1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) International Business Machines Corp., 2000-2004 4 * Portions Copyright (C) Tino Reichardt, 2012 5 */ 6 7 #include <linux/fs.h> 8 #include <linux/slab.h> 9 #include "jfs_incore.h" 10 #include "jfs_superblock.h" 11 #include "jfs_dmap.h" 12 #include "jfs_imap.h" 13 #include "jfs_lock.h" 14 #include "jfs_metapage.h" 15 #include "jfs_debug.h" 16 #include "jfs_discard.h" 17 18 /* 19 * SERIALIZATION of the Block Allocation Map. 20 * 21 * the working state of the block allocation map is accessed in 22 * two directions: 23 * 24 * 1) allocation and free requests that start at the dmap 25 * level and move up through the dmap control pages (i.e. 26 * the vast majority of requests). 27 * 28 * 2) allocation requests that start at dmap control page 29 * level and work down towards the dmaps. 30 * 31 * the serialization scheme used here is as follows. 32 * 33 * requests which start at the bottom are serialized against each 34 * other through buffers and each requests holds onto its buffers 35 * as it works it way up from a single dmap to the required level 36 * of dmap control page. 37 * requests that start at the top are serialized against each other 38 * and request that start from the bottom by the multiple read/single 39 * write inode lock of the bmap inode. requests starting at the top 40 * take this lock in write mode while request starting at the bottom 41 * take the lock in read mode. a single top-down request may proceed 42 * exclusively while multiple bottoms-up requests may proceed 43 * simultaneously (under the protection of busy buffers). 44 * 45 * in addition to information found in dmaps and dmap control pages, 46 * the working state of the block allocation map also includes read/ 47 * write information maintained in the bmap descriptor (i.e. total 48 * free block count, allocation group level free block counts). 49 * a single exclusive lock (BMAP_LOCK) is used to guard this information 50 * in the face of multiple-bottoms up requests. 51 * (lock ordering: IREAD_LOCK, BMAP_LOCK); 52 * 53 * accesses to the persistent state of the block allocation map (limited 54 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers. 55 */ 56 57 #define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock) 58 #define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock) 59 #define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock) 60 61 /* 62 * forward references 63 */ 64 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 65 int nblocks); 66 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval); 67 static int dbBackSplit(dmtree_t * tp, int leafno); 68 static int dbJoin(dmtree_t * tp, int leafno, int newval); 69 static void dbAdjTree(dmtree_t * tp, int leafno, int newval); 70 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, 71 int level); 72 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results); 73 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 74 int nblocks); 75 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno, 76 int nblocks, 77 int l2nb, s64 * results); 78 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 79 int nblocks); 80 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks, 81 int l2nb, 82 s64 * results); 83 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, 84 s64 * results); 85 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, 86 s64 * results); 87 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks); 88 static int dbFindBits(u32 word, int l2nb); 89 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno); 90 static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl); 91 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 92 int nblocks); 93 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 94 int nblocks); 95 static int dbMaxBud(u8 * cp); 96 static int blkstol2(s64 nb); 97 98 static int cntlz(u32 value); 99 static int cnttz(u32 word); 100 101 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 102 int nblocks); 103 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks); 104 static int dbInitDmapTree(struct dmap * dp); 105 static int dbInitTree(struct dmaptree * dtp); 106 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i); 107 static int dbGetL2AGSize(s64 nblocks); 108 109 /* 110 * buddy table 111 * 112 * table used for determining buddy sizes within characters of 113 * dmap bitmap words. the characters themselves serve as indexes 114 * into the table, with the table elements yielding the maximum 115 * binary buddy of free bits within the character. 116 */ 117 static const s8 budtab[256] = { 118 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 119 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 120 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 121 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 122 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 123 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 124 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 125 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 126 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 127 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 128 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 129 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 130 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 131 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 132 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 133 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1 134 }; 135 136 /* 137 * NAME: dbMount() 138 * 139 * FUNCTION: initializate the block allocation map. 140 * 141 * memory is allocated for the in-core bmap descriptor and 142 * the in-core descriptor is initialized from disk. 143 * 144 * PARAMETERS: 145 * ipbmap - pointer to in-core inode for the block map. 146 * 147 * RETURN VALUES: 148 * 0 - success 149 * -ENOMEM - insufficient memory 150 * -EIO - i/o error 151 * -EINVAL - wrong bmap data 152 */ 153 int dbMount(struct inode *ipbmap) 154 { 155 struct bmap *bmp; 156 struct dbmap_disk *dbmp_le; 157 struct metapage *mp; 158 int i, err; 159 160 /* 161 * allocate/initialize the in-memory bmap descriptor 162 */ 163 /* allocate memory for the in-memory bmap descriptor */ 164 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL); 165 if (bmp == NULL) 166 return -ENOMEM; 167 168 /* read the on-disk bmap descriptor. */ 169 mp = read_metapage(ipbmap, 170 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage, 171 PSIZE, 0); 172 if (mp == NULL) { 173 err = -EIO; 174 goto err_kfree_bmp; 175 } 176 177 /* copy the on-disk bmap descriptor to its in-memory version. */ 178 dbmp_le = (struct dbmap_disk *) mp->data; 179 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize); 180 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree); 181 182 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage); 183 if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE || 184 bmp->db_l2nbperpage < 0) { 185 err = -EINVAL; 186 goto err_release_metapage; 187 } 188 189 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag); 190 if (!bmp->db_numag) { 191 err = -EINVAL; 192 goto err_release_metapage; 193 } 194 195 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); 196 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag); 197 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref); 198 if (bmp->db_maxag >= MAXAG || bmp->db_maxag < 0 || 199 bmp->db_agpref >= MAXAG || bmp->db_agpref < 0) { 200 err = -EINVAL; 201 goto err_release_metapage; 202 } 203 204 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel); 205 bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight); 206 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth); 207 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart); 208 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size); 209 if (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG || 210 bmp->db_agl2size < 0) { 211 err = -EINVAL; 212 goto err_release_metapage; 213 } 214 215 if (((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) { 216 err = -EINVAL; 217 goto err_release_metapage; 218 } 219 220 for (i = 0; i < MAXAG; i++) 221 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]); 222 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize); 223 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud; 224 225 /* release the buffer. */ 226 release_metapage(mp); 227 228 /* bind the bmap inode and the bmap descriptor to each other. */ 229 bmp->db_ipbmap = ipbmap; 230 JFS_SBI(ipbmap->i_sb)->bmap = bmp; 231 232 memset(bmp->db_active, 0, sizeof(bmp->db_active)); 233 234 /* 235 * allocate/initialize the bmap lock 236 */ 237 BMAP_LOCK_INIT(bmp); 238 239 return (0); 240 241 err_release_metapage: 242 release_metapage(mp); 243 err_kfree_bmp: 244 kfree(bmp); 245 return err; 246 } 247 248 249 /* 250 * NAME: dbUnmount() 251 * 252 * FUNCTION: terminate the block allocation map in preparation for 253 * file system unmount. 254 * 255 * the in-core bmap descriptor is written to disk and 256 * the memory for this descriptor is freed. 257 * 258 * PARAMETERS: 259 * ipbmap - pointer to in-core inode for the block map. 260 * 261 * RETURN VALUES: 262 * 0 - success 263 * -EIO - i/o error 264 */ 265 int dbUnmount(struct inode *ipbmap, int mounterror) 266 { 267 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 268 269 if (!(mounterror || isReadOnly(ipbmap))) 270 dbSync(ipbmap); 271 272 /* 273 * Invalidate the page cache buffers 274 */ 275 truncate_inode_pages(ipbmap->i_mapping, 0); 276 277 /* free the memory for the in-memory bmap. */ 278 kfree(bmp); 279 JFS_SBI(ipbmap->i_sb)->bmap = NULL; 280 281 return (0); 282 } 283 284 /* 285 * dbSync() 286 */ 287 int dbSync(struct inode *ipbmap) 288 { 289 struct dbmap_disk *dbmp_le; 290 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 291 struct metapage *mp; 292 int i; 293 294 /* 295 * write bmap global control page 296 */ 297 /* get the buffer for the on-disk bmap descriptor. */ 298 mp = read_metapage(ipbmap, 299 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage, 300 PSIZE, 0); 301 if (mp == NULL) { 302 jfs_err("dbSync: read_metapage failed!"); 303 return -EIO; 304 } 305 /* copy the in-memory version of the bmap to the on-disk version */ 306 dbmp_le = (struct dbmap_disk *) mp->data; 307 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize); 308 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree); 309 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage); 310 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag); 311 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel); 312 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag); 313 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref); 314 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel); 315 dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight); 316 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth); 317 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart); 318 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size); 319 for (i = 0; i < MAXAG; i++) 320 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]); 321 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize); 322 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud; 323 324 /* write the buffer */ 325 write_metapage(mp); 326 327 /* 328 * write out dirty pages of bmap 329 */ 330 filemap_write_and_wait(ipbmap->i_mapping); 331 332 diWriteSpecial(ipbmap, 0); 333 334 return (0); 335 } 336 337 /* 338 * NAME: dbFree() 339 * 340 * FUNCTION: free the specified block range from the working block 341 * allocation map. 342 * 343 * the blocks will be free from the working map one dmap 344 * at a time. 345 * 346 * PARAMETERS: 347 * ip - pointer to in-core inode; 348 * blkno - starting block number to be freed. 349 * nblocks - number of blocks to be freed. 350 * 351 * RETURN VALUES: 352 * 0 - success 353 * -EIO - i/o error 354 */ 355 int dbFree(struct inode *ip, s64 blkno, s64 nblocks) 356 { 357 struct metapage *mp; 358 struct dmap *dp; 359 int nb, rc; 360 s64 lblkno, rem; 361 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 362 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 363 struct super_block *sb = ipbmap->i_sb; 364 365 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 366 367 /* block to be freed better be within the mapsize. */ 368 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) { 369 IREAD_UNLOCK(ipbmap); 370 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", 371 (unsigned long long) blkno, 372 (unsigned long long) nblocks); 373 jfs_error(ip->i_sb, "block to be freed is outside the map\n"); 374 return -EIO; 375 } 376 377 /** 378 * TRIM the blocks, when mounted with discard option 379 */ 380 if (JFS_SBI(sb)->flag & JFS_DISCARD) 381 if (JFS_SBI(sb)->minblks_trim <= nblocks) 382 jfs_issue_discard(ipbmap, blkno, nblocks); 383 384 /* 385 * free the blocks a dmap at a time. 386 */ 387 mp = NULL; 388 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 389 /* release previous dmap if any */ 390 if (mp) { 391 write_metapage(mp); 392 } 393 394 /* get the buffer for the current dmap. */ 395 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 396 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 397 if (mp == NULL) { 398 IREAD_UNLOCK(ipbmap); 399 return -EIO; 400 } 401 dp = (struct dmap *) mp->data; 402 403 /* determine the number of blocks to be freed from 404 * this dmap. 405 */ 406 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 407 408 /* free the blocks. */ 409 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) { 410 jfs_error(ip->i_sb, "error in block map\n"); 411 release_metapage(mp); 412 IREAD_UNLOCK(ipbmap); 413 return (rc); 414 } 415 } 416 417 /* write the last buffer. */ 418 if (mp) 419 write_metapage(mp); 420 421 IREAD_UNLOCK(ipbmap); 422 423 return (0); 424 } 425 426 427 /* 428 * NAME: dbUpdatePMap() 429 * 430 * FUNCTION: update the allocation state (free or allocate) of the 431 * specified block range in the persistent block allocation map. 432 * 433 * the blocks will be updated in the persistent map one 434 * dmap at a time. 435 * 436 * PARAMETERS: 437 * ipbmap - pointer to in-core inode for the block map. 438 * free - 'true' if block range is to be freed from the persistent 439 * map; 'false' if it is to be allocated. 440 * blkno - starting block number of the range. 441 * nblocks - number of contiguous blocks in the range. 442 * tblk - transaction block; 443 * 444 * RETURN VALUES: 445 * 0 - success 446 * -EIO - i/o error 447 */ 448 int 449 dbUpdatePMap(struct inode *ipbmap, 450 int free, s64 blkno, s64 nblocks, struct tblock * tblk) 451 { 452 int nblks, dbitno, wbitno, rbits; 453 int word, nbits, nwords; 454 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 455 s64 lblkno, rem, lastlblkno; 456 u32 mask; 457 struct dmap *dp; 458 struct metapage *mp; 459 struct jfs_log *log; 460 int lsn, difft, diffp; 461 unsigned long flags; 462 463 /* the blocks better be within the mapsize. */ 464 if (blkno + nblocks > bmp->db_mapsize) { 465 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", 466 (unsigned long long) blkno, 467 (unsigned long long) nblocks); 468 jfs_error(ipbmap->i_sb, "blocks are outside the map\n"); 469 return -EIO; 470 } 471 472 /* compute delta of transaction lsn from log syncpt */ 473 lsn = tblk->lsn; 474 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log; 475 logdiff(difft, lsn, log); 476 477 /* 478 * update the block state a dmap at a time. 479 */ 480 mp = NULL; 481 lastlblkno = 0; 482 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) { 483 /* get the buffer for the current dmap. */ 484 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 485 if (lblkno != lastlblkno) { 486 if (mp) { 487 write_metapage(mp); 488 } 489 490 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 491 0); 492 if (mp == NULL) 493 return -EIO; 494 metapage_wait_for_io(mp); 495 } 496 dp = (struct dmap *) mp->data; 497 498 /* determine the bit number and word within the dmap of 499 * the starting block. also determine how many blocks 500 * are to be updated within this dmap. 501 */ 502 dbitno = blkno & (BPERDMAP - 1); 503 word = dbitno >> L2DBWORD; 504 nblks = min(rem, (s64)BPERDMAP - dbitno); 505 506 /* update the bits of the dmap words. the first and last 507 * words may only have a subset of their bits updated. if 508 * this is the case, we'll work against that word (i.e. 509 * partial first and/or last) only in a single pass. a 510 * single pass will also be used to update all words that 511 * are to have all their bits updated. 