ide: remove unused variables from drivers/ide/ppc/pmac.c
[sfrench/cifs-2.6.git] / fs / ext4 / namei.c
1 /*
2  *  linux/fs/ext4/namei.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/namei.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  *  Directory entry file type support and forward compatibility hooks
18  *      for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
19  *  Hash Tree Directory indexing (c)
20  *      Daniel Phillips, 2001
21  *  Hash Tree Directory indexing porting
22  *      Christopher Li, 2002
23  *  Hash Tree Directory indexing cleanup
24  *      Theodore Ts'o, 2002
25  */
26
27 #include <linux/fs.h>
28 #include <linux/pagemap.h>
29 #include <linux/jbd2.h>
30 #include <linux/time.h>
31 #include <linux/ext4_fs.h>
32 #include <linux/ext4_jbd2.h>
33 #include <linux/fcntl.h>
34 #include <linux/stat.h>
35 #include <linux/string.h>
36 #include <linux/quotaops.h>
37 #include <linux/buffer_head.h>
38 #include <linux/bio.h>
39
40 #include "namei.h"
41 #include "xattr.h"
42 #include "acl.h"
43
44 /*
45  * define how far ahead to read directories while searching them.
46  */
47 #define NAMEI_RA_CHUNKS  2
48 #define NAMEI_RA_BLOCKS  4
49 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
50 #define NAMEI_RA_INDEX(c,b)  (((c) * NAMEI_RA_BLOCKS) + (b))
51
52 static struct buffer_head *ext4_append(handle_t *handle,
53                                         struct inode *inode,
54                                         u32 *block, int *err)
55 {
56         struct buffer_head *bh;
57
58         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
59
60         if ((bh = ext4_bread(handle, inode, *block, 1, err))) {
61                 inode->i_size += inode->i_sb->s_blocksize;
62                 EXT4_I(inode)->i_disksize = inode->i_size;
63                 ext4_journal_get_write_access(handle,bh);
64         }
65         return bh;
66 }
67
68 #ifndef assert
69 #define assert(test) J_ASSERT(test)
70 #endif
71
72 #ifndef swap
73 #define swap(x, y) do { typeof(x) z = x; x = y; y = z; } while (0)
74 #endif
75
76 #ifdef DX_DEBUG
77 #define dxtrace(command) command
78 #else
79 #define dxtrace(command)
80 #endif
81
82 struct fake_dirent
83 {
84         __le32 inode;
85         __le16 rec_len;
86         u8 name_len;
87         u8 file_type;
88 };
89
90 struct dx_countlimit
91 {
92         __le16 limit;
93         __le16 count;
94 };
95
96 struct dx_entry
97 {
98         __le32 hash;
99         __le32 block;
100 };
101
102 /*
103  * dx_root_info is laid out so that if it should somehow get overlaid by a
104  * dirent the two low bits of the hash version will be zero.  Therefore, the
105  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
106  */
107
108 struct dx_root
109 {
110         struct fake_dirent dot;
111         char dot_name[4];
112         struct fake_dirent dotdot;
113         char dotdot_name[4];
114         struct dx_root_info
115         {
116                 __le32 reserved_zero;
117                 u8 hash_version;
118                 u8 info_length; /* 8 */
119                 u8 indirect_levels;
120                 u8 unused_flags;
121         }
122         info;
123         struct dx_entry entries[0];
124 };
125
126 struct dx_node
127 {
128         struct fake_dirent fake;
129         struct dx_entry entries[0];
130 };
131
132
133 struct dx_frame
134 {
135         struct buffer_head *bh;
136         struct dx_entry *entries;
137         struct dx_entry *at;
138 };
139
140 struct dx_map_entry
141 {
142         u32 hash;
143         u32 offs;
144 };
145
146 #ifdef CONFIG_EXT4_INDEX
147 static inline unsigned dx_get_block (struct dx_entry *entry);
148 static void dx_set_block (struct dx_entry *entry, unsigned value);
149 static inline unsigned dx_get_hash (struct dx_entry *entry);
150 static void dx_set_hash (struct dx_entry *entry, unsigned value);
151 static unsigned dx_get_count (struct dx_entry *entries);
152 static unsigned dx_get_limit (struct dx_entry *entries);
153 static void dx_set_count (struct dx_entry *entries, unsigned value);
154 static void dx_set_limit (struct dx_entry *entries, unsigned value);
155 static unsigned dx_root_limit (struct inode *dir, unsigned infosize);
156 static unsigned dx_node_limit (struct inode *dir);
157 static struct dx_frame *dx_probe(struct dentry *dentry,
158                                  struct inode *dir,
159                                  struct dx_hash_info *hinfo,
160                                  struct dx_frame *frame,
161                                  int *err);
162 static void dx_release (struct dx_frame *frames);
163 static int dx_make_map (struct ext4_dir_entry_2 *de, int size,
164                         struct dx_hash_info *hinfo, struct dx_map_entry map[]);
165 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
166 static struct ext4_dir_entry_2 *dx_move_dirents (char *from, char *to,
167                 struct dx_map_entry *offsets, int count);
168 static struct ext4_dir_entry_2* dx_pack_dirents (char *base, int size);
169 static void dx_insert_block (struct dx_frame *frame, u32 hash, u32 block);
170 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
171                                  struct dx_frame *frame,
172                                  struct dx_frame *frames,
173                                  __u32 *start_hash);
174 static struct buffer_head * ext4_dx_find_entry(struct dentry *dentry,
175                        struct ext4_dir_entry_2 **res_dir, int *err);
176 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
177                              struct inode *inode);
178
179 /*
180  * Future: use high four bits of block for coalesce-on-delete flags
181  * Mask them off for now.
182  */
183
184 static inline unsigned dx_get_block (struct dx_entry *entry)
185 {
186         return le32_to_cpu(entry->block) & 0x00ffffff;
187 }
188
189 static inline void dx_set_block (struct dx_entry *entry, unsigned value)
190 {
191         entry->block = cpu_to_le32(value);
192 }
193
194 static inline unsigned dx_get_hash (struct dx_entry *entry)
195 {
196         return le32_to_cpu(entry->hash);
197 }
198
199 static inline void dx_set_hash (struct dx_entry *entry, unsigned value)
200 {
201         entry->hash = cpu_to_le32(value);
202 }
203
204 static inline unsigned dx_get_count (struct dx_entry *entries)
205 {
206         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
207 }
208
209 static inline unsigned dx_get_limit (struct dx_entry *entries)
210 {
211         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
212 }
213
214 static inline void dx_set_count (struct dx_entry *entries, unsigned value)
215 {
216         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
217 }
218
219 static inline void dx_set_limit (struct dx_entry *entries, unsigned value)
220 {
221         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
222 }
223
224 static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize)
225 {
226         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
227                 EXT4_DIR_REC_LEN(2) - infosize;
228         return 0? 20: entry_space / sizeof(struct dx_entry);
229 }
230
231 static inline unsigned dx_node_limit (struct inode *dir)
232 {
233         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
234         return 0? 22: entry_space / sizeof(struct dx_entry);
235 }
236
237 /*
238  * Debug
239  */
240 #ifdef DX_DEBUG
241 static void dx_show_index (char * label, struct dx_entry *entries)
242 {
243         int i, n = dx_get_count (entries);
244         printk("%s index ", label);
245         for (i = 0; i < n; i++) {
246                 printk("%x->%u ", i? dx_get_hash(entries + i) :
247                                 0, dx_get_block(entries + i));
248         }
249         printk("\n");
250 }
251
252 struct stats
253 {
254         unsigned names;
255         unsigned space;
256         unsigned bcount;
257 };
258
259 static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext4_dir_entry_2 *de,
260                                  int size, int show_names)
261 {
262         unsigned names = 0, space = 0;
263         char *base = (char *) de;
264         struct dx_hash_info h = *hinfo;
265
266         printk("names: ");
267         while ((char *) de < base + size)
268         {
269                 if (de->inode)
270                 {
271                         if (show_names)
272                         {
273                                 int len = de->name_len;
274                                 char *name = de->name;
275                                 while (len--) printk("%c", *name++);
276                                 ext4fs_dirhash(de->name, de->name_len, &h);
277                                 printk(":%x.%u ", h.hash,
278                                        ((char *) de - base));
279                         }
280                         space += EXT4_DIR_REC_LEN(de->name_len);
281                         names++;
282                 }
283                 de = (struct ext4_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
284         }
285         printk("(%i)\n", names);
286         return (struct stats) { names, space, 1 };
287 }
288
289 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
290                              struct dx_entry *entries, int levels)
291 {
292         unsigned blocksize = dir->i_sb->s_blocksize;
293         unsigned count = dx_get_count (entries), names = 0, space = 0, i;
294         unsigned bcount = 0;
295         struct buffer_head *bh;
296         int err;
297         printk("%i indexed blocks...\n", count);
298         for (i = 0; i < count; i++, entries++)
299         {
300                 u32 block = dx_get_block(entries), hash = i? dx_get_hash(entries): 0;
301                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
302                 struct stats stats;
303                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
304                 if (!(bh = ext4_bread (NULL,dir, block, 0,&err))) continue;
305                 stats = levels?
306                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
307                    dx_show_leaf(hinfo, (struct ext4_dir_entry_2 *) bh->b_data, blocksize, 0);
308                 names += stats.names;
309                 space += stats.space;
310                 bcount += stats.bcount;
311                 brelse (bh);
312         }
313         if (bcount)
314                 printk("%snames %u, fullness %u (%u%%)\n", levels?"":"   ",
315                         names, space/bcount,(space/bcount)*100/blocksize);
316         return (struct stats) { names, space, bcount};
317 }
318 #endif /* DX_DEBUG */
319
320 /*
321  * Probe for a directory leaf block to search.
322  *
323  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
324  * error in the directory index, and the caller should fall back to
325  * searching the directory normally.  The callers of dx_probe **MUST**
326  * check for this error code, and make sure it never gets reflected
327  * back to userspace.
