Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
[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/fcntl.h>
32 #include <linux/stat.h>
33 #include <linux/string.h>
34 #include <linux/quotaops.h>
35 #include <linux/buffer_head.h>
36 #include <linux/bio.h>
37 #include "ext4.h"
38 #include "ext4_jbd2.h"
39
40 #include "xattr.h"
41 #include "acl.h"
42
43 #include <trace/events/ext4.h>
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
51 static struct buffer_head *ext4_append(handle_t *handle,
52                                         struct inode *inode,
53                                         ext4_lblk_t *block)
54 {
55         struct buffer_head *bh;
56         int err;
57
58         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
59                      ((inode->i_size >> 10) >=
60                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
61                 return ERR_PTR(-ENOSPC);
62
63         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
64
65         bh = ext4_bread(handle, inode, *block, 1);
66         if (IS_ERR(bh))
67                 return bh;
68         inode->i_size += inode->i_sb->s_blocksize;
69         EXT4_I(inode)->i_disksize = inode->i_size;
70         BUFFER_TRACE(bh, "get_write_access");
71         err = ext4_journal_get_write_access(handle, bh);
72         if (err) {
73                 brelse(bh);
74                 ext4_std_error(inode->i_sb, err);
75                 return ERR_PTR(err);
76         }
77         return bh;
78 }
79
80 static int ext4_dx_csum_verify(struct inode *inode,
81                                struct ext4_dir_entry *dirent);
82
83 typedef enum {
84         EITHER, INDEX, DIRENT
85 } dirblock_type_t;
86
87 #define ext4_read_dirblock(inode, block, type) \
88         __ext4_read_dirblock((inode), (block), (type), __LINE__)
89
90 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
91                                               ext4_lblk_t block,
92                                               dirblock_type_t type,
93                                               unsigned int line)
94 {
95         struct buffer_head *bh;
96         struct ext4_dir_entry *dirent;
97         int is_dx_block = 0;
98
99         bh = ext4_bread(NULL, inode, block, 0);
100         if (IS_ERR(bh)) {
101                 __ext4_warning(inode->i_sb, __func__, line,
102                                "error %ld reading directory block "
103                                "(ino %lu, block %lu)", PTR_ERR(bh), inode->i_ino,
104                                (unsigned long) block);
105
106                 return bh;
107         }
108         if (!bh) {
109                 ext4_error_inode(inode, __func__, line, block, "Directory hole found");
110                 return ERR_PTR(-EIO);
111         }
112         dirent = (struct ext4_dir_entry *) bh->b_data;
113         /* Determine whether or not we have an index block */
114         if (is_dx(inode)) {
115                 if (block == 0)
116                         is_dx_block = 1;
117                 else if (ext4_rec_len_from_disk(dirent->rec_len,
118                                                 inode->i_sb->s_blocksize) ==
119                          inode->i_sb->s_blocksize)
120                         is_dx_block = 1;
121         }
122         if (!is_dx_block && type == INDEX) {
123                 ext4_error_inode(inode, __func__, line, block,
124                        "directory leaf block found instead of index block");
125                 return ERR_PTR(-EIO);
126         }
127         if (!ext4_has_metadata_csum(inode->i_sb) ||
128             buffer_verified(bh))
129                 return bh;
130
131         /*
132          * An empty leaf block can get mistaken for a index block; for
133          * this reason, we can only check the index checksum when the
134          * caller is sure it should be an index block.
135          */
136         if (is_dx_block && type == INDEX) {
137                 if (ext4_dx_csum_verify(inode, dirent))
138                         set_buffer_verified(bh);
139                 else {
140                         ext4_error_inode(inode, __func__, line, block,
141                                 "Directory index failed checksum");
142                         brelse(bh);
143                         return ERR_PTR(-EIO);
144                 }
145         }
146         if (!is_dx_block) {
147                 if (ext4_dirent_csum_verify(inode, dirent))
148                         set_buffer_verified(bh);
149                 else {
150                         ext4_error_inode(inode, __func__, line, block,
151                                 "Directory block failed checksum");
152                         brelse(bh);
153                         return ERR_PTR(-EIO);
154                 }
155         }
156         return bh;
157 }
158
159 #ifndef assert
160 #define assert(test) J_ASSERT(test)
161 #endif
162
163 #ifdef DX_DEBUG
164 #define dxtrace(command) command
165 #else
166 #define dxtrace(command)
167 #endif
168
169 struct fake_dirent
170 {
171         __le32 inode;
172         __le16 rec_len;
173         u8 name_len;
174         u8 file_type;
175 };
176
177 struct dx_countlimit
178 {
179         __le16 limit;
180         __le16 count;
181 };
182
183 struct dx_entry
184 {
185         __le32 hash;
186         __le32 block;
187 };
188
189 /*
190  * dx_root_info is laid out so that if it should somehow get overlaid by a
191  * dirent the two low bits of the hash version will be zero.  Therefore, the
192  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
193  */
194
195 struct dx_root
196 {
197         struct fake_dirent dot;
198         char dot_name[4];
199         struct fake_dirent dotdot;
200         char dotdot_name[4];
201         struct dx_root_info
202         {
203                 __le32 reserved_zero;
204                 u8 hash_version;
205                 u8 info_length; /* 8 */
206                 u8 indirect_levels;
207                 u8 unused_flags;
208         }
209         info;
210         struct dx_entry entries[0];
211 };
212
213 struct dx_node
214 {
215         struct fake_dirent fake;
216         struct dx_entry entries[0];
217 };
218
219
220 struct dx_frame
221 {
222         struct buffer_head *bh;
223         struct dx_entry *entries;
224         struct dx_entry *at;
225 };
226
227 struct dx_map_entry
228 {
229         u32 hash;
230         u16 offs;
231         u16 size;
232 };
233
234 /*
235  * This goes at the end of each htree block.
236  */
237 struct dx_tail {
238         u32 dt_reserved;
239         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
240 };
241
242 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
243 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
244 static inline unsigned dx_get_hash(struct dx_entry *entry);
245 static void dx_set_hash(struct dx_entry *entry, unsigned value);
246 static unsigned dx_get_count(struct dx_entry *entries);
247 static unsigned dx_get_limit(struct dx_entry *entries);
248 static void dx_set_count(struct dx_entry *entries, unsigned value);
249 static void dx_set_limit(struct dx_entry *entries, unsigned value);
250 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
251 static unsigned dx_node_limit(struct inode *dir);
252 static struct dx_frame *dx_probe(const struct qstr *d_name,
253                                  struct inode *dir,
254                                  struct dx_hash_info *hinfo,
255                                  struct dx_frame *frame);
256 static void dx_release(struct dx_frame *frames);
257 static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
258                        struct dx_hash_info *hinfo, struct dx_map_entry map[]);
259 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
260 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
261                 struct dx_map_entry *offsets, int count, unsigned blocksize);
262 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
263 static void dx_insert_block(struct dx_frame *frame,
264                                         u32 hash, ext4_lblk_t block);
265 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
266                                  struct dx_frame *frame,
267                                  struct dx_frame *frames,
268                                  __u32 *start_hash);
269 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
270                 const struct qstr *d_name,
271                 struct ext4_dir_entry_2 **res_dir);
272 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
273                              struct inode *inode);
274
275 /* checksumming functions */
276 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
277                             unsigned int blocksize)
278 {
279         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
280         t->det_rec_len = ext4_rec_len_to_disk(
281                         sizeof(struct ext4_dir_entry_tail), blocksize);
282         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
283 }
284
285 /* Walk through a dirent block to find a checksum "dirent" at the tail */
286 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
287                                                    struct ext4_dir_entry *de)
288 {
289         struct ext4_dir_entry_tail *t;
290
291 #ifdef PARANOID
292         struct ext4_dir_entry *d, *top;
293
294         d = de;
295         top = (struct ext4_dir_entry *)(((void *)de) +
296                 (EXT4_BLOCK_SIZE(inode->i_sb) -
297                 sizeof(struct ext4_dir_entry_tail)));
298         while (d < top && d->rec_len)
299                 d = (struct ext4_dir_entry *)(((void *)d) +
300                     le16_to_cpu(d->rec_len));
301
302         if (d != top)
303                 return NULL;
304
305         t = (struct ext4_dir_entry_tail *)d;
306 #else
307         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
308 #endif
309
310         if (t->det_reserved_zero1 ||
311             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
312             t->det_reserved_zero2 ||
313             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
314                 return NULL;
315
316         return t;
317 }
318
319 static __le32 ext4_dirent_csum(struct inode *inode,
320                                struct ext4_dir_entry *dirent, int size)
321 {
322         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
323         struct ext4_inode_info *ei = EXT4_I(inode);
324         __u32 csum;
325
326         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
327         return cpu_to_le32(csum);
328 }
329
330 static void warn_no_space_for_csum(struct inode *inode)
331 {
332         ext4_warning(inode->i_sb, "no space in directory inode %lu leaf for "
333                      "checksum.  Please run e2fsck -D.", inode->i_ino);
334 }
335
336 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
337 {
338         struct ext4_dir_entry_tail *t;
339
340         if (!ext4_has_metadata_csum(inode->i_sb))
341                 return 1;
342
343         t = get_dirent_tail(inode, dirent);
344         if (!t) {
345                 warn_no_space_for_csum(inode);
346                 return 0;
347         }
348
349         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
350                                                 (void *)t - (void *)dirent))
351                 return 0;
352
353         return 1;
354 }
355
356 static void ext4_dirent_csum_set(struct inode *inode,
357                                  struct ext4_dir_entry *dirent)
358 {
359         struct ext4_dir_entry_tail *t;
360
361         if (!ext4_has_metadata_csum(inode->i_sb))
362                 return;
363
364         t = get_dirent_tail(inode, dirent);
365         if (!t) {
366                 warn_no_space_for_csum(inode);
367                 return;
368         }
369
370         t->det_checksum = ext4_dirent_csum(inode, dirent,
371                                            (void *)t - (void *)dirent);
372 }
373
374 int ext4_handle_dirty_dirent_node(handle_t *handle,
375                                   struct inode *inode,
376                                   struct buffer_head *bh)
377 {
378         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
379         return ext4_handle_dirty_metadata(handle, inode, bh);
380 }
381
382 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
383                                                struct ext4_dir_entry *dirent,
384                                                int *offset)
385 {
386         struct ext4_dir_entry *dp;
387         struct dx_root_info *root;
388         int count_offset;
389
390         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
391                 count_offset = 8;
392         else if (le16_to_cpu(dirent->rec_len) == 12) {
393                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
394                 if (le16_to_cpu(dp->rec_len) !=
395                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
396                         return NULL;
397                 root = (struct dx_root_info *)(((void *)dp + 12));
398                 if (root->reserved_zero ||
399                     root->info_length != sizeof(struct dx_root_info))
400                         return NULL;
401                 count_offset = 32;
402         } else
403                 return NULL;
404
405         if (offset)
406                 *offset = count_offset;
407         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
408 }
409
410 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
411                            int count_offset, int count, struct dx_tail *t)
412 {
413         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
414         struct ext4_inode_info *ei = EXT4_I(inode);
415         __u32 csum;
416         __le32 save_csum;
417         int size;
418
419         size = count_offset + (count * sizeof(struct dx_entry));
420         save_csum = t->dt_checksum;
421         t->dt_checksum = 0;
422         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
423         csum = ext4_chksum(sbi, csum, (__u8 *)t, sizeof(struct dx_tail));
424         t->dt_checksum = save_csum;
425
426         return cpu_to_le32(csum);
427 }
428
429 static int ext4_dx_csum_verify(struct inode *inode,
430                                struct ext4_dir_entry *dirent)
431 {
432         struct dx_countlimit *c;
433         struct dx_tail *t;
434         int count_offset, limit, count;
435
436         if (!ext4_has_metadata_csum(inode->i_sb))
437                 return 1;
438
439         c = get_dx_countlimit(inode, dirent, &count_offset);
440         if (!c) {
441                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
442                 return 1;
443         }
444         limit = le16_to_cpu(c->limit);
445         count = le16_to_cpu(c->count);
446         if (count_offset + (limit * sizeof(struct dx_entry)) >
447             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
448                 warn_no_space_for_csum(inode);
449                 return 1;
450         }
451         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
452
453         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
454                                             count, t))
455                 return 0;
456         return 1;
457 }
458
459 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
460 {
461         struct dx_countlimit *c;
462         struct dx_tail *t;
463         int count_offset, limit, count;
464
465         if (!ext4_has_metadata_csum(inode->i_sb))
466                 return;
467
468         c = get_dx_countlimit(inode, dirent, &count_offset);
469         if (!c) {
470                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
471                 return;
472         }
473         limit = le16_to_cpu(c->limit);
474         count = le16_to_cpu(c->count);
475         if (count_offset + (limit * sizeof(struct dx_entry)) >
476             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
477                 warn_no_space_for_csum(inode);
478                 return;
479         }
480         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
481
482         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
483 }
484
485 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
486                                             struct inode *inode,
487                                             struct buffer_head *bh)
488 {
489         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
490         return ext4_handle_dirty_metadata(handle, inode, bh);
491 }
492
493 /*
494  * p is at least 6 bytes before the end of page
495  */
496 static inline struct ext4_dir_entry_2 *
497 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
498 {
499         return (struct ext4_dir_entry_2 *)((char *)p +
500                 ext4_rec_len_from_disk(p->rec_len, blocksize));
501 }
502
503 /*
504  * Future: use high four bits of block for coalesce-on-delete flags
505  * Mask them off for now.
