1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext2/inode.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 *
10 * from
11 *
12 * linux/fs/minix/inode.c
13 *
14 * Copyright (C) 1991, 1992 Linus Torvalds
15 *
16 * Goal-directed block allocation by Stephen Tweedie
17 * (sct@dcs.ed.ac.uk), 1993, 1998
18 * Big-endian to little-endian byte-swapping/bitmaps by
19 * David S. Miller (davem@caip.rutgers.edu), 1995
20 * 64-bit file support on 64-bit platforms by Jakub Jelinek
21 * (jj@sunsite.ms.mff.cuni.cz)
22 *
23 * Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
24 */
25
26 #include <linux/time.h>
27 #include <linux/highuid.h>
28 #include <linux/pagemap.h>
29 #include <linux/dax.h>
30 #include <linux/blkdev.h>
31 #include <linux/quotaops.h>
32 #include <linux/writeback.h>
33 #include <linux/buffer_head.h>
34 #include <linux/mpage.h>
35 #include <linux/fiemap.h>
36 #include <linux/iomap.h>
37 #include <linux/namei.h>
38 #include <linux/uio.h>
39 #include "ext2.h"
40 #include "acl.h"
41 #include "xattr.h"
42
43 static int __ext2_write_inode(struct inode *inode, int do_sync);
44
45 /*
46 * Test whether an inode is a fast symlink.
47 */
ext2_inode_is_fast_symlink(struct inode * inode)48 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
49 {
50 int ea_blocks = EXT2_I(inode)->i_file_acl ?
51 (inode->i_sb->s_blocksize >> 9) : 0;
52
53 return (S_ISLNK(inode->i_mode) &&
54 inode->i_blocks - ea_blocks == 0);
55 }
56
57 static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
58
ext2_write_failed(struct address_space * mapping,loff_t to)59 static void ext2_write_failed(struct address_space *mapping, loff_t to)
60 {
61 struct inode *inode = mapping->host;
62
63 if (to > inode->i_size) {
64 truncate_pagecache(inode, inode->i_size);
65 ext2_truncate_blocks(inode, inode->i_size);
66 }
67 }
68
69 /*
70 * Called at the last iput() if i_nlink is zero.
71 */
ext2_evict_inode(struct inode * inode)72 void ext2_evict_inode(struct inode * inode)
73 {
74 struct ext2_block_alloc_info *rsv;
75 int want_delete = 0;
76
77 if (!inode->i_nlink && !is_bad_inode(inode)) {
78 want_delete = 1;
79 dquot_initialize(inode);
80 } else {
81 dquot_drop(inode);
82 }
83
84 truncate_inode_pages_final(&inode->i_data);
85
86 if (want_delete) {
87 sb_start_intwrite(inode->i_sb);
88 /* set dtime */
89 EXT2_I(inode)->i_dtime = ktime_get_real_seconds();
90 mark_inode_dirty(inode);
91 __ext2_write_inode(inode, inode_needs_sync(inode));
92 /* truncate to 0 */
93 inode->i_size = 0;
94 if (inode->i_blocks)
95 ext2_truncate_blocks(inode, 0);
96 ext2_xattr_delete_inode(inode);
97 }
98
99 invalidate_inode_buffers(inode);
100 clear_inode(inode);
101
102 ext2_discard_reservation(inode);
103 rsv = EXT2_I(inode)->i_block_alloc_info;
104 EXT2_I(inode)->i_block_alloc_info = NULL;
105 if (unlikely(rsv))
106 kfree(rsv);
107
108 if (want_delete) {
109 ext2_free_inode(inode);
110 sb_end_intwrite(inode->i_sb);
111 }
112 }
113
114 typedef struct {
115 __le32 *p;
116 __le32 key;
117 struct buffer_head *bh;
118 } Indirect;
119
add_chain(Indirect * p,struct buffer_head * bh,__le32 * v)120 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
121 {
122 p->key = *(p->p = v);
123 p->bh = bh;
124 }
125
verify_chain(Indirect * from,Indirect * to)126 static inline int verify_chain(Indirect *from, Indirect *to)
127 {
128 while (from <= to && from->key == *from->p)
129 from++;
130 return (from > to);
131 }
132
133 /**
134 * ext2_block_to_path - parse the block number into array of offsets
135 * @inode: inode in question (we are only interested in its superblock)
136 * @i_block: block number to be parsed
137 * @offsets: array to store the offsets in
138 * @boundary: set this non-zero if the referred-to block is likely to be
139 * followed (on disk) by an indirect block.
140 * To store the locations of file's data ext2 uses a data structure common
141 * for UNIX filesystems - tree of pointers anchored in the inode, with
142 * data blocks at leaves and indirect blocks in intermediate nodes.
143 * This function translates the block number into path in that tree -
144 * return value is the path length and @offsets[n] is the offset of
145 * pointer to (n+1)th node in the nth one. If @block is out of range
146 * (negative or too large) warning is printed and zero returned.
147 *
148 * Note: function doesn't find node addresses, so no IO is needed. All
149 * we need to know is the capacity of indirect blocks (taken from the
150 * inode->i_sb).
151 */
152
153 /*
154 * Portability note: the last comparison (check that we fit into triple
155 * indirect block) is spelled differently, because otherwise on an
156 * architecture with 32-bit longs and 8Kb pages we might get into trouble
157 * if our filesystem had 8Kb blocks. We might use long long, but that would
158 * kill us on x86. Oh, well, at least the sign propagation does not matter -
159 * i_block would have to be negative in the very beginning, so we would not
160 * get there at all.
161 */
162
ext2_block_to_path(struct inode * inode,long i_block,int offsets[4],int * boundary)163 static int ext2_block_to_path(struct inode *inode,
164 long i_block, int offsets[4], int *boundary)
165 {
166 int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
167 int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
168 const long direct_blocks = EXT2_NDIR_BLOCKS,
169 indirect_blocks = ptrs,
170 double_blocks = (1 << (ptrs_bits * 2));
171 int n = 0;
172 int final = 0;
173
174 if (i_block < 0) {
175 ext2_msg(inode->i_sb, KERN_WARNING,
176 "warning: %s: block < 0", __func__);
177 } else if (i_block < direct_blocks) {
178 offsets[n++] = i_block;
179 final = direct_blocks;
180 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
181 offsets[n++] = EXT2_IND_BLOCK;
182 offsets[n++] = i_block;
183 final = ptrs;
184 } else if ((i_block -= indirect_blocks) < double_blocks) {
185 offsets[n++] = EXT2_DIND_BLOCK;
186 offsets[n++] = i_block >> ptrs_bits;
187 offsets[n++] = i_block & (ptrs - 1);
188 final = ptrs;
189 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
190 offsets[n++] = EXT2_TIND_BLOCK;
191 offsets[n++] = i_block >> (ptrs_bits * 2);
192 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
193 offsets[n++] = i_block & (ptrs - 1);
194 final = ptrs;
195 } else {
196 ext2_msg(inode->i_sb, KERN_WARNING,
197 "warning: %s: block is too big", __func__);
198 }
199 if (boundary)
200 *boundary = final - 1 - (i_block & (ptrs - 1));
201
202 return n;
203 }
204
205 /**
206 * ext2_get_branch - read the chain of indirect blocks leading to data
207 * @inode: inode in question
208 * @depth: depth of the chain (1 - direct pointer, etc.)
