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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 <linux/iversion.h>
 38 #include "ext4.h"
 39 #include "ext4_jbd2.h"
 40 
 41 #include "xattr.h"
 42 #include "acl.h"
 43 
 44 #include <trace/events/ext4.h>
 45 /*
 46  * define how far ahead to read directories while searching them.
 47  */
 48 #define NAMEI_RA_CHUNKS  2
 49 #define NAMEI_RA_BLOCKS  4
 50 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
 51 
 52 static struct buffer_head *ext4_append(handle_t *handle,
 53                                         struct inode *inode,
 54                                         ext4_lblk_t *block)
 55 {
 56         struct buffer_head *bh;
 57         int err;
 58 
 59         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
 60                      ((inode->i_size >> 10) >=
 61                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
 62                 return ERR_PTR(-ENOSPC);
 63 
 64         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
 65 
 66         bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
 67         if (IS_ERR(bh))
 68                 return bh;
 69         inode->i_size += inode->i_sb->s_blocksize;
 70         EXT4_I(inode)->i_disksize = inode->i_size;
 71         BUFFER_TRACE(bh, "get_write_access");
 72         err = ext4_journal_get_write_access(handle, bh);
 73         if (err) {
 74                 brelse(bh);
 75                 ext4_std_error(inode->i_sb, err);
 76                 return ERR_PTR(err);
 77         }
 78         return bh;
 79 }
 80 
 81 static int ext4_dx_csum_verify(struct inode *inode,
 82                                struct ext4_dir_entry *dirent);
 83 
 84 typedef enum {
 85         EITHER, INDEX, DIRENT
 86 } dirblock_type_t;
 87 
 88 #define ext4_read_dirblock(inode, block, type) \
 89         __ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
 90 
 91 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
 92                                                 ext4_lblk_t block,
 93                                                 dirblock_type_t type,
 94                                                 const char *func,
 95                                                 unsigned int line)
 96 {
 97         struct buffer_head *bh;
 98         struct ext4_dir_entry *dirent;
 99         int is_dx_block = 0;
100 
101         bh = ext4_bread(NULL, inode, block, 0);
102         if (IS_ERR(bh)) {
103                 __ext4_warning(inode->i_sb, func, line,
104                                "inode #%lu: lblock %lu: comm %s: "
105                                "error %ld reading directory block",
106                                inode->i_ino, (unsigned long)block,
107                                current->comm, PTR_ERR(bh));
108 
109                 return bh;
110         }
111         if (!bh) {
112                 ext4_error_inode(inode, func, line, block,
113                                  "Directory hole found");
114                 return ERR_PTR(-EFSCORRUPTED);
115         }
116         dirent = (struct ext4_dir_entry *) bh->b_data;
117         /* Determine whether or not we have an index block */
118         if (is_dx(inode)) {
119                 if (block == 0)
120                         is_dx_block = 1;
121                 else if (ext4_rec_len_from_disk(dirent->rec_len,
122                                                 inode->i_sb->s_blocksize) ==
123                          inode->i_sb->s_blocksize)
124                         is_dx_block = 1;
125         }
126         if (!is_dx_block && type == INDEX) {
127                 ext4_error_inode(inode, func, line, block,
128                        "directory leaf block found instead of index block");
129                 brelse(bh);
130                 return ERR_PTR(-EFSCORRUPTED);
131         }
132         if (!ext4_has_metadata_csum(inode->i_sb) ||
133             buffer_verified(bh))
134                 return bh;
135 
136         /*
137          * An empty leaf block can get mistaken for a index block; for
138          * this reason, we can only check the index checksum when the
139          * caller is sure it should be an index block.
140          */
141         if (is_dx_block && type == INDEX) {
142                 if (ext4_dx_csum_verify(inode, dirent))
143                         set_buffer_verified(bh);
144                 else {
145                         ext4_error_inode(inode, func, line, block,
146                                          "Directory index failed checksum");
147                         brelse(bh);
148                         return ERR_PTR(-EFSBADCRC);
149                 }
150         }
151         if (!is_dx_block) {
152                 if (ext4_dirent_csum_verify(inode, dirent))
153                         set_buffer_verified(bh);
154                 else {
155                         ext4_error_inode(inode, func, line, block,
156                                          "Directory block failed checksum");
157                         brelse(bh);
158                         return ERR_PTR(-EFSBADCRC);
159                 }
160         }
161         return bh;
162 }
163 
164 #ifndef assert
165 #define assert(test) J_ASSERT(test)
166 #endif
167 
168 #ifdef DX_DEBUG
169 #define dxtrace(command) command
170 #else
171 #define dxtrace(command)
172 #endif
173 
174 struct fake_dirent
175 {
176         __le32 inode;
177         __le16 rec_len;
178         u8 name_len;
179         u8 file_type;
180 };
181 
182 struct dx_countlimit
183 {
184         __le16 limit;
185         __le16 count;
186 };
187 
188 struct dx_entry
189 {
190         __le32 hash;
191         __le32 block;
192 };
193 
194 /*
195  * dx_root_info is laid out so that if it should somehow get overlaid by a
196  * dirent the two low bits of the hash version will be zero.  Therefore, the
197  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
198  */
199 
200 struct dx_root
201 {
202         struct fake_dirent dot;
203         char dot_name[4];
204         struct fake_dirent dotdot;
205         char dotdot_name[4];
206         struct dx_root_info
207         {
208                 __le32 reserved_zero;
209                 u8 hash_version;
210                 u8 info_length; /* 8 */
211                 u8 indirect_levels;
212                 u8 unused_flags;
213         }
214         info;
215         struct dx_entry entries[0];
216 };
217 
218 struct dx_node
219 {
220         struct fake_dirent fake;
221         struct dx_entry entries[0];
222 };
223 
224 
225 struct dx_frame
226 {
227         struct buffer_head *bh;
228         struct dx_entry *entries;
229         struct dx_entry *at;
230 };
231 
232 struct dx_map_entry
233 {
234         u32 hash;
235         u16 offs;
236         u16 size;
237 };
238 
239 /*
240  * This goes at the end of each htree block.
241  */
242 struct dx_tail {
243         u32 dt_reserved;
244         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
245 };
246 
247 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
248 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
249 static inline unsigned dx_get_hash(struct dx_entry *entry);
250 static void dx_set_hash(struct dx_entry *entry, unsigned value);
251 static unsigned dx_get_count(struct dx_entry *entries);
252 static unsigned dx_get_limit(struct dx_entry *entries);
253 static void dx_set_count(struct dx_entry *entries, unsigned value);
254 static void dx_set_limit(struct dx_entry *entries, unsigned value);
255 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
256 static unsigned dx_node_limit(struct inode *dir);
257 static struct dx_frame *dx_probe(struct ext4_filename *fname,
258                                  struct inode *dir,
259                                  struct dx_hash_info *hinfo,
260                                  struct dx_frame *frame);
261 static void dx_release(struct dx_frame *frames);
262 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
263                        unsigned blocksize, struct dx_hash_info *hinfo,
264                        struct dx_map_entry map[]);
265 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
266 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
267                 struct dx_map_entry *offsets, int count, unsigned blocksize);
268 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
269 static void dx_insert_block(struct dx_frame *frame,
270                                         u32 hash, ext4_lblk_t block);
271 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
272                                  struct dx_frame *frame,
273                                  struct dx_frame *frames,
274                                  __u32 *start_hash);
275 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
276                 struct ext4_filename *fname,
277                 struct ext4_dir_entry_2 **res_dir);
278 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
279                              struct inode *dir, struct inode *inode);
280 
281 /* checksumming functions */
282 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
283                             unsigned int blocksize)
284 {
285         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
286         t->det_rec_len = ext4_rec_len_to_disk(
287                         sizeof(struct ext4_dir_entry_tail), blocksize);
288         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
289 }
290 
291 /* Walk through a dirent block to find a checksum "dirent" at the tail */
292 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
293                                                    struct ext4_dir_entry *de)
294 {
295         struct ext4_dir_entry_tail *t;
296 
297 #ifdef PARANOID
298         struct ext4_dir_entry *d, *top;
299 
300         d = de;
301         top = (struct ext4_dir_entry *)(((void *)de) +
302                 (EXT4_BLOCK_SIZE(inode->i_sb) -
303                 sizeof(struct ext4_dir_entry_tail)));
304         while (d < top && d->rec_len)
305                 d = (struct ext4_dir_entry *)(((void *)d) +
306                     le16_to_cpu(d->rec_len));
307 
308         if (d != top)
309                 return NULL;
310 
311         t = (struct ext4_dir_entry_tail *)d;
312 #else
313         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
314 #endif
315 
316         if (t->det_reserved_zero1 ||
317             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
318             t->det_reserved_zero2 ||
319             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
320                 return NULL;
321 
322         return t;
323 }
324 
325 static __le32 ext4_dirent_csum(struct inode *inode,
326                                struct ext4_dir_entry *dirent, int size)
327 {
328         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
329         struct ext4_inode_info *ei = EXT4_I(inode);
330         __u32 csum;
331 
332         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
333         return cpu_to_le32(csum);
334 }
335 
336 #define warn_no_space_for_csum(inode)                                   \
337         __warn_no_space_for_csum((inode), __func__, __LINE__)
338 
339 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
340                                      unsigned int line)
341 {
342         __ext4_warning_inode(inode, func, line,
343                 "No space for directory leaf checksum. Please run e2fsck -D.");
344 }
345 
346 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
347 {
348         struct ext4_dir_entry_tail *t;
349 
350         if (!ext4_has_metadata_csum(inode->i_sb))
351                 return 1;
352 
353         t = get_dirent_tail(inode, dirent);
354         if (!t) {
355                 warn_no_space_for_csum(inode);
356                 return 0;
357         }
358 
359         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
360                                                 (void *)t - (void *)dirent))
361                 return 0;
362 
363         return 1;
364 }
365 
366 static void ext4_dirent_csum_set(struct inode *inode,
367                                  struct ext4_dir_entry *dirent)
368 {
369         struct ext4_dir_entry_tail *t;
370 
371         if (!ext4_has_metadata_csum(inode->i_sb))
372                 return;
373 
374         t = get_dirent_tail(inode, dirent);
375         if (!t) {
376                 warn_no_space_for_csum(inode);
377                 return;
378         }
379 
380         t->det_checksum = ext4_dirent_csum(inode, dirent,
381                                            (void *)t - (void *)dirent);
382 }
383 
384 int ext4_handle_dirty_dirent_node(handle_t *handle,
385                                   struct inode *inode,
386                                   struct buffer_head *bh)
387 {
388         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
389         return ext4_handle_dirty_metadata(handle, inode, bh);
390 }
391 
392 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
393                                                struct ext4_dir_entry *dirent,
394                                                int *offset)
395 {
396         struct ext4_dir_entry *dp;
397         struct dx_root_info *root;
398         int count_offset;
399 
400         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
401                 count_offset = 8;
402         else if (le16_to_cpu(dirent->rec_len) == 12) {
403                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
404                 if (le16_to_cpu(dp->rec_len) !=
405                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
406                         return NULL;
407                 root = (struct dx_root_info *)(((void *)dp + 12));
408                 if (root->reserved_zero ||
409                     root->info_length != sizeof(struct dx_root_info))
410                         return NULL;
411                 count_offset = 32;
412         } else
413                 return NULL;
414 
415         if (offset)
416                 *offset = count_offset;
417         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
418 }
419 
420 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
421                            int count_offset, int count, struct dx_tail *t)
422 {
423         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
424         struct ext4_inode_info *ei = EXT4_I(inode);
425         __u32 csum;
426         int size;
427         __u32 dummy_csum = 0;
428         int offset = offsetof(struct dx_tail, dt_checksum);
429 
430         size = count_offset + (count * sizeof(struct dx_entry));
431         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
432         csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
433         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
434 
435         return cpu_to_le32(csum);
436 }
437 
438 static int ext4_dx_csum_verify(struct inode *inode,
439                                struct ext4_dir_entry *dirent)
440 {
441         struct dx_countlimit *c;
442         struct dx_tail *t;
443         int count_offset, limit, count;
444 
445         if (!ext4_has_metadata_csum(inode->i_sb))
446                 return 1;
447 
448         c = get_dx_countlimit(inode, dirent, &count_offset);
449         if (!c) {
450                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
451                 return 0;
452         }
453         limit = le16_to_cpu(c->limit);
454         count = le16_to_cpu(c->count);
455         if (count_offset + (limit * sizeof(struct dx_entry)) >
456             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
457                 warn_no_space_for_csum(inode);
458                 return 0;
459         }
460         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
461 
462         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
463                                             count, t))
464                 return 0;
465         return 1;
466 }
467 
468 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
469 {
470         struct dx_countlimit *c;
471         struct dx_tail *t;
472         int count_offset, limit, count;
473 
474         if (!ext4_has_metadata_csum(inode->i_sb))
475                 return;
476 
477         c = get_dx_countlimit(inode, dirent, &count_offset);
478         if (!c) {
479                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
480                 return;
481         }
482         limit = le16_to_cpu(c->limit);
483         count = le16_to_cpu(c->count);
484         if (count_offset + (limit * sizeof(struct dx_entry)) >
485             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
486                 warn_no_space_for_csum(inode);
487                 return;
488         }
489         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
490 
491         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
492 }
493 
494 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
495                                             struct inode *inode,
496                                             struct buffer_head *bh)
497 {
498         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
499         return ext4_handle_dirty_metadata(handle, inode, bh);
500 }
501 
502 /*
503  * p is at least 6 bytes before the end of page
504  */
505 static inline struct ext4_dir_entry_2 *
506 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
507 {
508         return (struct ext4_dir_entry_2 *)((char *)p +
509                 ext4_rec_len_from_disk(p->rec_len, blocksize));
510 }
511 
512 /*
513  * Future: use high four bits of block for coalesce-on-delete flags
514  * Mask them off for now.
