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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};
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_readdir(struct file *, void *, filldir_t);
36static int ext4_dx_readdir(struct file *filp,
37 void *dirent, filldir_t filldir);
38static int ext4_release_dir(struct inode *inode,
39 struct file *filp);
40
41const struct file_operations ext4_dir_operations = {
42 .llseek = ext4_llseek,
43 .read = generic_read_dir,
44 .readdir = ext4_readdir, /* we take BKL. needed?*/
45 .unlocked_ioctl = ext4_ioctl,
46#ifdef CONFIG_COMPAT
47 .compat_ioctl = ext4_compat_ioctl,
48#endif
49 .fsync = ext4_sync_file,
50 .release = ext4_release_dir,
51};
52
53
54static unsigned char get_dtype(struct super_block *sb, int filetype)
55{
56 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
57 (filetype >= EXT4_FT_MAX))
58 return DT_UNKNOWN;
59
60 return (ext4_filetype_table[filetype]);
61}
62
63/*
64 * Return 0 if the directory entry is OK, and 1 if there is a problem
65 *
66 * Note: this is the opposite of what ext2 and ext3 historically returned...
67 */
68int __ext4_check_dir_entry(const char *function, unsigned int line,
69 struct inode *dir, struct file *filp,
70 struct ext4_dir_entry_2 *de,
71 struct buffer_head *bh,
72 unsigned int offset)
73{
74 const char *error_msg = NULL;
75 const int rlen = ext4_rec_len_from_disk(de->rec_len,
76 dir->i_sb->s_blocksize);
77
78 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
79 error_msg = "rec_len is smaller than minimal";
80 else if (unlikely(rlen % 4 != 0))
81 error_msg = "rec_len % 4 != 0";
82 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
83 error_msg = "rec_len is too small for name_len";
84 else if (unlikely(((char *) de - bh->b_data) + rlen >
85 dir->i_sb->s_blocksize))
86 error_msg = "directory entry across blocks";
87 else if (unlikely(le32_to_cpu(de->inode) >
88 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
89 error_msg = "inode out of bounds";
90 else
91 return 0;
92
93 if (filp)
94 ext4_error_file(filp, function, line, bh ? bh->b_blocknr : 0,
95 "bad entry in directory: %s - offset=%u(%u), "
96 "inode=%u, rec_len=%d, name_len=%d",
97 error_msg, (unsigned) (offset%bh->b_size),
98 offset, le32_to_cpu(de->inode),
99 rlen, de->name_len);
100 else
101 ext4_error_inode(dir, function, line, bh ? bh->b_blocknr : 0,
102 "bad entry in directory: %s - offset=%u(%u), "
103 "inode=%u, rec_len=%d, name_len=%d",
104 error_msg, (unsigned) (offset%bh->b_size),
105 offset, le32_to_cpu(de->inode),
106 rlen, de->name_len);
107
108 return 1;
109}
110
111static int ext4_readdir(struct file *filp,
112 void *dirent, filldir_t filldir)
113{
114 int error = 0;
115 unsigned int offset;
116 int i, stored;
117 struct ext4_dir_entry_2 *de;
118 struct super_block *sb;
119 int err;
120 struct inode *inode = filp->f_path.dentry->d_inode;
121 int ret = 0;
122 int dir_has_error = 0;
123
124 sb = inode->i_sb;
125
126 if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
127 EXT4_FEATURE_COMPAT_DIR_INDEX) &&
128 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
129 ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
130 err = ext4_dx_readdir(filp, dirent, filldir);
131 if (err != ERR_BAD_DX_DIR) {
132 ret = err;
133 goto out;
134 }
135 /*
136 * We don't set the inode dirty flag since it's not
137 * critical that it get flushed back to the disk.
