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Linux/fs/ext4/namei.c

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  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/time.h>
 30 #include <linux/fcntl.h>
 31 #include <linux/stat.h>
 32 #include <linux/string.h>
 33 #include <linux/quotaops.h>
 34 #include <linux/buffer_head.h>
 35 #include <linux/bio.h>
 36 #include "ext4.h"
 37 #include "ext4_jbd2.h"
 38 
 39 #include "xattr.h"
 40 #include "acl.h"
 41 
 42 #include <trace/events/ext4.h>
 43 /*
 44  * define how far ahead to read directories while searching them.
 45  */
 46 #define NAMEI_RA_CHUNKS  2
 47 #define NAMEI_RA_BLOCKS  4
 48 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
 49 
 50 static struct buffer_head *ext4_append(handle_t *handle,
 51                                         struct inode *inode,
 52                                         ext4_lblk_t *block)
 53 {
 54         struct buffer_head *bh;
 55         int err;
 56 
 57         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
 58                      ((inode->i_size >> 10) >=
 59                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
 60                 return ERR_PTR(-ENOSPC);
 61 
 62         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
 63 
 64         bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
 65         if (IS_ERR(bh))
 66                 return bh;
 67         inode->i_size += inode->i_sb->s_blocksize;
 68         EXT4_I(inode)->i_disksize = inode->i_size;
 69         BUFFER_TRACE(bh, "get_write_access");
 70         err = ext4_journal_get_write_access(handle, bh);
 71         if (err) {
 72                 brelse(bh);
 73                 ext4_std_error(inode->i_sb, err);
 74                 return ERR_PTR(err);
 75         }
 76         return bh;
 77 }
 78 
 79 static int ext4_dx_csum_verify(struct inode *inode,
 80                                struct ext4_dir_entry *dirent);
 81 
 82 typedef enum {
 83         EITHER, INDEX, DIRENT
 84 } dirblock_type_t;
 85 
 86 #define ext4_read_dirblock(inode, block, type) \
 87         __ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
 88 
 89 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
 90                                                 ext4_lblk_t block,
 91                                                 dirblock_type_t type,
 92                                                 const char *func,
 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                                "inode #%lu: lblock %lu: comm %s: "
103                                "error %ld reading directory block",
104                                inode->i_ino, (unsigned long)block,
105                                current->comm, PTR_ERR(bh));
106 
107                 return bh;
108         }
109         if (!bh) {
110                 ext4_error_inode(inode, func, line, block,
111                                  "Directory hole found");
112                 return ERR_PTR(-EIO);
113         }
114         dirent = (struct ext4_dir_entry *) bh->b_data;
115         /* Determine whether or not we have an index block */
116         if (is_dx(inode)) {
117                 if (block == 0)
118                         is_dx_block = 1;
119                 else if (ext4_rec_len_from_disk(dirent->rec_len,
120                                                 inode->i_sb->s_blocksize) ==
121                          inode->i_sb->s_blocksize)
122                         is_dx_block = 1;
123         }
124         if (!is_dx_block && type == INDEX) {
125                 ext4_error_inode(inode, func, line, block,
126                        "directory leaf block found instead of index block");
127                 return ERR_PTR(-EIO);
128         }
129         if (!ext4_has_metadata_csum(inode->i_sb) ||
130             buffer_verified(bh))
131                 return bh;
132 
133         /*
134          * An empty leaf block can get mistaken for a index block; for
135          * this reason, we can only check the index checksum when the
136          * caller is sure it should be an index block.
137          */
138         if (is_dx_block && type == INDEX) {
139                 if (ext4_dx_csum_verify(inode, dirent))
140                         set_buffer_verified(bh);
141                 else {
142                         ext4_error_inode(inode, func, line, block,
143                                          "Directory index failed checksum");
144                         brelse(bh);
145                         return ERR_PTR(-EIO);
146                 }
147         }
148         if (!is_dx_block) {
149                 if (ext4_dirent_csum_verify(inode, dirent))
150                         set_buffer_verified(bh);
151                 else {
152                         ext4_error_inode(inode, func, line, block,
153                                          "Directory block failed checksum");
154                         brelse(bh);
155                         return ERR_PTR(-EIO);
156                 }
157         }
158         return bh;
159 }
160 
161 #ifndef assert
162 #define assert(test) J_ASSERT(test)
163 #endif
164 
165 #ifdef DX_DEBUG
166 #define dxtrace(command) command
167 #else
168 #define dxtrace(command)
169 #endif
170 
171 struct fake_dirent
172 {
173         __le32 inode;
174         __le16 rec_len;
175         u8 name_len;
176         u8 file_type;
177 };
178 
179 struct dx_countlimit
180 {
181         __le16 limit;
182         __le16 count;
183 };
184 
185 struct dx_entry
186 {
187         __le32 hash;
188         __le32 block;
189 };
190 
191 /*
192  * dx_root_info is laid out so that if it should somehow get overlaid by a
193  * dirent the two low bits of the hash version will be zero.  Therefore, the
194  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
195  */
196 
197 struct dx_root
198 {
199         struct fake_dirent dot;
200         char dot_name[4];
201         struct fake_dirent dotdot;
202         char dotdot_name[4];
203         struct dx_root_info
204         {
205                 __le32 reserved_zero;
206                 u8 hash_version;
207                 u8 info_length; /* 8 */
208                 u8 indirect_levels;
209                 u8 unused_flags;
210         }
211         info;
212         struct dx_entry entries[0];
213 };
214 
215 struct dx_node
216 {
217         struct fake_dirent fake;
218         struct dx_entry entries[0];
219 };
220 
221 
222 struct dx_frame
223 {
224         struct buffer_head *bh;
225         struct dx_entry *entries;
226         struct dx_entry *at;
227 };
228 
229 struct dx_map_entry
230 {
231         u32 hash;
232         u16 offs;
233         u16 size;
234 };
235 
236 /*
237  * This goes at the end of each htree block.
238  */
239 struct dx_tail {
240         u32 dt_reserved;
241         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
242 };
243 
244 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
245 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
246 static inline unsigned dx_get_hash(struct dx_entry *entry);
247 static void dx_set_hash(struct dx_entry *entry, unsigned value);
248 static unsigned dx_get_count(struct dx_entry *entries);
249 static unsigned dx_get_limit(struct dx_entry *entries);
250 static void dx_set_count(struct dx_entry *entries, unsigned value);
251 static void dx_set_limit(struct dx_entry *entries, unsigned value);
252 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
253 static unsigned dx_node_limit(struct inode *dir);
254 static struct dx_frame *dx_probe(struct ext4_filename *fname,
255                                  struct inode *dir,
256                                  struct dx_hash_info *hinfo,
257                                  struct dx_frame *frame);
258 static void dx_release(struct dx_frame *frames);
259 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
260                        unsigned blocksize, struct dx_hash_info *hinfo,
261                        struct dx_map_entry map[]);
262 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
263 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
264                 struct dx_map_entry *offsets, int count, unsigned blocksize);
265 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
266 static void dx_insert_block(struct dx_frame *frame,
267                                         u32 hash, ext4_lblk_t block);
268 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
269                                  struct dx_frame *frame,
270                                  struct dx_frame *frames,
271                                  __u32 *start_hash);
272 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
273                 struct ext4_filename *fname,
274                 struct ext4_dir_entry_2 **res_dir);
275 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
276                              struct dentry *dentry, struct inode *inode);
277 
278 /* checksumming functions */
279 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
280                             unsigned int blocksize)
281 {
282         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
283         t->det_rec_len = ext4_rec_len_to_disk(
284                         sizeof(struct ext4_dir_entry_tail), blocksize);
285         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
286 }
287 
288 /* Walk through a dirent block to find a checksum "dirent" at the tail */
289 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
290                                                    struct ext4_dir_entry *de)
291 {
292         struct ext4_dir_entry_tail *t;
293 
294 #ifdef PARANOID
295         struct ext4_dir_entry *d, *top;
296 
297         d = de;
298         top = (struct ext4_dir_entry *)(((void *)de) +
299                 (EXT4_BLOCK_SIZE(inode->i_sb) -
300                 sizeof(struct ext4_dir_entry_tail)));
301         while (d < top && d->rec_len)
302                 d = (struct ext4_dir_entry *)(((void *)d) +
303                     le16_to_cpu(d->rec_len));
304 
305         if (d != top)
306                 return NULL;
307 
308         t = (struct ext4_dir_entry_tail *)d;
309 #else
310         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
311 #endif
312 
313         if (t->det_reserved_zero1 ||
314             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
315             t->det_reserved_zero2 ||
316             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
317                 return NULL;
318 
319         return t;
320 }
321 
322 static __le32 ext4_dirent_csum(struct inode *inode,
323                                struct ext4_dir_entry *dirent, int size)
324 {
325         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
326         struct ext4_inode_info *ei = EXT4_I(inode);
327         __u32 csum;
328 
329         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
330         return cpu_to_le32(csum);
331 }
332 
333 #define warn_no_space_for_csum(inode)                                   \
334         __warn_no_space_for_csum((inode), __func__, __LINE__)
335 
336 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
337                                      unsigned int line)
338 {
339         __ext4_warning_inode(inode, func, line,
340                 "No space for directory leaf checksum. Please run e2fsck -D.");
341 }
342 
343 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
344 {
345         struct ext4_dir_entry_tail *t;
346 
347         if (!ext4_has_metadata_csum(inode->i_sb))
348                 return 1;
349 
350         t = get_dirent_tail(inode, dirent);
351         if (!t) {
352                 warn_no_space_for_csum(inode);
353                 return 0;
354         }
355 
356         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
357                                                 (void *)t - (void *)dirent))
358                 return 0;
359 
360         return 1;
361 }
362 
363 static void ext4_dirent_csum_set(struct inode *inode,
364                                  struct ext4_dir_entry *dirent)
365 {
366         struct ext4_dir_entry_tail *t;
367 
368         if (!ext4_has_metadata_csum(inode->i_sb))
369                 return;
370 
371         t = get_dirent_tail(inode, dirent);
372         if (!t) {
373                 warn_no_space_for_csum(inode);
374                 return;
375         }
376 
377         t->det_checksum = ext4_dirent_csum(inode, dirent,
378                                            (void *)t - (void *)dirent);
379 }
380 
381 int ext4_handle_dirty_dirent_node(handle_t *handle,
382                                   struct inode *inode,
383                                   struct buffer_head *bh)
384 {
385         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
386         return ext4_handle_dirty_metadata(handle, inode, bh);
387 }
388 
389 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
390                                                struct ext4_dir_entry *dirent,
391                                                int *offset)
392 {
393         struct ext4_dir_entry *dp;
394         struct dx_root_info *root;
395         int count_offset;
396 
397         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
398                 count_offset = 8;
399         else if (le16_to_cpu(dirent->rec_len) == 12) {
400                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
401                 if (le16_to_cpu(dp->rec_len) !=
402                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
403                         return NULL;
404                 root = (struct dx_root_info *)(((void *)dp + 12));
405                 if (root->reserved_zero ||
406                     root->info_length != sizeof(struct dx_root_info))
407                         return NULL;
408                 count_offset = 32;
409         } else
410                 return NULL;
411 
412         if (offset)
413                 *offset = count_offset;
414         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
415 }
416 
417 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
418                            int count_offset, int count, struct dx_tail *t)
419 {
420         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
421         struct ext4_inode_info *ei = EXT4_I(inode);
422         __u32 csum;
423         __le32 save_csum;
424         int size;
425 
426         size = count_offset + (count * sizeof(struct dx_entry));
427         save_csum = t->dt_checksum;
428         t->dt_checksum = 0;
429         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
430         csum = ext4_chksum(sbi, csum, (__u8 *)t, sizeof(struct dx_tail));
431         t->dt_checksum = save_csum;
432 
433         return cpu_to_le32(csum);
434 }
435 
436 static int ext4_dx_csum_verify(struct inode *inode,
437                                struct ext4_dir_entry *dirent)
438 {
439         struct dx_countlimit *c;
440         struct dx_tail *t;
441         int count_offset, limit, count;
442 
443         if (!ext4_has_metadata_csum(inode->i_sb))
444                 return 1;
445 
446         c = get_dx_countlimit(inode, dirent, &count_offset);
447         if (!c) {
448                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
449                 return 1;
450         }
451         limit = le16_to_cpu(c->limit);
452         count = le16_to_cpu(c->count);
453         if (count_offset + (limit * sizeof(struct dx_entry)) >
454             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
455                 warn_no_space_for_csum(inode);
456                 return 1;
457         }
458         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
459 
460         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
461                                             count, t))
462                 return 0;
463         return 1;
464 }
465 
466 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
467 {
468         struct dx_countlimit *c;
469         struct dx_tail *t;
470         int count_offset, limit, count;
471 
472         if (!ext4_has_metadata_csum(inode->i_sb))
473                 return;
474 
475         c = get_dx_countlimit(inode, dirent, &count_offset);
476         if (!c) {
477                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
478                 return;
479         }
480         limit = le16_to_cpu(c->limit);
481         count = le16_to_cpu(c->count);
482         if (count_offset + (limit * sizeof(struct dx_entry)) >
483             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
484                 warn_no_space_for_csum(inode);
485                 return;
486         }
487         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
488 
489         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
490 }
491 
492 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
493                                             struct inode *inode,
494                                             struct buffer_head *bh)
495 {
496         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
497         return ext4_handle_dirty_metadata(handle, inode, bh);
498 }
499 
500 /*
501  * p is at least 6 bytes before the end of page
502  */
503 static inline struct ext4_dir_entry_2 *
504 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
505 {
506         return (struct ext4_dir_entry_2 *)((char *)p +
507                 ext4_rec_len_from_disk(p->rec_len, blocksize));
508 }
509 
510 /*
511  * Future: use high four bits of block for coalesce-on-delete flags
512  * Mask them off for now.
