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         struct ext4_inode_info *ei = EXT4_I(ea_inode);
 127
 128         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 129         (void) ei;      /* shut up clang warning if !CONFIG_LOCKDEP */
 130         lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
 131 }
 132 #endif
 133
 134 static __le32 ext4_xattr_block_csum(struct inode *inode,
 135                                     sector_t block_nr,
 136                                     struct ext4_xattr_header *hdr)
 137 {
 138         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 139         __u32 csum;
 140         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 141         __u32 dummy_csum = 0;
 142         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 143
 144         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 145                            sizeof(dsk_block_nr));
 146         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 147         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 148         offset += sizeof(dummy_csum);
 149         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 150                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 151
 152         return cpu_to_le32(csum);
 153 }
 154
 155 static int ext4_xattr_block_csum_verify(struct inode *inode,
 156                                         struct buffer_head *bh)
 157 {
 158         struct ext4_xattr_header *hdr = BHDR(bh);
 159         int ret = 1;
 160
 161         if (ext4_has_metadata_csum(inode->i_sb)) {
 162                 lock_buffer(bh);
 163                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 164                                                         bh->b_blocknr, hdr));
 165                 unlock_buffer(bh);
 166         }
 167         return ret;
 168 }
 169
 170 static void ext4_xattr_block_csum_set(struct inode *inode,
 171                                       struct buffer_head *bh)
 172 {
 173         if (ext4_has_metadata_csum(inode->i_sb))
 174                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 175                                                 bh->b_blocknr, BHDR(bh));
 176 }
 177
 178 static inline const struct xattr_handler *
 179 ext4_xattr_handler(int name_index)
 180 {
 181         const struct xattr_handler *handler = NULL;
 182
 183         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 184                 handler = ext4_xattr_handler_map[name_index];
 185         return handler;
 186 }
 187
 188 static int
 189 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
 190                          void *value_start)
 191 {
 192         struct ext4_xattr_entry *e = entry;
 193
 194         /* Find the end of the names list */
 195         while (!IS_LAST_ENTRY(e)) {
 196                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 197                 if ((void *)next >= end)
 198                         return -EFSCORRUPTED;
 199                 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
 200                         return -EFSCORRUPTED;
 201                 e = next;
 202         }
 203
 204         /* Check the values */
 205         while (!IS_LAST_ENTRY(entry)) {
 206                 u32 size = le32_to_cpu(entry->e_value_size);
 207
 208                 if (size > EXT4_XATTR_SIZE_MAX)
 209                         return -EFSCORRUPTED;
 210
 211                 if (size != 0 && entry->e_value_inum == 0) {
 212                         u16 offs = le16_to_cpu(entry->e_value_offs);
 213                         void *value;
 214
 215                         /*
 216                          * The value cannot overlap the names, and the value
 217                          * with padding cannot extend beyond 'end'.  Check both
 218                          * the padded and unpadded sizes, since the size may
 219                          * overflow to 0 when adding padding.
 220                          */
 221                         if (offs > end - value_start)
 222                                 return -EFSCORRUPTED;
 223                         value = value_start + offs;
 224                         if (value < (void *)e + sizeof(u32) ||
 225                             size > end - value ||
 226                             EXT4_XATTR_SIZE(size) > end - value)
 227                                 return -EFSCORRUPTED;
 228                 }
 229                 entry = EXT4_XATTR_NEXT(entry);
 230         }
 231
 232         return 0;
 233 }
 234
 235 static inline int
 236 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
 237                          const char *function, unsigned int line)
 238 {
 239         int error = -EFSCORRUPTED;
 240
 241         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 242             BHDR(bh)->h_blocks != cpu_to_le32(1))
 243                 goto errout;
 244         if (buffer_verified(bh))
 245                 return 0;
 246
 247         error = -EFSBADCRC;
 248         if (!ext4_xattr_block_csum_verify(inode, bh))
 249                 goto errout;
 250         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 251                                          bh->b_data);
 252 errout:
 253         if (error)
 254                 __ext4_error_inode(inode, function, line, 0, -error,
 255                                    "corrupted xattr block %llu",
 256                                    (unsigned long long) bh->b_blocknr);
 257         else
 258                 set_buffer_verified(bh);
 259         return error;
 260 }
 261
 262 #define ext4_xattr_check_block(inode, bh) \
 263         __ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
 264
 265
 266 static int
 267 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 268                          void *end, const char *function, unsigned int line)
 269 {
 270         int error = -EFSCORRUPTED;
 271
 272         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 273             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 274                 goto errout;
 275         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 276 errout:
 277         if (error)
 278                 __ext4_error_inode(inode, function, line, 0, -error,
 279                                    "corrupted in-inode xattr");
 280         return error;
 281 }
 282
 283 #define xattr_check_inode(inode, header, end) \
 284         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 285
 286 static int
 287 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
 288                  void *end, int name_index, const char *name, int sorted)
 289 {
 290         struct ext4_xattr_entry *entry, *next;
 291         size_t name_len;
 292         int cmp = 1;
 293
 294         if (name == NULL)
 295                 return -EINVAL;
 296         name_len = strlen(name);
 297         for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
 298                 next = EXT4_XATTR_NEXT(entry);
 299                 if ((void *) next >= end) {
 300                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
 301                         return -EFSCORRUPTED;
 302                 }
 303                 cmp = name_index - entry->e_name_index;
 304                 if (!cmp)
 305                         cmp = name_len - entry->e_name_len;
 306                 if (!cmp)
 307                         cmp = memcmp(name, entry->e_name, name_len);
 308                 if (cmp <= 0 && (sorted || cmp == 0))
 309                         break;
 310         }
 311         *pentry = entry;
 312         return cmp ? -ENODATA : 0;
 313 }
 314
 315 static u32
 316 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 317 {
 318         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 319 }
 320
 321 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 322 {
 323         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 324                 (u32) inode_peek_iversion_raw(ea_inode);
 325 }
 326
 327 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 328 {
 329         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 330         inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
 331 }
 332
 333 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 334 {
 335         return (u32)ea_inode->i_atime.tv_sec;
 336 }
 337
 338 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 339 {
 340         ea_inode->i_atime.tv_sec = hash;
 341 }
 342
 343 /*
 344  * Read the EA value from an inode.
 345  */
 346 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 347 {
 348         int blocksize = 1 << ea_inode->i_blkbits;
 349         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 350         int tail_size = (size % blocksize) ?: blocksize;
 351         struct buffer_head *bhs_inline[8];
 352         struct buffer_head **bhs = bhs_inline;
 353         int i, ret;
 354
 355         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 356                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 357                 if (!bhs)
 358                         return -ENOMEM;
 359         }
 360
 361         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 362                                true /* wait */, bhs);
 363         if (ret)
 364                 goto free_bhs;
 365
 366         for (i = 0; i < bh_count; i++) {
 367                 /* There shouldn't be any holes in ea_inode. */
 368                 if (!bhs[i]) {
 369                         ret = -EFSCORRUPTED;
 370                         goto put_bhs;
 371                 }
 372                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 373                        i < bh_count - 1 ? blocksize : tail_size);
 374         }
 375         ret = 0;
 376 put_bhs:
 377         for (i = 0; i < bh_count; i++)
 378                 brelse(bhs[i]);
 379 free_bhs:
 380         if (bhs != bhs_inline)
 381                 kfree(bhs);
 382         return ret;
 383 }
 384
 385 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 386
 387 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 388                                  u32 ea_inode_hash, struct inode **ea_inode)
 389 {
 390         struct inode *inode;
 391         int err;
 392
 393         /*
 394          * We have to check for this corruption early as otherwise
 395          * iget_locked() could wait indefinitely for the state of our
 396          * parent inode.
 397          */
 398         if (parent->i_ino == ea_ino) {
 399                 ext4_error(parent->i_sb,
 400                            "Parent and EA inode have the same ino %lu", ea_ino);
 401                 return -EFSCORRUPTED;
 402         }
 403
 404         inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
 405         if (IS_ERR(inode)) {
 406                 err = PTR_ERR(inode);
 407                 ext4_error(parent->i_sb,
 408                            "error while reading EA inode %lu err=%d", ea_ino,
 409                            err);
 410                 return err;
 411         }
 412         ext4_xattr_inode_set_class(inode);
 413
 414         /*
 415          * Check whether this is an old Lustre-style xattr inode. Lustre
 416          * implementation does not have hash validation, rather it has a
 417          * backpointer from ea_inode to the parent inode.
 418          */
 419         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 420             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 421             inode->i_generation == parent->i_generation) {
 422                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 423                 ext4_xattr_inode_set_ref(inode, 1);
 424         } else {
 425                 inode_lock(inode);
 426                 inode->i_flags |= S_NOQUOTA;
 427                 inode_unlock(inode);
 428         }
 429
 430         *ea_inode = inode;
 431         return 0;
 432 }
 433
 434 /* Remove entry from mbcache when EA inode is getting evicted */
 435 void ext4_evict_ea_inode(struct inode *inode)
 436 {
 437         struct mb_cache_entry *oe;
 438
 439         if (!EA_INODE_CACHE(inode))
 440                 return;
 441         /* Wait for entry to get unused so that we can remove it */
 442         while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
 443                         ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
 444                 mb_cache_entry_wait_unused(oe);
 445                 mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
 446         }
 447 }
 448
 449 static int
 450 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 451                                struct ext4_xattr_entry *entry, void *buffer,
 452                                size_t size)
 453 {
 454         u32 hash;
 455
 456         /* Verify stored hash matches calculated hash. */
 457         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 458         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 459                 return -EFSCORRUPTED;
 460
 461         if (entry) {
 462                 __le32 e_hash, tmp_data;
 463
 464                 /* Verify entry hash. */
 465                 tmp_data = cpu_to_le32(hash);
 466                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 467                                                &tmp_data, 1);
 468                 if (e_hash != entry->e_hash)
 469                         return -EFSCORRUPTED;
 470         }
 471         return 0;
 472 }
 473
 474 /*
 475  * Read xattr value from the EA inode.
