lcnalloc.c (32379B)
1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * lcnalloc.c - Cluster (de)allocation code. Part of the Linux-NTFS project. 4 * 5 * Copyright (c) 2004-2005 Anton Altaparmakov 6 */ 7 8#ifdef NTFS_RW 9 10#include <linux/pagemap.h> 11 12#include "lcnalloc.h" 13#include "debug.h" 14#include "bitmap.h" 15#include "inode.h" 16#include "volume.h" 17#include "attrib.h" 18#include "malloc.h" 19#include "aops.h" 20#include "ntfs.h" 21 22/** 23 * ntfs_cluster_free_from_rl_nolock - free clusters from runlist 24 * @vol: mounted ntfs volume on which to free the clusters 25 * @rl: runlist describing the clusters to free 26 * 27 * Free all the clusters described by the runlist @rl on the volume @vol. In 28 * the case of an error being returned, at least some of the clusters were not 29 * freed. 30 * 31 * Return 0 on success and -errno on error. 32 * 33 * Locking: - The volume lcn bitmap must be locked for writing on entry and is 34 * left locked on return. 35 */ 36int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol, 37 const runlist_element *rl) 38{ 39 struct inode *lcnbmp_vi = vol->lcnbmp_ino; 40 int ret = 0; 41 42 ntfs_debug("Entering."); 43 if (!rl) 44 return 0; 45 for (; rl->length; rl++) { 46 int err; 47 48 if (rl->lcn < 0) 49 continue; 50 err = ntfs_bitmap_clear_run(lcnbmp_vi, rl->lcn, rl->length); 51 if (unlikely(err && (!ret || ret == -ENOMEM) && ret != err)) 52 ret = err; 53 } 54 ntfs_debug("Done."); 55 return ret; 56} 57 58/** 59 * ntfs_cluster_alloc - allocate clusters on an ntfs volume 60 * @vol: mounted ntfs volume on which to allocate the clusters 61 * @start_vcn: vcn to use for the first allocated cluster 62 * @count: number of clusters to allocate 63 * @start_lcn: starting lcn at which to allocate the clusters (or -1 if none) 64 * @zone: zone from which to allocate the clusters 65 * @is_extension: if 'true', this is an attribute extension 66 * 67 * Allocate @count clusters preferably starting at cluster @start_lcn or at the 68 * current allocator position if @start_lcn is -1, on the mounted ntfs volume 69 * @vol. @zone is either DATA_ZONE for allocation of normal clusters or 70 * MFT_ZONE for allocation of clusters for the master file table, i.e. the 71 * $MFT/$DATA attribute. 72 * 73 * @start_vcn specifies the vcn of the first allocated cluster. This makes 74 * merging the resulting runlist with the old runlist easier. 75 * 76 * If @is_extension is 'true', the caller is allocating clusters to extend an 77 * attribute and if it is 'false', the caller is allocating clusters to fill a 78 * hole in an attribute. Practically the difference is that if @is_extension 79 * is 'true' the returned runlist will be terminated with LCN_ENOENT and if 80 * @is_extension is 'false' the runlist will be terminated with 81 * LCN_RL_NOT_MAPPED. 82 * 83 * You need to check the return value with IS_ERR(). If this is false, the 84 * function was successful and the return value is a runlist describing the 85 * allocated cluster(s). If IS_ERR() is true, the function failed and 86 * PTR_ERR() gives you the error code. 87 * 88 * Notes on the allocation algorithm 89 * ================================= 90 * 91 * There are two data zones. First is the area between the end of the mft zone 92 * and the end of the volume, and second is the area between the start of the 93 * volume and the start of the mft zone. On unmodified/standard NTFS 1.x 94 * volumes, the second data zone does not exist due to the mft zone being 95 * expanded to cover the start of the volume in order to reserve space for the 96 * mft bitmap attribute. 97 * 98 * This is not the prettiest function but the complexity stems from the need of 99 * implementing the mft vs data zoned approach and from the fact that we have 100 * access to the lcn bitmap in portions of up to 8192 bytes at a time, so we 101 * need to cope with crossing over boundaries of two buffers. Further, the 102 * fact that the allocator allows for caller supplied hints as to the location 103 * of where allocation should begin and the fact that the allocator keeps track 104 * of where in the data zones the next natural allocation should occur, 105 * contribute to the complexity of the function. But it should all be 106 * worthwhile, because this allocator should: 1) be a full implementation of 107 * the MFT zone approach used by Windows NT, 2) cause reduction in 108 * fragmentation, and 3) be speedy in allocations (the code is not optimized 109 * for speed, but the algorithm is, so further speed improvements are probably 110 * possible). 