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Linux/fs/ext4/namei.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  linux/fs/ext4/namei.c
  4  *
  5  * Copyright (C) 1992, 1993, 1994, 1995
  6  * Remy Card (card@masi.ibp.fr)
  7  * Laboratoire MASI - Institut Blaise Pascal
  8  * Universite Pierre et Marie Curie (Paris VI)
  9  *
 10  *  from
 11  *
 12  *  linux/fs/minix/namei.c
 13  *
 14  *  Copyright (C) 1991, 1992  Linus Torvalds
 15  *
 16  *  Big-endian to little-endian byte-swapping/bitmaps by
 17  *        David S. Miller (davem@caip.rutgers.edu), 1995
 18  *  Directory entry file type support and forward compatibility hooks
 19  *      for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
 20  *  Hash Tree Directory indexing (c)
 21  *      Daniel Phillips, 2001
 22  *  Hash Tree Directory indexing porting
 23  *      Christopher Li, 2002
 24  *  Hash Tree Directory indexing cleanup
 25  *      Theodore Ts'o, 2002
 26  */
 27 
 28 #include <linux/fs.h>
 29 #include <linux/pagemap.h>
 30 #include <linux/time.h>
 31 #include <linux/fcntl.h>
 32 #include <linux/stat.h>
 33 #include <linux/string.h>
 34 #include <linux/quotaops.h>
 35 #include <linux/buffer_head.h>
 36 #include <linux/bio.h>
 37 #include "ext4.h"
 38 #include "ext4_jbd2.h"
 39 
 40 #include "xattr.h"
 41 #include "acl.h"
 42 
 43 #include <trace/events/ext4.h>
 44 /*
 45  * define how far ahead to read directories while searching them.
 46  */
 47 #define NAMEI_RA_CHUNKS  2
 48 #define NAMEI_RA_BLOCKS  4
 49 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
 50 
 51 static struct buffer_head *ext4_append(handle_t *handle,
 52                                         struct inode *inode,
 53                                         ext4_lblk_t *block)
 54 {
 55         struct buffer_head *bh;
 56         int err;
 57 
 58         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
 59                      ((inode->i_size >> 10) >=
 60                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
 61                 return ERR_PTR(-ENOSPC);
 62 
 63         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
 64 
 65         bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
 66         if (IS_ERR(bh))
 67                 return bh;
 68         inode->i_size += inode->i_sb->s_blocksize;
 69         EXT4_I(inode)->i_disksize = inode->i_size;
 70         BUFFER_TRACE(bh, "get_write_access");
 71         err = ext4_journal_get_write_access(handle, bh);
 72         if (err) {
 73                 brelse(bh);
 74                 ext4_std_error(inode->i_sb, err);
 75                 return ERR_PTR(err);
 76         }
 77         return bh;
 78 }
 79 
 80 static int ext4_dx_csum_verify(struct inode *inode,
 81                                struct ext4_dir_entry *dirent);
 82 
 83 typedef enum {
 84         EITHER, INDEX, DIRENT
 85 } dirblock_type_t;
 86 
 87 #define ext4_read_dirblock(inode, block, type) \
 88         __ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
 89 
 90 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
 91                                                 ext4_lblk_t block,
 92                                                 dirblock_type_t type,
 93                                                 const char *func,
 94                                                 unsigned int line)
 95 {
 96         struct buffer_head *bh;
 97         struct ext4_dir_entry *dirent;
 98         int is_dx_block = 0;
 99 
100         bh = ext4_bread(NULL, inode, block, 0);
101         if (IS_ERR(bh)) {
102                 __ext4_warning(inode->i_sb, func, line,
103                                "inode #%lu: lblock %lu: comm %s: "
104                                "error %ld reading directory block",
105                                inode->i_ino, (unsigned long)block,
106                                current->comm, PTR_ERR(bh));
107 
108                 return bh;
109         }
110         if (!bh) {
111                 ext4_error_inode(inode, func, line, block,
112                                  "Directory hole found");
113                 return ERR_PTR(-EFSCORRUPTED);
114         }
115         dirent = (struct ext4_dir_entry *) bh->b_data;
116         /* Determine whether or not we have an index block */
117         if (is_dx(inode)) {
118                 if (block == 0)
119                         is_dx_block = 1;
120                 else if (ext4_rec_len_from_disk(dirent->rec_len,
121                                                 inode->i_sb->s_blocksize) ==
122                          inode->i_sb->s_blocksize)
123                         is_dx_block = 1;
124         }
125         if (!is_dx_block && type == INDEX) {
126                 ext4_error_inode(inode, func, line, block,
127                        "directory leaf block found instead of index block");
128                 return ERR_PTR(-EFSCORRUPTED);
129         }
130         if (!ext4_has_metadata_csum(inode->i_sb) ||
131             buffer_verified(bh))
132                 return bh;
133 
134         /*
135          * An empty leaf block can get mistaken for a index block; for
136          * this reason, we can only check the index checksum when the
137          * caller is sure it should be an index block.
138          */
139         if (is_dx_block && type == INDEX) {
140                 if (ext4_dx_csum_verify(inode, dirent))
141                         set_buffer_verified(bh);
142                 else {
143                         ext4_error_inode(inode, func, line, block,
144                                          "Directory index failed checksum");
145                         brelse(bh);
146                         return ERR_PTR(-EFSBADCRC);
147                 }
148         }
149         if (!is_dx_block) {
150                 if (ext4_dirent_csum_verify(inode, dirent))
151                         set_buffer_verified(bh);
152                 else {
153                         ext4_error_inode(inode, func, line, block,
154                                          "Directory block failed checksum");
155                         brelse(bh);
156                         return ERR_PTR(-EFSBADCRC);
157                 }
158         }
159         return bh;
160 }
161 
162 #ifndef assert
163 #define assert(test) J_ASSERT(test)
164 #endif
165 
166 #ifdef DX_DEBUG
167 #define dxtrace(command) command
168 #else
169 #define dxtrace(command)
170 #endif
171 
172 struct fake_dirent
173 {
174         __le32 inode;
175         __le16 rec_len;
176         u8 name_len;
177         u8 file_type;
178 };
179 
180 struct dx_countlimit
181 {
182         __le16 limit;
183         __le16 count;
184 };
185 
186 struct dx_entry
187 {
188         __le32 hash;
189         __le32 block;
190 };
191 
192 /*
193  * dx_root_info is laid out so that if it should somehow get overlaid by a
194  * dirent the two low bits of the hash version will be zero.  Therefore, the
195  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
196  */
197 
198 struct dx_root
199 {
200         struct fake_dirent dot;
201         char dot_name[4];
202         struct fake_dirent dotdot;
203         char dotdot_name[4];
204         struct dx_root_info
205         {
206                 __le32 reserved_zero;
207                 u8 hash_version;
208                 u8 info_length; /* 8 */
209                 u8 indirect_levels;
210                 u8 unused_flags;
211         }
212         info;
213         struct dx_entry entries[0];
214 };
215 
216 struct dx_node
217 {
218         struct fake_dirent fake;
219         struct dx_entry entries[0];
220 };
221 
222 
223 struct dx_frame
224 {
225         struct buffer_head *bh;
226         struct dx_entry *entries;
227         struct dx_entry *at;
228 };
229 
230 struct dx_map_entry
231 {
232         u32 hash;
233         u16 offs;
234         u16 size;
235 };
236 
237 /*
238  * This goes at the end of each htree block.
239  */
240 struct dx_tail {
241         u32 dt_reserved;
242         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
243 };
244 
245 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
246 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
247 static inline unsigned dx_get_hash(struct dx_entry *entry);
248 static void dx_set_hash(struct dx_entry *entry, unsigned value);
249 static unsigned dx_get_count(struct dx_entry *entries);
250 static unsigned dx_get_limit(struct dx_entry *entries);
251 static void dx_set_count(struct dx_entry *entries, unsigned value);
252 static void dx_set_limit(struct dx_entry *entries, unsigned value);
253 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
254 static unsigned dx_node_limit(struct inode *dir);
255 static struct dx_frame *dx_probe(struct ext4_filename *fname,
256                                  struct inode *dir,
257                                  struct dx_hash_info *hinfo,
258                                  struct dx_frame *frame);
259 static void dx_release(struct dx_frame *frames);
260 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
261                        unsigned blocksize, struct dx_hash_info *hinfo,
262                        struct dx_map_entry map[]);
263 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
264 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
265                 struct dx_map_entry *offsets, int count, unsigned blocksize);
266 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
267 static void dx_insert_block(struct dx_frame *frame,
268                                         u32 hash, ext4_lblk_t block);
269 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
270                                  struct dx_frame *frame,
271                                  struct dx_frame *frames,
272                                  __u32 *start_hash);
273 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
274                 struct ext4_filename *fname,
275                 struct ext4_dir_entry_2 **res_dir);
276 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
277                              struct inode *dir, struct inode *inode);
278 
279 /* checksumming functions */
280 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
281                             unsigned int blocksize)
282 {
283         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
284         t->det_rec_len = ext4_rec_len_to_disk(
285                         sizeof(struct ext4_dir_entry_tail), blocksize);
286         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
287 }
288 
289 /* Walk through a dirent block to find a checksum "dirent" at the tail */
290 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
291                                                    struct ext4_dir_entry *de)
292 {
293         struct ext4_dir_entry_tail *t;
294 
295 #ifdef PARANOID
296         struct ext4_dir_entry *d, *top;
297 
298         d = de;
299         top = (struct ext4_dir_entry *)(((void *)de) +
300                 (EXT4_BLOCK_SIZE(inode->i_sb) -
301                 sizeof(struct ext4_dir_entry_tail)));
302         while (d < top && d->rec_len)
303                 d = (struct ext4_dir_entry *)(((void *)d) +
304                     le16_to_cpu(d->rec_len));
305 
306         if (d != top)
307                 return NULL;
308 
309         t = (struct ext4_dir_entry_tail *)d;
310 #else
311         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
312 #endif
313 
314         if (t->det_reserved_zero1 ||
315             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
316             t->det_reserved_zero2 ||
317             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
318                 return NULL;
319 
320         return t;
321 }
322 
323 static __le32 ext4_dirent_csum(struct inode *inode,
324                                struct ext4_dir_entry *dirent, int size)
325 {
326         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
327         struct ext4_inode_info *ei = EXT4_I(inode);
328         __u32 csum;
329 
330         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
331         return cpu_to_le32(csum);
332 }
333 
334 #define warn_no_space_for_csum(inode)                                   \
335         __warn_no_space_for_csum((inode), __func__, __LINE__)
336 
337 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
338                                      unsigned int line)
339 {
340         __ext4_warning_inode(inode, func, line,
341                 "No space for directory leaf checksum. Please run e2fsck -D.");
342 }
343 
344 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
345 {
346         struct ext4_dir_entry_tail *t;
347 
348         if (!ext4_has_metadata_csum(inode->i_sb))
349                 return 1;
350 
351         t = get_dirent_tail(inode, dirent);
352         if (!t) {
353                 warn_no_space_for_csum(inode);
354                 return 0;
355         }
356 
357         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
358                                                 (void *)t - (void *)dirent))
359                 return 0;
360 
361         return 1;
362 }
363 
364 static void ext4_dirent_csum_set(struct inode *inode,
365                                  struct ext4_dir_entry *dirent)
366 {
367         struct ext4_dir_entry_tail *t;
368 
369         if (!ext4_has_metadata_csum(inode->i_sb))
370                 return;
371 
372         t = get_dirent_tail(inode, dirent);
373         if (!t) {
374                 warn_no_space_for_csum(inode);
375                 return;
376         }
377 
378         t->det_checksum = ext4_dirent_csum(inode, dirent,
379                                            (void *)t - (void *)dirent);
380 }
381 
382 int ext4_handle_dirty_dirent_node(handle_t *handle,
383                                   struct inode *inode,
384                                   struct buffer_head *bh)
385 {
386         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
387         return ext4_handle_dirty_metadata(handle, inode, bh);
388 }
389 
390 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
391                                                struct ext4_dir_entry *dirent,
392                                                int *offset)
393 {
394         struct ext4_dir_entry *dp;
395         struct dx_root_info *root;
396         int count_offset;
397 
398         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
399                 count_offset = 8;
400         else if (le16_to_cpu(dirent->rec_len) == 12) {
401                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
402                 if (le16_to_cpu(dp->rec_len) !=
403                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
404                         return NULL;
405                 root = (struct dx_root_info *)(((void *)dp + 12));
406                 if (root->reserved_zero ||
407                     root->info_length != sizeof(struct dx_root_info))
408                         return NULL;
409                 count_offset = 32;
410         } else
411                 return NULL;
412 
413         if (offset)
414                 *offset = count_offset;
415         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
416 }
417 
418 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
419                            int count_offset, int count, struct dx_tail *t)
420 {
421         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
422         struct ext4_inode_info *ei = EXT4_I(inode);
423         __u32 csum;
424         int size;
425         __u32 dummy_csum = 0;
426         int offset = offsetof(struct dx_tail, dt_checksum);
427 
428         size = count_offset + (count * sizeof(struct dx_entry));
429         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
430         csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
431         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_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 0;
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 0;
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) & 0x0fffffff;
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(KERN_CONT " %x->%lu",
584                        i ? dx_get_hash(entries + i) : 0,
585                        (unsigned long)dx_get_block(entries + i));
586         }
587         printk(KERN_CONT "\n");
588 }
589 
590 struct stats
591 {
592         unsigned names;
593         unsigned space;
594         unsigned bcount;
595 };
596 
597 static struct stats dx_show_leaf(struct inode *dir,
598                                 struct dx_hash_info *hinfo,
599                                 struct ext4_dir_entry_2 *de,
600                                 int size, int show_names)
601 {
602         unsigned names = 0, space = 0;
603         char *base = (char *) de;
604         struct dx_hash_info h = *hinfo;
605 
606         printk("names: ");
607         while ((char *) de < base + size)
608         {
609                 if (de->inode)
610                 {
611                         if (show_names)
612                         {
613 #ifdef CONFIG_EXT4_FS_ENCRYPTION
614                                 int len;
615                                 char *name;
616                                 struct fscrypt_str fname_crypto_str =
617                                         FSTR_INIT(NULL, 0);
618                                 int res = 0;
619 
620                                 name  = de->name;
621                                 len = de->name_len;
622                                 if (ext4_encrypted_inode(dir))
623                                         res = fscrypt_get_encryption_info(dir);
624                                 if (res) {
625                                         printk(KERN_WARNING "Error setting up"
626                                                " fname crypto: %d\n", res);
627                                 }
628                                 if (!fscrypt_has_encryption_key(dir)) {
629                                         /* Directory is not encrypted */
630                                         ext4fs_dirhash(de->name,
631                                                 de->name_len, &h);
632                                         printk("%*.s:(U)%x.%u ", len,
633                                                name, h.hash,
634                                                (unsigned) ((char *) de
635                                                            - base));
636                                 } else {
637                                         struct fscrypt_str de_name =
638                                                 FSTR_INIT(name, len);
639 
640                                         /* Directory is encrypted */
641                                         res = fscrypt_fname_alloc_buffer(
642                                                 dir, len,
643                                                 &fname_crypto_str);
644                                         if (res)
645                                                 printk(KERN_WARNING "Error "
646                                                         "allocating crypto "
647                                                         "buffer--skipping "
648                                                         "crypto\n");
649                                         res = fscrypt_fname_disk_to_usr(dir,
650                                                 0, 0, &de_name,
651                                                 &fname_crypto_str);
652                                         if (res) {
653                                                 printk(KERN_WARNING "Error "
654                                                         "converting filename "
655                                                         "from disk to usr"
656                                                         "\n");
657                                                 name = "??";
658                                                 len = 2;
659                                         } else {
660                                                 name = fname_crypto_str.name;
661                                                 len = fname_crypto_str.len;
662                                         }
663                                         ext4fs_dirhash(de->name, de->name_len,
664                                                        &h);
665                                         printk("%*.s:(E)%x.%u ", len, name,
666                                                h.hash, (unsigned) ((char *) de
667                                                                    - base));
668                                         fscrypt_fname_free_buffer(
669                                                         &fname_crypto_str);
670                                 }
671 #else
672                                 int len = de->name_len;
673                                 char *name = de->name;
674                                 ext4fs_dirhash(de->name, de->name_len, &h);
675                                 printk("%*.s:%x.%u ", len, name, h.hash,
676                                        (unsigned) ((char *) de - base));
677 #endif
678                         }
679                         space += EXT4_DIR_REC_LEN(de->name_len);
680                         names++;
681                 }
682                 de = ext4_next_entry(de, size);
683         }
684         printk(KERN_CONT "(%i)\n", names);
685         return (struct stats) { names, space, 1 };
686 }
687 
688 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
689                              struct dx_entry *entries, int levels)
690 {
691         unsigned blocksize = dir->i_sb->s_blocksize;
692         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
693         unsigned bcount = 0;
694         struct buffer_head *bh;
695         printk("%i indexed blocks...\n", count);
696         for (i = 0; i < count; i++, entries++)
697         {
698                 ext4_lblk_t block = dx_get_block(entries);
699                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
700                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
701                 struct stats stats;
702                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
703                 bh = ext4_bread(NULL,dir, block, 0);
704                 if (!bh || IS_ERR(bh))
705                         continue;
706                 stats = levels?
