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, <[email protected]>
   6  *
   7  * Fix by Harrison Xing <[email protected]>.
   8  * Ext4 code with a lot of help from Eric Jarman <[email protected]>.
   9  * Extended attributes for symlinks and special files added per
  10  *  suggestion of Luka Renko <[email protected]>.
  11  * xattr consolidation Copyright (c) 2004 James Morris <[email protected]>,
  12  *  Red Hat Inc.
  13  * ea-in-inode support by Alex Tomas <[email protected]> aka bzzz
  14  *  and Andreas Gruenbacher <[email protected]>.
  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 __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value,
  85                                     size_t value_count);
  86 static void ext4_xattr_rehash(struct ext4_xattr_header *);
  87
  88 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
  89         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  90 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  91         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &nop_posix_acl_access,
  92         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &nop_posix_acl_default,
  93 #endif
  94         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
  95 #ifdef CONFIG_EXT4_FS_SECURITY
  96         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
  97 #endif
  98         [EXT4_XATTR_INDEX_HURD]              = &ext4_xattr_hurd_handler,
  99 };
 100
 101 const struct xattr_handler * const ext4_xattr_handlers[] = {
 102         &ext4_xattr_user_handler,
 103         &ext4_xattr_trusted_handler,
 104 #ifdef CONFIG_EXT4_FS_SECURITY
 105         &ext4_xattr_security_handler,
 106 #endif
 107         &ext4_xattr_hurd_handler,
 108         NULL
 109 };
 110
 111 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 112                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 113
 114 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 115                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 116
 117 static int
 118 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 119                         struct inode *inode);
 120
 121 #ifdef CONFIG_LOCKDEP
 122 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 123 {
 124         struct ext4_inode_info *ei = EXT4_I(ea_inode);
 125
 126         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 127         (void) ei;      /* shut up clang warning if !CONFIG_LOCKDEP */
 128         lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
 129 }
 130 #endif
 131
 132 static __le32 ext4_xattr_block_csum(struct inode *inode,
 133                                     sector_t block_nr,
 134                                     struct ext4_xattr_header *hdr)
 135 {
 136         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 137         __u32 csum;
 138         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 139         __u32 dummy_csum = 0;
 140         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 141
 142         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 143                            sizeof(dsk_block_nr));
 144         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 145         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 146         offset += sizeof(dummy_csum);
 147         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 148                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 149
 150         return cpu_to_le32(csum);
 151 }
 152
 153 static int ext4_xattr_block_csum_verify(struct inode *inode,
 154                                         struct buffer_head *bh)
 155 {
 156         struct ext4_xattr_header *hdr = BHDR(bh);
 157         int ret = 1;
 158
 159         if (ext4_has_metadata_csum(inode->i_sb)) {
 160                 lock_buffer(bh);
 161                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 162                                                         bh->b_blocknr, hdr));
 163                 unlock_buffer(bh);
 164         }
 165         return ret;
 166 }
 167
 168 static void ext4_xattr_block_csum_set(struct inode *inode,
 169                                       struct buffer_head *bh)
 170 {
 171         if (ext4_has_metadata_csum(inode->i_sb))
 172                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 173                                                 bh->b_blocknr, BHDR(bh));
 174 }
 175
 176 static inline const char *ext4_xattr_prefix(int name_index,
 177                                             struct dentry *dentry)
 178 {
 179         const struct xattr_handler *handler = NULL;
 180
 181         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 182                 handler = ext4_xattr_handler_map[name_index];
 183
 184         if (!xattr_handler_can_list(handler, dentry))
 185                 return NULL;
 186
 187         return xattr_prefix(handler);
 188 }
 189
 190 static int
 191 check_xattrs(struct inode *inode, struct buffer_head *bh,
 192              struct ext4_xattr_entry *entry, void *end, void *value_start,
 193              const char *function, unsigned int line)
 194 {
 195         struct ext4_xattr_entry *e = entry;
 196         int err = -EFSCORRUPTED;
 197         char *err_str;
 198
 199         if (bh) {
 200                 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 201                     BHDR(bh)->h_blocks != cpu_to_le32(1)) {
 202                         err_str = "invalid header";
 203                         goto errout;
 204                 }
 205                 if (buffer_verified(bh))
 206                         return 0;
 207                 if (!ext4_xattr_block_csum_verify(inode, bh)) {
 208                         err = -EFSBADCRC;
 209                         err_str = "invalid checksum";
 210                         goto errout;
 211                 }
 212         } else {
 213                 struct ext4_xattr_ibody_header *header = value_start;
 214
 215                 header -= 1;
 216                 if (end - (void *)header < sizeof(*header) + sizeof(u32)) {
 217                         err_str = "in-inode xattr block too small";
 218                         goto errout;
 219                 }
 220                 if (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
 221                         err_str = "bad magic number in in-inode xattr";
 222                         goto errout;
 223                 }
 224         }
 225
 226         /* Find the end of the names list */
 227         while (!IS_LAST_ENTRY(e)) {
 228                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 229                 if ((void *)next >= end) {
 230                         err_str = "e_name out of bounds";
 231                         goto errout;
 232                 }
 233                 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len) {
 234                         err_str = "bad e_name length";
 235                         goto errout;
 236                 }
 237                 e = next;
 238         }
 239
 240         /* Check the values */
 241         while (!IS_LAST_ENTRY(entry)) {
 242                 u32 size = le32_to_cpu(entry->e_value_size);
 243                 unsigned long ea_ino = le32_to_cpu(entry->e_value_inum);
 244
 245                 if (!ext4_has_feature_ea_inode(inode->i_sb) && ea_ino) {
 246                         err_str = "ea_inode specified without ea_inode feature enabled";
 247                         goto errout;
 248                 }
 249                 if (ea_ino && ((ea_ino == EXT4_ROOT_INO) ||
 250                                !ext4_valid_inum(inode->i_sb, ea_ino))) {
 251                         err_str = "invalid ea_ino";
 252                         goto errout;
 253                 }
 254                 if (size > EXT4_XATTR_SIZE_MAX) {
 255                         err_str = "e_value size too large";
 256                         goto errout;
 257                 }
 258
 259                 if (size != 0 && entry->e_value_inum == 0) {
 260                         u16 offs = le16_to_cpu(entry->e_value_offs);
 261                         void *value;
 262
 263                         /*
 264                          * The value cannot overlap the names, and the value
 265                          * with padding cannot extend beyond 'end'.  Check both
 266                          * the padded and unpadded sizes, since the size may
 267                          * overflow to 0 when adding padding.
 268                          */
 269                         if (offs > end - value_start) {
 270                                 err_str = "e_value out of bounds";
 271                                 goto errout;
 272                         }
 273                         value = value_start + offs;
 274                         if (value < (void *)e + sizeof(u32) ||
 275                             size > end - value ||
 276                             EXT4_XATTR_SIZE(size) > end - value) {
 277                                 err_str = "overlapping e_value ";
 278                                 goto errout;
 279                         }
 280                 }
 281                 entry = EXT4_XATTR_NEXT(entry);
 282         }
 283         if (bh)
 284                 set_buffer_verified(bh);
 285         return 0;
 286
 287 errout:
 288         if (bh)
 289                 __ext4_error_inode(inode, function, line, 0, -err,
 290                                    "corrupted xattr block %llu: %s",
 291                                    (unsigned long long) bh->b_blocknr,
 292                                    err_str);
 293         else
 294                 __ext4_error_inode(inode, function, line, 0, -err,
 295                                    "corrupted in-inode xattr: %s", err_str);
 296         return err;
 297 }
 298
 299 static inline int
 300 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
 301                          const char *function, unsigned int line)
 302 {
 303         return check_xattrs(inode, bh, BFIRST(bh), bh->b_data + bh->b_size,
 304                             bh->b_data, function, line);
 305 }
 306
 307 #define ext4_xattr_check_block(inode, bh) \
 308         __ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
 309
 310
 311 static inline int
 312 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 313                          void *end, const char *function, unsigned int line)
 314 {
 315         return check_xattrs(inode, NULL, IFIRST(header), end, IFIRST(header),
 316                             function, line);
 317 }
 318
 319 #define xattr_check_inode(inode, header, end) \
 320         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 321
 322 static int
 323 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
 324                  void *end, int name_index, const char *name, int sorted)
 325 {
 326         struct ext4_xattr_entry *entry, *next;
 327         size_t name_len;
 328         int cmp = 1;
 329
 330         if (name == NULL)
 331                 return -EINVAL;
 332         name_len = strlen(name);
 333         for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
 334                 next = EXT4_XATTR_NEXT(entry);
 335                 if ((void *) next >= end) {
 336                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
 337                         return -EFSCORRUPTED;
 338                 }
 339                 cmp = name_index - entry->e_name_index;
 340                 if (!cmp)
 341                         cmp = name_len - entry->e_name_len;
 342                 if (!cmp)
 343                         cmp = memcmp(name, entry->e_name, name_len);
 344                 if (cmp <= 0 && (sorted || cmp == 0))
 345                         break;
 346         }
 347         *pentry = entry;
 348         return cmp ? -ENODATA : 0;
 349 }
 350
 351 static u32
 352 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 353 {
 354         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 355 }
 356
 357 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 358 {
 359         return ((u64) inode_get_ctime_sec(ea_inode) << 32) |
 360                 (u32) inode_peek_iversion_raw(ea_inode);
 361 }
 362
 363 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 364 {
 365         inode_set_ctime(ea_inode, (u32)(ref_count >> 32), 0);
 366         inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
 367 }
 368
 369 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 370 {
 371         return (u32) inode_get_atime_sec(ea_inode);
 372 }
 373
 374 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 375 {
 376         inode_set_atime(ea_inode, hash, 0);
 377 }
 378
 379 /*
 380  * Read the EA value from an inode.
