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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(-EFSCORRUPTED);
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(-EFSCORRUPTED);
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(-EFSBADCRC);
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(-EFSBADCRC);
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 inode *dir, 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 (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 (ext4_encrypted_inode(dir)) {
1562                int res = ext4_get_encryption_info(dir);
1563 
1564                 /*
1565                  * This should be a properly defined flag for
1566                  * dentry->d_flags when we uplift this to the VFS.
1567                  * d_fsdata is set to (void *) 1 if if the dentry is
1568                  * created while the directory was encrypted and we
1569                  * don't have access to the key.
1570                  */
1571                dentry->d_fsdata = NULL;
1572                if (ext4_encryption_info(dir))
1573                        dentry->d_fsdata = (void *) 1;
1574                d_set_d_op(dentry, &ext4_encrypted_d_ops);
1575                if (res && res != -ENOKEY)
1576                        return ERR_PTR(res);
1577        }
1578 
1579         if (dentry->d_name.len > EXT4_NAME_LEN)
1580                 return ERR_PTR(-ENAMETOOLONG);
1581 
1582         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1583         if (IS_ERR(bh))
1584                 return (struct dentry *) bh;
1585         inode = NULL;
1586         if (bh) {
1587                 __u32 ino = le32_to_cpu(de->inode);
1588                 brelse(bh);
1589                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1590                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1591                         return ERR_PTR(-EFSCORRUPTED);
1592                 }
1593                 if (unlikely(ino == dir->i_ino)) {
1594                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1595                                          dentry);
1596                         return ERR_PTR(-EFSCORRUPTED);
1597                 }
1598                 inode = ext4_iget_normal(dir->i_sb, ino);
1599                 if (inode == ERR_PTR(-ESTALE)) {
1600                         EXT4_ERROR_INODE(dir,
1601                                          "deleted inode referenced: %u",
1602                                          ino);
1603                         return ERR_PTR(-EFSCORRUPTED);
1604                 }
1605                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1606                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1607                     !ext4_is_child_context_consistent_with_parent(dir,
1608                                                                   inode)) {
1609                         int nokey = ext4_encrypted_inode(inode) &&
1610                                 !ext4_encryption_info(inode);
1611 
1612                         iput(inode);
1613                         if (nokey)
1614                                 return ERR_PTR(-ENOKEY);
1615                         ext4_warning(inode->i_sb,
1616                                      "Inconsistent encryption contexts: %lu/%lu\n",
1617                                      (unsigned long) dir->i_ino,
1618                                      (unsigned long) inode->i_ino);
1619                         return ERR_PTR(-EPERM);
1620                 }
1621         }
1622         return d_splice_alias(inode, dentry);
1623 }
1624 
1625 
1626 struct dentry *ext4_get_parent(struct dentry *child)
1627 {
1628         __u32 ino;
1629         static const struct qstr dotdot = QSTR_INIT("..", 2);
1630         struct ext4_dir_entry_2 * de;
1631         struct buffer_head *bh;
1632 
1633         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1634         if (IS_ERR(bh))
1635                 return (struct dentry *) bh;
1636         if (!bh)
1637                 return ERR_PTR(-ENOENT);
1638         ino = le32_to_cpu(de->inode);
1639         brelse(bh);
1640 
1641         if (!ext4_valid_inum(d_inode(child)->i_sb, ino)) {
1642                 EXT4_ERROR_INODE(d_inode(child),
1643                                  "bad parent inode number: %u", ino);
1644                 return ERR_PTR(-EFSCORRUPTED);
1645         }
1646 
1647         return d_obtain_alias(ext4_iget_normal(d_inode(child)->i_sb, ino));
1648 }
1649 
1650 /*
1651  * Move count entries from end of map between two memory locations.
1652  * Returns pointer to last entry moved.
1653  */
1654 static struct ext4_dir_entry_2 *
1655 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1656                 unsigned blocksize)
1657 {
1658         unsigned rec_len = 0;
1659 
1660         while (count--) {
1661                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1662                                                 (from + (map->offs<<2));
1663                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1664                 memcpy (to, de, rec_len);
1665                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1666                                 ext4_rec_len_to_disk(rec_len, blocksize);
1667                 de->inode = 0;
1668                 map++;
1669                 to += rec_len;
1670         }
1671         return (struct ext4_dir_entry_2 *) (to - rec_len);
1672 }
1673 
1674 /*
1675  * Compact each dir entry in the range to the minimal rec_len.
1676  * Returns pointer to last entry in range.
1677  */
1678 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1679 {
1680         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1681         unsigned rec_len = 0;
1682 
1683         prev = to = de;
1684         while ((char*)de < base + blocksize) {
1685                 next = ext4_next_entry(de, blocksize);
1686                 if (de->inode && de->name_len) {
1687                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1688                         if (de > to)
1689                                 memmove(to, de, rec_len);
1690                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1691                         prev = to;
1692                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1693                 }
1694                 de = next;
1695         }
1696         return prev;
1697 }
1698 
1699 /*
1700  * Split a full leaf block to make room for a new dir entry.
1701  * Allocate a new block, and move entries so that they are approx. equally full.
1702  * Returns pointer to de in block into which the new entry will be inserted.
1703  */
1704 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1705                         struct buffer_head **bh,struct dx_frame *frame,
1706                         struct dx_hash_info *hinfo)
1707 {
1708         unsigned blocksize = dir->i_sb->s_blocksize;
1709         unsigned count, continued;
1710         struct buffer_head *bh2;
1711         ext4_lblk_t newblock;
1712         u32 hash2;
1713         struct dx_map_entry *map;
1714         char *data1 = (*bh)->b_data, *data2;
1715         unsigned split, move, size;
1716         struct ext4_dir_entry_2 *de = NULL, *de2;
1717         struct ext4_dir_entry_tail *t;
1718         int     csum_size = 0;
1719         int     err = 0, i;
1720 
1721         if (ext4_has_metadata_csum(dir->i_sb))
1722                 csum_size = sizeof(struct ext4_dir_entry_tail);
1723 
1724         bh2 = ext4_append(handle, dir, &newblock);
1725         if (IS_ERR(bh2)) {
1726                 brelse(*bh);
1727                 *bh = NULL;
1728                 return (struct ext4_dir_entry_2 *) bh2;
1729         }
1730 
1731         BUFFER_TRACE(*bh, "get_write_access");
1732         err = ext4_journal_get_write_access(handle, *bh);
1733         if (err)
1734                 goto journal_error;
1735 
1736         BUFFER_TRACE(frame->bh, "get_write_access");
1737         err = ext4_journal_get_write_access(handle, frame->bh);
1738         if (err)
1739                 goto journal_error;
1740 
1741         data2 = bh2->b_data;
1742 
1743         /* create map in the end of data2 block */
1744         map = (struct dx_map_entry *) (data2 + blocksize);
1745         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1746                              blocksize, hinfo, map);
1747         map -= count;
1748         dx_sort_map(map, count);
1749         /* Split the existing block in the middle, size-wise */
1750         size = 0;
1751         move = 0;
1752         for (i = count-1; i >= 0; i--) {
1753                 /* is more than half of this entry in 2nd half of the block? */
1754                 if (size + map[i].size/2 > blocksize/2)
1755                         break;
1756                 size += map[i].size;
1757                 move++;
1758         }
1759         /* map index at which we will split */
1760         split = count - move;
1761         hash2 = map[split].hash;
1762         continued = hash2 == map[split - 1].hash;
1763         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1764                         (unsigned long)dx_get_block(frame->at),
1765                                         hash2, split, count-split));
1766 
1767         /* Fancy dance to stay within two buffers */
1768         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1769                               blocksize);
1770         de = dx_pack_dirents(data1, blocksize);
1771         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1772                                            (char *) de,
1773                                            blocksize);
1774         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1775                                             (char *) de2,
1776                                             blocksize);
1777         if (csum_size) {
1778                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1779                 initialize_dirent_tail(t, blocksize);
1780 
1781                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1782                 initialize_dirent_tail(t, blocksize);
1783         }
1784 
1785         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1786                         blocksize, 1));
1787         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1788                         blocksize, 1));
1789 
1790         /* Which block gets the new entry? */
1791         if (hinfo->hash >= hash2) {
1792                 swap(*bh, bh2);
1793                 de = de2;
1794         }
1795         dx_insert_block(frame, hash2 + continued, newblock);
1796         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1797         if (err)
1798                 goto journal_error;
1799         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1800         if (err)
1801                 goto journal_error;
1802         brelse(bh2);
1803         dxtrace(dx_show_index("frame", frame->entries));
1804         return de;
1805 
1806 journal_error:
1807         brelse(*bh);
1808         brelse(bh2);
1809         *bh = NULL;
1810         ext4_std_error(dir->i_sb, err);
1811         return ERR_PTR(err);
1812 }
1813 
1814 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1815                       struct buffer_head *bh,
1816                       void *buf, int buf_size,
1817                       struct ext4_filename *fname,
1818                       struct ext4_dir_entry_2 **dest_de)
1819 {
1820         struct ext4_dir_entry_2 *de;
1821         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1822         int nlen, rlen;
1823         unsigned int offset = 0;
1824         char *top;
1825         int res;
1826 
1827         de = (struct ext4_dir_entry_2 *)buf;
1828         top = buf + buf_size - reclen;
1829         while ((char *) de <= top) {
1830                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1831                                          buf, buf_size, offset)) {
1832                         res = -EFSCORRUPTED;
1833                         goto return_result;
1834                 }
1835                 /* Provide crypto context and crypto buffer to ext4 match */
1836                 res = ext4_match(fname, de);
1837                 if (res < 0)
1838                         goto return_result;
1839                 if (res > 0) {
1840                         res = -EEXIST;
1841                         goto return_result;
1842                 }
1843                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1844                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1845                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1846                         break;
1847                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1848                 offset += rlen;
1849         }
1850 
1851         if ((char *) de > top)
1852                 res = -ENOSPC;
1853         else {
1854                 *dest_de = de;
1855                 res = 0;
1856         }
1857 return_result:
1858         return res;
1859 }
1860 
1861 int ext4_insert_dentry(struct inode *dir,
1862                        struct inode *inode,
1863                        struct ext4_dir_entry_2 *de,
1864                        int buf_size,
1865                        struct ext4_filename *fname)
1866 {
1867 
1868         int nlen, rlen;
1869 
1870         nlen = EXT4_DIR_REC_LEN(de->name_len);
1871         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1872         if (de->inode) {
1873                 struct ext4_dir_entry_2 *de1 =
1874                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1875                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1876                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1877                 de = de1;
1878         }
1879         de->file_type = EXT4_FT_UNKNOWN;
1880         de->inode = cpu_to_le32(inode->i_ino);
1881         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1882         de->name_len = fname_len(fname);
1883         memcpy(de->name, fname_name(fname), fname_len(fname));
1884         return 0;
1885 }
1886 
1887 /*
1888  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1889  * it points to a directory entry which is guaranteed to be large
1890  * enough for new directory entry.  If de is NULL, then
1891  * add_dirent_to_buf will attempt search the directory block for
1892  * space.  It will return -ENOSPC if no space is available, and -EIO
1893  * and -EEXIST if directory entry already exists.
