1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) International Business Machines Corp., 2000-2004
4 * Portions Copyright (C) Tino Reichardt, 2012
5 */
6
7 #include <linux/fs.h>
8 #include <linux/slab.h>
9 #include "jfs_incore.h"
10 #include "jfs_superblock.h"
11 #include "jfs_dmap.h"
12 #include "jfs_imap.h"
13 #include "jfs_lock.h"
14 #include "jfs_metapage.h"
15 #include "jfs_debug.h"
16 #include "jfs_discard.h"
17
18 /*
19 * SERIALIZATION of the Block Allocation Map.
20 *
21 * the working state of the block allocation map is accessed in
22 * two directions:
23 *
24 * 1) allocation and free requests that start at the dmap
25 * level and move up through the dmap control pages (i.e.
26 * the vast majority of requests).
27 *
28 * 2) allocation requests that start at dmap control page
29 * level and work down towards the dmaps.
30 *
31 * the serialization scheme used here is as follows.
32 *
33 * requests which start at the bottom are serialized against each
34 * other through buffers and each requests holds onto its buffers
35 * as it works it way up from a single dmap to the required level
36 * of dmap control page.
37 * requests that start at the top are serialized against each other
38 * and request that start from the bottom by the multiple read/single
39 * write inode lock of the bmap inode. requests starting at the top
40 * take this lock in write mode while request starting at the bottom
41 * take the lock in read mode. a single top-down request may proceed
42 * exclusively while multiple bottoms-up requests may proceed
43 * simultaneously (under the protection of busy buffers).
44 *
45 * in addition to information found in dmaps and dmap control pages,
46 * the working state of the block allocation map also includes read/
47 * write information maintained in the bmap descriptor (i.e. total
48 * free block count, allocation group level free block counts).
49 * a single exclusive lock (BMAP_LOCK) is used to guard this information
50 * in the face of multiple-bottoms up requests.
51 * (lock ordering: IREAD_LOCK, BMAP_LOCK);
52 *
53 * accesses to the persistent state of the block allocation map (limited
54 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
55 */
56
57 #define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
58 #define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
59 #define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
60
61 /*
62 * forward references
63 */
64 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
65 int nblocks);
66 static void dbSplit(dmtree_t *tp, int leafno, int splitsz, int newval, bool is_ctl);
67 static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl);
68 static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl);
69 static void dbAdjTree(dmtree_t *tp, int leafno, int newval, bool is_ctl);
70 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
71 int level);
72 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
73 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
74 int nblocks);
75 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
76 int nblocks,
77 int l2nb, s64 * results);
78 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
79 int nblocks);
80 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
81 int l2nb,
82 s64 * results);
83 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
84 s64 * results);
85 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
86 s64 * results);
87 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
88 static int dbFindBits(u32 word, int l2nb);
89 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
90 static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl);
91 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
92 int nblocks);
93 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
94 int nblocks);
95 static int dbMaxBud(u8 * cp);
96 static int blkstol2(s64 nb);
97
98 static int cntlz(u32 value);
99 static int cnttz(u32 word);
100
101 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
102 int nblocks);
103 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
104 static int dbInitDmapTree(struct dmap * dp);
105 static int dbInitTree(struct dmaptree * dtp);
106 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
107 static int dbGetL2AGSize(s64 nblocks);
108
109 /*
110 * buddy table
111 *
112 * table used for determining buddy sizes within characters of
113 * dmap bitmap words. the characters themselves serve as indexes
114 * into the table, with the table elements yielding the maximum
115 * binary buddy of free bits within the character.
116 */
117 static const s8 budtab[256] = {
118 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
119 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
120 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
121 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
122 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
123 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
124 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
125 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
126 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
127 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
128 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
129 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
130 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
131 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
132 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
133 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
134 };
135
136 /*
137 * NAME: dbMount()
138 *
139 * FUNCTION: initializate the block allocation map.
140 *
141 * memory is allocated for the in-core bmap descriptor and
142 * the in-core descriptor is initialized from disk.
143 *
144 * PARAMETERS:
145 * ipbmap - pointer to in-core inode for the block map.
146 *
147 * RETURN VALUES:
148 * 0 - success
149 * -ENOMEM - insufficient memory
150 * -EIO - i/o error
151 * -EINVAL - wrong bmap data
152 */
dbMount(struct inode * ipbmap)153 int dbMount(struct inode *ipbmap)
154 {
155 struct bmap *bmp;
156 struct dbmap_disk *dbmp_le;
157 struct metapage *mp;
158 int i, err;
159
160 /*
161 * allocate/initialize the in-memory bmap descriptor
162 */
163 /* allocate memory for the in-memory bmap descriptor */
164 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
165 if (bmp == NULL)
166 return -ENOMEM;
167
168 /* read the on-disk bmap descriptor. */
169 mp = read_metapage(ipbmap,
170 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
171 PSIZE, 0);
172 if (mp == NULL) {
173 err = -EIO;
174 goto err_kfree_bmp;
175 }
176
177 /* copy the on-disk bmap descriptor to its in-memory version. */
178 dbmp_le = (struct dbmap_disk *) mp->data;
179 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
180 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
181 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
182 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
183 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
184 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
185 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
186 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
187 bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
188 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
189 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
190 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
191
192 if ((bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE) ||
193 (bmp->db_l2nbperpage < 0) ||
194 !bmp->db_numag || (bmp->db_numag > MAXAG) ||
195 (bmp->db_maxag >= MAXAG) || (bmp->db_maxag < 0) ||
196 (bmp->db_agpref >= MAXAG) || (bmp->db_agpref < 0) ||
197 !bmp->db_agwidth ||
198 (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG) ||
199 (bmp->db_agl2size < 0) ||
200 ((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) {
201 err = -EINVAL;
202 goto err_release_metapage;
203 }
204
205 for (i = 0; i < MAXAG; i++)
206 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
207 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
208 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
209
210 /* release the buffer. */
211 release_metapage(mp);
212
213 /* bind the bmap inode and the bmap descriptor to each other. */
214 bmp->db_ipbmap = ipbmap;
215 JFS_SBI(ipbmap->i_sb)->bmap = bmp;
216
217 memset(bmp->db_active, 0, sizeof(bmp->db_active));
218
219 /*
220 * allocate/initialize the bmap lock
221 */
222 BMAP_LOCK_INIT(bmp);
223
224 return (0);
225
226 err_release_metapage:
227 release_metapage(mp);
228 err_kfree_bmp:
229 kfree(bmp);
230 return err;
231 }
232
233
234 /*
235 * NAME: dbUnmount()
236 *
237 * FUNCTION: terminate the block allocation map in preparation for
238 * file system unmount.
239 *
240 * the in-core bmap descriptor is written to disk and
241 * the memory for this descriptor is freed.
242 *
243 * PARAMETERS:
244 * ipbmap - pointer to in-core inode for the block map.
245 *
246 * RETURN VALUES:
247 * 0 - success
248 * -EIO - i/o error
249 */
dbUnmount(struct inode * ipbmap,int mounterror)250 int dbUnmount(struct inode *ipbmap, int mounterror)
251 {
252 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
253
254 if (!(mounterror || isReadOnly(ipbmap)))
255 dbSync(ipbmap);
256
257 /*
258 * Invalidate the page cache buffers
259 */
260 truncate_inode_pages(ipbmap->i_mapping, 0);
261
262 /* free the memory for the in-memory bmap. */
263 kfree(bmp);
264 JFS_SBI(ipbmap->i_sb)->bmap = NULL;
265
266 return (0);
267 }
268
269 /*
270 * dbSync()
271 */
dbSync(struct inode * ipbmap)272 int dbSync(struct inode *ipbmap)
273 {
274 struct dbmap_disk *dbmp_le;
275 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
276 struct metapage *mp;
277 int i;
278
279 /*
280 * write bmap global control page
281 */
282 /* get the buffer for the on-disk bmap descriptor. */
283 mp = read_metapage(ipbmap,
284 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
285 PSIZE, 0);
286 if (mp == NULL) {
287 jfs_err("dbSync: read_metapage failed!");
288 return -EIO;
289 }
290 /* copy the in-memory version of the bmap to the on-disk version */
291 dbmp_le = (struct dbmap_disk *) mp->data;
292 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
293 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
294 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
295 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
296 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
297 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
298 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
299 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
300 dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
301 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
302 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
303 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
304 for (i = 0; i < MAXAG; i++)
305 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
306 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
307 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
308
309 /* write the buffer */
310 write_metapage(mp);
311
312 /*
313 * write out dirty pages of bmap
314 */
315 filemap_write_and_wait(ipbmap->i_mapping);
316
317 diWriteSpecial(ipbmap, 0);
318
319 return (0);
320 }
321
322 /*
323 * NAME: dbFree()
324 *
325 * FUNCTION: free the specified block range from the working block
326 * allocation map.
327 *
328 * the blocks will be free from the working map one dmap
329 * at a time.
330 *
331 * PARAMETERS:
332 * ip - pointer to in-core inode;
333 * blkno - starting block number to be freed.
334 * nblocks - number of blocks to be freed.
335 *
336 * RETURN VALUES:
337 * 0 - success
338 * -EIO - i/o error
339 */
dbFree(struct inode * ip,s64 blkno,s64 nblocks)340 int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
341 {
342 struct metapage *mp;
343 struct dmap *dp;
344 int nb, rc;
345 s64 lblkno, rem;
346 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
347 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
348 struct super_block *sb = ipbmap->i_sb;
349
350 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
351
352 /* block to be freed better be within the mapsize. */
353 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
354 IREAD_UNLOCK(ipbmap);
355 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
356 (unsigned long long) blkno,
357 (unsigned long long) nblocks);
358 jfs_error(ip->i_sb, "block to be freed is outside the map\n");
359 return -EIO;
360 }
361
362 /**
363 * TRIM the blocks, when mounted with discard option
364 */
365 if (JFS_SBI(sb)->flag & JFS_DISCARD)
366 if (JFS_SBI(sb)->minblks_trim <= nblocks)
367 jfs_issue_discard(ipbmap, blkno, nblocks);
368
369 /*
370 * free the blocks a dmap at a time.
371 */
372 mp = NULL;
373 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
374 /* release previous dmap if any */
375 if (mp) {
376 write_metapage(mp);
377 }
378
379 /* get the buffer for the current dmap. */
380 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
381 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
382 if (mp == NULL) {
383 IREAD_UNLOCK(ipbmap);
384 return -EIO;
385 }
386 dp = (struct dmap *) mp->data;
387
388 /* determine the number of blocks to be freed from
389 * this dmap.
390 */
391 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
392
393 /* free the blocks. */
394 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
395 jfs_error(ip->i_sb, "error in block map\n");
396 release_metapage(mp);
397 IREAD_UNLOCK(ipbmap);
398 return (rc);
399 }
400 }
401
402 /* write the last buffer. */
403 if (mp)
404 write_metapage(mp);
405
406 IREAD_UNLOCK(ipbmap);
407
408 return (0);
409 }
410
411
412 /*
413 * NAME: dbUpdatePMap()
414 *
415 * FUNCTION: update the allocation state (free or allocate) of the
416 * specified block range in the persistent block allocation map.
417 *
418 * the blocks will be updated in the persistent map one
419 * dmap at a time.
420 *
421 * PARAMETERS:
422 * ipbmap - pointer to in-core inode for the block map.
423 * free - 'true' if block range is to be freed from the persistent
424 * map; 'false' if it is to be allocated.
425 * blkno - starting block number of the range.
426 * nblocks - number of contiguous blocks in the range.
427 * tblk - transaction block;
428 *
429 * RETURN VALUES:
430 * 0 - success
431 * -EIO - i/o error
432 */
433 int
dbUpdatePMap(struct inode * ipbmap,int free,s64 blkno,s64 nblocks,struct tblock * tblk)434 dbUpdatePMap(struct inode *ipbmap,
435 int free, s64 blkno, s64 nblocks, struct tblock * tblk)
436 {
437 int nblks, dbitno, wbitno, rbits;
438 int word, nbits, nwords;
439 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
440 s64 lblkno, rem, lastlblkno;
441 u32 mask;
442 struct dmap *dp;
443 struct metapage *mp;
444 struct jfs_log *log;
445 int lsn, difft, diffp;
446 unsigned long flags;
447
448 /* the blocks better be within the mapsize. */
449 if (blkno + nblocks > bmp->db_mapsize) {
450 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
451 (unsigned long long) blkno,
452 (unsigned long long) nblocks);
453 jfs_error(ipbmap->i_sb, "blocks are outside the map\n");
454 return -EIO;
455 }
456
457 /* compute delta of transaction lsn from log syncpt */
458 lsn = tblk->lsn;
459 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
460 logdiff(difft, lsn, log);
461
462 /*
463 * update the block state a dmap at a time.
464 */
465 mp = NULL;
466 lastlblkno = 0;
467 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
468 /* get the buffer for the current dmap. */
469 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
470 if (lblkno != lastlblkno) {
471 if (mp) {
472 write_metapage(mp);
473 }
474
475 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
476 0);
477 if (mp == NULL)
478 return -EIO;
479 metapage_wait_for_io(mp);
480 }
481 dp = (struct dmap *) mp->data;
482
483 /* determine the bit number and word within the dmap of
484 * the starting block. also determine how many blocks
485 * are to be updated within this dmap.
486 */
487 dbitno = blkno & (BPERDMAP - 1);
488 word = dbitno >> L2DBWORD;
489 nblks = min(rem, (s64)BPERDMAP - dbitno);
490
491 /* update the bits of the dmap words. the first and last
492 * words may only have a subset of their bits updated. if
493 * this is the case, we'll work against that word (i.e.
494 * partial first and/or last) only in a single pass. a
495 * single pass will also be used to update all words that
496 * are to have all their bits updated.
497 */
498 for (rbits = nblks; rbits > 0;
499 rbits -= nbits, dbitno += nbits) {
500 /* determine the bit number within the word and
501 * the number of bits within the word.
502 */
503 wbitno = dbitno & (DBWORD - 1);
504 nbits = min(rbits, DBWORD - wbitno);
505
506 /* check if only part of the word is to be updated. */
507 if (nbits < DBWORD) {
508 /* update (free or allocate) the bits
509 * in this word.
510 */
511 mask =
512 (ONES << (DBWORD - nbits) >> wbitno);
513 if (free)
514 dp->pmap[word] &=
515 cpu_to_le32(~mask);
516 else
517 dp->pmap[word] |=
518 cpu_to_le32(mask);
519
520 word += 1;
521 } else {
522 /* one or more words are to have all
523 * their bits updated. determine how
524 * many words and how many bits.
525 */
526 nwords = rbits >> L2DBWORD;
527 nbits = nwords << L2DBWORD;
528
529 /* update (free or allocate) the bits
530 * in these words.
531 */
532 if (free)
533 memset(&dp->pmap[word], 0,
534 nwords * 4);
535 else
536 memset(&dp->pmap[word], (int) ONES,
537 nwords * 4);
538
539 word += nwords;
540 }
541 }
542
543 /*
544 * update dmap lsn
545 */
546 if (lblkno == lastlblkno)
547 continue;
548
549 lastlblkno = lblkno;
550
551 LOGSYNC_LOCK(log, flags);
552 if (mp->lsn != 0) {
553 /* inherit older/smaller lsn */
554 logdiff(diffp, mp->lsn, log);
555 if (difft < diffp) {
556 mp->lsn = lsn;
557
558 /* move bp after tblock in logsync list */
559 list_move(&mp->synclist, &tblk->synclist);
560 }
561
562 /* inherit younger/larger clsn */
563 logdiff(difft, tblk->clsn, log);
564 logdiff(diffp, mp->clsn, log);
565 if (difft > diffp)
566 mp->clsn = tblk->clsn;
567 } else {
568 mp->log = log;
569 mp->lsn = lsn;
570
571 /* insert bp after tblock in logsync list */
572 log->count++;
573 list_add(&mp->synclist, &tblk->synclist);
574
575 mp->clsn = tblk->clsn;
576 }
577 LOGSYNC_UNLOCK(log, flags);
578 }
579
580 /* write the last buffer. */
581 if (mp) {
582 write_metapage(mp);
583 }
584
585 return (0);
586 }
587
588
589 /*
590 * NAME: dbNextAG()
591 *
592 * FUNCTION: find the preferred allocation group for new allocations.
