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/jbd2.h>
  30 #include <linux/time.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/stat.h>
  33 #include <linux/string.h>
  34 #include <linux/quotaops.h>
  35 #include <linux/buffer_head.h>
  36 #include <linux/bio.h>
  37 #include "ext4.h"
  38 #include "ext4_jbd2.h"
  39
  40 #include "xattr.h"
  41 #include "acl.h"
  42
  43 #include <trace/events/ext4.h>
  44 /*
  45  * define how far ahead to read directories while searching them.
  46  */
  47 #define NAMEI_RA_CHUNKS  2
  48 #define NAMEI_RA_BLOCKS  4
  49 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
  50
  51 static struct buffer_head *ext4_append(handle_t *handle,
  52                                         struct inode *inode,
  53                                         ext4_lblk_t *block)
  54 {
  55         struct buffer_head *bh;
  56         int err;
  57
  58         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
  59                      ((inode->i_size >> 10) >=
  60                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
  61                 return ERR_PTR(-ENOSPC);
  62
  63         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
  64
  65         bh = ext4_bread(handle, inode, *block, 1);
  66         if (IS_ERR(bh))
  67                 return bh;
  68         inode->i_size += inode->i_sb->s_blocksize;
  69         EXT4_I(inode)->i_disksize = inode->i_size;
  70         BUFFER_TRACE(bh, "get_write_access");
  71         err = ext4_journal_get_write_access(handle, bh);
  72         if (err) {
  73                 brelse(bh);
  74                 ext4_std_error(inode->i_sb, err);
  75                 return ERR_PTR(err);
  76         }
  77         return bh;
  78 }
  79
  80 static int ext4_dx_csum_verify(struct inode *inode,
  81                                struct ext4_dir_entry *dirent);
  82
  83 typedef enum {
  84         EITHER, INDEX, DIRENT
  85 } dirblock_type_t;
  86
  87 #define ext4_read_dirblock(inode, block, type) \
  88         __ext4_read_dirblock((inode), (block), (type), __LINE__)
  89
  90 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
  91                                               ext4_lblk_t block,
  92                                               dirblock_type_t type,
  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                                "error %ld reading directory block "
 103                                "(ino %lu, block %lu)", PTR_ERR(bh), inode->i_ino,
 104                                (unsigned long) block);
 105
 106                 return bh;
 107         }
 108         if (!bh) {
 109                 ext4_error_inode(inode, __func__, line, block, "Directory hole found");
 110                 return ERR_PTR(-EIO);
 111         }
 112         dirent = (struct ext4_dir_entry *) bh->b_data;
 113         /* Determine whether or not we have an index block */
 114         if (is_dx(inode)) {
 115                 if (block == 0)
 116                         is_dx_block = 1;
 117                 else if (ext4_rec_len_from_disk(dirent->rec_len,
 118                                                 inode->i_sb->s_blocksize) ==
 119                          inode->i_sb->s_blocksize)
 120                         is_dx_block = 1;
 121         }
 122         if (!is_dx_block && type == INDEX) {
 123                 ext4_error_inode(inode, __func__, line, block,
 124                        "directory leaf block found instead of index block");
 125                 return ERR_PTR(-EIO);
 126         }
 127         if (!ext4_has_metadata_csum(inode->i_sb) ||
 128             buffer_verified(bh))
 129                 return bh;
 130
 131         /*
 132          * An empty leaf block can get mistaken for a index block; for
 133          * this reason, we can only check the index checksum when the
 134          * caller is sure it should be an index block.
 135          */
 136         if (is_dx_block && type == INDEX) {
 137                 if (ext4_dx_csum_verify(inode, dirent))
 138                         set_buffer_verified(bh);
 139                 else {
 140                         ext4_error_inode(inode, __func__, line, block,
 141                                 "Directory index failed checksum");
 142                         brelse(bh);
 143                         return ERR_PTR(-EIO);
 144                 }
 145         }
 146         if (!is_dx_block) {
 147                 if (ext4_dirent_csum_verify(inode, dirent))
 148                         set_buffer_verified(bh);
 149                 else {
 150                         ext4_error_inode(inode, __func__, line, block,
 151                                 "Directory block failed checksum");
 152                         brelse(bh);
 153                         return ERR_PTR(-EIO);
 154                 }
 155         }
 156         return bh;
 157 }
 158
 159 #ifndef assert
 160 #define assert(test) J_ASSERT(test)
 161 #endif
 162
 163 #ifdef DX_DEBUG
 164 #define dxtrace(command) command
 165 #else
 166 #define dxtrace(command)
 167 #endif
 168
 169 struct fake_dirent
 170 {
 171         __le32 inode;
 172         __le16 rec_len;
 173         u8 name_len;
 174         u8 file_type;
 175 };
 176
 177 struct dx_countlimit
 178 {
 179         __le16 limit;
 180         __le16 count;
 181 };
 182
 183 struct dx_entry
 184 {
 185         __le32 hash;
 186         __le32 block;
 187 };
 188
 189 /*
 190  * dx_root_info is laid out so that if it should somehow get overlaid by a
 191  * dirent the two low bits of the hash version will be zero.  Therefore, the
 192  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
 193  */
 194
 195 struct dx_root
 196 {
 197         struct fake_dirent dot;
 198         char dot_name[4];
 199         struct fake_dirent dotdot;
 200         char dotdot_name[4];
 201         struct dx_root_info
 202         {
 203                 __le32 reserved_zero;
 204                 u8 hash_version;
 205                 u8 info_length; /* 8 */
 206                 u8 indirect_levels;
 207                 u8 unused_flags;
 208         }
 209         info;
 210         struct dx_entry entries[0];
 211 };
 212
 213 struct dx_node
 214 {
 215         struct fake_dirent fake;
 216         struct dx_entry entries[0];
 217 };
 218
 219
 220 struct dx_frame
 221 {
 222         struct buffer_head *bh;
 223         struct dx_entry *entries;
 224         struct dx_entry *at;
 225 };
 226
 227 struct dx_map_entry
 228 {
 229         u32 hash;
 230         u16 offs;
 231         u16 size;
 232 };
 233
 234 /*
 235  * This goes at the end of each htree block.
 236  */
 237 struct dx_tail {
 238         u32 dt_reserved;
 239         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
 240 };
 241
 242 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
 243 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
 244 static inline unsigned dx_get_hash(struct dx_entry *entry);
 245 static void dx_set_hash(struct dx_entry *entry, unsigned value);
 246 static unsigned dx_get_count(struct dx_entry *entries);
 247 static unsigned dx_get_limit(struct dx_entry *entries);
 248 static void dx_set_count(struct dx_entry *entries, unsigned value);
 249 static void dx_set_limit(struct dx_entry *entries, unsigned value);
 250 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
 251 static unsigned dx_node_limit(struct inode *dir);
 252 static struct dx_frame *dx_probe(const struct qstr *d_name,
 253                                  struct inode *dir,
 254                                  struct dx_hash_info *hinfo,
 255                                  struct dx_frame *frame);
 256 static void dx_release(struct dx_frame *frames);
 257 static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
 258                        struct dx_hash_info *hinfo, struct dx_map_entry map[]);
 259 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
 260 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
 261                 struct dx_map_entry *offsets, int count, unsigned blocksize);
 262 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
 263 static void dx_insert_block(struct dx_frame *frame,
 264                                         u32 hash, ext4_lblk_t block);
 265 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 266                                  struct dx_frame *frame,
 267                                  struct dx_frame *frames,
 268                                  __u32 *start_hash);
 269 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 270                 const struct qstr *d_name,
 271                 struct ext4_dir_entry_2 **res_dir);
 272 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
 273                              struct inode *inode);
 274
 275 /* checksumming functions */
 276 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
 277                             unsigned int blocksize)
 278 {
 279         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
 280         t->det_rec_len = ext4_rec_len_to_disk(
 281                         sizeof(struct ext4_dir_entry_tail), blocksize);
 282         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
 283 }
 284
 285 /* Walk through a dirent block to find a checksum "dirent" at the tail */
 286 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
 287                                                    struct ext4_dir_entry *de)
 288 {
 289         struct ext4_dir_entry_tail *t;
 290
 291 #ifdef PARANOID
 292         struct ext4_dir_entry *d, *top;
 293
 294         d = de;
 295         top = (struct ext4_dir_entry *)(((void *)de) +
 296                 (EXT4_BLOCK_SIZE(inode->i_sb) -
 297                 sizeof(struct ext4_dir_entry_tail)));
 298         while (d < top && d->rec_len)
 299                 d = (struct ext4_dir_entry *)(((void *)d) +
 300                     le16_to_cpu(d->rec_len));
 301
 302         if (d != top)
 303                 return NULL;
 304
 305         t = (struct ext4_dir_entry_tail *)d;
 306 #else
 307         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
 308 #endif
 309
 310         if (t->det_reserved_zero1 ||
 311             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
 312             t->det_reserved_zero2 ||
 313             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
 314                 return NULL;
 315
 316         return t;
 317 }
 318
 319 static __le32 ext4_dirent_csum(struct inode *inode,
 320                                struct ext4_dir_entry *dirent, int size)
 321 {
 322         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 323         struct ext4_inode_info *ei = EXT4_I(inode);
 324         __u32 csum;
 325
 326         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 327         return cpu_to_le32(csum);
 328 }
 329
 330 static void warn_no_space_for_csum(struct inode *inode)
 331 {
 332         ext4_warning(inode->i_sb, "no space in directory inode %lu leaf for "
 333                      "checksum.  Please run e2fsck -D.", inode->i_ino);
 334 }
 335
 336 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
 337 {
 338         struct ext4_dir_entry_tail *t;
 339
 340         if (!ext4_has_metadata_csum(inode->i_sb))
 341                 return 1;
 342
 343         t = get_dirent_tail(inode, dirent);
 344         if (!t) {
 345                 warn_no_space_for_csum(inode);
 346                 return 0;
 347         }
 348
 349         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
 350                                                 (void *)t - (void *)dirent))
 351                 return 0;
 352
 353         return 1;
 354 }
 355
 356 static void ext4_dirent_csum_set(struct inode *inode,
 357                                  struct ext4_dir_entry *dirent)
 358 {
 359         struct ext4_dir_entry_tail *t;
 360
 361         if (!ext4_has_metadata_csum(inode->i_sb))
 362                 return;
 363
 364         t = get_dirent_tail(inode, dirent);
 365         if (!t) {
 366                 warn_no_space_for_csum(inode);
 367                 return;
 368         }
 369
 370         t->det_checksum = ext4_dirent_csum(inode, dirent,
 371                                            (void *)t - (void *)dirent);
 372 }
 373
 374 int ext4_handle_dirty_dirent_node(handle_t *handle,
 375                                   struct inode *inode,
 376                                   struct buffer_head *bh)
 377 {
 378         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 379         return ext4_handle_dirty_metadata(handle, inode, bh);
 380 }
 381
 382 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
 383                                                struct ext4_dir_entry *dirent,
 384                                                int *offset)
 385 {
 386         struct ext4_dir_entry *dp;
 387         struct dx_root_info *root;
 388         int count_offset;
 389
 390         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
 391                 count_offset = 8;
 392         else if (le16_to_cpu(dirent->rec_len) == 12) {
 393                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
 394                 if (le16_to_cpu(dp->rec_len) !=
 395                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
 396                         return NULL;
 397                 root = (struct dx_root_info *)(((void *)dp + 12));
 398                 if (root->reserved_zero ||
 399                     root->info_length != sizeof(struct dx_root_info))
 400                         return NULL;
 401                 count_offset = 32;
 402         } else
 403                 return NULL;
 404
 405         if (offset)
 406                 *offset = count_offset;
 407         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
 408 }
 409
 410 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
 411                            int count_offset, int count, struct dx_tail *t)
 412 {
 413         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 414         struct ext4_inode_info *ei = EXT4_I(inode);
 415         __u32 csum;
 416         __le32 save_csum;
 417         int size;
 418
 419         size = count_offset + (count * sizeof(struct dx_entry));
 420         save_csum = t->dt_checksum;
 421         t->dt_checksum = 0;
 422         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 423         csum = ext4_chksum(sbi, csum, (__u8 *)t, sizeof(struct dx_tail));
 424         t->dt_checksum = save_csum;
 425
 426         return cpu_to_le32(csum);
 427 }
 428
 429 static int ext4_dx_csum_verify(struct inode *inode,
 430                                struct ext4_dir_entry *dirent)
 431 {
 432         struct dx_countlimit *c;
 433         struct dx_tail *t;
 434         int count_offset, limit, count;
 435
 436         if (!ext4_has_metadata_csum(inode->i_sb))
 437                 return 1;
 438
 439         c = get_dx_countlimit(inode, dirent, &count_offset);
 440         if (!c) {
 441                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 442                 return 1;
 443         }
 444         limit = le16_to_cpu(c->limit);
 445         count = le16_to_cpu(c->count);
 446         if (count_offset + (limit * sizeof(struct dx_entry)) >
 447             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 448                 warn_no_space_for_csum(inode);
 449                 return 1;
 450         }
 451         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 452
 453         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
 454                                             count, t))
 455                 return 0;
 456         return 1;
 457 }
 458
 459 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
 460 {
 461         struct dx_countlimit *c;
 462         struct dx_tail *t;
 463         int count_offset, limit, count;
 464
 465         if (!ext4_has_metadata_csum(inode->i_sb))
 466                 return;
 467
 468         c = get_dx_countlimit(inode, dirent, &count_offset);
 469         if (!c) {
 470                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 471                 return;
 472         }
 473         limit = le16_to_cpu(c->limit);
 474         count = le16_to_cpu(c->count);
 475         if (count_offset + (limit * sizeof(struct dx_entry)) >
 476             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 477                 warn_no_space_for_csum(inode);
 478                 return;
 479         }
 480         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 481
 482         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
 483 }
 484
 485 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
 486                                             struct inode *inode,
 487                                             struct buffer_head *bh)
 488 {
 489         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 490         return ext4_handle_dirty_metadata(handle, inode, bh);
 491 }
 492
 493 /*
 494  * p is at least 6 bytes before the end of page
 495  */
 496 static inline struct ext4_dir_entry_2 *
 497 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
 498 {
 499         return (struct ext4_dir_entry_2 *)((char *)p +
 500                 ext4_rec_len_from_disk(p->rec_len, blocksize));
 501 }
 502
 503 /*
 504  * Future: use high four bits of block for coalesce-on-delete flags
 505  * Mask them off for now.
