fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
   5  *
   6  * Fix by Harrison Xing <[email protected]>.
   7  * Ext4 code with a lot of help from Eric Jarman <[email protected]>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <[email protected]>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <[email protected]>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <[email protected]> aka bzzz
  13  *  and Andreas Gruenbacher <[email protected]>.
  14  */
  15
  16 /*
  17  * Extended attributes are stored directly in inodes (on file systems with
  18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19  * field contains the block number if an inode uses an additional block. All
  20  * attributes must fit in the inode and one additional block. Blocks that
  21  * contain the identical set of attributes may be shared among several inodes.
  22  * Identical blocks are detected by keeping a cache of blocks that have
  23  * recently been accessed.
  24  *
  25  * The attributes in inodes and on blocks have a different header; the entries
  26  * are stored in the same format:
  27  *
  28  *   +------------------+
  29  *   | header           |
  30  *   | entry 1          | |
  31  *   | entry 2          | | growing downwards
  32  *   | entry 3          | v
  33  *   | four null bytes  |
  34  *   | . . .            |
  35  *   | value 1          | ^
  36  *   | value 3          | | growing upwards
  37  *   | value 2          | |
  38  *   +------------------+
  39  *
  40  * The header is followed by multiple entry descriptors. In disk blocks, the
  41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42  * attribute values are aligned to the end of the block in no specific order.
  43  *
  44  * Locking strategy
  45  * ----------------
  46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47  * EA blocks are only changed if they are exclusive to an inode, so
  48  * holding xattr_sem also means that nothing but the EA block's reference
  49  * count can change. Multiple writers to the same block are synchronized
  50  * by the buffer lock.
  51  */
  52
  53 #include <linux/init.h>
  54 #include <linux/fs.h>
  55 #include <linux/slab.h>
  56 #include <linux/mbcache.h>
  57 #include <linux/quotaops.h>
  58 #include "ext4_jbd2.h"
  59 #include "ext4.h"
  60 #include "xattr.h"
  61 #include "acl.h"
  62
  63 #ifdef EXT4_XATTR_DEBUG
  64 # define ea_idebug(inode, fmt, ...)                                     \
  65         printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",                    \
  66                inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
  67 # define ea_bdebug(bh, fmt, ...)                                        \
  68         printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",                   \
  69                bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
  70 #else
  71 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  72 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  73 #endif
  74
  75 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
  76 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  77                                                  struct ext4_xattr_header *,
  78                                                  struct mb_cache_entry **);
  79 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  80                               struct ext4_xattr_entry *);
  81 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  82                            size_t buffer_size);
  83
  84 static const struct xattr_handler *ext4_xattr_handler_map[] = {
  85         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  86 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  87         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  88         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  89 #endif
  90         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
  91 #ifdef CONFIG_EXT4_FS_SECURITY
  92         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
  93 #endif
  94 };
  95
  96 const struct xattr_handler *ext4_xattr_handlers[] = {
  97         &ext4_xattr_user_handler,
  98         &ext4_xattr_trusted_handler,
  99 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 100         &posix_acl_access_xattr_handler,
 101         &posix_acl_default_xattr_handler,
 102 #endif
 103 #ifdef CONFIG_EXT4_FS_SECURITY
 104         &ext4_xattr_security_handler,
 105 #endif
 106         NULL
 107 };
 108
 109 #define EXT4_GET_MB_CACHE(inode)        (((struct ext4_sb_info *) \
 110                                 inode->i_sb->s_fs_info)->s_mb_cache)
 111
 112 static __le32 ext4_xattr_block_csum(struct inode *inode,
 113                                     sector_t block_nr,
 114                                     struct ext4_xattr_header *hdr)
 115 {
 116         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 117         __u32 csum;
 118         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 119         __u32 dummy_csum = 0;
 120         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 121
 122         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 123                            sizeof(dsk_block_nr));
 124         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 125         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 126         offset += sizeof(dummy_csum);
 127         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 128                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 129
 130         return cpu_to_le32(csum);
 131 }
 132
 133 static int ext4_xattr_block_csum_verify(struct inode *inode,
 134                                         sector_t block_nr,
 135                                         struct ext4_xattr_header *hdr)
 136 {
 137         if (ext4_has_metadata_csum(inode->i_sb) &&
 138             (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 139                 return 0;
 140         return 1;
 141 }
 142
 143 static void ext4_xattr_block_csum_set(struct inode *inode,
 144                                       sector_t block_nr,
 145                                       struct ext4_xattr_header *hdr)
 146 {
 147         if (!ext4_has_metadata_csum(inode->i_sb))
 148                 return;
 149
 150         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 151 }
 152
 153 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 154                                                 struct inode *inode,
 155                                                 struct buffer_head *bh)
 156 {
 157         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 158         return ext4_handle_dirty_metadata(handle, inode, bh);
 159 }
 160
 161 static inline const struct xattr_handler *
 162 ext4_xattr_handler(int name_index)
 163 {
 164         const struct xattr_handler *handler = NULL;
 165
 166         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 167                 handler = ext4_xattr_handler_map[name_index];
 168         return handler;
 169 }
 170
 171 /*
 172  * Inode operation listxattr()
 173  *
 174  * d_inode(dentry)->i_mutex: don't care
 175  */
 176 ssize_t
 177 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 178 {
 179         return ext4_xattr_list(dentry, buffer, size);
 180 }
 181
 182 static int
 183 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
 184                        void *value_start)
 185 {
 186         struct ext4_xattr_entry *e = entry;
 187
 188         /* Find the end of the names list */
 189         while (!IS_LAST_ENTRY(e)) {
 190                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 191                 if ((void *)next >= end)
 192                         return -EFSCORRUPTED;
 193                 e = next;
 194         }
 195
 196         /* Check the values */
 197         while (!IS_LAST_ENTRY(entry)) {
 198                 if (entry->e_value_block != 0)
 199                         return -EFSCORRUPTED;
 200                 if (entry->e_value_size != 0) {
 201                         u16 offs = le16_to_cpu(entry->e_value_offs);
 202                         u32 size = le32_to_cpu(entry->e_value_size);
 203                         void *value;
 204
 205                         /*
 206                          * The value cannot overlap the names, and the value
 207                          * with padding cannot extend beyond 'end'.  Check both
 208                          * the padded and unpadded sizes, since the size may
 209                          * overflow to 0 when adding padding.
