xref: /linux/fs/ext4/dir.c (revision 5c2a430e85994f4873ea5ec42091baa1153bc731)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/dir.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Laboratoire MASI - Institut Blaise Pascal
8  * Universite Pierre et Marie Curie (Paris VI)
9  *
10  *  from
11  *
12  *  linux/fs/minix/dir.c
13  *
14  *  Copyright (C) 1991, 1992  Linus Torvalds
15  *
16  *  ext4 directory handling functions
17  *
18  *  Big-endian to little-endian byte-swapping/bitmaps by
19  *        David S. Miller (davem@caip.rutgers.edu), 1995
20  *
21  * Hash Tree Directory indexing (c) 2001  Daniel Phillips
22  *
23  */
24 
25 #include <linux/fs.h>
26 #include <linux/buffer_head.h>
27 #include <linux/slab.h>
28 #include <linux/iversion.h>
29 #include <linux/unicode.h>
30 #include "ext4.h"
31 #include "xattr.h"
32 
33 static int ext4_dx_readdir(struct file *, struct dir_context *);
34 
35 /**
36  * is_dx_dir() - check if a directory is using htree indexing
37  * @inode: directory inode
38  *
39  * Check if the given dir-inode refers to an htree-indexed directory
40  * (or a directory which could potentially get converted to use htree
41  * indexing).
42  *
43  * Return 1 if it is a dx dir, 0 if not
44  */
is_dx_dir(struct inode * inode)45 static int is_dx_dir(struct inode *inode)
46 {
47 	struct super_block *sb = inode->i_sb;
48 
49 	if (ext4_has_feature_dir_index(inode->i_sb) &&
50 	    ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
51 	     ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
52 	     ext4_has_inline_data(inode)))
53 		return 1;
54 
55 	return 0;
56 }
57 
is_fake_dir_entry(struct ext4_dir_entry_2 * de)58 static bool is_fake_dir_entry(struct ext4_dir_entry_2 *de)
59 {
60 	/* Check if . or .. , or skip if namelen is 0 */
61 	if ((de->name_len > 0) && (de->name_len <= 2) && (de->name[0] == '.') &&
62 	    (de->name[1] == '.' || de->name[1] == '\0'))
63 		return true;
64 	/* Check if this is a csum entry */
65 	if (de->file_type == EXT4_FT_DIR_CSUM)
66 		return true;
67 	return false;
68 }
69 
70 /*
71  * Return 0 if the directory entry is OK, and 1 if there is a problem
72  *
73  * Note: this is the opposite of what ext2 and ext3 historically returned...
74  *
75  * bh passed here can be an inode block or a dir data block, depending
76  * on the inode inline data flag.
77  */
__ext4_check_dir_entry(const char * function,unsigned int line,struct inode * dir,struct file * filp,struct ext4_dir_entry_2 * de,struct buffer_head * bh,char * buf,int size,unsigned int offset)78 int __ext4_check_dir_entry(const char *function, unsigned int line,
79 			   struct inode *dir, struct file *filp,
80 			   struct ext4_dir_entry_2 *de,
81 			   struct buffer_head *bh, char *buf, int size,
82 			   unsigned int offset)
83 {
84 	const char *error_msg = NULL;
85 	const int rlen = ext4_rec_len_from_disk(de->rec_len,
86 						dir->i_sb->s_blocksize);
87 	const int next_offset = ((char *) de - buf) + rlen;
88 	bool fake = is_fake_dir_entry(de);
89 	bool has_csum = ext4_has_feature_metadata_csum(dir->i_sb);
90 
91 	if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir)))
92 		error_msg = "rec_len is smaller than minimal";
93 	else if (unlikely(rlen % 4 != 0))
94 		error_msg = "rec_len % 4 != 0";
95 	else if (unlikely(rlen < ext4_dir_rec_len(de->name_len,
96 							fake ? NULL : dir)))
97 		error_msg = "rec_len is too small for name_len";
98 	else if (unlikely(next_offset > size))
99 		error_msg = "directory entry overrun";
100 	else if (unlikely(next_offset > size - ext4_dir_rec_len(1,
101 						  has_csum ? NULL : dir) &&
102 			  next_offset != size))
103 		error_msg = "directory entry too close to block end";
104 	else if (unlikely(le32_to_cpu(de->inode) >
105 			le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
106 		error_msg = "inode out of bounds";
107 	else if (unlikely(next_offset == size && de->name_len == 1 &&
108 			  de->name[0] == '.'))