512 */ 513 for (rbits = nblks; rbits > 0; 514 rbits -= nbits, dbitno += nbits) { 515 /* determine the bit number within the word and 516 * the number of bits within the word. 517 */ 518 wbitno = dbitno & (DBWORD - 1); 519 nbits = min(rbits, DBWORD - wbitno); 520 521 /* check if only part of the word is to be updated. */ 522 if (nbits < DBWORD) { 523 /* update (free or allocate) the bits 524 * in this word. 525 */ 526 mask = 527 (ONES << (DBWORD - nbits) >> wbitno); 528 if (free) 529 dp->pmap[word] &= 530 cpu_to_le32(~mask); 531 else 532 dp->pmap[word] |= 533 cpu_to_le32(mask); 534 535 word += 1; 536 } else { 537 /* one or more words are to have all 538 * their bits updated. determine how 539 * many words and how many bits. 540 */ 541 nwords = rbits >> L2DBWORD; 542 nbits = nwords << L2DBWORD; 543 544 /* update (free or allocate) the bits 545 * in these words. 546 */ 547 if (free) 548 memset(&dp->pmap[word], 0, 549 nwords * 4); 550 else 551 memset(&dp->pmap[word], (int) ONES, 552 nwords * 4); 553 554 word += nwords; 555 } 556 } 557 558 /* 559 * update dmap lsn 560 */ 561 if (lblkno == lastlblkno) 562 continue; 563 564 lastlblkno = lblkno; 565 566 LOGSYNC_LOCK(log, flags); 567 if (mp->lsn != 0) { 568 /* inherit older/smaller lsn */ 569 logdiff(diffp, mp->lsn, log); 570 if (difft < diffp) { 571 mp->lsn = lsn; 572 573 /* move bp after tblock in logsync list */ 574 list_move(&mp->synclist, &tblk->synclist); 575 } 576 577 /* inherit younger/larger clsn */ 578 logdiff(difft, tblk->clsn, log); 579 logdiff(diffp, mp->clsn, log); 580 if (difft > diffp) 581 mp->clsn = tblk->clsn; 582 } else { 583 mp->log = log; 584 mp->lsn = lsn; 585 586 /* insert bp after tblock in logsync list */ 587 log->count++; 588 list_add(&mp->synclist, &tblk->synclist); 589 590 mp->clsn = tblk->clsn; 591 } 592 LOGSYNC_UNLOCK(log, flags); 593 } 594 595 /* write the last buffer. */ 596 if (mp) { 597 write_metapage(mp); 598 } 599 600 return (0); 601 } 602 603 604 /* 605 * NAME: dbNextAG() 606 * 607 * FUNCTION: find the preferred allocation group for new allocations. 608 * 609 * Within the allocation groups, we maintain a preferred 610 * allocation group which consists of a group with at least 611 * average free space. It is the preferred group that we target 612 * new inode allocation towards. The tie-in between inode 613 * allocation and block allocation occurs as we allocate the 614 * first (data) block of an inode and specify the inode (block) 615 * as the allocation hint for this block. 616 * 617 * We try to avoid having more than one open file growing in 618 * an allocation group, as this will lead to fragmentation. 619 * This differs from the old OS/2 method of trying to keep 620 * empty ags around for large allocations. 621 * 622 * PARAMETERS: 623 * ipbmap - pointer to in-core inode for the block map. 624 * 625 * RETURN VALUES: 626 * the preferred allocation group number. 627 */ 628 int dbNextAG(struct inode *ipbmap) 629 { 630 s64 avgfree; 631 int agpref; 632 s64 hwm = 0; 633 int i; 634 int next_best = -1; 635 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 636 637 BMAP_LOCK(bmp); 638 639 /* determine the average number of free blocks within the ags. */ 640 avgfree = (u32)bmp->db_nfree / bmp->db_numag; 641 642 /* 643 * if the current preferred ag does not have an active allocator 644 * and has at least average freespace, return it 645 */ 646 agpref = bmp->db_agpref; 647 if ((atomic_read(&bmp->db_active[agpref]) == 0) && 648 (bmp->db_agfree[agpref] >= avgfree)) 649 goto unlock; 650 651 /* From the last preferred ag, find the next one with at least 652 * average free space. 653 */ 654 for (i = 0 ; i < bmp->db_numag; i++, agpref++) { 655 if (agpref == bmp->db_numag) 656 agpref = 0; 657 658 if (atomic_read(&bmp->db_active[agpref])) 659 /* open file is currently growing in this ag */ 660 continue; 661 if (bmp->db_agfree[agpref] >= avgfree) { 662 /* Return this one */ 663 bmp->db_agpref = agpref; 664 goto unlock; 665 } else if (bmp->db_agfree[agpref] > hwm) { 666 /* Less than avg. freespace, but best so far */ 667 hwm = bmp->db_agfree[agpref]; 668 next_best = agpref; 669 } 670 } 671 672 /* 673 * If no inactive ag was found with average freespace, use the 674 * next best 675 */ 676 if (next_best != -1) 677 bmp->db_agpref = next_best; 678 /* else leave db_agpref unchanged */ 679 unlock: 680 BMAP_UNLOCK(bmp); 681 682 /* return the preferred group. 683 */ 684 return (bmp->db_agpref); 685 } 686 687 /* 688 * NAME: dbAlloc() 689 * 690 * FUNCTION: attempt to allocate a specified number of contiguous free 691 * blocks from the working allocation block map. 692 * 693 * the block allocation policy uses hints and a multi-step 694 * approach. 695 * 696 * for allocation requests smaller than the number of blocks 697 * per dmap, we first try to allocate the new blocks 698 * immediately following the hint. if these blocks are not 699 * available, we try to allocate blocks near the hint. if 700 * no blocks near the hint are available, we next try to 701 * allocate within the same dmap as contains the hint. 702 * 703 * if no blocks are available in the dmap or the allocation 704 * request is larger than the dmap size, we try to allocate 705 * within the same allocation group as contains the hint. if 706 * this does not succeed, we finally try to allocate anywhere 707 * within the aggregate. 708 * 709 * we also try to allocate anywhere within the aggregate 710 * for allocation requests larger than the allocation group 711 * size or requests that specify no hint value. 712 * 713 * PARAMETERS: 714 * ip - pointer to in-core inode; 715 * hint - allocation hint. 716 * nblocks - number of contiguous blocks in the range. 717 * results - on successful return, set to the starting block number 718 * of the newly allocated contiguous range. 719 * 720 * RETURN VALUES: 721 * 0 - success 722 * -ENOSPC - insufficient disk resources 723 * -EIO - i/o error 724 */ 725 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results) 726 { 727 int rc, agno; 728 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 729 struct bmap *bmp; 730 struct metapage *mp; 731 s64 lblkno, blkno; 732 struct dmap *dp; 733 int l2nb; 734 s64 mapSize; 735 int writers; 736 737 /* assert that nblocks is valid */ 738 assert(nblocks > 0); 739 740 /* get the log2 number of blocks to be allocated. 741 * if the number of blocks is not a log2 multiple, 742 * it will be rounded up to the next log2 multiple. 743 */ 744 l2nb = BLKSTOL2(nblocks); 745 746 bmp = JFS_SBI(ip->i_sb)->bmap; 747 748 mapSize = bmp->db_mapsize; 749 750 /* the hint should be within the map */ 751 if (hint >= mapSize) { 752 jfs_error(ip->i_sb, "the hint is outside the map\n"); 753 return -EIO; 754 } 755 756 /* if the number of blocks to be allocated is greater than the 757 * allocation group size, try to allocate anywhere. 758 */ 759 if (l2nb > bmp->db_agl2size) { 760 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 761 762 rc = dbAllocAny(bmp, nblocks, l2nb, results); 763 764 goto write_unlock; 765 } 766 767 /* 768 * If no hint, let dbNextAG recommend an allocation group 769 */ 770 if (hint == 0) 771 goto pref_ag; 772 773 /* we would like to allocate close to the hint. adjust the 774 * hint to the block following the hint since the allocators 775 * will start looking for free space starting at this point. 776 */ 777 blkno = hint + 1; 778 779 if (blkno >= bmp->db_mapsize) 780 goto pref_ag; 781 782 agno = blkno >> bmp->db_agl2size; 783 784 /* check if blkno crosses over into a new allocation group. 785 * if so, check if we should allow allocations within this 786 * allocation group. 787 */ 788 if ((blkno & (bmp->db_agsize - 1)) == 0) 789 /* check if the AG is currently being written to. 790 * if so, call dbNextAG() to find a non-busy 791 * AG with sufficient free space. 792 */ 793 if (atomic_read(&bmp->db_active[agno])) 794 goto pref_ag; 795 796 /* check if the allocation request size can be satisfied from a 797 * single dmap. if so, try to allocate from the dmap containing 798 * the hint using a tiered strategy. 799 */ 800 if (nblocks <= BPERDMAP) { 801 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 802 803 /* get the buffer for the dmap containing the hint. 804 */ 805 rc = -EIO; 806 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 807 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 808 if (mp == NULL) 809 goto read_unlock; 810 811 dp = (struct dmap *) mp->data; 812 813 /* first, try to satisfy the allocation request with the 814 * blocks beginning at the hint. 815 */ 816 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks)) 817 != -ENOSPC) { 818 if (rc == 0) { 819 *results = blkno; 820 mark_metapage_dirty(mp); 821 } 822 823 release_metapage(mp); 824 goto read_unlock; 825 } 826 827 writers = atomic_read(&bmp->db_active[agno]); 828 if ((writers > 1) || 829 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) { 830 /* 831 * Someone else is writing in this allocation 832 * group. To avoid fragmenting, try another ag 833 */ 834 release_metapage(mp); 835 IREAD_UNLOCK(ipbmap); 836 goto pref_ag; 837 } 838 839 /* next, try to satisfy the allocation request with blocks 840 * near the hint. 841 */ 842 if ((rc = 843 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results)) 844 != -ENOSPC) { 845 if (rc == 0) 846 mark_metapage_dirty(mp); 847 848 release_metapage(mp); 849 goto read_unlock; 850 } 851 852 /* try to satisfy the allocation request with blocks within 853 * the same dmap as the hint. 854 */ 855 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results)) 856 != -ENOSPC) { 857 if (rc == 0) 858 mark_metapage_dirty(mp); 859 860 release_metapage(mp); 861 goto read_unlock; 862 } 863 864 release_metapage(mp); 865 IREAD_UNLOCK(ipbmap); 866 } 867 868 /* try to satisfy the allocation request with blocks within 869 * the same allocation group as the hint. 870 */ 871 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 872 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC) 873 goto write_unlock; 874 875 IWRITE_UNLOCK(ipbmap); 876 877 878 pref_ag: 879 /* 880 * Let dbNextAG recommend a preferred allocation group 881 */ 882 agno = dbNextAG(ipbmap); 883 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 884 885 /* Try to allocate within this allocation group. if that fails, try to 886 * allocate anywhere in the map. 887 */ 888 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC) 889 rc = dbAllocAny(bmp, nblocks, l2nb, results); 890 891 write_unlock: 892 IWRITE_UNLOCK(ipbmap); 893 894 return (rc); 895 896 read_unlock: 897 IREAD_UNLOCK(ipbmap); 898 899 return (rc); 900 } 901 902 /* 903 * NAME: dbReAlloc() 904 * 905 * FUNCTION: attempt to extend a current allocation by a specified 906 * number of blocks. 907 * 908 * this routine attempts to satisfy the allocation request 909 * by first trying to extend the existing allocation in 910 * place by allocating the additional blocks as the blocks 911 * immediately following the current allocation. if these 912 * blocks are not available, this routine will attempt to 913 * allocate a new set of contiguous blocks large enough 914 * to cover the existing allocation plus the additional 915 * number of blocks required. 916 * 917 * PARAMETERS: 918 * ip - pointer to in-core inode requiring allocation. 919 * blkno - starting block of the current allocation. 920 * nblocks - number of contiguous blocks within the current 921 * allocation. 922 * addnblocks - number of blocks to add to the allocation. 923 * results - on successful return, set to the starting block number 924 * of the existing allocation if the existing allocation 925 * was extended in place or to a newly allocated contiguous 926 * range if the existing allocation could not be extended 927 * in place. 928 * 929 * RETURN VALUES: 930 * 0 - success 931 * -ENOSPC - insufficient disk resources 932 * -EIO - i/o error 933 */ 934 int 935 dbReAlloc(struct inode *ip, 936 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results) 937 { 938 int rc; 939 940 /* try to extend the allocation in place. 941 */ 942 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) { 943 *results = blkno; 944 return (0); 945 } else { 946 if (rc != -ENOSPC) 947 return (rc); 948 } 949 950 /* could not extend the allocation in place, so allocate a 951 * new set of blocks for the entire request (i.e. try to get 952 * a range of contiguous blocks large enough to cover the 953 * existing allocation plus the additional blocks.) 954 */ 955 return (dbAlloc 956 (ip, blkno + nblocks - 1, addnblocks + nblocks, results)); 957 } 958 959 960 /* 961 * NAME: dbExtend() 962 * 963 * FUNCTION: attempt to extend a current allocation by a specified 964 * number of blocks. 965 * 966 * this routine attempts to satisfy the allocation request 967 * by first trying to extend the existing allocation in 968 * place by allocating the additional blocks as the blocks 969 * immediately following the current allocation. 970 * 971 * PARAMETERS: 972 * ip - pointer to in-core inode requiring allocation. 973 * blkno - starting block of the current allocation. 974 * nblocks - number of contiguous blocks within the current 975 * allocation. 976 * addnblocks - number of blocks to add to the allocation. 977 * 978 * RETURN VALUES: 979 * 0 - success 980 * -ENOSPC - insufficient disk resources 981 * -EIO - i/o error 982 */ 983 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks) 984 { 985 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb); 986 s64 lblkno, lastblkno, extblkno; 987 uint rel_block; 988 struct metapage *mp; 989 struct dmap *dp; 990 int rc; 991 struct inode *ipbmap = sbi->ipbmap; 992 struct bmap *bmp; 993 994 /* 995 * We don't want a non-aligned extent to cross a page boundary 996 */ 997 if (((rel_block = blkno & (sbi->nbperpage - 1))) && 998 (rel_block + nblocks + addnblocks > sbi->nbperpage)) 999 return -ENOSPC; 1000 1001 /* get the last block of the current allocation */ 1002 lastblkno = blkno + nblocks - 1; 1003 1004 /* determine the block number of the block following 1005 * the existing allocation. 1006 */ 1007 extblkno = lastblkno + 1; 1008 1009 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 1010 1011 /* better be within the file system */ 1012 bmp = sbi->bmap; 1013 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) { 1014 IREAD_UNLOCK(ipbmap); 1015 jfs_error(ip->i_sb, "the block is outside the filesystem\n"); 1016 return -EIO; 1017 } 1018 1019 /* we'll attempt to extend the current allocation in place by 1020 * allocating the additional blocks as the blocks immediately 1021 * following the current allocation. we only try to extend the 1022 * current allocation in place if the number of additional blocks 1023 * can fit into a dmap, the last block of the current allocation 1024 * is not the last block of the file system, and the start of the 1025 * inplace extension is not on an allocation group boundary. 