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, EXT4_SB(sb)->s_sbh) == 0) {
 795                 ext4_set_feature_xattr(sb);
 796                 ext4_handle_dirty_super(handle, sb);
 797         }
 798 }
 799
 800 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 801 {
 802         struct ext4_iloc iloc = { .bh = NULL };
 803         struct buffer_head *bh = NULL;
 804         struct ext4_inode *raw_inode;
 805         struct ext4_xattr_ibody_header *header;
 806         struct ext4_xattr_entry *entry;
 807         qsize_t ea_inode_refs = 0;
 808         void *end;
 809         int ret;
 810
 811         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 812
 813         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 814                 ret = ext4_get_inode_loc(inode, &iloc);
 815                 if (ret)
 816                         goto out;
 817                 raw_inode = ext4_raw_inode(&iloc);
 818                 header = IHDR(inode, raw_inode);
 819                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 820                 ret = xattr_check_inode(inode, header, end);
 821                 if (ret)
 822                         goto out;
 823
 824                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 825                      entry = EXT4_XATTR_NEXT(entry))
 826                         if (entry->e_value_inum)
 827                                 ea_inode_refs++;
 828         }
 829
 830         if (EXT4_I(inode)->i_file_acl) {
 831                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 832                 if (IS_ERR(bh)) {
 833                         ret = PTR_ERR(bh);
 834                         bh = NULL;
 835                         goto out;
 836                 }
 837
 838                 ret = ext4_xattr_check_block(inode, bh);
 839                 if (ret)
 840                         goto out;
 841
 842                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 843                      entry = EXT4_XATTR_NEXT(entry))
 844                         if (entry->e_value_inum)
 845                                 ea_inode_refs++;
 846         }
 847         *usage = ea_inode_refs + 1;
 848         ret = 0;
 849 out:
 850         brelse(iloc.bh);
 851         brelse(bh);
 852         return ret;
 853 }
 854
 855 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 856 {
 857         struct super_block *sb = inode->i_sb;
 858         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 859                                     inode->i_blkbits);
 860         size_t mask = ~(cluster_size - 1);
 861
 862         return (length + cluster_size - 1) & mask;
 863 }
 864
 865 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 866 {
 867         int err;
 868
 869         err = dquot_alloc_inode(inode);
 870         if (err)
 871                 return err;
 872         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 873         if (err)
 874                 dquot_free_inode(inode);
 875         return err;
 876 }
 877
 878 static void ext4_xattr_inode_free_quota(struct inode *parent,
 879                                         struct inode *ea_inode,
 880                                         size_t len)
 881 {
 882         if (ea_inode &&
 883             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 884                 return;
 885         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 886         dquot_free_inode(parent);
 887 }
 888
 889 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 890                              struct buffer_head *block_bh, size_t value_len,
 891                              bool is_create)
 892 {
 893         int credits;
 894         int blocks;
 895
 896         /*
 897          * 1) Owner inode update
 898          * 2) Ref count update on old xattr block
 899          * 3) new xattr block
 900          * 4) block bitmap update for new xattr block
 901          * 5) group descriptor for new xattr block
 902          * 6) block bitmap update for old xattr block
 903          * 7) group descriptor for old block
 904          *
 905          * 6 & 7 can happen if we have two racing threads T_a and T_b
 906          * which are each trying to set an xattr on inodes I_a and I_b
 907          * which were both initially sharing an xattr block.
 908          */
 909         credits = 7;
 910
 911         /* Quota updates. */
 912         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 913
 914         /*
 915          * In case of inline data, we may push out the data to a block,
 916          * so we need to reserve credits for this eventuality
 917          */
 918         if (inode && ext4_has_inline_data(inode))
 919                 credits += ext4_writepage_trans_blocks(inode) + 1;
 920
 921         /* We are done if ea_inode feature is not enabled. */
 922         if (!ext4_has_feature_ea_inode(sb))
 923                 return credits;
 924
 925         /* New ea_inode, inode map, block bitmap, group descriptor. */
 926         credits += 4;
 927
 928         /* Data blocks. */
 929         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 930
 931         /* Indirection block or one level of extent tree. */
 932         blocks += 1;
 933
 934         /* Block bitmap and group descriptor updates for each block. */
 935         credits += blocks * 2;
 936
 937         /* Blocks themselves. */
 938         credits += blocks;
 939
 940         if (!is_create) {
 941                 /* Dereference ea_inode holding old xattr value.
 942                  * Old ea_inode, inode map, block bitmap, group descriptor.
 943                  */
 944                 credits += 4;
 945
 946                 /* Data blocks for old ea_inode. */
 947                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 948
 949                 /* Indirection block or one level of extent tree for old
 950                  * ea_inode.
 951                  */
 952                 blocks += 1;
 953
 954                 /* Block bitmap and group descriptor updates for each block. */
 955                 credits += blocks * 2;
 956         }
 957
 958         /* We may need to clone the existing xattr block in which case we need
 959          * to increment ref counts for existing ea_inodes referenced by it.
 960          */
 961         if (block_bh) {
 962                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 963
 964                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 965                         if (entry->e_value_inum)
 966                                 /* Ref count update on ea_inode. */
 967                                 credits += 1;
 968         }
 969         return credits;
 970 }
 971
 972 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 973                                        int ref_change)
 974 {
 975         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
 976         struct ext4_iloc iloc;
 977         s64 ref_count;
 978         u32 hash;
 979         int ret;
 980
 981         inode_lock(ea_inode);
 982
 983         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
 984         if (ret)
 985                 goto out;
 986
 987         ref_count = ext4_xattr_inode_get_ref(ea_inode);
 988         ref_count += ref_change;
 989         ext4_xattr_inode_set_ref(ea_inode, ref_count);
 990
 991         if (ref_change > 0) {
 992                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
 993                           ea_inode->i_ino, ref_count);
 994
 995                 if (ref_count == 1) {
 996                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
 997                                   ea_inode->i_ino, ea_inode->i_nlink);
 998
 999                         set_nlink(ea_inode, 1);
1000                         ext4_orphan_del(handle, ea_inode);
1001
1002                         if (ea_inode_cache) {
1003                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1004                                 mb_cache_entry_create(ea_inode_cache,
1005                                                       GFP_NOFS, hash,
1006                                                       ea_inode->i_ino,
1007                                                       true /* reusable */);
1008                         }
1009                 }
1010         } else {
1011                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1012                           ea_inode->i_ino, ref_count);
1013
1014                 if (ref_count == 0) {
1015                         WARN_ONCE(ea_inode->i_nlink != 1,
1016                                   "EA inode %lu i_nlink=%u",
1017                                   ea_inode->i_ino, ea_inode->i_nlink);
1018
1019                         clear_nlink(ea_inode);
1020                         ext4_orphan_add(handle, ea_inode);
1021
1022                         if (ea_inode_cache) {
1023                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1024                                 mb_cache_entry_delete(ea_inode_cache, hash,
1025                                                       ea_inode->i_ino);
1026                         }
1027                 }
1028         }
1029
1030         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1031         if (ret)
1032                 ext4_warning_inode(ea_inode,
1033                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1034 out:
1035         inode_unlock(ea_inode);
1036         return ret;
1037 }
1038
1039 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1040 {
1041         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1042 }
1043
1044 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1045 {
1046         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1047 }
1048
1049 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1050                                         struct ext4_xattr_entry *first)
1051 {
1052         struct inode *ea_inode;
1053         struct ext4_xattr_entry *entry;
1054         struct ext4_xattr_entry *failed_entry;
1055         unsigned int ea_ino;
1056         int err, saved_err;
1057
1058         for (entry = first; !IS_LAST_ENTRY(entry);
1059              entry = EXT4_XATTR_NEXT(entry)) {
1060                 if (!entry->e_value_inum)
1061                         continue;
1062                 ea_ino = le32_to_cpu(entry->e_value_inum);
1063                 err = ext4_xattr_inode_iget(parent, ea_ino,
1064                                             le32_to_cpu(entry->e_hash),
1065                                             &ea_inode);
1066                 if (err)
1067                         goto cleanup;
1068                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1069                 if (err) {
1070                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1071                         iput(ea_inode);
1072                         goto cleanup;
1073                 }
1074                 iput(ea_inode);
1075         }
1076         return 0;
1077
1078 cleanup:
1079         saved_err = err;
1080         failed_entry = entry;
1081
1082         for (entry = first; entry != failed_entry;
1083              entry = EXT4_XATTR_NEXT(entry)) {
1084                 if (!entry->e_value_inum)
1085                         continue;
1086                 ea_ino = le32_to_cpu(entry->e_value_inum);
1087                 err = ext4_xattr_inode_iget(parent, ea_ino,
1088                                             le32_to_cpu(entry->e_hash),
1089                                             &ea_inode);
1090                 if (err) {
1091                         ext4_warning(parent->i_sb,
1092                                      "cleanup ea_ino %u iget error %d", ea_ino,
1093                                      err);
1094                         continue;
1095                 }
1096                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1097                 if (err)
1098                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1099                                            err);
1100                 iput(ea_inode);
1101         }
1102         return saved_err;
1103 }
1104
1105 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1106                         struct buffer_head *bh, bool block_csum, bool dirty)
1107 {
1108         int error;
1109
1110         if (bh && dirty) {
1111                 if (block_csum)
1112                         ext4_xattr_block_csum_set(inode, bh);
1113                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1114                 if (error) {
1115                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1116                                      error);
1117                         return error;
1118                 }
1119         }
1120         return 0;
1121 }
1122
1123 static void
1124 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1125                              struct buffer_head *bh,
1126                              struct ext4_xattr_entry *first, bool block_csum,
1127                              struct ext4_xattr_inode_array **ea_inode_array,
1128                              int extra_credits, bool skip_quota)
1129 {
1130         struct inode *ea_inode;
1131         struct ext4_xattr_entry *entry;
1132         bool dirty = false;
1133         unsigned int ea_ino;
1134         int err;
1135         int credits;
1136
1137         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1138         credits = 2 + extra_credits;
1139
1140         for (entry = first; !IS_LAST_ENTRY(entry);
1141              entry = EXT4_XATTR_NEXT(entry)) {
1142                 if (!entry->e_value_inum)
1143                         continue;
1144                 ea_ino = le32_to_cpu(entry->e_value_inum);
1145                 err = ext4_xattr_inode_iget(parent, ea_ino,
1146                                             le32_to_cpu(entry->e_hash),
1147                                             &ea_inode);
1148                 if (err)
1149                         continue;
1150
1151                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1152                 if (err) {
1153                         ext4_warning_inode(ea_inode,
1154                                            "Expand inode array err=%d", err);
1155                         iput(ea_inode);
1156                         continue;
1157                 }
1158
1159                 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1160                         ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1161                         ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1162                                               dirty));
1163                 if (err < 0) {
1164                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1165                                            err);
1166                         continue;
1167                 }
1168                 if (err > 0) {
1169                         err = ext4_journal_get_write_access(handle, bh);
1170                         if (err) {
1171                                 ext4_warning_inode(ea_inode,
1172                                                 "Re-get write access err=%d",
1173                                                 err);
1174                                 continue;
1175                         }
1176                 }
1177
1178                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1179                 if (err) {
1180                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1181                                            err);
1182                         continue;
1183                 }
1184
1185                 if (!skip_quota)
1186                         ext4_xattr_inode_free_quota(parent, ea_inode,
1187                                               le32_to_cpu(entry->e_value_size));
1188
1189                 /*
1190                  * Forget about ea_inode within the same transaction that
1191                  * decrements the ref count. This avoids duplicate decrements in
1192                  * case the rest of the work spills over to subsequent
1193                  * transactions.
