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>
36 blk64_t
ext2fs_descriptor_block_loc2(ext2_filsys fs
, blk64_t group_block
,
40 int has_super
= 0, group_zero_adjust
= 0;
44 * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4
45 * stuff, so adjust for that if we're being asked for group 0.
47 if (i
== 0 && fs
->blocksize
== 1024 && EXT2FS_CLUSTER_RATIO(fs
) > 1)
48 group_zero_adjust
= 1;
50 if (!ext2fs_has_feature_meta_bg(fs
->super
) ||
51 (i
< fs
->super
->s_first_meta_bg
))
52 return group_block
+ i
+ 1 + group_zero_adjust
;
54 bg
= EXT2_DESC_PER_BLOCK(fs
->super
) * i
;
55 if (ext2fs_bg_has_super(fs
, bg
))
57 ret_blk
= ext2fs_group_first_block2(fs
, bg
);
59 * If group_block is not the normal value, we're trying to use
60 * the backup group descriptors and superblock --- so use the
61 * alternate location of the second block group in the
62 * metablock group. Ideally we should be testing each bg
63 * descriptor block individually for correctness, but we don't
64 * have the infrastructure in place to do that.
66 if (group_block
!= fs
->super
->s_first_data_block
&&
67 ((ret_blk
+ has_super
+ fs
->super
->s_blocks_per_group
) <
68 ext2fs_blocks_count(fs
->super
))) {
69 ret_blk
+= fs
->super
->s_blocks_per_group
;
72 * If we're going to jump forward a block group, make sure
73 * that we adjust has_super to account for the next group's
74 * backup superblock (or lack thereof).
76 if (ext2fs_bg_has_super(fs
, bg
+ 1))
81 return ret_blk
+ has_super
+ group_zero_adjust
;
84 blk_t
ext2fs_descriptor_block_loc(ext2_filsys fs
, blk_t group_block
, dgrp_t i
)
86 return ext2fs_descriptor_block_loc2(fs
, group_block
, i
);
89 errcode_t
ext2fs_open(const char *name
, int flags
, int superblock
,
90 unsigned int block_size
, io_manager manager
,
93 return ext2fs_open2(name
, 0, flags
, superblock
, block_size
,
98 * Note: if superblock is non-zero, block-size must also be non-zero.
99 * Superblock and block_size can be zero to use the default size.
101 * Valid flags for ext2fs_open()
103 * EXT2_FLAG_RW - Open the filesystem for read/write.
104 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
105 * features aren't supported.
106 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
107 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
108 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
111 errcode_t
ext2fs_open2(const char *name
, const char *io_options
,
112 int flags
, int superblock
,
113 unsigned int block_size
, io_manager manager
,
118 unsigned long i
, first_meta_bg
;
120 unsigned int blocks_per_group
, io_flags
;
121 blk64_t group_block
, blk
;
123 int group_zero_adjust
= 0;
126 #ifdef WORDS_BIGENDIAN
127 unsigned int groups_per_block
;
128 struct ext2_group_desc
*gdp
;
133 EXT2_CHECK_MAGIC(manager
, EXT2_ET_MAGIC_IO_MANAGER
);
135 retval
= ext2fs_get_mem(sizeof(struct struct_ext2_filsys
), &fs
);
139 memset(fs
, 0, sizeof(struct struct_ext2_filsys
));
140 fs
->magic
= EXT2_ET_MAGIC_EXT2FS_FILSYS
;
142 /* don't overwrite sb backups unless flag is explicitly cleared */
143 fs
->flags
|= EXT2_FLAG_MASTER_SB_ONLY
;
146 time_env
= getenv("E2FSPROGS_FAKE_TIME");
148 fs
->now
= strtoul(time_env
, NULL
, 0);
150 retval
= ext2fs_get_mem(strlen(name
)+1, &fs
->device_name
);
153 strcpy(fs
->device_name
, name
);
154 cp
= strchr(fs
->device_name
, '?');
155 if (!io_options
&& cp
) {
161 if (flags
& EXT2_FLAG_RW
)
162 io_flags
|= IO_FLAG_RW
;
163 if (flags
& EXT2_FLAG_EXCLUSIVE
)
164 io_flags
|= IO_FLAG_EXCLUSIVE
;
165 if (flags
& EXT2_FLAG_DIRECT_IO
)
166 io_flags
|= IO_FLAG_DIRECT_IO
;
167 retval
= manager
->open(fs
->device_name
, io_flags
, &fs
->io
);
171 (retval
= io_channel_set_options(fs
->io
, io_options
)))
173 fs
->image_io
= fs
->io
;
174 fs
->io
->app_data
= fs
;
175 retval
= io_channel_alloc_buf(fs
->io
, -SUPERBLOCK_SIZE
, &fs
->super
);
178 if (flags
& EXT2_FLAG_IMAGE_FILE
) {
179 retval
= ext2fs_get_mem(sizeof(struct ext2_image_hdr
),
183 retval
= io_channel_read_blk(fs
->io
, 0,
184 -(int)sizeof(struct ext2_image_hdr
),
188 if (ext2fs_le32_to_cpu(fs
->image_header
->magic_number
) != EXT2_ET_MAGIC_E2IMAGE
)
189 return EXT2_ET_MAGIC_E2IMAGE
;
191 block_size
= ext2fs_le32_to_cpu(fs
->image_header
->fs_blocksize
);
195 * If the user specifies a specific block # for the
196 * superblock, then he/she must also specify the block size!