 210                          */
 211                         if (offs > end - value_start)
 212                                 return -EFSCORRUPTED;
 213                         value = value_start + offs;
 214                         if (value < (void *)e + sizeof(u32) ||
 215                             size > end - value ||
 216                             EXT4_XATTR_SIZE(size) > end - value)
 217                                 return -EFSCORRUPTED;
 218                 }
 219                 entry = EXT4_XATTR_NEXT(entry);
 220         }
 221
 222         return 0;
 223 }
 224
 225 static inline int
 226 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 227 {
 228         int error;
 229
 230         if (buffer_verified(bh))
 231                 return 0;
 232
 233         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 234             BHDR(bh)->h_blocks != cpu_to_le32(1))
 235                 return -EFSCORRUPTED;
 236         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 237                 return -EFSBADCRC;
 238         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
 239                                        bh->b_data);
 240         if (!error)
 241                 set_buffer_verified(bh);
 242         return error;
 243 }
 244
 245 static int
 246 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 247                          void *end, const char *function, unsigned int line)
 248 {
 249         int error = -EFSCORRUPTED;
 250
 251         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 252             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 253                 goto errout;
 254         error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
 255 errout:
 256         if (error)
 257                 __ext4_error_inode(inode, function, line, 0,
 258                                    "corrupted in-inode xattr");
 259         return error;
 260 }
 261
 262 #define xattr_check_inode(inode, header, end) \
 263         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 264
 265 static inline int
 266 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 267 {
 268         size_t value_size = le32_to_cpu(entry->e_value_size);
 269
 270         if (entry->e_value_block != 0 || value_size > size ||
 271             le16_to_cpu(entry->e_value_offs) + value_size > size)
 272                 return -EFSCORRUPTED;
 273         return 0;
 274 }
 275
 276 static int
 277 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 278                       const char *name, size_t size, int sorted)
 279 {
 280         struct ext4_xattr_entry *entry;
 281         size_t name_len;
 282         int cmp = 1;
 283
 284         if (name == NULL)
 285                 return -EINVAL;
 286         name_len = strlen(name);
 287         entry = *pentry;
 288         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 289                 cmp = name_index - entry->e_name_index;
 290                 if (!cmp)
 291                         cmp = name_len - entry->e_name_len;
 292                 if (!cmp)
 293                         cmp = memcmp(name, entry->e_name, name_len);
 294                 if (cmp <= 0 && (sorted || cmp == 0))
 295                         break;
 296         }
 297         *pentry = entry;
 298         if (!cmp && ext4_xattr_check_entry(entry, size))
 299                 return -EFSCORRUPTED;
 300         return cmp ? -ENODATA : 0;
 301 }
 302
 303 static int
 304 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 305                      void *buffer, size_t buffer_size)
 306 {
 307         struct buffer_head *bh = NULL;
 308         struct ext4_xattr_entry *entry;
 309         size_t size;
 310         int error;
 311         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 312
 313         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 314                   name_index, name, buffer, (long)buffer_size);
 315
 316         error = -ENODATA;
 317         if (!EXT4_I(inode)->i_file_acl)
 318                 goto cleanup;
 319         ea_idebug(inode, "reading block %llu",
 320                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 321         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 322         if (!bh)
 323                 goto cleanup;
 324         ea_bdebug(bh, "b_count=%d, refcount=%d",
 325                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 326         if (ext4_xattr_check_block(inode, bh)) {
 327 bad_block:
 328                 EXT4_ERROR_INODE(inode, "bad block %llu",
 329                                  EXT4_I(inode)->i_file_acl);
 330                 error = -EFSCORRUPTED;
 331                 goto cleanup;
 332         }
 333         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 334         entry = BFIRST(bh);
 335         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 336         if (error == -EFSCORRUPTED)
 337                 goto bad_block;
 338         if (error)
 339                 goto cleanup;
 340         size = le32_to_cpu(entry->e_value_size);
 341         if (buffer) {
 342                 error = -ERANGE;
 343                 if (size > buffer_size)
 344                         goto cleanup;
 345                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 346                        size);
 347         }
 348         error = size;
 349
 350 cleanup:
 351         brelse(bh);
 352         return error;
 353 }
 354
 355 int
 356 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 357                      void *buffer, size_t buffer_size)
 358 {
 359         struct ext4_xattr_ibody_header *header;
 360         struct ext4_xattr_entry *entry;
 361         struct ext4_inode *raw_inode;
 362         struct ext4_iloc iloc;
 363         size_t size;
 364         void *end;
 365         int error;
 366
 367         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 368                 return -ENODATA;
 369         error = ext4_get_inode_loc(inode, &iloc);
 370         if (error)
 371                 return error;
 372         raw_inode = ext4_raw_inode(&iloc);
 373         header = IHDR(inode, raw_inode);
 374         entry = IFIRST(header);
 375         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 376         error = xattr_check_inode(inode, header, end);
 377         if (error)
 378                 goto cleanup;
 379         error = ext4_xattr_find_entry(&entry, name_index, name,
 380                                       end - (void *)entry, 0);
 381         if (error)
 382                 goto cleanup;
 383         size = le32_to_cpu(entry->e_value_size);
 384         if (buffer) {
 385                 error = -ERANGE;
 386                 if (size > buffer_size)
 387                         goto cleanup;
 388                 memcpy(buffer, (void *)IFIRST(header) +
 389                        le16_to_cpu(entry->e_value_offs), size);
 390         }
 391         error = size;
 392
 393 cleanup:
 394         brelse(iloc.bh);
 395         return error;
 396 }
 397
 398 /*
 399  * ext4_xattr_get()
 400  *
 401  * Copy an extended attribute into the buffer
 402  * provided, or compute the buffer size required.
 403  * Buffer is NULL to compute the size of the buffer required.
 404  *
 405  * Returns a negative error number on failure, or the number of bytes
 406  * used / required on success.
 407  */
 408 int
 409 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 410                void *buffer, size_t buffer_size)
 411 {
 412         int error;
 413
 414         if (strlen(name) > 255)
 415                 return -ERANGE;
 416
 417         down_read(&EXT4_I(inode)->xattr_sem);
 418         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 419                                      buffer_size);
 420         if (error == -ENODATA)
 421                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 422                                              buffer_size);
 423         up_read(&EXT4_I(inode)->xattr_sem);
 424         return error;
 425 }
 426
 427 static int
 428 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 429                         char *buffer, size_t buffer_size)
 430 {
 431         size_t rest = buffer_size;
 432
 433         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 434                 const struct xattr_handler *handler =
 435                         ext4_xattr_handler(entry->e_name_index);
 436
 437                 if (handler && (!handler->list || handler->list(dentry))) {
 438                         const char *prefix = handler->prefix ?: handler->name;
 439                         size_t prefix_len = strlen(prefix);
 440                         size_t size = prefix_len + entry->e_name_len + 1;
 441
 442                         if (buffer) {
 443                                 if (size > rest)
 444                                         return -ERANGE;
 445                                 memcpy(buffer, prefix, prefix_len);
 446                                 buffer += prefix_len;
 447                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 448                                 buffer += entry->e_name_len;
 449                                 *buffer++ = 0;
 450                         }
 451                         rest -= size;
 452                 }
 453         }
 454         return buffer_size - rest;  /* total size */
 455 }
 456
 457 static int
 458 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 459 {
 460         struct inode *inode = d_inode(dentry);
 461         struct buffer_head *bh = NULL;
 462         int error;
 463         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 464
 465         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 466                   buffer, (long)buffer_size);
 467
 468         error = 0;
 469         if (!EXT4_I(inode)->i_file_acl)
 470                 goto cleanup;
 471         ea_idebug(inode, "reading block %llu",
 472                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 473         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 474         error = -EIO;
 475         if (!bh)
 476                 goto cleanup;
 477         ea_bdebug(bh, "b_count=%d, refcount=%d",
 478                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 479         if (ext4_xattr_check_block(inode, bh)) {
 480                 EXT4_ERROR_INODE(inode, "bad block %llu",
 481                                  EXT4_I(inode)->i_file_acl);
 482                 error = -EFSCORRUPTED;
 483                 goto cleanup;
 484         }
 485         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 486         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 487
 488 cleanup:
 489         brelse(bh);
 490
 491         return error;
 492 }
 493
 494 static int
 495 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 496 {
 497         struct inode *inode = d_inode(dentry);
 498         struct ext4_xattr_ibody_header *header;
 499         struct ext4_inode *raw_inode;
 500         struct ext4_iloc iloc;
 501         void *end;
 502         int error;
 503
 504         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 505                 return 0;
 506         error = ext4_get_inode_loc(inode, &iloc);
 507         if (error)
 508                 return error;
 509         raw_inode = ext4_raw_inode(&iloc);
 510         header = IHDR(inode, raw_inode);
 511         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 512         error = xattr_check_inode(inode, header, end);
 513         if (error)
 514                 goto cleanup;
 515         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 516                                         buffer, buffer_size);
 517
 518 cleanup:
 519         brelse(iloc.bh);
 520         return error;
 521 }
 522
 523 /*
 524  * ext4_xattr_list()
 525  *
 526  * Copy a list of attribute names into the buffer
 527  * provided, or compute the buffer size required.
