 		} else {
4339 			struct rb_node *tmp;
4340 
4341 			right_pa = tmp_pa;
4342 			tmp = rb_prev(&right_pa->pa_node.inode_node);
4343 			if (tmp) {
4344 				left_pa = rb_entry(tmp,
4345 						   struct ext4_prealloc_space,
4346 						   pa_node.inode_node);
4347 			}
4348 		}
4349 	}
4350 
4351 	/* Step 3: get the non deleted neighbors */
4352 	if (left_pa) {
4353 		for (iter = &left_pa->pa_node.inode_node;;
4354 		     iter = rb_prev(iter)) {
4355 			if (!iter) {
4356 				left_pa = NULL;
4357 				break;
4358 			}
4359 
4360 			tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
4361 					  pa_node.inode_node);
4362 			left_pa = tmp_pa;
4363 			spin_lock(&tmp_pa->pa_lock);
4364 			if (tmp_pa->pa_deleted == 0) {
4365 				spin_unlock(&tmp_pa->pa_lock);
4366 				break;
4367 			}
4368 			spin_unlock(&tmp_pa->pa_lock);
4369 		}
4370 	}
4371 
4372 	if (right_pa) {
4373 		for (iter = &right_pa->pa_node.inode_node;;
4374 		     iter = rb_next(iter)) {
4375 			if (!iter) {
4376 				right_pa = NULL;
4377 				break;
4378 			}
4379 
4380 			tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
4381 					  pa_node.inode_node);
4382 			right_pa = tmp_pa;
4383 			spin_lock(&tmp_pa->pa_lock);
4384 			if (tmp_pa->pa_deleted == 0) {
4385 				spin_unlock(&tmp_pa->pa_lock);
4386 				break;
4387 			}
4388 			spin_unlock(&tmp_pa->pa_lock);
4389 		}
4390 	}
4391 
4392 	if (left_pa) {
4393 		left_pa_end = pa_logical_end(sbi, left_pa);
4394 		BUG_ON(left_pa_end > ac->ac_o_ex.fe_logical);
4395 	}
4396 
4397 	if (right_pa) {
4398 		right_pa_start = right_pa->pa_lstart;
4399 		BUG_ON(right_pa_start <= ac->ac_o_ex.fe_logical);
4400 	}
4401 
4402 	/* Step 4: trim our normalized range to not overlap with the neighbors */
4403 	if (left_pa) {
4404 		if (left_pa_end > new_start)
4405 			new_start = left_pa_end;
4406 	}
4407 
4408 	if (right_pa) {
4409 		if (right_pa_start < new_end)
4410 			new_end = right_pa_start;
4411 	}
4412 	read_unlock(&ei->i_prealloc_lock);
4413 
4414 	/* XXX: extra loop to check we really don't overlap preallocations */
4415 	ext4_mb_pa_assert_overlap(ac, new_start, new_end);
4416 
4417 	*start = new_start;
4418 	*end = new_end;
4419 }
4420 
4421 /*
4422  * Normalization means making request better in terms of
4423  * size and alignment
4424  */
4425 static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context * ac,struct ext4_allocation_request * ar)4426 ext4_mb_normalize_request(struct ext4_allocation_context *ac,
4427 				struct ext4_allocation_request *ar)
4428 {
4429 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4430 	struct ext4_super_block *es = sbi->s_es;
4431 	int bsbits, max;
4432 	loff_t size, start_off, end;
4433 	loff_t orig_size __maybe_unused;
4434 	ext4_lblk_t start;
4435 
4436 	/* do normalize only data requests, metadata requests
4437 	   do not need preallocation */
4438 	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
4439 		return;
4440 
4441 	/* sometime caller may want exact blocks */
4442 	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
4443 		return;
4444 
4445 	/* caller may indicate that preallocation isn't
4446 	 * required (it's a tail, for example) */
4447 	if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
4448 		return;
4449 
4450 	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
4451 		ext4_mb_normalize_group_request(ac);
4452 		return ;
4453 	}
4454 
4455 	bsbits = ac->ac_sb->s_blocksize_bits;
4456 
4457 	/* first, let's learn actual file size
4458 	 * given current request is allocated */
4459 	size = extent_logical_end(sbi, &ac->ac_o_ex);
4460 	size = size << bsbits;
4461 	if (size < i_size_read(ac->ac_inode))
4462 		size = i_size_read(ac->ac_inode);
4463 	orig_size = size;
4464 
4465 	/* max size of free chunks */
4466 	max = 2 << bsbits;
4467 
4468 #define NRL_CHECK_SIZE(req, size, max, chunk_size)	\
4469 		(req <= (size) || max <= (chunk_size))
4470 
4471 	/* first, try to predict filesize */
4472 	/* XXX: should this table be tunable? */
4473 	start_off = 0;
4474 	if (size <= 16 * 1024) {
4475 		size = 16 * 1024;
4476 	} else if (size <= 32 * 1024) {
4477 		size = 32 * 1024;
4478 	} else if (size <= 64 * 1024) {
4479 		size = 64 * 1024;
4480 	} else if (size <= 128 * 1024) {
4481 		size = 128 * 1024;
4482 	} else if (size <= 256 * 1024) {
4483 		size = 256 * 1024;
4484 	} else if (size <= 512 * 1024) {
4485 		size = 512 * 1024;
4486 	} else if (size <= 1024 * 1024) {
4487 		size = 1024 * 1024;
4488 	} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
4489 		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
4490 						(21 - bsbits)) << 21;
4491 		size = 2 * 1024 * 1024;
4492 	} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
4493 		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
4494 							(22 - bsbits)) << 22;
4495 		size = 4 * 1024 * 1024;
4496 	} else if (NRL_CHECK_SIZE(EXT4_C2B(sbi, ac->ac_o_ex.fe_len),
4497 					(8<<20)>>bsbits, max, 8 * 1024)) {
4498 		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
4499 							(23 - bsbits)) << 23;
4500 		size = 8 * 1024 * 1024;
4501 	} else {
4502 		start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
4503 		size	  = (loff_t) EXT4_C2B(sbi,
4504 					      ac->ac_o_ex.fe_len) << bsbits;
4505 	}
4506 	size = size >> bsbits;
4507 	start = start_off >> bsbits;
4508 
4509 	/*
4510 	 * For tiny groups (smaller than 8MB) the chosen allocation
4511 	 * alignment may be larger than group size. Make sure the
4512 	 * alignment does not move allocation to a different group which
4513 	 * makes mballoc fail assertions later.
4514 	 */
4515 	start = max(start, rounddown(ac->ac_o_ex.fe_logical,
4516 			(ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
4517 
4518 	/* avoid unnecessary preallocation that may trigger assertions */
4519 	if (start + size > EXT_MAX_BLOCKS)
4520 		size = EXT_MAX_BLOCKS - start;
4521 
4522 	/* don't cover already allocated blocks in selected range */
4523 	if (ar->pleft && start <= ar->lleft) {
4524 		size -= ar->lleft + 1 - start;
4525 		start = ar->lleft + 1;
4526 	}
4527 	if (ar->pright && start + size - 1 >= ar->lright)
4528 		size -= start + size - ar->lright;
4529 
4530 	/*
4531 	 * Trim allocation request for filesystems with artificially small
4532 	 * groups.
4533 	 */
4534 	if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
4535 		size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
4536 
4537 	end = start + size;
4538 
4539 	ext4_mb_pa_adjust_overlap(ac, &start, &end);
4540 
4541 	size = end - start;
4542 
4543 	/*
4544 	 * In this function "start" and "size" are normalized for better
4545 	 * alignment and length such that we could preallocate more blocks.
4546 	 * This normalization is done such that original request of
4547 	 * ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and
4548 	 * "size" boundaries.
4549 	 * (Note fe_len can be relaxed since FS block allocation API does not
4550 	 * provide gurantee on number of contiguous blocks allocation since that
4551 	 * depends upon free space left, etc).
4552 	 * In case of inode pa, later we use the allocated blocks
4553 	 * [pa_pstart + fe_logical - pa_lstart, fe_len/size] from the preallocated
4554 	 * range of goal/best blocks [start, size] to put it at the
4555 	 * ac_o_ex.fe_logical extent of this inode.
4556 	 * (See ext4_mb_use_inode_pa() for more details)
4557 	 */
4558 	if (start + size <= ac->ac_o_ex.fe_logical ||
4559 			start > ac->ac_o_ex.fe_logical) {
4560 		ext4_msg(ac->ac_sb, KERN_ERR,
4561 			 "start %lu, size %lu, fe_logical %lu",
4562 			 (unsigned long) start, (unsigned long) size,
4563 			 (unsigned long) ac->ac_o_ex.fe_logical);
4564 		BUG();
4565 	}
4566 	BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
4567 
4568 	/* now prepare goal request */
4569 
4570 	/* XXX: is it better to align blocks WRT to logical
4571 	 * placement or satisfy big request as is */
4572 	ac->ac_g_ex.fe_logical = start;
4573 	ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
4574 	ac->ac_orig_goal_len = ac->ac_g_ex.fe_len;
4575 
4576 	/* define goal start in order to merge */
4577 	if (ar->pright && (ar->lright == (start + size)) &&
4578 	    ar->pright >= size &&
4579 	    ar->pright - size >= le32_to_cpu(es->s_first_data_block)) {
4580 		/* merge to the right */
4581 		ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
4582 						&ac->ac_g_ex.fe_group,
4583 						&ac->ac_g_ex.fe_start);
4584 		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
4585 	}
4586 	if (ar->pleft && (ar->lleft + 1 == start) &&
4587 	    ar->pleft + 1 < ext4_blocks_count(es)) {
4588 		/* merge to the left */
4589 		ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
4590 						&ac->ac_g_ex.fe_group,
4591 						&ac->ac_g_ex.fe_start);
4592 		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
4593 	}
4594 
4595 	mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size,
4596 		 orig_size, start);
4597 }
4598 
ext4_mb_collect_stats(struct ext4_allocation_context * ac)4599 static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
4600 {
4601 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4602 
4603 	if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
4604 		atomic_inc(&sbi->s_bal_reqs);
4605 		atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
4606 		if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
4607 			atomic_inc(&sbi->s_bal_success);
4608 
4609 		atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
4610 		for (int i=0; i<EXT4_MB_NUM_CRS; i++) {
4611 			atomic_add(ac->ac_cX_found[i], &sbi->s_bal_cX_ex_scanned[i]);
4612 		}
4613 
4614 		atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
4615 		if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
4616 				ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
4617 			atomic_inc(&sbi->s_bal_goals);
4618 		/* did we allocate as much as normalizer originally wanted? */
4619 		if (ac->ac_f_ex.fe_len == ac->ac_orig_goal_len)
4620 			atomic_inc(&sbi->s_bal_len_goals);
4621 
4622 		if (ac->ac_found > sbi->s_mb_max_to_scan)
4623 			atomic_inc(&sbi->s_bal_breaks);
4624 	}
4625 
4626 	if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
4627 		trace_ext4_mballoc_alloc(ac);
4628 	else
4629 		trace_ext4_mballoc_prealloc(ac);
4630 }
4631 
4632 /*
4633  * Called on failure; free up any blocks from the inode PA for this
4634  * context.  We don't need this for MB_GROUP_PA because we only change
4635  * pa_free in ext4_mb_release_context(), but on failure, we've already
4636  * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
4637  */
ext4_discard_allocated_blocks(struct ext4_allocation_context * ac)4638 static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
4639 {
4640 	struct ext4_prealloc_space *pa = ac->ac_pa;
4641 	struct ext4_buddy e4b;
4642 	int err;
4643 
4644 	if (pa == NULL) {
4645 		if (ac->ac_f_ex.fe_len == 0)
4646 			return;
4647 		err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
4648 		if (WARN_RATELIMIT(err,
4649 				   "ext4: mb_load_buddy failed (%d)", err))
4650 			/*
4651 			 * This should never happen since we pin the
4652 			 * pages in the ext4_allocation_context so
4653 			 * ext4_mb_load_buddy() should never fail.
4654 			 */
4655 			return;
4656 		ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
4657 		mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
4658 			       ac->ac_f_ex.fe_len);
4659 		ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
4660 		ext4_mb_unload_buddy(&e4b);
4661 		return;
4662 	}
4663 	if (pa->pa_type == MB_INODE_PA) {
4664 		spin_lock(&pa->pa_lock);
4665 		pa->pa_free += ac->ac_b_ex.fe_len;
4666 		spin_unlock(&pa->pa_lock);
4667 	}
4668 }
4669 
4670 /*
4671  * use blocks preallocated to inode
4672  */
ext4_mb_use_inode_pa(struct ext4_allocation_context * ac,struct ext4_prealloc_space * pa)4673 static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
4674 				struct ext4_prealloc_space *pa)
4675 {
4676 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4677 	ext4_fsblk_t start;
4678 	ext4_fsblk_t end;
4679 	int len;
4680 
4681 	/* found preallocated blocks, use them */
4682 	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
4683 	end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
4684 		  start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
4685 	len = EXT4_NUM_B2C(sbi, end - start);
4686 	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
4687 					&ac->ac_b_ex.fe_start);
4688 	ac->ac_b_ex.fe_len = len;
4689 	ac->ac_status = AC_STATUS_FOUND;
4690 	ac->ac_pa = pa;
4691 
4692 	BUG_ON(start < pa->pa_pstart);
4693 	BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
4694 	BUG_ON(pa->pa_free < len);
4695 	BUG_ON(ac->ac_b_ex.fe_len <= 0);
4696 	pa->pa_free -= len;
4697 
4698 	mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa);
4699 }
4700 
4701 /*
4702  * use blocks preallocated to locality group
4703  */
ext4_mb_use_group_pa(struct ext4_allocation_context * ac,struct ext4_prealloc_space * pa)4704 static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
4705 				struct ext4_prealloc_space *pa)
4706 {
4707 	unsigned int len = ac->ac_o_ex.fe_len;
4708 
4709 	ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
4710 					&ac->ac_b_ex.fe_group,
4711 					&ac->ac_b_ex.fe_start);
4712 	ac->ac_b_ex.fe_len = len;
4713 	ac->ac_status = AC_STATUS_FOUND;
4714 	ac->ac_pa = pa;
4715 
4716 	/* we don't correct pa_pstart or pa_len here to avoid
4717 	 * possible race when the group is being loaded concurrently
4718 	 * instead we correct pa later, after blocks are marked
4719 	 * in on-disk bitmap -- see ext4_mb_release_context()
4720 	 * Other CPUs are prevented from allocating from this pa by lg_mutex
4721 	 */
4722 	mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n",
4723 		 pa->pa_lstart, len, pa);
4724 }
4725 
4726 /*
4727  * Return the prealloc space that have minimal distance
4728  * from the goal block. @cpa is the prealloc
4729  * space that is having currently known minimal distance
4730  * from the goal block.
