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         [EXT4_XATTR_INDEX_HURD]              = &ext4_xattr_hurd_handler,
  97 };
  98
  99 const struct xattr_handler *ext4_xattr_handlers[] = {
 100         &ext4_xattr_user_handler,
 101         &ext4_xattr_trusted_handler,
 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 103         &posix_acl_access_xattr_handler,
 104         &posix_acl_default_xattr_handler,
 105 #endif
 106 #ifdef CONFIG_EXT4_FS_SECURITY
 107         &ext4_xattr_security_handler,
 108 #endif
 109         &ext4_xattr_hurd_handler,
 110         NULL
 111 };
 112
 113 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 114                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 115
 116 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 117                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 118
 119 static int
 120 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 121                         struct inode *inode);
 122
 123 #ifdef CONFIG_LOCKDEP
 124 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 125 {
 126         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 127 }
 128 #endif
 129
 130 static __le32 ext4_xattr_block_csum(struct inode *inode,
 131                                     sector_t block_nr,
 132                                     struct ext4_xattr_header *hdr)
 133 {
 134         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 135         __u32 csum;
 136         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 137         __u32 dummy_csum = 0;
 138         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 139
 140         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 141                            sizeof(dsk_block_nr));
 142         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 143         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 144         offset += sizeof(dummy_csum);
 145         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 146                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 147
 148         return cpu_to_le32(csum);
 149 }
 150
 151 static int ext4_xattr_block_csum_verify(struct inode *inode,
 152                                         struct buffer_head *bh)
 153 {
 154         struct ext4_xattr_header *hdr = BHDR(bh);
 155         int ret = 1;
 156
 157         if (ext4_has_metadata_csum(inode->i_sb)) {
 158                 lock_buffer(bh);
 159                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 160                                                         bh->b_blocknr, hdr));
 161                 unlock_buffer(bh);
 162         }
 163         return ret;
 164 }
 165
 166 static void ext4_xattr_block_csum_set(struct inode *inode,
 167                                       struct buffer_head *bh)
 168 {
 169         if (ext4_has_metadata_csum(inode->i_sb))
 170                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 171                                                 bh->b_blocknr, BHDR(bh));
 172 }
 173
 174 static inline const struct xattr_handler *
 175 ext4_xattr_handler(int name_index)
 176 {
 177         const struct xattr_handler *handler = NULL;
 178
 179         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 180                 handler = ext4_xattr_handler_map[name_index];
 181         return handler;
 182 }
 183
 184 static int
 185 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
 186                          void *value_start)
 187 {
 188         struct ext4_xattr_entry *e = entry;
 189
 190         /* Find the end of the names list */
 191         while (!IS_LAST_ENTRY(e)) {
 192                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 193                 if ((void *)next >= end)
 194                         return -EFSCORRUPTED;
 195                 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
 196                         return -EFSCORRUPTED;
 197                 e = next;
 198         }
 199
 200         /* Check the values */
 201         while (!IS_LAST_ENTRY(entry)) {
 202                 u32 size = le32_to_cpu(entry->e_value_size);
 203
 204                 if (size > EXT4_XATTR_SIZE_MAX)
 205                         return -EFSCORRUPTED;
 206
 207                 if (size != 0 && entry->e_value_inum == 0) {
 208                         u16 offs = le16_to_cpu(entry->e_value_offs);
 209                         void *value;
 210
 211                         /*
 212                          * The value cannot overlap the names, and the value
 213                          * with padding cannot extend beyond 'end'.  Check both
 214                          * the padded and unpadded sizes, since the size may
 215                          * overflow to 0 when adding padding.
 216                          */
 217                         if (offs > end - value_start)
 218                                 return -EFSCORRUPTED;
 219                         value = value_start + offs;
 220                         if (value < (void *)e + sizeof(u32) ||
 221                             size > end - value ||
 222                             EXT4_XATTR_SIZE(size) > end - value)
 223                                 return -EFSCORRUPTED;
 224                 }
 225                 entry = EXT4_XATTR_NEXT(entry);
 226         }
 227
 228         return 0;
 229 }
 230
 231 static inline int
 232 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
 233                          const char *function, unsigned int line)
 234 {
 235         int error = -EFSCORRUPTED;
 236
 237         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 238             BHDR(bh)->h_blocks != cpu_to_le32(1))
 239                 goto errout;
 240         if (buffer_verified(bh))
 241                 return 0;
 242
 243         error = -EFSBADCRC;
 244         if (!ext4_xattr_block_csum_verify(inode, bh))
 245                 goto errout;
 246         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 247                                          bh->b_data);
 248 errout:
 249         if (error)
 250                 __ext4_error_inode(inode, function, line, 0, -error,
 251                                    "corrupted xattr block %llu",
 252                                    (unsigned long long) bh->b_blocknr);
 253         else
 254                 set_buffer_verified(bh);
 255         return error;
 256 }
 257
 258 #define ext4_xattr_check_block(inode, bh) \
 259         __ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
 260
 261
 262 static int
 263 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 264                          void *end, const char *function, unsigned int line)
 265 {
 266         int error = -EFSCORRUPTED;
 267
 268         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 269             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 270                 goto errout;
 271         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 272 errout:
 273         if (error)
 274                 __ext4_error_inode(inode, function, line, 0, -error,
 275                                    "corrupted in-inode xattr");
 276         return error;
 277 }
 278
 279 #define xattr_check_inode(inode, header, end) \
 280         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 281
 282 static int
 283 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
 284                  void *end, int name_index, const char *name, int sorted)
 285 {
 286         struct ext4_xattr_entry *entry, *next;
 287         size_t name_len;
 288         int cmp = 1;
 289
 290         if (name == NULL)
 291                 return -EINVAL;
 292         name_len = strlen(name);
 293         for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
 294                 next = EXT4_XATTR_NEXT(entry);
 295                 if ((void *) next >= end) {
 296                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
 297                         return -EFSCORRUPTED;
 298                 }
 299                 cmp = name_index - entry->e_name_index;
 300                 if (!cmp)
 301                         cmp = name_len - entry->e_name_len;
 302                 if (!cmp)
 303                         cmp = memcmp(name, entry->e_name, name_len);
 304                 if (cmp <= 0 && (sorted || cmp == 0))
 305                         break;
 306         }
 307         *pentry = entry;
 308         return cmp ? -ENODATA : 0;
 309 }
 310
 311 static u32
 312 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 313 {
 314         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 315 }
 316
 317 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 318 {
 319         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 320                 (u32) inode_peek_iversion_raw(ea_inode);
 321 }
 322
 323 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 324 {
 325         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 326         inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
 327 }
 328
 329 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 330 {
 331         return (u32)ea_inode->i_atime.tv_sec;
 332 }
 333
 334 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 335 {
 336         ea_inode->i_atime.tv_sec = hash;
 337 }
 338
 339 /*
 340  * Read the EA value from an inode.
 341  */
 342 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 343 {
 344         int blocksize = 1 << ea_inode->i_blkbits;
 345         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 346         int tail_size = (size % blocksize) ?: blocksize;
 347         struct buffer_head *bhs_inline[8];
 348         struct buffer_head **bhs = bhs_inline;
 349         int i, ret;
 350
 351         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 352                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 353                 if (!bhs)
 354                         return -ENOMEM;
 355         }
 356
 357         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 358                                true /* wait */, bhs);
 359         if (ret)
 360                 goto free_bhs;
 361
 362         for (i = 0; i < bh_count; i++) {
 363                 /* There shouldn't be any holes in ea_inode. */
 364                 if (!bhs[i]) {
 365                         ret = -EFSCORRUPTED;
 366                         goto put_bhs;
 367                 }
 368                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 369                        i < bh_count - 1 ? blocksize : tail_size);
 370         }
 371         ret = 0;
 372 put_bhs:
 373         for (i = 0; i < bh_count; i++)
 374                 brelse(bhs[i]);
 375 free_bhs:
 376         if (bhs != bhs_inline)
 377                 kfree(bhs);
 378         return ret;
 379 }
 380
 381 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 382
 383 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 384                                  u32 ea_inode_hash, struct inode **ea_inode)
 385 {
 386         struct inode *inode;
 387         int err;
 388
 389         inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
 390         if (IS_ERR(inode)) {
 391                 err = PTR_ERR(inode);
 392                 ext4_error(parent->i_sb,
 393                            "error while reading EA inode %lu err=%d", ea_ino,
 394                            err);
 395                 return err;
 396         }
 397
 398         if (is_bad_inode(inode)) {
 399                 ext4_error(parent->i_sb,
 400                            "error while reading EA inode %lu is_bad_inode",
 401                            ea_ino);
 402                 err = -EIO;
 403                 goto error;
 404         }
 405
 406         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 407                 ext4_error(parent->i_sb,
 408                            "EA inode %lu does not have EXT4_EA_INODE_FL flag",
 409                             ea_ino);
 410                 err = -EINVAL;
 411                 goto error;
 412         }
 413
 414         ext4_xattr_inode_set_class(inode);
 415
 416         /*
 417          * Check whether this is an old Lustre-style xattr inode. Lustre
 418          * implementation does not have hash validation, rather it has a
 419          * backpointer from ea_inode to the parent inode.
 420          */
 421         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 422             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 423             inode->i_generation == parent->i_generation) {
 424                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 425                 ext4_xattr_inode_set_ref(inode, 1);
 426         } else {
 427                 inode_lock(inode);
 428                 inode->i_flags |= S_NOQUOTA;
 429                 inode_unlock(inode);
 430         }
 431
 432         *ea_inode = inode;
 433         return 0;
 434 error:
 435         iput(inode);
 436         return err;
 437 }
 438
 439 static int
 440 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 441                                struct ext4_xattr_entry *entry, void *buffer,
 442                                size_t size)
 443 {
 444         u32 hash;
 445
 446         /* Verify stored hash matches calculated hash. */
 447         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 448         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 449                 return -EFSCORRUPTED;
 450
 451         if (entry) {
 452                 __le32 e_hash, tmp_data;
 453
 454                 /* Verify entry hash. */
 455                 tmp_data = cpu_to_le32(hash);
 456                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 457                                                &tmp_data, 1);
 458                 if (e_hash != entry->e_hash)
 459                         return -EFSCORRUPTED;
 460         }
 461         return 0;
 462 }
 463
 464 /*
 465  * Read xattr value from the EA inode.
