1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2017-2018 HUAWEI, Inc. 4 * https://www.huawei.com/ 5 * Copyright (C) 2021, Alibaba Cloud 6 */ 7 #include <linux/module.h> 8 #include <linux/buffer_head.h> 9 #include <linux/statfs.h> 10 #include <linux/parser.h> 11 #include <linux/seq_file.h> 12 #include <linux/crc32c.h> 13 #include <linux/fs_context.h> 14 #include <linux/fs_parser.h> 15 #include <linux/dax.h> 16 #include <linux/exportfs.h> 17 #include "xattr.h" 18 19 #define CREATE_TRACE_POINTS 20 #include <trace/events/erofs.h> 21 22 static struct kmem_cache *erofs_inode_cachep __read_mostly; 23 24 void _erofs_err(struct super_block *sb, const char *function, 25 const char *fmt, ...) 26 { 27 struct va_format vaf; 28 va_list args; 29 30 va_start(args, fmt); 31 32 vaf.fmt = fmt; 33 vaf.va = &args; 34 35 pr_err("(device %s): %s: %pV", sb->s_id, function, &vaf); 36 va_end(args); 37 } 38 39 void _erofs_info(struct super_block *sb, const char *function, 40 const char *fmt, ...) 41 { 42 struct va_format vaf; 43 va_list args; 44 45 va_start(args, fmt); 46 47 vaf.fmt = fmt; 48 vaf.va = &args; 49 50 pr_info("(device %s): %pV", sb->s_id, &vaf); 51 va_end(args); 52 } 53 54 static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata) 55 { 56 struct erofs_super_block *dsb; 57 u32 expected_crc, crc; 58 59 dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET, 60 EROFS_BLKSIZ - EROFS_SUPER_OFFSET, GFP_KERNEL); 61 if (!dsb) 62 return -ENOMEM; 63 64 expected_crc = le32_to_cpu(dsb->checksum); 65 dsb->checksum = 0; 66 /* to allow for x86 boot sectors and other oddities. */ 67 crc = crc32c(~0, dsb, EROFS_BLKSIZ - EROFS_SUPER_OFFSET); 68 kfree(dsb); 69 70 if (crc != expected_crc) { 71 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected", 72 crc, expected_crc); 73 return -EBADMSG; 74 } 75 return 0; 76 } 77 78 static void erofs_inode_init_once(void *ptr) 79 { 80 struct erofs_inode *vi = ptr; 81 82 inode_init_once(&vi->vfs_inode); 83 } 84 85 static struct inode *erofs_alloc_inode(struct super_block *sb) 86 { 87 struct erofs_inode *vi = 88 alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL); 89 90 if (!vi) 91 return NULL; 92 93 /* zero out everything except vfs_inode */ 94 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode)); 95 return &vi->vfs_inode; 96 } 97 98 static void erofs_free_inode(struct inode *inode) 99 { 100 struct erofs_inode *vi = EROFS_I(inode); 101 102 /* be careful of RCU symlink path */ 103 if (inode->i_op == &erofs_fast_symlink_iops) 104 kfree(inode->i_link); 105 kfree(vi->xattr_shared_xattrs); 106 107 kmem_cache_free(erofs_inode_cachep, vi); 108 } 109 110 static bool check_layout_compatibility(struct super_block *sb, 111 struct erofs_super_block *dsb) 112 { 113 const unsigned int feature = le32_to_cpu(dsb->feature_incompat); 114 115 EROFS_SB(sb)->feature_incompat = feature; 116 117 /* check if current kernel meets all mandatory requirements */ 118 if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) { 119 erofs_err(sb, 120 "unidentified incompatible feature %x, please upgrade kernel version", 121 feature & ~EROFS_ALL_FEATURE_INCOMPAT); 122 return false; 123 } 124 return true; 125 } 126 127 #ifdef CONFIG_EROFS_FS_ZIP 128 /* read variable-sized metadata, offset will be aligned by 4-byte */ 129 static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf, 130 erofs_off_t *offset, int *lengthp) 131 { 132 u8 *buffer, *ptr; 133 int len, i, cnt; 134 135 *offset = round_up(*offset, 4); 136 ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), EROFS_KMAP); 137 if (IS_ERR(ptr)) 