fs/ext4/xattr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/fs/ext4/xattr.c
   4  *
   5  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   6  *
   7  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   8  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   9  * Extended attributes for symlinks and special files added per
  10  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  11  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  12  *  Red Hat Inc.
  13  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  14  *  and Andreas Gruenbacher <agruen@suse.de>.
  15  */
  16
  17 /*
  18  * Extended attributes are stored directly in inodes (on file systems with
  19  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  20  * field contains the block number if an inode uses an additional block. All
  21  * attributes must fit in the inode and one additional block. Blocks that
  22  * contain the identical set of attributes may be shared among several inodes.
  23  * Identical blocks are detected by keeping a cache of blocks that have
  24  * recently been accessed.
  25  *
  26  * The attributes in inodes and on blocks have a different header; the entries
  27  * are stored in the same format:
  28  *
  29  *   +------------------+
  30  *   | header           |
  31  *   | entry 1          | |
  32  *   | entry 2          | | growing downwards
  33  *   | entry 3          | v
  34  *   | four null bytes  |
  35  *   | . . .            |
  36  *   | value 1          | ^
  37  *   | value 3          | | growing upwards
  38  *   | value 2          | |
  39  *   +------------------+
  40  *
  41  * The header is followed by multiple entry descriptors. In disk blocks, the
  42  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  43  * attribute values are aligned to the end of the block in no specific order.
  44  *
  45  * Locking strategy
  46  * ----------------
  47  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  48  * EA blocks are only changed if they are exclusive to an inode, so
  49  * holding xattr_sem also means that nothing but the EA block's reference
  50  * count can change. Multiple writers to the same block are synchronized
  51  * by the buffer lock.
  52  */
  53
  54 #include <linux/init.h>
  55 #include <linux/fs.h>
  56 #include <linux/slab.h>
  57 #include <linux/mbcache.h>
  58 #include <linux/quotaops.h>
  59 #include <linux/iversion.h>
  60 #include "ext4_jbd2.h"
  61 #include "ext4.h"
  62 #include "xattr.h"
  63 #include "acl.h"
  64
  65 #ifdef EXT4_XATTR_DEBUG
  66 # define ea_idebug(inode, fmt, ...)                                     \
  67         printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",                    \
  68                inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
  69 # define ea_bdebug(bh, fmt, ...)                                        \
  70         printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",                   \
  71                bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
  72 #else
  73 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  74 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  75 #endif
  76
  77 static void ext4_xattr_block_cache_insert(struct mb_cache *,
  78                                           struct buffer_head *);
  79 static struct buffer_head *
  80 ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
  81                             struct mb_cache_entry **);
  82 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
  83                                     size_t value_count);
  84 static void ext4_xattr_rehash(struct ext4_xattr_header *);
  85
  86 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
  87         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  88 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  89         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  90         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  91 #endif
  92         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
  93 #ifdef CONFIG_EXT4_FS_SECURITY
  94         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
  95 #endif
  96 };
  97
  98 const struct xattr_handler *ext4_xattr_handlers[] = {
  99         &ext4_xattr_user_handler,
 100         &ext4_xattr_trusted_handler,
 101 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 102         &posix_acl_access_xattr_handler,
 103         &posix_acl_default_xattr_handler,
 104 #endif
 105 #ifdef CONFIG_EXT4_FS_SECURITY
 106         &ext4_xattr_security_handler,
 107 #endif
 108         NULL
 109 };
 110
 111 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 112                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 113
 114 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 115                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 116
 117 static int
 118 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 119                         struct inode *inode);
 120
 121 #ifdef CONFIG_LOCKDEP
 122 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 123 {
 124         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 125 }
 126 #endif
 127
 128 static __le32 ext4_xattr_block_csum(struct inode *inode,
 129                                     sector_t block_nr,
 130                                     struct ext4_xattr_header *hdr)
 131 {
 132         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 133         __u32 csum;
 134         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 135         __u32 dummy_csum = 0;
 136         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 137
 138         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 139                            sizeof(dsk_block_nr));
 140         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 141         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 142         offset += sizeof(dummy_csum);
 143         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 144                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 145
 146         return cpu_to_le32(csum);
 147 }
 148
 149 static int ext4_xattr_block_csum_verify(struct inode *inode,
 150                                         struct buffer_head *bh)
 151 {
 152         struct ext4_xattr_header *hdr = BHDR(bh);
 153         int ret = 1;
 154
 155         if (ext4_has_metadata_csum(inode->i_sb)) {
 156                 lock_buffer(bh);
 157                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 158                                                         bh->b_blocknr, hdr));
 159                 unlock_buffer(bh);
 160         }
 161         return ret;
 162 }
 163
 164 static void ext4_xattr_block_csum_set(struct inode *inode,
 165                                       struct buffer_head *bh)
 166 {
 167         if (ext4_has_metadata_csum(inode->i_sb))
 168                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 169                                                 bh->b_blocknr, BHDR(bh));
 170 }
 171
 172 static inline const struct xattr_handler *
 173 ext4_xattr_handler(int name_index)
 174 {
 175         const struct xattr_handler *handler = NULL;
 176
 177         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 178                 handler = ext4_xattr_handler_map[name_index];
 179         return handler;
 180 }
 181
 182 static int
 183 ext4_xattr_check_entries(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                 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
 194                         return -EFSCORRUPTED;
 195                 e = next;
 196         }
 197
 198         /* Check the values */
 199         while (!IS_LAST_ENTRY(entry)) {
 200                 u32 size = le32_to_cpu(entry->e_value_size);
 201
 202                 if (size > EXT4_XATTR_SIZE_MAX)
 203                         return -EFSCORRUPTED;
 204
 205                 if (size != 0 && entry->e_value_inum == 0) {
 206                         u16 offs = le16_to_cpu(entry->e_value_offs);
 207                         void *value;
 208
 209                         /*
 210                          * The value cannot overlap the names, and the value
 211                          * with padding cannot extend beyond 'end'.  Check both
 212                          * the padded and unpadded sizes, since the size may
 213                          * overflow to 0 when adding padding.
 214                          */
 215                         if (offs > end - value_start)
 216                                 return -EFSCORRUPTED;
 217                         value = value_start + offs;
 218                         if (value < (void *)e + sizeof(u32) ||
 219                             size > end - value ||
 220                             EXT4_XATTR_SIZE(size) > end - value)
 221                                 return -EFSCORRUPTED;
 222                 }
 223                 entry = EXT4_XATTR_NEXT(entry);
 224         }
 225
 226         return 0;
 227 }
 228
 229 static inline int
 230 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
 231                          const char *function, unsigned int line)
 232 {
 233         int error = -EFSCORRUPTED;
 234
 235         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 236             BHDR(bh)->h_blocks != cpu_to_le32(1))
 237                 goto errout;
 238         if (buffer_verified(bh))
 239                 return 0;
 240
 241         error = -EFSBADCRC;
 242         if (!ext4_xattr_block_csum_verify(inode, bh))
 243                 goto errout;
 244         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 245                                          bh->b_data);
 246 errout:
 247         if (error)
 248                 __ext4_error_inode(inode, function, line, 0,
 249                                    "corrupted xattr block %llu",
 250                                    (unsigned long long) bh->b_blocknr);
 251         else
 252                 set_buffer_verified(bh);
 253         return error;
 254 }
 255
 256 #define ext4_xattr_check_block(inode, bh) \
 257         __ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
 258
 259
 260 static int
 261 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 262                          void *end, const char *function, unsigned int line)
 263 {
 264         int error = -EFSCORRUPTED;
 265
 266         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 267             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 268                 goto errout;
 269         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 270 errout:
 271         if (error)
 272                 __ext4_error_inode(inode, function, line, 0,
 273                                    "corrupted in-inode xattr");
 274         return error;
 275 }
 276
 277 #define xattr_check_inode(inode, header, end) \
 278         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 279
 280 static int
 281 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
 282                  void *end, int name_index, const char *name, int sorted)
 283 {
 284         struct ext4_xattr_entry *entry, *next;
 285         size_t name_len;
 286         int cmp = 1;
 287
 288         if (name == NULL)
 289                 return -EINVAL;
 290         name_len = strlen(name);
 291         for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
 292                 next = EXT4_XATTR_NEXT(entry);
 293                 if ((void *) next >= end) {
 294                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
 295                         return -EFSCORRUPTED;
 296                 }
 297                 cmp = name_index - entry->e_name_index;
 298                 if (!cmp)
 299                         cmp = name_len - entry->e_name_len;
 300                 if (!cmp)
 301                         cmp = memcmp(name, entry->e_name, name_len);
 302                 if (cmp <= 0 && (sorted || cmp == 0))
 303                         break;
 304         }
 305         *pentry = entry;
 306         return cmp ? -ENODATA : 0;
 307 }
 308
 309 static u32
 310 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 311 {
 312         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 313 }
 314
 315 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 316 {
 317         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 318                 (u32) inode_peek_iversion_raw(ea_inode);
 319 }
 320
 321 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 322 {
 323         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 324         inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
 325 }
 326
 327 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 328 {
 329         return (u32)ea_inode->i_atime.tv_sec;
 330 }
 331
 332 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 333 {
 334         ea_inode->i_atime.tv_sec = hash;
 335 }
 336
 337 /*
 338  * Read the EA value from an inode.
 339  */
 340 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 341 {
 342         int blocksize = 1 << ea_inode->i_blkbits;
 343         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 344         int tail_size = (size % blocksize) ?: blocksize;
 345         struct buffer_head *bhs_inline[8];
 346         struct buffer_head **bhs = bhs_inline;
 347         int i, ret;
 348
 349         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 350                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 351                 if (!bhs)
 352                         return -ENOMEM;
 353         }
 354
 355         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 356                                true /* wait */, bhs);
 357         if (ret)
 358                 goto free_bhs;
 359
 360         for (i = 0; i < bh_count; i++) {
 361                 /* There shouldn't be any holes in ea_inode. */
 362                 if (!bhs[i]) {
 363                         ret = -EFSCORRUPTED;
 364                         goto put_bhs;
 365                 }
 366                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 367                        i < bh_count - 1 ? blocksize : tail_size);
 368         }
 369         ret = 0;
 370 put_bhs:
 371         for (i = 0; i < bh_count; i++)
 372                 brelse(bhs[i]);
 373 free_bhs:
 374         if (bhs != bhs_inline)
 375                 kfree(bhs);
 376         return ret;
 377 }
 378
 379 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 380
 381 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 382                                  u32 ea_inode_hash, struct inode **ea_inode)
 383 {
 384         struct inode *inode;
 385         int err;
 386
 387         inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
 388         if (IS_ERR(inode)) {
 389                 err = PTR_ERR(inode);
 390                 ext4_error(parent->i_sb,
 391                            "error while reading EA inode %lu err=%d", ea_ino,
 392                            err);
 393                 return err;
 394         }
 395
 396         if (is_bad_inode(inode)) {
 397                 ext4_error(parent->i_sb,
 398                            "error while reading EA inode %lu is_bad_inode",
 399                            ea_ino);
 400                 err = -EIO;
 401                 goto error;
 402         }
 403
 404         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 405                 ext4_error(parent->i_sb,
 406                            "EA inode %lu does not have EXT4_EA_INODE_FL flag",
 407                             ea_ino);
 408                 err = -EINVAL;
 409                 goto error;
 410         }
 411
 412         ext4_xattr_inode_set_class(inode);
 413
 414         /*
 415          * Check whether this is an old Lustre-style xattr inode. Lustre
 416          * implementation does not have hash validation, rather it has a
 417          * backpointer from ea_inode to the parent inode.
