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 */ 64static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 65 int nblocks); 66static void dbSplit(dmtree_t *tp, int leafno, int splitsz, int newval, bool is_ctl); 67static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl); 68static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl); 69static void dbAdjTree(dmtree_t *tp, int leafno, int newval, bool is_ctl); 70static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, 71 int level); 72static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results); 73static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 74 int nblocks); 75static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno, 76 int nblocks, 77 int l2nb, s64 * results); 78static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 79 int nblocks); 80static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks, 81 int l2nb, 82 s64 * results); 83static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, 84 s64 * results); 85static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, 86 s64 * results); 87static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks); 88static int dbFindBits(u32 word, int l2nb); 89static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno); 90static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl); 91static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 92 int nblocks); 93static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 94 int nblocks); 95static int dbMaxBud(u8 * cp); 96static int blkstol2(s64 nb); 97 98static int cntlz(u32 value); 99static int cnttz(u32 word); 100 101static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 102 int nblocks); 103static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks); 104static int dbInitDmapTree(struct dmap * dp); 105static int dbInitTree(struct dmaptree * dtp); 106static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i); 107static 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 */ 117static 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 */ 153int 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); 181 182 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage); 183 if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE || 184 bmp->db_l2nbperpage < 0) { 185 err = -EINVAL; 186 goto err_release_metapage; 187 } 188 189 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag); 190 if (!bmp->db_numag) { 191 err = -EINVAL; 192 goto err_release_metapage; 193 } 194 195 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); 196 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag); 197 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref); 198 if (bmp->db_maxag >= MAXAG || bmp->db_maxag < 0 || 199 bmp->db_agpref >= MAXAG || bmp->db_agpref < 0) { 200 err = -EINVAL; 201 goto err_release_metapage; 202 } 203 204 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel); 205 bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight); 206 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth); 207 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart); 208 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size); 209 if (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG || 210 bmp->db_agl2size < 0) { 211 err = -EINVAL; 212 goto err_release_metapage; 213 } 214 215 if (((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) { 216 err = -EINVAL; 217 goto err_release_metapage; 218 } 219 220 for (i = 0; i < MAXAG; i++) 221 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]); 222 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize); 223 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud; 224 225 /* release the buffer. */ 226 release_metapage(mp); 227 228 /* bind the bmap inode and the bmap descriptor to each other. */ 229 bmp->db_ipbmap = ipbmap; 230 JFS_SBI(ipbmap->i_sb)->bmap = bmp; 231 232 memset(bmp->db_active, 0, sizeof(bmp->db_active)); 233 234 /* 235 * allocate/initialize the bmap lock 236 */ 237 BMAP_LOCK_INIT(bmp); 238 239 return (0); 240 241err_release_metapage: 242 release_metapage(mp); 243err_kfree_bmp: 244 kfree(bmp); 245 return err; 246} 247 248 249/* 250 * NAME: dbUnmount() 251 * 252 * FUNCTION: terminate the block allocation map in preparation for 253 * file system unmount. 254 * 255 * the in-core bmap descriptor is written to disk and 256 * the memory for this descriptor is freed. 257 * 258 * PARAMETERS: 259 * ipbmap - pointer to in-core inode for the block map. 260 * 261 * RETURN VALUES: 262 * 0 - success 263 * -EIO - i/o error 264 */ 265int dbUnmount(struct inode *ipbmap, int mounterror) 266{ 267 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 268 269 if (!(mounterror || isReadOnly(ipbmap))) 270 dbSync(ipbmap); 271 272 /* 273 * Invalidate the page cache buffers 274 */ 275 truncate_inode_pages(ipbmap->i_mapping, 0); 276 277 /* free the memory for the in-memory bmap. */ 278 kfree(bmp); 279 JFS_SBI(ipbmap->i_sb)->bmap = NULL; 280 281 return (0); 282} 283 284/* 285 * dbSync() 286 */ 287int dbSync(struct inode *ipbmap) 288{ 289 struct dbmap_disk *dbmp_le; 290 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 291 struct metapage *mp; 292 int i; 293 294 /* 295 * write bmap global control page 296 */ 297 /* get the buffer for the on-disk bmap descriptor. */ 298 mp = read_metapage(ipbmap, 299 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage, 300 PSIZE, 0); 301 if (mp == NULL) { 302 jfs_err("dbSync: read_metapage failed!"); 303 return -EIO; 304 } 305 /* copy the in-memory version of the bmap to the on-disk version */ 306 dbmp_le = (struct dbmap_disk *) mp->data; 307 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize); 308 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree); 309 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage); 310 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag); 311 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel); 312 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag); 313 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref); 314 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel); 315 dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight); 316 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth); 317 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart); 318 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size); 319 for (i = 0; i < MAXAG; i++) 320 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]); 321 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize); 322 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud; 323 324 /* write the buffer */ 325 write_metapage(mp); 326 327 /* 328 * write out dirty pages of bmap 329 */ 330 filemap_write_and_wait(ipbmap->i_mapping); 331 332 diWriteSpecial(ipbmap, 0); 333 334 return (0); 335} 336 337/* 338 * NAME: dbFree() 339 * 340 * FUNCTION: free the specified block range from the working block 341 * allocation map. 342 * 343 * the blocks will be free from the working map one dmap 344 * at a time. 345 * 346 * PARAMETERS: 347 * ip - pointer to in-core inode; 348 * blkno - starting block number to be freed. 349 * nblocks - number of blocks to be freed. 350 * 351 * RETURN VALUES: 352 * 0 - success 353 * -EIO - i/o error 354 */ 355int dbFree(struct inode *ip, s64 blkno, s64 nblocks) 356{ 357 struct metapage *mp; 358 struct dmap *dp; 359 int nb, rc; 360 s64 lblkno, rem; 361 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 362 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 363 struct super_block *sb = ipbmap->i_sb; 364 365 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 366 367 /* block to be freed better be within the mapsize. */ 368 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) { 369 IREAD_UNLOCK(ipbmap); 370 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", 371 (unsigned long long) blkno, 372 (unsigned long long) nblocks); 373 jfs_error(ip->i_sb, "block to be freed is outside the map\n"); 374 return -EIO; 375 } 376 377 /** 378 * TRIM the blocks, when mounted with discard option 379 */ 380 if (JFS_SBI(sb)->flag & JFS_DISCARD) 381 if (JFS_SBI(sb)->minblks_trim <= nblocks) 382 jfs_issue_discard(ipbmap, blkno, nblocks); 383 384 /* 385 * free the blocks a dmap at a time. 386 */ 387 mp = NULL; 388 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 389 /* release previous dmap if any */ 390 if (mp) { 391 write_metapage(mp); 392 } 393 394 /* get the buffer for the current dmap. */ 395 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 396 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 397 if (mp == NULL) { 398 IREAD_UNLOCK(ipbmap); 399 return -EIO; 400 } 401 dp = (struct dmap *) mp->data; 402 403 /* determine the number of blocks to be freed from 404 * this dmap. 405 */ 406 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 407 408 /* free the blocks. */ 409 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) { 410 jfs_error(ip->i_sb, "error in block map\n"); 411 release_metapage(mp); 412 IREAD_UNLOCK(ipbmap); 413 return (rc); 414 } 415 } 416 417 /* write the last buffer. */ 418 if (mp) 419 write_metapage(mp); 420 421 IREAD_UNLOCK(ipbmap); 422 423 return (0); 424} 425 426 427/* 428 * NAME: dbUpdatePMap() 429 * 430 * FUNCTION: update the allocation state (free or allocate) of the 431 * specified block range in the persistent block allocation map. 432 * 433 * the blocks will be updated in the persistent map one 434 * dmap at a time. 435 * 436 * PARAMETERS: 437 * ipbmap - pointer to in-core inode for the block map. 438 * free - 'true' if block range is to be freed from the persistent 439 * map; 'false' if it is to be allocated. 440 * blkno - starting block number of the range. 441 * nblocks - number of contiguous blocks in the range. 442 * tblk - transaction block; 443 * 444 * RETURN VALUES: 445 * 0 - success 446 * -EIO - i/o error 447 */ 448int 449dbUpdatePMap(struct inode *ipbmap, 450 int free, s64 blkno, s64 nblocks, struct tblock * tblk) 451{ 452 int nblks, dbitno, wbitno, rbits; 453 int word, nbits, nwords; 454 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 455 s64 lblkno, rem, lastlblkno; 456 u32 mask; 457 struct dmap *dp; 458 struct metapage *mp; 459 struct jfs_log *log; 460 int lsn, difft, diffp; 461 unsigned long flags; 462 463 /* the blocks better be within the mapsize. */ 464 if (blkno + nblocks > bmp->db_mapsize) { 465 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", 466 (unsigned long long) blkno, 467 (unsigned long long) nblocks); 468 jfs_error(ipbmap->i_sb, "blocks are outside the map\n"); 469 return -EIO; 470 } 471 472 /* compute delta of transaction lsn from log syncpt */ 473 lsn = tblk->lsn; 474 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log; 475 logdiff(difft, lsn, log); 476 477 /* 478 * update the block state a dmap at a time. 479 */ 480 mp = NULL; 481 lastlblkno = 0; 482 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) { 483 /* get the buffer for the current dmap. */ 484 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 485 if (lblkno != lastlblkno) { 486 if (mp) { 487 write_metapage(mp); 488 } 489 490 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 491 0); 492 if (mp == NULL) 493 return -EIO; 494 metapage_wait_for_io(mp); 495 } 496 dp = (struct dmap *) mp->data; 497 498 /* determine the bit number and word within the dmap of 499 * the starting block. also determine how many blocks 500 * are to be updated within this dmap. 501 */ 502 dbitno = blkno & (BPERDMAP - 1); 503 word = dbitno >> L2DBWORD; 504 nblks = min(rem, (s64)BPERDMAP - dbitno); 505 506 /* update the bits of the dmap words. the first and last 507 * words may only have a subset of their bits updated. if 508 * this is the case, we'll work against that word (i.e. 509 * partial first and/or last) only in a single pass. a 510 * single pass will also be used to update all words that 511 * are to have all their bits updated. 512 */ 513 for (rbits = nblks; rbits > 0; 514 rbits -= nbits, dbitno += nbits) { 515 /* determine the bit number within the word and 516 * the number of bits within the word. 517 */ 518 wbitno = dbitno & (DBWORD - 1); 519 nbits = min(rbits, DBWORD - wbitno); 520 521 /* check if only part of the word is to be updated. */ 522 if (nbits < DBWORD) { 523 /* update (free or allocate) the bits 524 * in this word. 525 */ 526 mask = 527 (ONES << (DBWORD - nbits) >> wbitno); 528 if (free) 529 dp->pmap[word] &= 530 cpu_to_le32(~mask); 531 else 532 dp->pmap[word] |= 533 cpu_to_le32(mask); 534 535 word += 1; 536 } else { 537 /* one or more words are to have all 538 * their bits updated. determine how 539 * many words and how many bits. 540 */ 541 nwords = rbits >> L2DBWORD; 542 nbits = nwords << L2DBWORD; 543 544 /* update (free or allocate) the bits 545 * in these words. 546 */ 547 if (free) 548 memset(&dp->pmap[word], 0, 549 nwords * 4); 550 else 551 memset(&dp->pmap[word], (int) ONES, 552 nwords * 4); 553 554 word += nwords; 555 } 556 } 557 558 /* 559 * update dmap lsn 560 */ 561 if (lblkno == lastlblkno) 562 continue; 563 564 lastlblkno = lblkno; 565 566 LOGSYNC_LOCK(log, flags); 567 if (mp->lsn != 0) { 568 /* inherit older/smaller lsn */ 569 logdiff(diffp, mp->lsn, log); 570 if (difft < diffp) { 571 mp->lsn = lsn; 572 573 /* move bp after tblock in logsync list */ 574 list_move(&mp->synclist, &tblk->synclist); 575 } 576 577 /* inherit younger/larger clsn */ 578 logdiff(difft, tblk->clsn, log); 579 logdiff(diffp, mp->clsn, log); 580 if (difft > diffp) 581 mp->clsn = tblk->clsn; 582 } else { 583 mp->log = log; 584 mp->lsn = lsn; 585 586 /* insert bp after tblock in logsync list */ 587 log->count++; 588 list_add(&mp->synclist, &tblk->synclist); 589 590 mp->clsn = tblk->clsn; 591 } 592 LOGSYNC_UNLOCK(log, flags); 593 } 594 595 /* write the last buffer. */ 596 if (mp) { 597 write_metapage(mp); 598 } 599 600 return (0); 601} 602 603 604/* 605 * NAME: dbNextAG() 606 * 607 * FUNCTION: find the preferred allocation group for new allocations. 608 * 609 * Within the allocation groups, we maintain a preferred 610 * allocation group which consists of a group with at least 611 * average free space. It is the preferred group that we target 612 * new inode allocation towards. The tie-in between inode 613 * allocation and block allocation occurs as we allocate the 614 * first (data) block of an inode and specify the inode (block) 615 * as the allocation hint for this block. 616 * 617 * We try to avoid having more than one open file growing in 618 * an allocation group, as this will lead to fragmentation. 619 * This differs from the old OS/2 method of trying to keep 620 * empty ags around for large allocations. 621 * 622 * PARAMETERS: 623 * ipbmap - pointer to in-core inode for the block map. 624 * 625 * RETURN VALUES: 626 * the preferred allocation group number. 627 */ 628int dbNextAG(struct inode *ipbmap) 629{ 630 s64 avgfree; 631 int agpref; 632 s64 hwm = 0; 633 int i; 634 int next_best = -1; 635 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 636 637 BMAP_LOCK(bmp); 638 639 /* determine the average number of free blocks within the ags. */ 640 avgfree = (u32)bmp->db_nfree / bmp->db_numag; 641 642 /* 643 * if the current preferred ag does not have an active allocator 644 * and has at least average freespace, return it 645 */ 646 agpref = bmp->db_agpref; 647 if ((atomic_read(&bmp->db_active[agpref]) == 0) && 648 (bmp->db_agfree[agpref] >= avgfree)) 649 goto unlock; 650 651 /* From the last preferred ag, find the next one with at least 652 * average free space. 