4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
11 * linux/fs/minix/dir.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * ext4 directory handling functions
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
20 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
25 #include <linux/buffer_head.h>
26 #include <linux/slab.h>
30 static int ext4_dx_readdir(struct file *, struct dir_context *);
33 * Check if the given dir-inode refers to an htree-indexed directory
34 * (or a directory which could potentially get converted to use htree
37 * Return 1 if it is a dx dir, 0 if not
39 static int is_dx_dir(struct inode *inode)
41 struct super_block *sb = inode->i_sb;
43 if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
44 EXT4_FEATURE_COMPAT_DIR_INDEX) &&
45 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
46 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
47 ext4_has_inline_data(inode)))
54 * Return 0 if the directory entry is OK, and 1 if there is a problem
56 * Note: this is the opposite of what ext2 and ext3 historically returned...
58 * bh passed here can be an inode block or a dir data block, depending
59 * on the inode inline data flag.
61 int __ext4_check_dir_entry(const char *function, unsigned int line,
62 struct inode *dir, struct file *filp,
63 struct ext4_dir_entry_2 *de,
64 struct buffer_head *bh, char *buf, int size,
67 const char *error_msg = NULL;
68 const int rlen = ext4_rec_len_from_disk(de->rec_len,
69 dir->i_sb->s_blocksize);
71 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
72 error_msg = "rec_len is smaller than minimal";
73 else if (unlikely(rlen % 4 != 0))
74 error_msg = "rec_len % 4 != 0";
75 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
76 error_msg = "rec_len is too small for name_len";
77 else if (unlikely(((char *) de - buf) + rlen > size))
78 error_msg = "directory entry across range";
79 else if (unlikely(le32_to_cpu(de->inode) >
80 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
81 error_msg = "inode out of bounds";
86 ext4_error_file(filp, function, line, bh->b_blocknr,
87 "bad entry in directory: %s - offset=%u(%u), "
88 "inode=%u, rec_len=%d, name_len=%d",
89 error_msg, (unsigned) (offset % size),
90 offset, le32_to_cpu(de->inode),
93 ext4_error_inode(dir, function, line, bh->b_blocknr,
94 "bad entry in directory: %s - offset=%u(%u), "
95 "inode=%u, rec_len=%d, name_len=%d",
96 error_msg, (unsigned) (offset % size),
97 offset, le32_to_cpu(de->inode),
103 static int ext4_readdir(struct file *file, struct dir_context *ctx)
107 struct ext4_dir_entry_2 *de;
109 struct inode *inode = file_inode(file);
110 struct super_block *sb = inode->i_sb;
111 struct buffer_head *bh = NULL;
112 int dir_has_error = 0;
113 struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
115 if (is_dx_dir(inode)) {
116 err = ext4_dx_readdir(file, ctx);
117 if (err != ERR_BAD_DX_DIR) {
121 * We don't set the inode dirty flag since it's not
122 * critical that it get flushed back to the disk.
124 ext4_clear_inode_flag(file_inode(file),
128 if (ext4_has_inline_data(inode)) {
129 int has_inline_data = 1;
130 err = ext4_read_inline_dir(file, ctx,
136 if (ext4_encrypted_inode(inode)) {
137 err = ext4_fname_crypto_alloc_buffer(inode, EXT4_NAME_LEN,
143 offset = ctx->pos & (sb->s_blocksize - 1);
145 while (ctx->pos < inode->i_size) {
146 struct ext4_map_blocks map;
148 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
150 err = ext4_map_blocks(NULL, inode, &map, 0);
152 pgoff_t index = map.m_pblk >>
153 (PAGE_CACHE_SHIFT - inode->i_blkbits);
154 if (!ra_has_index(&file->f_ra, index))
155 page_cache_sync_readahead(
156 sb->s_bdev->bd_inode->i_mapping,
159 file->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
160 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
166 if (!dir_has_error) {
167 EXT4_ERROR_FILE(file, 0,
168 "directory contains a "
169 "hole at offset %llu",
170 (unsigned long long) ctx->pos);
173 /* corrupt size? Maybe no more blocks to read */
174 if (ctx->pos > inode->i_blocks << 9)
176 ctx->pos += sb->s_blocksize - offset;
180 /* Check the checksum */
181 if (!buffer_verified(bh) &&
182 !ext4_dirent_csum_verify(inode,
183 (struct ext4_dir_entry *)bh->b_data)) {
184 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
186 (unsigned long long)ctx->pos);
187 ctx->pos += sb->s_blocksize - offset;
192 set_buffer_verified(bh);
194 /* If the dir block has changed since the last call to
195 * readdir(2), then we might be pointing to an invalid
196 * dirent right now. Scan from the start of the block
198 if (file->f_version != inode->i_version) {
199 for (i = 0; i < sb->s_blocksize && i < offset; ) {
200 de = (struct ext4_dir_entry_2 *)
202 /* It's too expensive to do a full
203 * dirent test each time round this
204 * loop, but we do have to test at
205 * least that it is non-zero. A
206 * failure will be detected in the
207 * dirent test below. */
208 if (ext4_rec_len_from_disk(de->rec_len,
209 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
211 i += ext4_rec_len_from_disk(de->rec_len,
215 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