4731  */
4732 static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,struct ext4_prealloc_space * pa,struct ext4_prealloc_space * cpa)4733 ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
4734 			struct ext4_prealloc_space *pa,
4735 			struct ext4_prealloc_space *cpa)
4736 {
4737 	ext4_fsblk_t cur_distance, new_distance;
4738 
4739 	if (cpa == NULL) {
4740 		atomic_inc(&pa->pa_count);
4741 		return pa;
4742 	}
4743 	cur_distance = abs(goal_block - cpa->pa_pstart);
4744 	new_distance = abs(goal_block - pa->pa_pstart);
4745 
4746 	if (cur_distance <= new_distance)
4747 		return cpa;
4748 
4749 	/* drop the previous reference */
4750 	atomic_dec(&cpa->pa_count);
4751 	atomic_inc(&pa->pa_count);
4752 	return pa;
4753 }
4754 
4755 /*
4756  * check if found pa meets EXT4_MB_HINT_GOAL_ONLY
4757  */
4758 static bool
ext4_mb_pa_goal_check(struct ext4_allocation_context * ac,struct ext4_prealloc_space * pa)4759 ext4_mb_pa_goal_check(struct ext4_allocation_context *ac,
4760 		      struct ext4_prealloc_space *pa)
4761 {
4762 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4763 	ext4_fsblk_t start;
4764 
4765 	if (likely(!(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)))
4766 		return true;
4767 
4768 	/*
4769 	 * If EXT4_MB_HINT_GOAL_ONLY is set, ac_g_ex will not be adjusted
4770 	 * in ext4_mb_normalize_request and will keep same with ac_o_ex
4771 	 * from ext4_mb_initialize_context. Choose ac_g_ex here to keep
4772 	 * consistent with ext4_mb_find_by_goal.
4773 	 */
4774 	start = pa->pa_pstart +
4775 		(ac->ac_g_ex.fe_logical - pa->pa_lstart);
4776 	if (ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex) != start)
4777 		return false;
4778 
4779 	if (ac->ac_g_ex.fe_len > pa->pa_len -
4780 	    EXT4_B2C(sbi, ac->ac_g_ex.fe_logical - pa->pa_lstart))
4781 		return false;
4782 
4783 	return true;
4784 }
4785 
4786 /*
4787  * search goal blocks in preallocated space
4788  */
4789 static noinline_for_stack bool
ext4_mb_use_preallocated(struct ext4_allocation_context * ac)4790 ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
4791 {
4792 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4793 	int order, i;
4794 	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
4795 	struct ext4_locality_group *lg;
4796 	struct ext4_prealloc_space *tmp_pa = NULL, *cpa = NULL;
4797 	struct rb_node *iter;
4798 	ext4_fsblk_t goal_block;
4799 
4800 	/* only data can be preallocated */
4801 	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
4802 		return false;
4803 
4804 	/*
4805 	 * first, try per-file preallocation by searching the inode pa rbtree.
4806 	 *
4807 	 * Here, we can't do a direct traversal of the tree because
4808 	 * ext4_mb_discard_group_preallocation() can paralelly mark the pa
4809 	 * deleted and that can cause direct traversal to skip some entries.
4810 	 */
4811 	read_lock(&ei->i_prealloc_lock);
4812 
4813 	if (RB_EMPTY_ROOT(&ei->i_prealloc_node)) {
4814 		goto try_group_pa;
4815 	}
4816 
4817 	/*
4818 	 * Step 1: Find a pa with logical start immediately adjacent to the
4819 	 * original logical start. This could be on the left or right.
4820 	 *
4821 	 * (tmp_pa->pa_lstart never changes so we can skip locking for it).
4822 	 */
4823 	for (iter = ei->i_prealloc_node.rb_node; iter;
4824 	     iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical,
4825 					    tmp_pa->pa_lstart, iter)) {
4826 		tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
4827 				  pa_node.inode_node);
4828 	}
4829 
4830 	/*
4831 	 * Step 2: The adjacent pa might be to the right of logical start, find
4832 	 * the left adjacent pa. After this step we'd have a valid tmp_pa whose
4833 	 * logical start is towards the left of original request's logical start
4834 	 */
4835 	if (tmp_pa->pa_lstart > ac->ac_o_ex.fe_logical) {
4836 		struct rb_node *tmp;
4837 		tmp = rb_prev(&tmp_pa->pa_node.inode_node);
4838 
4839 		if (tmp) {
4840 			tmp_pa = rb_entry(tmp, struct ext4_prealloc_space,
4841 					    pa_node.inode_node);
4842 		} else {
4843 			/*
4844 			 * If there is no adjacent pa to the left then finding
4845 			 * an overlapping pa is not possible hence stop searching
4846 			 * inode pa tree
4847 			 */
4848 			goto try_group_pa;
4849 		}
4850 	}
4851 
4852 	BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical));
4853 
4854 	/*
4855 	 * Step 3: If the left adjacent pa is deleted, keep moving left to find
4856 	 * the first non deleted adjacent pa. After this step we should have a
4857 	 * valid tmp_pa which is guaranteed to be non deleted.
4858 	 */
4859 	for (iter = &tmp_pa->pa_node.inode_node;; iter = rb_prev(iter)) {
4860 		if (!iter) {
4861 			/*
4862 			 * no non deleted left adjacent pa, so stop searching
4863 			 * inode pa tree
4864 			 */
4865 			goto try_group_pa;
4866 		}
4867 		tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
4868 				  pa_node.inode_node);
4869 		spin_lock(&tmp_pa->pa_lock);
4870 		if (tmp_pa->pa_deleted == 0) {
4871 			/*
4872 			 * We will keep holding the pa_lock from
4873 			 * this point on because we don't want group discard
4874 			 * to delete this pa underneath us. Since group
4875 			 * discard is anyways an ENOSPC operation it
4876 			 * should be okay for it to wait a few more cycles.
4877 			 */
4878 			break;
4879 		} else {
4880 			spin_unlock(&tmp_pa->pa_lock);
4881 		}
4882 	}
4883 
4884 	BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical));
4885 	BUG_ON(tmp_pa->pa_deleted == 1);
4886 
4887 	/*
4888 	 * Step 4: We now have the non deleted left adjacent pa. Only this
4889 	 * pa can possibly satisfy the request hence check if it overlaps
4890 	 * original logical start and stop searching if it doesn't.
4891 	 */
4892 	if (ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, tmp_pa)) {
4893 		spin_unlock(&tmp_pa->pa_lock);
4894 		goto try_group_pa;
4895 	}
4896 
4897 	/* non-extent files can't have physical blocks past 2^32 */
4898 	if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
4899 	    (tmp_pa->pa_pstart + EXT4_C2B(sbi, tmp_pa->pa_len) >
4900 	     EXT4_MAX_BLOCK_FILE_PHYS)) {
4901 		/*
4902 		 * Since PAs don't overlap, we won't find any other PA to
4903 		 * satisfy this.
4904 		 */
4905 		spin_unlock(&tmp_pa->pa_lock);
4906 		goto try_group_pa;
4907 	}
4908 
4909 	if (tmp_pa->pa_free && likely(ext4_mb_pa_goal_check(ac, tmp_pa))) {
4910 		atomic_inc(&tmp_pa->pa_count);
4911 		ext4_mb_use_inode_pa(ac, tmp_pa);
4912 		spin_unlock(&tmp_pa->pa_lock);
4913 		read_unlock(&ei->i_prealloc_lock);
4914 		return true;
4915 	} else {
4916 		/*
4917 		 * We found a valid overlapping pa but couldn't use it because
4918 		 * it had no free blocks. This should ideally never happen
4919 		 * because:
4920 		 *
4921 		 * 1. When a new inode pa is added to rbtree it must have
4922 		 *    pa_free > 0 since otherwise we won't actually need
4923 		 *    preallocation.
4924 		 *
4925 		 * 2. An inode pa that is in the rbtree can only have it's
4926 		 *    pa_free become zero when another thread calls:
4927 		 *      ext4_mb_new_blocks
4928 		 *       ext4_mb_use_preallocated
4929 		 *        ext4_mb_use_inode_pa
4930 		 *
4931 		 * 3. Further, after the above calls make pa_free == 0, we will
4932 		 *    immediately remove it from the rbtree in:
4933 		 *      ext4_mb_new_blocks
4934 		 *       ext4_mb_release_context
4935 		 *        ext4_mb_put_pa
4936 		 *
4937 		 * 4. Since the pa_free becoming 0 and pa_free getting removed
4938 		 * from tree both happen in ext4_mb_new_blocks, which is always
4939 		 * called with i_data_sem held for data allocations, we can be
4940 		 * sure that another process will never see a pa in rbtree with
4941 		 * pa_free == 0.
4942 		 */
4943 		WARN_ON_ONCE(tmp_pa->pa_free == 0);
4944 	}
4945 	spin_unlock(&tmp_pa->pa_lock);
4946 try_group_pa:
4947 	read_unlock(&ei->i_prealloc_lock);
4948 
4949 	/* can we use group allocation? */
4950 	if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
4951 		return false;
4952 
4953 	/* inode may have no locality group for some reason */
4954 	lg = ac->ac_lg;
4955 	if (lg == NULL)
4956 		return false;
4957 	order  = fls(ac->ac_o_ex.fe_len) - 1;
4958 	if (order > PREALLOC_TB_SIZE - 1)
4959 		/* The max size of hash table is PREALLOC_TB_SIZE */
4960 		order = PREALLOC_TB_SIZE - 1;
4961 
4962 	goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
4963 	/*
4964 	 * search for the prealloc space that is having
4965 	 * minimal distance from the goal block.
4966 	 */
4967 	for (i = order; i < PREALLOC_TB_SIZE; i++) {
4968 		rcu_read_lock();
4969 		list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[i],
4970 					pa_node.lg_list) {
4971 			spin_lock(&tmp_pa->pa_lock);
4972 			if (tmp_pa->pa_deleted == 0 &&
4973 					tmp_pa->pa_free >= ac->ac_o_ex.fe_len) {
4974 
4975 				cpa = ext4_mb_check_group_pa(goal_block,
4976 								tmp_pa, cpa);
4977 			}
4978 			spin_unlock(&tmp_pa->pa_lock);
4979 		}
4980 		rcu_read_unlock();
4981 	}
4982 	if (cpa) {
4983 		ext4_mb_use_group_pa(ac, cpa);
4984 		return true;
4985 	}
4986 	return false;
4987 }
4988 
4989 /*
4990  * the function goes through all preallocation in this group and marks them
4991  * used in in-core bitmap. buddy must be generated from this bitmap
4992  * Need to be called with ext4 group lock held
4993  */
4994 static noinline_for_stack
ext4_mb_generate_from_pa(struct super_block * sb,void * bitmap,ext4_group_t group)4995 void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
4996 					ext4_group_t group)
4997 {
4998 	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
4999 	struct ext4_prealloc_space *pa;
5000 	struct list_head *cur;
5001 	ext4_group_t groupnr;
5002 	ext4_grpblk_t start;
5003 	int preallocated = 0;
5004 	int len;
5005 
5006 	if (!grp)
5007 		return;
5008 
5009 	/* all form of preallocation discards first load group,
5010 	 * so the only competing code is preallocation use.
