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/statfs.h> 8 #include <linux/seq_file.h> 9 #include <linux/crc32c.h> 10 #include <linux/fs_context.h> 11 #include <linux/fs_parser.h> 12 #include <linux/exportfs.h> 13 #include <linux/backing-dev.h> 14 #include "xattr.h" 15 16 #define CREATE_TRACE_POINTS 17 #include <trace/events/erofs.h> 18 19 static struct kmem_cache *erofs_inode_cachep __read_mostly; 20 21 void _erofs_printk(struct super_block *sb, const char *fmt, ...) 22 { 23 struct va_format vaf; 24 va_list args; 25 int level; 26 27 va_start(args, fmt); 28 29 level = printk_get_level(fmt); 30 vaf.fmt = printk_skip_level(fmt); 31 vaf.va = &args; 32 if (sb) 33 printk("%c%cerofs (device %s): %pV", 34 KERN_SOH_ASCII, level, sb->s_id, &vaf); 35 else 36 printk("%c%cerofs: %pV", KERN_SOH_ASCII, level, &vaf); 37 va_end(args); 38 } 39 40 static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata) 41 { 42 struct erofs_super_block *dsb = sbdata + EROFS_SUPER_OFFSET; 43 u32 len = 1 << EROFS_SB(sb)->blkszbits, crc; 44 45 if (len > EROFS_SUPER_OFFSET) 46 len -= EROFS_SUPER_OFFSET; 47 len -= offsetof(struct erofs_super_block, checksum) + 48 sizeof(dsb->checksum); 49 50 /* skip .magic(pre-verified) and .checksum(0) fields */ 51 crc = crc32c(0x5045B54A, (&dsb->checksum) + 1, len); 52 if (crc == le32_to_cpu(dsb->checksum)) 53 return 0; 54 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected", 55 crc, le32_to_cpu(dsb->checksum)); 56 return -EBADMSG; 57 } 58 59 static void erofs_inode_init_once(void *ptr) 60 { 61 struct erofs_inode *vi = ptr; 62 63 inode_init_once(&vi->vfs_inode); 64 } 65 66 static struct inode *erofs_alloc_inode(struct super_block *sb) 67 { 68 struct erofs_inode *vi = 69 alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL); 70 71 if (!vi) 72 return NULL; 73 74 /* zero out everything except vfs_inode */ 75 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode)); 76 return &vi->vfs_inode; 77 } 78 79 static void erofs_free_inode(struct inode *inode) 80 { 81 struct erofs_inode *vi = EROFS_I(inode); 82 83 if (inode->i_op == &erofs_fast_symlink_iops) 84 kfree(inode->i_link); 85 kfree(vi->xattr_shared_xattrs); 86 kmem_cache_free(erofs_inode_cachep, vi); 87 } 88 89 /* read variable-sized metadata, offset will be aligned by 4-byte */ 90 void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf, 91 erofs_off_t *offset, int *lengthp) 92 { 93 u8 *buffer, *ptr; 94 int len, i, cnt; 95 96 *offset = round_up(*offset, 4); 97 ptr = erofs_bread(buf, *offset, true); 98 if (IS_ERR(ptr)) 99 return ptr; 100 101 len = le16_to_cpu(*(__le16 *)ptr); 102 if (!len) 103 len = U16_MAX + 1; 104 buffer = kmalloc(len, GFP_KERNEL); 105 if (!buffer) 106 return ERR_PTR(-ENOMEM); 107 *offset += sizeof(__le16); 108 *lengthp = len; 109 110 for (i = 0; i < len; i += cnt) { 111 cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset), 112 len - i); 113 ptr = erofs_bread(buf, *offset, true); 114 if (IS_ERR(ptr)) { 115 kfree(buffer); 116 return ptr; 117 } 118 memcpy(buffer + i, ptr, cnt); 119 *offset += cnt; 120 } 121 return buffer; 122 } 123 124 #ifndef CONFIG_EROFS_FS_ZIP 125 static int z_erofs_parse_cfgs(struct super_block *sb, 126 struct erofs_super_block *dsb) 127 { 128 if (!dsb->u1.available_compr_algs) 129 return 0; 130 131 erofs_err(sb, "compression disabled, unable to mount compressed EROFS"); 132 return -EOPNOTSUPP; 133 } 134 #endif 135 136 static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb, 137 struct erofs_device_info *dif, erofs_off_t *pos) 138 { 139 struct erofs_sb_info *sbi = EROFS_SB(sb); 140 struct erofs_fscache *fscache; 141 struct