111 * 112 * FIXME: We should be monitoring cluster allocation and increment the MFT zone 113 * size dynamically but this is something for the future. We will just cause 114 * heavier fragmentation by not doing it and I am not even sure Windows would 115 * grow the MFT zone dynamically, so it might even be correct not to do this. 116 * The overhead in doing dynamic MFT zone expansion would be very large and 117 * unlikely worth the effort. (AIA) 118 * 119 * TODO: I have added in double the required zone position pointer wrap around 120 * logic which can be optimized to having only one of the two logic sets. 121 * However, having the double logic will work fine, but if we have only one of 122 * the sets and we get it wrong somewhere, then we get into trouble, so 123 * removing the duplicate logic requires _very_ careful consideration of _all_ 124 * possible code paths. So at least for now, I am leaving the double logic - 125 * better safe than sorry... (AIA) 126 * 127 * Locking: - The volume lcn bitmap must be unlocked on entry and is unlocked 128 * on return. 129 * - This function takes the volume lcn bitmap lock for writing and 130 * modifies the bitmap contents. 131 */ 132runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn, 133 const s64 count, const LCN start_lcn, 134 const NTFS_CLUSTER_ALLOCATION_ZONES zone, 135 const bool is_extension) 136{ 137 LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn; 138 LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size; 139 s64 clusters; 140 loff_t i_size; 141 struct inode *lcnbmp_vi; 142 runlist_element *rl = NULL; 143 struct address_space *mapping; 144 struct page *page = NULL; 145 u8 *buf, *byte; 146 int err = 0, rlpos, rlsize, buf_size; 147 u8 pass, done_zones, search_zone, need_writeback = 0, bit; 148 149 ntfs_debug("Entering for start_vcn 0x%llx, count 0x%llx, start_lcn " 150 "0x%llx, zone %s_ZONE.", (unsigned long long)start_vcn, 151 (unsigned long long)count, 152 (unsigned long long)start_lcn, 153 zone == MFT_ZONE ? "MFT" : "DATA"); 154 BUG_ON(!vol); 155 lcnbmp_vi = vol->lcnbmp_ino; 156 BUG_ON(!lcnbmp_vi); 157 BUG_ON(start_vcn < 0); 158 BUG_ON(count < 0); 159 BUG_ON(start_lcn < -1); 160 BUG_ON(zone < FIRST_ZONE); 161 BUG_ON(zone > LAST_ZONE); 162 163 /* Return NULL if @count is zero. */ 164 if (!count) 165 return NULL; 166 /* Take the lcnbmp lock for writing. */ 167 down_write(&vol->lcnbmp_lock); 168 /* 169 * If no specific @start_lcn was requested, use the current data zone 170 * position, otherwise use the requested @start_lcn but make sure it 171 * lies outside the mft zone. Also set done_zones to 0 (no zones done) 172 * and pass depending on whether we are starting inside a zone (1) or 173 * at the beginning of a zone (2). If requesting from the MFT_ZONE, 174 * we either start at the current position within the mft zone or at 175 * the specified position. If the latter is out of bounds then we start 176 * at the beginning of the MFT_ZONE. 177 */ 178 done_zones = 0; 179 pass = 1; 180 /* 181 * zone_start and zone_end are the current search range. search_zone 182 * is 1 for mft zone, 2 for data zone 1 (end of mft zone till end of 183 * volume) and 4 for data zone 2 (start of volume till start of mft 184 * zone). 185 */ 186 zone_start = start_lcn; 187 if (zone_start < 0) { 188 if (zone == DATA_ZONE) 189 zone_start = vol->data1_zone_pos; 190 else 191 zone_start = vol->mft_zone_pos; 192 if (!zone_start) { 193 /* 194 * Zone starts at beginning of volume which means a 195 * single pass is sufficient. 196 */ 197 pass = 2; 198 } 199 } else if (zone == DATA_ZONE && zone_start >= vol->mft_zone_start && 200 zone_start < vol->mft_zone_end) { 201 zone_start = vol->mft_zone_end; 202 /* 203 * Starting at beginning of data1_zone which means a single 204 * pass in this zone is sufficient. 