Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[wrt350n-kernel.git] / fs / jfs / jfs_dmap.c
blobe1985066b1c63273cf5bf568ea6f9a417abb0a7a
1 /*
2 * Copyright (C) International Business Machines Corp., 2000-2004
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 #include <linux/fs.h>
20 #include "jfs_incore.h"
21 #include "jfs_superblock.h"
22 #include "jfs_dmap.h"
23 #include "jfs_imap.h"
24 #include "jfs_lock.h"
25 #include "jfs_metapage.h"
26 #include "jfs_debug.h"
29 * SERIALIZATION of the Block Allocation Map.
31 * the working state of the block allocation map is accessed in
32 * two directions:
34 * 1) allocation and free requests that start at the dmap
35 * level and move up through the dmap control pages (i.e.
36 * the vast majority of requests).
38 * 2) allocation requests that start at dmap control page
39 * level and work down towards the dmaps.
41 * the serialization scheme used here is as follows.
43 * requests which start at the bottom are serialized against each
44 * other through buffers and each requests holds onto its buffers
45 * as it works it way up from a single dmap to the required level
46 * of dmap control page.
47 * requests that start at the top are serialized against each other
48 * and request that start from the bottom by the multiple read/single
49 * write inode lock of the bmap inode. requests starting at the top
50 * take this lock in write mode while request starting at the bottom
51 * take the lock in read mode. a single top-down request may proceed
52 * exclusively while multiple bottoms-up requests may proceed
53 * simultaneously (under the protection of busy buffers).
55 * in addition to information found in dmaps and dmap control pages,
56 * the working state of the block allocation map also includes read/
57 * write information maintained in the bmap descriptor (i.e. total
58 * free block count, allocation group level free block counts).
59 * a single exclusive lock (BMAP_LOCK) is used to guard this information
60 * in the face of multiple-bottoms up requests.
61 * (lock ordering: IREAD_LOCK, BMAP_LOCK);
63 * accesses to the persistent state of the block allocation map (limited
64 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
67 #define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
68 #define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
69 #define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
72 * forward references
74 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
75 int nblocks);
76 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
77 static int dbBackSplit(dmtree_t * tp, int leafno);
78 static int dbJoin(dmtree_t * tp, int leafno, int newval);
79 static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
80 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
81 int level);
82 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
83 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
84 int nblocks);
85 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
86 int nblocks,
87 int l2nb, s64 * results);
88 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
89 int nblocks);
90 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
91 int l2nb,
92 s64 * results);
93 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
94 s64 * results);
95 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
96 s64 * results);
97 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
98 static int dbFindBits(u32 word, int l2nb);
99 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
100 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
101 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
102 int nblocks);
103 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
104 int nblocks);
105 static int dbMaxBud(u8 * cp);
106 s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
107 static int blkstol2(s64 nb);
109 static int cntlz(u32 value);
110 static int cnttz(u32 word);
112 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
113 int nblocks);
114 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
115 static int dbInitDmapTree(struct dmap * dp);
116 static int dbInitTree(struct dmaptree * dtp);
117 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
118 static int dbGetL2AGSize(s64 nblocks);
121 * buddy table
123 * table used for determining buddy sizes within characters of
124 * dmap bitmap words. the characters themselves serve as indexes
125 * into the table, with the table elements yielding the maximum
126 * binary buddy of free bits within the character.
128 static const s8 budtab[256] = {
129 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
130 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
131 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
132 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
133 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
134 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
135 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
136 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
137 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
138 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
139 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
140 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
141 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
142 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
143 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
144 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
149 * NAME: dbMount()
151 * FUNCTION: initializate the block allocation map.
153 * memory is allocated for the in-core bmap descriptor and
154 * the in-core descriptor is initialized from disk.
156 * PARAMETERS:
157 * ipbmap - pointer to in-core inode for the block map.
159 * RETURN VALUES:
160 * 0 - success
161 * -ENOMEM - insufficient memory
162 * -EIO - i/o error
164 int dbMount(struct inode *ipbmap)
166 struct bmap *bmp;
167 struct dbmap_disk *dbmp_le;
168 struct metapage *mp;
169 int i;
172 * allocate/initialize the in-memory bmap descriptor
174 /* allocate memory for the in-memory bmap descriptor */
175 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
176 if (bmp == NULL)
177 return -ENOMEM;
179 /* read the on-disk bmap descriptor. */
180 mp = read_metapage(ipbmap,
181 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
182 PSIZE, 0);
183 if (mp == NULL) {
184 kfree(bmp);
185 return -EIO;
188 /* copy the on-disk bmap descriptor to its in-memory version. */
189 dbmp_le = (struct dbmap_disk *) mp->data;
190 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
191 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
192 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
193 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
194 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
195 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
196 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
197 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
198 bmp->db_agheigth = le32_to_cpu(dbmp_le->dn_agheigth);
199 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
200 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
201 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
202 for (i = 0; i < MAXAG; i++)
203 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
204 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
205 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
207 /* release the buffer. */
208 release_metapage(mp);
210 /* bind the bmap inode and the bmap descriptor to each other. */
211 bmp->db_ipbmap = ipbmap;
212 JFS_SBI(ipbmap->i_sb)->bmap = bmp;
214 memset(bmp->db_active, 0, sizeof(bmp->db_active));
217 * allocate/initialize the bmap lock
219 BMAP_LOCK_INIT(bmp);
221 return (0);
226 * NAME: dbUnmount()
228 * FUNCTION: terminate the block allocation map in preparation for
229 * file system unmount.
231 * the in-core bmap descriptor is written to disk and
232 * the memory for this descriptor is freed.
234 * PARAMETERS:
235 * ipbmap - pointer to in-core inode for the block map.
237 * RETURN VALUES:
238 * 0 - success
239 * -EIO - i/o error
241 int dbUnmount(struct inode *ipbmap, int mounterror)
243 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
245 if (!(mounterror || isReadOnly(ipbmap)))
246 dbSync(ipbmap);
249 * Invalidate the page cache buffers
251 truncate_inode_pages(ipbmap->i_mapping, 0);
253 /* free the memory for the in-memory bmap. */
254 kfree(bmp);
256 return (0);
260 * dbSync()
262 int dbSync(struct inode *ipbmap)
264 struct dbmap_disk *dbmp_le;
265 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
266 struct metapage *mp;
267 int i;
270 * write bmap global control page
272 /* get the buffer for the on-disk bmap descriptor. */
273 mp = read_metapage(ipbmap,
274 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
275 PSIZE, 0);
276 if (mp == NULL) {
277 jfs_err("dbSync: read_metapage failed!");
278 return -EIO;
280 /* copy the in-memory version of the bmap to the on-disk version */
281 dbmp_le = (struct dbmap_disk *) mp->data;
282 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
283 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
284 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
285 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
286 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
287 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
288 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
289 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
290 dbmp_le->dn_agheigth = cpu_to_le32(bmp->db_agheigth);
291 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
292 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
293 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
294 for (i = 0; i < MAXAG; i++)
295 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
296 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
297 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
299 /* write the buffer */
300 write_metapage(mp);
303 * write out dirty pages of bmap
305 filemap_write_and_wait(ipbmap->i_mapping);
307 diWriteSpecial(ipbmap, 0);
309 return (0);
314 * NAME: dbFree()
316 * FUNCTION: free the specified block range from the working block
317 * allocation map.
319 * the blocks will be free from the working map one dmap
320 * at a time.
322 * PARAMETERS:
323 * ip - pointer to in-core inode;
324 * blkno - starting block number to be freed.
325 * nblocks - number of blocks to be freed.
327 * RETURN VALUES:
328 * 0 - success
329 * -EIO - i/o error
331 int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
333 struct metapage *mp;
334 struct dmap *dp;
335 int nb, rc;
336 s64 lblkno, rem;
337 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
338 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
340 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
342 /* block to be freed better be within the mapsize. */
343 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
344 IREAD_UNLOCK(ipbmap);
345 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
346 (unsigned long long) blkno,
347 (unsigned long long) nblocks);
348 jfs_error(ip->i_sb,
349 "dbFree: block to be freed is outside the map");
350 return -EIO;
354 * free the blocks a dmap at a time.
356 mp = NULL;
357 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
358 /* release previous dmap if any */
359 if (mp) {
360 write_metapage(mp);
363 /* get the buffer for the current dmap. */
364 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
365 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
366 if (mp == NULL) {
367 IREAD_UNLOCK(ipbmap);
368 return -EIO;
370 dp = (struct dmap *) mp->data;
372 /* determine the number of blocks to be freed from
373 * this dmap.
375 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
377 /* free the blocks. */
378 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
379 jfs_error(ip->i_sb, "dbFree: error in block map\n");
380 release_metapage(mp);
381 IREAD_UNLOCK(ipbmap);
382 return (rc);
386 /* write the last buffer. */
387 write_metapage(mp);
389 IREAD_UNLOCK(ipbmap);
391 return (0);
396 * NAME: dbUpdatePMap()
398 * FUNCTION: update the allocation state (free or allocate) of the
399 * specified block range in the persistent block allocation map.
401 * the blocks will be updated in the persistent map one
402 * dmap at a time.
404 * PARAMETERS:
405 * ipbmap - pointer to in-core inode for the block map.
406 * free - 'true' if block range is to be freed from the persistent
407 * map; 'false' if it is to be allocated.
408 * blkno - starting block number of the range.
409 * nblocks - number of contiguous blocks in the range.
410 * tblk - transaction block;
412 * RETURN VALUES:
413 * 0 - success
414 * -EIO - i/o error
417 dbUpdatePMap(struct inode *ipbmap,
418 int free, s64 blkno, s64 nblocks, struct tblock * tblk)
420 int nblks, dbitno, wbitno, rbits;
421 int word, nbits, nwords;
422 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
423 s64 lblkno, rem, lastlblkno;
424 u32 mask;
425 struct dmap *dp;
426 struct metapage *mp;
427 struct jfs_log *log;
428 int lsn, difft, diffp;
429 unsigned long flags;
431 /* the blocks better be within the mapsize. */
432 if (blkno + nblocks > bmp->db_mapsize) {
433 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
434 (unsigned long long) blkno,
435 (unsigned long long) nblocks);
436 jfs_error(ipbmap->i_sb,
437 "dbUpdatePMap: blocks are outside the map");
438 return -EIO;
441 /* compute delta of transaction lsn from log syncpt */
442 lsn = tblk->lsn;
443 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
444 logdiff(difft, lsn, log);
447 * update the block state a dmap at a time.
449 mp = NULL;
450 lastlblkno = 0;
451 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
452 /* get the buffer for the current dmap. */
453 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
454 if (lblkno != lastlblkno) {
455 if (mp) {
456 write_metapage(mp);
459 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
461 if (mp == NULL)
462 return -EIO;
463 metapage_wait_for_io(mp);
465 dp = (struct dmap *) mp->data;
467 /* determine the bit number and word within the dmap of
468 * the starting block. also determine how many blocks
469 * are to be updated within this dmap.
471 dbitno = blkno & (BPERDMAP - 1);
472 word = dbitno >> L2DBWORD;
473 nblks = min(rem, (s64)BPERDMAP - dbitno);
475 /* update the bits of the dmap words. the first and last
476 * words may only have a subset of their bits updated. if
477 * this is the case, we'll work against that word (i.e.
478 * partial first and/or last) only in a single pass. a
479 * single pass will also be used to update all words that
480 * are to have all their bits updated.
482 for (rbits = nblks; rbits > 0;
483 rbits -= nbits, dbitno += nbits) {
484 /* determine the bit number within the word and
485 * the number of bits within the word.
487 wbitno = dbitno & (DBWORD - 1);
488 nbits = min(rbits, DBWORD - wbitno);
490 /* check if only part of the word is to be updated. */
491 if (nbits < DBWORD) {
492 /* update (free or allocate) the bits
493 * in this word.
495 mask =
496 (ONES << (DBWORD - nbits) >> wbitno);
497 if (free)
498 dp->pmap[word] &=
499 cpu_to_le32(~mask);
500 else
501 dp->pmap[word] |=
502 cpu_to_le32(mask);
504 word += 1;
505 } else {
506 /* one or more words are to have all
507 * their bits updated. determine how
508 * many words and how many bits.
510 nwords = rbits >> L2DBWORD;
511 nbits = nwords << L2DBWORD;
513 /* update (free or allocate) the bits
514 * in these words.
516 if (free)
517 memset(&dp->pmap[word], 0,
518 nwords * 4);
519 else
520 memset(&dp->pmap[word], (int) ONES,
521 nwords * 4);
523 word += nwords;
528 * update dmap lsn
530 if (lblkno == lastlblkno)
531 continue;
533 lastlblkno = lblkno;
535 LOGSYNC_LOCK(log, flags);
536 if (mp->lsn != 0) {
537 /* inherit older/smaller lsn */
538 logdiff(diffp, mp->lsn, log);
539 if (difft < diffp) {
540 mp->lsn = lsn;
542 /* move bp after tblock in logsync list */
543 list_move(&mp->synclist, &tblk->synclist);
546 /* inherit younger/larger clsn */
547 logdiff(difft, tblk->clsn, log);
548 logdiff(diffp, mp->clsn, log);
549 if (difft > diffp)
550 mp->clsn = tblk->clsn;
551 } else {
552 mp->log = log;
553 mp->lsn = lsn;
555 /* insert bp after tblock in logsync list */
556 log->count++;
557 list_add(&mp->synclist, &tblk->synclist);
559 mp->clsn = tblk->clsn;
561 LOGSYNC_UNLOCK(log, flags);
564 /* write the last buffer. */
565 if (mp) {
566 write_metapage(mp);
569 return (0);
574 * NAME: dbNextAG()
576 * FUNCTION: find the preferred allocation group for new allocations.