erofs_deviceslot *dis; 142 struct file *file; 143 144 dis = erofs_read_metabuf(buf, sb, *pos, false); 145 if (IS_ERR(dis)) 146 return PTR_ERR(dis); 147 148 if (!sbi->devs->flatdev && !dif->path) { 149 if (!dis->tag[0]) { 150 erofs_err(sb, "empty device tag @ pos %llu", *pos); 151 return -EINVAL; 152 } 153 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL); 154 if (!dif->path) 155 return -ENOMEM; 156 } 157 158 if (erofs_is_fscache_mode(sb)) { 159 fscache = erofs_fscache_register_cookie(sb, dif->path, 0); 160 if (IS_ERR(fscache)) 161 return PTR_ERR(fscache); 162 dif->fscache = fscache; 163 } else if (!sbi->devs->flatdev) { 164 file = erofs_is_fileio_mode(sbi) ? 165 filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) : 166 bdev_file_open_by_path(dif->path, 167 BLK_OPEN_READ, sb->s_type, NULL); 168 if (IS_ERR(file)) { 169 if (file == ERR_PTR(-ENOTBLK)) 170 return -EINVAL; 171 return PTR_ERR(file); 172 } 173 174 if (!erofs_is_fileio_mode(sbi)) { 175 dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file), 176 &dif->dax_part_off, NULL, NULL); 177 if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) { 178 erofs_info(sb, "DAX unsupported by %s. Turning off DAX.", 179 dif->path); 180 clear_opt(&sbi->opt, DAX_ALWAYS); 181 } 182 } else if (!S_ISREG(file_inode(file)->i_mode)) { 183 fput(file); 184 return -EINVAL; 185 } 186 dif->file = file; 187 } 188 189 dif->blocks = le32_to_cpu(dis->blocks_lo); 190 dif->uniaddr = le32_to_cpu(dis->uniaddr_lo); 191 sbi->total_blocks += dif->blocks; 192 *pos += EROFS_DEVT_SLOT_SIZE; 193 return 0; 194 } 195 196 static int erofs_scan_devices(struct super_block *sb, 197 struct erofs_super_block *dsb) 198 { 199 struct erofs_sb_info *sbi = EROFS_SB(sb); 200 unsigned int ondisk_extradevs; 201 erofs_off_t pos; 202 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 203 struct erofs_device_info *dif; 204 int id, err = 0; 205 206 sbi->total_blocks = sbi->dif0.blocks; 207 if (!erofs_sb_has_device_table(sbi)) 208 ondisk_extradevs = 0; 209 else 210 ondisk_extradevs = le16_to_cpu(dsb->extra_devices); 211 212 if (sbi->devs->extra_devices && 213 ondisk_extradevs != sbi->devs->extra_devices) { 214 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)", 215 ondisk_extradevs, sbi->devs->extra_devices); 216 return -EINVAL; 217 } 218 if (!ondisk_extradevs) { 219 if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) { 220 erofs_info(sb, "DAX unsupported by block device. Turning off DAX."); 221 clear_opt(&sbi->opt, DAX_ALWAYS); 222 } 223 return 0; 224 } 225 226 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb)) 227 sbi->devs->flatdev = true; 228 229 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1; 230 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE; 231 down_read(&sbi->devs->rwsem); 232 if (sbi->devs->extra_devices) { 233 idr_for_each_entry(&sbi->devs->tree, dif, id) { 234 err = erofs_init_device(&buf, sb, dif, &pos); 235 if (err) 236 break; 237 } 238 } else { 239 for (id = 0; id < ondisk_extradevs; id++) { 240 dif = kzalloc(sizeof(*dif), GFP_KERNEL); 241 if (!dif) { 242 err = -ENOMEM; 243 break; 244 } 245 246 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL); 247 if (err < 0) { 248 kfree(dif); 249 break; 250 } 251 ++sbi->devs->extra_devices; 252 253 err = erofs_init_device(&buf, sb, dif, &pos); 254 if (err) 255 break; 256 } 257 } 258 up_read(&sbi->devs->rwsem); 259 erofs_put_metabuf(&buf); 260 return err; 261 } 262 263 static int erofs_read_superblock(struct super_block *sb) 264 { 265 struct erofs_sb_info *sbi = EROFS_SB(sb); 266 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 267 struct