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/ext4_fs.h>
  32 #include <linux/ext4_jbd2.h>
  33 #include <linux/fcntl.h>
  34 #include <linux/stat.h>
  35 #include <linux/string.h>
  36 #include <linux/quotaops.h>
  37 #include <linux/buffer_head.h>
  38 #include <linux/bio.h>
  39
  40 #include "namei.h"
  41 #include "xattr.h"
  42 #include "acl.h"
  43
  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 #define NAMEI_RA_INDEX(c,b)  (((c) * NAMEI_RA_BLOCKS) + (b))
  51
  52 static struct buffer_head *ext4_append(handle_t *handle,
  53                                         struct inode *inode,
  54                                         u32 *block, int *err)
  55 {
  56         struct buffer_head *bh;
  57
  58         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
  59
  60         if ((bh = ext4_bread(handle, inode, *block, 1, err))) {
  61                 inode->i_size += inode->i_sb->s_blocksize;
  62                 EXT4_I(inode)->i_disksize = inode->i_size;
  63                 ext4_journal_get_write_access(handle,bh);
  64         }
  65         return bh;
  66 }
  67
  68 #ifndef assert
  69 #define assert(test) J_ASSERT(test)
  70 #endif
  71
  72 #ifndef swap
  73 #define swap(x, y) do { typeof(x) z = x; x = y; y = z; } while (0)
  74 #endif
  75
  76 #ifdef DX_DEBUG
  77 #define dxtrace(command) command
  78 #else
  79 #define dxtrace(command)
  80 #endif
  81
  82 struct fake_dirent
  83 {
  84         __le32 inode;
  85         __le16 rec_len;
  86         u8 name_len;
  87         u8 file_type;
  88 };
  89
  90 struct dx_countlimit
  91 {
  92         __le16 limit;
  93         __le16 count;
  94 };
  95
  96 struct dx_entry
  97 {
  98         __le32 hash;
  99         __le32 block;
 100 };
 101
 102 /*
 103  * dx_root_info is laid out so that if it should somehow get overlaid by a
 104  * dirent the two low bits of the hash version will be zero.  Therefore, the
 105  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
 106  */
 107
 108 struct dx_root
 109 {
 110         struct fake_dirent dot;
 111         char dot_name[4];
 112         struct fake_dirent dotdot;
 113         char dotdot_name[4];
 114         struct dx_root_info
 115         {
 116                 __le32 reserved_zero;
 117                 u8 hash_version;
 118                 u8 info_length; /* 8 */
 119                 u8 indirect_levels;
 120                 u8 unused_flags;
 121         }
 122         info;
 123         struct dx_entry entries[0];
 124 };
 125
 126 struct dx_node
 127 {
 128         struct fake_dirent fake;
 129         struct dx_entry entries[0];
 130 };
 131
 132
 133 struct dx_frame
 134 {
 135         struct buffer_head *bh;
 136         struct dx_entry *entries;
 137         struct dx_entry *at;
 138 };
 139
 140 struct dx_map_entry
 141 {
 142         u32 hash;
 143         u32 offs;
 144 };
 145
 146 #ifdef CONFIG_EXT4_INDEX
 147 static inline unsigned dx_get_block (struct dx_entry *entry);
 148 static void dx_set_block (struct dx_entry *entry, unsigned value);
 149 static inline unsigned dx_get_hash (struct dx_entry *entry);
 150 static void dx_set_hash (struct dx_entry *entry, unsigned value);
 151 static unsigned dx_get_count (struct dx_entry *entries);
 152 static unsigned dx_get_limit (struct dx_entry *entries);
 153 static void dx_set_count (struct dx_entry *entries, unsigned value);
 154 static void dx_set_limit (struct dx_entry *entries, unsigned value);
 155 static unsigned dx_root_limit (struct inode *dir, unsigned infosize);
 156 static unsigned dx_node_limit (struct inode *dir);
 157 static struct dx_frame *dx_probe(struct dentry *dentry,
 158                                  struct inode *dir,
 159                                  struct dx_hash_info *hinfo,
 160                                  struct dx_frame *frame,
 161                                  int *err);
 162 static void dx_release (struct dx_frame *frames);
 163 static int dx_make_map (struct ext4_dir_entry_2 *de, int size,
 164                         struct dx_hash_info *hinfo, struct dx_map_entry map[]);
 165 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
 166 static struct ext4_dir_entry_2 *dx_move_dirents (char *from, char *to,
 167                 struct dx_map_entry *offsets, int count);
 168 static struct ext4_dir_entry_2* dx_pack_dirents (char *base, int size);
 169 static void dx_insert_block (struct dx_frame *frame, u32 hash, u32 block);
 170 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 171                                  struct dx_frame *frame,
 172                                  struct dx_frame *frames,
 173                                  __u32 *start_hash);
 174 static struct buffer_head * ext4_dx_find_entry(struct dentry *dentry,
 175                        struct ext4_dir_entry_2 **res_dir, int *err);
 176 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
 177                              struct inode *inode);
 178
 179 /*
 180  * Future: use high four bits of block for coalesce-on-delete flags
 181  * Mask them off for now.
 182  */
 183
 184 static inline unsigned dx_get_block (struct dx_entry *entry)
 185 {
 186         return le32_to_cpu(entry->block) & 0x00ffffff;
 187 }
 188
 189 static inline void dx_set_block (struct dx_entry *entry, unsigned value)
 190 {
 191         entry->block = cpu_to_le32(value);
 192 }
 193
 194 static inline unsigned dx_get_hash (struct dx_entry *entry)
 195 {
 196         return le32_to_cpu(entry->hash);
 197 }
 198
 199 static inline void dx_set_hash (struct dx_entry *entry, unsigned value)
 200 {
 201         entry->hash = cpu_to_le32(value);
 202 }
 203
 204 static inline unsigned dx_get_count (struct dx_entry *entries)
 205 {
 206         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
 207 }
 208
 209 static inline unsigned dx_get_limit (struct dx_entry *entries)
 210 {
 211         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
 212 }
 213
 214 static inline void dx_set_count (struct dx_entry *entries, unsigned value)
 215 {
 216         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
 217 }
 218
 219 static inline void dx_set_limit (struct dx_entry *entries, unsigned value)
 220 {
 221         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
 222 }
 223
 224 static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize)
 225 {
 226         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
 227                 EXT4_DIR_REC_LEN(2) - infosize;
 228         return 0? 20: entry_space / sizeof(struct dx_entry);
 229 }
 230
 231 static inline unsigned dx_node_limit (struct inode *dir)
 232 {
 233         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
 234         return 0? 22: entry_space / sizeof(struct dx_entry);
 235 }
 236
 237 /*
 238  * Debug
 239  */
 240 #ifdef DX_DEBUG
 241 static void dx_show_index (char * label, struct dx_entry *entries)
 242 {
 243         int i, n = dx_get_count (entries);
 244         printk("%s index ", label);
 245         for (i = 0; i < n; i++) {
 246                 printk("%x->%u ", i? dx_get_hash(entries + i) :
 247                                 0, dx_get_block(entries + i));
 248         }
 249         printk("\n");
 250 }
 251
 252 struct stats
 253 {
 254         unsigned names;
 255         unsigned space;
 256         unsigned bcount;
 257 };
 258
 259 static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext4_dir_entry_2 *de,
 260                                  int size, int show_names)
 261 {
 262         unsigned names = 0, space = 0;
 263         char *base = (char *) de;
 264         struct dx_hash_info h = *hinfo;
 265
 266         printk("names: ");
 267         while ((char *) de < base + size)
 268         {
 269                 if (de->inode)
 270                 {
 271                         if (show_names)
 272                         {
 273                                 int len = de->name_len;
 274                                 char *name = de->name;
 275                                 while (len--) printk("%c", *name++);
 276                                 ext4fs_dirhash(de->name, de->name_len, &h);
 277                                 printk(":%x.%u ", h.hash,
 278                                        ((char *) de - base));
 279                         }
 280                         space += EXT4_DIR_REC_LEN(de->name_len);
 281                         names++;
 282                 }
 283                 de = (struct ext4_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
 284         }
 285         printk("(%i)\n", names);
 286         return (struct stats) { names, space, 1 };
 287 }
 288
 289 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 290                              struct dx_entry *entries, int levels)
 291 {
 292         unsigned blocksize = dir->i_sb->s_blocksize;
 293         unsigned count = dx_get_count (entries), names = 0, space = 0, i;
 294         unsigned bcount = 0;
 295         struct buffer_head *bh;
 296         int err;
 297         printk("%i indexed blocks...\n", count);
 298         for (i = 0; i < count; i++, entries++)
 299         {
 300                 u32 block = dx_get_block(entries), hash = i? dx_get_hash(entries): 0;
 301                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
 302                 struct stats stats;
 303                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
 304                 if (!(bh = ext4_bread (NULL,dir, block, 0,&err))) continue;
 305                 stats = levels?
 306                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
 307                    dx_show_leaf(hinfo, (struct ext4_dir_entry_2 *) bh->b_data, blocksize, 0);
 308                 names += stats.names;
 309                 space += stats.space;
 310                 bcount += stats.bcount;
 311                 brelse (bh);
 312         }
 313         if (bcount)
 314                 printk("%snames %u, fullness %u (%u%%)\n", levels?"":"   ",
 315                         names, space/bcount,(space/bcount)*100/blocksize);
 316         return (struct stats) { names, space, bcount};
 317 }
 318 #endif /* DX_DEBUG */
 319
 320 /*
 321  * Probe for a directory leaf block to search.
 322  *
 323  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
 324  * error in the directory index, and the caller should fall back to
 325  * searching the directory normally.  The callers of dx_probe **MUST**
 326  * check for this error code, and make sure it never gets reflected
 327  * back to userspace.
