fs/ext4/namei.c

   1 /*
   2  *  linux/fs/ext4/namei.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/namei.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  *  Directory entry file type support and forward compatibility hooks
  18  *      for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
  19  *  Hash Tree Directory indexing (c)
  20  *      Daniel Phillips, 2001
  21  *  Hash Tree Directory indexing porting
  22  *      Christopher Li, 2002
  23  *  Hash Tree Directory indexing cleanup
  24  *      Theodore Ts'o, 2002
  25  */
  26
  27 #include <linux/fs.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/time.h>
  30 #include <linux/fcntl.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/quotaops.h>
  34 #include <linux/buffer_head.h>
  35 #include <linux/bio.h>
  36 #include "ext4.h"
  37 #include "ext4_jbd2.h"
  38
  39 #include "xattr.h"
  40 #include "acl.h"
  41
  42 #include <trace/events/ext4.h>
  43 /*
  44  * define how far ahead to read directories while searching them.
  45  */
  46 #define NAMEI_RA_CHUNKS  2
  47 #define NAMEI_RA_BLOCKS  4
  48 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
  49
  50 static struct buffer_head *ext4_append(handle_t *handle,
  51                                         struct inode *inode,
  52                                         ext4_lblk_t *block)
  53 {
  54         struct buffer_head *bh;
  55         int err;
  56
  57         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
  58                      ((inode->i_size >> 10) >=
  59                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
  60                 return ERR_PTR(-ENOSPC);
  61
  62         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
  63
  64         bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
  65         if (IS_ERR(bh))
  66                 return bh;
  67         inode->i_size += inode->i_sb->s_blocksize;
  68         EXT4_I(inode)->i_disksize = inode->i_size;
  69         BUFFER_TRACE(bh, "get_write_access");
  70         err = ext4_journal_get_write_access(handle, bh);
  71         if (err) {
  72                 brelse(bh);
  73                 ext4_std_error(inode->i_sb, err);
  74                 return ERR_PTR(err);
  75         }
  76         return bh;
  77 }
  78
  79 static int ext4_dx_csum_verify(struct inode *inode,
  80                                struct ext4_dir_entry *dirent);
  81
  82 typedef enum {
  83         EITHER, INDEX, DIRENT
  84 } dirblock_type_t;
  85
  86 #define ext4_read_dirblock(inode, block, type) \
  87         __ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
  88
  89 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
  90                                                 ext4_lblk_t block,
  91                                                 dirblock_type_t type,
  92                                                 const char *func,
  93                                                 unsigned int line)
  94 {
  95         struct buffer_head *bh;
  96         struct ext4_dir_entry *dirent;
  97         int is_dx_block = 0;
  98
  99         bh = ext4_bread(NULL, inode, block, 0);
 100         if (IS_ERR(bh)) {
 101                 __ext4_warning(inode->i_sb, func, line,
 102                                "inode #%lu: lblock %lu: comm %s: "
 103                                "error %ld reading directory block",
 104                                inode->i_ino, (unsigned long)block,
 105                                current->comm, PTR_ERR(bh));
 106
 107                 return bh;
 108         }
 109         if (!bh) {
 110                 ext4_error_inode(inode, func, line, block,
 111                                  "Directory hole found");
 112                 return ERR_PTR(-EFSCORRUPTED);
 113         }
 114         dirent = (struct ext4_dir_entry *) bh->b_data;
 115         /* Determine whether or not we have an index block */
 116         if (is_dx(inode)) {
 117                 if (block == 0)
 118                         is_dx_block = 1;
 119                 else if (ext4_rec_len_from_disk(dirent->rec_len,
 120                                                 inode->i_sb->s_blocksize) ==
 121                          inode->i_sb->s_blocksize)
 122                         is_dx_block = 1;
 123         }
 124         if (!is_dx_block && type == INDEX) {
 125                 ext4_error_inode(inode, func, line, block,
 126                        "directory leaf block found instead of index block");
 127                 return ERR_PTR(-EFSCORRUPTED);
 128         }
 129         if (!ext4_has_metadata_csum(inode->i_sb) ||
 130             buffer_verified(bh))
 131                 return bh;
 132
 133         /*
 134          * An empty leaf block can get mistaken for a index block; for
 135          * this reason, we can only check the index checksum when the
 136          * caller is sure it should be an index block.
 137          */
 138         if (is_dx_block && type == INDEX) {
 139                 if (ext4_dx_csum_verify(inode, dirent))
 140                         set_buffer_verified(bh);
 141                 else {
 142                         ext4_error_inode(inode, func, line, block,
 143                                          "Directory index failed checksum");
 144                         brelse(bh);
 145                         return ERR_PTR(-EFSBADCRC);
 146                 }
 147         }
 148         if (!is_dx_block) {
 149                 if (ext4_dirent_csum_verify(inode, dirent))
 150                         set_buffer_verified(bh);
 151                 else {
 152                         ext4_error_inode(inode, func, line, block,
 153                                          "Directory block failed checksum");
 154                         brelse(bh);
 155                         return ERR_PTR(-EFSBADCRC);
 156                 }
 157         }
 158         return bh;
 159 }
 160
 161 #ifndef assert
 162 #define assert(test) J_ASSERT(test)
 163 #endif
 164
 165 #ifdef DX_DEBUG
 166 #define dxtrace(command) command
 167 #else
 168 #define dxtrace(command)
 169 #endif
 170
 171 struct fake_dirent
 172 {
 173         __le32 inode;
 174         __le16 rec_len;
 175         u8 name_len;
 176         u8 file_type;
 177 };
 178
 179 struct dx_countlimit
 180 {
 181         __le16 limit;
 182         __le16 count;
 183 };
 184
 185 struct dx_entry
 186 {
 187         __le32 hash;
 188         __le32 block;
 189 };
 190
 191 /*
 192  * dx_root_info is laid out so that if it should somehow get overlaid by a
 193  * dirent the two low bits of the hash version will be zero.  Therefore, the
 194  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
 195  */
 196
 197 struct dx_root
 198 {
 199         struct fake_dirent dot;
 200         char dot_name[4];
 201         struct fake_dirent dotdot;
 202         char dotdot_name[4];
 203         struct dx_root_info
 204         {
 205                 __le32 reserved_zero;
 206                 u8 hash_version;
 207                 u8 info_length; /* 8 */
 208                 u8 indirect_levels;
 209                 u8 unused_flags;
 210         }
 211         info;
 212         struct dx_entry entries[0];
 213 };
 214
 215 struct dx_node
 216 {
 217         struct fake_dirent fake;
 218         struct dx_entry entries[0];
 219 };
 220
 221
 222 struct dx_frame
 223 {
 224         struct buffer_head *bh;
 225         struct dx_entry *entries;
 226         struct dx_entry *at;
 227 };
 228
 229 struct dx_map_entry
 230 {
 231         u32 hash;
 232         u16 offs;
 233         u16 size;
 234 };
 235
 236 /*
 237  * This goes at the end of each htree block.
 238  */
 239 struct dx_tail {
 240         u32 dt_reserved;
 241         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
 242 };
 243
 244 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
 245 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
 246 static inline unsigned dx_get_hash(struct dx_entry *entry);
 247 static void dx_set_hash(struct dx_entry *entry, unsigned value);
 248 static unsigned dx_get_count(struct dx_entry *entries);
 249 static unsigned dx_get_limit(struct dx_entry *entries);
 250 static void dx_set_count(struct dx_entry *entries, unsigned value);
 251 static void dx_set_limit(struct dx_entry *entries, unsigned value);
 252 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
 253 static unsigned dx_node_limit(struct inode *dir);
 254 static struct dx_frame *dx_probe(struct ext4_filename *fname,
 255                                  struct inode *dir,
 256                                  struct dx_hash_info *hinfo,
 257                                  struct dx_frame *frame);
 258 static void dx_release(struct dx_frame *frames);
 259 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
 260                        unsigned blocksize, struct dx_hash_info *hinfo,
 261                        struct dx_map_entry map[]);
 262 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
 263 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
 264                 struct dx_map_entry *offsets, int count, unsigned blocksize);
 265 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
 266 static void dx_insert_block(struct dx_frame *frame,
 267                                         u32 hash, ext4_lblk_t block);
 268 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 269                                  struct dx_frame *frame,
 270                                  struct dx_frame *frames,
 271                                  __u32 *start_hash);
 272 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 273                 struct ext4_filename *fname,
 274                 struct ext4_dir_entry_2 **res_dir);
 275 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
 276                              struct inode *dir, struct inode *inode);
 277
 278 /* checksumming functions */
 279 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
 280                             unsigned int blocksize)
 281 {
 282         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
 283         t->det_rec_len = ext4_rec_len_to_disk(
 284                         sizeof(struct ext4_dir_entry_tail), blocksize);
 285         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
 286 }
 287
 288 /* Walk through a dirent block to find a checksum "dirent" at the tail */
 289 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
 290                                                    struct ext4_dir_entry *de)
 291 {
 292         struct ext4_dir_entry_tail *t;
 293
 294 #ifdef PARANOID
 295         struct ext4_dir_entry *d, *top;
 296
 297         d = de;
 298         top = (struct ext4_dir_entry *)(((void *)de) +
 299                 (EXT4_BLOCK_SIZE(inode->i_sb) -
 300                 sizeof(struct ext4_dir_entry_tail)));
 301         while (d < top && d->rec_len)
 302                 d = (struct ext4_dir_entry *)(((void *)d) +
 303                     le16_to_cpu(d->rec_len));
 304
 305         if (d != top)
 306                 return NULL;
 307
 308         t = (struct ext4_dir_entry_tail *)d;
 309 #else
 310         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
 311 #endif
 312
 313         if (t->det_reserved_zero1 ||
 314             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
 315             t->det_reserved_zero2 ||
 316             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
 317                 return NULL;
 318
 319         return t;
 320 }
 321
 322 static __le32 ext4_dirent_csum(struct inode *inode,
 323                                struct ext4_dir_entry *dirent, int size)
 324 {
 325         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 326         struct ext4_inode_info *ei = EXT4_I(inode);
 327         __u32 csum;
 328
 329         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 330         return cpu_to_le32(csum);
 331 }
 332
 333 #define warn_no_space_for_csum(inode)                                   \
 334         __warn_no_space_for_csum((inode), __func__, __LINE__)
 335
 336 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
 337                                      unsigned int line)
 338 {
 339         __ext4_warning_inode(inode, func, line,
 340                 "No space for directory leaf checksum. Please run e2fsck -D.");
 341 }
 342
 343 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
 344 {
 345         struct ext4_dir_entry_tail *t;
 346
 347         if (!ext4_has_metadata_csum(inode->i_sb))
 348                 return 1;
 349
 350         t = get_dirent_tail(inode, dirent);
 351         if (!t) {
 352                 warn_no_space_for_csum(inode);
 353                 return 0;
 354         }
 355
 356         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
 357                                                 (void *)t - (void *)dirent))
 358                 return 0;
 359
 360         return 1;
 361 }
 362
 363 static void ext4_dirent_csum_set(struct inode *inode,
 364                                  struct ext4_dir_entry *dirent)
 365 {
 366         struct ext4_dir_entry_tail *t;
 367
 368         if (!ext4_has_metadata_csum(inode->i_sb))
 369                 return;
 370
 371         t = get_dirent_tail(inode, dirent);
 372         if (!t) {
 373                 warn_no_space_for_csum(inode);
 374                 return;
 375         }
 376
 377         t->det_checksum = ext4_dirent_csum(inode, dirent,
 378                                            (void *)t - (void *)dirent);
 379 }
 380
 381 int ext4_handle_dirty_dirent_node(handle_t *handle,
 382                                   struct inode *inode,
 383                                   struct buffer_head *bh)
 384 {
 385         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 386         return ext4_handle_dirty_metadata(handle, inode, bh);
 387 }
 388
 389 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
 390                                                struct ext4_dir_entry *dirent,
 391                                                int *offset)
 392 {
 393         struct ext4_dir_entry *dp;
 394         struct dx_root_info *root;
 395         int count_offset;
 396
 397         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
 398                 count_offset = 8;
 399         else if (le16_to_cpu(dirent->rec_len) == 12) {
 400                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
 401                 if (le16_to_cpu(dp->rec_len) !=
 402                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
 403                         return NULL;
 404                 root = (struct dx_root_info *)(((void *)dp + 12));
 405                 if (root->reserved_zero ||
 406                     root->info_length != sizeof(struct dx_root_info))
 407                         return NULL;
 408                 count_offset = 32;
 409         } else
 410                 return NULL;
 411
 412         if (offset)
 413                 *offset = count_offset;
 414         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
 415 }
 416
 417 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
 418                            int count_offset, int count, struct dx_tail *t)
 419 {
 420         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 421         struct ext4_inode_info *ei = EXT4_I(inode);
 422         __u32 csum;
 423         int size;
 424         __u32 dummy_csum = 0;
 425         int offset = offsetof(struct dx_tail, dt_checksum);
 426
 427         size = count_offset + (count * sizeof(struct dx_entry));
 428         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 429         csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
 430         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 431
 432         return cpu_to_le32(csum);
 433 }
 434
 435 static int ext4_dx_csum_verify(struct inode *inode,
 436                                struct ext4_dir_entry *dirent)
 437 {
 438         struct dx_countlimit *c;
 439         struct dx_tail *t;
 440         int count_offset, limit, count;
 441
 442         if (!ext4_has_metadata_csum(inode->i_sb))
 443                 return 1;
 444
 445         c = get_dx_countlimit(inode, dirent, &count_offset);
 446         if (!c) {
 447                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 448                 return 0;
 449         }
 450         limit = le16_to_cpu(c->limit);
 451         count = le16_to_cpu(c->count);
 452         if (count_offset + (limit * sizeof(struct dx_entry)) >
 453             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 454                 warn_no_space_for_csum(inode);
 455                 return 0;
 456         }
 457         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 458
 459         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
 460                                             count, t))
 461                 return 0;
 462         return 1;
 463 }
 464
 465 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
 466 {
 467         struct dx_countlimit *c;
 468         struct dx_tail *t;
 469         int count_offset, limit, count;
 470
 471         if (!ext4_has_metadata_csum(inode->i_sb))
 472                 return;
 473
 474         c = get_dx_countlimit(inode, dirent, &count_offset);
 475         if (!c) {
 476                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 477                 return;
 478         }
 479         limit = le16_to_cpu(c->limit);
 480         count = le16_to_cpu(c->count);
 481         if (count_offset + (limit * sizeof(struct dx_entry)) >
 482             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 483                 warn_no_space_for_csum(inode);
 484                 return;
 485         }
 486         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 487
 488         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
 489 }
 490
 491 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
 492                                             struct inode *inode,
 493                                             struct buffer_head *bh)
 494 {
 495         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 496         return ext4_handle_dirty_metadata(handle, inode, bh);
 497 }
 498
 499 /*
 500  * p is at least 6 bytes before the end of page
 501  */
 502 static inline struct ext4_dir_entry_2 *
 503 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
 504 {
 505         return (struct ext4_dir_entry_2 *)((char *)p +
 506                 ext4_rec_len_from_disk(p->rec_len, blocksize));
 507 }
 508
 509 /*
 510  * Future: use high four bits of block for coalesce-on-delete flags
 511  * Mask them off for now.