707                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
708                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
709                         bh->b_data, blocksize, 0);
710                 names += stats.names;
711                 space += stats.space;
712                 bcount += stats.bcount;
713                 brelse(bh);
714         }
715         if (bcount)
716                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
717                        levels ? "" : "   ", names, space/bcount,
718                        (space/bcount)*100/blocksize);
719         return (struct stats) { names, space, bcount};
720 }
721 #endif /* DX_DEBUG */
722 
723 /*
724  * Probe for a directory leaf block to search.
725  *
726  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
727  * error in the directory index, and the caller should fall back to
728  * searching the directory normally.  The callers of dx_probe **MUST**
729  * check for this error code, and make sure it never gets reflected
730  * back to userspace.
731  */
732 static struct dx_frame *
733 dx_probe(struct ext4_filename *fname, struct inode *dir,
734          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
735 {
736         unsigned count, indirect;
737         struct dx_entry *at, *entries, *p, *q, *m;
738         struct dx_root *root;
739         struct dx_frame *frame = frame_in;
740         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
741         u32 hash;
742 
743         memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
744         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
745         if (IS_ERR(frame->bh))
746                 return (struct dx_frame *) frame->bh;
747 
748         root = (struct dx_root *) frame->bh->b_data;
749         if (root->info.hash_version != DX_HASH_TEA &&
750             root->info.hash_version != DX_HASH_HALF_MD4 &&
751             root->info.hash_version != DX_HASH_LEGACY) {
752                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
753                                    root->info.hash_version);
754                 goto fail;
755         }
756         if (fname)
757                 hinfo = &fname->hinfo;
758         hinfo->hash_version = root->info.hash_version;
759         if (hinfo->hash_version <= DX_HASH_TEA)
760                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
761         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
762         if (fname && fname_name(fname))
763                 ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
764         hash = hinfo->hash;
765 
766         if (root->info.unused_flags & 1) {
767                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
768                                    root->info.unused_flags);
769                 goto fail;
770         }
771 
772         indirect = root->info.indirect_levels;
773         if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
774                 ext4_warning(dir->i_sb,
775                              "Directory (ino: %lu) htree depth %#06x exceed"
776                              "supported value", dir->i_ino,
777                              ext4_dir_htree_level(dir->i_sb));
778                 if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
779                         ext4_warning(dir->i_sb, "Enable large directory "
780                                                 "feature to access it");
781                 }
782                 goto fail;
783         }
784 
785         entries = (struct dx_entry *)(((char *)&root->info) +
786                                       root->info.info_length);
787 
788         if (dx_get_limit(entries) != dx_root_limit(dir,
789                                                    root->info.info_length)) {
790                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
791                                    dx_get_limit(entries),
792                                    dx_root_limit(dir, root->info.info_length));
793                 goto fail;
794         }
795 
796         dxtrace(printk("Look up %x", hash));
797         while (1) {
798                 count = dx_get_count(entries);
799                 if (!count || count > dx_get_limit(entries)) {
800                         ext4_warning_inode(dir,
801                                            "dx entry: count %u beyond limit %u",
802                                            count, dx_get_limit(entries));
803                         goto fail;
804                 }
805 
806                 p = entries + 1;
807                 q = entries + count - 1;
808                 while (p <= q) {
809                         m = p + (q - p) / 2;
810                         dxtrace(printk(KERN_CONT "."));
811                         if (dx_get_hash(m) > hash)
812                                 q = m - 1;
813                         else
814                                 p = m + 1;
815                 }
816 
817                 if (0) { // linear search cross check
818                         unsigned n = count - 1;
819                         at = entries;
820                         while (n--)
821                         {
822                                 dxtrace(printk(KERN_CONT ","));
823                                 if (dx_get_hash(++at) > hash)
824                                 {
825                                         at--;
826                                         break;
827                                 }
828                         }
829                         assert (at == p - 1);
830                 }
831 
832                 at = p - 1;
833                 dxtrace(printk(KERN_CONT " %x->%u\n",
834                                at == entries ? 0 : dx_get_hash(at),
835                                dx_get_block(at)));
836                 frame->entries = entries;
837                 frame->at = at;
838                 if (!indirect--)
839                         return frame;
840                 frame++;
841                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
842                 if (IS_ERR(frame->bh)) {
843                         ret_err = (struct dx_frame *) frame->bh;
844                         frame->bh = NULL;
845                         goto fail;
846                 }
847                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
848 
849                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
850                         ext4_warning_inode(dir,
851                                 "dx entry: limit %u != node limit %u",
852                                 dx_get_limit(entries), dx_node_limit(dir));
853                         goto fail;
854                 }
855         }
856 fail:
857         while (frame >= frame_in) {
858                 brelse(frame->bh);
859                 frame--;
860         }
861 
862         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
863                 ext4_warning_inode(dir,
864                         "Corrupt directory, running e2fsck is recommended");
865         return ret_err;
866 }
867 
868 static void dx_release(struct dx_frame *frames)
869 {
870         struct dx_root_info *info;
871         int i;
872 
873         if (frames[0].bh == NULL)
874                 return;
875 
876         info = &((struct dx_root *)frames[0].bh->b_data)->info;
877         for (i = 0; i <= info->indirect_levels; i++) {
878                 if (frames[i].bh == NULL)
879                         break;
880                 brelse(frames[i].bh);
881                 frames[i].bh = NULL;
882         }
883 }
884 
885 /*
886  * This function increments the frame pointer to search the next leaf
887  * block, and reads in the necessary intervening nodes if the search
888  * should be necessary.  Whether or not the search is necessary is
889  * controlled by the hash parameter.  If the hash value is even, then
890  * the search is only continued if the next block starts with that
891  * hash value.  This is used if we are searching for a specific file.
892  *
893  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
894  *
895  * This function returns 1 if the caller should continue to search,
896  * or 0 if it should not.  If there is an error reading one of the
897  * index blocks, it will a negative error code.
898  *
899  * If start_hash is non-null, it will be filled in with the starting
900  * hash of the next page.
901  */
902 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
903                                  struct dx_frame *frame,
904                                  struct dx_frame *frames,
905                                  __u32 *start_hash)
906 {
907         struct dx_frame *p;
908         struct buffer_head *bh;
909         int num_frames = 0;
910         __u32 bhash;
911 
912         p = frame;
913         /*
914          * Find the next leaf page by incrementing the frame pointer.
915          * If we run out of entries in the interior node, loop around and
916          * increment pointer in the parent node.  When we break out of
917          * this loop, num_frames indicates the number of interior
918          * nodes need to be read.
919          */
920         while (1) {
921                 if (++(p->at) < p->entries + dx_get_count(p->entries))
922                         break;
923                 if (p == frames)
924                         return 0;
925                 num_frames++;
926                 p--;
927         }
928 
929         /*
930          * If the hash is 1, then continue only if the next page has a
931          * continuation hash of any value.  This is used for readdir
932          * handling.  Otherwise, check to see if the hash matches the
933          * desired contiuation hash.  If it doesn't, return since
934          * there's no point to read in the successive index pages.
935          */
936         bhash = dx_get_hash(p->at);
937         if (start_hash)
938                 *start_hash = bhash;
939         if ((hash & 1) == 0) {
940                 if ((bhash & ~1) != hash)
941                         return 0;
942         }
943         /*
944          * If the hash is HASH_NB_ALWAYS, we always go to the next
945          * block so no check is necessary
946          */
947         while (num_frames--) {
948                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
949                 if (IS_ERR(bh))
950                         return PTR_ERR(bh);
951                 p++;
952                 brelse(p->bh);
953                 p->bh = bh;
954                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
955         }
956         return 1;
957 }
958 
959 
960 /*
961  * This function fills a red-black tree with information from a
962  * directory block.  It returns the number directory entries loaded
963  * into the tree.  If there is an error it is returned in err.
964  */
965 static int htree_dirblock_to_tree(struct file *dir_file,
966                                   struct inode *dir, ext4_lblk_t block,
967                                   struct dx_hash_info *hinfo,
968                                   __u32 start_hash, __u32 start_minor_hash)
969 {
970         struct buffer_head *bh;
971         struct ext4_dir_entry_2 *de, *top;
972         int err = 0, count = 0;
973         struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
974 
975         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
976                                                         (unsigned long)block));
977         bh = ext4_read_dirblock(dir, block, DIRENT);
978         if (IS_ERR(bh))
979                 return PTR_ERR(bh);
980 
981         de = (struct ext4_dir_entry_2 *) bh->b_data;
982         top = (struct ext4_dir_entry_2 *) ((char *) de +
983                                            dir->i_sb->s_blocksize -
984                                            EXT4_DIR_REC_LEN(0));
985 #ifdef CONFIG_EXT4_FS_ENCRYPTION
986         /* Check if the directory is encrypted */
987         if (ext4_encrypted_inode(dir)) {
988                 err = fscrypt_get_encryption_info(dir);
989                 if (err < 0) {
990                         brelse(bh);
991                         return err;
992                 }
993                 err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
994                                                      &fname_crypto_str);
995                 if (err < 0) {
996                         brelse(bh);
997                         return err;
998                 }
999         }
1000 #endif
1001         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
1002                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1003                                 bh->b_data, bh->b_size,
1004                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
1005                                          + ((char *)de - bh->b_data))) {
1006                         /* silently ignore the rest of the block */
1007                         break;
1008                 }
1009                 ext4fs_dirhash(de->name, de->name_len, hinfo);
1010                 if ((hinfo->hash < start_hash) ||
1011                     ((hinfo->hash == start_hash) &&
1012                      (hinfo->minor_hash < start_minor_hash)))
1013                         continue;
1014                 if (de->inode == 0)
1015                         continue;
1016                 if (!ext4_encrypted_inode(dir)) {
1017                         tmp_str.name = de->name;
1018                         tmp_str.len = de->name_len;
1019                         err = ext4_htree_store_dirent(dir_file,
1020                                    hinfo->hash, hinfo->minor_hash, de,
1021                                    &tmp_str);
1022                 } else {
1023                         int save_len = fname_crypto_str.len;
1024                         struct fscrypt_str de_name = FSTR_INIT(de->name,
1025                                                                 de->name_len);
1026 
1027                         /* Directory is encrypted */
1028                         err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1029                                         hinfo->minor_hash, &de_name,
1030                                         &fname_crypto_str);
1031                         if (err) {
1032                                 count = err;
1033                                 goto errout;
1034                         }
1035                         err = ext4_htree_store_dirent(dir_file,
1036                                    hinfo->hash, hinfo->minor_hash, de,
1037                                         &fname_crypto_str);
1038                         fname_crypto_str.len = save_len;
1039                 }
1040                 if (err != 0) {
1041                         count = err;
1042                         goto errout;
1043                 }
1044                 count++;
1045         }
1046 errout:
1047         brelse(bh);
1048 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1049         fscrypt_fname_free_buffer(&fname_crypto_str);
1050 #endif
1051         return count;
1052 }
1053 
1054 
1055 /*
1056  * This function fills a red-black tree with information from a
1057  * directory.  We start scanning the directory in hash order, starting
1058  * at start_hash and start_minor_hash.
1059  *
1060  * This function returns the number of entries inserted into the tree,
1061  * or a negative error code.
