1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) International Business Machines Corp., 2000-2004 4 * Portions Copyright (C) Tino Reichardt, 2012 5 */ 6 7 #include <linux/fs.h> 8 #include <linux/slab.h> 9 #include "jfs_incore.h" 10 #include "jfs_superblock.h" 11 #include "jfs_dmap.h" 12 #include "jfs_imap.h" 13 #include "jfs_lock.h" 14 #include "jfs_metapage.h" 15 #include "jfs_debug.h" 16 #include "jfs_discard.h" 17 18 /* 19 * SERIALIZATION of the Block Allocation Map. 20 * 21 * the working state of the block allocation map is accessed in 22 * two directions: 23 * 24 * 1) allocation and free requests that start at the dmap 25 * level and move up through the dmap control pages (i.e. 26 * the vast majority of requests). 27 * 28 * 2) allocation requests that start at dmap control page 29 * level and work down towards the dmaps. 30 * 31 * the serialization scheme used here is as follows. 32 * 33 * requests which start at the bottom are serialized against each 34 * other through buffers and each requests holds onto its buffers 35 * as it works it way up from a single dmap to the required level 36 * of dmap control page. 37 * requests that start at the top are serialized against each other 38 * and request that start from the bottom by the multiple read/single 39 * write inode lock of the bmap inode. requests starting at the top 40 * take this lock in write mode while request starting at the bottom 41 * take the lock in read mode. a single top-down request may proceed 42 * exclusively while multiple bottoms-up requests may proceed 43 * simultaneously (under the protection of busy buffers). 44 * 45 * in addition to information found in dmaps and dmap control pages, 46 * the working state of the block allocation map also includes read/ 47 * write information maintained in the bmap descriptor (i.e. total 48 * free block count, allocation group level free block counts). 49 * a single exclusive lock (BMAP_LOCK) is used to guard this information 50 * in the face of multiple-bottoms up requests. 51 * (lock ordering: IREAD_LOCK, BMAP_LOCK); 52 * 53 * accesses to the persistent state of the block allocation map (limited 54 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers. 55 */ 56 57 #define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock) 58 #define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock) 59 #define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock) 60 61 /* 62 * forward references 63 */ 64 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 65 int nblocks); 66 static void dbSplit(dmtree_t *tp, int leafno, int splitsz, int newval, bool is_ctl); 67 static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl); 68 static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl); 69 static void dbAdjTree(dmtree_t *tp, int leafno, int newval, bool is_ctl); 70 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, 71 int level); 72 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results); 73 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno, 74 int nblocks); 75 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno, 76 int nblocks, 77 int l2nb, s64 * results); 78 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 79 int nblocks); 80 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks, 81 int l2nb, 82 s64 * results); 83 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, 84 s64 * results); 85 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, 86 s64 * results); 87 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks); 88 static int dbFindBits(u32 word, int l2nb); 89 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno); 90 static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl); 91 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 92 int nblocks); 93 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 94 int nblocks); 95 static int dbMaxBud(u8 * cp); 96 static int blkstol2(s64 nb); 97 98 static int cntlz(u32 value); 99 static int cnttz(u32 word); 100 101 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 102 int nblocks); 103 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks); 104 static int dbInitDmapTree(struct dmap * dp); 105 static int dbInitTree(struct dmaptree * dtp); 106 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i); 107 static int dbGetL2AGSize(s64 nblocks); 108 109 /* 110 * buddy table 111 * 112 * table used for determining buddy sizes within characters of 113 * dmap bitmap words. the characters themselves serve as indexes 114 * into the table, with the table elements yielding the maximum 115 * binary buddy of free bits within the character. 116 */ 117 static const s8 budtab[256] = { 118 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 119 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 120 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 121 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 122 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 123 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 124 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 125 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 126 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 127 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 128 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 129 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 130 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 131 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 132 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 133 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1 134 }; 135 136 /* 137 * NAME: dbMount() 138 * 139 * FUNCTION: initializate the block allocation map. 140 * 141 * memory is allocated for the in-core bmap descriptor and 142 * the in-core descriptor is initialized from disk. 143 * 144 * PARAMETERS: 145 * ipbmap - pointer to in-core inode for the block map. 146 * 147 * RETURN VALUES: 148 * 0 - success 149 * -ENOMEM - insufficient memory 150 * -EIO - i/o error 151 * -EINVAL - wrong bmap data 152 */ 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 || bmp->db_numag >= MAXAG) { 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 if (unlikely(l2nb < 0)) 1630 break; 1631 nblocks = 1LL << l2nb; 1632 } else { 1633 /* Trim any already allocated blocks */ 1634 jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n"); 1635 break; 1636 } 1637 1638 /* check, if our trim array is full */ 1639 if (unlikely(count >= range_cnt - 1)) 1640 break; 1641 } 1642 IWRITE_UNLOCK(ipbmap); 1643 1644 tt->nblocks = 0; /* mark the current end */ 1645 for (tt = totrim; tt->nblocks != 0; tt++) { 1646 /* when mounted with online discard, dbFree() will 1647 * call jfs_issue_discard() itself */ 1648 if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) 1649 jfs_issue_discard(ip, tt->blkno, tt->nblocks); 1650 dbFree(ip, tt->blkno, tt->nblocks); 1651 trimmed += tt->nblocks; 1652 } 1653 kfree(totrim); 1654 1655 return trimmed; 1656 } 1657 1658 /* 1659 * NAME: dbFindCtl() 1660 * 1661 * FUNCTION: starting at a specified dmap control page level and block 1662 * number, search down the dmap control levels for a range of 1663 * contiguous free blocks large enough to satisfy an allocation 1664 * request for the specified number of free blocks. 1665 * 1666 * if sufficient contiguous free blocks are found, this routine 1667 * returns the starting block number within a dmap page that 1668 * contains or starts a range of contiqious free blocks that 1669 * is sufficient in size. 1670 * 1671 * PARAMETERS: 1672 * bmp - pointer to bmap descriptor 1673 * level - starting dmap control page level. 1674 * l2nb - log2 number of contiguous free blocks desired. 1675 * *blkno - on entry, starting block number for conducting the search. 1676 * on successful return, the first block within a dmap page 1677 * that contains or starts a range of contiguous free blocks. 1678 * 1679 * RETURN VALUES: 1680 * 0 - success 1681 * -ENOSPC - insufficient disk resources 1682 * -EIO - i/o error 1683 * 1684 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1685 */ 1686 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno) 1687 { 1688 int rc, leafidx, lev; 1689 s64 b, lblkno; 1690 struct dmapctl *dcp; 1691 int budmin; 1692 struct metapage *mp; 1693 1694 /* starting at the specified dmap control page level and block 1695 * number, search down the dmap control levels for the starting 1696 * block number of a dmap page that contains or starts off 1697 * sufficient free blocks. 1698 */ 1699 for (lev = level, b = *blkno; lev >= 0; lev--) { 1700 /* get the buffer of the dmap control page for the block 1701 * number and level (i.e. L0, L1, L2). 1702 */ 1703 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev); 1704 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1705 if (mp == NULL) 1706 return -EIO; 1707 dcp = (struct dmapctl *) mp->data; 1708 budmin = dcp->budmin; 1709 1710 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 1711 jfs_error(bmp->db_ipbmap->i_sb, 1712 "Corrupt dmapctl page\n"); 1713 release_metapage(mp); 1714 return -EIO; 1715 } 1716 1717 /* search the tree within the dmap control page for 1718 * sufficient free space. if sufficient free space is found, 1719 * dbFindLeaf() returns the index of the leaf at which 1720 * free space was found. 1721 */ 1722 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx, true); 1723 1724 /* release the buffer. 1725 */ 1726 release_metapage(mp); 1727 1728 /* space found ? 1729 */ 1730 if (rc) { 1731 if (lev != level) { 1732 jfs_error(bmp->db_ipbmap->i_sb, 1733 "dmap inconsistent\n"); 1734 return -EIO; 1735 } 1736 return -ENOSPC; 1737 } 1738 1739 /* adjust the block number to reflect the location within 1740 * the dmap control page (i.e. the leaf) at which free 1741 * space was found. 1742 */ 1743 b += (((s64) leafidx) << budmin); 1744 1745 /* we stop the search at this dmap control page level if 1746 * the number of blocks required is greater than or equal 1747 * to the maximum number of blocks described at the next 1748 * (lower) level. 