 512  */
 513
 514 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
 515 {
 516         return le32_to_cpu(entry->block) & 0x00ffffff;
 517 }
 518
 519 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
 520 {
 521         entry->block = cpu_to_le32(value);
 522 }
 523
 524 static inline unsigned dx_get_hash(struct dx_entry *entry)
 525 {
 526         return le32_to_cpu(entry->hash);
 527 }
 528
 529 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
 530 {
 531         entry->hash = cpu_to_le32(value);
 532 }
 533
 534 static inline unsigned dx_get_count(struct dx_entry *entries)
 535 {
 536         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
 537 }
 538
 539 static inline unsigned dx_get_limit(struct dx_entry *entries)
 540 {
 541         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
 542 }
 543
 544 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
 545 {
 546         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
 547 }
 548
 549 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
 550 {
 551         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
 552 }
 553
 554 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
 555 {
 556         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
 557                 EXT4_DIR_REC_LEN(2) - infosize;
 558
 559         if (ext4_has_metadata_csum(dir->i_sb))
 560                 entry_space -= sizeof(struct dx_tail);
 561         return entry_space / sizeof(struct dx_entry);
 562 }
 563
 564 static inline unsigned dx_node_limit(struct inode *dir)
 565 {
 566         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
 567
 568         if (ext4_has_metadata_csum(dir->i_sb))
 569                 entry_space -= sizeof(struct dx_tail);
 570         return entry_space / sizeof(struct dx_entry);
 571 }
 572
 573 /*
 574  * Debug
 575  */
 576 #ifdef DX_DEBUG
 577 static void dx_show_index(char * label, struct dx_entry *entries)
 578 {
 579         int i, n = dx_get_count (entries);
 580         printk(KERN_DEBUG "%s index ", label);
 581         for (i = 0; i < n; i++) {
 582                 printk("%x->%lu ", i ? dx_get_hash(entries + i) :
 583                                 0, (unsigned long)dx_get_block(entries + i));
 584         }
 585         printk("\n");
 586 }
 587
 588 struct stats
 589 {
 590         unsigned names;
 591         unsigned space;
 592         unsigned bcount;
 593 };
 594
 595 static struct stats dx_show_leaf(struct inode *dir,
 596                                 struct dx_hash_info *hinfo,
 597                                 struct ext4_dir_entry_2 *de,
 598                                 int size, int show_names)
 599 {
 600         unsigned names = 0, space = 0;
 601         char *base = (char *) de;
 602         struct dx_hash_info h = *hinfo;
 603
 604         printk("names: ");
 605         while ((char *) de < base + size)
 606         {
 607                 if (de->inode)
 608                 {
 609                         if (show_names)
 610                         {
 611 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 612                                 int len;
 613                                 char *name;
 614                                 struct fscrypt_str fname_crypto_str =
 615                                         FSTR_INIT(NULL, 0);
 616                                 int res = 0;
 617
 618                                 name  = de->name;
 619                                 len = de->name_len;
 620                                 if (ext4_encrypted_inode(dir))
 621                                         res = fscrypt_get_encryption_info(dir);
 622                                 if (res) {
 623                                         printk(KERN_WARNING "Error setting up"
 624                                                " fname crypto: %d\n", res);
 625                                 }
 626                                 if (!fscrypt_has_encryption_key(dir)) {
 627                                         /* Directory is not encrypted */
 628                                         ext4fs_dirhash(de->name,
 629                                                 de->name_len, &h);
 630                                         printk("%*.s:(U)%x.%u ", len,
 631                                                name, h.hash,
 632                                                (unsigned) ((char *) de
 633                                                            - base));
 634                                 } else {
 635                                         struct fscrypt_str de_name =
 636                                                 FSTR_INIT(name, len);
 637
 638                                         /* Directory is encrypted */
 639                                         res = fscrypt_fname_alloc_buffer(
 640                                                 dir, len,
 641                                                 &fname_crypto_str);
 642                                         if (res < 0)
 643                                                 printk(KERN_WARNING "Error "
 644                                                         "allocating crypto "
 645                                                         "buffer--skipping "
 646                                                         "crypto\n");
 647                                         res = fscrypt_fname_disk_to_usr(dir,
 648                                                 0, 0, &de_name,
 649                                                 &fname_crypto_str);
 650                                         if (res < 0) {
 651                                                 printk(KERN_WARNING "Error "
 652                                                         "converting filename "
 653                                                         "from disk to usr"
 654                                                         "\n");
 655                                                 name = "??";
 656                                                 len = 2;
 657                                         } else {
 658                                                 name = fname_crypto_str.name;
 659                                                 len = fname_crypto_str.len;
 660                                         }
 661                                         ext4fs_dirhash(de->name, de->name_len,
 662                                                        &h);
 663                                         printk("%*.s:(E)%x.%u ", len, name,
 664                                                h.hash, (unsigned) ((char *) de
 665                                                                    - base));
 666                                         fscrypt_fname_free_buffer(
 667                                                         &fname_crypto_str);
 668                                 }
 669 #else
 670                                 int len = de->name_len;
 671                                 char *name = de->name;
 672                                 ext4fs_dirhash(de->name, de->name_len, &h);
 673                                 printk("%*.s:%x.%u ", len, name, h.hash,
 674                                        (unsigned) ((char *) de - base));
 675 #endif
 676                         }
 677                         space += EXT4_DIR_REC_LEN(de->name_len);
 678                         names++;
 679                 }
 680                 de = ext4_next_entry(de, size);
 681         }
 682         printk("(%i)\n", names);
 683         return (struct stats) { names, space, 1 };
 684 }
 685
 686 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 687                              struct dx_entry *entries, int levels)
 688 {
 689         unsigned blocksize = dir->i_sb->s_blocksize;
 690         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
 691         unsigned bcount = 0;
 692         struct buffer_head *bh;
 693         printk("%i indexed blocks...\n", count);
 694         for (i = 0; i < count; i++, entries++)
 695         {
 696                 ext4_lblk_t block = dx_get_block(entries);
 697                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
 698                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
 699                 struct stats stats;
 700                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
 701                 bh = ext4_bread(NULL,dir, block, 0);
 702                 if (!bh || IS_ERR(bh))
 703                         continue;
 704                 stats = levels?
 705                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
 706                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
 707                         bh->b_data, blocksize, 0);
 708                 names += stats.names;
 709                 space += stats.space;
 710                 bcount += stats.bcount;
 711                 brelse(bh);
 712         }
 713         if (bcount)
 714                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
 715                        levels ? "" : "   ", names, space/bcount,
 716                        (space/bcount)*100/blocksize);
 717         return (struct stats) { names, space, bcount};
 718 }
 719 #endif /* DX_DEBUG */
 720
 721 /*
 722  * Probe for a directory leaf block to search.
 723  *
 724  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
 725  * error in the directory index, and the caller should fall back to
 726  * searching the directory normally.  The callers of dx_probe **MUST**
 727  * check for this error code, and make sure it never gets reflected
 728  * back to userspace.
 729  */
 730 static struct dx_frame *
 731 dx_probe(struct ext4_filename *fname, struct inode *dir,
 732          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
 733 {
 734         unsigned count, indirect;
 735         struct dx_entry *at, *entries, *p, *q, *m;
 736         struct dx_root *root;
 737         struct dx_frame *frame = frame_in;
 738         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
 739         u32 hash;
 740
 741         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
 742         if (IS_ERR(frame->bh))
 743                 return (struct dx_frame *) frame->bh;
 744
 745         root = (struct dx_root *) frame->bh->b_data;
 746         if (root->info.hash_version != DX_HASH_TEA &&
 747             root->info.hash_version != DX_HASH_HALF_MD4 &&
 748             root->info.hash_version != DX_HASH_LEGACY) {
 749                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
 750                                    root->info.hash_version);
 751                 goto fail;
 752         }
 753         if (fname)
 754                 hinfo = &fname->hinfo;
 755         hinfo->hash_version = root->info.hash_version;
 756         if (hinfo->hash_version <= DX_HASH_TEA)
 757                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 758         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 759         if (fname && fname_name(fname))
 760                 ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
 761         hash = hinfo->hash;
 762
 763         if (root->info.unused_flags & 1) {
 764                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
 765                                    root->info.unused_flags);
 766                 goto fail;
 767         }
 768
 769         indirect = root->info.indirect_levels;
 770         if (indirect > 1) {
 771                 ext4_warning_inode(dir, "Unimplemented hash depth: %#06x",
 772                                    root->info.indirect_levels);
 773                 goto fail;
 774         }
 775
 776         entries = (struct dx_entry *)(((char *)&root->info) +
 777                                       root->info.info_length);
 778
 779         if (dx_get_limit(entries) != dx_root_limit(dir,
 780                                                    root->info.info_length)) {
 781                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 782                                    dx_get_limit(entries),
 783                                    dx_root_limit(dir, root->info.info_length));
 784                 goto fail;
 785         }
 786
 787         dxtrace(printk("Look up %x", hash));
 788         while (1) {
 789                 count = dx_get_count(entries);
 790                 if (!count || count > dx_get_limit(entries)) {
 791                         ext4_warning_inode(dir,
 792                                            "dx entry: count %u beyond limit %u",
 793                                            count, dx_get_limit(entries));
 794                         goto fail;
 795                 }
 796
 797                 p = entries + 1;
 798                 q = entries + count - 1;
 799                 while (p <= q) {
 800                         m = p + (q - p) / 2;
 801                         dxtrace(printk("."));
 802                         if (dx_get_hash(m) > hash)
 803                                 q = m - 1;
 804                         else
 805                                 p = m + 1;
 806                 }
 807
 808                 if (0) { // linear search cross check
 809                         unsigned n = count - 1;
 810                         at = entries;
 811                         while (n--)
 812                         {
 813                                 dxtrace(printk(","));
 814                                 if (dx_get_hash(++at) > hash)
 815                                 {
 816                                         at--;
 817                                         break;
 818                                 }
 819                         }
 820                         assert (at == p - 1);
 821                 }
 822
 823                 at = p - 1;
 824                 dxtrace(printk(" %x->%u\n", at == entries ? 0 : dx_get_hash(at),
 825                                dx_get_block(at)));
 826                 frame->entries = entries;
 827                 frame->at = at;
 828                 if (!indirect--)
 829                         return frame;
 830                 frame++;
 831                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
 832                 if (IS_ERR(frame->bh)) {
 833                         ret_err = (struct dx_frame *) frame->bh;
 834                         frame->bh = NULL;
 835                         goto fail;
 836                 }
 837                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
 838
 839                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
 840                         ext4_warning_inode(dir,
 841                                 "dx entry: limit %u != node limit %u",
 842                                 dx_get_limit(entries), dx_node_limit(dir));
 843                         goto fail;
 844                 }
 845         }
 846 fail:
 847         while (frame >= frame_in) {
 848                 brelse(frame->bh);
 849                 frame--;
 850         }
 851
 852         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
 853                 ext4_warning_inode(dir,
 854                         "Corrupt directory, running e2fsck is recommended");
 855         return ret_err;
 856 }
 857
 858 static void dx_release(struct dx_frame *frames)
 859 {
 860         if (frames[0].bh == NULL)
 861                 return;
 862
 863         if (((struct dx_root *)frames[0].bh->b_data)->info.indirect_levels)
 864                 brelse(frames[1].bh);
 865         brelse(frames[0].bh);
 866 }
 867
 868 /*
 869  * This function increments the frame pointer to search the next leaf
 870  * block, and reads in the necessary intervening nodes if the search
 871  * should be necessary.  Whether or not the search is necessary is
 872  * controlled by the hash parameter.  If the hash value is even, then
 873  * the search is only continued if the next block starts with that
 874  * hash value.  This is used if we are searching for a specific file.
 875  *
 876  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
 877  *
 878  * This function returns 1 if the caller should continue to search,
 879  * or 0 if it should not.  If there is an error reading one of the
 880  * index blocks, it will a negative error code.
 881  *
 882  * If start_hash is non-null, it will be filled in with the starting
 883  * hash of the next page.
 884  */
 885 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 886                                  struct dx_frame *frame,
 887                                  struct dx_frame *frames,
 888                                  __u32 *start_hash)
 889 {
 890         struct dx_frame *p;
 891         struct buffer_head *bh;
 892         int num_frames = 0;
 893         __u32 bhash;
 894
 895         p = frame;
 896         /*
 897          * Find the next leaf page by incrementing the frame pointer.
 898          * If we run out of entries in the interior node, loop around and
 899          * increment pointer in the parent node.  When we break out of
 900          * this loop, num_frames indicates the number of interior
 901          * nodes need to be read.
 902          */
 903         while (1) {
 904                 if (++(p->at) < p->entries + dx_get_count(p->entries))
 905                         break;
 906                 if (p == frames)
 907                         return 0;
 908                 num_frames++;
 909                 p--;
 910         }
 911
 912         /*
 913          * If the hash is 1, then continue only if the next page has a
 914          * continuation hash of any value.  This is used for readdir
 915          * handling.  Otherwise, check to see if the hash matches the
 916          * desired contiuation hash.  If it doesn't, return since
 917          * there's no point to read in the successive index pages.
 918          */
 919         bhash = dx_get_hash(p->at);
 920         if (start_hash)
 921                 *start_hash = bhash;
 922         if ((hash & 1) == 0) {
 923                 if ((bhash & ~1) != hash)
 924                         return 0;
 925         }
 926         /*
 927          * If the hash is HASH_NB_ALWAYS, we always go to the next
 928          * block so no check is necessary
 929          */
 930         while (num_frames--) {
 931                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
 932                 if (IS_ERR(bh))
 933                         return PTR_ERR(bh);
 934                 p++;
 935                 brelse(p->bh);
 936                 p->bh = bh;
 937                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
 938         }
 939         return 1;
 940 }
 941
 942
 943 /*
 944  * This function fills a red-black tree with information from a
 945  * directory block.  It returns the number directory entries loaded
 946  * into the tree.  If there is an error it is returned in err.
 947  */
 948 static int htree_dirblock_to_tree(struct file *dir_file,
 949                                   struct inode *dir, ext4_lblk_t block,
 950                                   struct dx_hash_info *hinfo,
 951                                   __u32 start_hash, __u32 start_minor_hash)
 952 {
 953         struct buffer_head *bh;
 954         struct ext4_dir_entry_2 *de, *top;
 955         int err = 0, count = 0;
 956         struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
 957
 958         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 959                                                         (unsigned long)block));
 960         bh = ext4_read_dirblock(dir, block, DIRENT);
 961         if (IS_ERR(bh))
 962                 return PTR_ERR(bh);
 963
 964         de = (struct ext4_dir_entry_2 *) bh->b_data;
 965         top = (struct ext4_dir_entry_2 *) ((char *) de +
 966                                            dir->i_sb->s_blocksize -
 967                                            EXT4_DIR_REC_LEN(0));
 968 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 969         /* Check if the directory is encrypted */
 970         if (ext4_encrypted_inode(dir)) {
 971                 err = fscrypt_get_encryption_info(dir);
 972                 if (err < 0) {
 973                         brelse(bh);
 974                         return err;
 975                 }
 976                 err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
 977                                                      &fname_crypto_str);
 978                 if (err < 0) {
 979                         brelse(bh);
 980                         return err;
 981                 }
 982         }
 983 #endif
 984         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
 985                 if (ext4_check_dir_entry(dir, NULL, de, bh,
 986                                 bh->b_data, bh->b_size,
 987                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
 988                                          + ((char *)de - bh->b_data))) {
 989                         /* silently ignore the rest of the block */
 990                         break;
 991                 }
 992                 ext4fs_dirhash(de->name, de->name_len, hinfo);
 993                 if ((hinfo->hash < start_hash) ||
 994                     ((hinfo->hash == start_hash) &&
 995                      (hinfo->minor_hash < start_minor_hash)))
 996                         continue;
 997                 if (de->inode == 0)
 998                         continue;
 999                 if (!ext4_encrypted_inode(dir)) {
1000                         tmp_str.name = de->name;
1001                         tmp_str.len = de->name_len;
1002                         err = ext4_htree_store_dirent(dir_file,
1003                                    hinfo->hash, hinfo->minor_hash, de,
1004                                    &tmp_str);
1005                 } else {
1006                         int save_len = fname_crypto_str.len;
1007                         struct fscrypt_str de_name = FSTR_INIT(de->name,
1008                                                                 de->name_len);
1009
1010                         /* Directory is encrypted */
1011                         err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1012                                         hinfo->minor_hash, &de_name,
1013                                         &fname_crypto_str);
1014                         if (err < 0) {
1015                                 count = err;
1016                                 goto errout;
1017                         }
1018                         err = ext4_htree_store_dirent(dir_file,
1019                                    hinfo->hash, hinfo->minor_hash, de,
1020                                         &fname_crypto_str);
1021                         fname_crypto_str.len = save_len;
1022                 }
1023                 if (err != 0) {
1024                         count = err;
1025                         goto errout;
1026                 }
1027                 count++;
1028         }
1029 errout:
1030         brelse(bh);
1031 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1032         fscrypt_fname_free_buffer(&fname_crypto_str);
1033 #endif
1034         return count;
1035 }
1036
1037
1038 /*
1039  * This function fills a red-black tree with information from a
1040  * directory.  We start scanning the directory in hash order, starting
1041  * at start_hash and start_minor_hash.
