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
20 #include "jfs_incore.h"
21 #include "jfs_superblock.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
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) init_MUTEX(&bmp->db_bmaplock)
68 #define BMAP_LOCK(bmp) down(&bmp->db_bmaplock)
69 #define BMAP_UNLOCK(bmp) up(&bmp->db_bmaplock)
74 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
76 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
77 static void dbBackSplit(dmtree_t * tp, int leafno);
78 static void 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,
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,
85 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
87 int l2nb, s64 * results);
88 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
90 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
93 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
95 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
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 void dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
103 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
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,
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);
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 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
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.
157 * ipbmap - pointer to in-core inode for the block map.
161 * -ENOMEM - insufficient memory
164 int dbMount(struct inode *ipbmap)
167 struct dbmap_disk *dbmp_le;
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);
179 /* read the on-disk bmap descriptor. */
180 mp = read_metapage(ipbmap,
181 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
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
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.
235 * ipbmap - pointer to in-core inode for the block map.
241 int dbUnmount(struct inode *ipbmap, int mounterror)
243 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
245 if (!(mounterror || isReadOnly(ipbmap)))
249 * Invalidate the page cache buffers
251 truncate_inode_pages(ipbmap->i_mapping, 0);
253 /* free the memory for the in-memory bmap. */
262 int dbSync(struct inode *ipbmap)
264 struct dbmap_disk *dbmp_le;
265 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
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,
277 jfs_err("dbSync: read_metapage failed!");
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 */
303 * write out dirty pages of bmap
305 filemap_fdatawrite(ipbmap->i_mapping);
306 filemap_fdatawait(ipbmap->i_mapping);
308 ipbmap->i_state |= I_DIRTY;
309 diWriteSpecial(ipbmap, 0);
318 * FUNCTION: free the specified block range from the working block
321 * the blocks will be free from the working map one dmap
325 * ip - pointer to in-core inode;
326 * blkno - starting block number to be freed.
327 * nblocks - number of blocks to be freed.
333 int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
339 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
340 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
344 /* block to be freed better be within the mapsize. */
345 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
346 IREAD_UNLOCK(ipbmap);
347 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
348 (unsigned long long) blkno,
349 (unsigned long long) nblocks);
351 "dbFree: block to be freed is outside the map");
356 * free the blocks a dmap at a time.
359 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
360 /* release previous dmap if any */
365 /* get the buffer for the current dmap. */
366 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
367 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
369 IREAD_UNLOCK(ipbmap);
372 dp = (struct dmap *) mp->data;
374 /* determine the number of blocks to be freed from
377 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
379 /* free the blocks. */
380 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
381 release_metapage(mp);
382 IREAD_UNLOCK(ipbmap);
387 /* write the last buffer. */
390 IREAD_UNLOCK(ipbmap);
397 * NAME: dbUpdatePMap()
399 * FUNCTION: update the allocation state (free or allocate) of the
400 * specified block range in the persistent block allocation map.
402 * the blocks will be updated in the persistent map one
406 * ipbmap - pointer to in-core inode for the block map.
407 * free - TRUE if block range is to be freed from the persistent
408 * map; FALSE if it is to be allocated.
409 * blkno - starting block number of the range.
410 * nblocks - number of contiguous blocks in the range.
411 * tblk - transaction block;
418 dbUpdatePMap(struct inode *ipbmap,
419 int free, s64 blkno, s64 nblocks, struct tblock * tblk)
421 int nblks, dbitno, wbitno, rbits;
422 int word, nbits, nwords;
423 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
424 s64 lblkno, rem, lastlblkno;
429 int lsn, difft, diffp;
432 /* the blocks better be within the mapsize. */
433 if (blkno + nblocks > bmp->db_mapsize) {
434 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
435 (unsigned long long) blkno,
436 (unsigned long long) nblocks);
437 jfs_error(ipbmap->i_sb,
438 "dbUpdatePMap: blocks are outside the map");
442 /* compute delta of transaction lsn from log syncpt */
444 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
445 logdiff(difft, lsn, log);
448 * update the block state a dmap at a time.
452 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
453 /* get the buffer for the current dmap. */
454 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
455 if (lblkno != lastlblkno) {
460 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
464 metapage_wait_for_io(mp);
466 dp = (struct dmap *) mp->data;
468 /* determine the bit number and word within the dmap of
469 * the starting block. also determine how many blocks
470 * are to be updated within this dmap.
472 dbitno = blkno & (BPERDMAP - 1);
473 word = dbitno >> L2DBWORD;
474 nblks = min(rem, (s64)BPERDMAP - dbitno);
476 /* update the bits of the dmap words. the first and last
477 * words may only have a subset of their bits updated. if
478 * this is the case, we'll work against that word (i.e.
479 * partial first and/or last) only in a single pass. a
480 * single pass will also be used to update all words that
481 * are to have all their bits updated.
483 for (rbits = nblks; rbits > 0;
484 rbits -= nbits, dbitno += nbits) {
485 /* determine the bit number within the word and
486 * the number of bits within the word.
488 wbitno = dbitno & (DBWORD - 1);
489 nbits = min(rbits, DBWORD - wbitno);
491 /* check if only part of the word is to be updated. */
492 if (nbits < DBWORD) {
493 /* update (free or allocate) the bits
497 (ONES << (DBWORD - nbits) >> wbitno);
507 /* one or more words are to have all
508 * their bits updated. determine how
509 * many words and how many bits.
511 nwords = rbits >> L2DBWORD;
512 nbits = nwords << L2DBWORD;
514 /* update (free or allocate) the bits
518 memset(&dp->pmap[word], 0,
521 memset(&dp->pmap[word], (int) ONES,
531 if (lblkno == lastlblkno)
537 /* inherit older/smaller lsn */
538 logdiff(diffp, mp->lsn, log);
539 LOGSYNC_LOCK(log, flags);
543 /* move bp after tblock in logsync list */
544 list_move(&mp->synclist, &tblk->synclist);
547 /* inherit younger/larger clsn */
548 logdiff(difft, tblk->clsn, log);
549 logdiff(diffp, mp->clsn, log);
551 mp->clsn = tblk->clsn;
552 LOGSYNC_UNLOCK(log, flags);
557 /* insert bp after tblock in logsync list */
558 LOGSYNC_LOCK(log, flags);
561 list_add(&mp->synclist, &tblk->synclist);
563 mp->clsn = tblk->clsn;
564 LOGSYNC_UNLOCK(log, flags);
568 /* write the last buffer. */
580 * FUNCTION: find the preferred allocation group for new allocations.
582 * Within the allocation groups, we maintain a preferred
583 * allocation group which consists of a group with at least
584 * average free space. It is the preferred group that we target
585 * new inode allocation towards. The tie-in between inode
586 * allocation and block allocation occurs as we allocate the
587 * first (data) block of an inode and specify the inode (block)
588 * as the allocation hint for this block.
590 * We try to avoid having more than one open file growing in
591 * an allocation group, as this will lead to fragmentation.
592 * This differs from the old OS/2 method of trying to keep
593 * empty ags around for large allocations.
596 * ipbmap - pointer to in-core inode for the block map.
599 * the preferred allocation group number.
601 int dbNextAG(struct inode *ipbmap)
608 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
612 /* determine the average number of free blocks within the ags. */
613 avgfree = (u32)bmp->db_nfree / bmp->db_numag;
616 * if the current preferred ag does not have an active allocator
617 * and has at least average freespace, return it
619 agpref = bmp->db_agpref;
620 if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
621 (bmp->db_agfree[agpref] >= avgfree))
624 /* From the last preferred ag, find the next one with at least
625 * average free space.
627 for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
628 if (agpref == bmp->db_numag)
631 if (atomic_read(&bmp->db_active[agpref]))
632 /* open file is currently growing in this ag */
634 if (bmp->db_agfree[agpref] >= avgfree) {
635 /* Return this one */
636 bmp->db_agpref = agpref;
638 } else if (bmp->db_agfree[agpref] > hwm) {
639 /* Less than avg. freespace, but best so far */
640 hwm = bmp->db_agfree[agpref];
646 * If no inactive ag was found with average freespace, use the
650 bmp->db_agpref = next_best;
651 /* else leave db_agpref unchanged */
655 /* return the preferred group.
657 return (bmp->db_agpref);
663 * FUNCTION: attempt to allocate a specified number of contiguous free
664 * blocks from the working allocation block map.
666 * the block allocation policy uses hints and a multi-step
669 * for allocation requests smaller than the number of blocks
670 * per dmap, we first try to allocate the new blocks
671 * immediately following the hint. if these blocks are not
672 * available, we try to allocate blocks near the hint. if
673 * no blocks near the hint are available, we next try to
674 * allocate within the same dmap as contains the hint.
676 * if no blocks are available in the dmap or the allocation
677 * request is larger than the dmap size, we try to allocate
678 * within the same allocation group as contains the hint. if
679 * this does not succeed, we finally try to allocate anywhere
680 * within the aggregate.
682 * we also try to allocate anywhere within the aggregate for
683 * for allocation requests larger than the allocation group
684 * size or requests that specify no hint value.
687 * ip - pointer to in-core inode;
688 * hint - allocation hint.
689 * nblocks - number of contiguous blocks in the range.
690 * results - on successful return, set to the starting block number
691 * of the newly allocated contiguous range.
695 * -ENOSPC - insufficient disk resources
698 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
701 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
710 /* assert that nblocks is valid */
713 #ifdef _STILL_TO_PORT
714 /* DASD limit check F226941 */
715 if (OVER_LIMIT(ip, nblocks))
717 #endif /* _STILL_TO_PORT */
719 /* get the log2 number of blocks to be allocated.
720 * if the number of blocks is not a log2 multiple,
721 * it will be rounded up to the next log2 multiple.
723 l2nb = BLKSTOL2(nblocks);
725 bmp = JFS_SBI(ip->i_sb)->bmap;
727 //retry: /* serialize w.r.t.extendfs() */
728 mapSize = bmp->db_mapsize;
730 /* the hint should be within the map */
731 if (hint >= mapSize) {
732 jfs_error(ip->i_sb, "dbAlloc: the hint is outside the map");
736 /* if the number of blocks to be allocated is greater than the
737 * allocation group size, try to allocate anywhere.