 381  */
 382 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 383 {
 384         int blocksize = 1 << ea_inode->i_blkbits;
 385         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 386         int tail_size = (size % blocksize) ?: blocksize;
 387         struct buffer_head *bhs_inline[8];
 388         struct buffer_head **bhs = bhs_inline;
 389         int i, ret;
 390
 391         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 392                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 393                 if (!bhs)
 394                         return -ENOMEM;
 395         }
 396
 397         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 398                                true /* wait */, bhs);
 399         if (ret)
 400                 goto free_bhs;
 401
 402         for (i = 0; i < bh_count; i++) {
 403                 /* There shouldn't be any holes in ea_inode. */
 404                 if (!bhs[i]) {
 405                         ret = -EFSCORRUPTED;
 406                         goto put_bhs;
 407                 }
 408                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 409                        i < bh_count - 1 ? blocksize : tail_size);
 410         }
 411         ret = 0;
 412 put_bhs:
 413         for (i = 0; i < bh_count; i++)
 414                 brelse(bhs[i]);
 415 free_bhs:
 416         if (bhs != bhs_inline)
 417                 kfree(bhs);
 418         return ret;
 419 }
 420
 421 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode_get_mtime_sec(inode)))
 422
 423 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 424                                  u32 ea_inode_hash, struct inode **ea_inode)
 425 {
 426         struct inode *inode;
 427         int err;
 428
 429         /*
 430          * We have to check for this corruption early as otherwise
 431          * iget_locked() could wait indefinitely for the state of our
 432          * parent inode.
 433          */
 434         if (parent->i_ino == ea_ino) {
 435                 ext4_error(parent->i_sb,
 436                            "Parent and EA inode have the same ino %lu", ea_ino);
 437                 return -EFSCORRUPTED;
 438         }
 439
 440         inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
 441         if (IS_ERR(inode)) {
 442                 err = PTR_ERR(inode);
 443                 ext4_error(parent->i_sb,
 444                            "error while reading EA inode %lu err=%d", ea_ino,
 445                            err);
 446                 return err;
 447         }
 448         ext4_xattr_inode_set_class(inode);
 449
 450         /*
 451          * Check whether this is an old Lustre-style xattr inode. Lustre
 452          * implementation does not have hash validation, rather it has a
 453          * backpointer from ea_inode to the parent inode.
 454          */
 455         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 456             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 457             inode->i_generation == parent->i_generation) {
 458                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 459                 ext4_xattr_inode_set_ref(inode, 1);
 460         } else {
 461                 inode_lock(inode);
 462                 inode->i_flags |= S_NOQUOTA;
 463                 inode_unlock(inode);
 464         }
 465
 466         *ea_inode = inode;
 467         return 0;
 468 }
 469
 470 /* Remove entry from mbcache when EA inode is getting evicted */
 471 void ext4_evict_ea_inode(struct inode *inode)
 472 {
 473         struct mb_cache_entry *oe;
 474
 475         if (!EA_INODE_CACHE(inode))
 476                 return;
 477         /* Wait for entry to get unused so that we can remove it */
 478         while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
 479                         ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
 480                 mb_cache_entry_wait_unused(oe);
 481                 mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
 482         }
 483 }
 484
 485 static int
 486 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 487                                struct ext4_xattr_entry *entry, void *buffer,
 488                                size_t size)
 489 {
 490         u32 hash;
 491
 492         /* Verify stored hash matches calculated hash. */
 493         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 494         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 495                 return -EFSCORRUPTED;
 496
 497         if (entry) {
 498                 __le32 e_hash, tmp_data;
 499
 500                 /* Verify entry hash. */
 501                 tmp_data = cpu_to_le32(hash);
 502                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 503                                                &tmp_data, 1);
 504                 /* All good? */
 505                 if (e_hash == entry->e_hash)
 506                         return 0;
 507
 508                 /*
 509                  * Not good. Maybe the entry hash was calculated
 510                  * using the buggy signed char version?
 511                  */
 512                 e_hash = ext4_xattr_hash_entry_signed(entry->e_name, entry->e_name_len,
 513                                                         &tmp_data, 1);
 514                 /* Still no match - bad */
 515                 if (e_hash != entry->e_hash)
 516                         return -EFSCORRUPTED;
 517
 518                 /* Let people know about old hash */
 519                 pr_warn_once("ext4: filesystem with signed xattr name hash");
 520         }
 521         return 0;
 522 }
 523
 524 /*
 525  * Read xattr value from the EA inode.