1062  */
1063 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1064                          __u32 start_minor_hash, __u32 *next_hash)
1065 {
1066         struct dx_hash_info hinfo;
1067         struct ext4_dir_entry_2 *de;
1068         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1069         struct inode *dir;
1070         ext4_lblk_t block;
1071         int count = 0;
1072         int ret, err;
1073         __u32 hashval;
1074         struct fscrypt_str tmp_str;
1075 
1076         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1077                        start_hash, start_minor_hash));
1078         dir = file_inode(dir_file);
1079         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1080                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1081                 if (hinfo.hash_version <= DX_HASH_TEA)
1082                         hinfo.hash_version +=
1083                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1084                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1085                 if (ext4_has_inline_data(dir)) {
1086                         int has_inline_data = 1;
1087                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
1088                                                         &hinfo, start_hash,
1089                                                         start_minor_hash,
1090                                                         &has_inline_data);
1091                         if (has_inline_data) {
1092                                 *next_hash = ~0;
1093                                 return count;
1094                         }
1095                 }
1096                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1097                                                start_hash, start_minor_hash);
1098                 *next_hash = ~0;
1099                 return count;
1100         }
1101         hinfo.hash = start_hash;
1102         hinfo.minor_hash = 0;
1103         frame = dx_probe(NULL, dir, &hinfo, frames);
1104         if (IS_ERR(frame))
1105                 return PTR_ERR(frame);
1106 
1107         /* Add '.' and '..' from the htree header */
1108         if (!start_hash && !start_minor_hash) {
1109                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1110                 tmp_str.name = de->name;
1111                 tmp_str.len = de->name_len;
1112                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1113                                               de, &tmp_str);
1114                 if (err != 0)
1115                         goto errout;
1116                 count++;
1117         }
1118         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1119                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1120                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1121                 tmp_str.name = de->name;
1122                 tmp_str.len = de->name_len;
1123                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1124                                               de, &tmp_str);
1125                 if (err != 0)
1126                         goto errout;
1127                 count++;
1128         }
1129 
1130         while (1) {
1131                 if (fatal_signal_pending(current)) {
1132                         err = -ERESTARTSYS;
1133                         goto errout;
1134                 }
1135                 cond_resched();
1136                 block = dx_get_block(frame->at);
1137                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1138                                              start_hash, start_minor_hash);
1139                 if (ret < 0) {
1140                         err = ret;
1141                         goto errout;
1142                 }
1143                 count += ret;
1144                 hashval = ~0;
1145                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1146                                             frame, frames, &hashval);
1147                 *next_hash = hashval;
1148                 if (ret < 0) {
1149                         err = ret;
1150                         goto errout;
1151                 }
1152                 /*
1153                  * Stop if:  (a) there are no more entries, or
1154                  * (b) we have inserted at least one entry and the
1155                  * next hash value is not a continuation
1156                  */
1157                 if ((ret == 0) ||
1158                     (count && ((hashval & 1) == 0)))
1159                         break;
1160         }
1161         dx_release(frames);
1162         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1163                        "next hash: %x\n", count, *next_hash));
1164         return count;
1165 errout:
1166         dx_release(frames);
1167         return (err);
1168 }
1169 
1170 static inline int search_dirblock(struct buffer_head *bh,
1171                                   struct inode *dir,
1172                                   struct ext4_filename *fname,
1173                                   unsigned int offset,
1174                                   struct ext4_dir_entry_2 **res_dir)
1175 {
1176         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1177                                fname, offset, res_dir);
1178 }
1179 
1180 /*
1181  * Directory block splitting, compacting
1182  */
1183 
1184 /*
1185  * Create map of hash values, offsets, and sizes, stored at end of block.
1186  * Returns number of entries mapped.
1187  */
1188 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
1189                        unsigned blocksize, struct dx_hash_info *hinfo,
1190                        struct dx_map_entry *map_tail)
1191 {
1192         int count = 0;
1193         char *base = (char *) de;
1194         struct dx_hash_info h = *hinfo;
1195 
1196         while ((char *) de < base + blocksize) {
1197                 if (de->name_len && de->inode) {
1198                         ext4fs_dirhash(de->name, de->name_len, &h);
1199                         map_tail--;
1200                         map_tail->hash = h.hash;
1201                         map_tail->offs = ((char *) de - base)>>2;
1202                         map_tail->size = le16_to_cpu(de->rec_len);
1203                         count++;
1204                         cond_resched();
1205                 }
1206                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1207                 de = ext4_next_entry(de, blocksize);
1208         }
1209         return count;
1210 }
1211 
1212 /* Sort map by hash value */
1213 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1214 {
1215         struct dx_map_entry *p, *q, *top = map + count - 1;
1216         int more;
1217         /* Combsort until bubble sort doesn't suck */
1218         while (count > 2) {
1219                 count = count*10/13;
1220                 if (count - 9 < 2) /* 9, 10 -> 11 */
1221                         count = 11;
1222                 for (p = top, q = p - count; q >= map; p--, q--)
1223                         if (p->hash < q->hash)
1224                                 swap(*p, *q);
1225         }
1226         /* Garden variety bubble sort */
1227         do {
1228                 more = 0;
1229                 q = top;
1230                 while (q-- > map) {
1231                         if (q[1].hash >= q[0].hash)
1232                                 continue;
1233                         swap(*(q+1), *q);
1234                         more = 1;
1235                 }
1236         } while(more);
1237 }
1238 
1239 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1240 {
1241         struct dx_entry *entries = frame->entries;
1242         struct dx_entry *old = frame->at, *new = old + 1;
1243         int count = dx_get_count(entries);
1244 
1245         assert(count < dx_get_limit(entries));
1246         assert(old < entries + count);
1247         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1248         dx_set_hash(new, hash);
1249         dx_set_block(new, block);
1250         dx_set_count(entries, count + 1);
1251 }
1252 
1253 /*
1254  * Test whether a directory entry matches the filename being searched for.
1255  *
1256  * Return: %true if the directory entry matches, otherwise %false.
1257  */
1258 static inline bool ext4_match(const struct ext4_filename *fname,
1259                               const struct ext4_dir_entry_2 *de)
1260 {
1261         struct fscrypt_name f;
1262 
1263         if (!de->inode)
1264                 return false;
1265 
1266         f.usr_fname = fname->usr_fname;
1267         f.disk_name = fname->disk_name;
1268 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1269         f.crypto_buf = fname->crypto_buf;
1270 #endif
1271         return fscrypt_match_name(&f, de->name, de->name_len);
1272 }
1273 
1274 /*
1275  * Returns 0 if not found, -1 on failure, and 1 on success
1276  */
1277 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1278                     struct inode *dir, struct ext4_filename *fname,
1279                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1280 {
1281         struct ext4_dir_entry_2 * de;
1282         char * dlimit;
1283         int de_len;
1284 
1285         de = (struct ext4_dir_entry_2 *)search_buf;
1286         dlimit = search_buf + buf_size;
1287         while ((char *) de < dlimit) {
1288                 /* this code is executed quadratically often */
1289                 /* do minimal checking `by hand' */
1290                 if ((char *) de + de->name_len <= dlimit &&
1291                     ext4_match(fname, de)) {
1292                         /* found a match - just to be sure, do
1293                          * a full check */
1294                         if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
1295                                                  bh->b_size, offset))
1296                                 return -1;
1297                         *res_dir = de;
1298                         return 1;
1299                 }
1300                 /* prevent looping on a bad block */
1301                 de_len = ext4_rec_len_from_disk(de->rec_len,
1302                                                 dir->i_sb->s_blocksize);
1303                 if (de_len <= 0)
1304                         return -1;
1305                 offset += de_len;
1306                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1307         }
1308         return 0;
1309 }
1310 
1311 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1312                                struct ext4_dir_entry *de)
1313 {
1314         struct super_block *sb = dir->i_sb;
1315 
1316         if (!is_dx(dir))
1317                 return 0;
1318         if (block == 0)
1319                 return 1;
1320         if (de->inode == 0 &&
1321             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1322                         sb->s_blocksize)
1323                 return 1;
1324         return 0;
1325 }
1326 
1327 /*
1328  *      ext4_find_entry()
1329  *
1330  * finds an entry in the specified directory with the wanted name. It
1331  * returns the cache buffer in which the entry was found, and the entry
1332  * itself (as a parameter - res_dir). It does NOT read the inode of the
1333  * entry - you'll have to do that yourself if you want to.
1334  *
1335  * The returned buffer_head has ->b_count elevated.  The caller is expected
1336  * to brelse() it when appropriate.
1337  */
1338 static struct buffer_head * ext4_find_entry (struct inode *dir,
1339                                         const struct qstr *d_name,
1340                                         struct ext4_dir_entry_2 **res_dir,
1341                                         int *inlined)
1342 {
1343         struct super_block *sb;
1344         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1345         struct buffer_head *bh, *ret = NULL;
1346         ext4_lblk_t start, block;
1347         const u8 *name = d_name->name;
1348         size_t ra_max = 0;      /* Number of bh's in the readahead
1349                                    buffer, bh_use[] */
1350         size_t ra_ptr = 0;      /* Current index into readahead
1351                                    buffer */
1352         ext4_lblk_t  nblocks;
1353         int i, namelen, retval;
1354         struct ext4_filename fname;
1355 
1356         *res_dir = NULL;
1357         sb = dir->i_sb;
1358         namelen = d_name->len;
1359         if (namelen > EXT4_NAME_LEN)
1360                 return NULL;
1361 
1362         retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1363         if (retval == -ENOENT)
1364                 return NULL;
1365         if (retval)
1366                 return ERR_PTR(retval);
1367 
1368         if (ext4_has_inline_data(dir)) {
1369                 int has_inline_data = 1;
1370                 ret = ext4_find_inline_entry(dir, &fname, res_dir,
1371                                              &has_inline_data);
1372                 if (has_inline_data) {
1373                         if (inlined)
1374                                 *inlined = 1;
1375                         goto cleanup_and_exit;
1376                 }
1377         }
1378 
1379         if ((namelen <= 2) && (name[0] == '.') &&
1380             (name[1] == '.' || name[1] == '\0')) {
1381                 /*
1382                  * "." or ".." will only be in the first block
1383                  * NFS may look up ".."; "." should be handled by the VFS
1384                  */
1385                 block = start = 0;
1386                 nblocks = 1;
1387                 goto restart;
1388         }
1389         if (is_dx(dir)) {
1390                 ret = ext4_dx_find_entry(dir, &fname, res_dir);
1391                 /*
1392                  * On success, or if the error was file not found,
1393                  * return.  Otherwise, fall back to doing a search the
1394                  * old fashioned way.
1395                  */
1396                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1397                         goto cleanup_and_exit;
1398                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1399                                "falling back\n"));
1400         }
1401         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1402         start = EXT4_I(dir)->i_dir_start_lookup;
1403         if (start >= nblocks)
1404                 start = 0;
1405         block = start;
1406 restart:
1407         do {
1408                 /*
1409                  * We deal with the read-ahead logic here.
1410                  */
1411                 if (ra_ptr >= ra_max) {
1412                         /* Refill the readahead buffer */
1413                         ra_ptr = 0;
1414                         if (block < start)
1415                                 ra_max = start - block;
1416                         else
1417                                 ra_max = nblocks - block;
1418                         ra_max = min(ra_max, ARRAY_SIZE(bh_use));
1419                         retval = ext4_bread_batch(dir, block, ra_max,
1420                                                   false /* wait */, bh_use);
1421                         if (retval) {
1422                                 ret = ERR_PTR(retval);
1423                                 ra_max = 0;
1424                                 goto cleanup_and_exit;
1425                         }
1426                 }
1427                 if ((bh = bh_use[ra_ptr++]) == NULL)
1428                         goto next;
1429                 wait_on_buffer(bh);
1430                 if (!buffer_uptodate(bh)) {
1431                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1432                                          (unsigned long) block);
1433                         brelse(bh);
1434                         ret = ERR_PTR(-EIO);
1435                         goto cleanup_and_exit;
1436                 }
1437                 if (!buffer_verified(bh) &&
1438                     !is_dx_internal_node(dir, block,
1439                                          (struct ext4_dir_entry *)bh->b_data) &&
1440                     !ext4_dirent_csum_verify(dir,
1441                                 (struct ext4_dir_entry *)bh->b_data)) {
1442                         EXT4_ERROR_INODE(dir, "checksumming directory "
1443                                          "block %lu", (unsigned long)block);
1444                         brelse(bh);
1445                         ret = ERR_PTR(-EFSBADCRC);
1446                         goto cleanup_and_exit;
1447                 }
1448                 set_buffer_verified(bh);
1449                 i = search_dirblock(bh, dir, &fname,
1450                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1451                 if (i == 1) {
1452                         EXT4_I(dir)->i_dir_start_lookup = block;
1453                         ret = bh;
1454                         goto cleanup_and_exit;
1455                 } else {
1456                         brelse(bh);
1457                         if (i < 0)
1458                                 goto cleanup_and_exit;
1459                 }
1460         next:
1461                 if (++block >= nblocks)
1462                         block = 0;
1463         } while (block != start);
1464 
1465         /*
1466          * If the directory has grown while we were searching, then
1467          * search the last part of the directory before giving up.
1468          */
1469         block = nblocks;
1470         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1471         if (block < nblocks) {
1472                 start = 0;
1473                 goto restart;
1474         }
1475 
1476 cleanup_and_exit:
1477         /* Clean up the read-ahead blocks */
1478         for (; ra_ptr < ra_max; ra_ptr++)
1479                 brelse(bh_use[ra_ptr]);
1480         ext4_fname_free_filename(&fname);
1481         return ret;
1482 }
1483 
1484 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1485                         struct ext4_filename *fname,
1486                         struct ext4_dir_entry_2 **res_dir)
1487 {
1488         struct super_block * sb = dir->i_sb;
1489         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1490         struct buffer_head *bh;
1491         ext4_lblk_t block;
1492         int retval;
1493 
1494 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1495         *res_dir = NULL;
1496 #endif
1497         frame = dx_probe(fname, dir, NULL, frames);
1498         if (IS_ERR(frame))
1499                 return (struct buffer_head *) frame;
1500         do {
1501                 block = dx_get_block(frame->at);
1502                 bh = ext4_read_dirblock(dir, block, DIRENT);
1503                 if (IS_ERR(bh))
1504                         goto errout;
1505 
1506                 retval = search_dirblock(bh, dir, fname,
1507                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1508                                          res_dir);
1509                 if (retval == 1)
1510                         goto success;
1511                 brelse(bh);
1512                 if (retval == -1) {
1513                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1514                         goto errout;
1515                 }
1516 
1517                 /* Check to see if we should continue to search */
1518                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1519                                                frames, NULL);
1520                 if (retval < 0) {
1521                         ext4_warning_inode(dir,
1522                                 "error %d reading directory index block",
1523                                 retval);
1524                         bh = ERR_PTR(retval);
1525                         goto errout;
1526                 }
1527         } while (retval == 1);
1528 
1529         bh = NULL;
1530 errout:
1531         dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1532 success:
1533         dx_release(frames);
1534         return bh;
1535 }
1536 
1537 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1538 {
1539         struct inode *inode;
1540         struct ext4_dir_entry_2 *de;
1541         struct buffer_head *bh;
1542         int err;
1543 
1544         err = fscrypt_prepare_lookup(dir, dentry, flags);
1545         if (err)
1546                 return ERR_PTR(err);
1547 
1548         if (dentry->d_name.len > EXT4_NAME_LEN)
1549                 return ERR_PTR(-ENAMETOOLONG);
1550 
1551         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1552         if (IS_ERR(bh))
1553                 return (struct dentry *) bh;
1554         inode = NULL;
1555         if (bh) {
1556                 __u32 ino = le32_to_cpu(de->inode);
1557                 brelse(bh);
1558                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1559                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1560                         return ERR_PTR(-EFSCORRUPTED);
1561                 }
1562                 if (unlikely(ino == dir->i_ino)) {
1563                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1564                                          dentry);
1565                         return ERR_PTR(-EFSCORRUPTED);
1566                 }
1567                 inode = ext4_iget_normal(dir->i_sb, ino);
1568                 if (inode == ERR_PTR(-ESTALE)) {
1569                         EXT4_ERROR_INODE(dir,
1570                                          "deleted inode referenced: %u",
1571                                          ino);
1572                         return ERR_PTR(-EFSCORRUPTED);
1573                 }
1574                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1575                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1576                     !fscrypt_has_permitted_context(dir, inode)) {
1577                         ext4_warning(inode->i_sb,
1578                                      "Inconsistent encryption contexts: %lu/%lu",
1579                                      dir->i_ino, inode->i_ino);
1580                         iput(inode);
1581                         return ERR_PTR(-EPERM);
1582                 }
1583         }
1584         return d_splice_alias(inode, dentry);
1585 }
1586 
1587 
1588 struct dentry *ext4_get_parent(struct dentry *child)
1589 {
1590         __u32 ino;
1591         static const struct qstr dotdot = QSTR_INIT("..", 2);
1592         struct ext4_dir_entry_2 * de;
1593         struct buffer_head *bh;
1594 
1595         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1596         if (IS_ERR(bh))
1597                 return (struct dentry *) bh;
1598         if (!bh)
1599                 return ERR_PTR(-ENOENT);
1600         ino = le32_to_cpu(de->inode);
1601         brelse(bh);
1602 
1603         if (!ext4_valid_inum(child->d_sb, ino)) {
1604                 EXT4_ERROR_INODE(d_inode(child),
1605                                  "bad parent inode number: %u", ino);
1606                 return ERR_PTR(-EFSCORRUPTED);
1607         }
1608 
1609         return d_obtain_alias(ext4_iget_normal(child->d_sb, ino));
1610 }
1611 
1612 /*
1613  * Move count entries from end of map between two memory locations.