515  */
516 
517 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
518 {
519         return le32_to_cpu(entry->block) & 0x0fffffff;
520 }
521 
522 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
523 {
524         entry->block = cpu_to_le32(value);
525 }
526 
527 static inline unsigned dx_get_hash(struct dx_entry *entry)
528 {
529         return le32_to_cpu(entry->hash);
530 }
531 
532 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
533 {
534         entry->hash = cpu_to_le32(value);
535 }
536 
537 static inline unsigned dx_get_count(struct dx_entry *entries)
538 {
539         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
540 }
541 
542 static inline unsigned dx_get_limit(struct dx_entry *entries)
543 {
544         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
545 }
546 
547 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
548 {
549         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
550 }
551 
552 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
553 {
554         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
555 }
556 
557 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
558 {
559         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
560                 EXT4_DIR_REC_LEN(2) - infosize;
561 
562         if (ext4_has_metadata_csum(dir->i_sb))
563                 entry_space -= sizeof(struct dx_tail);
564         return entry_space / sizeof(struct dx_entry);
565 }
566 
567 static inline unsigned dx_node_limit(struct inode *dir)
568 {
569         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
570 
571         if (ext4_has_metadata_csum(dir->i_sb))
572                 entry_space -= sizeof(struct dx_tail);
573         return entry_space / sizeof(struct dx_entry);
574 }
575 
576 /*
577  * Debug
578  */
579 #ifdef DX_DEBUG
580 static void dx_show_index(char * label, struct dx_entry *entries)
581 {
582         int i, n = dx_get_count (entries);
583         printk(KERN_DEBUG "%s index", label);
584         for (i = 0; i < n; i++) {
585                 printk(KERN_CONT " %x->%lu",
586                        i ? dx_get_hash(entries + i) : 0,
587                        (unsigned long)dx_get_block(entries + i));
588         }
589         printk(KERN_CONT "\n");
590 }
591 
592 struct stats
593 {
594         unsigned names;
595         unsigned space;
596         unsigned bcount;
597 };
598 
599 static struct stats dx_show_leaf(struct inode *dir,
600                                 struct dx_hash_info *hinfo,
601                                 struct ext4_dir_entry_2 *de,
602                                 int size, int show_names)
603 {
604         unsigned names = 0, space = 0;
605         char *base = (char *) de;
606         struct dx_hash_info h = *hinfo;
607 
608         printk("names: ");
609         while ((char *) de < base + size)
610         {
611                 if (de->inode)
612                 {
613                         if (show_names)
614                         {
615 #ifdef CONFIG_EXT4_FS_ENCRYPTION
616                                 int len;
617                                 char *name;
618                                 struct fscrypt_str fname_crypto_str =
619                                         FSTR_INIT(NULL, 0);
620                                 int res = 0;
621 
622                                 name  = de->name;
623                                 len = de->name_len;
624                                 if (ext4_encrypted_inode(dir))
625                                         res = fscrypt_get_encryption_info(dir);
626                                 if (res) {
627                                         printk(KERN_WARNING "Error setting up"
628                                                " fname crypto: %d\n", res);
629                                 }
630                                 if (!fscrypt_has_encryption_key(dir)) {
631                                         /* Directory is not encrypted */
632                                         ext4fs_dirhash(de->name,
633                                                 de->name_len, &h);
634                                         printk("%*.s:(U)%x.%u ", len,
635                                                name, h.hash,
636                                                (unsigned) ((char *) de
637                                                            - base));
638                                 } else {
639                                         struct fscrypt_str de_name =
640                                                 FSTR_INIT(name, len);
641 
642                                         /* Directory is encrypted */
643                                         res = fscrypt_fname_alloc_buffer(
644                                                 dir, len,
645                                                 &fname_crypto_str);
646                                         if (res)
647                                                 printk(KERN_WARNING "Error "
648                                                         "allocating crypto "
649                                                         "buffer--skipping "
650                                                         "crypto\n");
651                                         res = fscrypt_fname_disk_to_usr(dir,
652                                                 0, 0, &de_name,
653                                                 &fname_crypto_str);
654                                         if (res) {
655                                                 printk(KERN_WARNING "Error "
656                                                         "converting filename "
657                                                         "from disk to usr"
658                                                         "\n");
659                                                 name = "??";
660                                                 len = 2;
661                                         } else {
662                                                 name = fname_crypto_str.name;
663                                                 len = fname_crypto_str.len;
664                                         }
665                                         ext4fs_dirhash(de->name, de->name_len,
666                                                        &h);
667                                         printk("%*.s:(E)%x.%u ", len, name,
668                                                h.hash, (unsigned) ((char *) de
669                                                                    - base));
670                                         fscrypt_fname_free_buffer(
671                                                         &fname_crypto_str);
672                                 }
673 #else
674                                 int len = de->name_len;
675                                 char *name = de->name;
676                                 ext4fs_dirhash(de->name, de->name_len, &h);
677                                 printk("%*.s:%x.%u ", len, name, h.hash,
678                                        (unsigned) ((char *) de - base));
679 #endif
680                         }
681                         space += EXT4_DIR_REC_LEN(de->name_len);
682                         names++;
683                 }
684                 de = ext4_next_entry(de, size);
685         }
686         printk(KERN_CONT "(%i)\n", names);
687         return (struct stats) { names, space, 1 };
688 }
689 
690 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
691                              struct dx_entry *entries, int levels)
692 {
693         unsigned blocksize = dir->i_sb->s_blocksize;
694         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
695         unsigned bcount = 0;
696         struct buffer_head *bh;
697         printk("%i indexed blocks...\n", count);
698         for (i = 0; i < count; i++, entries++)
699         {
700                 ext4_lblk_t block = dx_get_block(entries);
701                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
702                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
703                 struct stats stats;
704                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
705                 bh = ext4_bread(NULL,dir, block, 0);
706                 if (!bh || IS_ERR(bh))
707                         continue;
708                 stats = levels?
709                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
710                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
711                         bh->b_data, blocksize, 0);
712                 names += stats.names;
713                 space += stats.space;
714                 bcount += stats.bcount;
715                 brelse(bh);
716         }
717         if (bcount)
718                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
719                        levels ? "" : "   ", names, space/bcount,
720                        (space/bcount)*100/blocksize);
721         return (struct stats) { names, space, bcount};
722 }
723 #endif /* DX_DEBUG */
724 
725 /*
726  * Probe for a directory leaf block to search.
727  *
728  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
729  * error in the directory index, and the caller should fall back to
730  * searching the directory normally.  The callers of dx_probe **MUST**
731  * check for this error code, and make sure it never gets reflected
732  * back to userspace.
733  */
734 static struct dx_frame *
735 dx_probe(struct ext4_filename *fname, struct inode *dir,
736          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
737 {
738         unsigned count, indirect;
739         struct dx_entry *at, *entries, *p, *q, *m;
740         struct dx_root *root;
741         struct dx_frame *frame = frame_in;
742         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
743         u32 hash;
744 
745         memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
746         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
747         if (IS_ERR(frame->bh))
748                 return (struct dx_frame *) frame->bh;
749 
750         root = (struct dx_root *) frame->bh->b_data;
751         if (root->info.hash_version != DX_HASH_TEA &&
752             root->info.hash_version != DX_HASH_HALF_MD4 &&
753             root->info.hash_version != DX_HASH_LEGACY) {
754                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
755                                    root->info.hash_version);
756                 goto fail;
757         }
758         if (fname)
759                 hinfo = &fname->hinfo;
760         hinfo->hash_version = root->info.hash_version;
761         if (hinfo->hash_version <= DX_HASH_TEA)
762                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
763         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
764         if (fname && fname_name(fname))
765                 ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
766         hash = hinfo->hash;
767 
768         if (root->info.unused_flags & 1) {
769                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
770                                    root->info.unused_flags);
771                 goto fail;
772         }
773 
774         indirect = root->info.indirect_levels;
775         if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
776                 ext4_warning(dir->i_sb,
777                              "Directory (ino: %lu) htree depth %#06x exceed"
778                              "supported value", dir->i_ino,
779                              ext4_dir_htree_level(dir->i_sb));
780                 if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
781                         ext4_warning(dir->i_sb, "Enable large directory "
782                                                 "feature to access it");
783                 }
784                 goto fail;
785         }
786 
787         entries = (struct dx_entry *)(((char *)&root->info) +
788                                       root->info.info_length);
789 
790         if (dx_get_limit(entries) != dx_root_limit(dir,
791                                                    root->info.info_length)) {
792                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
793                                    dx_get_limit(entries),
794                                    dx_root_limit(dir, root->info.info_length));
795                 goto fail;
796         }
797 
798         dxtrace(printk("Look up %x", hash));
799         while (1) {
800                 count = dx_get_count(entries);
801                 if (!count || count > dx_get_limit(entries)) {
802                         ext4_warning_inode(dir,
803                                            "dx entry: count %u beyond limit %u",
804                                            count, dx_get_limit(entries));
805                         goto fail;
806                 }
807 
808                 p = entries + 1;
809                 q = entries + count - 1;
810                 while (p <= q) {
811                         m = p + (q - p) / 2;
812                         dxtrace(printk(KERN_CONT "."));
813                         if (dx_get_hash(m) > hash)
814                                 q = m - 1;
815                         else
816                                 p = m + 1;
817                 }
818 
819                 if (0) { // linear search cross check
820                         unsigned n = count - 1;
821                         at = entries;
822                         while (n--)
823                         {
824                                 dxtrace(printk(KERN_CONT ","));
825                                 if (dx_get_hash(++at) > hash)
826                                 {
827                                         at--;
828                                         break;
829                                 }
830                         }
831                         assert (at == p - 1);
832                 }
833 
834                 at = p - 1;
835                 dxtrace(printk(KERN_CONT " %x->%u\n",
836                                at == entries ? 0 : dx_get_hash(at),
837                                dx_get_block(at)));
838                 frame->entries = entries;
839                 frame->at = at;
840                 if (!indirect--)
841                         return frame;
842                 frame++;
843                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
844                 if (IS_ERR(frame->bh)) {
845                         ret_err = (struct dx_frame *) frame->bh;
846                         frame->bh = NULL;
847                         goto fail;
848                 }
849                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
850 
851                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
852                         ext4_warning_inode(dir,
853                                 "dx entry: limit %u != node limit %u",
854                                 dx_get_limit(entries), dx_node_limit(dir));
855                         goto fail;
856                 }
857         }
858 fail:
859         while (frame >= frame_in) {
860                 brelse(frame->bh);
861                 frame--;
862         }
863 
864         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
865                 ext4_warning_inode(dir,
866                         "Corrupt directory, running e2fsck is recommended");
867         return ret_err;
868 }
869 
870 static void dx_release(struct dx_frame *frames)
871 {
872         struct dx_root_info *info;
873         int i;
874 
875         if (frames[0].bh == NULL)
876                 return;
877 
878         info = &((struct dx_root *)frames[0].bh->b_data)->info;
879         for (i = 0; i <= info->indirect_levels; i++) {
880                 if (frames[i].bh == NULL)
881                         break;
882                 brelse(frames[i].bh);
883                 frames[i].bh = NULL;
884         }
885 }
886 
887 /*
888  * This function increments the frame pointer to search the next leaf
889  * block, and reads in the necessary intervening nodes if the search
890  * should be necessary.  Whether or not the search is necessary is
891  * controlled by the hash parameter.  If the hash value is even, then
892  * the search is only continued if the next block starts with that
893  * hash value.  This is used if we are searching for a specific file.
894  *
895  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
896  *
897  * This function returns 1 if the caller should continue to search,
898  * or 0 if it should not.  If there is an error reading one of the
899  * index blocks, it will a negative error code.
900  *
901  * If start_hash is non-null, it will be filled in with the starting
902  * hash of the next page.
903  */
904 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
905                                  struct dx_frame *frame,
906                                  struct dx_frame *frames,
907                                  __u32 *start_hash)
908 {
909         struct dx_frame *p;
910         struct buffer_head *bh;
911         int num_frames = 0;
912         __u32 bhash;
913 
914         p = frame;
915         /*
916          * Find the next leaf page by incrementing the frame pointer.
917          * If we run out of entries in the interior node, loop around and
918          * increment pointer in the parent node.  When we break out of
919          * this loop, num_frames indicates the number of interior
920          * nodes need to be read.
921          */
922         while (1) {
923                 if (++(p->at) < p->entries + dx_get_count(p->entries))
924                         break;
925                 if (p == frames)
926                         return 0;
927                 num_frames++;
928                 p--;
929         }
930 
931         /*
932          * If the hash is 1, then continue only if the next page has a
933          * continuation hash of any value.  This is used for readdir
934          * handling.  Otherwise, check to see if the hash matches the
935          * desired contiuation hash.  If it doesn't, return since
936          * there's no point to read in the successive index pages.
937          */
938         bhash = dx_get_hash(p->at);
939         if (start_hash)
940                 *start_hash = bhash;
941         if ((hash & 1) == 0) {
942                 if ((bhash & ~1) != hash)
943                         return 0;
944         }
945         /*
946          * If the hash is HASH_NB_ALWAYS, we always go to the next
947          * block so no check is necessary
948          */
949         while (num_frames--) {
950                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
951                 if (IS_ERR(bh))
952                         return PTR_ERR(bh);
953                 p++;
954                 brelse(p->bh);
955                 p->bh = bh;
956                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
957         }
958         return 1;
959 }
960 
961 
962 /*
963  * This function fills a red-black tree with information from a
964  * directory block.  It returns the number directory entries loaded
965  * into the tree.  If there is an error it is returned in err.
966  */
967 static int htree_dirblock_to_tree(struct file *dir_file,
968                                   struct inode *dir, ext4_lblk_t block,
969                                   struct dx_hash_info *hinfo,
970                                   __u32 start_hash, __u32 start_minor_hash)
971 {
972         struct buffer_head *bh;
973         struct ext4_dir_entry_2 *de, *top;
974         int err = 0, count = 0;
975         struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
976 
977         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
978                                                         (unsigned long)block));
979         bh = ext4_read_dirblock(dir, block, DIRENT);
980         if (IS_ERR(bh))
981                 return PTR_ERR(bh);
982 
983         de = (struct ext4_dir_entry_2 *) bh->b_data;
984         top = (struct ext4_dir_entry_2 *) ((char *) de +
985                                            dir->i_sb->s_blocksize -
986                                            EXT4_DIR_REC_LEN(0));
987 #ifdef CONFIG_EXT4_FS_ENCRYPTION
988         /* Check if the directory is encrypted */
989         if (ext4_encrypted_inode(dir)) {
990                 err = fscrypt_get_encryption_info(dir);
991                 if (err < 0) {
992                         brelse(bh);
993                         return err;
994                 }
995                 err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
996                                                      &fname_crypto_str);
997                 if (err < 0) {
998                         brelse(bh);
999                         return err;
1000                 }
1001         }
1002 #endif
1003         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
1004                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1005                                 bh->b_data, bh->b_size,
1006                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
1007                                          + ((char *)de - bh->b_data))) {
1008                         /* silently ignore the rest of the block */
1009                         break;
1010                 }
1011                 ext4fs_dirhash(de->name, de->name_len, hinfo);
1012                 if ((hinfo->hash < start_hash) ||
1013                     ((hinfo->hash == start_hash) &&
1014                      (hinfo->minor_hash < start_minor_hash)))
1015                         continue;
1016                 if (de->inode == 0)
1017                         continue;
1018                 if (!ext4_encrypted_inode(dir)) {
1019                         tmp_str.name = de->name;
1020                         tmp_str.len = de->name_len;
1021                         err = ext4_htree_store_dirent(dir_file,
1022                                    hinfo->hash, hinfo->minor_hash, de,
1023                                    &tmp_str);
1024                 } else {
1025                         int save_len = fname_crypto_str.len;
1026                         struct fscrypt_str de_name = FSTR_INIT(de->name,
1027                                                                 de->name_len);
1028 
1029                         /* Directory is encrypted */
1030                         err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1031                                         hinfo->minor_hash, &de_name,
1032                                         &fname_crypto_str);
1033                         if (err) {
1034                                 count = err;
1035                                 goto errout;
1036                         }
1037                         err = ext4_htree_store_dirent(dir_file,
1038                                    hinfo->hash, hinfo->minor_hash, de,
1039                                         &fname_crypto_str);
1040                         fname_crypto_str.len = save_len;
1041                 }
1042                 if (err != 0) {
1043                         count = err;
1044                         goto errout;
1045                 }
1046                 count++;
1047         }
1048 errout:
1049         brelse(bh);
1050 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1051         fscrypt_fname_free_buffer(&fname_crypto_str);
1052 #endif
1053         return count;
1054 }
1055 
1056 
1057 /*
1058  * This function fills a red-black tree with information from a
1059  * directory.  We start scanning the directory in hash order, starting
1060  * at start_hash and start_minor_hash.