138 */
139 ext4_clear_inode_flag(filp->f_path.dentry->d_inode,
140 EXT4_INODE_INDEX);
141 }
142 stored = 0;
143 offset = filp->f_pos & (sb->s_blocksize - 1);
144
145 while (!error && !stored && filp->f_pos < inode->i_size) {
146 struct ext4_map_blocks map;
147 struct buffer_head *bh = NULL;
148
149 map.m_lblk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
150 map.m_len = 1;
151 err = ext4_map_blocks(NULL, inode, &map, 0);
152 if (err > 0) {
153 pgoff_t index = map.m_pblk >>
154 (PAGE_CACHE_SHIFT - inode->i_blkbits);
155 if (!ra_has_index(&filp->f_ra, index))
156 page_cache_sync_readahead(
157 sb->s_bdev->bd_inode->i_mapping,
158 &filp->f_ra, filp,
159 index, 1);
160 filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
161 bh = ext4_bread(NULL, inode, map.m_lblk, 0, &err);
162 }
163
164 /*
165 * We ignore I/O errors on directories so users have a chance
166 * of recovering data when there's a bad sector
167 */
168 if (!bh) {
169 if (!dir_has_error) {
170 EXT4_ERROR_FILE(filp, 0,
171 "directory contains a "
172 "hole at offset %llu",
173 (unsigned long long) filp->f_pos);
174 dir_has_error = 1;
175 }
176 /* corrupt size? Maybe no more blocks to read */
177 if (filp->f_pos > inode->i_blocks << 9)
178 break;
179 filp->f_pos += sb->s_blocksize - offset;
180 continue;
181 }
182
183revalidate:
184 /* If the dir block has changed since the last call to
185 * readdir(2), then we might be pointing to an invalid
186 * dirent right now. Scan from the start of the block
187 * to make sure. */
188 if (filp->f_version != inode->i_version) {
189 for (i = 0; i < sb->s_blocksize && i < offset; ) {
190 de = (struct ext4_dir_entry_2 *)
191 (bh->b_data + i);
192 /* It's too expensive to do a full
193 * dirent test each time round this
194 * loop, but we do have to test at
195 * least that it is non-zero. A
196 * failure will be detected in the
197 * dirent test below. */
198 if (ext4_rec_len_from_disk(de->rec_len,
199 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
200 break;
201 i += ext4_rec_len_from_disk(de->rec_len,
202 sb->s_blocksize);
203 }
204 offset = i;
205 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
206 | offset;
207 filp->f_version = inode->i_version;
208 }
209
210 while (!error && filp->f_pos < inode->i_size
211 && offset < sb->s_blocksize) {
212 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
213 if (ext4_check_dir_entry(inode, filp, de,
214 bh, offset)) {
215 /*
216 * On error, skip the f_pos to the next block
217 */
218 filp->f_pos = (filp->f_pos |
219 (sb->s_blocksize - 1)) + 1;
220 brelse(bh);
221 ret = stored;
222 goto out;
223 }
224 offset += ext4_rec_len_from_disk(de->rec_len,
225 sb->s_blocksize);
226 if (le32_to_cpu(de->inode)) {
227 /* We might block in the next section
228 * if the data destination is
229 * currently swapped out. So, use a
230 * version stamp to detect whether or
231 * not the directory has been modified
232 * during the copy operation.
233 */
234 u64 version = filp->f_version;
235
236 error = filldir(dirent, de->name,
237 de->name_len,
238 filp->f_pos,
239 le32_to_cpu(de->inode),
240 get_dtype(sb, de->file_type));
241 if (error)
242 break;
243 if (version != filp->f_version)
244 goto revalidate;
245 stored++;
246 }
247 filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
248 sb->s_blocksize);
249 }
250 offset = 0;
251 brelse(bh);
252 }
253out:
254 return ret;
255}
256
257/*
258 * These functions convert from the major/minor hash to an f_pos
259 * value.
260 *
261 * Currently we only use major hash numer. This is unfortunate, but
262 * on 32-bit machines, the same VFS interface is used for lseek and
263 * llseek, so if we use the 64 bit offset, then the 32-bit versions of
264 * lseek/telldir/seekdir will blow out spectacularly, and from within
265 * the ext2 low-level routine, we don't know if we're being called by
266 * a 64-bit version of the system call or the 32-bit version of the
267 * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
268 * cookie. Sigh.
269 */
270#define hash2pos(major, minor) (major >> 1)
271#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
272#define pos2min_hash(pos) (0)
273
274/*
275 * This structure holds the nodes of the red-black tree used to store
276 * the directory entry in hash order.
