2 * openfs.c --- open an ext2 filesystem
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
24 #include <sys/types.h>
35 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block,
39 int has_super = 0, group_zero_adjust = 0;
43 * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4
44 * stuff, so adjust for that if we're being asked for group 0.
46 if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1)
47 group_zero_adjust = 1;
49 if (!ext2fs_has_feature_meta_bg(fs->super) ||
50 (i < fs->super->s_first_meta_bg))
51 return group_block + i + 1 + group_zero_adjust;
53 bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
54 if (ext2fs_bg_has_super(fs, bg))
56 ret_blk = ext2fs_group_first_block2(fs, bg);
58 * If group_block is not the normal value, we're trying to use
59 * the backup group descriptors and superblock --- so use the
60 * alternate location of the second block group in the
61 * metablock group. Ideally we should be testing each bg
62 * descriptor block individually for correctness, but we don't
63 * have the infrastructure in place to do that.
65 if (group_block != fs->super->s_first_data_block &&
66 ((ret_blk + has_super + fs->super->s_blocks_per_group) <
67 ext2fs_blocks_count(fs->super))) {
68 ret_blk += fs->super->s_blocks_per_group;
71 * If we're going to jump forward a block group, make sure
72 * that we adjust has_super to account for the next group's
73 * backup superblock (or lack thereof).
75 if (ext2fs_bg_has_super(fs, bg + 1))
80 return ret_blk + has_super + group_zero_adjust;
83 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
85 return ext2fs_descriptor_block_loc2(fs, group_block, i);
88 errcode_t ext2fs_open(const char *name, int flags, int superblock,
89 unsigned int block_size, io_manager manager,
92 return ext2fs_open2(name, 0, flags, superblock, block_size,
96 static void block_sha_map_free_entry(void *data)
103 * Note: if superblock is non-zero, block-size must also be non-zero.
104 * Superblock and block_size can be zero to use the default size.
106 * Valid flags for ext2fs_open()
108 * EXT2_FLAG_RW - Open the filesystem for read/write.
109 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
110 * features aren't supported.
111 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
112 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
113 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
116 errcode_t ext2fs_open2(const char *name, const char *io_options,
117 int flags, int superblock,
118 unsigned int block_size, io_manager manager,
123 unsigned long i, first_meta_bg;
125 unsigned int blocks_per_group, io_flags;
126 blk64_t group_block, blk;
128 int group_zero_adjust = 0;
129 unsigned int inode_size;
131 #ifdef WORDS_BIGENDIAN
132 unsigned int groups_per_block;
133 struct ext2_group_desc *gdp;
137 int csum_retries = 0;
139 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
141 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
145 memset(fs, 0, sizeof(struct struct_ext2_filsys));
146 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
148 /* don't overwrite sb backups unless flag is explicitly cleared */
149 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
152 time_env = getenv("E2FSPROGS_FAKE_TIME");
154 fs->now = strtoul(time_env, NULL, 0);
156 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
159 strcpy(fs->device_name, name);
160 cp = strchr(fs->device_name, '?');
161 if (!io_options && cp) {
167 if (flags & EXT2_FLAG_RW)
168 io_flags |= IO_FLAG_RW;
169 if (flags & EXT2_FLAG_EXCLUSIVE)
170 io_flags |= IO_FLAG_EXCLUSIVE;
171 if (flags & EXT2_FLAG_DIRECT_IO)
172 io_flags |= IO_FLAG_DIRECT_IO;
173 retval = manager->open(fs->device_name, io_flags, &fs->io);
177 (retval = io_channel_set_options(fs->io, io_options)))
179 fs->image_io = fs->io;
180 fs->io->app_data = fs;
181 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
184 if (flags & EXT2_FLAG_IMAGE_FILE) {
185 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
189 retval = io_channel_read_blk(fs->io, 0,
190 -(int)sizeof(struct ext2_image_hdr),
194 if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE)
195 return EXT2_ET_MAGIC_E2IMAGE;
197 block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize);
201 * If the user specifies a specific block # for the
202 * superblock, then he/she must also specify the block size!