 418          */
 419         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 420             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 421             inode->i_generation == parent->i_generation) {
 422                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 423                 ext4_xattr_inode_set_ref(inode, 1);
 424         } else {
 425                 inode_lock(inode);
 426                 inode->i_flags |= S_NOQUOTA;
 427                 inode_unlock(inode);
 428         }
 429
 430         *ea_inode = inode;
 431         return 0;
 432 error:
 433         iput(inode);
 434         return err;
 435 }
 436
 437 static int
 438 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 439                                struct ext4_xattr_entry *entry, void *buffer,
 440                                size_t size)
 441 {
 442         u32 hash;
 443
 444         /* Verify stored hash matches calculated hash. */
 445         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 446         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 447                 return -EFSCORRUPTED;
 448
 449         if (entry) {
 450                 __le32 e_hash, tmp_data;
 451
 452                 /* Verify entry hash. */
 453                 tmp_data = cpu_to_le32(hash);
 454                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 455                                                &tmp_data, 1);
 456                 if (e_hash != entry->e_hash)
 457                         return -EFSCORRUPTED;
 458         }
 459         return 0;
 460 }
 461
 462 /*
 463  * Read xattr value from the EA inode.
 464  */
 465 static int
 466 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 467                      void *buffer, size_t size)
 468 {
 469         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 470         struct inode *ea_inode;
 471         int err;
 472
 473         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 474                                     le32_to_cpu(entry->e_hash), &ea_inode);
 475         if (err) {
 476                 ea_inode = NULL;
 477                 goto out;
 478         }
 479
 480         if (i_size_read(ea_inode) != size) {
 481                 ext4_warning_inode(ea_inode,
 482                                    "ea_inode file size=%llu entry size=%zu",
 483                                    i_size_read(ea_inode), size);
 484                 err = -EFSCORRUPTED;
 485                 goto out;
 486         }
 487
 488         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 489         if (err)
 490                 goto out;
 491
 492         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 493                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 494                                                      size);
 495                 if (err) {
 496                         ext4_warning_inode(ea_inode,
 497                                            "EA inode hash validation failed");
 498                         goto out;
 499                 }
 500
 501                 if (ea_inode_cache)
 502                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 503                                         ext4_xattr_inode_get_hash(ea_inode),
 504                                         ea_inode->i_ino, true /* reusable */);
 505         }
 506 out:
 507         iput(ea_inode);
 508         return err;
 509 }
 510
 511 static int
 512 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 513                      void *buffer, size_t buffer_size)
 514 {
 515         struct buffer_head *bh = NULL;
 516         struct ext4_xattr_entry *entry;
 517         size_t size;
 518         void *end;
 519         int error;
 520         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 521
 522         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 523                   name_index, name, buffer, (long)buffer_size);
 524
 525         if (!EXT4_I(inode)->i_file_acl)
 526                 return -ENODATA;
 527         ea_idebug(inode, "reading block %llu",
 528                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 529         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 530         if (IS_ERR(bh))
 531                 return PTR_ERR(bh);
 532         ea_bdebug(bh, "b_count=%d, refcount=%d",
 533                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 534         error = ext4_xattr_check_block(inode, bh);
 535         if (error)
 536                 goto cleanup;
 537         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 538         entry = BFIRST(bh);
 539         end = bh->b_data + bh->b_size;
 540         error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
 541         if (error)
 542                 goto cleanup;
 543         size = le32_to_cpu(entry->e_value_size);
 544         error = -ERANGE;
 545         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 546                 goto cleanup;
 547         if (buffer) {
 548                 if (size > buffer_size)
 549                         goto cleanup;
 550                 if (entry->e_value_inum) {
 551                         error = ext4_xattr_inode_get(inode, entry, buffer,
 552                                                      size);
 553                         if (error)
 554                                 goto cleanup;
 555                 } else {
 556                         u16 offset = le16_to_cpu(entry->e_value_offs);
 557                         void *p = bh->b_data + offset;
 558
 559                         if (unlikely(p + size > end))
 560                                 goto cleanup;
 561                         memcpy(buffer, p, size);
 562                 }
 563         }
 564         error = size;
 565
 566 cleanup:
 567         brelse(bh);
 568         return error;
 569 }
 570
 571 int
 572 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 573                      void *buffer, size_t buffer_size)
 574 {
 575         struct ext4_xattr_ibody_header *header;
 576         struct ext4_xattr_entry *entry;
 577         struct ext4_inode *raw_inode;
 578         struct ext4_iloc iloc;
 579         size_t size;
 580         void *end;
 581         int error;
 582
 583         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 584                 return -ENODATA;
 585         error = ext4_get_inode_loc(inode, &iloc);
 586         if (error)
 587                 return error;
 588         raw_inode = ext4_raw_inode(&iloc);
 589         header = IHDR(inode, raw_inode);
 590         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 591         error = xattr_check_inode(inode, header, end);
 592         if (error)
 593                 goto cleanup;
 594         entry = IFIRST(header);
 595         error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
 596         if (error)
 597                 goto cleanup;
 598         size = le32_to_cpu(entry->e_value_size);
 599         error = -ERANGE;
 600         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 601                 goto cleanup;
 602         if (buffer) {
 603                 if (size > buffer_size)
 604                         goto cleanup;
 605                 if (entry->e_value_inum) {
 606                         error = ext4_xattr_inode_get(inode, entry, buffer,
 607                                                      size);
 608                         if (error)
 609                                 goto cleanup;
 610                 } else {
 611                         u16 offset = le16_to_cpu(entry->e_value_offs);
 612                         void *p = (void *)IFIRST(header) + offset;
 613
 614                         if (unlikely(p + size > end))
 615                                 goto cleanup;
 616                         memcpy(buffer, p, size);
 617                 }
 618         }
 619         error = size;
 620
 621 cleanup:
 622         brelse(iloc.bh);
 623         return error;
 624 }
 625
 626 /*
 627  * ext4_xattr_get()
 628  *
 629  * Copy an extended attribute into the buffer
 630  * provided, or compute the buffer size required.
 631  * Buffer is NULL to compute the size of the buffer required.
 632  *
 633  * Returns a negative error number on failure, or the number of bytes
 634  * used / required on success.
 635  */
 636 int
 637 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 638                void *buffer, size_t buffer_size)
 639 {
 640         int error;
 641
 642         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 643                 return -EIO;
 644
 645         if (strlen(name) > 255)
 646                 return -ERANGE;
 647
 648         down_read(&EXT4_I(inode)->xattr_sem);
 649         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 650                                      buffer_size);
 651         if (error == -ENODATA)
 652                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 653                                              buffer_size);
 654         up_read(&EXT4_I(inode)->xattr_sem);
 655         return error;
 656 }
 657
 658 static int
 659 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 660                         char *buffer, size_t buffer_size)
 661 {
 662         size_t rest = buffer_size;
 663
 664         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 665                 const struct xattr_handler *handler =
 666                         ext4_xattr_handler(entry->e_name_index);
 667
 668                 if (handler && (!handler->list || handler->list(dentry))) {
 669                         const char *prefix = handler->prefix ?: handler->name;
 670                         size_t prefix_len = strlen(prefix);
 671                         size_t size = prefix_len + entry->e_name_len + 1;
 672
 673                         if (buffer) {
 674                                 if (size > rest)
 675                                         return -ERANGE;
 676                                 memcpy(buffer, prefix, prefix_len);
 677                                 buffer += prefix_len;
 678                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 679                                 buffer += entry->e_name_len;
 680                                 *buffer++ = 0;
 681                         }
 682                         rest -= size;
 683                 }
 684         }
 685         return buffer_size - rest;  /* total size */
 686 }
 687
 688 static int
 689 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 690 {
 691         struct inode *inode = d_inode(dentry);
 692         struct buffer_head *bh = NULL;
 693         int error;
 694
 695         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 696                   buffer, (long)buffer_size);
 697
 698         if (!EXT4_I(inode)->i_file_acl)
 699                 return 0;
 700         ea_idebug(inode, "reading block %llu",
 701                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 702         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 703         if (IS_ERR(bh))
 704                 return PTR_ERR(bh);
 705         ea_bdebug(bh, "b_count=%d, refcount=%d",
 706                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 707         error = ext4_xattr_check_block(inode, bh);
 708         if (error)
 709                 goto cleanup;
 710         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 711         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
 712                                         buffer_size);
 713 cleanup:
 714         brelse(bh);
 715         return error;
 716 }
 717
 718 static int
 719 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 720 {
 721         struct inode *inode = d_inode(dentry);
 722         struct ext4_xattr_ibody_header *header;
 723         struct ext4_inode *raw_inode;
 724         struct ext4_iloc iloc;
 725         void *end;
 726         int error;
 727
 728         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 729                 return 0;
 730         error = ext4_get_inode_loc(inode, &iloc);
 731         if (error)
 732                 return error;
 733         raw_inode = ext4_raw_inode(&iloc);
 734         header = IHDR(inode, raw_inode);
 735         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 736         error = xattr_check_inode(inode, header, end);
 737         if (error)
 738                 goto cleanup;
 739         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 740                                         buffer, buffer_size);
 741
 742 cleanup:
 743         brelse(iloc.bh);
 744         return error;
 745 }
 746
 747 /*
 748  * Inode operation listxattr()
 749  *
 750  * d_inode(dentry)->i_rwsem: don't care
 751  *
 752  * Copy a list of attribute names into the buffer
 753  * provided, or compute the buffer size required.
 754  * Buffer is NULL to compute the size of the buffer required.
 755  *
 756  * Returns a negative error number on failure, or the number of bytes
 757  * used / required on success.
 758  */
 759 ssize_t
 760 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 761 {
 762         int ret, ret2;
 763
 764         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 765         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 766         if (ret < 0)
 767                 goto errout;
 768         if (buffer) {
 769                 buffer += ret;
 770                 buffer_size -= ret;
 771         }
 772         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 773         if (ret < 0)
 774                 goto errout;
 775         ret += ret2;
 776 errout:
 777         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 778         return ret;
 779 }
 780
 781 /*
 782  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 783  * not set, set it.
 784  */
 785 static void ext4_xattr_update_super_block(handle_t *handle,
 786                                           struct super_block *sb)
 787 {
 788         if (ext4_has_feature_xattr(sb))
 789                 return;
 790
 791         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 792         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 793                 ext4_set_feature_xattr(sb);
 794                 ext4_handle_dirty_super(handle, sb);
 795         }
 796 }
 797
 798 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 799 {
 800         struct ext4_iloc iloc = { .bh = NULL };
 801         struct buffer_head *bh = NULL;
 802         struct ext4_inode *raw_inode;
 803         struct ext4_xattr_ibody_header *header;
 804         struct ext4_xattr_entry *entry;
 805         qsize_t ea_inode_refs = 0;
 806         void *end;
 807         int ret;
 808
 809         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 810
 811         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 812                 ret = ext4_get_inode_loc(inode, &iloc);
 813                 if (ret)
 814                         goto out;
 815                 raw_inode = ext4_raw_inode(&iloc);
 816                 header = IHDR(inode, raw_inode);
 817                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 818                 ret = xattr_check_inode(inode, header, end);
 819                 if (ret)
 820                         goto out;
 821
 822                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 823                      entry = EXT4_XATTR_NEXT(entry))
 824                         if (entry->e_value_inum)
 825                                 ea_inode_refs++;
 826         }
 827
 828         if (EXT4_I(inode)->i_file_acl) {
 829                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 830                 if (IS_ERR(bh)) {
 831                         ret = PTR_ERR(bh);
 832                         bh = NULL;
 833                         goto out;
 834                 }
 835
 836                 ret = ext4_xattr_check_block(inode, bh);
 837                 if (ret)
 838                         goto out;
 839
 840                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 841                      entry = EXT4_XATTR_NEXT(entry))
 842                         if (entry->e_value_inum)
 843                                 ea_inode_refs++;
 844         }
 845         *usage = ea_inode_refs + 1;
 846         ret = 0;
 847 out:
 848         brelse(iloc.bh);
 849         brelse(bh);
 850         return ret;
 851 }
 852
 853 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 854 {
 855         struct super_block *sb = inode->i_sb;
 856         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 857                                     inode->i_blkbits);
 858         size_t mask = ~(cluster_size - 1);
 859
 860         return (length + cluster_size - 1) & mask;
 861 }
 862
 863 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 864 {
 865         int err;
 866
 867         err = dquot_alloc_inode(inode);
 868         if (err)
 869                 return err;
 870         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 871         if (err)
 872                 dquot_free_inode(inode);
 873         return err;
 874 }
 875
 876 static void ext4_xattr_inode_free_quota(struct inode *parent,
 877                                         struct inode *ea_inode,
 878                                         size_t len)
 879 {
 880         if (ea_inode &&
 881             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 882                 return;
 883         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 884         dquot_free_inode(parent);
 885 }
 886
 887 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 888                              struct buffer_head *block_bh, size_t value_len,
 889                              bool is_create)
 890 {
 891         int credits;
 892         int blocks;
 893
 894         /*
 895          * 1) Owner inode update
 896          * 2) Ref count update on old xattr block
 897          * 3) new xattr block
 898          * 4) block bitmap update for new xattr block
 899          * 5) group descriptor for new xattr block
 900          * 6) block bitmap update for old xattr block
 901          * 7) group descriptor for old block
 902          *
 903          * 6 & 7 can happen if we have two racing threads T_a and T_b
 904          * which are each trying to set an xattr on inodes I_a and I_b
 905          * which were both initially sharing an xattr block.