 526  */
 527 static int
 528 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 529                      void *buffer, size_t size)
 530 {
 531         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 532         struct inode *ea_inode;
 533         int err;
 534
 535         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 536                                     le32_to_cpu(entry->e_hash), &ea_inode);
 537         if (err) {
 538                 ea_inode = NULL;
 539                 goto out;
 540         }
 541
 542         if (i_size_read(ea_inode) != size) {
 543                 ext4_warning_inode(ea_inode,
 544                                    "ea_inode file size=%llu entry size=%zu",
 545                                    i_size_read(ea_inode), size);
 546                 err = -EFSCORRUPTED;
 547                 goto out;
 548         }
 549
 550         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 551         if (err)
 552                 goto out;
 553
 554         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 555                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 556                                                      size);
 557                 if (err) {
 558                         ext4_warning_inode(ea_inode,
 559                                            "EA inode hash validation failed");
 560                         goto out;
 561                 }
 562
 563                 if (ea_inode_cache)
 564                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 565                                         ext4_xattr_inode_get_hash(ea_inode),
 566                                         ea_inode->i_ino, true /* reusable */);
 567         }
 568 out:
 569         iput(ea_inode);
 570         return err;
 571 }
 572
 573 static int
 574 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 575                      void *buffer, size_t buffer_size)
 576 {
 577         struct buffer_head *bh = NULL;
 578         struct ext4_xattr_entry *entry;
 579         size_t size;
 580         void *end;
 581         int error;
 582         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 583
 584         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 585                   name_index, name, buffer, (long)buffer_size);
 586
 587         if (!EXT4_I(inode)->i_file_acl)
 588                 return -ENODATA;
 589         ea_idebug(inode, "reading block %llu",
 590                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 591         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 592         if (IS_ERR(bh))
 593                 return PTR_ERR(bh);
 594         ea_bdebug(bh, "b_count=%d, refcount=%d",
 595                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 596         error = ext4_xattr_check_block(inode, bh);
 597         if (error)
 598                 goto cleanup;
 599         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 600         entry = BFIRST(bh);
 601         end = bh->b_data + bh->b_size;
 602         error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
 603         if (error)
 604                 goto cleanup;
 605         size = le32_to_cpu(entry->e_value_size);
 606         error = -ERANGE;
 607         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 608                 goto cleanup;
 609         if (buffer) {
 610                 if (size > buffer_size)
 611                         goto cleanup;
 612                 if (entry->e_value_inum) {
 613                         error = ext4_xattr_inode_get(inode, entry, buffer,
 614                                                      size);
 615                         if (error)
 616                                 goto cleanup;
 617                 } else {
 618                         u16 offset = le16_to_cpu(entry->e_value_offs);
 619                         void *p = bh->b_data + offset;
 620
 621                         if (unlikely(p + size > end))
 622                                 goto cleanup;
 623                         memcpy(buffer, p, size);
 624                 }
 625         }
 626         error = size;
 627
 628 cleanup:
 629         brelse(bh);
 630         return error;
 631 }
 632
 633 int
 634 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 635                      void *buffer, size_t buffer_size)
 636 {
 637         struct ext4_xattr_ibody_header *header;
 638         struct ext4_xattr_entry *entry;
 639         struct ext4_inode *raw_inode;
 640         struct ext4_iloc iloc;
 641         size_t size;
 642         void *end;
 643         int error;
 644
 645         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 646                 return -ENODATA;
 647         error = ext4_get_inode_loc(inode, &iloc);
 648         if (error)
 649                 return error;
 650         raw_inode = ext4_raw_inode(&iloc);
 651         header = IHDR(inode, raw_inode);
 652         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 653         error = xattr_check_inode(inode, header, end);
 654         if (error)
 655                 goto cleanup;
 656         entry = IFIRST(header);
 657         error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
 658         if (error)
 659                 goto cleanup;
 660         size = le32_to_cpu(entry->e_value_size);
 661         error = -ERANGE;
 662         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 663                 goto cleanup;
 664         if (buffer) {
 665                 if (size > buffer_size)
 666                         goto cleanup;
 667                 if (entry->e_value_inum) {
 668                         error = ext4_xattr_inode_get(inode, entry, buffer,
 669                                                      size);
 670                         if (error)
 671                                 goto cleanup;
 672                 } else {
 673                         u16 offset = le16_to_cpu(entry->e_value_offs);
 674                         void *p = (void *)IFIRST(header) + offset;
 675
 676                         if (unlikely(p + size > end))
 677                                 goto cleanup;
 678                         memcpy(buffer, p, size);
 679                 }
 680         }
 681         error = size;
 682
 683 cleanup:
 684         brelse(iloc.bh);
 685         return error;
 686 }
 687
 688 /*
 689  * ext4_xattr_get()
 690  *
 691  * Copy an extended attribute into the buffer
 692  * provided, or compute the buffer size required.
 693  * Buffer is NULL to compute the size of the buffer required.
 694  *
 695  * Returns a negative error number on failure, or the number of bytes
 696  * used / required on success.
 697  */
 698 int
 699 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 700                void *buffer, size_t buffer_size)
 701 {
 702         int error;
 703
 704         if (unlikely(ext4_forced_shutdown(inode->i_sb)))
 705                 return -EIO;
 706
 707         if (strlen(name) > 255)
 708                 return -ERANGE;
 709
 710         down_read(&EXT4_I(inode)->xattr_sem);
 711         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 712                                      buffer_size);
 713         if (error == -ENODATA)
 714                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 715                                              buffer_size);
 716         up_read(&EXT4_I(inode)->xattr_sem);
 717         return error;
 718 }
 719
 720 static int
 721 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 722                         char *buffer, size_t buffer_size)
 723 {
 724         size_t rest = buffer_size;
 725
 726         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 727                 const char *prefix;
 728
 729                 prefix = ext4_xattr_prefix(entry->e_name_index, dentry);
 730                 if (prefix) {
 731                         size_t prefix_len = strlen(prefix);
 732                         size_t size = prefix_len + entry->e_name_len + 1;
 733
 734                         if (buffer) {
 735                                 if (size > rest)
 736                                         return -ERANGE;
 737                                 memcpy(buffer, prefix, prefix_len);
 738                                 buffer += prefix_len;
 739                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 740                                 buffer += entry->e_name_len;
 741                                 *buffer++ = 0;
 742                         }
 743                         rest -= size;
 744                 }
 745         }
 746         return buffer_size - rest;  /* total size */
 747 }
 748
 749 static int
 750 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 751 {
 752         struct inode *inode = d_inode(dentry);
 753         struct buffer_head *bh = NULL;
 754         int error;
 755
 756         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 757                   buffer, (long)buffer_size);
 758
 759         if (!EXT4_I(inode)->i_file_acl)
 760                 return 0;
 761         ea_idebug(inode, "reading block %llu",
 762                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 763         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 764         if (IS_ERR(bh))
 765                 return PTR_ERR(bh);
 766         ea_bdebug(bh, "b_count=%d, refcount=%d",
 767                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 768         error = ext4_xattr_check_block(inode, bh);
 769         if (error)
 770                 goto cleanup;
 771         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 772         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
 773                                         buffer_size);
 774 cleanup:
 775         brelse(bh);
 776         return error;
 777 }
 778
 779 static int
 780 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 781 {
 782         struct inode *inode = d_inode(dentry);
 783         struct ext4_xattr_ibody_header *header;
 784         struct ext4_inode *raw_inode;
 785         struct ext4_iloc iloc;
 786         void *end;
 787         int error;
 788
 789         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 790                 return 0;
 791         error = ext4_get_inode_loc(inode, &iloc);
 792         if (error)
 793                 return error;
 794         raw_inode = ext4_raw_inode(&iloc);
 795         header = IHDR(inode, raw_inode);
 796         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 797         error = xattr_check_inode(inode, header, end);
 798         if (error)
 799                 goto cleanup;
 800         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 801                                         buffer, buffer_size);
 802
 803 cleanup:
 804         brelse(iloc.bh);
 805         return error;
 806 }
 807
 808 /*
 809  * Inode operation listxattr()
 810  *
 811  * d_inode(dentry)->i_rwsem: don't care
 812  *
 813  * Copy a list of attribute names into the buffer
 814  * provided, or compute the buffer size required.
 815  * Buffer is NULL to compute the size of the buffer required.
 816  *
 817  * Returns a negative error number on failure, or the number of bytes
 818  * used / required on success.
 819  */
 820 ssize_t
 821 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 822 {
 823         int ret, ret2;
 824
 825         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 826         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 827         if (ret < 0)
 828                 goto errout;
 829         if (buffer) {
 830                 buffer += ret;
 831                 buffer_size -= ret;
 832         }
 833         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 834         if (ret < 0)
 835                 goto errout;
 836         ret += ret2;
 837 errout:
 838         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 839         return ret;
 840 }
 841
 842 /*
 843  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 844  * not set, set it.
