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
;
138 EXT2_CHECK_MAGIC(manager
, EXT2_ET_MAGIC_IO_MANAGER
);
140 retval
= ext2fs_get_mem(sizeof(struct struct_ext2_filsys
), &fs
);
144 memset(fs
, 0, sizeof(struct struct_ext2_filsys
));
145 fs
->magic
= EXT2_ET_MAGIC_EXT2FS_FILSYS
;
147 /* don't overwrite sb backups unless flag is explicitly cleared */
148 fs
->flags
|= EXT2_FLAG_MASTER_SB_ONLY
;
151 time_env
= getenv("E2FSPROGS_FAKE_TIME");
153 fs
->now
= strtoul(time_env
, NULL
, 0);
155 retval
= ext2fs_get_mem(strlen(name
)+1, &fs
->device_name
);
158 strcpy(fs
->device_name
, name
);
159 cp
= strchr(fs
->device_name
, '?');
160 if (!io_options
&& cp
) {
166 if (flags
& EXT2_FLAG_RW
)
167 io_flags
|= IO_FLAG_RW
;
168 if (flags
& EXT2_FLAG_EXCLUSIVE
)
169 io_flags
|= IO_FLAG_EXCLUSIVE
;
170 if (flags
& EXT2_FLAG_DIRECT_IO
)
171 io_flags
|= IO_FLAG_DIRECT_IO
;
172 retval
= manager
->open(fs
->device_name
, io_flags
, &fs
->io
);
176 (retval
= io_channel_set_options(fs
->io
, io_options
)))
178 fs
->image_io
= fs
->io
;
179 fs
->io
->app_data
= fs
;
180 retval
= io_channel_alloc_buf(fs
->io
, -SUPERBLOCK_SIZE
, &fs
->super
);
183 if (flags
& EXT2_FLAG_IMAGE_FILE
) {
184 retval
= ext2fs_get_mem(sizeof(struct ext2_image_hdr
),
188 retval
= io_channel_read_blk(fs
->io
, 0,
189 -(int)sizeof(struct ext2_image_hdr
),
193 if (ext2fs_le32_to_cpu(fs
->image_header
->magic_number
) != EXT2_ET_MAGIC_E2IMAGE
)
194 return EXT2_ET_MAGIC_E2IMAGE
;
196 block_size
= ext2fs_le32_to_cpu(fs
->image_header
->fs_blocksize
);
200 * If the user specifies a specific block # for the
201 * superblock, then he/she must also specify the block size!
202 * Otherwise, read the master superblock located at offset
203 * SUPERBLOCK_OFFSET from the start of the partition.
205 * Note: we only save a backup copy of the superblock if we
206 * are reading the superblock from the primary superblock location.
210 retval
= EXT2_ET_INVALID_ARGUMENT
;
213 io_channel_set_blksize(fs
->io
, block_size
);
214 group_block
= superblock
;
217 io_channel_set_blksize(fs
->io
, SUPERBLOCK_OFFSET
);
220 retval
= ext2fs_get_mem(SUPERBLOCK_SIZE
, &fs
->orig_super
);
224 retval
= io_channel_read_blk(fs
->io
, superblock
, -SUPERBLOCK_SIZE
,
229 memcpy(fs
->orig_super
, fs
->super
, SUPERBLOCK_SIZE
);
231 if (!(fs
->flags
& EXT2_FLAG_IGNORE_CSUM_ERRORS
)) {
233 if (!ext2fs_verify_csum_type(fs
, fs
->super
))
234 retval
= EXT2_ET_UNKNOWN_CSUM
;
235 if (!ext2fs_superblock_csum_verify(fs
, fs
->super
))
236 retval
= EXT2_ET_SB_CSUM_INVALID
;
239 #ifdef WORDS_BIGENDIAN
240 fs
->flags
|= EXT2_FLAG_SWAP_BYTES
;
241 ext2fs_swap_super(fs
->super
);
243 if (fs
->flags
& EXT2_FLAG_SWAP_BYTES
) {
244 retval
= EXT2_ET_UNIMPLEMENTED
;
249 if (fs
->super
->s_magic
!= EXT2_SUPER_MAGIC
)
250 retval
= EXT2_ET_BAD_MAGIC
;
254 if (fs
->super
->s_rev_level
