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1/*
2 * Copyright (C) International Business Machines Corp., 2000-2004
3 * Portions Copyright (C) Tino Reichardt, 2012
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/fs.h>
21#include <linux/slab.h>
22#include "jfs_incore.h"
23#include "jfs_superblock.h"
24#include "jfs_dmap.h"
25#include "jfs_imap.h"
26#include "jfs_lock.h"
27#include "jfs_metapage.h"
28#include "jfs_debug.h"
29#include "jfs_discard.h"
30
31/*
32 * SERIALIZATION of the Block Allocation Map.
33 *
34 * the working state of the block allocation map is accessed in
35 * two directions:
36 *
37 * 1) allocation and free requests that start at the dmap
38 * level and move up through the dmap control pages (i.e.
39 * the vast majority of requests).
40 *
41 * 2) allocation requests that start at dmap control page
42 * level and work down towards the dmaps.
43 *
44 * the serialization scheme used here is as follows.
45 *
46 * requests which start at the bottom are serialized against each
47 * other through buffers and each requests holds onto its buffers
48 * as it works it way up from a single dmap to the required level
49 * of dmap control page.
50 * requests that start at the top are serialized against each other
51 * and request that start from the bottom by the multiple read/single
52 * write inode lock of the bmap inode. requests starting at the top
53 * take this lock in write mode while request starting at the bottom
54 * take the lock in read mode. a single top-down request may proceed
55 * exclusively while multiple bottoms-up requests may proceed
56 * simultaneously (under the protection of busy buffers).
57 *
58 * in addition to information found in dmaps and dmap control pages,
59 * the working state of the block allocation map also includes read/
60 * write information maintained in the bmap descriptor (i.e. total
61 * free block count, allocation group level free block counts).
62 * a single exclusive lock (BMAP_LOCK) is used to guard this information
63 * in the face of multiple-bottoms up requests.
64 * (lock ordering: IREAD_LOCK, BMAP_LOCK);
65 *
66 * accesses to the persistent state of the block allocation map (limited
67 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
68 */
69
70#define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
71#define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
72#define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
73
74/*
75 * forward references
76 */
77static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
78 int nblocks);
79static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
80static int dbBackSplit(dmtree_t * tp, int leafno);
81static int dbJoin(dmtree_t * tp, int leafno, int newval);
82static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
83static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
84 int level);
85static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
86static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
87 int nblocks);
88static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
89 int nblocks,
90 int l2nb, s64 * results);
91static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
92 int nblocks);
93static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
94 int l2nb,
95 s64 * results);
96static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
97 s64 * results);
98static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
99 s64 * results);
100static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
101static int dbFindBits(u32 word, int l2nb);
102static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
103static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
104static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
105 int nblocks);
106static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
107 int nblocks);
108static int dbMaxBud(u8 * cp);
109static int blkstol2(s64 nb);
110
111static int cntlz(u32 value);
112static int cnttz(u32 word);
113
114static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
115 int nblocks);
116static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
117static int dbInitDmapTree(struct dmap * dp);
118static int dbInitTree(struct dmaptree * dtp);
119static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
120static int dbGetL2AGSize(s64 nblocks);
121
122/*
123 * buddy table
124 *
125 * table used for determining buddy sizes within characters of
126 * dmap bitmap words. the characters themselves serve as indexes
127 * into the table, with the table elements yielding the maximum
128 * binary buddy of free bits within the character.
129 */
130static const s8 budtab[256] = {
131 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
135 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
136 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
137 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
138 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
139 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
140 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
141 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
142 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
143 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
144 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
145 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
146 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
147};
148
149/*
150 * NAME: dbMount()
151 *
152 * FUNCTION: initializate the block allocation map.
153 *
154 * memory is allocated for the in-core bmap descriptor and
155 * the in-core descriptor is initialized from disk.
156 *
157 * PARAMETERS:
158 * ipbmap - pointer to in-core inode for the block map.
159 *
160 * RETURN VALUES:
161 * 0 - success
162 * -ENOMEM - insufficient memory
163 * -EIO - i/o error
164 */
165int dbMount(struct inode *ipbmap)
166{
167 struct bmap *bmp;
168 struct dbmap_disk *dbmp_le;
169 struct metapage *mp;
170 int i;
171
172 /*
173 * allocate/initialize the in-memory bmap descriptor
174 */
175 /* allocate memory for the in-memory bmap descriptor */
176 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
177 if (bmp == NULL)
178 return -ENOMEM;
179
180 /* read the on-disk bmap descriptor. */
181 mp = read_metapage(ipbmap,
182 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
183 PSIZE, 0);
184 if (mp == NULL) {
185 kfree(bmp);
186 return -EIO;
187 }
188
189 /* copy the on-disk bmap descriptor to its in-memory version. */
190 dbmp_le = (struct dbmap_disk *) mp->data;
191 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
192 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
193 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
194 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
195 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
196 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
197 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
198 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
199 bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
200 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
201 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
202 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
203 for (i = 0; i < MAXAG; i++)
204 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
205 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
206 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
207
208 /* release the buffer. */
209 release_metapage(mp);
210
211 /* bind the bmap inode and the bmap descriptor to each other. */
212 bmp->db_ipbmap = ipbmap;
213 JFS_SBI(ipbmap->i_sb)->bmap = bmp;
214
215 memset(bmp->db_active, 0, sizeof(bmp->db_active));
216
217 /*
218 * allocate/initialize the bmap lock
219 */
220 BMAP_LOCK_INIT(bmp);
221
222 return (0);
223}
224
225
226/*
227 * NAME: dbUnmount()
228 *
229 * FUNCTION: terminate the block allocation map in preparation for
230 * file system unmount.
231 *
232 * the in-core bmap descriptor is written to disk and
233 * the memory for this descriptor is freed.
234 *
235 * PARAMETERS:
236 * ipbmap - pointer to in-core inode for the block map.
237 *
238 * RETURN VALUES:
239 * 0 - success
240 * -EIO - i/o error
241 */
242int dbUnmount(struct inode *ipbmap, int mounterror)
243{
244 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
245
246 if (!(mounterror || isReadOnly(ipbmap)))
247 dbSync(ipbmap);
248
249 /*
250 * Invalidate the page cache buffers
251 */
252 truncate_inode_pages(ipbmap->i_mapping, 0);
253
254 /* free the memory for the in-memory bmap. */
255 kfree(bmp);
256
257 return (0);
258}
259
260/*
261 * dbSync()
262 */
263int dbSync(struct inode *ipbmap)
264{
265 struct dbmap_disk *dbmp_le;
266 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
267 struct metapage *mp;
268 int i;
269
270 /*
271 * write bmap global control page
272 */
273 /* get the buffer for the on-disk bmap descriptor. */
274 mp = read_metapage(ipbmap,
275 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
276 PSIZE, 0);
277 if (mp == NULL) {
278 jfs_err("dbSync: read_metapage failed!");
279 return -EIO;
280 }
281 /* copy the in-memory version of the bmap to the on-disk version */
282 dbmp_le = (struct dbmap_disk *) mp->data;
283 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
284 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
285 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
286 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
287 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
288 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
289 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
290 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
291 dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
292 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
293 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
294 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
295 for (i = 0; i < MAXAG; i++)
296 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
297 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
298 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
299
300 /* write the buffer */
301 write_metapage(mp);
302
303 /*
304 * write out dirty pages of bmap
305 */
306 filemap_write_and_wait(ipbmap->i_mapping);
307
308 diWriteSpecial(ipbmap, 0);
309
310 return (0);
311}
312
313/*
314 * NAME: dbFree()
315 *
316 * FUNCTION: free the specified block range from the working block
317 * allocation map.
318 *
319 * the blocks will be free from the working map one dmap
320 * at a time.
321 *
322 * PARAMETERS:
323 * ip - pointer to in-core inode;
324 * blkno - starting block number to be freed.
325 * nblocks - number of blocks to be freed.
326 *
327 * RETURN VALUES:
328 * 0 - success
329 * -EIO - i/o error
330 */
331int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
332{
333 struct metapage *mp;
334 struct dmap *dp;
335 int nb, rc;
336 s64 lblkno, rem;
337 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
338 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
339 struct super_block *sb = ipbmap->i_sb;
340
341 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
342
343 /* block to be freed better be within the mapsize. */
344 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
345 IREAD_UNLOCK(ipbmap);
346 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
347 (unsigned long long) blkno,
348 (unsigned long long) nblocks);
349 jfs_error(ip->i_sb, "block to be freed is outside the map\n");
350 return -EIO;
351 }
352
353 /**
354 * TRIM the blocks, when mounted with discard option
355 */
356 if (JFS_SBI(sb)->flag & JFS_DISCARD)
357 if (JFS_SBI(sb)->minblks_trim <= nblocks)
358 jfs_issue_discard(ipbmap, blkno, nblocks);
359
360 /*
361 * free the blocks a dmap at a time.
362 */
363 mp = NULL;
364 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
365 /* release previous dmap if any */
366 if (mp) {
367 write_metapage(mp);
368 }
369
370 /* get the buffer for the current dmap. */
371 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
372 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
373 if (mp == NULL) {
374 IREAD_UNLOCK(ipbmap);
375 return -EIO;
376 }
377 dp = (struct dmap *) mp->data;
378
379 /* determine the number of blocks to be freed from
380 * this dmap.
381 */
382 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
383
384 /* free the blocks. */
385 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
386 jfs_error(ip->i_sb, "error in block map\n");
387 release_metapage(mp);
388 IREAD_UNLOCK(ipbmap);
389 return (rc);
390 }
391 }
392
393 /* write the last buffer. */
394 write_metapage(mp);
395
396 IREAD_UNLOCK(ipbmap);
397
398 return (0);
399}
400
401
402/*
403 * NAME: dbUpdatePMap()
404 *
405 * FUNCTION: update the allocation state (free or allocate) of the
406 * specified block range in the persistent block allocation map.
407 *
408 * the blocks will be updated in the persistent map one
409 * dmap at a time.
410 *
411 * PARAMETERS:
412 * ipbmap - pointer to in-core inode for the block map.
413 * free - 'true' if block range is to be freed from the persistent
414 * map; 'false' if it is to be allocated.
415 * blkno - starting block number of the range.
416 * nblocks - number of contiguous blocks in the range.
417 * tblk - transaction block;
418 *
419 * RETURN VALUES:
420 * 0 - success
421 * -EIO - i/o error
422 */
423int
424dbUpdatePMap(struct inode *ipbmap,
425 int free, s64 blkno, s64 nblocks, struct tblock * tblk)
426{
427 int nblks, dbitno, wbitno, rbits;
428 int word, nbits, nwords;
429 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
430 s64 lblkno, rem, lastlblkno;
431 u32 mask;
432 struct dmap *dp;
433 struct metapage *mp;
434 struct jfs_log *log;
435 int lsn, difft, diffp;
436 unsigned long flags;
437
438 /* the blocks better be within the mapsize. */
439 if (blkno + nblocks > bmp->db_mapsize) {
440 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
441 (unsigned long long) blkno,
442 (unsigned long long) nblocks);
443 jfs_error(ipbmap->i_sb, "blocks are outside the map\n");
444 return -EIO;
445 }
446
447 /* compute delta of transaction lsn from log syncpt */
448 lsn = tblk->lsn;
449 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
450 logdiff(difft, lsn, log);
451
452 /*
453 * update the block state a dmap at a time.
454 */
455 mp = NULL;
456 lastlblkno = 0;
457 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
458 /* get the buffer for the current dmap. */
459 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
460 if (lblkno != lastlblkno) {
461 if (mp) {
462 write_metapage(mp);
463 }
464
465 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
466 0);
467 if (mp == NULL)
468 return -EIO;
469 metapage_wait_for_io(mp);
470 }
471 dp = (struct dmap *) mp->data;
472
473 /* determine the bit number and word within the dmap of
474 * the starting block. also determine how many blocks
475 * are to be updated within this dmap.
476 */
477 dbitno = blkno & (BPERDMAP - 1);
478 word = dbitno >> L2DBWORD;
479 nblks = min(rem, (s64)BPERDMAP - dbitno);
480
481 /* update the bits of the dmap words. the first and last
482 * words may only have a subset of their bits updated. if
483 * this is the case, we'll work against that word (i.e.
484 * partial first and/or last) only in a single pass. a
485 * single pass will also be used to update all words that
486 * are to have all their bits updated.
487 */
488 for (rbits = nblks; rbits > 0;
489 rbits -= nbits, dbitno += nbits) {
490 /* determine the bit number within the word and
491 * the number of bits within the word.
492 */
493 wbitno = dbitno & (DBWORD - 1);
494 nbits = min(rbits, DBWORD - wbitno);
495
496 /* check if only part of the word is to be updated. */
497 if (nbits < DBWORD) {
498 /* update (free or allocate) the bits
499 * in this word.
500 */
501 mask =
502 (ONES << (DBWORD - nbits) >> wbitno);
503 if (free)
504 dp->pmap[word] &=
505 cpu_to_le32(~mask);
506 else
507 dp->pmap[word] |=
508 cpu_to_le32(mask);
509
510 word += 1;
511 } else {
512 /* one or more words are to have all
513 * their bits updated. determine how
514 * many words and how many bits.
515 */
516 nwords = rbits >> L2DBWORD;
517 nbits = nwords << L2DBWORD;
518
519 /* update (free or allocate) the bits
520 * in these words.
521 */
522 if (free)
523 memset(&dp->pmap[word], 0,
524 nwords * 4);
525 else
526 memset(&dp->pmap[word], (int) ONES,
527 nwords * 4);
528
529 word += nwords;
530 }
531 }
532
533 /*
534 * update dmap lsn
535 */
536 if (lblkno == lastlblkno)
537 continue;
538
539 lastlblkno = lblkno;
540
541 LOGSYNC_LOCK(log, flags);
542 if (mp->lsn != 0) {
543 /* inherit older/smaller lsn */
544 logdiff(diffp, mp->lsn, log);
545 if (difft < diffp) {
546 mp->lsn = lsn;
547
548 /* move bp after tblock in logsync list */
549 list_move(&mp->synclist, &tblk->synclist);
550 }
551
552 /* inherit younger/larger clsn */
553 logdiff(difft, tblk->clsn, log);
554 logdiff(diffp, mp->clsn, log);
555 if (difft > diffp)
556 mp->clsn = tblk->clsn;
557 } else {
558 mp->log = log;
559 mp->lsn = lsn;
560
561 /* insert bp after tblock in logsync list */
562 log->count++;
563 list_add(&mp->synclist, &tblk->synclist);
564
565 mp->clsn = tblk->clsn;
566 }
567 LOGSYNC_UNLOCK(log, flags);
568 }
569
570 /* write the last buffer. */
571 if (mp) {
572 write_metapage(mp);
573 }
574
575 return (0);
576}
577
578
579/*
580 * NAME: dbNextAG()
581 *
582 * FUNCTION: find the preferred allocation group for new allocations.
583 *
584 * Within the allocation groups, we maintain a preferred
585 * allocation group which consists of a group with at least
586 * average free space. It is the preferred group that we target
587 * new inode allocation towards. The tie-in between inode
588 * allocation and block allocation occurs as we allocate the
589 * first (data) block of an inode and specify the inode (block)
590 * as the allocation hint for this block.
591 *
592 * We try to avoid having more than one open file growing in
593 * an allocation group, as this will lead to fragmentation.
594 * This differs from the old OS/2 method of trying to keep
595 * empty ags around for large allocations.
596 *
597 * PARAMETERS:
598 * ipbmap - pointer to in-core inode for the block map.
599 *
600 * RETURN VALUES:
601 * the preferred allocation group number.
602 */
603int dbNextAG(struct inode *ipbmap)
604{
605 s64 avgfree;
606 int agpref;
607 s64 hwm = 0;
608 int i;
609 int next_best = -1;
610 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
611
612 BMAP_LOCK(bmp);
613
614 /* determine the average number of free blocks within the ags. */
615 avgfree = (u32)bmp->db_nfree / bmp->db_numag;
616
617 /*
618 * if the current preferred ag does not have an active allocator
619 * and has at least average freespace, return it
620 */
621 agpref = bmp->db_agpref;
622 if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
623 (bmp->db_agfree[agpref] >= avgfree))
624 goto unlock;
625
626 /* From the last preferred ag, find the next one with at least
627 * average free space.
628 */
629 for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
630 if (agpref == bmp->db_numag)
631 agpref = 0;
632
633 if (atomic_read(&bmp->db_active[agpref]))
634 /* open file is currently growing in this ag */
635 continue;
636 if (bmp->db_agfree[agpref] >= avgfree) {
637 /* Return this one */
638 bmp->db_agpref = agpref;
639 goto unlock;
640 } else if (bmp->db_agfree[agpref] > hwm) {
641 /* Less than avg. freespace, but best so far */
642 hwm = bmp->db_agfree[agpref];
643 next_best = agpref;
644 }
645 }
646
647 /*
648 * If no inactive ag was found with average freespace, use the
649 * next best
650 */
651 if (next_best != -1)
652 bmp->db_agpref = next_best;
653 /* else leave db_agpref unchanged */
654unlock:
655 BMAP_UNLOCK(bmp);
656
657 /* return the preferred group.
658 */
659 return (bmp->db_agpref);
660}
661
662/*
663 * NAME: dbAlloc()
664 *
665 * FUNCTION: attempt to allocate a specified number of contiguous free
666 * blocks from the working allocation block map.
667 *
668 * the block allocation policy uses hints and a multi-step
669 * approach.
670 *
671 * for allocation requests smaller than the number of blocks
672 * per dmap, we first try to allocate the new blocks
673 * immediately following the hint. if these blocks are not
674 * available, we try to allocate blocks near the hint. if
675 * no blocks near the hint are available, we next try to
676 * allocate within the same dmap as contains the hint.
677 *
678 * if no blocks are available in the dmap or the allocation
679 * request is larger than the dmap size, we try to allocate
680 * within the same allocation group as contains the hint. if
681 * this does not succeed, we finally try to allocate anywhere
682 * within the aggregate.
683 *
684 * we also try to allocate anywhere within the aggregate for
685 * for allocation requests larger than the allocation group
686 * size or requests that specify no hint value.
687 *
688 * PARAMETERS:
689 * ip - pointer to in-core inode;
690 * hint - allocation hint.
691 * nblocks - number of contiguous blocks in the range.
692 * results - on successful return, set to the starting block number
693 * of the newly allocated contiguous range.
694 *
695 * RETURN VALUES:
696 * 0 - success
697 * -ENOSPC - insufficient disk resources
698 * -EIO - i/o error
699 */
700int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
701{
702 int rc, agno;
703 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
704 struct bmap *bmp;
705 struct metapage *mp;
706 s64 lblkno, blkno;
707 struct dmap *dp;
708 int l2nb;
709 s64 mapSize;
710 int writers;
711
712 /* assert that nblocks is valid */
713 assert(nblocks > 0);
714
715 /* get the log2 number of blocks to be allocated.
716 * if the number of blocks is not a log2 multiple,
717 * it will be rounded up to the next log2 multiple.
718 */
719 l2nb = BLKSTOL2(nblocks);
720
721 bmp = JFS_SBI(ip->i_sb)->bmap;
722
723 mapSize = bmp->db_mapsize;
724
725 /* the hint should be within the map */
726 if (hint >= mapSize) {
727 jfs_error(ip->i_sb, "the hint is outside the map\n");
728 return -EIO;
729 }
730
731 /* if the number of blocks to be allocated is greater than the
732 * allocation group size, try to allocate anywhere.
733 */
734 if (l2nb > bmp->db_agl2size) {
735 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
736
737 rc = dbAllocAny(bmp, nblocks, l2nb, results);
738
739 goto write_unlock;
740 }
741
742 /*
743 * If no hint, let dbNextAG recommend an allocation group
744 */
745 if (hint == 0)
746 goto pref_ag;
747
748 /* we would like to allocate close to the hint. adjust the
749 * hint to the block following the hint since the allocators
750 * will start looking for free space starting at this point.
751 */
752 blkno = hint + 1;
753
754 if (blkno >= bmp->db_mapsize)
755 goto pref_ag;
756
757 agno = blkno >> bmp->db_agl2size;
758
759 /* check if blkno crosses over into a new allocation group.
760 * if so, check if we should allow allocations within this
761 * allocation group.
762 */
763 if ((blkno & (bmp->db_agsize - 1)) == 0)
764 /* check if the AG is currently being written to.
765 * if so, call dbNextAG() to find a non-busy
766 * AG with sufficient free space.
767 */
768 if (atomic_read(&bmp->db_active[agno]))
769 goto pref_ag;
770
771 /* check if the allocation request size can be satisfied from a
772 * single dmap. if so, try to allocate from the dmap containing
773 * the hint using a tiered strategy.
774 */
775 if (nblocks <= BPERDMAP) {
776 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
777
778 /* get the buffer for the dmap containing the hint.
779 */
780 rc = -EIO;
781 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
782 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
783 if (mp == NULL)
784 goto read_unlock;
785
786 dp = (struct dmap *) mp->data;
787
788 /* first, try to satisfy the allocation request with the
789 * blocks beginning at the hint.
790 */
791 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
792 != -ENOSPC) {
793 if (rc == 0) {
794 *results = blkno;
795 mark_metapage_dirty(mp);
796 }
797
798 release_metapage(mp);
799 goto read_unlock;
800 }
801
802 writers = atomic_read(&bmp->db_active[agno]);
803 if ((writers > 1) ||
804 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
805 /*
806 * Someone else is writing in this allocation
807 * group. To avoid fragmenting, try another ag
808 */
809 release_metapage(mp);
810 IREAD_UNLOCK(ipbmap);
811 goto pref_ag;
812 }
813
814 /* next, try to satisfy the allocation request with blocks
815 * near the hint.
816 */
817 if ((rc =
818 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
819 != -ENOSPC) {
820 if (rc == 0)
821 mark_metapage_dirty(mp);
822
823 release_metapage(mp);
824 goto read_unlock;
825 }
826
827 /* try to satisfy the allocation request with blocks within
828 * the same dmap as the hint.
829 */
830 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
831 != -ENOSPC) {
832 if (rc == 0)
833 mark_metapage_dirty(mp);
834
835 release_metapage(mp);
836 goto read_unlock;
837 }
838
839 release_metapage(mp);
840 IREAD_UNLOCK(ipbmap);
841 }
842
843 /* try to satisfy the allocation request with blocks within
844 * the same allocation group as the hint.
845 */
846 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
847 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
848 goto write_unlock;
849
850 IWRITE_UNLOCK(ipbmap);
851
852
853 pref_ag:
854 /*
855 * Let dbNextAG recommend a preferred allocation group
856 */
857 agno = dbNextAG(ipbmap);
858 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
859
860 /* Try to allocate within this allocation group. if that fails, try to
861 * allocate anywhere in the map.
862 */
863 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
864 rc = dbAllocAny(bmp, nblocks, l2nb, results);
865
866 write_unlock:
867 IWRITE_UNLOCK(ipbmap);
868
869 return (rc);
870
871 read_unlock:
872 IREAD_UNLOCK(ipbmap);
873
874 return (rc);
875}
876
877#ifdef _NOTYET
878/*
879 * NAME: dbAllocExact()
880 *
881 * FUNCTION: try to allocate the requested extent;
882 *
883 * PARAMETERS:
884 * ip - pointer to in-core inode;
885 * blkno - extent address;
886 * nblocks - extent length;
887 *
888 * RETURN VALUES:
889 * 0 - success
890 * -ENOSPC - insufficient disk resources
891 * -EIO - i/o error
892 */
893int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
894{
895 int rc;
896 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
897 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
898 struct dmap *dp;
899 s64 lblkno;
900 struct metapage *mp;
901
902 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
903
904 /*
905 * validate extent request:
906 *
907 * note: defragfs policy:
908 * max 64 blocks will be moved.
909 * allocation request size must be satisfied from a single dmap.
910 */
911 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
912 IREAD_UNLOCK(ipbmap);
913 return -EINVAL;
914 }
915
916 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
917 /* the free space is no longer available */
918 IREAD_UNLOCK(ipbmap);
919 return -ENOSPC;
920 }
921
922 /* read in the dmap covering the extent */
923 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
924 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
925 if (mp == NULL) {
926 IREAD_UNLOCK(ipbmap);
927 return -EIO;
928 }
929 dp = (struct dmap *) mp->data;
930
931 /* try to allocate the requested extent */
932 rc = dbAllocNext(bmp, dp, blkno, nblocks);
933
934 IREAD_UNLOCK(ipbmap);
935
936 if (rc == 0)
937 mark_metapage_dirty(mp);
938
939 release_metapage(mp);
940
941 return (rc);
942}
943#endif /* _NOTYET */
944
945/*
946 * NAME: dbReAlloc()
947 *
948 * FUNCTION: attempt to extend a current allocation by a specified
949 * number of blocks.
950 *
951 * this routine attempts to satisfy the allocation request
952 * by first trying to extend the existing allocation in
953 * place by allocating the additional blocks as the blocks
954 * immediately following the current allocation. if these
955 * blocks are not available, this routine will attempt to
956 * allocate a new set of contiguous blocks large enough
957 * to cover the existing allocation plus the additional
958 * number of blocks required.
959 *
960 * PARAMETERS:
961 * ip - pointer to in-core inode requiring allocation.
962 * blkno - starting block of the current allocation.
963 * nblocks - number of contiguous blocks within the current
964 * allocation.
965 * addnblocks - number of blocks to add to the allocation.
966 * results - on successful return, set to the starting block number
967 * of the existing allocation if the existing allocation
968 * was extended in place or to a newly allocated contiguous
969 * range if the existing allocation could not be extended
970 * in place.
971 *
972 * RETURN VALUES:
973 * 0 - success
974 * -ENOSPC - insufficient disk resources
975 * -EIO - i/o error
976 */
977int
978dbReAlloc(struct inode *ip,
979 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
980{
981 int rc;
982
983 /* try to extend the allocation in place.
984 */
985 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
986 *results = blkno;
987 return (0);
988 } else {
989 if (rc != -ENOSPC)
990 return (rc);
991 }
992
993 /* could not extend the allocation in place, so allocate a
994 * new set of blocks for the entire request (i.e. try to get
995 * a range of contiguous blocks large enough to cover the
996 * existing allocation plus the additional blocks.)
997 */
998 return (dbAlloc
999 (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
1000}
1001
1002
1003/*
1004 * NAME: dbExtend()
1005 *
1006 * FUNCTION: attempt to extend a current allocation by a specified
1007 * number of blocks.
1008 *
1009 * this routine attempts to satisfy the allocation request
1010 * by first trying to extend the existing allocation in
1011 * place by allocating the additional blocks as the blocks
1012 * immediately following the current allocation.
1013 *
1014 * PARAMETERS:
1015 * ip - pointer to in-core inode requiring allocation.
1016 * blkno - starting block of the current allocation.
1017 * nblocks - number of contiguous blocks within the current
1018 * allocation.
1019 * addnblocks - number of blocks to add to the allocation.
1020 *
1021 * RETURN VALUES:
1022 * 0 - success
1023 * -ENOSPC - insufficient disk resources
1024 * -EIO - i/o error
1025 */
1026static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1027{
1028 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1029 s64 lblkno, lastblkno, extblkno;
1030 uint rel_block;
1031 struct metapage *mp;
1032 struct dmap *dp;
1033 int rc;
1034 struct inode *ipbmap = sbi->ipbmap;
1035 struct bmap *bmp;
1036
1037 /*
1038 * We don't want a non-aligned extent to cross a page boundary
1039 */
1040 if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1041 (rel_block + nblocks + addnblocks > sbi->nbperpage))
1042 return -ENOSPC;
1043
1044 /* get the last block of the current allocation */
1045 lastblkno = blkno + nblocks - 1;
1046
1047 /* determine the block number of the block following
1048 * the existing allocation.
1049 */
1050 extblkno = lastblkno + 1;
1051
1052 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
1053
1054 /* better be within the file system */
1055 bmp = sbi->bmap;
1056 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1057 IREAD_UNLOCK(ipbmap);
1058 jfs_error(ip->i_sb, "the block is outside the filesystem\n");
1059 return -EIO;
1060 }
1061
1062 /* we'll attempt to extend the current allocation in place by
1063 * allocating the additional blocks as the blocks immediately
1064 * following the current allocation. we only try to extend the
1065 * current allocation in place if the number of additional blocks
1066 * can fit into a dmap, the last block of the current allocation
1067 * is not the last block of the file system, and the start of the
1068 * inplace extension is not on an allocation group boundary.
1069 */
1070 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1071 (extblkno & (bmp->db_agsize - 1)) == 0) {
1072 IREAD_UNLOCK(ipbmap);
1073 return -ENOSPC;
1074 }
1075
1076 /* get the buffer for the dmap containing the first block
1077 * of the extension.
1078 */
1079 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1080 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1081 if (mp == NULL) {
1082 IREAD_UNLOCK(ipbmap);
1083 return -EIO;
1084 }
1085
1086 dp = (struct dmap *) mp->data;
1087
1088 /* try to allocate the blocks immediately following the
1089 * current allocation.
1090 */
1091 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1092
1093 IREAD_UNLOCK(ipbmap);
1094
1095 /* were we successful ? */
1096 if (rc == 0)
1097 write_metapage(mp);
1098 else
1099 /* we were not successful */
1100 release_metapage(mp);
1101
1102 return (rc);
1103}
1104
1105
1106/*
1107 * NAME: dbAllocNext()
1108 *
1109 * FUNCTION: attempt to allocate the blocks of the specified block
1110 * range within a dmap.
1111 *
1112 * PARAMETERS:
1113 * bmp - pointer to bmap descriptor
1114 * dp - pointer to dmap.
1115 * blkno - starting block number of the range.
1116 * nblocks - number of contiguous free blocks of the range.