328  */
329 static struct dx_frame *
330 dx_probe(struct dentry *dentry, struct inode *dir,
331          struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err)
332 {
333         unsigned count, indirect;
334         struct dx_entry *at, *entries, *p, *q, *m;
335         struct dx_root *root;
336         struct buffer_head *bh;
337         struct dx_frame *frame = frame_in;
338         u32 hash;
339
340         frame->bh = NULL;
341         if (dentry)
342                 dir = dentry->d_parent->d_inode;
343         if (!(bh = ext4_bread (NULL,dir, 0, 0, err)))
344                 goto fail;
345         root = (struct dx_root *) bh->b_data;
346         if (root->info.hash_version != DX_HASH_TEA &&
347             root->info.hash_version != DX_HASH_HALF_MD4 &&
348             root->info.hash_version != DX_HASH_LEGACY) {
349                 ext4_warning(dir->i_sb, __FUNCTION__,
350                              "Unrecognised inode hash code %d",
351                              root->info.hash_version);
352                 brelse(bh);
353                 *err = ERR_BAD_DX_DIR;
354                 goto fail;
355         }
356         hinfo->hash_version = root->info.hash_version;
357         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
358         if (dentry)
359                 ext4fs_dirhash(dentry->d_name.name, dentry->d_name.len, hinfo);
360         hash = hinfo->hash;
361
362         if (root->info.unused_flags & 1) {
363                 ext4_warning(dir->i_sb, __FUNCTION__,
364                              "Unimplemented inode hash flags: %#06x",
365                              root->info.unused_flags);
366                 brelse(bh);
367                 *err = ERR_BAD_DX_DIR;
368                 goto fail;
369         }
370
371         if ((indirect = root->info.indirect_levels) > 1) {
372                 ext4_warning(dir->i_sb, __FUNCTION__,
373                              "Unimplemented inode hash depth: %#06x",
374                              root->info.indirect_levels);
375                 brelse(bh);
376                 *err = ERR_BAD_DX_DIR;
377                 goto fail;
378         }
379
380         entries = (struct dx_entry *) (((char *)&root->info) +
381                                        root->info.info_length);
382         assert(dx_get_limit(entries) == dx_root_limit(dir,
383                                                       root->info.info_length));
384         dxtrace (printk("Look up %x", hash));
385         while (1)
386         {
387                 count = dx_get_count(entries);
388                 assert (count && count <= dx_get_limit(entries));
389                 p = entries + 1;
390                 q = entries + count - 1;
391                 while (p <= q)
392                 {
393                         m = p + (q - p)/2;
394                         dxtrace(printk("."));
395                         if (dx_get_hash(m) > hash)
396                                 q = m - 1;
397                         else
398                                 p = m + 1;
399                 }
400
401                 if (0) // linear search cross check
402                 {
403                         unsigned n = count - 1;
404                         at = entries;
405                         while (n--)
406                         {
407                                 dxtrace(printk(","));
408                                 if (dx_get_hash(++at) > hash)
409                                 {
410                                         at--;
411                                         break;
412                                 }
413                         }
414                         assert (at == p - 1);
415                 }
416
417                 at = p - 1;
418                 dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at)));
419                 frame->bh = bh;
420                 frame->entries = entries;
421                 frame->at = at;
422                 if (!indirect--) return frame;
423                 if (!(bh = ext4_bread (NULL,dir, dx_get_block(at), 0, err)))
424                         goto fail2;
425                 at = entries = ((struct dx_node *) bh->b_data)->entries;
426                 assert (dx_get_limit(entries) == dx_node_limit (dir));
427                 frame++;
428         }
429 fail2:
430         while (frame >= frame_in) {
431                 brelse(frame->bh);
432                 frame--;
433         }
434 fail:
435         return NULL;
436 }
437
438 static void dx_release (struct dx_frame *frames)
439 {
440         if (frames[0].bh == NULL)
441                 return;
442
443         if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels)
444                 brelse(frames[1].bh);
445         brelse(frames[0].bh);
446 }
447
448 /*
449  * This function increments the frame pointer to search the next leaf
450  * block, and reads in the necessary intervening nodes if the search
451  * should be necessary.  Whether or not the search is necessary is
452  * controlled by the hash parameter.  If the hash value is even, then
453  * the search is only continued if the next block starts with that
454  * hash value.  This is used if we are searching for a specific file.
455  *
456  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
457  *
458  * This function returns 1 if the caller should continue to search,
459  * or 0 if it should not.  If there is an error reading one of the
460  * index blocks, it will a negative error code.
461  *
462  * If start_hash is non-null, it will be filled in with the starting
463  * hash of the next page.
464  */
465 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
466                                  struct dx_frame *frame,
467                                  struct dx_frame *frames,
468                                  __u32 *start_hash)
469 {
470         struct dx_frame *p;
471         struct buffer_head *bh;
472         int err, num_frames = 0;
473         __u32 bhash;
474
475         p = frame;
476         /*
477          * Find the next leaf page by incrementing the frame pointer.
478          * If we run out of entries in the interior node, loop around and
479          * increment pointer in the parent node.  When we break out of
480          * this loop, num_frames indicates the number of interior
481          * nodes need to be read.
482          */
483         while (1) {
484                 if (++(p->at) < p->entries + dx_get_count(p->entries))
485                         break;
486                 if (p == frames)
487                         return 0;
488                 num_frames++;
489                 p--;
490         }
491
492         /*
493          * If the hash is 1, then continue only if the next page has a
494          * continuation hash of any value.  This is used for readdir
495          * handling.  Otherwise, check to see if the hash matches the
496          * desired contiuation hash.  If it doesn't, return since
497          * there's no point to read in the successive index pages.
498          */
499         bhash = dx_get_hash(p->at);
500         if (start_hash)
501                 *start_hash = bhash;
502         if ((hash & 1) == 0) {
503                 if ((bhash & ~1) != hash)
504                         return 0;
505         }
506         /*
507          * If the hash is HASH_NB_ALWAYS, we always go to the next
508          * block so no check is necessary
509          */
510         while (num_frames--) {
511                 if (!(bh = ext4_bread(NULL, dir, dx_get_block(p->at),
512                                       0, &err)))
513                         return err; /* Failure */
514                 p++;
515                 brelse (p->bh);
516                 p->bh = bh;
517                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
518         }
519         return 1;
520 }
521
522
523 /*
524  * p is at least 6 bytes before the end of page
525  */
526 static inline struct ext4_dir_entry_2 *ext4_next_entry(struct ext4_dir_entry_2 *p)
527 {
528         return (struct ext4_dir_entry_2 *)((char*)p + le16_to_cpu(p->rec_len));
529 }
530
531 /*
532  * This function fills a red-black tree with information from a
533  * directory block.  It returns the number directory entries loaded
534  * into the tree.  If there is an error it is returned in err.
535  */
536 static int htree_dirblock_to_tree(struct file *dir_file,
537                                   struct inode *dir, int block,
538                                   struct dx_hash_info *hinfo,
539                                   __u32 start_hash, __u32 start_minor_hash)
540 {
541         struct buffer_head *bh;
542         struct ext4_dir_entry_2 *de, *top;
543         int err, count = 0;
544
545         dxtrace(printk("In htree dirblock_to_tree: block %d\n", block));
546         if (!(bh = ext4_bread (NULL, dir, block, 0, &err)))
547                 return err;
548
549         de = (struct ext4_dir_entry_2 *) bh->b_data;
550         top = (struct ext4_dir_entry_2 *) ((char *) de +
551                                            dir->i_sb->s_blocksize -
552                                            EXT4_DIR_REC_LEN(0));
553         for (; de < top; de = ext4_next_entry(de)) {
554                 if (!ext4_check_dir_entry("htree_dirblock_to_tree", dir, de, bh,
555                                         (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
556                                                 +((char *)de - bh->b_data))) {
557                         /* On error, skip the f_pos to the next block. */
558                         dir_file->f_pos = (dir_file->f_pos |
559                                         (dir->i_sb->s_blocksize - 1)) + 1;
560                         brelse (bh);
561                         return count;
562                 }
563                 ext4fs_dirhash(de->name, de->name_len, hinfo);
564                 if ((hinfo->hash < start_hash) ||
565                     ((hinfo->hash == start_hash) &&
566                      (hinfo->minor_hash < start_minor_hash)))
567                         continue;
568                 if (de->inode == 0)
569                         continue;
570                 if ((err = ext4_htree_store_dirent(dir_file,
571                                    hinfo->hash, hinfo->minor_hash, de)) != 0) {
572                         brelse(bh);
573                         return err;
574                 }
575                 count++;
576         }
577         brelse(bh);
578         return count;
579 }
580
581
582 /*
583  * This function fills a red-black tree with information from a
584  * directory.  We start scanning the directory in hash order, starting
585  * at start_hash and start_minor_hash.
586  *
587  * This function returns the number of entries inserted into the tree,
588  * or a negative error code.
589  */
590 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
591                          __u32 start_minor_hash, __u32 *next_hash)
592 {
593         struct dx_hash_info hinfo;
594         struct ext4_dir_entry_2 *de;
595         struct dx_frame frames[2], *frame;
596         struct inode *dir;
597         int block, err;
598         int count = 0;
599         int ret;
600         __u32 hashval;
601
602         dxtrace(printk("In htree_fill_tree, start hash: %x:%x\n", start_hash,
603                        start_minor_hash));
604         dir = dir_file->f_path.dentry->d_inode;
605         if (!(EXT4_I(dir)->i_flags & EXT4_INDEX_FL)) {
606                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
607                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
608                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
609                                                start_hash, start_minor_hash);
610                 *next_hash = ~0;
611                 return count;
612         }
613         hinfo.hash = start_hash;
614         hinfo.minor_hash = 0;
615         frame = dx_probe(NULL, dir_file->f_path.dentry->d_inode, &hinfo, frames, &err);
616         if (!frame)
617                 return err;
618
619         /* Add '.' and '..' from the htree header */
620         if (!start_hash && !start_minor_hash) {
621                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
622                 if ((err = ext4_htree_store_dirent(dir_file, 0, 0, de)) != 0)
623                         goto errout;
624                 count++;
625         }
626         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
627                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
628                 de = ext4_next_entry(de);
629                 if ((err = ext4_htree_store_dirent(dir_file, 2, 0, de)) != 0)
630                         goto errout;
631                 count++;
632         }
633
634         while (1) {
635                 block = dx_get_block(frame->at);
636                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
637                                              start_hash, start_minor_hash);
638                 if (ret < 0) {
639                         err = ret;
640                         goto errout;
641                 }
642                 count += ret;
643                 hashval = ~0;
644                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
645                                             frame, frames, &hashval);
646                 *next_hash = hashval;
647                 if (ret < 0) {
648                         err = ret;
649                         goto errout;
650                 }
651                 /*
652                  * Stop if:  (a) there are no more entries, or
653                  * (b) we have inserted at least one entry and the
654                  * next hash value is not a continuation
655                  */
656                 if ((ret == 0) ||
657                     (count && ((hashval & 1) == 0)))
658                         break;
659         }
660         dx_release(frames);
661         dxtrace(printk("Fill tree: returned %d entries, next hash: %x\n",
662                        count, *next_hash));
663         return count;
664 errout:
665         dx_release(frames);
666         return (err);
667 }
668
669
670 /*
671  * Directory block splitting, compacting
672  */
673
674 static int dx_make_map (struct ext4_dir_entry_2 *de, int size,
675                         struct dx_hash_info *hinfo, struct dx_map_entry *map_tail)
676 {
677         int count = 0;
678         char *base = (char *) de;
679         struct dx_hash_info h = *hinfo;
680
681         while ((char *) de < base + size)
682         {
683                 if (de->name_len && de->inode) {
684                         ext4fs_dirhash(de->name, de->name_len, &h);
685                         map_tail--;
686                         map_tail->hash = h.hash;
687                         map_tail->offs = (u32) ((char *) de - base);
688                         count++;
689                         cond_resched();
690                 }
691                 /* XXX: do we need to check rec_len == 0 case? -Chris */
692                 de = (struct ext4_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
693         }
694         return count;
695 }
696
697 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
698 {
699         struct dx_map_entry *p, *q, *top = map + count - 1;
700         int more;
701         /* Combsort until bubble sort doesn't suck */
702         while (count > 2) {
703                 count = count*10/13;
704                 if (count - 9 < 2) /* 9, 10 -> 11 */
705                         count = 11;
706                 for (p = top, q = p - count; q >= map; p--, q--)
707                         if (p->hash < q->hash)
708                                 swap(*p, *q);
709         }
710         /* Garden variety bubble sort */
711         do {
712                 more = 0;
713                 q = top;
714                 while (q-- > map) {
715                         if (q[1].hash >= q[0].hash)
716                                 continue;
717                         swap(*(q+1), *q);
718                         more = 1;
719                 }
720         } while(more);
721 }
722
723 static void dx_insert_block(struct dx_frame *frame, u32 hash, u32 block)
724 {
725         struct dx_entry *entries = frame->entries;
726         struct dx_entry *old = frame->at, *new = old + 1;
727         int count = dx_get_count(entries);
728
729         assert(count < dx_get_limit(entries));
730         assert(old < entries + count);
731         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
732         dx_set_hash(new, hash);
733         dx_set_block(new, block);
734         dx_set_count(entries, count + 1);
735 }
736 #endif
737
738
739 static void ext4_update_dx_flag(struct inode *inode)
740 {
741         if (!EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
742                                      EXT4_FEATURE_COMPAT_DIR_INDEX))
743                 EXT4_I(inode)->i_flags &= ~EXT4_INDEX_FL;
744 }
745
746 /*
747  * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.
