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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 "ext4.h"
30#include "xattr.h"
31
32static int ext4_dx_readdir(struct file *, struct dir_context *);
33
34/**
35 * Check if the given dir-inode refers to an htree-indexed directory
36 * (or a directory which could potentially get converted to use htree
37 * indexing).
38 *
39 * Return 1 if it is a dx dir, 0 if not
40 */
41static int is_dx_dir(struct inode *inode)
42{
43 struct super_block *sb = inode->i_sb;
44
45 if (ext4_has_feature_dir_index(inode->i_sb) &&
46 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
47 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
48 ext4_has_inline_data(inode)))
49 return 1;
50
51 return 0;
52}
53
54/*
55 * Return 0 if the directory entry is OK, and 1 if there is a problem
56 *
57 * Note: this is the opposite of what ext2 and ext3 historically returned...
58 *
59 * bh passed here can be an inode block or a dir data block, depending
60 * on the inode inline data flag.
61 */
62int __ext4_check_dir_entry(const char *function, unsigned int line,
63 struct inode *dir, struct file *filp,
64 struct ext4_dir_entry_2 *de,
65 struct buffer_head *bh, char *buf, int size,
66 unsigned int offset)
67{
68 const char *error_msg = NULL;
69 const int rlen = ext4_rec_len_from_disk(de->rec_len,
70 dir->i_sb->s_blocksize);
71
72 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
73 error_msg = "rec_len is smaller than minimal";
74 else if (unlikely(rlen % 4 != 0))
75 error_msg = "rec_len % 4 != 0";
76 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
77 error_msg = "rec_len is too small for name_len";
78 else if (unlikely(((char *) de - buf) + rlen > size))
79 error_msg = "directory entry across range";
80 else if (unlikely(le32_to_cpu(de->inode) >
81 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
82 error_msg = "inode out of bounds";
83 else
84 return 0;
85
86 if (filp)
87 ext4_error_file(filp, function, line, bh->b_blocknr,
88 "bad entry in directory: %s - offset=%u(%u), "
89 "inode=%u, rec_len=%d, name_len=%d",
90 error_msg, (unsigned) (offset % size),
91 offset, le32_to_cpu(de->inode),
92 rlen, de->name_len);
93 else
94 ext4_error_inode(dir, function, line, bh->b_blocknr,
95 "bad entry in directory: %s - offset=%u(%u), "
96 "inode=%u, rec_len=%d, name_len=%d",
97 error_msg, (unsigned) (offset % size),
98 offset, le32_to_cpu(de->inode),
99 rlen, de->name_len);
100
101 return 1;
102}
103
104static int ext4_readdir(struct file *file, struct dir_context *ctx)
105{
106 unsigned int offset;
107 int i;
108 struct ext4_dir_entry_2 *de;
109 int err;
110 struct inode *inode = file_inode(file);
111 struct super_block *sb = inode->i_sb;
112 struct buffer_head *bh = NULL;
113 int dir_has_error = 0;
114 struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
115
116 if (ext4_encrypted_inode(inode)) {
117 err = fscrypt_get_encryption_info(inode);
118 if (err && err != -ENOKEY)
119 return err;
120 }
121
122 if (is_dx_dir(inode)) {
123 err = ext4_dx_readdir(file, ctx);
124 if (err != ERR_BAD_DX_DIR) {
125 return err;
126 }
127 /*
128 * We don't set the inode dirty flag since it's not
129 * critical that it get flushed back to the disk.
130 */
131 ext4_clear_inode_flag(file_inode(file),
132 EXT4_INODE_INDEX);
133 }
134
135 if (ext4_has_inline_data(inode)) {
136 int has_inline_data = 1;
137 err = ext4_read_inline_dir(file, ctx,
138 &has_inline_data);
139 if (has_inline_data)
140 return err;
141 }
142
143 if (ext4_encrypted_inode(inode)) {
144 err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
145 if (err < 0)
146 return err;
147 }
148
149 offset = ctx->pos & (sb->s_blocksize - 1);
150
151 while (ctx->pos < inode->i_size) {
152 struct ext4_map_blocks map;
153
154 if (fatal_signal_pending(current)) {
155 err = -ERESTARTSYS;
156 goto errout;
157 }
158 cond_resched();
159 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
160 map.m_len = 1;
161 err = ext4_map_blocks(NULL, inode, &map, 0);
162 if (err > 0) {
163 pgoff_t index = map.m_pblk >>
164 (PAGE_SHIFT - inode->i_blkbits);
165 if (!ra_has_index(&file->f_ra, index))
166 page_cache_sync_readahead(
167 sb->s_bdev->bd_inode->i_mapping,
168 &file->f_ra, file,
169 index, 1);
170 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
171 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
172 if (IS_ERR(bh)) {
173 err = PTR_ERR(bh);
174 bh = NULL;
175 goto errout;
176 }
177 }
178
179 if (!bh) {
180 if (!dir_has_error) {
181 EXT4_ERROR_FILE(file, 0,
182 "directory contains a "
183 "hole at offset %llu",
184 (unsigned long long) ctx->pos);
185 dir_has_error = 1;
186 }
187 /* corrupt size? Maybe no more blocks to read */