5011 	 * we don't need any locking here
5012 	 * notice we do NOT ignore preallocations with pa_deleted
5013 	 * otherwise we could leave used blocks available for
5014 	 * allocation in buddy when concurrent ext4_mb_put_pa()
5015 	 * is dropping preallocation
5016 	 */
5017 	list_for_each(cur, &grp->bb_prealloc_list) {
5018 		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
5019 		spin_lock(&pa->pa_lock);
5020 		ext4_get_group_no_and_offset(sb, pa->pa_pstart,
5021 					     &groupnr, &start);
5022 		len = pa->pa_len;
5023 		spin_unlock(&pa->pa_lock);
5024 		if (unlikely(len == 0))
5025 			continue;
5026 		BUG_ON(groupnr != group);
5027 		mb_set_bits(bitmap, start, len);
5028 		preallocated += len;
5029 	}
5030 	mb_debug(sb, "preallocated %d for group %u\n", preallocated, group);
5031 }
5032 
ext4_mb_mark_pa_deleted(struct super_block * sb,struct ext4_prealloc_space * pa)5033 static void ext4_mb_mark_pa_deleted(struct super_block *sb,
5034 				    struct ext4_prealloc_space *pa)
5035 {
5036 	struct ext4_inode_info *ei;
5037 
5038 	if (pa->pa_deleted) {
5039 		ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n",
5040 			     pa->pa_type, pa->pa_pstart, pa->pa_lstart,
5041 			     pa->pa_len);
5042 		return;
5043 	}
5044 
5045 	pa->pa_deleted = 1;
5046 
5047 	if (pa->pa_type == MB_INODE_PA) {
5048 		ei = EXT4_I(pa->pa_inode);
5049 		atomic_dec(&ei->i_prealloc_active);
5050 	}
5051 }
5052 
ext4_mb_pa_free(struct ext4_prealloc_space * pa)5053 static inline void ext4_mb_pa_free(struct ext4_prealloc_space *pa)
5054 {
5055 	BUG_ON(!pa);
5056 	BUG_ON(atomic_read(&pa->pa_count));
5057 	BUG_ON(pa->pa_deleted == 0);
5058 	kmem_cache_free(ext4_pspace_cachep, pa);
5059 }
5060 
ext4_mb_pa_callback(struct rcu_head * head)5061 static void ext4_mb_pa_callback(struct rcu_head *head)
5062 {
5063 	struct ext4_prealloc_space *pa;
5064 
5065 	pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
5066 	ext4_mb_pa_free(pa);
5067 }
5068 
5069 /*
5070  * drops a reference to preallocated space descriptor
5071  * if this was the last reference and the space is consumed
5072  */
ext4_mb_put_pa(struct ext4_allocation_context * ac,struct super_block * sb,struct ext4_prealloc_space * pa)5073 static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
5074 			struct super_block *sb, struct ext4_prealloc_space *pa)
5075 {
5076 	ext4_group_t grp;
5077 	ext4_fsblk_t grp_blk;
5078 	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
5079 
5080 	/* in this short window concurrent discard can set pa_deleted */
5081 	spin_lock(&pa->pa_lock);
5082 	if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
5083 		spin_unlock(&pa->pa_lock);
5084 		return;
5085 	}
5086 
5087 	if (pa->pa_deleted == 1) {
5088 		spin_unlock(&pa->pa_lock);
5089 		return;
5090 	}
5091 
5092 	ext4_mb_mark_pa_deleted(sb, pa);
5093 	spin_unlock(&pa->pa_lock);
5094 
5095 	grp_blk = pa->pa_pstart;
5096 	/*
5097 	 * If doing group-based preallocation, pa_pstart may be in the
5098 	 * next group when pa is used up
5099 	 */
5100 	if (pa->pa_type == MB_GROUP_PA)
5101 		grp_blk--;
5102 
5103 	grp = ext4_get_group_number(sb, grp_blk);
5104 
5105 	/*
5106 	 * possible race:
5107 	 *
5108 	 *  P1 (buddy init)			P2 (regular allocation)
5109 	 *					find block B in PA
5110 	 *  copy on-disk bitmap to buddy
5111 	 *  					mark B in on-disk bitmap
5112 	 *					drop PA from group
5113 	 *  mark all PAs in buddy
5114 	 *
5115 	 * thus, P1 initializes buddy with B available. to prevent this
5116 	 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
5117 	 * against that pair
5118 	 */
5119 	ext4_lock_group(sb, grp);
5120 	list_del(&pa->pa_group_list);
5121 	ext4_unlock_group(sb, grp);
5122 
5123 	if (pa->pa_type == MB_INODE_PA) {
5124 		write_lock(pa->pa_node_lock.inode_lock);
5125 		rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
5126 		write_unlock(pa->pa_node_lock.inode_lock);
5127 		ext4_mb_pa_free(pa);
5128 	} else {
5129 		spin_lock(pa->pa_node_lock.lg_lock);
5130 		list_del_rcu(&pa->pa_node.lg_list);
5131 		spin_unlock(pa->pa_node_lock.lg_lock);
5132 		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
5133 	}
5134 }
5135 
ext4_mb_pa_rb_insert(struct rb_root * root,struct rb_node * new)5136 static void ext4_mb_pa_rb_insert(struct rb_root *root, struct rb_node *new)
5137 {
5138 	struct rb_node **iter = &root->rb_node, *parent = NULL;
5139 	struct ext4_prealloc_space *iter_pa, *new_pa;
5140 	ext4_lblk_t iter_start, new_start;
5141 
5142 	while (*iter) {
5143 		iter_pa = rb_entry(*iter, struct ext4_prealloc_space,
5144 				   pa_node.inode_node);
5145 		new_pa = rb_entry(new, struct ext4_prealloc_space,
5146 				   pa_node.inode_node);
5147 		iter_start = iter_pa->pa_lstart;
5148 		new_start = new_pa->pa_lstart;
5149 
5150 		parent = *iter;
5151 		if (new_start < iter_start)
5152 			iter = &((*iter)->rb_left);
5153 		else
5154 			iter = &((*iter)->rb_right);
5155 	}
5156 
5157 	rb_link_node(new, parent, iter);
5158 	rb_insert_color(new, root);
5159 }
5160 
5161 /*
5162  * creates new preallocated space for given inode
5163  */
5164 static noinline_for_stack void
ext4_mb_new_inode_pa(struct ext4_allocation_context * ac)5165 ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
5166 {
5167 	struct super_block *sb = ac->ac_sb;
5168 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5169 	struct ext4_prealloc_space *pa;
5170 	struct ext4_group_info *grp;
5171 	struct ext4_inode_info *ei;
5172 
5173 	/* preallocate only when found space is larger then requested */
5174 	BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
5175 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
5176 	BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
5177 	BUG_ON(ac->ac_pa == NULL);
5178 
5179 	pa = ac->ac_pa;
5180 
5181 	if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) {
5182 		struct ext4_free_extent ex = {
5183 			.fe_logical = ac->ac_g_ex.fe_logical,
5184 			.fe_len = ac->ac_orig_goal_len,
5185 		};
5186 		loff_t orig_goal_end = extent_logical_end(sbi, &ex);
5187 
5188 		/* we can't allocate as much as normalizer wants.
5189 		 * so, found space must get proper lstart
5190 		 * to cover original request */
5191 		BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
5192 		BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
5193 
5194 		/*
5195 		 * Use the below logic for adjusting best extent as it keeps
5196 		 * fragmentation in check while ensuring logical range of best
5197 		 * extent doesn't overflow out of goal extent:
5198 		 *
5199 		 * 1. Check if best ex can be kept at end of goal (before
5200 		 *    cr_best_avail trimmed it) and still cover original start
5201 		 * 2. Else, check if best ex can be kept at start of goal and
5202 		 *    still cover original start
5203 		 * 3. Else, keep the best ex at start of original request.
5204 		 */
5205 		ex.fe_len = ac->ac_b_ex.fe_len;
5206 
5207 		ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len);
5208 		if (ac->ac_o_ex.fe_logical >= ex.fe_logical)
5209 			goto adjust_bex;
5210 
5211 		ex.fe_logical = ac->ac_g_ex.fe_logical;
5212 		if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex))
5213 			goto adjust_bex;
5214 
5215 		ex.fe_logical = ac->ac_o_ex.fe_logical;
5216 adjust_bex:
5217 		ac->ac_b_ex.fe_logical = ex.fe_logical;
5218 
5219 		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
5220 		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
5221 		BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
5222 	}
5223 
5224 	pa->pa_lstart = ac->ac_b_ex.fe_logical;
5225 	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
5226 	pa->pa_len = ac->ac_b_ex.fe_len;
5227 	pa->pa_free = pa->pa_len;
5228 	spin_lock_init(&pa->pa_lock);
5229 	INIT_LIST_HEAD(&pa->pa_group_list);
5230 	pa->pa_deleted = 0;
5231 	pa->pa_type = MB_INODE_PA;
5232 
5233 	mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
5234 		 pa->pa_len, pa->pa_lstart);
5235 	trace_ext4_mb_new_inode_pa(ac, pa);
5236 
5237 	atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
5238 	ext4_mb_use_inode_pa(ac, pa);
5239 
5240 	ei = EXT4_I(ac->ac_inode);
5241 	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
5242 	if (!grp)
5243 		return;
5244 
5245 	pa->pa_node_lock.inode_lock = &ei->i_prealloc_lock;
5246 	pa->pa_inode = ac->ac_inode;
5247 
5248 	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
5249 
5250 	write_lock(pa->pa_node_lock.inode_lock);
5251 	ext4_mb_pa_rb_insert(&ei->i_prealloc_node, &pa->pa_node.inode_node);
5252 	write_unlock(pa->pa_node_lock.inode_lock);
5253 	atomic_inc(&ei->i_prealloc_active);
5254 }
5255 
5256 /*
5257  * creates new preallocated space for locality group inodes belongs to
5258  */
5259 static noinline_for_stack void
ext4_mb_new_group_pa(struct ext4_allocation_context * ac)5260 ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
5261 {
5262 	struct super_block *sb = ac->ac_sb;
5263 	struct ext4_locality_group *lg;
5264 	struct ext4_prealloc_space *pa;
5265 	struct ext4_group_info *grp;
5266 
5267 	/* preallocate only when found space is larger then requested */
5268 	BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
5269 	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
5270 	BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
5271 	BUG_ON(ac->ac_pa == NULL);
5272 
5273 	pa = ac->ac_pa;
5274 
5275 	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
5276 	pa->pa_lstart = pa->pa_pstart;
5277 	pa->pa_len = ac->ac_b_ex.fe_len;
5278 	pa->pa_free = pa->pa_len;
5279 	spin_lock_init(&pa->pa_lock);
5280 	INIT_LIST_HEAD(&pa->pa_node.lg_list);
5281 	INIT_LIST_HEAD(&pa->pa_group_list);
5282 	pa->pa_deleted = 0;
5283 	pa->pa_type = MB_GROUP_PA;
5284 
5285 	mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
5286 		 pa->pa_len, pa->pa_lstart);
5287 	trace_ext4_mb_new_group_pa(ac, pa);
5288 
5289 	ext4_mb_use_group_pa(ac, pa);
5290 	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
5291 
5292 	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
5293 	if (!grp)
5294 		return;
5295 	lg = ac->ac_lg;
5296 	BUG_ON(lg == NULL);
5297 
5298 	pa->pa_node_lock.lg_lock = &lg->lg_prealloc_lock;
5299 	pa->pa_inode = NULL;
5300 
5301 	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
5302 
5303 	/*
5304 	 * We will later add the new pa to the right bucket
5305 	 * after updating the pa_free in ext4_mb_release_context
5306 	 */
5307 }
5308 
ext4_mb_new_preallocation(struct ext4_allocation_context * ac)5309 static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
5310 {
5311 	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
5312 		ext4_mb_new_group_pa(ac);
5313 	else
5314 		ext4_mb_new_inode_pa(ac);
5315 }
5316 
5317 /*
5318  * finds all unused blocks in on-disk bitmap, frees them in
5319  * in-core bitmap and buddy.
5320  * @pa must be unlinked from inode and group lists, so that
5321  * nobody else can find/use it.
5322  * the caller MUST hold group/inode locks.
5323  * TODO: optimize the case when there are no in-core structures yet
5324  */
5325 static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy * e4b,struct buffer_head * bitmap_bh,struct ext4_prealloc_space * pa)5326 ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
5327 			struct ext4_prealloc_space *pa)
5328 {
5329 	struct super_block *sb = e4b->bd_sb;
5330 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5331 	unsigned int end;
5332 	unsigned int next;
5333 	ext4_group_t group;
5334 	ext4_grpblk_t bit;
5335 	unsigned long long grp_blk_start;
5336 	int free = 0;
5337 
5338 	BUG_ON(pa->pa_deleted == 0);
5339 	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
5340 	grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
5341 	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
5342 	end = bit + pa->pa_len;
5343 
5344 	while (bit < end) {
5345 		bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
5346 		if (bit >= end)
5347 			break;
5348 		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
5349 		mb_debug(sb, "free preallocated %u/%u in group %u\n",
5350 			 (unsigned) ext4_group_first_block_no(sb, group) + bit,
5351 			 (unsigned) next - bit, (unsigned) group);
5352 		free += next - bit;
5353 
5354 		trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
5355 		trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
5356 						    EXT4_C2B(sbi, bit)),
5357 					       next - bit);
5358 		mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
5359 		bit = next + 1;
5360 	}
5361 	if (free != pa->pa_free) {
5362 		ext4_msg(e4b->bd_sb, KERN_CRIT,
5363 			 "pa %p: logic %lu, phys. %lu, len %d",
5364 			 pa, (unsigned long) pa->pa_lstart,
5365 			 (unsigned long) pa->pa_pstart,
5366 			 pa->pa_len);
5367 		ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
5368 					free, pa->pa_free);
5369 		/*
5370 		 * pa is already deleted so we use the value obtained
5371 		 * from the bitmap and continue.
