ext3: remove #ifdef CONFIG_EXT3_INDEX
[linux-2.6.git] / fs / ext3 / dir.c
1 /*
2  *  linux/fs/ext3/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  *  ext3 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/jbd.h>
26 #include <linux/ext3_fs.h>
27 #include <linux/buffer_head.h>
28 #include <linux/slab.h>
29 #include <linux/rbtree.h>
30
31 static unsigned char ext3_filetype_table[] = {
32         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
33 };
34
35 static int ext3_readdir(struct file *, void *, filldir_t);
36 static int ext3_dx_readdir(struct file * filp,
37                            void * dirent, filldir_t filldir);
38 static int ext3_release_dir (struct inode * inode,
39                                 struct file * filp);
40
41 const struct file_operations ext3_dir_operations = {
42         .llseek         = generic_file_llseek,
43         .read           = generic_read_dir,
44         .readdir        = ext3_readdir,         /* we take BKL. needed?*/
45         .ioctl          = ext3_ioctl,           /* BKL held */
46 #ifdef CONFIG_COMPAT
47         .compat_ioctl   = ext3_compat_ioctl,
48 #endif
49         .fsync          = ext3_sync_file,       /* BKL held */
50         .release        = ext3_release_dir,
51 };
52
53
54 static unsigned char get_dtype(struct super_block *sb, int filetype)
55 {
56         if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) ||
57             (filetype >= EXT3_FT_MAX))
58                 return DT_UNKNOWN;
59
60         return (ext3_filetype_table[filetype]);
61 }
62
63
64 int ext3_check_dir_entry (const char * function, struct inode * dir,
65                           struct ext3_dir_entry_2 * de,
66                           struct buffer_head * bh,
67                           unsigned long offset)
68 {
69         const char * error_msg = NULL;
70         const int rlen = le16_to_cpu(de->rec_len);
71
72         if (rlen < EXT3_DIR_REC_LEN(1))
73                 error_msg = "rec_len is smaller than minimal";
74         else if (rlen % 4 != 0)
75                 error_msg = "rec_len % 4 != 0";
76         else if (rlen < EXT3_DIR_REC_LEN(de->name_len))
77                 error_msg = "rec_len is too small for name_len";
78         else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
79                 error_msg = "directory entry across blocks";
80         else if (le32_to_cpu(de->inode) >
81                         le32_to_cpu(EXT3_SB(dir->i_sb)->s_es->s_inodes_count))
82                 error_msg = "inode out of bounds";
83
84         if (error_msg != NULL)
85                 ext3_error (dir->i_sb, function,
86                         "bad entry in directory #%lu: %s - "
87                         "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
88                         dir->i_ino, error_msg, offset,
89                         (unsigned long) le32_to_cpu(de->inode),
90                         rlen, de->name_len);
91         return error_msg == NULL ? 1 : 0;
92 }
93
94 static int ext3_readdir(struct file * filp,
95                          void * dirent, filldir_t filldir)
96 {
97         int error = 0;
98         unsigned long offset;
99         int i, stored;
100         struct ext3_dir_entry_2 *de;
101         struct super_block *sb;
102         int err;
103         struct inode *inode = filp->f_path.dentry->d_inode;
104         int ret = 0;
105
106         sb = inode->i_sb;
107
108         if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
109                                     EXT3_FEATURE_COMPAT_DIR_INDEX) &&
110             ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
111              ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
112                 err = ext3_dx_readdir(filp, dirent, filldir);
113                 if (err != ERR_BAD_DX_DIR) {
114                         ret = err;
115                         goto out;
116                 }
117                 /*
118                  * We don't set the inode dirty flag since it's not
119                  * critical that it get flushed back to the disk.