1749 */ 1750 if (l2nb >= budmin) 1751 break; 1752 } 1753 1754 *blkno = b; 1755 return (0); 1756 } 1757 1758 1759 /* 1760 * NAME: dbAllocCtl() 1761 * 1762 * FUNCTION: attempt to allocate a specified number of contiguous 1763 * blocks starting within a specific dmap. 1764 * 1765 * this routine is called by higher level routines that search 1766 * the dmap control pages above the actual dmaps for contiguous 1767 * free space. the result of successful searches by these 1768 * routines are the starting block numbers within dmaps, with 1769 * the dmaps themselves containing the desired contiguous free 1770 * space or starting a contiguous free space of desired size 1771 * that is made up of the blocks of one or more dmaps. these 1772 * calls should not fail due to insufficent resources. 1773 * 1774 * this routine is called in some cases where it is not known 1775 * whether it will fail due to insufficient resources. more 1776 * specifically, this occurs when allocating from an allocation 1777 * group whose size is equal to the number of blocks per dmap. 1778 * in this case, the dmap control pages are not examined prior 1779 * to calling this routine (to save pathlength) and the call 1780 * might fail. 1781 * 1782 * for a request size that fits within a dmap, this routine relies 1783 * upon the dmap's dmtree to find the requested contiguous free 1784 * space. for request sizes that are larger than a dmap, the 1785 * requested free space will start at the first block of the 1786 * first dmap (i.e. blkno). 1787 * 1788 * PARAMETERS: 1789 * bmp - pointer to bmap descriptor 1790 * nblocks - actual number of contiguous free blocks to allocate. 1791 * l2nb - log2 number of contiguous free blocks to allocate. 1792 * blkno - starting block number of the dmap to start the allocation 1793 * from. 1794 * results - on successful return, set to the starting block number 1795 * of the newly allocated range. 1796 * 1797 * RETURN VALUES: 1798 * 0 - success 1799 * -ENOSPC - insufficient disk resources 1800 * -EIO - i/o error 1801 * 1802 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit; 1803 */ 1804 static int 1805 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results) 1806 { 1807 int rc, nb; 1808 s64 b, lblkno, n; 1809 struct metapage *mp; 1810 struct dmap *dp; 1811 1812 /* check if the allocation request is confined to a single dmap. 1813 */ 1814 if (l2nb <= L2BPERDMAP) { 1815 /* get the buffer for the dmap. 1816 */ 1817 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 1818 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1819 if (mp == NULL) 1820 return -EIO; 1821 dp = (struct dmap *) mp->data; 1822 1823 /* try to allocate the blocks. 1824 */ 1825 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results); 1826 if (rc == 0) 1827 mark_metapage_dirty(mp); 1828 1829 release_metapage(mp); 1830 1831 return (rc); 1832 } 1833 1834 /* allocation request involving multiple dmaps. it must start on 1835 * a dmap boundary. 1836 */ 1837 assert((blkno & (BPERDMAP - 1)) == 0); 1838 1839 /* allocate the blocks dmap by dmap. 1840 */ 1841 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) { 1842 /* get the buffer for the dmap. 1843 */ 1844 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1845 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1846 if (mp == NULL) { 1847 rc = -EIO; 1848 goto backout; 1849 } 1850 dp = (struct dmap *) mp->data; 1851 1852 /* the dmap better be all free. 1853 */ 1854 if (dp->tree.stree[ROOT] != L2BPERDMAP) { 1855 release_metapage(mp); 1856 jfs_error(bmp->db_ipbmap->i_sb, 1857 "the dmap is not all free\n"); 1858 rc = -EIO; 1859 goto backout; 1860 } 1861 1862 /* determine how many blocks to allocate from this dmap. 1863 */ 1864 nb = min_t(s64, n, BPERDMAP); 1865 1866 /* allocate the blocks from the dmap. 1867 */ 1868 if ((rc = dbAllocDmap(bmp, dp, b, nb))) { 1869 release_metapage(mp); 1870 goto backout; 1871 } 1872 1873 /* write the buffer. 1874 */ 1875 write_metapage(mp); 1876 } 1877 1878 /* set the results (starting block number) and return. 1879 */ 1880 *results = blkno; 1881 return (0); 1882 1883 /* something failed in handling an allocation request involving 1884 * multiple dmaps. we'll try to clean up by backing out any 1885 * allocation that has already happened for this request. if 1886 * we fail in backing out the allocation, we'll mark the file 1887 * system to indicate that blocks have been leaked. 1888 */ 1889 backout: 1890 1891 /* try to backout the allocations dmap by dmap. 1892 */ 1893 for (n = nblocks - n, b = blkno; n > 0; 1894 n -= BPERDMAP, b += BPERDMAP) { 1895 /* get the buffer for this dmap. 1896 */ 1897 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage); 1898 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 1899 if (mp == NULL) { 1900 /* could not back out. mark the file system 1901 * to indicate that we have leaked blocks. 1902 */ 1903 jfs_error(bmp->db_ipbmap->i_sb, 1904 "I/O Error: Block Leakage\n"); 1905 continue; 1906 } 1907 dp = (struct dmap *) mp->data; 1908 1909 /* free the blocks is this dmap. 1910 */ 1911 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) { 1912 /* could not back out. mark the file system 1913 * to indicate that we have leaked blocks. 1914 */ 1915 release_metapage(mp); 1916 jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n"); 1917 continue; 1918 } 1919 1920 /* write the buffer. 1921 */ 1922 write_metapage(mp); 1923 } 1924 1925 return (rc); 1926 } 1927 1928 1929 /* 1930 * NAME: dbAllocDmapLev() 1931 * 1932 * FUNCTION: attempt to allocate a specified number of contiguous blocks 1933 * from a specified dmap. 1934 * 1935 * this routine checks if the contiguous blocks are available. 1936 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is 1937 * returned. 1938 * 1939 * PARAMETERS: 1940 * mp - pointer to bmap descriptor 1941 * dp - pointer to dmap to attempt to allocate blocks from. 1942 * l2nb - log2 number of contiguous block desired. 1943 * nblocks - actual number of contiguous block desired. 1944 * results - on successful return, set to the starting block number 1945 * of the newly allocated range. 1946 * 1947 * RETURN VALUES: 1948 * 0 - success 1949 * -ENOSPC - insufficient disk resources 1950 * -EIO - i/o error 1951 * 1952 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or 1953 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit; 1954 */ 1955 static int 1956 dbAllocDmapLev(struct bmap * bmp, 1957 struct dmap * dp, int nblocks, int l2nb, s64 * results) 1958 { 1959 s64 blkno; 1960 int leafidx, rc; 1961 1962 /* can't be more than a dmaps worth of blocks */ 1963 assert(l2nb <= L2BPERDMAP); 1964 1965 /* search the tree within the dmap page for sufficient 1966 * free space. if sufficient free space is found, dbFindLeaf() 1967 * returns the index of the leaf at which free space was found. 1968 */ 1969 if (dbFindLeaf((dmtree_t *) &dp->tree, l2nb, &leafidx, false)) 1970 return -ENOSPC; 1971 1972 if (leafidx < 0) 1973 return -EIO; 1974 1975 /* determine the block number within the file system corresponding 1976 * to the leaf at which free space was found. 1977 */ 1978 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD); 1979 1980 /* if not all bits of the dmap word are free, get the starting 1981 * bit number within the dmap word of the required string of free 1982 * bits and adjust the block number with this value. 1983 */ 1984 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN) 1985 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb); 1986 1987 /* allocate the blocks */ 1988 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0) 1989 *results = blkno; 1990 1991 return (rc); 1992 } 1993 1994 1995 /* 1996 * NAME: dbAllocDmap() 1997 * 1998 * FUNCTION: adjust the disk allocation map to reflect the allocation 1999 * of a specified block range within a dmap. 2000 * 2001 * this routine allocates the specified blocks from the dmap 2002 * through a call to dbAllocBits(). if the allocation of the 2003 * block range causes the maximum string of free blocks within 2004 * the dmap to change (i.e. the value of the root of the dmap's 2005 * dmtree), this routine will cause this change to be reflected 2006 * up through the appropriate levels of the dmap control pages 2007 * by a call to dbAdjCtl() for the L0 dmap control page that 2008 * covers this dmap. 2009 * 2010 * PARAMETERS: 2011 * bmp - pointer to bmap descriptor 2012 * dp - pointer to dmap to allocate the block range from. 2013 * blkno - starting block number of the block to be allocated. 2014 * nblocks - number of blocks to be allocated. 2015 * 2016 * RETURN VALUES: 2017 * 0 - success 2018 * -EIO - i/o error 2019 * 2020 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2021 */ 2022 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2023 int nblocks) 2024 { 2025 s8 oldroot; 2026 int rc; 2027 2028 /* save the current value of the root (i.e. maximum free string) 2029 * of the dmap tree. 2030 */ 2031 oldroot = dp->tree.stree[ROOT]; 2032 2033 /* allocate the specified (blocks) bits */ 2034 dbAllocBits(bmp, dp, blkno, nblocks); 2035 2036 /* if the root has not changed, done. */ 2037 if (dp->tree.stree[ROOT] == oldroot) 2038 return (0); 2039 2040 /* root changed. bubble the change up to the dmap control pages. 2041 * if the adjustment of the upper level control pages fails, 2042 * backout the bit allocation (thus making everything consistent). 2043 */ 2044 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0))) 2045 dbFreeBits(bmp, dp, blkno, nblocks); 2046 2047 return (rc); 2048 } 2049 2050 2051 /* 2052 * NAME: dbFreeDmap() 2053 * 2054 * FUNCTION: adjust the disk allocation map to reflect the allocation 2055 * of a specified block range within a dmap. 2056 * 2057 * this routine frees the specified blocks from the dmap through 2058 * a call to dbFreeBits(). if the deallocation of the block range 2059 * causes the maximum string of free blocks within the dmap to 2060 * change (i.e. the value of the root of the dmap's dmtree), this 2061 * routine will cause this change to be reflected up through the 2062 * appropriate levels of the dmap control pages by a call to 2063 * dbAdjCtl() for the L0 dmap control page that covers this dmap. 2064 * 2065 * PARAMETERS: 2066 * bmp - pointer to bmap descriptor 2067 * dp - pointer to dmap to free the block range from. 2068 * blkno - starting block number of the block to be freed. 