506  */
507
508 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
509 {
510         return le32_to_cpu(entry->block) & 0x00ffffff;
511 }
512
513 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
514 {
515         entry->block = cpu_to_le32(value);
516 }
517
518 static inline unsigned dx_get_hash(struct dx_entry *entry)
519 {
520         return le32_to_cpu(entry->hash);
521 }
522
523 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
524 {
525         entry->hash = cpu_to_le32(value);
526 }
527
528 static inline unsigned dx_get_count(struct dx_entry *entries)
529 {
530         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
531 }
532
533 static inline unsigned dx_get_limit(struct dx_entry *entries)
534 {
535         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
536 }
537
538 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
539 {
540         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
541 }
542
543 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
544 {
545         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
546 }
547
548 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
549 {
550         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
551                 EXT4_DIR_REC_LEN(2) - infosize;
552
553         if (ext4_has_metadata_csum(dir->i_sb))
554                 entry_space -= sizeof(struct dx_tail);
555         return entry_space / sizeof(struct dx_entry);
556 }
557
558 static inline unsigned dx_node_limit(struct inode *dir)
559 {
560         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
561
562         if (ext4_has_metadata_csum(dir->i_sb))
563                 entry_space -= sizeof(struct dx_tail);
564         return entry_space / sizeof(struct dx_entry);
565 }
566
567 /*
568  * Debug
569  */
570 #ifdef DX_DEBUG
571 static void dx_show_index(char * label, struct dx_entry *entries)
572 {
573         int i, n = dx_get_count (entries);
574         printk(KERN_DEBUG "%s index ", label);
575         for (i = 0; i < n; i++) {
576                 printk("%x->%lu ", i ? dx_get_hash(entries + i) :
577                                 0, (unsigned long)dx_get_block(entries + i));
578         }
579         printk("\n");
580 }
581
582 struct stats
583 {
584         unsigned names;
585         unsigned space;
586         unsigned bcount;
587 };
588
589 static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext4_dir_entry_2 *de,
590                                  int size, int show_names)
591 {
592         unsigned names = 0, space = 0;
593         char *base = (char *) de;
594         struct dx_hash_info h = *hinfo;
595
596         printk("names: ");
597         while ((char *) de < base + size)
598         {
599                 if (de->inode)
600                 {
601                         if (show_names)
602                         {
603                                 int len = de->name_len;
604                                 char *name = de->name;
605                                 while (len--) printk("%c", *name++);
606                                 ext4fs_dirhash(de->name, de->name_len, &h);
607                                 printk(":%x.%u ", h.hash,
608                                        (unsigned) ((char *) de - base));
609                         }
610                         space += EXT4_DIR_REC_LEN(de->name_len);
611                         names++;
612                 }
613                 de = ext4_next_entry(de, size);
614         }
615         printk("(%i)\n", names);
616         return (struct stats) { names, space, 1 };
617 }
618
619 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
620                              struct dx_entry *entries, int levels)
621 {
622         unsigned blocksize = dir->i_sb->s_blocksize;
623         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
624         unsigned bcount = 0;
625         struct buffer_head *bh;
626         int err;
627         printk("%i indexed blocks...\n", count);
628         for (i = 0; i < count; i++, entries++)
629         {
630                 ext4_lblk_t block = dx_get_block(entries);
631                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
632                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
633                 struct stats stats;
634                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
635                 bh = ext4_bread(NULL,dir, block, 0);
636                 if (!bh || IS_ERR(bh))
637                         continue;
638                 stats = levels?
639                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
640                    dx_show_leaf(hinfo, (struct ext4_dir_entry_2 *) bh->b_data, blocksize, 0);
641                 names += stats.names;
642                 space += stats.space;
643                 bcount += stats.bcount;
644                 brelse(bh);
645         }
646         if (bcount)
647                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
648                        levels ? "" : "   ", names, space/bcount,
649                        (space/bcount)*100/blocksize);
650         return (struct stats) { names, space, bcount};
651 }
652 #endif /* DX_DEBUG */
653
654 /*
655  * Probe for a directory leaf block to search.
656  *
657  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
658  * error in the directory index, and the caller should fall back to
659  * searching the directory normally.  The callers of dx_probe **MUST**
660  * check for this error code, and make sure it never gets reflected
661  * back to userspace.
662  */
663 static struct dx_frame *
664 dx_probe(const struct qstr *d_name, struct inode *dir,
665          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
666 {
667         unsigned count, indirect;
668         struct dx_entry *at, *entries, *p, *q, *m;
669         struct dx_root *root;
670         struct dx_frame *frame = frame_in;
671         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
672         u32 hash;
673
674         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
675         if (IS_ERR(frame->bh))
676                 return (struct dx_frame *) frame->bh;
677
678         root = (struct dx_root *) frame->bh->b_data;
679         if (root->info.hash_version != DX_HASH_TEA &&
680             root->info.hash_version != DX_HASH_HALF_MD4 &&
681             root->info.hash_version != DX_HASH_LEGACY) {
682                 ext4_warning(dir->i_sb, "Unrecognised inode hash code %d",
683                              root->info.hash_version);
684                 goto fail;
685         }
686         hinfo->hash_version = root->info.hash_version;
687         if (hinfo->hash_version <= DX_HASH_TEA)
688                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
689         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
690         if (d_name)
691                 ext4fs_dirhash(d_name->name, d_name->len, hinfo);
692         hash = hinfo->hash;
693
694         if (root->info.unused_flags & 1) {
695                 ext4_warning(dir->i_sb, "Unimplemented inode hash flags: %#06x",
696                              root->info.unused_flags);
697                 goto fail;
698         }
699
700         if ((indirect = root->info.indirect_levels) > 1) {
701                 ext4_warning(dir->i_sb, "Unimplemented inode hash depth: %#06x",
702                              root->info.indirect_levels);
703                 goto fail;
704         }
705
706         entries = (struct dx_entry *) (((char *)&root->info) +
707                                        root->info.info_length);
708
709         if (dx_get_limit(entries) != dx_root_limit(dir,
710                                                    root->info.info_length)) {
711                 ext4_warning(dir->i_sb, "dx entry: limit != root limit");
712                 goto fail;
713         }
714
715         dxtrace(printk("Look up %x", hash));
716         while (1) {
717                 count = dx_get_count(entries);
718                 if (!count || count > dx_get_limit(entries)) {
719                         ext4_warning(dir->i_sb,
720                                      "dx entry: no count or count > limit");
721                         goto fail;
722                 }
723
724                 p = entries + 1;
725                 q = entries + count - 1;
726                 while (p <= q) {
727                         m = p + (q - p)/2;
728                         dxtrace(printk("."));
729                         if (dx_get_hash(m) > hash)
730                                 q = m - 1;
731                         else
732                                 p = m + 1;
733                 }
734
735                 if (0) { // linear search cross check
736                         unsigned n = count - 1;
737                         at = entries;
738                         while (n--)
739                         {
740                                 dxtrace(printk(","));
741                                 if (dx_get_hash(++at) > hash)
742                                 {
743                                         at--;
744                                         break;
745                                 }
746                         }
747                         assert (at == p - 1);
748                 }
749
750                 at = p - 1;
751                 dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at)));
752                 frame->entries = entries;
753                 frame->at = at;
754                 if (!indirect--)
755                         return frame;
756                 frame++;
757                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
758                 if (IS_ERR(frame->bh)) {
759                         ret_err = (struct dx_frame *) frame->bh;
760                         frame->bh = NULL;
761                         goto fail;
762                 }
763                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
764
765                 if (dx_get_limit(entries) != dx_node_limit (dir)) {
766                         ext4_warning(dir->i_sb,
767                                      "dx entry: limit != node limit");
768                         goto fail;
769                 }
770         }
771 fail:
772         while (frame >= frame_in) {
773                 brelse(frame->bh);
774                 frame--;
775         }
776         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
777                 ext4_warning(dir->i_sb,
778                              "Corrupt dir inode %lu, running e2fsck is "
779                              "recommended.", dir->i_ino);
780         return ret_err;
781 }
782
783 static void dx_release (struct dx_frame *frames)
784 {
785         if (frames[0].bh == NULL)
786                 return;
787
788         if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels)
789                 brelse(frames[1].bh);
790         brelse(frames[0].bh);
791 }
792
793 /*
794  * This function increments the frame pointer to search the next leaf
795  * block, and reads in the necessary intervening nodes if the search
796  * should be necessary.  Whether or not the search is necessary is
797  * controlled by the hash parameter.  If the hash value is even, then
798  * the search is only continued if the next block starts with that
799  * hash value.  This is used if we are searching for a specific file.
800  *
801  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
802  *
803  * This function returns 1 if the caller should continue to search,
804  * or 0 if it should not.  If there is an error reading one of the
805  * index blocks, it will a negative error code.
806  *
807  * If start_hash is non-null, it will be filled in with the starting
808  * hash of the next page.
809  */
810 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
811                                  struct dx_frame *frame,
812                                  struct dx_frame *frames,
813                                  __u32 *start_hash)
814 {
815         struct dx_frame *p;
816         struct buffer_head *bh;
817         int num_frames = 0;
818         __u32 bhash;
819
820         p = frame;
821         /*
822          * Find the next leaf page by incrementing the frame pointer.
823          * If we run out of entries in the interior node, loop around and
824          * increment pointer in the parent node.  When we break out of
825          * this loop, num_frames indicates the number of interior
826          * nodes need to be read.
827          */
828         while (1) {
829                 if (++(p->at) < p->entries + dx_get_count(p->entries))
830                         break;
831                 if (p == frames)
832                         return 0;
833                 num_frames++;
834                 p--;
835         }
836
837         /*
838          * If the hash is 1, then continue only if the next page has a
839          * continuation hash of any value.  This is used for readdir
840          * handling.  Otherwise, check to see if the hash matches the
841          * desired contiuation hash.  If it doesn't, return since
842          * there's no point to read in the successive index pages.
843          */
844         bhash = dx_get_hash(p->at);
845         if (start_hash)
846                 *start_hash = bhash;
847         if ((hash & 1) == 0) {
848                 if ((bhash & ~1) != hash)
849                         return 0;
850         }
851         /*
852          * If the hash is HASH_NB_ALWAYS, we always go to the next
853          * block so no check is necessary
854          */
855         while (num_frames--) {
856                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
857                 if (IS_ERR(bh))
858                         return PTR_ERR(bh);
859                 p++;
860                 brelse(p->bh);
861                 p->bh = bh;
862                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
863         }
864         return 1;
865 }
866
867
868 /*
869  * This function fills a red-black tree with information from a
870  * directory block.  It returns the number directory entries loaded
871  * into the tree.  If there is an error it is returned in err.