205 */ 206 pass = 2; 207 } else if (zone == MFT_ZONE && (zone_start < vol->mft_zone_start || 208 zone_start >= vol->mft_zone_end)) { 209 zone_start = vol->mft_lcn; 210 if (!vol->mft_zone_end) 211 zone_start = 0; 212 /* 213 * Starting at beginning of volume which means a single pass 214 * is sufficient. 215 */ 216 pass = 2; 217 } 218 if (zone == MFT_ZONE) { 219 zone_end = vol->mft_zone_end; 220 search_zone = 1; 221 } else /* if (zone == DATA_ZONE) */ { 222 /* Skip searching the mft zone. */ 223 done_zones |= 1; 224 if (zone_start >= vol->mft_zone_end) { 225 zone_end = vol->nr_clusters; 226 search_zone = 2; 227 } else { 228 zone_end = vol->mft_zone_start; 229 search_zone = 4; 230 } 231 } 232 /* 233 * bmp_pos is the current bit position inside the bitmap. We use 234 * bmp_initial_pos to determine whether or not to do a zone switch. 235 */ 236 bmp_pos = bmp_initial_pos = zone_start; 237 238 /* Loop until all clusters are allocated, i.e. clusters == 0. */ 239 clusters = count; 240 rlpos = rlsize = 0; 241 mapping = lcnbmp_vi->i_mapping; 242 i_size = i_size_read(lcnbmp_vi); 243 while (1) { 244 ntfs_debug("Start of outer while loop: done_zones 0x%x, " 245 "search_zone %i, pass %i, zone_start 0x%llx, " 246 "zone_end 0x%llx, bmp_initial_pos 0x%llx, " 247 "bmp_pos 0x%llx, rlpos %i, rlsize %i.", 248 done_zones, search_zone, pass, 249 (unsigned long long)zone_start, 250 (unsigned long long)zone_end, 251 (unsigned long long)bmp_initial_pos, 252 (unsigned long long)bmp_pos, rlpos, rlsize); 253 /* Loop until we run out of free clusters. */ 254 last_read_pos = bmp_pos >> 3; 255 ntfs_debug("last_read_pos 0x%llx.", 256 (unsigned long long)last_read_pos); 257 if (last_read_pos > i_size) { 258 ntfs_debug("End of attribute reached. " 259 "Skipping to zone_pass_done."); 260 goto zone_pass_done; 261 } 262 if (likely(page)) { 263 if (need_writeback) { 264 ntfs_debug("Marking page dirty."); 265 flush_dcache_page(page); 266 set_page_dirty(page); 267 need_writeback = 0; 268 } 269 ntfs_unmap_page(page); 270 } 271 page = ntfs_map_page(mapping, last_read_pos >> 272 PAGE_SHIFT); 273 if (IS_ERR(page)) { 274 err = PTR_ERR(page); 275 ntfs_error(vol->sb, "Failed to map page."); 276 goto out; 277 } 278 buf_size = last_read_pos & ~PAGE_MASK; 279 buf = page_address(page) + buf_size; 280 buf_size = PAGE_SIZE - buf_size; 281 if (unlikely(last_read_pos + buf_size > i_size)) 282 buf_size = i_size - last_read_pos; 283 buf_size <<= 3; 284 lcn = bmp_pos & 7; 285 bmp_pos &= ~(LCN)7; 286 ntfs_debug("Before inner while loop: buf_size %i, lcn 0x%llx, " 287 "bmp_pos 0x%llx, need_writeback %i.", buf_size, 288 (unsigned long long)lcn, 289 (unsigned long long)bmp_pos, need_writeback); 290 while (lcn < buf_size && lcn + bmp_pos < zone_end) { 291 byte = buf + (lcn >> 3); 292 ntfs_debug("In inner while loop: buf_size %i, " 293 "lcn 0x%llx, bmp_pos 0x%llx, " 294 "need_writeback %i, byte ofs 0x%x, " 295 "*byte 0x%x.", buf_size, 296 (unsigned long long)lcn, 297 (unsigned long long)bmp_pos, 298 need_writeback, 299 (unsigned int)(lcn >> 3), 300 (unsigned int)*byte); 301 /* Skip full bytes. */ 302 if (*byte == 0xff) { 303 lcn = (lcn + 8) & ~(LCN)7; 304 ntfs_debug("Continuing while loop 1."); 305 continue; 306 } 307 bit = 1 << (lcn & 7); 308 ntfs_debug("bit 0x%x.", bit); 309 /* If the bit is already set, go onto the next one. */ 310 if (*byte & bit) { 311 lcn++; 312 ntfs_debug("Continuing while loop 2."); 313 continue; 314 } 315 /* 316 * Allocate more memory if needed, including space for 317 * the terminator element. 