138 return ptr; 139 140 len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]); 141 if (!len) 142 len = U16_MAX + 1; 143 buffer = kmalloc(len, GFP_KERNEL); 144 if (!buffer) 145 return ERR_PTR(-ENOMEM); 146 *offset += sizeof(__le16); 147 *lengthp = len; 148 149 for (i = 0; i < len; i += cnt) { 150 cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i); 151 ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), 152 EROFS_KMAP); 153 if (IS_ERR(ptr)) { 154 kfree(buffer); 155 return ptr; 156 } 157 memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt); 158 *offset += cnt; 159 } 160 return buffer; 161 } 162 163 static int erofs_load_compr_cfgs(struct super_block *sb, 164 struct erofs_super_block *dsb) 165 { 166 struct erofs_sb_info *sbi = EROFS_SB(sb); 167 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 168 unsigned int algs, alg; 169 erofs_off_t offset; 170 int size, ret = 0; 171 172 sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs); 173 if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) { 174 erofs_err(sb, "try to load compressed fs with unsupported algorithms %x", 175 sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS); 176 return -EINVAL; 177 } 178 179 offset = EROFS_SUPER_OFFSET + sbi->sb_size; 180 alg = 0; 181 for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) { 182 void *data; 183 184 if (!(algs & 1)) 185 continue; 186 187 data = erofs_read_metadata(sb, &buf, &offset, &size); 188 if (IS_ERR(data)) { 189 ret = PTR_ERR(data); 190 break; 191 } 192 193 switch (alg) { 194 case Z_EROFS_COMPRESSION_LZ4: 195 ret = z_erofs_load_lz4_config(sb, dsb, data, size); 196 break; 197 case Z_EROFS_COMPRESSION_LZMA: 198 ret = z_erofs_load_lzma_config(sb, dsb, data, size); 199 break; 200 default: 201 DBG_BUGON(1); 202 ret = -EFAULT; 203 } 204 kfree(data); 205 if (ret) 206 break; 207 } 208 erofs_put_metabuf(&buf); 209 return ret; 210 } 211 #else 212 static int erofs_load_compr_cfgs(struct super_block *sb, 213 struct erofs_super_block *dsb) 214 { 215 if (dsb->u1.available_compr_algs) { 216 erofs_err(sb, "try to load compressed fs when compression is disabled"); 217 return -EINVAL; 218 } 219 return 0; 220 } 221 #endif 222 223 static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb, 224 struct erofs_device_info *dif, erofs_off_t *pos) 225 { 226 struct erofs_sb_info *sbi = EROFS_SB(sb); 227 struct erofs_deviceslot *dis; 228 struct block_device *bdev; 229 void *ptr; 230 int ret; 231 232 ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*pos), EROFS_KMAP); 233 if (IS_ERR(ptr)) 234 return PTR_ERR(ptr); 235 dis = ptr + erofs_blkoff(*pos); 236 237 if (!dif->path) { 238 if (!dis->tag[0]) { 239 erofs_err(sb, "empty device tag @ pos %llu", *pos); 240 return -EINVAL; 241 } 242 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL); 243 if (!dif->path) 244 return -ENOMEM; 245 } 246 247 if (erofs_is_fscache_mode(sb)) { 248 ret = erofs_fscache_register_cookie(sb, &dif->fscache, 249 dif->path, false); 250 if (ret) 251 return ret; 252 } else { 253 bdev = blkdev_get_by_path(dif->path, FMODE_READ | FMODE_EXCL, 254 sb->s_type); 255 if (IS_ERR(bdev)) 256 return PTR_ERR(bdev); 257 dif->bdev = bdev; 258 dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off, 259 NULL, NULL); 260 } 261 262 dif->blocks = le32_to_cpu(dis->blocks); 263 dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr); 264 sbi->total_blocks += dif->blocks; 265 *pos += EROFS_DEVT_SLOT_SIZE; 266 return 0; 267 } 268 269 static int erofs_scan_devices(struct super_block *sb, 270 struct erofs_super_block *dsb) 271 { 272 