872  */
873 static int htree_dirblock_to_tree(struct file *dir_file,
874                                   struct inode *dir, ext4_lblk_t block,
875                                   struct dx_hash_info *hinfo,
876                                   __u32 start_hash, __u32 start_minor_hash)
877 {
878         struct buffer_head *bh;
879         struct ext4_dir_entry_2 *de, *top;
880         int err = 0, count = 0;
881
882         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
883                                                         (unsigned long)block));
884         bh = ext4_read_dirblock(dir, block, DIRENT);
885         if (IS_ERR(bh))
886                 return PTR_ERR(bh);
887
888         de = (struct ext4_dir_entry_2 *) bh->b_data;
889         top = (struct ext4_dir_entry_2 *) ((char *) de +
890                                            dir->i_sb->s_blocksize -
891                                            EXT4_DIR_REC_LEN(0));
892         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
893                 if (ext4_check_dir_entry(dir, NULL, de, bh,
894                                 bh->b_data, bh->b_size,
895                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
896                                          + ((char *)de - bh->b_data))) {
897                         /* silently ignore the rest of the block */
898                         break;
899                 }
900                 ext4fs_dirhash(de->name, de->name_len, hinfo);
901                 if ((hinfo->hash < start_hash) ||
902                     ((hinfo->hash == start_hash) &&
903                      (hinfo->minor_hash < start_minor_hash)))
904                         continue;
905                 if (de->inode == 0)
906                         continue;
907                 if ((err = ext4_htree_store_dirent(dir_file,
908                                    hinfo->hash, hinfo->minor_hash, de)) != 0) {
909                         brelse(bh);
910                         return err;
911                 }
912                 count++;
913         }
914         brelse(bh);
915         return count;
916 }
917
918
919 /*
920  * This function fills a red-black tree with information from a
921  * directory.  We start scanning the directory in hash order, starting
922  * at start_hash and start_minor_hash.
923  *
924  * This function returns the number of entries inserted into the tree,
925  * or a negative error code.
926  */
927 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
928                          __u32 start_minor_hash, __u32 *next_hash)
929 {
930         struct dx_hash_info hinfo;
931         struct ext4_dir_entry_2 *de;
932         struct dx_frame frames[2], *frame;
933         struct inode *dir;
934         ext4_lblk_t block;
935         int count = 0;
936         int ret, err;
937         __u32 hashval;
938
939         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
940                        start_hash, start_minor_hash));
941         dir = file_inode(dir_file);
942         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
943                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
944                 if (hinfo.hash_version <= DX_HASH_TEA)
945                         hinfo.hash_version +=
946                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
947                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
948                 if (ext4_has_inline_data(dir)) {
949                         int has_inline_data = 1;
950                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
951                                                         &hinfo, start_hash,
952                                                         start_minor_hash,
953                                                         &has_inline_data);
954                         if (has_inline_data) {
955                                 *next_hash = ~0;
956                                 return count;
957                         }
958                 }
959                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
960                                                start_hash, start_minor_hash);
961                 *next_hash = ~0;
962                 return count;
963         }
964         hinfo.hash = start_hash;
965         hinfo.minor_hash = 0;
966         frame = dx_probe(NULL, dir, &hinfo, frames);
967         if (IS_ERR(frame))
968                 return PTR_ERR(frame);
969
970         /* Add '.' and '..' from the htree header */
971         if (!start_hash && !start_minor_hash) {
972                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
973                 if ((err = ext4_htree_store_dirent(dir_file, 0, 0, de)) != 0)
974                         goto errout;
975                 count++;
976         }
977         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
978                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
979                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
980                 if ((err = ext4_htree_store_dirent(dir_file, 2, 0, de)) != 0)
981                         goto errout;
982                 count++;
983         }
984
985         while (1) {
986                 block = dx_get_block(frame->at);
987                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
988                                              start_hash, start_minor_hash);
989                 if (ret < 0) {
990                         err = ret;
991                         goto errout;
992                 }
993                 count += ret;
994                 hashval = ~0;
995                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
996                                             frame, frames, &hashval);
997                 *next_hash = hashval;
998                 if (ret < 0) {
999                         err = ret;
1000                         goto errout;
1001                 }
1002                 /*
1003                  * Stop if:  (a) there are no more entries, or
1004                  * (b) we have inserted at least one entry and the
1005                  * next hash value is not a continuation
1006                  */
1007                 if ((ret == 0) ||
1008                     (count && ((hashval & 1) == 0)))
1009                         break;
1010         }
1011         dx_release(frames);
1012         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1013                        "next hash: %x\n", count, *next_hash));
1014         return count;
1015 errout:
1016         dx_release(frames);
1017         return (err);
1018 }
1019
1020 static inline int search_dirblock(struct buffer_head *bh,
1021                                   struct inode *dir,
1022                                   const struct qstr *d_name,
1023                                   unsigned int offset,
1024                                   struct ext4_dir_entry_2 **res_dir)
1025 {
1026         return search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1027                           d_name, offset, res_dir);
1028 }
1029
1030 /*
1031  * Directory block splitting, compacting
1032  */
1033
1034 /*
1035  * Create map of hash values, offsets, and sizes, stored at end of block.
1036  * Returns number of entries mapped.
1037  */
1038 static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
1039                        struct dx_hash_info *hinfo,
1040                        struct dx_map_entry *map_tail)
1041 {
1042         int count = 0;
1043         char *base = (char *) de;
1044         struct dx_hash_info h = *hinfo;
1045
1046         while ((char *) de < base + blocksize) {
1047                 if (de->name_len && de->inode) {
1048                         ext4fs_dirhash(de->name, de->name_len, &h);
1049                         map_tail--;
1050                         map_tail->hash = h.hash;
1051                         map_tail->offs = ((char *) de - base)>>2;
1052                         map_tail->size = le16_to_cpu(de->rec_len);
1053                         count++;
1054                         cond_resched();
1055                 }
1056                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1057                 de = ext4_next_entry(de, blocksize);
1058         }
1059         return count;
1060 }
1061
1062 /* Sort map by hash value */
1063 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1064 {
1065         struct dx_map_entry *p, *q, *top = map + count - 1;
1066         int more;
1067         /* Combsort until bubble sort doesn't suck */
1068         while (count > 2) {
1069                 count = count*10/13;
1070                 if (count - 9 < 2) /* 9, 10 -> 11 */
1071                         count = 11;
1072                 for (p = top, q = p - count; q >= map; p--, q--)
1073                         if (p->hash < q->hash)
1074                                 swap(*p, *q);
1075         }
1076         /* Garden variety bubble sort */
1077         do {
1078                 more = 0;
1079                 q = top;
1080                 while (q-- > map) {
1081                         if (q[1].hash >= q[0].hash)
1082                                 continue;
1083                         swap(*(q+1), *q);
1084                         more = 1;
1085                 }
1086         } while(more);
1087 }
1088
1089 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1090 {
1091         struct dx_entry *entries = frame->entries;
1092         struct dx_entry *old = frame->at, *new = old + 1;
1093         int count = dx_get_count(entries);
1094
1095         assert(count < dx_get_limit(entries));
1096         assert(old < entries + count);
1097         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1098         dx_set_hash(new, hash);
1099         dx_set_block(new, block);
1100         dx_set_count(entries, count + 1);
1101 }
1102
1103 /*
1104  * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.
1105  *
1106  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
1107  * `de != NULL' is guaranteed by caller.
1108  */
1109 static inline int ext4_match (int len, const char * const name,
1110                               struct ext4_dir_entry_2 * de)
1111 {
1112         if (len != de->name_len)
1113                 return 0;
1114         if (!de->inode)
1115                 return 0;
1116         return !memcmp(name, de->name, len);
1117 }
1118
1119 /*
1120  * Returns 0 if not found, -1 on failure, and 1 on success
1121  */
1122 int search_dir(struct buffer_head *bh,
1123                char *search_buf,
1124                int buf_size,
1125                struct inode *dir,
1126                const struct qstr *d_name,
1127                unsigned int offset,
1128                struct ext4_dir_entry_2 **res_dir)
1129 {
1130         struct ext4_dir_entry_2 * de;
1131         char * dlimit;
1132         int de_len;
1133         const char *name = d_name->name;
1134         int namelen = d_name->len;
1135
1136         de = (struct ext4_dir_entry_2 *)search_buf;
1137         dlimit = search_buf + buf_size;
1138         while ((char *) de < dlimit) {
1139                 /* this code is executed quadratically often */
1140                 /* do minimal checking `by hand' */
1141
1142                 if ((char *) de + namelen <= dlimit &&
1143                     ext4_match (namelen, name, de)) {
1144                         /* found a match - just to be sure, do a full check */
1145                         if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
1146                                                  bh->b_size, offset))
1147                                 return -1;
1148                         *res_dir = de;
1149                         return 1;
1150                 }
1151                 /* prevent looping on a bad block */
1152                 de_len = ext4_rec_len_from_disk(de->rec_len,
1153                                                 dir->i_sb->s_blocksize);
1154                 if (de_len <= 0)
1155                         return -1;
1156                 offset += de_len;
1157                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1158         }
1159         return 0;
1160 }
1161
1162 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1163                                struct ext4_dir_entry *de)
1164 {
1165         struct super_block *sb = dir->i_sb;
1166
1167         if (!is_dx(dir))
1168                 return 0;
1169         if (block == 0)
1170                 return 1;
1171         if (de->inode == 0 &&
1172             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1173                         sb->s_blocksize)
1174                 return 1;
1175         return 0;
1176 }
1177
1178 /*
1179  *      ext4_find_entry()
1180  *
1181  * finds an entry in the specified directory with the wanted name. It
1182  * returns the cache buffer in which the entry was found, and the entry
1183  * itself (as a parameter - res_dir). It does NOT read the inode of the
1184  * entry - you'll have to do that yourself if you want to.
1185  *
1186  * The returned buffer_head has ->b_count elevated.  The caller is expected
1187  * to brelse() it when appropriate.
1188  */
1189 static struct buffer_head * ext4_find_entry (struct inode *dir,
1190                                         const struct qstr *d_name,
1191                                         struct ext4_dir_entry_2 **res_dir,
1192                                         int *inlined)
1193 {
1194         struct super_block *sb;
1195         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1196         struct buffer_head *bh, *ret = NULL;
1197         ext4_lblk_t start, block, b;
1198         const u8 *name = d_name->name;
1199         int ra_max = 0;         /* Number of bh's in the readahead
1200                                    buffer, bh_use[] */
1201         int ra_ptr = 0;         /* Current index into readahead
1202                                    buffer */
1203         int num = 0;
1204         ext4_lblk_t  nblocks;
1205         int i, namelen;
1206
1207         *res_dir = NULL;
1208         sb = dir->i_sb;
1209         namelen = d_name->len;
1210         if (namelen > EXT4_NAME_LEN)
1211                 return NULL;
1212
1213         if (ext4_has_inline_data(dir)) {
1214                 int has_inline_data = 1;
1215                 ret = ext4_find_inline_entry(dir, d_name, res_dir,
1216                                              &has_inline_data);
1217                 if (has_inline_data) {
1218                         if (inlined)
1219                                 *inlined = 1;
1220                         return ret;
1221                 }
1222         }
1223
1224         if ((namelen <= 2) && (name[0] == '.') &&
1225             (name[1] == '.' || name[1] == '\0')) {
1226                 /*
1227                  * "." or ".." will only be in the first block
1228                  * NFS may look up ".."; "." should be handled by the VFS
1229                  */
1230                 block = start = 0;
1231                 nblocks = 1;
1232                 goto restart;
1233         }
1234         if (is_dx(dir)) {
1235                 bh = ext4_dx_find_entry(dir, d_name, res_dir);
1236                 /*
1237                  * On success, or if the error was file not found,
1238                  * return.  Otherwise, fall back to doing a search the
1239                  * old fashioned way.
1240                  */
1241                 if (!IS_ERR(bh) || PTR_ERR(bh) != ERR_BAD_DX_DIR)
1242                         return bh;
1243                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1244                                "falling back\n"));
1245         }
1246         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1247         start = EXT4_I(dir)->i_dir_start_lookup;
1248         if (start >= nblocks)
1249                 start = 0;
1250         block = start;
1251 restart:
1252         do {
1253                 /*
1254                  * We deal with the read-ahead logic here.
1255                  */
1256                 if (ra_ptr >= ra_max) {
1257                         /* Refill the readahead buffer */
1258                         ra_ptr = 0;
1259                         b = block;
1260                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
1261                                 /*
1262                                  * Terminate if we reach the end of the
1263                                  * directory and must wrap, or if our
1264                                  * search has finished at this block.