 466  */
 467 static int
 468 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 469                      void *buffer, size_t size)
 470 {
 471         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 472         struct inode *ea_inode;
 473         int err;
 474
 475         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 476                                     le32_to_cpu(entry->e_hash), &ea_inode);
 477         if (err) {
 478                 ea_inode = NULL;
 479                 goto out;
 480         }
 481
 482         if (i_size_read(ea_inode) != size) {
 483                 ext4_warning_inode(ea_inode,
 484                                    "ea_inode file size=%llu entry size=%zu",
 485                                    i_size_read(ea_inode), size);
 486                 err = -EFSCORRUPTED;
 487                 goto out;
 488         }
 489
 490         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 491         if (err)
 492                 goto out;
 493
 494         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 495                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 496                                                      size);
 497                 if (err) {
 498                         ext4_warning_inode(ea_inode,
 499                                            "EA inode hash validation failed");
 500                         goto out;
 501                 }
 502
 503                 if (ea_inode_cache)
 504                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 505                                         ext4_xattr_inode_get_hash(ea_inode),
 506                                         ea_inode->i_ino, true /* reusable */);
 507         }
 508 out:
 509         iput(ea_inode);
 510         return err;
 511 }
 512
 513 static int
 514 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 515                      void *buffer, size_t buffer_size)
 516 {
 517         struct buffer_head *bh = NULL;
 518         struct ext4_xattr_entry *entry;
 519         size_t size;
 520         void *end;
 521         int error;
 522         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 523
 524         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 525                   name_index, name, buffer, (long)buffer_size);
 526
 527         if (!EXT4_I(inode)->i_file_acl)
 528                 return -ENODATA;
 529         ea_idebug(inode, "reading block %llu",
 530                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 531         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 532         if (IS_ERR(bh))
 533                 return PTR_ERR(bh);
 534         ea_bdebug(bh, "b_count=%d, refcount=%d",
 535                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 536         error = ext4_xattr_check_block(inode, bh);
 537         if (error)
 538                 goto cleanup;
 539         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 540         entry = BFIRST(bh);
 541         end = bh->b_data + bh->b_size;
 542         error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
 543         if (error)
 544                 goto cleanup;
 545         size = le32_to_cpu(entry->e_value_size);
 546         error = -ERANGE;
 547         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 548                 goto cleanup;
 549         if (buffer) {
 550                 if (size > buffer_size)
 551                         goto cleanup;
 552                 if (entry->e_value_inum) {
 553                         error = ext4_xattr_inode_get(inode, entry, buffer,
 554                                                      size);
 555                         if (error)
 556                                 goto cleanup;
 557                 } else {
 558                         u16 offset = le16_to_cpu(entry->e_value_offs);
 559                         void *p = bh->b_data + offset;
 560
 561                         if (unlikely(p + size > end))
 562                                 goto cleanup;
 563                         memcpy(buffer, p, size);
 564                 }
 565         }
 566         error = size;
 567
 568 cleanup:
 569         brelse(bh);
 570         return error;
 571 }
 572
 573 int
 574 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 575                      void *buffer, size_t buffer_size)
 576 {
 577         struct ext4_xattr_ibody_header *header;
 578         struct ext4_xattr_entry *entry;
 579         struct ext4_inode *raw_inode;
 580         struct ext4_iloc iloc;
 581         size_t size;
 582         void *end;
 583         int error;
 584
 585         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 586                 return -ENODATA;
 587         error = ext4_get_inode_loc(inode, &iloc);
 588         if (error)
 589                 return error;
 590         raw_inode = ext4_raw_inode(&iloc);
 591         header = IHDR(inode, raw_inode);
 592         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 593         error = xattr_check_inode(inode, header, end);
 594         if (error)
 595                 goto cleanup;
 596         entry = IFIRST(header);
 597         error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
 598         if (error)
 599                 goto cleanup;
 600         size = le32_to_cpu(entry->e_value_size);
 601         error = -ERANGE;
 602         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 603                 goto cleanup;
 604         if (buffer) {
 605                 if (size > buffer_size)
 606                         goto cleanup;
 607                 if (entry->e_value_inum) {
 608                         error = ext4_xattr_inode_get(inode, entry, buffer,
 609                                                      size);
 610                         if (error)
 611                                 goto cleanup;
 612                 } else {
 613                         u16 offset = le16_to_cpu(entry->e_value_offs);
 614                         void *p = (void *)IFIRST(header) + offset;
 615
 616                         if (unlikely(p + size > end))
 617                                 goto cleanup;
 618                         memcpy(buffer, p, size);
 619                 }
 620         }
 621         error = size;
 622
 623 cleanup:
 624         brelse(iloc.bh);
 625         return error;
 626 }
 627
 628 /*
 629  * ext4_xattr_get()
 630  *
 631  * Copy an extended attribute into the buffer
 632  * provided, or compute the buffer size required.
 633  * Buffer is NULL to compute the size of the buffer required.
 634  *
 635  * Returns a negative error number on failure, or the number of bytes
 636  * used / required on success.
 637  */
 638 int
 639 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 640                void *buffer, size_t buffer_size)
 641 {
 642         int error;
 643
 644         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 645                 return -EIO;
 646
 647         if (strlen(name) > 255)
 648                 return -ERANGE;
 649
 650         down_read(&EXT4_I(inode)->xattr_sem);
 651         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 652                                      buffer_size);
 653         if (error == -ENODATA)
 654                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 655                                              buffer_size);
 656         up_read(&EXT4_I(inode)->xattr_sem);
 657         return error;
 658 }
 659
 660 static int
 661 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 662                         char *buffer, size_t buffer_size)
 663 {
 664         size_t rest = buffer_size;
 665
 666         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 667                 const struct xattr_handler *handler =
 668                         ext4_xattr_handler(entry->e_name_index);
 669
 670                 if (handler && (!handler->list || handler->list(dentry))) {
 671                         const char *prefix = handler->prefix ?: handler->name;
 672                         size_t prefix_len = strlen(prefix);
 673                         size_t size = prefix_len + entry->e_name_len + 1;
 674
 675                         if (buffer) {
 676                                 if (size > rest)
 677                                         return -ERANGE;
 678                                 memcpy(buffer, prefix, prefix_len);
 679                                 buffer += prefix_len;
 680                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 681                                 buffer += entry->e_name_len;
 682                                 *buffer++ = 0;
 683                         }
 684                         rest -= size;
 685                 }
 686         }
 687         return buffer_size - rest;  /* total size */
 688 }
 689
 690 static int
 691 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 692 {
 693         struct inode *inode = d_inode(dentry);
 694         struct buffer_head *bh = NULL;
 695         int error;
 696
 697         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 698                   buffer, (long)buffer_size);
 699
 700         if (!EXT4_I(inode)->i_file_acl)
 701                 return 0;
 702         ea_idebug(inode, "reading block %llu",
 703                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 704         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 705         if (IS_ERR(bh))
 706                 return PTR_ERR(bh);
 707         ea_bdebug(bh, "b_count=%d, refcount=%d",
 708                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 709         error = ext4_xattr_check_block(inode, bh);
 710         if (error)
 711                 goto cleanup;
 712         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 713         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
 714                                         buffer_size);
 715 cleanup:
 716         brelse(bh);
 717         return error;
 718 }
 719
 720 static int
 721 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 722 {
 723         struct inode *inode = d_inode(dentry);
 724         struct ext4_xattr_ibody_header *header;
 725         struct ext4_inode *raw_inode;
 726         struct ext4_iloc iloc;
 727         void *end;
 728         int error;
 729
 730         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 731                 return 0;
 732         error = ext4_get_inode_loc(inode, &iloc);
 733         if (error)
 734                 return error;
 735         raw_inode = ext4_raw_inode(&iloc);
 736         header = IHDR(inode, raw_inode);
 737         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 738         error = xattr_check_inode(inode, header, end);
 739         if (error)
 740                 goto cleanup;
 741         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 742                                         buffer, buffer_size);
 743
 744 cleanup:
 745         brelse(iloc.bh);
 746         return error;
 747 }
 748
 749 /*
 750  * Inode operation listxattr()
 751  *
 752  * d_inode(dentry)->i_rwsem: don't care
 753  *
 754  * Copy a list of attribute names into the buffer
 755  * provided, or compute the buffer size required.
 756  * Buffer is NULL to compute the size of the buffer required.
 757  *
 758  * Returns a negative error number on failure, or the number of bytes
 759  * used / required on success.
 760  */
 761 ssize_t
 762 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 763 {
 764         int ret, ret2;
 765
 766         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 767         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 768         if (ret < 0)
 769                 goto errout;
 770         if (buffer) {
 771                 buffer += ret;
 772                 buffer_size -= ret;
 773         }
 774         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 775         if (ret < 0)
 776                 goto errout;
 777         ret += ret2;
 778 errout:
 779         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 780         return ret;
 781 }
 782
 783 /*
 784  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 785  * not set, set it.
 786  */
 787 static void ext4_xattr_update_super_block(handle_t *handle,
 788                                           struct super_block *sb)
 789 {
 790         if (ext4_has_feature_xattr(sb))
 791                 return;
 792
 793         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 794         if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 795                                           EXT4_JTR_NONE) == 0) {
 796                 lock_buffer(EXT4_SB(sb)->s_sbh);
 797                 ext4_set_feature_xattr(sb);
 798                 ext4_superblock_csum_set(sb);
 799                 unlock_buffer(EXT4_SB(sb)->s_sbh);
 800                 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 801         }
 802 }
 803
 804 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 805 {
 806         struct ext4_iloc iloc = { .bh = NULL };
 807         struct buffer_head *bh = NULL;
 808         struct ext4_inode *raw_inode;
 809         struct ext4_xattr_ibody_header *header;
 810         struct ext4_xattr_entry *entry;
 811         qsize_t ea_inode_refs = 0;
 812         void *end;
 813         int ret;
 814
 815         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 816
 817         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 818                 ret = ext4_get_inode_loc(inode, &iloc);
 819                 if (ret)
 820                         goto out;
 821                 raw_inode = ext4_raw_inode(&iloc);
 822                 header = IHDR(inode, raw_inode);
 823                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 824                 ret = xattr_check_inode(inode, header, end);
 825                 if (ret)
 826                         goto out;
 827
 828                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 829                      entry = EXT4_XATTR_NEXT(entry))
 830                         if (entry->e_value_inum)
 831                                 ea_inode_refs++;
 832         }
 833
 834         if (EXT4_I(inode)->i_file_acl) {
 835                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 836                 if (IS_ERR(bh)) {
 837                         ret = PTR_ERR(bh);
 838                         bh = NULL;
 839                         goto out;
 840                 }
 841
 842                 ret = ext4_xattr_check_block(inode, bh);
 843                 if (ret)
 844                         goto out;
 845
 846                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 847                      entry = EXT4_XATTR_NEXT(entry))
 848                         if (entry->e_value_inum)
 849                                 ea_inode_refs++;
 850         }
 851         *usage = ea_inode_refs + 1;
 852         ret = 0;
 853 out:
 854         brelse(iloc.bh);
 855         brelse(bh);
 856         return ret;
 857 }
 858
 859 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 860 {
 861         struct super_block *sb = inode->i_sb;
 862         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 863                                     inode->i_blkbits);
 864         size_t mask = ~(cluster_size - 1);
 865
 866         return (length + cluster_size - 1) & mask;
 867 }
 868
 869 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 870 {
 871         int err;
 872
 873         err = dquot_alloc_inode(inode);
 874         if (err)
 875                 return err;
 876         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 877         if (err)
 878                 dquot_free_inode(inode);
 879         return err;
 880 }
 881
 882 static void ext4_xattr_inode_free_quota(struct inode *parent,
 883                                         struct inode *ea_inode,
 884                                         size_t len)
 885 {
 886         if (ea_inode &&
 887             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 888                 return;
 889         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 890         dquot_free_inode(parent);
 891 }
 892
 893 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 894                              struct buffer_head *block_bh, size_t value_len,
 895                              bool is_create)
 896 {
 897         int credits;
 898         int blocks;
 899
 900         /*
 901          * 1) Owner inode update
 902          * 2) Ref count update on old xattr block
 903          * 3) new xattr block
 904          * 4) block bitmap update for new xattr block
 905          * 5) group descriptor for new xattr block
 906          * 6) block bitmap update for old xattr block
 907          * 7) group descriptor for old block
 908          *
 909          * 6 & 7 can happen if we have two racing threads T_a and T_b
 910          * which are each trying to set an xattr on inodes I_a and I_b
 911          * which were both initially sharing an xattr block.