 906          */
 907         credits = 7;
 908
 909         /* Quota updates. */
 910         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 911
 912         /*
 913          * In case of inline data, we may push out the data to a block,
 914          * so we need to reserve credits for this eventuality
 915          */
 916         if (inode && ext4_has_inline_data(inode))
 917                 credits += ext4_writepage_trans_blocks(inode) + 1;
 918
 919         /* We are done if ea_inode feature is not enabled. */
 920         if (!ext4_has_feature_ea_inode(sb))
 921                 return credits;
 922
 923         /* New ea_inode, inode map, block bitmap, group descriptor. */
 924         credits += 4;
 925
 926         /* Data blocks. */
 927         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 928
 929         /* Indirection block or one level of extent tree. */
 930         blocks += 1;
 931
 932         /* Block bitmap and group descriptor updates for each block. */
 933         credits += blocks * 2;
 934
 935         /* Blocks themselves. */
 936         credits += blocks;
 937
 938         if (!is_create) {
 939                 /* Dereference ea_inode holding old xattr value.
 940                  * Old ea_inode, inode map, block bitmap, group descriptor.
 941                  */
 942                 credits += 4;
 943
 944                 /* Data blocks for old ea_inode. */
 945                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 946
 947                 /* Indirection block or one level of extent tree for old
 948                  * ea_inode.
 949                  */
 950                 blocks += 1;
 951
 952                 /* Block bitmap and group descriptor updates for each block. */
 953                 credits += blocks * 2;
 954         }
 955
 956         /* We may need to clone the existing xattr block in which case we need
 957          * to increment ref counts for existing ea_inodes referenced by it.
 958          */
 959         if (block_bh) {
 960                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 961
 962                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 963                         if (entry->e_value_inum)
 964                                 /* Ref count update on ea_inode. */
 965                                 credits += 1;
 966         }
 967         return credits;
 968 }
 969
 970 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 971                                        int ref_change)
 972 {
 973         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
 974         struct ext4_iloc iloc;
 975         s64 ref_count;
 976         u32 hash;
 977         int ret;
 978
 979         inode_lock(ea_inode);
 980
 981         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
 982         if (ret)
 983                 goto out;
 984
 985         ref_count = ext4_xattr_inode_get_ref(ea_inode);
 986         ref_count += ref_change;
 987         ext4_xattr_inode_set_ref(ea_inode, ref_count);
 988
 989         if (ref_change > 0) {
 990                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
 991                           ea_inode->i_ino, ref_count);
 992
 993                 if (ref_count == 1) {
 994                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
 995                                   ea_inode->i_ino, ea_inode->i_nlink);
 996
 997                         set_nlink(ea_inode, 1);
 998                         ext4_orphan_del(handle, ea_inode);
 999
1000                         if (ea_inode_cache) {
1001                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1002                                 mb_cache_entry_create(ea_inode_cache,
1003                                                       GFP_NOFS, hash,
1004                                                       ea_inode->i_ino,
1005                                                       true /* reusable */);
1006                         }
1007                 }
1008         } else {
1009                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1010                           ea_inode->i_ino, ref_count);
1011
1012                 if (ref_count == 0) {
1013                         WARN_ONCE(ea_inode->i_nlink != 1,
1014                                   "EA inode %lu i_nlink=%u",
1015                                   ea_inode->i_ino, ea_inode->i_nlink);
1016
1017                         clear_nlink(ea_inode);
1018                         ext4_orphan_add(handle, ea_inode);
1019
1020                         if (ea_inode_cache) {
1021                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1022                                 mb_cache_entry_delete(ea_inode_cache, hash,
1023                                                       ea_inode->i_ino);
1024                         }
1025                 }
1026         }
1027
1028         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1029         if (ret)
1030                 ext4_warning_inode(ea_inode,
1031                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1032 out:
1033         inode_unlock(ea_inode);
1034         return ret;
1035 }
1036
1037 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1038 {
1039         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1040 }
1041
1042 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1043 {
1044         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1045 }
1046
1047 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1048                                         struct ext4_xattr_entry *first)
1049 {
1050         struct inode *ea_inode;
1051         struct ext4_xattr_entry *entry;
1052         struct ext4_xattr_entry *failed_entry;
1053         unsigned int ea_ino;
1054         int err, saved_err;
1055
1056         for (entry = first; !IS_LAST_ENTRY(entry);
1057              entry = EXT4_XATTR_NEXT(entry)) {
1058                 if (!entry->e_value_inum)
1059                         continue;
1060                 ea_ino = le32_to_cpu(entry->e_value_inum);
1061                 err = ext4_xattr_inode_iget(parent, ea_ino,
1062                                             le32_to_cpu(entry->e_hash),
1063                                             &ea_inode);
1064                 if (err)
1065                         goto cleanup;
1066                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1067                 if (err) {
1068                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1069                         iput(ea_inode);
1070                         goto cleanup;
1071                 }
1072                 iput(ea_inode);
1073         }
1074         return 0;
1075
1076 cleanup:
1077         saved_err = err;
1078         failed_entry = entry;
1079
1080         for (entry = first; entry != failed_entry;
1081              entry = EXT4_XATTR_NEXT(entry)) {
1082                 if (!entry->e_value_inum)
1083                         continue;
1084                 ea_ino = le32_to_cpu(entry->e_value_inum);
1085                 err = ext4_xattr_inode_iget(parent, ea_ino,
1086                                             le32_to_cpu(entry->e_hash),
1087                                             &ea_inode);
1088                 if (err) {
1089                         ext4_warning(parent->i_sb,
1090                                      "cleanup ea_ino %u iget error %d", ea_ino,
1091                                      err);
1092                         continue;
1093                 }
1094                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1095                 if (err)
1096                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1097                                            err);
1098                 iput(ea_inode);
1099         }
1100         return saved_err;
1101 }
1102
1103 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1104                         struct buffer_head *bh, bool block_csum, bool dirty)
1105 {
1106         int error;
1107
1108         if (bh && dirty) {
1109                 if (block_csum)
1110                         ext4_xattr_block_csum_set(inode, bh);
1111                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1112                 if (error) {
1113                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1114                                      error);
1115                         return error;
1116                 }
1117         }
1118         return 0;
1119 }
1120
1121 static void
1122 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1123                              struct buffer_head *bh,
1124                              struct ext4_xattr_entry *first, bool block_csum,
1125                              struct ext4_xattr_inode_array **ea_inode_array,
1126                              int extra_credits, bool skip_quota)
1127 {
1128         struct inode *ea_inode;
1129         struct ext4_xattr_entry *entry;
1130         bool dirty = false;
1131         unsigned int ea_ino;
1132         int err;
1133         int credits;
1134
1135         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1136         credits = 2 + extra_credits;
1137
1138         for (entry = first; !IS_LAST_ENTRY(entry);
1139              entry = EXT4_XATTR_NEXT(entry)) {
1140                 if (!entry->e_value_inum)
1141                         continue;
1142                 ea_ino = le32_to_cpu(entry->e_value_inum);
1143                 err = ext4_xattr_inode_iget(parent, ea_ino,
1144                                             le32_to_cpu(entry->e_hash),
1145                                             &ea_inode);
1146                 if (err)
1147                         continue;
1148
1149                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1150                 if (err) {
1151                         ext4_warning_inode(ea_inode,
1152                                            "Expand inode array err=%d", err);
1153                         iput(ea_inode);
1154                         continue;
1155                 }
1156
1157                 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1158                         ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1159                                               dirty));
1160                 if (err < 0) {
1161                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1162                                            err);
1163                         continue;
1164                 }
1165                 if (err > 0) {
1166                         err = ext4_journal_get_write_access(handle, bh);
1167                         if (err) {
1168                                 ext4_warning_inode(ea_inode,
1169                                                 "Re-get write access err=%d",
1170                                                 err);
1171                                 continue;
1172                         }
1173                 }
1174
1175                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1176                 if (err) {
1177                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1178                                            err);
1179                         continue;
1180                 }
1181
1182                 if (!skip_quota)
1183                         ext4_xattr_inode_free_quota(parent, ea_inode,
1184                                               le32_to_cpu(entry->e_value_size));
1185
1186                 /*
1187                  * Forget about ea_inode within the same transaction that
1188                  * decrements the ref count. This avoids duplicate decrements in
1189                  * case the rest of the work spills over to subsequent
1190                  * transactions.
1191                  */
1192                 entry->e_value_inum = 0;
1193                 entry->e_value_size = 0;
1194
1195                 dirty = true;
1196         }
1197
1198         if (dirty) {
1199                 /*
1200                  * Note that we are deliberately skipping csum calculation for
1201                  * the final update because we do not expect any journal
1202                  * restarts until xattr block is freed.
1203                  */
1204
1205                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1206                 if (err)
1207                         ext4_warning_inode(parent,
1208                                            "handle dirty metadata err=%d", err);
1209         }
1210 }
1211
1212 /*
1213  * Release the xattr block BH: If the reference count is > 1, decrement it;
1214  * otherwise free the block.