 328  */
 329 static struct dx_frame *
 330 dx_probe(struct dentry *dentry, struct inode *dir,
 331          struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err)
 332 {
 333         unsigned count, indirect;
 334         struct dx_entry *at, *entries, *p, *q, *m;
 335         struct dx_root *root;
 336         struct buffer_head *bh;
 337         struct dx_frame *frame = frame_in;
 338         u32 hash;
 339
 340         frame->bh = NULL;
 341         if (dentry)
 342                 dir = dentry->d_parent->d_inode;
 343         if (!(bh = ext4_bread (NULL,dir, 0, 0, err)))
 344                 goto fail;
 345         root = (struct dx_root *) bh->b_data;
 346         if (root->info.hash_version != DX_HASH_TEA &&
 347             root->info.hash_version != DX_HASH_HALF_MD4 &&
 348             root->info.hash_version != DX_HASH_LEGACY) {
 349                 ext4_warning(dir->i_sb, __FUNCTION__,
 350                              "Unrecognised inode hash code %d",
 351                              root->info.hash_version);
 352                 brelse(bh);
 353                 *err = ERR_BAD_DX_DIR;
 354                 goto fail;
 355         }
 356         hinfo->hash_version = root->info.hash_version;
 357         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 358         if (dentry)
 359                 ext4fs_dirhash(dentry->d_name.name, dentry->d_name.len, hinfo);
 360         hash = hinfo->hash;
 361
 362         if (root->info.unused_flags & 1) {
 363                 ext4_warning(dir->i_sb, __FUNCTION__,
 364                              "Unimplemented inode hash flags: %#06x",
 365                              root->info.unused_flags);
 366                 brelse(bh);
 367                 *err = ERR_BAD_DX_DIR;
 368                 goto fail;
 369         }
 370
 371         if ((indirect = root->info.indirect_levels) > 1) {
 372                 ext4_warning(dir->i_sb, __FUNCTION__,
 373                              "Unimplemented inode hash depth: %#06x",
 374                              root->info.indirect_levels);
 375                 brelse(bh);
 376                 *err = ERR_BAD_DX_DIR;
 377                 goto fail;
 378         }
 379
 380         entries = (struct dx_entry *) (((char *)&root->info) +
 381                                        root->info.info_length);
 382         assert(dx_get_limit(entries) == dx_root_limit(dir,
 383                                                       root->info.info_length));
 384         dxtrace (printk("Look up %x", hash));
 385         while (1)
 386         {
 387                 count = dx_get_count(entries);
 388                 assert (count && count <= dx_get_limit(entries));
 389                 p = entries + 1;
 390                 q = entries + count - 1;
 391                 while (p <= q)
 392                 {
 393                         m = p + (q - p)/2;
 394                         dxtrace(printk("."));
 395                         if (dx_get_hash(m) > hash)
 396                                 q = m - 1;
 397                         else
 398                                 p = m + 1;
 399                 }
 400
 401                 if (0) // linear search cross check
 402                 {
 403                         unsigned n = count - 1;
 404                         at = entries;
 405                         while (n--)
 406                         {
 407                                 dxtrace(printk(","));
 408                                 if (dx_get_hash(++at) > hash)
 409                                 {
 410                                         at--;
 411                                         break;
 412                                 }
 413                         }
 414                         assert (at == p - 1);
 415                 }
 416
 417                 at = p - 1;
 418                 dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at)));
 419                 frame->bh = bh;
 420                 frame->entries = entries;
 421                 frame->at = at;
 422                 if (!indirect--) return frame;
 423                 if (!(bh = ext4_bread (NULL,dir, dx_get_block(at), 0, err)))
 424                         goto fail2;
 425                 at = entries = ((struct dx_node *) bh->b_data)->entries;
 426                 assert (dx_get_limit(entries) == dx_node_limit (dir));
 427                 frame++;
 428         }
 429 fail2:
 430         while (frame >= frame_in) {
 431                 brelse(frame->bh);
 432                 frame--;
 433         }
 434 fail:
 435         return NULL;
 436 }
 437
 438 static void dx_release (struct dx_frame *frames)
 439 {
 440         if (frames[0].bh == NULL)
 441                 return;
 442
 443         if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels)
 444                 brelse(frames[1].bh);
 445         brelse(frames[0].bh);
 446 }
 447
 448 /*
 449  * This function increments the frame pointer to search the next leaf
 450  * block, and reads in the necessary intervening nodes if the search
 451  * should be necessary.  Whether or not the search is necessary is
 452  * controlled by the hash parameter.  If the hash value is even, then
 453  * the search is only continued if the next block starts with that
 454  * hash value.  This is used if we are searching for a specific file.
 455  *
 456  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
 457  *
 458  * This function returns 1 if the caller should continue to search,
 459  * or 0 if it should not.  If there is an error reading one of the
 460  * index blocks, it will a negative error code.
 461  *
 462  * If start_hash is non-null, it will be filled in with the starting
 463  * hash of the next page.
 464  */
 465 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 466                                  struct dx_frame *frame,
 467                                  struct dx_frame *frames,
 468                                  __u32 *start_hash)
 469 {
 470         struct dx_frame *p;
 471         struct buffer_head *bh;
 472         int err, num_frames = 0;
 473         __u32 bhash;
 474
 475         p = frame;
 476         /*
 477          * Find the next leaf page by incrementing the frame pointer.
 478          * If we run out of entries in the interior node, loop around and
 479          * increment pointer in the parent node.  When we break out of
 480          * this loop, num_frames indicates the number of interior
 481          * nodes need to be read.
 482          */
 483         while (1) {
 484                 if (++(p->at) < p->entries + dx_get_count(p->entries))
 485                         break;
 486                 if (p == frames)
 487                         return 0;
 488                 num_frames++;
 489                 p--;
 490         }
 491
 492         /*
 493          * If the hash is 1, then continue only if the next page has a
 494          * continuation hash of any value.  This is used for readdir
 495          * handling.  Otherwise, check to see if the hash matches the
 496          * desired contiuation hash.  If it doesn't, return since
 497          * there's no point to read in the successive index pages.
 498          */
 499         bhash = dx_get_hash(p->at);
 500         if (start_hash)
 501                 *start_hash = bhash;
 502         if ((hash & 1) == 0) {
 503                 if ((bhash & ~1) != hash)
 504                         return 0;
 505         }
 506         /*
 507          * If the hash is HASH_NB_ALWAYS, we always go to the next
 508          * block so no check is necessary
 509          */
 510         while (num_frames--) {
 511                 if (!(bh = ext4_bread(NULL, dir, dx_get_block(p->at),
 512                                       0, &err)))
 513                         return err; /* Failure */
 514                 p++;
 515                 brelse (p->bh);
 516                 p->bh = bh;
 517                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
 518         }
 519         return 1;
 520 }
 521
 522
 523 /*
 524  * p is at least 6 bytes before the end of page
 525  */
 526 static inline struct ext4_dir_entry_2 *ext4_next_entry(struct ext4_dir_entry_2 *p)
 527 {
 528         return (struct ext4_dir_entry_2 *)((char*)p + le16_to_cpu(p->rec_len));
 529 }
 530
 531 /*
 532  * This function fills a red-black tree with information from a
 533  * directory block.  It returns the number directory entries loaded
 534  * into the tree.  If there is an error it is returned in err.
 535  */
 536 static int htree_dirblock_to_tree(struct file *dir_file,
 537                                   struct inode *dir, int block,
 538                                   struct dx_hash_info *hinfo,
 539                                   __u32 start_hash, __u32 start_minor_hash)
 540 {
 541         struct buffer_head *bh;
 542         struct ext4_dir_entry_2 *de, *top;
 543         int err, count = 0;
 544
 545         dxtrace(printk("In htree dirblock_to_tree: block %d\n", block));
 546         if (!(bh = ext4_bread (NULL, dir, block, 0, &err)))
 547                 return err;
 548
 549         de = (struct ext4_dir_entry_2 *) bh->b_data;
 550         top = (struct ext4_dir_entry_2 *) ((char *) de +
 551                                            dir->i_sb->s_blocksize -
 552                                            EXT4_DIR_REC_LEN(0));
 553         for (; de < top; de = ext4_next_entry(de)) {
 554                 if (!ext4_check_dir_entry("htree_dirblock_to_tree", dir, de, bh,
 555                                         (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
 556                                                 +((char *)de - bh->b_data))) {
 557                         /* On error, skip the f_pos to the next block. */
 558                         dir_file->f_pos = (dir_file->f_pos |
 559                                         (dir->i_sb->s_blocksize - 1)) + 1;
 560                         brelse (bh);
 561                         return count;
 562                 }
 563                 ext4fs_dirhash(de->name, de->name_len, hinfo);
 564                 if ((hinfo->hash < start_hash) ||
 565                     ((hinfo->hash == start_hash) &&
 566                      (hinfo->minor_hash < start_minor_hash)))
 567                         continue;
 568                 if (de->inode == 0)
 569                         continue;
 570                 if ((err = ext4_htree_store_dirent(dir_file,
 571                                    hinfo->hash, hinfo->minor_hash, de)) != 0) {
 572                         brelse(bh);
 573                         return err;
 574                 }
 575                 count++;
 576         }
 577         brelse(bh);
 578         return count;
 579 }
 580
 581
 582 /*
 583  * This function fills a red-black tree with information from a
 584  * directory.  We start scanning the directory in hash order, starting
 585  * at start_hash and start_minor_hash.
 586  *
 587  * This function returns the number of entries inserted into the tree,
 588  * or a negative error code.
 589  */
 590 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
 591                          __u32 start_minor_hash, __u32 *next_hash)
 592 {
 593         struct dx_hash_info hinfo;
 594         struct ext4_dir_entry_2 *de;
 595         struct dx_frame frames[2], *frame;
 596         struct inode *dir;
 597         int block, err;
 598         int count = 0;
 599         int ret;
 600         __u32 hashval;
 601
 602         dxtrace(printk("In htree_fill_tree, start hash: %x:%x\n", start_hash,
 603                        start_minor_hash));
 604         dir = dir_file->f_path.dentry->d_inode;
 605         if (!(EXT4_I(dir)->i_flags & EXT4_INDEX_FL)) {
 606                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
 607                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 608                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
 609                                                start_hash, start_minor_hash);
 610                 *next_hash = ~0;
 611                 return count;
 612         }
 613         hinfo.hash = start_hash;
 614         hinfo.minor_hash = 0;
 615         frame = dx_probe(NULL, dir_file->f_path.dentry->d_inode, &hinfo, frames, &err);
 616         if (!frame)
 617                 return err;
 618
 619         /* Add '.' and '..' from the htree header */
 620         if (!start_hash && !start_minor_hash) {
 621                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
 622                 if ((err = ext4_htree_store_dirent(dir_file, 0, 0, de)) != 0)
 623                         goto errout;
 624                 count++;
 625         }
 626         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
 627                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
 628                 de = ext4_next_entry(de);
 629                 if ((err = ext4_htree_store_dirent(dir_file, 2, 0, de)) != 0)
 630                         goto errout;
 631                 count++;
 632         }
 633
 634         while (1) {
 635                 block = dx_get_block(frame->at);
 636                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
 637                                              start_hash, start_minor_hash);
 638                 if (ret < 0) {
 639                         err = ret;
 640                         goto errout;
 641                 }
 642                 count += ret;
 643                 hashval = ~0;
 644                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
 645                                             frame, frames, &hashval);
 646                 *next_hash = hashval;
 647                 if (ret < 0) {
 648                         err = ret;
 649                         goto errout;
 650                 }
 651                 /*
 652                  * Stop if:  (a) there are no more entries, or
 653                  * (b) we have inserted at least one entry and the
 654                  * next hash value is not a continuation
 655                  */
 656                 if ((ret == 0) ||
 657                     (count && ((hashval & 1) == 0)))
 658                         break;
 659         }
 660         dx_release(frames);
 661         dxtrace(printk("Fill tree: returned %d entries, next hash: %x\n",
 662                        count, *next_hash));
 663         return count;
 664 errout:
 665         dx_release(frames);
 666         return (err);
 667 }
 668
 669
 670 /*
 671  * Directory block splitting, compacting
 672  */
 673
 674 static int dx_make_map (struct ext4_dir_entry_2 *de, int size,
 675                         struct dx_hash_info *hinfo, struct dx_map_entry *map_tail)
 676 {
 677         int count = 0;
 678         char *base = (char *) de;
 679         struct dx_hash_info h = *hinfo;
 680
 681         while ((char *) de < base + size)
 682         {
 683                 if (de->name_len && de->inode) {
 684                         ext4fs_dirhash(de->name, de->name_len, &h);
 685                         map_tail--;
 686                         map_tail->hash = h.hash;
 687                         map_tail->offs = (u32) ((char *) de - base);
 688                         count++;
 689                         cond_resched();
 690                 }
 691                 /* XXX: do we need to check rec_len == 0 case? -Chris */
 692                 de = (struct ext4_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
 693         }
 694         return count;
 695 }
 696
 697 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
 698 {
 699         struct dx_map_entry *p, *q, *top = map + count - 1;
 700         int more;
 701         /* Combsort until bubble sort doesn't suck */
 702         while (count > 2) {
 703                 count = count*10/13;
 704                 if (count - 9 < 2) /* 9, 10 -> 11 */
 705                         count = 11;
 706                 for (p = top, q = p - count; q >= map; p--, q--)
 707                         if (p->hash < q->hash)
 708                                 swap(*p, *q);
 709         }
 710         /* Garden variety bubble sort */
 711         do {
 712                 more = 0;
 713                 q = top;
 714                 while (q-- > map) {
 715                         if (q[1].hash >= q[0].hash)
 716                                 continue;
 717                         swap(*(q+1), *q);
 718                         more = 1;
 719                 }
 720         } while(more);
 721 }
 722
 723 static void dx_insert_block(struct dx_frame *frame, u32 hash, u32 block)
 724 {
 725         struct dx_entry *entries = frame->entries;
 726         struct dx_entry *old = frame->at, *new = old + 1;
 727         int count = dx_get_count(entries);
 728
 729         assert(count < dx_get_limit(entries));
 730         assert(old < entries + count);
 731         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
 732         dx_set_hash(new, hash);
 733         dx_set_block(new, block);
 734         dx_set_count(entries, count + 1);
 735 }
 736 #endif
 737
 738
 739 static void ext4_update_dx_flag(struct inode *inode)
 740 {
 741         if (!EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
 742                                      EXT4_FEATURE_COMPAT_DIR_INDEX))
 743                 EXT4_I(inode)->i_flags &= ~EXT4_INDEX_FL;
 744 }
 745
 746 /*
 747  * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.
