blob: da80368b66f0f7ca4310b03ccb59b359ff80118e [file] [log] [blame]
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/dir.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
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 *
Mingming Cao617ba132006-10-11 01:20:53 -070015 * ext4 directory handling functions
Dave Kleikampac27a0e2006-10-11 01:20:50 -070016 *
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>
Mingming Caodab291a2006-10-11 01:21:01 -070025#include <linux/jbd2.h>
Mingming Cao617ba132006-10-11 01:20:53 -070026#include <linux/ext4_fs.h>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070027#include <linux/buffer_head.h>
28#include <linux/smp_lock.h>
29#include <linux/slab.h>
30#include <linux/rbtree.h>
31
Mingming Cao617ba132006-10-11 01:20:53 -070032static unsigned char ext4_filetype_table[] = {
Dave Kleikampac27a0e2006-10-11 01:20:50 -070033 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
34};
35
Mingming Cao617ba132006-10-11 01:20:53 -070036static int ext4_readdir(struct file *, void *, filldir_t);
37static int ext4_dx_readdir(struct file * filp,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070038 void * dirent, filldir_t filldir);
Mingming Cao617ba132006-10-11 01:20:53 -070039static int ext4_release_dir (struct inode * inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070040 struct file * filp);
41
Mingming Cao617ba132006-10-11 01:20:53 -070042const struct file_operations ext4_dir_operations = {
Dave Kleikampac27a0e2006-10-11 01:20:50 -070043 .llseek = generic_file_llseek,
44 .read = generic_read_dir,
Mingming Cao617ba132006-10-11 01:20:53 -070045 .readdir = ext4_readdir, /* we take BKL. needed?*/
46 .ioctl = ext4_ioctl, /* BKL held */
Dave Kleikampac27a0e2006-10-11 01:20:50 -070047#ifdef CONFIG_COMPAT
Mingming Cao617ba132006-10-11 01:20:53 -070048 .compat_ioctl = ext4_compat_ioctl,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070049#endif
Mingming Cao617ba132006-10-11 01:20:53 -070050 .fsync = ext4_sync_file, /* BKL held */
51#ifdef CONFIG_EXT4_INDEX
52 .release = ext4_release_dir,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070053#endif
54};
55
56
57static unsigned char get_dtype(struct super_block *sb, int filetype)
58{
Mingming Cao617ba132006-10-11 01:20:53 -070059 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
60 (filetype >= EXT4_FT_MAX))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070061 return DT_UNKNOWN;
62
Mingming Cao617ba132006-10-11 01:20:53 -070063 return (ext4_filetype_table[filetype]);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070064}
65
66
Mingming Cao617ba132006-10-11 01:20:53 -070067int ext4_check_dir_entry (const char * function, struct inode * dir,
68 struct ext4_dir_entry_2 * de,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070069 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
Mingming Cao617ba132006-10-11 01:20:53 -070075 if (rlen < EXT4_DIR_REC_LEN(1))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070076 error_msg = "rec_len is smaller than minimal";
77 else if (rlen % 4 != 0)
78 error_msg = "rec_len % 4 != 0";
Mingming Cao617ba132006-10-11 01:20:53 -070079 else if (rlen < EXT4_DIR_REC_LEN(de->name_len))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070080 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) >
Mingming Cao617ba132006-10-11 01:20:53 -070084 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070085 error_msg = "inode out of bounds";
86
87 if (error_msg != NULL)
Mingming Cao617ba132006-10-11 01:20:53 -070088 ext4_error (dir->i_sb, function,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070089 "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
Mingming Cao617ba132006-10-11 01:20:53 -070097static int ext4_readdir(struct file * filp,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070098 void * dirent, filldir_t filldir)
99{
100 int error = 0;
101 unsigned long offset;
102 int i, stored;
Mingming Cao617ba132006-10-11 01:20:53 -0700103 struct ext4_dir_entry_2 *de;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700104 struct super_block *sb;
105 int err;
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800106 struct inode *inode = filp->f_path.dentry->d_inode;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700107 int ret = 0;
108
109 sb = inode->i_sb;
110
Mingming Cao617ba132006-10-11 01:20:53 -0700111#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) ||
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700115 ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
Mingming Cao617ba132006-10-11 01:20:53 -0700116 err = ext4_dx_readdir(filp, dirent, filldir);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700117 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 */
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800125 EXT4_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT4_INDEX_FL;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700126 }
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) {
Mingming Cao617ba132006-10-11 01:20:53 -0700132 unsigned long blk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700133 struct buffer_head map_bh;
134 struct buffer_head *bh = NULL;