 506  */
 507
 508 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
 509 {
 510         return le32_to_cpu(entry->block) & 0x00ffffff;
 511 }
 512
 513 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
 514 {
 515         entry->block = cpu_to_le32(value);
 516 }
 517
 518 static inline unsigned dx_get_hash(struct dx_entry *entry)
 519 {
 520         return le32_to_cpu(entry->hash);
 521 }
 522
 523 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
 524 {
 525         entry->hash = cpu_to_le32(value);
 526 }
 527
 528 static inline unsigned dx_get_count(struct dx_entry *entries)
 529 {
 530         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
 531 }
 532
 533 static inline unsigned dx_get_limit(struct dx_entry *entries)
 534 {
 535         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
 536 }
 537
 538 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
 539 {
 540         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
 541 }
 542
 543 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
 544 {
 545         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
 546 }
 547
 548 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
 549 {
 550         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
 551                 EXT4_DIR_REC_LEN(2) - infosize;
 552
 553         if (ext4_has_metadata_csum(dir->i_sb))
 554                 entry_space -= sizeof(struct dx_tail);
 555         return entry_space / sizeof(struct dx_entry);
 556 }
 557
 558 static inline unsigned dx_node_limit(struct inode *dir)
 559 {
 560         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
 561
 562         if (ext4_has_metadata_csum(dir->i_sb))
 563                 entry_space -= sizeof(struct dx_tail);
 564         return entry_space / sizeof(struct dx_entry);
 565 }
 566
 567 /*
 568  * Debug
 569  */
 570 #ifdef DX_DEBUG
 571 static void dx_show_index(char * label, struct dx_entry *entries)
 572 {
 573         int i, n = dx_get_count (entries);
 574         printk(KERN_DEBUG "%s index ", label);
 575         for (i = 0; i < n; i++) {
 576                 printk("%x->%lu ", i ? dx_get_hash(entries + i) :
 577                                 0, (unsigned long)dx_get_block(entries + i));
 578         }
 579         printk("\n");
 580 }
 581
 582 struct stats
 583 {
 584         unsigned names;
 585         unsigned space;
 586         unsigned bcount;
 587 };
 588
 589 static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext4_dir_entry_2 *de,
 590                                  int size, int show_names)
 591 {
 592         unsigned names = 0, space = 0;
 593         char *base = (char *) de;
 594         struct dx_hash_info h = *hinfo;
 595
 596         printk("names: ");
 597         while ((char *) de < base + size)
 598         {
 599                 if (de->inode)
 600                 {
 601                         if (show_names)
 602                         {
 603                                 int len = de->name_len;
 604                                 char *name = de->name;
 605                                 while (len--) printk("%c", *name++);
 606                                 ext4fs_dirhash(de->name, de->name_len, &h);
 607                                 printk(":%x.%u ", h.hash,
 608                                        (unsigned) ((char *) de - base));
 609                         }
 610                         space += EXT4_DIR_REC_LEN(de->name_len);
 611                         names++;
 612                 }
 613                 de = ext4_next_entry(de, size);
 614         }
 615         printk("(%i)\n", names);
 616         return (struct stats) { names, space, 1 };
 617 }
 618
 619 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 620                              struct dx_entry *entries, int levels)
 621 {
 622         unsigned blocksize = dir->i_sb->s_blocksize;
 623         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
 624         unsigned bcount = 0;
 625         struct buffer_head *bh;
 626         int err;
 627         printk("%i indexed blocks...\n", count);
 628         for (i = 0; i < count; i++, entries++)
 629         {
 630                 ext4_lblk_t block = dx_get_block(entries);
 631                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
 632                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
 633                 struct stats stats;
 634                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
 635                 bh = ext4_bread(NULL,dir, block, 0);
 636                 if (!bh || IS_ERR(bh))
 637                         continue;
 638                 stats = levels?
 639                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
 640                    dx_show_leaf(hinfo, (struct ext4_dir_entry_2 *) bh->b_data, blocksize, 0);
 641                 names += stats.names;
 642                 space += stats.space;
 643                 bcount += stats.bcount;
 644                 brelse(bh);
 645         }
 646         if (bcount)
 647                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
 648                        levels ? "" : "   ", names, space/bcount,
 649                        (space/bcount)*100/blocksize);
 650         return (struct stats) { names, space, bcount};
 651 }
 652 #endif /* DX_DEBUG */
 653
 654 /*
 655  * Probe for a directory leaf block to search.
 656  *
 657  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
 658  * error in the directory index, and the caller should fall back to
 659  * searching the directory normally.  The callers of dx_probe **MUST**
 660  * check for this error code, and make sure it never gets reflected
 661  * back to userspace.
 662  */
 663 static struct dx_frame *
 664 dx_probe(const struct qstr *d_name, struct inode *dir,
 665          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
 666 {
 667         unsigned count, indirect;
 668         struct dx_entry *at, *entries, *p, *q, *m;
 669         struct dx_root *root;
 670         struct dx_frame *frame = frame_in;
 671         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
 672         u32 hash;
 673
 674         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
 675         if (IS_ERR(frame->bh))
 676                 return (struct dx_frame *) frame->bh;
 677
 678         root = (struct dx_root *) frame->bh->b_data;
 679         if (root->info.hash_version != DX_HASH_TEA &&
 680             root->info.hash_version != DX_HASH_HALF_MD4 &&
 681             root->info.hash_version != DX_HASH_LEGACY) {
 682                 ext4_warning(dir->i_sb, "Unrecognised inode hash code %d",
 683                              root->info.hash_version);
 684                 goto fail;
 685         }
 686         hinfo->hash_version = root->info.hash_version;
 687         if (hinfo->hash_version <= DX_HASH_TEA)
 688                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 689         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 690         if (d_name)
 691                 ext4fs_dirhash(d_name->name, d_name->len, hinfo);
 692         hash = hinfo->hash;
 693
 694         if (root->info.unused_flags & 1) {
 695                 ext4_warning(dir->i_sb, "Unimplemented inode hash flags: %#06x",
 696                              root->info.unused_flags);
 697                 goto fail;
 698         }
 699
 700         if ((indirect = root->info.indirect_levels) > 1) {
 701                 ext4_warning(dir->i_sb, "Unimplemented inode hash depth: %#06x",
 702                              root->info.indirect_levels);
 703                 goto fail;
 704         }
 705
 706         entries = (struct dx_entry *) (((char *)&root->info) +
 707                                        root->info.info_length);
 708
 709         if (dx_get_limit(entries) != dx_root_limit(dir,
 710                                                    root->info.info_length)) {
 711                 ext4_warning(dir->i_sb, "dx entry: limit != root limit");
 712                 goto fail;
 713         }
 714
 715         dxtrace(printk("Look up %x", hash));
 716         while (1) {
 717                 count = dx_get_count(entries);
 718                 if (!count || count > dx_get_limit(entries)) {
 719                         ext4_warning(dir->i_sb,
 720                                      "dx entry: no count or count > limit");
 721                         goto fail;
 722                 }
 723
 724                 p = entries + 1;
 725                 q = entries + count - 1;
 726                 while (p <= q) {
 727                         m = p + (q - p)/2;
 728                         dxtrace(printk("."));
 729                         if (dx_get_hash(m) > hash)
 730                                 q = m - 1;
 731                         else
 732                                 p = m + 1;
 733                 }
 734
 735                 if (0) { // linear search cross check
 736                         unsigned n = count - 1;
 737                         at = entries;
 738                         while (n--)
 739                         {
 740                                 dxtrace(printk(","));
 741                                 if (dx_get_hash(++at) > hash)
 742                                 {
 743                                         at--;
 744                                         break;
 745                                 }
 746                         }
 747                         assert (at == p - 1);
 748                 }
 749
 750                 at = p - 1;
 751                 dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at)));
 752                 frame->entries = entries;
 753                 frame->at = at;
 754                 if (!indirect--)
 755                         return frame;
 756                 frame++;
 757                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
 758                 if (IS_ERR(frame->bh)) {
 759                         ret_err = (struct dx_frame *) frame->bh;
 760                         frame->bh = NULL;
 761                         goto fail;
 762                 }
 763                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
 764
 765                 if (dx_get_limit(entries) != dx_node_limit (dir)) {
 766                         ext4_warning(dir->i_sb,
 767                                      "dx entry: limit != node limit");
 768                         goto fail;
 769                 }
 770         }
 771 fail:
 772         while (frame >= frame_in) {
 773                 brelse(frame->bh);
 774                 frame--;
 775         }
 776         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
 777                 ext4_warning(dir->i_sb,
 778                              "Corrupt dir inode %lu, running e2fsck is "
 779                              "recommended.", dir->i_ino);
 780         return ret_err;
 781 }
 782
 783 static void dx_release (struct dx_frame *frames)
 784 {
 785         if (frames[0].bh == NULL)
 786                 return;
 787
 788         if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels)
 789                 brelse(frames[1].bh);
 790         brelse(frames[0].bh);
 791 }
 792
 793 /*
 794  * This function increments the frame pointer to search the next leaf
 795  * block, and reads in the necessary intervening nodes if the search
 796  * should be necessary.  Whether or not the search is necessary is
 797  * controlled by the hash parameter.  If the hash value is even, then
 798  * the search is only continued if the next block starts with that
 799  * hash value.  This is used if we are searching for a specific file.
 800  *
 801  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
 802  *
 803  * This function returns 1 if the caller should continue to search,
 804  * or 0 if it should not.  If there is an error reading one of the
 805  * index blocks, it will a negative error code.
 806  *
 807  * If start_hash is non-null, it will be filled in with the starting
 808  * hash of the next page.
 809  */
 810 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 811                                  struct dx_frame *frame,
 812                                  struct dx_frame *frames,
 813                                  __u32 *start_hash)
 814 {
 815         struct dx_frame *p;
 816         struct buffer_head *bh;
 817         int num_frames = 0;
 818         __u32 bhash;
 819
 820         p = frame;
 821         /*
 822          * Find the next leaf page by incrementing the frame pointer.
 823          * If we run out of entries in the interior node, loop around and
 824          * increment pointer in the parent node.  When we break out of
 825          * this loop, num_frames indicates the number of interior
 826          * nodes need to be read.
 827          */
 828         while (1) {
 829                 if (++(p->at) < p->entries + dx_get_count(p->entries))
 830                         break;
 831                 if (p == frames)
 832                         return 0;
 833                 num_frames++;
 834                 p--;
 835         }
 836
 837         /*
 838          * If the hash is 1, then continue only if the next page has a
 839          * continuation hash of any value.  This is used for readdir
 840          * handling.  Otherwise, check to see if the hash matches the
 841          * desired contiuation hash.  If it doesn't, return since
 842          * there's no point to read in the successive index pages.
 843          */
 844         bhash = dx_get_hash(p->at);
 845         if (start_hash)
 846                 *start_hash = bhash;
 847         if ((hash & 1) == 0) {
 848                 if ((bhash & ~1) != hash)
 849                         return 0;
 850         }
 851         /*
 852          * If the hash is HASH_NB_ALWAYS, we always go to the next
 853          * block so no check is necessary
 854          */
 855         while (num_frames--) {
 856                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
 857                 if (IS_ERR(bh))
 858                         return PTR_ERR(bh);
 859                 p++;
 860                 brelse(p->bh);
 861                 p->bh = bh;
 862                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
 863         }
 864         return 1;
 865 }
 866
 867
 868 /*
 869  * This function fills a red-black tree with information from a
 870  * directory block.  It returns the number directory entries loaded
 871  * into the tree.  If there is an error it is returned in err.
 872  */
 873 static int htree_dirblock_to_tree(struct file *dir_file,
 874                                   struct inode *dir, ext4_lblk_t block,
 875                                   struct dx_hash_info *hinfo,
 876                                   __u32 start_hash, __u32 start_minor_hash)
 877 {
 878         struct buffer_head *bh;
 879         struct ext4_dir_entry_2 *de, *top;
 880         int err = 0, count = 0;
 881
 882         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 883                                                         (unsigned long)block));
 884         bh = ext4_read_dirblock(dir, block, DIRENT);
 885         if (IS_ERR(bh))
 886                 return PTR_ERR(bh);
 887
 888         de = (struct ext4_dir_entry_2 *) bh->b_data;
 889         top = (struct ext4_dir_entry_2 *) ((char *) de +
 890                                            dir->i_sb->s_blocksize -
 891                                            EXT4_DIR_REC_LEN(0));
 892         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
 893                 if (ext4_check_dir_entry(dir, NULL, de, bh,
 894                                 bh->b_data, bh->b_size,
 895                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
 896                                          + ((char *)de - bh->b_data))) {
 897                         /* silently ignore the rest of the block */
 898                         break;
 899                 }
 900                 ext4fs_dirhash(de->name, de->name_len, hinfo);
 901                 if ((hinfo->hash < start_hash) ||
 902                     ((hinfo->hash == start_hash) &&
 903                      (hinfo->minor_hash < start_minor_hash)))
 904                         continue;
 905                 if (de->inode == 0)
 906                         continue;
 907                 if ((err = ext4_htree_store_dirent(dir_file,
 908                                    hinfo->hash, hinfo->minor_hash, de)) != 0) {
 909                         brelse(bh);
 910                         return err;
 911                 }
 912                 count++;
 913         }
 914         brelse(bh);
 915         return count;
 916 }
 917
 918
 919 /*
 920  * This function fills a red-black tree with information from a
 921  * directory.  We start scanning the directory in hash order, starting
 922  * at start_hash and start_minor_hash.
 923  *
 924  * This function returns the number of entries inserted into the tree,
 925  * or a negative error code.