1117 *
1118 * RETURN VALUES:
1119 * 0 - success
1120 * -ENOSPC - insufficient disk resources
1121 * -EIO - i/o error
1122 *
1123 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1124 */
1125static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1126 int nblocks)
1127{
1128 int dbitno, word, rembits, nb, nwords, wbitno, nw;
1129 int l2size;
1130 s8 *leaf;
1131 u32 mask;
1132
1133 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1134 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1135 return -EIO;
1136 }
1137
1138 /* pick up a pointer to the leaves of the dmap tree.
1139 */
1140 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1141
1142 /* determine the bit number and word within the dmap of the
1143 * starting block.
1144 */
1145 dbitno = blkno & (BPERDMAP - 1);
1146 word = dbitno >> L2DBWORD;
1147
1148 /* check if the specified block range is contained within
1149 * this dmap.
1150 */
1151 if (dbitno + nblocks > BPERDMAP)
1152 return -ENOSPC;
1153
1154 /* check if the starting leaf indicates that anything
1155 * is free.
1156 */
1157 if (leaf[word] == NOFREE)
1158 return -ENOSPC;
1159
1160 /* check the dmaps words corresponding to block range to see
1161 * if the block range is free. not all bits of the first and
1162 * last words may be contained within the block range. if this
1163 * is the case, we'll work against those words (i.e. partial first
1164 * and/or last) on an individual basis (a single pass) and examine
1165 * the actual bits to determine if they are free. a single pass
1166 * will be used for all dmap words fully contained within the
1167 * specified range. within this pass, the leaves of the dmap
1168 * tree will be examined to determine if the blocks are free. a
1169 * single leaf may describe the free space of multiple dmap
1170 * words, so we may visit only a subset of the actual leaves
1171 * corresponding to the dmap words of the block range.
1172 */
1173 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1174 /* determine the bit number within the word and
1175 * the number of bits within the word.
1176 */
1177 wbitno = dbitno & (DBWORD - 1);
1178 nb = min(rembits, DBWORD - wbitno);
1179
1180 /* check if only part of the word is to be examined.
1181 */
1182 if (nb < DBWORD) {
1183 /* check if the bits are free.
1184 */
1185 mask = (ONES << (DBWORD - nb) >> wbitno);
1186 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1187 return -ENOSPC;
1188
1189 word += 1;
1190 } else {
1191 /* one or more dmap words are fully contained
1192 * within the block range. determine how many
1193 * words and how many bits.
1194 */
1195 nwords = rembits >> L2DBWORD;
1196 nb = nwords << L2DBWORD;
1197
1198 /* now examine the appropriate leaves to determine
1199 * if the blocks are free.
1200 */
1201 while (nwords > 0) {
1202 /* does the leaf describe any free space ?
1203 */
1204 if (leaf[word] < BUDMIN)
1205 return -ENOSPC;
1206
1207 /* determine the l2 number of bits provided
1208 * by this leaf.
1209 */
1210 l2size =
1211 min_t(int, leaf[word], NLSTOL2BSZ(nwords));
1212
1213 /* determine how many words were handled.
1214 */
1215 nw = BUDSIZE(l2size, BUDMIN);
1216
1217 nwords -= nw;
1218 word += nw;
1219 }
1220 }
1221 }
1222
1223 /* allocate the blocks.
1224 */
1225 return (dbAllocDmap(bmp, dp, blkno, nblocks));
1226}
1227
1228
1229/*
1230 * NAME: dbAllocNear()
1231 *
1232 * FUNCTION: attempt to allocate a number of contiguous free blocks near
1233 * a specified block (hint) within a dmap.
1234 *
1235 * starting with the dmap leaf that covers the hint, we'll
1236 * check the next four contiguous leaves for sufficient free
1237 * space. if sufficient free space is found, we'll allocate
1238 * the desired free space.
1239 *
1240 * PARAMETERS:
1241 * bmp - pointer to bmap descriptor
1242 * dp - pointer to dmap.
1243 * blkno - block number to allocate near.
1244 * nblocks - actual number of contiguous free blocks desired.
1245 * l2nb - log2 number of contiguous free blocks desired.
1246 * results - on successful return, set to the starting block number
1247 * of the newly allocated range.
1248 *
1249 * RETURN VALUES:
1250 * 0 - success
1251 * -ENOSPC - insufficient disk resources
1252 * -EIO - i/o error
1253 *
1254 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1255 */
1256static int
1257dbAllocNear(struct bmap * bmp,
1258 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1259{
1260 int word, lword, rc;
1261 s8 *leaf;
1262
1263 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1264 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1265 return -EIO;
1266 }
1267
1268 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1269
1270 /* determine the word within the dmap that holds the hint
1271 * (i.e. blkno). also, determine the last word in the dmap
1272 * that we'll include in our examination.
1273 */
1274 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1275 lword = min(word + 4, LPERDMAP);
1276
1277 /* examine the leaves for sufficient free space.
1278 */
1279 for (; word < lword; word++) {
1280 /* does the leaf describe sufficient free space ?
1281 */
1282 if (leaf[word] < l2nb)
1283 continue;
1284
1285 /* determine the block number within the file system
1286 * of the first block described by this dmap word.
1287 */
1288 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1289
1290 /* if not all bits of the dmap word are free, get the
1291 * starting bit number within the dmap word of the required
1292 * string of free bits and adjust the block number with the
1293 * value.
1294 */
1295 if (leaf[word] < BUDMIN)
1296 blkno +=
1297 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1298
1299 /* allocate the blocks.
1300 */
1301 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1302 *results = blkno;
1303
1304 return (rc);
1305 }
1306
1307 return -ENOSPC;
1308}
1309
1310
1311/*
1312 * NAME: dbAllocAG()
1313 *
1314 * FUNCTION: attempt to allocate the specified number of contiguous
1315 * free blocks within the specified allocation group.
1316 *
1317 * unless the allocation group size is equal to the number
1318 * of blocks per dmap, the dmap control pages will be used to
1319 * find the required free space, if available. we start the
1320 * search at the highest dmap control page level which
1321 * distinctly describes the allocation group's free space
1322 * (i.e. the highest level at which the allocation group's
1323 * free space is not mixed in with that of any other group).
1324 * in addition, we start the search within this level at a
1325 * height of the dmapctl dmtree at which the nodes distinctly
1326 * describe the allocation group's free space. at this height,
1327 * the allocation group's free space may be represented by 1
1328 * or two sub-trees, depending on the allocation group size.
1329 * we search the top nodes of these subtrees left to right for
1330 * sufficient free space. if sufficient free space is found,
1331 * the subtree is searched to find the leftmost leaf that
1332 * has free space. once we have made it to the leaf, we
1333 * move the search to the next lower level dmap control page
1334 * corresponding to this leaf. we continue down the dmap control
1335 * pages until we find the dmap that contains or starts the
1336 * sufficient free space and we allocate at this dmap.
1337 *
1338 * if the allocation group size is equal to the dmap size,
1339 * we'll start at the dmap corresponding to the allocation
1340 * group and attempt the allocation at this level.
1341 *
1342 * the dmap control page search is also not performed if the
1343 * allocation group is completely free and we go to the first
1344 * dmap of the allocation group to do the allocation. this is
1345 * done because the allocation group may be part (not the first
1346 * part) of a larger binary buddy system, causing the dmap
1347 * control pages to indicate no free space (NOFREE) within
1348 * the allocation group.
1349 *
1350 * PARAMETERS:
1351 * bmp - pointer to bmap descriptor
1352 * agno - allocation group number.
1353 * nblocks - actual number of contiguous free blocks desired.
1354 * l2nb - log2 number of contiguous free blocks desired.
1355 * results - on successful return, set to the starting block number
1356 * of the newly allocated range.
1357 *
1358 * RETURN VALUES:
1359 * 0 - success
1360 * -ENOSPC - insufficient disk resources
1361 * -EIO - i/o error
1362 *
1363 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1364 */
1365static int
1366dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1367{
1368 struct metapage *mp;
1369 struct dmapctl *dcp;
1370 int rc, ti, i, k, m, n, agperlev;
1371 s64 blkno, lblkno;
1372 int budmin;
1373
1374 /* allocation request should not be for more than the
1375 * allocation group size.
1376 */
1377 if (l2nb > bmp->db_agl2size) {
1378 jfs_error(bmp->db_ipbmap->i_sb,
1379 "allocation request is larger than the allocation group size\n");
1380 return -EIO;
1381 }
1382
1383 /* determine the starting block number of the allocation
1384 * group.
1385 */
1386 blkno = (s64) agno << bmp->db_agl2size;
1387
1388 /* check if the allocation group size is the minimum allocation
1389 * group size or if the allocation group is completely free. if
1390 * the allocation group size is the minimum size of BPERDMAP (i.e.
1391 * 1 dmap), there is no need to search the dmap control page (below)
1392 * that fully describes the allocation group since the allocation
1393 * group is already fully described by a dmap. in this case, we
1394 * just call dbAllocCtl() to search the dmap tree and allocate the
1395 * required space if available.
1396 *
1397 * if the allocation group is completely free, dbAllocCtl() is
1398 * also called to allocate the required space. this is done for
1399 * two reasons. first, it makes no sense searching the dmap control
1400 * pages for free space when we know that free space exists. second,
1401 * the dmap control pages may indicate that the allocation group
1402 * has no free space if the allocation group is part (not the first
1403 * part) of a larger binary buddy system.
1404 */
1405 if (bmp->db_agsize == BPERDMAP
1406 || bmp->db_agfree[agno] == bmp->db_agsize) {
1407 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1408 if ((rc == -ENOSPC) &&
1409 (bmp->db_agfree[agno] == bmp->db_agsize)) {
1410 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1411 (unsigned long long) blkno,
1412 (unsigned long long) nblocks);
1413 jfs_error(bmp->db_ipbmap->i_sb,
1414 "dbAllocCtl failed in free AG\n");
1415 }
1416 return (rc);
1417 }
1418
1419 /* the buffer for the dmap control page that fully describes the
1420 * allocation group.
1421 */
1422 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1423 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1424 if (mp == NULL)
1425 return -EIO;
1426 dcp = (struct dmapctl *) mp->data;
1427 budmin = dcp->budmin;
1428
1429 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1430 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
1431 release_metapage(mp);
1432 return -EIO;
1433 }
1434
1435 /* search the subtree(s) of the dmap control page that describes
1436 * the allocation group, looking for sufficient free space. to begin,
1437 * determine how many allocation groups are represented in a dmap
1438 * control page at the control page level (i.e. L0, L1, L2) that
1439 * fully describes an allocation group. next, determine the starting
1440 * tree index of this allocation group within the control page.
1441 */
1442 agperlev =
1443 (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1444 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1445
1446 /* dmap control page trees fan-out by 4 and a single allocation
1447 * group may be described by 1 or 2 subtrees within the ag level
1448 * dmap control page, depending upon the ag size. examine the ag's
1449 * subtrees for sufficient free space, starting with the leftmost
1450 * subtree.
1451 */
1452 for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1453 /* is there sufficient free space ?
1454 */
1455 if (l2nb > dcp->stree[ti])
1456 continue;
1457
1458 /* sufficient free space found in a subtree. now search down
1459 * the subtree to find the leftmost leaf that describes this
1460 * free space.
1461 */
1462 for (k = bmp->db_agheight; k > 0; k--) {
1463 for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1464 if (l2nb <= dcp->stree[m + n]) {
1465 ti = m + n;
1466 break;
1467 }
1468 }
1469 if (n == 4) {
1470 jfs_error(bmp->db_ipbmap->i_sb,
1471 "failed descending stree\n");
1472 release_metapage(mp);
1473 return -EIO;
1474 }
1475 }
1476
1477 /* determine the block number within the file system
1478 * that corresponds to this leaf.
1479 */
1480 if (bmp->db_aglevel == 2)
1481 blkno = 0;
1482 else if (bmp->db_aglevel == 1)
1483 blkno &= ~(MAXL1SIZE - 1);
1484 else /* bmp->db_aglevel == 0 */
1485 blkno &= ~(MAXL0SIZE - 1);
1486
1487 blkno +=
1488 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1489
1490 /* release the buffer in preparation for going down
1491 * the next level of dmap control pages.
1492 */
1493 release_metapage(mp);
1494
1495 /* check if we need to continue to search down the lower
1496 * level dmap control pages. we need to if the number of
1497 * blocks required is less than maximum number of blocks
1498 * described at the next lower level.
1499 */
1500 if (l2nb < budmin) {
1501
1502 /* search the lower level dmap control pages to get
1503 * the starting block number of the dmap that
1504 * contains or starts off the free space.
1505 */
1506 if ((rc =
1507 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1508 &blkno))) {
1509 if (rc == -ENOSPC) {
1510 jfs_error(bmp->db_ipbmap->i_sb,
1511 "control page inconsistent\n");
1512 return -EIO;
1513 }
1514 return (rc);
1515 }
1516 }
1517
1518 /* allocate the blocks.
1519 */
1520 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1521 if (rc == -ENOSPC) {
1522 jfs_error(bmp->db_ipbmap->i_sb,
1523 "unable to allocate blocks\n");
1524 rc = -EIO;
1525 }
1526 return (rc);
1527 }
1528
1529 /* no space in the allocation group. release the buffer and
1530 * return -ENOSPC.
1531 */
1532 release_metapage(mp);
1533
1534 return -ENOSPC;
1535}
1536
1537
1538/*
1539 * NAME: dbAllocAny()
1540 *
1541 * FUNCTION: attempt to allocate the specified number of contiguous
1542 * free blocks anywhere in the file system.
1543 *
1544 * dbAllocAny() attempts to find the sufficient free space by
1545 * searching down the dmap control pages, starting with the
1546 * highest level (i.e. L0, L1, L2) control page. if free space
1547 * large enough to satisfy the desired free space is found, the
1548 * desired free space is allocated.
1549 *
1550 * PARAMETERS:
1551 * bmp - pointer to bmap descriptor
1552 * nblocks - actual number of contiguous free blocks desired.
1553 * l2nb - log2 number of contiguous free blocks desired.
1554 * results - on successful return, set to the starting block number
1555 * of the newly allocated range.
1556 *
1557 * RETURN VALUES:
1558 * 0 - success
1559 * -ENOSPC - insufficient disk resources
1560 * -EIO - i/o error
1561 *
1562 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1563 */
1564static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1565{
1566 int rc;
1567 s64 blkno = 0;
1568
1569 /* starting with the top level dmap control page, search
1570 * down the dmap control levels for sufficient free space.
1571 * if free space is found, dbFindCtl() returns the starting
1572 * block number of the dmap that contains or starts off the
1573 * range of free space.
1574 */
1575 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1576 return (rc);
1577
1578 /* allocate the blocks.
1579 */
1580 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1581 if (rc == -ENOSPC) {
1582 jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n");
1583 return -EIO;
1584 }
1585 return (rc);
1586}
1587
1588
1589/*
1590 * NAME: dbDiscardAG()
1591 *
1592 * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG
1593 *
1594 * algorithm:
1595 * 1) allocate blocks, as large as possible and save them
1596 * while holding IWRITE_LOCK on ipbmap
1597 * 2) trim all these saved block/length values
1598 * 3) mark the blocks free again
1599 *
1600 * benefit:
1601 * - we work only on one ag at some time, minimizing how long we
1602 * need to lock ipbmap
1603 * - reading / writing the fs is possible most time, even on
1604 * trimming
1605 *
1606 * downside:
1607 * - we write two times to the dmapctl and dmap pages
1608 * - but for me, this seems the best way, better ideas?
1609 * /TR 2012
1610 *
1611 * PARAMETERS:
1612 * ip - pointer to in-core inode
1613 * agno - ag to trim
1614 * minlen - minimum value of contiguous blocks
1615 *
1616 * RETURN VALUES:
1617 * s64 - actual number of blocks trimmed
1618 */
1619s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
1620{
1621 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
1622 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
1623 s64 nblocks, blkno;
1624 u64 trimmed = 0;
1625 int rc, l2nb;
1626 struct super_block *sb = ipbmap->i_sb;
1627
1628 struct range2trim {
1629 u64 blkno;
1630 u64 nblocks;
1631 } *totrim, *tt;
1632
1633 /* max blkno / nblocks pairs to trim */
1634 int count = 0, range_cnt;
1635 u64 max_ranges;
1636
1637 /* prevent others from writing new stuff here, while trimming */
1638 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
1639
1640 nblocks = bmp->db_agfree[agno];
1641 max_ranges = nblocks;
1642 do_div(max_ranges, minlen);
1643 range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
1644 totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS);
1645 if (totrim == NULL) {
1646 jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n");
1647 IWRITE_UNLOCK(ipbmap);
1648 return 0;
1649 }
1650
1651 tt = totrim;
1652 while (nblocks >= minlen) {
1653 l2nb = BLKSTOL2(nblocks);
1654
1655 /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
1656 rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
1657 if (rc == 0) {
1658 tt->blkno = blkno;
1659 tt->nblocks = nblocks;
1660 tt++; count++;
1661
1662 /* the whole ag is free, trim now */
1663 if (bmp->db_agfree[agno] == 0)
1664 break;
1665
1666 /* give a hint for the next while */
1667 nblocks = bmp->db_agfree[agno];
1668 continue;
1669 } else if (rc == -ENOSPC) {
1670 /* search for next smaller log2 block */
1671 l2nb = BLKSTOL2(nblocks) - 1;
1672 nblocks = 1 << l2nb;
1673 } else {
1674 /* Trim any already allocated blocks */
1675 jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
1676 break;
1677 }
1678
1679 /* check, if our trim array is full */
1680 if (unlikely(count >= range_cnt - 1))
1681 break;
1682 }
1683 IWRITE_UNLOCK(ipbmap);
1684
1685 tt->nblocks = 0; /* mark the current end */
1686 for (tt = totrim; tt->nblocks != 0; tt++) {
1687 /* when mounted with online discard, dbFree() will
1688 * call jfs_issue_discard() itself */
1689 if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
1690 jfs_issue_discard(ip, tt->blkno, tt->nblocks);
1691 dbFree(ip, tt->blkno, tt->nblocks);
1692 trimmed += tt->nblocks;
1693 }
1694 kfree(totrim);
1695
1696 return trimmed;
1697}
1698
1699/*
1700 * NAME: dbFindCtl()
1701 *
1702 * FUNCTION: starting at a specified dmap control page level and block
1703 * number, search down the dmap control levels for a range of
1704 * contiguous free blocks large enough to satisfy an allocation
1705 * request for the specified number of free blocks.
1706 *
1707 * if sufficient contiguous free blocks are found, this routine
1708 * returns the starting block number within a dmap page that
1709 * contains or starts a range of contiqious free blocks that
1710 * is sufficient in size.
1711 *
1712 * PARAMETERS:
1713 * bmp - pointer to bmap descriptor
1714 * level - starting dmap control page level.
1715 * l2nb - log2 number of contiguous free blocks desired.
1716 * *blkno - on entry, starting block number for conducting the search.
1717 * on successful return, the first block within a dmap page
1718 * that contains or starts a range of contiguous free blocks.
1719 *
1720 * RETURN VALUES:
1721 * 0 - success
1722 * -ENOSPC - insufficient disk resources
1723 * -EIO - i/o error
1724 *
1725 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1726 */
1727static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1728{
1729 int rc, leafidx, lev;
1730 s64 b, lblkno;
1731 struct dmapctl *dcp;
1732 int budmin;
1733 struct metapage *mp;
1734
1735 /* starting at the specified dmap control page level and block
1736 * number, search down the dmap control levels for the starting
1737 * block number of a dmap page that contains or starts off
1738 * sufficient free blocks.
1739 */
1740 for (lev = level, b = *blkno; lev >= 0; lev--) {
1741 /* get the buffer of the dmap control page for the block
1742 * number and level (i.e. L0, L1, L2).
1743 */
1744 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1745 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1746 if (mp == NULL)
1747 return -EIO;
1748 dcp = (struct dmapctl *) mp->data;
1749 budmin = dcp->budmin;
1750
1751 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1752 jfs_error(bmp->db_ipbmap->i_sb,
1753 "Corrupt dmapctl page\n");
1754 release_metapage(mp);
1755 return -EIO;
1756 }
1757
1758 /* search the tree within the dmap control page for
1759 * sufficient free space. if sufficient free space is found,
1760 * dbFindLeaf() returns the index of the leaf at which
1761 * free space was found.
1762 */
1763 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1764
1765 /* release the buffer.
1766 */
1767 release_metapage(mp);
1768
1769 /* space found ?
1770 */
1771 if (rc) {
1772 if (lev != level) {
1773 jfs_error(bmp->db_ipbmap->i_sb,
1774 "dmap inconsistent\n");
1775 return -EIO;
1776 }
1777 return -ENOSPC;
1778 }
1779
1780 /* adjust the block number to reflect the location within
1781 * the dmap control page (i.e. the leaf) at which free
1782 * space was found.
1783 */
1784 b += (((s64) leafidx) << budmin);
1785
1786 /* we stop the search at this dmap control page level if
1787 * the number of blocks required is greater than or equal
1788 * to the maximum number of blocks described at the next
1789 * (lower) level.
1790 */
1791 if (l2nb >= budmin)
1792 break;
1793 }
1794
1795 *blkno = b;
1796 return (0);
1797}
1798
1799
1800/*
1801 * NAME: dbAllocCtl()
1802 *
1803 * FUNCTION: attempt to allocate a specified number of contiguous
1804 * blocks starting within a specific dmap.
1805 *
1806 * this routine is called by higher level routines that search
1807 * the dmap control pages above the actual dmaps for contiguous
1808 * free space. the result of successful searches by these
1809 * routines are the starting block numbers within dmaps, with
1810 * the dmaps themselves containing the desired contiguous free
1811 * space or starting a contiguous free space of desired size
1812 * that is made up of the blocks of one or more dmaps. these
1813 * calls should not fail due to insufficent resources.
1814 *
1815 * this routine is called in some cases where it is not known
1816 * whether it will fail due to insufficient resources. more
1817 * specifically, this occurs when allocating from an allocation
1818 * group whose size is equal to the number of blocks per dmap.
1819 * in this case, the dmap control pages are not examined prior
1820 * to calling this routine (to save pathlength) and the call
1821 * might fail.
1822 *
1823 * for a request size that fits within a dmap, this routine relies
1824 * upon the dmap's dmtree to find the requested contiguous free
1825 * space. for request sizes that are larger than a dmap, the
1826 * requested free space will start at the first block of the
1827 * first dmap (i.e. blkno).
1828 *
1829 * PARAMETERS:
1830 * bmp - pointer to bmap descriptor
1831 * nblocks - actual number of contiguous free blocks to allocate.
1832 * l2nb - log2 number of contiguous free blocks to allocate.
1833 * blkno - starting block number of the dmap to start the allocation
1834 * from.
1835 * results - on successful return, set to the starting block number
1836 * of the newly allocated range.
1837 *
1838 * RETURN VALUES:
1839 * 0 - success
1840 * -ENOSPC - insufficient disk resources
1841 * -EIO - i/o error
1842 *
1843 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1844 */
1845static int
1846dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1847{
1848 int rc, nb;
1849 s64 b, lblkno, n;
1850 struct metapage *mp;
1851 struct dmap *dp;
1852
1853 /* check if the allocation request is confined to a single dmap.
1854 */
1855 if (l2nb <= L2BPERDMAP) {
1856 /* get the buffer for the dmap.
1857 */
1858 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1859 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1860 if (mp == NULL)
1861 return -EIO;
1862 dp = (struct dmap *) mp->data;
1863
1864 /* try to allocate the blocks.
1865 */
1866 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1867 if (rc == 0)
1868 mark_metapage_dirty(mp);
1869
1870 release_metapage(mp);
1871
1872 return (rc);
1873 }
1874
1875 /* allocation request involving multiple dmaps. it must start on
1876 * a dmap boundary.
1877 */
1878 assert((blkno & (BPERDMAP - 1)) == 0);
1879
1880 /* allocate the blocks dmap by dmap.
1881 */
1882 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1883 /* get the buffer for the dmap.
1884 */
1885 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1886 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1887 if (mp == NULL) {
1888 rc = -EIO;
1889 goto backout;
1890 }
1891 dp = (struct dmap *) mp->data;
1892
1893 /* the dmap better be all free.
1894 */
1895 if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1896 release_metapage(mp);
1897 jfs_error(bmp->db_ipbmap->i_sb,
1898 "the dmap is not all free\n");
1899 rc = -EIO;
1900 goto backout;
1901 }
1902
1903 /* determine how many blocks to allocate from this dmap.
1904 */
1905 nb = min_t(s64, n, BPERDMAP);
1906
1907 /* allocate the blocks from the dmap.
1908 */
1909 if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1910 release_metapage(mp);
1911 goto backout;
1912 }
1913
1914 /* write the buffer.
1915 */
1916 write_metapage(mp);
1917 }
1918
1919 /* set the results (starting block number) and return.
1920 */
1921 *results = blkno;
1922 return (0);
1923
1924 /* something failed in handling an allocation request involving
1925 * multiple dmaps. we'll try to clean up by backing out any
1926 * allocation that has already happened for this request. if
1927 * we fail in backing out the allocation, we'll mark the file
1928 * system to indicate that blocks have been leaked.
1929 */
1930 backout:
1931
1932 /* try to backout the allocations dmap by dmap.
1933 */
1934 for (n = nblocks - n, b = blkno; n > 0;
1935 n -= BPERDMAP, b += BPERDMAP) {
1936 /* get the buffer for this dmap.
1937 */
1938 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1939 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1940 if (mp == NULL) {
1941 /* could not back out. mark the file system
1942 * to indicate that we have leaked blocks.
1943 */
1944 jfs_error(bmp->db_ipbmap->i_sb,
1945 "I/O Error: Block Leakage\n");
1946 continue;
1947 }
1948 dp = (struct dmap *) mp->data;
1949
1950 /* free the blocks is this dmap.
1951 */
1952 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1953 /* could not back out. mark the file system
1954 * to indicate that we have leaked blocks.
1955 */
1956 release_metapage(mp);
1957 jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n");
1958 continue;
1959 }
1960
1961 /* write the buffer.
1962 */
1963 write_metapage(mp);
1964 }
1965
1966 return (rc);
1967}
1968
1969
1970/*
1971 * NAME: dbAllocDmapLev()
1972 *
1973 * FUNCTION: attempt to allocate a specified number of contiguous blocks
1974 * from a specified dmap.
1975 *
1976 * this routine checks if the contiguous blocks are available.
1977 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1978 * returned.
1979 *
1980 * PARAMETERS:
1981 * mp - pointer to bmap descriptor
1982 * dp - pointer to dmap to attempt to allocate blocks from.
1983 * l2nb - log2 number of contiguous block desired.
1984 * nblocks - actual number of contiguous block desired.
1985 * results - on successful return, set to the starting block number
1986 * of the newly allocated range.
1987 *
1988 * RETURN VALUES:
1989 * 0 - success
1990 * -ENOSPC - insufficient disk resources
1991 * -EIO - i/o error
1992 *
1993 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1994 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1995 */
1996static int
1997dbAllocDmapLev(struct bmap * bmp,
1998 struct dmap * dp, int nblocks, int l2nb, s64 * results)
1999{
2000 s64 blkno;
2001 int leafidx, rc;
2002
2003 /* can't be more than a dmaps worth of blocks */
2004 assert(l2nb <= L2BPERDMAP);
2005
2006 /* search the tree within the dmap page for sufficient
2007 * free space. if sufficient free space is found, dbFindLeaf()
2008 * returns the index of the leaf at which free space was found.
2009 */
2010 if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
2011 return -ENOSPC;
2012
2013 /* determine the block number within the file system corresponding
2014 * to the leaf at which free space was found.
2015 */
2016 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
2017
2018 /* if not all bits of the dmap word are free, get the starting
2019 * bit number within the dmap word of the required string of free
2020 * bits and adjust the block number with this value.
2021 */
2022 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
2023 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
2024
2025 /* allocate the blocks */
2026 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
2027 *results = blkno;
2028
2029 return (rc);
2030}
2031
2032
2033/*
2034 * NAME: dbAllocDmap()
2035 *
2036 * FUNCTION: adjust the disk allocation map to reflect the allocation
2037 * of a specified block range within a dmap.
2038 *
2039 * this routine allocates the specified blocks from the dmap
2040 * through a call to dbAllocBits(). if the allocation of the
2041 * block range causes the maximum string of free blocks within
2042 * the dmap to change (i.e. the value of the root of the dmap's
2043 * dmtree), this routine will cause this change to be reflected
2044 * up through the appropriate levels of the dmap control pages
2045 * by a call to dbAdjCtl() for the L0 dmap control page that
2046 * covers this dmap.
2047 *
2048 * PARAMETERS:
2049 * bmp - pointer to bmap descriptor
2050 * dp - pointer to dmap to allocate the block range from.
2051 * blkno - starting block number of the block to be allocated.
2052 * nblocks - number of blocks to be allocated.
2053 *
2054 * RETURN VALUES:
2055 * 0 - success
2056 * -EIO - i/o error
2057 *
2058 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2059 */
2060static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2061 int nblocks)
2062{
2063 s8 oldroot;
2064 int rc;
2065
2066 /* save the current value of the root (i.e. maximum free string)
2067 * of the dmap tree.
2068 */
2069 oldroot = dp->tree.stree[ROOT];
2070
2071 /* allocate the specified (blocks) bits */
2072 dbAllocBits(bmp, dp, blkno, nblocks);
2073
2074 /* if the root has not changed, done. */
2075 if (dp->tree.stree[ROOT] == oldroot)
2076 return (0);
2077
2078 /* root changed. bubble the change up to the dmap control pages.
2079 * if the adjustment of the upper level control pages fails,
2080 * backout the bit allocation (thus making everything consistent).
2081 */
2082 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
2083 dbFreeBits(bmp, dp, blkno, nblocks);
2084
2085 return (rc);
2086}
2087
2088
2089/*
2090 * NAME: dbFreeDmap()
2091 *
2092 * FUNCTION: adjust the disk allocation map to reflect the allocation
2093 * of a specified block range within a dmap.