318 * ntfs_malloc_nofs() operates on whole pages only. 319 */ 320 if ((rlpos + 2) * sizeof(*rl) > rlsize) { 321 runlist_element *rl2; 322 323 ntfs_debug("Reallocating memory."); 324 if (!rl) 325 ntfs_debug("First free bit is at LCN " 326 "0x%llx.", 327 (unsigned long long) 328 (lcn + bmp_pos)); 329 rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE); 330 if (unlikely(!rl2)) { 331 err = -ENOMEM; 332 ntfs_error(vol->sb, "Failed to " 333 "allocate memory."); 334 goto out; 335 } 336 memcpy(rl2, rl, rlsize); 337 ntfs_free(rl); 338 rl = rl2; 339 rlsize += PAGE_SIZE; 340 ntfs_debug("Reallocated memory, rlsize 0x%x.", 341 rlsize); 342 } 343 /* Allocate the bitmap bit. */ 344 *byte |= bit; 345 /* We need to write this bitmap page to disk. */ 346 need_writeback = 1; 347 ntfs_debug("*byte 0x%x, need_writeback is set.", 348 (unsigned int)*byte); 349 /* 350 * Coalesce with previous run if adjacent LCNs. 351 * Otherwise, append a new run. 352 */ 353 ntfs_debug("Adding run (lcn 0x%llx, len 0x%llx), " 354 "prev_lcn 0x%llx, lcn 0x%llx, " 355 "bmp_pos 0x%llx, prev_run_len 0x%llx, " 356 "rlpos %i.", 357 (unsigned long long)(lcn + bmp_pos), 358 1ULL, (unsigned long long)prev_lcn, 359 (unsigned long long)lcn, 360 (unsigned long long)bmp_pos, 361 (unsigned long long)prev_run_len, 362 rlpos); 363 if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) { 364 ntfs_debug("Coalescing to run (lcn 0x%llx, " 365 "len 0x%llx).", 366 (unsigned long long) 367 rl[rlpos - 1].lcn, 368 (unsigned long long) 369 rl[rlpos - 1].length); 370 rl[rlpos - 1].length = ++prev_run_len; 371 ntfs_debug("Run now (lcn 0x%llx, len 0x%llx), " 372 "prev_run_len 0x%llx.", 373 (unsigned long long) 374 rl[rlpos - 1].lcn, 375 (unsigned long long) 376 rl[rlpos - 1].length, 377 (unsigned long long) 378 prev_run_len); 379 } else { 380 if (likely(rlpos)) { 381 ntfs_debug("Adding new run, (previous " 382 "run lcn 0x%llx, " 383 "len 0x%llx).", 384 (unsigned long long) 385 rl[rlpos - 1].lcn, 386 (unsigned long long) 387 rl[rlpos - 1].length); 388 rl[rlpos].vcn = rl[rlpos - 1].vcn + 389 prev_run_len; 390 } else { 391 ntfs_debug("Adding new run, is first " 392 "run."); 393 rl[rlpos].vcn = start_vcn; 394 } 395 rl[rlpos].lcn = prev_lcn = lcn + bmp_pos; 396 rl[rlpos].length = prev_run_len = 1; 397 rlpos++; 398 } 399 /* Done? */ 400 if (!--clusters) { 401 LCN tc; 402 /* 403 * Update the current zone position. Positions 404 * of already scanned zones have been updated 405 * during the respective zone switches. 406 */ 407 tc = lcn + bmp_pos + 1; 408 ntfs_debug("Done. Updating current zone " 409 "position, tc 0x%llx, " 410 "search_zone %i.", 411 (unsigned long long)tc, 412 search_zone); 413 switch (search_zone) { 414 case 1: 415 ntfs_debug("Before checks, " 416 "vol->mft_zone_pos " 417 "0x%llx.", 418 (unsigned long long) 419 vol->mft_zone_pos); 420 if (tc >= vol->mft_zone_end) { 421 vol->mft_zone_pos = 422 vol->mft_lcn; 423 if (!vol->mft_zone_end) 424 vol->mft_zone_pos = 0; 425 } else if ((bmp_initial_pos >= 426 vol->mft_zone_pos || 427 tc > vol->mft_zone_pos) 428 && tc >= vol->mft_lcn) 429 vol->mft_zone_pos = tc; 430 ntfs_debug("After checks, " 431 "vol->mft_zone_pos " 432 "0x%llx.", 433 (unsigned long long) 434 vol->mft_zone_pos); 435 break; 436 case 2: 437 ntfs_debug("Before checks, " 438 "vol->data1_zone_pos " 439 "0x%llx.", 440 (unsigned long long) 441 vol->data1_zone_pos); 442 if (tc >= vol->nr_clusters) 443 vol->data1_zone_pos = 444 vol->mft_zone_end; 445 else if ((bmp_initial_pos >= 446 vol->data1_zone_pos || 447 tc > vol->data1_zone_pos) 448 && tc >= vol->mft_zone_end) 449 vol->data1_zone_pos = tc; 450 ntfs_debug("After checks, " 451 "vol->data1_zone_pos " 452 "0x%llx.", 453 (unsigned long long) 454 vol->data1_zone_pos); 455 break; 456 case 4: 457 ntfs_debug("Before checks, " 458 "vol->data2_zone_pos " 459 "0x%llx.", 460 (unsigned long long) 461 vol->data2_zone_pos); 462 if (tc >= vol->mft_zone_start) 463 vol->data2_zone_pos = 0; 464 else if (bmp_initial_pos >= 465 vol->data2_zone_pos || 466 tc > vol->data2_zone_pos) 467 vol->data2_zone_pos = tc; 468 ntfs_debug("After checks, " 469 "vol->data2_zone_pos " 470 "0x%llx.", 471 (unsigned long long) 472 vol->data2_zone_pos); 473 break; 474 default: 475 BUG(); 476 } 477 ntfs_debug("Finished. Going to out."); 478 goto out; 479 } 480 lcn++; 481 } 482 bmp_pos += buf_size; 483 ntfs_debug("After inner while loop: buf_size 0x%x, lcn " 484 "0x%llx, bmp_pos 0x%llx, need_writeback %i.", 485 buf_size, (unsigned long long)lcn, 486 (unsigned long long)bmp_pos, need_writeback); 487 if (bmp_pos < zone_end) { 488 ntfs_debug("Continuing outer while loop, " 489 "bmp_pos 0x%llx, zone_end 0x%llx.", 490 (unsigned long long)bmp_pos, 491 (unsigned long long)zone_end); 492 continue; 493 } 494zone_pass_done: /* Finished with the current zone pass. */ 495 ntfs_debug("At zone_pass_done, pass %i.", pass); 496 if (pass == 1) { 497 /* 498 * Now do pass 2, scanning the first part of the zone 499 * we omitted in pass 1. 