 528  * Buffer is NULL to compute the size of the buffer required.
 529  *
 530  * Returns a negative error number on failure, or the number of bytes
 531  * used / required on success.
 532  */
 533 static int
 534 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 535 {
 536         int ret, ret2;
 537
 538         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 539         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 540         if (ret < 0)
 541                 goto errout;
 542         if (buffer) {
 543                 buffer += ret;
 544                 buffer_size -= ret;
 545         }
 546         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 547         if (ret < 0)
 548                 goto errout;
 549         ret += ret2;
 550 errout:
 551         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 552         return ret;
 553 }
 554
 555 /*
 556  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 557  * not set, set it.
 558  */
 559 static void ext4_xattr_update_super_block(handle_t *handle,
 560                                           struct super_block *sb)
 561 {
 562         if (ext4_has_feature_xattr(sb))
 563                 return;
 564
 565         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 566         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 567                 ext4_set_feature_xattr(sb);
 568                 ext4_handle_dirty_super(handle, sb);
 569         }
 570 }
 571
 572 /*
 573  * Release the xattr block BH: If the reference count is > 1, decrement it;
 574  * otherwise free the block.
 575  */
 576 static void
 577 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 578                          struct buffer_head *bh)
 579 {
 580         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 581         u32 hash, ref;
 582         int error = 0;
 583
 584         BUFFER_TRACE(bh, "get_write_access");
 585         error = ext4_journal_get_write_access(handle, bh);
 586         if (error)
 587                 goto out;
 588
 589         lock_buffer(bh);
 590         hash = le32_to_cpu(BHDR(bh)->h_hash);
 591         ref = le32_to_cpu(BHDR(bh)->h_refcount);
 592         if (ref == 1) {
 593                 ea_bdebug(bh, "refcount now=0; freeing");
 594                 /*
 595                  * This must happen under buffer lock for
 596                  * ext4_xattr_block_set() to reliably detect freed block
 597                  */
 598                 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
 599                 get_bh(bh);
 600                 unlock_buffer(bh);
 601                 ext4_free_blocks(handle, inode, bh, 0, 1,
 602                                  EXT4_FREE_BLOCKS_METADATA |
 603                                  EXT4_FREE_BLOCKS_FORGET);
 604         } else {
 605                 ref--;
 606                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
 607                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
 608                         struct mb_cache_entry *ce;
 609
 610                         ce = mb_cache_entry_get(ext4_mb_cache, hash,
 611                                                 bh->b_blocknr);
 612                         if (ce) {
 613                                 ce->e_reusable = 1;
 614                                 mb_cache_entry_put(ext4_mb_cache, ce);
 615                         }
 616                 }
 617
 618                 /*
 619                  * Beware of this ugliness: Releasing of xattr block references
 620                  * from different inodes can race and so we have to protect
 621                  * from a race where someone else frees the block (and releases
 622                  * its journal_head) before we are done dirtying the buffer. In
 623                  * nojournal mode this race is harmless and we actually cannot
 624                  * call ext4_handle_dirty_xattr_block() with locked buffer as
 625                  * that function can call sync_dirty_buffer() so for that case
 626                  * we handle the dirtying after unlocking the buffer.
 627                  */
 628                 if (ext4_handle_valid(handle))
 629                         error = ext4_handle_dirty_xattr_block(handle, inode,
 630                                                               bh);
 631                 unlock_buffer(bh);
 632                 if (!ext4_handle_valid(handle))
 633                         error = ext4_handle_dirty_xattr_block(handle, inode,
 634                                                               bh);
 635                 if (IS_SYNC(inode))
 636                         ext4_handle_sync(handle);
 637                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 638                 ea_bdebug(bh, "refcount now=%d; releasing",
 639                           le32_to_cpu(BHDR(bh)->h_refcount));
 640         }
 641 out:
 642         ext4_std_error(inode->i_sb, error);
 643         return;
 644 }
 645
 646 /*
 647  * Find the available free space for EAs. This also returns the total number of
 648  * bytes used by EA entries.