 926  */
 927 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
 928                          __u32 start_minor_hash, __u32 *next_hash)
 929 {
 930         struct dx_hash_info hinfo;
 931         struct ext4_dir_entry_2 *de;
 932         struct dx_frame frames[2], *frame;
 933         struct inode *dir;
 934         ext4_lblk_t block;
 935         int count = 0;
 936         int ret, err;
 937         __u32 hashval;
 938
 939         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
 940                        start_hash, start_minor_hash));
 941         dir = file_inode(dir_file);
 942         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
 943                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
 944                 if (hinfo.hash_version <= DX_HASH_TEA)
 945                         hinfo.hash_version +=
 946                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
 947                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 948                 if (ext4_has_inline_data(dir)) {
 949                         int has_inline_data = 1;
 950                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
 951                                                         &hinfo, start_hash,
 952                                                         start_minor_hash,
 953                                                         &has_inline_data);
 954                         if (has_inline_data) {
 955                                 *next_hash = ~0;
 956                                 return count;
 957                         }
 958                 }
 959                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
 960                                                start_hash, start_minor_hash);
 961                 *next_hash = ~0;
 962                 return count;
 963         }
 964         hinfo.hash = start_hash;
 965         hinfo.minor_hash = 0;
 966         frame = dx_probe(NULL, dir, &hinfo, frames);
 967         if (IS_ERR(frame))
 968                 return PTR_ERR(frame);
 969
 970         /* Add '.' and '..' from the htree header */
 971         if (!start_hash && !start_minor_hash) {
 972                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
 973                 if ((err = ext4_htree_store_dirent(dir_file, 0, 0, de)) != 0)
 974                         goto errout;
 975                 count++;
 976         }
 977         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
 978                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
 979                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
 980                 if ((err = ext4_htree_store_dirent(dir_file, 2, 0, de)) != 0)
 981                         goto errout;
 982                 count++;
 983         }
 984
 985         while (1) {
 986                 block = dx_get_block(frame->at);
 987                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
 988                                              start_hash, start_minor_hash);
 989                 if (ret < 0) {
 990                         err = ret;
 991                         goto errout;
 992                 }
 993                 count += ret;
 994                 hashval = ~0;
 995                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
 996                                             frame, frames, &hashval);
 997                 *next_hash = hashval;
 998                 if (ret < 0) {
 999                         err = ret;
1000                         goto errout;
1001                 }
1002                 /*
1003                  * Stop if:  (a) there are no more entries, or
1004                  * (b) we have inserted at least one entry and the
1005                  * next hash value is not a continuation
1006                  */
1007                 if ((ret == 0) ||
1008                     (count && ((hashval & 1) == 0)))
1009                         break;
1010         }
1011         dx_release(frames);
1012         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1013                        "next hash: %x\n", count, *next_hash));
1014         return count;
1015 errout:
1016         dx_release(frames);
1017         return (err);
1018 }
1019
1020 static inline int search_dirblock(struct buffer_head *bh,
1021                                   struct inode *dir,
1022                                   const struct qstr *d_name,
1023                                   unsigned int offset,
1024                                   struct ext4_dir_entry_2 **res_dir)
1025 {
1026         return search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1027                           d_name, offset, res_dir);
1028 }
1029
1030 /*
1031  * Directory block splitting, compacting
1032  */
1033
1034 /*
1035  * Create map of hash values, offsets, and sizes, stored at end of block.
1036  * Returns number of entries mapped.
1037  */
1038 static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
1039                        struct dx_hash_info *hinfo,
1040                        struct dx_map_entry *map_tail)
1041 {
1042         int count = 0;
1043         char *base = (char *) de;
1044         struct dx_hash_info h = *hinfo;
1045
1046         while ((char *) de < base + blocksize) {
1047                 if (de->name_len && de->inode) {
1048                         ext4fs_dirhash(de->name, de->name_len, &h);
1049                         map_tail--;
1050                         map_tail->hash = h.hash;
1051                         map_tail->offs = ((char *) de - base)>>2;
1052                         map_tail->size = le16_to_cpu(de->rec_len);
1053                         count++;
1054                         cond_resched();
1055                 }
1056                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1057                 de = ext4_next_entry(de, blocksize);
1058         }
1059         return count;
1060 }
1061
1062 /* Sort map by hash value */
1063 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1064 {
1065         struct dx_map_entry *p, *q, *top = map + count - 1;
1066         int more;
1067         /* Combsort until bubble sort doesn't suck */
1068         while (count > 2) {
1069                 count = count*10/13;
1070                 if (count - 9 < 2) /* 9, 10 -> 11 */
1071                         count = 11;
1072                 for (p = top, q = p - count; q >= map; p--, q--)
1073                         if (p->hash < q->hash)
1074                                 swap(*p, *q);
1075         }
1076         /* Garden variety bubble sort */
1077         do {
1078                 more = 0;
1079                 q = top;
1080                 while (q-- > map) {
1081                         if (q[1].hash >= q[0].hash)
1082                                 continue;
1083                         swap(*(q+1), *q);
1084                         more = 1;
1085                 }
1086         } while(more);
1087 }
1088
1089 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1090 {
1091         struct dx_entry *entries = frame->entries;
1092         struct dx_entry *old = frame->at, *new = old + 1;
1093         int count = dx_get_count(entries);
1094
1095         assert(count < dx_get_limit(entries));
1096         assert(old < entries + count);
1097         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1098         dx_set_hash(new, hash);
1099         dx_set_block(new, block);
1100         dx_set_count(entries, count + 1);
1101 }
1102
1103 /*
1104  * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.
1105  *
1106  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
1107  * `de != NULL' is guaranteed by caller.
1108  */
1109 static inline int ext4_match (int len, const char * const name,
1110                               struct ext4_dir_entry_2 * de)
1111 {
1112         if (len != de->name_len)
1113                 return 0;
1114         if (!de->inode)
1115                 return 0;
1116         return !memcmp(name, de->name, len);
1117 }
1118
1119 /*
1120  * Returns 0 if not found, -1 on failure, and 1 on success
1121  */
1122 int search_dir(struct buffer_head *bh,
1123                char *search_buf,
1124                int buf_size,
1125                struct inode *dir,
1126                const struct qstr *d_name,
1127                unsigned int offset,
1128                struct ext4_dir_entry_2 **res_dir)
1129 {
1130         struct ext4_dir_entry_2 * de;
1131         char * dlimit;
1132         int de_len;
1133         const char *name = d_name->name;
1134         int namelen = d_name->len;
1135
1136         de = (struct ext4_dir_entry_2 *)search_buf;
1137         dlimit = search_buf + buf_size;
1138         while ((char *) de < dlimit) {
1139                 /* this code is executed quadratically often */
1140                 /* do minimal checking `by hand' */
1141
1142                 if ((char *) de + namelen <= dlimit &&
1143                     ext4_match (namelen, name, de)) {
1144                         /* found a match - just to be sure, do a full check */
1145                         if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
1146                                                  bh->b_size, offset))
1147                                 return -1;
1148                         *res_dir = de;
1149                         return 1;
1150                 }
1151                 /* prevent looping on a bad block */
1152                 de_len = ext4_rec_len_from_disk(de->rec_len,
1153                                                 dir->i_sb->s_blocksize);
1154                 if (de_len <= 0)
1155                         return -1;
1156                 offset += de_len;
1157                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1158         }
1159         return 0;
1160 }
1161
1162 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1163                                struct ext4_dir_entry *de)
1164 {
1165         struct super_block *sb = dir->i_sb;
1166
1167         if (!is_dx(dir))
1168                 return 0;
1169         if (block == 0)
1170                 return 1;
1171         if (de->inode == 0 &&
1172             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1173                         sb->s_blocksize)
1174                 return 1;
1175         return 0;
1176 }
1177
1178 /*
1179  *      ext4_find_entry()
1180  *
1181  * finds an entry in the specified directory with the wanted name. It
1182  * returns the cache buffer in which the entry was found, and the entry
1183  * itself (as a parameter - res_dir). It does NOT read the inode of the
1184  * entry - you'll have to do that yourself if you want to.
1185  *
1186  * The returned buffer_head has ->b_count elevated.  The caller is expected
1187  * to brelse() it when appropriate.
1188  */
1189 static struct buffer_head * ext4_find_entry (struct inode *dir,
1190                                         const struct qstr *d_name,
1191                                         struct ext4_dir_entry_2 **res_dir,
1192                                         int *inlined)
1193 {
1194         struct super_block *sb;
1195         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1196         struct buffer_head *bh, *ret = NULL;
1197         ext4_lblk_t start, block, b;
1198         const u8 *name = d_name->name;
1199         int ra_max = 0;         /* Number of bh's in the readahead
1200                                    buffer, bh_use[] */
1201         int ra_ptr = 0;         /* Current index into readahead
1202                                    buffer */
1203         int num = 0;
1204         ext4_lblk_t  nblocks;
1205         int i, namelen;
1206
1207         *res_dir = NULL;
1208         sb = dir->i_sb;
1209         namelen = d_name->len;
1210         if (namelen > EXT4_NAME_LEN)
1211                 return NULL;
1212
1213         if (ext4_has_inline_data(dir)) {
1214                 int has_inline_data = 1;
1215                 ret = ext4_find_inline_entry(dir, d_name, res_dir,
1216                                              &has_inline_data);
1217                 if (has_inline_data) {
1218                         if (inlined)
1219                                 *inlined = 1;
1220                         return ret;
1221                 }
1222         }
1223
1224         if ((namelen <= 2) && (name[0] == '.') &&
1225             (name[1] == '.' || name[1] == '\0')) {
1226                 /*
1227                  * "." or ".." will only be in the first block
1228                  * NFS may look up ".."; "." should be handled by the VFS
1229                  */
1230                 block = start = 0;
1231                 nblocks = 1;
1232                 goto restart;
1233         }
1234         if (is_dx(dir)) {
1235                 bh = ext4_dx_find_entry(dir, d_name, res_dir);
1236                 /*
1237                  * On success, or if the error was file not found,
1238                  * return.  Otherwise, fall back to doing a search the
1239                  * old fashioned way.
1240                  */
1241                 if (!IS_ERR(bh) || PTR_ERR(bh) != ERR_BAD_DX_DIR)
1242                         return bh;
1243                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1244                                "falling back\n"));
1245         }
1246         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1247         start = EXT4_I(dir)->i_dir_start_lookup;
1248         if (start >= nblocks)
1249                 start = 0;
1250         block = start;
1251 restart:
1252         do {
1253                 /*
1254                  * We deal with the read-ahead logic here.
1255                  */
1256                 if (ra_ptr >= ra_max) {
1257                         /* Refill the readahead buffer */
1258                         ra_ptr = 0;
1259                         b = block;
1260                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
1261                                 /*
1262                                  * Terminate if we reach the end of the
1263                                  * directory and must wrap, or if our
1264                                  * search has finished at this block.
1265                                  */
1266                                 if (b >= nblocks || (num && block == start)) {
1267                                         bh_use[ra_max] = NULL;
1268                                         break;
1269                                 }
1270                                 num++;
1271                                 bh = ext4_getblk(NULL, dir, b++, 0);
1272                                 if (unlikely(IS_ERR(bh))) {
1273                                         if (ra_max == 0)
1274                                                 return bh;
1275                                         break;
1276                                 }
1277                                 bh_use[ra_max] = bh;
1278                                 if (bh)
1279                                         ll_rw_block(READ | REQ_META | REQ_PRIO,
1280                                                     1, &bh);
1281                         }
1282                 }
1283                 if ((bh = bh_use[ra_ptr++]) == NULL)
1284                         goto next;
1285                 wait_on_buffer(bh);
1286                 if (!buffer_uptodate(bh)) {
1287                         /* read error, skip block & hope for the best */
1288                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1289                                          (unsigned long) block);
1290                         brelse(bh);
1291                         goto next;
1292                 }
1293                 if (!buffer_verified(bh) &&
1294                     !is_dx_internal_node(dir, block,
1295                                          (struct ext4_dir_entry *)bh->b_data) &&
1296                     !ext4_dirent_csum_verify(dir,
1297                                 (struct ext4_dir_entry *)bh->b_data)) {
1298                         EXT4_ERROR_INODE(dir, "checksumming directory "
1299                                          "block %lu", (unsigned long)block);
1300                         brelse(bh);
1301                         goto next;
1302                 }
1303                 set_buffer_verified(bh);
1304                 i = search_dirblock(bh, dir, d_name,
1305                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1306                 if (i == 1) {
1307                         EXT4_I(dir)->i_dir_start_lookup = block;
1308                         ret = bh;
1309                         goto cleanup_and_exit;
1310                 } else {
1311                         brelse(bh);
1312                         if (i < 0)
1313                                 goto cleanup_and_exit;
1314                 }
1315         next:
1316                 if (++block >= nblocks)
1317                         block = 0;
1318         } while (block != start);
1319
1320         /*
1321          * If the directory has grown while we were searching, then
1322          * search the last part of the directory before giving up.
