1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2017 Oracle. All Rights Reserved. 4 * 5 * Author: Darrick J. Wong <darrick.wong@oracle.com> 6 */ 7 #include "ext4.h" 8 #include <linux/fsmap.h> 9 #include "fsmap.h" 10 #include "mballoc.h" 11 #include <linux/sort.h> 12 #include <linux/list_sort.h> 13 #include <trace/events/ext4.h> 14 15 /* Convert an ext4_fsmap to an fsmap. */ 16 void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest, 17 struct ext4_fsmap *src) 18 { 19 dest->fmr_device = src->fmr_device; 20 dest->fmr_flags = src->fmr_flags; 21 dest->fmr_physical = src->fmr_physical << sb->s_blocksize_bits; 22 dest->fmr_owner = src->fmr_owner; 23 dest->fmr_offset = 0; 24 dest->fmr_length = src->fmr_length << sb->s_blocksize_bits; 25 dest->fmr_reserved[0] = 0; 26 dest->fmr_reserved[1] = 0; 27 dest->fmr_reserved[2] = 0; 28 } 29 30 /* Convert an fsmap to an ext4_fsmap. */ 31 void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest, 32 struct fsmap *src) 33 { 34 dest->fmr_device = src->fmr_device; 35 dest->fmr_flags = src->fmr_flags; 36 dest->fmr_physical = src->fmr_physical >> sb->s_blocksize_bits; 37 dest->fmr_owner = src->fmr_owner; 38 dest->fmr_length = src->fmr_length >> sb->s_blocksize_bits; 39 } 40 41 /* getfsmap query state */ 42 struct ext4_getfsmap_info { 43 struct ext4_fsmap_head *gfi_head; 44 ext4_fsmap_format_t gfi_formatter; /* formatting fn */ 45 void *gfi_format_arg;/* format buffer */ 46 ext4_fsblk_t gfi_next_fsblk; /* next fsblock we expect */ 47 u32 gfi_dev; /* device id */ 48 ext4_group_t gfi_agno; /* bg number, if applicable */ 49 struct ext4_fsmap gfi_low; /* low rmap key */ 50 struct ext4_fsmap gfi_high; /* high rmap key */ 51 struct ext4_fsmap gfi_lastfree; /* free ext at end of last bg */ 52 struct list_head gfi_meta_list; /* fixed metadata list */ 53 bool gfi_last; /* last extent? */ 54 }; 55 56 /* Associate a device with a getfsmap handler. */ 57 struct ext4_getfsmap_dev { 58 int (*gfd_fn)(struct super_block *sb, 59 struct ext4_fsmap *keys, 60 struct ext4_getfsmap_info *info); 61 u32 gfd_dev; 62 }; 63 64 /* Compare two getfsmap device handlers. */ 65 static int ext4_getfsmap_dev_compare(const void *p1, const void *p2) 66 { 67 const struct ext4_getfsmap_dev *d1 = p1; 68 const struct ext4_getfsmap_dev *d2 = p2; 69 70 return d1->gfd_dev - d2->gfd_dev; 71 } 72 73 /* Compare a record against our starting point */ 74 static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info, 75 struct ext4_fsmap *rec) 76 { 77 return rec->fmr_physical < info->gfi_low.fmr_physical; 78 } 79 80 /* 81 * Format a reverse mapping for getfsmap, having translated rm_startblock 82 * into the appropriate daddr units. 83 */ 84 static int ext4_getfsmap_helper(struct super_block *sb, 85 struct ext4_getfsmap_info *info, 86 struct ext4_fsmap *rec) 87 { 88 struct ext4_fsmap fmr; 89 struct ext4_sb_info *sbi = EXT4_SB(sb); 90 ext4_fsblk_t rec_fsblk = rec->fmr_physical; 91 ext4_group_t agno; 92 ext4_grpblk_t cno; 93 int error; 94 95 if (fatal_signal_pending(current)) 96 return -EINTR; 97 98 /* 99 * Filter out records that start before our startpoint, if the 100 * caller requested that. 101 */ 102 if (ext4_getfsmap_rec_before_low_key(info, rec)) { 103 rec_fsblk += rec->fmr_length; 104 if (info->gfi_next_fsblk < rec_fsblk) 105 info->gfi_next_fsblk = rec_fsblk; 106 return EXT4_QUERY_RANGE_CONTINUE; 107 } 108 109 /* Are we just counting mappings? */ 110 if (info->gfi_head->fmh_count == 0) { 111 if (info->gfi_head->fmh_entries == UINT_MAX) 112 return EXT4_QUERY_RANGE_ABORT; 113 114 if (rec_fsblk > info->gfi_next_fsblk) 115 info->gfi_head->fmh_entries++; 116 117 if (info->gfi_last) 118 return EXT4_QUERY_RANGE_CONTINUE; 119 120 info->gfi_head->fmh_entries++; 121 122 rec_fsblk += rec->fmr_length; 123 if (info->gfi_next_fsblk < rec_fsblk) 124 info->gfi_next_fsblk = rec_fsblk; 125 return EXT4_QUERY_RANGE_CONTINUE; 126 } 127 128 /* 129 * If the record starts past the last physical block we saw, 130 * then we've found a gap. Report the gap as being owned by 131 * whatever the caller specified is the missing owner. 