188 if (ctx->pos > inode->i_blocks << 9)
189 break;
190 ctx->pos += sb->s_blocksize - offset;
191 continue;
192 }
193
194 /* Check the checksum */
195 if (!buffer_verified(bh) &&
196 !ext4_dirent_csum_verify(inode,
197 (struct ext4_dir_entry *)bh->b_data)) {
198 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
199 "at offset %llu",
200 (unsigned long long)ctx->pos);
201 ctx->pos += sb->s_blocksize - offset;
202 brelse(bh);
203 bh = NULL;
204 continue;
205 }
206 set_buffer_verified(bh);
207
208 /* If the dir block has changed since the last call to
209 * readdir(2), then we might be pointing to an invalid
210 * dirent right now. Scan from the start of the block
211 * to make sure. */
212 if (!inode_eq_iversion(inode, file->f_version)) {
213 for (i = 0; i < sb->s_blocksize && i < offset; ) {
214 de = (struct ext4_dir_entry_2 *)
215 (bh->b_data + i);
216 /* It's too expensive to do a full
217 * dirent test each time round this
218 * loop, but we do have to test at
219 * least that it is non-zero. A
220 * failure will be detected in the
221 * dirent test below. */
222 if (ext4_rec_len_from_disk(de->rec_len,
223 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
224 break;
225 i += ext4_rec_len_from_disk(de->rec_len,
226 sb->s_blocksize);
227 }
228 offset = i;
229 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
230 | offset;
231 file->f_version = inode_query_iversion(inode);
232 }
233
234 while (ctx->pos < inode->i_size
235 && offset < sb->s_blocksize) {
236 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
237 if (ext4_check_dir_entry(inode, file, de, bh,
238 bh->b_data, bh->b_size,
239 offset)) {
240 /*
241 * On error, skip to the next block
242 */
243 ctx->pos = (ctx->pos |
244 (sb->s_blocksize - 1)) + 1;
245 break;
246 }
247 offset += ext4_rec_len_from_disk(de->rec_len,
248 sb->s_blocksize);
249 if (le32_to_cpu(de->inode)) {
250 if (!ext4_encrypted_inode(inode)) {
251 if (!dir_emit(ctx, de->name,
252 de->name_len,
253 le32_to_cpu(de->inode),
254 get_dtype(sb, de->file_type)))
255 goto done;
256 } else {
257 int save_len = fstr.len;
258 struct fscrypt_str de_name =
259 FSTR_INIT(de->name,
260 de->name_len);
261
262 /* Directory is encrypted */
263 err = fscrypt_fname_disk_to_usr(inode,
264 0, 0, &de_name, &fstr);
265 de_name = fstr;
266 fstr.len = save_len;
267 if (err)
268 goto errout;
269 if (!dir_emit(ctx,
270 de_name.name, de_name.len,
271 le32_to_cpu(de->inode),
272 get_dtype(sb, de->file_type)))
273 goto done;
274 }
275 }
276 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
277 sb->s_blocksize);
278 }
279 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
280 goto done;
281 brelse(bh);
282 bh = NULL;
283 offset = 0;
284 }
285done:
286 err = 0;
287errout:
288#ifdef CONFIG_EXT4_FS_ENCRYPTION
289 fscrypt_fname_free_buffer(&fstr);
290#endif
291 brelse(bh);
292 return err;
293}
294
295static inline int is_32bit_api(void)
296{
297#ifdef CONFIG_COMPAT
298 return in_compat_syscall();
299#else
300 return (BITS_PER_LONG == 32);
301#endif
302}
303
304/*
305 * These functions convert from the major/minor hash to an f_pos
306 * value for dx directories
307 *
308 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
309 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
310 * directly on both 32-bit and 64-bit nodes, under such case, neither
311 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
312 */
313static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
314{
315 if ((filp->f_mode & FMODE_32BITHASH) ||
316 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
317 return major >> 1;
318 else
319 return ((__u64)(major >> 1) << 32) | (__u64)minor;
320}
321
322static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
323{
324 if ((filp->f_mode & FMODE_32BITHASH) ||
325 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
326 return (pos << 1) & 0xffffffff;
327 else
328 return ((pos >> 32) << 1) & 0xffffffff;
329}
330
331static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
332{
333 if ((filp->f_mode & FMODE_32BITHASH) ||
334 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
335 return 0;
336 else
337 return pos & 0xffffffff;
338}
339
340/*
341 * Return 32- or 64-bit end-of-file for dx directories
342 */
343static inline loff_t ext4_get_htree_eof(struct file *filp)
344{
345 if ((filp->f_mode & FMODE_32BITHASH) ||
346 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
347 return EXT4_HTREE_EOF_32BIT;
348 else
349 return EXT4_HTREE_EOF_64BIT;
350}
351
352
353/*
354 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
355 * directories, where the "offset" is in terms of the filename hash
356 * value instead of the byte offset.