203 * Otherwise, read the master superblock located at offset
204 * SUPERBLOCK_OFFSET from the start of the partition.
206 * Note: we only save a backup copy of the superblock if we
207 * are reading the superblock from the primary superblock location.
211 retval = EXT2_ET_INVALID_ARGUMENT;
214 io_channel_set_blksize(fs->io, block_size);
215 group_block = superblock;
218 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
221 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
226 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
231 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
233 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
235 if (!ext2fs_verify_csum_type(fs, fs->super))
236 retval = EXT2_ET_UNKNOWN_CSUM;
237 if (!ext2fs_superblock_csum_verify(fs, fs->super)) {
238 if (csum_retries++ < 3)
240 retval = EXT2_ET_SB_CSUM_INVALID;
244 #ifdef WORDS_BIGENDIAN
245 fs->flags |= EXT2_FLAG_SWAP_BYTES;
246 ext2fs_swap_super(fs->super);
248 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
249 retval = EXT2_ET_UNIMPLEMENTED;
254 if (fs->super->s_magic != EXT2_SUPER_MAGIC)
255 retval = EXT2_ET_BAD_MAGIC;
259 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
260 retval = EXT2_ET_REV_TOO_HIGH;
265 * Check for feature set incompatibility
267 if (!(flags & EXT2_FLAG_FORCE)) {
268 features = fs->super->s_feature_incompat;
269 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
270 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
271 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
273 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
274 retval = EXT2_ET_UNSUPP_FEATURE;
278 features = fs->super->s_feature_ro_compat;
279 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
280 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
281 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
283 if ((flags & EXT2_FLAG_RW) &&
284 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
285 retval = EXT2_ET_RO_UNSUPP_FEATURE;
289 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
290 ext2fs_has_feature_journal_dev(fs->super)) {
291 retval = EXT2_ET_UNSUPP_FEATURE;
296 if (fs->super->s_log_block_size >
297 (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) {
298 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
303 * bigalloc requires cluster-aware bitfield operations, which at the
304 * moment means we need EXT2_FLAG_64BITS.
306 if (ext2fs_has_feature_bigalloc(fs->super) &&
307 !(flags & EXT2_FLAG_64BITS)) {
308 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
312 if (!ext2fs_has_feature_bigalloc(fs->super) &&
313 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
314 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
317 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
318 inode_size = EXT2_INODE_SIZE(fs->super);
319 if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
320 (inode_size > fs->blocksize) ||
321 (inode_size & (inode_size - 1))) {
322 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
326 /* Enforce the block group descriptor size */
327 if (ext2fs_has_feature_64bit(fs->super)) {
328 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) {
329 retval = EXT2_ET_BAD_DESC_SIZE;
334 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
335 fs->super->s_log_block_size;
336 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
337 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
338 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
341 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
342 EXT2_INODE_SIZE(fs->super) +
343 EXT2_BLOCK_SIZE(fs->super) - 1) /
344 EXT2_BLOCK_SIZE(fs->super));
346 if (block_size != fs->blocksize) {
347 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
352 * Set the blocksize to the filesystem's blocksize.
354 io_channel_set_blksize(fs->io, fs->blocksize);
357 * If this is an external journal device, don't try to read
358 * the group descriptors, because they're not there.
360 if (ext2fs_has_feature_journal_dev(fs->super)) {
361 fs->group_desc_count = 0;
366 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
367 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
370 /* Precompute the FS UUID to seed other checksums */
371 ext2fs_init_csum_seed(fs);
374 * Read group descriptors
376 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
377 if (blocks_per_group == 0 ||
378 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
379 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
380 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
381 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
382 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
385 groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
386 fs->super->s_first_data_block,
388 if (groups_cnt >> 32) {
389 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
392 fs->group_desc_count = groups_cnt;
393 if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
394 (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
395 fs->super->s_inodes_count) {
396 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
399 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
400 EXT2_DESC_PER_BLOCK(fs->super));
401 if (flags & EXT2_FLAG_SUPER_ONLY)
403 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
408 group_block = fs->super->s_first_data_block;
410 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
411 * so we must increment block numbers to any group 0 items.