1614  * Returns pointer to last entry moved.
1615  */
1616 static struct ext4_dir_entry_2 *
1617 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1618                 unsigned blocksize)
1619 {
1620         unsigned rec_len = 0;
1621 
1622         while (count--) {
1623                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1624                                                 (from + (map->offs<<2));
1625                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1626                 memcpy (to, de, rec_len);
1627                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1628                                 ext4_rec_len_to_disk(rec_len, blocksize);
1629                 de->inode = 0;
1630                 map++;
1631                 to += rec_len;
1632         }
1633         return (struct ext4_dir_entry_2 *) (to - rec_len);
1634 }
1635 
1636 /*
1637  * Compact each dir entry in the range to the minimal rec_len.
1638  * Returns pointer to last entry in range.
1639  */
1640 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1641 {
1642         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1643         unsigned rec_len = 0;
1644 
1645         prev = to = de;
1646         while ((char*)de < base + blocksize) {
1647                 next = ext4_next_entry(de, blocksize);
1648                 if (de->inode && de->name_len) {
1649                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1650                         if (de > to)
1651                                 memmove(to, de, rec_len);
1652                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1653                         prev = to;
1654                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1655                 }
1656                 de = next;
1657         }
1658         return prev;
1659 }
1660 
1661 /*
1662  * Split a full leaf block to make room for a new dir entry.
1663  * Allocate a new block, and move entries so that they are approx. equally full.
1664  * Returns pointer to de in block into which the new entry will be inserted.
1665  */
1666 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1667                         struct buffer_head **bh,struct dx_frame *frame,
1668                         struct dx_hash_info *hinfo)
1669 {
1670         unsigned blocksize = dir->i_sb->s_blocksize;
1671         unsigned count, continued;
1672         struct buffer_head *bh2;
1673         ext4_lblk_t newblock;
1674         u32 hash2;
1675         struct dx_map_entry *map;
1676         char *data1 = (*bh)->b_data, *data2;
1677         unsigned split, move, size;
1678         struct ext4_dir_entry_2 *de = NULL, *de2;
1679         struct ext4_dir_entry_tail *t;
1680         int     csum_size = 0;
1681         int     err = 0, i;
1682 
1683         if (ext4_has_metadata_csum(dir->i_sb))
1684                 csum_size = sizeof(struct ext4_dir_entry_tail);
1685 
1686         bh2 = ext4_append(handle, dir, &newblock);
1687         if (IS_ERR(bh2)) {
1688                 brelse(*bh);
1689                 *bh = NULL;
1690                 return (struct ext4_dir_entry_2 *) bh2;
1691         }
1692 
1693         BUFFER_TRACE(*bh, "get_write_access");
1694         err = ext4_journal_get_write_access(handle, *bh);
1695         if (err)
1696                 goto journal_error;
1697 
1698         BUFFER_TRACE(frame->bh, "get_write_access");
1699         err = ext4_journal_get_write_access(handle, frame->bh);
1700         if (err)
1701                 goto journal_error;
1702 
1703         data2 = bh2->b_data;
1704 
1705         /* create map in the end of data2 block */
1706         map = (struct dx_map_entry *) (data2 + blocksize);
1707         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1708                              blocksize, hinfo, map);
1709         map -= count;
1710         dx_sort_map(map, count);
1711         /* Split the existing block in the middle, size-wise */
1712         size = 0;
1713         move = 0;
1714         for (i = count-1; i >= 0; i--) {
1715                 /* is more than half of this entry in 2nd half of the block? */
1716                 if (size + map[i].size/2 > blocksize/2)
1717                         break;
1718                 size += map[i].size;
1719                 move++;
1720         }
1721         /* map index at which we will split */
1722         split = count - move;
1723         hash2 = map[split].hash;
1724         continued = hash2 == map[split - 1].hash;
1725         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1726                         (unsigned long)dx_get_block(frame->at),
1727                                         hash2, split, count-split));
1728 
1729         /* Fancy dance to stay within two buffers */
1730         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1731                               blocksize);
1732         de = dx_pack_dirents(data1, blocksize);
1733         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1734                                            (char *) de,
1735                                            blocksize);
1736         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1737                                             (char *) de2,
1738                                             blocksize);
1739         if (csum_size) {
1740                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1741                 initialize_dirent_tail(t, blocksize);
1742 
1743                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1744                 initialize_dirent_tail(t, blocksize);
1745         }
1746 
1747         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1748                         blocksize, 1));
1749         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1750                         blocksize, 1));
1751 
1752         /* Which block gets the new entry? */
1753         if (hinfo->hash >= hash2) {
1754                 swap(*bh, bh2);
1755                 de = de2;
1756         }
1757         dx_insert_block(frame, hash2 + continued, newblock);
1758         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1759         if (err)
1760                 goto journal_error;
1761         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1762         if (err)
1763                 goto journal_error;
1764         brelse(bh2);
1765         dxtrace(dx_show_index("frame", frame->entries));
1766         return de;
1767 
1768 journal_error:
1769         brelse(*bh);
1770         brelse(bh2);
1771         *bh = NULL;
1772         ext4_std_error(dir->i_sb, err);
1773         return ERR_PTR(err);
1774 }
1775 
1776 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1777                       struct buffer_head *bh,
1778                       void *buf, int buf_size,
1779                       struct ext4_filename *fname,
1780                       struct ext4_dir_entry_2 **dest_de)
1781 {
1782         struct ext4_dir_entry_2 *de;
1783         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1784         int nlen, rlen;
1785         unsigned int offset = 0;
1786         char *top;
1787 
1788         de = (struct ext4_dir_entry_2 *)buf;
1789         top = buf + buf_size - reclen;
1790         while ((char *) de <= top) {
1791                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1792                                          buf, buf_size, offset))
1793                         return -EFSCORRUPTED;
1794                 if (ext4_match(fname, de))
1795                         return -EEXIST;
1796                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1797                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1798                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1799                         break;
1800                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1801                 offset += rlen;
1802         }
1803         if ((char *) de > top)
1804                 return -ENOSPC;
1805 
1806         *dest_de = de;
1807         return 0;
1808 }
1809 
1810 void ext4_insert_dentry(struct inode *inode,
1811                         struct ext4_dir_entry_2 *de,
1812                         int buf_size,
1813                         struct ext4_filename *fname)
1814 {
1815 
1816         int nlen, rlen;
1817 
1818         nlen = EXT4_DIR_REC_LEN(de->name_len);
1819         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1820         if (de->inode) {
1821                 struct ext4_dir_entry_2 *de1 =
1822                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1823                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1824                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1825                 de = de1;
1826         }
1827         de->file_type = EXT4_FT_UNKNOWN;
1828         de->inode = cpu_to_le32(inode->i_ino);
1829         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1830         de->name_len = fname_len(fname);
1831         memcpy(de->name, fname_name(fname), fname_len(fname));
1832 }
1833 
1834 /*
1835  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1836  * it points to a directory entry which is guaranteed to be large
1837  * enough for new directory entry.  If de is NULL, then
1838  * add_dirent_to_buf will attempt search the directory block for
1839  * space.  It will return -ENOSPC if no space is available, and -EIO
1840  * and -EEXIST if directory entry already exists.
1841  */
1842 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1843                              struct inode *dir,
1844                              struct inode *inode, struct ext4_dir_entry_2 *de,
1845                              struct buffer_head *bh)
1846 {
1847         unsigned int    blocksize = dir->i_sb->s_blocksize;
1848         int             csum_size = 0;
1849         int             err;
1850 
1851         if (ext4_has_metadata_csum(inode->i_sb))
1852                 csum_size = sizeof(struct ext4_dir_entry_tail);
1853 
1854         if (!de) {
1855                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1856                                         blocksize - csum_size, fname, &de);
1857                 if (err)
1858                         return err;
1859         }
1860         BUFFER_TRACE(bh, "get_write_access");
1861         err = ext4_journal_get_write_access(handle, bh);
1862         if (err) {
1863                 ext4_std_error(dir->i_sb, err);
1864                 return err;
1865         }
1866 
1867         /* By now the buffer is marked for journaling */
1868         ext4_insert_dentry(inode, de, blocksize, fname);
1869 
1870         /*
1871          * XXX shouldn't update any times until successful
1872          * completion of syscall, but too many callers depend
1873          * on this.
1874          *
1875          * XXX similarly, too many callers depend on
1876          * ext4_new_inode() setting the times, but error
1877          * recovery deletes the inode, so the worst that can
1878          * happen is that the times are slightly out of date
1879          * and/or different from the directory change time.
1880          */
1881         dir->i_mtime = dir->i_ctime = current_time(dir);
1882         ext4_update_dx_flag(dir);
1883         inode_inc_iversion(dir);
1884         ext4_mark_inode_dirty(handle, dir);
1885         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1886         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1887         if (err)
1888                 ext4_std_error(dir->i_sb, err);
1889         return 0;
1890 }
1891 
1892 /*
1893  * This converts a one block unindexed directory to a 3 block indexed
1894  * directory, and adds the dentry to the indexed directory.
1895  */
1896 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1897                             struct inode *dir,
1898                             struct inode *inode, struct buffer_head *bh)
1899 {
1900         struct buffer_head *bh2;
1901         struct dx_root  *root;
1902         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1903         struct dx_entry *entries;
1904         struct ext4_dir_entry_2 *de, *de2;
1905         struct ext4_dir_entry_tail *t;
1906         char            *data1, *top;
1907         unsigned        len;
1908         int             retval;
1909         unsigned        blocksize;
1910         ext4_lblk_t  block;
1911         struct fake_dirent *fde;
1912         int csum_size = 0;
1913 
1914         if (ext4_has_metadata_csum(inode->i_sb))
1915                 csum_size = sizeof(struct ext4_dir_entry_tail);
1916 
1917         blocksize =  dir->i_sb->s_blocksize;
1918         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1919         BUFFER_TRACE(bh, "get_write_access");
1920         retval = ext4_journal_get_write_access(handle, bh);
1921         if (retval) {
1922                 ext4_std_error(dir->i_sb, retval);
1923                 brelse(bh);
1924                 return retval;
1925         }
1926         root = (struct dx_root *) bh->b_data;
1927 
1928         /* The 0th block becomes the root, move the dirents out */
1929         fde = &root->dotdot;
1930         de = (struct ext4_dir_entry_2 *)((char *)fde +
1931                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1932         if ((char *) de >= (((char *) root) + blocksize)) {
1933                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1934                 brelse(bh);
1935                 return -EFSCORRUPTED;
1936         }
1937         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1938 
1939         /* Allocate new block for the 0th block's dirents */
1940         bh2 = ext4_append(handle, dir, &block);
1941         if (IS_ERR(bh2)) {
1942                 brelse(bh);
1943                 return PTR_ERR(bh2);
1944         }
1945         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1946         data1 = bh2->b_data;
1947 
1948         memcpy (data1, de, len);
1949         de = (struct ext4_dir_entry_2 *) data1;
1950         top = data1 + len;
1951         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1952                 de = de2;
1953         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1954                                            (char *) de,
1955                                            blocksize);
1956 
1957         if (csum_size) {
1958                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1959                 initialize_dirent_tail(t, blocksize);
1960         }
1961 
1962         /* Initialize the root; the dot dirents already exist */
1963         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1964         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
1965                                            blocksize);
1966         memset (&root->info, 0, sizeof(root->info));
1967         root->info.info_length = sizeof(root->info);
1968         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1969         entries = root->entries;
1970         dx_set_block(entries, 1);
1971         dx_set_count(entries, 1);
1972         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
1973 
1974         /* Initialize as for dx_probe */
1975         fname->hinfo.hash_version = root->info.hash_version;
1976         if (fname->hinfo.hash_version <= DX_HASH_TEA)
1977                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
1978         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1979         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
1980 
1981         memset(frames, 0, sizeof(frames));
1982         frame = frames;
1983         frame->entries = entries;
1984         frame->at = entries;
1985         frame->bh = bh;
1986 
1987         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1988         if (retval)
1989                 goto out_frames;        
1990         retval = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1991         if (retval)
1992                 goto out_frames;        
1993 
1994         de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
1995         if (IS_ERR(de)) {
1996                 retval = PTR_ERR(de);
1997                 goto out_frames;
1998         }
1999 
2000         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2001 out_frames:
2002         /*
2003          * Even if the block split failed, we have to properly write
2004          * out all the changes we did so far. Otherwise we can end up
2005          * with corrupted filesystem.
2006          */
2007         if (retval)
2008                 ext4_mark_inode_dirty(handle, dir);
2009         dx_release(frames);
2010         brelse(bh2);
2011         return retval;
2012 }
2013 
2014 /*
2015  *      ext4_add_entry()
2016  *
2017  * adds a file entry to the specified directory, using the same
2018  * semantics as ext4_find_entry(). It returns NULL if it failed.