1323          */
1324         block = nblocks;
1325         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1326         if (block < nblocks) {
1327                 start = 0;
1328                 goto restart;
1329         }
1330
1331 cleanup_and_exit:
1332         /* Clean up the read-ahead blocks */
1333         for (; ra_ptr < ra_max; ra_ptr++)
1334                 brelse(bh_use[ra_ptr]);
1335         return ret;
1336 }
1337
1338 static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct qstr *d_name,
1339                        struct ext4_dir_entry_2 **res_dir)
1340 {
1341         struct super_block * sb = dir->i_sb;
1342         struct dx_hash_info     hinfo;
1343         struct dx_frame frames[2], *frame;
1344         struct buffer_head *bh;
1345         ext4_lblk_t block;
1346         int retval;
1347
1348         frame = dx_probe(d_name, dir, &hinfo, frames);
1349         if (IS_ERR(frame))
1350                 return (struct buffer_head *) frame;
1351         do {
1352                 block = dx_get_block(frame->at);
1353                 bh = ext4_read_dirblock(dir, block, DIRENT);
1354                 if (IS_ERR(bh))
1355                         goto errout;
1356
1357                 retval = search_dirblock(bh, dir, d_name,
1358                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1359                                          res_dir);
1360                 if (retval == 1)
1361                         goto success;
1362                 brelse(bh);
1363                 if (retval == -1) {
1364                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1365                         goto errout;
1366                 }
1367
1368                 /* Check to see if we should continue to search */
1369                 retval = ext4_htree_next_block(dir, hinfo.hash, frame,
1370                                                frames, NULL);
1371                 if (retval < 0) {
1372                         ext4_warning(sb,
1373                              "error %d reading index page in directory #%lu",
1374                              retval, dir->i_ino);
1375                         bh = ERR_PTR(retval);
1376                         goto errout;
1377                 }
1378         } while (retval == 1);
1379
1380         bh = NULL;
1381 errout:
1382         dxtrace(printk(KERN_DEBUG "%s not found\n", d_name->name));
1383 success:
1384         dx_release(frames);
1385         return bh;
1386 }
1387
1388 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1389 {
1390         struct inode *inode;
1391         struct ext4_dir_entry_2 *de;
1392         struct buffer_head *bh;
1393
1394         if (dentry->d_name.len > EXT4_NAME_LEN)
1395                 return ERR_PTR(-ENAMETOOLONG);
1396
1397         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1398         if (IS_ERR(bh))
1399                 return (struct dentry *) bh;
1400         inode = NULL;
1401         if (bh) {
1402                 __u32 ino = le32_to_cpu(de->inode);
1403                 brelse(bh);
1404                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1405                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1406                         return ERR_PTR(-EIO);
1407                 }
1408                 if (unlikely(ino == dir->i_ino)) {
1409                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1410                                          dentry);
1411                         return ERR_PTR(-EIO);
1412                 }
1413                 inode = ext4_iget_normal(dir->i_sb, ino);
1414                 if (inode == ERR_PTR(-ESTALE)) {
1415                         EXT4_ERROR_INODE(dir,
1416                                          "deleted inode referenced: %u",
1417                                          ino);
1418                         return ERR_PTR(-EIO);
1419                 }
1420         }
1421         return d_splice_alias(inode, dentry);
1422 }
1423
1424
1425 struct dentry *ext4_get_parent(struct dentry *child)
1426 {
1427         __u32 ino;
1428         static const struct qstr dotdot = QSTR_INIT("..", 2);
1429         struct ext4_dir_entry_2 * de;
1430         struct buffer_head *bh;
1431
1432         bh = ext4_find_entry(child->d_inode, &dotdot, &de, NULL);
1433         if (IS_ERR(bh))
1434                 return (struct dentry *) bh;
1435         if (!bh)
1436                 return ERR_PTR(-ENOENT);
1437         ino = le32_to_cpu(de->inode);
1438         brelse(bh);
1439
1440         if (!ext4_valid_inum(child->d_inode->i_sb, ino)) {
1441                 EXT4_ERROR_INODE(child->d_inode,
1442                                  "bad parent inode number: %u", ino);
1443                 return ERR_PTR(-EIO);
1444         }
1445
1446         return d_obtain_alias(ext4_iget_normal(child->d_inode->i_sb, ino));
1447 }
1448
1449 /*
1450  * Move count entries from end of map between two memory locations.
1451  * Returns pointer to last entry moved.
1452  */
1453 static struct ext4_dir_entry_2 *
1454 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1455                 unsigned blocksize)
1456 {
1457         unsigned rec_len = 0;
1458
1459         while (count--) {
1460                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1461                                                 (from + (map->offs<<2));
1462                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1463                 memcpy (to, de, rec_len);
1464                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1465                                 ext4_rec_len_to_disk(rec_len, blocksize);
1466                 de->inode = 0;
1467                 map++;
1468                 to += rec_len;
1469         }
1470         return (struct ext4_dir_entry_2 *) (to - rec_len);
1471 }
1472
1473 /*
1474  * Compact each dir entry in the range to the minimal rec_len.
1475  * Returns pointer to last entry in range.
1476  */
1477 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1478 {
1479         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1480         unsigned rec_len = 0;
1481
1482         prev = to = de;
1483         while ((char*)de < base + blocksize) {
1484                 next = ext4_next_entry(de, blocksize);
1485                 if (de->inode && de->name_len) {
1486                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1487                         if (de > to)
1488                                 memmove(to, de, rec_len);
1489                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1490                         prev = to;
1491                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1492                 }
1493                 de = next;
1494         }
1495         return prev;
1496 }
1497
1498 /*
1499  * Split a full leaf block to make room for a new dir entry.
1500  * Allocate a new block, and move entries so that they are approx. equally full.
1501  * Returns pointer to de in block into which the new entry will be inserted.
1502  */
1503 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1504                         struct buffer_head **bh,struct dx_frame *frame,
1505                         struct dx_hash_info *hinfo)
1506 {
1507         unsigned blocksize = dir->i_sb->s_blocksize;
1508         unsigned count, continued;
1509         struct buffer_head *bh2;
1510         ext4_lblk_t newblock;
1511         u32 hash2;
1512         struct dx_map_entry *map;
1513         char *data1 = (*bh)->b_data, *data2;
1514         unsigned split, move, size;
1515         struct ext4_dir_entry_2 *de = NULL, *de2;
1516         struct ext4_dir_entry_tail *t;
1517         int     csum_size = 0;
1518         int     err = 0, i;
1519
1520         if (ext4_has_metadata_csum(dir->i_sb))
1521                 csum_size = sizeof(struct ext4_dir_entry_tail);
1522
1523         bh2 = ext4_append(handle, dir, &newblock);
1524         if (IS_ERR(bh2)) {
1525                 brelse(*bh);
1526                 *bh = NULL;
1527                 return (struct ext4_dir_entry_2 *) bh2;
1528         }
1529
1530         BUFFER_TRACE(*bh, "get_write_access");
1531         err = ext4_journal_get_write_access(handle, *bh);
1532         if (err)
1533                 goto journal_error;
1534
1535         BUFFER_TRACE(frame->bh, "get_write_access");
1536         err = ext4_journal_get_write_access(handle, frame->bh);
1537         if (err)
1538                 goto journal_error;
1539
1540         data2 = bh2->b_data;
1541
1542         /* create map in the end of data2 block */
1543         map = (struct dx_map_entry *) (data2 + blocksize);
1544         count = dx_make_map((struct ext4_dir_entry_2 *) data1,
1545                              blocksize, hinfo, map);
1546         map -= count;
1547         dx_sort_map(map, count);
1548         /* Split the existing block in the middle, size-wise */
1549         size = 0;
1550         move = 0;
1551         for (i = count-1; i >= 0; i--) {
1552                 /* is more than half of this entry in 2nd half of the block? */
1553                 if (size + map[i].size/2 > blocksize/2)
1554                         break;
1555                 size += map[i].size;
1556                 move++;
1557         }
1558         /* map index at which we will split */
1559         split = count - move;
1560         hash2 = map[split].hash;
1561         continued = hash2 == map[split - 1].hash;
1562         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1563                         (unsigned long)dx_get_block(frame->at),
1564                                         hash2, split, count-split));
1565
1566         /* Fancy dance to stay within two buffers */
1567         de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
1568         de = dx_pack_dirents(data1, blocksize);
1569         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1570                                            (char *) de,
1571                                            blocksize);
1572         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1573                                             (char *) de2,
1574                                             blocksize);
1575         if (csum_size) {
1576                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1577                 initialize_dirent_tail(t, blocksize);
1578
1579                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1580                 initialize_dirent_tail(t, blocksize);
1581         }
1582
1583         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
1584         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
1585
1586         /* Which block gets the new entry? */
1587         if (hinfo->hash >= hash2) {
1588                 swap(*bh, bh2);
1589                 de = de2;
1590         }
1591         dx_insert_block(frame, hash2 + continued, newblock);
1592         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1593         if (err)
1594                 goto journal_error;
1595         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1596         if (err)
1597                 goto journal_error;
1598         brelse(bh2);
1599         dxtrace(dx_show_index("frame", frame->entries));
1600         return de;
1601
1602 journal_error:
1603         brelse(*bh);
1604         brelse(bh2);
1605         *bh = NULL;
1606         ext4_std_error(dir->i_sb, err);
1607         return ERR_PTR(err);
1608 }
1609
1610 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1611                       struct buffer_head *bh,
1612                       void *buf, int buf_size,
1613                       const char *name, int namelen,
1614                       struct ext4_dir_entry_2 **dest_de)
1615 {
1616         struct ext4_dir_entry_2 *de;
1617         unsigned short reclen = EXT4_DIR_REC_LEN(namelen);
1618         int nlen, rlen;
1619         unsigned int offset = 0;
1620         char *top;
1621
1622         de = (struct ext4_dir_entry_2 *)buf;
1623         top = buf + buf_size - reclen;
1624         while ((char *) de <= top) {
1625                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1626                                          buf, buf_size, offset))
1627                         return -EIO;
1628                 if (ext4_match(namelen, name, de))
1629                         return -EEXIST;
1630                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1631                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1632                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1633                         break;
1634                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1635                 offset += rlen;
1636         }
1637         if ((char *) de > top)
1638                 return -ENOSPC;
1639
1640         *dest_de = de;
1641         return 0;
1642 }
1643
1644 void ext4_insert_dentry(struct inode *inode,
1645                         struct ext4_dir_entry_2 *de,
1646                         int buf_size,
1647                         const char *name, int namelen)
1648 {
1649
1650         int nlen, rlen;
1651
1652         nlen = EXT4_DIR_REC_LEN(de->name_len);
1653         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1654         if (de->inode) {
1655                 struct ext4_dir_entry_2 *de1 =
1656                                 (struct ext4_dir_entry_2 *)((char *)de + nlen);
1657                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1658                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1659                 de = de1;
1660         }
1661         de->file_type = EXT4_FT_UNKNOWN;
1662         de->inode = cpu_to_le32(inode->i_ino);
1663         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1664         de->name_len = namelen;
1665         memcpy(de->name, name, namelen);
1666 }
1667 /*
1668  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1669  * it points to a directory entry which is guaranteed to be large
1670  * enough for new directory entry.  If de is NULL, then
1671  * add_dirent_to_buf will attempt search the directory block for
1672  * space.  It will return -ENOSPC if no space is available, and -EIO
1673  * and -EEXIST if directory entry already exists.
1674  */
1675 static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
1676                              struct inode *inode, struct ext4_dir_entry_2 *de,
1677                              struct buffer_head *bh)
1678 {
1679         struct inode    *dir = dentry->d_parent->d_inode;
1680         const char      *name = dentry->d_name.name;
1681         int             namelen = dentry->d_name.len;
1682         unsigned int    blocksize = dir->i_sb->s_blocksize;
1683         int             csum_size = 0;
1684         int             err;
1685
1686         if (ext4_has_metadata_csum(inode->i_sb))
1687                 csum_size = sizeof(struct ext4_dir_entry_tail);
1688
1689         if (!de) {
1690                 err = ext4_find_dest_de(dir, inode,
1691                                         bh, bh->b_data, blocksize - csum_size,
1692                                         name, namelen, &de);
1693                 if (err)
1694                         return err;
1695         }
1696         BUFFER_TRACE(bh, "get_write_access");
1697         err = ext4_journal_get_write_access(handle, bh);
1698         if (err) {
1699                 ext4_std_error(dir->i_sb, err);
1700                 return err;
1701         }
1702
1703         /* By now the buffer is marked for journaling */
1704         ext4_insert_dentry(inode, de, blocksize, name, namelen);
1705
1706         /*
1707          * XXX shouldn't update any times until successful
1708          * completion of syscall, but too many callers depend
1709          * on this.
1710          *
1711          * XXX similarly, too many callers depend on
1712          * ext4_new_inode() setting the times, but error
1713          * recovery deletes the inode, so the worst that can
1714          * happen is that the times are slightly out of date
1715          * and/or different from the directory change time.
1716          */
1717         dir->i_mtime = dir->i_ctime = ext4_current_time(dir);
1718         ext4_update_dx_flag(dir);
1719         dir->i_version++;
1720         ext4_mark_inode_dirty(handle, dir);
1721         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1722         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1723         if (err)
1724                 ext4_std_error(dir->i_sb, err);
1725         return 0;
1726 }
1727
1728 /*
1729  * This converts a one block unindexed directory to a 3 block indexed
1730  * directory, and adds the dentry to the indexed directory.
1731  */
1732 static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1733                             struct inode *inode, struct buffer_head *bh)
1734 {
1735         struct inode    *dir = dentry->d_parent->d_inode;
1736         const char      *name = dentry->d_name.name;
1737         int             namelen = dentry->d_name.len;
1738         struct buffer_head *bh2;
1739         struct dx_root  *root;
1740         struct dx_frame frames[2], *frame;
1741         struct dx_entry *entries;
1742         struct ext4_dir_entry_2 *de, *de2;
1743         struct ext4_dir_entry_tail *t;
1744         char            *data1, *top;
1745         unsigned        len;
1746         int             retval;
1747         unsigned        blocksize;
1748         struct dx_hash_info hinfo;
1749         ext4_lblk_t  block;
1750         struct fake_dirent *fde;
1751         int             csum_size = 0;
1752
1753         if (ext4_has_metadata_csum(inode->i_sb))
1754                 csum_size = sizeof(struct ext4_dir_entry_tail);
1755
1756         blocksize =  dir->i_sb->s_blocksize;
1757         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1758         BUFFER_TRACE(bh, "get_write_access");
1759         retval = ext4_journal_get_write_access(handle, bh);
1760         if (retval) {
1761                 ext4_std_error(dir->i_sb, retval);
1762                 brelse(bh);
1763                 return retval;
1764         }
1765         root = (struct dx_root *) bh->b_data;
1766
1767         /* The 0th block becomes the root, move the dirents out */
1768         fde = &root->dotdot;
1769         de = (struct ext4_dir_entry_2 *)((char *)fde +
1770                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1771         if ((char *) de >= (((char *) root) + blocksize)) {
1772                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1773                 brelse(bh);
1774                 return -EIO;
1775         }
1776         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1777
1778         /* Allocate new block for the 0th block's dirents */
1779         bh2 = ext4_append(handle, dir, &block);
1780         if (IS_ERR(bh2)) {
1781                 brelse(bh);
1782                 return PTR_ERR(bh2);
1783         }
1784         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1785         data1 = bh2->b_data;
1786
1787         memcpy (data1, de, len);
1788         de = (struct ext4_dir_entry_2 *) data1;
1789         top = data1 + len;
1790         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1791                 de = de2;
1792         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1793                                            (char *) de,
1794                                            blocksize);
1795
1796         if (csum_size) {
1797                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1798                 initialize_dirent_tail(t, blocksize);
1799         }
1800
1801         /* Initialize the root; the dot dirents already exist */
1802         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1803         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
1804                                            blocksize);
1805         memset (&root->info, 0, sizeof(root->info));
1806         root->info.info_length = sizeof(root->info);
1807         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1808         entries = root->entries;
1809         dx_set_block(entries, 1);
1810         dx_set_count(entries, 1);
1811         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
1812
1813         /* Initialize as for dx_probe */
1814         hinfo.hash_version = root->info.hash_version;
1815         if (hinfo.hash_version <= DX_HASH_TEA)
1816                 hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
1817         hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1818         ext4fs_dirhash(name, namelen, &hinfo);
1819         memset(frames, 0, sizeof(frames));
1820         frame = frames;
1821         frame->entries = entries;
1822         frame->at = entries;
1823         frame->bh = bh;
1824         bh = bh2;
1825
1826         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1827         if (retval)
1828                 goto out_frames;
1829         retval = ext4_handle_dirty_dirent_node(handle, dir, bh);
1830         if (retval)
1831                 goto out_frames;
1832
1833         de = do_split(handle,dir, &bh, frame, &hinfo);
1834         if (IS_ERR(de)) {
1835                 retval = PTR_ERR(de);
1836                 goto out_frames;
1837         }
1838         dx_release(frames);
1839
1840         retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
1841         brelse(bh);
1842         return retval;
1843 out_frames:
1844         /*
1845          * Even if the block split failed, we have to properly write
1846          * out all the changes we did so far. Otherwise we can end up
1847          * with corrupted filesystem.