120                  */
121                 EXT3_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT3_INDEX_FL;
122         }
123         stored = 0;
124         offset = filp->f_pos & (sb->s_blocksize - 1);
125
126         while (!error && !stored && filp->f_pos < inode->i_size) {
127                 unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb);
128                 struct buffer_head map_bh;
129                 struct buffer_head *bh = NULL;
130
131                 map_bh.b_state = 0;
132                 err = ext3_get_blocks_handle(NULL, inode, blk, 1,
133                                                 &map_bh, 0, 0);
134                 if (err > 0) {
135                         pgoff_t index = map_bh.b_blocknr >>
136                                         (PAGE_CACHE_SHIFT - inode->i_blkbits);
137                         if (!ra_has_index(&filp->f_ra, index))
138                                 page_cache_sync_readahead(
139                                         sb->s_bdev->bd_inode->i_mapping,
140                                         &filp->f_ra, filp,
141                                         index, 1);
142                         filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
143                         bh = ext3_bread(NULL, inode, blk, 0, &err);
144                 }
145
146                 /*
147                  * We ignore I/O errors on directories so users have a chance
148                  * of recovering data when there's a bad sector
149                  */
150                 if (!bh) {
151                         ext3_error (sb, "ext3_readdir",
152                                 "directory #%lu contains a hole at offset %lu",
153                                 inode->i_ino, (unsigned long)filp->f_pos);
154                         /* corrupt size?  Maybe no more blocks to read */
155                         if (filp->f_pos > inode->i_blocks << 9)
156                                 break;
157                         filp->f_pos += sb->s_blocksize - offset;
158                         continue;
159                 }
160
161 revalidate:
162                 /* If the dir block has changed since the last call to
163                  * readdir(2), then we might be pointing to an invalid
164                  * dirent right now.  Scan from the start of the block
165                  * to make sure. */
166                 if (filp->f_version != inode->i_version) {
167                         for (i = 0; i < sb->s_blocksize && i < offset; ) {
168                                 de = (struct ext3_dir_entry_2 *)
169                                         (bh->b_data + i);
170                                 /* It's too expensive to do a full
171                                  * dirent test each time round this
172                                  * loop, but we do have to test at
173                                  * least that it is non-zero.  A
174                                  * failure will be detected in the
175                                  * dirent test below. */
176                                 if (le16_to_cpu(de->rec_len) <
177                                                 EXT3_DIR_REC_LEN(1))
178                                         break;
179                                 i += le16_to_cpu(de->rec_len);
180                         }
181                         offset = i;
182                         filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
183                                 | offset;
184                         filp->f_version = inode->i_version;
185                 }
186
187                 while (!error && filp->f_pos < inode->i_size
188                        && offset < sb->s_blocksize) {
189                         de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
190                         if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
191                                                    bh, offset)) {
192                                 /* On error, skip the f_pos to the
193                                    next block. */
194                                 filp->f_pos = (filp->f_pos |
195                                                 (sb->s_blocksize - 1)) + 1;
196                                 brelse (bh);
197                                 ret = stored;
198                                 goto out;
199                         }
200                         offset += le16_to_cpu(de->rec_len);
201                         if (le32_to_cpu(de->inode)) {
202                                 /* We might block in the next section
203                                  * if the data destination is
204                                  * currently swapped out.  So, use a
205                                  * version stamp to detect whether or
206                                  * not the directory has been modified
207                                  * during the copy operation.
208                                  */
209                                 u64 version = filp->f_version;
210
211                                 error = filldir(dirent, de->name,
212                                                 de->name_len,
213                                                 filp->f_pos,
214                                                 le32_to_cpu(de->inode),
215                                                 get_dtype(sb, de->file_type));
216                                 if (error)
217                                         break;
218                                 if (version != filp->f_version)
219                                         goto revalidate;
220                                 stored ++;
221                         }
222                         filp->f_pos += le16_to_cpu(de->rec_len);
223                 }
224                 offset = 0;
225                 brelse (bh);
226         }
227 out:
228         return ret;
229 }
230
231 /*
232  * These functions convert from the major/minor hash to an f_pos
233  * value.
234  *
235  * Currently we only use major hash numer.  This is unfortunate, but
236  * on 32-bit machines, the same VFS interface is used for lseek and
237  * llseek, so if we use the 64 bit offset, then the 32-bit versions of
238  * lseek/telldir/seekdir will blow out spectacularly, and from within
239  * the ext2 low-level routine, we don't know if we're being called by
240  * a 64-bit version of the system call or the 32-bit version of the
241  * system call.  Worse yet, NFSv2 only allows for a 32-bit readdir
242  * cookie.  Sigh.
243  */
244 #define hash2pos(major, minor)  (major >> 1)
245 #define pos2maj_hash(pos)       ((pos << 1) & 0xffffffff)
246 #define pos2min_hash(pos)       (0)
247
248 /*
249  * This structure holds the nodes of the red-black tree used to store
250  * the directory entry in hash order.