357 *
358 * Because we may return a 64-bit hash that is well beyond offset limits,
359 * we need to pass the max hash as the maximum allowable offset in
360 * the htree directory case.
361 *
362 * For non-htree, ext4_llseek already chooses the proper max offset.
363 */
364static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
365{
366 struct inode *inode = file->f_mapping->host;
367 int dx_dir = is_dx_dir(inode);
368 loff_t ret, htree_max = ext4_get_htree_eof(file);
369
370 if (likely(dx_dir))
371 ret = generic_file_llseek_size(file, offset, whence,
372 htree_max, htree_max);
373 else
374 ret = ext4_llseek(file, offset, whence);
375 file->f_version = inode_peek_iversion(inode) - 1;
376 return ret;
377}
378
379/*
380 * This structure holds the nodes of the red-black tree used to store
381 * the directory entry in hash order.
382 */
383struct fname {
384 __u32 hash;
385 __u32 minor_hash;
386 struct rb_node rb_hash;
387 struct fname *next;
388 __u32 inode;
389 __u8 name_len;
390 __u8 file_type;
391 char name[0];
392};
393
394/*
395 * This functoin implements a non-recursive way of freeing all of the
396 * nodes in the red-black tree.
397 */
398static void free_rb_tree_fname(struct rb_root *root)
399{
400 struct fname *fname, *next;
401
402 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
403 while (fname) {
404 struct fname *old = fname;
405 fname = fname->next;
406 kfree(old);
407 }
408
409 *root = RB_ROOT;
410}
411
412
413static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
414 loff_t pos)
415{
416 struct dir_private_info *p;
417
418 p = kzalloc(sizeof(*p), GFP_KERNEL);
419 if (!p)
420 return NULL;
421 p->curr_hash = pos2maj_hash(filp, pos);
422 p->curr_minor_hash = pos2min_hash(filp, pos);
423 return p;
424}
425
426void ext4_htree_free_dir_info(struct dir_private_info *p)
427{
428 free_rb_tree_fname(&p->root);
429 kfree(p);
430}
431
432/*
433 * Given a directory entry, enter it into the fname rb tree.
434 *
435 * When filename encryption is enabled, the dirent will hold the
436 * encrypted filename, while the htree will hold decrypted filename.
437 * The decrypted filename is passed in via ent_name. parameter.
438 */
439int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
440 __u32 minor_hash,
441 struct ext4_dir_entry_2 *dirent,
442 struct fscrypt_str *ent_name)
443{
444 struct rb_node **p, *parent = NULL;
445 struct fname *fname, *new_fn;
446 struct dir_private_info *info;
447 int len;
448
449 info = dir_file->private_data;
450 p = &info->root.rb_node;
451
452 /* Create and allocate the fname structure */
453 len = sizeof(struct fname) + ent_name->len + 1;
454 new_fn = kzalloc(len, GFP_KERNEL);
455 if (!new_fn)
456 return -ENOMEM;
457 new_fn->hash = hash;
458 new_fn->minor_hash = minor_hash;
459 new_fn->inode = le32_to_cpu(dirent->inode);
460 new_fn->name_len = ent_name->len;
461 new_fn->file_type = dirent->file_type;
462 memcpy(new_fn->name, ent_name->name, ent_name->len);
463 new_fn->name[ent_name->len] = 0;
464
465 while (*p) {
466 parent = *p;
467 fname = rb_entry(parent, struct fname, rb_hash);
468
469 /*
470 * If the hash and minor hash match up, then we put
471 * them on a linked list. This rarely happens...
472 */
473 if ((new_fn->hash == fname->hash) &&
474 (new_fn->minor_hash == fname->minor_hash)) {
475 new_fn->next = fname->next;
476 fname->next = new_fn;
477 return 0;
478 }
479
480 if (new_fn->hash < fname->hash)
481 p = &(*p)->rb_left;
482 else if (new_fn->hash > fname->hash)
483 p = &(*p)->rb_right;
484 else if (new_fn->minor_hash < fname->minor_hash)
485 p = &(*p)->rb_left;
486 else /* if (new_fn->minor_hash > fname->minor_hash) */
487 p = &(*p)->rb_right;
488 }
489
490 rb_link_node(&new_fn->rb_hash, parent, p);
491 rb_insert_color(&new_fn->rb_hash, &info->root);
492 return 0;
493}
494
495
496
497/*
498 * This is a helper function for ext4_dx_readdir. It calls filldir
499 * for all entres on the fname linked list. (Normally there is only
500 * one entry on the linked list, unless there are 62 bit hash collisions.)