513  */
514 
515 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
516 {
517         return le32_to_cpu(entry->block) & 0x00ffffff;
518 }
519 
520 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
521 {
522         entry->block = cpu_to_le32(value);
523 }
524 
525 static inline unsigned dx_get_hash(struct dx_entry *entry)
526 {
527         return le32_to_cpu(entry->hash);
528 }
529 
530 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
531 {
532         entry->hash = cpu_to_le32(value);
533 }
534 
535 static inline unsigned dx_get_count(struct dx_entry *entries)
536 {
537         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
538 }
539 
540 static inline unsigned dx_get_limit(struct dx_entry *entries)
541 {
542         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
543 }
544 
545 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
546 {
547         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
548 }
549 
550 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
551 {
552         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
553 }
554 
555 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
556 {
557         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
558                 EXT4_DIR_REC_LEN(2) - infosize;
559 
560         if (ext4_has_metadata_csum(dir->i_sb))
561                 entry_space -= sizeof(struct dx_tail);
562         return entry_space / sizeof(struct dx_entry);
563 }
564 
565 static inline unsigned dx_node_limit(struct inode *dir)
566 {
567         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
568 
569         if (ext4_has_metadata_csum(dir->i_sb))
570                 entry_space -= sizeof(struct dx_tail);
571         return entry_space / sizeof(struct dx_entry);
572 }
573 
574 /*
575  * Debug
576  */
577 #ifdef DX_DEBUG
578 static void dx_show_index(char * label, struct dx_entry *entries)
579 {
580         int i, n = dx_get_count (entries);
581         printk(KERN_DEBUG "%s index ", label);
582         for (i = 0; i < n; i++) {
583                 printk("%x->%lu ", i ? dx_get_hash(entries + i) :
584                                 0, (unsigned long)dx_get_block(entries + i));
585         }
586         printk("\n");
587 }
588 
589 struct stats
590 {
591         unsigned names;
592         unsigned space;
593         unsigned bcount;
594 };
595 
596 static struct stats dx_show_leaf(struct inode *dir,
597                                 struct dx_hash_info *hinfo,
598                                 struct ext4_dir_entry_2 *de,
599                                 int size, int show_names)
600 {
601         unsigned names = 0, space = 0;
602         char *base = (char *) de;
603         struct dx_hash_info h = *hinfo;
604 
605         printk("names: ");
606         while ((char *) de < base + size)
607         {
608                 if (de->inode)
609                 {
610                         if (show_names)
611                         {
612 #ifdef CONFIG_EXT4_FS_ENCRYPTION
613                                 int len;
614                                 char *name;
615                                 struct ext4_str fname_crypto_str
616                                         = {.name = NULL, .len = 0};
617                                 int res = 0;
618 
619                                 name  = de->name;
620                                 len = de->name_len;
621                                 if (ext4_encrypted_inode(inode))
622                                         res = ext4_get_encryption_info(dir);
623                                 if (res) {
624                                         printk(KERN_WARNING "Error setting up"
625                                                " fname crypto: %d\n", res);
626                                 }
627                                 if (ctx == NULL) {
628                                         /* Directory is not encrypted */
629                                         ext4fs_dirhash(de->name,
630                                                 de->name_len, &h);
631                                         printk("%*.s:(U)%x.%u ", len,
632                                                name, h.hash,
633                                                (unsigned) ((char *) de
634                                                            - base));
635                                 } else {
636                                         /* Directory is encrypted */
637                                         res = ext4_fname_crypto_alloc_buffer(
638                                                 ctx, de->name_len,
639                                                 &fname_crypto_str);
640                                         if (res < 0) {
641                                                 printk(KERN_WARNING "Error "
642                                                         "allocating crypto "
643                                                         "buffer--skipping "
644                                                         "crypto\n");
645                                                 ctx = NULL;
646                                         }
647                                         res = ext4_fname_disk_to_usr(ctx, NULL, de,
648                                                         &fname_crypto_str);
649                                         if (res < 0) {
650                                                 printk(KERN_WARNING "Error "
651                                                         "converting filename "
652                                                         "from disk to usr"
653                                                         "\n");
654                                                 name = "??";
655                                                 len = 2;
656                                         } else {
657                                                 name = fname_crypto_str.name;
658                                                 len = fname_crypto_str.len;
659                                         }
660                                         ext4fs_dirhash(de->name, de->name_len,
661                                                        &h);
662                                         printk("%*.s:(E)%x.%u ", len, name,
663                                                h.hash, (unsigned) ((char *) de
664                                                                    - base));
665                                         ext4_fname_crypto_free_buffer(
666                                                 &fname_crypto_str);
667                                 }
668 #else
669                                 int len = de->name_len;
670                                 char *name = de->name;
671                                 ext4fs_dirhash(de->name, de->name_len, &h);
672                                 printk("%*.s:%x.%u ", len, name, h.hash,
673                                        (unsigned) ((char *) de - base));
674 #endif
675                         }
676                         space += EXT4_DIR_REC_LEN(de->name_len);
677                         names++;
678                 }
679                 de = ext4_next_entry(de, size);
680         }
681         printk("(%i)\n", names);
682         return (struct stats) { names, space, 1 };
683 }
684 
685 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
686                              struct dx_entry *entries, int levels)
687 {
688         unsigned blocksize = dir->i_sb->s_blocksize;
689         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
690         unsigned bcount = 0;
691         struct buffer_head *bh;
692         printk("%i indexed blocks...\n", count);
693         for (i = 0; i < count; i++, entries++)
694         {
695                 ext4_lblk_t block = dx_get_block(entries);
696                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
697                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
698                 struct stats stats;
699                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
700                 bh = ext4_bread(NULL,dir, block, 0);
701                 if (!bh || IS_ERR(bh))
702                         continue;
703                 stats = levels?
704                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
705                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
706                         bh->b_data, blocksize, 0);
707                 names += stats.names;
708                 space += stats.space;
709                 bcount += stats.bcount;
710                 brelse(bh);
711         }
712         if (bcount)
713                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
714                        levels ? "" : "   ", names, space/bcount,
715                        (space/bcount)*100/blocksize);
716         return (struct stats) { names, space, bcount};
717 }
718 #endif /* DX_DEBUG */
719 
720 /*
721  * Probe for a directory leaf block to search.
722  *
723  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
724  * error in the directory index, and the caller should fall back to
725  * searching the directory normally.  The callers of dx_probe **MUST**
726  * check for this error code, and make sure it never gets reflected
727  * back to userspace.
728  */
729 static struct dx_frame *
730 dx_probe(struct ext4_filename *fname, struct inode *dir,
731          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
732 {
733         unsigned count, indirect;
734         struct dx_entry *at, *entries, *p, *q, *m;
735         struct dx_root *root;
736         struct dx_frame *frame = frame_in;
737         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
738         u32 hash;
739 
740         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
741         if (IS_ERR(frame->bh))
742                 return (struct dx_frame *) frame->bh;
743 
744         root = (struct dx_root *) frame->bh->b_data;
745         if (root->info.hash_version != DX_HASH_TEA &&
746             root->info.hash_version != DX_HASH_HALF_MD4 &&
747             root->info.hash_version != DX_HASH_LEGACY) {
748                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
749                                    root->info.hash_version);
750                 goto fail;
751         }
752         if (fname)
753                 hinfo = &fname->hinfo;
754         hinfo->hash_version = root->info.hash_version;
755         if (hinfo->hash_version <= DX_HASH_TEA)
756                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
757         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
758         if (fname && fname_name(fname))
759                 ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
760         hash = hinfo->hash;
761 
762         if (root->info.unused_flags & 1) {
763                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
764                                    root->info.unused_flags);
765                 goto fail;
766         }
767 
768         indirect = root->info.indirect_levels;
769         if (indirect > 1) {
770                 ext4_warning_inode(dir, "Unimplemented hash depth: %#06x",
771                                    root->info.indirect_levels);
772                 goto fail;
773         }
774 
775         entries = (struct dx_entry *)(((char *)&root->info) +
776                                       root->info.info_length);
777 
778         if (dx_get_limit(entries) != dx_root_limit(dir,
779                                                    root->info.info_length)) {
780                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
781                                    dx_get_limit(entries),
782                                    dx_root_limit(dir, root->info.info_length));
783                 goto fail;
784         }
785 
786         dxtrace(printk("Look up %x", hash));
787         while (1) {
788                 count = dx_get_count(entries);
789                 if (!count || count > dx_get_limit(entries)) {
790                         ext4_warning_inode(dir,
791                                            "dx entry: count %u beyond limit %u",
792                                            count, dx_get_limit(entries));
793                         goto fail;
794                 }
795 
796                 p = entries + 1;
797                 q = entries + count - 1;
798                 while (p <= q) {
799                         m = p + (q - p) / 2;
800                         dxtrace(printk("."));
801                         if (dx_get_hash(m) > hash)
802                                 q = m - 1;
803                         else
804                                 p = m + 1;
805                 }
806 
807                 if (0) { // linear search cross check
808                         unsigned n = count - 1;
809                         at = entries;
810                         while (n--)
811                         {
812                                 dxtrace(printk(","));
813                                 if (dx_get_hash(++at) > hash)
814                                 {
815                                         at--;
816                                         break;
817                                 }
818                         }
819                         assert (at == p - 1);
820                 }
821 
822                 at = p - 1;
823                 dxtrace(printk(" %x->%u\n", at == entries ? 0 : dx_get_hash(at),
824                                dx_get_block(at)));
825                 frame->entries = entries;
826                 frame->at = at;
827                 if (!indirect--)
828                         return frame;
829                 frame++;
830                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
831                 if (IS_ERR(frame->bh)) {
832                         ret_err = (struct dx_frame *) frame->bh;
833                         frame->bh = NULL;
834                         goto fail;
835                 }
836                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
837 
838                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
839                         ext4_warning_inode(dir,
840                                 "dx entry: limit %u != node limit %u",
841                                 dx_get_limit(entries), dx_node_limit(dir));
842                         goto fail;
843                 }
844         }
845 fail:
846         while (frame >= frame_in) {
847                 brelse(frame->bh);
848                 frame--;
849         }
850 
851         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
852                 ext4_warning_inode(dir,
853                         "Corrupt directory, running e2fsck is recommended");
854         return ret_err;
855 }
856 
857 static void dx_release(struct dx_frame *frames)
858 {
859         if (frames[0].bh == NULL)
860                 return;
861 
862         if (((struct dx_root *)frames[0].bh->b_data)->info.indirect_levels)
863                 brelse(frames[1].bh);
864         brelse(frames[0].bh);
865 }
866 
867 /*
868  * This function increments the frame pointer to search the next leaf
869  * block, and reads in the necessary intervening nodes if the search
870  * should be necessary.  Whether or not the search is necessary is
871  * controlled by the hash parameter.  If the hash value is even, then
872  * the search is only continued if the next block starts with that
873  * hash value.  This is used if we are searching for a specific file.
874  *
875  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
876  *
877  * This function returns 1 if the caller should continue to search,
878  * or 0 if it should not.  If there is an error reading one of the
879  * index blocks, it will a negative error code.
880  *
881  * If start_hash is non-null, it will be filled in with the starting
882  * hash of the next page.
883  */
884 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
885                                  struct dx_frame *frame,
886                                  struct dx_frame *frames,
887                                  __u32 *start_hash)
888 {
889         struct dx_frame *p;
890         struct buffer_head *bh;
891         int num_frames = 0;
892         __u32 bhash;
893 
894         p = frame;
895         /*
896          * Find the next leaf page by incrementing the frame pointer.
897          * If we run out of entries in the interior node, loop around and
898          * increment pointer in the parent node.  When we break out of
899          * this loop, num_frames indicates the number of interior
900          * nodes need to be read.
901          */
902         while (1) {
903                 if (++(p->at) < p->entries + dx_get_count(p->entries))
904                         break;
905                 if (p == frames)
906                         return 0;
907                 num_frames++;
908                 p--;
909         }
910 
911         /*
912          * If the hash is 1, then continue only if the next page has a
913          * continuation hash of any value.  This is used for readdir
914          * handling.  Otherwise, check to see if the hash matches the
915          * desired contiuation hash.  If it doesn't, return since
916          * there's no point to read in the successive index pages.
917          */
918         bhash = dx_get_hash(p->at);
919         if (start_hash)
920                 *start_hash = bhash;
921         if ((hash & 1) == 0) {
922                 if ((bhash & ~1) != hash)
923                         return 0;
924         }
925         /*
926          * If the hash is HASH_NB_ALWAYS, we always go to the next
927          * block so no check is necessary
928          */
929         while (num_frames--) {
930                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
931                 if (IS_ERR(bh))
932                         return PTR_ERR(bh);
933                 p++;
934                 brelse(p->bh);
935                 p->bh = bh;
936                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
937         }
938         return 1;
939 }
940 
941 
942 /*
943  * This function fills a red-black tree with information from a
944  * directory block.  It returns the number directory entries loaded
945  * into the tree.  If there is an error it is returned in err.
946  */
947 static int htree_dirblock_to_tree(struct file *dir_file,
948                                   struct inode *dir, ext4_lblk_t block,
949                                   struct dx_hash_info *hinfo,
950                                   __u32 start_hash, __u32 start_minor_hash)
951 {
952         struct buffer_head *bh;
953         struct ext4_dir_entry_2 *de, *top;
954         int err = 0, count = 0;
955         struct ext4_str fname_crypto_str = {.name = NULL, .len = 0}, tmp_str;
956 
957         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
958                                                         (unsigned long)block));
959         bh = ext4_read_dirblock(dir, block, DIRENT);
960         if (IS_ERR(bh))
961                 return PTR_ERR(bh);
962 
963         de = (struct ext4_dir_entry_2 *) bh->b_data;
964         top = (struct ext4_dir_entry_2 *) ((char *) de +
965                                            dir->i_sb->s_blocksize -
966                                            EXT4_DIR_REC_LEN(0));
967 #ifdef CONFIG_EXT4_FS_ENCRYPTION
968         /* Check if the directory is encrypted */
969         if (ext4_encrypted_inode(dir)) {
970                 err = ext4_get_encryption_info(dir);
971                 if (err < 0) {
972                         brelse(bh);
973                         return err;
974                 }
975                 err = ext4_fname_crypto_alloc_buffer(dir, EXT4_NAME_LEN,
976                                                      &fname_crypto_str);
977                 if (err < 0) {
978                         brelse(bh);
979                         return err;
980                 }
981         }
982 #endif
983         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
984                 if (ext4_check_dir_entry(dir, NULL, de, bh,
985                                 bh->b_data, bh->b_size,
986                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
987                                          + ((char *)de - bh->b_data))) {
988                         /* silently ignore the rest of the block */
989                         break;
990                 }
991                 ext4fs_dirhash(de->name, de->name_len, hinfo);
992                 if ((hinfo->hash < start_hash) ||
993                     ((hinfo->hash == start_hash) &&
994                      (hinfo->minor_hash < start_minor_hash)))
995                         continue;
996                 if (de->inode == 0)
997                         continue;
998                 if (!ext4_encrypted_inode(dir)) {
999                         tmp_str.name = de->name;
1000                         tmp_str.len = de->name_len;
1001                         err = ext4_htree_store_dirent(dir_file,
1002                                    hinfo->hash, hinfo->minor_hash, de,
1003                                    &tmp_str);
1004                 } else {
1005                         int save_len = fname_crypto_str.len;
1006 
1007                         /* Directory is encrypted */
1008                         err = ext4_fname_disk_to_usr(dir, hinfo, de,
1009                                                      &fname_crypto_str);
1010                         if (err < 0) {
1011                                 count = err;
1012                                 goto errout;
1013                         }
1014                         err = ext4_htree_store_dirent(dir_file,
1015                                    hinfo->hash, hinfo->minor_hash, de,
1016                                         &fname_crypto_str);
1017                         fname_crypto_str.len = save_len;
1018                 }
1019                 if (err != 0) {
1020                         count = err;
1021                         goto errout;
1022                 }
1023                 count++;
1024         }
1025 errout:
1026         brelse(bh);
1027 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1028         ext4_fname_crypto_free_buffer(&fname_crypto_str);
1029 #endif
1030         return count;
1031 }
1032 
1033 
1034 /*
1035  * This function fills a red-black tree with information from a
1036  * directory.  We start scanning the directory in hash order, starting
1037  * at start_hash and start_minor_hash.
1038  *
1039  * This function returns the number of entries inserted into the tree,
1040  * or a negative error code.
