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(KERN_CONT " %x->%lu",
 583                        i ? dx_get_hash(entries + i) : 0,
 584                        (unsigned long)dx_get_block(entries + i));
 585         }
 586         printk(KERN_CONT "\n");
 587 }
 588
 589 struct stats
 590 {
 591         unsigned names;
 592         unsigned space;
 593         unsigned bcount;
 594 };
 595
 596 static struct stats dx_show_leaf(struct inode *dir,
 597                                 struct dx_hash_info *hinfo,
 598                                 struct ext4_dir_entry_2 *de,
 599                                 int size, int show_names)
 600 {
 601         unsigned names = 0, space = 0;
 602         char *base = (char *) de;
 603         struct dx_hash_info h = *hinfo;
 604
 605         printk("names: ");
 606         while ((char *) de < base + size)
 607         {
 608                 if (de->inode)
 609                 {
 610                         if (show_names)
 611                         {
 612 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 613                                 int len;
 614                                 char *name;
 615                                 struct fscrypt_str fname_crypto_str =
 616                                         FSTR_INIT(NULL, 0);
 617                                 int res = 0;
 618
 619                                 name  = de->name;
 620                                 len = de->name_len;
 621                                 if (ext4_encrypted_inode(dir))
 622                                         res = fscrypt_get_encryption_info(dir);
 623                                 if (res) {
 624                                         printk(KERN_WARNING "Error setting up"
 625                                                " fname crypto: %d\n", res);
 626                                 }
 627                                 if (!fscrypt_has_encryption_key(dir)) {
 628                                         /* Directory is not encrypted */
 629                                         ext4fs_dirhash(de->name,
 630                                                 de->name_len, &h);
 631                                         printk("%*.s:(U)%x.%u ", len,
 632                                                name, h.hash,
 633                                                (unsigned) ((char *) de
 634                                                            - base));
 635                                 } else {
 636                                         struct fscrypt_str de_name =
 637                                                 FSTR_INIT(name, len);
 638
 639                                         /* Directory is encrypted */
 640                                         res = fscrypt_fname_alloc_buffer(
 641                                                 dir, len,
 642                                                 &fname_crypto_str);
 643                                         if (res)
 644                                                 printk(KERN_WARNING "Error "
 645                                                         "allocating crypto "
 646                                                         "buffer--skipping "
 647                                                         "crypto\n");
 648                                         res = fscrypt_fname_disk_to_usr(dir,
 649                                                 0, 0, &de_name,
 650                                                 &fname_crypto_str);
 651                                         if (res) {
 652                                                 printk(KERN_WARNING "Error "
 653                                                         "converting filename "
 654                                                         "from disk to usr"
 655                                                         "\n");
 656                                                 name = "??";
 657                                                 len = 2;
 658                                         } else {
 659                                                 name = fname_crypto_str.name;
 660                                                 len = fname_crypto_str.len;
 661                                         }
 662                                         ext4fs_dirhash(de->name, de->name_len,
 663                                                        &h);
 664                                         printk("%*.s:(E)%x.%u ", len, name,
 665                                                h.hash, (unsigned) ((char *) de
 666                                                                    - base));
 667                                         fscrypt_fname_free_buffer(
 668                                                         &fname_crypto_str);
 669                                 }
 670 #else
 671                                 int len = de->name_len;
 672                                 char *name = de->name;
 673                                 ext4fs_dirhash(de->name, de->name_len, &h);
 674                                 printk("%*.s:%x.%u ", len, name, h.hash,
 675                                        (unsigned) ((char *) de - base));
 676 #endif
 677                         }
 678                         space += EXT4_DIR_REC_LEN(de->name_len);
 679                         names++;
 680                 }
 681                 de = ext4_next_entry(de, size);
 682         }
 683         printk(KERN_CONT "(%i)\n", names);
 684         return (struct stats) { names, space, 1 };
 685 }
 686
 687 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 688                              struct dx_entry *entries, int levels)
 689 {
 690         unsigned blocksize = dir->i_sb->s_blocksize;
 691         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
 692         unsigned bcount = 0;
 693         struct buffer_head *bh;
 694         printk("%i indexed blocks...\n", count);
 695         for (i = 0; i < count; i++, entries++)
 696         {
 697                 ext4_lblk_t block = dx_get_block(entries);
 698                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
 699                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
 700                 struct stats stats;
 701                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
 702                 bh = ext4_bread(NULL,dir, block, 0);
 703                 if (!bh || IS_ERR(bh))
 704                         continue;
 705                 stats = levels?
 706                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
 707                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
 708                         bh->b_data, blocksize, 0);
 709                 names += stats.names;
 710                 space += stats.space;
 711                 bcount += stats.bcount;
 712                 brelse(bh);
 713         }
 714         if (bcount)
 715                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
 716                        levels ? "" : "   ", names, space/bcount,
 717                        (space/bcount)*100/blocksize);
 718         return (struct stats) { names, space, bcount};
 719 }
 720 #endif /* DX_DEBUG */
 721
 722 /*
 723  * Probe for a directory leaf block to search.
 724  *
 725  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
 726  * error in the directory index, and the caller should fall back to
 727  * searching the directory normally.  The callers of dx_probe **MUST**
 728  * check for this error code, and make sure it never gets reflected
 729  * back to userspace.
 730  */
 731 static struct dx_frame *
 732 dx_probe(struct ext4_filename *fname, struct inode *dir,
 733          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
 734 {
 735         unsigned count, indirect;
 736         struct dx_entry *at, *entries, *p, *q, *m;
 737         struct dx_root *root;
 738         struct dx_frame *frame = frame_in;
 739         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
 740         u32 hash;
 741
 742         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
 743         if (IS_ERR(frame->bh))
 744                 return (struct dx_frame *) frame->bh;
 745
 746         root = (struct dx_root *) frame->bh->b_data;
 747         if (root->info.hash_version != DX_HASH_TEA &&
 748             root->info.hash_version != DX_HASH_HALF_MD4 &&
 749             root->info.hash_version != DX_HASH_LEGACY) {
 750                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
 751                                    root->info.hash_version);
 752                 goto fail;
 753         }
 754         if (fname)
 755                 hinfo = &fname->hinfo;
 756         hinfo->hash_version = root->info.hash_version;
 757         if (hinfo->hash_version <= DX_HASH_TEA)
 758                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 759         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 760         if (fname && fname_name(fname))
 761                 ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
 762         hash = hinfo->hash;
 763
 764         if (root->info.unused_flags & 1) {
 765                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
 766                                    root->info.unused_flags);
 767                 goto fail;
 768         }
 769
 770         indirect = root->info.indirect_levels;
 771         if (indirect > 1) {
 772                 ext4_warning_inode(dir, "Unimplemented hash depth: %#06x",
 773                                    root->info.indirect_levels);
 774                 goto fail;
 775         }
 776
 777         entries = (struct dx_entry *)(((char *)&root->info) +
 778                                       root->info.info_length);
 779
 780         if (dx_get_limit(entries) != dx_root_limit(dir,
 781                                                    root->info.info_length)) {
 782                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 783                                    dx_get_limit(entries),
 784                                    dx_root_limit(dir, root->info.info_length));
 785                 goto fail;
 786         }
 787
 788         dxtrace(printk("Look up %x", hash));
 789         while (1) {
 790                 count = dx_get_count(entries);
 791                 if (!count || count > dx_get_limit(entries)) {
 792                         ext4_warning_inode(dir,
 793                                            "dx entry: count %u beyond limit %u",
 794                                            count, dx_get_limit(entries));
 795                         goto fail;
 796                 }
 797
 798                 p = entries + 1;
 799                 q = entries + count - 1;
 800                 while (p <= q) {
 801                         m = p + (q - p) / 2;
 802                         dxtrace(printk(KERN_CONT "."));
 803                         if (dx_get_hash(m) > hash)
 804                                 q = m - 1;
 805                         else
 806                                 p = m + 1;
 807                 }
 808
 809                 if (0) { // linear search cross check
 810                         unsigned n = count - 1;
 811                         at = entries;
 812                         while (n--)
 813                         {
 814                                 dxtrace(printk(KERN_CONT ","));
 815                                 if (dx_get_hash(++at) > hash)
 816                                 {
 817                                         at--;
 818                                         break;
 819                                 }
 820                         }
 821                         assert (at == p - 1);
 822                 }
 823
 824                 at = p - 1;
 825                 dxtrace(printk(KERN_CONT " %x->%u\n",
 826                                at == entries ? 0 : dx_get_hash(at),
 827                                dx_get_block(at)));
 828                 frame->entries = entries;
 829                 frame->at = at;
 830                 if (!indirect--)
 831                         return frame;
 832                 frame++;
 833                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
 834                 if (IS_ERR(frame->bh)) {
 835                         ret_err = (struct dx_frame *) frame->bh;
 836                         frame->bh = NULL;
 837                         goto fail;
 838                 }
 839                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
 840
 841                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
 842                         ext4_warning_inode(dir,
 843                                 "dx entry: limit %u != node limit %u",
 844                                 dx_get_limit(entries), dx_node_limit(dir));
 845                         goto fail;
 846                 }
 847         }
 848 fail:
 849         while (frame >= frame_in) {
 850                 brelse(frame->bh);
 851                 frame--;
 852         }
 853
 854         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
 855                 ext4_warning_inode(dir,
 856                         "Corrupt directory, running e2fsck is recommended");
 857         return ret_err;
 858 }
 859
 860 static void dx_release(struct dx_frame *frames)
 861 {
 862         if (frames[0].bh == NULL)
 863                 return;
 864
 865         if (((struct dx_root *)frames[0].bh->b_data)->info.indirect_levels)
 866                 brelse(frames[1].bh);
 867         brelse(frames[0].bh);
 868 }
 869
 870 /*
 871  * This function increments the frame pointer to search the next leaf
 872  * block, and reads in the necessary intervening nodes if the search
 873  * should be necessary.  Whether or not the search is necessary is
 874  * controlled by the hash parameter.  If the hash value is even, then
 875  * the search is only continued if the next block starts with that
 876  * hash value.  This is used if we are searching for a specific file.
 877  *
 878  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
 879  *
 880  * This function returns 1 if the caller should continue to search,
 881  * or 0 if it should not.  If there is an error reading one of the
 882  * index blocks, it will a negative error code.
 883  *
 884  * If start_hash is non-null, it will be filled in with the starting
 885  * hash of the next page.
 886  */
 887 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 888                                  struct dx_frame *frame,
 889                                  struct dx_frame *frames,
 890                                  __u32 *start_hash)
 891 {
 892         struct dx_frame *p;
 893         struct buffer_head *bh;
 894         int num_frames = 0;
 895         __u32 bhash;
 896
 897         p = frame;
 898         /*
 899          * Find the next leaf page by incrementing the frame pointer.
 900          * If we run out of entries in the interior node, loop around and
 901          * increment pointer in the parent node.  When we break out of
 902          * this loop, num_frames indicates the number of interior
 903          * nodes need to be read.
 904          */
 905         while (1) {
 906                 if (++(p->at) < p->entries + dx_get_count(p->entries))
 907                         break;
 908                 if (p == frames)
 909                         return 0;
 910                 num_frames++;
 911                 p--;
 912         }
 913
 914         /*
 915          * If the hash is 1, then continue only if the next page has a
 916          * continuation hash of any value.  This is used for readdir
 917          * handling.  Otherwise, check to see if the hash matches the
 918          * desired contiuation hash.  If it doesn't, return since
 919          * there's no point to read in the successive index pages.
 920          */
 921         bhash = dx_get_hash(p->at);
 922         if (start_hash)
 923                 *start_hash = bhash;
 924         if ((hash & 1) == 0) {
 925                 if ((bhash & ~1) != hash)
 926                         return 0;
 927         }
 928         /*
 929          * If the hash is HASH_NB_ALWAYS, we always go to the next
 930          * block so no check is necessary
 931          */
 932         while (num_frames--) {
 933                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
 934                 if (IS_ERR(bh))
 935                         return PTR_ERR(bh);
 936                 p++;
 937                 brelse(p->bh);
 938                 p->bh = bh;
 939                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
 940         }
 941         return 1;
 942 }
 943
 944
 945 /*
 946  * This function fills a red-black tree with information from a
 947  * directory block.  It returns the number directory entries loaded
 948  * into the tree.  If there is an error it is returned in err.