500 */ 501 pass = 2; 502 zone_end = zone_start; 503 switch (search_zone) { 504 case 1: /* mft_zone */ 505 zone_start = vol->mft_zone_start; 506 break; 507 case 2: /* data1_zone */ 508 zone_start = vol->mft_zone_end; 509 break; 510 case 4: /* data2_zone */ 511 zone_start = 0; 512 break; 513 default: 514 BUG(); 515 } 516 /* Sanity check. */ 517 if (zone_end < zone_start) 518 zone_end = zone_start; 519 bmp_pos = zone_start; 520 ntfs_debug("Continuing outer while loop, pass 2, " 521 "zone_start 0x%llx, zone_end 0x%llx, " 522 "bmp_pos 0x%llx.", 523 (unsigned long long)zone_start, 524 (unsigned long long)zone_end, 525 (unsigned long long)bmp_pos); 526 continue; 527 } /* pass == 2 */ 528done_zones_check: 529 ntfs_debug("At done_zones_check, search_zone %i, done_zones " 530 "before 0x%x, done_zones after 0x%x.", 531 search_zone, done_zones, 532 done_zones | search_zone); 533 done_zones |= search_zone; 534 if (done_zones < 7) { 535 ntfs_debug("Switching zone."); 536 /* Now switch to the next zone we haven't done yet. */ 537 pass = 1; 538 switch (search_zone) { 539 case 1: 540 ntfs_debug("Switching from mft zone to data1 " 541 "zone."); 542 /* Update mft zone position. */ 543 if (rlpos) { 544 LCN tc; 545 546 ntfs_debug("Before checks, " 547 "vol->mft_zone_pos " 548 "0x%llx.", 549 (unsigned long long) 550 vol->mft_zone_pos); 551 tc = rl[rlpos - 1].lcn + 552 rl[rlpos - 1].length; 553 if (tc >= vol->mft_zone_end) { 554 vol->mft_zone_pos = 555 vol->mft_lcn; 556 if (!vol->mft_zone_end) 557 vol->mft_zone_pos = 0; 558 } else if ((bmp_initial_pos >= 559 vol->mft_zone_pos || 560 tc > vol->mft_zone_pos) 561 && tc >= vol->mft_lcn) 562 vol->mft_zone_pos = tc; 563 ntfs_debug("After checks, " 564 "vol->mft_zone_pos " 565 "0x%llx.", 566 (unsigned long long) 567 vol->mft_zone_pos); 568 } 569 /* Switch from mft zone to data1 zone. */ 570switch_to_data1_zone: search_zone = 2; 571 zone_start = bmp_initial_pos = 572 vol->data1_zone_pos; 573 zone_end = vol->nr_clusters; 574 if (zone_start == vol->mft_zone_end) 575 pass = 2; 576 if (zone_start >= zone_end) { 577 vol->data1_zone_pos = zone_start = 578 vol->mft_zone_end; 579 pass = 2; 580 } 581 break; 582 case 2: 583 ntfs_debug("Switching from data1 zone to " 584 "data2 zone."); 585 /* Update data1 zone position. */ 586 if (rlpos) { 587 LCN tc; 588 589 ntfs_debug("Before checks, " 590 "vol->data1_zone_pos " 591 "0x%llx.", 592 (unsigned long long) 593 vol->data1_zone_pos); 594 tc = rl[rlpos - 1].lcn + 595 rl[rlpos - 1].length; 596 if (tc >= vol->nr_clusters) 597 vol->data1_zone_pos = 598 vol->mft_zone_end; 599 else if ((bmp_initial_pos >= 600 vol->data1_zone_pos || 601 tc > vol->data1_zone_pos) 602 && tc >= vol->mft_zone_end) 603 vol->data1_zone_pos = tc; 604 ntfs_debug("After checks, " 605 "vol->data1_zone_pos " 606 "0x%llx.", 607 (unsigned long long) 608 vol->data1_zone_pos); 609 } 610 /* Switch from data1 zone to data2 zone. */ 611 search_zone = 4; 612 zone_start = bmp_initial_pos = 613 vol->data2_zone_pos; 614 zone_end = vol->mft_zone_start; 615 if (!zone_start) 616 pass = 2; 617 if (zone_start >= zone_end) { 618 vol->data2_zone_pos = zone_start = 619 bmp_initial_pos = 0; 620 pass = 2; 621 } 622 break; 623 case 4: 624 ntfs_debug("Switching from data2 zone to " 625 "data1 zone."); 626 /* Update data2 zone position. */ 627 if (rlpos) { 628 LCN tc; 629 630 ntfs_debug("Before checks, " 631 "vol->data2_zone_pos " 632 "0x%llx.", 633 (unsigned long long) 634 vol->data2_zone_pos); 635 tc = rl[rlpos - 1].lcn + 636 rl[rlpos - 1].length; 637 if (tc >= vol->mft_zone_start) 638 vol->data2_zone_pos = 0; 639 else if (bmp_initial_pos >= 640 vol->data2_zone_pos || 641 tc > vol->data2_zone_pos) 642 vol->data2_zone_pos = tc; 643 ntfs_debug("After checks, " 644 "vol->data2_zone_pos " 645 "0x%llx.", 646 (unsigned long long) 647 