erofs_super_block *dsb; 268 void *data; 269 int ret; 270 271 data = erofs_read_metabuf(&buf, sb, 0, false); 272 if (IS_ERR(data)) { 273 erofs_err(sb, "cannot read erofs superblock"); 274 return PTR_ERR(data); 275 } 276 277 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET); 278 ret = -EINVAL; 279 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) { 280 erofs_err(sb, "cannot find valid erofs superblock"); 281 goto out; 282 } 283 284 sbi->blkszbits = dsb->blkszbits; 285 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) { 286 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits); 287 goto out; 288 } 289 if (dsb->dirblkbits) { 290 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits); 291 goto out; 292 } 293 294 sbi->feature_compat = le32_to_cpu(dsb->feature_compat); 295 if (erofs_sb_has_sb_chksum(sbi)) { 296 ret = erofs_superblock_csum_verify(sb, data); 297 if (ret) 298 goto out; 299 } 300 301 ret = -EINVAL; 302 sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat); 303 if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) { 304 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel", 305 sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT); 306 goto out; 307 } 308 309 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE; 310 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) { 311 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)", 312 sbi->sb_size); 313 goto out; 314 } 315 sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo); 316 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr); 317 #ifdef CONFIG_EROFS_FS_XATTR 318 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr); 319 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start); 320 sbi->xattr_prefix_count = dsb->xattr_prefix_count; 321 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved; 322 #endif 323 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact)); 324 if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) { 325 sbi->root_nid = le64_to_cpu(dsb->rootnid_8b); 326 sbi->dif0.blocks = sbi->dif0.blocks | 327 ((u64)le16_to_cpu(dsb->rb.blocks_hi) << 32); 328 } else { 329 sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b); 330 } 331 sbi->packed_nid = le64_to_cpu(dsb->packed_nid); 332 if (erofs_sb_has_metabox(sbi)) { 333 if (sbi->sb_size <= offsetof(struct erofs_super_block, 334 metabox_nid)) 335 return -EFSCORRUPTED; 336 sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid); 337 if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT)) 338 return -EFSCORRUPTED; /* self-loop detection */ 339 } 340 sbi->inos = le64_to_cpu(dsb->inos); 341 342 sbi->epoch = (s64)le64_to_cpu(dsb->epoch); 343 sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec); 344 super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid)); 345 346 /* parse on-disk compression configurations */ 347 ret = z_erofs_parse_cfgs(sb, dsb); 348 if (ret < 0) 349 goto out; 350 351 ret = erofs_scan_devices(sb, dsb); 352 353 if (erofs_sb_has_48bit(sbi)) 354 erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!"); 355 if (erofs_sb_has_metabox(sbi)) 356 erofs_info(sb, "EXPERIMENTAL metadata compression support in use. Use at your own risk!"); 357 if (erofs_is_fscache_mode(sb)) 358 erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!"); 359 out: 360 erofs_put_metabuf(&buf); 361 return ret; 362 } 363 364 static void erofs_default_options(struct erofs_sb_info *sbi) 365 { 366 #ifdef CONFIG_EROFS_FS_ZIP 367 sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND; 368 sbi->opt.max_sync_decompress_pages = 3; 369 sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO; 