1265                                  */
1266                                 if (b >= nblocks || (num && block == start)) {
1267                                         bh_use[ra_max] = NULL;
1268                                         break;
1269                                 }
1270                                 num++;
1271                                 bh = ext4_getblk(NULL, dir, b++, 0);
1272                                 if (unlikely(IS_ERR(bh))) {
1273                                         if (ra_max == 0)
1274                                                 return bh;
1275                                         break;
1276                                 }
1277                                 bh_use[ra_max] = bh;
1278                                 if (bh)
1279                                         ll_rw_block(READ | REQ_META | REQ_PRIO,
1280                                                     1, &bh);
1281                         }
1282                 }
1283                 if ((bh = bh_use[ra_ptr++]) == NULL)
1284                         goto next;
1285                 wait_on_buffer(bh);
1286                 if (!buffer_uptodate(bh)) {
1287                         /* read error, skip block & hope for the best */
1288                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1289                                          (unsigned long) block);
1290                         brelse(bh);
1291                         goto next;
1292                 }
1293                 if (!buffer_verified(bh) &&
1294                     !is_dx_internal_node(dir, block,
1295                                          (struct ext4_dir_entry *)bh->b_data) &&
1296                     !ext4_dirent_csum_verify(dir,
1297                                 (struct ext4_dir_entry *)bh->b_data)) {
1298                         EXT4_ERROR_INODE(dir, "checksumming directory "
1299                                          "block %lu", (unsigned long)block);
1300                         brelse(bh);
1301                         goto next;
1302                 }
1303                 set_buffer_verified(bh);
1304                 i = search_dirblock(bh, dir, d_name,
1305                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1306                 if (i == 1) {
1307                         EXT4_I(dir)->i_dir_start_lookup = block;
1308                         ret = bh;
1309                         goto cleanup_and_exit;
1310                 } else {
1311                         brelse(bh);
1312                         if (i < 0)
1313                                 goto cleanup_and_exit;
1314                 }
1315         next:
1316                 if (++block >= nblocks)
1317                         block = 0;
1318         } while (block != start);
1319
1320         /*
1321          * If the directory has grown while we were searching, then
1322          * search the last part of the directory before giving up.
1323          */
1324         block = nblocks;
1325         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1326         if (block < nblocks) {
1327                 start = 0;
1328                 goto restart;
1329         }
1330
1331 cleanup_and_exit:
1332         /* Clean up the read-ahead blocks */
1333         for (; ra_ptr < ra_max; ra_ptr++)
1334                 brelse(bh_use[ra_ptr]);
1335         return ret;
1336 }
1337
1338 static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct qstr *d_name,
1339                        struct ext4_dir_entry_2 **res_dir)
1340 {
1341         struct super_block * sb = dir->i_sb;
1342         struct dx_hash_info     hinfo;
1343         struct dx_frame frames[2], *frame;
1344         struct buffer_head *bh;
1345         ext4_lblk_t block;
1346         int retval;
1347
1348         frame = dx_probe(d_name, dir, &hinfo, frames);
1349         if (IS_ERR(frame))
1350                 return (struct buffer_head *) frame;
1351         do {
1352                 block = dx_get_block(frame->at);
1353                 bh = ext4_read_dirblock(dir, block, DIRENT);
1354                 if (IS_ERR(bh))
1355                         goto errout;
1356
1357                 retval = search_dirblock(bh, dir, d_name,
1358                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1359                                          res_dir);
1360                 if (retval == 1)
1361                         goto success;
1362                 brelse(bh);
1363                 if (retval == -1) {
1364                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1365                         goto errout;
1366                 }
1367
1368                 /* Check to see if we should continue to search */
1369                 retval = ext4_htree_next_block(dir, hinfo.hash, frame,
1370                                                frames, NULL);
1371                 if (retval < 0) {
1372                         ext4_warning(sb,
1373                              "error %d reading index page in directory #%lu",
1374                              retval, dir->i_ino);
1375                         bh = ERR_PTR(retval);
1376                         goto errout;
1377                 }
1378         } while (retval == 1);
1379
1380         bh = NULL;
1381 errout:
1382         dxtrace(printk(KERN_DEBUG "%s not found\n", d_name->name));
1383 success:
1384         dx_release(frames);
1385         return bh;
1386 }
1387
1388 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1389 {
1390         struct inode *inode;
1391         struct ext4_dir_entry_2 *de;
1392         struct buffer_head *bh;
1393
1394         if (dentry->d_name.len > EXT4_NAME_LEN)
1395                 return ERR_PTR(-ENAMETOOLONG);
1396
1397         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1398         if (IS_ERR(bh))
1399                 return (struct dentry *) bh;
1400         inode = NULL;
1401         if (bh) {
1402                 __u32 ino = le32_to_cpu(de->inode);
1403                 brelse(bh);
1404                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1405                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1406                         return ERR_PTR(-EIO);
1407                 }
1408                 if (unlikely(ino == dir->i_ino)) {
1409                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1410                                          dentry);
1411                         return ERR_PTR(-EIO);
1412                 }
1413                 inode = ext4_iget_normal(dir->i_sb, ino);
1414                 if (inode == ERR_PTR(-ESTALE)) {
1415                         EXT4_ERROR_INODE(dir,
1416                                          "deleted inode referenced: %u",
1417                                          ino);
1418                         return ERR_PTR(-EIO);
1419                 }
1420         }
1421         return d_splice_alias(inode, dentry);
1422 }
1423
1424
1425 struct dentry *ext4_get_parent(struct dentry *child)
1426 {
1427         __u32 ino;
1428         static const struct qstr dotdot = QSTR_INIT("..", 2);
1429         struct ext4_dir_entry_2 * de;
1430         struct buffer_head *bh;
1431
1432         bh = ext4_find_entry(child->d_inode, &dotdot, &de, NULL);
1433         if (IS_ERR(bh))
1434                 return (struct dentry *) bh;
1435         if (!bh)
1436                 return ERR_PTR(-ENOENT);
1437         ino = le32_to_cpu(de->inode);
1438         brelse(bh);
1439
1440         if (!ext4_valid_inum(child->d_inode->i_sb, ino)) {
1441                 EXT4_ERROR_INODE(child->d_inode,
1442                                  "bad parent inode number: %u", ino);
1443                 return ERR_PTR(-EIO);
1444         }
1445
1446         return d_obtain_alias(ext4_iget_normal(child->d_inode->i_sb, ino));
1447 }
1448
1449 /*
1450  * Move count entries from end of map between two memory locations.
1451  * Returns pointer to last entry moved.
1452  */
1453 static struct ext4_dir_entry_2 *
1454 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1455                 unsigned blocksize)
1456 {
1457         unsigned rec_len = 0;
1458
1459         while (count--) {
1460                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1461                                                 (from + (map->offs<<2));
1462                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1463                 memcpy (to, de, rec_len);
1464                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1465                                 ext4_rec_len_to_disk(rec_len, blocksize);
1466                 de->inode = 0;
1467                 map++;
1468                 to += rec_len;
1469         }
1470         return (struct ext4_dir_entry_2 *) (to - rec_len);
1471 }
1472
1473 /*
1474  * Compact each dir entry in the range to the minimal rec_len.
1475  * Returns pointer to last entry in range.
1476  */
1477 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1478 {
1479         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1480         unsigned rec_len = 0;
1481
1482         prev = to = de;
1483         while ((char*)de < base + blocksize) {
1484                 next = ext4_next_entry(de, blocksize);
1485                 if (de->inode && de->name_len) {
1486                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1487                         if (de > to)
1488                                 memmove(to, de, rec_len);
1489                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1490                         prev = to;
1491                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1492                 }
1493                 de = next;
1494         }
1495         return prev;
1496 }
1497
1498 /*
1499  * Split a full leaf block to make room for a new dir entry.
1500  * Allocate a new block, and move entries so that they are approx. equally full.
1501  * Returns pointer to de in block into which the new entry will be inserted.
1502  */
1503 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1504                         struct buffer_head **bh,struct dx_frame *frame,
1505                         struct dx_hash_info *hinfo)
1506 {
1507         unsigned blocksize = dir->i_sb->s_blocksize;
1508         unsigned count, continued;
1509         struct buffer_head *bh2;
1510         ext4_lblk_t newblock;
1511         u32 hash2;
1512         struct dx_map_entry *map;
1513         char *data1 = (*bh)->b_data, *data2;
1514         unsigned split, move, size;
1515         struct ext4_dir_entry_2 *de = NULL, *de2;
1516         struct ext4_dir_entry_tail *t;
1517         int     csum_size = 0;
1518         int     err = 0, i;
1519
1520         if (ext4_has_metadata_csum(dir->i_sb))
1521                 csum_size = sizeof(struct ext4_dir_entry_tail);
1522
1523         bh2 = ext4_append(handle, dir, &newblock);
1524         if (IS_ERR(bh2)) {
1525                 brelse(*bh);
1526                 *bh = NULL;
1527                 return (struct ext4_dir_entry_2 *) bh2;
1528         }
1529
1530         BUFFER_TRACE(*bh, "get_write_access");
1531         err = ext4_journal_get_write_access(handle, *bh);
1532         if (err)
1533                 goto journal_error;
1534
1535         BUFFER_TRACE(frame->bh, "get_write_access");
1536         err = ext4_journal_get_write_access(handle, frame->bh);
1537         if (err)
1538                 goto journal_error;
1539
1540         data2 = bh2->b_data;
1541
1542         /* create map in the end of data2 block */
1543         map = (struct dx_map_entry *) (data2 + blocksize);
1544         count = dx_make_map((struct ext4_dir_entry_2 *) data1,
1545                              blocksize, hinfo, map);
1546         map -= count;
1547         dx_sort_map(map, count);
1548         /* Split the existing block in the middle, size-wise */
1549         size = 0;
1550         move = 0;
1551         for (i = count-1; i >= 0; i--) {
1552                 /* is more than half of this entry in 2nd half of the block? */
1553                 if (size + map[i].size/2 > blocksize/2)
1554                         break;
1555                 size += map[i].size;
1556                 move++;
1557         }
1558         /* map index at which we will split */
1559         split = count - move;
1560         hash2 = map[split].hash;
1561         continued = hash2 == map[split - 1].hash;
1562         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1563                         (unsigned long)dx_get_block(frame->at),
1564                                         hash2, split, count-split));
1565
1566         /* Fancy dance to stay within two buffers */
1567         de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
1568         de = dx_pack_dirents(data1, blocksize);
1569         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1570                                            (char *) de,
1571                                            blocksize);
1572         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1573                                             (char *) de2,
1574                                             blocksize);
1575         if (csum_size) {
1576                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1577                 initialize_dirent_tail(t, blocksize);
1578
1579                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1580                 initialize_dirent_tail(t, blocksize);
1581         }
1582
1583         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
1584         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
1585
1586         /* Which block gets the new entry? */
1587         if (hinfo->hash >= hash2) {
1588                 swap(*bh, bh2);
1589                 de = de2;
1590         }
1591         dx_insert_block(frame, hash2 + continued, newblock);
1592         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1593         if (err)
1594                 goto journal_error;
1595         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1596         if (err)
1597                 goto journal_error;
1598         brelse(bh2);
1599         dxtrace(dx_show_index("frame", frame->entries));
1600         return de;
1601
1602 journal_error:
1603         brelse(*bh);
1604         brelse(bh2);
1605         *bh = NULL;
1606         ext4_std_error(dir->i_sb, err);
1607         return ERR_PTR(err);
1608 }
1609
1610 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1611                       struct buffer_head *bh,
1612                       void *buf, int buf_size,
1613                       const char *name, int namelen,
1614                       struct ext4_dir_entry_2 **dest_de)
1615 {
1616         struct ext4_dir_entry_2 *de;
1617         unsigned short reclen = EXT4_DIR_REC_LEN(namelen);
1618         int nlen, rlen;
1619         unsigned int offset = 0;
1620         char *top;
1621
1622         de = (struct ext4_dir_entry_2 *)buf;
1623         top = buf + buf_size - reclen;
1624         while ((char *) de <= top) {
1625                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1626                                          buf, buf_size, offset))
1627                         return -EIO;
1628                 if (ext4_match(namelen, name, de))
1629                         return -EEXIST;
1630                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1631                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1632                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1633                         break;
1634                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1635                 offset += rlen;
1636         }
1637         if ((char *) de > top)
1638                 return -ENOSPC;
1639
1640         *dest_de = de;
1641         return 0;
1642 }
1643
1644 void ext4_insert_dentry(struct inode *inode,
1645                         struct ext4_dir_entry_2 *de,
1646                         int buf_size,
1647                         const char *name, int namelen)
1648 {
1649
1650         int nlen, rlen;
1651
1652         nlen = EXT4_DIR_REC_LEN(de->name_len);
1653         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1654         if (de->inode) {
1655                 struct ext4_dir_entry_2 *de1 =
1656                                 (struct ext4_dir_entry_2 *)((char *)de + nlen);
1657                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1658                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1659                 de = de1;
1660         }
1661         de->file_type = EXT4_FT_UNKNOWN;
1662         de->inode = cpu_to_le32(inode->i_ino);
1663         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1664         de->name_len = namelen;
1665         memcpy(de->name, name, namelen);
1666 }
1667 /*
1668  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1669  * it points to a directory entry which is guaranteed to be large
1670  * enough for new directory entry.  If de is NULL, then
1671  * add_dirent_to_buf will attempt search the directory block for
1672  * space.  It will return -ENOSPC if no space is available, and -EIO
1673  * and -EEXIST if directory entry already exists.