1041  */
1042 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1043                          __u32 start_minor_hash, __u32 *next_hash)
1044 {
1045         struct dx_hash_info hinfo;
1046         struct ext4_dir_entry_2 *de;
1047         struct dx_frame frames[2], *frame;
1048         struct inode *dir;
1049         ext4_lblk_t block;
1050         int count = 0;
1051         int ret, err;
1052         __u32 hashval;
1053         struct ext4_str tmp_str;
1054 
1055         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1056                        start_hash, start_minor_hash));
1057         dir = file_inode(dir_file);
1058         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1059                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1060                 if (hinfo.hash_version <= DX_HASH_TEA)
1061                         hinfo.hash_version +=
1062                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1063                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1064                 if (ext4_has_inline_data(dir)) {
1065                         int has_inline_data = 1;
1066                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
1067                                                         &hinfo, start_hash,
1068                                                         start_minor_hash,
1069                                                         &has_inline_data);
1070                         if (has_inline_data) {
1071                                 *next_hash = ~0;
1072                                 return count;
1073                         }
1074                 }
1075                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1076                                                start_hash, start_minor_hash);
1077                 *next_hash = ~0;
1078                 return count;
1079         }
1080         hinfo.hash = start_hash;
1081         hinfo.minor_hash = 0;
1082         frame = dx_probe(NULL, dir, &hinfo, frames);
1083         if (IS_ERR(frame))
1084                 return PTR_ERR(frame);
1085 
1086         /* Add '.' and '..' from the htree header */
1087         if (!start_hash && !start_minor_hash) {
1088                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1089                 tmp_str.name = de->name;
1090                 tmp_str.len = de->name_len;
1091                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1092                                               de, &tmp_str);
1093                 if (err != 0)
1094                         goto errout;
1095                 count++;
1096         }
1097         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1098                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1099                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1100                 tmp_str.name = de->name;
1101                 tmp_str.len = de->name_len;
1102                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1103                                               de, &tmp_str);
1104                 if (err != 0)
1105                         goto errout;
1106                 count++;
1107         }
1108 
1109         while (1) {
1110                 block = dx_get_block(frame->at);
1111                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1112                                              start_hash, start_minor_hash);
1113                 if (ret < 0) {
1114                         err = ret;
1115                         goto errout;
1116                 }
1117                 count += ret;
1118                 hashval = ~0;
1119                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1120                                             frame, frames, &hashval);
1121                 *next_hash = hashval;
1122                 if (ret < 0) {
1123                         err = ret;
1124                         goto errout;
1125                 }
1126                 /*
1127                  * Stop if:  (a) there are no more entries, or
1128                  * (b) we have inserted at least one entry and the
1129                  * next hash value is not a continuation
1130                  */
1131                 if ((ret == 0) ||
1132                     (count && ((hashval & 1) == 0)))
1133                         break;
1134         }
1135         dx_release(frames);
1136         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1137                        "next hash: %x\n", count, *next_hash));
1138         return count;
1139 errout:
1140         dx_release(frames);
1141         return (err);
1142 }
1143 
1144 static inline int search_dirblock(struct buffer_head *bh,
1145                                   struct inode *dir,
1146                                   struct ext4_filename *fname,
1147                                   const struct qstr *d_name,
1148                                   unsigned int offset,
1149                                   struct ext4_dir_entry_2 **res_dir)
1150 {
1151         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1152                                fname, d_name, offset, res_dir);
1153 }
1154 
1155 /*
1156  * Directory block splitting, compacting
1157  */
1158 
1159 /*
1160  * Create map of hash values, offsets, and sizes, stored at end of block.
1161  * Returns number of entries mapped.
1162  */
1163 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
1164                        unsigned blocksize, struct dx_hash_info *hinfo,
1165                        struct dx_map_entry *map_tail)
1166 {
1167         int count = 0;
1168         char *base = (char *) de;
1169         struct dx_hash_info h = *hinfo;
1170 
1171         while ((char *) de < base + blocksize) {
1172                 if (de->name_len && de->inode) {
1173                         ext4fs_dirhash(de->name, de->name_len, &h);
1174                         map_tail--;
1175                         map_tail->hash = h.hash;
1176                         map_tail->offs = ((char *) de - base)>>2;
1177                         map_tail->size = le16_to_cpu(de->rec_len);
1178                         count++;
1179                         cond_resched();
1180                 }
1181                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1182                 de = ext4_next_entry(de, blocksize);
1183         }
1184         return count;
1185 }
1186 
1187 /* Sort map by hash value */
1188 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1189 {
1190         struct dx_map_entry *p, *q, *top = map + count - 1;
1191         int more;
1192         /* Combsort until bubble sort doesn't suck */
1193         while (count > 2) {
1194                 count = count*10/13;
1195                 if (count - 9 < 2) /* 9, 10 -> 11 */
1196                         count = 11;
1197                 for (p = top, q = p - count; q >= map; p--, q--)
1198                         if (p->hash < q->hash)
1199                                 swap(*p, *q);
1200         }
1201         /* Garden variety bubble sort */
1202         do {
1203                 more = 0;
1204                 q = top;
1205                 while (q-- > map) {
1206                         if (q[1].hash >= q[0].hash)
1207                                 continue;
1208                         swap(*(q+1), *q);
1209                         more = 1;
1210                 }
1211         } while(more);
1212 }
1213 
1214 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1215 {
1216         struct dx_entry *entries = frame->entries;
1217         struct dx_entry *old = frame->at, *new = old + 1;
1218         int count = dx_get_count(entries);
1219 
1220         assert(count < dx_get_limit(entries));
1221         assert(old < entries + count);
1222         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1223         dx_set_hash(new, hash);
1224         dx_set_block(new, block);
1225         dx_set_count(entries, count + 1);
1226 }
1227 
1228 /*
1229  * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.
1230  *
1231  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
1232  * `de != NULL' is guaranteed by caller.
1233  */
1234 static inline int ext4_match(struct ext4_filename *fname,
1235                              struct ext4_dir_entry_2 *de)
1236 {
1237         const void *name = fname_name(fname);
1238         u32 len = fname_len(fname);
1239 
1240         if (!de->inode)
1241                 return 0;
1242 
1243 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1244         if (unlikely(!name)) {
1245                 if (fname->usr_fname->name[0] == '_') {
1246                         int ret;
1247                         if (de->name_len < 16)
1248                                 return 0;
1249                         ret = memcmp(de->name + de->name_len - 16,
1250                                      fname->crypto_buf.name + 8, 16);
1251                         return (ret == 0) ? 1 : 0;
1252                 }
1253                 name = fname->crypto_buf.name;
1254                 len = fname->crypto_buf.len;
1255         }
1256 #endif
1257         if (de->name_len != len)
1258                 return 0;
1259         return (memcmp(de->name, name, len) == 0) ? 1 : 0;
1260 }
1261 
1262 /*
1263  * Returns 0 if not found, -1 on failure, and 1 on success
1264  */
1265 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1266                     struct inode *dir, struct ext4_filename *fname,
1267                     const struct qstr *d_name,
1268                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1269 {
1270         struct ext4_dir_entry_2 * de;
1271         char * dlimit;
1272         int de_len;
1273         int res;
1274 
1275         de = (struct ext4_dir_entry_2 *)search_buf;
1276         dlimit = search_buf + buf_size;
1277         while ((char *) de < dlimit) {
1278                 /* this code is executed quadratically often */
1279                 /* do minimal checking `by hand' */
1280                 if ((char *) de + de->name_len <= dlimit) {
1281                         res = ext4_match(fname, de);
1282                         if (res < 0) {
1283                                 res = -1;
1284                                 goto return_result;
1285                         }
1286                         if (res > 0) {
1287                                 /* found a match - just to be sure, do
1288                                  * a full check */
1289                                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1290                                                 bh->b_data,
1291                                                  bh->b_size, offset)) {
1292                                         res = -1;
1293                                         goto return_result;
1294                                 }
1295                                 *res_dir = de;
1296                                 res = 1;
1297                                 goto return_result;
1298                         }
1299 
1300                 }
1301                 /* prevent looping on a bad block */
1302                 de_len = ext4_rec_len_from_disk(de->rec_len,
1303                                                 dir->i_sb->s_blocksize);
1304                 if (de_len <= 0) {
1305                         res = -1;
1306                         goto return_result;
1307                 }
1308                 offset += de_len;
1309                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1310         }
1311 
1312         res = 0;
1313 return_result:
1314         return res;
1315 }
1316 
1317 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1318                                struct ext4_dir_entry *de)
1319 {
1320         struct super_block *sb = dir->i_sb;
1321 
1322         if (!is_dx(dir))
1323                 return 0;
1324         if (block == 0)
1325                 return 1;
1326         if (de->inode == 0 &&
1327             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1328                         sb->s_blocksize)
1329                 return 1;
1330         return 0;
1331 }
1332 
1333 /*
1334  *      ext4_find_entry()
1335  *
1336  * finds an entry in the specified directory with the wanted name. It
1337  * returns the cache buffer in which the entry was found, and the entry
1338  * itself (as a parameter - res_dir). It does NOT read the inode of the
1339  * entry - you'll have to do that yourself if you want to.
1340  *
1341  * The returned buffer_head has ->b_count elevated.  The caller is expected
1342  * to brelse() it when appropriate.
1343  */
1344 static struct buffer_head * ext4_find_entry (struct inode *dir,
1345                                         const struct qstr *d_name,
1346                                         struct ext4_dir_entry_2 **res_dir,
1347                                         int *inlined)
1348 {
1349         struct super_block *sb;
1350         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1351         struct buffer_head *bh, *ret = NULL;
1352         ext4_lblk_t start, block, b;
1353         const u8 *name = d_name->name;
1354         int ra_max = 0;         /* Number of bh's in the readahead
1355                                    buffer, bh_use[] */
1356         int ra_ptr = 0;         /* Current index into readahead
1357                                    buffer */
1358         int num = 0;
1359         ext4_lblk_t  nblocks;
1360         int i, namelen, retval;
1361         struct ext4_filename fname;
1362 
1363         *res_dir = NULL;
1364         sb = dir->i_sb;
1365         namelen = d_name->len;
1366         if (namelen > EXT4_NAME_LEN)
1367                 return NULL;
1368 
1369         retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1370         if (retval)
1371                 return ERR_PTR(retval);
1372 
1373         if (ext4_has_inline_data(dir)) {
1374                 int has_inline_data = 1;
1375                 ret = ext4_find_inline_entry(dir, &fname, d_name, res_dir,
1376                                              &has_inline_data);
1377                 if (has_inline_data) {
1378                         if (inlined)
1379                                 *inlined = 1;
1380                         goto cleanup_and_exit;
1381                 }
1382         }
1383 
1384         if ((namelen <= 2) && (name[0] == '.') &&
1385             (name[1] == '.' || name[1] == '\0')) {
1386                 /*
1387                  * "." or ".." will only be in the first block
1388                  * NFS may look up ".."; "." should be handled by the VFS
1389                  */
1390                 block = start = 0;
1391                 nblocks = 1;
1392                 goto restart;
1393         }
1394         if (is_dx(dir)) {
1395                 ret = ext4_dx_find_entry(dir, &fname, res_dir);
1396                 /*
1397                  * On success, or if the error was file not found,
1398                  * return.  Otherwise, fall back to doing a search the
1399                  * old fashioned way.
1400                  */
1401                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1402                         goto cleanup_and_exit;
1403                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1404                                "falling back\n"));
1405         }
1406         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1407         start = EXT4_I(dir)->i_dir_start_lookup;
1408         if (start >= nblocks)
1409                 start = 0;
1410         block = start;
1411 restart:
1412         do {
1413                 /*
1414                  * We deal with the read-ahead logic here.
1415                  */
1416                 if (ra_ptr >= ra_max) {
1417                         /* Refill the readahead buffer */
1418                         ra_ptr = 0;
1419                         b = block;
1420                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
1421                                 /*
1422                                  * Terminate if we reach the end of the
1423                                  * directory and must wrap, or if our
1424                                  * search has finished at this block.
1425                                  */
1426                                 if (b >= nblocks || (num && block == start)) {
1427                                         bh_use[ra_max] = NULL;
1428                                         break;
1429                                 }
1430                                 num++;
1431                                 bh = ext4_getblk(NULL, dir, b++, 0);
1432                                 if (unlikely(IS_ERR(bh))) {
1433                                         if (ra_max == 0) {
1434                                                 ret = bh;
1435                                                 goto cleanup_and_exit;
1436                                         }
1437                                         break;
1438                                 }
1439                                 bh_use[ra_max] = bh;
1440                                 if (bh)
1441                                         ll_rw_block(READ | REQ_META | REQ_PRIO,
1442                                                     1, &bh);
1443                         }
1444                 }
1445                 if ((bh = bh_use[ra_ptr++]) == NULL)
1446                         goto next;
1447                 wait_on_buffer(bh);
1448                 if (!buffer_uptodate(bh)) {
1449                         /* read error, skip block & hope for the best */
1450                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1451                                          (unsigned long) block);
1452                         brelse(bh);
1453                         goto next;
1454                 }
1455                 if (!buffer_verified(bh) &&
1456                     !is_dx_internal_node(dir, block,
1457                                          (struct ext4_dir_entry *)bh->b_data) &&
1458                     !ext4_dirent_csum_verify(dir,
1459                                 (struct ext4_dir_entry *)bh->b_data)) {
1460                         EXT4_ERROR_INODE(dir, "checksumming directory "
1461                                          "block %lu", (unsigned long)block);
1462                         brelse(bh);
1463                         goto next;
1464                 }
1465                 set_buffer_verified(bh);
1466                 i = search_dirblock(bh, dir, &fname, d_name,
1467                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1468                 if (i == 1) {
1469                         EXT4_I(dir)->i_dir_start_lookup = block;
1470                         ret = bh;
1471                         goto cleanup_and_exit;
1472                 } else {
1473                         brelse(bh);
1474                         if (i < 0)
1475                                 goto cleanup_and_exit;
1476                 }
1477         next:
1478                 if (++block >= nblocks)
1479                         block = 0;
1480         } while (block != start);
1481 
1482         /*
1483          * If the directory has grown while we were searching, then
1484          * search the last part of the directory before giving up.