vol->data2_zone_pos); 648 } 649 /* Switch from data2 zone to data1 zone. */ 650 goto switch_to_data1_zone; 651 default: 652 BUG(); 653 } 654 ntfs_debug("After zone switch, search_zone %i, " 655 "pass %i, bmp_initial_pos 0x%llx, " 656 "zone_start 0x%llx, zone_end 0x%llx.", 657 search_zone, pass, 658 (unsigned long long)bmp_initial_pos, 659 (unsigned long long)zone_start, 660 (unsigned long long)zone_end); 661 bmp_pos = zone_start; 662 if (zone_start == zone_end) { 663 ntfs_debug("Empty zone, going to " 664 "done_zones_check."); 665 /* Empty zone. Don't bother searching it. */ 666 goto done_zones_check; 667 } 668 ntfs_debug("Continuing outer while loop."); 669 continue; 670 } /* done_zones == 7 */ 671 ntfs_debug("All zones are finished."); 672 /* 673 * All zones are finished! If DATA_ZONE, shrink mft zone. If 674 * MFT_ZONE, we have really run out of space. 675 */ 676 mft_zone_size = vol->mft_zone_end - vol->mft_zone_start; 677 ntfs_debug("vol->mft_zone_start 0x%llx, vol->mft_zone_end " 678 "0x%llx, mft_zone_size 0x%llx.", 679 (unsigned long long)vol->mft_zone_start, 680 (unsigned long long)vol->mft_zone_end, 681 (unsigned long long)mft_zone_size); 682 if (zone == MFT_ZONE || mft_zone_size <= 0) { 683 ntfs_debug("No free clusters left, going to out."); 684 /* Really no more space left on device. */ 685 err = -ENOSPC; 686 goto out; 687 } /* zone == DATA_ZONE && mft_zone_size > 0 */ 688 ntfs_debug("Shrinking mft zone."); 689 zone_end = vol->mft_zone_end; 690 mft_zone_size >>= 1; 691 if (mft_zone_size > 0) 692 vol->mft_zone_end = vol->mft_zone_start + mft_zone_size; 693 else /* mft zone and data2 zone no longer exist. */ 694 vol->data2_zone_pos = vol->mft_zone_start = 695 vol->mft_zone_end = 0; 696 if (vol->mft_zone_pos >= vol->mft_zone_end) { 697 vol->mft_zone_pos = vol->mft_lcn; 698 if (!vol->mft_zone_end) 699 vol->mft_zone_pos = 0; 700 } 701 bmp_pos = zone_start = bmp_initial_pos = 702 vol->data1_zone_pos = vol->mft_zone_end; 703 search_zone = 2; 704 pass = 2; 705 done_zones &= ~2; 706 ntfs_debug("After shrinking mft zone, mft_zone_size 0x%llx, " 707 "vol->mft_zone_start 0x%llx, " 708 "vol->mft_zone_end 0x%llx, " 709 "vol->mft_zone_pos 0x%llx, search_zone 2, " 710 "pass 2, dones_zones 0x%x, zone_start 0x%llx, " 711 "zone_end 0x%llx, vol->data1_zone_pos 0x%llx, " 712 "continuing outer while loop.", 713 (unsigned long long)mft_zone_size, 714 (unsigned long long)vol->mft_zone_start, 715 (unsigned long long)vol->mft_zone_end, 716 (unsigned long long)vol->mft_zone_pos, 717 done_zones, (unsigned long long)zone_start, 718 (unsigned long long)zone_end, 719 (unsigned long long)vol->data1_zone_pos); 720 } 721 ntfs_debug("After outer while loop."); 722out: 723 ntfs_debug("At out."); 724 /* Add runlist terminator element. */ 725 if (likely(rl)) { 726 rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length; 727 rl[rlpos].lcn = is_extension ? LCN_ENOENT : LCN_RL_NOT_MAPPED; 728 rl[rlpos].length = 0; 729 } 730 if (likely(page && !IS_ERR(page))) { 731 if (need_writeback) { 732 ntfs_debug("Marking page dirty."); 733 flush_dcache_page(page); 734 set_page_dirty(page); 735 need_writeback = 0; 736 } 737 ntfs_unmap_page(page); 738 } 739 if (likely(!err)) { 740 up_write(&vol->lcnbmp_lock); 741 ntfs_debug("Done."); 742 return rl; 743 } 744 ntfs_error(vol->sb, "Failed to allocate clusters, aborting " 745 "(error %i).", err); 746 if (rl) { 747 int err2; 748 749 if (err == -ENOSPC) 750 ntfs_debug("Not enough space to complete allocation, " 751 "err -ENOSPC, first free lcn 0x%llx, " 752 "could allocate up to 0x%llx " 753 "clusters.", 754 (unsigned long long)rl[0].lcn, 755 (unsigned long long)(count - clusters)); 756 /* Deallocate all allocated clusters. */ 757 ntfs_debug("Attempting rollback..."); 758 err2 = ntfs_cluster_free_from_rl_nolock(vol, rl); 759 if (err2) { 760 ntfs_error(vol->sb, "Failed to rollback (error %i). " 761 "Leaving inconsistent metadata! " 762 "Unmount and run chkdsk.", err2); 763 NVolSetErrors(vol); 764 } 765 /* Free the runlist. */ 766 ntfs_free(rl); 767 } else if (err == -ENOSPC) 768 ntfs_debug("No space left at all, err = -ENOSPC, first free " 769 "lcn = 