2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
6 * Copyright (c) 2012 Martin Sucha
7 * Copyright (c) 2012 Frantisek Princ
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
14 * - Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * - Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * - The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 /** @addtogroup lwext4
39 * @brief Directory handle procedures.
42 #include "ext4_config.h"
43 #include "ext4_types.h"
44 #include "ext4_misc.h"
45 #include "ext4_errno.h"
46 #include "ext4_debug.h"
48 #include "ext4_trans.h"
50 #include "ext4_dir_idx.h"
51 #include "ext4_crc32.h"
52 #include "ext4_inode.h"
57 /****************************************************************************/
59 /* Walk through a dirent block to find a checksum "dirent" at the tail */
60 static struct ext4_dir_entry_tail *
61 ext4_dir_get_tail(struct ext4_inode_ref *inode_ref,
62 struct ext4_dir_en *de)
64 struct ext4_dir_entry_tail *t;
65 struct ext4_sblock *sb = &inode_ref->fs->sb;
67 t = EXT4_DIRENT_TAIL(de, ext4_sb_get_block_size(sb));
69 if (t->reserved_zero1 || t->reserved_zero2)
71 if (to_le16(t->rec_len) != sizeof(struct ext4_dir_entry_tail))
73 if (t->reserved_ft != EXT4_DIRENTRY_DIR_CSUM)
79 #if CONFIG_META_CSUM_ENABLE
80 static uint32_t ext4_dir_csum(struct ext4_inode_ref *inode_ref,
81 struct ext4_dir_en *dirent, int size)
84 struct ext4_sblock *sb = &inode_ref->fs->sb;
85 uint32_t ino_index = to_le32(inode_ref->index);
86 uint32_t ino_gen = to_le32(ext4_inode_get_generation(inode_ref->inode));
88 /* First calculate crc32 checksum against fs uuid */
89 csum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
90 /* Then calculate crc32 checksum against inode number
91 * and inode generation */
92 csum = ext4_crc32c(csum, &ino_index, sizeof(ino_index));
93 csum = ext4_crc32c(csum, &ino_gen, sizeof(ino_gen));
94 /* Finally calculate crc32 checksum against directory entries */
95 csum = ext4_crc32c(csum, dirent, size);
99 #define ext4_dir_csum(...) 0
102 bool ext4_dir_csum_verify(struct ext4_inode_ref *inode_ref,
103 struct ext4_dir_en *dirent)
105 #ifdef CONFIG_META_CSUM_ENABLE
106 struct ext4_dir_entry_tail *t;
107 struct ext4_sblock *sb = &inode_ref->fs->sb;
109 /* Compute the checksum only if the filesystem supports it */
110 if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
111 t = ext4_dir_get_tail(inode_ref, dirent);
113 /* There is no space to hold the checksum */
117 ptrdiff_t __unused diff = (char *)t - (char *)dirent;
118 uint32_t csum = ext4_dir_csum(inode_ref, dirent, diff);
119 if (t->checksum != to_le32(csum))
127 void ext4_dir_init_entry_tail(struct ext4_dir_entry_tail *t)
129 memset(t, 0, sizeof(struct ext4_dir_entry_tail));
130 t->rec_len = to_le16(sizeof(struct ext4_dir_entry_tail));
131 t->reserved_ft = EXT4_DIRENTRY_DIR_CSUM;
134 void ext4_dir_set_csum(struct ext4_inode_ref *inode_ref,
135 struct ext4_dir_en *dirent)
137 struct ext4_dir_entry_tail *t;
138 struct ext4_sblock *sb = &inode_ref->fs->sb;
140 /* Compute the checksum only if the filesystem supports it */
141 if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
142 t = ext4_dir_get_tail(inode_ref, dirent);
144 /* There is no space to hold the checksum */
148 ptrdiff_t __unused diff = (char *)t - (char *)dirent;
149 uint32_t csum = ext4_dir_csum(inode_ref, dirent, diff);
150 t->checksum = to_le32(csum);
154 /**@brief Do some checks before returning iterator.
