1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) International Business Machines Corp., 2000-2004
4  *   Portions Copyright (C) Tino Reichardt, 2012
5  */
6 
7 #include <linux/fs.h>
8 #include <linux/slab.h>
9 #include "jfs_incore.h"
10 #include "jfs_superblock.h"
11 #include "jfs_dmap.h"
12 #include "jfs_imap.h"
13 #include "jfs_lock.h"
14 #include "jfs_metapage.h"
15 #include "jfs_debug.h"
16 #include "jfs_discard.h"
17 
18 /*
19  *	SERIALIZATION of the Block Allocation Map.
20  *
21  *	the working state of the block allocation map is accessed in
22  *	two directions:
23  *
24  *	1) allocation and free requests that start at the dmap
25  *	   level and move up through the dmap control pages (i.e.
26  *	   the vast majority of requests).
27  *
28  *	2) allocation requests that start at dmap control page
29  *	   level and work down towards the dmaps.
30  *
31  *	the serialization scheme used here is as follows.
32  *
33  *	requests which start at the bottom are serialized against each
34  *	other through buffers and each requests holds onto its buffers
35  *	as it works it way up from a single dmap to the required level
36  *	of dmap control page.
37  *	requests that start at the top are serialized against each other
38  *	and request that start from the bottom by the multiple read/single
39  *	write inode lock of the bmap inode. requests starting at the top
40  *	take this lock in write mode while request starting at the bottom
41  *	take the lock in read mode.  a single top-down request may proceed
42  *	exclusively while multiple bottoms-up requests may proceed
43  *	simultaneously (under the protection of busy buffers).
44  *
45  *	in addition to information found in dmaps and dmap control pages,
46  *	the working state of the block allocation map also includes read/
47  *	write information maintained in the bmap descriptor (i.e. total
48  *	free block count, allocation group level free block counts).
49  *	a single exclusive lock (BMAP_LOCK) is used to guard this information
50  *	in the face of multiple-bottoms up requests.
51  *	(lock ordering: IREAD_LOCK, BMAP_LOCK);
52  *
53  *	accesses to the persistent state of the block allocation map (limited
54  *	to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
55  */
56 
57 #define BMAP_LOCK_INIT(bmp)	mutex_init(&bmp->db_bmaplock)
58 #define BMAP_LOCK(bmp)		mutex_lock(&bmp->db_bmaplock)
59 #define BMAP_UNLOCK(bmp)	mutex_unlock(&bmp->db_bmaplock)
60 
61 /*
62  * forward references
63  */
64 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
65 			int nblocks);
66 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
67 static int dbBackSplit(dmtree_t * tp, int leafno);
68 static int dbJoin(dmtree_t * tp, int leafno, int newval);
69 static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
70 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
71 		    int level);
72 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
73 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
74 		       int nblocks);
75 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
76 		       int nblocks,
77 		       int l2nb, s64 * results);
78 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
79 		       int nblocks);
80 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
81 			  int l2nb,
82 			  s64 * results);
83 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
84 		     s64 * results);
85 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
86 		      s64 * results);
87 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
88 static int dbFindBits(u32 word, int l2nb);
89 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
90 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
91 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
92 		      int nblocks);
93 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
94 		      int nblocks);
95 static int dbMaxBud(u8 * cp);
96 static int blkstol2(s64 nb);
97 
98 static int cntlz(u32 value);
99 static int cnttz(u32 word);
100 
101 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
102 			 int nblocks);
103 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
104 static int dbInitDmapTree(struct dmap * dp);
105 static int dbInitTree(struct dmaptree * dtp);
106 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
107 static int dbGetL2AGSize(s64 nblocks);
108 
109 /*
110  *	buddy table
111  *
112  * table used for determining buddy sizes within characters of
113  * dmap bitmap words.  the characters themselves serve as indexes
114  * into the table, with the table elements yielding the maximum
115  * binary buddy of free bits within the character.
116  */
117 static const s8 budtab[256] = {
118 	3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
119 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
120 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
121 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
122 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
123 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
124 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
125 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
126 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
127 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
128 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
129 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
130 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
131 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
132 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
133 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
134 };
135 
136 /*
137  * NAME:	dbMount()
138  *
139  * FUNCTION:	initializate the block allocation map.
140  *
141  *		memory is allocated for the in-core bmap descriptor and
142  *		the in-core descriptor is initialized from disk.
143  *
144  * PARAMETERS:
145  *	ipbmap	- pointer to in-core inode for the block map.
146  *
147  * RETURN VALUES:
148  *	0	- success
149  *	-ENOMEM	- insufficient memory
150  *	-EIO	- i/o error
151  *	-EINVAL - wrong bmap data
152  */
dbMount(struct inode * ipbmap)153 int dbMount(struct inode *ipbmap)
154 {
155 	struct bmap *bmp;
156 	struct dbmap_disk *dbmp_le;
157 	struct metapage *mp;
158 	int i, err;
159 
160 	/*
161 	 * allocate/initialize the in-memory bmap descriptor
162 	 */
163 	/* allocate memory for the in-memory bmap descriptor */
164 	bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
165 	if (bmp == NULL)
166 		return -ENOMEM;
167 
168 	/* read the on-disk bmap descriptor. */
169 	mp = read_metapage(ipbmap,
170 			   BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
171 			   PSIZE, 0);
172 	if (mp == NULL) {
173 		err = -EIO;
174 		goto err_kfree_bmp;
175 	}
176 
177 	/* copy the on-disk bmap descriptor to its in-memory version. */
178 	dbmp_le = (struct dbmap_disk *) mp->data;
179 	bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
180 	bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
181 	bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
182 	bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
183 	if (!bmp->db_numag) {
184 		err = -EINVAL;
185 		goto err_release_metapage;
186 	}
187 
188 	bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
189 	bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
190 	bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
191 	bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
192 	bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
193 	bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
194 	bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
195 	bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
196 	if (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG) {
197 		err = -EINVAL;
198 		goto err_release_metapage;
199 	}
200 
201 	if (((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) {
202 		err = -EINVAL;
203 		goto err_release_metapage;
204 	}
205 
206 	for (i = 0; i < MAXAG; i++)
207 		bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
208 	bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
209 	bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
210 
211 	/* release the buffer. */
212 	release_metapage(mp);
213 
214 	/* bind the bmap inode and the bmap descriptor to each other. */
215 	bmp->db_ipbmap = ipbmap;
216 	JFS_SBI(ipbmap->i_sb)->bmap = bmp;
217 
218 	memset(bmp->db_active, 0, sizeof(bmp->db_active));
219 
220 	/*
221 	 * allocate/initialize the bmap lock
222 	 */
223 	BMAP_LOCK_INIT(bmp);
224 
225 	return (0);
226 
227 err_release_metapage:
228 	release_metapage(mp);
229 err_kfree_bmp:
230 	kfree(bmp);
231 	return err;
232 }
233 
234 
235 /*
236  * NAME:	dbUnmount()
237  *
238  * FUNCTION:	terminate the block allocation map in preparation for
239  *		file system unmount.
240  *
241  *		the in-core bmap descriptor is written to disk and
242  *		the memory for this descriptor is freed.
243  *
244  * PARAMETERS:
245  *	ipbmap	- pointer to in-core inode for the block map.
246  *
247  * RETURN VALUES:
248  *	0	- success
249  *	-EIO	- i/o error
250  */
dbUnmount(struct inode * ipbmap,int mounterror)251 int dbUnmount(struct inode *ipbmap, int mounterror)
252 {
253 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
254 
255 	if (!(mounterror || isReadOnly(ipbmap)))
256 		dbSync(ipbmap);
257 
258 	/*
259 	 * Invalidate the page cache buffers
260 	 */
261 	truncate_inode_pages(ipbmap->i_mapping, 0);
262 
263 	/* free the memory for the in-memory bmap. */
264 	kfree(bmp);
265 
266 	return (0);
267 }
268 
269 /*
270  *	dbSync()
271  */
dbSync(struct inode * ipbmap)272 int dbSync(struct inode *ipbmap)
273 {
274 	struct dbmap_disk *dbmp_le;
275 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
276 	struct metapage *mp;
277 	int i;
278 
279 	/*
280 	 * write bmap global control page
281 	 */
282 	/* get the buffer for the on-disk bmap descriptor. */
283 	mp = read_metapage(ipbmap,
284 			   BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
285 			   PSIZE, 0);
286 	if (mp == NULL) {
287 		jfs_err("dbSync: read_metapage failed!");
288 		return -EIO;
289 	}
290 	/* copy the in-memory version of the bmap to the on-disk version */
291 	dbmp_le = (struct dbmap_disk *) mp->data;
292 	dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
293 	dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
294 	dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
295 	dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
296 	dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
297 	dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
298 	dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
299 	dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
300 	dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
301 	dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
302 	dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
303 	dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
304 	for (i = 0; i < MAXAG; i++)
305 		dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
306 	dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
307 	dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
308 
309 	/* write the buffer */
310 	write_metapage(mp);
311 
312 	/*
313 	 * write out dirty pages of bmap
314 	 */
315 	filemap_write_and_wait(ipbmap->i_mapping);
316 
317 	diWriteSpecial(ipbmap, 0);
318 
319 	return (0);
320 }
321 
322 /*
323  * NAME:	dbFree()
324  *
325  * FUNCTION:	free the specified block range from the working block
326  *		allocation map.
327  *
328  *		the blocks will be free from the working map one dmap
329  *		at a time.
330  *
331  * PARAMETERS:
332  *	ip	- pointer to in-core inode;
333  *	blkno	- starting block number to be freed.
334  *	nblocks	- number of blocks to be freed.
335  *
336  * RETURN VALUES:
337  *	0	- success
338  *	-EIO	- i/o error
339  */
dbFree(struct inode * ip,s64 blkno,s64 nblocks)340 int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
341 {
342 	struct metapage *mp;
343 	struct dmap *dp;
344 	int nb, rc;
345 	s64 lblkno, rem;
346 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
347 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
348 	struct super_block *sb = ipbmap->i_sb;
349 
350 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
351 
352 	/* block to be freed better be within the mapsize. */
353 	if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
354 		IREAD_UNLOCK(ipbmap);
355 		printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
356 		       (unsigned long long) blkno,
357 		       (unsigned long long) nblocks);
358 		jfs_error(ip->i_sb, "block to be freed is outside the map\n");
359 		return -EIO;
360 	}
361 
362 	/**
363 	 * TRIM the blocks, when mounted with discard option
364 	 */
365 	if (JFS_SBI(sb)->flag & JFS_DISCARD)
366 		if (JFS_SBI(sb)->minblks_trim <= nblocks)
367 			jfs_issue_discard(ipbmap, blkno, nblocks);
368 
369 	/*
370 	 * free the blocks a dmap at a time.
371 	 */
372 	mp = NULL;
373 	for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
374 		/* release previous dmap if any */
375 		if (mp) {
376 			write_metapage(mp);
377 		}
378 
379 		/* get the buffer for the current dmap. */
380 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
381 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
382 		if (mp == NULL) {
383 			IREAD_UNLOCK(ipbmap);
384 			return -EIO;
385 		}
386 		dp = (struct dmap *) mp->data;
387 
388 		/* determine the number of blocks to be freed from
389 		 * this dmap.
390 		 */
391 		nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
392 
393 		/* free the blocks. */
394 		if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
395 			jfs_error(ip->i_sb, "error in block map\n");
396 			release_metapage(mp);
397 			IREAD_UNLOCK(ipbmap);
398 			return (rc);
399 		}
400 	}
401 
402 	/* write the last buffer. */
403 	if (mp)
404 		write_metapage(mp);
405 
406 	IREAD_UNLOCK(ipbmap);
407 
408 	return (0);
409 }
410 
411 
412 /*
413  * NAME:	dbUpdatePMap()
414  *
415  * FUNCTION:	update the allocation state (free or allocate) of the
416  *		specified block range in the persistent block allocation map.
417  *
418  *		the blocks will be updated in the persistent map one
419  *		dmap at a time.
420  *
421  * PARAMETERS:
422  *	ipbmap	- pointer to in-core inode for the block map.
423  *	free	- 'true' if block range is to be freed from the persistent
424  *		  map; 'false' if it is to be allocated.
425  *	blkno	- starting block number of the range.
426  *	nblocks	- number of contiguous blocks in the range.
427  *	tblk	- transaction block;
428  *
429  * RETURN VALUES:
430  *	0	- success
431  *	-EIO	- i/o error
432  */
433 int
dbUpdatePMap(struct inode * ipbmap,int free,s64 blkno,s64 nblocks,struct tblock * tblk)434 dbUpdatePMap(struct inode *ipbmap,
435 	     int free, s64 blkno, s64 nblocks, struct tblock * tblk)
436 {
437 	int nblks, dbitno, wbitno, rbits;
438 	int word, nbits, nwords;
439 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
440 	s64 lblkno, rem, lastlblkno;
441 	u32 mask;
442 	struct dmap *dp;
443 	struct metapage *mp;
444 	struct jfs_log *log;
445 	int lsn, difft, diffp;
446 	unsigned long flags;
447 
448 	/* the blocks better be within the mapsize. */
449 	if (blkno + nblocks > bmp->db_mapsize) {
450 		printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
451 		       (unsigned long long) blkno,
452 		       (unsigned long long) nblocks);
453 		jfs_error(ipbmap->i_sb, "blocks are outside the map\n");
454 		return -EIO;
455 	}
456 
457 	/* compute delta of transaction lsn from log syncpt */
458 	lsn = tblk->lsn;
459 	log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
460 	logdiff(difft, lsn, log);
461 
462 	/*
463 	 * update the block state a dmap at a time.
464 	 */
465 	mp = NULL;
466 	lastlblkno = 0;
467 	for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
468 		/* get the buffer for the current dmap. */
469 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
470 		if (lblkno != lastlblkno) {
471 			if (mp) {
472 				write_metapage(mp);
473 			}
474 
475 			mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
476 					   0);
477 			if (mp == NULL)
478 				return -EIO;
479 			metapage_wait_for_io(mp);
480 		}
481 		dp = (struct dmap *) mp->data;
482 
483 		/* determine the bit number and word within the dmap of
484 		 * the starting block.  also determine how many blocks
485 		 * are to be updated within this dmap.
486 		 */
487 		dbitno = blkno & (BPERDMAP - 1);
488 		word = dbitno >> L2DBWORD;
489 		nblks = min(rem, (s64)BPERDMAP - dbitno);
490 
491 		/* update the bits of the dmap words. the first and last
492 		 * words may only have a subset of their bits updated. if
493 		 * this is the case, we'll work against that word (i.e.
494 		 * partial first and/or last) only in a single pass.  a
495 		 * single pass will also be used to update all words that
496 		 * are to have all their bits updated.
497 		 */
498 		for (rbits = nblks; rbits > 0;
499 		     rbits -= nbits, dbitno += nbits) {
500 			/* determine the bit number within the word and
501 			 * the number of bits within the word.
502 			 */
503 			wbitno = dbitno & (DBWORD - 1);
504 			nbits = min(rbits, DBWORD - wbitno);
505 
506 			/* check if only part of the word is to be updated. */
507 			if (nbits < DBWORD) {
508 				/* update (free or allocate) the bits
509 				 * in this word.
510 				 */
511 				mask =
512 				    (ONES << (DBWORD - nbits) >> wbitno);
513 				if (free)
514 					dp->pmap[word] &=
515 					    cpu_to_le32(~mask);
516 				else
517 					dp->pmap[word] |=
518 					    cpu_to_le32(mask);
519 
520 				word += 1;
521 			} else {
522 				/* one or more words are to have all
523 				 * their bits updated.  determine how
524 				 * many words and how many bits.
525 				 */
526 				nwords = rbits >> L2DBWORD;
527 				nbits = nwords << L2DBWORD;
528 
529 				/* update (free or allocate) the bits
530 				 * in these words.
531 				 */
532 				if (free)
533 					memset(&dp->pmap[word], 0,
534 					       nwords * 4);
535 				else
536 					memset(&dp->pmap[word], (int) ONES,
537 					       nwords * 4);
538 
539 				word += nwords;
540 			}
541 		}
542 
543 		/*
544 		 * update dmap lsn
545 		 */
546 		if (lblkno == lastlblkno)
547 			continue;
548 
549 		lastlblkno = lblkno;
550 
551 		LOGSYNC_LOCK(log, flags);
552 		if (mp->lsn != 0) {
553 			/* inherit older/smaller lsn */
554 			logdiff(diffp, mp->lsn, log);
555 			if (difft < diffp) {
556 				mp->lsn = lsn;
557 
558 				/* move bp after tblock in logsync list */
559 				list_move(&mp->synclist, &tblk->synclist);
560 			}
561 
562 			/* inherit younger/larger clsn */
563 			logdiff(difft, tblk->clsn, log);
564 			logdiff(diffp, mp->clsn, log);
565 			if (difft > diffp)
566 				mp->clsn = tblk->clsn;
567 		} else {
568 			mp->log = log;
569 			mp->lsn = lsn;
570 
571 			/* insert bp after tblock in logsync list */
572 			log->count++;
573 			list_add(&mp->synclist, &tblk->synclist);
574 
575 			mp->clsn = tblk->clsn;
576 		}
577 		LOGSYNC_UNLOCK(log, flags);
578 	}
579 
580 	/* write the last buffer. */
581 	if (mp) {
582 		write_metapage(mp);
583 	}
584 
585 	return (0);
586 }
587 
588 
589 /*
590  * NAME:	dbNextAG()
591  *
592  * FUNCTION:	find the preferred allocation group for new allocations.