1894  */
1895 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1896                              struct inode *dir,
1897                              struct inode *inode, struct ext4_dir_entry_2 *de,
1898                              struct buffer_head *bh)
1899 {
1900         unsigned int    blocksize = dir->i_sb->s_blocksize;
1901         int             csum_size = 0;
1902         int             err;
1903 
1904         if (ext4_has_metadata_csum(inode->i_sb))
1905                 csum_size = sizeof(struct ext4_dir_entry_tail);
1906 
1907         if (!de) {
1908                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1909                                         blocksize - csum_size, fname, &de);
1910                 if (err)
1911                         return err;
1912         }
1913         BUFFER_TRACE(bh, "get_write_access");
1914         err = ext4_journal_get_write_access(handle, bh);
1915         if (err) {
1916                 ext4_std_error(dir->i_sb, err);
1917                 return err;
1918         }
1919 
1920         /* By now the buffer is marked for journaling. Due to crypto operations,
1921          * the following function call may fail */
1922         err = ext4_insert_dentry(dir, inode, de, blocksize, fname);
1923         if (err < 0)
1924                 return err;
1925 
1926         /*
1927          * XXX shouldn't update any times until successful
1928          * completion of syscall, but too many callers depend
1929          * on this.
1930          *
1931          * XXX similarly, too many callers depend on
1932          * ext4_new_inode() setting the times, but error
1933          * recovery deletes the inode, so the worst that can
1934          * happen is that the times are slightly out of date
1935          * and/or different from the directory change time.
1936          */
1937         dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
1938         ext4_update_dx_flag(dir);
1939         dir->i_version++;
1940         ext4_mark_inode_dirty(handle, dir);
1941         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1942         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1943         if (err)
1944                 ext4_std_error(dir->i_sb, err);
1945         return 0;
1946 }
1947 
1948 /*
1949  * This converts a one block unindexed directory to a 3 block indexed
1950  * directory, and adds the dentry to the indexed directory.
1951  */
1952 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1953                             struct inode *dir,
1954                             struct inode *inode, struct buffer_head *bh)
1955 {
1956         struct buffer_head *bh2;
1957         struct dx_root  *root;
1958         struct dx_frame frames[2], *frame;
1959         struct dx_entry *entries;
1960         struct ext4_dir_entry_2 *de, *de2;
1961         struct ext4_dir_entry_tail *t;
1962         char            *data1, *top;
1963         unsigned        len;
1964         int             retval;
1965         unsigned        blocksize;
1966         ext4_lblk_t  block;
1967         struct fake_dirent *fde;
1968         int csum_size = 0;
1969 
1970         if (ext4_has_metadata_csum(inode->i_sb))
1971                 csum_size = sizeof(struct ext4_dir_entry_tail);
1972 
1973         blocksize =  dir->i_sb->s_blocksize;
1974         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1975         BUFFER_TRACE(bh, "get_write_access");
1976         retval = ext4_journal_get_write_access(handle, bh);
1977         if (retval) {
1978                 ext4_std_error(dir->i_sb, retval);
1979                 brelse(bh);
1980                 return retval;
1981         }
1982         root = (struct dx_root *) bh->b_data;
1983 
1984         /* The 0th block becomes the root, move the dirents out */
1985         fde = &root->dotdot;
1986         de = (struct ext4_dir_entry_2 *)((char *)fde +
1987                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1988         if ((char *) de >= (((char *) root) + blocksize)) {
1989                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1990                 brelse(bh);
1991                 return -EFSCORRUPTED;
1992         }
1993         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1994 
1995         /* Allocate new block for the 0th block's dirents */
1996         bh2 = ext4_append(handle, dir, &block);
1997         if (IS_ERR(bh2)) {
1998                 brelse(bh);
1999                 return PTR_ERR(bh2);
2000         }
2001         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
2002         data1 = bh2->b_data;
2003 
2004         memcpy (data1, de, len);
2005         de = (struct ext4_dir_entry_2 *) data1;
2006         top = data1 + len;
2007         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
2008                 de = de2;
2009         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
2010                                            (char *) de,
2011                                            blocksize);
2012 
2013         if (csum_size) {
2014                 t = EXT4_DIRENT_TAIL(data1, blocksize);
2015                 initialize_dirent_tail(t, blocksize);
2016         }
2017 
2018         /* Initialize the root; the dot dirents already exist */
2019         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
2020         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
2021                                            blocksize);
2022         memset (&root->info, 0, sizeof(root->info));
2023         root->info.info_length = sizeof(root->info);
2024         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
2025         entries = root->entries;
2026         dx_set_block(entries, 1);
2027         dx_set_count(entries, 1);
2028         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
2029 
2030         /* Initialize as for dx_probe */
2031         fname->hinfo.hash_version = root->info.hash_version;
2032         if (fname->hinfo.hash_version <= DX_HASH_TEA)
2033                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
2034         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
2035         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
2036 
2037         memset(frames, 0, sizeof(frames));
2038         frame = frames;
2039         frame->entries = entries;
2040         frame->at = entries;
2041         frame->bh = bh;
2042         bh = bh2;
2043 
2044         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2045         if (retval)
2046                 goto out_frames;        
2047         retval = ext4_handle_dirty_dirent_node(handle, dir, bh);
2048         if (retval)
2049                 goto out_frames;        
2050 
2051         de = do_split(handle,dir, &bh, frame, &fname->hinfo);
2052         if (IS_ERR(de)) {
2053                 retval = PTR_ERR(de);
2054                 goto out_frames;
2055         }
2056         dx_release(frames);
2057 
2058         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2059         brelse(bh);
2060         return retval;
2061 out_frames:
2062         /*
2063          * Even if the block split failed, we have to properly write
2064          * out all the changes we did so far. Otherwise we can end up
2065          * with corrupted filesystem.
2066          */
2067         ext4_mark_inode_dirty(handle, dir);
2068         dx_release(frames);
2069         return retval;
2070 }
2071 
2072 /*
2073  *      ext4_add_entry()
2074  *
2075  * adds a file entry to the specified directory, using the same
2076  * semantics as ext4_find_entry(). It returns NULL if it failed.
2077  *
2078  * NOTE!! The inode part of 'de' is left at 0 - which means you
2079  * may not sleep between calling this and putting something into
2080  * the entry, as someone else might have used it while you slept.