2019  *
2020  * NOTE!! The inode part of 'de' is left at 0 - which means you
2021  * may not sleep between calling this and putting something into
2022  * the entry, as someone else might have used it while you slept.
2023  */
2024 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2025                           struct inode *inode)
2026 {
2027         struct inode *dir = d_inode(dentry->d_parent);
2028         struct buffer_head *bh = NULL;
2029         struct ext4_dir_entry_2 *de;
2030         struct ext4_dir_entry_tail *t;
2031         struct super_block *sb;
2032         struct ext4_filename fname;
2033         int     retval;
2034         int     dx_fallback=0;
2035         unsigned blocksize;
2036         ext4_lblk_t block, blocks;
2037         int     csum_size = 0;
2038 
2039         if (ext4_has_metadata_csum(inode->i_sb))
2040                 csum_size = sizeof(struct ext4_dir_entry_tail);
2041 
2042         sb = dir->i_sb;
2043         blocksize = sb->s_blocksize;
2044         if (!dentry->d_name.len)
2045                 return -EINVAL;
2046 
2047         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2048         if (retval)
2049                 return retval;
2050 
2051         if (ext4_has_inline_data(dir)) {
2052                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2053                 if (retval < 0)
2054                         goto out;
2055                 if (retval == 1) {
2056                         retval = 0;
2057                         goto out;
2058                 }
2059         }
2060 
2061         if (is_dx(dir)) {
2062                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2063                 if (!retval || (retval != ERR_BAD_DX_DIR))
2064                         goto out;
2065                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2066                 dx_fallback++;
2067                 ext4_mark_inode_dirty(handle, dir);
2068         }
2069         blocks = dir->i_size >> sb->s_blocksize_bits;
2070         for (block = 0; block < blocks; block++) {
2071                 bh = ext4_read_dirblock(dir, block, DIRENT);
2072                 if (IS_ERR(bh)) {
2073                         retval = PTR_ERR(bh);
2074                         bh = NULL;
2075                         goto out;
2076                 }
2077                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2078                                            NULL, bh);
2079                 if (retval != -ENOSPC)
2080                         goto out;
2081 
2082                 if (blocks == 1 && !dx_fallback &&
2083                     ext4_has_feature_dir_index(sb)) {
2084                         retval = make_indexed_dir(handle, &fname, dir,
2085                                                   inode, bh);
2086                         bh = NULL; /* make_indexed_dir releases bh */
2087                         goto out;
2088                 }
2089                 brelse(bh);
2090         }
2091         bh = ext4_append(handle, dir, &block);
2092         if (IS_ERR(bh)) {
2093                 retval = PTR_ERR(bh);
2094                 bh = NULL;
2095                 goto out;
2096         }
2097         de = (struct ext4_dir_entry_2 *) bh->b_data;
2098         de->inode = 0;
2099         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2100 
2101         if (csum_size) {
2102                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2103                 initialize_dirent_tail(t, blocksize);
2104         }
2105 
2106         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2107 out:
2108         ext4_fname_free_filename(&fname);
2109         brelse(bh);
2110         if (retval == 0)
2111                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2112         return retval;
2113 }
2114 
2115 /*
2116  * Returns 0 for success, or a negative error value
2117  */
2118 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2119                              struct inode *dir, struct inode *inode)
2120 {
2121         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2122         struct dx_entry *entries, *at;
2123         struct buffer_head *bh;
2124         struct super_block *sb = dir->i_sb;
2125         struct ext4_dir_entry_2 *de;
2126         int restart;
2127         int err;
2128 
2129 again:
2130         restart = 0;
2131         frame = dx_probe(fname, dir, NULL, frames);
2132         if (IS_ERR(frame))
2133                 return PTR_ERR(frame);
2134         entries = frame->entries;
2135         at = frame->at;
2136         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2137         if (IS_ERR(bh)) {
2138                 err = PTR_ERR(bh);
2139                 bh = NULL;
2140                 goto cleanup;
2141         }
2142 
2143         BUFFER_TRACE(bh, "get_write_access");
2144         err = ext4_journal_get_write_access(handle, bh);
2145         if (err)
2146                 goto journal_error;
2147 
2148         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2149         if (err != -ENOSPC)
2150                 goto cleanup;
2151 
2152         err = 0;
2153         /* Block full, should compress but for now just split */
2154         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2155                        dx_get_count(entries), dx_get_limit(entries)));
2156         /* Need to split index? */
2157         if (dx_get_count(entries) == dx_get_limit(entries)) {
2158                 ext4_lblk_t newblock;
2159                 int levels = frame - frames + 1;
2160                 unsigned int icount;
2161                 int add_level = 1;
2162                 struct dx_entry *entries2;
2163                 struct dx_node *node2;
2164                 struct buffer_head *bh2;
2165 
2166                 while (frame > frames) {
2167                         if (dx_get_count((frame - 1)->entries) <
2168                             dx_get_limit((frame - 1)->entries)) {
2169                                 add_level = 0;
2170                                 break;
2171                         }
2172                         frame--; /* split higher index block */
2173                         at = frame->at;
2174                         entries = frame->entries;
2175                         restart = 1;
2176                 }
2177                 if (add_level && levels == ext4_dir_htree_level(sb)) {
2178                         ext4_warning(sb, "Directory (ino: %lu) index full, "
2179                                          "reach max htree level :%d",
2180                                          dir->i_ino, levels);
2181                         if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
2182                                 ext4_warning(sb, "Large directory feature is "
2183                                                  "not enabled on this "
2184                                                  "filesystem");
2185                         }
2186                         err = -ENOSPC;
2187                         goto cleanup;
2188                 }
2189                 icount = dx_get_count(entries);
2190                 bh2 = ext4_append(handle, dir, &newblock);
2191                 if (IS_ERR(bh2)) {
2192                         err = PTR_ERR(bh2);
2193                         goto cleanup;
2194                 }
2195                 node2 = (struct dx_node *)(bh2->b_data);
2196                 entries2 = node2->entries;
2197                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2198                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2199                                                            sb->s_blocksize);
2200                 BUFFER_TRACE(frame->bh, "get_write_access");
2201                 err = ext4_journal_get_write_access(handle, frame->bh);
2202                 if (err)
2203                         goto journal_error;
2204                 if (!add_level) {
2205                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2206                         unsigned hash2 = dx_get_hash(entries + icount1);
2207                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2208                                        icount1, icount2));
2209 
2210                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2211                         err = ext4_journal_get_write_access(handle,
2212                                                              (frame - 1)->bh);
2213                         if (err)
2214                                 goto journal_error;
2215 
2216                         memcpy((char *) entries2, (char *) (entries + icount1),
2217                                icount2 * sizeof(struct dx_entry));
2218                         dx_set_count(entries, icount1);
2219                         dx_set_count(entries2, icount2);
2220                         dx_set_limit(entries2, dx_node_limit(dir));
2221 
2222                         /* Which index block gets the new entry? */
2223                         if (at - entries >= icount1) {
2224                                 frame->at = at = at - entries - icount1 + entries2;
2225                                 frame->entries = entries = entries2;
2226                                 swap(frame->bh, bh2);
2227                         }
2228                         dx_insert_block((frame - 1), hash2, newblock);
2229                         dxtrace(dx_show_index("node", frame->entries));
2230                         dxtrace(dx_show_index("node",
2231                                ((struct dx_node *) bh2->b_data)->entries));
2232                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2233                         if (err)
2234                                 goto journal_error;
2235                         brelse (bh2);
2236                         err = ext4_handle_dirty_dx_node(handle, dir,
2237                                                    (frame - 1)->bh);
2238                         if (err)
2239                                 goto journal_error;
2240                         if (restart) {
2241                                 err = ext4_handle_dirty_dx_node(handle, dir,
2242                                                            frame->bh);
2243                                 goto journal_error;
2244                         }
2245                 } else {
2246                         struct dx_root *dxroot;
2247                         memcpy((char *) entries2, (char *) entries,
2248                                icount * sizeof(struct dx_entry));
2249                         dx_set_limit(entries2, dx_node_limit(dir));
2250 
2251                         /* Set up root */
2252                         dx_set_count(entries, 1);
2253                         dx_set_block(entries + 0, newblock);
2254                         dxroot = (struct dx_root *)frames[0].bh->b_data;
2255                         dxroot->info.indirect_levels += 1;
2256                         dxtrace(printk(KERN_DEBUG
2257                                        "Creating %d level index...\n",
2258                                        info->indirect_levels));
2259                         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2260                         if (err)
2261                                 goto journal_error;
2262                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2263                         brelse(bh2);
2264                         restart = 1;
2265                         goto journal_error;
2266                 }
2267         }
2268         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2269         if (IS_ERR(de)) {
2270                 err = PTR_ERR(de);
2271                 goto cleanup;
2272         }
2273         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2274         goto cleanup;
2275 
2276 journal_error:
2277         ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
2278 cleanup:
2279         brelse(bh);
2280         dx_release(frames);
2281         /* @restart is true means htree-path has been changed, we need to
2282          * repeat dx_probe() to find out valid htree-path
2283          */
2284         if (restart && err == 0)
2285                 goto again;
2286         return err;
2287 }
2288 
2289 /*
2290  * ext4_generic_delete_entry deletes a directory entry by merging it
2291  * with the previous entry
2292  */
2293 int ext4_generic_delete_entry(handle_t *handle,
2294                               struct inode *dir,
2295                               struct ext4_dir_entry_2 *de_del,
2296                               struct buffer_head *bh,
2297                               void *entry_buf,
2298                               int buf_size,
2299                               int csum_size)
2300 {
2301         struct ext4_dir_entry_2 *de, *pde;
2302         unsigned int blocksize = dir->i_sb->s_blocksize;
2303         int i;
2304 
2305         i = 0;
2306         pde = NULL;
2307         de = (struct ext4_dir_entry_2 *)entry_buf;
2308         while (i < buf_size - csum_size) {
2309                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2310                                          bh->b_data, bh->b_size, i))
2311                         return -EFSCORRUPTED;
2312                 if (de == de_del)  {
2313                         if (pde)
2314                                 pde->rec_len = ext4_rec_len_to_disk(
2315                                         ext4_rec_len_from_disk(pde->rec_len,
2316                                                                blocksize) +
2317                                         ext4_rec_len_from_disk(de->rec_len,
2318                                                                blocksize),
2319                                         blocksize);
2320                         else
2321                                 de->inode = 0;
2322                         inode_inc_iversion(dir);
2323                         return 0;
2324                 }
2325                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2326                 pde = de;
2327                 de = ext4_next_entry(de, blocksize);
2328         }
2329         return -ENOENT;
2330 }
2331 
2332 static int ext4_delete_entry(handle_t *handle,
2333                              struct inode *dir,
2334                              struct ext4_dir_entry_2 *de_del,
2335                              struct buffer_head *bh)
2336 {
2337         int err, csum_size = 0;
2338 
2339         if (ext4_has_inline_data(dir)) {
2340                 int has_inline_data = 1;
2341                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2342                                                &has_inline_data);
2343                 if (has_inline_data)
2344                         return err;
2345         }
2346 
2347         if (ext4_has_metadata_csum(dir->i_sb))
2348                 csum_size = sizeof(struct ext4_dir_entry_tail);
2349 
2350         BUFFER_TRACE(bh, "get_write_access");
2351         err = ext4_journal_get_write_access(handle, bh);
2352         if (unlikely(err))
2353                 goto out;
2354 
2355         err = ext4_generic_delete_entry(handle, dir, de_del,
2356                                         bh, bh->b_data,
2357                                         dir->i_sb->s_blocksize, csum_size);
2358         if (err)
2359                 goto out;
2360 
2361         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2362         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2363         if (unlikely(err))
2364                 goto out;
2365 
2366         return 0;
2367 out:
2368         if (err != -ENOENT)
2369                 ext4_std_error(dir->i_sb, err);
2370         return err;
2371 }
2372 
2373 /*
2374  * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
2375  * since this indicates that nlinks count was previously 1 to avoid overflowing
2376  * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
2377  * that subdirectory link counts are not being maintained accurately.
2378  *
2379  * The caller has already checked for i_nlink overflow in case the DIR_LINK
2380  * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
2381  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
2382  * on regular files) and to avoid creating huge/slow non-HTREE directories.
2383  */
2384 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2385 {
2386         inc_nlink(inode);
2387         if (is_dx(inode) &&
2388             (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
2389                 set_nlink(inode, 1);
2390 }
2391 
2392 /*
2393  * If a directory had nlink == 1, then we should let it be 1. This indicates
2394  * directory has >EXT4_LINK_MAX subdirs.
2395  */
2396 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2397 {
2398         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2399                 drop_nlink(inode);
2400 }
2401 
2402 
2403 static int ext4_add_nondir(handle_t *handle,
2404                 struct dentry *dentry, struct inode *inode)
2405 {
2406         int err = ext4_add_entry(handle, dentry, inode);
2407         if (!err) {
2408                 ext4_mark_inode_dirty(handle, inode);
2409                 unlock_new_inode(inode);
2410                 d_instantiate(dentry, inode);
2411                 return 0;
2412         }
2413         drop_nlink(inode);
2414         unlock_new_inode(inode);
2415         iput(inode);
2416         return err;
2417 }
2418 
2419 /*
2420  * By the time this is called, we already have created
2421  * the directory cache entry for the new file, but it
2422  * is so far negative - it has no inode.
2423  *
2424  * If the create succeeds, we fill in the inode information
2425  * with d_instantiate().