209 * @offsets: offsets of pointers in inode/indirect blocks
210 * @chain: place to store the result
211 * @err: here we store the error value
212 *
213 * Function fills the array of triples <key, p, bh> and returns %NULL
214 * if everything went OK or the pointer to the last filled triple
215 * (incomplete one) otherwise. Upon the return chain[i].key contains
216 * the number of (i+1)-th block in the chain (as it is stored in memory,
217 * i.e. little-endian 32-bit), chain[i].p contains the address of that
218 * number (it points into struct inode for i==0 and into the bh->b_data
219 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
220 * block for i>0 and NULL for i==0. In other words, it holds the block
221 * numbers of the chain, addresses they were taken from (and where we can
222 * verify that chain did not change) and buffer_heads hosting these
223 * numbers.
224 *
225 * Function stops when it stumbles upon zero pointer (absent block)
226 * (pointer to last triple returned, *@err == 0)
227 * or when it gets an IO error reading an indirect block
228 * (ditto, *@err == -EIO)
229 * or when it notices that chain had been changed while it was reading
230 * (ditto, *@err == -EAGAIN)
231 * or when it reads all @depth-1 indirect blocks successfully and finds
232 * the whole chain, all way to the data (returns %NULL, *err == 0).
233 */
ext2_get_branch(struct inode * inode,int depth,int * offsets,Indirect chain[4],int * err)234 static Indirect *ext2_get_branch(struct inode *inode,
235 int depth,
236 int *offsets,
237 Indirect chain[4],
238 int *err)
239 {
240 struct super_block *sb = inode->i_sb;
241 Indirect *p = chain;
242 struct buffer_head *bh;
243
244 *err = 0;
245 /* i_data is not going away, no lock needed */
246 add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
247 if (!p->key)
248 goto no_block;
249 while (--depth) {
250 bh = sb_bread(sb, le32_to_cpu(p->key));
251 if (!bh)
252 goto failure;
253 read_lock(&EXT2_I(inode)->i_meta_lock);
254 if (!verify_chain(chain, p))
255 goto changed;
256 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
257 read_unlock(&EXT2_I(inode)->i_meta_lock);
258 if (!p->key)
259 goto no_block;
260 }
261 return NULL;
262
263 changed:
264 read_unlock(&EXT2_I(inode)->i_meta_lock);
265 brelse(bh);
266 *err = -EAGAIN;
267 goto no_block;
268 failure:
269 *err = -EIO;
270 no_block:
271 return p;
272 }
273
274 /**
275 * ext2_find_near - find a place for allocation with sufficient locality
276 * @inode: owner
277 * @ind: descriptor of indirect block.
278 *
279 * This function returns the preferred place for block allocation.
280 * It is used when heuristic for sequential allocation fails.
281 * Rules are:
282 * + if there is a block to the left of our position - allocate near it.
283 * + if pointer will live in indirect block - allocate near that block.
284 * + if pointer will live in inode - allocate in the same cylinder group.
285 *
286 * In the latter case we colour the starting block by the callers PID to
287 * prevent it from clashing with concurrent allocations for a different inode
288 * in the same block group. The PID is used here so that functionally related
289 * files will be close-by on-disk.
290 *
291 * Caller must make sure that @ind is valid and will stay that way.
292 */
293
ext2_find_near(struct inode * inode,Indirect * ind)294 static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
295 {
296 struct ext2_inode_info *ei = EXT2_I(inode);
297 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
298 __le32 *p;
299 ext2_fsblk_t bg_start;
300 ext2_fsblk_t colour;
301
302 /* Try to find previous block */
303 for (p = ind->p - 1; p >= start; p--)
304 if (*p)
305 return le32_to_cpu(*p);
306
307 /* No such thing, so let's try location of indirect block */
308 if (ind->bh)
309 return ind->bh->b_blocknr;
310
311 /*
312 * It is going to be referred from inode itself? OK, just put it into
313 * the same cylinder group then.
314 */
315 bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
316 colour = (current->pid % 16) *
317 (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
318 return bg_start + colour;
319 }
320
321 /**
322 * ext2_find_goal - find a preferred place for allocation.
323 * @inode: owner
324 * @block: block we want
325 * @partial: pointer to the last triple within a chain
326 *
327 * Returns preferred place for a block (the goal).
328 */
329
ext2_find_goal(struct inode * inode,long block,Indirect * partial)330 static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
331 Indirect *partial)
332 {
333 struct ext2_block_alloc_info *block_i;
334
335 block_i = EXT2_I(inode)->i_block_alloc_info;
336
337 /*
338 * try the heuristic for sequential allocation,
339 * failing that at least try to get decent locality.
340 */
341 if (block_i && (block == block_i->last_alloc_logical_block + 1)
342 && (block_i->last_alloc_physical_block != 0)) {
343 return block_i->last_alloc_physical_block + 1;
344 }
345
346 return ext2_find_near(inode, partial);
347 }
348
349 /**
350 * ext2_blks_to_allocate: Look up the block map and count the number
351 * of direct blocks need to be allocated for the given branch.
352 *
353 * @branch: chain of indirect blocks
354 * @k: number of blocks need for indirect blocks
355 * @blks: number of data blocks to be mapped.
356 * @blocks_to_boundary: the offset in the indirect block
357 *
358 * return the number of direct blocks to allocate.
359 */
360 static int
ext2_blks_to_allocate(Indirect * branch,int k,unsigned long blks,int blocks_to_boundary)361 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
362 int blocks_to_boundary)
363 {
364 unsigned long count = 0;
365
366 /*
367 * Simple case, [t,d]Indirect block(s) has not allocated yet
368 * then it's clear blocks on that path have not allocated
369 */
370 if (k > 0) {
371 /* right now don't hanel cross boundary allocation */
372 if (blks < blocks_to_boundary + 1)
373 count += blks;
374 else
375 count += blocks_to_boundary + 1;
376 return count;
377 }
378
379 count++;
380 while (count < blks && count <= blocks_to_boundary
381 && le32_to_cpu(*(branch[0].p + count)) == 0) {
382 count++;
383 }
384 return count;
385 }
386
387 /**
388 * ext2_alloc_blocks: multiple allocate blocks needed for a branch
389 * @indirect_blks: the number of blocks need to allocate for indirect
390 * blocks
391 * @blks: the number of blocks need to allocate for direct blocks
392 * @new_blocks: on return it will store the new block numbers for
393 * the indirect blocks(if needed) and the first direct block,
394 */
ext2_alloc_blocks(struct inode * inode,ext2_fsblk_t goal,int indirect_blks,int blks,ext2_fsblk_t new_blocks[4],int * err)395 static int ext2_alloc_blocks(struct inode *inode,
396 ext2_fsblk_t goal, int indirect_blks, int blks,
397 ext2_fsblk_t new_blocks[4], int *err)
398 {
399 int target, i;
400 unsigned long count = 0;
401 int index = 0;
402 ext2_fsblk_t current_block = 0;
403 int ret = 0;
404
405 /*
406 * Here we try to allocate the requested multiple blocks at once,
407 * on a best-effort basis.