277 */
278struct fname {
279 __u32 hash;
280 __u32 minor_hash;
281 struct rb_node rb_hash;
282 struct fname *next;
283 __u32 inode;
284 __u8 name_len;
285 __u8 file_type;
286 char name[0];
287};
288
289/*
290 * This functoin implements a non-recursive way of freeing all of the
291 * nodes in the red-black tree.
292 */
293static void free_rb_tree_fname(struct rb_root *root)
294{
295 struct rb_node *n = root->rb_node;
296 struct rb_node *parent;
297 struct fname *fname;
298
299 while (n) {
300 /* Do the node's children first */
301 if (n->rb_left) {
302 n = n->rb_left;
303 continue;
304 }
305 if (n->rb_right) {
306 n = n->rb_right;
307 continue;
308 }
309 /*
310 * The node has no children; free it, and then zero
311 * out parent's link to it. Finally go to the
312 * beginning of the loop and try to free the parent
313 * node.
314 */
315 parent = rb_parent(n);
316 fname = rb_entry(n, struct fname, rb_hash);
317 while (fname) {
318 struct fname *old = fname;
319 fname = fname->next;
320 kfree(old);
321 }
322 if (!parent)
323 *root = RB_ROOT;
324 else if (parent->rb_left == n)
325 parent->rb_left = NULL;
326 else if (parent->rb_right == n)
327 parent->rb_right = NULL;
328 n = parent;
329 }
330}
331
332
333static struct dir_private_info *ext4_htree_create_dir_info(loff_t pos)
334{
335 struct dir_private_info *p;
336
337 p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
338 if (!p)
339 return NULL;
340 p->curr_hash = pos2maj_hash(pos);
341 p->curr_minor_hash = pos2min_hash(pos);
342 return p;
343}
344
345void ext4_htree_free_dir_info(struct dir_private_info *p)
346{
347 free_rb_tree_fname(&p->root);
348 kfree(p);
349}
350
351/*
352 * Given a directory entry, enter it into the fname rb tree.
353 */
354int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
355 __u32 minor_hash,
356 struct ext4_dir_entry_2 *dirent)
357{
358 struct rb_node **p, *parent = NULL;
359 struct fname *fname, *new_fn;
360 struct dir_private_info *info;
361 int len;
362
363 info = dir_file->private_data;
364 p = &info->root.rb_node;
365
366 /* Create and allocate the fname structure */
367 len = sizeof(struct fname) + dirent->name_len + 1;
368 new_fn = kzalloc(len, GFP_KERNEL);
369 if (!new_fn)
370 return -ENOMEM;
371 new_fn->hash = hash;
372 new_fn->minor_hash = minor_hash;
373 new_fn->inode = le32_to_cpu(dirent->inode);
374 new_fn->name_len = dirent->name_len;
375 new_fn->file_type = dirent->file_type;
376 memcpy(new_fn->name, dirent->name, dirent->name_len);
377 new_fn->name[dirent->name_len] = 0;
378
379 while (*p) {
380 parent = *p;
381 fname = rb_entry(parent, struct fname, rb_hash);
382
383 /*
384 * If the hash and minor hash match up, then we put
385 * them on a linked list. This rarely happens...
386 */
387 if ((new_fn->hash == fname->hash) &&
388 (new_fn->minor_hash == fname->minor_hash)) {
389 new_fn->next = fname->next;
390 fname->next = new_fn;
391 return 0;
392 }
393
394 if (new_fn->hash < fname->hash)
395 p = &(*p)->rb_left;
396 else if (new_fn->hash > fname->hash)
397 p = &(*p)->rb_right;
398 else if (new_fn->minor_hash < fname->minor_hash)
399 p = &(*p)->rb_left;
400 else /* if (new_fn->minor_hash > fname->minor_hash) */
401 p = &(*p)->rb_right;
402 }
403
404 rb_link_node(&new_fn->rb_hash, parent, p);
405 rb_insert_color(&new_fn->rb_hash, &info->root);
406 return 0;
407}
408
409
410
411/*
412 * This is a helper function for ext4_dx_readdir. It calls filldir
413 * for all entres on the fname linked list. (Normally there is only
414 * one entry on the linked list, unless there are 62 bit hash collisions.)