2094 *
2095 * this routine frees the specified blocks from the dmap through
2096 * a call to dbFreeBits(). if the deallocation of the block range
2097 * causes the maximum string of free blocks within the dmap to
2098 * change (i.e. the value of the root of the dmap's dmtree), this
2099 * routine will cause this change to be reflected up through the
2100 * appropriate levels of the dmap control pages by a call to
2101 * dbAdjCtl() for the L0 dmap control page that covers this dmap.
2102 *
2103 * PARAMETERS:
2104 * bmp - pointer to bmap descriptor
2105 * dp - pointer to dmap to free the block range from.
2106 * blkno - starting block number of the block to be freed.
2107 * nblocks - number of blocks to be freed.
2108 *
2109 * RETURN VALUES:
2110 * 0 - success
2111 * -EIO - i/o error
2112 *
2113 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2114 */
2115static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2116 int nblocks)
2117{
2118 s8 oldroot;
2119 int rc = 0, word;
2120
2121 /* save the current value of the root (i.e. maximum free string)
2122 * of the dmap tree.
2123 */
2124 oldroot = dp->tree.stree[ROOT];
2125
2126 /* free the specified (blocks) bits */
2127 rc = dbFreeBits(bmp, dp, blkno, nblocks);
2128
2129 /* if error or the root has not changed, done. */
2130 if (rc || (dp->tree.stree[ROOT] == oldroot))
2131 return (rc);
2132
2133 /* root changed. bubble the change up to the dmap control pages.
2134 * if the adjustment of the upper level control pages fails,
2135 * backout the deallocation.
2136 */
2137 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2138 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2139
2140 /* as part of backing out the deallocation, we will have
2141 * to back split the dmap tree if the deallocation caused
2142 * the freed blocks to become part of a larger binary buddy
2143 * system.
2144 */
2145 if (dp->tree.stree[word] == NOFREE)
2146 dbBackSplit((dmtree_t *) & dp->tree, word);
2147
2148 dbAllocBits(bmp, dp, blkno, nblocks);
2149 }
2150
2151 return (rc);
2152}
2153
2154
2155/*
2156 * NAME: dbAllocBits()
2157 *
2158 * FUNCTION: allocate a specified block range from a dmap.
2159 *
2160 * this routine updates the dmap to reflect the working
2161 * state allocation of the specified block range. it directly
2162 * updates the bits of the working map and causes the adjustment
2163 * of the binary buddy system described by the dmap's dmtree
2164 * leaves to reflect the bits allocated. it also causes the
2165 * dmap's dmtree, as a whole, to reflect the allocated range.
2166 *
2167 * PARAMETERS:
2168 * bmp - pointer to bmap descriptor
2169 * dp - pointer to dmap to allocate bits from.
2170 * blkno - starting block number of the bits to be allocated.
2171 * nblocks - number of bits to be allocated.
2172 *
2173 * RETURN VALUES: none
2174 *
2175 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2176 */
2177static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2178 int nblocks)
2179{
2180 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2181 dmtree_t *tp = (dmtree_t *) & dp->tree;
2182 int size;
2183 s8 *leaf;
2184
2185 /* pick up a pointer to the leaves of the dmap tree */
2186 leaf = dp->tree.stree + LEAFIND;
2187
2188 /* determine the bit number and word within the dmap of the
2189 * starting block.
2190 */
2191 dbitno = blkno & (BPERDMAP - 1);
2192 word = dbitno >> L2DBWORD;
2193
2194 /* block range better be within the dmap */
2195 assert(dbitno + nblocks <= BPERDMAP);
2196
2197 /* allocate the bits of the dmap's words corresponding to the block
2198 * range. not all bits of the first and last words may be contained
2199 * within the block range. if this is the case, we'll work against
2200 * those words (i.e. partial first and/or last) on an individual basis
2201 * (a single pass), allocating the bits of interest by hand and
2202 * updating the leaf corresponding to the dmap word. a single pass
2203 * will be used for all dmap words fully contained within the
2204 * specified range. within this pass, the bits of all fully contained
2205 * dmap words will be marked as free in a single shot and the leaves
2206 * will be updated. a single leaf may describe the free space of
2207 * multiple dmap words, so we may update only a subset of the actual
2208 * leaves corresponding to the dmap words of the block range.
2209 */
2210 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2211 /* determine the bit number within the word and
2212 * the number of bits within the word.
2213 */
2214 wbitno = dbitno & (DBWORD - 1);
2215 nb = min(rembits, DBWORD - wbitno);
2216
2217 /* check if only part of a word is to be allocated.
2218 */
2219 if (nb < DBWORD) {
2220 /* allocate (set to 1) the appropriate bits within
2221 * this dmap word.
2222 */
2223 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2224 >> wbitno);
2225
2226 /* update the leaf for this dmap word. in addition
2227 * to setting the leaf value to the binary buddy max
2228 * of the updated dmap word, dbSplit() will split
2229 * the binary system of the leaves if need be.
2230 */
2231 dbSplit(tp, word, BUDMIN,
2232 dbMaxBud((u8 *) & dp->wmap[word]));
2233
2234 word += 1;
2235 } else {
2236 /* one or more dmap words are fully contained
2237 * within the block range. determine how many
2238 * words and allocate (set to 1) the bits of these
2239 * words.
2240 */
2241 nwords = rembits >> L2DBWORD;
2242 memset(&dp->wmap[word], (int) ONES, nwords * 4);
2243
2244 /* determine how many bits.
2245 */
2246 nb = nwords << L2DBWORD;
2247
2248 /* now update the appropriate leaves to reflect
2249 * the allocated words.
2250 */
2251 for (; nwords > 0; nwords -= nw) {
2252 if (leaf[word] < BUDMIN) {
2253 jfs_error(bmp->db_ipbmap->i_sb,
2254 "leaf page corrupt\n");
2255 break;
2256 }
2257
2258 /* determine what the leaf value should be
2259 * updated to as the minimum of the l2 number
2260 * of bits being allocated and the l2 number
2261 * of bits currently described by this leaf.
2262 */
2263 size = min_t(int, leaf[word],
2264 NLSTOL2BSZ(nwords));
2265
2266 /* update the leaf to reflect the allocation.
2267 * in addition to setting the leaf value to
2268 * NOFREE, dbSplit() will split the binary
2269 * system of the leaves to reflect the current
2270 * allocation (size).
2271 */
2272 dbSplit(tp, word, size, NOFREE);
2273
2274 /* get the number of dmap words handled */
2275 nw = BUDSIZE(size, BUDMIN);
2276 word += nw;
2277 }
2278 }
2279 }
2280
2281 /* update the free count for this dmap */
2282 le32_add_cpu(&dp->nfree, -nblocks);
2283
2284 BMAP_LOCK(bmp);
2285
2286 /* if this allocation group is completely free,
2287 * update the maximum allocation group number if this allocation
2288 * group is the new max.
2289 */
2290 agno = blkno >> bmp->db_agl2size;
2291 if (agno > bmp->db_maxag)
2292 bmp->db_maxag = agno;
2293
2294 /* update the free count for the allocation group and map */
2295 bmp->db_agfree[agno] -= nblocks;
2296 bmp->db_nfree -= nblocks;
2297
2298 BMAP_UNLOCK(bmp);
2299}
2300
2301
2302/*
2303 * NAME: dbFreeBits()
2304 *
2305 * FUNCTION: free a specified block range from a dmap.
2306 *
2307 * this routine updates the dmap to reflect the working
2308 * state allocation of the specified block range. it directly
2309 * updates the bits of the working map and causes the adjustment
2310 * of the binary buddy system described by the dmap's dmtree
2311 * leaves to reflect the bits freed. it also causes the dmap's
2312 * dmtree, as a whole, to reflect the deallocated range.
2313 *
2314 * PARAMETERS:
2315 * bmp - pointer to bmap descriptor
2316 * dp - pointer to dmap to free bits from.
2317 * blkno - starting block number of the bits to be freed.
2318 * nblocks - number of bits to be freed.
2319 *
2320 * RETURN VALUES: 0 for success
2321 *
2322 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2323 */
2324static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2325 int nblocks)
2326{
2327 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2328 dmtree_t *tp = (dmtree_t *) & dp->tree;
2329 int rc = 0;
2330 int size;
2331
2332 /* determine the bit number and word within the dmap of the
2333 * starting block.
2334 */
2335 dbitno = blkno & (BPERDMAP - 1);
2336 word = dbitno >> L2DBWORD;
2337
2338 /* block range better be within the dmap.
2339 */
2340 assert(dbitno + nblocks <= BPERDMAP);
2341
2342 /* free the bits of the dmaps words corresponding to the block range.
2343 * not all bits of the first and last words may be contained within
2344 * the block range. if this is the case, we'll work against those
2345 * words (i.e. partial first and/or last) on an individual basis
2346 * (a single pass), freeing the bits of interest by hand and updating
2347 * the leaf corresponding to the dmap word. a single pass will be used
2348 * for all dmap words fully contained within the specified range.
2349 * within this pass, the bits of all fully contained dmap words will
2350 * be marked as free in a single shot and the leaves will be updated. a
2351 * single leaf may describe the free space of multiple dmap words,
2352 * so we may update only a subset of the actual leaves corresponding
2353 * to the dmap words of the block range.
2354 *
2355 * dbJoin() is used to update leaf values and will join the binary
2356 * buddy system of the leaves if the new leaf values indicate this
2357 * should be done.
2358 */
2359 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2360 /* determine the bit number within the word and
2361 * the number of bits within the word.
2362 */
2363 wbitno = dbitno & (DBWORD - 1);
2364 nb = min(rembits, DBWORD - wbitno);
2365
2366 /* check if only part of a word is to be freed.
2367 */
2368 if (nb < DBWORD) {
2369 /* free (zero) the appropriate bits within this
2370 * dmap word.
2371 */
2372 dp->wmap[word] &=
2373 cpu_to_le32(~(ONES << (DBWORD - nb)
2374 >> wbitno));
2375
2376 /* update the leaf for this dmap word.
2377 */
2378 rc = dbJoin(tp, word,
2379 dbMaxBud((u8 *) & dp->wmap[word]));
2380 if (rc)
2381 return rc;
2382
2383 word += 1;
2384 } else {
2385 /* one or more dmap words are fully contained
2386 * within the block range. determine how many
2387 * words and free (zero) the bits of these words.
2388 */
2389 nwords = rembits >> L2DBWORD;
2390 memset(&dp->wmap[word], 0, nwords * 4);
2391
2392 /* determine how many bits.
2393 */
2394 nb = nwords << L2DBWORD;
2395
2396 /* now update the appropriate leaves to reflect
2397 * the freed words.
2398 */
2399 for (; nwords > 0; nwords -= nw) {
2400 /* determine what the leaf value should be
2401 * updated to as the minimum of the l2 number
2402 * of bits being freed and the l2 (max) number
2403 * of bits that can be described by this leaf.
2404 */
2405 size =
2406 min(LITOL2BSZ
2407 (word, L2LPERDMAP, BUDMIN),
2408 NLSTOL2BSZ(nwords));
2409
2410 /* update the leaf.
2411 */
2412 rc = dbJoin(tp, word, size);
2413 if (rc)
2414 return rc;
2415
2416 /* get the number of dmap words handled.
2417 */
2418 nw = BUDSIZE(size, BUDMIN);
2419 word += nw;
2420 }
2421 }
2422 }
2423
2424 /* update the free count for this dmap.
2425 */
2426 le32_add_cpu(&dp->nfree, nblocks);
2427
2428 BMAP_LOCK(bmp);
2429
2430 /* update the free count for the allocation group and
2431 * map.
2432 */
2433 agno = blkno >> bmp->db_agl2size;
2434 bmp->db_nfree += nblocks;
2435 bmp->db_agfree[agno] += nblocks;
2436
2437 /* check if this allocation group is not completely free and
2438 * if it is currently the maximum (rightmost) allocation group.
2439 * if so, establish the new maximum allocation group number by
2440 * searching left for the first allocation group with allocation.
2441 */
2442 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2443 (agno == bmp->db_numag - 1 &&
2444 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2445 while (bmp->db_maxag > 0) {
2446 bmp->db_maxag -= 1;
2447 if (bmp->db_agfree[bmp->db_maxag] !=
2448 bmp->db_agsize)
2449 break;
2450 }
2451
2452 /* re-establish the allocation group preference if the
2453 * current preference is right of the maximum allocation
2454 * group.
2455 */
2456 if (bmp->db_agpref > bmp->db_maxag)
2457 bmp->db_agpref = bmp->db_maxag;
2458 }
2459
2460 BMAP_UNLOCK(bmp);
2461
2462 return 0;
2463}
2464
2465
2466/*
2467 * NAME: dbAdjCtl()
2468 *
2469 * FUNCTION: adjust a dmap control page at a specified level to reflect
2470 * the change in a lower level dmap or dmap control page's
2471 * maximum string of free blocks (i.e. a change in the root
2472 * of the lower level object's dmtree) due to the allocation
2473 * or deallocation of a range of blocks with a single dmap.
2474 *
2475 * on entry, this routine is provided with the new value of
2476 * the lower level dmap or dmap control page root and the
2477 * starting block number of the block range whose allocation
2478 * or deallocation resulted in the root change. this range
2479 * is respresented by a single leaf of the current dmapctl
2480 * and the leaf will be updated with this value, possibly
2481 * causing a binary buddy system within the leaves to be
2482 * split or joined. the update may also cause the dmapctl's
2483 * dmtree to be updated.
2484 *
2485 * if the adjustment of the dmap control page, itself, causes its
2486 * root to change, this change will be bubbled up to the next dmap
2487 * control level by a recursive call to this routine, specifying
2488 * the new root value and the next dmap control page level to
2489 * be adjusted.
2490 * PARAMETERS:
2491 * bmp - pointer to bmap descriptor
2492 * blkno - the first block of a block range within a dmap. it is
2493 * the allocation or deallocation of this block range that
2494 * requires the dmap control page to be adjusted.
2495 * newval - the new value of the lower level dmap or dmap control
2496 * page root.
2497 * alloc - 'true' if adjustment is due to an allocation.
2498 * level - current level of dmap control page (i.e. L0, L1, L2) to
2499 * be adjusted.
2500 *
2501 * RETURN VALUES:
2502 * 0 - success
2503 * -EIO - i/o error
2504 *
2505 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2506 */
2507static int
2508dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2509{
2510 struct metapage *mp;
2511 s8 oldroot;
2512 int oldval;
2513 s64 lblkno;
2514 struct dmapctl *dcp;
2515 int rc, leafno, ti;
2516
2517 /* get the buffer for the dmap control page for the specified
2518 * block number and control page level.
2519 */
2520 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2521 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2522 if (mp == NULL)
2523 return -EIO;
2524 dcp = (struct dmapctl *) mp->data;
2525
2526 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2527 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
2528 release_metapage(mp);
2529 return -EIO;
2530 }
2531
2532 /* determine the leaf number corresponding to the block and
2533 * the index within the dmap control tree.
2534 */
2535 leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2536 ti = leafno + le32_to_cpu(dcp->leafidx);
2537
2538 /* save the current leaf value and the current root level (i.e.
2539 * maximum l2 free string described by this dmapctl).
2540 */
2541 oldval = dcp->stree[ti];
2542 oldroot = dcp->stree[ROOT];
2543
2544 /* check if this is a control page update for an allocation.
2545 * if so, update the leaf to reflect the new leaf value using
2546 * dbSplit(); otherwise (deallocation), use dbJoin() to update
2547 * the leaf with the new value. in addition to updating the
2548 * leaf, dbSplit() will also split the binary buddy system of
2549 * the leaves, if required, and bubble new values within the
2550 * dmapctl tree, if required. similarly, dbJoin() will join
2551 * the binary buddy system of leaves and bubble new values up
2552 * the dmapctl tree as required by the new leaf value.
2553 */
2554 if (alloc) {
2555 /* check if we are in the middle of a binary buddy
2556 * system. this happens when we are performing the
2557 * first allocation out of an allocation group that
2558 * is part (not the first part) of a larger binary
2559 * buddy system. if we are in the middle, back split
2560 * the system prior to calling dbSplit() which assumes
2561 * that it is at the front of a binary buddy system.
2562 */
2563 if (oldval == NOFREE) {
2564 rc = dbBackSplit((dmtree_t *) dcp, leafno);
2565 if (rc)
2566 return rc;
2567 oldval = dcp->stree[ti];
2568 }
2569 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2570 } else {
2571 rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2572 if (rc)
2573 return rc;
2574 }
2575
2576 /* check if the root of the current dmap control page changed due
2577 * to the update and if the current dmap control page is not at
2578 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
2579 * root changed and this is not the top level), call this routine
2580 * again (recursion) for the next higher level of the mapping to
2581 * reflect the change in root for the current dmap control page.
2582 */
2583 if (dcp->stree[ROOT] != oldroot) {
2584 /* are we below the top level of the map. if so,
2585 * bubble the root up to the next higher level.
2586 */
2587 if (level < bmp->db_maxlevel) {
2588 /* bubble up the new root of this dmap control page to
2589 * the next level.
2590 */
2591 if ((rc =
2592 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2593 level + 1))) {
2594 /* something went wrong in bubbling up the new
2595 * root value, so backout the changes to the
2596 * current dmap control page.
2597 */
2598 if (alloc) {
2599 dbJoin((dmtree_t *) dcp, leafno,
2600 oldval);
2601 } else {
2602 /* the dbJoin() above might have
2603 * caused a larger binary buddy system
2604 * to form and we may now be in the
2605 * middle of it. if this is the case,
2606 * back split the buddies.
2607 */
2608 if (dcp->stree[ti] == NOFREE)
2609 dbBackSplit((dmtree_t *)
2610 dcp, leafno);
2611 dbSplit((dmtree_t *) dcp, leafno,
2612 dcp->budmin, oldval);
2613 }
2614
2615 /* release the buffer and return the error.
2616 */
2617 release_metapage(mp);
2618 return (rc);
2619 }
2620 } else {
2621 /* we're at the top level of the map. update
2622 * the bmap control page to reflect the size
2623 * of the maximum free buddy system.
2624 */
2625 assert(level == bmp->db_maxlevel);
2626 if (bmp->db_maxfreebud != oldroot) {
2627 jfs_error(bmp->db_ipbmap->i_sb,
2628 "the maximum free buddy is not the old root\n");
2629 }
2630 bmp->db_maxfreebud = dcp->stree[ROOT];
2631 }
2632 }
2633
2634 /* write the buffer.
2635 */
2636 write_metapage(mp);
2637
2638 return (0);
2639}
2640
2641
2642/*
2643 * NAME: dbSplit()
2644 *
2645 * FUNCTION: update the leaf of a dmtree with a new value, splitting
2646 * the leaf from the binary buddy system of the dmtree's
2647 * leaves, as required.
2648 *
2649 * PARAMETERS:
2650 * tp - pointer to the tree containing the leaf.
2651 * leafno - the number of the leaf to be updated.
2652 * splitsz - the size the binary buddy system starting at the leaf
2653 * must be split to, specified as the log2 number of blocks.
2654 * newval - the new value for the leaf.
2655 *
2656 * RETURN VALUES: none
2657 *
2658 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2659 */
2660static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2661{
2662 int budsz;
2663 int cursz;
2664 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2665
2666 /* check if the leaf needs to be split.
2667 */
2668 if (leaf[leafno] > tp->dmt_budmin) {
2669 /* the split occurs by cutting the buddy system in half
2670 * at the specified leaf until we reach the specified
2671 * size. pick up the starting split size (current size
2672 * - 1 in l2) and the corresponding buddy size.
2673 */
2674 cursz = leaf[leafno] - 1;
2675 budsz = BUDSIZE(cursz, tp->dmt_budmin);
2676
2677 /* split until we reach the specified size.
2678 */
2679 while (cursz >= splitsz) {
2680 /* update the buddy's leaf with its new value.
2681 */
2682 dbAdjTree(tp, leafno ^ budsz, cursz);
2683
2684 /* on to the next size and buddy.
2685 */
2686 cursz -= 1;
2687 budsz >>= 1;
2688 }
2689 }
2690
2691 /* adjust the dmap tree to reflect the specified leaf's new
2692 * value.
2693 */
2694 dbAdjTree(tp, leafno, newval);
2695}
2696
2697
2698/*
2699 * NAME: dbBackSplit()
2700 *
2701 * FUNCTION: back split the binary buddy system of dmtree leaves
2702 * that hold a specified leaf until the specified leaf
2703 * starts its own binary buddy system.
2704 *
2705 * the allocators typically perform allocations at the start
2706 * of binary buddy systems and dbSplit() is used to accomplish
2707 * any required splits. in some cases, however, allocation
2708 * may occur in the middle of a binary system and requires a
2709 * back split, with the split proceeding out from the middle of
2710 * the system (less efficient) rather than the start of the
2711 * system (more efficient). the cases in which a back split
2712 * is required are rare and are limited to the first allocation
2713 * within an allocation group which is a part (not first part)
2714 * of a larger binary buddy system and a few exception cases
2715 * in which a previous join operation must be backed out.
2716 *
2717 * PARAMETERS:
2718 * tp - pointer to the tree containing the leaf.
2719 * leafno - the number of the leaf to be updated.
2720 *
2721 * RETURN VALUES: none
2722 *
2723 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2724 */
2725static int dbBackSplit(dmtree_t * tp, int leafno)
2726{
2727 int budsz, bud, w, bsz, size;
2728 int cursz;
2729 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2730
2731 /* leaf should be part (not first part) of a binary
2732 * buddy system.
2733 */
2734 assert(leaf[leafno] == NOFREE);
2735
2736 /* the back split is accomplished by iteratively finding the leaf
2737 * that starts the buddy system that contains the specified leaf and
2738 * splitting that system in two. this iteration continues until
2739 * the specified leaf becomes the start of a buddy system.
2740 *
2741 * determine maximum possible l2 size for the specified leaf.
2742 */
2743 size =
2744 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2745 tp->dmt_budmin);
2746
2747 /* determine the number of leaves covered by this size. this
2748 * is the buddy size that we will start with as we search for
2749 * the buddy system that contains the specified leaf.
2750 */
2751 budsz = BUDSIZE(size, tp->dmt_budmin);
2752
2753 /* back split.
2754 */
2755 while (leaf[leafno] == NOFREE) {
2756 /* find the leftmost buddy leaf.
2757 */
2758 for (w = leafno, bsz = budsz;; bsz <<= 1,
2759 w = (w < bud) ? w : bud) {
2760 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2761 jfs_err("JFS: block map error in dbBackSplit");
2762 return -EIO;
2763 }
2764
2765 /* determine the buddy.
2766 */
2767 bud = w ^ bsz;
2768
2769 /* check if this buddy is the start of the system.
2770 */
2771 if (leaf[bud] != NOFREE) {
2772 /* split the leaf at the start of the
2773 * system in two.
2774 */
2775 cursz = leaf[bud] - 1;
2776 dbSplit(tp, bud, cursz, cursz);
2777 break;
2778 }
2779 }
2780 }
2781
2782 if (leaf[leafno] != size) {
2783 jfs_err("JFS: wrong leaf value in dbBackSplit");
2784 return -EIO;
2785 }
2786 return 0;
2787}
2788
2789
2790/*
2791 * NAME: dbJoin()
2792 *
2793 * FUNCTION: update the leaf of a dmtree with a new value, joining
2794 * the leaf with other leaves of the dmtree into a multi-leaf
2795 * binary buddy system, as required.
2796 *
2797 * PARAMETERS:
2798 * tp - pointer to the tree containing the leaf.
2799 * leafno - the number of the leaf to be updated.
2800 * newval - the new value for the leaf.
2801 *
2802 * RETURN VALUES: none
2803 */
2804static int dbJoin(dmtree_t * tp, int leafno, int newval)
2805{
2806 int budsz, buddy;
2807 s8 *leaf;
2808
2809 /* can the new leaf value require a join with other leaves ?
2810 */
2811 if (newval >= tp->dmt_budmin) {
2812 /* pickup a pointer to the leaves of the tree.
2813 */
2814 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2815
2816 /* try to join the specified leaf into a large binary
2817 * buddy system. the join proceeds by attempting to join
2818 * the specified leafno with its buddy (leaf) at new value.
2819 * if the join occurs, we attempt to join the left leaf
2820 * of the joined buddies with its buddy at new value + 1.
2821 * we continue to join until we find a buddy that cannot be
2822 * joined (does not have a value equal to the size of the
2823 * last join) or until all leaves have been joined into a
2824 * single system.
2825 *
2826 * get the buddy size (number of words covered) of
2827 * the new value.
2828 */
2829 budsz = BUDSIZE(newval, tp->dmt_budmin);
2830
2831 /* try to join.
2832 */
2833 while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2834 /* get the buddy leaf.
2835 */
2836 buddy = leafno ^ budsz;
2837
2838 /* if the leaf's new value is greater than its
2839 * buddy's value, we join no more.
2840 */
2841 if (newval > leaf[buddy])
2842 break;
2843
2844 /* It shouldn't be less */
2845 if (newval < leaf[buddy])
2846 return -EIO;
2847
2848 /* check which (leafno or buddy) is the left buddy.
2849 * the left buddy gets to claim the blocks resulting
2850 * from the join while the right gets to claim none.
2851 * the left buddy is also eligible to participate in
2852 * a join at the next higher level while the right
2853 * is not.
2854 *
2855 */
2856 if (leafno < buddy) {
2857 /* leafno is the left buddy.
2858 */
2859 dbAdjTree(tp, buddy, NOFREE);
2860 } else {
2861 /* buddy is the left buddy and becomes
2862 * leafno.
2863 */
2864 dbAdjTree(tp, leafno, NOFREE);
2865 leafno = buddy;
2866 }
2867
2868 /* on to try the next join.
2869 */
2870 newval += 1;
2871 budsz <<= 1;
2872 }
2873 }
2874
2875 /* update the leaf value.
2876 */
2877 dbAdjTree(tp, leafno, newval);
2878
2879 return 0;
2880}
2881
2882
2883/*
2884 * NAME: dbAdjTree()
2885 *
2886 * FUNCTION: update a leaf of a dmtree with a new value, adjusting
2887 * the dmtree, as required, to reflect the new leaf value.
2888 * the combination of any buddies must already be done before
2889 * this is called.
2890 *
2891 * PARAMETERS:
2892 * tp - pointer to the tree to be adjusted.
2893 * leafno - the number of the leaf to be updated.
2894 * newval - the new value for the leaf.
2895 *
2896 * RETURN VALUES: none
2897 */
2898static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2899{
2900 int lp, pp, k;
2901 int max;
2902
2903 /* pick up the index of the leaf for this leafno.
2904 */
2905 lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2906
2907 /* is the current value the same as the old value ? if so,
2908 * there is nothing to do.
2909 */
2910 if (tp->dmt_stree[lp] == newval)
2911 return;
2912
2913 /* set the new value.
2914 */
2915 tp->dmt_stree[lp] = newval;
2916
2917 /* bubble the new value up the tree as required.
2918 */
2919 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2920 /* get the index of the first leaf of the 4 leaf
2921 * group containing the specified leaf (leafno).
2922 */
2923 lp = ((lp - 1) & ~0x03) + 1;
2924
2925 /* get the index of the parent of this 4 leaf group.
2926 */
2927 pp = (lp - 1) >> 2;
2928
2929 /* determine the maximum of the 4 leaves.
2930 */
2931 max = TREEMAX(&tp->dmt_stree[lp]);
2932
2933 /* if the maximum of the 4 is the same as the
2934 * parent's value, we're done.
2935 */
2936 if (tp->dmt_stree[pp] == max)
2937 break;
2938
2939 /* parent gets new value.
2940 */
2941 tp->dmt_stree[pp] = max;
2942
2943 /* parent becomes leaf for next go-round.
2944 */
2945 lp = pp;
2946 }
2947}
2948
2949
2950/*
2951 * NAME: dbFindLeaf()
2952 *
2953 * FUNCTION: search a dmtree_t for sufficient free blocks, returning
2954 * the index of a leaf describing the free blocks if
2955 * sufficient free blocks are found.
2956 *
2957 * the search starts at the top of the dmtree_t tree and
2958 * proceeds down the tree to the leftmost leaf with sufficient
2959 * free space.
2960 *
2961 * PARAMETERS:
2962 * tp - pointer to the tree to be searched.
2963 * l2nb - log2 number of free blocks to search for.
2964 * leafidx - return pointer to be set to the index of the leaf
2965 * describing at least l2nb free blocks if sufficient
2966 * free blocks are found.
2967 *
2968 * RETURN VALUES:
2969 * 0 - success
2970 * -ENOSPC - insufficient free blocks.
2971 */
2972static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2973{
2974 int ti, n = 0, k, x = 0;
2975
2976 /* first check the root of the tree to see if there is
2977 * sufficient free space.
2978 */
2979 if (l2nb > tp->dmt_stree[ROOT])
2980 return -ENOSPC;
2981
2982 /* sufficient free space available. now search down the tree
2983 * starting at the next level for the leftmost leaf that
2984 * describes sufficient free space.
2985 */
2986 for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2987 k > 0; k--, ti = ((ti + n) << 2) + 1) {
2988 /* search the four nodes at this level, starting from
2989 * the left.
2990 */
2991 for (x = ti, n = 0; n < 4; n++) {
2992 /* sufficient free space found. move to the next
2993 * level (or quit if this is the last level).
2994 */
2995 if (l2nb <= tp->dmt_stree[x + n])
2996 break;
2997 }
2998
2999 /* better have found something since the higher
3000 * levels of the tree said it was here.
3001 */
3002 assert(n < 4);
3003 }
3004
3005 /* set the return to the leftmost leaf describing sufficient
3006 * free space.
3007 */
3008 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
3009
3010 return (0);
3011}
3012
3013
3014/*
3015 * NAME: dbFindBits()
3016 *
3017 * FUNCTION: find a specified number of binary buddy free bits within a
3018 * dmap bitmap word value.