> EXT2_LIB_CURRENT_REV
) {
255 retval
= EXT2_ET_REV_TOO_HIGH
;
260 * Check for feature set incompatibility
262 if (!(flags
& EXT2_FLAG_FORCE
)) {
263 features
= fs
->super
->s_feature_incompat
;
264 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
265 if (flags
& EXT2_FLAG_SOFTSUPP_FEATURES
)
266 features
&= ~EXT2_LIB_SOFTSUPP_INCOMPAT
;
268 if (features
& ~EXT2_LIB_FEATURE_INCOMPAT_SUPP
) {
269 retval
= EXT2_ET_UNSUPP_FEATURE
;
273 features
= fs
->super
->s_feature_ro_compat
;
274 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
275 if (flags
& EXT2_FLAG_SOFTSUPP_FEATURES
)
276 features
&= ~EXT2_LIB_SOFTSUPP_RO_COMPAT
;
278 if ((flags
& EXT2_FLAG_RW
) &&
279 (features
& ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP
)) {
280 retval
= EXT2_ET_RO_UNSUPP_FEATURE
;
284 if (!(flags
& EXT2_FLAG_JOURNAL_DEV_OK
) &&
285 ext2fs_has_feature_journal_dev(fs
->super
)) {
286 retval
= EXT2_ET_UNSUPP_FEATURE
;
291 if (fs
->super
->s_log_block_size
>
292 (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE
- EXT2_MIN_BLOCK_LOG_SIZE
)) {
293 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
298 * bigalloc requires cluster-aware bitfield operations, which at the
299 * moment means we need EXT2_FLAG_64BITS.
301 if (ext2fs_has_feature_bigalloc(fs
->super
) &&
302 !(flags
& EXT2_FLAG_64BITS
)) {
303 retval
= EXT2_ET_CANT_USE_LEGACY_BITMAPS
;
307 if (!ext2fs_has_feature_bigalloc(fs
->super
) &&
308 (fs
->super
->s_log_block_size
!= fs
->super
->s_log_cluster_size
)) {
309 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
312 fs
->fragsize
= fs
->blocksize
= EXT2_BLOCK_SIZE(fs
->super
);
313 inode_size
= EXT2_INODE_SIZE(fs
->super
);
314 if ((inode_size
< EXT2_GOOD_OLD_INODE_SIZE
) ||
315 (inode_size
> fs
->blocksize
) ||
316 (inode_size
& (inode_size
- 1))) {
317 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
321 /* Enforce the block group descriptor size */
322 if (ext2fs_has_feature_64bit(fs
->super
)) {
323 if (fs
->super
->s_desc_size
< EXT2_MIN_DESC_SIZE_64BIT
) {
324 retval
= EXT2_ET_BAD_DESC_SIZE
;
329 fs
->cluster_ratio_bits
= fs
->super
->s_log_cluster_size
-
330 fs
->super
->s_log_block_size
;
331 if (EXT2_BLOCKS_PER_GROUP(fs
->super
) !=
332 EXT2_CLUSTERS_PER_GROUP(fs
->super
) << fs
->cluster_ratio_bits
) {
333 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
336 fs
->inode_blocks_per_group
= ((EXT2_INODES_PER_GROUP(fs
->super
) *
337 EXT2_INODE_SIZE(fs
->super
) +
338 EXT2_BLOCK_SIZE(fs
->super
) - 1) /
339 EXT2_BLOCK_SIZE(fs
->super
));
341 if (block_size
!= fs
->blocksize
) {
342 retval
= EXT2_ET_UNEXPECTED_BLOCK_SIZE
;
347 * Set the blocksize to the filesystem's blocksize.
349 io_channel_set_blksize(fs
->io
, fs
->blocksize
);
352 * If this is an external journal device, don't try to read
353 * the group descriptors, because they're not there.