2426  */
2427 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2428                        bool excl)
2429 {
2430         handle_t *handle;
2431         struct inode *inode;
2432         int err, credits, retries = 0;
2433 
2434         err = dquot_initialize(dir);
2435         if (err)
2436                 return err;
2437 
2438         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2439                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2440 retry:
2441         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2442                                             NULL, EXT4_HT_DIR, credits);
2443         handle = ext4_journal_current_handle();
2444         err = PTR_ERR(inode);
2445         if (!IS_ERR(inode)) {
2446                 inode->i_op = &ext4_file_inode_operations;
2447                 inode->i_fop = &ext4_file_operations;
2448                 ext4_set_aops(inode);
2449                 err = ext4_add_nondir(handle, dentry, inode);
2450                 if (!err && IS_DIRSYNC(dir))
2451                         ext4_handle_sync(handle);
2452         }
2453         if (handle)
2454                 ext4_journal_stop(handle);
2455         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2456                 goto retry;
2457         return err;
2458 }
2459 
2460 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2461                       umode_t mode, dev_t rdev)
2462 {
2463         handle_t *handle;
2464         struct inode *inode;
2465         int err, credits, retries = 0;
2466 
2467         err = dquot_initialize(dir);
2468         if (err)
2469                 return err;
2470 
2471         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2472                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2473 retry:
2474         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2475                                             NULL, EXT4_HT_DIR, credits);
2476         handle = ext4_journal_current_handle();
2477         err = PTR_ERR(inode);
2478         if (!IS_ERR(inode)) {
2479                 init_special_inode(inode, inode->i_mode, rdev);
2480                 inode->i_op = &ext4_special_inode_operations;
2481                 err = ext4_add_nondir(handle, dentry, inode);
2482                 if (!err && IS_DIRSYNC(dir))
2483                         ext4_handle_sync(handle);
2484         }
2485         if (handle)
2486                 ext4_journal_stop(handle);
2487         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2488                 goto retry;
2489         return err;
2490 }
2491 
2492 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2493 {
2494         handle_t *handle;
2495         struct inode *inode;
2496         int err, retries = 0;
2497 
2498         err = dquot_initialize(dir);
2499         if (err)
2500                 return err;
2501 
2502 retry:
2503         inode = ext4_new_inode_start_handle(dir, mode,
2504                                             NULL, 0, NULL,
2505                                             EXT4_HT_DIR,
2506                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2507                           4 + EXT4_XATTR_TRANS_BLOCKS);
2508         handle = ext4_journal_current_handle();
2509         err = PTR_ERR(inode);
2510         if (!IS_ERR(inode)) {
2511                 inode->i_op = &ext4_file_inode_operations;
2512                 inode->i_fop = &ext4_file_operations;
2513                 ext4_set_aops(inode);
2514                 d_tmpfile(dentry, inode);
2515                 err = ext4_orphan_add(handle, inode);
2516                 if (err)
2517                         goto err_unlock_inode;
2518                 mark_inode_dirty(inode);
2519                 unlock_new_inode(inode);
2520         }
2521         if (handle)
2522                 ext4_journal_stop(handle);
2523         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2524                 goto retry;
2525         return err;
2526 err_unlock_inode:
2527         ext4_journal_stop(handle);
2528         unlock_new_inode(inode);
2529         return err;
2530 }
2531 
2532 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2533                           struct ext4_dir_entry_2 *de,
2534                           int blocksize, int csum_size,
2535                           unsigned int parent_ino, int dotdot_real_len)
2536 {
2537         de->inode = cpu_to_le32(inode->i_ino);
2538         de->name_len = 1;
2539         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2540                                            blocksize);
2541         strcpy(de->name, ".");
2542         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2543 
2544         de = ext4_next_entry(de, blocksize);
2545         de->inode = cpu_to_le32(parent_ino);
2546         de->name_len = 2;
2547         if (!dotdot_real_len)
2548                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2549                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2550                                         blocksize);
2551         else
2552                 de->rec_len = ext4_rec_len_to_disk(
2553                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2554         strcpy(de->name, "..");
2555         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2556 
2557         return ext4_next_entry(de, blocksize);
2558 }
2559 
2560 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2561                              struct inode *inode)
2562 {
2563         struct buffer_head *dir_block = NULL;
2564         struct ext4_dir_entry_2 *de;
2565         struct ext4_dir_entry_tail *t;
2566         ext4_lblk_t block = 0;
2567         unsigned int blocksize = dir->i_sb->s_blocksize;
2568         int csum_size = 0;
2569         int err;
2570 
2571         if (ext4_has_metadata_csum(dir->i_sb))
2572                 csum_size = sizeof(struct ext4_dir_entry_tail);
2573 
2574         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2575                 err = ext4_try_create_inline_dir(handle, dir, inode);
2576                 if (err < 0 && err != -ENOSPC)
2577                         goto out;
2578                 if (!err)
2579                         goto out;
2580         }
2581 
2582         inode->i_size = 0;
2583         dir_block = ext4_append(handle, inode, &block);
2584         if (IS_ERR(dir_block))
2585                 return PTR_ERR(dir_block);
2586         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2587         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2588         set_nlink(inode, 2);
2589         if (csum_size) {
2590                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2591                 initialize_dirent_tail(t, blocksize);
2592         }
2593 
2594         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2595         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2596         if (err)
2597                 goto out;
2598         set_buffer_verified(dir_block);
2599 out:
2600         brelse(dir_block);
2601         return err;
2602 }
2603 
2604 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2605 {
2606         handle_t *handle;
2607         struct inode *inode;
2608         int err, credits, retries = 0;
2609 
2610         if (EXT4_DIR_LINK_MAX(dir))
2611                 return -EMLINK;
2612 
2613         err = dquot_initialize(dir);
2614         if (err)
2615                 return err;
2616 
2617         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2618                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2619 retry:
2620         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2621                                             &dentry->d_name,
2622                                             0, NULL, EXT4_HT_DIR, credits);
2623         handle = ext4_journal_current_handle();
2624         err = PTR_ERR(inode);
2625         if (IS_ERR(inode))
2626                 goto out_stop;
2627 
2628         inode->i_op = &ext4_dir_inode_operations;
2629         inode->i_fop = &ext4_dir_operations;
2630         err = ext4_init_new_dir(handle, dir, inode);
2631         if (err)
2632                 goto out_clear_inode;
2633         err = ext4_mark_inode_dirty(handle, inode);
2634         if (!err)
2635                 err = ext4_add_entry(handle, dentry, inode);
2636         if (err) {
2637 out_clear_inode:
2638                 clear_nlink(inode);
2639                 unlock_new_inode(inode);
2640                 ext4_mark_inode_dirty(handle, inode);
2641                 iput(inode);
2642                 goto out_stop;
2643         }
2644         ext4_inc_count(handle, dir);
2645         ext4_update_dx_flag(dir);
2646         err = ext4_mark_inode_dirty(handle, dir);
2647         if (err)
2648                 goto out_clear_inode;
2649         unlock_new_inode(inode);
2650         d_instantiate(dentry, inode);
2651         if (IS_DIRSYNC(dir))
2652                 ext4_handle_sync(handle);
2653 
2654 out_stop:
2655         if (handle)
2656                 ext4_journal_stop(handle);
2657         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2658                 goto retry;
2659         return err;
2660 }
2661 
2662 /*
2663  * routine to check that the specified directory is empty (for rmdir)
2664  */
2665 bool ext4_empty_dir(struct inode *inode)
2666 {
2667         unsigned int offset;
2668         struct buffer_head *bh;
2669         struct ext4_dir_entry_2 *de, *de1;
2670         struct super_block *sb;
2671 
2672         if (ext4_has_inline_data(inode)) {
2673                 int has_inline_data = 1;
2674                 int ret;
2675 
2676                 ret = empty_inline_dir(inode, &has_inline_data);
2677                 if (has_inline_data)
2678                         return ret;
2679         }
2680 
2681         sb = inode->i_sb;
2682         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2683                 EXT4_ERROR_INODE(inode, "invalid size");
2684                 return true;
2685         }
2686         bh = ext4_read_dirblock(inode, 0, EITHER);
2687         if (IS_ERR(bh))
2688                 return true;
2689 
2690         de = (struct ext4_dir_entry_2 *) bh->b_data;
2691         de1 = ext4_next_entry(de, sb->s_blocksize);
2692         if (le32_to_cpu(de->inode) != inode->i_ino ||
2693                         le32_to_cpu(de1->inode) == 0 ||
2694                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2695                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2696                 brelse(bh);
2697                 return true;
2698         }
2699         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2700                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2701         de = ext4_next_entry(de1, sb->s_blocksize);
2702         while (offset < inode->i_size) {
2703                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2704                         unsigned int lblock;
2705                         brelse(bh);
2706                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2707                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2708                         if (IS_ERR(bh))
2709                                 return true;
2710                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2711                 }
2712                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2713                                          bh->b_data, bh->b_size, offset)) {
2714                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2715                                                          sb->s_blocksize);
2716                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2717                         continue;
2718                 }
2719                 if (le32_to_cpu(de->inode)) {
2720                         brelse(bh);
2721                         return false;
2722                 }
2723                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2724                 de = ext4_next_entry(de, sb->s_blocksize);
2725         }
2726         brelse(bh);
2727         return true;
2728 }
2729 
2730 /*
2731  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2732  * such inodes, starting at the superblock, in case we crash before the
2733  * file is closed/deleted, or in case the inode truncate spans multiple
2734  * transactions and the last transaction is not recovered after a crash.
2735  *
2736  * At filesystem recovery time, we walk this list deleting unlinked
2737  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2738  *
2739  * Orphan list manipulation functions must be called under i_mutex unless
2740  * we are just creating the inode or deleting it.
2741  */
2742 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2743 {
2744         struct super_block *sb = inode->i_sb;
2745         struct ext4_sb_info *sbi = EXT4_SB(sb);
2746         struct ext4_iloc iloc;
2747         int err = 0, rc;
2748         bool dirty = false;
2749 
2750         if (!sbi->s_journal || is_bad_inode(inode))
2751                 return 0;
2752 
2753         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2754                      !inode_is_locked(inode));
2755         /*
2756          * Exit early if inode already is on orphan list. This is a big speedup
2757          * since we don't have to contend on the global s_orphan_lock.
2758          */
2759         if (!list_empty(&EXT4_I(inode)->i_orphan))
2760                 return 0;
2761 
2762         /*
2763          * Orphan handling is only valid for files with data blocks
2764          * being truncated, or files being unlinked. Note that we either
2765          * hold i_mutex, or the inode can not be referenced from outside,
2766          * so i_nlink should not be bumped due to race
2767          */
2768         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2769                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2770 
2771         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2772         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2773         if (err)
2774                 goto out;
2775 
2776         err = ext4_reserve_inode_write(handle, inode, &iloc);
2777         if (err)
2778                 goto out;
2779 
2780         mutex_lock(&sbi->s_orphan_lock);
2781         /*
2782          * Due to previous errors inode may be already a part of on-disk
2783          * orphan list. If so skip on-disk list modification.
2784          */
2785         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2786             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2787                 /* Insert this inode at the head of the on-disk orphan list */
2788                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2789                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2790                 dirty = true;
2791         }
2792         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2793         mutex_unlock(&sbi->s_orphan_lock);
2794 
2795         if (dirty) {
2796                 err = ext4_handle_dirty_super(handle, sb);
2797                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2798                 if (!err)
2799                         err = rc;
2800                 if (err) {
2801                         /*
2802                          * We have to remove inode from in-memory list if
2803                          * addition to on disk orphan list failed. Stray orphan
2804                          * list entries can cause panics at unmount time.
2805                          */
2806                         mutex_lock(&sbi->s_orphan_lock);
2807                         list_del_init(&EXT4_I(inode)->i_orphan);
2808                         mutex_unlock(&sbi->s_orphan_lock);
2809                 }
2810         }
2811         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2812         jbd_debug(4, "orphan inode %lu will point to %d\n",
2813                         inode->i_ino, NEXT_ORPHAN(inode));
2814 out:
2815         ext4_std_error(sb, err);
2816         return err;
2817 }
2818 
2819 /*
2820  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2821  * of such inodes stored on disk, because it is finally being cleaned up.
