1 /* 2 * Copyright (C) International Business Machines Corp., 2000-2004 3 * Portions Copyright (C) Tino Reichardt, 2012 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 13 * the GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 20 #include <linux/fs.h> 21 #include <linux/slab.h> 22 #include "jfs_incore.h" 23 #include "jfs_superblock.h" 24 #include "jfs_dmap.h" 25 #include "jfs_imap.h" 26 #include "jfs_lock.h" 27 #include "jfs_metapage.h" 28 #include "jfs_debug.h" 29 #include "jfs_discard.h" 30 31 /* 32 * SERIALIZATION of the Block Allocation Map. 33 * 34 * the working state of the block allocation map is accessed in 35 * two directions: 36 * 37 * 1) allocation and free requests that start at the dmap 38 * level and move up through the dmap control pages (i.e. 39 * the vast majority of requests). 40 * 41 * 2) allocation requests that start at dmap control page 42 * level and work down towards the dmaps. 43 * 44 * the serialization scheme used here is as follows. 45 * 46 * requests which start at the bottom are serialized against each 47 * other through buffers and each requests holds onto its buffers 48 * as it works it way up from a single dmap to the required level 49 * of dmap control page. 50 * requests that start at the top are serialized against each other 51 * and request that start from the bottom by the multiple read/single 52 * write inode lock of the bmap inode. requests starting at the top 53 * take this lock in write mode while request starting at the bottom 54 * take the lock in read mode. a single top-down request may proceed 55 * exclusively while multiple bottoms-up requests may proceed 56 * simultaneously (under the protection of busy buffers). 57 * 58 * in addition to information found in dmaps and dmap control pages, 59 * the working state of the block allocation map also includes read/ 60 * write information maintained in the bmap descriptor (i.e. total 61 * free block count, allocation group level free block counts). 62 * a single exclusive lock (BMAP_LOCK) is used to guard this information 63 * in the face of multiple-bottoms up requests. 64 * (lock ordering: IREAD_LOCK, BMAP_LOCK); 65 * 66 * accesses to the persistent state of the block allocation map (limited 67 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers. 68 */ 69 70 #define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock) 71 #define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock) 72 #define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock) 73 74 /* 75 * forward references 76 */ 77 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 78 int nblocks); 79 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval); 80 static int dbBackSplit(dmtree_t * tp, int leafno); 81 static int dbJoin(dmtree_t * tp, int leafno, int newval); 82 static void dbAdjTree(dmtree_t * tp, int leafno, int newval); 83 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, 84 int level); 85 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results); 86 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 87 int nblocks); 88 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno, 89 int nblocks, 90 int l2nb, s64 * results); 91 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 92 int nblocks); 93 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks, 94 int l2nb, 95 s64 * results); 96 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, 97 s64 * results); 98 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, 99 s64 * results); 100 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks); 101 static int dbFindBits(u32 word, int l2nb); 102 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno); 103 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx); 104 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 105 int nblocks); 106 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 107 int nblocks); 108 static int dbMaxBud(u8 * cp); 109 static int blkstol2(s64 nb); 110 111 static int cntlz(u32 value); 112 static int cnttz(u32 word); 113 114 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 115 int nblocks); 116 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks); 117 static int dbInitDmapTree(struct dmap * dp); 118 static int dbInitTree(struct dmaptree * dtp); 119 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i); 120 static int dbGetL2AGSize(s64 nblocks); 121 122 /* 123 * buddy table 124 * 125 * table used for determining buddy sizes within characters of 126 * dmap bitmap words. the characters themselves serve as indexes 127 * into the table, with the table elements yielding the maximum 128 * binary buddy of free bits within the character. 129 */ 130 static const s8 budtab[256] = { 131 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 132 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 133 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 134 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 135 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 136 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 137 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 138 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 139 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 140 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 141 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 142 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 143 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 144 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 145 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 146 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1 147 }; 148 149 /* 150 * NAME: dbMount() 151 * 152 * FUNCTION: initializate the block allocation map. 153 * 154 * memory is allocated for the in-core bmap descriptor and 155 * the in-core descriptor is initialized from disk. 156 * 157 * PARAMETERS: 158 * ipbmap - pointer to in-core inode for the block map. 159 * 160 * RETURN VALUES: 161 * 0 - success 162 * -ENOMEM - insufficient memory 163 * -EIO - i/o error 164 */ 165 int dbMount(struct inode *ipbmap) 166 { 167 struct bmap *bmp; 168 struct dbmap_disk *dbmp_le; 169 struct metapage *mp; 170 int i; 171 172 /* 173 * allocate/initialize the in-memory bmap descriptor 174 */ 175 /* allocate memory for the in-memory bmap descriptor */ 176 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL); 177 if (bmp == NULL) 178 return -ENOMEM; 179 180 /* read the on-disk bmap descriptor. */ 181 mp = read_metapage(ipbmap, 182 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage, 183 PSIZE, 0); 184 if (mp == NULL) { 185 kfree(bmp); 186 return -EIO; 187 } 188 189 /* copy the on-disk bmap descriptor to its in-memory version. */ 190 dbmp_le = (struct dbmap_disk *) mp->data; 191 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize); 192 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree); 193 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage); 194 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag); 195 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); 196 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag); 197 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref); 198 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel); 199 bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight); 200 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth); 201 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart); 202 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size); 203 for (i = 0; i < MAXAG; i++) 204 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]); 205 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize); 206 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud; 207 208 /* release the buffer. */ 209 release_metapage(mp); 210 211 /* bind the bmap inode and the bmap descriptor to each other. */ 212 bmp->db_ipbmap = ipbmap; 213 JFS_SBI(ipbmap->i_sb)->bmap = bmp; 214 215 memset(bmp->db_active, 0, sizeof(bmp->db_active)); 216 217 /* 218 * allocate/initialize the bmap lock 219 */ 220 BMAP_LOCK_INIT(bmp); 221 222 return (0); 223 } 224 225 226 /* 227 * NAME: dbUnmount() 228 * 229 * FUNCTION: terminate the block allocation map in preparation for 230 * file system unmount. 231 * 232 * the in-core bmap descriptor is written to disk and 233 * the memory for this descriptor is freed. 234 * 235 * PARAMETERS: 236 * ipbmap - pointer to in-core inode for the block map. 237 * 238 * RETURN VALUES: 239 * 0 - success 240 * -EIO - i/o error 241 */ 242 int dbUnmount(struct inode *ipbmap, int mounterror) 243 { 244 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 245 246 if (!(mounterror || isReadOnly(ipbmap))) 247 dbSync(ipbmap); 248 249 /* 250 * Invalidate the page cache buffers 251 */ 252 truncate_inode_pages(ipbmap->i_mapping, 0); 253 254 /* free the memory for the in-memory bmap. */ 255 kfree(bmp); 256 257 return (0); 258 } 259 260 /* 261 * dbSync() 262 */ 263 int dbSync(struct inode *ipbmap) 264 { 265 struct dbmap_disk *dbmp_le; 266 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 267 struct metapage *mp; 268 int i; 269 270 /* 271 * write bmap global control page 272 */ 273 /* get the buffer for the on-disk bmap descriptor. */ 274 mp = read_metapage(ipbmap, 275 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage, 276 PSIZE, 0); 277 if (mp == NULL) { 278 jfs_err("dbSync: read_metapage failed!"); 279 return -EIO; 280 } 281 /* copy the in-memory version of the bmap to the on-disk version */ 282 dbmp_le = (struct dbmap_disk *) mp->data; 283 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize); 284 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree); 285 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage); 286 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag); 287 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel); 288 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag); 289 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref); 290 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel); 291 dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight); 292 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth); 293 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart); 294 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size); 295 for (i = 0; i < MAXAG; i++) 296 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]); 297 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize); 298 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud; 299 300 /* write the buffer */ 301 write_metapage(mp); 302 303 /* 304 * write out dirty pages of bmap 305 */ 306 filemap_write_and_wait(ipbmap->i_mapping); 307 308 diWriteSpecial(ipbmap, 0); 309 310 return (0); 311 } 312 313 /* 314 * NAME: dbFree() 315 * 316 * FUNCTION: free the specified block range from the working block 317 * allocation map. 318 * 319 * the blocks will be free from the working map one dmap 320 * at a time. 321 * 322 * PARAMETERS: 323 * ip - pointer to in-core inode; 324 * blkno - starting block number to be freed. 325 * nblocks - number of blocks to be freed. 326 * 327 * RETURN VALUES: 328 * 0 - success 329 * -EIO - i/o error 330 */ 331 int dbFree(struct inode *ip, s64 blkno, s64 nblocks) 332 { 333 struct metapage *mp; 334 struct dmap *dp; 335 int nb, rc; 336 s64 lblkno, rem; 337 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 338 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 339 struct super_block *sb = ipbmap->i_sb; 340 341 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 342 343 /* block to be freed better be within the mapsize. */ 344 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) { 345 IREAD_UNLOCK(ipbmap); 346 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", 347 (unsigned long long) blkno, 348 (unsigned long long) nblocks); 349 jfs_error(ip->i_sb, "block to be freed is outside the map\n"); 350 return -EIO; 351 } 352 353 /** 354 * TRIM the blocks, when mounted with discard option 355 */ 356 if (JFS_SBI(sb)->flag & JFS_DISCARD) 357 if (JFS_SBI(sb)->minblks_trim <= nblocks) 358 jfs_issue_discard(ipbmap, blkno, nblocks); 359 360 /* 361 * free the blocks a dmap at a time. 362 */ 363 mp = NULL; 364 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 365 /* release previous dmap if any */ 366 if (mp) { 367 write_metapage(mp); 368 } 369 370 /* get the buffer for the current dmap. */ 371 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 372 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 373 if (mp == NULL) { 374 IREAD_UNLOCK(ipbmap); 375 return -EIO; 376 } 377 dp = (struct dmap *) mp->data; 378 379 /* determine the number of blocks to be freed from 380 * this dmap. 381 */ 382 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 383 384 /* free the blocks. */ 385 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) { 386 jfs_error(ip->i_sb, "error in block map\n"); 387 release_metapage(mp); 388 IREAD_UNLOCK(ipbmap); 389 return (rc); 390 } 391 } 392 393 /* write the last buffer. */ 394 write_metapage(mp); 395 396 IREAD_UNLOCK(ipbmap); 397 398 return (0); 399 } 400 401 402 /* 403 * NAME: dbUpdatePMap() 404 * 405 * FUNCTION: update the allocation state (free or allocate) of the 406 * specified block range in the persistent block allocation map. 407 * 408 * the blocks will be updated in the persistent map one 409 * dmap at a time. 410 * 411 * PARAMETERS: 412 * ipbmap - pointer to in-core inode for the block map. 413 * free - 'true' if block range is to be freed from the persistent 414 * map; 'false' if it is to be allocated. 415 * blkno - starting block number of the range. 416 * nblocks - number of contiguous blocks in the range. 417 * tblk - transaction block; 418 * 419 * RETURN VALUES: 420 * 0 - success 421 * -EIO - i/o error 422 */ 423 int 424 dbUpdatePMap(struct inode *ipbmap, 425 int free, s64 blkno, s64 nblocks, struct tblock * tblk) 426 { 427 int nblks, dbitno, wbitno, rbits; 428 int word, nbits, nwords; 429 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 430 s64 lblkno, rem, lastlblkno; 431 u32 mask; 432 struct dmap *dp; 433 struct metapage *mp; 434 struct jfs_log *log; 435 int lsn, difft, diffp; 436 unsigned long flags; 437 438 /* the blocks better be within the mapsize. */ 439 if (blkno + nblocks > bmp->db_mapsize) { 440 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", 441 (unsigned long long) blkno, 442 (unsigned long long) nblocks); 443 jfs_error(ipbmap->i_sb, "blocks are outside the map\n"); 444 return -EIO; 445 } 446 447 /* compute delta of transaction lsn from log syncpt */ 448 lsn = tblk->lsn; 449 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log; 450 logdiff(difft, lsn, log); 451 452 /* 453 * update the block state a dmap at a time. 454 */ 455 mp = NULL; 456 lastlblkno = 0; 457 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) { 458 /* get the buffer for the current dmap. */ 459 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 460 if (lblkno != lastlblkno) { 461 if (mp) { 462 write_metapage(mp); 463 } 464 465 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 466 0); 467 if (mp == NULL) 468 return -EIO; 469 metapage_wait_for_io(mp); 470 } 471 dp = (struct dmap *) mp->data; 472 473 /* determine the bit number and word within the dmap of 474 * the starting block. also determine how many blocks 475 * are to be updated within this dmap. 476 */ 477 dbitno = blkno & (BPERDMAP - 1); 478 word = dbitno >> L2DBWORD; 479 nblks = min(rem, (s64)BPERDMAP - dbitno); 480 481 /* update the bits of the dmap words. the first and last 482 * words may only have a subset of their bits updated. if 483 * this is the case, we'll work against that word (i.e. 484 * partial first and/or last) only in a single pass. a 485 * single pass will also be used to update all words that 486 * are to have all their bits updated. 