3019 *
3020 * this routine searches the bitmap value for (1 << l2nb) free
3021 * bits at (1 << l2nb) alignments within the value.
3022 *
3023 * PARAMETERS:
3024 * word - dmap bitmap word value.
3025 * l2nb - number of free bits specified as a log2 number.
3026 *
3027 * RETURN VALUES:
3028 * starting bit number of free bits.
3029 */
3030static int dbFindBits(u32 word, int l2nb)
3031{
3032 int bitno, nb;
3033 u32 mask;
3034
3035 /* get the number of bits.
3036 */
3037 nb = 1 << l2nb;
3038 assert(nb <= DBWORD);
3039
3040 /* complement the word so we can use a mask (i.e. 0s represent
3041 * free bits) and compute the mask.
3042 */
3043 word = ~word;
3044 mask = ONES << (DBWORD - nb);
3045
3046 /* scan the word for nb free bits at nb alignments.
3047 */
3048 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
3049 if ((mask & word) == mask)
3050 break;
3051 }
3052
3053 ASSERT(bitno < 32);
3054
3055 /* return the bit number.
3056 */
3057 return (bitno);
3058}
3059
3060
3061/*
3062 * NAME: dbMaxBud(u8 *cp)
3063 *
3064 * FUNCTION: determine the largest binary buddy string of free
3065 * bits within 32-bits of the map.
3066 *
3067 * PARAMETERS:
3068 * cp - pointer to the 32-bit value.
3069 *
3070 * RETURN VALUES:
3071 * largest binary buddy of free bits within a dmap word.
3072 */
3073static int dbMaxBud(u8 * cp)
3074{
3075 signed char tmp1, tmp2;
3076
3077 /* check if the wmap word is all free. if so, the
3078 * free buddy size is BUDMIN.
3079 */
3080 if (*((uint *) cp) == 0)
3081 return (BUDMIN);
3082
3083 /* check if the wmap word is half free. if so, the
3084 * free buddy size is BUDMIN-1.
3085 */
3086 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
3087 return (BUDMIN - 1);
3088
3089 /* not all free or half free. determine the free buddy
3090 * size thru table lookup using quarters of the wmap word.
3091 */
3092 tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
3093 tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
3094 return (max(tmp1, tmp2));
3095}
3096
3097
3098/*
3099 * NAME: cnttz(uint word)
3100 *
3101 * FUNCTION: determine the number of trailing zeros within a 32-bit
3102 * value.
3103 *
3104 * PARAMETERS:
3105 * value - 32-bit value to be examined.
3106 *
3107 * RETURN VALUES:
3108 * count of trailing zeros
3109 */
3110static int cnttz(u32 word)
3111{
3112 int n;
3113
3114 for (n = 0; n < 32; n++, word >>= 1) {
3115 if (word & 0x01)
3116 break;
3117 }
3118
3119 return (n);
3120}
3121
3122
3123/*
3124 * NAME: cntlz(u32 value)
3125 *
3126 * FUNCTION: determine the number of leading zeros within a 32-bit
3127 * value.
3128 *
3129 * PARAMETERS:
3130 * value - 32-bit value to be examined.
3131 *
3132 * RETURN VALUES:
3133 * count of leading zeros
3134 */
3135static int cntlz(u32 value)
3136{
3137 int n;
3138
3139 for (n = 0; n < 32; n++, value <<= 1) {
3140 if (value & HIGHORDER)
3141 break;
3142 }
3143 return (n);
3144}
3145
3146
3147/*
3148 * NAME: blkstol2(s64 nb)
3149 *
3150 * FUNCTION: convert a block count to its log2 value. if the block
3151 * count is not a l2 multiple, it is rounded up to the next
3152 * larger l2 multiple.
3153 *
3154 * PARAMETERS:
3155 * nb - number of blocks
3156 *
3157 * RETURN VALUES:
3158 * log2 number of blocks
3159 */
3160static int blkstol2(s64 nb)
3161{
3162 int l2nb;
3163 s64 mask; /* meant to be signed */
3164
3165 mask = (s64) 1 << (64 - 1);
3166
3167 /* count the leading bits.
3168 */
3169 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3170 /* leading bit found.
3171 */
3172 if (nb & mask) {
3173 /* determine the l2 value.
3174 */
3175 l2nb = (64 - 1) - l2nb;
3176
3177 /* check if we need to round up.
3178 */
3179 if (~mask & nb)
3180 l2nb++;
3181
3182 return (l2nb);
3183 }
3184 }
3185 assert(0);
3186 return 0; /* fix compiler warning */
3187}
3188
3189
3190/*
3191 * NAME: dbAllocBottomUp()
3192 *
3193 * FUNCTION: alloc the specified block range from the working block
3194 * allocation map.
3195 *
3196 * the blocks will be alloc from the working map one dmap
3197 * at a time.
3198 *
3199 * PARAMETERS:
3200 * ip - pointer to in-core inode;
3201 * blkno - starting block number to be freed.
3202 * nblocks - number of blocks to be freed.
3203 *
3204 * RETURN VALUES:
3205 * 0 - success
3206 * -EIO - i/o error
3207 */
3208int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3209{
3210 struct metapage *mp;
3211 struct dmap *dp;
3212 int nb, rc;
3213 s64 lblkno, rem;
3214 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3215 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3216
3217 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3218
3219 /* block to be allocated better be within the mapsize. */
3220 ASSERT(nblocks <= bmp->db_mapsize - blkno);
3221
3222 /*
3223 * allocate the blocks a dmap at a time.
3224 */
3225 mp = NULL;
3226 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3227 /* release previous dmap if any */
3228 if (mp) {
3229 write_metapage(mp);
3230 }
3231
3232 /* get the buffer for the current dmap. */
3233 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3234 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3235 if (mp == NULL) {
3236 IREAD_UNLOCK(ipbmap);
3237 return -EIO;
3238 }
3239 dp = (struct dmap *) mp->data;
3240
3241 /* determine the number of blocks to be allocated from
3242 * this dmap.
3243 */
3244 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3245
3246 /* allocate the blocks. */
3247 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3248 release_metapage(mp);
3249 IREAD_UNLOCK(ipbmap);
3250 return (rc);
3251 }
3252 }
3253
3254 /* write the last buffer. */
3255 write_metapage(mp);
3256
3257 IREAD_UNLOCK(ipbmap);
3258
3259 return (0);
3260}
3261
3262
3263static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3264 int nblocks)
3265{
3266 int rc;
3267 int dbitno, word, rembits, nb, nwords, wbitno, agno;
3268 s8 oldroot;
3269 struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3270
3271 /* save the current value of the root (i.e. maximum free string)
3272 * of the dmap tree.
3273 */
3274 oldroot = tp->stree[ROOT];
3275
3276 /* determine the bit number and word within the dmap of the
3277 * starting block.
3278 */
3279 dbitno = blkno & (BPERDMAP - 1);
3280 word = dbitno >> L2DBWORD;
3281
3282 /* block range better be within the dmap */
3283 assert(dbitno + nblocks <= BPERDMAP);
3284
3285 /* allocate the bits of the dmap's words corresponding to the block
3286 * range. not all bits of the first and last words may be contained
3287 * within the block range. if this is the case, we'll work against
3288 * those words (i.e. partial first and/or last) on an individual basis
3289 * (a single pass), allocating the bits of interest by hand and
3290 * updating the leaf corresponding to the dmap word. a single pass
3291 * will be used for all dmap words fully contained within the
3292 * specified range. within this pass, the bits of all fully contained
3293 * dmap words will be marked as free in a single shot and the leaves
3294 * will be updated. a single leaf may describe the free space of
3295 * multiple dmap words, so we may update only a subset of the actual
3296 * leaves corresponding to the dmap words of the block range.
3297 */
3298 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3299 /* determine the bit number within the word and
3300 * the number of bits within the word.
3301 */
3302 wbitno = dbitno & (DBWORD - 1);
3303 nb = min(rembits, DBWORD - wbitno);
3304
3305 /* check if only part of a word is to be allocated.
3306 */
3307 if (nb < DBWORD) {
3308 /* allocate (set to 1) the appropriate bits within
3309 * this dmap word.
3310 */
3311 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3312 >> wbitno);
3313
3314 word++;
3315 } else {
3316 /* one or more dmap words are fully contained
3317 * within the block range. determine how many
3318 * words and allocate (set to 1) the bits of these
3319 * words.
3320 */
3321 nwords = rembits >> L2DBWORD;
3322 memset(&dp->wmap[word], (int) ONES, nwords * 4);
3323
3324 /* determine how many bits */
3325 nb = nwords << L2DBWORD;
3326 word += nwords;
3327 }
3328 }
3329
3330 /* update the free count for this dmap */
3331 le32_add_cpu(&dp->nfree, -nblocks);
3332
3333 /* reconstruct summary tree */
3334 dbInitDmapTree(dp);
3335
3336 BMAP_LOCK(bmp);
3337
3338 /* if this allocation group is completely free,
3339 * update the highest active allocation group number
3340 * if this allocation group is the new max.
3341 */
3342 agno = blkno >> bmp->db_agl2size;
3343 if (agno > bmp->db_maxag)
3344 bmp->db_maxag = agno;
3345
3346 /* update the free count for the allocation group and map */
3347 bmp->db_agfree[agno] -= nblocks;
3348 bmp->db_nfree -= nblocks;
3349
3350 BMAP_UNLOCK(bmp);
3351
3352 /* if the root has not changed, done. */
3353 if (tp->stree[ROOT] == oldroot)
3354 return (0);
3355
3356 /* root changed. bubble the change up to the dmap control pages.
3357 * if the adjustment of the upper level control pages fails,
3358 * backout the bit allocation (thus making everything consistent).
3359 */
3360 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3361 dbFreeBits(bmp, dp, blkno, nblocks);
3362
3363 return (rc);
3364}
3365
3366
3367/*
3368 * NAME: dbExtendFS()
3369 *
3370 * FUNCTION: extend bmap from blkno for nblocks;
3371 * dbExtendFS() updates bmap ready for dbAllocBottomUp();
3372 *
3373 * L2
3374 * |
3375 * L1---------------------------------L1
3376 * | |
3377 * L0---------L0---------L0 L0---------L0---------L0
3378 * | | | | | |
3379 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
3380 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3381 *
3382 * <---old---><----------------------------extend----------------------->
3383 */
3384int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3385{
3386 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3387 int nbperpage = sbi->nbperpage;
3388 int i, i0 = true, j, j0 = true, k, n;
3389 s64 newsize;
3390 s64 p;
3391 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3392 struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3393 struct dmap *dp;
3394 s8 *l0leaf, *l1leaf, *l2leaf;
3395 struct bmap *bmp = sbi->bmap;
3396 int agno, l2agsize, oldl2agsize;
3397 s64 ag_rem;
3398
3399 newsize = blkno + nblocks;
3400
3401 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3402 (long long) blkno, (long long) nblocks, (long long) newsize);
3403
3404 /*
3405 * initialize bmap control page.
3406 *
3407 * all the data in bmap control page should exclude
3408 * the mkfs hidden dmap page.
3409 */
3410
3411 /* update mapsize */
3412 bmp->db_mapsize = newsize;
3413 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3414
3415 /* compute new AG size */
3416 l2agsize = dbGetL2AGSize(newsize);
3417 oldl2agsize = bmp->db_agl2size;
3418
3419 bmp->db_agl2size = l2agsize;
3420 bmp->db_agsize = 1 << l2agsize;
3421
3422 /* compute new number of AG */
3423 agno = bmp->db_numag;
3424 bmp->db_numag = newsize >> l2agsize;
3425 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3426
3427 /*
3428 * reconfigure db_agfree[]
3429 * from old AG configuration to new AG configuration;
3430 *
3431 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3432 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3433 * note: new AG size = old AG size * (2**x).
3434 */
3435 if (l2agsize == oldl2agsize)
3436 goto extend;
3437 k = 1 << (l2agsize - oldl2agsize);
3438 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
3439 for (i = 0, n = 0; i < agno; n++) {
3440 bmp->db_agfree[n] = 0; /* init collection point */
3441
3442 /* coalesce contiguous k AGs; */
3443 for (j = 0; j < k && i < agno; j++, i++) {
3444 /* merge AGi to AGn */
3445 bmp->db_agfree[n] += bmp->db_agfree[i];
3446 }
3447 }
3448 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
3449
3450 for (; n < MAXAG; n++)
3451 bmp->db_agfree[n] = 0;
3452
3453 /*
3454 * update highest active ag number
3455 */
3456
3457 bmp->db_maxag = bmp->db_maxag / k;
3458
3459 /*
3460 * extend bmap
3461 *
3462 * update bit maps and corresponding level control pages;
3463 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3464 */
3465 extend:
3466 /* get L2 page */
3467 p = BMAPBLKNO + nbperpage; /* L2 page */
3468 l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3469 if (!l2mp) {
3470 jfs_error(ipbmap->i_sb, "L2 page could not be read\n");
3471 return -EIO;
3472 }
3473 l2dcp = (struct dmapctl *) l2mp->data;
3474
3475 /* compute start L1 */
3476 k = blkno >> L2MAXL1SIZE;
3477 l2leaf = l2dcp->stree + CTLLEAFIND + k;
3478 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
3479
3480 /*
3481 * extend each L1 in L2
3482 */
3483 for (; k < LPERCTL; k++, p += nbperpage) {
3484 /* get L1 page */
3485 if (j0) {
3486 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3487 l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3488 if (l1mp == NULL)
3489 goto errout;
3490 l1dcp = (struct dmapctl *) l1mp->data;
3491
3492 /* compute start L0 */
3493 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3494 l1leaf = l1dcp->stree + CTLLEAFIND + j;
3495 p = BLKTOL0(blkno, sbi->l2nbperpage);
3496 j0 = false;
3497 } else {
3498 /* assign/init L1 page */
3499 l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3500 if (l1mp == NULL)
3501 goto errout;
3502
3503 l1dcp = (struct dmapctl *) l1mp->data;
3504
3505 /* compute start L0 */
3506 j = 0;
3507 l1leaf = l1dcp->stree + CTLLEAFIND;
3508 p += nbperpage; /* 1st L0 of L1.k */
3509 }
3510
3511 /*
3512 * extend each L0 in L1
3513 */
3514 for (; j < LPERCTL; j++) {
3515 /* get L0 page */
3516 if (i0) {
3517 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3518
3519 l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3520 if (l0mp == NULL)
3521 goto errout;
3522 l0dcp = (struct dmapctl *) l0mp->data;
3523
3524 /* compute start dmap */
3525 i = (blkno & (MAXL0SIZE - 1)) >>
3526 L2BPERDMAP;
3527 l0leaf = l0dcp->stree + CTLLEAFIND + i;
3528 p = BLKTODMAP(blkno,
3529 sbi->l2nbperpage);
3530 i0 = false;
3531 } else {
3532 /* assign/init L0 page */
3533 l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3534 if (l0mp == NULL)
3535 goto errout;
3536
3537 l0dcp = (struct dmapctl *) l0mp->data;
3538
3539 /* compute start dmap */
3540 i = 0;
3541 l0leaf = l0dcp->stree + CTLLEAFIND;
3542 p += nbperpage; /* 1st dmap of L0.j */
3543 }
3544
3545 /*
3546 * extend each dmap in L0
3547 */
3548 for (; i < LPERCTL; i++) {
3549 /*
3550 * reconstruct the dmap page, and
3551 * initialize corresponding parent L0 leaf
3552 */
3553 if ((n = blkno & (BPERDMAP - 1))) {
3554 /* read in dmap page: */
3555 mp = read_metapage(ipbmap, p,
3556 PSIZE, 0);
3557 if (mp == NULL)
3558 goto errout;
3559 n = min(nblocks, (s64)BPERDMAP - n);
3560 } else {
3561 /* assign/init dmap page */
3562 mp = read_metapage(ipbmap, p,
3563 PSIZE, 0);
3564 if (mp == NULL)
3565 goto errout;
3566
3567 n = min_t(s64, nblocks, BPERDMAP);
3568 }
3569
3570 dp = (struct dmap *) mp->data;
3571 *l0leaf = dbInitDmap(dp, blkno, n);
3572
3573 bmp->db_nfree += n;
3574 agno = le64_to_cpu(dp->start) >> l2agsize;
3575 bmp->db_agfree[agno] += n;
3576
3577 write_metapage(mp);
3578
3579 l0leaf++;
3580 p += nbperpage;
3581
3582 blkno += n;
3583 nblocks -= n;
3584 if (nblocks == 0)
3585 break;
3586 } /* for each dmap in a L0 */
3587
3588 /*
3589 * build current L0 page from its leaves, and
3590 * initialize corresponding parent L1 leaf
3591 */
3592 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3593 write_metapage(l0mp);
3594 l0mp = NULL;
3595
3596 if (nblocks)
3597 l1leaf++; /* continue for next L0 */
3598 else {
3599 /* more than 1 L0 ? */
3600 if (j > 0)
3601 break; /* build L1 page */
3602 else {
3603 /* summarize in global bmap page */
3604 bmp->db_maxfreebud = *l1leaf;
3605 release_metapage(l1mp);
3606 release_metapage(l2mp);
3607 goto finalize;
3608 }
3609 }
3610 } /* for each L0 in a L1 */
3611
3612 /*
3613 * build current L1 page from its leaves, and
3614 * initialize corresponding parent L2 leaf
3615 */
3616 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3617 write_metapage(l1mp);
3618 l1mp = NULL;
3619
3620 if (nblocks)
3621 l2leaf++; /* continue for next L1 */
3622 else {
3623 /* more than 1 L1 ? */
3624 if (k > 0)
3625 break; /* build L2 page */
3626 else {
3627 /* summarize in global bmap page */
3628 bmp->db_maxfreebud = *l2leaf;
3629 release_metapage(l2mp);
3630 goto finalize;
3631 }
3632 }
3633 } /* for each L1 in a L2 */
3634
3635 jfs_error(ipbmap->i_sb, "function has not returned as expected\n");
3636errout:
3637 if (l0mp)
3638 release_metapage(l0mp);
3639 if (l1mp)
3640 release_metapage(l1mp);
3641 release_metapage(l2mp);
3642 return -EIO;
3643
3644 /*
3645 * finalize bmap control page
3646 */
3647finalize:
3648
3649 return 0;
3650}
3651
3652
3653/*
3654 * dbFinalizeBmap()
3655 */
3656void dbFinalizeBmap(struct inode *ipbmap)
3657{
3658 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3659 int actags, inactags, l2nl;
3660 s64 ag_rem, actfree, inactfree, avgfree;
3661 int i, n;
3662
3663 /*
3664 * finalize bmap control page
3665 */
3666//finalize:
3667 /*
3668 * compute db_agpref: preferred ag to allocate from
3669 * (the leftmost ag with average free space in it);
3670 */
3671//agpref:
3672 /* get the number of active ags and inacitve ags */
3673 actags = bmp->db_maxag + 1;
3674 inactags = bmp->db_numag - actags;
3675 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
3676
3677 /* determine how many blocks are in the inactive allocation
3678 * groups. in doing this, we must account for the fact that
3679 * the rightmost group might be a partial group (i.e. file
3680 * system size is not a multiple of the group size).
3681 */
3682 inactfree = (inactags && ag_rem) ?
3683 ((inactags - 1) << bmp->db_agl2size) + ag_rem
3684 : inactags << bmp->db_agl2size;
3685
3686 /* determine how many free blocks are in the active
3687 * allocation groups plus the average number of free blocks
3688 * within the active ags.
3689 */
3690 actfree = bmp->db_nfree - inactfree;
3691 avgfree = (u32) actfree / (u32) actags;
3692
3693 /* if the preferred allocation group has not average free space.
3694 * re-establish the preferred group as the leftmost
3695 * group with average free space.
3696 */
3697 if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3698 for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3699 bmp->db_agpref++) {
3700 if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3701 break;
3702 }
3703 if (bmp->db_agpref >= bmp->db_numag) {
3704 jfs_error(ipbmap->i_sb,
3705 "cannot find ag with average freespace\n");
3706 }
3707 }
3708
3709 /*
3710 * compute db_aglevel, db_agheight, db_width, db_agstart:
3711 * an ag is covered in aglevel dmapctl summary tree,
3712 * at agheight level height (from leaf) with agwidth number of nodes
3713 * each, which starts at agstart index node of the smmary tree node
3714 * array;
3715 */
3716 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3717 l2nl =
3718 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3719 bmp->db_agheight = l2nl >> 1;
3720 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3721 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3722 i--) {
3723 bmp->db_agstart += n;
3724 n <<= 2;
3725 }
3726
3727}
3728
3729
3730/*
3731 * NAME: dbInitDmap()/ujfs_idmap_page()
3732 *
3733 * FUNCTION: initialize working/persistent bitmap of the dmap page
3734 * for the specified number of blocks:
3735 *
3736 * at entry, the bitmaps had been initialized as free (ZEROS);
3737 * The number of blocks will only account for the actually
3738 * existing blocks. Blocks which don't actually exist in
3739 * the aggregate will be marked as allocated (ONES);
3740 *
3741 * PARAMETERS:
3742 * dp - pointer to page of map
3743 * nblocks - number of blocks this page
3744 *
3745 * RETURNS: NONE
3746 */
3747static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3748{
3749 int blkno, w, b, r, nw, nb, i;
3750
3751 /* starting block number within the dmap */
3752 blkno = Blkno & (BPERDMAP - 1);
3753
3754 if (blkno == 0) {
3755 dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3756 dp->start = cpu_to_le64(Blkno);
3757
3758 if (nblocks == BPERDMAP) {
3759 memset(&dp->wmap[0], 0, LPERDMAP * 4);
3760 memset(&dp->pmap[0], 0, LPERDMAP * 4);
3761 goto initTree;
3762 }
3763 } else {
3764 le32_add_cpu(&dp->nblocks, nblocks);
3765 le32_add_cpu(&dp->nfree, nblocks);
3766 }
3767
3768 /* word number containing start block number */
3769 w = blkno >> L2DBWORD;
3770
3771 /*
3772 * free the bits corresponding to the block range (ZEROS):
3773 * note: not all bits of the first and last words may be contained
3774 * within the block range.
3775 */
3776 for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3777 /* number of bits preceding range to be freed in the word */
3778 b = blkno & (DBWORD - 1);
3779 /* number of bits to free in the word */
3780 nb = min(r, DBWORD - b);
3781
3782 /* is partial word to be freed ? */
3783 if (nb < DBWORD) {
3784 /* free (set to 0) from the bitmap word */
3785 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3786 >> b));
3787 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3788 >> b));
3789
3790 /* skip the word freed */
3791 w++;
3792 } else {
3793 /* free (set to 0) contiguous bitmap words */
3794 nw = r >> L2DBWORD;
3795 memset(&dp->wmap[w], 0, nw * 4);
3796 memset(&dp->pmap[w], 0, nw * 4);
3797
3798 /* skip the words freed */
3799 nb = nw << L2DBWORD;
3800 w += nw;
3801 }
3802 }
3803
3804 /*
3805 * mark bits following the range to be freed (non-existing
3806 * blocks) as allocated (ONES)
3807 */
3808
3809 if (blkno == BPERDMAP)
3810 goto initTree;
3811
3812 /* the first word beyond the end of existing blocks */
3813 w = blkno >> L2DBWORD;
3814
3815 /* does nblocks fall on a 32-bit boundary ? */
3816 b = blkno & (DBWORD - 1);
3817 if (b) {
3818 /* mark a partial word allocated */
3819 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3820 w++;
3821 }
3822
3823 /* set the rest of the words in the page to allocated (ONES) */
3824 for (i = w; i < LPERDMAP; i++)
3825 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3826
3827 /*
3828 * init tree
3829 */
3830 initTree:
3831 return (dbInitDmapTree(dp));
3832}
3833
3834
3835/*
3836 * NAME: dbInitDmapTree()/ujfs_complete_dmap()
3837 *
3838 * FUNCTION: initialize summary tree of the specified dmap:
3839 *
3840 * at entry, bitmap of the dmap has been initialized;
3841 *
3842 * PARAMETERS:
3843 * dp - dmap to complete
3844 * blkno - starting block number for this dmap
3845 * treemax - will be filled in with max free for this dmap
3846 *
3847 * RETURNS: max free string at the root of the tree
3848 */
3849static int dbInitDmapTree(struct dmap * dp)
3850{
3851 struct dmaptree *tp;
3852 s8 *cp;
3853 int i;
3854
3855 /* init fixed info of tree */
3856 tp = &dp->tree;
3857 tp->nleafs = cpu_to_le32(LPERDMAP);
3858 tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3859 tp->leafidx = cpu_to_le32(LEAFIND);
3860 tp->height = cpu_to_le32(4);
3861 tp->budmin = BUDMIN;
3862
3863 /* init each leaf from corresponding wmap word:
3864 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3865 * bitmap word are allocated.
3866 */
3867 cp = tp->stree + le32_to_cpu(tp->leafidx);
3868 for (i = 0; i < LPERDMAP; i++)
3869 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3870
3871 /* build the dmap's binary buddy summary tree */
3872 return (dbInitTree(tp));
3873}
3874
3875
3876/*
3877 * NAME: dbInitTree()/ujfs_adjtree()
3878 *
3879 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
3880 *
3881 * at entry, the leaves of the tree has been initialized
3882 * from corresponding bitmap word or root of summary tree
3883 * of the child control page;
3884 * configure binary buddy system at the leaf level, then
3885 * bubble up the values of the leaf nodes up the tree.
3886 *
3887 * PARAMETERS:
3888 * cp - Pointer to the root of the tree
3889 * l2leaves- Number of leaf nodes as a power of 2
3890 * l2min - Number of blocks that can be covered by a leaf
3891 * as a power of 2
3892 *
3893 * RETURNS: max free string at the root of the tree
3894 */
3895static int dbInitTree(struct dmaptree * dtp)
3896{
3897 int l2max, l2free, bsize, nextb, i;
3898 int child, parent, nparent;
3899 s8 *tp, *cp, *cp1;
3900
3901 tp = dtp->stree;
3902
3903 /* Determine the maximum free string possible for the leaves */
3904 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3905
3906 /*
3907 * configure the leaf levevl into binary buddy system
3908 *
3909 * Try to combine buddies starting with a buddy size of 1
3910 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3911 * can be combined if both buddies have a maximum free of l2min;
3912 * the combination will result in the left-most buddy leaf having
3913 * a maximum free of l2min+1.
3914 * After processing all buddies for a given size, process buddies
3915 * at the next higher buddy size (i.e. current size * 2) and
3916 * the next maximum free (current free + 1).
3917 * This continues until the maximum possible buddy combination
3918 * yields maximum free.
3919 */
3920 for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3921 l2free++, bsize = nextb) {
3922 /* get next buddy size == current buddy pair size */
3923 nextb = bsize << 1;
3924
3925 /* scan each adjacent buddy pair at current buddy size */
3926 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3927 i < le32_to_cpu(dtp->nleafs);
3928 i += nextb, cp += nextb) {
3929 /* coalesce if both adjacent buddies are max free */
3930 if (*cp == l2free && *(cp + bsize) == l2free) {
3931 *cp = l2free + 1; /* left take right */
3932 *(cp + bsize) = -1; /* right give left */
3933 }
3934 }
3935 }
3936
3937 /*
3938 * bubble summary information of leaves up the tree.
3939 *
3940 * Starting at the leaf node level, the four nodes described by
3941 * the higher level parent node are compared for a maximum free and
3942 * this maximum becomes the value of the parent node.
3943 * when all lower level nodes are processed in this fashion then
3944 * move up to the next level (parent becomes a lower level node) and
3945 * continue the process for that level.
3946 */
3947 for (child = le32_to_cpu(dtp->leafidx),
3948 nparent = le32_to_cpu(dtp->nleafs) >> 2;
3949 nparent > 0; nparent >>= 2, child = parent) {
3950 /* get index of 1st node of parent level */
3951 parent = (child - 1) >> 2;
3952
3953 /* set the value of the parent node as the maximum
3954 * of the four nodes of the current level.
3955 */
3956 for (i = 0, cp = tp + child, cp1 = tp + parent;
3957 i < nparent; i++, cp += 4, cp1++)
3958 *cp1 = TREEMAX(cp);
3959 }
3960
3961 return (*tp);
3962}
3963
3964
3965/*
3966 * dbInitDmapCtl()
3967 *
3968 * function: initialize dmapctl page
3969 */
3970static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3971{ /* start leaf index not covered by range */
3972 s8 *cp;
3973
3974 dcp->nleafs = cpu_to_le32(LPERCTL);
3975 dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3976 dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3977 dcp->height = cpu_to_le32(5);
3978 dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3979
3980 /*
3981 * initialize the leaves of current level that were not covered
3982 * by the specified input block range (i.e. the leaves have no
3983 * low level dmapctl or dmap).
