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,
43 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
44 (i < fs->super->s_first_meta_bg))
45 return (group_block + i + 1);
47 bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
48 if (ext2fs_bg_has_super(fs, bg))
50 ret_blk = ext2fs_group_first_block2(fs, bg) + has_super;
52 * If group_block is not the normal value, we're trying to use
53 * the backup group descriptors and superblock --- so use the
54 * alternate location of the second block group in the
55 * metablock group. Ideally we should be testing each bg
56 * descriptor block individually for correctness, but we don't
57 * have the infrastructure in place to do that.
59 if (group_block != fs->super->s_first_data_block &&
60 ((ret_blk + fs->super->s_blocks_per_group) <
61 ext2fs_blocks_count(fs->super)))
62 ret_blk += fs->super->s_blocks_per_group;
66 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
68 return ext2fs_descriptor_block_loc2(fs, group_block, i);
71 errcode_t ext2fs_open(const char *name, int flags, int superblock,
72 unsigned int block_size, io_manager manager,
75 return ext2fs_open2(name, 0, flags, superblock, block_size,
80 * Note: if superblock is non-zero, block-size must also be non-zero.
81 * Superblock and block_size can be zero to use the default size.
83 * Valid flags for ext2fs_open()
85 * EXT2_FLAG_RW - Open the filesystem for read/write.
86 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
87 * features aren't supported.
88 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
89 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
90 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
93 errcode_t ext2fs_open2(const char *name, const char *io_options,
94 int flags, int superblock,
95 unsigned int block_size, io_manager manager,
100 unsigned long i, first_meta_bg;
102 unsigned int groups_per_block, blocks_per_group, io_flags;
103 blk64_t group_block, blk;
105 #ifdef WORDS_BIGENDIAN
106 struct ext2_group_desc *gdp;
110 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
112 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
116 memset(fs, 0, sizeof(struct struct_ext2_filsys));
117 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
119 /* don't overwrite sb backups unless flag is explicitly cleared */
120 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
122 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
125 strcpy(fs->device_name, name);
126 cp = strchr(fs->device_name, '?');
127 if (!io_options && cp) {
133 if (flags & EXT2_FLAG_RW)
134 io_flags |= IO_FLAG_RW;
135 if (flags & EXT2_FLAG_EXCLUSIVE)
136 io_flags |= IO_FLAG_EXCLUSIVE;
137 if (flags & EXT2_FLAG_DIRECT_IO)
138 io_flags |= IO_FLAG_DIRECT_IO;
139 retval = manager->open(fs->device_name, io_flags, &fs->io);
143 (retval = io_channel_set_options(fs->io, io_options)))
145 fs->image_io = fs->io;
146 fs->io->app_data = fs;
147 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
150 if (flags & EXT2_FLAG_IMAGE_FILE) {
151 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
155 retval = io_channel_read_blk(fs->io, 0,
156 -(int)sizeof(struct ext2_image_hdr),
160 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
161 return EXT2_ET_MAGIC_E2IMAGE;
163 block_size = fs->image_header->fs_blocksize;
167 * If the user specifies a specific block # for the
168 * superblock, then he/she must also specify the block size!
169 * Otherwise, read the master superblock located at offset
170 * SUPERBLOCK_OFFSET from the start of the partition.
172 * Note: we only save a backup copy of the superblock if we
173 * are reading the superblock from the primary superblock location.