struct erofs_sb_info *sbi = EROFS_SB(sb); 273 unsigned int ondisk_extradevs; 274 erofs_off_t pos; 275 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 276 struct erofs_device_info *dif; 277 int id, err = 0; 278 279 sbi->total_blocks = sbi->primarydevice_blocks; 280 if (!erofs_sb_has_device_table(sbi)) 281 ondisk_extradevs = 0; 282 else 283 ondisk_extradevs = le16_to_cpu(dsb->extra_devices); 284 285 if (sbi->devs->extra_devices && 286 ondisk_extradevs != sbi->devs->extra_devices) { 287 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)", 288 ondisk_extradevs, sbi->devs->extra_devices); 289 return -EINVAL; 290 } 291 if (!ondisk_extradevs) 292 return 0; 293 294 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1; 295 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE; 296 down_read(&sbi->devs->rwsem); 297 if (sbi->devs->extra_devices) { 298 idr_for_each_entry(&sbi->devs->tree, dif, id) { 299 err = erofs_init_device(&buf, sb, dif, &pos); 300 if (err) 301 break; 302 } 303 } else { 304 for (id = 0; id < ondisk_extradevs; id++) { 305 dif = kzalloc(sizeof(*dif), GFP_KERNEL); 306 if (!dif) { 307 err = -ENOMEM; 308 break; 309 } 310 311 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL); 312 if (err < 0) { 313 kfree(dif); 314 break; 315 } 316 ++sbi->devs->extra_devices; 317 318 err = erofs_init_device(&buf, sb, dif, &pos); 319 if (err) 320 break; 321 } 322 } 323 up_read(&sbi->devs->rwsem); 324 erofs_put_metabuf(&buf); 325 return err; 326 } 327 328 static int erofs_read_superblock(struct super_block *sb) 329 { 330 struct erofs_sb_info *sbi; 331 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 332 struct erofs_super_block *dsb; 333 unsigned int blkszbits; 334 void *data; 335 int ret; 336 337 data = erofs_read_metabuf(&buf, sb, 0, EROFS_KMAP); 338 if (IS_ERR(data)) { 339 erofs_err(sb, "cannot read erofs superblock"); 340 return PTR_ERR(data); 341 } 342 343 sbi = EROFS_SB(sb); 344 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET); 345 346 ret = -EINVAL; 347 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) { 348 erofs_err(sb, "cannot find valid erofs superblock"); 349 goto out; 350 } 351 352 sbi->feature_compat = le32_to_cpu(dsb->feature_compat); 353 if (erofs_sb_has_sb_chksum(sbi)) { 354 ret = erofs_superblock_csum_verify(sb, data); 355 if (ret) 356 goto out; 357 } 358 359 ret = -EINVAL; 360 blkszbits = dsb->blkszbits; 361 /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */ 362 if (blkszbits != LOG_BLOCK_SIZE) { 363 erofs_err(sb, "blkszbits %u isn't supported on this platform", 364 blkszbits); 365 goto out; 366 } 367 368 if (!check_layout_compatibility(sb, dsb)) 369 goto out; 370 371 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE; 372 if (sbi->sb_size > EROFS_BLKSIZ) { 373 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)", 374 sbi->sb_size); 375 goto out; 376 } 377 sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks); 378 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr); 379 #ifdef CONFIG_EROFS_FS_XATTR 380 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr); 381 #endif 382 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact)); 383 sbi->root_nid = le16_to_cpu(dsb->root_nid); 384 sbi->inos = le64_to_cpu(dsb->inos); 385 386 sbi->build_time = le64_to_cpu(dsb->build_time); 387 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec); 388 389 memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid)); 390 391 ret = strscpy(sbi->volume_name, dsb->volume_name, 392 sizeof(dsb->volume_name)); 393 if (ret < 0) { /* -E2BIG */ 394 erofs_err(sb, "bad