251  */
252 struct fname {
253         __u32           hash;
254         __u32           minor_hash;
255         struct rb_node  rb_hash;
256         struct fname    *next;
257         __u32           inode;
258         __u8            name_len;
259         __u8            file_type;
260         char            name[0];
261 };
262
263 /*
264  * This functoin implements a non-recursive way of freeing all of the
265  * nodes in the red-black tree.
266  */
267 static void free_rb_tree_fname(struct rb_root *root)
268 {
269         struct rb_node  *n = root->rb_node;
270         struct rb_node  *parent;
271         struct fname    *fname;
272
273         while (n) {
274                 /* Do the node's children first */
275                 if ((n)->rb_left) {
276                         n = n->rb_left;
277                         continue;
278                 }
279                 if (n->rb_right) {
280                         n = n->rb_right;
281                         continue;
282                 }
283                 /*
284                  * The node has no children; free it, and then zero
285                  * out parent's link to it.  Finally go to the
286                  * beginning of the loop and try to free the parent
287                  * node.
288                  */
289                 parent = rb_parent(n);
290                 fname = rb_entry(n, struct fname, rb_hash);
291                 while (fname) {
292                         struct fname * old = fname;
293                         fname = fname->next;
294                         kfree (old);
295                 }
296                 if (!parent)
297                         root->rb_node = NULL;
298                 else if (parent->rb_left == n)
299                         parent->rb_left = NULL;
300                 else if (parent->rb_right == n)
301                         parent->rb_right = NULL;
302                 n = parent;
303         }
304         root->rb_node = NULL;
305 }
306
307
308 static struct dir_private_info *create_dir_info(loff_t pos)
309 {
310         struct dir_private_info *p;
311
312         p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
313         if (!p)
314                 return NULL;
315         p->root.rb_node = NULL;
316         p->curr_node = NULL;
317         p->extra_fname = NULL;
318         p->last_pos = 0;
319         p->curr_hash = pos2maj_hash(pos);
320         p->curr_minor_hash = pos2min_hash(pos);
321         p->next_hash = 0;
322         return p;
323 }
324
325 void ext3_htree_free_dir_info(struct dir_private_info *p)
326 {
327         free_rb_tree_fname(&p->root);
328         kfree(p);
329 }
330
331 /*
332  * Given a directory entry, enter it into the fname rb tree.
333  */
334 int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
335                              __u32 minor_hash,
336                              struct ext3_dir_entry_2 *dirent)
337 {
338         struct rb_node **p, *parent = NULL;
339         struct fname * fname, *new_fn;
340         struct dir_private_info *info;
341         int len;
342
343         info = (struct dir_private_info *) dir_file->private_data;
344         p = &info->root.rb_node;
345
346         /* Create and allocate the fname structure */
347         len = sizeof(struct fname) + dirent->name_len + 1;
348         new_fn = kzalloc(len, GFP_KERNEL);
349         if (!new_fn)
350                 return -ENOMEM;
351         new_fn->hash = hash;
352         new_fn->minor_hash = minor_hash;
353         new_fn->inode = le32_to_cpu(dirent->inode);
354         new_fn->name_len = dirent->name_len;
355         new_fn->file_type = dirent->file_type;
356         memcpy(new_fn->name, dirent->name, dirent->name_len);
357         new_fn->name[dirent->name_len] = 0;
358
359         while (*p) {
360                 parent = *p;
361                 fname = rb_entry(parent, struct fname, rb_hash);
362
363                 /*
364                  * If the hash and minor hash match up, then we put
365                  * them on a linked list.  This rarely happens...
366                  */
367                 if ((new_fn->hash == fname->hash) &&
368                     (new_fn->minor_hash == fname->minor_hash)) {
369                         new_fn->next = fname->next;
370                         fname->next = new_fn;
371                         return 0;
372                 }
373
374                 if (new_fn->hash < fname->hash)
375                         p = &(*p)->rb_left;
376                 else if (new_fn->hash > fname->hash)
377                         p = &(*p)->rb_right;
378                 else if (new_fn->minor_hash < fname->minor_hash)
379                         p = &(*p)->rb_left;
380                 else /* if (new_fn->minor_hash > fname->minor_hash) */
381                         p = &(*p)->rb_right;
382         }
383
384         rb_link_node(&new_fn->rb_hash, parent, p);
385         rb_insert_color(&new_fn->rb_hash, &info->root);
386         return 0;
387 }
388
389
390
391 /*
392  * This is a helper function for ext3_dx_readdir.  It calls filldir
393  * for all entres on the fname linked list.  (Normally there is only
394  * one entry on the linked list, unless there are 62 bit hash collisions.)