1485          */
1486         block = nblocks;
1487         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1488         if (block < nblocks) {
1489                 start = 0;
1490                 goto restart;
1491         }
1492 
1493 cleanup_and_exit:
1494         /* Clean up the read-ahead blocks */
1495         for (; ra_ptr < ra_max; ra_ptr++)
1496                 brelse(bh_use[ra_ptr]);
1497         ext4_fname_free_filename(&fname);
1498         return ret;
1499 }
1500 
1501 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1502                         struct ext4_filename *fname,
1503                         struct ext4_dir_entry_2 **res_dir)
1504 {
1505         struct super_block * sb = dir->i_sb;
1506         struct dx_frame frames[2], *frame;
1507         const struct qstr *d_name = fname->usr_fname;
1508         struct buffer_head *bh;
1509         ext4_lblk_t block;
1510         int retval;
1511 
1512 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1513         *res_dir = NULL;
1514 #endif
1515         frame = dx_probe(fname, dir, NULL, frames);
1516         if (IS_ERR(frame))
1517                 return (struct buffer_head *) frame;
1518         do {
1519                 block = dx_get_block(frame->at);
1520                 bh = ext4_read_dirblock(dir, block, DIRENT);
1521                 if (IS_ERR(bh))
1522                         goto errout;
1523 
1524                 retval = search_dirblock(bh, dir, fname, d_name,
1525                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1526                                          res_dir);
1527                 if (retval == 1)
1528                         goto success;
1529                 brelse(bh);
1530                 if (retval == -1) {
1531                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1532                         goto errout;
1533                 }
1534 
1535                 /* Check to see if we should continue to search */
1536                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1537                                                frames, NULL);
1538                 if (retval < 0) {
1539                         ext4_warning_inode(dir,
1540                                 "error %d reading directory index block",
1541                                 retval);
1542                         bh = ERR_PTR(retval);
1543                         goto errout;
1544                 }
1545         } while (retval == 1);
1546 
1547         bh = NULL;
1548 errout:
1549         dxtrace(printk(KERN_DEBUG "%s not found\n", d_name->name));
1550 success:
1551         dx_release(frames);
1552         return bh;
1553 }
1554 
1555 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1556 {
1557         struct inode *inode;
1558         struct ext4_dir_entry_2 *de;
1559         struct buffer_head *bh;
1560 
1561         if (dentry->d_name.len > EXT4_NAME_LEN)
1562                 return ERR_PTR(-ENAMETOOLONG);
1563 
1564         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1565         if (IS_ERR(bh))
1566                 return (struct dentry *) bh;
1567         inode = NULL;
1568         if (bh) {
1569                 __u32 ino = le32_to_cpu(de->inode);
1570                 brelse(bh);
1571                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1572                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1573                         return ERR_PTR(-EIO);
1574                 }
1575                 if (unlikely(ino == dir->i_ino)) {
1576                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1577                                          dentry);
1578                         return ERR_PTR(-EIO);
1579                 }
1580                 inode = ext4_iget_normal(dir->i_sb, ino);
1581                 if (inode == ERR_PTR(-ESTALE)) {
1582                         EXT4_ERROR_INODE(dir,
1583                                          "deleted inode referenced: %u",
1584                                          ino);
1585                         return ERR_PTR(-EIO);
1586                 }
1587                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1588                     (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1589                      S_ISLNK(inode->i_mode)) &&
1590                     !ext4_is_child_context_consistent_with_parent(dir,
1591                                                                   inode)) {
1592                         iput(inode);
1593                         ext4_warning(inode->i_sb,
1594                                      "Inconsistent encryption contexts: %lu/%lu\n",
1595                                      (unsigned long) dir->i_ino,
1596                                      (unsigned long) inode->i_ino);
1597                         return ERR_PTR(-EPERM);
1598                 }
1599         }
1600         return d_splice_alias(inode, dentry);
1601 }
1602 
1603 
1604 struct dentry *ext4_get_parent(struct dentry *child)
1605 {
1606         __u32 ino;
1607         static const struct qstr dotdot = QSTR_INIT("..", 2);
1608         struct ext4_dir_entry_2 * de;
1609         struct buffer_head *bh;
1610 
1611         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1612         if (IS_ERR(bh))
1613                 return (struct dentry *) bh;
1614         if (!bh)
1615                 return ERR_PTR(-ENOENT);
1616         ino = le32_to_cpu(de->inode);
1617         brelse(bh);
1618 
1619         if (!ext4_valid_inum(d_inode(child)->i_sb, ino)) {
1620                 EXT4_ERROR_INODE(d_inode(child),
1621                                  "bad parent inode number: %u", ino);
1622                 return ERR_PTR(-EIO);
1623         }
1624 
1625         return d_obtain_alias(ext4_iget_normal(d_inode(child)->i_sb, ino));
1626 }
1627 
1628 /*
1629  * Move count entries from end of map between two memory locations.
1630  * Returns pointer to last entry moved.
1631  */
1632 static struct ext4_dir_entry_2 *
1633 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1634                 unsigned blocksize)
1635 {
1636         unsigned rec_len = 0;
1637 
1638         while (count--) {
1639                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1640                                                 (from + (map->offs<<2));
1641                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1642                 memcpy (to, de, rec_len);
1643                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1644                                 ext4_rec_len_to_disk(rec_len, blocksize);
1645                 de->inode = 0;
1646                 map++;
1647                 to += rec_len;
1648         }
1649         return (struct ext4_dir_entry_2 *) (to - rec_len);
1650 }
1651 
1652 /*
1653  * Compact each dir entry in the range to the minimal rec_len.
1654  * Returns pointer to last entry in range.
1655  */
1656 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1657 {
1658         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1659         unsigned rec_len = 0;
1660 
1661         prev = to = de;
1662         while ((char*)de < base + blocksize) {
1663                 next = ext4_next_entry(de, blocksize);
1664                 if (de->inode && de->name_len) {
1665                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1666                         if (de > to)
1667                                 memmove(to, de, rec_len);
1668                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1669                         prev = to;
1670                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1671                 }
1672                 de = next;
1673         }
1674         return prev;
1675 }
1676 
1677 /*
1678  * Split a full leaf block to make room for a new dir entry.
1679  * Allocate a new block, and move entries so that they are approx. equally full.
1680  * Returns pointer to de in block into which the new entry will be inserted.
1681  */
1682 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1683                         struct buffer_head **bh,struct dx_frame *frame,
1684                         struct dx_hash_info *hinfo)
1685 {
1686         unsigned blocksize = dir->i_sb->s_blocksize;
1687         unsigned count, continued;
1688         struct buffer_head *bh2;
1689         ext4_lblk_t newblock;
1690         u32 hash2;
1691         struct dx_map_entry *map;
1692         char *data1 = (*bh)->b_data, *data2;
1693         unsigned split, move, size;
1694         struct ext4_dir_entry_2 *de = NULL, *de2;
1695         struct ext4_dir_entry_tail *t;
1696         int     csum_size = 0;
1697         int     err = 0, i;
1698 
1699         if (ext4_has_metadata_csum(dir->i_sb))
1700                 csum_size = sizeof(struct ext4_dir_entry_tail);
1701 
1702         bh2 = ext4_append(handle, dir, &newblock);
1703         if (IS_ERR(bh2)) {
1704                 brelse(*bh);
1705                 *bh = NULL;
1706                 return (struct ext4_dir_entry_2 *) bh2;
1707         }
1708 
1709         BUFFER_TRACE(*bh, "get_write_access");
1710         err = ext4_journal_get_write_access(handle, *bh);
1711         if (err)
1712                 goto journal_error;
1713 
1714         BUFFER_TRACE(frame->bh, "get_write_access");
1715         err = ext4_journal_get_write_access(handle, frame->bh);
1716         if (err)
1717                 goto journal_error;
1718 
1719         data2 = bh2->b_data;
1720 
1721         /* create map in the end of data2 block */
1722         map = (struct dx_map_entry *) (data2 + blocksize);
1723         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1724                              blocksize, hinfo, map);
1725         map -= count;
1726         dx_sort_map(map, count);
1727         /* Split the existing block in the middle, size-wise */
1728         size = 0;
1729         move = 0;
1730         for (i = count-1; i >= 0; i--) {
1731                 /* is more than half of this entry in 2nd half of the block? */
1732                 if (size + map[i].size/2 > blocksize/2)
1733                         break;
1734                 size += map[i].size;
1735                 move++;
1736         }
1737         /* map index at which we will split */
1738         split = count - move;
1739         hash2 = map[split].hash;
1740         continued = hash2 == map[split - 1].hash;
1741         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1742                         (unsigned long)dx_get_block(frame->at),
1743                                         hash2, split, count-split));
1744 
1745         /* Fancy dance to stay within two buffers */
1746         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1747                               blocksize);
1748         de = dx_pack_dirents(data1, blocksize);
1749         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1750                                            (char *) de,
1751                                            blocksize);
1752         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1753                                             (char *) de2,
1754                                             blocksize);
1755         if (csum_size) {
1756                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1757                 initialize_dirent_tail(t, blocksize);
1758 
1759                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1760                 initialize_dirent_tail(t, blocksize);
1761         }
1762 
1763         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1764                         blocksize, 1));
1765         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1766                         blocksize, 1));
1767 
1768         /* Which block gets the new entry? */
1769         if (hinfo->hash >= hash2) {
1770                 swap(*bh, bh2);
1771                 de = de2;
1772         }
1773         dx_insert_block(frame, hash2 + continued, newblock);
1774         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1775         if (err)
1776                 goto journal_error;
1777         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1778         if (err)
1779                 goto journal_error;
1780         brelse(bh2);
1781         dxtrace(dx_show_index("frame", frame->entries));
1782         return de;
1783 
1784 journal_error:
1785         brelse(*bh);
1786         brelse(bh2);
1787         *bh = NULL;
1788         ext4_std_error(dir->i_sb, err);
1789         return ERR_PTR(err);
1790 }
1791 
1792 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1793                       struct buffer_head *bh,
1794                       void *buf, int buf_size,
1795                       struct ext4_filename *fname,
1796                       struct ext4_dir_entry_2 **dest_de)
1797 {
1798         struct ext4_dir_entry_2 *de;
1799         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1800         int nlen, rlen;
1801         unsigned int offset = 0;
1802         char *top;
1803         int res;
1804 
1805         de = (struct ext4_dir_entry_2 *)buf;
1806         top = buf + buf_size - reclen;
1807         while ((char *) de <= top) {
1808                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1809                                          buf, buf_size, offset)) {
1810                         res = -EIO;
1811                         goto return_result;
1812                 }
1813                 /* Provide crypto context and crypto buffer to ext4 match */
1814                 res = ext4_match(fname, de);
1815                 if (res < 0)
1816                         goto return_result;
1817                 if (res > 0) {
1818                         res = -EEXIST;
1819                         goto return_result;
1820                 }
1821                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1822                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1823                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1824                         break;
1825                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1826                 offset += rlen;
1827         }
1828 
1829         if ((char *) de > top)
1830                 res = -ENOSPC;
1831         else {
1832                 *dest_de = de;
1833                 res = 0;
1834         }
1835 return_result:
1836         return res;
1837 }
1838 
1839 int ext4_insert_dentry(struct inode *dir,
1840                        struct inode *inode,
1841                        struct ext4_dir_entry_2 *de,
1842                        int buf_size,
1843                        struct ext4_filename *fname)
1844 {
1845 
1846         int nlen, rlen;
1847 
1848         nlen = EXT4_DIR_REC_LEN(de->name_len);
1849         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1850         if (de->inode) {
1851                 struct ext4_dir_entry_2 *de1 =
1852                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1853                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1854                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1855                 de = de1;
1856         }
1857         de->file_type = EXT4_FT_UNKNOWN;
1858         de->inode = cpu_to_le32(inode->i_ino);
1859         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1860         de->name_len = fname_len(fname);
1861         memcpy(de->name, fname_name(fname), fname_len(fname));
1862         return 0;
1863 }
1864 
1865 /*
1866  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1867  * it points to a directory entry which is guaranteed to be large
1868  * enough for new directory entry.  If de is NULL, then
1869  * add_dirent_to_buf will attempt search the directory block for
1870  * space.  It will return -ENOSPC if no space is available, and -EIO
1871  * and -EEXIST if directory entry already exists.
1872  */
1873 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1874                              struct inode *dir,
1875                              struct inode *inode, struct ext4_dir_entry_2 *de,
1876                              struct buffer_head *bh)
1877 {
1878         unsigned int    blocksize = dir->i_sb->s_blocksize;
1879         int             csum_size = 0;
1880         int             err;
1881 
1882         if (ext4_has_metadata_csum(inode->i_sb))
1883                 csum_size = sizeof(struct ext4_dir_entry_tail);
1884 
1885         if (!de) {
1886                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1887                                         blocksize - csum_size, fname, &de);
1888                 if (err)
1889                         return err;
1890         }
1891         BUFFER_TRACE(bh, "get_write_access");
1892         err = ext4_journal_get_write_access(handle, bh);
1893         if (err) {
1894                 ext4_std_error(dir->i_sb, err);
1895                 return err;
1896         }
1897 
1898         /* By now the buffer is marked for journaling. Due to crypto operations,
1899          * the following function call may fail */
1900         err = ext4_insert_dentry(dir, inode, de, blocksize, fname);
1901         if (err < 0)
1902                 return err;
1903 
1904         /*
1905          * XXX shouldn't update any times until successful
1906          * completion of syscall, but too many callers depend
1907          * on this.
1908          *
1909          * XXX similarly, too many callers depend on
1910          * ext4_new_inode() setting the times, but error
1911          * recovery deletes the inode, so the worst that can
1912          * happen is that the times are slightly out of date
1913          * and/or different from the directory change time.
1914          */
1915         dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
1916         ext4_update_dx_flag(dir);
1917         dir->i_version++;
1918         ext4_mark_inode_dirty(handle, dir);
1919         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1920         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1921         if (err)
1922                 ext4_std_error(dir->i_sb, err);
1923         return 0;
1924 }
1925 
1926 /*
1927  * This converts a one block unindexed directory to a 3 block indexed
1928  * directory, and adds the dentry to the indexed directory.
1929  */
1930 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1931                             struct dentry *dentry,
1932                             struct inode *inode, struct buffer_head *bh)
1933 {
1934         struct inode    *dir = d_inode(dentry->d_parent);
1935         struct buffer_head *bh2;
1936         struct dx_root  *root;
1937         struct dx_frame frames[2], *frame;
1938         struct dx_entry *entries;
1939         struct ext4_dir_entry_2 *de, *de2;
1940         struct ext4_dir_entry_tail *t;
1941         char            *data1, *top;
1942         unsigned        len;
1943         int             retval;
1944         unsigned        blocksize;
1945         ext4_lblk_t  block;
1946         struct fake_dirent *fde;
1947         int csum_size = 0;
1948 
1949         if (ext4_has_metadata_csum(inode->i_sb))
1950                 csum_size = sizeof(struct ext4_dir_entry_tail);
1951 
1952         blocksize =  dir->i_sb->s_blocksize;
1953         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1954         BUFFER_TRACE(bh, "get_write_access");
1955         retval = ext4_journal_get_write_access(handle, bh);
1956         if (retval) {
1957                 ext4_std_error(dir->i_sb, retval);
1958                 brelse(bh);
1959                 return retval;
1960         }
1961         root = (struct dx_root *) bh->b_data;
1962 
1963         /* The 0th block becomes the root, move the dirents out */
1964         fde = &root->dotdot;
1965         de = (struct ext4_dir_entry_2 *)((char *)fde +
1966                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1967         if ((char *) de >= (((char *) root) + blocksize)) {
1968                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1969                 brelse(bh);
1970                 return -EIO;
1971         }
1972         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1973 
1974         /* Allocate new block for the 0th block's dirents */
1975         bh2 = ext4_append(handle, dir, &block);
1976         if (IS_ERR(bh2)) {
1977                 brelse(bh);
1978                 return PTR_ERR(bh2);
1979         }
1980         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1981         data1 = bh2->b_data;
1982 
1983         memcpy (data1, de, len);
1984         de = (struct ext4_dir_entry_2 *) data1;
1985         top = data1 + len;
1986         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1987                 de = de2;
1988         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1989                                            (char *) de,
1990                                            blocksize);
1991 
1992         if (csum_size) {
1993                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1994                 initialize_dirent_tail(t, blocksize);
1995         }
1996 
1997         /* Initialize the root; the dot dirents already exist */
1998         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1999         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
2000                                            blocksize);
2001         memset (&root->info, 0, sizeof(root->info));
2002         root->info.info_length = sizeof(root->info);
2003         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
2004         entries = root->entries;
2005         dx_set_block(entries, 1);
2006         dx_set_count(entries, 1);
2007         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
2008 
2009         /* Initialize as for dx_probe */
2010         fname->hinfo.hash_version = root->info.hash_version;
2011         if (fname->hinfo.hash_version <= DX_HASH_TEA)
2012                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
2013         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
2014         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
2015 
2016         memset(frames, 0, sizeof(frames));
2017         frame = frames;
2018         frame->entries = entries;
2019         frame->at = entries;
2020         frame->bh = bh;
2021         bh = bh2;
2022 
2023         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2024         if (retval)
2025                 goto out_frames;        
2026         retval = ext4_handle_dirty_dirent_node(handle, dir, bh);
2027         if (retval)
2028                 goto out_frames;        
2029 
2030         de = do_split(handle,dir, &bh, frame, &fname->hinfo);
2031         if (IS_ERR(de)) {
2032                 retval = PTR_ERR(de);
2033                 goto out_frames;
2034         }
2035         dx_release(frames);
2036 
2037         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2038         brelse(bh);
2039         return retval;
2040 out_frames:
2041         /*
2042          * Even if the block split failed, we have to properly write
2043          * out all the changes we did so far. Otherwise we can end up
2044          * with corrupted filesystem.
