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Commit | Line | Data |
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ac27a0ec | 1 | /* |
617ba13b | 2 | * linux/fs/ext4/dir.c |
ac27a0ec DK |
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 | * | |
617ba13b | 15 | * ext4 directory handling functions |
ac27a0ec DK |
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> | |
dab291af | 25 | #include <linux/jbd2.h> |
617ba13b | 26 | #include <linux/ext4_fs.h> |
ac27a0ec | 27 | #include <linux/buffer_head.h> |
ac27a0ec DK |
28 | #include <linux/slab.h> |
29 | #include <linux/rbtree.h> | |
30 | ||
617ba13b | 31 | static unsigned char ext4_filetype_table[] = { |
ac27a0ec DK |
32 | DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK |
33 | }; | |
34 | ||
617ba13b MC |
35 | static int ext4_readdir(struct file *, void *, filldir_t); |
36 | static int ext4_dx_readdir(struct file * filp, | |
ac27a0ec | 37 | void * dirent, filldir_t filldir); |
617ba13b | 38 | static int ext4_release_dir (struct inode * inode, |
ac27a0ec DK |
39 | struct file * filp); |
40 | ||
617ba13b | 41 | const struct file_operations ext4_dir_operations = { |
ac27a0ec DK |
42 | .llseek = generic_file_llseek, |
43 | .read = generic_read_dir, | |
617ba13b MC |
44 | .readdir = ext4_readdir, /* we take BKL. needed?*/ |
45 | .ioctl = ext4_ioctl, /* BKL held */ | |
ac27a0ec | 46 | #ifdef CONFIG_COMPAT |
617ba13b | 47 | .compat_ioctl = ext4_compat_ioctl, |
ac27a0ec | 48 | #endif |
617ba13b MC |
49 | .fsync = ext4_sync_file, /* BKL held */ |
50 | #ifdef CONFIG_EXT4_INDEX | |
51 | .release = ext4_release_dir, | |
ac27a0ec DK |
52 | #endif |
53 | }; | |
54 | ||
55 | ||
56 | static unsigned char get_dtype(struct super_block *sb, int filetype) | |
57 | { | |
617ba13b MC |
58 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) || |
59 | (filetype >= EXT4_FT_MAX)) | |
ac27a0ec DK |
60 | return DT_UNKNOWN; |
61 | ||
617ba13b | 62 | return (ext4_filetype_table[filetype]); |
ac27a0ec DK |
63 | } |
64 | ||
65 | ||
617ba13b MC |
66 | int ext4_check_dir_entry (const char * function, struct inode * dir, |
67 | struct ext4_dir_entry_2 * de, | |
ac27a0ec DK |
68 | struct buffer_head * bh, |
69 | unsigned long offset) | |
70 | { | |
71 | const char * error_msg = NULL; | |
72 | const int rlen = le16_to_cpu(de->rec_len); | |
73 | ||
617ba13b | 74 | if (rlen < EXT4_DIR_REC_LEN(1)) |
ac27a0ec DK |
75 | error_msg = "rec_len is smaller than minimal"; |
76 | else if (rlen % 4 != 0) | |
77 | error_msg = "rec_len % 4 != 0"; | |
617ba13b | 78 | else if (rlen < EXT4_DIR_REC_LEN(de->name_len)) |
ac27a0ec DK |
79 | error_msg = "rec_len is too small for name_len"; |
80 | else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize) | |
81 | error_msg = "directory entry across blocks"; | |
82 | else if (le32_to_cpu(de->inode) > | |
617ba13b | 83 | le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)) |
ac27a0ec DK |
84 | error_msg = "inode out of bounds"; |
85 | ||
86 | if (error_msg != NULL) | |
617ba13b | 87 | ext4_error (dir->i_sb, function, |
ac27a0ec DK |
88 | "bad entry in directory #%lu: %s - " |
89 | "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", | |
90 | dir->i_ino, error_msg, offset, | |
91 | (unsigned long) le32_to_cpu(de->inode), | |
92 | rlen, de->name_len); | |
93 | return error_msg == NULL ? 1 : 0; | |
94 | } | |
95 | ||
617ba13b | 96 | static int ext4_readdir(struct file * filp, |
ac27a0ec DK |
97 | void * dirent, filldir_t filldir) |
98 | { | |
99 | int error = 0; | |
100 | unsigned long offset; | |
101 | int i, stored; | |
617ba13b | 102 | struct ext4_dir_entry_2 *de; |
ac27a0ec DK |
103 | struct super_block *sb; |