155 * @param it Iterator to be checked
156 * @param block_size Size of data block
159 static int ext4_dir_iterator_set(struct ext4_dir_iter *it,
162 uint32_t off_in_block = it->curr_off % block_size;
163 struct ext4_sblock *sb = &it->inode_ref->fs->sb;
167 /* Ensure proper alignment */
168 if ((off_in_block % 4) != 0)
171 /* Ensure that the core of the entry does not overflow the block */
172 if (off_in_block > block_size - 8)
175 struct ext4_dir_en *en;
176 en = (void *)(it->curr_blk.data + off_in_block);
178 /* Ensure that the whole entry does not overflow the block */
179 uint16_t length = ext4_dir_en_get_entry_len(en);
180 if (off_in_block + length > block_size)
183 /* Ensure the name length is not too large */
184 if (ext4_dir_en_get_name_len(sb, en) > length - 8)
187 /* Everything OK - "publish" the entry */
192 /**@brief Seek to next valid directory entry.
193 * Here can be jumped to the next data block.
194 * @param it Initialized iterator
195 * @param pos Position of the next entry
198 static int ext4_dir_iterator_seek(struct ext4_dir_iter *it, uint64_t pos)
200 struct ext4_sblock *sb = &it->inode_ref->fs->sb;
201 struct ext4_inode *inode = it->inode_ref->inode;
202 struct ext4_blockdev *bdev = it->inode_ref->fs->bdev;
203 uint64_t size = ext4_inode_get_size(sb, inode);
206 /* The iterator is not valid until we seek to the desired position */
209 /* Are we at the end? */
211 if (it->curr_blk.lb_id) {
213 r = ext4_block_set(bdev, &it->curr_blk);
214 it->curr_blk.lb_id = 0;
223 /* Compute next block address */
224 uint32_t block_size = ext4_sb_get_block_size(sb);
225 uint64_t current_blk_idx = it->curr_off / block_size;
226 uint32_t next_blk_idx = (uint32_t)(pos / block_size);
229 * If we don't have a block or are moving across block boundary,
230 * we need to get another block
232 if ((it->curr_blk.lb_id == 0) ||
233 (current_blk_idx != next_blk_idx)) {
234 if (it->curr_blk.lb_id) {
235 r = ext4_block_set(bdev, &it->curr_blk);
236 it->curr_blk.lb_id = 0;
242 ext4_fsblk_t next_blk;
243 r = ext4_fs_get_inode_dblk_idx(it->inode_ref, next_blk_idx,
248 r = ext4_trans_block_get(bdev, &it->curr_blk, next_blk);
250 it->curr_blk.lb_id = 0;
256 return ext4_dir_iterator_set(it, block_size);
259 int ext4_dir_iterator_init(struct ext4_dir_iter *it,
260 struct ext4_inode_ref *inode_ref, uint64_t pos)
262 it->inode_ref = inode_ref;
265 it->curr_blk.lb_id = 0;
267 return ext4_dir_iterator_seek(it, pos);
270 int ext4_dir_iterator_next(struct ext4_dir_iter *it)
276 skip = ext4_dir_en_get_entry_len(it->curr);
277 r = ext4_dir_iterator_seek(it, it->curr_off + skip);
281 /*Skip NULL referenced entry*/
282 if (ext4_dir_en_get_inode(it->curr) != 0)