2045          */
2046         ext4_mark_inode_dirty(handle, dir);
2047         dx_release(frames);
2048         return retval;
2049 }
2050 
2051 /*
2052  *      ext4_add_entry()
2053  *
2054  * adds a file entry to the specified directory, using the same
2055  * semantics as ext4_find_entry(). It returns NULL if it failed.
2056  *
2057  * NOTE!! The inode part of 'de' is left at 0 - which means you
2058  * may not sleep between calling this and putting something into
2059  * the entry, as someone else might have used it while you slept.
2060  */
2061 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2062                           struct inode *inode)
2063 {
2064         struct inode *dir = d_inode(dentry->d_parent);
2065         struct buffer_head *bh = NULL;
2066         struct ext4_dir_entry_2 *de;
2067         struct ext4_dir_entry_tail *t;
2068         struct super_block *sb;
2069         struct ext4_filename fname;
2070         int     retval;
2071         int     dx_fallback=0;
2072         unsigned blocksize;
2073         ext4_lblk_t block, blocks;
2074         int     csum_size = 0;
2075 
2076         if (ext4_has_metadata_csum(inode->i_sb))
2077                 csum_size = sizeof(struct ext4_dir_entry_tail);
2078 
2079         sb = dir->i_sb;
2080         blocksize = sb->s_blocksize;
2081         if (!dentry->d_name.len)
2082                 return -EINVAL;
2083 
2084         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2085         if (retval)
2086                 return retval;
2087 
2088         if (ext4_has_inline_data(dir)) {
2089                 retval = ext4_try_add_inline_entry(handle, &fname,
2090                                                    dentry, inode);
2091                 if (retval < 0)
2092                         goto out;
2093                 if (retval == 1) {
2094                         retval = 0;
2095                         goto out;
2096                 }
2097         }
2098 
2099         if (is_dx(dir)) {
2100                 retval = ext4_dx_add_entry(handle, &fname, dentry, inode);
2101                 if (!retval || (retval != ERR_BAD_DX_DIR))
2102                         goto out;
2103                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2104                 dx_fallback++;
2105                 ext4_mark_inode_dirty(handle, dir);
2106         }
2107         blocks = dir->i_size >> sb->s_blocksize_bits;
2108         for (block = 0; block < blocks; block++) {
2109                 bh = ext4_read_dirblock(dir, block, DIRENT);
2110                 if (IS_ERR(bh)) {
2111                         retval = PTR_ERR(bh);
2112                         bh = NULL;
2113                         goto out;
2114                 }
2115                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2116                                            NULL, bh);
2117                 if (retval != -ENOSPC)
2118                         goto out;
2119 
2120                 if (blocks == 1 && !dx_fallback &&
2121                     EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) {
2122                         retval = make_indexed_dir(handle, &fname, dentry,
2123                                                   inode, bh);
2124                         bh = NULL; /* make_indexed_dir releases bh */
2125                         goto out;
2126                 }
2127                 brelse(bh);
2128         }
2129         bh = ext4_append(handle, dir, &block);
2130         if (IS_ERR(bh)) {
2131                 retval = PTR_ERR(bh);
2132                 bh = NULL;
2133                 goto out;
2134         }
2135         de = (struct ext4_dir_entry_2 *) bh->b_data;
2136         de->inode = 0;
2137         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2138 
2139         if (csum_size) {
2140                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2141                 initialize_dirent_tail(t, blocksize);
2142         }
2143 
2144         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2145 out:
2146         ext4_fname_free_filename(&fname);
2147         brelse(bh);
2148         if (retval == 0)
2149                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2150         return retval;
2151 }
2152 
2153 /*
2154  * Returns 0 for success, or a negative error value
2155  */
2156 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2157                              struct dentry *dentry, struct inode *inode)
2158 {
2159         struct dx_frame frames[2], *frame;
2160         struct dx_entry *entries, *at;
2161         struct buffer_head *bh;
2162         struct inode *dir = d_inode(dentry->d_parent);
2163         struct super_block *sb = dir->i_sb;
2164         struct ext4_dir_entry_2 *de;
2165         int err;
2166 
2167         frame = dx_probe(fname, dir, NULL, frames);
2168         if (IS_ERR(frame))
2169                 return PTR_ERR(frame);
2170         entries = frame->entries;
2171         at = frame->at;
2172         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2173         if (IS_ERR(bh)) {
2174                 err = PTR_ERR(bh);
2175                 bh = NULL;
2176                 goto cleanup;
2177         }
2178 
2179         BUFFER_TRACE(bh, "get_write_access");
2180         err = ext4_journal_get_write_access(handle, bh);
2181         if (err)
2182                 goto journal_error;
2183 
2184         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2185         if (err != -ENOSPC)
2186                 goto cleanup;
2187 
2188         /* Block full, should compress but for now just split */
2189         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2190                        dx_get_count(entries), dx_get_limit(entries)));
2191         /* Need to split index? */
2192         if (dx_get_count(entries) == dx_get_limit(entries)) {
2193                 ext4_lblk_t newblock;
2194                 unsigned icount = dx_get_count(entries);
2195                 int levels = frame - frames;
2196                 struct dx_entry *entries2;
2197                 struct dx_node *node2;
2198                 struct buffer_head *bh2;
2199 
2200                 if (levels && (dx_get_count(frames->entries) ==
2201                                dx_get_limit(frames->entries))) {
2202                         ext4_warning_inode(dir, "Directory index full!");
2203                         err = -ENOSPC;
2204                         goto cleanup;
2205                 }
2206                 bh2 = ext4_append(handle, dir, &newblock);
2207                 if (IS_ERR(bh2)) {
2208                         err = PTR_ERR(bh2);
2209                         goto cleanup;
2210                 }
2211                 node2 = (struct dx_node *)(bh2->b_data);
2212                 entries2 = node2->entries;
2213                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2214                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2215                                                            sb->s_blocksize);
2216                 BUFFER_TRACE(frame->bh, "get_write_access");
2217                 err = ext4_journal_get_write_access(handle, frame->bh);
2218                 if (err)
2219                         goto journal_error;
2220                 if (levels) {
2221                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2222                         unsigned hash2 = dx_get_hash(entries + icount1);
2223                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2224                                        icount1, icount2));
2225 
2226                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2227                         err = ext4_journal_get_write_access(handle,
2228                                                              frames[0].bh);
2229                         if (err)
2230                                 goto journal_error;
2231 
2232                         memcpy((char *) entries2, (char *) (entries + icount1),
2233                                icount2 * sizeof(struct dx_entry));
2234                         dx_set_count(entries, icount1);
2235                         dx_set_count(entries2, icount2);
2236                         dx_set_limit(entries2, dx_node_limit(dir));
2237 
2238                         /* Which index block gets the new entry? */
2239                         if (at - entries >= icount1) {
2240                                 frame->at = at = at - entries - icount1 + entries2;
2241                                 frame->entries = entries = entries2;
2242                                 swap(frame->bh, bh2);
2243                         }
2244                         dx_insert_block(frames + 0, hash2, newblock);
2245                         dxtrace(dx_show_index("node", frames[1].entries));
2246                         dxtrace(dx_show_index("node",
2247                                ((struct dx_node *) bh2->b_data)->entries));
2248                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2249                         if (err)
2250                                 goto journal_error;
2251                         brelse (bh2);
2252                 } else {
2253                         dxtrace(printk(KERN_DEBUG
2254                                        "Creating second level index...\n"));
2255                         memcpy((char *) entries2, (char *) entries,
2256                                icount * sizeof(struct dx_entry));
2257                         dx_set_limit(entries2, dx_node_limit(dir));
2258 
2259                         /* Set up root */
2260                         dx_set_count(entries, 1);
2261                         dx_set_block(entries + 0, newblock);
2262                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
2263 
2264                         /* Add new access path frame */
2265                         frame = frames + 1;
2266                         frame->at = at = at - entries + entries2;
2267                         frame->entries = entries = entries2;
2268                         frame->bh = bh2;
2269                         err = ext4_journal_get_write_access(handle,
2270                                                              frame->bh);
2271                         if (err)
2272                                 goto journal_error;
2273                 }
2274                 err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
2275                 if (err) {
2276                         ext4_std_error(inode->i_sb, err);
2277                         goto cleanup;
2278                 }
2279         }
2280         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2281         if (IS_ERR(de)) {
2282                 err = PTR_ERR(de);
2283                 goto cleanup;
2284         }
2285         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2286         goto cleanup;
2287 
2288 journal_error:
2289         ext4_std_error(dir->i_sb, err);
2290 cleanup:
2291         brelse(bh);
2292         dx_release(frames);
2293         return err;
2294 }
2295 
2296 /*
2297  * ext4_generic_delete_entry deletes a directory entry by merging it
2298  * with the previous entry
2299  */
2300 int ext4_generic_delete_entry(handle_t *handle,
2301                               struct inode *dir,
2302                               struct ext4_dir_entry_2 *de_del,
2303                               struct buffer_head *bh,
2304                               void *entry_buf,
2305                               int buf_size,
2306                               int csum_size)
2307 {
2308         struct ext4_dir_entry_2 *de, *pde;
2309         unsigned int blocksize = dir->i_sb->s_blocksize;
2310         int i;
2311 
2312         i = 0;
2313         pde = NULL;
2314         de = (struct ext4_dir_entry_2 *)entry_buf;
2315         while (i < buf_size - csum_size) {
2316                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2317                                          bh->b_data, bh->b_size, i))
2318                         return -EIO;
2319                 if (de == de_del)  {
2320                         if (pde)
2321                                 pde->rec_len = ext4_rec_len_to_disk(
2322                                         ext4_rec_len_from_disk(pde->rec_len,
2323                                                                blocksize) +
2324                                         ext4_rec_len_from_disk(de->rec_len,
2325                                                                blocksize),
2326                                         blocksize);
2327                         else
2328                                 de->inode = 0;
2329                         dir->i_version++;
2330                         return 0;
2331                 }
2332                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2333                 pde = de;
2334                 de = ext4_next_entry(de, blocksize);
2335         }
2336         return -ENOENT;
2337 }
2338 
2339 static int ext4_delete_entry(handle_t *handle,
2340                              struct inode *dir,
2341                              struct ext4_dir_entry_2 *de_del,
2342                              struct buffer_head *bh)
2343 {
2344         int err, csum_size = 0;
2345 
2346         if (ext4_has_inline_data(dir)) {
2347                 int has_inline_data = 1;
2348                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2349                                                &has_inline_data);
2350                 if (has_inline_data)
2351                         return err;
2352         }
2353 
2354         if (ext4_has_metadata_csum(dir->i_sb))
2355                 csum_size = sizeof(struct ext4_dir_entry_tail);
2356 
2357         BUFFER_TRACE(bh, "get_write_access");
2358         err = ext4_journal_get_write_access(handle, bh);
2359         if (unlikely(err))
2360                 goto out;
2361 
2362         err = ext4_generic_delete_entry(handle, dir, de_del,
2363                                         bh, bh->b_data,
2364                                         dir->i_sb->s_blocksize, csum_size);
2365         if (err)
2366                 goto out;
2367 
2368         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2369         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2370         if (unlikely(err))
2371                 goto out;
2372 
2373         return 0;
2374 out:
2375         if (err != -ENOENT)
2376                 ext4_std_error(dir->i_sb, err);
2377         return err;
2378 }
2379 
2380 /*
2381  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
2382  * since this indicates that nlinks count was previously 1.
2383  */
2384 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2385 {
2386         inc_nlink(inode);
2387         if (is_dx(inode) && inode->i_nlink > 1) {
2388                 /* limit is 16-bit i_links_count */
2389                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
2390                         set_nlink(inode, 1);
2391                         EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb,
2392                                               EXT4_FEATURE_RO_COMPAT_DIR_NLINK);
2393                 }
2394         }
2395 }
2396 
2397 /*
2398  * If a directory had nlink == 1, then we should let it be 1. This indicates
2399  * directory has >EXT4_LINK_MAX subdirs.
2400  */
2401 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2402 {
2403         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2404                 drop_nlink(inode);
2405 }
2406 
2407 
2408 static int ext4_add_nondir(handle_t *handle,
2409                 struct dentry *dentry, struct inode *inode)
2410 {
2411         int err = ext4_add_entry(handle, dentry, inode);
2412         if (!err) {
2413                 ext4_mark_inode_dirty(handle, inode);
2414                 unlock_new_inode(inode);
2415                 d_instantiate(dentry, inode);
2416                 return 0;
2417         }
2418         drop_nlink(inode);
2419         unlock_new_inode(inode);
2420         iput(inode);
2421         return err;
2422 }
2423 
2424 /*
2425  * By the time this is called, we already have created
2426  * the directory cache entry for the new file, but it
2427  * is so far negative - it has no inode.
2428  *
2429  * If the create succeeds, we fill in the inode information
2430  * with d_instantiate().