593  *
594  *		Within the allocation groups, we maintain a preferred
595  *		allocation group which consists of a group with at least
596  *		average free space.  It is the preferred group that we target
597  *		new inode allocation towards.  The tie-in between inode
598  *		allocation and block allocation occurs as we allocate the
599  *		first (data) block of an inode and specify the inode (block)
600  *		as the allocation hint for this block.
601  *
602  *		We try to avoid having more than one open file growing in
603  *		an allocation group, as this will lead to fragmentation.
604  *		This differs from the old OS/2 method of trying to keep
605  *		empty ags around for large allocations.
606  *
607  * PARAMETERS:
608  *	ipbmap	- pointer to in-core inode for the block map.
609  *
610  * RETURN VALUES:
611  *	the preferred allocation group number.
612  */
dbNextAG(struct inode * ipbmap)613 int dbNextAG(struct inode *ipbmap)
614 {
615 	s64 avgfree;
616 	int agpref;
617 	s64 hwm = 0;
618 	int i;
619 	int next_best = -1;
620 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
621 
622 	BMAP_LOCK(bmp);
623 
624 	/* determine the average number of free blocks within the ags. */
625 	avgfree = (u32)bmp->db_nfree / bmp->db_numag;
626 
627 	/*
628 	 * if the current preferred ag does not have an active allocator
629 	 * and has at least average freespace, return it
630 	 */
631 	agpref = bmp->db_agpref;
632 	if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
633 	    (bmp->db_agfree[agpref] >= avgfree))
634 		goto unlock;
635 
636 	/* From the last preferred ag, find the next one with at least
637 	 * average free space.
638 	 */
639 	for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
640 		if (agpref == bmp->db_numag)
641 			agpref = 0;
642 
643 		if (atomic_read(&bmp->db_active[agpref]))
644 			/* open file is currently growing in this ag */
645 			continue;
646 		if (bmp->db_agfree[agpref] >= avgfree) {
647 			/* Return this one */
648 			bmp->db_agpref = agpref;
649 			goto unlock;
650 		} else if (bmp->db_agfree[agpref] > hwm) {
651 			/* Less than avg. freespace, but best so far */
652 			hwm = bmp->db_agfree[agpref];
653 			next_best = agpref;
654 		}
655 	}
656 
657 	/*
658 	 * If no inactive ag was found with average freespace, use the
659 	 * next best
660 	 */
661 	if (next_best != -1)
662 		bmp->db_agpref = next_best;
663 	/* else leave db_agpref unchanged */
664 unlock:
665 	BMAP_UNLOCK(bmp);
666 
667 	/* return the preferred group.
668 	 */
669 	return (bmp->db_agpref);
670 }
671 
672 /*
673  * NAME:	dbAlloc()
674  *
675  * FUNCTION:	attempt to allocate a specified number of contiguous free
676  *		blocks from the working allocation block map.
677  *
678  *		the block allocation policy uses hints and a multi-step
679  *		approach.
680  *
681  *		for allocation requests smaller than the number of blocks
682  *		per dmap, we first try to allocate the new blocks
683  *		immediately following the hint.  if these blocks are not
684  *		available, we try to allocate blocks near the hint.  if
685  *		no blocks near the hint are available, we next try to
686  *		allocate within the same dmap as contains the hint.
687  *
688  *		if no blocks are available in the dmap or the allocation
689  *		request is larger than the dmap size, we try to allocate
690  *		within the same allocation group as contains the hint. if
691  *		this does not succeed, we finally try to allocate anywhere
692  *		within the aggregate.
693  *
694  *		we also try to allocate anywhere within the aggregate
695  *		for allocation requests larger than the allocation group
696  *		size or requests that specify no hint value.
697  *
698  * PARAMETERS:
699  *	ip	- pointer to in-core inode;
700  *	hint	- allocation hint.
701  *	nblocks	- number of contiguous blocks in the range.
702  *	results	- on successful return, set to the starting block number
703  *		  of the newly allocated contiguous range.
704  *
705  * RETURN VALUES:
706  *	0	- success
707  *	-ENOSPC	- insufficient disk resources
708  *	-EIO	- i/o error
709  */
dbAlloc(struct inode * ip,s64 hint,s64 nblocks,s64 * results)710 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
711 {
712 	int rc, agno;
713 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
714 	struct bmap *bmp;
715 	struct metapage *mp;
716 	s64 lblkno, blkno;
717 	struct dmap *dp;
718 	int l2nb;
719 	s64 mapSize;
720 	int writers;
721 
722 	/* assert that nblocks is valid */
723 	assert(nblocks > 0);
724 
725 	/* get the log2 number of blocks to be allocated.
726 	 * if the number of blocks is not a log2 multiple,
727 	 * it will be rounded up to the next log2 multiple.
728 	 */
729 	l2nb = BLKSTOL2(nblocks);
730 
731 	bmp = JFS_SBI(ip->i_sb)->bmap;
732 
733 	mapSize = bmp->db_mapsize;
734 
735 	/* the hint should be within the map */
736 	if (hint >= mapSize) {
737 		jfs_error(ip->i_sb, "the hint is outside the map\n");
738 		return -EIO;
739 	}
740 
741 	/* if the number of blocks to be allocated is greater than the
742 	 * allocation group size, try to allocate anywhere.
743 	 */
744 	if (l2nb > bmp->db_agl2size) {
745 		IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
746 
747 		rc = dbAllocAny(bmp, nblocks, l2nb, results);
748 
749 		goto write_unlock;
750 	}
751 
752 	/*
753 	 * If no hint, let dbNextAG recommend an allocation group
754 	 */
755 	if (hint == 0)
756 		goto pref_ag;
757 
758 	/* we would like to allocate close to the hint.  adjust the
759 	 * hint to the block following the hint since the allocators
760 	 * will start looking for free space starting at this point.
761 	 */
762 	blkno = hint + 1;
763 
764 	if (blkno >= bmp->db_mapsize)
765 		goto pref_ag;
766 
767 	agno = blkno >> bmp->db_agl2size;
768 
769 	/* check if blkno crosses over into a new allocation group.
770 	 * if so, check if we should allow allocations within this
771 	 * allocation group.
772 	 */
773 	if ((blkno & (bmp->db_agsize - 1)) == 0)
774 		/* check if the AG is currently being written to.
775 		 * if so, call dbNextAG() to find a non-busy
776 		 * AG with sufficient free space.
777 		 */
778 		if (atomic_read(&bmp->db_active[agno]))
779 			goto pref_ag;
780 
781 	/* check if the allocation request size can be satisfied from a
782 	 * single dmap.  if so, try to allocate from the dmap containing
783 	 * the hint using a tiered strategy.
784 	 */
785 	if (nblocks <= BPERDMAP) {
786 		IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
787 
788 		/* get the buffer for the dmap containing the hint.
789 		 */
790 		rc = -EIO;
791 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
792 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
793 		if (mp == NULL)
794 			goto read_unlock;
795 
796 		dp = (struct dmap *) mp->data;
797 
798 		/* first, try to satisfy the allocation request with the
799 		 * blocks beginning at the hint.
800 		 */
801 		if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
802 		    != -ENOSPC) {
803 			if (rc == 0) {
804 				*results = blkno;
805 				mark_metapage_dirty(mp);
806 			}
807 
808 			release_metapage(mp);
809 			goto read_unlock;
810 		}
811 
812 		writers = atomic_read(&bmp->db_active[agno]);
813 		if ((writers > 1) ||
814 		    ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
815 			/*
816 			 * Someone else is writing in this allocation
817 			 * group.  To avoid fragmenting, try another ag
818 			 */
819 			release_metapage(mp);
820 			IREAD_UNLOCK(ipbmap);
821 			goto pref_ag;
822 		}
823 
824 		/* next, try to satisfy the allocation request with blocks
825 		 * near the hint.
826 		 */
827 		if ((rc =
828 		     dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
829 		    != -ENOSPC) {
830 			if (rc == 0)
831 				mark_metapage_dirty(mp);
832 
833 			release_metapage(mp);
834 			goto read_unlock;
835 		}
836 
837 		/* try to satisfy the allocation request with blocks within
838 		 * the same dmap as the hint.
839 		 */
840 		if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
841 		    != -ENOSPC) {
842 			if (rc == 0)
843 				mark_metapage_dirty(mp);
844 
845 			release_metapage(mp);
846 			goto read_unlock;
847 		}
848 
849 		release_metapage(mp);
850 		IREAD_UNLOCK(ipbmap);
851 	}
852 
853 	/* try to satisfy the allocation request with blocks within
854 	 * the same allocation group as the hint.
855 	 */
856 	IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
857 	if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
858 		goto write_unlock;
859 
860 	IWRITE_UNLOCK(ipbmap);
861 
862 
863       pref_ag:
864 	/*
865 	 * Let dbNextAG recommend a preferred allocation group
866 	 */
867 	agno = dbNextAG(ipbmap);
868 	IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
869 
870 	/* Try to allocate within this allocation group.  if that fails, try to
871 	 * allocate anywhere in the map.
872 	 */
873 	if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
874 		rc = dbAllocAny(bmp, nblocks, l2nb, results);
875 
876       write_unlock:
877 	IWRITE_UNLOCK(ipbmap);
878 
879 	return (rc);
880 
881       read_unlock:
882 	IREAD_UNLOCK(ipbmap);
883 
884 	return (rc);
885 }
886 
887 /*
888  * NAME:	dbReAlloc()
889  *
890  * FUNCTION:	attempt to extend a current allocation by a specified
891  *		number of blocks.
892  *
893  *		this routine attempts to satisfy the allocation request
894  *		by first trying to extend the existing allocation in
895  *		place by allocating the additional blocks as the blocks
896  *		immediately following the current allocation.  if these
897  *		blocks are not available, this routine will attempt to
898  *		allocate a new set of contiguous blocks large enough
899  *		to cover the existing allocation plus the additional
900  *		number of blocks required.
901  *
902  * PARAMETERS:
903  *	ip	    -  pointer to in-core inode requiring allocation.
904  *	blkno	    -  starting block of the current allocation.
905  *	nblocks	    -  number of contiguous blocks within the current
906  *		       allocation.
907  *	addnblocks  -  number of blocks to add to the allocation.
908  *	results	-      on successful return, set to the starting block number
909  *		       of the existing allocation if the existing allocation
910  *		       was extended in place or to a newly allocated contiguous
911  *		       range if the existing allocation could not be extended
912  *		       in place.
913  *
914  * RETURN VALUES:
915  *	0	- success
916  *	-ENOSPC	- insufficient disk resources
917  *	-EIO	- i/o error
918  */
919 int
dbReAlloc(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks,s64 * results)920 dbReAlloc(struct inode *ip,
921 	  s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
922 {
923 	int rc;
924 
925 	/* try to extend the allocation in place.
926 	 */
927 	if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
928 		*results = blkno;
929 		return (0);
930 	} else {
931 		if (rc != -ENOSPC)
932 			return (rc);
933 	}
934 
935 	/* could not extend the allocation in place, so allocate a
936 	 * new set of blocks for the entire request (i.e. try to get
937 	 * a range of contiguous blocks large enough to cover the
938 	 * existing allocation plus the additional blocks.)
939 	 */
940 	return (dbAlloc
941 		(ip, blkno + nblocks - 1, addnblocks + nblocks, results));
942 }
943 
944 
945 /*
946  * NAME:	dbExtend()
947  *
948  * FUNCTION:	attempt to extend a current allocation by a specified
949  *		number of blocks.
950  *
951  *		this routine attempts to satisfy the allocation request
952  *		by first trying to extend the existing allocation in
953  *		place by allocating the additional blocks as the blocks
954  *		immediately following the current allocation.
955  *
956  * PARAMETERS:
957  *	ip	    -  pointer to in-core inode requiring allocation.
958  *	blkno	    -  starting block of the current allocation.
959  *	nblocks	    -  number of contiguous blocks within the current
960  *		       allocation.
961  *	addnblocks  -  number of blocks to add to the allocation.
962  *
963  * RETURN VALUES:
964  *	0	- success
965  *	-ENOSPC	- insufficient disk resources
966  *	-EIO	- i/o error
967  */
dbExtend(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks)968 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
969 {
970 	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
971 	s64 lblkno, lastblkno, extblkno;
972 	uint rel_block;
973 	struct metapage *mp;
974 	struct dmap *dp;
975 	int rc;
976 	struct inode *ipbmap = sbi->ipbmap;
977 	struct bmap *bmp;
978 
979 	/*
980 	 * We don't want a non-aligned extent to cross a page boundary
981 	 */
982 	if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
983 	    (rel_block + nblocks + addnblocks > sbi->nbperpage))
984 		return -ENOSPC;
985 
986 	/* get the last block of the current allocation */
987 	lastblkno = blkno + nblocks - 1;
988 
989 	/* determine the block number of the block following
990 	 * the existing allocation.
991 	 */
992 	extblkno = lastblkno + 1;
993 
994 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
995 
996 	/* better be within the file system */
997 	bmp = sbi->bmap;
998 	if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
999 		IREAD_UNLOCK(ipbmap);
1000 		jfs_error(ip->i_sb, "the block is outside the filesystem\n");
1001 		return -EIO;
1002 	}
1003 
1004 	/* we'll attempt to extend the current allocation in place by
1005 	 * allocating the additional blocks as the blocks immediately
1006 	 * following the current allocation.  we only try to extend the
1007 	 * current allocation in place if the number of additional blocks
1008 	 * can fit into a dmap, the last block of the current allocation
1009 	 * is not the last block of the file system, and the start of the
1010 	 * inplace extension is not on an allocation group boundary.
1011 	 */
1012 	if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1013 	    (extblkno & (bmp->db_agsize - 1)) == 0) {
1014 		IREAD_UNLOCK(ipbmap);
1015 		return -ENOSPC;
1016 	}
1017 
1018 	/* get the buffer for the dmap containing the first block
1019 	 * of the extension.
1020 	 */
1021 	lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1022 	mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1023 	if (mp == NULL) {
1024 		IREAD_UNLOCK(ipbmap);
1025 		return -EIO;
1026 	}
1027 
1028 	dp = (struct dmap *) mp->data;
1029 
1030 	/* try to allocate the blocks immediately following the
1031 	 * current allocation.
1032 	 */
1033 	rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1034 
1035 	IREAD_UNLOCK(ipbmap);
1036 
1037 	/* were we successful ? */
1038 	if (rc == 0)
1039 		write_metapage(mp);
1040 	else
1041 		/* we were not successful */
1042 		release_metapage(mp);
1043 
1044 	return (rc);
1045 }
1046 
1047 
1048 /*
1049  * NAME:	dbAllocNext()
1050  *
1051  * FUNCTION:	attempt to allocate the blocks of the specified block
1052  *		range within a dmap.
1053  *
1054  * PARAMETERS:
1055  *	bmp	-  pointer to bmap descriptor
1056  *	dp	-  pointer to dmap.
1057  *	blkno	-  starting block number of the range.
1058  *	nblocks	-  number of contiguous free blocks of the range.
1059  *
1060  * RETURN VALUES:
1061  *	0	- success
1062  *	-ENOSPC	- insufficient disk resources
1063  *	-EIO	- i/o error
1064  *
1065  * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1066  */
dbAllocNext(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)1067 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1068 		       int nblocks)
1069 {
1070 	int dbitno, word, rembits, nb, nwords, wbitno, nw;
1071 	int l2size;
1072 	s8 *leaf;
1073 	u32 mask;
1074 
1075 	if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1076 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1077 		return -EIO;
1078 	}
1079 
1080 	/* pick up a pointer to the leaves of the dmap tree.
1081 	 */
1082 	leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1083 
1084 	/* determine the bit number and word within the dmap of the
1085 	 * starting block.
1086 	 */
1087 	dbitno = blkno & (BPERDMAP - 1);
1088 	word = dbitno >> L2DBWORD;
1089 
1090 	/* check if the specified block range is contained within
1091 	 * this dmap.
1092 	 */
1093 	if (dbitno + nblocks > BPERDMAP)
1094 		return -ENOSPC;
1095 
1096 	/* check if the starting leaf indicates that anything
1097 	 * is free.
1098 	 */
1099 	if (leaf[word] == NOFREE)
1100 		return -ENOSPC;
1101 
1102 	/* check the dmaps words corresponding to block range to see
1103 	 * if the block range is free.  not all bits of the first and
1104 	 * last words may be contained within the block range.  if this
1105 	 * is the case, we'll work against those words (i.e. partial first
1106 	 * and/or last) on an individual basis (a single pass) and examine
1107 	 * the actual bits to determine if they are free.  a single pass
1108 	 * will be used for all dmap words fully contained within the
1109 	 * specified range.  within this pass, the leaves of the dmap
1110 	 * tree will be examined to determine if the blocks are free. a
1111 	 * single leaf may describe the free space of multiple dmap
1112 	 * words, so we may visit only a subset of the actual leaves
1113 	 * corresponding to the dmap words of the block range.