370 #endif 371 #ifdef CONFIG_EROFS_FS_XATTR 372 set_opt(&sbi->opt, XATTR_USER); 373 #endif 374 #ifdef CONFIG_EROFS_FS_POSIX_ACL 375 set_opt(&sbi->opt, POSIX_ACL); 376 #endif 377 } 378 379 enum { 380 Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum, 381 Opt_device, Opt_fsid, Opt_domain_id, Opt_directio, Opt_fsoffset, 382 }; 383 384 static const struct constant_table erofs_param_cache_strategy[] = { 385 {"disabled", EROFS_ZIP_CACHE_DISABLED}, 386 {"readahead", EROFS_ZIP_CACHE_READAHEAD}, 387 {"readaround", EROFS_ZIP_CACHE_READAROUND}, 388 {} 389 }; 390 391 static const struct constant_table erofs_dax_param_enums[] = { 392 {"always", EROFS_MOUNT_DAX_ALWAYS}, 393 {"never", EROFS_MOUNT_DAX_NEVER}, 394 {} 395 }; 396 397 static const struct fs_parameter_spec erofs_fs_parameters[] = { 398 fsparam_flag_no("user_xattr", Opt_user_xattr), 399 fsparam_flag_no("acl", Opt_acl), 400 fsparam_enum("cache_strategy", Opt_cache_strategy, 401 erofs_param_cache_strategy), 402 fsparam_flag("dax", Opt_dax), 403 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums), 404 fsparam_string("device", Opt_device), 405 fsparam_string("fsid", Opt_fsid), 406 fsparam_string("domain_id", Opt_domain_id), 407 fsparam_flag_no("directio", Opt_directio), 408 fsparam_u64("fsoffset", Opt_fsoffset), 409 {} 410 }; 411 412 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode) 413 { 414 #ifdef CONFIG_FS_DAX 415 struct erofs_sb_info *sbi = fc->s_fs_info; 416 417 switch (mode) { 418 case EROFS_MOUNT_DAX_ALWAYS: 419 set_opt(&sbi->opt, DAX_ALWAYS); 420 clear_opt(&sbi->opt, DAX_NEVER); 421 return true; 422 case EROFS_MOUNT_DAX_NEVER: 423 set_opt(&sbi->opt, DAX_NEVER); 424 clear_opt(&sbi->opt, DAX_ALWAYS); 425 return true; 426 default: 427 DBG_BUGON(1); 428 return false; 429 } 430 #else 431 errorfc(fc, "dax options not supported"); 432 return false; 433 #endif 434 } 435 436 static int erofs_fc_parse_param(struct fs_context *fc, 437 struct fs_parameter *param) 438 { 439 struct erofs_sb_info *sbi = fc->s_fs_info; 440 struct fs_parse_result result; 441 struct erofs_device_info *dif; 442 int opt, ret; 443 444 opt = fs_parse(fc, erofs_fs_parameters, param, &result); 445 if (opt < 0) 446 return opt; 447 448 switch (opt) { 449 case Opt_user_xattr: 450 #ifdef CONFIG_EROFS_FS_XATTR 451 if (result.boolean) 452 set_opt(&sbi->opt, XATTR_USER); 453 else 454 clear_opt(&sbi->opt, XATTR_USER); 455 #else 456 errorfc(fc, "{,no}user_xattr options not supported"); 457 #endif 458 break; 459 case Opt_acl: 460 #ifdef CONFIG_EROFS_FS_POSIX_ACL 461 if (result.boolean) 462 set_opt(&sbi->opt, POSIX_ACL); 463 else 464 clear_opt(&sbi->opt, POSIX_ACL); 465 #else 466 errorfc(fc, "{,no}acl options not supported"); 467 #endif 468 break; 469 case Opt_cache_strategy: 470 #ifdef CONFIG_EROFS_FS_ZIP 471 sbi->opt.cache_strategy = result.uint_32; 472 #else 473 errorfc(fc, "compression not supported, cache_strategy ignored"); 474 #endif 475 break; 476 case Opt_dax: 477 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS)) 478 return -EINVAL; 479 break; 480 case Opt_dax_enum: 481 if (!erofs_fc_set_dax_mode(fc, result.uint_32)) 482 return -EINVAL; 483 break; 484 case Opt_device: 485 dif = kzalloc(sizeof(*dif), GFP_KERNEL); 486 if (!dif) 487 return -ENOMEM; 488 dif->path = kstrdup(param->string, GFP_KERNEL); 489 if (!dif->path) { 490 kfree(dif); 491 return -ENOMEM; 492 } 493 down_write(&sbi->devs->rwsem); 494 ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL); 495 up_write(&sbi->devs->rwsem); 496 if (ret < 0) { 497 kfree(dif->path); 498 kfree(dif); 499 return ret; 500 } 501 ++sbi->devs->extra_devices; 502 