104 | int err; | |
9d549890 | 105 | struct inode *inode = filp->f_path.dentry->d_inode; |
ac27a0ec DK |
106 | int ret = 0; |
107 | ||
108 | sb = inode->i_sb; | |
109 | ||
617ba13b MC |
110 | #ifdef CONFIG_EXT4_INDEX |
111 | if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb, | |
112 | EXT4_FEATURE_COMPAT_DIR_INDEX) && | |
113 | ((EXT4_I(inode)->i_flags & EXT4_INDEX_FL) || | |
ac27a0ec | 114 | ((inode->i_size >> sb->s_blocksize_bits) == 1))) { |
617ba13b | 115 | err = ext4_dx_readdir(filp, dirent, filldir); |
ac27a0ec DK |
116 | if (err != ERR_BAD_DX_DIR) { |
117 | ret = err; | |
118 | goto out; | |
119 | } | |
120 | /* | |
121 | * We don't set the inode dirty flag since it's not | |
122 | * critical that it get flushed back to the disk. | |
123 | */ | |
9d549890 | 124 | EXT4_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT4_INDEX_FL; |
ac27a0ec DK |
125 | } |
126 | #endif | |
127 | stored = 0; | |
128 | offset = filp->f_pos & (sb->s_blocksize - 1); | |
129 | ||
130 | while (!error && !stored && filp->f_pos < inode->i_size) { | |
617ba13b | 131 | unsigned long blk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb); |
ac27a0ec DK |
132 | struct buffer_head map_bh; |
133 | struct buffer_head *bh = NULL; | |
134 | ||
135 | map_bh.b_state = 0; | |
a86c6181 | 136 | err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0); |
ac27a0ec DK |
137 | if (err > 0) { |
138 | page_cache_readahead(sb->s_bdev->bd_inode->i_mapping, | |
139 | &filp->f_ra, | |
140 | filp, | |
141 | map_bh.b_blocknr >> | |
142 | (PAGE_CACHE_SHIFT - inode->i_blkbits), | |
143 | 1); | |
617ba13b | 144 | bh = ext4_bread(NULL, inode, blk, 0, &err); |
ac27a0ec DK |
145 | } |
146 | ||
147 | /* | |
148 | * We ignore I/O errors on directories so users have a chance | |
149 | * of recovering data when there's a bad sector | |
150 | */ | |
151 | if (!bh) { | |
617ba13b | 152 | ext4_error (sb, "ext4_readdir", |
ac27a0ec DK |
153 | "directory #%lu contains a hole at offset %lu", |
154 | inode->i_ino, (unsigned long)filp->f_pos); | |
e6c40211 ES |
155 | /* corrupt size? Maybe no more blocks to read */ |
156 | if (filp->f_pos > inode->i_blocks << 9) | |
157 | break; | |
ac27a0ec DK |
158 | filp->f_pos += sb->s_blocksize - offset; |
159 | continue; | |
160 | } | |
161 | ||
162 | revalidate: | |
163 | /* If the dir block has changed since the last call to | |
164 | * readdir(2), then we might be pointing to an invalid | |
165 | * dirent right now. Scan from the start of the block | |
166 | * to make sure. */ | |
167 | if (filp->f_version != inode->i_version) { | |
168 | for (i = 0; i < sb->s_blocksize && i < offset; ) { | |
617ba13b | 169 | de = (struct ext4_dir_entry_2 *) |
ac27a0ec DK |
170 | (bh->b_data + i); |
171 | /* It's too expensive to do a full | |
172 | * dirent test each time round this | |
173 | * loop, but we do have to test at | |
174 | * least that it is non-zero. A | |
175 | * failure will be detected in the | |
176 | * dirent test below. */ | |
177 | if (le16_to_cpu(de->rec_len) < | |
617ba13b | 178 | EXT4_DIR_REC_LEN(1)) |
ac27a0ec DK |
179 | break; |
180 | i += le16_to_cpu(de->rec_len); | |
181 | } | |
182 | offset = i; | |
183 | filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1)) | |
184 | | offset; | |
185 | filp->f_version = inode->i_version; | |
186 | } | |
187 | ||
188 | while (!error && filp->f_pos < inode->i_size | |
189 | && offset < sb->s_blocksize) { | |
617ba13b MC |
190 | de = (struct ext4_dir_entry_2 *) (bh->b_data + offset); |
191 | if (!ext4_check_dir_entry ("ext4_readdir", inode, de, | |
ac27a0ec | 192 | bh, offset)) { |
63f57933 AM |
193 | /* |