653 */ 654 for (i = 0 ; i < bmp->db_numag; i++, agpref++) { 655 if (agpref == bmp->db_numag) 656 agpref = 0; 657 658 if (atomic_read(&bmp->db_active[agpref])) 659 /* open file is currently growing in this ag */ 660 continue; 661 if (bmp->db_agfree[agpref] >= avgfree) { 662 /* Return this one */ 663 bmp->db_agpref = agpref; 664 goto unlock; 665 } else if (bmp->db_agfree[agpref] > hwm) { 666 /* Less than avg. freespace, but best so far */ 667 hwm = bmp->db_agfree[agpref]; 668 next_best = agpref; 669 } 670 } 671 672 /* 673 * If no inactive ag was found with average freespace, use the 674 * next best 675 */ 676 if (next_best != -1) 677 bmp->db_agpref = next_best; 678 /* else leave db_agpref unchanged */ 679unlock: 680 BMAP_UNLOCK(bmp); 681 682 /* return the preferred group. 683 */ 684 return (bmp->db_agpref); 685} 686 687/* 688 * NAME: dbAlloc() 689 * 690 * FUNCTION: attempt to allocate a specified number of contiguous free 691 * blocks from the working allocation block map. 692 * 693 * the block allocation policy uses hints and a multi-step 694 * approach. 695 * 696 * for allocation requests smaller than the number of blocks 697 * per dmap, we first try to allocate the new blocks 698 * immediately following the hint. if these blocks are not 699 * available, we try to allocate blocks near the hint. if 700 * no blocks near the hint are available, we next try to 701 * allocate within the same dmap as contains the hint. 702 * 703 * if no blocks are available in the dmap or the allocation 704 * request is larger than the dmap size, we try to allocate 705 * within the same allocation group as contains the hint. if 706 * this does not succeed, we finally try to allocate anywhere 707 * within the aggregate. 708 * 709 * we also try to allocate anywhere within the aggregate for 710 * for allocation requests larger than the allocation group 711 * size or requests that specify no hint value. 712 * 713 * PARAMETERS: 714 * ip - pointer to in-core inode; 715 * hint - allocation hint. 716 * nblocks - number of contiguous blocks in the range. 717 * results - on successful return, set to the starting block number 718 * of the newly allocated contiguous range. 719 * 720 * RETURN VALUES: 721 * 0 - success 722 * -ENOSPC - insufficient disk resources 723 * -EIO - i/o error 724 */ 725int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results) 726{ 727 int rc, agno; 728 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 729 struct bmap *bmp; 730 struct metapage *mp; 731 s64 lblkno, blkno; 732 struct dmap *dp; 733 int l2nb; 734 s64 mapSize; 735 int writers; 736 737 /* assert that nblocks is valid */ 738 assert(nblocks > 0); 739 740 /* get the log2 number of blocks to be allocated. 741 * if the number of blocks is not a log2 multiple, 742 * it will be rounded up to the next log2 multiple. 743 */ 744 l2nb = BLKSTOL2(nblocks); 745 746 bmp = JFS_SBI(ip->i_sb)->bmap; 747 748 mapSize = bmp->db_mapsize; 749 750 /* the hint should be within the map */ 751 if (hint >= mapSize) { 752 jfs_error(ip->i_sb, "the hint is outside the map\n"); 753 return -EIO; 754 } 755 756 /* if the number of blocks to be allocated is greater than the 757 * allocation group size, try to allocate anywhere. 758 */ 759 if (l2nb > bmp->db_agl2size) { 760 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 761 762 rc = dbAllocAny(bmp, nblocks, l2nb, results); 763 764 goto write_unlock; 765 } 766 767 /* 768 * If no hint, let dbNextAG recommend an allocation group 769 */ 770 if (hint == 0) 771 goto pref_ag; 772 773 /* we would like to allocate close to the hint. adjust the 774 * hint to the block following the hint since the allocators 775 * will start looking for free space starting at this point. 776 */ 777 blkno = hint + 1; 778 779 if (blkno >= bmp->db_mapsize) 780 goto pref_ag; 781 782 agno = blkno >> bmp->db_agl2size; 783 784 /* check if blkno crosses over into a new allocation group. 785 * if so, check if we should allow allocations within this 786 * allocation group. 787 */ 788 if ((blkno & (bmp->db_agsize - 1)) == 0) 789 /* check if the AG is currently being written to. 790 * if so, call dbNextAG() to find a non-busy 791 * AG with sufficient free space. 792 */ 793 if (atomic_read(&bmp->db_active[agno])) 794 goto pref_ag; 795 796 /* check if the allocation request size can be satisfied from a 797 * single dmap. if so, try to allocate from the dmap containing 798 * the hint using a tiered strategy. 799 */ 800 if (nblocks <= BPERDMAP) { 801 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 802 803 /* get the buffer for the dmap containing the hint. 804 */ 805 rc = -EIO; 806 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 807 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 808 if (mp == NULL) 809 goto read_unlock; 810 811 dp = (struct dmap *) mp->data; 812 813 /* first, try to satisfy the allocation request with the 814 * blocks beginning at the hint. 815 */ 816 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks)) 817 != -ENOSPC) { 818 if (rc == 0) { 819 *results = blkno; 820 mark_metapage_dirty(mp); 821 } 822 823 release_metapage(mp); 824 goto read_unlock; 825 } 826 827 writers = atomic_read(&bmp->db_active[agno]); 828 if ((writers > 1) || 829 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) { 830 /* 831 * Someone else is writing in this allocation 832 * group. To avoid fragmenting, try another ag 833 */ 834 release_metapage(mp); 835 IREAD_UNLOCK(ipbmap); 836 goto pref_ag; 837 } 838 839 /* next, try to satisfy the allocation request with blocks 840 * near the hint. 841 */ 842 if ((rc = 843 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results)) 844 != -ENOSPC) { 845 if (rc == 0) 846 mark_metapage_dirty(mp); 847 848 release_metapage(mp); 849 goto read_unlock; 850 } 851 852 /* try to satisfy the allocation request with blocks within 853 * the same dmap as the hint. 854 */ 855 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results)) 856 != -ENOSPC) { 857 if (rc == 0) 858 mark_metapage_dirty(mp); 859 860 release_metapage(mp); 861 goto read_unlock; 862 } 863 864 release_metapage(mp); 865 IREAD_UNLOCK(ipbmap); 866 } 867 868 /* try to satisfy the allocation request with blocks within 869 * the same allocation group as the hint. 870 */ 871 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 872 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC) 873 goto write_unlock; 874 875 IWRITE_UNLOCK(ipbmap); 876 877 878 pref_ag: 879 /* 880 * Let dbNextAG recommend a preferred allocation group 881 */ 882 agno = dbNextAG(ipbmap); 883 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 884 885 /* Try to allocate within this allocation group. if that fails, try to 886 * allocate anywhere in the map. 887 */ 888 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC) 889 rc = dbAllocAny(bmp, nblocks, l2nb, results); 890 891 write_unlock: 892 IWRITE_UNLOCK(ipbmap); 893 894 return (rc); 895 896 read_unlock: 897 IREAD_UNLOCK(ipbmap); 898 899 return (rc); 900} 901 902#ifdef _NOTYET 903/* 904 * NAME: dbAllocExact() 905 * 906 * FUNCTION: try to allocate the requested extent; 907 * 908 * PARAMETERS: 909 * ip - pointer to in-core inode; 910 * blkno - extent address; 911 * nblocks - extent length; 912 * 913 * RETURN VALUES: 914 * 0 - success 915 * -ENOSPC - insufficient disk resources 916 * -EIO - i/o error 917 */ 918int dbAllocExact(struct inode *ip, s64 blkno, int nblocks) 919{ 920 int rc; 921 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 922 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 923 struct dmap *dp; 924 s64 lblkno; 925 struct metapage *mp; 926 927 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 928 929 /* 930 * validate extent request: 931 * 932 * note: defragfs policy: 933 * max 64 blocks will be moved. 934 * allocation request size must be satisfied from a single dmap. 935 */ 936 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) { 937 IREAD_UNLOCK(ipbmap); 938 return -EINVAL; 939 } 940 941 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) { 942 /* the free space is no longer available */ 943 IREAD_UNLOCK(ipbmap); 944 return -ENOSPC; 945 } 946 947 /* read in the dmap covering the extent */ 948 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 949 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 950 if (mp == NULL) { 951 IREAD_UNLOCK(ipbmap); 952 return -EIO; 953 } 954 dp = (struct dmap *) mp->data; 955 956 /* try to allocate the requested extent */ 957 rc = dbAllocNext(bmp, dp, blkno, nblocks); 958 959 IREAD_UNLOCK(ipbmap); 960 961 if (rc == 0) 962 mark_metapage_dirty(mp); 963 964 release_metapage(mp); 965 966 return (rc); 967} 968#endif /* _NOTYET */ 969 970/* 971 * NAME: dbReAlloc() 972 * 973 * FUNCTION: attempt to extend a current allocation by a specified 974 * number of blocks. 975 * 976 * this routine attempts to satisfy the allocation request 977 * by first trying to extend the existing allocation in 978 * place by allocating the additional blocks as the blocks 979 * immediately following the current allocation. if these 980 * blocks are not available, this routine will attempt to 981 * allocate a new set of contiguous blocks large enough 982 * to cover the existing allocation plus the additional 983 * number of blocks required. 984 * 985 * PARAMETERS: 986 * ip - pointer to in-core inode requiring allocation. 987 * blkno - starting block of the current allocation. 988 * nblocks - number of contiguous blocks within the current 989 * allocation. 990 * addnblocks - number of blocks to add to the allocation. 991 * results - on successful return, set to the starting block number 992 * of the existing allocation if the existing allocation 993 * was extended in place or to a newly allocated contiguous 994 * range if the existing allocation could not be extended 995 * in place. 996 * 997 * RETURN VALUES: 998 * 0 - success 999 * -ENOSPC - insufficient disk resources 1000 * -EIO - i/o error 1001 */ 1002int 1003dbReAlloc(struct inode *ip, 1004 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results) 1005{ 1006 int rc; 1007 1008 /* try to extend the allocation in place. 1009 */ 1010 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) { 1011 *results = blkno; 1012 return (0); 1013 } else { 1014 if (rc != -ENOSPC) 1015 return (rc); 1016 } 1017 1018 /* could not extend the allocation in place, so allocate a 1019 * new set of blocks for the entire request (i.e. try to get 1020 * a range of contiguous blocks large enough to cover the 1021 * existing allocation plus the additional blocks.) 1022 */ 1023 return (dbAlloc 1024 (ip, blkno + nblocks - 1, addnblocks + nblocks, results)); 1025} 1026 1027 1028/* 1029 * NAME: dbExtend() 1030 * 1031 * FUNCTION: attempt to extend a current allocation by a specified 1032 * number of blocks. 1033 * 1034 * this routine attempts to satisfy the allocation request 1035 * by first trying to extend the existing allocation in 1036 * place by allocating the additional blocks as the blocks 1037 * immediately following the current allocation. 1038 * 1039 * PARAMETERS: 1040 * ip - pointer to in-core inode requiring allocation. 1041 * blkno - starting block of the current allocation. 1042 * nblocks - number of contiguous blocks within the current 1043 * allocation. 1044 * addnblocks - number of blocks to add to the allocation. 1045 * 1046 * RETURN VALUES: 1047 * 0 - success 1048 * -ENOSPC - insufficient disk resources 1049 * -EIO - i/o error 1050 */ 1051static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks) 1052{ 1053 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb); 1054 s64 lblkno, lastblkno, extblkno; 1055 uint rel_block; 1056 struct metapage *mp; 1057 struct dmap *dp; 1058 int rc; 1059 struct inode *ipbmap = sbi->ipbmap; 1060 struct bmap *bmp; 1061 1062 /* 1063 * We don't want a non-aligned extent to cross a page boundary 1064 */ 1065 if (((rel_block = blkno & (sbi->nbperpage - 1))) && 1066 (rel_block + nblocks + addnblocks > sbi->nbperpage)) 1067 return -ENOSPC; 1068 1069 /* get the last block of the current allocation */ 1070 lastblkno = blkno + nblocks - 1; 1071 1072 /* determine the block number of the block following 1073 * the existing allocation. 1074 */ 1075 extblkno = lastblkno + 1; 1076 1077 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 1078 1079 /* better be within the file system */ 1080 bmp = sbi->bmap; 1081 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) { 1082 IREAD_UNLOCK(ipbmap); 1083 jfs_error(ip->i_sb, "the block is outside the filesystem\n"); 1084 return -EIO; 1085 } 1086 1087 /* we'll attempt to extend the current allocation in place by 1088 * allocating the additional blocks as the blocks immediately 1089 * following the current allocation. we only try to extend the 1090 * current allocation in place if the number of additional blocks 1091 * can fit into a dmap, the last block of the current allocation 1092 * is not the last block of the file system, and the start of the 1093 * inplace extension is not on an allocation group boundary. 1094 */ 1095 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize || 1096 (extblkno & (bmp->db_agsize - 1)) == 0) { 1097 IREAD_UNLOCK(ipbmap); 1098 return -ENOSPC; 1099 } 1100 1101 /* get the buffer for the dmap containing the first block 1102 * of the extension. 1103 */ 1104 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage); 1105 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 1106 if (mp == NULL) { 1107 IREAD_UNLOCK(ipbmap); 1108 return -EIO; 1109 } 1110 1111 dp = (struct dmap *) mp->data; 1112 1113 /* try to allocate the blocks immediately following the 1114 * current allocation. 1115 */ 1116 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks); 1117 1118 IREAD_UNLOCK(ipbmap); 1119 1120 /* were we successful ? */ 1121 if (rc == 0) 1122 write_metapage(mp); 1123 else 1124 /* we were not successful */ 1125 release_metapage(mp); 1126 1127 return (rc); 1128} 1129 1130 1131/* 1132 * NAME: dbAllocNext() 1133 * 1134 * FUNCTION: attempt to allocate the blocks of the specified block 1135 * range within a dmap. 1136 * 1137 * PARAMETERS: 1138 * bmp - pointer to bmap descriptor 1139 * dp - pointer to dmap. 1140 * blkno - starting block number of the range. 1141 * nblocks - number of contiguous free blocks of the range. 1142 * 1143 * RETURN VALUES: 1144 * 0 - success 1145 * -ENOSPC - insufficient disk resources 1146 * -EIO - i/o error 1147 * 1148 * serialization: IREAD_LOCK(ipbmap) held on entry/exit; 1149 */ 1150static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 1151 int nblocks) 1152{ 1153 int dbitno, word, rembits, nb, nwords, wbitno, nw; 1154 int l2size; 1155 s8 *leaf; 1156 u32 mask; 1157 1158 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { 1159 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); 1160 return -EIO; 1161 } 1162 1163 /* pick up a pointer to the leaves of the dmap tree. 1164 */ 1165 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx); 1166 1167 /* determine the bit number and word within the dmap of the 1168 * starting block. 