2431  */
2432 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2433                        bool excl)
2434 {
2435         handle_t *handle;
2436         struct inode *inode;
2437         int err, credits, retries = 0;
2438 
2439         err = dquot_initialize(dir);
2440         if (err)
2441                 return err;
2442 
2443         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2444                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2445 retry:
2446         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2447                                             NULL, EXT4_HT_DIR, credits);
2448         handle = ext4_journal_current_handle();
2449         err = PTR_ERR(inode);
2450         if (!IS_ERR(inode)) {
2451                 inode->i_op = &ext4_file_inode_operations;
2452                 inode->i_fop = &ext4_file_operations;
2453                 ext4_set_aops(inode);
2454                 err = ext4_add_nondir(handle, dentry, inode);
2455                 if (!err && IS_DIRSYNC(dir))
2456                         ext4_handle_sync(handle);
2457         }
2458         if (handle)
2459                 ext4_journal_stop(handle);
2460         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2461                 goto retry;
2462         return err;
2463 }
2464 
2465 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2466                       umode_t mode, dev_t rdev)
2467 {
2468         handle_t *handle;
2469         struct inode *inode;
2470         int err, credits, retries = 0;
2471 
2472         if (!new_valid_dev(rdev))
2473                 return -EINVAL;
2474 
2475         err = dquot_initialize(dir);
2476         if (err)
2477                 return err;
2478 
2479         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2480                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2481 retry:
2482         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2483                                             NULL, EXT4_HT_DIR, credits);
2484         handle = ext4_journal_current_handle();
2485         err = PTR_ERR(inode);
2486         if (!IS_ERR(inode)) {
2487                 init_special_inode(inode, inode->i_mode, rdev);
2488                 inode->i_op = &ext4_special_inode_operations;
2489                 err = ext4_add_nondir(handle, dentry, inode);
2490                 if (!err && IS_DIRSYNC(dir))
2491                         ext4_handle_sync(handle);
2492         }
2493         if (handle)
2494                 ext4_journal_stop(handle);
2495         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2496                 goto retry;
2497         return err;
2498 }
2499 
2500 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2501 {
2502         handle_t *handle;
2503         struct inode *inode;
2504         int err, retries = 0;
2505 
2506         err = dquot_initialize(dir);
2507         if (err)
2508                 return err;
2509 
2510 retry:
2511         inode = ext4_new_inode_start_handle(dir, mode,
2512                                             NULL, 0, NULL,
2513                                             EXT4_HT_DIR,
2514                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2515                           4 + EXT4_XATTR_TRANS_BLOCKS);
2516         handle = ext4_journal_current_handle();
2517         err = PTR_ERR(inode);
2518         if (!IS_ERR(inode)) {
2519                 inode->i_op = &ext4_file_inode_operations;
2520                 inode->i_fop = &ext4_file_operations;
2521                 ext4_set_aops(inode);
2522                 d_tmpfile(dentry, inode);
2523                 err = ext4_orphan_add(handle, inode);
2524                 if (err)
2525                         goto err_unlock_inode;
2526                 mark_inode_dirty(inode);
2527                 unlock_new_inode(inode);
2528         }
2529         if (handle)
2530                 ext4_journal_stop(handle);
2531         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2532                 goto retry;
2533         return err;
2534 err_unlock_inode:
2535         ext4_journal_stop(handle);
2536         unlock_new_inode(inode);
2537         return err;
2538 }
2539 
2540 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2541                           struct ext4_dir_entry_2 *de,
2542                           int blocksize, int csum_size,
2543                           unsigned int parent_ino, int dotdot_real_len)
2544 {
2545         de->inode = cpu_to_le32(inode->i_ino);
2546         de->name_len = 1;
2547         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2548                                            blocksize);
2549         strcpy(de->name, ".");
2550         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2551 
2552         de = ext4_next_entry(de, blocksize);
2553         de->inode = cpu_to_le32(parent_ino);
2554         de->name_len = 2;
2555         if (!dotdot_real_len)
2556                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2557                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2558                                         blocksize);
2559         else
2560                 de->rec_len = ext4_rec_len_to_disk(
2561                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2562         strcpy(de->name, "..");
2563         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2564 
2565         return ext4_next_entry(de, blocksize);
2566 }
2567 
2568 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2569                              struct inode *inode)
2570 {
2571         struct buffer_head *dir_block = NULL;
2572         struct ext4_dir_entry_2 *de;
2573         struct ext4_dir_entry_tail *t;
2574         ext4_lblk_t block = 0;
2575         unsigned int blocksize = dir->i_sb->s_blocksize;
2576         int csum_size = 0;
2577         int err;
2578 
2579         if (ext4_has_metadata_csum(dir->i_sb))
2580                 csum_size = sizeof(struct ext4_dir_entry_tail);
2581 
2582         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2583                 err = ext4_try_create_inline_dir(handle, dir, inode);
2584                 if (err < 0 && err != -ENOSPC)
2585                         goto out;
2586                 if (!err)
2587                         goto out;
2588         }
2589 
2590         inode->i_size = 0;
2591         dir_block = ext4_append(handle, inode, &block);
2592         if (IS_ERR(dir_block))
2593                 return PTR_ERR(dir_block);
2594         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2595         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2596         set_nlink(inode, 2);
2597         if (csum_size) {
2598                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2599                 initialize_dirent_tail(t, blocksize);
2600         }
2601 
2602         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2603         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2604         if (err)
2605                 goto out;
2606         set_buffer_verified(dir_block);
2607 out:
2608         brelse(dir_block);
2609         return err;
2610 }
2611 
2612 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2613 {
2614         handle_t *handle;
2615         struct inode *inode;
2616         int err, credits, retries = 0;
2617 
2618         if (EXT4_DIR_LINK_MAX(dir))
2619                 return -EMLINK;
2620 
2621         err = dquot_initialize(dir);
2622         if (err)
2623                 return err;
2624 
2625         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2626                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2627 retry:
2628         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2629                                             &dentry->d_name,
2630                                             0, NULL, EXT4_HT_DIR, credits);
2631         handle = ext4_journal_current_handle();
2632         err = PTR_ERR(inode);
2633         if (IS_ERR(inode))
2634                 goto out_stop;
2635 
2636         inode->i_op = &ext4_dir_inode_operations;
2637         inode->i_fop = &ext4_dir_operations;
2638         err = ext4_init_new_dir(handle, dir, inode);
2639         if (err)
2640                 goto out_clear_inode;
2641         err = ext4_mark_inode_dirty(handle, inode);
2642         if (!err)
2643                 err = ext4_add_entry(handle, dentry, inode);
2644         if (err) {
2645 out_clear_inode:
2646                 clear_nlink(inode);
2647                 unlock_new_inode(inode);
2648                 ext4_mark_inode_dirty(handle, inode);
2649                 iput(inode);
2650                 goto out_stop;
2651         }
2652         ext4_inc_count(handle, dir);
2653         ext4_update_dx_flag(dir);
2654         err = ext4_mark_inode_dirty(handle, dir);
2655         if (err)
2656                 goto out_clear_inode;
2657         unlock_new_inode(inode);
2658         d_instantiate(dentry, inode);
2659         if (IS_DIRSYNC(dir))
2660                 ext4_handle_sync(handle);
2661 
2662 out_stop:
2663         if (handle)
2664                 ext4_journal_stop(handle);
2665         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2666                 goto retry;
2667         return err;
2668 }
2669 
2670 /*
2671  * routine to check that the specified directory is empty (for rmdir)
2672  */
2673 int ext4_empty_dir(struct inode *inode)
2674 {
2675         unsigned int offset;
2676         struct buffer_head *bh;
2677         struct ext4_dir_entry_2 *de, *de1;
2678         struct super_block *sb;
2679         int err = 0;
2680 
2681         if (ext4_has_inline_data(inode)) {
2682                 int has_inline_data = 1;
2683 
2684                 err = empty_inline_dir(inode, &has_inline_data);
2685                 if (has_inline_data)
2686                         return err;
2687         }
2688 
2689         sb = inode->i_sb;
2690         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2691                 EXT4_ERROR_INODE(inode, "invalid size");
2692                 return 1;
2693         }
2694         bh = ext4_read_dirblock(inode, 0, EITHER);
2695         if (IS_ERR(bh))
2696                 return 1;
2697 
2698         de = (struct ext4_dir_entry_2 *) bh->b_data;
2699         de1 = ext4_next_entry(de, sb->s_blocksize);
2700         if (le32_to_cpu(de->inode) != inode->i_ino ||
2701                         le32_to_cpu(de1->inode) == 0 ||
2702                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2703                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2704                 brelse(bh);
2705                 return 1;
2706         }
2707         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2708                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2709         de = ext4_next_entry(de1, sb->s_blocksize);
2710         while (offset < inode->i_size) {
2711                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2712                         unsigned int lblock;
2713                         err = 0;
2714                         brelse(bh);
2715                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2716                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2717                         if (IS_ERR(bh))
2718                                 return 1;
2719                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2720                 }
2721                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2722                                          bh->b_data, bh->b_size, offset)) {
2723                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2724                                                          sb->s_blocksize);
2725                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2726                         continue;
2727                 }
2728                 if (le32_to_cpu(de->inode)) {
2729                         brelse(bh);
2730                         return 0;
2731                 }
2732                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2733                 de = ext4_next_entry(de, sb->s_blocksize);
2734         }
2735         brelse(bh);
2736         return 1;
2737 }
2738 
2739 /*
2740  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2741  * such inodes, starting at the superblock, in case we crash before the
2742  * file is closed/deleted, or in case the inode truncate spans multiple
2743  * transactions and the last transaction is not recovered after a crash.
2744  *
2745  * At filesystem recovery time, we walk this list deleting unlinked
2746  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2747  *
2748  * Orphan list manipulation functions must be called under i_mutex unless
2749  * we are just creating the inode or deleting it.
2750  */
2751 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2752 {
2753         struct super_block *sb = inode->i_sb;
2754         struct ext4_sb_info *sbi = EXT4_SB(sb);
2755         struct ext4_iloc iloc;
2756         int err = 0, rc;
2757         bool dirty = false;
2758 
2759         if (!sbi->s_journal || is_bad_inode(inode))
2760                 return 0;
2761 
2762         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2763                      !mutex_is_locked(&inode->i_mutex));
2764         /*
2765          * Exit early if inode already is on orphan list. This is a big speedup
2766          * since we don't have to contend on the global s_orphan_lock.
2767          */
2768         if (!list_empty(&EXT4_I(inode)->i_orphan))
2769                 return 0;
2770 
2771         /*
2772          * Orphan handling is only valid for files with data blocks
2773          * being truncated, or files being unlinked. Note that we either
2774          * hold i_mutex, or the inode can not be referenced from outside,
2775          * so i_nlink should not be bumped due to race
2776          */
2777         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2778                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2779 
2780         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2781         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2782         if (err)
2783                 goto out;
2784 
2785         err = ext4_reserve_inode_write(handle, inode, &iloc);
2786         if (err)
2787                 goto out;
2788 
2789         mutex_lock(&sbi->s_orphan_lock);
2790         /*
2791          * Due to previous errors inode may be already a part of on-disk
2792          * orphan list. If so skip on-disk list modification.
2793          */
2794         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2795             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2796                 /* Insert this inode at the head of the on-disk orphan list */
2797                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2798                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2799                 dirty = true;
2800         }
2801         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2802         mutex_unlock(&sbi->s_orphan_lock);
2803 
2804         if (dirty) {
2805                 err = ext4_handle_dirty_super(handle, sb);
2806                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2807                 if (!err)
2808                         err = rc;
2809                 if (err) {
2810                         /*
2811                          * We have to remove inode from in-memory list if
2812                          * addition to on disk orphan list failed. Stray orphan
2813                          * list entries can cause panics at unmount time.
2814                          */
2815                         mutex_lock(&sbi->s_orphan_lock);
2816                         list_del(&EXT4_I(inode)->i_orphan);
2817                         mutex_unlock(&sbi->s_orphan_lock);
2818                 }
2819         }
2820         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2821         jbd_debug(4, "orphan inode %lu will point to %d\n",
2822                         inode->i_ino, NEXT_ORPHAN(inode));
2823 out:
2824         ext4_std_error(sb, err);
2825         return err;
2826 }
2827 
2828 /*
2829  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2830  * of such inodes stored on disk, because it is finally being cleaned up.