487 */ 488 for (rbits = nblks; rbits > 0; 489 rbits -= nbits, dbitno += nbits) { 490 /* determine the bit number within the word and 491 * the number of bits within the word. 492 */ 493 wbitno = dbitno & (DBWORD - 1); 494 nbits = min(rbits, DBWORD - wbitno); 495 496 /* check if only part of the word is to be updated. */ 497 if (nbits < DBWORD) { 498 /* update (free or allocate) the bits 499 * in this word. 500 */ 501 mask = 502 (ONES << (DBWORD - nbits) >> wbitno); 503 if (free) 504 dp->pmap[word] &= 505 cpu_to_le32(~mask); 506 else 507 dp->pmap[word] |= 508 cpu_to_le32(mask); 509 510 word += 1; 511 } else { 512 /* one or more words are to have all 513 * their bits updated. determine how 514 * many words and how many bits. 515 */ 516 nwords = rbits >> L2DBWORD; 517 nbits = nwords << L2DBWORD; 518 519 /* update (free or allocate) the bits 520 * in these words. 521 */ 522 if (free) 523 memset(&dp->pmap[word], 0, 524 nwords * 4); 525 else 526 memset(&dp->pmap[word], (int) ONES, 527 nwords * 4); 528 529 word += nwords; 530 } 531 } 532 533 /* 534 * update dmap lsn 535 */ 536 if (lblkno == lastlblkno) 537 continue; 538 539 lastlblkno = lblkno; 540 541 LOGSYNC_LOCK(log, flags); 542 if (mp->lsn != 0) { 543 /* inherit older/smaller lsn */ 544 logdiff(diffp, mp->lsn, log); 545 if (difft < diffp) { 546 mp->lsn = lsn; 547 548 /* move bp after tblock in logsync list */ 549 list_move(&mp->synclist, &tblk->synclist); 550 } 551 552 /* inherit younger/larger clsn */ 553 logdiff(difft, tblk->clsn, log); 554 logdiff(diffp, mp->clsn, log); 555 if (difft > diffp) 556 mp->clsn = tblk->clsn; 557 } else { 558 mp->log = log; 559 mp->lsn = lsn; 560 561 /* insert bp after tblock in logsync list */ 562 log->count++; 563 list_add(&mp->synclist, &tblk->synclist); 564 565 mp->clsn = tblk->clsn; 566 } 567 LOGSYNC_UNLOCK(log, flags); 568 } 569 570 /* write the last buffer. */ 571 if (mp) { 572 write_metapage(mp); 573 } 574 575 return (0); 576 } 577 578 579 /* 580 * NAME: dbNextAG() 581 * 582 * FUNCTION: find the preferred allocation group for new allocations. 583 * 584 * Within the allocation groups, we maintain a preferred 585 * allocation group which consists of a group with at least 586 * average free space. It is the preferred group that we target 587 * new inode allocation towards. The tie-in between inode 588 * allocation and block allocation occurs as we allocate the 589 * first (data) block of an inode and specify the inode (block) 590 * as the allocation hint for this block. 591 * 592 * We try to avoid having more than one open file growing in 593 * an allocation group, as this will lead to fragmentation. 594 * This differs from the old OS/2 method of trying to keep 595 * empty ags around for large allocations. 596 * 597 * PARAMETERS: 598 * ipbmap - pointer to in-core inode for the block map. 599 * 600 * RETURN VALUES: 601 * the preferred allocation group number. 602 */ 603 int dbNextAG(struct inode *ipbmap) 604 { 605 s64 avgfree; 606 int agpref; 607 s64 hwm = 0; 608 int i; 609 int next_best = -1; 610 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 611 612 BMAP_LOCK(bmp); 613 614 /* determine the average number of free blocks within the ags. */ 615 avgfree = (u32)bmp->db_nfree / bmp->db_numag; 616 617 /* 618 * if the current preferred ag does not have an active allocator 619 * and has at least average freespace, return it 620 */ 621 agpref = bmp->db_agpref; 622 if ((atomic_read(&bmp->db_active[agpref]) == 0) && 623 (bmp->db_agfree[agpref] >= avgfree)) 624 goto unlock; 625 626 /* From the last preferred ag, find the next one with at least 627 * average free space. 628 */ 629 for (i = 0 ; i < bmp->db_numag; i++, agpref++) { 630 if (agpref == bmp->db_numag) 631 agpref = 0; 632 633 if (atomic_read(&bmp->db_active[agpref])) 634 /* open file is currently growing in this ag */ 635 continue; 636 if (bmp->db_agfree[agpref] >= avgfree) { 637 /* Return this one */ 638 bmp->db_agpref = agpref; 639 goto unlock; 640 } else if (bmp->db_agfree[agpref] > hwm) { 641 /* Less than avg. freespace, but best so far */ 642 hwm = bmp->db_agfree[agpref]; 643 next_best = agpref; 644 } 645 } 646 647 /* 648 * If no inactive ag was found with average freespace, use the 649 * next best 650 */ 651 if (next_best != -1) 652 bmp->db_agpref = next_best; 653 /* else leave db_agpref unchanged */ 654 unlock: 655 BMAP_UNLOCK(bmp); 656 657 /* return the preferred group. 658 */ 659 return (bmp->db_agpref); 660 } 661 662 /* 663 * NAME: dbAlloc() 664 * 665 * FUNCTION: attempt to allocate a specified number of contiguous free 666 * blocks from the working allocation block map. 667 * 668 * the block allocation policy uses hints and a multi-step 669 * approach. 670 * 671 * for allocation requests smaller than the number of blocks 672 * per dmap, we first try to allocate the new blocks 673 * immediately following the hint. if these blocks are not 674 * available, we try to allocate blocks near the hint. if 675 * no blocks near the hint are available, we next try to 676 * allocate within the same dmap as contains the hint. 677 * 678 * if no blocks are available in the dmap or the allocation 679 * request is larger than the dmap size, we try to allocate 680 * within the same allocation group as contains the hint. if 681 * this does not succeed, we finally try to allocate anywhere 682 * within the aggregate. 683 * 684 * we also try to allocate anywhere within the aggregate for 685 * for allocation requests larger than the allocation group 686 * size or requests that specify no hint value. 687 * 688 * PARAMETERS: 689 * ip - pointer to in-core inode; 690 * hint - allocation hint. 691 * nblocks - number of contiguous blocks in the range. 692 * results - on successful return, set to the starting block number 693 * of the newly allocated contiguous range. 694 * 695 * RETURN VALUES: 696 * 0 - success 697 * -ENOSPC - insufficient disk resources 698 * -EIO - i/o error 699 */ 700 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results) 701 { 702 int rc, agno; 703 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 704 struct bmap *bmp; 705 struct metapage *mp; 706 s64 lblkno, blkno; 707 struct dmap *dp; 708 int l2nb; 709 s64 mapSize; 710 int writers; 711 712 /* assert that nblocks is valid */ 713 assert(nblocks > 0); 714 715 /* get the log2 number of blocks to be allocated. 716 * if the number of blocks is not a log2 multiple, 717 * it will be rounded up to the next log2 multiple. 718 */ 719 l2nb = BLKSTOL2(nblocks); 720 721 bmp = JFS_SBI(ip->i_sb)->bmap; 722 723 mapSize = bmp->db_mapsize; 724 725 /* the hint should be within the map */ 726 if (hint >= mapSize) { 727 jfs_error(ip->i_sb, "the hint is outside the map\n"); 728 return -EIO; 729 } 730 731 /* if the number of blocks to be allocated is greater than the 732 * allocation group size, try to allocate anywhere. 733 */ 734 if (l2nb > bmp->db_agl2size) { 735 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 736 737 rc = dbAllocAny(bmp, nblocks, l2nb, results); 738 739 goto write_unlock; 740 } 741 742 /* 743 * If no hint, let dbNextAG recommend an allocation group 744 */ 745 if (hint == 0) 746 goto pref_ag; 747 748 /* we would like to allocate close to the hint. adjust the 749 * hint to the block following the hint since the allocators 750 * will start looking for free space starting at this point. 751 */ 752 blkno = hint + 1; 753 754 if (blkno >= bmp->db_mapsize) 755 goto pref_ag; 756 757 agno = blkno >> bmp->db_agl2size; 758 759 /* check if blkno crosses over into a new allocation group. 760 * if so, check if we should allow allocations within this 761 * allocation group. 762 */ 763 if ((blkno & (bmp->db_agsize - 1)) == 0) 764 /* check if the AG is currently being written to. 765 * if so, call dbNextAG() to find a non-busy 766 * AG with sufficient free space. 767 */ 768 if (atomic_read(&bmp->db_active[agno])) 769 goto pref_ag; 770 771 /* check if the allocation request size can be satisfied from a 772 * single dmap. if so, try to allocate from the dmap containing 773 * the hint using a tiered strategy. 774 */ 775 if (nblocks <= BPERDMAP) { 776 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 777 778 /* get the buffer for the dmap containing the hint. 779 */ 780 rc = -EIO; 781 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 782 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 783 if (mp == NULL) 784 goto read_unlock; 785 786 dp = (struct dmap *) mp->data; 787 788 /* first, try to satisfy the allocation request with the 789 * blocks beginning at the hint. 790 */ 791 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks)) 792 != -ENOSPC) { 793 if (rc == 0) { 794 *results = blkno; 795 mark_metapage_dirty(mp); 796 } 797 798 release_metapage(mp); 799 goto read_unlock; 800 } 801 802 writers = atomic_read(&bmp->db_active[agno]); 803 if ((writers > 1) || 804 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) { 805 /* 806 * Someone else is writing in this allocation 807 * group. To avoid fragmenting, try another ag 808 */ 809 release_metapage(mp); 810 IREAD_UNLOCK(ipbmap); 811 goto pref_ag; 812 } 813 814 /* next, try to satisfy the allocation request with blocks 815 * near the hint. 816 */ 817 if ((rc = 818 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results)) 819 != -ENOSPC) { 820 if (rc == 0) 821 mark_metapage_dirty(mp); 822 823 release_metapage(mp); 824 goto read_unlock; 825 } 826 827 /* try to satisfy the allocation request with blocks within 828 * the same dmap as the hint. 829 */ 830 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results)) 831 != -ENOSPC) { 832 if (rc == 0) 833 mark_metapage_dirty(mp); 834 835 release_metapage(mp); 836 goto read_unlock; 837 } 838 839 release_metapage(mp); 840 IREAD_UNLOCK(ipbmap); 841 } 842 843 /* try to satisfy the allocation request with blocks within 844 * the same allocation group as the hint. 845 */ 846 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 847 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC) 848 goto write_unlock; 849 850 IWRITE_UNLOCK(ipbmap); 851 852 853 pref_ag: 854 /* 855 * Let dbNextAG recommend a preferred allocation group 856 */ 857 agno = dbNextAG(ipbmap); 858 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 859 860 /* Try to allocate within this allocation group. if that fails, try to 861 * allocate anywhere in the map. 862 */ 863 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC) 864 rc = dbAllocAny(bmp, nblocks, l2nb, results); 865 866 write_unlock: 867 IWRITE_UNLOCK(ipbmap); 868 869 return (rc); 870 871 read_unlock: 872 IREAD_UNLOCK(ipbmap); 873 874 return (rc); 875 } 876 877 #ifdef _NOTYET 878 /* 879 * NAME: dbAllocExact() 880 * 881 * FUNCTION: try to allocate the requested extent; 882 * 883 * PARAMETERS: 884 * ip - pointer to in-core inode; 885 * blkno - extent address; 886 * nblocks - extent length; 887 * 888 * RETURN VALUES: 889 * 0 - success 890 * -ENOSPC - insufficient disk resources 891 * -EIO - i/o error 892 */ 893 int dbAllocExact(struct inode *ip, s64 blkno, int nblocks) 894 { 895 int rc; 896 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 897 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 898 struct dmap *dp; 899 s64 lblkno; 900 struct metapage *mp; 901 902 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 903 904 /* 905 * validate extent request: 906 * 907 * note: defragfs policy: 908 * max 64 blocks will be moved. 909 * allocation request size must be satisfied from a single dmap. 910 */ 911 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) { 912 IREAD_UNLOCK(ipbmap); 913 return -EINVAL; 914 } 915 916 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) { 917 /* the free space is no longer available */ 918 IREAD_UNLOCK(ipbmap); 919 return -ENOSPC; 920 } 921 922 /* read in the dmap covering the extent */ 923 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 924 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 925 if (mp == NULL) { 926 IREAD_UNLOCK(ipbmap); 927 return -EIO; 928 } 929 dp = (struct dmap *) mp->data; 930 931 /* try to allocate the requested extent */ 932 rc = dbAllocNext(bmp, dp, blkno, nblocks); 933 934 IREAD_UNLOCK(ipbmap); 935 936 if (rc == 0) 937 mark_metapage_dirty(mp); 938 939 release_metapage(mp); 940 941 return (rc); 942 } 943 #endif /* _NOTYET */ 944 945 /* 946 * NAME: dbReAlloc() 947 * 948 * FUNCTION: attempt to extend a current allocation by a specified 949 * number of blocks. 950 * 951 * this routine attempts to satisfy the allocation request 952 * by first trying to extend the existing allocation in 953 * place by allocating the additional blocks as the blocks 954 * immediately following the current allocation. if these 955 * blocks are not available, this routine will attempt to 956 * allocate a new set of contiguous blocks large enough 957 * to cover the existing allocation plus the additional 958 * number of blocks required. 959 * 960 * PARAMETERS: 961 * ip - pointer to in-core inode requiring allocation. 962 * blkno - starting block of the current allocation. 963 * nblocks - number of contiguous blocks within the current 964 * allocation. 965 * addnblocks - number of blocks to add to the allocation. 966 * results - on successful return, set to the starting block number 967 * of the existing allocation if the existing allocation 968 * was extended in place or to a newly allocated contiguous 969 * range if the existing allocation could not be extended 970 * in place. 971 * 972 * RETURN VALUES: 973 * 0 - success 974 * -ENOSPC - insufficient disk resources 975 * -EIO - i/o error 976 */ 977 int 978 dbReAlloc(struct inode *ip, 979 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results) 980 { 981 int rc; 982 983 /* try to extend the allocation in place. 984 */ 985 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) { 986 *results = blkno; 987 return (0); 988 } else { 989 if (rc != -ENOSPC) 990 return (rc); 991 } 992 993 /* could not extend the allocation in place, so allocate a 994 * new set of blocks for the entire request (i.e. try to get 995 * a range of contiguous blocks large enough to cover the 996 * existing allocation plus the additional blocks.) 997 */ 998 return (dbAlloc 999 (ip, blkno + nblocks - 1, addnblocks + nblocks, results)); 1000 } 1001 1002 1003 /* 1004 * NAME: dbExtend() 1005 * 1006 * FUNCTION: attempt to extend a current allocation by a specified 1007 * number of blocks. 1008 * 1009 * this routine attempts to satisfy the allocation request 1010 * by first trying to extend the existing allocation in 1011 * place by allocating the additional blocks as the blocks 1012 * immediately following the current allocation. 1013 * 1014 * PARAMETERS: 1015 * ip - pointer to in-core inode requiring allocation. 1016 * blkno - starting block of the current allocation. 1017 * nblocks - number of contiguous blocks within the current 1018 * allocation. 1019 * addnblocks - number of blocks to add to the allocation. 1020 * 1021 * RETURN VALUES: 1022 * 0 - success 1023 * -ENOSPC - insufficient disk resources 1024 * -EIO - i/o error 1025 */ 1026 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks) 1027 { 1028 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb); 1029 s64 lblkno, lastblkno, extblkno; 1030 uint rel_block; 1031 struct metapage *mp; 1032 struct dmap *dp; 1033 int rc; 1034 struct inode *ipbmap = sbi->ipbmap; 1035 struct bmap *bmp; 1036 1037 /* 1038 * We don't want a non-aligned extent to cross a page boundary 1039 */ 1040 if (((rel_block = blkno & (sbi->nbperpage - 1))) && 1041 (rel_block + nblocks + addnblocks > sbi->nbperpage)) 1042 return -ENOSPC; 1043 1044 /* get the last block of the current allocation */ 1045 lastblkno = blkno + nblocks - 1; 1046 1047 /* determine the block number of the block following 1048 * the existing allocation. 