 748  *
 749  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
 750  * `de != NULL' is guaranteed by caller.
 751  */
 752 static inline int ext4_match (int len, const char * const name,
 753                               struct ext4_dir_entry_2 * de)
 754 {
 755         if (len != de->name_len)
 756                 return 0;
 757         if (!de->inode)
 758                 return 0;
 759         return !memcmp(name, de->name, len);
 760 }
 761
 762 /*
 763  * Returns 0 if not found, -1 on failure, and 1 on success
 764  */
 765 static inline int search_dirblock(struct buffer_head * bh,
 766                                   struct inode *dir,
 767                                   struct dentry *dentry,
 768                                   unsigned long offset,
 769                                   struct ext4_dir_entry_2 ** res_dir)
 770 {
 771         struct ext4_dir_entry_2 * de;
 772         char * dlimit;
 773         int de_len;
 774         const char *name = dentry->d_name.name;
 775         int namelen = dentry->d_name.len;
 776
 777         de = (struct ext4_dir_entry_2 *) bh->b_data;
 778         dlimit = bh->b_data + dir->i_sb->s_blocksize;
 779         while ((char *) de < dlimit) {
 780                 /* this code is executed quadratically often */
 781                 /* do minimal checking `by hand' */
 782
 783                 if ((char *) de + namelen <= dlimit &&
 784                     ext4_match (namelen, name, de)) {
 785                         /* found a match - just to be sure, do a full check */
 786                         if (!ext4_check_dir_entry("ext4_find_entry",
 787                                                   dir, de, bh, offset))
 788                                 return -1;
 789                         *res_dir = de;
 790                         return 1;
 791                 }
 792                 /* prevent looping on a bad block */
 793                 de_len = le16_to_cpu(de->rec_len);
 794                 if (de_len <= 0)
 795                         return -1;
 796                 offset += de_len;
 797                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
 798         }
 799         return 0;
 800 }
 801
 802
 803 /*
 804  *      ext4_find_entry()
 805  *
 806  * finds an entry in the specified directory with the wanted name. It
 807  * returns the cache buffer in which the entry was found, and the entry
 808  * itself (as a parameter - res_dir). It does NOT read the inode of the
 809  * entry - you'll have to do that yourself if you want to.
 810  *
 811  * The returned buffer_head has ->b_count elevated.  The caller is expected
 812  * to brelse() it when appropriate.
 813  */
 814 static struct buffer_head * ext4_find_entry (struct dentry *dentry,
 815                                         struct ext4_dir_entry_2 ** res_dir)
 816 {
 817         struct super_block * sb;
 818         struct buffer_head * bh_use[NAMEI_RA_SIZE];
 819         struct buffer_head * bh, *ret = NULL;
 820         unsigned long start, block, b;
 821         int ra_max = 0;         /* Number of bh's in the readahead
 822                                    buffer, bh_use[] */
 823         int ra_ptr = 0;         /* Current index into readahead
 824                                    buffer */
 825         int num = 0;
 826         int nblocks, i, err;
 827         struct inode *dir = dentry->d_parent->d_inode;
 828         int namelen;
 829         const u8 *name;
 830         unsigned blocksize;
 831
 832         *res_dir = NULL;
 833         sb = dir->i_sb;
 834         blocksize = sb->s_blocksize;
 835         namelen = dentry->d_name.len;
 836         name = dentry->d_name.name;
 837         if (namelen > EXT4_NAME_LEN)
 838                 return NULL;
 839 #ifdef CONFIG_EXT4_INDEX
 840         if (is_dx(dir)) {
 841                 bh = ext4_dx_find_entry(dentry, res_dir, &err);
 842                 /*
 843                  * On success, or if the error was file not found,
 844                  * return.  Otherwise, fall back to doing a search the
 845                  * old fashioned way.
 846                  */
 847                 if (bh || (err != ERR_BAD_DX_DIR))
 848                         return bh;
 849                 dxtrace(printk("ext4_find_entry: dx failed, falling back\n"));
 850         }
 851 #endif
 852         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
 853         start = EXT4_I(dir)->i_dir_start_lookup;
 854         if (start >= nblocks)
 855                 start = 0;
 856         block = start;
 857 restart:
 858         do {
 859                 /*
 860                  * We deal with the read-ahead logic here.
 861                  */
 862                 if (ra_ptr >= ra_max) {
 863                         /* Refill the readahead buffer */
 864                         ra_ptr = 0;
 865                         b = block;
 866                         for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
 867                                 /*
 868                                  * Terminate if we reach the end of the
 869                                  * directory and must wrap, or if our
 870                                  * search has finished at this block.
 871                                  */
 872                                 if (b >= nblocks || (num && block == start)) {
 873                                         bh_use[ra_max] = NULL;
 874                                         break;
 875                                 }
 876                                 num++;
 877                                 bh = ext4_getblk(NULL, dir, b++, 0, &err);
 878                                 bh_use[ra_max] = bh;
 879                                 if (bh)
 880                                         ll_rw_block(READ_META, 1, &bh);
 881                         }
 882                 }
 883                 if ((bh = bh_use[ra_ptr++]) == NULL)
 884                         goto next;
 885                 wait_on_buffer(bh);
 886                 if (!buffer_uptodate(bh)) {
 887                         /* read error, skip block & hope for the best */
 888                         ext4_error(sb, __FUNCTION__, "reading directory #%lu "
 889                                    "offset %lu", dir->i_ino, block);
 890                         brelse(bh);
 891                         goto next;
 892                 }
 893                 i = search_dirblock(bh, dir, dentry,
 894                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
 895                 if (i == 1) {
 896                         EXT4_I(dir)->i_dir_start_lookup = block;
 897                         ret = bh;
 898                         goto cleanup_and_exit;
 899                 } else {
 900                         brelse(bh);
 901                         if (i < 0)
 902                                 goto cleanup_and_exit;
 903                 }
 904         next:
 905                 if (++block >= nblocks)
 906                         block = 0;
 907         } while (block != start);
 908
 909         /*
 910          * If the directory has grown while we were searching, then
 911          * search the last part of the directory before giving up.