132 */ 133 if (rec_fsblk > info->gfi_next_fsblk) { 134 if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count) 135 return EXT4_QUERY_RANGE_ABORT; 136 137 ext4_get_group_no_and_offset(sb, info->gfi_next_fsblk, 138 &agno, &cno); 139 trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, 140 EXT4_C2B(sbi, cno), 141 rec_fsblk - info->gfi_next_fsblk, 142 EXT4_FMR_OWN_UNKNOWN); 143 144 fmr.fmr_device = info->gfi_dev; 145 fmr.fmr_physical = info->gfi_next_fsblk; 146 fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN; 147 fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk; 148 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER; 149 error = info->gfi_formatter(&fmr, info->gfi_format_arg); 150 if (error) 151 return error; 152 info->gfi_head->fmh_entries++; 153 } 154 155 if (info->gfi_last) 156 goto out; 157 158 /* Fill out the extent we found */ 159 if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count) 160 return EXT4_QUERY_RANGE_ABORT; 161 162 ext4_get_group_no_and_offset(sb, rec_fsblk, &agno, &cno); 163 trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno), 164 rec->fmr_length, rec->fmr_owner); 165 166 fmr.fmr_device = info->gfi_dev; 167 fmr.fmr_physical = rec_fsblk; 168 fmr.fmr_owner = rec->fmr_owner; 169 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER; 170 fmr.fmr_length = rec->fmr_length; 171 error = info->gfi_formatter(&fmr, info->gfi_format_arg); 172 if (error) 173 return error; 174 info->gfi_head->fmh_entries++; 175 176 out: 177 rec_fsblk += rec->fmr_length; 178 if (info->gfi_next_fsblk < rec_fsblk) 179 info->gfi_next_fsblk = rec_fsblk; 180 return EXT4_QUERY_RANGE_CONTINUE; 181 } 182 183 static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr) 184 { 185 return fmr->fmr_physical + fmr->fmr_length; 186 } 187 188 /* Transform a blockgroup's free record into a fsmap */ 189 static int ext4_getfsmap_datadev_helper(struct super_block *sb, 190 ext4_group_t agno, ext4_grpblk_t start, 191 ext4_grpblk_t len, void *priv) 192 { 193 struct ext4_fsmap irec; 194 struct ext4_getfsmap_info *info = priv; 195 struct ext4_fsmap *p; 196 struct ext4_fsmap *tmp; 197 struct ext4_sb_info *sbi = EXT4_SB(sb); 198 ext4_fsblk_t fsb; 199 ext4_fsblk_t fslen; 200 int error; 201 202 fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno)); 203 fslen = EXT4_C2B(sbi, len); 204 205 /* If the retained free extent record is set... */ 206 if (info->gfi_lastfree.fmr_owner) { 207 /* ...and abuts this one, lengthen it and return. */ 208 if (ext4_fsmap_next_pblk(&info->gfi_lastfree) == fsb) { 209 info->gfi_lastfree.fmr_length += fslen; 210 return 0; 211 } 212 213 /* 214 * There's a gap between the two free extents; emit the 215 * retained extent prior to merging the meta_list. 216 */ 217 error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree); 218 if (error) 219 return error; 220 info->gfi_lastfree.fmr_owner = 0; 221 } 222 223 /* Merge in any relevant extents from the meta_list */ 224 list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) { 225 if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) { 226 list_del(&p->fmr_list); 227 kfree(p); 228 } else if (p->fmr_physical < fsb) { 229 error = ext4_getfsmap_helper(sb, info, p); 230 if (error) 