1674  */
1675 static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
1676                              struct inode *inode, struct ext4_dir_entry_2 *de,
1677                              struct buffer_head *bh)
1678 {
1679         struct inode    *dir = dentry->d_parent->d_inode;
1680         const char      *name = dentry->d_name.name;
1681         int             namelen = dentry->d_name.len;
1682         unsigned int    blocksize = dir->i_sb->s_blocksize;
1683         int             csum_size = 0;
1684         int             err;
1685
1686         if (ext4_has_metadata_csum(inode->i_sb))
1687                 csum_size = sizeof(struct ext4_dir_entry_tail);
1688
1689         if (!de) {
1690                 err = ext4_find_dest_de(dir, inode,
1691                                         bh, bh->b_data, blocksize - csum_size,
1692                                         name, namelen, &de);
1693                 if (err)
1694                         return err;
1695         }
1696         BUFFER_TRACE(bh, "get_write_access");
1697         err = ext4_journal_get_write_access(handle, bh);
1698         if (err) {
1699                 ext4_std_error(dir->i_sb, err);
1700                 return err;
1701         }
1702
1703         /* By now the buffer is marked for journaling */
1704         ext4_insert_dentry(inode, de, blocksize, name, namelen);
1705
1706         /*
1707          * XXX shouldn't update any times until successful
1708          * completion of syscall, but too many callers depend
1709          * on this.
1710          *
1711          * XXX similarly, too many callers depend on
1712          * ext4_new_inode() setting the times, but error
1713          * recovery deletes the inode, so the worst that can
1714          * happen is that the times are slightly out of date
1715          * and/or different from the directory change time.
1716          */
1717         dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
1718         ext4_update_dx_flag(dir);
1719         dir->i_version++;
1720         ext4_mark_inode_dirty(handle, dir);
1721         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1722         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1723         if (err)
1724                 ext4_std_error(dir->i_sb, err);
1725         return 0;
1726 }
1727
1728 /*
1729  * This converts a one block unindexed directory to a 3 block indexed
1730  * directory, and adds the dentry to the indexed directory.
1731  */
1732 static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1733                             struct inode *inode, struct buffer_head *bh)
1734 {
1735         struct inode    *dir = dentry->d_parent->d_inode;
1736         const char      *name = dentry->d_name.name;
1737         int             namelen = dentry->d_name.len;
1738         struct buffer_head *bh2;
1739         struct dx_root  *root;
1740         struct dx_frame frames[2], *frame;
1741         struct dx_entry *entries;
1742         struct ext4_dir_entry_2 *de, *de2;
1743         struct ext4_dir_entry_tail *t;
1744         char            *data1, *top;
1745         unsigned        len;
1746         int             retval;
1747         unsigned        blocksize;
1748         struct dx_hash_info hinfo;
1749         ext4_lblk_t  block;
1750         struct fake_dirent *fde;
1751         int             csum_size = 0;
1752
1753         if (ext4_has_metadata_csum(inode->i_sb))
1754                 csum_size = sizeof(struct ext4_dir_entry_tail);
1755
1756         blocksize =  dir->i_sb->s_blocksize;
1757         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1758         BUFFER_TRACE(bh, "get_write_access");
1759         retval = ext4_journal_get_write_access(handle, bh);
1760         if (retval) {
1761                 ext4_std_error(dir->i_sb, retval);
1762                 brelse(bh);
1763                 return retval;
1764         }
1765         root = (struct dx_root *) bh->b_data;
1766
1767         /* The 0th block becomes the root, move the dirents out */
1768         fde = &root->dotdot;
1769         de = (struct ext4_dir_entry_2 *)((char *)fde +
1770                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1771         if ((char *) de >= (((char *) root) + blocksize)) {
1772                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1773                 brelse(bh);
1774                 return -EIO;
1775         }
1776         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1777
1778         /* Allocate new block for the 0th block's dirents */
1779         bh2 = ext4_append(handle, dir, &block);
1780         if (IS_ERR(bh2)) {
1781                 brelse(bh);
1782                 return PTR_ERR(bh2);
1783         }
1784         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1785         data1 = bh2->b_data;
1786
1787         memcpy (data1, de, len);
1788         de = (struct ext4_dir_entry_2 *) data1;
1789         top = data1 + len;
1790         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1791                 de = de2;
1792         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1793                                            (char *) de,
1794                                            blocksize);
1795
1796         if (csum_size) {
1797                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1798                 initialize_dirent_tail(t, blocksize);
1799         }
1800
1801         /* Initialize the root; the dot dirents already exist */
1802         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1803         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
1804                                            blocksize);
1805         memset (&root->info, 0, sizeof(root->info));
1806         root->info.info_length = sizeof(root->info);
1807         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1808         entries = root->entries;
1809         dx_set_block(entries, 1);
1810         dx_set_count(entries, 1);
1811         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
1812
1813         /* Initialize as for dx_probe */
1814         hinfo.hash_version = root->info.hash_version;
1815         if (hinfo.hash_version <= DX_HASH_TEA)
1816                 hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
1817         hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1818         ext4fs_dirhash(name, namelen, &hinfo);
1819         frame = frames;
1820         frame->entries = entries;
1821         frame->at = entries;
1822         frame->bh = bh;
1823         bh = bh2;
1824
1825         ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1826         ext4_handle_dirty_dirent_node(handle, dir, bh);
1827
1828         de = do_split(handle,dir, &bh, frame, &hinfo);
1829         if (IS_ERR(de)) {
1830                 /*
1831                  * Even if the block split failed, we have to properly write
1832                  * out all the changes we did so far. Otherwise we can end up
1833                  * with corrupted filesystem.
1834                  */
1835                 ext4_mark_inode_dirty(handle, dir);
1836                 dx_release(frames);
1837                 return PTR_ERR(de);
1838         }
1839         dx_release(frames);
1840
1841         retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
1842         brelse(bh);
1843         return retval;
1844 }
1845
1846 /*
1847  *      ext4_add_entry()
1848  *
1849  * adds a file entry to the specified directory, using the same
1850  * semantics as ext4_find_entry(). It returns NULL if it failed.
1851  *
1852  * NOTE!! The inode part of 'de' is left at 0 - which means you
1853  * may not sleep between calling this and putting something into
1854  * the entry, as someone else might have used it while you slept.
1855  */
1856 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
1857                           struct inode *inode)
1858 {
1859         struct inode *dir = dentry->d_parent->d_inode;
1860         struct buffer_head *bh;
1861         struct ext4_dir_entry_2 *de;
1862         struct ext4_dir_entry_tail *t;
1863         struct super_block *sb;
1864         int     retval;
1865         int     dx_fallback=0;
1866         unsigned blocksize;
1867         ext4_lblk_t block, blocks;
1868         int     csum_size = 0;
1869
1870         if (ext4_has_metadata_csum(inode->i_sb))
1871                 csum_size = sizeof(struct ext4_dir_entry_tail);
1872
1873         sb = dir->i_sb;
1874         blocksize = sb->s_blocksize;
1875         if (!dentry->d_name.len)
1876                 return -EINVAL;
1877
1878         if (ext4_has_inline_data(dir)) {
1879                 retval = ext4_try_add_inline_entry(handle, dentry, inode);
1880                 if (retval < 0)
1881                         return retval;
1882                 if (retval == 1) {
1883                         retval = 0;
1884                         return retval;
1885                 }
1886         }
1887
1888         if (is_dx(dir)) {
1889                 retval = ext4_dx_add_entry(handle, dentry, inode);
1890                 if (!retval || (retval != ERR_BAD_DX_DIR))
1891                         return retval;
1892                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
1893                 dx_fallback++;
1894                 ext4_mark_inode_dirty(handle, dir);
1895         }
1896         blocks = dir->i_size >> sb->s_blocksize_bits;
1897         for (block = 0; block < blocks; block++) {
1898                 bh = ext4_read_dirblock(dir, block, DIRENT);
1899                 if (IS_ERR(bh))
1900                         return PTR_ERR(bh);
1901
1902                 retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1903                 if (retval != -ENOSPC) {
1904                         brelse(bh);
1905                         return retval;
1906                 }
1907
1908                 if (blocks == 1 && !dx_fallback &&
1909                     EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX))
1910                         return make_indexed_dir(handle, dentry, inode, bh);
1911                 brelse(bh);
1912         }
1913         bh = ext4_append(handle, dir, &block);
1914         if (IS_ERR(bh))
1915                 return PTR_ERR(bh);
1916         de = (struct ext4_dir_entry_2 *) bh->b_data;
1917         de->inode = 0;
1918         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
1919
1920         if (csum_size) {
1921                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
1922                 initialize_dirent_tail(t, blocksize);
1923         }
1924
1925         retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
1926         brelse(bh);
1927         if (retval == 0)
1928                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
1929         return retval;
1930 }
1931
1932 /*
1933  * Returns 0 for success, or a negative error value
1934  */
1935 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
1936                              struct inode *inode)
1937 {
1938         struct dx_frame frames[2], *frame;
1939         struct dx_entry *entries, *at;
1940         struct dx_hash_info hinfo;
1941         struct buffer_head *bh;
1942         struct inode *dir = dentry->d_parent->d_inode;
1943         struct super_block *sb = dir->i_sb;
1944         struct ext4_dir_entry_2 *de;
1945         int err;
1946
1947         frame = dx_probe(&dentry->d_name, dir, &hinfo, frames);
1948         if (IS_ERR(frame))
1949                 return PTR_ERR(frame);
1950         entries = frame->entries;
1951         at = frame->at;
1952         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
1953         if (IS_ERR(bh)) {
1954                 err = PTR_ERR(bh);
1955                 bh = NULL;
1956                 goto cleanup;
1957         }
1958
1959         BUFFER_TRACE(bh, "get_write_access");
1960         err = ext4_journal_get_write_access(handle, bh);
1961         if (err)
1962                 goto journal_error;
1963
1964         err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1965         if (err != -ENOSPC)
1966                 goto cleanup;
1967
1968         /* Block full, should compress but for now just split */
1969         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
1970                        dx_get_count(entries), dx_get_limit(entries)));
1971         /* Need to split index? */
1972         if (dx_get_count(entries) == dx_get_limit(entries)) {
1973                 ext4_lblk_t newblock;
1974                 unsigned icount = dx_get_count(entries);
1975                 int levels = frame - frames;
1976                 struct dx_entry *entries2;
1977                 struct dx_node *node2;
1978                 struct buffer_head *bh2;
1979
1980                 if (levels && (dx_get_count(frames->entries) ==
1981                                dx_get_limit(frames->entries))) {
1982                         ext4_warning(sb, "Directory index full!");
1983                         err = -ENOSPC;
1984                         goto cleanup;
1985                 }
1986                 bh2 = ext4_append(handle, dir, &newblock);
1987                 if (IS_ERR(bh2)) {
1988                         err = PTR_ERR(bh2);
1989                         goto cleanup;
1990                 }
1991                 node2 = (struct dx_node *)(bh2->b_data);
1992                 entries2 = node2->entries;
1993                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
1994                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
1995                                                            sb->s_blocksize);
1996                 BUFFER_TRACE(frame->bh, "get_write_access");
1997                 err = ext4_journal_get_write_access(handle, frame->bh);
1998                 if (err)
1999                         goto journal_error;
2000                 if (levels) {
2001                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2002                         unsigned hash2 = dx_get_hash(entries + icount1);
2003                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2004                                        icount1, icount2));
2005
2006                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2007                         err = ext4_journal_get_write_access(handle,
2008                                                              frames[0].bh);
2009                         if (err)
2010                                 goto journal_error;
2011
2012                         memcpy((char *) entries2, (char *) (entries + icount1),
2013                                icount2 * sizeof(struct dx_entry));
2014                         dx_set_count(entries, icount1);
2015                         dx_set_count(entries2, icount2);
2016                         dx_set_limit(entries2, dx_node_limit(dir));
2017
2018                         /* Which index block gets the new entry? */
2019                         if (at - entries >= icount1) {
2020                                 frame->at = at = at - entries - icount1 + entries2;
2021                                 frame->entries = entries = entries2;
2022                                 swap(frame->bh, bh2);
2023                         }
2024                         dx_insert_block(frames + 0, hash2, newblock);
2025                         dxtrace(dx_show_index("node", frames[1].entries));
2026                         dxtrace(dx_show_index("node",
2027                                ((struct dx_node *) bh2->b_data)->entries));
2028                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2029                         if (err)
2030                                 goto journal_error;
2031                         brelse (bh2);
2032                 } else {
2033                         dxtrace(printk(KERN_DEBUG
2034                                        "Creating second level index...\n"));
2035                         memcpy((char *) entries2, (char *) entries,
2036                                icount * sizeof(struct dx_entry));
2037                         dx_set_limit(entries2, dx_node_limit(dir));
2038
2039                         /* Set up root */
2040                         dx_set_count(entries, 1);
2041                         dx_set_block(entries + 0, newblock);
2042                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
2043
2044                         /* Add new access path frame */
2045                         frame = frames + 1;
2046                         frame->at = at = at - entries + entries2;
2047                         frame->entries = entries = entries2;
2048                         frame->bh = bh2;
2049                         err = ext4_journal_get_write_access(handle,
2050                                                              frame->bh);
2051                         if (err)
2052                                 goto journal_error;
2053                 }
2054                 err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
2055                 if (err) {
2056                         ext4_std_error(inode->i_sb, err);
2057                         goto cleanup;
2058                 }
2059         }
2060         de = do_split(handle, dir, &bh, frame, &hinfo);
2061         if (IS_ERR(de)) {
2062                 err = PTR_ERR(de);
2063                 goto cleanup;
2064         }
2065         err = add_dirent_to_buf(handle, dentry, inode, de, bh);
2066         goto cleanup;
2067
2068 journal_error:
2069         ext4_std_error(dir->i_sb, err);
2070 cleanup:
2071         brelse(bh);
2072         dx_release(frames);
2073         return err;
2074 }
2075
2076 /*
2077  * ext4_generic_delete_entry deletes a directory entry by merging it