 912          */
 913         block = nblocks;
 914         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
 915         if (block < nblocks) {
 916                 start = 0;
 917                 goto restart;
 918         }
 919
 920 cleanup_and_exit:
 921         /* Clean up the read-ahead blocks */
 922         for (; ra_ptr < ra_max; ra_ptr++)
 923                 brelse (bh_use[ra_ptr]);
 924         return ret;
 925 }
 926
 927 #ifdef CONFIG_EXT4_INDEX
 928 static struct buffer_head * ext4_dx_find_entry(struct dentry *dentry,
 929                        struct ext4_dir_entry_2 **res_dir, int *err)
 930 {
 931         struct super_block * sb;
 932         struct dx_hash_info     hinfo;
 933         u32 hash;
 934         struct dx_frame frames[2], *frame;
 935         struct ext4_dir_entry_2 *de, *top;
 936         struct buffer_head *bh;
 937         unsigned long block;
 938         int retval;
 939         int namelen = dentry->d_name.len;
 940         const u8 *name = dentry->d_name.name;
 941         struct inode *dir = dentry->d_parent->d_inode;
 942
 943         sb = dir->i_sb;
 944         /* NFS may look up ".." - look at dx_root directory block */
 945         if (namelen > 2 || name[0] != '.'||(name[1] != '.' && name[1] != '\0')){
 946                 if (!(frame = dx_probe(dentry, NULL, &hinfo, frames, err)))
 947                         return NULL;
 948         } else {
 949                 frame = frames;
 950                 frame->bh = NULL;                       /* for dx_release() */
 951                 frame->at = (struct dx_entry *)frames;  /* hack for zero entry*/
 952                 dx_set_block(frame->at, 0);             /* dx_root block is 0 */
 953         }
 954         hash = hinfo.hash;
 955         do {
 956                 block = dx_get_block(frame->at);
 957                 if (!(bh = ext4_bread (NULL,dir, block, 0, err)))
 958                         goto errout;
 959                 de = (struct ext4_dir_entry_2 *) bh->b_data;
 960                 top = (struct ext4_dir_entry_2 *) ((char *) de + sb->s_blocksize -
 961                                        EXT4_DIR_REC_LEN(0));
 962                 for (; de < top; de = ext4_next_entry(de))
 963                 if (ext4_match (namelen, name, de)) {
 964                         if (!ext4_check_dir_entry("ext4_find_entry",
 965                                                   dir, de, bh,
 966                                   (block<<EXT4_BLOCK_SIZE_BITS(sb))
 967                                           +((char *)de - bh->b_data))) {
 968                                 brelse (bh);
 969                                 *err = ERR_BAD_DX_DIR;
 970                                 goto errout;
 971                         }
 972                         *res_dir = de;
 973                         dx_release (frames);
 974                         return bh;
 975                 }
 976                 brelse (bh);
 977                 /* Check to see if we should continue to search */
 978                 retval = ext4_htree_next_block(dir, hash, frame,
 979                                                frames, NULL);
 980                 if (retval < 0) {
 981                         ext4_warning(sb, __FUNCTION__,
 982                              "error reading index page in directory #%lu",
 983                              dir->i_ino);
 984                         *err = retval;
 985                         goto errout;
 986                 }
 987         } while (retval == 1);
 988
 989         *err = -ENOENT;
 990 errout:
 991         dxtrace(printk("%s not found\n", name));
 992         dx_release (frames);
 993         return NULL;
 994 }
 995 #endif
 996
 997 static struct dentry *ext4_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
 998 {
 999         struct inode * inode;
1000         struct ext4_dir_entry_2 * de;
1001         struct buffer_head * bh;
1002
1003         if (dentry->d_name.len > EXT4_NAME_LEN)
1004                 return ERR_PTR(-ENAMETOOLONG);
1005
1006         bh = ext4_find_entry(dentry, &de);
1007         inode = NULL;
1008         if (bh) {
1009                 unsigned long ino = le32_to_cpu(de->inode);
1010                 brelse (bh);
1011                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1012                         ext4_error(dir->i_sb, "ext4_lookup",
1013                                    "bad inode number: %lu", ino);
1014                         inode = NULL;
1015                 } else
1016                         inode = iget(dir->i_sb, ino);
1017
1018                 if (!inode)
1019                         return ERR_PTR(-EACCES);
1020         }
1021         return d_splice_alias(inode, dentry);
1022 }
1023
1024
1025 struct dentry *ext4_get_parent(struct dentry *child)
1026 {
1027         unsigned long ino;
1028         struct dentry *parent;
1029         struct inode *inode;
1030         struct dentry dotdot;
1031         struct ext4_dir_entry_2 * de;
1032         struct buffer_head *bh;
1033
1034         dotdot.d_name.name = "..";
1035         dotdot.d_name.len = 2;
1036         dotdot.d_parent = child; /* confusing, isn't it! */
1037
1038         bh = ext4_find_entry(&dotdot, &de);
1039         inode = NULL;
1040         if (!bh)
1041                 return ERR_PTR(-ENOENT);
1042         ino = le32_to_cpu(de->inode);
1043         brelse(bh);
1044
1045         if (!ext4_valid_inum(child->d_inode->i_sb, ino)) {
1046                 ext4_error(child->d_inode->i_sb, "ext4_get_parent",
1047                            "bad inode number: %lu", ino);
1048                 inode = NULL;
1049         } else
1050                 inode = iget(child->d_inode->i_sb, ino);
1051
1052         if (!inode)
1053                 return ERR_PTR(-EACCES);
1054
1055         parent = d_alloc_anon(inode);
1056         if (!parent) {
1057                 iput(inode);
1058                 parent = ERR_PTR(-ENOMEM);
1059         }
1060         return parent;
1061 }
1062
1063 #define S_SHIFT 12
1064 static unsigned char ext4_type_by_mode[S_IFMT >> S_SHIFT] = {
1065         [S_IFREG >> S_SHIFT]    = EXT4_FT_REG_FILE,
1066         [S_IFDIR >> S_SHIFT]    = EXT4_FT_DIR,
1067         [S_IFCHR >> S_SHIFT]    = EXT4_FT_CHRDEV,
1068         [S_IFBLK >> S_SHIFT]    = EXT4_FT_BLKDEV,
1069         [S_IFIFO >> S_SHIFT]    = EXT4_FT_FIFO,
1070         [S_IFSOCK >> S_SHIFT]   = EXT4_FT_SOCK,
1071         [S_IFLNK >> S_SHIFT]    = EXT4_FT_SYMLINK,
1072 };
1073
1074 static inline void ext4_set_de_type(struct super_block *sb,
1075                                 struct ext4_dir_entry_2 *de,
1076                                 umode_t mode) {
1077         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE))
1078                 de->file_type = ext4_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
1079 }
1080
1081 #ifdef CONFIG_EXT4_INDEX
1082 static struct ext4_dir_entry_2 *
1083 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count)
1084 {
1085         unsigned rec_len = 0;
1086
1087         while (count--) {
1088                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *) (from + map->offs);
1089                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1090                 memcpy (to, de, rec_len);
1091                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1092                                 cpu_to_le16(rec_len);
1093                 de->inode = 0;
1094                 map++;
1095                 to += rec_len;
1096         }
1097         return (struct ext4_dir_entry_2 *) (to - rec_len);
1098 }
1099
1100 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, int size)
1101 {
1102         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1103         unsigned rec_len = 0;
1104
1105         prev = to = de;
1106         while ((char*)de < base + size) {
1107                 next = (struct ext4_dir_entry_2 *) ((char *) de +
1108                                                     le16_to_cpu(de->rec_len));
1109                 if (de->inode && de->name_len) {
1110                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1111                         if (de > to)
1112                                 memmove(to, de, rec_len);
1113                         to->rec_len = cpu_to_le16(rec_len);
1114                         prev = to;
1115                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1116                 }
1117                 de = next;
1118         }
1119         return prev;
1120 }
1121
1122 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1123                         struct buffer_head **bh,struct dx_frame *frame,
1124                         struct dx_hash_info *hinfo, int *error)
1125 {
1126         unsigned blocksize = dir->i_sb->s_blocksize;
1127         unsigned count, continued;
1128         struct buffer_head *bh2;
1129         u32 newblock;
1130         u32 hash2;
1131         struct dx_map_entry *map;
1132         char *data1 = (*bh)->b_data, *data2;
1133         unsigned split;
1134         struct ext4_dir_entry_2 *de = NULL, *de2;
1135         int     err = 0;
1136
1137         bh2 = ext4_append (handle, dir, &newblock, &err);
1138         if (!(bh2)) {
1139                 brelse(*bh);
1140                 *bh = NULL;
1141                 goto errout;
1142         }
1143
1144         BUFFER_TRACE(*bh, "get_write_access");
1145         err = ext4_journal_get_write_access(handle, *bh);
1146         if (err)
1147                 goto journal_error;
1148
1149         BUFFER_TRACE(frame->bh, "get_write_access");
1150         err = ext4_journal_get_write_access(handle, frame->bh);
1151         if (err)
1152                 goto journal_error;
1153
1154         data2 = bh2->b_data;
1155
1156         /* create map in the end of data2 block */
1157         map = (struct dx_map_entry *) (data2 + blocksize);
1158         count = dx_make_map ((struct ext4_dir_entry_2 *) data1,
1159                              blocksize, hinfo, map);
1160         map -= count;
1161         split = count/2; // need to adjust to actual middle
1162         dx_sort_map (map, count);
1163         hash2 = map[split].hash;
1164         continued = hash2 == map[split - 1].hash;
1165         dxtrace(printk("Split block %i at %x, %i/%i\n",
1166                 dx_get_block(frame->at), hash2, split, count-split));
1167
1168         /* Fancy dance to stay within two buffers */
1169         de2 = dx_move_dirents(data1, data2, map + split, count - split);
1170         de = dx_pack_dirents(data1,blocksize);
1171         de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
1172         de2->rec_len = cpu_to_le16(data2 + blocksize - (char *) de2);
1173         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
1174         dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
1175
1176         /* Which block gets the new entry? */
1177         if (hinfo->hash >= hash2)
1178         {
1179                 swap(*bh, bh2);
1180                 de = de2;
1181         }
1182         dx_insert_block (frame, hash2 + continued, newblock);
1183         err = ext4_journal_dirty_metadata (handle, bh2);
1184         if (err)
1185                 goto journal_error;
1186         err = ext4_journal_dirty_metadata (handle, frame->bh);
1187         if (err)
1188                 goto journal_error;
1189         brelse (bh2);
1190         dxtrace(dx_show_index ("frame", frame->entries));
1191         return de;
1192
1193 journal_error:
1194         brelse(*bh);
1195         brelse(bh2);
1196         *bh = NULL;
1197         ext4_std_error(dir->i_sb, err);
1198 errout:
1199         *error = err;
1200         return NULL;
1201 }
1202 #endif
1203
1204
1205 /*
1206  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1207  * it points to a directory entry which is guaranteed to be large
1208  * enough for new directory entry.  If de is NULL, then
1209  * add_dirent_to_buf will attempt search the directory block for
1210  * space.  It will return -ENOSPC if no space is available, and -EIO
1211  * and -EEXIST if directory entry already exists.
1212  *
1213  * NOTE!  bh is NOT released in the case where ENOSPC is returned.  In
1214  * all other cases bh is released.
1215  */
1216 static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
1217                              struct inode *inode, struct ext4_dir_entry_2 *de,
1218                              struct buffer_head * bh)
1219 {
1220         struct inode    *dir = dentry->d_parent->d_inode;
1221         const char      *name = dentry->d_name.name;
1222         int             namelen = dentry->d_name.len;
1223         unsigned long   offset = 0;
1224         unsigned short  reclen;
1225         int             nlen, rlen, err;
1226         char            *top;
1227
1228         reclen = EXT4_DIR_REC_LEN(namelen);
1229         if (!de) {
1230                 de = (struct ext4_dir_entry_2 *)bh->b_data;
1231                 top = bh->b_data + dir->i_sb->s_blocksize - reclen;
1232                 while ((char *) de <= top) {
1233                         if (!ext4_check_dir_entry("ext4_add_entry", dir, de,
1234                                                   bh, offset)) {
1235                                 brelse (bh);
1236                                 return -EIO;
1237                         }
1238                         if (ext4_match (namelen, name, de)) {
1239                                 brelse (bh);
1240                                 return -EEXIST;
1241                         }
1242                         nlen = EXT4_DIR_REC_LEN(de->name_len);
1243                         rlen = le16_to_cpu(de->rec_len);
1244                         if ((de->inode? rlen - nlen: rlen) >= reclen)
1245                                 break;
1246                         de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1247                         offset += rlen;
1248                 }
1249                 if ((char *) de > top)
1250                         return -ENOSPC;
1251         }
1252         BUFFER_TRACE(bh, "get_write_access");
1253         err = ext4_journal_get_write_access(handle, bh);
1254         if (err) {
1255                 ext4_std_error(dir->i_sb, err);
1256                 brelse(bh);
1257                 return err;
1258         }
1259
1260         /* By now the buffer is marked for journaling */
1261         nlen = EXT4_DIR_REC_LEN(de->name_len);
1262         rlen = le16_to_cpu(de->rec_len);
1263         if (de->inode) {
1264                 struct ext4_dir_entry_2 *de1 = (struct ext4_dir_entry_2 *)((char *)de + nlen);
1265                 de1->rec_len = cpu_to_le16(rlen - nlen);
1266                 de->rec_len = cpu_to_le16(nlen);
1267                 de = de1;
1268         }
1269         de->file_type = EXT4_FT_UNKNOWN;
1270         if (inode) {
1271                 de->inode = cpu_to_le32(inode->i_ino);
1272                 ext4_set_de_type(dir->i_sb, de, inode->i_mode);
1273         } else
1274                 de->inode = 0;
1275         de->name_len = namelen;
1276         memcpy (de->name, name, namelen);
1277         /*
1278          * XXX shouldn't update any times until successful
1279          * completion of syscall, but too many callers depend
1280          * on this.