5372 		 */
5373 	}
5374 	atomic_add(free, &sbi->s_mb_discarded);
5375 
5376 	return 0;
5377 }
5378 
5379 static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy * e4b,struct ext4_prealloc_space * pa)5380 ext4_mb_release_group_pa(struct ext4_buddy *e4b,
5381 				struct ext4_prealloc_space *pa)
5382 {
5383 	struct super_block *sb = e4b->bd_sb;
5384 	ext4_group_t group;
5385 	ext4_grpblk_t bit;
5386 
5387 	trace_ext4_mb_release_group_pa(sb, pa);
5388 	BUG_ON(pa->pa_deleted == 0);
5389 	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
5390 	if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) {
5391 		ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu",
5392 			     e4b->bd_group, group, pa->pa_pstart);
5393 		return 0;
5394 	}
5395 	mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
5396 	atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
5397 	trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
5398 
5399 	return 0;
5400 }
5401 
5402 /*
5403  * releases all preallocations in given group
5404  *
5405  * first, we need to decide discard policy:
5406  * - when do we discard
5407  *   1) ENOSPC
5408  * - how many do we discard
5409  *   1) how many requested
5410  */
5411 static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block * sb,ext4_group_t group,int * busy)5412 ext4_mb_discard_group_preallocations(struct super_block *sb,
5413 				     ext4_group_t group, int *busy)
5414 {
5415 	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
5416 	struct buffer_head *bitmap_bh = NULL;
5417 	struct ext4_prealloc_space *pa, *tmp;
5418 	LIST_HEAD(list);
5419 	struct ext4_buddy e4b;
5420 	struct ext4_inode_info *ei;
5421 	int err;
5422 	int free = 0;
5423 
5424 	if (!grp)
5425 		return 0;
5426 	mb_debug(sb, "discard preallocation for group %u\n", group);
5427 	if (list_empty(&grp->bb_prealloc_list))
5428 		goto out_dbg;
5429 
5430 	bitmap_bh = ext4_read_block_bitmap(sb, group);
5431 	if (IS_ERR(bitmap_bh)) {
5432 		err = PTR_ERR(bitmap_bh);
5433 		ext4_error_err(sb, -err,
5434 			       "Error %d reading block bitmap for %u",
5435 			       err, group);
5436 		goto out_dbg;
5437 	}
5438 
5439 	err = ext4_mb_load_buddy(sb, group, &e4b);
5440 	if (err) {
5441 		ext4_warning(sb, "Error %d loading buddy information for %u",
5442 			     err, group);
5443 		put_bh(bitmap_bh);
5444 		goto out_dbg;
5445 	}
5446 
5447 	ext4_lock_group(sb, group);
5448 	list_for_each_entry_safe(pa, tmp,
5449 				&grp->bb_prealloc_list, pa_group_list) {
5450 		spin_lock(&pa->pa_lock);
5451 		if (atomic_read(&pa->pa_count)) {
5452 			spin_unlock(&pa->pa_lock);
5453 			*busy = 1;
5454 			continue;
5455 		}
5456 		if (pa->pa_deleted) {
5457 			spin_unlock(&pa->pa_lock);
5458 			continue;
5459 		}
5460 
5461 		/* seems this one can be freed ... */
5462 		ext4_mb_mark_pa_deleted(sb, pa);
5463 
5464 		if (!free)
5465 			this_cpu_inc(discard_pa_seq);
5466 
5467 		/* we can trust pa_free ... */
5468 		free += pa->pa_free;
5469 
5470 		spin_unlock(&pa->pa_lock);
5471 
5472 		list_del(&pa->pa_group_list);
5473 		list_add(&pa->u.pa_tmp_list, &list);
5474 	}
5475 
5476 	/* now free all selected PAs */
5477 	list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
5478 
5479 		/* remove from object (inode or locality group) */
5480 		if (pa->pa_type == MB_GROUP_PA) {
5481 			spin_lock(pa->pa_node_lock.lg_lock);
5482 			list_del_rcu(&pa->pa_node.lg_list);
5483 			spin_unlock(pa->pa_node_lock.lg_lock);
5484 		} else {
5485 			write_lock(pa->pa_node_lock.inode_lock);
5486 			ei = EXT4_I(pa->pa_inode);
5487 			rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
5488 			write_unlock(pa->pa_node_lock.inode_lock);
5489 		}
5490 
5491 		list_del(&pa->u.pa_tmp_list);
5492 
5493 		if (pa->pa_type == MB_GROUP_PA) {
5494 			ext4_mb_release_group_pa(&e4b, pa);
5495 			call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
5496 		} else {
5497 			ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
5498 			ext4_mb_pa_free(pa);
5499 		}
5500 	}
5501 
5502 	ext4_unlock_group(sb, group);
5503 	ext4_mb_unload_buddy(&e4b);
5504 	put_bh(bitmap_bh);
5505 out_dbg:
5506 	mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
5507 		 free, group, grp->bb_free);
5508 	return free;
5509 }
5510 
5511 /*
5512  * releases all non-used preallocated blocks for given inode
5513  *
5514  * It's important to discard preallocations under i_data_sem
5515  * We don't want another block to be served from the prealloc
5516  * space when we are discarding the inode prealloc space.
5517  *
5518  * FIXME!! Make sure it is valid at all the call sites
5519  */
ext4_discard_preallocations(struct inode * inode,unsigned int needed)5520 void ext4_discard_preallocations(struct inode *inode, unsigned int needed)
5521 {
5522 	struct ext4_inode_info *ei = EXT4_I(inode);
5523 	struct super_block *sb = inode->i_sb;
5524 	struct buffer_head *bitmap_bh = NULL;
5525 	struct ext4_prealloc_space *pa, *tmp;
5526 	ext4_group_t group = 0;
5527 	LIST_HEAD(list);
5528 	struct ext4_buddy e4b;
5529 	struct rb_node *iter;
5530 	int err;
5531 
5532 	if (!S_ISREG(inode->i_mode)) {
5533 		return;
5534 	}
5535 
5536 	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
5537 		return;
5538 
5539 	mb_debug(sb, "discard preallocation for inode %lu\n",
5540 		 inode->i_ino);
5541 	trace_ext4_discard_preallocations(inode,
5542 			atomic_read(&ei->i_prealloc_active), needed);
5543 
5544 	if (needed == 0)
5545 		needed = UINT_MAX;
5546 
5547 repeat:
5548 	/* first, collect all pa's in the inode */
5549 	write_lock(&ei->i_prealloc_lock);
5550 	for (iter = rb_first(&ei->i_prealloc_node); iter && needed;
5551 	     iter = rb_next(iter)) {
5552 		pa = rb_entry(iter, struct ext4_prealloc_space,
5553 			      pa_node.inode_node);
5554 		BUG_ON(pa->pa_node_lock.inode_lock != &ei->i_prealloc_lock);
5555 
5556 		spin_lock(&pa->pa_lock);
5557 		if (atomic_read(&pa->pa_count)) {
5558 			/* this shouldn't happen often - nobody should
5559 			 * use preallocation while we're discarding it */
5560 			spin_unlock(&pa->pa_lock);
5561 			write_unlock(&ei->i_prealloc_lock);
5562 			ext4_msg(sb, KERN_ERR,
5563 				 "uh-oh! used pa while discarding");
5564 			WARN_ON(1);
5565 			schedule_timeout_uninterruptible(HZ);
5566 			goto repeat;
5567 
5568 		}
5569 		if (pa->pa_deleted == 0) {
5570 			ext4_mb_mark_pa_deleted(sb, pa);
5571 			spin_unlock(&pa->pa_lock);
5572 			rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
5573 			list_add(&pa->u.pa_tmp_list, &list);
5574 			needed--;
5575 			continue;
5576 		}
5577 
5578 		/* someone is deleting pa right now */
5579 		spin_unlock(&pa->pa_lock);
5580 		write_unlock(&ei->i_prealloc_lock);
5581 
5582 		/* we have to wait here because pa_deleted
5583 		 * doesn't mean pa is already unlinked from
5584 		 * the list. as we might be called from
5585 		 * ->clear_inode() the inode will get freed
5586 		 * and concurrent thread which is unlinking
5587 		 * pa from inode's list may access already
5588 		 * freed memory, bad-bad-bad */
5589 
5590 		/* XXX: if this happens too often, we can
5591 		 * add a flag to force wait only in case
5592 		 * of ->clear_inode(), but not in case of
5593 		 * regular truncate */
5594 		schedule_timeout_uninterruptible(HZ);
5595 		goto repeat;
5596 	}
5597 	write_unlock(&ei->i_prealloc_lock);
5598 
5599 	list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
5600 		BUG_ON(pa->pa_type != MB_INODE_PA);
5601 		group = ext4_get_group_number(sb, pa->pa_pstart);
5602 
5603 		err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
5604 					     GFP_NOFS|__GFP_NOFAIL);
5605 		if (err) {
5606 			ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
5607 				       err, group);
5608 			continue;
5609 		}
5610 
5611 		bitmap_bh = ext4_read_block_bitmap(sb, group);
5612 		if (IS_ERR(bitmap_bh)) {
5613 			err = PTR_ERR(bitmap_bh);
5614 			ext4_error_err(sb, -err, "Error %d reading block bitmap for %u",
5615 				       err, group);
5616 			ext4_mb_unload_buddy(&e4b);
5617 			continue;
5618 		}
5619 
5620 		ext4_lock_group(sb, group);
5621 		list_del(&pa->pa_group_list);
5622 		ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
5623 		ext4_unlock_group(sb, group);
5624 
5625 		ext4_mb_unload_buddy(&e4b);
5626 		put_bh(bitmap_bh);
5627 
5628 		list_del(&pa->u.pa_tmp_list);
5629 		ext4_mb_pa_free(pa);
5630 	}
5631 }
5632 
ext4_mb_pa_alloc(struct ext4_allocation_context * ac)5633 static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac)
5634 {
5635 	struct ext4_prealloc_space *pa;
5636 
5637 	BUG_ON(ext4_pspace_cachep == NULL);
5638 	pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS);
5639 	if (!pa)
5640 		return -ENOMEM;
5641 	atomic_set(&pa->pa_count, 1);
5642 	ac->ac_pa = pa;
5643 	return 0;
5644 }
5645 
ext4_mb_pa_put_free(struct ext4_allocation_context * ac)5646 static void ext4_mb_pa_put_free(struct ext4_allocation_context *ac)
5647 {
5648 	struct ext4_prealloc_space *pa = ac->ac_pa;
5649 
5650 	BUG_ON(!pa);
5651 	ac->ac_pa = NULL;
5652 	WARN_ON(!atomic_dec_and_test(&pa->pa_count));
5653 	/*
5654 	 * current function is only called due to an error or due to
5655 	 * len of found blocks < len of requested blocks hence the PA has not
5656 	 * been added to grp->bb_prealloc_list. So we don't need to lock it
5657 	 */
5658 	pa->pa_deleted = 1;
5659 	ext4_mb_pa_free(pa);
5660 }
5661 
5662 #ifdef CONFIG_EXT4_DEBUG
ext4_mb_show_pa(struct super_block * sb)5663 static inline void ext4_mb_show_pa(struct super_block *sb)
5664 {
5665 	ext4_group_t i, ngroups;
5666 
5667 	if (ext4_forced_shutdown(sb))
5668 		return;
5669 
5670 	ngroups = ext4_get_groups_count(sb);
5671 	mb_debug(sb, "groups: ");
5672 	for (i = 0; i < ngroups; i++) {
5673 		struct ext4_group_info *grp = ext4_get_group_info(sb, i);
5674 		struct ext4_prealloc_space *pa;
5675 		ext4_grpblk_t start;
5676 		struct list_head *cur;
5677 
5678 		if (!grp)
5679 			continue;
5680 		ext4_lock_group(sb, i);
5681 		list_for_each(cur, &grp->bb_prealloc_list) {
5682 			pa = list_entry(cur, struct ext4_prealloc_space,
5683 					pa_group_list);
5684 			spin_lock(&pa->pa_lock);
5685 			ext4_get_group_no_and_offset(sb, pa->pa_pstart,
5686 						     NULL, &start);
5687 			spin_unlock(&pa->pa_lock);
5688 			mb_debug(sb, "PA:%u:%d:%d\n", i, start,
5689 				 pa->pa_len);
5690 		}
5691 		ext4_unlock_group(sb, i);
5692 		mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free,
5693 			 grp->bb_fragments);
5694 	}
5695 }
5696 
ext4_mb_show_ac(struct ext4_allocation_context * ac)5697 static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
5698 {
5699 	struct super_block *sb = ac->ac_sb;
5700 
5701 	if (ext4_forced_shutdown(sb))
5702 		return;
5703 
5704 	mb_debug(sb, "Can't allocate:"
5705 			" Allocation context details:");
5706 	mb_debug(sb, "status %u flags 0x%x",
5707 			ac->ac_status, ac->ac_flags);
5708 	mb_debug(sb, "orig %lu/%lu/%lu@%lu, "
5709 			"goal %lu/%lu/%lu@%lu, "
5710 			"best %lu/%lu/%lu@%lu cr %d",
5711 			(unsigned long)ac->ac_o_ex.fe_group,
5712 			(unsigned long)ac->ac_o_ex.fe_start,
5713 			(unsigned long)ac->ac_o_ex.fe_len,
5714 			(unsigned long)ac->ac_o_ex.fe_logical,
5715 			(unsigned long)ac->ac_g_ex.fe_group,
5716 			(unsigned long)ac->ac_g_ex.fe_start,
5717 			(unsigned long)ac->ac_g_ex.fe_len,
5718 			(unsigned long)ac->ac_g_ex.fe_logical,
5719 			(unsigned long)ac->ac_b_ex.fe_group,
5720 			(unsigned long)ac->ac_b_ex.fe_start,
5721 			(unsigned long)ac->ac_b_ex.fe_len,
5722 			(unsigned long)ac->ac_b_ex.fe_logical,
5723 			(int)ac->ac_criteria);
5724 	mb_debug(sb, "%u found", ac->ac_found);
5725 	mb_debug(sb, "used pa: %s, ", ac->ac_pa ? "yes" : "no");
5726 	if (ac->ac_pa)
5727 		mb_debug(sb, "pa_type %s\n", ac->ac_pa->pa_type == MB_GROUP_PA ?