 476  */
 477 static int
 478 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 479                      void *buffer, size_t size)
 480 {
 481         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 482         struct inode *ea_inode;
 483         int err;
 484
 485         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 486                                     le32_to_cpu(entry->e_hash), &ea_inode);
 487         if (err) {
 488                 ea_inode = NULL;
 489                 goto out;
 490         }
 491
 492         if (i_size_read(ea_inode) != size) {
 493                 ext4_warning_inode(ea_inode,
 494                                    "ea_inode file size=%llu entry size=%zu",
 495                                    i_size_read(ea_inode), size);
 496                 err = -EFSCORRUPTED;
 497                 goto out;
 498         }
 499
 500         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 501         if (err)
 502                 goto out;
 503
 504         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 505                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 506                                                      size);
 507                 if (err) {
 508                         ext4_warning_inode(ea_inode,
 509                                            "EA inode hash validation failed");
 510                         goto out;
 511                 }
 512
 513                 if (ea_inode_cache)
 514                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 515                                         ext4_xattr_inode_get_hash(ea_inode),
 516                                         ea_inode->i_ino, true /* reusable */);
 517         }
 518 out:
 519         iput(ea_inode);
 520         return err;
 521 }
 522
 523 static int
 524 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 525                      void *buffer, size_t buffer_size)
 526 {
 527         struct buffer_head *bh = NULL;
 528         struct ext4_xattr_entry *entry;
 529         size_t size;
 530         void *end;
 531         int error;
 532         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 533
 534         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 535                   name_index, name, buffer, (long)buffer_size);
 536
 537         if (!EXT4_I(inode)->i_file_acl)
 538                 return -ENODATA;
 539         ea_idebug(inode, "reading block %llu",
 540                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 541         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 542         if (IS_ERR(bh))
 543                 return PTR_ERR(bh);
 544         ea_bdebug(bh, "b_count=%d, refcount=%d",
 545                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 546         error = ext4_xattr_check_block(inode, bh);
 547         if (error)
 548                 goto cleanup;
 549         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 550         entry = BFIRST(bh);
 551         end = bh->b_data + bh->b_size;
 552         error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
 553         if (error)
 554                 goto cleanup;
 555         size = le32_to_cpu(entry->e_value_size);
 556         error = -ERANGE;
 557         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 558                 goto cleanup;
 559         if (buffer) {
 560                 if (size > buffer_size)
 561                         goto cleanup;
 562                 if (entry->e_value_inum) {
 563                         error = ext4_xattr_inode_get(inode, entry, buffer,
 564                                                      size);
 565                         if (error)
 566                                 goto cleanup;
 567                 } else {
 568                         u16 offset = le16_to_cpu(entry->e_value_offs);
 569                         void *p = bh->b_data + offset;
 570
 571                         if (unlikely(p + size > end))
 572                                 goto cleanup;
 573                         memcpy(buffer, p, size);
 574                 }
 575         }
 576         error = size;
 577
 578 cleanup:
 579         brelse(bh);
 580         return error;
 581 }
 582
 583 int
 584 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 585                      void *buffer, size_t buffer_size)
 586 {
 587         struct ext4_xattr_ibody_header *header;
 588         struct ext4_xattr_entry *entry;
 589         struct ext4_inode *raw_inode;
 590         struct ext4_iloc iloc;
 591         size_t size;
 592         void *end;
 593         int error;
 594
 595         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 596                 return -ENODATA;
 597         error = ext4_get_inode_loc(inode, &iloc);
 598         if (error)
 599                 return error;
 600         raw_inode = ext4_raw_inode(&iloc);
 601         header = IHDR(inode, raw_inode);
 602         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 603         error = xattr_check_inode(inode, header, end);
 604         if (error)
 605                 goto cleanup;
 606         entry = IFIRST(header);
 607         error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
 608         if (error)
 609                 goto cleanup;
 610         size = le32_to_cpu(entry->e_value_size);
 611         error = -ERANGE;
 612         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 613                 goto cleanup;
 614         if (buffer) {
 615                 if (size > buffer_size)
 616                         goto cleanup;
 617                 if (entry->e_value_inum) {
 618                         error = ext4_xattr_inode_get(inode, entry, buffer,
 619                                                      size);
 620                         if (error)
 621                                 goto cleanup;
 622                 } else {
 623                         u16 offset = le16_to_cpu(entry->e_value_offs);
 624                         void *p = (void *)IFIRST(header) + offset;
 625
 626                         if (unlikely(p + size > end))
 627                                 goto cleanup;
 628                         memcpy(buffer, p, size);
 629                 }
 630         }
 631         error = size;
 632
 633 cleanup:
 634         brelse(iloc.bh);
 635         return error;
 636 }
 637
 638 /*
 639  * ext4_xattr_get()
 640  *
 641  * Copy an extended attribute into the buffer
 642  * provided, or compute the buffer size required.
 643  * Buffer is NULL to compute the size of the buffer required.
 644  *
 645  * Returns a negative error number on failure, or the number of bytes
 646  * used / required on success.
 647  */
 648 int
 649 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 650                void *buffer, size_t buffer_size)
 651 {
 652         int error;
 653
 654         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 655                 return -EIO;
 656
 657         if (strlen(name) > 255)
 658                 return -ERANGE;
 659
 660         down_read(&EXT4_I(inode)->xattr_sem);
 661         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 662                                      buffer_size);
 663         if (error == -ENODATA)
 664                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 665                                              buffer_size);
 666         up_read(&EXT4_I(inode)->xattr_sem);
 667         return error;
 668 }
 669
 670 static int
 671 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 672                         char *buffer, size_t buffer_size)
 673 {
 674         size_t rest = buffer_size;
 675
 676         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 677                 const struct xattr_handler *handler =
 678                         ext4_xattr_handler(entry->e_name_index);
 679
 680                 if (handler && (!handler->list || handler->list(dentry))) {
 681                         const char *prefix = handler->prefix ?: handler->name;
 682                         size_t prefix_len = strlen(prefix);
 683                         size_t size = prefix_len + entry->e_name_len + 1;
 684
 685                         if (buffer) {
 686                                 if (size > rest)
 687                                         return -ERANGE;
 688                                 memcpy(buffer, prefix, prefix_len);
 689                                 buffer += prefix_len;
 690                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 691                                 buffer += entry->e_name_len;
 692                                 *buffer++ = 0;
 693                         }
 694                         rest -= size;
 695                 }
 696         }
 697         return buffer_size - rest;  /* total size */
 698 }
 699
 700 static int
 701 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 702 {
 703         struct inode *inode = d_inode(dentry);
 704         struct buffer_head *bh = NULL;
 705         int error;
 706
 707         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 708                   buffer, (long)buffer_size);
 709
 710         if (!EXT4_I(inode)->i_file_acl)
 711                 return 0;
 712         ea_idebug(inode, "reading block %llu",
 713                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 714         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 715         if (IS_ERR(bh))
 716                 return PTR_ERR(bh);
 717         ea_bdebug(bh, "b_count=%d, refcount=%d",
 718                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 719         error = ext4_xattr_check_block(inode, bh);
 720         if (error)
 721                 goto cleanup;
 722         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 723         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
 724                                         buffer_size);
 725 cleanup:
 726         brelse(bh);
 727         return error;
 728 }
 729
 730 static int
 731 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 732 {
 733         struct inode *inode = d_inode(dentry);
 734         struct ext4_xattr_ibody_header *header;
 735         struct ext4_inode *raw_inode;
 736         struct ext4_iloc iloc;
 737         void *end;
 738         int error;
 739
 740         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 741                 return 0;
 742         error = ext4_get_inode_loc(inode, &iloc);
 743         if (error)
 744                 return error;
 745         raw_inode = ext4_raw_inode(&iloc);
 746         header = IHDR(inode, raw_inode);
 747         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 748         error = xattr_check_inode(inode, header, end);
 749         if (error)
 750                 goto cleanup;
 751         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 752                                         buffer, buffer_size);
 753
 754 cleanup:
 755         brelse(iloc.bh);
 756         return error;
 757 }
 758
 759 /*
 760  * Inode operation listxattr()
 761  *
 762  * d_inode(dentry)->i_rwsem: don't care
 763  *
 764  * Copy a list of attribute names into the buffer
 765  * provided, or compute the buffer size required.
 766  * Buffer is NULL to compute the size of the buffer required.
 767  *
 768  * Returns a negative error number on failure, or the number of bytes
 769  * used / required on success.
 770  */
 771 ssize_t
 772 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 773 {
 774         int ret, ret2;
 775
 776         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 777         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 778         if (ret < 0)
 779                 goto errout;
 780         if (buffer) {
 781                 buffer += ret;
 782                 buffer_size -= ret;
 783         }
 784         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 785         if (ret < 0)
 786                 goto errout;
 787         ret += ret2;
 788 errout:
 789         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 790         return ret;
 791 }
 792
 793 /*
 794  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 795  * not set, set it.
 796  */
 797 static void ext4_xattr_update_super_block(handle_t *handle,
 798                                           struct super_block *sb)
 799 {
 800         if (ext4_has_feature_xattr(sb))
 801                 return;
 802
 803         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 804         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 805                 ext4_set_feature_xattr(sb);
 806                 ext4_handle_dirty_super(handle, sb);
 807         }
 808 }
 809
 810 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 811 {
 812         struct ext4_iloc iloc = { .bh = NULL };
 813         struct buffer_head *bh = NULL;
 814         struct ext4_inode *raw_inode;
 815         struct ext4_xattr_ibody_header *header;
 816         struct ext4_xattr_entry *entry;
 817         qsize_t ea_inode_refs = 0;
 818         void *end;
 819         int ret;
 820
 821         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 822
 823         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 824                 ret = ext4_get_inode_loc(inode, &iloc);
 825                 if (ret)
 826                         goto out;
 827                 raw_inode = ext4_raw_inode(&iloc);
 828                 header = IHDR(inode, raw_inode);
 829                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 830                 ret = xattr_check_inode(inode, header, end);
 831                 if (ret)
 832                         goto out;
 833
 834                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 835                      entry = EXT4_XATTR_NEXT(entry))
 836                         if (entry->e_value_inum)
 837                                 ea_inode_refs++;
 838         }
 839
 840         if (EXT4_I(inode)->i_file_acl) {
 841                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 842                 if (IS_ERR(bh)) {
 843                         ret = PTR_ERR(bh);
 844                         bh = NULL;
 845                         goto out;
 846                 }
 847
 848                 ret = ext4_xattr_check_block(inode, bh);
 849                 if (ret)
 850                         goto out;
 851
 852                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 853                      entry = EXT4_XATTR_NEXT(entry))
 854                         if (entry->e_value_inum)
 855                                 ea_inode_refs++;
 856         }
 857         *usage = ea_inode_refs + 1;
 858         ret = 0;
 859 out:
 860         brelse(iloc.bh);
 861         brelse(bh);
 862         return ret;
 863 }
 864
 865 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 866 {
 867         struct super_block *sb = inode->i_sb;
 868         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 869                                     inode->i_blkbits);
 870         size_t mask = ~(cluster_size - 1);
 871
 872         return (length + cluster_size - 1) & mask;
 873 }
 874
 875 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 876 {
 877         int err;
 878
 879         err = dquot_alloc_inode(inode);
 880         if (err)
 881                 return err;
 882         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 883         if (err)
 884                 dquot_free_inode(inode);
 885         return err;
 886 }
 887
 888 static void ext4_xattr_inode_free_quota(struct inode *parent,
 889                                         struct inode *ea_inode,
 890                                         size_t len)
 891 {
 892         if (ea_inode &&
 893             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 894                 return;
 895         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 896         dquot_free_inode(parent);
 897 }
 898
 899 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 900                              struct buffer_head *block_bh, size_t value_len,
 901                              bool is_create)
 902 {
 903         int credits;
 904         int blocks;
 905
 906         /*
 907          * 1) Owner inode update
 908          * 2) Ref count update on old xattr block
 909          * 3) new xattr block
 910          * 4) block bitmap update for new xattr block
 911          * 5) group descriptor for new xattr block
 912          * 6) block bitmap update for old xattr block
 913          * 7) group descriptor for old block
 914          *
 915          * 6 & 7 can happen if we have two racing threads T_a and T_b
 916          * which are each trying to set an xattr on inodes I_a and I_b
 917          * which were both initially sharing an xattr block.
