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 Public
23 #include <sys/types.h>
32 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block,
39 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
40 (i < fs->super->s_first_meta_bg))
41 return (group_block + i + 1);
43 bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
44 if (ext2fs_bg_has_super(fs, bg))
46 ret_blk = ext2fs_group_first_block2(fs, bg) + has_super;
48 * If group_block is not the normal value, we're trying to use
49 * the backup group descriptors and superblock --- so use the
50 * alternate location of the second block group in the
51 * metablock group. Ideally we should be testing each bg
52 * descriptor block individually for correctness, but we don't
53 * have the infrastructure in place to do that.
55 if (group_block != fs->super->s_first_data_block &&
56 ((ret_blk + fs->super->s_blocks_per_group) <
57 ext2fs_blocks_count(fs->super)))
58 ret_blk += fs->super->s_blocks_per_group;
62 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
64 return ext2fs_descriptor_block_loc2(fs, group_block, i);
67 errcode_t ext2fs_open(const char *name, int flags, int superblock,
68 unsigned int block_size, io_manager manager,
71 return ext2fs_open2(name, 0, flags, superblock, block_size,
76 * Note: if superblock is non-zero, block-size must also be non-zero.
77 * Superblock and block_size can be zero to use the default size.
79 * Valid flags for ext2fs_open()
81 * EXT2_FLAG_RW - Open the filesystem for read/write.
82 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
83 * features aren't supported.
84 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
86 errcode_t ext2fs_open2(const char *name, const char *io_options,
87 int flags, int superblock,
88 unsigned int block_size, io_manager manager,
93 unsigned long i, first_meta_bg;
95 int groups_per_block, blocks_per_group, io_flags;
96 blk_t group_block, blk;
98 #ifdef WORDS_BIGENDIAN
99 struct ext2_group_desc *gdp;
103 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
105 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
109 memset(fs, 0, sizeof(struct struct_ext2_filsys));
110 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
112 /* don't overwrite sb backups unless flag is explicitly cleared */
113 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
115 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
118 strcpy(fs->device_name, name);
119 cp = strchr(fs->device_name, '?');
120 if (!io_options && cp) {
126 if (flags & EXT2_FLAG_RW)
127 io_flags |= IO_FLAG_RW;
128 if (flags & EXT2_FLAG_EXCLUSIVE)
129 io_flags |= IO_FLAG_EXCLUSIVE;
130 retval = manager->open(fs->device_name, io_flags, &fs->io);
134 (retval = io_channel_set_options(fs->io, io_options)))
136 fs->image_io = fs->io;
137 fs->io->app_data = fs;
138 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);
141 if (flags & EXT2_FLAG_IMAGE_FILE) {
142 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
146 retval = io_channel_read_blk(fs->io, 0,
147 -(int)sizeof(struct ext2_image_hdr),
151 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
152 return EXT2_ET_MAGIC_E2IMAGE;
154 block_size = fs->image_header->fs_blocksize;
158 * If the user specifies a specific block # for the
159 * superblock, then he/she must also specify the block size!
160 * Otherwise, read the master superblock located at offset
161 * SUPERBLOCK_OFFSET from the start of the partition.
163 * Note: we only save a backup copy of the superblock if we
164 * are reading the superblock from the primary superblock location.
168 retval = EXT2_ET_INVALID_ARGUMENT;
171 io_channel_set_blksize(fs->io, block_size);
172 group_block = superblock;
175 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
178 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
182 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
187 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
189 #ifdef WORDS_BIGENDIAN
190 fs->flags |= EXT2_FLAG_SWAP_BYTES;
191 ext2fs_swap_super(fs->super);
193 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
194 retval = EXT2_ET_UNIMPLEMENTED;
199 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
200 retval = EXT2_ET_BAD_MAGIC;
203 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
204 retval = EXT2_ET_REV_TOO_HIGH;
209 * Check for feature set incompatibility
211 if (!(flags & EXT2_FLAG_FORCE)) {
212 features = fs->super->s_feature_incompat;
213 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
214 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
215 features &= !EXT2_LIB_SOFTSUPP_INCOMPAT;
217 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
218 retval = EXT2_ET_UNSUPP_FEATURE;
222 features = fs->super->s_feature_ro_compat;
223 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
224 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
225 features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT;
227 if ((flags & EXT2_FLAG_RW) &&
228 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
229 retval = EXT2_ET_RO_UNSUPP_FEATURE;
233 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
234 (fs->super->s_feature_incompat &
235 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
236 retval = EXT2_ET_UNSUPP_FEATURE;
241 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
242 EXT2_MAX_BLOCK_LOG_SIZE) {
243 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
246 fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
247 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
248 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
251 fs->fragsize = EXT2_FRAG_SIZE(fs->super);
252 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
253 EXT2_INODE_SIZE(fs->super) +
254 EXT2_BLOCK_SIZE(fs->super) - 1) /
255 EXT2_BLOCK_SIZE(fs->super));
257 if (block_size != fs->blocksize) {
258 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
263 * Set the blocksize to the filesystem's blocksize.
265 io_channel_set_blksize(fs->io, fs->blocksize);
268 * If this is an external journal device, don't try to read
269 * the group descriptors, because they're not there.
271 if (fs->super->s_feature_incompat &
272 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
273 fs->group_desc_count = 0;
278 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
279 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
284 * Read group descriptors
286 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
287 if (blocks_per_group == 0 ||
288 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
289 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
290 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
291 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
292 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
295 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
296 fs->super->s_first_data_block,
298 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
299 fs->super->s_inodes_count) {
300 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
303 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
304 EXT2_DESC_PER_BLOCK(fs->super));
305 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
310 group_block = fs->super->s_first_data_block;
311 dest = (char *) fs->group_desc;
312 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
313 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
314 first_meta_bg = fs->super->s_first_meta_bg;
316 first_meta_bg = fs->desc_blocks;
318 retval = io_channel_read_blk(fs->io, group_block+1,
319 first_meta_bg, dest);
322 #ifdef WORDS_BIGENDIAN
323 gdp = (struct ext2_group_desc *) dest;
324 for (j=0; j < groups_per_block*first_meta_bg; j++)
325 ext2fs_swap_group_desc(gdp++);
327 dest += fs->blocksize*first_meta_bg;
329 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
330 blk = ext2fs_descriptor_block_loc(fs, group_block, i);
331 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
334 #ifdef WORDS_BIGENDIAN
335 gdp = (struct ext2_group_desc *) dest;
336 for (j=0; j < groups_per_block; j++)
337 ext2fs_swap_group_desc(gdp++);
339 dest += fs->blocksize;
342 fs->stride = fs->super->s_raid_stride;
345 * If recovery is from backup superblock, Clear _UNININT flags &
346 * reset bg_itable_unused to zero
348 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
349 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
350 struct ext2_group_desc *gd;
353 for (group = 0; group < fs->group_desc_count; group++) {
354 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
355 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
356 ext2fs_bg_itable_unused_set(fs, group, 0);
358 ext2fs_mark_super_dirty(fs);
361 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
365 if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
373 * Set/get the filesystem data I/O channel.
375 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
377 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
379 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
380 return EXT2_ET_NOT_IMAGE_FILE;
382 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
387 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
389 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
390 return EXT2_ET_NOT_IMAGE_FILE;
391 fs->io = new_io ? new_io : fs->image_io;
395 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
397 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
398 return EXT2_ET_NOT_IMAGE_FILE;
399 fs->io = fs->image_io = new_io;
400 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
401 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
402 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;