355 if (ext2fs_has_feature_journal_dev(fs
->super
)) {
356 fs
->group_desc_count
= 0;
361 if (EXT2_INODES_PER_GROUP(fs
->super
) == 0) {
362 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
365 /* Precompute the FS UUID to seed other checksums */
366 ext2fs_init_csum_seed(fs
);
369 * Read group descriptors
371 blocks_per_group
= EXT2_BLOCKS_PER_GROUP(fs
->super
);
372 if (blocks_per_group
== 0 ||
373 blocks_per_group
> EXT2_MAX_BLOCKS_PER_GROUP(fs
->super
) ||
374 fs
->inode_blocks_per_group
> EXT2_MAX_INODES_PER_GROUP(fs
->super
) ||
375 EXT2_DESC_PER_BLOCK(fs
->super
) == 0 ||
376 fs
->super
->s_first_data_block
>= ext2fs_blocks_count(fs
->super
)) {
377 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
380 groups_cnt
= ext2fs_div64_ceil(ext2fs_blocks_count(fs
->super
) -
381 fs
->super
->s_first_data_block
,
383 if (groups_cnt
>> 32) {
384 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
387 fs
->group_desc_count
= groups_cnt
;
388 if (!(flags
& EXT2_FLAG_IGNORE_SB_ERRORS
) &&
389 (__u64
)fs
->group_desc_count
* EXT2_INODES_PER_GROUP(fs
->super
) !=
390 fs
->super
->s_inodes_count
) {
391 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
394 fs
->desc_blocks
= ext2fs_div_ceil(fs
->group_desc_count
,
395 EXT2_DESC_PER_BLOCK(fs
->super
));
396 retval
= ext2fs_get_array(fs
->desc_blocks
, fs
->blocksize
,
401 group_block
= fs
->super
->s_first_data_block
;
403 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
404 * so we must increment block numbers to any group 0 items.
406 * However, we cannot touch group_block directly because in the meta_bg
407 * case, the ext2fs_descriptor_block_loc2() function will interpret
408 * group_block != s_first_data_block to mean that we want to access the
409 * backup group descriptors. This is not what we want if the caller
410 * set superblock == 0 (i.e. auto-detect the superblock), which is
411 * what's going on here.
413 if (group_block
== 0 && fs
->blocksize
== 1024)
414 group_zero_adjust
= 1;
415 dest
= (char *) fs
->group_desc
;
416 #ifdef WORDS_BIGENDIAN
417 groups_per_block
= EXT2_DESC_PER_BLOCK(fs
->super
);
419 if (ext2fs_has_feature_meta_bg(fs
->super
) &&
420 !(flags
& EXT2_FLAG_IMAGE_FILE
)) {
421 first_meta_bg
= fs
->super
->s_first_meta_bg
;
422 if (first_meta_bg
> fs
->desc_blocks
)
423 first_meta_bg
= fs
->desc_blocks
;
425 first_meta_bg
= fs
->desc_blocks
;
427 retval
= io_channel_read_blk(fs
->io
, group_block
+
428 group_zero_adjust
+ 1,
429 first_meta_bg
, dest
);
432 #ifdef WORDS_BIGENDIAN
433 gdp
= (struct ext2_group_desc
*) dest
;
434 for (j
=0; j
< groups_per_block
*first_meta_bg
; j
++) {
435 gdp
= ext2fs_group_desc(fs
, fs
->group_desc
, j
);
436 ext2fs_swap_group_desc2(fs
, gdp
);
439 dest
+= fs
->blocksize
*first_meta_bg
;
442 for (i
= first_meta_bg
; i
< fs
->desc_blocks
; i
++) {
443 blk
= ext2fs_descriptor_block_loc2(fs
, group_block
, i
);
444 io_channel_cache_readahead(fs