1281          *
1282          * XXX similarly, too many callers depend on
1283          * ext4_new_inode() setting the times, but error
1284          * recovery deletes the inode, so the worst that can
1285          * happen is that the times are slightly out of date
1286          * and/or different from the directory change time.
1287          */
1288         dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
1289         ext4_update_dx_flag(dir);
1290         dir->i_version++;
1291         ext4_mark_inode_dirty(handle, dir);
1292         BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
1293         err = ext4_journal_dirty_metadata(handle, bh);
1294         if (err)
1295                 ext4_std_error(dir->i_sb, err);
1296         brelse(bh);
1297         return 0;
1298 }
1299
1300 #ifdef CONFIG_EXT4_INDEX
1301 /*
1302  * This converts a one block unindexed directory to a 3 block indexed
1303  * directory, and adds the dentry to the indexed directory.
1304  */
1305 static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1306                             struct inode *inode, struct buffer_head *bh)
1307 {
1308         struct inode    *dir = dentry->d_parent->d_inode;
1309         const char      *name = dentry->d_name.name;
1310         int             namelen = dentry->d_name.len;
1311         struct buffer_head *bh2;
1312         struct dx_root  *root;
1313         struct dx_frame frames[2], *frame;
1314         struct dx_entry *entries;
1315         struct ext4_dir_entry_2 *de, *de2;
1316         char            *data1, *top;
1317         unsigned        len;
1318         int             retval;
1319         unsigned        blocksize;
1320         struct dx_hash_info hinfo;
1321         u32             block;
1322         struct fake_dirent *fde;
1323
1324         blocksize =  dir->i_sb->s_blocksize;
1325         dxtrace(printk("Creating index\n"));
1326         retval = ext4_journal_get_write_access(handle, bh);
1327         if (retval) {
1328                 ext4_std_error(dir->i_sb, retval);
1329                 brelse(bh);
1330                 return retval;
1331         }
1332         root = (struct dx_root *) bh->b_data;
1333
1334         bh2 = ext4_append (handle, dir, &block, &retval);
1335         if (!(bh2)) {
1336                 brelse(bh);
1337                 return retval;
1338         }
1339         EXT4_I(dir)->i_flags |= EXT4_INDEX_FL;
1340         data1 = bh2->b_data;
1341
1342         /* The 0th block becomes the root, move the dirents out */
1343         fde = &root->dotdot;
1344         de = (struct ext4_dir_entry_2 *)((char *)fde + le16_to_cpu(fde->rec_len));
1345         len = ((char *) root) + blocksize - (char *) de;
1346         memcpy (data1, de, len);
1347         de = (struct ext4_dir_entry_2 *) data1;
1348         top = data1 + len;
1349         while ((char *)(de2=(void*)de+le16_to_cpu(de->rec_len)) < top)
1350                 de = de2;
1351         de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
1352         /* Initialize the root; the dot dirents already exist */
1353         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1354         de->rec_len = cpu_to_le16(blocksize - EXT4_DIR_REC_LEN(2));
1355         memset (&root->info, 0, sizeof(root->info));
1356         root->info.info_length = sizeof(root->info);
1357         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1358         entries = root->entries;
1359         dx_set_block (entries, 1);
1360         dx_set_count (entries, 1);
1361         dx_set_limit (entries, dx_root_limit(dir, sizeof(root->info)));
1362
1363         /* Initialize as for dx_probe */
1364         hinfo.hash_version = root->info.hash_version;
1365         hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1366         ext4fs_dirhash(name, namelen, &hinfo);
1367         frame = frames;
1368         frame->entries = entries;
1369         frame->at = entries;
1370         frame->bh = bh;
1371         bh = bh2;
1372         de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
1373         dx_release (frames);
1374         if (!(de))
1375                 return retval;
1376
1377         return add_dirent_to_buf(handle, dentry, inode, de, bh);
1378 }
1379 #endif
1380
1381 /*
1382  *      ext4_add_entry()
1383  *
1384  * adds a file entry to the specified directory, using the same
1385  * semantics as ext4_find_entry(). It returns NULL if it failed.
1386  *
1387  * NOTE!! The inode part of 'de' is left at 0 - which means you
1388  * may not sleep between calling this and putting something into
1389  * the entry, as someone else might have used it while you slept.
1390  */
1391 static int ext4_add_entry (handle_t *handle, struct dentry *dentry,
1392         struct inode *inode)
1393 {
1394         struct inode *dir = dentry->d_parent->d_inode;
1395         unsigned long offset;
1396         struct buffer_head * bh;
1397         struct ext4_dir_entry_2 *de;
1398         struct super_block * sb;
1399         int     retval;
1400 #ifdef CONFIG_EXT4_INDEX
1401         int     dx_fallback=0;
1402 #endif
1403         unsigned blocksize;
1404         u32 block, blocks;
1405
1406         sb = dir->i_sb;
1407         blocksize = sb->s_blocksize;
1408         if (!dentry->d_name.len)
1409                 return -EINVAL;
1410 #ifdef CONFIG_EXT4_INDEX
1411         if (is_dx(dir)) {
1412                 retval = ext4_dx_add_entry(handle, dentry, inode);
1413                 if (!retval || (retval != ERR_BAD_DX_DIR))
1414                         return retval;
1415                 EXT4_I(dir)->i_flags &= ~EXT4_INDEX_FL;
1416                 dx_fallback++;
1417                 ext4_mark_inode_dirty(handle, dir);
1418         }
1419 #endif
1420         blocks = dir->i_size >> sb->s_blocksize_bits;
1421         for (block = 0, offset = 0; block < blocks; block++) {
1422                 bh = ext4_bread(handle, dir, block, 0, &retval);
1423                 if(!bh)
1424                         return retval;
1425                 retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1426                 if (retval != -ENOSPC)
1427                         return retval;
1428
1429 #ifdef CONFIG_EXT4_INDEX
1430                 if (blocks == 1 && !dx_fallback &&
1431                     EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX))
1432                         return make_indexed_dir(handle, dentry, inode, bh);
1433 #endif
1434                 brelse(bh);
1435         }
1436         bh = ext4_append(handle, dir, &block, &retval);
1437         if (!bh)
1438                 return retval;
1439         de = (struct ext4_dir_entry_2 *) bh->b_data;
1440         de->inode = 0;
1441         de->rec_len = cpu_to_le16(blocksize);
1442         return add_dirent_to_buf(handle, dentry, inode, de, bh);
1443 }
1444
1445 #ifdef CONFIG_EXT4_INDEX
1446 /*
1447  * Returns 0 for success, or a negative error value
1448  */
1449 static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
1450                              struct inode *inode)
1451 {
1452         struct dx_frame frames[2], *frame;
1453         struct dx_entry *entries, *at;
1454         struct dx_hash_info hinfo;
1455         struct buffer_head * bh;
1456         struct inode *dir = dentry->d_parent->d_inode;
1457         struct super_block * sb = dir->i_sb;
1458         struct ext4_dir_entry_2 *de;
1459         int err;
1460
1461         frame = dx_probe(dentry, NULL, &hinfo, frames, &err);
1462         if (!frame)
1463                 return err;
1464         entries = frame->entries;
1465         at = frame->at;
1466
1467         if (!(bh = ext4_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
1468                 goto cleanup;
1469
1470         BUFFER_TRACE(bh, "get_write_access");
1471         err = ext4_journal_get_write_access(handle, bh);
1472         if (err)
1473                 goto journal_error;
1474
1475         err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
1476         if (err != -ENOSPC) {
1477                 bh = NULL;
1478                 goto cleanup;
1479         }
1480
1481         /* Block full, should compress but for now just split */
1482         dxtrace(printk("using %u of %u node entries\n",
1483                        dx_get_count(entries), dx_get_limit(entries)));
1484         /* Need to split index? */
1485         if (dx_get_count(entries) == dx_get_limit(entries)) {
1486                 u32 newblock;
1487                 unsigned icount = dx_get_count(entries);
1488                 int levels = frame - frames;
1489                 struct dx_entry *entries2;
1490                 struct dx_node *node2;
1491                 struct buffer_head *bh2;
1492
1493                 if (levels && (dx_get_count(frames->entries) ==
1494                                dx_get_limit(frames->entries))) {
1495                         ext4_warning(sb, __FUNCTION__,
1496                                      "Directory index full!");
1497                         err = -ENOSPC;
1498                         goto cleanup;
1499                 }
1500                 bh2 = ext4_append (handle, dir, &newblock, &err);
1501                 if (!(bh2))
1502                         goto cleanup;
1503                 node2 = (struct dx_node *)(bh2->b_data);
1504                 entries2 = node2->entries;
1505                 node2->fake.rec_len = cpu_to_le16(sb->s_blocksize);
1506                 node2->fake.inode = 0;
1507                 BUFFER_TRACE(frame->bh, "get_write_access");
1508                 err = ext4_journal_get_write_access(handle, frame->bh);
1509                 if (err)
1510                         goto journal_error;
1511                 if (levels) {
1512                         unsigned icount1 = icount/2, icount2 = icount - icount1;
1513                         unsigned hash2 = dx_get_hash(entries + icount1);
1514                         dxtrace(printk("Split index %i/%i\n", icount1, icount2));
1515
1516                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
1517                         err = ext4_journal_get_write_access(handle,
1518                                                              frames[0].bh);
1519                         if (err)
1520                                 goto journal_error;
1521
1522                         memcpy ((char *) entries2, (char *) (entries + icount1),
1523                                 icount2 * sizeof(struct dx_entry));
1524                         dx_set_count (entries, icount1);
1525                         dx_set_count (entries2, icount2);
1526                         dx_set_limit (entries2, dx_node_limit(dir));
1527
1528                         /* Which index block gets the new entry? */
1529                         if (at - entries >= icount1) {
1530                                 frame->at = at = at - entries - icount1 + entries2;
1531                                 frame->entries = entries = entries2;
1532                                 swap(frame->bh, bh2);
1533                         }
1534                         dx_insert_block (frames + 0, hash2, newblock);
1535                         dxtrace(dx_show_index ("node", frames[1].entries));
1536                         dxtrace(dx_show_index ("node",
1537                                ((struct dx_node *) bh2->b_data)->entries));
1538                         err = ext4_journal_dirty_metadata(handle, bh2);
1539                         if (err)
1540                                 goto journal_error;
1541                         brelse (bh2);
1542                 } else {
1543                         dxtrace(printk("Creating second level index...\n"));
1544                         memcpy((char *) entries2, (char *) entries,
1545                                icount * sizeof(struct dx_entry));
1546                         dx_set_limit(entries2, dx_node_limit(dir));
1547
1548                         /* Set up root */
1549                         dx_set_count(entries, 1);
1550                         dx_set_block(entries + 0, newblock);
1551                         ((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
1552
1553                         /* Add new access path frame */
1554                         frame = frames + 1;
1555                         frame->at = at = at - entries + entries2;
1556                         frame->entries = entries = entries2;
1557                         frame->bh = bh2;
1558                         err = ext4_journal_get_write_access(handle,
1559                                                              frame->bh);
1560                         if (err)
1561                                 goto journal_error;