578 * Within the allocation groups, we maintain a preferred
579 * allocation group which consists of a group with at least
580 * average free space. It is the preferred group that we target
581 * new inode allocation towards. The tie-in between inode
582 * allocation and block allocation occurs as we allocate the
583 * first (data) block of an inode and specify the inode (block)
584 * as the allocation hint for this block.
586 * We try to avoid having more than one open file growing in
587 * an allocation group, as this will lead to fragmentation.
588 * This differs from the old OS/2 method of trying to keep
589 * empty ags around for large allocations.
591 * PARAMETERS:
592 * ipbmap - pointer to in-core inode for the block map.
594 * RETURN VALUES:
595 * the preferred allocation group number.
597 int dbNextAG(struct inode *ipbmap)
599 s64 avgfree;
600 int agpref;
601 s64 hwm = 0;
602 int i;
603 int next_best = -1;
604 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
606 BMAP_LOCK(bmp);
608 /* determine the average number of free blocks within the ags. */
609 avgfree = (u32)bmp->db_nfree / bmp->db_numag;
612 * if the current preferred ag does not have an active allocator
613 * and has at least average freespace, return it
615 agpref = bmp->db_agpref;
616 if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
617 (bmp->db_agfree[agpref] >= avgfree))
618 goto unlock;
620 /* From the last preferred ag, find the next one with at least
621 * average free space.
623 for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
624 if (agpref == bmp->db_numag)
625 agpref = 0;
627 if (atomic_read(&bmp->db_active[agpref]))
628 /* open file is currently growing in this ag */
629 continue;
630 if (bmp->db_agfree[agpref] >= avgfree) {
631 /* Return this one */
632 bmp->db_agpref = agpref;
633 goto unlock;
634 } else if (bmp->db_agfree[agpref] > hwm) {
635 /* Less than avg. freespace, but best so far */
636 hwm = bmp->db_agfree[agpref];
637 next_best = agpref;
642 * If no inactive ag was found with average freespace, use the
643 * next best
645 if (next_best != -1)
646 bmp->db_agpref = next_best;
647 /* else leave db_agpref unchanged */
648 unlock:
649 BMAP_UNLOCK(bmp);
651 /* return the preferred group.
653 return (bmp->db_agpref);
657 * NAME: dbAlloc()
659 * FUNCTION: attempt to allocate a specified number of contiguous free
660 * blocks from the working allocation block map.
662 * the block allocation policy uses hints and a multi-step
663 * approach.
665 * for allocation requests smaller than the number of blocks
666 * per dmap, we first try to allocate the new blocks
667 * immediately following the hint. if these blocks are not
668 * available, we try to allocate blocks near the hint. if
669 * no blocks near the hint are available, we next try to
670 * allocate within the same dmap as contains the hint.
672 * if no blocks are available in the dmap or the allocation
673 * request is larger than the dmap size, we try to allocate
674 * within the same allocation group as contains the hint. if
675 * this does not succeed, we finally try to allocate anywhere
676 * within the aggregate.
678 * we also try to allocate anywhere within the aggregate for
679 * for allocation requests larger than the allocation group
680 * size or requests that specify no hint value.
682 * PARAMETERS:
683 * ip - pointer to in-core inode;
684 * hint - allocation hint.
685 * nblocks - number of contiguous blocks in the range.
686 * results - on successful return, set to the starting block number
687 * of the newly allocated contiguous range.
689 * RETURN VALUES:
690 * 0 - success
691 * -ENOSPC - insufficient disk resources
692 * -EIO - i/o error
694 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
696 int rc, agno;
697 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
698 struct bmap *bmp;
699 struct metapage *mp;
700 s64 lblkno, blkno;
701 struct dmap *dp;
702 int l2nb;
703 s64 mapSize;
704 int writers;
706 /* assert that nblocks is valid */
707 assert(nblocks > 0);
709 /* get the log2 number of blocks to be allocated.
710 * if the number of blocks is not a log2 multiple,
711 * it will be rounded up to the next log2 multiple.
713 l2nb = BLKSTOL2(nblocks);
715 bmp = JFS_SBI(ip->i_sb)->bmap;
717 mapSize = bmp->db_mapsize;
719 /* the hint should be within the map */
720 if (hint >= mapSize) {
721 jfs_error(ip->i_sb, "dbAlloc: the hint is outside the map");
722 return -EIO;
725 /* if the number of blocks to be allocated is greater than the
726 * allocation group size, try to allocate anywhere.
728 if (l2nb > bmp->db_agl2size) {
729 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
731 rc = dbAllocAny(bmp, nblocks, l2nb, results);
733 goto write_unlock;
737 * If no hint, let dbNextAG recommend an allocation group
739 if (hint == 0)
740 goto pref_ag;
742 /* we would like to allocate close to the hint. adjust the
743 * hint to the block following the hint since the allocators
744 * will start looking for free space starting at this point.
746 blkno = hint + 1;
748 if (blkno >= bmp->db_mapsize)
749 goto pref_ag;
751 agno = blkno >> bmp->db_agl2size;
753 /* check if blkno crosses over into a new allocation group.
754 * if so, check if we should allow allocations within this
755 * allocation group.
757 if ((blkno & (bmp->db_agsize - 1)) == 0)
758 /* check if the AG is currenly being written to.
759 * if so, call dbNextAG() to find a non-busy
760 * AG with sufficient free space.
762 if (atomic_read(&bmp->db_active[agno]))
763 goto pref_ag;
765 /* check if the allocation request size can be satisfied from a
766 * single dmap. if so, try to allocate from the dmap containing
767 * the hint using a tiered strategy.
769 if (nblocks <= BPERDMAP) {
770 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
772 /* get the buffer for the dmap containing the hint.
774 rc = -EIO;
775 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
776 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
777 if (mp == NULL)
778 goto read_unlock;
780 dp = (struct dmap *) mp->data;
782 /* first, try to satisfy the allocation request with the
783 * blocks beginning at the hint.
785 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
786 != -ENOSPC) {
787 if (rc == 0) {
788 *results = blkno;
789 mark_metapage_dirty(mp);
792 release_metapage(mp);
793 goto read_unlock;
796 writers = atomic_read(&bmp->db_active[agno]);
797 if ((writers > 1) ||
798 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
800 * Someone else is writing in this allocation
801 * group. To avoid fragmenting, try another ag
803 release_metapage(mp);
804 IREAD_UNLOCK(ipbmap);
805 goto pref_ag;
808 /* next, try to satisfy the allocation request with blocks
809 * near the hint.
811 if ((rc =
812 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
813 != -ENOSPC) {
814 if (rc == 0)
815 mark_metapage_dirty(mp);
817 release_metapage(mp);
818 goto read_unlock;
821 /* try to satisfy the allocation request with blocks within
822 * the same dmap as the hint.
824 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
825 != -ENOSPC) {
826 if (rc == 0)
827 mark_metapage_dirty(mp);
829 release_metapage(mp);
830 goto read_unlock;
833 release_metapage(mp);
834 IREAD_UNLOCK(ipbmap);
837 /* try to satisfy the allocation request with blocks within
838 * the same allocation group as the hint.
840 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
841 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
842 goto write_unlock;
844 IWRITE_UNLOCK(ipbmap);
847 pref_ag:
849 * Let dbNextAG recommend a preferred allocation group
851 agno = dbNextAG(ipbmap);
852 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
854 /* Try to allocate within this allocation group. if that fails, try to
855 * allocate anywhere in the map.
857 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
858 rc = dbAllocAny(bmp, nblocks, l2nb, results);
860 write_unlock:
861 IWRITE_UNLOCK(ipbmap);
863 return (rc);
865 read_unlock:
866 IREAD_UNLOCK(ipbmap);
868 return (rc);
871 #ifdef _NOTYET
873 * NAME: dbAllocExact()
875 * FUNCTION: try to allocate the requested extent;
877 * PARAMETERS:
878 * ip - pointer to in-core inode;
879 * blkno - extent address;
880 * nblocks - extent length;
882 * RETURN VALUES:
883 * 0 - success
884 * -ENOSPC - insufficient disk resources
885 * -EIO - i/o error
887 int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
889 int rc;
890 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
891 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
892 struct dmap *dp;
893 s64 lblkno;
894 struct metapage *mp;
896 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
899 * validate extent request:
901 * note: defragfs policy:
902 * max 64 blocks will be moved.
903 * allocation request size must be satisfied from a single dmap.
905 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
906 IREAD_UNLOCK(ipbmap);
907 return -EINVAL;
910 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
911 /* the free space is no longer available */
912 IREAD_UNLOCK(ipbmap);
913 return -ENOSPC;
916 /* read in the dmap covering the extent */
917 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
918 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
919 if (mp == NULL) {
920 IREAD_UNLOCK(ipbmap);
921 return -EIO;
923 dp = (struct dmap *) mp->data;
925 /* try to allocate the requested extent */
926 rc = dbAllocNext(bmp, dp, blkno, nblocks);
928 IREAD_UNLOCK(ipbmap);
930 if (rc == 0)
931 mark_metapage_dirty(mp);
933 release_metapage(mp);
935 return (rc);
937 #endif /* _NOTYET */
940 * NAME: dbReAlloc()
942 * FUNCTION: attempt to extend a current allocation by a specified
943 * number of blocks.
945 * this routine attempts to satisfy the allocation request
946 * by first trying to extend the existing allocation in
947 * place by allocating the additional blocks as the blocks
948 * immediately following the current allocation. if these
949 * blocks are not available, this routine will attempt to
950 * allocate a new set of contiguous blocks large enough
951 * to cover the existing allocation plus the additional
952 * number of blocks required.
954 * PARAMETERS:
955 * ip - pointer to in-core inode requiring allocation.
956 * blkno - starting block of the current allocation.
957 * nblocks - number of contiguous blocks within the current
958 * allocation.
959 * addnblocks - number of blocks to add to the allocation.
960 * results - on successful return, set to the starting block number
961 * of the existing allocation if the existing allocation
962 * was extended in place or to a newly allocated contiguous
963 * range if the existing allocation could not be extended
964 * in place.
966 * RETURN VALUES:
967 * 0 - success
968 * -ENOSPC - insufficient disk resources
969 * -EIO - i/o error
972 dbReAlloc(struct inode *ip,
973 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
975 int rc;
977 /* try to extend the allocation in place.
979 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
980 *results = blkno;
981 return (0);
982 } else {
983 if (rc != -ENOSPC)
984 return (rc);
987 /* could not extend the allocation in place, so allocate a
988 * new set of blocks for the entire request (i.e. try to get
989 * a range of contiguous blocks large enough to cover the
990 * existing allocation plus the additional blocks.)
992 return (dbAlloc
993 (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
998 * NAME: dbExtend()
1000 * FUNCTION: attempt to extend a current allocation by a specified
1001 * number of blocks.
1003 * this routine attempts to satisfy the allocation request
1004 * by first trying to extend the existing allocation in
1005 * place by allocating the additional blocks as the blocks
1006 * immediately following the current allocation.
1008 * PARAMETERS:
1009 * ip - pointer to in-core inode requiring allocation.
1010 * blkno - starting block of the current allocation.
1011 * nblocks - number of contiguous blocks within the current
1012 * allocation.
1013 * addnblocks - number of blocks to add to the allocation.
1015 * RETURN VALUES:
1016 * 0 - success
1017 * -ENOSPC - insufficient disk resources
1018 * -EIO - i/o error
1020 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1022 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1023 s64 lblkno, lastblkno, extblkno;
1024 uint rel_block;
1025 struct metapage *mp;
1026 struct dmap *dp;
1027 int rc;
1028 struct inode *ipbmap = sbi->ipbmap;
1029 struct bmap *bmp;
1032 * We don't want a non-aligned extent to cross a page boundary
1034 if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1035 (rel_block + nblocks + addnblocks > sbi->nbperpage))
1036 return -ENOSPC;
1038 /* get the last block of the current allocation */
1039 lastblkno = blkno + nblocks - 1;
1041 /* determine the block number of the block following
1042 * the existing allocation.
1044 extblkno = lastblkno + 1;
1046 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
1048 /* better be within the file system */
1049 bmp = sbi->bmap;
1050 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1051 IREAD_UNLOCK(ipbmap);
1052 jfs_error(ip->i_sb,
1053 "dbExtend: the block is outside the filesystem");
1054 return -EIO;
1057 /* we'll attempt to extend the current allocation in place by
1058 * allocating the additional blocks as the blocks immediately
1059 * following the current allocation. we only try to extend the
1060 * current allocation in place if the number of additional blocks
1061 * can fit into a dmap, the last block of the current allocation
1062 * is not the last block of the file system, and the start of the
1063 * inplace extension is not on an allocation group boundary.
1065 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1066 (extblkno & (bmp->db_agsize - 1)) == 0) {
1067 IREAD_UNLOCK(ipbmap);
1068 return -ENOSPC;
1071 /* get the buffer for the dmap containing the first block
1072 * of the extension.
1074 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1075 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1076 if (mp == NULL) {
1077 IREAD_UNLOCK(ipbmap);
1078 return -EIO;
1081 dp = (struct dmap *) mp->data;
1083 /* try to allocate the blocks immediately following the
1084 * current allocation.
1086 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1088 IREAD_UNLOCK(ipbmap);
1090 /* were we successful ? */
1091 if (rc == 0)
1092 write_metapage(mp);
1093 else
1094 /* we were not successful */
1095 release_metapage(mp);
1098 return (rc);
1103 * NAME: dbAllocNext()
1105 * FUNCTION: attempt to allocate the blocks of the specified block
1106 * range within a dmap.