 845  */
 846 static void ext4_xattr_update_super_block(handle_t *handle,
 847                                           struct super_block *sb)
 848 {
 849         if (ext4_has_feature_xattr(sb))
 850                 return;
 851
 852         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 853         if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 854                                           EXT4_JTR_NONE) == 0) {
 855                 lock_buffer(EXT4_SB(sb)->s_sbh);
 856                 ext4_set_feature_xattr(sb);
 857                 ext4_superblock_csum_set(sb);
 858                 unlock_buffer(EXT4_SB(sb)->s_sbh);
 859                 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 860         }
 861 }
 862
 863 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 864 {
 865         struct ext4_iloc iloc = { .bh = NULL };
 866         struct buffer_head *bh = NULL;
 867         struct ext4_inode *raw_inode;
 868         struct ext4_xattr_ibody_header *header;
 869         struct ext4_xattr_entry *entry;
 870         qsize_t ea_inode_refs = 0;
 871         void *end;
 872         int ret;
 873
 874         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 875
 876         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 877                 ret = ext4_get_inode_loc(inode, &iloc);
 878                 if (ret)
 879                         goto out;
 880                 raw_inode = ext4_raw_inode(&iloc);
 881                 header = IHDR(inode, raw_inode);
 882                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 883                 ret = xattr_check_inode(inode, header, end);
 884                 if (ret)
 885                         goto out;
 886
 887                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 888                      entry = EXT4_XATTR_NEXT(entry))
 889                         if (entry->e_value_inum)
 890                                 ea_inode_refs++;
 891         }
 892
 893         if (EXT4_I(inode)->i_file_acl) {
 894                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 895                 if (IS_ERR(bh)) {
 896                         ret = PTR_ERR(bh);
 897                         bh = NULL;
 898                         goto out;
 899                 }
 900
 901                 ret = ext4_xattr_check_block(inode, bh);
 902                 if (ret)
 903                         goto out;
 904
 905                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 906                      entry = EXT4_XATTR_NEXT(entry))
 907                         if (entry->e_value_inum)
 908                                 ea_inode_refs++;
 909         }
 910         *usage = ea_inode_refs + 1;
 911         ret = 0;
 912 out:
 913         brelse(iloc.bh);
 914         brelse(bh);
 915         return ret;
 916 }
 917
 918 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 919 {
 920         struct super_block *sb = inode->i_sb;
 921         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 922                                     inode->i_blkbits);
 923         size_t mask = ~(cluster_size - 1);
 924
 925         return (length + cluster_size - 1) & mask;
 926 }
 927
 928 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 929 {
 930         int err;
 931
 932         err = dquot_alloc_inode(inode);
 933         if (err)
 934                 return err;
 935         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 936         if (err)
 937                 dquot_free_inode(inode);
 938         return err;
 939 }
 940
 941 static void ext4_xattr_inode_free_quota(struct inode *parent,
 942                                         struct inode *ea_inode,
 943                                         size_t len)
 944 {
 945         if (ea_inode &&
 946             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 947                 return;
 948         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 949         dquot_free_inode(parent);
 950 }
 951
 952 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 953                              struct buffer_head *block_bh, size_t value_len,
 954                              bool is_create)
 955 {
 956         int credits;
 957         int blocks;
 958
 959         /*
 960          * 1) Owner inode update
 961          * 2) Ref count update on old xattr block
 962          * 3) new xattr block
 963          * 4) block bitmap update for new xattr block
 964          * 5) group descriptor for new xattr block
 965          * 6) block bitmap update for old xattr block
 966          * 7) group descriptor for old block
 967          *
 968          * 6 & 7 can happen if we have two racing threads T_a and T_b
 969          * which are each trying to set an xattr on inodes I_a and I_b
 970          * which were both initially sharing an xattr block.
 971          */
 972         credits = 7;
 973
 974         /* Quota updates. */
 975         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 976
 977         /*
 978          * In case of inline data, we may push out the data to a block,
 979          * so we need to reserve credits for this eventuality
 980          */
 981         if (inode && ext4_has_inline_data(inode))
 982                 credits += ext4_writepage_trans_blocks(inode) + 1;
 983
 984         /* We are done if ea_inode feature is not enabled. */
 985         if (!ext4_has_feature_ea_inode(sb))
 986                 return credits;
 987
 988         /* New ea_inode, inode map, block bitmap, group descriptor. */
 989         credits += 4;
 990
 991         /* Data blocks. */
 992         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 993
 994         /* Indirection block or one level of extent tree. */
 995         blocks += 1;
 996
 997         /* Block bitmap and group descriptor updates for each block. */
 998         credits += blocks * 2;
 999
1000         /* Blocks themselves. */
1001         credits += blocks;
1002
1003         if (!is_create) {
1004                 /* Dereference ea_inode holding old xattr value.
1005                  * Old ea_inode, inode map, block bitmap, group descriptor.
1006                  */
1007                 credits += 4;
1008
1009                 /* Data blocks for old ea_inode. */
1010                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
1011
1012                 /* Indirection block or one level of extent tree for old
1013                  * ea_inode.
1014                  */
1015                 blocks += 1;
1016
1017                 /* Block bitmap and group descriptor updates for each block. */
1018                 credits += blocks * 2;
1019         }
1020
1021         /* We may need to clone the existing xattr block in which case we need
1022          * to increment ref counts for existing ea_inodes referenced by it.
1023          */
1024         if (block_bh) {
1025                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
1026
1027                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
1028                         if (entry->e_value_inum)
1029                                 /* Ref count update on ea_inode. */
1030                                 credits += 1;
1031         }
1032         return credits;
1033 }
1034
1035 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
1036                                        int ref_change)
1037 {
1038         struct ext4_iloc iloc;
1039         s64 ref_count;
1040         int ret;
1041
1042         inode_lock(ea_inode);
1043
1044         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1045         if (ret)
1046                 goto out;
1047
1048         ref_count = ext4_xattr_inode_get_ref(ea_inode);
1049         ref_count += ref_change;
1050         ext4_xattr_inode_set_ref(ea_inode, ref_count);
1051
1052         if (ref_change > 0) {
1053                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1054                           ea_inode->i_ino, ref_count);
1055
1056                 if (ref_count == 1) {
1057                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1058                                   ea_inode->i_ino, ea_inode->i_nlink);
1059
1060                         set_nlink(ea_inode, 1);
1061                         ext4_orphan_del(handle, ea_inode);
1062                 }
1063         } else {
1064                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1065                           ea_inode->i_ino, ref_count);
1066
1067                 if (ref_count == 0) {
1068                         WARN_ONCE(ea_inode->i_nlink != 1,
1069                                   "EA inode %lu i_nlink=%u",
1070                                   ea_inode->i_ino, ea_inode->i_nlink);
1071
1072                         clear_nlink(ea_inode);
1073                         ext4_orphan_add(handle, ea_inode);
1074                 }
1075         }
1076
1077         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1078         if (ret)
1079                 ext4_warning_inode(ea_inode,
1080                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1081 out:
1082         inode_unlock(ea_inode);
1083         return ret;
1084 }
1085
1086 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1087 {
1088         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1089 }
1090
1091 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1092 {
1093         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1094 }
1095
1096 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1097                                         struct ext4_xattr_entry *first)
1098 {
1099         struct inode *ea_inode;
1100         struct ext4_xattr_entry *entry;
1101         struct ext4_xattr_entry *failed_entry;
1102         unsigned int ea_ino;
1103         int err, saved_err;
1104
1105         for (entry = first; !IS_LAST_ENTRY(entry);
1106              entry = EXT4_XATTR_NEXT(entry)) {
1107                 if (!entry->e_value_inum)
1108                         continue;
1109                 ea_ino = le32_to_cpu(entry->e_value_inum);
1110                 err = ext4_xattr_inode_iget(parent, ea_ino,
1111                                             le32_to_cpu(entry->e_hash),
1112                                             &ea_inode);
1113                 if (err)
1114                         goto cleanup;
1115                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1116                 if (err) {
1117                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1118                         iput(ea_inode);
1119                         goto cleanup;
1120                 }
1121                 iput(ea_inode);
1122         }
1123         return 0;
1124
1125 cleanup:
1126         saved_err = err;
1127         failed_entry = entry;
1128
1129         for (entry = first; entry != failed_entry;
1130              entry = EXT4_XATTR_NEXT(entry)) {
1131                 if (!entry->e_value_inum)
1132                         continue;
1133                 ea_ino = le32_to_cpu(entry->e_value_inum);
1134                 err = ext4_xattr_inode_iget(parent, ea_ino,
1135                                             le32_to_cpu(entry->e_hash),
1136                                             &ea_inode);
1137                 if (err) {
1138                         ext4_warning(parent->i_sb,
1139                                      "cleanup ea_ino %u iget error %d", ea_ino,
1140                                      err);
1141                         continue;
1142                 }
1143                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1144                 if (err)
1145                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1146                                            err);
1147                 iput(ea_inode);
1148         }
1149         return saved_err;
1150 }
1151
1152 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1153                         struct buffer_head *bh, bool block_csum, bool dirty)
1154 {
1155         int error;
1156
1157         if (bh && dirty) {
1158                 if (block_csum)
1159                         ext4_xattr_block_csum_set(inode, bh);
1160                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1161                 if (error) {
1162                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1163                                      error);
1164                         return error;
1165                 }
1166         }
1167         return 0;
1168 }
1169
1170 static void
1171 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1172                              struct buffer_head *bh,
1173                              struct ext4_xattr_entry *first, bool block_csum,
1174                              struct ext4_xattr_inode_array **ea_inode_array,
1175                              int extra_credits, bool skip_quota)
1176 {
1177         struct inode *ea_inode;
1178         struct ext4_xattr_entry *entry;
1179         bool dirty = false;
1180         unsigned int ea_ino;
1181         int err;
1182         int credits;
1183
1184         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1185         credits = 2 + extra_credits;
1186
1187         for (entry = first; !IS_LAST_ENTRY(entry);
1188              entry = EXT4_XATTR_NEXT(entry)) {
1189                 if (!entry->e_value_inum)
1190                         continue;
1191                 ea_ino = le32_to_cpu(entry->e_value_inum);
1192                 err = ext4_xattr_inode_iget(parent, ea_ino,
1193                                             le32_to_cpu(entry->e_hash),
1194                                             &ea_inode);
1195                 if (err)
1196                         continue;
1197
1198                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1199                 if (err) {
1200                         ext4_warning_inode(ea_inode,
1201                                            "Expand inode array err=%d", err);
1202                         iput(ea_inode);
1203                         continue;
1204                 }
1205
1206                 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1207                         ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1208                         ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1209                                               dirty));
1210                 if (err < 0) {
1211                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1212                                            err);
1213                         continue;
1214                 }
1215                 if (err > 0) {
1216                         err = ext4_journal_get_write_access(handle,
1217                                         parent->i_sb, bh, EXT4_JTR_NONE);
1218                         if (err) {
1219                                 ext4_warning_inode(ea_inode,
1220                                                 "Re-get write access err=%d",
1221                                                 err);
1222                                 continue;
1223                         }
1224                 }
1225
1226                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1227                 if (err) {
1228                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1229                                            err);
1230                         continue;
1231                 }
1232
1233                 if (!skip_quota)
1234                         ext4_xattr_inode_free_quota(parent, ea_inode,
1235                                               le32_to_cpu(entry->e_value_size));
1236
1237                 /*
1238                  * Forget about ea_inode within the same transaction that
1239                  * decrements the ref count. This avoids duplicate decrements in
1240                  * case the rest of the work spills over to subsequent
1241                  * transactions.