 918          */
 919         credits = 7;
 920
 921         /* Quota updates. */
 922         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 923
 924         /*
 925          * In case of inline data, we may push out the data to a block,
 926          * so we need to reserve credits for this eventuality
 927          */
 928         if (inode && ext4_has_inline_data(inode))
 929                 credits += ext4_writepage_trans_blocks(inode) + 1;
 930
 931         /* We are done if ea_inode feature is not enabled. */
 932         if (!ext4_has_feature_ea_inode(sb))
 933                 return credits;
 934
 935         /* New ea_inode, inode map, block bitmap, group descriptor. */
 936         credits += 4;
 937
 938         /* Data blocks. */
 939         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 940
 941         /* Indirection block or one level of extent tree. */
 942         blocks += 1;
 943
 944         /* Block bitmap and group descriptor updates for each block. */
 945         credits += blocks * 2;
 946
 947         /* Blocks themselves. */
 948         credits += blocks;
 949
 950         if (!is_create) {
 951                 /* Dereference ea_inode holding old xattr value.
 952                  * Old ea_inode, inode map, block bitmap, group descriptor.
 953                  */
 954                 credits += 4;
 955
 956                 /* Data blocks for old ea_inode. */
 957                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 958
 959                 /* Indirection block or one level of extent tree for old
 960                  * ea_inode.
 961                  */
 962                 blocks += 1;
 963
 964                 /* Block bitmap and group descriptor updates for each block. */
 965                 credits += blocks * 2;
 966         }
 967
 968         /* We may need to clone the existing xattr block in which case we need
 969          * to increment ref counts for existing ea_inodes referenced by it.
 970          */
 971         if (block_bh) {
 972                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 973
 974                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 975                         if (entry->e_value_inum)
 976                                 /* Ref count update on ea_inode. */
 977                                 credits += 1;
 978         }
 979         return credits;
 980 }
 981
 982 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 983                                        int ref_change)
 984 {
 985         struct ext4_iloc iloc;
 986         s64 ref_count;
 987         int ret;
 988
 989         inode_lock(ea_inode);
 990
 991         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
 992         if (ret)
 993                 goto out;
 994
 995         ref_count = ext4_xattr_inode_get_ref(ea_inode);
 996         ref_count += ref_change;
 997         ext4_xattr_inode_set_ref(ea_inode, ref_count);
 998
 999         if (ref_change > 0) {
1000                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1001                           ea_inode->i_ino, ref_count);
1002
1003                 if (ref_count == 1) {
1004                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1005                                   ea_inode->i_ino, ea_inode->i_nlink);
1006
1007                         set_nlink(ea_inode, 1);
1008                         ext4_orphan_del(handle, ea_inode);
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         }
1023
1024         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1025         if (ret)
1026                 ext4_warning_inode(ea_inode,
1027                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1028 out:
1029         inode_unlock(ea_inode);
1030         return ret;
1031 }
1032
1033 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1034 {
1035         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1036 }
1037
1038 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1039 {
1040         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1041 }
1042
1043 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1044                                         struct ext4_xattr_entry *first)
1045 {
1046         struct inode *ea_inode;
1047         struct ext4_xattr_entry *entry;
1048         struct ext4_xattr_entry *failed_entry;
1049         unsigned int ea_ino;
1050         int err, saved_err;
1051
1052         for (entry = first; !IS_LAST_ENTRY(entry);
1053              entry = EXT4_XATTR_NEXT(entry)) {
1054                 if (!entry->e_value_inum)
1055                         continue;
1056                 ea_ino = le32_to_cpu(entry->e_value_inum);
1057                 err = ext4_xattr_inode_iget(parent, ea_ino,
1058                                             le32_to_cpu(entry->e_hash),
1059                                             &ea_inode);
1060                 if (err)
1061                         goto cleanup;
1062                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1063                 if (err) {
1064                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1065                         iput(ea_inode);
1066                         goto cleanup;
1067                 }
1068                 iput(ea_inode);
1069         }
1070         return 0;
1071
1072 cleanup:
1073         saved_err = err;
1074         failed_entry = entry;
1075
1076         for (entry = first; entry != failed_entry;
1077              entry = EXT4_XATTR_NEXT(entry)) {
1078                 if (!entry->e_value_inum)
1079                         continue;
1080                 ea_ino = le32_to_cpu(entry->e_value_inum);
1081                 err = ext4_xattr_inode_iget(parent, ea_ino,
1082                                             le32_to_cpu(entry->e_hash),
1083                                             &ea_inode);
1084                 if (err) {
1085                         ext4_warning(parent->i_sb,
1086                                      "cleanup ea_ino %u iget error %d", ea_ino,
1087                                      err);
1088                         continue;
1089                 }
1090                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1091                 if (err)
1092                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1093                                            err);
1094                 iput(ea_inode);
1095         }
1096         return saved_err;
1097 }
1098
1099 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1100                         struct buffer_head *bh, bool block_csum, bool dirty)
1101 {
1102         int error;
1103
1104         if (bh && dirty) {
1105                 if (block_csum)
1106                         ext4_xattr_block_csum_set(inode, bh);
1107                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1108                 if (error) {
1109                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1110                                      error);
1111                         return error;
1112                 }
1113         }
1114         return 0;
1115 }
1116
1117 static void
1118 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1119                              struct buffer_head *bh,
1120                              struct ext4_xattr_entry *first, bool block_csum,
1121                              struct ext4_xattr_inode_array **ea_inode_array,
1122                              int extra_credits, bool skip_quota)
1123 {
1124         struct inode *ea_inode;
1125         struct ext4_xattr_entry *entry;
1126         bool dirty = false;
1127         unsigned int ea_ino;
1128         int err;
1129         int credits;
1130
1131         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1132         credits = 2 + extra_credits;
1133
1134         for (entry = first; !IS_LAST_ENTRY(entry);
1135              entry = EXT4_XATTR_NEXT(entry)) {
1136                 if (!entry->e_value_inum)
1137                         continue;
1138                 ea_ino = le32_to_cpu(entry->e_value_inum);
1139                 err = ext4_xattr_inode_iget(parent, ea_ino,
1140                                             le32_to_cpu(entry->e_hash),
1141                                             &ea_inode);
1142                 if (err)
1143                         continue;
1144
1145                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1146                 if (err) {
1147                         ext4_warning_inode(ea_inode,
1148                                            "Expand inode array err=%d", err);
1149                         iput(ea_inode);
1150                         continue;
1151                 }
1152
1153                 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1154                         ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1155                         ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1156                                               dirty));
1157                 if (err < 0) {
1158                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1159                                            err);
1160                         continue;
1161                 }
1162                 if (err > 0) {
1163                         err = ext4_journal_get_write_access(handle, bh);
1164                         if (err) {
1165                                 ext4_warning_inode(ea_inode,
1166                                                 "Re-get write access err=%d",
1167                                                 err);
1168                                 continue;
1169                         }
1170                 }
1171
1172                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1173                 if (err) {
1174                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1175                                            err);
1176                         continue;
1177                 }
1178
1179                 if (!skip_quota)
1180                         ext4_xattr_inode_free_quota(parent, ea_inode,
1181                                               le32_to_cpu(entry->e_value_size));
1182
1183                 /*
1184                  * Forget about ea_inode within the same transaction that
1185                  * decrements the ref count. This avoids duplicate decrements in
1186                  * case the rest of the work spills over to subsequent
1187                  * transactions.
1188                  */
1189                 entry->e_value_inum = 0;
1190                 entry->e_value_size = 0;
1191
1192                 dirty = true;
1193         }
1194
1195         if (dirty) {
1196                 /*
1197                  * Note that we are deliberately skipping csum calculation for
1198                  * the final update because we do not expect any journal
1199                  * restarts until xattr block is freed.
1200                  */
1201
1202                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1203                 if (err)
1204                         ext4_warning_inode(parent,
1205                                            "handle dirty metadata err=%d", err);
1206         }
1207 }
1208
1209 /*
1210  * Release the xattr block BH: If the reference count is > 1, decrement it;
1211  * otherwise free the block.
1212  */
1213 static void
1214 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1215                          struct buffer_head *bh,
1216                          struct ext4_xattr_inode_array **ea_inode_array,
1217                          int extra_credits)
1218 {
1219         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1220         u32 hash, ref;
1221         int error = 0;
1222
1223         BUFFER_TRACE(bh, "get_write_access");
1224         error = ext4_journal_get_write_access(handle, bh);
1225         if (error)
1226                 goto out;
1227
1228 retry_ref:
1229         lock_buffer(bh);
1230         hash = le32_to_cpu(BHDR(bh)->h_hash);
1231         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1232         if (ref == 1) {
1233                 ea_bdebug(bh, "refcount now=0; freeing");
1234                 /*
1235                  * This must happen under buffer lock for
1236                  * ext4_xattr_block_set() to reliably detect freed block
1237                  */
1238                 if (ea_block_cache) {
1239                         struct mb_cache_entry *oe;
1240
1241                         oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
1242                                                           bh->b_blocknr);
1243                         if (oe) {
1244                                 unlock_buffer(bh);
1245                                 mb_cache_entry_wait_unused(oe);
1246                                 mb_cache_entry_put(ea_block_cache, oe);
1247                                 goto retry_ref;
1248                         }
1249                 }
1250                 get_bh(bh);
1251                 unlock_buffer(bh);
1252
1253                 if (ext4_has_feature_ea_inode(inode->i_sb))
1254                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1255                                                      BFIRST(bh),
1256                                                      true /* block_csum */,
1257                                                      ea_inode_array,
1258                                                      extra_credits,
1259                                                      true /* skip_quota */);
1260                 ext4_free_blocks(handle, inode, bh, 0, 1,
1261                                  EXT4_FREE_BLOCKS_METADATA |
1262                                  EXT4_FREE_BLOCKS_FORGET);
1263         } else {
1264                 ref--;
1265                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1266                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1267                         struct mb_cache_entry *ce;
1268
1269                         if (ea_block_cache) {
1270                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1271                                                         bh->b_blocknr);
1272                                 if (ce) {
1273                                         set_bit(MBE_REUSABLE_B, &ce->e_flags);
1274                                         mb_cache_entry_put(ea_block_cache, ce);
1275                                 }
1276                         }
1277                 }
1278
1279                 ext4_xattr_block_csum_set(inode, bh);
1280                 /*
1281                  * Beware of this ugliness: Releasing of xattr block references
1282                  * from different inodes can race and so we have to protect
1283                  * from a race where someone else frees the block (and releases
1284                  * its journal_head) before we are done dirtying the buffer. In
1285                  * nojournal mode this race is harmless and we actually cannot
1286                  * call ext4_handle_dirty_metadata() with locked buffer as
1287                  * that function can call sync_dirty_buffer() so for that case
1288                  * we handle the dirtying after unlocking the buffer.
1289                  */
1290                 if (ext4_handle_valid(handle))
1291                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1292                 unlock_buffer(bh);
1293                 if (!ext4_handle_valid(handle))
1294                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1295                 if (IS_SYNC(inode))
1296                         ext4_handle_sync(handle);
1297                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1298                 ea_bdebug(bh, "refcount now=%d; releasing",
1299                           le32_to_cpu(BHDR(bh)->h_refcount));
1300         }
1301 out:
1302         ext4_std_error(inode->i_sb, error);
1303         return;
1304 }
1305
1306 /*
1307  * Find the available free space for EAs. This also returns the total number of
1308  * bytes used by EA entries.
1309  */
1310 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1311                                     size_t *min_offs, void *base, int *total)
1312 {
1313         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1314                 if (!last->e_value_inum && last->e_value_size) {
1315                         size_t offs = le16_to_cpu(last->e_value_offs);
1316                         if (offs < *min_offs)
1317                                 *min_offs = offs;
1318                 }
1319                 if (total)
1320                         *total += EXT4_XATTR_LEN(last->e_name_len);
1321         }
1322         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1323 }
1324
1325 /*
1326  * Write the value of the EA in an inode.