1169 */ 1170 dbitno = blkno & (BPERDMAP - 1); 1171 word = dbitno >> L2DBWORD; 1172 1173 /* check if the specified block range is contained within 1174 * this dmap. 1175 */ 1176 if (dbitno + nblocks > BPERDMAP) 1177 return -ENOSPC; 1178 1179 /* check if the starting leaf indicates that anything 1180 * is free. 1181 */ 1182 if (leaf[word] == NOFREE) 1183 return -ENOSPC; 1184 1185 /* check the dmaps words corresponding to block range to see 1186 * if the block range is free. not all bits of the first and 1187 * last words may be contained within the block range. if this 1188 * is the case, we'll work against those words (i.e. partial first 1189 * and/or last) on an individual basis (a single pass) and examine 1190 * the actual bits to determine if they are free. a single pass 1191 * will be used for all dmap words fully contained within the 1192 * specified range. within this pass, the leaves of the dmap 1193 * tree will be examined to determine if the blocks are free. a 1194 * single leaf may describe the free space of multiple dmap 1195 * words, so we may visit only a subset of the actual leaves 1196 * corresponding to the dmap words of the block range. 1197 */ 1198 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 1199 /* determine the bit number within the word and 1200 * the number of bits within the word. 1201 */ 1202 wbitno = dbitno & (DBWORD - 1); 1203 nb = min(rembits, DBWORD - wbitno); 1204 1205 /* check if only part of the word is to be examined. 1206 */ 1207 if (nb < DBWORD) { 1208 /* check if the bits are free. 1209 */ 1210 mask = (ONES << (DBWORD - nb) >> wbitno); 1211 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask) 1212 return -ENOSPC; 1213 1214 word += 1; 1215 } else { 1216 /* one or more dmap words are fully contained 1217 * within the block range. determine how many 1218 * words and how many bits. 1219 */ 1220 nwords = rembits >> L2DBWORD; 1221 nb = nwords << L2DBWORD; 1222 1223 /* now examine the appropriate leaves to determine 1224 * if the blocks are free. 1225 */ 1226 while (nwords > 0) { 1227 /* does the leaf describe any free space ? 1228 */ 1229 if (leaf[word] < BUDMIN) 1230 return -ENOSPC; 1231 1232 /* determine the l2 number of bits provided 1233 * by this leaf. 1234 */ 1235 l2size = 1236 min_t(int, leaf[word], NLSTOL2BSZ(nwords)); 1237 1238 /* determine how many words were handled. 1239 */ 1240 nw = BUDSIZE(l2size, BUDMIN); 1241 1242 nwords -= nw; 1243 word += nw; 1244 } 1245 } 1246 } 1247 1248 /* allocate the blocks. 1249 */ 1250 return (dbAllocDmap(bmp, dp, blkno, nblocks)); 1251} 1252 1253 1254/* 1255 * NAME: dbAllocNear() 1256 * 1257 * FUNCTION: attempt to allocate a number of contiguous free blocks near 1258 * a specified block (hint) within a dmap. 1259 * 1260 * starting with the dmap leaf that covers the hint, we'll 1261 * check the next four contiguous leaves for sufficient free 1262 * space. if sufficient free space is found, we'll allocate 1263 * the desired free space. 1264 * 1265 * PARAMETERS: 1266 * bmp - pointer to bmap descriptor 1267 * dp - pointer to dmap. 1268 * blkno - block number to allocate near. 1269 * nblocks - actual number of contiguous free blocks desired. 1270 * l2nb - log2 number of contiguous free blocks desired. 1271 * results - on successful return, set to the starting block number 1272 * of the newly allocated range. 1273 * 1274 * RETURN VALUES: 1275 * 0 - success 1276 * -ENOSPC - insufficient disk resources 1277 * -EIO - i/o error 1278 * 1279 * serialization: IREAD_LOCK(ipbmap) held on entry/exit; 1280 */ 1281static int 1282dbAllocNear(struct bmap * bmp, 1283 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results) 1284{ 1285 int word, lword, rc; 1286 s8 *leaf; 1287 1288 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { 1289 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); 1290 return -EIO; 1291 } 1292 1293 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx); 1294 1295 /* determine the word within the dmap that holds the hint 1296 * (i.e. blkno). also, determine the last word in the dmap 1297 * that we'll include in our examination. 1298 */ 1299 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 1300 lword = min(word + 4, LPERDMAP); 1301 1302 /* examine the leaves for sufficient free space. 1303 */ 1304 for (; word < lword; word++) { 1305 /* does the leaf describe sufficient free space ? 1306 */ 1307 if (leaf[word] < l2nb) 1308 continue; 1309 1310 /* determine the block number within the file system 1311 * of the first block described by this dmap word. 1312 */ 1313 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD); 1314 1315 /* if not all bits of the dmap word are free, get the 1316 * starting bit number within the dmap word of the required 1317 * string of free bits and adjust the block number with the 1318 * value. 1319 */ 1320 if (leaf[word] < BUDMIN) 1321 blkno += 1322 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb); 1323 1324 /* allocate the blocks. 1325 */ 1326 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 1327 *results = blkno; 1328 1329 return (rc); 1330 } 1331 1332 return -ENOSPC; 1333} 1334 1335 1336/* 1337 * NAME: dbAllocAG() 1338 * 1339 * FUNCTION: attempt to allocate the specified number of contiguous 1340 * free blocks within the specified allocation group. 1341 * 1342 * unless the allocation group size is equal to the number 1343 * of blocks per dmap, the dmap control pages will be used to 1344 * find the required free space, if available. we start the 1345 * search at the highest dmap control page level which 1346 * distinctly describes the allocation group's free space 1347 * (i.e. the highest level at which the allocation group's 1348 * free space is not mixed in with that of any other group). 1349 * in addition, we start the search within this level at a 1350 * height of the dmapctl dmtree at which the nodes distinctly 1351 * describe the allocation group's free space. at this height, 1352 * the allocation group's free space may be represented by 1 1353 * or two sub-trees, depending on the allocation group size. 1354 * we search the top nodes of these subtrees left to right for 1355 * sufficient free space. if sufficient free space is found, 1356 * the subtree is searched to find the leftmost leaf that 1357 * has free space. once we have made it to the leaf, we 1358 * move the search to the next lower level dmap control page 1359 * corresponding to this leaf. we continue down the dmap control 1360 * pages until we find the dmap that contains or starts the 1361 * sufficient free space and we allocate at this dmap. 1362 * 1363 * if the allocation group size is equal to the dmap size, 1364 * we'll start at the dmap corresponding to the allocation 1365 * group and attempt the allocation at this level. 1366 * 1367 * the dmap control page search is also not performed if the 1368 * allocation group is completely free and we go to the first 1369 * dmap of the allocation group to do the allocation. this is 1370 * done because the allocation group may be part (not the first 1371 * part) of a larger binary buddy system, causing the dmap 1372 * control pages to indicate no free space (NOFREE) within 1373 * the allocation group. 1374 * 1375 * PARAMETERS: 1376 * bmp - pointer to bmap descriptor 1377 * agno - allocation group number. 1378 * nblocks - actual number of contiguous free blocks desired. 1379 * l2nb - log2 number of contiguous free blocks desired. 1380 * results - on successful return, set to the starting block number 1381 * of the newly allocated range. 1382 * 1383 * RETURN VALUES: 1384 * 0 - success 1385 * -ENOSPC - insufficient disk resources 1386 * -EIO - i/o error 1387 * 1388 * note: IWRITE_LOCK(ipmap) held on entry/exit; 1389 */ 1390static int 1391dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results) 1392{ 1393 struct metapage *mp; 1394 struct dmapctl *dcp; 1395 int rc, ti, i, k, m, n, agperlev; 1396 s64 blkno, lblkno; 1397 int budmin; 1398 1399 /* allocation request should not be for more than the 1400 * allocation group size. 1401 */ 1402 if (l2nb > bmp->db_agl2size) { 1403 jfs_error(bmp->db_ipbmap->i_sb, 1404 "allocation request is larger than the allocation group size\n"); 1405 return -EIO; 1406 } 1407 1408 /* determine the starting block number of the allocation 1409 * group. 1410 */ 1411 blkno = (s64) agno << bmp->db_agl2size; 1412 1413 /* check if the allocation group size is the minimum allocation 1414 * group size or if the allocation group is completely free. if 1415 * the allocation group size is the minimum size of BPERDMAP (i.e. 1416 * 1 dmap), there is no need to search the dmap control page (below) 1417 * that fully describes the allocation group since the allocation 1418 * group is already fully described by a dmap. in this case, we 1419 * just call dbAllocCtl() to search the dmap tree and allocate the 1420 * required space if available. 1421 * 1422 * if the allocation group is completely free, dbAllocCtl() is 1423 * also called to allocate the required space. this is done for 1424 * two reasons. first, it makes no sense searching the dmap control 1425 * pages for free space when we know that free space exists. second, 1426 * the dmap control pages may indicate that the allocation group 1427 * has no free space if the allocation group is part (not the first 1428 * part) of a larger binary buddy system. 1429 */ 1430 if (bmp->db_agsize == BPERDMAP 1431 || bmp->db_agfree[agno] == bmp->db_agsize) { 1432 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1433 if ((rc == -ENOSPC) && 1434 (bmp->db_agfree[agno] == bmp->db_agsize)) { 1435 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n", 1436 (unsigned long long) blkno, 1437 (unsigned long long) nblocks); 1438 jfs_error(bmp->db_ipbmap->i_sb, 1439 "dbAllocCtl failed in free AG\n"); 1440 } 1441 return (rc); 1442 } 1443 1444 /* the buffer for the dmap control page that fully describes the 1445 * allocation group. 1446 */ 1447 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel); 1448 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1449 if (mp == NULL) 1450 return -EIO; 1451 dcp = (struct dmapctl *) mp->data; 1452 budmin = dcp->budmin; 1453 1454 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1455 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 1456 release_metapage(mp); 1457 return -EIO; 1458 } 1459 1460 /* search the subtree(s) of the dmap control page that describes 1461 * the allocation group, looking for sufficient free space. to begin, 1462 * determine how many allocation groups are represented in a dmap 1463 * control page at the control page level (i.e. L0, L1, L2) that 1464 * fully describes an allocation group. next, determine the starting 1465 * tree index of this allocation group within the control page. 1466 */ 1467 agperlev = 1468 (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth; 1469 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1)); 1470 1471 /* dmap control page trees fan-out by 4 and a single allocation 1472 * group may be described by 1 or 2 subtrees within the ag level 1473 * dmap control page, depending upon the ag size. examine the ag's 1474 * subtrees for sufficient free space, starting with the leftmost 1475 * subtree. 1476 */ 1477 for (i = 0; i < bmp->db_agwidth; i++, ti++) { 1478 /* is there sufficient free space ? 1479 */ 1480 if (l2nb > dcp->stree[ti]) 1481 continue; 1482 1483 /* sufficient free space found in a subtree. now search down 1484 * the subtree to find the leftmost leaf that describes this 1485 * free space. 1486 */ 1487 for (k = bmp->db_agheight; k > 0; k--) { 1488 for (n = 0, m = (ti << 2) + 1; n < 4; n++) { 1489 if (l2nb <= dcp->stree[m + n]) { 1490 ti = m + n; 1491 break; 1492 } 1493 } 1494 if (n == 4) { 1495 jfs_error(bmp->db_ipbmap->i_sb, 1496 "failed descending stree\n"); 1497 release_metapage(mp); 1498 return -EIO; 1499 } 1500 } 1501 1502 /* determine the block number within the file system 1503 * that corresponds to this leaf. 1504 */ 1505 if (bmp->db_aglevel == 2) 1506 blkno = 0; 1507 else if (bmp->db_aglevel == 1) 1508 blkno &= ~(MAXL1SIZE - 1); 1509 else /* bmp->db_aglevel == 0 */ 1510 blkno &= ~(MAXL0SIZE - 1); 1511 1512 blkno += 1513 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin; 1514 1515 /* release the buffer in preparation for going down 1516 * the next level of dmap control pages. 1517 */ 1518 release_metapage(mp); 1519 1520 /* check if we need to continue to search down the lower 1521 * level dmap control pages. we need to if the number of 1522 * blocks required is less than maximum number of blocks 1523 * described at the next lower level. 1524 */ 1525 if (l2nb < budmin) { 1526 1527 /* search the lower level dmap control pages to get 1528 * the starting block number of the dmap that 1529 * contains or starts off the free space. 1530 */ 1531 if ((rc = 1532 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1, 1533 &blkno))) { 1534 if (rc == -ENOSPC) { 1535 jfs_error(bmp->db_ipbmap->i_sb, 1536 "control page inconsistent\n"); 1537 return -EIO; 1538 } 1539 return (rc); 1540 } 1541 } 1542 1543 /* allocate the blocks. 1544 */ 1545 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1546 if (rc == -ENOSPC) { 1547 jfs_error(bmp->db_ipbmap->i_sb, 1548 "unable to allocate blocks\n"); 1549 rc = -EIO; 1550 } 1551 return (rc); 1552 } 1553 1554 /* no space in the allocation group. release the buffer and 1555 * return -ENOSPC. 1556 */ 1557 release_metapage(mp); 1558 1559 return -ENOSPC; 1560} 1561 1562 1563/* 1564 * NAME: dbAllocAny() 1565 * 1566 * FUNCTION: attempt to allocate the specified number of contiguous 1567 * free blocks anywhere in the file system. 1568 * 1569 * dbAllocAny() attempts to find the sufficient free space by 1570 * searching down the dmap control pages, starting with the 1571 * highest level (i.e. L0, L1, L2) control page. if free space 1572 * large enough to satisfy the desired free space is found, the 1573 * desired free space is allocated. 1574 * 1575 * PARAMETERS: 1576 * bmp - pointer to bmap descriptor 1577 * nblocks - actual number of contiguous free blocks desired. 1578 * l2nb - log2 number of contiguous free blocks desired. 1579 * results - on successful return, set to the starting block number 1580 * of the newly allocated range. 1581 * 1582 * RETURN VALUES: 1583 * 0 - success 1584 * -ENOSPC - insufficient disk resources 1585 * -EIO - i/o error 1586 * 1587 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1588 */ 1589static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results) 1590{ 1591 int rc; 1592 s64 blkno = 0; 1593 1594 /* starting with the top level dmap control page, search 1595 * down the dmap control levels for sufficient free space. 1596 * if free space is found, dbFindCtl() returns the starting 1597 * block number of the dmap that contains or starts off the 1598 * range of free space. 1599 */ 1600 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno))) 1601 return (rc); 1602 1603 /* allocate the blocks. 