217 file->f_version = inode->i_version;
220 while (ctx->pos < inode->i_size
221 && offset < sb->s_blocksize) {
222 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
223 if (ext4_check_dir_entry(inode, file, de, bh,
224 bh->b_data, bh->b_size,
227 * On error, skip to the next block
229 ctx->pos = (ctx->pos |
230 (sb->s_blocksize - 1)) + 1;
233 offset += ext4_rec_len_from_disk(de->rec_len,
235 if (le32_to_cpu(de->inode)) {
236 if (!ext4_encrypted_inode(inode)) {
237 if (!dir_emit(ctx, de->name,
239 le32_to_cpu(de->inode),
240 get_dtype(sb, de->file_type)))
243 int save_len = fname_crypto_str.len;
245 /* Directory is encrypted */
246 err = ext4_fname_disk_to_usr(inode,
247 NULL, de, &fname_crypto_str);
248 fname_crypto_str.len = save_len;
252 fname_crypto_str.name, err,
253 le32_to_cpu(de->inode),
254 get_dtype(sb, de->file_type)))
258 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
261 if ((ctx->pos < inode->i_size) && !dir_relax(inode))
270 #ifdef CONFIG_EXT4_FS_ENCRYPTION
271 ext4_fname_crypto_free_buffer(&fname_crypto_str);
277 static inline int is_32bit_api(void)
280 return is_compat_task();
282 return (BITS_PER_LONG == 32);
287 * These functions convert from the major/minor hash to an f_pos
288 * value for dx directories
290 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
291 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
292 * directly on both 32-bit and 64-bit nodes, under such case, neither
293 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
295 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
297 if ((filp->f_mode & FMODE_32BITHASH) ||
298 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
301 return ((__u64)(major >> 1) << 32) | (__u64)minor;
304 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
306 if ((filp->f_mode & FMODE_32BITHASH) ||
307 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
308 return (pos << 1) & 0xffffffff;
310 return ((pos >> 32) << 1) & 0xffffffff;
313 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
315 if ((filp->f_mode & FMODE_32BITHASH) ||
316 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
319 return pos & 0xffffffff;
323 * Return 32- or 64-bit end-of-file for dx directories
325 static inline loff_t ext4_get_htree_eof(struct file *filp)
327 if ((filp->f_mode & FMODE_32BITHASH) ||
328 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
329 return EXT4_HTREE_EOF_32BIT;
331 return EXT4_HTREE_EOF_64BIT;
336 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
337 * directories, where the "offset" is in terms of the filename hash
338 * value instead of the byte offset.
340 * Because we may return a 64-bit hash that is well beyond offset limits,
341 * we need to pass the max hash as the maximum allowable offset in
342 * the htree directory case.
344 * For non-htree, ext4_llseek already chooses the proper max offset.
346 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
348 struct inode *inode = file->f_mapping->host;
349 int dx_dir = is_dx_dir(inode);
350 loff_t htree_max = ext4_get_htree_eof(file);
353 return generic_file_llseek_size(file, offset, whence,
354 htree_max, htree_max);
356 return ext4_llseek(file, offset, whence);
360 * This structure holds the nodes of the red-black tree used to store
361 * the directory entry in hash order.
366 struct rb_node rb_hash;
375 * This functoin implements a non-recursive way of freeing all of the
376 * nodes in the red-black tree.
378 static void free_rb_tree_fname(struct rb_root *root)
380 struct fname *fname, *next;
382 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
384 struct fname *old = fname;
393 static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
396 struct dir_private_info *p;
398 p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
401 p->curr_hash = pos2maj_hash(filp, pos);
402 p->curr_minor_hash = pos2min_hash(filp, pos);
406 void ext4_htree_free_dir_info(struct dir_private_info *p)
408 free_rb_tree_fname(&p->root);
413 * Given a directory entry, enter it into the fname rb tree.
415 * When filename encryption is enabled, the dirent will hold the
416 * encrypted filename, while the htree will hold decrypted filename.
417 * The decrypted filename is passed in via ent_name. parameter.
419 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
421 struct ext4_dir_entry_2 *dirent,
422 struct ext4_str *ent_name)
424 struct rb_node **p, *parent = NULL;
425 struct fname *fname, *new_fn;
426 struct dir_private_info *info;
429 info = dir_file->private_data;
430 p = &info->root.rb_node;
432 /* Create and allocate the fname structure */
433 len = sizeof(struct fname) + ent_name->len + 1;
434 new_fn = kzalloc(len, GFP_KERNEL);
438 new_fn->minor_hash = minor_hash;
439 new_fn->inode = le32_to_cpu(dirent->inode);
440 new_fn->name_len = ent_name->len;
441 new_fn->file_type = dirent->file_type;
442 memcpy(new_fn->name, ent_name->name, ent_name->len);
443 new_fn->name[ent_name->len] = 0;
447 fname = rb_entry(parent, struct fname, rb_hash);
450 * If the hash and minor hash match up, then we put
451 * them on a linked list. This rarely happens...