 912          */
 913         credits = 7;
 914
 915         /* Quota updates. */
 916         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 917
 918         /*
 919          * In case of inline data, we may push out the data to a block,
 920          * so we need to reserve credits for this eventuality
 921          */
 922         if (inode && ext4_has_inline_data(inode))
 923                 credits += ext4_writepage_trans_blocks(inode) + 1;
 924
 925         /* We are done if ea_inode feature is not enabled. */
 926         if (!ext4_has_feature_ea_inode(sb))
 927                 return credits;
 928
 929         /* New ea_inode, inode map, block bitmap, group descriptor. */
 930         credits += 4;
 931
 932         /* Data blocks. */
 933         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 934
 935         /* Indirection block or one level of extent tree. */
 936         blocks += 1;
 937
 938         /* Block bitmap and group descriptor updates for each block. */
 939         credits += blocks * 2;
 940
 941         /* Blocks themselves. */
 942         credits += blocks;
 943
 944         if (!is_create) {
 945                 /* Dereference ea_inode holding old xattr value.
 946                  * Old ea_inode, inode map, block bitmap, group descriptor.
 947                  */
 948                 credits += 4;
 949
 950                 /* Data blocks for old ea_inode. */
 951                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 952
 953                 /* Indirection block or one level of extent tree for old
 954                  * ea_inode.
 955                  */
 956                 blocks += 1;
 957
 958                 /* Block bitmap and group descriptor updates for each block. */
 959                 credits += blocks * 2;
 960         }
 961
 962         /* We may need to clone the existing xattr block in which case we need
 963          * to increment ref counts for existing ea_inodes referenced by it.
 964          */
 965         if (block_bh) {
 966                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 967
 968                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 969                         if (entry->e_value_inum)
 970                                 /* Ref count update on ea_inode. */
 971                                 credits += 1;
 972         }
 973         return credits;
 974 }
 975
 976 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 977                                        int ref_change)
 978 {
 979         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
 980         struct ext4_iloc iloc;
 981         s64 ref_count;
 982         u32 hash;
 983         int ret;
 984
 985         inode_lock(ea_inode);
 986
 987         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
 988         if (ret)
 989                 goto out;
 990
 991         ref_count = ext4_xattr_inode_get_ref(ea_inode);
 992         ref_count += ref_change;
 993         ext4_xattr_inode_set_ref(ea_inode, ref_count);
 994
 995         if (ref_change > 0) {
 996                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
 997                           ea_inode->i_ino, ref_count);
 998
 999                 if (ref_count == 1) {
1000                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1001                                   ea_inode->i_ino, ea_inode->i_nlink);
1002
1003                         set_nlink(ea_inode, 1);
1004                         ext4_orphan_del(handle, ea_inode);
1005
1006                         if (ea_inode_cache) {
1007                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1008                                 mb_cache_entry_create(ea_inode_cache,
1009                                                       GFP_NOFS, hash,
1010                                                       ea_inode->i_ino,
1011                                                       true /* reusable */);
1012                         }
1013                 }
1014         } else {
1015                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1016                           ea_inode->i_ino, ref_count);
1017
1018                 if (ref_count == 0) {
1019                         WARN_ONCE(ea_inode->i_nlink != 1,
1020                                   "EA inode %lu i_nlink=%u",
1021                                   ea_inode->i_ino, ea_inode->i_nlink);
1022
1023                         clear_nlink(ea_inode);
1024                         ext4_orphan_add(handle, ea_inode);
1025
1026                         if (ea_inode_cache) {
1027                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1028                                 mb_cache_entry_delete(ea_inode_cache, hash,
1029                                                       ea_inode->i_ino);
1030                         }
1031                 }
1032         }
1033
1034         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1035         if (ret)
1036                 ext4_warning_inode(ea_inode,
1037                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1038 out:
1039         inode_unlock(ea_inode);
1040         return ret;
1041 }
1042
1043 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1044 {
1045         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1046 }
1047
1048 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1049 {
1050         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1051 }
1052
1053 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1054                                         struct ext4_xattr_entry *first)
1055 {
1056         struct inode *ea_inode;
1057         struct ext4_xattr_entry *entry;
1058         struct ext4_xattr_entry *failed_entry;
1059         unsigned int ea_ino;
1060         int err, saved_err;
1061
1062         for (entry = first; !IS_LAST_ENTRY(entry);
1063              entry = EXT4_XATTR_NEXT(entry)) {
1064                 if (!entry->e_value_inum)
1065                         continue;
1066                 ea_ino = le32_to_cpu(entry->e_value_inum);
1067                 err = ext4_xattr_inode_iget(parent, ea_ino,
1068                                             le32_to_cpu(entry->e_hash),
1069                                             &ea_inode);
1070                 if (err)
1071                         goto cleanup;
1072                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1073                 if (err) {
1074                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1075                         iput(ea_inode);
1076                         goto cleanup;
1077                 }
1078                 iput(ea_inode);
1079         }
1080         return 0;
1081
1082 cleanup:
1083         saved_err = err;
1084         failed_entry = entry;
1085
1086         for (entry = first; entry != failed_entry;
1087              entry = EXT4_XATTR_NEXT(entry)) {
1088                 if (!entry->e_value_inum)
1089                         continue;
1090                 ea_ino = le32_to_cpu(entry->e_value_inum);
1091                 err = ext4_xattr_inode_iget(parent, ea_ino,
1092                                             le32_to_cpu(entry->e_hash),
1093                                             &ea_inode);
1094                 if (err) {
1095                         ext4_warning(parent->i_sb,
1096                                      "cleanup ea_ino %u iget error %d", ea_ino,
1097                                      err);
1098                         continue;
1099                 }
1100                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1101                 if (err)
1102                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1103                                            err);
1104                 iput(ea_inode);
1105         }
1106         return saved_err;
1107 }
1108
1109 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1110                         struct buffer_head *bh, bool block_csum, bool dirty)
1111 {
1112         int error;
1113
1114         if (bh && dirty) {
1115                 if (block_csum)
1116                         ext4_xattr_block_csum_set(inode, bh);
1117                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1118                 if (error) {
1119                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1120                                      error);
1121                         return error;
1122                 }
1123         }
1124         return 0;
1125 }
1126
1127 static void
1128 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1129                              struct buffer_head *bh,
1130                              struct ext4_xattr_entry *first, bool block_csum,
1131                              struct ext4_xattr_inode_array **ea_inode_array,
1132                              int extra_credits, bool skip_quota)
1133 {
1134         struct inode *ea_inode;
1135         struct ext4_xattr_entry *entry;
1136         bool dirty = false;
1137         unsigned int ea_ino;
1138         int err;
1139         int credits;
1140
1141         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1142         credits = 2 + extra_credits;
1143
1144         for (entry = first; !IS_LAST_ENTRY(entry);
1145              entry = EXT4_XATTR_NEXT(entry)) {
1146                 if (!entry->e_value_inum)
1147                         continue;
1148                 ea_ino = le32_to_cpu(entry->e_value_inum);
1149                 err = ext4_xattr_inode_iget(parent, ea_ino,
1150                                             le32_to_cpu(entry->e_hash),
1151                                             &ea_inode);
1152                 if (err)
1153                         continue;
1154
1155                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1156                 if (err) {
1157                         ext4_warning_inode(ea_inode,
1158                                            "Expand inode array err=%d", err);
1159                         iput(ea_inode);
1160                         continue;
1161                 }
1162
1163                 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1164                         ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1165                         ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1166                                               dirty));
1167                 if (err < 0) {
1168                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1169                                            err);
1170                         continue;
1171                 }
1172                 if (err > 0) {
1173                         err = ext4_journal_get_write_access(handle,
1174                                         parent->i_sb, bh, EXT4_JTR_NONE);
1175                         if (err) {
1176                                 ext4_warning_inode(ea_inode,
1177                                                 "Re-get write access err=%d",
1178                                                 err);
1179                                 continue;
1180                         }
1181                 }
1182
1183                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1184                 if (err) {
1185                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1186                                            err);
1187                         continue;
1188                 }
1189
1190                 if (!skip_quota)
1191                         ext4_xattr_inode_free_quota(parent, ea_inode,
1192                                               le32_to_cpu(entry->e_value_size));
1193
1194                 /*
1195                  * Forget about ea_inode within the same transaction that
1196                  * decrements the ref count. This avoids duplicate decrements in
1197                  * case the rest of the work spills over to subsequent
1198                  * transactions.
1199                  */
1200                 entry->e_value_inum = 0;
1201                 entry->e_value_size = 0;
1202
1203                 dirty = true;
1204         }
1205
1206         if (dirty) {
1207                 /*
1208                  * Note that we are deliberately skipping csum calculation for
1209                  * the final update because we do not expect any journal
1210                  * restarts until xattr block is freed.
1211                  */
1212
1213                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1214                 if (err)
1215                         ext4_warning_inode(parent,
1216                                            "handle dirty metadata err=%d", err);
1217         }
1218 }
1219
1220 /*
1221  * Release the xattr block BH: If the reference count is > 1, decrement it;
1222  * otherwise free the block.
1223  */
1224 static void
1225 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1226                          struct buffer_head *bh,
1227                          struct ext4_xattr_inode_array **ea_inode_array,
1228                          int extra_credits)
1229 {
1230         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1231         u32 hash, ref;
1232         int error = 0;
1233
1234         BUFFER_TRACE(bh, "get_write_access");
1235         error = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1236                                               EXT4_JTR_NONE);
1237         if (error)
1238                 goto out;
1239
1240         lock_buffer(bh);
1241         hash = le32_to_cpu(BHDR(bh)->h_hash);
1242         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1243         if (ref == 1) {
1244                 ea_bdebug(bh, "refcount now=0; freeing");
1245                 /*
1246                  * This must happen under buffer lock for
1247                  * ext4_xattr_block_set() to reliably detect freed block
1248                  */
1249                 if (ea_block_cache)
1250                         mb_cache_entry_delete(ea_block_cache, hash,
1251                                               bh->b_blocknr);
1252                 get_bh(bh);
1253                 unlock_buffer(bh);
1254
1255                 if (ext4_has_feature_ea_inode(inode->i_sb))
1256                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1257                                                      BFIRST(bh),
1258                                                      true /* block_csum */,
1259                                                      ea_inode_array,
1260                                                      extra_credits,
1261                                                      true /* skip_quota */);
1262                 ext4_free_blocks(handle, inode, bh, 0, 1,
1263                                  EXT4_FREE_BLOCKS_METADATA |
1264                                  EXT4_FREE_BLOCKS_FORGET);
1265         } else {
1266                 ref--;
1267                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1268                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1269                         struct mb_cache_entry *ce;
1270
1271                         if (ea_block_cache) {
1272                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1273                                                         bh->b_blocknr);
1274                                 if (ce) {
1275                                         ce->e_reusable = 1;
1276                                         mb_cache_entry_put(ea_block_cache, ce);
1277                                 }
1278                         }
1279                 }
1280
1281                 ext4_xattr_block_csum_set(inode, bh);
1282                 /*
1283                  * Beware of this ugliness: Releasing of xattr block references
1284                  * from different inodes can race and so we have to protect
1285                  * from a race where someone else frees the block (and releases
1286                  * its journal_head) before we are done dirtying the buffer. In
1287                  * nojournal mode this race is harmless and we actually cannot
1288                  * call ext4_handle_dirty_metadata() with locked buffer as
1289                  * that function can call sync_dirty_buffer() so for that case
1290                  * we handle the dirtying after unlocking the buffer.