1108 * PARAMETERS:
1109 * bmp - pointer to bmap descriptor
1110 * dp - pointer to dmap.
1111 * blkno - starting block number of the range.
1112 * nblocks - number of contiguous free blocks of the range.
1114 * RETURN VALUES:
1115 * 0 - success
1116 * -ENOSPC - insufficient disk resources
1117 * -EIO - i/o error
1119 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1121 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1122 int nblocks)
1124 int dbitno, word, rembits, nb, nwords, wbitno, nw;
1125 int l2size;
1126 s8 *leaf;
1127 u32 mask;
1129 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1130 jfs_error(bmp->db_ipbmap->i_sb,
1131 "dbAllocNext: Corrupt dmap page");
1132 return -EIO;
1135 /* pick up a pointer to the leaves of the dmap tree.
1137 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1139 /* determine the bit number and word within the dmap of the
1140 * starting block.
1142 dbitno = blkno & (BPERDMAP - 1);
1143 word = dbitno >> L2DBWORD;
1145 /* check if the specified block range is contained within
1146 * this dmap.
1148 if (dbitno + nblocks > BPERDMAP)
1149 return -ENOSPC;
1151 /* check if the starting leaf indicates that anything
1152 * is free.
1154 if (leaf[word] == NOFREE)
1155 return -ENOSPC;
1157 /* check the dmaps words corresponding to block range to see
1158 * if the block range is free. not all bits of the first and
1159 * last words may be contained within the block range. if this
1160 * is the case, we'll work against those words (i.e. partial first
1161 * and/or last) on an individual basis (a single pass) and examine
1162 * the actual bits to determine if they are free. a single pass
1163 * will be used for all dmap words fully contained within the
1164 * specified range. within this pass, the leaves of the dmap
1165 * tree will be examined to determine if the blocks are free. a
1166 * single leaf may describe the free space of multiple dmap
1167 * words, so we may visit only a subset of the actual leaves
1168 * corresponding to the dmap words of the block range.
1170 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1171 /* determine the bit number within the word and
1172 * the number of bits within the word.
1174 wbitno = dbitno & (DBWORD - 1);
1175 nb = min(rembits, DBWORD - wbitno);
1177 /* check if only part of the word is to be examined.
1179 if (nb < DBWORD) {
1180 /* check if the bits are free.
1182 mask = (ONES << (DBWORD - nb) >> wbitno);
1183 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1184 return -ENOSPC;
1186 word += 1;
1187 } else {
1188 /* one or more dmap words are fully contained
1189 * within the block range. determine how many
1190 * words and how many bits.
1192 nwords = rembits >> L2DBWORD;
1193 nb = nwords << L2DBWORD;
1195 /* now examine the appropriate leaves to determine
1196 * if the blocks are free.
1198 while (nwords > 0) {
1199 /* does the leaf describe any free space ?
1201 if (leaf[word] < BUDMIN)
1202 return -ENOSPC;
1204 /* determine the l2 number of bits provided
1205 * by this leaf.
1207 l2size =
1208 min((int)leaf[word], NLSTOL2BSZ(nwords));
1210 /* determine how many words were handled.
1212 nw = BUDSIZE(l2size, BUDMIN);
1214 nwords -= nw;
1215 word += nw;
1220 /* allocate the blocks.
1222 return (dbAllocDmap(bmp, dp, blkno, nblocks));
1227 * NAME: dbAllocNear()
1229 * FUNCTION: attempt to allocate a number of contiguous free blocks near
1230 * a specified block (hint) within a dmap.
1232 * starting with the dmap leaf that covers the hint, we'll
1233 * check the next four contiguous leaves for sufficient free
1234 * space. if sufficient free space is found, we'll allocate
1235 * the desired free space.
1237 * PARAMETERS:
1238 * bmp - pointer to bmap descriptor
1239 * dp - pointer to dmap.
1240 * blkno - block number to allocate near.
1241 * nblocks - actual number of contiguous free blocks desired.
1242 * l2nb - log2 number of contiguous free blocks desired.
1243 * results - on successful return, set to the starting block number
1244 * of the newly allocated range.
1246 * RETURN VALUES:
1247 * 0 - success
1248 * -ENOSPC - insufficient disk resources
1249 * -EIO - i/o error
1251 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1253 static int
1254 dbAllocNear(struct bmap * bmp,
1255 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1257 int word, lword, rc;
1258 s8 *leaf;
1260 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1261 jfs_error(bmp->db_ipbmap->i_sb,
1262 "dbAllocNear: Corrupt dmap page");
1263 return -EIO;
1266 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1268 /* determine the word within the dmap that holds the hint
1269 * (i.e. blkno). also, determine the last word in the dmap
1270 * that we'll include in our examination.
1272 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1273 lword = min(word + 4, LPERDMAP);
1275 /* examine the leaves for sufficient free space.
1277 for (; word < lword; word++) {
1278 /* does the leaf describe sufficient free space ?
1280 if (leaf[word] < l2nb)
1281 continue;
1283 /* determine the block number within the file system
1284 * of the first block described by this dmap word.
1286 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1288 /* if not all bits of the dmap word are free, get the
1289 * starting bit number within the dmap word of the required
1290 * string of free bits and adjust the block number with the
1291 * value.
1293 if (leaf[word] < BUDMIN)
1294 blkno +=
1295 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1297 /* allocate the blocks.
1299 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1300 *results = blkno;
1302 return (rc);
1305 return -ENOSPC;
1310 * NAME: dbAllocAG()
1312 * FUNCTION: attempt to allocate the specified number of contiguous
1313 * free blocks within the specified allocation group.
1315 * unless the allocation group size is equal to the number
1316 * of blocks per dmap, the dmap control pages will be used to
1317 * find the required free space, if available. we start the
1318 * search at the highest dmap control page level which
1319 * distinctly describes the allocation group's free space
1320 * (i.e. the highest level at which the allocation group's
1321 * free space is not mixed in with that of any other group).
1322 * in addition, we start the search within this level at a
1323 * height of the dmapctl dmtree at which the nodes distinctly
1324 * describe the allocation group's free space. at this height,
1325 * the allocation group's free space may be represented by 1
1326 * or two sub-trees, depending on the allocation group size.
1327 * we search the top nodes of these subtrees left to right for
1328 * sufficient free space. if sufficient free space is found,
1329 * the subtree is searched to find the leftmost leaf that
1330 * has free space. once we have made it to the leaf, we
1331 * move the search to the next lower level dmap control page
1332 * corresponding to this leaf. we continue down the dmap control
1333 * pages until we find the dmap that contains or starts the
1334 * sufficient free space and we allocate at this dmap.
1336 * if the allocation group size is equal to the dmap size,
1337 * we'll start at the dmap corresponding to the allocation
1338 * group and attempt the allocation at this level.
1340 * the dmap control page search is also not performed if the
1341 * allocation group is completely free and we go to the first
1342 * dmap of the allocation group to do the allocation. this is
1343 * done because the allocation group may be part (not the first
1344 * part) of a larger binary buddy system, causing the dmap
1345 * control pages to indicate no free space (NOFREE) within
1346 * the allocation group.
1348 * PARAMETERS:
1349 * bmp - pointer to bmap descriptor
1350 * agno - allocation group number.
1351 * nblocks - actual number of contiguous free blocks desired.
1352 * l2nb - log2 number of contiguous free blocks desired.
1353 * results - on successful return, set to the starting block number
1354 * of the newly allocated range.
1356 * RETURN VALUES:
1357 * 0 - success
1358 * -ENOSPC - insufficient disk resources
1359 * -EIO - i/o error
1361 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1363 static int
1364 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1366 struct metapage *mp;
1367 struct dmapctl *dcp;
1368 int rc, ti, i, k, m, n, agperlev;
1369 s64 blkno, lblkno;
1370 int budmin;
1372 /* allocation request should not be for more than the
1373 * allocation group size.
1375 if (l2nb > bmp->db_agl2size) {
1376 jfs_error(bmp->db_ipbmap->i_sb,
1377 "dbAllocAG: allocation request is larger than the "
1378 "allocation group size");
1379 return -EIO;
1382 /* determine the starting block number of the allocation
1383 * group.
1385 blkno = (s64) agno << bmp->db_agl2size;
1387 /* check if the allocation group size is the minimum allocation
1388 * group size or if the allocation group is completely free. if
1389 * the allocation group size is the minimum size of BPERDMAP (i.e.
1390 * 1 dmap), there is no need to search the dmap control page (below)
1391 * that fully describes the allocation group since the allocation
1392 * group is already fully described by a dmap. in this case, we
1393 * just call dbAllocCtl() to search the dmap tree and allocate the
1394 * required space if available.
1396 * if the allocation group is completely free, dbAllocCtl() is
1397 * also called to allocate the required space. this is done for
1398 * two reasons. first, it makes no sense searching the dmap control
1399 * pages for free space when we know that free space exists. second,
1400 * the dmap control pages may indicate that the allocation group
1401 * has no free space if the allocation group is part (not the first
1402 * part) of a larger binary buddy system.
1404 if (bmp->db_agsize == BPERDMAP
1405 || bmp->db_agfree[agno] == bmp->db_agsize) {
1406 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1407 if ((rc == -ENOSPC) &&
1408 (bmp->db_agfree[agno] == bmp->db_agsize)) {
1409 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1410 (unsigned long long) blkno,
1411 (unsigned long long) nblocks);
1412 jfs_error(bmp->db_ipbmap->i_sb,
1413 "dbAllocAG: dbAllocCtl failed in free AG");
1415 return (rc);
1418 /* the buffer for the dmap control page that fully describes the
1419 * allocation group.
1421 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1422 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1423 if (mp == NULL)
1424 return -EIO;
1425 dcp = (struct dmapctl *) mp->data;
1426 budmin = dcp->budmin;
1428 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1429 jfs_error(bmp->db_ipbmap->i_sb,
1430 "dbAllocAG: Corrupt dmapctl page");
1431 release_metapage(mp);
1432 return -EIO;
1435 /* search the subtree(s) of the dmap control page that describes
1436 * the allocation group, looking for sufficient free space. to begin,
1437 * determine how many allocation groups are represented in a dmap
1438 * control page at the control page level (i.e. L0, L1, L2) that
1439 * fully describes an allocation group. next, determine the starting
1440 * tree index of this allocation group within the control page.
1442 agperlev =
1443 (1 << (L2LPERCTL - (bmp->db_agheigth << 1))) / bmp->db_agwidth;
1444 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1446 /* dmap control page trees fan-out by 4 and a single allocation
1447 * group may be described by 1 or 2 subtrees within the ag level
1448 * dmap control page, depending upon the ag size. examine the ag's
1449 * subtrees for sufficient free space, starting with the leftmost
1450 * subtree.
1452 for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1453 /* is there sufficient free space ?
1455 if (l2nb > dcp->stree[ti])
1456 continue;
1458 /* sufficient free space found in a subtree. now search down
1459 * the subtree to find the leftmost leaf that describes this
1460 * free space.
1462 for (k = bmp->db_agheigth; k > 0; k--) {
1463 for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1464 if (l2nb <= dcp->stree[m + n]) {
1465 ti = m + n;
1466 break;
1469 if (n == 4) {
1470 jfs_error(bmp->db_ipbmap->i_sb,
1471 "dbAllocAG: failed descending stree");
1472 release_metapage(mp);
1473 return -EIO;
1477 /* determine the block number within the file system
1478 * that corresponds to this leaf.
1480 if (bmp->db_aglevel == 2)
1481 blkno = 0;
1482 else if (bmp->db_aglevel == 1)
1483 blkno &= ~(MAXL1SIZE - 1);
1484 else /* bmp->db_aglevel == 0 */
1485 blkno &= ~(MAXL0SIZE - 1);
1487 blkno +=
1488 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1490 /* release the buffer in preparation for going down
1491 * the next level of dmap control pages.
1493 release_metapage(mp);
1495 /* check if we need to continue to search down the lower
1496 * level dmap control pages. we need to if the number of
1497 * blocks required is less than maximum number of blocks
1498 * described at the next lower level.
1500 if (l2nb < budmin) {
1502 /* search the lower level dmap control pages to get
1503 * the starting block number of the dmap that
1504 * contains or starts off the free space.
1506 if ((rc =
1507 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1508 &blkno))) {
1509 if (rc == -ENOSPC) {
1510 jfs_error(bmp->db_ipbmap->i_sb,
1511 "dbAllocAG: control page "
1512 "inconsistent");
1513 return -EIO;
1515 return (rc);
1519 /* allocate the blocks.
1521 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1522 if (rc == -ENOSPC) {
1523 jfs_error(bmp->db_ipbmap->i_sb,
1524 "dbAllocAG: unable to allocate blocks");
1525 rc = -EIO;
1527 return (rc);
1530 /* no space in the allocation group. release the buffer and
1531 * return -ENOSPC.
1533 release_metapage(mp);
1535 return -ENOSPC;
1540 * NAME: dbAllocAny()
1542 * FUNCTION: attempt to allocate the specified number of contiguous
1543 * free blocks anywhere in the file system.
1545 * dbAllocAny() attempts to find the sufficient free space by
1546 * searching down the dmap control pages, starting with the
1547 * highest level (i.e. L0, L1, L2) control page. if free space
1548 * large enough to satisfy the desired free space is found, the
1549 * desired free space is allocated.
1551 * PARAMETERS:
1552 * bmp - pointer to bmap descriptor
1553 * nblocks - actual number of contiguous free blocks desired.