2081  */
2082 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2083                           struct inode *inode)
2084 {
2085         struct inode *dir = d_inode(dentry->d_parent);
2086         struct buffer_head *bh = NULL;
2087         struct ext4_dir_entry_2 *de;
2088         struct ext4_dir_entry_tail *t;
2089         struct super_block *sb;
2090         struct ext4_filename fname;
2091         int     retval;
2092         int     dx_fallback=0;
2093         unsigned blocksize;
2094         ext4_lblk_t block, blocks;
2095         int     csum_size = 0;
2096 
2097         if (ext4_has_metadata_csum(inode->i_sb))
2098                 csum_size = sizeof(struct ext4_dir_entry_tail);
2099 
2100         sb = dir->i_sb;
2101         blocksize = sb->s_blocksize;
2102         if (!dentry->d_name.len)
2103                 return -EINVAL;
2104 
2105         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2106         if (retval)
2107                 return retval;
2108 
2109         if (ext4_has_inline_data(dir)) {
2110                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2111                 if (retval < 0)
2112                         goto out;
2113                 if (retval == 1) {
2114                         retval = 0;
2115                         goto out;
2116                 }
2117         }
2118 
2119         if (is_dx(dir)) {
2120                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2121                 if (!retval || (retval != ERR_BAD_DX_DIR))
2122                         goto out;
2123                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2124                 dx_fallback++;
2125                 ext4_mark_inode_dirty(handle, dir);
2126         }
2127         blocks = dir->i_size >> sb->s_blocksize_bits;
2128         for (block = 0; block < blocks; block++) {
2129                 bh = ext4_read_dirblock(dir, block, DIRENT);
2130                 if (IS_ERR(bh)) {
2131                         retval = PTR_ERR(bh);
2132                         bh = NULL;
2133                         goto out;
2134                 }
2135                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2136                                            NULL, bh);
2137                 if (retval != -ENOSPC)
2138                         goto out;
2139 
2140                 if (blocks == 1 && !dx_fallback &&
2141                     ext4_has_feature_dir_index(sb)) {
2142                         retval = make_indexed_dir(handle, &fname, dir,
2143                                                   inode, bh);
2144                         bh = NULL; /* make_indexed_dir releases bh */
2145                         goto out;
2146                 }
2147                 brelse(bh);
2148         }
2149         bh = ext4_append(handle, dir, &block);
2150         if (IS_ERR(bh)) {
2151                 retval = PTR_ERR(bh);
2152                 bh = NULL;
2153                 goto out;
2154         }
2155         de = (struct ext4_dir_entry_2 *) bh->b_data;
2156         de->inode = 0;
2157         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2158 
2159         if (csum_size) {
2160                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2161                 initialize_dirent_tail(t, blocksize);
2162         }
2163 
2164         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2165 out:
2166         ext4_fname_free_filename(&fname);
2167         brelse(bh);
2168         if (retval == 0)
2169                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2170         return retval;
2171 }
2172 
2173 /*
2174  * Returns 0 for success, or a negative error value
2175  */
2176 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2177                              struct inode *dir, struct inode *inode)
2178 {
2179         struct dx_frame frames[2], *frame;
2180         struct dx_entry *entries, *at;
2181         struct buffer_head *bh;
2182         struct super_block *sb = dir->i_sb;
2183         struct ext4_dir_entry_2 *de;
2184         int err;
2185 
2186         frame = dx_probe(fname, dir, NULL, frames);
2187         if (IS_ERR(frame))
2188                 return PTR_ERR(frame);
2189         entries = frame->entries;
2190         at = frame->at;
2191         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2192         if (IS_ERR(bh)) {
2193                 err = PTR_ERR(bh);
2194                 bh = NULL;
2195                 goto cleanup;
2196         }
2197 
2198         BUFFER_TRACE(bh, "get_write_access");
2199         err = ext4_journal_get_write_access(handle, bh);
2200         if (err)
2201                 goto journal_error;
2202 
2203         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2204         if (err != -ENOSPC)
2205                 goto cleanup;
2206 
2207         /* Block full, should compress but for now just split */
2208         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2209                        dx_get_count(entries), dx_get_limit(entries)));
2210         /* Need to split index? */
2211         if (dx_get_count(entries) == dx_get_limit(entries)) {
2212                 ext4_lblk_t newblock;
2213                 unsigned icount = dx_get_count(entries);
2214                 int levels = frame - frames;
2215                 struct dx_entry *entries2;
2216                 struct dx_node *node2;
2217                 struct buffer_head *bh2;
2218 
2219                 if (levels && (dx_get_count(frames->entries) ==
2220                                dx_get_limit(frames->entries))) {
2221                         ext4_warning_inode(dir, "Directory index full!");
2222                         err = -ENOSPC;
2223                         goto cleanup;
2224                 }
2225                 bh2 = ext4_append(handle, dir, &newblock);
2226                 if (IS_ERR(bh2)) {
2227                         err = PTR_ERR(bh2);
2228                         goto cleanup;
2229                 }
2230                 node2 = (struct dx_node *)(bh2->b_data);
2231                 entries2 = node2->entries;
2232                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2233                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2234                                                            sb->s_blocksize);
2235                 BUFFER_TRACE(frame->bh, "get_write_access");
2236                 err = ext4_journal_get_write_access(handle, frame->bh);
2237                 if (err)
2238                         goto journal_error;
2239                 if (levels) {
2240                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2241                         unsigned hash2 = dx_get_hash(entries + icount1);
2242                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2243                                        icount1, icount2));
2244 
2245                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2246                         err = ext4_journal_get_write_access(handle,
2247                                                              frames[0].bh);
2248                         if (err)
2249                                 goto journal_error;
2250 
2251                         memcpy((char *) entries2, (char *) (entries + icount1),
2252                                icount2 * sizeof(struct dx_entry));
2253                         dx_set_count(entries, icount1);
2254                         dx_set_count(entries2, icount2);
2255                         dx_set_limit(entries2, dx_node_limit(dir));
2256 
2257                         /* Which index block gets the new entry? */
2258                         if (at - entries >= icount1) {
2259                                 frame->at = at = at - entries - icount1 + entries2;
2260                                 frame->entries = entries = entries2;
2261                                 swap(frame->bh, bh2);
2262                         }
2263                         dx_insert_block(frames + 0, hash2, newblock);
2264                         dxtrace(dx_show_index("node", frames[1].entries));
2265                         dxtrace(dx_show_index("node",
2266                                ((struct dx_node *) bh2->b_data)->entries));
2267                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2268                         if (err)
2269                                 goto journal_error;
2270                         brelse (bh2);
2271                 } else {
2272                         dxtrace(printk(KERN_DEBUG
2273                                        "Creating second level index...\n"));
2274                         memcpy((char *) entries2, (char *) entries,
2275                                icount * sizeof(struct dx_entry));
2276                         dx_set_limit(entries2, dx_node_limit(dir));
2277 
2278                         /* Set up root */
2279                         dx_set_count(entries, 1);
2280                         dx_set_block(entries + 0, newblock);
2281                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
2282 
2283                         /* Add new access path frame */
2284                         frame = frames + 1;
2285                         frame->at = at = at - entries + entries2;
2286                         frame->entries = entries = entries2;
2287                         frame->bh = bh2;
2288                         err = ext4_journal_get_write_access(handle,
2289                                                              frame->bh);
2290                         if (err)
2291                                 goto journal_error;
2292                 }
2293                 err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
2294                 if (err) {
2295                         ext4_std_error(inode->i_sb, err);
2296                         goto cleanup;
2297                 }
2298         }
2299         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2300         if (IS_ERR(de)) {
2301                 err = PTR_ERR(de);
2302                 goto cleanup;
2303         }
2304         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2305         goto cleanup;
2306 
2307 journal_error:
2308         ext4_std_error(dir->i_sb, err);
2309 cleanup:
2310         brelse(bh);
2311         dx_release(frames);
2312         return err;
2313 }
2314 
2315 /*
2316  * ext4_generic_delete_entry deletes a directory entry by merging it
2317  * with the previous entry
2318  */
2319 int ext4_generic_delete_entry(handle_t *handle,
2320                               struct inode *dir,
2321                               struct ext4_dir_entry_2 *de_del,
2322                               struct buffer_head *bh,
2323                               void *entry_buf,
2324                               int buf_size,
2325                               int csum_size)
2326 {
2327         struct ext4_dir_entry_2 *de, *pde;
2328         unsigned int blocksize = dir->i_sb->s_blocksize;
2329         int i;
2330 
2331         i = 0;
2332         pde = NULL;
2333         de = (struct ext4_dir_entry_2 *)entry_buf;
2334         while (i < buf_size - csum_size) {
2335                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2336                                          bh->b_data, bh->b_size, i))
2337                         return -EFSCORRUPTED;
2338                 if (de == de_del)  {
2339                         if (pde)
2340                                 pde->rec_len = ext4_rec_len_to_disk(
2341                                         ext4_rec_len_from_disk(pde->rec_len,
2342                                                                blocksize) +
2343                                         ext4_rec_len_from_disk(de->rec_len,
2344                                                                blocksize),
2345                                         blocksize);
2346                         else
2347                                 de->inode = 0;
2348                         dir->i_version++;
2349                         return 0;
2350                 }
2351                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2352                 pde = de;
2353                 de = ext4_next_entry(de, blocksize);
2354         }
2355         return -ENOENT;
2356 }
2357 
2358 static int ext4_delete_entry(handle_t *handle,
2359                              struct inode *dir,
2360                              struct ext4_dir_entry_2 *de_del,
2361                              struct buffer_head *bh)
2362 {
2363         int err, csum_size = 0;
2364 
2365         if (ext4_has_inline_data(dir)) {
2366                 int has_inline_data = 1;
2367                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2368                                                &has_inline_data);
2369                 if (has_inline_data)
2370                         return err;
2371         }
2372 
2373         if (ext4_has_metadata_csum(dir->i_sb))
2374                 csum_size = sizeof(struct ext4_dir_entry_tail);
2375 
2376         BUFFER_TRACE(bh, "get_write_access");
2377         err = ext4_journal_get_write_access(handle, bh);
2378         if (unlikely(err))
2379                 goto out;
2380 
2381         err = ext4_generic_delete_entry(handle, dir, de_del,
2382                                         bh, bh->b_data,
2383                                         dir->i_sb->s_blocksize, csum_size);
2384         if (err)
2385                 goto out;
2386 
2387         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2388         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2389         if (unlikely(err))
2390                 goto out;
2391 
2392         return 0;
2393 out:
2394         if (err != -ENOENT)
2395                 ext4_std_error(dir->i_sb, err);
2396         return err;
2397 }
2398 
2399 /*
2400  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
2401  * since this indicates that nlinks count was previously 1.
2402  */
2403 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2404 {
2405         inc_nlink(inode);
2406         if (is_dx(inode) && inode->i_nlink > 1) {
2407                 /* limit is 16-bit i_links_count */
2408                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
2409                         set_nlink(inode, 1);
2410                         ext4_set_feature_dir_nlink(inode->i_sb);
2411                 }
2412         }
2413 }
2414 
2415 /*
2416  * If a directory had nlink == 1, then we should let it be 1. This indicates
2417  * directory has >EXT4_LINK_MAX subdirs.