1291                  */
1292                 if (ext4_handle_valid(handle))
1293                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1294                 unlock_buffer(bh);
1295                 if (!ext4_handle_valid(handle))
1296                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1297                 if (IS_SYNC(inode))
1298                         ext4_handle_sync(handle);
1299                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1300                 ea_bdebug(bh, "refcount now=%d; releasing",
1301                           le32_to_cpu(BHDR(bh)->h_refcount));
1302         }
1303 out:
1304         ext4_std_error(inode->i_sb, error);
1305         return;
1306 }
1307
1308 /*
1309  * Find the available free space for EAs. This also returns the total number of
1310  * bytes used by EA entries.
1311  */
1312 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1313                                     size_t *min_offs, void *base, int *total)
1314 {
1315         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1316                 if (!last->e_value_inum && last->e_value_size) {
1317                         size_t offs = le16_to_cpu(last->e_value_offs);
1318                         if (offs < *min_offs)
1319                                 *min_offs = offs;
1320                 }
1321                 if (total)
1322                         *total += EXT4_XATTR_LEN(last->e_name_len);
1323         }
1324         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1325 }
1326
1327 /*
1328  * Write the value of the EA in an inode.
1329  */
1330 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1331                                   const void *buf, int bufsize)
1332 {
1333         struct buffer_head *bh = NULL;
1334         unsigned long block = 0;
1335         int blocksize = ea_inode->i_sb->s_blocksize;
1336         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1337         int csize, wsize = 0;
1338         int ret = 0, ret2 = 0;
1339         int retries = 0;
1340
1341 retry:
1342         while (ret >= 0 && ret < max_blocks) {
1343                 struct ext4_map_blocks map;
1344                 map.m_lblk = block += ret;
1345                 map.m_len = max_blocks -= ret;
1346
1347                 ret = ext4_map_blocks(handle, ea_inode, &map,
1348                                       EXT4_GET_BLOCKS_CREATE);
1349                 if (ret <= 0) {
1350                         ext4_mark_inode_dirty(handle, ea_inode);
1351                         if (ret == -ENOSPC &&
1352                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1353                                 ret = 0;
1354                                 goto retry;
1355                         }
1356                         break;
1357                 }
1358         }
1359
1360         if (ret < 0)
1361                 return ret;
1362
1363         block = 0;
1364         while (wsize < bufsize) {
1365                 brelse(bh);
1366                 csize = (bufsize - wsize) > blocksize ? blocksize :
1367                                                                 bufsize - wsize;
1368                 bh = ext4_getblk(handle, ea_inode, block, 0);
1369                 if (IS_ERR(bh))
1370                         return PTR_ERR(bh);
1371                 if (!bh) {
1372                         WARN_ON_ONCE(1);
1373                         EXT4_ERROR_INODE(ea_inode,
1374                                          "ext4_getblk() return bh = NULL");
1375                         return -EFSCORRUPTED;
1376                 }
1377                 ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh,
1378                                                    EXT4_JTR_NONE);
1379                 if (ret)
1380                         goto out;
1381
1382                 memcpy(bh->b_data, buf, csize);
1383                 set_buffer_uptodate(bh);
1384                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1385
1386                 buf += csize;
1387                 wsize += csize;
1388                 block += 1;
1389         }
1390
1391         inode_lock(ea_inode);
1392         i_size_write(ea_inode, wsize);
1393         ext4_update_i_disksize(ea_inode, wsize);
1394         inode_unlock(ea_inode);
1395
1396         ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1397         if (unlikely(ret2 && !ret))
1398                 ret = ret2;
1399
1400 out:
1401         brelse(bh);
1402
1403         return ret;
1404 }
1405
1406 /*
1407  * Create an inode to store the value of a large EA.
1408  */
1409 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1410                                              struct inode *inode, u32 hash)
1411 {
1412         struct inode *ea_inode = NULL;
1413         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1414         int err;
1415
1416         /*
1417          * Let the next inode be the goal, so we try and allocate the EA inode
1418          * in the same group, or nearby one.
1419          */
1420         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1421                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1422                                   EXT4_EA_INODE_FL);
1423         if (!IS_ERR(ea_inode)) {
1424                 ea_inode->i_op = &ext4_file_inode_operations;
1425                 ea_inode->i_fop = &ext4_file_operations;
1426                 ext4_set_aops(ea_inode);
1427                 ext4_xattr_inode_set_class(ea_inode);
1428                 unlock_new_inode(ea_inode);
1429                 ext4_xattr_inode_set_ref(ea_inode, 1);
1430                 ext4_xattr_inode_set_hash(ea_inode, hash);
1431                 err = ext4_mark_inode_dirty(handle, ea_inode);
1432                 if (!err)
1433                         err = ext4_inode_attach_jinode(ea_inode);
1434                 if (err) {
1435                         iput(ea_inode);
1436                         return ERR_PTR(err);
1437                 }
1438
1439                 /*
1440                  * Xattr inodes are shared therefore quota charging is performed
1441                  * at a higher level.
1442                  */
1443                 dquot_free_inode(ea_inode);
1444                 dquot_drop(ea_inode);
1445                 inode_lock(ea_inode);
1446                 ea_inode->i_flags |= S_NOQUOTA;
1447                 inode_unlock(ea_inode);
1448         }
1449
1450         return ea_inode;
1451 }
1452
1453 static struct inode *
1454 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1455                             size_t value_len, u32 hash)
1456 {
1457         struct inode *ea_inode;
1458         struct mb_cache_entry *ce;
1459         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1460         void *ea_data;
1461
1462         if (!ea_inode_cache)
1463                 return NULL;
1464
1465         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1466         if (!ce)
1467                 return NULL;
1468
1469         WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1470                      !(current->flags & PF_MEMALLOC_NOFS));
1471
1472         ea_data = kvmalloc(value_len, GFP_KERNEL);
1473         if (!ea_data) {
1474                 mb_cache_entry_put(ea_inode_cache, ce);
1475                 return NULL;
1476         }
1477
1478         while (ce) {
1479                 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1480                                      EXT4_IGET_NORMAL);
1481                 if (!IS_ERR(ea_inode) &&
1482                     !is_bad_inode(ea_inode) &&
1483                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1484                     i_size_read(ea_inode) == value_len &&
1485                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1486                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1487                                                     value_len) &&
1488                     !memcmp(value, ea_data, value_len)) {
1489                         mb_cache_entry_touch(ea_inode_cache, ce);
1490                         mb_cache_entry_put(ea_inode_cache, ce);
1491                         kvfree(ea_data);
1492                         return ea_inode;
1493                 }
1494
1495                 if (!IS_ERR(ea_inode))
1496                         iput(ea_inode);
1497                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1498         }
1499         kvfree(ea_data);
1500         return NULL;
1501 }
1502
1503 /*
1504  * Add value of the EA in an inode.
1505  */
1506 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1507                                           const void *value, size_t value_len,
1508                                           struct inode **ret_inode)
1509 {
1510         struct inode *ea_inode;
1511         u32 hash;
1512         int err;
1513
1514         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1515         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1516         if (ea_inode) {
1517                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1518                 if (err) {
1519                         iput(ea_inode);
1520                         return err;
1521                 }
1522
1523                 *ret_inode = ea_inode;
1524                 return 0;
1525         }
1526
1527         /* Create an inode for the EA value */
1528         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1529         if (IS_ERR(ea_inode))
1530                 return PTR_ERR(ea_inode);
1531
1532         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1533         if (err) {
1534                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1535                 iput(ea_inode);
1536                 return err;
1537         }
1538
1539         if (EA_INODE_CACHE(inode))
1540                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1541                                       ea_inode->i_ino, true /* reusable */);
1542
1543         *ret_inode = ea_inode;
1544         return 0;
1545 }
1546
1547 /*
1548  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1549  * feature is enabled.
1550  */
1551 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1552
1553 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1554                                 struct ext4_xattr_search *s,
1555                                 handle_t *handle, struct inode *inode,
1556                                 bool is_block)
1557 {
1558         struct ext4_xattr_entry *last, *next;
1559         struct ext4_xattr_entry *here = s->here;
1560         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1561         int in_inode = i->in_inode;
1562         struct inode *old_ea_inode = NULL;
1563         struct inode *new_ea_inode = NULL;
1564         size_t old_size, new_size;
1565         int ret;
1566
1567         /* Space used by old and new values. */
1568         old_size = (!s->not_found && !here->e_value_inum) ?
1569                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1570         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1571
1572         /*
1573          * Optimization for the simple case when old and new values have the
1574          * same padded sizes. Not applicable if external inodes are involved.
1575          */
1576         if (new_size && new_size == old_size) {
1577                 size_t offs = le16_to_cpu(here->e_value_offs);
1578                 void *val = s->base + offs;
1579
1580                 here->e_value_size = cpu_to_le32(i->value_len);
1581                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1582                         memset(val, 0, new_size);
1583                 } else {
1584                         memcpy(val, i->value, i->value_len);
1585                         /* Clear padding bytes. */
1586                         memset(val + i->value_len, 0, new_size - i->value_len);
1587                 }
1588                 goto update_hash;
1589         }
1590
1591         /* Compute min_offs and last. */
1592         last = s->first;
1593         for (; !IS_LAST_ENTRY(last); last = next) {
1594                 next = EXT4_XATTR_NEXT(last);
1595                 if ((void *)next >= s->end) {
1596                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1597                         ret = -EFSCORRUPTED;
1598                         goto out;
1599                 }
1600                 if (!last->e_value_inum && last->e_value_size) {
1601                         size_t offs = le16_to_cpu(last->e_value_offs);
1602                         if (offs < min_offs)
1603                                 min_offs = offs;
1604                 }
1605         }
1606
1607         /* Check whether we have enough space. */
1608         if (i->value) {
1609                 size_t free;
1610
1611                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1612                 if (!s->not_found)
1613                         free += EXT4_XATTR_LEN(name_len) + old_size;
1614
1615                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1616                         ret = -ENOSPC;
1617                         goto out;
1618                 }
1619
1620                 /*
1621                  * If storing the value in an external inode is an option,
1622                  * reserve space for xattr entries/names in the external
1623                  * attribute block so that a long value does not occupy the
1624                  * whole space and prevent further entries being added.
1625                  */
1626                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1627                     new_size && is_block &&
1628                     (min_offs + old_size - new_size) <
1629                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1630                         ret = -ENOSPC;
1631                         goto out;
1632                 }
1633         }
1634
1635         /*
1636          * Getting access to old and new ea inodes is subject to failures.
1637          * Finish that work before doing any modifications to the xattr data.