1554 * l2nb - log2 number of contiguous free blocks desired.
1555 * results - on successful return, set to the starting block number
1556 * of the newly allocated range.
1558 * RETURN VALUES:
1559 * 0 - success
1560 * -ENOSPC - insufficient disk resources
1561 * -EIO - i/o error
1563 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1565 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1567 int rc;
1568 s64 blkno = 0;
1570 /* starting with the top level dmap control page, search
1571 * down the dmap control levels for sufficient free space.
1572 * if free space is found, dbFindCtl() returns the starting
1573 * block number of the dmap that contains or starts off the
1574 * range of free space.
1576 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1577 return (rc);
1579 /* allocate the blocks.
1581 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1582 if (rc == -ENOSPC) {
1583 jfs_error(bmp->db_ipbmap->i_sb,
1584 "dbAllocAny: unable to allocate blocks");
1585 return -EIO;
1587 return (rc);
1592 * NAME: dbFindCtl()
1594 * FUNCTION: starting at a specified dmap control page level and block
1595 * number, search down the dmap control levels for a range of
1596 * contiguous free blocks large enough to satisfy an allocation
1597 * request for the specified number of free blocks.
1599 * if sufficient contiguous free blocks are found, this routine
1600 * returns the starting block number within a dmap page that
1601 * contains or starts a range of contiqious free blocks that
1602 * is sufficient in size.
1604 * PARAMETERS:
1605 * bmp - pointer to bmap descriptor
1606 * level - starting dmap control page level.
1607 * l2nb - log2 number of contiguous free blocks desired.
1608 * *blkno - on entry, starting block number for conducting the search.
1609 * on successful return, the first block within a dmap page
1610 * that contains or starts a range of contiguous free blocks.
1612 * RETURN VALUES:
1613 * 0 - success
1614 * -ENOSPC - insufficient disk resources
1615 * -EIO - i/o error
1617 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1619 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1621 int rc, leafidx, lev;
1622 s64 b, lblkno;
1623 struct dmapctl *dcp;
1624 int budmin;
1625 struct metapage *mp;
1627 /* starting at the specified dmap control page level and block
1628 * number, search down the dmap control levels for the starting
1629 * block number of a dmap page that contains or starts off
1630 * sufficient free blocks.
1632 for (lev = level, b = *blkno; lev >= 0; lev--) {
1633 /* get the buffer of the dmap control page for the block
1634 * number and level (i.e. L0, L1, L2).
1636 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1637 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1638 if (mp == NULL)
1639 return -EIO;
1640 dcp = (struct dmapctl *) mp->data;
1641 budmin = dcp->budmin;
1643 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1644 jfs_error(bmp->db_ipbmap->i_sb,
1645 "dbFindCtl: Corrupt dmapctl page");
1646 release_metapage(mp);
1647 return -EIO;
1650 /* search the tree within the dmap control page for
1651 * sufficent free space. if sufficient free space is found,
1652 * dbFindLeaf() returns the index of the leaf at which
1653 * free space was found.
1655 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1657 /* release the buffer.
1659 release_metapage(mp);
1661 /* space found ?
1663 if (rc) {
1664 if (lev != level) {
1665 jfs_error(bmp->db_ipbmap->i_sb,
1666 "dbFindCtl: dmap inconsistent");
1667 return -EIO;
1669 return -ENOSPC;
1672 /* adjust the block number to reflect the location within
1673 * the dmap control page (i.e. the leaf) at which free
1674 * space was found.
1676 b += (((s64) leafidx) << budmin);
1678 /* we stop the search at this dmap control page level if
1679 * the number of blocks required is greater than or equal
1680 * to the maximum number of blocks described at the next
1681 * (lower) level.
1683 if (l2nb >= budmin)
1684 break;
1687 *blkno = b;
1688 return (0);
1693 * NAME: dbAllocCtl()
1695 * FUNCTION: attempt to allocate a specified number of contiguous
1696 * blocks starting within a specific dmap.
1698 * this routine is called by higher level routines that search
1699 * the dmap control pages above the actual dmaps for contiguous
1700 * free space. the result of successful searches by these
1701 * routines are the starting block numbers within dmaps, with
1702 * the dmaps themselves containing the desired contiguous free
1703 * space or starting a contiguous free space of desired size
1704 * that is made up of the blocks of one or more dmaps. these
1705 * calls should not fail due to insufficent resources.
1707 * this routine is called in some cases where it is not known
1708 * whether it will fail due to insufficient resources. more
1709 * specifically, this occurs when allocating from an allocation
1710 * group whose size is equal to the number of blocks per dmap.
1711 * in this case, the dmap control pages are not examined prior
1712 * to calling this routine (to save pathlength) and the call
1713 * might fail.
1715 * for a request size that fits within a dmap, this routine relies
1716 * upon the dmap's dmtree to find the requested contiguous free
1717 * space. for request sizes that are larger than a dmap, the
1718 * requested free space will start at the first block of the
1719 * first dmap (i.e. blkno).
1721 * PARAMETERS:
1722 * bmp - pointer to bmap descriptor
1723 * nblocks - actual number of contiguous free blocks to allocate.
1724 * l2nb - log2 number of contiguous free blocks to allocate.
1725 * blkno - starting block number of the dmap to start the allocation
1726 * from.
1727 * results - on successful return, set to the starting block number
1728 * of the newly allocated range.
1730 * RETURN VALUES:
1731 * 0 - success
1732 * -ENOSPC - insufficient disk resources
1733 * -EIO - i/o error
1735 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1737 static int
1738 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1740 int rc, nb;
1741 s64 b, lblkno, n;
1742 struct metapage *mp;
1743 struct dmap *dp;
1745 /* check if the allocation request is confined to a single dmap.
1747 if (l2nb <= L2BPERDMAP) {
1748 /* get the buffer for the dmap.
1750 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1751 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1752 if (mp == NULL)
1753 return -EIO;
1754 dp = (struct dmap *) mp->data;
1756 /* try to allocate the blocks.
1758 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1759 if (rc == 0)
1760 mark_metapage_dirty(mp);
1762 release_metapage(mp);
1764 return (rc);
1767 /* allocation request involving multiple dmaps. it must start on
1768 * a dmap boundary.
1770 assert((blkno & (BPERDMAP - 1)) == 0);
1772 /* allocate the blocks dmap by dmap.
1774 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1775 /* get the buffer for the dmap.
1777 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1778 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1779 if (mp == NULL) {
1780 rc = -EIO;
1781 goto backout;
1783 dp = (struct dmap *) mp->data;
1785 /* the dmap better be all free.
1787 if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1788 release_metapage(mp);
1789 jfs_error(bmp->db_ipbmap->i_sb,
1790 "dbAllocCtl: the dmap is not all free");
1791 rc = -EIO;
1792 goto backout;
1795 /* determine how many blocks to allocate from this dmap.
1797 nb = min(n, (s64)BPERDMAP);
1799 /* allocate the blocks from the dmap.
1801 if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1802 release_metapage(mp);
1803 goto backout;
1806 /* write the buffer.
1808 write_metapage(mp);
1811 /* set the results (starting block number) and return.
1813 *results = blkno;
1814 return (0);
1816 /* something failed in handling an allocation request involving
1817 * multiple dmaps. we'll try to clean up by backing out any
1818 * allocation that has already happened for this request. if
1819 * we fail in backing out the allocation, we'll mark the file
1820 * system to indicate that blocks have been leaked.
1822 backout:
1824 /* try to backout the allocations dmap by dmap.
1826 for (n = nblocks - n, b = blkno; n > 0;
1827 n -= BPERDMAP, b += BPERDMAP) {
1828 /* get the buffer for this dmap.
1830 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1831 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1832 if (mp == NULL) {
1833 /* could not back out. mark the file system
1834 * to indicate that we have leaked blocks.
1836 jfs_error(bmp->db_ipbmap->i_sb,
1837 "dbAllocCtl: I/O Error: Block Leakage.");
1838 continue;
1840 dp = (struct dmap *) mp->data;
1842 /* free the blocks is this dmap.
1844 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1845 /* could not back out. mark the file system
1846 * to indicate that we have leaked blocks.
1848 release_metapage(mp);
1849 jfs_error(bmp->db_ipbmap->i_sb,
1850 "dbAllocCtl: Block Leakage.");
1851 continue;
1854 /* write the buffer.
1856 write_metapage(mp);
1859 return (rc);
1864 * NAME: dbAllocDmapLev()
1866 * FUNCTION: attempt to allocate a specified number of contiguous blocks
1867 * from a specified dmap.
1869 * this routine checks if the contiguous blocks are available.
1870 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1871 * returned.
1873 * PARAMETERS:
1874 * mp - pointer to bmap descriptor
1875 * dp - pointer to dmap to attempt to allocate blocks from.
1876 * l2nb - log2 number of contiguous block desired.
1877 * nblocks - actual number of contiguous block desired.
1878 * results - on successful return, set to the starting block number
1879 * of the newly allocated range.
1881 * RETURN VALUES:
1882 * 0 - success
1883 * -ENOSPC - insufficient disk resources
1884 * -EIO - i/o error
1886 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1887 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1889 static int
1890 dbAllocDmapLev(struct bmap * bmp,
1891 struct dmap * dp, int nblocks, int l2nb, s64 * results)
1893 s64 blkno;
1894 int leafidx, rc;
1896 /* can't be more than a dmaps worth of blocks */
1897 assert(l2nb <= L2BPERDMAP);
1899 /* search the tree within the dmap page for sufficient
1900 * free space. if sufficient free space is found, dbFindLeaf()
1901 * returns the index of the leaf at which free space was found.
1903 if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1904 return -ENOSPC;
1906 /* determine the block number within the file system corresponding
1907 * to the leaf at which free space was found.
1909 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1911 /* if not all bits of the dmap word are free, get the starting
1912 * bit number within the dmap word of the required string of free
1913 * bits and adjust the block number with this value.
1915 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1916 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1918 /* allocate the blocks */
1919 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1920 *results = blkno;
1922 return (rc);
1927 * NAME: dbAllocDmap()
1929 * FUNCTION: adjust the disk allocation map to reflect the allocation
1930 * of a specified block range within a dmap.
1932 * this routine allocates the specified blocks from the dmap
1933 * through a call to dbAllocBits(). if the allocation of the
1934 * block range causes the maximum string of free blocks within
1935 * the dmap to change (i.e. the value of the root of the dmap's
1936 * dmtree), this routine will cause this change to be reflected
1937 * up through the appropriate levels of the dmap control pages
1938 * by a call to dbAdjCtl() for the L0 dmap control page that
1939 * covers this dmap.
1941 * PARAMETERS:
1942 * bmp - pointer to bmap descriptor
1943 * dp - pointer to dmap to allocate the block range from.
1944 * blkno - starting block number of the block to be allocated.
1945 * nblocks - number of blocks to be allocated.
1947 * RETURN VALUES:
1948 * 0 - success
1949 * -EIO - i/o error
1951 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
1953 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
1954 int nblocks)
1956 s8 oldroot;
1957 int rc;
1959 /* save the current value of the root (i.e. maximum free string)
1960 * of the dmap tree.
1962 oldroot = dp->tree.stree[ROOT];
1964 /* allocate the specified (blocks) bits */
1965 dbAllocBits(bmp, dp, blkno, nblocks);
1967 /* if the root has not changed, done. */
1968 if (dp->tree.stree[ROOT] == oldroot)
1969 return (0);
1971 /* root changed. bubble the change up to the dmap control pages.
1972 * if the adjustment of the upper level control pages fails,
1973 * backout the bit allocation (thus making everything consistent).
1975 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
1976 dbFreeBits(bmp, dp, blkno, nblocks);
1978 return (rc);
1983 * NAME: dbFreeDmap()
1985 * FUNCTION: adjust the disk allocation map to reflect the allocation
1986 * of a specified block range within a dmap.
1988 * this routine frees the specified blocks from the dmap through
1989 * a call to dbFreeBits(). if the deallocation of the block range
1990 * causes the maximum string of free blocks within the dmap to
1991 * change (i.e. the value of the root of the dmap's dmtree), this
1992 * routine will cause this change to be reflected up through the
1993 * appropriate levels of the dmap control pages by a call to
1994 * dbAdjCtl() for the L0 dmap control page that covers this dmap.
1996 * PARAMETERS:
1997 * bmp - pointer to bmap descriptor
1998 * dp - pointer to dmap to free the block range from.
1999 * blkno - starting block number of the block to be freed.
2000 * nblocks - number of blocks to be freed.
2002 * RETURN VALUES:
2003 * 0 - success
2004 * -EIO - i/o error
2006 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2008 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2009 int nblocks)
2011 s8 oldroot;
2012 int rc = 0, word;
2014 /* save the current value of the root (i.e. maximum free string)
2015 * of the dmap tree.
2017 oldroot = dp->tree.stree[ROOT];
2019 /* free the specified (blocks) bits */
2020 rc = dbFreeBits(bmp, dp, blkno, nblocks);
2022 /* if error or the root has not changed, done. */
2023 if (rc || (dp->tree.stree[ROOT] == oldroot))
2024 return (rc);
2026 /* root changed. bubble the change up to the dmap control pages.
2027 * if the adjustment of the upper level control pages fails,
2028 * backout the deallocation.
2030 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2031 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2033 /* as part of backing out the deallocation, we will have
2034 * to back split the dmap tree if the deallocation caused
2035 * the freed blocks to become part of a larger binary buddy
2036 * system.