1049 */ 1050 extblkno = lastblkno + 1; 1051 1052 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 1053 1054 /* better be within the file system */ 1055 bmp = sbi->bmap; 1056 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) { 1057 IREAD_UNLOCK(ipbmap); 1058 jfs_error(ip->i_sb, "the block is outside the filesystem\n"); 1059 return -EIO; 1060 } 1061 1062 /* we'll attempt to extend the current allocation in place by 1063 * allocating the additional blocks as the blocks immediately 1064 * following the current allocation. we only try to extend the 1065 * current allocation in place if the number of additional blocks 1066 * can fit into a dmap, the last block of the current allocation 1067 * is not the last block of the file system, and the start of the 1068 * inplace extension is not on an allocation group boundary. 1069 */ 1070 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize || 1071 (extblkno & (bmp->db_agsize - 1)) == 0) { 1072 IREAD_UNLOCK(ipbmap); 1073 return -ENOSPC; 1074 } 1075 1076 /* get the buffer for the dmap containing the first block 1077 * of the extension. 1078 */ 1079 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage); 1080 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 1081 if (mp == NULL) { 1082 IREAD_UNLOCK(ipbmap); 1083 return -EIO; 1084 } 1085 1086 dp = (struct dmap *) mp->data; 1087 1088 /* try to allocate the blocks immediately following the 1089 * current allocation. 1090 */ 1091 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks); 1092 1093 IREAD_UNLOCK(ipbmap); 1094 1095 /* were we successful ? */ 1096 if (rc == 0) 1097 write_metapage(mp); 1098 else 1099 /* we were not successful */ 1100 release_metapage(mp); 1101 1102 return (rc); 1103 } 1104 1105 1106 /* 1107 * NAME: dbAllocNext() 1108 * 1109 * FUNCTION: attempt to allocate the blocks of the specified block 1110 * range within a dmap. 1111 * 1112 * PARAMETERS: 1113 * bmp - pointer to bmap descriptor 1114 * dp - pointer to dmap. 1115 * blkno - starting block number of the range. 1116 * nblocks - number of contiguous free blocks of the range. 1117 * 1118 * RETURN VALUES: 1119 * 0 - success 1120 * -ENOSPC - insufficient disk resources 1121 * -EIO - i/o error 1122 * 1123 * serialization: IREAD_LOCK(ipbmap) held on entry/exit; 1124 */ 1125 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 1126 int nblocks) 1127 { 1128 int dbitno, word, rembits, nb, nwords, wbitno, nw; 1129 int l2size; 1130 s8 *leaf; 1131 u32 mask; 1132 1133 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { 1134 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); 1135 return -EIO; 1136 } 1137 1138 /* pick up a pointer to the leaves of the dmap tree. 1139 */ 1140 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx); 1141 1142 /* determine the bit number and word within the dmap of the 1143 * starting block. 1144 */ 1145 dbitno = blkno & (BPERDMAP - 1); 1146 word = dbitno >> L2DBWORD; 1147 1148 /* check if the specified block range is contained within 1149 * this dmap. 1150 */ 1151 if (dbitno + nblocks > BPERDMAP) 1152 return -ENOSPC; 1153 1154 /* check if the starting leaf indicates that anything 1155 * is free. 1156 */ 1157 if (leaf[word] == NOFREE) 1158 return -ENOSPC; 1159 1160 /* check the dmaps words corresponding to block range to see 1161 * if the block range is free. not all bits of the first and 1162 * last words may be contained within the block range. if this 1163 * is the case, we'll work against those words (i.e. partial first 1164 * and/or last) on an individual basis (a single pass) and examine 1165 * the actual bits to determine if they are free. a single pass 1166 * will be used for all dmap words fully contained within the 1167 * specified range. within this pass, the leaves of the dmap 1168 * tree will be examined to determine if the blocks are free. a 1169 * single leaf may describe the free space of multiple dmap 1170 * words, so we may visit only a subset of the actual leaves 1171 * corresponding to the dmap words of the block range. 1172 */ 1173 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 1174 /* determine the bit number within the word and 1175 * the number of bits within the word. 1176 */ 1177 wbitno = dbitno & (DBWORD - 1); 1178 nb = min(rembits, DBWORD - wbitno); 1179 1180 /* check if only part of the word is to be examined. 1181 */ 1182 if (nb < DBWORD) { 1183 /* check if the bits are free. 1184 */ 1185 mask = (ONES << (DBWORD - nb) >> wbitno); 1186 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask) 1187 return -ENOSPC; 1188 1189 word += 1; 1190 } else { 1191 /* one or more dmap words are fully contained 1192 * within the block range. determine how many 1193 * words and how many bits. 1194 */ 1195 nwords = rembits >> L2DBWORD; 1196 nb = nwords << L2DBWORD; 1197 1198 /* now examine the appropriate leaves to determine 1199 * if the blocks are free. 1200 */ 1201 while (nwords > 0) { 1202 /* does the leaf describe any free space ? 1203 */ 1204 if (leaf[word] < BUDMIN) 1205 return -ENOSPC; 1206 1207 /* determine the l2 number of bits provided 1208 * by this leaf. 1209 */ 1210 l2size = 1211 min((int)leaf[word], NLSTOL2BSZ(nwords)); 1212 1213 /* determine how many words were handled. 1214 */ 1215 nw = BUDSIZE(l2size, BUDMIN); 1216 1217 nwords -= nw; 1218 word += nw; 1219 } 1220 } 1221 } 1222 1223 /* allocate the blocks. 1224 */ 1225 return (dbAllocDmap(bmp, dp, blkno, nblocks)); 1226 } 1227 1228 1229 /* 1230 * NAME: dbAllocNear() 1231 * 1232 * FUNCTION: attempt to allocate a number of contiguous free blocks near 1233 * a specified block (hint) within a dmap. 1234 * 1235 * starting with the dmap leaf that covers the hint, we'll 1236 * check the next four contiguous leaves for sufficient free 1237 * space. if sufficient free space is found, we'll allocate 1238 * the desired free space. 1239 * 1240 * PARAMETERS: 1241 * bmp - pointer to bmap descriptor 1242 * dp - pointer to dmap. 1243 * blkno - block number to allocate near. 1244 * nblocks - actual number of contiguous free blocks desired. 1245 * l2nb - log2 number of contiguous free blocks desired. 1246 * results - on successful return, set to the starting block number 1247 * of the newly allocated range. 1248 * 1249 * RETURN VALUES: 1250 * 0 - success 1251 * -ENOSPC - insufficient disk resources 1252 * -EIO - i/o error 1253 * 1254 * serialization: IREAD_LOCK(ipbmap) held on entry/exit; 1255 */ 1256 static int 1257 dbAllocNear(struct bmap * bmp, 1258 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results) 1259 { 1260 int word, lword, rc; 1261 s8 *leaf; 1262 1263 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { 1264 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); 1265 return -EIO; 1266 } 1267 1268 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx); 1269 1270 /* determine the word within the dmap that holds the hint 1271 * (i.e. blkno). also, determine the last word in the dmap 1272 * that we'll include in our examination. 1273 */ 1274 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 1275 lword = min(word + 4, LPERDMAP); 1276 1277 /* examine the leaves for sufficient free space. 1278 */ 1279 for (; word < lword; word++) { 1280 /* does the leaf describe sufficient free space ? 1281 */ 1282 if (leaf[word] < l2nb) 1283 continue; 1284 1285 /* determine the block number within the file system 1286 * of the first block described by this dmap word. 1287 */ 1288 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD); 1289 1290 /* if not all bits of the dmap word are free, get the 1291 * starting bit number within the dmap word of the required 1292 * string of free bits and adjust the block number with the 1293 * value. 1294 */ 1295 if (leaf[word] < BUDMIN) 1296 blkno += 1297 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb); 1298 1299 /* allocate the blocks. 1300 */ 1301 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 1302 *results = blkno; 1303 1304 return (rc); 1305 } 1306 1307 return -ENOSPC; 1308 } 1309 1310 1311 /* 1312 * NAME: dbAllocAG() 1313 * 1314 * FUNCTION: attempt to allocate the specified number of contiguous 1315 * free blocks within the specified allocation group. 1316 * 1317 * unless the allocation group size is equal to the number 1318 * of blocks per dmap, the dmap control pages will be used to 1319 * find the required free space, if available. we start the 1320 * search at the highest dmap control page level which 1321 * distinctly describes the allocation group's free space 1322 * (i.e. the highest level at which the allocation group's 1323 * free space is not mixed in with that of any other group). 1324 * in addition, we start the search within this level at a 1325 * height of the dmapctl dmtree at which the nodes distinctly 1326 * describe the allocation group's free space. at this height, 1327 * the allocation group's free space may be represented by 1 1328 * or two sub-trees, depending on the allocation group size. 1329 * we search the top nodes of these subtrees left to right for 1330 * sufficient free space. if sufficient free space is found, 1331 * the subtree is searched to find the leftmost leaf that 1332 * has free space. once we have made it to the leaf, we 1333 * move the search to the next lower level dmap control page 1334 * corresponding to this leaf. we continue down the dmap control 1335 * pages until we find the dmap that contains or starts the 1336 * sufficient free space and we allocate at this dmap. 1337 * 1338 * if the allocation group size is equal to the dmap size, 1339 * we'll start at the dmap corresponding to the allocation 1340 * group and attempt the allocation at this level. 1341 * 1342 * the dmap control page search is also not performed if the 1343 * allocation group is completely free and we go to the first 1344 * dmap of the allocation group to do the allocation. this is 1345 * done because the allocation group may be part (not the first 1346 * part) of a larger binary buddy system, causing the dmap 1347 * control pages to indicate no free space (NOFREE) within 1348 * the allocation group. 1349 * 1350 * PARAMETERS: 1351 * bmp - pointer to bmap descriptor 1352 * agno - allocation group number. 1353 * nblocks - actual number of contiguous free blocks desired. 1354 * l2nb - log2 number of contiguous free blocks desired. 1355 * results - on successful return, set to the starting block number 1356 * of the newly allocated range. 1357 * 1358 * RETURN VALUES: 1359 * 0 - success 1360 * -ENOSPC - insufficient disk resources 1361 * -EIO - i/o error 1362 * 1363 * note: IWRITE_LOCK(ipmap) held on entry/exit; 1364 */ 1365 static int 1366 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results) 1367 { 1368 struct metapage *mp; 1369 struct dmapctl *dcp; 1370 int rc, ti, i, k, m, n, agperlev; 1371 s64 blkno, lblkno; 1372 int budmin; 1373 1374 /* allocation request should not be for more than the 1375 * allocation group size. 1376 */ 1377 if (l2nb > bmp->db_agl2size) { 1378 jfs_error(bmp->db_ipbmap->i_sb, 1379 "allocation request is larger than the allocation group size\n"); 1380 return -EIO; 1381 } 1382 1383 /* determine the starting block number of the allocation 1384 * group. 1385 */ 1386 blkno = (s64) agno << bmp->db_agl2size; 1387 1388 /* check if the allocation group size is the minimum allocation 1389 * group size or if the allocation group is completely free. if 1390 * the allocation group size is the minimum size of BPERDMAP (i.e. 1391 * 1 dmap), there is no need to search the dmap control page (below) 1392 * that fully describes the allocation group since the allocation 1393 * group is already fully described by a dmap. in this case, we 1394 * just call dbAllocCtl() to search the dmap tree and allocate the 1395 * required space if available. 1396 * 1397 * if the allocation group is completely free, dbAllocCtl() is 1398 * also called to allocate the required space. this is done for 1399 * two reasons. first, it makes no sense searching the dmap control 1400 * pages for free space when we know that free space exists. second, 1401 * the dmap control pages may indicate that the allocation group 1402 * has no free space if the allocation group is part (not the first 1403 * part) of a larger binary buddy system. 1404 */ 1405 if (bmp->db_agsize == BPERDMAP 1406 || bmp->db_agfree[agno] == bmp->db_agsize) { 1407 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1408 if ((rc == -ENOSPC) && 1409 (bmp->db_agfree[agno] == bmp->db_agsize)) { 1410 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n", 1411 (unsigned long long) blkno, 1412 (unsigned long long) nblocks); 1413 jfs_error(bmp->db_ipbmap->i_sb, 1414 "dbAllocCtl failed in free AG\n"); 1415 } 1416 return (rc); 1417 } 1418 1419 /* the buffer for the dmap control page that fully describes the 1420 * allocation group. 1421 */ 1422 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel); 1423 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1424 if (mp == NULL) 1425 return -EIO; 1426 dcp = (struct dmapctl *) mp->data; 1427 budmin = dcp->budmin; 1428 1429 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1430 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 1431 release_metapage(mp); 1432 return -EIO; 1433 } 1434 1435 /* search the subtree(s) of the dmap control page that describes 1436 * the allocation group, looking for sufficient free space. to begin, 1437 * determine how many allocation groups are represented in a dmap 1438 * control page at the control page level (i.e. L0, L1, L2) that 1439 * fully describes an allocation group. next, determine the starting 1440 * tree index of this allocation group within the control page. 1441 */ 1442 agperlev = 1443 (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth; 1444 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1)); 1445 1446 /* dmap control page trees fan-out by 4 and a single allocation 1447 * group may be described by 1 or 2 subtrees within the ag level 1448 * dmap control page, depending upon the ag size. examine the ag's 1449 * subtrees for sufficient free space, starting with the leftmost 1450 * subtree. 1451 */ 1452 for (i = 0; i < bmp->db_agwidth; i++, ti++) { 1453 /* is there sufficient free space ? 1454 */ 1455 if (l2nb > dcp->stree[ti]) 1456 continue; 1457 1458 /* sufficient free space found in a subtree. now search down 1459 * the subtree to find the leftmost leaf that describes this 1460 * free space. 1461 */ 1462 for (k = bmp->db_agheight; k > 0; k--) { 1463 for (n = 0, m = (ti << 2) + 1; n < 4; n++) { 1464 if (l2nb <= dcp->stree[m + n]) { 1465 ti = m + n; 1466 break; 1467 } 1468 } 1469 if (n == 4) { 1470 jfs_error(bmp->db_ipbmap->i_sb, 1471 "failed descending stree\n"); 1472 release_metapage(mp); 1473 return -EIO; 1474 } 1475 } 1476 1477 /* determine the block number within the file system 1478 * that corresponds to this leaf. 1479 */ 1480 if (bmp->db_aglevel == 2) 1481 blkno = 0; 1482 else if (bmp->db_aglevel == 1) 1483 blkno &= ~(MAXL1SIZE - 1); 1484 else /* bmp->db_aglevel == 0 */ 1485 blkno &= ~(MAXL0SIZE - 1); 1486 1487 blkno += 1488 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin; 1489 1490 /* release the buffer in preparation for going down 1491 * the next level of dmap control pages. 1492 */ 1493 release_metapage(mp); 1494 1495 /* check if we need to continue to search down the lower 1496 * level dmap control pages. we need to if the number of 1497 * blocks required is less than maximum number of blocks 1498 * described at the next lower level. 