 949  */
 950 static int htree_dirblock_to_tree(struct file *dir_file,
 951                                   struct inode *dir, ext4_lblk_t block,
 952                                   struct dx_hash_info *hinfo,
 953                                   __u32 start_hash, __u32 start_minor_hash)
 954 {
 955         struct buffer_head *bh;
 956         struct ext4_dir_entry_2 *de, *top;
 957         int err = 0, count = 0;
 958         struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
 959
 960         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 961                                                         (unsigned long)block));
 962         bh = ext4_read_dirblock(dir, block, DIRENT);
 963         if (IS_ERR(bh))
 964                 return PTR_ERR(bh);
 965
 966         de = (struct ext4_dir_entry_2 *) bh->b_data;
 967         top = (struct ext4_dir_entry_2 *) ((char *) de +
 968                                            dir->i_sb->s_blocksize -
 969                                            EXT4_DIR_REC_LEN(0));
 970 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 971         /* Check if the directory is encrypted */
 972         if (ext4_encrypted_inode(dir)) {
 973                 err = fscrypt_get_encryption_info(dir);
 974                 if (err < 0) {
 975                         brelse(bh);
 976                         return err;
 977                 }
 978                 err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
 979                                                      &fname_crypto_str);
 980                 if (err < 0) {
 981                         brelse(bh);
 982                         return err;
 983                 }
 984         }
 985 #endif
 986         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
 987                 if (ext4_check_dir_entry(dir, NULL, de, bh,
 988                                 bh->b_data, bh->b_size,
 989                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
 990                                          + ((char *)de - bh->b_data))) {
 991                         /* silently ignore the rest of the block */
 992                         break;
 993                 }
 994                 ext4fs_dirhash(de->name, de->name_len, hinfo);
 995                 if ((hinfo->hash < start_hash) ||
 996                     ((hinfo->hash == start_hash) &&
 997                      (hinfo->minor_hash < start_minor_hash)))
 998                         continue;
 999                 if (de->inode == 0)
1000                         continue;
1001                 if (!ext4_encrypted_inode(dir)) {
1002                         tmp_str.name = de->name;
1003                         tmp_str.len = de->name_len;
1004                         err = ext4_htree_store_dirent(dir_file,
1005                                    hinfo->hash, hinfo->minor_hash, de,
1006                                    &tmp_str);
1007                 } else {
1008                         int save_len = fname_crypto_str.len;
1009                         struct fscrypt_str de_name = FSTR_INIT(de->name,
1010                                                                 de->name_len);
1011
1012                         /* Directory is encrypted */
1013                         err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1014                                         hinfo->minor_hash, &de_name,
1015                                         &fname_crypto_str);
1016                         if (err) {
1017                                 count = err;
1018                                 goto errout;
1019                         }
1020                         err = ext4_htree_store_dirent(dir_file,
1021                                    hinfo->hash, hinfo->minor_hash, de,
1022                                         &fname_crypto_str);
1023                         fname_crypto_str.len = save_len;
1024                 }
1025                 if (err != 0) {
1026                         count = err;
1027                         goto errout;
1028                 }
1029                 count++;
1030         }
1031 errout:
1032         brelse(bh);
1033 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1034         fscrypt_fname_free_buffer(&fname_crypto_str);
1035 #endif
1036         return count;
1037 }
1038
1039
1040 /*
1041  * This function fills a red-black tree with information from a
1042  * directory.  We start scanning the directory in hash order, starting
1043  * at start_hash and start_minor_hash.
1044  *
1045  * This function returns the number of entries inserted into the tree,
1046  * or a negative error code.
1047  */
1048 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1049                          __u32 start_minor_hash, __u32 *next_hash)
1050 {
1051         struct dx_hash_info hinfo;
1052         struct ext4_dir_entry_2 *de;
1053         struct dx_frame frames[2], *frame;
1054         struct inode *dir;
1055         ext4_lblk_t block;
1056         int count = 0;
1057         int ret, err;
1058         __u32 hashval;
1059         struct fscrypt_str tmp_str;
1060
1061         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1062                        start_hash, start_minor_hash));
1063         dir = file_inode(dir_file);
1064         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1065                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1066                 if (hinfo.hash_version <= DX_HASH_TEA)
1067                         hinfo.hash_version +=
1068                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1069                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1070                 if (ext4_has_inline_data(dir)) {
1071                         int has_inline_data = 1;
1072                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
1073                                                         &hinfo, start_hash,
1074                                                         start_minor_hash,
1075                                                         &has_inline_data);
1076                         if (has_inline_data) {
1077                                 *next_hash = ~0;
1078                                 return count;
1079                         }
1080                 }
1081                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1082                                                start_hash, start_minor_hash);
1083                 *next_hash = ~0;
1084                 return count;
1085         }
1086         hinfo.hash = start_hash;
1087         hinfo.minor_hash = 0;
1088         frame = dx_probe(NULL, dir, &hinfo, frames);
1089         if (IS_ERR(frame))
1090                 return PTR_ERR(frame);
1091
1092         /* Add '.' and '..' from the htree header */
1093         if (!start_hash && !start_minor_hash) {
1094                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1095                 tmp_str.name = de->name;
1096                 tmp_str.len = de->name_len;
1097                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1098                                               de, &tmp_str);
1099                 if (err != 0)
1100                         goto errout;
1101                 count++;
1102         }
1103         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1104                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1105                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1106                 tmp_str.name = de->name;
1107                 tmp_str.len = de->name_len;
1108                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1109                                               de, &tmp_str);
1110                 if (err != 0)
1111                         goto errout;
1112                 count++;
1113         }
1114
1115         while (1) {
1116                 if (fatal_signal_pending(current)) {
1117                         err = -ERESTARTSYS;
1118                         goto errout;
1119                 }
1120                 cond_resched();
1121                 block = dx_get_block(frame->at);
1122                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1123                                              start_hash, start_minor_hash);
1124                 if (ret < 0) {
1125                         err = ret;
1126                         goto errout;
1127                 }
1128                 count += ret;
1129                 hashval = ~0;
1130                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1131                                             frame, frames, &hashval);
1132                 *next_hash = hashval;
1133                 if (ret < 0) {
1134                         err = ret;
1135                         goto errout;
1136                 }
1137                 /*
1138                  * Stop if:  (a) there are no more entries, or
1139                  * (b) we have inserted at least one entry and the
1140                  * next hash value is not a continuation
1141                  */
1142                 if ((ret == 0) ||
1143                     (count && ((hashval & 1) == 0)))
1144                         break;
1145         }
1146         dx_release(frames);
1147         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1148                        "next hash: %x\n", count, *next_hash));
1149         return count;
1150 errout:
1151         dx_release(frames);
1152         return (err);
1153 }
1154
1155 static inline int search_dirblock(struct buffer_head *bh,
1156                                   struct inode *dir,
1157                                   struct ext4_filename *fname,
1158                                   unsigned int offset,
1159                                   struct ext4_dir_entry_2 **res_dir)
1160 {
1161         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1162                                fname, offset, res_dir);
1163 }
1164
1165 /*
1166  * Directory block splitting, compacting
1167  */
1168
1169 /*
1170  * Create map of hash values, offsets, and sizes, stored at end of block.
1171  * Returns number of entries mapped.
1172  */
1173 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
1174                        unsigned blocksize, struct dx_hash_info *hinfo,
1175                        struct dx_map_entry *map_tail)
1176 {
1177         int count = 0;
1178         char *base = (char *) de;
1179         struct dx_hash_info h = *hinfo;
1180
1181         while ((char *) de < base + blocksize) {
1182                 if (de->name_len && de->inode) {
1183                         ext4fs_dirhash(de->name, de->name_len, &h);
1184                         map_tail--;
1185                         map_tail->hash = h.hash;
1186                         map_tail->offs = ((char *) de - base)>>2;
1187                         map_tail->size = le16_to_cpu(de->rec_len);
1188                         count++;
1189                         cond_resched();
1190                 }
1191                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1192                 de = ext4_next_entry(de, blocksize);
1193         }
1194         return count;
1195 }
1196
1197 /* Sort map by hash value */
1198 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1199 {
1200         struct dx_map_entry *p, *q, *top = map + count - 1;
1201         int more;
1202         /* Combsort until bubble sort doesn't suck */
1203         while (count > 2) {
1204                 count = count*10/13;
1205                 if (count - 9 < 2) /* 9, 10 -> 11 */
1206                         count = 11;
1207                 for (p = top, q = p - count; q >= map; p--, q--)
1208                         if (p->hash < q->hash)
1209                                 swap(*p, *q);
1210         }
1211         /* Garden variety bubble sort */
1212         do {
1213                 more = 0;
1214                 q = top;
1215                 while (q-- > map) {
1216                         if (q[1].hash >= q[0].hash)
1217                                 continue;
1218                         swap(*(q+1), *q);
1219                         more = 1;
1220                 }
1221         } while(more);
1222 }
1223
1224 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1225 {
1226         struct dx_entry *entries = frame->entries;
1227         struct dx_entry *old = frame->at, *new = old + 1;
1228         int count = dx_get_count(entries);
1229
1230         assert(count < dx_get_limit(entries));
1231         assert(old < entries + count);
1232         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1233         dx_set_hash(new, hash);
1234         dx_set_block(new, block);
1235         dx_set_count(entries, count + 1);
1236 }
1237
1238 /*
1239  * Test whether a directory entry matches the filename being searched for.
1240  *
1241  * Return: %true if the directory entry matches, otherwise %false.
1242  */
1243 static inline bool ext4_match(const struct ext4_filename *fname,
1244                               const struct ext4_dir_entry_2 *de)
1245 {
1246         struct fscrypt_name f;
1247
1248         if (!de->inode)
1249                 return false;
1250
1251         f.usr_fname = fname->usr_fname;
1252         f.disk_name = fname->disk_name;
1253 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1254         f.crypto_buf = fname->crypto_buf;
1255 #endif
1256         return fscrypt_match_name(&f, de->name, de->name_len);
1257 }
1258
1259 /*
1260  * Returns 0 if not found, -1 on failure, and 1 on success
1261  */
1262 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1263                     struct inode *dir, struct ext4_filename *fname,
1264                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1265 {
1266         struct ext4_dir_entry_2 * de;
1267         char * dlimit;
1268         int de_len;
1269
1270         de = (struct ext4_dir_entry_2 *)search_buf;
1271         dlimit = search_buf + buf_size;
1272         while ((char *) de < dlimit) {
1273                 /* this code is executed quadratically often */
1274                 /* do minimal checking `by hand' */
1275                 if ((char *) de + de->name_len <= dlimit &&
1276                     ext4_match(fname, de)) {
1277                         /* found a match - just to be sure, do
1278                          * a full check */
1279                         if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
1280                                                  bh->b_size, offset))
1281                                 return -1;
1282                         *res_dir = de;
1283                         return 1;
1284                 }
1285                 /* prevent looping on a bad block */
1286                 de_len = ext4_rec_len_from_disk(de->rec_len,
1287                                                 dir->i_sb->s_blocksize);
1288                 if (de_len <= 0)
1289                         return -1;
1290                 offset += de_len;
1291                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1292         }
1293         return 0;
1294 }
1295
1296 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1297                                struct ext4_dir_entry *de)
1298 {
1299         struct super_block *sb = dir->i_sb;
1300
1301         if (!is_dx(dir))
1302                 return 0;
1303         if (block == 0)
1304                 return 1;
1305         if (de->inode == 0 &&
1306             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1307                         sb->s_blocksize)
1308                 return 1;
1309         return 0;
1310 }
1311
1312 /*
1313  *      ext4_find_entry()
1314  *
1315  * finds an entry in the specified directory with the wanted name. It
1316  * returns the cache buffer in which the entry was found, and the entry
1317  * itself (as a parameter - res_dir). It does NOT read the inode of the
1318  * entry - you'll have to do that yourself if you want to.
1319  *
1320  * The returned buffer_head has ->b_count elevated.  The caller is expected
1321  * to brelse() it when appropriate.
1322  */
1323 static struct buffer_head * ext4_find_entry (struct inode *dir,
1324                                         const struct qstr *d_name,
1325                                         struct ext4_dir_entry_2 **res_dir,
1326                                         int *inlined)
1327 {
1328         struct super_block *sb;
1329         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1330         struct buffer_head *bh, *ret = NULL;
1331         ext4_lblk_t start, block, b;
1332         const u8 *name = d_name->name;
1333         int ra_max = 0;         /* Number of bh's in the readahead
1334                                    buffer, bh_use[] */
1335         int ra_ptr = 0;         /* Current index into readahead
1336                                    buffer */
1337         int num = 0;
1338         ext4_lblk_t  nblocks;
1339         int i, namelen, retval;
1340         struct ext4_filename fname;
1341
1342         *res_dir = NULL;
1343         sb = dir->i_sb;
1344         namelen = d_name->len;
1345         if (namelen > EXT4_NAME_LEN)
1346                 return NULL;
1347
1348         retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1349         if (retval == -ENOENT)
1350                 return NULL;
1351         if (retval)
1352                 return ERR_PTR(retval);
1353
1354         if (ext4_has_inline_data(dir)) {
1355                 int has_inline_data = 1;
1356                 ret = ext4_find_inline_entry(dir, &fname, res_dir,
1357                                              &has_inline_data);
1358                 if (has_inline_data) {
1359                         if (inlined)
1360                                 *inlined = 1;
1361                         goto cleanup_and_exit;
1362                 }
1363         }
1364
1365         if ((namelen <= 2) && (name[0] == '.') &&
1366             (name[1] == '.' || name[1] == '\0')) {
1367                 /*
1368                  * "." or ".." will only be in the first block
1369                  * NFS may look up ".."; "." should be handled by the VFS
1370                  */
1371                 block = start = 0;
1372                 nblocks = 1;
1373                 goto restart;
1374         }
1375         if (is_dx(dir)) {
1376                 ret = ext4_dx_find_entry(dir, &fname, res_dir);
1377                 /*
1378                  * On success, or if the error was file not found,
1379                  * return.  Otherwise, fall back to doing a search the
1380                  * old fashioned way.