1061  *
1062  * This function returns the number of entries inserted into the tree,
1063  * or a negative error code.
1064  */
1065 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1066                          __u32 start_minor_hash, __u32 *next_hash)
1067 {
1068         struct dx_hash_info hinfo;
1069         struct ext4_dir_entry_2 *de;
1070         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1071         struct inode *dir;
1072         ext4_lblk_t block;
1073         int count = 0;
1074         int ret, err;
1075         __u32 hashval;
1076         struct fscrypt_str tmp_str;
1077 
1078         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1079                        start_hash, start_minor_hash));
1080         dir = file_inode(dir_file);
1081         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1082                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1083                 if (hinfo.hash_version <= DX_HASH_TEA)
1084                         hinfo.hash_version +=
1085                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1086                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1087                 if (ext4_has_inline_data(dir)) {
1088                         int has_inline_data = 1;
1089                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
1090                                                         &hinfo, start_hash,
1091                                                         start_minor_hash,
1092                                                         &has_inline_data);
1093                         if (has_inline_data) {
1094                                 *next_hash = ~0;
1095                                 return count;
1096                         }
1097                 }
1098                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1099                                                start_hash, start_minor_hash);
1100                 *next_hash = ~0;
1101                 return count;
1102         }
1103         hinfo.hash = start_hash;
1104         hinfo.minor_hash = 0;
1105         frame = dx_probe(NULL, dir, &hinfo, frames);
1106         if (IS_ERR(frame))
1107                 return PTR_ERR(frame);
1108 
1109         /* Add '.' and '..' from the htree header */
1110         if (!start_hash && !start_minor_hash) {
1111                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1112                 tmp_str.name = de->name;
1113                 tmp_str.len = de->name_len;
1114                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1115                                               de, &tmp_str);
1116                 if (err != 0)
1117                         goto errout;
1118                 count++;
1119         }
1120         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1121                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1122                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1123                 tmp_str.name = de->name;
1124                 tmp_str.len = de->name_len;
1125                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1126                                               de, &tmp_str);
1127                 if (err != 0)
1128                         goto errout;
1129                 count++;
1130         }
1131 
1132         while (1) {
1133                 if (fatal_signal_pending(current)) {
1134                         err = -ERESTARTSYS;
1135                         goto errout;
1136                 }
1137                 cond_resched();
1138                 block = dx_get_block(frame->at);
1139                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1140                                              start_hash, start_minor_hash);
1141                 if (ret < 0) {
1142                         err = ret;
1143                         goto errout;
1144                 }
1145                 count += ret;
1146                 hashval = ~0;
1147                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1148                                             frame, frames, &hashval);
1149                 *next_hash = hashval;
1150                 if (ret < 0) {
1151                         err = ret;
1152                         goto errout;
1153                 }
1154                 /*
1155                  * Stop if:  (a) there are no more entries, or
1156                  * (b) we have inserted at least one entry and the
1157                  * next hash value is not a continuation
1158                  */
1159                 if ((ret == 0) ||
1160                     (count && ((hashval & 1) == 0)))
1161                         break;
1162         }
1163         dx_release(frames);
1164         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1165                        "next hash: %x\n", count, *next_hash));
1166         return count;
1167 errout:
1168         dx_release(frames);
1169         return (err);
1170 }
1171 
1172 static inline int search_dirblock(struct buffer_head *bh,
1173                                   struct inode *dir,
1174                                   struct ext4_filename *fname,
1175                                   unsigned int offset,
1176                                   struct ext4_dir_entry_2 **res_dir)
1177 {
1178         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1179                                fname, offset, res_dir);
1180 }
1181 
1182 /*
1183  * Directory block splitting, compacting
1184  */
1185 
1186 /*
1187  * Create map of hash values, offsets, and sizes, stored at end of block.
1188  * Returns number of entries mapped.
1189  */
1190 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
1191                        unsigned blocksize, struct dx_hash_info *hinfo,
1192                        struct dx_map_entry *map_tail)
1193 {
1194         int count = 0;
1195         char *base = (char *) de;
1196         struct dx_hash_info h = *hinfo;
1197 
1198         while ((char *) de < base + blocksize) {
1199                 if (de->name_len && de->inode) {
1200                         ext4fs_dirhash(de->name, de->name_len, &h);
1201                         map_tail--;
1202                         map_tail->hash = h.hash;
1203                         map_tail->offs = ((char *) de - base)>>2;
1204                         map_tail->size = le16_to_cpu(de->rec_len);
1205                         count++;
1206                         cond_resched();
1207                 }
1208                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1209                 de = ext4_next_entry(de, blocksize);
1210         }
1211         return count;
1212 }
1213 
1214 /* Sort map by hash value */
1215 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1216 {
1217         struct dx_map_entry *p, *q, *top = map + count - 1;
1218         int more;
1219         /* Combsort until bubble sort doesn't suck */
1220         while (count > 2) {
1221                 count = count*10/13;
1222                 if (count - 9 < 2) /* 9, 10 -> 11 */
1223                         count = 11;
1224                 for (p = top, q = p - count; q >= map; p--, q--)
1225                         if (p->hash < q->hash)
1226                                 swap(*p, *q);
1227         }
1228         /* Garden variety bubble sort */
1229         do {
1230                 more = 0;
1231                 q = top;
1232                 while (q-- > map) {
1233                         if (q[1].hash >= q[0].hash)
1234                                 continue;
1235                         swap(*(q+1), *q);
1236                         more = 1;
1237                 }
1238         } while(more);
1239 }
1240 
1241 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1242 {
1243         struct dx_entry *entries = frame->entries;
1244         struct dx_entry *old = frame->at, *new = old + 1;
1245         int count = dx_get_count(entries);
1246 
1247         assert(count < dx_get_limit(entries));
1248         assert(old < entries + count);
1249         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1250         dx_set_hash(new, hash);
1251         dx_set_block(new, block);
1252         dx_set_count(entries, count + 1);
1253 }
1254 
1255 /*
1256  * Test whether a directory entry matches the filename being searched for.
1257  *
1258  * Return: %true if the directory entry matches, otherwise %false.
1259  */
1260 static inline bool ext4_match(const struct ext4_filename *fname,
1261                               const struct ext4_dir_entry_2 *de)
1262 {
1263         struct fscrypt_name f;
1264 
1265         if (!de->inode)
1266                 return false;
1267 
1268         f.usr_fname = fname->usr_fname;
1269         f.disk_name = fname->disk_name;
1270 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1271         f.crypto_buf = fname->crypto_buf;
1272 #endif
1273         return fscrypt_match_name(&f, de->name, de->name_len);
1274 }
1275 
1276 /*
1277  * Returns 0 if not found, -1 on failure, and 1 on success
1278  */
1279 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1280                     struct inode *dir, struct ext4_filename *fname,
1281                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1282 {
1283         struct ext4_dir_entry_2 * de;
1284         char * dlimit;
1285         int de_len;
1286 
1287         de = (struct ext4_dir_entry_2 *)search_buf;
1288         dlimit = search_buf + buf_size;
1289         while ((char *) de < dlimit) {
1290                 /* this code is executed quadratically often */
1291                 /* do minimal checking `by hand' */
1292                 if ((char *) de + de->name_len <= dlimit &&
1293                     ext4_match(fname, de)) {
1294                         /* found a match - just to be sure, do
1295                          * a full check */
1296                         if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
1297                                                  bh->b_size, offset))
1298                                 return -1;
1299                         *res_dir = de;
1300                         return 1;
1301                 }
1302                 /* prevent looping on a bad block */
1303                 de_len = ext4_rec_len_from_disk(de->rec_len,
1304                                                 dir->i_sb->s_blocksize);
1305                 if (de_len <= 0)
1306                         return -1;
1307                 offset += de_len;
1308                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1309         }
1310         return 0;
1311 }
1312 
1313 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1314                                struct ext4_dir_entry *de)
1315 {
1316         struct super_block *sb = dir->i_sb;
1317 
1318         if (!is_dx(dir))
1319                 return 0;
1320         if (block == 0)
1321                 return 1;
1322         if (de->inode == 0 &&
1323             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1324                         sb->s_blocksize)
1325                 return 1;
1326         return 0;
1327 }
1328 
1329 /*
1330  *      ext4_find_entry()
1331  *
1332  * finds an entry in the specified directory with the wanted name. It
1333  * returns the cache buffer in which the entry was found, and the entry
1334  * itself (as a parameter - res_dir). It does NOT read the inode of the
1335  * entry - you'll have to do that yourself if you want to.
1336  *
1337  * The returned buffer_head has ->b_count elevated.  The caller is expected
1338  * to brelse() it when appropriate.
1339  */
1340 static struct buffer_head * ext4_find_entry (struct inode *dir,
1341                                         const struct qstr *d_name,
1342                                         struct ext4_dir_entry_2 **res_dir,
1343                                         int *inlined)
1344 {
1345         struct super_block *sb;
1346         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1347         struct buffer_head *bh, *ret = NULL;
1348         ext4_lblk_t start, block;
1349         const u8 *name = d_name->name;
1350         size_t ra_max = 0;      /* Number of bh's in the readahead
1351                                    buffer, bh_use[] */
1352         size_t ra_ptr = 0;      /* Current index into readahead
1353                                    buffer */
1354         ext4_lblk_t  nblocks;
1355         int i, namelen, retval;
1356         struct ext4_filename fname;
1357 
1358         *res_dir = NULL;
1359         sb = dir->i_sb;
1360         namelen = d_name->len;
1361         if (namelen > EXT4_NAME_LEN)
1362                 return NULL;
1363 
1364         retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1365         if (retval == -ENOENT)
1366                 return NULL;
1367         if (retval)
1368                 return ERR_PTR(retval);
1369 
1370         if (ext4_has_inline_data(dir)) {
1371                 int has_inline_data = 1;
1372                 ret = ext4_find_inline_entry(dir, &fname, res_dir,
1373                                              &has_inline_data);
1374                 if (has_inline_data) {
1375                         if (inlined)
1376                                 *inlined = 1;
1377                         goto cleanup_and_exit;
1378                 }
1379         }
1380 
1381         if ((namelen <= 2) && (name[0] == '.') &&
1382             (name[1] == '.' || name[1] == '\0')) {
1383                 /*
1384                  * "." or ".." will only be in the first block
1385                  * NFS may look up ".."; "." should be handled by the VFS
1386                  */
1387                 block = start = 0;
1388                 nblocks = 1;
1389                 goto restart;
1390         }
1391         if (is_dx(dir)) {
1392                 ret = ext4_dx_find_entry(dir, &fname, res_dir);
1393                 /*
1394                  * On success, or if the error was file not found,
1395                  * return.  Otherwise, fall back to doing a search the
1396                  * old fashioned way.
1397                  */
1398                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1399                         goto cleanup_and_exit;
1400                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1401                                "falling back\n"));
1402                 ret = NULL;
1403         }
1404         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1405         if (!nblocks) {
1406                 ret = NULL;
1407                 goto cleanup_and_exit;
1408         }
1409         start = EXT4_I(dir)->i_dir_start_lookup;
1410         if (start >= nblocks)
1411                 start = 0;
1412         block = start;
1413 restart:
1414         do {
1415                 /*
1416                  * We deal with the read-ahead logic here.
1417                  */
1418                 if (ra_ptr >= ra_max) {
1419                         /* Refill the readahead buffer */
1420                         ra_ptr = 0;
1421                         if (block < start)
1422                                 ra_max = start - block;
1423                         else
1424                                 ra_max = nblocks - block;
1425                         ra_max = min(ra_max, ARRAY_SIZE(bh_use));
1426                         retval = ext4_bread_batch(dir, block, ra_max,
1427                                                   false /* wait */, bh_use);
1428                         if (retval) {
1429                                 ret = ERR_PTR(retval);
1430                                 ra_max = 0;
1431                                 goto cleanup_and_exit;
1432                         }
1433                 }
1434                 if ((bh = bh_use[ra_ptr++]) == NULL)
1435                         goto next;
1436                 wait_on_buffer(bh);
1437                 if (!buffer_uptodate(bh)) {
1438                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1439                                          (unsigned long) block);
1440                         brelse(bh);
1441                         ret = ERR_PTR(-EIO);
1442                         goto cleanup_and_exit;
1443                 }
1444                 if (!buffer_verified(bh) &&
1445                     !is_dx_internal_node(dir, block,
1446                                          (struct ext4_dir_entry *)bh->b_data) &&
1447                     !ext4_dirent_csum_verify(dir,
1448                                 (struct ext4_dir_entry *)bh->b_data)) {
1449                         EXT4_ERROR_INODE(dir, "checksumming directory "
1450                                          "block %lu", (unsigned long)block);
1451                         brelse(bh);
1452                         ret = ERR_PTR(-EFSBADCRC);
1453                         goto cleanup_and_exit;
1454                 }
1455                 set_buffer_verified(bh);
1456                 i = search_dirblock(bh, dir, &fname,
1457                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1458                 if (i == 1) {
1459                         EXT4_I(dir)->i_dir_start_lookup = block;
1460                         ret = bh;
1461                         goto cleanup_and_exit;
1462                 } else {
1463                         brelse(bh);
1464                         if (i < 0)
1465                                 goto cleanup_and_exit;
1466                 }
1467         next:
1468                 if (++block >= nblocks)
1469                         block = 0;
1470         } while (block != start);
1471 
1472         /*
1473          * If the directory has grown while we were searching, then
1474          * search the last part of the directory before giving up.