1114 	 */
1115 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1116 		/* determine the bit number within the word and
1117 		 * the number of bits within the word.
1118 		 */
1119 		wbitno = dbitno & (DBWORD - 1);
1120 		nb = min(rembits, DBWORD - wbitno);
1121 
1122 		/* check if only part of the word is to be examined.
1123 		 */
1124 		if (nb < DBWORD) {
1125 			/* check if the bits are free.
1126 			 */
1127 			mask = (ONES << (DBWORD - nb) >> wbitno);
1128 			if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1129 				return -ENOSPC;
1130 
1131 			word += 1;
1132 		} else {
1133 			/* one or more dmap words are fully contained
1134 			 * within the block range.  determine how many
1135 			 * words and how many bits.
1136 			 */
1137 			nwords = rembits >> L2DBWORD;
1138 			nb = nwords << L2DBWORD;
1139 
1140 			/* now examine the appropriate leaves to determine
1141 			 * if the blocks are free.
1142 			 */
1143 			while (nwords > 0) {
1144 				/* does the leaf describe any free space ?
1145 				 */
1146 				if (leaf[word] < BUDMIN)
1147 					return -ENOSPC;
1148 
1149 				/* determine the l2 number of bits provided
1150 				 * by this leaf.
1151 				 */
1152 				l2size =
1153 				    min_t(int, leaf[word], NLSTOL2BSZ(nwords));
1154 
1155 				/* determine how many words were handled.
1156 				 */
1157 				nw = BUDSIZE(l2size, BUDMIN);
1158 
1159 				nwords -= nw;
1160 				word += nw;
1161 			}
1162 		}
1163 	}
1164 
1165 	/* allocate the blocks.
1166 	 */
1167 	return (dbAllocDmap(bmp, dp, blkno, nblocks));
1168 }
1169 
1170 
1171 /*
1172  * NAME:	dbAllocNear()
1173  *
1174  * FUNCTION:	attempt to allocate a number of contiguous free blocks near
1175  *		a specified block (hint) within a dmap.
1176  *
1177  *		starting with the dmap leaf that covers the hint, we'll
1178  *		check the next four contiguous leaves for sufficient free
1179  *		space.  if sufficient free space is found, we'll allocate
1180  *		the desired free space.
1181  *
1182  * PARAMETERS:
1183  *	bmp	-  pointer to bmap descriptor
1184  *	dp	-  pointer to dmap.
1185  *	blkno	-  block number to allocate near.
1186  *	nblocks	-  actual number of contiguous free blocks desired.
1187  *	l2nb	-  log2 number of contiguous free blocks desired.
1188  *	results	-  on successful return, set to the starting block number
1189  *		   of the newly allocated range.
1190  *
1191  * RETURN VALUES:
1192  *	0	- success
1193  *	-ENOSPC	- insufficient disk resources
1194  *	-EIO	- i/o error
1195  *
1196  * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1197  */
1198 static int
dbAllocNear(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks,int l2nb,s64 * results)1199 dbAllocNear(struct bmap * bmp,
1200 	    struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1201 {
1202 	int word, lword, rc;
1203 	s8 *leaf;
1204 
1205 	if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1206 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1207 		return -EIO;
1208 	}
1209 
1210 	leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1211 
1212 	/* determine the word within the dmap that holds the hint
1213 	 * (i.e. blkno).  also, determine the last word in the dmap
1214 	 * that we'll include in our examination.
1215 	 */
1216 	word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1217 	lword = min(word + 4, LPERDMAP);
1218 
1219 	/* examine the leaves for sufficient free space.
1220 	 */
1221 	for (; word < lword; word++) {
1222 		/* does the leaf describe sufficient free space ?
1223 		 */
1224 		if (leaf[word] < l2nb)
1225 			continue;
1226 
1227 		/* determine the block number within the file system
1228 		 * of the first block described by this dmap word.
1229 		 */
1230 		blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1231 
1232 		/* if not all bits of the dmap word are free, get the
1233 		 * starting bit number within the dmap word of the required
1234 		 * string of free bits and adjust the block number with the
1235 		 * value.
1236 		 */
1237 		if (leaf[word] < BUDMIN)
1238 			blkno +=
1239 			    dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1240 
1241 		/* allocate the blocks.
1242 		 */
1243 		if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1244 			*results = blkno;
1245 
1246 		return (rc);
1247 	}
1248 
1249 	return -ENOSPC;
1250 }
1251 
1252 
1253 /*
1254  * NAME:	dbAllocAG()
1255  *
1256  * FUNCTION:	attempt to allocate the specified number of contiguous
1257  *		free blocks within the specified allocation group.
1258  *
1259  *		unless the allocation group size is equal to the number
1260  *		of blocks per dmap, the dmap control pages will be used to
1261  *		find the required free space, if available.  we start the
1262  *		search at the highest dmap control page level which
1263  *		distinctly describes the allocation group's free space
1264  *		(i.e. the highest level at which the allocation group's
1265  *		free space is not mixed in with that of any other group).
1266  *		in addition, we start the search within this level at a
1267  *		height of the dmapctl dmtree at which the nodes distinctly
1268  *		describe the allocation group's free space.  at this height,
1269  *		the allocation group's free space may be represented by 1
1270  *		or two sub-trees, depending on the allocation group size.
1271  *		we search the top nodes of these subtrees left to right for
1272  *		sufficient free space.  if sufficient free space is found,
1273  *		the subtree is searched to find the leftmost leaf that
1274  *		has free space.  once we have made it to the leaf, we
1275  *		move the search to the next lower level dmap control page
1276  *		corresponding to this leaf.  we continue down the dmap control
1277  *		pages until we find the dmap that contains or starts the
1278  *		sufficient free space and we allocate at this dmap.
1279  *
1280  *		if the allocation group size is equal to the dmap size,
1281  *		we'll start at the dmap corresponding to the allocation
1282  *		group and attempt the allocation at this level.
1283  *
1284  *		the dmap control page search is also not performed if the
1285  *		allocation group is completely free and we go to the first
1286  *		dmap of the allocation group to do the allocation.  this is
1287  *		done because the allocation group may be part (not the first
1288  *		part) of a larger binary buddy system, causing the dmap
1289  *		control pages to indicate no free space (NOFREE) within
1290  *		the allocation group.
1291  *
1292  * PARAMETERS:
1293  *	bmp	-  pointer to bmap descriptor
1294  *	agno	- allocation group number.
1295  *	nblocks	-  actual number of contiguous free blocks desired.
1296  *	l2nb	-  log2 number of contiguous free blocks desired.
1297  *	results	-  on successful return, set to the starting block number
1298  *		   of the newly allocated range.
1299  *
1300  * RETURN VALUES:
1301  *	0	- success
1302  *	-ENOSPC	- insufficient disk resources
1303  *	-EIO	- i/o error
1304  *
1305  * note: IWRITE_LOCK(ipmap) held on entry/exit;
1306  */
1307 static int
dbAllocAG(struct bmap * bmp,int agno,s64 nblocks,int l2nb,s64 * results)1308 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1309 {
1310 	struct metapage *mp;
1311 	struct dmapctl *dcp;
1312 	int rc, ti, i, k, m, n, agperlev;
1313 	s64 blkno, lblkno;
1314 	int budmin;
1315 
1316 	/* allocation request should not be for more than the
1317 	 * allocation group size.
1318 	 */
1319 	if (l2nb > bmp->db_agl2size) {
1320 		jfs_error(bmp->db_ipbmap->i_sb,
1321 			  "allocation request is larger than the allocation group size\n");
1322 		return -EIO;
1323 	}
1324 
1325 	/* determine the starting block number of the allocation
1326 	 * group.
1327 	 */
1328 	blkno = (s64) agno << bmp->db_agl2size;
1329 
1330 	/* check if the allocation group size is the minimum allocation
1331 	 * group size or if the allocation group is completely free. if
1332 	 * the allocation group size is the minimum size of BPERDMAP (i.e.
1333 	 * 1 dmap), there is no need to search the dmap control page (below)
1334 	 * that fully describes the allocation group since the allocation
1335 	 * group is already fully described by a dmap.  in this case, we
1336 	 * just call dbAllocCtl() to search the dmap tree and allocate the
1337 	 * required space if available.
1338 	 *
1339 	 * if the allocation group is completely free, dbAllocCtl() is
1340 	 * also called to allocate the required space.  this is done for
1341 	 * two reasons.  first, it makes no sense searching the dmap control
1342 	 * pages for free space when we know that free space exists.  second,
1343 	 * the dmap control pages may indicate that the allocation group
1344 	 * has no free space if the allocation group is part (not the first
1345 	 * part) of a larger binary buddy system.
1346 	 */
1347 	if (bmp->db_agsize == BPERDMAP
1348 	    || bmp->db_agfree[agno] == bmp->db_agsize) {
1349 		rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1350 		if ((rc == -ENOSPC) &&
1351 		    (bmp->db_agfree[agno] == bmp->db_agsize)) {
1352 			printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1353 			       (unsigned long long) blkno,
1354 			       (unsigned long long) nblocks);
1355 			jfs_error(bmp->db_ipbmap->i_sb,
1356 				  "dbAllocCtl failed in free AG\n");
1357 		}
1358 		return (rc);
1359 	}
1360 
1361 	/* the buffer for the dmap control page that fully describes the
1362 	 * allocation group.
1363 	 */
1364 	lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1365 	mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1366 	if (mp == NULL)
1367 		return -EIO;
1368 	dcp = (struct dmapctl *) mp->data;
1369 	budmin = dcp->budmin;
1370 
1371 	if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1372 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
1373 		release_metapage(mp);
1374 		return -EIO;
1375 	}
1376 
1377 	/* search the subtree(s) of the dmap control page that describes
1378 	 * the allocation group, looking for sufficient free space.  to begin,
1379 	 * determine how many allocation groups are represented in a dmap
1380 	 * control page at the control page level (i.e. L0, L1, L2) that
1381 	 * fully describes an allocation group. next, determine the starting
1382 	 * tree index of this allocation group within the control page.
1383 	 */
1384 	agperlev =
1385 	    (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1386 	ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1387 
1388 	/* dmap control page trees fan-out by 4 and a single allocation
1389 	 * group may be described by 1 or 2 subtrees within the ag level
1390 	 * dmap control page, depending upon the ag size. examine the ag's
1391 	 * subtrees for sufficient free space, starting with the leftmost
1392 	 * subtree.
1393 	 */
1394 	for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1395 		/* is there sufficient free space ?
1396 		 */
1397 		if (l2nb > dcp->stree[ti])
1398 			continue;
1399 
1400 		/* sufficient free space found in a subtree. now search down
1401 		 * the subtree to find the leftmost leaf that describes this
1402 		 * free space.
1403 		 */
1404 		for (k = bmp->db_agheight; k > 0; k--) {
1405 			for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1406 				if (l2nb <= dcp->stree[m + n]) {
1407 					ti = m + n;
1408 					break;
1409 				}
1410 			}
1411 			if (n == 4) {
1412 				jfs_error(bmp->db_ipbmap->i_sb,
1413 					  "failed descending stree\n");
1414 				release_metapage(mp);
1415 				return -EIO;
1416 			}
1417 		}
1418 
1419 		/* determine the block number within the file system
1420 		 * that corresponds to this leaf.
1421 		 */
1422 		if (bmp->db_aglevel == 2)
1423 			blkno = 0;
1424 		else if (bmp->db_aglevel == 1)
1425 			blkno &= ~(MAXL1SIZE - 1);
1426 		else		/* bmp->db_aglevel == 0 */
1427 			blkno &= ~(MAXL0SIZE - 1);
1428 
1429 		blkno +=
1430 		    ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1431 
1432 		/* release the buffer in preparation for going down
1433 		 * the next level of dmap control pages.
1434 		 */
1435 		release_metapage(mp);
1436 
1437 		/* check if we need to continue to search down the lower
1438 		 * level dmap control pages.  we need to if the number of
1439 		 * blocks required is less than maximum number of blocks
1440 		 * described at the next lower level.
1441 		 */
1442 		if (l2nb < budmin) {
1443 
1444 			/* search the lower level dmap control pages to get
1445 			 * the starting block number of the dmap that
1446 			 * contains or starts off the free space.
1447 			 */
1448 			if ((rc =
1449 			     dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1450 				       &blkno))) {
1451 				if (rc == -ENOSPC) {
1452 					jfs_error(bmp->db_ipbmap->i_sb,
1453 						  "control page inconsistent\n");
1454 					return -EIO;
1455 				}
1456 				return (rc);
1457 			}
1458 		}
1459 
1460 		/* allocate the blocks.
1461 		 */
1462 		rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1463 		if (rc == -ENOSPC) {
1464 			jfs_error(bmp->db_ipbmap->i_sb,
1465 				  "unable to allocate blocks\n");
1466 			rc = -EIO;
1467 		}
1468 		return (rc);
1469 	}
1470 
1471 	/* no space in the allocation group.  release the buffer and
1472 	 * return -ENOSPC.
1473 	 */
1474 	release_metapage(mp);
1475 
1476 	return -ENOSPC;
1477 }
1478 
1479 
1480 /*
1481  * NAME:	dbAllocAny()
1482  *
1483  * FUNCTION:	attempt to allocate the specified number of contiguous
1484  *		free blocks anywhere in the file system.
1485  *
1486  *		dbAllocAny() attempts to find the sufficient free space by
1487  *		searching down the dmap control pages, starting with the
1488  *		highest level (i.e. L0, L1, L2) control page.  if free space
1489  *		large enough to satisfy the desired free space is found, the
1490  *		desired free space is allocated.
1491  *
1492  * PARAMETERS:
1493  *	bmp	-  pointer to bmap descriptor
1494  *	nblocks	 -  actual number of contiguous free blocks desired.
1495  *	l2nb	 -  log2 number of contiguous free blocks desired.
1496  *	results	-  on successful return, set to the starting block number
1497  *		   of the newly allocated range.
1498  *
1499  * RETURN VALUES:
1500  *	0	- success
1501  *	-ENOSPC	- insufficient disk resources
1502  *	-EIO	- i/o error
1503  *
1504  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1505  */
dbAllocAny(struct bmap * bmp,s64 nblocks,int l2nb,s64 * results)1506 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1507 {
1508 	int rc;
1509 	s64 blkno = 0;
1510 
1511 	/* starting with the top level dmap control page, search
1512 	 * down the dmap control levels for sufficient free space.
1513 	 * if free space is found, dbFindCtl() returns the starting
1514 	 * block number of the dmap that contains or starts off the
1515 	 * range of free space.
1516 	 */
1517 	if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1518 		return (rc);
1519 
1520 	/* allocate the blocks.
1521 	 */
1522 	rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1523 	if (rc == -ENOSPC) {
1524 		jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n");
1525 		return -EIO;
1526 	}
1527 	return (rc);
1528 }
1529 
1530 
1531 /*
1532  * NAME:	dbDiscardAG()
1533  *
1534  * FUNCTION:	attempt to discard (TRIM) all free blocks of specific AG
1535  *
1536  *		algorithm:
1537  *		1) allocate blocks, as large as possible and save them
1538  *		   while holding IWRITE_LOCK on ipbmap
1539  *		2) trim all these saved block/length values
1540  *		3) mark the blocks free again
1541  *
1542  *		benefit:
1543  *		- we work only on one ag at some time, minimizing how long we
1544  *		  need to lock ipbmap
1545  *		- reading / writing the fs is possible most time, even on
1546  *		  trimming
1547  *
1548  *		downside:
1549  *		- we write two times to the dmapctl and dmap pages
1550  *		- but for me, this seems the best way, better ideas?