739 if (l2nb > bmp->db_agl2size) {
742 rc = dbAllocAny(bmp, nblocks, l2nb, results);
748 * If no hint, let dbNextAG recommend an allocation group
753 /* we would like to allocate close to the hint. adjust the
754 * hint to the block following the hint since the allocators
755 * will start looking for free space starting at this point.
759 if (blkno >= bmp->db_mapsize)
762 agno = blkno >> bmp->db_agl2size;
764 /* check if blkno crosses over into a new allocation group.
765 * if so, check if we should allow allocations within this
768 if ((blkno & (bmp->db_agsize - 1)) == 0)
769 /* check if the AG is currenly being written to.
770 * if so, call dbNextAG() to find a non-busy
771 * AG with sufficient free space.
773 if (atomic_read(&bmp->db_active[agno]))
776 /* check if the allocation request size can be satisfied from a
777 * single dmap. if so, try to allocate from the dmap containing
778 * the hint using a tiered strategy.
780 if (nblocks <= BPERDMAP) {
783 /* get the buffer for the dmap containing the hint.
786 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
787 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
791 dp = (struct dmap *) mp->data;
793 /* first, try to satisfy the allocation request with the
794 * blocks beginning at the hint.
796 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
800 mark_metapage_dirty(mp);
803 release_metapage(mp);
807 writers = atomic_read(&bmp->db_active[agno]);
809 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
811 * Someone else is writing in this allocation
812 * group. To avoid fragmenting, try another ag
814 release_metapage(mp);
815 IREAD_UNLOCK(ipbmap);
819 /* next, try to satisfy the allocation request with blocks
823 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
826 mark_metapage_dirty(mp);
828 release_metapage(mp);
832 /* try to satisfy the allocation request with blocks within
833 * the same dmap as the hint.
835 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
838 mark_metapage_dirty(mp);
840 release_metapage(mp);
844 release_metapage(mp);
845 IREAD_UNLOCK(ipbmap);
848 /* try to satisfy the allocation request with blocks within
849 * the same allocation group as the hint.
852 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
855 IWRITE_UNLOCK(ipbmap);
860 * Let dbNextAG recommend a preferred allocation group
862 agno = dbNextAG(ipbmap);
865 /* Try to allocate within this allocation group. if that fails, try to
866 * allocate anywhere in the map.
868 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
869 rc = dbAllocAny(bmp, nblocks, l2nb, results);
872 IWRITE_UNLOCK(ipbmap);
877 IREAD_UNLOCK(ipbmap);
884 * NAME: dbAllocExact()
886 * FUNCTION: try to allocate the requested extent;
889 * ip - pointer to in-core inode;
890 * blkno - extent address;
891 * nblocks - extent length;
895 * -ENOSPC - insufficient disk resources
898 int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
901 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
902 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
910 * validate extent request:
912 * note: defragfs policy:
913 * max 64 blocks will be moved.
914 * allocation request size must be satisfied from a single dmap.
916 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
917 IREAD_UNLOCK(ipbmap);
921 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
922 /* the free space is no longer available */
923 IREAD_UNLOCK(ipbmap);
927 /* read in the dmap covering the extent */
928 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
929 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
931 IREAD_UNLOCK(ipbmap);
934 dp = (struct dmap *) mp->data;
936 /* try to allocate the requested extent */
937 rc = dbAllocNext(bmp, dp, blkno, nblocks);
939 IREAD_UNLOCK(ipbmap);
942 mark_metapage_dirty(mp);
944 release_metapage(mp);
953 * FUNCTION: attempt to extend a current allocation by a specified
956 * this routine attempts to satisfy the allocation request
957 * by first trying to extend the existing allocation in
958 * place by allocating the additional blocks as the blocks
959 * immediately following the current allocation. if these
960 * blocks are not available, this routine will attempt to
961 * allocate a new set of contiguous blocks large enough
962 * to cover the existing allocation plus the additional
963 * number of blocks required.
966 * ip - pointer to in-core inode requiring allocation.
967 * blkno - starting block of the current allocation.
968 * nblocks - number of contiguous blocks within the current
970 * addnblocks - number of blocks to add to the allocation.
971 * results - on successful return, set to the starting block number
972 * of the existing allocation if the existing allocation
973 * was extended in place or to a newly allocated contiguous
974 * range if the existing allocation could not be extended
979 * -ENOSPC - insufficient disk resources
983 dbReAlloc(struct inode *ip,
984 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
988 /* try to extend the allocation in place.
990 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
998 /* could not extend the allocation in place, so allocate a
999 * new set of blocks for the entire request (i.e. try to get
1000 * a range of contiguous blocks large enough to cover the
1001 * existing allocation plus the additional blocks.)
1004 (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
1011 * FUNCTION: attempt to extend a current allocation by a specified
1014 * this routine attempts to satisfy the allocation request
1015 * by first trying to extend the existing allocation in
1016 * place by allocating the additional blocks as the blocks
1017 * immediately following the current allocation.
1020 * ip - pointer to in-core inode requiring allocation.
1021 * blkno - starting block of the current allocation.
1022 * nblocks - number of contiguous blocks within the current
1024 * addnblocks - number of blocks to add to the allocation.
1028 * -ENOSPC - insufficient disk resources
1031 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1033 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1034 s64 lblkno, lastblkno, extblkno;
1036 struct metapage *mp;
1039 struct inode *ipbmap = sbi->ipbmap;
1043 * We don't want a non-aligned extent to cross a page boundary
1045 if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1046 (rel_block + nblocks + addnblocks > sbi->nbperpage))
1049 /* get the last block of the current allocation */
1050 lastblkno = blkno + nblocks - 1;
1052 /* determine the block number of the block following
1053 * the existing allocation.
1055 extblkno = lastblkno + 1;
1059 /* better be within the file system */
1061 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1062 IREAD_UNLOCK(ipbmap);
1064 "dbExtend: the block is outside the filesystem");
1068 /* we'll attempt to extend the current allocation in place by
1069 * allocating the additional blocks as the blocks immediately
1070 * following the current allocation. we only try to extend the
1071 * current allocation in place if the number of additional blocks
1072 * can fit into a dmap, the last block of the current allocation
1073 * is not the last block of the file system, and the start of the
1074 * inplace extension is not on an allocation group boundary.
1076 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1077 (extblkno & (bmp->db_agsize - 1)) == 0) {
1078 IREAD_UNLOCK(ipbmap);
1082 /* get the buffer for the dmap containing the first block
1085 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1086 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1088 IREAD_UNLOCK(ipbmap);
1092 dp = (struct dmap *) mp->data;
1094 /* try to allocate the blocks immediately following the
1095 * current allocation.
1097 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1099 IREAD_UNLOCK(ipbmap);
1101 /* were we successful ? */
1105 /* we were not successful */
1106 release_metapage(mp);
1114 * NAME: dbAllocNext()
1116 * FUNCTION: attempt to allocate the blocks of the specified block
1117 * range within a dmap.
1120 * bmp - pointer to bmap descriptor
1121 * dp - pointer to dmap.
1122 * blkno - starting block number of the range.
1123 * nblocks - number of contiguous free blocks of the range.
1127 * -ENOSPC - insufficient disk resources
1130 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1132 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1135 int dbitno, word, rembits, nb, nwords, wbitno, nw;
1140 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1141 jfs_error(bmp->db_ipbmap->i_sb,
1142 "dbAllocNext: Corrupt dmap page");
1146 /* pick up a pointer to the leaves of the dmap tree.
1148 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1150 /* determine the bit number and word within the dmap of the
1153 dbitno = blkno & (BPERDMAP - 1);
1154 word = dbitno >> L2DBWORD;
1156 /* check if the specified block range is contained within
1159 if (dbitno + nblocks > BPERDMAP)
1162 /* check if the starting leaf indicates that anything
1165 if (leaf[word] == NOFREE)
1168 /* check the dmaps words corresponding to block range to see
1169 * if the block range is free. not all bits of the first and
1170 * last words may be contained within the block range. if this
1171 * is the case, we'll work against those words (i.e. partial first
1172 * and/or last) on an individual basis (a single pass) and examine
1173 * the actual bits to determine if they are free. a single pass
1174 * will be used for all dmap words fully contained within the
1175 * specified range. within this pass, the leaves of the dmap
1176 * tree will be examined to determine if the blocks are free. a
1177 * single leaf may describe the free space of multiple dmap
1178 * words, so we may visit only a subset of the actual leaves
1179 * corresponding to the dmap words of the block range.
1181 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1182 /* determine the bit number within the word and
1183 * the number of bits within the word.
1185 wbitno = dbitno & (DBWORD - 1);
1186 nb = min(rembits, DBWORD - wbitno);
1188 /* check if only part of the word is to be examined.
1191 /* check if the bits are free.
1193 mask = (ONES << (DBWORD - nb) >> wbitno);
1194 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1199 /* one or more dmap words are fully contained
1200 * within the block range. determine how many
1201 * words and how many bits.
1203 nwords = rembits >> L2DBWORD;
1204 nb = nwords << L2DBWORD;
1206 /* now examine the appropriate leaves to determine
1207 * if the blocks are free.
1209 while (nwords > 0) {
1210 /* does the leaf describe any free space ?
1212 if (leaf[word] < BUDMIN)
1215 /* determine the l2 number of bits provided
1219 min((int)leaf[word], NLSTOL2BSZ(nwords));
1221 /* determine how many words were handled.
1223 nw = BUDSIZE(l2size, BUDMIN);
1231 /* allocate the blocks.
1233 return (dbAllocDmap(bmp, dp, blkno, nblocks));
1238 * NAME: dbAllocNear()
1240 * FUNCTION: attempt to allocate a number of contiguous free blocks near
1241 * a specified block (hint) within a dmap.
1243 * starting with the dmap leaf that covers the hint, we'll
1244 * check the next four contiguous leaves for sufficient free
1245 * space. if sufficient free space is found, we'll allocate
1246 * the desired free space.
1249 * bmp - pointer to bmap descriptor
1250 * dp - pointer to dmap.
1251 * blkno - block number to allocate near.
1252 * nblocks - actual number of contiguous free blocks desired.
1253 * l2nb - log2 number of contiguous free blocks desired.