1215  */
1216 static void
1217 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1218                          struct buffer_head *bh,
1219                          struct ext4_xattr_inode_array **ea_inode_array,
1220                          int extra_credits)
1221 {
1222         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1223         u32 hash, ref;
1224         int error = 0;
1225
1226         BUFFER_TRACE(bh, "get_write_access");
1227         error = ext4_journal_get_write_access(handle, bh);
1228         if (error)
1229                 goto out;
1230
1231         lock_buffer(bh);
1232         hash = le32_to_cpu(BHDR(bh)->h_hash);
1233         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1234         if (ref == 1) {
1235                 ea_bdebug(bh, "refcount now=0; freeing");
1236                 /*
1237                  * This must happen under buffer lock for
1238                  * ext4_xattr_block_set() to reliably detect freed block
1239                  */
1240                 if (ea_block_cache)
1241                         mb_cache_entry_delete(ea_block_cache, hash,
1242                                               bh->b_blocknr);
1243                 get_bh(bh);
1244                 unlock_buffer(bh);
1245
1246                 if (ext4_has_feature_ea_inode(inode->i_sb))
1247                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1248                                                      BFIRST(bh),
1249                                                      true /* block_csum */,
1250                                                      ea_inode_array,
1251                                                      extra_credits,
1252                                                      true /* skip_quota */);
1253                 ext4_free_blocks(handle, inode, bh, 0, 1,
1254                                  EXT4_FREE_BLOCKS_METADATA |
1255                                  EXT4_FREE_BLOCKS_FORGET);
1256         } else {
1257                 ref--;
1258                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1259                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1260                         struct mb_cache_entry *ce;
1261
1262                         if (ea_block_cache) {
1263                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1264                                                         bh->b_blocknr);
1265                                 if (ce) {
1266                                         ce->e_reusable = 1;
1267                                         mb_cache_entry_put(ea_block_cache, ce);
1268                                 }
1269                         }
1270                 }
1271
1272                 ext4_xattr_block_csum_set(inode, bh);
1273                 /*
1274                  * Beware of this ugliness: Releasing of xattr block references
1275                  * from different inodes can race and so we have to protect
1276                  * from a race where someone else frees the block (and releases
1277                  * its journal_head) before we are done dirtying the buffer. In
1278                  * nojournal mode this race is harmless and we actually cannot
1279                  * call ext4_handle_dirty_metadata() with locked buffer as
1280                  * that function can call sync_dirty_buffer() so for that case
1281                  * we handle the dirtying after unlocking the buffer.
1282                  */
1283                 if (ext4_handle_valid(handle))
1284                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1285                 unlock_buffer(bh);
1286                 if (!ext4_handle_valid(handle))
1287                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1288                 if (IS_SYNC(inode))
1289                         ext4_handle_sync(handle);
1290                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1291                 ea_bdebug(bh, "refcount now=%d; releasing",
1292                           le32_to_cpu(BHDR(bh)->h_refcount));
1293         }
1294 out:
1295         ext4_std_error(inode->i_sb, error);
1296         return;
1297 }
1298
1299 /*
1300  * Find the available free space for EAs. This also returns the total number of
1301  * bytes used by EA entries.
1302  */
1303 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1304                                     size_t *min_offs, void *base, int *total)
1305 {
1306         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1307                 if (!last->e_value_inum && last->e_value_size) {
1308                         size_t offs = le16_to_cpu(last->e_value_offs);
1309                         if (offs < *min_offs)
1310                                 *min_offs = offs;
1311                 }
1312                 if (total)
1313                         *total += EXT4_XATTR_LEN(last->e_name_len);
1314         }
1315         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1316 }
1317
1318 /*
1319  * Write the value of the EA in an inode.
1320  */
1321 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1322                                   const void *buf, int bufsize)
1323 {
1324         struct buffer_head *bh = NULL;
1325         unsigned long block = 0;
1326         int blocksize = ea_inode->i_sb->s_blocksize;
1327         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1328         int csize, wsize = 0;
1329         int ret = 0;
1330         int retries = 0;
1331
1332 retry:
1333         while (ret >= 0 && ret < max_blocks) {
1334                 struct ext4_map_blocks map;
1335                 map.m_lblk = block += ret;
1336                 map.m_len = max_blocks -= ret;
1337
1338                 ret = ext4_map_blocks(handle, ea_inode, &map,
1339                                       EXT4_GET_BLOCKS_CREATE);
1340                 if (ret <= 0) {
1341                         ext4_mark_inode_dirty(handle, ea_inode);
1342                         if (ret == -ENOSPC &&
1343                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1344                                 ret = 0;
1345                                 goto retry;
1346                         }
1347                         break;
1348                 }
1349         }
1350
1351         if (ret < 0)
1352                 return ret;
1353
1354         block = 0;
1355         while (wsize < bufsize) {
1356                 if (bh != NULL)
1357                         brelse(bh);
1358                 csize = (bufsize - wsize) > blocksize ? blocksize :
1359                                                                 bufsize - wsize;
1360                 bh = ext4_getblk(handle, ea_inode, block, 0);
1361                 if (IS_ERR(bh))
1362                         return PTR_ERR(bh);
1363                 if (!bh) {
1364                         WARN_ON_ONCE(1);
1365                         EXT4_ERROR_INODE(ea_inode,
1366                                          "ext4_getblk() return bh = NULL");
1367                         return -EFSCORRUPTED;
1368                 }
1369                 ret = ext4_journal_get_write_access(handle, bh);
1370                 if (ret)
1371                         goto out;
1372
1373                 memcpy(bh->b_data, buf, csize);
1374                 set_buffer_uptodate(bh);
1375                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1376
1377                 buf += csize;
1378                 wsize += csize;
1379                 block += 1;
1380         }
1381
1382         inode_lock(ea_inode);
1383         i_size_write(ea_inode, wsize);
1384         ext4_update_i_disksize(ea_inode, wsize);
1385         inode_unlock(ea_inode);
1386
1387         ext4_mark_inode_dirty(handle, ea_inode);
1388
1389 out:
1390         brelse(bh);
1391
1392         return ret;
1393 }
1394
1395 /*
1396  * Create an inode to store the value of a large EA.
1397  */
1398 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1399                                              struct inode *inode, u32 hash)
1400 {
1401         struct inode *ea_inode = NULL;
1402         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1403         int err;
1404
1405         /*
1406          * Let the next inode be the goal, so we try and allocate the EA inode
1407          * in the same group, or nearby one.
1408          */
1409         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1410                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1411                                   EXT4_EA_INODE_FL);
1412         if (!IS_ERR(ea_inode)) {
1413                 ea_inode->i_op = &ext4_file_inode_operations;
1414                 ea_inode->i_fop = &ext4_file_operations;
1415                 ext4_set_aops(ea_inode);
1416                 ext4_xattr_inode_set_class(ea_inode);
1417                 unlock_new_inode(ea_inode);
1418                 ext4_xattr_inode_set_ref(ea_inode, 1);
1419                 ext4_xattr_inode_set_hash(ea_inode, hash);
1420                 err = ext4_mark_inode_dirty(handle, ea_inode);
1421                 if (!err)
1422                         err = ext4_inode_attach_jinode(ea_inode);
1423                 if (err) {
1424                         iput(ea_inode);
1425                         return ERR_PTR(err);
1426                 }
1427
1428                 /*
1429                  * Xattr inodes are shared therefore quota charging is performed
1430                  * at a higher level.
1431                  */
1432                 dquot_free_inode(ea_inode);
1433                 dquot_drop(ea_inode);
1434                 inode_lock(ea_inode);
1435                 ea_inode->i_flags |= S_NOQUOTA;
1436                 inode_unlock(ea_inode);
1437         }
1438
1439         return ea_inode;
1440 }
1441
1442 static struct inode *
1443 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1444                             size_t value_len, u32 hash)
1445 {
1446         struct inode *ea_inode;
1447         struct mb_cache_entry *ce;
1448         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1449         void *ea_data;
1450
1451         if (!ea_inode_cache)
1452                 return NULL;
1453
1454         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1455         if (!ce)
1456                 return NULL;
1457
1458         ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
1459         if (!ea_data) {
1460                 mb_cache_entry_put(ea_inode_cache, ce);
1461                 return NULL;
1462         }
1463
1464         while (ce) {
1465                 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1466                                      EXT4_IGET_NORMAL);
1467                 if (!IS_ERR(ea_inode) &&
1468                     !is_bad_inode(ea_inode) &&
1469                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1470                     i_size_read(ea_inode) == value_len &&
1471                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1472                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1473                                                     value_len) &&
1474                     !memcmp(value, ea_data, value_len)) {
1475                         mb_cache_entry_touch(ea_inode_cache, ce);
1476                         mb_cache_entry_put(ea_inode_cache, ce);
1477                         kvfree(ea_data);
1478                         return ea_inode;
1479                 }
1480
1481                 if (!IS_ERR(ea_inode))
1482                         iput(ea_inode);
1483                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1484         }
1485         kvfree(ea_data);
1486         return NULL;
1487 }
1488
1489 /*
1490  * Add value of the EA in an inode.
1491  */
1492 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1493                                           const void *value, size_t value_len,
1494                                           struct inode **ret_inode)
1495 {
1496         struct inode *ea_inode;
1497         u32 hash;
1498         int err;
1499
1500         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1501         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1502         if (ea_inode) {
1503                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1504                 if (err) {
1505                         iput(ea_inode);
1506                         return err;
1507                 }
1508
1509                 *ret_inode = ea_inode;
1510                 return 0;
1511         }
1512
1513         /* Create an inode for the EA value */
1514         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1515         if (IS_ERR(ea_inode))
1516                 return PTR_ERR(ea_inode);
1517
1518         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1519         if (err) {
1520                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1521                 iput(ea_inode);
1522                 return err;
1523         }
1524
1525         if (EA_INODE_CACHE(inode))
1526                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1527                                       ea_inode->i_ino, true /* reusable */);
1528
1529         *ret_inode = ea_inode;
1530         return 0;
1531 }
1532
1533 /*
1534  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1535  * feature is enabled.
1536  */
1537 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1538
1539 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1540                                 struct ext4_xattr_search *s,
1541                                 handle_t *handle, struct inode *inode,
1542                                 bool is_block)
1543 {
1544         struct ext4_xattr_entry *last, *next;
1545         struct ext4_xattr_entry *here = s->here;
1546         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1547         int in_inode = i->in_inode;
1548         struct inode *old_ea_inode = NULL;
1549         struct inode *new_ea_inode = NULL;
1550         size_t old_size, new_size;
1551         int ret;
1552
1553         /* Space used by old and new values. */
1554         old_size = (!s->not_found && !here->e_value_inum) ?
1555                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1556         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1557
1558         /*
1559          * Optimization for the simple case when old and new values have the
1560          * same padded sizes. Not applicable if external inodes are involved.
1561          */
1562         if (new_size && new_size == old_size) {
1563                 size_t offs = le16_to_cpu(here->e_value_offs);
1564                 void *val = s->base + offs;
1565
1566                 here->e_value_size = cpu_to_le32(i->value_len);
1567                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1568                         memset(val, 0, new_size);
1569                 } else {
1570                         memcpy(val, i->value, i->value_len);
1571                         /* Clear padding bytes. */
1572                         memset(val + i->value_len, 0, new_size - i->value_len);
1573                 }
1574                 goto update_hash;
1575         }
1576
1577         /* Compute min_offs and last. */
1578         last = s->first;
1579         for (; !IS_LAST_ENTRY(last); last = next) {
1580                 next = EXT4_XATTR_NEXT(last);
1581                 if ((void *)next >= s->end) {
1582                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1583                         ret = -EFSCORRUPTED;
1584                         goto out;
1585                 }
1586                 if (!last->e_value_inum && last->e_value_size) {
1587                         size_t offs = le16_to_cpu(last->e_value_offs);
1588                         if (offs < min_offs)
1589                                 min_offs = offs;
1590                 }
1591         }
1592
1593         /* Check whether we have enough space. */
1594         if (i->value) {
1595                 size_t free;
1596
1597                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1598                 if (!s->not_found)
1599                         free += EXT4_XATTR_LEN(name_len) + old_size;
1600
1601                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1602                         ret = -ENOSPC;
1603                         goto out;
1604                 }
1605
1606                 /*
1607                  * If storing the value in an external inode is an option,
1608                  * reserve space for xattr entries/names in the external
1609                  * attribute block so that a long value does not occupy the
1610                  * whole space and prevent futher entries being added.
1611                  */
1612                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1613                     new_size && is_block &&
1614                     (min_offs + old_size - new_size) <
1615                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1616                         ret = -ENOSPC;
1617                         goto out;
1618                 }
1619         }
1620
1621         /*
1622          * Getting access to old and new ea inodes is subject to failures.