1551  *		/TR 2012
1552  *
1553  * PARAMETERS:
1554  *	ip	- pointer to in-core inode
1555  *	agno	- ag to trim
1556  *	minlen	- minimum value of contiguous blocks
1557  *
1558  * RETURN VALUES:
1559  *	s64	- actual number of blocks trimmed
1560  */
dbDiscardAG(struct inode * ip,int agno,s64 minlen)1561 s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
1562 {
1563 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
1564 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
1565 	s64 nblocks, blkno;
1566 	u64 trimmed = 0;
1567 	int rc, l2nb;
1568 	struct super_block *sb = ipbmap->i_sb;
1569 
1570 	struct range2trim {
1571 		u64 blkno;
1572 		u64 nblocks;
1573 	} *totrim, *tt;
1574 
1575 	/* max blkno / nblocks pairs to trim */
1576 	int count = 0, range_cnt;
1577 	u64 max_ranges;
1578 
1579 	/* prevent others from writing new stuff here, while trimming */
1580 	IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
1581 
1582 	nblocks = bmp->db_agfree[agno];
1583 	max_ranges = nblocks;
1584 	do_div(max_ranges, minlen);
1585 	range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
1586 	totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS);
1587 	if (totrim == NULL) {
1588 		jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n");
1589 		IWRITE_UNLOCK(ipbmap);
1590 		return 0;
1591 	}
1592 
1593 	tt = totrim;
1594 	while (nblocks >= minlen) {
1595 		l2nb = BLKSTOL2(nblocks);
1596 
1597 		/* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
1598 		rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
1599 		if (rc == 0) {
1600 			tt->blkno = blkno;
1601 			tt->nblocks = nblocks;
1602 			tt++; count++;
1603 
1604 			/* the whole ag is free, trim now */
1605 			if (bmp->db_agfree[agno] == 0)
1606 				break;
1607 
1608 			/* give a hint for the next while */
1609 			nblocks = bmp->db_agfree[agno];
1610 			continue;
1611 		} else if (rc == -ENOSPC) {
1612 			/* search for next smaller log2 block */
1613 			l2nb = BLKSTOL2(nblocks) - 1;
1614 			nblocks = 1LL << l2nb;
1615 		} else {
1616 			/* Trim any already allocated blocks */
1617 			jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
1618 			break;
1619 		}
1620 
1621 		/* check, if our trim array is full */
1622 		if (unlikely(count >= range_cnt - 1))
1623 			break;
1624 	}
1625 	IWRITE_UNLOCK(ipbmap);
1626 
1627 	tt->nblocks = 0; /* mark the current end */
1628 	for (tt = totrim; tt->nblocks != 0; tt++) {
1629 		/* when mounted with online discard, dbFree() will
1630 		 * call jfs_issue_discard() itself */
1631 		if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
1632 			jfs_issue_discard(ip, tt->blkno, tt->nblocks);
1633 		dbFree(ip, tt->blkno, tt->nblocks);
1634 		trimmed += tt->nblocks;
1635 	}
1636 	kfree(totrim);
1637 
1638 	return trimmed;
1639 }
1640 
1641 /*
1642  * NAME:	dbFindCtl()
1643  *
1644  * FUNCTION:	starting at a specified dmap control page level and block
1645  *		number, search down the dmap control levels for a range of
1646  *		contiguous free blocks large enough to satisfy an allocation
1647  *		request for the specified number of free blocks.
1648  *
1649  *		if sufficient contiguous free blocks are found, this routine
1650  *		returns the starting block number within a dmap page that
1651  *		contains or starts a range of contiqious free blocks that
1652  *		is sufficient in size.
1653  *
1654  * PARAMETERS:
1655  *	bmp	-  pointer to bmap descriptor
1656  *	level	-  starting dmap control page level.
1657  *	l2nb	-  log2 number of contiguous free blocks desired.
1658  *	*blkno	-  on entry, starting block number for conducting the search.
1659  *		   on successful return, the first block within a dmap page
1660  *		   that contains or starts a range of contiguous free blocks.
1661  *
1662  * RETURN VALUES:
1663  *	0	- success
1664  *	-ENOSPC	- insufficient disk resources
1665  *	-EIO	- i/o error
1666  *
1667  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1668  */
dbFindCtl(struct bmap * bmp,int l2nb,int level,s64 * blkno)1669 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1670 {
1671 	int rc, leafidx, lev;
1672 	s64 b, lblkno;
1673 	struct dmapctl *dcp;
1674 	int budmin;
1675 	struct metapage *mp;
1676 
1677 	/* starting at the specified dmap control page level and block
1678 	 * number, search down the dmap control levels for the starting
1679 	 * block number of a dmap page that contains or starts off
1680 	 * sufficient free blocks.
1681 	 */
1682 	for (lev = level, b = *blkno; lev >= 0; lev--) {
1683 		/* get the buffer of the dmap control page for the block
1684 		 * number and level (i.e. L0, L1, L2).
1685 		 */
1686 		lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1687 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1688 		if (mp == NULL)
1689 			return -EIO;
1690 		dcp = (struct dmapctl *) mp->data;
1691 		budmin = dcp->budmin;
1692 
1693 		if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1694 			jfs_error(bmp->db_ipbmap->i_sb,
1695 				  "Corrupt dmapctl page\n");
1696 			release_metapage(mp);
1697 			return -EIO;
1698 		}
1699 
1700 		/* search the tree within the dmap control page for
1701 		 * sufficient free space.  if sufficient free space is found,
1702 		 * dbFindLeaf() returns the index of the leaf at which
1703 		 * free space was found.
1704 		 */
1705 		rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1706 
1707 		/* release the buffer.
1708 		 */
1709 		release_metapage(mp);
1710 
1711 		/* space found ?
1712 		 */
1713 		if (rc) {
1714 			if (lev != level) {
1715 				jfs_error(bmp->db_ipbmap->i_sb,
1716 					  "dmap inconsistent\n");
1717 				return -EIO;
1718 			}
1719 			return -ENOSPC;
1720 		}
1721 
1722 		/* adjust the block number to reflect the location within
1723 		 * the dmap control page (i.e. the leaf) at which free
1724 		 * space was found.
1725 		 */
1726 		b += (((s64) leafidx) << budmin);
1727 
1728 		/* we stop the search at this dmap control page level if
1729 		 * the number of blocks required is greater than or equal
1730 		 * to the maximum number of blocks described at the next
1731 		 * (lower) level.
1732 		 */
1733 		if (l2nb >= budmin)
1734 			break;
1735 	}
1736 
1737 	*blkno = b;
1738 	return (0);
1739 }
1740 
1741 
1742 /*
1743  * NAME:	dbAllocCtl()
1744  *
1745  * FUNCTION:	attempt to allocate a specified number of contiguous
1746  *		blocks starting within a specific dmap.
1747  *
1748  *		this routine is called by higher level routines that search
1749  *		the dmap control pages above the actual dmaps for contiguous
1750  *		free space.  the result of successful searches by these
1751  *		routines are the starting block numbers within dmaps, with
1752  *		the dmaps themselves containing the desired contiguous free
1753  *		space or starting a contiguous free space of desired size
1754  *		that is made up of the blocks of one or more dmaps. these
1755  *		calls should not fail due to insufficent resources.
1756  *
1757  *		this routine is called in some cases where it is not known
1758  *		whether it will fail due to insufficient resources.  more
1759  *		specifically, this occurs when allocating from an allocation
1760  *		group whose size is equal to the number of blocks per dmap.
1761  *		in this case, the dmap control pages are not examined prior
1762  *		to calling this routine (to save pathlength) and the call
1763  *		might fail.
1764  *
1765  *		for a request size that fits within a dmap, this routine relies
1766  *		upon the dmap's dmtree to find the requested contiguous free
1767  *		space.  for request sizes that are larger than a dmap, the
1768  *		requested free space will start at the first block of the
1769  *		first dmap (i.e. blkno).
1770  *
1771  * PARAMETERS:
1772  *	bmp	-  pointer to bmap descriptor
1773  *	nblocks	 -  actual number of contiguous free blocks to allocate.
1774  *	l2nb	 -  log2 number of contiguous free blocks to allocate.
1775  *	blkno	 -  starting block number of the dmap to start the allocation
1776  *		    from.
1777  *	results	-  on successful return, set to the starting block number
1778  *		   of the newly allocated range.
1779  *
1780  * RETURN VALUES:
1781  *	0	- success
1782  *	-ENOSPC	- insufficient disk resources
1783  *	-EIO	- i/o error
1784  *
1785  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1786  */
1787 static int
dbAllocCtl(struct bmap * bmp,s64 nblocks,int l2nb,s64 blkno,s64 * results)1788 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1789 {
1790 	int rc, nb;
1791 	s64 b, lblkno, n;
1792 	struct metapage *mp;
1793 	struct dmap *dp;
1794 
1795 	/* check if the allocation request is confined to a single dmap.
1796 	 */
1797 	if (l2nb <= L2BPERDMAP) {
1798 		/* get the buffer for the dmap.
1799 		 */
1800 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1801 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1802 		if (mp == NULL)
1803 			return -EIO;
1804 		dp = (struct dmap *) mp->data;
1805 
1806 		/* try to allocate the blocks.
1807 		 */
1808 		rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1809 		if (rc == 0)
1810 			mark_metapage_dirty(mp);
1811 
1812 		release_metapage(mp);
1813 
1814 		return (rc);
1815 	}
1816 
1817 	/* allocation request involving multiple dmaps. it must start on
1818 	 * a dmap boundary.
1819 	 */
1820 	assert((blkno & (BPERDMAP - 1)) == 0);
1821 
1822 	/* allocate the blocks dmap by dmap.
1823 	 */
1824 	for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1825 		/* get the buffer for the dmap.
1826 		 */
1827 		lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1828 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1829 		if (mp == NULL) {
1830 			rc = -EIO;
1831 			goto backout;
1832 		}
1833 		dp = (struct dmap *) mp->data;
1834 
1835 		/* the dmap better be all free.
1836 		 */
1837 		if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1838 			release_metapage(mp);
1839 			jfs_error(bmp->db_ipbmap->i_sb,
1840 				  "the dmap is not all free\n");
1841 			rc = -EIO;
1842 			goto backout;
1843 		}
1844 
1845 		/* determine how many blocks to allocate from this dmap.
1846 		 */
1847 		nb = min_t(s64, n, BPERDMAP);
1848 
1849 		/* allocate the blocks from the dmap.
1850 		 */
1851 		if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1852 			release_metapage(mp);
1853 			goto backout;
1854 		}
1855 
1856 		/* write the buffer.
1857 		 */
1858 		write_metapage(mp);
1859 	}
1860 
1861 	/* set the results (starting block number) and return.
1862 	 */
1863 	*results = blkno;
1864 	return (0);
1865 
1866 	/* something failed in handling an allocation request involving
1867 	 * multiple dmaps.  we'll try to clean up by backing out any
1868 	 * allocation that has already happened for this request.  if
1869 	 * we fail in backing out the allocation, we'll mark the file
1870 	 * system to indicate that blocks have been leaked.
1871 	 */
1872       backout:
1873 
1874 	/* try to backout the allocations dmap by dmap.
1875 	 */
1876 	for (n = nblocks - n, b = blkno; n > 0;
1877 	     n -= BPERDMAP, b += BPERDMAP) {
1878 		/* get the buffer for this dmap.
1879 		 */
1880 		lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1881 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1882 		if (mp == NULL) {
1883 			/* could not back out.  mark the file system
1884 			 * to indicate that we have leaked blocks.
1885 			 */
1886 			jfs_error(bmp->db_ipbmap->i_sb,
1887 				  "I/O Error: Block Leakage\n");
1888 			continue;
1889 		}
1890 		dp = (struct dmap *) mp->data;
1891 
1892 		/* free the blocks is this dmap.
1893 		 */
1894 		if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1895 			/* could not back out.  mark the file system
1896 			 * to indicate that we have leaked blocks.
1897 			 */
1898 			release_metapage(mp);
1899 			jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n");
1900 			continue;
1901 		}
1902 
1903 		/* write the buffer.
1904 		 */
1905 		write_metapage(mp);
1906 	}
1907 
1908 	return (rc);
1909 }
1910 
1911 
1912 /*
1913  * NAME:	dbAllocDmapLev()
1914  *
1915  * FUNCTION:	attempt to allocate a specified number of contiguous blocks
1916  *		from a specified dmap.
1917  *
1918  *		this routine checks if the contiguous blocks are available.
1919  *		if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1920  *		returned.
1921  *
1922  * PARAMETERS:
1923  *	mp	-  pointer to bmap descriptor
1924  *	dp	-  pointer to dmap to attempt to allocate blocks from.
1925  *	l2nb	-  log2 number of contiguous block desired.
1926  *	nblocks	-  actual number of contiguous block desired.
1927  *	results	-  on successful return, set to the starting block number
1928  *		   of the newly allocated range.
1929  *
1930  * RETURN VALUES:
1931  *	0	- success
1932  *	-ENOSPC	- insufficient disk resources
1933  *	-EIO	- i/o error
1934  *
1935  * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1936  *	IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1937  */
1938 static int
dbAllocDmapLev(struct bmap * bmp,struct dmap * dp,int nblocks,int l2nb,s64 * results)1939 dbAllocDmapLev(struct bmap * bmp,
1940 	       struct dmap * dp, int nblocks, int l2nb, s64 * results)
1941 {
1942 	s64 blkno;
1943 	int leafidx, rc;
1944 
1945 	/* can't be more than a dmaps worth of blocks */
1946 	assert(l2nb <= L2BPERDMAP);
1947 
1948 	/* search the tree within the dmap page for sufficient
1949 	 * free space.  if sufficient free space is found, dbFindLeaf()
1950 	 * returns the index of the leaf at which free space was found.
1951 	 */
1952 	if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1953 		return -ENOSPC;
1954 
1955 	/* determine the block number within the file system corresponding
1956 	 * to the leaf at which free space was found.
1957 	 */
1958 	blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1959 
1960 	/* if not all bits of the dmap word are free, get the starting
1961 	 * bit number within the dmap word of the required string of free
1962 	 * bits and adjust the block number with this value.
1963 	 */
1964 	if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1965 		blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1966 
1967 	/* allocate the blocks */
1968 	if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1969 		*results = blkno;
1970 
1971 	return (rc);
1972 }
1973 
1974 
1975 /*
1976  * NAME:	dbAllocDmap()
1977  *
1978  * FUNCTION:	adjust the disk allocation map to reflect the allocation
1979  *		of a specified block range within a dmap.
1980  *
1981  *		this routine allocates the specified blocks from the dmap
1982  *		through a call to dbAllocBits(). if the allocation of the
1983  *		block range causes the maximum string of free blocks within
1984  *		the dmap to change (i.e. the value of the root of the dmap's
1985  *		dmtree), this routine will cause this change to be reflected
1986  *		up through the appropriate levels of the dmap control pages
1987  *		by a call to dbAdjCtl() for the L0 dmap control page that
1988  *		covers this dmap.
1989  *
1990  * PARAMETERS:
1991  *	bmp	-  pointer to bmap descriptor
1992  *	dp	-  pointer to dmap to allocate the block range from.
1993  *	blkno	-  starting block number of the block to be allocated.
1994  *	nblocks	-  number of blocks to be allocated.
1995  *
1996  * RETURN VALUES:
1997  *	0	- success
1998  *	-EIO	- i/o error
1999  *
2000  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2001  */
dbAllocDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2002 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2003 		       int nblocks)
2004 {
2005 	s8 oldroot;
2006 	int rc;
2007 
2008 	/* save the current value of the root (i.e. maximum free string)
2009 	 * of the dmap tree.
2010 	 */
2011 	oldroot = dp->tree.stree[ROOT];
2012 
2013 	/* allocate the specified (blocks) bits */
2014 	dbAllocBits(bmp, dp, blkno, nblocks);
2015 
2016 	/* if the root has not changed, done. */
2017 	if (dp->tree.stree[ROOT] == oldroot)
2018 		return (0);
2019 
2020 	/* root changed. bubble the change up to the dmap control pages.
2021 	 * if the adjustment of the upper level control pages fails,
2022 	 * backout the bit allocation (thus making everything consistent).
2023 	 */
2024 	if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
2025 		dbFreeBits(bmp, dp, blkno, nblocks);
2026 
2027 	return (rc);
2028 }
2029 
2030 
2031 /*
2032  * NAME:	dbFreeDmap()
2033  *
2034  * FUNCTION:	adjust the disk allocation map to reflect the allocation
2035  *		of a specified block range within a dmap.
2036  *
2037  *		this routine frees the specified blocks from the dmap through
2038  *		a call to dbFreeBits(). if the deallocation of the block range
2039  *		causes the maximum string of free blocks within the dmap to
2040  *		change (i.e. the value of the root of the dmap's dmtree), this
2041  *		routine will cause this change to be reflected up through the
2042  *		appropriate levels of the dmap control pages by a call to
2043  *		dbAdjCtl() for the L0 dmap control page that covers this dmap.
2044  *
2045  * PARAMETERS:
2046  *	bmp	-  pointer to bmap descriptor
2047  *	dp	-  pointer to dmap to free the block range from.
2048  *	blkno	-  starting block number of the block to be freed.
2049  *	nblocks	-  number of blocks to be freed.
2050  *
2051  * RETURN VALUES:
2052  *	0	- success
2053  *	-EIO	- i/o error
2054  *
2055  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2056  */
dbFreeDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2057 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2058 		      int nblocks)
2059 {
2060 	s8 oldroot;
2061 	int rc = 0, word;
2062 
2063 	/* save the current value of the root (i.e. maximum free string)
2064 	 * of the dmap tree.
2065 	 */
2066 	oldroot = dp->tree.stree[ROOT];
2067 
2068 	/* free the specified (blocks) bits */
2069 	rc = dbFreeBits(bmp, dp, blkno, nblocks);
2070 
2071 	/* if error or the root has not changed, done. */
2072 	if (rc || (dp->tree.stree[ROOT] == oldroot))
2073 		return (rc);
2074 
2075 	/* root changed. bubble the change up to the dmap control pages.
2076 	 * if the adjustment of the upper level control pages fails,
2077 	 * backout the deallocation.
2078 	 */
2079 	if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2080 		word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2081 
2082 		/* as part of backing out the deallocation, we will have
2083 		 * to back split the dmap tree if the deallocation caused
2084 		 * the freed blocks to become part of a larger binary buddy
2085 		 * system.