197 * Otherwise, read the master superblock located at offset
198 * SUPERBLOCK_OFFSET from the start of the partition.
200 * Note: we only save a backup copy of the superblock if we
201 * are reading the superblock from the primary superblock location.
205 retval
= EXT2_ET_INVALID_ARGUMENT
;
208 io_channel_set_blksize(fs
->io
, block_size
);
209 group_block
= superblock
;
212 io_channel_set_blksize(fs
->io
, SUPERBLOCK_OFFSET
);
215 retval
= ext2fs_get_mem(SUPERBLOCK_SIZE
, &fs
->orig_super
);
219 retval
= io_channel_read_blk(fs
->io
, superblock
, -SUPERBLOCK_SIZE
,
224 memcpy(fs
->orig_super
, fs
->super
, SUPERBLOCK_SIZE
);
226 if (!(fs
->flags
& EXT2_FLAG_IGNORE_CSUM_ERRORS
)) {
228 if (!ext2fs_verify_csum_type(fs
, fs
->super
))
229 retval
= EXT2_ET_UNKNOWN_CSUM
;
230 if (!ext2fs_superblock_csum_verify(fs
, fs
->super
))
231 retval
= EXT2_ET_SB_CSUM_INVALID
;
234 #ifdef WORDS_BIGENDIAN
235 fs
->flags
|= EXT2_FLAG_SWAP_BYTES
;
236 ext2fs_swap_super(fs
->super
);
238 if (fs
->flags
& EXT2_FLAG_SWAP_BYTES
) {
239 retval
= EXT2_ET_UNIMPLEMENTED
;
244 if (fs
->super
->s_magic
!= EXT2_SUPER_MAGIC
)
245 retval
= EXT2_ET_BAD_MAGIC
;
249 if (fs
->super
->s_rev_level
> EXT2_LIB_CURRENT_REV
) {
250 retval
= EXT2_ET_REV_TOO_HIGH
;
255 * Check for feature set incompatibility
257 if (!(flags
& EXT2_FLAG_FORCE
)) {
258 features
= fs
->super
->s_feature_incompat
;
259 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
260 if (flags
& EXT2_FLAG_SOFTSUPP_FEATURES
)
261 features
&= ~EXT2_LIB_SOFTSUPP_INCOMPAT
;
263 if (features
& ~EXT2_LIB_FEATURE_INCOMPAT_SUPP
) {
264 retval
= EXT2_ET_UNSUPP_FEATURE
;
268 features
= fs
->super
->s_feature_ro_compat
;
269 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
270 if (flags
& EXT2_FLAG_SOFTSUPP_FEATURES
)
271 features
&= ~EXT2_LIB_SOFTSUPP_RO_COMPAT
;
273 if ((flags
& EXT2_FLAG_RW
) &&
274 (features
& ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP
)) {
275 retval
= EXT2_ET_RO_UNSUPP_FEATURE
;
279 if (!(flags
& EXT2_FLAG_JOURNAL_DEV_OK
) &&
280 ext2fs_has_feature_journal_dev(fs
->super
)) {
281 retval
= EXT2_ET_UNSUPP_FEATURE
;
286 if (fs
->super
->s_log_block_size
>
287 (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE
- EXT2_MIN_BLOCK_LOG_SIZE
)) {
288 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
293 * bigalloc requires cluster-aware bitfield operations, which at the
294 * moment means we need EXT2_FLAG_64BITS.