1242                  */
1243                 entry->e_value_inum = 0;
1244                 entry->e_value_size = 0;
1245
1246                 dirty = true;
1247         }
1248
1249         if (dirty) {
1250                 /*
1251                  * Note that we are deliberately skipping csum calculation for
1252                  * the final update because we do not expect any journal
1253                  * restarts until xattr block is freed.
1254                  */
1255
1256                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1257                 if (err)
1258                         ext4_warning_inode(parent,
1259                                            "handle dirty metadata err=%d", err);
1260         }
1261 }
1262
1263 /*
1264  * Release the xattr block BH: If the reference count is > 1, decrement it;
1265  * otherwise free the block.
1266  */
1267 static void
1268 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1269                          struct buffer_head *bh,
1270                          struct ext4_xattr_inode_array **ea_inode_array,
1271                          int extra_credits)
1272 {
1273         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1274         u32 hash, ref;
1275         int error = 0;
1276
1277         BUFFER_TRACE(bh, "get_write_access");
1278         error = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1279                                               EXT4_JTR_NONE);
1280         if (error)
1281                 goto out;
1282
1283 retry_ref:
1284         lock_buffer(bh);
1285         hash = le32_to_cpu(BHDR(bh)->h_hash);
1286         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1287         if (ref == 1) {
1288                 ea_bdebug(bh, "refcount now=0; freeing");
1289                 /*
1290                  * This must happen under buffer lock for
1291                  * ext4_xattr_block_set() to reliably detect freed block
1292                  */
1293                 if (ea_block_cache) {
1294                         struct mb_cache_entry *oe;
1295
1296                         oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
1297                                                           bh->b_blocknr);
1298                         if (oe) {
1299                                 unlock_buffer(bh);
1300                                 mb_cache_entry_wait_unused(oe);
1301                                 mb_cache_entry_put(ea_block_cache, oe);
1302                                 goto retry_ref;
1303                         }
1304                 }
1305                 get_bh(bh);
1306                 unlock_buffer(bh);
1307
1308                 if (ext4_has_feature_ea_inode(inode->i_sb))
1309                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1310                                                      BFIRST(bh),
1311                                                      true /* block_csum */,
1312                                                      ea_inode_array,
1313                                                      extra_credits,
1314                                                      true /* skip_quota */);
1315                 ext4_free_blocks(handle, inode, bh, 0, 1,
1316                                  EXT4_FREE_BLOCKS_METADATA |
1317                                  EXT4_FREE_BLOCKS_FORGET);
1318         } else {
1319                 ref--;
1320                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1321                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1322                         struct mb_cache_entry *ce;
1323
1324                         if (ea_block_cache) {
1325                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1326                                                         bh->b_blocknr);
1327                                 if (ce) {
1328                                         set_bit(MBE_REUSABLE_B, &ce->e_flags);
1329                                         mb_cache_entry_put(ea_block_cache, ce);
1330                                 }
1331                         }
1332                 }
1333
1334                 ext4_xattr_block_csum_set(inode, bh);
1335                 /*
1336                  * Beware of this ugliness: Releasing of xattr block references
1337                  * from different inodes can race and so we have to protect
1338                  * from a race where someone else frees the block (and releases
1339                  * its journal_head) before we are done dirtying the buffer. In
1340                  * nojournal mode this race is harmless and we actually cannot
1341                  * call ext4_handle_dirty_metadata() with locked buffer as
1342                  * that function can call sync_dirty_buffer() so for that case
1343                  * we handle the dirtying after unlocking the buffer.
1344                  */
1345                 if (ext4_handle_valid(handle))
1346                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1347                 unlock_buffer(bh);
1348                 if (!ext4_handle_valid(handle))
1349                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1350                 if (IS_SYNC(inode))
1351                         ext4_handle_sync(handle);
1352                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1353                 ea_bdebug(bh, "refcount now=%d; releasing",
1354                           le32_to_cpu(BHDR(bh)->h_refcount));
1355         }
1356 out:
1357         ext4_std_error(inode->i_sb, error);
1358         return;
1359 }
1360
1361 /*
1362  * Find the available free space for EAs. This also returns the total number of
1363  * bytes used by EA entries.
1364  */
1365 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1366                                     size_t *min_offs, void *base, int *total)
1367 {
1368         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1369                 if (!last->e_value_inum && last->e_value_size) {
1370                         size_t offs = le16_to_cpu(last->e_value_offs);
1371                         if (offs < *min_offs)
1372                                 *min_offs = offs;
1373                 }
1374                 if (total)
1375                         *total += EXT4_XATTR_LEN(last->e_name_len);
1376         }
1377         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1378 }
1379
1380 /*
1381  * Write the value of the EA in an inode.
1382  */
1383 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1384                                   const void *buf, int bufsize)
1385 {
1386         struct buffer_head *bh = NULL;
1387         unsigned long block = 0;
1388         int blocksize = ea_inode->i_sb->s_blocksize;
1389         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1390         int csize, wsize = 0;
1391         int ret = 0, ret2 = 0;
1392         int retries = 0;
1393
1394 retry:
1395         while (ret >= 0 && ret < max_blocks) {
1396                 struct ext4_map_blocks map;
1397                 map.m_lblk = block += ret;
1398                 map.m_len = max_blocks -= ret;
1399
1400                 ret = ext4_map_blocks(handle, ea_inode, &map,
1401                                       EXT4_GET_BLOCKS_CREATE);
1402                 if (ret <= 0) {
1403                         ext4_mark_inode_dirty(handle, ea_inode);
1404                         if (ret == -ENOSPC &&
1405                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1406                                 ret = 0;
1407                                 goto retry;
1408                         }
1409                         break;
1410                 }
1411         }
1412
1413         if (ret < 0)
1414                 return ret;
1415
1416         block = 0;
1417         while (wsize < bufsize) {
1418                 brelse(bh);
1419                 csize = (bufsize - wsize) > blocksize ? blocksize :
1420                                                                 bufsize - wsize;
1421                 bh = ext4_getblk(handle, ea_inode, block, 0);
1422                 if (IS_ERR(bh))
1423                         return PTR_ERR(bh);
1424                 if (!bh) {
1425                         WARN_ON_ONCE(1);
1426                         EXT4_ERROR_INODE(ea_inode,
1427                                          "ext4_getblk() return bh = NULL");
1428                         return -EFSCORRUPTED;
1429                 }
1430                 ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh,
1431                                                    EXT4_JTR_NONE);
1432                 if (ret)
1433                         goto out;
1434
1435                 memcpy(bh->b_data, buf, csize);
1436                 set_buffer_uptodate(bh);
1437                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1438
1439                 buf += csize;
1440                 wsize += csize;
1441                 block += 1;
1442         }
1443
1444         inode_lock(ea_inode);
1445         i_size_write(ea_inode, wsize);
1446         ext4_update_i_disksize(ea_inode, wsize);
1447         inode_unlock(ea_inode);
1448
1449         ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1450         if (unlikely(ret2 && !ret))
1451                 ret = ret2;
1452
1453 out:
1454         brelse(bh);
1455
1456         return ret;
1457 }
1458
1459 /*
1460  * Create an inode to store the value of a large EA.