593 *
594 * Within the allocation groups, we maintain a preferred
595 * allocation group which consists of a group with at least
596 * average free space. It is the preferred group that we target
597 * new inode allocation towards. The tie-in between inode
598 * allocation and block allocation occurs as we allocate the
599 * first (data) block of an inode and specify the inode (block)
600 * as the allocation hint for this block.
601 *
602 * We try to avoid having more than one open file growing in
603 * an allocation group, as this will lead to fragmentation.
604 * This differs from the old OS/2 method of trying to keep
605 * empty ags around for large allocations.
606 *
607 * PARAMETERS:
608 * ipbmap - pointer to in-core inode for the block map.
609 *
610 * RETURN VALUES:
611 * the preferred allocation group number.
612 */
dbNextAG(struct inode * ipbmap)613 int dbNextAG(struct inode *ipbmap)
614 {
615 s64 avgfree;
616 int agpref;
617 s64 hwm = 0;
618 int i;
619 int next_best = -1;
620 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
621
622 BMAP_LOCK(bmp);
623
624 /* determine the average number of free blocks within the ags. */
625 avgfree = (u32)bmp->db_nfree / bmp->db_numag;
626
627 /*
628 * if the current preferred ag does not have an active allocator
629 * and has at least average freespace, return it
630 */
631 agpref = bmp->db_agpref;
632 if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
633 (bmp->db_agfree[agpref] >= avgfree))
634 goto unlock;
635
636 /* From the last preferred ag, find the next one with at least
637 * average free space.
638 */
639 for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
640 if (agpref >= bmp->db_numag)
641 agpref = 0;
642
643 if (atomic_read(&bmp->db_active[agpref]))
644 /* open file is currently growing in this ag */
645 continue;
646 if (bmp->db_agfree[agpref] >= avgfree) {
647 /* Return this one */
648 bmp->db_agpref = agpref;
649 goto unlock;
650 } else if (bmp->db_agfree[agpref] > hwm) {
651 /* Less than avg. freespace, but best so far */
652 hwm = bmp->db_agfree[agpref];
653 next_best = agpref;
654 }
655 }
656
657 /*
658 * If no inactive ag was found with average freespace, use the
659 * next best
660 */
661 if (next_best != -1)
662 bmp->db_agpref = next_best;
663 /* else leave db_agpref unchanged */
664 unlock:
665 BMAP_UNLOCK(bmp);
666
667 /* return the preferred group.
668 */
669 return (bmp->db_agpref);
670 }
671
672 /*
673 * NAME: dbAlloc()
674 *
675 * FUNCTION: attempt to allocate a specified number of contiguous free
676 * blocks from the working allocation block map.
677 *
678 * the block allocation policy uses hints and a multi-step
679 * approach.
680 *
681 * for allocation requests smaller than the number of blocks
682 * per dmap, we first try to allocate the new blocks
683 * immediately following the hint. if these blocks are not
684 * available, we try to allocate blocks near the hint. if
685 * no blocks near the hint are available, we next try to
686 * allocate within the same dmap as contains the hint.
687 *
688 * if no blocks are available in the dmap or the allocation
689 * request is larger than the dmap size, we try to allocate
690 * within the same allocation group as contains the hint. if
691 * this does not succeed, we finally try to allocate anywhere
692 * within the aggregate.
693 *
694 * we also try to allocate anywhere within the aggregate
695 * for allocation requests larger than the allocation group
696 * size or requests that specify no hint value.
697 *
698 * PARAMETERS:
699 * ip - pointer to in-core inode;
700 * hint - allocation hint.
701 * nblocks - number of contiguous blocks in the range.
702 * results - on successful return, set to the starting block number
703 * of the newly allocated contiguous range.
704 *
705 * RETURN VALUES:
706 * 0 - success
707 * -ENOSPC - insufficient disk resources
708 * -EIO - i/o error
709 */
dbAlloc(struct inode * ip,s64 hint,s64 nblocks,s64 * results)710 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
711 {
712 int rc, agno;
713 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
714 struct bmap *bmp;
715 struct metapage *mp;
716 s64 lblkno, blkno;
717 struct dmap *dp;
718 int l2nb;
719 s64 mapSize;
720 int writers;
721
722 /* assert that nblocks is valid */
723 assert(nblocks > 0);
724
725 /* get the log2 number of blocks to be allocated.
726 * if the number of blocks is not a log2 multiple,
727 * it will be rounded up to the next log2 multiple.
728 */
729 l2nb = BLKSTOL2(nblocks);
730
731 bmp = JFS_SBI(ip->i_sb)->bmap;
732
733 mapSize = bmp->db_mapsize;
734
735 /* the hint should be within the map */
736 if (hint >= mapSize) {
737 jfs_error(ip->i_sb, "the hint is outside the map\n");
738 return -EIO;
739 }
740
741 /* if the number of blocks to be allocated is greater than the
742 * allocation group size, try to allocate anywhere.
743 */
744 if (l2nb > bmp->db_agl2size) {
745 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
746
747 rc = dbAllocAny(bmp, nblocks, l2nb, results);
748
749 goto write_unlock;
750 }
751
752 /*
753 * If no hint, let dbNextAG recommend an allocation group
754 */
755 if (hint == 0)
756 goto pref_ag;
757
758 /* we would like to allocate close to the hint. adjust the
759 * hint to the block following the hint since the allocators
760 * will start looking for free space starting at this point.
761 */
762 blkno = hint + 1;
763
764 if (blkno >= bmp->db_mapsize)
765 goto pref_ag;
766
767 agno = blkno >> bmp->db_agl2size;
768
769 /* check if blkno crosses over into a new allocation group.
770 * if so, check if we should allow allocations within this
771 * allocation group.
772 */
773 if ((blkno & (bmp->db_agsize - 1)) == 0)
774 /* check if the AG is currently being written to.
775 * if so, call dbNextAG() to find a non-busy
776 * AG with sufficient free space.
777 */
778 if (atomic_read(&bmp->db_active[agno]))
779 goto pref_ag;
780
781 /* check if the allocation request size can be satisfied from a
782 * single dmap. if so, try to allocate from the dmap containing
783 * the hint using a tiered strategy.
784 */
785 if (nblocks <= BPERDMAP) {
786 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
787
788 /* get the buffer for the dmap containing the hint.
789 */
790 rc = -EIO;
791 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
792 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
793 if (mp == NULL)
794 goto read_unlock;
795
796 dp = (struct dmap *) mp->data;
797
798 /* first, try to satisfy the allocation request with the
799 * blocks beginning at the hint.
800 */
801 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
802 != -ENOSPC) {
803 if (rc == 0) {
804 *results = blkno;
805 mark_metapage_dirty(mp);
806 }
807
808 release_metapage(mp);
809 goto read_unlock;
810 }
811
812 writers = atomic_read(&bmp->db_active[agno]);
813 if ((writers > 1) ||
814 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
815 /*
816 * Someone else is writing in this allocation
817 * group. To avoid fragmenting, try another ag
818 */
819 release_metapage(mp);
820 IREAD_UNLOCK(ipbmap);
821 goto pref_ag;
822 }
823
824 /* next, try to satisfy the allocation request with blocks
825 * near the hint.
826 */
827 if ((rc =
828 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
829 != -ENOSPC) {
830 if (rc == 0)
831 mark_metapage_dirty(mp);
832
833 release_metapage(mp);
834 goto read_unlock;
835 }
836
837 /* try to satisfy the allocation request with blocks within
838 * the same dmap as the hint.
839 */
840 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
841 != -ENOSPC) {
842 if (rc == 0)
843 mark_metapage_dirty(mp);
844
845 release_metapage(mp);
846 goto read_unlock;
847 }
848
849 release_metapage(mp);
850 IREAD_UNLOCK(ipbmap);
851 }
852
853 /* try to satisfy the allocation request with blocks within
854 * the same allocation group as the hint.
855 */
856 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
857 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
858 goto write_unlock;
859
860 IWRITE_UNLOCK(ipbmap);
861
862
863 pref_ag:
864 /*
865 * Let dbNextAG recommend a preferred allocation group
866 */
867 agno = dbNextAG(ipbmap);
868 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
869
870 /* Try to allocate within this allocation group. if that fails, try to
871 * allocate anywhere in the map.
872 */
873 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
874 rc = dbAllocAny(bmp, nblocks, l2nb, results);
875
876 write_unlock:
877 IWRITE_UNLOCK(ipbmap);
878
879 return (rc);
880
881 read_unlock:
882 IREAD_UNLOCK(ipbmap);
883
884 return (rc);
885 }
886
887 /*
888 * NAME: dbReAlloc()
889 *
890 * FUNCTION: attempt to extend a current allocation by a specified
891 * number of blocks.
892 *
893 * this routine attempts to satisfy the allocation request
894 * by first trying to extend the existing allocation in
895 * place by allocating the additional blocks as the blocks
896 * immediately following the current allocation. if these
897 * blocks are not available, this routine will attempt to
898 * allocate a new set of contiguous blocks large enough
899 * to cover the existing allocation plus the additional
900 * number of blocks required.
901 *
902 * PARAMETERS:
903 * ip - pointer to in-core inode requiring allocation.
904 * blkno - starting block of the current allocation.
905 * nblocks - number of contiguous blocks within the current
906 * allocation.
907 * addnblocks - number of blocks to add to the allocation.
908 * results - on successful return, set to the starting block number
909 * of the existing allocation if the existing allocation
910 * was extended in place or to a newly allocated contiguous
911 * range if the existing allocation could not be extended
912 * in place.
913 *
914 * RETURN VALUES:
915 * 0 - success
916 * -ENOSPC - insufficient disk resources
917 * -EIO - i/o error
918 */
919 int
dbReAlloc(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks,s64 * results)920 dbReAlloc(struct inode *ip,
921 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
922 {
923 int rc;
924
925 /* try to extend the allocation in place.
926 */
927 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
928 *results = blkno;
929 return (0);
930 } else {
931 if (rc != -ENOSPC)
932 return (rc);
933 }
934
935 /* could not extend the allocation in place, so allocate a
936 * new set of blocks for the entire request (i.e. try to get
937 * a range of contiguous blocks large enough to cover the
938 * existing allocation plus the additional blocks.)
939 */
940 return (dbAlloc
941 (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
942 }
943
944
945 /*
946 * NAME: dbExtend()
947 *
948 * FUNCTION: attempt to extend a current allocation by a specified
949 * number of blocks.
950 *
951 * this routine attempts to satisfy the allocation request
952 * by first trying to extend the existing allocation in
953 * place by allocating the additional blocks as the blocks
954 * immediately following the current allocation.
955 *
956 * PARAMETERS:
957 * ip - pointer to in-core inode requiring allocation.
958 * blkno - starting block of the current allocation.
959 * nblocks - number of contiguous blocks within the current
960 * allocation.
961 * addnblocks - number of blocks to add to the allocation.
962 *
963 * RETURN VALUES:
964 * 0 - success
965 * -ENOSPC - insufficient disk resources
966 * -EIO - i/o error
967 */
dbExtend(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks)968 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
969 {
970 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
971 s64 lblkno, lastblkno, extblkno;
972 uint rel_block;
973 struct metapage *mp;
974 struct dmap *dp;
975 int rc;
976 struct inode *ipbmap = sbi->ipbmap;
977 struct bmap *bmp;
978
979 /*
980 * We don't want a non-aligned extent to cross a page boundary
981 */
982 if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
983 (rel_block + nblocks + addnblocks > sbi->nbperpage))
984 return -ENOSPC;
985
986 /* get the last block of the current allocation */
987 lastblkno = blkno + nblocks - 1;
988
989 /* determine the block number of the block following
990 * the existing allocation.
991 */
992 extblkno = lastblkno + 1;
993
994 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
995
996 /* better be within the file system */
997 bmp = sbi->bmap;
998 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
999 IREAD_UNLOCK(ipbmap);
1000 jfs_error(ip->i_sb, "the block is outside the filesystem\n");
1001 return -EIO;
1002 }
1003
1004 /* we'll attempt to extend the current allocation in place by
1005 * allocating the additional blocks as the blocks immediately
1006 * following the current allocation. we only try to extend the
1007 * current allocation in place if the number of additional blocks
1008 * can fit into a dmap, the last block of the current allocation
1009 * is not the last block of the file system, and the start of the
1010 * inplace extension is not on an allocation group boundary.
1011 */
1012 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1013 (extblkno & (bmp->db_agsize - 1)) == 0) {
1014 IREAD_UNLOCK(ipbmap);
1015 return -ENOSPC;
1016 }
1017
1018 /* get the buffer for the dmap containing the first block
1019 * of the extension.
1020 */
1021 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1022 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1023 if (mp == NULL) {
1024 IREAD_UNLOCK(ipbmap);
1025 return -EIO;
1026 }
1027
1028 dp = (struct dmap *) mp->data;
1029
1030 /* try to allocate the blocks immediately following the
1031 * current allocation.
1032 */
1033 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1034
1035 IREAD_UNLOCK(ipbmap);
1036
1037 /* were we successful ? */
1038 if (rc == 0)
1039 write_metapage(mp);
1040 else
1041 /* we were not successful */
1042 release_metapage(mp);
1043
1044 return (rc);
1045 }
1046
1047
1048 /*
1049 * NAME: dbAllocNext()
1050 *
1051 * FUNCTION: attempt to allocate the blocks of the specified block
1052 * range within a dmap.
1053 *
1054 * PARAMETERS:
1055 * bmp - pointer to bmap descriptor
1056 * dp - pointer to dmap.
1057 * blkno - starting block number of the range.
1058 * nblocks - number of contiguous free blocks of the range.
1059 *
1060 * RETURN VALUES:
1061 * 0 - success
1062 * -ENOSPC - insufficient disk resources
1063 * -EIO - i/o error
1064 *
1065 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1066 */
dbAllocNext(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)1067 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1068 int nblocks)
1069 {
1070 int dbitno, word, rembits, nb, nwords, wbitno, nw;
1071 int l2size;
1072 s8 *leaf;
1073 u32 mask;
1074
1075 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1076 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1077 return -EIO;
1078 }
1079
1080 /* pick up a pointer to the leaves of the dmap tree.
1081 */
1082 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1083
1084 /* determine the bit number and word within the dmap of the
1085 * starting block.
1086 */
1087 dbitno = blkno & (BPERDMAP - 1);
1088 word = dbitno >> L2DBWORD;
1089
1090 /* check if the specified block range is contained within
1091 * this dmap.
1092 */
1093 if (dbitno + nblocks > BPERDMAP)
1094 return -ENOSPC;
1095
1096 /* check if the starting leaf indicates that anything
1097 * is free.
1098 */
1099 if (leaf[word] == NOFREE)
1100 return -ENOSPC;
1101
1102 /* check the dmaps words corresponding to block range to see
1103 * if the block range is free. not all bits of the first and
1104 * last words may be contained within the block range. if this
1105 * is the case, we'll work against those words (i.e. partial first
1106 * and/or last) on an individual basis (a single pass) and examine
1107 * the actual bits to determine if they are free. a single pass
1108 * will be used for all dmap words fully contained within the
1109 * specified range. within this pass, the leaves of the dmap
1110 * tree will be examined to determine if the blocks are free. a
1111 * single leaf may describe the free space of multiple dmap
1112 * words, so we may visit only a subset of the actual leaves
1113 * corresponding to the dmap words of the block range.