1042  *
1043  * This function returns the number of entries inserted into the tree,
1044  * or a negative error code.
1045  */
1046 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1047                          __u32 start_minor_hash, __u32 *next_hash)
1048 {
1049         struct dx_hash_info hinfo;
1050         struct ext4_dir_entry_2 *de;
1051         struct dx_frame frames[2], *frame;
1052         struct inode *dir;
1053         ext4_lblk_t block;
1054         int count = 0;
1055         int ret, err;
1056         __u32 hashval;
1057         struct fscrypt_str tmp_str;
1058
1059         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1060                        start_hash, start_minor_hash));
1061         dir = file_inode(dir_file);
1062         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1063                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1064                 if (hinfo.hash_version <= DX_HASH_TEA)
1065                         hinfo.hash_version +=
1066                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1067                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1068                 if (ext4_has_inline_data(dir)) {
1069                         int has_inline_data = 1;
1070                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
1071                                                         &hinfo, start_hash,
1072                                                         start_minor_hash,
1073                                                         &has_inline_data);
1074                         if (has_inline_data) {
1075                                 *next_hash = ~0;
1076                                 return count;
1077                         }
1078                 }
1079                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1080                                                start_hash, start_minor_hash);
1081                 *next_hash = ~0;
1082                 return count;
1083         }
1084         hinfo.hash = start_hash;
1085         hinfo.minor_hash = 0;
1086         frame = dx_probe(NULL, dir, &hinfo, frames);
1087         if (IS_ERR(frame))
1088                 return PTR_ERR(frame);
1089
1090         /* Add '.' and '..' from the htree header */
1091         if (!start_hash && !start_minor_hash) {
1092                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1093                 tmp_str.name = de->name;
1094                 tmp_str.len = de->name_len;
1095                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1096                                               de, &tmp_str);
1097                 if (err != 0)
1098                         goto errout;
1099                 count++;
1100         }
1101         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1102                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1103                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1104                 tmp_str.name = de->name;
1105                 tmp_str.len = de->name_len;
1106                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1107                                               de, &tmp_str);
1108                 if (err != 0)
1109                         goto errout;
1110                 count++;
1111         }
1112
1113         while (1) {
1114                 if (fatal_signal_pending(current)) {
1115                         err = -ERESTARTSYS;
1116                         goto errout;
1117                 }
1118                 cond_resched();
1119                 block = dx_get_block(frame->at);
1120                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1121                                              start_hash, start_minor_hash);
1122                 if (ret < 0) {
1123                         err = ret;
1124                         goto errout;
1125                 }
1126                 count += ret;
1127                 hashval = ~0;
1128                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1129                                             frame, frames, &hashval);
1130                 *next_hash = hashval;
1131                 if (ret < 0) {
1132                         err = ret;
1133                         goto errout;
1134                 }
1135                 /*
1136                  * Stop if:  (a) there are no more entries, or
1137                  * (b) we have inserted at least one entry and the
1138                  * next hash value is not a continuation
1139                  */
1140                 if ((ret == 0) ||
1141                     (count && ((hashval & 1) == 0)))
1142                         break;
1143         }
1144         dx_release(frames);
1145         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1146                        "next hash: %x\n", count, *next_hash));
1147         return count;
1148 errout:
1149         dx_release(frames);
1150         return (err);
1151 }
1152
1153 static inline int search_dirblock(struct buffer_head *bh,
1154                                   struct inode *dir,
1155                                   struct ext4_filename *fname,
1156                                   const struct qstr *d_name,
1157                                   unsigned int offset,
1158                                   struct ext4_dir_entry_2 **res_dir)
1159 {
1160         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1161                                fname, d_name, offset, res_dir);
1162 }
1163
1164 /*
1165  * Directory block splitting, compacting
1166  */
1167
1168 /*
1169  * Create map of hash values, offsets, and sizes, stored at end of block.
1170  * Returns number of entries mapped.
1171  */
1172 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
1173                        unsigned blocksize, struct dx_hash_info *hinfo,
1174                        struct dx_map_entry *map_tail)
1175 {
1176         int count = 0;
1177         char *base = (char *) de;
1178         struct dx_hash_info h = *hinfo;
1179
1180         while ((char *) de < base + blocksize) {
1181                 if (de->name_len && de->inode) {
1182                         ext4fs_dirhash(de->name, de->name_len, &h);
1183                         map_tail--;
1184                         map_tail->hash = h.hash;
1185                         map_tail->offs = ((char *) de - base)>>2;
1186                         map_tail->size = le16_to_cpu(de->rec_len);
1187                         count++;
1188                         cond_resched();
1189                 }
1190                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1191                 de = ext4_next_entry(de, blocksize);
1192         }
1193         return count;
1194 }
1195
1196 /* Sort map by hash value */
1197 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1198 {
1199         struct dx_map_entry *p, *q, *top = map + count - 1;
1200         int more;
1201         /* Combsort until bubble sort doesn't suck */
1202         while (count > 2) {
1203                 count = count*10/13;
1204                 if (count - 9 < 2) /* 9, 10 -> 11 */
1205                         count = 11;
1206                 for (p = top, q = p - count; q >= map; p--, q--)
1207                         if (p->hash < q->hash)
1208                                 swap(*p, *q);
1209         }
1210         /* Garden variety bubble sort */
1211         do {
1212                 more = 0;
1213                 q = top;
1214                 while (q-- > map) {
1215                         if (q[1].hash >= q[0].hash)
1216                                 continue;
1217                         swap(*(q+1), *q);
1218                         more = 1;
1219                 }
1220         } while(more);
1221 }
1222
1223 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1224 {
1225         struct dx_entry *entries = frame->entries;
1226         struct dx_entry *old = frame->at, *new = old + 1;
1227         int count = dx_get_count(entries);
1228
1229         assert(count < dx_get_limit(entries));
1230         assert(old < entries + count);
1231         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1232         dx_set_hash(new, hash);
1233         dx_set_block(new, block);
1234         dx_set_count(entries, count + 1);
1235 }
1236
1237 /*
1238  * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.
1239  *
1240  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
1241  * `de != NULL' is guaranteed by caller.
1242  */
1243 static inline int ext4_match(struct ext4_filename *fname,
1244                              struct ext4_dir_entry_2 *de)
1245 {
1246         const void *name = fname_name(fname);
1247         u32 len = fname_len(fname);
1248
1249         if (!de->inode)
1250                 return 0;
1251
1252 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1253         if (unlikely(!name)) {
1254                 if (fname->usr_fname->name[0] == '_') {
1255                         int ret;
1256                         if (de->name_len < 16)
1257                                 return 0;
1258                         ret = memcmp(de->name + de->name_len - 16,
1259                                      fname->crypto_buf.name + 8, 16);
1260                         return (ret == 0) ? 1 : 0;
1261                 }
1262                 name = fname->crypto_buf.name;
1263                 len = fname->crypto_buf.len;
1264         }
1265 #endif
1266         if (de->name_len != len)
1267                 return 0;
1268         return (memcmp(de->name, name, len) == 0) ? 1 : 0;
1269 }
1270
1271 /*
1272  * Returns 0 if not found, -1 on failure, and 1 on success
1273  */
1274 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1275                     struct inode *dir, struct ext4_filename *fname,
1276                     const struct qstr *d_name,
1277                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1278 {
1279         struct ext4_dir_entry_2 * de;
1280         char * dlimit;
1281         int de_len;
1282         int res;
1283
1284         de = (struct ext4_dir_entry_2 *)search_buf;
1285         dlimit = search_buf + buf_size;
1286         while ((char *) de < dlimit) {
1287                 /* this code is executed quadratically often */
1288                 /* do minimal checking `by hand' */
1289                 if ((char *) de + de->name_len <= dlimit) {
1290                         res = ext4_match(fname, de);
1291                         if (res < 0) {
1292                                 res = -1;
1293                                 goto return_result;
1294                         }
1295                         if (res > 0) {
1296                                 /* found a match - just to be sure, do
1297                                  * a full check */
1298                                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1299                                                 bh->b_data,
1300                                                  bh->b_size, offset)) {
1301                                         res = -1;
1302                                         goto return_result;
1303                                 }
1304                                 *res_dir = de;
1305                                 res = 1;
1306                                 goto return_result;
1307                         }
1308
1309                 }
1310                 /* prevent looping on a bad block */
1311                 de_len = ext4_rec_len_from_disk(de->rec_len,
1312                                                 dir->i_sb->s_blocksize);
1313                 if (de_len <= 0) {
1314                         res = -1;
1315                         goto return_result;
1316                 }
1317                 offset += de_len;
1318                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1319         }
1320
1321         res = 0;
1322 return_result:
1323         return res;
1324 }
1325
1326 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1327                                struct ext4_dir_entry *de)
1328 {
1329         struct super_block *sb = dir->i_sb;
1330
1331         if (!is_dx(dir))
1332                 return 0;
1333         if (block == 0)
1334                 return 1;
1335         if (de->inode == 0 &&
1336             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1337                         sb->s_blocksize)
1338                 return 1;
1339         return 0;
1340 }
1341
1342 /*
1343  *      ext4_find_entry()
1344  *
1345  * finds an entry in the specified directory with the wanted name. It
1346  * returns the cache buffer in which the entry was found, and the entry
1347  * itself (as a parameter - res_dir). It does NOT read the inode of the
1348  * entry - you'll have to do that yourself if you want to.
1349  *
1350  * The returned buffer_head has ->b_count elevated.  The caller is expected
1351  * to brelse() it when appropriate.
1352  */
1353 static struct buffer_head * ext4_find_entry (struct inode *dir,
1354                                         const struct qstr *d_name,
1355                                         struct ext4_dir_entry_2 **res_dir,
1356                                         int *inlined)
1357 {
1358         struct super_block *sb;
1359         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1360         struct buffer_head *bh, *ret = NULL;
1361         ext4_lblk_t start, block, b;
1362         const u8 *name = d_name->name;
1363         int ra_max = 0;         /* Number of bh's in the readahead
1364                                    buffer, bh_use[] */
1365         int ra_ptr = 0;         /* Current index into readahead
1366                                    buffer */
1367         int num = 0;
1368         ext4_lblk_t  nblocks;
1369         int i, namelen, retval;
1370         struct ext4_filename fname;
1371
1372         *res_dir = NULL;
1373         sb = dir->i_sb;
1374         namelen = d_name->len;
1375         if (namelen > EXT4_NAME_LEN)
1376                 return NULL;
1377
1378         retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1379         if (retval)
1380                 return ERR_PTR(retval);
1381
1382         if (ext4_has_inline_data(dir)) {
1383                 int has_inline_data = 1;
1384                 ret = ext4_find_inline_entry(dir, &fname, d_name, res_dir,
1385                                              &has_inline_data);
1386                 if (has_inline_data) {
1387                         if (inlined)
1388                                 *inlined = 1;
1389                         goto cleanup_and_exit;
1390                 }
1391         }
1392
1393         if ((namelen <= 2) && (name[0] == '.') &&
1394             (name[1] == '.' || name[1] == '\0')) {
1395                 /*
1396                  * "." or ".." will only be in the first block
1397                  * NFS may look up ".."; "." should be handled by the VFS
1398                  */
1399                 block = start = 0;
1400                 nblocks = 1;
1401                 goto restart;
1402         }
1403         if (is_dx(dir)) {
1404                 ret = ext4_dx_find_entry(dir, &fname, res_dir);
1405                 /*
1406                  * On success, or if the error was file not found,
1407                  * return.  Otherwise, fall back to doing a search the
1408                  * old fashioned way.
1409                  */
1410                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1411                         goto cleanup_and_exit;
1412                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1413                                "falling back\n"));
1414         }
1415         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1416         start = EXT4_I(dir)->i_dir_start_lookup;
1417         if (start >= nblocks)
1418                 start = 0;
1419         block = start;
1420 restart:
1421         do {
1422                 /*
1423                  * We deal with the read-ahead logic here.
1424                  */
1425                 if (ra_ptr >= ra_max) {
1426                         /* Refill the readahead buffer */
1427                         ra_ptr = 0;
1428                         b = block;
1429                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
1430                                 /*
1431                                  * Terminate if we reach the end of the
1432                                  * directory and must wrap, or if our
1433                                  * search has finished at this block.
1434                                  */
1435                                 if (b >= nblocks || (num && block == start)) {
1436                                         bh_use[ra_max] = NULL;
1437                                         break;
1438                                 }
1439                                 num++;
1440                                 bh = ext4_getblk(NULL, dir, b++, 0);
1441                                 if (IS_ERR(bh)) {
1442                                         if (ra_max == 0) {
1443                                                 ret = bh;
1444                                                 goto cleanup_and_exit;
1445                                         }
1446                                         break;
1447                                 }
1448                                 bh_use[ra_max] = bh;
1449                                 if (bh)
1450                                         ll_rw_block(REQ_OP_READ,
1451                                                     REQ_META | REQ_PRIO,
1452                                                     1, &bh);
1453                         }
1454                 }
1455                 if ((bh = bh_use[ra_ptr++]) == NULL)
1456                         goto next;
1457                 wait_on_buffer(bh);
1458                 if (!buffer_uptodate(bh)) {
1459                         /* read error, skip block & hope for the best */
1460                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1461                                          (unsigned long) block);
1462                         brelse(bh);
1463                         goto next;
1464                 }
1465                 if (!buffer_verified(bh) &&
1466                     !is_dx_internal_node(dir, block,
1467                                          (struct ext4_dir_entry *)bh->b_data) &&
1468                     !ext4_dirent_csum_verify(dir,
1469                                 (struct ext4_dir_entry *)bh->b_data)) {
1470                         EXT4_ERROR_INODE(dir, "checksumming directory "
1471                                          "block %lu", (unsigned long)block);
1472                         brelse(bh);
1473                         goto next;
1474                 }
1475                 set_buffer_verified(bh);
1476                 i = search_dirblock(bh, dir, &fname, d_name,
1477                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1478                 if (i == 1) {
1479                         EXT4_I(dir)->i_dir_start_lookup = block;
1480                         ret = bh;
1481                         goto cleanup_and_exit;
1482                 } else {
1483                         brelse(bh);
1484                         if (i < 0)
1485                                 goto cleanup_and_exit;
1486                 }
1487         next:
1488                 if (++block >= nblocks)
1489                         block = 0;
1490         } while (block != start);
1491
1492         /*
1493          * If the directory has grown while we were searching, then
1494          * search the last part of the directory before giving up.