->io
, blk
, 1);
447 for (i
=first_meta_bg
; i
< fs
->desc_blocks
; i
++) {
448 blk
= ext2fs_descriptor_block_loc2(fs
, group_block
, i
);
449 retval
= io_channel_read_blk64(fs
->io
, blk
, 1, dest
);
452 #ifdef WORDS_BIGENDIAN
453 for (j
=0; j
< groups_per_block
; j
++) {
454 gdp
= ext2fs_group_desc(fs
, fs
->group_desc
,
455 i
* groups_per_block
+ j
);
456 ext2fs_swap_group_desc2(fs
, gdp
);
459 dest
+= fs
->blocksize
;
462 fs
->stride
= fs
->super
->s_raid_stride
;
465 * If recovery is from backup superblock, Clear _UNININT flags &
466 * reset bg_itable_unused to zero
468 if (superblock
> 1 && ext2fs_has_group_desc_csum(fs
)) {
471 for (group
= 0; group
< fs
->group_desc_count
; group
++) {
472 ext2fs_bg_flags_clear(fs
, group
, EXT2_BG_BLOCK_UNINIT
);
473 ext2fs_bg_flags_clear(fs
, group
, EXT2_BG_INODE_UNINIT
);
474 ext2fs_bg_itable_unused_set(fs
, group
, 0);
475 /* The checksum will be reset later, but fix it here
476 * anyway to avoid printing a lot of spurious errors. */
477 ext2fs_group_desc_csum_set(fs
, group
);
479 if (fs
->flags
& EXT2_FLAG_RW
)
480 ext2fs_mark_super_dirty(fs
);
483 if (ext2fs_has_feature_mmp(fs
->super
) &&
484 !(flags
& EXT2_FLAG_SKIP_MMP
) &&
485 (flags
& (EXT2_FLAG_RW
| EXT2_FLAG_EXCLUSIVE
))) {
486 retval
= ext2fs_mmp_start(fs
);
488 fs
->flags
|= EXT2_FLAG_SKIP_MMP
; /* just do cleanup */
494 if (fs
->flags
& EXT2_FLAG_SHARE_DUP
) {
495 fs
->block_sha_map
= ext2fs_hashmap_create(ext2fs_djb2_hash
,
496 block_sha_map_free_entry
, 4096);
497 if (!fs
->block_sha_map
) {
498 retval
= EXT2_ET_NO_MEMORY
;
501 ext2fs_set_feature_shared_blocks(fs
->super
);
504 if (ext2fs_has_feature_casefold(fs
->super
))
505 fs
->encoding
= ext2fs_load_nls_table(fs
->super
->s_encoding
);
507 fs
->flags
&= ~EXT2_FLAG_NOFREE_ON_ERROR
;
512 if (!(flags
& EXT2_FLAG_NOFREE_ON_ERROR
)) {
521 * Set/get the filesystem data I/O channel.
523 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
525 errcode_t
ext2fs_get_data_io(ext2_filsys fs
, io_channel
*old_io
)
527 if ((fs
->flags
& EXT2_FLAG_IMAGE_FILE
) == 0)
528 return EXT2_ET_NOT_IMAGE_FILE
;
530 *old_io
= (fs
->image_io
== fs
->io
) ? 0 : fs
->io
;
535 errcode_t
ext2fs_set_data_io(ext2_filsys fs
, io_channel new_io
)
537 if ((fs
->flags
& EXT2_FLAG_IMAGE_FILE
) == 0)
538 return EXT2_ET_NOT_IMAGE_FILE
;
539 fs
->io
= new_io
? new_io
: fs
->image_io
;
543 errcode_t
ext2fs_rewrite_to_io(ext2_filsys fs
, io_channel new_io
)
547 if ((fs
->flags
& EXT2_FLAG_IMAGE_FILE
) == 0)
548 return EXT2_ET_NOT_IMAGE_FILE
;
549 err
= io_channel_set_blksize(new_io
, fs
->blocksize
);
552 if ((new_io
== fs
->image_io
) || (new_io
== fs
->io
))
554 if ((fs
->image_io
!= fs
->io
) &&
556 io_channel_close(fs
->image_io
);
558 io_channel_close(fs
->io
);
559 fs
->io
= fs
->image_io
= new_io
;
560 fs
->flags
|= EXT2_FLAG_DIRTY
| EXT2_FLAG_RW
|
561 EXT2_FLAG_BB_DIRTY
| EXT2_FLAG_IB_DIRTY
;
562 fs
->flags
&= ~EXT2_FLAG_IMAGE_FILE
;