1604 */ 1605 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1606 if (rc == -ENOSPC) { 1607 jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n"); 1608 return -EIO; 1609 } 1610 return (rc); 1611} 1612 1613 1614/* 1615 * NAME: dbDiscardAG() 1616 * 1617 * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG 1618 * 1619 * algorithm: 1620 * 1) allocate blocks, as large as possible and save them 1621 * while holding IWRITE_LOCK on ipbmap 1622 * 2) trim all these saved block/length values 1623 * 3) mark the blocks free again 1624 * 1625 * benefit: 1626 * - we work only on one ag at some time, minimizing how long we 1627 * need to lock ipbmap 1628 * - reading / writing the fs is possible most time, even on 1629 * trimming 1630 * 1631 * downside: 1632 * - we write two times to the dmapctl and dmap pages 1633 * - but for me, this seems the best way, better ideas? 1634 * /TR 2012 1635 * 1636 * PARAMETERS: 1637 * ip - pointer to in-core inode 1638 * agno - ag to trim 1639 * minlen - minimum value of contiguous blocks 1640 * 1641 * RETURN VALUES: 1642 * s64 - actual number of blocks trimmed 1643 */ 1644s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen) 1645{ 1646 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 1647 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 1648 s64 nblocks, blkno; 1649 u64 trimmed = 0; 1650 int rc, l2nb; 1651 struct super_block *sb = ipbmap->i_sb; 1652 1653 struct range2trim { 1654 u64 blkno; 1655 u64 nblocks; 1656 } *totrim, *tt; 1657 1658 /* max blkno / nblocks pairs to trim */ 1659 int count = 0, range_cnt; 1660 u64 max_ranges; 1661 1662 /* prevent others from writing new stuff here, while trimming */ 1663 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 1664 1665 nblocks = bmp->db_agfree[agno]; 1666 max_ranges = nblocks; 1667 do_div(max_ranges, minlen); 1668 range_cnt = min_t(u64, max_ranges + 1, 32 * 1024); 1669 totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS); 1670 if (totrim == NULL) { 1671 jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n"); 1672 IWRITE_UNLOCK(ipbmap); 1673 return 0; 1674 } 1675 1676 tt = totrim; 1677 while (nblocks >= minlen) { 1678 l2nb = BLKSTOL2(nblocks); 1679 1680 /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */ 1681 rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno); 1682 if (rc == 0) { 1683 tt->blkno = blkno; 1684 tt->nblocks = nblocks; 1685 tt++; count++; 1686 1687 /* the whole ag is free, trim now */ 1688 if (bmp->db_agfree[agno] == 0) 1689 break; 1690 1691 /* give a hint for the next while */ 1692 nblocks = bmp->db_agfree[agno]; 1693 continue; 1694 } else if (rc == -ENOSPC) { 1695 /* search for next smaller log2 block */ 1696 l2nb = BLKSTOL2(nblocks) - 1; 1697 nblocks = 1LL << l2nb; 1698 } else { 1699 /* Trim any already allocated blocks */ 1700 jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n"); 1701 break; 1702 } 1703 1704 /* check, if our trim array is full */ 1705 if (unlikely(count >= range_cnt - 1)) 1706 break; 1707 } 1708 IWRITE_UNLOCK(ipbmap); 1709 1710 tt->nblocks = 0; /* mark the current end */ 1711 for (tt = totrim; tt->nblocks != 0; tt++) { 1712 /* when mounted with online discard, dbFree() will 1713 * call jfs_issue_discard() itself */ 1714 if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) 1715 jfs_issue_discard(ip, tt->blkno, tt->nblocks); 1716 dbFree(ip, tt->blkno, tt->nblocks); 1717 trimmed += tt->nblocks; 1718 } 1719 kfree(totrim); 1720 1721 return trimmed; 1722} 1723 1724/* 1725 * NAME: dbFindCtl() 1726 * 1727 * FUNCTION: starting at a specified dmap control page level and block 1728 * number, search down the dmap control levels for a range of 1729 * contiguous free blocks large enough to satisfy an allocation 1730 * request for the specified number of free blocks. 1731 * 1732 * if sufficient contiguous free blocks are found, this routine 1733 * returns the starting block number within a dmap page that 1734 * contains or starts a range of contiqious free blocks that 1735 * is sufficient in size. 1736 * 1737 * PARAMETERS: 1738 * bmp - pointer to bmap descriptor 1739 * level - starting dmap control page level. 1740 * l2nb - log2 number of contiguous free blocks desired. 1741 * *blkno - on entry, starting block number for conducting the search. 1742 * on successful return, the first block within a dmap page 1743 * that contains or starts a range of contiguous free blocks. 1744 * 1745 * RETURN VALUES: 1746 * 0 - success 1747 * -ENOSPC - insufficient disk resources 1748 * -EIO - i/o error 1749 * 1750 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1751 */ 1752static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno) 1753{ 1754 int rc, leafidx, lev; 1755 s64 b, lblkno; 1756 struct dmapctl *dcp; 1757 int budmin; 1758 struct metapage *mp; 1759 1760 /* starting at the specified dmap control page level and block 1761 * number, search down the dmap control levels for the starting 1762 * block number of a dmap page that contains or starts off 1763 * sufficient free blocks. 1764 */ 1765 for (lev = level, b = *blkno; lev >= 0; lev--) { 1766 /* get the buffer of the dmap control page for the block 1767 * number and level (i.e. L0, L1, L2). 1768 */ 1769 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev); 1770 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1771 if (mp == NULL) 1772 return -EIO; 1773 dcp = (struct dmapctl *) mp->data; 1774 budmin = dcp->budmin; 1775 1776 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1777 jfs_error(bmp->db_ipbmap->i_sb, 1778 "Corrupt dmapctl page\n"); 1779 release_metapage(mp); 1780 return -EIO; 1781 } 1782 1783 /* search the tree within the dmap control page for 1784 * sufficient free space. if sufficient free space is found, 1785 * dbFindLeaf() returns the index of the leaf at which 1786 * free space was found. 1787 */ 1788 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx, true); 1789 1790 /* release the buffer. 1791 */ 1792 release_metapage(mp); 1793 1794 /* space found ? 1795 */ 1796 if (rc) { 1797 if (lev != level) { 1798 jfs_error(bmp->db_ipbmap->i_sb, 1799 "dmap inconsistent\n"); 1800 return -EIO; 1801 } 1802 return -ENOSPC; 1803 } 1804 1805 /* adjust the block number to reflect the location within 1806 * the dmap control page (i.e. the leaf) at which free 1807 * space was found. 1808 */ 1809 b += (((s64) leafidx) << budmin); 1810 1811 /* we stop the search at this dmap control page level if 1812 * the number of blocks required is greater than or equal 1813 * to the maximum number of blocks described at the next 1814 * (lower) level. 1815 */ 1816 if (l2nb >= budmin) 1817 break; 1818 } 1819 1820 *blkno = b; 1821 return (0); 1822} 1823 1824 1825/* 1826 * NAME: dbAllocCtl() 1827 * 1828 * FUNCTION: attempt to allocate a specified number of contiguous 1829 * blocks starting within a specific dmap. 1830 * 1831 * this routine is called by higher level routines that search 1832 * the dmap control pages above the actual dmaps for contiguous 1833 * free space. the result of successful searches by these 1834 * routines are the starting block numbers within dmaps, with 1835 * the dmaps themselves containing the desired contiguous free 1836 * space or starting a contiguous free space of desired size 1837 * that is made up of the blocks of one or more dmaps. these 1838 * calls should not fail due to insufficent resources. 1839 * 1840 * this routine is called in some cases where it is not known 1841 * whether it will fail due to insufficient resources. more 1842 * specifically, this occurs when allocating from an allocation 1843 * group whose size is equal to the number of blocks per dmap. 1844 * in this case, the dmap control pages are not examined prior 1845 * to calling this routine (to save pathlength) and the call 1846 * might fail. 1847 * 1848 * for a request size that fits within a dmap, this routine relies 1849 * upon the dmap's dmtree to find the requested contiguous free 1850 * space. for request sizes that are larger than a dmap, the 1851 * requested free space will start at the first block of the 1852 * first dmap (i.e. blkno). 1853 * 1854 * PARAMETERS: 1855 * bmp - pointer to bmap descriptor 1856 * nblocks - actual number of contiguous free blocks to allocate. 1857 * l2nb - log2 number of contiguous free blocks to allocate. 1858 * blkno - starting block number of the dmap to start the allocation 1859 * from. 1860 * results - on successful return, set to the starting block number 1861 * of the newly allocated range. 1862 * 1863 * RETURN VALUES: 1864 * 0 - success 1865 * -ENOSPC - insufficient disk resources 1866 * -EIO - i/o error 1867 * 1868 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1869 */ 1870static int 1871dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results) 1872{ 1873 int rc, nb; 1874 s64 b, lblkno, n; 1875 struct metapage *mp; 1876 struct dmap *dp; 1877 1878 /* check if the allocation request is confined to a single dmap. 1879 */ 1880 if (l2nb <= L2BPERDMAP) { 1881 /* get the buffer for the dmap. 1882 */ 1883 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 1884 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1885 if (mp == NULL) 1886 return -EIO; 1887 dp = (struct dmap *) mp->data; 1888 1889 /* try to allocate the blocks. 1890 */ 1891 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results); 1892 if (rc == 0) 1893 mark_metapage_dirty(mp); 1894 1895 release_metapage(mp); 1896 1897 return (rc); 1898 } 1899 1900 /* allocation request involving multiple dmaps. it must start on 1901 * a dmap boundary. 1902 */ 1903 assert((blkno & (BPERDMAP - 1)) == 0); 1904 1905 /* allocate the blocks dmap by dmap. 1906 */ 1907 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) { 1908 /* get the buffer for the dmap. 1909 */ 1910 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1911 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1912 if (mp == NULL) { 1913 rc = -EIO; 1914 goto backout; 1915 } 1916 dp = (struct dmap *) mp->data; 1917 1918 /* the dmap better be all free. 1919 */ 1920 if (dp->tree.stree[ROOT] != L2BPERDMAP) { 1921 release_metapage(mp); 1922 jfs_error(bmp->db_ipbmap->i_sb, 1923 "the dmap is not all free\n"); 1924 rc = -EIO; 1925 goto backout; 1926 } 1927 1928 /* determine how many blocks to allocate from this dmap. 1929 */ 1930 nb = min_t(s64, n, BPERDMAP); 1931 1932 /* allocate the blocks from the dmap. 1933 */ 1934 if ((rc = dbAllocDmap(bmp, dp, b, nb))) { 1935 release_metapage(mp); 1936 goto backout; 1937 } 1938 1939 /* write the buffer. 1940 */ 1941 write_metapage(mp); 1942 } 1943 1944 /* set the results (starting block number) and return. 1945 */ 1946 *results = blkno; 1947 return (0); 1948 1949 /* something failed in handling an allocation request involving 1950 * multiple dmaps. we'll try to clean up by backing out any 1951 * allocation that has already happened for this request. if 1952 * we fail in backing out the allocation, we'll mark the file 1953 * system to indicate that blocks have been leaked. 1954 */ 1955 backout: 1956 1957 /* try to backout the allocations dmap by dmap. 1958 */ 1959 for (n = nblocks - n, b = blkno; n > 0; 1960 n -= BPERDMAP, b += BPERDMAP) { 1961 /* get the buffer for this dmap. 1962 */ 1963 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1964 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1965 if (mp == NULL) { 1966 /* could not back out. mark the file system 1967 * to indicate that we have leaked blocks. 1968 */ 1969 jfs_error(bmp->db_ipbmap->i_sb, 1970 "I/O Error: Block Leakage\n"); 1971 continue; 1972 } 1973 dp = (struct dmap *) mp->data; 1974 1975 /* free the blocks is this dmap. 1976 */ 1977 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) { 1978 /* could not back out. mark the file system 1979 * to indicate that we have leaked blocks. 1980 */ 1981 release_metapage(mp); 1982 jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n"); 1983 continue; 1984 } 1985 1986 /* write the buffer. 1987 */ 1988 write_metapage(mp); 1989 } 1990 1991 return (rc); 1992} 1993 1994 1995/* 1996 * NAME: dbAllocDmapLev() 1997 * 1998 * FUNCTION: attempt to allocate a specified number of contiguous blocks 1999 * from a specified dmap. 2000 * 2001 * this routine checks if the contiguous blocks are available. 2002 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is 2003 * returned. 2004 * 2005 * PARAMETERS: 2006 * mp - pointer to bmap descriptor 2007 * dp - pointer to dmap to attempt to allocate blocks from. 2008 * l2nb - log2 number of contiguous block desired. 2009 * nblocks - actual number of contiguous block desired. 2010 * results - on successful return, set to the starting block number 2011 * of the newly allocated range. 2012 * 2013 * RETURN VALUES: 2014 * 0 - success 2015 * -ENOSPC - insufficient disk resources 2016 * -EIO - i/o error 2017 * 2018 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or 2019 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit; 2020 */ 2021static int 2022dbAllocDmapLev(struct bmap * bmp, 2023 struct dmap * dp, int nblocks, int l2nb, s64 * results) 2024{ 2025 s64 blkno; 2026 int leafidx, rc; 2027 2028 /* can't be more than a dmaps worth of blocks */ 2029 assert(l2nb <= L2BPERDMAP); 2030 2031 /* search the tree within the dmap page for sufficient 2032 * free space. if sufficient free space is found, dbFindLeaf() 2033 * returns the index of the leaf at which free space was found. 2034 */ 2035 if (dbFindLeaf((dmtree_t *) &dp->tree, l2nb, &leafidx, false)) 2036 return -ENOSPC; 2037 2038 if (leafidx < 0) 2039 return -EIO; 2040 2041 /* determine the block number within the file system corresponding 2042 * to the leaf at which free space was found. 2043 */ 2044 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD); 2045 2046 /* if not all bits of the dmap word are free, get the starting 2047 * bit number within the dmap word of the required string of free 2048 * bits and adjust the block number with this value. 2049 */ 2050 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN) 2051 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb); 2052 2053 /* allocate the blocks */ 2054 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 2055 *results = blkno; 2056 2057 return (rc); 2058} 2059 2060 2061/* 2062 * NAME: dbAllocDmap() 2063 * 2064 * FUNCTION: adjust the disk allocation map to reflect the allocation 2065 * of a specified block range within a dmap. 2066 * 2067 * this routine allocates the specified blocks from the dmap 2068 * through a call to dbAllocBits(). if the allocation of the 2069 * block range causes the maximum string of free blocks within 2070 * the dmap to change (i.e. the value of the root of the dmap's 2071 * dmtree), this routine will cause this change to be reflected 2072 * up through the appropriate levels of the dmap control pages 2073 * by a call to dbAdjCtl() for the L0 dmap control page that 2074 * covers this dmap. 2075 * 2076 * PARAMETERS: 2077 * bmp - pointer to bmap descriptor 2078 * dp - pointer to dmap to allocate the block range from. 2079 * blkno - starting block number of the block to be allocated. 2080 * nblocks - number of blocks to be allocated. 2081 * 2082 * RETURN VALUES: 2083 * 0 - success 2084 * -EIO - i/o error 2085 * 2086 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2087 */ 2088static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2089 int nblocks) 2090{ 2091 s8 oldroot; 2092 int rc; 2093 2094 /* save the current value of the root (i.e. maximum free string) 2095 * of the dmap tree. 2096 */ 2097 oldroot = dp->tree.stree[ROOT]; 2098 2099 /* allocate the specified (blocks) bits */ 2100 dbAllocBits(bmp, dp, blkno, nblocks); 2101 2102 /* if the root has not changed, done. */ 2103 if (dp->tree.stree[ROOT] == oldroot) 2104 return (0); 2105 2106 /* root changed. bubble the change up to the dmap control pages. 