408 * To build a branch, we should allocate blocks for
409 * the indirect blocks(if not allocated yet), and at least
410 * the first direct block of this branch. That's the
411 * minimum number of blocks need to allocate(required)
412 */
413 target = blks + indirect_blks;
414
415 while (1) {
416 count = target;
417 /* allocating blocks for indirect blocks and direct blocks */
418 current_block = ext2_new_blocks(inode,goal,&count,err);
419 if (*err)
420 goto failed_out;
421
422 target -= count;
423 /* allocate blocks for indirect blocks */
424 while (index < indirect_blks && count) {
425 new_blocks[index++] = current_block++;
426 count--;
427 }
428
429 if (count > 0)
430 break;
431 }
432
433 /* save the new block number for the first direct block */
434 new_blocks[index] = current_block;
435
436 /* total number of blocks allocated for direct blocks */
437 ret = count;
438 *err = 0;
439 return ret;
440 failed_out:
441 for (i = 0; i <index; i++)
442 ext2_free_blocks(inode, new_blocks[i], 1);
443 if (index)
444 mark_inode_dirty(inode);
445 return ret;
446 }
447
448 /**
449 * ext2_alloc_branch - allocate and set up a chain of blocks.
450 * @inode: owner
451 * @indirect_blks: depth of the chain (number of blocks to allocate)
452 * @blks: number of allocated direct blocks
453 * @goal: preferred place for allocation
454 * @offsets: offsets (in the blocks) to store the pointers to next.
455 * @branch: place to store the chain in.
456 *
457 * This function allocates @num blocks, zeroes out all but the last one,
458 * links them into chain and (if we are synchronous) writes them to disk.
459 * In other words, it prepares a branch that can be spliced onto the
460 * inode. It stores the information about that chain in the branch[], in
461 * the same format as ext2_get_branch() would do. We are calling it after
462 * we had read the existing part of chain and partial points to the last
463 * triple of that (one with zero ->key). Upon the exit we have the same
464 * picture as after the successful ext2_get_block(), except that in one
465 * place chain is disconnected - *branch->p is still zero (we did not
466 * set the last link), but branch->key contains the number that should
467 * be placed into *branch->p to fill that gap.
468 *
469 * If allocation fails we free all blocks we've allocated (and forget
470 * their buffer_heads) and return the error value the from failed
471 * ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
472 * as described above and return 0.
473 */
474
ext2_alloc_branch(struct inode * inode,int indirect_blks,int * blks,ext2_fsblk_t goal,int * offsets,Indirect * branch)475 static int ext2_alloc_branch(struct inode *inode,
476 int indirect_blks, int *blks, ext2_fsblk_t goal,
477 int *offsets, Indirect *branch)
478 {
479 int blocksize = inode->i_sb->s_blocksize;
480 int i, n = 0;
481 int err = 0;
482 struct buffer_head *bh;
483 int num;
484 ext2_fsblk_t new_blocks[4];
485 ext2_fsblk_t current_block;
486
487 num = ext2_alloc_blocks(inode, goal, indirect_blks,
488 *blks, new_blocks, &err);
489 if (err)
490 return err;
491
492 branch[0].key = cpu_to_le32(new_blocks[0]);
493 /*
494 * metadata blocks and data blocks are allocated.
495 */
496 for (n = 1; n <= indirect_blks; n++) {
497 /*
498 * Get buffer_head for parent block, zero it out
499 * and set the pointer to new one, then send
500 * parent to disk.
501 */
502 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
503 if (unlikely(!bh)) {
504 err = -ENOMEM;
505 goto failed;
506 }
507 branch[n].bh = bh;
508 lock_buffer(bh);
509 memset(bh->b_data, 0, blocksize);
510 branch[n].p = (__le32 *) bh->b_data + offsets[n];
511 branch[n].key = cpu_to_le32(new_blocks[n]);
512 *branch[n].p = branch[n].key;
513 if ( n == indirect_blks) {
514 current_block = new_blocks[n];
515 /*
516 * End of chain, update the last new metablock of
517 * the chain to point to the new allocated
518 * data blocks numbers
519 */
520 for (i=1; i < num; i++)
521 *(branch[n].p + i) = cpu_to_le32(++current_block);
522 }
523 set_buffer_uptodate(bh);
524 unlock_buffer(bh);
525 mark_buffer_dirty_inode(bh, inode);
526 /* We used to sync bh here if IS_SYNC(inode).
527 * But we now rely upon generic_write_sync()
528 * and b_inode_buffers. But not for directories.
529 */
530 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
531 sync_dirty_buffer(bh);
532 }
533 *blks = num;
534 return err;
535
536 failed:
537 for (i = 1; i < n; i++)
538 bforget(branch[i].bh);
539 for (i = 0; i < indirect_blks; i++)
540 ext2_free_blocks(inode, new_blocks[i], 1);
541 ext2_free_blocks(inode, new_blocks[i], num);
542 return err;
543 }
544
545 /**
546 * ext2_splice_branch - splice the allocated branch onto inode.
547 * @inode: owner
548 * @block: (logical) number of block we are adding
549 * @where: location of missing link
550 * @num: number of indirect blocks we are adding
551 * @blks: number of direct blocks we are adding
552 *
553 * This function fills the missing link and does all housekeeping needed in
554 * inode (->i_blocks, etc.). In case of success we end up with the full
555 * chain to new block and return 0.
556 */
ext2_splice_branch(struct inode * inode,long block,Indirect * where,int num,int blks)557 static void ext2_splice_branch(struct inode *inode,
558 long block, Indirect *where, int num, int blks)
559 {
560 int i;
561 struct ext2_block_alloc_info *block_i;
562 ext2_fsblk_t current_block;
563
564 block_i = EXT2_I(inode)->i_block_alloc_info;
565
566 /* XXX LOCKING probably should have i_meta_lock ?*/
567 /* That's it */
568
569 *where->p = where->key;
570
571 /*
572 * Update the host buffer_head or inode to point to more just allocated
573 * direct blocks blocks
574 */
575 if (num == 0 && blks > 1) {
576 current_block = le32_to_cpu(where->key) + 1;
577 for (i = 1; i < blks; i++)
578 *(where->p + i ) = cpu_to_le32(current_block++);
579 }
580
581 /*
582 * update the most recently allocated logical & physical block
583 * in i_block_alloc_info, to assist find the proper goal block for next
584 * allocation
585 */
586 if (block_i) {
587 block_i->last_alloc_logical_block = block + blks - 1;
588 block_i->last_alloc_physical_block =
589 le32_to_cpu(where[num].key) + blks - 1;
590 }
591
592 /* We are done with atomic stuff, now do the rest of housekeeping */
593
594 /* had we spliced it onto indirect block? */
595 if (where->bh)
596 mark_buffer_dirty_inode(where->bh, inode);
597
598 inode->i_ctime = current_time(inode);
599 mark_inode_dirty(inode);
600 }
601
602 /*
603 * Allocation strategy is simple: if we have to allocate something, we will
604 * have to go the whole way to leaf. So let's do it before attaching anything
605 * to tree, set linkage between the newborn blocks, write them if sync is
606 * required, recheck the path, free and repeat if check fails, otherwise
607 * set the last missing link (that will protect us from any truncate-generated
608 * removals - all blocks on the path are immune now) and possibly force the
609 * write on the parent block.
610 * That has a nice additional property: no special recovery from the failed
611 * allocations is needed - we simply release blocks and do not touch anything
612 * reachable from inode.