296 if (ext2fs_has_feature_bigalloc(fs
->super
) &&
297 !(flags
& EXT2_FLAG_64BITS
)) {
298 retval
= EXT2_ET_CANT_USE_LEGACY_BITMAPS
;
302 if (!ext2fs_has_feature_bigalloc(fs
->super
) &&
303 (fs
->super
->s_log_block_size
!= fs
->super
->s_log_cluster_size
)) {
304 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
307 fs
->fragsize
= fs
->blocksize
= EXT2_BLOCK_SIZE(fs
->super
);
308 inode_size
= EXT2_INODE_SIZE(fs
->super
);
309 if ((inode_size
< EXT2_GOOD_OLD_INODE_SIZE
) ||
310 (inode_size
> fs
->blocksize
) ||
311 (inode_size
& (inode_size
- 1))) {
312 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
316 /* Enforce the block group descriptor size */
317 if (ext2fs_has_feature_64bit(fs
->super
)) {
318 if (fs
->super
->s_desc_size
< EXT2_MIN_DESC_SIZE_64BIT
) {
319 retval
= EXT2_ET_BAD_DESC_SIZE
;
324 fs
->cluster_ratio_bits
= fs
->super
->s_log_cluster_size
-
325 fs
->super
->s_log_block_size
;
326 if (EXT2_BLOCKS_PER_GROUP(fs
->super
) !=
327 EXT2_CLUSTERS_PER_GROUP(fs
->super
) << fs
->cluster_ratio_bits
) {
328 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
331 fs
->inode_blocks_per_group
= ((EXT2_INODES_PER_GROUP(fs
->super
) *
332 EXT2_INODE_SIZE(fs
->super
) +
333 EXT2_BLOCK_SIZE(fs
->super
) - 1) /
334 EXT2_BLOCK_SIZE(fs
->super
));
336 if (block_size
!= fs
->blocksize
) {
337 retval
= EXT2_ET_UNEXPECTED_BLOCK_SIZE
;
342 * Set the blocksize to the filesystem's blocksize.
344 io_channel_set_blksize(fs
->io
, fs
->blocksize
);
347 * If this is an external journal device, don't try to read
348 * the group descriptors, because they're not there.
350 if (ext2fs_has_feature_journal_dev(fs
->super
)) {
351 fs
->group_desc_count
= 0;
356 if (EXT2_INODES_PER_GROUP(fs
->super
) == 0) {
357 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
360 /* Precompute the FS UUID to seed other checksums */
361 ext2fs_init_csum_seed(fs
);
364 * Read group descriptors
366 blocks_per_group
= EXT2_BLOCKS_PER_GROUP(fs
->super
);
367 if (blocks_per_group
== 0 ||
368 blocks_per_group
> EXT2_MAX_BLOCKS_PER_GROUP(fs
->super
) ||
369 fs
->inode_blocks_per_group
> EXT2_MAX_INODES_PER_GROUP(fs
->super
) ||
370 EXT2_DESC_PER_BLOCK(fs
->super
) == 0 ||
371 fs
->super
->s_first_data_block
>= ext2fs_blocks_count(fs
->super
)) {
372 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
375 groups_cnt
= ext2fs_div64_ceil(ext2fs_blocks_count(fs
->super
) -
376 fs
->super
->s_first_data_block
,
378 if (groups_cnt
>> 32) {
379 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
382 fs
->group_desc_count
= groups_cnt
;
383 if (!(flags
& EXT2_FLAG_IGNORE_SB_ERRORS
) &&
384 (__u64
)fs
->group_desc_count
* EXT2_INODES_PER_GROUP(fs
->super
) !=
385 fs
->super
->s_inodes_count
) {
386 retval
= EXT2_ET_CORRUPT_SUPERBLOCK
;
389 fs
->desc_blocks
= ext2fs_div_ceil(fs
->group_desc_count
,
390 EXT2_DESC_PER_BLOCK(fs
->super
));
391 retval
= ext2fs_get_array(fs
->desc_blocks
, fs
->blocksize
,
396 group_block
= fs
->super
->s_first_data_block
;
398 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
399 * so we must increment block numbers to any group 0 items.
401 * However, we cannot touch group_block directly because in the meta_bg
402 * case, the ext2fs_descriptor_block_loc2() function will interpret
403 * group_block != s_first_data_block to mean that we want to access the
404 * backup group descriptors. This is not what we want if the caller
405 * set superblock == 0 (i.e. auto-detect the superblock), which is
406 * what's going on here.