415 */
416static int call_filldir(struct file *filp, void *dirent,
417 filldir_t filldir, struct fname *fname)
418{
419 struct dir_private_info *info = filp->private_data;
420 loff_t curr_pos;
421 struct inode *inode = filp->f_path.dentry->d_inode;
422 struct super_block *sb;
423 int error;
424
425 sb = inode->i_sb;
426
427 if (!fname) {
428 printk(KERN_ERR "EXT4-fs: call_filldir: called with "
429 "null fname?!?\n");
430 return 0;
431 }
432 curr_pos = hash2pos(fname->hash, fname->minor_hash);
433 while (fname) {
434 error = filldir(dirent, fname->name,
435 fname->name_len, curr_pos,
436 fname->inode,
437 get_dtype(sb, fname->file_type));
438 if (error) {
439 filp->f_pos = curr_pos;
440 info->extra_fname = fname;
441 return error;
442 }
443 fname = fname->next;
444 }
445 return 0;
446}
447
448static int ext4_dx_readdir(struct file *filp,
449 void *dirent, filldir_t filldir)
450{
451 struct dir_private_info *info = filp->private_data;
452 struct inode *inode = filp->f_path.dentry->d_inode;
453 struct fname *fname;
454 int ret;
455
456 if (!info) {
457 info = ext4_htree_create_dir_info(filp->f_pos);
458 if (!info)
459 return -ENOMEM;
460 filp->private_data = info;
461 }
462
463 if (filp->f_pos == EXT4_HTREE_EOF)
464 return 0; /* EOF */
465
466 /* Some one has messed with f_pos; reset the world */
467 if (info->last_pos != filp->f_pos) {
468 free_rb_tree_fname(&info->root);
469 info->curr_node = NULL;
470 info->extra_fname = NULL;
471 info->curr_hash = pos2maj_hash(filp->f_pos);
472 info->curr_minor_hash = pos2min_hash(filp->f_pos);
473 }
474
475 /*
476 * If there are any leftover names on the hash collision
477 * chain, return them first.
478 */
479 if (info->extra_fname) {
480 if (call_filldir(filp, dirent, filldir, info->extra_fname))
481 goto finished;
482 info->extra_fname = NULL;
483 goto next_node;
484 } else if (!info->curr_node)
485 info->curr_node = rb_first(&info->root);
486
487 while (1) {
488 /*
489 * Fill the rbtree if we have no more entries,
490 * or the inode has changed since we last read in the
491 * cached entries.
492 */
493 if ((!info->curr_node) ||
494 (filp->f_version != inode->i_version)) {
495 info->curr_node = NULL;
496 free_rb_tree_fname(&info->root);
497 filp->f_version = inode->i_version;
498 ret = ext4_htree_fill_tree(filp, info->curr_hash,
499 info->curr_minor_hash,
500 &info->next_hash);
501 if (ret < 0)
502 return ret;
503 if (ret == 0) {
504 filp->f_pos = EXT4_HTREE_EOF;
505 break;
506 }
507 info->curr_node = rb_first(&info->root);
508 }
509
510 fname = rb_entry(info->curr_node, struct fname, rb_hash);
511 info->curr_hash = fname->hash;
512 info->curr_minor_hash = fname->minor_hash;
513 if (call_filldir(filp, dirent, filldir, fname))
514 break;
515 next_node:
516 info->curr_node = rb_next(info->curr_node);
517 if (info->curr_node) {
518 fname = rb_entry(info->curr_node, struct fname,
519 rb_hash);
520 info->curr_hash = fname->hash;
521 info->curr_minor_hash = fname->minor_hash;
522 } else {
523 if (info->next_hash == ~0) {
524 filp->f_pos = EXT4_HTREE_EOF;
525 break;
526 }
527 info->curr_hash = info->next_hash;
528 info->curr_minor_hash = 0;
529 }
530 }
531finished:
532 info->last_pos = filp->f_pos;
533 return 0;
534}
535
536static int ext4_release_dir(struct inode *inode, struct file *filp)
537{
538 if (filp->private_data)
539 ext4_htree_free_dir_info(filp->private_data);
540
541 return 0;
542}