2086 		 */
2087 		if (dp->tree.stree[word] == NOFREE)
2088 			dbBackSplit((dmtree_t *) & dp->tree, word);
2089 
2090 		dbAllocBits(bmp, dp, blkno, nblocks);
2091 	}
2092 
2093 	return (rc);
2094 }
2095 
2096 
2097 /*
2098  * NAME:	dbAllocBits()
2099  *
2100  * FUNCTION:	allocate a specified block range from a dmap.
2101  *
2102  *		this routine updates the dmap to reflect the working
2103  *		state allocation of the specified block range. it directly
2104  *		updates the bits of the working map and causes the adjustment
2105  *		of the binary buddy system described by the dmap's dmtree
2106  *		leaves to reflect the bits allocated.  it also causes the
2107  *		dmap's dmtree, as a whole, to reflect the allocated range.
2108  *
2109  * PARAMETERS:
2110  *	bmp	-  pointer to bmap descriptor
2111  *	dp	-  pointer to dmap to allocate bits from.
2112  *	blkno	-  starting block number of the bits to be allocated.
2113  *	nblocks	-  number of bits to be allocated.
2114  *
2115  * RETURN VALUES: none
2116  *
2117  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2118  */
dbAllocBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2119 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2120 			int nblocks)
2121 {
2122 	int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2123 	dmtree_t *tp = (dmtree_t *) & dp->tree;
2124 	int size;
2125 	s8 *leaf;
2126 
2127 	/* pick up a pointer to the leaves of the dmap tree */
2128 	leaf = dp->tree.stree + LEAFIND;
2129 
2130 	/* determine the bit number and word within the dmap of the
2131 	 * starting block.
2132 	 */
2133 	dbitno = blkno & (BPERDMAP - 1);
2134 	word = dbitno >> L2DBWORD;
2135 
2136 	/* block range better be within the dmap */
2137 	assert(dbitno + nblocks <= BPERDMAP);
2138 
2139 	/* allocate the bits of the dmap's words corresponding to the block
2140 	 * range. not all bits of the first and last words may be contained
2141 	 * within the block range.  if this is the case, we'll work against
2142 	 * those words (i.e. partial first and/or last) on an individual basis
2143 	 * (a single pass), allocating the bits of interest by hand and
2144 	 * updating the leaf corresponding to the dmap word. a single pass
2145 	 * will be used for all dmap words fully contained within the
2146 	 * specified range.  within this pass, the bits of all fully contained
2147 	 * dmap words will be marked as free in a single shot and the leaves
2148 	 * will be updated. a single leaf may describe the free space of
2149 	 * multiple dmap words, so we may update only a subset of the actual
2150 	 * leaves corresponding to the dmap words of the block range.
2151 	 */
2152 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2153 		/* determine the bit number within the word and
2154 		 * the number of bits within the word.
2155 		 */
2156 		wbitno = dbitno & (DBWORD - 1);
2157 		nb = min(rembits, DBWORD - wbitno);
2158 
2159 		/* check if only part of a word is to be allocated.
2160 		 */
2161 		if (nb < DBWORD) {
2162 			/* allocate (set to 1) the appropriate bits within
2163 			 * this dmap word.
2164 			 */
2165 			dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2166 						      >> wbitno);
2167 
2168 			/* update the leaf for this dmap word. in addition
2169 			 * to setting the leaf value to the binary buddy max
2170 			 * of the updated dmap word, dbSplit() will split
2171 			 * the binary system of the leaves if need be.
2172 			 */
2173 			dbSplit(tp, word, BUDMIN,
2174 				dbMaxBud((u8 *) & dp->wmap[word]));
2175 
2176 			word += 1;
2177 		} else {
2178 			/* one or more dmap words are fully contained
2179 			 * within the block range.  determine how many
2180 			 * words and allocate (set to 1) the bits of these
2181 			 * words.
2182 			 */
2183 			nwords = rembits >> L2DBWORD;
2184 			memset(&dp->wmap[word], (int) ONES, nwords * 4);
2185 
2186 			/* determine how many bits.
2187 			 */
2188 			nb = nwords << L2DBWORD;
2189 
2190 			/* now update the appropriate leaves to reflect
2191 			 * the allocated words.
2192 			 */
2193 			for (; nwords > 0; nwords -= nw) {
2194 				if (leaf[word] < BUDMIN) {
2195 					jfs_error(bmp->db_ipbmap->i_sb,
2196 						  "leaf page corrupt\n");
2197 					break;
2198 				}
2199 
2200 				/* determine what the leaf value should be
2201 				 * updated to as the minimum of the l2 number
2202 				 * of bits being allocated and the l2 number
2203 				 * of bits currently described by this leaf.
2204 				 */
2205 				size = min_t(int, leaf[word],
2206 					     NLSTOL2BSZ(nwords));
2207 
2208 				/* update the leaf to reflect the allocation.
2209 				 * in addition to setting the leaf value to
2210 				 * NOFREE, dbSplit() will split the binary
2211 				 * system of the leaves to reflect the current
2212 				 * allocation (size).
2213 				 */
2214 				dbSplit(tp, word, size, NOFREE);
2215 
2216 				/* get the number of dmap words handled */
2217 				nw = BUDSIZE(size, BUDMIN);
2218 				word += nw;
2219 			}
2220 		}
2221 	}
2222 
2223 	/* update the free count for this dmap */
2224 	le32_add_cpu(&dp->nfree, -nblocks);
2225 
2226 	BMAP_LOCK(bmp);
2227 
2228 	/* if this allocation group is completely free,
2229 	 * update the maximum allocation group number if this allocation
2230 	 * group is the new max.
2231 	 */
2232 	agno = blkno >> bmp->db_agl2size;
2233 	if (agno > bmp->db_maxag)
2234 		bmp->db_maxag = agno;
2235 
2236 	/* update the free count for the allocation group and map */
2237 	bmp->db_agfree[agno] -= nblocks;
2238 	bmp->db_nfree -= nblocks;
2239 
2240 	BMAP_UNLOCK(bmp);
2241 }
2242 
2243 
2244 /*
2245  * NAME:	dbFreeBits()
2246  *
2247  * FUNCTION:	free a specified block range from a dmap.
2248  *
2249  *		this routine updates the dmap to reflect the working
2250  *		state allocation of the specified block range. it directly
2251  *		updates the bits of the working map and causes the adjustment
2252  *		of the binary buddy system described by the dmap's dmtree
2253  *		leaves to reflect the bits freed.  it also causes the dmap's
2254  *		dmtree, as a whole, to reflect the deallocated range.
2255  *
2256  * PARAMETERS:
2257  *	bmp	-  pointer to bmap descriptor
2258  *	dp	-  pointer to dmap to free bits from.
2259  *	blkno	-  starting block number of the bits to be freed.
2260  *	nblocks	-  number of bits to be freed.
2261  *
2262  * RETURN VALUES: 0 for success
2263  *
2264  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2265  */
dbFreeBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2266 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2267 		       int nblocks)
2268 {
2269 	int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2270 	dmtree_t *tp = (dmtree_t *) & dp->tree;
2271 	int rc = 0;
2272 	int size;
2273 
2274 	/* determine the bit number and word within the dmap of the
2275 	 * starting block.
2276 	 */
2277 	dbitno = blkno & (BPERDMAP - 1);
2278 	word = dbitno >> L2DBWORD;
2279 
2280 	/* block range better be within the dmap.
2281 	 */
2282 	assert(dbitno + nblocks <= BPERDMAP);
2283 
2284 	/* free the bits of the dmaps words corresponding to the block range.
2285 	 * not all bits of the first and last words may be contained within
2286 	 * the block range.  if this is the case, we'll work against those
2287 	 * words (i.e. partial first and/or last) on an individual basis
2288 	 * (a single pass), freeing the bits of interest by hand and updating
2289 	 * the leaf corresponding to the dmap word. a single pass will be used
2290 	 * for all dmap words fully contained within the specified range.
2291 	 * within this pass, the bits of all fully contained dmap words will
2292 	 * be marked as free in a single shot and the leaves will be updated. a
2293 	 * single leaf may describe the free space of multiple dmap words,
2294 	 * so we may update only a subset of the actual leaves corresponding
2295 	 * to the dmap words of the block range.
2296 	 *
2297 	 * dbJoin() is used to update leaf values and will join the binary
2298 	 * buddy system of the leaves if the new leaf values indicate this
2299 	 * should be done.
2300 	 */
2301 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2302 		/* determine the bit number within the word and
2303 		 * the number of bits within the word.
2304 		 */
2305 		wbitno = dbitno & (DBWORD - 1);
2306 		nb = min(rembits, DBWORD - wbitno);
2307 
2308 		/* check if only part of a word is to be freed.
2309 		 */
2310 		if (nb < DBWORD) {
2311 			/* free (zero) the appropriate bits within this
2312 			 * dmap word.
2313 			 */
2314 			dp->wmap[word] &=
2315 			    cpu_to_le32(~(ONES << (DBWORD - nb)
2316 					  >> wbitno));
2317 
2318 			/* update the leaf for this dmap word.
2319 			 */
2320 			rc = dbJoin(tp, word,
2321 				    dbMaxBud((u8 *) & dp->wmap[word]));
2322 			if (rc)
2323 				return rc;
2324 
2325 			word += 1;
2326 		} else {
2327 			/* one or more dmap words are fully contained
2328 			 * within the block range.  determine how many
2329 			 * words and free (zero) the bits of these words.
2330 			 */
2331 			nwords = rembits >> L2DBWORD;
2332 			memset(&dp->wmap[word], 0, nwords * 4);
2333 
2334 			/* determine how many bits.
2335 			 */
2336 			nb = nwords << L2DBWORD;
2337 
2338 			/* now update the appropriate leaves to reflect
2339 			 * the freed words.
2340 			 */
2341 			for (; nwords > 0; nwords -= nw) {
2342 				/* determine what the leaf value should be
2343 				 * updated to as the minimum of the l2 number
2344 				 * of bits being freed and the l2 (max) number
2345 				 * of bits that can be described by this leaf.
2346 				 */
2347 				size =
2348 				    min(LITOL2BSZ
2349 					(word, L2LPERDMAP, BUDMIN),
2350 					NLSTOL2BSZ(nwords));
2351 
2352 				/* update the leaf.
2353 				 */
2354 				rc = dbJoin(tp, word, size);
2355 				if (rc)
2356 					return rc;
2357 
2358 				/* get the number of dmap words handled.
2359 				 */
2360 				nw = BUDSIZE(size, BUDMIN);
2361 				word += nw;
2362 			}
2363 		}
2364 	}
2365 
2366 	/* update the free count for this dmap.
2367 	 */
2368 	le32_add_cpu(&dp->nfree, nblocks);
2369 
2370 	BMAP_LOCK(bmp);
2371 
2372 	/* update the free count for the allocation group and
2373 	 * map.
2374 	 */
2375 	agno = blkno >> bmp->db_agl2size;
2376 	bmp->db_nfree += nblocks;
2377 	bmp->db_agfree[agno] += nblocks;
2378 
2379 	/* check if this allocation group is not completely free and
2380 	 * if it is currently the maximum (rightmost) allocation group.
2381 	 * if so, establish the new maximum allocation group number by
2382 	 * searching left for the first allocation group with allocation.
2383 	 */
2384 	if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2385 	    (agno == bmp->db_numag - 1 &&
2386 	     bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2387 		while (bmp->db_maxag > 0) {
2388 			bmp->db_maxag -= 1;
2389 			if (bmp->db_agfree[bmp->db_maxag] !=
2390 			    bmp->db_agsize)
2391 				break;
2392 		}
2393 
2394 		/* re-establish the allocation group preference if the
2395 		 * current preference is right of the maximum allocation
2396 		 * group.
2397 		 */
2398 		if (bmp->db_agpref > bmp->db_maxag)
2399 			bmp->db_agpref = bmp->db_maxag;
2400 	}
2401 
2402 	BMAP_UNLOCK(bmp);
2403 
2404 	return 0;
2405 }
2406 
2407 
2408 /*
2409  * NAME:	dbAdjCtl()
2410  *
2411  * FUNCTION:	adjust a dmap control page at a specified level to reflect
2412  *		the change in a lower level dmap or dmap control page's
2413  *		maximum string of free blocks (i.e. a change in the root
2414  *		of the lower level object's dmtree) due to the allocation
2415  *		or deallocation of a range of blocks with a single dmap.
2416  *
2417  *		on entry, this routine is provided with the new value of
2418  *		the lower level dmap or dmap control page root and the
2419  *		starting block number of the block range whose allocation
2420  *		or deallocation resulted in the root change.  this range
2421  *		is respresented by a single leaf of the current dmapctl
2422  *		and the leaf will be updated with this value, possibly
2423  *		causing a binary buddy system within the leaves to be
2424  *		split or joined.  the update may also cause the dmapctl's
2425  *		dmtree to be updated.
2426  *
2427  *		if the adjustment of the dmap control page, itself, causes its
2428  *		root to change, this change will be bubbled up to the next dmap
2429  *		control level by a recursive call to this routine, specifying
2430  *		the new root value and the next dmap control page level to
2431  *		be adjusted.
2432  * PARAMETERS:
2433  *	bmp	-  pointer to bmap descriptor
2434  *	blkno	-  the first block of a block range within a dmap.  it is
2435  *		   the allocation or deallocation of this block range that
2436  *		   requires the dmap control page to be adjusted.
2437  *	newval	-  the new value of the lower level dmap or dmap control
2438  *		   page root.
2439  *	alloc	-  'true' if adjustment is due to an allocation.
2440  *	level	-  current level of dmap control page (i.e. L0, L1, L2) to
2441  *		   be adjusted.
2442  *
2443  * RETURN VALUES:
2444  *	0	- success
2445  *	-EIO	- i/o error
2446  *
2447  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2448  */
2449 static int
dbAdjCtl(struct bmap * bmp,s64 blkno,int newval,int alloc,int level)2450 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2451 {
2452 	struct metapage *mp;
2453 	s8 oldroot;
2454 	int oldval;
2455 	s64 lblkno;
2456 	struct dmapctl *dcp;
2457 	int rc, leafno, ti;
2458 
2459 	/* get the buffer for the dmap control page for the specified
2460 	 * block number and control page level.
2461 	 */
2462 	lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2463 	mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2464 	if (mp == NULL)
2465 		return -EIO;
2466 	dcp = (struct dmapctl *) mp->data;
2467 
2468 	if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2469 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
2470 		release_metapage(mp);
2471 		return -EIO;
2472 	}
2473 
2474 	/* determine the leaf number corresponding to the block and
2475 	 * the index within the dmap control tree.
2476 	 */
2477 	leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2478 	ti = leafno + le32_to_cpu(dcp->leafidx);
2479 
2480 	/* save the current leaf value and the current root level (i.e.
2481 	 * maximum l2 free string described by this dmapctl).
2482 	 */
2483 	oldval = dcp->stree[ti];
2484 	oldroot = dcp->stree[ROOT];
2485 
2486 	/* check if this is a control page update for an allocation.
2487 	 * if so, update the leaf to reflect the new leaf value using
2488 	 * dbSplit(); otherwise (deallocation), use dbJoin() to update
2489 	 * the leaf with the new value.  in addition to updating the
2490 	 * leaf, dbSplit() will also split the binary buddy system of
2491 	 * the leaves, if required, and bubble new values within the
2492 	 * dmapctl tree, if required.  similarly, dbJoin() will join
2493 	 * the binary buddy system of leaves and bubble new values up
2494 	 * the dmapctl tree as required by the new leaf value.
2495 	 */
2496 	if (alloc) {
2497 		/* check if we are in the middle of a binary buddy
2498 		 * system.  this happens when we are performing the
2499 		 * first allocation out of an allocation group that
2500 		 * is part (not the first part) of a larger binary
2501 		 * buddy system.  if we are in the middle, back split
2502 		 * the system prior to calling dbSplit() which assumes
2503 		 * that it is at the front of a binary buddy system.
2504 		 */
2505 		if (oldval == NOFREE) {
2506 			rc = dbBackSplit((dmtree_t *) dcp, leafno);
2507 			if (rc) {
2508 				release_metapage(mp);
2509 				return rc;
2510 			}
2511 			oldval = dcp->stree[ti];
2512 		}
2513 		dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2514 	} else {
2515 		rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2516 		if (rc) {
2517 			release_metapage(mp);
2518 			return rc;
2519 		}
2520 	}
2521 
2522 	/* check if the root of the current dmap control page changed due
2523 	 * to the update and if the current dmap control page is not at
2524 	 * the current top level (i.e. L0, L1, L2) of the map.  if so (i.e.
2525 	 * root changed and this is not the top level), call this routine
2526 	 * again (recursion) for the next higher level of the mapping to
2527 	 * reflect the change in root for the current dmap control page.
2528 	 */
2529 	if (dcp->stree[ROOT] != oldroot) {
2530 		/* are we below the top level of the map.  if so,
2531 		 * bubble the root up to the next higher level.
2532 		 */
2533 		if (level < bmp->db_maxlevel) {
2534 			/* bubble up the new root of this dmap control page to
2535 			 * the next level.