 649  */
 650 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 651                                     size_t *min_offs, void *base, int *total)
 652 {
 653         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 654                 if (last->e_value_size) {
 655                         size_t offs = le16_to_cpu(last->e_value_offs);
 656                         if (offs < *min_offs)
 657                                 *min_offs = offs;
 658                 }
 659                 if (total)
 660                         *total += EXT4_XATTR_LEN(last->e_name_len);
 661         }
 662         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 663 }
 664
 665 static int
 666 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 667 {
 668         struct ext4_xattr_entry *last;
 669         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 670
 671         /* Compute min_offs and last. */
 672         last = s->first;
 673         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 674                 if (last->e_value_size) {
 675                         size_t offs = le16_to_cpu(last->e_value_offs);
 676                         if (offs < min_offs)
 677                                 min_offs = offs;
 678                 }
 679         }
 680         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 681         if (!s->not_found) {
 682                 if (s->here->e_value_size) {
 683                         size_t size = le32_to_cpu(s->here->e_value_size);
 684                         free += EXT4_XATTR_SIZE(size);
 685                 }
 686                 free += EXT4_XATTR_LEN(name_len);
 687         }
 688         if (i->value) {
 689                 if (free < EXT4_XATTR_LEN(name_len) +
 690                            EXT4_XATTR_SIZE(i->value_len))
 691                         return -ENOSPC;
 692         }
 693
 694         if (i->value && s->not_found) {
 695                 /* Insert the new name. */
 696                 size_t size = EXT4_XATTR_LEN(name_len);
 697                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 698                 memmove((void *)s->here + size, s->here, rest);
 699                 memset(s->here, 0, size);
 700                 s->here->e_name_index = i->name_index;
 701                 s->here->e_name_len = name_len;
 702                 memcpy(s->here->e_name, i->name, name_len);
 703         } else {
 704                 if (s->here->e_value_size) {
 705                         void *first_val = s->base + min_offs;
 706                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 707                         void *val = s->base + offs;
 708                         size_t size = EXT4_XATTR_SIZE(
 709                                 le32_to_cpu(s->here->e_value_size));
 710
 711                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 712                                 /* The old and the new value have the same
 713                                    size. Just replace. */
 714                                 s->here->e_value_size =
 715                                         cpu_to_le32(i->value_len);
 716                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 717                                         memset(val, 0, size);
 718                                 } else {
 719                                         /* Clear pad bytes first. */
 720                                         memset(val + size - EXT4_XATTR_PAD, 0,
 721                                                EXT4_XATTR_PAD);
 722                                         memcpy(val, i->value, i->value_len);
 723                                 }
 724                                 return 0;
 725                         }
 726
 727                         /* Remove the old value. */
 728                         memmove(first_val + size, first_val, val - first_val);
 729                         memset(first_val, 0, size);
 730                         s->here->e_value_size = 0;
 731                         s->here->e_value_offs = 0;
 732                         min_offs += size;
 733
 734                         /* Adjust all value offsets. */
 735                         last = s->first;
 736                         while (!IS_LAST_ENTRY(last)) {
 737                                 size_t o = le16_to_cpu(last->e_value_offs);
 738                                 if (last->e_value_size && o < offs)
 739                                         last->e_value_offs =
 740                                                 cpu_to_le16(o + size);
 741                                 last = EXT4_XATTR_NEXT(last);
 742                         }
 743                 }
 744                 if (!i->value) {
 745                         /* Remove the old name. */
 746                         size_t size = EXT4_XATTR_LEN(name_len);
 747                         last = ENTRY((void *)last - size);
 748                         memmove(s->here, (void *)s->here + size,
 749                                 (void *)last - (void *)s->here + sizeof(__u32));
 750                         memset(last, 0, size);
 751                 }
 752         }
 753
 754         if (i->value) {
 755                 /* Insert the new value. */
 756                 s->here->e_value_size = cpu_to_le32(i->value_len);
 757                 if (i->value_len) {
 758                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 759                         void *val = s->base + min_offs - size;
 760                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 761                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 762                                 memset(val, 0, size);
 763                         } else {
 764                                 /* Clear the pad bytes first. */
 765                                 memset(val + size - EXT4_XATTR_PAD, 0,
 766                                        EXT4_XATTR_PAD);
 767                                 memcpy(val, i->value, i->value_len);
 768                         }
 769                 }
 770         }
 771         return 0;
 772 }
 773
 774 struct ext4_xattr_block_find {
 775         struct ext4_xattr_search s;
 776         struct buffer_head *bh;
 777 };
 778
 779 static int
 780 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 781                       struct ext4_xattr_block_find *bs)
 782 {
 783         struct super_block *sb = inode->i_sb;
 784         int error;
 785
 786         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 787                   i->name_index, i->name, i->value, (long)i->value_len);
 788
 789         if (EXT4_I(inode)->i_file_acl) {
 790                 /* The inode already has an extended attribute block. */
 791                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 792                 error = -EIO;
 793                 if (!bs->bh)
 794                         goto cleanup;
 795                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 796                         atomic_read(&(bs->bh->b_count)),
 797                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 798                 if (ext4_xattr_check_block(inode, bs->bh)) {
 799                         EXT4_ERROR_INODE(inode, "bad block %llu",
 800                                          EXT4_I(inode)->i_file_acl);
 801                         error = -EFSCORRUPTED;
 802                         goto cleanup;
 803                 }
 804                 /* Find the named attribute. */
 805                 bs->s.base = BHDR(bs->bh);
 806                 bs->s.first = BFIRST(bs->bh);
 807                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 808                 bs->s.here = bs->s.first;
 809                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 810                                               i->name, bs->bh->b_size, 1);
 811                 if (error && error != -ENODATA)
 812                         goto cleanup;
 813                 bs->s.not_found = error;
 814         }
 815         error = 0;
 816
 817 cleanup:
 818         return error;
 819 }
 820
 821 static int
 822 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 823                      struct ext4_xattr_info *i,
 824                      struct ext4_xattr_block_find *bs)
 825 {
 826         struct super_block *sb = inode->i_sb;
 827         struct buffer_head *new_bh = NULL;
 828         struct ext4_xattr_search *s = &bs->s;
 829         struct mb_cache_entry *ce = NULL;
 830         int error = 0;
 831         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 832
 833 #define header(x) ((struct ext4_xattr_header *)(x))
 834
 835         if (i->value && i->value_len > sb->s_blocksize)
 836                 return -ENOSPC;
 837         if (s->base) {
 838                 BUFFER_TRACE(bs->bh, "get_write_access");
 839                 error = ext4_journal_get_write_access(handle, bs->bh);
 840                 if (error)
 841                         goto cleanup;
 842                 lock_buffer(bs->bh);
 843
 844                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 845                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
 846
 847                         /*
 848                          * This must happen under buffer lock for
 849                          * ext4_xattr_block_set() to reliably detect modified
 850                          * block
 851                          */
 852                         mb_cache_entry_delete_block(ext4_mb_cache, hash,
 853                                                     bs->bh->b_blocknr);
 854                         ea_bdebug(bs->bh, "modifying in-place");
 855                         error = ext4_xattr_set_entry(i, s);
 856                         if (!error) {
 857                                 if (!IS_LAST_ENTRY(s->first))
 858                                         ext4_xattr_rehash(header(s->base),
 859                                                           s->here);
 860                                 ext4_xattr_cache_insert(ext4_mb_cache,
 861                                         bs->bh);
 862                         }
 863                         unlock_buffer(bs->bh);
 864                         if (error == -EFSCORRUPTED)
 865                                 goto bad_block;
 866                         if (!error)
 867                                 error = ext4_handle_dirty_xattr_block(handle,
 868                                                                       inode,
 869                                                                       bs->bh);
 870                         if (error)
 871                                 goto cleanup;
 872                         goto inserted;
 873                 } else {
 874                         int offset = (char *)s->here - bs->bh->b_data;
 875
 876                         unlock_buffer(bs->bh);
 877                         ea_bdebug(bs->bh, "cloning");
 878                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 879                         error = -ENOMEM;
 880                         if (s->base == NULL)
 881                                 goto cleanup;
 882                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 883                         s->first = ENTRY(header(s->base)+1);
 884                         header(s->base)->h_refcount = cpu_to_le32(1);
 885                         s->here = ENTRY(s->base + offset);
 886                         s->end = s->base + bs->bh->b_size;
 887                 }
 888         } else {
 889                 /* Allocate a buffer where we construct the new block. */
 890                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 891                 /* assert(header == s->base) */
 892                 error = -ENOMEM;
 893                 if (s->base == NULL)
 894                         goto cleanup;
 895                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 896                 header(s->base)->h_blocks = cpu_to_le32(1);
 897                 header(s->base)->h_refcount = cpu_to_le32(1);
 898                 s->first = ENTRY(header(s->base)+1);
 899                 s->here = ENTRY(header(s->base)+1);
 900                 s->end = s->base + sb->s_blocksize;
 901         }
 902
 903         error = ext4_xattr_set_entry(i, s);
 904         if (error == -EFSCORRUPTED)
 905                 goto bad_block;
 906         if (error)
 907                 goto cleanup;
 908         if (!IS_LAST_ENTRY(s->first))
 909                 ext4_xattr_rehash(header(s->base), s->here);
 910
 911 inserted:
 912         if (!IS_LAST_ENTRY(s->first)) {
 913                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 914                 if (new_bh) {
 915                         /* We found an identical block in the cache. */
 916                         if (new_bh == bs->bh)
 917                                 ea_bdebug(new_bh, "keeping");
 918                         else {
 919                                 u32 ref;
 920
 921                                 /* The old block is released after updating
 922                                    the inode. */
 923                                 error = dquot_alloc_block(inode,
 924                                                 EXT4_C2B(EXT4_SB(sb), 1));
 925                                 if (error)
 926                                         goto cleanup;
 927                                 BUFFER_TRACE(new_bh, "get_write_access");
 928                                 error = ext4_journal_get_write_access(handle,
 929                                                                       new_bh);
 930                                 if (error)
 931                                         goto cleanup_dquot;
 932                                 lock_buffer(new_bh);
 933                                 /*
 934                                  * We have to be careful about races with
 935                                  * freeing, rehashing or adding references to
 936                                  * xattr block. Once we hold buffer lock xattr
 937                                  * block's state is stable so we can check
 938                                  * whether the block got freed / rehashed or
 939                                  * not.  Since we unhash mbcache entry under
 940                                  * buffer lock when freeing / rehashing xattr
 941                                  * block, checking whether entry is still
 942                                  * hashed is reliable. Same rules hold for
 943                                  * e_reusable handling.