3984 */
3985 cp = &dcp->stree[CTLLEAFIND + i];
3986 for (; i < LPERCTL; i++)
3987 *cp++ = NOFREE;
3988
3989 /* build the dmap's binary buddy summary tree */
3990 return (dbInitTree((struct dmaptree *) dcp));
3991}
3992
3993
3994/*
3995 * NAME: dbGetL2AGSize()/ujfs_getagl2size()
3996 *
3997 * FUNCTION: Determine log2(allocation group size) from aggregate size
3998 *
3999 * PARAMETERS:
4000 * nblocks - Number of blocks in aggregate
4001 *
4002 * RETURNS: log2(allocation group size) in aggregate blocks
4003 */
4004static int dbGetL2AGSize(s64 nblocks)
4005{
4006 s64 sz;
4007 s64 m;
4008 int l2sz;
4009
4010 if (nblocks < BPERDMAP * MAXAG)
4011 return (L2BPERDMAP);
4012
4013 /* round up aggregate size to power of 2 */
4014 m = ((u64) 1 << (64 - 1));
4015 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
4016 if (m & nblocks)
4017 break;
4018 }
4019
4020 sz = (s64) 1 << l2sz;
4021 if (sz < nblocks)
4022 l2sz += 1;
4023
4024 /* agsize = roundupSize/max_number_of_ag */
4025 return (l2sz - L2MAXAG);
4026}
4027
4028
4029/*
4030 * NAME: dbMapFileSizeToMapSize()
4031 *
4032 * FUNCTION: compute number of blocks the block allocation map file
4033 * can cover from the map file size;
4034 *
4035 * RETURNS: Number of blocks which can be covered by this block map file;
4036 */
4037
4038/*
4039 * maximum number of map pages at each level including control pages
4040 */
4041#define MAXL0PAGES (1 + LPERCTL)
4042#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
4043#define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
4044
4045/*
4046 * convert number of map pages to the zero origin top dmapctl level
4047 */
4048#define BMAPPGTOLEV(npages) \
4049 (((npages) <= 3 + MAXL0PAGES) ? 0 : \
4050 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
4051
4052s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
4053{
4054 struct super_block *sb = ipbmap->i_sb;
4055 s64 nblocks;
4056 s64 npages, ndmaps;
4057 int level, i;
4058 int complete, factor;
4059
4060 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
4061 npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
4062 level = BMAPPGTOLEV(npages);
4063
4064 /* At each level, accumulate the number of dmap pages covered by
4065 * the number of full child levels below it;
4066 * repeat for the last incomplete child level.
4067 */
4068 ndmaps = 0;
4069 npages--; /* skip the first global control page */
4070 /* skip higher level control pages above top level covered by map */
4071 npages -= (2 - level);
4072 npages--; /* skip top level's control page */
4073 for (i = level; i >= 0; i--) {
4074 factor =
4075 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
4076 complete = (u32) npages / factor;
4077 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
4078 ((i == 1) ? LPERCTL : 1));
4079
4080 /* pages in last/incomplete child */
4081 npages = (u32) npages % factor;
4082 /* skip incomplete child's level control page */
4083 npages--;
4084 }
4085
4086 /* convert the number of dmaps into the number of blocks
4087 * which can be covered by the dmaps;
4088 */
4089 nblocks = ndmaps << L2BPERDMAP;
4090
4091 return (nblocks);
4092}
1/*
2 * Copyright (C) International Business Machines Corp., 2000-2004
3 *
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.
8 *
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.
13 *
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
17 */
18
19#include <linux/fs.h>
20#include <linux/slab.h>
21#include "jfs_incore.h"
22#include "jfs_superblock.h"
23#include "jfs_dmap.h"
24#include "jfs_imap.h"
25#include "jfs_lock.h"
26#include "jfs_metapage.h"
27#include "jfs_debug.h"
28
29/*
30 * SERIALIZATION of the Block Allocation Map.
31 *
32 * the working state of the block allocation map is accessed in
33 * two directions:
34 *
35 * 1) allocation and free requests that start at the dmap
36 * level and move up through the dmap control pages (i.e.
37 * the vast majority of requests).
38 *
39 * 2) allocation requests that start at dmap control page
40 * level and work down towards the dmaps.
41 *
42 * the serialization scheme used here is as follows.
43 *
44 * requests which start at the bottom are serialized against each
45 * other through buffers and each requests holds onto its buffers
46 * as it works it way up from a single dmap to the required level
47 * of dmap control page.
48 * requests that start at the top are serialized against each other
49 * and request that start from the bottom by the multiple read/single
50 * write inode lock of the bmap inode. requests starting at the top
51 * take this lock in write mode while request starting at the bottom
52 * take the lock in read mode. a single top-down request may proceed
53 * exclusively while multiple bottoms-up requests may proceed
54 * simultaneously (under the protection of busy buffers).
55 *
56 * in addition to information found in dmaps and dmap control pages,
57 * the working state of the block allocation map also includes read/
58 * write information maintained in the bmap descriptor (i.e. total
59 * free block count, allocation group level free block counts).
60 * a single exclusive lock (BMAP_LOCK) is used to guard this information
61 * in the face of multiple-bottoms up requests.
62 * (lock ordering: IREAD_LOCK, BMAP_LOCK);
63 *
64 * accesses to the persistent state of the block allocation map (limited
65 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
66 */
67
68#define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
69#define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
70#define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
71
72/*
73 * forward references
74 */
75static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
76 int nblocks);
77static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
78static int dbBackSplit(dmtree_t * tp, int leafno);
79static int dbJoin(dmtree_t * tp, int leafno, int newval);
80static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
81static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
82 int level);
83static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
84static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
85 int nblocks);
86static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
87 int nblocks,
88 int l2nb, s64 * results);
89static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
90 int nblocks);
91static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
92 int l2nb,
93 s64 * results);
94static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
95 s64 * results);
96static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
97 s64 * results);
98static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
99static int dbFindBits(u32 word, int l2nb);
100static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
101static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
102static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
103 int nblocks);
104static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
105 int nblocks);
106static int dbMaxBud(u8 * cp);
107s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
108static int blkstol2(s64 nb);
109
110static int cntlz(u32 value);
111static int cnttz(u32 word);
112
113static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
114 int nblocks);
115static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
116static int dbInitDmapTree(struct dmap * dp);
117static int dbInitTree(struct dmaptree * dtp);
118static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
119static int dbGetL2AGSize(s64 nblocks);
120
121/*
122 * buddy table
123 *
124 * table used for determining buddy sizes within characters of
125 * dmap bitmap words. the characters themselves serve as indexes
126 * into the table, with the table elements yielding the maximum
127 * binary buddy of free bits within the character.
128 */
129static const s8 budtab[256] = {
130 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
138 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
142 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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, 0,
145 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
146};
147
148
149/*
150 * NAME: dbMount()
151 *
152 * FUNCTION: initializate the block allocation map.
153 *
154 * memory is allocated for the in-core bmap descriptor and
155 * the in-core descriptor is initialized from disk.
156 *
157 * PARAMETERS:
158 * ipbmap - pointer to in-core inode for the block map.
159 *
160 * RETURN VALUES:
161 * 0 - success
162 * -ENOMEM - insufficient memory
163 * -EIO - i/o error
164 */
165int dbMount(struct inode *ipbmap)
166{
167 struct bmap *bmp;
168 struct dbmap_disk *dbmp_le;
169 struct metapage *mp;
170 int i;
171
172 /*
173 * allocate/initialize the in-memory bmap descriptor
174 */
175 /* allocate memory for the in-memory bmap descriptor */
176 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
177 if (bmp == NULL)
178 return -ENOMEM;
179
180 /* read the on-disk bmap descriptor. */
181 mp = read_metapage(ipbmap,
182 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
183 PSIZE, 0);
184 if (mp == NULL) {
185 kfree(bmp);
186 return -EIO;
187 }
188
189 /* copy the on-disk bmap descriptor to its in-memory version. */
190 dbmp_le = (struct dbmap_disk *) mp->data;
191 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
192 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
193 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
194 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
195 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
196 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
197 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
198 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
199 bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
200 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
201 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
202 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
203 for (i = 0; i < MAXAG; i++)
204 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
205 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
206 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
207
208 /* release the buffer. */
209 release_metapage(mp);
210
211 /* bind the bmap inode and the bmap descriptor to each other. */
212 bmp->db_ipbmap = ipbmap;
213 JFS_SBI(ipbmap->i_sb)->bmap = bmp;
214
215 memset(bmp->db_active, 0, sizeof(bmp->db_active));
216
217 /*
218 * allocate/initialize the bmap lock
219 */
220 BMAP_LOCK_INIT(bmp);
221
222 return (0);
223}
224
225
226/*
227 * NAME: dbUnmount()
228 *
229 * FUNCTION: terminate the block allocation map in preparation for
230 * file system unmount.
231 *
232 * the in-core bmap descriptor is written to disk and
233 * the memory for this descriptor is freed.
234 *
235 * PARAMETERS:
236 * ipbmap - pointer to in-core inode for the block map.
237 *
238 * RETURN VALUES:
239 * 0 - success
240 * -EIO - i/o error
241 */
242int dbUnmount(struct inode *ipbmap, int mounterror)
243{
244 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
245
246 if (!(mounterror || isReadOnly(ipbmap)))
247 dbSync(ipbmap);
248
249 /*
250 * Invalidate the page cache buffers
251 */
252 truncate_inode_pages(ipbmap->i_mapping, 0);
253
254 /* free the memory for the in-memory bmap. */
255 kfree(bmp);
256
257 return (0);
258}
259
260/*
261 * dbSync()
262 */
263int dbSync(struct inode *ipbmap)
264{
265 struct dbmap_disk *dbmp_le;
266 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
267 struct metapage *mp;
268 int i;
269
270 /*
271 * write bmap global control page
272 */
273 /* get the buffer for the on-disk bmap descriptor. */
274 mp = read_metapage(ipbmap,
275 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
276 PSIZE, 0);
277 if (mp == NULL) {
278 jfs_err("dbSync: read_metapage failed!");
279 return -EIO;
280 }
281 /* copy the in-memory version of the bmap to the on-disk version */
282 dbmp_le = (struct dbmap_disk *) mp->data;
283 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
284 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
285 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
286 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
287 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
288 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
289 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
290 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
291 dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
292 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
293 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
294 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
295 for (i = 0; i < MAXAG; i++)
296 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
297 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
298 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
299
300 /* write the buffer */
301 write_metapage(mp);
302
303 /*
304 * write out dirty pages of bmap
305 */
306 filemap_write_and_wait(ipbmap->i_mapping);
307
308 diWriteSpecial(ipbmap, 0);
309
310 return (0);
311}
312
313
314/*
315 * NAME: dbFree()
316 *
317 * FUNCTION: free the specified block range from the working block
318 * allocation map.
319 *
320 * the blocks will be free from the working map one dmap
321 * at a time.
322 *
323 * PARAMETERS:
324 * ip - pointer to in-core inode;
325 * blkno - starting block number to be freed.
326 * nblocks - number of blocks to be freed.
327 *
328 * RETURN VALUES:
329 * 0 - success
330 * -EIO - i/o error
331 */
332int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
333{
334 struct metapage *mp;
335 struct dmap *dp;
336 int nb, rc;
337 s64 lblkno, rem;
338 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
339 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
340
341 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
342
343 /* block to be freed better be within the mapsize. */
344 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
345 IREAD_UNLOCK(ipbmap);
346 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
347 (unsigned long long) blkno,
348 (unsigned long long) nblocks);
349 jfs_error(ip->i_sb,
350 "dbFree: block to be freed is outside the map");
351 return -EIO;
352 }
353
354 /*
355 * free the blocks a dmap at a time.
356 */
357 mp = NULL;
358 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
359 /* release previous dmap if any */
360 if (mp) {
361 write_metapage(mp);
362 }
363
364 /* get the buffer for the current dmap. */
365 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
366 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
367 if (mp == NULL) {
368 IREAD_UNLOCK(ipbmap);
369 return -EIO;
370 }
371 dp = (struct dmap *) mp->data;
372
373 /* determine the number of blocks to be freed from
374 * this dmap.
375 */
376 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
377
378 /* free the blocks. */
379 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
380 jfs_error(ip->i_sb, "dbFree: error in block map\n");
381 release_metapage(mp);
382 IREAD_UNLOCK(ipbmap);
383 return (rc);
384 }
385 }
386
387 /* write the last buffer. */
388 write_metapage(mp);
389
390 IREAD_UNLOCK(ipbmap);
391
392 return (0);
393}
394
395
396/*
397 * NAME: dbUpdatePMap()
398 *
399 * FUNCTION: update the allocation state (free or allocate) of the
400 * specified block range in the persistent block allocation map.
401 *
402 * the blocks will be updated in the persistent map one
403 * dmap at a time.
404 *
405 * PARAMETERS:
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;
412 *
413 * RETURN VALUES:
414 * 0 - success
415 * -EIO - i/o error
416 */
417int
418dbUpdatePMap(struct inode *ipbmap,
419 int free, s64 blkno, s64 nblocks, struct tblock * tblk)
420{
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;
425 u32 mask;
426 struct dmap *dp;
427 struct metapage *mp;
428 struct jfs_log *log;
429 int lsn, difft, diffp;
430 unsigned long flags;
431
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");
439 return -EIO;
440 }
441
442 /* compute delta of transaction lsn from log syncpt */
443 lsn = tblk->lsn;
444 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
445 logdiff(difft, lsn, log);
446
447 /*
448 * update the block state a dmap at a time.
449 */
450 mp = NULL;
451 lastlblkno = 0;
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) {
456 if (mp) {
457 write_metapage(mp);
458 }
459
460 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
461 0);
462 if (mp == NULL)
463 return -EIO;
464 metapage_wait_for_io(mp);
465 }
466 dp = (struct dmap *) mp->data;
467
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.
471 */
472 dbitno = blkno & (BPERDMAP - 1);
473 word = dbitno >> L2DBWORD;
474 nblks = min(rem, (s64)BPERDMAP - dbitno);
475
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.
482 */
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.
487 */
488 wbitno = dbitno & (DBWORD - 1);
489 nbits = min(rbits, DBWORD - wbitno);
490
491 /* check if only part of the word is to be updated. */
492 if (nbits < DBWORD) {
493 /* update (free or allocate) the bits
494 * in this word.
495 */
496 mask =
497 (ONES << (DBWORD - nbits) >> wbitno);
498 if (free)
499 dp->pmap[word] &=
500 cpu_to_le32(~mask);
501 else
502 dp->pmap[word] |=
503 cpu_to_le32(mask);
504
505 word += 1;
506 } else {
507 /* one or more words are to have all
508 * their bits updated. determine how
509 * many words and how many bits.
510 */
511 nwords = rbits >> L2DBWORD;
512 nbits = nwords << L2DBWORD;
513
514 /* update (free or allocate) the bits
515 * in these words.
516 */
517 if (free)
518 memset(&dp->pmap[word], 0,
519 nwords * 4);
520 else
521 memset(&dp->pmap[word], (int) ONES,
522 nwords * 4);
523
524 word += nwords;
525 }
526 }
527
528 /*
529 * update dmap lsn
530 */
531 if (lblkno == lastlblkno)
532 continue;
533
534 lastlblkno = lblkno;
535
536 LOGSYNC_LOCK(log, flags);
537 if (mp->lsn != 0) {
538 /* inherit older/smaller lsn */
539 logdiff(diffp, mp->lsn, log);
540 if (difft < diffp) {
541 mp->lsn = lsn;
542
543 /* move bp after tblock in logsync list */
544 list_move(&mp->synclist, &tblk->synclist);
545 }
546
547 /* inherit younger/larger clsn */
548 logdiff(difft, tblk->clsn, log);
549 logdiff(diffp, mp->clsn, log);
550 if (difft > diffp)
551 mp->clsn = tblk->clsn;
552 } else {
553 mp->log = log;
554 mp->lsn = lsn;
555
556 /* insert bp after tblock in logsync list */
557 log->count++;
558 list_add(&mp->synclist, &tblk->synclist);
559
560 mp->clsn = tblk->clsn;
561 }
562 LOGSYNC_UNLOCK(log, flags);
563 }
564
565 /* write the last buffer. */
566 if (mp) {
567 write_metapage(mp);
568 }
569
570 return (0);
571}
572
573
574/*
575 * NAME: dbNextAG()
576 *
577 * FUNCTION: find the preferred allocation group for new allocations.
578 *
579 * Within the allocation groups, we maintain a preferred
580 * allocation group which consists of a group with at least
581 * average free space. It is the preferred group that we target
582 * new inode allocation towards. The tie-in between inode
583 * allocation and block allocation occurs as we allocate the
584 * first (data) block of an inode and specify the inode (block)
585 * as the allocation hint for this block.
586 *
587 * We try to avoid having more than one open file growing in
588 * an allocation group, as this will lead to fragmentation.
589 * This differs from the old OS/2 method of trying to keep
590 * empty ags around for large allocations.
591 *
592 * PARAMETERS:
593 * ipbmap - pointer to in-core inode for the block map.
594 *
595 * RETURN VALUES:
596 * the preferred allocation group number.
597 */
598int dbNextAG(struct inode *ipbmap)
599{
600 s64 avgfree;
601 int agpref;
602 s64 hwm = 0;
603 int i;
604 int next_best = -1;
605 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
606
607 BMAP_LOCK(bmp);
608
609 /* determine the average number of free blocks within the ags. */
610 avgfree = (u32)bmp->db_nfree / bmp->db_numag;
611
612 /*
613 * if the current preferred ag does not have an active allocator
614 * and has at least average freespace, return it
615 */
616 agpref = bmp->db_agpref;
617 if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
618 (bmp->db_agfree[agpref] >= avgfree))
619 goto unlock;
620
621 /* From the last preferred ag, find the next one with at least
622 * average free space.
623 */
624 for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
625 if (agpref == bmp->db_numag)
626 agpref = 0;
627
628 if (atomic_read(&bmp->db_active[agpref]))
629 /* open file is currently growing in this ag */
630 continue;
631 if (bmp->db_agfree[agpref] >= avgfree) {
632 /* Return this one */
633 bmp->db_agpref = agpref;
634 goto unlock;
635 } else if (bmp->db_agfree[agpref] > hwm) {
636 /* Less than avg. freespace, but best so far */
637 hwm = bmp->db_agfree[agpref];
638 next_best = agpref;
639 }
640 }
641
642 /*
643 * If no inactive ag was found with average freespace, use the
644 * next best
645 */
646 if (next_best != -1)
647 bmp->db_agpref = next_best;
648 /* else leave db_agpref unchanged */
649unlock:
650 BMAP_UNLOCK(bmp);
651
652 /* return the preferred group.
653 */
654 return (bmp->db_agpref);
655}
656
657/*
658 * NAME: dbAlloc()
659 *
660 * FUNCTION: attempt to allocate a specified number of contiguous free
661 * blocks from the working allocation block map.
662 *
663 * the block allocation policy uses hints and a multi-step
664 * approach.
665 *
666 * for allocation requests smaller than the number of blocks
667 * per dmap, we first try to allocate the new blocks
668 * immediately following the hint. if these blocks are not
669 * available, we try to allocate blocks near the hint. if
670 * no blocks near the hint are available, we next try to
671 * allocate within the same dmap as contains the hint.
672 *
673 * if no blocks are available in the dmap or the allocation
674 * request is larger than the dmap size, we try to allocate
675 * within the same allocation group as contains the hint. if
676 * this does not succeed, we finally try to allocate anywhere
677 * within the aggregate.
678 *
679 * we also try to allocate anywhere within the aggregate for
680 * for allocation requests larger than the allocation group
681 * size or requests that specify no hint value.
682 *
683 * PARAMETERS:
684 * ip - pointer to in-core inode;
685 * hint - allocation hint.
686 * nblocks - number of contiguous blocks in the range.
687 * results - on successful return, set to the starting block number
688 * of the newly allocated contiguous range.
689 *
690 * RETURN VALUES:
691 * 0 - success
692 * -ENOSPC - insufficient disk resources
693 * -EIO - i/o error
694 */
695int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
696{
697 int rc, agno;
698 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
699 struct bmap *bmp;
700 struct metapage *mp;
701 s64 lblkno, blkno;
702 struct dmap *dp;
703 int l2nb;
704 s64 mapSize;
705 int writers;
706
707 /* assert that nblocks is valid */
708 assert(nblocks > 0);
709
710 /* get the log2 number of blocks to be allocated.
711 * if the number of blocks is not a log2 multiple,
712 * it will be rounded up to the next log2 multiple.
713 */
714 l2nb = BLKSTOL2(nblocks);
715
716 bmp = JFS_SBI(ip->i_sb)->bmap;
717
718 mapSize = bmp->db_mapsize;
719
720 /* the hint should be within the map */
721 if (hint >= mapSize) {
722 jfs_error(ip->i_sb, "dbAlloc: the hint is outside the map");
723 return -EIO;
724 }
725
726 /* if the number of blocks to be allocated is greater than the
727 * allocation group size, try to allocate anywhere.
728 */
729 if (l2nb > bmp->db_agl2size) {
730 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
731
732 rc = dbAllocAny(bmp, nblocks, l2nb, results);
733
734 goto write_unlock;
735 }
736
737 /*
738 * If no hint, let dbNextAG recommend an allocation group
739 */
740 if (hint == 0)
741 goto pref_ag;
742
743 /* we would like to allocate close to the hint. adjust the
744 * hint to the block following the hint since the allocators
745 * will start looking for free space starting at this point.
746 */
747 blkno = hint + 1;
748
749 if (blkno >= bmp->db_mapsize)
750 goto pref_ag;
751
752 agno = blkno >> bmp->db_agl2size;
753
754 /* check if blkno crosses over into a new allocation group.
755 * if so, check if we should allow allocations within this
756 * allocation group.
757 */
758 if ((blkno & (bmp->db_agsize - 1)) == 0)
759 /* check if the AG is currently being written to.
760 * if so, call dbNextAG() to find a non-busy
761 * AG with sufficient free space.
762 */
763 if (atomic_read(&bmp->db_active[agno]))
764 goto pref_ag;
765
766 /* check if the allocation request size can be satisfied from a
767 * single dmap. if so, try to allocate from the dmap containing
768 * the hint using a tiered strategy.
769 */
770 if (nblocks <= BPERDMAP) {
771 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
772
773 /* get the buffer for the dmap containing the hint.
774 */
775 rc = -EIO;
776 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
777 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
778 if (mp == NULL)
779 goto read_unlock;
780
781 dp = (struct dmap *) mp->data;
782
783 /* first, try to satisfy the allocation request with the
784 * blocks beginning at the hint.
785 */
786 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
787 != -ENOSPC) {
788 if (rc == 0) {
789 *results = blkno;
790 mark_metapage_dirty(mp);
791 }
792
793 release_metapage(mp);
794 goto read_unlock;
795 }
796
797 writers = atomic_read(&bmp->db_active[agno]);
798 if ((writers > 1) ||
799 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
800 /*
801 * Someone else is writing in this allocation
802 * group. To avoid fragmenting, try another ag
803 */
804 release_metapage(mp);
805 IREAD_UNLOCK(ipbmap);
806 goto pref_ag;
807 }
808
809 /* next, try to satisfy the allocation request with blocks
810 * near the hint.
811 */
812 if ((rc =
813 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
814 != -ENOSPC) {
815 if (rc == 0)
816 mark_metapage_dirty(mp);
817
818 release_metapage(mp);
819 goto read_unlock;
820 }
821
822 /* try to satisfy the allocation request with blocks within
823 * the same dmap as the hint.
824 */
825 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
826 != -ENOSPC) {
827 if (rc == 0)
828 mark_metapage_dirty(mp);
829
830 release_metapage(mp);
831 goto read_unlock;
832 }
833
834 release_metapage(mp);
835 IREAD_UNLOCK(ipbmap);
836 }
837
838 /* try to satisfy the allocation request with blocks within
839 * the same allocation group as the hint.
840 */
841 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
842 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
843 goto write_unlock;
844
845 IWRITE_UNLOCK(ipbmap);
846
847
848 pref_ag:
849 /*
850 * Let dbNextAG recommend a preferred allocation group
851 */
852 agno = dbNextAG(ipbmap);
853 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
854
855 /* Try to allocate within this allocation group. if that fails, try to
856 * allocate anywhere in the map.
857 */
858 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
859 rc = dbAllocAny(bmp, nblocks, l2nb, results);
860
861 write_unlock:
862 IWRITE_UNLOCK(ipbmap);
863
864 return (rc);
865
866 read_unlock:
867 IREAD_UNLOCK(ipbmap);
868
869 return (rc);
870}
871
872#ifdef _NOTYET
873/*
874 * NAME: dbAllocExact()
875 *
876 * FUNCTION: try to allocate the requested extent;
877 *
878 * PARAMETERS:
879 * ip - pointer to in-core inode;
880 * blkno - extent address;
881 * nblocks - extent length;
882 *
883 * RETURN VALUES:
884 * 0 - success
885 * -ENOSPC - insufficient disk resources
886 * -EIO - i/o error
887 */
888int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
889{
890 int rc;
891 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
892 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
893 struct dmap *dp;
894 s64 lblkno;
895 struct metapage *mp;
896
897 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
898
899 /*
900 * validate extent request:
901 *
902 * note: defragfs policy:
903 * max 64 blocks will be moved.
904 * allocation request size must be satisfied from a single dmap.
905 */
906 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
907 IREAD_UNLOCK(ipbmap);
908 return -EINVAL;
909 }
910
911 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
912 /* the free space is no longer available */
913 IREAD_UNLOCK(ipbmap);
914 return -ENOSPC;
915 }
916
917 /* read in the dmap covering the extent */
918 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
919 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
920 if (mp == NULL) {
921 IREAD_UNLOCK(ipbmap);
922 return -EIO;
923 }
924 dp = (struct dmap *) mp->data;
925
926 /* try to allocate the requested extent */
927 rc = dbAllocNext(bmp, dp, blkno, nblocks);
928
929 IREAD_UNLOCK(ipbmap);
930
931 if (rc == 0)
932 mark_metapage_dirty(mp);
933
934 release_metapage(mp);
935
936 return (rc);
937}
938#endif /* _NOTYET */
939
940/*
941 * NAME: dbReAlloc()
942 *
943 * FUNCTION: attempt to extend a current allocation by a specified
944 * number of blocks.
945 *
946 * this routine attempts to satisfy the allocation request
947 * by first trying to extend the existing allocation in
948 * place by allocating the additional blocks as the blocks
949 * immediately following the current allocation. if these
950 * blocks are not available, this routine will attempt to
951 * allocate a new set of contiguous blocks large enough
952 * to cover the existing allocation plus the additional
953 * number of blocks required.
954 *
955 * PARAMETERS:
956 * ip - pointer to in-core inode requiring allocation.
957 * blkno - starting block of the current allocation.
958 * nblocks - number of contiguous blocks within the current
959 * allocation.
960 * addnblocks - number of blocks to add to the allocation.
961 * results - on successful return, set to the starting block number
962 * of the existing allocation if the existing allocation
963 * was extended in place or to a newly allocated contiguous
964 * range if the existing allocation could not be extended
965 * in place.
966 *
967 * RETURN VALUES:
968 * 0 - success
969 * -ENOSPC - insufficient disk resources
970 * -EIO - i/o error
971 */
972int
973dbReAlloc(struct inode *ip,
974 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
975{
976 int rc;
977
978 /* try to extend the allocation in place.
979 */
980 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
981 *results = blkno;
982 return (0);
983 } else {
984 if (rc != -ENOSPC)
985 return (rc);
986 }
987
988 /* could not extend the allocation in place, so allocate a
989 * new set of blocks for the entire request (i.e. try to get
990 * a range of contiguous blocks large enough to cover the
991 * existing allocation plus the additional blocks.)
992 */
993 return (dbAlloc
994 (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
995}
996
997
998/*
999 * NAME: dbExtend()
1000 *
1001 * FUNCTION: attempt to extend a current allocation by a specified
1002 * number of blocks.
1003 *
1004 * this routine attempts to satisfy the allocation request
1005 * by first trying to extend the existing allocation in
1006 * place by allocating the additional blocks as the blocks
1007 * immediately following the current allocation.
1008 *
1009 * PARAMETERS:
1010 * ip - pointer to in-core inode requiring allocation.
1011 * blkno - starting block of the current allocation.
1012 * nblocks - number of contiguous blocks within the current
1013 * allocation.
1014 * addnblocks - number of blocks to add to the allocation.
1015 *
1016 * RETURN VALUES:
1017 * 0 - success
1018 * -ENOSPC - insufficient disk resources
1019 * -EIO - i/o error
1020 */
1021static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1022{
1023 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1024 s64 lblkno, lastblkno, extblkno;
1025 uint rel_block;
1026 struct metapage *mp;
1027 struct dmap *dp;
1028 int rc;
1029 struct inode *ipbmap = sbi->ipbmap;
1030 struct bmap *bmp;
1031
1032 /*
1033 * We don't want a non-aligned extent to cross a page boundary
1034 */
1035 if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1036 (rel_block + nblocks + addnblocks > sbi->nbperpage))
1037 return -ENOSPC;
1038
1039 /* get the last block of the current allocation */
1040 lastblkno = blkno + nblocks - 1;
1041
1042 /* determine the block number of the block following
1043 * the existing allocation.
1044 */
1045 extblkno = lastblkno + 1;
1046
1047 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
1048
1049 /* better be within the file system */
1050 bmp = sbi->bmap;
1051 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1052 IREAD_UNLOCK(ipbmap);
1053 jfs_error(ip->i_sb,
1054 "dbExtend: the block is outside the filesystem");
1055 return -EIO;
1056 }
1057
1058 /* we'll attempt to extend the current allocation in place by
1059 * allocating the additional blocks as the blocks immediately
1060 * following the current allocation. we only try to extend the
1061 * current allocation in place if the number of additional blocks
1062 * can fit into a dmap, the last block of the current allocation
1063 * is not the last block of the file system, and the start of the
1064 * inplace extension is not on an allocation group boundary.
1065 */
1066 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1067 (extblkno & (bmp->db_agsize - 1)) == 0) {
1068 IREAD_UNLOCK(ipbmap);
1069 return -ENOSPC;
1070 }
1071
1072 /* get the buffer for the dmap containing the first block
1073 * of the extension.
1074 */
1075 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1076 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1077 if (mp == NULL) {
1078 IREAD_UNLOCK(ipbmap);
1079 return -EIO;
1080 }
1081
1082 dp = (struct dmap *) mp->data;
1083
1084 /* try to allocate the blocks immediately following the
1085 * current allocation.
1086 */
1087 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1088
1089 IREAD_UNLOCK(ipbmap);
1090
1091 /* were we successful ? */
1092 if (rc == 0)
1093 write_metapage(mp);
1094 else
1095 /* we were not successful */
1096 release_metapage(mp);
1097
1098
1099 return (rc);
1100}
1101
1102
1103/*
1104 * NAME: dbAllocNext()
1105 *
1106 * FUNCTION: attempt to allocate the blocks of the specified block
1107 * range within a dmap.