1381                  */
1382                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1383                         goto cleanup_and_exit;
1384                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1385                                "falling back\n"));
1386         }
1387         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1388         start = EXT4_I(dir)->i_dir_start_lookup;
1389         if (start >= nblocks)
1390                 start = 0;
1391         block = start;
1392 restart:
1393         do {
1394                 /*
1395                  * We deal with the read-ahead logic here.
1396                  */
1397                 if (ra_ptr >= ra_max) {
1398                         /* Refill the readahead buffer */
1399                         ra_ptr = 0;
1400                         b = block;
1401                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
1402                                 /*
1403                                  * Terminate if we reach the end of the
1404                                  * directory and must wrap, or if our
1405                                  * search has finished at this block.
1406                                  */
1407                                 if (b >= nblocks || (num && block == start)) {
1408                                         bh_use[ra_max] = NULL;
1409                                         break;
1410                                 }
1411                                 num++;
1412                                 bh = ext4_getblk(NULL, dir, b++, 0);
1413                                 if (IS_ERR(bh)) {
1414                                         if (ra_max == 0) {
1415                                                 ret = bh;
1416                                                 goto cleanup_and_exit;
1417                                         }
1418                                         break;
1419                                 }
1420                                 bh_use[ra_max] = bh;
1421                                 if (bh)
1422                                         ll_rw_block(REQ_OP_READ,
1423                                                     REQ_META | REQ_PRIO,
1424                                                     1, &bh);
1425                         }
1426                 }
1427                 if ((bh = bh_use[ra_ptr++]) == NULL)
1428                         goto next;
1429                 wait_on_buffer(bh);
1430                 if (!buffer_uptodate(bh)) {
1431                         /* read error, skip block & hope for the best */
1432                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1433                                          (unsigned long) block);
1434                         brelse(bh);
1435                         goto next;
1436                 }
1437                 if (!buffer_verified(bh) &&
1438                     !is_dx_internal_node(dir, block,
1439                                          (struct ext4_dir_entry *)bh->b_data) &&
1440                     !ext4_dirent_csum_verify(dir,
1441                                 (struct ext4_dir_entry *)bh->b_data)) {
1442                         EXT4_ERROR_INODE(dir, "checksumming directory "
1443                                          "block %lu", (unsigned long)block);
1444                         brelse(bh);
1445                         goto next;
1446                 }
1447                 set_buffer_verified(bh);
1448                 i = search_dirblock(bh, dir, &fname,
1449                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1450                 if (i == 1) {
1451                         EXT4_I(dir)->i_dir_start_lookup = block;
1452                         ret = bh;
1453                         goto cleanup_and_exit;
1454                 } else {
1455                         brelse(bh);
1456                         if (i < 0)
1457                                 goto cleanup_and_exit;
1458                 }
1459         next:
1460                 if (++block >= nblocks)
1461                         block = 0;
1462         } while (block != start);
1463
1464         /*
1465          * If the directory has grown while we were searching, then
1466          * search the last part of the directory before giving up.
1467          */
1468         block = nblocks;
1469         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1470         if (block < nblocks) {
1471                 start = 0;
1472                 goto restart;
1473         }
1474
1475 cleanup_and_exit:
1476         /* Clean up the read-ahead blocks */
1477         for (; ra_ptr < ra_max; ra_ptr++)
1478                 brelse(bh_use[ra_ptr]);
1479         ext4_fname_free_filename(&fname);
1480         return ret;
1481 }
1482
1483 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1484                         struct ext4_filename *fname,
1485                         struct ext4_dir_entry_2 **res_dir)
1486 {
1487         struct super_block * sb = dir->i_sb;
1488         struct dx_frame frames[2], *frame;
1489         struct buffer_head *bh;
1490         ext4_lblk_t block;
1491         int retval;
1492
1493 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1494         *res_dir = NULL;
1495 #endif
1496         frame = dx_probe(fname, dir, NULL, frames);
1497         if (IS_ERR(frame))
1498                 return (struct buffer_head *) frame;
1499         do {
1500                 block = dx_get_block(frame->at);
1501                 bh = ext4_read_dirblock(dir, block, DIRENT);
1502                 if (IS_ERR(bh))
1503                         goto errout;
1504
1505                 retval = search_dirblock(bh, dir, fname,
1506                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1507                                          res_dir);
1508                 if (retval == 1)
1509                         goto success;
1510                 brelse(bh);
1511                 if (retval == -1) {
1512                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1513                         goto errout;
1514                 }
1515
1516                 /* Check to see if we should continue to search */
1517                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1518                                                frames, NULL);
1519                 if (retval < 0) {
1520                         ext4_warning_inode(dir,
1521                                 "error %d reading directory index block",
1522                                 retval);
1523                         bh = ERR_PTR(retval);
1524                         goto errout;
1525                 }
1526         } while (retval == 1);
1527
1528         bh = NULL;
1529 errout:
1530         dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1531 success:
1532         dx_release(frames);
1533         return bh;
1534 }
1535
1536 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1537 {
1538         struct inode *inode;
1539         struct ext4_dir_entry_2 *de;
1540         struct buffer_head *bh;
1541
1542         if (ext4_encrypted_inode(dir)) {
1543                 int res = fscrypt_get_encryption_info(dir);
1544
1545                 /*
1546                  * DCACHE_ENCRYPTED_WITH_KEY is set if the dentry is
1547                  * created while the directory was encrypted and we
1548                  * have access to the key.
1549                  */
1550                 if (fscrypt_has_encryption_key(dir))
1551                         fscrypt_set_encrypted_dentry(dentry);
1552                 fscrypt_set_d_op(dentry);
1553                 if (res && res != -ENOKEY)
1554                         return ERR_PTR(res);
1555         }
1556
1557        if (dentry->d_name.len > EXT4_NAME_LEN)
1558                return ERR_PTR(-ENAMETOOLONG);
1559
1560         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1561         if (IS_ERR(bh))
1562                 return (struct dentry *) bh;
1563         inode = NULL;
1564         if (bh) {
1565                 __u32 ino = le32_to_cpu(de->inode);
1566                 brelse(bh);
1567                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1568                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1569                         return ERR_PTR(-EFSCORRUPTED);
1570                 }
1571                 if (unlikely(ino == dir->i_ino)) {
1572                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1573                                          dentry);
1574                         return ERR_PTR(-EFSCORRUPTED);
1575                 }
1576                 inode = ext4_iget_normal(dir->i_sb, ino);
1577                 if (inode == ERR_PTR(-ESTALE)) {
1578                         EXT4_ERROR_INODE(dir,
1579                                          "deleted inode referenced: %u",
1580                                          ino);
1581                         return ERR_PTR(-EFSCORRUPTED);
1582                 }
1583                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1584                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1585                     !fscrypt_has_permitted_context(dir, inode)) {
1586                         ext4_warning(inode->i_sb,
1587                                      "Inconsistent encryption contexts: %lu/%lu",
1588                                      dir->i_ino, inode->i_ino);
1589                         iput(inode);
1590                         return ERR_PTR(-EPERM);
1591                 }
1592         }
1593         return d_splice_alias(inode, dentry);
1594 }
1595
1596
1597 struct dentry *ext4_get_parent(struct dentry *child)
1598 {
1599         __u32 ino;
1600         static const struct qstr dotdot = QSTR_INIT("..", 2);
1601         struct ext4_dir_entry_2 * de;
1602         struct buffer_head *bh;
1603
1604         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1605         if (IS_ERR(bh))
1606                 return (struct dentry *) bh;
1607         if (!bh)
1608                 return ERR_PTR(-ENOENT);
1609         ino = le32_to_cpu(de->inode);
1610         brelse(bh);
1611
1612         if (!ext4_valid_inum(child->d_sb, ino)) {
1613                 EXT4_ERROR_INODE(d_inode(child),
1614                                  "bad parent inode number: %u", ino);
1615                 return ERR_PTR(-EFSCORRUPTED);
1616         }
1617
1618         return d_obtain_alias(ext4_iget_normal(child->d_sb, ino));
1619 }
1620
1621 /*
1622  * Move count entries from end of map between two memory locations.
1623  * Returns pointer to last entry moved.
1624  */
1625 static struct ext4_dir_entry_2 *
1626 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1627                 unsigned blocksize)
1628 {
1629         unsigned rec_len = 0;
1630
1631         while (count--) {
1632                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1633                                                 (from + (map->offs<<2));
1634                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1635                 memcpy (to, de, rec_len);
1636                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1637                                 ext4_rec_len_to_disk(rec_len, blocksize);
1638                 de->inode = 0;
1639                 map++;
1640                 to += rec_len;
1641         }
1642         return (struct ext4_dir_entry_2 *) (to - rec_len);
1643 }
1644
1645 /*
1646  * Compact each dir entry in the range to the minimal rec_len.
1647  * Returns pointer to last entry in range.
1648  */
1649 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1650 {
1651         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1652         unsigned rec_len = 0;
1653
1654         prev = to = de;
1655         while ((char*)de < base + blocksize) {
1656                 next = ext4_next_entry(de, blocksize);
1657                 if (de->inode && de->name_len) {
1658                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1659                         if (de > to)
1660                                 memmove(to, de, rec_len);
1661                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1662                         prev = to;
1663                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1664                 }
1665                 de = next;
1666         }
1667         return prev;
1668 }
1669
1670 /*
1671  * Split a full leaf block to make room for a new dir entry.
1672  * Allocate a new block, and move entries so that they are approx. equally full.
1673  * Returns pointer to de in block into which the new entry will be inserted.
1674  */
1675 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1676                         struct buffer_head **bh,struct dx_frame *frame,
1677                         struct dx_hash_info *hinfo)
1678 {
1679         unsigned blocksize = dir->i_sb->s_blocksize;
1680         unsigned count, continued;
1681         struct buffer_head *bh2;
1682         ext4_lblk_t newblock;
1683         u32 hash2;
1684         struct dx_map_entry *map;
1685         char *data1 = (*bh)->b_data, *data2;
1686         unsigned split, move, size;
1687         struct ext4_dir_entry_2 *de = NULL, *de2;
1688         struct ext4_dir_entry_tail *t;
1689         int     csum_size = 0;
1690         int     err = 0, i;
1691
1692         if (ext4_has_metadata_csum(dir->i_sb))
1693                 csum_size = sizeof(struct ext4_dir_entry_tail);
1694
1695         bh2 = ext4_append(handle, dir, &newblock);
1696         if (IS_ERR(bh2)) {
1697                 brelse(*bh);
1698                 *bh = NULL;
1699                 return (struct ext4_dir_entry_2 *) bh2;
1700         }
1701
1702         BUFFER_TRACE(*bh, "get_write_access");
1703         err = ext4_journal_get_write_access(handle, *bh);
1704         if (err)
1705                 goto journal_error;
1706
1707         BUFFER_TRACE(frame->bh, "get_write_access");
1708         err = ext4_journal_get_write_access(handle, frame->bh);
1709         if (err)
1710                 goto journal_error;
1711
1712         data2 = bh2->b_data;
1713
1714         /* create map in the end of data2 block */
1715         map = (struct dx_map_entry *) (data2 + blocksize);
1716         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1717                              blocksize, hinfo, map);
1718         map -= count;
1719         dx_sort_map(map, count);
1720         /* Split the existing block in the middle, size-wise */
1721         size = 0;
1722         move = 0;
1723         for (i = count-1; i >= 0; i--) {
1724                 /* is more than half of this entry in 2nd half of the block? */
1725                 if (size + map[i].size/2 > blocksize/2)
1726                         break;
1727                 size += map[i].size;
1728                 move++;
1729         }
1730         /* map index at which we will split */
1731         split = count - move;
1732         hash2 = map[split].hash;
1733         continued = hash2 == map[split - 1].hash;
1734         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1735                         (unsigned long)dx_get_block(frame->at),
1736                                         hash2, split, count-split));
1737
1738         /* Fancy dance to stay within two buffers */
1739         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1740                               blocksize);
1741         de = dx_pack_dirents(data1, blocksize);
1742         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1743                                            (char *) de,
1744                                            blocksize);
1745         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1746                                             (char *) de2,
1747                                             blocksize);
1748         if (csum_size) {
1749                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1750                 initialize_dirent_tail(t, blocksize);
1751
1752                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1753                 initialize_dirent_tail(t, blocksize);
1754         }
1755
1756         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1757                         blocksize, 1));
1758         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1759                         blocksize, 1));
1760
1761         /* Which block gets the new entry? */
1762         if (hinfo->hash >= hash2) {
1763                 swap(*bh, bh2);
1764                 de = de2;
1765         }
1766         dx_insert_block(frame, hash2 + continued, newblock);
1767         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1768         if (err)
1769                 goto journal_error;
1770         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1771         if (err)
1772                 goto journal_error;
1773         brelse(bh2);
1774         dxtrace(dx_show_index("frame", frame->entries));
1775         return de;
1776
1777 journal_error:
1778         brelse(*bh);
1779         brelse(bh2);
1780         *bh = NULL;
1781         ext4_std_error(dir->i_sb, err);
1782         return ERR_PTR(err);
1783 }
1784
1785 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1786                       struct buffer_head *bh,
1787                       void *buf, int buf_size,
1788                       struct ext4_filename *fname,
1789                       struct ext4_dir_entry_2 **dest_de)
1790 {
1791         struct ext4_dir_entry_2 *de;
1792         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1793         int nlen, rlen;
1794         unsigned int offset = 0;
1795         char *top;
1796
1797         de = (struct ext4_dir_entry_2 *)buf;
1798         top = buf + buf_size - reclen;
1799         while ((char *) de <= top) {
1800                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1801                                          buf, buf_size, offset))
1802                         return -EFSCORRUPTED;
1803                 if (ext4_match(fname, de))
1804                         return -EEXIST;
1805                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1806                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1807                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1808                         break;
1809                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1810                 offset += rlen;
1811         }
1812         if ((char *) de > top)
1813                 return -ENOSPC;
1814
1815         *dest_de = de;
1816         return 0;
1817 }
1818
1819 void ext4_insert_dentry(struct inode *inode,
1820                         struct ext4_dir_entry_2 *de,
1821                         int buf_size,
1822                         struct ext4_filename *fname)
1823 {
1824
1825         int nlen, rlen;
1826
1827         nlen = EXT4_DIR_REC_LEN(de->name_len);
1828         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1829         if (de->inode) {
1830                 struct ext4_dir_entry_2 *de1 =
1831                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1832                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1833                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1834                 de = de1;
1835         }
1836         de->file_type = EXT4_FT_UNKNOWN;
1837         de->inode = cpu_to_le32(inode->i_ino);
1838         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1839         de->name_len = fname_len(fname);
1840         memcpy(de->name, fname_name(fname), fname_len(fname));
1841 }
1842
1843 /*
1844  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1845  * it points to a directory entry which is guaranteed to be large
1846  * enough for new directory entry.  If de is NULL, then
1847  * add_dirent_to_buf will attempt search the directory block for
1848  * space.  It will return -ENOSPC if no space is available, and -EIO
1849  * and -EEXIST if directory entry already exists.