1848          */
1849         ext4_mark_inode_dirty(handle, dir);
1850         dx_release(frames);
1851         return retval;
1852 }
1853
1854 /*
1855  *      ext4_add_entry()
1856  *
1857  * adds a file entry to the specified directory, using the same
1858  * semantics as ext4_find_entry(). It returns NULL if it failed.
1859  *
1860  * NOTE!! The inode part of 'de' is left at 0 - which means you
1861  * may not sleep between calling this and putting something into
1862  * the entry, as someone else might have used it while you slept.
1863  */
1864 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
1865                           struct inode *inode)
1866 {
1867         struct inode *dir = dentry->d_parent->d_inode;
1868         struct buffer_head *bh;
1869         struct ext4_dir_entry_2 *de;
1870         struct ext4_dir_entry_tail *t;
1871         struct super_block *sb;
1872         int     retval;
1873         int     dx_fallback=0;
1874         unsigned blocksize;
1875         ext4_lblk_t block, blocks;
1876         int     csum_size = 0;
1877
1878         if (ext4_has_metadata_csum(inode->i_sb))
1879                 csum_size = sizeof(struct ext4_dir_entry_tail);
1880
1881         sb = dir->i_sb;
1882         blocksize = sb->s_blocksize;
1883         if (!dentry->d_name.len)
1884                 return -EINVAL;
1885
1886         if (ext4_has_inline_data(dir)) {
1887                 retval = ext4_try_add_inline_entry(handle, dentry, inode);
1888                 if (retval < 0)
1889                         return retval;
1890                 if (retval == 1) {
1891                         retval = 0;
1892                         return retval;
1893                 }
1894         }
1895
1896         if (is_dx(dir)) {
1897                 retval = ext4_dx_add_entry(handle, dentry, inode);
1898                 if (!retval || (retval != ERR_BAD_DX_DIR))
1899                         return retval;
1900                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
1901                 dx_fallback++;
1902                 ext4_mark_inode_dirty(handle, dir);
1903         }
1904         blocks = dir->i_size >> sb->s_blocksize_bits;
1905         for (block = 0; block < blocks; block++) {
1906                 bh = ext4_read_dirblock(dir, block, DIRENT);
1907                 if (IS_ERR(bh))
1908                         return PTR_ERR(bh);
1909
1910                 retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1911                 if (retval != -ENOSPC) {
1912                         brelse(bh);
1913                         return retval;
1914                 }
1915
1916                 if (blocks == 1 && !dx_fallback &&
1917                     EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX))
1918                         return make_indexed_dir(handle, dentry, inode, bh);
1919                 brelse(bh);
1920         }
1921         bh = ext4_append(handle, dir, &block);
1922         if (IS_ERR(bh))
1923                 return PTR_ERR(bh);
1924         de = (struct ext4_dir_entry_2 *) bh->b_data;
1925         de->inode = 0;
1926         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
1927
1928         if (csum_size) {
1929                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
1930                 initialize_dirent_tail(t, blocksize);
1931         }
1932
1933         retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
1934         brelse(bh);
1935         if (retval == 0)
1936                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
1937         return retval;
1938 }
1939
1940 /*
1941  * Returns 0 for success, or a negative error value
1942  */
1943 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
1944                              struct inode *inode)
1945 {
1946         struct dx_frame frames[2], *frame;
1947         struct dx_entry *entries, *at;
1948         struct dx_hash_info hinfo;
1949         struct buffer_head *bh;
1950         struct inode *dir = dentry->d_parent->d_inode;
1951         struct super_block *sb = dir->i_sb;
1952         struct ext4_dir_entry_2 *de;
1953         int err;
1954
1955         frame = dx_probe(&dentry->d_name, dir, &hinfo, frames);
1956         if (IS_ERR(frame))
1957                 return PTR_ERR(frame);
1958         entries = frame->entries;
1959         at = frame->at;
1960         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
1961         if (IS_ERR(bh)) {
1962                 err = PTR_ERR(bh);
1963                 bh = NULL;
1964                 goto cleanup;
1965         }
1966
1967         BUFFER_TRACE(bh, "get_write_access");
1968         err = ext4_journal_get_write_access(handle, bh);
1969         if (err)
1970                 goto journal_error;
1971
1972         err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1973         if (err != -ENOSPC)
1974                 goto cleanup;
1975
1976         /* Block full, should compress but for now just split */
1977         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
1978                        dx_get_count(entries), dx_get_limit(entries)));
1979         /* Need to split index? */
1980         if (dx_get_count(entries) == dx_get_limit(entries)) {
1981                 ext4_lblk_t newblock;
1982                 unsigned icount = dx_get_count(entries);
1983                 int levels = frame - frames;
1984                 struct dx_entry *entries2;
1985                 struct dx_node *node2;
1986                 struct buffer_head *bh2;
1987
1988                 if (levels && (dx_get_count(frames->entries) ==
1989                                dx_get_limit(frames->entries))) {
1990                         ext4_warning(sb, "Directory index full!");
1991                         err = -ENOSPC;
1992                         goto cleanup;
1993                 }
1994                 bh2 = ext4_append(handle, dir, &newblock);
1995                 if (IS_ERR(bh2)) {
1996                         err = PTR_ERR(bh2);
1997                         goto cleanup;
1998                 }
1999                 node2 = (struct dx_node *)(bh2->b_data);
2000                 entries2 = node2->entries;
2001                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2002                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2003                                                            sb->s_blocksize);
2004                 BUFFER_TRACE(frame->bh, "get_write_access");
2005                 err = ext4_journal_get_write_access(handle, frame->bh);
2006                 if (err)
2007                         goto journal_error;
2008                 if (levels) {
2009                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2010                         unsigned hash2 = dx_get_hash(entries + icount1);
2011                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2012                                        icount1, icount2));
2013
2014                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2015                         err = ext4_journal_get_write_access(handle,
2016                                                              frames[0].bh);
2017                         if (err)
2018                                 goto journal_error;
2019
2020                         memcpy((char *) entries2, (char *) (entries + icount1),
2021                                icount2 * sizeof(struct dx_entry));
2022                         dx_set_count(entries, icount1);
2023                         dx_set_count(entries2, icount2);
2024                         dx_set_limit(entries2, dx_node_limit(dir));
2025
2026                         /* Which index block gets the new entry? */
2027                         if (at - entries >= icount1) {
2028                                 frame->at = at = at - entries - icount1 + entries2;
2029                                 frame->entries = entries = entries2;
2030                                 swap(frame->bh, bh2);
2031                         }
2032                         dx_insert_block(frames + 0, hash2, newblock);
2033                         dxtrace(dx_show_index("node", frames[1].entries));
2034                         dxtrace(dx_show_index("node",
2035                                ((struct dx_node *) bh2->b_data)->entries));
2036                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2037                         if (err)
2038                                 goto journal_error;
2039                         brelse (bh2);
2040                 } else {
2041                         dxtrace(printk(KERN_DEBUG
2042                                        "Creating second level index...\n"));
2043                         memcpy((char *) entries2, (char *) entries,
2044                                icount * sizeof(struct dx_entry));
2045                         dx_set_limit(entries2, dx_node_limit(dir));
2046
2047                         /* Set up root */
2048                         dx_set_count(entries, 1);
2049                         dx_set_block(entries + 0, newblock);
2050                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
2051
2052                         /* Add new access path frame */
2053                         frame = frames + 1;
2054                         frame->at = at = at - entries + entries2;
2055                         frame->entries = entries = entries2;
2056                         frame->bh = bh2;
2057                         err = ext4_journal_get_write_access(handle,
2058                                                              frame->bh);
2059                         if (err)
2060                                 goto journal_error;
2061                 }
2062                 err = ext4_handle_dirty_dx_node(handle, dir, frames[0].bh);
2063                 if (err) {
2064                         ext4_std_error(inode->i_sb, err);
2065                         goto cleanup;
2066                 }
2067         }
2068         de = do_split(handle, dir, &bh, frame, &hinfo);
2069         if (IS_ERR(de)) {
2070                 err = PTR_ERR(de);
2071                 goto cleanup;
2072         }
2073         err = add_dirent_to_buf(handle, dentry, inode, de, bh);
2074         goto cleanup;
2075
2076 journal_error:
2077         ext4_std_error(dir->i_sb, err);
2078 cleanup:
2079         brelse(bh);
2080         dx_release(frames);
2081         return err;
2082 }
2083
2084 /*
2085  * ext4_generic_delete_entry deletes a directory entry by merging it
2086  * with the previous entry
2087  */
2088 int ext4_generic_delete_entry(handle_t *handle,
2089                               struct inode *dir,
2090                               struct ext4_dir_entry_2 *de_del,
2091                               struct buffer_head *bh,
2092                               void *entry_buf,
2093                               int buf_size,
2094                               int csum_size)
2095 {
2096         struct ext4_dir_entry_2 *de, *pde;
2097         unsigned int blocksize = dir->i_sb->s_blocksize;
2098         int i;
2099
2100         i = 0;
2101         pde = NULL;
2102         de = (struct ext4_dir_entry_2 *)entry_buf;
2103         while (i < buf_size - csum_size) {
2104                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2105                                          bh->b_data, bh->b_size, i))
2106                         return -EIO;
2107                 if (de == de_del)  {
2108                         if (pde)
2109                                 pde->rec_len = ext4_rec_len_to_disk(
2110                                         ext4_rec_len_from_disk(pde->rec_len,
2111                                                                blocksize) +
2112                                         ext4_rec_len_from_disk(de->rec_len,
2113                                                                blocksize),
2114                                         blocksize);
2115                         else
2116                                 de->inode = 0;
2117                         dir->i_version++;
2118                         return 0;
2119                 }
2120                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2121                 pde = de;
2122                 de = ext4_next_entry(de, blocksize);
2123         }
2124         return -ENOENT;
2125 }
2126
2127 static int ext4_delete_entry(handle_t *handle,
2128                              struct inode *dir,
2129                              struct ext4_dir_entry_2 *de_del,
2130                              struct buffer_head *bh)
2131 {
2132         int err, csum_size = 0;
2133
2134         if (ext4_has_inline_data(dir)) {
2135                 int has_inline_data = 1;
2136                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2137                                                &has_inline_data);
2138                 if (has_inline_data)
2139                         return err;
2140         }
2141
2142         if (ext4_has_metadata_csum(dir->i_sb))
2143                 csum_size = sizeof(struct ext4_dir_entry_tail);
2144
2145         BUFFER_TRACE(bh, "get_write_access");
2146         err = ext4_journal_get_write_access(handle, bh);
2147         if (unlikely(err))
2148                 goto out;
2149
2150         err = ext4_generic_delete_entry(handle, dir, de_del,
2151                                         bh, bh->b_data,
2152                                         dir->i_sb->s_blocksize, csum_size);
2153         if (err)
2154                 goto out;
2155
2156         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2157         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2158         if (unlikely(err))
2159                 goto out;
2160
2161         return 0;
2162 out:
2163         if (err != -ENOENT)
2164                 ext4_std_error(dir->i_sb, err);
2165         return err;
2166 }
2167
2168 /*
2169  * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2,
2170  * since this indicates that nlinks count was previously 1.
2171  */
2172 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2173 {
2174         inc_nlink(inode);
2175         if (is_dx(inode) && inode->i_nlink > 1) {
2176                 /* limit is 16-bit i_links_count */
2177                 if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
2178                         set_nlink(inode, 1);
2179                         EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb,
2180                                               EXT4_FEATURE_RO_COMPAT_DIR_NLINK);
2181                 }
2182         }
2183 }
2184
2185 /*
2186  * If a directory had nlink == 1, then we should let it be 1. This indicates
2187  * directory has >EXT4_LINK_MAX subdirs.
2188  */
2189 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2190 {
2191         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2192                 drop_nlink(inode);
2193 }
2194
2195
2196 static int ext4_add_nondir(handle_t *handle,
2197                 struct dentry *dentry, struct inode *inode)
2198 {
2199         int err = ext4_add_entry(handle, dentry, inode);
2200         if (!err) {
2201                 ext4_mark_inode_dirty(handle, inode);
2202                 unlock_new_inode(inode);
2203                 d_instantiate(dentry, inode);
2204                 return 0;
2205         }
2206         drop_nlink(inode);
2207         unlock_new_inode(inode);
2208         iput(inode);
2209         return err;
2210 }
2211
2212 /*
2213  * By the time this is called, we already have created
2214  * the directory cache entry for the new file, but it
2215  * is so far negative - it has no inode.