2069 * nblocks - number of blocks to be freed. 2070 * 2071 * RETURN VALUES: 2072 * 0 - success 2073 * -EIO - i/o error 2074 * 2075 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2076 */ 2077 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno, 2078 int nblocks) 2079 { 2080 s8 oldroot; 2081 int rc = 0, word; 2082 2083 /* save the current value of the root (i.e. maximum free string) 2084 * of the dmap tree. 2085 */ 2086 oldroot = dp->tree.stree[ROOT]; 2087 2088 /* free the specified (blocks) bits */ 2089 rc = dbFreeBits(bmp, dp, blkno, nblocks); 2090 2091 /* if error or the root has not changed, done. */ 2092 if (rc || (dp->tree.stree[ROOT] == oldroot)) 2093 return (rc); 2094 2095 /* root changed. bubble the change up to the dmap control pages. 2096 * if the adjustment of the upper level control pages fails, 2097 * backout the deallocation. 2098 */ 2099 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) { 2100 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD; 2101 2102 /* as part of backing out the deallocation, we will have 2103 * to back split the dmap tree if the deallocation caused 2104 * the freed blocks to become part of a larger binary buddy 2105 * system. 2106 */ 2107 if (dp->tree.stree[word] == NOFREE) 2108 dbBackSplit((dmtree_t *)&dp->tree, word, false); 2109 2110 dbAllocBits(bmp, dp, blkno, nblocks); 2111 } 2112 2113 return (rc); 2114 } 2115 2116 2117 /* 2118 * NAME: dbAllocBits() 2119 * 2120 * FUNCTION: allocate a specified block range from a dmap. 2121 * 2122 * this routine updates the dmap to reflect the working 2123 * state allocation of the specified block range. it directly 2124 * updates the bits of the working map and causes the adjustment 2125 * of the binary buddy system described by the dmap's dmtree 2126 * leaves to reflect the bits allocated. it also causes the 2127 * dmap's dmtree, as a whole, to reflect the allocated range. 2128 * 2129 * PARAMETERS: 2130 * bmp - pointer to bmap descriptor 2131 * dp - pointer to dmap to allocate bits from. 2132 * blkno - starting block number of the bits to be allocated. 2133 * nblocks - number of bits to be allocated. 2134 * 2135 * RETURN VALUES: none 2136 * 2137 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2138 */ 2139 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2140 int nblocks) 2141 { 2142 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2143 dmtree_t *tp = (dmtree_t *) & dp->tree; 2144 int size; 2145 s8 *leaf; 2146 2147 /* pick up a pointer to the leaves of the dmap tree */ 2148 leaf = dp->tree.stree + LEAFIND; 2149 2150 /* determine the bit number and word within the dmap of the 2151 * starting block. 2152 */ 2153 dbitno = blkno & (BPERDMAP - 1); 2154 word = dbitno >> L2DBWORD; 2155 2156 /* block range better be within the dmap */ 2157 assert(dbitno + nblocks <= BPERDMAP); 2158 2159 /* allocate the bits of the dmap's words corresponding to the block 2160 * range. not all bits of the first and last words may be contained 2161 * within the block range. if this is the case, we'll work against 2162 * those words (i.e. partial first and/or last) on an individual basis 2163 * (a single pass), allocating the bits of interest by hand and 2164 * updating the leaf corresponding to the dmap word. a single pass 2165 * will be used for all dmap words fully contained within the 2166 * specified range. within this pass, the bits of all fully contained 2167 * dmap words will be marked as free in a single shot and the leaves 2168 * will be updated. a single leaf may describe the free space of 2169 * multiple dmap words, so we may update only a subset of the actual 2170 * leaves corresponding to the dmap words of the block range. 2171 */ 2172 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2173 /* determine the bit number within the word and 2174 * the number of bits within the word. 2175 */ 2176 wbitno = dbitno & (DBWORD - 1); 2177 nb = min(rembits, DBWORD - wbitno); 2178 2179 /* check if only part of a word is to be allocated. 2180 */ 2181 if (nb < DBWORD) { 2182 /* allocate (set to 1) the appropriate bits within 2183 * this dmap word. 2184 */ 2185 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 2186 >> wbitno); 2187 2188 /* update the leaf for this dmap word. in addition 2189 * to setting the leaf value to the binary buddy max 2190 * of the updated dmap word, dbSplit() will split 2191 * the binary system of the leaves if need be. 2192 */ 2193 dbSplit(tp, word, BUDMIN, 2194 dbMaxBud((u8 *)&dp->wmap[word]), false); 2195 2196 word += 1; 2197 } else { 2198 /* one or more dmap words are fully contained 2199 * within the block range. determine how many 2200 * words and allocate (set to 1) the bits of these 2201 * words. 2202 */ 2203 nwords = rembits >> L2DBWORD; 2204 memset(&dp->wmap[word], (int) ONES, nwords * 4); 2205 2206 /* determine how many bits. 2207 */ 2208 nb = nwords << L2DBWORD; 2209 2210 /* now update the appropriate leaves to reflect 2211 * the allocated words. 2212 */ 2213 for (; nwords > 0; nwords -= nw) { 2214 if (leaf[word] < BUDMIN) { 2215 jfs_error(bmp->db_ipbmap->i_sb, 2216 "leaf page corrupt\n"); 2217 break; 2218 } 2219 2220 /* determine what the leaf value should be 2221 * updated to as the minimum of the l2 number 2222 * of bits being allocated and the l2 number 2223 * of bits currently described by this leaf. 2224 */ 2225 size = min_t(int, leaf[word], 2226 NLSTOL2BSZ(nwords)); 2227 2228 /* update the leaf to reflect the allocation. 2229 * in addition to setting the leaf value to 2230 * NOFREE, dbSplit() will split the binary 2231 * system of the leaves to reflect the current 2232 * allocation (size). 2233 */ 2234 dbSplit(tp, word, size, NOFREE, false); 2235 2236 /* get the number of dmap words handled */ 2237 nw = BUDSIZE(size, BUDMIN); 2238 word += nw; 2239 } 2240 } 2241 } 2242 2243 /* update the free count for this dmap */ 2244 le32_add_cpu(&dp->nfree, -nblocks); 2245 2246 BMAP_LOCK(bmp); 2247 2248 /* if this allocation group is completely free, 2249 * update the maximum allocation group number if this allocation 2250 * group is the new max. 2251 */ 2252 agno = blkno >> bmp->db_agl2size; 2253 if (agno > bmp->db_maxag) 2254 bmp->db_maxag = agno; 2255 2256 /* update the free count for the allocation group and map */ 2257 bmp->db_agfree[agno] -= nblocks; 2258 bmp->db_nfree -= nblocks; 2259 2260 BMAP_UNLOCK(bmp); 2261 } 2262 2263 2264 /* 2265 * NAME: dbFreeBits() 2266 * 2267 * FUNCTION: free a specified block range from a dmap. 2268 * 2269 * this routine updates the dmap to reflect the working 2270 * state allocation of the specified block range. it directly 2271 * updates the bits of the working map and causes the adjustment 2272 * of the binary buddy system described by the dmap's dmtree 2273 * leaves to reflect the bits freed. it also causes the dmap's 2274 * dmtree, as a whole, to reflect the deallocated range. 2275 * 2276 * PARAMETERS: 2277 * bmp - pointer to bmap descriptor 2278 * dp - pointer to dmap to free bits from. 2279 * blkno - starting block number of the bits to be freed. 2280 * nblocks - number of bits to be freed. 2281 * 2282 * RETURN VALUES: 0 for success 2283 * 2284 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2285 */ 2286 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno, 2287 int nblocks) 2288 { 2289 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno; 2290 dmtree_t *tp = (dmtree_t *) & dp->tree; 2291 int rc = 0; 2292 int size; 2293 2294 /* determine the bit number and word within the dmap of the 2295 * starting block. 2296 */ 2297 dbitno = blkno & (BPERDMAP - 1); 2298 word = dbitno >> L2DBWORD; 2299 2300 /* block range better be within the dmap. 2301 */ 2302 assert(dbitno + nblocks <= BPERDMAP); 2303 2304 /* free the bits of the dmaps words corresponding to the block range. 2305 * not all bits of the first and last words may be contained within 2306 * the block range. if this is the case, we'll work against those 2307 * words (i.e. partial first and/or last) on an individual basis 2308 * (a single pass), freeing the bits of interest by hand and updating 2309 * the leaf corresponding to the dmap word. a single pass will be used 2310 * for all dmap words fully contained within the specified range. 2311 * within this pass, the bits of all fully contained dmap words will 2312 * be marked as free in a single shot and the leaves will be updated. a 2313 * single leaf may describe the free space of multiple dmap words, 2314 * so we may update only a subset of the actual leaves corresponding 2315 * to the dmap words of the block range. 2316 * 2317 * dbJoin() is used to update leaf values and will join the binary 2318 * buddy system of the leaves if the new leaf values indicate this 2319 * should be done. 2320 */ 2321 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 2322 /* determine the bit number within the word and 2323 * the number of bits within the word. 2324 */ 2325 wbitno = dbitno & (DBWORD - 1); 2326 nb = min(rembits, DBWORD - wbitno); 2327 2328 /* check if only part of a word is to be freed. 2329 */ 2330 if (nb < DBWORD) { 2331 /* free (zero) the appropriate bits within this 2332 * dmap word. 2333 */ 2334 dp->wmap[word] &= 2335 cpu_to_le32(~(ONES << (DBWORD - nb) 2336 >> wbitno)); 2337 2338 /* update the leaf for this dmap word. 2339 */ 2340 rc = dbJoin(tp, word, 2341 dbMaxBud((u8 *)&dp->wmap[word]), false); 2342 if (rc) 2343 return rc; 2344 2345 word += 1; 2346 } else { 2347 /* one or more dmap words are fully contained 2348 * within the block range. determine how many 2349 * words and free (zero) the bits of these words. 