289 int ext4_dir_iterator_fini(struct ext4_dir_iter *it)
293 if (it->curr_blk.lb_id)
294 return ext4_block_set(it->inode_ref->fs->bdev, &it->curr_blk);
299 void ext4_dir_write_entry(struct ext4_sblock *sb, struct ext4_dir_en *en,
300 uint16_t entry_len, struct ext4_inode_ref *child,
301 const char *name, size_t name_len)
303 /* Check maximum entry length */
304 ext4_assert(entry_len <= ext4_sb_get_block_size(sb));
306 /* Set type of entry */
307 switch (ext4_inode_type(sb, child->inode)) {
308 case EXT4_INODE_MODE_DIRECTORY:
309 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_DIR);
311 case EXT4_INODE_MODE_FILE:
312 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_REG_FILE);
314 case EXT4_INODE_MODE_SOFTLINK:
315 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_SYMLINK);
317 case EXT4_INODE_MODE_CHARDEV:
318 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_CHRDEV);
320 case EXT4_INODE_MODE_BLOCKDEV:
321 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_BLKDEV);
323 case EXT4_INODE_MODE_FIFO:
324 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_FIFO);
326 case EXT4_INODE_MODE_SOCKET:
327 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_SOCK);
330 /* FIXME: unsupported filetype */
331 ext4_dir_en_set_inode_type(sb, en, EXT4_DE_UNKNOWN);
334 /* Set basic attributes */
335 ext4_dir_en_set_inode(en, child->index);
336 ext4_dir_en_set_entry_len(en, entry_len);
337 ext4_dir_en_set_name_len(sb, en, (uint16_t)name_len);
340 memcpy(en->name, name, name_len);
343 int ext4_dir_add_entry(struct ext4_inode_ref *parent, const char *name,
344 uint32_t name_len, struct ext4_inode_ref *child)
347 struct ext4_fs *fs = parent->fs;
348 struct ext4_sblock *sb = &parent->fs->sb;
350 #if CONFIG_DIR_INDEX_ENABLE
351 /* Index adding (if allowed) */
352 if ((ext4_sb_feature_com(sb, EXT4_FCOM_DIR_INDEX)) &&
353 (ext4_inode_has_flag(parent->inode, EXT4_INODE_FLAG_INDEX))) {
354 r = ext4_dir_dx_add_entry(parent, child, name);
356 /* Check if index is not corrupted */
357 if (r != EXT4_ERR_BAD_DX_DIR) {
364 /* Needed to clear dir index flag if corrupted */
365 ext4_inode_clear_flag(parent->inode, EXT4_INODE_FLAG_INDEX);
366 parent->dirty = true;
370 /* Linear algorithm */
372 ext4_fsblk_t fblock = 0;
373 uint32_t block_size = ext4_sb_get_block_size(sb);
374 uint64_t inode_size = ext4_inode_get_size(sb, parent->inode);
375 uint32_t total_blocks = (uint32_t)(inode_size / block_size);
377 /* Find block, where is space for new entry and try to add */
378 bool success = false;
379 for (iblock = 0; iblock < total_blocks; ++iblock) {
380 r = ext4_fs_get_inode_dblk_idx(parent, iblock, &fblock, false);
384 struct ext4_block block;
385 r = ext4_trans_block_get(fs->bdev, &block, fblock);