2078  * with the previous entry
2079  */
2080 int ext4_generic_delete_entry(handle_t *handle,
2081                               struct inode *dir,
2082                               struct ext4_dir_entry_2 *de_del,
2083                               struct buffer_head *bh,
2084                               void *entry_buf,
2085                               int buf_size,
2086                               int csum_size)
2087 {
2088         struct ext4_dir_entry_2 *de, *pde;
2089         unsigned int blocksize = dir->i_sb->s_blocksize;
2090         int i;
2091
2092         i = 0;
2093         pde = NULL;
2094         de = (struct ext4_dir_entry_2 *)entry_buf;
2095         while (i < buf_size - csum_size) {
2096                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2097                                          bh->b_data, bh->b_size, i))
2098                         return -EIO;
2099                 if (de == de_del)  {
2100                         if (pde)
2101                                 pde->rec_len = ext4_rec_len_to_disk(
2102                                         ext4_rec_len_from_disk(pde->rec_len,
2103                                                                blocksize) +
2104                                         ext4_rec_len_from_disk(de->rec_len,
2105                                                                blocksize),
2106                                         blocksize);
2107                         else
2108                                 de->inode = 0;
2109                         dir->i_version++;
2110                         return 0;
2111                 }
2112                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2113                 pde = de;
2114                 de = ext4_next_entry(de, blocksize);
2115         }
2116         return -ENOENT;
2117 }
2118
2119 static int ext4_delete_entry(handle_t *handle,
2120                              struct inode *dir,
2121                              struct ext4_dir_entry_2 *de_del,
2122                              struct buffer_head *bh)
2123 {
2124         int err, csum_size = 0;
2125
2126         if (ext4_has_inline_data(dir)) {
2127                 int has_inline_data = 1;
2128                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2129                                                &has_inline_data);
2130                 if (has_inline_data)
2131                         return err;
2132         }
2133
2134         if (ext4_has_metadata_csum(dir->i_sb))
2135                 csum_size = sizeof(struct ext4_dir_entry_tail);
2136
2137         BUFFER_TRACE(bh, "get_write_access");
2138         err = ext4_journal_get_write_access(handle, bh);
2139         if (unlikely(err))
2140                 goto out;
2141
2142         err = ext4_generic_delete_entry(handle, dir, de_del,
2143                                         bh, bh->b_data,
2144                                         dir->i_sb->s_blocksize, csum_size);
2145         if (err)
2146                 goto out;
2147
2148         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2149         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2150         if (unlikely(err))
2151                 goto out;
2152
2153         return 0;
2154 out:
2155         if (err != -ENOENT)
2156                 ext4_std_error(dir->i_sb, err);
2157         return err;
2158 }
2159
2160 /*
2161  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
2162  * since this indicates that nlinks count was previously 1.
2163  */
2164 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2165 {
2166         inc_nlink(inode);
2167         if (is_dx(inode) && inode->i_nlink > 1) {
2168                 /* limit is 16-bit i_links_count */
2169                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
2170                         set_nlink(inode, 1);
2171                         EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb,
2172                                               EXT4_FEATURE_RO_COMPAT_DIR_NLINK);
2173                 }
2174         }
2175 }
2176
2177 /*
2178  * If a directory had nlink == 1, then we should let it be 1. This indicates
2179  * directory has >EXT4_LINK_MAX subdirs.
2180  */
2181 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2182 {
2183         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2184                 drop_nlink(inode);
2185 }
2186
2187
2188 static int ext4_add_nondir(handle_t *handle,
2189                 struct dentry *dentry, struct inode *inode)
2190 {
2191         int err = ext4_add_entry(handle, dentry, inode);
2192         if (!err) {
2193                 ext4_mark_inode_dirty(handle, inode);
2194                 unlock_new_inode(inode);
2195                 d_instantiate(dentry, inode);
2196                 return 0;
2197         }
2198         drop_nlink(inode);
2199         unlock_new_inode(inode);
2200         iput(inode);
2201         return err;
2202 }
2203
2204 /*
2205  * By the time this is called, we already have created
2206  * the directory cache entry for the new file, but it
2207  * is so far negative - it has no inode.
2208  *
2209  * If the create succeeds, we fill in the inode information
2210  * with d_instantiate().
2211  */
2212 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2213                        bool excl)
2214 {
2215         handle_t *handle;
2216         struct inode *inode;
2217         int err, credits, retries = 0;
2218
2219         dquot_initialize(dir);
2220
2221         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2222                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2223 retry:
2224         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2225                                             NULL, EXT4_HT_DIR, credits);
2226         handle = ext4_journal_current_handle();
2227         err = PTR_ERR(inode);
2228         if (!IS_ERR(inode)) {
2229                 inode->i_op = &ext4_file_inode_operations;
2230                 inode->i_fop = &ext4_file_operations;
2231                 ext4_set_aops(inode);
2232                 err = ext4_add_nondir(handle, dentry, inode);
2233                 if (!err && IS_DIRSYNC(dir))
2234                         ext4_handle_sync(handle);
2235         }
2236         if (handle)
2237                 ext4_journal_stop(handle);
2238         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2239                 goto retry;
2240         return err;
2241 }
2242
2243 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2244                       umode_t mode, dev_t rdev)
2245 {
2246         handle_t *handle;
2247         struct inode *inode;
2248         int err, credits, retries = 0;
2249
2250         if (!new_valid_dev(rdev))
2251                 return -EINVAL;
2252
2253         dquot_initialize(dir);
2254
2255         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2256                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2257 retry:
2258         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2259                                             NULL, EXT4_HT_DIR, credits);
2260         handle = ext4_journal_current_handle();
2261         err = PTR_ERR(inode);
2262         if (!IS_ERR(inode)) {
2263                 init_special_inode(inode, inode->i_mode, rdev);
2264                 inode->i_op = &ext4_special_inode_operations;
2265                 err = ext4_add_nondir(handle, dentry, inode);
2266                 if (!err && IS_DIRSYNC(dir))
2267                         ext4_handle_sync(handle);
2268         }
2269         if (handle)
2270                 ext4_journal_stop(handle);
2271         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2272                 goto retry;
2273         return err;
2274 }
2275
2276 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2277 {
2278         handle_t *handle;
2279         struct inode *inode;
2280         int err, retries = 0;
2281
2282         dquot_initialize(dir);
2283
2284 retry:
2285         inode = ext4_new_inode_start_handle(dir, mode,
2286                                             NULL, 0, NULL,
2287                                             EXT4_HT_DIR,
2288                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2289                           4 + EXT4_XATTR_TRANS_BLOCKS);
2290         handle = ext4_journal_current_handle();
2291         err = PTR_ERR(inode);
2292         if (!IS_ERR(inode)) {
2293                 inode->i_op = &ext4_file_inode_operations;
2294                 inode->i_fop = &ext4_file_operations;
2295                 ext4_set_aops(inode);
2296                 d_tmpfile(dentry, inode);
2297                 err = ext4_orphan_add(handle, inode);
2298                 if (err)
2299                         goto err_unlock_inode;
2300                 mark_inode_dirty(inode);
2301                 unlock_new_inode(inode);
2302         }
2303         if (handle)
2304                 ext4_journal_stop(handle);
2305         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2306                 goto retry;
2307         return err;
2308 err_unlock_inode:
2309         ext4_journal_stop(handle);
2310         unlock_new_inode(inode);
2311         return err;
2312 }
2313
2314 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2315                           struct ext4_dir_entry_2 *de,
2316                           int blocksize, int csum_size,
2317                           unsigned int parent_ino, int dotdot_real_len)
2318 {
2319         de->inode = cpu_to_le32(inode->i_ino);
2320         de->name_len = 1;
2321         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2322                                            blocksize);
2323         strcpy(de->name, ".");
2324         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2325
2326         de = ext4_next_entry(de, blocksize);
2327         de->inode = cpu_to_le32(parent_ino);
2328         de->name_len = 2;
2329         if (!dotdot_real_len)
2330                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2331                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2332                                         blocksize);
2333         else
2334                 de->rec_len = ext4_rec_len_to_disk(
2335                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2336         strcpy(de->name, "..");
2337         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2338
2339         return ext4_next_entry(de, blocksize);
2340 }
2341
2342 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2343                              struct inode *inode)
2344 {
2345         struct buffer_head *dir_block = NULL;
2346         struct ext4_dir_entry_2 *de;
2347         struct ext4_dir_entry_tail *t;
2348         ext4_lblk_t block = 0;
2349         unsigned int blocksize = dir->i_sb->s_blocksize;
2350         int csum_size = 0;
2351         int err;
2352
2353         if (ext4_has_metadata_csum(dir->i_sb))
2354                 csum_size = sizeof(struct ext4_dir_entry_tail);
2355
2356         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2357                 err = ext4_try_create_inline_dir(handle, dir, inode);
2358                 if (err < 0 && err != -ENOSPC)
2359                         goto out;
2360                 if (!err)
2361                         goto out;
2362         }
2363
2364         inode->i_size = 0;
2365         dir_block = ext4_append(handle, inode, &block);
2366         if (IS_ERR(dir_block))
2367                 return PTR_ERR(dir_block);
2368         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2369         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2370         set_nlink(inode, 2);
2371         if (csum_size) {
2372                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2373                 initialize_dirent_tail(t, blocksize);
2374         }
2375
2376         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2377         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2378         if (err)
2379                 goto out;
2380         set_buffer_verified(dir_block);
2381 out:
2382         brelse(dir_block);
2383         return err;
2384 }
2385
2386 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2387 {
2388         handle_t *handle;
2389         struct inode *inode;
2390         int err, credits, retries = 0;
2391
2392         if (EXT4_DIR_LINK_MAX(dir))
2393                 return -EMLINK;
2394
2395         dquot_initialize(dir);
2396
2397         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2398                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2399 retry:
2400         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2401                                             &dentry->d_name,
2402                                             0, NULL, EXT4_HT_DIR, credits);
2403         handle = ext4_journal_current_handle();
2404         err = PTR_ERR(inode);
2405         if (IS_ERR(inode))
2406                 goto out_stop;
2407
2408         inode->i_op = &ext4_dir_inode_operations;
2409         inode->i_fop = &ext4_dir_operations;
2410         err = ext4_init_new_dir(handle, dir, inode);
2411         if (err)
2412                 goto out_clear_inode;
2413         err = ext4_mark_inode_dirty(handle, inode);
2414         if (!err)
2415                 err = ext4_add_entry(handle, dentry, inode);
2416         if (err) {
2417 out_clear_inode:
2418                 clear_nlink(inode);
2419                 unlock_new_inode(inode);
2420                 ext4_mark_inode_dirty(handle, inode);
2421                 iput(inode);
2422                 goto out_stop;
2423         }
2424         ext4_inc_count(handle, dir);
2425         ext4_update_dx_flag(dir);
2426         err = ext4_mark_inode_dirty(handle, dir);
2427         if (err)
2428                 goto out_clear_inode;
2429         unlock_new_inode(inode);
2430         d_instantiate(dentry, inode);
2431         if (IS_DIRSYNC(dir))
2432                 ext4_handle_sync(handle);
2433
2434 out_stop:
2435         if (handle)
2436                 ext4_journal_stop(handle);
2437         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2438                 goto retry;
2439         return err;
2440 }
2441
2442 /*
2443  * routine to check that the specified directory is empty (for rmdir)
2444  */
2445 static int empty_dir(struct inode *inode)
2446 {
2447         unsigned int offset;
2448         struct buffer_head *bh;
2449         struct ext4_dir_entry_2 *de, *de1;
2450         struct super_block *sb;
2451         int err = 0;
2452
2453         if (ext4_has_inline_data(inode)) {
2454                 int has_inline_data = 1;
2455
2456                 err = empty_inline_dir(inode, &has_inline_data);
2457                 if (has_inline_data)
2458                         return err;
2459         }
2460
2461         sb = inode->i_sb;
2462         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2463                 EXT4_ERROR_INODE(inode, "invalid size");
2464                 return 1;
2465         }
2466         bh = ext4_read_dirblock(inode, 0, EITHER);
2467         if (IS_ERR(bh))
2468                 return 1;
2469
2470         de = (struct ext4_dir_entry_2 *) bh->b_data;
2471         de1 = ext4_next_entry(de, sb->s_blocksize);
2472         if (le32_to_cpu(de->inode) != inode->i_ino ||
2473                         !le32_to_cpu(de1->inode) ||
2474                         strcmp(".", de->name) ||
2475                         strcmp("..", de1->name)) {
2476                 ext4_warning(inode->i_sb,
2477                              "bad directory (dir #%lu) - no `.' or `..'",
2478                              inode->i_ino);
2479                 brelse(bh);
2480                 return 1;
2481         }
2482         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2483                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2484         de = ext4_next_entry(de1, sb->s_blocksize);
2485         while (offset < inode->i_size) {
2486                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2487                         unsigned int lblock;
2488                         err = 0;
2489                         brelse(bh);
2490                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2491                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2492                         if (IS_ERR(bh))
2493                                 return 1;
2494                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2495                 }
2496                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2497                                          bh->b_data, bh->b_size, offset)) {
2498                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2499                                                          sb->s_blocksize);
2500                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2501                         continue;
2502                 }
2503                 if (le32_to_cpu(de->inode)) {
2504                         brelse(bh);
2505                         return 0;
2506                 }
2507                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2508                 de = ext4_next_entry(de, sb->s_blocksize);
2509         }
2510         brelse(bh);
2511         return 1;
2512 }
2513
2514 /*
2515  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2516  * such inodes, starting at the superblock, in case we crash before the
2517  * file is closed/deleted, or in case the inode truncate spans multiple
2518  * transactions and the last transaction is not recovered after a crash.