2536 			 */
2537 			if ((rc =
2538 			     dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2539 				      level + 1))) {
2540 				/* something went wrong in bubbling up the new
2541 				 * root value, so backout the changes to the
2542 				 * current dmap control page.
2543 				 */
2544 				if (alloc) {
2545 					dbJoin((dmtree_t *) dcp, leafno,
2546 					       oldval);
2547 				} else {
2548 					/* the dbJoin() above might have
2549 					 * caused a larger binary buddy system
2550 					 * to form and we may now be in the
2551 					 * middle of it.  if this is the case,
2552 					 * back split the buddies.
2553 					 */
2554 					if (dcp->stree[ti] == NOFREE)
2555 						dbBackSplit((dmtree_t *)
2556 							    dcp, leafno);
2557 					dbSplit((dmtree_t *) dcp, leafno,
2558 						dcp->budmin, oldval);
2559 				}
2560 
2561 				/* release the buffer and return the error.
2562 				 */
2563 				release_metapage(mp);
2564 				return (rc);
2565 			}
2566 		} else {
2567 			/* we're at the top level of the map. update
2568 			 * the bmap control page to reflect the size
2569 			 * of the maximum free buddy system.
2570 			 */
2571 			assert(level == bmp->db_maxlevel);
2572 			if (bmp->db_maxfreebud != oldroot) {
2573 				jfs_error(bmp->db_ipbmap->i_sb,
2574 					  "the maximum free buddy is not the old root\n");
2575 			}
2576 			bmp->db_maxfreebud = dcp->stree[ROOT];
2577 		}
2578 	}
2579 
2580 	/* write the buffer.
2581 	 */
2582 	write_metapage(mp);
2583 
2584 	return (0);
2585 }
2586 
2587 
2588 /*
2589  * NAME:	dbSplit()
2590  *
2591  * FUNCTION:	update the leaf of a dmtree with a new value, splitting
2592  *		the leaf from the binary buddy system of the dmtree's
2593  *		leaves, as required.
2594  *
2595  * PARAMETERS:
2596  *	tp	- pointer to the tree containing the leaf.
2597  *	leafno	- the number of the leaf to be updated.
2598  *	splitsz	- the size the binary buddy system starting at the leaf
2599  *		  must be split to, specified as the log2 number of blocks.
2600  *	newval	- the new value for the leaf.
2601  *
2602  * RETURN VALUES: none
2603  *
2604  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2605  */
dbSplit(dmtree_t * tp,int leafno,int splitsz,int newval)2606 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2607 {
2608 	int budsz;
2609 	int cursz;
2610 	s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2611 
2612 	/* check if the leaf needs to be split.
2613 	 */
2614 	if (leaf[leafno] > tp->dmt_budmin) {
2615 		/* the split occurs by cutting the buddy system in half
2616 		 * at the specified leaf until we reach the specified
2617 		 * size.  pick up the starting split size (current size
2618 		 * - 1 in l2) and the corresponding buddy size.
2619 		 */
2620 		cursz = leaf[leafno] - 1;
2621 		budsz = BUDSIZE(cursz, tp->dmt_budmin);
2622 
2623 		/* split until we reach the specified size.
2624 		 */
2625 		while (cursz >= splitsz) {
2626 			/* update the buddy's leaf with its new value.
2627 			 */
2628 			dbAdjTree(tp, leafno ^ budsz, cursz);
2629 
2630 			/* on to the next size and buddy.
2631 			 */
2632 			cursz -= 1;
2633 			budsz >>= 1;
2634 		}
2635 	}
2636 
2637 	/* adjust the dmap tree to reflect the specified leaf's new
2638 	 * value.
2639 	 */
2640 	dbAdjTree(tp, leafno, newval);
2641 }
2642 
2643 
2644 /*
2645  * NAME:	dbBackSplit()
2646  *
2647  * FUNCTION:	back split the binary buddy system of dmtree leaves
2648  *		that hold a specified leaf until the specified leaf
2649  *		starts its own binary buddy system.
2650  *
2651  *		the allocators typically perform allocations at the start
2652  *		of binary buddy systems and dbSplit() is used to accomplish
2653  *		any required splits.  in some cases, however, allocation
2654  *		may occur in the middle of a binary system and requires a
2655  *		back split, with the split proceeding out from the middle of
2656  *		the system (less efficient) rather than the start of the
2657  *		system (more efficient).  the cases in which a back split
2658  *		is required are rare and are limited to the first allocation
2659  *		within an allocation group which is a part (not first part)
2660  *		of a larger binary buddy system and a few exception cases
2661  *		in which a previous join operation must be backed out.
2662  *
2663  * PARAMETERS:
2664  *	tp	- pointer to the tree containing the leaf.
2665  *	leafno	- the number of the leaf to be updated.
2666  *
2667  * RETURN VALUES: none
2668  *
2669  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2670  */
dbBackSplit(dmtree_t * tp,int leafno)2671 static int dbBackSplit(dmtree_t * tp, int leafno)
2672 {
2673 	int budsz, bud, w, bsz, size;
2674 	int cursz;
2675 	s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2676 
2677 	/* leaf should be part (not first part) of a binary
2678 	 * buddy system.
2679 	 */
2680 	assert(leaf[leafno] == NOFREE);
2681 
2682 	/* the back split is accomplished by iteratively finding the leaf
2683 	 * that starts the buddy system that contains the specified leaf and
2684 	 * splitting that system in two.  this iteration continues until
2685 	 * the specified leaf becomes the start of a buddy system.
2686 	 *
2687 	 * determine maximum possible l2 size for the specified leaf.
2688 	 */
2689 	size =
2690 	    LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2691 		      tp->dmt_budmin);
2692 
2693 	/* determine the number of leaves covered by this size.  this
2694 	 * is the buddy size that we will start with as we search for
2695 	 * the buddy system that contains the specified leaf.
2696 	 */
2697 	budsz = BUDSIZE(size, tp->dmt_budmin);
2698 
2699 	/* back split.
2700 	 */
2701 	while (leaf[leafno] == NOFREE) {
2702 		/* find the leftmost buddy leaf.
2703 		 */
2704 		for (w = leafno, bsz = budsz;; bsz <<= 1,
2705 		     w = (w < bud) ? w : bud) {
2706 			if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2707 				jfs_err("JFS: block map error in dbBackSplit");
2708 				return -EIO;
2709 			}
2710 
2711 			/* determine the buddy.
2712 			 */
2713 			bud = w ^ bsz;
2714 
2715 			/* check if this buddy is the start of the system.
2716 			 */
2717 			if (leaf[bud] != NOFREE) {
2718 				/* split the leaf at the start of the
2719 				 * system in two.
2720 				 */
2721 				cursz = leaf[bud] - 1;
2722 				dbSplit(tp, bud, cursz, cursz);
2723 				break;
2724 			}
2725 		}
2726 	}
2727 
2728 	if (leaf[leafno] != size) {
2729 		jfs_err("JFS: wrong leaf value in dbBackSplit");
2730 		return -EIO;
2731 	}
2732 	return 0;
2733 }
2734 
2735 
2736 /*
2737  * NAME:	dbJoin()
2738  *
2739  * FUNCTION:	update the leaf of a dmtree with a new value, joining
2740  *		the leaf with other leaves of the dmtree into a multi-leaf
2741  *		binary buddy system, as required.
2742  *
2743  * PARAMETERS:
2744  *	tp	- pointer to the tree containing the leaf.
2745  *	leafno	- the number of the leaf to be updated.
2746  *	newval	- the new value for the leaf.
2747  *
2748  * RETURN VALUES: none
2749  */
dbJoin(dmtree_t * tp,int leafno,int newval)2750 static int dbJoin(dmtree_t * tp, int leafno, int newval)
2751 {
2752 	int budsz, buddy;
2753 	s8 *leaf;
2754 
2755 	/* can the new leaf value require a join with other leaves ?
2756 	 */
2757 	if (newval >= tp->dmt_budmin) {
2758 		/* pickup a pointer to the leaves of the tree.
2759 		 */
2760 		leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2761 
2762 		/* try to join the specified leaf into a large binary
2763 		 * buddy system.  the join proceeds by attempting to join
2764 		 * the specified leafno with its buddy (leaf) at new value.
2765 		 * if the join occurs, we attempt to join the left leaf
2766 		 * of the joined buddies with its buddy at new value + 1.
2767 		 * we continue to join until we find a buddy that cannot be
2768 		 * joined (does not have a value equal to the size of the
2769 		 * last join) or until all leaves have been joined into a
2770 		 * single system.
2771 		 *
2772 		 * get the buddy size (number of words covered) of
2773 		 * the new value.
2774 		 */
2775 		budsz = BUDSIZE(newval, tp->dmt_budmin);
2776 
2777 		/* try to join.
2778 		 */
2779 		while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2780 			/* get the buddy leaf.
2781 			 */
2782 			buddy = leafno ^ budsz;
2783 
2784 			/* if the leaf's new value is greater than its
2785 			 * buddy's value, we join no more.
2786 			 */
2787 			if (newval > leaf[buddy])
2788 				break;
2789 
2790 			/* It shouldn't be less */
2791 			if (newval < leaf[buddy])
2792 				return -EIO;
2793 
2794 			/* check which (leafno or buddy) is the left buddy.
2795 			 * the left buddy gets to claim the blocks resulting
2796 			 * from the join while the right gets to claim none.
2797 			 * the left buddy is also eligible to participate in
2798 			 * a join at the next higher level while the right
2799 			 * is not.
2800 			 *
2801 			 */
2802 			if (leafno < buddy) {
2803 				/* leafno is the left buddy.
2804 				 */
2805 				dbAdjTree(tp, buddy, NOFREE);
2806 			} else {
2807 				/* buddy is the left buddy and becomes
2808 				 * leafno.
2809 				 */
2810 				dbAdjTree(tp, leafno, NOFREE);
2811 				leafno = buddy;
2812 			}
2813 
2814 			/* on to try the next join.
2815 			 */
2816 			newval += 1;
2817 			budsz <<= 1;
2818 		}
2819 	}
2820 
2821 	/* update the leaf value.
2822 	 */
2823 	dbAdjTree(tp, leafno, newval);
2824 
2825 	return 0;
2826 }
2827 
2828 
2829 /*
2830  * NAME:	dbAdjTree()
2831  *
2832  * FUNCTION:	update a leaf of a dmtree with a new value, adjusting
2833  *		the dmtree, as required, to reflect the new leaf value.
2834  *		the combination of any buddies must already be done before
2835  *		this is called.
2836  *
2837  * PARAMETERS:
2838  *	tp	- pointer to the tree to be adjusted.
2839  *	leafno	- the number of the leaf to be updated.
2840  *	newval	- the new value for the leaf.
2841  *
2842  * RETURN VALUES: none
2843  */
dbAdjTree(dmtree_t * tp,int leafno,int newval)2844 static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2845 {
2846 	int lp, pp, k;
2847 	int max;
2848 
2849 	/* pick up the index of the leaf for this leafno.
2850 	 */
2851 	lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2852 
2853 	/* is the current value the same as the old value ?  if so,
2854 	 * there is nothing to do.
2855 	 */
2856 	if (tp->dmt_stree[lp] == newval)
2857 		return;
2858 
2859 	/* set the new value.
2860 	 */
2861 	tp->dmt_stree[lp] = newval;
2862 
2863 	/* bubble the new value up the tree as required.
2864 	 */
2865 	for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2866 		/* get the index of the first leaf of the 4 leaf
2867 		 * group containing the specified leaf (leafno).
2868 		 */
2869 		lp = ((lp - 1) & ~0x03) + 1;
2870 
2871 		/* get the index of the parent of this 4 leaf group.
2872 		 */
2873 		pp = (lp - 1) >> 2;
2874 
2875 		/* determine the maximum of the 4 leaves.
2876 		 */
2877 		max = TREEMAX(&tp->dmt_stree[lp]);
2878 
2879 		/* if the maximum of the 4 is the same as the
2880 		 * parent's value, we're done.
2881 		 */
2882 		if (tp->dmt_stree[pp] == max)
2883 			break;
2884 
2885 		/* parent gets new value.
2886 		 */
2887 		tp->dmt_stree[pp] = max;
2888 
2889 		/* parent becomes leaf for next go-round.
2890 		 */
2891 		lp = pp;
2892 	}
2893 }
2894 
2895 
2896 /*
2897  * NAME:	dbFindLeaf()
2898  *
2899  * FUNCTION:	search a dmtree_t for sufficient free blocks, returning
2900  *		the index of a leaf describing the free blocks if
2901  *		sufficient free blocks are found.
2902  *
2903  *		the search starts at the top of the dmtree_t tree and
2904  *		proceeds down the tree to the leftmost leaf with sufficient
2905  *		free space.
2906  *
2907  * PARAMETERS:
2908  *	tp	- pointer to the tree to be searched.
2909  *	l2nb	- log2 number of free blocks to search for.
2910  *	leafidx	- return pointer to be set to the index of the leaf
2911  *		  describing at least l2nb free blocks if sufficient
2912  *		  free blocks are found.
2913  *
2914  * RETURN VALUES:
2915  *	0	- success
2916  *	-ENOSPC	- insufficient free blocks.
2917  */
dbFindLeaf(dmtree_t * tp,int l2nb,int * leafidx)2918 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2919 {
2920 	int ti, n = 0, k, x = 0;
2921 
2922 	/* first check the root of the tree to see if there is
2923 	 * sufficient free space.
2924 	 */
2925 	if (l2nb > tp->dmt_stree[ROOT])
2926 		return -ENOSPC;
2927 
2928 	/* sufficient free space available. now search down the tree
2929 	 * starting at the next level for the leftmost leaf that
2930 	 * describes sufficient free space.
2931 	 */
2932 	for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2933 	     k > 0; k--, ti = ((ti + n) << 2) + 1) {
2934 		/* search the four nodes at this level, starting from
2935 		 * the left.
2936 		 */
2937 		for (x = ti, n = 0; n < 4; n++) {
2938 			/* sufficient free space found.  move to the next
2939 			 * level (or quit if this is the last level).
2940 			 */
2941 			if (l2nb <= tp->dmt_stree[x + n])
2942 				break;
2943 		}
2944 
2945 		/* better have found something since the higher
2946 		 * levels of the tree said it was here.
2947 		 */
2948 		assert(n < 4);
2949 	}
2950 
2951 	/* set the return to the leftmost leaf describing sufficient
2952 	 * free space.
2953 	 */
2954 	*leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2955 
2956 	return (0);
2957 }
2958 
2959 
2960 /*
2961  * NAME:	dbFindBits()
2962  *
2963  * FUNCTION:	find a specified number of binary buddy free bits within a
2964  *		dmap bitmap word value.
2965  *
2966  *		this routine searches the bitmap value for (1 << l2nb) free
2967  *		bits at (1 << l2nb) alignments within the value.
2968  *
2969  * PARAMETERS:
2970  *	word	-  dmap bitmap word value.
2971  *	l2nb	-  number of free bits specified as a log2 number.
2972  *
2973  * RETURN VALUES:
2974  *	starting bit number of free bits.
2975  */
dbFindBits(u32 word,int l2nb)2976 static int dbFindBits(u32 word, int l2nb)
2977 {
2978 	int bitno, nb;
2979 	u32 mask;
2980 
2981 	/* get the number of bits.
2982 	 */
2983 	nb = 1 << l2nb;
2984 	assert(nb <= DBWORD);
2985 
2986 	/* complement the word so we can use a mask (i.e. 0s represent
2987 	 * free bits) and compute the mask.
2988 	 */
2989 	word = ~word;
2990 	mask = ONES << (DBWORD - nb);
2991 
2992 	/* scan the word for nb free bits at nb alignments.
2993 	 */
2994 	for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2995 		if ((mask & word) == mask)
2996 			break;
2997 	}
2998 
2999 	ASSERT(bitno < 32);
3000 
3001 	/* return the bit number.
3002 	 */
3003 	return (bitno);
3004 }
3005 
3006 
3007 /*
3008  * NAME:	dbMaxBud(u8 *cp)
3009  *
3010  * FUNCTION:	determine the largest binary buddy string of free
3011  *		bits within 32-bits of the map.
3012  *
3013  * PARAMETERS:
3014  *	cp	-  pointer to the 32-bit value.
3015  *
3016  * RETURN VALUES:
3017  *	largest binary buddy of free bits within a dmap word.
3018  */
dbMaxBud(u8 * cp)3019 static int dbMaxBud(u8 * cp)
3020 {
3021 	signed char tmp1, tmp2;
3022 
3023 	/* check if the wmap word is all free. if so, the
3024 	 * free buddy size is BUDMIN.
3025 	 */
3026 	if (*((uint *) cp) == 0)
3027 		return (BUDMIN);
3028 
3029 	/* check if the wmap word is half free. if so, the
3030 	 * free buddy size is BUDMIN-1.
3031 	 */
3032 	if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
3033 		return (BUDMIN - 1);
3034 
3035 	/* not all free or half free. determine the free buddy
3036 	 * size thru table lookup using quarters of the wmap word.