2350 */ 2351 nwords = rembits >> L2DBWORD; 2352 memset(&dp->wmap[word], 0, nwords * 4); 2353 2354 /* determine how many bits. 2355 */ 2356 nb = nwords << L2DBWORD; 2357 2358 /* now update the appropriate leaves to reflect 2359 * the freed words. 2360 */ 2361 for (; nwords > 0; nwords -= nw) { 2362 /* determine what the leaf value should be 2363 * updated to as the minimum of the l2 number 2364 * of bits being freed and the l2 (max) number 2365 * of bits that can be described by this leaf. 2366 */ 2367 size = 2368 min(LITOL2BSZ 2369 (word, L2LPERDMAP, BUDMIN), 2370 NLSTOL2BSZ(nwords)); 2371 2372 /* update the leaf. 2373 */ 2374 rc = dbJoin(tp, word, size, false); 2375 if (rc) 2376 return rc; 2377 2378 /* get the number of dmap words handled. 2379 */ 2380 nw = BUDSIZE(size, BUDMIN); 2381 word += nw; 2382 } 2383 } 2384 } 2385 2386 /* update the free count for this dmap. 2387 */ 2388 le32_add_cpu(&dp->nfree, nblocks); 2389 2390 BMAP_LOCK(bmp); 2391 2392 /* update the free count for the allocation group and 2393 * map. 2394 */ 2395 agno = blkno >> bmp->db_agl2size; 2396 bmp->db_nfree += nblocks; 2397 bmp->db_agfree[agno] += nblocks; 2398 2399 /* check if this allocation group is not completely free and 2400 * if it is currently the maximum (rightmost) allocation group. 2401 * if so, establish the new maximum allocation group number by 2402 * searching left for the first allocation group with allocation. 2403 */ 2404 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) || 2405 (agno == bmp->db_numag - 1 && 2406 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) { 2407 while (bmp->db_maxag > 0) { 2408 bmp->db_maxag -= 1; 2409 if (bmp->db_agfree[bmp->db_maxag] != 2410 bmp->db_agsize) 2411 break; 2412 } 2413 2414 /* re-establish the allocation group preference if the 2415 * current preference is right of the maximum allocation 2416 * group. 2417 */ 2418 if (bmp->db_agpref > bmp->db_maxag) 2419 bmp->db_agpref = bmp->db_maxag; 2420 } 2421 2422 BMAP_UNLOCK(bmp); 2423 2424 return 0; 2425 } 2426 2427 2428 /* 2429 * NAME: dbAdjCtl() 2430 * 2431 * FUNCTION: adjust a dmap control page at a specified level to reflect 2432 * the change in a lower level dmap or dmap control page's 2433 * maximum string of free blocks (i.e. a change in the root 2434 * of the lower level object's dmtree) due to the allocation 2435 * or deallocation of a range of blocks with a single dmap. 2436 * 2437 * on entry, this routine is provided with the new value of 2438 * the lower level dmap or dmap control page root and the 2439 * starting block number of the block range whose allocation 2440 * or deallocation resulted in the root change. this range 2441 * is respresented by a single leaf of the current dmapctl 2442 * and the leaf will be updated with this value, possibly 2443 * causing a binary buddy system within the leaves to be 2444 * split or joined. the update may also cause the dmapctl's 2445 * dmtree to be updated. 2446 * 2447 * if the adjustment of the dmap control page, itself, causes its 2448 * root to change, this change will be bubbled up to the next dmap 2449 * control level by a recursive call to this routine, specifying 2450 * the new root value and the next dmap control page level to 2451 * be adjusted. 2452 * PARAMETERS: 2453 * bmp - pointer to bmap descriptor 2454 * blkno - the first block of a block range within a dmap. it is 2455 * the allocation or deallocation of this block range that 2456 * requires the dmap control page to be adjusted. 2457 * newval - the new value of the lower level dmap or dmap control 2458 * page root. 2459 * alloc - 'true' if adjustment is due to an allocation. 2460 * level - current level of dmap control page (i.e. L0, L1, L2) to 2461 * be adjusted. 2462 * 2463 * RETURN VALUES: 2464 * 0 - success 2465 * -EIO - i/o error 2466 * 2467 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2468 */ 2469 static int 2470 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level) 2471 { 2472 struct metapage *mp; 2473 s8 oldroot; 2474 int oldval; 2475 s64 lblkno; 2476 struct dmapctl *dcp; 2477 int rc, leafno, ti; 2478 2479 /* get the buffer for the dmap control page for the specified 2480 * block number and control page level. 2481 */ 2482 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level); 2483 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0); 2484 if (mp == NULL) 2485 return -EIO; 2486 dcp = (struct dmapctl *) mp->data; 2487 2488 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { 2489 jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); 2490 release_metapage(mp); 2491 return -EIO; 2492 } 2493 2494 /* determine the leaf number corresponding to the block and 2495 * the index within the dmap control tree. 2496 */ 2497 leafno = BLKTOCTLLEAF(blkno, dcp->budmin); 2498 ti = leafno + le32_to_cpu(dcp->leafidx); 2499 2500 /* save the current leaf value and the current root level (i.e. 2501 * maximum l2 free string described by this dmapctl). 2502 */ 2503 oldval = dcp->stree[ti]; 2504 oldroot = dcp->stree[ROOT]; 2505 2506 /* check if this is a control page update for an allocation. 2507 * if so, update the leaf to reflect the new leaf value using 2508 * dbSplit(); otherwise (deallocation), use dbJoin() to update 2509 * the leaf with the new value. in addition to updating the 2510 * leaf, dbSplit() will also split the binary buddy system of 2511 * the leaves, if required, and bubble new values within the 2512 * dmapctl tree, if required. similarly, dbJoin() will join 2513 * the binary buddy system of leaves and bubble new values up 2514 * the dmapctl tree as required by the new leaf value. 2515 */ 2516 if (alloc) { 2517 /* check if we are in the middle of a binary buddy 2518 * system. this happens when we are performing the 2519 * first allocation out of an allocation group that 2520 * is part (not the first part) of a larger binary 2521 * buddy system. if we are in the middle, back split 2522 * the system prior to calling dbSplit() which assumes 2523 * that it is at the front of a binary buddy system. 2524 */ 2525 if (oldval == NOFREE) { 2526 rc = dbBackSplit((dmtree_t *)dcp, leafno, true); 2527 if (rc) { 2528 release_metapage(mp); 2529 return rc; 2530 } 2531 oldval = dcp->stree[ti]; 2532 } 2533 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval, true); 2534 } else { 2535 rc = dbJoin((dmtree_t *) dcp, leafno, newval, true); 2536 if (rc) { 2537 release_metapage(mp); 2538 return rc; 2539 } 2540 } 2541 2542 /* check if the root of the current dmap control page changed due 2543 * to the update and if the current dmap control page is not at 2544 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e. 2545 * root changed and this is not the top level), call this routine 2546 * again (recursion) for the next higher level of the mapping to 2547 * reflect the change in root for the current dmap control page. 2548 */ 2549 if (dcp->stree[ROOT] != oldroot) { 2550 /* are we below the top level of the map. if so, 2551 * bubble the root up to the next higher level. 2552 */ 2553 if (level < bmp->db_maxlevel) { 2554 /* bubble up the new root of this dmap control page to 2555 * the next level. 2556 */ 2557 if ((rc = 2558 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc, 2559 level + 1))) { 2560 /* something went wrong in bubbling up the new 2561 * root value, so backout the changes to the 2562 * current dmap control page. 2563 */ 2564 if (alloc) { 2565 dbJoin((dmtree_t *) dcp, leafno, 2566 oldval, true); 2567 } else { 2568 /* the dbJoin() above might have 2569 * caused a larger binary buddy system 2570 * to form and we may now be in the 2571 * middle of it. if this is the case, 2572 * back split the buddies. 2573 */ 2574 if (dcp->stree[ti] == NOFREE) 2575 dbBackSplit((dmtree_t *) 2576 dcp, leafno, true); 2577 dbSplit((dmtree_t *) dcp, leafno, 2578 dcp->budmin, oldval, true); 2579 } 2580 2581 /* release the buffer and return the error. 2582 */ 2583 release_metapage(mp); 2584 return (rc); 2585 } 2586 } else { 2587 /* we're at the top level of the map. update 2588 * the bmap control page to reflect the size 2589 * of the maximum free buddy system. 2590 */ 2591 assert(level == bmp->db_maxlevel); 2592 if (bmp->db_maxfreebud != oldroot) { 2593 jfs_error(bmp->db_ipbmap->i_sb, 2594 "the maximum free buddy is not the old root\n"); 2595 } 2596 bmp->db_maxfreebud = dcp->stree[ROOT]; 2597 } 2598 } 2599 2600 /* write the buffer. 2601 */ 2602 write_metapage(mp); 2603 2604 return (0); 2605 } 2606 2607 2608 /* 2609 * NAME: dbSplit() 2610 * 2611 * FUNCTION: update the leaf of a dmtree with a new value, splitting 2612 * the leaf from the binary buddy system of the dmtree's 2613 * leaves, as required. 2614 * 2615 * PARAMETERS: 2616 * tp - pointer to the tree containing the leaf. 2617 * leafno - the number of the leaf to be updated. 2618 * splitsz - the size the binary buddy system starting at the leaf 2619 * must be split to, specified as the log2 number of blocks. 2620 * newval - the new value for the leaf. 2621 * 2622 * RETURN VALUES: none 2623 * 2624 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2625 */ 2626 static void dbSplit(dmtree_t *tp, int leafno, int splitsz, int newval, bool is_ctl) 2627 { 2628 int budsz; 2629 int cursz; 2630 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2631 2632 /* check if the leaf needs to be split. 2633 */ 2634 if (leaf[leafno] > tp->dmt_budmin) { 2635 /* the split occurs by cutting the buddy system in half 2636 * at the specified leaf until we reach the specified 2637 * size. pick up the starting split size (current size 2638 * - 1 in l2) and the corresponding buddy size. 2639 */ 2640 cursz = leaf[leafno] - 1; 2641 budsz = BUDSIZE(cursz, tp->dmt_budmin); 2642 2643 /* split until we reach the specified size. 2644 */ 2645 while (cursz >= splitsz) { 2646 /* update the buddy's leaf with its new value. 2647 */ 2648 dbAdjTree(tp, leafno ^ budsz, cursz, is_ctl); 2649 2650 /* on to the next size and buddy. 2651 */ 2652 cursz -= 1; 2653 budsz >>= 1; 2654 } 2655 } 2656 2657 /* adjust the dmap tree to reflect the specified leaf's new 2658 * value. 