break; 503 #ifdef CONFIG_EROFS_FS_ONDEMAND 504 case Opt_fsid: 505 kfree(sbi->fsid); 506 sbi->fsid = kstrdup(param->string, GFP_KERNEL); 507 if (!sbi->fsid) 508 return -ENOMEM; 509 break; 510 case Opt_domain_id: 511 kfree(sbi->domain_id); 512 sbi->domain_id = kstrdup(param->string, GFP_KERNEL); 513 if (!sbi->domain_id) 514 return -ENOMEM; 515 break; 516 #else 517 case Opt_fsid: 518 case Opt_domain_id: 519 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name); 520 break; 521 #endif 522 case Opt_directio: 523 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE 524 if (result.boolean) 525 set_opt(&sbi->opt, DIRECT_IO); 526 else 527 clear_opt(&sbi->opt, DIRECT_IO); 528 #else 529 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name); 530 #endif 531 break; 532 case Opt_fsoffset: 533 sbi->dif0.fsoff = result.uint_64; 534 break; 535 } 536 return 0; 537 } 538 539 static int erofs_encode_fh(struct inode *inode, u32 *fh, int *max_len, 540 struct inode *parent) 541 { 542 erofs_nid_t nid = EROFS_I(inode)->nid; 543 int len = parent ? 6 : 3; 544 545 if (*max_len < len) { 546 *max_len = len; 547 return FILEID_INVALID; 548 } 549 550 fh[0] = (u32)(nid >> 32); 551 fh[1] = (u32)(nid & 0xffffffff); 552 fh[2] = inode->i_generation; 553 554 if (parent) { 555 nid = EROFS_I(parent)->nid; 556 557 fh[3] = (u32)(nid >> 32); 558 fh[4] = (u32)(nid & 0xffffffff); 559 fh[5] = parent->i_generation; 560 } 561 562 *max_len = len; 563 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN; 564 } 565 566 static struct dentry *erofs_fh_to_dentry(struct super_block *sb, 567 struct fid *fid, int fh_len, int fh_type) 568 { 569 if ((fh_type != FILEID_INO64_GEN && 570 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3) 571 return NULL; 572 573 return d_obtain_alias(erofs_iget(sb, 574 ((u64)fid->raw[0] << 32) | fid->raw[1])); 575 } 576 577 static struct dentry *erofs_fh_to_parent(struct super_block *sb, 578 struct fid *fid, int fh_len, int fh_type) 579 { 580 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6) 581 return NULL; 582 583 return d_obtain_alias(erofs_iget(sb, 584 ((u64)fid->raw[3] << 32) | fid->raw[4])); 585 } 586 587 static struct dentry *erofs_get_parent(struct dentry *child) 588 { 589 erofs_nid_t nid; 590 unsigned int d_type; 591 int err; 592 593 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type); 594 if (err) 595 return ERR_PTR(err); 596 return d_obtain_alias(erofs_iget(child->d_sb, nid)); 597 } 598 599 static const struct export_operations erofs_export_ops = { 600 .encode_fh = erofs_encode_fh, 601 .fh_to_dentry = erofs_fh_to_dentry, 602 .fh_to_parent = erofs_fh_to_parent, 603 .get_parent = erofs_get_parent, 604 }; 605 606 static void erofs_set_sysfs_name(struct super_block *sb) 607 { 608 struct erofs_sb_info *sbi = EROFS_SB(sb); 609 610 if (sbi->domain_id) 611 super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id, 612 sbi->fsid); 613 else if (sbi->fsid) 614 super_set_sysfs_name_generic(sb, "%s", sbi->fsid); 615 else if (erofs_is_fileio_mode(sbi)) 616 super_set_sysfs_name_generic(sb, "%s", 617 bdi_dev_name(sb->s_bdi)); 618 else 619 super_set_sysfs_name_id(sb); 620 } 621 622 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) 623 { 624 struct inode *inode; 625 struct erofs_sb_info *sbi = EROFS_SB(sb); 626 int err; 627 628 sb->s_magic = EROFS_SUPER_MAGIC; 629 sb->s_flags |= SB_RDONLY | SB_NOATIME; 630 sb->s_maxbytes = MAX_LFS_FILESIZE; 631 sb->s_op = &erofs_sops; 632 633 sbi->blkszbits = PAGE_SHIFT; 634 if (!sb->s_bdev) { 635 sb->s_blocksize = PAGE_SIZE; 636 sb->s_blocksize_bits = PAGE_SHIFT; 637 638 if (erofs_is_fscache_mode(sb)) { 639 err = erofs_fscache_register_fs(sb); 640 if (err) 641 return err; 642 } 643 err = super_setup_bdi(sb); 644 if (err) 645 return err; 646 } else { 647 if (!sb_set_blocksize(sb, PAGE_SIZE)) { 648 errorfc(fc, "failed to set initial blksize"); 649 return -EINVAL; 650 } 651 652 sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev, 653 &sbi->dif0.dax_part_off, NULL, NULL); 654 } 655 656 err = erofs_read_superblock(sb); 657 if (err) 658 return err; 659 660 if (sb->s_blocksize_bits != sbi->blkszbits) { 661 if (erofs_is_fscache_mode(sb)) { 662 errorfc(fc, "unsupported blksize for fscache mode"); 663 return -EINVAL; 664 } 665 666 if (erofs_is_fileio_mode(sbi)) { 667 sb->s_blocksize = 1 << sbi->blkszbits; 668 sb->s_blocksize_bits = sbi->blkszbits; 669 } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) { 670 errorfc(fc, "failed to set erofs blksize"); 671 return -EINVAL; 672 } 673 } 674 675 if (sbi->dif0.fsoff) { 676 if (sbi->dif0.fsoff & (sb->s_blocksize - 1)) 677 return invalfc(fc, "fsoffset %llu is not aligned to block size %lu", 678 sbi->dif0.fsoff, sb->s_blocksize); 679 if (erofs_is_fscache_mode(sb)) 680 return invalfc(fc, "cannot use fsoffset in fscache mode"); 681 } 682 683 if (test_opt(&sbi->opt, DAX_ALWAYS) && sbi->blkszbits != PAGE_SHIFT) { 684 erofs_info(sb, "unsupported blocksize for DAX"); 685 clear_opt(&sbi->opt, DAX_ALWAYS); 686 } 687 688 sb->s_time_gran = 1; 689 sb->s_xattr = erofs_xattr_handlers; 690 sb->s_export_op = &erofs_export_ops; 691 692 if (test_opt(&sbi->opt, POSIX_ACL)) 693 sb->s_flags |= SB_POSIXACL; 694 else 695 sb->s_flags &= ~SB_POSIXACL; 696 697 err = z_erofs_init_super(sb); 698 if (err) 699 return err; 700 701 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) { 702 inode = erofs_iget(sb, sbi->packed_nid); 703 if (IS_ERR(inode)) 704 return PTR_ERR(inode); 705 sbi->packed_inode = inode; 706 } 707 if (erofs_sb_has_metabox(sbi)) { 708 inode = erofs_iget(sb, sbi->metabox_nid); 709 if (IS_ERR(inode)) 710 return PTR_ERR(inode); 711 sbi->metabox_inode = inode; 712 } 713 714 inode = erofs_iget(sb, sbi->root_nid); 715 if (IS_ERR(inode)) 716 return PTR_ERR(inode); 717 718 if (!S_ISDIR(inode->i_mode)) { 719 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)", 720 sbi->root_nid, inode->i_mode); 721 iput(inode); 722 return -EINVAL; 723 } 724 sb->s_root = d_make_root(inode); 725 if (!sb->s_root) 726 return -ENOMEM; 727 728 erofs_shrinker_register(sb); 729 err = erofs_xattr_prefixes_init(sb); 730 if (err) 731 return err; 732 733 erofs_set_sysfs_name(sb); 734 err = erofs_register_sysfs(sb); 735 if (err) 736 return err; 737 738 sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES; 739 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid); 740 return 0; 741 } 742 743 static int erofs_fc_get_tree(struct fs_context *fc) 744 { 745 struct erofs_sb_info *sbi = fc->s_fs_info; 746 int ret; 747 748 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) 749 return get_tree_nodev(fc, erofs_fc_fill_super); 750 751 ret = get_tree_bdev_flags(fc, erofs_fc_fill_super, 752 IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ? 