?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
enic: convert to SKB paged frag API.
[linux/fpc-iii.git] / fs / ext4 / dir.c
blob164c56092e5865a99238893c5717efc60a7aea4e
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
31 static unsigned char ext4_filetype_table[] = {
32 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
33 };
34
35 static int ext4_readdir(struct file *, void *, filldir_t);
36 static int ext4_dx_readdir(struct file *filp,
37 void *dirent, filldir_t filldir);
38 static int ext4_release_dir(struct inode *inode,
39 struct file *filp);
40
41 const 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
54 static 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 */
68 int __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
111 static 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
183 revalidate:
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 }
253 out:
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 */
278 struct 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 */
293 static 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
333 static 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
345 void 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 */
354 int 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 */
416 static 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
448 static 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 }
531 finished:
532 info->last_pos = filp->f_pos;
533 return 0;
534 }
535
536 static 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 }
Linux with added FPC-III support