1108 *
1109 * PARAMETERS:
1110 * bmp - pointer to bmap descriptor
1111 * dp - pointer to dmap.
1112 * blkno - starting block number of the range.
1113 * nblocks - number of contiguous free blocks of the range.
1114 *
1115 * RETURN VALUES:
1116 * 0 - success
1117 * -ENOSPC - insufficient disk resources
1118 * -EIO - i/o error
1119 *
1120 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1121 */
1122static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1123 int nblocks)
1124{
1125 int dbitno, word, rembits, nb, nwords, wbitno, nw;
1126 int l2size;
1127 s8 *leaf;
1128 u32 mask;
1129
1130 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1131 jfs_error(bmp->db_ipbmap->i_sb,
1132 "dbAllocNext: Corrupt dmap page");
1133 return -EIO;
1134 }
1135
1136 /* pick up a pointer to the leaves of the dmap tree.
1137 */
1138 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1139
1140 /* determine the bit number and word within the dmap of the
1141 * starting block.
1142 */
1143 dbitno = blkno & (BPERDMAP - 1);
1144 word = dbitno >> L2DBWORD;
1145
1146 /* check if the specified block range is contained within
1147 * this dmap.
1148 */
1149 if (dbitno + nblocks > BPERDMAP)
1150 return -ENOSPC;
1151
1152 /* check if the starting leaf indicates that anything
1153 * is free.
1154 */
1155 if (leaf[word] == NOFREE)
1156 return -ENOSPC;
1157
1158 /* check the dmaps words corresponding to block range to see
1159 * if the block range is free. not all bits of the first and
1160 * last words may be contained within the block range. if this
1161 * is the case, we'll work against those words (i.e. partial first
1162 * and/or last) on an individual basis (a single pass) and examine
1163 * the actual bits to determine if they are free. a single pass
1164 * will be used for all dmap words fully contained within the
1165 * specified range. within this pass, the leaves of the dmap
1166 * tree will be examined to determine if the blocks are free. a
1167 * single leaf may describe the free space of multiple dmap
1168 * words, so we may visit only a subset of the actual leaves
1169 * corresponding to the dmap words of the block range.
1170 */
1171 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1172 /* determine the bit number within the word and
1173 * the number of bits within the word.
1174 */
1175 wbitno = dbitno & (DBWORD - 1);
1176 nb = min(rembits, DBWORD - wbitno);
1177
1178 /* check if only part of the word is to be examined.
1179 */
1180 if (nb < DBWORD) {
1181 /* check if the bits are free.
1182 */
1183 mask = (ONES << (DBWORD - nb) >> wbitno);
1184 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1185 return -ENOSPC;
1186
1187 word += 1;
1188 } else {
1189 /* one or more dmap words are fully contained
1190 * within the block range. determine how many
1191 * words and how many bits.
1192 */
1193 nwords = rembits >> L2DBWORD;
1194 nb = nwords << L2DBWORD;
1195
1196 /* now examine the appropriate leaves to determine
1197 * if the blocks are free.
1198 */
1199 while (nwords > 0) {
1200 /* does the leaf describe any free space ?
1201 */
1202 if (leaf[word] < BUDMIN)
1203 return -ENOSPC;
1204
1205 /* determine the l2 number of bits provided
1206 * by this leaf.
1207 */
1208 l2size =
1209 min((int)leaf[word], NLSTOL2BSZ(nwords));
1210
1211 /* determine how many words were handled.
1212 */
1213 nw = BUDSIZE(l2size, BUDMIN);
1214
1215 nwords -= nw;
1216 word += nw;
1217 }
1218 }
1219 }
1220
1221 /* allocate the blocks.
1222 */
1223 return (dbAllocDmap(bmp, dp, blkno, nblocks));
1224}
1225
1226
1227/*
1228 * NAME: dbAllocNear()
1229 *
1230 * FUNCTION: attempt to allocate a number of contiguous free blocks near
1231 * a specified block (hint) within a dmap.
1232 *
1233 * starting with the dmap leaf that covers the hint, we'll
1234 * check the next four contiguous leaves for sufficient free
1235 * space. if sufficient free space is found, we'll allocate
1236 * the desired free space.
1237 *
1238 * PARAMETERS:
1239 * bmp - pointer to bmap descriptor
1240 * dp - pointer to dmap.
1241 * blkno - block number to allocate near.
1242 * nblocks - actual number of contiguous free blocks desired.
1243 * l2nb - log2 number of contiguous free blocks desired.
1244 * results - on successful return, set to the starting block number
1245 * of the newly allocated range.
1246 *
1247 * RETURN VALUES:
1248 * 0 - success
1249 * -ENOSPC - insufficient disk resources
1250 * -EIO - i/o error
1251 *
1252 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1253 */
1254static int
1255dbAllocNear(struct bmap * bmp,
1256 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1257{
1258 int word, lword, rc;
1259 s8 *leaf;
1260
1261 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1262 jfs_error(bmp->db_ipbmap->i_sb,
1263 "dbAllocNear: Corrupt dmap page");
1264 return -EIO;
1265 }
1266
1267 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1268
1269 /* determine the word within the dmap that holds the hint
1270 * (i.e. blkno). also, determine the last word in the dmap
1271 * that we'll include in our examination.
1272 */
1273 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1274 lword = min(word + 4, LPERDMAP);
1275
1276 /* examine the leaves for sufficient free space.
1277 */
1278 for (; word < lword; word++) {
1279 /* does the leaf describe sufficient free space ?
1280 */
1281 if (leaf[word] < l2nb)
1282 continue;
1283
1284 /* determine the block number within the file system
1285 * of the first block described by this dmap word.
1286 */
1287 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1288
1289 /* if not all bits of the dmap word are free, get the
1290 * starting bit number within the dmap word of the required
1291 * string of free bits and adjust the block number with the
1292 * value.
1293 */
1294 if (leaf[word] < BUDMIN)
1295 blkno +=
1296 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1297
1298 /* allocate the blocks.
1299 */
1300 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1301 *results = blkno;
1302
1303 return (rc);
1304 }
1305
1306 return -ENOSPC;
1307}
1308
1309
1310/*
1311 * NAME: dbAllocAG()
1312 *
1313 * FUNCTION: attempt to allocate the specified number of contiguous
1314 * free blocks within the specified allocation group.
1315 *
1316 * unless the allocation group size is equal to the number
1317 * of blocks per dmap, the dmap control pages will be used to
1318 * find the required free space, if available. we start the
1319 * search at the highest dmap control page level which
1320 * distinctly describes the allocation group's free space
1321 * (i.e. the highest level at which the allocation group's
1322 * free space is not mixed in with that of any other group).
1323 * in addition, we start the search within this level at a
1324 * height of the dmapctl dmtree at which the nodes distinctly
1325 * describe the allocation group's free space. at this height,
1326 * the allocation group's free space may be represented by 1
1327 * or two sub-trees, depending on the allocation group size.
1328 * we search the top nodes of these subtrees left to right for
1329 * sufficient free space. if sufficient free space is found,
1330 * the subtree is searched to find the leftmost leaf that
1331 * has free space. once we have made it to the leaf, we
1332 * move the search to the next lower level dmap control page
1333 * corresponding to this leaf. we continue down the dmap control
1334 * pages until we find the dmap that contains or starts the
1335 * sufficient free space and we allocate at this dmap.
1336 *
1337 * if the allocation group size is equal to the dmap size,
1338 * we'll start at the dmap corresponding to the allocation
1339 * group and attempt the allocation at this level.
1340 *
1341 * the dmap control page search is also not performed if the
1342 * allocation group is completely free and we go to the first
1343 * dmap of the allocation group to do the allocation. this is
1344 * done because the allocation group may be part (not the first
1345 * part) of a larger binary buddy system, causing the dmap
1346 * control pages to indicate no free space (NOFREE) within
1347 * the allocation group.
1348 *
1349 * PARAMETERS:
1350 * bmp - pointer to bmap descriptor
1351 * agno - allocation group number.
1352 * nblocks - actual number of contiguous free blocks desired.
1353 * l2nb - log2 number of contiguous free blocks desired.
1354 * results - on successful return, set to the starting block number
1355 * of the newly allocated range.
1356 *
1357 * RETURN VALUES:
1358 * 0 - success
1359 * -ENOSPC - insufficient disk resources
1360 * -EIO - i/o error
1361 *
1362 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1363 */
1364static int
1365dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1366{
1367 struct metapage *mp;
1368 struct dmapctl *dcp;
1369 int rc, ti, i, k, m, n, agperlev;
1370 s64 blkno, lblkno;
1371 int budmin;
1372
1373 /* allocation request should not be for more than the
1374 * allocation group size.
1375 */
1376 if (l2nb > bmp->db_agl2size) {
1377 jfs_error(bmp->db_ipbmap->i_sb,
1378 "dbAllocAG: allocation request is larger than the "
1379 "allocation group size");
1380 return -EIO;
1381 }
1382
1383 /* determine the starting block number of the allocation
1384 * group.
1385 */
1386 blkno = (s64) agno << bmp->db_agl2size;
1387
1388 /* check if the allocation group size is the minimum allocation
1389 * group size or if the allocation group is completely free. if
1390 * the allocation group size is the minimum size of BPERDMAP (i.e.
1391 * 1 dmap), there is no need to search the dmap control page (below)
1392 * that fully describes the allocation group since the allocation
1393 * group is already fully described by a dmap. in this case, we
1394 * just call dbAllocCtl() to search the dmap tree and allocate the
1395 * required space if available.
1396 *
1397 * if the allocation group is completely free, dbAllocCtl() is
1398 * also called to allocate the required space. this is done for
1399 * two reasons. first, it makes no sense searching the dmap control
1400 * pages for free space when we know that free space exists. second,
1401 * the dmap control pages may indicate that the allocation group
1402 * has no free space if the allocation group is part (not the first
1403 * part) of a larger binary buddy system.
1404 */
1405 if (bmp->db_agsize == BPERDMAP
1406 || bmp->db_agfree[agno] == bmp->db_agsize) {
1407 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1408 if ((rc == -ENOSPC) &&
1409 (bmp->db_agfree[agno] == bmp->db_agsize)) {
1410 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1411 (unsigned long long) blkno,
1412 (unsigned long long) nblocks);
1413 jfs_error(bmp->db_ipbmap->i_sb,
1414 "dbAllocAG: dbAllocCtl failed in free AG");
1415 }
1416 return (rc);
1417 }
1418
1419 /* the buffer for the dmap control page that fully describes the
1420 * allocation group.
1421 */
1422 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1423 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1424 if (mp == NULL)
1425 return -EIO;
1426 dcp = (struct dmapctl *) mp->data;
1427 budmin = dcp->budmin;
1428
1429 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1430 jfs_error(bmp->db_ipbmap->i_sb,
1431 "dbAllocAG: Corrupt dmapctl page");
1432 release_metapage(mp);
1433 return -EIO;
1434 }
1435
1436 /* search the subtree(s) of the dmap control page that describes
1437 * the allocation group, looking for sufficient free space. to begin,
1438 * determine how many allocation groups are represented in a dmap
1439 * control page at the control page level (i.e. L0, L1, L2) that
1440 * fully describes an allocation group. next, determine the starting
1441 * tree index of this allocation group within the control page.
1442 */
1443 agperlev =
1444 (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1445 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1446
1447 /* dmap control page trees fan-out by 4 and a single allocation
1448 * group may be described by 1 or 2 subtrees within the ag level
1449 * dmap control page, depending upon the ag size. examine the ag's
1450 * subtrees for sufficient free space, starting with the leftmost
1451 * subtree.
1452 */
1453 for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1454 /* is there sufficient free space ?
1455 */
1456 if (l2nb > dcp->stree[ti])
1457 continue;
1458
1459 /* sufficient free space found in a subtree. now search down
1460 * the subtree to find the leftmost leaf that describes this
1461 * free space.
1462 */
1463 for (k = bmp->db_agheight; k > 0; k--) {
1464 for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1465 if (l2nb <= dcp->stree[m + n]) {
1466 ti = m + n;
1467 break;
1468 }
1469 }
1470 if (n == 4) {
1471 jfs_error(bmp->db_ipbmap->i_sb,
1472 "dbAllocAG: failed descending stree");
1473 release_metapage(mp);
1474 return -EIO;
1475 }
1476 }
1477
1478 /* determine the block number within the file system
1479 * that corresponds to this leaf.
1480 */
1481 if (bmp->db_aglevel == 2)
1482 blkno = 0;
1483 else if (bmp->db_aglevel == 1)
1484 blkno &= ~(MAXL1SIZE - 1);
1485 else /* bmp->db_aglevel == 0 */
1486 blkno &= ~(MAXL0SIZE - 1);
1487
1488 blkno +=
1489 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1490
1491 /* release the buffer in preparation for going down
1492 * the next level of dmap control pages.
1493 */
1494 release_metapage(mp);
1495
1496 /* check if we need to continue to search down the lower
1497 * level dmap control pages. we need to if the number of
1498 * blocks required is less than maximum number of blocks
1499 * described at the next lower level.
1500 */
1501 if (l2nb < budmin) {
1502
1503 /* search the lower level dmap control pages to get
1504 * the starting block number of the dmap that
1505 * contains or starts off the free space.
1506 */
1507 if ((rc =
1508 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1509 &blkno))) {
1510 if (rc == -ENOSPC) {
1511 jfs_error(bmp->db_ipbmap->i_sb,
1512 "dbAllocAG: control page "
1513 "inconsistent");
1514 return -EIO;
1515 }
1516 return (rc);
1517 }
1518 }
1519
1520 /* allocate the blocks.
1521 */
1522 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1523 if (rc == -ENOSPC) {
1524 jfs_error(bmp->db_ipbmap->i_sb,
1525 "dbAllocAG: unable to allocate blocks");
1526 rc = -EIO;
1527 }
1528 return (rc);
1529 }
1530
1531 /* no space in the allocation group. release the buffer and
1532 * return -ENOSPC.
1533 */
1534 release_metapage(mp);
1535
1536 return -ENOSPC;
1537}
1538
1539
1540/*
1541 * NAME: dbAllocAny()
1542 *
1543 * FUNCTION: attempt to allocate the specified number of contiguous
1544 * free blocks anywhere in the file system.
1545 *
1546 * dbAllocAny() attempts to find the sufficient free space by
1547 * searching down the dmap control pages, starting with the
1548 * highest level (i.e. L0, L1, L2) control page. if free space
1549 * large enough to satisfy the desired free space is found, the
1550 * desired free space is allocated.
1551 *
1552 * PARAMETERS:
1553 * bmp - pointer to bmap descriptor
1554 * nblocks - actual number of contiguous free blocks desired.
1555 * l2nb - log2 number of contiguous free blocks desired.
1556 * results - on successful return, set to the starting block number
1557 * of the newly allocated range.
1558 *
1559 * RETURN VALUES:
1560 * 0 - success
1561 * -ENOSPC - insufficient disk resources
1562 * -EIO - i/o error
1563 *
1564 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1565 */
1566static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1567{
1568 int rc;
1569 s64 blkno = 0;
1570
1571 /* starting with the top level dmap control page, search
1572 * down the dmap control levels for sufficient free space.
1573 * if free space is found, dbFindCtl() returns the starting
1574 * block number of the dmap that contains or starts off the
1575 * range of free space.
1576 */
1577 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1578 return (rc);
1579
1580 /* allocate the blocks.
1581 */
1582 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1583 if (rc == -ENOSPC) {
1584 jfs_error(bmp->db_ipbmap->i_sb,
1585 "dbAllocAny: unable to allocate blocks");
1586 return -EIO;
1587 }
1588 return (rc);
1589}
1590
1591
1592/*
1593 * NAME: dbFindCtl()
1594 *
1595 * FUNCTION: starting at a specified dmap control page level and block
1596 * number, search down the dmap control levels for a range of
1597 * contiguous free blocks large enough to satisfy an allocation
1598 * request for the specified number of free blocks.
1599 *
1600 * if sufficient contiguous free blocks are found, this routine
1601 * returns the starting block number within a dmap page that
1602 * contains or starts a range of contiqious free blocks that
1603 * is sufficient in size.
1604 *
1605 * PARAMETERS:
1606 * bmp - pointer to bmap descriptor
1607 * level - starting dmap control page level.
1608 * l2nb - log2 number of contiguous free blocks desired.
1609 * *blkno - on entry, starting block number for conducting the search.
1610 * on successful return, the first block within a dmap page
1611 * that contains or starts a range of contiguous free blocks.
1612 *
1613 * RETURN VALUES:
1614 * 0 - success
1615 * -ENOSPC - insufficient disk resources
1616 * -EIO - i/o error
1617 *
1618 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1619 */
1620static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1621{
1622 int rc, leafidx, lev;
1623 s64 b, lblkno;
1624 struct dmapctl *dcp;
1625 int budmin;
1626 struct metapage *mp;
1627
1628 /* starting at the specified dmap control page level and block
1629 * number, search down the dmap control levels for the starting
1630 * block number of a dmap page that contains or starts off
1631 * sufficient free blocks.
1632 */
1633 for (lev = level, b = *blkno; lev >= 0; lev--) {
1634 /* get the buffer of the dmap control page for the block
1635 * number and level (i.e. L0, L1, L2).
1636 */
1637 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1638 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1639 if (mp == NULL)
1640 return -EIO;
1641 dcp = (struct dmapctl *) mp->data;
1642 budmin = dcp->budmin;
1643
1644 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1645 jfs_error(bmp->db_ipbmap->i_sb,
1646 "dbFindCtl: Corrupt dmapctl page");
1647 release_metapage(mp);
1648 return -EIO;
1649 }
1650
1651 /* search the tree within the dmap control page for
1652 * sufficient free space. if sufficient free space is found,
1653 * dbFindLeaf() returns the index of the leaf at which
1654 * free space was found.
1655 */
1656 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1657
1658 /* release the buffer.
1659 */
1660 release_metapage(mp);
1661
1662 /* space found ?
1663 */
1664 if (rc) {
1665 if (lev != level) {
1666 jfs_error(bmp->db_ipbmap->i_sb,
1667 "dbFindCtl: dmap inconsistent");
1668 return -EIO;
1669 }
1670 return -ENOSPC;
1671 }
1672
1673 /* adjust the block number to reflect the location within
1674 * the dmap control page (i.e. the leaf) at which free
1675 * space was found.
1676 */
1677 b += (((s64) leafidx) << budmin);
1678
1679 /* we stop the search at this dmap control page level if
1680 * the number of blocks required is greater than or equal
1681 * to the maximum number of blocks described at the next
1682 * (lower) level.
1683 */
1684 if (l2nb >= budmin)
1685 break;
1686 }
1687
1688 *blkno = b;
1689 return (0);
1690}
1691
1692
1693/*
1694 * NAME: dbAllocCtl()
1695 *
1696 * FUNCTION: attempt to allocate a specified number of contiguous
1697 * blocks starting within a specific dmap.
1698 *
1699 * this routine is called by higher level routines that search
1700 * the dmap control pages above the actual dmaps for contiguous
1701 * free space. the result of successful searches by these
1702 * routines are the starting block numbers within dmaps, with
1703 * the dmaps themselves containing the desired contiguous free
1704 * space or starting a contiguous free space of desired size
1705 * that is made up of the blocks of one or more dmaps. these
1706 * calls should not fail due to insufficent resources.
1707 *
1708 * this routine is called in some cases where it is not known
1709 * whether it will fail due to insufficient resources. more
1710 * specifically, this occurs when allocating from an allocation
1711 * group whose size is equal to the number of blocks per dmap.
1712 * in this case, the dmap control pages are not examined prior
1713 * to calling this routine (to save pathlength) and the call
1714 * might fail.
1715 *
1716 * for a request size that fits within a dmap, this routine relies
1717 * upon the dmap's dmtree to find the requested contiguous free
1718 * space. for request sizes that are larger than a dmap, the
1719 * requested free space will start at the first block of the
1720 * first dmap (i.e. blkno).
1721 *
1722 * PARAMETERS:
1723 * bmp - pointer to bmap descriptor
1724 * nblocks - actual number of contiguous free blocks to allocate.
1725 * l2nb - log2 number of contiguous free blocks to allocate.
1726 * blkno - starting block number of the dmap to start the allocation
1727 * from.
1728 * results - on successful return, set to the starting block number
1729 * of the newly allocated range.
1730 *
1731 * RETURN VALUES:
1732 * 0 - success
1733 * -ENOSPC - insufficient disk resources
1734 * -EIO - i/o error
1735 *
1736 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1737 */
1738static int
1739dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1740{
1741 int rc, nb;
1742 s64 b, lblkno, n;
1743 struct metapage *mp;
1744 struct dmap *dp;
1745
1746 /* check if the allocation request is confined to a single dmap.
1747 */
1748 if (l2nb <= L2BPERDMAP) {
1749 /* get the buffer for the dmap.
1750 */
1751 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1752 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1753 if (mp == NULL)
1754 return -EIO;
1755 dp = (struct dmap *) mp->data;
1756
1757 /* try to allocate the blocks.
1758 */
1759 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1760 if (rc == 0)
1761 mark_metapage_dirty(mp);
1762
1763 release_metapage(mp);
1764
1765 return (rc);
1766 }
1767
1768 /* allocation request involving multiple dmaps. it must start on
1769 * a dmap boundary.
1770 */
1771 assert((blkno & (BPERDMAP - 1)) == 0);
1772
1773 /* allocate the blocks dmap by dmap.
1774 */
1775 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1776 /* get the buffer for the dmap.
1777 */
1778 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1779 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1780 if (mp == NULL) {
1781 rc = -EIO;
1782 goto backout;
1783 }
1784 dp = (struct dmap *) mp->data;
1785
1786 /* the dmap better be all free.
1787 */
1788 if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1789 release_metapage(mp);
1790 jfs_error(bmp->db_ipbmap->i_sb,
1791 "dbAllocCtl: the dmap is not all free");
1792 rc = -EIO;
1793 goto backout;
1794 }
1795
1796 /* determine how many blocks to allocate from this dmap.
1797 */
1798 nb = min(n, (s64)BPERDMAP);
1799
1800 /* allocate the blocks from the dmap.
1801 */
1802 if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1803 release_metapage(mp);
1804 goto backout;
1805 }
1806
1807 /* write the buffer.
1808 */
1809 write_metapage(mp);
1810 }
1811
1812 /* set the results (starting block number) and return.
1813 */
1814 *results = blkno;
1815 return (0);
1816
1817 /* something failed in handling an allocation request involving
1818 * multiple dmaps. we'll try to clean up by backing out any
1819 * allocation that has already happened for this request. if
1820 * we fail in backing out the allocation, we'll mark the file
1821 * system to indicate that blocks have been leaked.
1822 */
1823 backout:
1824
1825 /* try to backout the allocations dmap by dmap.
1826 */
1827 for (n = nblocks - n, b = blkno; n > 0;
1828 n -= BPERDMAP, b += BPERDMAP) {
1829 /* get the buffer for this dmap.
1830 */
1831 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1832 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1833 if (mp == NULL) {
1834 /* could not back out. mark the file system
1835 * to indicate that we have leaked blocks.
1836 */
1837 jfs_error(bmp->db_ipbmap->i_sb,
1838 "dbAllocCtl: I/O Error: Block Leakage.");
1839 continue;
1840 }
1841 dp = (struct dmap *) mp->data;
1842
1843 /* free the blocks is this dmap.
1844 */
1845 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1846 /* could not back out. mark the file system
1847 * to indicate that we have leaked blocks.
1848 */
1849 release_metapage(mp);
1850 jfs_error(bmp->db_ipbmap->i_sb,
1851 "dbAllocCtl: Block Leakage.");
1852 continue;
1853 }
1854
1855 /* write the buffer.
1856 */
1857 write_metapage(mp);
1858 }
1859
1860 return (rc);
1861}
1862
1863
1864/*
1865 * NAME: dbAllocDmapLev()
1866 *
1867 * FUNCTION: attempt to allocate a specified number of contiguous blocks
1868 * from a specified dmap.
1869 *
1870 * this routine checks if the contiguous blocks are available.
1871 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1872 * returned.
1873 *
1874 * PARAMETERS:
1875 * mp - pointer to bmap descriptor
1876 * dp - pointer to dmap to attempt to allocate blocks from.
1877 * l2nb - log2 number of contiguous block desired.
1878 * nblocks - actual number of contiguous block desired.
1879 * results - on successful return, set to the starting block number
1880 * of the newly allocated range.
1881 *
1882 * RETURN VALUES:
1883 * 0 - success
1884 * -ENOSPC - insufficient disk resources
1885 * -EIO - i/o error
1886 *
1887 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1888 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1889 */
1890static int
1891dbAllocDmapLev(struct bmap * bmp,
1892 struct dmap * dp, int nblocks, int l2nb, s64 * results)
1893{
1894 s64 blkno;
1895 int leafidx, rc;
1896
1897 /* can't be more than a dmaps worth of blocks */
1898 assert(l2nb <= L2BPERDMAP);
1899
1900 /* search the tree within the dmap page for sufficient
1901 * free space. if sufficient free space is found, dbFindLeaf()
1902 * returns the index of the leaf at which free space was found.
1903 */
1904 if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1905 return -ENOSPC;
1906
1907 /* determine the block number within the file system corresponding
1908 * to the leaf at which free space was found.
1909 */
1910 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1911
1912 /* if not all bits of the dmap word are free, get the starting
1913 * bit number within the dmap word of the required string of free
1914 * bits and adjust the block number with this value.
1915 */
1916 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1917 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1918
1919 /* allocate the blocks */
1920 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1921 *results = blkno;
1922
1923 return (rc);
1924}
1925
1926
1927/*
1928 * NAME: dbAllocDmap()
1929 *
1930 * FUNCTION: adjust the disk allocation map to reflect the allocation
1931 * of a specified block range within a dmap.
1932 *
1933 * this routine allocates the specified blocks from the dmap
1934 * through a call to dbAllocBits(). if the allocation of the
1935 * block range causes the maximum string of free blocks within
1936 * the dmap to change (i.e. the value of the root of the dmap's
1937 * dmtree), this routine will cause this change to be reflected
1938 * up through the appropriate levels of the dmap control pages
1939 * by a call to dbAdjCtl() for the L0 dmap control page that
1940 * covers this dmap.
1941 *
1942 * PARAMETERS:
1943 * bmp - pointer to bmap descriptor
1944 * dp - pointer to dmap to allocate the block range from.
1945 * blkno - starting block number of the block to be allocated.
1946 * nblocks - number of blocks to be allocated.
1947 *
1948 * RETURN VALUES:
1949 * 0 - success
1950 * -EIO - i/o error
1951 *
1952 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
1953 */
1954static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
1955 int nblocks)
1956{
1957 s8 oldroot;
1958 int rc;
1959
1960 /* save the current value of the root (i.e. maximum free string)
1961 * of the dmap tree.
1962 */
1963 oldroot = dp->tree.stree[ROOT];
1964
1965 /* allocate the specified (blocks) bits */
1966 dbAllocBits(bmp, dp, blkno, nblocks);
1967
1968 /* if the root has not changed, done. */
1969 if (dp->tree.stree[ROOT] == oldroot)
1970 return (0);
1971
1972 /* root changed. bubble the change up to the dmap control pages.
1973 * if the adjustment of the upper level control pages fails,
1974 * backout the bit allocation (thus making everything consistent).
1975 */
1976 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
1977 dbFreeBits(bmp, dp, blkno, nblocks);
1978
1979 return (rc);
1980}
1981
1982
1983/*
1984 * NAME: dbFreeDmap()
1985 *
1986 * FUNCTION: adjust the disk allocation map to reflect the allocation
1987 * of a specified block range within a dmap.
1988 *
1989 * this routine frees the specified blocks from the dmap through
1990 * a call to dbFreeBits(). if the deallocation of the block range
1991 * causes the maximum string of free blocks within the dmap to
1992 * change (i.e. the value of the root of the dmap's dmtree), this
1993 * routine will cause this change to be reflected up through the
1994 * appropriate levels of the dmap control pages by a call to
1995 * dbAdjCtl() for the L0 dmap control page that covers this dmap.
1996 *
1997 * PARAMETERS:
1998 * bmp - pointer to bmap descriptor
1999 * dp - pointer to dmap to free the block range from.
2000 * blkno - starting block number of the block to be freed.
2001 * nblocks - number of blocks to be freed.
2002 *
2003 * RETURN VALUES:
2004 * 0 - success
2005 * -EIO - i/o error
2006 *
2007 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2008 */
2009static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2010 int nblocks)
2011{
2012 s8 oldroot;
2013 int rc = 0, word;
2014
2015 /* save the current value of the root (i.e. maximum free string)
2016 * of the dmap tree.
2017 */
2018 oldroot = dp->tree.stree[ROOT];
2019
2020 /* free the specified (blocks) bits */
2021 rc = dbFreeBits(bmp, dp, blkno, nblocks);
2022
2023 /* if error or the root has not changed, done. */
2024 if (rc || (dp->tree.stree[ROOT] == oldroot))
2025 return (rc);
2026
2027 /* root changed. bubble the change up to the dmap control pages.
2028 * if the adjustment of the upper level control pages fails,
2029 * backout the deallocation.
2030 */
2031 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2032 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2033
2034 /* as part of backing out the deallocation, we will have
2035 * to back split the dmap tree if the deallocation caused
2036 * the freed blocks to become part of a larger binary buddy
2037 * system.
2038 */
2039 if (dp->tree.stree[word] == NOFREE)
2040 dbBackSplit((dmtree_t *) & dp->tree, word);
2041
2042 dbAllocBits(bmp, dp, blkno, nblocks);
2043 }
2044
2045 return (rc);
2046}
2047
2048
2049/*
2050 * NAME: dbAllocBits()
2051 *
2052 * FUNCTION: allocate a specified block range from a dmap.