135
136 map_bh.b_state = 0;
Alex Tomasa86c6182006-10-11 01:21:03 -0700137 err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700138 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);
Mingming Cao617ba132006-10-11 01:20:53 -0700145 bh = ext4_bread(NULL, inode, blk, 0, &err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700146 }
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) {
Mingming Cao617ba132006-10-11 01:20:53 -0700153 ext4_error (sb, "ext4_readdir",
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700154 "directory #%lu contains a hole at offset %lu",
155 inode->i_ino, (unsigned long)filp->f_pos);
Eric Sandeene6c40212006-12-06 20:36:28 -0800156 /* corrupt size? Maybe no more blocks to read */
157 if (filp->f_pos > inode->i_blocks << 9)
158 break;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700159 filp->f_pos += sb->s_blocksize - offset;
160 continue;
161 }
162
163revalidate:
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; ) {
Mingming Cao617ba132006-10-11 01:20:53 -0700170 de = (struct ext4_dir_entry_2 *)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700171 (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) <
Mingming Cao617ba132006-10-11 01:20:53 -0700179 EXT4_DIR_REC_LEN(1))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700180 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) {
Mingming Cao617ba132006-10-11 01:20:53 -0700191 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
192 if (!ext4_check_dir_entry ("ext4_readdir", inode, de,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700193 bh, offset)) {
Andrew Morton63f57932006-10-11 01:21:24 -0700194 /*
195 * On error, skip the f_pos to the next block
196 */
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700197 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 }
230out:
231 return ret;
232}
233
Mingming Cao617ba132006-10-11 01:20:53 -0700234#ifdef CONFIG_EXT4_INDEX
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700235/*
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 */
256struct 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 */
271static 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
312static 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
Mingming Cao617ba132006-10-11 01:20:53 -0700329void ext4_htree_free_dir_info(struct dir_private_info *p)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700330{
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 */
Mingming Cao617ba132006-10-11 01:20:53 -0700338int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700339 __u32 minor_hash,
Mingming Cao617ba132006-10-11 01:20:53 -0700340 struct ext4_dir_entry_2 *dirent)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700341{
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/*
Mingming Cao617ba132006-10-11 01:20:53 -0700396 * This is a helper function for ext4_dx_readdir. It calls filldir
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700397 * 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 */
400static 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;
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800405 struct inode *inode = filp->f_path.dentry->d_inode;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700406 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
Mingming Cao617ba132006-10-11 01:20:53 -0700431static int ext4_dx_readdir(struct file * filp,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700432 void * dirent, filldir_t filldir)
433{
434 struct dir_private_info *info = filp->private_data;
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800435 struct inode *inode = filp->f_path.dentry->d_inode;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700436 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
Mingming Cao617ba132006-10-11 01:20:53 -0700446 if (filp->f_pos == EXT4_HTREE_EOF)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700447 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;
Mingming Cao617ba132006-10-11 01:20:53 -0700480 ret = ext4_htree_fill_tree(filp, info->curr_hash,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700481 info->curr_minor_hash,
482 &info->next_hash);
483 if (ret < 0)
484 return ret;
485 if (ret == 0) {
Mingming Cao617ba132006-10-11 01:20:53 -0700486 filp->f_pos = EXT4_HTREE_EOF;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700487 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) {
Mingming Cao617ba132006-10-11 01:20:53 -0700501 filp->f_pos = EXT4_HTREE_EOF;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700502 break;
503 }
504 info->curr_hash = info->next_hash;
505 info->curr_minor_hash = 0;
506 }
507 }
508finished:
509 info->last_pos = filp->f_pos;
510 return 0;
511}
512
Mingming Cao617ba132006-10-11 01:20:53 -0700513static int ext4_release_dir (struct inode * inode, struct file * filp)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700514{
Andrew Morton63f57932006-10-11 01:21:24 -0700515 if (filp->private_data)
Mingming Cao617ba132006-10-11 01:20:53 -0700516 ext4_htree_free_dir_info(filp->private_data);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700517
518 return 0;
519}
520
521#endif