2038 if (dp->tree.stree[word] == NOFREE)
2039 dbBackSplit((dmtree_t *) & dp->tree, word);
2041 dbAllocBits(bmp, dp, blkno, nblocks);
2044 return (rc);
2049 * NAME: dbAllocBits()
2051 * FUNCTION: allocate a specified block range from a dmap.
2053 * this routine updates the dmap to reflect the working
2054 * state allocation of the specified block range. it directly
2055 * updates the bits of the working map and causes the adjustment
2056 * of the binary buddy system described by the dmap's dmtree
2057 * leaves to reflect the bits allocated. it also causes the
2058 * dmap's dmtree, as a whole, to reflect the allocated range.
2060 * PARAMETERS:
2061 * bmp - pointer to bmap descriptor
2062 * dp - pointer to dmap to allocate bits from.
2063 * blkno - starting block number of the bits to be allocated.
2064 * nblocks - number of bits to be allocated.
2066 * RETURN VALUES: none
2068 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2070 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2071 int nblocks)
2073 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2074 dmtree_t *tp = (dmtree_t *) & dp->tree;
2075 int size;
2076 s8 *leaf;
2078 /* pick up a pointer to the leaves of the dmap tree */
2079 leaf = dp->tree.stree + LEAFIND;
2081 /* determine the bit number and word within the dmap of the
2082 * starting block.
2084 dbitno = blkno & (BPERDMAP - 1);
2085 word = dbitno >> L2DBWORD;
2087 /* block range better be within the dmap */
2088 assert(dbitno + nblocks <= BPERDMAP);
2090 /* allocate the bits of the dmap's words corresponding to the block
2091 * range. not all bits of the first and last words may be contained
2092 * within the block range. if this is the case, we'll work against
2093 * those words (i.e. partial first and/or last) on an individual basis
2094 * (a single pass), allocating the bits of interest by hand and
2095 * updating the leaf corresponding to the dmap word. a single pass
2096 * will be used for all dmap words fully contained within the
2097 * specified range. within this pass, the bits of all fully contained
2098 * dmap words will be marked as free in a single shot and the leaves
2099 * will be updated. a single leaf may describe the free space of
2100 * multiple dmap words, so we may update only a subset of the actual
2101 * leaves corresponding to the dmap words of the block range.
2103 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2104 /* determine the bit number within the word and
2105 * the number of bits within the word.
2107 wbitno = dbitno & (DBWORD - 1);
2108 nb = min(rembits, DBWORD - wbitno);
2110 /* check if only part of a word is to be allocated.
2112 if (nb < DBWORD) {
2113 /* allocate (set to 1) the appropriate bits within
2114 * this dmap word.
2116 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2117 >> wbitno);
2119 /* update the leaf for this dmap word. in addition
2120 * to setting the leaf value to the binary buddy max
2121 * of the updated dmap word, dbSplit() will split
2122 * the binary system of the leaves if need be.
2124 dbSplit(tp, word, BUDMIN,
2125 dbMaxBud((u8 *) & dp->wmap[word]));
2127 word += 1;
2128 } else {
2129 /* one or more dmap words are fully contained
2130 * within the block range. determine how many
2131 * words and allocate (set to 1) the bits of these
2132 * words.
2134 nwords = rembits >> L2DBWORD;
2135 memset(&dp->wmap[word], (int) ONES, nwords * 4);
2137 /* determine how many bits.
2139 nb = nwords << L2DBWORD;
2141 /* now update the appropriate leaves to reflect
2142 * the allocated words.
2144 for (; nwords > 0; nwords -= nw) {
2145 if (leaf[word] < BUDMIN) {
2146 jfs_error(bmp->db_ipbmap->i_sb,
2147 "dbAllocBits: leaf page "
2148 "corrupt");
2149 break;
2152 /* determine what the leaf value should be
2153 * updated to as the minimum of the l2 number
2154 * of bits being allocated and the l2 number
2155 * of bits currently described by this leaf.
2157 size = min((int)leaf[word], NLSTOL2BSZ(nwords));
2159 /* update the leaf to reflect the allocation.
2160 * in addition to setting the leaf value to
2161 * NOFREE, dbSplit() will split the binary
2162 * system of the leaves to reflect the current
2163 * allocation (size).
2165 dbSplit(tp, word, size, NOFREE);
2167 /* get the number of dmap words handled */
2168 nw = BUDSIZE(size, BUDMIN);
2169 word += nw;
2174 /* update the free count for this dmap */
2175 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
2177 BMAP_LOCK(bmp);
2179 /* if this allocation group is completely free,
2180 * update the maximum allocation group number if this allocation
2181 * group is the new max.
2183 agno = blkno >> bmp->db_agl2size;
2184 if (agno > bmp->db_maxag)
2185 bmp->db_maxag = agno;
2187 /* update the free count for the allocation group and map */
2188 bmp->db_agfree[agno] -= nblocks;
2189 bmp->db_nfree -= nblocks;
2191 BMAP_UNLOCK(bmp);
2196 * NAME: dbFreeBits()
2198 * FUNCTION: free a specified block range from a dmap.
2200 * this routine updates the dmap to reflect the working
2201 * state allocation of the specified block range. it directly
2202 * updates the bits of the working map and causes the adjustment
2203 * of the binary buddy system described by the dmap's dmtree
2204 * leaves to reflect the bits freed. it also causes the dmap's
2205 * dmtree, as a whole, to reflect the deallocated range.
2207 * PARAMETERS:
2208 * bmp - pointer to bmap descriptor
2209 * dp - pointer to dmap to free bits from.
2210 * blkno - starting block number of the bits to be freed.
2211 * nblocks - number of bits to be freed.
2213 * RETURN VALUES: 0 for success
2215 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2217 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2218 int nblocks)
2220 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2221 dmtree_t *tp = (dmtree_t *) & dp->tree;
2222 int rc = 0;
2223 int size;
2225 /* determine the bit number and word within the dmap of the
2226 * starting block.
2228 dbitno = blkno & (BPERDMAP - 1);
2229 word = dbitno >> L2DBWORD;
2231 /* block range better be within the dmap.
2233 assert(dbitno + nblocks <= BPERDMAP);
2235 /* free the bits of the dmaps words corresponding to the block range.
2236 * not all bits of the first and last words may be contained within
2237 * the block range. if this is the case, we'll work against those
2238 * words (i.e. partial first and/or last) on an individual basis
2239 * (a single pass), freeing the bits of interest by hand and updating
2240 * the leaf corresponding to the dmap word. a single pass will be used
2241 * for all dmap words fully contained within the specified range.
2242 * within this pass, the bits of all fully contained dmap words will
2243 * be marked as free in a single shot and the leaves will be updated. a
2244 * single leaf may describe the free space of multiple dmap words,
2245 * so we may update only a subset of the actual leaves corresponding
2246 * to the dmap words of the block range.
2248 * dbJoin() is used to update leaf values and will join the binary
2249 * buddy system of the leaves if the new leaf values indicate this
2250 * should be done.
2252 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2253 /* determine the bit number within the word and
2254 * the number of bits within the word.
2256 wbitno = dbitno & (DBWORD - 1);
2257 nb = min(rembits, DBWORD - wbitno);
2259 /* check if only part of a word is to be freed.
2261 if (nb < DBWORD) {
2262 /* free (zero) the appropriate bits within this
2263 * dmap word.
2265 dp->wmap[word] &=
2266 cpu_to_le32(~(ONES << (DBWORD - nb)
2267 >> wbitno));
2269 /* update the leaf for this dmap word.
2271 rc = dbJoin(tp, word,
2272 dbMaxBud((u8 *) & dp->wmap[word]));
2273 if (rc)
2274 return rc;
2276 word += 1;
2277 } else {
2278 /* one or more dmap words are fully contained
2279 * within the block range. determine how many
2280 * words and free (zero) the bits of these words.
2282 nwords = rembits >> L2DBWORD;
2283 memset(&dp->wmap[word], 0, nwords * 4);
2285 /* determine how many bits.
2287 nb = nwords << L2DBWORD;
2289 /* now update the appropriate leaves to reflect
2290 * the freed words.
2292 for (; nwords > 0; nwords -= nw) {
2293 /* determine what the leaf value should be
2294 * updated to as the minimum of the l2 number
2295 * of bits being freed and the l2 (max) number
2296 * of bits that can be described by this leaf.
2298 size =
2299 min(LITOL2BSZ
2300 (word, L2LPERDMAP, BUDMIN),
2301 NLSTOL2BSZ(nwords));
2303 /* update the leaf.
2305 rc = dbJoin(tp, word, size);
2306 if (rc)
2307 return rc;
2309 /* get the number of dmap words handled.
2311 nw = BUDSIZE(size, BUDMIN);
2312 word += nw;
2317 /* update the free count for this dmap.
2319 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
2321 BMAP_LOCK(bmp);
2323 /* update the free count for the allocation group and
2324 * map.
2326 agno = blkno >> bmp->db_agl2size;
2327 bmp->db_nfree += nblocks;
2328 bmp->db_agfree[agno] += nblocks;
2330 /* check if this allocation group is not completely free and
2331 * if it is currently the maximum (rightmost) allocation group.
2332 * if so, establish the new maximum allocation group number by
2333 * searching left for the first allocation group with allocation.
2335 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2336 (agno == bmp->db_numag - 1 &&
2337 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2338 while (bmp->db_maxag > 0) {
2339 bmp->db_maxag -= 1;
2340 if (bmp->db_agfree[bmp->db_maxag] !=
2341 bmp->db_agsize)
2342 break;
2345 /* re-establish the allocation group preference if the
2346 * current preference is right of the maximum allocation
2347 * group.
2349 if (bmp->db_agpref > bmp->db_maxag)
2350 bmp->db_agpref = bmp->db_maxag;
2353 BMAP_UNLOCK(bmp);
2355 return 0;
2360 * NAME: dbAdjCtl()
2362 * FUNCTION: adjust a dmap control page at a specified level to reflect
2363 * the change in a lower level dmap or dmap control page's
2364 * maximum string of free blocks (i.e. a change in the root
2365 * of the lower level object's dmtree) due to the allocation
2366 * or deallocation of a range of blocks with a single dmap.
2368 * on entry, this routine is provided with the new value of
2369 * the lower level dmap or dmap control page root and the
2370 * starting block number of the block range whose allocation
2371 * or deallocation resulted in the root change. this range
2372 * is respresented by a single leaf of the current dmapctl
2373 * and the leaf will be updated with this value, possibly
2374 * causing a binary buddy system within the leaves to be
2375 * split or joined. the update may also cause the dmapctl's
2376 * dmtree to be updated.
2378 * if the adjustment of the dmap control page, itself, causes its
2379 * root to change, this change will be bubbled up to the next dmap
2380 * control level by a recursive call to this routine, specifying
2381 * the new root value and the next dmap control page level to
2382 * be adjusted.
2383 * PARAMETERS:
2384 * bmp - pointer to bmap descriptor
2385 * blkno - the first block of a block range within a dmap. it is
2386 * the allocation or deallocation of this block range that
2387 * requires the dmap control page to be adjusted.
2388 * newval - the new value of the lower level dmap or dmap control
2389 * page root.
2390 * alloc - 'true' if adjustment is due to an allocation.
2391 * level - current level of dmap control page (i.e. L0, L1, L2) to
2392 * be adjusted.
2394 * RETURN VALUES:
2395 * 0 - success
2396 * -EIO - i/o error
2398 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2400 static int
2401 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2403 struct metapage *mp;
2404 s8 oldroot;
2405 int oldval;
2406 s64 lblkno;
2407 struct dmapctl *dcp;
2408 int rc, leafno, ti;
2410 /* get the buffer for the dmap control page for the specified
2411 * block number and control page level.
2413 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2414 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2415 if (mp == NULL)
2416 return -EIO;
2417 dcp = (struct dmapctl *) mp->data;
2419 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2420 jfs_error(bmp->db_ipbmap->i_sb,
2421 "dbAdjCtl: Corrupt dmapctl page");
2422 release_metapage(mp);
2423 return -EIO;
2426 /* determine the leaf number corresponding to the block and
2427 * the index within the dmap control tree.
2429 leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2430 ti = leafno + le32_to_cpu(dcp->leafidx);
2432 /* save the current leaf value and the current root level (i.e.
2433 * maximum l2 free string described by this dmapctl).
2435 oldval = dcp->stree[ti];
2436 oldroot = dcp->stree[ROOT];
2438 /* check if this is a control page update for an allocation.
2439 * if so, update the leaf to reflect the new leaf value using
2440 * dbSplit(); otherwise (deallocation), use dbJoin() to udpate
2441 * the leaf with the new value. in addition to updating the
2442 * leaf, dbSplit() will also split the binary buddy system of
2443 * the leaves, if required, and bubble new values within the
2444 * dmapctl tree, if required. similarly, dbJoin() will join
2445 * the binary buddy system of leaves and bubble new values up
2446 * the dmapctl tree as required by the new leaf value.
2448 if (alloc) {
2449 /* check if we are in the middle of a binary buddy
2450 * system. this happens when we are performing the
2451 * first allocation out of an allocation group that
2452 * is part (not the first part) of a larger binary
2453 * buddy system. if we are in the middle, back split
2454 * the system prior to calling dbSplit() which assumes
2455 * that it is at the front of a binary buddy system.
2457 if (oldval == NOFREE) {
2458 rc = dbBackSplit((dmtree_t *) dcp, leafno);
2459 if (rc)
2460 return rc;
2461 oldval = dcp->stree[ti];
2463 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2464 } else {
2465 rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2466 if (rc)
2467 return rc;
2470 /* check if the root of the current dmap control page changed due
2471 * to the update and if the current dmap control page is not at
2472 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
2473 * root changed and this is not the top level), call this routine
2474 * again (recursion) for the next higher level of the mapping to
2475 * reflect the change in root for the current dmap control page.