volume name without NIL terminator"); 395 ret = -EFSCORRUPTED; 396 goto out; 397 } 398 399 /* parse on-disk compression configurations */ 400 if (erofs_sb_has_compr_cfgs(sbi)) 401 ret = erofs_load_compr_cfgs(sb, dsb); 402 else 403 ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0); 404 if (ret < 0) 405 goto out; 406 407 /* handle multiple devices */ 408 ret = erofs_scan_devices(sb, dsb); 409 410 if (erofs_sb_has_ztailpacking(sbi)) 411 erofs_info(sb, "EXPERIMENTAL compressed inline data feature in use. Use at your own risk!"); 412 if (erofs_is_fscache_mode(sb)) 413 erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!"); 414 out: 415 erofs_put_metabuf(&buf); 416 return ret; 417 } 418 419 /* set up default EROFS parameters */ 420 static void erofs_default_options(struct erofs_fs_context *ctx) 421 { 422 #ifdef CONFIG_EROFS_FS_ZIP 423 ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND; 424 ctx->opt.max_sync_decompress_pages = 3; 425 ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO; 426 #endif 427 #ifdef CONFIG_EROFS_FS_XATTR 428 set_opt(&ctx->opt, XATTR_USER); 429 #endif 430 #ifdef CONFIG_EROFS_FS_POSIX_ACL 431 set_opt(&ctx->opt, POSIX_ACL); 432 #endif 433 } 434 435 enum { 436 Opt_user_xattr, 437 Opt_acl, 438 Opt_cache_strategy, 439 Opt_dax, 440 Opt_dax_enum, 441 Opt_device, 442 Opt_fsid, 443 Opt_err 444 }; 445 446 static const struct constant_table erofs_param_cache_strategy[] = { 447 {"disabled", EROFS_ZIP_CACHE_DISABLED}, 448 {"readahead", EROFS_ZIP_CACHE_READAHEAD}, 449 {"readaround", EROFS_ZIP_CACHE_READAROUND}, 450 {} 451 }; 452 453 static const struct constant_table erofs_dax_param_enums[] = { 454 {"always", EROFS_MOUNT_DAX_ALWAYS}, 455 {"never", EROFS_MOUNT_DAX_NEVER}, 456 {} 457 }; 458 459 static const struct fs_parameter_spec erofs_fs_parameters[] = { 460 fsparam_flag_no("user_xattr", Opt_user_xattr), 461 fsparam_flag_no("acl", Opt_acl), 462 fsparam_enum("cache_strategy", Opt_cache_strategy, 463 erofs_param_cache_strategy), 464 fsparam_flag("dax", Opt_dax), 465 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums), 466 fsparam_string("device", Opt_device), 467 fsparam_string("fsid", Opt_fsid), 468 {} 469 }; 470 471 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode) 472 { 473 #ifdef CONFIG_FS_DAX 474 struct erofs_fs_context *ctx = fc->fs_private; 475 476 switch (mode) { 477 case EROFS_MOUNT_DAX_ALWAYS: 478 warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); 479 set_opt(&ctx->opt, DAX_ALWAYS); 480 clear_opt(&ctx->opt, DAX_NEVER); 481 return true; 482 case EROFS_MOUNT_DAX_NEVER: 483 set_opt(&ctx->opt, DAX_NEVER); 484 clear_opt(&ctx->opt, DAX_ALWAYS); 485 return true; 486 default: 487 DBG_BUGON(1); 488 return false; 489 } 490 #else 491 errorfc(fc, "dax options not supported"); 492 return false; 493 #endif 494 } 495 496 static int erofs_fc_parse_param(struct fs_context *fc, 497 struct fs_parameter *param) 498 { 499 struct erofs_fs_context *ctx = fc->fs_private; 500 struct fs_parse_result result; 501 struct erofs_device_info *dif; 502 int opt, ret; 503 504 opt = fs_parse(fc, erofs_fs_parameters, param, &result); 505 if (opt < 0) 506 return opt; 507 508 switch (opt) { 509 case Opt_user_xattr: 510 #ifdef CONFIG_EROFS_FS_XATTR 511 if (result.boolean) 512 set_opt(&ctx->opt, XATTR_USER); 513 else 514 clear_opt(&ctx->opt, XATTR_USER); 515 #else 516 errorfc(fc, "{,no}user_xattr options not supported"); 517 #endif 518 break; 519 case Opt_acl: 520 #ifdef CONFIG_EROFS_FS_POSIX_ACL 521 if (result.boolean) 522 set_opt(&ctx->opt, POSIX_ACL); 523 else 524 clear_opt(&ctx->opt, POSIX_ACL); 