2418  */
2419 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2420 {
2421         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2422                 drop_nlink(inode);
2423 }
2424 
2425 
2426 static int ext4_add_nondir(handle_t *handle,
2427                 struct dentry *dentry, struct inode *inode)
2428 {
2429         int err = ext4_add_entry(handle, dentry, inode);
2430         if (!err) {
2431                 ext4_mark_inode_dirty(handle, inode);
2432                 unlock_new_inode(inode);
2433                 d_instantiate(dentry, inode);
2434                 return 0;
2435         }
2436         drop_nlink(inode);
2437         unlock_new_inode(inode);
2438         iput(inode);
2439         return err;
2440 }
2441 
2442 /*
2443  * By the time this is called, we already have created
2444  * the directory cache entry for the new file, but it
2445  * is so far negative - it has no inode.
2446  *
2447  * If the create succeeds, we fill in the inode information
2448  * with d_instantiate().
2449  */
2450 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2451                        bool excl)
2452 {
2453         handle_t *handle;
2454         struct inode *inode;
2455         int err, credits, retries = 0;
2456 
2457         err = dquot_initialize(dir);
2458         if (err)
2459                 return err;
2460 
2461         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2462                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2463 retry:
2464         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2465                                             NULL, EXT4_HT_DIR, credits);
2466         handle = ext4_journal_current_handle();
2467         err = PTR_ERR(inode);
2468         if (!IS_ERR(inode)) {
2469                 inode->i_op = &ext4_file_inode_operations;
2470                 inode->i_fop = &ext4_file_operations;
2471                 ext4_set_aops(inode);
2472                 err = ext4_add_nondir(handle, dentry, inode);
2473                 if (!err && IS_DIRSYNC(dir))
2474                         ext4_handle_sync(handle);
2475         }
2476         if (handle)
2477                 ext4_journal_stop(handle);
2478         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2479                 goto retry;
2480         return err;
2481 }
2482 
2483 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2484                       umode_t mode, dev_t rdev)
2485 {
2486         handle_t *handle;
2487         struct inode *inode;
2488         int err, credits, retries = 0;
2489 
2490         err = dquot_initialize(dir);
2491         if (err)
2492                 return err;
2493 
2494         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2495                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2496 retry:
2497         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2498                                             NULL, EXT4_HT_DIR, credits);
2499         handle = ext4_journal_current_handle();
2500         err = PTR_ERR(inode);
2501         if (!IS_ERR(inode)) {
2502                 init_special_inode(inode, inode->i_mode, rdev);
2503                 inode->i_op = &ext4_special_inode_operations;
2504                 err = ext4_add_nondir(handle, dentry, inode);
2505                 if (!err && IS_DIRSYNC(dir))
2506                         ext4_handle_sync(handle);
2507         }
2508         if (handle)
2509                 ext4_journal_stop(handle);
2510         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2511                 goto retry;
2512         return err;
2513 }
2514 
2515 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2516 {
2517         handle_t *handle;
2518         struct inode *inode;
2519         int err, retries = 0;
2520 
2521         err = dquot_initialize(dir);
2522         if (err)
2523                 return err;
2524 
2525 retry:
2526         inode = ext4_new_inode_start_handle(dir, mode,
2527                                             NULL, 0, NULL,
2528                                             EXT4_HT_DIR,
2529                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2530                           4 + EXT4_XATTR_TRANS_BLOCKS);
2531         handle = ext4_journal_current_handle();
2532         err = PTR_ERR(inode);
2533         if (!IS_ERR(inode)) {
2534                 inode->i_op = &ext4_file_inode_operations;
2535                 inode->i_fop = &ext4_file_operations;
2536                 ext4_set_aops(inode);
2537                 d_tmpfile(dentry, inode);
2538                 err = ext4_orphan_add(handle, inode);
2539                 if (err)
2540                         goto err_unlock_inode;
2541                 mark_inode_dirty(inode);
2542                 unlock_new_inode(inode);
2543         }
2544         if (handle)
2545                 ext4_journal_stop(handle);
2546         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2547                 goto retry;
2548         return err;
2549 err_unlock_inode:
2550         ext4_journal_stop(handle);
2551         unlock_new_inode(inode);
2552         return err;
2553 }
2554 
2555 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2556                           struct ext4_dir_entry_2 *de,
2557                           int blocksize, int csum_size,
2558                           unsigned int parent_ino, int dotdot_real_len)
2559 {
2560         de->inode = cpu_to_le32(inode->i_ino);
2561         de->name_len = 1;
2562         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2563                                            blocksize);
2564         strcpy(de->name, ".");
2565         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2566 
2567         de = ext4_next_entry(de, blocksize);
2568         de->inode = cpu_to_le32(parent_ino);
2569         de->name_len = 2;
2570         if (!dotdot_real_len)
2571                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2572                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2573                                         blocksize);
2574         else
2575                 de->rec_len = ext4_rec_len_to_disk(
2576                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2577         strcpy(de->name, "..");
2578         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2579 
2580         return ext4_next_entry(de, blocksize);
2581 }
2582 
2583 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2584                              struct inode *inode)
2585 {
2586         struct buffer_head *dir_block = NULL;
2587         struct ext4_dir_entry_2 *de;
2588         struct ext4_dir_entry_tail *t;
2589         ext4_lblk_t block = 0;
2590         unsigned int blocksize = dir->i_sb->s_blocksize;
2591         int csum_size = 0;
2592         int err;
2593 
2594         if (ext4_has_metadata_csum(dir->i_sb))
2595                 csum_size = sizeof(struct ext4_dir_entry_tail);
2596 
2597         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2598                 err = ext4_try_create_inline_dir(handle, dir, inode);
2599                 if (err < 0 && err != -ENOSPC)
2600                         goto out;
2601                 if (!err)
2602                         goto out;
2603         }
2604 
2605         inode->i_size = 0;
2606         dir_block = ext4_append(handle, inode, &block);
2607         if (IS_ERR(dir_block))
2608                 return PTR_ERR(dir_block);
2609         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2610         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2611         set_nlink(inode, 2);
2612         if (csum_size) {
2613                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2614                 initialize_dirent_tail(t, blocksize);
2615         }
2616 
2617         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2618         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2619         if (err)
2620                 goto out;
2621         set_buffer_verified(dir_block);
2622 out:
2623         brelse(dir_block);
2624         return err;
2625 }
2626 
2627 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2628 {
2629         handle_t *handle;
2630         struct inode *inode;
2631         int err, credits, retries = 0;
2632 
2633         if (EXT4_DIR_LINK_MAX(dir))
2634                 return -EMLINK;
2635 
2636         err = dquot_initialize(dir);
2637         if (err)
2638                 return err;
2639 
2640         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2641                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2642 retry:
2643         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2644                                             &dentry->d_name,
2645                                             0, NULL, EXT4_HT_DIR, credits);
2646         handle = ext4_journal_current_handle();
2647         err = PTR_ERR(inode);
2648         if (IS_ERR(inode))
2649                 goto out_stop;
2650 
2651         inode->i_op = &ext4_dir_inode_operations;
2652         inode->i_fop = &ext4_dir_operations;
2653         err = ext4_init_new_dir(handle, dir, inode);
2654         if (err)
2655                 goto out_clear_inode;
2656         err = ext4_mark_inode_dirty(handle, inode);
2657         if (!err)
2658                 err = ext4_add_entry(handle, dentry, inode);
2659         if (err) {
2660 out_clear_inode:
2661                 clear_nlink(inode);
2662                 unlock_new_inode(inode);
2663                 ext4_mark_inode_dirty(handle, inode);
2664                 iput(inode);
2665                 goto out_stop;
2666         }
2667         ext4_inc_count(handle, dir);
2668         ext4_update_dx_flag(dir);
2669         err = ext4_mark_inode_dirty(handle, dir);
2670         if (err)
2671                 goto out_clear_inode;
2672         unlock_new_inode(inode);
2673         d_instantiate(dentry, inode);
2674         if (IS_DIRSYNC(dir))
2675                 ext4_handle_sync(handle);
2676 
2677 out_stop:
2678         if (handle)
2679                 ext4_journal_stop(handle);
2680         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2681                 goto retry;
2682         return err;
2683 }
2684 
2685 /*
2686  * routine to check that the specified directory is empty (for rmdir)
2687  */
2688 int ext4_empty_dir(struct inode *inode)
2689 {
2690         unsigned int offset;
2691         struct buffer_head *bh;
2692         struct ext4_dir_entry_2 *de, *de1;
2693         struct super_block *sb;
2694         int err = 0;
2695 
2696         if (ext4_has_inline_data(inode)) {
2697                 int has_inline_data = 1;
2698 
2699                 err = empty_inline_dir(inode, &has_inline_data);
2700                 if (has_inline_data)
2701                         return err;
2702         }
2703 
2704         sb = inode->i_sb;
2705         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2706                 EXT4_ERROR_INODE(inode, "invalid size");
2707                 return 1;
2708         }
2709         bh = ext4_read_dirblock(inode, 0, EITHER);
2710         if (IS_ERR(bh))
2711                 return 1;
2712 
2713         de = (struct ext4_dir_entry_2 *) bh->b_data;
2714         de1 = ext4_next_entry(de, sb->s_blocksize);
2715         if (le32_to_cpu(de->inode) != inode->i_ino ||
2716                         le32_to_cpu(de1->inode) == 0 ||
2717                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2718                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2719                 brelse(bh);
2720                 return 1;
2721         }
2722         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2723                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2724         de = ext4_next_entry(de1, sb->s_blocksize);
2725         while (offset < inode->i_size) {
2726                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2727                         unsigned int lblock;
2728                         err = 0;
2729                         brelse(bh);
2730                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2731                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2732                         if (IS_ERR(bh))
2733                                 return 1;
2734                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2735                 }
2736                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2737                                          bh->b_data, bh->b_size, offset)) {
2738                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2739                                                          sb->s_blocksize);
2740                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2741                         continue;
2742                 }
2743                 if (le32_to_cpu(de->inode)) {
2744                         brelse(bh);
2745                         return 0;
2746                 }
2747                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2748                 de = ext4_next_entry(de, sb->s_blocksize);
2749         }
2750         brelse(bh);
2751         return 1;
2752 }
2753 
2754 /*
2755  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2756  * such inodes, starting at the superblock, in case we crash before the
2757  * file is closed/deleted, or in case the inode truncate spans multiple
2758  * transactions and the last transaction is not recovered after a crash.