1499 */ 1500 if (l2nb < budmin) { 1501 1502 /* search the lower level dmap control pages to get 1503 * the starting block number of the dmap that 1504 * contains or starts off the free space. 1505 */ 1506 if ((rc = 1507 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1, 1508 &blkno))) { 1509 if (rc == -ENOSPC) { 1510 jfs_error(bmp->db_ipbmap->i_sb, 1511 "control page inconsistent\n"); 1512 return -EIO; 1513 } 1514 return (rc); 1515 } 1516 } 1517 1518 /* allocate the blocks. 1519 */ 1520 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1521 if (rc == -ENOSPC) { 1522 jfs_error(bmp->db_ipbmap->i_sb, 1523 "unable to allocate blocks\n"); 1524 rc = -EIO; 1525 } 1526 return (rc); 1527 } 1528 1529 /* no space in the allocation group. release the buffer and 1530 * return -ENOSPC. 1531 */ 1532 release_metapage(mp); 1533 1534 return -ENOSPC; 1535 } 1536 1537 1538 /* 1539 * NAME: dbAllocAny() 1540 * 1541 * FUNCTION: attempt to allocate the specified number of contiguous 1542 * free blocks anywhere in the file system. 1543 * 1544 * dbAllocAny() attempts to find the sufficient free space by 1545 * searching down the dmap control pages, starting with the 1546 * highest level (i.e. L0, L1, L2) control page. if free space 1547 * large enough to satisfy the desired free space is found, the 1548 * desired free space is allocated. 1549 * 1550 * PARAMETERS: 1551 * bmp - pointer to bmap descriptor 1552 * nblocks - actual number of contiguous free blocks desired. 1553 * l2nb - log2 number of contiguous free blocks desired. 1554 * results - on successful return, set to the starting block number 1555 * of the newly allocated range. 1556 * 1557 * RETURN VALUES: 1558 * 0 - success 1559 * -ENOSPC - insufficient disk resources 1560 * -EIO - i/o error 1561 * 1562 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1563 */ 1564 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results) 1565 { 1566 int rc; 1567 s64 blkno = 0; 1568 1569 /* starting with the top level dmap control page, search 1570 * down the dmap control levels for sufficient free space. 1571 * if free space is found, dbFindCtl() returns the starting 1572 * block number of the dmap that contains or starts off the 1573 * range of free space. 1574 */ 1575 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno))) 1576 return (rc); 1577 1578 /* allocate the blocks. 1579 */ 1580 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1581 if (rc == -ENOSPC) { 1582 jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n"); 1583 return -EIO; 1584 } 1585 return (rc); 1586 } 1587 1588 1589 /* 1590 * NAME: dbDiscardAG() 1591 * 1592 * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG 1593 * 1594 * algorithm: 1595 * 1) allocate blocks, as large as possible and save them 1596 * while holding IWRITE_LOCK on ipbmap 1597 * 2) trim all these saved block/length values 1598 * 3) mark the blocks free again 1599 * 1600 * benefit: 1601 * - we work only on one ag at some time, minimizing how long we 1602 * need to lock ipbmap 1603 * - reading / writing the fs is possible most time, even on 1604 * trimming 1605 * 1606 * downside: 1607 * - we write two times to the dmapctl and dmap pages 1608 * - but for me, this seems the best way, better ideas? 1609 * /TR 2012 1610 * 1611 * PARAMETERS: 1612 * ip - pointer to in-core inode 1613 * agno - ag to trim 1614 * minlen - minimum value of contiguous blocks 1615 * 1616 * RETURN VALUES: 1617 * s64 - actual number of blocks trimmed 1618 */ 1619 s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen) 1620 { 1621 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 1622 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 1623 s64 nblocks, blkno; 1624 u64 trimmed = 0; 1625 int rc, l2nb; 1626 struct super_block *sb = ipbmap->i_sb; 1627 1628 struct range2trim { 1629 u64 blkno; 1630 u64 nblocks; 1631 } *totrim, *tt; 1632 1633 /* max blkno / nblocks pairs to trim */ 1634 int count = 0, range_cnt; 1635 u64 max_ranges; 1636 1637 /* prevent others from writing new stuff here, while trimming */ 1638 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 1639 1640 nblocks = bmp->db_agfree[agno]; 1641 max_ranges = nblocks; 1642 do_div(max_ranges, minlen); 1643 range_cnt = min_t(u64, max_ranges + 1, 32 * 1024); 1644 totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS); 1645 if (totrim == NULL) { 1646 jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n"); 1647 IWRITE_UNLOCK(ipbmap); 1648 return 0; 1649 } 1650 1651 tt = totrim; 1652 while (nblocks >= minlen) { 1653 l2nb = BLKSTOL2(nblocks); 1654 1655 /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */ 1656 rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno); 1657 if (rc == 0) { 1658 tt->blkno = blkno; 1659 tt->nblocks = nblocks; 1660 tt++; count++; 1661 1662 /* the whole ag is free, trim now */ 1663 if (bmp->db_agfree[agno] == 0) 1664 break; 1665 1666 /* give a hint for the next while */ 1667 nblocks = bmp->db_agfree[agno]; 1668 continue; 1669 } else if (rc == -ENOSPC) { 1670 /* search for next smaller log2 block */ 1671 l2nb = BLKSTOL2(nblocks) - 1; 1672 nblocks = 1 << l2nb; 1673 } else { 1674 /* Trim any already allocated blocks */ 1675 jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n"); 1676 break; 1677 } 1678 1679 /* check, if our trim array is full */ 1680 if (unlikely(count >= range_cnt - 1)) 1681 break; 1682 } 1683 IWRITE_UNLOCK(ipbmap); 1684 1685 tt->nblocks = 0; /* mark the current end */ 1686 for (tt = totrim; tt->nblocks != 0; tt++) { 1687 /* when mounted with online discard, dbFree() will 1688 * call jfs_issue_discard() itself */ 1689 if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) 1690 jfs_issue_discard(ip, tt->blkno, tt->nblocks); 1691 dbFree(ip, tt->blkno, tt->nblocks); 1692 trimmed += tt->nblocks; 1693 } 1694 kfree(totrim); 1695 1696 return trimmed; 1697 } 1698 1699 /* 1700 * NAME: dbFindCtl() 1701 * 1702 * FUNCTION: starting at a specified dmap control page level and block 1703 * number, search down the dmap control levels for a range of 1704 * contiguous free blocks large enough to satisfy an allocation 1705 * request for the specified number of free blocks. 1706 * 1707 * if sufficient contiguous free blocks are found, this routine 1708 * returns the starting block number within a dmap page that 1709 * contains or starts a range of contiqious free blocks that 1710 * is sufficient in size. 1711 * 1712 * PARAMETERS: 1713 * bmp - pointer to bmap descriptor 1714 * level - starting dmap control page level. 1715 * l2nb - log2 number of contiguous free blocks desired. 1716 * *blkno - on entry, starting block number for conducting the search. 1717 * on successful return, the first block within a dmap page 1718 * that contains or starts a range of contiguous free blocks. 1719 * 1720 * RETURN VALUES: 1721 * 0 - success 1722 * -ENOSPC - insufficient disk resources 1723 * -EIO - i/o error 1724 * 1725 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1726 */ 1727 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno) 1728 { 1729 int rc, leafidx, lev; 1730 s64 b, lblkno; 1731 struct dmapctl *dcp; 1732 int budmin; 1733 struct metapage *mp; 1734 1735 /* starting at the specified dmap control page level and block 1736 * number, search down the dmap control levels for the starting 1737 * block number of a dmap page that contains or starts off 1738 * sufficient free blocks. 1739 */ 1740 for (lev = level, b = *blkno; lev >= 0; lev--) { 1741 /* get the buffer of the dmap control page for the block 1742 * number and level (i.e. L0, L1, L2). 1743 */ 1744 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev); 1745 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1746 if (mp == NULL) 1747 return -EIO; 1748 dcp = (struct dmapctl *) mp->data; 1749 budmin = dcp->budmin; 1750 1751 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1752 jfs_error(bmp->db_ipbmap->i_sb, 1753 "Corrupt dmapctl page\n"); 1754 release_metapage(mp); 1755 return -EIO; 1756 } 1757 1758 /* search the tree within the dmap control page for 1759 * sufficient free space. if sufficient free space is found, 1760 * dbFindLeaf() returns the index of the leaf at which 1761 * free space was found. 1762 */ 1763 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx); 1764 1765 /* release the buffer. 1766 */ 1767 release_metapage(mp); 1768 1769 /* space found ? 1770 */ 1771 if (rc) { 1772 if (lev != level) { 1773 jfs_error(bmp->db_ipbmap->i_sb, 1774 "dmap inconsistent\n"); 1775 return -EIO; 1776 } 1777 return -ENOSPC; 1778 } 1779 1780 /* adjust the block number to reflect the location within 1781 * the dmap control page (i.e. the leaf) at which free 1782 * space was found. 1783 */ 1784 b += (((s64) leafidx) << budmin); 1785 1786 /* we stop the search at this dmap control page level if 1787 * the number of blocks required is greater than or equal 1788 * to the maximum number of blocks described at the next 1789 * (lower) level. 1790 */ 1791 if (l2nb >= budmin) 1792 break; 1793 } 1794 1795 *blkno = b; 1796 return (0); 1797 } 1798 1799 1800 /* 1801 * NAME: dbAllocCtl() 1802 * 1803 * FUNCTION: attempt to allocate a specified number of contiguous 1804 * blocks starting within a specific dmap. 1805 * 1806 * this routine is called by higher level routines that search 1807 * the dmap control pages above the actual dmaps for contiguous 1808 * free space. the result of successful searches by these 1809 * routines are the starting block numbers within dmaps, with 1810 * the dmaps themselves containing the desired contiguous free 1811 * space or starting a contiguous free space of desired size 1812 * that is made up of the blocks of one or more dmaps. these 1813 * calls should not fail due to insufficent resources. 1814 * 1815 * this routine is called in some cases where it is not known 1816 * whether it will fail due to insufficient resources. more 1817 * specifically, this occurs when allocating from an allocation 1818 * group whose size is equal to the number of blocks per dmap. 1819 * in this case, the dmap control pages are not examined prior 1820 * to calling this routine (to save pathlength) and the call 1821 * might fail. 1822 * 1823 * for a request size that fits within a dmap, this routine relies 1824 * upon the dmap's dmtree to find the requested contiguous free 1825 * space. for request sizes that are larger than a dmap, the 1826 * requested free space will start at the first block of the 1827 * first dmap (i.e. blkno). 1828 * 1829 * PARAMETERS: 1830 * bmp - pointer to bmap descriptor 1831 * nblocks - actual number of contiguous free blocks to allocate. 1832 * l2nb - log2 number of contiguous free blocks to allocate. 1833 * blkno - starting block number of the dmap to start the allocation 1834 * from. 1835 * results - on successful return, set to the starting block number 1836 * of the newly allocated range. 1837 * 1838 * RETURN VALUES: 1839 * 0 - success 1840 * -ENOSPC - insufficient disk resources 1841 * -EIO - i/o error 1842 * 1843 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1844 */ 1845 static int 1846 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results) 1847 { 1848 int rc, nb; 1849 s64 b, lblkno, n; 1850 struct metapage *mp; 1851 struct dmap *dp; 1852 1853 /* check if the allocation request is confined to a single dmap. 1854 */ 1855 if (l2nb <= L2BPERDMAP) { 1856 /* get the buffer for the dmap. 1857 */ 1858 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 1859 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1860 if (mp == NULL) 1861 return -EIO; 1862 dp = (struct dmap *) mp->data; 1863 1864 /* try to allocate the blocks. 1865 */ 1866 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results); 1867 if (rc == 0) 1868 mark_metapage_dirty(mp); 1869 1870 release_metapage(mp); 1871 1872 return (rc); 1873 } 1874 1875 /* allocation request involving multiple dmaps. it must start on 1876 * a dmap boundary. 1877 */ 1878 assert((blkno & (BPERDMAP - 1)) == 0); 1879 1880 /* allocate the blocks dmap by dmap. 1881 */ 1882 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) { 1883 /* get the buffer for the dmap. 1884 */ 1885 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1886 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1887 if (mp == NULL) { 1888 rc = -EIO; 1889 goto backout; 1890 } 1891 dp = (struct dmap *) mp->data; 1892 1893 /* the dmap better be all free. 1894 */ 1895 if (dp->tree.stree[ROOT] != L2BPERDMAP) { 1896 release_metapage(mp); 1897 jfs_error(bmp->db_ipbmap->i_sb, 1898 "the dmap is not all free\n"); 1899 rc = -EIO; 1900 goto backout; 1901 } 1902 1903 /* determine how many blocks to allocate from this dmap. 1904 */ 1905 nb = min(n, (s64)BPERDMAP); 1906 1907 /* allocate the blocks from the dmap. 1908 */ 1909 if ((rc = dbAllocDmap(bmp, dp, b, nb))) { 1910 release_metapage(mp); 1911 goto backout; 1912 } 1913 1914 /* write the buffer. 1915 */ 1916 write_metapage(mp); 1917 } 1918 1919 /* set the results (starting block number) and return. 1920 */ 1921 *results = blkno; 1922 return (0); 1923 1924 /* something failed in handling an allocation request involving 1925 * multiple dmaps. we'll try to clean up by backing out any 1926 * allocation that has already happened for this request. if 1927 * we fail in backing out the allocation, we'll mark the file 1928 * system to indicate that blocks have been leaked. 1929 */ 1930 backout: 1931 1932 /* try to backout the allocations dmap by dmap. 1933 */ 1934 for (n = nblocks - n, b = blkno; n > 0; 1935 n -= BPERDMAP, b += BPERDMAP) { 1936 /* get the buffer for this dmap. 1937 */ 1938 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1939 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1940 if (mp == NULL) { 1941 /* could not back out. mark the file system 1942 * to indicate that we have leaked blocks. 1943 */ 1944 jfs_error(bmp->db_ipbmap->i_sb, 1945 "I/O Error: Block Leakage\n"); 1946 continue; 1947 } 1948 dp = (struct dmap *) mp->data; 1949 1950 /* free the blocks is this dmap. 1951 */ 1952 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) { 1953 /* could not back out. mark the file system 1954 * to indicate that we have leaked blocks. 1955 */ 1956 release_metapage(mp); 1957 jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n"); 1958 continue; 1959 } 1960 1961 /* write the buffer. 1962 */ 1963 write_metapage(mp); 1964 } 1965 1966 return (rc); 1967 } 1968 1969 1970 /* 1971 * NAME: dbAllocDmapLev() 1972 * 1973 * FUNCTION: attempt to allocate a specified number of contiguous blocks 1974 * from a specified dmap. 1975 * 1976 * this routine checks if the contiguous blocks are available. 1977 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is 1978 * returned. 1979 * 1980 * PARAMETERS: 1981 * mp - pointer to bmap descriptor 1982 * dp - pointer to dmap to attempt to allocate blocks from. 1983 * l2nb - log2 number of contiguous block desired. 1984 * nblocks - actual number of contiguous block desired. 1985 * results - on successful return, set to the starting block number 1986 * of the newly allocated range. 1987 * 1988 * RETURN VALUES: 1989 * 0 - success 1990 * -ENOSPC - insufficient disk resources 1991 * -EIO - i/o error 1992 * 1993 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or 1994 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit; 1995 */ 1996 static int 1997 dbAllocDmapLev(struct bmap * bmp, 1998 struct dmap * dp, int nblocks, int l2nb, s64 * results) 1999 { 2000 s64 blkno; 2001 int leafidx, rc; 2002 2003 /* can't be more than a dmaps worth of blocks */ 2004 assert(l2nb <= L2BPERDMAP); 2005 2006 /* search the tree within the dmap page for sufficient 2007 * free space. if sufficient free space is found, dbFindLeaf() 2008 * returns the index of the leaf at which free space was found. 