2107 * if the adjustment of the upper level control pages fails, 2108 * backout the bit allocation (thus making everything consistent). 2109 */ 2110 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0))) 2111 dbFreeBits(bmp, dp, blkno, nblocks); 2112 2113 return (rc); 2114} 2115 2116 2117/* 2118 * NAME: dbFreeDmap() 2119 * 2120 * FUNCTION: adjust the disk allocation map to reflect the allocation 2121 * of a specified block range within a dmap. 2122 * 2123 * this routine frees the specified blocks from the dmap through 2124 * a call to dbFreeBits(). if the deallocation of the block range 2125 * causes the maximum string of free blocks within the dmap to 2126 * change (i.e. the value of the root of the dmap's dmtree), this 2127 * routine will cause this change to be reflected up through the 2128 * appropriate levels of the dmap control pages by a call to 2129 * dbAdjCtl() for the L0 dmap control page that covers this dmap. 2130 * 2131 * PARAMETERS: 2132 * bmp - pointer to bmap descriptor 2133 * dp - pointer to dmap to free the block range from. 2134 * blkno - starting block number of the block to be freed. 2135 * nblocks - number of blocks to be freed. 2136 * 2137 * RETURN VALUES: 2138 * 0 - success 2139 * -EIO - i/o error 2140 * 2141 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2142 */ 2143static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2144 int nblocks) 2145{ 2146 s8 oldroot; 2147 int rc = 0, word; 2148 2149 /* save the current value of the root (i.e. maximum free string) 2150 * of the dmap tree. 2151 */ 2152 oldroot = dp->tree.stree[ROOT]; 2153 2154 /* free the specified (blocks) bits */ 2155 rc = dbFreeBits(bmp, dp, blkno, nblocks); 2156 2157 /* if error or the root has not changed, done. */ 2158 if (rc || (dp->tree.stree[ROOT] == oldroot)) 2159 return (rc); 2160 2161 /* root changed. bubble the change up to the dmap control pages. 2162 * if the adjustment of the upper level control pages fails, 2163 * backout the deallocation. 2164 */ 2165 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) { 2166 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 2167 2168 /* as part of backing out the deallocation, we will have 2169 * to back split the dmap tree if the deallocation caused 2170 * the freed blocks to become part of a larger binary buddy 2171 * system. 2172 */ 2173 if (dp->tree.stree[word] == NOFREE) 2174 dbBackSplit((dmtree_t *)&dp->tree, word, false); 2175 2176 dbAllocBits(bmp, dp, blkno, nblocks); 2177 } 2178 2179 return (rc); 2180} 2181 2182 2183/* 2184 * NAME: dbAllocBits() 2185 * 2186 * FUNCTION: allocate a specified block range from a dmap. 2187 * 2188 * this routine updates the dmap to reflect the working 2189 * state allocation of the specified block range. it directly 2190 * updates the bits of the working map and causes the adjustment 2191 * of the binary buddy system described by the dmap's dmtree 2192 * leaves to reflect the bits allocated. it also causes the 2193 * dmap's dmtree, as a whole, to reflect the allocated range. 2194 * 2195 * PARAMETERS: 2196 * bmp - pointer to bmap descriptor 2197 * dp - pointer to dmap to allocate bits from. 2198 * blkno - starting block number of the bits to be allocated. 2199 * nblocks - number of bits to be allocated. 2200 * 2201 * RETURN VALUES: none 2202 * 2203 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2204 */ 2205static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2206 int nblocks) 2207{ 2208 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2209 dmtree_t *tp = (dmtree_t *) & dp->tree; 2210 int size; 2211 s8 *leaf; 2212 2213 /* pick up a pointer to the leaves of the dmap tree */ 2214 leaf = dp->tree.stree + LEAFIND; 2215 2216 /* determine the bit number and word within the dmap of the 2217 * starting block. 2218 */ 2219 dbitno = blkno & (BPERDMAP - 1); 2220 word = dbitno >> L2DBWORD; 2221 2222 /* block range better be within the dmap */ 2223 assert(dbitno + nblocks <= BPERDMAP); 2224 2225 /* allocate the bits of the dmap's words corresponding to the block 2226 * range. not all bits of the first and last words may be contained 2227 * within the block range. if this is the case, we'll work against 2228 * those words (i.e. partial first and/or last) on an individual basis 2229 * (a single pass), allocating the bits of interest by hand and 2230 * updating the leaf corresponding to the dmap word. a single pass 2231 * will be used for all dmap words fully contained within the 2232 * specified range. within this pass, the bits of all fully contained 2233 * dmap words will be marked as free in a single shot and the leaves 2234 * will be updated. a single leaf may describe the free space of 2235 * multiple dmap words, so we may update only a subset of the actual 2236 * leaves corresponding to the dmap words of the block range. 2237 */ 2238 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2239 /* determine the bit number within the word and 2240 * the number of bits within the word. 2241 */ 2242 wbitno = dbitno & (DBWORD - 1); 2243 nb = min(rembits, DBWORD - wbitno); 2244 2245 /* check if only part of a word is to be allocated. 2246 */ 2247 if (nb < DBWORD) { 2248 /* allocate (set to 1) the appropriate bits within 2249 * this dmap word. 2250 */ 2251 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 2252 >> wbitno); 2253 2254 /* update the leaf for this dmap word. in addition 2255 * to setting the leaf value to the binary buddy max 2256 * of the updated dmap word, dbSplit() will split 2257 * the binary system of the leaves if need be. 2258 */ 2259 dbSplit(tp, word, BUDMIN, 2260 dbMaxBud((u8 *)&dp->wmap[word]), false); 2261 2262 word += 1; 2263 } else { 2264 /* one or more dmap words are fully contained 2265 * within the block range. determine how many 2266 * words and allocate (set to 1) the bits of these 2267 * words. 2268 */ 2269 nwords = rembits >> L2DBWORD; 2270 memset(&dp->wmap[word], (int) ONES, nwords * 4); 2271 2272 /* determine how many bits. 2273 */ 2274 nb = nwords << L2DBWORD; 2275 2276 /* now update the appropriate leaves to reflect 2277 * the allocated words. 2278 */ 2279 for (; nwords > 0; nwords -= nw) { 2280 if (leaf[word] < BUDMIN) { 2281 jfs_error(bmp->db_ipbmap->i_sb, 2282 "leaf page corrupt\n"); 2283 break; 2284 } 2285 2286 /* determine what the leaf value should be 2287 * updated to as the minimum of the l2 number 2288 * of bits being allocated and the l2 number 2289 * of bits currently described by this leaf. 2290 */ 2291 size = min_t(int, leaf[word], 2292 NLSTOL2BSZ(nwords)); 2293 2294 /* update the leaf to reflect the allocation. 2295 * in addition to setting the leaf value to 2296 * NOFREE, dbSplit() will split the binary 2297 * system of the leaves to reflect the current 2298 * allocation (size). 2299 */ 2300 dbSplit(tp, word, size, NOFREE, false); 2301 2302 /* get the number of dmap words handled */ 2303 nw = BUDSIZE(size, BUDMIN); 2304 word += nw; 2305 } 2306 } 2307 } 2308 2309 /* update the free count for this dmap */ 2310 le32_add_cpu(&dp->nfree, -nblocks); 2311 2312 BMAP_LOCK(bmp); 2313 2314 /* if this allocation group is completely free, 2315 * update the maximum allocation group number if this allocation 2316 * group is the new max. 2317 */ 2318 agno = blkno >> bmp->db_agl2size; 2319 if (agno > bmp->db_maxag) 2320 bmp->db_maxag = agno; 2321 2322 /* update the free count for the allocation group and map */ 2323 bmp->db_agfree[agno] -= nblocks; 2324 bmp->db_nfree -= nblocks; 2325 2326 BMAP_UNLOCK(bmp); 2327} 2328 2329 2330/* 2331 * NAME: dbFreeBits() 2332 * 2333 * FUNCTION: free a specified block range from a dmap. 2334 * 2335 * this routine updates the dmap to reflect the working 2336 * state allocation of the specified block range. it directly 2337 * updates the bits of the working map and causes the adjustment 2338 * of the binary buddy system described by the dmap's dmtree 2339 * leaves to reflect the bits freed. it also causes the dmap's 2340 * dmtree, as a whole, to reflect the deallocated range. 2341 * 2342 * PARAMETERS: 2343 * bmp - pointer to bmap descriptor 2344 * dp - pointer to dmap to free bits from. 2345 * blkno - starting block number of the bits to be freed. 2346 * nblocks - number of bits to be freed. 2347 * 2348 * RETURN VALUES: 0 for success 2349 * 2350 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2351 */ 2352static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2353 int nblocks) 2354{ 2355 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2356 dmtree_t *tp = (dmtree_t *) & dp->tree; 2357 int rc = 0; 2358 int size; 2359 2360 /* determine the bit number and word within the dmap of the 2361 * starting block. 2362 */ 2363 dbitno = blkno & (BPERDMAP - 1); 2364 word = dbitno >> L2DBWORD; 2365 2366 /* block range better be within the dmap. 2367 */ 2368 assert(dbitno + nblocks <= BPERDMAP); 2369 2370 /* free the bits of the dmaps words corresponding to the block range. 2371 * not all bits of the first and last words may be contained within 2372 * the block range. if this is the case, we'll work against those 2373 * words (i.e. partial first and/or last) on an individual basis 2374 * (a single pass), freeing the bits of interest by hand and updating 2375 * the leaf corresponding to the dmap word. a single pass will be used 2376 * for all dmap words fully contained within the specified range. 2377 * within this pass, the bits of all fully contained dmap words will 2378 * be marked as free in a single shot and the leaves will be updated. a 2379 * single leaf may describe the free space of multiple dmap words, 2380 * so we may update only a subset of the actual leaves corresponding 2381 * to the dmap words of the block range. 2382 * 2383 * dbJoin() is used to update leaf values and will join the binary 2384 * buddy system of the leaves if the new leaf values indicate this 2385 * should be done. 2386 */ 2387 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2388 /* determine the bit number within the word and 2389 * the number of bits within the word. 2390 */ 2391 wbitno = dbitno & (DBWORD - 1); 2392 nb = min(rembits, DBWORD - wbitno); 2393 2394 /* check if only part of a word is to be freed. 2395 */ 2396 if (nb < DBWORD) { 2397 /* free (zero) the appropriate bits within this 2398 * dmap word. 2399 */ 2400 dp->wmap[word] &= 2401 cpu_to_le32(~(ONES << (DBWORD - nb) 2402 >> wbitno)); 2403 2404 /* update the leaf for this dmap word. 2405 */ 2406 rc = dbJoin(tp, word, 2407 dbMaxBud((u8 *)&dp->wmap[word]), false); 2408 if (rc) 2409 return rc; 2410 2411 word += 1; 2412 } else { 2413 /* one or more dmap words are fully contained 2414 * within the block range. determine how many 2415 * words and free (zero) the bits of these words. 2416 */ 2417 nwords = rembits >> L2DBWORD; 2418 memset(&dp->wmap[word], 0, nwords * 4); 2419 2420 /* determine how many bits. 2421 */ 2422 nb = nwords << L2DBWORD; 2423 2424 /* now update the appropriate leaves to reflect 2425 * the freed words. 2426 */ 2427 for (; nwords > 0; nwords -= nw) { 2428 /* determine what the leaf value should be 2429 * updated to as the minimum of the l2 number 2430 * of bits being freed and the l2 (max) number 2431 * of bits that can be described by this leaf. 2432 */ 2433 size = 2434 min(LITOL2BSZ 2435 (word, L2LPERDMAP, BUDMIN), 2436 NLSTOL2BSZ(nwords)); 2437 2438 /* update the leaf. 2439 */ 2440 rc = dbJoin(tp, word, size, false); 2441 if (rc) 2442 return rc; 2443 2444 /* get the number of dmap words handled. 2445 */ 2446 nw = BUDSIZE(size, BUDMIN); 2447 word += nw; 2448 } 2449 } 2450 } 2451 2452 /* update the free count for this dmap. 2453 */ 2454 le32_add_cpu(&dp->nfree, nblocks); 2455 2456 BMAP_LOCK(bmp); 2457 2458 /* update the free count for the allocation group and 2459 * map. 2460 */ 2461 agno = blkno >> bmp->db_agl2size; 2462 bmp->db_nfree += nblocks; 2463 bmp->db_agfree[agno] += nblocks; 2464 2465 /* check if this allocation group is not completely free and 2466 * if it is currently the maximum (rightmost) allocation group. 2467 * if so, establish the new maximum allocation group number by 2468 * searching left for the first allocation group with allocation. 2469 */ 2470 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) || 2471 (agno == bmp->db_numag - 1 && 2472 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) { 2473 while (bmp->db_maxag > 0) { 2474 bmp->db_maxag -= 1; 2475 if (bmp->db_agfree[bmp->db_maxag] != 2476 bmp->db_agsize) 2477 break; 2478 } 2479 2480 /* re-establish the allocation group preference if the 2481 * current preference is right of the maximum allocation 2482 * group. 2483 */ 2484 if (bmp->db_agpref > bmp->db_maxag) 2485 bmp->db_agpref = bmp->db_maxag; 2486 } 2487 2488 BMAP_UNLOCK(bmp); 2489 2490 return 0; 2491} 2492 2493 2494/* 2495 * NAME: dbAdjCtl() 2496 * 2497 * FUNCTION: adjust a dmap control page at a specified level to reflect 2498 * the change in a lower level dmap or dmap control page's 2499 * maximum string of free blocks (i.e. a change in the root 2500 * of the lower level object's dmtree) due to the allocation 2501 * or deallocation of a range of blocks with a single dmap. 2502 * 2503 * on entry, this routine is provided with the new value of 2504 * the lower level dmap or dmap control page root and the 2505 * starting block number of the block range whose allocation 2506 * or deallocation resulted in the root change. this range 2507 * is respresented by a single leaf of the current dmapctl 2508 * and the leaf will be updated with this value, possibly 2509 * causing a binary buddy system within the leaves to be 2510 * split or joined. the update may also cause the dmapctl's 2511 * dmtree to be updated. 2512 * 2513 * if the adjustment of the dmap control page, itself, causes its 2514 * root to change, this change will be bubbled up to the next dmap 2515 * control level by a recursive call to this routine, specifying 2516 * the new root value and the next dmap control page level to 2517 * be adjusted. 2518 * PARAMETERS: 2519 * bmp - pointer to bmap descriptor 2520 * blkno - the first block of a block range within a dmap. it is 2521 * the allocation or deallocation of this block range that 2522 * requires the dmap control page to be adjusted. 2523 * newval - the new value of the lower level dmap or dmap control 2524 * page root. 2525 * alloc - 'true' if adjustment is due to an allocation. 2526 * level - current level of dmap control page (i.e. L0, L1, L2) to 2527 * be adjusted. 2528 * 2529 * RETURN VALUES: 2530 * 0 - success 2531 * -EIO - i/o error 2532 * 2533 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2534 */ 2535static int 2536dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level) 2537{ 2538 struct metapage *mp; 2539 s8 oldroot; 2540 int oldval; 2541 s64 lblkno; 2542 struct dmapctl *dcp; 2543 int rc, leafno, ti; 2544 2545 /* get the buffer for the dmap control page for the specified 2546 * block number and control page level. 