748  *
749  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
750  * `de != NULL' is guaranteed by caller.
751  */
752 static inline int ext4_match (int len, const char * const name,
753                               struct ext4_dir_entry_2 * de)
754 {
755         if (len != de->name_len)
756                 return 0;
757         if (!de->inode)
758                 return 0;
759         return !memcmp(name, de->name, len);
760 }
761
762 /*
763  * Returns 0 if not found, -1 on failure, and 1 on success
764  */
765 static inline int search_dirblock(struct buffer_head * bh,
766                                   struct inode *dir,
767                                   struct dentry *dentry,
768                                   unsigned long offset,
769                                   struct ext4_dir_entry_2 ** res_dir)
770 {
771         struct ext4_dir_entry_2 * de;
772         char * dlimit;
773         int de_len;
774         const char *name = dentry->d_name.name;
775         int namelen = dentry->d_name.len;
776
777         de = (struct ext4_dir_entry_2 *) bh->b_data;
778         dlimit = bh->b_data + dir->i_sb->s_blocksize;
779         while ((char *) de < dlimit) {
780                 /* this code is executed quadratically often */
781                 /* do minimal checking `by hand' */
782
783                 if ((char *) de + namelen <= dlimit &&
784                     ext4_match (namelen, name, de)) {
785                         /* found a match - just to be sure, do a full check */
786                         if (!ext4_check_dir_entry("ext4_find_entry",
787                                                   dir, de, bh, offset))
788                                 return -1;
789                         *res_dir = de;
790                         return 1;
791                 }
792                 /* prevent looping on a bad block */
793                 de_len = le16_to_cpu(de->rec_len);
794                 if (de_len <= 0)
795                         return -1;
796                 offset += de_len;
797                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
798         }
799         return 0;
800 }
801
802
803 /*
804  *      ext4_find_entry()
805  *
806  * finds an entry in the specified directory with the wanted name. It
807  * returns the cache buffer in which the entry was found, and the entry
808  * itself (as a parameter - res_dir). It does NOT read the inode of the
809  * entry - you'll have to do that yourself if you want to.
810  *
811  * The returned buffer_head has ->b_count elevated.  The caller is expected
812  * to brelse() it when appropriate.
813  */
814 static struct buffer_head * ext4_find_entry (struct dentry *dentry,
815                                         struct ext4_dir_entry_2 ** res_dir)
816 {
817         struct super_block * sb;
818         struct buffer_head * bh_use[NAMEI_RA_SIZE];
819         struct buffer_head * bh, *ret = NULL;
820         unsigned long start, block, b;
821         int ra_max = 0;         /* Number of bh's in the readahead
822                                    buffer, bh_use[] */
823         int ra_ptr = 0;         /* Current index into readahead
824                                    buffer */
825         int num = 0;
826         int nblocks, i, err;
827         struct inode *dir = dentry->d_parent->d_inode;
828         int namelen;
829         const u8 *name;
830         unsigned blocksize;
831
832         *res_dir = NULL;
833         sb = dir->i_sb;
834         blocksize = sb->s_blocksize;
835         namelen = dentry->d_name.len;
836         name = dentry->d_name.name;
837         if (namelen > EXT4_NAME_LEN)
838                 return NULL;
839 #ifdef CONFIG_EXT4_INDEX
840         if (is_dx(dir)) {
841                 bh = ext4_dx_find_entry(dentry, res_dir, &err);
842                 /*
843                  * On success, or if the error was file not found,
844                  * return.  Otherwise, fall back to doing a search the
845                  * old fashioned way.
846                  */
847                 if (bh || (err != ERR_BAD_DX_DIR))
848                         return bh;
849                 dxtrace(printk("ext4_find_entry: dx failed, falling back\n"));
850         }
851 #endif
852         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
853         start = EXT4_I(dir)->i_dir_start_lookup;
854         if (start >= nblocks)
855                 start = 0;
856         block = start;
857 restart:
858         do {
859                 /*
860                  * We deal with the read-ahead logic here.
861                  */
862                 if (ra_ptr >= ra_max) {
863                         /* Refill the readahead buffer */
864                         ra_ptr = 0;
865                         b = block;
866                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
867                                 /*
868                                  * Terminate if we reach the end of the
869                                  * directory and must wrap, or if our
870                                  * search has finished at this block.
871                                  */
872                                 if (b >= nblocks || (num && block == start)) {
873                                         bh_use[ra_max] = NULL;
874                                         break;
875                                 }
876                                 num++;
877                                 bh = ext4_getblk(NULL, dir, b++, 0, &err);
878                                 bh_use[ra_max] = bh;
879                                 if (bh)
880                                         ll_rw_block(READ_META, 1, &bh);
881                         }
882                 }
883                 if ((bh = bh_use[ra_ptr++]) == NULL)
884                         goto next;
885                 wait_on_buffer(bh);
886                 if (!buffer_uptodate(bh)) {
887                         /* read error, skip block & hope for the best */
888                         ext4_error(sb, __FUNCTION__, "reading directory #%lu "
889                                    "offset %lu", dir->i_ino, block);
890                         brelse(bh);
891                         goto next;
892                 }
893                 i = search_dirblock(bh, dir, dentry,
894                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
895                 if (i == 1) {
896                         EXT4_I(dir)->i_dir_start_lookup = block;
897                         ret = bh;
898                         goto cleanup_and_exit;
899                 } else {
900                         brelse(bh);
901                         if (i < 0)
902                                 goto cleanup_and_exit;
903                 }
904         next:
905                 if (++block >= nblocks)
906                         block = 0;
907         } while (block != start);
908
909         /*
910          * If the directory has grown while we were searching, then
911          * search the last part of the directory before giving up.
912          */
913         block = nblocks;
914         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
915         if (block < nblocks) {
916                 start = 0;
917                 goto restart;
918         }
919
920 cleanup_and_exit:
921         /* Clean up the read-ahead blocks */
922         for (; ra_ptr < ra_max; ra_ptr++)
923                 brelse (bh_use[ra_ptr]);
924         return ret;
925 }
926
927 #ifdef CONFIG_EXT4_INDEX
928 static struct buffer_head * ext4_dx_find_entry(struct dentry *dentry,
929                        struct ext4_dir_entry_2 **res_dir, int *err)
930 {
931         struct super_block * sb;
932         struct dx_hash_info     hinfo;
933         u32 hash;
934         struct dx_frame frames[2], *frame;
935         struct ext4_dir_entry_2 *de, *top;
936         struct buffer_head *bh;
937         unsigned long block;
938         int retval;
939         int namelen = dentry->d_name.len;
940         const u8 *name = dentry->d_name.name;
941         struct inode *dir = dentry->d_parent->d_inode;
942
943         sb = dir->i_sb;
944         /* NFS may look up ".." - look at dx_root directory block */
945         if (namelen > 2 || name[0] != '.'||(name[1] != '.' && name[1] != '\0')){
946                 if (!(frame = dx_probe(dentry, NULL, &hinfo, frames, err)))
947                         return NULL;
948         } else {
949                 frame = frames;
950                 frame->bh = NULL;                       /* for dx_release() */
951                 frame->at = (struct dx_entry *)frames;  /* hack for zero entry*/
952                 dx_set_block(frame->at, 0);             /* dx_root block is 0 */
953         }
954         hash = hinfo.hash;
955         do {
956                 block = dx_get_block(frame->at);
957                 if (!(bh = ext4_bread (NULL,dir, block, 0, err)))
958                         goto errout;
959                 de = (struct ext4_dir_entry_2 *) bh->b_data;
960                 top = (struct ext4_dir_entry_2 *) ((char *) de + sb->s_blocksize -
961                                        EXT4_DIR_REC_LEN(0));
962                 for (; de < top; de = ext4_next_entry(de))
963                 if (ext4_match (namelen, name, de)) {
964                         if (!ext4_check_dir_entry("ext4_find_entry",
965                                                   dir, de, bh,
966                                   (block<<EXT4_BLOCK_SIZE_BITS(sb))
967                                           +((char *)de - bh->b_data))) {
968                                 brelse (bh);
969                                 *err = ERR_BAD_DX_DIR;
970                                 goto errout;
971                         }
972                         *res_dir = de;
973                         dx_release (frames);
974                         return bh;
975                 }
976                 brelse (bh);
977                 /* Check to see if we should continue to search */
978                 retval = ext4_htree_next_block(dir, hash, frame,
979                                                frames, NULL);
980                 if (retval < 0) {
981                         ext4_warning(sb, __FUNCTION__,
982                              "error reading index page in directory #%lu",
983                              dir->i_ino);
984                         *err = retval;
985                         goto errout;
986                 }
987         } while (retval == 1);
988
989         *err = -ENOENT;
990 errout:
991         dxtrace(printk("%s not found\n", name));
992         dx_release (frames);
993         return NULL;
994 }
995 #endif
996
997 static struct dentry *ext4_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
998 {
999         struct inode * inode;
1000         struct ext4_dir_entry_2 * de;
1001         struct buffer_head * bh;
1002
1003         if (dentry->d_name.len > EXT4_NAME_LEN)
1004                 return ERR_PTR(-ENAMETOOLONG);
1005
1006         bh = ext4_find_entry(dentry, &de);
1007         inode = NULL;
1008         if (bh) {
1009                 unsigned long ino = le32_to_cpu(de->inode);
1010                 brelse (bh);
1011                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1012                         ext4_error(dir->i_sb, "ext4_lookup",
1013                                    "bad inode number: %lu", ino);
1014                         inode = NULL;