1194                  */
1195                 entry->e_value_inum = 0;
1196                 entry->e_value_size = 0;
1197
1198                 dirty = true;
1199         }
1200
1201         if (dirty) {
1202                 /*
1203                  * Note that we are deliberately skipping csum calculation for
1204                  * the final update because we do not expect any journal
1205                  * restarts until xattr block is freed.
1206                  */
1207
1208                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1209                 if (err)
1210                         ext4_warning_inode(parent,
1211                                            "handle dirty metadata err=%d", err);
1212         }
1213 }
1214
1215 /*
1216  * Release the xattr block BH: If the reference count is > 1, decrement it;
1217  * otherwise free the block.
1218  */
1219 static void
1220 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1221                          struct buffer_head *bh,
1222                          struct ext4_xattr_inode_array **ea_inode_array,
1223                          int extra_credits)
1224 {
1225         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1226         u32 hash, ref;
1227         int error = 0;
1228
1229         BUFFER_TRACE(bh, "get_write_access");
1230         error = ext4_journal_get_write_access(handle, bh);
1231         if (error)
1232                 goto out;
1233
1234         lock_buffer(bh);
1235         hash = le32_to_cpu(BHDR(bh)->h_hash);
1236         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1237         if (ref == 1) {
1238                 ea_bdebug(bh, "refcount now=0; freeing");
1239                 /*
1240                  * This must happen under buffer lock for
1241                  * ext4_xattr_block_set() to reliably detect freed block
1242                  */
1243                 if (ea_block_cache)
1244                         mb_cache_entry_delete(ea_block_cache, hash,
1245                                               bh->b_blocknr);
1246                 get_bh(bh);
1247                 unlock_buffer(bh);
1248
1249                 if (ext4_has_feature_ea_inode(inode->i_sb))
1250                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1251                                                      BFIRST(bh),
1252                                                      true /* block_csum */,
1253                                                      ea_inode_array,
1254                                                      extra_credits,
1255                                                      true /* skip_quota */);
1256                 ext4_free_blocks(handle, inode, bh, 0, 1,
1257                                  EXT4_FREE_BLOCKS_METADATA |
1258                                  EXT4_FREE_BLOCKS_FORGET);
1259         } else {
1260                 ref--;
1261                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1262                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1263                         struct mb_cache_entry *ce;
1264
1265                         if (ea_block_cache) {
1266                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1267                                                         bh->b_blocknr);
1268                                 if (ce) {
1269                                         ce->e_reusable = 1;
1270                                         mb_cache_entry_put(ea_block_cache, ce);
1271                                 }
1272                         }
1273                 }
1274
1275                 ext4_xattr_block_csum_set(inode, bh);
1276                 /*
1277                  * Beware of this ugliness: Releasing of xattr block references
1278                  * from different inodes can race and so we have to protect
1279                  * from a race where someone else frees the block (and releases
1280                  * its journal_head) before we are done dirtying the buffer. In
1281                  * nojournal mode this race is harmless and we actually cannot
1282                  * call ext4_handle_dirty_metadata() with locked buffer as
1283                  * that function can call sync_dirty_buffer() so for that case
1284                  * we handle the dirtying after unlocking the buffer.
1285                  */
1286                 if (ext4_handle_valid(handle))
1287                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1288                 unlock_buffer(bh);
1289                 if (!ext4_handle_valid(handle))
1290                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1291                 if (IS_SYNC(inode))
1292                         ext4_handle_sync(handle);
1293                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1294                 ea_bdebug(bh, "refcount now=%d; releasing",
1295                           le32_to_cpu(BHDR(bh)->h_refcount));
1296         }
1297 out:
1298         ext4_std_error(inode->i_sb, error);
1299         return;
1300 }
1301
1302 /*
1303  * Find the available free space for EAs. This also returns the total number of
1304  * bytes used by EA entries.
1305  */
1306 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1307                                     size_t *min_offs, void *base, int *total)
1308 {
1309         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1310                 if (!last->e_value_inum && last->e_value_size) {
1311                         size_t offs = le16_to_cpu(last->e_value_offs);
1312                         if (offs < *min_offs)
1313                                 *min_offs = offs;
1314                 }
1315                 if (total)
1316                         *total += EXT4_XATTR_LEN(last->e_name_len);
1317         }
1318         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1319 }
1320
1321 /*
1322  * Write the value of the EA in an inode.
1323  */
1324 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1325                                   const void *buf, int bufsize)
1326 {
1327         struct buffer_head *bh = NULL;
1328         unsigned long block = 0;
1329         int blocksize = ea_inode->i_sb->s_blocksize;
1330         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1331         int csize, wsize = 0;
1332         int ret = 0, ret2 = 0;
1333         int retries = 0;
1334
1335 retry:
1336         while (ret >= 0 && ret < max_blocks) {
1337                 struct ext4_map_blocks map;
1338                 map.m_lblk = block += ret;
1339                 map.m_len = max_blocks -= ret;
1340
1341                 ret = ext4_map_blocks(handle, ea_inode, &map,
1342                                       EXT4_GET_BLOCKS_CREATE);
1343                 if (ret <= 0) {
1344                         ext4_mark_inode_dirty(handle, ea_inode);
1345                         if (ret == -ENOSPC &&
1346                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1347                                 ret = 0;
1348                                 goto retry;
1349                         }
1350                         break;
1351                 }
1352         }
1353
1354         if (ret < 0)
1355                 return ret;
1356
1357         block = 0;
1358         while (wsize < bufsize) {
1359                 brelse(bh);
1360                 csize = (bufsize - wsize) > blocksize ? blocksize :
1361                                                                 bufsize - wsize;
1362                 bh = ext4_getblk(handle, ea_inode, block, 0);
1363                 if (IS_ERR(bh))
1364                         return PTR_ERR(bh);
1365                 if (!bh) {
1366                         WARN_ON_ONCE(1);
1367                         EXT4_ERROR_INODE(ea_inode,
1368                                          "ext4_getblk() return bh = NULL");
1369                         return -EFSCORRUPTED;
1370                 }
1371                 ret = ext4_journal_get_write_access(handle, bh);
1372                 if (ret)
1373                         goto out;
1374
1375                 memcpy(bh->b_data, buf, csize);
1376                 set_buffer_uptodate(bh);
1377                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1378
1379                 buf += csize;
1380                 wsize += csize;
1381                 block += 1;
1382         }
1383
1384         inode_lock(ea_inode);
1385         i_size_write(ea_inode, wsize);
1386         ext4_update_i_disksize(ea_inode, wsize);
1387         inode_unlock(ea_inode);
1388
1389         ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1390         if (unlikely(ret2 && !ret))
1391                 ret = ret2;
1392
1393 out:
1394         brelse(bh);
1395
1396         return ret;
1397 }
1398
1399 /*
1400  * Create an inode to store the value of a large EA.