1026 */ 1027 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize || 1028 (extblkno & (bmp->db_agsize - 1)) == 0) { 1029 IREAD_UNLOCK(ipbmap); 1030 return -ENOSPC; 1031 } 1032 1033 /* get the buffer for the dmap containing the first block 1034 * of the extension. 1035 */ 1036 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage); 1037 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 1038 if (mp == NULL) { 1039 IREAD_UNLOCK(ipbmap); 1040 return -EIO; 1041 } 1042 1043 dp = (struct dmap *) mp->data; 1044 1045 /* try to allocate the blocks immediately following the 1046 * current allocation. 1047 */ 1048 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks); 1049 1050 IREAD_UNLOCK(ipbmap); 1051 1052 /* were we successful ? */ 1053 if (rc == 0) 1054 write_metapage(mp); 1055 else 1056 /* we were not successful */ 1057 release_metapage(mp); 1058 1059 return (rc); 1060 } 1061 1062 1063 /* 1064 * NAME: dbAllocNext() 1065 * 1066 * FUNCTION: attempt to allocate the blocks of the specified block 1067 * range within a dmap. 1068 * 1069 * PARAMETERS: 1070 * bmp - pointer to bmap descriptor 1071 * dp - pointer to dmap. 1072 * blkno - starting block number of the range. 1073 * nblocks - number of contiguous free blocks of the range. 1074 * 1075 * RETURN VALUES: 1076 * 0 - success 1077 * -ENOSPC - insufficient disk resources 1078 * -EIO - i/o error 1079 * 1080 * serialization: IREAD_LOCK(ipbmap) held on entry/exit; 1081 */ 1082 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 1083 int nblocks) 1084 { 1085 int dbitno, word, rembits, nb, nwords, wbitno, nw; 1086 int l2size; 1087 s8 *leaf; 1088 u32 mask; 1089 1090 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { 1091 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); 1092 return -EIO; 1093 } 1094 1095 /* pick up a pointer to the leaves of the dmap tree. 1096 */ 1097 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx); 1098 1099 /* determine the bit number and word within the dmap of the 1100 * starting block. 1101 */ 1102 dbitno = blkno & (BPERDMAP - 1); 1103 word = dbitno >> L2DBWORD; 1104 1105 /* check if the specified block range is contained within 1106 * this dmap. 1107 */ 1108 if (dbitno + nblocks > BPERDMAP) 1109 return -ENOSPC; 1110 1111 /* check if the starting leaf indicates that anything 1112 * is free. 1113 */ 1114 if (leaf[word] == NOFREE) 1115 return -ENOSPC; 1116 1117 /* check the dmaps words corresponding to block range to see 1118 * if the block range is free. not all bits of the first and 1119 * last words may be contained within the block range. if this 1120 * is the case, we'll work against those words (i.e. partial first 1121 * and/or last) on an individual basis (a single pass) and examine 1122 * the actual bits to determine if they are free. a single pass 1123 * will be used for all dmap words fully contained within the 1124 * specified range. within this pass, the leaves of the dmap 1125 * tree will be examined to determine if the blocks are free. a 1126 * single leaf may describe the free space of multiple dmap 1127 * words, so we may visit only a subset of the actual leaves 1128 * corresponding to the dmap words of the block range. 1129 */ 1130 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 1131 /* determine the bit number within the word and 1132 * the number of bits within the word. 1133 */ 1134 wbitno = dbitno & (DBWORD - 1); 1135 nb = min(rembits, DBWORD - wbitno); 1136 1137 /* check if only part of the word is to be examined. 1138 */ 1139 if (nb < DBWORD) { 1140 /* check if the bits are free. 1141 */ 1142 mask = (ONES << (DBWORD - nb) >> wbitno); 1143 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask) 1144 return -ENOSPC; 1145 1146 word += 1; 1147 } else { 1148 /* one or more dmap words are fully contained 1149 * within the block range. determine how many 1150 * words and how many bits. 1151 */ 1152 nwords = rembits >> L2DBWORD; 1153 nb = nwords << L2DBWORD; 1154 1155 /* now examine the appropriate leaves to determine 1156 * if the blocks are free. 1157 */ 1158 while (nwords > 0) { 1159 /* does the leaf describe any free space ? 1160 */ 1161 if (leaf[word] < BUDMIN) 1162 return -ENOSPC; 1163 1164 /* determine the l2 number of bits provided 1165 * by this leaf. 1166 */ 1167 l2size = 1168 min_t(int, leaf[word], NLSTOL2BSZ(nwords)); 1169 1170 /* determine how many words were handled. 1171 */ 1172 nw = BUDSIZE(l2size, BUDMIN); 1173 1174 nwords -= nw; 1175 word += nw; 1176 } 1177 } 1178 } 1179 1180 /* allocate the blocks. 1181 */ 1182 return (dbAllocDmap(bmp, dp, blkno, nblocks)); 1183 } 1184 1185 1186 /* 1187 * NAME: dbAllocNear() 1188 * 1189 * FUNCTION: attempt to allocate a number of contiguous free blocks near 1190 * a specified block (hint) within a dmap. 1191 * 1192 * starting with the dmap leaf that covers the hint, we'll 1193 * check the next four contiguous leaves for sufficient free 1194 * space. if sufficient free space is found, we'll allocate 1195 * the desired free space. 1196 * 1197 * PARAMETERS: 1198 * bmp - pointer to bmap descriptor 1199 * dp - pointer to dmap. 1200 * blkno - block number to allocate near. 1201 * nblocks - actual number of contiguous free blocks desired. 1202 * l2nb - log2 number of contiguous free blocks desired. 1203 * results - on successful return, set to the starting block number 1204 * of the newly allocated range. 1205 * 1206 * RETURN VALUES: 1207 * 0 - success 1208 * -ENOSPC - insufficient disk resources 1209 * -EIO - i/o error 1210 * 1211 * serialization: IREAD_LOCK(ipbmap) held on entry/exit; 1212 */ 1213 static int 1214 dbAllocNear(struct bmap * bmp, 1215 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results) 1216 { 1217 int word, lword, rc; 1218 s8 *leaf; 1219 1220 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { 1221 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); 1222 return -EIO; 1223 } 1224 1225 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx); 1226 1227 /* determine the word within the dmap that holds the hint 1228 * (i.e. blkno). also, determine the last word in the dmap 1229 * that we'll include in our examination. 1230 */ 1231 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 1232 lword = min(word + 4, LPERDMAP); 1233 1234 /* examine the leaves for sufficient free space. 1235 */ 1236 for (; word < lword; word++) { 1237 /* does the leaf describe sufficient free space ? 1238 */ 1239 if (leaf[word] < l2nb) 1240 continue; 1241 1242 /* determine the block number within the file system 1243 * of the first block described by this dmap word. 1244 */ 1245 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD); 1246 1247 /* if not all bits of the dmap word are free, get the 1248 * starting bit number within the dmap word of the required 1249 * string of free bits and adjust the block number with the 1250 * value. 1251 */ 1252 if (leaf[word] < BUDMIN) 1253 blkno += 1254 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb); 1255 1256 /* allocate the blocks. 1257 */ 1258 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 1259 *results = blkno; 1260 1261 return (rc); 1262 } 1263 1264 return -ENOSPC; 1265 } 1266 1267 1268 /* 1269 * NAME: dbAllocAG() 1270 * 1271 * FUNCTION: attempt to allocate the specified number of contiguous 1272 * free blocks within the specified allocation group. 1273 * 1274 * unless the allocation group size is equal to the number 1275 * of blocks per dmap, the dmap control pages will be used to 1276 * find the required free space, if available. we start the 1277 * search at the highest dmap control page level which 1278 * distinctly describes the allocation group's free space 1279 * (i.e. the highest level at which the allocation group's 1280 * free space is not mixed in with that of any other group). 1281 * in addition, we start the search within this level at a 1282 * height of the dmapctl dmtree at which the nodes distinctly 1283 * describe the allocation group's free space. at this height, 1284 * the allocation group's free space may be represented by 1 1285 * or two sub-trees, depending on the allocation group size. 1286 * we search the top nodes of these subtrees left to right for 1287 * sufficient free space. if sufficient free space is found, 1288 * the subtree is searched to find the leftmost leaf that 1289 * has free space. once we have made it to the leaf, we 1290 * move the search to the next lower level dmap control page 1291 * corresponding to this leaf. we continue down the dmap control 1292 * pages until we find the dmap that contains or starts the 1293 * sufficient free space and we allocate at this dmap. 1294 * 1295 * if the allocation group size is equal to the dmap size, 1296 * we'll start at the dmap corresponding to the allocation 1297 * group and attempt the allocation at this level. 1298 * 1299 * the dmap control page search is also not performed if the 1300 * allocation group is completely free and we go to the first 1301 * dmap of the allocation group to do the allocation. this is 1302 * done because the allocation group may be part (not the first 1303 * part) of a larger binary buddy system, causing the dmap 1304 * control pages to indicate no free space (NOFREE) within 1305 * the allocation group. 1306 * 1307 * PARAMETERS: 1308 * bmp - pointer to bmap descriptor 1309 * agno - allocation group number. 1310 * nblocks - actual number of contiguous free blocks desired. 1311 * l2nb - log2 number of contiguous free blocks desired. 1312 * results - on successful return, set to the starting block number 1313 * of the newly allocated range. 1314 * 1315 * RETURN VALUES: 1316 * 0 - success 1317 * -ENOSPC - insufficient disk resources 1318 * -EIO - i/o error 1319 * 1320 * note: IWRITE_LOCK(ipmap) held on entry/exit; 1321 */ 1322 static int 1323 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results) 1324 { 1325 struct metapage *mp; 1326 struct dmapctl *dcp; 1327 int rc, ti, i, k, m, n, agperlev; 1328 s64 blkno, lblkno; 1329 int budmin; 1330 1331 /* allocation request should not be for more than the 1332 * allocation group size. 1333 */ 1334 if (l2nb > bmp->db_agl2size) { 1335 jfs_error(bmp->db_ipbmap->i_sb, 1336 "allocation request is larger than the allocation group size\n"); 1337 return -EIO; 1338 } 1339 1340 /* determine the starting block number of the allocation 1341 * group. 1342 */ 1343 blkno = (s64) agno << bmp->db_agl2size; 1344 1345 /* check if the allocation group size is the minimum allocation 1346 * group size or if the allocation group is completely free. if 1347 * the allocation group size is the minimum size of BPERDMAP (i.e. 1348 * 1 dmap), there is no need to search the dmap control page (below) 1349 * that fully describes the allocation group since the allocation 1350 * group is already fully described by a dmap. in this case, we 1351 * just call dbAllocCtl() to search the dmap tree and allocate the 1352 * required space if available. 1353 * 1354 * if the allocation group is completely free, dbAllocCtl() is 1355 * also called to allocate the required space. this is done for 1356 * two reasons. first, it makes no sense searching the dmap control 1357 * pages for free space when we know that free space exists. second, 1358 * the dmap control pages may indicate that the allocation group 1359 * has no free space if the allocation group is part (not the first 1360 * part) of a larger binary buddy system. 1361 */ 1362 if (bmp->db_agsize == BPERDMAP 1363 || bmp->db_agfree[agno] == bmp->db_agsize) { 1364 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1365 if ((rc == -ENOSPC) && 1366 (bmp->db_agfree[agno] == bmp->db_agsize)) { 1367 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n", 1368 (unsigned long long) blkno, 1369 (unsigned long long) nblocks); 1370 jfs_error(bmp->db_ipbmap->i_sb, 1371 "dbAllocCtl failed in free AG\n"); 1372 } 1373 return (rc); 1374 } 1375 1376 /* the buffer for the dmap control page that fully describes the 1377 * allocation group. 1378 */ 1379 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel); 1380 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1381 if (mp == NULL) 1382 return -EIO; 1383 dcp = (struct dmapctl *) mp->data; 1384 budmin = dcp->budmin; 1385 1386 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1387 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 1388 release_metapage(mp); 1389 return -EIO; 1390 } 1391 1392 /* search the subtree(s) of the dmap control page that describes 1393 * the allocation group, looking for sufficient free space. to begin, 1394 * determine how many allocation groups are represented in a dmap 1395 * control page at the control page level (i.e. L0, L1, L2) that 1396 * fully describes an allocation group. next, determine the starting 1397 * tree index of this allocation group within the control page. 1398 */ 1399 agperlev = 1400 (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth; 1401 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1)); 1402 1403 /* dmap control page trees fan-out by 4 and a single allocation 1404 * group may be described by 1 or 2 subtrees within the ag level 1405 * dmap control page, depending upon the ag size. examine the ag's 1406 * subtrees for sufficient free space, starting with the leftmost 1407 * subtree. 1408 */ 1409 for (i = 0; i < bmp->db_agwidth; i++, ti++) { 1410 /* is there sufficient free space ? 1411 */ 1412 if (l2nb > dcp->stree[ti]) 1413 continue; 1414 1415 /* sufficient free space found in a subtree. now search down 1416 * the subtree to find the leftmost leaf that describes this 1417 * free space. 1418 */ 1419 for (k = bmp->db_agheight; k > 0; k--) { 1420 for (n = 0, m = (ti << 2) + 1; n < 4; n++) { 1421 if (l2nb <= dcp->stree[m + n]) { 1422 ti = m + n; 1423 break; 1424 } 1425 } 1426 if (n == 4) { 1427 jfs_error(bmp->db_ipbmap->i_sb, 1428 "failed descending stree\n"); 1429 release_metapage(mp); 1430 return -EIO; 1431 } 1432 } 1433 1434 /* determine the block number within the file system 1435 * that corresponds to this leaf. 1436 */ 1437 if (bmp->db_aglevel == 2) 1438 blkno = 0; 1439 else if (bmp->db_aglevel == 1) 1440 blkno &= ~(MAXL1SIZE - 1); 1441 else /* bmp->db_aglevel == 0 */ 1442 blkno &= ~(MAXL0SIZE - 1); 1443 1444 blkno += 1445 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin; 1446 1447 /* release the buffer in preparation for going down 1448 * the next level of dmap control pages. 1449 */ 1450 release_metapage(mp); 1451 1452 /* check if we need to continue to search down the lower 1453 * level dmap control pages. we need to if the number of 1454 * blocks required is less than maximum number of blocks 1455 * described at the next lower level. 1456 */ 1457 if (l2nb < budmin) { 1458 1459 /* search the lower level dmap control pages to get 1460 * the starting block number of the dmap that 1461 * contains or starts off the free space. 1462 */ 1463 if ((rc = 1464 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1, 1465 &blkno))) { 1466 if (rc == -ENOSPC) { 1467 jfs_error(bmp->db_ipbmap->i_sb, 1468 "control page inconsistent\n"); 1469 return -EIO; 1470 } 1471 return (rc); 1472 } 1473 } 1474 1475 /* allocate the blocks. 1476 */ 1477 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1478 if (rc == -ENOSPC) { 1479 jfs_error(bmp->db_ipbmap->i_sb, 1480 "unable to allocate blocks\n"); 1481 rc = -EIO; 1482 } 1483 return (rc); 1484 } 1485 1486 /* no space in the allocation group. release the buffer and 1487 * return -ENOSPC. 