2547 */ 2548 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level); 2549 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 2550 if (mp == NULL) 2551 return -EIO; 2552 dcp = (struct dmapctl *) mp->data; 2553 2554 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 2555 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 2556 release_metapage(mp); 2557 return -EIO; 2558 } 2559 2560 /* determine the leaf number corresponding to the block and 2561 * the index within the dmap control tree. 2562 */ 2563 leafno = BLKTOCTLLEAF(blkno, dcp->budmin); 2564 ti = leafno + le32_to_cpu(dcp->leafidx); 2565 2566 /* save the current leaf value and the current root level (i.e. 2567 * maximum l2 free string described by this dmapctl). 2568 */ 2569 oldval = dcp->stree[ti]; 2570 oldroot = dcp->stree[ROOT]; 2571 2572 /* check if this is a control page update for an allocation. 2573 * if so, update the leaf to reflect the new leaf value using 2574 * dbSplit(); otherwise (deallocation), use dbJoin() to update 2575 * the leaf with the new value. in addition to updating the 2576 * leaf, dbSplit() will also split the binary buddy system of 2577 * the leaves, if required, and bubble new values within the 2578 * dmapctl tree, if required. similarly, dbJoin() will join 2579 * the binary buddy system of leaves and bubble new values up 2580 * the dmapctl tree as required by the new leaf value. 2581 */ 2582 if (alloc) { 2583 /* check if we are in the middle of a binary buddy 2584 * system. this happens when we are performing the 2585 * first allocation out of an allocation group that 2586 * is part (not the first part) of a larger binary 2587 * buddy system. if we are in the middle, back split 2588 * the system prior to calling dbSplit() which assumes 2589 * that it is at the front of a binary buddy system. 2590 */ 2591 if (oldval == NOFREE) { 2592 rc = dbBackSplit((dmtree_t *)dcp, leafno, true); 2593 if (rc) 2594 return rc; 2595 oldval = dcp->stree[ti]; 2596 } 2597 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval, true); 2598 } else { 2599 rc = dbJoin((dmtree_t *) dcp, leafno, newval, true); 2600 if (rc) 2601 return rc; 2602 } 2603 2604 /* check if the root of the current dmap control page changed due 2605 * to the update and if the current dmap control page is not at 2606 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e. 2607 * root changed and this is not the top level), call this routine 2608 * again (recursion) for the next higher level of the mapping to 2609 * reflect the change in root for the current dmap control page. 2610 */ 2611 if (dcp->stree[ROOT] != oldroot) { 2612 /* are we below the top level of the map. if so, 2613 * bubble the root up to the next higher level. 2614 */ 2615 if (level < bmp->db_maxlevel) { 2616 /* bubble up the new root of this dmap control page to 2617 * the next level. 2618 */ 2619 if ((rc = 2620 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc, 2621 level + 1))) { 2622 /* something went wrong in bubbling up the new 2623 * root value, so backout the changes to the 2624 * current dmap control page. 2625 */ 2626 if (alloc) { 2627 dbJoin((dmtree_t *) dcp, leafno, 2628 oldval, true); 2629 } else { 2630 /* the dbJoin() above might have 2631 * caused a larger binary buddy system 2632 * to form and we may now be in the 2633 * middle of it. if this is the case, 2634 * back split the buddies. 2635 */ 2636 if (dcp->stree[ti] == NOFREE) 2637 dbBackSplit((dmtree_t *) 2638 dcp, leafno, true); 2639 dbSplit((dmtree_t *) dcp, leafno, 2640 dcp->budmin, oldval, true); 2641 } 2642 2643 /* release the buffer and return the error. 2644 */ 2645 release_metapage(mp); 2646 return (rc); 2647 } 2648 } else { 2649 /* we're at the top level of the map. update 2650 * the bmap control page to reflect the size 2651 * of the maximum free buddy system. 2652 */ 2653 assert(level == bmp->db_maxlevel); 2654 if (bmp->db_maxfreebud != oldroot) { 2655 jfs_error(bmp->db_ipbmap->i_sb, 2656 "the maximum free buddy is not the old root\n"); 2657 } 2658 bmp->db_maxfreebud = dcp->stree[ROOT]; 2659 } 2660 } 2661 2662 /* write the buffer. 2663 */ 2664 write_metapage(mp); 2665 2666 return (0); 2667} 2668 2669 2670/* 2671 * NAME: dbSplit() 2672 * 2673 * FUNCTION: update the leaf of a dmtree with a new value, splitting 2674 * the leaf from the binary buddy system of the dmtree's 2675 * leaves, as required. 2676 * 2677 * PARAMETERS: 2678 * tp - pointer to the tree containing the leaf. 2679 * leafno - the number of the leaf to be updated. 2680 * splitsz - the size the binary buddy system starting at the leaf 2681 * must be split to, specified as the log2 number of blocks. 2682 * newval - the new value for the leaf. 2683 * 2684 * RETURN VALUES: none 2685 * 2686 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2687 */ 2688static void dbSplit(dmtree_t *tp, int leafno, int splitsz, int newval, bool is_ctl) 2689{ 2690 int budsz; 2691 int cursz; 2692 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2693 2694 /* check if the leaf needs to be split. 2695 */ 2696 if (leaf[leafno] > tp->dmt_budmin) { 2697 /* the split occurs by cutting the buddy system in half 2698 * at the specified leaf until we reach the specified 2699 * size. pick up the starting split size (current size 2700 * - 1 in l2) and the corresponding buddy size. 2701 */ 2702 cursz = leaf[leafno] - 1; 2703 budsz = BUDSIZE(cursz, tp->dmt_budmin); 2704 2705 /* split until we reach the specified size. 2706 */ 2707 while (cursz >= splitsz) { 2708 /* update the buddy's leaf with its new value. 2709 */ 2710 dbAdjTree(tp, leafno ^ budsz, cursz, is_ctl); 2711 2712 /* on to the next size and buddy. 2713 */ 2714 cursz -= 1; 2715 budsz >>= 1; 2716 } 2717 } 2718 2719 /* adjust the dmap tree to reflect the specified leaf's new 2720 * value. 2721 */ 2722 dbAdjTree(tp, leafno, newval, is_ctl); 2723} 2724 2725 2726/* 2727 * NAME: dbBackSplit() 2728 * 2729 * FUNCTION: back split the binary buddy system of dmtree leaves 2730 * that hold a specified leaf until the specified leaf 2731 * starts its own binary buddy system. 2732 * 2733 * the allocators typically perform allocations at the start 2734 * of binary buddy systems and dbSplit() is used to accomplish 2735 * any required splits. in some cases, however, allocation 2736 * may occur in the middle of a binary system and requires a 2737 * back split, with the split proceeding out from the middle of 2738 * the system (less efficient) rather than the start of the 2739 * system (more efficient). the cases in which a back split 2740 * is required are rare and are limited to the first allocation 2741 * within an allocation group which is a part (not first part) 2742 * of a larger binary buddy system and a few exception cases 2743 * in which a previous join operation must be backed out. 2744 * 2745 * PARAMETERS: 2746 * tp - pointer to the tree containing the leaf. 2747 * leafno - the number of the leaf to be updated. 2748 * 2749 * RETURN VALUES: none 2750 * 2751 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2752 */ 2753static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl) 2754{ 2755 int budsz, bud, w, bsz, size; 2756 int cursz; 2757 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2758 2759 /* leaf should be part (not first part) of a binary 2760 * buddy system. 2761 */ 2762 assert(leaf[leafno] == NOFREE); 2763 2764 /* the back split is accomplished by iteratively finding the leaf 2765 * that starts the buddy system that contains the specified leaf and 2766 * splitting that system in two. this iteration continues until 2767 * the specified leaf becomes the start of a buddy system. 2768 * 2769 * determine maximum possible l2 size for the specified leaf. 2770 */ 2771 size = 2772 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs), 2773 tp->dmt_budmin); 2774 2775 /* determine the number of leaves covered by this size. this 2776 * is the buddy size that we will start with as we search for 2777 * the buddy system that contains the specified leaf. 2778 */ 2779 budsz = BUDSIZE(size, tp->dmt_budmin); 2780 2781 /* back split. 2782 */ 2783 while (leaf[leafno] == NOFREE) { 2784 /* find the leftmost buddy leaf. 2785 */ 2786 for (w = leafno, bsz = budsz;; bsz <<= 1, 2787 w = (w < bud) ? w : bud) { 2788 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) { 2789 jfs_err("JFS: block map error in dbBackSplit"); 2790 return -EIO; 2791 } 2792 2793 /* determine the buddy. 2794 */ 2795 bud = w ^ bsz; 2796 2797 /* check if this buddy is the start of the system. 2798 */ 2799 if (leaf[bud] != NOFREE) { 2800 /* split the leaf at the start of the 2801 * system in two. 2802 */ 2803 cursz = leaf[bud] - 1; 2804 dbSplit(tp, bud, cursz, cursz, is_ctl); 2805 break; 2806 } 2807 } 2808 } 2809 2810 if (leaf[leafno] != size) { 2811 jfs_err("JFS: wrong leaf value in dbBackSplit"); 2812 return -EIO; 2813 } 2814 return 0; 2815} 2816 2817 2818/* 2819 * NAME: dbJoin() 2820 * 2821 * FUNCTION: update the leaf of a dmtree with a new value, joining 2822 * the leaf with other leaves of the dmtree into a multi-leaf 2823 * binary buddy system, as required. 2824 * 2825 * PARAMETERS: 2826 * tp - pointer to the tree containing the leaf. 2827 * leafno - the number of the leaf to be updated. 2828 * newval - the new value for the leaf. 2829 * 2830 * RETURN VALUES: none 2831 */ 2832static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl) 2833{ 2834 int budsz, buddy; 2835 s8 *leaf; 2836 2837 /* can the new leaf value require a join with other leaves ? 2838 */ 2839 if (newval >= tp->dmt_budmin) { 2840 /* pickup a pointer to the leaves of the tree. 2841 */ 2842 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2843 2844 /* try to join the specified leaf into a large binary 2845 * buddy system. the join proceeds by attempting to join 2846 * the specified leafno with its buddy (leaf) at new value. 2847 * if the join occurs, we attempt to join the left leaf 2848 * of the joined buddies with its buddy at new value + 1. 2849 * we continue to join until we find a buddy that cannot be 2850 * joined (does not have a value equal to the size of the 2851 * last join) or until all leaves have been joined into a 2852 * single system. 2853 * 2854 * get the buddy size (number of words covered) of 2855 * the new value. 2856 */ 2857 budsz = BUDSIZE(newval, tp->dmt_budmin); 2858 2859 /* try to join. 2860 */ 2861 while (budsz < le32_to_cpu(tp->dmt_nleafs)) { 2862 /* get the buddy leaf. 2863 */ 2864 buddy = leafno ^ budsz; 2865 2866 /* if the leaf's new value is greater than its 2867 * buddy's value, we join no more. 2868 */ 2869 if (newval > leaf[buddy]) 2870 break; 2871 2872 /* It shouldn't be less */ 2873 if (newval < leaf[buddy]) 2874 return -EIO; 2875 2876 /* check which (leafno or buddy) is the left buddy. 2877 * the left buddy gets to claim the blocks resulting 2878 * from the join while the right gets to claim none. 2879 * the left buddy is also eligible to participate in 2880 * a join at the next higher level while the right 2881 * is not. 2882 * 2883 */ 2884 if (leafno < buddy) { 2885 /* leafno is the left buddy. 2886 */ 2887 dbAdjTree(tp, buddy, NOFREE, is_ctl); 2888 } else { 2889 /* buddy is the left buddy and becomes 2890 * leafno. 2891 */ 2892 dbAdjTree(tp, leafno, NOFREE, is_ctl); 2893 leafno = buddy; 2894 } 2895 2896 /* on to try the next join. 2897 */ 2898 newval += 1; 2899 budsz <<= 1; 2900 } 2901 } 2902 2903 /* update the leaf value. 2904 */ 2905 dbAdjTree(tp, leafno, newval, is_ctl); 2906 2907 return 0; 2908} 2909 2910 2911/* 2912 * NAME: dbAdjTree() 2913 * 2914 * FUNCTION: update a leaf of a dmtree with a new value, adjusting 2915 * the dmtree, as required, to reflect the new leaf value. 2916 * the combination of any buddies must already be done before 2917 * this is called. 2918 * 2919 * PARAMETERS: 2920 * tp - pointer to the tree to be adjusted. 2921 * leafno - the number of the leaf to be updated. 2922 * newval - the new value for the leaf. 2923 * 2924 * RETURN VALUES: none 2925 */ 2926static void dbAdjTree(dmtree_t *tp, int leafno, int newval, bool is_ctl) 2927{ 2928 int lp, pp, k; 2929 int max, size; 2930 2931 size = is_ctl ? CTLTREESIZE : TREESIZE; 2932 2933 /* pick up the index of the leaf for this leafno. 2934 */ 2935 lp = leafno + le32_to_cpu(tp->dmt_leafidx); 2936 2937 if (WARN_ON_ONCE(lp >= size || lp < 0)) 2938 return; 2939 2940 /* is the current value the same as the old value ? if so, 2941 * there is nothing to do. 2942 */ 2943 if (tp->dmt_stree[lp] == newval) 2944 return; 2945 2946 /* set the new value. 2947 */ 2948 tp->dmt_stree[lp] = newval; 2949 2950 /* bubble the new value up the tree as required. 2951 */ 2952 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) { 2953 /* get the index of the first leaf of the 4 leaf 2954 * group containing the specified leaf (leafno). 2955 */ 2956 lp = ((lp - 1) & ~0x03) + 1; 2957 2958 /* get the index of the parent of this 4 leaf group. 2959 */ 2960 pp = (lp - 1) >> 2; 2961 2962 /* determine the maximum of the 4 leaves. 2963 */ 2964 max = TREEMAX(&tp->dmt_stree[lp]); 2965 2966 /* if the maximum of the 4 is the same as the 2967 * parent's value, we're done. 2968 */ 2969 if (tp->dmt_stree[pp] == max) 2970 break; 2971 2972 /* parent gets new value. 2973 */ 2974 tp->dmt_stree[pp] = max; 2975 2976 /* parent becomes leaf for next go-round. 2977 */ 2978 lp = pp; 2979 } 2980} 2981 2982 2983/* 2984 * NAME: dbFindLeaf() 2985 * 2986 * FUNCTION: search a dmtree_t for sufficient free blocks, returning 2987 * the index of a leaf describing the free blocks if 2988 * sufficient free blocks are found. 2989 * 2990 * the search starts at the top of the dmtree_t tree and 2991 * proceeds down the tree to the leftmost leaf with sufficient 2992 * free space. 2993 * 2994 * PARAMETERS: 2995 * tp - pointer to the tree to be searched. 2996 * l2nb - log2 number of free blocks to search for. 2997 * leafidx - return pointer to be set to the index of the leaf 2998 * describing at least l2nb free blocks if sufficient 2999 * free blocks are found. 3000 * is_ctl - determines if the tree is of type ctl 3001 * 3002 * RETURN VALUES: 3003 * 0 - success 3004 * -ENOSPC - insufficient free blocks. 3005 */ 3006static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl) 3007{ 3008 int ti, n = 0, k, x = 0; 3009 int max_size; 3010 3011 max_size = is_ctl ? CTLTREESIZE : TREESIZE; 3012 3013 /* first check the root of the tree to see if there is 3014 * sufficient free space. 3015 */ 3016 if (l2nb > tp->dmt_stree[ROOT]) 3017 return -ENOSPC; 3018 3019 /* sufficient free space available. now search down the tree 3020 * starting at the next level for the leftmost leaf that 3021 * describes sufficient free space. 3022 */ 3023 for (k = le32_to_cpu(tp->dmt_height), ti = 1; 3024 k > 0; k--, ti = ((ti + n) << 2) + 1) { 3025 /* search the four nodes at this level, starting from 3026 * the left. 3027 */ 3028 for (x = ti, n = 0; n < 4; n++) { 3029 /* sufficient free space found. move to the next 3030 * level (or quit if this is the last level). 3031 */ 3032 if (x + n > max_size) 3033 return -ENOSPC; 3034 if (l2nb <= tp->dmt_stree[x + n]) 3035 break; 3036 } 3037 3038 /* better have found something since the higher 3039 * levels of the tree said it was here. 3040 */ 3041 assert(n < 4); 3042 } 3043 3044 /* set the return to the leftmost leaf describing sufficient 3045 * free space. 