1114 */
1115 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1116 /* determine the bit number within the word and
1117 * the number of bits within the word.
1118 */
1119 wbitno = dbitno & (DBWORD - 1);
1120 nb = min(rembits, DBWORD - wbitno);
1121
1122 /* check if only part of the word is to be examined.
1123 */
1124 if (nb < DBWORD) {
1125 /* check if the bits are free.
1126 */
1127 mask = (ONES << (DBWORD - nb) >> wbitno);
1128 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1129 return -ENOSPC;
1130
1131 word += 1;
1132 } else {
1133 /* one or more dmap words are fully contained
1134 * within the block range. determine how many
1135 * words and how many bits.
1136 */
1137 nwords = rembits >> L2DBWORD;
1138 nb = nwords << L2DBWORD;
1139
1140 /* now examine the appropriate leaves to determine
1141 * if the blocks are free.
1142 */
1143 while (nwords > 0) {
1144 /* does the leaf describe any free space ?
1145 */
1146 if (leaf[word] < BUDMIN)
1147 return -ENOSPC;
1148
1149 /* determine the l2 number of bits provided
1150 * by this leaf.
1151 */
1152 l2size =
1153 min_t(int, leaf[word], NLSTOL2BSZ(nwords));
1154
1155 /* determine how many words were handled.
1156 */
1157 nw = BUDSIZE(l2size, BUDMIN);
1158
1159 nwords -= nw;
1160 word += nw;
1161 }
1162 }
1163 }
1164
1165 /* allocate the blocks.
1166 */
1167 return (dbAllocDmap(bmp, dp, blkno, nblocks));
1168 }
1169
1170
1171 /*
1172 * NAME: dbAllocNear()
1173 *
1174 * FUNCTION: attempt to allocate a number of contiguous free blocks near
1175 * a specified block (hint) within a dmap.
1176 *
1177 * starting with the dmap leaf that covers the hint, we'll
1178 * check the next four contiguous leaves for sufficient free
1179 * space. if sufficient free space is found, we'll allocate
1180 * the desired free space.
1181 *
1182 * PARAMETERS:
1183 * bmp - pointer to bmap descriptor
1184 * dp - pointer to dmap.
1185 * blkno - block number to allocate near.
1186 * nblocks - actual number of contiguous free blocks desired.
1187 * l2nb - log2 number of contiguous free blocks desired.
1188 * results - on successful return, set to the starting block number
1189 * of the newly allocated range.
1190 *
1191 * RETURN VALUES:
1192 * 0 - success
1193 * -ENOSPC - insufficient disk resources
1194 * -EIO - i/o error
1195 *
1196 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1197 */
1198 static int
dbAllocNear(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks,int l2nb,s64 * results)1199 dbAllocNear(struct bmap * bmp,
1200 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1201 {
1202 int word, lword, rc;
1203 s8 *leaf;
1204
1205 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1206 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1207 return -EIO;
1208 }
1209
1210 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1211
1212 /* determine the word within the dmap that holds the hint
1213 * (i.e. blkno). also, determine the last word in the dmap
1214 * that we'll include in our examination.
1215 */
1216 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1217 lword = min(word + 4, LPERDMAP);
1218
1219 /* examine the leaves for sufficient free space.
1220 */
1221 for (; word < lword; word++) {
1222 /* does the leaf describe sufficient free space ?
1223 */
1224 if (leaf[word] < l2nb)
1225 continue;
1226
1227 /* determine the block number within the file system
1228 * of the first block described by this dmap word.
1229 */
1230 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1231
1232 /* if not all bits of the dmap word are free, get the
1233 * starting bit number within the dmap word of the required
1234 * string of free bits and adjust the block number with the
1235 * value.
1236 */
1237 if (leaf[word] < BUDMIN)
1238 blkno +=
1239 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1240
1241 /* allocate the blocks.
1242 */
1243 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1244 *results = blkno;
1245
1246 return (rc);
1247 }
1248
1249 return -ENOSPC;
1250 }
1251
1252
1253 /*
1254 * NAME: dbAllocAG()
1255 *
1256 * FUNCTION: attempt to allocate the specified number of contiguous
1257 * free blocks within the specified allocation group.
1258 *
1259 * unless the allocation group size is equal to the number
1260 * of blocks per dmap, the dmap control pages will be used to
1261 * find the required free space, if available. we start the
1262 * search at the highest dmap control page level which
1263 * distinctly describes the allocation group's free space
1264 * (i.e. the highest level at which the allocation group's
1265 * free space is not mixed in with that of any other group).
1266 * in addition, we start the search within this level at a
1267 * height of the dmapctl dmtree at which the nodes distinctly
1268 * describe the allocation group's free space. at this height,
1269 * the allocation group's free space may be represented by 1
1270 * or two sub-trees, depending on the allocation group size.
1271 * we search the top nodes of these subtrees left to right for
1272 * sufficient free space. if sufficient free space is found,
1273 * the subtree is searched to find the leftmost leaf that
1274 * has free space. once we have made it to the leaf, we
1275 * move the search to the next lower level dmap control page
1276 * corresponding to this leaf. we continue down the dmap control
1277 * pages until we find the dmap that contains or starts the
1278 * sufficient free space and we allocate at this dmap.
1279 *
1280 * if the allocation group size is equal to the dmap size,
1281 * we'll start at the dmap corresponding to the allocation
1282 * group and attempt the allocation at this level.
1283 *
1284 * the dmap control page search is also not performed if the
1285 * allocation group is completely free and we go to the first
1286 * dmap of the allocation group to do the allocation. this is
1287 * done because the allocation group may be part (not the first
1288 * part) of a larger binary buddy system, causing the dmap
1289 * control pages to indicate no free space (NOFREE) within
1290 * the allocation group.
1291 *
1292 * PARAMETERS:
1293 * bmp - pointer to bmap descriptor
1294 * agno - allocation group number.
1295 * nblocks - actual number of contiguous free blocks desired.
1296 * l2nb - log2 number of contiguous free blocks desired.
1297 * results - on successful return, set to the starting block number
1298 * of the newly allocated range.
1299 *
1300 * RETURN VALUES:
1301 * 0 - success
1302 * -ENOSPC - insufficient disk resources
1303 * -EIO - i/o error
1304 *
1305 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1306 */
1307 static int
dbAllocAG(struct bmap * bmp,int agno,s64 nblocks,int l2nb,s64 * results)1308 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1309 {
1310 struct metapage *mp;
1311 struct dmapctl *dcp;
1312 int rc, ti, i, k, m, n, agperlev;
1313 s64 blkno, lblkno;
1314 int budmin;
1315
1316 /* allocation request should not be for more than the
1317 * allocation group size.
1318 */
1319 if (l2nb > bmp->db_agl2size) {
1320 jfs_error(bmp->db_ipbmap->i_sb,
1321 "allocation request is larger than the allocation group size\n");
1322 return -EIO;
1323 }
1324
1325 /* determine the starting block number of the allocation
1326 * group.
1327 */
1328 blkno = (s64) agno << bmp->db_agl2size;
1329
1330 /* check if the allocation group size is the minimum allocation
1331 * group size or if the allocation group is completely free. if
1332 * the allocation group size is the minimum size of BPERDMAP (i.e.
1333 * 1 dmap), there is no need to search the dmap control page (below)
1334 * that fully describes the allocation group since the allocation
1335 * group is already fully described by a dmap. in this case, we
1336 * just call dbAllocCtl() to search the dmap tree and allocate the
1337 * required space if available.
1338 *
1339 * if the allocation group is completely free, dbAllocCtl() is
1340 * also called to allocate the required space. this is done for
1341 * two reasons. first, it makes no sense searching the dmap control
1342 * pages for free space when we know that free space exists. second,
1343 * the dmap control pages may indicate that the allocation group
1344 * has no free space if the allocation group is part (not the first
1345 * part) of a larger binary buddy system.
1346 */
1347 if (bmp->db_agsize == BPERDMAP
1348 || bmp->db_agfree[agno] == bmp->db_agsize) {
1349 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1350 if ((rc == -ENOSPC) &&
1351 (bmp->db_agfree[agno] == bmp->db_agsize)) {
1352 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1353 (unsigned long long) blkno,
1354 (unsigned long long) nblocks);
1355 jfs_error(bmp->db_ipbmap->i_sb,
1356 "dbAllocCtl failed in free AG\n");
1357 }
1358 return (rc);
1359 }
1360
1361 /* the buffer for the dmap control page that fully describes the
1362 * allocation group.
1363 */
1364 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1365 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1366 if (mp == NULL)
1367 return -EIO;
1368 dcp = (struct dmapctl *) mp->data;
1369 budmin = dcp->budmin;
1370
1371 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1372 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
1373 release_metapage(mp);
1374 return -EIO;
1375 }
1376
1377 /* search the subtree(s) of the dmap control page that describes
1378 * the allocation group, looking for sufficient free space. to begin,
1379 * determine how many allocation groups are represented in a dmap
1380 * control page at the control page level (i.e. L0, L1, L2) that
1381 * fully describes an allocation group. next, determine the starting
1382 * tree index of this allocation group within the control page.
1383 */
1384 agperlev =
1385 (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1386 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1387
1388 /* dmap control page trees fan-out by 4 and a single allocation
1389 * group may be described by 1 or 2 subtrees within the ag level
1390 * dmap control page, depending upon the ag size. examine the ag's
1391 * subtrees for sufficient free space, starting with the leftmost
1392 * subtree.
1393 */
1394 for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1395 /* is there sufficient free space ?
1396 */
1397 if (l2nb > dcp->stree[ti])
1398 continue;
1399
1400 /* sufficient free space found in a subtree. now search down
1401 * the subtree to find the leftmost leaf that describes this
1402 * free space.
1403 */
1404 for (k = bmp->db_agheight; k > 0; k--) {
1405 for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1406 if (l2nb <= dcp->stree[m + n]) {
1407 ti = m + n;
1408 break;
1409 }
1410 }
1411 if (n == 4) {
1412 jfs_error(bmp->db_ipbmap->i_sb,
1413 "failed descending stree\n");
1414 release_metapage(mp);
1415 return -EIO;
1416 }
1417 }
1418
1419 /* determine the block number within the file system
1420 * that corresponds to this leaf.
1421 */
1422 if (bmp->db_aglevel == 2)
1423 blkno = 0;
1424 else if (bmp->db_aglevel == 1)
1425 blkno &= ~(MAXL1SIZE - 1);
1426 else /* bmp->db_aglevel == 0 */
1427 blkno &= ~(MAXL0SIZE - 1);
1428
1429 blkno +=
1430 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1431
1432 /* release the buffer in preparation for going down
1433 * the next level of dmap control pages.
1434 */
1435 release_metapage(mp);
1436
1437 /* check if we need to continue to search down the lower
1438 * level dmap control pages. we need to if the number of
1439 * blocks required is less than maximum number of blocks
1440 * described at the next lower level.
1441 */
1442 if (l2nb < budmin) {
1443
1444 /* search the lower level dmap control pages to get
1445 * the starting block number of the dmap that
1446 * contains or starts off the free space.
1447 */
1448 if ((rc =
1449 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1450 &blkno))) {
1451 if (rc == -ENOSPC) {
1452 jfs_error(bmp->db_ipbmap->i_sb,
1453 "control page inconsistent\n");
1454 return -EIO;
1455 }
1456 return (rc);
1457 }
1458 }
1459
1460 /* allocate the blocks.
1461 */
1462 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1463 if (rc == -ENOSPC) {
1464 jfs_error(bmp->db_ipbmap->i_sb,
1465 "unable to allocate blocks\n");
1466 rc = -EIO;
1467 }
1468 return (rc);
1469 }
1470
1471 /* no space in the allocation group. release the buffer and
1472 * return -ENOSPC.
1473 */
1474 release_metapage(mp);
1475
1476 return -ENOSPC;
1477 }
1478
1479
1480 /*
1481 * NAME: dbAllocAny()
1482 *
1483 * FUNCTION: attempt to allocate the specified number of contiguous
1484 * free blocks anywhere in the file system.
1485 *
1486 * dbAllocAny() attempts to find the sufficient free space by
1487 * searching down the dmap control pages, starting with the
1488 * highest level (i.e. L0, L1, L2) control page. if free space
1489 * large enough to satisfy the desired free space is found, the
1490 * desired free space is allocated.
1491 *
1492 * PARAMETERS:
1493 * bmp - pointer to bmap descriptor
1494 * nblocks - actual number of contiguous free blocks desired.
1495 * l2nb - log2 number of contiguous free blocks desired.
1496 * results - on successful return, set to the starting block number
1497 * of the newly allocated range.
1498 *
1499 * RETURN VALUES:
1500 * 0 - success
1501 * -ENOSPC - insufficient disk resources
1502 * -EIO - i/o error
1503 *
1504 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1505 */
dbAllocAny(struct bmap * bmp,s64 nblocks,int l2nb,s64 * results)1506 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1507 {
1508 int rc;
1509 s64 blkno = 0;
1510
1511 /* starting with the top level dmap control page, search
1512 * down the dmap control levels for sufficient free space.
1513 * if free space is found, dbFindCtl() returns the starting
1514 * block number of the dmap that contains or starts off the
1515 * range of free space.
1516 */
1517 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1518 return (rc);
1519
1520 /* allocate the blocks.
1521 */
1522 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1523 if (rc == -ENOSPC) {
1524 jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n");
1525 return -EIO;
1526 }
1527 return (rc);
1528 }
1529
1530
1531 /*
1532 * NAME: dbDiscardAG()
1533 *
1534 * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG
1535 *
1536 * algorithm:
1537 * 1) allocate blocks, as large as possible and save them
1538 * while holding IWRITE_LOCK on ipbmap
1539 * 2) trim all these saved block/length values
1540 * 3) mark the blocks free again
1541 *
1542 * benefit:
1543 * - we work only on one ag at some time, minimizing how long we
1544 * need to lock ipbmap
1545 * - reading / writing the fs is possible most time, even on
1546 * trimming
1547 *
1548 * downside:
1549 * - we write two times to the dmapctl and dmap pages
1550 * - but for me, this seems the best way, better ideas?
1551 * /TR 2012
1552 *
1553 * PARAMETERS:
1554 * ip - pointer to in-core inode
1555 * agno - ag to trim
1556 * minlen - minimum value of contiguous blocks
1557 *
1558 * RETURN VALUES:
1559 * s64 - actual number of blocks trimmed
1560 */
dbDiscardAG(struct inode * ip,int agno,s64 minlen)1561 s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
1562 {
1563 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
1564 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
1565 s64 nblocks, blkno;
1566 u64 trimmed = 0;
1567 int rc, l2nb;
1568 struct super_block *sb = ipbmap->i_sb;
1569
1570 struct range2trim {
1571 u64 blkno;
1572 u64 nblocks;
1573 } *totrim, *tt;
1574
1575 /* max blkno / nblocks pairs to trim */
1576 int count = 0, range_cnt;
1577 u64 max_ranges;
1578
1579 /* prevent others from writing new stuff here, while trimming */
1580 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
1581
1582 nblocks = bmp->db_agfree[agno];
1583 max_ranges = nblocks;
1584 do_div(max_ranges, minlen);
1585 range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
1586 totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS);
1587 if (totrim == NULL) {
1588 jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n");
1589 IWRITE_UNLOCK(ipbmap);
1590 return 0;
1591 }
1592
1593 tt = totrim;
1594 while (nblocks >= minlen) {
1595 l2nb = BLKSTOL2(nblocks);
1596
1597 /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
1598 rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
1599 if (rc == 0) {
1600 tt->blkno = blkno;
1601 tt->nblocks = nblocks;
1602 tt++; count++;
1603
1604 /* the whole ag is free, trim now */
1605 if (bmp->db_agfree[agno] == 0)
1606 break;
1607
1608 /* give a hint for the next while */
1609 nblocks = bmp->db_agfree[agno];
1610 continue;
1611 } else if (rc == -ENOSPC) {
1612 /* search for next smaller log2 block */
1613 l2nb = BLKSTOL2(nblocks) - 1;
1614 if (unlikely(l2nb < 0))
1615 break;
1616 nblocks = 1LL << l2nb;
1617 } else {
1618 /* Trim any already allocated blocks */
1619 jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
1620 break;
1621 }
1622
1623 /* check, if our trim array is full */
1624 if (unlikely(count >= range_cnt - 1))
1625 break;
1626 }
1627 IWRITE_UNLOCK(ipbmap);
1628
1629 tt->nblocks = 0; /* mark the current end */
1630 for (tt = totrim; tt->nblocks != 0; tt++) {
1631 /* when mounted with online discard, dbFree() will
1632 * call jfs_issue_discard() itself */
1633 if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
1634 jfs_issue_discard(ip, tt->blkno, tt->nblocks);
1635 dbFree(ip, tt->blkno, tt->nblocks);
1636 trimmed += tt->nblocks;
1637 }
1638 kfree(totrim);
1639
1640 return trimmed;
1641 }
1642
1643 /*
1644 * NAME: dbFindCtl()
1645 *
1646 * FUNCTION: starting at a specified dmap control page level and block
1647 * number, search down the dmap control levels for a range of
1648 * contiguous free blocks large enough to satisfy an allocation
1649 * request for the specified number of free blocks.