2009 */ 2010 if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx)) 2011 return -ENOSPC; 2012 2013 /* determine the block number within the file system corresponding 2014 * to the leaf at which free space was found. 2015 */ 2016 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD); 2017 2018 /* if not all bits of the dmap word are free, get the starting 2019 * bit number within the dmap word of the required string of free 2020 * bits and adjust the block number with this value. 2021 */ 2022 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN) 2023 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb); 2024 2025 /* allocate the blocks */ 2026 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 2027 *results = blkno; 2028 2029 return (rc); 2030 } 2031 2032 2033 /* 2034 * NAME: dbAllocDmap() 2035 * 2036 * FUNCTION: adjust the disk allocation map to reflect the allocation 2037 * of a specified block range within a dmap. 2038 * 2039 * this routine allocates the specified blocks from the dmap 2040 * through a call to dbAllocBits(). if the allocation of the 2041 * block range causes the maximum string of free blocks within 2042 * the dmap to change (i.e. the value of the root of the dmap's 2043 * dmtree), this routine will cause this change to be reflected 2044 * up through the appropriate levels of the dmap control pages 2045 * by a call to dbAdjCtl() for the L0 dmap control page that 2046 * covers this dmap. 2047 * 2048 * PARAMETERS: 2049 * bmp - pointer to bmap descriptor 2050 * dp - pointer to dmap to allocate the block range from. 2051 * blkno - starting block number of the block to be allocated. 2052 * nblocks - number of blocks to be allocated. 2053 * 2054 * RETURN VALUES: 2055 * 0 - success 2056 * -EIO - i/o error 2057 * 2058 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2059 */ 2060 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2061 int nblocks) 2062 { 2063 s8 oldroot; 2064 int rc; 2065 2066 /* save the current value of the root (i.e. maximum free string) 2067 * of the dmap tree. 2068 */ 2069 oldroot = dp->tree.stree[ROOT]; 2070 2071 /* allocate the specified (blocks) bits */ 2072 dbAllocBits(bmp, dp, blkno, nblocks); 2073 2074 /* if the root has not changed, done. */ 2075 if (dp->tree.stree[ROOT] == oldroot) 2076 return (0); 2077 2078 /* root changed. bubble the change up to the dmap control pages. 2079 * if the adjustment of the upper level control pages fails, 2080 * backout the bit allocation (thus making everything consistent). 2081 */ 2082 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0))) 2083 dbFreeBits(bmp, dp, blkno, nblocks); 2084 2085 return (rc); 2086 } 2087 2088 2089 /* 2090 * NAME: dbFreeDmap() 2091 * 2092 * FUNCTION: adjust the disk allocation map to reflect the allocation 2093 * of a specified block range within a dmap. 2094 * 2095 * this routine frees the specified blocks from the dmap through 2096 * a call to dbFreeBits(). if the deallocation of the block range 2097 * causes the maximum string of free blocks within the dmap to 2098 * change (i.e. the value of the root of the dmap's dmtree), this 2099 * routine will cause this change to be reflected up through the 2100 * appropriate levels of the dmap control pages by a call to 2101 * dbAdjCtl() for the L0 dmap control page that covers this dmap. 2102 * 2103 * PARAMETERS: 2104 * bmp - pointer to bmap descriptor 2105 * dp - pointer to dmap to free the block range from. 2106 * blkno - starting block number of the block to be freed. 2107 * nblocks - number of blocks to be freed. 2108 * 2109 * RETURN VALUES: 2110 * 0 - success 2111 * -EIO - i/o error 2112 * 2113 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2114 */ 2115 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2116 int nblocks) 2117 { 2118 s8 oldroot; 2119 int rc = 0, word; 2120 2121 /* save the current value of the root (i.e. maximum free string) 2122 * of the dmap tree. 2123 */ 2124 oldroot = dp->tree.stree[ROOT]; 2125 2126 /* free the specified (blocks) bits */ 2127 rc = dbFreeBits(bmp, dp, blkno, nblocks); 2128 2129 /* if error or the root has not changed, done. */ 2130 if (rc || (dp->tree.stree[ROOT] == oldroot)) 2131 return (rc); 2132 2133 /* root changed. bubble the change up to the dmap control pages. 2134 * if the adjustment of the upper level control pages fails, 2135 * backout the deallocation. 2136 */ 2137 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) { 2138 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 2139 2140 /* as part of backing out the deallocation, we will have 2141 * to back split the dmap tree if the deallocation caused 2142 * the freed blocks to become part of a larger binary buddy 2143 * system. 2144 */ 2145 if (dp->tree.stree[word] == NOFREE) 2146 dbBackSplit((dmtree_t *) & dp->tree, word); 2147 2148 dbAllocBits(bmp, dp, blkno, nblocks); 2149 } 2150 2151 return (rc); 2152 } 2153 2154 2155 /* 2156 * NAME: dbAllocBits() 2157 * 2158 * FUNCTION: allocate a specified block range from a dmap. 2159 * 2160 * this routine updates the dmap to reflect the working 2161 * state allocation of the specified block range. it directly 2162 * updates the bits of the working map and causes the adjustment 2163 * of the binary buddy system described by the dmap's dmtree 2164 * leaves to reflect the bits allocated. it also causes the 2165 * dmap's dmtree, as a whole, to reflect the allocated range. 2166 * 2167 * PARAMETERS: 2168 * bmp - pointer to bmap descriptor 2169 * dp - pointer to dmap to allocate bits from. 2170 * blkno - starting block number of the bits to be allocated. 2171 * nblocks - number of bits to be allocated. 2172 * 2173 * RETURN VALUES: none 2174 * 2175 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2176 */ 2177 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2178 int nblocks) 2179 { 2180 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2181 dmtree_t *tp = (dmtree_t *) & dp->tree; 2182 int size; 2183 s8 *leaf; 2184 2185 /* pick up a pointer to the leaves of the dmap tree */ 2186 leaf = dp->tree.stree + LEAFIND; 2187 2188 /* determine the bit number and word within the dmap of the 2189 * starting block. 2190 */ 2191 dbitno = blkno & (BPERDMAP - 1); 2192 word = dbitno >> L2DBWORD; 2193 2194 /* block range better be within the dmap */ 2195 assert(dbitno + nblocks <= BPERDMAP); 2196 2197 /* allocate the bits of the dmap's words corresponding to the block 2198 * range. not all bits of the first and last words may be contained 2199 * within the block range. if this is the case, we'll work against 2200 * those words (i.e. partial first and/or last) on an individual basis 2201 * (a single pass), allocating the bits of interest by hand and 2202 * updating the leaf corresponding to the dmap word. a single pass 2203 * will be used for all dmap words fully contained within the 2204 * specified range. within this pass, the bits of all fully contained 2205 * dmap words will be marked as free in a single shot and the leaves 2206 * will be updated. a single leaf may describe the free space of 2207 * multiple dmap words, so we may update only a subset of the actual 2208 * leaves corresponding to the dmap words of the block range. 2209 */ 2210 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2211 /* determine the bit number within the word and 2212 * the number of bits within the word. 2213 */ 2214 wbitno = dbitno & (DBWORD - 1); 2215 nb = min(rembits, DBWORD - wbitno); 2216 2217 /* check if only part of a word is to be allocated. 2218 */ 2219 if (nb < DBWORD) { 2220 /* allocate (set to 1) the appropriate bits within 2221 * this dmap word. 2222 */ 2223 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 2224 >> wbitno); 2225 2226 /* update the leaf for this dmap word. in addition 2227 * to setting the leaf value to the binary buddy max 2228 * of the updated dmap word, dbSplit() will split 2229 * the binary system of the leaves if need be. 2230 */ 2231 dbSplit(tp, word, BUDMIN, 2232 dbMaxBud((u8 *) & dp->wmap[word])); 2233 2234 word += 1; 2235 } else { 2236 /* one or more dmap words are fully contained 2237 * within the block range. determine how many 2238 * words and allocate (set to 1) the bits of these 2239 * words. 2240 */ 2241 nwords = rembits >> L2DBWORD; 2242 memset(&dp->wmap[word], (int) ONES, nwords * 4); 2243 2244 /* determine how many bits. 2245 */ 2246 nb = nwords << L2DBWORD; 2247 2248 /* now update the appropriate leaves to reflect 2249 * the allocated words. 2250 */ 2251 for (; nwords > 0; nwords -= nw) { 2252 if (leaf[word] < BUDMIN) { 2253 jfs_error(bmp->db_ipbmap->i_sb, 2254 "leaf page corrupt\n"); 2255 break; 2256 } 2257 2258 /* determine what the leaf value should be 2259 * updated to as the minimum of the l2 number 2260 * of bits being allocated and the l2 number 2261 * of bits currently described by this leaf. 2262 */ 2263 size = min((int)leaf[word], NLSTOL2BSZ(nwords)); 2264 2265 /* update the leaf to reflect the allocation. 2266 * in addition to setting the leaf value to 2267 * NOFREE, dbSplit() will split the binary 2268 * system of the leaves to reflect the current 2269 * allocation (size). 2270 */ 2271 dbSplit(tp, word, size, NOFREE); 2272 2273 /* get the number of dmap words handled */ 2274 nw = BUDSIZE(size, BUDMIN); 2275 word += nw; 2276 } 2277 } 2278 } 2279 2280 /* update the free count for this dmap */ 2281 le32_add_cpu(&dp->nfree, -nblocks); 2282 2283 BMAP_LOCK(bmp); 2284 2285 /* if this allocation group is completely free, 2286 * update the maximum allocation group number if this allocation 2287 * group is the new max. 2288 */ 2289 agno = blkno >> bmp->db_agl2size; 2290 if (agno > bmp->db_maxag) 2291 bmp->db_maxag = agno; 2292 2293 /* update the free count for the allocation group and map */ 2294 bmp->db_agfree[agno] -= nblocks; 2295 bmp->db_nfree -= nblocks; 2296 2297 BMAP_UNLOCK(bmp); 2298 } 2299 2300 2301 /* 2302 * NAME: dbFreeBits() 2303 * 2304 * FUNCTION: free a specified block range from a dmap. 2305 * 2306 * this routine updates the dmap to reflect the working 2307 * state allocation of the specified block range. it directly 2308 * updates the bits of the working map and causes the adjustment 2309 * of the binary buddy system described by the dmap's dmtree 2310 * leaves to reflect the bits freed. it also causes the dmap's 2311 * dmtree, as a whole, to reflect the deallocated range. 2312 * 2313 * PARAMETERS: 2314 * bmp - pointer to bmap descriptor 2315 * dp - pointer to dmap to free bits from. 2316 * blkno - starting block number of the bits to be freed. 2317 * nblocks - number of bits to be freed. 2318 * 2319 * RETURN VALUES: 0 for success 2320 * 2321 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2322 */ 2323 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2324 int nblocks) 2325 { 2326 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2327 dmtree_t *tp = (dmtree_t *) & dp->tree; 2328 int rc = 0; 2329 int size; 2330 2331 /* determine the bit number and word within the dmap of the 2332 * starting block. 2333 */ 2334 dbitno = blkno & (BPERDMAP - 1); 2335 word = dbitno >> L2DBWORD; 2336 2337 /* block range better be within the dmap. 2338 */ 2339 assert(dbitno + nblocks <= BPERDMAP); 2340 2341 /* free the bits of the dmaps words corresponding to the block range. 2342 * not all bits of the first and last words may be contained within 2343 * the block range. if this is the case, we'll work against those 2344 * words (i.e. partial first and/or last) on an individual basis 2345 * (a single pass), freeing the bits of interest by hand and updating 2346 * the leaf corresponding to the dmap word. a single pass will be used 2347 * for all dmap words fully contained within the specified range. 2348 * within this pass, the bits of all fully contained dmap words will 2349 * be marked as free in a single shot and the leaves will be updated. a 2350 * single leaf may describe the free space of multiple dmap words, 2351 * so we may update only a subset of the actual leaves corresponding 2352 * to the dmap words of the block range. 2353 * 2354 * dbJoin() is used to update leaf values and will join the binary 2355 * buddy system of the leaves if the new leaf values indicate this 2356 * should be done. 2357 */ 2358 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2359 /* determine the bit number within the word and 2360 * the number of bits within the word. 2361 */ 2362 wbitno = dbitno & (DBWORD - 1); 2363 nb = min(rembits, DBWORD - wbitno); 2364 2365 /* check if only part of a word is to be freed. 2366 */ 2367 if (nb < DBWORD) { 2368 /* free (zero) the appropriate bits within this 2369 * dmap word. 2370 */ 2371 dp->wmap[word] &= 2372 cpu_to_le32(~(ONES << (DBWORD - nb) 2373 >> wbitno)); 2374 2375 /* update the leaf for this dmap word. 2376 */ 2377 rc = dbJoin(tp, word, 2378 dbMaxBud((u8 *) & dp->wmap[word])); 2379 if (rc) 2380 return rc; 2381 2382 word += 1; 2383 } else { 2384 /* one or more dmap words are fully contained 2385 * within the block range. determine how many 2386 * words and free (zero) the bits of these words. 2387 */ 2388 nwords = rembits >> L2DBWORD; 2389 memset(&dp->wmap[word], 0, nwords * 4); 2390 2391 /* determine how many bits. 2392 */ 2393 nb = nwords << L2DBWORD; 2394 2395 /* now update the appropriate leaves to reflect 2396 * the freed words. 2397 */ 2398 for (; nwords > 0; nwords -= nw) { 2399 /* determine what the leaf value should be 2400 * updated to as the minimum of the l2 number 2401 * of bits being freed and the l2 (max) number 2402 * of bits that can be described by this leaf. 2403 */ 2404 size = 2405 min(LITOL2BSZ 2406 (word, L2LPERDMAP, BUDMIN), 2407 NLSTOL2BSZ(nwords)); 2408 2409 /* update the leaf. 2410 */ 2411 rc = dbJoin(tp, word, size); 2412 if (rc) 2413 return rc; 2414 2415 /* get the number of dmap words handled. 2416 */ 2417 nw = BUDSIZE(size, BUDMIN); 2418 word += nw; 2419 } 2420 } 2421 } 2422 2423 /* update the free count for this dmap. 2424 */ 2425 le32_add_cpu(&dp->nfree, nblocks); 2426 2427 BMAP_LOCK(bmp); 2428 2429 /* update the free count for the allocation group and 2430 * map. 2431 */ 2432 agno = blkno >> bmp->db_agl2size; 2433 bmp->db_nfree += nblocks; 2434 bmp->db_agfree[agno] += nblocks; 2435 2436 /* check if this allocation group is not completely free and 2437 * if it is currently the maximum (rightmost) allocation group. 2438 * if so, establish the new maximum allocation group number by 2439 * searching left for the first allocation group with allocation. 2440 */ 2441 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) || 2442 (agno == bmp->db_numag - 1 && 2443 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) { 2444 while (bmp->db_maxag > 0) { 2445 bmp->db_maxag -= 1; 2446 if (bmp->db_agfree[bmp->db_maxag] != 2447 bmp->db_agsize) 2448 break; 2449 } 2450 2451 /* re-establish the allocation group preference if the 2452 * current preference is right of the maximum allocation 2453 * group. 2454 */ 2455 if (bmp->db_agpref > bmp->db_maxag) 2456 bmp->db_agpref = bmp->db_maxag; 2457 } 2458 2459 BMAP_UNLOCK(bmp); 2460 2461 return 0; 2462 } 2463 2464 2465 /* 2466 * NAME: dbAdjCtl() 2467 * 2468 * FUNCTION: adjust a dmap control page at a specified level to reflect 2469 * the change in a lower level dmap or dmap control page's 2470 * maximum string of free blocks (i.e. a change in the root 2471 * of the lower level object's dmtree) due to the allocation 2472 * or deallocation of a range of blocks with a single dmap. 2473 * 2474 * on entry, this routine is provided with the new value of 2475 * the lower level dmap or dmap control page root and the 2476 * starting block number of the block range whose allocation 2477 * or deallocation resulted in the root change. this range 2478 * is respresented by a single leaf of the current dmapctl 2479 * and the leaf will be updated with this value, possibly 2480 * causing a binary buddy system within the leaves to be 2481 * split or joined. the update may also cause the dmapctl's 2482 * dmtree to be updated. 