1850  */
1851 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1852                              struct inode *dir,
1853                              struct inode *inode, struct ext4_dir_entry_2 *de,
1854                              struct buffer_head *bh)
1855 {
1856         unsigned int    blocksize = dir->i_sb->s_blocksize;
1857         int             csum_size = 0;
1858         int             err;
1859
1860         if (ext4_has_metadata_csum(inode->i_sb))
1861                 csum_size = sizeof(struct ext4_dir_entry_tail);
1862
1863         if (!de) {
1864                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1865                                         blocksize - csum_size, fname, &de);
1866                 if (err)
1867                         return err;
1868         }
1869         BUFFER_TRACE(bh, "get_write_access");
1870         err = ext4_journal_get_write_access(handle, bh);
1871         if (err) {
1872                 ext4_std_error(dir->i_sb, err);
1873                 return err;
1874         }
1875
1876         /* By now the buffer is marked for journaling */
1877         ext4_insert_dentry(inode, de, blocksize, fname);
1878
1879         /*
1880          * XXX shouldn't update any times until successful
1881          * completion of syscall, but too many callers depend
1882          * on this.
1883          *
1884          * XXX similarly, too many callers depend on
1885          * ext4_new_inode() setting the times, but error
1886          * recovery deletes the inode, so the worst that can
1887          * happen is that the times are slightly out of date
1888          * and/or different from the directory change time.
1889          */
1890         dir->i_mtime = dir->i_ctime = current_time(dir);
1891         ext4_update_dx_flag(dir);
1892         dir->i_version++;
1893         ext4_mark_inode_dirty(handle, dir);
1894         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1895         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1896         if (err)
1897                 ext4_std_error(dir->i_sb, err);
1898         return 0;
1899 }
1900
1901 /*
1902  * This converts a one block unindexed directory to a 3 block indexed
1903  * directory, and adds the dentry to the indexed directory.
1904  */
1905 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1906                             struct inode *dir,
1907                             struct inode *inode, struct buffer_head *bh)
1908 {
1909         struct buffer_head *bh2;
1910         struct dx_root  *root;
1911         struct dx_frame frames[2], *frame;
1912         struct dx_entry *entries;
1913         struct ext4_dir_entry_2 *de, *de2;
1914         struct ext4_dir_entry_tail *t;
1915         char            *data1, *top;
1916         unsigned        len;
1917         int             retval;
1918         unsigned        blocksize;
1919         ext4_lblk_t  block;
1920         struct fake_dirent *fde;
1921         int csum_size = 0;
1922
1923         if (ext4_has_metadata_csum(inode->i_sb))
1924                 csum_size = sizeof(struct ext4_dir_entry_tail);
1925
1926         blocksize =  dir->i_sb->s_blocksize;
1927         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1928         BUFFER_TRACE(bh, "get_write_access");
1929         retval = ext4_journal_get_write_access(handle, bh);
1930         if (retval) {
1931                 ext4_std_error(dir->i_sb, retval);
1932                 brelse(bh);
1933                 return retval;
1934         }
1935         root = (struct dx_root *) bh->b_data;
1936
1937         /* The 0th block becomes the root, move the dirents out */
1938         fde = &root->dotdot;
1939         de = (struct ext4_dir_entry_2 *)((char *)fde +
1940                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1941         if ((char *) de >= (((char *) root) + blocksize)) {
1942                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1943                 brelse(bh);
1944                 return -EFSCORRUPTED;
1945         }
1946         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1947
1948         /* Allocate new block for the 0th block's dirents */
1949         bh2 = ext4_append(handle, dir, &block);
1950         if (IS_ERR(bh2)) {
1951                 brelse(bh);
1952                 return PTR_ERR(bh2);
1953         }
1954         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1955         data1 = bh2->b_data;
1956
1957         memcpy (data1, de, len);
1958         de = (struct ext4_dir_entry_2 *) data1;
1959         top = data1 + len;
1960         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1961                 de = de2;
1962         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1963                                            (char *) de,
1964                                            blocksize);
1965
1966         if (csum_size) {
1967                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1968                 initialize_dirent_tail(t, blocksize);
1969         }
1970
1971         /* Initialize the root; the dot dirents already exist */
1972         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1973         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
1974                                            blocksize);
1975         memset (&root->info, 0, sizeof(root->info));
1976         root->info.info_length = sizeof(root->info);
1977         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1978         entries = root->entries;
1979         dx_set_block(entries, 1);
1980         dx_set_count(entries, 1);
1981         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
1982
1983         /* Initialize as for dx_probe */
1984         fname->hinfo.hash_version = root->info.hash_version;
1985         if (fname->hinfo.hash_version <= DX_HASH_TEA)
1986                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
1987         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1988         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
1989
1990         memset(frames, 0, sizeof(frames));
1991         frame = frames;
1992         frame->entries = entries;
1993         frame->at = entries;
1994         frame->bh = bh;
1995
1996         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1997         if (retval)
1998                 goto out_frames;
1999         retval = ext4_handle_dirty_dirent_node(handle, dir, bh2);
2000         if (retval)
2001                 goto out_frames;
2002
2003         de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
2004         if (IS_ERR(de)) {
2005                 retval = PTR_ERR(de);
2006                 goto out_frames;
2007         }
2008
2009         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2010 out_frames:
2011         /*
2012          * Even if the block split failed, we have to properly write
2013          * out all the changes we did so far. Otherwise we can end up
2014          * with corrupted filesystem.
2015          */
2016         if (retval)
2017                 ext4_mark_inode_dirty(handle, dir);
2018         dx_release(frames);
2019         brelse(bh2);
2020         return retval;
2021 }
2022
2023 /*
2024  *      ext4_add_entry()
2025  *
2026  * adds a file entry to the specified directory, using the same
2027  * semantics as ext4_find_entry(). It returns NULL if it failed.
2028  *
2029  * NOTE!! The inode part of 'de' is left at 0 - which means you
2030  * may not sleep between calling this and putting something into
2031  * the entry, as someone else might have used it while you slept.
2032  */
2033 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2034                           struct inode *inode)
2035 {
2036         struct inode *dir = d_inode(dentry->d_parent);
2037         struct buffer_head *bh = NULL;
2038         struct ext4_dir_entry_2 *de;
2039         struct ext4_dir_entry_tail *t;
2040         struct super_block *sb;
2041         struct ext4_filename fname;
2042         int     retval;
2043         int     dx_fallback=0;
2044         unsigned blocksize;
2045         ext4_lblk_t block, blocks;
2046         int     csum_size = 0;
2047
2048         if (ext4_has_metadata_csum(inode->i_sb))
2049                 csum_size = sizeof(struct ext4_dir_entry_tail);
2050
2051         sb = dir->i_sb;
2052         blocksize = sb->s_blocksize;
2053         if (!dentry->d_name.len)
2054                 return -EINVAL;
2055
2056         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2057         if (retval)
2058                 return retval;
2059
2060         if (ext4_has_inline_data(dir)) {
2061                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2062                 if (retval < 0)
2063                         goto out;
2064                 if (retval == 1) {
2065                         retval = 0;
2066                         goto out;
2067                 }
2068         }
2069
2070         if (is_dx(dir)) {
2071                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2072                 if (!retval || (retval != ERR_BAD_DX_DIR))
2073                         goto out;
2074                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2075                 dx_fallback++;
2076                 ext4_mark_inode_dirty(handle, dir);
2077         }
2078         blocks = dir->i_size >> sb->s_blocksize_bits;
2079         for (block = 0; block < blocks; block++) {
2080                 bh = ext4_read_dirblock(dir, block, DIRENT);
2081                 if (IS_ERR(bh)) {
2082                         retval = PTR_ERR(bh);
2083                         bh = NULL;
2084                         goto out;
2085                 }
2086                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2087                                            NULL, bh);
2088                 if (retval != -ENOSPC)
2089                         goto out;
2090
2091                 if (blocks == 1 && !dx_fallback &&
2092                     ext4_has_feature_dir_index(sb)) {
2093                         retval = make_indexed_dir(handle, &fname, dir,
2094                                                   inode, bh);
2095                         bh = NULL; /* make_indexed_dir releases bh */
2096                         goto out;
2097                 }
2098                 brelse(bh);
2099         }
2100         bh = ext4_append(handle, dir, &block);
2101         if (IS_ERR(bh)) {
2102                 retval = PTR_ERR(bh);
2103                 bh = NULL;
2104                 goto out;
2105         }
2106         de = (struct ext4_dir_entry_2 *) bh->b_data;
2107         de->inode = 0;
2108         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2109
2110         if (csum_size) {
2111                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2112                 initialize_dirent_tail(t, blocksize);
2113         }
2114
2115         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2116 out:
2117         ext4_fname_free_filename(&fname);
2118         brelse(bh);
2119         if (retval == 0)
2120                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2121         return retval;
2122 }
2123
2124 /*
2125  * Returns 0 for success, or a negative error value
2126  */
2127 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2128                              struct inode *dir, struct inode *inode)
2129 {
2130         struct dx_frame frames[2], *frame;
2131         struct dx_entry *entries, *at;
2132         struct buffer_head *bh;
2133         struct super_block *sb = dir->i_sb;
2134         struct ext4_dir_entry_2 *de;
2135         int err;
2136
2137         frame = dx_probe(fname, dir, NULL, frames);
2138         if (IS_ERR(frame))
2139                 return PTR_ERR(frame);
2140         entries = frame->entries;
2141         at = frame->at;
2142         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2143         if (IS_ERR(bh)) {
2144                 err = PTR_ERR(bh);
2145                 bh = NULL;
2146                 goto cleanup;
2147         }
2148
2149         BUFFER_TRACE(bh, "get_write_access");
2150         err = ext4_journal_get_write_access(handle, bh);
2151         if (err)
2152                 goto journal_error;
2153
2154         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2155         if (err != -ENOSPC)
2156                 goto cleanup;
2157
2158         /* Block full, should compress but for now just split */
2159         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2160                        dx_get_count(entries), dx_get_limit(entries)));
2161         /* Need to split index? */
2162         if (dx_get_count(entries) == dx_get_limit(entries)) {
2163                 ext4_lblk_t newblock;
2164                 unsigned icount = dx_get_count(entries);
2165                 int levels = frame - frames;
2166                 struct dx_entry *entries2;
2167                 struct dx_node *node2;
2168                 struct buffer_head *bh2;
2169
2170                 if (levels && (dx_get_count(frames->entries) ==
2171                                dx_get_limit(frames->entries))) {
2172                         ext4_warning_inode(dir, "Directory index full!");
2173                         err = -ENOSPC;
2174                         goto cleanup;
2175                 }
2176                 bh2 = ext4_append(handle, dir, &newblock);
2177                 if (IS_ERR(bh2)) {
2178                         err = PTR_ERR(bh2);
2179                         goto cleanup;
2180                 }
2181                 node2 = (struct dx_node *)(bh2->b_data);
2182                 entries2 = node2->entries;
2183                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2184                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2185                                                            sb->s_blocksize);
2186                 BUFFER_TRACE(frame->bh, "get_write_access");
2187                 err = ext4_journal_get_write_access(handle, frame->bh);
2188                 if (err)
2189                         goto journal_error;
2190                 if (levels) {
2191                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2192                         unsigned hash2 = dx_get_hash(entries + icount1);
2193                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2194                                        icount1, icount2));
2195
2196                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2197                         err = ext4_journal_get_write_access(handle,
2198                                                              frames[0].bh);
2199                         if (err)
2200                                 goto journal_error;
2201
2202                         memcpy((char *) entries2, (char *) (entries + icount1),
2203                                icount2 * sizeof(struct dx_entry));
2204                         dx_set_count(entries, icount1);
2205                         dx_set_count(entries2, icount2);
2206                         dx_set_limit(entries2, dx_node_limit(dir));
2207
2208                         /* Which index block gets the new entry? */
2209                         if (at - entries >= icount1) {
2210                                 frame->at = at = at - entries - icount1 + entries2;
2211                                 frame->entries = entries = entries2;
2212                                 swap(frame->bh, bh2);
2213                         }
2214                         dx_insert_block(frames + 0, hash2, newblock);
2215                         dxtrace(dx_show_index("node", frames[1].entries));
2216                         dxtrace(dx_show_index("node",
2217                                ((struct dx_node *) bh2->b_data)->entries));
2218                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2219                         if (err)
2220                                 goto journal_error;
2221                         brelse (bh2);
2222                 } else {
2223                         dxtrace(printk(KERN_DEBUG
2224                                        "Creating second level index...\n"));
2225                         memcpy((char *) entries2, (char *) entries,
2226                                icount * sizeof(struct dx_entry));
2227                         dx_set_limit(entries2, dx_node_limit(dir));
2228
2229                         /* Set up root */
2230                         dx_set_count(entries, 1);
2231                         dx_set_block(entries + 0, newblock);
2232                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
2233
2234                         /* Add new access path frame */
2235                         frame = frames + 1;
2236                         frame->at = at = at - entries + entries2;
2237                         frame->entries = entries = entries2;
2238                         frame->bh = bh2;
2239                         err = ext4_journal_get_write_access(handle,
2240                                                              frame->bh);
2241                         if (err)
2242                                 goto journal_error;
2243                 }
2244                 err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
2245                 if (err) {
2246                         ext4_std_error(inode->i_sb, err);
2247                         goto cleanup;
2248                 }
2249         }
2250         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2251         if (IS_ERR(de)) {
2252                 err = PTR_ERR(de);
2253                 goto cleanup;
2254         }
2255         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2256         goto cleanup;
2257
2258 journal_error:
2259         ext4_std_error(dir->i_sb, err);