0x%llx.", 770 (long long)vol->data1_zone_pos); 771 up_write(&vol->lcnbmp_lock); 772 return ERR_PTR(err); 773} 774 775/** 776 * __ntfs_cluster_free - free clusters on an ntfs volume 777 * @ni: ntfs inode whose runlist describes the clusters to free 778 * @start_vcn: vcn in the runlist of @ni at which to start freeing clusters 779 * @count: number of clusters to free or -1 for all clusters 780 * @ctx: active attribute search context if present or NULL if not 781 * @is_rollback: true if this is a rollback operation 782 * 783 * Free @count clusters starting at the cluster @start_vcn in the runlist 784 * described by the vfs inode @ni. 785 * 786 * If @count is -1, all clusters from @start_vcn to the end of the runlist are 787 * deallocated. Thus, to completely free all clusters in a runlist, use 788 * @start_vcn = 0 and @count = -1. 789 * 790 * If @ctx is specified, it is an active search context of @ni and its base mft 791 * record. This is needed when __ntfs_cluster_free() encounters unmapped 792 * runlist fragments and allows their mapping. If you do not have the mft 793 * record mapped, you can specify @ctx as NULL and __ntfs_cluster_free() will 794 * perform the necessary mapping and unmapping. 795 * 796 * Note, __ntfs_cluster_free() saves the state of @ctx on entry and restores it 797 * before returning. Thus, @ctx will be left pointing to the same attribute on 798 * return as on entry. However, the actual pointers in @ctx may point to 799 * different memory locations on return, so you must remember to reset any 800 * cached pointers from the @ctx, i.e. after the call to __ntfs_cluster_free(), 801 * you will probably want to do: 802 * m = ctx->mrec; 803 * a = ctx->attr; 804 * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that 805 * you cache ctx->mrec in a variable @m of type MFT_RECORD *. 806 * 807 * @is_rollback should always be 'false', it is for internal use to rollback 808 * errors. You probably want to use ntfs_cluster_free() instead. 809 * 810 * Note, __ntfs_cluster_free() does not modify the runlist, so you have to 811 * remove from the runlist or mark sparse the freed runs later. 812 * 813 * Return the number of deallocated clusters (not counting sparse ones) on 814 * success and -errno on error. 815 * 816 * WARNING: If @ctx is supplied, regardless of whether success or failure is 817 * returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx 818 * is no longer valid, i.e. you need to either call 819 * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it. 820 * In that case PTR_ERR(@ctx->mrec) will give you the error code for 821 * why the mapping of the old inode failed. 822 * 823 * Locking: - The runlist described by @ni must be locked for writing on entry 824 * and is locked on return. Note the runlist may be modified when 825 * needed runlist fragments need to be mapped. 826 * - The volume lcn bitmap must be unlocked on entry and is unlocked 827 * on return. 828 * - This function takes the volume lcn bitmap lock for writing and 829 * modifies the bitmap contents. 830 * - If @ctx is NULL, the base mft record of @ni must not be mapped on 831 * entry and it will be left unmapped on return. 832 * - If @ctx is not NULL, the base mft record must be mapped on entry 833 * and it will be left mapped on return. 834 */ 835s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count, 836 ntfs_attr_search_ctx *ctx, const bool is_rollback) 837{ 838 s64 delta, to_free, total_freed, real_freed; 839 ntfs_volume *vol; 840 struct inode *lcnbmp_vi; 841 runlist_element *rl; 842 int err; 843 844 BUG_ON(!ni); 845 ntfs_debug("Entering for i_ino 0x%lx, start_vcn 0x%llx, count " 846 "0x%llx.