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 (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
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;
124 #ifdef WORDS_BIGENDIAN
125 unsigned int groups_per_block;
126 struct ext2_group_desc *gdp;
130 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
132 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
136 memset(fs, 0, sizeof(struct struct_ext2_filsys));
137 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
139 /* don't overwrite sb backups unless flag is explicitly cleared */
140 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
142 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
145 strcpy(fs->device_name, name);
146 cp = strchr(fs->device_name, '?');
147 if (!io_options && cp) {
153 if (flags & EXT2_FLAG_RW)
154 io_flags |= IO_FLAG_RW;
155 if (flags & EXT2_FLAG_EXCLUSIVE)
156 io_flags |= IO_FLAG_EXCLUSIVE;
157 if (flags & EXT2_FLAG_DIRECT_IO)
158 io_flags |= IO_FLAG_DIRECT_IO;
159 retval = manager->open(fs->device_name, io_flags, &fs->io);
163 (retval = io_channel_set_options(fs->io, io_options)))
165 fs->image_io = fs->io;
166 fs->io->app_data = fs;
167 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
170 if (flags & EXT2_FLAG_IMAGE_FILE) {
171 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
175 retval = io_channel_read_blk(fs->io, 0,
176 -(int)sizeof(struct ext2_image_hdr),
180 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
181 return EXT2_ET_MAGIC_E2IMAGE;
183 block_size = fs->image_header->fs_blocksize;
187 * If the user specifies a specific block # for the
188 * superblock, then he/she must also specify the block size!
189 * Otherwise, read the master superblock located at offset
190 * SUPERBLOCK_OFFSET from the start of the partition.
192 * Note: we only save a backup copy of the superblock if we
193 * are reading the superblock from the primary superblock location.
197 retval = EXT2_ET_INVALID_ARGUMENT;
200 io_channel_set_blksize(fs->io, block_size);
201 group_block = superblock;
204 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
207 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
211 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
216 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
218 #ifdef WORDS_BIGENDIAN
219 fs->flags |= EXT2_FLAG_SWAP_BYTES;
220 ext2fs_swap_super(fs->super);
222 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
223 retval = EXT2_ET_UNIMPLEMENTED;
228 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
229 retval = EXT2_ET_BAD_MAGIC;
232 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
233 retval = EXT2_ET_REV_TOO_HIGH;
238 * Check for feature set incompatibility
240 if (!(flags & EXT2_FLAG_FORCE)) {
241 features = fs->super->s_feature_incompat;
242 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
243 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
244 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
246 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
247 retval = EXT2_ET_UNSUPP_FEATURE;
251 features = fs->super->s_feature_ro_compat;
252 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
253 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
254 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
256 if ((flags & EXT2_FLAG_RW) &&
257 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
258 retval = EXT2_ET_RO_UNSUPP_FEATURE;
262 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
263 (fs->super->s_feature_incompat &
264 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
265 retval = EXT2_ET_UNSUPP_FEATURE;
270 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
271 EXT2_MAX_BLOCK_LOG_SIZE) {
272 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
277 * bigalloc requires cluster-aware bitfield operations, which at the
278 * moment means we need EXT2_FLAG_64BITS.
280 if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
281 EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
282 !(flags & EXT2_FLAG_64BITS)) {
283 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
287 if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
288 EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
289 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
290 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
293 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
294 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
295 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
298 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
299 fs->super->s_log_block_size;
300 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
301 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
302 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
305 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
306 EXT2_INODE_SIZE(fs->super) +
307 EXT2_BLOCK_SIZE(fs->super) - 1) /
308 EXT2_BLOCK_SIZE(fs->super));
310 if (block_size != fs->blocksize) {
311 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
316 * Set the blocksize to the filesystem's blocksize.
318 io_channel_set_blksize(fs->io, fs->blocksize);
321 * If this is an external journal device, don't try to read
322 * the group descriptors, because they're not there.
324 if (fs->super->s_feature_incompat &
325 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
326 fs->group_desc_count = 0;
331 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
332 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
337 * Read group descriptors
339 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
340 if (blocks_per_group == 0 ||
341 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
342 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
343 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
344 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
345 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
348 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
349 fs->super->s_first_data_block,
351 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
352 fs->super->s_inodes_count) {
353 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
356 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
357 EXT2_DESC_PER_BLOCK(fs->super));
358 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
363 group_block = fs->super->s_first_data_block;
365 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
366 * so we must increment block numbers to any group 0 items.
368 * However, we cannot touch group_block directly because in the meta_bg
369 * case, the ext2fs_descriptor_block_loc2() function will interpret
370 * group_block != s_first_data_block to mean that we want to access the
371 * backup group descriptors. This is not what we want if the caller
372 * set superblock == 0 (i.e. auto-detect the superblock), which is
373 * what's going on here.
375 if (group_block == 0 && fs->blocksize == 1024)
376 group_zero_adjust = 1;
377 dest = (char *) fs->group_desc;
378 #ifdef WORDS_BIGENDIAN
379 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
381 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) {
382 first_meta_bg = fs->super->s_first_meta_bg;
383 if (first_meta_bg > fs->desc_blocks)
384 first_meta_bg = fs->desc_blocks;
386 first_meta_bg = fs->desc_blocks;
388 retval = io_channel_read_blk(fs->io, group_block +
389 group_zero_adjust + 1,
390 first_meta_bg, dest);
393 #ifdef WORDS_BIGENDIAN
394 gdp = (struct ext2_group_desc *) dest;
395 for (j=0; j < groups_per_block*first_meta_bg; j++) {
396 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
397 ext2fs_swap_group_desc2(fs, gdp);
400 dest += fs->blocksize*first_meta_bg;
402 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
403 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
404 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
407 #ifdef WORDS_BIGENDIAN
408 for (j=0; j < groups_per_block; j++) {
409 gdp = ext2fs_group_desc(fs, fs->group_desc,
410 i * groups_per_block + j);
411 ext2fs_swap_group_desc2(fs, gdp);
414 dest += fs->blocksize;
417 fs->stride = fs->super->s_raid_stride;
420 * If recovery is from backup superblock, Clear _UNININT flags &
421 * reset bg_itable_unused to zero
423 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
424 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
427 for (group = 0; group < fs->group_desc_count; group++) {
428 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
429 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
430 ext2fs_bg_itable_unused_set(fs, group, 0);
431 /* The checksum will be reset later, but fix it here
432 * anyway to avoid printing a lot of spurious errors. */
433 ext2fs_group_desc_csum_set(fs, group);
435 if (fs->flags & EXT2_FLAG_RW)
436 ext2fs_mark_super_dirty(fs);
439 if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) &&
440 !(flags & EXT2_FLAG_SKIP_MMP) &&
441 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
442 retval = ext2fs_mmp_start(fs);
444 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
450 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
455 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
464 * Set/get the filesystem data I/O channel.
466 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
468 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
470 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
471 return EXT2_ET_NOT_IMAGE_FILE;
473 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
478 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
480 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
481 return EXT2_ET_NOT_IMAGE_FILE;
482 fs->io = new_io ? new_io : fs->image_io;
486 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
490 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
491 return EXT2_ET_NOT_IMAGE_FILE;
492 err = io_channel_set_blksize(new_io, fs->blocksize);
495 if ((new_io == fs->image_io) || (new_io == fs->io))
497 if ((fs->image_io != fs->io) &&
499 io_channel_close(fs->image_io);
501 io_channel_close(fs->io);
502 fs->io = fs->image_io = new_io;
503 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
504 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
505 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;