525 #else 526 errorfc(fc, "{,no}acl options not supported"); 527 #endif 528 break; 529 case Opt_cache_strategy: 530 #ifdef CONFIG_EROFS_FS_ZIP 531 ctx->opt.cache_strategy = result.uint_32; 532 #else 533 errorfc(fc, "compression not supported, cache_strategy ignored"); 534 #endif 535 break; 536 case Opt_dax: 537 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS)) 538 return -EINVAL; 539 break; 540 case Opt_dax_enum: 541 if (!erofs_fc_set_dax_mode(fc, result.uint_32)) 542 return -EINVAL; 543 break; 544 case Opt_device: 545 dif = kzalloc(sizeof(*dif), GFP_KERNEL); 546 if (!dif) 547 return -ENOMEM; 548 dif->path = kstrdup(param->string, GFP_KERNEL); 549 if (!dif->path) { 550 kfree(dif); 551 return -ENOMEM; 552 } 553 down_write(&ctx->devs->rwsem); 554 ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL); 555 up_write(&ctx->devs->rwsem); 556 if (ret < 0) { 557 kfree(dif->path); 558 kfree(dif); 559 return ret; 560 } 561 ++ctx->devs->extra_devices; 562 break; 563 case Opt_fsid: 564 #ifdef CONFIG_EROFS_FS_ONDEMAND 565 kfree(ctx->opt.fsid); 566 ctx->opt.fsid = kstrdup(param->string, GFP_KERNEL); 567 if (!ctx->opt.fsid) 568 return -ENOMEM; 569 #else 570 errorfc(fc, "fsid option not supported"); 571 #endif 572 break; 573 default: 574 return -ENOPARAM; 575 } 576 return 0; 577 } 578 579 #ifdef CONFIG_EROFS_FS_ZIP 580 static const struct address_space_operations managed_cache_aops; 581 582 static bool erofs_managed_cache_release_folio(struct folio *folio, gfp_t gfp) 583 { 584 bool ret = true; 585 struct address_space *const mapping = folio->mapping; 586 587 DBG_BUGON(!folio_test_locked(folio)); 588 DBG_BUGON(mapping->a_ops != &managed_cache_aops); 589 590 if (folio_test_private(folio)) 591 ret = erofs_try_to_free_cached_page(&folio->page); 592 593 return ret; 594 } 595 596 /* 597 * It will be called only on inode eviction. In case that there are still some 598 * decompression requests in progress, wait with rescheduling for a bit here. 599 * We could introduce an extra locking instead but it seems unnecessary. 600 */ 601 static void erofs_managed_cache_invalidate_folio(struct folio *folio, 602 size_t offset, size_t length) 603 { 604 const size_t stop = length + offset; 605 606 DBG_BUGON(!folio_test_locked(folio)); 607 608 /* Check for potential overflow in debug mode */ 609 DBG_BUGON(stop > folio_size(folio) || stop < length); 610 611 if (offset == 0 && stop == folio_size(folio)) 612 while (!erofs_managed_cache_release_folio(folio, GFP_NOFS)) 613 cond_resched(); 614 } 615 616 static const struct address_space_operations managed_cache_aops = { 617 .release_folio = erofs_managed_cache_release_folio, 618 .invalidate_folio = erofs_managed_cache_invalidate_folio, 619 }; 620 621 static int erofs_init_managed_cache(struct super_block *sb) 622 { 623 struct erofs_sb_info *const sbi = EROFS_SB(sb); 624 struct inode *const inode = new_inode(sb); 625 626 if (!inode) 627 return -ENOMEM; 628 629 set_nlink(inode, 1); 630 inode->i_size = OFFSET_MAX; 631 632 inode->i_mapping->a_ops = &managed_cache_aops; 633 mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); 634 sbi->managed_cache = inode; 635 return 0; 636 } 637 #else 638 static int erofs_init_managed_cache(struct super_block *sb) { return 0; } 639 #endif 640 641 static struct inode *erofs_nfs_get_inode(struct super_block *sb, 642 u64 ino, u32 generation) 643 { 644 return erofs_iget(sb, ino, false); 645 } 646 647 static struct dentry *erofs_fh_to_dentry(struct super_block *sb, 648 struct fid *fid, int fh_len, int fh_type) 649 { 650 return