613 *
614 * `handle' can be NULL if create == 0.
615 *
616 * return > 0, # of blocks mapped or allocated.
617 * return = 0, if plain lookup failed.
618 * return < 0, error case.
619 */
ext2_get_blocks(struct inode * inode,sector_t iblock,unsigned long maxblocks,u32 * bno,bool * new,bool * boundary,int create)620 static int ext2_get_blocks(struct inode *inode,
621 sector_t iblock, unsigned long maxblocks,
622 u32 *bno, bool *new, bool *boundary,
623 int create)
624 {
625 int err;
626 int offsets[4];
627 Indirect chain[4];
628 Indirect *partial;
629 ext2_fsblk_t goal;
630 int indirect_blks;
631 int blocks_to_boundary = 0;
632 int depth;
633 struct ext2_inode_info *ei = EXT2_I(inode);
634 int count = 0;
635 ext2_fsblk_t first_block = 0;
636
637 BUG_ON(maxblocks == 0);
638
639 depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
640
641 if (depth == 0)
642 return -EIO;
643
644 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
645 /* Simplest case - block found, no allocation needed */
646 if (!partial) {
647 first_block = le32_to_cpu(chain[depth - 1].key);
648 count++;
649 /*map more blocks*/
650 while (count < maxblocks && count <= blocks_to_boundary) {
651 ext2_fsblk_t blk;
652
653 if (!verify_chain(chain, chain + depth - 1)) {
654 /*
655 * Indirect block might be removed by
656 * truncate while we were reading it.
657 * Handling of that case: forget what we've
658 * got now, go to reread.
659 */
660 err = -EAGAIN;
661 count = 0;
662 partial = chain + depth - 1;
663 break;
664 }
665 blk = le32_to_cpu(*(chain[depth-1].p + count));
666 if (blk == first_block + count)
667 count++;
668 else
669 break;
670 }
671 if (err != -EAGAIN)
672 goto got_it;
673 }
674
675 /* Next simple case - plain lookup or failed read of indirect block */
676 if (!create || err == -EIO)
677 goto cleanup;
678
679 mutex_lock(&ei->truncate_mutex);
680 /*
681 * If the indirect block is missing while we are reading
682 * the chain(ext2_get_branch() returns -EAGAIN err), or
683 * if the chain has been changed after we grab the semaphore,
684 * (either because another process truncated this branch, or
685 * another get_block allocated this branch) re-grab the chain to see if
686 * the request block has been allocated or not.
687 *
688 * Since we already block the truncate/other get_block
689 * at this point, we will have the current copy of the chain when we
690 * splice the branch into the tree.
691 */
692 if (err == -EAGAIN || !verify_chain(chain, partial)) {
693 while (partial > chain) {
694 brelse(partial->bh);
695 partial--;
696 }
697 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
698 if (!partial) {
699 count++;
700 mutex_unlock(&ei->truncate_mutex);
701 goto got_it;
702 }
703
704 if (err) {
705 mutex_unlock(&ei->truncate_mutex);
706 goto cleanup;
707 }
708 }
709
710 /*
711 * Okay, we need to do block allocation. Lazily initialize the block
712 * allocation info here if necessary
713 */
714 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
715 ext2_init_block_alloc_info(inode);
716
717 goal = ext2_find_goal(inode, iblock, partial);
718
719 /* the number of blocks need to allocate for [d,t]indirect blocks */
720 indirect_blks = (chain + depth) - partial - 1;
721 /*
722 * Next look up the indirect map to count the total number of
723 * direct blocks to allocate for this branch.
724 */
725 count = ext2_blks_to_allocate(partial, indirect_blks,
726 maxblocks, blocks_to_boundary);
727 /*
728 * XXX ???? Block out ext2_truncate while we alter the tree
729 */
730 err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
731 offsets + (partial - chain), partial);
732
733 if (err) {
734 mutex_unlock(&ei->truncate_mutex);
735 goto cleanup;
736 }
737
738 if (IS_DAX(inode)) {
739 /*
740 * We must unmap blocks before zeroing so that writeback cannot
741 * overwrite zeros with stale data from block device page cache.
742 */
743 clean_bdev_aliases(inode->i_sb->s_bdev,
744 le32_to_cpu(chain[depth-1].key),
745 count);
746 /*
747 * block must be initialised before we put it in the tree
748 * so that it's not found by another thread before it's
749 * initialised
750 */
751 err = sb_issue_zeroout(inode->i_sb,
752 le32_to_cpu(chain[depth-1].key), count,
753 GFP_NOFS);
754 if (err) {
755 mutex_unlock(&ei->truncate_mutex);
756 goto cleanup;
757 }
758 }
759 *new = true;
760
761 ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
762 mutex_unlock(&ei->truncate_mutex);
763 got_it:
764 if (count > blocks_to_boundary)
765 *boundary = true;
766 err = count;
767 /* Clean up and exit */
768 partial = chain + depth - 1; /* the whole chain */
769 cleanup:
770 while (partial > chain) {
771 brelse(partial->bh);
772 partial--;
773 }
774 if (err > 0)
775 *bno = le32_to_cpu(chain[depth-1].key);
776 return err;
777 }
778
ext2_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)779 int ext2_get_block(struct inode *inode, sector_t iblock,
780 struct buffer_head *bh_result, int create)
781 {
782 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
783 bool new = false, boundary = false;
784 u32 bno;
785 int ret;
786
787 ret = ext2_get_blocks(inode, iblock, max_blocks, &bno, &new, &boundary,
788 create);
789 if (ret <= 0)
790 return ret;
791
792 map_bh(bh_result, inode->i_sb, bno);
793 bh_result->b_size = (ret << inode->i_blkbits);
794 if (new)
795 set_buffer_new(bh_result);
796 if (boundary)
797 set_buffer_boundary(bh_result);
798 return 0;
799
800 }
801
ext2_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)802 static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
803 unsigned flags, struct iomap *iomap, struct iomap *srcmap)
804 {
805 unsigned int blkbits = inode->i_blkbits;
806 unsigned long first_block = offset >> blkbits;
807 unsigned long max_blocks = (length + (1 << blkbits) - 1) >> blkbits;
808 struct ext2_sb_info *sbi = EXT2_SB(inode->i_sb);
809 bool new = false, boundary = false;
810 u32 bno;
811 int ret;
812
813 ret = ext2_get_blocks(inode, first_block, max_blocks,
814 &bno, &new, &boundary, flags & IOMAP_WRITE);
815 if (ret < 0)
816 return ret;
817
818 iomap->flags = 0;
819 iomap->offset = (u64)first_block << blkbits;
820 if (flags & IOMAP_DAX)
821 iomap->dax_dev = sbi->s_daxdev;
822 else
823 iomap->bdev = inode->i_sb->s_bdev;
824
825 if (ret == 0) {
826 iomap->type = IOMAP_HOLE;
827 iomap->addr = IOMAP_NULL_ADDR;
828 iomap->length = 1 << blkbits;
829 } else {
830 iomap->type = IOMAP_MAPPED;
831 iomap->addr = (u64)bno << blkbits;
832 if (flags & IOMAP_DAX)
833 iomap->addr += sbi->s_dax_part_off;
834 iomap->length = (u64)ret << blkbits;
835 iomap->flags |= IOMAP_F_MERGED;
836 }
837
838 if (new)
839 iomap->flags |= IOMAP_F_NEW;
840 return 0;
841 }
842
843 static int
ext2_iomap_end(struct inode * inode,loff_t offset,loff_t length,ssize_t written,unsigned flags,struct iomap * iomap)844 ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