1401  */
1402 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1403                                              struct inode *inode, u32 hash)
1404 {
1405         struct inode *ea_inode = NULL;
1406         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1407         int err;
1408
1409         /*
1410          * Let the next inode be the goal, so we try and allocate the EA inode
1411          * in the same group, or nearby one.
1412          */
1413         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1414                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1415                                   EXT4_EA_INODE_FL);
1416         if (!IS_ERR(ea_inode)) {
1417                 ea_inode->i_op = &ext4_file_inode_operations;
1418                 ea_inode->i_fop = &ext4_file_operations;
1419                 ext4_set_aops(ea_inode);
1420                 ext4_xattr_inode_set_class(ea_inode);
1421                 unlock_new_inode(ea_inode);
1422                 ext4_xattr_inode_set_ref(ea_inode, 1);
1423                 ext4_xattr_inode_set_hash(ea_inode, hash);
1424                 err = ext4_mark_inode_dirty(handle, ea_inode);
1425                 if (!err)
1426                         err = ext4_inode_attach_jinode(ea_inode);
1427                 if (err) {
1428                         iput(ea_inode);
1429                         return ERR_PTR(err);
1430                 }
1431
1432                 /*
1433                  * Xattr inodes are shared therefore quota charging is performed
1434                  * at a higher level.
1435                  */
1436                 dquot_free_inode(ea_inode);
1437                 dquot_drop(ea_inode);
1438                 inode_lock(ea_inode);
1439                 ea_inode->i_flags |= S_NOQUOTA;
1440                 inode_unlock(ea_inode);
1441         }
1442
1443         return ea_inode;
1444 }
1445
1446 static struct inode *
1447 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1448                             size_t value_len, u32 hash)
1449 {
1450         struct inode *ea_inode;
1451         struct mb_cache_entry *ce;
1452         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1453         void *ea_data;
1454
1455         if (!ea_inode_cache)
1456                 return NULL;
1457
1458         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1459         if (!ce)
1460                 return NULL;
1461
1462         WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1463                      !(current->flags & PF_MEMALLOC_NOFS));
1464
1465         ea_data = kvmalloc(value_len, GFP_KERNEL);
1466         if (!ea_data) {
1467                 mb_cache_entry_put(ea_inode_cache, ce);
1468                 return NULL;
1469         }
1470
1471         while (ce) {
1472                 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1473                                      EXT4_IGET_NORMAL);
1474                 if (!IS_ERR(ea_inode) &&
1475                     !is_bad_inode(ea_inode) &&
1476                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1477                     i_size_read(ea_inode) == value_len &&
1478                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1479                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1480                                                     value_len) &&
1481                     !memcmp(value, ea_data, value_len)) {
1482                         mb_cache_entry_touch(ea_inode_cache, ce);
1483                         mb_cache_entry_put(ea_inode_cache, ce);
1484                         kvfree(ea_data);
1485                         return ea_inode;
1486                 }
1487
1488                 if (!IS_ERR(ea_inode))
1489                         iput(ea_inode);
1490                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1491         }
1492         kvfree(ea_data);
1493         return NULL;
1494 }
1495
1496 /*
1497  * Add value of the EA in an inode.
1498  */
1499 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1500                                           const void *value, size_t value_len,
1501                                           struct inode **ret_inode)
1502 {
1503         struct inode *ea_inode;
1504         u32 hash;
1505         int err;
1506
1507         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1508         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1509         if (ea_inode) {
1510                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1511                 if (err) {
1512                         iput(ea_inode);
1513                         return err;
1514                 }
1515
1516                 *ret_inode = ea_inode;
1517                 return 0;
1518         }
1519
1520         /* Create an inode for the EA value */
1521         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1522         if (IS_ERR(ea_inode))
1523                 return PTR_ERR(ea_inode);
1524
1525         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1526         if (err) {
1527                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1528                 iput(ea_inode);
1529                 return err;
1530         }
1531
1532         if (EA_INODE_CACHE(inode))
1533                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1534                                       ea_inode->i_ino, true /* reusable */);
1535
1536         *ret_inode = ea_inode;
1537         return 0;
1538 }
1539
1540 /*
1541  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1542  * feature is enabled.
1543  */
1544 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1545
1546 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1547                                 struct ext4_xattr_search *s,
1548                                 handle_t *handle, struct inode *inode,
1549                                 bool is_block)
1550 {
1551         struct ext4_xattr_entry *last, *next;
1552         struct ext4_xattr_entry *here = s->here;
1553         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1554         int in_inode = i->in_inode;
1555         struct inode *old_ea_inode = NULL;
1556         struct inode *new_ea_inode = NULL;
1557         size_t old_size, new_size;
1558         int ret;
1559
1560         /* Space used by old and new values. */
1561         old_size = (!s->not_found && !here->e_value_inum) ?
1562                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1563         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1564
1565         /*
1566          * Optimization for the simple case when old and new values have the
1567          * same padded sizes. Not applicable if external inodes are involved.
1568          */
1569         if (new_size && new_size == old_size) {
1570                 size_t offs = le16_to_cpu(here->e_value_offs);
1571                 void *val = s->base + offs;
1572
1573                 here->e_value_size = cpu_to_le32(i->value_len);
1574                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1575                         memset(val, 0, new_size);
1576                 } else {
1577                         memcpy(val, i->value, i->value_len);
1578                         /* Clear padding bytes. */
1579                         memset(val + i->value_len, 0, new_size - i->value_len);
1580                 }
1581                 goto update_hash;
1582         }
1583
1584         /* Compute min_offs and last. */
1585         last = s->first;
1586         for (; !IS_LAST_ENTRY(last); last = next) {
1587                 next = EXT4_XATTR_NEXT(last);
1588                 if ((void *)next >= s->end) {
1589                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1590                         ret = -EFSCORRUPTED;
1591                         goto out;
1592                 }
1593                 if (!last->e_value_inum && last->e_value_size) {
1594                         size_t offs = le16_to_cpu(last->e_value_offs);
1595                         if (offs < min_offs)
1596                                 min_offs = offs;
1597                 }
1598         }
1599
1600         /* Check whether we have enough space. */
1601         if (i->value) {
1602                 size_t free;
1603
1604                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1605                 if (!s->not_found)
1606                         free += EXT4_XATTR_LEN(name_len) + old_size;
1607
1608                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1609                         ret = -ENOSPC;
1610                         goto out;
1611                 }
1612
1613                 /*
1614                  * If storing the value in an external inode is an option,
1615                  * reserve space for xattr entries/names in the external
1616                  * attribute block so that a long value does not occupy the
1617                  * whole space and prevent futher entries being added.
1618                  */
1619                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1620                     new_size && is_block &&
1621                     (min_offs + old_size - new_size) <
1622                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1623                         ret = -ENOSPC;
1624                         goto out;
1625                 }
1626         }
1627
1628         /*
1629          * Getting access to old and new ea inodes is subject to failures.
1630          * Finish that work before doing any modifications to the xattr data.