413 * However, we cannot touch group_block directly because in the meta_bg
414 * case, the ext2fs_descriptor_block_loc2() function will interpret
415 * group_block != s_first_data_block to mean that we want to access the
416 * backup group descriptors. This is not what we want if the caller
417 * set superblock == 0 (i.e. auto-detect the superblock), which is
418 * what's going on here.
420 if (group_block == 0 && fs->blocksize == 1024)
421 group_zero_adjust = 1;
422 dest = (char *) fs->group_desc;
423 #ifdef WORDS_BIGENDIAN
424 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
426 if (ext2fs_has_feature_meta_bg(fs->super) &&
427 !(flags & EXT2_FLAG_IMAGE_FILE)) {
428 first_meta_bg = fs->super->s_first_meta_bg;
429 if (first_meta_bg > fs->desc_blocks)
430 first_meta_bg = fs->desc_blocks;
432 first_meta_bg = fs->desc_blocks;
434 retval = io_channel_read_blk(fs->io, group_block +
435 group_zero_adjust + 1,
436 first_meta_bg, dest);
439 #ifdef WORDS_BIGENDIAN
440 gdp = (struct ext2_group_desc *) dest;
441 for (j=0; j < groups_per_block*first_meta_bg; j++) {
442 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
444 ext2fs_swap_group_desc2(fs, gdp);
447 dest += fs->blocksize*first_meta_bg;
450 for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
451 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
452 io_channel_cache_readahead(fs->io, blk, 1);
455 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
456 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
457 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
460 #ifdef WORDS_BIGENDIAN
461 for (j=0; j < groups_per_block; j++) {
462 gdp = ext2fs_group_desc(fs, fs->group_desc,
463 i * groups_per_block + j);
465 ext2fs_swap_group_desc2(fs, gdp);
468 dest += fs->blocksize;
471 fs->stride = fs->super->s_raid_stride;
474 * If recovery is from backup superblock, Clear _UNININT flags &
475 * reset bg_itable_unused to zero
477 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
480 for (group = 0; group < fs->group_desc_count; group++) {
481 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
482 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
483 ext2fs_bg_itable_unused_set(fs, group, 0);
484 /* The checksum will be reset later, but fix it here
485 * anyway to avoid printing a lot of spurious errors. */
486 ext2fs_group_desc_csum_set(fs, group);
488 if (fs->flags & EXT2_FLAG_RW)
489 ext2fs_mark_super_dirty(fs);
492 if (ext2fs_has_feature_mmp(fs->super) &&
493 !(flags & EXT2_FLAG_SKIP_MMP) &&
494 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
495 retval = ext2fs_mmp_start(fs);
497 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
503 if (fs->flags & EXT2_FLAG_SHARE_DUP) {
504 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
505 block_sha_map_free_entry, 4096);
506 if (!fs->block_sha_map) {
507 retval = EXT2_ET_NO_MEMORY;
510 ext2fs_set_feature_shared_blocks(fs->super);
513 if (ext2fs_has_feature_casefold(fs->super))
514 fs->encoding = ext2fs_load_nls_table(fs->super->s_encoding);
516 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
521 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
530 * Set/get the filesystem data I/O channel.
532 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
534 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
536 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
537 return EXT2_ET_NOT_IMAGE_FILE;
539 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
544 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
546 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
547 return EXT2_ET_NOT_IMAGE_FILE;
548 fs->io = new_io ? new_io : fs->image_io;
552 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
556 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
557 return EXT2_ET_NOT_IMAGE_FILE;
558 err = io_channel_set_blksize(new_io, fs->blocksize);
561 if ((new_io == fs->image_io) || (new_io == fs->io))
563 if ((fs->image_io != fs->io) &&
565 io_channel_close(fs->image_io);
567 io_channel_close(fs->io);
568 fs->io = fs->image_io = new_io;
569 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
570 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
571 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;