1562                 }
1563                 ext4_journal_dirty_metadata(handle, frames[0].bh);
1564         }
1565         de = do_split(handle, dir, &bh, frame, &hinfo, &err);
1566         if (!de)
1567                 goto cleanup;
1568         err = add_dirent_to_buf(handle, dentry, inode, de, bh);
1569         bh = NULL;
1570         goto cleanup;
1571
1572 journal_error:
1573         ext4_std_error(dir->i_sb, err);
1574 cleanup:
1575         if (bh)
1576                 brelse(bh);
1577         dx_release(frames);
1578         return err;
1579 }
1580 #endif
1581
1582 /*
1583  * ext4_delete_entry deletes a directory entry by merging it with the
1584  * previous entry
1585  */
1586 static int ext4_delete_entry (handle_t *handle,
1587                               struct inode * dir,
1588                               struct ext4_dir_entry_2 * de_del,
1589                               struct buffer_head * bh)
1590 {
1591         struct ext4_dir_entry_2 * de, * pde;
1592         int i;
1593
1594         i = 0;
1595         pde = NULL;
1596         de = (struct ext4_dir_entry_2 *) bh->b_data;
1597         while (i < bh->b_size) {
1598                 if (!ext4_check_dir_entry("ext4_delete_entry", dir, de, bh, i))
1599                         return -EIO;
1600                 if (de == de_del)  {
1601                         BUFFER_TRACE(bh, "get_write_access");
1602                         ext4_journal_get_write_access(handle, bh);
1603                         if (pde)
1604                                 pde->rec_len =
1605                                         cpu_to_le16(le16_to_cpu(pde->rec_len) +
1606                                                     le16_to_cpu(de->rec_len));
1607                         else
1608                                 de->inode = 0;
1609                         dir->i_version++;
1610                         BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
1611                         ext4_journal_dirty_metadata(handle, bh);
1612                         return 0;
1613                 }
1614                 i += le16_to_cpu(de->rec_len);
1615                 pde = de;
1616                 de = (struct ext4_dir_entry_2 *)
1617                         ((char *) de + le16_to_cpu(de->rec_len));
1618         }
1619         return -ENOENT;
1620 }
1621
1622 static int ext4_add_nondir(handle_t *handle,
1623                 struct dentry *dentry, struct inode *inode)
1624 {
1625         int err = ext4_add_entry(handle, dentry, inode);
1626         if (!err) {
1627                 ext4_mark_inode_dirty(handle, inode);
1628                 d_instantiate(dentry, inode);
1629                 return 0;
1630         }
1631         drop_nlink(inode);
1632         iput(inode);
1633         return err;
1634 }
1635
1636 /*
1637  * By the time this is called, we already have created
1638  * the directory cache entry for the new file, but it
1639  * is so far negative - it has no inode.
1640  *
1641  * If the create succeeds, we fill in the inode information
1642  * with d_instantiate().
1643  */
1644 static int ext4_create (struct inode * dir, struct dentry * dentry, int mode,
1645                 struct nameidata *nd)
1646 {
1647         handle_t *handle;
1648         struct inode * inode;
1649         int err, retries = 0;
1650
1651 retry:
1652         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
1653                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
1654                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
1655         if (IS_ERR(handle))
1656                 return PTR_ERR(handle);
1657
1658         if (IS_DIRSYNC(dir))
1659                 handle->h_sync = 1;
1660
1661         inode = ext4_new_inode (handle, dir, mode);
1662         err = PTR_ERR(inode);
1663         if (!IS_ERR(inode)) {
1664                 inode->i_op = &ext4_file_inode_operations;
1665                 inode->i_fop = &ext4_file_operations;
1666                 ext4_set_aops(inode);
1667                 err = ext4_add_nondir(handle, dentry, inode);
1668         }
1669         ext4_journal_stop(handle);
1670         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
1671                 goto retry;
1672         return err;
1673 }
1674
1675 static int ext4_mknod (struct inode * dir, struct dentry *dentry,
1676                         int mode, dev_t rdev)
1677 {
1678         handle_t *handle;
1679         struct inode *inode;
1680         int err, retries = 0;
1681
1682         if (!new_valid_dev(rdev))
1683                 return -EINVAL;
1684
1685 retry:
1686         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
1687                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
1688                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
1689         if (IS_ERR(handle))
1690                 return PTR_ERR(handle);
1691
1692         if (IS_DIRSYNC(dir))
1693                 handle->h_sync = 1;
1694
1695         inode = ext4_new_inode (handle, dir, mode);
1696         err = PTR_ERR(inode);
1697         if (!IS_ERR(inode)) {
1698                 init_special_inode(inode, inode->i_mode, rdev);
1699 #ifdef CONFIG_EXT4DEV_FS_XATTR
1700                 inode->i_op = &ext4_special_inode_operations;
1701 #endif
1702                 err = ext4_add_nondir(handle, dentry, inode);
1703         }
1704         ext4_journal_stop(handle);
1705         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
1706                 goto retry;
1707         return err;
1708 }
1709
1710 static int ext4_mkdir(struct inode * dir, struct dentry * dentry, int mode)
1711 {
1712         handle_t *handle;
1713         struct inode * inode;
1714         struct buffer_head * dir_block;
1715         struct ext4_dir_entry_2 * de;
1716         int err, retries = 0;
1717
1718         if (dir->i_nlink >= EXT4_LINK_MAX)
1719                 return -EMLINK;
1720
1721 retry:
1722         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
1723                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
1724                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
1725         if (IS_ERR(handle))
1726                 return PTR_ERR(handle);
1727
1728         if (IS_DIRSYNC(dir))
1729                 handle->h_sync = 1;
1730
1731         inode = ext4_new_inode (handle, dir, S_IFDIR | mode);
1732         err = PTR_ERR(inode);
1733         if (IS_ERR(inode))
1734                 goto out_stop;
1735
1736         inode->i_op = &ext4_dir_inode_operations;
1737         inode->i_fop = &ext4_dir_operations;
1738         inode->i_size = EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
1739         dir_block = ext4_bread (handle, inode, 0, 1, &err);
1740         if (!dir_block) {
1741                 drop_nlink(inode); /* is this nlink == 0? */
1742                 ext4_mark_inode_dirty(handle, inode);
1743                 iput (inode);
1744                 goto out_stop;
1745         }
1746         BUFFER_TRACE(dir_block, "get_write_access");
1747         ext4_journal_get_write_access(handle, dir_block);
1748         de = (struct ext4_dir_entry_2 *) dir_block->b_data;
1749         de->inode = cpu_to_le32(inode->i_ino);
1750         de->name_len = 1;
1751         de->rec_len = cpu_to_le16(EXT4_DIR_REC_LEN(de->name_len));
1752         strcpy (de->name, ".");
1753         ext4_set_de_type(dir->i_sb, de, S_IFDIR);
1754         de = (struct ext4_dir_entry_2 *)
1755                         ((char *) de + le16_to_cpu(de->rec_len));
1756         de->inode = cpu_to_le32(dir->i_ino);
1757         de->rec_len = cpu_to_le16(inode->i_sb->s_blocksize-EXT4_DIR_REC_LEN(1));
1758         de->name_len = 2;
1759         strcpy (de->name, "..");
1760         ext4_set_de_type(dir->i_sb, de, S_IFDIR);
1761         inode->i_nlink = 2;
1762         BUFFER_TRACE(dir_block, "call ext4_journal_dirty_metadata");
1763         ext4_journal_dirty_metadata(handle, dir_block);
1764         brelse (dir_block);
1765         ext4_mark_inode_dirty(handle, inode);
1766         err = ext4_add_entry (handle, dentry, inode);
1767         if (err) {
1768                 inode->i_nlink = 0;
1769                 ext4_mark_inode_dirty(handle, inode);
1770                 iput (inode);
1771                 goto out_stop;
1772         }
1773         inc_nlink(dir);
1774         ext4_update_dx_flag(dir);
1775         ext4_mark_inode_dirty(handle, dir);
1776         d_instantiate(dentry, inode);
1777 out_stop:
1778         ext4_journal_stop(handle);
1779         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
1780                 goto retry;
1781         return err;
1782 }
1783
1784 /*
1785  * routine to check that the specified directory is empty (for rmdir)
1786  */
1787 static int empty_dir (struct inode * inode)
1788 {
1789         unsigned long offset;
1790         struct buffer_head * bh;
1791         struct ext4_dir_entry_2 * de, * de1;
1792         struct super_block * sb;
1793         int err = 0;
1794
1795         sb = inode->i_sb;
1796         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2) ||
1797             !(bh = ext4_bread (NULL, inode, 0, 0, &err))) {
1798                 if (err)
1799                         ext4_error(inode->i_sb, __FUNCTION__,
1800                                    "error %d reading directory #%lu offset 0",
1801                                    err, inode->i_ino);
1802                 else
1803                         ext4_warning(inode->i_sb, __FUNCTION__,
1804                                      "bad directory (dir #%lu) - no data block",
1805                                      inode->i_ino);
1806                 return 1;
1807         }
1808         de = (struct ext4_dir_entry_2 *) bh->b_data;
1809         de1 = (struct ext4_dir_entry_2 *)
1810                         ((char *) de + le16_to_cpu(de->rec_len));
1811         if (le32_to_cpu(de->inode) != inode->i_ino ||
1812                         !le32_to_cpu(de1->inode) ||
1813                         strcmp (".", de->name) ||
1814                         strcmp ("..", de1->name)) {
1815                 ext4_warning (inode->i_sb, "empty_dir",
1816                               "bad directory (dir #%lu) - no `.' or `..'",
1817                               inode->i_ino);
1818                 brelse (bh);
1819                 return 1;
1820         }
1821         offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
1822         de = (struct ext4_dir_entry_2 *)
1823                         ((char *) de1 + le16_to_cpu(de1->rec_len));
1824         while (offset < inode->i_size ) {
1825                 if (!bh ||
1826                         (void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
1827                         err = 0;
1828                         brelse (bh);
1829                         bh = ext4_bread (NULL, inode,
1830                                 offset >> EXT4_BLOCK_SIZE_BITS(sb), 0, &err);
1831                         if (!bh) {
1832                                 if (err)
1833                                         ext4_error(sb, __FUNCTION__,
1834                                                    "error %d reading directory"
1835                                                    " #%lu offset %lu",
1836                                                    err, inode->i_ino, offset);
1837                                 offset += sb->s_blocksize;
1838                                 continue;
1839                         }
1840                         de = (struct ext4_dir_entry_2 *) bh->b_data;
1841                 }
1842                 if (!ext4_check_dir_entry("empty_dir", inode, de, bh, offset)) {
1843                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
1844                                                          sb->s_blocksize);
1845                         offset = (offset | (sb->s_blocksize - 1)) + 1;
1846                         continue;
1847                 }
1848                 if (le32_to_cpu(de->inode)) {
1849                         brelse (bh);
1850                         return 0;
1851                 }
1852                 offset += le16_to_cpu(de->rec_len);
1853                 de = (struct ext4_dir_entry_2 *)
1854                                 ((char *) de + le16_to_cpu(de->rec_len));
1855         }
1856         brelse (bh);
1857         return 1;
1858 }
1859
1860 /* ext4_orphan_add() links an unlinked or truncated inode into a list of
1861  * such inodes, starting at the superblock, in case we crash before the
1862  * file is closed/deleted, or in case the inode truncate spans multiple
1863  * transactions and the last transaction is not recovered after a crash.