1638          */
1639         if (!s->not_found && here->e_value_inum) {
1640                 ret = ext4_xattr_inode_iget(inode,
1641                                             le32_to_cpu(here->e_value_inum),
1642                                             le32_to_cpu(here->e_hash),
1643                                             &old_ea_inode);
1644                 if (ret) {
1645                         old_ea_inode = NULL;
1646                         goto out;
1647                 }
1648         }
1649         if (i->value && in_inode) {
1650                 WARN_ON_ONCE(!i->value_len);
1651
1652                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1653                 if (ret)
1654                         goto out;
1655
1656                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1657                                                      i->value_len,
1658                                                      &new_ea_inode);
1659                 if (ret) {
1660                         new_ea_inode = NULL;
1661                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1662                         goto out;
1663                 }
1664         }
1665
1666         if (old_ea_inode) {
1667                 /* We are ready to release ref count on the old_ea_inode. */
1668                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1669                 if (ret) {
1670                         /* Release newly required ref count on new_ea_inode. */
1671                         if (new_ea_inode) {
1672                                 int err;
1673
1674                                 err = ext4_xattr_inode_dec_ref(handle,
1675                                                                new_ea_inode);
1676                                 if (err)
1677                                         ext4_warning_inode(new_ea_inode,
1678                                                   "dec ref new_ea_inode err=%d",
1679                                                   err);
1680                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1681                                                             i->value_len);
1682                         }
1683                         goto out;
1684                 }
1685
1686                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1687                                             le32_to_cpu(here->e_value_size));
1688         }
1689
1690         /* No failures allowed past this point. */
1691
1692         if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1693                 /* Remove the old value. */
1694                 void *first_val = s->base + min_offs;
1695                 size_t offs = le16_to_cpu(here->e_value_offs);
1696                 void *val = s->base + offs;
1697
1698                 memmove(first_val + old_size, first_val, val - first_val);
1699                 memset(first_val, 0, old_size);
1700                 min_offs += old_size;
1701
1702                 /* Adjust all value offsets. */
1703                 last = s->first;
1704                 while (!IS_LAST_ENTRY(last)) {
1705                         size_t o = le16_to_cpu(last->e_value_offs);
1706
1707                         if (!last->e_value_inum &&
1708                             last->e_value_size && o < offs)
1709                                 last->e_value_offs = cpu_to_le16(o + old_size);
1710                         last = EXT4_XATTR_NEXT(last);
1711                 }
1712         }
1713
1714         if (!i->value) {
1715                 /* Remove old name. */
1716                 size_t size = EXT4_XATTR_LEN(name_len);
1717
1718                 last = ENTRY((void *)last - size);
1719                 memmove(here, (void *)here + size,
1720                         (void *)last - (void *)here + sizeof(__u32));
1721                 memset(last, 0, size);
1722         } else if (s->not_found) {
1723                 /* Insert new name. */
1724                 size_t size = EXT4_XATTR_LEN(name_len);
1725                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1726
1727                 memmove((void *)here + size, here, rest);
1728                 memset(here, 0, size);
1729                 here->e_name_index = i->name_index;
1730                 here->e_name_len = name_len;
1731                 memcpy(here->e_name, i->name, name_len);
1732         } else {
1733                 /* This is an update, reset value info. */
1734                 here->e_value_inum = 0;
1735                 here->e_value_offs = 0;
1736                 here->e_value_size = 0;
1737         }
1738
1739         if (i->value) {
1740                 /* Insert new value. */
1741                 if (in_inode) {
1742                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1743                 } else if (i->value_len) {
1744                         void *val = s->base + min_offs - new_size;
1745
1746                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1747                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1748                                 memset(val, 0, new_size);
1749                         } else {
1750                                 memcpy(val, i->value, i->value_len);
1751                                 /* Clear padding bytes. */
1752                                 memset(val + i->value_len, 0,
1753                                        new_size - i->value_len);
1754                         }
1755                 }
1756                 here->e_value_size = cpu_to_le32(i->value_len);
1757         }
1758
1759 update_hash:
1760         if (i->value) {
1761                 __le32 hash = 0;
1762
1763                 /* Entry hash calculation. */
1764                 if (in_inode) {
1765                         __le32 crc32c_hash;
1766
1767                         /*
1768                          * Feed crc32c hash instead of the raw value for entry
1769                          * hash calculation. This is to avoid walking
1770                          * potentially long value buffer again.
1771                          */
1772                         crc32c_hash = cpu_to_le32(
1773                                        ext4_xattr_inode_get_hash(new_ea_inode));
1774                         hash = ext4_xattr_hash_entry(here->e_name,
1775                                                      here->e_name_len,
1776                                                      &crc32c_hash, 1);
1777                 } else if (is_block) {
1778                         __le32 *value = s->base + le16_to_cpu(
1779                                                         here->e_value_offs);
1780
1781                         hash = ext4_xattr_hash_entry(here->e_name,
1782                                                      here->e_name_len, value,
1783                                                      new_size >> 2);
1784                 }
1785                 here->e_hash = hash;
1786         }
1787
1788         if (is_block)
1789                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1790
1791         ret = 0;
1792 out:
1793         iput(old_ea_inode);
1794         iput(new_ea_inode);
1795         return ret;
1796 }
1797
1798 struct ext4_xattr_block_find {
1799         struct ext4_xattr_search s;
1800         struct buffer_head *bh;
1801 };
1802
1803 static int
1804 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1805                       struct ext4_xattr_block_find *bs)
1806 {
1807         struct super_block *sb = inode->i_sb;
1808         int error;
1809
1810         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1811                   i->name_index, i->name, i->value, (long)i->value_len);
1812
1813         if (EXT4_I(inode)->i_file_acl) {
1814                 /* The inode already has an extended attribute block. */
1815                 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1816                 if (IS_ERR(bs->bh)) {
1817                         error = PTR_ERR(bs->bh);
1818                         bs->bh = NULL;
1819                         return error;
1820                 }
1821                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1822                         atomic_read(&(bs->bh->b_count)),
1823                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1824                 error = ext4_xattr_check_block(inode, bs->bh);
1825                 if (error)
1826                         return error;
1827                 /* Find the named attribute. */
1828                 bs->s.base = BHDR(bs->bh);
1829                 bs->s.first = BFIRST(bs->bh);
1830                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1831                 bs->s.here = bs->s.first;
1832                 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1833                                          i->name_index, i->name, 1);
1834                 if (error && error != -ENODATA)
1835                         return error;
1836                 bs->s.not_found = error;
1837         }
1838         return 0;
1839 }
1840
1841 static int
1842 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1843                      struct ext4_xattr_info *i,
1844                      struct ext4_xattr_block_find *bs)
1845 {
1846         struct super_block *sb = inode->i_sb;
1847         struct buffer_head *new_bh = NULL;
1848         struct ext4_xattr_search s_copy = bs->s;
1849         struct ext4_xattr_search *s = &s_copy;
1850         struct mb_cache_entry *ce = NULL;
1851         int error = 0;
1852         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1853         struct inode *ea_inode = NULL, *tmp_inode;
1854         size_t old_ea_inode_quota = 0;
1855         unsigned int ea_ino;
1856
1857
1858 #define header(x) ((struct ext4_xattr_header *)(x))
1859
1860         if (s->base) {
1861                 BUFFER_TRACE(bs->bh, "get_write_access");
1862                 error = ext4_journal_get_write_access(handle, sb, bs->bh,
1863                                                       EXT4_JTR_NONE);
1864                 if (error)
1865                         goto cleanup;
1866                 lock_buffer(bs->bh);
1867
1868                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1869                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1870
1871                         /*
1872                          * This must happen under buffer lock for
1873                          * ext4_xattr_block_set() to reliably detect modified
1874                          * block
1875                          */
1876                         if (ea_block_cache)
1877                                 mb_cache_entry_delete(ea_block_cache, hash,
1878                                                       bs->bh->b_blocknr);
1879                         ea_bdebug(bs->bh, "modifying in-place");
1880                         error = ext4_xattr_set_entry(i, s, handle, inode,
1881                                                      true /* is_block */);
1882                         ext4_xattr_block_csum_set(inode, bs->bh);
1883                         unlock_buffer(bs->bh);
1884                         if (error == -EFSCORRUPTED)
1885                                 goto bad_block;
1886                         if (!error)
1887                                 error = ext4_handle_dirty_metadata(handle,
1888                                                                    inode,
1889                                                                    bs->bh);
1890                         if (error)
1891                                 goto cleanup;
1892                         goto inserted;
1893                 } else {
1894                         int offset = (char *)s->here - bs->bh->b_data;
1895
1896                         unlock_buffer(bs->bh);
1897                         ea_bdebug(bs->bh, "cloning");
1898                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1899                         error = -ENOMEM;
1900                         if (s->base == NULL)
1901                                 goto cleanup;
1902                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1903                         s->first = ENTRY(header(s->base)+1);
1904                         header(s->base)->h_refcount = cpu_to_le32(1);
1905                         s->here = ENTRY(s->base + offset);
1906                         s->end = s->base + bs->bh->b_size;
1907
1908                         /*
1909                          * If existing entry points to an xattr inode, we need
1910                          * to prevent ext4_xattr_set_entry() from decrementing
1911                          * ref count on it because the reference belongs to the
1912                          * original block. In this case, make the entry look
1913                          * like it has an empty value.
1914                          */
1915                         if (!s->not_found && s->here->e_value_inum) {
1916                                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1917                                 error = ext4_xattr_inode_iget(inode, ea_ino,
1918                                               le32_to_cpu(s->here->e_hash),
1919                                               &tmp_inode);
1920                                 if (error)
1921                                         goto cleanup;
1922
1923                                 if (!ext4_test_inode_state(tmp_inode,
1924                                                 EXT4_STATE_LUSTRE_EA_INODE)) {
1925                                         /*
1926                                          * Defer quota free call for previous
1927                                          * inode until success is guaranteed.
1928                                          */
1929                                         old_ea_inode_quota = le32_to_cpu(
1930                                                         s->here->e_value_size);
1931                                 }
1932                                 iput(tmp_inode);
1933
1934                                 s->here->e_value_inum = 0;
1935                                 s->here->e_value_size = 0;
1936                         }
1937                 }
1938         } else {
1939                 /* Allocate a buffer where we construct the new block. */
1940                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1941                 error = -ENOMEM;
1942                 if (s->base == NULL)
1943                         goto cleanup;
1944                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1945                 header(s->base)->h_blocks = cpu_to_le32(1);
1946                 header(s->base)->h_refcount = cpu_to_le32(1);
1947                 s->first = ENTRY(header(s->base)+1);
1948                 s->here = ENTRY(header(s->base)+1);
1949                 s->end = s->base + sb->s_blocksize;
1950         }
1951
1952         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1953         if (error == -EFSCORRUPTED)
1954                 goto bad_block;
1955         if (error)
1956                 goto cleanup;
1957
1958         if (i->value && s->here->e_value_inum) {
1959                 /*
1960                  * A ref count on ea_inode has been taken as part of the call to
1961                  * ext4_xattr_set_entry() above. We would like to drop this
1962                  * extra ref but we have to wait until the xattr block is
1963                  * initialized and has its own ref count on the ea_inode.