453 if ((new_fn->hash == fname->hash) &&
454 (new_fn->minor_hash == fname->minor_hash)) {
455 new_fn->next = fname->next;
456 fname->next = new_fn;
460 if (new_fn->hash < fname->hash)
462 else if (new_fn->hash > fname->hash)
464 else if (new_fn->minor_hash < fname->minor_hash)
466 else /* if (new_fn->minor_hash > fname->minor_hash) */
470 rb_link_node(&new_fn->rb_hash, parent, p);
471 rb_insert_color(&new_fn->rb_hash, &info->root);
478 * This is a helper function for ext4_dx_readdir. It calls filldir
479 * for all entres on the fname linked list. (Normally there is only
480 * one entry on the linked list, unless there are 62 bit hash collisions.)
482 static int call_filldir(struct file *file, struct dir_context *ctx,
485 struct dir_private_info *info = file->private_data;
486 struct inode *inode = file_inode(file);
487 struct super_block *sb = inode->i_sb;
490 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
491 "called with null fname?!?", __func__, __LINE__,
492 inode->i_ino, current->comm);
495 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
497 if (!dir_emit(ctx, fname->name,
500 get_dtype(sb, fname->file_type))) {
501 info->extra_fname = fname;
509 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
511 struct dir_private_info *info = file->private_data;
512 struct inode *inode = file_inode(file);
517 info = ext4_htree_create_dir_info(file, ctx->pos);
520 file->private_data = info;
523 if (ctx->pos == ext4_get_htree_eof(file))
526 /* Some one has messed with f_pos; reset the world */
527 if (info->last_pos != ctx->pos) {
528 free_rb_tree_fname(&info->root);
529 info->curr_node = NULL;
530 info->extra_fname = NULL;
531 info->curr_hash = pos2maj_hash(file, ctx->pos);
532 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
536 * If there are any leftover names on the hash collision
537 * chain, return them first.
539 if (info->extra_fname) {
540 if (call_filldir(file, ctx, info->extra_fname))
542 info->extra_fname = NULL;
544 } else if (!info->curr_node)
545 info->curr_node = rb_first(&info->root);
549 * Fill the rbtree if we have no more entries,
550 * or the inode has changed since we last read in the
553 if ((!info->curr_node) ||
554 (file->f_version != inode->i_version)) {
555 info->curr_node = NULL;
556 free_rb_tree_fname(&info->root);
557 file->f_version = inode->i_version;
558 ret = ext4_htree_fill_tree(file, info->curr_hash,
559 info->curr_minor_hash,
564 ctx->pos = ext4_get_htree_eof(file);
567 info->curr_node = rb_first(&info->root);
570 fname = rb_entry(info->curr_node, struct fname, rb_hash);
571 info->curr_hash = fname->hash;
572 info->curr_minor_hash = fname->minor_hash;
573 if (call_filldir(file, ctx, fname))
576 info->curr_node = rb_next(info->curr_node);
577 if (info->curr_node) {
578 fname = rb_entry(info->curr_node, struct fname,
580 info->curr_hash = fname->hash;
581 info->curr_minor_hash = fname->minor_hash;
583 if (info->next_hash == ~0) {
584 ctx->pos = ext4_get_htree_eof(file);
587 info->curr_hash = info->next_hash;
588 info->curr_minor_hash = 0;
592 info->last_pos = ctx->pos;
596 static int ext4_dir_open(struct inode * inode, struct file * filp)
598 if (ext4_encrypted_inode(inode))
599 return ext4_get_encryption_info(inode) ? -EACCES : 0;
603 static int ext4_release_dir(struct inode *inode, struct file *filp)
605 if (filp->private_data)
606 ext4_htree_free_dir_info(filp->private_data);
611 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
614 struct ext4_dir_entry_2 *de;
616 unsigned int offset = 0;
619 de = (struct ext4_dir_entry_2 *)buf;
620 top = buf + buf_size;
621 while ((char *) de < top) {
622 if (ext4_check_dir_entry(dir, NULL, de, bh,
623 buf, buf_size, offset))
625 nlen = EXT4_DIR_REC_LEN(de->name_len);
626 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
627 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
630 if ((char *) de > top)
636 const struct file_operations ext4_dir_operations = {
637 .llseek = ext4_dir_llseek,
638 .read = generic_read_dir,
639 .iterate = ext4_readdir,
640 .unlocked_ioctl = ext4_ioctl,
642 .compat_ioctl = ext4_compat_ioctl,
644 .fsync = ext4_sync_file,
645 .open = ext4_dir_open,
646 .release = ext4_release_dir,