5728 			 "group pa" : "inode pa");
5729 	ext4_mb_show_pa(sb);
5730 }
5731 #else
ext4_mb_show_pa(struct super_block * sb)5732 static inline void ext4_mb_show_pa(struct super_block *sb)
5733 {
5734 }
ext4_mb_show_ac(struct ext4_allocation_context * ac)5735 static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
5736 {
5737 	ext4_mb_show_pa(ac->ac_sb);
5738 }
5739 #endif
5740 
5741 /*
5742  * We use locality group preallocation for small size file. The size of the
5743  * file is determined by the current size or the resulting size after
5744  * allocation which ever is larger
5745  *
5746  * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
5747  */
ext4_mb_group_or_file(struct ext4_allocation_context * ac)5748 static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
5749 {
5750 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
5751 	int bsbits = ac->ac_sb->s_blocksize_bits;
5752 	loff_t size, isize;
5753 	bool inode_pa_eligible, group_pa_eligible;
5754 
5755 	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
5756 		return;
5757 
5758 	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
5759 		return;
5760 
5761 	group_pa_eligible = sbi->s_mb_group_prealloc > 0;
5762 	inode_pa_eligible = true;
5763 	size = extent_logical_end(sbi, &ac->ac_o_ex);
5764 	isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
5765 		>> bsbits;
5766 
5767 	/* No point in using inode preallocation for closed files */
5768 	if ((size == isize) && !ext4_fs_is_busy(sbi) &&
5769 	    !inode_is_open_for_write(ac->ac_inode))
5770 		inode_pa_eligible = false;
5771 
5772 	size = max(size, isize);
5773 	/* Don't use group allocation for large files */
5774 	if (size > sbi->s_mb_stream_request)
5775 		group_pa_eligible = false;
5776 
5777 	if (!group_pa_eligible) {
5778 		if (inode_pa_eligible)
5779 			ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
5780 		else
5781 			ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
5782 		return;
5783 	}
5784 
5785 	BUG_ON(ac->ac_lg != NULL);
5786 	/*
5787 	 * locality group prealloc space are per cpu. The reason for having
5788 	 * per cpu locality group is to reduce the contention between block
5789 	 * request from multiple CPUs.
5790 	 */
5791 	ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
5792 
5793 	/* we're going to use group allocation */
5794 	ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
5795 
5796 	/* serialize all allocations in the group */
5797 	mutex_lock(&ac->ac_lg->lg_mutex);
5798 }
5799 
5800 static noinline_for_stack void
ext4_mb_initialize_context(struct ext4_allocation_context * ac,struct ext4_allocation_request * ar)5801 ext4_mb_initialize_context(struct ext4_allocation_context *ac,
5802 				struct ext4_allocation_request *ar)
5803 {
5804 	struct super_block *sb = ar->inode->i_sb;
5805 	struct ext4_sb_info *sbi = EXT4_SB(sb);
5806 	struct ext4_super_block *es = sbi->s_es;
5807 	ext4_group_t group;
5808 	unsigned int len;
5809 	ext4_fsblk_t goal;
5810 	ext4_grpblk_t block;
5811 
5812 	/* we can't allocate > group size */
5813 	len = ar->len;
5814 
5815 	/* just a dirty hack to filter too big requests  */
5816 	if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
5817 		len = EXT4_CLUSTERS_PER_GROUP(sb);
5818 
5819 	/* start searching from the goal */
5820 	goal = ar->goal;
5821 	if (goal < le32_to_cpu(es->s_first_data_block) ||
5822 			goal >= ext4_blocks_count(es))
5823 		goal = le32_to_cpu(es->s_first_data_block);
5824 	ext4_get_group_no_and_offset(sb, goal, &group, &block);
5825 
5826 	/* set up allocation goals */
5827 	ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
5828 	ac->ac_status = AC_STATUS_CONTINUE;
5829 	ac->ac_sb = sb;
5830 	ac->ac_inode = ar->inode;
5831 	ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
5832 	ac->ac_o_ex.fe_group = group;
5833 	ac->ac_o_ex.fe_start = block;
5834 	ac->ac_o_ex.fe_len = len;
5835 	ac->ac_g_ex = ac->ac_o_ex;
5836 	ac->ac_orig_goal_len = ac->ac_g_ex.fe_len;
5837 	ac->ac_flags = ar->flags;
5838 
5839 	/* we have to define context: we'll work with a file or
5840 	 * locality group. this is a policy, actually */
5841 	ext4_mb_group_or_file(ac);
5842 
5843 	mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, "
5844 			"left: %u/%u, right %u/%u to %swritable\n",
5845 			(unsigned) ar->len, (unsigned) ar->logical,
5846 			(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
5847 			(unsigned) ar->lleft, (unsigned) ar->pleft,
5848 			(unsigned) ar->lright, (unsigned) ar->pright,
5849 			inode_is_open_for_write(ar->inode) ? "" : "non-");
5850 }
5851 
5852 static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block * sb,struct ext4_locality_group * lg,int order,int total_entries)5853 ext4_mb_discard_lg_preallocations(struct super_block *sb,
5854 					struct ext4_locality_group *lg,
5855 					int order, int total_entries)
5856 {
5857 	ext4_group_t group = 0;
5858 	struct ext4_buddy e4b;
5859 	LIST_HEAD(discard_list);
5860 	struct ext4_prealloc_space *pa, *tmp;
5861 
5862 	mb_debug(sb, "discard locality group preallocation\n");
5863 
5864 	spin_lock(&lg->lg_prealloc_lock);
5865 	list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
5866 				pa_node.lg_list,
5867 				lockdep_is_held(&lg->lg_prealloc_lock)) {
5868 		spin_lock(&pa->pa_lock);
5869 		if (atomic_read(&pa->pa_count)) {
5870 			/*
5871 			 * This is the pa that we just used
5872 			 * for block allocation. So don't
5873 			 * free that
5874 			 */
5875 			spin_unlock(&pa->pa_lock);
5876 			continue;
5877 		}
5878 		if (pa->pa_deleted) {
5879 			spin_unlock(&pa->pa_lock);
5880 			continue;
5881 		}
5882 		/* only lg prealloc space */
5883 		BUG_ON(pa->pa_type != MB_GROUP_PA);
5884 
5885 		/* seems this one can be freed ... */
5886 		ext4_mb_mark_pa_deleted(sb, pa);
5887 		spin_unlock(&pa->pa_lock);
5888 
5889 		list_del_rcu(&pa->pa_node.lg_list);
5890 		list_add(&pa->u.pa_tmp_list, &discard_list);
5891 
5892 		total_entries--;
5893 		if (total_entries <= 5) {
5894 			/*
5895 			 * we want to keep only 5 entries
5896 			 * allowing it to grow to 8. This
5897 			 * mak sure we don't call discard
5898 			 * soon for this list.
5899 			 */
5900 			break;
5901 		}
5902 	}
5903 	spin_unlock(&lg->lg_prealloc_lock);
5904 
5905 	list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
5906 		int err;
5907 
5908 		group = ext4_get_group_number(sb, pa->pa_pstart);
5909 		err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
5910 					     GFP_NOFS|__GFP_NOFAIL);
5911 		if (err) {
5912 			ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
5913 				       err, group);
5914 			continue;
5915 		}
5916 		ext4_lock_group(sb, group);
5917 		list_del(&pa->pa_group_list);
5918 		ext4_mb_release_group_pa(&e4b, pa);
5919 		ext4_unlock_group(sb, group);
5920 
5921 		ext4_mb_unload_buddy(&e4b);
5922 		list_del(&pa->u.pa_tmp_list);
5923 		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
5924 	}
5925 }
5926 
5927 /*
5928  * We have incremented pa_count. So it cannot be freed at this
5929  * point. Also we hold lg_mutex. So no parallel allocation is
5930  * possible from this lg. That means pa_free cannot be updated.
5931  *
5932  * A parallel ext4_mb_discard_group_preallocations is possible.
5933  * which can cause the lg_prealloc_list to be updated.
5934  */
5935 
ext4_mb_add_n_trim(struct ext4_allocation_context * ac)5936 static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
5937 {
5938 	int order, added = 0, lg_prealloc_count = 1;
5939 	struct super_block *sb = ac->ac_sb;
5940 	struct ext4_locality_group *lg = ac->ac_lg;
5941 	struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
5942 
5943 	order = fls(pa->pa_free) - 1;
5944 	if (order > PREALLOC_TB_SIZE - 1)
5945 		/* The max size of hash table is PREALLOC_TB_SIZE */
5946 		order = PREALLOC_TB_SIZE - 1;
5947 	/* Add the prealloc space to lg */
5948 	spin_lock(&lg->lg_prealloc_lock);
5949 	list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
5950 				pa_node.lg_list,
5951 				lockdep_is_held(&lg->lg_prealloc_lock)) {
5952 		spin_lock(&tmp_pa->pa_lock);
5953 		if (tmp_pa->pa_deleted) {
5954 			spin_unlock(&tmp_pa->pa_lock);
5955 			continue;
5956 		}
5957 		if (!added && pa->pa_free < tmp_pa->pa_free) {
5958 			/* Add to the tail of the previous entry */
5959 			list_add_tail_rcu(&pa->pa_node.lg_list,
5960 						&tmp_pa->pa_node.lg_list);
5961 			added = 1;
5962 			/*
5963 			 * we want to count the total
5964 			 * number of entries in the list
5965 			 */
5966 		}
5967 		spin_unlock(&tmp_pa->pa_lock);
5968 		lg_prealloc_count++;
5969 	}
5970 	if (!added)
5971 		list_add_tail_rcu(&pa->pa_node.lg_list,
5972 					&lg->lg_prealloc_list[order]);
5973 	spin_unlock(&lg->lg_prealloc_lock);
5974 
5975 	/* Now trim the list to be not more than 8 elements */
5976 	if (lg_prealloc_count > 8)
5977 		ext4_mb_discard_lg_preallocations(sb, lg,
5978 						  order, lg_prealloc_count);
5979 }
5980 
5981 /*
5982  * release all resource we used in allocation
5983  */
ext4_mb_release_context(struct ext4_allocation_context * ac)5984 static int ext4_mb_release_context(struct ext4_allocation_context *ac)
5985 {
5986 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
5987 	struct ext4_prealloc_space *pa = ac->ac_pa;
5988 	if (pa) {
5989 		if (pa->pa_type == MB_GROUP_PA) {
5990 			/* see comment in ext4_mb_use_group_pa() */
5991 			spin_lock(&pa->pa_lock);
5992 			pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
5993 			pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
5994 			pa->pa_free -= ac->ac_b_ex.fe_len;
5995 			pa->pa_len -= ac->ac_b_ex.fe_len;
5996 			spin_unlock(&pa->pa_lock);
5997 
5998 			/*
5999 			 * We want to add the pa to the right bucket.
6000 			 * Remove it from the list and while adding
6001 			 * make sure the list to which we are adding
6002 			 * doesn't grow big.
6003 			 */
6004 			if (likely(pa->pa_free)) {
6005 				spin_lock(pa->pa_node_lock.lg_lock);
6006 				list_del_rcu(&pa->pa_node.lg_list);
6007 				spin_unlock(pa->pa_node_lock.lg_lock);
6008 				ext4_mb_add_n_trim(ac);
6009 			}
6010 		}
6011 
6012 		ext4_mb_put_pa(ac, ac->ac_sb, pa);
6013 	}
6014 	if (ac->ac_bitmap_page)
6015 		put_page(ac->ac_bitmap_page);
6016 	if (ac->ac_buddy_page)
6017 		put_page(ac->ac_buddy_page);
6018 	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
6019 		mutex_unlock(&ac->ac_lg->lg_mutex);
6020 	ext4_mb_collect_stats(ac);
6021 	return 0;
6022 }
6023 
ext4_mb_discard_preallocations(struct super_block * sb,int needed)6024 static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
6025 {
6026 	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
6027 	int ret;
6028 	int freed = 0, busy = 0;
6029 	int retry = 0;
6030 
6031 	trace_ext4_mb_discard_preallocations(sb, needed);
6032 
6033 	if (needed == 0)
6034 		needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
6035  repeat:
6036 	for (i = 0; i < ngroups && needed > 0; i++) {
6037 		ret = ext4_mb_discard_group_preallocations(sb, i, &busy);
6038 		freed += ret;
6039 		needed -= ret;
6040 		cond_resched();
6041 	}
6042 
6043 	if (needed > 0 && busy && ++retry < 3) {
6044 		busy = 0;
6045 		goto repeat;
6046 	}
6047 
6048 	return freed;
6049 }
6050 
ext4_mb_discard_preallocations_should_retry(struct super_block * sb,struct ext4_allocation_context * ac,u64 * seq)6051 static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb,
6052 			struct ext4_allocation_context *ac, u64 *seq)
6053 {
6054 	int freed;
6055 	u64 seq_retry = 0;
6056 	bool ret = false;
6057 
6058 	freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
6059 	if (freed) {
6060 		ret = true;
6061 		goto out_dbg;
6062 	}
6063 	seq_retry = ext4_get_discard_pa_seq_sum();
6064 	if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) {
6065 		ac->ac_flags |= EXT4_MB_STRICT_CHECK;
6066 		*seq = seq_retry;
6067 		ret = true;
6068 	}
6069 
6070 out_dbg:
6071 	mb_debug(sb, "freed %d, retry ? %s\n", freed, ret ? "yes" : "no");
6072 	return ret;
6073 }
6074 
6075 /*
6076  * Simple allocator for Ext4 fast commit replay path. It searches for blocks
6077  * linearly starting at the goal block and also excludes the blocks which
6078  * are going to be in use after fast commit replay.