1964                  */
1965                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1966                 error = ext4_xattr_inode_iget(inode, ea_ino,
1967                                               le32_to_cpu(s->here->e_hash),
1968                                               &ea_inode);
1969                 if (error) {
1970                         ea_inode = NULL;
1971                         goto cleanup;
1972                 }
1973         }
1974
1975 inserted:
1976         if (!IS_LAST_ENTRY(s->first)) {
1977                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1978                                                      &ce);
1979                 if (new_bh) {
1980                         /* We found an identical block in the cache. */
1981                         if (new_bh == bs->bh)
1982                                 ea_bdebug(new_bh, "keeping");
1983                         else {
1984                                 u32 ref;
1985
1986                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
1987
1988                                 /* The old block is released after updating
1989                                    the inode. */
1990                                 error = dquot_alloc_block(inode,
1991                                                 EXT4_C2B(EXT4_SB(sb), 1));
1992                                 if (error)
1993                                         goto cleanup;
1994                                 BUFFER_TRACE(new_bh, "get_write_access");
1995                                 error = ext4_journal_get_write_access(
1996                                                 handle, sb, new_bh,
1997                                                 EXT4_JTR_NONE);
1998                                 if (error)
1999                                         goto cleanup_dquot;
2000                                 lock_buffer(new_bh);
2001                                 /*
2002                                  * We have to be careful about races with
2003                                  * freeing, rehashing or adding references to
2004                                  * xattr block. Once we hold buffer lock xattr
2005                                  * block's state is stable so we can check
2006                                  * whether the block got freed / rehashed or
2007                                  * not.  Since we unhash mbcache entry under
2008                                  * buffer lock when freeing / rehashing xattr
2009                                  * block, checking whether entry is still
2010                                  * hashed is reliable. Same rules hold for
2011                                  * e_reusable handling.
2012                                  */
2013                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2014                                     !ce->e_reusable) {
2015                                         /*
2016                                          * Undo everything and check mbcache
2017                                          * again.
2018                                          */
2019                                         unlock_buffer(new_bh);
2020                                         dquot_free_block(inode,
2021                                                          EXT4_C2B(EXT4_SB(sb),
2022                                                                   1));
2023                                         brelse(new_bh);
2024                                         mb_cache_entry_put(ea_block_cache, ce);
2025                                         ce = NULL;
2026                                         new_bh = NULL;
2027                                         goto inserted;
2028                                 }
2029                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2030                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2031                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2032                                         ce->e_reusable = 0;
2033                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2034                                           ref);
2035                                 ext4_xattr_block_csum_set(inode, new_bh);
2036                                 unlock_buffer(new_bh);
2037                                 error = ext4_handle_dirty_metadata(handle,
2038                                                                    inode,
2039                                                                    new_bh);
2040                                 if (error)
2041                                         goto cleanup_dquot;
2042                         }
2043                         mb_cache_entry_touch(ea_block_cache, ce);
2044                         mb_cache_entry_put(ea_block_cache, ce);
2045                         ce = NULL;
2046                 } else if (bs->bh && s->base == bs->bh->b_data) {
2047                         /* We were modifying this block in-place. */
2048                         ea_bdebug(bs->bh, "keeping this block");
2049                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2050                         new_bh = bs->bh;
2051                         get_bh(new_bh);
2052                 } else {
2053                         /* We need to allocate a new block */
2054                         ext4_fsblk_t goal, block;
2055
2056                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2057
2058                         goal = ext4_group_first_block_no(sb,
2059                                                 EXT4_I(inode)->i_block_group);
2060
2061                         /* non-extent files can't have physical blocks past 2^32 */
2062                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2063                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2064
2065                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2066                                                      NULL, &error);
2067                         if (error)
2068                                 goto cleanup;
2069
2070                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2071                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2072
2073                         ea_idebug(inode, "creating block %llu",
2074                                   (unsigned long long)block);
2075
2076                         new_bh = sb_getblk(sb, block);
2077                         if (unlikely(!new_bh)) {
2078                                 error = -ENOMEM;
2079 getblk_failed:
2080                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2081                                                  EXT4_FREE_BLOCKS_METADATA);
2082                                 goto cleanup;
2083                         }
2084                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2085                                                       ENTRY(header(s->base)+1));
2086                         if (error)
2087                                 goto getblk_failed;
2088                         if (ea_inode) {
2089                                 /* Drop the extra ref on ea_inode. */
2090                                 error = ext4_xattr_inode_dec_ref(handle,
2091                                                                  ea_inode);
2092                                 if (error)
2093                                         ext4_warning_inode(ea_inode,
2094                                                            "dec ref error=%d",
2095                                                            error);
2096                                 iput(ea_inode);
2097                                 ea_inode = NULL;
2098                         }
2099
2100                         lock_buffer(new_bh);
2101                         error = ext4_journal_get_create_access(handle, sb,
2102                                                         new_bh, EXT4_JTR_NONE);
2103                         if (error) {
2104                                 unlock_buffer(new_bh);
2105                                 error = -EIO;
2106                                 goto getblk_failed;
2107                         }
2108                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2109                         ext4_xattr_block_csum_set(inode, new_bh);
2110                         set_buffer_uptodate(new_bh);
2111                         unlock_buffer(new_bh);
2112                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2113                         error = ext4_handle_dirty_metadata(handle, inode,
2114                                                            new_bh);
2115                         if (error)
2116                                 goto cleanup;
2117                 }
2118         }
2119
2120         if (old_ea_inode_quota)
2121                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2122
2123         /* Update the inode. */
2124         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2125
2126         /* Drop the previous xattr block. */
2127         if (bs->bh && bs->bh != new_bh) {
2128                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2129
2130                 ext4_xattr_release_block(handle, inode, bs->bh,
2131                                          &ea_inode_array,
2132                                          0 /* extra_credits */);
2133                 ext4_xattr_inode_array_free(ea_inode_array);
2134         }
2135         error = 0;
2136
2137 cleanup:
2138         if (ea_inode) {
2139                 int error2;
2140
2141                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2142                 if (error2)
2143                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2144                                            error2);
2145
2146                 /* If there was an error, revert the quota charge. */
2147                 if (error)
2148                         ext4_xattr_inode_free_quota(inode, ea_inode,
2149                                                     i_size_read(ea_inode));
2150                 iput(ea_inode);
2151         }
2152         if (ce)
2153                 mb_cache_entry_put(ea_block_cache, ce);
2154         brelse(new_bh);
2155         if (!(bs->bh && s->base == bs->bh->b_data))
2156                 kfree(s->base);
2157
2158         return error;
2159
2160 cleanup_dquot:
2161         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2162         goto cleanup;
2163
2164 bad_block:
2165         EXT4_ERROR_INODE(inode, "bad block %llu",
2166                          EXT4_I(inode)->i_file_acl);
2167         goto cleanup;
2168
2169 #undef header
2170 }
2171
2172 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2173                           struct ext4_xattr_ibody_find *is)
2174 {
2175         struct ext4_xattr_ibody_header *header;
2176         struct ext4_inode *raw_inode;
2177         int error;
2178
2179         if (EXT4_I(inode)->i_extra_isize == 0)
2180                 return 0;
2181         raw_inode = ext4_raw_inode(&is->iloc);
2182         header = IHDR(inode, raw_inode);
2183         is->s.base = is->s.first = IFIRST(header);
2184         is->s.here = is->s.first;
2185         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2186         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2187                 error = xattr_check_inode(inode, header, is->s.end);
2188                 if (error)
2189                         return error;
2190                 /* Find the named attribute. */
2191                 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2192                                          i->name_index, i->name, 0);
2193                 if (error && error != -ENODATA)
2194                         return error;
2195                 is->s.not_found = error;
2196         }
2197         return 0;
2198 }
2199
2200 int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2201                                 struct ext4_xattr_info *i,
2202                                 struct ext4_xattr_ibody_find *is)
2203 {
2204         struct ext4_xattr_ibody_header *header;
2205         struct ext4_xattr_search *s = &is->s;
2206         int error;
2207
2208         if (EXT4_I(inode)->i_extra_isize == 0)
2209                 return -ENOSPC;
2210         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2211         if (error)
2212                 return error;
2213         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2214         if (!IS_LAST_ENTRY(s->first)) {
2215                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2216                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2217         } else {
2218                 header->h_magic = cpu_to_le32(0);
2219                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2220         }
2221         return 0;
2222 }
2223
2224 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2225                                  struct ext4_xattr_info *i)
2226 {
2227         void *value;
2228
2229         /* When e_value_inum is set the value is stored externally. */
2230         if (s->here->e_value_inum)
2231                 return 0;
2232         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2233                 return 0;
2234         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2235         return !memcmp(value, i->value, i->value_len);
2236 }
2237
2238 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2239 {
2240         struct buffer_head *bh;
2241         int error;
2242
2243         if (!EXT4_I(inode)->i_file_acl)
2244                 return NULL;
2245         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2246         if (IS_ERR(bh))
2247                 return bh;
2248         error = ext4_xattr_check_block(inode, bh);
2249         if (error) {
2250                 brelse(bh);
2251                 return ERR_PTR(error);
2252         }
2253         return bh;
2254 }
2255
2256 /*
2257  * ext4_xattr_set_handle()
2258  *
2259  * Create, replace or remove an extended attribute for this inode.  Value
2260  * is NULL to remove an existing extended attribute, and non-NULL to
2261  * either replace an existing extended attribute, or create a new extended
2262  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2263  * specify that an extended attribute must exist and must not exist
2264  * previous to the call, respectively.
2265  *
2266  * Returns 0, or a negative error number on failure.
2267  */
2268 int
2269 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2270                       const char *name, const void *value, size_t value_len,
2271                       int flags)
2272 {
2273         struct ext4_xattr_info i = {
2274                 .name_index = name_index,
2275                 .name = name,
2276                 .value = value,
2277                 .value_len = value_len,
2278                 .in_inode = 0,
2279         };
2280         struct ext4_xattr_ibody_find is = {
2281                 .s = { .not_found = -ENODATA, },
2282         };
2283         struct ext4_xattr_block_find bs = {
2284                 .s = { .not_found = -ENODATA, },
2285         };
2286         int no_expand;
2287         int error;
2288
2289         if (!name)
2290                 return -EINVAL;
2291         if (strlen(name) > 255)
2292                 return -ERANGE;
2293
2294         ext4_write_lock_xattr(inode, &no_expand);
2295
2296         /* Check journal credits under write lock. */
2297         if (ext4_handle_valid(handle)) {
2298                 struct buffer_head *bh;
2299                 int credits;
2300
2301                 bh = ext4_xattr_get_block(inode);
2302                 if (IS_ERR(bh)) {
2303                         error = PTR_ERR(bh);
2304                         goto cleanup;
2305                 }
2306
2307                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2308                                                    value_len,
2309                                                    flags & XATTR_CREATE);
2310                 brelse(bh);
2311
2312                 if (jbd2_handle_buffer_credits(handle) < credits) {
2313                         error = -ENOSPC;
2314                         goto cleanup;
2315                 }
2316                 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2317         }
2318
2319         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2320         if (error)
2321                 goto cleanup;
2322
2323         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2324                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2325                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2326                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2327         }
2328
2329         error = ext4_xattr_ibody_find(inode, &i, &is);
2330         if (error)
2331                 goto cleanup;
2332         if (is.s.not_found)
2333                 error = ext4_xattr_block_find(inode, &i, &bs);
2334         if (error)
2335                 goto cleanup;
2336         if (is.s.not_found && bs.s.not_found) {
2337                 error = -ENODATA;
2338                 if (flags & XATTR_REPLACE)
2339                         goto cleanup;
2340                 error = 0;
2341                 if (!value)
2342                         goto cleanup;
2343         } else {
2344                 error = -EEXIST;
2345                 if (flags & XATTR_CREATE)
2346                         goto cleanup;
2347         }
2348
2349         if (!value) {
2350                 if (!is.s.not_found)
2351                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2352                 else if (!bs.s.not_found)
2353                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2354         } else {
2355                 error = 0;
2356                 /* Xattr value did not change? Save us some work and bail out */
2357                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2358                         goto cleanup;
2359                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2360                         goto cleanup;
2361
2362                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2363                     (EXT4_XATTR_SIZE(i.value_len) >
2364                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2365                         i.in_inode = 1;
2366 retry_inode:
2367                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2368                 if (!error && !bs.s.not_found) {
2369                         i.value = NULL;
2370                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2371                 } else if (error == -ENOSPC) {
2372                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2373                                 brelse(bs.bh);
2374                                 bs.bh = NULL;
2375                                 error = ext4_xattr_block_find(inode, &i, &bs);
2376                                 if (error)
2377                                         goto cleanup;
2378                         }
2379                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2380                         if (!error && !is.s.not_found) {
2381                                 i.value = NULL;
2382                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2383                                                              &is);
2384                         } else if (error == -ENOSPC) {
2385                                 /*
2386                                  * Xattr does not fit in the block, store at
2387                                  * external inode if possible.