2759  *
2760  * At filesystem recovery time, we walk this list deleting unlinked
2761  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2762  *
2763  * Orphan list manipulation functions must be called under i_mutex unless
2764  * we are just creating the inode or deleting it.
2765  */
2766 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2767 {
2768         struct super_block *sb = inode->i_sb;
2769         struct ext4_sb_info *sbi = EXT4_SB(sb);
2770         struct ext4_iloc iloc;
2771         int err = 0, rc;
2772         bool dirty = false;
2773 
2774         if (!sbi->s_journal || is_bad_inode(inode))
2775                 return 0;
2776 
2777         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2778                      !inode_is_locked(inode));
2779         /*
2780          * Exit early if inode already is on orphan list. This is a big speedup
2781          * since we don't have to contend on the global s_orphan_lock.
2782          */
2783         if (!list_empty(&EXT4_I(inode)->i_orphan))
2784                 return 0;
2785 
2786         /*
2787          * Orphan handling is only valid for files with data blocks
2788          * being truncated, or files being unlinked. Note that we either
2789          * hold i_mutex, or the inode can not be referenced from outside,
2790          * so i_nlink should not be bumped due to race
2791          */
2792         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2793                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2794 
2795         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2796         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2797         if (err)
2798                 goto out;
2799 
2800         err = ext4_reserve_inode_write(handle, inode, &iloc);
2801         if (err)
2802                 goto out;
2803 
2804         mutex_lock(&sbi->s_orphan_lock);
2805         /*
2806          * Due to previous errors inode may be already a part of on-disk
2807          * orphan list. If so skip on-disk list modification.
2808          */
2809         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2810             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2811                 /* Insert this inode at the head of the on-disk orphan list */
2812                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2813                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2814                 dirty = true;
2815         }
2816         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2817         mutex_unlock(&sbi->s_orphan_lock);
2818 
2819         if (dirty) {
2820                 err = ext4_handle_dirty_super(handle, sb);
2821                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2822                 if (!err)
2823                         err = rc;
2824                 if (err) {
2825                         /*
2826                          * We have to remove inode from in-memory list if
2827                          * addition to on disk orphan list failed. Stray orphan
2828                          * list entries can cause panics at unmount time.
2829                          */
2830                         mutex_lock(&sbi->s_orphan_lock);
2831                         list_del_init(&EXT4_I(inode)->i_orphan);
2832                         mutex_unlock(&sbi->s_orphan_lock);
2833                 }
2834         }
2835         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2836         jbd_debug(4, "orphan inode %lu will point to %d\n",
2837                         inode->i_ino, NEXT_ORPHAN(inode));
2838 out:
2839         ext4_std_error(sb, err);
2840         return err;
2841 }
2842 
2843 /*
2844  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2845  * of such inodes stored on disk, because it is finally being cleaned up.
2846  */
2847 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2848 {
2849         struct list_head *prev;
2850         struct ext4_inode_info *ei = EXT4_I(inode);
2851         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2852         __u32 ino_next;
2853         struct ext4_iloc iloc;
2854         int err = 0;
2855 
2856         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2857                 return 0;
2858 
2859         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2860                      !inode_is_locked(inode));
2861         /* Do this quick check before taking global s_orphan_lock. */
2862         if (list_empty(&ei->i_orphan))
2863                 return 0;
2864 
2865         if (handle) {
2866                 /* Grab inode buffer early before taking global s_orphan_lock */
2867                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2868         }
2869 
2870         mutex_lock(&sbi->s_orphan_lock);
2871         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2872 
2873         prev = ei->i_orphan.prev;
2874         list_del_init(&ei->i_orphan);
2875 
2876         /* If we're on an error path, we may not have a valid
2877          * transaction handle with which to update the orphan list on
2878          * disk, but we still need to remove the inode from the linked
2879          * list in memory. */
2880         if (!handle || err) {
2881                 mutex_unlock(&sbi->s_orphan_lock);
2882                 goto out_err;
2883         }
2884 
2885         ino_next = NEXT_ORPHAN(inode);
2886         if (prev == &sbi->s_orphan) {
2887                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2888                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2889                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2890                 if (err) {
2891                         mutex_unlock(&sbi->s_orphan_lock);
2892                         goto out_brelse;
2893                 }
2894                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2895                 mutex_unlock(&sbi->s_orphan_lock);
2896                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2897         } else {
2898                 struct ext4_iloc iloc2;
2899                 struct inode *i_prev =
2900                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2901 
2902                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2903                           i_prev->i_ino, ino_next);
2904                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2905                 if (err) {
2906                         mutex_unlock(&sbi->s_orphan_lock);
2907                         goto out_brelse;
2908                 }
2909                 NEXT_ORPHAN(i_prev) = ino_next;
2910                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2911                 mutex_unlock(&sbi->s_orphan_lock);
2912         }
2913         if (err)
2914                 goto out_brelse;
2915         NEXT_ORPHAN(inode) = 0;
2916         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2917 out_err:
2918         ext4_std_error(inode->i_sb, err);
2919         return err;
2920 
2921 out_brelse:
2922         brelse(iloc.bh);
2923         goto out_err;
2924 }
2925 
2926 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2927 {
2928         int retval;
2929         struct inode *inode;
2930         struct buffer_head *bh;
2931         struct ext4_dir_entry_2 *de;
2932         handle_t *handle = NULL;
2933 
2934         /* Initialize quotas before so that eventual writes go in
2935          * separate transaction */
2936         retval = dquot_initialize(dir);
2937         if (retval)
2938                 return retval;
2939         retval = dquot_initialize(d_inode(dentry));
2940         if (retval)
2941                 return retval;
2942 
2943         retval = -ENOENT;
2944         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2945         if (IS_ERR(bh))
2946                 return PTR_ERR(bh);
2947         if (!bh)
2948                 goto end_rmdir;
2949 
2950         inode = d_inode(dentry);
2951 
2952         retval = -EFSCORRUPTED;
2953         if (le32_to_cpu(de->inode) != inode->i_ino)
2954                 goto end_rmdir;
2955 
2956         retval = -ENOTEMPTY;
2957         if (!ext4_empty_dir(inode))
2958                 goto end_rmdir;
2959 
2960         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2961                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2962         if (IS_ERR(handle)) {
2963                 retval = PTR_ERR(handle);
2964                 handle = NULL;
2965                 goto end_rmdir;
2966         }
2967 
2968         if (IS_DIRSYNC(dir))
2969                 ext4_handle_sync(handle);
2970 
2971         retval = ext4_delete_entry(handle, dir, de, bh);
2972         if (retval)
2973                 goto end_rmdir;
2974         if (!EXT4_DIR_LINK_EMPTY(inode))
2975                 ext4_warning_inode(inode,
2976                              "empty directory '%.*s' has too many links (%u)",
2977                              dentry->d_name.len, dentry->d_name.name,
2978                              inode->i_nlink);
2979         inode->i_version++;
2980         clear_nlink(inode);
2981         /* There's no need to set i_disksize: the fact that i_nlink is
2982          * zero will ensure that the right thing happens during any
2983          * recovery. */
2984         inode->i_size = 0;
2985         ext4_orphan_add(handle, inode);
2986         inode->i_ctime = dir->i_ctime = dir->i_mtime = ext4_current_time(inode);
2987         ext4_mark_inode_dirty(handle, inode);
2988         ext4_dec_count(handle, dir);
2989         ext4_update_dx_flag(dir);
2990         ext4_mark_inode_dirty(handle, dir);
2991 
2992 end_rmdir:
2993         brelse(bh);
2994         if (handle)
2995                 ext4_journal_stop(handle);
2996         return retval;
2997 }
2998 
2999 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
3000 {
3001         int retval;
3002         struct inode *inode;
3003         struct buffer_head *bh;
3004         struct ext4_dir_entry_2 *de;
3005         handle_t *handle = NULL;
3006 
3007         trace_ext4_unlink_enter(dir, dentry);
3008         /* Initialize quotas before so that eventual writes go
3009          * in separate transaction */
3010         retval = dquot_initialize(dir);
3011         if (retval)
3012                 return retval;
3013         retval = dquot_initialize(d_inode(dentry));
3014         if (retval)
3015                 return retval;
3016 
3017         retval = -ENOENT;
3018         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3019         if (IS_ERR(bh))
3020                 return PTR_ERR(bh);
3021         if (!bh)
3022                 goto end_unlink;
3023 
3024         inode = d_inode(dentry);
3025 
3026         retval = -EFSCORRUPTED;