177 retval = EXT2_ET_INVALID_ARGUMENT;
180 io_channel_set_blksize(fs->io, block_size);
181 group_block = superblock;
184 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
187 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
191 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
196 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
198 #ifdef WORDS_BIGENDIAN
199 fs->flags |= EXT2_FLAG_SWAP_BYTES;
200 ext2fs_swap_super(fs->super);
202 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
203 retval = EXT2_ET_UNIMPLEMENTED;
208 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
209 retval = EXT2_ET_BAD_MAGIC;
212 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
213 retval = EXT2_ET_REV_TOO_HIGH;
218 * Check for feature set incompatibility
220 if (!(flags & EXT2_FLAG_FORCE)) {
221 features = fs->super->s_feature_incompat;
222 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
223 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
224 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
226 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
227 retval = EXT2_ET_UNSUPP_FEATURE;
231 features = fs->super->s_feature_ro_compat;
232 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
233 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
234 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
236 if ((flags & EXT2_FLAG_RW) &&
237 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
238 retval = EXT2_ET_RO_UNSUPP_FEATURE;
242 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
243 (fs->super->s_feature_incompat &
244 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
245 retval = EXT2_ET_UNSUPP_FEATURE;
250 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
251 EXT2_MAX_BLOCK_LOG_SIZE) {
252 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
255 if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
256 EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
257 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
258 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
261 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
262 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
263 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
267 /* Enforce the block group descriptor size */
268 if (fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) {
269 if (fs->super->s_desc_size != EXT2_MIN_DESC_SIZE_64BIT) {
270 retval = EXT2_ET_BAD_DESC_SIZE;
274 if (fs->super->s_desc_size &&
275 fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) {
276 retval = EXT2_ET_BAD_DESC_SIZE;
281 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
282 fs->super->s_log_block_size;
283 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
284 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
285 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
288 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
289 EXT2_INODE_SIZE(fs->super) +
290 EXT2_BLOCK_SIZE(fs->super) - 1) /
291 EXT2_BLOCK_SIZE(fs->super));
293 if (block_size != fs->blocksize) {
294 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
299 * Set the blocksize to the filesystem's blocksize.
301 io_channel_set_blksize(fs->io, fs->blocksize);
304 * If this is an external journal device, don't try to read
305 * the group descriptors, because they're not there.
307 if (fs->super->s_feature_incompat &
308 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
309 fs->group_desc_count = 0;
314 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
315 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
318 /* Precompute the FS UUID to seed other checksums */
319 ext2fs_init_csum_seed(fs);
322 * Read group descriptors
324 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
325 if (blocks_per_group == 0 ||
326 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
327 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
328 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
329 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
330 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
333 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
334 fs->super->s_first_data_block,
336 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
337 fs->super->s_inodes_count) {
338 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
341 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
342 EXT2_DESC_PER_BLOCK(fs->super));
343 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
348 group_block = fs->super->s_first_data_block;
349 if (group_block == 0 && fs->blocksize == 1024)
350 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
351 dest = (char *) fs->group_desc;
352 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
353 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
354 first_meta_bg = fs->super->s_first_meta_bg;
356 first_meta_bg = fs->desc_blocks;
358 retval = io_channel_read_blk(fs->io, group_block+1,
359 first_meta_bg, dest);
362 #ifdef WORDS_BIGENDIAN
363 gdp = (struct ext2_group_desc *) dest;
364 for (j=0; j < groups_per_block*first_meta_bg; j++) {
365 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
366 ext2fs_swap_group_desc2(fs, gdp);
369 dest += fs->blocksize*first_meta_bg;
371 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
372 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
373 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
376 #ifdef WORDS_BIGENDIAN
377 for (j=0; j < groups_per_block; j++) {
378 gdp = ext2fs_group_desc(fs, fs->group_desc,
379 i * groups_per_block + j);
380 ext2fs_swap_group_desc2(fs, gdp);
383 dest += fs->blocksize;
386 fs->stride = fs->super->s_raid_stride;
389 * If recovery is from backup superblock, Clear _UNININT flags &
390 * reset bg_itable_unused to zero
392 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
393 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
396 for (group = 0; group < fs->group_desc_count; group++) {
397 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
398 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
399 ext2fs_bg_itable_unused_set(fs, group, 0);
400 /* The checksum will be reset later, but fix it here
401 * anyway to avoid printing a lot of spurious errors. */
402 ext2fs_group_desc_csum_set(fs, group);
404 if (fs->flags & EXT2_FLAG_RW)
405 ext2fs_mark_super_dirty(fs);
408 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
411 if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) &&
412 !(flags & EXT2_FLAG_SKIP_MMP) &&
413 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
414 retval = ext2fs_mmp_start(fs);
416 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
424 if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
432 * Set/get the filesystem data I/O channel.
434 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
436 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
438 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
439 return EXT2_ET_NOT_IMAGE_FILE;
441 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
446 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
448 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
449 return EXT2_ET_NOT_IMAGE_FILE;
450 fs->io = new_io ? new_io : fs->image_io;
454 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
456 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
457 return EXT2_ET_NOT_IMAGE_FILE;
458 fs->io = fs->image_io = new_io;
459 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
460 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
461 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;