2483 * 2484 * if the adjustment of the dmap control page, itself, causes its 2485 * root to change, this change will be bubbled up to the next dmap 2486 * control level by a recursive call to this routine, specifying 2487 * the new root value and the next dmap control page level to 2488 * be adjusted. 2489 * PARAMETERS: 2490 * bmp - pointer to bmap descriptor 2491 * blkno - the first block of a block range within a dmap. it is 2492 * the allocation or deallocation of this block range that 2493 * requires the dmap control page to be adjusted. 2494 * newval - the new value of the lower level dmap or dmap control 2495 * page root. 2496 * alloc - 'true' if adjustment is due to an allocation. 2497 * level - current level of dmap control page (i.e. L0, L1, L2) to 2498 * be adjusted. 2499 * 2500 * RETURN VALUES: 2501 * 0 - success 2502 * -EIO - i/o error 2503 * 2504 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2505 */ 2506 static int 2507 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level) 2508 { 2509 struct metapage *mp; 2510 s8 oldroot; 2511 int oldval; 2512 s64 lblkno; 2513 struct dmapctl *dcp; 2514 int rc, leafno, ti; 2515 2516 /* get the buffer for the dmap control page for the specified 2517 * block number and control page level. 2518 */ 2519 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level); 2520 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 2521 if (mp == NULL) 2522 return -EIO; 2523 dcp = (struct dmapctl *) mp->data; 2524 2525 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 2526 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 2527 release_metapage(mp); 2528 return -EIO; 2529 } 2530 2531 /* determine the leaf number corresponding to the block and 2532 * the index within the dmap control tree. 2533 */ 2534 leafno = BLKTOCTLLEAF(blkno, dcp->budmin); 2535 ti = leafno + le32_to_cpu(dcp->leafidx); 2536 2537 /* save the current leaf value and the current root level (i.e. 2538 * maximum l2 free string described by this dmapctl). 2539 */ 2540 oldval = dcp->stree[ti]; 2541 oldroot = dcp->stree[ROOT]; 2542 2543 /* check if this is a control page update for an allocation. 2544 * if so, update the leaf to reflect the new leaf value using 2545 * dbSplit(); otherwise (deallocation), use dbJoin() to update 2546 * the leaf with the new value. in addition to updating the 2547 * leaf, dbSplit() will also split the binary buddy system of 2548 * the leaves, if required, and bubble new values within the 2549 * dmapctl tree, if required. similarly, dbJoin() will join 2550 * the binary buddy system of leaves and bubble new values up 2551 * the dmapctl tree as required by the new leaf value. 2552 */ 2553 if (alloc) { 2554 /* check if we are in the middle of a binary buddy 2555 * system. this happens when we are performing the 2556 * first allocation out of an allocation group that 2557 * is part (not the first part) of a larger binary 2558 * buddy system. if we are in the middle, back split 2559 * the system prior to calling dbSplit() which assumes 2560 * that it is at the front of a binary buddy system. 2561 */ 2562 if (oldval == NOFREE) { 2563 rc = dbBackSplit((dmtree_t *) dcp, leafno); 2564 if (rc) 2565 return rc; 2566 oldval = dcp->stree[ti]; 2567 } 2568 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval); 2569 } else { 2570 rc = dbJoin((dmtree_t *) dcp, leafno, newval); 2571 if (rc) 2572 return rc; 2573 } 2574 2575 /* check if the root of the current dmap control page changed due 2576 * to the update and if the current dmap control page is not at 2577 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e. 2578 * root changed and this is not the top level), call this routine 2579 * again (recursion) for the next higher level of the mapping to 2580 * reflect the change in root for the current dmap control page. 2581 */ 2582 if (dcp->stree[ROOT] != oldroot) { 2583 /* are we below the top level of the map. if so, 2584 * bubble the root up to the next higher level. 2585 */ 2586 if (level < bmp->db_maxlevel) { 2587 /* bubble up the new root of this dmap control page to 2588 * the next level. 2589 */ 2590 if ((rc = 2591 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc, 2592 level + 1))) { 2593 /* something went wrong in bubbling up the new 2594 * root value, so backout the changes to the 2595 * current dmap control page. 2596 */ 2597 if (alloc) { 2598 dbJoin((dmtree_t *) dcp, leafno, 2599 oldval); 2600 } else { 2601 /* the dbJoin() above might have 2602 * caused a larger binary buddy system 2603 * to form and we may now be in the 2604 * middle of it. if this is the case, 2605 * back split the buddies. 2606 */ 2607 if (dcp->stree[ti] == NOFREE) 2608 dbBackSplit((dmtree_t *) 2609 dcp, leafno); 2610 dbSplit((dmtree_t *) dcp, leafno, 2611 dcp->budmin, oldval); 2612 } 2613 2614 /* release the buffer and return the error. 2615 */ 2616 release_metapage(mp); 2617 return (rc); 2618 } 2619 } else { 2620 /* we're at the top level of the map. update 2621 * the bmap control page to reflect the size 2622 * of the maximum free buddy system. 2623 */ 2624 assert(level == bmp->db_maxlevel); 2625 if (bmp->db_maxfreebud != oldroot) { 2626 jfs_error(bmp->db_ipbmap->i_sb, 2627 "the maximum free buddy is not the old root\n"); 2628 } 2629 bmp->db_maxfreebud = dcp->stree[ROOT]; 2630 } 2631 } 2632 2633 /* write the buffer. 2634 */ 2635 write_metapage(mp); 2636 2637 return (0); 2638 } 2639 2640 2641 /* 2642 * NAME: dbSplit() 2643 * 2644 * FUNCTION: update the leaf of a dmtree with a new value, splitting 2645 * the leaf from the binary buddy system of the dmtree's 2646 * leaves, as required. 2647 * 2648 * PARAMETERS: 2649 * tp - pointer to the tree containing the leaf. 2650 * leafno - the number of the leaf to be updated. 2651 * splitsz - the size the binary buddy system starting at the leaf 2652 * must be split to, specified as the log2 number of blocks. 2653 * newval - the new value for the leaf. 2654 * 2655 * RETURN VALUES: none 2656 * 2657 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2658 */ 2659 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval) 2660 { 2661 int budsz; 2662 int cursz; 2663 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2664 2665 /* check if the leaf needs to be split. 2666 */ 2667 if (leaf[leafno] > tp->dmt_budmin) { 2668 /* the split occurs by cutting the buddy system in half 2669 * at the specified leaf until we reach the specified 2670 * size. pick up the starting split size (current size 2671 * - 1 in l2) and the corresponding buddy size. 2672 */ 2673 cursz = leaf[leafno] - 1; 2674 budsz = BUDSIZE(cursz, tp->dmt_budmin); 2675 2676 /* split until we reach the specified size. 2677 */ 2678 while (cursz >= splitsz) { 2679 /* update the buddy's leaf with its new value. 2680 */ 2681 dbAdjTree(tp, leafno ^ budsz, cursz); 2682 2683 /* on to the next size and buddy. 2684 */ 2685 cursz -= 1; 2686 budsz >>= 1; 2687 } 2688 } 2689 2690 /* adjust the dmap tree to reflect the specified leaf's new 2691 * value. 2692 */ 2693 dbAdjTree(tp, leafno, newval); 2694 } 2695 2696 2697 /* 2698 * NAME: dbBackSplit() 2699 * 2700 * FUNCTION: back split the binary buddy system of dmtree leaves 2701 * that hold a specified leaf until the specified leaf 2702 * starts its own binary buddy system. 2703 * 2704 * the allocators typically perform allocations at the start 2705 * of binary buddy systems and dbSplit() is used to accomplish 2706 * any required splits. in some cases, however, allocation 2707 * may occur in the middle of a binary system and requires a 2708 * back split, with the split proceeding out from the middle of 2709 * the system (less efficient) rather than the start of the 2710 * system (more efficient). the cases in which a back split 2711 * is required are rare and are limited to the first allocation 2712 * within an allocation group which is a part (not first part) 2713 * of a larger binary buddy system and a few exception cases 2714 * in which a previous join operation must be backed out. 2715 * 2716 * PARAMETERS: 2717 * tp - pointer to the tree containing the leaf. 2718 * leafno - the number of the leaf to be updated. 2719 * 2720 * RETURN VALUES: none 2721 * 2722 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2723 */ 2724 static int dbBackSplit(dmtree_t * tp, int leafno) 2725 { 2726 int budsz, bud, w, bsz, size; 2727 int cursz; 2728 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2729 2730 /* leaf should be part (not first part) of a binary 2731 * buddy system. 2732 */ 2733 assert(leaf[leafno] == NOFREE); 2734 2735 /* the back split is accomplished by iteratively finding the leaf 2736 * that starts the buddy system that contains the specified leaf and 2737 * splitting that system in two. this iteration continues until 2738 * the specified leaf becomes the start of a buddy system. 2739 * 2740 * determine maximum possible l2 size for the specified leaf. 2741 */ 2742 size = 2743 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs), 2744 tp->dmt_budmin); 2745 2746 /* determine the number of leaves covered by this size. this 2747 * is the buddy size that we will start with as we search for 2748 * the buddy system that contains the specified leaf. 2749 */ 2750 budsz = BUDSIZE(size, tp->dmt_budmin); 2751 2752 /* back split. 2753 */ 2754 while (leaf[leafno] == NOFREE) { 2755 /* find the leftmost buddy leaf. 2756 */ 2757 for (w = leafno, bsz = budsz;; bsz <<= 1, 2758 w = (w < bud) ? w : bud) { 2759 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) { 2760 jfs_err("JFS: block map error in dbBackSplit"); 2761 return -EIO; 2762 } 2763 2764 /* determine the buddy. 2765 */ 2766 bud = w ^ bsz; 2767 2768 /* check if this buddy is the start of the system. 2769 */ 2770 if (leaf[bud] != NOFREE) { 2771 /* split the leaf at the start of the 2772 * system in two. 2773 */ 2774 cursz = leaf[bud] - 1; 2775 dbSplit(tp, bud, cursz, cursz); 2776 break; 2777 } 2778 } 2779 } 2780 2781 if (leaf[leafno] != size) { 2782 jfs_err("JFS: wrong leaf value in dbBackSplit"); 2783 return -EIO; 2784 } 2785 return 0; 2786 } 2787 2788 2789 /* 2790 * NAME: dbJoin() 2791 * 2792 * FUNCTION: update the leaf of a dmtree with a new value, joining 2793 * the leaf with other leaves of the dmtree into a multi-leaf 2794 * binary buddy system, as required. 2795 * 2796 * PARAMETERS: 2797 * tp - pointer to the tree containing the leaf. 2798 * leafno - the number of the leaf to be updated. 2799 * newval - the new value for the leaf. 2800 * 2801 * RETURN VALUES: none 2802 */ 2803 static int dbJoin(dmtree_t * tp, int leafno, int newval) 2804 { 2805 int budsz, buddy; 2806 s8 *leaf; 2807 2808 /* can the new leaf value require a join with other leaves ? 2809 */ 2810 if (newval >= tp->dmt_budmin) { 2811 /* pickup a pointer to the leaves of the tree. 2812 */ 2813 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2814 2815 /* try to join the specified leaf into a large binary 2816 * buddy system. the join proceeds by attempting to join 2817 * the specified leafno with its buddy (leaf) at new value. 2818 * if the join occurs, we attempt to join the left leaf 2819 * of the joined buddies with its buddy at new value + 1. 2820 * we continue to join until we find a buddy that cannot be 2821 * joined (does not have a value equal to the size of the 2822 * last join) or until all leaves have been joined into a 2823 * single system. 2824 * 2825 * get the buddy size (number of words covered) of 2826 * the new value. 2827 */ 2828 budsz = BUDSIZE(newval, tp->dmt_budmin); 2829 2830 /* try to join. 2831 */ 2832 while (budsz < le32_to_cpu(tp->dmt_nleafs)) { 2833 /* get the buddy leaf. 2834 */ 2835 buddy = leafno ^ budsz; 2836 2837 /* if the leaf's new value is greater than its 2838 * buddy's value, we join no more. 2839 */ 2840 if (newval > leaf[buddy]) 2841 break; 2842 2843 /* It shouldn't be less */ 2844 if (newval < leaf[buddy]) 2845 return -EIO; 2846 2847 /* check which (leafno or buddy) is the left buddy. 2848 * the left buddy gets to claim the blocks resulting 2849 * from the join while the right gets to claim none. 2850 * the left buddy is also eligible to participate in 2851 * a join at the next higher level while the right 2852 * is not. 2853 * 2854 */ 2855 if (leafno < buddy) { 2856 /* leafno is the left buddy. 2857 */ 2858 dbAdjTree(tp, buddy, NOFREE); 2859 } else { 2860 /* buddy is the left buddy and becomes 2861 * leafno. 2862 */ 2863 dbAdjTree(tp, leafno, NOFREE); 2864 leafno = buddy; 2865 } 2866 2867 /* on to try the next join. 2868 */ 2869 newval += 1; 2870 budsz <<= 1; 2871 } 2872 } 2873 2874 /* update the leaf value. 2875 */ 2876 dbAdjTree(tp, leafno, newval); 2877 2878 return 0; 2879 } 2880 2881 2882 /* 2883 * NAME: dbAdjTree() 2884 * 2885 * FUNCTION: update a leaf of a dmtree with a new value, adjusting 2886 * the dmtree, as required, to reflect the new leaf value. 2887 * the combination of any buddies must already be done before 2888 * this is called. 2889 * 2890 * PARAMETERS: 2891 * tp - pointer to the tree to be adjusted. 2892 * leafno - the number of the leaf to be updated. 2893 * newval - the new value for the leaf. 2894 * 2895 * RETURN VALUES: none 2896 */ 2897 static void dbAdjTree(dmtree_t * tp, int leafno, int newval) 2898 { 2899 int lp, pp, k; 2900 int max; 2901 2902 /* pick up the index of the leaf for this leafno. 2903 */ 2904 lp = leafno + le32_to_cpu(tp->dmt_leafidx); 2905 2906 /* is the current value the same as the old value ? if so, 2907 * there is nothing to do. 2908 */ 2909 if (tp->dmt_stree[lp] == newval) 2910 return; 2911 2912 /* set the new value. 2913 */ 2914 tp->dmt_stree[lp] = newval; 2915 2916 /* bubble the new value up the tree as required. 2917 */ 2918 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) { 2919 /* get the index of the first leaf of the 4 leaf 2920 * group containing the specified leaf (leafno). 2921 */ 2922 lp = ((lp - 1) & ~0x03) + 1; 2923 2924 /* get the index of the parent of this 4 leaf group. 2925 */ 2926 pp = (lp - 1) >> 2; 2927 2928 /* determine the maximum of the 4 leaves. 2929 */ 2930 max = TREEMAX(&tp->dmt_stree[lp]); 2931 2932 /* if the maximum of the 4 is the same as the 2933 * parent's value, we're done. 2934 */ 2935 if (tp->dmt_stree[pp] == max) 2936 break; 2937 2938 /* parent gets new value. 2939 */ 2940 tp->dmt_stree[pp] = max; 2941 2942 /* parent becomes leaf for next go-round. 2943 */ 2944 lp = pp; 2945 } 2946 } 2947 2948 2949 /* 2950 * NAME: dbFindLeaf() 2951 * 2952 * FUNCTION: search a dmtree_t for sufficient free blocks, returning 2953 * the index of a leaf describing the free blocks if 2954 * sufficient free blocks are found. 2955 * 2956 * the search starts at the top of the dmtree_t tree and 2957 * proceeds down the tree to the leftmost leaf with sufficient 2958 * free space. 2959 * 2960 * PARAMETERS: 2961 * tp - pointer to the tree to be searched. 2962 * l2nb - log2 number of free blocks to search for. 2963 * leafidx - return pointer to be set to the index of the leaf 2964 * describing at least l2nb free blocks if sufficient 2965 * free blocks are found. 2966 * 2967 * RETURN VALUES: 2968 * 0 - success 2969 * -ENOSPC - insufficient free blocks. 2970 */ 2971 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx) 2972 { 2973 int ti, n = 0, k, x = 0; 2974 2975 /* first check the root of the tree to see if there is 2976 * sufficient free space. 2977 */ 2978 if (l2nb > tp->dmt_stree[ROOT]) 2979 return -ENOSPC; 2980 2981 /* sufficient free space available. now search down the tree 2982 * starting at the next level for the leftmost leaf that 2983 * describes sufficient free space. 