1488 */ 1489 release_metapage(mp); 1490 1491 return -ENOSPC; 1492 } 1493 1494 1495 /* 1496 * NAME: dbAllocAny() 1497 * 1498 * FUNCTION: attempt to allocate the specified number of contiguous 1499 * free blocks anywhere in the file system. 1500 * 1501 * dbAllocAny() attempts to find the sufficient free space by 1502 * searching down the dmap control pages, starting with the 1503 * highest level (i.e. L0, L1, L2) control page. if free space 1504 * large enough to satisfy the desired free space is found, the 1505 * desired free space is allocated. 1506 * 1507 * PARAMETERS: 1508 * bmp - pointer to bmap descriptor 1509 * nblocks - actual number of contiguous free blocks desired. 1510 * l2nb - log2 number of contiguous free blocks desired. 1511 * results - on successful return, set to the starting block number 1512 * of the newly allocated range. 1513 * 1514 * RETURN VALUES: 1515 * 0 - success 1516 * -ENOSPC - insufficient disk resources 1517 * -EIO - i/o error 1518 * 1519 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1520 */ 1521 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results) 1522 { 1523 int rc; 1524 s64 blkno = 0; 1525 1526 /* starting with the top level dmap control page, search 1527 * down the dmap control levels for sufficient free space. 1528 * if free space is found, dbFindCtl() returns the starting 1529 * block number of the dmap that contains or starts off the 1530 * range of free space. 1531 */ 1532 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno))) 1533 return (rc); 1534 1535 /* allocate the blocks. 1536 */ 1537 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); 1538 if (rc == -ENOSPC) { 1539 jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n"); 1540 return -EIO; 1541 } 1542 return (rc); 1543 } 1544 1545 1546 /* 1547 * NAME: dbDiscardAG() 1548 * 1549 * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG 1550 * 1551 * algorithm: 1552 * 1) allocate blocks, as large as possible and save them 1553 * while holding IWRITE_LOCK on ipbmap 1554 * 2) trim all these saved block/length values 1555 * 3) mark the blocks free again 1556 * 1557 * benefit: 1558 * - we work only on one ag at some time, minimizing how long we 1559 * need to lock ipbmap 1560 * - reading / writing the fs is possible most time, even on 1561 * trimming 1562 * 1563 * downside: 1564 * - we write two times to the dmapctl and dmap pages 1565 * - but for me, this seems the best way, better ideas? 1566 * /TR 2012 1567 * 1568 * PARAMETERS: 1569 * ip - pointer to in-core inode 1570 * agno - ag to trim 1571 * minlen - minimum value of contiguous blocks 1572 * 1573 * RETURN VALUES: 1574 * s64 - actual number of blocks trimmed 1575 */ 1576 s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen) 1577 { 1578 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 1579 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 1580 s64 nblocks, blkno; 1581 u64 trimmed = 0; 1582 int rc, l2nb; 1583 struct super_block *sb = ipbmap->i_sb; 1584 1585 struct range2trim { 1586 u64 blkno; 1587 u64 nblocks; 1588 } *totrim, *tt; 1589 1590 /* max blkno / nblocks pairs to trim */ 1591 int count = 0, range_cnt; 1592 u64 max_ranges; 1593 1594 /* prevent others from writing new stuff here, while trimming */ 1595 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); 1596 1597 nblocks = bmp->db_agfree[agno]; 1598 max_ranges = nblocks; 1599 do_div(max_ranges, minlen); 1600 range_cnt = min_t(u64, max_ranges + 1, 32 * 1024); 1601 totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS); 1602 if (totrim == NULL) { 1603 jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n"); 1604 IWRITE_UNLOCK(ipbmap); 1605 return 0; 1606 } 1607 1608 tt = totrim; 1609 while (nblocks >= minlen) { 1610 l2nb = BLKSTOL2(nblocks); 1611 1612 /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */ 1613 rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno); 1614 if (rc == 0) { 1615 tt->blkno = blkno; 1616 tt->nblocks = nblocks; 1617 tt++; count++; 1618 1619 /* the whole ag is free, trim now */ 1620 if (bmp->db_agfree[agno] == 0) 1621 break; 1622 1623 /* give a hint for the next while */ 1624 nblocks = bmp->db_agfree[agno]; 1625 continue; 1626 } else if (rc == -ENOSPC) { 1627 /* search for next smaller log2 block */ 1628 l2nb = BLKSTOL2(nblocks) - 1; 1629 nblocks = 1LL << l2nb; 1630 } else { 1631 /* Trim any already allocated blocks */ 1632 jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n"); 1633 break; 1634 } 1635 1636 /* check, if our trim array is full */ 1637 if (unlikely(count >= range_cnt - 1)) 1638 break; 1639 } 1640 IWRITE_UNLOCK(ipbmap); 1641 1642 tt->nblocks = 0; /* mark the current end */ 1643 for (tt = totrim; tt->nblocks != 0; tt++) { 1644 /* when mounted with online discard, dbFree() will 1645 * call jfs_issue_discard() itself */ 1646 if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) 1647 jfs_issue_discard(ip, tt->blkno, tt->nblocks); 1648 dbFree(ip, tt->blkno, tt->nblocks); 1649 trimmed += tt->nblocks; 1650 } 1651 kfree(totrim); 1652 1653 return trimmed; 1654 } 1655 1656 /* 1657 * NAME: dbFindCtl() 1658 * 1659 * FUNCTION: starting at a specified dmap control page level and block 1660 * number, search down the dmap control levels for a range of 1661 * contiguous free blocks large enough to satisfy an allocation 1662 * request for the specified number of free blocks. 1663 * 1664 * if sufficient contiguous free blocks are found, this routine 1665 * returns the starting block number within a dmap page that 1666 * contains or starts a range of contiqious free blocks that 1667 * is sufficient in size. 1668 * 1669 * PARAMETERS: 1670 * bmp - pointer to bmap descriptor 1671 * level - starting dmap control page level. 1672 * l2nb - log2 number of contiguous free blocks desired. 1673 * *blkno - on entry, starting block number for conducting the search. 1674 * on successful return, the first block within a dmap page 1675 * that contains or starts a range of contiguous free blocks. 1676 * 1677 * RETURN VALUES: 1678 * 0 - success 1679 * -ENOSPC - insufficient disk resources 1680 * -EIO - i/o error 1681 * 1682 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1683 */ 1684 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno) 1685 { 1686 int rc, leafidx, lev; 1687 s64 b, lblkno; 1688 struct dmapctl *dcp; 1689 int budmin; 1690 struct metapage *mp; 1691 1692 /* starting at the specified dmap control page level and block 1693 * number, search down the dmap control levels for the starting 1694 * block number of a dmap page that contains or starts off 1695 * sufficient free blocks. 1696 */ 1697 for (lev = level, b = *blkno; lev >= 0; lev--) { 1698 /* get the buffer of the dmap control page for the block 1699 * number and level (i.e. L0, L1, L2). 1700 */ 1701 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev); 1702 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1703 if (mp == NULL) 1704 return -EIO; 1705 dcp = (struct dmapctl *) mp->data; 1706 budmin = dcp->budmin; 1707 1708 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1709 jfs_error(bmp->db_ipbmap->i_sb, 1710 "Corrupt dmapctl page\n"); 1711 release_metapage(mp); 1712 return -EIO; 1713 } 1714 1715 /* search the tree within the dmap control page for 1716 * sufficient free space. if sufficient free space is found, 1717 * dbFindLeaf() returns the index of the leaf at which 1718 * free space was found. 1719 */ 1720 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx, true); 1721 1722 /* release the buffer. 1723 */ 1724 release_metapage(mp); 1725 1726 /* space found ? 1727 */ 1728 if (rc) { 1729 if (lev != level) { 1730 jfs_error(bmp->db_ipbmap->i_sb, 1731 "dmap inconsistent\n"); 1732 return -EIO; 1733 } 1734 return -ENOSPC; 1735 } 1736 1737 /* adjust the block number to reflect the location within 1738 * the dmap control page (i.e. the leaf) at which free 1739 * space was found. 1740 */ 1741 b += (((s64) leafidx) << budmin); 1742 1743 /* we stop the search at this dmap control page level if 1744 * the number of blocks required is greater than or equal 1745 * to the maximum number of blocks described at the next 1746 * (lower) level. 1747 */ 1748 if (l2nb >= budmin) 1749 break; 1750 } 1751 1752 *blkno = b; 1753 return (0); 1754 } 1755 1756 1757 /* 1758 * NAME: dbAllocCtl() 1759 * 1760 * FUNCTION: attempt to allocate a specified number of contiguous 1761 * blocks starting within a specific dmap. 1762 * 1763 * this routine is called by higher level routines that search 1764 * the dmap control pages above the actual dmaps for contiguous 1765 * free space. the result of successful searches by these 1766 * routines are the starting block numbers within dmaps, with 1767 * the dmaps themselves containing the desired contiguous free 1768 * space or starting a contiguous free space of desired size 1769 * that is made up of the blocks of one or more dmaps. these 1770 * calls should not fail due to insufficent resources. 1771 * 1772 * this routine is called in some cases where it is not known 1773 * whether it will fail due to insufficient resources. more 1774 * specifically, this occurs when allocating from an allocation 1775 * group whose size is equal to the number of blocks per dmap. 1776 * in this case, the dmap control pages are not examined prior 1777 * to calling this routine (to save pathlength) and the call 1778 * might fail. 1779 * 1780 * for a request size that fits within a dmap, this routine relies 1781 * upon the dmap's dmtree to find the requested contiguous free 1782 * space. for request sizes that are larger than a dmap, the 1783 * requested free space will start at the first block of the 1784 * first dmap (i.e. blkno). 1785 * 1786 * PARAMETERS: 1787 * bmp - pointer to bmap descriptor 1788 * nblocks - actual number of contiguous free blocks to allocate. 1789 * l2nb - log2 number of contiguous free blocks to allocate. 1790 * blkno - starting block number of the dmap to start the allocation 1791 * from. 1792 * results - on successful return, set to the starting block number 1793 * of the newly allocated range. 1794 * 1795 * RETURN VALUES: 1796 * 0 - success 1797 * -ENOSPC - insufficient disk resources 1798 * -EIO - i/o error 1799 * 1800 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1801 */ 1802 static int 1803 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results) 1804 { 1805 int rc, nb; 1806 s64 b, lblkno, n; 1807 struct metapage *mp; 1808 struct dmap *dp; 1809 1810 /* check if the allocation request is confined to a single dmap. 1811 */ 1812 if (l2nb <= L2BPERDMAP) { 1813 /* get the buffer for the dmap. 1814 */ 1815 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 1816 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1817 if (mp == NULL) 1818 return -EIO; 1819 dp = (struct dmap *) mp->data; 1820 1821 /* try to allocate the blocks. 1822 */ 1823 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results); 1824 if (rc == 0) 1825 mark_metapage_dirty(mp); 1826 1827 release_metapage(mp); 1828 1829 return (rc); 1830 } 1831 1832 /* allocation request involving multiple dmaps. it must start on 1833 * a dmap boundary. 1834 */ 1835 assert((blkno & (BPERDMAP - 1)) == 0); 1836 1837 /* allocate the blocks dmap by dmap. 1838 */ 1839 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) { 1840 /* get the buffer for the dmap. 1841 */ 1842 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1843 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1844 if (mp == NULL) { 1845 rc = -EIO; 1846 goto backout; 1847 } 1848 dp = (struct dmap *) mp->data; 1849 1850 /* the dmap better be all free. 1851 */ 1852 if (dp->tree.stree[ROOT] != L2BPERDMAP) { 1853 release_metapage(mp); 1854 jfs_error(bmp->db_ipbmap->i_sb, 1855 "the dmap is not all free\n"); 1856 rc = -EIO; 1857 goto backout; 1858 } 1859 1860 /* determine how many blocks to allocate from this dmap. 1861 */ 1862 nb = min_t(s64, n, BPERDMAP); 1863 1864 /* allocate the blocks from the dmap. 1865 */ 1866 if ((rc = dbAllocDmap(bmp, dp, b, nb))) { 1867 release_metapage(mp); 1868 goto backout; 1869 } 1870 1871 /* write the buffer. 1872 */ 1873 write_metapage(mp); 1874 } 1875 1876 /* set the results (starting block number) and return. 1877 */ 1878 *results = blkno; 1879 return (0); 1880 1881 /* something failed in handling an allocation request involving 1882 * multiple dmaps. we'll try to clean up by backing out any 1883 * allocation that has already happened for this request. if 1884 * we fail in backing out the allocation, we'll mark the file 1885 * system to indicate that blocks have been leaked. 1886 */ 1887 backout: 1888 1889 /* try to backout the allocations dmap by dmap. 1890 */ 1891 for (n = nblocks - n, b = blkno; n > 0; 1892 n -= BPERDMAP, b += BPERDMAP) { 1893 /* get the buffer for this dmap. 1894 */ 1895 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1896 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1897 if (mp == NULL) { 1898 /* could not back out. mark the file system 1899 * to indicate that we have leaked blocks. 1900 */ 1901 jfs_error(bmp->db_ipbmap->i_sb, 1902 "I/O Error: Block Leakage\n"); 1903 continue; 1904 } 1905 dp = (struct dmap *) mp->data; 1906 1907 /* free the blocks is this dmap. 1908 */ 1909 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) { 1910 /* could not back out. mark the file system 1911 * to indicate that we have leaked blocks. 1912 */ 1913 release_metapage(mp); 1914 jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n"); 1915 continue; 1916 } 1917 1918 /* write the buffer. 1919 */ 1920 write_metapage(mp); 1921 } 1922 1923 return (rc); 1924 } 1925 1926 1927 /* 1928 * NAME: dbAllocDmapLev() 1929 * 1930 * FUNCTION: attempt to allocate a specified number of contiguous blocks 1931 * from a specified dmap. 1932 * 1933 * this routine checks if the contiguous blocks are available. 1934 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is 1935 * returned. 1936 * 1937 * PARAMETERS: 1938 * mp - pointer to bmap descriptor 1939 * dp - pointer to dmap to attempt to allocate blocks from. 1940 * l2nb - log2 number of contiguous block desired. 1941 * nblocks - actual number of contiguous block desired. 1942 * results - on successful return, set to the starting block number 1943 * of the newly allocated range. 1944 * 1945 * RETURN VALUES: 1946 * 0 - success 1947 * -ENOSPC - insufficient disk resources 1948 * -EIO - i/o error 1949 * 1950 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or 1951 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit; 1952 */ 1953 static int 1954 dbAllocDmapLev(struct bmap * bmp, 1955 struct dmap * dp, int nblocks, int l2nb, s64 * results) 1956 { 1957 s64 blkno; 1958 int leafidx, rc; 1959 1960 /* can't be more than a dmaps worth of blocks */ 1961 assert(l2nb <= L2BPERDMAP); 1962 1963 /* search the tree within the dmap page for sufficient 1964 * free space. if sufficient free space is found, dbFindLeaf() 1965 * returns the index of the leaf at which free space was found. 1966 */ 1967 if (dbFindLeaf((dmtree_t *) &dp->tree, l2nb, &leafidx, false)) 1968 return -ENOSPC; 1969 1970 if (leafidx < 0) 1971 return -EIO; 1972 1973 /* determine the block number within the file system corresponding 1974 * to the leaf at which free space was found. 1975 */ 1976 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD); 1977 1978 /* if not all bits of the dmap word are free, get the starting 1979 * bit number within the dmap word of the required string of free 1980 * bits and adjust the block number with this value. 