1864  *
1865  * At filesystem recovery time, we walk this list deleting unlinked
1866  * inodes and truncating linked inodes in ext4_orphan_cleanup().
1867  */
1868 int ext4_orphan_add(handle_t *handle, struct inode *inode)
1869 {
1870         struct super_block *sb = inode->i_sb;
1871         struct ext4_iloc iloc;
1872         int err = 0, rc;
1873
1874         lock_super(sb);
1875         if (!list_empty(&EXT4_I(inode)->i_orphan))
1876                 goto out_unlock;
1877
1878         /* Orphan handling is only valid for files with data blocks
1879          * being truncated, or files being unlinked. */
1880
1881         /* @@@ FIXME: Observation from aviro:
1882          * I think I can trigger J_ASSERT in ext4_orphan_add().  We block
1883          * here (on lock_super()), so race with ext4_link() which might bump
1884          * ->i_nlink. For, say it, character device. Not a regular file,
1885          * not a directory, not a symlink and ->i_nlink > 0.
1886          */
1887         J_ASSERT ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1888                 S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
1889
1890         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1891         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1892         if (err)
1893                 goto out_unlock;
1894
1895         err = ext4_reserve_inode_write(handle, inode, &iloc);
1896         if (err)
1897                 goto out_unlock;
1898
1899         /* Insert this inode at the head of the on-disk orphan list... */
1900         NEXT_ORPHAN(inode) = le32_to_cpu(EXT4_SB(sb)->s_es->s_last_orphan);
1901         EXT4_SB(sb)->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
1902         err = ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
1903         rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
1904         if (!err)
1905                 err = rc;
1906
1907         /* Only add to the head of the in-memory list if all the
1908          * previous operations succeeded.  If the orphan_add is going to
1909          * fail (possibly taking the journal offline), we can't risk
1910          * leaving the inode on the orphan list: stray orphan-list
1911          * entries can cause panics at unmount time.
1912          *
1913          * This is safe: on error we're going to ignore the orphan list
1914          * anyway on the next recovery. */
1915         if (!err)
1916                 list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
1917
1918         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
1919         jbd_debug(4, "orphan inode %lu will point to %d\n",
1920                         inode->i_ino, NEXT_ORPHAN(inode));
1921 out_unlock:
1922         unlock_super(sb);
1923         ext4_std_error(inode->i_sb, err);
1924         return err;
1925 }
1926
1927 /*
1928  * ext4_orphan_del() removes an unlinked or truncated inode from the list
1929  * of such inodes stored on disk, because it is finally being cleaned up.
1930  */
1931 int ext4_orphan_del(handle_t *handle, struct inode *inode)
1932 {
1933         struct list_head *prev;
1934         struct ext4_inode_info *ei = EXT4_I(inode);
1935         struct ext4_sb_info *sbi;
1936         unsigned long ino_next;
1937         struct ext4_iloc iloc;
1938         int err = 0;
1939
1940         lock_super(inode->i_sb);
1941         if (list_empty(&ei->i_orphan)) {
1942                 unlock_super(inode->i_sb);
1943                 return 0;
1944         }
1945
1946         ino_next = NEXT_ORPHAN(inode);
1947         prev = ei->i_orphan.prev;
1948         sbi = EXT4_SB(inode->i_sb);
1949
1950         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
1951
1952         list_del_init(&ei->i_orphan);
1953
1954         /* If we're on an error path, we may not have a valid
1955          * transaction handle with which to update the orphan list on
1956          * disk, but we still need to remove the inode from the linked
1957          * list in memory. */
1958         if (!handle)
1959                 goto out;
1960
1961         err = ext4_reserve_inode_write(handle, inode, &iloc);
1962         if (err)
1963                 goto out_err;
1964
1965         if (prev == &sbi->s_orphan) {
1966                 jbd_debug(4, "superblock will point to %lu\n", ino_next);
1967                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1968                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1969                 if (err)
1970                         goto out_brelse;
1971                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
1972                 err = ext4_journal_dirty_metadata(handle, sbi->s_sbh);
1973         } else {
1974                 struct ext4_iloc iloc2;
1975                 struct inode *i_prev =
1976                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
1977
1978                 jbd_debug(4, "orphan inode %lu will point to %lu\n",
1979                           i_prev->i_ino, ino_next);
1980                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
1981                 if (err)
1982                         goto out_brelse;
1983                 NEXT_ORPHAN(i_prev) = ino_next;
1984                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
1985         }
1986         if (err)
1987                 goto out_brelse;
1988         NEXT_ORPHAN(inode) = 0;
1989         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
1990
1991 out_err:
1992         ext4_std_error(inode->i_sb, err);
1993 out:
1994         unlock_super(inode->i_sb);
1995         return err;
1996
1997 out_brelse:
1998         brelse(iloc.bh);
1999         goto out_err;
2000 }
2001
2002 static int ext4_rmdir (struct inode * dir, struct dentry *dentry)
2003 {
2004         int retval;
2005         struct inode * inode;
2006         struct buffer_head * bh;
2007         struct ext4_dir_entry_2 * de;
2008         handle_t *handle;
2009
2010         /* Initialize quotas before so that eventual writes go in
2011          * separate transaction */
2012         DQUOT_INIT(dentry->d_inode);
2013         handle = ext4_journal_start(dir, EXT4_DELETE_TRANS_BLOCKS(dir->i_sb));
2014         if (IS_ERR(handle))
2015                 return PTR_ERR(handle);
2016
2017         retval = -ENOENT;
2018         bh = ext4_find_entry (dentry, &de);
2019         if (!bh)
2020                 goto end_rmdir;
2021
2022         if (IS_DIRSYNC(dir))
2023                 handle->h_sync = 1;
2024
2025         inode = dentry->d_inode;
2026
2027         retval = -EIO;
2028         if (le32_to_cpu(de->inode) != inode->i_ino)
2029                 goto end_rmdir;
2030
2031         retval = -ENOTEMPTY;
2032         if (!empty_dir (inode))
2033                 goto end_rmdir;
2034
2035         retval = ext4_delete_entry(handle, dir, de, bh);
2036         if (retval)
2037                 goto end_rmdir;
2038         if (inode->i_nlink != 2)
2039                 ext4_warning (inode->i_sb, "ext4_rmdir",
2040                               "empty directory has nlink!=2 (%d)",
2041                               inode->i_nlink);
2042         inode->i_version++;
2043         clear_nlink(inode);
2044         /* There's no need to set i_disksize: the fact that i_nlink is
2045          * zero will ensure that the right thing happens during any
2046          * recovery. */
2047         inode->i_size = 0;
2048         ext4_orphan_add(handle, inode);
2049         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
2050         ext4_mark_inode_dirty(handle, inode);
2051         drop_nlink(dir);
2052         ext4_update_dx_flag(dir);
2053         ext4_mark_inode_dirty(handle, dir);
2054
2055 end_rmdir:
2056         ext4_journal_stop(handle);
2057         brelse (bh);
2058         return retval;
2059 }
2060
2061 static int ext4_unlink(struct inode * dir, struct dentry *dentry)
2062 {
2063         int retval;
2064         struct inode * inode;
2065         struct buffer_head * bh;
2066         struct ext4_dir_entry_2 * de;
2067         handle_t *handle;
2068
2069         /* Initialize quotas before so that eventual writes go
2070          * in separate transaction */
2071         DQUOT_INIT(dentry->d_inode);
2072         handle = ext4_journal_start(dir, EXT4_DELETE_TRANS_BLOCKS(dir->i_sb));
2073         if (IS_ERR(handle))
2074                 return PTR_ERR(handle);
2075
2076         if (IS_DIRSYNC(dir))
2077                 handle->h_sync = 1;
2078
2079         retval = -ENOENT;
2080         bh = ext4_find_entry (dentry, &de);
2081         if (!bh)
2082                 goto end_unlink;
2083
2084         inode = dentry->d_inode;
2085
2086         retval = -EIO;
2087         if (le32_to_cpu(de->inode) != inode->i_ino)
2088                 goto end_unlink;
2089
2090         if (!inode->i_nlink) {
2091                 ext4_warning (inode->i_sb, "ext4_unlink",
2092                               "Deleting nonexistent file (%lu), %d",
2093                               inode->i_ino, inode->i_nlink);
2094                 inode->i_nlink = 1;
2095         }
2096         retval = ext4_delete_entry(handle, dir, de, bh);
2097         if (retval)
2098                 goto end_unlink;
2099         dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
2100         ext4_update_dx_flag(dir);
2101         ext4_mark_inode_dirty(handle, dir);
2102         drop_nlink(inode);
2103         if (!inode->i_nlink)
2104                 ext4_orphan_add(handle, inode);
2105         inode->i_ctime = dir->i_ctime;
2106         ext4_mark_inode_dirty(handle, inode);
2107         retval = 0;
2108
2109 end_unlink:
2110         ext4_journal_stop(handle);
2111         brelse (bh);
2112         return retval;
2113 }
2114
2115 static int ext4_symlink (struct inode * dir,
2116                 struct dentry *dentry, const char * symname)
2117 {
2118         handle_t *handle;
2119         struct inode * inode;
2120         int l, err, retries = 0;
2121
2122         l = strlen(symname)+1;
2123         if (l > dir->i_sb->s_blocksize)
2124                 return -ENAMETOOLONG;
2125
2126 retry:
2127         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2128                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 5 +
2129                                         2*EXT4_QUOTA_INIT_BLOCKS(dir->i_sb));
2130         if (IS_ERR(handle))
2131                 return PTR_ERR(handle);
2132
2133         if (IS_DIRSYNC(dir))
2134                 handle->h_sync = 1;
2135
2136         inode = ext4_new_inode (handle, dir, S_IFLNK|S_IRWXUGO);
2137         err = PTR_ERR(inode);
2138         if (IS_ERR(inode))
2139                 goto out_stop;
2140
2141         if (l > sizeof (EXT4_I(inode)->i_data)) {
2142                 inode->i_op = &ext4_symlink_inode_operations;
2143                 ext4_set_aops(inode);
2144                 /*
2145                  * page_symlink() calls into ext4_prepare/commit_write.