1254 * results - on successful return, set to the starting block number
1255 * of the newly allocated range.
1259 * -ENOSPC - insufficient disk resources
1262 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1265 dbAllocNear(struct bmap * bmp,
1266 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1268 int word, lword, rc;
1271 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1272 jfs_error(bmp->db_ipbmap->i_sb,
1273 "dbAllocNear: Corrupt dmap page");
1277 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1279 /* determine the word within the dmap that holds the hint
1280 * (i.e. blkno). also, determine the last word in the dmap
1281 * that we'll include in our examination.
1283 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1284 lword = min(word + 4, LPERDMAP);
1286 /* examine the leaves for sufficient free space.
1288 for (; word < lword; word++) {
1289 /* does the leaf describe sufficient free space ?
1291 if (leaf[word] < l2nb)
1294 /* determine the block number within the file system
1295 * of the first block described by this dmap word.
1297 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1299 /* if not all bits of the dmap word are free, get the
1300 * starting bit number within the dmap word of the required
1301 * string of free bits and adjust the block number with the
1304 if (leaf[word] < BUDMIN)
1306 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1308 /* allocate the blocks.
1310 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1323 * FUNCTION: attempt to allocate the specified number of contiguous
1324 * free blocks within the specified allocation group.
1326 * unless the allocation group size is equal to the number
1327 * of blocks per dmap, the dmap control pages will be used to
1328 * find the required free space, if available. we start the
1329 * search at the highest dmap control page level which
1330 * distinctly describes the allocation group's free space
1331 * (i.e. the highest level at which the allocation group's
1332 * free space is not mixed in with that of any other group).
1333 * in addition, we start the search within this level at a
1334 * height of the dmapctl dmtree at which the nodes distinctly
1335 * describe the allocation group's free space. at this height,
1336 * the allocation group's free space may be represented by 1
1337 * or two sub-trees, depending on the allocation group size.
1338 * we search the top nodes of these subtrees left to right for
1339 * sufficient free space. if sufficient free space is found,
1340 * the subtree is searched to find the leftmost leaf that
1341 * has free space. once we have made it to the leaf, we
1342 * move the search to the next lower level dmap control page
1343 * corresponding to this leaf. we continue down the dmap control
1344 * pages until we find the dmap that contains or starts the
1345 * sufficient free space and we allocate at this dmap.
1347 * if the allocation group size is equal to the dmap size,
1348 * we'll start at the dmap corresponding to the allocation
1349 * group and attempt the allocation at this level.
1351 * the dmap control page search is also not performed if the
1352 * allocation group is completely free and we go to the first
1353 * dmap of the allocation group to do the allocation. this is
1354 * done because the allocation group may be part (not the first
1355 * part) of a larger binary buddy system, causing the dmap
1356 * control pages to indicate no free space (NOFREE) within
1357 * the allocation group.
1360 * bmp - pointer to bmap descriptor
1361 * agno - allocation group number.
1362 * nblocks - actual number of contiguous free blocks desired.
1363 * l2nb - log2 number of contiguous free blocks desired.
1364 * results - on successful return, set to the starting block number
1365 * of the newly allocated range.
1369 * -ENOSPC - insufficient disk resources
1372 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1375 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1377 struct metapage *mp;
1378 struct dmapctl *dcp;
1379 int rc, ti, i, k, m, n, agperlev;
1383 /* allocation request should not be for more than the
1384 * allocation group size.
1386 if (l2nb > bmp->db_agl2size) {
1387 jfs_error(bmp->db_ipbmap->i_sb,
1388 "dbAllocAG: allocation request is larger than the "
1389 "allocation group size");
1393 /* determine the starting block number of the allocation
1396 blkno = (s64) agno << bmp->db_agl2size;
1398 /* check if the allocation group size is the minimum allocation
1399 * group size or if the allocation group is completely free. if
1400 * the allocation group size is the minimum size of BPERDMAP (i.e.
1401 * 1 dmap), there is no need to search the dmap control page (below)
1402 * that fully describes the allocation group since the allocation
1403 * group is already fully described by a dmap. in this case, we
1404 * just call dbAllocCtl() to search the dmap tree and allocate the
1405 * required space if available.
1407 * if the allocation group is completely free, dbAllocCtl() is
1408 * also called to allocate the required space. this is done for
1409 * two reasons. first, it makes no sense searching the dmap control
1410 * pages for free space when we know that free space exists. second,
1411 * the dmap control pages may indicate that the allocation group
1412 * has no free space if the allocation group is part (not the first
1413 * part) of a larger binary buddy system.
1415 if (bmp->db_agsize == BPERDMAP
1416 || bmp->db_agfree[agno] == bmp->db_agsize) {
1417 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1418 if ((rc == -ENOSPC) &&
1419 (bmp->db_agfree[agno] == bmp->db_agsize)) {
1420 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1421 (unsigned long long) blkno,
1422 (unsigned long long) nblocks);
1423 jfs_error(bmp->db_ipbmap->i_sb,
1424 "dbAllocAG: dbAllocCtl failed in free AG");
1429 /* the buffer for the dmap control page that fully describes the
1432 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1433 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1436 dcp = (struct dmapctl *) mp->data;
1437 budmin = dcp->budmin;
1439 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1440 jfs_error(bmp->db_ipbmap->i_sb,
1441 "dbAllocAG: Corrupt dmapctl page");
1442 release_metapage(mp);
1446 /* search the subtree(s) of the dmap control page that describes
1447 * the allocation group, looking for sufficient free space. to begin,
1448 * determine how many allocation groups are represented in a dmap
1449 * control page at the control page level (i.e. L0, L1, L2) that
1450 * fully describes an allocation group. next, determine the starting
1451 * tree index of this allocation group within the control page.
1454 (1 << (L2LPERCTL - (bmp->db_agheigth << 1))) / bmp->db_agwidth;
1455 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1457 /* dmap control page trees fan-out by 4 and a single allocation
1458 * group may be described by 1 or 2 subtrees within the ag level
1459 * dmap control page, depending upon the ag size. examine the ag's
1460 * subtrees for sufficient free space, starting with the leftmost
1463 for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1464 /* is there sufficient free space ?
1466 if (l2nb > dcp->stree[ti])
1469 /* sufficient free space found in a subtree. now search down
1470 * the subtree to find the leftmost leaf that describes this
1473 for (k = bmp->db_agheigth; k > 0; k--) {
1474 for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1475 if (l2nb <= dcp->stree[m + n]) {
1481 jfs_error(bmp->db_ipbmap->i_sb,
1482 "dbAllocAG: failed descending stree");
1483 release_metapage(mp);
1488 /* determine the block number within the file system
1489 * that corresponds to this leaf.
1491 if (bmp->db_aglevel == 2)
1493 else if (bmp->db_aglevel == 1)
1494 blkno &= ~(MAXL1SIZE - 1);
1495 else /* bmp->db_aglevel == 0 */
1496 blkno &= ~(MAXL0SIZE - 1);
1499 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1501 /* release the buffer in preparation for going down
1502 * the next level of dmap control pages.
1504 release_metapage(mp);
1506 /* check if we need to continue to search down the lower
1507 * level dmap control pages. we need to if the number of
1508 * blocks required is less than maximum number of blocks
1509 * described at the next lower level.
1511 if (l2nb < budmin) {
1513 /* search the lower level dmap control pages to get
1514 * the starting block number of the the dmap that
1515 * contains or starts off the free space.
1518 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1520 if (rc == -ENOSPC) {
1521 jfs_error(bmp->db_ipbmap->i_sb,
1522 "dbAllocAG: control page "
1530 /* allocate the blocks.
1532 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1533 if (rc == -ENOSPC) {
1534 jfs_error(bmp->db_ipbmap->i_sb,
1535 "dbAllocAG: unable to allocate blocks");
1541 /* no space in the allocation group. release the buffer and
1544 release_metapage(mp);
1551 * NAME: dbAllocAny()
1553 * FUNCTION: attempt to allocate the specified number of contiguous
1554 * free blocks anywhere in the file system.
1556 * dbAllocAny() attempts to find the sufficient free space by
1557 * searching down the dmap control pages, starting with the
1558 * highest level (i.e. L0, L1, L2) control page. if free space
1559 * large enough to satisfy the desired free space is found, the
1560 * desired free space is allocated.
1563 * bmp - pointer to bmap descriptor
1564 * nblocks - actual number of contiguous free blocks desired.
1565 * l2nb - log2 number of contiguous free blocks desired.
1566 * results - on successful return, set to the starting block number
1567 * of the newly allocated range.
1571 * -ENOSPC - insufficient disk resources
1574 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1576 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1581 /* starting with the top level dmap control page, search
1582 * down the dmap control levels for sufficient free space.
1583 * if free space is found, dbFindCtl() returns the starting
1584 * block number of the dmap that contains or starts off the
1585 * range of free space.
1587 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1590 /* allocate the blocks.
1592 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1593 if (rc == -ENOSPC) {
1594 jfs_error(bmp->db_ipbmap->i_sb,
1595 "dbAllocAny: unable to allocate blocks");
1605 * FUNCTION: starting at a specified dmap control page level and block
1606 * number, search down the dmap control levels for a range of
1607 * contiguous free blocks large enough to satisfy an allocation
1608 * request for the specified number of free blocks.
1610 * if sufficient contiguous free blocks are found, this routine
1611 * returns the starting block number within a dmap page that
1612 * contains or starts a range of contiqious free blocks that
1613 * is sufficient in size.
1616 * bmp - pointer to bmap descriptor
1617 * level - starting dmap control page level.
1618 * l2nb - log2 number of contiguous free blocks desired.
1619 * *blkno - on entry, starting block number for conducting the search.
1620 * on successful return, the first block within a dmap page
1621 * that contains or starts a range of contiguous free blocks.
1625 * -ENOSPC - insufficient disk resources
1628 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1630 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1632 int rc, leafidx, lev;
1634 struct dmapctl *dcp;
1636 struct metapage *mp;
1638 /* starting at the specified dmap control page level and block
1639 * number, search down the dmap control levels for the starting
1640 * block number of a dmap page that contains or starts off
1641 * sufficient free blocks.