2477 if (dcp->stree[ROOT] != oldroot) {
2478 /* are we below the top level of the map. if so,
2479 * bubble the root up to the next higher level.
2481 if (level < bmp->db_maxlevel) {
2482 /* bubble up the new root of this dmap control page to
2483 * the next level.
2485 if ((rc =
2486 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2487 level + 1))) {
2488 /* something went wrong in bubbling up the new
2489 * root value, so backout the changes to the
2490 * current dmap control page.
2492 if (alloc) {
2493 dbJoin((dmtree_t *) dcp, leafno,
2494 oldval);
2495 } else {
2496 /* the dbJoin() above might have
2497 * caused a larger binary buddy system
2498 * to form and we may now be in the
2499 * middle of it. if this is the case,
2500 * back split the buddies.
2502 if (dcp->stree[ti] == NOFREE)
2503 dbBackSplit((dmtree_t *)
2504 dcp, leafno);
2505 dbSplit((dmtree_t *) dcp, leafno,
2506 dcp->budmin, oldval);
2509 /* release the buffer and return the error.
2511 release_metapage(mp);
2512 return (rc);
2514 } else {
2515 /* we're at the top level of the map. update
2516 * the bmap control page to reflect the size
2517 * of the maximum free buddy system.
2519 assert(level == bmp->db_maxlevel);
2520 if (bmp->db_maxfreebud != oldroot) {
2521 jfs_error(bmp->db_ipbmap->i_sb,
2522 "dbAdjCtl: the maximum free buddy is "
2523 "not the old root");
2525 bmp->db_maxfreebud = dcp->stree[ROOT];
2529 /* write the buffer.
2531 write_metapage(mp);
2533 return (0);
2538 * NAME: dbSplit()
2540 * FUNCTION: update the leaf of a dmtree with a new value, splitting
2541 * the leaf from the binary buddy system of the dmtree's
2542 * leaves, as required.
2544 * PARAMETERS:
2545 * tp - pointer to the tree containing the leaf.
2546 * leafno - the number of the leaf to be updated.
2547 * splitsz - the size the binary buddy system starting at the leaf
2548 * must be split to, specified as the log2 number of blocks.
2549 * newval - the new value for the leaf.
2551 * RETURN VALUES: none
2553 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2555 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2557 int budsz;
2558 int cursz;
2559 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2561 /* check if the leaf needs to be split.
2563 if (leaf[leafno] > tp->dmt_budmin) {
2564 /* the split occurs by cutting the buddy system in half
2565 * at the specified leaf until we reach the specified
2566 * size. pick up the starting split size (current size
2567 * - 1 in l2) and the corresponding buddy size.
2569 cursz = leaf[leafno] - 1;
2570 budsz = BUDSIZE(cursz, tp->dmt_budmin);
2572 /* split until we reach the specified size.
2574 while (cursz >= splitsz) {
2575 /* update the buddy's leaf with its new value.
2577 dbAdjTree(tp, leafno ^ budsz, cursz);
2579 /* on to the next size and buddy.
2581 cursz -= 1;
2582 budsz >>= 1;
2586 /* adjust the dmap tree to reflect the specified leaf's new
2587 * value.
2589 dbAdjTree(tp, leafno, newval);
2594 * NAME: dbBackSplit()
2596 * FUNCTION: back split the binary buddy system of dmtree leaves
2597 * that hold a specified leaf until the specified leaf
2598 * starts its own binary buddy system.
2600 * the allocators typically perform allocations at the start
2601 * of binary buddy systems and dbSplit() is used to accomplish
2602 * any required splits. in some cases, however, allocation
2603 * may occur in the middle of a binary system and requires a
2604 * back split, with the split proceeding out from the middle of
2605 * the system (less efficient) rather than the start of the
2606 * system (more efficient). the cases in which a back split
2607 * is required are rare and are limited to the first allocation
2608 * within an allocation group which is a part (not first part)
2609 * of a larger binary buddy system and a few exception cases
2610 * in which a previous join operation must be backed out.
2612 * PARAMETERS:
2613 * tp - pointer to the tree containing the leaf.
2614 * leafno - the number of the leaf to be updated.
2616 * RETURN VALUES: none
2618 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2620 static int dbBackSplit(dmtree_t * tp, int leafno)
2622 int budsz, bud, w, bsz, size;
2623 int cursz;
2624 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2626 /* leaf should be part (not first part) of a binary
2627 * buddy system.
2629 assert(leaf[leafno] == NOFREE);
2631 /* the back split is accomplished by iteratively finding the leaf
2632 * that starts the buddy system that contains the specified leaf and
2633 * splitting that system in two. this iteration continues until
2634 * the specified leaf becomes the start of a buddy system.
2636 * determine maximum possible l2 size for the specified leaf.
2638 size =
2639 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2640 tp->dmt_budmin);
2642 /* determine the number of leaves covered by this size. this
2643 * is the buddy size that we will start with as we search for
2644 * the buddy system that contains the specified leaf.
2646 budsz = BUDSIZE(size, tp->dmt_budmin);
2648 /* back split.
2650 while (leaf[leafno] == NOFREE) {
2651 /* find the leftmost buddy leaf.
2653 for (w = leafno, bsz = budsz;; bsz <<= 1,
2654 w = (w < bud) ? w : bud) {
2655 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2656 jfs_err("JFS: block map error in dbBackSplit");
2657 return -EIO;
2660 /* determine the buddy.
2662 bud = w ^ bsz;
2664 /* check if this buddy is the start of the system.
2666 if (leaf[bud] != NOFREE) {
2667 /* split the leaf at the start of the
2668 * system in two.
2670 cursz = leaf[bud] - 1;
2671 dbSplit(tp, bud, cursz, cursz);
2672 break;
2677 if (leaf[leafno] != size) {
2678 jfs_err("JFS: wrong leaf value in dbBackSplit");
2679 return -EIO;
2681 return 0;
2686 * NAME: dbJoin()
2688 * FUNCTION: update the leaf of a dmtree with a new value, joining
2689 * the leaf with other leaves of the dmtree into a multi-leaf
2690 * binary buddy system, as required.
2692 * PARAMETERS:
2693 * tp - pointer to the tree containing the leaf.
2694 * leafno - the number of the leaf to be updated.
2695 * newval - the new value for the leaf.
2697 * RETURN VALUES: none
2699 static int dbJoin(dmtree_t * tp, int leafno, int newval)
2701 int budsz, buddy;
2702 s8 *leaf;
2704 /* can the new leaf value require a join with other leaves ?
2706 if (newval >= tp->dmt_budmin) {
2707 /* pickup a pointer to the leaves of the tree.
2709 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2711 /* try to join the specified leaf into a large binary
2712 * buddy system. the join proceeds by attempting to join
2713 * the specified leafno with its buddy (leaf) at new value.
2714 * if the join occurs, we attempt to join the left leaf
2715 * of the joined buddies with its buddy at new value + 1.
2716 * we continue to join until we find a buddy that cannot be
2717 * joined (does not have a value equal to the size of the
2718 * last join) or until all leaves have been joined into a
2719 * single system.
2721 * get the buddy size (number of words covered) of
2722 * the new value.
2724 budsz = BUDSIZE(newval, tp->dmt_budmin);
2726 /* try to join.
2728 while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2729 /* get the buddy leaf.
2731 buddy = leafno ^ budsz;
2733 /* if the leaf's new value is greater than its
2734 * buddy's value, we join no more.
2736 if (newval > leaf[buddy])
2737 break;
2739 /* It shouldn't be less */
2740 if (newval < leaf[buddy])
2741 return -EIO;
2743 /* check which (leafno or buddy) is the left buddy.
2744 * the left buddy gets to claim the blocks resulting
2745 * from the join while the right gets to claim none.
2746 * the left buddy is also eligable to participate in
2747 * a join at the next higher level while the right
2748 * is not.
2751 if (leafno < buddy) {
2752 /* leafno is the left buddy.
2754 dbAdjTree(tp, buddy, NOFREE);
2755 } else {
2756 /* buddy is the left buddy and becomes
2757 * leafno.
2759 dbAdjTree(tp, leafno, NOFREE);
2760 leafno = buddy;
2763 /* on to try the next join.
2765 newval += 1;
2766 budsz <<= 1;
2770 /* update the leaf value.
2772 dbAdjTree(tp, leafno, newval);
2774 return 0;
2779 * NAME: dbAdjTree()
2781 * FUNCTION: update a leaf of a dmtree with a new value, adjusting
2782 * the dmtree, as required, to reflect the new leaf value.
2783 * the combination of any buddies must already be done before
2784 * this is called.
2786 * PARAMETERS:
2787 * tp - pointer to the tree to be adjusted.
2788 * leafno - the number of the leaf to be updated.
2789 * newval - the new value for the leaf.
2791 * RETURN VALUES: none
2793 static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2795 int lp, pp, k;
2796 int max;
2798 /* pick up the index of the leaf for this leafno.
2800 lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2802 /* is the current value the same as the old value ? if so,
2803 * there is nothing to do.
2805 if (tp->dmt_stree[lp] == newval)
2806 return;
2808 /* set the new value.
2810 tp->dmt_stree[lp] = newval;
2812 /* bubble the new value up the tree as required.
2814 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2815 /* get the index of the first leaf of the 4 leaf
2816 * group containing the specified leaf (leafno).
2818 lp = ((lp - 1) & ~0x03) + 1;
2820 /* get the index of the parent of this 4 leaf group.
2822 pp = (lp - 1) >> 2;
2824 /* determine the maximum of the 4 leaves.
2826 max = TREEMAX(&tp->dmt_stree[lp]);
2828 /* if the maximum of the 4 is the same as the
2829 * parent's value, we're done.
2831 if (tp->dmt_stree[pp] == max)
2832 break;
2834 /* parent gets new value.
2836 tp->dmt_stree[pp] = max;
2838 /* parent becomes leaf for next go-round.
2840 lp = pp;
2846 * NAME: dbFindLeaf()
2848 * FUNCTION: search a dmtree_t for sufficient free blocks, returning
2849 * the index of a leaf describing the free blocks if
2850 * sufficient free blocks are found.
2852 * the search starts at the top of the dmtree_t tree and
2853 * proceeds down the tree to the leftmost leaf with sufficient
2854 * free space.
2856 * PARAMETERS:
2857 * tp - pointer to the tree to be searched.
2858 * l2nb - log2 number of free blocks to search for.
2859 * leafidx - return pointer to be set to the index of the leaf
2860 * describing at least l2nb free blocks if sufficient
2861 * free blocks are found.
2863 * RETURN VALUES:
2864 * 0 - success
2865 * -ENOSPC - insufficient free blocks.
2867 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2869 int ti, n = 0, k, x = 0;
2871 /* first check the root of the tree to see if there is
2872 * sufficient free space.
2874 if (l2nb > tp->dmt_stree[ROOT])
2875 return -ENOSPC;
2877 /* sufficient free space available. now search down the tree
2878 * starting at the next level for the leftmost leaf that
2879 * describes sufficient free space.
2881 for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2882 k > 0; k--, ti = ((ti + n) << 2) + 1) {
2883 /* search the four nodes at this level, starting from
2884 * the left.
2886 for (x = ti, n = 0; n < 4; n++) {
2887 /* sufficient free space found. move to the next
2888 * level (or quit if this is the last level).
2890 if (l2nb <= tp->dmt_stree[x + n])
2891 break;
2894 /* better have found something since the higher
2895 * levels of the tree said it was here.
2897 assert(n < 4);
2900 /* set the return to the leftmost leaf describing sufficient
2901 * free space.
2903 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2905 return (0);
2910 * NAME: dbFindBits()
2912 * FUNCTION: find a specified number of binary buddy free bits within a
2913 * dmap bitmap word value.
2915 * this routine searches the bitmap value for (1 << l2nb) free
2916 * bits at (1 << l2nb) alignments within the value.
2918 * PARAMETERS:
2919 * word - dmap bitmap word value.
2920 * l2nb - number of free bits specified as a log2 number.
2922 * RETURN VALUES:
2923 * starting bit number of free bits.
2925 static int dbFindBits(u32 word, int l2nb)
2927 int bitno, nb;
2928 u32 mask;
2930 /* get the number of bits.
2932 nb = 1 << l2nb;
2933 assert(nb <= DBWORD);
2935 /* complement the word so we can use a mask (i.e. 0s represent
2936 * free bits) and compute the mask.
2938 word = ~word;
2939 mask = ONES << (DBWORD - nb);
2941 /* scan the word for nb free bits at nb alignments.
2943 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2944 if ((mask & word) == mask)
2945 break;
2948 ASSERT(bitno < 32);
2950 /* return the bit number.
2952 return (bitno);
2957 * NAME: dbMaxBud(u8 *cp)
2959 * FUNCTION: determine the largest binary buddy string of free
2960 * bits within 32-bits of the map.
2962 * PARAMETERS:
2963 * cp - pointer to the 32-bit value.
2965 * RETURN VALUES:
2966 * largest binary buddy of free bits within a dmap word.
2968 static int dbMaxBud(u8 * cp)
2970 signed char tmp1, tmp2;
2972 /* check if the wmap word is all free. if so, the
2973 * free buddy size is BUDMIN.
2975 if (*((uint *) cp) == 0)
2976 return (BUDMIN);
2978 /* check if the wmap word is half free. if so, the
2979 * free buddy size is BUDMIN-1.