231 return error; 232 233 list_del(&p->fmr_list); 234 kfree(p); 235 } 236 } 237 238 irec.fmr_device = 0; 239 irec.fmr_physical = fsb; 240 irec.fmr_length = fslen; 241 irec.fmr_owner = EXT4_FMR_OWN_FREE; 242 irec.fmr_flags = 0; 243 244 /* If this is a free extent at the end of a bg, buffer it. */ 245 if (ext4_fsmap_next_pblk(&irec) == 246 ext4_group_first_block_no(sb, agno + 1)) { 247 info->gfi_lastfree = irec; 248 return 0; 249 } 250 251 /* Otherwise, emit it */ 252 return ext4_getfsmap_helper(sb, info, &irec); 253 } 254 255 /* Execute a getfsmap query against the log device. */ 256 static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys, 257 struct ext4_getfsmap_info *info) 258 { 259 journal_t *journal = EXT4_SB(sb)->s_journal; 260 struct ext4_fsmap irec; 261 262 /* Set up search keys */ 263 info->gfi_low = keys[0]; 264 info->gfi_low.fmr_length = 0; 265 266 memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high)); 267 268 trace_ext4_fsmap_low_key(sb, info->gfi_dev, 0, 269 info->gfi_low.fmr_physical, 270 info->gfi_low.fmr_length, 271 info->gfi_low.fmr_owner); 272 273 trace_ext4_fsmap_high_key(sb, info->gfi_dev, 0, 274 info->gfi_high.fmr_physical, 275 info->gfi_high.fmr_length, 276 info->gfi_high.fmr_owner); 277 278 if (keys[0].fmr_physical > 0) 279 return 0; 280 281 /* Fabricate an rmap entry for the external log device. */ 282 irec.fmr_physical = journal->j_blk_offset; 283 irec.fmr_length = journal->j_total_len; 284 irec.fmr_owner = EXT4_FMR_OWN_LOG; 285 irec.fmr_flags = 0; 286 287 return ext4_getfsmap_helper(sb, info, &irec); 288 } 289 290 /* Helper to fill out an ext4_fsmap. */ 291 static inline int ext4_getfsmap_fill(struct list_head *meta_list, 292 ext4_fsblk_t fsb, ext4_fsblk_t len, 293 uint64_t owner) 294 { 295 struct ext4_fsmap *fsm; 296 297 fsm = kmalloc(sizeof(*fsm), GFP_NOFS); 298 if (!fsm) 299 return -ENOMEM; 300 fsm->fmr_device = 0; 301 fsm->fmr_flags = 0; 302 fsm->fmr_physical = fsb; 303 fsm->fmr_owner = owner; 304 fsm->fmr_length = len; 305 list_add_tail(&fsm->fmr_list, meta_list); 306 307 return 0; 308 } 309 310 /* 311 * This function returns the number of file system metadata blocks at 312 * the beginning of a block group, including the reserved gdt blocks. 313 */ 314 static unsigned int ext4_getfsmap_find_sb(struct super_block *sb, 315 ext4_group_t agno, 316 struct list_head *meta_list) 317 { 318 struct ext4_sb_info *sbi = EXT4_SB(sb); 319 ext4_fsblk_t fsb = ext4_group_first_block_no(sb, agno); 320 ext4_fsblk_t len; 321 unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg); 322 unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb); 323 int error; 324 325 /* Record the superblock. */ 326 if (ext4_bg_has_super(sb, agno)) { 327 error = ext4_getfsmap_fill(meta_list, fsb, 1, EXT4_FMR_OWN_FS); 328 if (error) 329 return error; 330 fsb++; 331 } 332 333 /* Record the group descriptors. */ 334 len = ext4_bg_num_gdb(sb, agno); 335 if (!len) 336 return 0; 337 error = ext4_getfsmap_fill(meta_list, fsb, len, 338 EXT4_FMR_OWN_GDT); 339 if (error) 340 return error; 341 fsb += len; 342 343 /* Reserved GDT blocks */ 344 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) { 345 len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); 346 error = ext4_getfsmap_fill(meta_list, fsb, len, 347 EXT4_FMR_OWN_RESV_GDT); 348 if (error) 349 return error; 350 } 351 352 return 0; 353 } 354 355 /* Compare two fsmap items. */ 356 static int ext4_getfsmap_compare(void *priv, 357 const struct list_head *a, 358 const struct list_head *b) 359 { 360 struct ext4_fsmap *fa; 361 struct ext4_fsmap *fb; 362 363 fa = container_of(a, struct ext4_fsmap, fmr_list); 364 fb = container_of(b, struct ext4_fsmap, fmr_list); 365 if (fa->fmr_physical < fb->fmr_physical) 366 return -1; 367 else if (fa->fmr_physical > fb->fmr_physical) 368 return 1; 369 return 0; 370 } 371 372 /* Merge adjacent extents of fixed metadata. */ 373 static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list) 374 { 375 struct ext4_fsmap *p; 376 struct ext4_fsmap *prev = NULL; 377 struct ext4_fsmap *tmp; 378 379 list_for_each_entry_safe(p, tmp, meta_list, fmr_list) { 380 if (!prev) { 381 prev = p; 382 continue; 383 } 384 385 if (prev->fmr_owner == p->fmr_owner && 386 prev->fmr_physical + prev->fmr_length == p->fmr_physical) { 387 prev->fmr_length += p->fmr_length; 388 list_del(&p->fmr_list); 389 kfree(p); 390 } else 391 prev = p; 392 } 393 } 394 395 /* Free a list of fixed metadata. */ 396 static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list) 397 { 398 struct ext4_fsmap *p; 399 struct ext4_fsmap *tmp; 400 401 list_for_each_entry_safe(p, tmp, meta_list, fmr_list) { 402 list_del(&p->fmr_list); 403 kfree(p); 404 } 405 } 406 407 /* Find all the fixed metadata in the filesystem. */ 408 static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb, 409 struct list_head *meta_list) 410 { 411 struct ext4_group_desc *gdp; 412 ext4_group_t agno; 413 int error; 414 415 INIT_LIST_HEAD(meta_list); 416 417 /* Collect everything. */ 418 for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) { 419 gdp = ext4_get_group_desc(sb, agno, NULL); 420 if (!gdp) { 421 error = -EFSCORRUPTED; 422 goto err; 423 } 424 425 /* Superblock & GDT */ 426 error = ext4_getfsmap_find_sb(sb, agno, meta_list); 427 if (error) 428 goto err; 429 430 /* Block bitmap */ 431 error = ext4_getfsmap_fill(meta_list, 432 ext4_block_bitmap(sb, gdp), 1, 433 EXT4_FMR_OWN_BLKBM); 434 if (error) 435 goto err; 436 437 /* Inode bitmap */ 438 error = ext4_getfsmap_fill(meta_list, 439 ext4_inode_bitmap(sb, gdp), 1, 440 EXT4_FMR_OWN_INOBM); 441 if (error) 442 goto err; 443 444 /* Inodes */ 445 error = ext4_getfsmap_fill(meta_list, 446 ext4_inode_table(sb, gdp), 447 EXT4_SB(sb)->s_itb_per_group, 448 EXT4_FMR_OWN_INODES); 449 if (error) 450 goto err; 451 } 452 453 /* Sort the list */ 454 list_sort(NULL, meta_list, ext4_getfsmap_compare); 455 456 /* Merge adjacent extents */ 457 ext4_getfsmap_merge_fixed_metadata(meta_list); 458 459 return 0; 460 err: 461 ext4_getfsmap_free_fixed_metadata(meta_list); 462 return error; 463 } 464 465 /* Execute a getfsmap query against the buddy bitmaps */ 466 static int ext4_getfsmap_datadev(struct super_block *sb, 467 struct ext4_fsmap *keys, 468 struct ext4_getfsmap_info *info) 469 { 470 struct ext4_sb_info *sbi = EXT4_SB(sb); 471 ext4_fsblk_t start_fsb; 472 ext4_fsblk_t end_fsb; 473 ext4_fsblk_t bofs; 474 ext4_fsblk_t eofs; 475 ext4_group_t start_ag; 476 ext4_group_t end_ag; 477 ext4_grpblk_t first_cluster; 478 ext4_grpblk_t last_cluster; 479 int error = 0; 480 481 bofs = le32_to_cpu(sbi->s_es->s_first_data_block); 482 eofs = ext4_blocks_count(sbi->s_es); 483 if (keys[0].fmr_physical >= eofs) 484 return 0; 485 else if (keys[0].fmr_physical < bofs) 486 keys[0].fmr_physical = bofs; 487 if (keys[1].fmr_physical >= eofs) 488 keys[1].fmr_physical = eofs - 1; 489 if (keys[1].fmr_physical < keys[0].fmr_physical) 490 return 0; 491 start_fsb = keys[0].fmr_physical; 492 end_fsb = keys[1].fmr_physical; 493 494 /* Determine first and last group to examine based on start and end */ 495 ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster); 496 ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster); 497 498 /* 499 * Convert the fsmap low/high keys to bg based keys. Initialize 500 * low to the fsmap low