1475          */
1476         block = nblocks;
1477         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1478         if (block < nblocks) {
1479                 start = 0;
1480                 goto restart;
1481         }
1482 
1483 cleanup_and_exit:
1484         /* Clean up the read-ahead blocks */
1485         for (; ra_ptr < ra_max; ra_ptr++)
1486                 brelse(bh_use[ra_ptr]);
1487         ext4_fname_free_filename(&fname);
1488         return ret;
1489 }
1490 
1491 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1492                         struct ext4_filename *fname,
1493                         struct ext4_dir_entry_2 **res_dir)
1494 {
1495         struct super_block * sb = dir->i_sb;
1496         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1497         struct buffer_head *bh;
1498         ext4_lblk_t block;
1499         int retval;
1500 
1501 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1502         *res_dir = NULL;
1503 #endif
1504         frame = dx_probe(fname, dir, NULL, frames);
1505         if (IS_ERR(frame))
1506                 return (struct buffer_head *) frame;
1507         do {
1508                 block = dx_get_block(frame->at);
1509                 bh = ext4_read_dirblock(dir, block, DIRENT);
1510                 if (IS_ERR(bh))
1511                         goto errout;
1512 
1513                 retval = search_dirblock(bh, dir, fname,
1514                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1515                                          res_dir);
1516                 if (retval == 1)
1517                         goto success;
1518                 brelse(bh);
1519                 if (retval == -1) {
1520                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1521                         goto errout;
1522                 }
1523 
1524                 /* Check to see if we should continue to search */
1525                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1526                                                frames, NULL);
1527                 if (retval < 0) {
1528                         ext4_warning_inode(dir,
1529                                 "error %d reading directory index block",
1530                                 retval);
1531                         bh = ERR_PTR(retval);
1532                         goto errout;
1533                 }
1534         } while (retval == 1);
1535 
1536         bh = NULL;
1537 errout:
1538         dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1539 success:
1540         dx_release(frames);
1541         return bh;
1542 }
1543 
1544 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1545 {
1546         struct inode *inode;
1547         struct ext4_dir_entry_2 *de;
1548         struct buffer_head *bh;
1549         int err;
1550 
1551         err = fscrypt_prepare_lookup(dir, dentry, flags);
1552         if (err)
1553                 return ERR_PTR(err);
1554 
1555         if (dentry->d_name.len > EXT4_NAME_LEN)
1556                 return ERR_PTR(-ENAMETOOLONG);
1557 
1558         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1559         if (IS_ERR(bh))
1560                 return ERR_CAST(bh);
1561         inode = NULL;
1562         if (bh) {
1563                 __u32 ino = le32_to_cpu(de->inode);
1564                 brelse(bh);
1565                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1566                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1567                         return ERR_PTR(-EFSCORRUPTED);
1568                 }
1569                 if (unlikely(ino == dir->i_ino)) {
1570                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1571                                          dentry);
1572                         return ERR_PTR(-EFSCORRUPTED);
1573                 }
1574                 inode = ext4_iget_normal(dir->i_sb, ino);
1575                 if (inode == ERR_PTR(-ESTALE)) {
1576                         EXT4_ERROR_INODE(dir,
1577                                          "deleted inode referenced: %u",
1578                                          ino);
1579                         return ERR_PTR(-EFSCORRUPTED);
1580                 }
1581                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1582                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1583                     !fscrypt_has_permitted_context(dir, inode)) {
1584                         ext4_warning(inode->i_sb,
1585                                      "Inconsistent encryption contexts: %lu/%lu",
1586                                      dir->i_ino, inode->i_ino);
1587                         iput(inode);
1588                         return ERR_PTR(-EPERM);
1589                 }
1590         }
1591         return d_splice_alias(inode, dentry);
1592 }
1593 
1594 
1595 struct dentry *ext4_get_parent(struct dentry *child)
1596 {
1597         __u32 ino;
1598         static const struct qstr dotdot = QSTR_INIT("..", 2);
1599         struct ext4_dir_entry_2 * de;
1600         struct buffer_head *bh;
1601 
1602         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1603         if (IS_ERR(bh))
1604                 return ERR_CAST(bh);
1605         if (!bh)
1606                 return ERR_PTR(-ENOENT);
1607         ino = le32_to_cpu(de->inode);
1608         brelse(bh);
1609 
1610         if (!ext4_valid_inum(child->d_sb, ino)) {
1611                 EXT4_ERROR_INODE(d_inode(child),
1612                                  "bad parent inode number: %u", ino);
1613                 return ERR_PTR(-EFSCORRUPTED);
1614         }
1615 
1616         return d_obtain_alias(ext4_iget_normal(child->d_sb, ino));
1617 }
1618 
1619 /*
1620  * Move count entries from end of map between two memory locations.
1621  * Returns pointer to last entry moved.
1622  */
1623 static struct ext4_dir_entry_2 *
1624 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1625                 unsigned blocksize)
1626 {
1627         unsigned rec_len = 0;
1628 
1629         while (count--) {
1630                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1631                                                 (from + (map->offs<<2));
1632                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1633                 memcpy (to, de, rec_len);
1634                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1635                                 ext4_rec_len_to_disk(rec_len, blocksize);
1636                 de->inode = 0;
1637                 map++;
1638                 to += rec_len;
1639         }
1640         return (struct ext4_dir_entry_2 *) (to - rec_len);
1641 }
1642 
1643 /*
1644  * Compact each dir entry in the range to the minimal rec_len.
1645  * Returns pointer to last entry in range.
1646  */
1647 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1648 {
1649         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1650         unsigned rec_len = 0;
1651 
1652         prev = to = de;
1653         while ((char*)de < base + blocksize) {
1654                 next = ext4_next_entry(de, blocksize);
1655                 if (de->inode && de->name_len) {
1656                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1657                         if (de > to)
1658                                 memmove(to, de, rec_len);
1659                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1660                         prev = to;
1661                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1662                 }
1663                 de = next;
1664         }
1665         return prev;
1666 }
1667 
1668 /*
1669  * Split a full leaf block to make room for a new dir entry.
1670  * Allocate a new block, and move entries so that they are approx. equally full.
1671  * Returns pointer to de in block into which the new entry will be inserted.
1672  */
1673 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1674                         struct buffer_head **bh,struct dx_frame *frame,
1675                         struct dx_hash_info *hinfo)
1676 {
1677         unsigned blocksize = dir->i_sb->s_blocksize;
1678         unsigned count, continued;
1679         struct buffer_head *bh2;
1680         ext4_lblk_t newblock;
1681         u32 hash2;
1682         struct dx_map_entry *map;
1683         char *data1 = (*bh)->b_data, *data2;
1684         unsigned split, move, size;
1685         struct ext4_dir_entry_2 *de = NULL, *de2;
1686         struct ext4_dir_entry_tail *t;
1687         int     csum_size = 0;
1688         int     err = 0, i;
1689 
1690         if (ext4_has_metadata_csum(dir->i_sb))
1691                 csum_size = sizeof(struct ext4_dir_entry_tail);
1692 
1693         bh2 = ext4_append(handle, dir, &newblock);
1694         if (IS_ERR(bh2)) {
1695                 brelse(*bh);
1696                 *bh = NULL;
1697                 return (struct ext4_dir_entry_2 *) bh2;
1698         }
1699 
1700         BUFFER_TRACE(*bh, "get_write_access");
1701         err = ext4_journal_get_write_access(handle, *bh);
1702         if (err)
1703                 goto journal_error;
1704 
1705         BUFFER_TRACE(frame->bh, "get_write_access");
1706         err = ext4_journal_get_write_access(handle, frame->bh);
1707         if (err)
1708                 goto journal_error;
1709 
1710         data2 = bh2->b_data;
1711 
1712         /* create map in the end of data2 block */
1713         map = (struct dx_map_entry *) (data2 + blocksize);
1714         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1715                              blocksize, hinfo, map);
1716         map -= count;
1717         dx_sort_map(map, count);
1718         /* Split the existing block in the middle, size-wise */
1719         size = 0;
1720         move = 0;
1721         for (i = count-1; i >= 0; i--) {
1722                 /* is more than half of this entry in 2nd half of the block? */
1723                 if (size + map[i].size/2 > blocksize/2)
1724                         break;
1725                 size += map[i].size;
1726                 move++;
1727         }
1728         /* map index at which we will split */
1729         split = count - move;
1730         hash2 = map[split].hash;
1731         continued = hash2 == map[split - 1].hash;
1732         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1733                         (unsigned long)dx_get_block(frame->at),
1734                                         hash2, split, count-split));
1735 
1736         /* Fancy dance to stay within two buffers */
1737         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1738                               blocksize);
1739         de = dx_pack_dirents(data1, blocksize);
1740         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1741                                            (char *) de,
1742                                            blocksize);
1743         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1744                                             (char *) de2,
1745                                             blocksize);
1746         if (csum_size) {
1747                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1748                 initialize_dirent_tail(t, blocksize);
1749 
1750                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1751                 initialize_dirent_tail(t, blocksize);
1752         }
1753 
1754         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1755                         blocksize, 1));
1756         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1757                         blocksize, 1));
1758 
1759         /* Which block gets the new entry? */
1760         if (hinfo->hash >= hash2) {
1761                 swap(*bh, bh2);
1762                 de = de2;
1763         }
1764         dx_insert_block(frame, hash2 + continued, newblock);
1765         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1766         if (err)
1767                 goto journal_error;
1768         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1769         if (err)
1770                 goto journal_error;
1771         brelse(bh2);
1772         dxtrace(dx_show_index("frame", frame->entries));
1773         return de;
1774 
1775 journal_error:
1776         brelse(*bh);
1777         brelse(bh2);
1778         *bh = NULL;
1779         ext4_std_error(dir->i_sb, err);
1780         return ERR_PTR(err);
1781 }
1782 
1783 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1784                       struct buffer_head *bh,
1785                       void *buf, int buf_size,
1786                       struct ext4_filename *fname,
1787                       struct ext4_dir_entry_2 **dest_de)
1788 {
1789         struct ext4_dir_entry_2 *de;
1790         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1791         int nlen, rlen;
1792         unsigned int offset = 0;
1793         char *top;
1794 
1795         de = (struct ext4_dir_entry_2 *)buf;
1796         top = buf + buf_size - reclen;
1797         while ((char *) de <= top) {
1798                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1799                                          buf, buf_size, offset))
1800                         return -EFSCORRUPTED;
1801                 if (ext4_match(fname, de))
1802                         return -EEXIST;
1803                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1804                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1805                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1806                         break;
1807                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1808                 offset += rlen;
1809         }
1810         if ((char *) de > top)
1811                 return -ENOSPC;
1812 
1813         *dest_de = de;
1814         return 0;
1815 }
1816 
1817 void ext4_insert_dentry(struct inode *inode,
1818                         struct ext4_dir_entry_2 *de,
1819                         int buf_size,
1820                         struct ext4_filename *fname)
1821 {
1822 
1823         int nlen, rlen;
1824 
1825         nlen = EXT4_DIR_REC_LEN(de->name_len);
1826         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1827         if (de->inode) {
1828                 struct ext4_dir_entry_2 *de1 =
1829                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1830                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1831                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1832                 de = de1;
1833         }
1834         de->file_type = EXT4_FT_UNKNOWN;
1835         de->inode = cpu_to_le32(inode->i_ino);
1836         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1837         de->name_len = fname_len(fname);
1838         memcpy(de->name, fname_name(fname), fname_len(fname));
1839 }
1840 
1841 /*
1842  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1843  * it points to a directory entry which is guaranteed to be large
1844  * enough for new directory entry.  If de is NULL, then
1845  * add_dirent_to_buf will attempt search the directory block for
1846  * space.  It will return -ENOSPC if no space is available, and -EIO
1847  * and -EEXIST if directory entry already exists.
1848  */
1849 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1850                              struct inode *dir,
1851                              struct inode *inode, struct ext4_dir_entry_2 *de,
1852                              struct buffer_head *bh)
1853 {
1854         unsigned int    blocksize = dir->i_sb->s_blocksize;
1855         int             csum_size = 0;
1856         int             err;
1857 
1858         if (ext4_has_metadata_csum(inode->i_sb))
1859                 csum_size = sizeof(struct ext4_dir_entry_tail);
1860 
1861         if (!de) {
1862                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1863                                         blocksize - csum_size, fname, &de);
1864                 if (err)
1865                         return err;
1866         }
1867         BUFFER_TRACE(bh, "get_write_access");
1868         err = ext4_journal_get_write_access(handle, bh);
1869         if (err) {
1870                 ext4_std_error(dir->i_sb, err);
1871                 return err;
1872         }
1873 
1874         /* By now the buffer is marked for journaling */
1875         ext4_insert_dentry(inode, de, blocksize, fname);
1876 
1877         /*
1878          * XXX shouldn't update any times until successful
1879          * completion of syscall, but too many callers depend
1880          * on this.
1881          *
1882          * XXX similarly, too many callers depend on
1883          * ext4_new_inode() setting the times, but error
1884          * recovery deletes the inode, so the worst that can
1885          * happen is that the times are slightly out of date
1886          * and/or different from the directory change time.
1887          */
1888         dir->i_mtime = dir->i_ctime = current_time(dir);
1889         ext4_update_dx_flag(dir);
1890         inode_inc_iversion(dir);
1891         ext4_mark_inode_dirty(handle, dir);
1892         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1893         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1894         if (err)
1895                 ext4_std_error(dir->i_sb, err);
1896         return 0;
1897 }
1898 
1899 /*
1900  * This converts a one block unindexed directory to a 3 block indexed
1901  * directory, and adds the dentry to the indexed directory.
1902  */
1903 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1904                             struct inode *dir,
1905                             struct inode *inode, struct buffer_head *bh)
1906 {
1907         struct buffer_head *bh2;
1908         struct dx_root  *root;
1909         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1910         struct dx_entry *entries;
1911         struct ext4_dir_entry_2 *de, *de2;
1912         struct ext4_dir_entry_tail *t;
1913         char            *data1, *top;
1914         unsigned        len;
1915         int             retval;
1916         unsigned        blocksize;
1917         ext4_lblk_t  block;
1918         struct fake_dirent *fde;
1919         int csum_size = 0;
1920 
1921         if (ext4_has_metadata_csum(inode->i_sb))
1922                 csum_size = sizeof(struct ext4_dir_entry_tail);
1923 
1924         blocksize =  dir->i_sb->s_blocksize;
1925         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1926         BUFFER_TRACE(bh, "get_write_access");
1927         retval = ext4_journal_get_write_access(handle, bh);
1928         if (retval) {
1929                 ext4_std_error(dir->i_sb, retval);
1930                 brelse(bh);
1931                 return retval;
1932         }
1933         root = (struct dx_root *) bh->b_data;
1934 
1935         /* The 0th block becomes the root, move the dirents out */
1936         fde = &root->dotdot;
1937         de = (struct ext4_dir_entry_2 *)((char *)fde +
1938                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1939         if ((char *) de >= (((char *) root) + blocksize)) {
1940                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1941                 brelse(bh);
1942                 return -EFSCORRUPTED;
1943         }
1944         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1945 
1946         /* Allocate new block for the 0th block's dirents */
1947         bh2 = ext4_append(handle, dir, &block);
1948         if (IS_ERR(bh2)) {
1949                 brelse(bh);
1950                 return PTR_ERR(bh2);
1951         }
1952         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1953         data1 = bh2->b_data;
1954 
1955         memcpy (data1, de, len);
1956         de = (struct ext4_dir_entry_2 *) data1;
1957         top = data1 + len;
1958         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1959                 de = de2;
1960         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1961                                            (char *) de,
1962                                            blocksize);
1963 
1964         if (csum_size) {
1965                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1966                 initialize_dirent_tail(t, blocksize);
1967         }
1968 
1969         /* Initialize the root; the dot dirents already exist */
1970         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1971         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
1972                                            blocksize);
1973         memset (&root->info, 0, sizeof(root->info));
1974         root->info.info_length = sizeof(root->info);
1975         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1976         entries = root->entries;
1977         dx_set_block(entries, 1);
1978         dx_set_count(entries, 1);
1979         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
1980 
1981         /* Initialize as for dx_probe */
1982         fname->hinfo.hash_version = root->info.hash_version;
1983         if (fname->hinfo.hash_version <= DX_HASH_TEA)
1984                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
1985         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1986         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
1987 
1988         memset(frames, 0, sizeof(frames));
1989         frame = frames;
1990         frame->entries = entries;
1991         frame->at = entries;
1992         frame->bh = bh;
1993 
1994         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1995         if (retval)
1996                 goto out_frames;        
1997         retval = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1998         if (retval)
1999                 goto out_frames;        
2000 
2001         de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
2002         if (IS_ERR(de)) {
2003                 retval = PTR_ERR(de);
2004                 goto out_frames;
2005         }
2006 
2007         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2008 out_frames:
2009         /*
2010          * Even if the block split failed, we have to properly write
2011          * out all the changes we did so far. Otherwise we can end up
2012          * with corrupted filesystem.