1623          * Finish that work before doing any modifications to the xattr data.
1624          */
1625         if (!s->not_found && here->e_value_inum) {
1626                 ret = ext4_xattr_inode_iget(inode,
1627                                             le32_to_cpu(here->e_value_inum),
1628                                             le32_to_cpu(here->e_hash),
1629                                             &old_ea_inode);
1630                 if (ret) {
1631                         old_ea_inode = NULL;
1632                         goto out;
1633                 }
1634         }
1635         if (i->value && in_inode) {
1636                 WARN_ON_ONCE(!i->value_len);
1637
1638                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1639                 if (ret)
1640                         goto out;
1641
1642                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1643                                                      i->value_len,
1644                                                      &new_ea_inode);
1645                 if (ret) {
1646                         new_ea_inode = NULL;
1647                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1648                         goto out;
1649                 }
1650         }
1651
1652         if (old_ea_inode) {
1653                 /* We are ready to release ref count on the old_ea_inode. */
1654                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1655                 if (ret) {
1656                         /* Release newly required ref count on new_ea_inode. */
1657                         if (new_ea_inode) {
1658                                 int err;
1659
1660                                 err = ext4_xattr_inode_dec_ref(handle,
1661                                                                new_ea_inode);
1662                                 if (err)
1663                                         ext4_warning_inode(new_ea_inode,
1664                                                   "dec ref new_ea_inode err=%d",
1665                                                   err);
1666                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1667                                                             i->value_len);
1668                         }
1669                         goto out;
1670                 }
1671
1672                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1673                                             le32_to_cpu(here->e_value_size));
1674         }
1675
1676         /* No failures allowed past this point. */
1677
1678         if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1679                 /* Remove the old value. */
1680                 void *first_val = s->base + min_offs;
1681                 size_t offs = le16_to_cpu(here->e_value_offs);
1682                 void *val = s->base + offs;
1683
1684                 memmove(first_val + old_size, first_val, val - first_val);
1685                 memset(first_val, 0, old_size);
1686                 min_offs += old_size;
1687
1688                 /* Adjust all value offsets. */
1689                 last = s->first;
1690                 while (!IS_LAST_ENTRY(last)) {
1691                         size_t o = le16_to_cpu(last->e_value_offs);
1692
1693                         if (!last->e_value_inum &&
1694                             last->e_value_size && o < offs)
1695                                 last->e_value_offs = cpu_to_le16(o + old_size);
1696                         last = EXT4_XATTR_NEXT(last);
1697                 }
1698         }
1699
1700         if (!i->value) {
1701                 /* Remove old name. */
1702                 size_t size = EXT4_XATTR_LEN(name_len);
1703
1704                 last = ENTRY((void *)last - size);
1705                 memmove(here, (void *)here + size,
1706                         (void *)last - (void *)here + sizeof(__u32));
1707                 memset(last, 0, size);
1708         } else if (s->not_found) {
1709                 /* Insert new name. */
1710                 size_t size = EXT4_XATTR_LEN(name_len);
1711                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1712
1713                 memmove((void *)here + size, here, rest);
1714                 memset(here, 0, size);
1715                 here->e_name_index = i->name_index;
1716                 here->e_name_len = name_len;
1717                 memcpy(here->e_name, i->name, name_len);
1718         } else {
1719                 /* This is an update, reset value info. */
1720                 here->e_value_inum = 0;
1721                 here->e_value_offs = 0;
1722                 here->e_value_size = 0;
1723         }
1724
1725         if (i->value) {
1726                 /* Insert new value. */
1727                 if (in_inode) {
1728                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1729                 } else if (i->value_len) {
1730                         void *val = s->base + min_offs - new_size;
1731
1732                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1733                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1734                                 memset(val, 0, new_size);
1735                         } else {
1736                                 memcpy(val, i->value, i->value_len);
1737                                 /* Clear padding bytes. */
1738                                 memset(val + i->value_len, 0,
1739                                        new_size - i->value_len);
1740                         }
1741                 }
1742                 here->e_value_size = cpu_to_le32(i->value_len);
1743         }
1744
1745 update_hash:
1746         if (i->value) {
1747                 __le32 hash = 0;
1748
1749                 /* Entry hash calculation. */
1750                 if (in_inode) {
1751                         __le32 crc32c_hash;
1752
1753                         /*
1754                          * Feed crc32c hash instead of the raw value for entry
1755                          * hash calculation. This is to avoid walking
1756                          * potentially long value buffer again.
1757                          */
1758                         crc32c_hash = cpu_to_le32(
1759                                        ext4_xattr_inode_get_hash(new_ea_inode));
1760                         hash = ext4_xattr_hash_entry(here->e_name,
1761                                                      here->e_name_len,
1762                                                      &crc32c_hash, 1);
1763                 } else if (is_block) {
1764                         __le32 *value = s->base + le16_to_cpu(
1765                                                         here->e_value_offs);
1766
1767                         hash = ext4_xattr_hash_entry(here->e_name,
1768                                                      here->e_name_len, value,
1769                                                      new_size >> 2);
1770                 }
1771                 here->e_hash = hash;
1772         }
1773
1774         if (is_block)
1775                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1776
1777         ret = 0;
1778 out:
1779         iput(old_ea_inode);
1780         iput(new_ea_inode);
1781         return ret;
1782 }
1783
1784 struct ext4_xattr_block_find {
1785         struct ext4_xattr_search s;
1786         struct buffer_head *bh;
1787 };
1788
1789 static int
1790 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1791                       struct ext4_xattr_block_find *bs)
1792 {
1793         struct super_block *sb = inode->i_sb;
1794         int error;
1795
1796         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1797                   i->name_index, i->name, i->value, (long)i->value_len);
1798
1799         if (EXT4_I(inode)->i_file_acl) {
1800                 /* The inode already has an extended attribute block. */
1801                 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1802                 if (IS_ERR(bs->bh))
1803                         return PTR_ERR(bs->bh);
1804                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1805                         atomic_read(&(bs->bh->b_count)),
1806                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1807                 error = ext4_xattr_check_block(inode, bs->bh);
1808                 if (error)
1809                         return error;
1810                 /* Find the named attribute. */
1811                 bs->s.base = BHDR(bs->bh);
1812                 bs->s.first = BFIRST(bs->bh);
1813                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1814                 bs->s.here = bs->s.first;
1815                 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1816                                          i->name_index, i->name, 1);
1817                 if (error && error != -ENODATA)
1818                         return error;
1819                 bs->s.not_found = error;
1820         }
1821         return 0;
1822 }
1823
1824 static int
1825 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1826                      struct ext4_xattr_info *i,
1827                      struct ext4_xattr_block_find *bs)
1828 {
1829         struct super_block *sb = inode->i_sb;
1830         struct buffer_head *new_bh = NULL;
1831         struct ext4_xattr_search s_copy = bs->s;
1832         struct ext4_xattr_search *s = &s_copy;
1833         struct mb_cache_entry *ce = NULL;
1834         int error = 0;
1835         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1836         struct inode *ea_inode = NULL, *tmp_inode;
1837         size_t old_ea_inode_quota = 0;
1838         unsigned int ea_ino;
1839
1840
1841 #define header(x) ((struct ext4_xattr_header *)(x))
1842
1843         if (s->base) {
1844                 BUFFER_TRACE(bs->bh, "get_write_access");
1845                 error = ext4_journal_get_write_access(handle, bs->bh);
1846                 if (error)
1847                         goto cleanup;
1848                 lock_buffer(bs->bh);
1849
1850                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1851                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1852
1853                         /*
1854                          * This must happen under buffer lock for
1855                          * ext4_xattr_block_set() to reliably detect modified
1856                          * block
1857                          */
1858                         if (ea_block_cache)
1859                                 mb_cache_entry_delete(ea_block_cache, hash,
1860                                                       bs->bh->b_blocknr);
1861                         ea_bdebug(bs->bh, "modifying in-place");
1862                         error = ext4_xattr_set_entry(i, s, handle, inode,
1863                                                      true /* is_block */);
1864                         ext4_xattr_block_csum_set(inode, bs->bh);
1865                         unlock_buffer(bs->bh);
1866                         if (error == -EFSCORRUPTED)
1867                                 goto bad_block;
1868                         if (!error)
1869                                 error = ext4_handle_dirty_metadata(handle,
1870                                                                    inode,
1871                                                                    bs->bh);
1872                         if (error)
1873                                 goto cleanup;
1874                         goto inserted;
1875                 } else {
1876                         int offset = (char *)s->here - bs->bh->b_data;
1877
1878                         unlock_buffer(bs->bh);
1879                         ea_bdebug(bs->bh, "cloning");
1880                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1881                         error = -ENOMEM;
1882                         if (s->base == NULL)
1883                                 goto cleanup;
1884                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1885                         s->first = ENTRY(header(s->base)+1);
1886                         header(s->base)->h_refcount = cpu_to_le32(1);
1887                         s->here = ENTRY(s->base + offset);
1888                         s->end = s->base + bs->bh->b_size;
1889
1890                         /*
1891                          * If existing entry points to an xattr inode, we need
1892                          * to prevent ext4_xattr_set_entry() from decrementing
1893                          * ref count on it because the reference belongs to the
1894                          * original block. In this case, make the entry look
1895                          * like it has an empty value.
1896                          */
1897                         if (!s->not_found && s->here->e_value_inum) {
1898                                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1899                                 error = ext4_xattr_inode_iget(inode, ea_ino,
1900                                               le32_to_cpu(s->here->e_hash),
1901                                               &tmp_inode);
1902                                 if (error)
1903                                         goto cleanup;
1904
1905                                 if (!ext4_test_inode_state(tmp_inode,
1906                                                 EXT4_STATE_LUSTRE_EA_INODE)) {
1907                                         /*
1908                                          * Defer quota free call for previous
1909                                          * inode until success is guaranteed.
1910                                          */
1911                                         old_ea_inode_quota = le32_to_cpu(
1912                                                         s->here->e_value_size);
1913                                 }
1914                                 iput(tmp_inode);
1915
1916                                 s->here->e_value_inum = 0;
1917                                 s->here->e_value_size = 0;
1918                         }
1919                 }
1920         } else {
1921                 /* Allocate a buffer where we construct the new block. */
1922                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1923                 /* assert(header == s->base) */
1924                 error = -ENOMEM;
1925                 if (s->base == NULL)
1926                         goto cleanup;
1927                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1928                 header(s->base)->h_blocks = cpu_to_le32(1);
1929                 header(s->base)->h_refcount = cpu_to_le32(1);
1930                 s->first = ENTRY(header(s->base)+1);
1931                 s->here = ENTRY(header(s->base)+1);
1932                 s->end = s->base + sb->s_blocksize;
1933         }
1934
1935         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1936         if (error == -EFSCORRUPTED)
1937                 goto bad_block;
1938         if (error)
1939                 goto cleanup;
1940
1941         if (i->value && s->here->e_value_inum) {
1942                 /*
1943                  * A ref count on ea_inode has been taken as part of the call to
1944                  * ext4_xattr_set_entry() above. We would like to drop this
1945                  * extra ref but we have to wait until the xattr block is
1946                  * initialized and has its own ref count on the ea_inode.