2216  *
2217  * If the create succeeds, we fill in the inode information
2218  * with d_instantiate().
2219  */
2220 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2221                        bool excl)
2222 {
2223         handle_t *handle;
2224         struct inode *inode;
2225         int err, credits, retries = 0;
2226
2227         dquot_initialize(dir);
2228
2229         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2230                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2231 retry:
2232         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2233                                             NULL, EXT4_HT_DIR, credits);
2234         handle = ext4_journal_current_handle();
2235         err = PTR_ERR(inode);
2236         if (!IS_ERR(inode)) {
2237                 inode->i_op = &ext4_file_inode_operations;
2238                 inode->i_fop = &ext4_file_operations;
2239                 ext4_set_aops(inode);
2240                 err = ext4_add_nondir(handle, dentry, inode);
2241                 if (!err && IS_DIRSYNC(dir))
2242                         ext4_handle_sync(handle);
2243         }
2244         if (handle)
2245                 ext4_journal_stop(handle);
2246         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2247                 goto retry;
2248         return err;
2249 }
2250
2251 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2252                       umode_t mode, dev_t rdev)
2253 {
2254         handle_t *handle;
2255         struct inode *inode;
2256         int err, credits, retries = 0;
2257
2258         if (!new_valid_dev(rdev))
2259                 return -EINVAL;
2260
2261         dquot_initialize(dir);
2262
2263         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2264                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2265 retry:
2266         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2267                                             NULL, EXT4_HT_DIR, credits);
2268         handle = ext4_journal_current_handle();
2269         err = PTR_ERR(inode);
2270         if (!IS_ERR(inode)) {
2271                 init_special_inode(inode, inode->i_mode, rdev);
2272                 inode->i_op = &ext4_special_inode_operations;
2273                 err = ext4_add_nondir(handle, dentry, inode);
2274                 if (!err && IS_DIRSYNC(dir))
2275                         ext4_handle_sync(handle);
2276         }
2277         if (handle)
2278                 ext4_journal_stop(handle);
2279         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2280                 goto retry;
2281         return err;
2282 }
2283
2284 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2285 {
2286         handle_t *handle;
2287         struct inode *inode;
2288         int err, retries = 0;
2289
2290         dquot_initialize(dir);
2291
2292 retry:
2293         inode = ext4_new_inode_start_handle(dir, mode,
2294                                             NULL, 0, NULL,
2295                                             EXT4_HT_DIR,
2296                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2297                           4 + EXT4_XATTR_TRANS_BLOCKS);
2298         handle = ext4_journal_current_handle();
2299         err = PTR_ERR(inode);
2300         if (!IS_ERR(inode)) {
2301                 inode->i_op = &ext4_file_inode_operations;
2302                 inode->i_fop = &ext4_file_operations;
2303                 ext4_set_aops(inode);
2304                 d_tmpfile(dentry, inode);
2305                 err = ext4_orphan_add(handle, inode);
2306                 if (err)
2307                         goto err_unlock_inode;
2308                 mark_inode_dirty(inode);
2309                 unlock_new_inode(inode);
2310         }
2311         if (handle)
2312                 ext4_journal_stop(handle);
2313         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2314                 goto retry;
2315         return err;
2316 err_unlock_inode:
2317         ext4_journal_stop(handle);
2318         unlock_new_inode(inode);
2319         return err;
2320 }
2321
2322 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2323                           struct ext4_dir_entry_2 *de,
2324                           int blocksize, int csum_size,
2325                           unsigned int parent_ino, int dotdot_real_len)
2326 {
2327         de->inode = cpu_to_le32(inode->i_ino);
2328         de->name_len = 1;
2329         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2330                                            blocksize);
2331         strcpy(de->name, ".");
2332         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2333
2334         de = ext4_next_entry(de, blocksize);
2335         de->inode = cpu_to_le32(parent_ino);
2336         de->name_len = 2;
2337         if (!dotdot_real_len)
2338                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2339                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2340                                         blocksize);
2341         else
2342                 de->rec_len = ext4_rec_len_to_disk(
2343                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2344         strcpy(de->name, "..");
2345         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2346
2347         return ext4_next_entry(de, blocksize);
2348 }
2349
2350 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2351                              struct inode *inode)
2352 {
2353         struct buffer_head *dir_block = NULL;
2354         struct ext4_dir_entry_2 *de;
2355         struct ext4_dir_entry_tail *t;
2356         ext4_lblk_t block = 0;
2357         unsigned int blocksize = dir->i_sb->s_blocksize;
2358         int csum_size = 0;
2359         int err;
2360
2361         if (ext4_has_metadata_csum(dir->i_sb))
2362                 csum_size = sizeof(struct ext4_dir_entry_tail);
2363
2364         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2365                 err = ext4_try_create_inline_dir(handle, dir, inode);
2366                 if (err < 0 && err != -ENOSPC)
2367                         goto out;
2368                 if (!err)
2369                         goto out;
2370         }
2371
2372         inode->i_size = 0;
2373         dir_block = ext4_append(handle, inode, &block);
2374         if (IS_ERR(dir_block))
2375                 return PTR_ERR(dir_block);
2376         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2377         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2378         set_nlink(inode, 2);
2379         if (csum_size) {
2380                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2381                 initialize_dirent_tail(t, blocksize);
2382         }
2383
2384         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2385         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2386         if (err)
2387                 goto out;
2388         set_buffer_verified(dir_block);
2389 out:
2390         brelse(dir_block);
2391         return err;
2392 }
2393
2394 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2395 {
2396         handle_t *handle;
2397         struct inode *inode;
2398         int err, credits, retries = 0;
2399
2400         if (EXT4_DIR_LINK_MAX(dir))
2401                 return -EMLINK;
2402
2403         dquot_initialize(dir);
2404
2405         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2406                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2407 retry:
2408         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2409                                             &dentry->d_name,
2410                                             0, NULL, EXT4_HT_DIR, credits);
2411         handle = ext4_journal_current_handle();
2412         err = PTR_ERR(inode);
2413         if (IS_ERR(inode))
2414                 goto out_stop;
2415
2416         inode->i_op = &ext4_dir_inode_operations;
2417         inode->i_fop = &ext4_dir_operations;
2418         err = ext4_init_new_dir(handle, dir, inode);
2419         if (err)
2420                 goto out_clear_inode;
2421         err = ext4_mark_inode_dirty(handle, inode);
2422         if (!err)
2423                 err = ext4_add_entry(handle, dentry, inode);
2424         if (err) {
2425 out_clear_inode:
2426                 clear_nlink(inode);
2427                 unlock_new_inode(inode);
2428                 ext4_mark_inode_dirty(handle, inode);
2429                 iput(inode);
2430                 goto out_stop;
2431         }
2432         ext4_inc_count(handle, dir);
2433         ext4_update_dx_flag(dir);
2434         err = ext4_mark_inode_dirty(handle, dir);
2435         if (err)
2436                 goto out_clear_inode;
2437         unlock_new_inode(inode);
2438         d_instantiate(dentry, inode);
2439         if (IS_DIRSYNC(dir))
2440                 ext4_handle_sync(handle);
2441
2442 out_stop:
2443         if (handle)
2444                 ext4_journal_stop(handle);
2445         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2446                 goto retry;
2447         return err;
2448 }
2449
2450 /*
2451  * routine to check that the specified directory is empty (for rmdir)
2452  */
2453 static int empty_dir(struct inode *inode)
2454 {
2455         unsigned int offset;
2456         struct buffer_head *bh;
2457         struct ext4_dir_entry_2 *de, *de1;
2458         struct super_block *sb;
2459         int err = 0;
2460
2461         if (ext4_has_inline_data(inode)) {
2462                 int has_inline_data = 1;
2463
2464                 err = empty_inline_dir(inode, &has_inline_data);
2465                 if (has_inline_data)
2466                         return err;
2467         }
2468
2469         sb = inode->i_sb;
2470         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2471                 EXT4_ERROR_INODE(inode, "invalid size");
2472                 return 1;
2473         }
2474         bh = ext4_read_dirblock(inode, 0, EITHER);
2475         if (IS_ERR(bh))
2476                 return 1;
2477
2478         de = (struct ext4_dir_entry_2 *) bh->b_data;
2479         de1 = ext4_next_entry(de, sb->s_blocksize);
2480         if (le32_to_cpu(de->inode) != inode->i_ino ||
2481                         !le32_to_cpu(de1->inode) ||
2482                         strcmp(".", de->name) ||
2483                         strcmp("..", de1->name)) {
2484                 ext4_warning(inode->i_sb,
2485                              "bad directory (dir #%lu) - no `.' or `..'",
2486                              inode->i_ino);
2487                 brelse(bh);
2488                 return 1;
2489         }
2490         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2491                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2492         de = ext4_next_entry(de1, sb->s_blocksize);
2493         while (offset < inode->i_size) {
2494                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2495                         unsigned int lblock;
2496                         err = 0;
2497                         brelse(bh);
2498                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2499                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2500                         if (IS_ERR(bh))
2501                                 return 1;
2502                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2503                 }
2504                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2505                                          bh->b_data, bh->b_size, offset)) {
2506                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2507                                                          sb->s_blocksize);
2508                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2509                         continue;
2510                 }
2511                 if (le32_to_cpu(de->inode)) {
2512                         brelse(bh);
2513                         return 0;
2514                 }
2515                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2516                 de = ext4_next_entry(de, sb->s_blocksize);
2517         }
2518         brelse(bh);
2519         return 1;
2520 }
2521
2522 /*
2523  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2524  * such inodes, starting at the superblock, in case we crash before the
2525  * file is closed/deleted, or in case the inode truncate spans multiple
2526  * transactions and the last transaction is not recovered after a crash.
2527  *
2528  * At filesystem recovery time, we walk this list deleting unlinked
2529  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2530  *
2531  * Orphan list manipulation functions must be called under i_mutex unless
2532  * we are just creating the inode or deleting it.
2533  */
2534 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2535 {
2536         struct super_block *sb = inode->i_sb;
2537         struct ext4_sb_info *sbi = EXT4_SB(sb);
2538         struct ext4_iloc iloc;
2539         int err = 0, rc;
2540         bool dirty = false;
2541
2542         if (!sbi->s_journal || is_bad_inode(inode))
2543                 return 0;
2544
2545         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2546                      !mutex_is_locked(&inode->i_mutex));
2547         /*
2548          * Exit early if inode already is on orphan list. This is a big speedup
2549          * since we don't have to contend on the global s_orphan_lock.
2550          */
2551         if (!list_empty(&EXT4_I(inode)->i_orphan))
2552                 return 0;
2553
2554         /*
2555          * Orphan handling is only valid for files with data blocks
2556          * being truncated, or files being unlinked. Note that we either
2557          * hold i_mutex, or the inode can not be referenced from outside,
2558          * so i_nlink should not be bumped due to race
2559          */
2560         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2561                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2562
2563         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2564         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2565         if (err)
2566                 goto out;
2567
2568         err = ext4_reserve_inode_write(handle, inode, &iloc);
2569         if (err)
2570                 goto out;
2571
2572         mutex_lock(&sbi->s_orphan_lock);
2573         /*
2574          * Due to previous errors inode may be already a part of on-disk
2575          * orphan list. If so skip on-disk list modification.
2576          */
2577         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2578             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2579                 /* Insert this inode at the head of the on-disk orphan list */
2580                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2581                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2582                 dirty = true;
2583         }
2584         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2585         mutex_unlock(&sbi->s_orphan_lock);
2586
2587         if (dirty) {
2588                 err = ext4_handle_dirty_super(handle, sb);
2589                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2590                 if (!err)
2591                         err = rc;
2592                 if (err) {
2593                         /*
2594                          * We have to remove inode from in-memory list if
2595                          * addition to on disk orphan list failed. Stray orphan
2596                          * list entries can cause panics at unmount time.
2597                          */
2598                         mutex_lock(&sbi->s_orphan_lock);
2599                         list_del(&EXT4_I(inode)->i_orphan);
2600                         mutex_unlock(&sbi->s_orphan_lock);
2601                 }
2602         }
2603         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2604         jbd_debug(4, "orphan inode %lu will point to %d\n",
2605                         inode->i_ino, NEXT_ORPHAN(inode));
2606 out:
2607         ext4_std_error(sb, err);
2608         return err;
2609 }
2610
2611 /*
2612  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2613  * of such inodes stored on disk, because it is finally being cleaned up.