1327  */
1328 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1329                                   const void *buf, int bufsize)
1330 {
1331         struct buffer_head *bh = NULL;
1332         unsigned long block = 0;
1333         int blocksize = ea_inode->i_sb->s_blocksize;
1334         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1335         int csize, wsize = 0;
1336         int ret = 0, ret2 = 0;
1337         int retries = 0;
1338
1339 retry:
1340         while (ret >= 0 && ret < max_blocks) {
1341                 struct ext4_map_blocks map;
1342                 map.m_lblk = block += ret;
1343                 map.m_len = max_blocks -= ret;
1344
1345                 ret = ext4_map_blocks(handle, ea_inode, &map,
1346                                       EXT4_GET_BLOCKS_CREATE);
1347                 if (ret <= 0) {
1348                         ext4_mark_inode_dirty(handle, ea_inode);
1349                         if (ret == -ENOSPC &&
1350                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1351                                 ret = 0;
1352                                 goto retry;
1353                         }
1354                         break;
1355                 }
1356         }
1357
1358         if (ret < 0)
1359                 return ret;
1360
1361         block = 0;
1362         while (wsize < bufsize) {
1363                 brelse(bh);
1364                 csize = (bufsize - wsize) > blocksize ? blocksize :
1365                                                                 bufsize - wsize;
1366                 bh = ext4_getblk(handle, ea_inode, block, 0);
1367                 if (IS_ERR(bh))
1368                         return PTR_ERR(bh);
1369                 if (!bh) {
1370                         WARN_ON_ONCE(1);
1371                         EXT4_ERROR_INODE(ea_inode,
1372                                          "ext4_getblk() return bh = NULL");
1373                         return -EFSCORRUPTED;
1374                 }
1375                 ret = ext4_journal_get_write_access(handle, bh);
1376                 if (ret)
1377                         goto out;
1378
1379                 memcpy(bh->b_data, buf, csize);
1380                 set_buffer_uptodate(bh);
1381                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1382
1383                 buf += csize;
1384                 wsize += csize;
1385                 block += 1;
1386         }
1387
1388         inode_lock(ea_inode);
1389         i_size_write(ea_inode, wsize);
1390         ext4_update_i_disksize(ea_inode, wsize);
1391         inode_unlock(ea_inode);
1392
1393         ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1394         if (unlikely(ret2 && !ret))
1395                 ret = ret2;
1396
1397 out:
1398         brelse(bh);
1399
1400         return ret;
1401 }
1402
1403 /*
1404  * Create an inode to store the value of a large EA.
1405  */
1406 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1407                                              struct inode *inode, u32 hash)
1408 {
1409         struct inode *ea_inode = NULL;
1410         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1411         int err;
1412
1413         if (inode->i_sb->s_root == NULL) {
1414                 ext4_warning(inode->i_sb,
1415                              "refuse to create EA inode when umounting");
1416                 WARN_ON(1);
1417                 return ERR_PTR(-EINVAL);
1418         }
1419
1420         /*
1421          * Let the next inode be the goal, so we try and allocate the EA inode
1422          * in the same group, or nearby one.
1423          */
1424         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1425                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1426                                   EXT4_EA_INODE_FL);
1427         if (!IS_ERR(ea_inode)) {
1428                 ea_inode->i_op = &ext4_file_inode_operations;
1429                 ea_inode->i_fop = &ext4_file_operations;
1430                 ext4_set_aops(ea_inode);
1431                 ext4_xattr_inode_set_class(ea_inode);
1432                 unlock_new_inode(ea_inode);
1433                 ext4_xattr_inode_set_ref(ea_inode, 1);
1434                 ext4_xattr_inode_set_hash(ea_inode, hash);
1435                 err = ext4_mark_inode_dirty(handle, ea_inode);
1436                 if (!err)
1437                         err = ext4_inode_attach_jinode(ea_inode);
1438                 if (err) {
1439                         if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1440                                 ext4_warning_inode(ea_inode,
1441                                         "cleanup dec ref error %d", err);
1442                         iput(ea_inode);
1443                         return ERR_PTR(err);
1444                 }
1445
1446                 /*
1447                  * Xattr inodes are shared therefore quota charging is performed
1448                  * at a higher level.
1449                  */
1450                 dquot_free_inode(ea_inode);
1451                 dquot_drop(ea_inode);
1452                 inode_lock(ea_inode);
1453                 ea_inode->i_flags |= S_NOQUOTA;
1454                 inode_unlock(ea_inode);
1455         }
1456
1457         return ea_inode;
1458 }
1459
1460 static struct inode *
1461 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1462                             size_t value_len, u32 hash)
1463 {
1464         struct inode *ea_inode;
1465         struct mb_cache_entry *ce;
1466         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1467         void *ea_data;
1468
1469         if (!ea_inode_cache)
1470                 return NULL;
1471
1472         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1473         if (!ce)
1474                 return NULL;
1475
1476         WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1477                      !(current->flags & PF_MEMALLOC_NOFS));
1478
1479         ea_data = kvmalloc(value_len, GFP_KERNEL);
1480         if (!ea_data) {
1481                 mb_cache_entry_put(ea_inode_cache, ce);
1482                 return NULL;
1483         }
1484
1485         while (ce) {
1486                 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1487                                      EXT4_IGET_EA_INODE);
1488                 if (IS_ERR(ea_inode))
1489                         goto next_entry;
1490                 ext4_xattr_inode_set_class(ea_inode);
1491                 if (i_size_read(ea_inode) == value_len &&
1492                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1493                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1494                                                     value_len) &&
1495                     !memcmp(value, ea_data, value_len)) {
1496                         mb_cache_entry_touch(ea_inode_cache, ce);
1497                         mb_cache_entry_put(ea_inode_cache, ce);
1498                         kvfree(ea_data);
1499                         return ea_inode;
1500                 }
1501                 iput(ea_inode);
1502         next_entry:
1503                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1504         }
1505         kvfree(ea_data);
1506         return NULL;
1507 }
1508
1509 /*
1510  * Add value of the EA in an inode.
1511  */
1512 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1513                                           const void *value, size_t value_len,
1514                                           struct inode **ret_inode)
1515 {
1516         struct inode *ea_inode;
1517         u32 hash;
1518         int err;
1519
1520         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1521         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1522         if (ea_inode) {
1523                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1524                 if (err) {
1525                         iput(ea_inode);
1526                         return err;
1527                 }
1528
1529                 *ret_inode = ea_inode;
1530                 return 0;
1531         }
1532
1533         /* Create an inode for the EA value */
1534         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1535         if (IS_ERR(ea_inode))
1536                 return PTR_ERR(ea_inode);
1537
1538         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1539         if (err) {
1540                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1541                 iput(ea_inode);
1542                 return err;
1543         }
1544
1545         if (EA_INODE_CACHE(inode))
1546                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1547                                       ea_inode->i_ino, true /* reusable */);
1548
1549         *ret_inode = ea_inode;
1550         return 0;
1551 }
1552
1553 /*
1554  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1555  * feature is enabled.
1556  */
1557 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1558
1559 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1560                                 struct ext4_xattr_search *s,
1561                                 handle_t *handle, struct inode *inode,
1562                                 bool is_block)
1563 {
1564         struct ext4_xattr_entry *last, *next;
1565         struct ext4_xattr_entry *here = s->here;
1566         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1567         int in_inode = i->in_inode;
1568         struct inode *old_ea_inode = NULL;
1569         struct inode *new_ea_inode = NULL;
1570         size_t old_size, new_size;
1571         int ret;
1572
1573         /* Space used by old and new values. */
1574         old_size = (!s->not_found && !here->e_value_inum) ?
1575                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1576         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1577
1578         /*
1579          * Optimization for the simple case when old and new values have the
1580          * same padded sizes. Not applicable if external inodes are involved.
1581          */
1582         if (new_size && new_size == old_size) {
1583                 size_t offs = le16_to_cpu(here->e_value_offs);
1584                 void *val = s->base + offs;
1585
1586                 here->e_value_size = cpu_to_le32(i->value_len);
1587                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1588                         memset(val, 0, new_size);
1589                 } else {
1590                         memcpy(val, i->value, i->value_len);
1591                         /* Clear padding bytes. */
1592                         memset(val + i->value_len, 0, new_size - i->value_len);
1593                 }
1594                 goto update_hash;
1595         }
1596
1597         /* Compute min_offs and last. */
1598         last = s->first;
1599         for (; !IS_LAST_ENTRY(last); last = next) {
1600                 next = EXT4_XATTR_NEXT(last);
1601                 if ((void *)next >= s->end) {
1602                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1603                         ret = -EFSCORRUPTED;
1604                         goto out;
1605                 }
1606                 if (!last->e_value_inum && last->e_value_size) {
1607                         size_t offs = le16_to_cpu(last->e_value_offs);
1608                         if (offs < min_offs)
1609                                 min_offs = offs;
1610                 }
1611         }
1612
1613         /* Check whether we have enough space. */
1614         if (i->value) {
1615                 size_t free;
1616
1617                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1618                 if (!s->not_found)
1619                         free += EXT4_XATTR_LEN(name_len) + old_size;
1620
1621                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1622                         ret = -ENOSPC;
1623                         goto out;
1624                 }
1625
1626                 /*
1627                  * If storing the value in an external inode is an option,
1628                  * reserve space for xattr entries/names in the external
1629                  * attribute block so that a long value does not occupy the
1630                  * whole space and prevent further entries being added.
1631                  */
1632                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1633                     new_size && is_block &&
1634                     (min_offs + old_size - new_size) <
1635                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1636                         ret = -ENOSPC;
1637                         goto out;
1638                 }
1639         }
1640
1641         /*
1642          * Getting access to old and new ea inodes is subject to failures.
1643          * Finish that work before doing any modifications to the xattr data.
1644          */
1645         if (!s->not_found && here->e_value_inum) {
1646                 ret = ext4_xattr_inode_iget(inode,
1647                                             le32_to_cpu(here->e_value_inum),
1648                                             le32_to_cpu(here->e_hash),
1649                                             &old_ea_inode);
1650                 if (ret) {
1651                         old_ea_inode = NULL;
1652                         goto out;
1653                 }
1654         }
1655         if (i->value && in_inode) {
1656                 WARN_ON_ONCE(!i->value_len);
1657
1658                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1659                 if (ret)
1660                         goto out;
1661
1662                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1663                                                      i->value_len,
1664                                                      &new_ea_inode);
1665                 if (ret) {
1666                         new_ea_inode = NULL;
1667                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1668                         goto out;
1669                 }
1670         }
1671
1672         if (old_ea_inode) {
1673                 /* We are ready to release ref count on the old_ea_inode. */
1674                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1675                 if (ret) {
1676                         /* Release newly required ref count on new_ea_inode. */
1677                         if (new_ea_inode) {
1678                                 int err;
1679
1680                                 err = ext4_xattr_inode_dec_ref(handle,
1681                                                                new_ea_inode);
1682                                 if (err)
1683                                         ext4_warning_inode(new_ea_inode,
1684                                                   "dec ref new_ea_inode err=%d",
1685                                                   err);
1686                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1687                                                             i->value_len);
1688                         }
1689                         goto out;
1690                 }
1691
1692                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1693                                             le32_to_cpu(here->e_value_size));
1694         }
1695
1696         /* No failures allowed past this point. */
1697
1698         if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1699                 /* Remove the old value. */
1700                 void *first_val = s->base + min_offs;
1701                 size_t offs = le16_to_cpu(here->e_value_offs);
1702                 void *val = s->base + offs;
1703
1704                 memmove(first_val + old_size, first_val, val - first_val);
1705                 memset(first_val, 0, old_size);
1706                 min_offs += old_size;
1707
1708                 /* Adjust all value offsets. */
1709                 last = s->first;
1710                 while (!IS_LAST_ENTRY(last)) {
1711                         size_t o = le16_to_cpu(last->e_value_offs);
1712
1713                         if (!last->e_value_inum &&
1714                             last->e_value_size && o < offs)
1715                                 last->e_value_offs = cpu_to_le16(o + old_size);
1716                         last = EXT4_XATTR_NEXT(last);
1717                 }
1718         }
1719
1720         if (!i->value) {
1721                 /* Remove old name. */
1722                 size_t size = EXT4_XATTR_LEN(name_len);
1723
1724                 last = ENTRY((void *)last - size);
1725                 memmove(here, (void *)here + size,
1726                         (void *)last - (void *)here + sizeof(__u32));
1727                 memset(last, 0, size);
1728
1729                 /*
1730                  * Update i_inline_off - moved ibody region might contain
1731                  * system.data attribute.  Handling a failure here won't
1732                  * cause other complications for setting an xattr.