1947                  */
1948                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1949                 error = ext4_xattr_inode_iget(inode, ea_ino,
1950                                               le32_to_cpu(s->here->e_hash),
1951                                               &ea_inode);
1952                 if (error) {
1953                         ea_inode = NULL;
1954                         goto cleanup;
1955                 }
1956         }
1957
1958 inserted:
1959         if (!IS_LAST_ENTRY(s->first)) {
1960                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1961                                                      &ce);
1962                 if (new_bh) {
1963                         /* We found an identical block in the cache. */
1964                         if (new_bh == bs->bh)
1965                                 ea_bdebug(new_bh, "keeping");
1966                         else {
1967                                 u32 ref;
1968
1969                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
1970
1971                                 /* The old block is released after updating
1972                                    the inode. */
1973                                 error = dquot_alloc_block(inode,
1974                                                 EXT4_C2B(EXT4_SB(sb), 1));
1975                                 if (error)
1976                                         goto cleanup;
1977                                 BUFFER_TRACE(new_bh, "get_write_access");
1978                                 error = ext4_journal_get_write_access(handle,
1979                                                                       new_bh);
1980                                 if (error)
1981                                         goto cleanup_dquot;
1982                                 lock_buffer(new_bh);
1983                                 /*
1984                                  * We have to be careful about races with
1985                                  * freeing, rehashing or adding references to
1986                                  * xattr block. Once we hold buffer lock xattr
1987                                  * block's state is stable so we can check
1988                                  * whether the block got freed / rehashed or
1989                                  * not.  Since we unhash mbcache entry under
1990                                  * buffer lock when freeing / rehashing xattr
1991                                  * block, checking whether entry is still
1992                                  * hashed is reliable. Same rules hold for
1993                                  * e_reusable handling.
1994                                  */
1995                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
1996                                     !ce->e_reusable) {
1997                                         /*
1998                                          * Undo everything and check mbcache
1999                                          * again.
2000                                          */
2001                                         unlock_buffer(new_bh);
2002                                         dquot_free_block(inode,
2003                                                          EXT4_C2B(EXT4_SB(sb),
2004                                                                   1));
2005                                         brelse(new_bh);
2006                                         mb_cache_entry_put(ea_block_cache, ce);
2007                                         ce = NULL;
2008                                         new_bh = NULL;
2009                                         goto inserted;
2010                                 }
2011                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2012                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2013                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2014                                         ce->e_reusable = 0;
2015                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2016                                           ref);
2017                                 ext4_xattr_block_csum_set(inode, new_bh);
2018                                 unlock_buffer(new_bh);
2019                                 error = ext4_handle_dirty_metadata(handle,
2020                                                                    inode,
2021                                                                    new_bh);
2022                                 if (error)
2023                                         goto cleanup_dquot;
2024                         }
2025                         mb_cache_entry_touch(ea_block_cache, ce);
2026                         mb_cache_entry_put(ea_block_cache, ce);
2027                         ce = NULL;
2028                 } else if (bs->bh && s->base == bs->bh->b_data) {
2029                         /* We were modifying this block in-place. */
2030                         ea_bdebug(bs->bh, "keeping this block");
2031                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2032                         new_bh = bs->bh;
2033                         get_bh(new_bh);
2034                 } else {
2035                         /* We need to allocate a new block */
2036                         ext4_fsblk_t goal, block;
2037
2038                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2039
2040                         goal = ext4_group_first_block_no(sb,
2041                                                 EXT4_I(inode)->i_block_group);
2042
2043                         /* non-extent files can't have physical blocks past 2^32 */
2044                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2045                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2046
2047                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2048                                                      NULL, &error);
2049                         if (error)
2050                                 goto cleanup;
2051
2052                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2053                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2054
2055                         ea_idebug(inode, "creating block %llu",
2056                                   (unsigned long long)block);
2057
2058                         new_bh = sb_getblk(sb, block);
2059                         if (unlikely(!new_bh)) {
2060                                 error = -ENOMEM;
2061 getblk_failed:
2062                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2063                                                  EXT4_FREE_BLOCKS_METADATA);
2064                                 goto cleanup;
2065                         }
2066                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2067                                                       ENTRY(header(s->base)+1));
2068                         if (error)
2069                                 goto getblk_failed;
2070                         if (ea_inode) {
2071                                 /* Drop the extra ref on ea_inode. */
2072                                 error = ext4_xattr_inode_dec_ref(handle,
2073                                                                  ea_inode);
2074                                 if (error)
2075                                         ext4_warning_inode(ea_inode,
2076                                                            "dec ref error=%d",
2077                                                            error);
2078                                 iput(ea_inode);
2079                                 ea_inode = NULL;
2080                         }
2081
2082                         lock_buffer(new_bh);
2083                         error = ext4_journal_get_create_access(handle, new_bh);
2084                         if (error) {
2085                                 unlock_buffer(new_bh);
2086                                 error = -EIO;
2087                                 goto getblk_failed;
2088                         }
2089                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2090                         ext4_xattr_block_csum_set(inode, new_bh);
2091                         set_buffer_uptodate(new_bh);
2092                         unlock_buffer(new_bh);
2093                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2094                         error = ext4_handle_dirty_metadata(handle, inode,
2095                                                            new_bh);
2096                         if (error)
2097                                 goto cleanup;
2098                 }
2099         }
2100
2101         if (old_ea_inode_quota)
2102                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2103
2104         /* Update the inode. */
2105         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2106
2107         /* Drop the previous xattr block. */
2108         if (bs->bh && bs->bh != new_bh) {
2109                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2110
2111                 ext4_xattr_release_block(handle, inode, bs->bh,
2112                                          &ea_inode_array,
2113                                          0 /* extra_credits */);
2114                 ext4_xattr_inode_array_free(ea_inode_array);
2115         }
2116         error = 0;
2117
2118 cleanup:
2119         if (ea_inode) {
2120                 int error2;
2121
2122                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2123                 if (error2)
2124                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2125                                            error2);
2126
2127                 /* If there was an error, revert the quota charge. */
2128                 if (error)
2129                         ext4_xattr_inode_free_quota(inode, ea_inode,
2130                                                     i_size_read(ea_inode));
2131                 iput(ea_inode);
2132         }
2133         if (ce)
2134                 mb_cache_entry_put(ea_block_cache, ce);
2135         brelse(new_bh);
2136         if (!(bs->bh && s->base == bs->bh->b_data))
2137                 kfree(s->base);
2138
2139         return error;
2140
2141 cleanup_dquot:
2142         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2143         goto cleanup;
2144
2145 bad_block:
2146         EXT4_ERROR_INODE(inode, "bad block %llu",
2147                          EXT4_I(inode)->i_file_acl);
2148         goto cleanup;
2149
2150 #undef header
2151 }
2152
2153 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2154                           struct ext4_xattr_ibody_find *is)
2155 {
2156         struct ext4_xattr_ibody_header *header;
2157         struct ext4_inode *raw_inode;
2158         int error;
2159
2160         if (EXT4_I(inode)->i_extra_isize == 0)
2161                 return 0;
2162         raw_inode = ext4_raw_inode(&is->iloc);
2163         header = IHDR(inode, raw_inode);
2164         is->s.base = is->s.first = IFIRST(header);
2165         is->s.here = is->s.first;
2166         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2167         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2168                 error = xattr_check_inode(inode, header, is->s.end);
2169                 if (error)
2170                         return error;
2171                 /* Find the named attribute. */
2172                 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2173                                          i->name_index, i->name, 0);
2174                 if (error && error != -ENODATA)
2175                         return error;
2176                 is->s.not_found = error;
2177         }
2178         return 0;
2179 }
2180
2181 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2182                                 struct ext4_xattr_info *i,
2183                                 struct ext4_xattr_ibody_find *is)
2184 {
2185         struct ext4_xattr_ibody_header *header;
2186         struct ext4_xattr_search *s = &is->s;
2187         int error;
2188
2189         if (EXT4_I(inode)->i_extra_isize == 0)
2190                 return -ENOSPC;
2191         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2192         if (error)
2193                 return error;
2194         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2195         if (!IS_LAST_ENTRY(s->first)) {
2196                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2197                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2198         } else {
2199                 header->h_magic = cpu_to_le32(0);
2200                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2201         }
2202         return 0;
2203 }
2204
2205 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2206                                 struct ext4_xattr_info *i,
2207                                 struct ext4_xattr_ibody_find *is)
2208 {
2209         struct ext4_xattr_ibody_header *header;
2210         struct ext4_xattr_search *s = &is->s;
2211         int error;
2212
2213         if (EXT4_I(inode)->i_extra_isize == 0)
2214                 return -ENOSPC;
2215         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2216         if (error)
2217                 return error;
2218         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2219         if (!IS_LAST_ENTRY(s->first)) {
2220                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2221                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2222         } else {
2223                 header->h_magic = cpu_to_le32(0);
2224                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2225         }
2226         return 0;
2227 }
2228
2229 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2230                                  struct ext4_xattr_info *i)
2231 {
2232         void *value;
2233
2234         /* When e_value_inum is set the value is stored externally. */
2235         if (s->here->e_value_inum)
2236                 return 0;
2237         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2238                 return 0;
2239         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2240         return !memcmp(value, i->value, i->value_len);
2241 }
2242
2243 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2244 {
2245         struct buffer_head *bh;
2246         int error;
2247
2248         if (!EXT4_I(inode)->i_file_acl)
2249                 return NULL;
2250         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2251         if (IS_ERR(bh))
2252                 return bh;
2253         error = ext4_xattr_check_block(inode, bh);
2254         if (error) {
2255                 brelse(bh);
2256                 return ERR_PTR(error);
2257         }
2258         return bh;
2259 }
2260
2261 /*
2262  * ext4_xattr_set_handle()
2263  *
2264  * Create, replace or remove an extended attribute for this inode.  Value
2265  * is NULL to remove an existing extended attribute, and non-NULL to
2266  * either replace an existing extended attribute, or create a new extended
2267  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2268  * specify that an extended attribute must exist and must not exist
2269  * previous to the call, respectively.
2270  *
2271  * Returns 0, or a negative error number on failure.
2272  */
2273 int
2274 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2275                       const char *name, const void *value, size_t value_len,
2276                       int flags)
2277 {
2278         struct ext4_xattr_info i = {
2279                 .name_index = name_index,
2280                 .name = name,
2281                 .value = value,
2282                 .value_len = value_len,
2283                 .in_inode = 0,
2284         };
2285         struct ext4_xattr_ibody_find is = {
2286                 .s = { .not_found = -ENODATA, },
2287         };
2288         struct ext4_xattr_block_find bs = {
2289                 .s = { .not_found = -ENODATA, },
2290         };
2291         int no_expand;
2292         int error;
2293
2294         if (!name)
2295                 return -EINVAL;
2296         if (strlen(name) > 255)
2297                 return -ERANGE;
2298
2299         ext4_write_lock_xattr(inode, &no_expand);
2300
2301         /* Check journal credits under write lock. */
2302         if (ext4_handle_valid(handle)) {
2303                 struct buffer_head *bh;
2304                 int credits;
2305
2306                 bh = ext4_xattr_get_block(inode);
2307                 if (IS_ERR(bh)) {
2308                         error = PTR_ERR(bh);
2309                         goto cleanup;
2310                 }
2311
2312                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2313                                                    value_len,
2314                                                    flags & XATTR_CREATE);
2315                 brelse(bh);
2316
2317                 if (jbd2_handle_buffer_credits(handle) < credits) {
2318                         error = -ENOSPC;
2319                         goto cleanup;
2320                 }
2321         }
2322
2323         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2324         if (error)
2325                 goto cleanup;
2326
2327         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2328                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2329                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2330                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2331         }
2332
2333         error = ext4_xattr_ibody_find(inode, &i, &is);
2334         if (error)
2335                 goto cleanup;
2336         if (is.s.not_found)
2337                 error = ext4_xattr_block_find(inode, &i, &bs);
2338         if (error)
2339                 goto cleanup;
2340         if (is.s.not_found && bs.s.not_found) {
2341                 error = -ENODATA;
2342                 if (flags & XATTR_REPLACE)
2343                         goto cleanup;
2344                 error = 0;
2345                 if (!value)
2346                         goto cleanup;
2347         } else {
2348                 error = -EEXIST;
2349                 if (flags & XATTR_CREATE)
2350                         goto cleanup;
2351         }
2352
2353         if (!value) {
2354                 if (!is.s.not_found)
2355                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2356                 else if (!bs.s.not_found)
2357                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2358         } else {
2359                 error = 0;
2360                 /* Xattr value did not change? Save us some work and bail out */
2361                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2362                         goto cleanup;
2363                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2364                         goto cleanup;
2365
2366                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2367                     (EXT4_XATTR_SIZE(i.value_len) >
2368                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2369                         i.in_inode = 1;
2370 retry_inode:
2371                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2372                 if (!error && !bs.s.not_found) {
2373                         i.value = NULL;
2374                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2375                 } else if (error == -ENOSPC) {
2376                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2377                                 brelse(bs.bh);
2378                                 bs.bh = NULL;
2379                                 error = ext4_xattr_block_find(inode, &i, &bs);
2380                                 if (error)
2381                                         goto cleanup;
2382                         }
2383                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2384                         if (!error && !is.s.not_found) {
2385                                 i.value = NULL;
2386                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2387                                                              &is);
2388                         } else if (error == -ENOSPC) {
2389                                 /*
2390                                  * Xattr does not fit in the block, store at
2391                                  * external inode if possible.