2659 */ 2660 dbAdjTree(tp, leafno, newval, is_ctl); 2661 } 2662 2663 2664 /* 2665 * NAME: dbBackSplit() 2666 * 2667 * FUNCTION: back split the binary buddy system of dmtree leaves 2668 * that hold a specified leaf until the specified leaf 2669 * starts its own binary buddy system. 2670 * 2671 * the allocators typically perform allocations at the start 2672 * of binary buddy systems and dbSplit() is used to accomplish 2673 * any required splits. in some cases, however, allocation 2674 * may occur in the middle of a binary system and requires a 2675 * back split, with the split proceeding out from the middle of 2676 * the system (less efficient) rather than the start of the 2677 * system (more efficient). the cases in which a back split 2678 * is required are rare and are limited to the first allocation 2679 * within an allocation group which is a part (not first part) 2680 * of a larger binary buddy system and a few exception cases 2681 * in which a previous join operation must be backed out. 2682 * 2683 * PARAMETERS: 2684 * tp - pointer to the tree containing the leaf. 2685 * leafno - the number of the leaf to be updated. 2686 * 2687 * RETURN VALUES: none 2688 * 2689 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; 2690 */ 2691 static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl) 2692 { 2693 int budsz, bud, w, bsz, size; 2694 int cursz; 2695 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2696 2697 /* leaf should be part (not first part) of a binary 2698 * buddy system. 2699 */ 2700 assert(leaf[leafno] == NOFREE); 2701 2702 /* the back split is accomplished by iteratively finding the leaf 2703 * that starts the buddy system that contains the specified leaf and 2704 * splitting that system in two. this iteration continues until 2705 * the specified leaf becomes the start of a buddy system. 2706 * 2707 * determine maximum possible l2 size for the specified leaf. 2708 */ 2709 size = 2710 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs), 2711 tp->dmt_budmin); 2712 2713 /* determine the number of leaves covered by this size. this 2714 * is the buddy size that we will start with as we search for 2715 * the buddy system that contains the specified leaf. 2716 */ 2717 budsz = BUDSIZE(size, tp->dmt_budmin); 2718 2719 /* back split. 2720 */ 2721 while (leaf[leafno] == NOFREE) { 2722 /* find the leftmost buddy leaf. 2723 */ 2724 for (w = leafno, bsz = budsz;; bsz <<= 1, 2725 w = (w < bud) ? w : bud) { 2726 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) { 2727 jfs_err("JFS: block map error in dbBackSplit"); 2728 return -EIO; 2729 } 2730 2731 /* determine the buddy. 2732 */ 2733 bud = w ^ bsz; 2734 2735 /* check if this buddy is the start of the system. 2736 */ 2737 if (leaf[bud] != NOFREE) { 2738 /* split the leaf at the start of the 2739 * system in two. 2740 */ 2741 cursz = leaf[bud] - 1; 2742 dbSplit(tp, bud, cursz, cursz, is_ctl); 2743 break; 2744 } 2745 } 2746 } 2747 2748 if (leaf[leafno] != size) { 2749 jfs_err("JFS: wrong leaf value in dbBackSplit"); 2750 return -EIO; 2751 } 2752 return 0; 2753 } 2754 2755 2756 /* 2757 * NAME: dbJoin() 2758 * 2759 * FUNCTION: update the leaf of a dmtree with a new value, joining 2760 * the leaf with other leaves of the dmtree into a multi-leaf 2761 * binary buddy system, as required. 2762 * 2763 * PARAMETERS: 2764 * tp - pointer to the tree containing the leaf. 2765 * leafno - the number of the leaf to be updated. 2766 * newval - the new value for the leaf. 2767 * 2768 * RETURN VALUES: none 2769 */ 2770 static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl) 2771 { 2772 int budsz, buddy; 2773 s8 *leaf; 2774 2775 /* can the new leaf value require a join with other leaves ? 2776 */ 2777 if (newval >= tp->dmt_budmin) { 2778 /* pickup a pointer to the leaves of the tree. 2779 */ 2780 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx); 2781 2782 /* try to join the specified leaf into a large binary 2783 * buddy system. the join proceeds by attempting to join 2784 * the specified leafno with its buddy (leaf) at new value. 2785 * if the join occurs, we attempt to join the left leaf 2786 * of the joined buddies with its buddy at new value + 1. 2787 * we continue to join until we find a buddy that cannot be 2788 * joined (does not have a value equal to the size of the 2789 * last join) or until all leaves have been joined into a 2790 * single system. 2791 * 2792 * get the buddy size (number of words covered) of 2793 * the new value. 2794 */ 2795 budsz = BUDSIZE(newval, tp->dmt_budmin); 2796 2797 /* try to join. 2798 */ 2799 while (budsz < le32_to_cpu(tp->dmt_nleafs)) { 2800 /* get the buddy leaf. 2801 */ 2802 buddy = leafno ^ budsz; 2803 2804 /* if the leaf's new value is greater than its 2805 * buddy's value, we join no more. 2806 */ 2807 if (newval > leaf[buddy]) 2808 break; 2809 2810 /* It shouldn't be less */ 2811 if (newval < leaf[buddy]) 2812 return -EIO; 2813 2814 /* check which (leafno or buddy) is the left buddy. 2815 * the left buddy gets to claim the blocks resulting 2816 * from the join while the right gets to claim none. 2817 * the left buddy is also eligible to participate in 2818 * a join at the next higher level while the right 2819 * is not. 2820 * 2821 */ 2822 if (leafno < buddy) { 2823 /* leafno is the left buddy. 2824 */ 2825 dbAdjTree(tp, buddy, NOFREE, is_ctl); 2826 } else { 2827 /* buddy is the left buddy and becomes 2828 * leafno. 2829 */ 2830 dbAdjTree(tp, leafno, NOFREE, is_ctl); 2831 leafno = buddy; 2832 } 2833 2834 /* on to try the next join. 2835 */ 2836 newval += 1; 2837 budsz <<= 1; 2838 } 2839 } 2840 2841 /* update the leaf value. 2842 */ 2843 dbAdjTree(tp, leafno, newval, is_ctl); 2844 2845 return 0; 2846 } 2847 2848 2849 /* 2850 * NAME: dbAdjTree() 2851 * 2852 * FUNCTION: update a leaf of a dmtree with a new value, adjusting 2853 * the dmtree, as required, to reflect the new leaf value. 2854 * the combination of any buddies must already be done before 2855 * this is called. 2856 * 2857 * PARAMETERS: 2858 * tp - pointer to the tree to be adjusted. 2859 * leafno - the number of the leaf to be updated. 2860 * newval - the new value for the leaf. 2861 * 2862 * RETURN VALUES: none 2863 */ 2864 static void dbAdjTree(dmtree_t *tp, int leafno, int newval, bool is_ctl) 2865 { 2866 int lp, pp, k; 2867 int max, size; 2868 2869 size = is_ctl ? CTLTREESIZE : TREESIZE; 2870 2871 /* pick up the index of the leaf for this leafno. 2872 */ 2873 lp = leafno + le32_to_cpu(tp->dmt_leafidx); 2874 2875 if (WARN_ON_ONCE(lp >= size || lp < 0)) 2876 return; 2877 2878 /* is the current value the same as the old value ? if so, 2879 * there is nothing to do. 2880 */ 2881 if (tp->dmt_stree[lp] == newval) 2882 return; 2883 2884 /* set the new value. 2885 */ 2886 tp->dmt_stree[lp] = newval; 2887 2888 /* bubble the new value up the tree as required. 2889 */ 2890 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) { 2891 /* get the index of the first leaf of the 4 leaf 2892 * group containing the specified leaf (leafno). 2893 */ 2894 lp = ((lp - 1) & ~0x03) + 1; 2895 2896 /* get the index of the parent of this 4 leaf group. 2897 */ 2898 pp = (lp - 1) >> 2; 2899 2900 /* determine the maximum of the 4 leaves. 2901 */ 2902 max = TREEMAX(&tp->dmt_stree[lp]); 2903 2904 /* if the maximum of the 4 is the same as the 2905 * parent's value, we're done. 2906 */ 2907 if (tp->dmt_stree[pp] == max) 2908 break; 2909 2910 /* parent gets new value. 2911 */ 2912 tp->dmt_stree[pp] = max; 2913 2914 /* parent becomes leaf for next go-round. 2915 */ 2916 lp = pp; 2917 } 2918 } 2919 2920 2921 /* 2922 * NAME: dbFindLeaf() 2923 * 2924 * FUNCTION: search a dmtree_t for sufficient free blocks, returning 2925 * the index of a leaf describing the free blocks if 2926 * sufficient free blocks are found. 2927 * 2928 * the search starts at the top of the dmtree_t tree and 2929 * proceeds down the tree to the leftmost leaf with sufficient 2930 * free space. 2931 * 2932 * PARAMETERS: 2933 * tp - pointer to the tree to be searched. 2934 * l2nb - log2 number of free blocks to search for. 2935 * leafidx - return pointer to be set to the index of the leaf 2936 * describing at least l2nb free blocks if sufficient 2937 * free blocks are found. 2938 * is_ctl - determines if the tree is of type ctl 2939 * 2940 * RETURN VALUES: 2941 * 0 - success 2942 * -ENOSPC - insufficient free blocks. 2943 */ 2944 static int dbFindLeaf(dmtree_t *tp, int l2nb, int *leafidx, bool is_ctl) 2945 { 2946 int ti, n = 0, k, x = 0; 2947 int max_size; 2948 2949 max_size = is_ctl ? CTLTREESIZE : TREESIZE; 2950 2951 /* first check the root of the tree to see if there is 2952 * sufficient free space. 2953 */ 2954 if (l2nb > tp->dmt_stree[ROOT]) 2955 return -ENOSPC; 2956 2957 /* sufficient free space available. now search down the tree 2958 * starting at the next level for the leftmost leaf that 2959 * describes sufficient free space. 2960 */ 2961 for (k = le32_to_cpu(tp->dmt_height), ti = 1; 2962 k > 0; k--, ti = ((ti + n) << 2) + 1) { 2963 /* search the four nodes at this level, starting from 2964 * the left. 2965 */ 2966 for (x = ti, n = 0; n < 4; n++) { 2967 /* sufficient free space found. move to the next 2968 * level (or quit if this is the last level). 2969 */ 2970 if (x + n > max_size) 2971 return -ENOSPC; 2972 if (l2nb <= tp->dmt_stree[x + n]) 2973 break; 2974 } 2975 2976 /* better have found something since the higher 2977 * levels of the tree said it was here. 2978 */ 2979 assert(n < 4); 2980 } 2981 2982 /* set the return to the leftmost leaf describing sufficient 2983 * free space. 2984 */ 2985 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx); 2986 2987 return (0); 2988 } 2989 2990 2991 /* 2992 * NAME: dbFindBits() 2993 * 2994 * FUNCTION: find a specified number of binary buddy free bits within a 2995 * dmap bitmap word value. 2996 * 2997 * this routine searches the bitmap value for (1 << l2nb) free 2998 * bits at (1 << l2nb) alignments within the value. 2999 * 3000 * PARAMETERS: 3001 * word - dmap bitmap word value. 3002 * l2nb - number of free bits specified as a log2 number. 