2260 cleanup:
2261         brelse(bh);
2262         dx_release(frames);
2263         return err;
2264 }
2265
2266 /*
2267  * ext4_generic_delete_entry deletes a directory entry by merging it
2268  * with the previous entry
2269  */
2270 int ext4_generic_delete_entry(handle_t *handle,
2271                               struct inode *dir,
2272                               struct ext4_dir_entry_2 *de_del,
2273                               struct buffer_head *bh,
2274                               void *entry_buf,
2275                               int buf_size,
2276                               int csum_size)
2277 {
2278         struct ext4_dir_entry_2 *de, *pde;
2279         unsigned int blocksize = dir->i_sb->s_blocksize;
2280         int i;
2281
2282         i = 0;
2283         pde = NULL;
2284         de = (struct ext4_dir_entry_2 *)entry_buf;
2285         while (i < buf_size - csum_size) {
2286                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2287                                          bh->b_data, bh->b_size, i))
2288                         return -EFSCORRUPTED;
2289                 if (de == de_del)  {
2290                         if (pde)
2291                                 pde->rec_len = ext4_rec_len_to_disk(
2292                                         ext4_rec_len_from_disk(pde->rec_len,
2293                                                                blocksize) +
2294                                         ext4_rec_len_from_disk(de->rec_len,
2295                                                                blocksize),
2296                                         blocksize);
2297                         else
2298                                 de->inode = 0;
2299                         dir->i_version++;
2300                         return 0;
2301                 }
2302                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2303                 pde = de;
2304                 de = ext4_next_entry(de, blocksize);
2305         }
2306         return -ENOENT;
2307 }
2308
2309 static int ext4_delete_entry(handle_t *handle,
2310                              struct inode *dir,
2311                              struct ext4_dir_entry_2 *de_del,
2312                              struct buffer_head *bh)
2313 {
2314         int err, csum_size = 0;
2315
2316         if (ext4_has_inline_data(dir)) {
2317                 int has_inline_data = 1;
2318                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2319                                                &has_inline_data);
2320                 if (has_inline_data)
2321                         return err;
2322         }
2323
2324         if (ext4_has_metadata_csum(dir->i_sb))
2325                 csum_size = sizeof(struct ext4_dir_entry_tail);
2326
2327         BUFFER_TRACE(bh, "get_write_access");
2328         err = ext4_journal_get_write_access(handle, bh);
2329         if (unlikely(err))
2330                 goto out;
2331
2332         err = ext4_generic_delete_entry(handle, dir, de_del,
2333                                         bh, bh->b_data,
2334                                         dir->i_sb->s_blocksize, csum_size);
2335         if (err)
2336                 goto out;
2337
2338         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2339         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2340         if (unlikely(err))
2341                 goto out;
2342
2343         return 0;
2344 out:
2345         if (err != -ENOENT)
2346                 ext4_std_error(dir->i_sb, err);
2347         return err;
2348 }
2349
2350 /*
2351  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
2352  * since this indicates that nlinks count was previously 1.
2353  */
2354 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2355 {
2356         inc_nlink(inode);
2357         if (is_dx(inode) && inode->i_nlink > 1) {
2358                 /* limit is 16-bit i_links_count */
2359                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
2360                         set_nlink(inode, 1);
2361                         ext4_set_feature_dir_nlink(inode->i_sb);
2362                 }
2363         }
2364 }
2365
2366 /*
2367  * If a directory had nlink == 1, then we should let it be 1. This indicates
2368  * directory has >EXT4_LINK_MAX subdirs.
2369  */
2370 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2371 {
2372         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2373                 drop_nlink(inode);
2374 }
2375
2376
2377 static int ext4_add_nondir(handle_t *handle,
2378                 struct dentry *dentry, struct inode *inode)
2379 {
2380         int err = ext4_add_entry(handle, dentry, inode);
2381         if (!err) {
2382                 ext4_mark_inode_dirty(handle, inode);
2383                 unlock_new_inode(inode);
2384                 d_instantiate(dentry, inode);
2385                 return 0;
2386         }
2387         drop_nlink(inode);
2388         unlock_new_inode(inode);
2389         iput(inode);
2390         return err;
2391 }
2392
2393 /*
2394  * By the time this is called, we already have created
2395  * the directory cache entry for the new file, but it
2396  * is so far negative - it has no inode.
2397  *
2398  * If the create succeeds, we fill in the inode information
2399  * with d_instantiate().
2400  */
2401 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2402                        bool excl)
2403 {
2404         handle_t *handle;
2405         struct inode *inode;
2406         int err, credits, retries = 0;
2407
2408         err = dquot_initialize(dir);
2409         if (err)
2410                 return err;
2411
2412         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2413                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2414 retry:
2415         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2416                                             NULL, EXT4_HT_DIR, credits);
2417         handle = ext4_journal_current_handle();
2418         err = PTR_ERR(inode);
2419         if (!IS_ERR(inode)) {
2420                 inode->i_op = &ext4_file_inode_operations;
2421                 inode->i_fop = &ext4_file_operations;
2422                 ext4_set_aops(inode);
2423                 err = ext4_add_nondir(handle, dentry, inode);
2424                 if (!err && IS_DIRSYNC(dir))
2425                         ext4_handle_sync(handle);
2426         }
2427         if (handle)
2428                 ext4_journal_stop(handle);
2429         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2430                 goto retry;
2431         return err;
2432 }
2433
2434 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2435                       umode_t mode, dev_t rdev)
2436 {
2437         handle_t *handle;
2438         struct inode *inode;
2439         int err, credits, retries = 0;
2440
2441         err = dquot_initialize(dir);
2442         if (err)
2443                 return err;
2444
2445         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2446                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2447 retry:
2448         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2449                                             NULL, EXT4_HT_DIR, credits);
2450         handle = ext4_journal_current_handle();
2451         err = PTR_ERR(inode);
2452         if (!IS_ERR(inode)) {
2453                 init_special_inode(inode, inode->i_mode, rdev);
2454                 inode->i_op = &ext4_special_inode_operations;
2455                 err = ext4_add_nondir(handle, dentry, inode);
2456                 if (!err && IS_DIRSYNC(dir))
2457                         ext4_handle_sync(handle);
2458         }
2459         if (handle)
2460                 ext4_journal_stop(handle);
2461         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2462                 goto retry;
2463         return err;
2464 }
2465
2466 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2467 {
2468         handle_t *handle;
2469         struct inode *inode;
2470         int err, retries = 0;
2471
2472         err = dquot_initialize(dir);
2473         if (err)
2474                 return err;
2475
2476 retry:
2477         inode = ext4_new_inode_start_handle(dir, mode,
2478                                             NULL, 0, NULL,
2479                                             EXT4_HT_DIR,
2480                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2481                           4 + EXT4_XATTR_TRANS_BLOCKS);
2482         handle = ext4_journal_current_handle();
2483         err = PTR_ERR(inode);
2484         if (!IS_ERR(inode)) {
2485                 inode->i_op = &ext4_file_inode_operations;
2486                 inode->i_fop = &ext4_file_operations;
2487                 ext4_set_aops(inode);
2488                 d_tmpfile(dentry, inode);
2489                 err = ext4_orphan_add(handle, inode);
2490                 if (err)
2491                         goto err_unlock_inode;
2492                 mark_inode_dirty(inode);
2493                 unlock_new_inode(inode);
2494         }
2495         if (handle)
2496                 ext4_journal_stop(handle);
2497         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2498                 goto retry;
2499         return err;
2500 err_unlock_inode:
2501         ext4_journal_stop(handle);
2502         unlock_new_inode(inode);
2503         return err;
2504 }
2505
2506 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2507                           struct ext4_dir_entry_2 *de,
2508                           int blocksize, int csum_size,
2509                           unsigned int parent_ino, int dotdot_real_len)
2510 {
2511         de->inode = cpu_to_le32(inode->i_ino);
2512         de->name_len = 1;
2513         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2514                                            blocksize);
2515         strcpy(de->name, ".");
2516         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2517
2518         de = ext4_next_entry(de, blocksize);
2519         de->inode = cpu_to_le32(parent_ino);
2520         de->name_len = 2;
2521         if (!dotdot_real_len)
2522                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2523                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2524                                         blocksize);
2525         else
2526                 de->rec_len = ext4_rec_len_to_disk(
2527                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2528         strcpy(de->name, "..");
2529         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2530
2531         return ext4_next_entry(de, blocksize);
2532 }
2533
2534 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2535                              struct inode *inode)
2536 {
2537         struct buffer_head *dir_block = NULL;
2538         struct ext4_dir_entry_2 *de;
2539         struct ext4_dir_entry_tail *t;
2540         ext4_lblk_t block = 0;
2541         unsigned int blocksize = dir->i_sb->s_blocksize;
2542         int csum_size = 0;
2543         int err;
2544
2545         if (ext4_has_metadata_csum(dir->i_sb))
2546                 csum_size = sizeof(struct ext4_dir_entry_tail);
2547
2548         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2549                 err = ext4_try_create_inline_dir(handle, dir, inode);
2550                 if (err < 0 && err != -ENOSPC)
2551                         goto out;
2552                 if (!err)
2553                         goto out;
2554         }
2555
2556         inode->i_size = 0;
2557         dir_block = ext4_append(handle, inode, &block);
2558         if (IS_ERR(dir_block))
2559                 return PTR_ERR(dir_block);
2560         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2561         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2562         set_nlink(inode, 2);
2563         if (csum_size) {
2564                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2565                 initialize_dirent_tail(t, blocksize);
2566         }
2567
2568         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2569         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2570         if (err)
2571                 goto out;
2572         set_buffer_verified(dir_block);
2573 out:
2574         brelse(dir_block);
2575         return err;
2576 }
2577
2578 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2579 {
2580         handle_t *handle;
2581         struct inode *inode;
2582         int err, credits, retries = 0;
2583
2584         if (EXT4_DIR_LINK_MAX(dir))
2585                 return -EMLINK;
2586
2587         err = dquot_initialize(dir);
2588         if (err)
2589                 return err;
2590
2591         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2592                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2593 retry:
2594         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2595                                             &dentry->d_name,
2596                                             0, NULL, EXT4_HT_DIR, credits);
2597         handle = ext4_journal_current_handle();
2598         err = PTR_ERR(inode);
2599         if (IS_ERR(inode))
2600                 goto out_stop;
2601
2602         inode->i_op = &ext4_dir_inode_operations;
2603         inode->i_fop = &ext4_dir_operations;
2604         err = ext4_init_new_dir(handle, dir, inode);
2605         if (err)
2606                 goto out_clear_inode;
2607         err = ext4_mark_inode_dirty(handle, inode);
2608         if (!err)
2609                 err = ext4_add_entry(handle, dentry, inode);
2610         if (err) {
2611 out_clear_inode:
2612                 clear_nlink(inode);
2613                 unlock_new_inode(inode);
2614                 ext4_mark_inode_dirty(handle, inode);
2615                 iput(inode);
2616                 goto out_stop;
2617         }
2618         ext4_inc_count(handle, dir);
2619         ext4_update_dx_flag(dir);
2620         err = ext4_mark_inode_dirty(handle, dir);
2621         if (err)
2622                 goto out_clear_inode;
2623         unlock_new_inode(inode);
2624         d_instantiate(dentry, inode);
2625         if (IS_DIRSYNC(dir))
2626                 ext4_handle_sync(handle);
2627
2628 out_stop:
2629         if (handle)
2630                 ext4_journal_stop(handle);
2631         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2632                 goto retry;
2633         return err;
2634 }
2635
2636 /*
2637  * routine to check that the specified directory is empty (for rmdir)
2638  */
2639 bool ext4_empty_dir(struct inode *inode)
2640 {
2641         unsigned int offset;
2642         struct buffer_head *bh;
2643         struct ext4_dir_entry_2 *de, *de1;
2644         struct super_block *sb;
2645
2646         if (ext4_has_inline_data(inode)) {
2647                 int has_inline_data = 1;
2648                 int ret;
2649
2650                 ret = empty_inline_dir(inode, &has_inline_data);
2651                 if (has_inline_data)
2652                         return ret;
2653         }
2654
2655         sb = inode->i_sb;
2656         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2657                 EXT4_ERROR_INODE(inode, "invalid size");
2658                 return true;
2659         }
2660         bh = ext4_read_dirblock(inode, 0, EITHER);
2661         if (IS_ERR(bh))
2662                 return true;
2663
2664         de = (struct ext4_dir_entry_2 *) bh->b_data;
2665         de1 = ext4_next_entry(de, sb->s_blocksize);
2666         if (le32_to_cpu(de->inode) != inode->i_ino ||
2667                         le32_to_cpu(de1->inode) == 0 ||
2668                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2669                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2670                 brelse(bh);
2671                 return true;
2672         }
2673         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2674                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2675         de = ext4_next_entry(de1, sb->s_blocksize);
2676         while (offset < inode->i_size) {
2677                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2678                         unsigned int lblock;
2679                         brelse(bh);
2680                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2681                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2682                         if (IS_ERR(bh))
2683                                 return true;
2684                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2685                 }
2686                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2687                                          bh->b_data, bh->b_size, offset)) {
2688                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2689                                                          sb->s_blocksize);
2690                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2691                         continue;
2692                 }
2693                 if (le32_to_cpu(de->inode)) {
2694                         brelse(bh);
2695                         return false;
2696                 }
2697                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2698                 de = ext4_next_entry(de, sb->s_blocksize);
2699         }
2700         brelse(bh);
2701         return true;
2702 }
2703
2704 /*
2705  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2706  * such inodes, starting at the superblock, in case we crash before the
2707  * file is closed/deleted, or in case the inode truncate spans multiple
2708  * transactions and the last transaction is not recovered after a crash.