1733                  */
1734                 if (!is_block && ext4_has_inline_data(inode)) {
1735                         ret = ext4_find_inline_data_nolock(inode);
1736                         if (ret) {
1737                                 ext4_warning_inode(inode,
1738                                         "unable to update i_inline_off");
1739                                 goto out;
1740                         }
1741                 }
1742         } else if (s->not_found) {
1743                 /* Insert new name. */
1744                 size_t size = EXT4_XATTR_LEN(name_len);
1745                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1746
1747                 memmove((void *)here + size, here, rest);
1748                 memset(here, 0, size);
1749                 here->e_name_index = i->name_index;
1750                 here->e_name_len = name_len;
1751                 memcpy(here->e_name, i->name, name_len);
1752         } else {
1753                 /* This is an update, reset value info. */
1754                 here->e_value_inum = 0;
1755                 here->e_value_offs = 0;
1756                 here->e_value_size = 0;
1757         }
1758
1759         if (i->value) {
1760                 /* Insert new value. */
1761                 if (in_inode) {
1762                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1763                 } else if (i->value_len) {
1764                         void *val = s->base + min_offs - new_size;
1765
1766                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1767                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1768                                 memset(val, 0, new_size);
1769                         } else {
1770                                 memcpy(val, i->value, i->value_len);
1771                                 /* Clear padding bytes. */
1772                                 memset(val + i->value_len, 0,
1773                                        new_size - i->value_len);
1774                         }
1775                 }
1776                 here->e_value_size = cpu_to_le32(i->value_len);
1777         }
1778
1779 update_hash:
1780         if (i->value) {
1781                 __le32 hash = 0;
1782
1783                 /* Entry hash calculation. */
1784                 if (in_inode) {
1785                         __le32 crc32c_hash;
1786
1787                         /*
1788                          * Feed crc32c hash instead of the raw value for entry
1789                          * hash calculation. This is to avoid walking
1790                          * potentially long value buffer again.
1791                          */
1792                         crc32c_hash = cpu_to_le32(
1793                                        ext4_xattr_inode_get_hash(new_ea_inode));
1794                         hash = ext4_xattr_hash_entry(here->e_name,
1795                                                      here->e_name_len,
1796                                                      &crc32c_hash, 1);
1797                 } else if (is_block) {
1798                         __le32 *value = s->base + le16_to_cpu(
1799                                                         here->e_value_offs);
1800
1801                         hash = ext4_xattr_hash_entry(here->e_name,
1802                                                      here->e_name_len, value,
1803                                                      new_size >> 2);
1804                 }
1805                 here->e_hash = hash;
1806         }
1807
1808         if (is_block)
1809                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1810
1811         ret = 0;
1812 out:
1813         iput(old_ea_inode);
1814         iput(new_ea_inode);
1815         return ret;
1816 }
1817
1818 struct ext4_xattr_block_find {
1819         struct ext4_xattr_search s;
1820         struct buffer_head *bh;
1821 };
1822
1823 static int
1824 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1825                       struct ext4_xattr_block_find *bs)
1826 {
1827         struct super_block *sb = inode->i_sb;
1828         int error;
1829
1830         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1831                   i->name_index, i->name, i->value, (long)i->value_len);
1832
1833         if (EXT4_I(inode)->i_file_acl) {
1834                 /* The inode already has an extended attribute block. */
1835                 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1836                 if (IS_ERR(bs->bh)) {
1837                         error = PTR_ERR(bs->bh);
1838                         bs->bh = NULL;
1839                         return error;
1840                 }
1841                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1842                         atomic_read(&(bs->bh->b_count)),
1843                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1844                 error = ext4_xattr_check_block(inode, bs->bh);
1845                 if (error)
1846                         return error;
1847                 /* Find the named attribute. */
1848                 bs->s.base = BHDR(bs->bh);
1849                 bs->s.first = BFIRST(bs->bh);
1850                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1851                 bs->s.here = bs->s.first;
1852                 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1853                                          i->name_index, i->name, 1);
1854                 if (error && error != -ENODATA)
1855                         return error;
1856                 bs->s.not_found = error;
1857         }
1858         return 0;
1859 }
1860
1861 static int
1862 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1863                      struct ext4_xattr_info *i,
1864                      struct ext4_xattr_block_find *bs)
1865 {
1866         struct super_block *sb = inode->i_sb;
1867         struct buffer_head *new_bh = NULL;
1868         struct ext4_xattr_search s_copy = bs->s;
1869         struct ext4_xattr_search *s = &s_copy;
1870         struct mb_cache_entry *ce = NULL;
1871         int error = 0;
1872         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1873         struct inode *ea_inode = NULL, *tmp_inode;
1874         size_t old_ea_inode_quota = 0;
1875         unsigned int ea_ino;
1876
1877
1878 #define header(x) ((struct ext4_xattr_header *)(x))
1879
1880         if (s->base) {
1881                 int offset = (char *)s->here - bs->bh->b_data;
1882
1883                 BUFFER_TRACE(bs->bh, "get_write_access");
1884                 error = ext4_journal_get_write_access(handle, bs->bh);
1885                 if (error)
1886                         goto cleanup;
1887                 lock_buffer(bs->bh);
1888
1889                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1890                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1891
1892                         /*
1893                          * This must happen under buffer lock for
1894                          * ext4_xattr_block_set() to reliably detect modified
1895                          * block
1896                          */
1897                         if (ea_block_cache) {
1898                                 struct mb_cache_entry *oe;
1899
1900                                 oe = mb_cache_entry_delete_or_get(ea_block_cache,
1901                                         hash, bs->bh->b_blocknr);
1902                                 if (oe) {
1903                                         /*
1904                                          * Xattr block is getting reused. Leave
1905                                          * it alone.
1906                                          */
1907                                         mb_cache_entry_put(ea_block_cache, oe);
1908                                         goto clone_block;
1909                                 }
1910                         }
1911                         ea_bdebug(bs->bh, "modifying in-place");
1912                         error = ext4_xattr_set_entry(i, s, handle, inode,
1913                                                      true /* is_block */);
1914                         ext4_xattr_block_csum_set(inode, bs->bh);
1915                         unlock_buffer(bs->bh);
1916                         if (error == -EFSCORRUPTED)
1917                                 goto bad_block;
1918                         if (!error)
1919                                 error = ext4_handle_dirty_metadata(handle,
1920                                                                    inode,
1921                                                                    bs->bh);
1922                         if (error)
1923                                 goto cleanup;
1924                         goto inserted;
1925                 }
1926 clone_block:
1927                 unlock_buffer(bs->bh);
1928                 ea_bdebug(bs->bh, "cloning");
1929                 s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
1930                 error = -ENOMEM;
1931                 if (s->base == NULL)
1932                         goto cleanup;
1933                 s->first = ENTRY(header(s->base)+1);
1934                 header(s->base)->h_refcount = cpu_to_le32(1);
1935                 s->here = ENTRY(s->base + offset);
1936                 s->end = s->base + bs->bh->b_size;
1937
1938                 /*
1939                  * If existing entry points to an xattr inode, we need
1940                  * to prevent ext4_xattr_set_entry() from decrementing
1941                  * ref count on it because the reference belongs to the
1942                  * original block. In this case, make the entry look
1943                  * like it has an empty value.
1944                  */
1945                 if (!s->not_found && s->here->e_value_inum) {
1946                         ea_ino = le32_to_cpu(s->here->e_value_inum);
1947                         error = ext4_xattr_inode_iget(inode, ea_ino,
1948                                       le32_to_cpu(s->here->e_hash),
1949                                       &tmp_inode);
1950                         if (error)
1951                                 goto cleanup;
1952
1953                         if (!ext4_test_inode_state(tmp_inode,
1954                                         EXT4_STATE_LUSTRE_EA_INODE)) {
1955                                 /*
1956                                  * Defer quota free call for previous
1957                                  * inode until success is guaranteed.
1958                                  */
1959                                 old_ea_inode_quota = le32_to_cpu(
1960                                                 s->here->e_value_size);
1961                         }
1962                         iput(tmp_inode);
1963
1964                         s->here->e_value_inum = 0;
1965                         s->here->e_value_size = 0;
1966                 }
1967         } else {
1968                 /* Allocate a buffer where we construct the new block. */
1969                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1970                 /* assert(header == s->base) */
1971                 error = -ENOMEM;
1972                 if (s->base == NULL)
1973                         goto cleanup;
1974                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1975                 header(s->base)->h_blocks = cpu_to_le32(1);
1976                 header(s->base)->h_refcount = cpu_to_le32(1);
1977                 s->first = ENTRY(header(s->base)+1);
1978                 s->here = ENTRY(header(s->base)+1);
1979                 s->end = s->base + sb->s_blocksize;
1980         }
1981
1982         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1983         if (error == -EFSCORRUPTED)
1984                 goto bad_block;
1985         if (error)
1986                 goto cleanup;
1987
1988         if (i->value && s->here->e_value_inum) {
1989                 /*
1990                  * A ref count on ea_inode has been taken as part of the call to
1991                  * ext4_xattr_set_entry() above. We would like to drop this
1992                  * extra ref but we have to wait until the xattr block is
1993                  * initialized and has its own ref count on the ea_inode.
1994                  */
1995                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1996                 error = ext4_xattr_inode_iget(inode, ea_ino,
1997                                               le32_to_cpu(s->here->e_hash),
1998                                               &ea_inode);
1999                 if (error) {
2000                         ea_inode = NULL;
2001                         goto cleanup;
2002                 }
2003         }
2004
2005 inserted:
2006         if (!IS_LAST_ENTRY(s->first)) {
2007                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
2008                                                      &ce);
2009                 if (new_bh) {
2010                         /* We found an identical block in the cache. */
2011                         if (new_bh == bs->bh)
2012                                 ea_bdebug(new_bh, "keeping");
2013                         else {
2014                                 u32 ref;
2015
2016 #ifdef EXT4_XATTR_DEBUG
2017                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
2018 #endif
2019                                 /* The old block is released after updating
2020                                    the inode. */
2021                                 error = dquot_alloc_block(inode,
2022                                                 EXT4_C2B(EXT4_SB(sb), 1));
2023                                 if (error)
2024                                         goto cleanup;
2025                                 BUFFER_TRACE(new_bh, "get_write_access");
2026                                 error = ext4_journal_get_write_access(handle,
2027                                                                       new_bh);
2028                                 if (error)
2029                                         goto cleanup_dquot;
2030                                 lock_buffer(new_bh);
2031                                 /*
2032                                  * We have to be careful about races with
2033                                  * adding references to xattr block. Once we
2034                                  * hold buffer lock xattr block's state is
2035                                  * stable so we can check the additional
2036                                  * reference fits.