2822  */
2823 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2824 {
2825         struct list_head *prev;
2826         struct ext4_inode_info *ei = EXT4_I(inode);
2827         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2828         __u32 ino_next;
2829         struct ext4_iloc iloc;
2830         int err = 0;
2831 
2832         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2833                 return 0;
2834 
2835         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2836                      !inode_is_locked(inode));
2837         /* Do this quick check before taking global s_orphan_lock. */
2838         if (list_empty(&ei->i_orphan))
2839                 return 0;
2840 
2841         if (handle) {
2842                 /* Grab inode buffer early before taking global s_orphan_lock */
2843                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2844         }
2845 
2846         mutex_lock(&sbi->s_orphan_lock);
2847         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2848 
2849         prev = ei->i_orphan.prev;
2850         list_del_init(&ei->i_orphan);
2851 
2852         /* If we're on an error path, we may not have a valid
2853          * transaction handle with which to update the orphan list on
2854          * disk, but we still need to remove the inode from the linked
2855          * list in memory. */
2856         if (!handle || err) {
2857                 mutex_unlock(&sbi->s_orphan_lock);
2858                 goto out_err;
2859         }
2860 
2861         ino_next = NEXT_ORPHAN(inode);
2862         if (prev == &sbi->s_orphan) {
2863                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2864                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2865                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2866                 if (err) {
2867                         mutex_unlock(&sbi->s_orphan_lock);
2868                         goto out_brelse;
2869                 }
2870                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2871                 mutex_unlock(&sbi->s_orphan_lock);
2872                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2873         } else {
2874                 struct ext4_iloc iloc2;
2875                 struct inode *i_prev =
2876                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2877 
2878                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2879                           i_prev->i_ino, ino_next);
2880                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2881                 if (err) {
2882                         mutex_unlock(&sbi->s_orphan_lock);
2883                         goto out_brelse;
2884                 }
2885                 NEXT_ORPHAN(i_prev) = ino_next;
2886                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2887                 mutex_unlock(&sbi->s_orphan_lock);
2888         }
2889         if (err)
2890                 goto out_brelse;
2891         NEXT_ORPHAN(inode) = 0;
2892         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2893 out_err:
2894         ext4_std_error(inode->i_sb, err);
2895         return err;
2896 
2897 out_brelse:
2898         brelse(iloc.bh);
2899         goto out_err;
2900 }
2901 
2902 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2903 {
2904         int retval;
2905         struct inode *inode;
2906         struct buffer_head *bh;
2907         struct ext4_dir_entry_2 *de;
2908         handle_t *handle = NULL;
2909 
2910         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2911                 return -EIO;
2912 
2913         /* Initialize quotas before so that eventual writes go in
2914          * separate transaction */
2915         retval = dquot_initialize(dir);
2916         if (retval)
2917                 return retval;
2918         retval = dquot_initialize(d_inode(dentry));
2919         if (retval)
2920                 return retval;
2921 
2922         retval = -ENOENT;
2923         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2924         if (IS_ERR(bh))
2925                 return PTR_ERR(bh);
2926         if (!bh)
2927                 goto end_rmdir;
2928 
2929         inode = d_inode(dentry);
2930 
2931         retval = -EFSCORRUPTED;
2932         if (le32_to_cpu(de->inode) != inode->i_ino)
2933                 goto end_rmdir;
2934 
2935         retval = -ENOTEMPTY;
2936         if (!ext4_empty_dir(inode))
2937                 goto end_rmdir;
2938 
2939         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2940                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2941         if (IS_ERR(handle)) {
2942                 retval = PTR_ERR(handle);
2943                 handle = NULL;
2944                 goto end_rmdir;
2945         }
2946 
2947         if (IS_DIRSYNC(dir))
2948                 ext4_handle_sync(handle);
2949 
2950         retval = ext4_delete_entry(handle, dir, de, bh);
2951         if (retval)
2952                 goto end_rmdir;
2953         if (!EXT4_DIR_LINK_EMPTY(inode))
2954                 ext4_warning_inode(inode,
2955                              "empty directory '%.*s' has too many links (%u)",
2956                              dentry->d_name.len, dentry->d_name.name,
2957                              inode->i_nlink);
2958         inode->i_version++;
2959         clear_nlink(inode);
2960         /* There's no need to set i_disksize: the fact that i_nlink is
2961          * zero will ensure that the right thing happens during any
2962          * recovery. */
2963         inode->i_size = 0;
2964         ext4_orphan_add(handle, inode);
2965         inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2966         ext4_mark_inode_dirty(handle, inode);
2967         ext4_dec_count(handle, dir);
2968         ext4_update_dx_flag(dir);
2969         ext4_mark_inode_dirty(handle, dir);
2970 
2971 end_rmdir:
2972         brelse(bh);
2973         if (handle)
2974                 ext4_journal_stop(handle);
2975         return retval;
2976 }
2977 
2978 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2979 {
2980         int retval;
2981         struct inode *inode;
2982         struct buffer_head *bh;
2983         struct ext4_dir_entry_2 *de;
2984         handle_t *handle = NULL;
2985 
2986         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2987                 return -EIO;
2988 
2989         trace_ext4_unlink_enter(dir, dentry);
2990         /* Initialize quotas before so that eventual writes go
2991          * in separate transaction */
2992         retval = dquot_initialize(dir);
2993         if (retval)
2994                 return retval;
2995         retval = dquot_initialize(d_inode(dentry));
2996         if (retval)
2997                 return retval;
2998 
2999         retval = -ENOENT;
3000         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3001         if (IS_ERR(bh))
3002                 return PTR_ERR(bh);
3003         if (!bh)
3004                 goto end_unlink;
3005 
3006         inode = d_inode(dentry);
3007 
3008         retval = -EFSCORRUPTED;
3009         if (le32_to_cpu(de->inode) != inode->i_ino)
3010                 goto end_unlink;
3011 
3012         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3013                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3014         if (IS_ERR(handle)) {
3015                 retval = PTR_ERR(handle);
3016                 handle = NULL;
3017                 goto end_unlink;
3018         }
3019 
3020         if (IS_DIRSYNC(dir))
3021                 ext4_handle_sync(handle);
3022 
3023         if (inode->i_nlink == 0) {
3024                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3025                                    dentry->d_name.len, dentry->d_name.name);
3026                 set_nlink(inode, 1);
3027         }
3028         retval = ext4_delete_entry(handle, dir, de, bh);
3029         if (retval)
3030                 goto end_unlink;
3031         dir->i_ctime = dir->i_mtime = current_time(dir);
3032         ext4_update_dx_flag(dir);
3033         ext4_mark_inode_dirty(handle, dir);
3034         drop_nlink(inode);
3035         if (!inode->i_nlink)
3036                 ext4_orphan_add(handle, inode);
3037         inode->i_ctime = current_time(inode);
3038         ext4_mark_inode_dirty(handle, inode);
3039 
3040 end_unlink:
3041         brelse(bh);
3042         if (handle)
3043                 ext4_journal_stop(handle);
3044         trace_ext4_unlink_exit(dentry, retval);
3045         return retval;
3046 }
3047 
3048 static int ext4_symlink(struct inode *dir,
3049                         struct dentry *dentry, const char *symname)
3050 {
3051         handle_t *handle;
3052         struct inode *inode;
3053         int err, len = strlen(symname);
3054         int credits;
3055         bool encryption_required;
3056         struct fscrypt_str disk_link;
3057         struct fscrypt_symlink_data *sd = NULL;
3058 
3059         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3060                 return -EIO;
3061 
3062         disk_link.len = len + 1;
3063         disk_link.name = (char *) symname;
3064 
3065         encryption_required = (ext4_encrypted_inode(dir) ||
3066                                DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
3067         if (encryption_required) {
3068                 err = fscrypt_get_encryption_info(dir);
3069                 if (err)
3070                         return err;
3071                 if (!fscrypt_has_encryption_key(dir))
3072                         return -ENOKEY;
3073                 disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
3074                                  sizeof(struct fscrypt_symlink_data));
3075                 sd = kzalloc(disk_link.len, GFP_KERNEL);
3076                 if (!sd)
3077                         return -ENOMEM;
3078         }
3079 
3080         if (disk_link.len > dir->i_sb->s_blocksize) {
3081                 err = -ENAMETOOLONG;
3082                 goto err_free_sd;
3083         }
3084 
3085         err = dquot_initialize(dir);
3086         if (err)
3087                 goto err_free_sd;
3088 
3089         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3090                 /*
3091                  * For non-fast symlinks, we just allocate inode and put it on
3092                  * orphan list in the first transaction => we need bitmap,
3093                  * group descriptor, sb, inode block, quota blocks, and
3094                  * possibly selinux xattr blocks.
3095                  */
3096                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3097                           EXT4_XATTR_TRANS_BLOCKS;
3098         } else {
3099                 /*
3100                  * Fast symlink. We have to add entry to directory
3101                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3102                  * allocate new inode (bitmap, group descriptor, inode block,
3103                  * quota blocks, sb is already counted in previous macros).
3104                  */
3105                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3106                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3107         }
3108 
3109         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3110                                             &dentry->d_name, 0, NULL,
3111                                             EXT4_HT_DIR, credits);
3112         handle = ext4_journal_current_handle();
3113         if (IS_ERR(inode)) {
3114                 if (handle)
3115                         ext4_journal_stop(handle);
3116                 err = PTR_ERR(inode);
3117                 goto err_free_sd;
3118         }
3119 
3120         if (encryption_required) {
3121                 struct qstr istr;
3122                 struct fscrypt_str ostr =
3123                         FSTR_INIT(sd->encrypted_path, disk_link.len);
3124 
3125                 istr.name = (const unsigned char *) symname;
3126                 istr.len = len;
3127                 err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
3128                 if (err)
3129                         goto err_drop_inode;
3130                 sd->len = cpu_to_le16(ostr.len);
3131                 disk_link.name = (char *) sd;
3132                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3133         }
3134 
3135         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3136                 if (!encryption_required)
3137                         inode->i_op = &ext4_symlink_inode_operations;
3138                 inode_nohighmem(inode);
3139                 ext4_set_aops(inode);
3140                 /*
3141                  * We cannot call page_symlink() with transaction started
3142                  * because it calls into ext4_write_begin() which can wait
3143                  * for transaction commit if we are running out of space
3144                  * and thus we deadlock. So we have to stop transaction now
3145                  * and restart it when symlink contents is written.
3146                  * 
3147                  * To keep fs consistent in case of crash, we have to put inode
3148                  * to orphan list in the mean time.
3149                  */
3150                 drop_nlink(inode);
3151                 err = ext4_orphan_add(handle, inode);
3152                 ext4_journal_stop(handle);
3153                 handle = NULL;
3154                 if (err)
3155                         goto err_drop_inode;
3156                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3157                 if (err)
3158                         goto err_drop_inode;
3159                 /*
3160                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3161                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3162                  */
3163                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3164                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3165                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3166                 if (IS_ERR(handle)) {
3167                         err = PTR_ERR(handle);
3168                         handle = NULL;
3169                         goto err_drop_inode;
3170                 }
3171                 set_nlink(inode, 1);
3172                 err = ext4_orphan_del(handle, inode);
3173                 if (err)
3174                         goto err_drop_inode;
3175         } else {
3176                 /* clear the extent format for fast symlink */
3177                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3178                 if (!encryption_required) {
3179                         inode->i_op = &ext4_fast_symlink_inode_operations;
3180                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3181                 }
3182                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3183                        disk_link.len);
3184                 inode->i_size = disk_link.len - 1;
3185         }
3186         EXT4_I(inode)->i_disksize = inode->i_size;
3187         err = ext4_add_nondir(handle, dentry, inode);
3188         if (!err && IS_DIRSYNC(dir))
3189                 ext4_handle_sync(handle);
3190 
3191         if (handle)
3192                 ext4_journal_stop(handle);
3193         kfree(sd);
3194         return err;
3195 err_drop_inode:
3196         if (handle)
3197                 ext4_journal_stop(handle);
3198         clear_nlink(inode);
3199         unlock_new_inode(inode);
3200         iput(inode);
3201 err_free_sd:
3202         kfree(sd);
3203         return err;
3204 }
3205 
3206 static int ext4_link(struct dentry *old_dentry,
3207                      struct inode *dir, struct dentry *dentry)
3208 {
3209         handle_t *handle;
3210         struct inode *inode = d_inode(old_dentry);
3211         int err, retries = 0;
3212 
3213         if (inode->i_nlink >= EXT4_LINK_MAX)
3214                 return -EMLINK;
3215 
3216         err = fscrypt_prepare_link(old_dentry, dir, dentry);
3217         if (err)
3218                 return err;
3219 
3220        if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3221            (!projid_eq(EXT4_I(dir)->i_projid,
3222                        EXT4_I(old_dentry->d_inode)->i_projid)))
3223                 return -EXDEV;
3224 
3225         err = dquot_initialize(dir);
3226         if (err)
3227                 return err;
3228 
3229 retry:
3230         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3231                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3232                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3233         if (IS_ERR(handle))
3234                 return PTR_ERR(handle);
3235 
3236         if (IS_DIRSYNC(dir))
3237                 ext4_handle_sync(handle);
3238 
3239         inode->i_ctime = current_time(inode);
3240         ext4_inc_count(handle, inode);
3241         ihold(inode);
3242 
3243         err = ext4_add_entry(handle, dentry, inode);
3244         if (!err) {
3245                 ext4_mark_inode_dirty(handle, inode);
3246                 /* this can happen only for tmpfile being
3247                  * linked the first time
3248                  */
3249                 if (inode->i_nlink == 1)
3250                         ext4_orphan_del(handle, inode);
3251                 d_instantiate(dentry, inode);
3252         } else {
3253                 drop_nlink(inode);
3254                 iput(inode);
3255         }
3256         ext4_journal_stop(handle);
3257         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3258                 goto retry;
3259         return err;
3260 }
3261 
3262 
3263 /*
3264  * Try to find buffer head where contains the parent block.
3265  * It should be the inode block if it is inlined or the 1st block
3266  * if it is a normal dir.
3267  */
3268 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3269                                         struct inode *inode,
3270                                         int *retval,
3271                                         struct ext4_dir_entry_2 **parent_de,
3272                                         int *inlined)
3273 {
3274         struct buffer_head *bh;
3275 
3276         if (!ext4_has_inline_data(inode)) {
3277                 bh = ext4_read_dirblock(inode, 0, EITHER);
3278                 if (IS_ERR(bh)) {
3279                         *retval = PTR_ERR(bh);
3280                         return NULL;
3281                 }
3282                 *parent_de = ext4_next_entry(
3283                                         (struct ext4_dir_entry_2 *)bh->b_data,
3284                                         inode->i_sb->s_blocksize);
3285                 return bh;
3286         }
3287 
3288         *inlined = 1;
3289         return ext4_get_first_inline_block(inode, parent_de, retval);
3290 }
3291 
3292 struct ext4_renament {
3293         struct inode *dir;
3294         struct dentry *dentry;
3295         struct inode *inode;
3296         bool is_dir;
3297         int dir_nlink_delta;
3298 
3299         /* entry for "dentry" */
3300         struct buffer_head *bh;
3301         struct ext4_dir_entry_2 *de;
3302         int inlined;
3303 
3304         /* entry for ".." in inode if it's a directory */
3305         struct buffer_head *dir_bh;
3306         struct ext4_dir_entry_2 *parent_de;
3307         int dir_inlined;
3308 };
3309 
3310 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3311 {
3312         int retval;
3313 
3314         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3315                                               &retval, &ent->parent_de,
3316                                               &ent->dir_inlined);
3317         if (!ent->dir_bh)
3318                 return retval;
3319         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3320                 return -EFSCORRUPTED;
3321         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3322         return ext4_journal_get_write_access(handle, ent->dir_bh);
3323 }
3324 
3325 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3326                                   unsigned dir_ino)
3327 {
3328         int retval;
3329 
3330         ent->parent_de->inode = cpu_to_le32(dir_ino);
3331         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3332         if (!ent->dir_inlined) {
3333                 if (is_dx(ent->inode)) {
3334                         retval = ext4_handle_dirty_dx_node(handle,
3335                                                            ent->inode,
3336                                                            ent->dir_bh);
3337                 } else {
3338                         retval = ext4_handle_dirty_dirent_node(handle,
3339                                                                ent->inode,
3340                                                                ent->dir_bh);
3341                 }
3342         } else {
3343                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3344         }
3345         if (retval) {
3346                 ext4_std_error(ent->dir->i_sb, retval);
3347                 return retval;
3348         }
3349         return 0;
3350 }
3351 
3352 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3353                        unsigned ino, unsigned file_type)
3354 {
3355         int retval;
3356 
3357         BUFFER_TRACE(ent->bh, "get write access");
3358         retval = ext4_journal_get_write_access(handle, ent->bh);
3359         if (retval)
3360                 return retval;
3361         ent->de->inode = cpu_to_le32(ino);
3362         if (ext4_has_feature_filetype(ent->dir->i_sb))
3363                 ent->de->file_type = file_type;
3364         ent->dir->i_version++;
3365         ent->dir->i_ctime = ent->dir->i_mtime =
3366                 current_time(ent->dir);
3367         ext4_mark_inode_dirty(handle, ent->dir);
3368         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3369         if (!ent->inlined) {
3370                 retval = ext4_handle_dirty_dirent_node(handle,
3371                                                        ent->dir, ent->bh);
3372                 if (unlikely(retval)) {
3373                         ext4_std_error(ent->dir->i_sb, retval);
3374                         return retval;
3375                 }
3376         }
3377         brelse(ent->bh);
3378         ent->bh = NULL;
3379 
3380         return 0;
3381 }
3382 
3383 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3384                                   const struct qstr *d_name)
3385 {
3386         int retval = -ENOENT;
3387         struct buffer_head *bh;
3388         struct ext4_dir_entry_2 *de;
3389 
3390         bh = ext4_find_entry(dir, d_name, &de, NULL);
3391         if (IS_ERR(bh))
3392                 return PTR_ERR(bh);
3393         if (bh) {
3394                 retval = ext4_delete_entry(handle, dir, de, bh);
3395                 brelse(bh);
3396         }
3397         return retval;
3398 }
3399 
3400 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3401                                int force_reread)
3402 {
3403         int retval;
3404         /*
3405          * ent->de could have moved from under us during htree split, so make
3406          * sure that we are deleting the right entry.  We might also be pointing
3407          * to a stale entry in the unused part of ent->bh so just checking inum
3408          * and the name isn't enough.