3003 * 3004 * RETURN VALUES: 3005 * starting bit number of free bits. 3006 */ 3007 static int dbFindBits(u32 word, int l2nb) 3008 { 3009 int bitno, nb; 3010 u32 mask; 3011 3012 /* get the number of bits. 3013 */ 3014 nb = 1 << l2nb; 3015 assert(nb <= DBWORD); 3016 3017 /* complement the word so we can use a mask (i.e. 0s represent 3018 * free bits) and compute the mask. 3019 */ 3020 word = ~word; 3021 mask = ONES << (DBWORD - nb); 3022 3023 /* scan the word for nb free bits at nb alignments. 3024 */ 3025 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) { 3026 if ((mask & word) == mask) 3027 break; 3028 } 3029 3030 ASSERT(bitno < 32); 3031 3032 /* return the bit number. 3033 */ 3034 return (bitno); 3035 } 3036 3037 3038 /* 3039 * NAME: dbMaxBud(u8 *cp) 3040 * 3041 * FUNCTION: determine the largest binary buddy string of free 3042 * bits within 32-bits of the map. 3043 * 3044 * PARAMETERS: 3045 * cp - pointer to the 32-bit value. 3046 * 3047 * RETURN VALUES: 3048 * largest binary buddy of free bits within a dmap word. 3049 */ 3050 static int dbMaxBud(u8 * cp) 3051 { 3052 signed char tmp1, tmp2; 3053 3054 /* check if the wmap word is all free. if so, the 3055 * free buddy size is BUDMIN. 3056 */ 3057 if (*((uint *) cp) == 0) 3058 return (BUDMIN); 3059 3060 /* check if the wmap word is half free. if so, the 3061 * free buddy size is BUDMIN-1. 3062 */ 3063 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0) 3064 return (BUDMIN - 1); 3065 3066 /* not all free or half free. determine the free buddy 3067 * size thru table lookup using quarters of the wmap word. 3068 */ 3069 tmp1 = max(budtab[cp[2]], budtab[cp[3]]); 3070 tmp2 = max(budtab[cp[0]], budtab[cp[1]]); 3071 return (max(tmp1, tmp2)); 3072 } 3073 3074 3075 /* 3076 * NAME: cnttz(uint word) 3077 * 3078 * FUNCTION: determine the number of trailing zeros within a 32-bit 3079 * value. 3080 * 3081 * PARAMETERS: 3082 * value - 32-bit value to be examined. 3083 * 3084 * RETURN VALUES: 3085 * count of trailing zeros 3086 */ 3087 static int cnttz(u32 word) 3088 { 3089 int n; 3090 3091 for (n = 0; n < 32; n++, word >>= 1) { 3092 if (word & 0x01) 3093 break; 3094 } 3095 3096 return (n); 3097 } 3098 3099 3100 /* 3101 * NAME: cntlz(u32 value) 3102 * 3103 * FUNCTION: determine the number of leading zeros within a 32-bit 3104 * value. 3105 * 3106 * PARAMETERS: 3107 * value - 32-bit value to be examined. 3108 * 3109 * RETURN VALUES: 3110 * count of leading zeros 3111 */ 3112 static int cntlz(u32 value) 3113 { 3114 int n; 3115 3116 for (n = 0; n < 32; n++, value <<= 1) { 3117 if (value & HIGHORDER) 3118 break; 3119 } 3120 return (n); 3121 } 3122 3123 3124 /* 3125 * NAME: blkstol2(s64 nb) 3126 * 3127 * FUNCTION: convert a block count to its log2 value. if the block 3128 * count is not a l2 multiple, it is rounded up to the next 3129 * larger l2 multiple. 3130 * 3131 * PARAMETERS: 3132 * nb - number of blocks 3133 * 3134 * RETURN VALUES: 3135 * log2 number of blocks 3136 */ 3137 static int blkstol2(s64 nb) 3138 { 3139 int l2nb; 3140 s64 mask; /* meant to be signed */ 3141 3142 mask = (s64) 1 << (64 - 1); 3143 3144 /* count the leading bits. 3145 */ 3146 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) { 3147 /* leading bit found. 3148 */ 3149 if (nb & mask) { 3150 /* determine the l2 value. 3151 */ 3152 l2nb = (64 - 1) - l2nb; 3153 3154 /* check if we need to round up. 3155 */ 3156 if (~mask & nb) 3157 l2nb++; 3158 3159 return (l2nb); 3160 } 3161 } 3162 assert(0); 3163 return 0; /* fix compiler warning */ 3164 } 3165 3166 3167 /* 3168 * NAME: dbAllocBottomUp() 3169 * 3170 * FUNCTION: alloc the specified block range from the working block 3171 * allocation map. 3172 * 3173 * the blocks will be alloc from the working map one dmap 3174 * at a time. 3175 * 3176 * PARAMETERS: 3177 * ip - pointer to in-core inode; 3178 * blkno - starting block number to be freed. 3179 * nblocks - number of blocks to be freed. 3180 * 3181 * RETURN VALUES: 3182 * 0 - success 3183 * -EIO - i/o error 3184 */ 3185 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks) 3186 { 3187 struct metapage *mp; 3188 struct dmap *dp; 3189 int nb, rc; 3190 s64 lblkno, rem; 3191 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; 3192 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; 3193 3194 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); 3195 3196 /* block to be allocated better be within the mapsize. */ 3197 ASSERT(nblocks <= bmp->db_mapsize - blkno); 3198 3199 /* 3200 * allocate the blocks a dmap at a time. 3201 */ 3202 mp = NULL; 3203 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) { 3204 /* release previous dmap if any */ 3205 if (mp) { 3206 write_metapage(mp); 3207 } 3208 3209 /* get the buffer for the current dmap. */ 3210 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage); 3211 mp = read_metapage(ipbmap, lblkno, PSIZE, 0); 3212 if (mp == NULL) { 3213 IREAD_UNLOCK(ipbmap); 3214 return -EIO; 3215 } 3216 dp = (struct dmap *) mp->data; 3217 3218 /* determine the number of blocks to be allocated from 3219 * this dmap. 3220 */ 3221 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1))); 3222 3223 /* allocate the blocks. */ 3224 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) { 3225 release_metapage(mp); 3226 IREAD_UNLOCK(ipbmap); 3227 return (rc); 3228 } 3229 } 3230 3231 /* write the last buffer. */ 3232 write_metapage(mp); 3233 3234 IREAD_UNLOCK(ipbmap); 3235 3236 return (0); 3237 } 3238 3239 3240 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno, 3241 int nblocks) 3242 { 3243 int rc; 3244 int dbitno, word, rembits, nb, nwords, wbitno, agno; 3245 s8 oldroot; 3246 struct dmaptree *tp = (struct dmaptree *) & dp->tree; 3247 3248 /* save the current value of the root (i.e. maximum free string) 3249 * of the dmap tree. 3250 */ 3251 oldroot = tp->stree[ROOT]; 3252 3253 /* determine the bit number and word within the dmap of the 3254 * starting block. 3255 */ 3256 dbitno = blkno & (BPERDMAP - 1); 3257 word = dbitno >> L2DBWORD; 3258 3259 /* block range better be within the dmap */ 3260 assert(dbitno + nblocks <= BPERDMAP); 3261 3262 /* allocate the bits of the dmap's words corresponding to the block 3263 * range. not all bits of the first and last words may be contained 3264 * within the block range. if this is the case, we'll work against 3265 * those words (i.e. partial first and/or last) on an individual basis 3266 * (a single pass), allocating the bits of interest by hand and 3267 * updating the leaf corresponding to the dmap word. a single pass 3268 * will be used for all dmap words fully contained within the 3269 * specified range. within this pass, the bits of all fully contained 3270 * dmap words will be marked as free in a single shot and the leaves 3271 * will be updated. a single leaf may describe the free space of 3272 * multiple dmap words, so we may update only a subset of the actual 3273 * leaves corresponding to the dmap words of the block range. 3274 */ 3275 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) { 3276 /* determine the bit number within the word and 3277 * the number of bits within the word. 3278 */ 3279 wbitno = dbitno & (DBWORD - 1); 3280 nb = min(rembits, DBWORD - wbitno); 3281 3282 /* check if only part of a word is to be allocated. 3283 */ 3284 if (nb < DBWORD) { 3285 /* allocate (set to 1) the appropriate bits within 3286 * this dmap word. 3287 */ 3288 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb) 3289 >> wbitno); 3290 3291 word++; 3292 } else { 3293 /* one or more dmap words are fully contained 3294 * within the block range. determine how many 3295 * words and allocate (set to 1) the bits of these 3296 * words. 3297 */ 3298 nwords = rembits >> L2DBWORD; 3299 memset(&dp->wmap[word], (int) ONES, nwords * 4); 3300 3301 /* determine how many bits */ 3302 nb = nwords << L2DBWORD; 3303 word += nwords; 3304 } 3305 } 3306 3307 /* update the free count for this dmap */ 3308 le32_add_cpu(&dp->nfree, -nblocks); 3309 3310 /* reconstruct summary tree */ 3311 dbInitDmapTree(dp); 3312 3313 BMAP_LOCK(bmp); 3314 3315 /* if this allocation group is completely free, 3316 * update the highest active allocation group number 3317 * if this allocation group is the new max. 3318 */ 3319 agno = blkno >> bmp->db_agl2size; 3320 if (agno > bmp->db_maxag) 3321 bmp->db_maxag = agno; 3322 3323 /* update the free count for the allocation group and map */ 3324 bmp->db_agfree[agno] -= nblocks; 3325 bmp->db_nfree -= nblocks; 3326 3327 BMAP_UNLOCK(bmp); 3328 3329 /* if the root has not changed, done. */ 3330 if (tp->stree[ROOT] == oldroot) 3331 return (0); 3332 3333 /* root changed. bubble the change up to the dmap control pages. 3334 * if the adjustment of the upper level control pages fails, 3335 * backout the bit allocation (thus making everything consistent). 3336 */ 3337 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0))) 3338 dbFreeBits(bmp, dp, blkno, nblocks); 3339 3340 return (rc); 3341 } 3342 3343 3344 /* 3345 * NAME: dbExtendFS() 3346 * 3347 * FUNCTION: extend bmap from blkno for nblocks; 3348 * dbExtendFS() updates bmap ready for dbAllocBottomUp(); 3349 * 3350 * L2 3351 * | 3352 * L1---------------------------------L1 3353 * | | 3354 * L0---------L0---------L0 L0---------L0---------L0 3355 * | | | | | | 3356 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm; 3357 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm 3358 * 3359 * <---old---><----------------------------extend-----------------------> 3360 */ 3361 int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks) 3362 { 3363 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb); 3364 int nbperpage = sbi->nbperpage; 3365 int i, i0 = true, j, j0 = true, k, n; 3366 s64 newsize; 3367 s64 p; 3368 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL; 3369 struct dmapctl *l2dcp, *l1dcp, *l0dcp; 3370 struct dmap *dp; 3371 s8 *l0leaf, *l1leaf, *l2leaf; 3372 struct bmap *bmp = sbi->bmap; 3373 int agno, l2agsize, oldl2agsize; 3374 s64 ag_rem; 3375 3376 newsize = blkno + nblocks; 3377 3378 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld", 3379 (long long) blkno, (long long) nblocks, (long long) newsize); 3380 3381 /* 3382 * initialize bmap control page. 3383 * 3384 * all the data in bmap control page should exclude 3385 * the mkfs hidden dmap page. 3386 */ 3387 3388 /* update mapsize */ 3389 bmp->db_mapsize = newsize; 3390 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize); 3391 3392 /* compute new AG size */ 3393 l2agsize = dbGetL2AGSize(newsize); 3394 oldl2agsize = bmp->db_agl2size; 3395 3396 bmp->db_agl2size = l2agsize; 3397 bmp->db_agsize = 1 << l2agsize; 3398 3399 /* compute new number of AG */ 3400 agno = bmp->db_numag; 3401 bmp->db_numag = newsize >> l2agsize; 3402 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0; 3403 3404 /* 3405 * reconfigure db_agfree[] 3406 * from old AG configuration to new AG configuration; 3407 * 3408 * coalesce contiguous k (newAGSize/oldAGSize) AGs; 3409 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn; 3410 * note: new AG size = old AG size * (2**x). 