1495          */
1496         block = nblocks;
1497         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1498         if (block < nblocks) {
1499                 start = 0;
1500                 goto restart;
1501         }
1502
1503 cleanup_and_exit:
1504         /* Clean up the read-ahead blocks */
1505         for (; ra_ptr < ra_max; ra_ptr++)
1506                 brelse(bh_use[ra_ptr]);
1507         ext4_fname_free_filename(&fname);
1508         return ret;
1509 }
1510
1511 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1512                         struct ext4_filename *fname,
1513                         struct ext4_dir_entry_2 **res_dir)
1514 {
1515         struct super_block * sb = dir->i_sb;
1516         struct dx_frame frames[2], *frame;
1517         const struct qstr *d_name = fname->usr_fname;
1518         struct buffer_head *bh;
1519         ext4_lblk_t block;
1520         int retval;
1521
1522 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1523         *res_dir = NULL;
1524 #endif
1525         frame = dx_probe(fname, dir, NULL, frames);
1526         if (IS_ERR(frame))
1527                 return (struct buffer_head *) frame;
1528         do {
1529                 block = dx_get_block(frame->at);
1530                 bh = ext4_read_dirblock(dir, block, DIRENT);
1531                 if (IS_ERR(bh))
1532                         goto errout;
1533
1534                 retval = search_dirblock(bh, dir, fname, d_name,
1535                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1536                                          res_dir);
1537                 if (retval == 1)
1538                         goto success;
1539                 brelse(bh);
1540                 if (retval == -1) {
1541                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1542                         goto errout;
1543                 }
1544
1545                 /* Check to see if we should continue to search */
1546                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1547                                                frames, NULL);
1548                 if (retval < 0) {
1549                         ext4_warning_inode(dir,
1550                                 "error %d reading directory index block",
1551                                 retval);
1552                         bh = ERR_PTR(retval);
1553                         goto errout;
1554                 }
1555         } while (retval == 1);
1556
1557         bh = NULL;
1558 errout:
1559         dxtrace(printk(KERN_DEBUG "%s not found\n", d_name->name));
1560 success:
1561         dx_release(frames);
1562         return bh;
1563 }
1564
1565 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1566 {
1567         struct inode *inode;
1568         struct ext4_dir_entry_2 *de;
1569         struct buffer_head *bh;
1570
1571         if (ext4_encrypted_inode(dir)) {
1572                 int res = fscrypt_get_encryption_info(dir);
1573
1574                 /*
1575                  * DCACHE_ENCRYPTED_WITH_KEY is set if the dentry is
1576                  * created while the directory was encrypted and we
1577                  * have access to the key.
1578                  */
1579                 if (fscrypt_has_encryption_key(dir))
1580                         fscrypt_set_encrypted_dentry(dentry);
1581                 fscrypt_set_d_op(dentry);
1582                 if (res && res != -ENOKEY)
1583                         return ERR_PTR(res);
1584         }
1585
1586        if (dentry->d_name.len > EXT4_NAME_LEN)
1587                return ERR_PTR(-ENAMETOOLONG);
1588
1589         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1590         if (IS_ERR(bh))
1591                 return (struct dentry *) bh;
1592         inode = NULL;
1593         if (bh) {
1594                 __u32 ino = le32_to_cpu(de->inode);
1595                 brelse(bh);
1596                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1597                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1598                         return ERR_PTR(-EFSCORRUPTED);
1599                 }
1600                 if (unlikely(ino == dir->i_ino)) {
1601                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1602                                          dentry);
1603                         return ERR_PTR(-EFSCORRUPTED);
1604                 }
1605                 inode = ext4_iget_normal(dir->i_sb, ino);
1606                 if (inode == ERR_PTR(-ESTALE)) {
1607                         EXT4_ERROR_INODE(dir,
1608                                          "deleted inode referenced: %u",
1609                                          ino);
1610                         return ERR_PTR(-EFSCORRUPTED);
1611                 }
1612                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1613                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1614                     !fscrypt_has_permitted_context(dir, inode)) {
1615                         int nokey = ext4_encrypted_inode(inode) &&
1616                                 !fscrypt_has_encryption_key(inode);
1617                         iput(inode);
1618                         if (nokey)
1619                                 return ERR_PTR(-ENOKEY);
1620                         ext4_warning(inode->i_sb,
1621                                      "Inconsistent encryption contexts: %lu/%lu",
1622                                      (unsigned long) dir->i_ino,
1623                                      (unsigned long) inode->i_ino);
1624                         return ERR_PTR(-EPERM);
1625                 }
1626         }
1627         return d_splice_alias(inode, dentry);
1628 }
1629
1630
1631 struct dentry *ext4_get_parent(struct dentry *child)
1632 {
1633         __u32 ino;
1634         static const struct qstr dotdot = QSTR_INIT("..", 2);
1635         struct ext4_dir_entry_2 * de;
1636         struct buffer_head *bh;
1637
1638         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1639         if (IS_ERR(bh))
1640                 return (struct dentry *) bh;
1641         if (!bh)
1642                 return ERR_PTR(-ENOENT);
1643         ino = le32_to_cpu(de->inode);
1644         brelse(bh);
1645
1646         if (!ext4_valid_inum(child->d_sb, ino)) {
1647                 EXT4_ERROR_INODE(d_inode(child),
1648                                  "bad parent inode number: %u", ino);
1649                 return ERR_PTR(-EFSCORRUPTED);
1650         }
1651
1652         return d_obtain_alias(ext4_iget_normal(child->d_sb, ino));
1653 }
1654
1655 /*
1656  * Move count entries from end of map between two memory locations.
1657  * Returns pointer to last entry moved.
1658  */
1659 static struct ext4_dir_entry_2 *
1660 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1661                 unsigned blocksize)
1662 {
1663         unsigned rec_len = 0;
1664
1665         while (count--) {
1666                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1667                                                 (from + (map->offs<<2));
1668                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1669                 memcpy (to, de, rec_len);
1670                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1671                                 ext4_rec_len_to_disk(rec_len, blocksize);
1672                 de->inode = 0;
1673                 map++;
1674                 to += rec_len;
1675         }
1676         return (struct ext4_dir_entry_2 *) (to - rec_len);
1677 }
1678
1679 /*
1680  * Compact each dir entry in the range to the minimal rec_len.
1681  * Returns pointer to last entry in range.
1682  */
1683 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1684 {
1685         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1686         unsigned rec_len = 0;
1687
1688         prev = to = de;
1689         while ((char*)de < base + blocksize) {
1690                 next = ext4_next_entry(de, blocksize);
1691                 if (de->inode && de->name_len) {
1692                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1693                         if (de > to)
1694                                 memmove(to, de, rec_len);
1695                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1696                         prev = to;
1697                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1698                 }
1699                 de = next;
1700         }
1701         return prev;
1702 }
1703
1704 /*
1705  * Split a full leaf block to make room for a new dir entry.
1706  * Allocate a new block, and move entries so that they are approx. equally full.
1707  * Returns pointer to de in block into which the new entry will be inserted.
1708  */
1709 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1710                         struct buffer_head **bh,struct dx_frame *frame,
1711                         struct dx_hash_info *hinfo)
1712 {
1713         unsigned blocksize = dir->i_sb->s_blocksize;
1714         unsigned count, continued;
1715         struct buffer_head *bh2;
1716         ext4_lblk_t newblock;
1717         u32 hash2;
1718         struct dx_map_entry *map;
1719         char *data1 = (*bh)->b_data, *data2;
1720         unsigned split, move, size;
1721         struct ext4_dir_entry_2 *de = NULL, *de2;
1722         struct ext4_dir_entry_tail *t;
1723         int     csum_size = 0;
1724         int     err = 0, i;
1725
1726         if (ext4_has_metadata_csum(dir->i_sb))
1727                 csum_size = sizeof(struct ext4_dir_entry_tail);
1728
1729         bh2 = ext4_append(handle, dir, &newblock);
1730         if (IS_ERR(bh2)) {
1731                 brelse(*bh);
1732                 *bh = NULL;
1733                 return (struct ext4_dir_entry_2 *) bh2;
1734         }
1735
1736         BUFFER_TRACE(*bh, "get_write_access");
1737         err = ext4_journal_get_write_access(handle, *bh);
1738         if (err)
1739                 goto journal_error;
1740
1741         BUFFER_TRACE(frame->bh, "get_write_access");
1742         err = ext4_journal_get_write_access(handle, frame->bh);
1743         if (err)
1744                 goto journal_error;
1745
1746         data2 = bh2->b_data;
1747
1748         /* create map in the end of data2 block */
1749         map = (struct dx_map_entry *) (data2 + blocksize);
1750         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1751                              blocksize, hinfo, map);
1752         map -= count;
1753         dx_sort_map(map, count);
1754         /* Split the existing block in the middle, size-wise */
1755         size = 0;
1756         move = 0;
1757         for (i = count-1; i >= 0; i--) {
1758                 /* is more than half of this entry in 2nd half of the block? */
1759                 if (size + map[i].size/2 > blocksize/2)
1760                         break;
1761                 size += map[i].size;
1762                 move++;
1763         }
1764         /* map index at which we will split */
1765         split = count - move;
1766         hash2 = map[split].hash;
1767         continued = hash2 == map[split - 1].hash;
1768         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1769                         (unsigned long)dx_get_block(frame->at),
1770                                         hash2, split, count-split));
1771
1772         /* Fancy dance to stay within two buffers */
1773         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1774                               blocksize);
1775         de = dx_pack_dirents(data1, blocksize);
1776         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1777                                            (char *) de,
1778                                            blocksize);
1779         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1780                                             (char *) de2,
1781                                             blocksize);
1782         if (csum_size) {
1783                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1784                 initialize_dirent_tail(t, blocksize);
1785
1786                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1787                 initialize_dirent_tail(t, blocksize);
1788         }
1789
1790         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1791                         blocksize, 1));
1792         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1793                         blocksize, 1));
1794
1795         /* Which block gets the new entry? */
1796         if (hinfo->hash >= hash2) {
1797                 swap(*bh, bh2);
1798                 de = de2;
1799         }
1800         dx_insert_block(frame, hash2 + continued, newblock);
1801         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1802         if (err)
1803                 goto journal_error;
1804         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1805         if (err)
1806                 goto journal_error;
1807         brelse(bh2);
1808         dxtrace(dx_show_index("frame", frame->entries));
1809         return de;
1810
1811 journal_error:
1812         brelse(*bh);
1813         brelse(bh2);
1814         *bh = NULL;
1815         ext4_std_error(dir->i_sb, err);
1816         return ERR_PTR(err);
1817 }
1818
1819 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1820                       struct buffer_head *bh,
1821                       void *buf, int buf_size,
1822                       struct ext4_filename *fname,
1823                       struct ext4_dir_entry_2 **dest_de)
1824 {
1825         struct ext4_dir_entry_2 *de;
1826         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1827         int nlen, rlen;
1828         unsigned int offset = 0;
1829         char *top;
1830         int res;
1831
1832         de = (struct ext4_dir_entry_2 *)buf;
1833         top = buf + buf_size - reclen;
1834         while ((char *) de <= top) {
1835                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1836                                          buf, buf_size, offset)) {
1837                         res = -EFSCORRUPTED;
1838                         goto return_result;
1839                 }
1840                 /* Provide crypto context and crypto buffer to ext4 match */
1841                 res = ext4_match(fname, de);
1842                 if (res < 0)
1843                         goto return_result;
1844                 if (res > 0) {
1845                         res = -EEXIST;
1846                         goto return_result;
1847                 }
1848                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1849                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1850                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1851                         break;
1852                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1853                 offset += rlen;
1854         }
1855
1856         if ((char *) de > top)
1857                 res = -ENOSPC;
1858         else {
1859                 *dest_de = de;
1860                 res = 0;
1861         }
1862 return_result:
1863         return res;
1864 }
1865
1866 int ext4_insert_dentry(struct inode *dir,
1867                        struct inode *inode,
1868                        struct ext4_dir_entry_2 *de,
1869                        int buf_size,
1870                        struct ext4_filename *fname)
1871 {
1872
1873         int nlen, rlen;
1874
1875         nlen = EXT4_DIR_REC_LEN(de->name_len);
1876         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1877         if (de->inode) {
1878                 struct ext4_dir_entry_2 *de1 =
1879                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1880                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1881                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1882                 de = de1;
1883         }
1884         de->file_type = EXT4_FT_UNKNOWN;
1885         de->inode = cpu_to_le32(inode->i_ino);
1886         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1887         de->name_len = fname_len(fname);
1888         memcpy(de->name, fname_name(fname), fname_len(fname));
1889         return 0;
1890 }
1891
1892 /*
1893  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1894  * it points to a directory entry which is guaranteed to be large
1895  * enough for new directory entry.  If de is NULL, then
1896  * add_dirent_to_buf will attempt search the directory block for
1897  * space.  It will return -ENOSPC if no space is available, and -EIO
1898  * and -EEXIST if directory entry already exists.
1899  */
1900 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1901                              struct inode *dir,
1902                              struct inode *inode, struct ext4_dir_entry_2 *de,
1903                              struct buffer_head *bh)
1904 {
1905         unsigned int    blocksize = dir->i_sb->s_blocksize;
1906         int             csum_size = 0;
1907         int             err;
1908
1909         if (ext4_has_metadata_csum(inode->i_sb))
1910                 csum_size = sizeof(struct ext4_dir_entry_tail);
1911
1912         if (!de) {
1913                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1914                                         blocksize - csum_size, fname, &de);
1915                 if (err)
1916                         return err;
1917         }
1918         BUFFER_TRACE(bh, "get_write_access");
1919         err = ext4_journal_get_write_access(handle, bh);
1920         if (err) {
1921                 ext4_std_error(dir->i_sb, err);
1922                 return err;
1923         }
1924
1925         /* By now the buffer is marked for journaling. Due to crypto operations,
1926          * the following function call may fail */
1927         err = ext4_insert_dentry(dir, inode, de, blocksize, fname);
1928         if (err < 0)
1929                 return err;
1930
1931         /*
1932          * XXX shouldn't update any times until successful
1933          * completion of syscall, but too many callers depend
1934          * on this.
1935          *
1936          * XXX similarly, too many callers depend on
1937          * ext4_new_inode() setting the times, but error
1938          * recovery deletes the inode, so the worst that can
1939          * happen is that the times are slightly out of date
1940          * and/or different from the directory change time.
1941          */
1942         dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
1943         ext4_update_dx_flag(dir);
1944         dir->i_version++;
1945         ext4_mark_inode_dirty(handle, dir);
1946         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1947         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1948         if (err)
1949                 ext4_std_error(dir->i_sb, err);
1950         return 0;
1951 }
1952
1953 /*
1954  * This converts a one block unindexed directory to a 3 block indexed
1955  * directory, and adds the dentry to the indexed directory.