6079  */
6080 static ext4_fsblk_t
ext4_mb_new_blocks_simple(struct ext4_allocation_request * ar,int * errp)6081 ext4_mb_new_blocks_simple(struct ext4_allocation_request *ar, int *errp)
6082 {
6083 	struct buffer_head *bitmap_bh;
6084 	struct super_block *sb = ar->inode->i_sb;
6085 	struct ext4_sb_info *sbi = EXT4_SB(sb);
6086 	ext4_group_t group, nr;
6087 	ext4_grpblk_t blkoff;
6088 	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
6089 	ext4_grpblk_t i = 0;
6090 	ext4_fsblk_t goal, block;
6091 	struct ext4_super_block *es = sbi->s_es;
6092 
6093 	goal = ar->goal;
6094 	if (goal < le32_to_cpu(es->s_first_data_block) ||
6095 			goal >= ext4_blocks_count(es))
6096 		goal = le32_to_cpu(es->s_first_data_block);
6097 
6098 	ar->len = 0;
6099 	ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
6100 	for (nr = ext4_get_groups_count(sb); nr > 0; nr--) {
6101 		bitmap_bh = ext4_read_block_bitmap(sb, group);
6102 		if (IS_ERR(bitmap_bh)) {
6103 			*errp = PTR_ERR(bitmap_bh);
6104 			pr_warn("Failed to read block bitmap\n");
6105 			return 0;
6106 		}
6107 
6108 		while (1) {
6109 			i = mb_find_next_zero_bit(bitmap_bh->b_data, max,
6110 						blkoff);
6111 			if (i >= max)
6112 				break;
6113 			if (ext4_fc_replay_check_excluded(sb,
6114 				ext4_group_first_block_no(sb, group) +
6115 				EXT4_C2B(sbi, i))) {
6116 				blkoff = i + 1;
6117 			} else
6118 				break;
6119 		}
6120 		brelse(bitmap_bh);
6121 		if (i < max)
6122 			break;
6123 
6124 		if (++group >= ext4_get_groups_count(sb))
6125 			group = 0;
6126 
6127 		blkoff = 0;
6128 	}
6129 
6130 	if (i >= max) {
6131 		*errp = -ENOSPC;
6132 		return 0;
6133 	}
6134 
6135 	block = ext4_group_first_block_no(sb, group) + EXT4_C2B(sbi, i);
6136 	ext4_mb_mark_bb(sb, block, 1, 1);
6137 	ar->len = 1;
6138 
6139 	return block;
6140 }
6141 
6142 /*
6143  * Main entry point into mballoc to allocate blocks
6144  * it tries to use preallocation first, then falls back
6145  * to usual allocation
6146  */
ext4_mb_new_blocks(handle_t * handle,struct ext4_allocation_request * ar,int * errp)6147 ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
6148 				struct ext4_allocation_request *ar, int *errp)
6149 {
6150 	struct ext4_allocation_context *ac = NULL;
6151 	struct ext4_sb_info *sbi;
6152 	struct super_block *sb;
6153 	ext4_fsblk_t block = 0;
6154 	unsigned int inquota = 0;
6155 	unsigned int reserv_clstrs = 0;
6156 	int retries = 0;
6157 	u64 seq;
6158 
6159 	might_sleep();
6160 	sb = ar->inode->i_sb;
6161 	sbi = EXT4_SB(sb);
6162 
6163 	trace_ext4_request_blocks(ar);
6164 	if (sbi->s_mount_state & EXT4_FC_REPLAY)
6165 		return ext4_mb_new_blocks_simple(ar, errp);
6166 
6167 	/* Allow to use superuser reservation for quota file */
6168 	if (ext4_is_quota_file(ar->inode))
6169 		ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
6170 
6171 	if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
6172 		/* Without delayed allocation we need to verify
6173 		 * there is enough free blocks to do block allocation
6174 		 * and verify allocation doesn't exceed the quota limits.
6175 		 */
6176 		while (ar->len &&
6177 			ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
6178 
6179 			/* let others to free the space */
6180 			cond_resched();
6181 			ar->len = ar->len >> 1;
6182 		}
6183 		if (!ar->len) {
6184 			ext4_mb_show_pa(sb);
6185 			*errp = -ENOSPC;
6186 			return 0;
6187 		}
6188 		reserv_clstrs = ar->len;
6189 		if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
6190 			dquot_alloc_block_nofail(ar->inode,
6191 						 EXT4_C2B(sbi, ar->len));
6192 		} else {
6193 			while (ar->len &&
6194 				dquot_alloc_block(ar->inode,
6195 						  EXT4_C2B(sbi, ar->len))) {
6196 
6197 				ar->flags |= EXT4_MB_HINT_NOPREALLOC;
6198 				ar->len--;
6199 			}
6200 		}
6201 		inquota = ar->len;
6202 		if (ar->len == 0) {
6203 			*errp = -EDQUOT;
6204 			goto out;
6205 		}
6206 	}
6207 
6208 	ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
6209 	if (!ac) {
6210 		ar->len = 0;
6211 		*errp = -ENOMEM;
6212 		goto out;
6213 	}
6214 
6215 	ext4_mb_initialize_context(ac, ar);
6216 
6217 	ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
6218 	seq = this_cpu_read(discard_pa_seq);
6219 	if (!ext4_mb_use_preallocated(ac)) {
6220 		ac->ac_op = EXT4_MB_HISTORY_ALLOC;
6221 		ext4_mb_normalize_request(ac, ar);
6222 
6223 		*errp = ext4_mb_pa_alloc(ac);
6224 		if (*errp)
6225 			goto errout;
6226 repeat:
6227 		/* allocate space in core */
6228 		*errp = ext4_mb_regular_allocator(ac);
6229 		/*
6230 		 * pa allocated above is added to grp->bb_prealloc_list only
6231 		 * when we were able to allocate some block i.e. when
6232 		 * ac->ac_status == AC_STATUS_FOUND.
6233 		 * And error from above mean ac->ac_status != AC_STATUS_FOUND
6234 		 * So we have to free this pa here itself.
6235 		 */
6236 		if (*errp) {
6237 			ext4_mb_pa_put_free(ac);
6238 			ext4_discard_allocated_blocks(ac);
6239 			goto errout;
6240 		}
6241 		if (ac->ac_status == AC_STATUS_FOUND &&
6242 			ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len)
6243 			ext4_mb_pa_put_free(ac);
6244 	}
6245 	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
6246 		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
6247 		if (*errp) {
6248 			ext4_discard_allocated_blocks(ac);
6249 			goto errout;
6250 		} else {
6251 			block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
6252 			ar->len = ac->ac_b_ex.fe_len;
6253 		}
6254 	} else {
6255 		if (++retries < 3 &&
6256 		    ext4_mb_discard_preallocations_should_retry(sb, ac, &seq))
6257 			goto repeat;
6258 		/*
6259 		 * If block allocation fails then the pa allocated above
6260 		 * needs to be freed here itself.
6261 		 */
6262 		ext4_mb_pa_put_free(ac);
6263 		*errp = -ENOSPC;
6264 	}
6265 
6266 	if (*errp) {
6267 errout:
6268 		ac->ac_b_ex.fe_len = 0;
6269 		ar->len = 0;
6270 		ext4_mb_show_ac(ac);
6271 	}
6272 	ext4_mb_release_context(ac);
6273 	kmem_cache_free(ext4_ac_cachep, ac);
6274 out:
6275 	if (inquota && ar->len < inquota)
6276 		dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
6277 	if (!ar->len) {
6278 		if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
6279 			/* release all the reserved blocks if non delalloc */
6280 			percpu_counter_sub(&sbi->s_dirtyclusters_counter,
6281 						reserv_clstrs);
6282 	}
6283 
6284 	trace_ext4_allocate_blocks(ar, (unsigned long long)block);
6285 
6286 	return block;
6287 }
6288 
6289 /*
6290  * We can merge two free data extents only if the physical blocks
6291  * are contiguous, AND the extents were freed by the same transaction,
6292  * AND the blocks are associated with the same group.
6293  */
ext4_try_merge_freed_extent(struct ext4_sb_info * sbi,struct ext4_free_data * entry,struct ext4_free_data * new_entry,struct rb_root * entry_rb_root)6294 static void ext4_try_merge_freed_extent(struct ext4_sb_info *sbi,
6295 					struct ext4_free_data *entry,
6296 					struct ext4_free_data *new_entry,
6297 					struct rb_root *entry_rb_root)
6298 {
6299 	if ((entry->efd_tid != new_entry->efd_tid) ||
6300 	    (entry->efd_group != new_entry->efd_group))
6301 		return;
6302 	if (entry->efd_start_cluster + entry->efd_count ==
6303 	    new_entry->efd_start_cluster) {
6304 		new_entry->efd_start_cluster = entry->efd_start_cluster;
6305 		new_entry->efd_count += entry->efd_count;
6306 	} else if (new_entry->efd_start_cluster + new_entry->efd_count ==
6307 		   entry->efd_start_cluster) {
6308 		new_entry->efd_count += entry->efd_count;
6309 	} else
6310 		return;
6311 	spin_lock(&sbi->s_md_lock);
6312 	list_del(&entry->efd_list);
6313 	spin_unlock(&sbi->s_md_lock);
6314 	rb_erase(&entry->efd_node, entry_rb_root);
6315 	kmem_cache_free(ext4_free_data_cachep, entry);
6316 }
6317 
6318 static noinline_for_stack void
ext4_mb_free_metadata(handle_t * handle,struct ext4_buddy * e4b,struct ext4_free_data * new_entry)6319 ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
6320 		      struct ext4_free_data *new_entry)
6321 {
6322 	ext4_group_t group = e4b->bd_group;
6323 	ext4_grpblk_t cluster;
6324 	ext4_grpblk_t clusters = new_entry->efd_count;
6325 	struct ext4_free_data *entry;
6326 	struct ext4_group_info *db = e4b->bd_info;
6327 	struct super_block *sb = e4b->bd_sb;
6328 	struct ext4_sb_info *sbi = EXT4_SB(sb);
6329 	struct rb_node **n = &db->bb_free_root.rb_node, *node;
6330 	struct rb_node *parent = NULL, *new_node;
6331 
6332 	BUG_ON(!ext4_handle_valid(handle));
6333 	BUG_ON(e4b->bd_bitmap_page == NULL);
6334 	BUG_ON(e4b->bd_buddy_page == NULL);
6335 
6336 	new_node = &new_entry->efd_node;
6337 	cluster = new_entry->efd_start_cluster;
6338 
6339 	if (!*n) {
6340 		/* first free block exent. We need to
6341 		   protect buddy cache from being freed,
6342 		 * otherwise we'll refresh it from
6343 		 * on-disk bitmap and lose not-yet-available
6344 		 * blocks */
6345 		get_page(e4b->bd_buddy_page);
6346 		get_page(e4b->bd_bitmap_page);
6347 	}
6348 	while (*n) {
6349 		parent = *n;
6350 		entry = rb_entry(parent, struct ext4_free_data, efd_node);
6351 		if (cluster < entry->efd_start_cluster)
6352 			n = &(*n)->rb_left;
6353 		else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
6354 			n = &(*n)->rb_right;
6355 		else {
6356 			ext4_grp_locked_error(sb, group, 0,
6357 				ext4_group_first_block_no(sb, group) +
6358 				EXT4_C2B(sbi, cluster),
6359 				"Block already on to-be-freed list");
6360 			kmem_cache_free(ext4_free_data_cachep, new_entry);
6361 			return;
6362 		}
6363 	}
6364 
6365 	rb_link_node(new_node, parent, n);
6366 	rb_insert_color(new_node, &db->bb_free_root);
6367 
6368 	/* Now try to see the extent can be merged to left and right */
6369 	node = rb_prev(new_node);
6370 	if (node) {
6371 		entry = rb_entry(node, struct ext4_free_data, efd_node);
6372 		ext4_try_merge_freed_extent(sbi, entry, new_entry,
6373 					    &(db->bb_free_root));
6374 	}
6375 
6376 	node = rb_next(new_node);
6377 	if (node) {
6378 		entry = rb_entry(node, struct ext4_free_data, efd_node);
6379 		ext4_try_merge_freed_extent(sbi, entry, new_entry,
6380 					    &(db->bb_free_root));
6381 	}
6382 
6383 	spin_lock(&sbi->s_md_lock);
6384 	list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list);
6385 	sbi->s_mb_free_pending += clusters;
6386 	spin_unlock(&sbi->s_md_lock);
6387 }
6388 
ext4_free_blocks_simple(struct inode * inode,ext4_fsblk_t block,unsigned long count)6389 static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
6390 					unsigned long count)
6391 {
6392 	struct buffer_head *bitmap_bh;
6393 	struct super_block *sb = inode->i_sb;
6394 	struct ext4_group_desc *gdp;
6395 	struct buffer_head *gdp_bh;
6396 	ext4_group_t group;
6397 	ext4_grpblk_t blkoff;
6398 	int already_freed = 0, err, i;
6399 
6400 	ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
6401 	bitmap_bh = ext4_read_block_bitmap(sb, group);
6402 	if (IS_ERR(bitmap_bh)) {
6403 		pr_warn("Failed to read block bitmap\n");
6404 		return;
6405 	}
6406 	gdp = ext4_get_group_desc(sb, group, &gdp_bh);
6407 	if (!gdp)
6408 		goto err_out;
6409 
6410 	for (i = 0; i < count; i++) {
6411 		if (!mb_test_bit(blkoff + i, bitmap_bh->b_data))
6412 			already_freed++;
6413 	}
6414 	mb_clear_bits(bitmap_bh->b_data, blkoff, count);
6415 	err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
6416 	if (err)
6417 		goto err_out;
6418 	ext4_free_group_clusters_set(
6419 		sb, gdp, ext4_free_group_clusters(sb, gdp) +
6420 		count - already_freed);
6421 	ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
6422 	ext4_group_desc_csum_set(sb, group, gdp);
6423 	ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
6424 	sync_dirty_buffer(bitmap_bh);
6425 	sync_dirty_buffer(gdp_bh);
6426 
6427 err_out:
6428 	brelse(bitmap_bh);
6429 }
6430 
6431 /**
6432  * ext4_mb_clear_bb() -- helper function for freeing blocks.