1461  */
1462 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1463                                              struct inode *inode, u32 hash)
1464 {
1465         struct inode *ea_inode = NULL;
1466         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1467         int err;
1468
1469         if (inode->i_sb->s_root == NULL) {
1470                 ext4_warning(inode->i_sb,
1471                              "refuse to create EA inode when umounting");
1472                 WARN_ON(1);
1473                 return ERR_PTR(-EINVAL);
1474         }
1475
1476         /*
1477          * Let the next inode be the goal, so we try and allocate the EA inode
1478          * in the same group, or nearby one.
1479          */
1480         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1481                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1482                                   EXT4_EA_INODE_FL);
1483         if (!IS_ERR(ea_inode)) {
1484                 ea_inode->i_op = &ext4_file_inode_operations;
1485                 ea_inode->i_fop = &ext4_file_operations;
1486                 ext4_set_aops(ea_inode);
1487                 ext4_xattr_inode_set_class(ea_inode);
1488                 unlock_new_inode(ea_inode);
1489                 ext4_xattr_inode_set_ref(ea_inode, 1);
1490                 ext4_xattr_inode_set_hash(ea_inode, hash);
1491                 err = ext4_mark_inode_dirty(handle, ea_inode);
1492                 if (!err)
1493                         err = ext4_inode_attach_jinode(ea_inode);
1494                 if (err) {
1495                         if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1496                                 ext4_warning_inode(ea_inode,
1497                                         "cleanup dec ref error %d", err);
1498                         iput(ea_inode);
1499                         return ERR_PTR(err);
1500                 }
1501
1502                 /*
1503                  * Xattr inodes are shared therefore quota charging is performed
1504                  * at a higher level.
1505                  */
1506                 dquot_free_inode(ea_inode);
1507                 dquot_drop(ea_inode);
1508                 inode_lock(ea_inode);
1509                 ea_inode->i_flags |= S_NOQUOTA;
1510                 inode_unlock(ea_inode);
1511         }
1512
1513         return ea_inode;
1514 }
1515
1516 static struct inode *
1517 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1518                             size_t value_len, u32 hash)
1519 {
1520         struct inode *ea_inode;
1521         struct mb_cache_entry *ce;
1522         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1523         void *ea_data;
1524
1525         if (!ea_inode_cache)
1526                 return NULL;
1527
1528         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1529         if (!ce)
1530                 return NULL;
1531
1532         WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1533                      !(current->flags & PF_MEMALLOC_NOFS));
1534
1535         ea_data = kvmalloc(value_len, GFP_KERNEL);
1536         if (!ea_data) {
1537                 mb_cache_entry_put(ea_inode_cache, ce);
1538                 return NULL;
1539         }
1540
1541         while (ce) {
1542                 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1543                                      EXT4_IGET_EA_INODE);
1544                 if (IS_ERR(ea_inode))
1545                         goto next_entry;
1546                 ext4_xattr_inode_set_class(ea_inode);
1547                 if (i_size_read(ea_inode) == value_len &&
1548                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1549                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1550                                                     value_len) &&
1551                     !memcmp(value, ea_data, value_len)) {
1552                         mb_cache_entry_touch(ea_inode_cache, ce);
1553                         mb_cache_entry_put(ea_inode_cache, ce);
1554                         kvfree(ea_data);
1555                         return ea_inode;
1556                 }
1557                 iput(ea_inode);
1558         next_entry:
1559                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1560         }
1561         kvfree(ea_data);
1562         return NULL;
1563 }
1564
1565 /*
1566  * Add value of the EA in an inode.
1567  */
1568 static struct inode *ext4_xattr_inode_lookup_create(handle_t *handle,
1569                 struct inode *inode, const void *value, size_t value_len)
1570 {
1571         struct inode *ea_inode;
1572         u32 hash;
1573         int err;
1574
1575         /* Account inode & space to quota even if sharing... */
1576         err = ext4_xattr_inode_alloc_quota(inode, value_len);
1577         if (err)
1578                 return ERR_PTR(err);
1579
1580         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1581         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1582         if (ea_inode) {
1583                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1584                 if (err)
1585                         goto out_err;
1586                 return ea_inode;
1587         }
1588
1589         /* Create an inode for the EA value */
1590         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1591         if (IS_ERR(ea_inode)) {
1592                 ext4_xattr_inode_free_quota(inode, NULL, value_len);
1593                 return ea_inode;
1594         }
1595
1596         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1597         if (err) {
1598                 if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1599                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d", err);
1600                 goto out_err;
1601         }
1602
1603         if (EA_INODE_CACHE(inode))
1604                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1605                                       ea_inode->i_ino, true /* reusable */);
1606         return ea_inode;
1607 out_err:
1608         iput(ea_inode);
1609         ext4_xattr_inode_free_quota(inode, NULL, value_len);
1610         return ERR_PTR(err);
1611 }
1612
1613 /*
1614  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1615  * feature is enabled.
1616  */
1617 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1618
1619 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1620                                 struct ext4_xattr_search *s,
1621                                 handle_t *handle, struct inode *inode,
1622                                 struct inode *new_ea_inode,
1623                                 bool is_block)
1624 {
1625         struct ext4_xattr_entry *last, *next;
1626         struct ext4_xattr_entry *here = s->here;
1627         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1628         int in_inode = i->in_inode;
1629         struct inode *old_ea_inode = NULL;
1630         size_t old_size, new_size;
1631         int ret;
1632
1633         /* Space used by old and new values. */
1634         old_size = (!s->not_found && !here->e_value_inum) ?
1635                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1636         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1637
1638         /*
1639          * Optimization for the simple case when old and new values have the
1640          * same padded sizes. Not applicable if external inodes are involved.
1641          */
1642         if (new_size && new_size == old_size) {
1643                 size_t offs = le16_to_cpu(here->e_value_offs);
1644                 void *val = s->base + offs;
1645
1646                 here->e_value_size = cpu_to_le32(i->value_len);
1647                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1648                         memset(val, 0, new_size);
1649                 } else {
1650                         memcpy(val, i->value, i->value_len);
1651                         /* Clear padding bytes. */
1652                         memset(val + i->value_len, 0, new_size - i->value_len);
1653                 }
1654                 goto update_hash;
1655         }
1656
1657         /* Compute min_offs and last. */
1658         last = s->first;
1659         for (; !IS_LAST_ENTRY(last); last = next) {
1660                 next = EXT4_XATTR_NEXT(last);
1661                 if ((void *)next >= s->end) {
1662                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1663                         ret = -EFSCORRUPTED;
1664                         goto out;
1665                 }
1666                 if (!last->e_value_inum && last->e_value_size) {
1667                         size_t offs = le16_to_cpu(last->e_value_offs);
1668                         if (offs < min_offs)
1669                                 min_offs = offs;
1670                 }
1671         }
1672
1673         /* Check whether we have enough space. */
1674         if (i->value) {
1675                 size_t free;
1676
1677                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1678                 if (!s->not_found)
1679                         free += EXT4_XATTR_LEN(name_len) + old_size;
1680
1681                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1682                         ret = -ENOSPC;
1683                         goto out;
1684                 }
1685
1686                 /*
1687                  * If storing the value in an external inode is an option,
1688                  * reserve space for xattr entries/names in the external
1689                  * attribute block so that a long value does not occupy the
1690                  * whole space and prevent further entries being added.
1691                  */
1692                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1693                     new_size && is_block &&
1694                     (min_offs + old_size - new_size) <
1695                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1696                         ret = -ENOSPC;
1697                         goto out;
1698                 }
1699         }
1700
1701         /*
1702          * Getting access to old and new ea inodes is subject to failures.
1703          * Finish that work before doing any modifications to the xattr data.