395  */
396 static int call_filldir(struct file * filp, void * dirent,
397                         filldir_t filldir, struct fname *fname)
398 {
399         struct dir_private_info *info = filp->private_data;
400         loff_t  curr_pos;
401         struct inode *inode = filp->f_path.dentry->d_inode;
402         struct super_block * sb;
403         int error;
404
405         sb = inode->i_sb;
406
407         if (!fname) {
408                 printk("call_filldir: called with null fname?!?\n");
409                 return 0;
410         }
411         curr_pos = hash2pos(fname->hash, fname->minor_hash);
412         while (fname) {
413                 error = filldir(dirent, fname->name,
414                                 fname->name_len, curr_pos,
415                                 fname->inode,
416                                 get_dtype(sb, fname->file_type));
417                 if (error) {
418                         filp->f_pos = curr_pos;
419                         info->extra_fname = fname->next;
420                         return error;
421                 }
422                 fname = fname->next;
423         }
424         return 0;
425 }
426
427 static int ext3_dx_readdir(struct file * filp,
428                          void * dirent, filldir_t filldir)
429 {
430         struct dir_private_info *info = filp->private_data;
431         struct inode *inode = filp->f_path.dentry->d_inode;
432         struct fname *fname;
433         int     ret;
434
435         if (!info) {
436                 info = create_dir_info(filp->f_pos);
437                 if (!info)
438                         return -ENOMEM;
439                 filp->private_data = info;
440         }
441
442         if (filp->f_pos == EXT3_HTREE_EOF)
443                 return 0;       /* EOF */
444
445         /* Some one has messed with f_pos; reset the world */
446         if (info->last_pos != filp->f_pos) {
447                 free_rb_tree_fname(&info->root);
448                 info->curr_node = NULL;
449                 info->extra_fname = NULL;
450                 info->curr_hash = pos2maj_hash(filp->f_pos);
451                 info->curr_minor_hash = pos2min_hash(filp->f_pos);
452         }
453
454         /*
455          * If there are any leftover names on the hash collision
456          * chain, return them first.
457          */
458         if (info->extra_fname &&
459             call_filldir(filp, dirent, filldir, info->extra_fname))
460                 goto finished;
461
462         if (!info->curr_node)
463                 info->curr_node = rb_first(&info->root);
464
465         while (1) {
466                 /*
467                  * Fill the rbtree if we have no more entries,
468                  * or the inode has changed since we last read in the
469                  * cached entries.
470                  */
471                 if ((!info->curr_node) ||
472                     (filp->f_version != inode->i_version)) {
473                         info->curr_node = NULL;
474                         free_rb_tree_fname(&info->root);
475                         filp->f_version = inode->i_version;
476                         ret = ext3_htree_fill_tree(filp, info->curr_hash,
477                                                    info->curr_minor_hash,
478                                                    &info->next_hash);
479                         if (ret < 0)
480                                 return ret;
481                         if (ret == 0) {
482                                 filp->f_pos = EXT3_HTREE_EOF;
483                                 break;
484                         }
485                         info->curr_node = rb_first(&info->root);
486                 }
487
488                 fname = rb_entry(info->curr_node, struct fname, rb_hash);
489                 info->curr_hash = fname->hash;
490                 info->curr_minor_hash = fname->minor_hash;
491                 if (call_filldir(filp, dirent, filldir, fname))
492                         break;
493
494                 info->curr_node = rb_next(info->curr_node);
495                 if (!info->curr_node) {
496                         if (info->next_hash == ~0) {
497                                 filp->f_pos = EXT3_HTREE_EOF;
498                                 break;
499                         }
500                         info->curr_hash = info->next_hash;
501                         info->curr_minor_hash = 0;
502                 }
503         }
504 finished:
505         info->last_pos = filp->f_pos;
506         return 0;
507 }
508
509 static int ext3_release_dir (struct inode * inode, struct file * filp)
510 {
511        if (filp->private_data)
512                 ext3_htree_free_dir_info(filp->private_data);
513
514         return 0;
515 }