2388                                  */
2389                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2390                                     i.value_len && !i.in_inode) {
2391                                         i.in_inode = 1;
2392                                         goto retry_inode;
2393                                 }
2394                         }
2395                 }
2396         }
2397         if (!error) {
2398                 ext4_xattr_update_super_block(handle, inode->i_sb);
2399                 inode->i_ctime = current_time(inode);
2400                 if (!value)
2401                         no_expand = 0;
2402                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2403                 /*
2404                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2405                  * error != 0.
2406                  */
2407                 is.iloc.bh = NULL;
2408                 if (IS_SYNC(inode))
2409                         ext4_handle_sync(handle);
2410         }
2411         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2412
2413 cleanup:
2414         brelse(is.iloc.bh);
2415         brelse(bs.bh);
2416         ext4_write_unlock_xattr(inode, &no_expand);
2417         return error;
2418 }
2419
2420 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2421                            bool is_create, int *credits)
2422 {
2423         struct buffer_head *bh;
2424         int err;
2425
2426         *credits = 0;
2427
2428         if (!EXT4_SB(inode->i_sb)->s_journal)
2429                 return 0;
2430
2431         down_read(&EXT4_I(inode)->xattr_sem);
2432
2433         bh = ext4_xattr_get_block(inode);
2434         if (IS_ERR(bh)) {
2435                 err = PTR_ERR(bh);
2436         } else {
2437                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2438                                                     value_len, is_create);
2439                 brelse(bh);
2440                 err = 0;
2441         }
2442
2443         up_read(&EXT4_I(inode)->xattr_sem);
2444         return err;
2445 }
2446
2447 /*
2448  * ext4_xattr_set()
2449  *
2450  * Like ext4_xattr_set_handle, but start from an inode. This extended
2451  * attribute modification is a filesystem transaction by itself.
2452  *
2453  * Returns 0, or a negative error number on failure.
2454  */
2455 int
2456 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2457                const void *value, size_t value_len, int flags)
2458 {
2459         handle_t *handle;
2460         struct super_block *sb = inode->i_sb;
2461         int error, retries = 0;
2462         int credits;
2463
2464         error = dquot_initialize(inode);
2465         if (error)
2466                 return error;
2467
2468 retry:
2469         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2470                                        &credits);
2471         if (error)
2472                 return error;
2473
2474         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2475         if (IS_ERR(handle)) {
2476                 error = PTR_ERR(handle);
2477         } else {
2478                 int error2;
2479
2480                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2481                                               value, value_len, flags);
2482                 error2 = ext4_journal_stop(handle);
2483                 if (error == -ENOSPC &&
2484                     ext4_should_retry_alloc(sb, &retries))
2485                         goto retry;
2486                 if (error == 0)
2487                         error = error2;
2488         }
2489         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
2490
2491         return error;
2492 }
2493
2494 /*
2495  * Shift the EA entries in the inode to create space for the increased
2496  * i_extra_isize.
2497  */
2498 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2499                                      int value_offs_shift, void *to,
2500                                      void *from, size_t n)
2501 {
2502         struct ext4_xattr_entry *last = entry;
2503         int new_offs;
2504
2505         /* We always shift xattr headers further thus offsets get lower */
2506         BUG_ON(value_offs_shift > 0);
2507
2508         /* Adjust the value offsets of the entries */
2509         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2510                 if (!last->e_value_inum && last->e_value_size) {
2511                         new_offs = le16_to_cpu(last->e_value_offs) +
2512                                                         value_offs_shift;
2513                         last->e_value_offs = cpu_to_le16(new_offs);
2514                 }
2515         }
2516         /* Shift the entries by n bytes */
2517         memmove(to, from, n);
2518 }
2519
2520 /*
2521  * Move xattr pointed to by 'entry' from inode into external xattr block
2522  */
2523 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2524                                     struct ext4_inode *raw_inode,
2525                                     struct ext4_xattr_entry *entry)
2526 {
2527         struct ext4_xattr_ibody_find *is = NULL;
2528         struct ext4_xattr_block_find *bs = NULL;
2529         char *buffer = NULL, *b_entry_name = NULL;
2530         size_t value_size = le32_to_cpu(entry->e_value_size);
2531         struct ext4_xattr_info i = {
2532                 .value = NULL,
2533                 .value_len = 0,
2534                 .name_index = entry->e_name_index,
2535                 .in_inode = !!entry->e_value_inum,
2536         };
2537         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2538         int error;
2539
2540         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2541         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2542         buffer = kmalloc(value_size, GFP_NOFS);
2543         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2544         if (!is || !bs || !buffer || !b_entry_name) {
2545                 error = -ENOMEM;
2546                 goto out;
2547         }
2548
2549         is->s.not_found = -ENODATA;
2550         bs->s.not_found = -ENODATA;
2551         is->iloc.bh = NULL;
2552         bs->bh = NULL;
2553
2554         /* Save the entry name and the entry value */
2555         if (entry->e_value_inum) {
2556                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2557                 if (error)
2558                         goto out;
2559         } else {
2560                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2561                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2562         }
2563
2564         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2565         b_entry_name[entry->e_name_len] = '\0';
2566         i.name = b_entry_name;
2567
2568         error = ext4_get_inode_loc(inode, &is->iloc);
2569         if (error)
2570                 goto out;
2571
2572         error = ext4_xattr_ibody_find(inode, &i, is);
2573         if (error)
2574                 goto out;
2575
2576         /* Remove the chosen entry from the inode */
2577         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2578         if (error)
2579                 goto out;
2580
2581         i.value = buffer;
2582         i.value_len = value_size;
2583         error = ext4_xattr_block_find(inode, &i, bs);
2584         if (error)
2585                 goto out;
2586
2587         /* Add entry which was removed from the inode into the block */
2588         error = ext4_xattr_block_set(handle, inode, &i, bs);
2589         if (error)
2590                 goto out;
2591         error = 0;
2592 out:
2593         kfree(b_entry_name);
2594         kfree(buffer);
2595         if (is)
2596                 brelse(is->iloc.bh);
2597         if (bs)
2598                 brelse(bs->bh);
2599         kfree(is);
2600         kfree(bs);
2601
2602         return error;
2603 }
2604
2605 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2606                                        struct ext4_inode *raw_inode,
2607                                        int isize_diff, size_t ifree,
2608                                        size_t bfree, int *total_ino)
2609 {
2610         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2611         struct ext4_xattr_entry *small_entry;
2612         struct ext4_xattr_entry *entry;
2613         struct ext4_xattr_entry *last;
2614         unsigned int entry_size;        /* EA entry size */
2615         unsigned int total_size;        /* EA entry size + value size */
2616         unsigned int min_total_size;
2617         int error;
2618
2619         while (isize_diff > ifree) {
2620                 entry = NULL;
2621                 small_entry = NULL;
2622                 min_total_size = ~0U;
2623                 last = IFIRST(header);
2624                 /* Find the entry best suited to be pushed into EA block */
2625                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2626                         /* never move system.data out of the inode */
2627                         if ((last->e_name_len == 4) &&
2628                             (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2629                             !memcmp(last->e_name, "data", 4))
2630                                 continue;
2631                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2632                         if (!last->e_value_inum)
2633                                 total_size += EXT4_XATTR_SIZE(
2634                                                le32_to_cpu(last->e_value_size));
2635                         if (total_size <= bfree &&
2636                             total_size < min_total_size) {
2637                                 if (total_size + ifree < isize_diff) {
2638                                         small_entry = last;
2639                                 } else {
2640                                         entry = last;
2641                                         min_total_size = total_size;
2642                                 }
2643                         }
2644                 }
2645
2646                 if (entry == NULL) {
2647                         if (small_entry == NULL)
2648                                 return -ENOSPC;
2649                         entry = small_entry;
2650                 }
2651
2652                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2653                 total_size = entry_size;
2654                 if (!entry->e_value_inum)
2655                         total_size += EXT4_XATTR_SIZE(
2656                                               le32_to_cpu(entry->e_value_size));
2657                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2658                                                  entry);
2659                 if (error)
2660                         return error;
2661
2662                 *total_ino -= entry_size;
2663                 ifree += total_size;
2664                 bfree -= total_size;
2665         }
2666
2667         return 0;
2668 }
2669
2670 /*
2671  * Expand an inode by new_extra_isize bytes when EAs are present.
2672  * Returns 0 on success or negative error number on failure.
2673  */
2674 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2675                                struct ext4_inode *raw_inode, handle_t *handle)
2676 {
2677         struct ext4_xattr_ibody_header *header;
2678         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2679         static unsigned int mnt_count;
2680         size_t min_offs;
2681         size_t ifree, bfree;
2682         int total_ino;
2683         void *base, *end;
2684         int error = 0, tried_min_extra_isize = 0;
2685         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2686         int isize_diff; /* How much do we need to grow i_extra_isize */
2687
2688 retry:
2689         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2690         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2691                 return 0;
2692
2693         header = IHDR(inode, raw_inode);
2694
2695         /*
2696          * Check if enough free space is available in the inode to shift the
2697          * entries ahead by new_extra_isize.
2698          */
2699
2700         base = IFIRST(header);
2701         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2702         min_offs = end - base;
2703         total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2704
2705         error = xattr_check_inode(inode, header, end);
2706         if (error)
2707                 goto cleanup;
2708
2709         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2710         if (ifree >= isize_diff)
2711                 goto shift;
2712
2713         /*
2714          * Enough free space isn't available in the inode, check if
2715          * EA block can hold new_extra_isize bytes.