2709  *
2710  * At filesystem recovery time, we walk this list deleting unlinked
2711  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2712  *
2713  * Orphan list manipulation functions must be called under i_mutex unless
2714  * we are just creating the inode or deleting it.
2715  */
2716 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2717 {
2718         struct super_block *sb = inode->i_sb;
2719         struct ext4_sb_info *sbi = EXT4_SB(sb);
2720         struct ext4_iloc iloc;
2721         int err = 0, rc;
2722         bool dirty = false;
2723
2724         if (!sbi->s_journal || is_bad_inode(inode))
2725                 return 0;
2726
2727         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2728                      !inode_is_locked(inode));
2729         /*
2730          * Exit early if inode already is on orphan list. This is a big speedup
2731          * since we don't have to contend on the global s_orphan_lock.
2732          */
2733         if (!list_empty(&EXT4_I(inode)->i_orphan))
2734                 return 0;
2735
2736         /*
2737          * Orphan handling is only valid for files with data blocks
2738          * being truncated, or files being unlinked. Note that we either
2739          * hold i_mutex, or the inode can not be referenced from outside,
2740          * so i_nlink should not be bumped due to race
2741          */
2742         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2743                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2744
2745         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2746         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2747         if (err)
2748                 goto out;
2749
2750         err = ext4_reserve_inode_write(handle, inode, &iloc);
2751         if (err)
2752                 goto out;
2753
2754         mutex_lock(&sbi->s_orphan_lock);
2755         /*
2756          * Due to previous errors inode may be already a part of on-disk
2757          * orphan list. If so skip on-disk list modification.
2758          */
2759         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2760             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2761                 /* Insert this inode at the head of the on-disk orphan list */
2762                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2763                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2764                 dirty = true;
2765         }
2766         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2767         mutex_unlock(&sbi->s_orphan_lock);
2768
2769         if (dirty) {
2770                 err = ext4_handle_dirty_super(handle, sb);
2771                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2772                 if (!err)
2773                         err = rc;
2774                 if (err) {
2775                         /*
2776                          * We have to remove inode from in-memory list if
2777                          * addition to on disk orphan list failed. Stray orphan
2778                          * list entries can cause panics at unmount time.
2779                          */
2780                         mutex_lock(&sbi->s_orphan_lock);
2781                         list_del_init(&EXT4_I(inode)->i_orphan);
2782                         mutex_unlock(&sbi->s_orphan_lock);
2783                 }
2784         }
2785         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2786         jbd_debug(4, "orphan inode %lu will point to %d\n",
2787                         inode->i_ino, NEXT_ORPHAN(inode));
2788 out:
2789         ext4_std_error(sb, err);
2790         return err;
2791 }
2792
2793 /*
2794  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2795  * of such inodes stored on disk, because it is finally being cleaned up.
2796  */
2797 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2798 {
2799         struct list_head *prev;
2800         struct ext4_inode_info *ei = EXT4_I(inode);
2801         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2802         __u32 ino_next;
2803         struct ext4_iloc iloc;
2804         int err = 0;
2805
2806         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2807                 return 0;
2808
2809         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2810                      !inode_is_locked(inode));
2811         /* Do this quick check before taking global s_orphan_lock. */
2812         if (list_empty(&ei->i_orphan))
2813                 return 0;
2814
2815         if (handle) {
2816                 /* Grab inode buffer early before taking global s_orphan_lock */
2817                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2818         }
2819
2820         mutex_lock(&sbi->s_orphan_lock);
2821         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2822
2823         prev = ei->i_orphan.prev;
2824         list_del_init(&ei->i_orphan);
2825
2826         /* If we're on an error path, we may not have a valid
2827          * transaction handle with which to update the orphan list on
2828          * disk, but we still need to remove the inode from the linked
2829          * list in memory. */
2830         if (!handle || err) {
2831                 mutex_unlock(&sbi->s_orphan_lock);
2832                 goto out_err;
2833         }
2834
2835         ino_next = NEXT_ORPHAN(inode);
2836         if (prev == &sbi->s_orphan) {
2837                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2838                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2839                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2840                 if (err) {
2841                         mutex_unlock(&sbi->s_orphan_lock);
2842                         goto out_brelse;
2843                 }
2844                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2845                 mutex_unlock(&sbi->s_orphan_lock);
2846                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2847         } else {
2848                 struct ext4_iloc iloc2;
2849                 struct inode *i_prev =
2850                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2851
2852                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2853                           i_prev->i_ino, ino_next);
2854                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2855                 if (err) {
2856                         mutex_unlock(&sbi->s_orphan_lock);
2857                         goto out_brelse;
2858                 }
2859                 NEXT_ORPHAN(i_prev) = ino_next;
2860                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2861                 mutex_unlock(&sbi->s_orphan_lock);
2862         }
2863         if (err)
2864                 goto out_brelse;
2865         NEXT_ORPHAN(inode) = 0;
2866         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2867 out_err:
2868         ext4_std_error(inode->i_sb, err);
2869         return err;
2870
2871 out_brelse:
2872         brelse(iloc.bh);
2873         goto out_err;
2874 }
2875
2876 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2877 {
2878         int retval;
2879         struct inode *inode;
2880         struct buffer_head *bh;
2881         struct ext4_dir_entry_2 *de;
2882         handle_t *handle = NULL;
2883
2884         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2885                 return -EIO;
2886
2887         /* Initialize quotas before so that eventual writes go in
2888          * separate transaction */
2889         retval = dquot_initialize(dir);
2890         if (retval)
2891                 return retval;
2892         retval = dquot_initialize(d_inode(dentry));
2893         if (retval)
2894                 return retval;
2895
2896         retval = -ENOENT;
2897         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2898         if (IS_ERR(bh))
2899                 return PTR_ERR(bh);
2900         if (!bh)
2901                 goto end_rmdir;
2902
2903         inode = d_inode(dentry);
2904
2905         retval = -EFSCORRUPTED;
2906         if (le32_to_cpu(de->inode) != inode->i_ino)
2907                 goto end_rmdir;
2908
2909         retval = -ENOTEMPTY;
2910         if (!ext4_empty_dir(inode))
2911                 goto end_rmdir;
2912
2913         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2914                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2915         if (IS_ERR(handle)) {
2916                 retval = PTR_ERR(handle);
2917                 handle = NULL;
2918                 goto end_rmdir;
2919         }
2920
2921         if (IS_DIRSYNC(dir))
2922                 ext4_handle_sync(handle);
2923
2924         retval = ext4_delete_entry(handle, dir, de, bh);
2925         if (retval)
2926                 goto end_rmdir;
2927         if (!EXT4_DIR_LINK_EMPTY(inode))
2928                 ext4_warning_inode(inode,
2929                              "empty directory '%.*s' has too many links (%u)",
2930                              dentry->d_name.len, dentry->d_name.name,
2931                              inode->i_nlink);
2932         inode->i_version++;
2933         clear_nlink(inode);
2934         /* There's no need to set i_disksize: the fact that i_nlink is
2935          * zero will ensure that the right thing happens during any
2936          * recovery. */
2937         inode->i_size = 0;
2938         ext4_orphan_add(handle, inode);
2939         inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2940         ext4_mark_inode_dirty(handle, inode);
2941         ext4_dec_count(handle, dir);
2942         ext4_update_dx_flag(dir);
2943         ext4_mark_inode_dirty(handle, dir);
2944
2945 end_rmdir:
2946         brelse(bh);
2947         if (handle)
2948                 ext4_journal_stop(handle);
2949         return retval;
2950 }
2951
2952 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2953 {
2954         int retval;
2955         struct inode *inode;
2956         struct buffer_head *bh;
2957         struct ext4_dir_entry_2 *de;
2958         handle_t *handle = NULL;
2959
2960         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2961                 return -EIO;
2962
2963         trace_ext4_unlink_enter(dir, dentry);
2964         /* Initialize quotas before so that eventual writes go
2965          * in separate transaction */
2966         retval = dquot_initialize(dir);
2967         if (retval)
2968                 return retval;
2969         retval = dquot_initialize(d_inode(dentry));
2970         if (retval)
2971                 return retval;
2972
2973         retval = -ENOENT;
2974         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2975         if (IS_ERR(bh))
2976                 return PTR_ERR(bh);
2977         if (!bh)
2978                 goto end_unlink;
2979
2980         inode = d_inode(dentry);
2981
2982         retval = -EFSCORRUPTED;
2983         if (le32_to_cpu(de->inode) != inode->i_ino)
2984                 goto end_unlink;
2985
2986         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2987                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2988         if (IS_ERR(handle)) {
2989                 retval = PTR_ERR(handle);
2990                 handle = NULL;
2991                 goto end_unlink;
2992         }
2993
2994         if (IS_DIRSYNC(dir))
2995                 ext4_handle_sync(handle);
2996
2997         if (inode->i_nlink == 0) {
2998                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
2999                                    dentry->d_name.len, dentry->d_name.name);
3000                 set_nlink(inode, 1);
3001         }
3002         retval = ext4_delete_entry(handle, dir, de, bh);
3003         if (retval)
3004                 goto end_unlink;
3005         dir->i_ctime = dir->i_mtime = current_time(dir);
3006         ext4_update_dx_flag(dir);
3007         ext4_mark_inode_dirty(handle, dir);
3008         drop_nlink(inode);
3009         if (!inode->i_nlink)
3010                 ext4_orphan_add(handle, inode);
3011         inode->i_ctime = current_time(inode);
3012         ext4_mark_inode_dirty(handle, inode);
3013
3014 end_unlink:
3015         brelse(bh);
3016         if (handle)
3017                 ext4_journal_stop(handle);
3018         trace_ext4_unlink_exit(dentry, retval);
3019         return retval;
3020 }
3021
3022 static int ext4_symlink(struct inode *dir,
3023                         struct dentry *dentry, const char *symname)
3024 {
3025         handle_t *handle;
3026         struct inode *inode;
3027         int err, len = strlen(symname);
3028         int credits;
3029         bool encryption_required;
3030         struct fscrypt_str disk_link;
3031         struct fscrypt_symlink_data *sd = NULL;
3032
3033         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3034                 return -EIO;
3035
3036         disk_link.len = len + 1;
3037         disk_link.name = (char *) symname;
3038
3039         encryption_required = (ext4_encrypted_inode(dir) ||
3040                                DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
3041         if (encryption_required) {
3042                 err = fscrypt_get_encryption_info(dir);
3043                 if (err)
3044                         return err;
3045                 if (!fscrypt_has_encryption_key(dir))
3046                         return -ENOKEY;
3047                 disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
3048                                  sizeof(struct fscrypt_symlink_data));
3049                 sd = kzalloc(disk_link.len, GFP_KERNEL);
3050                 if (!sd)
3051                         return -ENOMEM;
3052         }
3053
3054         if (disk_link.len > dir->i_sb->s_blocksize) {
3055                 err = -ENAMETOOLONG;
3056                 goto err_free_sd;
3057         }
3058
3059         err = dquot_initialize(dir);
3060         if (err)
3061                 goto err_free_sd;
3062
3063         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3064                 /*
3065                  * For non-fast symlinks, we just allocate inode and put it on
3066                  * orphan list in the first transaction => we need bitmap,
3067                  * group descriptor, sb, inode block, quota blocks, and
3068                  * possibly selinux xattr blocks.