1956  */
1957 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1958                             struct inode *dir,
1959                             struct inode *inode, struct buffer_head *bh)
1960 {
1961         struct buffer_head *bh2;
1962         struct dx_root  *root;
1963         struct dx_frame frames[2], *frame;
1964         struct dx_entry *entries;
1965         struct ext4_dir_entry_2 *de, *de2;
1966         struct ext4_dir_entry_tail *t;
1967         char            *data1, *top;
1968         unsigned        len;
1969         int             retval;
1970         unsigned        blocksize;
1971         ext4_lblk_t  block;
1972         struct fake_dirent *fde;
1973         int csum_size = 0;
1974
1975         if (ext4_has_metadata_csum(inode->i_sb))
1976                 csum_size = sizeof(struct ext4_dir_entry_tail);
1977
1978         blocksize =  dir->i_sb->s_blocksize;
1979         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1980         BUFFER_TRACE(bh, "get_write_access");
1981         retval = ext4_journal_get_write_access(handle, bh);
1982         if (retval) {
1983                 ext4_std_error(dir->i_sb, retval);
1984                 brelse(bh);
1985                 return retval;
1986         }
1987         root = (struct dx_root *) bh->b_data;
1988
1989         /* The 0th block becomes the root, move the dirents out */
1990         fde = &root->dotdot;
1991         de = (struct ext4_dir_entry_2 *)((char *)fde +
1992                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1993         if ((char *) de >= (((char *) root) + blocksize)) {
1994                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1995                 brelse(bh);
1996                 return -EFSCORRUPTED;
1997         }
1998         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1999
2000         /* Allocate new block for the 0th block's dirents */
2001         bh2 = ext4_append(handle, dir, &block);
2002         if (IS_ERR(bh2)) {
2003                 brelse(bh);
2004                 return PTR_ERR(bh2);
2005         }
2006         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
2007         data1 = bh2->b_data;
2008
2009         memcpy (data1, de, len);
2010         de = (struct ext4_dir_entry_2 *) data1;
2011         top = data1 + len;
2012         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
2013                 de = de2;
2014         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
2015                                            (char *) de,
2016                                            blocksize);
2017
2018         if (csum_size) {
2019                 t = EXT4_DIRENT_TAIL(data1, blocksize);
2020                 initialize_dirent_tail(t, blocksize);
2021         }
2022
2023         /* Initialize the root; the dot dirents already exist */
2024         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
2025         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
2026                                            blocksize);
2027         memset (&root->info, 0, sizeof(root->info));
2028         root->info.info_length = sizeof(root->info);
2029         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
2030         entries = root->entries;
2031         dx_set_block(entries, 1);
2032         dx_set_count(entries, 1);
2033         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
2034
2035         /* Initialize as for dx_probe */
2036         fname->hinfo.hash_version = root->info.hash_version;
2037         if (fname->hinfo.hash_version <= DX_HASH_TEA)
2038                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
2039         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
2040         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
2041
2042         memset(frames, 0, sizeof(frames));
2043         frame = frames;
2044         frame->entries = entries;
2045         frame->at = entries;
2046         frame->bh = bh;
2047         bh = bh2;
2048
2049         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2050         if (retval)
2051                 goto out_frames;
2052         retval = ext4_handle_dirty_dirent_node(handle, dir, bh);
2053         if (retval)
2054                 goto out_frames;
2055
2056         de = do_split(handle,dir, &bh, frame, &fname->hinfo);
2057         if (IS_ERR(de)) {
2058                 retval = PTR_ERR(de);
2059                 goto out_frames;
2060         }
2061         dx_release(frames);
2062
2063         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2064         brelse(bh);
2065         return retval;
2066 out_frames:
2067         /*
2068          * Even if the block split failed, we have to properly write
2069          * out all the changes we did so far. Otherwise we can end up
2070          * with corrupted filesystem.
2071          */
2072         ext4_mark_inode_dirty(handle, dir);
2073         dx_release(frames);
2074         return retval;
2075 }
2076
2077 /*
2078  *      ext4_add_entry()
2079  *
2080  * adds a file entry to the specified directory, using the same
2081  * semantics as ext4_find_entry(). It returns NULL if it failed.
2082  *
2083  * NOTE!! The inode part of 'de' is left at 0 - which means you
2084  * may not sleep between calling this and putting something into
2085  * the entry, as someone else might have used it while you slept.
2086  */
2087 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2088                           struct inode *inode)
2089 {
2090         struct inode *dir = d_inode(dentry->d_parent);
2091         struct buffer_head *bh = NULL;
2092         struct ext4_dir_entry_2 *de;
2093         struct ext4_dir_entry_tail *t;
2094         struct super_block *sb;
2095         struct ext4_filename fname;
2096         int     retval;
2097         int     dx_fallback=0;
2098         unsigned blocksize;
2099         ext4_lblk_t block, blocks;
2100         int     csum_size = 0;
2101
2102         if (ext4_has_metadata_csum(inode->i_sb))
2103                 csum_size = sizeof(struct ext4_dir_entry_tail);
2104
2105         sb = dir->i_sb;
2106         blocksize = sb->s_blocksize;
2107         if (!dentry->d_name.len)
2108                 return -EINVAL;
2109
2110         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2111         if (retval)
2112                 return retval;
2113
2114         if (ext4_has_inline_data(dir)) {
2115                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2116                 if (retval < 0)
2117                         goto out;
2118                 if (retval == 1) {
2119                         retval = 0;
2120                         goto out;
2121                 }
2122         }
2123
2124         if (is_dx(dir)) {
2125                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2126                 if (!retval || (retval != ERR_BAD_DX_DIR))
2127                         goto out;
2128                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2129                 dx_fallback++;
2130                 ext4_mark_inode_dirty(handle, dir);
2131         }
2132         blocks = dir->i_size >> sb->s_blocksize_bits;
2133         for (block = 0; block < blocks; block++) {
2134                 bh = ext4_read_dirblock(dir, block, DIRENT);
2135                 if (IS_ERR(bh)) {
2136                         retval = PTR_ERR(bh);
2137                         bh = NULL;
2138                         goto out;
2139                 }
2140                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2141                                            NULL, bh);
2142                 if (retval != -ENOSPC)
2143                         goto out;
2144
2145                 if (blocks == 1 && !dx_fallback &&
2146                     ext4_has_feature_dir_index(sb)) {
2147                         retval = make_indexed_dir(handle, &fname, dir,
2148                                                   inode, bh);
2149                         bh = NULL; /* make_indexed_dir releases bh */
2150                         goto out;
2151                 }
2152                 brelse(bh);
2153         }
2154         bh = ext4_append(handle, dir, &block);
2155         if (IS_ERR(bh)) {
2156                 retval = PTR_ERR(bh);
2157                 bh = NULL;
2158                 goto out;
2159         }
2160         de = (struct ext4_dir_entry_2 *) bh->b_data;
2161         de->inode = 0;
2162         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2163
2164         if (csum_size) {
2165                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2166                 initialize_dirent_tail(t, blocksize);
2167         }
2168
2169         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2170 out:
2171         ext4_fname_free_filename(&fname);
2172         brelse(bh);
2173         if (retval == 0)
2174                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2175         return retval;
2176 }
2177
2178 /*
2179  * Returns 0 for success, or a negative error value
2180  */
2181 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2182                              struct inode *dir, struct inode *inode)
2183 {
2184         struct dx_frame frames[2], *frame;
2185         struct dx_entry *entries, *at;
2186         struct buffer_head *bh;
2187         struct super_block *sb = dir->i_sb;
2188         struct ext4_dir_entry_2 *de;
2189         int err;
2190
2191         frame = dx_probe(fname, dir, NULL, frames);
2192         if (IS_ERR(frame))
2193                 return PTR_ERR(frame);
2194         entries = frame->entries;
2195         at = frame->at;
2196         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2197         if (IS_ERR(bh)) {
2198                 err = PTR_ERR(bh);
2199                 bh = NULL;
2200                 goto cleanup;
2201         }
2202
2203         BUFFER_TRACE(bh, "get_write_access");
2204         err = ext4_journal_get_write_access(handle, bh);
2205         if (err)
2206                 goto journal_error;
2207
2208         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2209         if (err != -ENOSPC)
2210                 goto cleanup;
2211
2212         /* Block full, should compress but for now just split */
2213         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2214                        dx_get_count(entries), dx_get_limit(entries)));
2215         /* Need to split index? */
2216         if (dx_get_count(entries) == dx_get_limit(entries)) {
2217                 ext4_lblk_t newblock;
2218                 unsigned icount = dx_get_count(entries);
2219                 int levels = frame - frames;
2220                 struct dx_entry *entries2;
2221                 struct dx_node *node2;
2222                 struct buffer_head *bh2;
2223
2224                 if (levels && (dx_get_count(frames->entries) ==
2225                                dx_get_limit(frames->entries))) {
2226                         ext4_warning_inode(dir, "Directory index full!");
2227                         err = -ENOSPC;
2228                         goto cleanup;
2229                 }
2230                 bh2 = ext4_append(handle, dir, &newblock);
2231                 if (IS_ERR(bh2)) {
2232                         err = PTR_ERR(bh2);
2233                         goto cleanup;
2234                 }
2235                 node2 = (struct dx_node *)(bh2->b_data);
2236                 entries2 = node2->entries;
2237                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2238                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2239                                                            sb->s_blocksize);
2240                 BUFFER_TRACE(frame->bh, "get_write_access");
2241                 err = ext4_journal_get_write_access(handle, frame->bh);
2242                 if (err)
2243                         goto journal_error;
2244                 if (levels) {
2245                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2246                         unsigned hash2 = dx_get_hash(entries + icount1);
2247                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2248                                        icount1, icount2));
2249
2250                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2251                         err = ext4_journal_get_write_access(handle,
2252                                                              frames[0].bh);
2253                         if (err)
2254                                 goto journal_error;
2255
2256                         memcpy((char *) entries2, (char *) (entries + icount1),
2257                                icount2 * sizeof(struct dx_entry));
2258                         dx_set_count(entries, icount1);
2259                         dx_set_count(entries2, icount2);
2260                         dx_set_limit(entries2, dx_node_limit(dir));
2261
2262                         /* Which index block gets the new entry? */
2263                         if (at - entries >= icount1) {
2264                                 frame->at = at = at - entries - icount1 + entries2;
2265                                 frame->entries = entries = entries2;
2266                                 swap(frame->bh, bh2);
2267                         }
2268                         dx_insert_block(frames + 0, hash2, newblock);
2269                         dxtrace(dx_show_index("node", frames[1].entries));
2270                         dxtrace(dx_show_index("node",
2271                                ((struct dx_node *) bh2->b_data)->entries));
2272                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2273                         if (err)
2274                                 goto journal_error;
2275                         brelse (bh2);
2276                 } else {
2277                         dxtrace(printk(KERN_DEBUG
2278                                        "Creating second level index...\n"));
2279                         memcpy((char *) entries2, (char *) entries,
2280                                icount * sizeof(struct dx_entry));
2281                         dx_set_limit(entries2, dx_node_limit(dir));
2282
2283                         /* Set up root */
2284                         dx_set_count(entries, 1);
2285                         dx_set_block(entries + 0, newblock);
2286                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
2287
2288                         /* Add new access path frame */
2289                         frame = frames + 1;
2290                         frame->at = at = at - entries + entries2;
2291                         frame->entries = entries = entries2;
2292                         frame->bh = bh2;
2293                         err = ext4_journal_get_write_access(handle,
2294                                                              frame->bh);
2295                         if (err)
2296                                 goto journal_error;
2297                 }
2298                 err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
2299                 if (err) {
2300                         ext4_std_error(inode->i_sb, err);
2301                         goto cleanup;
2302                 }
2303         }
2304         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2305         if (IS_ERR(de)) {
2306                 err = PTR_ERR(de);
2307                 goto cleanup;
2308         }
2309         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2310         goto cleanup;
2311
2312 journal_error:
2313         ext4_std_error(dir->i_sb, err);
2314 cleanup:
2315         brelse(bh);
2316         dx_release(frames);
2317         return err;
2318 }
2319
2320 /*
2321  * ext4_generic_delete_entry deletes a directory entry by merging it
2322  * with the previous entry
2323  */
2324 int ext4_generic_delete_entry(handle_t *handle,
2325                               struct inode *dir,
2326                               struct ext4_dir_entry_2 *de_del,
2327                               struct buffer_head *bh,
2328                               void *entry_buf,
2329                               int buf_size,
2330                               int csum_size)
2331 {
2332         struct ext4_dir_entry_2 *de, *pde;
2333         unsigned int blocksize = dir->i_sb->s_blocksize;
2334         int i;
2335
2336         i = 0;
2337         pde = NULL;
2338         de = (struct ext4_dir_entry_2 *)entry_buf;
2339         while (i < buf_size - csum_size) {
2340                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2341                                          bh->b_data, bh->b_size, i))
2342                         return -EFSCORRUPTED;
2343                 if (de == de_del)  {
2344                         if (pde)
2345                                 pde->rec_len = ext4_rec_len_to_disk(
2346                                         ext4_rec_len_from_disk(pde->rec_len,
2347                                                                blocksize) +
2348                                         ext4_rec_len_from_disk(de->rec_len,
2349                                                                blocksize),
2350                                         blocksize);
2351                         else
2352                                 de->inode = 0;
2353                         dir->i_version++;
2354                         return 0;
2355                 }
2356                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2357                 pde = de;
2358                 de = ext4_next_entry(de, blocksize);
2359         }
2360         return -ENOENT;
2361 }
2362
2363 static int ext4_delete_entry(handle_t *handle,
2364                              struct inode *dir,
2365                              struct ext4_dir_entry_2 *de_del,
2366                              struct buffer_head *bh)
2367 {
2368         int err, csum_size = 0;
2369
2370         if (ext4_has_inline_data(dir)) {
2371                 int has_inline_data = 1;
2372                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2373                                                &has_inline_data);
2374                 if (has_inline_data)
2375                         return err;
2376         }
2377
2378         if (ext4_has_metadata_csum(dir->i_sb))
2379                 csum_size = sizeof(struct ext4_dir_entry_tail);
2380
2381         BUFFER_TRACE(bh, "get_write_access");
2382         err = ext4_journal_get_write_access(handle, bh);
2383         if (unlikely(err))
2384                 goto out;
2385
2386         err = ext4_generic_delete_entry(handle, dir, de_del,
2387                                         bh, bh->b_data,
2388                                         dir->i_sb->s_blocksize, csum_size);
2389         if (err)
2390                 goto out;
2391
2392         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2393         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2394         if (unlikely(err))
2395                 goto out;
2396
2397         return 0;
2398 out:
2399         if (err != -ENOENT)
2400                 ext4_std_error(dir->i_sb, err);
2401         return err;
2402 }
2403
2404 /*
2405  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
2406  * since this indicates that nlinks count was previously 1.
2407  */
2408 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2409 {
2410         inc_nlink(inode);
2411         if (is_dx(inode) && inode->i_nlink > 1) {
2412                 /* limit is 16-bit i_links_count */
2413                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
2414                         set_nlink(inode, 1);
2415                         ext4_set_feature_dir_nlink(inode->i_sb);
2416                 }
2417         }
2418 }
2419
2420 /*
2421  * If a directory had nlink == 1, then we should let it be 1. This indicates
2422  * directory has >EXT4_LINK_MAX subdirs.