1981 */ 1982 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN) 1983 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb); 1984 1985 /* allocate the blocks */ 1986 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 1987 *results = blkno; 1988 1989 return (rc); 1990 } 1991 1992 1993 /* 1994 * NAME: dbAllocDmap() 1995 * 1996 * FUNCTION: adjust the disk allocation map to reflect the allocation 1997 * of a specified block range within a dmap. 1998 * 1999 * this routine allocates the specified blocks from the dmap 2000 * through a call to dbAllocBits(). if the allocation of the 2001 * block range causes the maximum string of free blocks within 2002 * the dmap to change (i.e. the value of the root of the dmap's 2003 * dmtree), this routine will cause this change to be reflected 2004 * up through the appropriate levels of the dmap control pages 2005 * by a call to dbAdjCtl() for the L0 dmap control page that 2006 * covers this dmap. 2007 * 2008 * PARAMETERS: 2009 * bmp - pointer to bmap descriptor 2010 * dp - pointer to dmap to allocate the block range from. 2011 * blkno - starting block number of the block to be allocated. 2012 * nblocks - number of blocks to be allocated. 2013 * 2014 * RETURN VALUES: 2015 * 0 - success 2016 * -EIO - i/o error 2017 * 2018 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2019 */ 2020 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2021 int nblocks) 2022 { 2023 s8 oldroot; 2024 int rc; 2025 2026 /* save the current value of the root (i.e. maximum free string) 2027 * of the dmap tree. 2028 */ 2029 oldroot = dp->tree.stree[ROOT]; 2030 2031 /* allocate the specified (blocks) bits */ 2032 dbAllocBits(bmp, dp, blkno, nblocks); 2033 2034 /* if the root has not changed, done. */ 2035 if (dp->tree.stree[ROOT] == oldroot) 2036 return (0); 2037 2038 /* root changed. bubble the change up to the dmap control pages. 2039 * if the adjustment of the upper level control pages fails, 2040 * backout the bit allocation (thus making everything consistent). 2041 */ 2042 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0))) 2043 dbFreeBits(bmp, dp, blkno, nblocks); 2044 2045 return (rc); 2046 } 2047 2048 2049 /* 2050 * NAME: dbFreeDmap() 2051 * 2052 * FUNCTION: adjust the disk allocation map to reflect the allocation 2053 * of a specified block range within a dmap. 2054 * 2055 * this routine frees the specified blocks from the dmap through 2056 * a call to dbFreeBits(). if the deallocation of the block range 2057 * causes the maximum string of free blocks within the dmap to 2058 * change (i.e. the value of the root of the dmap's dmtree), this 2059 * routine will cause this change to be reflected up through the 2060 * appropriate levels of the dmap control pages by a call to 2061 * dbAdjCtl() for the L0 dmap control page that covers this dmap. 2062 * 2063 * PARAMETERS: 2064 * bmp - pointer to bmap descriptor 2065 * dp - pointer to dmap to free the block range from. 2066 * blkno - starting block number of the block to be freed. 2067 * nblocks - number of blocks to be freed. 2068 * 2069 * RETURN VALUES: 2070 * 0 - success 2071 * -EIO - i/o error 2072 * 2073 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2074 */ 2075 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2076 int nblocks) 2077 { 2078 s8 oldroot; 2079 int rc = 0, word; 2080 2081 /* save the current value of the root (i.e. maximum free string) 2082 * of the dmap tree. 2083 */ 2084 oldroot = dp->tree.stree[ROOT]; 2085 2086 /* free the specified (blocks) bits */ 2087 rc = dbFreeBits(bmp, dp, blkno, nblocks); 2088 2089 /* if error or the root has not changed, done. */ 2090 if (rc || (dp->tree.stree[ROOT] == oldroot)) 2091 return (rc); 2092 2093 /* root changed. bubble the change up to the dmap control pages. 2094 * if the adjustment of the upper level control pages fails, 2095 * backout the deallocation. 2096 */ 2097 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) { 2098 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 2099 2100 /* as part of backing out the deallocation, we will have 2101 * to back split the dmap tree if the deallocation caused 2102 * the freed blocks to become part of a larger binary buddy 2103 * system. 2104 */ 2105 if (dp->tree.stree[word] == NOFREE) 2106 dbBackSplit((dmtree_t *) & dp->tree, word); 2107 2108 dbAllocBits(bmp, dp, blkno, nblocks); 2109 } 2110 2111 return (rc); 2112 } 2113 2114 2115 /* 2116 * NAME: dbAllocBits() 2117 * 2118 * FUNCTION: allocate a specified block range from a dmap. 2119 * 2120 * this routine updates the dmap to reflect the working 2121 * state allocation of the specified block range. it directly 2122 * updates the bits of the working map and causes the adjustment 2123 * of the binary buddy system described by the dmap's dmtree 2124 * leaves to reflect the bits allocated. it also causes the 2125 * dmap's dmtree, as a whole, to reflect the allocated range. 2126 * 2127 * PARAMETERS: 2128 * bmp - pointer to bmap descriptor 2129 * dp - pointer to dmap to allocate bits from. 2130 * blkno - starting block number of the bits to be allocated. 2131 * nblocks - number of bits to be allocated. 2132 * 2133 * RETURN VALUES: none 2134 * 2135 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2136 */ 2137 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2138 int nblocks) 2139 { 2140 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2141 dmtree_t *tp = (dmtree_t *) & dp->tree; 2142 int size; 2143 s8 *leaf; 2144 2145 /* pick up a pointer to the leaves of the dmap tree */ 2146 leaf = dp->tree.stree + LEAFIND; 2147 2148 /* determine the bit number and word within the dmap of the 2149 * starting block. 2150 */ 2151 dbitno = blkno & (BPERDMAP - 1); 2152 word = dbitno >> L2DBWORD; 2153 2154 /* block range better be within the dmap */ 2155 assert(dbitno + nblocks <= BPERDMAP); 2156 2157 /* allocate the bits of the dmap's words corresponding to the block 2158 * range. not all bits of the first and last words may be contained 2159 * within the block range. if this is the case, we'll work against 2160 * those words (i.e. partial first and/or last) on an individual basis 2161 * (a single pass), allocating the bits of interest by hand and 2162 * updating the leaf corresponding to the dmap word. a single pass 2163 * will be used for all dmap words fully contained within the 2164 * specified range. within this pass, the bits of all fully contained 2165 * dmap words will be marked as free in a single shot and the leaves 2166 * will be updated. a single leaf may describe the free space of 2167 * multiple dmap words, so we may update only a subset of the actual 2168 * leaves corresponding to the dmap words of the block range. 2169 */ 2170 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2171 /* determine the bit number within the word and 2172 * the number of bits within the word. 2173 */ 2174 wbitno = dbitno & (DBWORD - 1); 2175 nb = min(rembits, DBWORD - wbitno); 2176 2177 /* check if only part of a word is to be allocated. 2178 */ 2179 if (nb < DBWORD) { 2180 /* allocate (set to 1) the appropriate bits within 2181 * this dmap word. 2182 */ 2183 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 2184 >> wbitno); 2185 2186 /* update the leaf for this dmap word. in addition 2187 * to setting the leaf value to the binary buddy max 2188 * of the updated dmap word, dbSplit() will split 2189 * the binary system of the leaves if need be. 2190 */ 2191 dbSplit(tp, word, BUDMIN, 2192 dbMaxBud((u8 *) & dp->wmap[word])); 2193 2194 word += 1; 2195 } else { 2196 /* one or more dmap words are fully contained 2197 * within the block range. determine how many 2198 * words and allocate (set to 1) the bits of these 2199 * words. 2200 */ 2201 nwords = rembits >> L2DBWORD; 2202 memset(&dp->wmap[word], (int) ONES, nwords * 4); 2203 2204 /* determine how many bits. 2205 */ 2206 nb = nwords << L2DBWORD; 2207 2208 /* now update the appropriate leaves to reflect 2209 * the allocated words. 2210 */ 2211 for (; nwords > 0; nwords -= nw) { 2212 if (leaf[word] < BUDMIN) { 2213 jfs_error(bmp->db_ipbmap->i_sb, 2214 "leaf page corrupt\n"); 2215 break; 2216 } 2217 2218 /* determine what the leaf value should be 2219 * updated to as the minimum of the l2 number 2220 * of bits being allocated and the l2 number 2221 * of bits currently described by this leaf. 2222 */ 2223 size = min_t(int, leaf[word], 2224 NLSTOL2BSZ(nwords)); 2225 2226 /* update the leaf to reflect the allocation. 2227 * in addition to setting the leaf value to 2228 * NOFREE, dbSplit() will split the binary 2229 * system of the leaves to reflect the current 2230 * allocation (size). 2231 */ 2232 dbSplit(tp, word, size, NOFREE); 2233 2234 /* get the number of dmap words handled */ 2235 nw = BUDSIZE(size, BUDMIN); 2236 word += nw; 2237 } 2238 } 2239 } 2240 2241 /* update the free count for this dmap */ 2242 le32_add_cpu(&dp->nfree, -nblocks); 2243 2244 BMAP_LOCK(bmp); 2245 2246 /* if this allocation group is completely free, 2247 * update the maximum allocation group number if this allocation 2248 * group is the new max. 2249 */ 2250 agno = blkno >> bmp->db_agl2size; 2251 if (agno > bmp->db_maxag) 2252 bmp->db_maxag = agno; 2253 2254 /* update the free count for the allocation group and map */ 2255 bmp->db_agfree[agno] -= nblocks; 2256 bmp->db_nfree -= nblocks; 2257 2258 BMAP_UNLOCK(bmp); 2259 } 2260 2261 2262 /* 2263 * NAME: dbFreeBits() 2264 * 2265 * FUNCTION: free a specified block range from a dmap. 2266 * 2267 * this routine updates the dmap to reflect the working 2268 * state allocation of the specified block range. it directly 2269 * updates the bits of the working map and causes the adjustment 2270 * of the binary buddy system described by the dmap's dmtree 2271 * leaves to reflect the bits freed. it also causes the dmap's 2272 * dmtree, as a whole, to reflect the deallocated range. 2273 * 2274 * PARAMETERS: 2275 * bmp - pointer to bmap descriptor 2276 * dp - pointer to dmap to free bits from. 2277 * blkno - starting block number of the bits to be freed. 2278 * nblocks - number of bits to be freed. 2279 * 2280 * RETURN VALUES: 0 for success 2281 * 2282 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2283 */ 2284 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2285 int nblocks) 2286 { 2287 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2288 dmtree_t *tp = (dmtree_t *) & dp->tree; 2289 int rc = 0; 2290 int size; 2291 2292 /* determine the bit number and word within the dmap of the 2293 * starting block. 2294 */ 2295 dbitno = blkno & (BPERDMAP - 1); 2296 word = dbitno >> L2DBWORD; 2297 2298 /* block range better be within the dmap. 2299 */ 2300 assert(dbitno + nblocks <= BPERDMAP); 2301 2302 /* free the bits of the dmaps words corresponding to the block range. 2303 * not all bits of the first and last words may be contained within 2304 * the block range. if this is the case, we'll work against those 2305 * words (i.e. partial first and/or last) on an individual basis 2306 * (a single pass), freeing the bits of interest by hand and updating 2307 * the leaf corresponding to the dmap word. a single pass will be used 2308 * for all dmap words fully contained within the specified range. 2309 * within this pass, the bits of all fully contained dmap words will 2310 * be marked as free in a single shot and the leaves will be updated. a 2311 * single leaf may describe the free space of multiple dmap words, 2312 * so we may update only a subset of the actual leaves corresponding 2313 * to the dmap words of the block range. 2314 * 2315 * dbJoin() is used to update leaf values and will join the binary 2316 * buddy system of the leaves if the new leaf values indicate this 2317 * should be done. 2318 */ 2319 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2320 /* determine the bit number within the word and 2321 * the number of bits within the word. 2322 */ 2323 wbitno = dbitno & (DBWORD - 1); 2324 nb = min(rembits, DBWORD - wbitno); 2325 2326 /* check if only part of a word is to be freed. 2327 */ 2328 if (nb < DBWORD) { 2329 /* free (zero) the appropriate bits within this 2330 * dmap word. 2331 */ 2332 dp->wmap[word] &= 2333 cpu_to_le32(~(ONES << (DBWORD - nb) 2334 >> wbitno)); 2335 2336 /* update the leaf for this dmap word. 2337 */ 2338 rc = dbJoin(tp, word, 2339 dbMaxBud((u8 *) & dp->wmap[word])); 2340 if (rc) 2341 return rc; 2342 2343 word += 1; 2344 } else { 2345 /* one or more dmap words are fully contained 2346 * within the block range. determine how many 2347 * words and free (zero) the bits of these words. 2348 */ 2349 nwords = rembits >> L2DBWORD; 2350 memset(&dp->wmap[word], 0, nwords * 4); 2351 2352 /* determine how many bits. 2353 */ 2354 nb = nwords << L2DBWORD; 2355 2356 /* now update the appropriate leaves to reflect 2357 * the freed words. 2358 */ 2359 for (; nwords > 0; nwords -= nw) { 2360 /* determine what the leaf value should be 2361 * updated to as the minimum of the l2 number 2362 * of bits being freed and the l2 (max) number 2363 * of bits that can be described by this leaf. 2364 */ 2365 size = 2366 min(LITOL2BSZ 2367 (word, L2LPERDMAP, BUDMIN), 2368 NLSTOL2BSZ(nwords)); 2369 2370 /* update the leaf. 2371 */ 2372 rc = dbJoin(tp, word, size); 2373 if (rc) 2374 return rc; 2375 2376 /* get the number of dmap words handled. 2377 */ 2378 nw = BUDSIZE(size, BUDMIN); 2379 word += nw; 2380 } 2381 } 2382 } 2383 2384 /* update the free count for this dmap. 2385 */ 2386 le32_add_cpu(&dp->nfree, nblocks); 2387 2388 BMAP_LOCK(bmp); 2389 2390 /* update the free count for the allocation group and 2391 * map. 2392 */ 2393 agno = blkno >> bmp->db_agl2size; 2394 bmp->db_nfree += nblocks; 2395 bmp->db_agfree[agno] += nblocks; 2396 2397 /* check if this allocation group is not completely free and 2398 * if it is currently the maximum (rightmost) allocation group. 2399 * if so, establish the new maximum allocation group number by 2400 * searching left for the first allocation group with allocation. 2401 */ 2402 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) || 2403 (agno == bmp->db_numag - 1 && 2404 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) { 2405 while (bmp->db_maxag > 0) { 2406 bmp->db_maxag -= 1; 2407 if (bmp->db_agfree[bmp->db_maxag] != 2408 bmp->db_agsize) 2409 break; 2410 } 2411 2412 /* re-establish the allocation group preference if the 2413 * current preference is right of the maximum allocation 2414 * group. 2415 */ 2416 if (bmp->db_agpref > bmp->db_maxag) 2417 bmp->db_agpref = bmp->db_maxag; 2418 } 2419 2420 BMAP_UNLOCK(bmp); 2421 2422 return 0; 2423 } 2424 2425 2426 /* 2427 * NAME: dbAdjCtl() 2428 * 2429 * FUNCTION: adjust a dmap control page at a specified level to reflect 2430 * the change in a lower level dmap or dmap control page's 2431 * maximum string of free blocks (i.e. a change in the root 2432 * of the lower level object's dmtree) due to the allocation 2433 * or deallocation of a range of blocks with a single dmap. 2434 * 2435 * on entry, this routine is provided with the new value of 2436 * the lower level dmap or dmap control page root and the 2437 * starting block number of the block range whose allocation 2438 * or deallocation resulted in the root change. this range 2439 * is respresented by a single leaf of the current dmapctl 2440 * and the leaf will be updated with this value, possibly 2441 * causing a binary buddy system within the leaves to be 2442 * split or joined. the update may also cause the dmapctl's 2443 * dmtree to be updated. 2444 * 2445 * if the adjustment of the dmap control page, itself, causes its 2446 * root to change, this change will be bubbled up to the next dmap 2447 * control level by a recursive call to this routine, specifying 2448 * the new root value and the next dmap control page level to 2449 * be adjusted. 