1015                 } else
1016                         inode = iget(dir->i_sb, ino);
1017
1018                 if (!inode)
1019                         return ERR_PTR(-EACCES);
1020
1021                 if (is_bad_inode(inode)) {
1022                         iput(inode);
1023                         return ERR_PTR(-ENOENT);
1024                 }
1025         }
1026         return d_splice_alias(inode, dentry);
1027 }
1028
1029
1030 struct dentry *ext4_get_parent(struct dentry *child)
1031 {
1032         unsigned long ino;
1033         struct dentry *parent;
1034         struct inode *inode;
1035         struct dentry dotdot;
1036         struct ext4_dir_entry_2 * de;
1037         struct buffer_head *bh;
1038
1039         dotdot.d_name.name = "..";
1040         dotdot.d_name.len = 2;
1041         dotdot.d_parent = child; /* confusing, isn't it! */
1042
1043         bh = ext4_find_entry(&dotdot, &de);
1044         inode = NULL;
1045         if (!bh)
1046                 return ERR_PTR(-ENOENT);
1047         ino = le32_to_cpu(de->inode);
1048         brelse(bh);
1049
1050         if (!ext4_valid_inum(child->d_inode->i_sb, ino)) {
1051                 ext4_error(child->d_inode->i_sb, "ext4_get_parent",
1052                            "bad inode number: %lu", ino);
1053                 inode = NULL;
1054         } else
1055                 inode = iget(child->d_inode->i_sb, ino);
1056
1057         if (!inode)
1058                 return ERR_PTR(-EACCES);
1059
1060         if (is_bad_inode(inode)) {
1061                 iput(inode);
1062                 return ERR_PTR(-ENOENT);
1063         }
1064
1065         parent = d_alloc_anon(inode);
1066         if (!parent) {
1067                 iput(inode);
1068                 parent = ERR_PTR(-ENOMEM);
1069         }
1070         return parent;
1071 }
1072
1073 #define S_SHIFT 12
1074 static unsigned char ext4_type_by_mode[S_IFMT >> S_SHIFT] = {
1075         [S_IFREG >> S_SHIFT]    = EXT4_FT_REG_FILE,
1076         [S_IFDIR >> S_SHIFT]    = EXT4_FT_DIR,
1077         [S_IFCHR >> S_SHIFT]    = EXT4_FT_CHRDEV,
1078         [S_IFBLK >> S_SHIFT]    = EXT4_FT_BLKDEV,
1079         [S_IFIFO >> S_SHIFT]    = EXT4_FT_FIFO,
1080         [S_IFSOCK >> S_SHIFT]   = EXT4_FT_SOCK,
1081         [S_IFLNK >> S_SHIFT]    = EXT4_FT_SYMLINK,
1082 };
1083
1084 static inline void ext4_set_de_type(struct super_block *sb,
1085                                 struct ext4_dir_entry_2 *de,
1086                                 umode_t mode) {
1087         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE))
1088                 de->file_type = ext4_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
1089 }
1090
1091 #ifdef CONFIG_EXT4_INDEX
1092 static struct ext4_dir_entry_2 *
1093 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count)
1094 {
1095         unsigned rec_len = 0;
1096
1097         while (count--) {
1098                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *) (from + map->offs);
1099                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1100                 memcpy (to, de, rec_len);
1101                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1102                                 cpu_to_le16(rec_len);
1103                 de->inode = 0;
1104                 map++;
1105                 to += rec_len;
1106         }
1107         return (struct ext4_dir_entry_2 *) (to - rec_len);
1108 }
1109
1110 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, int size)
1111 {
1112         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1113         unsigned rec_len = 0;
1114
1115         prev = to = de;
1116         while ((char*)de < base + size) {
1117                 next = (struct ext4_dir_entry_2 *) ((char *) de +
1118                                                     le16_to_cpu(de->rec_len));
1119                 if (de->inode && de->name_len) {
1120                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1121                         if (de > to)
1122                                 memmove(to, de, rec_len);
1123                         to->rec_len = cpu_to_le16(rec_len);
1124                         prev = to;
1125                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1126                 }
1127                 de = next;
1128         }
1129         return prev;
1130 }
1131
1132 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1133                         struct buffer_head **bh,struct dx_frame *frame,
1134                         struct dx_hash_info *hinfo, int *error)
1135 {
1136         unsigned blocksize = dir->i_sb->s_blocksize;
1137         unsigned count, continued;
1138         struct buffer_head *bh2;
1139         u32 newblock;
1140         u32 hash2;
1141         struct dx_map_entry *map;
1142         char *data1 = (*bh)->b_data, *data2;
1143         unsigned split;
1144         struct ext4_dir_entry_2 *de = NULL, *de2;
1145         int     err = 0;
1146
1147         bh2 = ext4_append (handle, dir, &newblock, &err);
1148         if (!(bh2)) {
1149                 brelse(*bh);
1150                 *bh = NULL;
1151                 goto errout;
1152         }
1153
1154         BUFFER_TRACE(*bh, "get_write_access");
1155         err = ext4_journal_get_write_access(handle, *bh);
1156         if (err)
1157                 goto journal_error;
1158
1159         BUFFER_TRACE(frame->bh, "get_write_access");
1160         err = ext4_journal_get_write_access(handle, frame->bh);
1161         if (err)
1162                 goto journal_error;
1163
1164         data2 = bh2->b_data;
1165
1166         /* create map in the end of data2 block */
1167         map = (struct dx_map_entry *) (data2 + blocksize);
1168         count = dx_make_map ((struct ext4_dir_entry_2 *) data1,
1169                              blocksize, hinfo, map);
1170         map -= count;
1171         split = count/2; // need to adjust to actual middle
1172         dx_sort_map (map, count);
1173         hash2 = map[split].hash;
1174         continued = hash2 == map[split - 1].hash;
1175         dxtrace(printk("Split block %i at %x, %i/%i\n",
1176                 dx_get_block(frame->at), hash2, split, count-split));
1177
1178         /* Fancy dance to stay within two buffers */
1179         de2 = dx_move_dirents(data1, data2, map + split, count - split);
1180         de = dx_pack_dirents(data1,blocksize);
1181         de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
1182         de2->rec_len = cpu_to_le16(data2 + blocksize - (char *) de2);
1183         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
1184         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
1185
1186         /* Which block gets the new entry? */
1187         if (hinfo->hash >= hash2)
1188         {
1189                 swap(*bh, bh2);
1190                 de = de2;
1191         }
1192         dx_insert_block (frame, hash2 + continued, newblock);
1193         err = ext4_journal_dirty_metadata (handle, bh2);
1194         if (err)
1195                 goto journal_error;
1196         err = ext4_journal_dirty_metadata (handle, frame->bh);
1197         if (err)
1198                 goto journal_error;
1199         brelse (bh2);
1200         dxtrace(dx_show_index ("frame", frame->entries));
1201         return de;
1202
1203 journal_error:
1204         brelse(*bh);
1205         brelse(bh2);
1206         *bh = NULL;
1207         ext4_std_error(dir->i_sb, err);
1208 errout:
1209         *error = err;
1210         return NULL;
1211 }
1212 #endif
1213
1214
1215 /*
1216  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1217  * it points to a directory entry which is guaranteed to be large
1218  * enough for new directory entry.  If de is NULL, then
1219  * add_dirent_to_buf will attempt search the directory block for
1220  * space.  It will return -ENOSPC if no space is available, and -EIO
1221  * and -EEXIST if directory entry already exists.
1222  *
1223  * NOTE!  bh is NOT released in the case where ENOSPC is returned.  In
1224  * all other cases bh is released.
1225  */
1226 static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
1227                              struct inode *inode, struct ext4_dir_entry_2 *de,
1228                              struct buffer_head * bh)
1229 {
1230         struct inode    *dir = dentry->d_parent->d_inode;
1231         const char      *name = dentry->d_name.name;
1232         int             namelen = dentry->d_name.len;
1233         unsigned long   offset = 0;
1234         unsigned short  reclen;
1235         int             nlen, rlen, err;
1236         char            *top;
1237
1238         reclen = EXT4_DIR_REC_LEN(namelen);
1239         if (!de) {
1240                 de = (struct ext4_dir_entry_2 *)bh->b_data;
1241                 top = bh->b_data + dir->i_sb->s_blocksize - reclen;
1242                 while ((char *) de <= top) {
1243                         if (!ext4_check_dir_entry("ext4_add_entry", dir, de,
1244                                                   bh, offset)) {
1245                                 brelse (bh);
1246                                 return -EIO;
1247                         }
1248                         if (ext4_match (namelen, name, de)) {
1249                                 brelse (bh);
1250                                 return -EEXIST;
1251                         }
1252                         nlen = EXT4_DIR_REC_LEN(de->name_len);
1253                         rlen = le16_to_cpu(de->rec_len);
1254                         if ((de->inode? rlen - nlen: rlen) >= reclen)
1255                                 break;
1256                         de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1257                         offset += rlen;
1258                 }
1259                 if ((char *) de > top)
1260                         return -ENOSPC;
1261         }
1262         BUFFER_TRACE(bh, "get_write_access");
1263         err = ext4_journal_get_write_access(handle, bh);
1264         if (err) {
1265                 ext4_std_error(dir->i_sb, err);
1266                 brelse(bh);
1267                 return err;
1268         }
1269
1270         /* By now the buffer is marked for journaling */
1271         nlen = EXT4_DIR_REC_LEN(de->name_len);
1272         rlen = le16_to_cpu(de->rec_len);
1273         if (de->inode) {
1274                 struct ext4_dir_entry_2 *de1 = (struct ext4_dir_entry_2 *)((char *)de + nlen);
1275                 de1->rec_len = cpu_to_le16(rlen - nlen);
1276                 de->rec_len = cpu_to_le16(nlen);
1277                 de = de1;
1278         }
1279         de->file_type = EXT4_FT_UNKNOWN;
1280         if (inode) {
1281                 de->inode = cpu_to_le32(inode->i_ino);
1282                 ext4_set_de_type(dir->i_sb, de, inode->i_mode);
1283         } else
1284                 de->inode = 0;
1285         de->name_len = namelen;
1286         memcpy (de->name, name, namelen);
1287         /*
1288          * XXX shouldn't update any times until successful
1289          * completion of syscall, but too many callers depend
1290          * on this.
1291          *
1292          * XXX similarly, too many callers depend on
1293          * ext4_new_inode() setting the times, but error
1294          * recovery deletes the inode, so the worst that can
1295          * happen is that the times are slightly out of date
1296          * and/or different from the directory change time.