2519  *
2520  * At filesystem recovery time, we walk this list deleting unlinked
2521  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2522  *
2523  * Orphan list manipulation functions must be called under i_mutex unless
2524  * we are just creating the inode or deleting it.
2525  */
2526 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2527 {
2528         struct super_block *sb = inode->i_sb;
2529         struct ext4_sb_info *sbi = EXT4_SB(sb);
2530         struct ext4_iloc iloc;
2531         int err = 0, rc;
2532         bool dirty = false;
2533
2534         if (!sbi->s_journal || is_bad_inode(inode))
2535                 return 0;
2536
2537         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2538                      !mutex_is_locked(&inode->i_mutex));
2539         /*
2540          * Exit early if inode already is on orphan list. This is a big speedup
2541          * since we don't have to contend on the global s_orphan_lock.
2542          */
2543         if (!list_empty(&EXT4_I(inode)->i_orphan))
2544                 return 0;
2545
2546         /*
2547          * Orphan handling is only valid for files with data blocks
2548          * being truncated, or files being unlinked. Note that we either
2549          * hold i_mutex, or the inode can not be referenced from outside,
2550          * so i_nlink should not be bumped due to race
2551          */
2552         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2553                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2554
2555         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2556         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2557         if (err)
2558                 goto out;
2559
2560         err = ext4_reserve_inode_write(handle, inode, &iloc);
2561         if (err)
2562                 goto out;
2563
2564         mutex_lock(&sbi->s_orphan_lock);
2565         /*
2566          * Due to previous errors inode may be already a part of on-disk
2567          * orphan list. If so skip on-disk list modification.
2568          */
2569         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2570             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2571                 /* Insert this inode at the head of the on-disk orphan list */
2572                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2573                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2574                 dirty = true;
2575         }
2576         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2577         mutex_unlock(&sbi->s_orphan_lock);
2578
2579         if (dirty) {
2580                 err = ext4_handle_dirty_super(handle, sb);
2581                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2582                 if (!err)
2583                         err = rc;
2584                 if (err) {
2585                         /*
2586                          * We have to remove inode from in-memory list if
2587                          * addition to on disk orphan list failed. Stray orphan
2588                          * list entries can cause panics at unmount time.
2589                          */
2590                         mutex_lock(&sbi->s_orphan_lock);
2591                         list_del(&EXT4_I(inode)->i_orphan);
2592                         mutex_unlock(&sbi->s_orphan_lock);
2593                 }
2594         }
2595         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2596         jbd_debug(4, "orphan inode %lu will point to %d\n",
2597                         inode->i_ino, NEXT_ORPHAN(inode));
2598 out:
2599         ext4_std_error(sb, err);
2600         return err;
2601 }
2602
2603 /*
2604  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2605  * of such inodes stored on disk, because it is finally being cleaned up.
2606  */
2607 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2608 {
2609         struct list_head *prev;
2610         struct ext4_inode_info *ei = EXT4_I(inode);
2611         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2612         __u32 ino_next;
2613         struct ext4_iloc iloc;
2614         int err = 0;
2615
2616         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2617                 return 0;
2618
2619         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2620                      !mutex_is_locked(&inode->i_mutex));
2621         /* Do this quick check before taking global s_orphan_lock. */
2622         if (list_empty(&ei->i_orphan))
2623                 return 0;
2624
2625         if (handle) {
2626                 /* Grab inode buffer early before taking global s_orphan_lock */
2627                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2628         }
2629
2630         mutex_lock(&sbi->s_orphan_lock);
2631         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2632
2633         prev = ei->i_orphan.prev;
2634         list_del_init(&ei->i_orphan);
2635
2636         /* If we're on an error path, we may not have a valid
2637          * transaction handle with which to update the orphan list on
2638          * disk, but we still need to remove the inode from the linked
2639          * list in memory. */
2640         if (!handle || err) {
2641                 mutex_unlock(&sbi->s_orphan_lock);
2642                 goto out_err;
2643         }
2644
2645         ino_next = NEXT_ORPHAN(inode);
2646         if (prev == &sbi->s_orphan) {
2647                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2648                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2649                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2650                 if (err) {
2651                         mutex_unlock(&sbi->s_orphan_lock);
2652                         goto out_brelse;
2653                 }
2654                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2655                 mutex_unlock(&sbi->s_orphan_lock);
2656                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2657         } else {
2658                 struct ext4_iloc iloc2;
2659                 struct inode *i_prev =
2660                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2661
2662                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2663                           i_prev->i_ino, ino_next);
2664                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2665                 if (err) {
2666                         mutex_unlock(&sbi->s_orphan_lock);
2667                         goto out_brelse;
2668                 }
2669                 NEXT_ORPHAN(i_prev) = ino_next;
2670                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2671                 mutex_unlock(&sbi->s_orphan_lock);
2672         }
2673         if (err)
2674                 goto out_brelse;
2675         NEXT_ORPHAN(inode) = 0;
2676         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2677 out_err:
2678         ext4_std_error(inode->i_sb, err);
2679         return err;
2680
2681 out_brelse:
2682         brelse(iloc.bh);
2683         goto out_err;
2684 }
2685
2686 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2687 {
2688         int retval;
2689         struct inode *inode;
2690         struct buffer_head *bh;
2691         struct ext4_dir_entry_2 *de;
2692         handle_t *handle = NULL;
2693
2694         /* Initialize quotas before so that eventual writes go in
2695          * separate transaction */
2696         dquot_initialize(dir);
2697         dquot_initialize(dentry->d_inode);
2698
2699         retval = -ENOENT;
2700         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2701         if (IS_ERR(bh))
2702                 return PTR_ERR(bh);
2703         if (!bh)
2704                 goto end_rmdir;
2705
2706         inode = dentry->d_inode;
2707
2708         retval = -EIO;
2709         if (le32_to_cpu(de->inode) != inode->i_ino)
2710                 goto end_rmdir;
2711
2712         retval = -ENOTEMPTY;
2713         if (!empty_dir(inode))
2714                 goto end_rmdir;
2715
2716         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2717                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2718         if (IS_ERR(handle)) {
2719                 retval = PTR_ERR(handle);
2720                 handle = NULL;
2721                 goto end_rmdir;
2722         }
2723
2724         if (IS_DIRSYNC(dir))
2725                 ext4_handle_sync(handle);
2726
2727         retval = ext4_delete_entry(handle, dir, de, bh);
2728         if (retval)
2729                 goto end_rmdir;
2730         if (!EXT4_DIR_LINK_EMPTY(inode))
2731                 ext4_warning(inode->i_sb,
2732                              "empty directory has too many links (%d)",
2733                              inode->i_nlink);
2734         inode->i_version++;
2735         clear_nlink(inode);
2736         /* There's no need to set i_disksize: the fact that i_nlink is
2737          * zero will ensure that the right thing happens during any
2738          * recovery. */
2739         inode->i_size = 0;
2740         ext4_orphan_add(handle, inode);
2741         inode->i_ctime = dir->i_ctime = dir->i_mtime = ext4_current_time(inode);
2742         ext4_mark_inode_dirty(handle, inode);
2743         ext4_dec_count(handle, dir);
2744         ext4_update_dx_flag(dir);
2745         ext4_mark_inode_dirty(handle, dir);
2746
2747 end_rmdir:
2748         brelse(bh);
2749         if (handle)
2750                 ext4_journal_stop(handle);
2751         return retval;
2752 }
2753
2754 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2755 {
2756         int retval;
2757         struct inode *inode;
2758         struct buffer_head *bh;
2759         struct ext4_dir_entry_2 *de;
2760         handle_t *handle = NULL;
2761
2762         trace_ext4_unlink_enter(dir, dentry);
2763         /* Initialize quotas before so that eventual writes go
2764          * in separate transaction */
2765         dquot_initialize(dir);
2766         dquot_initialize(dentry->d_inode);
2767
2768         retval = -ENOENT;
2769         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2770         if (IS_ERR(bh))
2771                 return PTR_ERR(bh);
2772         if (!bh)
2773                 goto end_unlink;
2774
2775         inode = dentry->d_inode;
2776
2777         retval = -EIO;
2778         if (le32_to_cpu(de->inode) != inode->i_ino)
2779                 goto end_unlink;
2780
2781         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2782                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2783         if (IS_ERR(handle)) {
2784                 retval = PTR_ERR(handle);
2785                 handle = NULL;
2786                 goto end_unlink;
2787         }
2788
2789         if (IS_DIRSYNC(dir))
2790                 ext4_handle_sync(handle);
2791
2792         if (!inode->i_nlink) {
2793                 ext4_warning(inode->i_sb,
2794                              "Deleting nonexistent file (%lu), %d",
2795                              inode->i_ino, inode->i_nlink);
2796                 set_nlink(inode, 1);
2797         }
2798         retval = ext4_delete_entry(handle, dir, de, bh);
2799         if (retval)
2800                 goto end_unlink;
2801         dir->i_ctime = dir->i_mtime = ext4_current_time(dir);
2802         ext4_update_dx_flag(dir);
2803         ext4_mark_inode_dirty(handle, dir);
2804         drop_nlink(inode);
2805         if (!inode->i_nlink)
2806                 ext4_orphan_add(handle, inode);
2807         inode->i_ctime = ext4_current_time(inode);
2808         ext4_mark_inode_dirty(handle, inode);
2809         retval = 0;
2810
2811 end_unlink:
2812         brelse(bh);
2813         if (handle)
2814                 ext4_journal_stop(handle);
2815         trace_ext4_unlink_exit(dentry, retval);
2816         return retval;
2817 }
2818
2819 static int ext4_symlink(struct inode *dir,
2820                         struct dentry *dentry, const char *symname)
2821 {
2822         handle_t *handle;
2823         struct inode *inode;
2824         int l, err, retries = 0;
2825         int credits;
2826
2827         l = strlen(symname)+1;
2828         if (l > dir->i_sb->s_blocksize)
2829                 return -ENAMETOOLONG;
2830
2831         dquot_initialize(dir);
2832
2833         if (l > EXT4_N_BLOCKS * 4) {
2834                 /*
2835                  * For non-fast symlinks, we just allocate inode and put it on
2836                  * orphan list in the first transaction => we need bitmap,
2837                  * group descriptor, sb, inode block, quota blocks, and
2838                  * possibly selinux xattr blocks.