2423  */
2424 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2425 {
2426         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2427                 drop_nlink(inode);
2428 }
2429
2430
2431 static int ext4_add_nondir(handle_t *handle,
2432                 struct dentry *dentry, struct inode *inode)
2433 {
2434         int err = ext4_add_entry(handle, dentry, inode);
2435         if (!err) {
2436                 ext4_mark_inode_dirty(handle, inode);
2437                 unlock_new_inode(inode);
2438                 d_instantiate(dentry, inode);
2439                 return 0;
2440         }
2441         drop_nlink(inode);
2442         unlock_new_inode(inode);
2443         iput(inode);
2444         return err;
2445 }
2446
2447 /*
2448  * By the time this is called, we already have created
2449  * the directory cache entry for the new file, but it
2450  * is so far negative - it has no inode.
2451  *
2452  * If the create succeeds, we fill in the inode information
2453  * with d_instantiate().
2454  */
2455 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2456                        bool excl)
2457 {
2458         handle_t *handle;
2459         struct inode *inode;
2460         int err, credits, retries = 0;
2461
2462         err = dquot_initialize(dir);
2463         if (err)
2464                 return err;
2465
2466         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2467                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2468 retry:
2469         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2470                                             NULL, EXT4_HT_DIR, credits);
2471         handle = ext4_journal_current_handle();
2472         err = PTR_ERR(inode);
2473         if (!IS_ERR(inode)) {
2474                 inode->i_op = &ext4_file_inode_operations;
2475                 inode->i_fop = &ext4_file_operations;
2476                 ext4_set_aops(inode);
2477                 err = ext4_add_nondir(handle, dentry, inode);
2478                 if (!err && IS_DIRSYNC(dir))
2479                         ext4_handle_sync(handle);
2480         }
2481         if (handle)
2482                 ext4_journal_stop(handle);
2483         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2484                 goto retry;
2485         return err;
2486 }
2487
2488 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2489                       umode_t mode, dev_t rdev)
2490 {
2491         handle_t *handle;
2492         struct inode *inode;
2493         int err, credits, retries = 0;
2494
2495         err = dquot_initialize(dir);
2496         if (err)
2497                 return err;
2498
2499         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2500                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2501 retry:
2502         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2503                                             NULL, EXT4_HT_DIR, credits);
2504         handle = ext4_journal_current_handle();
2505         err = PTR_ERR(inode);
2506         if (!IS_ERR(inode)) {
2507                 init_special_inode(inode, inode->i_mode, rdev);
2508                 inode->i_op = &ext4_special_inode_operations;
2509                 err = ext4_add_nondir(handle, dentry, inode);
2510                 if (!err && IS_DIRSYNC(dir))
2511                         ext4_handle_sync(handle);
2512         }
2513         if (handle)
2514                 ext4_journal_stop(handle);
2515         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2516                 goto retry;
2517         return err;
2518 }
2519
2520 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2521 {
2522         handle_t *handle;
2523         struct inode *inode;
2524         int err, retries = 0;
2525
2526         err = dquot_initialize(dir);
2527         if (err)
2528                 return err;
2529
2530 retry:
2531         inode = ext4_new_inode_start_handle(dir, mode,
2532                                             NULL, 0, NULL,
2533                                             EXT4_HT_DIR,
2534                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2535                           4 + EXT4_XATTR_TRANS_BLOCKS);
2536         handle = ext4_journal_current_handle();
2537         err = PTR_ERR(inode);
2538         if (!IS_ERR(inode)) {
2539                 inode->i_op = &ext4_file_inode_operations;
2540                 inode->i_fop = &ext4_file_operations;
2541                 ext4_set_aops(inode);
2542                 d_tmpfile(dentry, inode);
2543                 err = ext4_orphan_add(handle, inode);
2544                 if (err)
2545                         goto err_unlock_inode;
2546                 mark_inode_dirty(inode);
2547                 unlock_new_inode(inode);
2548         }
2549         if (handle)
2550                 ext4_journal_stop(handle);
2551         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2552                 goto retry;
2553         return err;
2554 err_unlock_inode:
2555         ext4_journal_stop(handle);
2556         unlock_new_inode(inode);
2557         return err;
2558 }
2559
2560 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2561                           struct ext4_dir_entry_2 *de,
2562                           int blocksize, int csum_size,
2563                           unsigned int parent_ino, int dotdot_real_len)
2564 {
2565         de->inode = cpu_to_le32(inode->i_ino);
2566         de->name_len = 1;
2567         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2568                                            blocksize);
2569         strcpy(de->name, ".");
2570         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2571
2572         de = ext4_next_entry(de, blocksize);
2573         de->inode = cpu_to_le32(parent_ino);
2574         de->name_len = 2;
2575         if (!dotdot_real_len)
2576                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2577                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2578                                         blocksize);
2579         else
2580                 de->rec_len = ext4_rec_len_to_disk(
2581                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2582         strcpy(de->name, "..");
2583         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2584
2585         return ext4_next_entry(de, blocksize);
2586 }
2587
2588 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2589                              struct inode *inode)
2590 {
2591         struct buffer_head *dir_block = NULL;
2592         struct ext4_dir_entry_2 *de;
2593         struct ext4_dir_entry_tail *t;
2594         ext4_lblk_t block = 0;
2595         unsigned int blocksize = dir->i_sb->s_blocksize;
2596         int csum_size = 0;
2597         int err;
2598
2599         if (ext4_has_metadata_csum(dir->i_sb))
2600                 csum_size = sizeof(struct ext4_dir_entry_tail);
2601
2602         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2603                 err = ext4_try_create_inline_dir(handle, dir, inode);
2604                 if (err < 0 && err != -ENOSPC)
2605                         goto out;
2606                 if (!err)
2607                         goto out;
2608         }
2609
2610         inode->i_size = 0;
2611         dir_block = ext4_append(handle, inode, &block);
2612         if (IS_ERR(dir_block))
2613                 return PTR_ERR(dir_block);
2614         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2615         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2616         set_nlink(inode, 2);
2617         if (csum_size) {
2618                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2619                 initialize_dirent_tail(t, blocksize);
2620         }
2621
2622         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2623         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2624         if (err)
2625                 goto out;
2626         set_buffer_verified(dir_block);
2627 out:
2628         brelse(dir_block);
2629         return err;
2630 }
2631
2632 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2633 {
2634         handle_t *handle;
2635         struct inode *inode;
2636         int err, credits, retries = 0;
2637
2638         if (EXT4_DIR_LINK_MAX(dir))
2639                 return -EMLINK;
2640
2641         err = dquot_initialize(dir);
2642         if (err)
2643                 return err;
2644
2645         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2646                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2647 retry:
2648         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2649                                             &dentry->d_name,
2650                                             0, NULL, EXT4_HT_DIR, credits);
2651         handle = ext4_journal_current_handle();
2652         err = PTR_ERR(inode);
2653         if (IS_ERR(inode))
2654                 goto out_stop;
2655
2656         inode->i_op = &ext4_dir_inode_operations;
2657         inode->i_fop = &ext4_dir_operations;
2658         err = ext4_init_new_dir(handle, dir, inode);
2659         if (err)
2660                 goto out_clear_inode;
2661         err = ext4_mark_inode_dirty(handle, inode);
2662         if (!err)
2663                 err = ext4_add_entry(handle, dentry, inode);
2664         if (err) {
2665 out_clear_inode:
2666                 clear_nlink(inode);
2667                 unlock_new_inode(inode);
2668                 ext4_mark_inode_dirty(handle, inode);
2669                 iput(inode);
2670                 goto out_stop;
2671         }
2672         ext4_inc_count(handle, dir);
2673         ext4_update_dx_flag(dir);
2674         err = ext4_mark_inode_dirty(handle, dir);
2675         if (err)
2676                 goto out_clear_inode;
2677         unlock_new_inode(inode);
2678         d_instantiate(dentry, inode);
2679         if (IS_DIRSYNC(dir))
2680                 ext4_handle_sync(handle);
2681
2682 out_stop:
2683         if (handle)
2684                 ext4_journal_stop(handle);
2685         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2686                 goto retry;
2687         return err;
2688 }
2689
2690 /*
2691  * routine to check that the specified directory is empty (for rmdir)
2692  */
2693 bool ext4_empty_dir(struct inode *inode)
2694 {
2695         unsigned int offset;
2696         struct buffer_head *bh;
2697         struct ext4_dir_entry_2 *de, *de1;
2698         struct super_block *sb;
2699
2700         if (ext4_has_inline_data(inode)) {
2701                 int has_inline_data = 1;
2702                 int ret;
2703
2704                 ret = empty_inline_dir(inode, &has_inline_data);
2705                 if (has_inline_data)
2706                         return ret;
2707         }
2708
2709         sb = inode->i_sb;
2710         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2711                 EXT4_ERROR_INODE(inode, "invalid size");
2712                 return true;
2713         }
2714         bh = ext4_read_dirblock(inode, 0, EITHER);
2715         if (IS_ERR(bh))
2716                 return true;
2717
2718         de = (struct ext4_dir_entry_2 *) bh->b_data;
2719         de1 = ext4_next_entry(de, sb->s_blocksize);
2720         if (le32_to_cpu(de->inode) != inode->i_ino ||
2721                         le32_to_cpu(de1->inode) == 0 ||
2722                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2723                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2724                 brelse(bh);
2725                 return true;
2726         }
2727         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2728                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2729         de = ext4_next_entry(de1, sb->s_blocksize);
2730         while (offset < inode->i_size) {
2731                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2732                         unsigned int lblock;
2733                         brelse(bh);
2734                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2735                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2736                         if (IS_ERR(bh))
2737                                 return true;
2738                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2739                 }
2740                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2741                                          bh->b_data, bh->b_size, offset)) {
2742                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2743                                                          sb->s_blocksize);
2744                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2745                         continue;
2746                 }
2747                 if (le32_to_cpu(de->inode)) {
2748                         brelse(bh);
2749                         return false;
2750                 }
2751                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2752                 de = ext4_next_entry(de, sb->s_blocksize);
2753         }
2754         brelse(bh);
2755         return true;
2756 }
2757
2758 /*
2759  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2760  * such inodes, starting at the superblock, in case we crash before the
2761  * file is closed/deleted, or in case the inode truncate spans multiple
2762  * transactions and the last transaction is not recovered after a crash.
2763  *
2764  * At filesystem recovery time, we walk this list deleting unlinked
2765  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2766  *
2767  * Orphan list manipulation functions must be called under i_mutex unless
2768  * we are just creating the inode or deleting it.
2769  */
2770 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2771 {
2772         struct super_block *sb = inode->i_sb;
2773         struct ext4_sb_info *sbi = EXT4_SB(sb);
2774         struct ext4_iloc iloc;
2775         int err = 0, rc;
2776         bool dirty = false;
2777
2778         if (!sbi->s_journal || is_bad_inode(inode))
2779                 return 0;
2780
2781         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2782                      !inode_is_locked(inode));
2783         /*
2784          * Exit early if inode already is on orphan list. This is a big speedup
2785          * since we don't have to contend on the global s_orphan_lock.
2786          */
2787         if (!list_empty(&EXT4_I(inode)->i_orphan))
2788                 return 0;
2789
2790         /*
2791          * Orphan handling is only valid for files with data blocks
2792          * being truncated, or files being unlinked. Note that we either
2793          * hold i_mutex, or the inode can not be referenced from outside,
2794          * so i_nlink should not be bumped due to race
2795          */
2796         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2797                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2798
2799         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2800         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2801         if (err)
2802                 goto out;
2803
2804         err = ext4_reserve_inode_write(handle, inode, &iloc);
2805         if (err)
2806                 goto out;
2807
2808         mutex_lock(&sbi->s_orphan_lock);
2809         /*
2810          * Due to previous errors inode may be already a part of on-disk
2811          * orphan list. If so skip on-disk list modification.
2812          */
2813         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2814             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2815                 /* Insert this inode at the head of the on-disk orphan list */
2816                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2817                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2818                 dirty = true;
2819         }
2820         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2821         mutex_unlock(&sbi->s_orphan_lock);
2822
2823         if (dirty) {
2824                 err = ext4_handle_dirty_super(handle, sb);
2825                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2826                 if (!err)
2827                         err = rc;
2828                 if (err) {
2829                         /*
2830                          * We have to remove inode from in-memory list if
2831                          * addition to on disk orphan list failed. Stray orphan
2832                          * list entries can cause panics at unmount time.
2833                          */
2834                         mutex_lock(&sbi->s_orphan_lock);
2835                         list_del_init(&EXT4_I(inode)->i_orphan);
2836                         mutex_unlock(&sbi->s_orphan_lock);
2837                 }
2838         }
2839         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2840         jbd_debug(4, "orphan inode %lu will point to %d\n",
2841                         inode->i_ino, NEXT_ORPHAN(inode));
2842 out:
2843         ext4_std_error(sb, err);
2844         return err;
2845 }
2846
2847 /*
2848  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2849  * of such inodes stored on disk, because it is finally being cleaned up.