6433  *			Used by ext4_free_blocks()
6434  * @handle:		handle for this transaction
6435  * @inode:		inode
6436  * @block:		starting physical block to be freed
6437  * @count:		number of blocks to be freed
6438  * @flags:		flags used by ext4_free_blocks
6439  */
ext4_mb_clear_bb(handle_t * handle,struct inode * inode,ext4_fsblk_t block,unsigned long count,int flags)6440 static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode,
6441 			       ext4_fsblk_t block, unsigned long count,
6442 			       int flags)
6443 {
6444 	struct buffer_head *bitmap_bh = NULL;
6445 	struct super_block *sb = inode->i_sb;
6446 	struct ext4_group_desc *gdp;
6447 	struct ext4_group_info *grp;
6448 	unsigned int overflow;
6449 	ext4_grpblk_t bit;
6450 	struct buffer_head *gd_bh;
6451 	ext4_group_t block_group;
6452 	struct ext4_sb_info *sbi;
6453 	struct ext4_buddy e4b;
6454 	unsigned int count_clusters;
6455 	int err = 0;
6456 	int ret;
6457 
6458 	sbi = EXT4_SB(sb);
6459 
6460 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
6461 	    !ext4_inode_block_valid(inode, block, count)) {
6462 		ext4_error(sb, "Freeing blocks in system zone - "
6463 			   "Block = %llu, count = %lu", block, count);
6464 		/* err = 0. ext4_std_error should be a no op */
6465 		goto error_return;
6466 	}
6467 	flags |= EXT4_FREE_BLOCKS_VALIDATED;
6468 
6469 do_more:
6470 	overflow = 0;
6471 	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
6472 
6473 	grp = ext4_get_group_info(sb, block_group);
6474 	if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
6475 		return;
6476 
6477 	/*
6478 	 * Check to see if we are freeing blocks across a group
6479 	 * boundary.
6480 	 */
6481 	if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
6482 		overflow = EXT4_C2B(sbi, bit) + count -
6483 			EXT4_BLOCKS_PER_GROUP(sb);
6484 		count -= overflow;
6485 		/* The range changed so it's no longer validated */
6486 		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
6487 	}
6488 	count_clusters = EXT4_NUM_B2C(sbi, count);
6489 	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
6490 	if (IS_ERR(bitmap_bh)) {
6491 		err = PTR_ERR(bitmap_bh);
6492 		bitmap_bh = NULL;
6493 		goto error_return;
6494 	}
6495 	gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
6496 	if (!gdp) {
6497 		err = -EIO;
6498 		goto error_return;
6499 	}
6500 
6501 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
6502 	    !ext4_inode_block_valid(inode, block, count)) {
6503 		ext4_error(sb, "Freeing blocks in system zone - "
6504 			   "Block = %llu, count = %lu", block, count);
6505 		/* err = 0. ext4_std_error should be a no op */
6506 		goto error_return;
6507 	}
6508 
6509 	BUFFER_TRACE(bitmap_bh, "getting write access");
6510 	err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
6511 					    EXT4_JTR_NONE);
6512 	if (err)
6513 		goto error_return;
6514 
6515 	/*
6516 	 * We are about to modify some metadata.  Call the journal APIs
6517 	 * to unshare ->b_data if a currently-committing transaction is
6518 	 * using it
6519 	 */
6520 	BUFFER_TRACE(gd_bh, "get_write_access");
6521 	err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
6522 	if (err)
6523 		goto error_return;
6524 #ifdef AGGRESSIVE_CHECK
6525 	{
6526 		int i;
6527 		for (i = 0; i < count_clusters; i++)
6528 			BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
6529 	}
6530 #endif
6531 	trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
6532 
6533 	/* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
6534 	err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
6535 				     GFP_NOFS|__GFP_NOFAIL);
6536 	if (err)
6537 		goto error_return;
6538 
6539 	/*
6540 	 * We need to make sure we don't reuse the freed block until after the
6541 	 * transaction is committed. We make an exception if the inode is to be
6542 	 * written in writeback mode since writeback mode has weak data
6543 	 * consistency guarantees.
6544 	 */
6545 	if (ext4_handle_valid(handle) &&
6546 	    ((flags & EXT4_FREE_BLOCKS_METADATA) ||
6547 	     !ext4_should_writeback_data(inode))) {
6548 		struct ext4_free_data *new_entry;
6549 		/*
6550 		 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
6551 		 * to fail.
6552 		 */
6553 		new_entry = kmem_cache_alloc(ext4_free_data_cachep,
6554 				GFP_NOFS|__GFP_NOFAIL);
6555 		new_entry->efd_start_cluster = bit;
6556 		new_entry->efd_group = block_group;
6557 		new_entry->efd_count = count_clusters;
6558 		new_entry->efd_tid = handle->h_transaction->t_tid;
6559 
6560 		ext4_lock_group(sb, block_group);
6561 		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
6562 		ext4_mb_free_metadata(handle, &e4b, new_entry);
6563 	} else {
6564 		/* need to update group_info->bb_free and bitmap
6565 		 * with group lock held. generate_buddy look at
6566 		 * them with group lock_held
6567 		 */
6568 		if (test_opt(sb, DISCARD)) {
6569 			err = ext4_issue_discard(sb, block_group, bit,
6570 						 count_clusters, NULL);
6571 			if (err && err != -EOPNOTSUPP)
6572 				ext4_msg(sb, KERN_WARNING, "discard request in"
6573 					 " group:%u block:%d count:%lu failed"
6574 					 " with %d", block_group, bit, count,
6575 					 err);
6576 		} else
6577 			EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
6578 
6579 		ext4_lock_group(sb, block_group);
6580 		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
6581 		mb_free_blocks(inode, &e4b, bit, count_clusters);
6582 	}
6583 
6584 	ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
6585 	ext4_free_group_clusters_set(sb, gdp, ret);
6586 	ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
6587 	ext4_group_desc_csum_set(sb, block_group, gdp);
6588 	ext4_unlock_group(sb, block_group);
6589 
6590 	if (sbi->s_log_groups_per_flex) {
6591 		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
6592 		atomic64_add(count_clusters,
6593 			     &sbi_array_rcu_deref(sbi, s_flex_groups,
6594 						  flex_group)->free_clusters);
6595 	}
6596 
6597 	/*
6598 	 * on a bigalloc file system, defer the s_freeclusters_counter
6599 	 * update to the caller (ext4_remove_space and friends) so they
6600 	 * can determine if a cluster freed here should be rereserved
6601 	 */
6602 	if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) {
6603 		if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
6604 			dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
6605 		percpu_counter_add(&sbi->s_freeclusters_counter,
6606 				   count_clusters);
6607 	}
6608 
6609 	ext4_mb_unload_buddy(&e4b);
6610 
6611 	/* We dirtied the bitmap block */
6612 	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
6613 	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
6614 
6615 	/* And the group descriptor block */
6616 	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
6617 	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
6618 	if (!err)
6619 		err = ret;
6620 
6621 	if (overflow && !err) {
6622 		block += count;
6623 		count = overflow;
6624 		put_bh(bitmap_bh);
6625 		/* The range changed so it's no longer validated */
6626 		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
6627 		goto do_more;
6628 	}
6629 error_return:
6630 	brelse(bitmap_bh);
6631 	ext4_std_error(sb, err);
6632 }
6633 
6634 /**
6635  * ext4_free_blocks() -- Free given blocks and update quota
6636  * @handle:		handle for this transaction
6637  * @inode:		inode
6638  * @bh:			optional buffer of the block to be freed
6639  * @block:		starting physical block to be freed
6640  * @count:		number of blocks to be freed
6641  * @flags:		flags used by ext4_free_blocks
6642  */
ext4_free_blocks(handle_t * handle,struct inode * inode,struct buffer_head * bh,ext4_fsblk_t block,unsigned long count,int flags)6643 void ext4_free_blocks(handle_t *handle, struct inode *inode,
6644 		      struct buffer_head *bh, ext4_fsblk_t block,
6645 		      unsigned long count, int flags)
6646 {
6647 	struct super_block *sb = inode->i_sb;
6648 	unsigned int overflow;
6649 	struct ext4_sb_info *sbi;
6650 
6651 	sbi = EXT4_SB(sb);
6652 
6653 	if (bh) {
6654 		if (block)
6655 			BUG_ON(block != bh->b_blocknr);
6656 		else
6657 			block = bh->b_blocknr;
6658 	}
6659 
6660 	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
6661 		ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count));
6662 		return;
6663 	}
6664 
6665 	might_sleep();
6666 
6667 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
6668 	    !ext4_inode_block_valid(inode, block, count)) {
6669 		ext4_error(sb, "Freeing blocks not in datazone - "
6670 			   "block = %llu, count = %lu", block, count);
6671 		return;
6672 	}
6673 	flags |= EXT4_FREE_BLOCKS_VALIDATED;
6674 
6675 	ext4_debug("freeing block %llu\n", block);
6676 	trace_ext4_free_blocks(inode, block, count, flags);
6677 
6678 	if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
6679 		BUG_ON(count > 1);
6680 
6681 		ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
6682 			    inode, bh, block);
6683 	}
6684 
6685 	/*
6686 	 * If the extent to be freed does not begin on a cluster
6687 	 * boundary, we need to deal with partial clusters at the
6688 	 * beginning and end of the extent.  Normally we will free
6689 	 * blocks at the beginning or the end unless we are explicitly
6690 	 * requested to avoid doing so.
6691 	 */
6692 	overflow = EXT4_PBLK_COFF(sbi, block);
6693 	if (overflow) {
6694 		if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
6695 			overflow = sbi->s_cluster_ratio - overflow;
6696 			block += overflow;
6697 			if (count > overflow)
6698 				count -= overflow;
6699 			else
6700 				return;
6701 		} else {
6702 			block -= overflow;
6703 			count += overflow;
6704 		}
6705 		/* The range changed so it's no longer validated */
6706 		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
6707 	}
6708 	overflow = EXT4_LBLK_COFF(sbi, count);
6709 	if (overflow) {
6710 		if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
6711 			if (count > overflow)
6712 				count -= overflow;
6713 			else
6714 				return;
6715 		} else
6716 			count += sbi->s_cluster_ratio - overflow;
6717 		/* The range changed so it's no longer validated */
6718 		flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
6719 	}
6720 
6721 	if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
6722 		int i;
6723 		int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
6724 
6725 		for (i = 0; i < count; i++) {
6726 			cond_resched();
6727 			if (is_metadata)
6728 				bh = sb_find_get_block(inode->i_sb, block + i);
6729 			ext4_forget(handle, is_metadata, inode, bh, block + i);
6730 		}
6731 	}
6732 
6733 	ext4_mb_clear_bb(handle, inode, block, count, flags);
6734 }
6735 
6736 /**
6737  * ext4_group_add_blocks() -- Add given blocks to an existing group
6738  * @handle:			handle to this transaction
6739  * @sb:				super block
6740  * @block:			start physical block to add to the block group
6741  * @count:			number of blocks to free
6742  *
6743  * This marks the blocks as free in the bitmap and buddy.
6744  */
ext4_group_add_blocks(handle_t * handle,struct super_block * sb,ext4_fsblk_t block,unsigned long count)6745 int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
6746 			 ext4_fsblk_t block, unsigned long count)
6747 {
6748 	struct buffer_head *bitmap_bh = NULL;
6749 	struct buffer_head *gd_bh;
6750 	ext4_group_t block_group;
6751 	ext4_grpblk_t bit;
6752 	unsigned int i;
6753 	struct ext4_group_desc *desc;
6754 	struct ext4_sb_info *sbi = EXT4_SB(sb);
6755 	struct ext4_buddy e4b;
6756 	int err = 0, ret, free_clusters_count;
6757 	ext4_grpblk_t clusters_freed;
6758 	ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
6759 	ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
6760 	unsigned long cluster_count = last_cluster - first_cluster + 1;
6761 
6762 	ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
6763 
6764 	if (count == 0)
6765 		return 0;
6766 
6767 	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
6768 	/*
6769 	 * Check to see if we are freeing blocks across a group
6770 	 * boundary.