1643 for (lev = level, b = *blkno; lev >= 0; lev--) {
1644 /* get the buffer of the dmap control page for the block
1645 * number and level (i.e. L0, L1, L2).
1647 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1648 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1651 dcp = (struct dmapctl *) mp->data;
1652 budmin = dcp->budmin;
1654 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1655 jfs_error(bmp->db_ipbmap->i_sb,
1656 "dbFindCtl: Corrupt dmapctl page");
1657 release_metapage(mp);
1661 /* search the tree within the dmap control page for
1662 * sufficent free space. if sufficient free space is found,
1663 * dbFindLeaf() returns the index of the leaf at which
1664 * free space was found.
1666 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1668 /* release the buffer.
1670 release_metapage(mp);
1676 jfs_error(bmp->db_ipbmap->i_sb,
1677 "dbFindCtl: dmap inconsistent");
1683 /* adjust the block number to reflect the location within
1684 * the dmap control page (i.e. the leaf) at which free
1687 b += (((s64) leafidx) << budmin);
1689 /* we stop the search at this dmap control page level if
1690 * the number of blocks required is greater than or equal
1691 * to the maximum number of blocks described at the next
1704 * NAME: dbAllocCtl()
1706 * FUNCTION: attempt to allocate a specified number of contiguous
1707 * blocks starting within a specific dmap.
1709 * this routine is called by higher level routines that search
1710 * the dmap control pages above the actual dmaps for contiguous
1711 * free space. the result of successful searches by these
1712 * routines are the starting block numbers within dmaps, with
1713 * the dmaps themselves containing the desired contiguous free
1714 * space or starting a contiguous free space of desired size
1715 * that is made up of the blocks of one or more dmaps. these
1716 * calls should not fail due to insufficent resources.
1718 * this routine is called in some cases where it is not known
1719 * whether it will fail due to insufficient resources. more
1720 * specifically, this occurs when allocating from an allocation
1721 * group whose size is equal to the number of blocks per dmap.
1722 * in this case, the dmap control pages are not examined prior
1723 * to calling this routine (to save pathlength) and the call
1726 * for a request size that fits within a dmap, this routine relies
1727 * upon the dmap's dmtree to find the requested contiguous free
1728 * space. for request sizes that are larger than a dmap, the
1729 * requested free space will start at the first block of the
1730 * first dmap (i.e. blkno).
1733 * bmp - pointer to bmap descriptor
1734 * nblocks - actual number of contiguous free blocks to allocate.
1735 * l2nb - log2 number of contiguous free blocks to allocate.
1736 * blkno - starting block number of the dmap to start the allocation
1738 * results - on successful return, set to the starting block number
1739 * of the newly allocated range.
1743 * -ENOSPC - insufficient disk resources
1746 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1749 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1753 struct metapage *mp;
1756 /* check if the allocation request is confined to a single dmap.
1758 if (l2nb <= L2BPERDMAP) {
1759 /* get the buffer for the dmap.
1761 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1762 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1765 dp = (struct dmap *) mp->data;
1767 /* try to allocate the blocks.
1769 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1771 mark_metapage_dirty(mp);
1773 release_metapage(mp);
1778 /* allocation request involving multiple dmaps. it must start on
1781 assert((blkno & (BPERDMAP - 1)) == 0);
1783 /* allocate the blocks dmap by dmap.
1785 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1786 /* get the buffer for the dmap.
1788 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1789 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1794 dp = (struct dmap *) mp->data;
1796 /* the dmap better be all free.
1798 if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1799 release_metapage(mp);
1800 jfs_error(bmp->db_ipbmap->i_sb,
1801 "dbAllocCtl: the dmap is not all free");
1806 /* determine how many blocks to allocate from this dmap.
1808 nb = min(n, (s64)BPERDMAP);
1810 /* allocate the blocks from the dmap.
1812 if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1813 release_metapage(mp);
1817 /* write the buffer.
1822 /* set the results (starting block number) and return.
1827 /* something failed in handling an allocation request involving
1828 * multiple dmaps. we'll try to clean up by backing out any
1829 * allocation that has already happened for this request. if
1830 * we fail in backing out the allocation, we'll mark the file
1831 * system to indicate that blocks have been leaked.
1835 /* try to backout the allocations dmap by dmap.
1837 for (n = nblocks - n, b = blkno; n > 0;
1838 n -= BPERDMAP, b += BPERDMAP) {
1839 /* get the buffer for this dmap.
1841 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1842 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1844 /* could not back out. mark the file system
1845 * to indicate that we have leaked blocks.
1847 jfs_error(bmp->db_ipbmap->i_sb,
1848 "dbAllocCtl: I/O Error: Block Leakage.");
1851 dp = (struct dmap *) mp->data;
1853 /* free the blocks is this dmap.
1855 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1856 /* could not back out. mark the file system
1857 * to indicate that we have leaked blocks.
1859 release_metapage(mp);
1860 jfs_error(bmp->db_ipbmap->i_sb,
1861 "dbAllocCtl: Block Leakage.");
1865 /* write the buffer.
1875 * NAME: dbAllocDmapLev()
1877 * FUNCTION: attempt to allocate a specified number of contiguous blocks
1878 * from a specified dmap.
1880 * this routine checks if the contiguous blocks are available.
1881 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1885 * mp - pointer to bmap descriptor
1886 * dp - pointer to dmap to attempt to allocate blocks from.
1887 * l2nb - log2 number of contiguous block desired.
1888 * nblocks - actual number of contiguous block desired.
1889 * results - on successful return, set to the starting block number
1890 * of the newly allocated range.
1894 * -ENOSPC - insufficient disk resources
1897 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1898 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1901 dbAllocDmapLev(struct bmap * bmp,
1902 struct dmap * dp, int nblocks, int l2nb, s64 * results)
1907 /* can't be more than a dmaps worth of blocks */
1908 assert(l2nb <= L2BPERDMAP);
1910 /* search the tree within the dmap page for sufficient
1911 * free space. if sufficient free space is found, dbFindLeaf()
1912 * returns the index of the leaf at which free space was found.
1914 if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1917 /* determine the block number within the file system corresponding
1918 * to the leaf at which free space was found.
1920 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1922 /* if not all bits of the dmap word are free, get the starting
1923 * bit number within the dmap word of the required string of free
1924 * bits and adjust the block number with this value.
1926 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1927 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1929 /* allocate the blocks */
1930 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1938 * NAME: dbAllocDmap()
1940 * FUNCTION: adjust the disk allocation map to reflect the allocation
1941 * of a specified block range within a dmap.
1943 * this routine allocates the specified blocks from the dmap
1944 * through a call to dbAllocBits(). if the allocation of the
1945 * block range causes the maximum string of free blocks within
1946 * the dmap to change (i.e. the value of the root of the dmap's
1947 * dmtree), this routine will cause this change to be reflected
1948 * up through the appropriate levels of the dmap control pages
1949 * by a call to dbAdjCtl() for the L0 dmap control page that
1953 * bmp - pointer to bmap descriptor
1954 * dp - pointer to dmap to allocate the block range from.
1955 * blkno - starting block number of the block to be allocated.
1956 * nblocks - number of blocks to be allocated.
1962 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
1964 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
1970 /* save the current value of the root (i.e. maximum free string)
1973 oldroot = dp->tree.stree[ROOT];
1975 /* allocate the specified (blocks) bits */
1976 dbAllocBits(bmp, dp, blkno, nblocks);
1978 /* if the root has not changed, done. */
1979 if (dp->tree.stree[ROOT] == oldroot)
1982 /* root changed. bubble the change up to the dmap control pages.
1983 * if the adjustment of the upper level control pages fails,
1984 * backout the bit allocation (thus making everything consistent).
1986 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
1987 dbFreeBits(bmp, dp, blkno, nblocks);
1994 * NAME: dbFreeDmap()
1996 * FUNCTION: adjust the disk allocation map to reflect the allocation
1997 * of a specified block range within a dmap.
1999 * this routine frees the specified blocks from the dmap through
2000 * a call to dbFreeBits(). if the deallocation of the block range
2001 * causes the maximum string of free blocks within the dmap to
2002 * change (i.e. the value of the root of the dmap's dmtree), this
2003 * routine will cause this change to be reflected up through the
2004 * appropriate levels of the dmap control pages by a call to
2005 * dbAdjCtl() for the L0 dmap control page that covers this dmap.
2008 * bmp - pointer to bmap descriptor
2009 * dp - pointer to dmap to free the block range from.
2010 * blkno - starting block number of the block to be freed.
2011 * nblocks - number of blocks to be freed.
2017 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2019 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2025 /* save the current value of the root (i.e. maximum free string)
2028 oldroot = dp->tree.stree[ROOT];
2030 /* free the specified (blocks) bits */
2031 dbFreeBits(bmp, dp, blkno, nblocks);
2033 /* if the root has not changed, done. */
2034 if (dp->tree.stree[ROOT] == oldroot)
2037 /* root changed. bubble the change up to the dmap control pages.
2038 * if the adjustment of the upper level control pages fails,
2039 * backout the deallocation.
2041 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2042 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2044 /* as part of backing out the deallocation, we will have
2045 * to back split the dmap tree if the deallocation caused
2046 * the freed blocks to become part of a larger binary buddy
2049 if (dp->tree.stree[word] == NOFREE)
2050 dbBackSplit((dmtree_t *) & dp->tree, word);
2052 dbAllocBits(bmp, dp, blkno, nblocks);
2060 * NAME: dbAllocBits()
2062 * FUNCTION: allocate a specified block range from a dmap.
2064 * this routine updates the dmap to reflect the working
2065 * state allocation of the specified block range. it directly
2066 * updates the bits of the working map and causes the adjustment
2067 * of the binary buddy system described by the dmap's dmtree
2068 * leaves to reflect the bits allocated. it also causes the
2069 * dmap's dmtree, as a whole, to reflect the allocated range.
2072 * bmp - pointer to bmap descriptor
2073 * dp - pointer to dmap to allocate bits from.
2074 * blkno - starting block number of the bits to be allocated.
2075 * nblocks - number of bits to be allocated.