1650 *
1651 * if sufficient contiguous free blocks are found, this routine
1652 * returns the starting block number within a dmap page that
1653 * contains or starts a range of contiqious free blocks that
1654 * is sufficient in size.
1655 *
1656 * PARAMETERS:
1657 * bmp - pointer to bmap descriptor
1658 * level - starting dmap control page level.
1659 * l2nb - log2 number of contiguous free blocks desired.
1660 * *blkno - on entry, starting block number for conducting the search.
1661 * on successful return, the first block within a dmap page
1662 * that contains or starts a range of contiguous free blocks.
1663 *
1664 * RETURN VALUES:
1665 * 0 - success
1666 * -ENOSPC - insufficient disk resources
1667 * -EIO - i/o error
1668 *
1669 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1670 */
dbFindCtl(struct bmap * bmp,int l2nb,int level,s64 * blkno)1671 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1672 {
1673 int rc, leafidx, lev;
1674 s64 b, lblkno;
1675 struct dmapctl *dcp;
1676 int budmin;
1677 struct metapage *mp;
1678
1679 /* starting at the specified dmap control page level and block
1680 * number, search down the dmap control levels for the starting
1681 * block number of a dmap page that contains or starts off
1682 * sufficient free blocks.
1683 */
1684 for (lev = level, b = *blkno; lev >= 0; lev--) {
1685 /* get the buffer of the dmap control page for the block
1686 * number and level (i.e. L0, L1, L2).
1687 */
1688 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1689 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1690 if (mp == NULL)
1691 return -EIO;
1692 dcp = (struct dmapctl *) mp->data;
1693 budmin = dcp->budmin;
1694
1695 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1696 jfs_error(bmp->db_ipbmap->i_sb,
1697 "Corrupt dmapctl page\n");
1698 release_metapage(mp);
1699 return -EIO;
1700 }
1701
1702 /* search the tree within the dmap control page for
1703 * sufficient free space. if sufficient free space is found,
1704 * dbFindLeaf() returns the index of the leaf at which
1705 * free space was found.
1706 */
1707 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx, true);
1708
1709 /* release the buffer.
1710 */
1711 release_metapage(mp);
1712
1713 /* space found ?
1714 */
1715 if (rc) {
1716 if (lev != level) {
1717 jfs_error(bmp->db_ipbmap->i_sb,
1718 "dmap inconsistent\n");
1719 return -EIO;
1720 }
1721 return -ENOSPC;
1722 }
1723
1724 /* adjust the block number to reflect the location within
1725 * the dmap control page (i.e. the leaf) at which free
1726 * space was found.
1727 */
1728 b += (((s64) leafidx) << budmin);
1729
1730 /* we stop the search at this dmap control page level if
1731 * the number of blocks required is greater than or equal
1732 * to the maximum number of blocks described at the next
1733 * (lower) level.
1734 */
1735 if (l2nb >= budmin)
1736 break;
1737 }
1738
1739 *blkno = b;
1740 return (0);
1741 }
1742
1743
1744 /*
1745 * NAME: dbAllocCtl()
1746 *
1747 * FUNCTION: attempt to allocate a specified number of contiguous
1748 * blocks starting within a specific dmap.
1749 *
1750 * this routine is called by higher level routines that search
1751 * the dmap control pages above the actual dmaps for contiguous
1752 * free space. the result of successful searches by these
1753 * routines are the starting block numbers within dmaps, with
1754 * the dmaps themselves containing the desired contiguous free
1755 * space or starting a contiguous free space of desired size
1756 * that is made up of the blocks of one or more dmaps. these
1757 * calls should not fail due to insufficent resources.
1758 *
1759 * this routine is called in some cases where it is not known
1760 * whether it will fail due to insufficient resources. more
1761 * specifically, this occurs when allocating from an allocation
1762 * group whose size is equal to the number of blocks per dmap.
1763 * in this case, the dmap control pages are not examined prior
1764 * to calling this routine (to save pathlength) and the call
1765 * might fail.
1766 *
1767 * for a request size that fits within a dmap, this routine relies
1768 * upon the dmap's dmtree to find the requested contiguous free
1769 * space. for request sizes that are larger than a dmap, the
1770 * requested free space will start at the first block of the
1771 * first dmap (i.e. blkno).
1772 *
1773 * PARAMETERS:
1774 * bmp - pointer to bmap descriptor
1775 * nblocks - actual number of contiguous free blocks to allocate.
1776 * l2nb - log2 number of contiguous free blocks to allocate.
1777 * blkno - starting block number of the dmap to start the allocation
1778 * from.
1779 * results - on successful return, set to the starting block number
1780 * of the newly allocated range.
1781 *
1782 * RETURN VALUES:
1783 * 0 - success
1784 * -ENOSPC - insufficient disk resources
1785 * -EIO - i/o error
1786 *
1787 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1788 */
1789 static int
dbAllocCtl(struct bmap * bmp,s64 nblocks,int l2nb,s64 blkno,s64 * results)1790 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1791 {
1792 int rc, nb;
1793 s64 b, lblkno, n;
1794 struct metapage *mp;
1795 struct dmap *dp;
1796
1797 /* check if the allocation request is confined to a single dmap.
1798 */
1799 if (l2nb <= L2BPERDMAP) {
1800 /* get the buffer for the dmap.
1801 */
1802 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1803 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1804 if (mp == NULL)
1805 return -EIO;
1806 dp = (struct dmap *) mp->data;
1807
1808 if (dp->tree.budmin < 0)
1809 return -EIO;
1810
1811 /* try to allocate the blocks.
1812 */
1813 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1814 if (rc == 0)
1815 mark_metapage_dirty(mp);
1816
1817 release_metapage(mp);
1818
1819 return (rc);
1820 }
1821
1822 /* allocation request involving multiple dmaps. it must start on
1823 * a dmap boundary.
1824 */
1825 assert((blkno & (BPERDMAP - 1)) == 0);
1826
1827 /* allocate the blocks dmap by dmap.
1828 */
1829 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1830 /* get the buffer for the dmap.
1831 */
1832 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1833 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1834 if (mp == NULL) {
1835 rc = -EIO;
1836 goto backout;
1837 }
1838 dp = (struct dmap *) mp->data;
1839
1840 /* the dmap better be all free.
1841 */
1842 if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1843 release_metapage(mp);
1844 jfs_error(bmp->db_ipbmap->i_sb,
1845 "the dmap is not all free\n");
1846 rc = -EIO;
1847 goto backout;
1848 }
1849
1850 /* determine how many blocks to allocate from this dmap.
1851 */
1852 nb = min_t(s64, n, BPERDMAP);
1853
1854 /* allocate the blocks from the dmap.
1855 */
1856 if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1857 release_metapage(mp);
1858 goto backout;
1859 }
1860
1861 /* write the buffer.
1862 */
1863 write_metapage(mp);
1864 }
1865
1866 /* set the results (starting block number) and return.
1867 */
1868 *results = blkno;
1869 return (0);
1870
1871 /* something failed in handling an allocation request involving
1872 * multiple dmaps. we'll try to clean up by backing out any
1873 * allocation that has already happened for this request. if
1874 * we fail in backing out the allocation, we'll mark the file
1875 * system to indicate that blocks have been leaked.
1876 */
1877 backout:
1878
1879 /* try to backout the allocations dmap by dmap.
1880 */
1881 for (n = nblocks - n, b = blkno; n > 0;
1882 n -= BPERDMAP, b += BPERDMAP) {
1883 /* get the buffer for this dmap.
1884 */
1885 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1886 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1887 if (mp == NULL) {
1888 /* could not back out. mark the file system
1889 * to indicate that we have leaked blocks.
1890 */
1891 jfs_error(bmp->db_ipbmap->i_sb,
1892 "I/O Error: Block Leakage\n");
1893 continue;
1894 }
1895 dp = (struct dmap *) mp->data;
1896
1897 /* free the blocks is this dmap.
1898 */
1899 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1900 /* could not back out. mark the file system
1901 * to indicate that we have leaked blocks.
1902 */
1903 release_metapage(mp);
1904 jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n");
1905 continue;
1906 }
1907
1908 /* write the buffer.
1909 */
1910 write_metapage(mp);
1911 }
1912
1913 return (rc);
1914 }
1915
1916
1917 /*
1918 * NAME: dbAllocDmapLev()
1919 *
1920 * FUNCTION: attempt to allocate a specified number of contiguous blocks
1921 * from a specified dmap.
1922 *
1923 * this routine checks if the contiguous blocks are available.
1924 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1925 * returned.
1926 *
1927 * PARAMETERS:
1928 * mp - pointer to bmap descriptor
1929 * dp - pointer to dmap to attempt to allocate blocks from.
1930 * l2nb - log2 number of contiguous block desired.
1931 * nblocks - actual number of contiguous block desired.
1932 * results - on successful return, set to the starting block number
1933 * of the newly allocated range.
1934 *
1935 * RETURN VALUES:
1936 * 0 - success
1937 * -ENOSPC - insufficient disk resources
1938 * -EIO - i/o error
1939 *
1940 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1941 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1942 */
1943 static int
dbAllocDmapLev(struct bmap * bmp,struct dmap * dp,int nblocks,int l2nb,s64 * results)1944 dbAllocDmapLev(struct bmap * bmp,
1945 struct dmap * dp, int nblocks, int l2nb, s64 * results)
1946 {
1947 s64 blkno;
1948 int leafidx, rc;
1949
1950 /* can't be more than a dmaps worth of blocks */
1951 assert(l2nb <= L2BPERDMAP);
1952
1953 /* search the tree within the dmap page for sufficient
1954 * free space. if sufficient free space is found, dbFindLeaf()
1955 * returns the index of the leaf at which free space was found.
1956 */
1957 if (dbFindLeaf((dmtree_t *) &dp->tree, l2nb, &leafidx, false))
1958 return -ENOSPC;
1959
1960 if (leafidx < 0)
1961 return -EIO;
1962
1963 /* determine the block number within the file system corresponding
1964 * to the leaf at which free space was found.
1965 */
1966 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1967
1968 /* if not all bits of the dmap word are free, get the starting
1969 * bit number within the dmap word of the required string of free
1970 * bits and adjust the block number with this value.
1971 */
1972 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1973 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1974
1975 /* allocate the blocks */
1976 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1977 *results = blkno;
1978
1979 return (rc);
1980 }
1981
1982
1983 /*
1984 * NAME: dbAllocDmap()
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 allocates the specified blocks from the dmap
1990 * through a call to dbAllocBits(). if the allocation of the
1991 * block range causes the maximum string of free blocks within
1992 * the dmap to change (i.e. the value of the root of the dmap's
1993 * dmtree), this routine will cause this change to be reflected
1994 * up through the appropriate levels of the dmap control pages
1995 * by a call to dbAdjCtl() for the L0 dmap control page that
1996 * covers this dmap.
1997 *
1998 * PARAMETERS:
1999 * bmp - pointer to bmap descriptor
2000 * dp - pointer to dmap to allocate the block range from.
2001 * blkno - starting block number of the block to be allocated.
2002 * nblocks - number of blocks to be allocated.
2003 *
2004 * RETURN VALUES:
2005 * 0 - success
2006 * -EIO - i/o error
2007 *
2008 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2009 */
dbAllocDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2010 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2011 int nblocks)
2012 {
2013 s8 oldroot;
2014 int rc;
2015
2016 /* save the current value of the root (i.e. maximum free string)
2017 * of the dmap tree.
2018 */
2019 oldroot = dp->tree.stree[ROOT];
2020
2021 /* allocate the specified (blocks) bits */
2022 dbAllocBits(bmp, dp, blkno, nblocks);
2023
2024 /* if the root has not changed, done. */
2025 if (dp->tree.stree[ROOT] == oldroot)
2026 return (0);
2027
2028 /* root changed. bubble the change up to the dmap control pages.
2029 * if the adjustment of the upper level control pages fails,
2030 * backout the bit allocation (thus making everything consistent).
2031 */
2032 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
2033 dbFreeBits(bmp, dp, blkno, nblocks);
2034
2035 return (rc);
2036 }
2037
2038
2039 /*
2040 * NAME: dbFreeDmap()
2041 *
2042 * FUNCTION: adjust the disk allocation map to reflect the allocation
2043 * of a specified block range within a dmap.
2044 *
2045 * this routine frees the specified blocks from the dmap through
2046 * a call to dbFreeBits(). if the deallocation of the block range
2047 * causes the maximum string of free blocks within the dmap to
2048 * change (i.e. the value of the root of the dmap's dmtree), this
2049 * routine will cause this change to be reflected up through the
2050 * appropriate levels of the dmap control pages by a call to
2051 * dbAdjCtl() for the L0 dmap control page that covers this dmap.
2052 *
2053 * PARAMETERS:
2054 * bmp - pointer to bmap descriptor
2055 * dp - pointer to dmap to free the block range from.
2056 * blkno - starting block number of the block to be freed.
2057 * nblocks - number of blocks to be freed.
2058 *
2059 * RETURN VALUES:
2060 * 0 - success
2061 * -EIO - i/o error
2062 *
2063 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2064 */
dbFreeDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2065 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2066 int nblocks)
2067 {
2068 s8 oldroot;
2069 int rc = 0, word;
2070
2071 /* save the current value of the root (i.e. maximum free string)
2072 * of the dmap tree.
2073 */
2074 oldroot = dp->tree.stree[ROOT];
2075
2076 /* free the specified (blocks) bits */
2077 rc = dbFreeBits(bmp, dp, blkno, nblocks);
2078
2079 /* if error or the root has not changed, done. */
2080 if (rc || (dp->tree.stree[ROOT] == oldroot))
2081 return (rc);
2082
2083 /* root changed. bubble the change up to the dmap control pages.
2084 * if the adjustment of the upper level control pages fails,
2085 * backout the deallocation.
2086 */
2087 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2088 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2089
2090 /* as part of backing out the deallocation, we will have
2091 * to back split the dmap tree if the deallocation caused
2092 * the freed blocks to become part of a larger binary buddy
2093 * system.
2094 */
2095 if (dp->tree.stree[word] == NOFREE)
2096 dbBackSplit((dmtree_t *)&dp->tree, word, false);
2097
2098 dbAllocBits(bmp, dp, blkno, nblocks);
2099 }
2100
2101 return (rc);
2102 }
2103
2104
2105 /*
2106 * NAME: dbAllocBits()
2107 *
2108 * FUNCTION: allocate a specified block range from a dmap.