generic_fh_to_dentry(sb, fid, fh_len, fh_type, 651 erofs_nfs_get_inode); 652 } 653 654 static struct dentry *erofs_fh_to_parent(struct super_block *sb, 655 struct fid *fid, int fh_len, int fh_type) 656 { 657 return generic_fh_to_parent(sb, fid, fh_len, fh_type, 658 erofs_nfs_get_inode); 659 } 660 661 static struct dentry *erofs_get_parent(struct dentry *child) 662 { 663 erofs_nid_t nid; 664 unsigned int d_type; 665 int err; 666 667 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type); 668 if (err) 669 return ERR_PTR(err); 670 return d_obtain_alias(erofs_iget(child->d_sb, nid, d_type == FT_DIR)); 671 } 672 673 static const struct export_operations erofs_export_ops = { 674 .fh_to_dentry = erofs_fh_to_dentry, 675 .fh_to_parent = erofs_fh_to_parent, 676 .get_parent = erofs_get_parent, 677 }; 678 679 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) 680 { 681 struct inode *inode; 682 struct erofs_sb_info *sbi; 683 struct erofs_fs_context *ctx = fc->fs_private; 684 int err; 685 686 sb->s_magic = EROFS_SUPER_MAGIC; 687 sb->s_flags |= SB_RDONLY | SB_NOATIME; 688 sb->s_maxbytes = MAX_LFS_FILESIZE; 689 sb->s_op = &erofs_sops; 690 691 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); 692 if (!sbi) 693 return -ENOMEM; 694 695 sb->s_fs_info = sbi; 696 sbi->opt = ctx->opt; 697 ctx->opt.fsid = NULL; 698 sbi->devs = ctx->devs; 699 ctx->devs = NULL; 700 701 if (erofs_is_fscache_mode(sb)) { 702 sb->s_blocksize = EROFS_BLKSIZ; 703 sb->s_blocksize_bits = LOG_BLOCK_SIZE; 704 705 err = erofs_fscache_register_fs(sb); 706 if (err) 707 return err; 708 709 err = erofs_fscache_register_cookie(sb, &sbi->s_fscache, 710 sbi->opt.fsid, true); 711 if (err) 712 return err; 713 714 err = super_setup_bdi(sb); 715 if (err) 716 return err; 717 } else { 718 if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) { 719 erofs_err(sb, "failed to set erofs blksize"); 720 return -EINVAL; 721 } 722 723 sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev, 724 &sbi->dax_part_off, 725 NULL, NULL); 726 } 727 728 err = erofs_read_superblock(sb); 729 if (err) 730 return err; 731 732 if (test_opt(&sbi->opt, DAX_ALWAYS)) { 733 BUILD_BUG_ON(EROFS_BLKSIZ != PAGE_SIZE); 734 735 if (!sbi->dax_dev) { 736 errorfc(fc, "DAX unsupported by block device. Turning off DAX."); 737 clear_opt(&sbi->opt, DAX_ALWAYS); 738 } 739 } 740 741 sb->s_time_gran = 1; 742 sb->s_xattr = erofs_xattr_handlers; 743 sb->s_export_op = &erofs_export_ops; 744 745 if (test_opt(&sbi->opt, POSIX_ACL)) 746 sb->s_flags |= SB_POSIXACL; 747 else 748 sb->s_flags &= ~SB_POSIXACL; 749 750 #ifdef CONFIG_EROFS_FS_ZIP 751 xa_init(&sbi->managed_pslots); 752 #endif 753 754 /* get the root inode */ 755 inode = erofs_iget(sb, ROOT_NID(sbi), true); 756 if (IS_ERR(inode)) 757 return PTR_ERR(inode); 758 759 if (!S_ISDIR(inode->i_mode)) { 760 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)", 761 ROOT_NID(sbi), inode->i_mode); 762 iput(inode); 763 return -EINVAL; 764 } 765 766 sb->s_root = d_make_root(inode); 767 if (!sb->s_root) 768 return -ENOMEM; 769 770 erofs_shrinker_register(sb); 771 /* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */ 772 err = erofs_init_managed_cache(sb); 773 if (err) 774 return err; 775 776 err = erofs_register_sysfs(sb); 777 if (err) 778 return err; 779 780 erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi)); 781 return 0; 782 } 783 784 static int erofs_fc_get_tree(struct fs_context *fc) 785 { 786 struct erofs_fs_context *ctx = fc->fs_private; 787 788 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->opt.fsid) 789 return