2077 * RETURN VALUES: none
2079 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2081 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2084 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2085 dmtree_t *tp = (dmtree_t *) & dp->tree;
2089 /* pick up a pointer to the leaves of the dmap tree */
2090 leaf = dp->tree.stree + LEAFIND;
2092 /* determine the bit number and word within the dmap of the
2095 dbitno = blkno & (BPERDMAP - 1);
2096 word = dbitno >> L2DBWORD;
2098 /* block range better be within the dmap */
2099 assert(dbitno + nblocks <= BPERDMAP);
2101 /* allocate the bits of the dmap's words corresponding to the block
2102 * range. not all bits of the first and last words may be contained
2103 * within the block range. if this is the case, we'll work against
2104 * those words (i.e. partial first and/or last) on an individual basis
2105 * (a single pass), allocating the bits of interest by hand and
2106 * updating the leaf corresponding to the dmap word. a single pass
2107 * will be used for all dmap words fully contained within the
2108 * specified range. within this pass, the bits of all fully contained
2109 * dmap words will be marked as free in a single shot and the leaves
2110 * will be updated. a single leaf may describe the free space of
2111 * multiple dmap words, so we may update only a subset of the actual
2112 * leaves corresponding to the dmap words of the block range.
2114 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2115 /* determine the bit number within the word and
2116 * the number of bits within the word.
2118 wbitno = dbitno & (DBWORD - 1);
2119 nb = min(rembits, DBWORD - wbitno);
2121 /* check if only part of a word is to be allocated.
2124 /* allocate (set to 1) the appropriate bits within
2127 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2130 /* update the leaf for this dmap word. in addition
2131 * to setting the leaf value to the binary buddy max
2132 * of the updated dmap word, dbSplit() will split
2133 * the binary system of the leaves if need be.
2135 dbSplit(tp, word, BUDMIN,
2136 dbMaxBud((u8 *) & dp->wmap[word]));
2140 /* one or more dmap words are fully contained
2141 * within the block range. determine how many
2142 * words and allocate (set to 1) the bits of these
2145 nwords = rembits >> L2DBWORD;
2146 memset(&dp->wmap[word], (int) ONES, nwords * 4);
2148 /* determine how many bits.
2150 nb = nwords << L2DBWORD;
2152 /* now update the appropriate leaves to reflect
2153 * the allocated words.
2155 for (; nwords > 0; nwords -= nw) {
2156 if (leaf[word] < BUDMIN) {
2157 jfs_error(bmp->db_ipbmap->i_sb,
2158 "dbAllocBits: leaf page "
2163 /* determine what the leaf value should be
2164 * updated to as the minimum of the l2 number
2165 * of bits being allocated and the l2 number
2166 * of bits currently described by this leaf.
2168 size = min((int)leaf[word], NLSTOL2BSZ(nwords));
2170 /* update the leaf to reflect the allocation.
2171 * in addition to setting the leaf value to
2172 * NOFREE, dbSplit() will split the binary
2173 * system of the leaves to reflect the current
2174 * allocation (size).
2176 dbSplit(tp, word, size, NOFREE);
2178 /* get the number of dmap words handled */
2179 nw = BUDSIZE(size, BUDMIN);
2185 /* update the free count for this dmap */
2186 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
2190 /* if this allocation group is completely free,
2191 * update the maximum allocation group number if this allocation
2192 * group is the new max.
2194 agno = blkno >> bmp->db_agl2size;
2195 if (agno > bmp->db_maxag)
2196 bmp->db_maxag = agno;
2198 /* update the free count for the allocation group and map */
2199 bmp->db_agfree[agno] -= nblocks;
2200 bmp->db_nfree -= nblocks;
2207 * NAME: dbFreeBits()
2209 * FUNCTION: free a specified block range from a dmap.
2211 * this routine updates the dmap to reflect the working
2212 * state allocation of the specified block range. it directly
2213 * updates the bits of the working map and causes the adjustment
2214 * of the binary buddy system described by the dmap's dmtree
2215 * leaves to reflect the bits freed. it also causes the dmap's
2216 * dmtree, as a whole, to reflect the deallocated range.
2219 * bmp - pointer to bmap descriptor
2220 * dp - pointer to dmap to free bits from.
2221 * blkno - starting block number of the bits to be freed.
2222 * nblocks - number of bits to be freed.
2224 * RETURN VALUES: none
2226 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2228 static void dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2231 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2232 dmtree_t *tp = (dmtree_t *) & dp->tree;
2235 /* determine the bit number and word within the dmap of the
2238 dbitno = blkno & (BPERDMAP - 1);
2239 word = dbitno >> L2DBWORD;
2241 /* block range better be within the dmap.
2243 assert(dbitno + nblocks <= BPERDMAP);
2245 /* free the bits of the dmaps words corresponding to the block range.
2246 * not all bits of the first and last words may be contained within
2247 * the block range. if this is the case, we'll work against those
2248 * words (i.e. partial first and/or last) on an individual basis
2249 * (a single pass), freeing the bits of interest by hand and updating
2250 * the leaf corresponding to the dmap word. a single pass will be used
2251 * for all dmap words fully contained within the specified range.
2252 * within this pass, the bits of all fully contained dmap words will
2253 * be marked as free in a single shot and the leaves will be updated. a
2254 * single leaf may describe the free space of multiple dmap words,
2255 * so we may update only a subset of the actual leaves corresponding
2256 * to the dmap words of the block range.
2258 * dbJoin() is used to update leaf values and will join the binary
2259 * buddy system of the leaves if the new leaf values indicate this
2262 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2263 /* determine the bit number within the word and
2264 * the number of bits within the word.
2266 wbitno = dbitno & (DBWORD - 1);
2267 nb = min(rembits, DBWORD - wbitno);
2269 /* check if only part of a word is to be freed.
2272 /* free (zero) the appropriate bits within this
2276 cpu_to_le32(~(ONES << (DBWORD - nb)
2279 /* update the leaf for this dmap word.
2282 dbMaxBud((u8 *) & dp->wmap[word]));
2286 /* one or more dmap words are fully contained
2287 * within the block range. determine how many
2288 * words and free (zero) the bits of these words.
2290 nwords = rembits >> L2DBWORD;
2291 memset(&dp->wmap[word], 0, nwords * 4);
2293 /* determine how many bits.
2295 nb = nwords << L2DBWORD;
2297 /* now update the appropriate leaves to reflect
2300 for (; nwords > 0; nwords -= nw) {
2301 /* determine what the leaf value should be
2302 * updated to as the minimum of the l2 number
2303 * of bits being freed and the l2 (max) number
2304 * of bits that can be described by this leaf.
2308 (word, L2LPERDMAP, BUDMIN),
2309 NLSTOL2BSZ(nwords));
2313 dbJoin(tp, word, size);
2315 /* get the number of dmap words handled.
2317 nw = BUDSIZE(size, BUDMIN);
2323 /* update the free count for this dmap.
2325 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
2329 /* update the free count for the allocation group and
2332 agno = blkno >> bmp->db_agl2size;
2333 bmp->db_nfree += nblocks;
2334 bmp->db_agfree[agno] += nblocks;
2336 /* check if this allocation group is not completely free and
2337 * if it is currently the maximum (rightmost) allocation group.
2338 * if so, establish the new maximum allocation group number by
2339 * searching left for the first allocation group with allocation.
2341 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2342 (agno == bmp->db_numag - 1 &&
2343 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2344 while (bmp->db_maxag > 0) {
2346 if (bmp->db_agfree[bmp->db_maxag] !=
2351 /* re-establish the allocation group preference if the
2352 * current preference is right of the maximum allocation
2355 if (bmp->db_agpref > bmp->db_maxag)
2356 bmp->db_agpref = bmp->db_maxag;
2366 * FUNCTION: adjust a dmap control page at a specified level to reflect
2367 * the change in a lower level dmap or dmap control page's
2368 * maximum string of free blocks (i.e. a change in the root
2369 * of the lower level object's dmtree) due to the allocation
2370 * or deallocation of a range of blocks with a single dmap.
2372 * on entry, this routine is provided with the new value of
2373 * the lower level dmap or dmap control page root and the
2374 * starting block number of the block range whose allocation
2375 * or deallocation resulted in the root change. this range
2376 * is respresented by a single leaf of the current dmapctl
2377 * and the leaf will be updated with this value, possibly
2378 * causing a binary buddy system within the leaves to be
2379 * split or joined. the update may also cause the dmapctl's
2380 * dmtree to be updated.
2382 * if the adjustment of the dmap control page, itself, causes its
2383 * root to change, this change will be bubbled up to the next dmap
2384 * control level by a recursive call to this routine, specifying
2385 * the new root value and the next dmap control page level to
2388 * bmp - pointer to bmap descriptor
2389 * blkno - the first block of a block range within a dmap. it is
2390 * the allocation or deallocation of this block range that
2391 * requires the dmap control page to be adjusted.
2392 * newval - the new value of the lower level dmap or dmap control
2394 * alloc - TRUE if adjustment is due to an allocation.
2395 * level - current level of dmap control page (i.e. L0, L1, L2) to
2402 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2405 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2407 struct metapage *mp;
2411 struct dmapctl *dcp;
2414 /* get the buffer for the dmap control page for the specified
2415 * block number and control page level.
2417 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2418 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2421 dcp = (struct dmapctl *) mp->data;
2423 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2424 jfs_error(bmp->db_ipbmap->i_sb,
2425 "dbAdjCtl: Corrupt dmapctl page");
2426 release_metapage(mp);
2430 /* determine the leaf number corresponding to the block and
2431 * the index within the dmap control tree.
2433 leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2434 ti = leafno + le32_to_cpu(dcp->leafidx);
2436 /* save the current leaf value and the current root level (i.e.
2437 * maximum l2 free string described by this dmapctl).
2439 oldval = dcp->stree[ti];
2440 oldroot = dcp->stree[ROOT];
2442 /* check if this is a control page update for an allocation.
2443 * if so, update the leaf to reflect the new leaf value using
2444 * dbSplit(); otherwise (deallocation), use dbJoin() to udpate
2445 * the leaf with the new value. in addition to updating the
2446 * leaf, dbSplit() will also split the binary buddy system of
2447 * the leaves, if required, and bubble new values within the
2448 * dmapctl tree, if required. similarly, dbJoin() will join
2449 * the binary buddy system of leaves and bubble new values up
2450 * the dmapctl tree as required by the new leaf value.