key and max out the high key to the end 501 * of the bg. 502 */ 503 info->gfi_low = keys[0]; 504 info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster); 505 info->gfi_low.fmr_length = 0; 506 507 memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high)); 508 509 /* Assemble a list of all the fixed-location metadata. */ 510 error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list); 511 if (error) 512 goto err; 513 514 /* Query each bg */ 515 for (info->gfi_agno = start_ag; 516 info->gfi_agno <= end_ag; 517 info->gfi_agno++) { 518 /* 519 * Set the bg high key from the fsmap high key if this 520 * is the last bg that we're querying. 521 */ 522 if (info->gfi_agno == end_ag) { 523 info->gfi_high = keys[1]; 524 info->gfi_high.fmr_physical = EXT4_C2B(sbi, 525 last_cluster); 526 info->gfi_high.fmr_length = 0; 527 } 528 529 trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno, 530 info->gfi_low.fmr_physical, 531 info->gfi_low.fmr_length, 532 info->gfi_low.fmr_owner); 533 534 trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno, 535 info->gfi_high.fmr_physical, 536 info->gfi_high.fmr_length, 537 info->gfi_high.fmr_owner); 538 539 error = ext4_mballoc_query_range(sb, info->gfi_agno, 540 EXT4_B2C(sbi, info->gfi_low.fmr_physical), 541 EXT4_B2C(sbi, info->gfi_high.fmr_physical), 542 ext4_getfsmap_datadev_helper, info); 543 if (error) 544 goto err; 545 546 /* 547 * Set the bg low key to the start of the bg prior to 548 * moving on to the next bg. 549 */ 550 if (info->gfi_agno == start_ag) 551 memset(&info->gfi_low, 0, sizeof(info->gfi_low)); 552 } 553 554 /* Do we have a retained free extent? */ 555 if (info->gfi_lastfree.fmr_owner) { 556 error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree); 557 if (error) 558 goto err; 559 } 560 561 /* Report any gaps at the end of the bg */ 562 info->gfi_last = true; 563 error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info); 564 if (error) 565 goto err; 566 567 err: 568 ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list); 569 return error; 570 } 571 572 /* Do we recognize the device? */ 573 static bool ext4_getfsmap_is_valid_device(struct super_block *sb, 574 struct ext4_fsmap *fm) 575 { 576 if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX || 577 fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev)) 578 return true; 579 if (EXT4_SB(sb)->s_journal_bdev_file && 580 fm->fmr_device == 581 new_encode_dev(file_bdev(EXT4_SB(sb)->s_journal_bdev_file)->bd_dev)) 582 return true; 583 return false; 584 } 585 586 /* Ensure that the low key is less than the high key. */ 587 static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key, 588 struct ext4_fsmap *high_key) 589 { 590 if (low_key->fmr_device > high_key->fmr_device) 591 return false; 592 if (low_key->fmr_device < high_key->fmr_device) 593 return true; 594 595 if (low_key->fmr_physical > high_key->fmr_physical) 596 return false; 597 if (low_key->fmr_physical < high_key->fmr_physical) 598 return true; 599 600 if (low_key->fmr_owner > high_key->fmr_owner) 601 return false; 602 if (low_key->fmr_owner < high_key->fmr_owner) 603 return true; 604 605 return false; 606 } 607 608 #define EXT4_GETFSMAP_DEVS 2 609 /* 610 * Get filesystem's extents as described in head, and format for 611 * output. Calls formatter to fill the user's buffer until all 612 * extents are mapped, until the passed-in head->fmh_count slots have 613 * been filled, or until the formatter short-circuits the loop, if it 614 * is tracking filled-in extents on its own. 615 * 616 * Key to Confusion 617 * ---------------- 618 * There are multiple levels of keys and counters at work here: 619 * _fsmap_head.fmh_keys -- low and high fsmap keys passed in; 620 * these reflect fs-wide block addrs. 