2716          */
2717         if (EXT4_I(inode)->i_file_acl) {
2718                 struct buffer_head *bh;
2719
2720                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2721                 if (IS_ERR(bh)) {
2722                         error = PTR_ERR(bh);
2723                         goto cleanup;
2724                 }
2725                 error = ext4_xattr_check_block(inode, bh);
2726                 if (error) {
2727                         brelse(bh);
2728                         goto cleanup;
2729                 }
2730                 base = BHDR(bh);
2731                 end = bh->b_data + bh->b_size;
2732                 min_offs = end - base;
2733                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2734                                               NULL);
2735                 brelse(bh);
2736                 if (bfree + ifree < isize_diff) {
2737                         if (!tried_min_extra_isize && s_min_extra_isize) {
2738                                 tried_min_extra_isize++;
2739                                 new_extra_isize = s_min_extra_isize;
2740                                 goto retry;
2741                         }
2742                         error = -ENOSPC;
2743                         goto cleanup;
2744                 }
2745         } else {
2746                 bfree = inode->i_sb->s_blocksize;
2747         }
2748
2749         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2750                                             isize_diff, ifree, bfree,
2751                                             &total_ino);
2752         if (error) {
2753                 if (error == -ENOSPC && !tried_min_extra_isize &&
2754                     s_min_extra_isize) {
2755                         tried_min_extra_isize++;
2756                         new_extra_isize = s_min_extra_isize;
2757                         goto retry;
2758                 }
2759                 goto cleanup;
2760         }
2761 shift:
2762         /* Adjust the offsets and shift the remaining entries ahead */
2763         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2764                         - new_extra_isize, (void *)raw_inode +
2765                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2766                         (void *)header, total_ino);
2767         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2768
2769 cleanup:
2770         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2771                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2772                              inode->i_ino);
2773                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2774         }
2775         return error;
2776 }
2777
2778 #define EIA_INCR 16 /* must be 2^n */
2779 #define EIA_MASK (EIA_INCR - 1)
2780
2781 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2782  * If @ea_inode_array is new or full it will be grown and the old
2783  * contents copied over.
2784  */
2785 static int
2786 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2787                         struct inode *inode)
2788 {
2789         if (*ea_inode_array == NULL) {
2790                 /*
2791                  * Start with 15 inodes, so it fits into a power-of-two size.
2792                  * If *ea_inode_array is NULL, this is essentially offsetof()
2793                  */
2794                 (*ea_inode_array) =
2795                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2796                                          inodes[EIA_MASK]),
2797                                 GFP_NOFS);
2798                 if (*ea_inode_array == NULL)
2799                         return -ENOMEM;
2800                 (*ea_inode_array)->count = 0;
2801         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2802                 /* expand the array once all 15 + n * 16 slots are full */
2803                 struct ext4_xattr_inode_array *new_array = NULL;
2804                 int count = (*ea_inode_array)->count;
2805
2806                 /* if new_array is NULL, this is essentially offsetof() */
2807                 new_array = kmalloc(
2808                                 offsetof(struct ext4_xattr_inode_array,
2809                                          inodes[count + EIA_INCR]),
2810                                 GFP_NOFS);
2811                 if (new_array == NULL)
2812                         return -ENOMEM;
2813                 memcpy(new_array, *ea_inode_array,
2814                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2815                 kfree(*ea_inode_array);
2816                 *ea_inode_array = new_array;
2817         }
2818         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2819         return 0;
2820 }
2821
2822 /*
2823  * ext4_xattr_delete_inode()
2824  *
2825  * Free extended attribute resources associated with this inode. Traverse
2826  * all entries and decrement reference on any xattr inodes associated with this
2827  * inode. This is called immediately before an inode is freed. We have exclusive
2828  * access to the inode. If an orphan inode is deleted it will also release its
2829  * references on xattr block and xattr inodes.
2830  */
2831 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2832                             struct ext4_xattr_inode_array **ea_inode_array,
2833                             int extra_credits)
2834 {
2835         struct buffer_head *bh = NULL;
2836         struct ext4_xattr_ibody_header *header;
2837         struct ext4_iloc iloc = { .bh = NULL };
2838         struct ext4_xattr_entry *entry;
2839         struct inode *ea_inode;
2840         int error;
2841
2842         error = ext4_journal_ensure_credits(handle, extra_credits,
2843                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2844         if (error < 0) {
2845                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2846                 goto cleanup;
2847         }
2848
2849         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2850             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2851
2852                 error = ext4_get_inode_loc(inode, &iloc);
2853                 if (error) {
2854                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2855                         goto cleanup;
2856                 }
2857
2858                 error = ext4_journal_get_write_access(handle, inode->i_sb,
2859                                                 iloc.bh, EXT4_JTR_NONE);
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_ERR(inode, EIO,
2882                                                      "block %llu read error",
2883                                                      EXT4_I(inode)->i_file_acl);
2884                         }
2885                         bh = NULL;
2886                         goto cleanup;
2887                 }
2888                 error = ext4_xattr_check_block(inode, bh);
2889                 if (error)
2890                         goto cleanup;
2891
2892                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2893                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2894                              entry = EXT4_XATTR_NEXT(entry)) {
2895                                 if (!entry->e_value_inum)
2896                                         continue;
2897                                 error = ext4_xattr_inode_iget(inode,
2898                                               le32_to_cpu(entry->e_value_inum),
2899                                               le32_to_cpu(entry->e_hash),
2900                                               &ea_inode);
2901                                 if (error)
2902                                         continue;
2903                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2904                                               le32_to_cpu(entry->e_value_size));
2905                                 iput(ea_inode);
2906                         }
2907
2908                 }
2909
2910                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2911                                          extra_credits);
2912                 /*
2913                  * Update i_file_acl value in the same transaction that releases
2914                  * block.
2915                  */
2916                 EXT4_I(inode)->i_file_acl = 0;
2917                 error = ext4_mark_inode_dirty(handle, inode);
2918                 if (error) {
2919                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2920                                          error);
2921                         goto cleanup;
2922                 }
2923                 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2924         }
2925         error = 0;
2926 cleanup:
2927         brelse(iloc.bh);
2928         brelse(bh);
2929         return error;
2930 }
2931
2932 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2933 {
2934         int idx;
2935
2936         if (ea_inode_array == NULL)
2937                 return;
2938
2939         for (idx = 0; idx < ea_inode_array->count; ++idx)
2940                 iput(ea_inode_array->inodes[idx]);
2941         kfree(ea_inode_array);
2942 }
2943
2944 /*
2945  * ext4_xattr_block_cache_insert()
2946  *
2947  * Create a new entry in the extended attribute block cache, and insert
2948  * it unless such an entry is already in the cache.
2949  *
2950  * Returns 0, or a negative error number on failure.
2951  */
2952 static void
2953 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2954                               struct buffer_head *bh)
2955 {
2956         struct ext4_xattr_header *header = BHDR(bh);
2957         __u32 hash = le32_to_cpu(header->h_hash);
2958         int reusable = le32_to_cpu(header->h_refcount) <
2959                        EXT4_XATTR_REFCOUNT_MAX;
2960         int error;
2961
2962         if (!ea_block_cache)
2963                 return;
2964         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2965                                       bh->b_blocknr, reusable);
2966         if (error) {
2967                 if (error == -EBUSY)
2968                         ea_bdebug(bh, "already in cache");
2969         } else
2970                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2971 }
2972
2973 /*
2974  * ext4_xattr_cmp()
2975  *
2976  * Compare two extended attribute blocks for equality.
2977  *
2978  * Returns 0 if the blocks are equal, 1 if they differ, and
2979  * a negative error number on errors.
2980  */
2981 static int
2982 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2983                struct ext4_xattr_header *header2)
2984 {
2985         struct ext4_xattr_entry *entry1, *entry2;
2986
2987         entry1 = ENTRY(header1+1);
2988         entry2 = ENTRY(header2+1);
2989         while (!IS_LAST_ENTRY(entry1)) {
2990                 if (IS_LAST_ENTRY(entry2))
2991                         return 1;
2992                 if (entry1->e_hash != entry2->e_hash ||
2993                     entry1->e_name_index != entry2->e_name_index ||
2994                     entry1->e_name_len != entry2->e_name_len ||
2995                     entry1->e_value_size != entry2->e_value_size ||
2996                     entry1->e_value_inum != entry2->e_value_inum ||
2997                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2998                         return 1;
2999                 if (!entry1->e_value_inum &&
3000                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3001                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3002                            le32_to_cpu(entry1->e_value_size)))
3003                         return 1;
3004
3005                 entry1 = EXT4_XATTR_NEXT(entry1);
3006                 entry2 = EXT4_XATTR_NEXT(entry2);
3007         }
3008         if (!IS_LAST_ENTRY(entry2))
3009                 return 1;
3010         return 0;
3011 }
3012
3013 /*
3014  * ext4_xattr_block_cache_find()
3015  *
3016  * Find an identical extended attribute block.
3017  *
3018  * Returns a pointer to the block found, or NULL if such a block was
3019  * not found or an error occurred.
3020  */
3021 static struct buffer_head *
3022 ext4_xattr_block_cache_find(struct inode *inode,
3023                             struct ext4_xattr_header *header,
3024                             struct mb_cache_entry **pce)
3025 {
3026         __u32 hash = le32_to_cpu(header->h_hash);
3027         struct mb_cache_entry *ce;
3028         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3029
3030         if (!ea_block_cache)
3031                 return NULL;
3032         if (!header->h_hash)
3033                 return NULL;  /* never share */
3034         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3035         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3036         while (ce) {
3037                 struct buffer_head *bh;
3038
3039                 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3040                 if (IS_ERR(bh)) {
3041                         if (PTR_ERR(bh) == -ENOMEM)
3042                                 return NULL;
3043                         bh = NULL;
3044                         EXT4_ERROR_INODE(inode, "block %lu read error",
3045                                          (unsigned long)ce->e_value);
3046                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3047                         *pce = ce;
3048                         return bh;
3049                 }
3050                 brelse(bh);
3051                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3052         }
3053         return NULL;
3054 }
3055
3056 #define NAME_HASH_SHIFT 5
3057 #define VALUE_HASH_SHIFT 16
3058
3059 /*
3060  * ext4_xattr_hash_entry()
3061  *
3062  * Compute the hash of an extended attribute.
3063  */
3064 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3065                                     size_t value_count)
3066 {
3067         __u32 hash = 0;
3068
3069         while (name_len--) {
3070                 hash = (hash << NAME_HASH_SHIFT) ^
3071                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3072                        *name++;
3073         }
3074         while (value_count--) {
3075                 hash = (hash << VALUE_HASH_SHIFT) ^
3076                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3077                        le32_to_cpu(*value++);
3078         }
3079         return cpu_to_le32(hash);
3080 }
3081
3082 #undef NAME_HASH_SHIFT
3083 #undef VALUE_HASH_SHIFT
3084
3085 #define BLOCK_HASH_SHIFT 16
3086
3087 /*
3088  * ext4_xattr_rehash()
3089  *
3090  * Re-compute the extended attribute hash value after an entry has changed.
3091  */
3092 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3093 {
3094         struct ext4_xattr_entry *here;
3095         __u32 hash = 0;
3096
3097         here = ENTRY(header+1);
3098         while (!IS_LAST_ENTRY(here)) {
3099                 if (!here->e_hash) {
3100                         /* Block is not shared if an entry's hash value == 0 */
3101                         hash = 0;
3102                         break;
3103                 }
3104                 hash = (hash << BLOCK_HASH_SHIFT) ^
3105                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3106                        le32_to_cpu(here->e_hash);
3107                 here = EXT4_XATTR_NEXT(here);
3108         }
3109         header->h_hash = cpu_to_le32(hash);
3110 }
3111
3112 #undef BLOCK_HASH_SHIFT
3113
3114 #define HASH_BUCKET_BITS        10
3115
3116 struct mb_cache *
3117 ext4_xattr_create_cache(void)
3118 {
3119         return mb_cache_create(HASH_BUCKET_BITS);
3120 }
3121
3122 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3123 {
3124         if (cache)
3125                 mb_cache_destroy(cache);
3126 }
3127