753 GET_TREE_BDEV_QUIET_LOOKUP : 0); 754 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE 755 if (ret == -ENOTBLK) { 756 struct file *file; 757 758 if (!fc->source) 759 return invalf(fc, "No source specified"); 760 file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0); 761 if (IS_ERR(file)) 762 return PTR_ERR(file); 763 sbi->dif0.file = file; 764 765 if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) && 766 sbi->dif0.file->f_mapping->a_ops->read_folio) 767 return get_tree_nodev(fc, erofs_fc_fill_super); 768 } 769 #endif 770 return ret; 771 } 772 773 static int erofs_fc_reconfigure(struct fs_context *fc) 774 { 775 struct super_block *sb = fc->root->d_sb; 776 struct erofs_sb_info *sbi = EROFS_SB(sb); 777 struct erofs_sb_info *new_sbi = fc->s_fs_info; 778 779 DBG_BUGON(!sb_rdonly(sb)); 780 781 if (new_sbi->fsid || new_sbi->domain_id) 782 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id."); 783 784 if (test_opt(&new_sbi->opt, POSIX_ACL)) 785 fc->sb_flags |= SB_POSIXACL; 786 else 787 fc->sb_flags &= ~SB_POSIXACL; 788 789 sbi->opt = new_sbi->opt; 790 791 fc->sb_flags |= SB_RDONLY; 792 return 0; 793 } 794 795 static int erofs_release_device_info(int id, void *ptr, void *data) 796 { 797 struct erofs_device_info *dif = ptr; 798 799 fs_put_dax(dif->dax_dev, NULL); 800 if (dif->file) 801 fput(dif->file); 802 erofs_fscache_unregister_cookie(dif->fscache); 803 dif->fscache = NULL; 804 kfree(dif->path); 805 kfree(dif); 806 return 0; 807 } 808 809 static void erofs_free_dev_context(struct erofs_dev_context *devs) 810 { 811 if (!devs) 812 return; 813 idr_for_each(&devs->tree, &erofs_release_device_info, NULL); 814 idr_destroy(&devs->tree); 815 kfree(devs); 816 } 817 818 static void erofs_sb_free(struct erofs_sb_info *sbi) 819 { 820 erofs_free_dev_context(sbi->devs); 821 kfree(sbi->fsid); 822 kfree(sbi->domain_id); 823 if (sbi->dif0.file) 824 fput(sbi->dif0.file); 825 kfree(sbi); 826 } 827 828 static void erofs_fc_free(struct fs_context *fc) 829 { 830 struct erofs_sb_info *sbi = fc->s_fs_info; 831 832 if (sbi) /* free here if an error occurs before transferring to sb */ 833 erofs_sb_free(sbi); 834 } 835 836 static const struct fs_context_operations erofs_context_ops = { 837 .parse_param = erofs_fc_parse_param, 838 .get_tree = erofs_fc_get_tree, 839 .reconfigure = erofs_fc_reconfigure, 840 .free = erofs_fc_free, 841 }; 842 843 static int erofs_init_fs_context(struct fs_context *fc) 844 { 845 struct erofs_sb_info *sbi; 846 847 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); 848 if (!sbi) 849 return -ENOMEM; 850 851 sbi->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL); 852 if (!sbi->devs) { 853 kfree(sbi); 854 return -ENOMEM; 855 } 856 fc->s_fs_info = sbi; 857 858 idr_init(&sbi->devs->tree); 859 init_rwsem(&sbi->devs->rwsem); 860 erofs_default_options(sbi); 861 fc->ops = &erofs_context_ops; 862 return 0; 863 } 864 865 static void erofs_drop_internal_inodes(struct erofs_sb_info *sbi) 866 { 867 iput(sbi->packed_inode); 868 sbi->packed_inode = NULL; 869 iput(sbi->metabox_inode); 870 sbi->metabox_inode = NULL; 871 #ifdef CONFIG_EROFS_FS_ZIP 872 iput(sbi->managed_cache); 873 sbi->managed_cache = NULL; 874 #endif 875 } 876 877 static void erofs_kill_sb(struct super_block *sb) 878 { 879 struct erofs_sb_info *sbi = EROFS_SB(sb); 880 881 if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) || 882 sbi->dif0.file) 883 kill_anon_super(sb); 884 else 885 kill_block_super(sb); 886 erofs_drop_internal_inodes(sbi); 887 fs_put_dax(sbi->dif0.dax_dev, NULL); 888 erofs_fscache_unregister_fs(sb); 889 erofs_sb_free(sbi); 890 sb->s_fs_info = NULL; 891 } 892 893 static void erofs_put_super(struct super_block *sb) 894 { 895 struct erofs_sb_info *const sbi = EROFS_SB(sb); 896 897 erofs_unregister_sysfs(sb); 898 erofs_shrinker_unregister(sb); 899 erofs_xattr_prefixes_cleanup(sb); 900 erofs_drop_internal_inodes(sbi); 901 erofs_free_dev_context(sbi->devs); 902 sbi->devs = NULL; 903 erofs_fscache_unregister_fs(sb); 904 } 905 906 static struct file_system_type erofs_fs_type = { 907 .owner = THIS_MODULE, 908 .name = "erofs", 909 .init_fs_context = erofs_init_fs_context, 