1297          */
1298         dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
1299         ext4_update_dx_flag(dir);
1300         dir->i_version++;
1301         ext4_mark_inode_dirty(handle, dir);
1302         BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
1303         err = ext4_journal_dirty_metadata(handle, bh);
1304         if (err)
1305                 ext4_std_error(dir->i_sb, err);
1306         brelse(bh);
1307         return 0;
1308 }
1309
1310 #ifdef CONFIG_EXT4_INDEX
1311 /*
1312  * This converts a one block unindexed directory to a 3 block indexed
1313  * directory, and adds the dentry to the indexed directory.
1314  */
1315 static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1316                             struct inode *inode, struct buffer_head *bh)
1317 {
1318         struct inode    *dir = dentry->d_parent->d_inode;
1319         const char      *name = dentry->d_name.name;
1320         int             namelen = dentry->d_name.len;
1321         struct buffer_head *bh2;
1322         struct dx_root  *root;
1323         struct dx_frame frames[2], *frame;
1324         struct dx_entry *entries;
1325         struct ext4_dir_entry_2 *de, *de2;
1326         char            *data1, *top;
1327         unsigned        len;
1328         int             retval;
1329         unsigned        blocksize;
1330         struct dx_hash_info hinfo;
1331         u32             block;
1332         struct fake_dirent *fde;
1333
1334         blocksize =  dir->i_sb->s_blocksize;
1335         dxtrace(printk("Creating index\n"));
1336         retval = ext4_journal_get_write_access(handle, bh);
1337         if (retval) {
1338                 ext4_std_error(dir->i_sb, retval);
1339                 brelse(bh);
1340                 return retval;
1341         }
1342         root = (struct dx_root *) bh->b_data;
1343
1344         bh2 = ext4_append (handle, dir, &block, &retval);
1345         if (!(bh2)) {
1346                 brelse(bh);
1347                 return retval;
1348         }
1349         EXT4_I(dir)->i_flags |= EXT4_INDEX_FL;
1350         data1 = bh2->b_data;
1351
1352         /* The 0th block becomes the root, move the dirents out */
1353         fde = &root->dotdot;
1354         de = (struct ext4_dir_entry_2 *)((char *)fde + le16_to_cpu(fde->rec_len));
1355         len = ((char *) root) + blocksize - (char *) de;
1356         memcpy (data1, de, len);
1357         de = (struct ext4_dir_entry_2 *) data1;
1358         top = data1 + len;
1359         while ((char *)(de2=(void*)de+le16_to_cpu(de->rec_len)) < top)
1360                 de = de2;
1361         de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
1362         /* Initialize the root; the dot dirents already exist */
1363         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1364         de->rec_len = cpu_to_le16(blocksize - EXT4_DIR_REC_LEN(2));
1365         memset (&root->info, 0, sizeof(root->info));
1366         root->info.info_length = sizeof(root->info);
1367         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1368         entries = root->entries;
1369         dx_set_block (entries, 1);
1370         dx_set_count (entries, 1);
1371         dx_set_limit (entries, dx_root_limit(dir, sizeof(root->info)));
1372
1373         /* Initialize as for dx_probe */
1374         hinfo.hash_version = root->info.hash_version;
1375         hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1376         ext4fs_dirhash(name, namelen, &hinfo);
1377         frame = frames;
1378         frame->entries = entries;
1379         frame->at = entries;
1380         frame->bh = bh;
1381         bh = bh2;
1382         de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
1383         dx_release (frames);
1384         if (!(de))
1385                 return retval;
1386
1387         return add_dirent_to_buf(handle, dentry, inode, de, bh);
1388 }
1389 #endif
1390
1391 /*
1392  *      ext4_add_entry()
1393  *
1394  * adds a file entry to the specified directory, using the same
1395  * semantics as ext4_find_entry(). It returns NULL if it failed.
1396  *
1397  * NOTE!! The inode part of 'de' is left at 0 - which means you
1398  * may not sleep between calling this and putting something into
1399  * the entry, as someone else might have used it while you slept.
1400  */
1401 static int ext4_add_entry (handle_t *handle, struct dentry *dentry,
1402         struct inode *inode)
1403 {
1404         struct inode *dir = dentry->d_parent->d_inode;
1405         unsigned long offset;
1406         struct buffer_head * bh;
1407         struct ext4_dir_entry_2 *de;
1408         struct super_block * sb;
1409         int     retval;
1410 #ifdef CONFIG_EXT4_INDEX
1411         int     dx_fallback=0;
1412 #endif
1413         unsigned blocksize;
1414         u32 block, blocks;
1415
1416         sb = dir->i_sb;
1417         blocksize = sb->s_blocksize;
1418         if (!dentry->d_name.len)
1419                 return -EINVAL;
1420 #ifdef CONFIG_EXT4_INDEX
1421         if (is_dx(dir)) {
1422                 retval = ext4_dx_add_entry(handle, dentry, inode);
1423                 if (!retval || (retval != ERR_BAD_DX_DIR))
1424                         return retval;
1425                 EXT4_I(dir)->i_flags &= ~EXT4_INDEX_FL;
1426                 dx_fallback++;
1427                 ext4_mark_inode_dirty(handle, dir);
1428         }
1429 #endif
1430         blocks = dir->i_size >> sb->s_blocksize_bits;
1431         for (block = 0, offset = 0; block < blocks; block++) {
1432                 bh = ext4_bread(handle, dir, block, 0, &retval);
1433                 if(!bh)
1434                         return retval;
1435                 retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1436                 if (retval != -ENOSPC)
1437                         return retval;
1438
1439 #ifdef CONFIG_EXT4_INDEX
1440                 if (blocks == 1 && !dx_fallback &&
1441                     EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX))
1442                         return make_indexed_dir(handle, dentry, inode, bh);
1443 #endif
1444                 brelse(bh);
1445         }
1446         bh = ext4_append(handle, dir, &block, &retval);
1447         if (!bh)
1448                 return retval;
1449         de = (struct ext4_dir_entry_2 *) bh->b_data;
1450         de->inode = 0;
1451         de->rec_len = cpu_to_le16(blocksize);
1452         return add_dirent_to_buf(handle, dentry, inode, de, bh);
1453 }
1454
1455 #ifdef CONFIG_EXT4_INDEX
1456 /*
1457  * Returns 0 for success, or a negative error value
1458  */
1459 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
1460                              struct inode *inode)
1461 {
1462         struct dx_frame frames[2], *frame;
1463         struct dx_entry *entries, *at;
1464         struct dx_hash_info hinfo;
1465         struct buffer_head * bh;
1466         struct inode *dir = dentry->d_parent->d_inode;
1467         struct super_block * sb = dir->i_sb;
1468         struct ext4_dir_entry_2 *de;
1469         int err;
1470
1471         frame = dx_probe(dentry, NULL, &hinfo, frames, &err);
1472         if (!frame)
1473                 return err;
1474         entries = frame->entries;
1475         at = frame->at;
1476
1477         if (!(bh = ext4_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
1478                 goto cleanup;
1479
1480         BUFFER_TRACE(bh, "get_write_access");
1481         err = ext4_journal_get_write_access(handle, bh);
1482         if (err)
1483                 goto journal_error;
1484
1485         err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1486         if (err != -ENOSPC) {
1487                 bh = NULL;
1488                 goto cleanup;
1489         }
1490
1491         /* Block full, should compress but for now just split */
1492         dxtrace(printk("using %u of %u node entries\n",
1493                        dx_get_count(entries), dx_get_limit(entries)));
1494         /* Need to split index? */
1495         if (dx_get_count(entries) == dx_get_limit(entries)) {
1496                 u32 newblock;
1497                 unsigned icount = dx_get_count(entries);
1498                 int levels = frame - frames;
1499                 struct dx_entry *entries2;
1500                 struct dx_node *node2;
1501                 struct buffer_head *bh2;
1502
1503                 if (levels && (dx_get_count(frames->entries) ==
1504                                dx_get_limit(frames->entries))) {
1505                         ext4_warning(sb, __FUNCTION__,
1506                                      "Directory index full!");
1507                         err = -ENOSPC;
1508                         goto cleanup;
1509                 }
1510                 bh2 = ext4_append (handle, dir, &newblock, &err);
1511                 if (!(bh2))
1512                         goto cleanup;
1513                 node2 = (struct dx_node *)(bh2->b_data);
1514                 entries2 = node2->entries;
1515                 node2->fake.rec_len = cpu_to_le16(sb->s_blocksize);
1516                 node2->fake.inode = 0;
1517                 BUFFER_TRACE(frame->bh, "get_write_access");
1518                 err = ext4_journal_get_write_access(handle, frame->bh);
1519                 if (err)
1520                         goto journal_error;
1521                 if (levels) {
1522                         unsigned icount1 = icount/2, icount2 = icount - icount1;
1523                         unsigned hash2 = dx_get_hash(entries + icount1);
1524                         dxtrace(printk("Split index %i/%i\n", icount1, icount2));
1525
1526                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
1527                         err = ext4_journal_get_write_access(handle,
1528                                                              frames[0].bh);
1529                         if (err)
1530                                 goto journal_error;
1531
1532                         memcpy ((char *) entries2, (char *) (entries + icount1),
1533                                 icount2 * sizeof(struct dx_entry));
1534                         dx_set_count (entries, icount1);
1535                         dx_set_count (entries2, icount2);
1536                         dx_set_limit (entries2, dx_node_limit(dir));
1537
1538                         /* Which index block gets the new entry? */
1539                         if (at - entries >= icount1) {
1540                                 frame->at = at = at - entries - icount1 + entries2;
1541                                 frame->entries = entries = entries2;
1542                                 swap(frame->bh, bh2);
1543                         }
1544                         dx_insert_block (frames + 0, hash2, newblock);
1545                         dxtrace(dx_show_index ("node", frames[1].entries));
1546                         dxtrace(dx_show_index ("node",
1547                                ((struct dx_node *) bh2->b_data)->entries));
1548                         err = ext4_journal_dirty_metadata(handle, bh2);
1549                         if (err)
1550                                 goto journal_error;
1551                         brelse (bh2);
1552                 } else {
1553                         dxtrace(printk("Creating second level index...\n"));
1554                         memcpy((char *) entries2, (char *) entries,
1555                                icount * sizeof(struct dx_entry));
1556                         dx_set_limit(entries2, dx_node_limit(dir));
1557
1558                         /* Set up root */
1559                         dx_set_count(entries, 1);
1560                         dx_set_block(entries + 0, newblock);
1561                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
1562
1563                         /* Add new access path frame */
1564                         frame = frames + 1;
1565                         frame->at = at = at - entries + entries2;
1566                         frame->entries = entries = entries2;
1567                         frame->bh = bh2;
1568                         err = ext4_journal_get_write_access(handle,
1569                                                              frame->bh);
1570                         if (err)
1571                                 goto journal_error;
1572                 }
1573                 ext4_journal_dirty_metadata(handle, frames[0].bh);
1574         }
1575         de = do_split(handle, dir, &bh, frame, &hinfo, &err);
1576         if (!de)
1577                 goto cleanup;
1578         err = add_dirent_to_buf(handle, dentry, inode, de, bh);
1579         bh = NULL;
1580         goto cleanup;
1581
1582 journal_error:
1583         ext4_std_error(dir->i_sb, err);
1584 cleanup:
1585         if (bh)
1586                 brelse(bh);
1587         dx_release(frames);
1588         return err;
1589 }
1590 #endif
1591
1592 /*
1593  * ext4_delete_entry deletes a directory entry by merging it with the
1594  * previous entry
1595  */
1596 static int ext4_delete_entry (handle_t *handle,
1597                               struct inode * dir,
1598                               struct ext4_dir_entry_2 * de_del,
1599                               struct buffer_head * bh)
1600 {
1601         struct ext4_dir_entry_2 * de, * pde;
1602         int i;
1603
1604         i = 0;
1605         pde = NULL;
1606         de = (struct ext4_dir_entry_2 *) bh->b_data;
1607         while (i < bh->b_size) {
1608                 if (!ext4_check_dir_entry("ext4_delete_entry", dir, de, bh, i))
1609                         return -EIO;
1610                 if (de == de_del)  {
1611                         BUFFER_TRACE(bh, "get_write_access");
1612                         ext4_journal_get_write_access(handle, bh);
1613                         if (pde)
1614                                 pde->rec_len =
1615                                         cpu_to_le16(le16_to_cpu(pde->rec_len) +
1616                                                     le16_to_cpu(de->rec_len));
1617                         else
1618                                 de->inode = 0;
1619                         dir->i_version++;
1620                         BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
1621                         ext4_journal_dirty_metadata(handle, bh);
1622                         return 0;
1623                 }
1624                 i += le16_to_cpu(de->rec_len);
1625                 pde = de;
1626                 de = (struct ext4_dir_entry_2 *)
1627                         ((char *) de + le16_to_cpu(de->rec_len));
1628         }
1629         return -ENOENT;
1630 }
1631
1632 /*
1633  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
1634  * since this indicates that nlinks count was previously 1.