845 ssize_t written, unsigned flags, struct iomap *iomap)
846 {
847 if (iomap->type == IOMAP_MAPPED &&
848 written < length &&
849 (flags & IOMAP_WRITE))
850 ext2_write_failed(inode->i_mapping, offset + length);
851 return 0;
852 }
853
854 const struct iomap_ops ext2_iomap_ops = {
855 .iomap_begin = ext2_iomap_begin,
856 .iomap_end = ext2_iomap_end,
857 };
858
ext2_fiemap(struct inode * inode,struct fiemap_extent_info * fieinfo,u64 start,u64 len)859 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
860 u64 start, u64 len)
861 {
862 int ret;
863
864 inode_lock(inode);
865 len = min_t(u64, len, i_size_read(inode));
866 ret = iomap_fiemap(inode, fieinfo, start, len, &ext2_iomap_ops);
867 inode_unlock(inode);
868
869 return ret;
870 }
871
ext2_writepage(struct page * page,struct writeback_control * wbc)872 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
873 {
874 return block_write_full_page(page, ext2_get_block, wbc);
875 }
876
ext2_read_folio(struct file * file,struct folio * folio)877 static int ext2_read_folio(struct file *file, struct folio *folio)
878 {
879 return mpage_read_folio(folio, ext2_get_block);
880 }
881
ext2_readahead(struct readahead_control * rac)882 static void ext2_readahead(struct readahead_control *rac)
883 {
884 mpage_readahead(rac, ext2_get_block);
885 }
886
887 static int
ext2_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)888 ext2_write_begin(struct file *file, struct address_space *mapping,
889 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
890 {
891 int ret;
892
893 ret = block_write_begin(mapping, pos, len, pagep, ext2_get_block);
894 if (ret < 0)
895 ext2_write_failed(mapping, pos + len);
896 return ret;
897 }
898
ext2_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)899 static int ext2_write_end(struct file *file, struct address_space *mapping,
900 loff_t pos, unsigned len, unsigned copied,
901 struct page *page, void *fsdata)
902 {
903 int ret;
904
905 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
906 if (ret < len)
907 ext2_write_failed(mapping, pos + len);
908 return ret;
909 }
910
ext2_bmap(struct address_space * mapping,sector_t block)911 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
912 {
913 return generic_block_bmap(mapping,block,ext2_get_block);
914 }
915
916 static ssize_t
ext2_direct_IO(struct kiocb * iocb,struct iov_iter * iter)917 ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
918 {
919 struct file *file = iocb->ki_filp;
920 struct address_space *mapping = file->f_mapping;
921 struct inode *inode = mapping->host;
922 size_t count = iov_iter_count(iter);
923 loff_t offset = iocb->ki_pos;
924 ssize_t ret;
925
926 ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
927 if (ret < 0 && iov_iter_rw(iter) == WRITE)
928 ext2_write_failed(mapping, offset + count);
929 return ret;
930 }
931
932 static int
ext2_writepages(struct address_space * mapping,struct writeback_control * wbc)933 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
934 {
935 return mpage_writepages(mapping, wbc, ext2_get_block);
936 }
937
938 static int
ext2_dax_writepages(struct address_space * mapping,struct writeback_control * wbc)939 ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
940 {
941 struct ext2_sb_info *sbi = EXT2_SB(mapping->host->i_sb);
942
943 return dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
944 }
945
946 const struct address_space_operations ext2_aops = {
947 .dirty_folio = block_dirty_folio,
948 .invalidate_folio = block_invalidate_folio,
949 .read_folio = ext2_read_folio,
950 .readahead = ext2_readahead,
951 .writepage = ext2_writepage,
952 .write_begin = ext2_write_begin,
953 .write_end = ext2_write_end,
954 .bmap = ext2_bmap,
955 .direct_IO = ext2_direct_IO,
956 .writepages = ext2_writepages,
957 .migrate_folio = buffer_migrate_folio,
958 .is_partially_uptodate = block_is_partially_uptodate,
959 .error_remove_page = generic_error_remove_page,
960 };
961
962 static const struct address_space_operations ext2_dax_aops = {
963 .writepages = ext2_dax_writepages,
964 .direct_IO = noop_direct_IO,
965 .dirty_folio = noop_dirty_folio,
966 };
967
968 /*
969 * Probably it should be a library function... search for first non-zero word
970 * or memcmp with zero_page, whatever is better for particular architecture.
971 * Linus?
972 */
all_zeroes(__le32 * p,__le32 * q)973 static inline int all_zeroes(__le32 *p, __le32 *q)
974 {
975 while (p < q)
976 if (*p++)
977 return 0;
978 return 1;
979 }
980
981 /**
982 * ext2_find_shared - find the indirect blocks for partial truncation.
983 * @inode: inode in question
984 * @depth: depth of the affected branch
985 * @offsets: offsets of pointers in that branch (see ext2_block_to_path)
986 * @chain: place to store the pointers to partial indirect blocks
987 * @top: place to the (detached) top of branch
988 *
989 * This is a helper function used by ext2_truncate().
990 *
991 * When we do truncate() we may have to clean the ends of several indirect
992 * blocks but leave the blocks themselves alive. Block is partially
993 * truncated if some data below the new i_size is referred from it (and
994 * it is on the path to the first completely truncated data block, indeed).
995 * We have to free the top of that path along with everything to the right
996 * of the path. Since no allocation past the truncation point is possible
997 * until ext2_truncate() finishes, we may safely do the latter, but top
998 * of branch may require special attention - pageout below the truncation
999 * point might try to populate it.
1000 *
1001 * We atomically detach the top of branch from the tree, store the block
1002 * number of its root in *@top, pointers to buffer_heads of partially
1003 * truncated blocks - in @chain[].bh and pointers to their last elements
1004 * that should not be removed - in @chain[].p. Return value is the pointer
1005 * to last filled element of @chain.
1006 *
1007 * The work left to caller to do the actual freeing of subtrees:
1008 * a) free the subtree starting from *@top
1009 * b) free the subtrees whose roots are stored in
1010 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
1011 * c) free the subtrees growing from the inode past the @chain[0].p
1012 * (no partially truncated stuff there).
1013 */
1014
ext2_find_shared(struct inode * inode,int depth,int offsets[4],Indirect chain[4],__le32 * top)1015 static Indirect *ext2_find_shared(struct inode *inode,
1016 int depth,
1017 int offsets[4],
1018 Indirect chain[4],
1019 __le32 *top)
1020 {
1021 Indirect *partial, *p;
1022 int k, err;
1023
1024 *top = 0;
1025 for (k = depth; k > 1 && !offsets[k-1]; k--)
1026 ;
1027 partial = ext2_get_branch(inode, k, offsets, chain, &err);
1028 if (!partial)
1029 partial = chain + k-1;
1030 /*
1031 * If the branch acquired continuation since we've looked at it -
1032 * fine, it should all survive and (new) top doesn't belong to us.