2453 /* check if we are in the middle of a binary buddy
2454 * system. this happens when we are performing the
2455 * first allocation out of an allocation group that
2456 * is part (not the first part) of a larger binary
2457 * buddy system. if we are in the middle, back split
2458 * the system prior to calling dbSplit() which assumes
2459 * that it is at the front of a binary buddy system.
2461 if (oldval == NOFREE) {
2462 dbBackSplit((dmtree_t *) dcp, leafno);
2463 oldval = dcp->stree[ti];
2465 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2467 dbJoin((dmtree_t *) dcp, leafno, newval);
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
2486 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2488 /* something went wrong in bubbling up the new
2489 * root value, so backout the changes to the
2490 * current dmap control page.
2493 dbJoin((dmtree_t *) dcp, leafno,
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 *)
2505 dbSplit((dmtree_t *) dcp, leafno,
2506 dcp->budmin, oldval);
2509 /* release the buffer and return the error.
2511 release_metapage(mp);
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.
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.
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)
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.
2586 /* adjust the dmap tree to reflect the specified leaf's new
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.
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 void dbBackSplit(dmtree_t * tp, int leafno)
2622 int budsz, bud, w, bsz, size;
2624 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2626 /* leaf should be part (not first part) of a binary
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.
2639 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
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);
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 assert(bsz < le32_to_cpu(tp->dmt_nleafs));
2657 /* determine the buddy.
2661 /* check if this buddy is the start of the system.
2663 if (leaf[bud] != NOFREE) {
2664 /* split the leaf at the start of the
2667 cursz = leaf[bud] - 1;
2668 dbSplit(tp, bud, cursz, cursz);
2674 assert(leaf[leafno] == size);
2681 * FUNCTION: update the leaf of a dmtree with a new value, joining
2682 * the leaf with other leaves of the dmtree into a multi-leaf
2683 * binary buddy system, as required.
2686 * tp - pointer to the tree containing the leaf.
2687 * leafno - the number of the leaf to be updated.
2688 * newval - the new value for the leaf.
2690 * RETURN VALUES: none
2692 static void dbJoin(dmtree_t * tp, int leafno, int newval)
2697 /* can the new leaf value require a join with other leaves ?
2699 if (newval >= tp->dmt_budmin) {
2700 /* pickup a pointer to the leaves of the tree.
2702 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2704 /* try to join the specified leaf into a large binary
2705 * buddy system. the join proceeds by attempting to join
2706 * the specified leafno with its buddy (leaf) at new value.
2707 * if the join occurs, we attempt to join the left leaf
2708 * of the joined buddies with its buddy at new value + 1.
2709 * we continue to join until we find a buddy that cannot be
2710 * joined (does not have a value equal to the size of the
2711 * last join) or until all leaves have been joined into a
2714 * get the buddy size (number of words covered) of
2717 budsz = BUDSIZE(newval, tp->dmt_budmin);
2721 while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2722 /* get the buddy leaf.
2724 buddy = leafno ^ budsz;
2726 /* if the leaf's new value is greater than its
2727 * buddy's value, we join no more.
2729 if (newval > leaf[buddy])
2732 assert(newval == leaf[buddy]);
2734 /* check which (leafno or buddy) is the left buddy.
2735 * the left buddy gets to claim the blocks resulting
2736 * from the join while the right gets to claim none.
2737 * the left buddy is also eligable to participate in
2738 * a join at the next higher level while the right
2742 if (leafno < buddy) {
2743 /* leafno is the left buddy.
2745 dbAdjTree(tp, buddy, NOFREE);
2747 /* buddy is the left buddy and becomes
2750 dbAdjTree(tp, leafno, NOFREE);
2754 /* on to try the next join.
2761 /* update the leaf value.
2763 dbAdjTree(tp, leafno, newval);
2770 * FUNCTION: update a leaf of a dmtree with a new value, adjusting
2771 * the dmtree, as required, to reflect the new leaf value.
2772 * the combination of any buddies must already be done before
2776 * tp - pointer to the tree to be adjusted.
2777 * leafno - the number of the leaf to be updated.
2778 * newval - the new value for the leaf.
2780 * RETURN VALUES: none
2782 static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2787 /* pick up the index of the leaf for this leafno.
2789 lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2791 /* is the current value the same as the old value ? if so,
2792 * there is nothing to do.
2794 if (tp->dmt_stree[lp] == newval)
2797 /* set the new value.
2799 tp->dmt_stree[lp] = newval;
2801 /* bubble the new value up the tree as required.
2803 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2804 /* get the index of the first leaf of the 4 leaf
2805 * group containing the specified leaf (leafno).
2807 lp = ((lp - 1) & ~0x03) + 1;
2809 /* get the index of the parent of this 4 leaf group.
2813 /* determine the maximum of the 4 leaves.
2815 max = TREEMAX(&tp->dmt_stree[lp]);
2817 /* if the maximum of the 4 is the same as the
2818 * parent's value, we're done.
2820 if (tp->dmt_stree[pp] == max)
2823 /* parent gets new value.
2825 tp->dmt_stree[pp] = max;
2827 /* parent becomes leaf for next go-round.
2835 * NAME: dbFindLeaf()
2837 * FUNCTION: search a dmtree_t for sufficient free blocks, returning
2838 * the index of a leaf describing the free blocks if
2839 * sufficient free blocks are found.
2841 * the search starts at the top of the dmtree_t tree and
2842 * proceeds down the tree to the leftmost leaf with sufficient
2846 * tp - pointer to the tree to be searched.
2847 * l2nb - log2 number of free blocks to search for.
2848 * leafidx - return pointer to be set to the index of the leaf
2849 * describing at least l2nb free blocks if sufficient
2850 * free blocks are found.
2854 * -ENOSPC - insufficient free blocks.
2856 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2858 int ti, n = 0, k, x = 0;
2860 /* first check the root of the tree to see if there is
2861 * sufficient free space.
2863 if (l2nb > tp->dmt_stree[ROOT])
2866 /* sufficient free space available. now search down the tree
2867 * starting at the next level for the leftmost leaf that
2868 * describes sufficient free space.
2870 for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2871 k > 0; k--, ti = ((ti + n) << 2) + 1) {
2872 /* search the four nodes at this level, starting from
2875 for (x = ti, n = 0; n < 4; n++) {
2876 /* sufficient free space found. move to the next
2877 * level (or quit if this is the last level).
2879 if (l2nb <= tp->dmt_stree[x + n])
2883 /* better have found something since the higher
2884 * levels of the tree said it was here.
2889 /* set the return to the leftmost leaf describing sufficient
2892 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2899 * NAME: dbFindBits()
2901 * FUNCTION: find a specified number of binary buddy free bits within a
2902 * dmap bitmap word value.
2904 * this routine searches the bitmap value for (1 << l2nb) free
2905 * bits at (1 << l2nb) alignments within the value.
2908 * word - dmap bitmap word value.
2909 * l2nb - number of free bits specified as a log2 number.
2912 * starting bit number of free bits.
2914 static int dbFindBits(u32 word, int l2nb)
2919 /* get the number of bits.
2922 assert(nb <= DBWORD);
2924 /* complement the word so we can use a mask (i.e. 0s represent
2925 * free bits) and compute the mask.
2928 mask = ONES << (DBWORD - nb);
2930 /* scan the word for nb free bits at nb alignments.
2932 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2933 if ((mask & word) == mask)
2939 /* return the bit number.
2946 * NAME: dbMaxBud(u8 *cp)
2948 * FUNCTION: determine the largest binary buddy string of free
2949 * bits within 32-bits of the map.
2952 * cp - pointer to the 32-bit value.
2955 * largest binary buddy of free bits within a dmap word.
2957 static int dbMaxBud(u8 * cp)
2959 signed char tmp1, tmp2;
2961 /* check if the wmap word is all free. if so, the
2962 * free buddy size is BUDMIN.
2964 if (*((uint *) cp) == 0)
2967 /* check if the wmap word is half free. if so, the
2968 * free buddy size is BUDMIN-1.
2970 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
2971 return (BUDMIN - 1);
2973 /* not all free or half free. determine the free buddy
2974 * size thru table lookup using quarters of the wmap word.
2976 tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
2977 tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
2978 return (max(tmp1, tmp2));
2983 * NAME: cnttz(uint word)
2985 * FUNCTION: determine the number of trailing zeros within a 32-bit
2989 * value - 32-bit value to be examined.
2992 * count of trailing zeros
2994 static int cnttz(u32 word)
2998 for (n = 0; n < 32; n++, word >>= 1) {
3008 * NAME: cntlz(u32 value)
3010 * FUNCTION: determine the number of leading zeros within a 32-bit
3014 * value - 32-bit value to be examined.
3017 * count of leading zeros
3019 static int cntlz(u32 value)
3023 for (n = 0; n < 32; n++, value <<= 1) {
3024 if (value & HIGHORDER)
3032 * NAME: blkstol2(s64 nb)
3034 * FUNCTION: convert a block count to its log2 value. if the block
3035 * count is not a l2 multiple, it is rounded up to the next
3036 * larger l2 multiple.
3039 * nb - number of blocks
3042 * log2 number of blocks
3044 int blkstol2(s64 nb)
3047 s64 mask; /* meant to be signed */
3049 mask = (s64) 1 << (64 - 1);
3051 /* count the leading bits.
3053 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3054 /* leading bit found.
3057 /* determine the l2 value.
3059 l2nb = (64 - 1) - l2nb;
3061 /* check if we need to round up.
3070 return 0; /* fix compiler warning */
3075 * NAME: dbAllocBottomUp()
3077 * FUNCTION: alloc the specified block range from the working block
3080 * the blocks will be alloc from the working map one dmap
3084 * ip - pointer to in-core inode;
3085 * blkno - starting block number to be freed.
3086 * nblocks - number of blocks to be freed.
3092 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3094 struct metapage *mp;
3098 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3099 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3103 /* block to be allocated better be within the mapsize. */
3104 ASSERT(nblocks <= bmp->db_mapsize - blkno);
3107 * allocate the blocks a dmap at a time.