1631          */
1632         if (!s->not_found && here->e_value_inum) {
1633                 ret = ext4_xattr_inode_iget(inode,
1634                                             le32_to_cpu(here->e_value_inum),
1635                                             le32_to_cpu(here->e_hash),
1636                                             &old_ea_inode);
1637                 if (ret) {
1638                         old_ea_inode = NULL;
1639                         goto out;
1640                 }
1641         }
1642         if (i->value && in_inode) {
1643                 WARN_ON_ONCE(!i->value_len);
1644
1645                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1646                 if (ret)
1647                         goto out;
1648
1649                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1650                                                      i->value_len,
1651                                                      &new_ea_inode);
1652                 if (ret) {
1653                         new_ea_inode = NULL;
1654                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1655                         goto out;
1656                 }
1657         }
1658
1659         if (old_ea_inode) {
1660                 /* We are ready to release ref count on the old_ea_inode. */
1661                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1662                 if (ret) {
1663                         /* Release newly required ref count on new_ea_inode. */
1664                         if (new_ea_inode) {
1665                                 int err;
1666
1667                                 err = ext4_xattr_inode_dec_ref(handle,
1668                                                                new_ea_inode);
1669                                 if (err)
1670                                         ext4_warning_inode(new_ea_inode,
1671                                                   "dec ref new_ea_inode err=%d",
1672                                                   err);
1673                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1674                                                             i->value_len);
1675                         }
1676                         goto out;
1677                 }
1678
1679                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1680                                             le32_to_cpu(here->e_value_size));
1681         }
1682
1683         /* No failures allowed past this point. */
1684
1685         if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1686                 /* Remove the old value. */
1687                 void *first_val = s->base + min_offs;
1688                 size_t offs = le16_to_cpu(here->e_value_offs);
1689                 void *val = s->base + offs;
1690
1691                 memmove(first_val + old_size, first_val, val - first_val);
1692                 memset(first_val, 0, old_size);
1693                 min_offs += old_size;
1694
1695                 /* Adjust all value offsets. */
1696                 last = s->first;
1697                 while (!IS_LAST_ENTRY(last)) {
1698                         size_t o = le16_to_cpu(last->e_value_offs);
1699
1700                         if (!last->e_value_inum &&
1701                             last->e_value_size && o < offs)
1702                                 last->e_value_offs = cpu_to_le16(o + old_size);
1703                         last = EXT4_XATTR_NEXT(last);
1704                 }
1705         }
1706
1707         if (!i->value) {
1708                 /* Remove old name. */
1709                 size_t size = EXT4_XATTR_LEN(name_len);
1710
1711                 last = ENTRY((void *)last - size);
1712                 memmove(here, (void *)here + size,
1713                         (void *)last - (void *)here + sizeof(__u32));
1714                 memset(last, 0, size);
1715         } else if (s->not_found) {
1716                 /* Insert new name. */
1717                 size_t size = EXT4_XATTR_LEN(name_len);
1718                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1719
1720                 memmove((void *)here + size, here, rest);
1721                 memset(here, 0, size);
1722                 here->e_name_index = i->name_index;
1723                 here->e_name_len = name_len;
1724                 memcpy(here->e_name, i->name, name_len);
1725         } else {
1726                 /* This is an update, reset value info. */
1727                 here->e_value_inum = 0;
1728                 here->e_value_offs = 0;
1729                 here->e_value_size = 0;
1730         }
1731
1732         if (i->value) {
1733                 /* Insert new value. */
1734                 if (in_inode) {
1735                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1736                 } else if (i->value_len) {
1737                         void *val = s->base + min_offs - new_size;
1738
1739                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1740                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1741                                 memset(val, 0, new_size);
1742                         } else {
1743                                 memcpy(val, i->value, i->value_len);
1744                                 /* Clear padding bytes. */
1745                                 memset(val + i->value_len, 0,
1746                                        new_size - i->value_len);
1747                         }
1748                 }
1749                 here->e_value_size = cpu_to_le32(i->value_len);
1750         }
1751
1752 update_hash:
1753         if (i->value) {
1754                 __le32 hash = 0;
1755
1756                 /* Entry hash calculation. */
1757                 if (in_inode) {
1758                         __le32 crc32c_hash;
1759
1760                         /*
1761                          * Feed crc32c hash instead of the raw value for entry
1762                          * hash calculation. This is to avoid walking
1763                          * potentially long value buffer again.
1764                          */
1765                         crc32c_hash = cpu_to_le32(
1766                                        ext4_xattr_inode_get_hash(new_ea_inode));
1767                         hash = ext4_xattr_hash_entry(here->e_name,
1768                                                      here->e_name_len,
1769                                                      &crc32c_hash, 1);
1770                 } else if (is_block) {
1771                         __le32 *value = s->base + le16_to_cpu(
1772                                                         here->e_value_offs);
1773
1774                         hash = ext4_xattr_hash_entry(here->e_name,
1775                                                      here->e_name_len, value,
1776                                                      new_size >> 2);
1777                 }
1778                 here->e_hash = hash;
1779         }
1780
1781         if (is_block)
1782                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1783
1784         ret = 0;
1785 out:
1786         iput(old_ea_inode);
1787         iput(new_ea_inode);
1788         return ret;
1789 }
1790
1791 struct ext4_xattr_block_find {
1792         struct ext4_xattr_search s;
1793         struct buffer_head *bh;
1794 };
1795
1796 static int
1797 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1798                       struct ext4_xattr_block_find *bs)
1799 {
1800         struct super_block *sb = inode->i_sb;
1801         int error;
1802
1803         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1804                   i->name_index, i->name, i->value, (long)i->value_len);
1805
1806         if (EXT4_I(inode)->i_file_acl) {
1807                 /* The inode already has an extended attribute block. */
1808                 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1809                 if (IS_ERR(bs->bh)) {
1810                         error = PTR_ERR(bs->bh);
1811                         bs->bh = NULL;
1812                         return error;
1813                 }
1814                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1815                         atomic_read(&(bs->bh->b_count)),
1816                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1817                 error = ext4_xattr_check_block(inode, bs->bh);
1818                 if (error)
1819                         return error;
1820                 /* Find the named attribute. */
1821                 bs->s.base = BHDR(bs->bh);
1822                 bs->s.first = BFIRST(bs->bh);
1823                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1824                 bs->s.here = bs->s.first;
1825                 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1826                                          i->name_index, i->name, 1);
1827                 if (error && error != -ENODATA)
1828                         return error;
1829                 bs->s.not_found = error;
1830         }
1831         return 0;
1832 }
1833
1834 static int
1835 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1836                      struct ext4_xattr_info *i,
1837                      struct ext4_xattr_block_find *bs)
1838 {
1839         struct super_block *sb = inode->i_sb;
1840         struct buffer_head *new_bh = NULL;
1841         struct ext4_xattr_search s_copy = bs->s;
1842         struct ext4_xattr_search *s = &s_copy;
1843         struct mb_cache_entry *ce = NULL;
1844         int error = 0;
1845         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1846         struct inode *ea_inode = NULL, *tmp_inode;
1847         size_t old_ea_inode_quota = 0;
1848         unsigned int ea_ino;
1849
1850
1851 #define header(x) ((struct ext4_xattr_header *)(x))
1852
1853         if (s->base) {
1854                 BUFFER_TRACE(bs->bh, "get_write_access");
1855                 error = ext4_journal_get_write_access(handle, bs->bh);
1856                 if (error)
1857                         goto cleanup;
1858                 lock_buffer(bs->bh);
1859
1860                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1861                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1862
1863                         /*
1864                          * This must happen under buffer lock for
1865                          * ext4_xattr_block_set() to reliably detect modified
1866                          * block
1867                          */
1868                         if (ea_block_cache)
1869                                 mb_cache_entry_delete(ea_block_cache, hash,
1870                                                       bs->bh->b_blocknr);
1871                         ea_bdebug(bs->bh, "modifying in-place");
1872                         error = ext4_xattr_set_entry(i, s, handle, inode,
1873                                                      true /* is_block */);
1874                         ext4_xattr_block_csum_set(inode, bs->bh);
1875                         unlock_buffer(bs->bh);
1876                         if (error == -EFSCORRUPTED)
1877                                 goto bad_block;
1878                         if (!error)
1879                                 error = ext4_handle_dirty_metadata(handle,
1880                                                                    inode,
1881                                                                    bs->bh);
1882                         if (error)
1883                                 goto cleanup;
1884                         goto inserted;
1885                 } else {
1886                         int offset = (char *)s->here - bs->bh->b_data;
1887
1888                         unlock_buffer(bs->bh);
1889                         ea_bdebug(bs->bh, "cloning");
1890                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1891                         error = -ENOMEM;
1892                         if (s->base == NULL)
1893                                 goto cleanup;
1894                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1895                         s->first = ENTRY(header(s->base)+1);
1896                         header(s->base)->h_refcount = cpu_to_le32(1);
1897                         s->here = ENTRY(s->base + offset);
1898                         s->end = s->base + bs->bh->b_size;
1899
1900                         /*
1901                          * If existing entry points to an xattr inode, we need
1902                          * to prevent ext4_xattr_set_entry() from decrementing
1903                          * ref count on it because the reference belongs to the
1904                          * original block. In this case, make the entry look
1905                          * like it has an empty value.
1906                          */
1907                         if (!s->not_found && s->here->e_value_inum) {
1908                                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1909                                 error = ext4_xattr_inode_iget(inode, ea_ino,
1910                                               le32_to_cpu(s->here->e_hash),
1911                                               &tmp_inode);
1912                                 if (error)
1913                                         goto cleanup;
1914
1915                                 if (!ext4_test_inode_state(tmp_inode,
1916                                                 EXT4_STATE_LUSTRE_EA_INODE)) {
1917                                         /*
1918                                          * Defer quota free call for previous
1919                                          * inode until success is guaranteed.
1920                                          */
1921                                         old_ea_inode_quota = le32_to_cpu(
1922                                                         s->here->e_value_size);
1923                                 }
1924                                 iput(tmp_inode);
1925
1926                                 s->here->e_value_inum = 0;
1927                                 s->here->e_value_size = 0;
1928                         }
1929                 }
1930         } else {
1931                 /* Allocate a buffer where we construct the new block. */
1932                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1933                 /* assert(header == s->base) */
1934                 error = -ENOMEM;
1935                 if (s->base == NULL)
1936                         goto cleanup;
1937                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1938                 header(s->base)->h_blocks = cpu_to_le32(1);
1939                 header(s->base)->h_refcount = cpu_to_le32(1);
1940                 s->first = ENTRY(header(s->base)+1);
1941                 s->here = ENTRY(header(s->base)+1);
1942                 s->end = s->base + sb->s_blocksize;
1943         }
1944
1945         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1946         if (error == -EFSCORRUPTED)
1947                 goto bad_block;
1948         if (error)
1949                 goto cleanup;
1950
1951         if (i->value && s->here->e_value_inum) {
1952                 /*
1953                  * A ref count on ea_inode has been taken as part of the call to
1954                  * ext4_xattr_set_entry() above. We would like to drop this
1955                  * extra ref but we have to wait until the xattr block is
1956                  * initialized and has its own ref count on the ea_inode.