1704          */
1705         if (!s->not_found && here->e_value_inum) {
1706                 ret = ext4_xattr_inode_iget(inode,
1707                                             le32_to_cpu(here->e_value_inum),
1708                                             le32_to_cpu(here->e_hash),
1709                                             &old_ea_inode);
1710                 if (ret) {
1711                         old_ea_inode = NULL;
1712                         goto out;
1713                 }
1714
1715                 /* We are ready to release ref count on the old_ea_inode. */
1716                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1717                 if (ret)
1718                         goto out;
1719
1720                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1721                                             le32_to_cpu(here->e_value_size));
1722         }
1723
1724         /* No failures allowed past this point. */
1725
1726         if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1727                 /* Remove the old value. */
1728                 void *first_val = s->base + min_offs;
1729                 size_t offs = le16_to_cpu(here->e_value_offs);
1730                 void *val = s->base + offs;
1731
1732                 memmove(first_val + old_size, first_val, val - first_val);
1733                 memset(first_val, 0, old_size);
1734                 min_offs += old_size;
1735
1736                 /* Adjust all value offsets. */
1737                 last = s->first;
1738                 while (!IS_LAST_ENTRY(last)) {
1739                         size_t o = le16_to_cpu(last->e_value_offs);
1740
1741                         if (!last->e_value_inum &&
1742                             last->e_value_size && o < offs)
1743                                 last->e_value_offs = cpu_to_le16(o + old_size);
1744                         last = EXT4_XATTR_NEXT(last);
1745                 }
1746         }
1747
1748         if (!i->value) {
1749                 /* Remove old name. */
1750                 size_t size = EXT4_XATTR_LEN(name_len);
1751
1752                 last = ENTRY((void *)last - size);
1753                 memmove(here, (void *)here + size,
1754                         (void *)last - (void *)here + sizeof(__u32));
1755                 memset(last, 0, size);
1756
1757                 /*
1758                  * Update i_inline_off - moved ibody region might contain
1759                  * system.data attribute.  Handling a failure here won't
1760                  * cause other complications for setting an xattr.
1761                  */
1762                 if (!is_block && ext4_has_inline_data(inode)) {
1763                         ret = ext4_find_inline_data_nolock(inode);
1764                         if (ret) {
1765                                 ext4_warning_inode(inode,
1766                                         "unable to update i_inline_off");
1767                                 goto out;
1768                         }
1769                 }
1770         } else if (s->not_found) {
1771                 /* Insert new name. */
1772                 size_t size = EXT4_XATTR_LEN(name_len);
1773                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1774
1775                 memmove((void *)here + size, here, rest);
1776                 memset(here, 0, size);
1777                 here->e_name_index = i->name_index;
1778                 here->e_name_len = name_len;
1779                 memcpy(here->e_name, i->name, name_len);
1780         } else {
1781                 /* This is an update, reset value info. */
1782                 here->e_value_inum = 0;
1783                 here->e_value_offs = 0;
1784                 here->e_value_size = 0;
1785         }
1786
1787         if (i->value) {
1788                 /* Insert new value. */
1789                 if (in_inode) {
1790                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1791                 } else if (i->value_len) {
1792                         void *val = s->base + min_offs - new_size;
1793
1794                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1795                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1796                                 memset(val, 0, new_size);
1797                         } else {
1798                                 memcpy(val, i->value, i->value_len);
1799                                 /* Clear padding bytes. */
1800                                 memset(val + i->value_len, 0,
1801                                        new_size - i->value_len);
1802                         }
1803                 }
1804                 here->e_value_size = cpu_to_le32(i->value_len);
1805         }
1806
1807 update_hash:
1808         if (i->value) {
1809                 __le32 hash = 0;
1810
1811                 /* Entry hash calculation. */
1812                 if (in_inode) {
1813                         __le32 crc32c_hash;
1814
1815                         /*
1816                          * Feed crc32c hash instead of the raw value for entry
1817                          * hash calculation. This is to avoid walking
1818                          * potentially long value buffer again.
1819                          */
1820                         crc32c_hash = cpu_to_le32(
1821                                        ext4_xattr_inode_get_hash(new_ea_inode));
1822                         hash = ext4_xattr_hash_entry(here->e_name,
1823                                                      here->e_name_len,
1824                                                      &crc32c_hash, 1);
1825                 } else if (is_block) {
1826                         __le32 *value = s->base + le16_to_cpu(
1827                                                         here->e_value_offs);
1828
1829                         hash = ext4_xattr_hash_entry(here->e_name,
1830                                                      here->e_name_len, value,
1831                                                      new_size >> 2);
1832                 }
1833                 here->e_hash = hash;
1834         }
1835
1836         if (is_block)
1837                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1838
1839         ret = 0;
1840 out:
1841         iput(old_ea_inode);
1842         return ret;
1843 }
1844
1845 struct ext4_xattr_block_find {
1846         struct ext4_xattr_search s;
1847         struct buffer_head *bh;
1848 };
1849
1850 static int
1851 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1852                       struct ext4_xattr_block_find *bs)
1853 {
1854         struct super_block *sb = inode->i_sb;
1855         int error;
1856
1857         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1858                   i->name_index, i->name, i->value, (long)i->value_len);
1859
1860         if (EXT4_I(inode)->i_file_acl) {
1861                 /* The inode already has an extended attribute block. */
1862                 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1863                 if (IS_ERR(bs->bh)) {
1864                         error = PTR_ERR(bs->bh);
1865                         bs->bh = NULL;
1866                         return error;
1867                 }
1868                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1869                         atomic_read(&(bs->bh->b_count)),
1870                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1871                 error = ext4_xattr_check_block(inode, bs->bh);
1872                 if (error)
1873                         return error;
1874                 /* Find the named attribute. */
1875                 bs->s.base = BHDR(bs->bh);
1876                 bs->s.first = BFIRST(bs->bh);
1877                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1878                 bs->s.here = bs->s.first;
1879                 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1880                                          i->name_index, i->name, 1);
1881                 if (error && error != -ENODATA)
1882                         return error;
1883                 bs->s.not_found = error;
1884         }
1885         return 0;
1886 }
1887
1888 static int
1889 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1890                      struct ext4_xattr_info *i,
1891                      struct ext4_xattr_block_find *bs)
1892 {
1893         struct super_block *sb = inode->i_sb;
1894         struct buffer_head *new_bh = NULL;
1895         struct ext4_xattr_search s_copy = bs->s;
1896         struct ext4_xattr_search *s = &s_copy;
1897         struct mb_cache_entry *ce = NULL;
1898         int error = 0;
1899         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1900         struct inode *ea_inode = NULL, *tmp_inode;
1901         size_t old_ea_inode_quota = 0;
1902         unsigned int ea_ino;
1903
1904 #define header(x) ((struct ext4_xattr_header *)(x))
1905
1906         /* If we need EA inode, prepare it before locking the buffer */
1907         if (i->value && i->in_inode) {
1908                 WARN_ON_ONCE(!i->value_len);
1909
1910                 ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
1911                                         i->value, i->value_len);
1912                 if (IS_ERR(ea_inode)) {
1913                         error = PTR_ERR(ea_inode);
1914                         ea_inode = NULL;
1915                         goto cleanup;
1916                 }
1917         }
1918
1919         if (s->base) {
1920                 int offset = (char *)s->here - bs->bh->b_data;
1921
1922                 BUFFER_TRACE(bs->bh, "get_write_access");
1923                 error = ext4_journal_get_write_access(handle, sb, bs->bh,
1924                                                       EXT4_JTR_NONE);
1925                 if (error)
1926                         goto cleanup;
1927
1928                 lock_buffer(bs->bh);
1929
1930                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1931                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1932
1933                         /*
1934                          * This must happen under buffer lock for
1935                          * ext4_xattr_block_set() to reliably detect modified
1936                          * block
1937                          */
1938                         if (ea_block_cache) {
1939                                 struct mb_cache_entry *oe;
1940
1941                                 oe = mb_cache_entry_delete_or_get(ea_block_cache,
1942                                         hash, bs->bh->b_blocknr);
1943                                 if (oe) {
1944                                         /*
1945                                          * Xattr block is getting reused. Leave
1946                                          * it alone.