3069                  */
3070                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3071                           EXT4_XATTR_TRANS_BLOCKS;
3072         } else {
3073                 /*
3074                  * Fast symlink. We have to add entry to directory
3075                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3076                  * allocate new inode (bitmap, group descriptor, inode block,
3077                  * quota blocks, sb is already counted in previous macros).
3078                  */
3079                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3080                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3081         }
3082
3083         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3084                                             &dentry->d_name, 0, NULL,
3085                                             EXT4_HT_DIR, credits);
3086         handle = ext4_journal_current_handle();
3087         if (IS_ERR(inode)) {
3088                 if (handle)
3089                         ext4_journal_stop(handle);
3090                 err = PTR_ERR(inode);
3091                 goto err_free_sd;
3092         }
3093
3094         if (encryption_required) {
3095                 struct qstr istr;
3096                 struct fscrypt_str ostr =
3097                         FSTR_INIT(sd->encrypted_path, disk_link.len);
3098
3099                 istr.name = (const unsigned char *) symname;
3100                 istr.len = len;
3101                 err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
3102                 if (err)
3103                         goto err_drop_inode;
3104                 sd->len = cpu_to_le16(ostr.len);
3105                 disk_link.name = (char *) sd;
3106                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3107         }
3108
3109         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3110                 if (!encryption_required)
3111                         inode->i_op = &ext4_symlink_inode_operations;
3112                 inode_nohighmem(inode);
3113                 ext4_set_aops(inode);
3114                 /*
3115                  * We cannot call page_symlink() with transaction started
3116                  * because it calls into ext4_write_begin() which can wait
3117                  * for transaction commit if we are running out of space
3118                  * and thus we deadlock. So we have to stop transaction now
3119                  * and restart it when symlink contents is written.
3120                  *
3121                  * To keep fs consistent in case of crash, we have to put inode
3122                  * to orphan list in the mean time.
3123                  */
3124                 drop_nlink(inode);
3125                 err = ext4_orphan_add(handle, inode);
3126                 ext4_journal_stop(handle);
3127                 handle = NULL;
3128                 if (err)
3129                         goto err_drop_inode;
3130                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3131                 if (err)
3132                         goto err_drop_inode;
3133                 /*
3134                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3135                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3136                  */
3137                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3138                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3139                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3140                 if (IS_ERR(handle)) {
3141                         err = PTR_ERR(handle);
3142                         handle = NULL;
3143                         goto err_drop_inode;
3144                 }
3145                 set_nlink(inode, 1);
3146                 err = ext4_orphan_del(handle, inode);
3147                 if (err)
3148                         goto err_drop_inode;
3149         } else {
3150                 /* clear the extent format for fast symlink */
3151                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3152                 if (!encryption_required) {
3153                         inode->i_op = &ext4_fast_symlink_inode_operations;
3154                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3155                 }
3156                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3157                        disk_link.len);
3158                 inode->i_size = disk_link.len - 1;
3159         }
3160         EXT4_I(inode)->i_disksize = inode->i_size;
3161         err = ext4_add_nondir(handle, dentry, inode);
3162         if (!err && IS_DIRSYNC(dir))
3163                 ext4_handle_sync(handle);
3164
3165         if (handle)
3166                 ext4_journal_stop(handle);
3167         kfree(sd);
3168         return err;
3169 err_drop_inode:
3170         if (handle)
3171                 ext4_journal_stop(handle);
3172         clear_nlink(inode);
3173         unlock_new_inode(inode);
3174         iput(inode);
3175 err_free_sd:
3176         kfree(sd);
3177         return err;
3178 }
3179
3180 static int ext4_link(struct dentry *old_dentry,
3181                      struct inode *dir, struct dentry *dentry)
3182 {
3183         handle_t *handle;
3184         struct inode *inode = d_inode(old_dentry);
3185         int err, retries = 0;
3186
3187         if (inode->i_nlink >= EXT4_LINK_MAX)
3188                 return -EMLINK;
3189         if (ext4_encrypted_inode(dir) &&
3190                         !fscrypt_has_permitted_context(dir, inode))
3191                 return -EPERM;
3192
3193        if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3194            (!projid_eq(EXT4_I(dir)->i_projid,
3195                        EXT4_I(old_dentry->d_inode)->i_projid)))
3196                 return -EXDEV;
3197
3198         err = dquot_initialize(dir);
3199         if (err)
3200                 return err;
3201
3202 retry:
3203         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3204                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3205                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3206         if (IS_ERR(handle))
3207                 return PTR_ERR(handle);
3208
3209         if (IS_DIRSYNC(dir))
3210                 ext4_handle_sync(handle);
3211
3212         inode->i_ctime = current_time(inode);
3213         ext4_inc_count(handle, inode);
3214         ihold(inode);
3215
3216         err = ext4_add_entry(handle, dentry, inode);
3217         if (!err) {
3218                 ext4_mark_inode_dirty(handle, inode);
3219                 /* this can happen only for tmpfile being
3220                  * linked the first time
3221                  */
3222                 if (inode->i_nlink == 1)
3223                         ext4_orphan_del(handle, inode);
3224                 d_instantiate(dentry, inode);
3225         } else {
3226                 drop_nlink(inode);
3227                 iput(inode);
3228         }
3229         ext4_journal_stop(handle);
3230         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3231                 goto retry;
3232         return err;
3233 }
3234
3235
3236 /*
3237  * Try to find buffer head where contains the parent block.
3238  * It should be the inode block if it is inlined or the 1st block
3239  * if it is a normal dir.
3240  */
3241 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3242                                         struct inode *inode,
3243                                         int *retval,
3244                                         struct ext4_dir_entry_2 **parent_de,
3245                                         int *inlined)
3246 {
3247         struct buffer_head *bh;
3248
3249         if (!ext4_has_inline_data(inode)) {
3250                 bh = ext4_read_dirblock(inode, 0, EITHER);
3251                 if (IS_ERR(bh)) {
3252                         *retval = PTR_ERR(bh);
3253                         return NULL;
3254                 }
3255                 *parent_de = ext4_next_entry(
3256                                         (struct ext4_dir_entry_2 *)bh->b_data,
3257                                         inode->i_sb->s_blocksize);
3258                 return bh;
3259         }
3260
3261         *inlined = 1;
3262         return ext4_get_first_inline_block(inode, parent_de, retval);
3263 }
3264
3265 struct ext4_renament {
3266         struct inode *dir;
3267         struct dentry *dentry;
3268         struct inode *inode;
3269         bool is_dir;
3270         int dir_nlink_delta;
3271
3272         /* entry for "dentry" */
3273         struct buffer_head *bh;
3274         struct ext4_dir_entry_2 *de;
3275         int inlined;
3276
3277         /* entry for ".." in inode if it's a directory */
3278         struct buffer_head *dir_bh;
3279         struct ext4_dir_entry_2 *parent_de;
3280         int dir_inlined;
3281 };
3282
3283 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3284 {
3285         int retval;
3286
3287         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3288                                               &retval, &ent->parent_de,
3289                                               &ent->dir_inlined);
3290         if (!ent->dir_bh)
3291                 return retval;
3292         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3293                 return -EFSCORRUPTED;
3294         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3295         return ext4_journal_get_write_access(handle, ent->dir_bh);
3296 }
3297
3298 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3299                                   unsigned dir_ino)
3300 {
3301         int retval;
3302
3303         ent->parent_de->inode = cpu_to_le32(dir_ino);
3304         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3305         if (!ent->dir_inlined) {
3306                 if (is_dx(ent->inode)) {
3307                         retval = ext4_handle_dirty_dx_node(handle,
3308                                                            ent->inode,
3309                                                            ent->dir_bh);
3310                 } else {
3311                         retval = ext4_handle_dirty_dirent_node(handle,
3312                                                                ent->inode,
3313                                                                ent->dir_bh);
3314                 }
3315         } else {
3316                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3317         }
3318         if (retval) {
3319                 ext4_std_error(ent->dir->i_sb, retval);
3320                 return retval;
3321         }
3322         return 0;
3323 }
3324
3325 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3326                        unsigned ino, unsigned file_type)
3327 {
3328         int retval;
3329
3330         BUFFER_TRACE(ent->bh, "get write access");
3331         retval = ext4_journal_get_write_access(handle, ent->bh);
3332         if (retval)
3333                 return retval;
3334         ent->de->inode = cpu_to_le32(ino);
3335         if (ext4_has_feature_filetype(ent->dir->i_sb))
3336                 ent->de->file_type = file_type;
3337         ent->dir->i_version++;
3338         ent->dir->i_ctime = ent->dir->i_mtime =
3339                 current_time(ent->dir);
3340         ext4_mark_inode_dirty(handle, ent->dir);
3341         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3342         if (!ent->inlined) {
3343                 retval = ext4_handle_dirty_dirent_node(handle,
3344                                                        ent->dir, ent->bh);
3345                 if (unlikely(retval)) {
3346                         ext4_std_error(ent->dir->i_sb, retval);
3347                         return retval;
3348                 }
3349         }
3350         brelse(ent->bh);
3351         ent->bh = NULL;
3352
3353         return 0;
3354 }
3355
3356 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3357                                   const struct qstr *d_name)
3358 {
3359         int retval = -ENOENT;
3360         struct buffer_head *bh;
3361         struct ext4_dir_entry_2 *de;
3362
3363         bh = ext4_find_entry(dir, d_name, &de, NULL);
3364         if (IS_ERR(bh))
3365                 return PTR_ERR(bh);
3366         if (bh) {
3367                 retval = ext4_delete_entry(handle, dir, de, bh);
3368                 brelse(bh);
3369         }
3370         return retval;
3371 }
3372
3373 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3374                                int force_reread)
3375 {
3376         int retval;
3377         /*
3378          * ent->de could have moved from under us during htree split, so make
3379          * sure that we are deleting the right entry.  We might also be pointing
3380          * to a stale entry in the unused part of ent->bh so just checking inum
3381          * and the name isn't enough.
3382          */
3383         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3384             ent->de->name_len != ent->dentry->d_name.len ||
3385             strncmp(ent->de->name, ent->dentry->d_name.name,
3386                     ent->de->name_len) ||
3387             force_reread) {
3388                 retval = ext4_find_delete_entry(handle, ent->dir,
3389                                                 &ent->dentry->d_name);
3390         } else {
3391                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3392                 if (retval == -ENOENT) {
3393                         retval = ext4_find_delete_entry(handle, ent->dir,
3394                                                         &ent->dentry->d_name);
3395                 }
3396         }
3397
3398         if (retval) {
3399                 ext4_warning_inode(ent->dir,
3400                                    "Deleting old file: nlink %d, error=%d",
3401                                    ent->dir->i_nlink, retval);
3402         }
3403 }
3404
3405 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3406 {
3407         if (ent->dir_nlink_delta) {
3408                 if (ent->dir_nlink_delta == -1)
3409                         ext4_dec_count(handle, ent->dir);
3410                 else
3411                         ext4_inc_count(handle, ent->dir);
3412                 ext4_mark_inode_dirty(handle, ent->dir);
3413         }
3414 }
3415
3416 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3417                                               int credits, handle_t **h)
3418 {
3419         struct inode *wh;
3420         handle_t *handle;
3421         int retries = 0;
3422
3423         /*
3424          * for inode block, sb block, group summaries,
3425          * and inode bitmap
3426          */
3427         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3428                     EXT4_XATTR_TRANS_BLOCKS + 4);
3429 retry:
3430         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3431                                          &ent->dentry->d_name, 0, NULL,
3432                                          EXT4_HT_DIR, credits);
3433
3434         handle = ext4_journal_current_handle();
3435         if (IS_ERR(wh)) {
3436                 if (handle)
3437                         ext4_journal_stop(handle);
3438                 if (PTR_ERR(wh) == -ENOSPC &&
3439                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3440                         goto retry;
3441         } else {
3442                 *h = handle;
3443                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3444                 wh->i_op = &ext4_special_inode_operations;
3445         }
3446         return wh;
3447 }
3448
3449 /*
3450  * Anybody can rename anything with this: the permission checks are left to the
3451  * higher-level routines.