2109 *
2110 * this routine updates the dmap to reflect the working
2111 * state allocation of the specified block range. it directly
2112 * updates the bits of the working map and causes the adjustment
2113 * of the binary buddy system described by the dmap's dmtree
2114 * leaves to reflect the bits allocated. it also causes the
2115 * dmap's dmtree, as a whole, to reflect the allocated range.
2116 *
2117 * PARAMETERS:
2118 * bmp - pointer to bmap descriptor
2119 * dp - pointer to dmap to allocate bits from.
2120 * blkno - starting block number of the bits to be allocated.
2121 * nblocks - number of bits to be allocated.
2122 *
2123 * RETURN VALUES: none
2124 *
2125 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2126 */
dbAllocBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2127 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2128 int nblocks)
2129 {
2130 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2131 dmtree_t *tp = (dmtree_t *) & dp->tree;
2132 int size;
2133 s8 *leaf;
2134
2135 /* pick up a pointer to the leaves of the dmap tree */
2136 leaf = dp->tree.stree + LEAFIND;
2137
2138 /* determine the bit number and word within the dmap of the
2139 * starting block.
2140 */
2141 dbitno = blkno & (BPERDMAP - 1);
2142 word = dbitno >> L2DBWORD;
2143
2144 /* block range better be within the dmap */
2145 assert(dbitno + nblocks <= BPERDMAP);
2146
2147 /* allocate the bits of the dmap's words corresponding to the block
2148 * range. not all bits of the first and last words may be contained
2149 * within the block range. if this is the case, we'll work against
2150 * those words (i.e. partial first and/or last) on an individual basis
2151 * (a single pass), allocating the bits of interest by hand and
2152 * updating the leaf corresponding to the dmap word. a single pass
2153 * will be used for all dmap words fully contained within the
2154 * specified range. within this pass, the bits of all fully contained
2155 * dmap words will be marked as free in a single shot and the leaves
2156 * will be updated. a single leaf may describe the free space of
2157 * multiple dmap words, so we may update only a subset of the actual
2158 * leaves corresponding to the dmap words of the block range.
2159 */
2160 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2161 /* determine the bit number within the word and
2162 * the number of bits within the word.
2163 */
2164 wbitno = dbitno & (DBWORD - 1);
2165 nb = min(rembits, DBWORD - wbitno);
2166
2167 /* check if only part of a word is to be allocated.
2168 */
2169 if (nb < DBWORD) {
2170 /* allocate (set to 1) the appropriate bits within
2171 * this dmap word.
2172 */
2173 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2174 >> wbitno);
2175
2176 /* update the leaf for this dmap word. in addition
2177 * to setting the leaf value to the binary buddy max
2178 * of the updated dmap word, dbSplit() will split
2179 * the binary system of the leaves if need be.
2180 */
2181 dbSplit(tp, word, BUDMIN,
2182 dbMaxBud((u8 *)&dp->wmap[word]), false);
2183
2184 word += 1;
2185 } else {
2186 /* one or more dmap words are fully contained
2187 * within the block range. determine how many
2188 * words and allocate (set to 1) the bits of these
2189 * words.
2190 */
2191 nwords = rembits >> L2DBWORD;
2192 memset(&dp->wmap[word], (int) ONES, nwords * 4);
2193
2194 /* determine how many bits.
2195 */
2196 nb = nwords << L2DBWORD;
2197
2198 /* now update the appropriate leaves to reflect
2199 * the allocated words.
2200 */
2201 for (; nwords > 0; nwords -= nw) {
2202 if (leaf[word] < BUDMIN) {
2203 jfs_error(bmp->db_ipbmap->i_sb,
2204 "leaf page corrupt\n");
2205 break;
2206 }
2207
2208 /* determine what the leaf value should be
2209 * updated to as the minimum of the l2 number
2210 * of bits being allocated and the l2 number
2211 * of bits currently described by this leaf.
2212 */
2213 size = min_t(int, leaf[word],
2214 NLSTOL2BSZ(nwords));
2215
2216 /* update the leaf to reflect the allocation.
2217 * in addition to setting the leaf value to
2218 * NOFREE, dbSplit() will split the binary
2219 * system of the leaves to reflect the current
2220 * allocation (size).
2221 */
2222 dbSplit(tp, word, size, NOFREE, false);
2223
2224 /* get the number of dmap words handled */
2225 nw = BUDSIZE(size, BUDMIN);
2226 word += nw;
2227 }
2228 }
2229 }
2230
2231 /* update the free count for this dmap */
2232 le32_add_cpu(&dp->nfree, -nblocks);
2233
2234 BMAP_LOCK(bmp);
2235
2236 /* if this allocation group is completely free,
2237 * update the maximum allocation group number if this allocation
2238 * group is the new max.
2239 */
2240 agno = blkno >> bmp->db_agl2size;
2241 if (agno > bmp->db_maxag)
2242 bmp->db_maxag = agno;
2243
2244 /* update the free count for the allocation group and map */
2245 bmp->db_agfree[agno] -= nblocks;
2246 bmp->db_nfree -= nblocks;
2247
2248 BMAP_UNLOCK(bmp);
2249 }
2250
2251
2252 /*
2253 * NAME: dbFreeBits()
2254 *
2255 * FUNCTION: free a specified block range from a dmap.
2256 *
2257 * this routine updates the dmap to reflect the working
2258 * state allocation of the specified block range. it directly
2259 * updates the bits of the working map and causes the adjustment
2260 * of the binary buddy system described by the dmap's dmtree
2261 * leaves to reflect the bits freed. it also causes the dmap's
2262 * dmtree, as a whole, to reflect the deallocated range.
2263 *
2264 * PARAMETERS:
2265 * bmp - pointer to bmap descriptor
2266 * dp - pointer to dmap to free bits from.
2267 * blkno - starting block number of the bits to be freed.
2268 * nblocks - number of bits to be freed.
2269 *
2270 * RETURN VALUES: 0 for success
2271 *
2272 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2273 */
dbFreeBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2274 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2275 int nblocks)
2276 {
2277 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2278 dmtree_t *tp = (dmtree_t *) & dp->tree;
2279 int rc = 0;
2280 int size;
2281
2282 /* determine the bit number and word within the dmap of the
2283 * starting block.
2284 */
2285 dbitno = blkno & (BPERDMAP - 1);
2286 word = dbitno >> L2DBWORD;
2287
2288 /* block range better be within the dmap.
2289 */
2290 assert(dbitno + nblocks <= BPERDMAP);
2291
2292 /* free the bits of the dmaps words corresponding to the block range.
2293 * not all bits of the first and last words may be contained within
2294 * the block range. if this is the case, we'll work against those
2295 * words (i.e. partial first and/or last) on an individual basis
2296 * (a single pass), freeing the bits of interest by hand and updating
2297 * the leaf corresponding to the dmap word. a single pass will be used
2298 * for all dmap words fully contained within the specified range.
2299 * within this pass, the bits of all fully contained dmap words will
2300 * be marked as free in a single shot and the leaves will be updated. a
2301 * single leaf may describe the free space of multiple dmap words,
2302 * so we may update only a subset of the actual leaves corresponding
2303 * to the dmap words of the block range.
2304 *
2305 * dbJoin() is used to update leaf values and will join the binary
2306 * buddy system of the leaves if the new leaf values indicate this
2307 * should be done.
2308 */
2309 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2310 /* determine the bit number within the word and
2311 * the number of bits within the word.
2312 */
2313 wbitno = dbitno & (DBWORD - 1);
2314 nb = min(rembits, DBWORD - wbitno);
2315
2316 /* check if only part of a word is to be freed.
2317 */
2318 if (nb < DBWORD) {
2319 /* free (zero) the appropriate bits within this
2320 * dmap word.
2321 */
2322 dp->wmap[word] &=
2323 cpu_to_le32(~(ONES << (DBWORD - nb)
2324 >> wbitno));
2325
2326 /* update the leaf for this dmap word.
2327 */
2328 rc = dbJoin(tp, word,
2329 dbMaxBud((u8 *)&dp->wmap[word]), false);
2330 if (rc)
2331 return rc;
2332
2333 word += 1;
2334 } else {
2335 /* one or more dmap words are fully contained
2336 * within the block range. determine how many
2337 * words and free (zero) the bits of these words.
2338 */
2339 nwords = rembits >> L2DBWORD;
2340 memset(&dp->wmap[word], 0, nwords * 4);
2341
2342 /* determine how many bits.
2343 */
2344 nb = nwords << L2DBWORD;
2345
2346 /* now update the appropriate leaves to reflect
2347 * the freed words.
2348 */
2349 for (; nwords > 0; nwords -= nw) {
2350 /* determine what the leaf value should be
2351 * updated to as the minimum of the l2 number
2352 * of bits being freed and the l2 (max) number
2353 * of bits that can be described by this leaf.
2354 */
2355 size =
2356 min(LITOL2BSZ
2357 (word, L2LPERDMAP, BUDMIN),
2358 NLSTOL2BSZ(nwords));
2359
2360 /* update the leaf.
2361 */
2362 rc = dbJoin(tp, word, size, false);
2363 if (rc)
2364 return rc;
2365
2366 /* get the number of dmap words handled.
2367 */
2368 nw = BUDSIZE(size, BUDMIN);
2369 word += nw;
2370 }
2371 }
2372 }
2373
2374 /* update the free count for this dmap.
2375 */
2376 le32_add_cpu(&dp->nfree, nblocks);
2377
2378 BMAP_LOCK(bmp);
2379
2380 /* update the free count for the allocation group and
2381 * map.
2382 */
2383 agno = blkno >> bmp->db_agl2size;
2384 bmp->db_nfree += nblocks;
2385 bmp->db_agfree[agno] += nblocks;
2386
2387 /* check if this allocation group is not completely free and
2388 * if it is currently the maximum (rightmost) allocation group.
2389 * if so, establish the new maximum allocation group number by
2390 * searching left for the first allocation group with allocation.
2391 */
2392 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2393 (agno == bmp->db_numag - 1 &&
2394 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2395 while (bmp->db_maxag > 0) {
2396 bmp->db_maxag -= 1;
2397 if (bmp->db_agfree[bmp->db_maxag] !=
2398 bmp->db_agsize)
2399 break;
2400 }
2401
2402 /* re-establish the allocation group preference if the
2403 * current preference is right of the maximum allocation
2404 * group.
2405 */
2406 if (bmp->db_agpref > bmp->db_maxag)
2407 bmp->db_agpref = bmp->db_maxag;
2408 }
2409
2410 BMAP_UNLOCK(bmp);
2411
2412 return 0;
2413 }
2414
2415
2416 /*
2417 * NAME: dbAdjCtl()
2418 *
2419 * FUNCTION: adjust a dmap control page at a specified level to reflect
2420 * the change in a lower level dmap or dmap control page's
2421 * maximum string of free blocks (i.e. a change in the root
2422 * of the lower level object's dmtree) due to the allocation
2423 * or deallocation of a range of blocks with a single dmap.
2424 *
2425 * on entry, this routine is provided with the new value of
2426 * the lower level dmap or dmap control page root and the
2427 * starting block number of the block range whose allocation
2428 * or deallocation resulted in the root change. this range
2429 * is respresented by a single leaf of the current dmapctl
2430 * and the leaf will be updated with this value, possibly
2431 * causing a binary buddy system within the leaves to be
2432 * split or joined. the update may also cause the dmapctl's
2433 * dmtree to be updated.
2434 *
2435 * if the adjustment of the dmap control page, itself, causes its
2436 * root to change, this change will be bubbled up to the next dmap
2437 * control level by a recursive call to this routine, specifying
2438 * the new root value and the next dmap control page level to
2439 * be adjusted.
2440 * PARAMETERS:
2441 * bmp - pointer to bmap descriptor
2442 * blkno - the first block of a block range within a dmap. it is
2443 * the allocation or deallocation of this block range that
2444 * requires the dmap control page to be adjusted.
2445 * newval - the new value of the lower level dmap or dmap control
2446 * page root.
2447 * alloc - 'true' if adjustment is due to an allocation.
2448 * level - current level of dmap control page (i.e. L0, L1, L2) to
2449 * be adjusted.
2450 *
2451 * RETURN VALUES:
2452 * 0 - success
2453 * -EIO - i/o error
2454 *
2455 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2456 */
2457 static int
dbAdjCtl(struct bmap * bmp,s64 blkno,int newval,int alloc,int level)2458 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2459 {
2460 struct metapage *mp;
2461 s8 oldroot;
2462 int oldval;
2463 s64 lblkno;
2464 struct dmapctl *dcp;
2465 int rc, leafno, ti;
2466
2467 /* get the buffer for the dmap control page for the specified
2468 * block number and control page level.
2469 */
2470 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2471 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2472 if (mp == NULL)
2473 return -EIO;
2474 dcp = (struct dmapctl *) mp->data;
2475
2476 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2477 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
2478 release_metapage(mp);
2479 return -EIO;
2480 }
2481
2482 /* determine the leaf number corresponding to the block and
2483 * the index within the dmap control tree.
2484 */
2485 leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2486 ti = leafno + le32_to_cpu(dcp->leafidx);
2487
2488 /* save the current leaf value and the current root level (i.e.
2489 * maximum l2 free string described by this dmapctl).
2490 */
2491 oldval = dcp->stree[ti];
2492 oldroot = dcp->stree[ROOT];
2493
2494 /* check if this is a control page update for an allocation.
2495 * if so, update the leaf to reflect the new leaf value using
2496 * dbSplit(); otherwise (deallocation), use dbJoin() to update
2497 * the leaf with the new value. in addition to updating the
2498 * leaf, dbSplit() will also split the binary buddy system of
2499 * the leaves, if required, and bubble new values within the
2500 * dmapctl tree, if required. similarly, dbJoin() will join
2501 * the binary buddy system of leaves and bubble new values up
2502 * the dmapctl tree as required by the new leaf value.
2503 */
2504 if (alloc) {
2505 /* check if we are in the middle of a binary buddy
2506 * system. this happens when we are performing the
2507 * first allocation out of an allocation group that
2508 * is part (not the first part) of a larger binary
2509 * buddy system. if we are in the middle, back split
2510 * the system prior to calling dbSplit() which assumes
2511 * that it is at the front of a binary buddy system.
2512 */
2513 if (oldval == NOFREE) {
2514 rc = dbBackSplit((dmtree_t *)dcp, leafno, true);
2515 if (rc) {
2516 release_metapage(mp);
2517 return rc;
2518 }
2519 oldval = dcp->stree[ti];
2520 }
2521 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval, true);
2522 } else {
2523 rc = dbJoin((dmtree_t *) dcp, leafno, newval, true);
2524 if (rc) {
2525 release_metapage(mp);
2526 return rc;
2527 }
2528 }
2529
2530 /* check if the root of the current dmap control page changed due
2531 * to the update and if the current dmap control page is not at
2532 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
2533 * root changed and this is not the top level), call this routine
2534 * again (recursion) for the next higher level of the mapping to
2535 * reflect the change in root for the current dmap control page.
2536 */
2537 if (dcp->stree[ROOT] != oldroot) {
2538 /* are we below the top level of the map. if so,
2539 * bubble the root up to the next higher level.
2540 */
2541 if (level < bmp->db_maxlevel) {
2542 /* bubble up the new root of this dmap control page to
2543 * the next level.
2544 */
2545 if ((rc =
2546 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2547 level + 1))) {
2548 /* something went wrong in bubbling up the new
2549 * root value, so backout the changes to the
2550 * current dmap control page.