1033 */
1034 write_lock(&EXT2_I(inode)->i_meta_lock);
1035 if (!partial->key && *partial->p) {
1036 write_unlock(&EXT2_I(inode)->i_meta_lock);
1037 goto no_top;
1038 }
1039 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
1040 ;
1041 /*
1042 * OK, we've found the last block that must survive. The rest of our
1043 * branch should be detached before unlocking. However, if that rest
1044 * of branch is all ours and does not grow immediately from the inode
1045 * it's easier to cheat and just decrement partial->p.
1046 */
1047 if (p == chain + k - 1 && p > chain) {
1048 p->p--;
1049 } else {
1050 *top = *p->p;
1051 *p->p = 0;
1052 }
1053 write_unlock(&EXT2_I(inode)->i_meta_lock);
1054
1055 while(partial > p)
1056 {
1057 brelse(partial->bh);
1058 partial--;
1059 }
1060 no_top:
1061 return partial;
1062 }
1063
1064 /**
1065 * ext2_free_data - free a list of data blocks
1066 * @inode: inode we are dealing with
1067 * @p: array of block numbers
1068 * @q: points immediately past the end of array
1069 *
1070 * We are freeing all blocks referred from that array (numbers are
1071 * stored as little-endian 32-bit) and updating @inode->i_blocks
1072 * appropriately.
1073 */
ext2_free_data(struct inode * inode,__le32 * p,__le32 * q)1074 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1075 {
1076 unsigned long block_to_free = 0, count = 0;
1077 unsigned long nr;
1078
1079 for ( ; p < q ; p++) {
1080 nr = le32_to_cpu(*p);
1081 if (nr) {
1082 *p = 0;
1083 /* accumulate blocks to free if they're contiguous */
1084 if (count == 0)
1085 goto free_this;
1086 else if (block_to_free == nr - count)
1087 count++;
1088 else {
1089 ext2_free_blocks (inode, block_to_free, count);
1090 mark_inode_dirty(inode);
1091 free_this:
1092 block_to_free = nr;
1093 count = 1;
1094 }
1095 }
1096 }
1097 if (count > 0) {
1098 ext2_free_blocks (inode, block_to_free, count);
1099 mark_inode_dirty(inode);
1100 }
1101 }
1102
1103 /**
1104 * ext2_free_branches - free an array of branches
1105 * @inode: inode we are dealing with
1106 * @p: array of block numbers
1107 * @q: pointer immediately past the end of array
1108 * @depth: depth of the branches to free
1109 *
1110 * We are freeing all blocks referred from these branches (numbers are
1111 * stored as little-endian 32-bit) and updating @inode->i_blocks
1112 * appropriately.
1113 */
ext2_free_branches(struct inode * inode,__le32 * p,__le32 * q,int depth)1114 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1115 {
1116 struct buffer_head * bh;
1117 unsigned long nr;
1118
1119 if (depth--) {
1120 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1121 for ( ; p < q ; p++) {
1122 nr = le32_to_cpu(*p);
1123 if (!nr)
1124 continue;
1125 *p = 0;
1126 bh = sb_bread(inode->i_sb, nr);
1127 /*
1128 * A read failure? Report error and clear slot
1129 * (should be rare).
1130 */
1131 if (!bh) {
1132 ext2_error(inode->i_sb, "ext2_free_branches",
1133 "Read failure, inode=%ld, block=%ld",
1134 inode->i_ino, nr);
1135 continue;
1136 }
1137 ext2_free_branches(inode,
1138 (__le32*)bh->b_data,
1139 (__le32*)bh->b_data + addr_per_block,
1140 depth);
1141 bforget(bh);
1142 ext2_free_blocks(inode, nr, 1);
1143 mark_inode_dirty(inode);
1144 }
1145 } else
1146 ext2_free_data(inode, p, q);
1147 }
1148
1149 /* mapping->invalidate_lock must be held when calling this function */
__ext2_truncate_blocks(struct inode * inode,loff_t offset)1150 static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1151 {
1152 __le32 *i_data = EXT2_I(inode)->i_data;
1153 struct ext2_inode_info *ei = EXT2_I(inode);
1154 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1155 int offsets[4];
1156 Indirect chain[4];
1157 Indirect *partial;
1158 __le32 nr = 0;
1159 int n;
1160 long iblock;
1161 unsigned blocksize;
1162 blocksize = inode->i_sb->s_blocksize;
1163 iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1164
1165 #ifdef CONFIG_FS_DAX
1166 WARN_ON(!rwsem_is_locked(&inode->i_mapping->invalidate_lock));
1167 #endif
1168
1169 n = ext2_block_to_path(inode, iblock, offsets, NULL);
1170 if (n == 0)
1171 return;
1172
1173 /*
1174 * From here we block out all ext2_get_block() callers who want to
1175 * modify the block allocation tree.
1176 */
1177 mutex_lock(&ei->truncate_mutex);
1178
1179 if (n == 1) {
1180 ext2_free_data(inode, i_data+offsets[0],
1181 i_data + EXT2_NDIR_BLOCKS);
1182 goto do_indirects;
1183 }
1184
1185 partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1186 /* Kill the top of shared branch (already detached) */
1187 if (nr) {
1188 if (partial == chain)
1189 mark_inode_dirty(inode);
1190 else
1191 mark_buffer_dirty_inode(partial->bh, inode);
1192 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1193 }
1194 /* Clear the ends of indirect blocks on the shared branch */
1195 while (partial > chain) {
1196 ext2_free_branches(inode,
1197 partial->p + 1,
1198 (__le32*)partial->bh->b_data+addr_per_block,
1199 (chain+n-1) - partial);
1200 mark_buffer_dirty_inode(partial->bh, inode);
1201 brelse (partial->bh);
1202 partial--;
1203 }
1204 do_indirects:
1205 /* Kill the remaining (whole) subtrees */
1206 switch (offsets[0]) {
1207 default:
1208 nr = i_data[EXT2_IND_BLOCK];
1209 if (nr) {
1210 i_data[EXT2_IND_BLOCK] = 0;
1211 mark_inode_dirty(inode);
1212 ext2_free_branches(inode, &nr, &nr+1, 1);
1213 }
1214 fallthrough;
1215 case EXT2_IND_BLOCK:
1216 nr = i_data[EXT2_DIND_BLOCK];
1217 if (nr) {
1218 i_data[EXT2_DIND_BLOCK] = 0;
1219 mark_inode_dirty(inode);
1220 ext2_free_branches(inode, &nr, &nr+1, 2);
1221 }
1222 fallthrough;
1223 case EXT2_DIND_BLOCK:
1224 nr = i_data[EXT2_TIND_BLOCK];
1225 if (nr) {
1226 i_data[EXT2_TIND_BLOCK] = 0;
1227 mark_inode_dirty(inode);
1228 ext2_free_branches(inode, &nr, &nr+1, 3);
1229 }
1230 break;
1231 case EXT2_TIND_BLOCK:
1232 ;
1233 }
1234
1235 ext2_discard_reservation(inode);
1236
1237 mutex_unlock(&ei->truncate_mutex);
1238 }
1239
ext2_truncate_blocks(struct inode * inode,loff_t offset)1240 static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1241 {
1242 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1243 S_ISLNK(inode->i_mode)))
1244 return;
1245 if (ext2_inode_is_fast_symlink(inode))
1246 return;
1247
1248 filemap_invalidate_lock(inode->i_mapping);
1249 __ext2_truncate_blocks(inode, offset);
1250 filemap_invalidate_unlock(inode->i_mapping);
1251 }
1252
ext2_setsize(struct inode * inode,loff_t newsize)1253 static int ext2_setsize(struct inode *inode, loff_t newsize)
1254 {
1255 int error;
1256