3027         if (le32_to_cpu(de->inode) != inode->i_ino)
3028                 goto end_unlink;
3029 
3030         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3031                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3032         if (IS_ERR(handle)) {
3033                 retval = PTR_ERR(handle);
3034                 handle = NULL;
3035                 goto end_unlink;
3036         }
3037 
3038         if (IS_DIRSYNC(dir))
3039                 ext4_handle_sync(handle);
3040 
3041         if (inode->i_nlink == 0) {
3042                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3043                                    dentry->d_name.len, dentry->d_name.name);
3044                 set_nlink(inode, 1);
3045         }
3046         retval = ext4_delete_entry(handle, dir, de, bh);
3047         if (retval)
3048                 goto end_unlink;
3049         dir->i_ctime = dir->i_mtime = ext4_current_time(dir);
3050         ext4_update_dx_flag(dir);
3051         ext4_mark_inode_dirty(handle, dir);
3052         drop_nlink(inode);
3053         if (!inode->i_nlink)
3054                 ext4_orphan_add(handle, inode);
3055         inode->i_ctime = ext4_current_time(inode);
3056         ext4_mark_inode_dirty(handle, inode);
3057 
3058 end_unlink:
3059         brelse(bh);
3060         if (handle)
3061                 ext4_journal_stop(handle);
3062         trace_ext4_unlink_exit(dentry, retval);
3063         return retval;
3064 }
3065 
3066 static int ext4_symlink(struct inode *dir,
3067                         struct dentry *dentry, const char *symname)
3068 {
3069         handle_t *handle;
3070         struct inode *inode;
3071         int err, len = strlen(symname);
3072         int credits;
3073         bool encryption_required;
3074         struct ext4_str disk_link;
3075         struct ext4_encrypted_symlink_data *sd = NULL;
3076 
3077         disk_link.len = len + 1;
3078         disk_link.name = (char *) symname;
3079 
3080         encryption_required = (ext4_encrypted_inode(dir) ||
3081                                DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
3082         if (encryption_required) {
3083                 err = ext4_get_encryption_info(dir);
3084                 if (err)
3085                         return err;
3086                 if (ext4_encryption_info(dir) == NULL)
3087                         return -EPERM;
3088                 disk_link.len = (ext4_fname_encrypted_size(dir, len) +
3089                                  sizeof(struct ext4_encrypted_symlink_data));
3090                 sd = kzalloc(disk_link.len, GFP_KERNEL);
3091                 if (!sd)
3092                         return -ENOMEM;
3093         }
3094 
3095         if (disk_link.len > dir->i_sb->s_blocksize) {
3096                 err = -ENAMETOOLONG;
3097                 goto err_free_sd;
3098         }
3099 
3100         err = dquot_initialize(dir);
3101         if (err)
3102                 goto err_free_sd;
3103 
3104         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3105                 /*
3106                  * For non-fast symlinks, we just allocate inode and put it on
3107                  * orphan list in the first transaction => we need bitmap,
3108                  * group descriptor, sb, inode block, quota blocks, and
3109                  * possibly selinux xattr blocks.
3110                  */
3111                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3112                           EXT4_XATTR_TRANS_BLOCKS;
3113         } else {
3114                 /*
3115                  * Fast symlink. We have to add entry to directory
3116                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3117                  * allocate new inode (bitmap, group descriptor, inode block,
3118                  * quota blocks, sb is already counted in previous macros).
3119                  */
3120                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3121                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3122         }
3123 
3124         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3125                                             &dentry->d_name, 0, NULL,
3126                                             EXT4_HT_DIR, credits);
3127         handle = ext4_journal_current_handle();
3128         if (IS_ERR(inode)) {
3129                 if (handle)
3130                         ext4_journal_stop(handle);
3131                 err = PTR_ERR(inode);
3132                 goto err_free_sd;
3133         }
3134 
3135         if (encryption_required) {
3136                 struct qstr istr;
3137                 struct ext4_str ostr;
3138 
3139                 istr.name = (const unsigned char *) symname;
3140                 istr.len = len;
3141                 ostr.name = sd->encrypted_path;
3142                 ostr.len = disk_link.len;
3143                 err = ext4_fname_usr_to_disk(inode, &istr, &ostr);
3144                 if (err < 0)
3145                         goto err_drop_inode;
3146                 sd->len = cpu_to_le16(ostr.len);
3147                 disk_link.name = (char *) sd;
3148                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3149         }
3150 
3151         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3152                 if (!encryption_required)
3153                         inode->i_op = &ext4_symlink_inode_operations;
3154                 inode_nohighmem(inode);
3155                 ext4_set_aops(inode);
3156                 /*
3157                  * We cannot call page_symlink() with transaction started
3158                  * because it calls into ext4_write_begin() which can wait
3159                  * for transaction commit if we are running out of space
3160                  * and thus we deadlock. So we have to stop transaction now
3161                  * and restart it when symlink contents is written.
3162                  * 
3163                  * To keep fs consistent in case of crash, we have to put inode
3164                  * to orphan list in the mean time.
3165                  */
3166                 drop_nlink(inode);
3167                 err = ext4_orphan_add(handle, inode);
3168                 ext4_journal_stop(handle);
3169                 handle = NULL;
3170                 if (err)
3171                         goto err_drop_inode;
3172                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3173                 if (err)
3174                         goto err_drop_inode;
3175                 /*
3176                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3177                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3178                  */
3179                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3180                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3181                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3182                 if (IS_ERR(handle)) {
3183                         err = PTR_ERR(handle);
3184                         handle = NULL;
3185                         goto err_drop_inode;
3186                 }
3187                 set_nlink(inode, 1);
3188                 err = ext4_orphan_del(handle, inode);
3189                 if (err)
3190                         goto err_drop_inode;
3191         } else {
3192                 /* clear the extent format for fast symlink */
3193                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3194                 if (!encryption_required) {
3195                         inode->i_op = &ext4_fast_symlink_inode_operations;
3196                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3197                 }
3198                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3199                        disk_link.len);
3200                 inode->i_size = disk_link.len - 1;
3201         }
3202         EXT4_I(inode)->i_disksize = inode->i_size;
3203         err = ext4_add_nondir(handle, dentry, inode);
3204         if (!err && IS_DIRSYNC(dir))
3205                 ext4_handle_sync(handle);
3206 
3207         if (handle)
3208                 ext4_journal_stop(handle);
3209         kfree(sd);
3210         return err;
3211 err_drop_inode:
3212         if (handle)
3213                 ext4_journal_stop(handle);
3214         clear_nlink(inode);
3215         unlock_new_inode(inode);
3216         iput(inode);
3217 err_free_sd:
3218         kfree(sd);
3219         return err;
3220 }
3221 
3222 static int ext4_link(struct dentry *old_dentry,
3223                      struct inode *dir, struct dentry *dentry)
3224 {
3225         handle_t *handle;
3226         struct inode *inode = d_inode(old_dentry);
3227         int err, retries = 0;
3228 
3229         if (inode->i_nlink >= EXT4_LINK_MAX)
3230                 return -EMLINK;
3231         if (ext4_encrypted_inode(dir) &&
3232             !ext4_is_child_context_consistent_with_parent(dir, inode))
3233                 return -EPERM;
3234 
3235        if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3236            (!projid_eq(EXT4_I(dir)->i_projid,
3237                        EXT4_I(old_dentry->d_inode)->i_projid)))
3238                 return -EXDEV;
3239 
3240         err = dquot_initialize(dir);
3241         if (err)
3242                 return err;
3243 
3244 retry:
3245         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3246                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3247                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3248         if (IS_ERR(handle))
3249                 return PTR_ERR(handle);
3250 
3251         if (IS_DIRSYNC(dir))
3252                 ext4_handle_sync(handle);
3253 
3254         inode->i_ctime = ext4_current_time(inode);
3255         ext4_inc_count(handle, inode);
3256         ihold(inode);
3257 
3258         err = ext4_add_entry(handle, dentry, inode);
3259         if (!err) {
3260                 ext4_mark_inode_dirty(handle, inode);
3261                 /* this can happen only for tmpfile being
3262                  * linked the first time
3263                  */
3264                 if (inode->i_nlink == 1)
3265                         ext4_orphan_del(handle, inode);
3266                 d_instantiate(dentry, inode);
3267         } else {
3268                 drop_nlink(inode);
3269                 iput(inode);
3270         }
3271         ext4_journal_stop(handle);
3272         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3273                 goto retry;
3274         return err;
3275 }
3276 
3277 
3278 /*
3279  * Try to find buffer head where contains the parent block.
3280  * It should be the inode block if it is inlined or the 1st block
3281  * if it is a normal dir.