2450 * PARAMETERS: 2451 * bmp - pointer to bmap descriptor 2452 * blkno - the first block of a block range within a dmap. it is 2453 * the allocation or deallocation of this block range that 2454 * requires the dmap control page to be adjusted. 2455 * newval - the new value of the lower level dmap or dmap control 2456 * page root. 2457 * alloc - 'true' if adjustment is due to an allocation. 2458 * level - current level of dmap control page (i.e. L0, L1, L2) to 2459 * be adjusted. 2460 * 2461 * RETURN VALUES: 2462 * 0 - success 2463 * -EIO - i/o error 2464 * 2465 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2466 */ 2467 static int 2468 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level) 2469 { 2470 struct metapage *mp; 2471 s8 oldroot; 2472 int oldval; 2473 s64 lblkno; 2474 struct dmapctl *dcp; 2475 int rc, leafno, ti; 2476 2477 /* get the buffer for the dmap control page for the specified 2478 * block number and control page level. 2479 */ 2480 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level); 2481 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 2482 if (mp == NULL) 2483 return -EIO; 2484 dcp = (struct dmapctl *) mp->data; 2485 2486 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 2487 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 2488 release_metapage(mp); 2489 return -EIO; 2490 } 2491 2492 /* determine the leaf number corresponding to the block and 2493 * the index within the dmap control tree. 2494 */ 2495 leafno = BLKTOCTLLEAF(blkno, dcp->budmin); 2496 ti = leafno + le32_to_cpu(dcp->leafidx); 2497 2498 /* save the current leaf value and the current root level (i.e. 2499 * maximum l2 free string described by this dmapctl). 2500 */ 2501 oldval = dcp->stree[ti]; 2502 oldroot = dcp->stree[ROOT]; 2503 2504 /* check if this is a control page update for an allocation. 2505 * if so, update the leaf to reflect the new leaf value using 2506 * dbSplit(); otherwise (deallocation), use dbJoin() to update 2507 * the leaf with the new value. in addition to updating the 2508 * leaf, dbSplit() will also split the binary buddy system of 2509 * the leaves, if required, and bubble new values within the 2510 * dmapctl tree, if required. similarly, dbJoin() will join 2511 * the binary buddy system of leaves and bubble new values up 2512 * the dmapctl tree as required by the new leaf value. 2513 */ 2514 if (alloc) { 2515 /* check if we are in the middle of a binary buddy 2516 * system. this happens when we are performing the 2517 * first allocation out of an allocation group that 2518 * is part (not the first part) of a larger binary 2519 * buddy system. if we are in the middle, back split 2520 * the system prior to calling dbSplit() which assumes 2521 * that it is at the front of a binary buddy system. 2522 */ 2523 if (oldval == NOFREE) { 2524 rc = dbBackSplit((dmtree_t *) dcp, leafno); 2525 if (rc) { 2526 release_metapage(mp); 2527 return rc; 2528 } 2529 oldval = dcp->stree[ti]; 2530 } 2531 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval); 2532 } else { 2533 rc = dbJoin((dmtree_t *) dcp, leafno, newval); 2534 if (rc) { 2535 release_metapage(mp); 2536 return rc; 2537 } 2538 } 2539 2540 /* check if the root of the current dmap control page changed due 2541 * to the update and if the current dmap control page is not at 2542 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e. 2543 * root changed and this is not the top level), call this routine 2544 * again (recursion) for the next higher level of the mapping to 2545 * reflect the change in root for the current dmap control page. 2546 */ 2547 if (dcp->stree[ROOT] != oldroot) { 2548 /* are we below the top level of the map. if so, 2549 * bubble the root up to the next higher level. 2550 */ 2551 if (level < bmp->db_maxlevel) { 2552 /* bubble up the new root of this dmap control page to 2553 * the next level. 2554 */ 2555 if ((rc = 2556 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc, 2557 level + 1))) { 2558 /* something went wrong in bubbling up the new 2559 * root value, so backout the changes to the 2560 * current dmap control page. 2561 */ 2562 if (alloc) { 2563 dbJoin((dmtree_t *) dcp, leafno, 2564 oldval); 2565 } else { 2566 /* the dbJoin() above might have 2567 * caused a larger binary buddy system 2568 * to form and we may now be in the 2569 * middle of it. if this is the case, 2570 * back split the buddies. 2571 */ 2572 if (dcp->stree[ti] == NOFREE) 2573 dbBackSplit((dmtree_t *) 2574 dcp, leafno); 2575 dbSplit((dmtree_t *) dcp, leafno, 2576 dcp->budmin, oldval); 2577 } 2578 2579 /* release the buffer and return the error. 2580 */ 2581 release_metapage(mp); 2582 return (rc); 2583 } 2584 } else { 2585 /* we're at the top level of the map. update 2586 * the bmap control page to reflect the size 2587 * of the maximum free buddy system. 2588 */ 2589 assert(level == bmp->db_maxlevel); 2590 if (bmp->db_maxfreebud != oldroot) { 2591 jfs_error(bmp->db_ipbmap->i_sb, 2592 "the maximum free buddy is not the old root\n"); 2593 } 2594 bmp->db_maxfreebud = dcp->stree[ROOT]; 2595 } 2596 } 2597 2598 /* write the buffer. 2599 */ 2600 write_metapage(mp); 2601 2602 return (0); 2603 } 2604 2605 2606 /* 2607 * NAME: dbSplit() 2608 * 2609 * FUNCTION: update the leaf of a dmtree with a new value, splitting 2610 * the leaf from the binary buddy system of the dmtree's 2611 * leaves, as required. 2612 * 2613 * PARAMETERS: 2614 * tp - pointer to the tree containing the leaf. 2615 * leafno - the number of the leaf to be updated. 2616 * splitsz - the size the binary buddy system starting at the leaf 2617 * must be split to, specified as the log2 number of blocks. 2618 * newval - the new value for the leaf. 2619 * 2620 * RETURN VALUES: none 2621 * 2622 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2623 */ 2624 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval) 2625 { 2626 int budsz; 2627 int cursz; 2628 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2629 2630 /* check if the leaf needs to be split. 2631 */ 2632 if (leaf[leafno] > tp->dmt_budmin) { 2633 /* the split occurs by cutting the buddy system in half 2634 * at the specified leaf until we reach the specified 2635 * size. pick up the starting split size (current size 2636 * - 1 in l2) and the corresponding buddy size. 2637 */ 2638 cursz = leaf[leafno] - 1; 2639 budsz = BUDSIZE(cursz, tp->dmt_budmin); 2640 2641 /* split until we reach the specified size. 2642 */ 2643 while (cursz >= splitsz) { 2644 /* update the buddy's leaf with its new value. 2645 */ 2646 dbAdjTree(tp, leafno ^ budsz, cursz); 2647 2648 /* on to the next size and buddy. 2649 */ 2650 cursz -= 1; 2651 budsz >>= 1; 2652 } 2653 } 2654 2655 /* adjust the dmap tree to reflect the specified leaf's new 2656 * value. 2657 */ 2658 dbAdjTree(tp, leafno, newval); 2659 } 2660 2661 2662 /* 2663 * NAME: dbBackSplit() 2664 * 2665 * FUNCTION: back split the binary buddy system of dmtree leaves 2666 * that hold a specified leaf until the specified leaf 2667 * starts its own binary buddy system. 2668 * 2669 * the allocators typically perform allocations at the start 2670 * of binary buddy systems and dbSplit() is used to accomplish 2671 * any required splits. in some cases, however, allocation 2672 * may occur in the middle of a binary system and requires a 2673 * back split, with the split proceeding out from the middle of 2674 * the system (less efficient) rather than the start of the 2675 * system (more efficient). the cases in which a back split 2676 * is required are rare and are limited to the first allocation 2677 * within an allocation group which is a part (not first part) 2678 * of a larger binary buddy system and a few exception cases 2679 * in which a previous join operation must be backed out. 2680 * 2681 * PARAMETERS: 2682 * tp - pointer to the tree containing the leaf. 2683 * leafno - the number of the leaf to be updated. 2684 * 2685 * RETURN VALUES: none 2686 * 2687 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2688 */ 2689 static int dbBackSplit(dmtree_t * tp, int leafno) 2690 { 2691 int budsz, bud, w, bsz, size; 2692 int cursz; 2693 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2694 2695 /* leaf should be part (not first part) of a binary 2696 * buddy system. 2697 */ 2698 assert(leaf[leafno] == NOFREE); 2699 2700 /* the back split is accomplished by iteratively finding the leaf 2701 * that starts the buddy system that contains the specified leaf and 2702 * splitting that system in two. this iteration continues until 2703 * the specified leaf becomes the start of a buddy system. 2704 * 2705 * determine maximum possible l2 size for the specified leaf. 2706 */ 2707 size = 2708 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs), 2709 tp->dmt_budmin); 2710 2711 /* determine the number of leaves covered by this size. this 2712 * is the buddy size that we will start with as we search for 2713 * the buddy system that contains the specified leaf. 2714 */ 2715 budsz = BUDSIZE(size, tp->dmt_budmin); 2716 2717 /* back split. 2718 */ 2719 while (leaf[leafno] == NOFREE) { 2720 /* find the leftmost buddy leaf. 2721 */ 2722 for (w = leafno, bsz = budsz;; bsz <<= 1, 2723 w = (w < bud) ? w : bud) { 2724 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) { 2725 jfs_err("JFS: block map error in dbBackSplit"); 2726 return -EIO; 2727 } 2728 2729 /* determine the buddy. 2730 */ 2731 bud = w ^ bsz; 2732 2733 /* check if this buddy is the start of the system. 2734 */ 2735 if (leaf[bud] != NOFREE) { 2736 /* split the leaf at the start of the 2737 * system in two. 2738 */ 2739 cursz = leaf[bud] - 1; 2740 dbSplit(tp, bud, cursz, cursz); 2741 break; 2742 } 2743 } 2744 } 2745 2746 if (leaf[leafno] != size) { 2747 jfs_err("JFS: wrong leaf value in dbBackSplit"); 2748 return -EIO; 2749 } 2750 return 0; 2751 } 2752 2753 2754 /* 2755 * NAME: dbJoin() 2756 * 2757 * FUNCTION: update the leaf of a dmtree with a new value, joining 2758 * the leaf with other leaves of the dmtree into a multi-leaf 2759 * binary buddy system, as required. 2760 * 2761 * PARAMETERS: 2762 * tp - pointer to the tree containing the leaf. 2763 * leafno - the number of the leaf to be updated. 2764 * newval - the new value for the leaf. 2765 * 2766 * RETURN VALUES: none 2767 */ 2768 static int dbJoin(dmtree_t * tp, int leafno, int newval) 2769 { 2770 int budsz, buddy; 2771 s8 *leaf; 2772 2773 /* can the new leaf value require a join with other leaves ? 2774 */ 2775 if (newval >= tp->dmt_budmin) { 2776 /* pickup a pointer to the leaves of the tree. 2777 */ 2778 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2779 2780 /* try to join the specified leaf into a large binary 2781 * buddy system. the join proceeds by attempting to join 2782 * the specified leafno with its buddy (leaf) at new value. 2783 * if the join occurs, we attempt to join the left leaf 2784 * of the joined buddies with its buddy at new value + 1. 2785 * we continue to join until we find a buddy that cannot be 2786 * joined (does not have a value equal to the size of the 2787 * last join) or until all leaves have been joined into a 2788 * single system. 2789 * 2790 * get the buddy size (number of words covered) of 2791 * the new value. 2792 */ 2793 budsz = BUDSIZE(newval, tp->dmt_budmin); 2794 2795 /* try to join. 2796 */ 2797 while (budsz < le32_to_cpu(tp->dmt_nleafs)) { 2798 /* get the buddy leaf. 2799 */ 2800 buddy = leafno ^ budsz; 2801 2802 /* if the leaf's new value is greater than its 2803 * buddy's value, we join no more. 2804 */ 2805 if (newval > leaf[buddy]) 2806 break; 2807 2808 /* It shouldn't be less */ 2809 if (newval < leaf[buddy]) 2810 return -EIO; 2811 2812 /* check which (leafno or buddy) is the left buddy. 2813 * the left buddy gets to claim the blocks resulting 2814 * from the join while the right gets to claim none. 2815 * the left buddy is also eligible to participate in 2816 * a join at the next higher level while the right 2817 * is not. 2818 * 2819 */ 2820 if (leafno < buddy) { 2821 /* leafno is the left buddy. 2822 */ 2823 dbAdjTree(tp, buddy, NOFREE); 2824 } else { 2825 /* buddy is the left buddy and becomes 2826 * leafno. 2827 */ 2828 dbAdjTree(tp, leafno, NOFREE); 2829 leafno = buddy; 2830 } 2831 2832 /* on to try the next join. 2833 */ 2834 newval += 1; 2835 budsz <<= 1; 2836 } 2837 } 2838 2839 /* update the leaf value. 2840 */ 2841 dbAdjTree(tp, leafno, newval); 2842 2843 return 0; 2844 } 2845 2846 2847 /* 2848 * NAME: dbAdjTree() 2849 * 2850 * FUNCTION: update a leaf of a dmtree with a new value, adjusting 2851 * the dmtree, as required, to reflect the new leaf value. 2852 * the combination of any buddies must already be done before 2853 * this is called. 2854 * 2855 * PARAMETERS: 2856 * tp - pointer to the tree to be adjusted. 2857 * leafno - the number of the leaf to be updated. 2858 * newval - the new value for the leaf. 2859 * 2860 * RETURN VALUES: none 2861 */ 2862 static void dbAdjTree(dmtree_t * tp, int leafno, int newval) 2863 { 2864 int lp, pp, k; 2865 int max; 2866 2867 /* pick up the index of the leaf for this leafno. 2868 */ 2869 lp = leafno + le32_to_cpu(tp->dmt_leafidx); 2870 2871 /* is the current value the same as the old value ? if so, 2872 * there is nothing to do. 2873 */ 2874 if (tp->dmt_stree[lp] == newval) 2875 return; 2876 2877 /* set the new value. 2878 */ 2879 tp->dmt_stree[lp] = newval; 2880 2881 /* bubble the new value up the tree as required. 2882 */ 2883 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) { 2884 /* get the index of the first leaf of the 4 leaf 2885 * group containing the specified leaf (leafno). 2886 */ 2887 lp = ((lp - 1) & ~0x03) + 1; 2888 2889 /* get the index of the parent of this 4 leaf group. 2890 */ 2891 pp = (lp - 1) >> 2; 2892 2893 /* determine the maximum of the 4 leaves. 2894 */ 2895 max = TREEMAX(&tp->dmt_stree[lp]); 2896 2897 /* if the maximum of the 4 is the same as the 2898 * parent's value, we're done. 2899 */ 2900 if (tp->dmt_stree[pp] == max) 2901 break; 2902 2903 /* parent gets new value. 2904 */ 2905 tp->dmt_stree[pp] = max; 2906 2907 /* parent becomes leaf for next go-round. 2908 */ 2909 lp = pp; 2910 } 2911 } 2912 2913 2914 /* 2915 * NAME: dbFindLeaf() 2916 * 2917 * FUNCTION: search a dmtree_t for sufficient free blocks, returning 2918 * the index of a leaf describing the free blocks if 2919 * sufficient free blocks are found. 2920 * 2921 * the search starts at the top of the dmtree_t tree and 2922 * proceeds down the tree to the leftmost leaf with sufficient 2923 * free space. 2924 * 2925 * PARAMETERS: 2926 * tp - pointer to the tree to be searched. 2927 * l2nb - log2 number of free blocks to search for. 2928 * leafidx - return pointer to be set to the index of the leaf 2929 * describing at least l2nb free blocks if sufficient 2930 * free blocks are found. 2931 * is_ctl - determines if the tree is of type ctl 2932 * 2933 * RETURN VALUES: 2934 * 0 - success 2935 * -ENOSPC - insufficient free blocks. 2936 */ 2937 static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl) 2938 { 2939 int ti, n = 0, k, x = 0; 2940 int max_size; 2941 2942 max_size = is_ctl ? CTLTREESIZE : TREESIZE; 2943 2944 /* first check the root of the tree to see if there is 2945 * sufficient free space. 2946 */ 2947 if (l2nb > tp->dmt_stree[ROOT]) 2948 return -ENOSPC; 2949 2950 /* sufficient free space available. now search down the tree 2951 * starting at the next level for the leftmost leaf that 2952 * describes sufficient free space. 