2614  */
2615 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2616 {
2617         struct list_head *prev;
2618         struct ext4_inode_info *ei = EXT4_I(inode);
2619         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2620         __u32 ino_next;
2621         struct ext4_iloc iloc;
2622         int err = 0;
2623
2624         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2625                 return 0;
2626
2627         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2628                      !mutex_is_locked(&inode->i_mutex));
2629         /* Do this quick check before taking global s_orphan_lock. */
2630         if (list_empty(&ei->i_orphan))
2631                 return 0;
2632
2633         if (handle) {
2634                 /* Grab inode buffer early before taking global s_orphan_lock */
2635                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2636         }
2637
2638         mutex_lock(&sbi->s_orphan_lock);
2639         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2640
2641         prev = ei->i_orphan.prev;
2642         list_del_init(&ei->i_orphan);
2643
2644         /* If we're on an error path, we may not have a valid
2645          * transaction handle with which to update the orphan list on
2646          * disk, but we still need to remove the inode from the linked
2647          * list in memory. */
2648         if (!handle || err) {
2649                 mutex_unlock(&sbi->s_orphan_lock);
2650                 goto out_err;
2651         }
2652
2653         ino_next = NEXT_ORPHAN(inode);
2654         if (prev == &sbi->s_orphan) {
2655                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2656                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2657                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2658                 if (err) {
2659                         mutex_unlock(&sbi->s_orphan_lock);
2660                         goto out_brelse;
2661                 }
2662                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2663                 mutex_unlock(&sbi->s_orphan_lock);
2664                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2665         } else {
2666                 struct ext4_iloc iloc2;
2667                 struct inode *i_prev =
2668                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2669
2670                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2671                           i_prev->i_ino, ino_next);
2672                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2673                 if (err) {
2674                         mutex_unlock(&sbi->s_orphan_lock);
2675                         goto out_brelse;
2676                 }
2677                 NEXT_ORPHAN(i_prev) = ino_next;
2678                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2679                 mutex_unlock(&sbi->s_orphan_lock);
2680         }
2681         if (err)
2682                 goto out_brelse;
2683         NEXT_ORPHAN(inode) = 0;
2684         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2685 out_err:
2686         ext4_std_error(inode->i_sb, err);
2687         return err;
2688
2689 out_brelse:
2690         brelse(iloc.bh);
2691         goto out_err;
2692 }
2693
2694 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2695 {
2696         int retval;
2697         struct inode *inode;
2698         struct buffer_head *bh;
2699         struct ext4_dir_entry_2 *de;
2700         handle_t *handle = NULL;
2701
2702         /* Initialize quotas before so that eventual writes go in
2703          * separate transaction */
2704         dquot_initialize(dir);
2705         dquot_initialize(dentry->d_inode);
2706
2707         retval = -ENOENT;
2708         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2709         if (IS_ERR(bh))
2710                 return PTR_ERR(bh);
2711         if (!bh)
2712                 goto end_rmdir;
2713
2714         inode = dentry->d_inode;
2715
2716         retval = -EIO;
2717         if (le32_to_cpu(de->inode) != inode->i_ino)
2718                 goto end_rmdir;
2719
2720         retval = -ENOTEMPTY;
2721         if (!empty_dir(inode))
2722                 goto end_rmdir;
2723
2724         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2725                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2726         if (IS_ERR(handle)) {
2727                 retval = PTR_ERR(handle);
2728                 handle = NULL;
2729                 goto end_rmdir;
2730         }
2731
2732         if (IS_DIRSYNC(dir))
2733                 ext4_handle_sync(handle);
2734
2735         retval = ext4_delete_entry(handle, dir, de, bh);
2736         if (retval)
2737                 goto end_rmdir;
2738         if (!EXT4_DIR_LINK_EMPTY(inode))
2739                 ext4_warning(inode->i_sb,
2740                              "empty directory has too many links (%d)",
2741                              inode->i_nlink);
2742         inode->i_version++;
2743         clear_nlink(inode);
2744         /* There's no need to set i_disksize: the fact that i_nlink is
2745          * zero will ensure that the right thing happens during any
2746          * recovery. */
2747         inode->i_size = 0;
2748         ext4_orphan_add(handle, inode);
2749         inode->i_ctime = dir->i_ctime = dir->i_mtime = ext4_current_time(inode);
2750         ext4_mark_inode_dirty(handle, inode);
2751         ext4_dec_count(handle, dir);
2752         ext4_update_dx_flag(dir);
2753         ext4_mark_inode_dirty(handle, dir);
2754
2755 end_rmdir:
2756         brelse(bh);
2757         if (handle)
2758                 ext4_journal_stop(handle);
2759         return retval;
2760 }
2761
2762 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2763 {
2764         int retval;
2765         struct inode *inode;
2766         struct buffer_head *bh;
2767         struct ext4_dir_entry_2 *de;
2768         handle_t *handle = NULL;
2769
2770         trace_ext4_unlink_enter(dir, dentry);
2771         /* Initialize quotas before so that eventual writes go
2772          * in separate transaction */
2773         dquot_initialize(dir);
2774         dquot_initialize(dentry->d_inode);
2775
2776         retval = -ENOENT;
2777         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2778         if (IS_ERR(bh))
2779                 return PTR_ERR(bh);
2780         if (!bh)
2781                 goto end_unlink;
2782
2783         inode = dentry->d_inode;
2784
2785         retval = -EIO;
2786         if (le32_to_cpu(de->inode) != inode->i_ino)
2787                 goto end_unlink;
2788
2789         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2790                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2791         if (IS_ERR(handle)) {
2792                 retval = PTR_ERR(handle);
2793                 handle = NULL;
2794                 goto end_unlink;
2795         }
2796
2797         if (IS_DIRSYNC(dir))
2798                 ext4_handle_sync(handle);
2799
2800         if (!inode->i_nlink) {
2801                 ext4_warning(inode->i_sb,
2802                              "Deleting nonexistent file (%lu), %d",
2803                              inode->i_ino, inode->i_nlink);
2804                 set_nlink(inode, 1);
2805         }
2806         retval = ext4_delete_entry(handle, dir, de, bh);
2807         if (retval)
2808                 goto end_unlink;
2809         dir->i_ctime = dir->i_mtime = ext4_current_time(dir);
2810         ext4_update_dx_flag(dir);
2811         ext4_mark_inode_dirty(handle, dir);
2812         drop_nlink(inode);
2813         if (!inode->i_nlink)
2814                 ext4_orphan_add(handle, inode);
2815         inode->i_ctime = ext4_current_time(inode);
2816         ext4_mark_inode_dirty(handle, inode);
2817         retval = 0;
2818
2819 end_unlink:
2820         brelse(bh);
2821         if (handle)
2822                 ext4_journal_stop(handle);
2823         trace_ext4_unlink_exit(dentry, retval);
2824         return retval;
2825 }
2826
2827 static int ext4_symlink(struct inode *dir,
2828                         struct dentry *dentry, const char *symname)
2829 {
2830         handle_t *handle;
2831         struct inode *inode;
2832         int l, err, retries = 0;
2833         int credits;
2834
2835         l = strlen(symname)+1;
2836         if (l > dir->i_sb->s_blocksize)
2837                 return -ENAMETOOLONG;
2838
2839         dquot_initialize(dir);
2840
2841         if (l > EXT4_N_BLOCKS * 4) {
2842                 /*
2843                  * For non-fast symlinks, we just allocate inode and put it on
2844                  * orphan list in the first transaction => we need bitmap,
2845                  * group descriptor, sb, inode block, quota blocks, and
2846                  * possibly selinux xattr blocks.
2847                  */
2848                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2849                           EXT4_XATTR_TRANS_BLOCKS;
2850         } else {
2851                 /*
2852                  * Fast symlink. We have to add entry to directory
2853                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
2854                  * allocate new inode (bitmap, group descriptor, inode block,
2855                  * quota blocks, sb is already counted in previous macros).
2856                  */
2857                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2858                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
2859         }
2860 retry:
2861         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
2862                                             &dentry->d_name, 0, NULL,
2863                                             EXT4_HT_DIR, credits);
2864         handle = ext4_journal_current_handle();
2865         err = PTR_ERR(inode);
2866         if (IS_ERR(inode))
2867                 goto out_stop;
2868
2869         if (l > EXT4_N_BLOCKS * 4) {
2870                 inode->i_op = &ext4_symlink_inode_operations;
2871                 ext4_set_aops(inode);
2872                 /*
2873                  * We cannot call page_symlink() with transaction started
2874                  * because it calls into ext4_write_begin() which can wait
2875                  * for transaction commit if we are running out of space
2876                  * and thus we deadlock. So we have to stop transaction now
2877                  * and restart it when symlink contents is written.
2878                  *
2879                  * To keep fs consistent in case of crash, we have to put inode
2880                  * to orphan list in the mean time.
2881                  */
2882                 drop_nlink(inode);
2883                 err = ext4_orphan_add(handle, inode);
2884                 ext4_journal_stop(handle);
2885                 if (err)
2886                         goto err_drop_inode;
2887                 err = __page_symlink(inode, symname, l, 1);
2888                 if (err)
2889                         goto err_drop_inode;
2890                 /*
2891                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
2892                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
2893                  */
2894                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
2895                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2896                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
2897                 if (IS_ERR(handle)) {
2898                         err = PTR_ERR(handle);
2899                         goto err_drop_inode;
2900                 }
2901                 set_nlink(inode, 1);
2902                 err = ext4_orphan_del(handle, inode);
2903                 if (err) {
2904                         ext4_journal_stop(handle);
2905                         clear_nlink(inode);
2906                         goto err_drop_inode;
2907                 }
2908         } else {
2909                 /* clear the extent format for fast symlink */
2910                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
2911                 inode->i_op = &ext4_fast_symlink_inode_operations;
2912                 memcpy((char *)&EXT4_I(inode)->i_data, symname, l);
2913                 inode->i_size = l-1;
2914         }
2915         EXT4_I(inode)->i_disksize = inode->i_size;
2916         err = ext4_add_nondir(handle, dentry, inode);
2917         if (!err && IS_DIRSYNC(dir))
2918                 ext4_handle_sync(handle);
2919
2920 out_stop:
2921         if (handle)
2922                 ext4_journal_stop(handle);
2923         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2924                 goto retry;
2925         return err;
2926 err_drop_inode:
2927         unlock_new_inode(inode);
2928         iput(inode);
2929         return err;
2930 }
2931
2932 static int ext4_link(struct dentry *old_dentry,
2933                      struct inode *dir, struct dentry *dentry)
2934 {
2935         handle_t *handle;
2936         struct inode *inode = old_dentry->d_inode;
2937         int err, retries = 0;
2938
2939         if (inode->i_nlink >= EXT4_LINK_MAX)
2940                 return -EMLINK;
2941
2942         dquot_initialize(dir);
2943
2944 retry:
2945         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2946                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2947                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
2948         if (IS_ERR(handle))
2949                 return PTR_ERR(handle);
2950
2951         if (IS_DIRSYNC(dir))
2952                 ext4_handle_sync(handle);
2953
2954         inode->i_ctime = ext4_current_time(inode);
2955         ext4_inc_count(handle, inode);
2956         ihold(inode);
2957
2958         err = ext4_add_entry(handle, dentry, inode);
2959         if (!err) {
2960                 ext4_mark_inode_dirty(handle, inode);
2961                 /* this can happen only for tmpfile being
2962                  * linked the first time
2963                  */
2964                 if (inode->i_nlink == 1)
2965                         ext4_orphan_del(handle, inode);
2966                 d_instantiate(dentry, inode);
2967         } else {
2968                 drop_nlink(inode);
2969                 iput(inode);
2970         }
2971         ext4_journal_stop(handle);
2972         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2973                 goto retry;
2974         return err;
2975 }
2976
2977
2978 /*
2979  * Try to find buffer head where contains the parent block.
2980  * It should be the inode block if it is inlined or the 1st block
2981  * if it is a normal dir.
2982  */
2983 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
2984                                         struct inode *inode,
2985                                         int *retval,
2986                                         struct ext4_dir_entry_2 **parent_de,
2987                                         int *inlined)
2988 {
2989         struct buffer_head *bh;
2990
2991         if (!ext4_has_inline_data(inode)) {
2992                 bh = ext4_read_dirblock(inode, 0, EITHER);
2993                 if (IS_ERR(bh)) {
2994                         *retval = PTR_ERR(bh);
2995                         return NULL;
2996                 }
2997                 *parent_de = ext4_next_entry(
2998                                         (struct ext4_dir_entry_2 *)bh->b_data,
2999                                         inode->i_sb->s_blocksize);
3000                 return bh;
3001         }
3002
3003         *inlined = 1;
3004         return ext4_get_first_inline_block(inode, parent_de, retval);
3005 }
3006
3007 struct ext4_renament {
3008         struct inode *dir;
3009         struct dentry *dentry;
3010         struct inode *inode;
3011         bool is_dir;
3012         int dir_nlink_delta;
3013
3014         /* entry for "dentry" */
3015         struct buffer_head *bh;
3016         struct ext4_dir_entry_2 *de;
3017         int inlined;
3018
3019         /* entry for ".." in inode if it's a directory */
3020         struct buffer_head *dir_bh;
3021         struct ext4_dir_entry_2 *parent_de;
3022         int dir_inlined;
3023 };
3024
3025 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3026 {
3027         int retval;
3028
3029         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3030                                               &retval, &ent->parent_de,
3031                                               &ent->dir_inlined);
3032         if (!ent->dir_bh)
3033                 return retval;
3034         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3035                 return -EIO;
3036         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3037         return ext4_journal_get_write_access(handle, ent->dir_bh);
3038 }
3039
3040 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3041                                   unsigned dir_ino)
3042 {
3043         int retval;
3044
3045         ent->parent_de->inode = cpu_to_le32(dir_ino);
3046         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3047         if (!ent->dir_inlined) {
3048                 if (is_dx(ent->inode)) {
3049                         retval = ext4_handle_dirty_dx_node(handle,
3050                                                            ent->inode,
3051                                                            ent->dir_bh);
3052                 } else {
3053                         retval = ext4_handle_dirty_dirent_node(handle,
3054                                                                ent->inode,
3055                                                                ent->dir_bh);
3056                 }
3057         } else {
3058                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3059         }
3060         if (retval) {
3061                 ext4_std_error(ent->dir->i_sb, retval);
3062                 return retval;
3063         }
3064         return 0;
3065 }
3066
3067 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3068                        unsigned ino, unsigned file_type)
3069 {
3070         int retval;
3071
3072         BUFFER_TRACE(ent->bh, "get write access");
3073         retval = ext4_journal_get_write_access(handle, ent->bh);
3074         if (retval)
3075                 return retval;
3076         ent->de->inode = cpu_to_le32(ino);
3077         if (EXT4_HAS_INCOMPAT_FEATURE(ent->dir->i_sb,
3078                                       EXT4_FEATURE_INCOMPAT_FILETYPE))
3079                 ent->de->file_type = file_type;
3080         ent->dir->i_version++;
3081         ent->dir->i_ctime = ent->dir->i_mtime =
3082                 ext4_current_time(ent->dir);
3083         ext4_mark_inode_dirty(handle, ent->dir);
3084         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3085         if (!ent->inlined) {
3086                 retval = ext4_handle_dirty_dirent_node(handle,
3087                                                        ent->dir, ent->bh);
3088                 if (unlikely(retval)) {
3089                         ext4_std_error(ent->dir->i_sb, retval);
3090                         return retval;
3091                 }
3092         }
3093         brelse(ent->bh);
3094         ent->bh = NULL;
3095
3096         return 0;
3097 }
3098
3099 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3100                                   const struct qstr *d_name)
3101 {
3102         int retval = -ENOENT;
3103         struct buffer_head *bh;
3104         struct ext4_dir_entry_2 *de;
3105
3106         bh = ext4_find_entry(dir, d_name, &de, NULL);
3107         if (IS_ERR(bh))
3108                 return PTR_ERR(bh);
3109         if (bh) {
3110                 retval = ext4_delete_entry(handle, dir, de, bh);
3111                 brelse(bh);
3112         }
3113         return retval;
3114 }
3115
3116 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3117                                int force_reread)
3118 {
3119         int retval;
3120         /*
3121          * ent->de could have moved from under us during htree split, so make
3122          * sure that we are deleting the right entry.  We might also be pointing
3123          * to a stale entry in the unused part of ent->bh so just checking inum
3124          * and the name isn't enough.