2013          */
2014         if (retval)
2015                 ext4_mark_inode_dirty(handle, dir);
2016         dx_release(frames);
2017         brelse(bh2);
2018         return retval;
2019 }
2020 
2021 /*
2022  *      ext4_add_entry()
2023  *
2024  * adds a file entry to the specified directory, using the same
2025  * semantics as ext4_find_entry(). It returns NULL if it failed.
2026  *
2027  * NOTE!! The inode part of 'de' is left at 0 - which means you
2028  * may not sleep between calling this and putting something into
2029  * the entry, as someone else might have used it while you slept.
2030  */
2031 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2032                           struct inode *inode)
2033 {
2034         struct inode *dir = d_inode(dentry->d_parent);
2035         struct buffer_head *bh = NULL;
2036         struct ext4_dir_entry_2 *de;
2037         struct ext4_dir_entry_tail *t;
2038         struct super_block *sb;
2039         struct ext4_filename fname;
2040         int     retval;
2041         int     dx_fallback=0;
2042         unsigned blocksize;
2043         ext4_lblk_t block, blocks;
2044         int     csum_size = 0;
2045 
2046         if (ext4_has_metadata_csum(inode->i_sb))
2047                 csum_size = sizeof(struct ext4_dir_entry_tail);
2048 
2049         sb = dir->i_sb;
2050         blocksize = sb->s_blocksize;
2051         if (!dentry->d_name.len)
2052                 return -EINVAL;
2053 
2054         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2055         if (retval)
2056                 return retval;
2057 
2058         if (ext4_has_inline_data(dir)) {
2059                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2060                 if (retval < 0)
2061                         goto out;
2062                 if (retval == 1) {
2063                         retval = 0;
2064                         goto out;
2065                 }
2066         }
2067 
2068         if (is_dx(dir)) {
2069                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2070                 if (!retval || (retval != ERR_BAD_DX_DIR))
2071                         goto out;
2072                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2073                 dx_fallback++;
2074                 ext4_mark_inode_dirty(handle, dir);
2075         }
2076         blocks = dir->i_size >> sb->s_blocksize_bits;
2077         for (block = 0; block < blocks; block++) {
2078                 bh = ext4_read_dirblock(dir, block, DIRENT);
2079                 if (IS_ERR(bh)) {
2080                         retval = PTR_ERR(bh);
2081                         bh = NULL;
2082                         goto out;
2083                 }
2084                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2085                                            NULL, bh);
2086                 if (retval != -ENOSPC)
2087                         goto out;
2088 
2089                 if (blocks == 1 && !dx_fallback &&
2090                     ext4_has_feature_dir_index(sb)) {
2091                         retval = make_indexed_dir(handle, &fname, dir,
2092                                                   inode, bh);
2093                         bh = NULL; /* make_indexed_dir releases bh */
2094                         goto out;
2095                 }
2096                 brelse(bh);
2097         }
2098         bh = ext4_append(handle, dir, &block);
2099         if (IS_ERR(bh)) {
2100                 retval = PTR_ERR(bh);
2101                 bh = NULL;
2102                 goto out;
2103         }
2104         de = (struct ext4_dir_entry_2 *) bh->b_data;
2105         de->inode = 0;
2106         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2107 
2108         if (csum_size) {
2109                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2110                 initialize_dirent_tail(t, blocksize);
2111         }
2112 
2113         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2114 out:
2115         ext4_fname_free_filename(&fname);
2116         brelse(bh);
2117         if (retval == 0)
2118                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2119         return retval;
2120 }
2121 
2122 /*
2123  * Returns 0 for success, or a negative error value
2124  */
2125 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2126                              struct inode *dir, struct inode *inode)
2127 {
2128         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2129         struct dx_entry *entries, *at;
2130         struct buffer_head *bh;
2131         struct super_block *sb = dir->i_sb;
2132         struct ext4_dir_entry_2 *de;
2133         int restart;
2134         int err;
2135 
2136 again:
2137         restart = 0;
2138         frame = dx_probe(fname, dir, NULL, frames);
2139         if (IS_ERR(frame))
2140                 return PTR_ERR(frame);
2141         entries = frame->entries;
2142         at = frame->at;
2143         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2144         if (IS_ERR(bh)) {
2145                 err = PTR_ERR(bh);
2146                 bh = NULL;
2147                 goto cleanup;
2148         }
2149 
2150         BUFFER_TRACE(bh, "get_write_access");
2151         err = ext4_journal_get_write_access(handle, bh);
2152         if (err)
2153                 goto journal_error;
2154 
2155         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2156         if (err != -ENOSPC)
2157                 goto cleanup;
2158 
2159         err = 0;
2160         /* Block full, should compress but for now just split */
2161         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2162                        dx_get_count(entries), dx_get_limit(entries)));
2163         /* Need to split index? */
2164         if (dx_get_count(entries) == dx_get_limit(entries)) {
2165                 ext4_lblk_t newblock;
2166                 int levels = frame - frames + 1;
2167                 unsigned int icount;
2168                 int add_level = 1;
2169                 struct dx_entry *entries2;
2170                 struct dx_node *node2;
2171                 struct buffer_head *bh2;
2172 
2173                 while (frame > frames) {
2174                         if (dx_get_count((frame - 1)->entries) <
2175                             dx_get_limit((frame - 1)->entries)) {
2176                                 add_level = 0;
2177                                 break;
2178                         }
2179                         frame--; /* split higher index block */
2180                         at = frame->at;
2181                         entries = frame->entries;
2182                         restart = 1;
2183                 }
2184                 if (add_level && levels == ext4_dir_htree_level(sb)) {
2185                         ext4_warning(sb, "Directory (ino: %lu) index full, "
2186                                          "reach max htree level :%d",
2187                                          dir->i_ino, levels);
2188                         if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
2189                                 ext4_warning(sb, "Large directory feature is "
2190                                                  "not enabled on this "
2191                                                  "filesystem");
2192                         }
2193                         err = -ENOSPC;
2194                         goto cleanup;
2195                 }
2196                 icount = dx_get_count(entries);
2197                 bh2 = ext4_append(handle, dir, &newblock);
2198                 if (IS_ERR(bh2)) {
2199                         err = PTR_ERR(bh2);
2200                         goto cleanup;
2201                 }
2202                 node2 = (struct dx_node *)(bh2->b_data);
2203                 entries2 = node2->entries;
2204                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2205                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2206                                                            sb->s_blocksize);
2207                 BUFFER_TRACE(frame->bh, "get_write_access");
2208                 err = ext4_journal_get_write_access(handle, frame->bh);
2209                 if (err)
2210                         goto journal_error;
2211                 if (!add_level) {
2212                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2213                         unsigned hash2 = dx_get_hash(entries + icount1);
2214                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2215                                        icount1, icount2));
2216 
2217                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2218                         err = ext4_journal_get_write_access(handle,
2219                                                              (frame - 1)->bh);
2220                         if (err)
2221                                 goto journal_error;
2222 
2223                         memcpy((char *) entries2, (char *) (entries + icount1),
2224                                icount2 * sizeof(struct dx_entry));
2225                         dx_set_count(entries, icount1);
2226                         dx_set_count(entries2, icount2);
2227                         dx_set_limit(entries2, dx_node_limit(dir));
2228 
2229                         /* Which index block gets the new entry? */
2230                         if (at - entries >= icount1) {
2231                                 frame->at = at = at - entries - icount1 + entries2;
2232                                 frame->entries = entries = entries2;
2233                                 swap(frame->bh, bh2);
2234                         }
2235                         dx_insert_block((frame - 1), hash2, newblock);
2236                         dxtrace(dx_show_index("node", frame->entries));
2237                         dxtrace(dx_show_index("node",
2238                                ((struct dx_node *) bh2->b_data)->entries));
2239                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2240                         if (err)
2241                                 goto journal_error;
2242                         brelse (bh2);
2243                         err = ext4_handle_dirty_dx_node(handle, dir,
2244                                                    (frame - 1)->bh);
2245                         if (err)
2246                                 goto journal_error;
2247                         if (restart) {
2248                                 err = ext4_handle_dirty_dx_node(handle, dir,
2249                                                            frame->bh);
2250                                 goto journal_error;
2251                         }
2252                 } else {
2253                         struct dx_root *dxroot;
2254                         memcpy((char *) entries2, (char *) entries,
2255                                icount * sizeof(struct dx_entry));
2256                         dx_set_limit(entries2, dx_node_limit(dir));
2257 
2258                         /* Set up root */
2259                         dx_set_count(entries, 1);
2260                         dx_set_block(entries + 0, newblock);
2261                         dxroot = (struct dx_root *)frames[0].bh->b_data;
2262                         dxroot->info.indirect_levels += 1;
2263                         dxtrace(printk(KERN_DEBUG
2264                                        "Creating %d level index...\n",
2265                                        dxroot->info.indirect_levels));
2266                         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2267                         if (err)
2268                                 goto journal_error;
2269                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2270                         brelse(bh2);
2271                         restart = 1;
2272                         goto journal_error;
2273                 }
2274         }
2275         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2276         if (IS_ERR(de)) {
2277                 err = PTR_ERR(de);
2278                 goto cleanup;
2279         }
2280         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2281         goto cleanup;
2282 
2283 journal_error:
2284         ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
2285 cleanup:
2286         brelse(bh);
2287         dx_release(frames);
2288         /* @restart is true means htree-path has been changed, we need to
2289          * repeat dx_probe() to find out valid htree-path
2290          */
2291         if (restart && err == 0)
2292                 goto again;
2293         return err;
2294 }
2295 
2296 /*
2297  * ext4_generic_delete_entry deletes a directory entry by merging it
2298  * with the previous entry
2299  */
2300 int ext4_generic_delete_entry(handle_t *handle,
2301                               struct inode *dir,
2302                               struct ext4_dir_entry_2 *de_del,
2303                               struct buffer_head *bh,
2304                               void *entry_buf,
2305                               int buf_size,
2306                               int csum_size)
2307 {
2308         struct ext4_dir_entry_2 *de, *pde;
2309         unsigned int blocksize = dir->i_sb->s_blocksize;
2310         int i;
2311 
2312         i = 0;
2313         pde = NULL;
2314         de = (struct ext4_dir_entry_2 *)entry_buf;
2315         while (i < buf_size - csum_size) {
2316                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2317                                          bh->b_data, bh->b_size, i))
2318                         return -EFSCORRUPTED;
2319                 if (de == de_del)  {
2320                         if (pde)
2321                                 pde->rec_len = ext4_rec_len_to_disk(
2322                                         ext4_rec_len_from_disk(pde->rec_len,
2323                                                                blocksize) +
2324                                         ext4_rec_len_from_disk(de->rec_len,
2325                                                                blocksize),
2326                                         blocksize);
2327                         else
2328                                 de->inode = 0;
2329                         inode_inc_iversion(dir);
2330                         return 0;
2331                 }
2332                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2333                 pde = de;
2334                 de = ext4_next_entry(de, blocksize);
2335         }
2336         return -ENOENT;
2337 }
2338 
2339 static int ext4_delete_entry(handle_t *handle,
2340                              struct inode *dir,
2341                              struct ext4_dir_entry_2 *de_del,
2342                              struct buffer_head *bh)
2343 {
2344         int err, csum_size = 0;
2345 
2346         if (ext4_has_inline_data(dir)) {
2347                 int has_inline_data = 1;
2348                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2349                                                &has_inline_data);
2350                 if (has_inline_data)
2351                         return err;
2352         }
2353 
2354         if (ext4_has_metadata_csum(dir->i_sb))
2355                 csum_size = sizeof(struct ext4_dir_entry_tail);
2356 
2357         BUFFER_TRACE(bh, "get_write_access");
2358         err = ext4_journal_get_write_access(handle, bh);
2359         if (unlikely(err))
2360                 goto out;
2361 
2362         err = ext4_generic_delete_entry(handle, dir, de_del,
2363                                         bh, bh->b_data,
2364                                         dir->i_sb->s_blocksize, csum_size);
2365         if (err)
2366                 goto out;
2367 
2368         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2369         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2370         if (unlikely(err))
2371                 goto out;
2372 
2373         return 0;
2374 out:
2375         if (err != -ENOENT)
2376                 ext4_std_error(dir->i_sb, err);
2377         return err;
2378 }
2379 
2380 /*
2381  * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
2382  * since this indicates that nlinks count was previously 1 to avoid overflowing
2383  * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
2384  * that subdirectory link counts are not being maintained accurately.
2385  *
2386  * The caller has already checked for i_nlink overflow in case the DIR_LINK
2387  * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
2388  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
2389  * on regular files) and to avoid creating huge/slow non-HTREE directories.
2390  */
2391 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2392 {
2393         inc_nlink(inode);
2394         if (is_dx(inode) &&
2395             (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
2396                 set_nlink(inode, 1);
2397 }
2398 
2399 /*
2400  * If a directory had nlink == 1, then we should let it be 1. This indicates
2401  * directory has >EXT4_LINK_MAX subdirs.
2402  */
2403 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2404 {
2405         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2406                 drop_nlink(inode);
2407 }
2408 
2409 
2410 static int ext4_add_nondir(handle_t *handle,
2411                 struct dentry *dentry, struct inode *inode)
2412 {
2413         int err = ext4_add_entry(handle, dentry, inode);
2414         if (!err) {
2415                 ext4_mark_inode_dirty(handle, inode);
2416                 d_instantiate_new(dentry, inode);
2417                 return 0;
2418         }
2419         drop_nlink(inode);
2420         unlock_new_inode(inode);
2421         iput(inode);
2422         return err;
2423 }
2424 
2425 /*
2426  * By the time this is called, we already have created
2427  * the directory cache entry for the new file, but it
2428  * is so far negative - it has no inode.