2953 */ 2954 for (k = le32_to_cpu(tp->dmt_height), ti = 1; 2955 k > 0; k--, ti = ((ti + n) << 2) + 1) { 2956 /* search the four nodes at this level, starting from 2957 * the left. 2958 */ 2959 for (x = ti, n = 0; n < 4; n++) { 2960 /* sufficient free space found. move to the next 2961 * level (or quit if this is the last level). 2962 */ 2963 if (x + n > max_size) 2964 return -ENOSPC; 2965 if (l2nb <= tp->dmt_stree[x + n]) 2966 break; 2967 } 2968 2969 /* better have found something since the higher 2970 * levels of the tree said it was here. 2971 */ 2972 assert(n < 4); 2973 } 2974 2975 /* set the return to the leftmost leaf describing sufficient 2976 * free space. 2977 */ 2978 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx); 2979 2980 return (0); 2981 } 2982 2983 2984 /* 2985 * NAME: dbFindBits() 2986 * 2987 * FUNCTION: find a specified number of binary buddy free bits within a 2988 * dmap bitmap word value. 2989 * 2990 * this routine searches the bitmap value for (1 << l2nb) free 2991 * bits at (1 << l2nb) alignments within the value. 2992 * 2993 * PARAMETERS: 2994 * word - dmap bitmap word value. 2995 * l2nb - number of free bits specified as a log2 number. 2996 * 2997 * RETURN VALUES: 2998 * starting bit number of free bits. 2999 */ 3000 static int dbFindBits(u32 word, int l2nb) 3001 { 3002 int bitno, nb; 3003 u32 mask; 3004 3005 /* get the number of bits. 3006 */ 3007 nb = 1 << l2nb; 3008 assert(nb <= DBWORD); 3009 3010 /* complement the word so we can use a mask (i.e. 0s represent 3011 * free bits) and compute the mask. 3012 */ 3013 word = ~word; 3014 mask = ONES << (DBWORD - nb); 3015 3016 /* scan the word for nb free bits at nb alignments. 3017 */ 3018 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) { 3019 if ((mask & word) == mask) 3020 break; 3021 } 3022 3023 ASSERT(bitno < 32); 3024 3025 /* return the bit number. 3026 */ 3027 return (bitno); 3028 } 3029 3030 3031 /* 3032 * NAME: dbMaxBud(u8 *cp) 3033 * 3034 * FUNCTION: determine the largest binary buddy string of free 3035 * bits within 32-bits of the map. 3036 * 3037 * PARAMETERS: 3038 * cp - pointer to the 32-bit value. 3039 * 3040 * RETURN VALUES: 3041 * largest binary buddy of free bits within a dmap word. 3042 */ 3043 static int dbMaxBud(u8 * cp) 3044 { 3045 signed char tmp1, tmp2; 3046 3047 /* check if the wmap word is all free. if so, the 3048 * free buddy size is BUDMIN. 3049 */ 3050 if (*((uint *) cp) == 0) 3051 return (BUDMIN); 3052 3053 /* check if the wmap word is half free. if so, the 3054 * free buddy size is BUDMIN-1. 3055 */ 3056 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0) 3057 return (BUDMIN - 1); 3058 3059 /* not all free or half free. determine the free buddy 3060 * size thru table lookup using quarters of the wmap word. 3061 */ 3062 tmp1 = max(budtab[cp[2]], budtab[cp[3]]); 3063 tmp2 = max(budtab[cp[0]], budtab[cp[1]]); 3064 return (max(tmp1, tmp2)); 3065 } 3066 3067 3068 /* 3069 * NAME: cnttz(uint word) 3070 * 3071 * FUNCTION: determine the number of trailing zeros within a 32-bit 3072 * value. 3073 * 3074 * PARAMETERS: 3075 * value - 32-bit value to be examined. 3076 * 3077 * RETURN VALUES: 3078 * count of trailing zeros 3079 */ 3080 static int cnttz(u32 word) 3081 { 3082 int n; 3083 3084 for (n = 0; n < 32; n++, word >>= 1) { 3085 if (word & 0x01) 3086 break; 3087 } 3088 3089 return (n); 3090 } 3091 3092 3093 /* 3094 * NAME: cntlz(u32 value) 3095 * 3096 * FUNCTION: determine the number of leading zeros within a 32-bit 3097 * value. 3098 * 3099 * PARAMETERS: 3100 * value - 32-bit value to be examined. 3101 * 3102 * RETURN VALUES: 3103 * count of leading zeros 3104 */ 3105 static int cntlz(u32 value) 3106 { 3107 int n; 3108 3109 for (n = 0; n < 32; n++, value <<= 1) { 3110 if (value & HIGHORDER) 3111 break; 3112 } 3113 return (n); 3114 } 3115 3116 3117 /* 3118 * NAME: blkstol2(s64 nb) 3119 * 3120 * FUNCTION: convert a block count to its log2 value. if the block 3121 * count is not a l2 multiple, it is rounded up to the next 3122 * larger l2 multiple. 3123 * 3124 * PARAMETERS: 3125 * nb - number of blocks 3126 * 3127 * RETURN VALUES: 3128 * log2 number of blocks 3129 */ 3130 static int blkstol2(s64 nb) 3131 { 3132 int l2nb; 3133 s64 mask; /* meant to be signed */ 3134 3135 mask = (s64) 1 << (64 - 1); 3136 3137 /* count the leading bits. 3138 */ 3139 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) { 3140 /* leading bit found. 3141 */ 3142 if (nb & mask) { 3143 /* determine the l2 value. 3144 */ 3145 l2nb = (64 - 1) - l2nb; 3146 3147 /* check if we need to round up. 3148 */ 3149 if (~mask & nb) 3150 l2nb++; 3151 3152 return (l2nb); 3153 } 3154 } 3155 assert(0); 3156 return 0; /* fix compiler warning */ 3157 } 3158 3159 3160 /* 3161 * NAME: dbAllocBottomUp() 3162 * 3163 * FUNCTION: alloc the specified block range from the working block 3164 * allocation map. 3165 * 3166 * the blocks will be alloc from the working map one dmap 3167 * at a time. 3168 * 3169 * PARAMETERS: 3170 * ip - pointer to in-core inode; 3171 * blkno - starting block number to be freed. 3172 * nblocks - number of blocks to be freed. 3173 * 3174 * RETURN VALUES: 3175 * 0 - success 3176 * -EIO - i/o error 3177 */ 3178 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks) 3179 { 3180 struct metapage *mp; 3181 struct dmap *dp; 3182 int nb, rc; 3183 s64 lblkno, rem; 3184 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 3185 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 3186 3187 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 3188 3189 /* block to be allocated better be within the mapsize. */ 3190 ASSERT(nblocks <= bmp->db_mapsize - blkno); 3191 3192 /* 3193 * allocate the blocks a dmap at a time. 3194 */ 3195 mp = NULL; 3196 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 3197 /* release previous dmap if any */ 3198 if (mp) { 3199 write_metapage(mp); 3200 } 3201 3202 /* get the buffer for the current dmap. */ 3203 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 3204 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 3205 if (mp == NULL) { 3206 IREAD_UNLOCK(ipbmap); 3207 return -EIO; 3208 } 3209 dp = (struct dmap *) mp->data; 3210 3211 /* determine the number of blocks to be allocated from 3212 * this dmap. 3213 */ 3214 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 3215 3216 /* allocate the blocks. */ 3217 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) { 3218 release_metapage(mp); 3219 IREAD_UNLOCK(ipbmap); 3220 return (rc); 3221 } 3222 } 3223 3224 /* write the last buffer. */ 3225 write_metapage(mp); 3226 3227 IREAD_UNLOCK(ipbmap); 3228 3229 return (0); 3230 } 3231 3232 3233 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 3234 int nblocks) 3235 { 3236 int rc; 3237 int dbitno, word, rembits, nb, nwords, wbitno, agno; 3238 s8 oldroot; 3239 struct dmaptree *tp = (struct dmaptree *) & dp->tree; 3240 3241 /* save the current value of the root (i.e. maximum free string) 3242 * of the dmap tree. 3243 */ 3244 oldroot = tp->stree[ROOT]; 3245 3246 /* determine the bit number and word within the dmap of the 3247 * starting block. 3248 */ 3249 dbitno = blkno & (BPERDMAP - 1); 3250 word = dbitno >> L2DBWORD; 3251 3252 /* block range better be within the dmap */ 3253 assert(dbitno + nblocks <= BPERDMAP); 3254 3255 /* allocate the bits of the dmap's words corresponding to the block 3256 * range. not all bits of the first and last words may be contained 3257 * within the block range. if this is the case, we'll work against 3258 * those words (i.e. partial first and/or last) on an individual basis 3259 * (a single pass), allocating the bits of interest by hand and 3260 * updating the leaf corresponding to the dmap word. a single pass 3261 * will be used for all dmap words fully contained within the 3262 * specified range. within this pass, the bits of all fully contained 3263 * dmap words will be marked as free in a single shot and the leaves 3264 * will be updated. a single leaf may describe the free space of 3265 * multiple dmap words, so we may update only a subset of the actual 3266 * leaves corresponding to the dmap words of the block range. 3267 */ 3268 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 3269 /* determine the bit number within the word and 3270 * the number of bits within the word. 3271 */ 3272 wbitno = dbitno & (DBWORD - 1); 3273 nb = min(rembits, DBWORD - wbitno); 3274 3275 /* check if only part of a word is to be allocated. 3276 */ 3277 if (nb < DBWORD) { 3278 /* allocate (set to 1) the appropriate bits within 3279 * this dmap word. 3280 */ 3281 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 3282 >> wbitno); 3283 3284 word++; 3285 } else { 3286 /* one or more dmap words are fully contained 3287 * within the block range. determine how many 3288 * words and allocate (set to 1) the bits of these 3289 * words. 3290 */ 3291 nwords = rembits >> L2DBWORD; 3292 memset(&dp->wmap[word], (int) ONES, nwords * 4); 3293 3294 /* determine how many bits */ 3295 nb = nwords << L2DBWORD; 3296 word += nwords; 3297 } 3298 } 3299 3300 /* update the free count for this dmap */ 3301 le32_add_cpu(&dp->nfree, -nblocks); 3302 3303 /* reconstruct summary tree */ 3304 dbInitDmapTree(dp); 3305 3306 BMAP_LOCK(bmp); 3307 3308 /* if this allocation group is completely free, 3309 * update the highest active allocation group number 3310 * if this allocation group is the new max. 3311 */ 3312 agno = blkno >> bmp->db_agl2size; 3313 if (agno > bmp->db_maxag) 3314 bmp->db_maxag = agno; 3315 3316 /* update the free count for the allocation group and map */ 3317 bmp->db_agfree[agno] -= nblocks; 3318 bmp->db_nfree -= nblocks; 3319 3320 BMAP_UNLOCK(bmp); 3321 3322 /* if the root has not changed, done. */ 3323 if (tp->stree[ROOT] == oldroot) 3324 return (0); 3325 3326 /* root changed. bubble the change up to the dmap control pages. 3327 * if the adjustment of the upper level control pages fails, 3328 * backout the bit allocation (thus making everything consistent). 3329 */ 3330 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0))) 3331 dbFreeBits(bmp, dp, blkno, nblocks); 3332 3333 return (rc); 3334 } 3335 3336 3337 /* 3338 * NAME: dbExtendFS() 3339 * 3340 * FUNCTION: extend bmap from blkno for nblocks; 3341 * dbExtendFS() updates bmap ready for dbAllocBottomUp(); 3342 * 3343 * L2 3344 * | 3345 * L1---------------------------------L1 3346 * | | 3347 * L0---------L0---------L0 L0---------L0---------L0 3348 * | | | | | | 3349 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm; 3350 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm 3351 * 3352 * <---old---><----------------------------extend-----------------------> 3353 */ 3354 int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks) 3355 { 3356 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb); 3357 int nbperpage = sbi->nbperpage; 3358 int i, i0 = true, j, j0 = true, k, n; 3359 s64 newsize; 3360 s64 p; 3361 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL; 3362 struct dmapctl *l2dcp, *l1dcp, *l0dcp; 3363 struct dmap *dp; 3364 s8 *l0leaf, *l1leaf, *l2leaf; 3365 struct bmap *bmp = sbi->bmap; 3366 int agno, l2agsize, oldl2agsize; 3367 s64 ag_rem; 3368 3369 newsize = blkno + nblocks; 3370 3371 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld", 3372 (long long) blkno, (long long) nblocks, (long long) newsize); 3373 3374 /* 3375 * initialize bmap control page. 3376 * 3377 * all the data in bmap control page should exclude 3378 * the mkfs hidden dmap page. 3379 */ 3380 3381 /* update mapsize */ 3382 bmp->db_mapsize = newsize; 3383 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize); 3384 3385 /* compute new AG size */ 3386 l2agsize = dbGetL2AGSize(newsize); 3387 oldl2agsize = bmp->db_agl2size; 3388 3389 bmp->db_agl2size = l2agsize; 3390 bmp->db_agsize = 1 << l2agsize; 3391 3392 /* compute new number of AG */ 3393 agno = bmp->db_numag; 3394 bmp->db_numag = newsize >> l2agsize; 3395 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0; 3396 3397 /* 3398 * reconfigure db_agfree[] 3399 * from old AG configuration to new AG configuration; 3400 * 3401 * coalesce contiguous k (newAGSize/oldAGSize) AGs; 3402 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn; 3403 * note: new AG size = old AG size * (2**x). 3404 */ 3405 if (l2agsize == oldl2agsize) 3406 goto extend; 3407 k = 1 << (l2agsize - oldl2agsize); 3408 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */ 3409 for (i = 0, n = 0; i < agno; n++) { 3410 bmp->db_agfree[n] = 0; /* init collection point */ 3411 3412 /* coalesce contiguous k AGs; */ 3413 for (j = 0; j < k && i < agno; j++, i++) { 3414 /* merge AGi to AGn */ 3415 bmp->db_agfree[n] += bmp->db_agfree[i]; 3416 } 3417 } 3418 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */ 3419 3420 for (; n < MAXAG; n++) 3421 bmp->db_agfree[n] = 0; 3422 3423 /* 3424 * update highest active ag number 3425 */ 3426 3427 bmp->db_maxag = bmp->db_maxag / k; 3428 3429 /* 3430 * extend bmap 3431 * 3432 * update bit maps and corresponding level control pages; 3433 * global control page db_nfree, db_agfree[agno], db_maxfreebud; 3434 */ 3435 extend: 3436 /* get L2 page */ 3437 p = BMAPBLKNO + nbperpage; /* L2 page */ 3438 l2mp = read_metapage(ipbmap, p, PSIZE, 0); 3439 if (!l2mp) { 3440 jfs_error(ipbmap->i_sb, "L2 page could not be read\n"); 3441 return -EIO; 3442 } 3443 l2dcp = (struct dmapctl *) l2mp->data; 3444 3445 /* compute start L1 */ 3446 k = blkno >> L2MAXL1SIZE; 3447 l2leaf = l2dcp->stree + CTLLEAFIND + k; 3448 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */ 3449 3450 /* 3451 * extend each L1 in L2 3452 */ 3453 for (; k < LPERCTL; k++, p += nbperpage) { 3454 /* get L1 page */ 3455 if (j0) { 3456 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */ 3457 l1mp = read_metapage(ipbmap, p, PSIZE, 0); 3458 if (l1mp == NULL) 3459 goto errout; 3460 l1dcp = (struct dmapctl *) l1mp->data; 3461 3462 /* compute start L0 */ 3463 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE; 3464 l1leaf = l1dcp->stree + CTLLEAFIND + j; 3465 p = BLKTOL0(blkno, sbi->l2nbperpage); 3466 j0 = false; 3467 } else { 3468 /* assign/init L1 page */ 3469 l1mp = get_metapage(ipbmap, p, PSIZE, 0); 3470 if (l1mp == NULL) 3471 goto errout; 3472 3473 l1dcp = (struct dmapctl *) l1mp->data; 3474 3475 /* compute start L0 */ 3476 j = 0; 3477 l1leaf = l1dcp->stree + CTLLEAFIND; 3478 p += nbperpage; /* 1st L0 of L1.k */ 3479 } 3480 3481 /* 3482 * extend each L0 in L1 3483 */ 3484 for (; j < LPERCTL; j++) { 3485 /* get L0 page */ 3486 if (i0) { 3487 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */ 3488 3489 l0mp = read_metapage(ipbmap, p, PSIZE, 0); 3490 if (l0mp == NULL) 3491 goto errout; 3492 l0dcp = (struct dmapctl *) l0mp->data; 3493 3494 /* compute start dmap */ 3495 i = (blkno & (MAXL0SIZE - 1)) >> 3496 L2BPERDMAP; 3497 l0leaf = l0dcp->stree + CTLLEAFIND + i; 3498 p = BLKTODMAP(blkno, 3499 sbi->l2nbperpage); 3500 i0 = false; 3501 } else { 3502 /* assign/init L0 page */ 3503 l0mp = get_metapage(ipbmap, p, PSIZE, 0); 3504 if (l0mp == NULL) 3505 goto errout; 3506 3507 l0dcp = (struct dmapctl *) l0mp->data; 3508 3509 /* compute start dmap */ 3510 i = 0; 3511 l0leaf = l0dcp->stree + CTLLEAFIND; 3512 p += nbperpage; /* 1st dmap of L0.j */ 3513 } 3514 3515 /* 3516 * extend each dmap in L0 3517 */ 3518 for (; i < LPERCTL; i++) { 3519 /* 3520 * reconstruct the dmap page, and 3521 * initialize corresponding parent L0 leaf 3522 */ 3523 if ((n = blkno & (BPERDMAP - 1))) { 3524 /* read in dmap page: */ 3525 mp = read_metapage(ipbmap, p, 3526 PSIZE, 0); 3527 if (mp == NULL) 3528 goto errout; 3529 n = min(nblocks, (s64)BPERDMAP - n); 3530 } else { 3531 /* assign/init dmap page */ 3532 