2981 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
2982 return (BUDMIN - 1);
2984 /* not all free or half free. determine the free buddy
2985 * size thru table lookup using quarters of the wmap word.
2987 tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
2988 tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
2989 return (max(tmp1, tmp2));
2994 * NAME: cnttz(uint word)
2996 * FUNCTION: determine the number of trailing zeros within a 32-bit
2997 * value.
2999 * PARAMETERS:
3000 * value - 32-bit value to be examined.
3002 * RETURN VALUES:
3003 * count of trailing zeros
3005 static int cnttz(u32 word)
3007 int n;
3009 for (n = 0; n < 32; n++, word >>= 1) {
3010 if (word & 0x01)
3011 break;
3014 return (n);
3019 * NAME: cntlz(u32 value)
3021 * FUNCTION: determine the number of leading zeros within a 32-bit
3022 * value.
3024 * PARAMETERS:
3025 * value - 32-bit value to be examined.
3027 * RETURN VALUES:
3028 * count of leading zeros
3030 static int cntlz(u32 value)
3032 int n;
3034 for (n = 0; n < 32; n++, value <<= 1) {
3035 if (value & HIGHORDER)
3036 break;
3038 return (n);
3043 * NAME: blkstol2(s64 nb)
3045 * FUNCTION: convert a block count to its log2 value. if the block
3046 * count is not a l2 multiple, it is rounded up to the next
3047 * larger l2 multiple.
3049 * PARAMETERS:
3050 * nb - number of blocks
3052 * RETURN VALUES:
3053 * log2 number of blocks
3055 static int blkstol2(s64 nb)
3057 int l2nb;
3058 s64 mask; /* meant to be signed */
3060 mask = (s64) 1 << (64 - 1);
3062 /* count the leading bits.
3064 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3065 /* leading bit found.
3067 if (nb & mask) {
3068 /* determine the l2 value.
3070 l2nb = (64 - 1) - l2nb;
3072 /* check if we need to round up.
3074 if (~mask & nb)
3075 l2nb++;
3077 return (l2nb);
3080 assert(0);
3081 return 0; /* fix compiler warning */
3086 * NAME: dbAllocBottomUp()
3088 * FUNCTION: alloc the specified block range from the working block
3089 * allocation map.
3091 * the blocks will be alloc from the working map one dmap
3092 * at a time.
3094 * PARAMETERS:
3095 * ip - pointer to in-core inode;
3096 * blkno - starting block number to be freed.
3097 * nblocks - number of blocks to be freed.
3099 * RETURN VALUES:
3100 * 0 - success
3101 * -EIO - i/o error
3103 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3105 struct metapage *mp;
3106 struct dmap *dp;
3107 int nb, rc;
3108 s64 lblkno, rem;
3109 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3110 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3112 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3114 /* block to be allocated better be within the mapsize. */
3115 ASSERT(nblocks <= bmp->db_mapsize - blkno);
3118 * allocate the blocks a dmap at a time.
3120 mp = NULL;
3121 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3122 /* release previous dmap if any */
3123 if (mp) {
3124 write_metapage(mp);
3127 /* get the buffer for the current dmap. */
3128 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3129 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3130 if (mp == NULL) {
3131 IREAD_UNLOCK(ipbmap);
3132 return -EIO;
3134 dp = (struct dmap *) mp->data;
3136 /* determine the number of blocks to be allocated from
3137 * this dmap.
3139 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3141 /* allocate the blocks. */
3142 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3143 release_metapage(mp);
3144 IREAD_UNLOCK(ipbmap);
3145 return (rc);
3149 /* write the last buffer. */
3150 write_metapage(mp);
3152 IREAD_UNLOCK(ipbmap);
3154 return (0);
3158 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3159 int nblocks)
3161 int rc;
3162 int dbitno, word, rembits, nb, nwords, wbitno, agno;
3163 s8 oldroot, *leaf;
3164 struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3166 /* save the current value of the root (i.e. maximum free string)
3167 * of the dmap tree.
3169 oldroot = tp->stree[ROOT];
3171 /* pick up a pointer to the leaves of the dmap tree */
3172 leaf = tp->stree + LEAFIND;
3174 /* determine the bit number and word within the dmap of the
3175 * starting block.
3177 dbitno = blkno & (BPERDMAP - 1);
3178 word = dbitno >> L2DBWORD;
3180 /* block range better be within the dmap */
3181 assert(dbitno + nblocks <= BPERDMAP);
3183 /* allocate the bits of the dmap's words corresponding to the block
3184 * range. not all bits of the first and last words may be contained
3185 * within the block range. if this is the case, we'll work against
3186 * those words (i.e. partial first and/or last) on an individual basis
3187 * (a single pass), allocating the bits of interest by hand and
3188 * updating the leaf corresponding to the dmap word. a single pass
3189 * will be used for all dmap words fully contained within the
3190 * specified range. within this pass, the bits of all fully contained
3191 * dmap words will be marked as free in a single shot and the leaves
3192 * will be updated. a single leaf may describe the free space of
3193 * multiple dmap words, so we may update only a subset of the actual
3194 * leaves corresponding to the dmap words of the block range.
3196 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3197 /* determine the bit number within the word and
3198 * the number of bits within the word.
3200 wbitno = dbitno & (DBWORD - 1);
3201 nb = min(rembits, DBWORD - wbitno);
3203 /* check if only part of a word is to be allocated.
3205 if (nb < DBWORD) {
3206 /* allocate (set to 1) the appropriate bits within
3207 * this dmap word.
3209 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3210 >> wbitno);
3212 word++;
3213 } else {
3214 /* one or more dmap words are fully contained
3215 * within the block range. determine how many
3216 * words and allocate (set to 1) the bits of these
3217 * words.
3219 nwords = rembits >> L2DBWORD;
3220 memset(&dp->wmap[word], (int) ONES, nwords * 4);
3222 /* determine how many bits */
3223 nb = nwords << L2DBWORD;
3224 word += nwords;
3228 /* update the free count for this dmap */
3229 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
3231 /* reconstruct summary tree */
3232 dbInitDmapTree(dp);
3234 BMAP_LOCK(bmp);
3236 /* if this allocation group is completely free,
3237 * update the highest active allocation group number
3238 * if this allocation group is the new max.
3240 agno = blkno >> bmp->db_agl2size;
3241 if (agno > bmp->db_maxag)
3242 bmp->db_maxag = agno;
3244 /* update the free count for the allocation group and map */
3245 bmp->db_agfree[agno] -= nblocks;
3246 bmp->db_nfree -= nblocks;
3248 BMAP_UNLOCK(bmp);
3250 /* if the root has not changed, done. */
3251 if (tp->stree[ROOT] == oldroot)
3252 return (0);
3254 /* root changed. bubble the change up to the dmap control pages.
3255 * if the adjustment of the upper level control pages fails,
3256 * backout the bit allocation (thus making everything consistent).
3258 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3259 dbFreeBits(bmp, dp, blkno, nblocks);
3261 return (rc);
3266 * NAME: dbExtendFS()
3268 * FUNCTION: extend bmap from blkno for nblocks;
3269 * dbExtendFS() updates bmap ready for dbAllocBottomUp();
3271 * L2
3273 * L1---------------------------------L1
3274 * | |
3275 * L0---------L0---------L0 L0---------L0---------L0
3276 * | | | | | |
3277 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
3278 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3280 * <---old---><----------------------------extend----------------------->
3282 int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3284 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3285 int nbperpage = sbi->nbperpage;
3286 int i, i0 = true, j, j0 = true, k, n;
3287 s64 newsize;
3288 s64 p;
3289 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3290 struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3291 struct dmap *dp;
3292 s8 *l0leaf, *l1leaf, *l2leaf;
3293 struct bmap *bmp = sbi->bmap;
3294 int agno, l2agsize, oldl2agsize;
3295 s64 ag_rem;
3297 newsize = blkno + nblocks;
3299 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3300 (long long) blkno, (long long) nblocks, (long long) newsize);
3303 * initialize bmap control page.
3305 * all the data in bmap control page should exclude
3306 * the mkfs hidden dmap page.
3309 /* update mapsize */
3310 bmp->db_mapsize = newsize;
3311 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3313 /* compute new AG size */
3314 l2agsize = dbGetL2AGSize(newsize);
3315 oldl2agsize = bmp->db_agl2size;
3317 bmp->db_agl2size = l2agsize;
3318 bmp->db_agsize = 1 << l2agsize;
3320 /* compute new number of AG */
3321 agno = bmp->db_numag;
3322 bmp->db_numag = newsize >> l2agsize;
3323 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3326 * reconfigure db_agfree[]
3327 * from old AG configuration to new AG configuration;
3329 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3330 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3331 * note: new AG size = old AG size * (2**x).
3333 if (l2agsize == oldl2agsize)
3334 goto extend;
3335 k = 1 << (l2agsize - oldl2agsize);
3336 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
3337 for (i = 0, n = 0; i < agno; n++) {
3338 bmp->db_agfree[n] = 0; /* init collection point */
3340 /* coalesce cotiguous k AGs; */
3341 for (j = 0; j < k && i < agno; j++, i++) {
3342 /* merge AGi to AGn */
3343 bmp->db_agfree[n] += bmp->db_agfree[i];
3346 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
3348 for (; n < MAXAG; n++)
3349 bmp->db_agfree[n] = 0;
3352 * update highest active ag number
3355 bmp->db_maxag = bmp->db_maxag / k;
3358 * extend bmap
3360 * update bit maps and corresponding level control pages;
3361 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3363 extend:
3364 /* get L2 page */
3365 p = BMAPBLKNO + nbperpage; /* L2 page */
3366 l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3367 if (!l2mp) {
3368 jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
3369 return -EIO;
3371 l2dcp = (struct dmapctl *) l2mp->data;
3373 /* compute start L1 */
3374 k = blkno >> L2MAXL1SIZE;
3375 l2leaf = l2dcp->stree + CTLLEAFIND + k;
3376 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
3379 * extend each L1 in L2
3381 for (; k < LPERCTL; k++, p += nbperpage) {
3382 /* get L1 page */
3383 if (j0) {
3384 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3385 l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3386 if (l1mp == NULL)
3387 goto errout;
3388 l1dcp = (struct dmapctl *) l1mp->data;
3390 /* compute start L0 */
3391 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3392 l1leaf = l1dcp->stree + CTLLEAFIND + j;
3393 p = BLKTOL0(blkno, sbi->l2nbperpage);
3394 j0 = false;
3395 } else {
3396 /* assign/init L1 page */
3397 l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3398 if (l1mp == NULL)
3399 goto errout;
3401 l1dcp = (struct dmapctl *) l1mp->data;
3403 /* compute start L0 */
3404 j = 0;
3405 l1leaf = l1dcp->stree + CTLLEAFIND;
3406 p += nbperpage; /* 1st L0 of L1.k */
3410 * extend each L0 in L1
3412 for (; j < LPERCTL; j++) {
3413 /* get L0 page */
3414 if (i0) {
3415 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3417 l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3418 if (l0mp == NULL)
3419 goto errout;
3420 l0dcp = (struct dmapctl *) l0mp->data;
3422 /* compute start dmap */
3423 i = (blkno & (MAXL0SIZE - 1)) >>
3424 L2BPERDMAP;
3425 l0leaf = l0dcp->stree + CTLLEAFIND + i;
3426 p = BLKTODMAP(blkno,
3427 sbi->l2nbperpage);
3428 i0 = false;
3429 } else {
3430 /* assign/init L0 page */
3431 l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3432 if (l0mp == NULL)
3433 goto errout;
3435 l0dcp = (struct dmapctl *) l0mp->data;
3437 /* compute start dmap */
3438 i = 0;
3439 l0leaf = l0dcp->stree + CTLLEAFIND;
3440 p += nbperpage; /* 1st dmap of L0.j */
3444 * extend each dmap in L0
3446 for (; i < LPERCTL; i++) {
3448 * reconstruct the dmap page, and
3449 * initialize corresponding parent L0 leaf
3451 if ((n = blkno & (BPERDMAP - 1))) {
3452 /* read in dmap page: */
3453 mp = read_metapage(ipbmap, p,
3454 PSIZE, 0);
3455 if (mp == NULL)
3456 goto errout;
3457 n = min(nblocks, (s64)BPERDMAP - n);
3458 } else {
3459 /* assign/init dmap page */
3460 mp = read_metapage(ipbmap, p,
3461 PSIZE, 0);
3462 if (mp == NULL)
3463 goto errout;
3465 n = min(nblocks, (s64)BPERDMAP);
3468 dp = (struct dmap *) mp->data;
3469 *l0leaf = dbInitDmap(dp, blkno, n);
3471 bmp->db_nfree += n;
3472 agno = le64_to_cpu(dp->start) >> l2agsize;
3473 bmp->db_agfree[agno] += n;
3475 write_metapage(mp);
3477 l0leaf++;
3478 p += nbperpage;
3480 blkno += n;
3481 nblocks -= n;
3482 if (nblocks == 0)
3483 break;
3484 } /* for each dmap in a L0 */
3487 * build current L0 page from its leaves, and
3488 * initialize corresponding parent L1 leaf
3490 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3491 write_metapage(l0mp);
3492 l0mp = NULL;
3494 if (nblocks)
3495 l1leaf++; /* continue for next L0 */
3496 else {
3497 /* more than 1 L0 ? */
3498 if (j > 0)
3499 break; /* build L1 page */
3500 else {
3501 /* summarize in global bmap page */
3502 bmp->db_maxfreebud = *l1leaf;
3503 release_metapage(l1mp);
3504 release_metapage(l2mp);
3505 goto finalize;
3508 } /* for each L0 in a L1 */
3511 * build current L1 page from its leaves, and
3512 * initialize corresponding parent L2 leaf
3514 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3515 write_metapage(l1mp);
3516 l1mp = NULL;
3518 if (nblocks)
3519 l2leaf++; /* continue for next L1 */
3520 else {
3521 /* more than 1 L1 ? */
3522 if (k > 0)
3523 break; /* build L2 page */
3524 else {
3525 /* summarize in global bmap page */
3526 bmp->db_maxfreebud = *l2leaf;
3527 release_metapage(l2mp);
3528 goto finalize;
3531 } /* for each L1 in a L2 */
3533 jfs_error(ipbmap->i_sb,
3534 "dbExtendFS: function has not returned as expected");
3535 errout:
3536 if (l0mp)
3537 release_metapage(l0mp);
3538 if (l1mp)
3539 release_metapage(l1mp);
3540 release_metapage(l2mp);
3541 return -EIO;
3544 * finalize bmap control page
3546 finalize:
3548 return 0;
3553 * dbFinalizeBmap()
3555 void dbFinalizeBmap(struct inode *ipbmap)
3557 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3558 int actags, inactags, l2nl;
3559 s64 ag_rem, actfree, inactfree, avgfree;
3560 int i, n;
3563 * finalize bmap control page
3565 //finalize:
3567 * compute db_agpref: preferred ag to allocate from
3568 * (the leftmost ag with average free space in it);
3570 //agpref:
3571 /* get the number of active ags and inacitve ags */
3572 actags = bmp->db_maxag + 1;
3573 inactags = bmp->db_numag - actags;
3574 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
3576 /* determine how many blocks are in the inactive allocation
3577 * groups. in doing this, we must account for the fact that
3578 * the rightmost group might be a partial group (i.e. file
3579 * system size is not a multiple of the group size).