109 		error_msg = "'.' directory cannot be the last in data block";
110 	else
111 		return 0;
112 
113 	if (filp)
114 		ext4_error_file(filp, function, line, bh->b_blocknr,
115 				"bad entry in directory: %s - offset=%u, "
116 				"inode=%u, rec_len=%d, size=%d fake=%d",
117 				error_msg, offset, le32_to_cpu(de->inode),
118 				rlen, size, fake);
119 	else
120 		ext4_error_inode(dir, function, line, bh->b_blocknr,
121 				"bad entry in directory: %s - offset=%u, "
122 				"inode=%u, rec_len=%d, size=%d fake=%d",
123 				 error_msg, offset, le32_to_cpu(de->inode),
124 				 rlen, size, fake);
125 
126 	return 1;
127 }
128 
ext4_readdir(struct file * file,struct dir_context * ctx)129 static int ext4_readdir(struct file *file, struct dir_context *ctx)
130 {
131 	unsigned int offset;
132 	int i;
133 	struct ext4_dir_entry_2 *de;
134 	int err;
135 	struct inode *inode = file_inode(file);
136 	struct super_block *sb = inode->i_sb;
137 	struct buffer_head *bh = NULL;
138 	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
139 	struct dir_private_info *info = file->private_data;
140 
141 	err = fscrypt_prepare_readdir(inode);
142 	if (err)
143 		return err;
144 
145 	if (is_dx_dir(inode)) {
146 		err = ext4_dx_readdir(file, ctx);
147 		if (err != ERR_BAD_DX_DIR)
148 			return err;
149 
150 		/* Can we just clear INDEX flag to ignore htree information? */
151 		if (!ext4_has_feature_metadata_csum(sb)) {
152 			/*
153 			 * We don't set the inode dirty flag since it's not
154 			 * critical that it gets flushed back to the disk.
155 			 */
156 			ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
157 		}
158 	}
159 
160 	if (ext4_has_inline_data(inode)) {
161 		int has_inline_data = 1;
162 		err = ext4_read_inline_dir(file, ctx,
163 					   &has_inline_data);
164 		if (has_inline_data)
165 			return err;
166 	}
167 
168 	if (IS_ENCRYPTED(inode)) {
169 		err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr);
170 		if (err < 0)
171 			return err;
172 	}
173 
174 	while (ctx->pos < inode->i_size) {
175 		struct ext4_map_blocks map;
176 
177 		if (fatal_signal_pending(current)) {
178 			err = -ERESTARTSYS;
179 			goto errout;
180 		}
181 		cond_resched();
182 		offset = ctx->pos & (sb->s_blocksize - 1);
183 		map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
184 		map.m_len = 1;
185 		err = ext4_map_blocks(NULL, inode, &map, 0);
186 		if (err == 0) {
187 			/* m_len should never be zero but let's avoid
188 			 * an infinite loop if it somehow is */
189 			if (map.m_len == 0)
190 				map.m_len = 1;
191 			ctx->pos += map.m_len * sb->s_blocksize;
192 			continue;
193 		}
194 		if (err > 0) {
195 			pgoff_t index = map.m_pblk >>
196 					(PAGE_SHIFT - inode->i_blkbits);
197 			if (!ra_has_index(&file->f_ra, index))
198 				page_cache_sync_readahead(
199 					sb->s_bdev->bd_mapping,
200 					&file->f_ra, file,
201 					index, 1);
202 			file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
203 			bh = ext4_bread(NULL, inode, map.m_lblk, 0);
204 			if (IS_ERR(bh)) {
205 				err = PTR_ERR(bh);
206 				bh = NULL;
207 				goto errout;
208 			}
209 		}
210 
211 		if (!bh) {
212 			/* corrupt size?  Maybe no more blocks to read */
213 			if (ctx->pos > inode->i_blocks << 9)
214 				break;
215 			ctx->pos += sb->s_blocksize - offset;
216 			continue;
217 		}
218 
219 		/* Check the checksum */
220 		if (!buffer_verified(bh) &&
221 		    !ext4_dirblock_csum_verify(inode, bh)) {
222 			EXT4_ERROR_FILE(file, 0, "directory fails checksum "
223 					"at offset %llu",
224 					(unsigned long long)ctx->pos);
225 			ctx->pos += sb->s_blocksize - offset;
226 			brelse(bh);
227 			bh = NULL;
228 			continue;
229 		}
230 		set_buffer_verified(bh);
231 