mp = read_metapage(ipbmap, p, 3533 PSIZE, 0); 3534 if (mp == NULL) 3535 goto errout; 3536 3537 n = min_t(s64, nblocks, BPERDMAP); 3538 } 3539 3540 dp = (struct dmap *) mp->data; 3541 *l0leaf = dbInitDmap(dp, blkno, n); 3542 3543 bmp->db_nfree += n; 3544 agno = le64_to_cpu(dp->start) >> l2agsize; 3545 bmp->db_agfree[agno] += n; 3546 3547 write_metapage(mp); 3548 3549 l0leaf++; 3550 p += nbperpage; 3551 3552 blkno += n; 3553 nblocks -= n; 3554 if (nblocks == 0) 3555 break; 3556 } /* for each dmap in a L0 */ 3557 3558 /* 3559 * build current L0 page from its leaves, and 3560 * initialize corresponding parent L1 leaf 3561 */ 3562 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i); 3563 write_metapage(l0mp); 3564 l0mp = NULL; 3565 3566 if (nblocks) 3567 l1leaf++; /* continue for next L0 */ 3568 else { 3569 /* more than 1 L0 ? */ 3570 if (j > 0) 3571 break; /* build L1 page */ 3572 else { 3573 /* summarize in global bmap page */ 3574 bmp->db_maxfreebud = *l1leaf; 3575 release_metapage(l1mp); 3576 release_metapage(l2mp); 3577 goto finalize; 3578 } 3579 } 3580 } /* for each L0 in a L1 */ 3581 3582 /* 3583 * build current L1 page from its leaves, and 3584 * initialize corresponding parent L2 leaf 3585 */ 3586 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j); 3587 write_metapage(l1mp); 3588 l1mp = NULL; 3589 3590 if (nblocks) 3591 l2leaf++; /* continue for next L1 */ 3592 else { 3593 /* more than 1 L1 ? */ 3594 if (k > 0) 3595 break; /* build L2 page */ 3596 else { 3597 /* summarize in global bmap page */ 3598 bmp->db_maxfreebud = *l2leaf; 3599 release_metapage(l2mp); 3600 goto finalize; 3601 } 3602 } 3603 } /* for each L1 in a L2 */ 3604 3605 jfs_error(ipbmap->i_sb, "function has not returned as expected\n"); 3606 errout: 3607 if (l0mp) 3608 release_metapage(l0mp); 3609 if (l1mp) 3610 release_metapage(l1mp); 3611 release_metapage(l2mp); 3612 return -EIO; 3613 3614 /* 3615 * finalize bmap control page 3616 */ 3617 finalize: 3618 3619 return 0; 3620 } 3621 3622 3623 /* 3624 * dbFinalizeBmap() 3625 */ 3626 void dbFinalizeBmap(struct inode *ipbmap) 3627 { 3628 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 3629 int actags, inactags, l2nl; 3630 s64 ag_rem, actfree, inactfree, avgfree; 3631 int i, n; 3632 3633 /* 3634 * finalize bmap control page 3635 */ 3636 //finalize: 3637 /* 3638 * compute db_agpref: preferred ag to allocate from 3639 * (the leftmost ag with average free space in it); 3640 */ 3641 //agpref: 3642 /* get the number of active ags and inactive ags */ 3643 actags = bmp->db_maxag + 1; 3644 inactags = bmp->db_numag - actags; 3645 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */ 3646 3647 /* determine how many blocks are in the inactive allocation 3648 * groups. in doing this, we must account for the fact that 3649 * the rightmost group might be a partial group (i.e. file 3650 * system size is not a multiple of the group size). 3651 */ 3652 inactfree = (inactags && ag_rem) ? 3653 ((inactags - 1) << bmp->db_agl2size) + ag_rem 3654 : inactags << bmp->db_agl2size; 3655 3656 /* determine how many free blocks are in the active 3657 * allocation groups plus the average number of free blocks 3658 * within the active ags. 3659 */ 3660 actfree = bmp->db_nfree - inactfree; 3661 avgfree = (u32) actfree / (u32) actags; 3662 3663 /* if the preferred allocation group has not average free space. 3664 * re-establish the preferred group as the leftmost 3665 * group with average free space. 3666 */ 3667 if (bmp->db_agfree[bmp->db_agpref] < avgfree) { 3668 for (bmp->db_agpref = 0; bmp->db_agpref < actags; 3669 bmp->db_agpref++) { 3670 if (bmp->db_agfree[bmp->db_agpref] >= avgfree) 3671 break; 3672 } 3673 if (bmp->db_agpref >= bmp->db_numag) { 3674 jfs_error(ipbmap->i_sb, 3675 "cannot find ag with average freespace\n"); 3676 } 3677 } 3678 3679 /* 3680 * compute db_aglevel, db_agheight, db_width, db_agstart: 3681 * an ag is covered in aglevel dmapctl summary tree, 3682 * at agheight level height (from leaf) with agwidth number of nodes 3683 * each, which starts at agstart index node of the smmary tree node 3684 * array; 3685 */ 3686 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize); 3687 l2nl = 3688 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL); 3689 bmp->db_agheight = l2nl >> 1; 3690 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1)); 3691 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0; 3692 i--) { 3693 bmp->db_agstart += n; 3694 n <<= 2; 3695 } 3696 3697 } 3698 3699 3700 /* 3701 * NAME: dbInitDmap()/ujfs_idmap_page() 3702 * 3703 * FUNCTION: initialize working/persistent bitmap of the dmap page 3704 * for the specified number of blocks: 3705 * 3706 * at entry, the bitmaps had been initialized as free (ZEROS); 3707 * The number of blocks will only account for the actually 3708 * existing blocks. Blocks which don't actually exist in 3709 * the aggregate will be marked as allocated (ONES); 3710 * 3711 * PARAMETERS: 3712 * dp - pointer to page of map 3713 * nblocks - number of blocks this page 3714 * 3715 * RETURNS: NONE 3716 */ 3717 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks) 3718 { 3719 int blkno, w, b, r, nw, nb, i; 3720 3721 /* starting block number within the dmap */ 3722 blkno = Blkno & (BPERDMAP - 1); 3723 3724 if (blkno == 0) { 3725 dp->nblocks = dp->nfree = cpu_to_le32(nblocks); 3726 dp->start = cpu_to_le64(Blkno); 3727 3728 if (nblocks == BPERDMAP) { 3729 memset(&dp->wmap[0], 0, LPERDMAP * 4); 3730 memset(&dp->pmap[0], 0, LPERDMAP * 4); 3731 goto initTree; 3732 } 3733 } else { 3734 le32_add_cpu(&dp->nblocks, nblocks); 3735 le32_add_cpu(&dp->nfree, nblocks); 3736 } 3737 3738 /* word number containing start block number */ 3739 w = blkno >> L2DBWORD; 3740 3741 /* 3742 * free the bits corresponding to the block range (ZEROS): 3743 * note: not all bits of the first and last words may be contained 3744 * within the block range. 3745 */ 3746 for (r = nblocks; r > 0; r -= nb, blkno += nb) { 3747 /* number of bits preceding range to be freed in the word */ 3748 b = blkno & (DBWORD - 1); 3749 /* number of bits to free in the word */ 3750 nb = min(r, DBWORD - b); 3751 3752 /* is partial word to be freed ? */ 3753 if (nb < DBWORD) { 3754 /* free (set to 0) from the bitmap word */ 3755 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3756 >> b)); 3757 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3758 >> b)); 3759 3760 /* skip the word freed */ 3761 w++; 3762 } else { 3763 /* free (set to 0) contiguous bitmap words */ 3764 nw = r >> L2DBWORD; 3765 memset(&dp->wmap[w], 0, nw * 4); 3766 memset(&dp->pmap[w], 0, nw * 4); 3767 3768 /* skip the words freed */ 3769 nb = nw << L2DBWORD; 3770 w += nw; 3771 } 3772 } 3773 3774 /* 3775 * mark bits following the range to be freed (non-existing 3776 * blocks) as allocated (ONES) 3777 */ 3778 3779 if (blkno == BPERDMAP) 3780 goto initTree; 3781 3782 /* the first word beyond the end of existing blocks */ 3783 w = blkno >> L2DBWORD; 3784 3785 /* does nblocks fall on a 32-bit boundary ? */ 3786 b = blkno & (DBWORD - 1); 3787 if (b) { 3788 /* mark a partial word allocated */ 3789 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b); 3790 w++; 3791 } 3792 3793 /* set the rest of the words in the page to allocated (ONES) */ 3794 for (i = w; i < LPERDMAP; i++) 3795 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES); 3796 3797 /* 3798 * init tree 3799 */ 3800 initTree: 3801 return (dbInitDmapTree(dp)); 3802 } 3803 3804 3805 /* 3806 * NAME: dbInitDmapTree()/ujfs_complete_dmap() 3807 * 3808 * FUNCTION: initialize summary tree of the specified dmap: 3809 * 3810 * at entry, bitmap of the dmap has been initialized; 3811 * 3812 * PARAMETERS: 3813 * dp - dmap to complete 3814 * blkno - starting block number for this dmap 3815 * treemax - will be filled in with max free for this dmap 3816 * 3817 * RETURNS: max free string at the root of the tree 3818 */ 3819 static int dbInitDmapTree(struct dmap * dp) 3820 { 3821 struct dmaptree *tp; 3822 s8 *cp; 3823 int i; 3824 3825 /* init fixed info of tree */ 3826 tp = &dp->tree; 3827 tp->nleafs = cpu_to_le32(LPERDMAP); 3828 tp->l2nleafs = cpu_to_le32(L2LPERDMAP); 3829 tp->leafidx = cpu_to_le32(LEAFIND); 3830 tp->height = cpu_to_le32(4); 3831 tp->budmin = BUDMIN; 3832 3833 /* init each leaf from corresponding wmap word: 3834 * note: leaf is set to NOFREE(-1) if all blocks of corresponding 3835 * bitmap word are allocated. 3836 */ 3837 cp = tp->stree + le32_to_cpu(tp->leafidx); 3838 for (i = 0; i < LPERDMAP; i++) 3839 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]); 3840 3841 /* build the dmap's binary buddy summary tree */ 3842 return (dbInitTree(tp)); 3843 } 3844 3845 3846 /* 3847 * NAME: dbInitTree()/ujfs_adjtree() 3848 * 3849 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl. 3850 * 3851 * at entry, the leaves of the tree has been initialized 3852 * from corresponding bitmap word or root of summary tree 3853 * of the child control page; 3854 * configure binary buddy system at the leaf level, then 3855 * bubble up the values of the leaf nodes up the tree. 3856 * 3857 * PARAMETERS: 3858 * cp - Pointer to the root of the tree 3859 * l2leaves- Number of leaf nodes as a power of 2 3860 * l2min - Number of blocks that can be covered by a leaf 3861 * as a power of 2 3862 * 3863 * RETURNS: max free string at the root of the tree 3864 */ 3865 static int dbInitTree(struct dmaptree * dtp) 3866 { 3867 int l2max, l2free, bsize, nextb, i; 3868 int child, parent, nparent; 3869 s8 *tp, *cp, *cp1; 3870 3871 tp = dtp->stree; 3872 3873 /* Determine the maximum free string possible for the leaves */ 3874 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin; 3875 3876 /* 3877 * configure the leaf level into binary buddy system 3878 * 3879 * Try to combine buddies starting with a buddy size of 1 3880 * (i.e. two leaves). At a buddy size of 1 two buddy leaves 3881 * can be combined if both buddies have a maximum free of l2min; 3882 * the combination will result in the left-most buddy leaf having 3883 * a maximum free of l2min+1. 3884 * After processing all buddies for a given size, process buddies 3885 * at the next higher buddy size (i.e. current size * 2) and 3886 * the next maximum free (current free + 1). 3887 * This continues until the maximum possible buddy combination 3888 * yields maximum free. 3889 */ 3890 for (l2free = dtp->budmin, bsize = 1; l2free < l2max; 3891 l2free++, bsize = nextb) { 3892 /* get next buddy size == current buddy pair size */ 3893 nextb = bsize << 1; 3894 3895 /* scan each adjacent buddy pair at current buddy size */ 3896 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx); 3897 i < le32_to_cpu(dtp->nleafs); 3898 i += nextb, cp += nextb) { 3899 /* coalesce if both adjacent buddies are max free */ 3900 if (*cp == l2free && *(cp + bsize) == l2free) { 3901 *cp = l2free + 1; /* left take right */ 3902 *(cp + bsize) = -1; /* right give left */ 3903 } 3904 } 3905 } 3906 3907 /* 3908 * bubble summary information of leaves up the tree. 3909 * 3910 * Starting at the leaf node level, the four nodes described by 3911 * the higher level parent node are compared for a maximum free and 3912 * this maximum becomes the value of the parent node. 3913 * when all lower level nodes are processed in this fashion then 3914 * move up to the next level (parent becomes a lower level node) and 3915 * continue the process for that level. 3916 */ 3917 for (child = le32_to_cpu(dtp->leafidx), 3918 nparent = le32_to_cpu(dtp->nleafs) >> 2; 3919 nparent > 0; nparent >>= 2, child = parent) { 3920 /* get index of 1st node of parent level */ 3921 parent = (child - 1) >> 2; 3922 3923 /* set the value of the parent node as the maximum 3924 * of the four nodes of the current level. 3925 */ 3926 for (i = 0, cp = tp + child, cp1 = tp + parent; 3927 i < nparent; i++, cp += 4, cp1++) 3928 *cp1 = TREEMAX(cp); 3929 } 3930 3931 return (*tp); 3932 } 3933 3934 3935 /* 3936 * dbInitDmapCtl() 3937 * 3938 * function: initialize dmapctl page 3939 */ 3940 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i) 3941 { /* start leaf index not covered by range */ 3942 s8 *cp; 3943 3944 dcp->nleafs = cpu_to_le32(LPERCTL); 3945 dcp->l2nleafs = cpu_to_le32(L2LPERCTL); 3946 dcp->leafidx = cpu_to_le32(CTLLEAFIND); 3947 dcp->height = cpu_to_le32(5); 3948 dcp->budmin = L2BPERDMAP + L2LPERCTL * level; 3949 3950 /* 3951 * initialize the leaves of current level that were not covered 3952 * by the specified input block range (i.e. the leaves have no 3953 * low level dmapctl or dmap). 3954 */ 3955 cp = &dcp->stree[CTLLEAFIND + i]; 3956 for (; i < LPERCTL; i++) 3957 *cp++ = NOFREE; 3958 3959 /* build the dmap's binary buddy summary tree */ 3960 return (dbInitTree((struct dmaptree *) dcp)); 3961 } 3962 3963 3964 /* 3965 * NAME: dbGetL2AGSize()/ujfs_getagl2size() 3966 * 3967 * FUNCTION: Determine log2(allocation group size) from aggregate size 3968 * 3969 * PARAMETERS: 3970 * nblocks - Number of blocks in aggregate 3971 * 3972 * RETURNS: log2(allocation group size) in aggregate blocks 3973 */ 3974 static int dbGetL2AGSize(s64 nblocks) 3975 { 3976 s64 sz; 3977 s64 m; 3978 int l2sz; 3979 3980 if (nblocks < BPERDMAP * MAXAG) 3981 return (L2BPERDMAP); 3982 3983 /* round up aggregate size to power of 2 */ 3984 m = ((u64) 1 << (64 - 1)); 3985 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) { 3986 if (m & nblocks) 3987 break; 3988 } 3989 3990 sz = (s64) 1 << l2sz; 3991 if (sz < nblocks) 3992 l2sz += 1; 3993 3994 /* agsize = roundupSize/max_number_of_ag */ 3995 return (l2sz - L2MAXAG); 3996 } 3997 3998 3999 /* 4000 * NAME: dbMapFileSizeToMapSize() 4001 * 4002 * FUNCTION: compute number of blocks the block allocation map file 4003 * can cover from the map file size; 4004 * 4005 * RETURNS: Number of blocks which can be covered by this block map file; 4006 */ 4007 4008 /* 4009 * maximum number of map pages at each level including control pages 4010 */ 4011 #define MAXL0PAGES (1 + LPERCTL) 4012 #define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES) 4013 4014 /* 4015 * convert number of map pages to the zero origin top dmapctl level 4016 */ 4017 #define BMAPPGTOLEV(npages) \ 4018 (((npages) <= 3 + MAXL0PAGES) ? 0 : \ 4019 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2) 4020 4021 s64 dbMapFileSizeToMapSize(struct inode * ipbmap) 4022 { 4023 struct super_block *sb = ipbmap->i_sb; 4024 s64 nblocks; 4025 s64 npages, ndmaps; 4026 int level, i; 4027 int complete, factor; 4028 4029 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize; 4030 npages = nblocks >> JFS_SBI(sb)->l2nbperpage; 4031 level = BMAPPGTOLEV(npages); 4032 4033 /* At each level, accumulate the number of dmap pages covered by 4034 * the number of full child levels below it; 4035 * repeat for the last incomplete child level. 4036 */ 4037 ndmaps = 0; 4038 npages--; /* skip the first global control page */ 4039 /* skip higher level control pages above top level covered by map */ 4040 npages -= (2 - level); 4041 npages--; /* skip top level's control page */ 4042 for (i = level; i >= 0; i--) { 4043 factor = 4044 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1); 4045 complete = (u32) npages / factor; 4046 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL : 4047 ((i == 1) ? LPERCTL : 1)); 4048 4049 /* pages in last/incomplete child */ 4050 npages = (u32) npages % factor; 4051 /* skip incomplete child's level control page */ 4052 npages--; 4053 } 4054 4055 /* convert the number of dmaps into the number of blocks 4056 * which can be covered by the dmaps; 4057 */ 4058 nblocks = ndmaps << L2BPERDMAP; 4059 4060 return (nblocks); 4061 } 4062