2429  *
2430  * If the create succeeds, we fill in the inode information
2431  * with d_instantiate().
2432  */
2433 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2434                        bool excl)
2435 {
2436         handle_t *handle;
2437         struct inode *inode;
2438         int err, credits, retries = 0;
2439 
2440         err = dquot_initialize(dir);
2441         if (err)
2442                 return err;
2443 
2444         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2445                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2446 retry:
2447         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2448                                             NULL, EXT4_HT_DIR, credits);
2449         handle = ext4_journal_current_handle();
2450         err = PTR_ERR(inode);
2451         if (!IS_ERR(inode)) {
2452                 inode->i_op = &ext4_file_inode_operations;
2453                 inode->i_fop = &ext4_file_operations;
2454                 ext4_set_aops(inode);
2455                 err = ext4_add_nondir(handle, dentry, inode);
2456                 if (!err && IS_DIRSYNC(dir))
2457                         ext4_handle_sync(handle);
2458         }
2459         if (handle)
2460                 ext4_journal_stop(handle);
2461         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2462                 goto retry;
2463         return err;
2464 }
2465 
2466 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2467                       umode_t mode, dev_t rdev)
2468 {
2469         handle_t *handle;
2470         struct inode *inode;
2471         int err, credits, retries = 0;
2472 
2473         err = dquot_initialize(dir);
2474         if (err)
2475                 return err;
2476 
2477         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2478                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2479 retry:
2480         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2481                                             NULL, EXT4_HT_DIR, credits);
2482         handle = ext4_journal_current_handle();
2483         err = PTR_ERR(inode);
2484         if (!IS_ERR(inode)) {
2485                 init_special_inode(inode, inode->i_mode, rdev);
2486                 inode->i_op = &ext4_special_inode_operations;
2487                 err = ext4_add_nondir(handle, dentry, inode);
2488                 if (!err && IS_DIRSYNC(dir))
2489                         ext4_handle_sync(handle);
2490         }
2491         if (handle)
2492                 ext4_journal_stop(handle);
2493         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2494                 goto retry;
2495         return err;
2496 }
2497 
2498 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2499 {
2500         handle_t *handle;
2501         struct inode *inode;
2502         int err, retries = 0;
2503 
2504         err = dquot_initialize(dir);
2505         if (err)
2506                 return err;
2507 
2508 retry:
2509         inode = ext4_new_inode_start_handle(dir, mode,
2510                                             NULL, 0, NULL,
2511                                             EXT4_HT_DIR,
2512                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2513                           4 + EXT4_XATTR_TRANS_BLOCKS);
2514         handle = ext4_journal_current_handle();
2515         err = PTR_ERR(inode);
2516         if (!IS_ERR(inode)) {
2517                 inode->i_op = &ext4_file_inode_operations;
2518                 inode->i_fop = &ext4_file_operations;
2519                 ext4_set_aops(inode);
2520                 d_tmpfile(dentry, inode);
2521                 err = ext4_orphan_add(handle, inode);
2522                 if (err)
2523                         goto err_unlock_inode;
2524                 mark_inode_dirty(inode);
2525                 unlock_new_inode(inode);
2526         }
2527         if (handle)
2528                 ext4_journal_stop(handle);
2529         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2530                 goto retry;
2531         return err;
2532 err_unlock_inode:
2533         ext4_journal_stop(handle);
2534         unlock_new_inode(inode);
2535         return err;
2536 }
2537 
2538 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2539                           struct ext4_dir_entry_2 *de,
2540                           int blocksize, int csum_size,
2541                           unsigned int parent_ino, int dotdot_real_len)
2542 {
2543         de->inode = cpu_to_le32(inode->i_ino);
2544         de->name_len = 1;
2545         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2546                                            blocksize);
2547         strcpy(de->name, ".");
2548         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2549 
2550         de = ext4_next_entry(de, blocksize);
2551         de->inode = cpu_to_le32(parent_ino);
2552         de->name_len = 2;
2553         if (!dotdot_real_len)
2554                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2555                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2556                                         blocksize);
2557         else
2558                 de->rec_len = ext4_rec_len_to_disk(
2559                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2560         strcpy(de->name, "..");
2561         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2562 
2563         return ext4_next_entry(de, blocksize);
2564 }
2565 
2566 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2567                              struct inode *inode)
2568 {
2569         struct buffer_head *dir_block = NULL;
2570         struct ext4_dir_entry_2 *de;
2571         struct ext4_dir_entry_tail *t;
2572         ext4_lblk_t block = 0;
2573         unsigned int blocksize = dir->i_sb->s_blocksize;
2574         int csum_size = 0;
2575         int err;
2576 
2577         if (ext4_has_metadata_csum(dir->i_sb))
2578                 csum_size = sizeof(struct ext4_dir_entry_tail);
2579 
2580         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2581                 err = ext4_try_create_inline_dir(handle, dir, inode);
2582                 if (err < 0 && err != -ENOSPC)
2583                         goto out;
2584                 if (!err)
2585                         goto out;
2586         }
2587 
2588         inode->i_size = 0;
2589         dir_block = ext4_append(handle, inode, &block);
2590         if (IS_ERR(dir_block))
2591                 return PTR_ERR(dir_block);
2592         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2593         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2594         set_nlink(inode, 2);
2595         if (csum_size) {
2596                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2597                 initialize_dirent_tail(t, blocksize);
2598         }
2599 
2600         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2601         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2602         if (err)
2603                 goto out;
2604         set_buffer_verified(dir_block);
2605 out:
2606         brelse(dir_block);
2607         return err;
2608 }
2609 
2610 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2611 {
2612         handle_t *handle;
2613         struct inode *inode;
2614         int err, credits, retries = 0;
2615 
2616         if (EXT4_DIR_LINK_MAX(dir))
2617                 return -EMLINK;
2618 
2619         err = dquot_initialize(dir);
2620         if (err)
2621                 return err;
2622 
2623         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2624                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2625 retry:
2626         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2627                                             &dentry->d_name,
2628                                             0, NULL, EXT4_HT_DIR, credits);
2629         handle = ext4_journal_current_handle();
2630         err = PTR_ERR(inode);
2631         if (IS_ERR(inode))
2632                 goto out_stop;
2633 
2634         inode->i_op = &ext4_dir_inode_operations;
2635         inode->i_fop = &ext4_dir_operations;
2636         err = ext4_init_new_dir(handle, dir, inode);
2637         if (err)
2638                 goto out_clear_inode;
2639         err = ext4_mark_inode_dirty(handle, inode);
2640         if (!err)
2641                 err = ext4_add_entry(handle, dentry, inode);
2642         if (err) {
2643 out_clear_inode:
2644                 clear_nlink(inode);
2645                 unlock_new_inode(inode);
2646                 ext4_mark_inode_dirty(handle, inode);
2647                 iput(inode);
2648                 goto out_stop;
2649         }
2650         ext4_inc_count(handle, dir);
2651         ext4_update_dx_flag(dir);
2652         err = ext4_mark_inode_dirty(handle, dir);
2653         if (err)
2654                 goto out_clear_inode;
2655         d_instantiate_new(dentry, inode);
2656         if (IS_DIRSYNC(dir))
2657                 ext4_handle_sync(handle);
2658 
2659 out_stop:
2660         if (handle)
2661                 ext4_journal_stop(handle);
2662         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2663                 goto retry;
2664         return err;
2665 }
2666 
2667 /*
2668  * routine to check that the specified directory is empty (for rmdir)
2669  */
2670 bool ext4_empty_dir(struct inode *inode)
2671 {
2672         unsigned int offset;
2673         struct buffer_head *bh;
2674         struct ext4_dir_entry_2 *de, *de1;
2675         struct super_block *sb;
2676 
2677         if (ext4_has_inline_data(inode)) {
2678                 int has_inline_data = 1;
2679                 int ret;
2680 
2681                 ret = empty_inline_dir(inode, &has_inline_data);
2682                 if (has_inline_data)
2683                         return ret;
2684         }
2685 
2686         sb = inode->i_sb;
2687         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2688                 EXT4_ERROR_INODE(inode, "invalid size");
2689                 return true;
2690         }
2691         bh = ext4_read_dirblock(inode, 0, EITHER);
2692         if (IS_ERR(bh))
2693                 return true;
2694 
2695         de = (struct ext4_dir_entry_2 *) bh->b_data;
2696         de1 = ext4_next_entry(de, sb->s_blocksize);
2697         if (le32_to_cpu(de->inode) != inode->i_ino ||
2698                         le32_to_cpu(de1->inode) == 0 ||
2699                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2700                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2701                 brelse(bh);
2702                 return true;
2703         }
2704         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2705                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2706         de = ext4_next_entry(de1, sb->s_blocksize);
2707         while (offset < inode->i_size) {
2708                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2709                         unsigned int lblock;
2710                         brelse(bh);
2711                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2712                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2713                         if (IS_ERR(bh))
2714                                 return true;
2715                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2716                 }
2717                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2718                                          bh->b_data, bh->b_size, offset)) {
2719                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2720                                                          sb->s_blocksize);
2721                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2722                         continue;
2723                 }
2724                 if (le32_to_cpu(de->inode)) {
2725                         brelse(bh);
2726                         return false;
2727                 }
2728                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2729                 de = ext4_next_entry(de, sb->s_blocksize);
2730         }
2731         brelse(bh);
2732         return true;
2733 }
2734 
2735 /*
2736  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2737  * such inodes, starting at the superblock, in case we crash before the
2738  * file is closed/deleted, or in case the inode truncate spans multiple
2739  * transactions and the last transaction is not recovered after a crash.
2740  *
2741  * At filesystem recovery time, we walk this list deleting unlinked
2742  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2743  *
2744  * Orphan list manipulation functions must be called under i_mutex unless
2745  * we are just creating the inode or deleting it.
2746  */
2747 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2748 {
2749         struct super_block *sb = inode->i_sb;
2750         struct ext4_sb_info *sbi = EXT4_SB(sb);
2751         struct ext4_iloc iloc;
2752         int err = 0, rc;
2753         bool dirty = false;
2754 
2755         if (!sbi->s_journal || is_bad_inode(inode))
2756                 return 0;
2757 
2758         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2759                      !inode_is_locked(inode));
2760         /*
2761          * Exit early if inode already is on orphan list. This is a big speedup
2762          * since we don't have to contend on the global s_orphan_lock.
2763          */
2764         if (!list_empty(&EXT4_I(inode)->i_orphan))
2765                 return 0;
2766 
2767         /*
2768          * Orphan handling is only valid for files with data blocks
2769          * being truncated, or files being unlinked. Note that we either
2770          * hold i_mutex, or the inode can not be referenced from outside,
2771          * so i_nlink should not be bumped due to race
2772          */
2773         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2774                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2775 
2776         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2777         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2778         if (err)
2779                 goto out;
2780 
2781         err = ext4_reserve_inode_write(handle, inode, &iloc);
2782         if (err)
2783                 goto out;
2784 
2785         mutex_lock(&sbi->s_orphan_lock);
2786         /*
2787          * Due to previous errors inode may be already a part of on-disk
2788          * orphan list. If so skip on-disk list modification.
2789          */
2790         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2791             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2792                 /* Insert this inode at the head of the on-disk orphan list */
2793                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2794                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2795                 dirty = true;
2796         }
2797         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2798         mutex_unlock(&sbi->s_orphan_lock);
2799 
2800         if (dirty) {
2801                 err = ext4_handle_dirty_super(handle, sb);
2802                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2803                 if (!err)
2804                         err = rc;
2805                 if (err) {
2806                         /*
2807                          * We have to remove inode from in-memory list if
2808                          * addition to on disk orphan list failed. Stray orphan
2809                          * list entries can cause panics at unmount time.
2810                          */
2811                         mutex_lock(&sbi->s_orphan_lock);
2812                         list_del_init(&EXT4_I(inode)->i_orphan);
2813                         mutex_unlock(&sbi->s_orphan_lock);
2814                 }
2815         } else
2816                 brelse(iloc.bh);
2817 
2818         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2819         jbd_debug(4, "orphan inode %lu will point to %d\n",
2820                         inode->i_ino, NEXT_ORPHAN(inode));
2821 out:
2822         ext4_std_error(sb, err);
2823         return err;
2824 }
2825 
2826 /*
2827  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2828  * of such inodes stored on disk, because it is finally being cleaned up.