6771 	 */
6772 	if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) {
6773 		ext4_warning(sb, "too many blocks added to group %u",
6774 			     block_group);
6775 		err = -EINVAL;
6776 		goto error_return;
6777 	}
6778 
6779 	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
6780 	if (IS_ERR(bitmap_bh)) {
6781 		err = PTR_ERR(bitmap_bh);
6782 		bitmap_bh = NULL;
6783 		goto error_return;
6784 	}
6785 
6786 	desc = ext4_get_group_desc(sb, block_group, &gd_bh);
6787 	if (!desc) {
6788 		err = -EIO;
6789 		goto error_return;
6790 	}
6791 
6792 	if (!ext4_sb_block_valid(sb, NULL, block, count)) {
6793 		ext4_error(sb, "Adding blocks in system zones - "
6794 			   "Block = %llu, count = %lu",
6795 			   block, count);
6796 		err = -EINVAL;
6797 		goto error_return;
6798 	}
6799 
6800 	BUFFER_TRACE(bitmap_bh, "getting write access");
6801 	err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
6802 					    EXT4_JTR_NONE);
6803 	if (err)
6804 		goto error_return;
6805 
6806 	/*
6807 	 * We are about to modify some metadata.  Call the journal APIs
6808 	 * to unshare ->b_data if a currently-committing transaction is
6809 	 * using it
6810 	 */
6811 	BUFFER_TRACE(gd_bh, "get_write_access");
6812 	err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
6813 	if (err)
6814 		goto error_return;
6815 
6816 	for (i = 0, clusters_freed = 0; i < cluster_count; i++) {
6817 		BUFFER_TRACE(bitmap_bh, "clear bit");
6818 		if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
6819 			ext4_error(sb, "bit already cleared for block %llu",
6820 				   (ext4_fsblk_t)(block + i));
6821 			BUFFER_TRACE(bitmap_bh, "bit already cleared");
6822 		} else {
6823 			clusters_freed++;
6824 		}
6825 	}
6826 
6827 	err = ext4_mb_load_buddy(sb, block_group, &e4b);
6828 	if (err)
6829 		goto error_return;
6830 
6831 	/*
6832 	 * need to update group_info->bb_free and bitmap
6833 	 * with group lock held. generate_buddy look at
6834 	 * them with group lock_held
6835 	 */
6836 	ext4_lock_group(sb, block_group);
6837 	mb_clear_bits(bitmap_bh->b_data, bit, cluster_count);
6838 	mb_free_blocks(NULL, &e4b, bit, cluster_count);
6839 	free_clusters_count = clusters_freed +
6840 		ext4_free_group_clusters(sb, desc);
6841 	ext4_free_group_clusters_set(sb, desc, free_clusters_count);
6842 	ext4_block_bitmap_csum_set(sb, desc, bitmap_bh);
6843 	ext4_group_desc_csum_set(sb, block_group, desc);
6844 	ext4_unlock_group(sb, block_group);
6845 	percpu_counter_add(&sbi->s_freeclusters_counter,
6846 			   clusters_freed);
6847 
6848 	if (sbi->s_log_groups_per_flex) {
6849 		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
6850 		atomic64_add(clusters_freed,
6851 			     &sbi_array_rcu_deref(sbi, s_flex_groups,
6852 						  flex_group)->free_clusters);
6853 	}
6854 
6855 	ext4_mb_unload_buddy(&e4b);
6856 
6857 	/* We dirtied the bitmap block */
6858 	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
6859 	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
6860 
6861 	/* And the group descriptor block */
6862 	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
6863 	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
6864 	if (!err)
6865 		err = ret;
6866 
6867 error_return:
6868 	brelse(bitmap_bh);
6869 	ext4_std_error(sb, err);
6870 	return err;
6871 }
6872 
6873 /**
6874  * ext4_trim_extent -- function to TRIM one single free extent in the group
6875  * @sb:		super block for the file system
6876  * @start:	starting block of the free extent in the alloc. group
6877  * @count:	number of blocks to TRIM
6878  * @e4b:	ext4 buddy for the group
6879  *
6880  * Trim "count" blocks starting at "start" in the "group". To assure that no
6881  * one will allocate those blocks, mark it as used in buddy bitmap. This must
6882  * be called with under the group lock.
6883  */
ext4_trim_extent(struct super_block * sb,int start,int count,struct ext4_buddy * e4b)6884 static int ext4_trim_extent(struct super_block *sb,
6885 		int start, int count, struct ext4_buddy *e4b)
6886 __releases(bitlock)
6887 __acquires(bitlock)
6888 {
6889 	struct ext4_free_extent ex;
6890 	ext4_group_t group = e4b->bd_group;
6891 	int ret = 0;
6892 
6893 	trace_ext4_trim_extent(sb, group, start, count);
6894 
6895 	assert_spin_locked(ext4_group_lock_ptr(sb, group));
6896 
6897 	ex.fe_start = start;
6898 	ex.fe_group = group;
6899 	ex.fe_len = count;
6900 
6901 	/*
6902 	 * Mark blocks used, so no one can reuse them while
6903 	 * being trimmed.
6904 	 */
6905 	mb_mark_used(e4b, &ex);
6906 	ext4_unlock_group(sb, group);
6907 	ret = ext4_issue_discard(sb, group, start, count, NULL);
6908 	ext4_lock_group(sb, group);
6909 	mb_free_blocks(NULL, e4b, start, ex.fe_len);
6910 	return ret;
6911 }
6912 
ext4_last_grp_cluster(struct super_block * sb,ext4_group_t grp)6913 static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb,
6914 					   ext4_group_t grp)
6915 {
6916 	unsigned long nr_clusters_in_group;
6917 
6918 	if (grp < (ext4_get_groups_count(sb) - 1))
6919 		nr_clusters_in_group = EXT4_CLUSTERS_PER_GROUP(sb);
6920 	else
6921 		nr_clusters_in_group = (ext4_blocks_count(EXT4_SB(sb)->s_es) -
6922 					ext4_group_first_block_no(sb, grp))
6923 				       >> EXT4_CLUSTER_BITS(sb);
6924 
6925 	return nr_clusters_in_group - 1;
6926 }
6927 
ext4_trim_interrupted(void)6928 static bool ext4_trim_interrupted(void)
6929 {
6930 	return fatal_signal_pending(current) || freezing(current);
6931 }
6932 
ext4_try_to_trim_range(struct super_block * sb,struct ext4_buddy * e4b,ext4_grpblk_t start,ext4_grpblk_t max,ext4_grpblk_t minblocks)6933 static int ext4_try_to_trim_range(struct super_block *sb,
6934 		struct ext4_buddy *e4b, ext4_grpblk_t start,
6935 		ext4_grpblk_t max, ext4_grpblk_t minblocks)
6936 __acquires(ext4_group_lock_ptr(sb, e4b->bd_group))
6937 __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
6938 {
6939 	ext4_grpblk_t next, count, free_count, last, origin_start;
6940 	bool set_trimmed = false;
6941 	void *bitmap;
6942 
6943 	last = ext4_last_grp_cluster(sb, e4b->bd_group);
6944 	bitmap = e4b->bd_bitmap;
6945 	if (start == 0 && max >= last)
6946 		set_trimmed = true;
6947 	origin_start = start;
6948 	start = max(e4b->bd_info->bb_first_free, start);
6949 	count = 0;
6950 	free_count = 0;
6951 
6952 	while (start <= max) {
6953 		start = mb_find_next_zero_bit(bitmap, max + 1, start);
6954 		if (start > max)
6955 			break;
6956 
6957 		next = mb_find_next_bit(bitmap, last + 1, start);
6958 		if (origin_start == 0 && next >= last)
6959 			set_trimmed = true;
6960 
6961 		if ((next - start) >= minblocks) {
6962 			int ret = ext4_trim_extent(sb, start, next - start, e4b);
6963 
6964 			if (ret && ret != -EOPNOTSUPP)
6965 				return count;
6966 			count += next - start;
6967 		}
6968 		free_count += next - start;
6969 		start = next + 1;
6970 
6971 		if (ext4_trim_interrupted())
6972 			return count;
6973 
6974 		if (need_resched()) {
6975 			ext4_unlock_group(sb, e4b->bd_group);
6976 			cond_resched();
6977 			ext4_lock_group(sb, e4b->bd_group);
6978 		}
6979 
6980 		if ((e4b->bd_info->bb_free - free_count) < minblocks)
6981 			break;
6982 	}
6983 
6984 	if (set_trimmed)
6985 		EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info);
6986 
6987 	return count;
6988 }
6989 
6990 /**
6991  * ext4_trim_all_free -- function to trim all free space in alloc. group
6992  * @sb:			super block for file system
6993  * @group:		group to be trimmed
6994  * @start:		first group block to examine
6995  * @max:		last group block to examine
6996  * @minblocks:		minimum extent block count
6997  *
6998  * ext4_trim_all_free walks through group's block bitmap searching for free
6999  * extents. When the free extent is found, mark it as used in group buddy
7000  * bitmap. Then issue a TRIM command on this extent and free the extent in
7001  * the group buddy bitmap.
7002  */
7003 static ext4_grpblk_t
ext4_trim_all_free(struct super_block * sb,ext4_group_t group,ext4_grpblk_t start,ext4_grpblk_t max,ext4_grpblk_t minblocks)7004 ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
7005 		   ext4_grpblk_t start, ext4_grpblk_t max,
7006 		   ext4_grpblk_t minblocks)
7007 {
7008 	struct ext4_buddy e4b;
7009 	int ret;
7010 
7011 	trace_ext4_trim_all_free(sb, group, start, max);
7012 
7013 	ret = ext4_mb_load_buddy(sb, group, &e4b);
7014 	if (ret) {
7015 		ext4_warning(sb, "Error %d loading buddy information for %u",
7016 			     ret, group);
7017 		return ret;
7018 	}
7019 
7020 	ext4_lock_group(sb, group);
7021 
7022 	if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
7023 	    minblocks < EXT4_SB(sb)->s_last_trim_minblks)
7024 		ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
7025 	else
7026 		ret = 0;
7027 
7028 	ext4_unlock_group(sb, group);
7029 	ext4_mb_unload_buddy(&e4b);
7030 
7031 	ext4_debug("trimmed %d blocks in the group %d\n",
7032 		ret, group);
7033 
7034 	return ret;
7035 }
7036 
7037 /**
7038  * ext4_trim_fs() -- trim ioctl handle function
7039  * @sb:			superblock for filesystem
7040  * @range:		fstrim_range structure
7041  *
7042  * start:	First Byte to trim
7043  * len:		number of Bytes to trim from start
7044  * minlen:	minimum extent length in Bytes
7045  * ext4_trim_fs goes through all allocation groups containing Bytes from
7046  * start to start+len. For each such a group ext4_trim_all_free function
7047  * is invoked to trim all free space.
7048  */
ext4_trim_fs(struct super_block * sb,struct fstrim_range * range)7049 int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
7050 {
7051 	unsigned int discard_granularity = bdev_discard_granularity(sb->s_bdev);
7052 	struct ext4_group_info *grp;
7053 	ext4_group_t group, first_group, last_group;
7054 	ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
7055 	uint64_t start, end, minlen, trimmed = 0;
7056 	ext4_fsblk_t first_data_blk =
7057 			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
7058 	ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
7059 	int ret = 0;
7060 
7061 	start = range->start >> sb->s_blocksize_bits;
7062 	end = start + (range->len >> sb->s_blocksize_bits) - 1;
7063 	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
7064 			      range->minlen >> sb->s_blocksize_bits);
7065 
7066 	if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
7067 	    start >= max_blks ||
7068 	    range->len < sb->s_blocksize)
7069 		return -EINVAL;
7070 	/* No point to try to trim less than discard granularity */
7071 	if (range->minlen < discard_granularity) {
7072 		minlen = EXT4_NUM_B2C(EXT4_SB(sb),
7073 				discard_granularity >> sb->s_blocksize_bits);
7074 		if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
7075 			goto out;
7076 	}
7077 	if (end >= max_blks - 1)
7078 		end = max_blks - 1;
7079 	if (end <= first_data_blk)
7080 		goto out;
7081 	if (start < first_data_blk)
7082 		start = first_data_blk;
7083 
7084 	/* Determine first and last group to examine based on start and end */
7085 	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
7086 				     &first_group, &first_cluster);
7087 	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
7088 				     &last_group, &last_cluster);
7089 
7090 	/* end now represents the last cluster to discard in this group */
7091 	end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
7092 
7093 	for (group = first_group; group <= last_group; group++) {
7094 		if (ext4_trim_interrupted())
7095 			break;
7096 		grp = ext4_get_group_info(sb, group);
7097 		if (!grp)
7098 			continue;
7099 		/* We only do this if the grp has never been initialized */
7100 		if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
7101 			ret = ext4_mb_init_group(sb, group, GFP_NOFS);
7102 			if (ret)
7103 				break;
7104 		}
7105 
7106 		/*
7107 		 * For all the groups except the last one, last cluster will
7108 		 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
7109 		 * change it for the last group, note that last_cluster is
7110 		 * already computed earlier by ext4_get_group_no_and_offset()
7111 		 */
7112 		if (group == last_group)
7113 			end = last_cluster;
7114 		if (grp->bb_free >= minlen) {
7115 			cnt = ext4_trim_all_free(sb, group, first_cluster,
7116 						 end, minlen);
7117 			if (cnt < 0) {
7118 				ret = cnt;
7119 				break;
7120 			}
7121 			trimmed += cnt;
7122 		}
7123 
7124 		/*
7125 		 * For every group except the first one, we are sure
7126 		 * that the first cluster to discard will be cluster #0.
7127 		 */
7128 		first_cluster = 0;
7129 	}
7130 
7131 	if (!ret)
7132 		EXT4_SB(sb)->s_last_trim_minblks = minlen;
7133 
7134 out:
7135 	range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
7136 	return ret;
7137 }
7138 
7139 /* Iterate all the free extents in the group. */
7140 int
ext4_mballoc_query_range(struct super_block * sb,ext4_group_t group,ext4_grpblk_t start,ext4_grpblk_t end,ext4_mballoc_query_range_fn formatter,void * priv)7141 ext4_mballoc_query_range(
7142 	struct super_block		*sb,
7143 	ext4_group_t			group,
7144 	ext4_grpblk_t			start,
7145 	ext4_grpblk_t			end,
7146 	ext4_mballoc_query_range_fn	formatter,
7147 	void				*priv)
7148 {
7149 	void				*bitmap;
7150 	ext4_grpblk_t			next;
7151 	struct ext4_buddy		e4b;
7152 	int				error;
7153 
7154 	error = ext4_mb_load_buddy(sb, group, &e4b);
7155 	if (error)
7156 		return error;
7157 	bitmap = e4b.bd_bitmap;
7158 
7159 	ext4_lock_group(sb, group);
7160 
7161 	start = max(e4b.bd_info->bb_first_free, start);
7162 	if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
7163 		end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
7164 
7165 	while (start <= end) {
7166 		start = mb_find_next_zero_bit(bitmap, end + 1, start);
7167 		if (start > end)
7168 			break;
7169 		next = mb_find_next_bit(bitmap, end + 1, start);
7170 
7171 		ext4_unlock_group(sb, group);
7172 		error = formatter(sb, group, start, next - start, priv);
7173 		if (error)
7174 			goto out_unload;
7175 		ext4_lock_group(sb, group);
7176 
7177 		start = next + 1;
7178 	}
7179 
7180 	ext4_unlock_group(sb, group);
7181 out_unload:
7182 	ext4_mb_unload_buddy(&e4b);
7183 
7184 	return error;
7185 }
7186