blob: 3ab01c04e00c55fd07470a7de9a85d1cbf398815 [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>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070028#include <linux/slab.h>
29#include <linux/rbtree.h>
30
Mingming Cao617ba132006-10-11 01:20:53 -070031static unsigned char ext4_filetype_table[] = {
Dave Kleikampac27a0e2006-10-11 01:20:50 -070032 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
33};
34
Mingming Cao617ba132006-10-11 01:20:53 -070035static int ext4_readdir(struct file *, void *, filldir_t);
36static int ext4_dx_readdir(struct file * filp,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070037 void * dirent, filldir_t filldir);
Mingming Cao617ba132006-10-11 01:20:53 -070038static int ext4_release_dir (struct inode * inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070039 struct file * filp);
40
Mingming Cao617ba132006-10-11 01:20:53 -070041const struct file_operations ext4_dir_operations = {
Dave Kleikampac27a0e2006-10-11 01:20:50 -070042 .llseek = generic_file_llseek,
43 .read = generic_read_dir,
Mingming Cao617ba132006-10-11 01:20:53 -070044 .readdir = ext4_readdir, /* we take BKL. needed?*/
45 .ioctl = ext4_ioctl, /* BKL held */
Dave Kleikampac27a0e2006-10-11 01:20:50 -070046#ifdef CONFIG_COMPAT
Mingming Cao617ba132006-10-11 01:20:53 -070047 .compat_ioctl = ext4_compat_ioctl,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070048#endif
Mingming Cao617ba132006-10-11 01:20:53 -070049 .fsync = ext4_sync_file, /* BKL held */
50#ifdef CONFIG_EXT4_INDEX
51 .release = ext4_release_dir,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070052#endif
53};
54
55
56static unsigned char get_dtype(struct super_block *sb, int filetype)
57{
Mingming Cao617ba132006-10-11 01:20:53 -070058 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
59 (filetype >= EXT4_FT_MAX))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070060 return DT_UNKNOWN;
61
Mingming Cao617ba132006-10-11 01:20:53 -070062 return (ext4_filetype_table[filetype]);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070063}
64
65
Mingming Cao617ba132006-10-11 01:20:53 -070066int ext4_check_dir_entry (const char * function, struct inode * dir,
67 struct ext4_dir_entry_2 * de,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070068 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
Mingming Cao617ba132006-10-11 01:20:53 -070074 if (rlen < EXT4_DIR_REC_LEN(1))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070075 error_msg = "rec_len is smaller than minimal";
76 else if (rlen % 4 != 0)
77 error_msg = "rec_len % 4 != 0";
Mingming Cao617ba132006-10-11 01:20:53 -070078 else if (rlen < EXT4_DIR_REC_LEN(de->name_len))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070079 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) >
Mingming Cao617ba132006-10-11 01:20:53 -070083 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070084 error_msg = "inode out of bounds";
85
86 if (error_msg != NULL)
Mingming Cao617ba132006-10-11 01:20:53 -070087 ext4_error (dir->i_sb, function,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070088 "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
Mingming Cao617ba132006-10-11 01:20:53 -070096static int ext4_readdir(struct file * filp,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070097 void * dirent, filldir_t filldir)
98{
99 int error = 0;
100 unsigned long offset;
101 int i, stored;
Mingming Cao617ba132006-10-11 01:20:53 -0700102 struct ext4_dir_entry_2 *de;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700103 struct super_block *sb;
104 int err;
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800105 struct inode *inode = filp->f_path.dentry->d_inode;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700106 int ret = 0;
107
108 sb = inode->i_sb;
109
Mingming Cao617ba132006-10-11 01:20:53 -0700110#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) ||
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700114 ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
Mingming Cao617ba132006-10-11 01:20:53 -0700115 err = ext4_dx_readdir(filp, dirent, filldir);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700116 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 */
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800124 EXT4_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT4_INDEX_FL;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700125 }
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) {
Mingming Cao617ba132006-10-11 01:20:53 -0700131 unsigned long blk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700132 struct buffer_head map_bh;
133 struct buffer_head *bh = NULL;
134
135 map_bh.b_state = 0;