232 		/* If the dir block has changed since the last call to
233 		 * readdir(2), then we might be pointing to an invalid
234 		 * dirent right now.  Scan from the start of the block
235 		 * to make sure. */
236 		if (!inode_eq_iversion(inode, info->cookie)) {
237 			for (i = 0; i < sb->s_blocksize && i < offset; ) {
238 				de = (struct ext4_dir_entry_2 *)
239 					(bh->b_data + i);
240 				/* It's too expensive to do a full
241 				 * dirent test each time round this
242 				 * loop, but we do have to test at
243 				 * least that it is non-zero.  A
244 				 * failure will be detected in the
245 				 * dirent test below. */
246 				if (ext4_rec_len_from_disk(de->rec_len,
247 					sb->s_blocksize) < ext4_dir_rec_len(1,
248 									inode))
249 					break;
250 				i += ext4_rec_len_from_disk(de->rec_len,
251 							    sb->s_blocksize);
252 			}
253 			offset = i;
254 			ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
255 				| offset;
256 			info->cookie = inode_query_iversion(inode);
257 		}
258 
259 		while (ctx->pos < inode->i_size
260 		       && offset < sb->s_blocksize) {
261 			de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
262 			if (ext4_check_dir_entry(inode, file, de, bh,
263 						 bh->b_data, bh->b_size,
264 						 offset)) {
265 				/*
266 				 * On error, skip to the next block
267 				 */
268 				ctx->pos = (ctx->pos |
269 						(sb->s_blocksize - 1)) + 1;
270 				break;
271 			}
272 			offset += ext4_rec_len_from_disk(de->rec_len,
273 					sb->s_blocksize);
274 			if (le32_to_cpu(de->inode)) {
275 				if (!IS_ENCRYPTED(inode)) {
276 					if (!dir_emit(ctx, de->name,
277 					    de->name_len,
278 					    le32_to_cpu(de->inode),
279 					    get_dtype(sb, de->file_type)))
280 						goto done;
281 				} else {
282 					int save_len = fstr.len;
283 					struct fscrypt_str de_name =
284 							FSTR_INIT(de->name,
285 								de->name_len);
286 					u32 hash;
287 					u32 minor_hash;
288 
289 					if (IS_CASEFOLDED(inode)) {
290 						hash = EXT4_DIRENT_HASH(de);
291 						minor_hash = EXT4_DIRENT_MINOR_HASH(de);
292 					} else {
293 						hash = 0;
294 						minor_hash = 0;
295 					}
296 
297 					/* Directory is encrypted */
298 					err = fscrypt_fname_disk_to_usr(inode,
299 						hash, minor_hash, &de_name, &fstr);
300 					de_name = fstr;
301 					fstr.len = save_len;
302 					if (err)
303 						goto errout;
304 					if (!dir_emit(ctx,
305 					    de_name.name, de_name.len,
306 					    le32_to_cpu(de->inode),
307 					    get_dtype(sb, de->file_type)))
308 						goto done;
309 				}
310 			}
311 			ctx->pos += ext4_rec_len_from_disk(de->rec_len,
312 						sb->s_blocksize);
313 		}
314 		if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
315 			goto done;
316 		brelse(bh);
317 		bh = NULL;
318 	}
319 done:
320 	err = 0;
321 errout:
322 	fscrypt_fname_free_buffer(&fstr);
323 	brelse(bh);
324 	return err;
325 }
326 
is_32bit_api(void)327 static inline int is_32bit_api(void)
328 {
329 #ifdef CONFIG_COMPAT
330 	return in_compat_syscall();
331 #else
332 	return (BITS_PER_LONG == 32);
333 #endif
334 }
335 
336 /*
337  * These functions convert from the major/minor hash to an f_pos
338  * value for dx directories
339  *
340  * Upper layer (for example NFS) should specify FMODE_32BITHASH or
341  * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
342  * directly on both 32-bit and 64-bit nodes, under such case, neither
343  * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
344  */
hash2pos(struct file * filp,__u32 major,__u32 minor)345 static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
346 {
347 	if ((filp->f_mode & FMODE_32BITHASH) ||
348 	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
349 		return major >> 1;
350 	else