1635  */
1636 static void ext4_inc_count(handle_t *handle, struct inode *inode)
1637 {
1638         inc_nlink(inode);
1639         if (is_dx(inode) && inode->i_nlink > 1) {
1640                 /* limit is 16-bit i_links_count */
1641                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
1642                         inode->i_nlink = 1;
1643                         EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb,
1644                                               EXT4_FEATURE_RO_COMPAT_DIR_NLINK);
1645                 }
1646         }
1647 }
1648
1649 /*
1650  * If a directory had nlink == 1, then we should let it be 1. This indicates
1651  * directory has >EXT4_LINK_MAX subdirs.
1652  */
1653 static void ext4_dec_count(handle_t *handle, struct inode *inode)
1654 {
1655         drop_nlink(inode);
1656         if (S_ISDIR(inode->i_mode) && inode->i_nlink == 0)
1657                 inc_nlink(inode);
1658 }
1659
1660
1661 static int ext4_add_nondir(handle_t *handle,
1662                 struct dentry *dentry, struct inode *inode)
1663 {
1664         int err = ext4_add_entry(handle, dentry, inode);
1665         if (!err) {
1666                 ext4_mark_inode_dirty(handle, inode);
1667                 d_instantiate(dentry, inode);
1668                 return 0;
1669         }
1670         drop_nlink(inode);
1671         iput(inode);
1672         return err;
1673 }
1674
1675 /*
1676  * By the time this is called, we already have created
1677  * the directory cache entry for the new file, but it
1678  * is so far negative - it has no inode.
1679  *
1680  * If the create succeeds, we fill in the inode information
1681  * with d_instantiate().
1682  */
1683 static int ext4_create (struct inode * dir, struct dentry * dentry, int mode,
1684                 struct nameidata *nd)
1685 {
1686         handle_t *handle;
1687         struct inode * inode;
1688         int err, retries = 0;
1689
1690 retry:
1691         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
1692                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
1693                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
1694         if (IS_ERR(handle))
1695                 return PTR_ERR(handle);
1696
1697         if (IS_DIRSYNC(dir))
1698                 handle->h_sync = 1;
1699
1700         inode = ext4_new_inode (handle, dir, mode);
1701         err = PTR_ERR(inode);
1702         if (!IS_ERR(inode)) {
1703                 inode->i_op = &ext4_file_inode_operations;
1704                 inode->i_fop = &ext4_file_operations;
1705                 ext4_set_aops(inode);
1706                 err = ext4_add_nondir(handle, dentry, inode);
1707         }
1708         ext4_journal_stop(handle);
1709         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
1710                 goto retry;
1711         return err;
1712 }
1713
1714 static int ext4_mknod (struct inode * dir, struct dentry *dentry,
1715                         int mode, dev_t rdev)
1716 {
1717         handle_t *handle;
1718         struct inode *inode;
1719         int err, retries = 0;
1720
1721         if (!new_valid_dev(rdev))
1722                 return -EINVAL;
1723
1724 retry:
1725         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
1726                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
1727                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
1728         if (IS_ERR(handle))
1729                 return PTR_ERR(handle);
1730
1731         if (IS_DIRSYNC(dir))
1732                 handle->h_sync = 1;
1733
1734         inode = ext4_new_inode (handle, dir, mode);
1735         err = PTR_ERR(inode);
1736         if (!IS_ERR(inode)) {
1737                 init_special_inode(inode, inode->i_mode, rdev);
1738 #ifdef CONFIG_EXT4DEV_FS_XATTR
1739                 inode->i_op = &ext4_special_inode_operations;
1740 #endif
1741                 err = ext4_add_nondir(handle, dentry, inode);
1742         }
1743         ext4_journal_stop(handle);
1744         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
1745                 goto retry;
1746         return err;
1747 }
1748
1749 static int ext4_mkdir(struct inode * dir, struct dentry * dentry, int mode)
1750 {
1751         handle_t *handle;
1752         struct inode * inode;
1753         struct buffer_head * dir_block;
1754         struct ext4_dir_entry_2 * de;
1755         int err, retries = 0;
1756
1757         if (EXT4_DIR_LINK_MAX(dir))
1758                 return -EMLINK;
1759
1760 retry:
1761         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
1762                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
1763                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
1764         if (IS_ERR(handle))
1765                 return PTR_ERR(handle);
1766
1767         if (IS_DIRSYNC(dir))
1768                 handle->h_sync = 1;
1769
1770         inode = ext4_new_inode (handle, dir, S_IFDIR | mode);
1771         err = PTR_ERR(inode);
1772         if (IS_ERR(inode))
1773                 goto out_stop;
1774
1775         inode->i_op = &ext4_dir_inode_operations;
1776         inode->i_fop = &ext4_dir_operations;
1777         inode->i_size = EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
1778         dir_block = ext4_bread (handle, inode, 0, 1, &err);
1779         if (!dir_block) {
1780                 ext4_dec_count(handle, inode); /* is this nlink == 0? */
1781                 ext4_mark_inode_dirty(handle, inode);
1782                 iput (inode);
1783                 goto out_stop;
1784         }
1785         BUFFER_TRACE(dir_block, "get_write_access");
1786         ext4_journal_get_write_access(handle, dir_block);
1787         de = (struct ext4_dir_entry_2 *) dir_block->b_data;
1788         de->inode = cpu_to_le32(inode->i_ino);
1789         de->name_len = 1;
1790         de->rec_len = cpu_to_le16(EXT4_DIR_REC_LEN(de->name_len));
1791         strcpy (de->name, ".");
1792         ext4_set_de_type(dir->i_sb, de, S_IFDIR);
1793         de = (struct ext4_dir_entry_2 *)
1794                         ((char *) de + le16_to_cpu(de->rec_len));
1795         de->inode = cpu_to_le32(dir->i_ino);
1796         de->rec_len = cpu_to_le16(inode->i_sb->s_blocksize-EXT4_DIR_REC_LEN(1));
1797         de->name_len = 2;
1798         strcpy (de->name, "..");
1799         ext4_set_de_type(dir->i_sb, de, S_IFDIR);
1800         inode->i_nlink = 2;
1801         BUFFER_TRACE(dir_block, "call ext4_journal_dirty_metadata");
1802         ext4_journal_dirty_metadata(handle, dir_block);
1803         brelse (dir_block);
1804         ext4_mark_inode_dirty(handle, inode);
1805         err = ext4_add_entry (handle, dentry, inode);
1806         if (err) {
1807                 inode->i_nlink = 0;
1808                 ext4_mark_inode_dirty(handle, inode);
1809                 iput (inode);
1810                 goto out_stop;
1811         }
1812         ext4_inc_count(handle, dir);
1813         ext4_update_dx_flag(dir);
1814         ext4_mark_inode_dirty(handle, dir);
1815         d_instantiate(dentry, inode);
1816 out_stop:
1817         ext4_journal_stop(handle);
1818         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
1819                 goto retry;
1820         return err;
1821 }
1822
1823 /*
1824  * routine to check that the specified directory is empty (for rmdir)
1825  */
1826 static int empty_dir (struct inode * inode)
1827 {
1828         unsigned long offset;
1829         struct buffer_head * bh;
1830         struct ext4_dir_entry_2 * de, * de1;
1831         struct super_block * sb;
1832         int err = 0;
1833
1834         sb = inode->i_sb;
1835         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2) ||
1836             !(bh = ext4_bread (NULL, inode, 0, 0, &err))) {
1837                 if (err)
1838                         ext4_error(inode->i_sb, __FUNCTION__,
1839                                    "error %d reading directory #%lu offset 0",
1840                                    err, inode->i_ino);
1841                 else
1842                         ext4_warning(inode->i_sb, __FUNCTION__,
1843                                      "bad directory (dir #%lu) - no data block",
1844                                      inode->i_ino);
1845                 return 1;
1846         }
1847         de = (struct ext4_dir_entry_2 *) bh->b_data;
1848         de1 = (struct ext4_dir_entry_2 *)
1849                         ((char *) de + le16_to_cpu(de->rec_len));
1850         if (le32_to_cpu(de->inode) != inode->i_ino ||
1851                         !le32_to_cpu(de1->inode) ||
1852                         strcmp (".", de->name) ||
1853                         strcmp ("..", de1->name)) {
1854                 ext4_warning (inode->i_sb, "empty_dir",
1855                               "bad directory (dir #%lu) - no `.' or `..'",
1856                               inode->i_ino);
1857                 brelse (bh);
1858                 return 1;
1859         }
1860         offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
1861         de = (struct ext4_dir_entry_2 *)
1862                         ((char *) de1 + le16_to_cpu(de1->rec_len));
1863         while (offset < inode->i_size ) {
1864                 if (!bh ||
1865                         (void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
1866                         err = 0;
1867                         brelse (bh);
1868                         bh = ext4_bread (NULL, inode,
1869                                 offset >> EXT4_BLOCK_SIZE_BITS(sb), 0, &err);
1870                         if (!bh) {
1871                                 if (err)
1872                                         ext4_error(sb, __FUNCTION__,
1873                                                    "error %d reading directory"
1874                                                    " #%lu offset %lu",
1875                                                    err, inode->i_ino, offset);
1876                                 offset += sb->s_blocksize;
1877                                 continue;
1878                         }
1879                         de = (struct ext4_dir_entry_2 *) bh->b_data;
1880                 }
1881                 if (!ext4_check_dir_entry("empty_dir", inode, de, bh, offset)) {
1882                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
1883                                                          sb->s_blocksize);
1884                         offset = (offset | (sb->s_blocksize - 1)) + 1;
1885                         continue;
1886                 }
1887                 if (le32_to_cpu(de->inode)) {
1888                         brelse (bh);
1889                         return 0;
1890                 }
1891                 offset += le16_to_cpu(de->rec_len);
1892                 de = (struct ext4_dir_entry_2 *)
1893                                 ((char *) de + le16_to_cpu(de->rec_len));
1894         }
1895         brelse (bh);
1896         return 1;
1897 }
1898
1899 /* ext4_orphan_add() links an unlinked or truncated inode into a list of
1900  * such inodes, starting at the superblock, in case we crash before the
1901  * file is closed/deleted, or in case the inode truncate spans multiple
1902  * transactions and the last transaction is not recovered after a crash.