910 .kill_sb = erofs_kill_sb, 911 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, 912 }; 913 MODULE_ALIAS_FS("erofs"); 914 915 static int __init erofs_module_init(void) 916 { 917 int err; 918 919 erofs_check_ondisk_layout_definitions(); 920 921 erofs_inode_cachep = kmem_cache_create("erofs_inode", 922 sizeof(struct erofs_inode), 0, 923 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT, 924 erofs_inode_init_once); 925 if (!erofs_inode_cachep) 926 return -ENOMEM; 927 928 err = erofs_init_shrinker(); 929 if (err) 930 goto shrinker_err; 931 932 err = z_erofs_init_subsystem(); 933 if (err) 934 goto zip_err; 935 936 err = erofs_init_sysfs(); 937 if (err) 938 goto sysfs_err; 939 940 err = register_filesystem(&erofs_fs_type); 941 if (err) 942 goto fs_err; 943 944 return 0; 945 946 fs_err: 947 erofs_exit_sysfs(); 948 sysfs_err: 949 z_erofs_exit_subsystem(); 950 zip_err: 951 erofs_exit_shrinker(); 952 shrinker_err: 953 kmem_cache_destroy(erofs_inode_cachep); 954 return err; 955 } 956 957 static void __exit erofs_module_exit(void) 958 { 959 unregister_filesystem(&erofs_fs_type); 960 961 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */ 962 rcu_barrier(); 963 964 erofs_exit_sysfs(); 965 z_erofs_exit_subsystem(); 966 erofs_exit_shrinker(); 967 kmem_cache_destroy(erofs_inode_cachep); 968 } 969 970 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf) 971 { 972 struct super_block *sb = dentry->d_sb; 973 struct erofs_sb_info *sbi = EROFS_SB(sb); 974 975 buf->f_type = sb->s_magic; 976 buf->f_bsize = sb->s_blocksize; 977 buf->f_blocks = sbi->total_blocks; 978 buf->f_bfree = buf->f_bavail = 0; 979 buf->f_files = ULLONG_MAX; 980 buf->f_ffree = ULLONG_MAX - sbi->inos; 981 buf->f_namelen = EROFS_NAME_LEN; 982 983 if (uuid_is_null(&sb->s_uuid)) 984 buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 : 985 huge_encode_dev(sb->s_bdev->bd_dev)); 986 else 987 buf->f_fsid = uuid_to_fsid(sb->s_uuid.b); 988 return 0; 989 } 990 991 static int erofs_show_options(struct seq_file *seq, struct dentry *root) 992 { 993 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb); 994 struct erofs_mount_opts *opt = &sbi->opt; 995 996 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR)) 997 seq_puts(seq, test_opt(opt, XATTR_USER) ? 998 ",user_xattr" : ",nouser_xattr"); 999 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL)) 1000 seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl"); 1001 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP)) 1002 seq_printf(seq, ",cache_strategy=%s", 1003 erofs_param_cache_strategy[opt->cache_strategy].name); 1004 if (test_opt(opt, DAX_ALWAYS)) 1005 seq_puts(seq, ",dax=always"); 1006 if (test_opt(opt, DAX_NEVER)) 1007 seq_puts(seq, ",dax=never"); 1008 if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO)) 1009 seq_puts(seq, ",directio"); 1010 #ifdef CONFIG_EROFS_FS_ONDEMAND 1011 if (sbi->fsid) 1012 seq_printf(seq, ",fsid=%s", sbi->fsid); 1013 if (sbi->domain_id) 1014 seq_printf(seq, ",domain_id=%s", sbi->domain_id); 1015 #endif 1016 if (sbi->dif0.fsoff) 1017 seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff); 1018 return 0; 1019 } 1020 1021 const struct super_operations erofs_sops = { 1022 .put_super = erofs_put_super, 1023 .alloc_inode = erofs_alloc_inode, 1024 .free_inode = erofs_free_inode, 1025 .statfs = erofs_statfs, 1026 .show_options = erofs_show_options, 1027 }; 1028 1029 module_init(erofs_module_init); 1030 module_exit(erofs_module_exit); 1031 1032 MODULE_DESCRIPTION("Enhanced ROM File System"); 1033 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc."); 1034 MODULE_LICENSE("GPL"); 1035