3411 */ 3412 if (l2agsize == oldl2agsize) 3413 goto extend; 3414 k = 1 << (l2agsize - oldl2agsize); 3415 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */ 3416 for (i = 0, n = 0; i < agno; n++) { 3417 bmp->db_agfree[n] = 0; /* init collection point */ 3418 3419 /* coalesce contiguous k AGs; */ 3420 for (j = 0; j < k && i < agno; j++, i++) { 3421 /* merge AGi to AGn */ 3422 bmp->db_agfree[n] += bmp->db_agfree[i]; 3423 } 3424 } 3425 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */ 3426 3427 for (; n < MAXAG; n++) 3428 bmp->db_agfree[n] = 0; 3429 3430 /* 3431 * update highest active ag number 3432 */ 3433 3434 bmp->db_maxag = bmp->db_maxag / k; 3435 3436 /* 3437 * extend bmap 3438 * 3439 * update bit maps and corresponding level control pages; 3440 * global control page db_nfree, db_agfree[agno], db_maxfreebud; 3441 */ 3442 extend: 3443 /* get L2 page */ 3444 p = BMAPBLKNO + nbperpage; /* L2 page */ 3445 l2mp = read_metapage(ipbmap, p, PSIZE, 0); 3446 if (!l2mp) { 3447 jfs_error(ipbmap->i_sb, "L2 page could not be read\n"); 3448 return -EIO; 3449 } 3450 l2dcp = (struct dmapctl *) l2mp->data; 3451 3452 /* compute start L1 */ 3453 k = blkno >> L2MAXL1SIZE; 3454 l2leaf = l2dcp->stree + CTLLEAFIND + k; 3455 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */ 3456 3457 /* 3458 * extend each L1 in L2 3459 */ 3460 for (; k < LPERCTL; k++, p += nbperpage) { 3461 /* get L1 page */ 3462 if (j0) { 3463 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */ 3464 l1mp = read_metapage(ipbmap, p, PSIZE, 0); 3465 if (l1mp == NULL) 3466 goto errout; 3467 l1dcp = (struct dmapctl *) l1mp->data; 3468 3469 /* compute start L0 */ 3470 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE; 3471 l1leaf = l1dcp->stree + CTLLEAFIND + j; 3472 p = BLKTOL0(blkno, sbi->l2nbperpage); 3473 j0 = false; 3474 } else { 3475 /* assign/init L1 page */ 3476 l1mp = get_metapage(ipbmap, p, PSIZE, 0); 3477 if (l1mp == NULL) 3478 goto errout; 3479 3480 l1dcp = (struct dmapctl *) l1mp->data; 3481 3482 /* compute start L0 */ 3483 j = 0; 3484 l1leaf = l1dcp->stree + CTLLEAFIND; 3485 p += nbperpage; /* 1st L0 of L1.k */ 3486 } 3487 3488 /* 3489 * extend each L0 in L1 3490 */ 3491 for (; j < LPERCTL; j++) { 3492 /* get L0 page */ 3493 if (i0) { 3494 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */ 3495 3496 l0mp = read_metapage(ipbmap, p, PSIZE, 0); 3497 if (l0mp == NULL) 3498 goto errout; 3499 l0dcp = (struct dmapctl *) l0mp->data; 3500 3501 /* compute start dmap */ 3502 i = (blkno & (MAXL0SIZE - 1)) >> 3503 L2BPERDMAP; 3504 l0leaf = l0dcp->stree + CTLLEAFIND + i; 3505 p = BLKTODMAP(blkno, 3506 sbi->l2nbperpage); 3507 i0 = false; 3508 } else { 3509 /* assign/init L0 page */ 3510 l0mp = get_metapage(ipbmap, p, PSIZE, 0); 3511 if (l0mp == NULL) 3512 goto errout; 3513 3514 l0dcp = (struct dmapctl *) l0mp->data; 3515 3516 /* compute start dmap */ 3517 i = 0; 3518 l0leaf = l0dcp->stree + CTLLEAFIND; 3519 p += nbperpage; /* 1st dmap of L0.j */ 3520 } 3521 3522 /* 3523 * extend each dmap in L0 3524 */ 3525 for (; i < LPERCTL; i++) { 3526 /* 3527 * reconstruct the dmap page, and 3528 * initialize corresponding parent L0 leaf 3529 */ 3530 if ((n = blkno & (BPERDMAP - 1))) { 3531 /* read in dmap page: */ 3532 mp = read_metapage(ipbmap, p, 3533 PSIZE, 0); 3534 if (mp == NULL) 3535 goto errout; 3536 n = min(nblocks, (s64)BPERDMAP - n); 3537 } else { 3538 /* assign/init dmap page */ 3539 mp = read_metapage(ipbmap, p, 3540 PSIZE, 0); 3541 if (mp == NULL) 3542 goto errout; 3543 3544 n = min_t(s64, nblocks, BPERDMAP); 3545 } 3546 3547 dp = (struct dmap *) mp->data; 3548 *l0leaf = dbInitDmap(dp, blkno, n); 3549 3550 bmp->db_nfree += n; 3551 agno = le64_to_cpu(dp->start) >> l2agsize; 3552 bmp->db_agfree[agno] += n; 3553 3554 write_metapage(mp); 3555 3556 l0leaf++; 3557 p += nbperpage; 3558 3559 blkno += n; 3560 nblocks -= n; 3561 if (nblocks == 0) 3562 break; 3563 } /* for each dmap in a L0 */ 3564 3565 /* 3566 * build current L0 page from its leaves, and 3567 * initialize corresponding parent L1 leaf 3568 */ 3569 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i); 3570 write_metapage(l0mp); 3571 l0mp = NULL; 3572 3573 if (nblocks) 3574 l1leaf++; /* continue for next L0 */ 3575 else { 3576 /* more than 1 L0 ? */ 3577 if (j > 0) 3578 break; /* build L1 page */ 3579 else { 3580 /* summarize in global bmap page */ 3581 bmp->db_maxfreebud = *l1leaf; 3582 release_metapage(l1mp); 3583 release_metapage(l2mp); 3584 goto finalize; 3585 } 3586 } 3587 } /* for each L0 in a L1 */ 3588 3589 /* 3590 * build current L1 page from its leaves, and 3591 * initialize corresponding parent L2 leaf 3592 */ 3593 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j); 3594 write_metapage(l1mp); 3595 l1mp = NULL; 3596 3597 if (nblocks) 3598 l2leaf++; /* continue for next L1 */ 3599 else { 3600 /* more than 1 L1 ? */ 3601 if (k > 0) 3602 break; /* build L2 page */ 3603 else { 3604 /* summarize in global bmap page */ 3605 bmp->db_maxfreebud = *l2leaf; 3606 release_metapage(l2mp); 3607 goto finalize; 3608 } 3609 } 3610 } /* for each L1 in a L2 */ 3611 3612 jfs_error(ipbmap->i_sb, "function has not returned as expected\n"); 3613 errout: 3614 if (l0mp) 3615 release_metapage(l0mp); 3616 if (l1mp) 3617 release_metapage(l1mp); 3618 release_metapage(l2mp); 3619 return -EIO; 3620 3621 /* 3622 * finalize bmap control page 3623 */ 3624 finalize: 3625 3626 return 0; 3627 } 3628 3629 3630 /* 3631 * dbFinalizeBmap() 3632 */ 3633 void dbFinalizeBmap(struct inode *ipbmap) 3634 { 3635 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap; 3636 int actags, inactags, l2nl; 3637 s64 ag_rem, actfree, inactfree, avgfree; 3638 int i, n; 3639 3640 /* 3641 * finalize bmap control page 3642 */ 3643 //finalize: 3644 /* 3645 * compute db_agpref: preferred ag to allocate from 3646 * (the leftmost ag with average free space in it); 3647 */ 3648 //agpref: 3649 /* get the number of active ags and inactive ags */ 3650 actags = bmp->db_maxag + 1; 3651 inactags = bmp->db_numag - actags; 3652 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */ 3653 3654 /* determine how many blocks are in the inactive allocation 3655 * groups. in doing this, we must account for the fact that 3656 * the rightmost group might be a partial group (i.e. file 3657 * system size is not a multiple of the group size). 3658 */ 3659 inactfree = (inactags && ag_rem) ? 3660 ((inactags - 1) << bmp->db_agl2size) + ag_rem 3661 : inactags << bmp->db_agl2size; 3662 3663 /* determine how many free blocks are in the active 3664 * allocation groups plus the average number of free blocks 3665 * within the active ags. 3666 */ 3667 actfree = bmp->db_nfree - inactfree; 3668 avgfree = (u32) actfree / (u32) actags; 3669 3670 /* if the preferred allocation group has not average free space. 3671 * re-establish the preferred group as the leftmost 3672 * group with average free space. 3673 */ 3674 if (bmp->db_agfree[bmp->db_agpref] < avgfree) { 3675 for (bmp->db_agpref = 0; bmp->db_agpref < actags; 3676 bmp->db_agpref++) { 3677 if (bmp->db_agfree[bmp->db_agpref] >= avgfree) 3678 break; 3679 } 3680 if (bmp->db_agpref >= bmp->db_numag) { 3681 jfs_error(ipbmap->i_sb, 3682 "cannot find ag with average freespace\n"); 3683 } 3684 } 3685 3686 /* 3687 * compute db_aglevel, db_agheight, db_width, db_agstart: 3688 * an ag is covered in aglevel dmapctl summary tree, 3689 * at agheight level height (from leaf) with agwidth number of nodes 3690 * each, which starts at agstart index node of the smmary tree node 3691 * array; 3692 */ 3693 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize); 3694 l2nl = 3695 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL); 3696 bmp->db_agheight = l2nl >> 1; 3697 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1)); 3698 for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0; 3699 i--) { 3700 bmp->db_agstart += n; 3701 n <<= 2; 3702 } 3703 3704 } 3705 3706 3707 /* 3708 * NAME: dbInitDmap()/ujfs_idmap_page() 3709 * 3710 * FUNCTION: initialize working/persistent bitmap of the dmap page 3711 * for the specified number of blocks: 3712 * 3713 * at entry, the bitmaps had been initialized as free (ZEROS); 3714 * The number of blocks will only account for the actually 3715 * existing blocks. Blocks which don't actually exist in 3716 * the aggregate will be marked as allocated (ONES); 3717 * 3718 * PARAMETERS: 3719 * dp - pointer to page of map 3720 * nblocks - number of blocks this page 3721 * 3722 * RETURNS: NONE 3723 */ 3724 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks) 3725 { 3726 int blkno, w, b, r, nw, nb, i; 3727 3728 /* starting block number within the dmap */ 3729 blkno = Blkno & (BPERDMAP - 1); 3730 3731 if (blkno == 0) { 3732 dp->nblocks = dp->nfree = cpu_to_le32(nblocks); 3733 dp->start = cpu_to_le64(Blkno); 3734 3735 if (nblocks == BPERDMAP) { 3736 memset(&dp->wmap[0], 0, LPERDMAP * 4); 3737 memset(&dp->pmap[0], 0, LPERDMAP * 4); 3738 goto initTree; 3739 } 3740 } else { 3741 le32_add_cpu(&dp->nblocks, nblocks); 3742 le32_add_cpu(&dp->nfree, nblocks); 3743 } 3744 3745 /* word number containing start block number */ 3746 w = blkno >> L2DBWORD; 3747 3748 /* 3749 * free the bits corresponding to the block range (ZEROS): 3750 * note: not all bits of the first and last words may be contained 3751 * within the block range. 