1957                  */
1958                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1959                 error = ext4_xattr_inode_iget(inode, ea_ino,
1960                                               le32_to_cpu(s->here->e_hash),
1961                                               &ea_inode);
1962                 if (error) {
1963                         ea_inode = NULL;
1964                         goto cleanup;
1965                 }
1966         }
1967
1968 inserted:
1969         if (!IS_LAST_ENTRY(s->first)) {
1970                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1971                                                      &ce);
1972                 if (new_bh) {
1973                         /* We found an identical block in the cache. */
1974                         if (new_bh == bs->bh)
1975                                 ea_bdebug(new_bh, "keeping");
1976                         else {
1977                                 u32 ref;
1978
1979                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
1980
1981                                 /* The old block is released after updating
1982                                    the inode. */
1983                                 error = dquot_alloc_block(inode,
1984                                                 EXT4_C2B(EXT4_SB(sb), 1));
1985                                 if (error)
1986                                         goto cleanup;
1987                                 BUFFER_TRACE(new_bh, "get_write_access");
1988                                 error = ext4_journal_get_write_access(handle,
1989                                                                       new_bh);
1990                                 if (error)
1991                                         goto cleanup_dquot;
1992                                 lock_buffer(new_bh);
1993                                 /*
1994                                  * We have to be careful about races with
1995                                  * freeing, rehashing or adding references to
1996                                  * xattr block. Once we hold buffer lock xattr
1997                                  * block's state is stable so we can check
1998                                  * whether the block got freed / rehashed or
1999                                  * not.  Since we unhash mbcache entry under
2000                                  * buffer lock when freeing / rehashing xattr
2001                                  * block, checking whether entry is still
2002                                  * hashed is reliable. Same rules hold for
2003                                  * e_reusable handling.
2004                                  */
2005                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2006                                     !ce->e_reusable) {
2007                                         /*
2008                                          * Undo everything and check mbcache
2009                                          * again.
2010                                          */
2011                                         unlock_buffer(new_bh);
2012                                         dquot_free_block(inode,
2013                                                          EXT4_C2B(EXT4_SB(sb),
2014                                                                   1));
2015                                         brelse(new_bh);
2016                                         mb_cache_entry_put(ea_block_cache, ce);
2017                                         ce = NULL;
2018                                         new_bh = NULL;
2019                                         goto inserted;
2020                                 }
2021                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2022                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2023                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2024                                         ce->e_reusable = 0;
2025                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2026                                           ref);
2027                                 ext4_xattr_block_csum_set(inode, new_bh);
2028                                 unlock_buffer(new_bh);
2029                                 error = ext4_handle_dirty_metadata(handle,
2030                                                                    inode,
2031                                                                    new_bh);
2032                                 if (error)
2033                                         goto cleanup_dquot;
2034                         }
2035                         mb_cache_entry_touch(ea_block_cache, ce);
2036                         mb_cache_entry_put(ea_block_cache, ce);
2037                         ce = NULL;
2038                 } else if (bs->bh && s->base == bs->bh->b_data) {
2039                         /* We were modifying this block in-place. */
2040                         ea_bdebug(bs->bh, "keeping this block");
2041                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2042                         new_bh = bs->bh;
2043                         get_bh(new_bh);
2044                 } else {
2045                         /* We need to allocate a new block */
2046                         ext4_fsblk_t goal, block;
2047
2048                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2049
2050                         goal = ext4_group_first_block_no(sb,
2051                                                 EXT4_I(inode)->i_block_group);
2052
2053                         /* non-extent files can't have physical blocks past 2^32 */
2054                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2055                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2056
2057                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2058                                                      NULL, &error);
2059                         if (error)
2060                                 goto cleanup;
2061
2062                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2063                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2064
2065                         ea_idebug(inode, "creating block %llu",
2066                                   (unsigned long long)block);
2067
2068                         new_bh = sb_getblk(sb, block);
2069                         if (unlikely(!new_bh)) {
2070                                 error = -ENOMEM;
2071 getblk_failed:
2072                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2073                                                  EXT4_FREE_BLOCKS_METADATA);
2074                                 goto cleanup;
2075                         }
2076                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2077                                                       ENTRY(header(s->base)+1));
2078                         if (error)
2079                                 goto getblk_failed;
2080                         if (ea_inode) {
2081                                 /* Drop the extra ref on ea_inode. */
2082                                 error = ext4_xattr_inode_dec_ref(handle,
2083                                                                  ea_inode);
2084                                 if (error)
2085                                         ext4_warning_inode(ea_inode,
2086                                                            "dec ref error=%d",
2087                                                            error);
2088                                 iput(ea_inode);
2089                                 ea_inode = NULL;
2090                         }
2091
2092                         lock_buffer(new_bh);
2093                         error = ext4_journal_get_create_access(handle, new_bh);
2094                         if (error) {
2095                                 unlock_buffer(new_bh);
2096                                 error = -EIO;
2097                                 goto getblk_failed;
2098                         }
2099                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2100                         ext4_xattr_block_csum_set(inode, new_bh);
2101                         set_buffer_uptodate(new_bh);
2102                         unlock_buffer(new_bh);
2103                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2104                         error = ext4_handle_dirty_metadata(handle, inode,
2105                                                            new_bh);
2106                         if (error)
2107                                 goto cleanup;
2108                 }
2109         }
2110
2111         if (old_ea_inode_quota)
2112                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2113
2114         /* Update the inode. */
2115         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2116
2117         /* Drop the previous xattr block. */
2118         if (bs->bh && bs->bh != new_bh) {
2119                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2120
2121                 ext4_xattr_release_block(handle, inode, bs->bh,
2122                                          &ea_inode_array,
2123                                          0 /* extra_credits */);
2124                 ext4_xattr_inode_array_free(ea_inode_array);
2125         }
2126         error = 0;
2127
2128 cleanup:
2129         if (ea_inode) {
2130                 int error2;
2131
2132                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2133                 if (error2)
2134                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2135                                            error2);
2136
2137                 /* If there was an error, revert the quota charge. */
2138                 if (error)
2139                         ext4_xattr_inode_free_quota(inode, ea_inode,
2140                                                     i_size_read(ea_inode));
2141                 iput(ea_inode);
2142         }
2143         if (ce)
2144                 mb_cache_entry_put(ea_block_cache, ce);
2145         brelse(new_bh);
2146         if (!(bs->bh && s->base == bs->bh->b_data))
2147                 kfree(s->base);
2148
2149         return error;
2150
2151 cleanup_dquot:
2152         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2153         goto cleanup;
2154
2155 bad_block:
2156         EXT4_ERROR_INODE(inode, "bad block %llu",
2157                          EXT4_I(inode)->i_file_acl);
2158         goto cleanup;
2159
2160 #undef header
2161 }
2162
2163 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2164                           struct ext4_xattr_ibody_find *is)
2165 {
2166         struct ext4_xattr_ibody_header *header;
2167         struct ext4_inode *raw_inode;
2168         int error;
2169
2170         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2171                 return 0;
2172
2173         raw_inode = ext4_raw_inode(&is->iloc);
2174         header = IHDR(inode, raw_inode);
2175         is->s.base = is->s.first = IFIRST(header);
2176         is->s.here = is->s.first;
2177         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2178         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2179                 error = xattr_check_inode(inode, header, is->s.end);
2180                 if (error)
2181                         return error;
2182                 /* Find the named attribute. */
2183                 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2184                                          i->name_index, i->name, 0);
2185                 if (error && error != -ENODATA)
2186                         return error;
2187                 is->s.not_found = error;
2188         }
2189         return 0;
2190 }
2191
2192 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2193                                 struct ext4_xattr_info *i,
2194                                 struct ext4_xattr_ibody_find *is)
2195 {
2196         struct ext4_xattr_ibody_header *header;
2197         struct ext4_xattr_search *s = &is->s;
2198         int error;
2199
2200         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2201                 return -ENOSPC;
2202
2203         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2204         if (error)
2205                 return error;
2206         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2207         if (!IS_LAST_ENTRY(s->first)) {
2208                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2209                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2210         } else {
2211                 header->h_magic = cpu_to_le32(0);
2212                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2213         }
2214         return 0;
2215 }
2216
2217 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2218                                 struct ext4_xattr_info *i,
2219                                 struct ext4_xattr_ibody_find *is)
2220 {
2221         struct ext4_xattr_ibody_header *header;
2222         struct ext4_xattr_search *s = &is->s;
2223         int error;
2224
2225         if (EXT4_I(inode)->i_extra_isize == 0)
2226                 return -ENOSPC;
2227         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2228         if (error)
2229                 return error;
2230         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2231         if (!IS_LAST_ENTRY(s->first)) {
2232                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2233                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2234         } else {
2235                 header->h_magic = cpu_to_le32(0);
2236                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2237         }
2238         return 0;
2239 }
2240
2241 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2242                                  struct ext4_xattr_info *i)
2243 {
2244         void *value;
2245
2246         /* When e_value_inum is set the value is stored externally. */
2247         if (s->here->e_value_inum)
2248                 return 0;
2249         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2250                 return 0;
2251         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2252         return !memcmp(value, i->value, i->value_len);
2253 }
2254
2255 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2256 {
2257         struct buffer_head *bh;
2258         int error;
2259
2260         if (!EXT4_I(inode)->i_file_acl)
2261                 return NULL;
2262         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2263         if (IS_ERR(bh))
2264                 return bh;
2265         error = ext4_xattr_check_block(inode, bh);
2266         if (error) {
2267                 brelse(bh);
2268                 return ERR_PTR(error);
2269         }
2270         return bh;
2271 }
2272
2273 /*
2274  * ext4_xattr_set_handle()
2275  *
2276  * Create, replace or remove an extended attribute for this inode.  Value
2277  * is NULL to remove an existing extended attribute, and non-NULL to
2278  * either replace an existing extended attribute, or create a new extended
2279  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2280  * specify that an extended attribute must exist and must not exist
2281  * previous to the call, respectively.