501 */
502static int call_filldir(struct file *file, struct dir_context *ctx,
503 struct fname *fname)
504{
505 struct dir_private_info *info = file->private_data;
506 struct inode *inode = file_inode(file);
507 struct super_block *sb = inode->i_sb;
508
509 if (!fname) {
510 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
511 "called with null fname?!?", __func__, __LINE__,
512 inode->i_ino, current->comm);
513 return 0;
514 }
515 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
516 while (fname) {
517 if (!dir_emit(ctx, fname->name,
518 fname->name_len,
519 fname->inode,
520 get_dtype(sb, fname->file_type))) {
521 info->extra_fname = fname;
522 return 1;
523 }
524 fname = fname->next;
525 }
526 return 0;
527}
528
529static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
530{
531 struct dir_private_info *info = file->private_data;
532 struct inode *inode = file_inode(file);
533 struct fname *fname;
534 int ret;
535
536 if (!info) {
537 info = ext4_htree_create_dir_info(file, ctx->pos);
538 if (!info)
539 return -ENOMEM;
540 file->private_data = info;
541 }
542
543 if (ctx->pos == ext4_get_htree_eof(file))
544 return 0; /* EOF */
545
546 /* Some one has messed with f_pos; reset the world */
547 if (info->last_pos != ctx->pos) {
548 free_rb_tree_fname(&info->root);
549 info->curr_node = NULL;
550 info->extra_fname = NULL;
551 info->curr_hash = pos2maj_hash(file, ctx->pos);
552 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
553 }
554
555 /*
556 * If there are any leftover names on the hash collision
557 * chain, return them first.
558 */
559 if (info->extra_fname) {
560 if (call_filldir(file, ctx, info->extra_fname))
561 goto finished;
562 info->extra_fname = NULL;
563 goto next_node;
564 } else if (!info->curr_node)
565 info->curr_node = rb_first(&info->root);
566
567 while (1) {
568 /*
569 * Fill the rbtree if we have no more entries,
570 * or the inode has changed since we last read in the
571 * cached entries.
572 */
573 if ((!info->curr_node) ||
574 !inode_eq_iversion(inode, file->f_version)) {
575 info->curr_node = NULL;
576 free_rb_tree_fname(&info->root);
577 file->f_version = inode_query_iversion(inode);
578 ret = ext4_htree_fill_tree(file, info->curr_hash,
579 info->curr_minor_hash,
580 &info->next_hash);
581 if (ret < 0)
582 return ret;
583 if (ret == 0) {
584 ctx->pos = ext4_get_htree_eof(file);
585 break;
586 }
587 info->curr_node = rb_first(&info->root);
588 }
589
590 fname = rb_entry(info->curr_node, struct fname, rb_hash);
591 info->curr_hash = fname->hash;
592 info->curr_minor_hash = fname->minor_hash;
593 if (call_filldir(file, ctx, fname))
594 break;
595 next_node:
596 info->curr_node = rb_next(info->curr_node);
597 if (info->curr_node) {
598 fname = rb_entry(info->curr_node, struct fname,
599 rb_hash);
600 info->curr_hash = fname->hash;
601 info->curr_minor_hash = fname->minor_hash;
602 } else {
603 if (info->next_hash == ~0) {
604 ctx->pos = ext4_get_htree_eof(file);
605 break;
606 }
607 info->curr_hash = info->next_hash;
608 info->curr_minor_hash = 0;
609 }
610 }
611finished:
612 info->last_pos = ctx->pos;
613 return 0;
614}
615
616static int ext4_dir_open(struct inode * inode, struct file * filp)
617{
618 if (ext4_encrypted_inode(inode))
619 return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
620 return 0;
621}
622
623static int ext4_release_dir(struct inode *inode, struct file *filp)
624{
625 if (filp->private_data)
626 ext4_htree_free_dir_info(filp->private_data);
627
628 return 0;
629}
630
631int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
632 int buf_size)
633{
634 struct ext4_dir_entry_2 *de;
635 int rlen;
636 unsigned int offset = 0;
637 char *top;
638
639 de = (struct ext4_dir_entry_2 *)buf;
640 top = buf + buf_size;
641 while ((char *) de < top) {
642 if (ext4_check_dir_entry(dir, NULL, de, bh,
643 buf, buf_size, offset))
644 return -EFSCORRUPTED;
645 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
646 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
647 offset += rlen;
648 }
649 if ((char *) de > top)
650 return -EFSCORRUPTED;
651
652 return 0;
653}
654
655const struct file_operations ext4_dir_operations = {
656 .llseek = ext4_dir_llseek,
657 .read = generic_read_dir,
658 .iterate_shared = ext4_readdir,
659 .unlocked_ioctl = ext4_ioctl,
660#ifdef CONFIG_COMPAT
661 .compat_ioctl = ext4_compat_ioctl,
662#endif
663 .fsync = ext4_sync_file,
664 .open = ext4_dir_open,
665 .release = ext4_release_dir,
666};
1/*
2 * linux/fs/ext4/dir.c
3 *
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)
8 *
9 * from
10 *
11 * linux/fs/minix/dir.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext4 directory handling functions
16 *
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 *
20 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
21 *
22 */
23
24#include <linux/fs.h>
25#include <linux/jbd2.h>
26#include <linux/buffer_head.h>
27#include <linux/slab.h>
28#include <linux/rbtree.h>
29#include "ext4.h"
30
31static unsigned char ext4_filetype_table[] = {
32 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
33};
34
35static int ext4_dx_readdir(struct file *filp,
36 void *dirent, filldir_t filldir);
37
38static unsigned char get_dtype(struct super_block *sb, int filetype)
39{
40 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
41 (filetype >= EXT4_FT_MAX))
42 return DT_UNKNOWN;
43
44 return (ext4_filetype_table[filetype]);
45}
46
47/**
48 * Check if the given dir-inode refers to an htree-indexed directory
49 * (or a directory which chould potentially get coverted to use htree
50 * indexing).