351 		return ((__u64)(major >> 1) << 32) | (__u64)minor;
352 }
353 
pos2maj_hash(struct file * filp,loff_t pos)354 static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
355 {
356 	if ((filp->f_mode & FMODE_32BITHASH) ||
357 	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
358 		return (pos << 1) & 0xffffffff;
359 	else
360 		return ((pos >> 32) << 1) & 0xffffffff;
361 }
362 
pos2min_hash(struct file * filp,loff_t pos)363 static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
364 {
365 	if ((filp->f_mode & FMODE_32BITHASH) ||
366 	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
367 		return 0;
368 	else
369 		return pos & 0xffffffff;
370 }
371 
372 /*
373  * Return 32- or 64-bit end-of-file for dx directories
374  */
ext4_get_htree_eof(struct file * filp)375 static inline loff_t ext4_get_htree_eof(struct file *filp)
376 {
377 	if ((filp->f_mode & FMODE_32BITHASH) ||
378 	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
379 		return EXT4_HTREE_EOF_32BIT;
380 	else
381 		return EXT4_HTREE_EOF_64BIT;
382 }
383 
384 
385 /*
386  * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
387  * directories, where the "offset" is in terms of the filename hash
388  * value instead of the byte offset.
389  *
390  * Because we may return a 64-bit hash that is well beyond offset limits,
391  * we need to pass the max hash as the maximum allowable offset in
392  * the htree directory case.
393  *
394  * For non-htree, ext4_llseek already chooses the proper max offset.
395  */
ext4_dir_llseek(struct file * file,loff_t offset,int whence)396 static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
397 {
398 	struct inode *inode = file->f_mapping->host;
399 	struct dir_private_info *info = file->private_data;
400 	int dx_dir = is_dx_dir(inode);
401 	loff_t ret, htree_max = ext4_get_htree_eof(file);
402 
403 	if (likely(dx_dir))
404 		ret = generic_file_llseek_size(file, offset, whence,
405 						    htree_max, htree_max);
406 	else
407 		ret = ext4_llseek(file, offset, whence);
408 	info->cookie = inode_peek_iversion(inode) - 1;
409 	return ret;
410 }
411 
412 /*
413  * This structure holds the nodes of the red-black tree used to store
414  * the directory entry in hash order.
415  */
416 struct fname {
417 	__u32		hash;
418 	__u32		minor_hash;
419 	struct rb_node	rb_hash;
420 	struct fname	*next;
421 	__u32		inode;
422 	__u8		name_len;
423 	__u8		file_type;
424 	char		name[] __counted_by(name_len);
425 };
426 
427 /*
428  * This function implements a non-recursive way of freeing all of the
429  * nodes in the red-black tree.
430  */
free_rb_tree_fname(struct rb_root * root)431 static void free_rb_tree_fname(struct rb_root *root)
432 {
433 	struct fname *fname, *next;
434 
435 	rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
436 		while (fname) {
437 			struct fname *old = fname;
438 			fname = fname->next;
439 			kfree(old);
440 		}
441 
442 	*root = RB_ROOT;
443 }
444 
ext4_htree_init_dir_info(struct file * filp,loff_t pos)445 static void ext4_htree_init_dir_info(struct file *filp, loff_t pos)
446 {
447 	struct dir_private_info *p = filp->private_data;
448 
449 	if (is_dx_dir(file_inode(filp)) && !p->initialized) {
450 		p->curr_hash = pos2maj_hash(filp, pos);
451 		p->curr_minor_hash = pos2min_hash(filp, pos);
452 		p->initialized = true;
453 	}
454 }
455 
ext4_htree_free_dir_info(struct dir_private_info * p)456 void ext4_htree_free_dir_info(struct dir_private_info *p)
457 {
458 	free_rb_tree_fname(&p->root);
459 	kfree(p);
460 }
461 
462 /*
463  * Given a directory entry, enter it into the fname rb tree.
464  *
465  * When filename encryption is enabled, the dirent will hold the
466  * encrypted filename, while the htree will hold decrypted filename.