389 if (!ext4_dir_csum_verify(parent, (void *)block.data)) {
391 DBG_WARN "Leaf block checksum failed."
392 "Inode: %" PRIu32", "
393 "Block: %" PRIu32"\n",
398 /* If adding is successful, function can finish */
399 r = ext4_dir_try_insert_entry(sb, parent, &block, child,
404 r = ext4_block_set(fs->bdev, &block);
412 /* No free block found - needed to allocate next data block */
416 r = ext4_fs_append_inode_dblk(parent, &fblock, &iblock);
423 r = ext4_trans_block_get_noread(fs->bdev, &b, fblock);
427 /* Fill block with zeroes */
428 memset(b.data, 0, block_size);
429 struct ext4_dir_en *blk_en = (void *)b.data;
432 if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
433 uint16_t el = block_size - sizeof(struct ext4_dir_entry_tail);
434 ext4_dir_write_entry(sb, blk_en, el, child, name, name_len);
435 ext4_dir_init_entry_tail(EXT4_DIRENT_TAIL(b.data, block_size));
437 ext4_dir_write_entry(sb, blk_en, block_size, child, name,
441 ext4_dir_set_csum(parent, (void *)b.data);
442 ext4_trans_set_block_dirty(b.buf);
443 r = ext4_block_set(fs->bdev, &b);
448 int ext4_dir_find_entry(struct ext4_dir_search_result *result,
449 struct ext4_inode_ref *parent, const char *name,
453 struct ext4_sblock *sb = &parent->fs->sb;
456 result->block.lb_id = 0;
457 result->dentry = NULL;
459 #if CONFIG_DIR_INDEX_ENABLE
461 if ((ext4_sb_feature_com(sb, EXT4_FCOM_DIR_INDEX)) &&
462 (ext4_inode_has_flag(parent->inode, EXT4_INODE_FLAG_INDEX))) {
463 r = ext4_dir_dx_find_entry(result, parent, name_len, name);
464 /* Check if index is not corrupted */
465 if (r != EXT4_ERR_BAD_DX_DIR) {
472 /* Needed to clear dir index flag if corrupted */
473 ext4_inode_clear_flag(parent->inode, EXT4_INODE_FLAG_INDEX);
474 parent->dirty = true;
478 /* Linear algorithm */
482 uint32_t block_size = ext4_sb_get_block_size(sb);
483 uint64_t inode_size = ext4_inode_get_size(sb, parent->inode);
484 uint32_t total_blocks = (uint32_t)(inode_size / block_size);
486 /* Walk through all data blocks */
487 for (iblock = 0; iblock < total_blocks; ++iblock) {
488 /* Load block address */
489 r = ext4_fs_get_inode_dblk_idx(parent, iblock, &fblock, false);
493 /* Load data block */
495 r = ext4_trans_block_get(parent->fs->bdev, &b, fblock);
499 if (!ext4_dir_csum_verify(parent, (void *)b.data)) {
501 DBG_WARN "Leaf block checksum failed."
502 "Inode: %" PRIu32", "
503 "Block: %" PRIu32"\n",
508 /* Try to find entry in block */
509 struct ext4_dir_en *res_entry;
510 r = ext4_dir_find_in_block(&b, sb, name_len, name, &res_entry);
513 result->dentry = res_entry;
517 /* Entry not found - put block and continue to the next block */
519 r = ext4_block_set(parent->fs->bdev, &b);
527 int ext4_dir_remove_entry(struct ext4_inode_ref *parent, const char *name,
530 struct ext4_sblock *sb = &parent->fs->sb;
531 /* Check if removing from directory */
532 if (!ext4_inode_is_type(sb, parent->inode, EXT4_INODE_MODE_DIRECTORY))
535 /* Try to find entry */
536 struct ext4_dir_search_result result;
537 int rc = ext4_dir_find_entry(&result, parent, name, name_len);
541 /* Invalidate entry */
542 ext4_dir_en_set_inode(result.dentry, 0);
544 /* Store entry position in block */
545 uint32_t pos = (uint8_t *)result.dentry - result.block.data;
548 * If entry is not the first in block, it must be merged
549 * with previous entry
554 /* Start from the first entry in block */
555 struct ext4_dir_en *tmp_de =(void *)result.block.data;
556 uint16_t de_len = ext4_dir_en_get_entry_len(tmp_de);
558 /* Find direct predecessor of removed entry */
559 while ((offset + de_len) < pos) {
560 offset += ext4_dir_en_get_entry_len(tmp_de);
561 tmp_de = (void *)(result.block.data + offset);