 944                                  */
 945                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
 946                                     !ce->e_reusable) {
 947                                         /*
 948                                          * Undo everything and check mbcache
 949                                          * again.
 950                                          */
 951                                         unlock_buffer(new_bh);
 952                                         dquot_free_block(inode,
 953                                                          EXT4_C2B(EXT4_SB(sb),
 954                                                                   1));
 955                                         brelse(new_bh);
 956                                         mb_cache_entry_put(ext4_mb_cache, ce);
 957                                         ce = NULL;
 958                                         new_bh = NULL;
 959                                         goto inserted;
 960                                 }
 961                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
 962                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
 963                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
 964                                         ce->e_reusable = 0;
 965                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 966                                           ref);
 967                                 unlock_buffer(new_bh);
 968                                 error = ext4_handle_dirty_xattr_block(handle,
 969                                                                       inode,
 970                                                                       new_bh);
 971                                 if (error)
 972                                         goto cleanup_dquot;
 973                         }
 974                         mb_cache_entry_touch(ext4_mb_cache, ce);
 975                         mb_cache_entry_put(ext4_mb_cache, ce);
 976                         ce = NULL;
 977                 } else if (bs->bh && s->base == bs->bh->b_data) {
 978                         /* We were modifying this block in-place. */
 979                         ea_bdebug(bs->bh, "keeping this block");
 980                         new_bh = bs->bh;
 981                         get_bh(new_bh);
 982                 } else {
 983                         /* We need to allocate a new block */
 984                         ext4_fsblk_t goal, block;
 985
 986                         goal = ext4_group_first_block_no(sb,
 987                                                 EXT4_I(inode)->i_block_group);
 988
 989                         /* non-extent files can't have physical blocks past 2^32 */
 990                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 991                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 992
 993                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 994                                                      NULL, &error);
 995                         if (error)
 996                                 goto cleanup;
 997
 998                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 999                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
1000
1001                         ea_idebug(inode, "creating block %llu",
1002                                   (unsigned long long)block);
1003
1004                         new_bh = sb_getblk(sb, block);
1005                         if (unlikely(!new_bh)) {
1006                                 error = -ENOMEM;
1007 getblk_failed:
1008                                 ext4_free_blocks(handle, inode, NULL, block, 1,
1009                                                  EXT4_FREE_BLOCKS_METADATA);
1010                                 goto cleanup;
1011                         }
1012                         lock_buffer(new_bh);
1013                         error = ext4_journal_get_create_access(handle, new_bh);
1014                         if (error) {
1015                                 unlock_buffer(new_bh);
1016                                 error = -EIO;
1017                                 goto getblk_failed;
1018                         }
1019                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
1020                         set_buffer_uptodate(new_bh);
1021                         unlock_buffer(new_bh);
1022                         ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1023                         error = ext4_handle_dirty_xattr_block(handle,
1024                                                               inode, new_bh);
1025                         if (error)
1026                                 goto cleanup;
1027                 }
1028         }
1029
1030         /* Update the inode. */
1031         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1032
1033         /* Drop the previous xattr block. */
1034         if (bs->bh && bs->bh != new_bh)
1035                 ext4_xattr_release_block(handle, inode, bs->bh);
1036         error = 0;
1037
1038 cleanup:
1039         if (ce)
1040                 mb_cache_entry_put(ext4_mb_cache, ce);
1041         brelse(new_bh);
1042         if (!(bs->bh && s->base == bs->bh->b_data))
1043                 kfree(s->base);
1044
1045         return error;
1046
1047 cleanup_dquot:
1048         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1049         goto cleanup;
1050
1051 bad_block:
1052         EXT4_ERROR_INODE(inode, "bad block %llu",
1053                          EXT4_I(inode)->i_file_acl);
1054         goto cleanup;
1055
1056 #undef header
1057 }
1058
1059 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1060                           struct ext4_xattr_ibody_find *is)
1061 {
1062         struct ext4_xattr_ibody_header *header;
1063         struct ext4_inode *raw_inode;
1064         int error;
1065
1066         if (EXT4_I(inode)->i_extra_isize == 0)
1067                 return 0;
1068         raw_inode = ext4_raw_inode(&is->iloc);
1069         header = IHDR(inode, raw_inode);
1070         is->s.base = is->s.first = IFIRST(header);
1071         is->s.here = is->s.first;
1072         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1073         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1074                 error = xattr_check_inode(inode, header, is->s.end);
1075                 if (error)
1076                         return error;
1077                 /* Find the named attribute. */
1078                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1079                                               i->name, is->s.end -
1080                                               (void *)is->s.base, 0);
1081                 if (error && error != -ENODATA)
1082                         return error;
1083                 is->s.not_found = error;
1084         }
1085         return 0;
1086 }
1087
1088 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1089                                 struct ext4_xattr_info *i,
1090                                 struct ext4_xattr_ibody_find *is)
1091 {
1092         struct ext4_xattr_ibody_header *header;
1093         struct ext4_xattr_search *s = &is->s;
1094         int error;
1095
1096         if (EXT4_I(inode)->i_extra_isize == 0)
1097                 return -ENOSPC;
1098         error = ext4_xattr_set_entry(i, s);
1099         if (error) {
1100                 if (error == -ENOSPC &&
1101                     ext4_has_inline_data(inode)) {
1102                         error = ext4_try_to_evict_inline_data(handle, inode,
1103                                         EXT4_XATTR_LEN(strlen(i->name) +
1104                                         EXT4_XATTR_SIZE(i->value_len)));
1105                         if (error)
1106                                 return error;
1107                         error = ext4_xattr_ibody_find(inode, i, is);
1108                         if (error)
1109                                 return error;
1110                         error = ext4_xattr_set_entry(i, s);
1111                 }
1112                 if (error)
1113                         return error;
1114         }
1115         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1116         if (!IS_LAST_ENTRY(s->first)) {
1117                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1118                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1119         } else {
1120                 header->h_magic = cpu_to_le32(0);
1121                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1122         }
1123         return 0;
1124 }
1125
1126 static int ext4_xattr_ibody_set(struct inode *inode,
1127                                 struct ext4_xattr_info *i,
1128                                 struct ext4_xattr_ibody_find *is)
1129 {
1130         struct ext4_xattr_ibody_header *header;
1131         struct ext4_xattr_search *s = &is->s;
1132         int error;
1133
1134         if (EXT4_I(inode)->i_extra_isize == 0)
1135                 return -ENOSPC;
1136         error = ext4_xattr_set_entry(i, s);
1137         if (error)
1138                 return error;
1139         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1140         if (!IS_LAST_ENTRY(s->first)) {
1141                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1142                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1143         } else {
1144                 header->h_magic = cpu_to_le32(0);
1145                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1146         }
1147         return 0;
1148 }
1149
1150 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1151                                  struct ext4_xattr_info *i)
1152 {
1153         void *value;
1154
1155         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1156                 return 0;
1157         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1158         return !memcmp(value, i->value, i->value_len);
1159 }
1160
1161 /*
1162  * ext4_xattr_set_handle()
1163  *
1164  * Create, replace or remove an extended attribute for this inode.  Value
1165  * is NULL to remove an existing extended attribute, and non-NULL to
1166  * either replace an existing extended attribute, or create a new extended
1167  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1168  * specify that an extended attribute must exist and must not exist
1169  * previous to the call, respectively.