1257 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1258 S_ISLNK(inode->i_mode)))
1259 return -EINVAL;
1260 if (ext2_inode_is_fast_symlink(inode))
1261 return -EINVAL;
1262 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1263 return -EPERM;
1264
1265 inode_dio_wait(inode);
1266
1267 if (IS_DAX(inode))
1268 error = dax_zero_range(inode, newsize,
1269 PAGE_ALIGN(newsize) - newsize, NULL,
1270 &ext2_iomap_ops);
1271 else
1272 error = block_truncate_page(inode->i_mapping,
1273 newsize, ext2_get_block);
1274 if (error)
1275 return error;
1276
1277 filemap_invalidate_lock(inode->i_mapping);
1278 truncate_setsize(inode, newsize);
1279 __ext2_truncate_blocks(inode, newsize);
1280 filemap_invalidate_unlock(inode->i_mapping);
1281
1282 inode->i_mtime = inode->i_ctime = current_time(inode);
1283 if (inode_needs_sync(inode)) {
1284 sync_mapping_buffers(inode->i_mapping);
1285 sync_inode_metadata(inode, 1);
1286 } else {
1287 mark_inode_dirty(inode);
1288 }
1289
1290 return 0;
1291 }
1292
ext2_get_inode(struct super_block * sb,ino_t ino,struct buffer_head ** p)1293 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1294 struct buffer_head **p)
1295 {
1296 struct buffer_head * bh;
1297 unsigned long block_group;
1298 unsigned long block;
1299 unsigned long offset;
1300 struct ext2_group_desc * gdp;
1301
1302 *p = NULL;
1303 if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1304 ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1305 goto Einval;
1306
1307 block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1308 gdp = ext2_get_group_desc(sb, block_group, NULL);
1309 if (!gdp)
1310 goto Egdp;
1311 /*
1312 * Figure out the offset within the block group inode table
1313 */
1314 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1315 block = le32_to_cpu(gdp->bg_inode_table) +
1316 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1317 if (!(bh = sb_bread(sb, block)))
1318 goto Eio;
1319
1320 *p = bh;
1321 offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1322 return (struct ext2_inode *) (bh->b_data + offset);
1323
1324 Einval:
1325 ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1326 (unsigned long) ino);
1327 return ERR_PTR(-EINVAL);
1328 Eio:
1329 ext2_error(sb, "ext2_get_inode",
1330 "unable to read inode block - inode=%lu, block=%lu",
1331 (unsigned long) ino, block);
1332 Egdp:
1333 return ERR_PTR(-EIO);
1334 }
1335
ext2_set_inode_flags(struct inode * inode)1336 void ext2_set_inode_flags(struct inode *inode)
1337 {
1338 unsigned int flags = EXT2_I(inode)->i_flags;
1339
1340 inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1341 S_DIRSYNC | S_DAX);
1342 if (flags & EXT2_SYNC_FL)
1343 inode->i_flags |= S_SYNC;
1344 if (flags & EXT2_APPEND_FL)
1345 inode->i_flags |= S_APPEND;
1346 if (flags & EXT2_IMMUTABLE_FL)
1347 inode->i_flags |= S_IMMUTABLE;
1348 if (flags & EXT2_NOATIME_FL)
1349 inode->i_flags |= S_NOATIME;
1350 if (flags & EXT2_DIRSYNC_FL)
1351 inode->i_flags |= S_DIRSYNC;
1352 if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1353 inode->i_flags |= S_DAX;
1354 }
1355
ext2_set_file_ops(struct inode * inode)1356 void ext2_set_file_ops(struct inode *inode)
1357 {
1358 inode->i_op = &ext2_file_inode_operations;
1359 inode->i_fop = &ext2_file_operations;
1360 if (IS_DAX(inode))
1361 inode->i_mapping->a_ops = &ext2_dax_aops;
1362 else
1363 inode->i_mapping->a_ops = &ext2_aops;
1364 }
1365
ext2_iget(struct super_block * sb,unsigned long ino)1366 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1367 {
1368 struct ext2_inode_info *ei;
1369 struct buffer_head * bh = NULL;
1370 struct ext2_inode *raw_inode;
1371 struct inode *inode;
1372 long ret = -EIO;
1373 int n;
1374 uid_t i_uid;
1375 gid_t i_gid;
1376
1377 inode = iget_locked(sb, ino);
1378 if (!inode)
1379 return ERR_PTR(-ENOMEM);
1380 if (!(inode->i_state & I_NEW))
1381 return inode;
1382
1383 ei = EXT2_I(inode);
1384 ei->i_block_alloc_info = NULL;
1385
1386 raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1387 if (IS_ERR(raw_inode)) {
1388 ret = PTR_ERR(raw_inode);
1389 goto bad_inode;
1390 }
1391
1392 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1393 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1394 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1395 if (!(test_opt (inode->i_sb, NO_UID32))) {
1396 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1397 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1398 }
1399 i_uid_write(inode, i_uid);
1400 i_gid_write(inode, i_gid);
1401 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1402 inode->i_size = le32_to_cpu(raw_inode->i_size);
1403 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1404 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1405 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1406 inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1407 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1408 /* We now have enough fields to check if the inode was active or not.
1409 * This is needed because nfsd might try to access dead inodes
1410 * the test is that same one that e2fsck uses
1411 * NeilBrown 1999oct15
1412 */
1413 if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1414 /* this inode is deleted */
1415 ret = -ESTALE;
1416 goto bad_inode;
1417 }
1418 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1419 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1420 ext2_set_inode_flags(inode);
1421 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1422 ei->i_frag_no = raw_inode->i_frag;
1423 ei->i_frag_size = raw_inode->i_fsize;
1424 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1425 ei->i_dir_acl = 0;
1426
1427 if (ei->i_file_acl &&
1428 !ext2_data_block_valid(EXT2_SB(sb), ei->i_file_acl, 1)) {
1429 ext2_error(sb, "ext2_iget", "bad extended attribute block %u",
1430 ei->i_file_acl);
1431 ret = -EFSCORRUPTED;
1432 goto bad_inode;
1433 }
1434
1435 if (S_ISREG(inode->i_mode))
1436 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1437 else
1438 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1439 if (i_size_read(inode) < 0) {
1440 ret = -EFSCORRUPTED;
1441 goto bad_inode;
1442 }
1443 ei->i_dtime = 0;
1444 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1445 ei->i_state = 0;
1446 ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1447 ei->i_dir_start_lookup = 0;
1448
1449 /*
1450 * NOTE! The in-memory inode i_data array is in little-endian order
1451 * even on big-endian machines: we do NOT byteswap the block numbers!