3125          */
3126         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3127             ent->de->name_len != ent->dentry->d_name.len ||
3128             strncmp(ent->de->name, ent->dentry->d_name.name,
3129                     ent->de->name_len) ||
3130             force_reread) {
3131                 retval = ext4_find_delete_entry(handle, ent->dir,
3132                                                 &ent->dentry->d_name);
3133         } else {
3134                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3135                 if (retval == -ENOENT) {
3136                         retval = ext4_find_delete_entry(handle, ent->dir,
3137                                                         &ent->dentry->d_name);
3138                 }
3139         }
3140
3141         if (retval) {
3142                 ext4_warning(ent->dir->i_sb,
3143                                 "Deleting old file (%lu), %d, error=%d",
3144                                 ent->dir->i_ino, ent->dir->i_nlink, retval);
3145         }
3146 }
3147
3148 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3149 {
3150         if (ent->dir_nlink_delta) {
3151                 if (ent->dir_nlink_delta == -1)
3152                         ext4_dec_count(handle, ent->dir);
3153                 else
3154                         ext4_inc_count(handle, ent->dir);
3155                 ext4_mark_inode_dirty(handle, ent->dir);
3156         }
3157 }
3158
3159 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3160                                               int credits, handle_t **h)
3161 {
3162         struct inode *wh;
3163         handle_t *handle;
3164         int retries = 0;
3165
3166         /*
3167          * for inode block, sb block, group summaries,
3168          * and inode bitmap
3169          */
3170         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3171                     EXT4_XATTR_TRANS_BLOCKS + 4);
3172 retry:
3173         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3174                                          &ent->dentry->d_name, 0, NULL,
3175                                          EXT4_HT_DIR, credits);
3176
3177         handle = ext4_journal_current_handle();
3178         if (IS_ERR(wh)) {
3179                 if (handle)
3180                         ext4_journal_stop(handle);
3181                 if (PTR_ERR(wh) == -ENOSPC &&
3182                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3183                         goto retry;
3184         } else {
3185                 *h = handle;
3186                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3187                 wh->i_op = &ext4_special_inode_operations;
3188         }
3189         return wh;
3190 }
3191
3192 /*
3193  * Anybody can rename anything with this: the permission checks are left to the
3194  * higher-level routines.
3195  *
3196  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3197  * while new_{dentry,inode) refers to the destination dentry/inode
3198  * This comes from rename(const char *oldpath, const char *newpath)
3199  */
3200 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3201                        struct inode *new_dir, struct dentry *new_dentry,
3202                        unsigned int flags)
3203 {
3204         handle_t *handle = NULL;
3205         struct ext4_renament old = {
3206                 .dir = old_dir,
3207                 .dentry = old_dentry,
3208                 .inode = old_dentry->d_inode,
3209         };
3210         struct ext4_renament new = {
3211                 .dir = new_dir,
3212                 .dentry = new_dentry,
3213                 .inode = new_dentry->d_inode,
3214         };
3215         int force_reread;
3216         int retval;
3217         struct inode *whiteout = NULL;
3218         int credits;
3219         u8 old_file_type;
3220
3221         dquot_initialize(old.dir);
3222         dquot_initialize(new.dir);
3223
3224         /* Initialize quotas before so that eventual writes go
3225          * in separate transaction */
3226         if (new.inode)
3227                 dquot_initialize(new.inode);
3228
3229         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3230         if (IS_ERR(old.bh))
3231                 return PTR_ERR(old.bh);
3232         /*
3233          *  Check for inode number is _not_ due to possible IO errors.
3234          *  We might rmdir the source, keep it as pwd of some process
3235          *  and merrily kill the link to whatever was created under the
3236          *  same name. Goodbye sticky bit ;-<
3237          */
3238         retval = -ENOENT;
3239         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3240                 goto end_rename;
3241
3242         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3243                                  &new.de, &new.inlined);
3244         if (IS_ERR(new.bh)) {
3245                 retval = PTR_ERR(new.bh);
3246                 new.bh = NULL;
3247                 goto end_rename;
3248         }
3249         if (new.bh) {
3250                 if (!new.inode) {
3251                         brelse(new.bh);
3252                         new.bh = NULL;
3253                 }
3254         }
3255         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3256                 ext4_alloc_da_blocks(old.inode);
3257
3258         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3259                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3260         if (!(flags & RENAME_WHITEOUT)) {
3261                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3262                 if (IS_ERR(handle))
3263                         return PTR_ERR(handle);
3264         } else {
3265                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3266                 if (IS_ERR(whiteout))
3267                         return PTR_ERR(whiteout);
3268         }
3269
3270         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3271                 ext4_handle_sync(handle);
3272
3273         if (S_ISDIR(old.inode->i_mode)) {
3274                 if (new.inode) {
3275                         retval = -ENOTEMPTY;
3276                         if (!empty_dir(new.inode))
3277                                 goto end_rename;
3278                 } else {
3279                         retval = -EMLINK;
3280                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3281                                 goto end_rename;
3282                 }
3283                 retval = ext4_rename_dir_prepare(handle, &old);
3284                 if (retval)
3285                         goto end_rename;
3286         }
3287         /*
3288          * If we're renaming a file within an inline_data dir and adding or
3289          * setting the new dirent causes a conversion from inline_data to
3290          * extents/blockmap, we need to force the dirent delete code to
3291          * re-read the directory, or else we end up trying to delete a dirent
3292          * from what is now the extent tree root (or a block map).
3293          */
3294         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3295                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3296
3297         old_file_type = old.de->file_type;
3298         if (whiteout) {
3299                 /*
3300                  * Do this before adding a new entry, so the old entry is sure
3301                  * to be still pointing to the valid old entry.
3302                  */
3303                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3304                                      EXT4_FT_CHRDEV);
3305                 if (retval)
3306                         goto end_rename;
3307                 ext4_mark_inode_dirty(handle, whiteout);
3308         }
3309         if (!new.bh) {
3310                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3311                 if (retval)
3312                         goto end_rename;
3313         } else {
3314                 retval = ext4_setent(handle, &new,
3315                                      old.inode->i_ino, old_file_type);
3316                 if (retval)
3317                         goto end_rename;
3318         }
3319         if (force_reread)
3320                 force_reread = !ext4_test_inode_flag(new.dir,
3321                                                      EXT4_INODE_INLINE_DATA);
3322
3323         /*
3324          * Like most other Unix systems, set the ctime for inodes on a
3325          * rename.
3326          */
3327         old.inode->i_ctime = ext4_current_time(old.inode);
3328         ext4_mark_inode_dirty(handle, old.inode);
3329
3330         if (!whiteout) {
3331                 /*
3332                  * ok, that's it
3333                  */
3334                 ext4_rename_delete(handle, &old, force_reread);
3335         }
3336
3337         if (new.inode) {
3338                 ext4_dec_count(handle, new.inode);
3339                 new.inode->i_ctime = ext4_current_time(new.inode);
3340         }
3341         old.dir->i_ctime = old.dir->i_mtime = ext4_current_time(old.dir);
3342         ext4_update_dx_flag(old.dir);
3343         if (old.dir_bh) {
3344                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3345                 if (retval)
3346                         goto end_rename;
3347
3348                 ext4_dec_count(handle, old.dir);
3349                 if (new.inode) {
3350                         /* checked empty_dir above, can't have another parent,
3351                          * ext4_dec_count() won't work for many-linked dirs */
3352                         clear_nlink(new.inode);
3353                 } else {
3354                         ext4_inc_count(handle, new.dir);
3355                         ext4_update_dx_flag(new.dir);
3356                         ext4_mark_inode_dirty(handle, new.dir);
3357                 }
3358         }
3359         ext4_mark_inode_dirty(handle, old.dir);
3360         if (new.inode) {
3361                 ext4_mark_inode_dirty(handle, new.inode);
3362                 if (!new.inode->i_nlink)
3363                         ext4_orphan_add(handle, new.inode);
3364         }
3365         retval = 0;
3366
3367 end_rename:
3368         brelse(old.dir_bh);
3369         brelse(old.bh);
3370         brelse(new.bh);
3371         if (whiteout) {
3372                 if (retval)
3373                         drop_nlink(whiteout);
3374                 unlock_new_inode(whiteout);
3375                 iput(whiteout);
3376         }
3377         if (handle)
3378                 ext4_journal_stop(handle);
3379         return retval;
3380 }
3381
3382 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3383                              struct inode *new_dir, struct dentry *new_dentry)
3384 {
3385         handle_t *handle = NULL;
3386         struct ext4_renament old = {
3387                 .dir = old_dir,
3388                 .dentry = old_dentry,
3389                 .inode = old_dentry->d_inode,
3390         };
3391         struct ext4_renament new = {
3392                 .dir = new_dir,
3393                 .dentry = new_dentry,
3394                 .inode = new_dentry->d_inode,
3395         };
3396         u8 new_file_type;
3397         int retval;
3398
3399         dquot_initialize(old.dir);
3400         dquot_initialize(new.dir);
3401
3402         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3403                                  &old.de, &old.inlined);
3404         if (IS_ERR(old.bh))
3405                 return PTR_ERR(old.bh);
3406         /*
3407          *  Check for inode number is _not_ due to possible IO errors.
3408          *  We might rmdir the source, keep it as pwd of some process
3409          *  and merrily kill the link to whatever was created under the
3410          *  same name. Goodbye sticky bit ;-<
3411          */
3412         retval = -ENOENT;
3413         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3414                 goto end_rename;
3415
3416         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3417                                  &new.de, &new.inlined);
3418         if (IS_ERR(new.bh)) {
3419                 retval = PTR_ERR(new.bh);
3420                 new.bh = NULL;
3421                 goto end_rename;
3422         }
3423
3424         /* RENAME_EXCHANGE case: old *and* new must both exist */
3425         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3426                 goto end_rename;
3427
3428         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3429                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3430                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3431         if (IS_ERR(handle))
3432                 return PTR_ERR(handle);
3433
3434         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3435                 ext4_handle_sync(handle);
3436
3437         if (S_ISDIR(old.inode->i_mode)) {
3438                 old.is_dir = true;
3439                 retval = ext4_rename_dir_prepare(handle, &old);
3440                 if (retval)
3441                         goto end_rename;
3442         }
3443         if (S_ISDIR(new.inode->i_mode)) {
3444                 new.is_dir = true;
3445                 retval = ext4_rename_dir_prepare(handle, &new);
3446                 if (retval)
3447                         goto end_rename;
3448         }
3449
3450         /*
3451          * Other than the special case of overwriting a directory, parents'
3452          * nlink only needs to be modified if this is a cross directory rename.
3453          */
3454         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3455                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3456                 new.dir_nlink_delta = -old.dir_nlink_delta;
3457                 retval = -EMLINK;
3458                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3459                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3460                         goto end_rename;
3461         }
3462
3463         new_file_type = new.de->file_type;
3464         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3465         if (retval)
3466                 goto end_rename;
3467
3468         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3469         if (retval)
3470                 goto end_rename;
3471
3472         /*
3473          * Like most other Unix systems, set the ctime for inodes on a
3474          * rename.
3475          */
3476         old.inode->i_ctime = ext4_current_time(old.inode);
3477         new.inode->i_ctime = ext4_current_time(new.inode);
3478         ext4_mark_inode_dirty(handle, old.inode);
3479         ext4_mark_inode_dirty(handle, new.inode);
3480
3481         if (old.dir_bh) {
3482                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3483                 if (retval)
3484                         goto end_rename;
3485         }
3486         if (new.dir_bh) {
3487                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3488                 if (retval)
3489                         goto end_rename;
3490         }
3491         ext4_update_dir_count(handle, &old);
3492         ext4_update_dir_count(handle, &new);
3493         retval = 0;
3494
3495 end_rename:
3496         brelse(old.dir_bh);
3497         brelse(new.dir_bh);
3498         brelse(old.bh);
3499         brelse(new.bh);
3500         if (handle)
3501                 ext4_journal_stop(handle);
3502         return retval;
3503 }
3504
3505 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3506                         struct inode *new_dir, struct dentry *new_dentry,
3507                         unsigned int flags)
3508 {
3509         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3510                 return -EINVAL;
3511
3512         if (flags & RENAME_EXCHANGE) {
3513                 return ext4_cross_rename(old_dir, old_dentry,
3514                                          new_dir, new_dentry);
3515         }
3516
3517         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3518 }
3519
3520 /*
3521  * directories can handle most operations...
3522  */
3523 const struct inode_operations ext4_dir_inode_operations = {
3524         .create         = ext4_create,
3525         .lookup         = ext4_lookup,
3526         .link           = ext4_link,
3527         .unlink         = ext4_unlink,
3528         .symlink        = ext4_symlink,
3529         .mkdir          = ext4_mkdir,
3530         .rmdir          = ext4_rmdir,
3531         .mknod          = ext4_mknod,
3532         .tmpfile        = ext4_tmpfile,
3533         .rename2        = ext4_rename2,
3534         .setattr        = ext4_setattr,
3535         .setxattr       = generic_setxattr,
3536         .getxattr       = generic_getxattr,
3537         .listxattr      = ext4_listxattr,
3538         .removexattr    = generic_removexattr,
3539         .get_acl        = ext4_get_acl,
3540         .set_acl        = ext4_set_acl,
3541         .fiemap         = ext4_fiemap,
3542 };
3543
3544 const struct inode_operations ext4_special_inode_operations = {
3545         .setattr        = ext4_setattr,
3546         .setxattr       = generic_setxattr,
3547         .getxattr       = generic_getxattr,
3548         .listxattr      = ext4_listxattr,
3549         .removexattr    = generic_removexattr,
3550         .get_acl        = ext4_get_acl,
3551         .set_acl        = ext4_set_acl,
3552 };