get_tree_nodev(fc, erofs_fc_fill_super); 790 791 return get_tree_bdev(fc, erofs_fc_fill_super); 792 } 793 794 static int erofs_fc_reconfigure(struct fs_context *fc) 795 { 796 struct super_block *sb = fc->root->d_sb; 797 struct erofs_sb_info *sbi = EROFS_SB(sb); 798 struct erofs_fs_context *ctx = fc->fs_private; 799 800 DBG_BUGON(!sb_rdonly(sb)); 801 802 if (test_opt(&ctx->opt, POSIX_ACL)) 803 fc->sb_flags |= SB_POSIXACL; 804 else 805 fc->sb_flags &= ~SB_POSIXACL; 806 807 sbi->opt = ctx->opt; 808 809 fc->sb_flags |= SB_RDONLY; 810 return 0; 811 } 812 813 static int erofs_release_device_info(int id, void *ptr, void *data) 814 { 815 struct erofs_device_info *dif = ptr; 816 817 fs_put_dax(dif->dax_dev, NULL); 818 if (dif->bdev) 819 blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL); 820 erofs_fscache_unregister_cookie(&dif->fscache); 821 kfree(dif->path); 822 kfree(dif); 823 return 0; 824 } 825 826 static void erofs_free_dev_context(struct erofs_dev_context *devs) 827 { 828 if (!devs) 829 return; 830 idr_for_each(&devs->tree, &erofs_release_device_info, NULL); 831 idr_destroy(&devs->tree); 832 kfree(devs); 833 } 834 835 static void erofs_fc_free(struct fs_context *fc) 836 { 837 struct erofs_fs_context *ctx = fc->fs_private; 838 839 erofs_free_dev_context(ctx->devs); 840 kfree(ctx->opt.fsid); 841 kfree(ctx); 842 } 843 844 static const struct fs_context_operations erofs_context_ops = { 845 .parse_param = erofs_fc_parse_param, 846 .get_tree = erofs_fc_get_tree, 847 .reconfigure = erofs_fc_reconfigure, 848 .free = erofs_fc_free, 849 }; 850 851 static int erofs_init_fs_context(struct fs_context *fc) 852 { 853 struct erofs_fs_context *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); 854 855 if (!ctx) 856 return -ENOMEM; 857 ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL); 858 if (!ctx->devs) { 859 kfree(ctx); 860 return -ENOMEM; 861 } 862 fc->fs_private = ctx; 863 864 idr_init(&ctx->devs->tree); 865 init_rwsem(&ctx->devs->rwsem); 866 erofs_default_options(ctx); 867 fc->ops = &erofs_context_ops; 868 return 0; 869 } 870 871 /* 872 * could be triggered after deactivate_locked_super() 873 * is called, thus including umount and failed to initialize. 874 */ 875 static void erofs_kill_sb(struct super_block *sb) 876 { 877 struct erofs_sb_info *sbi; 878 879 WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC); 880 881 if (erofs_is_fscache_mode(sb)) 882 generic_shutdown_super(sb); 883 else 884 kill_block_super(sb); 885 886 sbi = EROFS_SB(sb); 887 if (!sbi) 888 return; 889 890 erofs_free_dev_context(sbi->devs); 891 fs_put_dax(sbi->dax_dev, NULL); 892 erofs_fscache_unregister_cookie(&sbi->s_fscache); 893 erofs_fscache_unregister_fs(sb); 894 kfree(sbi->opt.fsid); 895 kfree(sbi); 896 sb->s_fs_info = NULL; 897 } 898 899 /* called when ->s_root is non-NULL */ 900 static void erofs_put_super(struct super_block *sb) 901 { 902 struct erofs_sb_info *const sbi = EROFS_SB(sb); 903 904 DBG_BUGON(!sbi); 905 906 erofs_unregister_sysfs(sb); 907 erofs_shrinker_unregister(sb); 908 #ifdef CONFIG_EROFS_FS_ZIP 909 iput(sbi->managed_cache); 910 sbi->managed_cache = NULL; 911 #endif 912 erofs_fscache_unregister_cookie(&sbi->s_fscache); 913 } 914 915 static struct file_system_type erofs_fs_type = { 916 .owner = THIS_MODULE, 917 .name = "erofs", 918 .init_fs_context = erofs_init_fs_context, 919 .kill_sb = erofs_kill_sb, 920 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, 921 }; 922 MODULE_ALIAS_FS("erofs"); 923 924 static int __init erofs_module_init(void) 925 { 926 int err; 927 928 erofs_check_ondisk_layout_definitions(); 929 