3110 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3111 /* release previous dmap if any */
3116 /* get the buffer for the current dmap. */
3117 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3118 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3120 IREAD_UNLOCK(ipbmap);
3123 dp = (struct dmap *) mp->data;
3125 /* determine the number of blocks to be allocated from
3128 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3130 /* allocate the blocks. */
3131 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3132 release_metapage(mp);
3133 IREAD_UNLOCK(ipbmap);
3138 /* write the last buffer. */
3141 IREAD_UNLOCK(ipbmap);
3147 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3151 int dbitno, word, rembits, nb, nwords, wbitno, agno;
3153 struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3155 /* save the current value of the root (i.e. maximum free string)
3158 oldroot = tp->stree[ROOT];
3160 /* pick up a pointer to the leaves of the dmap tree */
3161 leaf = tp->stree + LEAFIND;
3163 /* determine the bit number and word within the dmap of the
3166 dbitno = blkno & (BPERDMAP - 1);
3167 word = dbitno >> L2DBWORD;
3169 /* block range better be within the dmap */
3170 assert(dbitno + nblocks <= BPERDMAP);
3172 /* allocate the bits of the dmap's words corresponding to the block
3173 * range. not all bits of the first and last words may be contained
3174 * within the block range. if this is the case, we'll work against
3175 * those words (i.e. partial first and/or last) on an individual basis
3176 * (a single pass), allocating the bits of interest by hand and
3177 * updating the leaf corresponding to the dmap word. a single pass
3178 * will be used for all dmap words fully contained within the
3179 * specified range. within this pass, the bits of all fully contained
3180 * dmap words will be marked as free in a single shot and the leaves
3181 * will be updated. a single leaf may describe the free space of
3182 * multiple dmap words, so we may update only a subset of the actual
3183 * leaves corresponding to the dmap words of the block range.
3185 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3186 /* determine the bit number within the word and
3187 * the number of bits within the word.
3189 wbitno = dbitno & (DBWORD - 1);
3190 nb = min(rembits, DBWORD - wbitno);
3192 /* check if only part of a word is to be allocated.
3195 /* allocate (set to 1) the appropriate bits within
3198 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3203 /* one or more dmap words are fully contained
3204 * within the block range. determine how many
3205 * words and allocate (set to 1) the bits of these
3208 nwords = rembits >> L2DBWORD;
3209 memset(&dp->wmap[word], (int) ONES, nwords * 4);
3211 /* determine how many bits */
3212 nb = nwords << L2DBWORD;
3217 /* update the free count for this dmap */
3218 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
3220 /* reconstruct summary tree */
3225 /* if this allocation group is completely free,
3226 * update the highest active allocation group number
3227 * if this allocation group is the new max.
3229 agno = blkno >> bmp->db_agl2size;
3230 if (agno > bmp->db_maxag)
3231 bmp->db_maxag = agno;
3233 /* update the free count for the allocation group and map */
3234 bmp->db_agfree[agno] -= nblocks;
3235 bmp->db_nfree -= nblocks;
3239 /* if the root has not changed, done. */
3240 if (tp->stree[ROOT] == oldroot)
3243 /* root changed. bubble the change up to the dmap control pages.
3244 * if the adjustment of the upper level control pages fails,
3245 * backout the bit allocation (thus making everything consistent).
3247 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3248 dbFreeBits(bmp, dp, blkno, nblocks);
3255 * NAME: dbExtendFS()
3257 * FUNCTION: extend bmap from blkno for nblocks;
3258 * dbExtendFS() updates bmap ready for dbAllocBottomUp();
3262 * L1---------------------------------L1
3264 * L0---------L0---------L0 L0---------L0---------L0
3266 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
3267 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3269 * <---old---><----------------------------extend----------------------->
3271 int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3273 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3274 int nbperpage = sbi->nbperpage;
3275 int i, i0 = TRUE, j, j0 = TRUE, k, n;
3278 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3279 struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3281 s8 *l0leaf, *l1leaf, *l2leaf;
3282 struct bmap *bmp = sbi->bmap;
3283 int agno, l2agsize, oldl2agsize;
3286 newsize = blkno + nblocks;
3288 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3289 (long long) blkno, (long long) nblocks, (long long) newsize);
3292 * initialize bmap control page.
3294 * all the data in bmap control page should exclude
3295 * the mkfs hidden dmap page.
3298 /* update mapsize */
3299 bmp->db_mapsize = newsize;
3300 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3302 /* compute new AG size */
3303 l2agsize = dbGetL2AGSize(newsize);
3304 oldl2agsize = bmp->db_agl2size;
3306 bmp->db_agl2size = l2agsize;
3307 bmp->db_agsize = 1 << l2agsize;
3309 /* compute new number of AG */
3310 agno = bmp->db_numag;
3311 bmp->db_numag = newsize >> l2agsize;
3312 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3315 * reconfigure db_agfree[]
3316 * from old AG configuration to new AG configuration;
3318 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3319 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3320 * note: new AG size = old AG size * (2**x).
3322 if (l2agsize == oldl2agsize)
3324 k = 1 << (l2agsize - oldl2agsize);
3325 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
3326 for (i = 0, n = 0; i < agno; n++) {
3327 bmp->db_agfree[n] = 0; /* init collection point */
3329 /* coalesce cotiguous k AGs; */
3330 for (j = 0; j < k && i < agno; j++, i++) {
3331 /* merge AGi to AGn */
3332 bmp->db_agfree[n] += bmp->db_agfree[i];
3335 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
3337 for (; n < MAXAG; n++)
3338 bmp->db_agfree[n] = 0;
3341 * update highest active ag number
3344 bmp->db_maxag = bmp->db_maxag / k;
3349 * update bit maps and corresponding level control pages;
3350 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3354 p = BMAPBLKNO + nbperpage; /* L2 page */
3355 l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3357 jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
3360 l2dcp = (struct dmapctl *) l2mp->data;
3362 /* compute start L1 */
3363 k = blkno >> L2MAXL1SIZE;
3364 l2leaf = l2dcp->stree + CTLLEAFIND + k;
3365 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
3368 * extend each L1 in L2
3370 for (; k < LPERCTL; k++, p += nbperpage) {
3373 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3374 l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3377 l1dcp = (struct dmapctl *) l1mp->data;
3379 /* compute start L0 */
3380 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3381 l1leaf = l1dcp->stree + CTLLEAFIND + j;
3382 p = BLKTOL0(blkno, sbi->l2nbperpage);
3385 /* assign/init L1 page */
3386 l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3390 l1dcp = (struct dmapctl *) l1mp->data;
3392 /* compute start L0 */
3394 l1leaf = l1dcp->stree + CTLLEAFIND;
3395 p += nbperpage; /* 1st L0 of L1.k */
3399 * extend each L0 in L1
3401 for (; j < LPERCTL; j++) {
3404 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3406 l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3409 l0dcp = (struct dmapctl *) l0mp->data;
3411 /* compute start dmap */
3412 i = (blkno & (MAXL0SIZE - 1)) >>
3414 l0leaf = l0dcp->stree + CTLLEAFIND + i;
3415 p = BLKTODMAP(blkno,
3419 /* assign/init L0 page */
3420 l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3424 l0dcp = (struct dmapctl *) l0mp->data;
3426 /* compute start dmap */
3428 l0leaf = l0dcp->stree + CTLLEAFIND;
3429 p += nbperpage; /* 1st dmap of L0.j */
3433 * extend each dmap in L0
3435 for (; i < LPERCTL; i++) {
3437 * reconstruct the dmap page, and
3438 * initialize corresponding parent L0 leaf
3440 if ((n = blkno & (BPERDMAP - 1))) {
3441 /* read in dmap page: */
3442 mp = read_metapage(ipbmap, p,
3446 n = min(nblocks, (s64)BPERDMAP - n);
3448 /* assign/init dmap page */
3449 mp = read_metapage(ipbmap, p,
3454 n = min(nblocks, (s64)BPERDMAP);
3457 dp = (struct dmap *) mp->data;
3458 *l0leaf = dbInitDmap(dp, blkno, n);
3461 agno = le64_to_cpu(dp->start) >> l2agsize;
3462 bmp->db_agfree[agno] += n;
3473 } /* for each dmap in a L0 */
3476 * build current L0 page from its leaves, and
3477 * initialize corresponding parent L1 leaf
3479 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3480 write_metapage(l0mp);
3484 l1leaf++; /* continue for next L0 */
3486 /* more than 1 L0 ? */
3488 break; /* build L1 page */
3490 /* summarize in global bmap page */
3491 bmp->db_maxfreebud = *l1leaf;
3492 release_metapage(l1mp);
3493 release_metapage(l2mp);
3497 } /* for each L0 in a L1 */
3500 * build current L1 page from its leaves, and
3501 * initialize corresponding parent L2 leaf
3503 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3504 write_metapage(l1mp);
3508 l2leaf++; /* continue for next L1 */
3510 /* more than 1 L1 ? */
3512 break; /* build L2 page */
3514 /* summarize in global bmap page */
3515 bmp->db_maxfreebud = *l2leaf;
3516 release_metapage(l2mp);
3520 } /* for each L1 in a L2 */
3522 jfs_error(ipbmap->i_sb,
3523 "dbExtendFS: function has not returned as expected");
3526 release_metapage(l0mp);
3528 release_metapage(l1mp);
3529 release_metapage(l2mp);
3533 * finalize bmap control page
3544 void dbFinalizeBmap(struct inode *ipbmap)
3546 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3547 int actags, inactags, l2nl;
3548 s64 ag_rem, actfree, inactfree, avgfree;
3552 * finalize bmap control page
3556 * compute db_agpref: preferred ag to allocate from
3557 * (the leftmost ag with average free space in it);
3560 /* get the number of active ags and inacitve ags */
3561 actags = bmp->db_maxag + 1;
3562 inactags = bmp->db_numag - actags;
3563 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
3565 /* determine how many blocks are in the inactive allocation
3566 * groups. in doing this, we must account for the fact that
3567 * the rightmost group might be a partial group (i.e. file
3568 * system size is not a multiple of the group size).
3570 inactfree = (inactags && ag_rem) ?
3571 ((inactags - 1) << bmp->db_agl2size) + ag_rem
3572 : inactags << bmp->db_agl2size;
3574 /* determine how many free blocks are in the active
3575 * allocation groups plus the average number of free blocks
3576 * within the active ags.