2831  */
2832 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2833 {
2834         struct list_head *prev;
2835         struct ext4_inode_info *ei = EXT4_I(inode);
2836         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2837         __u32 ino_next;
2838         struct ext4_iloc iloc;
2839         int err = 0;
2840 
2841         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2842                 return 0;
2843 
2844         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2845                      !mutex_is_locked(&inode->i_mutex));
2846         /* Do this quick check before taking global s_orphan_lock. */
2847         if (list_empty(&ei->i_orphan))
2848                 return 0;
2849 
2850         if (handle) {
2851                 /* Grab inode buffer early before taking global s_orphan_lock */
2852                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2853         }
2854 
2855         mutex_lock(&sbi->s_orphan_lock);
2856         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2857 
2858         prev = ei->i_orphan.prev;
2859         list_del_init(&ei->i_orphan);
2860 
2861         /* If we're on an error path, we may not have a valid
2862          * transaction handle with which to update the orphan list on
2863          * disk, but we still need to remove the inode from the linked
2864          * list in memory. */
2865         if (!handle || err) {
2866                 mutex_unlock(&sbi->s_orphan_lock);
2867                 goto out_err;
2868         }
2869 
2870         ino_next = NEXT_ORPHAN(inode);
2871         if (prev == &sbi->s_orphan) {
2872                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2873                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2874                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2875                 if (err) {
2876                         mutex_unlock(&sbi->s_orphan_lock);
2877                         goto out_brelse;
2878                 }
2879                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2880                 mutex_unlock(&sbi->s_orphan_lock);
2881                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2882         } else {
2883                 struct ext4_iloc iloc2;
2884                 struct inode *i_prev =
2885                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2886 
2887                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2888                           i_prev->i_ino, ino_next);
2889                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2890                 if (err) {
2891                         mutex_unlock(&sbi->s_orphan_lock);
2892                         goto out_brelse;
2893                 }
2894                 NEXT_ORPHAN(i_prev) = ino_next;
2895                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2896                 mutex_unlock(&sbi->s_orphan_lock);
2897         }
2898         if (err)
2899                 goto out_brelse;
2900         NEXT_ORPHAN(inode) = 0;
2901         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2902 out_err:
2903         ext4_std_error(inode->i_sb, err);
2904         return err;
2905 
2906 out_brelse:
2907         brelse(iloc.bh);
2908         goto out_err;
2909 }
2910 
2911 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2912 {
2913         int retval;
2914         struct inode *inode;
2915         struct buffer_head *bh;
2916         struct ext4_dir_entry_2 *de;
2917         handle_t *handle = NULL;
2918 
2919         /* Initialize quotas before so that eventual writes go in
2920          * separate transaction */
2921         retval = dquot_initialize(dir);
2922         if (retval)
2923                 return retval;
2924         retval = dquot_initialize(d_inode(dentry));
2925         if (retval)
2926                 return retval;
2927 
2928         retval = -ENOENT;
2929         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2930         if (IS_ERR(bh))
2931                 return PTR_ERR(bh);
2932         if (!bh)
2933                 goto end_rmdir;
2934 
2935         inode = d_inode(dentry);
2936 
2937         retval = -EIO;
2938         if (le32_to_cpu(de->inode) != inode->i_ino)
2939                 goto end_rmdir;
2940 
2941         retval = -ENOTEMPTY;
2942         if (!ext4_empty_dir(inode))
2943                 goto end_rmdir;
2944 
2945         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2946                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2947         if (IS_ERR(handle)) {
2948                 retval = PTR_ERR(handle);
2949                 handle = NULL;
2950                 goto end_rmdir;
2951         }
2952 
2953         if (IS_DIRSYNC(dir))
2954                 ext4_handle_sync(handle);
2955 
2956         retval = ext4_delete_entry(handle, dir, de, bh);
2957         if (retval)
2958                 goto end_rmdir;
2959         if (!EXT4_DIR_LINK_EMPTY(inode))
2960                 ext4_warning_inode(inode,
2961                              "empty directory '%.*s' has too many links (%u)",
2962                              dentry->d_name.len, dentry->d_name.name,
2963                              inode->i_nlink);
2964         inode->i_version++;
2965         clear_nlink(inode);
2966         /* There's no need to set i_disksize: the fact that i_nlink is
2967          * zero will ensure that the right thing happens during any
2968          * recovery. */
2969         inode->i_size = 0;
2970         ext4_orphan_add(handle, inode);
2971         inode->i_ctime = dir->i_ctime = dir->i_mtime = ext4_current_time(inode);
2972         ext4_mark_inode_dirty(handle, inode);
2973         ext4_dec_count(handle, dir);
2974         ext4_update_dx_flag(dir);
2975         ext4_mark_inode_dirty(handle, dir);
2976 
2977 end_rmdir:
2978         brelse(bh);
2979         if (handle)
2980                 ext4_journal_stop(handle);
2981         return retval;
2982 }
2983 
2984 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2985 {
2986         int retval;
2987         struct inode *inode;
2988         struct buffer_head *bh;
2989         struct ext4_dir_entry_2 *de;
2990         handle_t *handle = NULL;
2991 
2992         trace_ext4_unlink_enter(dir, dentry);
2993         /* Initialize quotas before so that eventual writes go
2994          * in separate transaction */
2995         retval = dquot_initialize(dir);
2996         if (retval)
2997                 return retval;
2998         retval = dquot_initialize(d_inode(dentry));
2999         if (retval)
3000                 return retval;
3001 
3002         retval = -ENOENT;
3003         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3004         if (IS_ERR(bh))
3005                 return PTR_ERR(bh);
3006         if (!bh)
3007                 goto end_unlink;
3008 
3009         inode = d_inode(dentry);
3010 
3011         retval = -EIO;
3012         if (le32_to_cpu(de->inode) != inode->i_ino)
3013                 goto end_unlink;
3014 
3015         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3016                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3017         if (IS_ERR(handle)) {
3018                 retval = PTR_ERR(handle);
3019                 handle = NULL;
3020                 goto end_unlink;
3021         }
3022 
3023         if (IS_DIRSYNC(dir))
3024                 ext4_handle_sync(handle);
3025 
3026         if (inode->i_nlink == 0) {
3027                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3028                                    dentry->d_name.len, dentry->d_name.name);
3029                 set_nlink(inode, 1);
3030         }
3031         retval = ext4_delete_entry(handle, dir, de, bh);
3032         if (retval)
3033                 goto end_unlink;
3034         dir->i_ctime = dir->i_mtime = ext4_current_time(dir);
3035         ext4_update_dx_flag(dir);
3036         ext4_mark_inode_dirty(handle, dir);
3037         drop_nlink(inode);
3038         if (!inode->i_nlink)
3039                 ext4_orphan_add(handle, inode);
3040         inode->i_ctime = ext4_current_time(inode);
3041         ext4_mark_inode_dirty(handle, inode);
3042 
3043 end_unlink:
3044         brelse(bh);
3045         if (handle)
3046                 ext4_journal_stop(handle);
3047         trace_ext4_unlink_exit(dentry, retval);
3048         return retval;
3049 }
3050 
3051 static int ext4_symlink(struct inode *dir,
3052                         struct dentry *dentry, const char *symname)
3053 {
3054         handle_t *handle;
3055         struct inode *inode;
3056         int err, len = strlen(symname);
3057         int credits;
3058         bool encryption_required;
3059         struct ext4_str disk_link;
3060         struct ext4_encrypted_symlink_data *sd = NULL;
3061 
3062         disk_link.len = len + 1;
3063         disk_link.name = (char *) symname;
3064 
3065         encryption_required = (ext4_encrypted_inode(dir) ||
3066                                DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
3067         if (encryption_required) {
3068                 err = ext4_get_encryption_info(dir);
3069                 if (err)
3070                         return err;
3071                 if (ext4_encryption_info(dir) == NULL)
3072                         return -EPERM;
3073                 disk_link.len = (ext4_fname_encrypted_size(dir, len) +
3074                                  sizeof(struct ext4_encrypted_symlink_data));
3075                 sd = kzalloc(disk_link.len, GFP_KERNEL);
3076                 if (!sd)
3077                         return -ENOMEM;
3078         }
3079 
3080         if (disk_link.len > dir->i_sb->s_blocksize) {
3081                 err = -ENAMETOOLONG;
3082                 goto err_free_sd;
3083         }
3084 
3085         err = dquot_initialize(dir);
3086         if (err)
3087                 goto err_free_sd;
3088 
3089         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3090                 /*
3091                  * For non-fast symlinks, we just allocate inode and put it on
3092                  * orphan list in the first transaction => we need bitmap,
3093                  * group descriptor, sb, inode block, quota blocks, and
3094                  * possibly selinux xattr blocks.
3095                  */
3096                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3097                           EXT4_XATTR_TRANS_BLOCKS;
3098         } else {
3099                 /*
3100                  * Fast symlink. We have to add entry to directory
3101                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3102                  * allocate new inode (bitmap, group descriptor, inode block,
3103                  * quota blocks, sb is already counted in previous macros).
3104                  */
3105                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3106                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3107         }
3108 
3109         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3110                                             &dentry->d_name, 0, NULL,
3111                                             EXT4_HT_DIR, credits);
3112         handle = ext4_journal_current_handle();
3113         if (IS_ERR(inode)) {
3114                 if (handle)
3115                         ext4_journal_stop(handle);
3116                 err = PTR_ERR(inode);
3117                 goto err_free_sd;
3118         }
3119 
3120         if (encryption_required) {
3121                 struct qstr istr;
3122                 struct ext4_str ostr;
3123 
3124                 istr.name = (const unsigned char *) symname;
3125                 istr.len = len;
3126                 ostr.name = sd->encrypted_path;
3127                 ostr.len = disk_link.len;
3128                 err = ext4_fname_usr_to_disk(inode, &istr, &ostr);
3129                 if (err < 0)
3130                         goto err_drop_inode;
3131                 sd->len = cpu_to_le16(ostr.len);
3132                 disk_link.name = (char *) sd;
3133                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3134         }
3135 
3136         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3137                 if (!encryption_required)
3138                         inode->i_op = &ext4_symlink_inode_operations;
3139                 ext4_set_aops(inode);
3140                 /*
3141                  * We cannot call page_symlink() with transaction started
3142                  * because it calls into ext4_write_begin() which can wait
3143                  * for transaction commit if we are running out of space
3144                  * and thus we deadlock. So we have to stop transaction now
3145                  * and restart it when symlink contents is written.
3146                  * 
3147                  * To keep fs consistent in case of crash, we have to put inode
3148                  * to orphan list in the mean time.
3149                  */
3150                 drop_nlink(inode);
3151                 err = ext4_orphan_add(handle, inode);
3152                 ext4_journal_stop(handle);
3153                 handle = NULL;
3154                 if (err)
3155                         goto err_drop_inode;
3156                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3157                 if (err)
3158                         goto err_drop_inode;
3159                 /*
3160                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3161                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3162                  */
3163                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3164                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3165                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3166                 if (IS_ERR(handle)) {
3167                         err = PTR_ERR(handle);
3168                         handle = NULL;
3169                         goto err_drop_inode;
3170                 }
3171                 set_nlink(inode, 1);
3172                 err = ext4_orphan_del(handle, inode);
3173                 if (err)
3174                         goto err_drop_inode;
3175         } else {
3176                 /* clear the extent format for fast symlink */
3177                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3178                 if (!encryption_required) {
3179                         inode->i_op = &ext4_fast_symlink_inode_operations;
3180                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3181                 }
3182                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3183                        disk_link.len);
3184                 inode->i_size = disk_link.len - 1;
3185         }
3186         EXT4_I(inode)->i_disksize = inode->i_size;
3187         err = ext4_add_nondir(handle, dentry, inode);
3188         if (!err && IS_DIRSYNC(dir))
3189                 ext4_handle_sync(handle);
3190 
3191         if (handle)
3192                 ext4_journal_stop(handle);
3193         kfree(sd);
3194         return err;
3195 err_drop_inode:
3196         if (handle)
3197                 ext4_journal_stop(handle);
3198         clear_nlink(inode);
3199         unlock_new_inode(inode);
3200         iput(inode);
3201 err_free_sd:
3202         kfree(sd);
3203         return err;
3204 }
3205 
3206 static int ext4_link(struct dentry *old_dentry,
3207                      struct inode *dir, struct dentry *dentry)
3208 {
3209         handle_t *handle;
3210         struct inode *inode = d_inode(old_dentry);
3211         int err, retries = 0;
3212 
3213         if (inode->i_nlink >= EXT4_LINK_MAX)
3214                 return -EMLINK;
3215         if (ext4_encrypted_inode(dir) &&
3216             !ext4_is_child_context_consistent_with_parent(dir, inode))
3217                 return -EPERM;
3218         err = dquot_initialize(dir);
3219         if (err)
3220                 return err;
3221 
3222 retry:
3223         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3224                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3225                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3226         if (IS_ERR(handle))
3227                 return PTR_ERR(handle);
3228 
3229         if (IS_DIRSYNC(dir))
3230                 ext4_handle_sync(handle);
3231 
3232         inode->i_ctime = ext4_current_time(inode);
3233         ext4_inc_count(handle, inode);
3234         ihold(inode);
3235 
3236         err = ext4_add_entry(handle, dentry, inode);
3237         if (!err) {
3238                 ext4_mark_inode_dirty(handle, inode);
3239                 /* this can happen only for tmpfile being
3240                  * linked the first time
3241                  */
3242                 if (inode->i_nlink == 1)
3243                         ext4_orphan_del(handle, inode);
3244                 d_instantiate(dentry, inode);
3245         } else {
3246                 drop_nlink(inode);
3247                 iput(inode);
3248         }
3249         ext4_journal_stop(handle);
3250         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3251                 goto retry;
3252         return err;
3253 }
3254 
3255 
3256 /*
3257  * Try to find buffer head where contains the parent block.
3258  * It should be the inode block if it is inlined or the 1st block
3259  * if it is a normal dir.
3260  */
3261 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3262                                         struct inode *inode,
3263                                         int *retval,
3264                                         struct ext4_dir_entry_2 **parent_de,
3265                                         int *inlined)
3266 {
3267         struct buffer_head *bh;
3268 
3269         if (!ext4_has_inline_data(inode)) {
3270                 bh = ext4_read_dirblock(inode, 0, EITHER);
3271                 if (IS_ERR(bh)) {
3272                         *retval = PTR_ERR(bh);
3273                         return NULL;
3274                 }
3275                 *parent_de = ext4_next_entry(
3276                                         (struct ext4_dir_entry_2 *)bh->b_data,
3277                                         inode->i_sb->s_blocksize);
3278                 return bh;
3279         }
3280 
3281         *inlined = 1;
3282         return ext4_get_first_inline_block(inode, parent_de, retval);
3283 }
3284 
3285 struct ext4_renament {
3286         struct inode *dir;
3287         struct dentry *dentry;
3288         struct inode *inode;
3289         bool is_dir;
3290         int dir_nlink_delta;
3291 
3292         /* entry for "dentry" */
3293         struct buffer_head *bh;
3294         struct ext4_dir_entry_2 *de;
3295         int inlined;
3296 
3297         /* entry for ".." in inode if it's a directory */
3298         struct buffer_head *dir_bh;
3299         struct ext4_dir_entry_2 *parent_de;
3300         int dir_inlined;
3301 };
3302 
3303 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3304 {
3305         int retval;
3306 
3307         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3308                                               &retval, &ent->parent_de,
3309                                               &ent->dir_inlined);
3310         if (!ent->dir_bh)
3311                 return retval;
3312         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3313                 return -EIO;
3314         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3315         return ext4_journal_get_write_access(handle, ent->dir_bh);
3316 }
3317 
3318 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3319                                   unsigned dir_ino)
3320 {
3321         int retval;
3322 
3323         ent->parent_de->inode = cpu_to_le32(dir_ino);
3324         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3325         if (!ent->dir_inlined) {
3326                 if (is_dx(ent->inode)) {
3327                         retval = ext4_handle_dirty_dx_node(handle,
3328                                                            ent->inode,
3329                                                            ent->dir_bh);
3330                 } else {
3331                         retval = ext4_handle_dirty_dirent_node(handle,
3332                                                                ent->inode,
3333                                                                ent->dir_bh);
3334                 }
3335         } else {
3336                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3337         }
3338         if (retval) {
3339                 ext4_std_error(ent->dir->i_sb, retval);
3340                 return retval;
3341         }
3342         return 0;
3343 }
3344 
3345 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3346                        unsigned ino, unsigned file_type)
3347 {
3348         int retval;
3349 
3350         BUFFER_TRACE(ent->bh, "get write access");
3351         retval = ext4_journal_get_write_access(handle, ent->bh);
3352         if (retval)
3353                 return retval;
3354         ent->de->inode = cpu_to_le32(ino);
3355         if (EXT4_HAS_INCOMPAT_FEATURE(ent->dir->i_sb,
3356                                       EXT4_FEATURE_INCOMPAT_FILETYPE))
3357                 ent->de->file_type = file_type;
3358         ent->dir->i_version++;
3359         ent->dir->i_ctime = ent->dir->i_mtime =
3360                 ext4_current_time(ent->dir);
3361         ext4_mark_inode_dirty(handle, ent->dir);
3362         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3363         if (!ent->inlined) {
3364                 retval = ext4_handle_dirty_dirent_node(handle,
3365                                                        ent->dir, ent->bh);
3366                 if (unlikely(retval)) {
3367                         ext4_std_error(ent->dir->i_sb, retval);
3368                         return retval;
3369                 }
3370         }
3371         brelse(ent->bh);
3372         ent->bh = NULL;
3373 
3374         return 0;
3375 }
3376 
3377 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3378                                   const struct qstr *d_name)
3379 {
3380         int retval = -ENOENT;
3381         struct buffer_head *bh;
3382         struct ext4_dir_entry_2 *de;
3383 
3384         bh = ext4_find_entry(dir, d_name, &de, NULL);
3385         if (IS_ERR(bh))
3386                 return PTR_ERR(bh);
3387         if (bh) {
3388                 retval = ext4_delete_entry(handle, dir, de, bh);
3389                 brelse(bh);
3390         }
3391         return retval;
3392 }
3393 
3394 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3395                                int force_reread)
3396 {
3397         int retval;
3398         /*
3399          * ent->de could have moved from under us during htree split, so make
3400          * sure that we are deleting the right entry.  We might also be pointing
3401          * to a stale entry in the unused part of ent->bh so just checking inum
3402          * and the name isn't enough.