2829  */
2830 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2831 {
2832         struct list_head *prev;
2833         struct ext4_inode_info *ei = EXT4_I(inode);
2834         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2835         __u32 ino_next;
2836         struct ext4_iloc iloc;
2837         int err = 0;
2838 
2839         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2840                 return 0;
2841 
2842         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2843                      !inode_is_locked(inode));
2844         /* Do this quick check before taking global s_orphan_lock. */
2845         if (list_empty(&ei->i_orphan))
2846                 return 0;
2847 
2848         if (handle) {
2849                 /* Grab inode buffer early before taking global s_orphan_lock */
2850                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2851         }
2852 
2853         mutex_lock(&sbi->s_orphan_lock);
2854         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2855 
2856         prev = ei->i_orphan.prev;
2857         list_del_init(&ei->i_orphan);
2858 
2859         /* If we're on an error path, we may not have a valid
2860          * transaction handle with which to update the orphan list on
2861          * disk, but we still need to remove the inode from the linked
2862          * list in memory. */
2863         if (!handle || err) {
2864                 mutex_unlock(&sbi->s_orphan_lock);
2865                 goto out_err;
2866         }
2867 
2868         ino_next = NEXT_ORPHAN(inode);
2869         if (prev == &sbi->s_orphan) {
2870                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2871                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2872                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2873                 if (err) {
2874                         mutex_unlock(&sbi->s_orphan_lock);
2875                         goto out_brelse;
2876                 }
2877                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2878                 mutex_unlock(&sbi->s_orphan_lock);
2879                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2880         } else {
2881                 struct ext4_iloc iloc2;
2882                 struct inode *i_prev =
2883                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2884 
2885                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2886                           i_prev->i_ino, ino_next);
2887                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2888                 if (err) {
2889                         mutex_unlock(&sbi->s_orphan_lock);
2890                         goto out_brelse;
2891                 }
2892                 NEXT_ORPHAN(i_prev) = ino_next;
2893                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2894                 mutex_unlock(&sbi->s_orphan_lock);
2895         }
2896         if (err)
2897                 goto out_brelse;
2898         NEXT_ORPHAN(inode) = 0;
2899         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2900 out_err:
2901         ext4_std_error(inode->i_sb, err);
2902         return err;
2903 
2904 out_brelse:
2905         brelse(iloc.bh);
2906         goto out_err;
2907 }
2908 
2909 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2910 {
2911         int retval;
2912         struct inode *inode;
2913         struct buffer_head *bh;
2914         struct ext4_dir_entry_2 *de;
2915         handle_t *handle = NULL;
2916 
2917         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2918                 return -EIO;
2919 
2920         /* Initialize quotas before so that eventual writes go in
2921          * separate transaction */
2922         retval = dquot_initialize(dir);
2923         if (retval)
2924                 return retval;
2925         retval = dquot_initialize(d_inode(dentry));
2926         if (retval)
2927                 return retval;
2928 
2929         retval = -ENOENT;
2930         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2931         if (IS_ERR(bh))
2932                 return PTR_ERR(bh);
2933         if (!bh)
2934                 goto end_rmdir;
2935 
2936         inode = d_inode(dentry);
2937 
2938         retval = -EFSCORRUPTED;
2939         if (le32_to_cpu(de->inode) != inode->i_ino)
2940                 goto end_rmdir;
2941 
2942         retval = -ENOTEMPTY;
2943         if (!ext4_empty_dir(inode))
2944                 goto end_rmdir;
2945 
2946         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2947                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2948         if (IS_ERR(handle)) {
2949                 retval = PTR_ERR(handle);
2950                 handle = NULL;
2951                 goto end_rmdir;
2952         }
2953 
2954         if (IS_DIRSYNC(dir))
2955                 ext4_handle_sync(handle);
2956 
2957         retval = ext4_delete_entry(handle, dir, de, bh);
2958         if (retval)
2959                 goto end_rmdir;
2960         if (!EXT4_DIR_LINK_EMPTY(inode))
2961                 ext4_warning_inode(inode,
2962                              "empty directory '%.*s' has too many links (%u)",
2963                              dentry->d_name.len, dentry->d_name.name,
2964                              inode->i_nlink);
2965         inode_inc_iversion(inode);
2966         clear_nlink(inode);
2967         /* There's no need to set i_disksize: the fact that i_nlink is
2968          * zero will ensure that the right thing happens during any
2969          * recovery. */
2970         inode->i_size = 0;
2971         ext4_orphan_add(handle, inode);
2972         inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2973         ext4_mark_inode_dirty(handle, inode);
2974         ext4_dec_count(handle, dir);
2975         ext4_update_dx_flag(dir);
2976         ext4_mark_inode_dirty(handle, dir);
2977 
2978 end_rmdir:
2979         brelse(bh);
2980         if (handle)
2981                 ext4_journal_stop(handle);
2982         return retval;
2983 }
2984 
2985 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2986 {
2987         int retval;
2988         struct inode *inode;
2989         struct buffer_head *bh;
2990         struct ext4_dir_entry_2 *de;
2991         handle_t *handle = NULL;
2992 
2993         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2994                 return -EIO;
2995 
2996         trace_ext4_unlink_enter(dir, dentry);
2997         /* Initialize quotas before so that eventual writes go
2998          * in separate transaction */
2999         retval = dquot_initialize(dir);
3000         if (retval)
3001                 return retval;
3002         retval = dquot_initialize(d_inode(dentry));
3003         if (retval)
3004                 return retval;
3005 
3006         retval = -ENOENT;
3007         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3008         if (IS_ERR(bh))
3009                 return PTR_ERR(bh);
3010         if (!bh)
3011                 goto end_unlink;
3012 
3013         inode = d_inode(dentry);
3014 
3015         retval = -EFSCORRUPTED;
3016         if (le32_to_cpu(de->inode) != inode->i_ino)
3017                 goto end_unlink;
3018 
3019         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3020                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3021         if (IS_ERR(handle)) {
3022                 retval = PTR_ERR(handle);
3023                 handle = NULL;
3024                 goto end_unlink;
3025         }
3026 
3027         if (IS_DIRSYNC(dir))
3028                 ext4_handle_sync(handle);
3029 
3030         if (inode->i_nlink == 0) {
3031                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3032                                    dentry->d_name.len, dentry->d_name.name);
3033                 set_nlink(inode, 1);
3034         }
3035         retval = ext4_delete_entry(handle, dir, de, bh);
3036         if (retval)
3037                 goto end_unlink;
3038         dir->i_ctime = dir->i_mtime = current_time(dir);
3039         ext4_update_dx_flag(dir);
3040         ext4_mark_inode_dirty(handle, dir);
3041         drop_nlink(inode);
3042         if (!inode->i_nlink)
3043                 ext4_orphan_add(handle, inode);
3044         inode->i_ctime = current_time(inode);
3045         ext4_mark_inode_dirty(handle, inode);
3046 
3047 end_unlink:
3048         brelse(bh);
3049         if (handle)
3050                 ext4_journal_stop(handle);
3051         trace_ext4_unlink_exit(dentry, retval);
3052         return retval;
3053 }
3054 
3055 static int ext4_symlink(struct inode *dir,
3056                         struct dentry *dentry, const char *symname)
3057 {
3058         handle_t *handle;
3059         struct inode *inode;
3060         int err, len = strlen(symname);
3061         int credits;
3062         struct fscrypt_str disk_link;
3063 
3064         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3065                 return -EIO;
3066 
3067         err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
3068                                       &disk_link);
3069         if (err)
3070                 return err;
3071 
3072         err = dquot_initialize(dir);
3073         if (err)
3074                 return err;
3075 
3076         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3077                 /*
3078                  * For non-fast symlinks, we just allocate inode and put it on
3079                  * orphan list in the first transaction => we need bitmap,
3080                  * group descriptor, sb, inode block, quota blocks, and
3081                  * possibly selinux xattr blocks.
3082                  */
3083                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3084                           EXT4_XATTR_TRANS_BLOCKS;
3085         } else {
3086                 /*
3087                  * Fast symlink. We have to add entry to directory
3088                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3089                  * allocate new inode (bitmap, group descriptor, inode block,
3090                  * quota blocks, sb is already counted in previous macros).
3091                  */
3092                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3093                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3094         }
3095 
3096         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3097                                             &dentry->d_name, 0, NULL,
3098                                             EXT4_HT_DIR, credits);
3099         handle = ext4_journal_current_handle();
3100         if (IS_ERR(inode)) {
3101                 if (handle)
3102                         ext4_journal_stop(handle);
3103                 return PTR_ERR(inode);
3104         }
3105 
3106         if (IS_ENCRYPTED(inode)) {
3107                 err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
3108                 if (err)
3109                         goto err_drop_inode;
3110                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3111         }
3112 
3113         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3114                 if (!IS_ENCRYPTED(inode))
3115                         inode->i_op = &ext4_symlink_inode_operations;
3116                 inode_nohighmem(inode);
3117                 ext4_set_aops(inode);
3118                 /*
3119                  * We cannot call page_symlink() with transaction started
3120                  * because it calls into ext4_write_begin() which can wait
3121                  * for transaction commit if we are running out of space
3122                  * and thus we deadlock. So we have to stop transaction now
3123                  * and restart it when symlink contents is written.
3124                  * 
3125                  * To keep fs consistent in case of crash, we have to put inode
3126                  * to orphan list in the mean time.
3127                  */
3128                 drop_nlink(inode);
3129                 err = ext4_orphan_add(handle, inode);
3130                 ext4_journal_stop(handle);
3131                 handle = NULL;
3132                 if (err)
3133                         goto err_drop_inode;
3134                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3135                 if (err)
3136                         goto err_drop_inode;
3137                 /*
3138                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3139                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3140                  */
3141                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3142                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3143                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3144                 if (IS_ERR(handle)) {
3145                         err = PTR_ERR(handle);
3146                         handle = NULL;
3147                         goto err_drop_inode;
3148                 }
3149                 set_nlink(inode, 1);
3150                 err = ext4_orphan_del(handle, inode);
3151                 if (err)
3152                         goto err_drop_inode;
3153         } else {
3154                 /* clear the extent format for fast symlink */
3155                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3156                 if (!IS_ENCRYPTED(inode)) {
3157                         inode->i_op = &ext4_fast_symlink_inode_operations;
3158                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3159                 }
3160                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3161                        disk_link.len);
3162                 inode->i_size = disk_link.len - 1;
3163         }
3164         EXT4_I(inode)->i_disksize = inode->i_size;
3165         err = ext4_add_nondir(handle, dentry, inode);
3166         if (!err && IS_DIRSYNC(dir))
3167                 ext4_handle_sync(handle);
3168 
3169         if (handle)
3170                 ext4_journal_stop(handle);
3171         goto out_free_encrypted_link;
3172 
3173 err_drop_inode:
3174         if (handle)
3175                 ext4_journal_stop(handle);
3176         clear_nlink(inode);
3177         unlock_new_inode(inode);
3178         iput(inode);
3179 out_free_encrypted_link:
3180         if (disk_link.name != (unsigned char *)symname)
3181                 kfree(disk_link.name);
3182         return err;
3183 }
3184 
3185 static int ext4_link(struct dentry *old_dentry,
3186                      struct inode *dir, struct dentry *dentry)
3187 {
3188         handle_t *handle;
3189         struct inode *inode = d_inode(old_dentry);
3190         int err, retries = 0;
3191 
3192         if (inode->i_nlink >= EXT4_LINK_MAX)
3193                 return -EMLINK;
3194 
3195         err = fscrypt_prepare_link(old_dentry, dir, dentry);
3196         if (err)
3197                 return err;
3198 
3199         if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3200             (!projid_eq(EXT4_I(dir)->i_projid,
3201                         EXT4_I(old_dentry->d_inode)->i_projid)))
3202                 return -EXDEV;
3203 
3204         err = dquot_initialize(dir);
3205         if (err)
3206                 return err;
3207 
3208 retry:
3209         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3210                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3211                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3212         if (IS_ERR(handle))
3213                 return PTR_ERR(handle);
3214 
3215         if (IS_DIRSYNC(dir))
3216                 ext4_handle_sync(handle);
3217 
3218         inode->i_ctime = current_time(inode);
3219         ext4_inc_count(handle, inode);
3220         ihold(inode);
3221 
3222         err = ext4_add_entry(handle, dentry, inode);
3223         if (!err) {
3224                 ext4_mark_inode_dirty(handle, inode);
3225                 /* this can happen only for tmpfile being
3226                  * linked the first time
3227                  */
3228                 if (inode->i_nlink == 1)
3229                         ext4_orphan_del(handle, inode);
3230                 d_instantiate(dentry, inode);
3231         } else {
3232                 drop_nlink(inode);
3233                 iput(inode);
3234         }
3235         ext4_journal_stop(handle);
3236         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3237                 goto retry;
3238         return err;
3239 }
3240 
3241 
3242 /*
3243  * Try to find buffer head where contains the parent block.
3244  * It should be the inode block if it is inlined or the 1st block
3245  * if it is a normal dir.
3246  */
3247 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3248                                         struct inode *inode,
3249                                         int *retval,
3250                                         struct ext4_dir_entry_2 **parent_de,
3251                                         int *inlined)
3252 {
3253         struct buffer_head *bh;
3254 
3255         if (!ext4_has_inline_data(inode)) {
3256                 bh = ext4_read_dirblock(inode, 0, EITHER);
3257                 if (IS_ERR(bh)) {
3258                         *retval = PTR_ERR(bh);
3259                         return NULL;
3260                 }
3261                 *parent_de = ext4_next_entry(
3262                                         (struct ext4_dir_entry_2 *)bh->b_data,
3263                                         inode->i_sb->s_blocksize);
3264                 return bh;
3265         }
3266 
3267         *inlined = 1;
3268         return ext4_get_first_inline_block(inode, parent_de, retval);
3269 }
3270 
3271 struct ext4_renament {
3272         struct inode *dir;
3273         struct dentry *dentry;
3274         struct inode *inode;
3275         bool is_dir;
3276         int dir_nlink_delta;
3277 
3278         /* entry for "dentry" */
3279         struct buffer_head *bh;
3280         struct ext4_dir_entry_2 *de;
3281         int inlined;
3282 
3283         /* entry for ".." in inode if it's a directory */
3284         struct buffer_head *dir_bh;
3285         struct ext4_dir_entry_2 *parent_de;
3286         int dir_inlined;
3287 };
3288 
3289 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3290 {
3291         int retval;
3292 
3293         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3294                                               &retval, &ent->parent_de,
3295                                               &ent->dir_inlined);
3296         if (!ent->dir_bh)
3297                 return retval;
3298         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3299                 return -EFSCORRUPTED;
3300         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3301         return ext4_journal_get_write_access(handle, ent->dir_bh);
3302 }
3303 
3304 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3305                                   unsigned dir_ino)
3306 {
3307         int retval;
3308 
3309         ent->parent_de->inode = cpu_to_le32(dir_ino);
3310         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3311         if (!ent->dir_inlined) {
3312                 if (is_dx(ent->inode)) {
3313                         retval = ext4_handle_dirty_dx_node(handle,
3314                                                            ent->inode,
3315                                                            ent->dir_bh);
3316                 } else {
3317                         retval = ext4_handle_dirty_dirent_node(handle,
3318                                                                ent->inode,
3319                                                                ent->dir_bh);
3320                 }
3321         } else {
3322                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3323         }
3324         if (retval) {
3325                 ext4_std_error(ent->dir->i_sb, retval);
3326                 return retval;
3327         }
3328         return 0;
3329 }
3330 
3331 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3332                        unsigned ino, unsigned file_type)
3333 {
3334         int retval;
3335 
3336         BUFFER_TRACE(ent->bh, "get write access");
3337         retval = ext4_journal_get_write_access(handle, ent->bh);
3338         if (retval)
3339                 return retval;
3340         ent->de->inode = cpu_to_le32(ino);
3341         if (ext4_has_feature_filetype(ent->dir->i_sb))
3342                 ent->de->file_type = file_type;
3343         inode_inc_iversion(ent->dir);
3344         ent->dir->i_ctime = ent->dir->i_mtime =
3345                 current_time(ent->dir);
3346         ext4_mark_inode_dirty(handle, ent->dir);
3347         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3348         if (!ent->inlined) {
3349                 retval = ext4_handle_dirty_dirent_node(handle,
3350                                                        ent->dir, ent->bh);
3351                 if (unlikely(retval)) {
3352                         ext4_std_error(ent->dir->i_sb, retval);
3353                         return retval;
3354                 }
3355         }
3356         brelse(ent->bh);
3357         ent->bh = NULL;
3358 
3359         return 0;
3360 }
3361 
3362 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3363                                   const struct qstr *d_name)
3364 {
3365         int retval = -ENOENT;
3366         struct buffer_head *bh;
3367         struct ext4_dir_entry_2 *de;
3368 
3369         bh = ext4_find_entry(dir, d_name, &de, NULL);
3370         if (IS_ERR(bh))
3371                 return PTR_ERR(bh);
3372         if (bh) {
3373                 retval = ext4_delete_entry(handle, dir, de, bh);
3374                 brelse(bh);
3375         }
3376         return retval;
3377 }
3378 
3379 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3380                                int force_reread)
3381 {
3382         int retval;
3383         /*
3384          * ent->de could have moved from under us during htree split, so make
3385          * sure that we are deleting the right entry.  We might also be pointing
3386          * to a stale entry in the unused part of ent->bh so just checking inum
3387          * and the name isn't enough.