3578 actfree = bmp->db_nfree - inactfree;
3579 avgfree = (u32) actfree / (u32) actags;
3581 /* if the preferred allocation group has not average free space.
3582 * re-establish the preferred group as the leftmost
3583 * group with average free space.
3585 if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3586 for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3588 if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3591 if (bmp->db_agpref >= bmp->db_numag) {
3592 jfs_error(ipbmap->i_sb,
3593 "cannot find ag with average freespace");
3598 * compute db_aglevel, db_agheigth, db_width, db_agstart:
3599 * an ag is covered in aglevel dmapctl summary tree,
3600 * at agheight level height (from leaf) with agwidth number of nodes
3601 * each, which starts at agstart index node of the smmary tree node
3604 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3606 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3607 bmp->db_agheigth = l2nl >> 1;
3608 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheigth << 1));
3609 for (i = 5 - bmp->db_agheigth, bmp->db_agstart = 0, n = 1; i > 0;
3611 bmp->db_agstart += n;
3619 * NAME: dbInitDmap()/ujfs_idmap_page()
3621 * FUNCTION: initialize working/persistent bitmap of the dmap page
3622 * for the specified number of blocks:
3624 * at entry, the bitmaps had been initialized as free (ZEROS);
3625 * The number of blocks will only account for the actually
3626 * existing blocks. Blocks which don't actually exist in
3627 * the aggregate will be marked as allocated (ONES);
3630 * dp - pointer to page of map
3631 * nblocks - number of blocks this page
3635 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3637 int blkno, w, b, r, nw, nb, i;
3639 /* starting block number within the dmap */
3640 blkno = Blkno & (BPERDMAP - 1);
3643 dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3644 dp->start = cpu_to_le64(Blkno);
3646 if (nblocks == BPERDMAP) {
3647 memset(&dp->wmap[0], 0, LPERDMAP * 4);
3648 memset(&dp->pmap[0], 0, LPERDMAP * 4);
3653 cpu_to_le32(le32_to_cpu(dp->nblocks) + nblocks);
3654 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
3657 /* word number containing start block number */
3658 w = blkno >> L2DBWORD;
3661 * free the bits corresponding to the block range (ZEROS):
3662 * note: not all bits of the first and last words may be contained
3663 * within the block range.
3665 for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3666 /* number of bits preceding range to be freed in the word */
3667 b = blkno & (DBWORD - 1);
3668 /* number of bits to free in the word */
3669 nb = min(r, DBWORD - b);
3671 /* is partial word to be freed ? */
3673 /* free (set to 0) from the bitmap word */
3674 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3676 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3679 /* skip the word freed */
3682 /* free (set to 0) contiguous bitmap words */
3684 memset(&dp->wmap[w], 0, nw * 4);
3685 memset(&dp->pmap[w], 0, nw * 4);
3687 /* skip the words freed */
3688 nb = nw << L2DBWORD;
3694 * mark bits following the range to be freed (non-existing
3695 * blocks) as allocated (ONES)
3698 if (blkno == BPERDMAP)
3701 /* the first word beyond the end of existing blocks */
3702 w = blkno >> L2DBWORD;
3704 /* does nblocks fall on a 32-bit boundary ? */
3705 b = blkno & (DBWORD - 1);
3707 /* mark a partial word allocated */
3708 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3712 /* set the rest of the words in the page to allocated (ONES) */
3713 for (i = w; i < LPERDMAP; i++)
3714 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3720 return (dbInitDmapTree(dp));
3725 * NAME: dbInitDmapTree()/ujfs_complete_dmap()
3727 * FUNCTION: initialize summary tree of the specified dmap:
3729 * at entry, bitmap of the dmap has been initialized;
3732 * dp - dmap to complete
3733 * blkno - starting block number for this dmap
3734 * treemax - will be filled in with max free for this dmap
3736 * RETURNS: max free string at the root of the tree
3738 static int dbInitDmapTree(struct dmap * dp)
3740 struct dmaptree *tp;
3744 /* init fixed info of tree */
3746 tp->nleafs = cpu_to_le32(LPERDMAP);
3747 tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3748 tp->leafidx = cpu_to_le32(LEAFIND);
3749 tp->height = cpu_to_le32(4);
3750 tp->budmin = BUDMIN;
3752 /* init each leaf from corresponding wmap word:
3753 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3754 * bitmap word are allocated.
3756 cp = tp->stree + le32_to_cpu(tp->leafidx);
3757 for (i = 0; i < LPERDMAP; i++)
3758 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3760 /* build the dmap's binary buddy summary tree */
3761 return (dbInitTree(tp));
3766 * NAME: dbInitTree()/ujfs_adjtree()
3768 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
3770 * at entry, the leaves of the tree has been initialized
3771 * from corresponding bitmap word or root of summary tree
3772 * of the child control page;
3773 * configure binary buddy system at the leaf level, then
3774 * bubble up the values of the leaf nodes up the tree.
3777 * cp - Pointer to the root of the tree
3778 * l2leaves- Number of leaf nodes as a power of 2
3779 * l2min - Number of blocks that can be covered by a leaf
3782 * RETURNS: max free string at the root of the tree
3784 static int dbInitTree(struct dmaptree * dtp)
3786 int l2max, l2free, bsize, nextb, i;
3787 int child, parent, nparent;
3792 /* Determine the maximum free string possible for the leaves */
3793 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3796 * configure the leaf levevl into binary buddy system
3798 * Try to combine buddies starting with a buddy size of 1
3799 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3800 * can be combined if both buddies have a maximum free of l2min;
3801 * the combination will result in the left-most buddy leaf having
3802 * a maximum free of l2min+1.
3803 * After processing all buddies for a given size, process buddies
3804 * at the next higher buddy size (i.e. current size * 2) and
3805 * the next maximum free (current free + 1).
3806 * This continues until the maximum possible buddy combination
3807 * yields maximum free.
3809 for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3810 l2free++, bsize = nextb) {
3811 /* get next buddy size == current buddy pair size */
3814 /* scan each adjacent buddy pair at current buddy size */
3815 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3816 i < le32_to_cpu(dtp->nleafs);
3817 i += nextb, cp += nextb) {
3818 /* coalesce if both adjacent buddies are max free */
3819 if (*cp == l2free && *(cp + bsize) == l2free) {
3820 *cp = l2free + 1; /* left take right */
3821 *(cp + bsize) = -1; /* right give left */
3827 * bubble summary information of leaves up the tree.
3829 * Starting at the leaf node level, the four nodes described by
3830 * the higher level parent node are compared for a maximum free and
3831 * this maximum becomes the value of the parent node.
3832 * when all lower level nodes are processed in this fashion then
3833 * move up to the next level (parent becomes a lower level node) and
3834 * continue the process for that level.
3836 for (child = le32_to_cpu(dtp->leafidx),
3837 nparent = le32_to_cpu(dtp->nleafs) >> 2;
3838 nparent > 0; nparent >>= 2, child = parent) {
3839 /* get index of 1st node of parent level */
3840 parent = (child - 1) >> 2;
3842 /* set the value of the parent node as the maximum
3843 * of the four nodes of the current level.
3845 for (i = 0, cp = tp + child, cp1 = tp + parent;
3846 i < nparent; i++, cp += 4, cp1++)
3857 * function: initialize dmapctl page
3859 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3860 { /* start leaf index not covered by range */
3863 dcp->nleafs = cpu_to_le32(LPERCTL);
3864 dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3865 dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3866 dcp->height = cpu_to_le32(5);
3867 dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3870 * initialize the leaves of current level that were not covered
3871 * by the specified input block range (i.e. the leaves have no
3872 * low level dmapctl or dmap).
3874 cp = &dcp->stree[CTLLEAFIND + i];
3875 for (; i < LPERCTL; i++)
3878 /* build the dmap's binary buddy summary tree */
3879 return (dbInitTree((struct dmaptree *) dcp));
3884 * NAME: dbGetL2AGSize()/ujfs_getagl2size()
3886 * FUNCTION: Determine log2(allocation group size) from aggregate size
3889 * nblocks - Number of blocks in aggregate
3891 * RETURNS: log2(allocation group size) in aggregate blocks
3893 static int dbGetL2AGSize(s64 nblocks)
3899 if (nblocks < BPERDMAP * MAXAG)
3900 return (L2BPERDMAP);
3902 /* round up aggregate size to power of 2 */
3903 m = ((u64) 1 << (64 - 1));
3904 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3909 sz = (s64) 1 << l2sz;
3913 /* agsize = roundupSize/max_number_of_ag */
3914 return (l2sz - L2MAXAG);
3919 * NAME: dbMapFileSizeToMapSize()
3921 * FUNCTION: compute number of blocks the block allocation map file
3922 * can cover from the map file size;
3924 * RETURNS: Number of blocks which can be covered by this block map file;
3928 * maximum number of map pages at each level including control pages
3930 #define MAXL0PAGES (1 + LPERCTL)
3931 #define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
3932 #define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
3935 * convert number of map pages to the zero origin top dmapctl level
3937 #define BMAPPGTOLEV(npages) \
3938 (((npages) <= 3 + MAXL0PAGES) ? 0 \
3939 : ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
3941 s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3943 struct super_block *sb = ipbmap->i_sb;
3947 int complete, factor;
3949 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
3950 npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
3951 level = BMAPPGTOLEV(npages);
3953 /* At each level, accumulate the number of dmap pages covered by
3954 * the number of full child levels below it;
3955 * repeat for the last incomplete child level.
3958 npages--; /* skip the first global control page */
3959 /* skip higher level control pages above top level covered by map */
3960 npages -= (2 - level);
3961 npages--; /* skip top level's control page */
3962 for (i = level; i >= 0; i--) {
3964 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
3965 complete = (u32) npages / factor;
3966 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL
3967 : ((i == 1) ? LPERCTL : 1));
3969 /* pages in last/incomplete child */
3970 npages = (u32) npages % factor;
3971 /* skip incomplete child's level control page */
3975 /* convert the number of dmaps into the number of blocks
3976 * which can be covered by the dmaps;
3978 nblocks = ndmaps << L2BPERDMAP;