Alex Tomasa86c6182006-10-11 01:21:03 -0700136 err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700137 if (err > 0) {
Fengguang Wudc7868f2007-07-19 01:48:04 -0700138 pgoff_t index = map_bh.b_blocknr >>
139 (PAGE_CACHE_SHIFT - inode->i_blkbits);
140 if (!ra_has_index(&filp->f_ra, index))
Rusty Russellcf914a72007-07-19 01:48:08 -0700141 page_cache_sync_readahead(
Fengguang Wudc7868f2007-07-19 01:48:04 -0700142 sb->s_bdev->bd_inode->i_mapping,
143 &filp->f_ra, filp,
Rusty Russellcf914a72007-07-19 01:48:08 -0700144 index, 1);
Fengguang Wudc7868f2007-07-19 01:48:04 -0700145 filp->f_ra.prev_index = index;
Mingming Cao617ba132006-10-11 01:20:53 -0700146 bh = ext4_bread(NULL, inode, blk, 0, &err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700147 }
148
149 /*
150 * We ignore I/O errors on directories so users have a chance
151 * of recovering data when there's a bad sector
152 */
153 if (!bh) {
Mingming Cao617ba132006-10-11 01:20:53 -0700154 ext4_error (sb, "ext4_readdir",
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700155 "directory #%lu contains a hole at offset %lu",
156 inode->i_ino, (unsigned long)filp->f_pos);
Eric Sandeene6c40212006-12-06 20:36:28 -0800157 /* corrupt size? Maybe no more blocks to read */
158 if (filp->f_pos > inode->i_blocks << 9)
159 break;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700160 filp->f_pos += sb->s_blocksize - offset;
161 continue;
162 }
163
164revalidate:
165 /* If the dir block has changed since the last call to
166 * readdir(2), then we might be pointing to an invalid
167 * dirent right now. Scan from the start of the block
168 * to make sure. */
169 if (filp->f_version != inode->i_version) {
170 for (i = 0; i < sb->s_blocksize && i < offset; ) {
Mingming Cao617ba132006-10-11 01:20:53 -0700171 de = (struct ext4_dir_entry_2 *)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700172 (bh->b_data + i);
173 /* It's too expensive to do a full
174 * dirent test each time round this
175 * loop, but we do have to test at
176 * least that it is non-zero. A
177 * failure will be detected in the
178 * dirent test below. */
179 if (le16_to_cpu(de->rec_len) <
Mingming Cao617ba132006-10-11 01:20:53 -0700180 EXT4_DIR_REC_LEN(1))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700181 break;
182 i += le16_to_cpu(de->rec_len);
183 }
184 offset = i;
185 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
186 | offset;
187 filp->f_version = inode->i_version;
188 }
189
190 while (!error && filp->f_pos < inode->i_size
191 && offset < sb->s_blocksize) {
Mingming Cao617ba132006-10-11 01:20:53 -0700192 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
193 if (!ext4_check_dir_entry ("ext4_readdir", inode, de,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700194 bh, offset)) {
Andrew Morton63f57932006-10-11 01:21:24 -0700195 /*
196 * On error, skip the f_pos to the next block
197 */
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700198 filp->f_pos = (filp->f_pos |
199 (sb->s_blocksize - 1)) + 1;
200 brelse (bh);
201 ret = stored;
202 goto out;
203 }
204 offset += le16_to_cpu(de->rec_len);
205 if (le32_to_cpu(de->inode)) {
206 /* We might block in the next section
207 * if the data destination is
208 * currently swapped out. So, use a
209 * version stamp to detect whether or
210 * not the directory has been modified
211 * during the copy operation.
212 */
213 unsigned long version = filp->f_version;
214
215 error = filldir(dirent, de->name,
216 de->name_len,
217 filp->f_pos,
218 le32_to_cpu(de->inode),
219 get_dtype(sb, de->file_type));
220 if (error)
221 break;
222 if (version != filp->f_version)
223 goto revalidate;
224 stored ++;
225 }
226 filp->f_pos += le16_to_cpu(de->rec_len);
227 }
228 offset = 0;
229 brelse (bh);
230 }
231out:
232 return ret;
233}
234
Mingming Cao617ba132006-10-11 01:20:53 -0700235#ifdef CONFIG_EXT4_INDEX
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700236/*
237 * These functions convert from the major/minor hash to an f_pos
238 * value.
239 *
240 * Currently we only use major hash numer. This is unfortunate, but
241 * on 32-bit machines, the same VFS interface is used for lseek and
242 * llseek, so if we use the 64 bit offset, then the 32-bit versions of
243 * lseek/telldir/seekdir will blow out spectacularly, and from within
244 * the ext2 low-level routine, we don't know if we're being called by
245 * a 64-bit version of the system call or the 32-bit version of the
246 * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
247 * cookie. Sigh.
248 */
249#define hash2pos(major, minor) (major >> 1)
250#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
251#define pos2min_hash(pos) (0)
252
253/*
254 * This structure holds the nodes of the red-black tree used to store
255 * the directory entry in hash order.