467  * The decrypted filename is passed in via ent_name.  parameter.
468  */
ext4_htree_store_dirent(struct file * dir_file,__u32 hash,__u32 minor_hash,struct ext4_dir_entry_2 * dirent,struct fscrypt_str * ent_name)469 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
470 			     __u32 minor_hash,
471 			    struct ext4_dir_entry_2 *dirent,
472 			    struct fscrypt_str *ent_name)
473 {
474 	struct rb_node **p, *parent = NULL;
475 	struct fname *fname, *new_fn;
476 	struct dir_private_info *info;
477 
478 	info = dir_file->private_data;
479 	p = &info->root.rb_node;
480 
481 	/* Create and allocate the fname structure */
482 	new_fn = kzalloc(struct_size(new_fn, name, ent_name->len + 1),
483 			 GFP_KERNEL);
484 	if (!new_fn)
485 		return -ENOMEM;
486 	new_fn->hash = hash;
487 	new_fn->minor_hash = minor_hash;
488 	new_fn->inode = le32_to_cpu(dirent->inode);
489 	new_fn->name_len = ent_name->len;
490 	new_fn->file_type = dirent->file_type;
491 	memcpy(new_fn->name, ent_name->name, ent_name->len);
492 
493 	while (*p) {
494 		parent = *p;
495 		fname = rb_entry(parent, struct fname, rb_hash);
496 
497 		/*
498 		 * If the hash and minor hash match up, then we put
499 		 * them on a linked list.  This rarely happens...
500 		 */
501 		if ((new_fn->hash == fname->hash) &&
502 		    (new_fn->minor_hash == fname->minor_hash)) {
503 			new_fn->next = fname->next;
504 			fname->next = new_fn;
505 			return 0;
506 		}
507 
508 		if (new_fn->hash < fname->hash)
509 			p = &(*p)->rb_left;
510 		else if (new_fn->hash > fname->hash)
511 			p = &(*p)->rb_right;
512 		else if (new_fn->minor_hash < fname->minor_hash)
513 			p = &(*p)->rb_left;
514 		else /* if (new_fn->minor_hash > fname->minor_hash) */
515 			p = &(*p)->rb_right;
516 	}
517 
518 	rb_link_node(&new_fn->rb_hash, parent, p);
519 	rb_insert_color(&new_fn->rb_hash, &info->root);
520 	return 0;
521 }
522 
523 
524 
525 /*
526  * This is a helper function for ext4_dx_readdir.  It calls filldir
527  * for all entries on the fname linked list.  (Normally there is only
528  * one entry on the linked list, unless there are 62 bit hash collisions.)
529  */
call_filldir(struct file * file,struct dir_context * ctx,struct fname * fname)530 static int call_filldir(struct file *file, struct dir_context *ctx,
531 			struct fname *fname)
532 {
533 	struct dir_private_info *info = file->private_data;
534 	struct inode *inode = file_inode(file);
535 	struct super_block *sb = inode->i_sb;
536 
537 	if (!fname) {
538 		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
539 			 "called with null fname?!?", __func__, __LINE__,
540 			 inode->i_ino, current->comm);
541 		return 0;
542 	}
543 	ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
544 	while (fname) {
545 		if (!dir_emit(ctx, fname->name,
546 				fname->name_len,
547 				fname->inode,
548 				get_dtype(sb, fname->file_type))) {
549 			info->extra_fname = fname;
550 			return 1;
551 		}
552 		fname = fname->next;
553 	}
554 	return 0;
555 }
556 
ext4_dx_readdir(struct file * file,struct dir_context * ctx)557 static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
558 {
559 	struct dir_private_info *info = file->private_data;
560 	struct inode *inode = file_inode(file);
561 	struct fname *fname;
562 	int ret = 0;
563 
564 	ext4_htree_init_dir_info(file, ctx->pos);
565 
566 	if (ctx->pos == ext4_get_htree_eof(file))
567 		return 0;	/* EOF */
568 
569 	/* Some one has messed with f_pos; reset the world */
570 	if (info->last_pos != ctx->pos) {
571 		free_rb_tree_fname(&info->root);
572 		info->curr_node = NULL;
573 		info->extra_fname = NULL;
574 		info->curr_hash = pos2maj_hash(file, ctx->pos);
575 		info->curr_minor_hash = pos2min_hash(file, ctx->pos);
576 	}
577 
578 	/*
579 	 * If there are any leftover names on the hash collision
580 	 * chain, return them first.