2984 */ 2985 for (k = le32_to_cpu(tp->dmt_height), ti = 1; 2986 k > 0; k--, ti = ((ti + n) << 2) + 1) { 2987 /* search the four nodes at this level, starting from 2988 * the left. 2989 */ 2990 for (x = ti, n = 0; n < 4; n++) { 2991 /* sufficient free space found. move to the next 2992 * level (or quit if this is the last level). 2993 */ 2994 if (l2nb <= tp->dmt_stree[x + n]) 2995 break; 2996 } 2997 2998 /* better have found something since the higher 2999 * levels of the tree said it was here. 3000 */ 3001 assert(n < 4); 3002 } 3003 3004 /* set the return to the leftmost leaf describing sufficient 3005 * free space. 3006 */ 3007 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx); 3008 3009 return (0); 3010 } 3011 3012 3013 /* 3014 * NAME: dbFindBits() 3015 * 3016 * FUNCTION: find a specified number of binary buddy free bits within a 3017 * dmap bitmap word value. 3018 * 3019 * this routine searches the bitmap value for (1 << l2nb) free 3020 * bits at (1 << l2nb) alignments within the value. 3021 * 3022 * PARAMETERS: 3023 * word - dmap bitmap word value. 3024 * l2nb - number of free bits specified as a log2 number. 3025 * 3026 * RETURN VALUES: 3027 * starting bit number of free bits. 3028 */ 3029 static int dbFindBits(u32 word, int l2nb) 3030 { 3031 int bitno, nb; 3032 u32 mask; 3033 3034 /* get the number of bits. 3035 */ 3036 nb = 1 << l2nb; 3037 assert(nb <= DBWORD); 3038 3039 /* complement the word so we can use a mask (i.e. 0s represent 3040 * free bits) and compute the mask. 3041 */ 3042 word = ~word; 3043 mask = ONES << (DBWORD - nb); 3044 3045 /* scan the word for nb free bits at nb alignments. 3046 */ 3047 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) { 3048 if ((mask & word) == mask) 3049 break; 3050 } 3051 3052 ASSERT(bitno < 32); 3053 3054 /* return the bit number. 3055 */ 3056 return (bitno); 3057 } 3058 3059 3060 /* 3061 * NAME: dbMaxBud(u8 *cp) 3062 * 3063 * FUNCTION: determine the largest binary buddy string of free 3064 * bits within 32-bits of the map. 3065 * 3066 * PARAMETERS: 3067 * cp - pointer to the 32-bit value. 3068 * 3069 * RETURN VALUES: 3070 * largest binary buddy of free bits within a dmap word. 3071 */ 3072 static int dbMaxBud(u8 * cp) 3073 { 3074 signed char tmp1, tmp2; 3075 3076 /* check if the wmap word is all free. if so, the 3077 * free buddy size is BUDMIN. 3078 */ 3079 if (*((uint *) cp) == 0) 3080 return (BUDMIN); 3081 3082 /* check if the wmap word is half free. if so, the 3083 * free buddy size is BUDMIN-1. 3084 */ 3085 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0) 3086 return (BUDMIN - 1); 3087 3088 /* not all free or half free. determine the free buddy 3089 * size thru table lookup using quarters of the wmap word. 3090 */ 3091 tmp1 = max(budtab[cp[2]], budtab[cp[3]]); 3092 tmp2 = max(budtab[cp[0]], budtab[cp[1]]); 3093 return (max(tmp1, tmp2)); 3094 } 3095 3096 3097 /* 3098 * NAME: cnttz(uint word) 3099 * 3100 * FUNCTION: determine the number of trailing zeros within a 32-bit 3101 * value. 3102 * 3103 * PARAMETERS: 3104 * value - 32-bit value to be examined. 3105 * 3106 * RETURN VALUES: 3107 * count of trailing zeros 3108 */ 3109 static int cnttz(u32 word) 3110 { 3111 int n; 3112 3113 for (n = 0; n < 32; n++, word >>= 1) { 3114 if (word & 0x01) 3115 break; 3116 } 3117 3118 return (n); 3119 } 3120 3121 3122 /* 3123 * NAME: cntlz(u32 value) 3124 * 3125 * FUNCTION: determine the number of leading zeros within a 32-bit 3126 * value. 3127 * 3128 * PARAMETERS: 3129 * value - 32-bit value to be examined. 3130 * 3131 * RETURN VALUES: 3132 * count of leading zeros 3133 */ 3134 static int cntlz(u32 value) 3135 { 3136 int n; 3137 3138 for (n = 0; n < 32; n++, value <<= 1) { 3139 if (value & HIGHORDER) 3140 break; 3141 } 3142 return (n); 3143 } 3144 3145 3146 /* 3147 * NAME: blkstol2(s64 nb) 3148 * 3149 * FUNCTION: convert a block count to its log2 value. if the block 3150 * count is not a l2 multiple, it is rounded up to the next 3151 * larger l2 multiple. 3152 * 3153 * PARAMETERS: 3154 * nb - number of blocks 3155 * 3156 * RETURN VALUES: 3157 * log2 number of blocks 3158 */ 3159 static int blkstol2(s64 nb) 3160 { 3161 int l2nb; 3162 s64 mask; /* meant to be signed */ 3163 3164 mask = (s64) 1 << (64 - 1); 3165 3166 /* count the leading bits. 3167 */ 3168 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) { 3169 /* leading bit found. 3170 */ 3171 if (nb & mask) { 3172 /* determine the l2 value. 3173 */ 3174 l2nb = (64 - 1) - l2nb; 3175 3176 /* check if we need to round up. 3177 */ 3178 if (~mask & nb) 3179 l2nb++; 3180 3181 return (l2nb); 3182 } 3183 } 3184 assert(0); 3185 return 0; /* fix compiler warning */ 3186 } 3187 3188 3189 /* 3190 * NAME: dbAllocBottomUp() 3191 * 3192 * FUNCTION: alloc the specified block range from the working block 3193 * allocation map. 3194 * 3195 * the blocks will be alloc from the working map one dmap 3196 * at a time. 3197 * 3198 * PARAMETERS: 3199 * ip - pointer to in-core inode; 3200 * blkno - starting block number to be freed. 3201 * nblocks - number of blocks to be freed. 3202 * 3203 * RETURN VALUES: 3204 * 0 - success 3205 * -EIO - i/o error 3206 */ 3207 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks) 3208 { 3209 struct metapage *mp; 3210 struct dmap *dp; 3211 int nb, rc; 3212 s64 lblkno, rem; 3213 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 3214 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 3215 3216 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 3217 3218 /* block to be allocated better be within the mapsize. */ 3219 ASSERT(nblocks <= bmp->db_mapsize - blkno); 3220 3221 /* 3222 * allocate the blocks a dmap at a time. 3223 */ 3224 mp = NULL; 3225 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 3226 /* release previous dmap if any */ 3227 if (mp) { 3228 write_metapage(mp); 3229 } 3230 3231 /* get the buffer for the current dmap. */ 3232 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 3233 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 3234 if (mp == NULL) { 3235 IREAD_UNLOCK(ipbmap); 3236 return -EIO; 3237 } 3238 dp = (struct dmap *) mp->data; 3239 3240 /* determine the number of blocks to be allocated from 3241 * this dmap. 3242 */ 3243 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 3244 3245 /* allocate the blocks. */ 3246 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) { 3247 release_metapage(mp); 3248 IREAD_UNLOCK(ipbmap); 3249 return (rc); 3250 } 3251 } 3252 3253 /* write the last buffer. */ 3254 write_metapage(mp); 3255 3256 IREAD_UNLOCK(ipbmap); 3257 3258 return (0); 3259 } 3260 3261 3262 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 3263 int nblocks) 3264 { 3265 int rc; 3266 int dbitno, word, rembits, nb, nwords, wbitno, agno; 3267 s8 oldroot; 3268 struct dmaptree *tp = (struct dmaptree *) & dp->tree; 3269 3270 /* save the current value of the root (i.e. maximum free string) 3271 * of the dmap tree. 3272 */ 3273 oldroot = tp->stree[ROOT]; 3274 3275 /* determine the bit number and word within the dmap of the 3276 * starting block. 3277 */ 3278 dbitno = blkno & (BPERDMAP - 1); 3279 word = dbitno >> L2DBWORD; 3280 3281 /* block range better be within the dmap */ 3282 assert(dbitno + nblocks <= BPERDMAP); 3283 3284 /* allocate the bits of the dmap's words corresponding to the block 3285 * range. not all bits of the first and last words may be contained 3286 * within the block range. if this is the case, we'll work against 3287 * those words (i.e. partial first and/or last) on an individual basis 3288 * (a single pass), allocating the bits of interest by hand and 3289 * updating the leaf corresponding to the dmap word. a single pass 3290 * will be used for all dmap words fully contained within the 3291 * specified range. within this pass, the bits of all fully contained 3292 * dmap words will be marked as free in a single shot and the leaves 3293 * will be updated. a single leaf may describe the free space of 3294 * multiple dmap words, so we may update only a subset of the actual 3295 * leaves corresponding to the dmap words of the block range. 3296 */ 3297 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 3298 /* determine the bit number within the word and 3299 * the number of bits within the word. 3300 */ 3301 wbitno = dbitno & (DBWORD - 1); 3302 nb = min(rembits, DBWORD - wbitno); 3303 3304 /* check if only part of a word is to be allocated. 3305 */ 3306 if (nb < DBWORD) { 3307 /* allocate (set to 1) the appropriate bits within 3308 * this dmap word. 3309 */ 3310 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 3311 >> wbitno); 3312 3313 word++; 3314 } else { 3315 /* one or more dmap words are fully contained 3316 * within the block range. determine how many 3317 * words and allocate (set to 1) the bits of these 3318 * words. 3319 */ 3320 nwords = rembits >> L2DBWORD; 3321 memset(&dp->wmap[word], (int) ONES, nwords * 4); 3322 3323 /* determine how many bits */ 3324 nb = nwords << L2DBWORD; 3325 word += nwords; 3326 } 3327 } 3328 3329 /* update the free count for this dmap */ 3330 le32_add_cpu(&dp->nfree, -nblocks); 3331 3332 /* reconstruct summary tree */ 3333 dbInitDmapTree(dp); 3334 3335 BMAP_LOCK(bmp); 3336 3337 /* if this allocation group is completely free, 3338 * update the highest active allocation group number 3339 * if this allocation group is the new max. 3340 */ 3341 agno = blkno >> bmp->db_agl2size; 3342 if (agno > bmp->db_maxag) 3343 bmp->db_maxag = agno; 3344 3345 /* update the free count for the allocation group and map */ 3346 bmp->db_agfree[agno] -= nblocks; 3347 bmp->db_nfree -= nblocks; 3348 3349 BMAP_UNLOCK(bmp); 3350 3351 /* if the root has not changed, done. */ 3352 if (tp->stree[ROOT] == oldroot) 3353 return (0); 3354 3355 /* root changed. bubble the change up to the dmap control pages. 3356 * if the adjustment of the upper level control pages fails, 3357 * backout the bit allocation (thus making everything consistent). 3358 */ 3359 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0))) 3360 dbFreeBits(bmp, dp, blkno, nblocks); 3361 3362 return (rc); 3363 } 3364 3365 3366 /* 3367 * NAME: dbExtendFS() 3368 * 3369 * FUNCTION: extend bmap from blkno for nblocks; 3370 * dbExtendFS() updates bmap ready for dbAllocBottomUp(); 3371 * 3372 * L2 3373 * | 3374 * L1---------------------------------L1 3375 * | | 3376 * L0---------L0---------L0 L0---------L0---------L0 3377 * | | | | | | 3378 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm; 3379 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm 3380 * 3381 * <---old---><----------------------------extend-----------------------> 3382 */ 3383 int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks) 3384 { 3385 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb); 3386 int nbperpage = sbi->nbperpage; 3387 int i, i0 = true, j, j0 = true, k, n; 3388 s64 newsize; 3389 s64 p; 3390 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL; 3391 struct dmapctl *l2dcp, *l1dcp, *l0dcp; 3392 struct dmap *dp; 3393 s8 *l0leaf, *l1leaf, *l2leaf; 3394 struct bmap *bmp = sbi->bmap; 3395 int agno, l2agsize, oldl2agsize; 3396 s64 ag_rem; 3397 3398 newsize = blkno + nblocks; 3399 3400 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld", 3401 (long long) blkno, (long long) nblocks, (long long) newsize); 3402 3403 /* 3404 * initialize bmap control page. 3405 * 3406 * all the data in bmap control page should exclude 3407 * the mkfs hidden dmap page. 3408 */ 3409 3410 /* update mapsize */ 3411 bmp->db_mapsize = newsize; 3412 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize); 3413 3414 /* compute new AG size */ 3415 l2agsize = dbGetL2AGSize(newsize); 3416 oldl2agsize = bmp->db_agl2size; 3417 3418 bmp->db_agl2size = l2agsize; 3419 bmp->db_agsize = 1 << l2agsize; 3420 3421 /* compute new number of AG */ 3422 agno = bmp->db_numag; 3423 bmp->db_numag = newsize >> l2agsize; 3424 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0; 3425 3426 /* 3427 * reconfigure db_agfree[] 3428 * from old AG configuration to new AG configuration; 3429 * 3430 * coalesce contiguous k (newAGSize/oldAGSize) AGs; 3431 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn; 3432 * note: new AG size = old AG size * (2**x). 3433 */ 3434 if (l2agsize == oldl2agsize) 3435 goto extend; 3436 k = 1 << (l2agsize - oldl2agsize); 3437 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */ 3438 for (i = 0, n = 0; i < agno; n++) { 3439 bmp->db_agfree[n] = 0; /* init collection point */ 3440 3441 /* coalesce contiguous k AGs; */ 3442 for (j = 0; j < k && i < agno; j++, i++) { 3443 /* merge AGi to AGn */ 3444 bmp->db_agfree[n] += bmp->db_agfree[i]; 3445 } 3446 } 3447 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */ 3448 3449 for (; n < MAXAG; n++) 3450 bmp->db_agfree[n] = 0; 3451 3452 /* 3453 * update highest active ag number 3454 */ 3455 3456 bmp->db_maxag = bmp->db_maxag / k; 3457 3458 /* 3459 * extend bmap 3460 * 3461 * update bit maps and corresponding level control pages; 3462 * global control page db_nfree, db_agfree[agno], db_maxfreebud; 3463 */ 3464 extend: 3465 /* get L2 page */ 3466 p = BMAPBLKNO + nbperpage; /* L2 page */ 3467 l2mp = read_metapage(ipbmap, p, PSIZE, 0); 3468 if (!l2mp) { 3469 jfs_error(ipbmap->i_sb, "L2 page could not be read\n"); 3470 return -EIO; 3471 } 3472 l2dcp = (struct dmapctl *) l2mp->data; 3473 3474 /* compute start L1 */ 3475 k = blkno >> L2MAXL1SIZE; 3476 l2leaf = l2dcp->stree + CTLLEAFIND + k; 3477 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */ 3478 3479 /* 3480 * extend each L1 in L2 3481 */ 3482 for (; k < LPERCTL; k++, p += nbperpage) { 3483 /* get L1 page */ 3484 if (j0) { 3485 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */ 3486 l1mp = read_metapage(ipbmap, p, PSIZE, 0); 3487 if (l1mp == NULL) 3488 goto errout; 3489 l1dcp = (struct dmapctl *) l1mp->data; 3490 3491 /* compute start L0 */ 3492 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE; 3493 l1leaf = l1dcp->stree + CTLLEAFIND + j; 3494 p = BLKTOL0(blkno, sbi->l2nbperpage); 3495 j0 = false; 3496 } else { 3497 /* assign/init L1 page */ 3498 l1mp = get_metapage(ipbmap, p, PSIZE, 0); 3499 if (l1mp == NULL) 3500 goto errout; 3501 3502 l1dcp = (struct dmapctl *) l1mp->data; 3503 3504 /* compute start L0 */ 3505 j = 0; 3506 l1leaf = l1dcp->stree + CTLLEAFIND; 3507 p += nbperpage; /* 1st L0 of L1.k */ 3508 } 3509 3510 /* 3511 * extend each L0 in L1 3512 */ 3513 for (; j < LPERCTL; j++) { 3514 /* get L0 page */ 3515 if (i0) { 3516 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */ 3517 3518 l0mp = read_metapage(ipbmap, p, PSIZE, 0); 3519 if (l0mp == NULL) 3520 goto errout; 3521 l0dcp = (struct dmapctl *) l0mp->data; 3522 3523 /* compute start dmap */ 3524 i = (blkno & (MAXL0SIZE - 1)) >> 3525 L2BPERDMAP; 3526 l0leaf = l0dcp->stree + CTLLEAFIND + i; 3527 p = BLKTODMAP(blkno, 3528 sbi->l2nbperpage); 3529 i0 = false; 3530 } else { 3531 /* assign/init L0 page */ 3532 l0mp = get_metapage(ipbmap, p, PSIZE, 0); 3533 if (l0mp == NULL) 3534 goto errout; 3535 3536 l0dcp = (struct dmapctl *) l0mp->data; 3537 3538 /* compute start dmap */ 3539 i = 0; 3540 l0leaf = l0dcp->stree + CTLLEAFIND; 3541 p += nbperpage; /* 1st dmap of L0.j */ 3542 } 3543 3544 /* 3545 * extend each dmap in L0 3546 */ 3547 for (; i < LPERCTL; i++) { 3548 /* 3549 * reconstruct the dmap page, and 3550 * initialize corresponding parent L0 leaf 3551 */ 3552 if ((n = blkno & (BPERDMAP - 1))) { 3553 /* read in dmap page: */ 3554 mp = read_metapage(ipbmap, p, 3555 PSIZE, 0); 3556 if (mp == NULL) 3557 goto errout; 3558 n = min(nblocks, (s64)BPERDMAP - n); 3559 } else { 3560 /* assign/init