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