2551 */
2552 if (alloc) {
2553 dbJoin((dmtree_t *) dcp, leafno,
2554 oldval, true);
2555 } else {
2556 /* the dbJoin() above might have
2557 * caused a larger binary buddy system
2558 * to form and we may now be in the
2559 * middle of it. if this is the case,
2560 * back split the buddies.
2561 */
2562 if (dcp->stree[ti] == NOFREE)
2563 dbBackSplit((dmtree_t *)
2564 dcp, leafno, true);
2565 dbSplit((dmtree_t *) dcp, leafno,
2566 dcp->budmin, oldval, true);
2567 }
2568
2569 /* release the buffer and return the error.
2570 */
2571 release_metapage(mp);
2572 return (rc);
2573 }
2574 } else {
2575 /* we're at the top level of the map. update
2576 * the bmap control page to reflect the size
2577 * of the maximum free buddy system.
2578 */
2579 assert(level == bmp->db_maxlevel);
2580 if (bmp->db_maxfreebud != oldroot) {
2581 jfs_error(bmp->db_ipbmap->i_sb,
2582 "the maximum free buddy is not the old root\n");
2583 }
2584 bmp->db_maxfreebud = dcp->stree[ROOT];
2585 }
2586 }
2587
2588 /* write the buffer.
2589 */
2590 write_metapage(mp);
2591
2592 return (0);
2593 }
2594
2595
2596 /*
2597 * NAME: dbSplit()
2598 *
2599 * FUNCTION: update the leaf of a dmtree with a new value, splitting
2600 * the leaf from the binary buddy system of the dmtree's
2601 * leaves, as required.
2602 *
2603 * PARAMETERS:
2604 * tp - pointer to the tree containing the leaf.
2605 * leafno - the number of the leaf to be updated.
2606 * splitsz - the size the binary buddy system starting at the leaf
2607 * must be split to, specified as the log2 number of blocks.
2608 * newval - the new value for the leaf.
2609 *
2610 * RETURN VALUES: none
2611 *
2612 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2613 */
dbSplit(dmtree_t * tp,int leafno,int splitsz,int newval,bool is_ctl)2614 static void dbSplit(dmtree_t *tp, int leafno, int splitsz, int newval, bool is_ctl)
2615 {
2616 int budsz;
2617 int cursz;
2618 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2619
2620 /* check if the leaf needs to be split.
2621 */
2622 if (leaf[leafno] > tp->dmt_budmin) {
2623 /* the split occurs by cutting the buddy system in half
2624 * at the specified leaf until we reach the specified
2625 * size. pick up the starting split size (current size
2626 * - 1 in l2) and the corresponding buddy size.
2627 */
2628 cursz = leaf[leafno] - 1;
2629 budsz = BUDSIZE(cursz, tp->dmt_budmin);
2630
2631 /* split until we reach the specified size.
2632 */
2633 while (cursz >= splitsz) {
2634 /* update the buddy's leaf with its new value.
2635 */
2636 dbAdjTree(tp, leafno ^ budsz, cursz, is_ctl);
2637
2638 /* on to the next size and buddy.
2639 */
2640 cursz -= 1;
2641 budsz >>= 1;
2642 }
2643 }
2644
2645 /* adjust the dmap tree to reflect the specified leaf's new
2646 * value.
2647 */
2648 dbAdjTree(tp, leafno, newval, is_ctl);
2649 }
2650
2651
2652 /*
2653 * NAME: dbBackSplit()
2654 *
2655 * FUNCTION: back split the binary buddy system of dmtree leaves
2656 * that hold a specified leaf until the specified leaf
2657 * starts its own binary buddy system.
2658 *
2659 * the allocators typically perform allocations at the start
2660 * of binary buddy systems and dbSplit() is used to accomplish
2661 * any required splits. in some cases, however, allocation
2662 * may occur in the middle of a binary system and requires a
2663 * back split, with the split proceeding out from the middle of
2664 * the system (less efficient) rather than the start of the
2665 * system (more efficient). the cases in which a back split
2666 * is required are rare and are limited to the first allocation
2667 * within an allocation group which is a part (not first part)
2668 * of a larger binary buddy system and a few exception cases
2669 * in which a previous join operation must be backed out.
2670 *
2671 * PARAMETERS:
2672 * tp - pointer to the tree containing the leaf.
2673 * leafno - the number of the leaf to be updated.
2674 *
2675 * RETURN VALUES: none
2676 *
2677 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2678 */
dbBackSplit(dmtree_t * tp,int leafno,bool is_ctl)2679 static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl)
2680 {
2681 int budsz, bud, w, bsz, size;
2682 int cursz;
2683 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2684
2685 /* leaf should be part (not first part) of a binary
2686 * buddy system.
2687 */
2688 assert(leaf[leafno] == NOFREE);
2689
2690 /* the back split is accomplished by iteratively finding the leaf
2691 * that starts the buddy system that contains the specified leaf and
2692 * splitting that system in two. this iteration continues until
2693 * the specified leaf becomes the start of a buddy system.
2694 *
2695 * determine maximum possible l2 size for the specified leaf.
2696 */
2697 size =
2698 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2699 tp->dmt_budmin);
2700
2701 /* determine the number of leaves covered by this size. this
2702 * is the buddy size that we will start with as we search for
2703 * the buddy system that contains the specified leaf.
2704 */
2705 budsz = BUDSIZE(size, tp->dmt_budmin);
2706
2707 /* back split.
2708 */
2709 while (leaf[leafno] == NOFREE) {
2710 /* find the leftmost buddy leaf.
2711 */
2712 for (w = leafno, bsz = budsz;; bsz <<= 1,
2713 w = (w < bud) ? w : bud) {
2714 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2715 jfs_err("JFS: block map error in dbBackSplit");
2716 return -EIO;
2717 }
2718
2719 /* determine the buddy.
2720 */
2721 bud = w ^ bsz;
2722
2723 /* check if this buddy is the start of the system.
2724 */
2725 if (leaf[bud] != NOFREE) {
2726 /* split the leaf at the start of the
2727 * system in two.
2728 */
2729 cursz = leaf[bud] - 1;
2730 dbSplit(tp, bud, cursz, cursz, is_ctl);
2731 break;
2732 }
2733 }
2734 }
2735
2736 if (leaf[leafno] != size) {
2737 jfs_err("JFS: wrong leaf value in dbBackSplit");
2738 return -EIO;
2739 }
2740 return 0;
2741 }
2742
2743
2744 /*
2745 * NAME: dbJoin()
2746 *
2747 * FUNCTION: update the leaf of a dmtree with a new value, joining
2748 * the leaf with other leaves of the dmtree into a multi-leaf
2749 * binary buddy system, as required.
2750 *
2751 * PARAMETERS:
2752 * tp - pointer to the tree containing the leaf.
2753 * leafno - the number of the leaf to be updated.
2754 * newval - the new value for the leaf.
2755 *
2756 * RETURN VALUES: none
2757 */
dbJoin(dmtree_t * tp,int leafno,int newval,bool is_ctl)2758 static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl)
2759 {
2760 int budsz, buddy;
2761 s8 *leaf;
2762
2763 /* can the new leaf value require a join with other leaves ?
2764 */
2765 if (newval >= tp->dmt_budmin) {
2766 /* pickup a pointer to the leaves of the tree.
2767 */
2768 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2769
2770 /* try to join the specified leaf into a large binary
2771 * buddy system. the join proceeds by attempting to join
2772 * the specified leafno with its buddy (leaf) at new value.
2773 * if the join occurs, we attempt to join the left leaf
2774 * of the joined buddies with its buddy at new value + 1.
2775 * we continue to join until we find a buddy that cannot be
2776 * joined (does not have a value equal to the size of the
2777 * last join) or until all leaves have been joined into a
2778 * single system.
2779 *
2780 * get the buddy size (number of words covered) of
2781 * the new value.
2782 */
2783 budsz = BUDSIZE(newval, tp->dmt_budmin);
2784
2785 /* try to join.
2786 */
2787 while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2788 /* get the buddy leaf.
2789 */
2790 buddy = leafno ^ budsz;
2791
2792 /* if the leaf's new value is greater than its
2793 * buddy's value, we join no more.
2794 */
2795 if (newval > leaf[buddy])
2796 break;
2797
2798 /* It shouldn't be less */
2799 if (newval < leaf[buddy])
2800 return -EIO;
2801
2802 /* check which (leafno or buddy) is the left buddy.
2803 * the left buddy gets to claim the blocks resulting
2804 * from the join while the right gets to claim none.
2805 * the left buddy is also eligible to participate in
2806 * a join at the next higher level while the right
2807 * is not.
2808 *
2809 */
2810 if (leafno < buddy) {
2811 /* leafno is the left buddy.
2812 */
2813 dbAdjTree(tp, buddy, NOFREE, is_ctl);
2814 } else {
2815 /* buddy is the left buddy and becomes
2816 * leafno.
2817 */
2818 dbAdjTree(tp, leafno, NOFREE, is_ctl);
2819 leafno = buddy;
2820 }
2821
2822 /* on to try the next join.
2823 */
2824 newval += 1;
2825 budsz <<= 1;
2826 }
2827 }
2828
2829 /* update the leaf value.
2830 */
2831 dbAdjTree(tp, leafno, newval, is_ctl);
2832
2833 return 0;
2834 }
2835
2836
2837 /*
2838 * NAME: dbAdjTree()
2839 *
2840 * FUNCTION: update a leaf of a dmtree with a new value, adjusting
2841 * the dmtree, as required, to reflect the new leaf value.
2842 * the combination of any buddies must already be done before
2843 * this is called.
2844 *
2845 * PARAMETERS:
2846 * tp - pointer to the tree to be adjusted.
2847 * leafno - the number of the leaf to be updated.
2848 * newval - the new value for the leaf.
2849 *
2850 * RETURN VALUES: none
2851 */
dbAdjTree(dmtree_t * tp,int leafno,int newval,bool is_ctl)2852 static void dbAdjTree(dmtree_t *tp, int leafno, int newval, bool is_ctl)
2853 {
2854 int lp, pp, k;
2855 int max, size;
2856
2857 size = is_ctl ? CTLTREESIZE : TREESIZE;
2858
2859 /* pick up the index of the leaf for this leafno.
2860 */
2861 lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2862
2863 if (WARN_ON_ONCE(lp >= size || lp < 0))
2864 return;
2865
2866 /* is the current value the same as the old value ? if so,
2867 * there is nothing to do.
2868 */
2869 if (tp->dmt_stree[lp] == newval)
2870 return;
2871
2872 /* set the new value.
2873 */
2874 tp->dmt_stree[lp] = newval;
2875
2876 /* bubble the new value up the tree as required.
2877 */
2878 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2879 if (lp == 0)
2880 break;
2881
2882 /* get the index of the first leaf of the 4 leaf
2883 * group containing the specified leaf (leafno).
2884 */
2885 lp = ((lp - 1) & ~0x03) + 1;
2886
2887 /* get the index of the parent of this 4 leaf group.
2888 */
2889 pp = (lp - 1) >> 2;
2890
2891 /* determine the maximum of the 4 leaves.
2892 */
2893 max = TREEMAX(&tp->dmt_stree[lp]);
2894
2895 /* if the maximum of the 4 is the same as the
2896 * parent's value, we're done.
2897 */
2898 if (tp->dmt_stree[pp] == max)
2899 break;
2900
2901 /* parent gets new value.
2902 */
2903 tp->dmt_stree[pp] = max;
2904
2905 /* parent becomes leaf for next go-round.
2906 */
2907 lp = pp;
2908 }
2909 }
2910
2911
2912 /*
2913 * NAME: dbFindLeaf()
2914 *
2915 * FUNCTION: search a dmtree_t for sufficient free blocks, returning
2916 * the index of a leaf describing the free blocks if
2917 * sufficient free blocks are found.
2918 *
2919 * the search starts at the top of the dmtree_t tree and
2920 * proceeds down the tree to the leftmost leaf with sufficient
2921 * free space.
2922 *
2923 * PARAMETERS:
2924 * tp - pointer to the tree to be searched.
2925 * l2nb - log2 number of free blocks to search for.
2926 * leafidx - return pointer to be set to the index of the leaf
2927 * describing at least l2nb free blocks if sufficient
2928 * free blocks are found.
2929 * is_ctl - determines if the tree is of type ctl
2930 *
2931 * RETURN VALUES:
2932 * 0 - success
2933 * -ENOSPC - insufficient free blocks.
2934 */
dbFindLeaf(dmtree_t * tp,int l2nb,int * leafidx,bool is_ctl)2935 static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl)
2936 {
2937 int ti, n = 0, k, x = 0;
2938 int max_size, max_idx;
2939
2940 max_size = is_ctl ? CTLTREESIZE : TREESIZE;
2941 max_idx = is_ctl ? LPERCTL : LPERDMAP;
2942
2943 /* first check the root of the tree to see if there is
2944 * sufficient free space.
2945 */
2946 if (l2nb > tp->dmt_stree[ROOT])
2947 return -ENOSPC;
2948
2949 /* sufficient free space available. now search down the tree
2950 * starting at the next level for the leftmost leaf that
2951 * describes sufficient free space.
2952 */
2953 for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2954 k > 0; k--, ti = ((ti + n) << 2) + 1) {
2955 /* search the four nodes at this level, starting from
2956 * the left.
2957 */
2958 for (x = ti, n = 0; n < 4; n++) {
2959 /* sufficient free space found. move to the next
2960 * level (or quit if this is the last level).
2961 */
2962 if (x + n > max_size)
2963 return -ENOSPC;
2964 if (l2nb <= tp->dmt_stree[x + n])
2965 break;
2966 }
2967
2968 /* better have found something since the higher
2969 * levels of the tree said it was here.
2970 */
2971 assert(n < 4);
2972 }
2973 if (le32_to_cpu(tp->dmt_leafidx) >= max_idx)
2974 return -ENOSPC;
2975
2976 /* set the return to the leftmost leaf describing sufficient
2977 * free space.
2978 */
2979 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2980
2981 return (0);
2982 }
2983
2984
2985 /*
2986 * NAME: dbFindBits()
2987 *
2988 * FUNCTION: find a specified number of binary buddy free bits within a
2989 * dmap bitmap word value.
2990 *
2991 * this routine searches the bitmap value for (1 << l2nb) free
2992 * bits at (1 << l2nb) alignments within the value.
2993 *
2994 * PARAMETERS:
2995 * word - dmap bitmap word value.
2996 * l2nb - number of free bits specified as a log2 number.
2997 *
2998 * RETURN VALUES:
2999 * starting bit number of free bits.
3000 */
dbFindBits(u32 word,int l2nb)3001 static int dbFindBits(u32 word, int l2nb)
3002 {
3003 int bitno, nb;
3004 u32 mask;
3005
3006 /* get the number of bits.
3007 */
3008 nb = 1 << l2nb;
3009 assert(nb <= DBWORD);
3010
3011 /* complement the word so we can use a mask (i.e. 0s represent
3012 * free bits) and compute the mask.
3013 */
3014 word = ~word;
3015 mask = ONES << (DBWORD - nb);
3016
3017 /* scan the word for nb free bits at nb alignments.
3018 */
3019 for (bitno = 0; mask != 0; bitno += nb, mask = (mask >> nb)) {
3020 if ((mask & word) == mask)
3021 break;
3022 }
3023
3024 ASSERT(bitno < 32);
3025
3026 /* return the bit number.
3027 */
3028 return (bitno);
3029 }
3030
3031
3032 /*
3033 * NAME: dbMaxBud(u8 *cp)
3034 *
3035 * FUNCTION: determine the largest binary buddy string of free
3036 * bits within 32-bits of the map.
3037 *
3038 * PARAMETERS:
3039 * cp - pointer to the 32-bit value.
3040 *
3041 * RETURN VALUES:
3042 * largest binary buddy of free bits within a dmap word.