3282  */
3283 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3284                                         struct inode *inode,
3285                                         int *retval,
3286                                         struct ext4_dir_entry_2 **parent_de,
3287                                         int *inlined)
3288 {
3289         struct buffer_head *bh;
3290 
3291         if (!ext4_has_inline_data(inode)) {
3292                 bh = ext4_read_dirblock(inode, 0, EITHER);
3293                 if (IS_ERR(bh)) {
3294                         *retval = PTR_ERR(bh);
3295                         return NULL;
3296                 }
3297                 *parent_de = ext4_next_entry(
3298                                         (struct ext4_dir_entry_2 *)bh->b_data,
3299                                         inode->i_sb->s_blocksize);
3300                 return bh;
3301         }
3302 
3303         *inlined = 1;
3304         return ext4_get_first_inline_block(inode, parent_de, retval);
3305 }
3306 
3307 struct ext4_renament {
3308         struct inode *dir;
3309         struct dentry *dentry;
3310         struct inode *inode;
3311         bool is_dir;
3312         int dir_nlink_delta;
3313 
3314         /* entry for "dentry" */
3315         struct buffer_head *bh;
3316         struct ext4_dir_entry_2 *de;
3317         int inlined;
3318 
3319         /* entry for ".." in inode if it's a directory */
3320         struct buffer_head *dir_bh;
3321         struct ext4_dir_entry_2 *parent_de;
3322         int dir_inlined;
3323 };
3324 
3325 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3326 {
3327         int retval;
3328 
3329         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3330                                               &retval, &ent->parent_de,
3331                                               &ent->dir_inlined);
3332         if (!ent->dir_bh)
3333                 return retval;
3334         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3335                 return -EFSCORRUPTED;
3336         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3337         return ext4_journal_get_write_access(handle, ent->dir_bh);
3338 }
3339 
3340 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3341                                   unsigned dir_ino)
3342 {
3343         int retval;
3344 
3345         ent->parent_de->inode = cpu_to_le32(dir_ino);
3346         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3347         if (!ent->dir_inlined) {
3348                 if (is_dx(ent->inode)) {
3349                         retval = ext4_handle_dirty_dx_node(handle,
3350                                                            ent->inode,
3351                                                            ent->dir_bh);
3352                 } else {
3353                         retval = ext4_handle_dirty_dirent_node(handle,
3354                                                                ent->inode,
3355                                                                ent->dir_bh);
3356                 }
3357         } else {
3358                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3359         }
3360         if (retval) {
3361                 ext4_std_error(ent->dir->i_sb, retval);
3362                 return retval;
3363         }
3364         return 0;
3365 }
3366 
3367 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3368                        unsigned ino, unsigned file_type)
3369 {
3370         int retval;
3371 
3372         BUFFER_TRACE(ent->bh, "get write access");
3373         retval = ext4_journal_get_write_access(handle, ent->bh);
3374         if (retval)
3375                 return retval;
3376         ent->de->inode = cpu_to_le32(ino);
3377         if (ext4_has_feature_filetype(ent->dir->i_sb))
3378                 ent->de->file_type = file_type;
3379         ent->dir->i_version++;
3380         ent->dir->i_ctime = ent->dir->i_mtime =
3381                 ext4_current_time(ent->dir);
3382         ext4_mark_inode_dirty(handle, ent->dir);
3383         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3384         if (!ent->inlined) {
3385                 retval = ext4_handle_dirty_dirent_node(handle,
3386                                                        ent->dir, ent->bh);
3387                 if (unlikely(retval)) {
3388                         ext4_std_error(ent->dir->i_sb, retval);
3389                         return retval;
3390                 }
3391         }
3392         brelse(ent->bh);
3393         ent->bh = NULL;
3394 
3395         return 0;
3396 }
3397 
3398 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3399                                   const struct qstr *d_name)
3400 {
3401         int retval = -ENOENT;
3402         struct buffer_head *bh;
3403         struct ext4_dir_entry_2 *de;
3404 
3405         bh = ext4_find_entry(dir, d_name, &de, NULL);
3406         if (IS_ERR(bh))
3407                 return PTR_ERR(bh);
3408         if (bh) {
3409                 retval = ext4_delete_entry(handle, dir, de, bh);
3410                 brelse(bh);
3411         }
3412         return retval;
3413 }
3414 
3415 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3416                                int force_reread)
3417 {
3418         int retval;
3419         /*
3420          * ent->de could have moved from under us during htree split, so make
3421          * sure that we are deleting the right entry.  We might also be pointing
3422          * to a stale entry in the unused part of ent->bh so just checking inum
3423          * and the name isn't enough.
3424          */
3425         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3426             ent->de->name_len != ent->dentry->d_name.len ||
3427             strncmp(ent->de->name, ent->dentry->d_name.name,
3428                     ent->de->name_len) ||
3429             force_reread) {
3430                 retval = ext4_find_delete_entry(handle, ent->dir,
3431                                                 &ent->dentry->d_name);
3432         } else {
3433                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3434                 if (retval == -ENOENT) {
3435                         retval = ext4_find_delete_entry(handle, ent->dir,
3436                                                         &ent->dentry->d_name);
3437                 }
3438         }
3439 
3440         if (retval) {
3441                 ext4_warning_inode(ent->dir,
3442                                    "Deleting old file: nlink %d, error=%d",
3443                                    ent->dir->i_nlink, retval);
3444         }
3445 }
3446 
3447 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3448 {
3449         if (ent->dir_nlink_delta) {
3450                 if (ent->dir_nlink_delta == -1)
3451                         ext4_dec_count(handle, ent->dir);
3452                 else
3453                         ext4_inc_count(handle, ent->dir);
3454                 ext4_mark_inode_dirty(handle, ent->dir);
3455         }
3456 }
3457 
3458 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3459                                               int credits, handle_t **h)
3460 {
3461         struct inode *wh;
3462         handle_t *handle;
3463         int retries = 0;
3464 
3465         /*
3466          * for inode block, sb block, group summaries,
3467          * and inode bitmap
3468          */
3469         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3470                     EXT4_XATTR_TRANS_BLOCKS + 4);
3471 retry:
3472         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3473                                          &ent->dentry->d_name, 0, NULL,
3474                                          EXT4_HT_DIR, credits);
3475 
3476         handle = ext4_journal_current_handle();
3477         if (IS_ERR(wh)) {
3478                 if (handle)
3479                         ext4_journal_stop(handle);
3480                 if (PTR_ERR(wh) == -ENOSPC &&
3481                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3482                         goto retry;
3483         } else {
3484                 *h = handle;
3485                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3486                 wh->i_op = &ext4_special_inode_operations;
3487         }
3488         return wh;
3489 }
3490 
3491 /*
3492  * Anybody can rename anything with this: the permission checks are left to the
3493  * higher-level routines.
3494  *
3495  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3496  * while new_{dentry,inode) refers to the destination dentry/inode
3497  * This comes from rename(const char *oldpath, const char *newpath)
3498  */
3499 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3500                        struct inode *new_dir, struct dentry *new_dentry,
3501                        unsigned int flags)
3502 {
3503         handle_t *handle = NULL;
3504         struct ext4_renament old = {
3505                 .dir = old_dir,
3506                 .dentry = old_dentry,
3507                 .inode = d_inode(old_dentry),
3508         };
3509         struct ext4_renament new = {
3510                 .dir = new_dir,
3511                 .dentry = new_dentry,
3512                 .inode = d_inode(new_dentry),
3513         };
3514         int force_reread;
3515         int retval;
3516         struct inode *whiteout = NULL;
3517         int credits;
3518         u8 old_file_type;
3519 
3520         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3521             (!projid_eq(EXT4_I(new_dir)->i_projid,
3522                         EXT4_I(old_dentry->d_inode)->i_projid)))
3523                 return -EXDEV;
3524 
3525         retval = dquot_initialize(old.dir);
3526         if (retval)
3527                 return retval;
3528         retval = dquot_initialize(new.dir);
3529         if (retval)
3530                 return retval;
3531 
3532         /* Initialize quotas before so that eventual writes go
3533          * in separate transaction */
3534         if (new.inode) {
3535                 retval = dquot_initialize(new.inode);
3536                 if (retval)
3537                         return retval;
3538         }
3539 
3540         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3541         if (IS_ERR(old.bh))
3542                 return PTR_ERR(old.bh);
3543         /*
3544          *  Check for inode number is _not_ due to possible IO errors.
3545          *  We might rmdir the source, keep it as pwd of some process
3546          *  and merrily kill the link to whatever was created under the
3547          *  same name. Goodbye sticky bit ;-<
3548          */
3549         retval = -ENOENT;
3550         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3551                 goto end_rename;
3552 
3553         if ((old.dir != new.dir) &&
3554             ext4_encrypted_inode(new.dir) &&
3555             !ext4_is_child_context_consistent_with_parent(new.dir,
3556                                                           old.inode)) {
3557                 retval = -EPERM;
3558                 goto end_rename;
3559         }
3560 
3561         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3562                                  &new.de, &new.inlined);
3563         if (IS_ERR(new.bh)) {
3564                 retval = PTR_ERR(new.bh);
3565                 new.bh = NULL;
3566                 goto end_rename;
3567         }
3568         if (new.bh) {
3569                 if (!new.inode) {
3570                         brelse(new.bh);
3571                         new.bh = NULL;
3572                 }
3573         }
3574         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3575                 ext4_alloc_da_blocks(old.inode);
3576 
3577         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3578                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3579         if (!(flags & RENAME_WHITEOUT)) {
3580                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3581                 if (IS_ERR(handle)) {
3582                         retval = PTR_ERR(handle);
3583                         handle = NULL;
3584                         goto end_rename;
3585                 }
3586         } else {
3587                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3588                 if (IS_ERR(whiteout)) {
3589                         retval = PTR_ERR(whiteout);
3590                         whiteout = NULL;
3591                         goto end_rename;
3592                 }
3593         }
3594 
3595         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3596                 ext4_handle_sync(handle);
3597 
3598         if (S_ISDIR(old.inode->i_mode)) {
3599                 if (new.inode) {
3600                         retval = -ENOTEMPTY;
3601                         if (!ext4_empty_dir(new.inode))
3602                                 goto end_rename;
3603                 } else {
3604                         retval = -EMLINK;
3605                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3606                                 goto end_rename;
3607                 }
3608                 retval = ext4_rename_dir_prepare(handle, &old);
3609                 if (retval)
3610                         goto end_rename;
3611         }
3612         /*
3613          * If we're renaming a file within an inline_data dir and adding or
3614          * setting the new dirent causes a conversion from inline_data to
3615          * extents/blockmap, we need to force the dirent delete code to
3616          * re-read the directory, or else we end up trying to delete a dirent
3617          * from what is now the extent tree root (or a block map).