408 if (group_block
== 0 && fs
->blocksize
== 1024)
409 group_zero_adjust
= 1;
410 dest
= (char *) fs
->group_desc
;
411 #ifdef WORDS_BIGENDIAN
412 groups_per_block
= EXT2_DESC_PER_BLOCK(fs
->super
);
414 if (ext2fs_has_feature_meta_bg(fs
->super
) &&
415 !(flags
& EXT2_FLAG_IMAGE_FILE
)) {
416 first_meta_bg
= fs
->super
->s_first_meta_bg
;
417 if (first_meta_bg
> fs
->desc_blocks
)
418 first_meta_bg
= fs
->desc_blocks
;
420 first_meta_bg
= fs
->desc_blocks
;
422 retval
= io_channel_read_blk(fs
->io
, group_block
+
423 group_zero_adjust
+ 1,
424 first_meta_bg
, dest
);
427 #ifdef WORDS_BIGENDIAN
428 gdp
= (struct ext2_group_desc
*) dest
;
429 for (j
=0; j
< groups_per_block
*first_meta_bg
; j
++) {
430 gdp
= ext2fs_group_desc(fs
, fs
->group_desc
, j
);
431 ext2fs_swap_group_desc2(fs
, gdp
);
434 dest
+= fs
->blocksize
*first_meta_bg
;
437 for (i
= first_meta_bg
; i
< fs
->desc_blocks
; i
++) {
438 blk
= ext2fs_descriptor_block_loc2(fs
, group_block
, i
);
439 io_channel_cache_readahead(fs
->io
, blk
, 1);
442 for (i
=first_meta_bg
; i
< fs
->desc_blocks
; i
++) {
443 blk
= ext2fs_descriptor_block_loc2(fs
, group_block
, i
);
444 retval
= io_channel_read_blk64(fs
->io
, blk
, 1, dest
);
447 #ifdef WORDS_BIGENDIAN
448 for (j
=0; j
< groups_per_block
; j
++) {
449 gdp
= ext2fs_group_desc(fs
, fs
->group_desc
,
450 i
* groups_per_block
+ j
);
451 ext2fs_swap_group_desc2(fs
, gdp
);
454 dest
+= fs
->blocksize
;
457 fs
->stride
= fs
->super
->s_raid_stride
;
460 * If recovery is from backup superblock, Clear _UNININT flags &
461 * reset bg_itable_unused to zero
463 if (superblock
> 1 && ext2fs_has_group_desc_csum(fs
)) {
466 for (group
= 0; group
< fs
->group_desc_count
; group
++) {
467 ext2fs_bg_flags_clear(fs
, group
, EXT2_BG_BLOCK_UNINIT
);
468 ext2fs_bg_flags_clear(fs
, group
, EXT2_BG_INODE_UNINIT
);
469 ext2fs_bg_itable_unused_set(fs
, group
, 0);
470 /* The checksum will be reset later, but fix it here
471 * anyway to avoid printing a lot of spurious errors. */
472 ext2fs_group_desc_csum_set(fs
, group
);
474 if (fs
->flags
& EXT2_FLAG_RW
)
475 ext2fs_mark_super_dirty(fs
);
478 if (ext2fs_has_feature_mmp(fs
->super
) &&
479 !(flags
& EXT2_FLAG_SKIP_MMP
) &&
480 (flags
& (EXT2_FLAG_RW
| EXT2_FLAG_EXCLUSIVE
))) {
481 retval
= ext2fs_mmp_start(fs
);
483 fs
->flags
|= EXT2_FLAG_SKIP_MMP
; /* just do cleanup */
489 fs
->flags
&= ~EXT2_FLAG_NOFREE_ON_ERROR
;
494 if (!(flags
& EXT2_FLAG_NOFREE_ON_ERROR
)) {
503 * Set/get the filesystem data I/O channel.
505 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
507 errcode_t
ext2fs_get_data_io(ext2_filsys fs
, io_channel
*old_io
)
509 if ((fs
->flags
& EXT2_FLAG_IMAGE_FILE
) == 0)
510 return EXT2_ET_NOT_IMAGE_FILE
;
512 *old_io
= (fs
->image_io
== fs
->io
) ? 0 : fs
->io
;
517 errcode_t
ext2fs_set_data_io(ext2_filsys fs
, io_channel new_io
)
519 if ((fs
->flags
& EXT2_FLAG_IMAGE_FILE
) == 0)
520 return EXT2_ET_NOT_IMAGE_FILE
;
521 fs
->io
= new_io
? new_io
: fs
->image_io
;
525 errcode_t
ext2fs_rewrite_to_io(ext2_filsys fs
, io_channel new_io
)
529 if ((fs
->flags
& EXT2_FLAG_IMAGE_FILE
) == 0)
530 return EXT2_ET_NOT_IMAGE_FILE
;
531 err
= io_channel_set_blksize(new_io
, fs
->blocksize
);
534 if ((new_io
== fs
->image_io
) || (new_io
== fs
->io
))
536 if ((fs
->image_io
!= fs
->io
) &&
538 io_channel_close(fs
->image_io
);
540 io_channel_close(fs
->io
);
541 fs
->io
= fs
->image_io
= new_io
;
542 fs
->flags
|= EXT2_FLAG_DIRTY
| EXT2_FLAG_RW
|
543 EXT2_FLAG_BB_DIRTY
| EXT2_FLAG_IB_DIRTY
;
544 fs
->flags
&= ~EXT2_FLAG_IMAGE_FILE
;