dmap page */ 3561 mp = read_metapage(ipbmap, p, 3562 PSIZE, 0); 3563 if (mp == NULL) 3564 goto errout; 3565 3566 n = min(nblocks, (s64)BPERDMAP); 3567 } 3568 3569 dp = (struct dmap *) mp->data; 3570 *l0leaf = dbInitDmap(dp, blkno, n); 3571 3572 bmp->db_nfree += n; 3573 agno = le64_to_cpu(dp->start) >> l2agsize; 3574 bmp->db_agfree[agno] += n; 3575 3576 write_metapage(mp); 3577 3578 l0leaf++; 3579 p += nbperpage; 3580 3581 blkno += n; 3582 nblocks -= n; 3583 if (nblocks == 0) 3584 break; 3585 } /* for each dmap in a L0 */ 3586 3587 /* 3588 * build current L0 page from its leaves, and 3589 * initialize corresponding parent L1 leaf 3590 */ 3591 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i); 3592 write_metapage(l0mp); 3593 l0mp = NULL; 3594 3595 if (nblocks) 3596 l1leaf++; /* continue for next L0 */ 3597 else { 3598 /* more than 1 L0 ? */ 3599 if (j > 0) 3600 break; /* build L1 page */ 3601 else { 3602 /* summarize in global bmap page */ 3603 bmp->db_maxfreebud = *l1leaf; 3604 release_metapage(l1mp); 3605 release_metapage(l2mp); 3606 goto finalize; 3607 } 3608 } 3609 } /* for each L0 in a L1 */ 3610 3611 /* 3612 * build current L1 page from its leaves, and 3613 * initialize corresponding parent L2 leaf 3614 */ 3615 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j); 3616 write_metapage(l1mp); 3617 l1mp = NULL; 3618 3619 if (nblocks) 3620 l2leaf++; /* continue for next L1 */ 3621 else { 3622 /* more than 1 L1 ? */ 3623 if (k > 0) 3624 break; /* build L2 page */ 3625 else { 3626 /* summarize in global bmap page */ 3627 bmp->db_maxfreebud = *l2leaf; 3628 release_metapage(l2mp); 3629 goto finalize; 3630 } 3631 } 3632 } /* for each L1 in a L2 */ 3633 3634 jfs_error(ipbmap->i_sb, "function has not returned as expected\n"); 3635 errout: 3636 if (l0mp) 3637 release_metapage(l0mp); 3638 if (l1mp) 3639 release_metapage(l1mp); 3640 release_metapage(l2mp); 3641 return -EIO; 3642 3643 /* 3644 * finalize bmap control page 3645 */ 3646 finalize: 3647 3648 return 0; 3649 } 3650 3651 3652 /* 3653 * dbFinalizeBmap() 3654 */ 3655 void dbFinalizeBmap(struct inode *ipbmap) 3656 { 3657 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 3658 int actags, inactags, l2nl; 3659 s64 ag_rem, actfree, inactfree, avgfree; 3660 int i, n; 3661 3662 /* 3663 * finalize bmap control page 3664 */ 3665 //finalize: 3666 /* 3667 * compute db_agpref: preferred ag to allocate from 3668 * (the leftmost ag with average free space in it); 3669 */ 3670 //agpref: 3671 /* get the number of active ags and inacitve ags */ 3672 actags = bmp->db_maxag + 1; 3673 inactags = bmp->db_numag - actags; 3674 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */ 3675 3676 /* determine how many blocks are in the inactive allocation 3677 * groups. in doing this, we must account for the fact that 3678 * the rightmost group might be a partial group (i.e. file 3679 * system size is not a multiple of the group size). 3680 */ 3681 inactfree = (inactags && ag_rem) ? 3682 ((inactags - 1) << bmp->db_agl2size) + ag_rem 3683 : inactags << bmp->db_agl2size; 3684 3685 /* determine how many free blocks are in the active 3686 * allocation groups plus the average number of free blocks 3687 * within the active ags. 3688 */ 3689 actfree = bmp->db_nfree - inactfree; 3690 avgfree = (u32) actfree / (u32) actags; 3691 3692 /* if the preferred allocation group has not average free space. 3693 * re-establish the preferred group as the leftmost 3694 * group with average free space. 3695 */ 3696 if (bmp->db_agfree[bmp->db_agpref] < avgfree) { 3697 for (bmp->db_agpref = 0; bmp->db_agpref < actags; 3698 bmp->db_agpref++) { 3699 if (bmp->db_agfree[bmp->db_agpref] >= avgfree) 3700 break; 3701 } 3702 if (bmp->db_agpref >= bmp->db_numag) { 3703 jfs_error(ipbmap->i_sb, 3704 "cannot find ag with average freespace\n"); 3705 } 3706 } 3707 3708 /* 3709 * compute db_aglevel, db_agheight, db_width, db_agstart: 3710 * an ag is covered in aglevel dmapctl summary tree, 3711 * at agheight level height (from leaf) with agwidth number of nodes 3712 * each, which starts at agstart index node of the smmary tree node 3713 * array; 3714 */ 3715 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize); 3716 l2nl = 3717 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL); 3718 bmp->db_agheight = l2nl >> 1; 3719 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1)); 3720 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0; 3721 i--) { 3722 bmp->db_agstart += n; 3723 n <<= 2; 3724 } 3725 3726 } 3727 3728 3729 /* 3730 * NAME: dbInitDmap()/ujfs_idmap_page() 3731 * 3732 * FUNCTION: initialize working/persistent bitmap of the dmap page 3733 * for the specified number of blocks: 3734 * 3735 * at entry, the bitmaps had been initialized as free (ZEROS); 3736 * The number of blocks will only account for the actually 3737 * existing blocks. Blocks which don't actually exist in 3738 * the aggregate will be marked as allocated (ONES); 3739 * 3740 * PARAMETERS: 3741 * dp - pointer to page of map 3742 * nblocks - number of blocks this page 3743 * 3744 * RETURNS: NONE 3745 */ 3746 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks) 3747 { 3748 int blkno, w, b, r, nw, nb, i; 3749 3750 /* starting block number within the dmap */ 3751 blkno = Blkno & (BPERDMAP - 1); 3752 3753 if (blkno == 0) { 3754 dp->nblocks = dp->nfree = cpu_to_le32(nblocks); 3755 dp->start = cpu_to_le64(Blkno); 3756 3757 if (nblocks == BPERDMAP) { 3758 memset(&dp->wmap[0], 0, LPERDMAP * 4); 3759 memset(&dp->pmap[0], 0, LPERDMAP * 4); 3760 goto initTree; 3761 } 3762 } else { 3763 le32_add_cpu(&dp->nblocks, nblocks); 3764 le32_add_cpu(&dp->nfree, nblocks); 3765 } 3766 3767 /* word number containing start block number */ 3768 w = blkno >> L2DBWORD; 3769 3770 /* 3771 * free the bits corresponding to the block range (ZEROS): 3772 * note: not all bits of the first and last words may be contained 3773 * within the block range. 3774 */ 3775 for (r = nblocks; r > 0; r -= nb, blkno += nb) { 3776 /* number of bits preceding range to be freed in the word */ 3777 b = blkno & (DBWORD - 1); 3778 /* number of bits to free in the word */ 3779 nb = min(r, DBWORD - b); 3780 3781 /* is partial word to be freed ? */ 3782 if (nb < DBWORD) { 3783 /* free (set to 0) from the bitmap word */ 3784 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3785 >> b)); 3786 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3787 >> b)); 3788 3789 /* skip the word freed */ 3790 w++; 3791 } else { 3792 /* free (set to 0) contiguous bitmap words */ 3793 nw = r >> L2DBWORD; 3794 memset(&dp->wmap[w], 0, nw * 4); 3795 memset(&dp->pmap[w], 0, nw * 4); 3796 3797 /* skip the words freed */ 3798 nb = nw << L2DBWORD; 3799 w += nw; 3800 } 3801 } 3802 3803 /* 3804 * mark bits following the range to be freed (non-existing 3805 * blocks) as allocated (ONES) 3806 */ 3807 3808 if (blkno == BPERDMAP) 3809 goto initTree; 3810 3811 /* the first word beyond the end of existing blocks */ 3812 w = blkno >> L2DBWORD; 3813 3814 /* does nblocks fall on a 32-bit boundary ? */ 3815 b = blkno & (DBWORD - 1); 3816 if (b) { 3817 /* mark a partial word allocated */ 3818 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b); 3819 w++; 3820 } 3821 3822 /* set the rest of the words in the page to allocated (ONES) */ 3823 for (i = w; i < LPERDMAP; i++) 3824 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES); 3825 3826 /* 3827 * init tree 3828 */ 3829 initTree: 3830 return (dbInitDmapTree(dp)); 3831 } 3832 3833 3834 /* 3835 * NAME: dbInitDmapTree()/ujfs_complete_dmap() 3836 * 3837 * FUNCTION: initialize summary tree of the specified dmap: 3838 * 3839 * at entry, bitmap of the dmap has been initialized; 3840 * 3841 * PARAMETERS: 3842 * dp - dmap to complete 3843 * blkno - starting block number for this dmap 3844 * treemax - will be filled in with max free for this dmap 3845 * 3846 * RETURNS: max free string at the root of the tree 3847 */ 3848 static int dbInitDmapTree(struct dmap * dp) 3849 { 3850 struct dmaptree *tp; 3851 s8 *cp; 3852 int i; 3853 3854 /* init fixed info of tree */ 3855 tp = &dp->tree; 3856 tp->nleafs = cpu_to_le32(LPERDMAP); 3857 tp->l2nleafs = cpu_to_le32(L2LPERDMAP); 3858 tp->leafidx = cpu_to_le32(LEAFIND); 3859 tp->height = cpu_to_le32(4); 3860 tp->budmin = BUDMIN; 3861 3862 /* init each leaf from corresponding wmap word: 3863 * note: leaf is set to NOFREE(-1) if all blocks of corresponding 3864 * bitmap word are allocated. 3865 */ 3866 cp = tp->stree + le32_to_cpu(tp->leafidx); 3867 for (i = 0; i < LPERDMAP; i++) 3868 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]); 3869 3870 /* build the dmap's binary buddy summary tree */ 3871 return (dbInitTree(tp)); 3872 } 3873 3874 3875 /* 3876 * NAME: dbInitTree()/ujfs_adjtree() 3877 * 3878 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl. 3879 * 3880 * at entry, the leaves of the tree has been initialized 3881 * from corresponding bitmap word or root of summary tree 3882 * of the child control page; 3883 * configure binary buddy system at the leaf level, then 3884 * bubble up the values of the leaf nodes up the tree. 3885 * 3886 * PARAMETERS: 3887 * cp - Pointer to the root of the tree 3888 * l2leaves- Number of leaf nodes as a power of 2 3889 * l2min - Number of blocks that can be covered by a leaf 3890 * as a power of 2 3891 * 3892 * RETURNS: max free string at the root of the tree 3893 */ 3894 static int dbInitTree(struct dmaptree * dtp) 3895 { 3896 int l2max, l2free, bsize, nextb, i; 3897 int child, parent, nparent; 3898 s8 *tp, *cp, *cp1; 3899 3900 tp = dtp->stree; 3901 3902 /* Determine the maximum free string possible for the leaves */ 3903 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin; 3904 3905 /* 3906 * configure the leaf levevl into binary buddy system 3907 * 3908 * Try to combine buddies starting with a buddy size of 1 3909 * (i.e. two leaves). At a buddy size of 1 two buddy leaves 3910 * can be combined if both buddies have a maximum free of l2min; 3911 * the combination will result in the left-most buddy leaf having 3912 * a maximum free of l2min+1. 3913 * After processing all buddies for a given size, process buddies 3914 * at the next higher buddy size (i.e. current size * 2) and 3915 * the next maximum free (current free + 1). 3916 * This continues until the maximum possible buddy combination 3917 * yields maximum free. 3918 */ 3919 for (l2free = dtp->budmin, bsize = 1; l2free < l2max; 3920 l2free++, bsize = nextb) { 3921 /* get next buddy size == current buddy pair size */ 3922 nextb = bsize << 1; 3923 3924 /* scan each adjacent buddy pair at current buddy size */ 3925 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx); 3926 i < le32_to_cpu(dtp->nleafs); 3927 i += nextb, cp += nextb) { 3928 /* coalesce if both adjacent buddies are max free */ 3929 if (*cp == l2free && *(cp + bsize) == l2free) { 3930 *cp = l2free + 1; /* left take right */ 3931 *(cp + bsize) = -1; /* right give left */ 3932 } 3933 } 3934 } 3935 3936 /* 3937 * bubble summary information of leaves up the tree. 3938 * 3939 * Starting at the leaf node level, the four nodes described by 3940 * the higher level parent node are compared for a maximum free and 3941 * this maximum becomes the value of the parent node. 3942 * when all lower level nodes are processed in this fashion then 3943 * move up to the next level (parent becomes a lower level node) and 3944 * continue the process for that level. 3945 */ 3946 for (child = le32_to_cpu(dtp->leafidx), 3947 nparent = le32_to_cpu(dtp->nleafs) >> 2; 3948 nparent > 0; nparent >>= 2, child = parent) { 3949 /* get index of 1st node of parent level */ 3950 parent = (child - 1) >> 2; 3951 3952 /* set the value of the parent node as the maximum 3953 * of the four nodes of the current level. 3954 */ 3955 for (i = 0, cp = tp + child, cp1 = tp + parent; 3956 i < nparent; i++, cp += 4, cp1++) 3957 *cp1 = TREEMAX(cp); 3958 } 3959 3960 return (*tp); 3961 } 3962 3963 3964 /* 3965 * dbInitDmapCtl() 3966 * 3967 * function: initialize dmapctl page 3968 */ 3969 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i) 3970 { /* start leaf index not covered by range */ 3971 s8 *cp; 3972 3973 dcp->nleafs = cpu_to_le32(LPERCTL); 3974 dcp->l2nleafs = cpu_to_le32(L2LPERCTL); 3975 dcp->leafidx = cpu_to_le32(CTLLEAFIND); 3976 dcp->height = cpu_to_le32(5); 3977 dcp->budmin = L2BPERDMAP + L2LPERCTL * level; 3978 3979 /* 3980 * initialize the leaves of current level that were not covered 3981 * by the specified input block range (i.e. the leaves have no 3982 * low level dmapctl or dmap). 3983 */ 3984 cp = &dcp->stree[CTLLEAFIND + i]; 3985 for (; i < LPERCTL; i++) 3986 *cp++ = NOFREE; 3987 3988 /* build the dmap's binary buddy summary tree */ 3989 return (dbInitTree((struct dmaptree *) dcp)); 3990 } 3991 3992 3993 /* 3994 * NAME: dbGetL2AGSize()/ujfs_getagl2size() 3995 * 3996 * FUNCTION: Determine log2(allocation group size) from aggregate size 3997 * 3998 * PARAMETERS: 3999 * nblocks - Number of blocks in aggregate 4000 * 4001 * RETURNS: log2(allocation group size) in aggregate blocks 4002 */ 4003 static int dbGetL2AGSize(s64 nblocks) 4004 { 4005 s64 sz; 4006 s64 m; 4007 int l2sz; 4008 4009 if (nblocks < BPERDMAP * MAXAG) 4010 return (L2BPERDMAP); 4011 4012 /* round up aggregate size to power of 2 */ 4013 m = ((u64) 1 << (64 - 1)); 4014 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) { 4015 if (m & nblocks) 4016 break; 4017 } 4018 4019 sz = (s64) 1 << l2sz; 4020 if (sz < nblocks) 4021 l2sz += 1; 4022 4023 /* agsize = roundupSize/max_number_of_ag */ 4024 return (l2sz - L2MAXAG); 4025 } 4026 4027 4028 /* 4029 * NAME: dbMapFileSizeToMapSize() 4030 * 4031 * FUNCTION: compute number of blocks the block allocation map file 4032 * can cover from the map file size; 4033 * 4034 * RETURNS: Number of blocks which can be covered by this block map file; 4035 */ 4036 4037 /* 4038 * maximum number of map pages at each level including control pages 4039 */ 4040 #define MAXL0PAGES (1 + LPERCTL) 4041 #define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES) 4042 #define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES) 4043 4044 /* 4045 * convert number of map pages to the zero origin top dmapctl level 4046 */ 4047 #define BMAPPGTOLEV(npages) \ 4048 (((npages) <= 3 + MAXL0PAGES) ? 0 : \ 4049 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2) 4050 4051 s64 dbMapFileSizeToMapSize(struct inode * ipbmap) 4052 { 4053 struct super_block *sb = ipbmap->i_sb; 4054 s64 nblocks; 4055 s64 npages, ndmaps; 4056 int level, i; 4057 int complete, factor; 4058 4059 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize; 4060 npages = nblocks >> JFS_SBI(sb)->l2nbperpage; 4061 level = BMAPPGTOLEV(npages); 4062 4063 /* At each level, accumulate the number of dmap pages covered by 4064 * the number of full child levels below it; 4065 * repeat for the last incomplete child level. 4066 */ 4067 ndmaps = 0; 4068 npages--; /* skip the first global control page */ 4069 /* skip higher level control pages above top level covered by map */ 4070 npages -= (2 - level); 4071 npages--; /* skip top level's control page */ 4072 for (i = level; i >= 0; i--) { 4073 factor = 4074 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1); 4075 complete = (u32) npages / factor; 4076 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL : 4077 ((i == 1) ? LPERCTL : 1)); 4078 4079 /* pages in last/incomplete child */ 4080 npages = (u32) npages % factor; 4081 /* skip incomplete child's level control page */ 4082 npages--; 4083 } 4084 4085 /* convert the number of dmaps into the number of blocks 4086 * which can be covered by the dmaps; 4087 */ 4088 nblocks = ndmaps << L2BPERDMAP; 4089 4090 return (nblocks); 4091 } 4092