2037                                  */
2038                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2039                                 if (ref > EXT4_XATTR_REFCOUNT_MAX) {
2040                                         /*
2041                                          * Undo everything and check mbcache
2042                                          * again.
2043                                          */
2044                                         unlock_buffer(new_bh);
2045                                         dquot_free_block(inode,
2046                                                          EXT4_C2B(EXT4_SB(sb),
2047                                                                   1));
2048                                         brelse(new_bh);
2049                                         mb_cache_entry_put(ea_block_cache, ce);
2050                                         ce = NULL;
2051                                         new_bh = NULL;
2052                                         goto inserted;
2053                                 }
2054                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2055                                 if (ref == EXT4_XATTR_REFCOUNT_MAX)
2056                                         clear_bit(MBE_REUSABLE_B, &ce->e_flags);
2057                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2058                                           ref);
2059                                 ext4_xattr_block_csum_set(inode, new_bh);
2060                                 unlock_buffer(new_bh);
2061                                 error = ext4_handle_dirty_metadata(handle,
2062                                                                    inode,
2063                                                                    new_bh);
2064                                 if (error)
2065                                         goto cleanup_dquot;
2066                         }
2067                         mb_cache_entry_touch(ea_block_cache, ce);
2068                         mb_cache_entry_put(ea_block_cache, ce);
2069                         ce = NULL;
2070                 } else if (bs->bh && s->base == bs->bh->b_data) {
2071                         /* We were modifying this block in-place. */
2072                         ea_bdebug(bs->bh, "keeping this block");
2073                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2074                         new_bh = bs->bh;
2075                         get_bh(new_bh);
2076                 } else {
2077                         /* We need to allocate a new block */
2078                         ext4_fsblk_t goal, block;
2079
2080 #ifdef EXT4_XATTR_DEBUG
2081                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2082 #endif
2083                         goal = ext4_group_first_block_no(sb,
2084                                                 EXT4_I(inode)->i_block_group);
2085                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2086                                                      NULL, &error);
2087                         if (error)
2088                                 goto cleanup;
2089
2090                         ea_idebug(inode, "creating block %llu",
2091                                   (unsigned long long)block);
2092
2093                         new_bh = sb_getblk(sb, block);
2094                         if (unlikely(!new_bh)) {
2095                                 error = -ENOMEM;
2096 getblk_failed:
2097                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2098                                                  EXT4_FREE_BLOCKS_METADATA);
2099                                 goto cleanup;
2100                         }
2101                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2102                                                       ENTRY(header(s->base)+1));
2103                         if (error)
2104                                 goto getblk_failed;
2105                         if (ea_inode) {
2106                                 /* Drop the extra ref on ea_inode. */
2107                                 error = ext4_xattr_inode_dec_ref(handle,
2108                                                                  ea_inode);
2109                                 if (error)
2110                                         ext4_warning_inode(ea_inode,
2111                                                            "dec ref error=%d",
2112                                                            error);
2113                                 iput(ea_inode);
2114                                 ea_inode = NULL;
2115                         }
2116
2117                         lock_buffer(new_bh);
2118                         error = ext4_journal_get_create_access(handle, new_bh);
2119                         if (error) {
2120                                 unlock_buffer(new_bh);
2121                                 error = -EIO;
2122                                 goto getblk_failed;
2123                         }
2124                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2125                         ext4_xattr_block_csum_set(inode, new_bh);
2126                         set_buffer_uptodate(new_bh);
2127                         unlock_buffer(new_bh);
2128                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2129                         error = ext4_handle_dirty_metadata(handle, inode,
2130                                                            new_bh);
2131                         if (error)
2132                                 goto cleanup;
2133                 }
2134         }
2135
2136         if (old_ea_inode_quota)
2137                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2138
2139         /* Update the inode. */
2140         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2141
2142         /* Drop the previous xattr block. */
2143         if (bs->bh && bs->bh != new_bh) {
2144                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2145
2146                 ext4_xattr_release_block(handle, inode, bs->bh,
2147                                          &ea_inode_array,
2148                                          0 /* extra_credits */);
2149                 ext4_xattr_inode_array_free(ea_inode_array);
2150         }
2151         error = 0;
2152
2153 cleanup:
2154         if (ea_inode) {
2155                 int error2;
2156
2157                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2158                 if (error2)
2159                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2160                                            error2);
2161
2162                 /* If there was an error, revert the quota charge. */
2163                 if (error)
2164                         ext4_xattr_inode_free_quota(inode, ea_inode,
2165                                                     i_size_read(ea_inode));
2166                 iput(ea_inode);
2167         }
2168         if (ce)
2169                 mb_cache_entry_put(ea_block_cache, ce);
2170         brelse(new_bh);
2171         if (!(bs->bh && s->base == bs->bh->b_data))
2172                 kfree(s->base);
2173
2174         return error;
2175
2176 cleanup_dquot:
2177         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2178         goto cleanup;
2179
2180 bad_block:
2181         EXT4_ERROR_INODE(inode, "bad block %llu",
2182                          EXT4_I(inode)->i_file_acl);
2183         goto cleanup;
2184
2185 #undef header
2186 }
2187
2188 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2189                           struct ext4_xattr_ibody_find *is)
2190 {
2191         struct ext4_xattr_ibody_header *header;
2192         struct ext4_inode *raw_inode;
2193         int error;
2194
2195         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2196                 return 0;
2197
2198         raw_inode = ext4_raw_inode(&is->iloc);
2199         header = IHDR(inode, raw_inode);
2200         is->s.base = is->s.first = IFIRST(header);
2201         is->s.here = is->s.first;
2202         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2203         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2204                 error = xattr_check_inode(inode, header, is->s.end);
2205                 if (error)
2206                         return error;
2207                 /* Find the named attribute. */
2208                 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2209                                          i->name_index, i->name, 0);
2210                 if (error && error != -ENODATA)
2211                         return error;
2212                 is->s.not_found = error;
2213         }
2214         return 0;
2215 }
2216
2217 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_INODE_HAS_XATTR_SPACE(inode))
2226                 return -ENOSPC;
2227
2228         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2229         if (error)
2230                 return error;
2231         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2232         if (!IS_LAST_ENTRY(s->first)) {
2233                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2234                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2235         } else {
2236                 header->h_magic = cpu_to_le32(0);
2237                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2238         }
2239         return 0;
2240 }
2241
2242 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2243                                  struct ext4_xattr_info *i)
2244 {
2245         void *value;
2246
2247         /* When e_value_inum is set the value is stored externally. */
2248         if (s->here->e_value_inum)
2249                 return 0;
2250         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2251                 return 0;
2252         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2253         return !memcmp(value, i->value, i->value_len);
2254 }
2255
2256 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2257 {
2258         struct buffer_head *bh;
2259         int error;
2260
2261         if (!EXT4_I(inode)->i_file_acl)
2262                 return NULL;
2263         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2264         if (IS_ERR(bh))
2265                 return bh;
2266         error = ext4_xattr_check_block(inode, bh);
2267         if (error) {
2268                 brelse(bh);
2269                 return ERR_PTR(error);
2270         }
2271         return bh;
2272 }
2273
2274 /*
2275  * ext4_xattr_set_handle()
2276  *
2277  * Create, replace or remove an extended attribute for this inode.  Value
2278  * is NULL to remove an existing extended attribute, and non-NULL to
2279  * either replace an existing extended attribute, or create a new extended
2280  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2281  * specify that an extended attribute must exist and must not exist
2282  * previous to the call, respectively.
2283  *
2284  * Returns 0, or a negative error number on failure.
2285  */
2286 int
2287 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2288                       const char *name, const void *value, size_t value_len,
2289                       int flags)
2290 {
2291         struct ext4_xattr_info i = {
2292                 .name_index = name_index,
2293                 .name = name,
2294                 .value = value,
2295                 .value_len = value_len,
2296                 .in_inode = 0,
2297         };
2298         struct ext4_xattr_ibody_find is = {
2299                 .s = { .not_found = -ENODATA, },
2300         };
2301         struct ext4_xattr_block_find bs = {
2302                 .s = { .not_found = -ENODATA, },
2303         };
2304         int no_expand;
2305         int error;
2306
2307         if (!name)
2308                 return -EINVAL;
2309         if (strlen(name) > 255)
2310                 return -ERANGE;
2311
2312         ext4_write_lock_xattr(inode, &no_expand);
2313
2314         /* Check journal credits under write lock. */
2315         if (ext4_handle_valid(handle)) {
2316                 struct buffer_head *bh;
2317                 int credits;
2318
2319                 bh = ext4_xattr_get_block(inode);
2320                 if (IS_ERR(bh)) {
2321                         error = PTR_ERR(bh);
2322                         goto cleanup;
2323                 }
2324
2325                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2326                                                    value_len,
2327                                                    flags & XATTR_CREATE);
2328                 brelse(bh);
2329
2330                 if (jbd2_handle_buffer_credits(handle) < credits) {
2331                         error = -ENOSPC;
2332                         goto cleanup;
2333                 }
2334                 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2335         }
2336
2337         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2338         if (error)
2339                 goto cleanup;
2340
2341         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2342                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2343                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2344                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2345         }
2346
2347         error = ext4_xattr_ibody_find(inode, &i, &is);
2348         if (error)
2349                 goto cleanup;
2350         if (is.s.not_found)
2351                 error = ext4_xattr_block_find(inode, &i, &bs);
2352         if (error)
2353                 goto cleanup;
2354         if (is.s.not_found && bs.s.not_found) {
2355                 error = -ENODATA;
2356                 if (flags & XATTR_REPLACE)
2357                         goto cleanup;
2358                 error = 0;
2359                 if (!value)
2360                         goto cleanup;
2361         } else {
2362                 error = -EEXIST;
2363                 if (flags & XATTR_CREATE)
2364                         goto cleanup;
2365         }
2366
2367         if (!value) {
2368                 if (!is.s.not_found)
2369                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2370                 else if (!bs.s.not_found)
2371                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2372         } else {
2373                 error = 0;
2374                 /* Xattr value did not change? Save us some work and bail out */
2375                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2376                         goto cleanup;
2377                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2378                         goto cleanup;
2379
2380                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2381                     (EXT4_XATTR_SIZE(i.value_len) >
2382                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2383                         i.in_inode = 1;
2384 retry_inode:
2385                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2386                 if (!error && !bs.s.not_found) {
2387                         i.value = NULL;
2388                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2389                 } else if (error == -ENOSPC) {
2390                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2391                                 brelse(bs.bh);
2392                                 bs.bh = NULL;
2393                                 error = ext4_xattr_block_find(inode, &i, &bs);
2394                                 if (error)
2395                                         goto cleanup;
2396                         }
2397                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2398                         if (!error && !is.s.not_found) {
2399                                 i.value = NULL;
2400                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2401                                                              &is);
2402                         } else if (error == -ENOSPC) {
2403                                 /*
2404                                  * Xattr does not fit in the block, store at
2405                                  * external inode if possible.