3046 */ 3047 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx); 3048 3049 return (0); 3050} 3051 3052 3053/* 3054 * NAME: dbFindBits() 3055 * 3056 * FUNCTION: find a specified number of binary buddy free bits within a 3057 * dmap bitmap word value. 3058 * 3059 * this routine searches the bitmap value for (1 << l2nb) free 3060 * bits at (1 << l2nb) alignments within the value. 3061 * 3062 * PARAMETERS: 3063 * word - dmap bitmap word value. 3064 * l2nb - number of free bits specified as a log2 number. 3065 * 3066 * RETURN VALUES: 3067 * starting bit number of free bits. 3068 */ 3069static int dbFindBits(u32 word, int l2nb) 3070{ 3071 int bitno, nb; 3072 u32 mask; 3073 3074 /* get the number of bits. 3075 */ 3076 nb = 1 << l2nb; 3077 assert(nb <= DBWORD); 3078 3079 /* complement the word so we can use a mask (i.e. 0s represent 3080 * free bits) and compute the mask. 3081 */ 3082 word = ~word; 3083 mask = ONES << (DBWORD - nb); 3084 3085 /* scan the word for nb free bits at nb alignments. 3086 */ 3087 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) { 3088 if ((mask & word) == mask) 3089 break; 3090 } 3091 3092 ASSERT(bitno < 32); 3093 3094 /* return the bit number. 3095 */ 3096 return (bitno); 3097} 3098 3099 3100/* 3101 * NAME: dbMaxBud(u8 *cp) 3102 * 3103 * FUNCTION: determine the largest binary buddy string of free 3104 * bits within 32-bits of the map. 3105 * 3106 * PARAMETERS: 3107 * cp - pointer to the 32-bit value. 3108 * 3109 * RETURN VALUES: 3110 * largest binary buddy of free bits within a dmap word. 3111 */ 3112static int dbMaxBud(u8 * cp) 3113{ 3114 signed char tmp1, tmp2; 3115 3116 /* check if the wmap word is all free. if so, the 3117 * free buddy size is BUDMIN. 3118 */ 3119 if (*((uint *) cp) == 0) 3120 return (BUDMIN); 3121 3122 /* check if the wmap word is half free. if so, the 3123 * free buddy size is BUDMIN-1. 3124 */ 3125 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0) 3126 return (BUDMIN - 1); 3127 3128 /* not all free or half free. determine the free buddy 3129 * size thru table lookup using quarters of the wmap word. 3130 */ 3131 tmp1 = max(budtab[cp[2]], budtab[cp[3]]); 3132 tmp2 = max(budtab[cp[0]], budtab[cp[1]]); 3133 return (max(tmp1, tmp2)); 3134} 3135 3136 3137/* 3138 * NAME: cnttz(uint word) 3139 * 3140 * FUNCTION: determine the number of trailing zeros within a 32-bit 3141 * value. 3142 * 3143 * PARAMETERS: 3144 * value - 32-bit value to be examined. 3145 * 3146 * RETURN VALUES: 3147 * count of trailing zeros 3148 */ 3149static int cnttz(u32 word) 3150{ 3151 int n; 3152 3153 for (n = 0; n < 32; n++, word >>= 1) { 3154 if (word & 0x01) 3155 break; 3156 } 3157 3158 return (n); 3159} 3160 3161 3162/* 3163 * NAME: cntlz(u32 value) 3164 * 3165 * FUNCTION: determine the number of leading zeros within a 32-bit 3166 * value. 3167 * 3168 * PARAMETERS: 3169 * value - 32-bit value to be examined. 3170 * 3171 * RETURN VALUES: 3172 * count of leading zeros 3173 */ 3174static int cntlz(u32 value) 3175{ 3176 int n; 3177 3178 for (n = 0; n < 32; n++, value <<= 1) { 3179 if (value & HIGHORDER) 3180 break; 3181 } 3182 return (n); 3183} 3184 3185 3186/* 3187 * NAME: blkstol2(s64 nb) 3188 * 3189 * FUNCTION: convert a block count to its log2 value. if the block 3190 * count is not a l2 multiple, it is rounded up to the next 3191 * larger l2 multiple. 3192 * 3193 * PARAMETERS: 3194 * nb - number of blocks 3195 * 3196 * RETURN VALUES: 3197 * log2 number of blocks 3198 */ 3199static int blkstol2(s64 nb) 3200{ 3201 int l2nb; 3202 s64 mask; /* meant to be signed */ 3203 3204 mask = (s64) 1 << (64 - 1); 3205 3206 /* count the leading bits. 3207 */ 3208 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) { 3209 /* leading bit found. 3210 */ 3211 if (nb & mask) { 3212 /* determine the l2 value. 3213 */ 3214 l2nb = (64 - 1) - l2nb; 3215 3216 /* check if we need to round up. 3217 */ 3218 if (~mask & nb) 3219 l2nb++; 3220 3221 return (l2nb); 3222 } 3223 } 3224 assert(0); 3225 return 0; /* fix compiler warning */ 3226} 3227 3228 3229/* 3230 * NAME: dbAllocBottomUp() 3231 * 3232 * FUNCTION: alloc the specified block range from the working block 3233 * allocation map. 3234 * 3235 * the blocks will be alloc from the working map one dmap 3236 * at a time. 3237 * 3238 * PARAMETERS: 3239 * ip - pointer to in-core inode; 3240 * blkno - starting block number to be freed. 3241 * nblocks - number of blocks to be freed. 3242 * 3243 * RETURN VALUES: 3244 * 0 - success 3245 * -EIO - i/o error 3246 */ 3247int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks) 3248{ 3249 struct metapage *mp; 3250 struct dmap *dp; 3251 int nb, rc; 3252 s64 lblkno, rem; 3253 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 3254 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 3255 3256 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 3257 3258 /* block to be allocated better be within the mapsize. */ 3259 ASSERT(nblocks <= bmp->db_mapsize - blkno); 3260 3261 /* 3262 * allocate the blocks a dmap at a time. 3263 */ 3264 mp = NULL; 3265 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 3266 /* release previous dmap if any */ 3267 if (mp) { 3268 write_metapage(mp); 3269 } 3270 3271 /* get the buffer for the current dmap. */ 3272 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 3273 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 3274 if (mp == NULL) { 3275 IREAD_UNLOCK(ipbmap); 3276 return -EIO; 3277 } 3278 dp = (struct dmap *) mp->data; 3279 3280 /* determine the number of blocks to be allocated from 3281 * this dmap. 3282 */ 3283 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 3284 3285 /* allocate the blocks. */ 3286 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) { 3287 release_metapage(mp); 3288 IREAD_UNLOCK(ipbmap); 3289 return (rc); 3290 } 3291 } 3292 3293 /* write the last buffer. */ 3294 write_metapage(mp); 3295 3296 IREAD_UNLOCK(ipbmap); 3297 3298 return (0); 3299} 3300 3301 3302static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 3303 int nblocks) 3304{ 3305 int rc; 3306 int dbitno, word, rembits, nb, nwords, wbitno, agno; 3307 s8 oldroot; 3308 struct dmaptree *tp = (struct dmaptree *) & dp->tree; 3309 3310 /* save the current value of the root (i.e. maximum free string) 3311 * of the dmap tree. 3312 */ 3313 oldroot = tp->stree[ROOT]; 3314 3315 /* determine the bit number and word within the dmap of the 3316 * starting block. 3317 */ 3318 dbitno = blkno & (BPERDMAP - 1); 3319 word = dbitno >> L2DBWORD; 3320 3321 /* block range better be within the dmap */ 3322 assert(dbitno + nblocks <= BPERDMAP); 3323 3324 /* allocate the bits of the dmap's words corresponding to the block 3325 * range. not all bits of the first and last words may be contained 3326 * within the block range. if this is the case, we'll work against 3327 * those words (i.e. partial first and/or last) on an individual basis 3328 * (a single pass), allocating the bits of interest by hand and 3329 * updating the leaf corresponding to the dmap word. a single pass 3330 * will be used for all dmap words fully contained within the 3331 * specified range. within this pass, the bits of all fully contained 3332 * dmap words will be marked as free in a single shot and the leaves 3333 * will be updated. a single leaf may describe the free space of 3334 * multiple dmap words, so we may update only a subset of the actual 3335 * leaves corresponding to the dmap words of the block range. 3336 */ 3337 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 3338 /* determine the bit number within the word and 3339 * the number of bits within the word. 3340 */ 3341 wbitno = dbitno & (DBWORD - 1); 3342 nb = min(rembits, DBWORD - wbitno); 3343 3344 /* check if only part of a word is to be allocated. 3345 */ 3346 if (nb < DBWORD) { 3347 /* allocate (set to 1) the appropriate bits within 3348 * this dmap word. 3349 */ 3350 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 3351 >> wbitno); 3352 3353 word++; 3354 } else { 3355 /* one or more dmap words are fully contained 3356 * within the block range. determine how many 3357 * words and allocate (set to 1) the bits of these 3358 * words. 3359 */ 3360 nwords = rembits >> L2DBWORD; 3361 memset(&dp->wmap[word], (int) ONES, nwords * 4); 3362 3363 /* determine how many bits */ 3364 nb = nwords << L2DBWORD; 3365 word += nwords; 3366 } 3367 } 3368 3369 /* update the free count for this dmap */ 3370 le32_add_cpu(&dp->nfree, -nblocks); 3371 3372 /* reconstruct summary tree */ 3373 dbInitDmapTree(dp); 3374 3375 BMAP_LOCK(bmp); 3376 3377 /* if this allocation group is completely free, 3378 * update the highest active allocation group number 3379 * if this allocation group is the new max. 3380 */ 3381 agno = blkno >> bmp->db_agl2size; 3382 if (agno > bmp->db_maxag) 3383 bmp->db_maxag = agno; 3384 3385 /* update the free count for the allocation group and map */ 3386 bmp->db_agfree[agno] -= nblocks; 3387 bmp->db_nfree -= nblocks; 3388 3389 BMAP_UNLOCK(bmp); 3390 3391 /* if the root has not changed, done. */ 3392 if (tp->stree[ROOT] == oldroot) 3393 return (0); 3394 3395 /* root changed. bubble the change up to the dmap control pages. 3396 * if the adjustment of the upper level control pages fails, 3397 * backout the bit allocation (thus making everything consistent). 3398 */ 3399 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0))) 3400 dbFreeBits(bmp, dp, blkno, nblocks); 3401 3402 return (rc); 3403} 3404 3405 3406/* 3407 * NAME: dbExtendFS() 3408 * 3409 * FUNCTION: extend bmap from blkno for nblocks; 3410 * dbExtendFS() updates bmap ready for dbAllocBottomUp(); 3411 * 3412 * L2 3413 * | 3414 * L1---------------------------------L1 3415 * | | 3416 * L0---------L0---------L0 L0---------L0---------L0 3417 * | | | | | | 3418 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm; 3419 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm 3420 * 3421 * <---old---><----------------------------extend-----------------------> 3422 */ 3423int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks) 3424{ 3425 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb); 3426 int nbperpage = sbi->nbperpage; 3427 int i, i0 = true, j, j0 = true, k, n; 3428 s64 newsize; 3429 s64 p; 3430 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL; 3431 struct dmapctl *l2dcp, *l1dcp, *l0dcp; 3432 struct dmap *dp; 3433 s8 *l0leaf, *l1leaf, *l2leaf; 3434 struct bmap *bmp = sbi->bmap; 3435 int agno, l2agsize, oldl2agsize; 3436 s64 ag_rem; 3437 3438 newsize = blkno + nblocks; 3439 3440 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld", 3441 (long long) blkno, (long long) nblocks, (long long) newsize); 3442 3443 /* 3444 * initialize bmap control page. 3445 * 3446 * all the data in bmap control page should exclude 3447 * the mkfs hidden dmap page. 3448 */ 3449 3450 /* update mapsize */ 3451 bmp->db_mapsize = newsize; 3452 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize); 3453 3454 /* compute new AG size */ 3455 l2agsize = dbGetL2AGSize(newsize); 3456 oldl2agsize = bmp->db_agl2size; 3457 3458 bmp->db_agl2size = l2agsize; 3459 bmp->db_agsize = 1 << l2agsize; 3460 3461 /* compute new number of AG */ 3462 agno = bmp->db_numag; 3463 bmp->db_numag = newsize >> l2agsize; 3464 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0; 3465 3466 /* 3467 * reconfigure db_agfree[] 3468 * from old AG configuration to new AG configuration; 3469 * 3470 * coalesce contiguous k (newAGSize/oldAGSize) AGs; 3471 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn; 3472 * note: new AG size = old AG size * (2**x). 3473 */ 3474 if (l2agsize == oldl2agsize) 3475 goto extend; 3476 k = 1 << (l2agsize - oldl2agsize); 3477 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */ 3478 for (i = 0, n = 0; i < agno; n++) { 3479 bmp->db_agfree[n] = 0; /* init collection point */ 3480 3481 /* coalesce contiguous k AGs; */ 3482 for (j = 0; j < k && i < agno; j++, i++) { 3483 /* merge AGi to AGn */ 3484 bmp->db_agfree[n] += bmp->db_agfree[i]; 3485 } 3486 } 3487 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */ 3488 3489 for (; n < MAXAG; n++) 3490 bmp->db_agfree[n] = 0; 3491 3492 /* 3493 * update highest active ag number 3494 */ 3495 3496 bmp->db_maxag = bmp->db_maxag / k; 3497 3498 /* 3499 * extend bmap 3500 * 3501 * update bit maps and corresponding level control pages; 3502 * global control page db_nfree, db_agfree[agno], db_maxfreebud; 3503 */ 3504 extend: 3505 /* get L2 page */ 3506 p = BMAPBLKNO + nbperpage; /* L2 page */ 3507 l2mp = read_metapage(ipbmap, p, PSIZE, 0); 3508 if (!l2mp) { 3509 jfs_error(ipbmap->i_sb, "L2 page could not be read\n"); 3510 return -EIO; 3511 } 3512 l2dcp = (struct dmapctl *) l2mp->data; 3513 3514 /* compute start L1 */ 3515 k = blkno >> L2MAXL1SIZE; 3516 l2leaf = l2dcp->stree + CTLLEAFIND + k; 3517 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */ 3518 3519 /* 3520 * extend each L1 in L2 3521 */ 3522 for (; k < LPERCTL; k++, p += nbperpage) { 3523 /* get L1 page */ 3524 if (j0) { 3525 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */ 3526 l1mp = read_metapage(ipbmap, p, PSIZE, 0); 3527 if (l1mp == NULL) 3528 goto errout; 3529 l1dcp = (struct dmapctl *) l1mp->data; 3530 3531 /* compute start L0 */ 3532 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE; 3533 l1leaf = l1dcp->stree + CTLLEAFIND + j; 3534 p = BLKTOL0(blkno, sbi->l2nbperpage); 3535 j0 = false; 3536 } else { 3537 /* assign/init L1 page */ 3538 l1mp = get_metapage(ipbmap, p, PSIZE, 0); 3539 if (l1mp == NULL) 3540 goto errout; 3541 3542 l1dcp = (struct dmapctl *) l1mp->data; 3543 3544 /* compute start L0 */ 3545 j = 0; 3546 l1leaf = l1dcp->stree + CTLLEAFIND; 3547 p += nbperpage; /* 1st L0 of L1.k */ 3548 } 3549 3550 /* 3551 * extend each L0 in L1 3552 */ 3553 for (; j < LPERCTL; j++) { 3554 /* get L0 page */ 3555 if (i0) { 3556 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */ 3557 3558 l0mp = read_metapage(ipbmap, p, PSIZE, 0); 3559 if (l0mp == NULL) 3560 goto errout; 3561 l0dcp = (struct dmapctl *) l0mp->data; 3562 3563 /* compute start dmap */ 3564 i = (blkno & (MAXL0SIZE - 1)) >> 3565 L2BPERDMAP; 3566 l0leaf = l0dcp->stree + CTLLEAFIND + i; 3567 p = BLKTODMAP(blkno, 3568 sbi->l2nbperpage); 3569 i0 = false; 3570 } else { 3571 /* assign/init L0 page */ 3572 l0mp = get_metapage(ipbmap, p, PSIZE, 0); 3573 if (l0mp == NULL) 3574 goto errout; 3575 3576 l0dcp = (struct dmapctl *) l0mp->data; 3577 3578 /* compute start dmap */ 3579 i = 0; 3580 l0leaf = l0dcp->stree + CTLLEAFIND; 3581 p += nbperpage; /* 1st dmap of L0.j */ 3582 } 3583 3584 /* 3585 * extend each dmap in L0 3586 */ 3587 for (; i < LPERCTL; i++) { 3588 /* 3589 * reconstruct the dmap page, and 3590 * initialize corresponding parent L0 leaf 3591 */ 3592 if ((n = blkno & (BPERDMAP - 1))) { 3593 /* read in dmap page: */ 3594 mp = read_metapage(ipbmap, p, 3595 PSIZE, 0); 3596 if (mp == NULL) 3597 goto errout; 3598 n = min(nblocks, (s64)BPERDMAP - n); 3599 } else { 3600 /* assign/init dmap page */ 3601 mp = read_metapage(ipbmap, p, 3602 PSIZE, 0); 3603 if (mp == NULL) 3604 goto errout; 3605 3606 n = min_t(s64, nblocks, BPERDMAP); 3607 } 3608 3609 dp = (struct dmap *) mp->data; 3610 *l0leaf = dbInitDmap(dp, blkno, n); 3611 3612 bmp->db_nfree += n; 3613 agno = le64_to_cpu(dp->start) >> l2agsize; 3614 bmp->db_agfree[agno] += n; 