256 */
257struct fname {
258 __u32 hash;
259 __u32 minor_hash;
260 struct rb_node rb_hash;
261 struct fname *next;
262 __u32 inode;
263 __u8 name_len;
264 __u8 file_type;
265 char name[0];
266};
267
268/*
269 * This functoin implements a non-recursive way of freeing all of the
270 * nodes in the red-black tree.
271 */
272static void free_rb_tree_fname(struct rb_root *root)
273{
274 struct rb_node *n = root->rb_node;
275 struct rb_node *parent;
276 struct fname *fname;
277
278 while (n) {
279 /* Do the node's children first */
280 if ((n)->rb_left) {
281 n = n->rb_left;
282 continue;
283 }
284 if (n->rb_right) {
285 n = n->rb_right;
286 continue;
287 }
288 /*
289 * The node has no children; free it, and then zero
290 * out parent's link to it. Finally go to the
291 * beginning of the loop and try to free the parent
292 * node.
293 */
294 parent = rb_parent(n);
295 fname = rb_entry(n, struct fname, rb_hash);
296 while (fname) {
297 struct fname * old = fname;
298 fname = fname->next;
299 kfree (old);
300 }
301 if (!parent)
302 root->rb_node = NULL;
303 else if (parent->rb_left == n)
304 parent->rb_left = NULL;
305 else if (parent->rb_right == n)
306 parent->rb_right = NULL;
307 n = parent;
308 }
309 root->rb_node = NULL;
310}
311
312
313static struct dir_private_info *create_dir_info(loff_t pos)
314{
315 struct dir_private_info *p;
316
317 p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
318 if (!p)
319 return NULL;
320 p->root.rb_node = NULL;
321 p->curr_node = NULL;
322 p->extra_fname = NULL;
323 p->last_pos = 0;
324 p->curr_hash = pos2maj_hash(pos);
325 p->curr_minor_hash = pos2min_hash(pos);
326 p->next_hash = 0;
327 return p;
328}
329
Mingming Cao617ba132006-10-11 01:20:53 -0700330void ext4_htree_free_dir_info(struct dir_private_info *p)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700331{
332 free_rb_tree_fname(&p->root);
333 kfree(p);
334}
335
336/*
337 * Given a directory entry, enter it into the fname rb tree.
338 */
Mingming Cao617ba132006-10-11 01:20:53 -0700339int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700340 __u32 minor_hash,
Mingming Cao617ba132006-10-11 01:20:53 -0700341 struct ext4_dir_entry_2 *dirent)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700342{
343 struct rb_node **p, *parent = NULL;
344 struct fname * fname, *new_fn;
345 struct dir_private_info *info;
346 int len;
347
348 info = (struct dir_private_info *) dir_file->private_data;
349 p = &info->root.rb_node;
350
351 /* Create and allocate the fname structure */
352 len = sizeof(struct fname) + dirent->name_len + 1;
353 new_fn = kzalloc(len, GFP_KERNEL);
354 if (!new_fn)
355 return -ENOMEM;
356 new_fn->hash = hash;
357 new_fn->minor_hash = minor_hash;
358 new_fn->inode = le32_to_cpu(dirent->inode);
359 new_fn->name_len = dirent->name_len;
360 new_fn->file_type = dirent->file_type;
361 memcpy(new_fn->name, dirent->name, dirent->name_len);
362 new_fn->name[dirent->name_len] = 0;
363
364 while (*p) {
365 parent = *p;
366 fname = rb_entry(parent, struct fname, rb_hash);
367
368 /*
369 * If the hash and minor hash match up, then we put
370 * them on a linked list. This rarely happens...
371 */
372 if ((new_fn->hash == fname->hash) &&
373 (new_fn->minor_hash == fname->minor_hash)) {
374 new_fn->next = fname->next;
375 fname->next = new_fn;
376 return 0;
377 }
378
379 if (new_fn->hash < fname->hash)
380 p = &(*p)->rb_left;
381 else if (new_fn->hash > fname->hash)
382 p = &(*p)->rb_right;
383 else if (new_fn->minor_hash < fname->minor_hash)
384 p = &(*p)->rb_left;
385 else /* if (new_fn->minor_hash > fname->minor_hash) */
386 p = &(*p)->rb_right;
387 }
388
389 rb_link_node(&new_fn->rb_hash, parent, p);
390 rb_insert_color(&new_fn->rb_hash, &info->root);
391 return 0;
392}
393
394
395
396/*
Mingming Cao617ba132006-10-11 01:20:53 -0700397 * This is a helper function for ext4_dx_readdir. It calls filldir
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700398 * for all entres on the fname linked list. (Normally there is only
399 * one entry on the linked list, unless there are 62 bit hash collisions.)