2406                                  */
2407                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2408                                     i.value_len && !i.in_inode) {
2409                                         i.in_inode = 1;
2410                                         goto retry_inode;
2411                                 }
2412                         }
2413                 }
2414         }
2415         if (!error) {
2416                 ext4_xattr_update_super_block(handle, inode->i_sb);
2417                 inode->i_ctime = current_time(inode);
2418                 if (!value)
2419                         no_expand = 0;
2420                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2421                 /*
2422                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2423                  * error != 0.
2424                  */
2425                 is.iloc.bh = NULL;
2426                 if (IS_SYNC(inode))
2427                         ext4_handle_sync(handle);
2428         }
2429         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2430
2431 cleanup:
2432         brelse(is.iloc.bh);
2433         brelse(bs.bh);
2434         ext4_write_unlock_xattr(inode, &no_expand);
2435         return error;
2436 }
2437
2438 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2439                            bool is_create, int *credits)
2440 {
2441         struct buffer_head *bh;
2442         int err;
2443
2444         *credits = 0;
2445
2446         if (!EXT4_SB(inode->i_sb)->s_journal)
2447                 return 0;
2448
2449         down_read(&EXT4_I(inode)->xattr_sem);
2450
2451         bh = ext4_xattr_get_block(inode);
2452         if (IS_ERR(bh)) {
2453                 err = PTR_ERR(bh);
2454         } else {
2455                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2456                                                     value_len, is_create);
2457                 brelse(bh);
2458                 err = 0;
2459         }
2460
2461         up_read(&EXT4_I(inode)->xattr_sem);
2462         return err;
2463 }
2464
2465 /*
2466  * ext4_xattr_set()
2467  *
2468  * Like ext4_xattr_set_handle, but start from an inode. This extended
2469  * attribute modification is a filesystem transaction by itself.
2470  *
2471  * Returns 0, or a negative error number on failure.
2472  */
2473 int
2474 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2475                const void *value, size_t value_len, int flags)
2476 {
2477         handle_t *handle;
2478         struct super_block *sb = inode->i_sb;
2479         int error, retries = 0;
2480         int credits;
2481
2482         error = dquot_initialize(inode);
2483         if (error)
2484                 return error;
2485
2486 retry:
2487         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2488                                        &credits);
2489         if (error)
2490                 return error;
2491
2492         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2493         if (IS_ERR(handle)) {
2494                 error = PTR_ERR(handle);
2495         } else {
2496                 int error2;
2497
2498                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2499                                               value, value_len, flags);
2500                 error2 = ext4_journal_stop(handle);
2501                 if (error == -ENOSPC &&
2502                     ext4_should_retry_alloc(sb, &retries))
2503                         goto retry;
2504                 if (error == 0)
2505                         error = error2;
2506         }
2507         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2508
2509         return error;
2510 }
2511
2512 /*
2513  * Shift the EA entries in the inode to create space for the increased
2514  * i_extra_isize.
2515  */
2516 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2517                                      int value_offs_shift, void *to,
2518                                      void *from, size_t n)
2519 {
2520         struct ext4_xattr_entry *last = entry;
2521         int new_offs;
2522
2523         /* We always shift xattr headers further thus offsets get lower */
2524         BUG_ON(value_offs_shift > 0);
2525
2526         /* Adjust the value offsets of the entries */
2527         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2528                 if (!last->e_value_inum && last->e_value_size) {
2529                         new_offs = le16_to_cpu(last->e_value_offs) +
2530                                                         value_offs_shift;
2531                         last->e_value_offs = cpu_to_le16(new_offs);
2532                 }
2533         }
2534         /* Shift the entries by n bytes */
2535         memmove(to, from, n);
2536 }
2537
2538 /*
2539  * Move xattr pointed to by 'entry' from inode into external xattr block
2540  */
2541 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2542                                     struct ext4_inode *raw_inode,
2543                                     struct ext4_xattr_entry *entry)
2544 {
2545         struct ext4_xattr_ibody_find *is = NULL;
2546         struct ext4_xattr_block_find *bs = NULL;
2547         char *buffer = NULL, *b_entry_name = NULL;
2548         size_t value_size = le32_to_cpu(entry->e_value_size);
2549         struct ext4_xattr_info i = {
2550                 .value = NULL,
2551                 .value_len = 0,
2552                 .name_index = entry->e_name_index,
2553                 .in_inode = !!entry->e_value_inum,
2554         };
2555         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2556         int needs_kvfree = 0;
2557         int error;
2558
2559         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2560         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2561         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2562         if (!is || !bs || !b_entry_name) {
2563                 error = -ENOMEM;
2564                 goto out;
2565         }
2566
2567         is->s.not_found = -ENODATA;
2568         bs->s.not_found = -ENODATA;
2569         is->iloc.bh = NULL;
2570         bs->bh = NULL;
2571
2572         /* Save the entry name and the entry value */
2573         if (entry->e_value_inum) {
2574                 buffer = kvmalloc(value_size, GFP_NOFS);
2575                 if (!buffer) {
2576                         error = -ENOMEM;
2577                         goto out;
2578                 }
2579                 needs_kvfree = 1;
2580                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2581                 if (error)
2582                         goto out;
2583         } else {
2584                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2585                 buffer = (void *)IFIRST(header) + value_offs;
2586         }
2587
2588         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2589         b_entry_name[entry->e_name_len] = '\0';
2590         i.name = b_entry_name;
2591
2592         error = ext4_get_inode_loc(inode, &is->iloc);
2593         if (error)
2594                 goto out;
2595
2596         error = ext4_xattr_ibody_find(inode, &i, is);
2597         if (error)
2598                 goto out;
2599
2600         i.value = buffer;
2601         i.value_len = value_size;
2602         error = ext4_xattr_block_find(inode, &i, bs);
2603         if (error)
2604                 goto out;
2605
2606         /* Move ea entry from the inode into the block */
2607         error = ext4_xattr_block_set(handle, inode, &i, bs);
2608         if (error)
2609                 goto out;
2610
2611         /* Remove the chosen entry from the inode */
2612         i.value = NULL;
2613         i.value_len = 0;
2614         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2615
2616 out:
2617         kfree(b_entry_name);
2618         if (needs_kvfree && buffer)
2619                 kvfree(buffer);
2620         if (is)
2621                 brelse(is->iloc.bh);
2622         if (bs)
2623                 brelse(bs->bh);
2624         kfree(is);
2625         kfree(bs);
2626
2627         return error;
2628 }
2629
2630 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2631                                        struct ext4_inode *raw_inode,
2632                                        int isize_diff, size_t ifree,
2633                                        size_t bfree, int *total_ino)
2634 {
2635         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2636         struct ext4_xattr_entry *small_entry;
2637         struct ext4_xattr_entry *entry;
2638         struct ext4_xattr_entry *last;
2639         unsigned int entry_size;        /* EA entry size */
2640         unsigned int total_size;        /* EA entry size + value size */
2641         unsigned int min_total_size;
2642         int error;
2643
2644         while (isize_diff > ifree) {
2645                 entry = NULL;
2646                 small_entry = NULL;
2647                 min_total_size = ~0U;
2648                 last = IFIRST(header);
2649                 /* Find the entry best suited to be pushed into EA block */
2650                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2651                         /* never move system.data out of the inode */
2652                         if ((last->e_name_len == 4) &&
2653                             (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2654                             !memcmp(last->e_name, "data", 4))
2655                                 continue;
2656                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2657                         if (!last->e_value_inum)
2658                                 total_size += EXT4_XATTR_SIZE(
2659                                                le32_to_cpu(last->e_value_size));
2660                         if (total_size <= bfree &&
2661                             total_size < min_total_size) {
2662                                 if (total_size + ifree < isize_diff) {
2663                                         small_entry = last;
2664                                 } else {
2665                                         entry = last;
2666                                         min_total_size = total_size;
2667                                 }
2668                         }
2669                 }
2670
2671                 if (entry == NULL) {
2672                         if (small_entry == NULL)
2673                                 return -ENOSPC;
2674                         entry = small_entry;
2675                 }
2676
2677                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2678                 total_size = entry_size;
2679                 if (!entry->e_value_inum)
2680                         total_size += EXT4_XATTR_SIZE(
2681                                               le32_to_cpu(entry->e_value_size));
2682                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2683                                                  entry);
2684                 if (error)
2685                         return error;
2686
2687                 *total_ino -= entry_size;
2688                 ifree += total_size;
2689                 bfree -= total_size;
2690         }
2691
2692         return 0;
2693 }
2694
2695 /*
2696  * Expand an inode by new_extra_isize bytes when EAs are present.
2697  * Returns 0 on success or negative error number on failure.
2698  */
2699 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2700                                struct ext4_inode *raw_inode, handle_t *handle)
2701 {
2702         struct ext4_xattr_ibody_header *header;
2703         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2704         static unsigned int mnt_count;
2705         size_t min_offs;
2706         size_t ifree, bfree;
2707         int total_ino;
2708         void *base, *end;
2709         int error = 0, tried_min_extra_isize = 0;
2710         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2711         int isize_diff; /* How much do we need to grow i_extra_isize */
2712
2713 retry:
2714         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2715         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2716                 return 0;
2717
2718         header = IHDR(inode, raw_inode);
2719
2720         /*
2721          * Check if enough free space is available in the inode to shift the
2722          * entries ahead by new_extra_isize.
2723          */
2724
2725         base = IFIRST(header);
2726         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2727         min_offs = end - base;
2728         total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2729
2730         error = xattr_check_inode(inode, header, end);
2731         if (error)
2732                 goto cleanup;
2733
2734         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2735         if (ifree >= isize_diff)
2736                 goto shift;
2737
2738         /*
2739          * Enough free space isn't available in the inode, check if
2740          * EA block can hold new_extra_isize bytes.
2741          */
2742         if (EXT4_I(inode)->i_file_acl) {
2743                 struct buffer_head *bh;
2744
2745                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2746                 if (IS_ERR(bh)) {
2747                         error = PTR_ERR(bh);
2748                         goto cleanup;
2749                 }
2750                 error = ext4_xattr_check_block(inode, bh);
2751                 if (error) {
2752                         brelse(bh);
2753                         goto cleanup;
2754                 }
2755                 base = BHDR(bh);
2756                 end = bh->b_data + bh->b_size;
2757                 min_offs = end - base;
2758                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2759                                               NULL);
2760                 brelse(bh);
2761                 if (bfree + ifree < isize_diff) {
2762                         if (!tried_min_extra_isize && s_min_extra_isize) {
2763                                 tried_min_extra_isize++;
2764                                 new_extra_isize = s_min_extra_isize;
2765                                 goto retry;
2766                         }
2767                         error = -ENOSPC;
2768                         goto cleanup;
2769                 }
2770         } else {
2771                 bfree = inode->i_sb->s_blocksize;
2772         }
2773
2774         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2775                                             isize_diff, ifree, bfree,
2776                                             &total_ino);
2777         if (error) {
2778                 if (error == -ENOSPC && !tried_min_extra_isize &&
2779                     s_min_extra_isize) {
2780                         tried_min_extra_isize++;
2781                         new_extra_isize = s_min_extra_isize;
2782                         goto retry;
2783                 }
2784                 goto cleanup;
2785         }
2786 shift:
2787         /* Adjust the offsets and shift the remaining entries ahead */
2788         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2789                         - new_extra_isize, (void *)raw_inode +
2790                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2791                         (void *)header, total_ino);
2792         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2793
2794         if (ext4_has_inline_data(inode))
2795                 error = ext4_find_inline_data_nolock(inode);
2796
2797 cleanup:
2798         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2799                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2800                              inode->i_ino);
2801                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2802         }
2803         return error;
2804 }
2805
2806 #define EIA_INCR 16 /* must be 2^n */
2807 #define EIA_MASK (EIA_INCR - 1)
2808
2809 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2810  * If @ea_inode_array is new or full it will be grown and the old
2811  * contents copied over.