2850  */
2851 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2852 {
2853         struct list_head *prev;
2854         struct ext4_inode_info *ei = EXT4_I(inode);
2855         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2856         __u32 ino_next;
2857         struct ext4_iloc iloc;
2858         int err = 0;
2859
2860         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2861                 return 0;
2862
2863         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2864                      !inode_is_locked(inode));
2865         /* Do this quick check before taking global s_orphan_lock. */
2866         if (list_empty(&ei->i_orphan))
2867                 return 0;
2868
2869         if (handle) {
2870                 /* Grab inode buffer early before taking global s_orphan_lock */
2871                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2872         }
2873
2874         mutex_lock(&sbi->s_orphan_lock);
2875         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2876
2877         prev = ei->i_orphan.prev;
2878         list_del_init(&ei->i_orphan);
2879
2880         /* If we're on an error path, we may not have a valid
2881          * transaction handle with which to update the orphan list on
2882          * disk, but we still need to remove the inode from the linked
2883          * list in memory. */
2884         if (!handle || err) {
2885                 mutex_unlock(&sbi->s_orphan_lock);
2886                 goto out_err;
2887         }
2888
2889         ino_next = NEXT_ORPHAN(inode);
2890         if (prev == &sbi->s_orphan) {
2891                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2892                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2893                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2894                 if (err) {
2895                         mutex_unlock(&sbi->s_orphan_lock);
2896                         goto out_brelse;
2897                 }
2898                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2899                 mutex_unlock(&sbi->s_orphan_lock);
2900                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2901         } else {
2902                 struct ext4_iloc iloc2;
2903                 struct inode *i_prev =
2904                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2905
2906                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2907                           i_prev->i_ino, ino_next);
2908                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2909                 if (err) {
2910                         mutex_unlock(&sbi->s_orphan_lock);
2911                         goto out_brelse;
2912                 }
2913                 NEXT_ORPHAN(i_prev) = ino_next;
2914                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2915                 mutex_unlock(&sbi->s_orphan_lock);
2916         }
2917         if (err)
2918                 goto out_brelse;
2919         NEXT_ORPHAN(inode) = 0;
2920         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2921 out_err:
2922         ext4_std_error(inode->i_sb, err);
2923         return err;
2924
2925 out_brelse:
2926         brelse(iloc.bh);
2927         goto out_err;
2928 }
2929
2930 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2931 {
2932         int retval;
2933         struct inode *inode;
2934         struct buffer_head *bh;
2935         struct ext4_dir_entry_2 *de;
2936         handle_t *handle = NULL;
2937
2938         /* Initialize quotas before so that eventual writes go in
2939          * separate transaction */
2940         retval = dquot_initialize(dir);
2941         if (retval)
2942                 return retval;
2943         retval = dquot_initialize(d_inode(dentry));
2944         if (retval)
2945                 return retval;
2946
2947         retval = -ENOENT;
2948         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2949         if (IS_ERR(bh))
2950                 return PTR_ERR(bh);
2951         if (!bh)
2952                 goto end_rmdir;
2953
2954         inode = d_inode(dentry);
2955
2956         retval = -EFSCORRUPTED;
2957         if (le32_to_cpu(de->inode) != inode->i_ino)
2958                 goto end_rmdir;
2959
2960         retval = -ENOTEMPTY;
2961         if (!ext4_empty_dir(inode))
2962                 goto end_rmdir;
2963
2964         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2965                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2966         if (IS_ERR(handle)) {
2967                 retval = PTR_ERR(handle);
2968                 handle = NULL;
2969                 goto end_rmdir;
2970         }
2971
2972         if (IS_DIRSYNC(dir))
2973                 ext4_handle_sync(handle);
2974
2975         retval = ext4_delete_entry(handle, dir, de, bh);
2976         if (retval)
2977                 goto end_rmdir;
2978         if (!EXT4_DIR_LINK_EMPTY(inode))
2979                 ext4_warning_inode(inode,
2980                              "empty directory '%.*s' has too many links (%u)",
2981                              dentry->d_name.len, dentry->d_name.name,
2982                              inode->i_nlink);
2983         inode->i_version++;
2984         clear_nlink(inode);
2985         /* There's no need to set i_disksize: the fact that i_nlink is
2986          * zero will ensure that the right thing happens during any
2987          * recovery. */
2988         inode->i_size = 0;
2989         ext4_orphan_add(handle, inode);
2990         inode->i_ctime = dir->i_ctime = dir->i_mtime = ext4_current_time(inode);
2991         ext4_mark_inode_dirty(handle, inode);
2992         ext4_dec_count(handle, dir);
2993         ext4_update_dx_flag(dir);
2994         ext4_mark_inode_dirty(handle, dir);
2995
2996 end_rmdir:
2997         brelse(bh);
2998         if (handle)
2999                 ext4_journal_stop(handle);
3000         return retval;
3001 }
3002
3003 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
3004 {
3005         int retval;
3006         struct inode *inode;
3007         struct buffer_head *bh;
3008         struct ext4_dir_entry_2 *de;
3009         handle_t *handle = NULL;
3010
3011         trace_ext4_unlink_enter(dir, dentry);
3012         /* Initialize quotas before so that eventual writes go
3013          * in separate transaction */
3014         retval = dquot_initialize(dir);
3015         if (retval)
3016                 return retval;
3017         retval = dquot_initialize(d_inode(dentry));
3018         if (retval)
3019                 return retval;
3020
3021         retval = -ENOENT;
3022         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3023         if (IS_ERR(bh))
3024                 return PTR_ERR(bh);
3025         if (!bh)
3026                 goto end_unlink;
3027
3028         inode = d_inode(dentry);
3029
3030         retval = -EFSCORRUPTED;
3031         if (le32_to_cpu(de->inode) != inode->i_ino)
3032                 goto end_unlink;
3033
3034         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3035                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3036         if (IS_ERR(handle)) {
3037                 retval = PTR_ERR(handle);
3038                 handle = NULL;
3039                 goto end_unlink;
3040         }
3041
3042         if (IS_DIRSYNC(dir))
3043                 ext4_handle_sync(handle);
3044
3045         if (inode->i_nlink == 0) {
3046                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3047                                    dentry->d_name.len, dentry->d_name.name);
3048                 set_nlink(inode, 1);
3049         }
3050         retval = ext4_delete_entry(handle, dir, de, bh);
3051         if (retval)
3052                 goto end_unlink;
3053         dir->i_ctime = dir->i_mtime = ext4_current_time(dir);
3054         ext4_update_dx_flag(dir);
3055         ext4_mark_inode_dirty(handle, dir);
3056         drop_nlink(inode);
3057         if (!inode->i_nlink)
3058                 ext4_orphan_add(handle, inode);
3059         inode->i_ctime = ext4_current_time(inode);
3060         ext4_mark_inode_dirty(handle, inode);
3061
3062 end_unlink:
3063         brelse(bh);
3064         if (handle)
3065                 ext4_journal_stop(handle);
3066         trace_ext4_unlink_exit(dentry, retval);
3067         return retval;
3068 }
3069
3070 static int ext4_symlink(struct inode *dir,
3071                         struct dentry *dentry, const char *symname)
3072 {
3073         handle_t *handle;
3074         struct inode *inode;
3075         int err, len = strlen(symname);
3076         int credits;
3077         bool encryption_required;
3078         struct fscrypt_str disk_link;
3079         struct fscrypt_symlink_data *sd = NULL;
3080
3081         disk_link.len = len + 1;
3082         disk_link.name = (char *) symname;
3083
3084         encryption_required = (ext4_encrypted_inode(dir) ||
3085                                DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
3086         if (encryption_required) {
3087                 err = fscrypt_get_encryption_info(dir);
3088                 if (err)
3089                         return err;
3090                 if (!fscrypt_has_encryption_key(dir))
3091                         return -EPERM;
3092                 disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
3093                                  sizeof(struct fscrypt_symlink_data));
3094                 sd = kzalloc(disk_link.len, GFP_KERNEL);
3095                 if (!sd)
3096                         return -ENOMEM;
3097         }
3098
3099         if (disk_link.len > dir->i_sb->s_blocksize) {
3100                 err = -ENAMETOOLONG;
3101                 goto err_free_sd;
3102         }
3103
3104         err = dquot_initialize(dir);
3105         if (err)
3106                 goto err_free_sd;
3107
3108         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3109                 /*
3110                  * For non-fast symlinks, we just allocate inode and put it on
3111                  * orphan list in the first transaction => we need bitmap,
3112                  * group descriptor, sb, inode block, quota blocks, and
3113                  * possibly selinux xattr blocks.
3114                  */
3115                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3116                           EXT4_XATTR_TRANS_BLOCKS;
3117         } else {
3118                 /*
3119                  * Fast symlink. We have to add entry to directory
3120                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3121                  * allocate new inode (bitmap, group descriptor, inode block,
3122                  * quota blocks, sb is already counted in previous macros).
3123                  */
3124                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3125                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3126         }
3127
3128         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3129                                             &dentry->d_name, 0, NULL,
3130                                             EXT4_HT_DIR, credits);
3131         handle = ext4_journal_current_handle();
3132         if (IS_ERR(inode)) {
3133                 if (handle)
3134                         ext4_journal_stop(handle);
3135                 err = PTR_ERR(inode);
3136                 goto err_free_sd;
3137         }
3138
3139         if (encryption_required) {
3140                 struct qstr istr;
3141                 struct fscrypt_str ostr =
3142                         FSTR_INIT(sd->encrypted_path, disk_link.len);
3143
3144                 istr.name = (const unsigned char *) symname;
3145                 istr.len = len;
3146                 err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
3147                 if (err < 0)
3148                         goto err_drop_inode;
3149                 sd->len = cpu_to_le16(ostr.len);
3150                 disk_link.name = (char *) sd;
3151                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3152         }
3153
3154         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3155                 if (!encryption_required)
3156                         inode->i_op = &ext4_symlink_inode_operations;
3157                 inode_nohighmem(inode);
3158                 ext4_set_aops(inode);
3159                 /*
3160                  * We cannot call page_symlink() with transaction started
3161                  * because it calls into ext4_write_begin() which can wait
3162                  * for transaction commit if we are running out of space
3163                  * and thus we deadlock. So we have to stop transaction now
3164                  * and restart it when symlink contents is written.
3165                  *
3166                  * To keep fs consistent in case of crash, we have to put inode
3167                  * to orphan list in the mean time.
3168                  */
3169                 drop_nlink(inode);
3170                 err = ext4_orphan_add(handle, inode);
3171                 ext4_journal_stop(handle);
3172                 handle = NULL;
3173                 if (err)
3174                         goto err_drop_inode;
3175                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3176                 if (err)
3177                         goto err_drop_inode;
3178                 /*
3179                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3180                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3181                  */
3182                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3183                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3184                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3185                 if (IS_ERR(handle)) {
3186                         err = PTR_ERR(handle);
3187                         handle = NULL;
3188                         goto err_drop_inode;
3189                 }
3190                 set_nlink(inode, 1);
3191                 err = ext4_orphan_del(handle, inode);
3192                 if (err)
3193                         goto err_drop_inode;
3194         } else {
3195                 /* clear the extent format for fast symlink */
3196                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3197                 if (!encryption_required) {
3198                         inode->i_op = &ext4_fast_symlink_inode_operations;
3199                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3200                 }
3201                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3202                        disk_link.len);
3203                 inode->i_size = disk_link.len - 1;
3204         }
3205         EXT4_I(inode)->i_disksize = inode->i_size;
3206         err = ext4_add_nondir(handle, dentry, inode);
3207         if (!err && IS_DIRSYNC(dir))
3208                 ext4_handle_sync(handle);
3209
3210         if (handle)
3211                 ext4_journal_stop(handle);
3212         kfree(sd);
3213         return err;
3214 err_drop_inode:
3215         if (handle)
3216                 ext4_journal_stop(handle);
3217         clear_nlink(inode);
3218         unlock_new_inode(inode);
3219         iput(inode);
3220 err_free_sd:
3221         kfree(sd);
3222         return err;
3223 }
3224
3225 static int ext4_link(struct dentry *old_dentry,
3226                      struct inode *dir, struct dentry *dentry)
3227 {
3228         handle_t *handle;
3229         struct inode *inode = d_inode(old_dentry);
3230         int err, retries = 0;
3231
3232         if (inode->i_nlink >= EXT4_LINK_MAX)
3233                 return -EMLINK;
3234         if (ext4_encrypted_inode(dir) &&
3235                         !fscrypt_has_permitted_context(dir, inode))
3236                 return -EPERM;
3237
3238        if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3239            (!projid_eq(EXT4_I(dir)->i_projid,
3240                        EXT4_I(old_dentry->d_inode)->i_projid)))
3241                 return -EXDEV;
3242
3243         err = dquot_initialize(dir);
3244         if (err)
3245                 return err;
3246
3247 retry:
3248         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3249                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3250                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3251         if (IS_ERR(handle))
3252                 return PTR_ERR(handle);
3253
3254         if (IS_DIRSYNC(dir))
3255                 ext4_handle_sync(handle);
3256
3257         inode->i_ctime = ext4_current_time(inode);
3258         ext4_inc_count(handle, inode);
3259         ihold(inode);
3260
3261         err = ext4_add_entry(handle, dentry, inode);
3262         if (!err) {
3263                 ext4_mark_inode_dirty(handle, inode);
3264                 /* this can happen only for tmpfile being
3265                  * linked the first time
3266                  */
3267                 if (inode->i_nlink == 1)
3268                         ext4_orphan_del(handle, inode);
3269                 d_instantiate(dentry, inode);
3270         } else {
3271                 drop_nlink(inode);
3272                 iput(inode);
3273         }
3274         ext4_journal_stop(handle);
3275         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3276                 goto retry;
3277         return err;
3278 }
3279
3280
3281 /*
3282  * Try to find buffer head where contains the parent block.
3283  * It should be the inode block if it is inlined or the 1st block
3284  * if it is a normal dir.
3285  */
3286 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3287                                         struct inode *inode,
3288                                         int *retval,
3289                                         struct ext4_dir_entry_2 **parent_de,
3290                                         int *inlined)
3291 {
3292         struct buffer_head *bh;
3293
3294         if (!ext4_has_inline_data(inode)) {
3295                 bh = ext4_read_dirblock(inode, 0, EITHER);
3296                 if (IS_ERR(bh)) {
3297                         *retval = PTR_ERR(bh);
3298                         return NULL;
3299                 }
3300                 *parent_de = ext4_next_entry(
3301                                         (struct ext4_dir_entry_2 *)bh->b_data,
3302                                         inode->i_sb->s_blocksize);
3303                 return bh;
3304         }
3305
3306         *inlined = 1;
3307         return ext4_get_first_inline_block(inode, parent_de, retval);
3308 }
3309
3310 struct ext4_renament {
3311         struct inode *dir;
3312         struct dentry *dentry;
3313         struct inode *inode;
3314         bool is_dir;
3315         int dir_nlink_delta;
3316
3317         /* entry for "dentry" */
3318         struct buffer_head *bh;
3319         struct ext4_dir_entry_2 *de;
3320         int inlined;
3321
3322         /* entry for ".." in inode if it's a directory */
3323         struct buffer_head *dir_bh;
3324         struct ext4_dir_entry_2 *parent_de;
3325         int dir_inlined;
3326 };
3327
3328 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3329 {
3330         int retval;
3331
3332         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3333                                               &retval, &ent->parent_de,
3334                                               &ent->dir_inlined);
3335         if (!ent->dir_bh)
3336                 return retval;
3337         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3338                 return -EFSCORRUPTED;
3339         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3340         return ext4_journal_get_write_access(handle, ent->dir_bh);
3341 }
3342
3343 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3344                                   unsigned dir_ino)
3345 {
3346         int retval;
3347
3348         ent->parent_de->inode = cpu_to_le32(dir_ino);
3349         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3350         if (!ent->dir_inlined) {
3351                 if (is_dx(ent->inode)) {
3352                         retval = ext4_handle_dirty_dx_node(handle,
3353                                                            ent->inode,
3354                                                            ent->dir_bh);
3355                 } else {
3356                         retval = ext4_handle_dirty_dirent_node(handle,
3357                                                                ent->inode,
3358                                                                ent->dir_bh);
3359                 }
3360         } else {
3361                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3362         }
3363         if (retval) {
3364                 ext4_std_error(ent->dir->i_sb, retval);
3365                 return retval;
3366         }
3367         return 0;
3368 }
3369
3370 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3371                        unsigned ino, unsigned file_type)
3372 {
3373         int retval;
3374
3375         BUFFER_TRACE(ent->bh, "get write access");
3376         retval = ext4_journal_get_write_access(handle, ent->bh);
3377         if (retval)
3378                 return retval;
3379         ent->de->inode = cpu_to_le32(ino);
3380         if (ext4_has_feature_filetype(ent->dir->i_sb))
3381                 ent->de->file_type = file_type;
3382         ent->dir->i_version++;
3383         ent->dir->i_ctime = ent->dir->i_mtime =
3384                 ext4_current_time(ent->dir);
3385         ext4_mark_inode_dirty(handle, ent->dir);
3386         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3387         if (!ent->inlined) {
3388                 retval = ext4_handle_dirty_dirent_node(handle,
3389                                                        ent->dir, ent->bh);
3390                 if (unlikely(retval)) {
3391                         ext4_std_error(ent->dir->i_sb, retval);
3392                         return retval;
3393                 }
3394         }
3395         brelse(ent->bh);
3396         ent->bh = NULL;
3397
3398         return 0;
3399 }
3400
3401 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3402                                   const struct qstr *d_name)
3403 {
3404         int retval = -ENOENT;
3405         struct buffer_head *bh;
3406         struct ext4_dir_entry_2 *de;
3407
3408         bh = ext4_find_entry(dir, d_name, &de, NULL);
3409         if (IS_ERR(bh))
3410                 return PTR_ERR(bh);
3411         if (bh) {
3412                 retval = ext4_delete_entry(handle, dir, de, bh);
3413                 brelse(bh);
3414         }
3415         return retval;
3416 }
3417
3418 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3419                                int force_reread)
3420 {
3421         int retval;
3422         /*
3423          * ent->de could have moved from under us during htree split, so make
3424          * sure that we are deleting the right entry.  We might also be pointing
3425          * to a stale entry in the unused part of ent->bh so just checking inum
3426          * and the name isn't enough.