1170  *
1171  * Returns 0, or a negative error number on failure.
1172  */
1173 int
1174 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1175                       const char *name, const void *value, size_t value_len,
1176                       int flags)
1177 {
1178         struct ext4_xattr_info i = {
1179                 .name_index = name_index,
1180                 .name = name,
1181                 .value = value,
1182                 .value_len = value_len,
1183
1184         };
1185         struct ext4_xattr_ibody_find is = {
1186                 .s = { .not_found = -ENODATA, },
1187         };
1188         struct ext4_xattr_block_find bs = {
1189                 .s = { .not_found = -ENODATA, },
1190         };
1191         unsigned long no_expand;
1192         int error;
1193
1194         if (!name)
1195                 return -EINVAL;
1196         if (strlen(name) > 255)
1197                 return -ERANGE;
1198         down_write(&EXT4_I(inode)->xattr_sem);
1199         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1200         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1201
1202         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1203         if (error)
1204                 goto cleanup;
1205
1206         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1207                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1208                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1209                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1210         }
1211
1212         error = ext4_xattr_ibody_find(inode, &i, &is);
1213         if (error)
1214                 goto cleanup;
1215         if (is.s.not_found)
1216                 error = ext4_xattr_block_find(inode, &i, &bs);
1217         if (error)
1218                 goto cleanup;
1219         if (is.s.not_found && bs.s.not_found) {
1220                 error = -ENODATA;
1221                 if (flags & XATTR_REPLACE)
1222                         goto cleanup;
1223                 error = 0;
1224                 if (!value)
1225                         goto cleanup;
1226         } else {
1227                 error = -EEXIST;
1228                 if (flags & XATTR_CREATE)
1229                         goto cleanup;
1230         }
1231         if (!value) {
1232                 if (!is.s.not_found)
1233                         error = ext4_xattr_ibody_set(inode, &i, &is);
1234                 else if (!bs.s.not_found)
1235                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1236         } else {
1237                 error = 0;
1238                 /* Xattr value did not change? Save us some work and bail out */
1239                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1240                         goto cleanup;
1241                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1242                         goto cleanup;
1243
1244                 error = ext4_xattr_ibody_set(inode, &i, &is);
1245                 if (!error && !bs.s.not_found) {
1246                         i.value = NULL;
1247                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1248                 } else if (error == -ENOSPC) {
1249                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1250                                 error = ext4_xattr_block_find(inode, &i, &bs);
1251                                 if (error)
1252                                         goto cleanup;
1253                         }
1254                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1255                         if (error)
1256                                 goto cleanup;
1257                         if (!is.s.not_found) {
1258                                 i.value = NULL;
1259                                 error = ext4_xattr_ibody_set(inode, &i, &is);
1260                         }
1261                 }
1262         }
1263         if (!error) {
1264                 ext4_xattr_update_super_block(handle, inode->i_sb);
1265                 inode->i_ctime = current_time(inode);
1266                 if (!value)
1267                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1268                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1269                 /*
1270                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1271                  * error != 0.
1272                  */
1273                 is.iloc.bh = NULL;
1274                 if (IS_SYNC(inode))
1275                         ext4_handle_sync(handle);
1276         }
1277
1278 cleanup:
1279         brelse(is.iloc.bh);
1280         brelse(bs.bh);
1281         if (no_expand == 0)
1282                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1283         up_write(&EXT4_I(inode)->xattr_sem);
1284         return error;
1285 }
1286
1287 /*
1288  * ext4_xattr_set()
1289  *
1290  * Like ext4_xattr_set_handle, but start from an inode. This extended
1291  * attribute modification is a filesystem transaction by itself.
1292  *
1293  * Returns 0, or a negative error number on failure.
1294  */
1295 int
1296 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1297                const void *value, size_t value_len, int flags)
1298 {
1299         handle_t *handle;
1300         int error, retries = 0;
1301         int credits = ext4_jbd2_credits_xattr(inode);
1302
1303 retry:
1304         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1305         if (IS_ERR(handle)) {
1306                 error = PTR_ERR(handle);
1307         } else {
1308                 int error2;
1309
1310                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1311                                               value, value_len, flags);
1312                 error2 = ext4_journal_stop(handle);
1313                 if (error == -ENOSPC &&
1314                     ext4_should_retry_alloc(inode->i_sb, &retries))
1315                         goto retry;
1316                 if (error == 0)
1317                         error = error2;
1318         }
1319
1320         return error;
1321 }
1322
1323 /*
1324  * Shift the EA entries in the inode to create space for the increased
1325  * i_extra_isize.