930 erofs_inode_cachep = kmem_cache_create("erofs_inode", 931 sizeof(struct erofs_inode), 0, 932 SLAB_RECLAIM_ACCOUNT, 933 erofs_inode_init_once); 934 if (!erofs_inode_cachep) { 935 err = -ENOMEM; 936 goto icache_err; 937 } 938 939 err = erofs_init_shrinker(); 940 if (err) 941 goto shrinker_err; 942 943 err = z_erofs_lzma_init(); 944 if (err) 945 goto lzma_err; 946 947 erofs_pcpubuf_init(); 948 err = z_erofs_init_zip_subsystem(); 949 if (err) 950 goto zip_err; 951 952 err = erofs_init_sysfs(); 953 if (err) 954 goto sysfs_err; 955 956 err = register_filesystem(&erofs_fs_type); 957 if (err) 958 goto fs_err; 959 960 return 0; 961 962 fs_err: 963 erofs_exit_sysfs(); 964 sysfs_err: 965 z_erofs_exit_zip_subsystem(); 966 zip_err: 967 z_erofs_lzma_exit(); 968 lzma_err: 969 erofs_exit_shrinker(); 970 shrinker_err: 971 kmem_cache_destroy(erofs_inode_cachep); 972 icache_err: 973 return err; 974 } 975 976 static void __exit erofs_module_exit(void) 977 { 978 unregister_filesystem(&erofs_fs_type); 979 980 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */ 981 rcu_barrier(); 982 983 erofs_exit_sysfs(); 984 z_erofs_exit_zip_subsystem(); 985 z_erofs_lzma_exit(); 986 erofs_exit_shrinker(); 987 kmem_cache_destroy(erofs_inode_cachep); 988 erofs_pcpubuf_exit(); 989 } 990 991 /* get filesystem statistics */ 992 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf) 993 { 994 struct super_block *sb = dentry->d_sb; 995 struct erofs_sb_info *sbi = EROFS_SB(sb); 996 u64 id = 0; 997 998 if (!erofs_is_fscache_mode(sb)) 999 id = huge_encode_dev(sb->s_bdev->bd_dev); 1000 1001 buf->f_type = sb->s_magic; 1002 buf->f_bsize = EROFS_BLKSIZ; 1003 buf->f_blocks = sbi->total_blocks; 1004 buf->f_bfree = buf->f_bavail = 0; 1005 1006 buf->f_files = ULLONG_MAX; 1007 buf->f_ffree = ULLONG_MAX - sbi->inos; 1008 1009 buf->f_namelen = EROFS_NAME_LEN; 1010 1011 buf->f_fsid = u64_to_fsid(id); 1012 return 0; 1013 } 1014 1015 static int erofs_show_options(struct seq_file *seq, struct dentry *root) 1016 { 1017 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb); 1018 struct erofs_mount_opts *opt = &sbi->opt; 1019 1020 #ifdef CONFIG_EROFS_FS_XATTR 1021 if (test_opt(opt, XATTR_USER)) 1022 seq_puts(seq, ",user_xattr"); 1023 else 1024 seq_puts(seq, ",nouser_xattr"); 1025 #endif 1026 #ifdef CONFIG_EROFS_FS_POSIX_ACL 1027 if (test_opt(opt, POSIX_ACL)) 1028 seq_puts(seq, ",acl"); 1029 else 1030 seq_puts(seq, ",noacl"); 1031 #endif 1032 #ifdef CONFIG_EROFS_FS_ZIP 1033 if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED) 1034 seq_puts(seq, ",cache_strategy=disabled"); 1035 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD) 1036 seq_puts(seq, ",cache_strategy=readahead"); 1037 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAROUND) 1038 seq_puts(seq, ",cache_strategy=readaround"); 1039 #endif 1040 if (test_opt(opt, DAX_ALWAYS)) 1041 seq_puts(seq, ",dax=always"); 1042 if (test_opt(opt, DAX_NEVER)) 1043 seq_puts(seq, ",dax=never"); 1044 #ifdef CONFIG_EROFS_FS_ONDEMAND 1045 if (opt->fsid) 1046 seq_printf(seq, ",fsid=%s", opt->fsid); 1047 #endif 1048 return 0; 1049 } 1050 1051 const struct super_operations erofs_sops = { 1052 .put_super = erofs_put_super, 1053 .alloc_inode = erofs_alloc_inode, 1054 .free_inode = erofs_free_inode, 1055 .statfs = erofs_statfs, 1056 .show_options = erofs_show_options, 1057 }; 1058 1059 module_init(erofs_module_init); 1060 module_exit(erofs_module_exit); 1061 1062 MODULE_DESCRIPTION("Enhanced ROM File System"); 1063 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc."); 1064 MODULE_LICENSE("GPL"); 1065