2146                  * We have a transaction open.  All is sweetness.  It also sets
2147                  * i_size in generic_commit_write().
2148                  */
2149                 err = __page_symlink(inode, symname, l,
2150                                 mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
2151                 if (err) {
2152                         drop_nlink(inode);
2153                         ext4_mark_inode_dirty(handle, inode);
2154                         iput (inode);
2155                         goto out_stop;
2156                 }
2157         } else {
2158                 inode->i_op = &ext4_fast_symlink_inode_operations;
2159                 memcpy((char*)&EXT4_I(inode)->i_data,symname,l);
2160                 inode->i_size = l-1;
2161         }
2162         EXT4_I(inode)->i_disksize = inode->i_size;
2163         err = ext4_add_nondir(handle, dentry, inode);
2164 out_stop:
2165         ext4_journal_stop(handle);
2166         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2167                 goto retry;
2168         return err;
2169 }
2170
2171 static int ext4_link (struct dentry * old_dentry,
2172                 struct inode * dir, struct dentry *dentry)
2173 {
2174         handle_t *handle;
2175         struct inode *inode = old_dentry->d_inode;
2176         int err, retries = 0;
2177
2178         if (inode->i_nlink >= EXT4_LINK_MAX)
2179                 return -EMLINK;
2180         /*
2181          * Return -ENOENT if we've raced with unlink and i_nlink is 0.  Doing
2182          * otherwise has the potential to corrupt the orphan inode list.
2183          */
2184         if (inode->i_nlink == 0)
2185                 return -ENOENT;
2186
2187 retry:
2188         handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2189                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS);
2190         if (IS_ERR(handle))
2191                 return PTR_ERR(handle);
2192
2193         if (IS_DIRSYNC(dir))
2194                 handle->h_sync = 1;
2195
2196         inode->i_ctime = CURRENT_TIME_SEC;
2197         inc_nlink(inode);
2198         atomic_inc(&inode->i_count);
2199
2200         err = ext4_add_nondir(handle, dentry, inode);
2201         ext4_journal_stop(handle);
2202         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2203                 goto retry;
2204         return err;
2205 }
2206
2207 #define PARENT_INO(buffer) \
2208         ((struct ext4_dir_entry_2 *) ((char *) buffer + \
2209         le16_to_cpu(((struct ext4_dir_entry_2 *) buffer)->rec_len)))->inode
2210
2211 /*
2212  * Anybody can rename anything with this: the permission checks are left to the
2213  * higher-level routines.
2214  */
2215 static int ext4_rename (struct inode * old_dir, struct dentry *old_dentry,
2216                            struct inode * new_dir,struct dentry *new_dentry)
2217 {
2218         handle_t *handle;
2219         struct inode * old_inode, * new_inode;
2220         struct buffer_head * old_bh, * new_bh, * dir_bh;
2221         struct ext4_dir_entry_2 * old_de, * new_de;
2222         int retval;
2223
2224         old_bh = new_bh = dir_bh = NULL;
2225
2226         /* Initialize quotas before so that eventual writes go
2227          * in separate transaction */
2228         if (new_dentry->d_inode)
2229                 DQUOT_INIT(new_dentry->d_inode);
2230         handle = ext4_journal_start(old_dir, 2 *
2231                                         EXT4_DATA_TRANS_BLOCKS(old_dir->i_sb) +
2232                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
2233         if (IS_ERR(handle))
2234                 return PTR_ERR(handle);
2235
2236         if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
2237                 handle->h_sync = 1;
2238
2239         old_bh = ext4_find_entry (old_dentry, &old_de);
2240         /*
2241          *  Check for inode number is _not_ due to possible IO errors.
2242          *  We might rmdir the source, keep it as pwd of some process
2243          *  and merrily kill the link to whatever was created under the
2244          *  same name. Goodbye sticky bit ;-<
2245          */
2246         old_inode = old_dentry->d_inode;
2247         retval = -ENOENT;
2248         if (!old_bh || le32_to_cpu(old_de->inode) != old_inode->i_ino)
2249                 goto end_rename;
2250
2251         new_inode = new_dentry->d_inode;
2252         new_bh = ext4_find_entry (new_dentry, &new_de);
2253         if (new_bh) {
2254                 if (!new_inode) {
2255                         brelse (new_bh);
2256                         new_bh = NULL;
2257                 }
2258         }
2259         if (S_ISDIR(old_inode->i_mode)) {
2260                 if (new_inode) {
2261                         retval = -ENOTEMPTY;
2262                         if (!empty_dir (new_inode))
2263                                 goto end_rename;
2264                 }
2265                 retval = -EIO;
2266                 dir_bh = ext4_bread (handle, old_inode, 0, 0, &retval);
2267                 if (!dir_bh)
2268                         goto end_rename;
2269                 if (le32_to_cpu(PARENT_INO(dir_bh->b_data)) != old_dir->i_ino)
2270                         goto end_rename;
2271                 retval = -EMLINK;
2272                 if (!new_inode && new_dir!=old_dir &&
2273                                 new_dir->i_nlink >= EXT4_LINK_MAX)
2274                         goto end_rename;
2275         }
2276         if (!new_bh) {
2277                 retval = ext4_add_entry (handle, new_dentry, old_inode);
2278                 if (retval)
2279                         goto end_rename;
2280         } else {
2281                 BUFFER_TRACE(new_bh, "get write access");
2282                 ext4_journal_get_write_access(handle, new_bh);
2283                 new_de->inode = cpu_to_le32(old_inode->i_ino);
2284                 if (EXT4_HAS_INCOMPAT_FEATURE(new_dir->i_sb,
2285                                               EXT4_FEATURE_INCOMPAT_FILETYPE))
2286                         new_de->file_type = old_de->file_type;
2287                 new_dir->i_version++;
2288                 BUFFER_TRACE(new_bh, "call ext4_journal_dirty_metadata");
2289                 ext4_journal_dirty_metadata(handle, new_bh);
2290                 brelse(new_bh);
2291                 new_bh = NULL;
2292         }
2293
2294         /*
2295          * Like most other Unix systems, set the ctime for inodes on a
2296          * rename.
2297          */
2298         old_inode->i_ctime = CURRENT_TIME_SEC;
2299         ext4_mark_inode_dirty(handle, old_inode);
2300
2301         /*
2302          * ok, that's it
2303          */
2304         if (le32_to_cpu(old_de->inode) != old_inode->i_ino ||
2305             old_de->name_len != old_dentry->d_name.len ||
2306             strncmp(old_de->name, old_dentry->d_name.name, old_de->name_len) ||
2307             (retval = ext4_delete_entry(handle, old_dir,
2308                                         old_de, old_bh)) == -ENOENT) {
2309                 /* old_de could have moved from under us during htree split, so
2310                  * make sure that we are deleting the right entry.  We might
2311                  * also be pointing to a stale entry in the unused part of
2312                  * old_bh so just checking inum and the name isn't enough. */
2313                 struct buffer_head *old_bh2;
2314                 struct ext4_dir_entry_2 *old_de2;
2315
2316                 old_bh2 = ext4_find_entry(old_dentry, &old_de2);
2317                 if (old_bh2) {
2318                         retval = ext4_delete_entry(handle, old_dir,
2319                                                    old_de2, old_bh2);
2320                         brelse(old_bh2);
2321                 }
2322         }
2323         if (retval) {
2324                 ext4_warning(old_dir->i_sb, "ext4_rename",
2325                                 "Deleting old file (%lu), %d, error=%d",
2326                                 old_dir->i_ino, old_dir->i_nlink, retval);
2327         }
2328
2329         if (new_inode) {
2330                 drop_nlink(new_inode);
2331                 new_inode->i_ctime = CURRENT_TIME_SEC;
2332         }
2333         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
2334         ext4_update_dx_flag(old_dir);
2335         if (dir_bh) {
2336                 BUFFER_TRACE(dir_bh, "get_write_access");
2337                 ext4_journal_get_write_access(handle, dir_bh);
2338                 PARENT_INO(dir_bh->b_data) = cpu_to_le32(new_dir->i_ino);
2339                 BUFFER_TRACE(dir_bh, "call ext4_journal_dirty_metadata");
2340                 ext4_journal_dirty_metadata(handle, dir_bh);
2341                 drop_nlink(old_dir);
2342                 if (new_inode) {
2343                         drop_nlink(new_inode);
2344                 } else {
2345                         inc_nlink(new_dir);
2346                         ext4_update_dx_flag(new_dir);
2347                         ext4_mark_inode_dirty(handle, new_dir);
2348                 }
2349         }
2350         ext4_mark_inode_dirty(handle, old_dir);
2351         if (new_inode) {
2352                 ext4_mark_inode_dirty(handle, new_inode);
2353                 if (!new_inode->i_nlink)
2354                         ext4_orphan_add(handle, new_inode);
2355         }
2356         retval = 0;
2357
2358 end_rename:
2359         brelse (dir_bh);
2360         brelse (old_bh);
2361         brelse (new_bh);
2362         ext4_journal_stop(handle);
2363         return retval;
2364 }
2365
2366 /*
2367  * directories can handle most operations...
2368  */
2369 const struct inode_operations ext4_dir_inode_operations = {
2370         .create         = ext4_create,
2371         .lookup         = ext4_lookup,
2372         .link           = ext4_link,
2373         .unlink         = ext4_unlink,
2374         .symlink        = ext4_symlink,
2375         .mkdir          = ext4_mkdir,
2376         .rmdir          = ext4_rmdir,
2377         .mknod          = ext4_mknod,
2378         .rename         = ext4_rename,
2379         .setattr        = ext4_setattr,
2380 #ifdef CONFIG_EXT4DEV_FS_XATTR
2381         .setxattr       = generic_setxattr,
2382         .getxattr       = generic_getxattr,
2383         .listxattr      = ext4_listxattr,
2384         .removexattr    = generic_removexattr,
2385 #endif
2386         .permission     = ext4_permission,
2387 };
2388
2389 const struct inode_operations ext4_special_inode_operations = {
2390         .setattr        = ext4_setattr,
2391 #ifdef CONFIG_EXT4DEV_FS_XATTR
2392         .setxattr       = generic_setxattr,
2393         .getxattr       = generic_getxattr,
2394         .listxattr      = ext4_listxattr,
2395         .removexattr    = generic_removexattr,
2396 #endif
2397         .permission     = ext4_permission,
2398 };