3403          */
3404         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3405             ent->de->name_len != ent->dentry->d_name.len ||
3406             strncmp(ent->de->name, ent->dentry->d_name.name,
3407                     ent->de->name_len) ||
3408             force_reread) {
3409                 retval = ext4_find_delete_entry(handle, ent->dir,
3410                                                 &ent->dentry->d_name);
3411         } else {
3412                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3413                 if (retval == -ENOENT) {
3414                         retval = ext4_find_delete_entry(handle, ent->dir,
3415                                                         &ent->dentry->d_name);
3416                 }
3417         }
3418 
3419         if (retval) {
3420                 ext4_warning_inode(ent->dir,
3421                                    "Deleting old file: nlink %d, error=%d",
3422                                    ent->dir->i_nlink, retval);
3423         }
3424 }
3425 
3426 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3427 {
3428         if (ent->dir_nlink_delta) {
3429                 if (ent->dir_nlink_delta == -1)
3430                         ext4_dec_count(handle, ent->dir);
3431                 else
3432                         ext4_inc_count(handle, ent->dir);
3433                 ext4_mark_inode_dirty(handle, ent->dir);
3434         }
3435 }
3436 
3437 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3438                                               int credits, handle_t **h)
3439 {
3440         struct inode *wh;
3441         handle_t *handle;
3442         int retries = 0;
3443 
3444         /*
3445          * for inode block, sb block, group summaries,
3446          * and inode bitmap
3447          */
3448         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3449                     EXT4_XATTR_TRANS_BLOCKS + 4);
3450 retry:
3451         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3452                                          &ent->dentry->d_name, 0, NULL,
3453                                          EXT4_HT_DIR, credits);
3454 
3455         handle = ext4_journal_current_handle();
3456         if (IS_ERR(wh)) {
3457                 if (handle)
3458                         ext4_journal_stop(handle);
3459                 if (PTR_ERR(wh) == -ENOSPC &&
3460                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3461                         goto retry;
3462         } else {
3463                 *h = handle;
3464                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3465                 wh->i_op = &ext4_special_inode_operations;
3466         }
3467         return wh;
3468 }
3469 
3470 /*
3471  * Anybody can rename anything with this: the permission checks are left to the
3472  * higher-level routines.
3473  *
3474  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3475  * while new_{dentry,inode) refers to the destination dentry/inode
3476  * This comes from rename(const char *oldpath, const char *newpath)
3477  */
3478 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3479                        struct inode *new_dir, struct dentry *new_dentry,
3480                        unsigned int flags)
3481 {
3482         handle_t *handle = NULL;
3483         struct ext4_renament old = {
3484                 .dir = old_dir,
3485                 .dentry = old_dentry,
3486                 .inode = d_inode(old_dentry),
3487         };
3488         struct ext4_renament new = {
3489                 .dir = new_dir,
3490                 .dentry = new_dentry,
3491                 .inode = d_inode(new_dentry),
3492         };
3493         int force_reread;
3494         int retval;
3495         struct inode *whiteout = NULL;
3496         int credits;
3497         u8 old_file_type;
3498 
3499         retval = dquot_initialize(old.dir);
3500         if (retval)
3501                 return retval;
3502         retval = dquot_initialize(new.dir);
3503         if (retval)
3504                 return retval;
3505 
3506         /* Initialize quotas before so that eventual writes go
3507          * in separate transaction */
3508         if (new.inode) {
3509                 retval = dquot_initialize(new.inode);
3510                 if (retval)
3511                         return retval;
3512         }
3513 
3514         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3515         if (IS_ERR(old.bh))
3516                 return PTR_ERR(old.bh);
3517         /*
3518          *  Check for inode number is _not_ due to possible IO errors.
3519          *  We might rmdir the source, keep it as pwd of some process
3520          *  and merrily kill the link to whatever was created under the
3521          *  same name. Goodbye sticky bit ;-<
3522          */
3523         retval = -ENOENT;
3524         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3525                 goto end_rename;
3526 
3527         if ((old.dir != new.dir) &&
3528             ext4_encrypted_inode(new.dir) &&
3529             !ext4_is_child_context_consistent_with_parent(new.dir,
3530                                                           old.inode)) {
3531                 retval = -EPERM;
3532                 goto end_rename;
3533         }
3534 
3535         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3536                                  &new.de, &new.inlined);
3537         if (IS_ERR(new.bh)) {
3538                 retval = PTR_ERR(new.bh);
3539                 new.bh = NULL;
3540                 goto end_rename;
3541         }
3542         if (new.bh) {
3543                 if (!new.inode) {
3544                         brelse(new.bh);
3545                         new.bh = NULL;
3546                 }
3547         }
3548         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3549                 ext4_alloc_da_blocks(old.inode);
3550 
3551         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3552                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3553         if (!(flags & RENAME_WHITEOUT)) {
3554                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3555                 if (IS_ERR(handle)) {
3556                         retval = PTR_ERR(handle);
3557                         handle = NULL;
3558                         goto end_rename;
3559                 }
3560         } else {
3561                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3562                 if (IS_ERR(whiteout)) {
3563                         retval = PTR_ERR(whiteout);
3564                         whiteout = NULL;
3565                         goto end_rename;
3566                 }
3567         }
3568 
3569         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3570                 ext4_handle_sync(handle);
3571 
3572         if (S_ISDIR(old.inode->i_mode)) {
3573                 if (new.inode) {
3574                         retval = -ENOTEMPTY;
3575                         if (!ext4_empty_dir(new.inode))
3576                                 goto end_rename;
3577                 } else {
3578                         retval = -EMLINK;
3579                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3580                                 goto end_rename;
3581                 }
3582                 retval = ext4_rename_dir_prepare(handle, &old);
3583                 if (retval)
3584                         goto end_rename;
3585         }
3586         /*
3587          * If we're renaming a file within an inline_data dir and adding or
3588          * setting the new dirent causes a conversion from inline_data to
3589          * extents/blockmap, we need to force the dirent delete code to
3590          * re-read the directory, or else we end up trying to delete a dirent
3591          * from what is now the extent tree root (or a block map).
3592          */
3593         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3594                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3595 
3596         old_file_type = old.de->file_type;
3597         if (whiteout) {
3598                 /*
3599                  * Do this before adding a new entry, so the old entry is sure
3600                  * to be still pointing to the valid old entry.
3601                  */
3602                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3603                                      EXT4_FT_CHRDEV);
3604                 if (retval)
3605                         goto end_rename;
3606                 ext4_mark_inode_dirty(handle, whiteout);
3607         }
3608         if (!new.bh) {
3609                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3610                 if (retval)
3611                         goto end_rename;
3612         } else {
3613                 retval = ext4_setent(handle, &new,
3614                                      old.inode->i_ino, old_file_type);
3615                 if (retval)
3616                         goto end_rename;
3617         }
3618         if (force_reread)
3619                 force_reread = !ext4_test_inode_flag(new.dir,
3620                                                      EXT4_INODE_INLINE_DATA);
3621 
3622         /*
3623          * Like most other Unix systems, set the ctime for inodes on a
3624          * rename.
3625          */
3626         old.inode->i_ctime = ext4_current_time(old.inode);
3627         ext4_mark_inode_dirty(handle, old.inode);
3628 
3629         if (!whiteout) {
3630                 /*
3631                  * ok, that's it
3632                  */
3633                 ext4_rename_delete(handle, &old, force_reread);
3634         }
3635 
3636         if (new.inode) {
3637                 ext4_dec_count(handle, new.inode);
3638                 new.inode->i_ctime = ext4_current_time(new.inode);
3639         }
3640         old.dir->i_ctime = old.dir->i_mtime = ext4_current_time(old.dir);
3641         ext4_update_dx_flag(old.dir);
3642         if (old.dir_bh) {
3643                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3644                 if (retval)
3645                         goto end_rename;
3646 
3647                 ext4_dec_count(handle, old.dir);
3648                 if (new.inode) {
3649                         /* checked ext4_empty_dir above, can't have another
3650                          * parent, ext4_dec_count() won't work for many-linked
3651                          * dirs */
3652                         clear_nlink(new.inode);
3653                 } else {
3654                         ext4_inc_count(handle, new.dir);
3655                         ext4_update_dx_flag(new.dir);
3656                         ext4_mark_inode_dirty(handle, new.dir);
3657                 }
3658         }
3659         ext4_mark_inode_dirty(handle, old.dir);
3660         if (new.inode) {
3661                 ext4_mark_inode_dirty(handle, new.inode);
3662                 if (!new.inode->i_nlink)
3663                         ext4_orphan_add(handle, new.inode);
3664         }
3665         retval = 0;
3666 
3667 end_rename:
3668         brelse(old.dir_bh);
3669         brelse(old.bh);
3670         brelse(new.bh);
3671         if (whiteout) {
3672                 if (retval)
3673                         drop_nlink(whiteout);
3674                 unlock_new_inode(whiteout);
3675                 iput(whiteout);
3676         }
3677         if (handle)
3678                 ext4_journal_stop(handle);
3679         return retval;
3680 }
3681 
3682 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3683                              struct inode *new_dir, struct dentry *new_dentry)
3684 {
3685         handle_t *handle = NULL;
3686         struct ext4_renament old = {
3687                 .dir = old_dir,
3688                 .dentry = old_dentry,
3689                 .inode = d_inode(old_dentry),
3690         };
3691         struct ext4_renament new = {
3692                 .dir = new_dir,
3693                 .dentry = new_dentry,
3694                 .inode = d_inode(new_dentry),
3695         };
3696         u8 new_file_type;
3697         int retval;
3698 
3699         if ((ext4_encrypted_inode(old_dir) ||
3700              ext4_encrypted_inode(new_dir)) &&
3701             (old_dir != new_dir) &&
3702             (!ext4_is_child_context_consistent_with_parent(new_dir,
3703                                                            old.inode) ||
3704              !ext4_is_child_context_consistent_with_parent(old_dir,
3705                                                            new.inode)))
3706                 return -EPERM;
3707 
3708         retval = dquot_initialize(old.dir);
3709         if (retval)
3710                 return retval;
3711         retval = dquot_initialize(new.dir);
3712         if (retval)
3713                 return retval;
3714 
3715         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3716                                  &old.de, &old.inlined);
3717         if (IS_ERR(old.bh))
3718                 return PTR_ERR(old.bh);
3719         /*
3720          *  Check for inode number is _not_ due to possible IO errors.
3721          *  We might rmdir the source, keep it as pwd of some process
3722          *  and merrily kill the link to whatever was created under the
3723          *  same name. Goodbye sticky bit ;-<
3724          */
3725         retval = -ENOENT;
3726         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3727                 goto end_rename;
3728 
3729         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3730                                  &new.de, &new.inlined);
3731         if (IS_ERR(new.bh)) {
3732                 retval = PTR_ERR(new.bh);
3733                 new.bh = NULL;
3734                 goto end_rename;
3735         }
3736 
3737         /* RENAME_EXCHANGE case: old *and* new must both exist */
3738         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3739                 goto end_rename;
3740 
3741         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3742                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3743                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3744         if (IS_ERR(handle)) {
3745                 retval = PTR_ERR(handle);
3746                 handle = NULL;
3747                 goto end_rename;
3748         }
3749 
3750         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3751                 ext4_handle_sync(handle);
3752 
3753         if (S_ISDIR(old.inode->i_mode)) {
3754                 old.is_dir = true;
3755                 retval = ext4_rename_dir_prepare(handle, &old);
3756                 if (retval)
3757                         goto end_rename;
3758         }
3759         if (S_ISDIR(new.inode->i_mode)) {
3760                 new.is_dir = true;
3761                 retval = ext4_rename_dir_prepare(handle, &new);
3762                 if (retval)
3763                         goto end_rename;
3764         }
3765 
3766         /*
3767          * Other than the special case of overwriting a directory, parents'
3768          * nlink only needs to be modified if this is a cross directory rename.
3769          */
3770         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3771                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3772                 new.dir_nlink_delta = -old.dir_nlink_delta;
3773                 retval = -EMLINK;
3774                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3775                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3776                         goto end_rename;
3777         }
3778 
3779         new_file_type = new.de->file_type;
3780         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3781         if (retval)
3782                 goto end_rename;
3783 
3784         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3785         if (retval)
3786                 goto end_rename;
3787 
3788         /*
3789          * Like most other Unix systems, set the ctime for inodes on a
3790          * rename.
3791          */
3792         old.inode->i_ctime = ext4_current_time(old.inode);
3793         new.inode->i_ctime = ext4_current_time(new.inode);
3794         ext4_mark_inode_dirty(handle, old.inode);
3795         ext4_mark_inode_dirty(handle, new.inode);
3796 
3797         if (old.dir_bh) {
3798                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3799                 if (retval)
3800                         goto end_rename;
3801         }
3802         if (new.dir_bh) {
3803                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3804                 if (retval)
3805                         goto end_rename;
3806         }
3807         ext4_update_dir_count(handle, &old);
3808         ext4_update_dir_count(handle, &new);
3809         retval = 0;
3810 
3811 end_rename:
3812         brelse(old.dir_bh);
3813         brelse(new.dir_bh);
3814         brelse(old.bh);
3815         brelse(new.bh);
3816         if (handle)
3817                 ext4_journal_stop(handle);
3818         return retval;
3819 }
3820 
3821 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3822                         struct inode *new_dir, struct dentry *new_dentry,
3823                         unsigned int flags)
3824 {
3825         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3826                 return -EINVAL;
3827 
3828         if (flags & RENAME_EXCHANGE) {
3829                 return ext4_cross_rename(old_dir, old_dentry,
3830                                          new_dir, new_dentry);
3831         }
3832 
3833         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3834 }
3835 
3836 /*
3837  * directories can handle most operations...
3838  */
3839 const struct inode_operations ext4_dir_inode_operations = {
3840         .create         = ext4_create,
3841         .lookup         = ext4_lookup,
3842         .link           = ext4_link,
3843         .unlink         = ext4_unlink,
3844         .symlink        = ext4_symlink,
3845         .mkdir          = ext4_mkdir,
3846         .rmdir          = ext4_rmdir,
3847         .mknod          = ext4_mknod,
3848         .tmpfile        = ext4_tmpfile,
3849         .rename2        = ext4_rename2,
3850         .setattr        = ext4_setattr,
3851         .setxattr       = generic_setxattr,
3852         .getxattr       = generic_getxattr,
3853         .listxattr      = ext4_listxattr,
3854         .removexattr    = generic_removexattr,
3855         .get_acl        = ext4_get_acl,
3856         .set_acl        = ext4_set_acl,
3857         .fiemap         = ext4_fiemap,
3858 };
3859 
3860 const struct inode_operations ext4_special_inode_operations = {
3861         .setattr        = ext4_setattr,
3862         .setxattr       = generic_setxattr,
3863         .getxattr       = generic_getxattr,
3864         .listxattr      = ext4_listxattr,
3865         .removexattr    = generic_removexattr,
3866         .get_acl        = ext4_get_acl,
3867         .set_acl        = ext4_set_acl,
3868 };
3869 

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