400 */
401static int call_filldir(struct file * filp, void * dirent,
402 filldir_t filldir, struct fname *fname)
403{
404 struct dir_private_info *info = filp->private_data;
405 loff_t curr_pos;
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800406 struct inode *inode = filp->f_path.dentry->d_inode;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700407 struct super_block * sb;
408 int error;
409
410 sb = inode->i_sb;
411
412 if (!fname) {
413 printk("call_filldir: called with null fname?!?\n");
414 return 0;
415 }
416 curr_pos = hash2pos(fname->hash, fname->minor_hash);
417 while (fname) {
418 error = filldir(dirent, fname->name,
419 fname->name_len, curr_pos,
420 fname->inode,
421 get_dtype(sb, fname->file_type));
422 if (error) {
423 filp->f_pos = curr_pos;
424 info->extra_fname = fname->next;
425 return error;
426 }
427 fname = fname->next;
428 }
429 return 0;
430}
431
Mingming Cao617ba132006-10-11 01:20:53 -0700432static int ext4_dx_readdir(struct file * filp,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700433 void * dirent, filldir_t filldir)
434{
435 struct dir_private_info *info = filp->private_data;
Josef "Jeff" Sipek9d549892006-12-08 02:36:38 -0800436 struct inode *inode = filp->f_path.dentry->d_inode;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700437 struct fname *fname;
438 int ret;
439
440 if (!info) {
441 info = create_dir_info(filp->f_pos);
442 if (!info)
443 return -ENOMEM;
444 filp->private_data = info;
445 }
446
Mingming Cao617ba132006-10-11 01:20:53 -0700447 if (filp->f_pos == EXT4_HTREE_EOF)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700448 return 0; /* EOF */
449
450 /* Some one has messed with f_pos; reset the world */
451 if (info->last_pos != filp->f_pos) {
452 free_rb_tree_fname(&info->root);
453 info->curr_node = NULL;
454 info->extra_fname = NULL;
455 info->curr_hash = pos2maj_hash(filp->f_pos);
456 info->curr_minor_hash = pos2min_hash(filp->f_pos);
457 }
458
459 /*
460 * If there are any leftover names on the hash collision
461 * chain, return them first.
462 */
463 if (info->extra_fname &&
464 call_filldir(filp, dirent, filldir, info->extra_fname))
465 goto finished;
466
467 if (!info->curr_node)
468 info->curr_node = rb_first(&info->root);
469
470 while (1) {
471 /*
472 * Fill the rbtree if we have no more entries,
473 * or the inode has changed since we last read in the
474 * cached entries.
475 */
476 if ((!info->curr_node) ||
477 (filp->f_version != inode->i_version)) {
478 info->curr_node = NULL;
479 free_rb_tree_fname(&info->root);
480 filp->f_version = inode->i_version;
Mingming Cao617ba132006-10-11 01:20:53 -0700481 ret = ext4_htree_fill_tree(filp, info->curr_hash,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700482 info->curr_minor_hash,
483 &info->next_hash);
484 if (ret < 0)
485 return ret;
486 if (ret == 0) {
Mingming Cao617ba132006-10-11 01:20:53 -0700487 filp->f_pos = EXT4_HTREE_EOF;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700488 break;
489 }
490 info->curr_node = rb_first(&info->root);
491 }
492
493 fname = rb_entry(info->curr_node, struct fname, rb_hash);
494 info->curr_hash = fname->hash;
495 info->curr_minor_hash = fname->minor_hash;
496 if (call_filldir(filp, dirent, filldir, fname))
497 break;
498
499 info->curr_node = rb_next(info->curr_node);
500 if (!info->curr_node) {
501 if (info->next_hash == ~0) {
Mingming Cao617ba132006-10-11 01:20:53 -0700502 filp->f_pos = EXT4_HTREE_EOF;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700503 break;
504 }
505 info->curr_hash = info->next_hash;
506 info->curr_minor_hash = 0;
507 }
508 }
509finished:
510 info->last_pos = filp->f_pos;
511 return 0;
512}
513
Mingming Cao617ba132006-10-11 01:20:53 -0700514static int ext4_release_dir (struct inode * inode, struct file * filp)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700515{
Andrew Morton63f57932006-10-11 01:21:24 -0700516 if (filp->private_data)
Mingming Cao617ba132006-10-11 01:20:53 -0700517 ext4_htree_free_dir_info(filp->private_data);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700518
519 return 0;
520}
521
522#endif