3043 */
dbMaxBud(u8 * cp)3044 static int dbMaxBud(u8 * cp)
3045 {
3046 signed char tmp1, tmp2;
3047
3048 /* check if the wmap word is all free. if so, the
3049 * free buddy size is BUDMIN.
3050 */
3051 if (*((uint *) cp) == 0)
3052 return (BUDMIN);
3053
3054 /* check if the wmap word is half free. if so, the
3055 * free buddy size is BUDMIN-1.
3056 */
3057 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
3058 return (BUDMIN - 1);
3059
3060 /* not all free or half free. determine the free buddy
3061 * size thru table lookup using quarters of the wmap word.
3062 */
3063 tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
3064 tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
3065 return (max(tmp1, tmp2));
3066 }
3067
3068
3069 /*
3070 * NAME: cnttz(uint word)
3071 *
3072 * FUNCTION: determine the number of trailing zeros within a 32-bit
3073 * value.
3074 *
3075 * PARAMETERS:
3076 * value - 32-bit value to be examined.
3077 *
3078 * RETURN VALUES:
3079 * count of trailing zeros
3080 */
cnttz(u32 word)3081 static int cnttz(u32 word)
3082 {
3083 int n;
3084
3085 for (n = 0; n < 32; n++, word >>= 1) {
3086 if (word & 0x01)
3087 break;
3088 }
3089
3090 return (n);
3091 }
3092
3093
3094 /*
3095 * NAME: cntlz(u32 value)
3096 *
3097 * FUNCTION: determine the number of leading zeros within a 32-bit
3098 * value.
3099 *
3100 * PARAMETERS:
3101 * value - 32-bit value to be examined.
3102 *
3103 * RETURN VALUES:
3104 * count of leading zeros
3105 */
cntlz(u32 value)3106 static int cntlz(u32 value)
3107 {
3108 int n;
3109
3110 for (n = 0; n < 32; n++, value <<= 1) {
3111 if (value & HIGHORDER)
3112 break;
3113 }
3114 return (n);
3115 }
3116
3117
3118 /*
3119 * NAME: blkstol2(s64 nb)
3120 *
3121 * FUNCTION: convert a block count to its log2 value. if the block
3122 * count is not a l2 multiple, it is rounded up to the next
3123 * larger l2 multiple.
3124 *
3125 * PARAMETERS:
3126 * nb - number of blocks
3127 *
3128 * RETURN VALUES:
3129 * log2 number of blocks
3130 */
blkstol2(s64 nb)3131 static int blkstol2(s64 nb)
3132 {
3133 int l2nb;
3134 s64 mask; /* meant to be signed */
3135
3136 mask = (s64) 1 << (64 - 1);
3137
3138 /* count the leading bits.
3139 */
3140 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3141 /* leading bit found.
3142 */
3143 if (nb & mask) {
3144 /* determine the l2 value.
3145 */
3146 l2nb = (64 - 1) - l2nb;
3147
3148 /* check if we need to round up.
3149 */
3150 if (~mask & nb)
3151 l2nb++;
3152
3153 return (l2nb);
3154 }
3155 }
3156 assert(0);
3157 return 0; /* fix compiler warning */
3158 }
3159
3160
3161 /*
3162 * NAME: dbAllocBottomUp()
3163 *
3164 * FUNCTION: alloc the specified block range from the working block
3165 * allocation map.
3166 *
3167 * the blocks will be alloc from the working map one dmap
3168 * at a time.
3169 *
3170 * PARAMETERS:
3171 * ip - pointer to in-core inode;
3172 * blkno - starting block number to be freed.
3173 * nblocks - number of blocks to be freed.
3174 *
3175 * RETURN VALUES:
3176 * 0 - success
3177 * -EIO - i/o error
3178 */
dbAllocBottomUp(struct inode * ip,s64 blkno,s64 nblocks)3179 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3180 {
3181 struct metapage *mp;
3182 struct dmap *dp;
3183 int nb, rc;
3184 s64 lblkno, rem;
3185 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3186 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3187
3188 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3189
3190 /* block to be allocated better be within the mapsize. */
3191 ASSERT(nblocks <= bmp->db_mapsize - blkno);
3192
3193 /*
3194 * allocate the blocks a dmap at a time.
3195 */
3196 mp = NULL;
3197 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3198 /* release previous dmap if any */
3199 if (mp) {
3200 write_metapage(mp);
3201 }
3202
3203 /* get the buffer for the current dmap. */
3204 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3205 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3206 if (mp == NULL) {
3207 IREAD_UNLOCK(ipbmap);
3208 return -EIO;
3209 }
3210 dp = (struct dmap *) mp->data;
3211
3212 /* determine the number of blocks to be allocated from
3213 * this dmap.
3214 */
3215 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3216
3217 /* allocate the blocks. */
3218 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3219 release_metapage(mp);
3220 IREAD_UNLOCK(ipbmap);
3221 return (rc);
3222 }
3223 }
3224
3225 /* write the last buffer. */
3226 write_metapage(mp);
3227
3228 IREAD_UNLOCK(ipbmap);
3229
3230 return (0);
3231 }
3232
3233
dbAllocDmapBU(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)3234 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3235 int nblocks)
3236 {
3237 int rc;
3238 int dbitno, word, rembits, nb, nwords, wbitno, agno;
3239 s8 oldroot;
3240 struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3241
3242 /* save the current value of the root (i.e. maximum free string)
3243 * of the dmap tree.
3244 */
3245 oldroot = tp->stree[ROOT];
3246
3247 /* determine the bit number and word within the dmap of the
3248 * starting block.
3249 */
3250 dbitno = blkno & (BPERDMAP - 1);
3251 word = dbitno >> L2DBWORD;
3252
3253 /* block range better be within the dmap */
3254 assert(dbitno + nblocks <= BPERDMAP);
3255
3256 /* allocate the bits of the dmap's words corresponding to the block
3257 * range. not all bits of the first and last words may be contained
3258 * within the block range. if this is the case, we'll work against
3259 * those words (i.e. partial first and/or last) on an individual basis
3260 * (a single pass), allocating the bits of interest by hand and
3261 * updating the leaf corresponding to the dmap word. a single pass
3262 * will be used for all dmap words fully contained within the
3263 * specified range. within this pass, the bits of all fully contained
3264 * dmap words will be marked as free in a single shot and the leaves
3265 * will be updated. a single leaf may describe the free space of
3266 * multiple dmap words, so we may update only a subset of the actual
3267 * leaves corresponding to the dmap words of the block range.
3268 */
3269 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3270 /* determine the bit number within the word and
3271 * the number of bits within the word.
3272 */
3273 wbitno = dbitno & (DBWORD - 1);
3274 nb = min(rembits, DBWORD - wbitno);
3275
3276 /* check if only part of a word is to be allocated.
3277 */
3278 if (nb < DBWORD) {
3279 /* allocate (set to 1) the appropriate bits within
3280 * this dmap word.
3281 */
3282 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3283 >> wbitno);
3284
3285 word++;
3286 } else {
3287 /* one or more dmap words are fully contained
3288 * within the block range. determine how many
3289 * words and allocate (set to 1) the bits of these
3290 * words.
3291 */
3292 nwords = rembits >> L2DBWORD;
3293 memset(&dp->wmap[word], (int) ONES, nwords * 4);
3294
3295 /* determine how many bits */
3296 nb = nwords << L2DBWORD;
3297 word += nwords;
3298 }
3299 }
3300
3301 /* update the free count for this dmap */
3302 le32_add_cpu(&dp->nfree, -nblocks);
3303
3304 /* reconstruct summary tree */
3305 dbInitDmapTree(dp);
3306
3307 BMAP_LOCK(bmp);
3308
3309 /* if this allocation group is completely free,
3310 * update the highest active allocation group number
3311 * if this allocation group is the new max.
3312 */
3313 agno = blkno >> bmp->db_agl2size;
3314 if (agno > bmp->db_maxag)
3315 bmp->db_maxag = agno;
3316
3317 /* update the free count for the allocation group and map */
3318 bmp->db_agfree[agno] -= nblocks;
3319 bmp->db_nfree -= nblocks;
3320
3321 BMAP_UNLOCK(bmp);
3322
3323 /* if the root has not changed, done. */
3324 if (tp->stree[ROOT] == oldroot)
3325 return (0);
3326
3327 /* root changed. bubble the change up to the dmap control pages.
3328 * if the adjustment of the upper level control pages fails,
3329 * backout the bit allocation (thus making everything consistent).
3330 */
3331 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3332 dbFreeBits(bmp, dp, blkno, nblocks);
3333
3334 return (rc);
3335 }
3336
3337
3338 /*
3339 * NAME: dbExtendFS()
3340 *
3341 * FUNCTION: extend bmap from blkno for nblocks;
3342 * dbExtendFS() updates bmap ready for dbAllocBottomUp();
3343 *
3344 * L2
3345 * |
3346 * L1---------------------------------L1
3347 * | |
3348 * L0---------L0---------L0 L0---------L0---------L0
3349 * | | | | | |
3350 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
3351 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3352 *
3353 * <---old---><----------------------------extend----------------------->
3354 */
dbExtendFS(struct inode * ipbmap,s64 blkno,s64 nblocks)3355 int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3356 {
3357 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3358 int nbperpage = sbi->nbperpage;
3359 int i, i0 = true, j, j0 = true, k, n;
3360 s64 newsize;
3361 s64 p;
3362 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3363 struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3364 struct dmap *dp;
3365 s8 *l0leaf, *l1leaf, *l2leaf;
3366 struct bmap *bmp = sbi->bmap;
3367 int agno, l2agsize, oldl2agsize;
3368 s64 ag_rem;
3369
3370 newsize = blkno + nblocks;
3371
3372 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3373 (long long) blkno, (long long) nblocks, (long long) newsize);
3374
3375 /*
3376 * initialize bmap control page.
3377 *
3378 * all the data in bmap control page should exclude
3379 * the mkfs hidden dmap page.
3380 */
3381
3382 /* update mapsize */
3383 bmp->db_mapsize = newsize;
3384 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3385
3386 /* compute new AG size */
3387 l2agsize = dbGetL2AGSize(newsize);
3388 oldl2agsize = bmp->db_agl2size;
3389
3390 bmp->db_agl2size = l2agsize;
3391 bmp->db_agsize = (s64)1 << l2agsize;
3392
3393 /* compute new number of AG */
3394 agno = bmp->db_numag;
3395 bmp->db_numag = newsize >> l2agsize;
3396 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3397
3398 /*
3399 * reconfigure db_agfree[]
3400 * from old AG configuration to new AG configuration;
3401 *
3402 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3403 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3404 * note: new AG size = old AG size * (2**x).
3405 */
3406 if (l2agsize == oldl2agsize)
3407 goto extend;
3408 k = 1 << (l2agsize - oldl2agsize);
3409 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
3410 for (i = 0, n = 0; i < agno; n++) {
3411 bmp->db_agfree[n] = 0; /* init collection point */
3412
3413 /* coalesce contiguous k AGs; */
3414 for (j = 0; j < k && i < agno; j++, i++) {
3415 /* merge AGi to AGn */
3416 bmp->db_agfree[n] += bmp->db_agfree[i];
3417 }
3418 }
3419 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
3420
3421 for (; n < MAXAG; n++)
3422 bmp->db_agfree[n] = 0;
3423
3424 /*
3425 * update highest active ag number
3426 */
3427
3428 bmp->db_maxag = bmp->db_maxag / k;
3429
3430 /*
3431 * extend bmap
3432 *
3433 * update bit maps and corresponding level control pages;
3434 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3435 */
3436 extend:
3437 /* get L2 page */
3438 p = BMAPBLKNO + nbperpage; /* L2 page */
3439 l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3440 if (!l2mp) {
3441 jfs_error(ipbmap->i_sb, "L2 page could not be read\n");
3442 return -EIO;
3443 }
3444 l2dcp = (struct dmapctl *) l2mp->data;
3445
3446 /* compute start L1 */
3447 k = blkno >> L2MAXL1SIZE;
3448 l2leaf = l2dcp->stree + CTLLEAFIND + k;
3449 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
3450
3451 /*
3452 * extend each L1 in L2
3453 */
3454 for (; k < LPERCTL; k++, p += nbperpage) {
3455 /* get L1 page */
3456 if (j0) {
3457 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3458 l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3459 if (l1mp == NULL)
3460 goto errout;
3461 l1dcp = (struct dmapctl *) l1mp->data;
3462
3463 /* compute start L0 */
3464 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3465 l1leaf = l1dcp->stree + CTLLEAFIND + j;
3466 p = BLKTOL0(blkno, sbi->l2nbperpage);
3467 j0 = false;
3468 } else {
3469 /* assign/init L1 page */
3470 l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3471 if (l1mp == NULL)
3472 goto errout;
3473
3474 l1dcp = (struct dmapctl *) l1mp->data;
3475
3476 /* compute start L0 */
3477 j = 0;
3478 l1leaf = l1dcp->stree + CTLLEAFIND;
3479 p += nbperpage; /* 1st L0 of L1.k */
3480 }
3481
3482 /*
3483 * extend each L0 in L1
3484 */
3485 for (; j < LPERCTL; j++) {
3486 /* get L0 page */
3487 if (i0) {
3488 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3489
3490 l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3491 if (l0mp == NULL)
3492 goto errout;
3493 l0dcp = (struct dmapctl *) l0mp->data;
3494
3495 /* compute start dmap */
3496 i = (blkno & (MAXL0SIZE - 1)) >>
3497 L2BPERDMAP;
3498 l0leaf = l0dcp->stree + CTLLEAFIND + i;
3499 p = BLKTODMAP(blkno,
3500 sbi->l2nbperpage);
3501 i0 = false;
3502 } else {
3503 /* assign/init L0 page */
3504 l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3505 if (l0mp == NULL)
3506 goto errout;
3507
3508 l0dcp = (struct dmapctl *) l0mp->data;
3509
3510 /* compute start dmap */
3511 i = 0;
3512 l0leaf = l0dcp->stree + CTLLEAFIND;
3513 p += nbperpage; /* 1st dmap of L0.j */
3514 }
3515
3516 /*
3517 * extend each dmap in L0
3518 */
3519 for (; i < LPERCTL; i++) {
3520 /*
3521 * reconstruct the dmap page, and
3522 * initialize corresponding parent L0 leaf
3523 */
3524 if ((n = blkno & (BPERDMAP - 1))) {
3525 /* read in dmap page: */
3526 mp = read_metapage(ipbmap, p,
3527 PSIZE, 0);
3528 if (mp == NULL)
3529 goto errout;
3530 n = min(nblocks, (s64)BPERDMAP - n);
3531 } else {
3532 /* assign/init dmap page */
3533 mp = read_metapage(ipbmap, p,
3534 PSIZE, 0);
3535 if (mp == NULL)
3536 goto errout;
3537
3538 n = min_t(s64, nblocks, BPERDMAP);
3539 }
3540
3541 dp = (struct dmap *) mp->data;
3542 *l0leaf = dbInitDmap(dp, blkno, n);
3543
3544 bmp->db_nfree += n;
3545 agno = le64_to_cpu(dp->start) >> l2agsize;
3546 bmp->db_agfree[agno] += n;
3547
3548 write_metapage(mp);
3549
3550 l0leaf++;
3551 p += nbperpage;
3552
3553 blkno += n;
3554 nblocks -= n;
3555 if (nblocks == 0)
3556 break;
3557 } /* for each dmap in a L0 */
3558
3559 /*
3560 * build current L0 page from its leaves, and
3561 * initialize corresponding parent L1 leaf
3562 */
3563 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3564 write_metapage(l0mp);
3565 l0mp = NULL;
3566
3567 if (nblocks)
3568 l1leaf++; /* continue for next L0 */
3569 else {
3570 /* more than 1 L0 ? */
3571 if (j > 0)
3572 break; /* build L1 page */
3573 else {
3574 /* summarize in global bmap page */
3575 bmp->db_maxfreebud = *l1leaf;
3576 release_metapage(l1mp);
3577 release_metapage(l2mp);
3578 goto finalize;
3579 }
3580 }
3581 } /* for each L0 in a L1 */
3582
3583 /*
3584 * build current L1 page from its leaves, and
3585 * initialize corresponding parent L2 leaf
3586 */
3587 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3588 write_metapage(l1mp);
3589 l1mp = NULL;
3590
3591 if (nblocks)
3592 l2leaf++; /* continue for next L1 */
3593 else {
3594 /* more than 1 L1 ? */
3595 if (k > 0)
3596 break; /* build L2 page */
3597 else {
3598 /* summarize in global bmap page */
3599 bmp->db_maxfreebud = *l2leaf;
3600 release_metapage(l2mp);
3601 goto finalize;
3602 }
3603 }
3604 } /* for each L1 in a L2 */
3605
3606 jfs_error(ipbmap->i_sb, "function has not returned as expected\n");
3607 errout:
3608 if (l0mp)
3609 release_metapage(l0mp);
3610 if (l1mp)
3611 release_metapage(l1mp);
3612 release_metapage(l2mp);
3613 return -EIO;
3614
3615 /*
3616 * finalize bmap control page
3617 */
3618 finalize:
3619
3620 return 0;
3621 }
3622
3623
3624 /*
3625 * dbFinalizeBmap()
3626 */
dbFinalizeBmap(struct inode * ipbmap)3627 void dbFinalizeBmap(struct inode *ipbmap)
3628 {
3629 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3630 int actags, inactags, l2nl;
3631 s64 ag_rem, actfree, inactfree, avgfree;
3632 int i, n;
3633
3634 /*
3635 * finalize bmap control page
3636 */
3637 //finalize:
3638 /*
3639 * compute db_agpref: preferred ag to allocate from
3640 * (the leftmost ag with average free space in it);
3641 */
3642 //agpref:
3643 /* get the number of active ags and inactive ags */
3644 actags = bmp->db_maxag + 1;
3645 inactags = bmp->db_numag - actags;
3646 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
3647
3648 /* determine how many blocks are in the inactive allocation
3649 * groups. in doing this, we must account for the fact that
3650 * the rightmost group might be a partial group (i.e. file
3651 * system size is not a multiple of the group size).