581 	 */
582 	if (info->extra_fname) {
583 		if (call_filldir(file, ctx, info->extra_fname))
584 			goto finished;
585 		info->extra_fname = NULL;
586 		goto next_node;
587 	} else if (!info->curr_node)
588 		info->curr_node = rb_first(&info->root);
589 
590 	while (1) {
591 		/*
592 		 * Fill the rbtree if we have no more entries,
593 		 * or the inode has changed since we last read in the
594 		 * cached entries.
595 		 */
596 		if ((!info->curr_node) ||
597 		    !inode_eq_iversion(inode, info->cookie)) {
598 			info->curr_node = NULL;
599 			free_rb_tree_fname(&info->root);
600 			info->cookie = inode_query_iversion(inode);
601 			ret = ext4_htree_fill_tree(file, info->curr_hash,
602 						   info->curr_minor_hash,
603 						   &info->next_hash);
604 			if (ret < 0)
605 				goto finished;
606 			if (ret == 0) {
607 				ctx->pos = ext4_get_htree_eof(file);
608 				break;
609 			}
610 			info->curr_node = rb_first(&info->root);
611 		}
612 
613 		fname = rb_entry(info->curr_node, struct fname, rb_hash);
614 		info->curr_hash = fname->hash;
615 		info->curr_minor_hash = fname->minor_hash;
616 		if (call_filldir(file, ctx, fname))
617 			break;
618 	next_node:
619 		info->curr_node = rb_next(info->curr_node);
620 		if (info->curr_node) {
621 			fname = rb_entry(info->curr_node, struct fname,
622 					 rb_hash);
623 			info->curr_hash = fname->hash;
624 			info->curr_minor_hash = fname->minor_hash;
625 		} else {
626 			if (info->next_hash == ~0) {
627 				ctx->pos = ext4_get_htree_eof(file);
628 				break;
629 			}
630 			info->curr_hash = info->next_hash;
631 			info->curr_minor_hash = 0;
632 		}
633 	}
634 finished:
635 	info->last_pos = ctx->pos;
636 	return ret < 0 ? ret : 0;
637 }
638 
ext4_release_dir(struct inode * inode,struct file * filp)639 static int ext4_release_dir(struct inode *inode, struct file *filp)
640 {
641 	if (filp->private_data)
642 		ext4_htree_free_dir_info(filp->private_data);
643 
644 	return 0;
645 }
646 
ext4_check_all_de(struct inode * dir,struct buffer_head * bh,void * buf,int buf_size)647 int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
648 		      int buf_size)
649 {
650 	struct ext4_dir_entry_2 *de;
651 	int rlen;
652 	unsigned int offset = 0;
653 	char *top;
654 
655 	de = buf;
656 	top = buf + buf_size;
657 	while ((char *) de < top) {
658 		if (ext4_check_dir_entry(dir, NULL, de, bh,
659 					 buf, buf_size, offset))
660 			return -EFSCORRUPTED;
661 		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
662 		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
663 		offset += rlen;
664 	}
665 	if ((char *) de > top)
666 		return -EFSCORRUPTED;
667 
668 	return 0;
669 }
670 
ext4_dir_open(struct inode * inode,struct file * file)671 static int ext4_dir_open(struct inode *inode, struct file *file)
672 {
673 	struct dir_private_info *info;
674 
675 	info = kzalloc(sizeof(*info), GFP_KERNEL);
676 	if (!info)
677 		return -ENOMEM;
678 	file->private_data = info;
679 	return 0;
680 }
681 
682 const struct file_operations ext4_dir_operations = {
683 	.open		= ext4_dir_open,
684 	.llseek		= ext4_dir_llseek,
685 	.read		= generic_read_dir,
686 	.iterate_shared	= ext4_readdir,
687 	.unlocked_ioctl = ext4_ioctl,
688 #ifdef CONFIG_COMPAT
689 	.compat_ioctl	= ext4_compat_ioctl,
690 #endif
691 	.fsync		= ext4_sync_file,
692 	.release	= ext4_release_dir,
693 };
694