3388          */
3389         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3390             ent->de->name_len != ent->dentry->d_name.len ||
3391             strncmp(ent->de->name, ent->dentry->d_name.name,
3392                     ent->de->name_len) ||
3393             force_reread) {
3394                 retval = ext4_find_delete_entry(handle, ent->dir,
3395                                                 &ent->dentry->d_name);
3396         } else {
3397                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3398                 if (retval == -ENOENT) {
3399                         retval = ext4_find_delete_entry(handle, ent->dir,
3400                                                         &ent->dentry->d_name);
3401                 }
3402         }
3403 
3404         if (retval) {
3405                 ext4_warning_inode(ent->dir,
3406                                    "Deleting old file: nlink %d, error=%d",
3407                                    ent->dir->i_nlink, retval);
3408         }
3409 }
3410 
3411 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3412 {
3413         if (ent->dir_nlink_delta) {
3414                 if (ent->dir_nlink_delta == -1)
3415                         ext4_dec_count(handle, ent->dir);
3416                 else
3417                         ext4_inc_count(handle, ent->dir);
3418                 ext4_mark_inode_dirty(handle, ent->dir);
3419         }
3420 }
3421 
3422 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3423                                               int credits, handle_t **h)
3424 {
3425         struct inode *wh;
3426         handle_t *handle;
3427         int retries = 0;
3428 
3429         /*
3430          * for inode block, sb block, group summaries,
3431          * and inode bitmap
3432          */
3433         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3434                     EXT4_XATTR_TRANS_BLOCKS + 4);
3435 retry:
3436         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3437                                          &ent->dentry->d_name, 0, NULL,
3438                                          EXT4_HT_DIR, credits);
3439 
3440         handle = ext4_journal_current_handle();
3441         if (IS_ERR(wh)) {
3442                 if (handle)
3443                         ext4_journal_stop(handle);
3444                 if (PTR_ERR(wh) == -ENOSPC &&
3445                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3446                         goto retry;
3447         } else {
3448                 *h = handle;
3449                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3450                 wh->i_op = &ext4_special_inode_operations;
3451         }
3452         return wh;
3453 }
3454 
3455 /*
3456  * Anybody can rename anything with this: the permission checks are left to the
3457  * higher-level routines.
3458  *
3459  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3460  * while new_{dentry,inode) refers to the destination dentry/inode
3461  * This comes from rename(const char *oldpath, const char *newpath)
3462  */
3463 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3464                        struct inode *new_dir, struct dentry *new_dentry,
3465                        unsigned int flags)
3466 {
3467         handle_t *handle = NULL;
3468         struct ext4_renament old = {
3469                 .dir = old_dir,
3470                 .dentry = old_dentry,
3471                 .inode = d_inode(old_dentry),
3472         };
3473         struct ext4_renament new = {
3474                 .dir = new_dir,
3475                 .dentry = new_dentry,
3476                 .inode = d_inode(new_dentry),
3477         };
3478         int force_reread;
3479         int retval;
3480         struct inode *whiteout = NULL;
3481         int credits;
3482         u8 old_file_type;
3483 
3484         if (new.inode && new.inode->i_nlink == 0) {
3485                 EXT4_ERROR_INODE(new.inode,
3486                                  "target of rename is already freed");
3487                 return -EFSCORRUPTED;
3488         }
3489 
3490         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3491             (!projid_eq(EXT4_I(new_dir)->i_projid,
3492                         EXT4_I(old_dentry->d_inode)->i_projid)))
3493                 return -EXDEV;
3494 
3495         retval = dquot_initialize(old.dir);
3496         if (retval)
3497                 return retval;
3498         retval = dquot_initialize(new.dir);
3499         if (retval)
3500                 return retval;
3501 
3502         /* Initialize quotas before so that eventual writes go
3503          * in separate transaction */
3504         if (new.inode) {
3505                 retval = dquot_initialize(new.inode);
3506                 if (retval)
3507                         return retval;
3508         }
3509 
3510         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3511         if (IS_ERR(old.bh))
3512                 return PTR_ERR(old.bh);
3513         /*
3514          *  Check for inode number is _not_ due to possible IO errors.
3515          *  We might rmdir the source, keep it as pwd of some process
3516          *  and merrily kill the link to whatever was created under the
3517          *  same name. Goodbye sticky bit ;-<
3518          */
3519         retval = -ENOENT;
3520         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3521                 goto end_rename;
3522 
3523         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3524                                  &new.de, &new.inlined);
3525         if (IS_ERR(new.bh)) {
3526                 retval = PTR_ERR(new.bh);
3527                 new.bh = NULL;
3528                 goto end_rename;
3529         }
3530         if (new.bh) {
3531                 if (!new.inode) {
3532                         brelse(new.bh);
3533                         new.bh = NULL;
3534                 }
3535         }
3536         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3537                 ext4_alloc_da_blocks(old.inode);
3538 
3539         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3540                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3541         if (!(flags & RENAME_WHITEOUT)) {
3542                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3543                 if (IS_ERR(handle)) {
3544                         retval = PTR_ERR(handle);
3545                         handle = NULL;
3546                         goto end_rename;
3547                 }
3548         } else {
3549                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3550                 if (IS_ERR(whiteout)) {
3551                         retval = PTR_ERR(whiteout);
3552                         whiteout = NULL;
3553                         goto end_rename;
3554                 }
3555         }
3556 
3557         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3558                 ext4_handle_sync(handle);
3559 
3560         if (S_ISDIR(old.inode->i_mode)) {
3561                 if (new.inode) {
3562                         retval = -ENOTEMPTY;
3563                         if (!ext4_empty_dir(new.inode))
3564                                 goto end_rename;
3565                 } else {
3566                         retval = -EMLINK;
3567                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3568                                 goto end_rename;
3569                 }
3570                 retval = ext4_rename_dir_prepare(handle, &old);
3571                 if (retval)
3572                         goto end_rename;
3573         }
3574         /*
3575          * If we're renaming a file within an inline_data dir and adding or
3576          * setting the new dirent causes a conversion from inline_data to
3577          * extents/blockmap, we need to force the dirent delete code to
3578          * re-read the directory, or else we end up trying to delete a dirent
3579          * from what is now the extent tree root (or a block map).
3580          */
3581         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3582                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3583 
3584         old_file_type = old.de->file_type;
3585         if (whiteout) {
3586                 /*
3587                  * Do this before adding a new entry, so the old entry is sure
3588                  * to be still pointing to the valid old entry.
3589                  */
3590                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3591                                      EXT4_FT_CHRDEV);
3592                 if (retval)
3593                         goto end_rename;
3594                 ext4_mark_inode_dirty(handle, whiteout);
3595         }
3596         if (!new.bh) {
3597                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3598                 if (retval)
3599                         goto end_rename;
3600         } else {
3601                 retval = ext4_setent(handle, &new,
3602                                      old.inode->i_ino, old_file_type);
3603                 if (retval)
3604                         goto end_rename;
3605         }
3606         if (force_reread)
3607                 force_reread = !ext4_test_inode_flag(new.dir,
3608                                                      EXT4_INODE_INLINE_DATA);
3609 
3610         /*
3611          * Like most other Unix systems, set the ctime for inodes on a
3612          * rename.
3613          */
3614         old.inode->i_ctime = current_time(old.inode);
3615         ext4_mark_inode_dirty(handle, old.inode);
3616 
3617         if (!whiteout) {
3618                 /*
3619                  * ok, that's it
3620                  */
3621                 ext4_rename_delete(handle, &old, force_reread);
3622         }
3623 
3624         if (new.inode) {
3625                 ext4_dec_count(handle, new.inode);
3626                 new.inode->i_ctime = current_time(new.inode);
3627         }
3628         old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
3629         ext4_update_dx_flag(old.dir);
3630         if (old.dir_bh) {
3631                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3632                 if (retval)
3633                         goto end_rename;
3634 
3635                 ext4_dec_count(handle, old.dir);
3636                 if (new.inode) {
3637                         /* checked ext4_empty_dir above, can't have another
3638                          * parent, ext4_dec_count() won't work for many-linked
3639                          * dirs */
3640                         clear_nlink(new.inode);
3641                 } else {
3642                         ext4_inc_count(handle, new.dir);
3643                         ext4_update_dx_flag(new.dir);
3644                         ext4_mark_inode_dirty(handle, new.dir);
3645                 }
3646         }
3647         ext4_mark_inode_dirty(handle, old.dir);
3648         if (new.inode) {
3649                 ext4_mark_inode_dirty(handle, new.inode);
3650                 if (!new.inode->i_nlink)
3651                         ext4_orphan_add(handle, new.inode);
3652         }
3653         retval = 0;
3654 
3655 end_rename:
3656         brelse(old.dir_bh);
3657         brelse(old.bh);
3658         brelse(new.bh);
3659         if (whiteout) {
3660                 if (retval)
3661                         drop_nlink(whiteout);
3662                 unlock_new_inode(whiteout);
3663                 iput(whiteout);
3664         }
3665         if (handle)
3666                 ext4_journal_stop(handle);
3667         return retval;
3668 }
3669 
3670 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3671                              struct inode *new_dir, struct dentry *new_dentry)
3672 {
3673         handle_t *handle = NULL;
3674         struct ext4_renament old = {
3675                 .dir = old_dir,
3676                 .dentry = old_dentry,
3677                 .inode = d_inode(old_dentry),
3678         };
3679         struct ext4_renament new = {
3680                 .dir = new_dir,
3681                 .dentry = new_dentry,
3682                 .inode = d_inode(new_dentry),
3683         };
3684         u8 new_file_type;
3685         int retval;
3686         struct timespec64 ctime;
3687 
3688         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
3689              !projid_eq(EXT4_I(new_dir)->i_projid,
3690                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
3691             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
3692              !projid_eq(EXT4_I(old_dir)->i_projid,
3693                         EXT4_I(new_dentry->d_inode)->i_projid)))
3694                 return -EXDEV;
3695 
3696         retval = dquot_initialize(old.dir);
3697         if (retval)
3698                 return retval;
3699         retval = dquot_initialize(new.dir);
3700         if (retval)
3701                 return retval;
3702 
3703         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3704                                  &old.de, &old.inlined);
3705         if (IS_ERR(old.bh))
3706                 return PTR_ERR(old.bh);
3707         /*
3708          *  Check for inode number is _not_ due to possible IO errors.
3709          *  We might rmdir the source, keep it as pwd of some process
3710          *  and merrily kill the link to whatever was created under the
3711          *  same name. Goodbye sticky bit ;-<
3712          */
3713         retval = -ENOENT;
3714         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3715                 goto end_rename;
3716 
3717         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3718                                  &new.de, &new.inlined);
3719         if (IS_ERR(new.bh)) {
3720                 retval = PTR_ERR(new.bh);
3721                 new.bh = NULL;
3722                 goto end_rename;
3723         }
3724 
3725         /* RENAME_EXCHANGE case: old *and* new must both exist */
3726         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3727                 goto end_rename;
3728 
3729         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3730                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3731                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3732         if (IS_ERR(handle)) {
3733                 retval = PTR_ERR(handle);
3734                 handle = NULL;
3735                 goto end_rename;
3736         }
3737 
3738         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3739                 ext4_handle_sync(handle);
3740 
3741         if (S_ISDIR(old.inode->i_mode)) {
3742                 old.is_dir = true;
3743                 retval = ext4_rename_dir_prepare(handle, &old);
3744                 if (retval)
3745                         goto end_rename;
3746         }
3747         if (S_ISDIR(new.inode->i_mode)) {
3748                 new.is_dir = true;
3749                 retval = ext4_rename_dir_prepare(handle, &new);
3750                 if (retval)
3751                         goto end_rename;
3752         }
3753 
3754         /*
3755          * Other than the special case of overwriting a directory, parents'
3756          * nlink only needs to be modified if this is a cross directory rename.
3757          */
3758         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3759                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3760                 new.dir_nlink_delta = -old.dir_nlink_delta;
3761                 retval = -EMLINK;
3762                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3763                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3764                         goto end_rename;
3765         }
3766 
3767         new_file_type = new.de->file_type;
3768         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3769         if (retval)
3770                 goto end_rename;
3771 
3772         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3773         if (retval)
3774                 goto end_rename;
3775 
3776         /*
3777          * Like most other Unix systems, set the ctime for inodes on a
3778          * rename.
3779          */
3780         ctime = current_time(old.inode);
3781         old.inode->i_ctime = ctime;
3782         new.inode->i_ctime = ctime;
3783         ext4_mark_inode_dirty(handle, old.inode);
3784         ext4_mark_inode_dirty(handle, new.inode);
3785 
3786         if (old.dir_bh) {
3787                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3788                 if (retval)
3789                         goto end_rename;
3790         }
3791         if (new.dir_bh) {
3792                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3793                 if (retval)
3794                         goto end_rename;
3795         }
3796         ext4_update_dir_count(handle, &old);
3797         ext4_update_dir_count(handle, &new);
3798         retval = 0;
3799 
3800 end_rename:
3801         brelse(old.dir_bh);
3802         brelse(new.dir_bh);
3803         brelse(old.bh);
3804         brelse(new.bh);
3805         if (handle)
3806                 ext4_journal_stop(handle);
3807         return retval;
3808 }
3809 
3810 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3811                         struct inode *new_dir, struct dentry *new_dentry,
3812                         unsigned int flags)
3813 {
3814         int err;
3815 
3816         if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
3817                 return -EIO;
3818 
3819         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3820                 return -EINVAL;
3821 
3822         err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
3823                                      flags);
3824         if (err)
3825                 return err;
3826 
3827         if (flags & RENAME_EXCHANGE) {
3828                 return ext4_cross_rename(old_dir, old_dentry,
3829                                          new_dir, new_dentry);
3830         }
3831 
3832         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3833 }
3834 
3835 /*
3836  * directories can handle most operations...
3837  */
3838 const struct inode_operations ext4_dir_inode_operations = {
3839         .create         = ext4_create,
3840         .lookup         = ext4_lookup,
3841         .link           = ext4_link,
3842         .unlink         = ext4_unlink,
3843         .symlink        = ext4_symlink,
3844         .mkdir          = ext4_mkdir,
3845         .rmdir          = ext4_rmdir,
3846         .mknod          = ext4_mknod,
3847         .tmpfile        = ext4_tmpfile,
3848         .rename         = ext4_rename2,
3849         .setattr        = ext4_setattr,
3850         .getattr        = ext4_getattr,
3851         .listxattr      = ext4_listxattr,
3852         .get_acl        = ext4_get_acl,
3853         .set_acl        = ext4_set_acl,
3854         .fiemap         = ext4_fiemap,
3855 };
3856 
3857 const struct inode_operations ext4_special_inode_operations = {
3858         .setattr        = ext4_setattr,
3859         .getattr        = ext4_getattr,
3860         .listxattr      = ext4_listxattr,
3861         .get_acl        = ext4_get_acl,
3862         .set_acl        = ext4_set_acl,
3863 };
3864 

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