1452 */
1453 for (n = 0; n < EXT2_N_BLOCKS; n++)
1454 ei->i_data[n] = raw_inode->i_block[n];
1455
1456 if (S_ISREG(inode->i_mode)) {
1457 ext2_set_file_ops(inode);
1458 } else if (S_ISDIR(inode->i_mode)) {
1459 inode->i_op = &ext2_dir_inode_operations;
1460 inode->i_fop = &ext2_dir_operations;
1461 inode->i_mapping->a_ops = &ext2_aops;
1462 } else if (S_ISLNK(inode->i_mode)) {
1463 if (ext2_inode_is_fast_symlink(inode)) {
1464 inode->i_link = (char *)ei->i_data;
1465 inode->i_op = &ext2_fast_symlink_inode_operations;
1466 nd_terminate_link(ei->i_data, inode->i_size,
1467 sizeof(ei->i_data) - 1);
1468 } else {
1469 inode->i_op = &ext2_symlink_inode_operations;
1470 inode_nohighmem(inode);
1471 inode->i_mapping->a_ops = &ext2_aops;
1472 }
1473 } else {
1474 inode->i_op = &ext2_special_inode_operations;
1475 if (raw_inode->i_block[0])
1476 init_special_inode(inode, inode->i_mode,
1477 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1478 else
1479 init_special_inode(inode, inode->i_mode,
1480 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1481 }
1482 brelse (bh);
1483 unlock_new_inode(inode);
1484 return inode;
1485
1486 bad_inode:
1487 brelse(bh);
1488 iget_failed(inode);
1489 return ERR_PTR(ret);
1490 }
1491
__ext2_write_inode(struct inode * inode,int do_sync)1492 static int __ext2_write_inode(struct inode *inode, int do_sync)
1493 {
1494 struct ext2_inode_info *ei = EXT2_I(inode);
1495 struct super_block *sb = inode->i_sb;
1496 ino_t ino = inode->i_ino;
1497 uid_t uid = i_uid_read(inode);
1498 gid_t gid = i_gid_read(inode);
1499 struct buffer_head * bh;
1500 struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1501 int n;
1502 int err = 0;
1503
1504 if (IS_ERR(raw_inode))
1505 return -EIO;
1506
1507 /* For fields not tracking in the in-memory inode,
1508 * initialise them to zero for new inodes. */
1509 if (ei->i_state & EXT2_STATE_NEW)
1510 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1511
1512 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1513 if (!(test_opt(sb, NO_UID32))) {
1514 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1515 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1516 /*
1517 * Fix up interoperability with old kernels. Otherwise, old inodes get
1518 * re-used with the upper 16 bits of the uid/gid intact
1519 */
1520 if (!ei->i_dtime) {
1521 raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1522 raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1523 } else {
1524 raw_inode->i_uid_high = 0;
1525 raw_inode->i_gid_high = 0;
1526 }
1527 } else {
1528 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1529 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1530 raw_inode->i_uid_high = 0;
1531 raw_inode->i_gid_high = 0;
1532 }
1533 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1534 raw_inode->i_size = cpu_to_le32(inode->i_size);
1535 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1536 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1537 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1538
1539 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1540 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1541 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1542 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1543 raw_inode->i_frag = ei->i_frag_no;
1544 raw_inode->i_fsize = ei->i_frag_size;
1545 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1546 if (!S_ISREG(inode->i_mode))
1547 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1548 else {
1549 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1550 if (inode->i_size > 0x7fffffffULL) {
1551 if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1552 EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1553 EXT2_SB(sb)->s_es->s_rev_level ==
1554 cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1555 /* If this is the first large file
1556 * created, add a flag to the superblock.
1557 */
1558 spin_lock(&EXT2_SB(sb)->s_lock);
1559 ext2_update_dynamic_rev(sb);
1560 EXT2_SET_RO_COMPAT_FEATURE(sb,
1561 EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1562 spin_unlock(&EXT2_SB(sb)->s_lock);
1563 ext2_sync_super(sb, EXT2_SB(sb)->s_es, 1);
1564 }
1565 }
1566 }
1567
1568 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1569 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1570 if (old_valid_dev(inode->i_rdev)) {
1571 raw_inode->i_block[0] =
1572 cpu_to_le32(old_encode_dev(inode->i_rdev));
1573 raw_inode->i_block[1] = 0;
1574 } else {
1575 raw_inode->i_block[0] = 0;
1576 raw_inode->i_block[1] =
1577 cpu_to_le32(new_encode_dev(inode->i_rdev));
1578 raw_inode->i_block[2] = 0;
1579 }
1580 } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1581 raw_inode->i_block[n] = ei->i_data[n];
1582 mark_buffer_dirty(bh);
1583 if (do_sync) {
1584 sync_dirty_buffer(bh);
1585 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1586 printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1587 sb->s_id, (unsigned long) ino);
1588 err = -EIO;
1589 }
1590 }
1591 ei->i_state &= ~EXT2_STATE_NEW;
1592 brelse (bh);
1593 return err;
1594 }
1595
ext2_write_inode(struct inode * inode,struct writeback_control * wbc)1596 int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1597 {
1598 return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1599 }
1600
ext2_getattr(struct user_namespace * mnt_userns,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)1601 int ext2_getattr(struct user_namespace *mnt_userns, const struct path *path,
1602 struct kstat *stat, u32 request_mask, unsigned int query_flags)
1603 {
1604 struct inode *inode = d_inode(path->dentry);
1605 struct ext2_inode_info *ei = EXT2_I(inode);
1606 unsigned int flags;
1607
1608 flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
1609 if (flags & EXT2_APPEND_FL)
1610 stat->attributes |= STATX_ATTR_APPEND;
1611 if (flags & EXT2_COMPR_FL)
1612 stat->attributes |= STATX_ATTR_COMPRESSED;
1613 if (flags & EXT2_IMMUTABLE_FL)
1614 stat->attributes |= STATX_ATTR_IMMUTABLE;
1615 if (flags & EXT2_NODUMP_FL)
1616 stat->attributes |= STATX_ATTR_NODUMP;
1617 stat->attributes_mask |= (STATX_ATTR_APPEND |
1618 STATX_ATTR_COMPRESSED |
1619 STATX_ATTR_ENCRYPTED |
1620 STATX_ATTR_IMMUTABLE |
1621 STATX_ATTR_NODUMP);
1622
1623 generic_fillattr(&init_user_ns, inode, stat);
1624 return 0;
1625 }
1626
ext2_setattr(struct user_namespace * mnt_userns,struct dentry * dentry,struct iattr * iattr)1627 int ext2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
1628 struct iattr *iattr)
1629 {
1630 struct inode *inode = d_inode(dentry);
1631 int error;
1632
1633 error = setattr_prepare(&init_user_ns, dentry, iattr);
1634 if (error)
1635 return error;
1636
1637 if (is_quota_modification(mnt_userns, inode, iattr)) {
1638 error = dquot_initialize(inode);
1639 if (error)
1640 return error;
1641 }
1642 if (i_uid_needs_update(mnt_userns, iattr, inode) ||
1643 i_gid_needs_update(mnt_userns, iattr, inode)) {
1644 error = dquot_transfer(mnt_userns, inode, iattr);
1645 if (error)
1646 return error;
1647 }
1648 if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1649 error = ext2_setsize(inode, iattr->ia_size);
1650 if (error)
1651 return error;
1652 }
1653 setattr_copy(&init_user_ns, inode, iattr);
1654 if (iattr->ia_valid & ATTR_MODE)
1655 error = posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
1656 mark_inode_dirty(inode);
1657
1658 return error;
1659 }
1660