1326  */
1327 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1328                                      int value_offs_shift, void *to,
1329                                      void *from, size_t n)
1330 {
1331         struct ext4_xattr_entry *last = entry;
1332         int new_offs;
1333
1334         /* We always shift xattr headers further thus offsets get lower */
1335         BUG_ON(value_offs_shift > 0);
1336
1337         /* Adjust the value offsets of the entries */
1338         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1339                 if (last->e_value_size) {
1340                         new_offs = le16_to_cpu(last->e_value_offs) +
1341                                                         value_offs_shift;
1342                         last->e_value_offs = cpu_to_le16(new_offs);
1343                 }
1344         }
1345         /* Shift the entries by n bytes */
1346         memmove(to, from, n);
1347 }
1348
1349 /*
1350  * Move xattr pointed to by 'entry' from inode into external xattr block
1351  */
1352 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
1353                                     struct ext4_inode *raw_inode,
1354                                     struct ext4_xattr_entry *entry)
1355 {
1356         struct ext4_xattr_ibody_find *is = NULL;
1357         struct ext4_xattr_block_find *bs = NULL;
1358         char *buffer = NULL, *b_entry_name = NULL;
1359         size_t value_offs, value_size;
1360         struct ext4_xattr_info i = {
1361                 .value = NULL,
1362                 .value_len = 0,
1363                 .name_index = entry->e_name_index,
1364         };
1365         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1366         int error;
1367
1368         value_offs = le16_to_cpu(entry->e_value_offs);
1369         value_size = le32_to_cpu(entry->e_value_size);
1370
1371         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1372         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1373         buffer = kmalloc(value_size, GFP_NOFS);
1374         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1375         if (!is || !bs || !buffer || !b_entry_name) {
1376                 error = -ENOMEM;
1377                 goto out;
1378         }
1379
1380         is->s.not_found = -ENODATA;
1381         bs->s.not_found = -ENODATA;
1382         is->iloc.bh = NULL;
1383         bs->bh = NULL;
1384
1385         /* Save the entry name and the entry value */
1386         memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
1387         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1388         b_entry_name[entry->e_name_len] = '\0';
1389         i.name = b_entry_name;
1390
1391         error = ext4_get_inode_loc(inode, &is->iloc);
1392         if (error)
1393                 goto out;
1394
1395         error = ext4_xattr_ibody_find(inode, &i, is);
1396         if (error)
1397                 goto out;
1398
1399         /* Remove the chosen entry from the inode */
1400         error = ext4_xattr_ibody_set(inode, &i, is);
1401         if (error)
1402                 goto out;
1403
1404         i.name = b_entry_name;
1405         i.value = buffer;
1406         i.value_len = value_size;
1407         error = ext4_xattr_block_find(inode, &i, bs);
1408         if (error)
1409                 goto out;
1410
1411         /* Add entry which was removed from the inode into the block */
1412         error = ext4_xattr_block_set(handle, inode, &i, bs);
1413         if (error)
1414                 goto out;
1415         error = 0;
1416 out:
1417         kfree(b_entry_name);
1418         kfree(buffer);
1419         if (is)
1420                 brelse(is->iloc.bh);
1421         kfree(is);
1422         kfree(bs);
1423
1424         return error;
1425 }
1426
1427 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
1428                                        struct ext4_inode *raw_inode,
1429                                        int isize_diff, size_t ifree,
1430                                        size_t bfree, int *total_ino)
1431 {
1432         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1433         struct ext4_xattr_entry *small_entry;
1434         struct ext4_xattr_entry *entry;
1435         struct ext4_xattr_entry *last;
1436         unsigned int entry_size;        /* EA entry size */
1437         unsigned int total_size;        /* EA entry size + value size */
1438         unsigned int min_total_size;
1439         int error;
1440
1441         while (isize_diff > ifree) {
1442                 entry = NULL;
1443                 small_entry = NULL;
1444                 min_total_size = ~0U;
1445                 last = IFIRST(header);
1446                 /* Find the entry best suited to be pushed into EA block */
1447                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1448                         total_size =
1449                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1450                                         EXT4_XATTR_LEN(last->e_name_len);
1451                         if (total_size <= bfree &&
1452                             total_size < min_total_size) {
1453                                 if (total_size + ifree < isize_diff) {
1454                                         small_entry = last;
1455                                 } else {
1456                                         entry = last;
1457                                         min_total_size = total_size;
1458                                 }
1459                         }
1460                 }
1461
1462                 if (entry == NULL) {
1463                         if (small_entry == NULL)
1464                                 return -ENOSPC;
1465                         entry = small_entry;
1466                 }
1467
1468                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1469                 total_size = entry_size +
1470                         EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
1471                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
1472                                                  entry);
1473                 if (error)
1474                         return error;
1475
1476                 *total_ino -= entry_size;
1477                 ifree += total_size;
1478                 bfree -= total_size;
1479         }
1480
1481         return 0;
1482 }
1483
1484 /*
1485  * Expand an inode by new_extra_isize bytes when EAs are present.
1486  * Returns 0 on success or negative error number on failure.
1487  */
1488 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1489                                struct ext4_inode *raw_inode, handle_t *handle)
1490 {
1491         struct ext4_xattr_ibody_header *header;
1492         struct buffer_head *bh = NULL;
1493         size_t min_offs;
1494         size_t ifree, bfree;
1495         int total_ino;
1496         void *base, *end;
1497         int error = 0, tried_min_extra_isize = 0;
1498         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1499         int isize_diff; /* How much do we need to grow i_extra_isize */
1500
1501         down_write(&EXT4_I(inode)->xattr_sem);
1502         /*
1503          * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty
1504          */
1505         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1506 retry:
1507         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
1508         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
1509                 goto out;
1510
1511         header = IHDR(inode, raw_inode);
1512
1513         /*
1514          * Check if enough free space is available in the inode to shift the
1515          * entries ahead by new_extra_isize.
1516          */
1517
1518         base = IFIRST(header);
1519         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1520         min_offs = end - base;
1521         total_ino = sizeof(struct ext4_xattr_ibody_header);
1522
1523         error = xattr_check_inode(inode, header, end);
1524         if (error)
1525                 goto cleanup;
1526
1527         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
1528         if (ifree >= isize_diff)
1529                 goto shift;
1530
1531         /*
1532          * Enough free space isn't available in the inode, check if
1533          * EA block can hold new_extra_isize bytes.
1534          */
1535         if (EXT4_I(inode)->i_file_acl) {
1536                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1537                 error = -EIO;
1538                 if (!bh)
1539                         goto cleanup;
1540                 if (ext4_xattr_check_block(inode, bh)) {
1541                         EXT4_ERROR_INODE(inode, "bad block %llu",
1542                                          EXT4_I(inode)->i_file_acl);
1543                         error = -EFSCORRUPTED;
1544                         goto cleanup;
1545                 }
1546                 base = BHDR(bh);
1547                 end = bh->b_data + bh->b_size;
1548                 min_offs = end - base;
1549                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
1550                                               NULL);
1551                 if (bfree + ifree < isize_diff) {
1552                         if (!tried_min_extra_isize && s_min_extra_isize) {
1553                                 tried_min_extra_isize++;
1554                                 new_extra_isize = s_min_extra_isize;
1555                                 brelse(bh);
1556                                 goto retry;
1557                         }
1558                         error = -ENOSPC;
1559                         goto cleanup;
1560                 }
1561         } else {
1562                 bfree = inode->i_sb->s_blocksize;
1563         }
1564
1565         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
1566                                             isize_diff, ifree, bfree,
1567                                             &total_ino);
1568         if (error) {
1569                 if (error == -ENOSPC && !tried_min_extra_isize &&
1570                     s_min_extra_isize) {
1571                         tried_min_extra_isize++;
1572                         new_extra_isize = s_min_extra_isize;
1573                         brelse(bh);
1574                         goto retry;
1575                 }
1576                 goto cleanup;
1577         }
1578 shift:
1579         /* Adjust the offsets and shift the remaining entries ahead */
1580         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
1581                         - new_extra_isize, (void *)raw_inode +
1582                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1583                         (void *)header, total_ino);
1584         EXT4_I(inode)->i_extra_isize = new_extra_isize;
1585         brelse(bh);
1586 out:
1587         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1588         up_write(&EXT4_I(inode)->xattr_sem);
1589         return 0;
1590
1591 cleanup:
1592         brelse(bh);
1593         /*
1594          * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode
1595          * size expansion failed.