621 * dkeys -- fmh_keys used to query each device; 622 * these are fmh_keys but w/ the low key 623 * bumped up by fmr_length. 624 * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this 625 * is how we detect gaps in the fsmap 626 * records and report them. 627 * _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from 628 * dkeys; used to query the free space. 629 */ 630 int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head, 631 ext4_fsmap_format_t formatter, void *arg) 632 { 633 struct ext4_fsmap dkeys[2]; /* per-dev keys */ 634 struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS]; 635 struct ext4_getfsmap_info info = { NULL }; 636 int i; 637 int error = 0; 638 639 if (head->fmh_iflags & ~FMH_IF_VALID) 640 return -EINVAL; 641 if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) || 642 !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1])) 643 return -EINVAL; 644 645 head->fmh_entries = 0; 646 647 /* Set up our device handlers. */ 648 memset(handlers, 0, sizeof(handlers)); 649 handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev); 650 handlers[0].gfd_fn = ext4_getfsmap_datadev; 651 if (EXT4_SB(sb)->s_journal_bdev_file) { 652 handlers[1].gfd_dev = new_encode_dev( 653 file_bdev(EXT4_SB(sb)->s_journal_bdev_file)->bd_dev); 654 handlers[1].gfd_fn = ext4_getfsmap_logdev; 655 } 656 657 sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev), 658 ext4_getfsmap_dev_compare, NULL); 659 660 /* 661 * To continue where we left off, we allow userspace to use the 662 * last mapping from a previous call as the low key of the next. 663 * This is identified by a non-zero length in the low key. We 664 * have to increment the low key in this scenario to ensure we 665 * don't return the same mapping again, and instead return the 666 * very next mapping. 667 * 668 * Bump the physical offset as there can be no other mapping for 669 * the same physical block range. 670 */ 671 dkeys[0] = head->fmh_keys[0]; 672 dkeys[0].fmr_physical += dkeys[0].fmr_length; 673 dkeys[0].fmr_owner = 0; 674 dkeys[0].fmr_length = 0; 675 memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap)); 676 677 if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1])) 678 return -EINVAL; 679 680 info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical + 681 head->fmh_keys[0].fmr_length; 682 info.gfi_formatter = formatter; 683 info.gfi_format_arg = arg; 684 info.gfi_head = head; 685 686 /* For each device we support... */ 687 for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) { 688 /* Is this device within the range the user asked for? */ 689 if (!handlers[i].gfd_fn) 690 continue; 691 if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev) 692 continue; 693 if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev) 694 break; 695 696 /* 697 * If this device number matches the high key, we have 698 * to pass the high key to the handler to limit the 699 * query results. If the device number exceeds the 700 * low key, zero out the low key so that we get 701 * everything from the beginning. 702 */ 703 if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device) 704 dkeys[1] = head->fmh_keys[1]; 705 if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device) 706 memset(&dkeys[0], 0, sizeof(struct ext4_fsmap)); 707 708 info.gfi_dev = handlers[i].gfd_dev; 709 info.gfi_last = false; 710 info.gfi_agno = -1; 711 error = handlers[i].gfd_fn(sb, dkeys, &info); 712 if (error) 713 break; 714 info.gfi_next_fsblk = 0; 715 } 716 717 head->fmh_oflags = FMH_OF_DEV_T; 718 return error; 719 } 720