562 de_len = ext4_dir_en_get_entry_len(tmp_de);
565 ext4_assert(de_len + offset == pos);
567 /* Add to removed entry length to predecessor's length */
569 del_len = ext4_dir_en_get_entry_len(result.dentry);
570 ext4_dir_en_set_entry_len(tmp_de, de_len + del_len);
573 ext4_dir_set_csum(parent,
574 (struct ext4_dir_en *)result.block.data);
575 ext4_trans_set_block_dirty(result.block.buf);
577 return ext4_dir_destroy_result(parent, &result);
580 int ext4_dir_try_insert_entry(struct ext4_sblock *sb,
581 struct ext4_inode_ref *inode_ref,
582 struct ext4_block *dst_blk,
583 struct ext4_inode_ref *child, const char *name,
586 /* Compute required length entry and align it to 4 bytes */
587 uint32_t block_size = ext4_sb_get_block_size(sb);
588 uint16_t required_len = sizeof(struct ext4_fake_dir_entry) + name_len;
590 if ((required_len % 4) != 0)
591 required_len += 4 - (required_len % 4);
593 /* Initialize pointers, stop means to upper bound */
594 struct ext4_dir_en *start = (void *)dst_blk->data;
595 struct ext4_dir_en *stop = (void *)(dst_blk->data + block_size);
598 * Walk through the block and check for invalid entries
599 * or entries with free space for new entry
601 while (start < stop) {
602 uint32_t inode = ext4_dir_en_get_inode(start);
603 uint16_t rec_len = ext4_dir_en_get_entry_len(start);
604 uint8_t itype = ext4_dir_en_get_inode_type(sb, start);
606 /* If invalid and large enough entry, use it */
607 if ((inode == 0) && (itype != EXT4_DIRENTRY_DIR_CSUM) &&
608 (rec_len >= required_len)) {
609 ext4_dir_write_entry(sb, start, rec_len, child, name,
611 ext4_dir_set_csum(inode_ref, (void *)dst_blk->data);
612 ext4_trans_set_block_dirty(dst_blk->buf);
617 /* Valid entry, try to split it */
620 used_len = ext4_dir_en_get_name_len(sb, start);
623 sz = sizeof(struct ext4_fake_dir_entry) + used_len;
625 if ((used_len % 4) != 0)
626 sz += 4 - (used_len % 4);
628 uint16_t free_space = rec_len - sz;
630 /* There is free space for new entry */
631 if (free_space >= required_len) {
632 /* Cut tail of current entry */
633 struct ext4_dir_en * new_entry;
634 new_entry = (void *)((uint8_t *)start + sz);
635 ext4_dir_en_set_entry_len(start, sz);
636 ext4_dir_write_entry(sb, new_entry, free_space,
637 child, name, name_len);
639 ext4_dir_set_csum(inode_ref,
640 (void *)dst_blk->data);
641 ext4_trans_set_block_dirty(dst_blk->buf);
646 /* Jump to the next entry */
647 start = (void *)((uint8_t *)start + rec_len);
650 /* No free space found for new entry */
654 int ext4_dir_find_in_block(struct ext4_block *block, struct ext4_sblock *sb,
655 size_t name_len, const char *name,
656 struct ext4_dir_en **res_entry)
658 /* Start from the first entry in block */
659 struct ext4_dir_en *de = (struct ext4_dir_en *)block->data;
661 /* Set upper bound for cycling */
662 uint8_t *addr_limit = block->data + ext4_sb_get_block_size(sb);
664 /* Walk through the block and check entries */
665 while ((uint8_t *)de < addr_limit) {
666 /* Termination condition */
667 if ((uint8_t *)de + name_len > addr_limit)
670 /* Valid entry - check it */
671 if (ext4_dir_en_get_inode(de) != 0) {
672 /* For more efficient compare only lengths firstly*/
673 uint16_t el = ext4_dir_en_get_name_len(sb, de);
674 if (el == name_len) {
676 if (memcmp(name, de->name, name_len) == 0) {
683 uint16_t de_len = ext4_dir_en_get_entry_len(de);
685 /* Corrupted entry */
689 /* Jump to next entry */
690 de = (struct ext4_dir_en *)((uint8_t *)de + de_len);
693 /* Entry not found */
697 int ext4_dir_destroy_result(struct ext4_inode_ref *parent,
698 struct ext4_dir_search_result *result)
700 if (result->block.lb_id)
701 return ext4_block_set(parent->fs->bdev, &result->block);