3615 3616 write_metapage(mp); 3617 3618 l0leaf++; 3619 p += nbperpage; 3620 3621 blkno += n; 3622 nblocks -= n; 3623 if (nblocks == 0) 3624 break; 3625 } /* for each dmap in a L0 */ 3626 3627 /* 3628 * build current L0 page from its leaves, and 3629 * initialize corresponding parent L1 leaf 3630 */ 3631 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i); 3632 write_metapage(l0mp); 3633 l0mp = NULL; 3634 3635 if (nblocks) 3636 l1leaf++; /* continue for next L0 */ 3637 else { 3638 /* more than 1 L0 ? */ 3639 if (j > 0) 3640 break; /* build L1 page */ 3641 else { 3642 /* summarize in global bmap page */ 3643 bmp->db_maxfreebud = *l1leaf; 3644 release_metapage(l1mp); 3645 release_metapage(l2mp); 3646 goto finalize; 3647 } 3648 } 3649 } /* for each L0 in a L1 */ 3650 3651 /* 3652 * build current L1 page from its leaves, and 3653 * initialize corresponding parent L2 leaf 3654 */ 3655 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j); 3656 write_metapage(l1mp); 3657 l1mp = NULL; 3658 3659 if (nblocks) 3660 l2leaf++; /* continue for next L1 */ 3661 else { 3662 /* more than 1 L1 ? */ 3663 if (k > 0) 3664 break; /* build L2 page */ 3665 else { 3666 /* summarize in global bmap page */ 3667 bmp->db_maxfreebud = *l2leaf; 3668 release_metapage(l2mp); 3669 goto finalize; 3670 } 3671 } 3672 } /* for each L1 in a L2 */ 3673 3674 jfs_error(ipbmap->i_sb, "function has not returned as expected\n"); 3675errout: 3676 if (l0mp) 3677 release_metapage(l0mp); 3678 if (l1mp) 3679 release_metapage(l1mp); 3680 release_metapage(l2mp); 3681 return -EIO; 3682 3683 /* 3684 * finalize bmap control page 3685 */ 3686finalize: 3687 3688 return 0; 3689} 3690 3691 3692/* 3693 * dbFinalizeBmap() 3694 */ 3695void dbFinalizeBmap(struct inode *ipbmap) 3696{ 3697 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 3698 int actags, inactags, l2nl; 3699 s64 ag_rem, actfree, inactfree, avgfree; 3700 int i, n; 3701 3702 /* 3703 * finalize bmap control page 3704 */ 3705//finalize: 3706 /* 3707 * compute db_agpref: preferred ag to allocate from 3708 * (the leftmost ag with average free space in it); 3709 */ 3710//agpref: 3711 /* get the number of active ags and inacitve ags */ 3712 actags = bmp->db_maxag + 1; 3713 inactags = bmp->db_numag - actags; 3714 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */ 3715 3716 /* determine how many blocks are in the inactive allocation 3717 * groups. in doing this, we must account for the fact that 3718 * the rightmost group might be a partial group (i.e. file 3719 * system size is not a multiple of the group size). 3720 */ 3721 inactfree = (inactags && ag_rem) ? 3722 ((inactags - 1) << bmp->db_agl2size) + ag_rem 3723 : inactags << bmp->db_agl2size; 3724 3725 /* determine how many free blocks are in the active 3726 * allocation groups plus the average number of free blocks 3727 * within the active ags. 3728 */ 3729 actfree = bmp->db_nfree - inactfree; 3730 avgfree = (u32) actfree / (u32) actags; 3731 3732 /* if the preferred allocation group has not average free space. 3733 * re-establish the preferred group as the leftmost 3734 * group with average free space. 3735 */ 3736 if (bmp->db_agfree[bmp->db_agpref] < avgfree) { 3737 for (bmp->db_agpref = 0; bmp->db_agpref < actags; 3738 bmp->db_agpref++) { 3739 if (bmp->db_agfree[bmp->db_agpref] >= avgfree) 3740 break; 3741 } 3742 if (bmp->db_agpref >= bmp->db_numag) { 3743 jfs_error(ipbmap->i_sb, 3744 "cannot find ag with average freespace\n"); 3745 } 3746 } 3747 3748 /* 3749 * compute db_aglevel, db_agheight, db_width, db_agstart: 3750 * an ag is covered in aglevel dmapctl summary tree, 3751 * at agheight level height (from leaf) with agwidth number of nodes 3752 * each, which starts at agstart index node of the smmary tree node 3753 * array; 3754 */ 3755 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize); 3756 l2nl = 3757 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL); 3758 bmp->db_agheight = l2nl >> 1; 3759 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1)); 3760 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0; 3761 i--) { 3762 bmp->db_agstart += n; 3763 n <<= 2; 3764 } 3765 3766} 3767 3768 3769/* 3770 * NAME: dbInitDmap()/ujfs_idmap_page() 3771 * 3772 * FUNCTION: initialize working/persistent bitmap of the dmap page 3773 * for the specified number of blocks: 3774 * 3775 * at entry, the bitmaps had been initialized as free (ZEROS); 3776 * The number of blocks will only account for the actually 3777 * existing blocks. Blocks which don't actually exist in 3778 * the aggregate will be marked as allocated (ONES); 3779 * 3780 * PARAMETERS: 3781 * dp - pointer to page of map 3782 * nblocks - number of blocks this page 3783 * 3784 * RETURNS: NONE 3785 */ 3786static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks) 3787{ 3788 int blkno, w, b, r, nw, nb, i; 3789 3790 /* starting block number within the dmap */ 3791 blkno = Blkno & (BPERDMAP - 1); 3792 3793 if (blkno == 0) { 3794 dp->nblocks = dp->nfree = cpu_to_le32(nblocks); 3795 dp->start = cpu_to_le64(Blkno); 3796 3797 if (nblocks == BPERDMAP) { 3798 memset(&dp->wmap[0], 0, LPERDMAP * 4); 3799 memset(&dp->pmap[0], 0, LPERDMAP * 4); 3800 goto initTree; 3801 } 3802 } else { 3803 le32_add_cpu(&dp->nblocks, nblocks); 3804 le32_add_cpu(&dp->nfree, nblocks); 3805 } 3806 3807 /* word number containing start block number */ 3808 w = blkno >> L2DBWORD; 3809 3810 /* 3811 * free the bits corresponding to the block range (ZEROS): 3812 * note: not all bits of the first and last words may be contained 3813 * within the block range. 3814 */ 3815 for (r = nblocks; r > 0; r -= nb, blkno += nb) { 3816 /* number of bits preceding range to be freed in the word */ 3817 b = blkno & (DBWORD - 1); 3818 /* number of bits to free in the word */ 3819 nb = min(r, DBWORD - b); 3820 3821 /* is partial word to be freed ? */ 3822 if (nb < DBWORD) { 3823 /* free (set to 0) from the bitmap word */ 3824 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3825 >> b)); 3826 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3827 >> b)); 3828 3829 /* skip the word freed */ 3830 w++; 3831 } else { 3832 /* free (set to 0) contiguous bitmap words */ 3833 nw = r >> L2DBWORD; 3834 memset(&dp->wmap[w], 0, nw * 4); 3835 memset(&dp->pmap[w], 0, nw * 4); 3836 3837 /* skip the words freed */ 3838 nb = nw << L2DBWORD; 3839 w += nw; 3840 } 3841 } 3842 3843 /* 3844 * mark bits following the range to be freed (non-existing 3845 * blocks) as allocated (ONES) 3846 */ 3847 3848 if (blkno == BPERDMAP) 3849 goto initTree; 3850 3851 /* the first word beyond the end of existing blocks */ 3852 w = blkno >> L2DBWORD; 3853 3854 /* does nblocks fall on a 32-bit boundary ? */ 3855 b = blkno & (DBWORD - 1); 3856 if (b) { 3857 /* mark a partial word allocated */ 3858 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b); 3859 w++; 3860 } 3861 3862 /* set the rest of the words in the page to allocated (ONES) */ 3863 for (i = w; i < LPERDMAP; i++) 3864 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES); 3865 3866 /* 3867 * init tree 3868 */ 3869 initTree: 3870 return (dbInitDmapTree(dp)); 3871} 3872 3873 3874/* 3875 * NAME: dbInitDmapTree()/ujfs_complete_dmap() 3876 * 3877 * FUNCTION: initialize summary tree of the specified dmap: 3878 * 3879 * at entry, bitmap of the dmap has been initialized; 3880 * 3881 * PARAMETERS: 3882 * dp - dmap to complete 3883 * blkno - starting block number for this dmap 3884 * treemax - will be filled in with max free for this dmap 3885 * 3886 * RETURNS: max free string at the root of the tree 3887 */ 3888static int dbInitDmapTree(struct dmap * dp) 3889{ 3890 struct dmaptree *tp; 3891 s8 *cp; 3892 int i; 3893 3894 /* init fixed info of tree */ 3895 tp = &dp->tree; 3896 tp->nleafs = cpu_to_le32(LPERDMAP); 3897 tp->l2nleafs = cpu_to_le32(L2LPERDMAP); 3898 tp->leafidx = cpu_to_le32(LEAFIND); 3899 tp->height = cpu_to_le32(4); 3900 tp->budmin = BUDMIN; 3901 3902 /* init each leaf from corresponding wmap word: 3903 * note: leaf is set to NOFREE(-1) if all blocks of corresponding 3904 * bitmap word are allocated. 3905 */ 3906 cp = tp->stree + le32_to_cpu(tp->leafidx); 3907 for (i = 0; i < LPERDMAP; i++) 3908 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]); 3909 3910 /* build the dmap's binary buddy summary tree */ 3911 return (dbInitTree(tp)); 3912} 3913 3914 3915/* 3916 * NAME: dbInitTree()/ujfs_adjtree() 3917 * 3918 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl. 3919 * 3920 * at entry, the leaves of the tree has been initialized 3921 * from corresponding bitmap word or root of summary tree 3922 * of the child control page; 3923 * configure binary buddy system at the leaf level, then 3924 * bubble up the values of the leaf nodes up the tree. 3925 * 3926 * PARAMETERS: 3927 * cp - Pointer to the root of the tree 3928 * l2leaves- Number of leaf nodes as a power of 2 3929 * l2min - Number of blocks that can be covered by a leaf 3930 * as a power of 2 3931 * 3932 * RETURNS: max free string at the root of the tree 3933 */ 3934static int dbInitTree(struct dmaptree * dtp) 3935{ 3936 int l2max, l2free, bsize, nextb, i; 3937 int child, parent, nparent; 3938 s8 *tp, *cp, *cp1; 3939 3940 tp = dtp->stree; 3941 3942 /* Determine the maximum free string possible for the leaves */ 3943 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin; 3944 3945 /* 3946 * configure the leaf levevl into binary buddy system 3947 * 3948 * Try to combine buddies starting with a buddy size of 1 3949 * (i.e. two leaves). At a buddy size of 1 two buddy leaves 3950 * can be combined if both buddies have a maximum free of l2min; 3951 * the combination will result in the left-most buddy leaf having 3952 * a maximum free of l2min+1. 3953 * After processing all buddies for a given size, process buddies 3954 * at the next higher buddy size (i.e. current size * 2) and 3955 * the next maximum free (current free + 1). 3956 * This continues until the maximum possible buddy combination 3957 * yields maximum free. 3958 */ 3959 for (l2free = dtp->budmin, bsize = 1; l2free < l2max; 3960 l2free++, bsize = nextb) { 3961 /* get next buddy size == current buddy pair size */ 3962 nextb = bsize << 1; 3963 3964 /* scan each adjacent buddy pair at current buddy size */ 3965 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx); 3966 i < le32_to_cpu(dtp->nleafs); 3967 i += nextb, cp += nextb) { 3968 /* coalesce if both adjacent buddies are max free */ 3969 if (*cp == l2free && *(cp + bsize) == l2free) { 3970 *cp = l2free + 1; /* left take right */ 3971 *(cp + bsize) = -1; /* right give left */ 3972 } 3973 } 3974 } 3975 3976 /* 3977 * bubble summary information of leaves up the tree. 3978 * 3979 * Starting at the leaf node level, the four nodes described by 3980 * the higher level parent node are compared for a maximum free and 3981 * this maximum becomes the value of the parent node. 3982 * when all lower level nodes are processed in this fashion then 3983 * move up to the next level (parent becomes a lower level node) and 3984 * continue the process for that level. 3985 */ 3986 for (child = le32_to_cpu(dtp->leafidx), 3987 nparent = le32_to_cpu(dtp->nleafs) >> 2; 3988 nparent > 0; nparent >>= 2, child = parent) { 3989 /* get index of 1st node of parent level */ 3990 parent = (child - 1) >> 2; 3991 3992 /* set the value of the parent node as the maximum 3993 * of the four nodes of the current level. 3994 */ 3995 for (i = 0, cp = tp + child, cp1 = tp + parent; 3996 i < nparent; i++, cp += 4, cp1++) 3997 *cp1 = TREEMAX(cp); 3998 } 3999 4000 return (*tp); 4001} 4002 4003 4004/* 4005 * dbInitDmapCtl() 4006 * 4007 * function: initialize dmapctl page 4008 */ 4009static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i) 4010{ /* start leaf index not covered by range */ 4011 s8 *cp; 4012 4013 dcp->nleafs = cpu_to_le32(LPERCTL); 4014 dcp->l2nleafs = cpu_to_le32(L2LPERCTL); 4015 dcp->leafidx = cpu_to_le32(CTLLEAFIND); 4016 dcp->height = cpu_to_le32(5); 4017 dcp->budmin = L2BPERDMAP + L2LPERCTL * level; 4018 4019 /* 4020 * initialize the leaves of current level that were not covered 4021 * by the specified input block range (i.e. the leaves have no 4022 * low level dmapctl or dmap). 4023 */ 4024 cp = &dcp->stree[CTLLEAFIND + i]; 4025 for (; i < LPERCTL; i++) 4026 *cp++ = NOFREE; 4027 4028 /* build the dmap's binary buddy summary tree */ 4029 return (dbInitTree((struct dmaptree *) dcp)); 4030} 4031 4032 4033/* 4034 * NAME: dbGetL2AGSize()/ujfs_getagl2size() 4035 * 4036 * FUNCTION: Determine log2(allocation group size) from aggregate size 4037 * 4038 * PARAMETERS: 4039 * nblocks - Number of blocks in aggregate 4040 * 4041 * RETURNS: log2(allocation group size) in aggregate blocks 4042 */ 4043static int dbGetL2AGSize(s64 nblocks) 4044{ 4045 s64 sz; 4046 s64 m; 4047 int l2sz; 4048 4049 if (nblocks < BPERDMAP * MAXAG) 4050 return (L2BPERDMAP); 4051 4052 /* round up aggregate size to power of 2 */ 4053 m = ((u64) 1 << (64 - 1)); 4054 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) { 4055 if (m & nblocks) 4056 break; 4057 } 4058 4059 sz = (s64) 1 << l2sz; 4060 if (sz < nblocks) 4061 l2sz += 1; 4062 4063 /* agsize = roundupSize/max_number_of_ag */ 4064 return (l2sz - L2MAXAG); 4065} 4066 4067 4068/* 4069 * NAME: dbMapFileSizeToMapSize() 4070 * 4071 * FUNCTION: compute number of blocks the block allocation map file 4072 * can cover from the map file size; 4073 * 4074 * RETURNS: Number of blocks which can be covered by this block map file; 4075 */ 4076 4077/* 4078 * maximum number of map pages at each level including control pages 4079 */ 4080#define MAXL0PAGES (1 + LPERCTL) 4081#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES) 4082 4083/* 4084 * convert number of map pages to the zero origin top dmapctl level 4085 */ 4086#define BMAPPGTOLEV(npages) \ 4087 (((npages) <= 3 + MAXL0PAGES) ? 0 : \ 4088 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2) 4089 4090s64 dbMapFileSizeToMapSize(struct inode * ipbmap) 4091{ 4092 struct super_block *sb = ipbmap->i_sb; 4093 s64 nblocks; 4094 s64 npages, ndmaps; 4095 int level, i; 4096 int complete, factor; 4097 4098 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize; 4099 npages = nblocks >> JFS_SBI(sb)->l2nbperpage; 4100 level = BMAPPGTOLEV(npages); 4101 4102 /* At each level, accumulate the number of dmap pages covered by 4103 * the number of full child levels below it; 4104 * repeat for the last incomplete child level. 4105 */ 4106 ndmaps = 0; 4107 npages--; /* skip the first global control page */ 4108 /* skip higher level control pages above top level covered by map */ 4109 npages -= (2 - level); 4110 npages--; /* skip top level's control page */ 4111 for (i = level; i >= 0; i--) { 4112 factor = 4113 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1); 4114 complete = (u32) npages / factor; 4115 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL : 4116 ((i == 1) ? LPERCTL : 1)); 4117 4118 /* pages in last/incomplete child */ 4119 npages = (u32) npages % factor; 4120 /* skip incomplete child's level control page */ 4121 npages--; 4122 } 4123 4124 /* convert the number of dmaps into the number of blocks 4125 * which can be covered by the dmaps; 4126 */ 4127 nblocks = ndmaps << L2BPERDMAP; 4128 4129 return (nblocks); 4130} 4131