3427          */
3428         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3429             ent->de->name_len != ent->dentry->d_name.len ||
3430             strncmp(ent->de->name, ent->dentry->d_name.name,
3431                     ent->de->name_len) ||
3432             force_reread) {
3433                 retval = ext4_find_delete_entry(handle, ent->dir,
3434                                                 &ent->dentry->d_name);
3435         } else {
3436                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3437                 if (retval == -ENOENT) {
3438                         retval = ext4_find_delete_entry(handle, ent->dir,
3439                                                         &ent->dentry->d_name);
3440                 }
3441         }
3442
3443         if (retval) {
3444                 ext4_warning_inode(ent->dir,
3445                                    "Deleting old file: nlink %d, error=%d",
3446                                    ent->dir->i_nlink, retval);
3447         }
3448 }
3449
3450 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3451 {
3452         if (ent->dir_nlink_delta) {
3453                 if (ent->dir_nlink_delta == -1)
3454                         ext4_dec_count(handle, ent->dir);
3455                 else
3456                         ext4_inc_count(handle, ent->dir);
3457                 ext4_mark_inode_dirty(handle, ent->dir);
3458         }
3459 }
3460
3461 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3462                                               int credits, handle_t **h)
3463 {
3464         struct inode *wh;
3465         handle_t *handle;
3466         int retries = 0;
3467
3468         /*
3469          * for inode block, sb block, group summaries,
3470          * and inode bitmap
3471          */
3472         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3473                     EXT4_XATTR_TRANS_BLOCKS + 4);
3474 retry:
3475         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3476                                          &ent->dentry->d_name, 0, NULL,
3477                                          EXT4_HT_DIR, credits);
3478
3479         handle = ext4_journal_current_handle();
3480         if (IS_ERR(wh)) {
3481                 if (handle)
3482                         ext4_journal_stop(handle);
3483                 if (PTR_ERR(wh) == -ENOSPC &&
3484                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3485                         goto retry;
3486         } else {
3487                 *h = handle;
3488                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3489                 wh->i_op = &ext4_special_inode_operations;
3490         }
3491         return wh;
3492 }
3493
3494 /*
3495  * Anybody can rename anything with this: the permission checks are left to the
3496  * higher-level routines.
3497  *
3498  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3499  * while new_{dentry,inode) refers to the destination dentry/inode
3500  * This comes from rename(const char *oldpath, const char *newpath)
3501  */
3502 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3503                        struct inode *new_dir, struct dentry *new_dentry,
3504                        unsigned int flags)
3505 {
3506         handle_t *handle = NULL;
3507         struct ext4_renament old = {
3508                 .dir = old_dir,
3509                 .dentry = old_dentry,
3510                 .inode = d_inode(old_dentry),
3511         };
3512         struct ext4_renament new = {
3513                 .dir = new_dir,
3514                 .dentry = new_dentry,
3515                 .inode = d_inode(new_dentry),
3516         };
3517         int force_reread;
3518         int retval;
3519         struct inode *whiteout = NULL;
3520         int credits;
3521         u8 old_file_type;
3522
3523         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3524             (!projid_eq(EXT4_I(new_dir)->i_projid,
3525                         EXT4_I(old_dentry->d_inode)->i_projid)))
3526                 return -EXDEV;
3527
3528         retval = dquot_initialize(old.dir);
3529         if (retval)
3530                 return retval;
3531         retval = dquot_initialize(new.dir);
3532         if (retval)
3533                 return retval;
3534
3535         /* Initialize quotas before so that eventual writes go
3536          * in separate transaction */
3537         if (new.inode) {
3538                 retval = dquot_initialize(new.inode);
3539                 if (retval)
3540                         return retval;
3541         }
3542
3543         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3544         if (IS_ERR(old.bh))
3545                 return PTR_ERR(old.bh);
3546         /*
3547          *  Check for inode number is _not_ due to possible IO errors.
3548          *  We might rmdir the source, keep it as pwd of some process
3549          *  and merrily kill the link to whatever was created under the
3550          *  same name. Goodbye sticky bit ;-<
3551          */
3552         retval = -ENOENT;
3553         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3554                 goto end_rename;
3555
3556         if ((old.dir != new.dir) &&
3557             ext4_encrypted_inode(new.dir) &&
3558             !fscrypt_has_permitted_context(new.dir, old.inode)) {
3559                 retval = -EPERM;
3560                 goto end_rename;
3561         }
3562
3563         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3564                                  &new.de, &new.inlined);
3565         if (IS_ERR(new.bh)) {
3566                 retval = PTR_ERR(new.bh);
3567                 new.bh = NULL;
3568                 goto end_rename;
3569         }
3570         if (new.bh) {
3571                 if (!new.inode) {
3572                         brelse(new.bh);
3573                         new.bh = NULL;
3574                 }
3575         }
3576         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3577                 ext4_alloc_da_blocks(old.inode);
3578
3579         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3580                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3581         if (!(flags & RENAME_WHITEOUT)) {
3582                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3583                 if (IS_ERR(handle)) {
3584                         retval = PTR_ERR(handle);
3585                         handle = NULL;
3586                         goto end_rename;
3587                 }
3588         } else {
3589                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3590                 if (IS_ERR(whiteout)) {
3591                         retval = PTR_ERR(whiteout);
3592                         whiteout = NULL;
3593                         goto end_rename;
3594                 }
3595         }
3596
3597         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3598                 ext4_handle_sync(handle);
3599
3600         if (S_ISDIR(old.inode->i_mode)) {
3601                 if (new.inode) {
3602                         retval = -ENOTEMPTY;
3603                         if (!ext4_empty_dir(new.inode))
3604                                 goto end_rename;
3605                 } else {
3606                         retval = -EMLINK;
3607                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3608                                 goto end_rename;
3609                 }
3610                 retval = ext4_rename_dir_prepare(handle, &old);
3611                 if (retval)
3612                         goto end_rename;
3613         }
3614         /*
3615          * If we're renaming a file within an inline_data dir and adding or
3616          * setting the new dirent causes a conversion from inline_data to
3617          * extents/blockmap, we need to force the dirent delete code to
3618          * re-read the directory, or else we end up trying to delete a dirent
3619          * from what is now the extent tree root (or a block map).
3620          */
3621         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3622                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3623
3624         old_file_type = old.de->file_type;
3625         if (whiteout) {
3626                 /*
3627                  * Do this before adding a new entry, so the old entry is sure
3628                  * to be still pointing to the valid old entry.
3629                  */
3630                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3631                                      EXT4_FT_CHRDEV);
3632                 if (retval)
3633                         goto end_rename;
3634                 ext4_mark_inode_dirty(handle, whiteout);
3635         }
3636         if (!new.bh) {
3637                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3638                 if (retval)
3639                         goto end_rename;
3640         } else {
3641                 retval = ext4_setent(handle, &new,
3642                                      old.inode->i_ino, old_file_type);
3643                 if (retval)
3644                         goto end_rename;
3645         }
3646         if (force_reread)
3647                 force_reread = !ext4_test_inode_flag(new.dir,
3648                                                      EXT4_INODE_INLINE_DATA);
3649
3650         /*
3651          * Like most other Unix systems, set the ctime for inodes on a
3652          * rename.
3653          */
3654         old.inode->i_ctime = ext4_current_time(old.inode);
3655         ext4_mark_inode_dirty(handle, old.inode);
3656
3657         if (!whiteout) {
3658                 /*
3659                  * ok, that's it
3660                  */
3661                 ext4_rename_delete(handle, &old, force_reread);
3662         }
3663
3664         if (new.inode) {
3665                 ext4_dec_count(handle, new.inode);
3666                 new.inode->i_ctime = ext4_current_time(new.inode);
3667         }
3668         old.dir->i_ctime = old.dir->i_mtime = ext4_current_time(old.dir);
3669         ext4_update_dx_flag(old.dir);
3670         if (old.dir_bh) {
3671                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3672                 if (retval)
3673                         goto end_rename;
3674
3675                 ext4_dec_count(handle, old.dir);
3676                 if (new.inode) {
3677                         /* checked ext4_empty_dir above, can't have another
3678                          * parent, ext4_dec_count() won't work for many-linked
3679                          * dirs */
3680                         clear_nlink(new.inode);
3681                 } else {
3682                         ext4_inc_count(handle, new.dir);
3683                         ext4_update_dx_flag(new.dir);
3684                         ext4_mark_inode_dirty(handle, new.dir);
3685                 }
3686         }
3687         ext4_mark_inode_dirty(handle, old.dir);
3688         if (new.inode) {
3689                 ext4_mark_inode_dirty(handle, new.inode);
3690                 if (!new.inode->i_nlink)
3691                         ext4_orphan_add(handle, new.inode);
3692         }
3693         retval = 0;
3694
3695 end_rename:
3696         brelse(old.dir_bh);
3697         brelse(old.bh);
3698         brelse(new.bh);
3699         if (whiteout) {
3700                 if (retval)
3701                         drop_nlink(whiteout);
3702                 unlock_new_inode(whiteout);
3703                 iput(whiteout);
3704         }
3705         if (handle)
3706                 ext4_journal_stop(handle);
3707         return retval;
3708 }
3709
3710 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3711                              struct inode *new_dir, struct dentry *new_dentry)
3712 {
3713         handle_t *handle = NULL;
3714         struct ext4_renament old = {
3715                 .dir = old_dir,
3716                 .dentry = old_dentry,
3717                 .inode = d_inode(old_dentry),
3718         };
3719         struct ext4_renament new = {
3720                 .dir = new_dir,
3721                 .dentry = new_dentry,
3722                 .inode = d_inode(new_dentry),
3723         };
3724         u8 new_file_type;
3725         int retval;
3726
3727         if ((ext4_encrypted_inode(old_dir) ||
3728              ext4_encrypted_inode(new_dir)) &&
3729             (old_dir != new_dir) &&
3730             (!fscrypt_has_permitted_context(new_dir, old.inode) ||
3731              !fscrypt_has_permitted_context(old_dir, new.inode)))
3732                 return -EPERM;
3733
3734         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
3735              !projid_eq(EXT4_I(new_dir)->i_projid,
3736                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
3737             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
3738              !projid_eq(EXT4_I(old_dir)->i_projid,
3739                         EXT4_I(new_dentry->d_inode)->i_projid)))
3740                 return -EXDEV;
3741
3742         retval = dquot_initialize(old.dir);
3743         if (retval)
3744                 return retval;
3745         retval = dquot_initialize(new.dir);
3746         if (retval)
3747                 return retval;
3748
3749         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3750                                  &old.de, &old.inlined);
3751         if (IS_ERR(old.bh))
3752                 return PTR_ERR(old.bh);
3753         /*
3754          *  Check for inode number is _not_ due to possible IO errors.
3755          *  We might rmdir the source, keep it as pwd of some process
3756          *  and merrily kill the link to whatever was created under the
3757          *  same name. Goodbye sticky bit ;-<
3758          */
3759         retval = -ENOENT;
3760         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3761                 goto end_rename;
3762
3763         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3764                                  &new.de, &new.inlined);
3765         if (IS_ERR(new.bh)) {
3766                 retval = PTR_ERR(new.bh);
3767                 new.bh = NULL;
3768                 goto end_rename;
3769         }
3770
3771         /* RENAME_EXCHANGE case: old *and* new must both exist */
3772         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3773                 goto end_rename;
3774
3775         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3776                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3777                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3778         if (IS_ERR(handle)) {
3779                 retval = PTR_ERR(handle);
3780                 handle = NULL;
3781                 goto end_rename;
3782         }
3783
3784         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3785                 ext4_handle_sync(handle);
3786
3787         if (S_ISDIR(old.inode->i_mode)) {
3788                 old.is_dir = true;
3789                 retval = ext4_rename_dir_prepare(handle, &old);
3790                 if (retval)
3791                         goto end_rename;
3792         }
3793         if (S_ISDIR(new.inode->i_mode)) {
3794                 new.is_dir = true;
3795                 retval = ext4_rename_dir_prepare(handle, &new);
3796                 if (retval)
3797                         goto end_rename;
3798         }
3799
3800         /*
3801          * Other than the special case of overwriting a directory, parents'
3802          * nlink only needs to be modified if this is a cross directory rename.
3803          */
3804         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3805                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3806                 new.dir_nlink_delta = -old.dir_nlink_delta;
3807                 retval = -EMLINK;
3808                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3809                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3810                         goto end_rename;
3811         }
3812
3813         new_file_type = new.de->file_type;
3814         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3815         if (retval)
3816                 goto end_rename;
3817
3818         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3819         if (retval)
3820                 goto end_rename;
3821
3822         /*
3823          * Like most other Unix systems, set the ctime for inodes on a
3824          * rename.
3825          */
3826         old.inode->i_ctime = ext4_current_time(old.inode);
3827         new.inode->i_ctime = ext4_current_time(new.inode);
3828         ext4_mark_inode_dirty(handle, old.inode);
3829         ext4_mark_inode_dirty(handle, new.inode);
3830
3831         if (old.dir_bh) {
3832                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3833                 if (retval)
3834                         goto end_rename;
3835         }
3836         if (new.dir_bh) {
3837                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3838                 if (retval)
3839                         goto end_rename;
3840         }
3841         ext4_update_dir_count(handle, &old);
3842         ext4_update_dir_count(handle, &new);
3843         retval = 0;
3844
3845 end_rename:
3846         brelse(old.dir_bh);
3847         brelse(new.dir_bh);
3848         brelse(old.bh);
3849         brelse(new.bh);
3850         if (handle)
3851                 ext4_journal_stop(handle);
3852         return retval;
3853 }
3854
3855 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3856                         struct inode *new_dir, struct dentry *new_dentry,
3857                         unsigned int flags)
3858 {
3859         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3860                 return -EINVAL;
3861
3862         if (flags & RENAME_EXCHANGE) {
3863                 return ext4_cross_rename(old_dir, old_dentry,
3864                                          new_dir, new_dentry);
3865         }
3866
3867         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3868 }
3869
3870 /*
3871  * directories can handle most operations...
3872  */
3873 const struct inode_operations ext4_dir_inode_operations = {
3874         .create         = ext4_create,
3875         .lookup         = ext4_lookup,
3876         .link           = ext4_link,
3877         .unlink         = ext4_unlink,
3878         .symlink        = ext4_symlink,
3879         .mkdir          = ext4_mkdir,
3880         .rmdir          = ext4_rmdir,
3881         .mknod          = ext4_mknod,
3882         .tmpfile        = ext4_tmpfile,
3883         .rename2        = ext4_rename2,
3884         .setattr        = ext4_setattr,
3885         .setxattr       = generic_setxattr,
3886         .getxattr       = generic_getxattr,
3887         .listxattr      = ext4_listxattr,
3888         .removexattr    = generic_removexattr,
3889         .get_acl        = ext4_get_acl,
3890         .set_acl        = ext4_set_acl,
3891         .fiemap         = ext4_fiemap,
3892 };
3893
3894 const struct inode_operations ext4_special_inode_operations = {
3895         .setattr        = ext4_setattr,
3896         .setxattr       = generic_setxattr,
3897         .getxattr       = generic_getxattr,
3898         .listxattr      = ext4_listxattr,
3899         .removexattr    = generic_removexattr,
3900         .get_acl        = ext4_get_acl,
3901         .set_acl        = ext4_set_acl,
3902 };