%s", ni->mft_no, (unsigned long long)start_vcn, 847 (unsigned long long)count, 848 is_rollback ? " (rollback)" : ""); 849 vol = ni->vol; 850 lcnbmp_vi = vol->lcnbmp_ino; 851 BUG_ON(!lcnbmp_vi); 852 BUG_ON(start_vcn < 0); 853 BUG_ON(count < -1); 854 /* 855 * Lock the lcn bitmap for writing but only if not rolling back. We 856 * must hold the lock all the way including through rollback otherwise 857 * rollback is not possible because once we have cleared a bit and 858 * dropped the lock, anyone could have set the bit again, thus 859 * allocating the cluster for another use. 860 */ 861 if (likely(!is_rollback)) 862 down_write(&vol->lcnbmp_lock); 863 864 total_freed = real_freed = 0; 865 866 rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, ctx); 867 if (IS_ERR(rl)) { 868 if (!is_rollback) 869 ntfs_error(vol->sb, "Failed to find first runlist " 870 "element (error %li), aborting.", 871 PTR_ERR(rl)); 872 err = PTR_ERR(rl); 873 goto err_out; 874 } 875 if (unlikely(rl->lcn < LCN_HOLE)) { 876 if (!is_rollback) 877 ntfs_error(vol->sb, "First runlist element has " 878 "invalid lcn, aborting."); 879 err = -EIO; 880 goto err_out; 881 } 882 /* Find the starting cluster inside the run that needs freeing. */ 883 delta = start_vcn - rl->vcn; 884 885 /* The number of clusters in this run that need freeing. */ 886 to_free = rl->length - delta; 887 if (count >= 0 && to_free > count) 888 to_free = count; 889 890 if (likely(rl->lcn >= 0)) { 891 /* Do the actual freeing of the clusters in this run. */ 892 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn + delta, 893 to_free, likely(!is_rollback) ? 0 : 1); 894 if (unlikely(err)) { 895 if (!is_rollback) 896 ntfs_error(vol->sb, "Failed to clear first run " 897 "(error %i), aborting.", err); 898 goto err_out; 899 } 900 /* We have freed @to_free real clusters. */ 901 real_freed = to_free; 902 }; 903 /* Go to the next run and adjust the number of clusters left to free. */ 904 ++rl; 905 if (count >= 0) 906 count -= to_free; 907 908 /* Keep track of the total "freed" clusters, including sparse ones. */ 909 total_freed = to_free; 910 /* 911 * Loop over the remaining runs, using @count as a capping value, and 912 * free them. 913 */ 914 for (; rl->length && count != 0; ++rl) { 915 if (unlikely(rl->lcn < LCN_HOLE)) { 916 VCN vcn; 917 918 /* Attempt to map runlist. */ 919 vcn = rl->vcn; 920 rl = ntfs_attr_find_vcn_nolock(ni, vcn, ctx); 921 if (IS_ERR(rl)) { 922 err = PTR_ERR(rl); 923 if (!is_rollback) 924 ntfs_error(vol->sb, "Failed to map " 925 "runlist fragment or " 926 "failed to find " 927 "subsequent runlist " 928 "element."); 929 goto err_out; 930 } 931 if (unlikely(rl->lcn < LCN_HOLE)) { 932 if (!is_rollback) 933 ntfs_error(vol->sb, "Runlist element " 934 "has invalid lcn " 935 "(0x%llx).", 936 (unsigned long long) 937 rl->lcn); 938 err = -EIO; 939 goto err_out; 940 } 941 } 942 /* The number of clusters in this run that need freeing. */ 943 to_free = rl->length; 944 if (count >= 0 && to_free > count) 945 to_free = count; 946 947 if (likely(rl->lcn >= 0)) { 948 /* Do the actual freeing of the clusters in the run. */ 949 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn, 950 to_free, likely(!is_rollback) ? 0 : 1); 951 if (unlikely(err)) { 952 if (!is_rollback) 953 ntfs_error(vol->sb, "Failed to clear " 954 "subsequent run."); 955 goto err_out; 956 } 957 /* We have freed @to_free real clusters. */ 958 real_freed += to_free; 959 } 960 /* Adjust the number of clusters left to free. */ 961 if (count >= 0) 962 count -= to_free; 963 964 /* Update the total done clusters. */ 965 total_freed += to_free; 966 } 967 if (likely(!is_rollback)) 968 up_write(&vol->lcnbmp_lock); 969 970 BUG_ON(count > 0); 971 972 /* We are done. Return the number of actually freed clusters. */ 973 ntfs_debug("Done."); 974 return real_freed; 975err_out: 976 if (is_rollback) 977 return err; 978 /* If no real clusters were freed, no need to rollback. */ 979 if (!real_freed) { 980 up_write(&vol->lcnbmp_lock); 981 return err; 982 } 983 /* 984 * Attempt to rollback and if that succeeds just return the error code. 985 * If rollback fails, set the volume errors flag, emit an error 986 * message, and return the error code. 987 */ 988 delta = __ntfs_cluster_free(ni, start_vcn, total_freed, ctx, true); 989 if (delta < 0) { 990 ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving " 991 "inconsistent metadata! Unmount and run " 992 "chkdsk.", (int)delta); 993 NVolSetErrors(vol); 994 } 995 up_write(&vol->lcnbmp_lock); 996 ntfs_error(vol->sb, "Aborting (error %i).", err); 997 return err; 998} 999 1000#endif /* NTFS_RW */