194 | * On error, skip the f_pos to the next block | |
195 | */ | |
ac27a0ec DK |
196 | filp->f_pos = (filp->f_pos | |
197 | (sb->s_blocksize - 1)) + 1; | |
198 | brelse (bh); | |
199 | ret = stored; | |
200 | goto out; | |
201 | } | |
202 | offset += le16_to_cpu(de->rec_len); | |
203 | if (le32_to_cpu(de->inode)) { | |
204 | /* We might block in the next section | |
205 | * if the data destination is | |
206 | * currently swapped out. So, use a | |
207 | * version stamp to detect whether or | |
208 | * not the directory has been modified | |
209 | * during the copy operation. | |
210 | */ | |
211 | unsigned long version = filp->f_version; | |
212 | ||
213 | error = filldir(dirent, de->name, | |
214 | de->name_len, | |
215 | filp->f_pos, | |
216 | le32_to_cpu(de->inode), | |
217 | get_dtype(sb, de->file_type)); | |
218 | if (error) | |
219 | break; | |
220 | if (version != filp->f_version) | |
221 | goto revalidate; | |
222 | stored ++; | |
223 | } | |
224 | filp->f_pos += le16_to_cpu(de->rec_len); | |
225 | } | |
226 | offset = 0; | |
227 | brelse (bh); | |
228 | } | |
229 | out: | |
230 | return ret; | |
231 | } | |
232 | ||
617ba13b | 233 | #ifdef CONFIG_EXT4_INDEX |
ac27a0ec DK |
234 | /* |
235 | * These functions convert from the major/minor hash to an f_pos | |
236 | * value. | |
237 | * | |
238 | * Currently we only use major hash numer. This is unfortunate, but | |
239 | * on 32-bit machines, the same VFS interface is used for lseek and | |
240 | * llseek, so if we use the 64 bit offset, then the 32-bit versions of | |
241 | * lseek/telldir/seekdir will blow out spectacularly, and from within | |
242 | * the ext2 low-level routine, we don't know if we're being called by | |
243 | * a 64-bit version of the system call or the 32-bit version of the | |
244 | * system call. Worse yet, NFSv2 only allows for a 32-bit readdir | |
245 | * cookie. Sigh. | |
246 | */ | |
247 | #define hash2pos(major, minor) (major >> 1) | |
248 | #define pos2maj_hash(pos) ((pos << 1) & 0xffffffff) | |
249 | #define pos2min_hash(pos) (0) | |
250 | ||
251 | /* | |
252 | * This structure holds the nodes of the red-black tree used to store | |
253 | * the directory entry in hash order. | |
254 | */ | |
255 | struct fname { | |
256 | __u32 hash; | |
257 | __u32 minor_hash; | |
258 | struct rb_node rb_hash; | |
259 | struct fname *next; | |
260 | __u32 inode; | |
261 | __u8 name_len; | |
262 | __u8 file_type; | |
263 | char name[0]; | |
264 | }; | |
265 | ||
266 | /* | |
267 | * This functoin implements a non-recursive way of freeing all of the | |
268 | * nodes in the red-black tree. | |
269 | */ | |
270 | static void free_rb_tree_fname(struct rb_root *root) | |
271 | { | |
272 | struct rb_node *n = root->rb_node; | |
273 | struct rb_node *parent; | |
274 | struct fname *fname; | |
275 | ||
276 | while (n) { | |
277 | /* Do the node's children first */ | |
278 | if ((n)->rb_left) { | |
279 | n = n->rb_left; | |
280 | continue; | |
281 | } | |
282 | if (n->rb_right) { | |
283 | n = n->rb_right; | |
284 | continue; | |
285 | } | |
286 | /* | |
287 | * The node has no children; free it, and then zero | |
288 | * out parent's link to it. Finally go to the | |
289 | * beginning of the loop and try to free the parent | |
290 | * node. | |
291 | */ | |
292 | parent = rb_parent(n); | |
293 | fname = rb_entry(n, struct fname, rb_hash); | |
294 | while (fname) { | |
295 | struct fname * old = fname; | |
296 | fname = fname->next; | |
297 | kfree (old); | |
298 | } | |
299 | if (!parent) | |
300 | root->rb_node = NULL; | |
301 | else if (parent->rb_left == n) | |
302 | parent->rb_left = NULL; | |
303 | else if (parent->rb_right == n) | |