2392                                  */
2393                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2394                                     !i.in_inode) {
2395                                         i.in_inode = 1;
2396                                         goto retry_inode;
2397                                 }
2398                         }
2399                 }
2400         }
2401         if (!error) {
2402                 ext4_xattr_update_super_block(handle, inode->i_sb);
2403                 inode->i_ctime = current_time(inode);
2404                 if (!value)
2405                         no_expand = 0;
2406                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2407                 /*
2408                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2409                  * error != 0.
2410                  */
2411                 is.iloc.bh = NULL;
2412                 if (IS_SYNC(inode))
2413                         ext4_handle_sync(handle);
2414         }
2415
2416 cleanup:
2417         brelse(is.iloc.bh);
2418         brelse(bs.bh);
2419         ext4_write_unlock_xattr(inode, &no_expand);
2420         return error;
2421 }
2422
2423 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2424                            bool is_create, int *credits)
2425 {
2426         struct buffer_head *bh;
2427         int err;
2428
2429         *credits = 0;
2430
2431         if (!EXT4_SB(inode->i_sb)->s_journal)
2432                 return 0;
2433
2434         down_read(&EXT4_I(inode)->xattr_sem);
2435
2436         bh = ext4_xattr_get_block(inode);
2437         if (IS_ERR(bh)) {
2438                 err = PTR_ERR(bh);
2439         } else {
2440                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2441                                                     value_len, is_create);
2442                 brelse(bh);
2443                 err = 0;
2444         }
2445
2446         up_read(&EXT4_I(inode)->xattr_sem);
2447         return err;
2448 }
2449
2450 /*
2451  * ext4_xattr_set()
2452  *
2453  * Like ext4_xattr_set_handle, but start from an inode. This extended
2454  * attribute modification is a filesystem transaction by itself.
2455  *
2456  * Returns 0, or a negative error number on failure.
2457  */
2458 int
2459 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2460                const void *value, size_t value_len, int flags)
2461 {
2462         handle_t *handle;
2463         struct super_block *sb = inode->i_sb;
2464         int error, retries = 0;
2465         int credits;
2466
2467         error = dquot_initialize(inode);
2468         if (error)
2469                 return error;
2470
2471 retry:
2472         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2473                                        &credits);
2474         if (error)
2475                 return error;
2476
2477         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2478         if (IS_ERR(handle)) {
2479                 error = PTR_ERR(handle);
2480         } else {
2481                 int error2;
2482
2483                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2484                                               value, value_len, flags);
2485                 error2 = ext4_journal_stop(handle);
2486                 if (error == -ENOSPC &&
2487                     ext4_should_retry_alloc(sb, &retries))
2488                         goto retry;
2489                 if (error == 0)
2490                         error = error2;
2491         }
2492
2493         return error;
2494 }
2495
2496 /*
2497  * Shift the EA entries in the inode to create space for the increased
2498  * i_extra_isize.
2499  */
2500 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2501                                      int value_offs_shift, void *to,
2502                                      void *from, size_t n)
2503 {
2504         struct ext4_xattr_entry *last = entry;
2505         int new_offs;
2506
2507         /* We always shift xattr headers further thus offsets get lower */
2508         BUG_ON(value_offs_shift > 0);
2509
2510         /* Adjust the value offsets of the entries */
2511         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2512                 if (!last->e_value_inum && last->e_value_size) {
2513                         new_offs = le16_to_cpu(last->e_value_offs) +
2514                                                         value_offs_shift;
2515                         last->e_value_offs = cpu_to_le16(new_offs);
2516                 }
2517         }
2518         /* Shift the entries by n bytes */
2519         memmove(to, from, n);
2520 }
2521
2522 /*
2523  * Move xattr pointed to by 'entry' from inode into external xattr block
2524  */
2525 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2526                                     struct ext4_inode *raw_inode,
2527                                     struct ext4_xattr_entry *entry)
2528 {
2529         struct ext4_xattr_ibody_find *is = NULL;
2530         struct ext4_xattr_block_find *bs = NULL;
2531         char *buffer = NULL, *b_entry_name = NULL;
2532         size_t value_size = le32_to_cpu(entry->e_value_size);
2533         struct ext4_xattr_info i = {
2534                 .value = NULL,
2535                 .value_len = 0,
2536                 .name_index = entry->e_name_index,
2537                 .in_inode = !!entry->e_value_inum,
2538         };
2539         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2540         int error;
2541
2542         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2543         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2544         buffer = kmalloc(value_size, GFP_NOFS);
2545         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2546         if (!is || !bs || !buffer || !b_entry_name) {
2547                 error = -ENOMEM;
2548                 goto out;
2549         }
2550
2551         is->s.not_found = -ENODATA;
2552         bs->s.not_found = -ENODATA;
2553         is->iloc.bh = NULL;
2554         bs->bh = NULL;
2555
2556         /* Save the entry name and the entry value */
2557         if (entry->e_value_inum) {
2558                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2559                 if (error)
2560                         goto out;
2561         } else {
2562                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2563                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2564         }
2565
2566         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2567         b_entry_name[entry->e_name_len] = '\0';
2568         i.name = b_entry_name;
2569
2570         error = ext4_get_inode_loc(inode, &is->iloc);
2571         if (error)
2572                 goto out;
2573
2574         error = ext4_xattr_ibody_find(inode, &i, is);
2575         if (error)
2576                 goto out;
2577
2578         /* Remove the chosen entry from the inode */
2579         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2580         if (error)
2581                 goto out;
2582
2583         i.value = buffer;
2584         i.value_len = value_size;
2585         error = ext4_xattr_block_find(inode, &i, bs);
2586         if (error)
2587                 goto out;
2588
2589         /* Add entry which was removed from the inode into the block */
2590         error = ext4_xattr_block_set(handle, inode, &i, bs);
2591         if (error)
2592                 goto out;
2593         error = 0;
2594 out:
2595         kfree(b_entry_name);
2596         kfree(buffer);
2597         if (is)
2598                 brelse(is->iloc.bh);
2599         if (bs)
2600                 brelse(bs->bh);
2601         kfree(is);
2602         kfree(bs);
2603
2604         return error;
2605 }
2606
2607 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2608                                        struct ext4_inode *raw_inode,
2609                                        int isize_diff, size_t ifree,
2610                                        size_t bfree, int *total_ino)
2611 {
2612         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2613         struct ext4_xattr_entry *small_entry;
2614         struct ext4_xattr_entry *entry;
2615         struct ext4_xattr_entry *last;
2616         unsigned int entry_size;        /* EA entry size */
2617         unsigned int total_size;        /* EA entry size + value size */
2618         unsigned int min_total_size;
2619         int error;
2620
2621         while (isize_diff > ifree) {
2622                 entry = NULL;
2623                 small_entry = NULL;
2624                 min_total_size = ~0U;
2625                 last = IFIRST(header);
2626                 /* Find the entry best suited to be pushed into EA block */
2627                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2628                         /* never move system.data out of the inode */
2629                         if ((last->e_name_len == 4) &&
2630                             (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2631                             !memcmp(last->e_name, "data", 4))
2632                                 continue;
2633                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2634                         if (!last->e_value_inum)
2635                                 total_size += EXT4_XATTR_SIZE(
2636                                                le32_to_cpu(last->e_value_size));
2637                         if (total_size <= bfree &&
2638                             total_size < min_total_size) {
2639                                 if (total_size + ifree < isize_diff) {
2640                                         small_entry = last;
2641                                 } else {
2642                                         entry = last;
2643                                         min_total_size = total_size;
2644                                 }
2645                         }
2646                 }
2647
2648                 if (entry == NULL) {
2649                         if (small_entry == NULL)
2650                                 return -ENOSPC;
2651                         entry = small_entry;
2652                 }
2653
2654                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2655                 total_size = entry_size;
2656                 if (!entry->e_value_inum)
2657                         total_size += EXT4_XATTR_SIZE(
2658                                               le32_to_cpu(entry->e_value_size));
2659                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2660                                                  entry);
2661                 if (error)
2662                         return error;
2663
2664                 *total_ino -= entry_size;
2665                 ifree += total_size;
2666                 bfree -= total_size;
2667         }
2668
2669         return 0;
2670 }
2671
2672 /*
2673  * Expand an inode by new_extra_isize bytes when EAs are present.
2674  * Returns 0 on success or negative error number on failure.
2675  */
2676 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2677                                struct ext4_inode *raw_inode, handle_t *handle)
2678 {
2679         struct ext4_xattr_ibody_header *header;
2680         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2681         static unsigned int mnt_count;
2682         size_t min_offs;
2683         size_t ifree, bfree;
2684         int total_ino;
2685         void *base, *end;
2686         int error = 0, tried_min_extra_isize = 0;
2687         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2688         int isize_diff; /* How much do we need to grow i_extra_isize */
2689
2690 retry:
2691         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2692         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2693                 return 0;
2694
2695         header = IHDR(inode, raw_inode);
2696
2697         /*
2698          * Check if enough free space is available in the inode to shift the
2699          * entries ahead by new_extra_isize.
2700          */
2701
2702         base = IFIRST(header);
2703         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2704         min_offs = end - base;
2705         total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2706
2707         error = xattr_check_inode(inode, header, end);
2708         if (error)
2709                 goto cleanup;
2710
2711         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2712         if (ifree >= isize_diff)
2713                 goto shift;
2714
2715         /*
2716          * Enough free space isn't available in the inode, check if
2717          * EA block can hold new_extra_isize bytes.