3037 	 */
3038 	tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
3039 	tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
3040 	return (max(tmp1, tmp2));
3041 }
3042 
3043 
3044 /*
3045  * NAME:	cnttz(uint word)
3046  *
3047  * FUNCTION:	determine the number of trailing zeros within a 32-bit
3048  *		value.
3049  *
3050  * PARAMETERS:
3051  *	value	-  32-bit value to be examined.
3052  *
3053  * RETURN VALUES:
3054  *	count of trailing zeros
3055  */
cnttz(u32 word)3056 static int cnttz(u32 word)
3057 {
3058 	int n;
3059 
3060 	for (n = 0; n < 32; n++, word >>= 1) {
3061 		if (word & 0x01)
3062 			break;
3063 	}
3064 
3065 	return (n);
3066 }
3067 
3068 
3069 /*
3070  * NAME:	cntlz(u32 value)
3071  *
3072  * FUNCTION:	determine the number of leading zeros within a 32-bit
3073  *		value.
3074  *
3075  * PARAMETERS:
3076  *	value	-  32-bit value to be examined.
3077  *
3078  * RETURN VALUES:
3079  *	count of leading zeros
3080  */
cntlz(u32 value)3081 static int cntlz(u32 value)
3082 {
3083 	int n;
3084 
3085 	for (n = 0; n < 32; n++, value <<= 1) {
3086 		if (value & HIGHORDER)
3087 			break;
3088 	}
3089 	return (n);
3090 }
3091 
3092 
3093 /*
3094  * NAME:	blkstol2(s64 nb)
3095  *
3096  * FUNCTION:	convert a block count to its log2 value. if the block
3097  *		count is not a l2 multiple, it is rounded up to the next
3098  *		larger l2 multiple.
3099  *
3100  * PARAMETERS:
3101  *	nb	-  number of blocks
3102  *
3103  * RETURN VALUES:
3104  *	log2 number of blocks
3105  */
blkstol2(s64 nb)3106 static int blkstol2(s64 nb)
3107 {
3108 	int l2nb;
3109 	s64 mask;		/* meant to be signed */
3110 
3111 	mask = (s64) 1 << (64 - 1);
3112 
3113 	/* count the leading bits.
3114 	 */
3115 	for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3116 		/* leading bit found.
3117 		 */
3118 		if (nb & mask) {
3119 			/* determine the l2 value.
3120 			 */
3121 			l2nb = (64 - 1) - l2nb;
3122 
3123 			/* check if we need to round up.
3124 			 */
3125 			if (~mask & nb)
3126 				l2nb++;
3127 
3128 			return (l2nb);
3129 		}
3130 	}
3131 	assert(0);
3132 	return 0;		/* fix compiler warning */
3133 }
3134 
3135 
3136 /*
3137  * NAME:	dbAllocBottomUp()
3138  *
3139  * FUNCTION:	alloc the specified block range from the working block
3140  *		allocation map.
3141  *
3142  *		the blocks will be alloc from the working map one dmap
3143  *		at a time.
3144  *
3145  * PARAMETERS:
3146  *	ip	-  pointer to in-core inode;
3147  *	blkno	-  starting block number to be freed.
3148  *	nblocks	-  number of blocks to be freed.
3149  *
3150  * RETURN VALUES:
3151  *	0	- success
3152  *	-EIO	- i/o error
3153  */
dbAllocBottomUp(struct inode * ip,s64 blkno,s64 nblocks)3154 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3155 {
3156 	struct metapage *mp;
3157 	struct dmap *dp;
3158 	int nb, rc;
3159 	s64 lblkno, rem;
3160 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3161 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3162 
3163 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3164 
3165 	/* block to be allocated better be within the mapsize. */
3166 	ASSERT(nblocks <= bmp->db_mapsize - blkno);
3167 
3168 	/*
3169 	 * allocate the blocks a dmap at a time.
3170 	 */
3171 	mp = NULL;
3172 	for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3173 		/* release previous dmap if any */
3174 		if (mp) {
3175 			write_metapage(mp);
3176 		}
3177 
3178 		/* get the buffer for the current dmap. */
3179 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3180 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3181 		if (mp == NULL) {
3182 			IREAD_UNLOCK(ipbmap);
3183 			return -EIO;
3184 		}
3185 		dp = (struct dmap *) mp->data;
3186 
3187 		/* determine the number of blocks to be allocated from
3188 		 * this dmap.
3189 		 */
3190 		nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3191 
3192 		/* allocate the blocks. */
3193 		if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3194 			release_metapage(mp);
3195 			IREAD_UNLOCK(ipbmap);
3196 			return (rc);
3197 		}
3198 	}
3199 
3200 	/* write the last buffer. */
3201 	write_metapage(mp);
3202 
3203 	IREAD_UNLOCK(ipbmap);
3204 
3205 	return (0);
3206 }
3207 
3208 
dbAllocDmapBU(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)3209 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3210 			 int nblocks)
3211 {
3212 	int rc;
3213 	int dbitno, word, rembits, nb, nwords, wbitno, agno;
3214 	s8 oldroot;
3215 	struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3216 
3217 	/* save the current value of the root (i.e. maximum free string)
3218 	 * of the dmap tree.
3219 	 */
3220 	oldroot = tp->stree[ROOT];
3221 
3222 	/* determine the bit number and word within the dmap of the
3223 	 * starting block.
3224 	 */
3225 	dbitno = blkno & (BPERDMAP - 1);
3226 	word = dbitno >> L2DBWORD;
3227 
3228 	/* block range better be within the dmap */
3229 	assert(dbitno + nblocks <= BPERDMAP);
3230 
3231 	/* allocate the bits of the dmap's words corresponding to the block
3232 	 * range. not all bits of the first and last words may be contained
3233 	 * within the block range.  if this is the case, we'll work against
3234 	 * those words (i.e. partial first and/or last) on an individual basis
3235 	 * (a single pass), allocating the bits of interest by hand and
3236 	 * updating the leaf corresponding to the dmap word. a single pass
3237 	 * will be used for all dmap words fully contained within the
3238 	 * specified range.  within this pass, the bits of all fully contained
3239 	 * dmap words will be marked as free in a single shot and the leaves
3240 	 * will be updated. a single leaf may describe the free space of
3241 	 * multiple dmap words, so we may update only a subset of the actual
3242 	 * leaves corresponding to the dmap words of the block range.
3243 	 */
3244 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3245 		/* determine the bit number within the word and
3246 		 * the number of bits within the word.
3247 		 */
3248 		wbitno = dbitno & (DBWORD - 1);
3249 		nb = min(rembits, DBWORD - wbitno);
3250 
3251 		/* check if only part of a word is to be allocated.
3252 		 */
3253 		if (nb < DBWORD) {
3254 			/* allocate (set to 1) the appropriate bits within
3255 			 * this dmap word.
3256 			 */
3257 			dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3258 						      >> wbitno);
3259 
3260 			word++;
3261 		} else {
3262 			/* one or more dmap words are fully contained
3263 			 * within the block range.  determine how many
3264 			 * words and allocate (set to 1) the bits of these
3265 			 * words.
3266 			 */
3267 			nwords = rembits >> L2DBWORD;
3268 			memset(&dp->wmap[word], (int) ONES, nwords * 4);
3269 
3270 			/* determine how many bits */
3271 			nb = nwords << L2DBWORD;
3272 			word += nwords;
3273 		}
3274 	}
3275 
3276 	/* update the free count for this dmap */
3277 	le32_add_cpu(&dp->nfree, -nblocks);
3278 
3279 	/* reconstruct summary tree */
3280 	dbInitDmapTree(dp);
3281 
3282 	BMAP_LOCK(bmp);
3283 
3284 	/* if this allocation group is completely free,
3285 	 * update the highest active allocation group number
3286 	 * if this allocation group is the new max.
3287 	 */
3288 	agno = blkno >> bmp->db_agl2size;
3289 	if (agno > bmp->db_maxag)
3290 		bmp->db_maxag = agno;
3291 
3292 	/* update the free count for the allocation group and map */
3293 	bmp->db_agfree[agno] -= nblocks;
3294 	bmp->db_nfree -= nblocks;
3295 
3296 	BMAP_UNLOCK(bmp);
3297 
3298 	/* if the root has not changed, done. */
3299 	if (tp->stree[ROOT] == oldroot)
3300 		return (0);
3301 
3302 	/* root changed. bubble the change up to the dmap control pages.
3303 	 * if the adjustment of the upper level control pages fails,
3304 	 * backout the bit allocation (thus making everything consistent).
3305 	 */
3306 	if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3307 		dbFreeBits(bmp, dp, blkno, nblocks);
3308 
3309 	return (rc);
3310 }
3311 
3312 
3313 /*
3314  * NAME:	dbExtendFS()
3315  *
3316  * FUNCTION:	extend bmap from blkno for nblocks;
3317  *		dbExtendFS() updates bmap ready for dbAllocBottomUp();
3318  *
3319  * L2
3320  *  |
3321  *   L1---------------------------------L1
3322  *    |					 |
3323  *     L0---------L0---------L0		  L0---------L0---------L0
3324  *      |	   |	      |		   |	      |		 |
3325  *	 d0,...,dn  d0,...,dn  d0,...,dn    d0,...,dn  d0,...,dn  d0,.,dm;
3326  * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3327  *
3328  * <---old---><----------------------------extend----------------------->
3329  */
dbExtendFS(struct inode * ipbmap,s64 blkno,s64 nblocks)3330 int dbExtendFS(struct inode *ipbmap, s64 blkno,	s64 nblocks)
3331 {
3332 	struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3333 	int nbperpage = sbi->nbperpage;
3334 	int i, i0 = true, j, j0 = true, k, n;
3335 	s64 newsize;
3336 	s64 p;
3337 	struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3338 	struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3339 	struct dmap *dp;
3340 	s8 *l0leaf, *l1leaf, *l2leaf;
3341 	struct bmap *bmp = sbi->bmap;
3342 	int agno, l2agsize, oldl2agsize;
3343 	s64 ag_rem;
3344 
3345 	newsize = blkno + nblocks;
3346 
3347 	jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3348 		 (long long) blkno, (long long) nblocks, (long long) newsize);
3349 
3350 	/*
3351 	 *	initialize bmap control page.
3352 	 *
3353 	 * all the data in bmap control page should exclude
3354 	 * the mkfs hidden dmap page.
3355 	 */
3356 
3357 	/* update mapsize */
3358 	bmp->db_mapsize = newsize;
3359 	bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3360 
3361 	/* compute new AG size */
3362 	l2agsize = dbGetL2AGSize(newsize);
3363 	oldl2agsize = bmp->db_agl2size;
3364 
3365 	bmp->db_agl2size = l2agsize;
3366 	bmp->db_agsize = 1 << l2agsize;
3367 
3368 	/* compute new number of AG */
3369 	agno = bmp->db_numag;
3370 	bmp->db_numag = newsize >> l2agsize;
3371 	bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3372 
3373 	/*
3374 	 *	reconfigure db_agfree[]
3375 	 * from old AG configuration to new AG configuration;
3376 	 *
3377 	 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3378 	 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3379 	 * note: new AG size = old AG size * (2**x).
3380 	 */
3381 	if (l2agsize == oldl2agsize)
3382 		goto extend;
3383 	k = 1 << (l2agsize - oldl2agsize);
3384 	ag_rem = bmp->db_agfree[0];	/* save agfree[0] */
3385 	for (i = 0, n = 0; i < agno; n++) {
3386 		bmp->db_agfree[n] = 0;	/* init collection point */
3387 
3388 		/* coalesce contiguous k AGs; */
3389 		for (j = 0; j < k && i < agno; j++, i++) {
3390 			/* merge AGi to AGn */
3391 			bmp->db_agfree[n] += bmp->db_agfree[i];
3392 		}
3393 	}
3394 	bmp->db_agfree[0] += ag_rem;	/* restore agfree[0] */
3395 
3396 	for (; n < MAXAG; n++)
3397 		bmp->db_agfree[n] = 0;
3398 
3399 	/*
3400 	 * update highest active ag number
3401 	 */
3402 
3403 	bmp->db_maxag = bmp->db_maxag / k;
3404 
3405 	/*
3406 	 *	extend bmap
3407 	 *
3408 	 * update bit maps and corresponding level control pages;
3409 	 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3410 	 */
3411       extend:
3412 	/* get L2 page */
3413 	p = BMAPBLKNO + nbperpage;	/* L2 page */
3414 	l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3415 	if (!l2mp) {
3416 		jfs_error(ipbmap->i_sb, "L2 page could not be read\n");
3417 		return -EIO;
3418 	}
3419 	l2dcp = (struct dmapctl *) l2mp->data;
3420 
3421 	/* compute start L1 */
3422 	k = blkno >> L2MAXL1SIZE;
3423 	l2leaf = l2dcp->stree + CTLLEAFIND + k;
3424 	p = BLKTOL1(blkno, sbi->l2nbperpage);	/* L1 page */
3425 
3426 	/*
3427 	 * extend each L1 in L2
3428 	 */
3429 	for (; k < LPERCTL; k++, p += nbperpage) {
3430 		/* get L1 page */
3431 		if (j0) {
3432 			/* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3433 			l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3434 			if (l1mp == NULL)
3435 				goto errout;
3436 			l1dcp = (struct dmapctl *) l1mp->data;
3437 
3438 			/* compute start L0 */
3439 			j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3440 			l1leaf = l1dcp->stree + CTLLEAFIND + j;
3441 			p = BLKTOL0(blkno, sbi->l2nbperpage);
3442 			j0 = false;
3443 		} else {
3444 			/* assign/init L1 page */
3445 			l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3446 			if (l1mp == NULL)
3447 				goto errout;
3448 
3449 			l1dcp = (struct dmapctl *) l1mp->data;
3450 
3451 			/* compute start L0 */
3452 			j = 0;
3453 			l1leaf = l1dcp->stree + CTLLEAFIND;
3454 			p += nbperpage;	/* 1st L0 of L1.k */
3455 		}
3456 
3457 		/*
3458 		 * extend each L0 in L1
3459 		 */
3460 		for (; j < LPERCTL; j++) {
3461 			/* get L0 page */
3462 			if (i0) {
3463 				/* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3464 
3465 				l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3466 				if (l0mp == NULL)
3467 					goto errout;
3468 				l0dcp = (struct dmapctl *) l0mp->data;
3469 
3470 				/* compute start dmap */
3471 				i = (blkno & (MAXL0SIZE - 1)) >>
3472 				    L2BPERDMAP;
3473 				l0leaf = l0dcp->stree + CTLLEAFIND + i;
3474 				p = BLKTODMAP(blkno,
3475 					      sbi->l2nbperpage);
3476 				i0 = false;
3477 			} else {
3478 				/* assign/init L0 page */
3479 				l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3480 				if (l0mp == NULL)
3481 					goto errout;
3482 
3483 				l0dcp = (struct dmapctl *) l0mp->data;
3484 
3485 				/* compute start dmap */
3486 				i = 0;
3487 				l0leaf = l0dcp->stree + CTLLEAFIND;
3488 				p += nbperpage;	/* 1st dmap of L0.j */
3489 			}
3490 
3491 			/*
3492 			 * extend each dmap in L0
3493 			 */
3494 			for (; i < LPERCTL; i++) {
3495 				/*
3496 				 * reconstruct the dmap page, and
3497 				 * initialize corresponding parent L0 leaf
3498 				 */
3499 				if ((n = blkno & (BPERDMAP - 1))) {
3500 					/* read in dmap page: */
3501 					mp = read_metapage(ipbmap, p,
3502 							   PSIZE, 0);
3503 					if (mp == NULL)
3504 						goto errout;
3505 					n = min(nblocks, (s64)BPERDMAP - n);
3506 				} else {
3507 					/* assign/init dmap page */
3508 					mp = read_metapage(ipbmap, p,
3509 							   PSIZE, 0);
3510 					if (mp == NULL)
3511 						goto errout;
3512 
3513 					n = min_t(s64, nblocks, BPERDMAP);
3514 				}
3515 
3516 				dp = (struct dmap *) mp->data;
3517 				*l0leaf = dbInitDmap(dp, blkno, n);
3518 
3519 				bmp->db_nfree += n;
3520 				agno = le64_to_cpu(dp->start) >> l2agsize;
3521 				bmp->db_agfree[agno] += n;
3522 
3523 				write_metapage(mp);
3524 
3525 				l0leaf++;
3526 				p += nbperpage;
3527 
3528 				blkno += n;
3529 				nblocks -= n;
3530 				if (nblocks == 0)
3531 					break;
3532 			}	/* for each dmap in a L0 */
3533 
3534 			/*
3535 			 * build current L0 page from its leaves, and
3536 			 * initialize corresponding parent L1 leaf
3537 			 */
3538 			*l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3539 			write_metapage(l0mp);
3540 			l0mp = NULL;
3541 
3542 			if (nblocks)
3543 				l1leaf++;	/* continue for next L0 */
3544 			else {
3545 				/* more than 1 L0 ? */
3546 				if (j > 0)
3547 					break;	/* build L1 page */
3548 				else {
3549 					/* summarize in global bmap page */
3550 					bmp->db_maxfreebud = *l1leaf;
3551 					release_metapage(l1mp);
3552 					release_metapage(l2mp);
3553 					goto finalize;
3554 				}
3555 			}
3556 		}		/* for each L0 in a L1 */
3557 
3558 		/*
3559 		 * build current L1 page from its leaves, and
3560 		 * initialize corresponding parent L2 leaf
3561 		 */
3562 		*l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3563 		write_metapage(l1mp);
3564 		l1mp = NULL;
3565 
3566 		if (nblocks)
3567 			l2leaf++;	/* continue for next L1 */
3568 		else {
3569 			/* more than 1 L1 ? */
3570 			if (k > 0)
3571 				break;	/* build L2 page */
3572 			else {
3573 				/* summarize in global bmap page */
3574 				bmp->db_maxfreebud = *l2leaf;
3575 				release_metapage(l2mp);
3576 				goto finalize;
3577 			}
3578 		}
3579 	}			/* for each L1 in a L2 */
3580 
3581 	jfs_error(ipbmap->i_sb, "function has not returned as expected\n");
3582 errout:
3583 	if (l0mp)
3584 		release_metapage(l0mp);
3585 	if (l1mp)
3586 		release_metapage(l1mp);
3587 	release_metapage(l2mp);
3588 	return -EIO;
3589 
3590 	/*
3591 	 *	finalize bmap control page
3592 	 */
3593 finalize:
3594 
3595 	return 0;
3596 }
3597 
3598 
3599 /*
3600  *	dbFinalizeBmap()
3601  */
dbFinalizeBmap(struct inode * ipbmap)3602 void dbFinalizeBmap(struct inode *ipbmap)
3603 {
3604 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3605 	int actags, inactags, l2nl;
3606 	s64 ag_rem, actfree, inactfree, avgfree;
3607 	int i, n;
3608 
3609 	/*
3610 	 *	finalize bmap control page
3611 	 */
3612 //finalize:
3613 	/*
3614 	 * compute db_agpref: preferred ag to allocate from
3615 	 * (the leftmost ag with average free space in it);
3616 	 */
3617 //agpref:
3618 	/* get the number of active ags and inactive ags */
3619 	actags = bmp->db_maxag + 1;
3620 	inactags = bmp->db_numag - actags;
3621 	ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1);	/* ??? */
3622 
3623 	/* determine how many blocks are in the inactive allocation
3624 	 * groups. in doing this, we must account for the fact that
3625 	 * the rightmost group might be a partial group (i.e. file
3626 	 * system size is not a multiple of the group size).