304 | parent->rb_right = NULL; | |
305 | n = parent; | |
306 | } | |
307 | root->rb_node = NULL; | |
308 | } | |
309 | ||
310 | ||
311 | static struct dir_private_info *create_dir_info(loff_t pos) | |
312 | { | |
313 | struct dir_private_info *p; | |
314 | ||
315 | p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL); | |
316 | if (!p) | |
317 | return NULL; | |
318 | p->root.rb_node = NULL; | |
319 | p->curr_node = NULL; | |
320 | p->extra_fname = NULL; | |
321 | p->last_pos = 0; | |
322 | p->curr_hash = pos2maj_hash(pos); | |
323 | p->curr_minor_hash = pos2min_hash(pos); | |
324 | p->next_hash = 0; | |
325 | return p; | |
326 | } | |
327 | ||
617ba13b | 328 | void ext4_htree_free_dir_info(struct dir_private_info *p) |
ac27a0ec DK |
329 | { |
330 | free_rb_tree_fname(&p->root); | |
331 | kfree(p); | |
332 | } | |
333 | ||
334 | /* | |
335 | * Given a directory entry, enter it into the fname rb tree. | |
336 | */ | |
617ba13b | 337 | int ext4_htree_store_dirent(struct file *dir_file, __u32 hash, |
ac27a0ec | 338 | __u32 minor_hash, |
617ba13b | 339 | struct ext4_dir_entry_2 *dirent) |
ac27a0ec DK |
340 | { |
341 | struct rb_node **p, *parent = NULL; | |
342 | struct fname * fname, *new_fn; | |
343 | struct dir_private_info *info; | |
344 | int len; | |
345 | ||
346 | info = (struct dir_private_info *) dir_file->private_data; | |
347 | p = &info->root.rb_node; | |
348 | ||
349 | /* Create and allocate the fname structure */ | |
350 | len = sizeof(struct fname) + dirent->name_len + 1; | |
351 | new_fn = kzalloc(len, GFP_KERNEL); | |
352 | if (!new_fn) | |
353 | return -ENOMEM; | |
354 | new_fn->hash = hash; | |
355 | new_fn->minor_hash = minor_hash; | |
356 | new_fn->inode = le32_to_cpu(dirent->inode); | |
357 | new_fn->name_len = dirent->name_len; | |
358 | new_fn->file_type = dirent->file_type; | |
359 | memcpy(new_fn->name, dirent->name, dirent->name_len); | |
360 | new_fn->name[dirent->name_len] = 0; | |
361 | ||
362 | while (*p) { | |
363 | parent = *p; | |
364 | fname = rb_entry(parent, struct fname, rb_hash); | |
365 | ||
366 | /* | |
367 | * If the hash and minor hash match up, then we put | |
368 | * them on a linked list. This rarely happens... | |
369 | */ | |
370 | if ((new_fn->hash == fname->hash) && | |
371 | (new_fn->minor_hash == fname->minor_hash)) { | |
372 | new_fn->next = fname->next; | |
373 | fname->next = new_fn; | |
374 | return 0; | |
375 | } | |
376 | ||
377 | if (new_fn->hash < fname->hash) | |
378 | p = &(*p)->rb_left; | |
379 | else if (new_fn->hash > fname->hash) | |
380 | p = &(*p)->rb_right; | |
381 | else if (new_fn->minor_hash < fname->minor_hash) | |
382 | p = &(*p)->rb_left; | |
383 | else /* if (new_fn->minor_hash > fname->minor_hash) */ | |
384 | p = &(*p)->rb_right; | |
385 | } | |
386 | ||
387 | rb_link_node(&new_fn->rb_hash, parent, p); | |
388 | rb_insert_color(&new_fn->rb_hash, &info->root); | |
389 | return 0; | |
390 | } | |
391 | ||
392 | ||
393 | ||
394 | /* | |
617ba13b | 395 | * This is a helper function for ext4_dx_readdir. It calls filldir |
ac27a0ec DK |
396 | * for all entres on the fname linked list. (Normally there is only |
397 | * one entry on the linked list, unless there are 62 bit hash collisions.) | |
398 | */ | |
399 | static int call_filldir(struct file * filp, void * dirent, | |
400 | filldir_t filldir, struct fname *fname) | |
401 | { | |
402 | struct dir_private_info *info = filp->private_data; | |
403 | loff_t curr_pos; | |
9d549890 | 404 | struct inode *inode = filp->f_path.dentry->d_inode; |
ac27a0ec DK |
405 | struct super_block * sb; |
406 | int error; | |
407 | ||
408 | sb = inode->i_sb; | |
409 | ||
410 | if (!fname) { | |