1596          */
1597         up_write(&EXT4_I(inode)->xattr_sem);
1598         return error;
1599 }
1600
1601
1602
1603 /*
1604  * ext4_xattr_delete_inode()
1605  *
1606  * Free extended attribute resources associated with this inode. This
1607  * is called immediately before an inode is freed. We have exclusive
1608  * access to the inode.
1609  */
1610 void
1611 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1612 {
1613         struct buffer_head *bh = NULL;
1614
1615         if (!EXT4_I(inode)->i_file_acl)
1616                 goto cleanup;
1617         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1618         if (!bh) {
1619                 EXT4_ERROR_INODE(inode, "block %llu read error",
1620                                  EXT4_I(inode)->i_file_acl);
1621                 goto cleanup;
1622         }
1623         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1624             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1625                 EXT4_ERROR_INODE(inode, "bad block %llu",
1626                                  EXT4_I(inode)->i_file_acl);
1627                 goto cleanup;
1628         }
1629         ext4_xattr_release_block(handle, inode, bh);
1630         EXT4_I(inode)->i_file_acl = 0;
1631
1632 cleanup:
1633         brelse(bh);
1634 }
1635
1636 /*
1637  * ext4_xattr_cache_insert()
1638  *
1639  * Create a new entry in the extended attribute cache, and insert
1640  * it unless such an entry is already in the cache.
1641  *
1642  * Returns 0, or a negative error number on failure.
1643  */
1644 static void
1645 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1646 {
1647         struct ext4_xattr_header *header = BHDR(bh);
1648         __u32 hash = le32_to_cpu(header->h_hash);
1649         int reusable = le32_to_cpu(header->h_refcount) <
1650                        EXT4_XATTR_REFCOUNT_MAX;
1651         int error;
1652
1653         error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1654                                       bh->b_blocknr, reusable);
1655         if (error) {
1656                 if (error == -EBUSY)
1657                         ea_bdebug(bh, "already in cache");
1658         } else
1659                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1660 }
1661
1662 /*
1663  * ext4_xattr_cmp()
1664  *
1665  * Compare two extended attribute blocks for equality.
1666  *
1667  * Returns 0 if the blocks are equal, 1 if they differ, and
1668  * a negative error number on errors.
1669  */
1670 static int
1671 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1672                struct ext4_xattr_header *header2)
1673 {
1674         struct ext4_xattr_entry *entry1, *entry2;
1675
1676         entry1 = ENTRY(header1+1);
1677         entry2 = ENTRY(header2+1);
1678         while (!IS_LAST_ENTRY(entry1)) {
1679                 if (IS_LAST_ENTRY(entry2))
1680                         return 1;
1681                 if (entry1->e_hash != entry2->e_hash ||
1682                     entry1->e_name_index != entry2->e_name_index ||
1683                     entry1->e_name_len != entry2->e_name_len ||
1684                     entry1->e_value_size != entry2->e_value_size ||
1685                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1686                         return 1;
1687                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1688                         return -EFSCORRUPTED;
1689                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1690                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1691                            le32_to_cpu(entry1->e_value_size)))
1692                         return 1;
1693
1694                 entry1 = EXT4_XATTR_NEXT(entry1);
1695                 entry2 = EXT4_XATTR_NEXT(entry2);
1696         }
1697         if (!IS_LAST_ENTRY(entry2))
1698                 return 1;
1699         return 0;
1700 }
1701
1702 /*
1703  * ext4_xattr_cache_find()
1704  *
1705  * Find an identical extended attribute block.
1706  *
1707  * Returns a pointer to the block found, or NULL if such a block was
1708  * not found or an error occurred.
1709  */
1710 static struct buffer_head *
1711 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1712                       struct mb_cache_entry **pce)
1713 {
1714         __u32 hash = le32_to_cpu(header->h_hash);
1715         struct mb_cache_entry *ce;
1716         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1717
1718         if (!header->h_hash)
1719                 return NULL;  /* never share */
1720         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1721         ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1722         while (ce) {
1723                 struct buffer_head *bh;
1724
1725                 bh = sb_bread(inode->i_sb, ce->e_block);
1726                 if (!bh) {
1727                         EXT4_ERROR_INODE(inode, "block %lu read error",
1728                                          (unsigned long) ce->e_block);
1729                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1730                         *pce = ce;
1731                         return bh;
1732                 }
1733                 brelse(bh);
1734                 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1735         }
1736         return NULL;
1737 }
1738
1739 #define NAME_HASH_SHIFT 5
1740 #define VALUE_HASH_SHIFT 16
1741
1742 /*
1743  * ext4_xattr_hash_entry()
1744  *
1745  * Compute the hash of an extended attribute.
1746  */
1747 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1748                                          struct ext4_xattr_entry *entry)
1749 {
1750         __u32 hash = 0;
1751         char *name = entry->e_name;
1752         int n;
1753
1754         for (n = 0; n < entry->e_name_len; n++) {
1755                 hash = (hash << NAME_HASH_SHIFT) ^
1756                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1757                        *name++;
1758         }
1759
1760         if (entry->e_value_size != 0) {
1761                 __le32 *value = (__le32 *)((char *)header +
1762                         le16_to_cpu(entry->e_value_offs));
1763                 for (n = (le32_to_cpu(entry->e_value_size) +
1764                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1765                         hash = (hash << VALUE_HASH_SHIFT) ^
1766                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1767                                le32_to_cpu(*value++);
1768                 }
1769         }
1770         entry->e_hash = cpu_to_le32(hash);
1771 }
1772
1773 #undef NAME_HASH_SHIFT
1774 #undef VALUE_HASH_SHIFT
1775
1776 #define BLOCK_HASH_SHIFT 16
1777
1778 /*
1779  * ext4_xattr_rehash()
1780  *
1781  * Re-compute the extended attribute hash value after an entry has changed.
1782  */
1783 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1784                               struct ext4_xattr_entry *entry)
1785 {
1786         struct ext4_xattr_entry *here;
1787         __u32 hash = 0;
1788
1789         ext4_xattr_hash_entry(header, entry);
1790         here = ENTRY(header+1);
1791         while (!IS_LAST_ENTRY(here)) {
1792                 if (!here->e_hash) {
1793                         /* Block is not shared if an entry's hash value == 0 */
1794                         hash = 0;
1795                         break;
1796                 }
1797                 hash = (hash << BLOCK_HASH_SHIFT) ^
1798                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1799                        le32_to_cpu(here->e_hash);
1800                 here = EXT4_XATTR_NEXT(here);
1801         }
1802         header->h_hash = cpu_to_le32(hash);
1803 }
1804
1805 #undef BLOCK_HASH_SHIFT
1806
1807 #define HASH_BUCKET_BITS        10
1808
1809 struct mb_cache *
1810 ext4_xattr_create_cache(void)
1811 {
1812         return mb_cache_create(HASH_BUCKET_BITS);
1813 }
1814
1815 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1816 {
1817         if (cache)
1818                 mb_cache_destroy(cache);
1819 }
1820