51 *
52 * Return 1 if it is a dx dir, 0 if not
53 */
54static int is_dx_dir(struct inode *inode)
55{
56 struct super_block *sb = inode->i_sb;
57
58 if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
59 EXT4_FEATURE_COMPAT_DIR_INDEX) &&
60 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
61 ((inode->i_size >> sb->s_blocksize_bits) == 1)))
62 return 1;
63
64 return 0;
65}
66
67/*
68 * Return 0 if the directory entry is OK, and 1 if there is a problem
69 *
70 * Note: this is the opposite of what ext2 and ext3 historically returned...
71 */
72int __ext4_check_dir_entry(const char *function, unsigned int line,
73 struct inode *dir, struct file *filp,
74 struct ext4_dir_entry_2 *de,
75 struct buffer_head *bh,
76 unsigned int offset)
77{
78 const char *error_msg = NULL;
79 const int rlen = ext4_rec_len_from_disk(de->rec_len,
80 dir->i_sb->s_blocksize);
81
82 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
83 error_msg = "rec_len is smaller than minimal";
84 else if (unlikely(rlen % 4 != 0))
85 error_msg = "rec_len % 4 != 0";
86 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
87 error_msg = "rec_len is too small for name_len";
88 else if (unlikely(((char *) de - bh->b_data) + rlen >
89 dir->i_sb->s_blocksize))
90 error_msg = "directory entry across blocks";
91 else if (unlikely(le32_to_cpu(de->inode) >
92 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
93 error_msg = "inode out of bounds";
94 else
95 return 0;
96
97 if (filp)
98 ext4_error_file(filp, function, line, bh->b_blocknr,
99 "bad entry in directory: %s - offset=%u(%u), "
100 "inode=%u, rec_len=%d, name_len=%d",
101 error_msg, (unsigned) (offset % bh->b_size),
102 offset, le32_to_cpu(de->inode),
103 rlen, de->name_len);
104 else
105 ext4_error_inode(dir, function, line, bh->b_blocknr,
106 "bad entry in directory: %s - offset=%u(%u), "
107 "inode=%u, rec_len=%d, name_len=%d",
108 error_msg, (unsigned) (offset % bh->b_size),
109 offset, le32_to_cpu(de->inode),
110 rlen, de->name_len);
111
112 return 1;
113}
114
115static int ext4_readdir(struct file *filp,
116 void *dirent, filldir_t filldir)
117{
118 int error = 0;
119 unsigned int offset;
120 int i, stored;
121 struct ext4_dir_entry_2 *de;
122 int err;
123 struct inode *inode = filp->f_path.dentry->d_inode;
124 struct super_block *sb = inode->i_sb;
125 int ret = 0;
126 int dir_has_error = 0;
127
128 if (is_dx_dir(inode)) {
129 err = ext4_dx_readdir(filp, dirent, filldir);
130 if (err != ERR_BAD_DX_DIR) {
131 ret = err;
132 goto out;
133 }
134 /*
135 * We don't set the inode dirty flag since it's not
136 * critical that it get flushed back to the disk.
137 */
138 ext4_clear_inode_flag(filp->f_path.dentry->d_inode,
139 EXT4_INODE_INDEX);
140 }
141 stored = 0;
142 offset = filp->f_pos & (sb->s_blocksize - 1);
143
144 while (!error && !stored && filp->f_pos < inode->i_size) {
145 struct ext4_map_blocks map;
146 struct buffer_head *bh = NULL;
147
148 map.m_lblk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
149 map.m_len = 1;
150 err = ext4_map_blocks(NULL, inode, &map, 0);
151 if (err > 0) {
152 pgoff_t index = map.m_pblk >>
153 (PAGE_CACHE_SHIFT - inode->i_blkbits);
154 if (!ra_has_index(&filp->f_ra, index))
155 page_cache_sync_readahead(
156 sb->s_bdev->bd_inode->i_mapping,
157 &filp->f_ra, filp,
158 index, 1);
159 filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
160 bh = ext4_bread(NULL, inode, map.m_lblk, 0, &err);
161 }
162
163 /*
164 * We ignore I/O errors on directories so users have a chance
165 * of recovering data when there's a bad sector
166 */
167 if (!bh) {
168 if (!dir_has_error) {
169 EXT4_ERROR_FILE(filp, 0,
170 "directory contains a "
171 "hole at offset %llu",
172 (unsigned long long) filp->f_pos);
173 dir_has_error = 1;
174 }
175 /* corrupt size? Maybe no more blocks to read */
176 if (filp->f_pos > inode->i_blocks << 9)
177 break;
178 filp->f_pos += sb->s_blocksize - offset;
179 continue;
180 }
181
182 /* Check the checksum */
183 if (!buffer_verified(bh) &&
184 !ext4_dirent_csum_verify(inode,
185 (struct ext4_dir_entry *)bh->b_data)) {