1903  *
1904  * At filesystem recovery time, we walk this list deleting unlinked
1905  * inodes and truncating linked inodes in ext4_orphan_cleanup().
1906  */
1907 int ext4_orphan_add(handle_t *handle, struct inode *inode)
1908 {
1909         struct super_block *sb = inode->i_sb;
1910         struct ext4_iloc iloc;
1911         int err = 0, rc;
1912
1913         lock_super(sb);
1914         if (!list_empty(&EXT4_I(inode)->i_orphan))
1915                 goto out_unlock;
1916
1917         /* Orphan handling is only valid for files with data blocks
1918          * being truncated, or files being unlinked. */
1919
1920         /* @@@ FIXME: Observation from aviro:
1921          * I think I can trigger J_ASSERT in ext4_orphan_add().  We block
1922          * here (on lock_super()), so race with ext4_link() which might bump
1923          * ->i_nlink. For, say it, character device. Not a regular file,
1924          * not a directory, not a symlink and ->i_nlink > 0.
1925          */
1926         J_ASSERT ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1927                 S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
1928
1929         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1930         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1931         if (err)
1932                 goto out_unlock;
1933
1934         err = ext4_reserve_inode_write(handle, inode, &iloc);
1935         if (err)
1936                 goto out_unlock;
1937
1938         /* Insert this inode at the head of the on-disk orphan list... */
1939         NEXT_ORPHAN(inode) = le32_to_cpu(EXT4_SB(sb)->s_es->s_last_orphan);
1940         EXT4_SB(sb)->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
1941         err = ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
1942         rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
1943         if (!err)
1944                 err = rc;
1945
1946         /* Only add to the head of the in-memory list if all the
1947          * previous operations succeeded.  If the orphan_add is going to
1948          * fail (possibly taking the journal offline), we can't risk
1949          * leaving the inode on the orphan list: stray orphan-list
1950          * entries can cause panics at unmount time.
1951          *
1952          * This is safe: on error we're going to ignore the orphan list
1953          * anyway on the next recovery. */
1954         if (!err)
1955                 list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
1956
1957         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
1958         jbd_debug(4, "orphan inode %lu will point to %d\n",
1959                         inode->i_ino, NEXT_ORPHAN(inode));
1960 out_unlock:
1961         unlock_super(sb);
1962         ext4_std_error(inode->i_sb, err);
1963         return err;
1964 }
1965
1966 /*
1967  * ext4_orphan_del() removes an unlinked or truncated inode from the list
1968  * of such inodes stored on disk, because it is finally being cleaned up.
1969  */
1970 int ext4_orphan_del(handle_t *handle, struct inode *inode)
1971 {
1972         struct list_head *prev;
1973         struct ext4_inode_info *ei = EXT4_I(inode);
1974         struct ext4_sb_info *sbi;
1975         unsigned long ino_next;
1976         struct ext4_iloc iloc;
1977         int err = 0;
1978
1979         lock_super(inode->i_sb);
1980         if (list_empty(&ei->i_orphan)) {
1981                 unlock_super(inode->i_sb);
1982                 return 0;
1983         }
1984
1985         ino_next = NEXT_ORPHAN(inode);
1986         prev = ei->i_orphan.prev;
1987         sbi = EXT4_SB(inode->i_sb);
1988
1989         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
1990
1991         list_del_init(&ei->i_orphan);
1992
1993         /* If we're on an error path, we may not have a valid
1994          * transaction handle with which to update the orphan list on
1995          * disk, but we still need to remove the inode from the linked
1996          * list in memory. */
1997         if (!handle)
1998                 goto out;
1999
2000         err = ext4_reserve_inode_write(handle, inode, &iloc);
2001         if (err)
2002                 goto out_err;
2003
2004         if (prev == &sbi->s_orphan) {
2005                 jbd_debug(4, "superblock will point to %lu\n", ino_next);
2006                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2007                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2008                 if (err)
2009                         goto out_brelse;
2010                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2011                 err = ext4_journal_dirty_metadata(handle, sbi->s_sbh);
2012         } else {
2013                 struct ext4_iloc iloc2;
2014                 struct inode *i_prev =
2015                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2016
2017                 jbd_debug(4, "orphan inode %lu will point to %lu\n",
2018                           i_prev->i_ino, ino_next);
2019                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2020                 if (err)
2021                         goto out_brelse;
2022                 NEXT_ORPHAN(i_prev) = ino_next;
2023                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2024         }
2025         if (err)
2026                 goto out_brelse;
2027         NEXT_ORPHAN(inode) = 0;
2028         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2029
2030 out_err:
2031         ext4_std_error(inode->i_sb, err);
2032 out:
2033         unlock_super(inode->i_sb);
2034         return err;
2035
2036 out_brelse:
2037         brelse(iloc.bh);
2038         goto out_err;
2039 }
2040
2041 static int ext4_rmdir (struct inode * dir, struct dentry *dentry)
2042 {
2043         int retval;
2044         struct inode * inode;
2045         struct buffer_head * bh;
2046         struct ext4_dir_entry_2 * de;
2047         handle_t *handle;
2048
2049         /* Initialize quotas before so that eventual writes go in
2050          * separate transaction */
2051         DQUOT_INIT(dentry->d_inode);
2052         handle = ext4_journal_start(dir, EXT4_DELETE_TRANS_BLOCKS(dir->i_sb));
2053         if (IS_ERR(handle))
2054                 return PTR_ERR(handle);
2055
2056         retval = -ENOENT;
2057         bh = ext4_find_entry (dentry, &de);
2058         if (!bh)
2059                 goto end_rmdir;
2060
2061         if (IS_DIRSYNC(dir))
2062                 handle->h_sync = 1;
2063
2064         inode = dentry->d_inode;
2065
2066         retval = -EIO;
2067         if (le32_to_cpu(de->inode) != inode->i_ino)
2068                 goto end_rmdir;
2069
2070         retval = -ENOTEMPTY;
2071         if (!empty_dir (inode))
2072                 goto end_rmdir;
2073
2074         retval = ext4_delete_entry(handle, dir, de, bh);
2075         if (retval)
2076                 goto end_rmdir;
2077         if (!EXT4_DIR_LINK_EMPTY(inode))
2078                 ext4_warning (inode->i_sb, "ext4_rmdir",
2079                               "empty directory has too many links (%d)",
2080                               inode->i_nlink);
2081         inode->i_version++;
2082         clear_nlink(inode);
2083         /* There's no need to set i_disksize: the fact that i_nlink is
2084          * zero will ensure that the right thing happens during any
2085          * recovery. */
2086         inode->i_size = 0;
2087         ext4_orphan_add(handle, inode);
2088         inode->i_ctime = dir->i_ctime = dir->i_mtime = ext4_current_time(inode);
2089         ext4_mark_inode_dirty(handle, inode);
2090         ext4_dec_count(handle, dir);
2091         ext4_update_dx_flag(dir);
2092         ext4_mark_inode_dirty(handle, dir);
2093
2094 end_rmdir:
2095         ext4_journal_stop(handle);
2096         brelse (bh);
2097         return retval;
2098 }
2099
2100 static int ext4_unlink(struct inode * dir, struct dentry *dentry)
2101 {
2102         int retval;
2103         struct inode * inode;
2104         struct buffer_head * bh;
2105         struct ext4_dir_entry_2 * de;
2106         handle_t *handle;
2107
2108         /* Initialize quotas before so that eventual writes go
2109          * in separate transaction */
2110         DQUOT_INIT(dentry->d_inode);
2111         handle = ext4_journal_start(dir, EXT4_DELETE_TRANS_BLOCKS(dir->i_sb));
2112         if (IS_ERR(handle))
2113                 return PTR_ERR(handle);
2114
2115         if (IS_DIRSYNC(dir))
2116                 handle->h_sync = 1;
2117
2118         retval = -ENOENT;
2119         bh = ext4_find_entry (dentry, &de);
2120         if (!bh)
2121                 goto end_unlink;
2122
2123         inode = dentry->d_inode;
2124
2125         retval = -EIO;
2126         if (le32_to_cpu(de->inode) != inode->i_ino)
2127                 goto end_unlink;
2128
2129         if (!inode->i_nlink) {
2130                 ext4_warning (inode->i_sb, "ext4_unlink",
2131                               "Deleting nonexistent file (%lu), %d",
2132                               inode->i_ino, inode->i_nlink);
2133                 inode->i_nlink = 1;
2134         }
2135         retval = ext4_delete_entry(handle, dir, de, bh);
2136         if (retval)
2137                 goto end_unlink;
2138         dir->i_ctime = dir->i_mtime = ext4_current_time(dir);
2139         ext4_update_dx_flag(dir);
2140         ext4_mark_inode_dirty(handle, dir);
2141         ext4_dec_count(handle, inode);
2142         if (!inode->i_nlink)
2143                 ext4_orphan_add(handle, inode);
2144         inode->i_ctime = ext4_current_time(inode);
2145         ext4_mark_inode_dirty(handle, inode);
2146         retval = 0;
2147
2148 end_unlink:
2149         ext4_journal_stop(handle);
2150         brelse (bh);
2151         return retval;
2152 }
2153
2154 static int ext4_symlink (struct inode * dir,
2155                 struct dentry *dentry, const char * symname)
2156 {
2157         handle_t *handle;
2158         struct inode * inode;
2159         int l, err, retries = 0;
2160
2161         l = strlen(symname)+1;
2162         if (l > dir->i_sb->s_blocksize)
2163                 return -ENAMETOOLONG;
2164
2165 retry:
2166         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2167                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 5 +
2168                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
2169         if (IS_ERR(handle))
2170                 return PTR_ERR(handle);
2171
2172         if (IS_DIRSYNC(dir))
2173                 handle->h_sync = 1;
2174
2175         inode = ext4_new_inode (handle, dir, S_IFLNK|S_IRWXUGO);
2176         err = PTR_ERR(inode);
2177         if (IS_ERR(inode))
2178                 goto out_stop;
2179
2180         if (l > sizeof (EXT4_I(inode)->i_data)) {
2181                 inode->i_op = &ext4_symlink_inode_operations;
2182                 ext4_set_aops(inode);
2183                 /*
2184                  * page_symlink() calls into ext4_prepare/commit_write.