411 | printk("call_filldir: called with null fname?!?\n"); | |
412 | return 0; | |
413 | } | |
414 | curr_pos = hash2pos(fname->hash, fname->minor_hash); | |
415 | while (fname) { | |
416 | error = filldir(dirent, fname->name, | |
417 | fname->name_len, curr_pos, | |
418 | fname->inode, | |
419 | get_dtype(sb, fname->file_type)); | |
420 | if (error) { | |
421 | filp->f_pos = curr_pos; | |
422 | info->extra_fname = fname->next; | |
423 | return error; | |
424 | } | |
425 | fname = fname->next; | |
426 | } | |
427 | return 0; | |
428 | } | |
429 | ||
617ba13b | 430 | static int ext4_dx_readdir(struct file * filp, |
ac27a0ec DK |
431 | void * dirent, filldir_t filldir) |
432 | { | |
433 | struct dir_private_info *info = filp->private_data; | |
9d549890 | 434 | struct inode *inode = filp->f_path.dentry->d_inode; |
ac27a0ec DK |
435 | struct fname *fname; |
436 | int ret; | |
437 | ||
438 | if (!info) { | |
439 | info = create_dir_info(filp->f_pos); | |
440 | if (!info) | |
441 | return -ENOMEM; | |
442 | filp->private_data = info; | |
443 | } | |
444 | ||
617ba13b | 445 | if (filp->f_pos == EXT4_HTREE_EOF) |
ac27a0ec DK |
446 | return 0; /* EOF */ |
447 | ||
448 | /* Some one has messed with f_pos; reset the world */ | |
449 | if (info->last_pos != filp->f_pos) { | |
450 | free_rb_tree_fname(&info->root); | |
451 | info->curr_node = NULL; | |
452 | info->extra_fname = NULL; | |
453 | info->curr_hash = pos2maj_hash(filp->f_pos); | |
454 | info->curr_minor_hash = pos2min_hash(filp->f_pos); | |
455 | } | |
456 | ||
457 | /* | |
458 | * If there are any leftover names on the hash collision | |
459 | * chain, return them first. | |
460 | */ | |
461 | if (info->extra_fname && | |
462 | call_filldir(filp, dirent, filldir, info->extra_fname)) | |
463 | goto finished; | |
464 | ||
465 | if (!info->curr_node) | |
466 | info->curr_node = rb_first(&info->root); | |
467 | ||
468 | while (1) { | |
469 | /* | |
470 | * Fill the rbtree if we have no more entries, | |
471 | * or the inode has changed since we last read in the | |
472 | * cached entries. | |
473 | */ | |
474 | if ((!info->curr_node) || | |
475 | (filp->f_version != inode->i_version)) { | |
476 | info->curr_node = NULL; | |
477 | free_rb_tree_fname(&info->root); | |
478 | filp->f_version = inode->i_version; | |
617ba13b | 479 | ret = ext4_htree_fill_tree(filp, info->curr_hash, |
ac27a0ec DK |
480 | info->curr_minor_hash, |
481 | &info->next_hash); | |
482 | if (ret < 0) | |
483 | return ret; | |
484 | if (ret == 0) { | |
617ba13b | 485 | filp->f_pos = EXT4_HTREE_EOF; |
ac27a0ec DK |
486 | break; |
487 | } | |
488 | info->curr_node = rb_first(&info->root); | |
489 | } | |
490 | ||
491 | fname = rb_entry(info->curr_node, struct fname, rb_hash); | |
492 | info->curr_hash = fname->hash; | |
493 | info->curr_minor_hash = fname->minor_hash; | |
494 | if (call_filldir(filp, dirent, filldir, fname)) | |
495 | break; | |
496 | ||
497 | info->curr_node = rb_next(info->curr_node); | |
498 | if (!info->curr_node) { | |
499 | if (info->next_hash == ~0) { | |
617ba13b | 500 | filp->f_pos = EXT4_HTREE_EOF; |
ac27a0ec DK |
501 | break; |
502 | } | |
503 | info->curr_hash = info->next_hash; | |
504 | info->curr_minor_hash = 0; | |
505 | } | |
506 | } | |
507 | finished: | |
508 | info->last_pos = filp->f_pos; | |
509 | return 0; | |
510 | } | |
511 | ||
617ba13b | 512 | static int ext4_release_dir (struct inode * inode, struct file * filp) |
ac27a0ec | 513 | { |
63f57933 | 514 | if (filp->private_data) |
617ba13b | 515 | ext4_htree_free_dir_info(filp->private_data); |
ac27a0ec DK |
516 | |
517 | return 0; | |
518 | } | |
519 | ||
520 | #endif |