186 EXT4_ERROR_FILE(filp, 0, "directory fails checksum "
187 "at offset %llu",
188 (unsigned long long)filp->f_pos);
189 filp->f_pos += sb->s_blocksize - offset;
190 continue;
191 }
192 set_buffer_verified(bh);
193
194revalidate:
195 /* If the dir block has changed since the last call to
196 * readdir(2), then we might be pointing to an invalid
197 * dirent right now. Scan from the start of the block
198 * to make sure. */
199 if (filp->f_version != inode->i_version) {
200 for (i = 0; i < sb->s_blocksize && i < offset; ) {
201 de = (struct ext4_dir_entry_2 *)
202 (bh->b_data + i);
203 /* It's too expensive to do a full
204 * dirent test each time round this
205 * loop, but we do have to test at
206 * least that it is non-zero. A
207 * failure will be detected in the
208 * dirent test below. */
209 if (ext4_rec_len_from_disk(de->rec_len,
210 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
211 break;
212 i += ext4_rec_len_from_disk(de->rec_len,
213 sb->s_blocksize);
214 }
215 offset = i;
216 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
217 | offset;
218 filp->f_version = inode->i_version;
219 }
220
221 while (!error && filp->f_pos < inode->i_size
222 && offset < sb->s_blocksize) {
223 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
224 if (ext4_check_dir_entry(inode, filp, de,
225 bh, offset)) {
226 /*
227 * On error, skip the f_pos to the next block
228 */
229 filp->f_pos = (filp->f_pos |
230 (sb->s_blocksize - 1)) + 1;
231 brelse(bh);
232 ret = stored;
233 goto out;
234 }
235 offset += ext4_rec_len_from_disk(de->rec_len,
236 sb->s_blocksize);
237 if (le32_to_cpu(de->inode)) {
238 /* We might block in the next section
239 * if the data destination is
240 * currently swapped out. So, use a
241 * version stamp to detect whether or
242 * not the directory has been modified
243 * during the copy operation.
244 */
245 u64 version = filp->f_version;
246
247 error = filldir(dirent, de->name,
248 de->name_len,
249 filp->f_pos,
250 le32_to_cpu(de->inode),
251 get_dtype(sb, de->file_type));
252 if (error)
253 break;
254 if (version != filp->f_version)
255 goto revalidate;
256 stored++;
257 }
258 filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
259 sb->s_blocksize);
260 }
261 offset = 0;
262 brelse(bh);
263 }
264out:
265 return ret;
266}
267
268static inline int is_32bit_api(void)
269{
270#ifdef CONFIG_COMPAT
271 return is_compat_task();
272#else
273 return (BITS_PER_LONG == 32);
274#endif
275}
276
277/*
278 * These functions convert from the major/minor hash to an f_pos
279 * value for dx directories
280 *
281 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
282 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
283 * directly on both 32-bit and 64-bit nodes, under such case, neither
284 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
285 */
286static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
287{
288 if ((filp->f_mode & FMODE_32BITHASH) ||
289 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
290 return major >> 1;
291 else
292 return ((__u64)(major >> 1) << 32) | (__u64)minor;
293}
294
295static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
296{
297 if ((filp->f_mode & FMODE_32BITHASH) ||
298 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
299 return (pos << 1) & 0xffffffff;
300 else
301 return ((pos >> 32) << 1) & 0xffffffff;
302}
303
304static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
305{
306 if ((filp->f_mode & FMODE_32BITHASH) ||
307 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
308 return 0;
309 else
310 return pos & 0xffffffff;
311}
312
313/*
314 * Return 32- or 64-bit end-of-file for dx directories
315 */
316static inline loff_t ext4_get_htree_eof(struct file *filp)
317{
318 if ((filp->f_mode & FMODE_32BITHASH) ||
319 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
320 return EXT4_HTREE_EOF_32BIT;
321 else
322 return EXT4_HTREE_EOF_64BIT;
323}
324
325
326/*
327 * ext4_dir_llseek() based on generic_file_llseek() to handle both
328 * non-htree and htree directories, where the "offset" is in terms
329 * of the filename hash value instead of the byte offset.