2185                  * We have a transaction open.  All is sweetness.  It also sets
2186                  * i_size in generic_commit_write().
2187                  */
2188                 err = __page_symlink(inode, symname, l,
2189                                 mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
2190                 if (err) {
2191                         ext4_dec_count(handle, inode);
2192                         ext4_mark_inode_dirty(handle, inode);
2193                         iput (inode);
2194                         goto out_stop;
2195                 }
2196         } else {
2197                 inode->i_op = &ext4_fast_symlink_inode_operations;
2198                 memcpy((char*)&EXT4_I(inode)->i_data,symname,l);
2199                 inode->i_size = l-1;
2200         }
2201         EXT4_I(inode)->i_disksize = inode->i_size;
2202         err = ext4_add_nondir(handle, dentry, inode);
2203 out_stop:
2204         ext4_journal_stop(handle);
2205         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2206                 goto retry;
2207         return err;
2208 }
2209
2210 static int ext4_link (struct dentry * old_dentry,
2211                 struct inode * dir, struct dentry *dentry)
2212 {
2213         handle_t *handle;
2214         struct inode *inode = old_dentry->d_inode;
2215         int err, retries = 0;
2216
2217         if (EXT4_DIR_LINK_MAX(inode))
2218                 return -EMLINK;
2219
2220         /*
2221          * Return -ENOENT if we've raced with unlink and i_nlink is 0.  Doing
2222          * otherwise has the potential to corrupt the orphan inode list.
2223          */
2224         if (inode->i_nlink == 0)
2225                 return -ENOENT;
2226
2227 retry:
2228         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2229                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS);
2230         if (IS_ERR(handle))
2231                 return PTR_ERR(handle);
2232
2233         if (IS_DIRSYNC(dir))
2234                 handle->h_sync = 1;
2235
2236         inode->i_ctime = ext4_current_time(inode);
2237         ext4_inc_count(handle, inode);
2238         atomic_inc(&inode->i_count);
2239
2240         err = ext4_add_nondir(handle, dentry, inode);
2241         ext4_journal_stop(handle);
2242         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2243                 goto retry;
2244         return err;
2245 }
2246
2247 #define PARENT_INO(buffer) \
2248         ((struct ext4_dir_entry_2 *) ((char *) buffer + \
2249         le16_to_cpu(((struct ext4_dir_entry_2 *) buffer)->rec_len)))->inode
2250
2251 /*
2252  * Anybody can rename anything with this: the permission checks are left to the
2253  * higher-level routines.
2254  */
2255 static int ext4_rename (struct inode * old_dir, struct dentry *old_dentry,
2256                            struct inode * new_dir,struct dentry *new_dentry)
2257 {
2258         handle_t *handle;
2259         struct inode * old_inode, * new_inode;
2260         struct buffer_head * old_bh, * new_bh, * dir_bh;
2261         struct ext4_dir_entry_2 * old_de, * new_de;
2262         int retval;
2263
2264         old_bh = new_bh = dir_bh = NULL;
2265
2266         /* Initialize quotas before so that eventual writes go
2267          * in separate transaction */
2268         if (new_dentry->d_inode)
2269                 DQUOT_INIT(new_dentry->d_inode);
2270         handle = ext4_journal_start(old_dir, 2 *
2271                                         EXT4_DATA_TRANS_BLOCKS(old_dir->i_sb) +
2272                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
2273         if (IS_ERR(handle))
2274                 return PTR_ERR(handle);
2275
2276         if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
2277                 handle->h_sync = 1;
2278
2279         old_bh = ext4_find_entry (old_dentry, &old_de);
2280         /*
2281          *  Check for inode number is _not_ due to possible IO errors.
2282          *  We might rmdir the source, keep it as pwd of some process
2283          *  and merrily kill the link to whatever was created under the
2284          *  same name. Goodbye sticky bit ;-<
2285          */
2286         old_inode = old_dentry->d_inode;
2287         retval = -ENOENT;
2288         if (!old_bh || le32_to_cpu(old_de->inode) != old_inode->i_ino)
2289                 goto end_rename;
2290
2291         new_inode = new_dentry->d_inode;
2292         new_bh = ext4_find_entry (new_dentry, &new_de);
2293         if (new_bh) {
2294                 if (!new_inode) {
2295                         brelse (new_bh);
2296                         new_bh = NULL;
2297                 }
2298         }
2299         if (S_ISDIR(old_inode->i_mode)) {
2300                 if (new_inode) {
2301                         retval = -ENOTEMPTY;
2302                         if (!empty_dir (new_inode))
2303                                 goto end_rename;
2304                 }
2305                 retval = -EIO;
2306                 dir_bh = ext4_bread (handle, old_inode, 0, 0, &retval);
2307                 if (!dir_bh)
2308                         goto end_rename;
2309                 if (le32_to_cpu(PARENT_INO(dir_bh->b_data)) != old_dir->i_ino)
2310                         goto end_rename;
2311                 retval = -EMLINK;
2312                 if (!new_inode && new_dir!=old_dir &&
2313                                 new_dir->i_nlink >= EXT4_LINK_MAX)
2314                         goto end_rename;
2315         }
2316         if (!new_bh) {
2317                 retval = ext4_add_entry (handle, new_dentry, old_inode);
2318                 if (retval)
2319                         goto end_rename;
2320         } else {
2321                 BUFFER_TRACE(new_bh, "get write access");
2322                 ext4_journal_get_write_access(handle, new_bh);
2323                 new_de->inode = cpu_to_le32(old_inode->i_ino);
2324                 if (EXT4_HAS_INCOMPAT_FEATURE(new_dir->i_sb,
2325                                               EXT4_FEATURE_INCOMPAT_FILETYPE))
2326                         new_de->file_type = old_de->file_type;
2327                 new_dir->i_version++;
2328                 BUFFER_TRACE(new_bh, "call ext4_journal_dirty_metadata");
2329                 ext4_journal_dirty_metadata(handle, new_bh);
2330                 brelse(new_bh);
2331                 new_bh = NULL;
2332         }
2333
2334         /*
2335          * Like most other Unix systems, set the ctime for inodes on a
2336          * rename.
2337          */
2338         old_inode->i_ctime = ext4_current_time(old_inode);
2339         ext4_mark_inode_dirty(handle, old_inode);
2340
2341         /*
2342          * ok, that's it
2343          */
2344         if (le32_to_cpu(old_de->inode) != old_inode->i_ino ||
2345             old_de->name_len != old_dentry->d_name.len ||
2346             strncmp(old_de->name, old_dentry->d_name.name, old_de->name_len) ||
2347             (retval = ext4_delete_entry(handle, old_dir,
2348                                         old_de, old_bh)) == -ENOENT) {
2349                 /* old_de could have moved from under us during htree split, so
2350                  * make sure that we are deleting the right entry.  We might
2351                  * also be pointing to a stale entry in the unused part of
2352                  * old_bh so just checking inum and the name isn't enough. */
2353                 struct buffer_head *old_bh2;
2354                 struct ext4_dir_entry_2 *old_de2;
2355
2356                 old_bh2 = ext4_find_entry(old_dentry, &old_de2);
2357                 if (old_bh2) {
2358                         retval = ext4_delete_entry(handle, old_dir,
2359                                                    old_de2, old_bh2);
2360                         brelse(old_bh2);
2361                 }
2362         }
2363         if (retval) {
2364                 ext4_warning(old_dir->i_sb, "ext4_rename",
2365                                 "Deleting old file (%lu), %d, error=%d",
2366                                 old_dir->i_ino, old_dir->i_nlink, retval);
2367         }
2368
2369         if (new_inode) {
2370                 ext4_dec_count(handle, new_inode);
2371                 new_inode->i_ctime = ext4_current_time(new_inode);
2372         }
2373         old_dir->i_ctime = old_dir->i_mtime = ext4_current_time(old_dir);
2374         ext4_update_dx_flag(old_dir);
2375         if (dir_bh) {
2376                 BUFFER_TRACE(dir_bh, "get_write_access");
2377                 ext4_journal_get_write_access(handle, dir_bh);
2378                 PARENT_INO(dir_bh->b_data) = cpu_to_le32(new_dir->i_ino);
2379                 BUFFER_TRACE(dir_bh, "call ext4_journal_dirty_metadata");
2380                 ext4_journal_dirty_metadata(handle, dir_bh);
2381                 ext4_dec_count(handle, old_dir);
2382                 if (new_inode) {
2383                         /* checked empty_dir above, can't have another parent,
2384                          * ext3_dec_count() won't work for many-linked dirs */
2385                         new_inode->i_nlink = 0;
2386                 } else {
2387                         ext4_inc_count(handle, new_dir);
2388                         ext4_update_dx_flag(new_dir);
2389                         ext4_mark_inode_dirty(handle, new_dir);
2390                 }
2391         }
2392         ext4_mark_inode_dirty(handle, old_dir);
2393         if (new_inode) {
2394                 ext4_mark_inode_dirty(handle, new_inode);
2395                 if (!new_inode->i_nlink)
2396                         ext4_orphan_add(handle, new_inode);
2397         }
2398         retval = 0;
2399
2400 end_rename:
2401         brelse (dir_bh);
2402         brelse (old_bh);
2403         brelse (new_bh);
2404         ext4_journal_stop(handle);
2405         return retval;
2406 }
2407
2408 /*
2409  * directories can handle most operations...
2410  */
2411 const struct inode_operations ext4_dir_inode_operations = {
2412         .create         = ext4_create,
2413         .lookup         = ext4_lookup,
2414         .link           = ext4_link,
2415         .unlink         = ext4_unlink,
2416         .symlink        = ext4_symlink,
2417         .mkdir          = ext4_mkdir,
2418         .rmdir          = ext4_rmdir,
2419         .mknod          = ext4_mknod,
2420         .rename         = ext4_rename,
2421         .setattr        = ext4_setattr,
2422 #ifdef CONFIG_EXT4DEV_FS_XATTR
2423         .setxattr       = generic_setxattr,
2424         .getxattr       = generic_getxattr,
2425         .listxattr      = ext4_listxattr,
2426         .removexattr    = generic_removexattr,
2427 #endif
2428         .permission     = ext4_permission,
2429 };
2430
2431 const struct inode_operations ext4_special_inode_operations = {
2432         .setattr        = ext4_setattr,
2433 #ifdef CONFIG_EXT4DEV_FS_XATTR
2434         .setxattr       = generic_setxattr,
2435         .getxattr       = generic_getxattr,
2436         .listxattr      = ext4_listxattr,
2437         .removexattr    = generic_removexattr,
2438 #endif
2439         .permission     = ext4_permission,
2440 };