3627 	 */
3628 	inactfree = (inactags && ag_rem) ?
3629 	    ((inactags - 1) << bmp->db_agl2size) + ag_rem
3630 	    : inactags << bmp->db_agl2size;
3631 
3632 	/* determine how many free blocks are in the active
3633 	 * allocation groups plus the average number of free blocks
3634 	 * within the active ags.
3635 	 */
3636 	actfree = bmp->db_nfree - inactfree;
3637 	avgfree = (u32) actfree / (u32) actags;
3638 
3639 	/* if the preferred allocation group has not average free space.
3640 	 * re-establish the preferred group as the leftmost
3641 	 * group with average free space.
3642 	 */
3643 	if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3644 		for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3645 		     bmp->db_agpref++) {
3646 			if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3647 				break;
3648 		}
3649 		if (bmp->db_agpref >= bmp->db_numag) {
3650 			jfs_error(ipbmap->i_sb,
3651 				  "cannot find ag with average freespace\n");
3652 		}
3653 	}
3654 
3655 	/*
3656 	 * compute db_aglevel, db_agheight, db_width, db_agstart:
3657 	 * an ag is covered in aglevel dmapctl summary tree,
3658 	 * at agheight level height (from leaf) with agwidth number of nodes
3659 	 * each, which starts at agstart index node of the smmary tree node
3660 	 * array;
3661 	 */
3662 	bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3663 	l2nl =
3664 	    bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3665 	bmp->db_agheight = l2nl >> 1;
3666 	bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3667 	for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3668 	     i--) {
3669 		bmp->db_agstart += n;
3670 		n <<= 2;
3671 	}
3672 
3673 }
3674 
3675 
3676 /*
3677  * NAME:	dbInitDmap()/ujfs_idmap_page()
3678  *
3679  * FUNCTION:	initialize working/persistent bitmap of the dmap page
3680  *		for the specified number of blocks:
3681  *
3682  *		at entry, the bitmaps had been initialized as free (ZEROS);
3683  *		The number of blocks will only account for the actually
3684  *		existing blocks. Blocks which don't actually exist in
3685  *		the aggregate will be marked as allocated (ONES);
3686  *
3687  * PARAMETERS:
3688  *	dp	- pointer to page of map
3689  *	nblocks	- number of blocks this page
3690  *
3691  * RETURNS: NONE
3692  */
dbInitDmap(struct dmap * dp,s64 Blkno,int nblocks)3693 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3694 {
3695 	int blkno, w, b, r, nw, nb, i;
3696 
3697 	/* starting block number within the dmap */
3698 	blkno = Blkno & (BPERDMAP - 1);
3699 
3700 	if (blkno == 0) {
3701 		dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3702 		dp->start = cpu_to_le64(Blkno);
3703 
3704 		if (nblocks == BPERDMAP) {
3705 			memset(&dp->wmap[0], 0, LPERDMAP * 4);
3706 			memset(&dp->pmap[0], 0, LPERDMAP * 4);
3707 			goto initTree;
3708 		}
3709 	} else {
3710 		le32_add_cpu(&dp->nblocks, nblocks);
3711 		le32_add_cpu(&dp->nfree, nblocks);
3712 	}
3713 
3714 	/* word number containing start block number */
3715 	w = blkno >> L2DBWORD;
3716 
3717 	/*
3718 	 * free the bits corresponding to the block range (ZEROS):
3719 	 * note: not all bits of the first and last words may be contained
3720 	 * within the block range.
3721 	 */
3722 	for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3723 		/* number of bits preceding range to be freed in the word */
3724 		b = blkno & (DBWORD - 1);
3725 		/* number of bits to free in the word */
3726 		nb = min(r, DBWORD - b);
3727 
3728 		/* is partial word to be freed ? */
3729 		if (nb < DBWORD) {
3730 			/* free (set to 0) from the bitmap word */
3731 			dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3732 						     >> b));
3733 			dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3734 						     >> b));
3735 
3736 			/* skip the word freed */
3737 			w++;
3738 		} else {
3739 			/* free (set to 0) contiguous bitmap words */
3740 			nw = r >> L2DBWORD;
3741 			memset(&dp->wmap[w], 0, nw * 4);
3742 			memset(&dp->pmap[w], 0, nw * 4);
3743 
3744 			/* skip the words freed */
3745 			nb = nw << L2DBWORD;
3746 			w += nw;
3747 		}
3748 	}
3749 
3750 	/*
3751 	 * mark bits following the range to be freed (non-existing
3752 	 * blocks) as allocated (ONES)
3753 	 */
3754 
3755 	if (blkno == BPERDMAP)
3756 		goto initTree;
3757 
3758 	/* the first word beyond the end of existing blocks */
3759 	w = blkno >> L2DBWORD;
3760 
3761 	/* does nblocks fall on a 32-bit boundary ? */
3762 	b = blkno & (DBWORD - 1);
3763 	if (b) {
3764 		/* mark a partial word allocated */
3765 		dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3766 		w++;
3767 	}
3768 
3769 	/* set the rest of the words in the page to allocated (ONES) */
3770 	for (i = w; i < LPERDMAP; i++)
3771 		dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3772 
3773 	/*
3774 	 * init tree
3775 	 */
3776       initTree:
3777 	return (dbInitDmapTree(dp));
3778 }
3779 
3780 
3781 /*
3782  * NAME:	dbInitDmapTree()/ujfs_complete_dmap()
3783  *
3784  * FUNCTION:	initialize summary tree of the specified dmap:
3785  *
3786  *		at entry, bitmap of the dmap has been initialized;
3787  *
3788  * PARAMETERS:
3789  *	dp	- dmap to complete
3790  *	blkno	- starting block number for this dmap
3791  *	treemax	- will be filled in with max free for this dmap
3792  *
3793  * RETURNS:	max free string at the root of the tree
3794  */
dbInitDmapTree(struct dmap * dp)3795 static int dbInitDmapTree(struct dmap * dp)
3796 {
3797 	struct dmaptree *tp;
3798 	s8 *cp;
3799 	int i;
3800 
3801 	/* init fixed info of tree */
3802 	tp = &dp->tree;
3803 	tp->nleafs = cpu_to_le32(LPERDMAP);
3804 	tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3805 	tp->leafidx = cpu_to_le32(LEAFIND);
3806 	tp->height = cpu_to_le32(4);
3807 	tp->budmin = BUDMIN;
3808 
3809 	/* init each leaf from corresponding wmap word:
3810 	 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3811 	 * bitmap word are allocated.
3812 	 */
3813 	cp = tp->stree + le32_to_cpu(tp->leafidx);
3814 	for (i = 0; i < LPERDMAP; i++)
3815 		*cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3816 
3817 	/* build the dmap's binary buddy summary tree */
3818 	return (dbInitTree(tp));
3819 }
3820 
3821 
3822 /*
3823  * NAME:	dbInitTree()/ujfs_adjtree()
3824  *
3825  * FUNCTION:	initialize binary buddy summary tree of a dmap or dmapctl.
3826  *
3827  *		at entry, the leaves of the tree has been initialized
3828  *		from corresponding bitmap word or root of summary tree
3829  *		of the child control page;
3830  *		configure binary buddy system at the leaf level, then
3831  *		bubble up the values of the leaf nodes up the tree.
3832  *
3833  * PARAMETERS:
3834  *	cp	- Pointer to the root of the tree
3835  *	l2leaves- Number of leaf nodes as a power of 2
3836  *	l2min	- Number of blocks that can be covered by a leaf
3837  *		  as a power of 2
3838  *
3839  * RETURNS: max free string at the root of the tree
3840  */
dbInitTree(struct dmaptree * dtp)3841 static int dbInitTree(struct dmaptree * dtp)
3842 {
3843 	int l2max, l2free, bsize, nextb, i;
3844 	int child, parent, nparent;
3845 	s8 *tp, *cp, *cp1;
3846 
3847 	tp = dtp->stree;
3848 
3849 	/* Determine the maximum free string possible for the leaves */
3850 	l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3851 
3852 	/*
3853 	 * configure the leaf levevl into binary buddy system
3854 	 *
3855 	 * Try to combine buddies starting with a buddy size of 1
3856 	 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3857 	 * can be combined if both buddies have a maximum free of l2min;
3858 	 * the combination will result in the left-most buddy leaf having
3859 	 * a maximum free of l2min+1.
3860 	 * After processing all buddies for a given size, process buddies
3861 	 * at the next higher buddy size (i.e. current size * 2) and
3862 	 * the next maximum free (current free + 1).
3863 	 * This continues until the maximum possible buddy combination
3864 	 * yields maximum free.
3865 	 */
3866 	for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3867 	     l2free++, bsize = nextb) {
3868 		/* get next buddy size == current buddy pair size */
3869 		nextb = bsize << 1;
3870 
3871 		/* scan each adjacent buddy pair at current buddy size */
3872 		for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3873 		     i < le32_to_cpu(dtp->nleafs);
3874 		     i += nextb, cp += nextb) {
3875 			/* coalesce if both adjacent buddies are max free */
3876 			if (*cp == l2free && *(cp + bsize) == l2free) {
3877 				*cp = l2free + 1;	/* left take right */
3878 				*(cp + bsize) = -1;	/* right give left */
3879 			}
3880 		}
3881 	}
3882 
3883 	/*
3884 	 * bubble summary information of leaves up the tree.
3885 	 *
3886 	 * Starting at the leaf node level, the four nodes described by
3887 	 * the higher level parent node are compared for a maximum free and
3888 	 * this maximum becomes the value of the parent node.
3889 	 * when all lower level nodes are processed in this fashion then
3890 	 * move up to the next level (parent becomes a lower level node) and
3891 	 * continue the process for that level.
3892 	 */
3893 	for (child = le32_to_cpu(dtp->leafidx),
3894 	     nparent = le32_to_cpu(dtp->nleafs) >> 2;
3895 	     nparent > 0; nparent >>= 2, child = parent) {
3896 		/* get index of 1st node of parent level */
3897 		parent = (child - 1) >> 2;
3898 
3899 		/* set the value of the parent node as the maximum
3900 		 * of the four nodes of the current level.
3901 		 */
3902 		for (i = 0, cp = tp + child, cp1 = tp + parent;
3903 		     i < nparent; i++, cp += 4, cp1++)
3904 			*cp1 = TREEMAX(cp);
3905 	}
3906 
3907 	return (*tp);
3908 }
3909 
3910 
3911 /*
3912  *	dbInitDmapCtl()
3913  *
3914  * function: initialize dmapctl page
3915  */
dbInitDmapCtl(struct dmapctl * dcp,int level,int i)3916 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3917 {				/* start leaf index not covered by range */
3918 	s8 *cp;
3919 
3920 	dcp->nleafs = cpu_to_le32(LPERCTL);
3921 	dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3922 	dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3923 	dcp->height = cpu_to_le32(5);
3924 	dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3925 
3926 	/*
3927 	 * initialize the leaves of current level that were not covered
3928 	 * by the specified input block range (i.e. the leaves have no
3929 	 * low level dmapctl or dmap).
3930 	 */
3931 	cp = &dcp->stree[CTLLEAFIND + i];
3932 	for (; i < LPERCTL; i++)
3933 		*cp++ = NOFREE;
3934 
3935 	/* build the dmap's binary buddy summary tree */
3936 	return (dbInitTree((struct dmaptree *) dcp));
3937 }
3938 
3939 
3940 /*
3941  * NAME:	dbGetL2AGSize()/ujfs_getagl2size()
3942  *
3943  * FUNCTION:	Determine log2(allocation group size) from aggregate size
3944  *
3945  * PARAMETERS:
3946  *	nblocks	- Number of blocks in aggregate
3947  *
3948  * RETURNS: log2(allocation group size) in aggregate blocks
3949  */
dbGetL2AGSize(s64 nblocks)3950 static int dbGetL2AGSize(s64 nblocks)
3951 {
3952 	s64 sz;
3953 	s64 m;
3954 	int l2sz;
3955 
3956 	if (nblocks < BPERDMAP * MAXAG)
3957 		return (L2BPERDMAP);
3958 
3959 	/* round up aggregate size to power of 2 */
3960 	m = ((u64) 1 << (64 - 1));
3961 	for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3962 		if (m & nblocks)
3963 			break;
3964 	}
3965 
3966 	sz = (s64) 1 << l2sz;
3967 	if (sz < nblocks)
3968 		l2sz += 1;
3969 
3970 	/* agsize = roundupSize/max_number_of_ag */
3971 	return (l2sz - L2MAXAG);
3972 }
3973 
3974 
3975 /*
3976  * NAME:	dbMapFileSizeToMapSize()
3977  *
3978  * FUNCTION:	compute number of blocks the block allocation map file
3979  *		can cover from the map file size;
3980  *
3981  * RETURNS:	Number of blocks which can be covered by this block map file;
3982  */
3983 
3984 /*
3985  * maximum number of map pages at each level including control pages
3986  */
3987 #define MAXL0PAGES	(1 + LPERCTL)
3988 #define MAXL1PAGES	(1 + LPERCTL * MAXL0PAGES)
3989 
3990 /*
3991  * convert number of map pages to the zero origin top dmapctl level
3992  */
3993 #define BMAPPGTOLEV(npages)	\
3994 	(((npages) <= 3 + MAXL0PAGES) ? 0 : \
3995 	 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
3996 
dbMapFileSizeToMapSize(struct inode * ipbmap)3997 s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3998 {
3999 	struct super_block *sb = ipbmap->i_sb;
4000 	s64 nblocks;
4001 	s64 npages, ndmaps;
4002 	int level, i;
4003 	int complete, factor;
4004 
4005 	nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
4006 	npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
4007 	level = BMAPPGTOLEV(npages);
4008 
4009 	/* At each level, accumulate the number of dmap pages covered by
4010 	 * the number of full child levels below it;
4011 	 * repeat for the last incomplete child level.
4012 	 */
4013 	ndmaps = 0;
4014 	npages--;		/* skip the first global control page */
4015 	/* skip higher level control pages above top level covered by map */
4016 	npages -= (2 - level);
4017 	npages--;		/* skip top level's control page */
4018 	for (i = level; i >= 0; i--) {
4019 		factor =
4020 		    (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
4021 		complete = (u32) npages / factor;
4022 		ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
4023 				      ((i == 1) ? LPERCTL : 1));
4024 
4025 		/* pages in last/incomplete child */
4026 		npages = (u32) npages % factor;
4027 		/* skip incomplete child's level control page */
4028 		npages--;
4029 	}
4030 
4031 	/* convert the number of dmaps into the number of blocks
4032 	 * which can be covered by the dmaps;
4033 	 */
4034 	nblocks = ndmaps << L2BPERDMAP;
4035 
4036 	return (nblocks);
4037 }
4038