2053 *
2054 * this routine updates the dmap to reflect the working
2055 * state allocation of the specified block range. it directly
2056 * updates the bits of the working map and causes the adjustment
2057 * of the binary buddy system described by the dmap's dmtree
2058 * leaves to reflect the bits allocated. it also causes the
2059 * dmap's dmtree, as a whole, to reflect the allocated range.
2060 *
2061 * PARAMETERS:
2062 * bmp - pointer to bmap descriptor
2063 * dp - pointer to dmap to allocate bits from.
2064 * blkno - starting block number of the bits to be allocated.
2065 * nblocks - number of bits to be allocated.
2066 *
2067 * RETURN VALUES: none
2068 *
2069 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2070 */
2071static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2072 int nblocks)
2073{
2074 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2075 dmtree_t *tp = (dmtree_t *) & dp->tree;
2076 int size;
2077 s8 *leaf;
2078
2079 /* pick up a pointer to the leaves of the dmap tree */
2080 leaf = dp->tree.stree + LEAFIND;
2081
2082 /* determine the bit number and word within the dmap of the
2083 * starting block.
2084 */
2085 dbitno = blkno & (BPERDMAP - 1);
2086 word = dbitno >> L2DBWORD;
2087
2088 /* block range better be within the dmap */
2089 assert(dbitno + nblocks <= BPERDMAP);
2090
2091 /* allocate the bits of the dmap's words corresponding to the block
2092 * range. not all bits of the first and last words may be contained
2093 * within the block range. if this is the case, we'll work against
2094 * those words (i.e. partial first and/or last) on an individual basis
2095 * (a single pass), allocating the bits of interest by hand and
2096 * updating the leaf corresponding to the dmap word. a single pass
2097 * will be used for all dmap words fully contained within the
2098 * specified range. within this pass, the bits of all fully contained
2099 * dmap words will be marked as free in a single shot and the leaves
2100 * will be updated. a single leaf may describe the free space of
2101 * multiple dmap words, so we may update only a subset of the actual
2102 * leaves corresponding to the dmap words of the block range.
2103 */
2104 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2105 /* determine the bit number within the word and
2106 * the number of bits within the word.
2107 */
2108 wbitno = dbitno & (DBWORD - 1);
2109 nb = min(rembits, DBWORD - wbitno);
2110
2111 /* check if only part of a word is to be allocated.
2112 */
2113 if (nb < DBWORD) {
2114 /* allocate (set to 1) the appropriate bits within
2115 * this dmap word.
2116 */
2117 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2118 >> wbitno);
2119
2120 /* update the leaf for this dmap word. in addition
2121 * to setting the leaf value to the binary buddy max
2122 * of the updated dmap word, dbSplit() will split
2123 * the binary system of the leaves if need be.
2124 */
2125 dbSplit(tp, word, BUDMIN,
2126 dbMaxBud((u8 *) & dp->wmap[word]));
2127
2128 word += 1;
2129 } else {
2130 /* one or more dmap words are fully contained
2131 * within the block range. determine how many
2132 * words and allocate (set to 1) the bits of these
2133 * words.
2134 */
2135 nwords = rembits >> L2DBWORD;
2136 memset(&dp->wmap[word], (int) ONES, nwords * 4);
2137
2138 /* determine how many bits.
2139 */
2140 nb = nwords << L2DBWORD;
2141
2142 /* now update the appropriate leaves to reflect
2143 * the allocated words.
2144 */
2145 for (; nwords > 0; nwords -= nw) {
2146 if (leaf[word] < BUDMIN) {
2147 jfs_error(bmp->db_ipbmap->i_sb,
2148 "dbAllocBits: leaf page "
2149 "corrupt");
2150 break;
2151 }
2152
2153 /* determine what the leaf value should be
2154 * updated to as the minimum of the l2 number
2155 * of bits being allocated and the l2 number
2156 * of bits currently described by this leaf.
2157 */
2158 size = min((int)leaf[word], NLSTOL2BSZ(nwords));
2159
2160 /* update the leaf to reflect the allocation.
2161 * in addition to setting the leaf value to
2162 * NOFREE, dbSplit() will split the binary
2163 * system of the leaves to reflect the current
2164 * allocation (size).
2165 */
2166 dbSplit(tp, word, size, NOFREE);
2167
2168 /* get the number of dmap words handled */
2169 nw = BUDSIZE(size, BUDMIN);
2170 word += nw;
2171 }
2172 }
2173 }
2174
2175 /* update the free count for this dmap */
2176 le32_add_cpu(&dp->nfree, -nblocks);
2177
2178 BMAP_LOCK(bmp);
2179
2180 /* if this allocation group is completely free,
2181 * update the maximum allocation group number if this allocation
2182 * group is the new max.
2183 */
2184 agno = blkno >> bmp->db_agl2size;
2185 if (agno > bmp->db_maxag)
2186 bmp->db_maxag = agno;
2187
2188 /* update the free count for the allocation group and map */
2189 bmp->db_agfree[agno] -= nblocks;
2190 bmp->db_nfree -= nblocks;
2191
2192 BMAP_UNLOCK(bmp);
2193}
2194
2195
2196/*
2197 * NAME: dbFreeBits()
2198 *
2199 * FUNCTION: free a specified block range from a dmap.
2200 *
2201 * this routine updates the dmap to reflect the working
2202 * state allocation of the specified block range. it directly
2203 * updates the bits of the working map and causes the adjustment
2204 * of the binary buddy system described by the dmap's dmtree
2205 * leaves to reflect the bits freed. it also causes the dmap's
2206 * dmtree, as a whole, to reflect the deallocated range.
2207 *
2208 * PARAMETERS:
2209 * bmp - pointer to bmap descriptor
2210 * dp - pointer to dmap to free bits from.
2211 * blkno - starting block number of the bits to be freed.
2212 * nblocks - number of bits to be freed.
2213 *
2214 * RETURN VALUES: 0 for success
2215 *
2216 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2217 */
2218static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2219 int nblocks)
2220{
2221 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2222 dmtree_t *tp = (dmtree_t *) & dp->tree;
2223 int rc = 0;
2224 int size;
2225
2226 /* determine the bit number and word within the dmap of the
2227 * starting block.
2228 */
2229 dbitno = blkno & (BPERDMAP - 1);
2230 word = dbitno >> L2DBWORD;
2231
2232 /* block range better be within the dmap.
2233 */
2234 assert(dbitno + nblocks <= BPERDMAP);
2235
2236 /* free the bits of the dmaps words corresponding to the block range.
2237 * not all bits of the first and last words may be contained within
2238 * the block range. if this is the case, we'll work against those
2239 * words (i.e. partial first and/or last) on an individual basis
2240 * (a single pass), freeing the bits of interest by hand and updating
2241 * the leaf corresponding to the dmap word. a single pass will be used
2242 * for all dmap words fully contained within the specified range.
2243 * within this pass, the bits of all fully contained dmap words will
2244 * be marked as free in a single shot and the leaves will be updated. a
2245 * single leaf may describe the free space of multiple dmap words,
2246 * so we may update only a subset of the actual leaves corresponding
2247 * to the dmap words of the block range.
2248 *
2249 * dbJoin() is used to update leaf values and will join the binary
2250 * buddy system of the leaves if the new leaf values indicate this
2251 * should be done.
2252 */
2253 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2254 /* determine the bit number within the word and
2255 * the number of bits within the word.
2256 */
2257 wbitno = dbitno & (DBWORD - 1);
2258 nb = min(rembits, DBWORD - wbitno);
2259
2260 /* check if only part of a word is to be freed.
2261 */
2262 if (nb < DBWORD) {
2263 /* free (zero) the appropriate bits within this
2264 * dmap word.
2265 */
2266 dp->wmap[word] &=
2267 cpu_to_le32(~(ONES << (DBWORD - nb)
2268 >> wbitno));
2269
2270 /* update the leaf for this dmap word.
2271 */
2272 rc = dbJoin(tp, word,
2273 dbMaxBud((u8 *) & dp->wmap[word]));
2274 if (rc)
2275 return rc;
2276
2277 word += 1;
2278 } else {
2279 /* one or more dmap words are fully contained
2280 * within the block range. determine how many
2281 * words and free (zero) the bits of these words.
2282 */
2283 nwords = rembits >> L2DBWORD;
2284 memset(&dp->wmap[word], 0, nwords * 4);
2285
2286 /* determine how many bits.
2287 */
2288 nb = nwords << L2DBWORD;
2289
2290 /* now update the appropriate leaves to reflect
2291 * the freed words.
2292 */
2293 for (; nwords > 0; nwords -= nw) {
2294 /* determine what the leaf value should be
2295 * updated to as the minimum of the l2 number
2296 * of bits being freed and the l2 (max) number
2297 * of bits that can be described by this leaf.
2298 */
2299 size =
2300 min(LITOL2BSZ
2301 (word, L2LPERDMAP, BUDMIN),
2302 NLSTOL2BSZ(nwords));
2303
2304 /* update the leaf.
2305 */
2306 rc = dbJoin(tp, word, size);
2307 if (rc)
2308 return rc;
2309
2310 /* get the number of dmap words handled.
2311 */
2312 nw = BUDSIZE(size, BUDMIN);
2313 word += nw;
2314 }
2315 }
2316 }
2317
2318 /* update the free count for this dmap.
2319 */
2320 le32_add_cpu(&dp->nfree, nblocks);
2321
2322 BMAP_LOCK(bmp);
2323
2324 /* update the free count for the allocation group and
2325 * map.
2326 */
2327 agno = blkno >> bmp->db_agl2size;
2328 bmp->db_nfree += nblocks;
2329 bmp->db_agfree[agno] += nblocks;
2330
2331 /* check if this allocation group is not completely free and
2332 * if it is currently the maximum (rightmost) allocation group.
2333 * if so, establish the new maximum allocation group number by
2334 * searching left for the first allocation group with allocation.
2335 */
2336 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2337 (agno == bmp->db_numag - 1 &&
2338 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2339 while (bmp->db_maxag > 0) {
2340 bmp->db_maxag -= 1;
2341 if (bmp->db_agfree[bmp->db_maxag] !=
2342 bmp->db_agsize)
2343 break;
2344 }
2345
2346 /* re-establish the allocation group preference if the
2347 * current preference is right of the maximum allocation
2348 * group.
2349 */
2350 if (bmp->db_agpref > bmp->db_maxag)
2351 bmp->db_agpref = bmp->db_maxag;
2352 }
2353
2354 BMAP_UNLOCK(bmp);
2355
2356 return 0;
2357}
2358
2359
2360/*
2361 * NAME: dbAdjCtl()
2362 *
2363 * FUNCTION: adjust a dmap control page at a specified level to reflect
2364 * the change in a lower level dmap or dmap control page's
2365 * maximum string of free blocks (i.e. a change in the root
2366 * of the lower level object's dmtree) due to the allocation
2367 * or deallocation of a range of blocks with a single dmap.
2368 *
2369 * on entry, this routine is provided with the new value of
2370 * the lower level dmap or dmap control page root and the
2371 * starting block number of the block range whose allocation
2372 * or deallocation resulted in the root change. this range
2373 * is respresented by a single leaf of the current dmapctl
2374 * and the leaf will be updated with this value, possibly
2375 * causing a binary buddy system within the leaves to be
2376 * split or joined. the update may also cause the dmapctl's
2377 * dmtree to be updated.
2378 *
2379 * if the adjustment of the dmap control page, itself, causes its
2380 * root to change, this change will be bubbled up to the next dmap
2381 * control level by a recursive call to this routine, specifying
2382 * the new root value and the next dmap control page level to
2383 * be adjusted.
2384 * PARAMETERS:
2385 * bmp - pointer to bmap descriptor
2386 * blkno - the first block of a block range within a dmap. it is
2387 * the allocation or deallocation of this block range that
2388 * requires the dmap control page to be adjusted.
2389 * newval - the new value of the lower level dmap or dmap control
2390 * page root.
2391 * alloc - 'true' if adjustment is due to an allocation.
2392 * level - current level of dmap control page (i.e. L0, L1, L2) to
2393 * be adjusted.
2394 *
2395 * RETURN VALUES:
2396 * 0 - success
2397 * -EIO - i/o error
2398 *
2399 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2400 */
2401static int
2402dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2403{
2404 struct metapage *mp;
2405 s8 oldroot;
2406 int oldval;
2407 s64 lblkno;
2408 struct dmapctl *dcp;
2409 int rc, leafno, ti;
2410
2411 /* get the buffer for the dmap control page for the specified
2412 * block number and control page level.
2413 */
2414 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2415 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2416 if (mp == NULL)
2417 return -EIO;
2418 dcp = (struct dmapctl *) mp->data;
2419
2420 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2421 jfs_error(bmp->db_ipbmap->i_sb,
2422 "dbAdjCtl: Corrupt dmapctl page");
2423 release_metapage(mp);
2424 return -EIO;
2425 }
2426
2427 /* determine the leaf number corresponding to the block and
2428 * the index within the dmap control tree.
2429 */
2430 leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2431 ti = leafno + le32_to_cpu(dcp->leafidx);
2432
2433 /* save the current leaf value and the current root level (i.e.
2434 * maximum l2 free string described by this dmapctl).
2435 */
2436 oldval = dcp->stree[ti];
2437 oldroot = dcp->stree[ROOT];
2438
2439 /* check if this is a control page update for an allocation.
2440 * if so, update the leaf to reflect the new leaf value using
2441 * dbSplit(); otherwise (deallocation), use dbJoin() to update
2442 * the leaf with the new value. in addition to updating the
2443 * leaf, dbSplit() will also split the binary buddy system of
2444 * the leaves, if required, and bubble new values within the
2445 * dmapctl tree, if required. similarly, dbJoin() will join
2446 * the binary buddy system of leaves and bubble new values up
2447 * the dmapctl tree as required by the new leaf value.
2448 */
2449 if (alloc) {
2450 /* check if we are in the middle of a binary buddy
2451 * system. this happens when we are performing the
2452 * first allocation out of an allocation group that
2453 * is part (not the first part) of a larger binary
2454 * buddy system. if we are in the middle, back split
2455 * the system prior to calling dbSplit() which assumes
2456 * that it is at the front of a binary buddy system.
2457 */
2458 if (oldval == NOFREE) {
2459 rc = dbBackSplit((dmtree_t *) dcp, leafno);
2460 if (rc)
2461 return rc;
2462 oldval = dcp->stree[ti];
2463 }
2464 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2465 } else {
2466 rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2467 if (rc)
2468 return rc;
2469 }
2470
2471 /* check if the root of the current dmap control page changed due
2472 * to the update and if the current dmap control page is not at
2473 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
2474 * root changed and this is not the top level), call this routine
2475 * again (recursion) for the next higher level of the mapping to
2476 * reflect the change in root for the current dmap control page.
2477 */
2478 if (dcp->stree[ROOT] != oldroot) {
2479 /* are we below the top level of the map. if so,
2480 * bubble the root up to the next higher level.
2481 */
2482 if (level < bmp->db_maxlevel) {
2483 /* bubble up the new root of this dmap control page to
2484 * the next level.
2485 */
2486 if ((rc =
2487 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2488 level + 1))) {
2489 /* something went wrong in bubbling up the new
2490 * root value, so backout the changes to the
2491 * current dmap control page.
2492 */
2493 if (alloc) {
2494 dbJoin((dmtree_t *) dcp, leafno,
2495 oldval);
2496 } else {
2497 /* the dbJoin() above might have
2498 * caused a larger binary buddy system
2499 * to form and we may now be in the
2500 * middle of it. if this is the case,
2501 * back split the buddies.
2502 */
2503 if (dcp->stree[ti] == NOFREE)
2504 dbBackSplit((dmtree_t *)
2505 dcp, leafno);
2506 dbSplit((dmtree_t *) dcp, leafno,
2507 dcp->budmin, oldval);
2508 }
2509
2510 /* release the buffer and return the error.
2511 */
2512 release_metapage(mp);
2513 return (rc);
2514 }
2515 } else {
2516 /* we're at the top level of the map. update
2517 * the bmap control page to reflect the size
2518 * of the maximum free buddy system.
2519 */
2520 assert(level == bmp->db_maxlevel);
2521 if (bmp->db_maxfreebud != oldroot) {
2522 jfs_error(bmp->db_ipbmap->i_sb,
2523 "dbAdjCtl: the maximum free buddy is "
2524 "not the old root");
2525 }
2526 bmp->db_maxfreebud = dcp->stree[ROOT];
2527 }
2528 }
2529
2530 /* write the buffer.
2531 */
2532 write_metapage(mp);
2533
2534 return (0);
2535}
2536
2537
2538/*
2539 * NAME: dbSplit()
2540 *
2541 * FUNCTION: update the leaf of a dmtree with a new value, splitting
2542 * the leaf from the binary buddy system of the dmtree's
2543 * leaves, as required.
2544 *
2545 * PARAMETERS:
2546 * tp - pointer to the tree containing the leaf.
2547 * leafno - the number of the leaf to be updated.
2548 * splitsz - the size the binary buddy system starting at the leaf
2549 * must be split to, specified as the log2 number of blocks.
2550 * newval - the new value for the leaf.
2551 *
2552 * RETURN VALUES: none
2553 *
2554 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2555 */
2556static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2557{
2558 int budsz;
2559 int cursz;
2560 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2561
2562 /* check if the leaf needs to be split.
2563 */
2564 if (leaf[leafno] > tp->dmt_budmin) {
2565 /* the split occurs by cutting the buddy system in half
2566 * at the specified leaf until we reach the specified
2567 * size. pick up the starting split size (current size
2568 * - 1 in l2) and the corresponding buddy size.
2569 */
2570 cursz = leaf[leafno] - 1;
2571 budsz = BUDSIZE(cursz, tp->dmt_budmin);
2572
2573 /* split until we reach the specified size.
2574 */
2575 while (cursz >= splitsz) {
2576 /* update the buddy's leaf with its new value.
2577 */
2578 dbAdjTree(tp, leafno ^ budsz, cursz);
2579
2580 /* on to the next size and buddy.
2581 */
2582 cursz -= 1;
2583 budsz >>= 1;
2584 }
2585 }
2586
2587 /* adjust the dmap tree to reflect the specified leaf's new
2588 * value.
2589 */
2590 dbAdjTree(tp, leafno, newval);
2591}
2592
2593
2594/*
2595 * NAME: dbBackSplit()
2596 *
2597 * FUNCTION: back split the binary buddy system of dmtree leaves
2598 * that hold a specified leaf until the specified leaf
2599 * starts its own binary buddy system.
2600 *
2601 * the allocators typically perform allocations at the start
2602 * of binary buddy systems and dbSplit() is used to accomplish
2603 * any required splits. in some cases, however, allocation
2604 * may occur in the middle of a binary system and requires a
2605 * back split, with the split proceeding out from the middle of
2606 * the system (less efficient) rather than the start of the
2607 * system (more efficient). the cases in which a back split
2608 * is required are rare and are limited to the first allocation
2609 * within an allocation group which is a part (not first part)
2610 * of a larger binary buddy system and a few exception cases
2611 * in which a previous join operation must be backed out.
2612 *
2613 * PARAMETERS:
2614 * tp - pointer to the tree containing the leaf.
2615 * leafno - the number of the leaf to be updated.
2616 *
2617 * RETURN VALUES: none
2618 *
2619 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2620 */
2621static int dbBackSplit(dmtree_t * tp, int leafno)
2622{
2623 int budsz, bud, w, bsz, size;
2624 int cursz;
2625 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2626
2627 /* leaf should be part (not first part) of a binary
2628 * buddy system.
2629 */
2630 assert(leaf[leafno] == NOFREE);
2631
2632 /* the back split is accomplished by iteratively finding the leaf
2633 * that starts the buddy system that contains the specified leaf and
2634 * splitting that system in two. this iteration continues until
2635 * the specified leaf becomes the start of a buddy system.
2636 *
2637 * determine maximum possible l2 size for the specified leaf.
2638 */
2639 size =
2640 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2641 tp->dmt_budmin);
2642
2643 /* determine the number of leaves covered by this size. this
2644 * is the buddy size that we will start with as we search for
2645 * the buddy system that contains the specified leaf.
2646 */
2647 budsz = BUDSIZE(size, tp->dmt_budmin);
2648
2649 /* back split.
2650 */
2651 while (leaf[leafno] == NOFREE) {
2652 /* find the leftmost buddy leaf.
2653 */
2654 for (w = leafno, bsz = budsz;; bsz <<= 1,
2655 w = (w < bud) ? w : bud) {
2656 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2657 jfs_err("JFS: block map error in dbBackSplit");
2658 return -EIO;
2659 }
2660
2661 /* determine the buddy.
2662 */
2663 bud = w ^ bsz;
2664
2665 /* check if this buddy is the start of the system.
2666 */
2667 if (leaf[bud] != NOFREE) {
2668 /* split the leaf at the start of the
2669 * system in two.
2670 */
2671 cursz = leaf[bud] - 1;
2672 dbSplit(tp, bud, cursz, cursz);
2673 break;
2674 }
2675 }
2676 }
2677
2678 if (leaf[leafno] != size) {
2679 jfs_err("JFS: wrong leaf value in dbBackSplit");
2680 return -EIO;
2681 }
2682 return 0;
2683}
2684
2685
2686/*
2687 * NAME: dbJoin()
2688 *
2689 * FUNCTION: update the leaf of a dmtree with a new value, joining
2690 * the leaf with other leaves of the dmtree into a multi-leaf
2691 * binary buddy system, as required.
2692 *
2693 * PARAMETERS:
2694 * tp - pointer to the tree containing the leaf.
2695 * leafno - the number of the leaf to be updated.
2696 * newval - the new value for the leaf.
2697 *
2698 * RETURN VALUES: none
2699 */
2700static int dbJoin(dmtree_t * tp, int leafno, int newval)
2701{
2702 int budsz, buddy;
2703 s8 *leaf;
2704
2705 /* can the new leaf value require a join with other leaves ?
2706 */
2707 if (newval >= tp->dmt_budmin) {
2708 /* pickup a pointer to the leaves of the tree.
2709 */
2710 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2711
2712 /* try to join the specified leaf into a large binary
2713 * buddy system. the join proceeds by attempting to join
2714 * the specified leafno with its buddy (leaf) at new value.
2715 * if the join occurs, we attempt to join the left leaf
2716 * of the joined buddies with its buddy at new value + 1.
2717 * we continue to join until we find a buddy that cannot be
2718 * joined (does not have a value equal to the size of the
2719 * last join) or until all leaves have been joined into a
2720 * single system.
2721 *
2722 * get the buddy size (number of words covered) of
2723 * the new value.
2724 */
2725 budsz = BUDSIZE(newval, tp->dmt_budmin);
2726
2727 /* try to join.
2728 */
2729 while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2730 /* get the buddy leaf.
2731 */
2732 buddy = leafno ^ budsz;
2733
2734 /* if the leaf's new value is greater than its
2735 * buddy's value, we join no more.
2736 */
2737 if (newval > leaf[buddy])
2738 break;
2739
2740 /* It shouldn't be less */
2741 if (newval < leaf[buddy])
2742 return -EIO;
2743
2744 /* check which (leafno or buddy) is the left buddy.
2745 * the left buddy gets to claim the blocks resulting
2746 * from the join while the right gets to claim none.
2747 * the left buddy is also eligible to participate in
2748 * a join at the next higher level while the right
2749 * is not.
2750 *
2751 */
2752 if (leafno < buddy) {
2753 /* leafno is the left buddy.
2754 */
2755 dbAdjTree(tp, buddy, NOFREE);
2756 } else {
2757 /* buddy is the left buddy and becomes
2758 * leafno.
2759 */
2760 dbAdjTree(tp, leafno, NOFREE);
2761 leafno = buddy;
2762 }
2763
2764 /* on to try the next join.
2765 */
2766 newval += 1;
2767 budsz <<= 1;
2768 }
2769 }
2770
2771 /* update the leaf value.
2772 */
2773 dbAdjTree(tp, leafno, newval);
2774
2775 return 0;
2776}
2777
2778
2779/*
2780 * NAME: dbAdjTree()
2781 *
2782 * FUNCTION: update a leaf of a dmtree with a new value, adjusting
2783 * the dmtree, as required, to reflect the new leaf value.
2784 * the combination of any buddies must already be done before
2785 * this is called.
2786 *
2787 * PARAMETERS:
2788 * tp - pointer to the tree to be adjusted.
2789 * leafno - the number of the leaf to be updated.
2790 * newval - the new value for the leaf.
2791 *
2792 * RETURN VALUES: none
2793 */
2794static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2795{
2796 int lp, pp, k;
2797 int max;
2798
2799 /* pick up the index of the leaf for this leafno.
2800 */
2801 lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2802
2803 /* is the current value the same as the old value ? if so,
2804 * there is nothing to do.
2805 */
2806 if (tp->dmt_stree[lp] == newval)
2807 return;
2808
2809 /* set the new value.
2810 */
2811 tp->dmt_stree[lp] = newval;
2812
2813 /* bubble the new value up the tree as required.
2814 */
2815 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2816 /* get the index of the first leaf of the 4 leaf
2817 * group containing the specified leaf (leafno).
2818 */
2819 lp = ((lp - 1) & ~0x03) + 1;
2820
2821 /* get the index of the parent of this 4 leaf group.
2822 */
2823 pp = (lp - 1) >> 2;
2824
2825 /* determine the maximum of the 4 leaves.
2826 */
2827 max = TREEMAX(&tp->dmt_stree[lp]);
2828
2829 /* if the maximum of the 4 is the same as the
2830 * parent's value, we're done.
2831 */
2832 if (tp->dmt_stree[pp] == max)
2833 break;
2834
2835 /* parent gets new value.
2836 */
2837 tp->dmt_stree[pp] = max;
2838
2839 /* parent becomes leaf for next go-round.
2840 */
2841 lp = pp;
2842 }
2843}
2844
2845
2846/*
2847 * NAME: dbFindLeaf()
2848 *
2849 * FUNCTION: search a dmtree_t for sufficient free blocks, returning
2850 * the index of a leaf describing the free blocks if
2851 * sufficient free blocks are found.
2852 *
2853 * the search starts at the top of the dmtree_t tree and
2854 * proceeds down the tree to the leftmost leaf with sufficient
2855 * free space.
2856 *
2857 * PARAMETERS:
2858 * tp - pointer to the tree to be searched.
2859 * l2nb - log2 number of free blocks to search for.
2860 * leafidx - return pointer to be set to the index of the leaf
2861 * describing at least l2nb free blocks if sufficient
2862 * free blocks are found.
2863 *
2864 * RETURN VALUES:
2865 * 0 - success
2866 * -ENOSPC - insufficient free blocks.
2867 */
2868static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2869{
2870 int ti, n = 0, k, x = 0;
2871
2872 /* first check the root of the tree to see if there is
2873 * sufficient free space.
2874 */
2875 if (l2nb > tp->dmt_stree[ROOT])
2876 return -ENOSPC;
2877
2878 /* sufficient free space available. now search down the tree
2879 * starting at the next level for the leftmost leaf that
2880 * describes sufficient free space.
2881 */
2882 for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2883 k > 0; k--, ti = ((ti + n) << 2) + 1) {
2884 /* search the four nodes at this level, starting from
2885 * the left.
2886 */
2887 for (x = ti, n = 0; n < 4; n++) {
2888 /* sufficient free space found. move to the next
2889 * level (or quit if this is the last level).
2890 */
2891 if (l2nb <= tp->dmt_stree[x + n])
2892 break;
2893 }
2894
2895 /* better have found something since the higher
2896 * levels of the tree said it was here.
2897 */
2898 assert(n < 4);
2899 }
2900
2901 /* set the return to the leftmost leaf describing sufficient
2902 * free space.
2903 */
2904 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2905
2906 return (0);
2907}
2908
2909
2910/*
2911 * NAME: dbFindBits()
2912 *
2913 * FUNCTION: find a specified number of binary buddy free bits within a
2914 * dmap bitmap word value.
2915 *
2916 * this routine searches the bitmap value for (1 << l2nb) free
2917 * bits at (1 << l2nb) alignments within the value.
2918 *
2919 * PARAMETERS:
2920 * word - dmap bitmap word value.
2921 * l2nb - number of free bits specified as a log2 number.
2922 *
2923 * RETURN VALUES:
2924 * starting bit number of free bits.
2925 */
2926static int dbFindBits(u32 word, int l2nb)
2927{
2928 int bitno, nb;
2929 u32 mask;
2930
2931 /* get the number of bits.
2932 */
2933 nb = 1 << l2nb;
2934 assert(nb <= DBWORD);
2935
2936 /* complement the word so we can use a mask (i.e. 0s represent
2937 * free bits) and compute the mask.
2938 */
2939 word = ~word;
2940 mask = ONES << (DBWORD - nb);
2941
2942 /* scan the word for nb free bits at nb alignments.
2943 */
2944 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2945 if ((mask & word) == mask)
2946 break;
2947 }
2948
2949 ASSERT(bitno < 32);
2950
2951 /* return the bit number.
2952 */
2953 return (bitno);
2954}
2955
2956
2957/*
2958 * NAME: dbMaxBud(u8 *cp)
2959 *
2960 * FUNCTION: determine the largest binary buddy string of free
2961 * bits within 32-bits of the map.
2962 *
2963 * PARAMETERS:
2964 * cp - pointer to the 32-bit value.
2965 *
2966 * RETURN VALUES:
2967 * largest binary buddy of free bits within a dmap word.
2968 */
2969static int dbMaxBud(u8 * cp)
2970{
2971 signed char tmp1, tmp2;
2972
2973 /* check if the wmap word is all free. if so, the
2974 * free buddy size is BUDMIN.
2975 */
2976 if (*((uint *) cp) == 0)
2977 return (BUDMIN);
2978
2979 /* check if the wmap word is half free. if so, the
2980 * free buddy size is BUDMIN-1.
2981 */
2982 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
2983 return (BUDMIN - 1);
2984
2985 /* not all free or half free. determine the free buddy
2986 * size thru table lookup using quarters of the wmap word.