3652 */
3653 inactfree = (inactags && ag_rem) ?
3654 (((s64)inactags - 1) << bmp->db_agl2size) + ag_rem
3655 : ((s64)inactags << bmp->db_agl2size);
3656
3657 /* determine how many free blocks are in the active
3658 * allocation groups plus the average number of free blocks
3659 * within the active ags.
3660 */
3661 actfree = bmp->db_nfree - inactfree;
3662 avgfree = (u32) actfree / (u32) actags;
3663
3664 /* if the preferred allocation group has not average free space.
3665 * re-establish the preferred group as the leftmost
3666 * group with average free space.
3667 */
3668 if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3669 for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3670 bmp->db_agpref++) {
3671 if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3672 break;
3673 }
3674 if (bmp->db_agpref >= bmp->db_numag) {
3675 jfs_error(ipbmap->i_sb,
3676 "cannot find ag with average freespace\n");
3677 }
3678 }
3679
3680 /*
3681 * compute db_aglevel, db_agheight, db_width, db_agstart:
3682 * an ag is covered in aglevel dmapctl summary tree,
3683 * at agheight level height (from leaf) with agwidth number of nodes
3684 * each, which starts at agstart index node of the smmary tree node
3685 * array;
3686 */
3687 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3688 l2nl =
3689 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3690 bmp->db_agheight = l2nl >> 1;
3691 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3692 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3693 i--) {
3694 bmp->db_agstart += n;
3695 n <<= 2;
3696 }
3697
3698 }
3699
3700
3701 /*
3702 * NAME: dbInitDmap()/ujfs_idmap_page()
3703 *
3704 * FUNCTION: initialize working/persistent bitmap of the dmap page
3705 * for the specified number of blocks:
3706 *
3707 * at entry, the bitmaps had been initialized as free (ZEROS);
3708 * The number of blocks will only account for the actually
3709 * existing blocks. Blocks which don't actually exist in
3710 * the aggregate will be marked as allocated (ONES);
3711 *
3712 * PARAMETERS:
3713 * dp - pointer to page of map
3714 * nblocks - number of blocks this page
3715 *
3716 * RETURNS: NONE
3717 */
dbInitDmap(struct dmap * dp,s64 Blkno,int nblocks)3718 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3719 {
3720 int blkno, w, b, r, nw, nb, i;
3721
3722 /* starting block number within the dmap */
3723 blkno = Blkno & (BPERDMAP - 1);
3724
3725 if (blkno == 0) {
3726 dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3727 dp->start = cpu_to_le64(Blkno);
3728
3729 if (nblocks == BPERDMAP) {
3730 memset(&dp->wmap[0], 0, LPERDMAP * 4);
3731 memset(&dp->pmap[0], 0, LPERDMAP * 4);
3732 goto initTree;
3733 }
3734 } else {
3735 le32_add_cpu(&dp->nblocks, nblocks);
3736 le32_add_cpu(&dp->nfree, nblocks);
3737 }
3738
3739 /* word number containing start block number */
3740 w = blkno >> L2DBWORD;
3741
3742 /*
3743 * free the bits corresponding to the block range (ZEROS):
3744 * note: not all bits of the first and last words may be contained
3745 * within the block range.
3746 */
3747 for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3748 /* number of bits preceding range to be freed in the word */
3749 b = blkno & (DBWORD - 1);
3750 /* number of bits to free in the word */
3751 nb = min(r, DBWORD - b);
3752
3753 /* is partial word to be freed ? */
3754 if (nb < DBWORD) {
3755 /* free (set to 0) from the bitmap word */
3756 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3757 >> b));
3758 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3759 >> b));
3760
3761 /* skip the word freed */
3762 w++;
3763 } else {
3764 /* free (set to 0) contiguous bitmap words */
3765 nw = r >> L2DBWORD;
3766 memset(&dp->wmap[w], 0, nw * 4);
3767 memset(&dp->pmap[w], 0, nw * 4);
3768
3769 /* skip the words freed */
3770 nb = nw << L2DBWORD;
3771 w += nw;
3772 }
3773 }
3774
3775 /*
3776 * mark bits following the range to be freed (non-existing
3777 * blocks) as allocated (ONES)
3778 */
3779
3780 if (blkno == BPERDMAP)
3781 goto initTree;
3782
3783 /* the first word beyond the end of existing blocks */
3784 w = blkno >> L2DBWORD;
3785
3786 /* does nblocks fall on a 32-bit boundary ? */
3787 b = blkno & (DBWORD - 1);
3788 if (b) {
3789 /* mark a partial word allocated */
3790 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3791 w++;
3792 }
3793
3794 /* set the rest of the words in the page to allocated (ONES) */
3795 for (i = w; i < LPERDMAP; i++)
3796 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3797
3798 /*
3799 * init tree
3800 */
3801 initTree:
3802 return (dbInitDmapTree(dp));
3803 }
3804
3805
3806 /*
3807 * NAME: dbInitDmapTree()/ujfs_complete_dmap()
3808 *
3809 * FUNCTION: initialize summary tree of the specified dmap:
3810 *
3811 * at entry, bitmap of the dmap has been initialized;
3812 *
3813 * PARAMETERS:
3814 * dp - dmap to complete
3815 * blkno - starting block number for this dmap
3816 * treemax - will be filled in with max free for this dmap
3817 *
3818 * RETURNS: max free string at the root of the tree
3819 */
dbInitDmapTree(struct dmap * dp)3820 static int dbInitDmapTree(struct dmap * dp)
3821 {
3822 struct dmaptree *tp;
3823 s8 *cp;
3824 int i;
3825
3826 /* init fixed info of tree */
3827 tp = &dp->tree;
3828 tp->nleafs = cpu_to_le32(LPERDMAP);
3829 tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3830 tp->leafidx = cpu_to_le32(LEAFIND);
3831 tp->height = cpu_to_le32(4);
3832 tp->budmin = BUDMIN;
3833
3834 /* init each leaf from corresponding wmap word:
3835 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3836 * bitmap word are allocated.
3837 */
3838 cp = tp->stree + le32_to_cpu(tp->leafidx);
3839 for (i = 0; i < LPERDMAP; i++)
3840 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3841
3842 /* build the dmap's binary buddy summary tree */
3843 return (dbInitTree(tp));
3844 }
3845
3846
3847 /*
3848 * NAME: dbInitTree()/ujfs_adjtree()
3849 *
3850 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
3851 *
3852 * at entry, the leaves of the tree has been initialized
3853 * from corresponding bitmap word or root of summary tree
3854 * of the child control page;
3855 * configure binary buddy system at the leaf level, then
3856 * bubble up the values of the leaf nodes up the tree.
3857 *
3858 * PARAMETERS:
3859 * cp - Pointer to the root of the tree
3860 * l2leaves- Number of leaf nodes as a power of 2
3861 * l2min - Number of blocks that can be covered by a leaf
3862 * as a power of 2
3863 *
3864 * RETURNS: max free string at the root of the tree
3865 */
dbInitTree(struct dmaptree * dtp)3866 static int dbInitTree(struct dmaptree * dtp)
3867 {
3868 int l2max, l2free, bsize, nextb, i;
3869 int child, parent, nparent;
3870 s8 *tp, *cp, *cp1;
3871
3872 tp = dtp->stree;
3873
3874 /* Determine the maximum free string possible for the leaves */
3875 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3876
3877 /*
3878 * configure the leaf level into binary buddy system
3879 *
3880 * Try to combine buddies starting with a buddy size of 1
3881 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3882 * can be combined if both buddies have a maximum free of l2min;
3883 * the combination will result in the left-most buddy leaf having
3884 * a maximum free of l2min+1.
3885 * After processing all buddies for a given size, process buddies
3886 * at the next higher buddy size (i.e. current size * 2) and
3887 * the next maximum free (current free + 1).
3888 * This continues until the maximum possible buddy combination
3889 * yields maximum free.
3890 */
3891 for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3892 l2free++, bsize = nextb) {
3893 /* get next buddy size == current buddy pair size */
3894 nextb = bsize << 1;
3895
3896 /* scan each adjacent buddy pair at current buddy size */
3897 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3898 i < le32_to_cpu(dtp->nleafs);
3899 i += nextb, cp += nextb) {
3900 /* coalesce if both adjacent buddies are max free */
3901 if (*cp == l2free && *(cp + bsize) == l2free) {
3902 *cp = l2free + 1; /* left take right */
3903 *(cp + bsize) = -1; /* right give left */
3904 }
3905 }
3906 }
3907
3908 /*
3909 * bubble summary information of leaves up the tree.
3910 *
3911 * Starting at the leaf node level, the four nodes described by
3912 * the higher level parent node are compared for a maximum free and
3913 * this maximum becomes the value of the parent node.
3914 * when all lower level nodes are processed in this fashion then
3915 * move up to the next level (parent becomes a lower level node) and
3916 * continue the process for that level.
3917 */
3918 for (child = le32_to_cpu(dtp->leafidx),
3919 nparent = le32_to_cpu(dtp->nleafs) >> 2;
3920 nparent > 0; nparent >>= 2, child = parent) {
3921 /* get index of 1st node of parent level */
3922 parent = (child - 1) >> 2;
3923
3924 /* set the value of the parent node as the maximum
3925 * of the four nodes of the current level.
3926 */
3927 for (i = 0, cp = tp + child, cp1 = tp + parent;
3928 i < nparent; i++, cp += 4, cp1++)
3929 *cp1 = TREEMAX(cp);
3930 }
3931
3932 return (*tp);
3933 }
3934
3935
3936 /*
3937 * dbInitDmapCtl()
3938 *
3939 * function: initialize dmapctl page
3940 */
dbInitDmapCtl(struct dmapctl * dcp,int level,int i)3941 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3942 { /* start leaf index not covered by range */
3943 s8 *cp;
3944
3945 dcp->nleafs = cpu_to_le32(LPERCTL);
3946 dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3947 dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3948 dcp->height = cpu_to_le32(5);
3949 dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3950
3951 /*
3952 * initialize the leaves of current level that were not covered
3953 * by the specified input block range (i.e. the leaves have no
3954 * low level dmapctl or dmap).
3955 */
3956 cp = &dcp->stree[CTLLEAFIND + i];
3957 for (; i < LPERCTL; i++)
3958 *cp++ = NOFREE;
3959
3960 /* build the dmap's binary buddy summary tree */
3961 return (dbInitTree((struct dmaptree *) dcp));
3962 }
3963
3964
3965 /*
3966 * NAME: dbGetL2AGSize()/ujfs_getagl2size()
3967 *
3968 * FUNCTION: Determine log2(allocation group size) from aggregate size
3969 *
3970 * PARAMETERS:
3971 * nblocks - Number of blocks in aggregate
3972 *
3973 * RETURNS: log2(allocation group size) in aggregate blocks
3974 */
dbGetL2AGSize(s64 nblocks)3975 static int dbGetL2AGSize(s64 nblocks)
3976 {
3977 s64 sz;
3978 s64 m;
3979 int l2sz;
3980
3981 if (nblocks < BPERDMAP * MAXAG)
3982 return (L2BPERDMAP);
3983
3984 /* round up aggregate size to power of 2 */
3985 m = ((u64) 1 << (64 - 1));
3986 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3987 if (m & nblocks)
3988 break;
3989 }
3990
3991 sz = (s64) 1 << l2sz;
3992 if (sz < nblocks)
3993 l2sz += 1;
3994
3995 /* agsize = roundupSize/max_number_of_ag */
3996 return (l2sz - L2MAXAG);
3997 }
3998
3999
4000 /*
4001 * NAME: dbMapFileSizeToMapSize()
4002 *
4003 * FUNCTION: compute number of blocks the block allocation map file
4004 * can cover from the map file size;
4005 *
4006 * RETURNS: Number of blocks which can be covered by this block map file;
4007 */
4008
4009 /*
4010 * maximum number of map pages at each level including control pages
4011 */
4012 #define MAXL0PAGES (1 + LPERCTL)
4013 #define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
4014
4015 /*
4016 * convert number of map pages to the zero origin top dmapctl level
4017 */
4018 #define BMAPPGTOLEV(npages) \
4019 (((npages) <= 3 + MAXL0PAGES) ? 0 : \
4020 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
4021
dbMapFileSizeToMapSize(struct inode * ipbmap)4022 s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
4023 {
4024 struct super_block *sb = ipbmap->i_sb;
4025 s64 nblocks;
4026 s64 npages, ndmaps;
4027 int level, i;
4028 int complete, factor;
4029
4030 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
4031 npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
4032 level = BMAPPGTOLEV(npages);
4033
4034 /* At each level, accumulate the number of dmap pages covered by
4035 * the number of full child levels below it;
4036 * repeat for the last incomplete child level.
4037 */
4038 ndmaps = 0;
4039 npages--; /* skip the first global control page */
4040 /* skip higher level control pages above top level covered by map */
4041 npages -= (2 - level);
4042 npages--; /* skip top level's control page */
4043 for (i = level; i >= 0; i--) {
4044 factor =
4045 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
4046 complete = (u32) npages / factor;
4047 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
4048 ((i == 1) ? LPERCTL : 1));
4049
4050 /* pages in last/incomplete child */
4051 npages = (u32) npages % factor;
4052 /* skip incomplete child's level control page */
4053 npages--;
4054 }
4055
4056 /* convert the number of dmaps into the number of blocks
4057 * which can be covered by the dmaps;
4058 */
4059 nblocks = ndmaps << L2BPERDMAP;
4060
4061 return (nblocks);
4062 }
4063