2812  */
2813 static int
2814 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2815                         struct inode *inode)
2816 {
2817         if (*ea_inode_array == NULL) {
2818                 /*
2819                  * Start with 15 inodes, so it fits into a power-of-two size.
2820                  * If *ea_inode_array is NULL, this is essentially offsetof()
2821                  */
2822                 (*ea_inode_array) =
2823                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2824                                          inodes[EIA_MASK]),
2825                                 GFP_NOFS);
2826                 if (*ea_inode_array == NULL)
2827                         return -ENOMEM;
2828                 (*ea_inode_array)->count = 0;
2829         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2830                 /* expand the array once all 15 + n * 16 slots are full */
2831                 struct ext4_xattr_inode_array *new_array = NULL;
2832                 int count = (*ea_inode_array)->count;
2833
2834                 /* if new_array is NULL, this is essentially offsetof() */
2835                 new_array = kmalloc(
2836                                 offsetof(struct ext4_xattr_inode_array,
2837                                          inodes[count + EIA_INCR]),
2838                                 GFP_NOFS);
2839                 if (new_array == NULL)
2840                         return -ENOMEM;
2841                 memcpy(new_array, *ea_inode_array,
2842                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2843                 kfree(*ea_inode_array);
2844                 *ea_inode_array = new_array;
2845         }
2846         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2847         return 0;
2848 }
2849
2850 /*
2851  * ext4_xattr_delete_inode()
2852  *
2853  * Free extended attribute resources associated with this inode. Traverse
2854  * all entries and decrement reference on any xattr inodes associated with this
2855  * inode. This is called immediately before an inode is freed. We have exclusive
2856  * access to the inode. If an orphan inode is deleted it will also release its
2857  * references on xattr block and xattr inodes.
2858  */
2859 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2860                             struct ext4_xattr_inode_array **ea_inode_array,
2861                             int extra_credits)
2862 {
2863         struct buffer_head *bh = NULL;
2864         struct ext4_xattr_ibody_header *header;
2865         struct ext4_iloc iloc = { .bh = NULL };
2866         struct ext4_xattr_entry *entry;
2867         struct inode *ea_inode;
2868         int error;
2869
2870         error = ext4_journal_ensure_credits(handle, extra_credits,
2871                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2872         if (error < 0) {
2873                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2874                 goto cleanup;
2875         }
2876
2877         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2878             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2879
2880                 error = ext4_get_inode_loc(inode, &iloc);
2881                 if (error) {
2882                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2883                         goto cleanup;
2884                 }
2885
2886                 error = ext4_journal_get_write_access(handle, iloc.bh);
2887                 if (error) {
2888                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2889                                          error);
2890                         goto cleanup;
2891                 }
2892
2893                 header = IHDR(inode, ext4_raw_inode(&iloc));
2894                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2895                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2896                                                      IFIRST(header),
2897                                                      false /* block_csum */,
2898                                                      ea_inode_array,
2899                                                      extra_credits,
2900                                                      false /* skip_quota */);
2901         }
2902
2903         if (EXT4_I(inode)->i_file_acl) {
2904                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2905                 if (IS_ERR(bh)) {
2906                         error = PTR_ERR(bh);
2907                         if (error == -EIO) {
2908                                 EXT4_ERROR_INODE_ERR(inode, EIO,
2909                                                      "block %llu read error",
2910                                                      EXT4_I(inode)->i_file_acl);
2911                         }
2912                         bh = NULL;
2913                         goto cleanup;
2914                 }
2915                 error = ext4_xattr_check_block(inode, bh);
2916                 if (error)
2917                         goto cleanup;
2918
2919                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2920                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2921                              entry = EXT4_XATTR_NEXT(entry)) {
2922                                 if (!entry->e_value_inum)
2923                                         continue;
2924                                 error = ext4_xattr_inode_iget(inode,
2925                                               le32_to_cpu(entry->e_value_inum),
2926                                               le32_to_cpu(entry->e_hash),
2927                                               &ea_inode);
2928                                 if (error)
2929                                         continue;
2930                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2931                                               le32_to_cpu(entry->e_value_size));
2932                                 iput(ea_inode);
2933                         }
2934
2935                 }
2936
2937                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2938                                          extra_credits);
2939                 /*
2940                  * Update i_file_acl value in the same transaction that releases
2941                  * block.
2942                  */
2943                 EXT4_I(inode)->i_file_acl = 0;
2944                 error = ext4_mark_inode_dirty(handle, inode);
2945                 if (error) {
2946                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2947                                          error);
2948                         goto cleanup;
2949                 }
2950                 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2951         }
2952         error = 0;
2953 cleanup:
2954         brelse(iloc.bh);
2955         brelse(bh);
2956         return error;
2957 }
2958
2959 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2960 {
2961         int idx;
2962
2963         if (ea_inode_array == NULL)
2964                 return;
2965
2966         for (idx = 0; idx < ea_inode_array->count; ++idx)
2967                 iput(ea_inode_array->inodes[idx]);
2968         kfree(ea_inode_array);
2969 }
2970
2971 /*
2972  * ext4_xattr_block_cache_insert()
2973  *
2974  * Create a new entry in the extended attribute block cache, and insert
2975  * it unless such an entry is already in the cache.
2976  *
2977  * Returns 0, or a negative error number on failure.
2978  */
2979 static void
2980 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2981                               struct buffer_head *bh)
2982 {
2983         struct ext4_xattr_header *header = BHDR(bh);
2984         __u32 hash = le32_to_cpu(header->h_hash);
2985         int reusable = le32_to_cpu(header->h_refcount) <
2986                        EXT4_XATTR_REFCOUNT_MAX;
2987         int error;
2988
2989         if (!ea_block_cache)
2990                 return;
2991         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2992                                       bh->b_blocknr, reusable);
2993         if (error) {
2994                 if (error == -EBUSY)
2995                         ea_bdebug(bh, "already in cache");
2996         } else
2997                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2998 }
2999
3000 /*
3001  * ext4_xattr_cmp()
3002  *
3003  * Compare two extended attribute blocks for equality.
3004  *
3005  * Returns 0 if the blocks are equal, 1 if they differ, and
3006  * a negative error number on errors.
3007  */
3008 static int
3009 ext4_xattr_cmp(struct ext4_xattr_header *header1,
3010                struct ext4_xattr_header *header2)
3011 {
3012         struct ext4_xattr_entry *entry1, *entry2;
3013
3014         entry1 = ENTRY(header1+1);
3015         entry2 = ENTRY(header2+1);
3016         while (!IS_LAST_ENTRY(entry1)) {
3017                 if (IS_LAST_ENTRY(entry2))
3018                         return 1;
3019                 if (entry1->e_hash != entry2->e_hash ||
3020                     entry1->e_name_index != entry2->e_name_index ||
3021                     entry1->e_name_len != entry2->e_name_len ||
3022                     entry1->e_value_size != entry2->e_value_size ||
3023                     entry1->e_value_inum != entry2->e_value_inum ||
3024                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3025                         return 1;
3026                 if (!entry1->e_value_inum &&
3027                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3028                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3029                            le32_to_cpu(entry1->e_value_size)))
3030                         return 1;
3031
3032                 entry1 = EXT4_XATTR_NEXT(entry1);
3033                 entry2 = EXT4_XATTR_NEXT(entry2);
3034         }
3035         if (!IS_LAST_ENTRY(entry2))
3036                 return 1;
3037         return 0;
3038 }
3039
3040 /*
3041  * ext4_xattr_block_cache_find()
3042  *
3043  * Find an identical extended attribute block.
3044  *
3045  * Returns a pointer to the block found, or NULL if such a block was
3046  * not found or an error occurred.
3047  */
3048 static struct buffer_head *
3049 ext4_xattr_block_cache_find(struct inode *inode,
3050                             struct ext4_xattr_header *header,
3051                             struct mb_cache_entry **pce)
3052 {
3053         __u32 hash = le32_to_cpu(header->h_hash);
3054         struct mb_cache_entry *ce;
3055         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3056
3057         if (!ea_block_cache)
3058                 return NULL;
3059         if (!header->h_hash)
3060                 return NULL;  /* never share */
3061         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3062         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3063         while (ce) {
3064                 struct buffer_head *bh;
3065
3066                 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3067                 if (IS_ERR(bh)) {
3068                         if (PTR_ERR(bh) == -ENOMEM)
3069                                 return NULL;
3070                         bh = NULL;
3071                         EXT4_ERROR_INODE(inode, "block %lu read error",
3072                                          (unsigned long)ce->e_value);
3073                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3074                         *pce = ce;
3075                         return bh;
3076                 }
3077                 brelse(bh);
3078                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3079         }
3080         return NULL;
3081 }
3082
3083 #define NAME_HASH_SHIFT 5
3084 #define VALUE_HASH_SHIFT 16
3085
3086 /*
3087  * ext4_xattr_hash_entry()
3088  *
3089  * Compute the hash of an extended attribute.
3090  */
3091 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3092                                     size_t value_count)
3093 {
3094         __u32 hash = 0;
3095
3096         while (name_len--) {
3097                 hash = (hash << NAME_HASH_SHIFT) ^
3098                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3099                        *name++;
3100         }
3101         while (value_count--) {
3102                 hash = (hash << VALUE_HASH_SHIFT) ^
3103                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3104                        le32_to_cpu(*value++);
3105         }
3106         return cpu_to_le32(hash);
3107 }
3108
3109 #undef NAME_HASH_SHIFT
3110 #undef VALUE_HASH_SHIFT
3111
3112 #define BLOCK_HASH_SHIFT 16
3113
3114 /*
3115  * ext4_xattr_rehash()
3116  *
3117  * Re-compute the extended attribute hash value after an entry has changed.
3118  */
3119 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3120 {
3121         struct ext4_xattr_entry *here;
3122         __u32 hash = 0;
3123
3124         here = ENTRY(header+1);
3125         while (!IS_LAST_ENTRY(here)) {
3126                 if (!here->e_hash) {
3127                         /* Block is not shared if an entry's hash value == 0 */
3128                         hash = 0;
3129                         break;
3130                 }
3131                 hash = (hash << BLOCK_HASH_SHIFT) ^
3132                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3133                        le32_to_cpu(here->e_hash);
3134                 here = EXT4_XATTR_NEXT(here);
3135         }
3136         header->h_hash = cpu_to_le32(hash);
3137 }
3138
3139 #undef BLOCK_HASH_SHIFT
3140
3141 #define HASH_BUCKET_BITS        10
3142
3143 struct mb_cache *
3144 ext4_xattr_create_cache(void)
3145 {
3146         return mb_cache_create(HASH_BUCKET_BITS);
3147 }
3148
3149 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3150 {
3151         if (cache)
3152                 mb_cache_destroy(cache);
3153 }
3154