2987 */
2988 tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
2989 tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
2990 return (max(tmp1, tmp2));
2991}
2992
2993
2994/*
2995 * NAME: cnttz(uint word)
2996 *
2997 * FUNCTION: determine the number of trailing zeros within a 32-bit
2998 * value.
2999 *
3000 * PARAMETERS:
3001 * value - 32-bit value to be examined.
3002 *
3003 * RETURN VALUES:
3004 * count of trailing zeros
3005 */
3006static int cnttz(u32 word)
3007{
3008 int n;
3009
3010 for (n = 0; n < 32; n++, word >>= 1) {
3011 if (word & 0x01)
3012 break;
3013 }
3014
3015 return (n);
3016}
3017
3018
3019/*
3020 * NAME: cntlz(u32 value)
3021 *
3022 * FUNCTION: determine the number of leading zeros within a 32-bit
3023 * value.
3024 *
3025 * PARAMETERS:
3026 * value - 32-bit value to be examined.
3027 *
3028 * RETURN VALUES:
3029 * count of leading zeros
3030 */
3031static int cntlz(u32 value)
3032{
3033 int n;
3034
3035 for (n = 0; n < 32; n++, value <<= 1) {
3036 if (value & HIGHORDER)
3037 break;
3038 }
3039 return (n);
3040}
3041
3042
3043/*
3044 * NAME: blkstol2(s64 nb)
3045 *
3046 * FUNCTION: convert a block count to its log2 value. if the block
3047 * count is not a l2 multiple, it is rounded up to the next
3048 * larger l2 multiple.
3049 *
3050 * PARAMETERS:
3051 * nb - number of blocks
3052 *
3053 * RETURN VALUES:
3054 * log2 number of blocks
3055 */
3056static int blkstol2(s64 nb)
3057{
3058 int l2nb;
3059 s64 mask; /* meant to be signed */
3060
3061 mask = (s64) 1 << (64 - 1);
3062
3063 /* count the leading bits.
3064 */
3065 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3066 /* leading bit found.
3067 */
3068 if (nb & mask) {
3069 /* determine the l2 value.
3070 */
3071 l2nb = (64 - 1) - l2nb;
3072
3073 /* check if we need to round up.
3074 */
3075 if (~mask & nb)
3076 l2nb++;
3077
3078 return (l2nb);
3079 }
3080 }
3081 assert(0);
3082 return 0; /* fix compiler warning */
3083}
3084
3085
3086/*
3087 * NAME: dbAllocBottomUp()
3088 *
3089 * FUNCTION: alloc the specified block range from the working block
3090 * allocation map.
3091 *
3092 * the blocks will be alloc from the working map one dmap
3093 * at a time.
3094 *
3095 * PARAMETERS:
3096 * ip - pointer to in-core inode;
3097 * blkno - starting block number to be freed.
3098 * nblocks - number of blocks to be freed.
3099 *
3100 * RETURN VALUES:
3101 * 0 - success
3102 * -EIO - i/o error
3103 */
3104int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3105{
3106 struct metapage *mp;
3107 struct dmap *dp;
3108 int nb, rc;
3109 s64 lblkno, rem;
3110 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3111 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3112
3113 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3114
3115 /* block to be allocated better be within the mapsize. */
3116 ASSERT(nblocks <= bmp->db_mapsize - blkno);
3117
3118 /*
3119 * allocate the blocks a dmap at a time.
3120 */
3121 mp = NULL;
3122 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3123 /* release previous dmap if any */
3124 if (mp) {
3125 write_metapage(mp);
3126 }
3127
3128 /* get the buffer for the current dmap. */
3129 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3130 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3131 if (mp == NULL) {
3132 IREAD_UNLOCK(ipbmap);
3133 return -EIO;
3134 }
3135 dp = (struct dmap *) mp->data;
3136
3137 /* determine the number of blocks to be allocated from
3138 * this dmap.
3139 */
3140 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3141
3142 /* allocate the blocks. */
3143 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3144 release_metapage(mp);
3145 IREAD_UNLOCK(ipbmap);
3146 return (rc);
3147 }
3148 }
3149
3150 /* write the last buffer. */
3151 write_metapage(mp);
3152
3153 IREAD_UNLOCK(ipbmap);
3154
3155 return (0);
3156}
3157
3158
3159static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3160 int nblocks)
3161{
3162 int rc;
3163 int dbitno, word, rembits, nb, nwords, wbitno, agno;
3164 s8 oldroot;
3165 struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3166
3167 /* save the current value of the root (i.e. maximum free string)
3168 * of the dmap tree.
3169 */
3170 oldroot = tp->stree[ROOT];
3171
3172 /* determine the bit number and word within the dmap of the
3173 * starting block.
3174 */
3175 dbitno = blkno & (BPERDMAP - 1);
3176 word = dbitno >> L2DBWORD;
3177
3178 /* block range better be within the dmap */
3179 assert(dbitno + nblocks <= BPERDMAP);
3180
3181 /* allocate the bits of the dmap's words corresponding to the block
3182 * range. not all bits of the first and last words may be contained
3183 * within the block range. if this is the case, we'll work against
3184 * those words (i.e. partial first and/or last) on an individual basis
3185 * (a single pass), allocating the bits of interest by hand and
3186 * updating the leaf corresponding to the dmap word. a single pass
3187 * will be used for all dmap words fully contained within the
3188 * specified range. within this pass, the bits of all fully contained
3189 * dmap words will be marked as free in a single shot and the leaves
3190 * will be updated. a single leaf may describe the free space of
3191 * multiple dmap words, so we may update only a subset of the actual
3192 * leaves corresponding to the dmap words of the block range.
3193 */
3194 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3195 /* determine the bit number within the word and
3196 * the number of bits within the word.
3197 */
3198 wbitno = dbitno & (DBWORD - 1);
3199 nb = min(rembits, DBWORD - wbitno);
3200
3201 /* check if only part of a word is to be allocated.
3202 */
3203 if (nb < DBWORD) {
3204 /* allocate (set to 1) the appropriate bits within
3205 * this dmap word.
3206 */
3207 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3208 >> wbitno);
3209
3210 word++;
3211 } else {
3212 /* one or more dmap words are fully contained
3213 * within the block range. determine how many
3214 * words and allocate (set to 1) the bits of these
3215 * words.
3216 */
3217 nwords = rembits >> L2DBWORD;
3218 memset(&dp->wmap[word], (int) ONES, nwords * 4);
3219
3220 /* determine how many bits */
3221 nb = nwords << L2DBWORD;
3222 word += nwords;
3223 }
3224 }
3225
3226 /* update the free count for this dmap */
3227 le32_add_cpu(&dp->nfree, -nblocks);
3228
3229 /* reconstruct summary tree */
3230 dbInitDmapTree(dp);
3231
3232 BMAP_LOCK(bmp);
3233
3234 /* if this allocation group is completely free,
3235 * update the highest active allocation group number
3236 * if this allocation group is the new max.
3237 */
3238 agno = blkno >> bmp->db_agl2size;
3239 if (agno > bmp->db_maxag)
3240 bmp->db_maxag = agno;
3241
3242 /* update the free count for the allocation group and map */
3243 bmp->db_agfree[agno] -= nblocks;
3244 bmp->db_nfree -= nblocks;
3245
3246 BMAP_UNLOCK(bmp);
3247
3248 /* if the root has not changed, done. */
3249 if (tp->stree[ROOT] == oldroot)
3250 return (0);
3251
3252 /* root changed. bubble the change up to the dmap control pages.
3253 * if the adjustment of the upper level control pages fails,
3254 * backout the bit allocation (thus making everything consistent).
3255 */
3256 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3257 dbFreeBits(bmp, dp, blkno, nblocks);
3258
3259 return (rc);
3260}
3261
3262
3263/*
3264 * NAME: dbExtendFS()
3265 *
3266 * FUNCTION: extend bmap from blkno for nblocks;
3267 * dbExtendFS() updates bmap ready for dbAllocBottomUp();
3268 *
3269 * L2
3270 * |
3271 * L1---------------------------------L1
3272 * | |
3273 * L0---------L0---------L0 L0---------L0---------L0
3274 * | | | | | |
3275 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
3276 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3277 *
3278 * <---old---><----------------------------extend----------------------->
3279 */
3280int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3281{
3282 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3283 int nbperpage = sbi->nbperpage;
3284 int i, i0 = true, j, j0 = true, k, n;
3285 s64 newsize;
3286 s64 p;
3287 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3288 struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3289 struct dmap *dp;
3290 s8 *l0leaf, *l1leaf, *l2leaf;
3291 struct bmap *bmp = sbi->bmap;
3292 int agno, l2agsize, oldl2agsize;
3293 s64 ag_rem;
3294
3295 newsize = blkno + nblocks;
3296
3297 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3298 (long long) blkno, (long long) nblocks, (long long) newsize);
3299
3300 /*
3301 * initialize bmap control page.
3302 *
3303 * all the data in bmap control page should exclude
3304 * the mkfs hidden dmap page.
3305 */
3306
3307 /* update mapsize */
3308 bmp->db_mapsize = newsize;
3309 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3310
3311 /* compute new AG size */
3312 l2agsize = dbGetL2AGSize(newsize);
3313 oldl2agsize = bmp->db_agl2size;
3314
3315 bmp->db_agl2size = l2agsize;
3316 bmp->db_agsize = 1 << l2agsize;
3317
3318 /* compute new number of AG */
3319 agno = bmp->db_numag;
3320 bmp->db_numag = newsize >> l2agsize;
3321 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3322
3323 /*
3324 * reconfigure db_agfree[]
3325 * from old AG configuration to new AG configuration;
3326 *
3327 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3328 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3329 * note: new AG size = old AG size * (2**x).
3330 */
3331 if (l2agsize == oldl2agsize)
3332 goto extend;
3333 k = 1 << (l2agsize - oldl2agsize);
3334 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
3335 for (i = 0, n = 0; i < agno; n++) {
3336 bmp->db_agfree[n] = 0; /* init collection point */
3337
3338 /* coalesce contiguous k AGs; */
3339 for (j = 0; j < k && i < agno; j++, i++) {
3340 /* merge AGi to AGn */
3341 bmp->db_agfree[n] += bmp->db_agfree[i];
3342 }
3343 }
3344 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
3345
3346 for (; n < MAXAG; n++)
3347 bmp->db_agfree[n] = 0;
3348
3349 /*
3350 * update highest active ag number
3351 */
3352
3353 bmp->db_maxag = bmp->db_maxag / k;
3354
3355 /*
3356 * extend bmap
3357 *
3358 * update bit maps and corresponding level control pages;
3359 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3360 */
3361 extend:
3362 /* get L2 page */
3363 p = BMAPBLKNO + nbperpage; /* L2 page */
3364 l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3365 if (!l2mp) {
3366 jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
3367 return -EIO;
3368 }
3369 l2dcp = (struct dmapctl *) l2mp->data;
3370
3371 /* compute start L1 */
3372 k = blkno >> L2MAXL1SIZE;
3373 l2leaf = l2dcp->stree + CTLLEAFIND + k;
3374 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
3375
3376 /*
3377 * extend each L1 in L2
3378 */
3379 for (; k < LPERCTL; k++, p += nbperpage) {
3380 /* get L1 page */
3381 if (j0) {
3382 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3383 l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3384 if (l1mp == NULL)
3385 goto errout;
3386 l1dcp = (struct dmapctl *) l1mp->data;
3387
3388 /* compute start L0 */
3389 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3390 l1leaf = l1dcp->stree + CTLLEAFIND + j;
3391 p = BLKTOL0(blkno, sbi->l2nbperpage);
3392 j0 = false;
3393 } else {
3394 /* assign/init L1 page */
3395 l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3396 if (l1mp == NULL)
3397 goto errout;
3398
3399 l1dcp = (struct dmapctl *) l1mp->data;
3400
3401 /* compute start L0 */
3402 j = 0;
3403 l1leaf = l1dcp->stree + CTLLEAFIND;
3404 p += nbperpage; /* 1st L0 of L1.k */
3405 }
3406
3407 /*
3408 * extend each L0 in L1
3409 */
3410 for (; j < LPERCTL; j++) {
3411 /* get L0 page */
3412 if (i0) {
3413 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3414
3415 l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3416 if (l0mp == NULL)
3417 goto errout;
3418 l0dcp = (struct dmapctl *) l0mp->data;
3419
3420 /* compute start dmap */
3421 i = (blkno & (MAXL0SIZE - 1)) >>
3422 L2BPERDMAP;
3423 l0leaf = l0dcp->stree + CTLLEAFIND + i;
3424 p = BLKTODMAP(blkno,
3425 sbi->l2nbperpage);
3426 i0 = false;
3427 } else {
3428 /* assign/init L0 page */
3429 l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3430 if (l0mp == NULL)
3431 goto errout;
3432
3433 l0dcp = (struct dmapctl *) l0mp->data;
3434
3435 /* compute start dmap */
3436 i = 0;
3437 l0leaf = l0dcp->stree + CTLLEAFIND;
3438 p += nbperpage; /* 1st dmap of L0.j */
3439 }
3440
3441 /*
3442 * extend each dmap in L0
3443 */
3444 for (; i < LPERCTL; i++) {
3445 /*
3446 * reconstruct the dmap page, and
3447 * initialize corresponding parent L0 leaf
3448 */
3449 if ((n = blkno & (BPERDMAP - 1))) {
3450 /* read in dmap page: */
3451 mp = read_metapage(ipbmap, p,
3452 PSIZE, 0);
3453 if (mp == NULL)
3454 goto errout;
3455 n = min(nblocks, (s64)BPERDMAP - n);
3456 } else {
3457 /* assign/init dmap page */
3458 mp = read_metapage(ipbmap, p,
3459 PSIZE, 0);
3460 if (mp == NULL)
3461 goto errout;
3462
3463 n = min(nblocks, (s64)BPERDMAP);
3464 }
3465
3466 dp = (struct dmap *) mp->data;
3467 *l0leaf = dbInitDmap(dp, blkno, n);
3468
3469 bmp->db_nfree += n;
3470 agno = le64_to_cpu(dp->start) >> l2agsize;
3471 bmp->db_agfree[agno] += n;
3472
3473 write_metapage(mp);
3474
3475 l0leaf++;
3476 p += nbperpage;
3477
3478 blkno += n;
3479 nblocks -= n;
3480 if (nblocks == 0)
3481 break;
3482 } /* for each dmap in a L0 */
3483
3484 /*
3485 * build current L0 page from its leaves, and
3486 * initialize corresponding parent L1 leaf
3487 */
3488 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3489 write_metapage(l0mp);
3490 l0mp = NULL;
3491
3492 if (nblocks)
3493 l1leaf++; /* continue for next L0 */
3494 else {
3495 /* more than 1 L0 ? */
3496 if (j > 0)
3497 break; /* build L1 page */
3498 else {
3499 /* summarize in global bmap page */
3500 bmp->db_maxfreebud = *l1leaf;
3501 release_metapage(l1mp);
3502 release_metapage(l2mp);
3503 goto finalize;
3504 }
3505 }
3506 } /* for each L0 in a L1 */
3507
3508 /*
3509 * build current L1 page from its leaves, and
3510 * initialize corresponding parent L2 leaf
3511 */
3512 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3513 write_metapage(l1mp);
3514 l1mp = NULL;
3515
3516 if (nblocks)
3517 l2leaf++; /* continue for next L1 */
3518 else {
3519 /* more than 1 L1 ? */
3520 if (k > 0)
3521 break; /* build L2 page */
3522 else {
3523 /* summarize in global bmap page */
3524 bmp->db_maxfreebud = *l2leaf;
3525 release_metapage(l2mp);
3526 goto finalize;
3527 }
3528 }
3529 } /* for each L1 in a L2 */
3530
3531 jfs_error(ipbmap->i_sb,
3532 "dbExtendFS: function has not returned as expected");
3533errout:
3534 if (l0mp)
3535 release_metapage(l0mp);
3536 if (l1mp)
3537 release_metapage(l1mp);
3538 release_metapage(l2mp);
3539 return -EIO;
3540
3541 /*
3542 * finalize bmap control page
3543 */
3544finalize:
3545
3546 return 0;
3547}
3548
3549
3550/*
3551 * dbFinalizeBmap()
3552 */
3553void dbFinalizeBmap(struct inode *ipbmap)
3554{
3555 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3556 int actags, inactags, l2nl;
3557 s64 ag_rem, actfree, inactfree, avgfree;
3558 int i, n;
3559
3560 /*
3561 * finalize bmap control page
3562 */
3563//finalize:
3564 /*
3565 * compute db_agpref: preferred ag to allocate from
3566 * (the leftmost ag with average free space in it);
3567 */
3568//agpref:
3569 /* get the number of active ags and inacitve ags */
3570 actags = bmp->db_maxag + 1;
3571 inactags = bmp->db_numag - actags;
3572 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
3573
3574 /* determine how many blocks are in the inactive allocation
3575 * groups. in doing this, we must account for the fact that
3576 * the rightmost group might be a partial group (i.e. file
3577 * system size is not a multiple of the group size).
3578 */
3579 inactfree = (inactags && ag_rem) ?
3580 ((inactags - 1) << bmp->db_agl2size) + ag_rem
3581 : inactags << bmp->db_agl2size;
3582
3583 /* determine how many free blocks are in the active
3584 * allocation groups plus the average number of free blocks
3585 * within the active ags.
3586 */
3587 actfree = bmp->db_nfree - inactfree;
3588 avgfree = (u32) actfree / (u32) actags;
3589
3590 /* if the preferred allocation group has not average free space.
3591 * re-establish the preferred group as the leftmost
3592 * group with average free space.
3593 */
3594 if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3595 for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3596 bmp->db_agpref++) {
3597 if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3598 break;
3599 }
3600 if (bmp->db_agpref >= bmp->db_numag) {
3601 jfs_error(ipbmap->i_sb,
3602 "cannot find ag with average freespace");
3603 }
3604 }
3605
3606 /*
3607 * compute db_aglevel, db_agheight, db_width, db_agstart:
3608 * an ag is covered in aglevel dmapctl summary tree,
3609 * at agheight level height (from leaf) with agwidth number of nodes
3610 * each, which starts at agstart index node of the smmary tree node
3611 * array;
3612 */
3613 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3614 l2nl =
3615 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3616 bmp->db_agheight = l2nl >> 1;
3617 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3618 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3619 i--) {
3620 bmp->db_agstart += n;
3621 n <<= 2;
3622 }
3623
3624}
3625
3626
3627/*
3628 * NAME: dbInitDmap()/ujfs_idmap_page()
3629 *
3630 * FUNCTION: initialize working/persistent bitmap of the dmap page
3631 * for the specified number of blocks:
3632 *
3633 * at entry, the bitmaps had been initialized as free (ZEROS);
3634 * The number of blocks will only account for the actually
3635 * existing blocks. Blocks which don't actually exist in
3636 * the aggregate will be marked as allocated (ONES);
3637 *
3638 * PARAMETERS:
3639 * dp - pointer to page of map
3640 * nblocks - number of blocks this page
3641 *
3642 * RETURNS: NONE
3643 */
3644static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3645{
3646 int blkno, w, b, r, nw, nb, i;
3647
3648 /* starting block number within the dmap */
3649 blkno = Blkno & (BPERDMAP - 1);
3650
3651 if (blkno == 0) {
3652 dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3653 dp->start = cpu_to_le64(Blkno);
3654
3655 if (nblocks == BPERDMAP) {
3656 memset(&dp->wmap[0], 0, LPERDMAP * 4);
3657 memset(&dp->pmap[0], 0, LPERDMAP * 4);
3658 goto initTree;
3659 }
3660 } else {
3661 le32_add_cpu(&dp->nblocks, nblocks);
3662 le32_add_cpu(&dp->nfree, nblocks);
3663 }
3664
3665 /* word number containing start block number */
3666 w = blkno >> L2DBWORD;
3667
3668 /*
3669 * free the bits corresponding to the block range (ZEROS):
3670 * note: not all bits of the first and last words may be contained
3671 * within the block range.
3672 */
3673 for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3674 /* number of bits preceding range to be freed in the word */
3675 b = blkno & (DBWORD - 1);
3676 /* number of bits to free in the word */
3677 nb = min(r, DBWORD - b);
3678
3679 /* is partial word to be freed ? */
3680 if (nb < DBWORD) {
3681 /* free (set to 0) from the bitmap word */
3682 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3683 >> b));
3684 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3685 >> b));
3686
3687 /* skip the word freed */
3688 w++;
3689 } else {
3690 /* free (set to 0) contiguous bitmap words */
3691 nw = r >> L2DBWORD;
3692 memset(&dp->wmap[w], 0, nw * 4);
3693 memset(&dp->pmap[w], 0, nw * 4);
3694
3695 /* skip the words freed */
3696 nb = nw << L2DBWORD;
3697 w += nw;
3698 }
3699 }
3700
3701 /*
3702 * mark bits following the range to be freed (non-existing
3703 * blocks) as allocated (ONES)
3704 */
3705
3706 if (blkno == BPERDMAP)
3707 goto initTree;
3708
3709 /* the first word beyond the end of existing blocks */
3710 w = blkno >> L2DBWORD;
3711
3712 /* does nblocks fall on a 32-bit boundary ? */
3713 b = blkno & (DBWORD - 1);
3714 if (b) {
3715 /* mark a partial word allocated */
3716 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3717 w++;
3718 }
3719
3720 /* set the rest of the words in the page to allocated (ONES) */
3721 for (i = w; i < LPERDMAP; i++)
3722 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3723
3724 /*
3725 * init tree
3726 */
3727 initTree:
3728 return (dbInitDmapTree(dp));
3729}
3730
3731
3732/*
3733 * NAME: dbInitDmapTree()/ujfs_complete_dmap()
3734 *
3735 * FUNCTION: initialize summary tree of the specified dmap:
3736 *
3737 * at entry, bitmap of the dmap has been initialized;
3738 *
3739 * PARAMETERS:
3740 * dp - dmap to complete
3741 * blkno - starting block number for this dmap
3742 * treemax - will be filled in with max free for this dmap
3743 *
3744 * RETURNS: max free string at the root of the tree
3745 */
3746static int dbInitDmapTree(struct dmap * dp)
3747{
3748 struct dmaptree *tp;
3749 s8 *cp;
3750 int i;
3751
3752 /* init fixed info of tree */
3753 tp = &dp->tree;
3754 tp->nleafs = cpu_to_le32(LPERDMAP);
3755 tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3756 tp->leafidx = cpu_to_le32(LEAFIND);
3757 tp->height = cpu_to_le32(4);
3758 tp->budmin = BUDMIN;
3759
3760 /* init each leaf from corresponding wmap word:
3761 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3762 * bitmap word are allocated.
3763 */
3764 cp = tp->stree + le32_to_cpu(tp->leafidx);
3765 for (i = 0; i < LPERDMAP; i++)
3766 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3767
3768 /* build the dmap's binary buddy summary tree */
3769 return (dbInitTree(tp));
3770}
3771
3772
3773/*
3774 * NAME: dbInitTree()/ujfs_adjtree()
3775 *
3776 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
3777 *
3778 * at entry, the leaves of the tree has been initialized
3779 * from corresponding bitmap word or root of summary tree
3780 * of the child control page;
3781 * configure binary buddy system at the leaf level, then
3782 * bubble up the values of the leaf nodes up the tree.
3783 *
3784 * PARAMETERS:
3785 * cp - Pointer to the root of the tree
3786 * l2leaves- Number of leaf nodes as a power of 2
3787 * l2min - Number of blocks that can be covered by a leaf
3788 * as a power of 2
3789 *
3790 * RETURNS: max free string at the root of the tree
3791 */
3792static int dbInitTree(struct dmaptree * dtp)
3793{
3794 int l2max, l2free, bsize, nextb, i;
3795 int child, parent, nparent;
3796 s8 *tp, *cp, *cp1;
3797
3798 tp = dtp->stree;
3799
3800 /* Determine the maximum free string possible for the leaves */
3801 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3802
3803 /*
3804 * configure the leaf levevl into binary buddy system
3805 *
3806 * Try to combine buddies starting with a buddy size of 1
3807 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3808 * can be combined if both buddies have a maximum free of l2min;
3809 * the combination will result in the left-most buddy leaf having
3810 * a maximum free of l2min+1.
3811 * After processing all buddies for a given size, process buddies
3812 * at the next higher buddy size (i.e. current size * 2) and
3813 * the next maximum free (current free + 1).
3814 * This continues until the maximum possible buddy combination
3815 * yields maximum free.
3816 */
3817 for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3818 l2free++, bsize = nextb) {
3819 /* get next buddy size == current buddy pair size */
3820 nextb = bsize << 1;
3821
3822 /* scan each adjacent buddy pair at current buddy size */
3823 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3824 i < le32_to_cpu(dtp->nleafs);
3825 i += nextb, cp += nextb) {
3826 /* coalesce if both adjacent buddies are max free */
3827 if (*cp == l2free && *(cp + bsize) == l2free) {
3828 *cp = l2free + 1; /* left take right */
3829 *(cp + bsize) = -1; /* right give left */
3830 }
3831 }
3832 }
3833
3834 /*
3835 * bubble summary information of leaves up the tree.
3836 *
3837 * Starting at the leaf node level, the four nodes described by
3838 * the higher level parent node are compared for a maximum free and
3839 * this maximum becomes the value of the parent node.
3840 * when all lower level nodes are processed in this fashion then
3841 * move up to the next level (parent becomes a lower level node) and
3842 * continue the process for that level.
3843 */
3844 for (child = le32_to_cpu(dtp->leafidx),
3845 nparent = le32_to_cpu(dtp->nleafs) >> 2;
3846 nparent > 0; nparent >>= 2, child = parent) {
3847 /* get index of 1st node of parent level */
3848 parent = (child - 1) >> 2;
3849
3850 /* set the value of the parent node as the maximum
3851 * of the four nodes of the current level.
3852 */
3853 for (i = 0, cp = tp + child, cp1 = tp + parent;
3854 i < nparent; i++, cp += 4, cp1++)
3855 *cp1 = TREEMAX(cp);
3856 }
3857
3858 return (*tp);
3859}
3860
3861
3862/*
3863 * dbInitDmapCtl()
3864 *
3865 * function: initialize dmapctl page
3866 */
3867static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3868{ /* start leaf index not covered by range */
3869 s8 *cp;
3870
3871 dcp->nleafs = cpu_to_le32(LPERCTL);
3872 dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3873 dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3874 dcp->height = cpu_to_le32(5);
3875 dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3876
3877 /*
3878 * initialize the leaves of current level that were not covered
3879 * by the specified input block range (i.e. the leaves have no
3880 * low level dmapctl or dmap).
3881 */
3882 cp = &dcp->stree[CTLLEAFIND + i];
3883 for (; i < LPERCTL; i++)
3884 *cp++ = NOFREE;
3885
3886 /* build the dmap's binary buddy summary tree */
3887 return (dbInitTree((struct dmaptree *) dcp));
3888}
3889
3890
3891/*
3892 * NAME: dbGetL2AGSize()/ujfs_getagl2size()
3893 *
3894 * FUNCTION: Determine log2(allocation group size) from aggregate size
3895 *
3896 * PARAMETERS:
3897 * nblocks - Number of blocks in aggregate
3898 *
3899 * RETURNS: log2(allocation group size) in aggregate blocks
3900 */
3901static int dbGetL2AGSize(s64 nblocks)
3902{
3903 s64 sz;
3904 s64 m;
3905 int l2sz;
3906
3907 if (nblocks < BPERDMAP * MAXAG)
3908 return (L2BPERDMAP);
3909
3910 /* round up aggregate size to power of 2 */
3911 m = ((u64) 1 << (64 - 1));
3912 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3913 if (m & nblocks)
3914 break;
3915 }
3916
3917 sz = (s64) 1 << l2sz;
3918 if (sz < nblocks)
3919 l2sz += 1;
3920
3921 /* agsize = roundupSize/max_number_of_ag */
3922 return (l2sz - L2MAXAG);
3923}
3924
3925
3926/*
3927 * NAME: dbMapFileSizeToMapSize()
3928 *
3929 * FUNCTION: compute number of blocks the block allocation map file
3930 * can cover from the map file size;
3931 *
3932 * RETURNS: Number of blocks which can be covered by this block map file;
3933 */
3934
3935/*
3936 * maximum number of map pages at each level including control pages
3937 */
3938#define MAXL0PAGES (1 + LPERCTL)
3939#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
3940#define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
3941
3942/*
3943 * convert number of map pages to the zero origin top dmapctl level
3944 */
3945#define BMAPPGTOLEV(npages) \
3946 (((npages) <= 3 + MAXL0PAGES) ? 0 : \
3947 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
3948
3949s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3950{
3951 struct super_block *sb = ipbmap->i_sb;
3952 s64 nblocks;
3953 s64 npages, ndmaps;
3954 int level, i;
3955 int complete, factor;
3956
3957 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
3958 npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
3959 level = BMAPPGTOLEV(npages);
3960
3961 /* At each level, accumulate the number of dmap pages covered by
3962 * the number of full child levels below it;
3963 * repeat for the last incomplete child level.
3964 */
3965 ndmaps = 0;
3966 npages--; /* skip the first global control page */
3967 /* skip higher level control pages above top level covered by map */
3968 npages -= (2 - level);
3969 npages--; /* skip top level's control page */
3970 for (i = level; i >= 0; i--) {
3971 factor =
3972 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
3973 complete = (u32) npages / factor;
3974 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
3975 ((i == 1) ? LPERCTL : 1));
3976
3977 /* pages in last/incomplete child */
3978 npages = (u32) npages % factor;
3979 /* skip incomplete child's level control page */
3980 npages--;
3981 }
3982
3983 /* convert the number of dmaps into the number of blocks
3984 * which can be covered by the dmaps;
3985 */
3986 nblocks = ndmaps << L2BPERDMAP;
3987
3988 return (nblocks);
3989}