3452  *
3453  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3454  * while new_{dentry,inode) refers to the destination dentry/inode
3455  * This comes from rename(const char *oldpath, const char *newpath)
3456  */
3457 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3458                        struct inode *new_dir, struct dentry *new_dentry,
3459                        unsigned int flags)
3460 {
3461         handle_t *handle = NULL;
3462         struct ext4_renament old = {
3463                 .dir = old_dir,
3464                 .dentry = old_dentry,
3465                 .inode = d_inode(old_dentry),
3466         };
3467         struct ext4_renament new = {
3468                 .dir = new_dir,
3469                 .dentry = new_dentry,
3470                 .inode = d_inode(new_dentry),
3471         };
3472         int force_reread;
3473         int retval;
3474         struct inode *whiteout = NULL;
3475         int credits;
3476         u8 old_file_type;
3477
3478         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3479             (!projid_eq(EXT4_I(new_dir)->i_projid,
3480                         EXT4_I(old_dentry->d_inode)->i_projid)))
3481                 return -EXDEV;
3482
3483         if ((ext4_encrypted_inode(old_dir) &&
3484              !fscrypt_has_encryption_key(old_dir)) ||
3485             (ext4_encrypted_inode(new_dir) &&
3486              !fscrypt_has_encryption_key(new_dir)))
3487                 return -ENOKEY;
3488
3489         retval = dquot_initialize(old.dir);
3490         if (retval)
3491                 return retval;
3492         retval = dquot_initialize(new.dir);
3493         if (retval)
3494                 return retval;
3495
3496         /* Initialize quotas before so that eventual writes go
3497          * in separate transaction */
3498         if (new.inode) {
3499                 retval = dquot_initialize(new.inode);
3500                 if (retval)
3501                         return retval;
3502         }
3503
3504         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3505         if (IS_ERR(old.bh))
3506                 return PTR_ERR(old.bh);
3507         /*
3508          *  Check for inode number is _not_ due to possible IO errors.
3509          *  We might rmdir the source, keep it as pwd of some process
3510          *  and merrily kill the link to whatever was created under the
3511          *  same name. Goodbye sticky bit ;-<
3512          */
3513         retval = -ENOENT;
3514         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3515                 goto end_rename;
3516
3517         if ((old.dir != new.dir) &&
3518             ext4_encrypted_inode(new.dir) &&
3519             !fscrypt_has_permitted_context(new.dir, old.inode)) {
3520                 retval = -EPERM;
3521                 goto end_rename;
3522         }
3523
3524         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3525                                  &new.de, &new.inlined);
3526         if (IS_ERR(new.bh)) {
3527                 retval = PTR_ERR(new.bh);
3528                 new.bh = NULL;
3529                 goto end_rename;
3530         }
3531         if (new.bh) {
3532                 if (!new.inode) {
3533                         brelse(new.bh);
3534                         new.bh = NULL;
3535                 }
3536         }
3537         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3538                 ext4_alloc_da_blocks(old.inode);
3539
3540         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3541                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3542         if (!(flags & RENAME_WHITEOUT)) {
3543                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3544                 if (IS_ERR(handle)) {
3545                         retval = PTR_ERR(handle);
3546                         handle = NULL;
3547                         goto end_rename;
3548                 }
3549         } else {
3550                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3551                 if (IS_ERR(whiteout)) {
3552                         retval = PTR_ERR(whiteout);
3553                         whiteout = NULL;
3554                         goto end_rename;
3555                 }
3556         }
3557
3558         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3559                 ext4_handle_sync(handle);
3560
3561         if (S_ISDIR(old.inode->i_mode)) {
3562                 if (new.inode) {
3563                         retval = -ENOTEMPTY;
3564                         if (!ext4_empty_dir(new.inode))
3565                                 goto end_rename;
3566                 } else {
3567                         retval = -EMLINK;
3568                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3569                                 goto end_rename;
3570                 }
3571                 retval = ext4_rename_dir_prepare(handle, &old);
3572                 if (retval)
3573                         goto end_rename;
3574         }
3575         /*
3576          * If we're renaming a file within an inline_data dir and adding or
3577          * setting the new dirent causes a conversion from inline_data to
3578          * extents/blockmap, we need to force the dirent delete code to
3579          * re-read the directory, or else we end up trying to delete a dirent
3580          * from what is now the extent tree root (or a block map).
3581          */
3582         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3583                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3584
3585         old_file_type = old.de->file_type;
3586         if (whiteout) {
3587                 /*
3588                  * Do this before adding a new entry, so the old entry is sure
3589                  * to be still pointing to the valid old entry.
3590                  */
3591                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3592                                      EXT4_FT_CHRDEV);
3593                 if (retval)
3594                         goto end_rename;
3595                 ext4_mark_inode_dirty(handle, whiteout);
3596         }
3597         if (!new.bh) {
3598                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3599                 if (retval)
3600                         goto end_rename;
3601         } else {
3602                 retval = ext4_setent(handle, &new,
3603                                      old.inode->i_ino, old_file_type);
3604                 if (retval)
3605                         goto end_rename;
3606         }
3607         if (force_reread)
3608                 force_reread = !ext4_test_inode_flag(new.dir,
3609                                                      EXT4_INODE_INLINE_DATA);
3610
3611         /*
3612          * Like most other Unix systems, set the ctime for inodes on a
3613          * rename.
3614          */
3615         old.inode->i_ctime = current_time(old.inode);
3616         ext4_mark_inode_dirty(handle, old.inode);
3617
3618         if (!whiteout) {
3619                 /*
3620                  * ok, that's it
3621                  */
3622                 ext4_rename_delete(handle, &old, force_reread);
3623         }
3624
3625         if (new.inode) {
3626                 ext4_dec_count(handle, new.inode);
3627                 new.inode->i_ctime = current_time(new.inode);
3628         }
3629         old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
3630         ext4_update_dx_flag(old.dir);
3631         if (old.dir_bh) {
3632                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3633                 if (retval)
3634                         goto end_rename;
3635
3636                 ext4_dec_count(handle, old.dir);
3637                 if (new.inode) {
3638                         /* checked ext4_empty_dir above, can't have another
3639                          * parent, ext4_dec_count() won't work for many-linked
3640                          * dirs */
3641                         clear_nlink(new.inode);
3642                 } else {
3643                         ext4_inc_count(handle, new.dir);
3644                         ext4_update_dx_flag(new.dir);
3645                         ext4_mark_inode_dirty(handle, new.dir);
3646                 }
3647         }
3648         ext4_mark_inode_dirty(handle, old.dir);
3649         if (new.inode) {
3650                 ext4_mark_inode_dirty(handle, new.inode);
3651                 if (!new.inode->i_nlink)
3652                         ext4_orphan_add(handle, new.inode);
3653         }
3654         retval = 0;
3655
3656 end_rename:
3657         brelse(old.dir_bh);
3658         brelse(old.bh);
3659         brelse(new.bh);
3660         if (whiteout) {
3661                 if (retval)
3662                         drop_nlink(whiteout);
3663                 unlock_new_inode(whiteout);
3664                 iput(whiteout);
3665         }
3666         if (handle)
3667                 ext4_journal_stop(handle);
3668         return retval;
3669 }
3670
3671 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3672                              struct inode *new_dir, struct dentry *new_dentry)
3673 {
3674         handle_t *handle = NULL;
3675         struct ext4_renament old = {
3676                 .dir = old_dir,
3677                 .dentry = old_dentry,
3678                 .inode = d_inode(old_dentry),
3679         };
3680         struct ext4_renament new = {
3681                 .dir = new_dir,
3682                 .dentry = new_dentry,
3683                 .inode = d_inode(new_dentry),
3684         };
3685         u8 new_file_type;
3686         int retval;
3687         struct timespec ctime;
3688
3689         if ((ext4_encrypted_inode(old_dir) &&
3690              !fscrypt_has_encryption_key(old_dir)) ||
3691             (ext4_encrypted_inode(new_dir) &&
3692              !fscrypt_has_encryption_key(new_dir)))
3693                 return -ENOKEY;
3694
3695         if ((ext4_encrypted_inode(old_dir) ||
3696              ext4_encrypted_inode(new_dir)) &&
3697             (old_dir != new_dir) &&
3698             (!fscrypt_has_permitted_context(new_dir, old.inode) ||
3699              !fscrypt_has_permitted_context(old_dir, new.inode)))
3700                 return -EPERM;
3701
3702         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
3703              !projid_eq(EXT4_I(new_dir)->i_projid,
3704                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
3705             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
3706              !projid_eq(EXT4_I(old_dir)->i_projid,
3707                         EXT4_I(new_dentry->d_inode)->i_projid)))
3708                 return -EXDEV;
3709
3710         retval = dquot_initialize(old.dir);
3711         if (retval)
3712                 return retval;
3713         retval = dquot_initialize(new.dir);
3714         if (retval)
3715                 return retval;
3716
3717         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3718                                  &old.de, &old.inlined);
3719         if (IS_ERR(old.bh))
3720                 return PTR_ERR(old.bh);
3721         /*
3722          *  Check for inode number is _not_ due to possible IO errors.
3723          *  We might rmdir the source, keep it as pwd of some process
3724          *  and merrily kill the link to whatever was created under the
3725          *  same name. Goodbye sticky bit ;-<
3726          */
3727         retval = -ENOENT;
3728         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3729                 goto end_rename;
3730
3731         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3732                                  &new.de, &new.inlined);
3733         if (IS_ERR(new.bh)) {
3734                 retval = PTR_ERR(new.bh);
3735                 new.bh = NULL;
3736                 goto end_rename;
3737         }
3738
3739         /* RENAME_EXCHANGE case: old *and* new must both exist */
3740         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3741                 goto end_rename;
3742
3743         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3744                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3745                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3746         if (IS_ERR(handle)) {
3747                 retval = PTR_ERR(handle);
3748                 handle = NULL;
3749                 goto end_rename;
3750         }
3751
3752         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3753                 ext4_handle_sync(handle);
3754
3755         if (S_ISDIR(old.inode->i_mode)) {
3756                 old.is_dir = true;
3757                 retval = ext4_rename_dir_prepare(handle, &old);
3758                 if (retval)
3759                         goto end_rename;
3760         }
3761         if (S_ISDIR(new.inode->i_mode)) {
3762                 new.is_dir = true;
3763                 retval = ext4_rename_dir_prepare(handle, &new);
3764                 if (retval)
3765                         goto end_rename;
3766         }
3767
3768         /*
3769          * Other than the special case of overwriting a directory, parents'
3770          * nlink only needs to be modified if this is a cross directory rename.
3771          */
3772         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3773                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3774                 new.dir_nlink_delta = -old.dir_nlink_delta;
3775                 retval = -EMLINK;
3776                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3777                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3778                         goto end_rename;
3779         }
3780
3781         new_file_type = new.de->file_type;
3782         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3783         if (retval)
3784                 goto end_rename;
3785
3786         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3787         if (retval)
3788                 goto end_rename;
3789
3790         /*
3791          * Like most other Unix systems, set the ctime for inodes on a
3792          * rename.
3793          */
3794         ctime = current_time(old.inode);
3795         old.inode->i_ctime = ctime;
3796         new.inode->i_ctime = ctime;
3797         ext4_mark_inode_dirty(handle, old.inode);
3798         ext4_mark_inode_dirty(handle, new.inode);
3799
3800         if (old.dir_bh) {
3801                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3802                 if (retval)
3803                         goto end_rename;
3804         }
3805         if (new.dir_bh) {
3806                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3807                 if (retval)
3808                         goto end_rename;
3809         }
3810         ext4_update_dir_count(handle, &old);
3811         ext4_update_dir_count(handle, &new);
3812         retval = 0;
3813
3814 end_rename:
3815         brelse(old.dir_bh);
3816         brelse(new.dir_bh);
3817         brelse(old.bh);
3818         brelse(new.bh);
3819         if (handle)
3820                 ext4_journal_stop(handle);
3821         return retval;
3822 }
3823
3824 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3825                         struct inode *new_dir, struct dentry *new_dentry,
3826                         unsigned int flags)
3827 {
3828         if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
3829                 return -EIO;
3830
3831         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3832                 return -EINVAL;
3833
3834         if (flags & RENAME_EXCHANGE) {
3835                 return ext4_cross_rename(old_dir, old_dentry,
3836                                          new_dir, new_dentry);
3837         }
3838
3839         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3840 }
3841
3842 /*
3843  * directories can handle most operations...
3844  */
3845 const struct inode_operations ext4_dir_inode_operations = {
3846         .create         = ext4_create,
3847         .lookup         = ext4_lookup,
3848         .link           = ext4_link,
3849         .unlink         = ext4_unlink,
3850         .symlink        = ext4_symlink,
3851         .mkdir          = ext4_mkdir,
3852         .rmdir          = ext4_rmdir,
3853         .mknod          = ext4_mknod,
3854         .tmpfile        = ext4_tmpfile,
3855         .rename         = ext4_rename2,
3856         .setattr        = ext4_setattr,
3857         .getattr        = ext4_getattr,
3858         .listxattr      = ext4_listxattr,
3859         .get_acl        = ext4_get_acl,
3860         .set_acl        = ext4_set_acl,
3861         .fiemap         = ext4_fiemap,
3862 };
3863
3864 const struct inode_operations ext4_special_inode_operations = {
3865         .setattr        = ext4_setattr,
3866         .getattr        = ext4_getattr,
3867         .listxattr      = ext4_listxattr,
3868         .get_acl        = ext4_get_acl,
3869         .set_acl        = ext4_set_acl,
3870 };