330 *
331 * NOTE: offsets obtained *before* ext4_set_inode_flag(dir, EXT4_INODE_INDEX)
332 * will be invalid once the directory was converted into a dx directory
333 */
334loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin)
335{
336 struct inode *inode = file->f_mapping->host;
337 loff_t ret = -EINVAL;
338 int dx_dir = is_dx_dir(inode);
339
340 mutex_lock(&inode->i_mutex);
341
342 /* NOTE: relative offsets with dx directories might not work
343 * as expected, as it is difficult to figure out the
344 * correct offset between dx hashes */
345
346 switch (origin) {
347 case SEEK_END:
348 if (unlikely(offset > 0))
349 goto out_err; /* not supported for directories */
350
351 /* so only negative offsets are left, does that have a
352 * meaning for directories at all? */
353 if (dx_dir)
354 offset += ext4_get_htree_eof(file);
355 else
356 offset += inode->i_size;
357 break;
358 case SEEK_CUR:
359 /*
360 * Here we special-case the lseek(fd, 0, SEEK_CUR)
361 * position-querying operation. Avoid rewriting the "same"
362 * f_pos value back to the file because a concurrent read(),
363 * write() or lseek() might have altered it
364 */
365 if (offset == 0) {
366 offset = file->f_pos;
367 goto out_ok;
368 }
369
370 offset += file->f_pos;
371 break;
372 }
373
374 if (unlikely(offset < 0))
375 goto out_err;
376
377 if (!dx_dir) {
378 if (offset > inode->i_sb->s_maxbytes)
379 goto out_err;
380 } else if (offset > ext4_get_htree_eof(file))
381 goto out_err;
382
383 /* Special lock needed here? */
384 if (offset != file->f_pos) {
385 file->f_pos = offset;
386 file->f_version = 0;
387 }
388
389out_ok:
390 ret = offset;
391out_err:
392 mutex_unlock(&inode->i_mutex);
393
394 return ret;
395}
396
397/*
398 * This structure holds the nodes of the red-black tree used to store
399 * the directory entry in hash order.
400 */
401struct fname {
402 __u32 hash;
403 __u32 minor_hash;
404 struct rb_node rb_hash;
405 struct fname *next;
406 __u32 inode;
407 __u8 name_len;
408 __u8 file_type;
409 char name[0];
410};
411
412/*
413 * This functoin implements a non-recursive way of freeing all of the
414 * nodes in the red-black tree.
415 */
416static void free_rb_tree_fname(struct rb_root *root)
417{
418 struct rb_node *n = root->rb_node;
419 struct rb_node *parent;
420 struct fname *fname;
421
422 while (n) {
423 /* Do the node's children first */
424 if (n->rb_left) {
425 n = n->rb_left;
426 continue;
427 }
428 if (n->rb_right) {
429 n = n->rb_right;
430 continue;
431 }
432 /*
433 * The node has no children; free it, and then zero
434 * out parent's link to it. Finally go to the
435 * beginning of the loop and try to free the parent
436 * node.
437 */
438 parent = rb_parent(n);
439 fname = rb_entry(n, struct fname, rb_hash);
440 while (fname) {
441 struct fname *old = fname;
442 fname = fname->next;
443 kfree(old);
444 }
445 if (!parent)
446 *root = RB_ROOT;
447 else if (parent->rb_left == n)
448 parent->rb_left = NULL;
449 else if (parent->rb_right == n)
450 parent->rb_right = NULL;
451 n = parent;
452 }
453}
454
455
456static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
457 loff_t pos)
458{
459 struct dir_private_info *p;
460
461 p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
462 if (!p)
463 return NULL;
464 p->curr_hash = pos2maj_hash(filp, pos);
465 p->curr_minor_hash = pos2min_hash(filp, pos);
466 return p;
467}
468
469void ext4_htree_free_dir_info(struct dir_private_info *p)
470{
471 free_rb_tree_fname(&p->root);
472 kfree(p);
473}
474
475/*
476 * Given a directory entry, enter it into the fname rb tree.
477 */
478int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
479 __u32 minor_hash,
480 struct ext4_dir_entry_2 *dirent)
481{
482 struct rb_node **p, *parent = NULL;
483 struct fname *fname, *new_fn;
484 struct dir_private_info *info;
485 int len;
486
487 info = dir_file->private_data;
488 p = &info->root.rb_node;
489
490 /* Create and allocate the fname structure */
491 len = sizeof(struct fname) + dirent->name_len + 1;
492 new_fn = kzalloc(len, GFP_KERNEL);
493 if (!new_fn)
494 return -ENOMEM;
495 new_fn->hash = hash;
496 new_fn->minor_hash = minor_hash;
497 new_fn->inode = le32_to_cpu(dirent->inode);
498 new_fn->name_len = dirent->name_len;
499 new_fn->file_type = dirent->file_type;
500 memcpy(new_fn->name, dirent->name, dirent->name_len);
501 new_fn->name[dirent->name_len] = 0;
502
503 while (*p) {
504 parent = *p;
505 fname = rb_entry(parent, struct fname, rb_hash);
506
507 /*
508 * If the hash and minor hash match up, then we put
509 * them on a linked list. This rarely happens...