2839                  */
2840                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2841                           EXT4_XATTR_TRANS_BLOCKS;
2842         } else {
2843                 /*
2844                  * Fast symlink. We have to add entry to directory
2845                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
2846                  * allocate new inode (bitmap, group descriptor, inode block,
2847                  * quota blocks, sb is already counted in previous macros).
2848                  */
2849                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2850                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
2851         }
2852 retry:
2853         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
2854                                             &dentry->d_name, 0, NULL,
2855                                             EXT4_HT_DIR, credits);
2856         handle = ext4_journal_current_handle();
2857         err = PTR_ERR(inode);
2858         if (IS_ERR(inode))
2859                 goto out_stop;
2860
2861         if (l > EXT4_N_BLOCKS * 4) {
2862                 inode->i_op = &ext4_symlink_inode_operations;
2863                 ext4_set_aops(inode);
2864                 /*
2865                  * We cannot call page_symlink() with transaction started
2866                  * because it calls into ext4_write_begin() which can wait
2867                  * for transaction commit if we are running out of space
2868                  * and thus we deadlock. So we have to stop transaction now
2869                  * and restart it when symlink contents is written.
2870                  * 
2871                  * To keep fs consistent in case of crash, we have to put inode
2872                  * to orphan list in the mean time.
2873                  */
2874                 drop_nlink(inode);
2875                 err = ext4_orphan_add(handle, inode);
2876                 ext4_journal_stop(handle);
2877                 if (err)
2878                         goto err_drop_inode;
2879                 err = __page_symlink(inode, symname, l, 1);
2880                 if (err)
2881                         goto err_drop_inode;
2882                 /*
2883                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
2884                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
2885                  */
2886                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
2887                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2888                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
2889                 if (IS_ERR(handle)) {
2890                         err = PTR_ERR(handle);
2891                         goto err_drop_inode;
2892                 }
2893                 set_nlink(inode, 1);
2894                 err = ext4_orphan_del(handle, inode);
2895                 if (err) {
2896                         ext4_journal_stop(handle);
2897                         clear_nlink(inode);
2898                         goto err_drop_inode;
2899                 }
2900         } else {
2901                 /* clear the extent format for fast symlink */
2902                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
2903                 inode->i_op = &ext4_fast_symlink_inode_operations;
2904                 memcpy((char *)&EXT4_I(inode)->i_data, symname, l);
2905                 inode->i_size = l-1;
2906         }
2907         EXT4_I(inode)->i_disksize = inode->i_size;
2908         err = ext4_add_nondir(handle, dentry, inode);
2909         if (!err && IS_DIRSYNC(dir))
2910                 ext4_handle_sync(handle);
2911
2912 out_stop:
2913         if (handle)
2914                 ext4_journal_stop(handle);
2915         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2916                 goto retry;
2917         return err;
2918 err_drop_inode:
2919         unlock_new_inode(inode);
2920         iput(inode);
2921         return err;
2922 }
2923
2924 static int ext4_link(struct dentry *old_dentry,
2925                      struct inode *dir, struct dentry *dentry)
2926 {
2927         handle_t *handle;
2928         struct inode *inode = old_dentry->d_inode;
2929         int err, retries = 0;
2930
2931         if (inode->i_nlink >= EXT4_LINK_MAX)
2932                 return -EMLINK;
2933
2934         dquot_initialize(dir);
2935
2936 retry:
2937         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2938                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2939                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
2940         if (IS_ERR(handle))
2941                 return PTR_ERR(handle);
2942
2943         if (IS_DIRSYNC(dir))
2944                 ext4_handle_sync(handle);
2945
2946         inode->i_ctime = ext4_current_time(inode);
2947         ext4_inc_count(handle, inode);
2948         ihold(inode);
2949
2950         err = ext4_add_entry(handle, dentry, inode);
2951         if (!err) {
2952                 ext4_mark_inode_dirty(handle, inode);
2953                 /* this can happen only for tmpfile being
2954                  * linked the first time
2955                  */
2956                 if (inode->i_nlink == 1)
2957                         ext4_orphan_del(handle, inode);
2958                 d_instantiate(dentry, inode);
2959         } else {
2960                 drop_nlink(inode);
2961                 iput(inode);
2962         }
2963         ext4_journal_stop(handle);
2964         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2965                 goto retry;
2966         return err;
2967 }
2968
2969
2970 /*
2971  * Try to find buffer head where contains the parent block.
2972  * It should be the inode block if it is inlined or the 1st block
2973  * if it is a normal dir.
2974  */
2975 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
2976                                         struct inode *inode,
2977                                         int *retval,
2978                                         struct ext4_dir_entry_2 **parent_de,
2979                                         int *inlined)
2980 {
2981         struct buffer_head *bh;
2982
2983         if (!ext4_has_inline_data(inode)) {
2984                 bh = ext4_read_dirblock(inode, 0, EITHER);
2985                 if (IS_ERR(bh)) {
2986                         *retval = PTR_ERR(bh);
2987                         return NULL;
2988                 }
2989                 *parent_de = ext4_next_entry(
2990                                         (struct ext4_dir_entry_2 *)bh->b_data,
2991                                         inode->i_sb->s_blocksize);
2992                 return bh;
2993         }
2994
2995         *inlined = 1;
2996         return ext4_get_first_inline_block(inode, parent_de, retval);
2997 }
2998
2999 struct ext4_renament {
3000         struct inode *dir;
3001         struct dentry *dentry;
3002         struct inode *inode;
3003         bool is_dir;
3004         int dir_nlink_delta;
3005
3006         /* entry for "dentry" */
3007         struct buffer_head *bh;
3008         struct ext4_dir_entry_2 *de;
3009         int inlined;
3010
3011         /* entry for ".." in inode if it's a directory */
3012         struct buffer_head *dir_bh;
3013         struct ext4_dir_entry_2 *parent_de;
3014         int dir_inlined;
3015 };
3016
3017 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3018 {
3019         int retval;
3020
3021         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3022                                               &retval, &ent->parent_de,
3023                                               &ent->dir_inlined);
3024         if (!ent->dir_bh)
3025                 return retval;
3026         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3027                 return -EIO;
3028         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3029         return ext4_journal_get_write_access(handle, ent->dir_bh);
3030 }
3031
3032 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3033                                   unsigned dir_ino)
3034 {
3035         int retval;
3036
3037         ent->parent_de->inode = cpu_to_le32(dir_ino);
3038         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3039         if (!ent->dir_inlined) {
3040                 if (is_dx(ent->inode)) {
3041                         retval = ext4_handle_dirty_dx_node(handle,
3042                                                            ent->inode,
3043                                                            ent->dir_bh);
3044                 } else {
3045                         retval = ext4_handle_dirty_dirent_node(handle,
3046                                                                ent->inode,
3047                                                                ent->dir_bh);
3048                 }
3049         } else {
3050                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3051         }
3052         if (retval) {
3053                 ext4_std_error(ent->dir->i_sb, retval);
3054                 return retval;
3055         }
3056         return 0;
3057 }
3058
3059 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3060                        unsigned ino, unsigned file_type)
3061 {
3062         int retval;
3063
3064         BUFFER_TRACE(ent->bh, "get write access");
3065         retval = ext4_journal_get_write_access(handle, ent->bh);
3066         if (retval)
3067                 return retval;
3068         ent->de->inode = cpu_to_le32(ino);
3069         if (EXT4_HAS_INCOMPAT_FEATURE(ent->dir->i_sb,
3070                                       EXT4_FEATURE_INCOMPAT_FILETYPE))
3071                 ent->de->file_type = file_type;
3072         ent->dir->i_version++;
3073         ent->dir->i_ctime = ent->dir->i_mtime =
3074                 ext4_current_time(ent->dir);
3075         ext4_mark_inode_dirty(handle, ent->dir);
3076         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3077         if (!ent->inlined) {
3078                 retval = ext4_handle_dirty_dirent_node(handle,
3079                                                        ent->dir, ent->bh);
3080                 if (unlikely(retval)) {
3081                         ext4_std_error(ent->dir->i_sb, retval);
3082                         return retval;
3083                 }
3084         }
3085         brelse(ent->bh);
3086         ent->bh = NULL;
3087
3088         return 0;
3089 }
3090
3091 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3092                                   const struct qstr *d_name)
3093 {
3094         int retval = -ENOENT;
3095         struct buffer_head *bh;
3096         struct ext4_dir_entry_2 *de;
3097
3098         bh = ext4_find_entry(dir, d_name, &de, NULL);
3099         if (IS_ERR(bh))
3100                 return PTR_ERR(bh);
3101         if (bh) {
3102                 retval = ext4_delete_entry(handle, dir, de, bh);
3103                 brelse(bh);
3104         }
3105         return retval;
3106 }
3107
3108 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3109                                int force_reread)
3110 {
3111         int retval;
3112         /*
3113          * ent->de could have moved from under us during htree split, so make
3114          * sure that we are deleting the right entry.  We might also be pointing
3115          * to a stale entry in the unused part of ent->bh so just checking inum
3116          * and the name isn't enough.
3117          */
3118         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3119             ent->de->name_len != ent->dentry->d_name.len ||
3120             strncmp(ent->de->name, ent->dentry->d_name.name,
3121                     ent->de->name_len) ||
3122             force_reread) {
3123                 retval = ext4_find_delete_entry(handle, ent->dir,
3124                                                 &ent->dentry->d_name);
3125         } else {
3126                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3127                 if (retval == -ENOENT) {
3128                         retval = ext4_find_delete_entry(handle, ent->dir,
3129                                                         &ent->dentry->d_name);
3130                 }
3131         }
3132
3133         if (retval) {
3134                 ext4_warning(ent->dir->i_sb,
3135                                 "Deleting old file (%lu), %d, error=%d",
3136                                 ent->dir->i_ino, ent->dir->i_nlink, retval);
3137         }
3138 }
3139
3140 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3141 {
3142         if (ent->dir_nlink_delta) {
3143                 if (ent->dir_nlink_delta == -1)
3144                         ext4_dec_count(handle, ent->dir);
3145                 else
3146                         ext4_inc_count(handle, ent->dir);
3147                 ext4_mark_inode_dirty(handle, ent->dir);
3148         }
3149 }
3150
3151 /*
3152  * Anybody can rename anything with this: the permission checks are left to the
3153  * higher-level routines.
3154  *
3155  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3156  * while new_{dentry,inode) refers to the destination dentry/inode
3157  * This comes from rename(const char *oldpath, const char *newpath)
3158  */
3159 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3160                        struct inode *new_dir, struct dentry *new_dentry)
3161 {
3162         handle_t *handle = NULL;
3163         struct ext4_renament old = {
3164                 .dir = old_dir,
3165                 .dentry = old_dentry,
3166                 .inode = old_dentry->d_inode,
3167         };
3168         struct ext4_renament new = {
3169                 .dir = new_dir,
3170                 .dentry = new_dentry,
3171                 .inode = new_dentry->d_inode,
3172         };
3173         int force_reread;
3174         int retval;
3175
3176         dquot_initialize(old.dir);
3177         dquot_initialize(new.dir);
3178
3179         /* Initialize quotas before so that eventual writes go
3180          * in separate transaction */
3181         if (new.inode)
3182                 dquot_initialize(new.inode);
3183
3184         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3185         if (IS_ERR(old.bh))
3186                 return PTR_ERR(old.bh);
3187         /*
3188          *  Check for inode number is _not_ due to possible IO errors.
3189          *  We might rmdir the source, keep it as pwd of some process
3190          *  and merrily kill the link to whatever was created under the
3191          *  same name. Goodbye sticky bit ;-<
3192          */
3193         retval = -ENOENT;
3194         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3195                 goto end_rename;
3196
3197         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3198                                  &new.de, &new.inlined);
3199         i