3581 inactfree = (inactags && ag_rem) ?
3582 ((inactags - 1) << bmp->db_agl2size) + ag_rem
3583 : inactags << bmp->db_agl2size;
3585 /* determine how many free blocks are in the active
3586 * allocation groups plus the average number of free blocks
3587 * within the active ags.
3589 actfree = bmp->db_nfree - inactfree;
3590 avgfree = (u32) actfree / (u32) actags;
3592 /* if the preferred allocation group has not average free space.
3593 * re-establish the preferred group as the leftmost
3594 * group with average free space.
3596 if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3597 for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3598 bmp->db_agpref++) {
3599 if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3600 break;
3602 if (bmp->db_agpref >= bmp->db_numag) {
3603 jfs_error(ipbmap->i_sb,
3604 "cannot find ag with average freespace");
3609 * compute db_aglevel, db_agheigth, db_width, db_agstart:
3610 * an ag is covered in aglevel dmapctl summary tree,
3611 * at agheight level height (from leaf) with agwidth number of nodes
3612 * each, which starts at agstart index node of the smmary tree node
3613 * array;
3615 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3616 l2nl =
3617 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3618 bmp->db_agheigth = l2nl >> 1;
3619 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheigth << 1));
3620 for (i = 5 - bmp->db_agheigth, bmp->db_agstart = 0, n = 1; i > 0;
3621 i--) {
3622 bmp->db_agstart += n;
3623 n <<= 2;
3630 * NAME: dbInitDmap()/ujfs_idmap_page()
3632 * FUNCTION: initialize working/persistent bitmap of the dmap page
3633 * for the specified number of blocks:
3635 * at entry, the bitmaps had been initialized as free (ZEROS);
3636 * The number of blocks will only account for the actually
3637 * existing blocks. Blocks which don't actually exist in
3638 * the aggregate will be marked as allocated (ONES);
3640 * PARAMETERS:
3641 * dp - pointer to page of map
3642 * nblocks - number of blocks this page
3644 * RETURNS: NONE
3646 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3648 int blkno, w, b, r, nw, nb, i;
3650 /* starting block number within the dmap */
3651 blkno = Blkno & (BPERDMAP - 1);
3653 if (blkno == 0) {
3654 dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3655 dp->start = cpu_to_le64(Blkno);
3657 if (nblocks == BPERDMAP) {
3658 memset(&dp->wmap[0], 0, LPERDMAP * 4);
3659 memset(&dp->pmap[0], 0, LPERDMAP * 4);
3660 goto initTree;
3662 } else {
3663 dp->nblocks =
3664 cpu_to_le32(le32_to_cpu(dp->nblocks) + nblocks);
3665 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
3668 /* word number containing start block number */
3669 w = blkno >> L2DBWORD;
3672 * free the bits corresponding to the block range (ZEROS):
3673 * note: not all bits of the first and last words may be contained
3674 * within the block range.
3676 for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3677 /* number of bits preceding range to be freed in the word */
3678 b = blkno & (DBWORD - 1);
3679 /* number of bits to free in the word */
3680 nb = min(r, DBWORD - b);
3682 /* is partial word to be freed ? */
3683 if (nb < DBWORD) {
3684 /* free (set to 0) from the bitmap word */
3685 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3686 >> b));
3687 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3688 >> b));
3690 /* skip the word freed */
3691 w++;
3692 } else {
3693 /* free (set to 0) contiguous bitmap words */
3694 nw = r >> L2DBWORD;
3695 memset(&dp->wmap[w], 0, nw * 4);
3696 memset(&dp->pmap[w], 0, nw * 4);
3698 /* skip the words freed */
3699 nb = nw << L2DBWORD;
3700 w += nw;
3705 * mark bits following the range to be freed (non-existing
3706 * blocks) as allocated (ONES)
3709 if (blkno == BPERDMAP)
3710 goto initTree;
3712 /* the first word beyond the end of existing blocks */
3713 w = blkno >> L2DBWORD;
3715 /* does nblocks fall on a 32-bit boundary ? */
3716 b = blkno & (DBWORD - 1);
3717 if (b) {
3718 /* mark a partial word allocated */
3719 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3720 w++;
3723 /* set the rest of the words in the page to allocated (ONES) */
3724 for (i = w; i < LPERDMAP; i++)
3725 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3728 * init tree
3730 initTree:
3731 return (dbInitDmapTree(dp));
3736 * NAME: dbInitDmapTree()/ujfs_complete_dmap()
3738 * FUNCTION: initialize summary tree of the specified dmap:
3740 * at entry, bitmap of the dmap has been initialized;
3742 * PARAMETERS:
3743 * dp - dmap to complete
3744 * blkno - starting block number for this dmap
3745 * treemax - will be filled in with max free for this dmap
3747 * RETURNS: max free string at the root of the tree
3749 static int dbInitDmapTree(struct dmap * dp)
3751 struct dmaptree *tp;
3752 s8 *cp;
3753 int i;
3755 /* init fixed info of tree */
3756 tp = &dp->tree;
3757 tp->nleafs = cpu_to_le32(LPERDMAP);
3758 tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3759 tp->leafidx = cpu_to_le32(LEAFIND);
3760 tp->height = cpu_to_le32(4);
3761 tp->budmin = BUDMIN;
3763 /* init each leaf from corresponding wmap word:
3764 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3765 * bitmap word are allocated.
3767 cp = tp->stree + le32_to_cpu(tp->leafidx);
3768 for (i = 0; i < LPERDMAP; i++)
3769 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3771 /* build the dmap's binary buddy summary tree */
3772 return (dbInitTree(tp));
3777 * NAME: dbInitTree()/ujfs_adjtree()
3779 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
3781 * at entry, the leaves of the tree has been initialized
3782 * from corresponding bitmap word or root of summary tree
3783 * of the child control page;
3784 * configure binary buddy system at the leaf level, then
3785 * bubble up the values of the leaf nodes up the tree.
3787 * PARAMETERS:
3788 * cp - Pointer to the root of the tree
3789 * l2leaves- Number of leaf nodes as a power of 2
3790 * l2min - Number of blocks that can be covered by a leaf
3791 * as a power of 2
3793 * RETURNS: max free string at the root of the tree
3795 static int dbInitTree(struct dmaptree * dtp)
3797 int l2max, l2free, bsize, nextb, i;
3798 int child, parent, nparent;
3799 s8 *tp, *cp, *cp1;
3801 tp = dtp->stree;
3803 /* Determine the maximum free string possible for the leaves */
3804 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3807 * configure the leaf levevl into binary buddy system
3809 * Try to combine buddies starting with a buddy size of 1
3810 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3811 * can be combined if both buddies have a maximum free of l2min;
3812 * the combination will result in the left-most buddy leaf having
3813 * a maximum free of l2min+1.
3814 * After processing all buddies for a given size, process buddies
3815 * at the next higher buddy size (i.e. current size * 2) and
3816 * the next maximum free (current free + 1).
3817 * This continues until the maximum possible buddy combination
3818 * yields maximum free.
3820 for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3821 l2free++, bsize = nextb) {
3822 /* get next buddy size == current buddy pair size */
3823 nextb = bsize << 1;
3825 /* scan each adjacent buddy pair at current buddy size */
3826 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3827 i < le32_to_cpu(dtp->nleafs);
3828 i += nextb, cp += nextb) {
3829 /* coalesce if both adjacent buddies are max free */
3830 if (*cp == l2free && *(cp + bsize) == l2free) {
3831 *cp = l2free + 1; /* left take right */
3832 *(cp + bsize) = -1; /* right give left */
3838 * bubble summary information of leaves up the tree.
3840 * Starting at the leaf node level, the four nodes described by
3841 * the higher level parent node are compared for a maximum free and
3842 * this maximum becomes the value of the parent node.
3843 * when all lower level nodes are processed in this fashion then
3844 * move up to the next level (parent becomes a lower level node) and
3845 * continue the process for that level.
3847 for (child = le32_to_cpu(dtp->leafidx),
3848 nparent = le32_to_cpu(dtp->nleafs) >> 2;
3849 nparent > 0; nparent >>= 2, child = parent) {
3850 /* get index of 1st node of parent level */
3851 parent = (child - 1) >> 2;
3853 /* set the value of the parent node as the maximum
3854 * of the four nodes of the current level.
3856 for (i = 0, cp = tp + child, cp1 = tp + parent;
3857 i < nparent; i++, cp += 4, cp1++)
3858 *cp1 = TREEMAX(cp);
3861 return (*tp);
3866 * dbInitDmapCtl()
3868 * function: initialize dmapctl page
3870 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3871 { /* start leaf index not covered by range */
3872 s8 *cp;
3874 dcp->nleafs = cpu_to_le32(LPERCTL);
3875 dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3876 dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3877 dcp->height = cpu_to_le32(5);
3878 dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3881 * initialize the leaves of current level that were not covered
3882 * by the specified input block range (i.e. the leaves have no
3883 * low level dmapctl or dmap).
3885 cp = &dcp->stree[CTLLEAFIND + i];
3886 for (; i < LPERCTL; i++)
3887 *cp++ = NOFREE;
3889 /* build the dmap's binary buddy summary tree */
3890 return (dbInitTree((struct dmaptree *) dcp));
3895 * NAME: dbGetL2AGSize()/ujfs_getagl2size()
3897 * FUNCTION: Determine log2(allocation group size) from aggregate size
3899 * PARAMETERS:
3900 * nblocks - Number of blocks in aggregate
3902 * RETURNS: log2(allocation group size) in aggregate blocks
3904 static int dbGetL2AGSize(s64 nblocks)
3906 s64 sz;
3907 s64 m;
3908 int l2sz;
3910 if (nblocks < BPERDMAP * MAXAG)
3911 return (L2BPERDMAP);
3913 /* round up aggregate size to power of 2 */
3914 m = ((u64) 1 << (64 - 1));
3915 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3916 if (m & nblocks)
3917 break;
3920 sz = (s64) 1 << l2sz;
3921 if (sz < nblocks)
3922 l2sz += 1;
3924 /* agsize = roundupSize/max_number_of_ag */
3925 return (l2sz - L2MAXAG);
3930 * NAME: dbMapFileSizeToMapSize()
3932 * FUNCTION: compute number of blocks the block allocation map file
3933 * can cover from the map file size;
3935 * RETURNS: Number of blocks which can be covered by this block map file;
3939 * maximum number of map pages at each level including control pages
3941 #define MAXL0PAGES (1 + LPERCTL)
3942 #define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
3943 #define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
3946 * convert number of map pages to the zero origin top dmapctl level
3948 #define BMAPPGTOLEV(npages) \
3949 (((npages) <= 3 + MAXL0PAGES) ? 0 : \
3950 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
3952 s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3954 struct super_block *sb = ipbmap->i_sb;
3955 s64 nblocks;
3956 s64 npages, ndmaps;
3957 int level, i;
3958 int complete, factor;
3960 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
3961 npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
3962 level = BMAPPGTOLEV(npages);
3964 /* At each level, accumulate the number of dmap pages covered by
3965 * the number of full child levels below it;
3966 * repeat for the last incomplete child level.
3968 ndmaps = 0;
3969 npages--; /* skip the first global control page */
3970 /* skip higher level control pages above top level covered by map */
3971 npages -= (2 - level);
3972 npages--; /* skip top level's control page */
3973 for (i = level; i >= 0; i--) {
3974 factor =
3975 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
3976 complete = (u32) npages / factor;
3977 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
3978 ((i == 1) ? LPERCTL : 1));
3980 /* pages in last/incomplete child */
3981 npages = (u32) npages % factor;
3982 /* skip incomplete child's level control page */
3983 npages--;
3986 /* convert the number of dmaps into the number of blocks
3987 * which can be covered by the dmaps;
3989 nblocks = ndmaps << L2BPERDMAP;
3991 return (nblocks);