2718          */
2719         if (EXT4_I(inode)->i_file_acl) {
2720                 struct buffer_head *bh;
2721
2722                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2723                 if (IS_ERR(bh)) {
2724                         error = PTR_ERR(bh);
2725                         goto cleanup;
2726                 }
2727                 error = ext4_xattr_check_block(inode, bh);
2728                 if (error) {
2729                         brelse(bh);
2730                         goto cleanup;
2731                 }
2732                 base = BHDR(bh);
2733                 end = bh->b_data + bh->b_size;
2734                 min_offs = end - base;
2735                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2736                                               NULL);
2737                 brelse(bh);
2738                 if (bfree + ifree < isize_diff) {
2739                         if (!tried_min_extra_isize && s_min_extra_isize) {
2740                                 tried_min_extra_isize++;
2741                                 new_extra_isize = s_min_extra_isize;
2742                                 goto retry;
2743                         }
2744                         error = -ENOSPC;
2745                         goto cleanup;
2746                 }
2747         } else {
2748                 bfree = inode->i_sb->s_blocksize;
2749         }
2750
2751         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2752                                             isize_diff, ifree, bfree,
2753                                             &total_ino);
2754         if (error) {
2755                 if (error == -ENOSPC && !tried_min_extra_isize &&
2756                     s_min_extra_isize) {
2757                         tried_min_extra_isize++;
2758                         new_extra_isize = s_min_extra_isize;
2759                         goto retry;
2760                 }
2761                 goto cleanup;
2762         }
2763 shift:
2764         /* Adjust the offsets and shift the remaining entries ahead */
2765         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2766                         - new_extra_isize, (void *)raw_inode +
2767                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2768                         (void *)header, total_ino);
2769         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2770
2771 cleanup:
2772         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2773                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2774                              inode->i_ino);
2775                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2776         }
2777         return error;
2778 }
2779
2780 #define EIA_INCR 16 /* must be 2^n */
2781 #define EIA_MASK (EIA_INCR - 1)
2782
2783 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2784  * If @ea_inode_array is new or full it will be grown and the old
2785  * contents copied over.
2786  */
2787 static int
2788 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2789                         struct inode *inode)
2790 {
2791         if (*ea_inode_array == NULL) {
2792                 /*
2793                  * Start with 15 inodes, so it fits into a power-of-two size.
2794                  * If *ea_inode_array is NULL, this is essentially offsetof()
2795                  */
2796                 (*ea_inode_array) =
2797                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2798                                          inodes[EIA_MASK]),
2799                                 GFP_NOFS);
2800                 if (*ea_inode_array == NULL)
2801                         return -ENOMEM;
2802                 (*ea_inode_array)->count = 0;
2803         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2804                 /* expand the array once all 15 + n * 16 slots are full */
2805                 struct ext4_xattr_inode_array *new_array = NULL;
2806                 int count = (*ea_inode_array)->count;
2807
2808                 /* if new_array is NULL, this is essentially offsetof() */
2809                 new_array = kmalloc(
2810                                 offsetof(struct ext4_xattr_inode_array,
2811                                          inodes[count + EIA_INCR]),
2812                                 GFP_NOFS);
2813                 if (new_array == NULL)
2814                         return -ENOMEM;
2815                 memcpy(new_array, *ea_inode_array,
2816                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2817                 kfree(*ea_inode_array);
2818                 *ea_inode_array = new_array;
2819         }
2820         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2821         return 0;
2822 }
2823
2824 /*
2825  * ext4_xattr_delete_inode()
2826  *
2827  * Free extended attribute resources associated with this inode. Traverse
2828  * all entries and decrement reference on any xattr inodes associated with this
2829  * inode. This is called immediately before an inode is freed. We have exclusive
2830  * access to the inode. If an orphan inode is deleted it will also release its
2831  * references on xattr block and xattr inodes.
2832  */
2833 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2834                             struct ext4_xattr_inode_array **ea_inode_array,
2835                             int extra_credits)
2836 {
2837         struct buffer_head *bh = NULL;
2838         struct ext4_xattr_ibody_header *header;
2839         struct ext4_iloc iloc = { .bh = NULL };
2840         struct ext4_xattr_entry *entry;
2841         struct inode *ea_inode;
2842         int error;
2843
2844         error = ext4_journal_ensure_credits(handle, extra_credits);
2845         if (error < 0) {
2846                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2847                 goto cleanup;
2848         }
2849
2850         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2851             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2852
2853                 error = ext4_get_inode_loc(inode, &iloc);
2854                 if (error) {
2855                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2856                         goto cleanup;
2857                 }
2858
2859                 error = ext4_journal_get_write_access(handle, iloc.bh);
2860                 if (error) {
2861                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2862                                          error);
2863                         goto cleanup;
2864                 }
2865
2866                 header = IHDR(inode, ext4_raw_inode(&iloc));
2867                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2868                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2869                                                      IFIRST(header),
2870                                                      false /* block_csum */,
2871                                                      ea_inode_array,
2872                                                      extra_credits,
2873                                                      false /* skip_quota */);
2874         }
2875
2876         if (EXT4_I(inode)->i_file_acl) {
2877                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2878                 if (IS_ERR(bh)) {
2879                         error = PTR_ERR(bh);
2880                         if (error == -EIO)
2881                                 EXT4_ERROR_INODE(inode, "block %llu read error",
2882                                                  EXT4_I(inode)->i_file_acl);
2883                         bh = NULL;
2884                         goto cleanup;
2885                 }
2886                 error = ext4_xattr_check_block(inode, bh);
2887                 if (error)
2888                         goto cleanup;
2889
2890                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2891                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2892                              entry = EXT4_XATTR_NEXT(entry)) {
2893                                 if (!entry->e_value_inum)
2894                                         continue;
2895                                 error = ext4_xattr_inode_iget(inode,
2896                                               le32_to_cpu(entry->e_value_inum),
2897                                               le32_to_cpu(entry->e_hash),
2898                                               &ea_inode);
2899                                 if (error)
2900                                         continue;
2901                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2902                                               le32_to_cpu(entry->e_value_size));
2903                                 iput(ea_inode);
2904                         }
2905
2906                 }
2907
2908                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2909                                          extra_credits);
2910                 /*
2911                  * Update i_file_acl value in the same transaction that releases
2912                  * block.
2913                  */
2914                 EXT4_I(inode)->i_file_acl = 0;
2915                 error = ext4_mark_inode_dirty(handle, inode);
2916                 if (error) {
2917                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2918                                          error);
2919                         goto cleanup;
2920                 }
2921         }
2922         error = 0;
2923 cleanup:
2924         brelse(iloc.bh);
2925         brelse(bh);
2926         return error;
2927 }
2928
2929 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2930 {
2931         int idx;
2932
2933         if (ea_inode_array == NULL)
2934                 return;
2935
2936         for (idx = 0; idx < ea_inode_array->count; ++idx)
2937                 iput(ea_inode_array->inodes[idx]);
2938         kfree(ea_inode_array);
2939 }
2940
2941 /*
2942  * ext4_xattr_block_cache_insert()
2943  *
2944  * Create a new entry in the extended attribute block cache, and insert
2945  * it unless such an entry is already in the cache.
2946  *
2947  * Returns 0, or a negative error number on failure.
2948  */
2949 static void
2950 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2951                               struct buffer_head *bh)
2952 {
2953         struct ext4_xattr_header *header = BHDR(bh);
2954         __u32 hash = le32_to_cpu(header->h_hash);
2955         int reusable = le32_to_cpu(header->h_refcount) <
2956                        EXT4_XATTR_REFCOUNT_MAX;
2957         int error;
2958
2959         if (!ea_block_cache)
2960                 return;
2961         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2962                                       bh->b_blocknr, reusable);
2963         if (error) {
2964                 if (error == -EBUSY)
2965                         ea_bdebug(bh, "already in cache");
2966         } else
2967                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2968 }
2969
2970 /*
2971  * ext4_xattr_cmp()
2972  *
2973  * Compare two extended attribute blocks for equality.
2974  *
2975  * Returns 0 if the blocks are equal, 1 if they differ, and
2976  * a negative error number on errors.
2977  */
2978 static int
2979 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2980                struct ext4_xattr_header *header2)
2981 {
2982         struct ext4_xattr_entry *entry1, *entry2;
2983
2984         entry1 = ENTRY(header1+1);
2985         entry2 = ENTRY(header2+1);
2986         while (!IS_LAST_ENTRY(entry1)) {
2987                 if (IS_LAST_ENTRY(entry2))
2988                         return 1;
2989                 if (entry1->e_hash != entry2->e_hash ||
2990                     entry1->e_name_index != entry2->e_name_index ||
2991                     entry1->e_name_len != entry2->e_name_len ||
2992                     entry1->e_value_size != entry2->e_value_size ||
2993                     entry1->e_value_inum != entry2->e_value_inum ||
2994                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2995                         return 1;
2996                 if (!entry1->e_value_inum &&
2997                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
2998                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
2999                            le32_to_cpu(entry1->e_value_size)))
3000                         return 1;
3001
3002                 entry1 = EXT4_XATTR_NEXT(entry1);
3003                 entry2 = EXT4_XATTR_NEXT(entry2);
3004         }
3005         if (!IS_LAST_ENTRY(entry2))
3006                 return 1;
3007         return 0;
3008 }
3009
3010 /*
3011  * ext4_xattr_block_cache_find()
3012  *
3013  * Find an identical extended attribute block.
3014  *
3015  * Returns a pointer to the block found, or NULL if such a block was
3016  * not found or an error occurred.
3017  */
3018 static struct buffer_head *
3019 ext4_xattr_block_cache_find(struct inode *inode,
3020                             struct ext4_xattr_header *header,
3021                             struct mb_cache_entry **pce)
3022 {
3023         __u32 hash = le32_to_cpu(header->h_hash);
3024         struct mb_cache_entry *ce;
3025         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3026
3027         if (!ea_block_cache)
3028                 return NULL;
3029         if (!header->h_hash)
3030                 return NULL;  /* never share */
3031         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3032         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3033         while (ce) {
3034                 struct buffer_head *bh;
3035
3036                 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3037                 if (IS_ERR(bh)) {
3038                         if (PTR_ERR(bh) == -ENOMEM)
3039                                 return NULL;
3040                         bh = NULL;
3041                         EXT4_ERROR_INODE(inode, "block %lu read error",
3042                                          (unsigned long)ce->e_value);
3043                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3044                         *pce = ce;
3045                         return bh;
3046                 }
3047                 brelse(bh);
3048                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3049         }
3050         return NULL;
3051 }
3052
3053 #define NAME_HASH_SHIFT 5
3054 #define VALUE_HASH_SHIFT 16
3055
3056 /*
3057  * ext4_xattr_hash_entry()
3058  *
3059  * Compute the hash of an extended attribute.
3060  */
3061 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3062                                     size_t value_count)
3063 {
3064         __u32 hash = 0;
3065
3066         while (name_len--) {
3067                 hash = (hash << NAME_HASH_SHIFT) ^
3068                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3069                        *name++;
3070         }
3071         while (value_count--) {
3072                 hash = (hash << VALUE_HASH_SHIFT) ^
3073                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3074                        le32_to_cpu(*value++);
3075         }
3076         return cpu_to_le32(hash);
3077 }
3078
3079 #undef NAME_HASH_SHIFT
3080 #undef VALUE_HASH_SHIFT
3081
3082 #define BLOCK_HASH_SHIFT 16
3083
3084 /*
3085  * ext4_xattr_rehash()
3086  *
3087  * Re-compute the extended attribute hash value after an entry has changed.
3088  */
3089 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3090 {
3091         struct ext4_xattr_entry *here;
3092         __u32 hash = 0;
3093
3094         here = ENTRY(header+1);
3095         while (!IS_LAST_ENTRY(here)) {
3096                 if (!here->e_hash) {
3097                         /* Block is not shared if an entry's hash value == 0 */
3098                         hash = 0;
3099                         break;
3100                 }
3101                 hash = (hash << BLOCK_HASH_SHIFT) ^
3102                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3103                        le32_to_cpu(here->e_hash);
3104                 here = EXT4_XATTR_NEXT(here);
3105         }
3106         header->h_hash = cpu_to_le32(hash);
3107 }
3108
3109 #undef BLOCK_HASH_SHIFT
3110
3111 #define HASH_BUCKET_BITS        10
3112
3113 struct mb_cache *
3114 ext4_xattr_create_cache(void)
3115 {
3116         return mb_cache_create(HASH_BUCKET_BITS);
3117 }
3118
3119 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3120 {
3121         if (cache)
3122                 mb_cache_destroy(cache);
3123 }
3124