3409          */
3410         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3411             ent->de->name_len != ent->dentry->d_name.len ||
3412             strncmp(ent->de->name, ent->dentry->d_name.name,
3413                     ent->de->name_len) ||
3414             force_reread) {
3415                 retval = ext4_find_delete_entry(handle, ent->dir,
3416                                                 &ent->dentry->d_name);
3417         } else {
3418                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3419                 if (retval == -ENOENT) {
3420                         retval = ext4_find_delete_entry(handle, ent->dir,
3421                                                         &ent->dentry->d_name);
3422                 }
3423         }
3424 
3425         if (retval) {
3426                 ext4_warning_inode(ent->dir,
3427                                    "Deleting old file: nlink %d, error=%d",
3428                                    ent->dir->i_nlink, retval);
3429         }
3430 }
3431 
3432 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3433 {
3434         if (ent->dir_nlink_delta) {
3435                 if (ent->dir_nlink_delta == -1)
3436                         ext4_dec_count(handle, ent->dir);
3437                 else
3438                         ext4_inc_count(handle, ent->dir);
3439                 ext4_mark_inode_dirty(handle, ent->dir);
3440         }
3441 }
3442 
3443 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3444                                               int credits, handle_t **h)
3445 {
3446         struct inode *wh;
3447         handle_t *handle;
3448         int retries = 0;
3449 
3450         /*
3451          * for inode block, sb block, group summaries,
3452          * and inode bitmap
3453          */
3454         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3455                     EXT4_XATTR_TRANS_BLOCKS + 4);
3456 retry:
3457         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3458                                          &ent->dentry->d_name, 0, NULL,
3459                                          EXT4_HT_DIR, credits);
3460 
3461         handle = ext4_journal_current_handle();
3462         if (IS_ERR(wh)) {
3463                 if (handle)
3464                         ext4_journal_stop(handle);
3465                 if (PTR_ERR(wh) == -ENOSPC &&
3466                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3467                         goto retry;
3468         } else {
3469                 *h = handle;
3470                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3471                 wh->i_op = &ext4_special_inode_operations;
3472         }
3473         return wh;
3474 }
3475 
3476 /*
3477  * Anybody can rename anything with this: the permission checks are left to the
3478  * higher-level routines.
3479  *
3480  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3481  * while new_{dentry,inode) refers to the destination dentry/inode
3482  * This comes from rename(const char *oldpath, const char *newpath)
3483  */
3484 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3485                        struct inode *new_dir, struct dentry *new_dentry,
3486                        unsigned int flags)
3487 {
3488         handle_t *handle = NULL;
3489         struct ext4_renament old = {
3490                 .dir = old_dir,
3491                 .dentry = old_dentry,
3492                 .inode = d_inode(old_dentry),
3493         };
3494         struct ext4_renament new = {
3495                 .dir = new_dir,
3496                 .dentry = new_dentry,
3497                 .inode = d_inode(new_dentry),
3498         };
3499         int force_reread;
3500         int retval;
3501         struct inode *whiteout = NULL;
3502         int credits;
3503         u8 old_file_type;
3504 
3505         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3506             (!projid_eq(EXT4_I(new_dir)->i_projid,
3507                         EXT4_I(old_dentry->d_inode)->i_projid)))
3508                 return -EXDEV;
3509 
3510         retval = dquot_initialize(old.dir);
3511         if (retval)
3512                 return retval;
3513         retval = dquot_initialize(new.dir);
3514         if (retval)
3515                 return retval;
3516 
3517         /* Initialize quotas before so that eventual writes go
3518          * in separate transaction */
3519         if (new.inode) {
3520                 retval = dquot_initialize(new.inode);
3521                 if (retval)
3522                         return retval;
3523         }
3524 
3525         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3526         if (IS_ERR(old.bh))
3527                 return PTR_ERR(old.bh);
3528         /*
3529          *  Check for inode number is _not_ due to possible IO errors.
3530          *  We might rmdir the source, keep it as pwd of some process
3531          *  and merrily kill the link to whatever was created under the
3532          *  same name. Goodbye sticky bit ;-<
3533          */
3534         retval = -ENOENT;
3535         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3536                 goto end_rename;
3537 
3538         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3539                                  &new.de, &new.inlined);
3540         if (IS_ERR(new.bh)) {
3541                 retval = PTR_ERR(new.bh);
3542                 new.bh = NULL;
3543                 goto end_rename;
3544         }
3545         if (new.bh) {
3546                 if (!new.inode) {
3547                         brelse(new.bh);
3548                         new.bh = NULL;
3549                 }
3550         }
3551         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3552                 ext4_alloc_da_blocks(old.inode);
3553 
3554         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3555                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3556         if (!(flags & RENAME_WHITEOUT)) {
3557                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3558                 if (IS_ERR(handle)) {
3559                         retval = PTR_ERR(handle);
3560                         handle = NULL;
3561                         goto end_rename;
3562                 }
3563         } else {
3564                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3565                 if (IS_ERR(whiteout)) {
3566                         retval = PTR_ERR(whiteout);
3567                         whiteout = NULL;
3568                         goto end_rename;
3569                 }
3570         }
3571 
3572         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3573                 ext4_handle_sync(handle);
3574 
3575         if (S_ISDIR(old.inode->i_mode)) {
3576                 if (new.inode) {
3577                         retval = -ENOTEMPTY;
3578                         if (!ext4_empty_dir(new.inode))
3579                                 goto end_rename;
3580                 } else {
3581                         retval = -EMLINK;
3582                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3583                                 goto end_rename;
3584                 }
3585                 retval = ext4_rename_dir_prepare(handle, &old);
3586                 if (retval)
3587                         goto end_rename;
3588         }
3589         /*
3590          * If we're renaming a file within an inline_data dir and adding or
3591          * setting the new dirent causes a conversion from inline_data to
3592          * extents/blockmap, we need to force the dirent delete code to
3593          * re-read the directory, or else we end up trying to delete a dirent
3594          * from what is now the extent tree root (or a block map).
3595          */
3596         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3597                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3598 
3599         old_file_type = old.de->file_type;
3600         if (whiteout) {
3601                 /*
3602                  * Do this before adding a new entry, so the old entry is sure
3603                  * to be still pointing to the valid old entry.
3604                  */
3605                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3606                                      EXT4_FT_CHRDEV);
3607                 if (retval)
3608                         goto end_rename;
3609                 ext4_mark_inode_dirty(handle, whiteout);
3610         }
3611         if (!new.bh) {
3612                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3613                 if (retval)
3614                         goto end_rename;
3615         } else {
3616                 retval = ext4_setent(handle, &new,
3617                                      old.inode->i_ino, old_file_type);
3618                 if (retval)
3619                         goto end_rename;
3620         }
3621         if (force_reread)
3622                 force_reread = !ext4_test_inode_flag(new.dir,
3623                                                      EXT4_INODE_INLINE_DATA);
3624 
3625         /*
3626          * Like most other Unix systems, set the ctime for inodes on a
3627          * rename.
3628          */
3629         old.inode->i_ctime = current_time(old.inode);
3630         ext4_mark_inode_dirty(handle, old.inode);
3631 
3632         if (!whiteout) {
3633                 /*
3634                  * ok, that's it
3635                  */
3636                 ext4_rename_delete(handle, &old, force_reread);
3637         }
3638 
3639         if (new.inode) {
3640                 ext4_dec_count(handle, new.inode);
3641                 new.inode->i_ctime = current_time(new.inode);
3642         }
3643         old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
3644         ext4_update_dx_flag(old.dir);
3645         if (old.dir_bh) {
3646                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3647                 if (retval)
3648                         goto end_rename;
3649 
3650                 ext4_dec_count(handle, old.dir);
3651                 if (new.inode) {
3652                         /* checked ext4_empty_dir above, can't have another
3653                          * parent, ext4_dec_count() won't work for many-linked
3654                          * dirs */
3655                         clear_nlink(new.inode);
3656                 } else {
3657                         ext4_inc_count(handle, new.dir);
3658                         ext4_update_dx_flag(new.dir);
3659                         ext4_mark_inode_dirty(handle, new.dir);
3660                 }
3661         }
3662         ext4_mark_inode_dirty(handle, old.dir);
3663         if (new.inode) {
3664                 ext4_mark_inode_dirty(handle, new.inode);
3665                 if (!new.inode->i_nlink)
3666                         ext4_orphan_add(handle, new.inode);
3667         }
3668         retval = 0;
3669 
3670 end_rename:
3671         brelse(old.dir_bh);
3672         brelse(old.bh);
3673         brelse(new.bh);
3674         if (whiteout) {
3675                 if (retval)
3676                         drop_nlink(whiteout);
3677                 unlock_new_inode(whiteout);
3678                 iput(whiteout);
3679         }
3680         if (handle)
3681                 ext4_journal_stop(handle);
3682         return retval;
3683 }
3684 
3685 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3686                              struct inode *new_dir, struct dentry *new_dentry)
3687 {
3688         handle_t *handle = NULL;
3689         struct ext4_renament old = {
3690                 .dir = old_dir,
3691                 .dentry = old_dentry,
3692                 .inode = d_inode(old_dentry),
3693         };
3694         struct ext4_renament new = {
3695                 .dir = new_dir,
3696                 .dentry = new_dentry,
3697                 .inode = d_inode(new_dentry),
3698         };
3699         u8 new_file_type;
3700         int retval;
3701         struct timespec ctime;
3702 
3703         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
3704              !projid_eq(EXT4_I(new_dir)->i_projid,
3705                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
3706             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
3707              !projid_eq(EXT4_I(old_dir)->i_projid,
3708                         EXT4_I(new_dentry->d_inode)->i_projid)))
3709                 return -EXDEV;
3710 
3711         retval = dquot_initialize(old.dir);
3712         if (retval)
3713                 return retval;
3714         retval = dquot_initialize(new.dir);
3715         if (retval)
3716                 return retval;
3717 
3718         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3719                                  &old.de, &old.inlined);
3720         if (IS_ERR(old.bh))
3721                 return PTR_ERR(old.bh);
3722         /*
3723          *  Check for inode number is _not_ due to possible IO errors.
3724          *  We might rmdir the source, keep it as pwd of some process
3725          *  and merrily kill the link to whatever was created under the
3726          *  same name. Goodbye sticky bit ;-<
3727          */
3728         retval = -ENOENT;
3729         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3730                 goto end_rename;
3731 
3732         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3733                                  &new.de, &new.inlined);
3734         if (IS_ERR(new.bh)) {
3735                 retval = PTR_ERR(new.bh);
3736                 new.bh = NULL;
3737                 goto end_rename;
3738         }
3739 
3740         /* RENAME_EXCHANGE case: old *and* new must both exist */
3741         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3742                 goto end_rename;
3743 
3744         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3745                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3746                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3747         if (IS_ERR(handle)) {
3748                 retval = PTR_ERR(handle);
3749                 handle = NULL;
3750                 goto end_rename;
3751         }
3752 
3753         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3754                 ext4_handle_sync(handle);
3755 
3756         if (S_ISDIR(old.inode->i_mode)) {
3757                 old.is_dir = true;
3758                 retval = ext4_rename_dir_prepare(handle, &old);
3759                 if (retval)
3760                         goto end_rename;
3761         }
3762         if (S_ISDIR(new.inode->i_mode)) {
3763                 new.is_dir = true;
3764                 retval = ext4_rename_dir_prepare(handle, &new);
3765                 if (retval)
3766                         goto end_rename;
3767         }
3768 
3769         /*
3770          * Other than the special case of overwriting a directory, parents'
3771          * nlink only needs to be modified if this is a cross directory rename.
3772          */
3773         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3774                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3775                 new.dir_nlink_delta = -old.dir_nlink_delta;
3776                 retval = -EMLINK;
3777                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3778                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3779                         goto end_rename;
3780         }
3781 
3782         new_file_type = new.de->file_type;
3783         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3784         if (retval)
3785                 goto end_rename;
3786 
3787         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3788         if (retval)
3789                 goto end_rename;
3790 
3791         /*
3792          * Like most other Unix systems, set the ctime for inodes on a
3793          * rename.
3794          */
3795         ctime = current_time(old.inode);
3796         old.inode->i_ctime = ctime;
3797         new.inode->i_ctime = ctime;
3798         ext4_mark_inode_dirty(handle, old.inode);
3799         ext4_mark_inode_dirty(handle, new.inode);
3800 
3801         if (old.dir_bh) {
3802                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3803                 if (retval)
3804                         goto end_rename;
3805         }
3806         if (new.dir_bh) {
3807                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3808                 if (retval)
3809                         goto end_rename;
3810         }
3811         ext4_update_dir_count(handle, &old);
3812         ext4_update_dir_count(handle, &new);
3813         retval = 0;
3814 
3815 end_rename:
3816         brelse(old.dir_bh);
3817         brelse(new.dir_bh);
3818         brelse(old.bh);
3819         brelse(new.bh);
3820         if (handle)
3821                 ext4_journal_stop(handle);
3822         return retval;
3823 }
3824 
3825 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3826                         struct inode *new_dir, struct dentry *new_dentry,
3827                         unsigned int flags)
3828 {
3829         int err;
3830 
3831         if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
3832                 return -EIO;
3833 
3834         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3835                 return -EINVAL;
3836 
3837         err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
3838                                      flags);
3839         if (err)
3840                 return err;
3841 
3842         if (flags & RENAME_EXCHANGE) {
3843                 return ext4_cross_rename(old_dir, old_dentry,
3844                                          new_dir, new_dentry);
3845         }
3846 
3847         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3848 }
3849 
3850 /*
3851  * directories can handle most operations...
3852  */
3853 const struct inode_operations ext4_dir_inode_operations = {
3854         .create         = ext4_create,
3855         .lookup         = ext4_lookup,
3856         .link           = ext4_link,
3857         .unlink         = ext4_unlink,
3858         .symlink        = ext4_symlink,
3859         .mkdir          = ext4_mkdir,
3860         .rmdir          = ext4_rmdir,
3861         .mknod          = ext4_mknod,
3862         .tmpfile        = ext4_tmpfile,
3863         .rename         = ext4_rename2,
3864         .setattr        = ext4_setattr,
3865         .getattr        = ext4_getattr,
3866         .listxattr      = ext4_listxattr,
3867         .get_acl        = ext4_get_acl,
3868         .set_acl        = ext4_set_acl,
3869         .fiemap         = ext4_fiemap,
3870 };
3871 
3872 const struct inode_operations ext4_special_inode_operations = {
3873         .setattr        = ext4_setattr,
3874         .getattr        = ext4_getattr,
3875         .listxattr      = ext4_listxattr,
3876         .get_acl        = ext4_get_acl,
3877         .set_acl        = ext4_set_acl,
3878 };
3879 

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