3618          */
3619         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3620                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3621 
3622         old_file_type = old.de->file_type;
3623         if (whiteout) {
3624                 /*
3625                  * Do this before adding a new entry, so the old entry is sure
3626                  * to be still pointing to the valid old entry.
3627                  */
3628                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3629                                      EXT4_FT_CHRDEV);
3630                 if (retval)
3631                         goto end_rename;
3632                 ext4_mark_inode_dirty(handle, whiteout);
3633         }
3634         if (!new.bh) {
3635                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3636                 if (retval)
3637                         goto end_rename;
3638         } else {
3639                 retval = ext4_setent(handle, &new,
3640                                      old.inode->i_ino, old_file_type);
3641                 if (retval)
3642                         goto end_rename;
3643         }
3644         if (force_reread)
3645                 force_reread = !ext4_test_inode_flag(new.dir,
3646                                                      EXT4_INODE_INLINE_DATA);
3647 
3648         /*
3649          * Like most other Unix systems, set the ctime for inodes on a
3650          * rename.
3651          */
3652         old.inode->i_ctime = ext4_current_time(old.inode);
3653         ext4_mark_inode_dirty(handle, old.inode);
3654 
3655         if (!whiteout) {
3656                 /*
3657                  * ok, that's it
3658                  */
3659                 ext4_rename_delete(handle, &old, force_reread);
3660         }
3661 
3662         if (new.inode) {
3663                 ext4_dec_count(handle, new.inode);
3664                 new.inode->i_ctime = ext4_current_time(new.inode);
3665         }
3666         old.dir->i_ctime = old.dir->i_mtime = ext4_current_time(old.dir);
3667         ext4_update_dx_flag(old.dir);
3668         if (old.dir_bh) {
3669                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3670                 if (retval)
3671                         goto end_rename;
3672 
3673                 ext4_dec_count(handle, old.dir);
3674                 if (new.inode) {
3675                         /* checked ext4_empty_dir above, can't have another
3676                          * parent, ext4_dec_count() won't work for many-linked
3677                          * dirs */
3678                         clear_nlink(new.inode);
3679                 } else {
3680                         ext4_inc_count(handle, new.dir);
3681                         ext4_update_dx_flag(new.dir);
3682                         ext4_mark_inode_dirty(handle, new.dir);
3683                 }
3684         }
3685         ext4_mark_inode_dirty(handle, old.dir);
3686         if (new.inode) {
3687                 ext4_mark_inode_dirty(handle, new.inode);
3688                 if (!new.inode->i_nlink)
3689                         ext4_orphan_add(handle, new.inode);
3690         }
3691         retval = 0;
3692 
3693 end_rename:
3694         brelse(old.dir_bh);
3695         brelse(old.bh);
3696         brelse(new.bh);
3697         if (whiteout) {
3698                 if (retval)
3699                         drop_nlink(whiteout);
3700                 unlock_new_inode(whiteout);
3701                 iput(whiteout);
3702         }
3703         if (handle)
3704                 ext4_journal_stop(handle);
3705         return retval;
3706 }
3707 
3708 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3709                              struct inode *new_dir, struct dentry *new_dentry)
3710 {
3711         handle_t *handle = NULL;
3712         struct ext4_renament old = {
3713                 .dir = old_dir,
3714                 .dentry = old_dentry,
3715                 .inode = d_inode(old_dentry),
3716         };
3717         struct ext4_renament new = {
3718                 .dir = new_dir,
3719                 .dentry = new_dentry,
3720                 .inode = d_inode(new_dentry),
3721         };
3722         u8 new_file_type;
3723         int retval;
3724 
3725         if ((ext4_encrypted_inode(old_dir) ||
3726              ext4_encrypted_inode(new_dir)) &&
3727             (old_dir != new_dir) &&
3728             (!ext4_is_child_context_consistent_with_parent(new_dir,
3729                                                            old.inode) ||
3730              !ext4_is_child_context_consistent_with_parent(old_dir,
3731                                                            new.inode)))
3732                 return -EPERM;
3733 
3734         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
3735              !projid_eq(EXT4_I(new_dir)->i_projid,
3736                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
3737             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
3738              !projid_eq(EXT4_I(old_dir)->i_projid,
3739                         EXT4_I(new_dentry->d_inode)->i_projid)))
3740                 return -EXDEV;
3741 
3742         retval = dquot_initialize(old.dir);
3743         if (retval)
3744                 return retval;
3745         retval = dquot_initialize(new.dir);
3746         if (retval)
3747                 return retval;
3748 
3749         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3750                                  &old.de, &old.inlined);
3751         if (IS_ERR(old.bh))
3752                 return PTR_ERR(old.bh);
3753         /*
3754          *  Check for inode number is _not_ due to possible IO errors.
3755          *  We might rmdir the source, keep it as pwd of some process
3756          *  and merrily kill the link to whatever was created under the
3757          *  same name. Goodbye sticky bit ;-<
3758          */
3759         retval = -ENOENT;
3760         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3761                 goto end_rename;
3762 
3763         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3764                                  &new.de, &new.inlined);
3765         if (IS_ERR(new.bh)) {
3766                 retval = PTR_ERR(new.bh);
3767                 new.bh = NULL;
3768                 goto end_rename;
3769         }
3770 
3771         /* RENAME_EXCHANGE case: old *and* new must both exist */
3772         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3773                 goto end_rename;
3774 
3775         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3776                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3777                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3778         if (IS_ERR(handle)) {
3779                 retval = PTR_ERR(handle);
3780                 handle = NULL;
3781                 goto end_rename;
3782         }
3783 
3784         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3785                 ext4_handle_sync(handle);
3786 
3787         if (S_ISDIR(old.inode->i_mode)) {
3788                 old.is_dir = true;
3789                 retval = ext4_rename_dir_prepare(handle, &old);
3790                 if (retval)
3791                         goto end_rename;
3792         }
3793         if (S_ISDIR(new.inode->i_mode)) {
3794                 new.is_dir = true;
3795                 retval = ext4_rename_dir_prepare(handle, &new);
3796                 if (retval)
3797                         goto end_rename;
3798         }
3799 
3800         /*
3801          * Other than the special case of overwriting a directory, parents'
3802          * nlink only needs to be modified if this is a cross directory rename.
3803          */
3804         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3805                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3806                 new.dir_nlink_delta = -old.dir_nlink_delta;
3807                 retval = -EMLINK;
3808                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3809                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3810                         goto end_rename;
3811         }
3812 
3813         new_file_type = new.de->file_type;
3814         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3815         if (retval)
3816                 goto end_rename;
3817 
3818         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3819         if (retval)
3820                 goto end_rename;
3821 
3822         /*
3823          * Like most other Unix systems, set the ctime for inodes on a
3824          * rename.
3825          */
3826         old.inode->i_ctime = ext4_current_time(old.inode);
3827         new.inode->i_ctime = ext4_current_time(new.inode);
3828         ext4_mark_inode_dirty(handle, old.inode);
3829         ext4_mark_inode_dirty(handle, new.inode);
3830 
3831         if (old.dir_bh) {
3832                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3833                 if (retval)
3834                         goto end_rename;
3835         }
3836         if (new.dir_bh) {
3837                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3838                 if (retval)
3839                         goto end_rename;
3840         }
3841         ext4_update_dir_count(handle, &old);
3842         ext4_update_dir_count(handle, &new);
3843         retval = 0;
3844 
3845 end_rename:
3846         brelse(old.dir_bh);
3847         brelse(new.dir_bh);
3848         brelse(old.bh);
3849         brelse(new.bh);
3850         if (handle)
3851                 ext4_journal_stop(handle);
3852         return retval;
3853 }
3854 
3855 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3856                         struct inode *new_dir, struct dentry *new_dentry,
3857                         unsigned int flags)
3858 {
3859         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3860                 return -EINVAL;
3861 
3862         if (flags & RENAME_EXCHANGE) {
3863                 return ext4_cross_rename(old_dir, old_dentry,
3864                                          new_dir, new_dentry);
3865         }
3866 
3867         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3868 }
3869 
3870 /*
3871  * directories can handle most operations...
3872  */
3873 const struct inode_operations ext4_dir_inode_operations = {
3874         .create         = ext4_create,
3875         .lookup         = ext4_lookup,
3876         .link           = ext4_link,
3877         .unlink         = ext4_unlink,
3878         .symlink        = ext4_symlink,
3879         .mkdir          = ext4_mkdir,
3880         .rmdir          = ext4_rmdir,
3881         .mknod          = ext4_mknod,
3882         .tmpfile        = ext4_tmpfile,
3883         .rename2        = ext4_rename2,
3884         .setattr        = ext4_setattr,
3885         .setxattr       = generic_setxattr,
3886         .getxattr       = generic_getxattr,
3887         .listxattr      = ext4_listxattr,
3888         .removexattr    = generic_removexattr,
3889         .get_acl        = ext4_get_acl,
3890         .set_acl        = ext4_set_acl,
3891         .fiemap         = ext4_fiemap,
3892 };
3893 
3894 const struct inode_operations ext4_special_inode_operations = {
3895         .setattr        = ext4_setattr,
3896         .setxattr       = generic_setxattr,
3897         .getxattr       = generic_getxattr,
3898         .listxattr      = ext4_listxattr,
3899         .removexattr    = generic_removexattr,
3900         .get_acl        = ext4_get_acl,
3901         .set_acl        = ext4_set_acl,
3902 };
3903 

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