2282  *
2283  * Returns 0, or a negative error number on failure.
2284  */
2285 int
2286 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2287                       const char *name, const void *value, size_t value_len,
2288                       int flags)
2289 {
2290         struct ext4_xattr_info i = {
2291                 .name_index = name_index,
2292                 .name = name,
2293                 .value = value,
2294                 .value_len = value_len,
2295                 .in_inode = 0,
2296         };
2297         struct ext4_xattr_ibody_find is = {
2298                 .s = { .not_found = -ENODATA, },
2299         };
2300         struct ext4_xattr_block_find bs = {
2301                 .s = { .not_found = -ENODATA, },
2302         };
2303         int no_expand;
2304         int error;
2305
2306         if (!name)
2307                 return -EINVAL;
2308         if (strlen(name) > 255)
2309                 return -ERANGE;
2310
2311         ext4_write_lock_xattr(inode, &no_expand);
2312
2313         /* Check journal credits under write lock. */
2314         if (ext4_handle_valid(handle)) {
2315                 struct buffer_head *bh;
2316                 int credits;
2317
2318                 bh = ext4_xattr_get_block(inode);
2319                 if (IS_ERR(bh)) {
2320                         error = PTR_ERR(bh);
2321                         goto cleanup;
2322                 }
2323
2324                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2325                                                    value_len,
2326                                                    flags & XATTR_CREATE);
2327                 brelse(bh);
2328
2329                 if (jbd2_handle_buffer_credits(handle) < credits) {
2330                         error = -ENOSPC;
2331                         goto cleanup;
2332                 }
2333                 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2334         }
2335
2336         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2337         if (error)
2338                 goto cleanup;
2339
2340         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2341                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2342                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2343                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2344         }
2345
2346         error = ext4_xattr_ibody_find(inode, &i, &is);
2347         if (error)
2348                 goto cleanup;
2349         if (is.s.not_found)
2350                 error = ext4_xattr_block_find(inode, &i, &bs);
2351         if (error)
2352                 goto cleanup;
2353         if (is.s.not_found && bs.s.not_found) {
2354                 error = -ENODATA;
2355                 if (flags & XATTR_REPLACE)
2356                         goto cleanup;
2357                 error = 0;
2358                 if (!value)
2359                         goto cleanup;
2360         } else {
2361                 error = -EEXIST;
2362                 if (flags & XATTR_CREATE)
2363                         goto cleanup;
2364         }
2365
2366         if (!value) {
2367                 if (!is.s.not_found)
2368                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2369                 else if (!bs.s.not_found)
2370                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2371         } else {
2372                 error = 0;
2373                 /* Xattr value did not change? Save us some work and bail out */
2374                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2375                         goto cleanup;
2376                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2377                         goto cleanup;
2378
2379                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2380                     (EXT4_XATTR_SIZE(i.value_len) >
2381                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2382                         i.in_inode = 1;
2383 retry_inode:
2384                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2385                 if (!error && !bs.s.not_found) {
2386                         i.value = NULL;
2387                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2388                 } else if (error == -ENOSPC) {
2389                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2390                                 brelse(bs.bh);
2391                                 bs.bh = NULL;
2392                                 error = ext4_xattr_block_find(inode, &i, &bs);
2393                                 if (error)
2394                                         goto cleanup;
2395                         }
2396                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2397                         if (!error && !is.s.not_found) {
2398                                 i.value = NULL;
2399                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2400                                                              &is);
2401                         } else if (error == -ENOSPC) {
2402                                 /*
2403                                  * Xattr does not fit in the block, store at
2404                                  * external inode if possible.
2405                                  */
2406                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2407                                     i.value_len && !i.in_inode) {
2408                                         i.in_inode = 1;
2409                                         goto retry_inode;
2410                                 }
2411                         }
2412                 }
2413         }
2414         if (!error) {
2415                 ext4_xattr_update_super_block(handle, inode->i_sb);
2416                 inode->i_ctime = current_time(inode);
2417                 if (!value)
2418                         no_expand = 0;
2419                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2420                 /*
2421                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2422                  * error != 0.
2423                  */
2424                 is.iloc.bh = NULL;
2425                 if (IS_SYNC(inode))
2426                         ext4_handle_sync(handle);
2427         }
2428         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2429
2430 cleanup:
2431         brelse(is.iloc.bh);
2432         brelse(bs.bh);
2433         ext4_write_unlock_xattr(inode, &no_expand);
2434         return error;
2435 }
2436
2437 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2438                            bool is_create, int *credits)
2439 {
2440         struct buffer_head *bh;
2441         int err;
2442
2443         *credits = 0;
2444
2445         if (!EXT4_SB(inode->i_sb)->s_journal)
2446                 return 0;
2447
2448         down_read(&EXT4_I(inode)->xattr_sem);
2449
2450         bh = ext4_xattr_get_block(inode);
2451         if (IS_ERR(bh)) {
2452                 err = PTR_ERR(bh);
2453         } else {
2454                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2455                                                     value_len, is_create);
2456                 brelse(bh);
2457                 err = 0;
2458         }
2459
2460         up_read(&EXT4_I(inode)->xattr_sem);
2461         return err;
2462 }
2463
2464 /*
2465  * ext4_xattr_set()
2466  *
2467  * Like ext4_xattr_set_handle, but start from an inode. This extended
2468  * attribute modification is a filesystem transaction by itself.
2469  *
2470  * Returns 0, or a negative error number on failure.
2471  */
2472 int
2473 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2474                const void *value, size_t value_len, int flags)
2475 {
2476         handle_t *handle;
2477         struct super_block *sb = inode->i_sb;
2478         int error, retries = 0;
2479         int credits;
2480
2481         error = dquot_initialize(inode);
2482         if (error)
2483                 return error;
2484
2485 retry:
2486         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2487                                        &credits);
2488         if (error)
2489                 return error;
2490
2491         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2492         if (IS_ERR(handle)) {
2493                 error = PTR_ERR(handle);
2494         } else {
2495                 int error2;
2496
2497                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2498                                               value, value_len, flags);
2499                 error2 = ext4_journal_stop(handle);
2500                 if (error == -ENOSPC &&
2501                     ext4_should_retry_alloc(sb, &retries))
2502                         goto retry;
2503                 if (error == 0)
2504                         error = error2;
2505         }
2506         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2507
2508         return error;
2509 }
2510
2511 /*
2512  * Shift the EA entries in the inode to create space for the increased
2513  * i_extra_isize.