3752 */ 3753 for (r = nblocks; r > 0; r -= nb, blkno += nb) { 3754 /* number of bits preceding range to be freed in the word */ 3755 b = blkno & (DBWORD - 1); 3756 /* number of bits to free in the word */ 3757 nb = min(r, DBWORD - b); 3758 3759 /* is partial word to be freed ? */ 3760 if (nb < DBWORD) { 3761 /* free (set to 0) from the bitmap word */ 3762 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3763 >> b)); 3764 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb) 3765 >> b)); 3766 3767 /* skip the word freed */ 3768 w++; 3769 } else { 3770 /* free (set to 0) contiguous bitmap words */ 3771 nw = r >> L2DBWORD; 3772 memset(&dp->wmap[w], 0, nw * 4); 3773 memset(&dp->pmap[w], 0, nw * 4); 3774 3775 /* skip the words freed */ 3776 nb = nw << L2DBWORD; 3777 w += nw; 3778 } 3779 } 3780 3781 /* 3782 * mark bits following the range to be freed (non-existing 3783 * blocks) as allocated (ONES) 3784 */ 3785 3786 if (blkno == BPERDMAP) 3787 goto initTree; 3788 3789 /* the first word beyond the end of existing blocks */ 3790 w = blkno >> L2DBWORD; 3791 3792 /* does nblocks fall on a 32-bit boundary ? */ 3793 b = blkno & (DBWORD - 1); 3794 if (b) { 3795 /* mark a partial word allocated */ 3796 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b); 3797 w++; 3798 } 3799 3800 /* set the rest of the words in the page to allocated (ONES) */ 3801 for (i = w; i < LPERDMAP; i++) 3802 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES); 3803 3804 /* 3805 * init tree 3806 */ 3807 initTree: 3808 return (dbInitDmapTree(dp)); 3809 } 3810 3811 3812 /* 3813 * NAME: dbInitDmapTree()/ujfs_complete_dmap() 3814 * 3815 * FUNCTION: initialize summary tree of the specified dmap: 3816 * 3817 * at entry, bitmap of the dmap has been initialized; 3818 * 3819 * PARAMETERS: 3820 * dp - dmap to complete 3821 * blkno - starting block number for this dmap 3822 * treemax - will be filled in with max free for this dmap 3823 * 3824 * RETURNS: max free string at the root of the tree 3825 */ 3826 static int dbInitDmapTree(struct dmap * dp) 3827 { 3828 struct dmaptree *tp; 3829 s8 *cp; 3830 int i; 3831 3832 /* init fixed info of tree */ 3833 tp = &dp->tree; 3834 tp->nleafs = cpu_to_le32(LPERDMAP); 3835 tp->l2nleafs = cpu_to_le32(L2LPERDMAP); 3836 tp->leafidx = cpu_to_le32(LEAFIND); 3837 tp->height = cpu_to_le32(4); 3838 tp->budmin = BUDMIN; 3839 3840 /* init each leaf from corresponding wmap word: 3841 * note: leaf is set to NOFREE(-1) if all blocks of corresponding 3842 * bitmap word are allocated. 3843 */ 3844 cp = tp->stree + le32_to_cpu(tp->leafidx); 3845 for (i = 0; i < LPERDMAP; i++) 3846 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]); 3847 3848 /* build the dmap's binary buddy summary tree */ 3849 return (dbInitTree(tp)); 3850 } 3851 3852 3853 /* 3854 * NAME: dbInitTree()/ujfs_adjtree() 3855 * 3856 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl. 3857 * 3858 * at entry, the leaves of the tree has been initialized 3859 * from corresponding bitmap word or root of summary tree 3860 * of the child control page; 3861 * configure binary buddy system at the leaf level, then 3862 * bubble up the values of the leaf nodes up the tree. 3863 * 3864 * PARAMETERS: 3865 * cp - Pointer to the root of the tree 3866 * l2leaves- Number of leaf nodes as a power of 2 3867 * l2min - Number of blocks that can be covered by a leaf 3868 * as a power of 2 3869 * 3870 * RETURNS: max free string at the root of the tree 3871 */ 3872 static int dbInitTree(struct dmaptree * dtp) 3873 { 3874 int l2max, l2free, bsize, nextb, i; 3875 int child, parent, nparent; 3876 s8 *tp, *cp, *cp1; 3877 3878 tp = dtp->stree; 3879 3880 /* Determine the maximum free string possible for the leaves */ 3881 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin; 3882 3883 /* 3884 * configure the leaf level into binary buddy system 3885 * 3886 * Try to combine buddies starting with a buddy size of 1 3887 * (i.e. two leaves). At a buddy size of 1 two buddy leaves 3888 * can be combined if both buddies have a maximum free of l2min; 3889 * the combination will result in the left-most buddy leaf having 3890 * a maximum free of l2min+1. 3891 * After processing all buddies for a given size, process buddies 3892 * at the next higher buddy size (i.e. current size * 2) and 3893 * the next maximum free (current free + 1). 3894 * This continues until the maximum possible buddy combination 3895 * yields maximum free. 3896 */ 3897 for (l2free = dtp->budmin, bsize = 1; l2free < l2max; 3898 l2free++, bsize = nextb) { 3899 /* get next buddy size == current buddy pair size */ 3900 nextb = bsize << 1; 3901 3902 /* scan each adjacent buddy pair at current buddy size */ 3903 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx); 3904 i < le32_to_cpu(dtp->nleafs); 3905 i += nextb, cp += nextb) { 3906 /* coalesce if both adjacent buddies are max free */ 3907 if (*cp == l2free && *(cp + bsize) == l2free) { 3908 *cp = l2free + 1; /* left take right */ 3909 *(cp + bsize) = -1; /* right give left */ 3910 } 3911 } 3912 } 3913 3914 /* 3915 * bubble summary information of leaves up the tree. 3916 * 3917 * Starting at the leaf node level, the four nodes described by 3918 * the higher level parent node are compared for a maximum free and 3919 * this maximum becomes the value of the parent node. 3920 * when all lower level nodes are processed in this fashion then 3921 * move up to the next level (parent becomes a lower level node) and 3922 * continue the process for that level. 3923 */ 3924 for (child = le32_to_cpu(dtp->leafidx), 3925 nparent = le32_to_cpu(dtp->nleafs) >> 2; 3926 nparent > 0; nparent >>= 2, child = parent) { 3927 /* get index of 1st node of parent level */ 3928 parent = (child - 1) >> 2; 3929 3930 /* set the value of the parent node as the maximum 3931 * of the four nodes of the current level. 3932 */ 3933 for (i = 0, cp = tp + child, cp1 = tp + parent; 3934 i < nparent; i++, cp += 4, cp1++) 3935 *cp1 = TREEMAX(cp); 3936 } 3937 3938 return (*tp); 3939 } 3940 3941 3942 /* 3943 * dbInitDmapCtl() 3944 * 3945 * function: initialize dmapctl page 3946 */ 3947 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i) 3948 { /* start leaf index not covered by range */ 3949 s8 *cp; 3950 3951 dcp->nleafs = cpu_to_le32(LPERCTL); 3952 dcp->l2nleafs = cpu_to_le32(L2LPERCTL); 3953 dcp->leafidx = cpu_to_le32(CTLLEAFIND); 3954 dcp->height = cpu_to_le32(5); 3955 dcp->budmin = L2BPERDMAP + L2LPERCTL * level; 3956 3957 /* 3958 * initialize the leaves of current level that were not covered 3959 * by the specified input block range (i.e. the leaves have no 3960 * low level dmapctl or dmap). 3961 */ 3962 cp = &dcp->stree[CTLLEAFIND + i]; 3963 for (; i < LPERCTL; i++) 3964 *cp++ = NOFREE; 3965 3966 /* build the dmap's binary buddy summary tree */ 3967 return (dbInitTree((struct dmaptree *) dcp)); 3968 } 3969 3970 3971 /* 3972 * NAME: dbGetL2AGSize()/ujfs_getagl2size() 3973 * 3974 * FUNCTION: Determine log2(allocation group size) from aggregate size 3975 * 3976 * PARAMETERS: 3977 * nblocks - Number of blocks in aggregate 3978 * 3979 * RETURNS: log2(allocation group size) in aggregate blocks 3980 */ 3981 static int dbGetL2AGSize(s64 nblocks) 3982 { 3983 s64 sz; 3984 s64 m; 3985 int l2sz; 3986 3987 if (nblocks < BPERDMAP * MAXAG) 3988 return (L2BPERDMAP); 3989 3990 /* round up aggregate size to power of 2 */ 3991 m = ((u64) 1 << (64 - 1)); 3992 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) { 3993 if (m & nblocks) 3994 break; 3995 } 3996 3997 sz = (s64) 1 << l2sz; 3998 if (sz < nblocks) 3999 l2sz += 1; 4000 4001 /* agsize = roundupSize/max_number_of_ag */ 4002 return (l2sz - L2MAXAG); 4003 } 4004 4005 4006 /* 4007 * NAME: dbMapFileSizeToMapSize() 4008 * 4009 * FUNCTION: compute number of blocks the block allocation map file 4010 * can cover from the map file size; 4011 * 4012 * RETURNS: Number of blocks which can be covered by this block map file; 4013 */ 4014 4015 /* 4016 * maximum number of map pages at each level including control pages 4017 */ 4018 #define MAXL0PAGES (1 + LPERCTL) 4019 #define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES) 4020 4021 /* 4022 * convert number of map pages to the zero origin top dmapctl level 4023 */ 4024 #define BMAPPGTOLEV(npages) \ 4025 (((npages) <= 3 + MAXL0PAGES) ? 0 : \ 4026 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2) 4027 4028 s64 dbMapFileSizeToMapSize(struct inode * ipbmap) 4029 { 4030 struct super_block *sb = ipbmap->i_sb; 4031 s64 nblocks; 4032 s64 npages, ndmaps; 4033 int level, i; 4034 int complete, factor; 4035 4036 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize; 4037 npages = nblocks >> JFS_SBI(sb)->l2nbperpage; 4038 level = BMAPPGTOLEV(npages); 4039 4040 /* At each level, accumulate the number of dmap pages covered by 4041 * the number of full child levels below it; 4042 * repeat for the last incomplete child level. 4043 */ 4044 ndmaps = 0; 4045 npages--; /* skip the first global control page */ 4046 /* skip higher level control pages above top level covered by map */ 4047 npages -= (2 - level); 4048 npages--; /* skip top level's control page */ 4049 for (i = level; i >= 0; i--) { 4050 factor = 4051 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1); 4052 complete = (u32) npages / factor; 4053 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL : 4054 ((i == 1) ? LPERCTL : 1)); 4055 4056 /* pages in last/incomplete child */ 4057 npages = (u32) npages % factor; 4058 /* skip incomplete child's level control page */ 4059 npages--; 4060 } 4061 4062 /* convert the number of dmaps into the number of blocks 4063 * which can be covered by the dmaps; 4064 */ 4065 nblocks = ndmaps << L2BPERDMAP; 4066 4067 return (nblocks); 4068 } 4069