510 */
511 if ((new_fn->hash == fname->hash) &&
512 (new_fn->minor_hash == fname->minor_hash)) {
513 new_fn->next = fname->next;
514 fname->next = new_fn;
515 return 0;
516 }
517
518 if (new_fn->hash < fname->hash)
519 p = &(*p)->rb_left;
520 else if (new_fn->hash > fname->hash)
521 p = &(*p)->rb_right;
522 else if (new_fn->minor_hash < fname->minor_hash)
523 p = &(*p)->rb_left;
524 else /* if (new_fn->minor_hash > fname->minor_hash) */
525 p = &(*p)->rb_right;
526 }
527
528 rb_link_node(&new_fn->rb_hash, parent, p);
529 rb_insert_color(&new_fn->rb_hash, &info->root);
530 return 0;
531}
532
533
534
535/*
536 * This is a helper function for ext4_dx_readdir. It calls filldir
537 * for all entres on the fname linked list. (Normally there is only
538 * one entry on the linked list, unless there are 62 bit hash collisions.)
539 */
540static int call_filldir(struct file *filp, void *dirent,
541 filldir_t filldir, struct fname *fname)
542{
543 struct dir_private_info *info = filp->private_data;
544 loff_t curr_pos;
545 struct inode *inode = filp->f_path.dentry->d_inode;
546 struct super_block *sb;
547 int error;
548
549 sb = inode->i_sb;
550
551 if (!fname) {
552 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
553 "called with null fname?!?", __func__, __LINE__,
554 inode->i_ino, current->comm);
555 return 0;
556 }
557 curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
558 while (fname) {
559 error = filldir(dirent, fname->name,
560 fname->name_len, curr_pos,
561 fname->inode,
562 get_dtype(sb, fname->file_type));
563 if (error) {
564 filp->f_pos = curr_pos;
565 info->extra_fname = fname;
566 return error;
567 }
568 fname = fname->next;
569 }
570 return 0;
571}
572
573static int ext4_dx_readdir(struct file *filp,
574 void *dirent, filldir_t filldir)
575{
576 struct dir_private_info *info = filp->private_data;
577 struct inode *inode = filp->f_path.dentry->d_inode;
578 struct fname *fname;
579 int ret;
580
581 if (!info) {
582 info = ext4_htree_create_dir_info(filp, filp->f_pos);
583 if (!info)
584 return -ENOMEM;
585 filp->private_data = info;
586 }
587
588 if (filp->f_pos == ext4_get_htree_eof(filp))
589 return 0; /* EOF */
590
591 /* Some one has messed with f_pos; reset the world */
592 if (info->last_pos != filp->f_pos) {
593 free_rb_tree_fname(&info->root);
594 info->curr_node = NULL;
595 info->extra_fname = NULL;
596 info->curr_hash = pos2maj_hash(filp, filp->f_pos);
597 info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
598 }
599
600 /*
601 * If there are any leftover names on the hash collision
602 * chain, return them first.
603 */
604 if (info->extra_fname) {
605 if (call_filldir(filp, dirent, filldir, info->extra_fname))
606 goto finished;
607 info->extra_fname = NULL;
608 goto next_node;
609 } else if (!info->curr_node)
610 info->curr_node = rb_first(&info->root);
611
612 while (1) {
613 /*
614 * Fill the rbtree if we have no more entries,
615 * or the inode has changed since we last read in the
616 * cached entries.
617 */
618 if ((!info->curr_node) ||
619 (filp->f_version != inode->i_version)) {
620 info->curr_node = NULL;
621 free_rb_tree_fname(&info->root);
622 filp->f_version = inode->i_version;
623 ret = ext4_htree_fill_tree(filp, info->curr_hash,
624 info->curr_minor_hash,
625 &info->next_hash);
626 if (ret < 0)
627 return ret;
628 if (ret == 0) {
629 filp->f_pos = ext4_get_htree_eof(filp);
630 break;
631 }
632 info->curr_node = rb_first(&info->root);
633 }
634
635 fname = rb_entry(info->curr_node, struct fname, rb_hash);
636 info->curr_hash = fname->hash;
637 info->curr_minor_hash = fname->minor_hash;
638 if (call_filldir(filp, dirent, filldir, fname))
639 break;
640 next_node:
641 info->curr_node = rb_next(info->curr_node);
642 if (info->curr_node) {
643 fname = rb_entry(info->curr_node, struct fname,
644 rb_hash);
645 info->curr_hash = fname->hash;
646 info->curr_minor_hash = fname->minor_hash;
647 } else {
648 if (info->next_hash == ~0) {
649 filp->f_pos = ext4_get_htree_eof(filp);
650 break;
651 }
652 info->curr_hash = info->next_hash;
653 info->curr_minor_hash = 0;
654 }
655 }
656finished:
657 info->last_pos = filp->f_pos;
658 return 0;
659}
660
661static int ext4_release_dir(struct inode *inode, struct file *filp)
662{
663 if (filp->private_data)
664 ext4_htree_free_dir_info(filp->private_data);
665
666 return 0;
667}
668
669const struct file_operations ext4_dir_operations = {
670 .llseek = ext4_dir_llseek,
671 .read = generic_read_dir,
672 .readdir = ext4_readdir,
673 .unlocked_ioctl = ext4_ioctl,
674#ifdef CONFIG_COMPAT
675 .compat_ioctl = ext4_compat_ioctl,
676#endif
677 .fsync = ext4_sync_file,
678 .release = ext4_release_dir,
679};