2514  */
2515 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2516                                      int value_offs_shift, void *to,
2517                                      void *from, size_t n)
2518 {
2519         struct ext4_xattr_entry *last = entry;
2520         int new_offs;
2521
2522         /* We always shift xattr headers further thus offsets get lower */
2523         BUG_ON(value_offs_shift > 0);
2524
2525         /* Adjust the value offsets of the entries */
2526         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2527                 if (!last->e_value_inum && last->e_value_size) {
2528                         new_offs = le16_to_cpu(last->e_value_offs) +
2529                                                         value_offs_shift;
2530                         last->e_value_offs = cpu_to_le16(new_offs);
2531                 }
2532         }
2533         /* Shift the entries by n bytes */
2534         memmove(to, from, n);
2535 }
2536
2537 /*
2538  * Move xattr pointed to by 'entry' from inode into external xattr block
2539  */
2540 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2541                                     struct ext4_inode *raw_inode,
2542                                     struct ext4_xattr_entry *entry)
2543 {
2544         struct ext4_xattr_ibody_find *is = NULL;
2545         struct ext4_xattr_block_find *bs = NULL;
2546         char *buffer = NULL, *b_entry_name = NULL;
2547         size_t value_size = le32_to_cpu(entry->e_value_size);
2548         struct ext4_xattr_info i = {
2549                 .value = NULL,
2550                 .value_len = 0,
2551                 .name_index = entry->e_name_index,
2552                 .in_inode = !!entry->e_value_inum,
2553         };
2554         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2555         int error;
2556
2557         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2558         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2559         buffer = kmalloc(value_size, GFP_NOFS);
2560         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2561         if (!is || !bs || !buffer || !b_entry_name) {
2562                 error = -ENOMEM;
2563                 goto out;
2564         }
2565
2566         is->s.not_found = -ENODATA;
2567         bs->s.not_found = -ENODATA;
2568         is->iloc.bh = NULL;
2569         bs->bh = NULL;
2570
2571         /* Save the entry name and the entry value */
2572         if (entry->e_value_inum) {
2573                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2574                 if (error)
2575                         goto out;
2576         } else {
2577                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2578                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2579         }
2580
2581         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2582         b_entry_name[entry->e_name_len] = '\0';
2583         i.name = b_entry_name;
2584
2585         error = ext4_get_inode_loc(inode, &is->iloc);
2586         if (error)
2587                 goto out;
2588
2589         error = ext4_xattr_ibody_find(inode, &i, is);
2590         if (error)
2591                 goto out;
2592
2593         /* Remove the chosen entry from the inode */
2594         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2595         if (error)
2596                 goto out;
2597
2598         i.value = buffer;
2599         i.value_len = value_size;
2600         error = ext4_xattr_block_find(inode, &i, bs);
2601         if (error)
2602                 goto out;
2603
2604         /* Add entry which was removed from the inode into the block */
2605         error = ext4_xattr_block_set(handle, inode, &i, bs);
2606         if (error)
2607                 goto out;
2608         error = 0;
2609 out:
2610         kfree(b_entry_name);
2611         kfree(buffer);
2612         if (is)
2613                 brelse(is->iloc.bh);
2614         if (bs)
2615                 brelse(bs->bh);
2616         kfree(is);
2617         kfree(bs);
2618
2619         return error;
2620 }
2621
2622 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2623                                        struct ext4_inode *raw_inode,
2624                                        int isize_diff, size_t ifree,
2625                                        size_t bfree, int *total_ino)
2626 {
2627         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2628         struct ext4_xattr_entry *small_entry;
2629         struct ext4_xattr_entry *entry;
2630         struct ext4_xattr_entry *last;
2631         unsigned int entry_size;        /* EA entry size */
2632         unsigned int total_size;        /* EA entry size + value size */
2633         unsigned int min_total_size;
2634         int error;
2635
2636         while (isize_diff > ifree) {
2637                 entry = NULL;
2638                 small_entry = NULL;
2639                 min_total_size = ~0U;
2640                 last = IFIRST(header);
2641                 /* Find the entry best suited to be pushed into EA block */
2642                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2643                         /* never move system.data out of the inode */
2644                         if ((last->e_name_len == 4) &&
2645                             (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2646                             !memcmp(last->e_name, "data", 4))
2647                                 continue;
2648                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2649                         if (!last->e_value_inum)
2650                                 total_size += EXT4_XATTR_SIZE(
2651                                                le32_to_cpu(last->e_value_size));
2652                         if (total_size <= bfree &&
2653                             total_size < min_total_size) {
2654                                 if (total_size + ifree < isize_diff) {
2655                                         small_entry = last;
2656                                 } else {
2657                                         entry = last;
2658                                         min_total_size = total_size;
2659                                 }
2660                         }
2661                 }
2662
2663                 if (entry == NULL) {
2664                         if (small_entry == NULL)
2665                                 return -ENOSPC;
2666                         entry = small_entry;
2667                 }
2668
2669                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2670                 total_size = entry_size;
2671                 if (!entry->e_value_inum)
2672                         total_size += EXT4_XATTR_SIZE(
2673                                               le32_to_cpu(entry->e_value_size));
2674                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2675                                                  entry);
2676                 if (error)
2677                         return error;
2678
2679                 *total_ino -= entry_size;
2680                 ifree += total_size;
2681                 bfree -= total_size;
2682         }
2683
2684         return 0;
2685 }
2686
2687 /*
2688  * Expand an inode by new_extra_isize bytes when EAs are present.
2689  * Returns 0 on success or negative error number on failure.
2690  */
2691 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2692                                struct ext4_inode *raw_inode, handle_t *handle)
2693 {
2694         struct ext4_xattr_ibody_header *header;
2695         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2696         static unsigned int mnt_count;
2697         size_t min_offs;
2698         size_t ifree, bfree;
2699         int total_ino;
2700         void *base, *end;
2701         int error = 0, tried_min_extra_isize = 0;
2702         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2703         int isize_diff; /* How much do we need to grow i_extra_isize */
2704
2705 retry:
2706         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2707         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2708                 return 0;
2709
2710         header = IHDR(inode, raw_inode);
2711
2712         /*
2713          * Check if enough free space is available in the inode to shift the
2714          * entries ahead by new_extra_isize.
2715          */
2716
2717         base = IFIRST(header);
2718         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2719         min_offs = end - base;
2720         total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2721
2722         error = xattr_check_inode(inode, header, end);
2723         if (error)
2724                 goto cleanup;
2725
2726         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2727         if (ifree >= isize_diff)
2728                 goto shift;
2729
2730         /*
2731          * Enough free space isn't available in the inode, check if
2732          * EA block can hold new_extra_isize bytes.
2733          */
2734         if (EXT4_I(inode)->i_file_acl) {
2735                 struct buffer_head *bh;
2736
2737                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2738                 if (IS_ERR(bh)) {
2739                         error = PTR_ERR(bh);
2740                         goto cleanup;
2741                 }
2742                 error = ext4_xattr_check_block(inode, bh);
2743                 if (error) {
2744                         brelse(bh);
2745                         goto cleanup;
2746                 }
2747                 base = BHDR(bh);
2748                 end = bh->b_data + bh->b_size;
2749                 min_offs = end - base;
2750                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2751                                               NULL);
2752                 brelse(bh);
2753                 if (bfree + ifree < isize_diff) {
2754                         if (!tried_min_extra_isize && s_min_extra_isize) {
2755                                 tried_min_extra_isize++;
2756                                 new_extra_isize = s_min_extra_isize;
2757                                 goto retry;
2758                         }
2759                         error = -ENOSPC;
2760                         goto cleanup;
2761                 }
2762         } else {
2763                 bfree = inode->i_sb->s_blocksize;
2764         }
2765
2766         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2767                                             isize_diff, ifree, bfree,
2768                                             &total_ino);
2769         if (error) {
2770                 if (error == -ENOSPC && !tried_min_extra_isize &&
2771                     s_min_extra_isize) {
2772                         tried_min_extra_isize++;
2773                         new_extra_isize = s_min_extra_isize;
2774                         goto retry;
2775                 }
2776                 goto cleanup;
2777         }
2778 shift:
2779         /* Adjust the offsets and shift the remaining entries ahead */
2780         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2781                         - new_extra_isize, (void *)raw_inode +
2782                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2783                         (void *)header, total_ino);
2784         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2785
2786 cleanup:
2787         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2788                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2789                              inode->i_ino);
2790                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2791         }
2792         return error;
2793 }
2794
2795 #define EIA_INCR 16 /* must be 2^n */
2796 #define EIA_MASK (EIA_INCR - 1)
2797
2798 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2799  * If @ea_inode_array is new or full it will be grown and the old
2800  * contents copied over.
2801  */
2802 static int
2803 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2804                         struct inode *inode)
2805 {
2806         if (*ea_inode_array == NULL) {
2807                 /*
2808                  * Start with 15 inodes, so it fits into a power-of-two size.
2809                  * If *ea_inode_array is NULL, this is essentially offsetof()
2810                  */
2811                 (*ea_inode_array) =
2812                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2813                                          inodes[EIA_MASK]),
2814                                 GFP_NOFS);
2815                 if (*ea_inode_array == NULL)
2816                         return -ENOMEM;
2817                 (*ea_inode_array)->count = 0;
2818         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2819                 /* expand the array once all 15 + n * 16 slots are full */
2820                 struct ext4_xattr_inode_array *new_array = NULL;
2821                 int count = (*ea_inode_array)->count;
2822
2823                 /* if new_array is NULL, this is essentially offsetof() */
2824                 new_array = kmalloc(
2825                                 offsetof(struct ext4_xattr_inode_array,
2826                                          inodes[count + EIA_INCR]),
2827                                 GFP_NOFS);
2828                 if (new_array == NULL)
2829                         return -ENOMEM;
2830                 memcpy(new_array, *ea_inode_array,
2831                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2832                 kfree(*ea_inode_array);
2833                 *ea_inode_array = new_array;
2834         }
2835         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2836         return 0;
2837 }
2838
2839 /*
2840  * ext4_xattr_delete_inode()
2841  *
2842  * Free extended attribute resources associated with this inode. Traverse
2843  * all entries and decrement reference on any xattr inodes associated with this
2844  * inode. This is called immediately before an inode is freed. We have exclusive
2845  * access to the inode. If an orphan inode is deleted it will also release its
2846  * references on xattr block and xattr inodes.
2847  */
2848 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2849                             struct ext4_xattr_inode_array **ea_inode_array,
2850                             int extra_credits)
2851 {
2852         struct buffer_head *bh = NULL;
2853         struct ext4_xattr_ibody_header *header;
2854         struct ext4_iloc iloc = { .bh = NULL };
2855         struct ext4_xattr_entry *entry;
2856         struct inode *ea_inode;
2857         int error;
2858
2859         error = ext4_journal_ensure_credits(handle, extra_credits,
2860                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2861         if (error < 0) {
2862                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2863                 goto cleanup;
2864         }
2865
2866         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2867             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2868
2869                 error = ext4_get_inode_loc(inode, &iloc);
2870                 if (error) {
2871                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2872                         goto cleanup;
2873                 }
2874
2875                 error = ext4_journal_get_write_access(handle, iloc.bh);
2876                 if (error) {
2877                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2878                                          error);
2879                         goto cleanup;
2880                 }
2881
2882                 header = IHDR(inode, ext4_raw_inode(&iloc));
2883                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2884                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2885                                                      IFIRST(header),
2886                                                      false /* block_csum */,
2887                                                      ea_inode_array,
2888                                                      extra_credits,
2889                                                      false /* skip_quota */);
2890         }
2891
2892         if (EXT4_I(inode)->i_file_acl) {
2893                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2894                 if (IS_ERR(bh)) {
2895                         error = PTR_ERR(bh);
2896                         if (error == -EIO) {
2897                                 EXT4_ERROR_INODE_ERR(inode, EIO,
2898                                                      "block %llu read error",
2899                                                      EXT4_I(inode)->i_file_acl);
2900                         }
2901                         bh = NULL;
2902                         goto cleanup;
2903                 }
2904                 error = ext4_xattr_check_block(inode, bh);
2905                 if (error)
2906                         goto cleanup;
2907
2908                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2909                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2910                              entry = EXT4_XATTR_NEXT(entry)) {
2911                                 if (!entry->e_value_inum)
2912                                         continue;
2913                                 error = ext4_xattr_inode_iget(inode,
2914                                               le32_to_cpu(entry->e_value_inum),
2915                                               le32_to_cpu(entry->e_hash),
2916                                               &ea_inode);
2917                                 if (error)
2918                                         continue;
2919                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2920                                               le32_to_cpu(entry->e_value_size));
2921                                 iput(ea_inode);
2922                         }
2923
2924                 }
2925
2926                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2927                                          extra_credits);
2928                 /*
2929                  * Update i_file_acl value in the same transaction that releases
2930                  * block.
2931                  */
2932                 EXT4_I(inode)->i_file_acl = 0;
2933                 error = ext4_mark_inode_dirty(handle, inode);
2934                 if (error) {
2935                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2936                                          error);
2937                         goto cleanup;
2938                 }
2939                 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2940         }
2941         error = 0;
2942 cleanup:
2943         brelse(iloc.bh);
2944         brelse(bh);
2945         return error;
2946 }
2947
2948 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2949 {
2950         int idx;
2951
2952         if (ea_inode_array == NULL)
2953                 return;
2954
2955         for (idx = 0; idx < ea_inode_array->count; ++idx)
2956                 iput(ea_inode_array->inodes[idx]);
2957         kfree(ea_inode_array);
2958 }
2959
2960 /*
2961  * ext4_xattr_block_cache_insert()
2962  *
2963  * Create a new entry in the extended attribute block cache, and insert
2964  * it unless such an entry is already in the cache.
2965  *
2966  * Returns 0, or a negative error number on failure.
2967  */
2968 static void
2969 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2970                               struct buffer_head *bh)
2971 {
2972         struct ext4_xattr_header *header = BHDR(bh);
2973         __u32 hash = le32_to_cpu(header->h_hash);
2974         int reusable = le32_to_cpu(header->h_refcount) <
2975                        EXT4_XATTR_REFCOUNT_MAX;
2976         int error;
2977
2978         if (!ea_block_cache)
2979                 return;
2980         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2981                                       bh->b_blocknr, reusable);
2982         if (error) {
2983                 if (error == -EBUSY)
2984                         ea_bdebug(bh, "already in cache");
2985         } else
2986                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2987 }
2988
2989 /*
2990  * ext4_xattr_cmp()
2991  *
2992  * Compare two extended attribute blocks for equality.
2993  *
2994  * Returns 0 if the blocks are equal, 1 if they differ, and
2995  * a negative error number on errors.
2996  */
2997 static int
2998 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2999                struct ext4_xattr_header *header2)
3000 {
3001         struct ext4_xattr_entry *entry1, *entry2;
3002
3003         entry1 = ENTRY(header1+1);
3004         entry2 = ENTRY(header2+1);
3005         while (!IS_LAST_ENTRY(entry1)) {
3006                 if (IS_LAST_ENTRY(entry2))
3007                         return 1;
3008                 if (entry1->e_hash != entry2->e_hash ||
3009                     entry1->e_name_index != entry2->e_name_index ||
3010                     entry1->e_name_len != entry2->e_name_len ||
3011                     entry1->e_value_size != entry2->e_value_size ||
3012                     entry1->e_value_inum != entry2->e_value_inum ||
3013                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3014                         return 1;
3015                 if (!entry1->e_value_inum &&
3016                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3017                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3018                            le32_to_cpu(entry1->e_value_size)))
3019                         return 1;
3020
3021                 entry1 = EXT4_XATTR_NEXT(entry1);
3022                 entry2 = EXT4_XATTR_NEXT(entry2);
3023         }
3024         if (!IS_LAST_ENTRY(entry2))
3025                 return 1;
3026         return 0;
3027 }
3028
3029 /*
3030  * ext4_xattr_block_cache_find()
3031  *
3032  * Find an identical extended attribute block.
3033  *
3034  * Returns a pointer to the block found, or NULL if such a block was
3035  * not found or an error occurred.
3036  */
3037 static struct buffer_head *
3038 ext4_xattr_block_cache_find(struct inode *inode,
3039                             struct ext4_xattr_header *header,
3040                             struct mb_cache_entry **pce)
3041 {
3042         __u32 hash = le32_to_cpu(header->h_hash);
3043         struct mb_cache_entry *ce;
3044         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3045
3046         if (!ea_block_cache)
3047                 return NULL;
3048         if (!header->h_hash)
3049                 return NULL;  /* never share */
3050         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3051         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3052         while (ce) {
3053                 struct buffer_head *bh;
3054
3055                 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3056                 if (IS_ERR(bh)) {
3057                         if (PTR_ERR(bh) == -ENOMEM)
3058                                 return NULL;
3059                         bh = NULL;
3060                         EXT4_ERROR_INODE(inode, "block %lu read error",
3061                                          (unsigned long)ce->e_value);
3062                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3063                         *pce = ce;
3064                         return bh;
3065                 }
3066                 brelse(bh);
3067                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3068         }
3069         return NULL;
3070 }
3071
3072 #define NAME_HASH_SHIFT 5
3073 #define VALUE_HASH_SHIFT 16
3074
3075 /*
3076  * ext4_xattr_hash_entry()
3077  *
3078  * Compute the hash of an extended attribute.
3079  */
3080 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3081                                     size_t value_count)
3082 {
3083         __u32 hash = 0;
3084
3085         while (name_len--) {
3086                 hash = (hash << NAME_HASH_SHIFT) ^
3087                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3088                        *name++;
3089         }
3090         while (value_count--) {
3091                 hash = (hash << VALUE_HASH_SHIFT) ^
3092                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3093                        le32_to_cpu(*value++);
3094         }
3095         return cpu_to_le32(hash);
3096 }
3097
3098 #undef NAME_HASH_SHIFT
3099 #undef VALUE_HASH_SHIFT
3100
3101 #define BLOCK_HASH_SHIFT 16
3102
3103 /*
3104  * ext4_xattr_rehash()
3105  *
3106  * Re-compute the extended attribute hash value after an entry has changed.
3107  */
3108 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3109 {
3110         struct ext4_xattr_entry *here;
3111         __u32 hash = 0;
3112
3113         here = ENTRY(header+1);
3114         while (!IS_LAST_ENTRY(here)) {
3115                 if (!here->e_hash) {
3116                         /* Block is not shared if an entry's hash value == 0 */
3117                         hash = 0;
3118                         break;
3119                 }
3120                 hash = (hash << BLOCK_HASH_SHIFT) ^
3121                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3122                        le32_to_cpu(here->e_hash);
3123                 here = EXT4_XATTR_NEXT(here);
3124         }
3125         header->h_hash = cpu_to_le32(hash);
3126 }
3127
3128 #undef BLOCK_HASH_SHIFT
3129
3130 #define HASH_BUCKET_BITS        10
3131
3132 struct mb_cache *
3133 ext4_xattr_create_cache(void)
3134 {
3135         return mb_cache_create(HASH_BUCKET_BITS);
3136 }
3137
3138 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3139 {
3140         if (cache)
3141                 mb_cache_destroy(cache);
3142 }
3143