1947                                          */
1948                                         mb_cache_entry_put(ea_block_cache, oe);
1949                                         goto clone_block;
1950                                 }
1951                         }
1952                         ea_bdebug(bs->bh, "modifying in-place");
1953                         error = ext4_xattr_set_entry(i, s, handle, inode,
1954                                              ea_inode, true /* is_block */);
1955                         ext4_xattr_block_csum_set(inode, bs->bh);
1956                         unlock_buffer(bs->bh);
1957                         if (error == -EFSCORRUPTED)
1958                                 goto bad_block;
1959                         if (!error)
1960                                 error = ext4_handle_dirty_metadata(handle,
1961                                                                    inode,
1962                                                                    bs->bh);
1963                         if (error)
1964                                 goto cleanup;
1965                         goto inserted;
1966                 }
1967 clone_block:
1968                 unlock_buffer(bs->bh);
1969                 ea_bdebug(bs->bh, "cloning");
1970                 s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
1971                 error = -ENOMEM;
1972                 if (s->base == NULL)
1973                         goto cleanup;
1974                 s->first = ENTRY(header(s->base)+1);
1975                 header(s->base)->h_refcount = cpu_to_le32(1);
1976                 s->here = ENTRY(s->base + offset);
1977                 s->end = s->base + bs->bh->b_size;
1978
1979                 /*
1980                  * If existing entry points to an xattr inode, we need
1981                  * to prevent ext4_xattr_set_entry() from decrementing
1982                  * ref count on it because the reference belongs to the
1983                  * original block. In this case, make the entry look
1984                  * like it has an empty value.
1985                  */
1986                 if (!s->not_found && s->here->e_value_inum) {
1987                         ea_ino = le32_to_cpu(s->here->e_value_inum);
1988                         error = ext4_xattr_inode_iget(inode, ea_ino,
1989                                       le32_to_cpu(s->here->e_hash),
1990                                       &tmp_inode);
1991                         if (error)
1992                                 goto cleanup;
1993
1994                         if (!ext4_test_inode_state(tmp_inode,
1995                                         EXT4_STATE_LUSTRE_EA_INODE)) {
1996                                 /*
1997                                  * Defer quota free call for previous
1998                                  * inode until success is guaranteed.
1999                                  */
2000                                 old_ea_inode_quota = le32_to_cpu(
2001                                                 s->here->e_value_size);
2002                         }
2003                         iput(tmp_inode);
2004
2005                         s->here->e_value_inum = 0;
2006                         s->here->e_value_size = 0;
2007                 }
2008         } else {
2009                 /* Allocate a buffer where we construct the new block. */
2010                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
2011                 error = -ENOMEM;
2012                 if (s->base == NULL)
2013                         goto cleanup;
2014                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2015                 header(s->base)->h_blocks = cpu_to_le32(1);
2016                 header(s->base)->h_refcount = cpu_to_le32(1);
2017                 s->first = ENTRY(header(s->base)+1);
2018                 s->here = ENTRY(header(s->base)+1);
2019                 s->end = s->base + sb->s_blocksize;
2020         }
2021
2022         error = ext4_xattr_set_entry(i, s, handle, inode, ea_inode,
2023                                      true /* is_block */);
2024         if (error == -EFSCORRUPTED)
2025                 goto bad_block;
2026         if (error)
2027                 goto cleanup;
2028
2029 inserted:
2030         if (!IS_LAST_ENTRY(s->first)) {
2031                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base), &ce);
2032                 if (IS_ERR(new_bh)) {
2033                         error = PTR_ERR(new_bh);
2034                         new_bh = NULL;
2035                         goto cleanup;
2036                 }
2037
2038                 if (new_bh) {
2039                         /* We found an identical block in the cache. */
2040                         if (new_bh == bs->bh)
2041                                 ea_bdebug(new_bh, "keeping");
2042                         else {
2043                                 u32 ref;
2044
2045 #ifdef EXT4_XATTR_DEBUG
2046                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
2047 #endif
2048                                 /* The old block is released after updating
2049                                    the inode. */
2050                                 error = dquot_alloc_block(inode,
2051                                                 EXT4_C2B(EXT4_SB(sb), 1));
2052                                 if (error)
2053                                         goto cleanup;
2054                                 BUFFER_TRACE(new_bh, "get_write_access");
2055                                 error = ext4_journal_get_write_access(
2056                                                 handle, sb, new_bh,
2057                                                 EXT4_JTR_NONE);
2058                                 if (error)
2059                                         goto cleanup_dquot;
2060                                 lock_buffer(new_bh);
2061                                 /*
2062                                  * We have to be careful about races with
2063                                  * adding references to xattr block. Once we
2064                                  * hold buffer lock xattr block's state is
2065                                  * stable so we can check the additional
2066                                  * reference fits.
2067                                  */
2068                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2069                                 if (ref > EXT4_XATTR_REFCOUNT_MAX) {
2070                                         /*
2071                                          * Undo everything and check mbcache
2072                                          * again.
2073                                          */
2074                                         unlock_buffer(new_bh);
2075                                         dquot_free_block(inode,
2076                                                          EXT4_C2B(EXT4_SB(sb),
2077                                                                   1));
2078                                         brelse(new_bh);
2079                                         mb_cache_entry_put(ea_block_cache, ce);
2080                                         ce = NULL;
2081                                         new_bh = NULL;
2082                                         goto inserted;
2083                                 }
2084                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2085                                 if (ref == EXT4_XATTR_REFCOUNT_MAX)
2086                                         clear_bit(MBE_REUSABLE_B, &ce->e_flags);
2087                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2088                                           ref);
2089                                 ext4_xattr_block_csum_set(inode, new_bh);
2090                                 unlock_buffer(new_bh);
2091                                 error = ext4_handle_dirty_metadata(handle,
2092                                                                    inode,
2093                                                                    new_bh);
2094                                 if (error)
2095                                         goto cleanup_dquot;
2096                         }
2097                         mb_cache_entry_touch(ea_block_cache, ce);
2098                         mb_cache_entry_put(ea_block_cache, ce);
2099                         ce = NULL;
2100                 } else if (bs->bh && s->base == bs->bh->b_data) {
2101                         /* We were modifying this block in-place. */
2102                         ea_bdebug(bs->bh, "keeping this block");
2103                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2104                         new_bh = bs->bh;
2105                         get_bh(new_bh);
2106                 } else {
2107                         /* We need to allocate a new block */
2108                         ext4_fsblk_t goal, block;
2109
2110 #ifdef EXT4_XATTR_DEBUG
2111                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2112 #endif
2113                         goal = ext4_group_first_block_no(sb,
2114                                                 EXT4_I(inode)->i_block_group);
2115                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2116                                                      NULL, &error);
2117                         if (error)
2118                                 goto cleanup;
2119
2120                         ea_idebug(inode, "creating block %llu",
2121                                   (unsigned long long)block);
2122
2123                         new_bh = sb_getblk(sb, block);
2124                         if (unlikely(!new_bh)) {
2125                                 error = -ENOMEM;
2126 getblk_failed:
2127                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2128                                                  EXT4_FREE_BLOCKS_METADATA);
2129                                 goto cleanup;
2130                         }
2131                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2132                                                       ENTRY(header(s->base)+1));
2133                         if (error)
2134                                 goto getblk_failed;
2135                         if (ea_inode) {
2136                                 /* Drop the extra ref on ea_inode. */
2137                                 error = ext4_xattr_inode_dec_ref(handle,
2138                                                                  ea_inode);
2139                                 if (error)
2140                                         ext4_warning_inode(ea_inode,
2141                                                            "dec ref error=%d",
2142                                                            error);
2143                                 iput(ea_inode);
2144                                 ea_inode = NULL;
2145                         }
2146
2147                         lock_buffer(new_bh);
2148                         error = ext4_journal_get_create_access(handle, sb,
2149                                                         new_bh, EXT4_JTR_NONE);
2150                         if (error) {
2151                                 unlock_buffer(new_bh);
2152                                 error = -EIO;
2153                                 goto getblk_failed;
2154                         }
2155                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2156                         ext4_xattr_block_csum_set(inode, new_bh);
2157                         set_buffer_uptodate(new_bh);
2158                         unlock_buffer(new_bh);
2159                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2160                         error = ext4_handle_dirty_metadata(handle, inode,
2161                                                            new_bh);
2162                         if (error)
2163                                 goto cleanup;
2164                 }
2165         }
2166
2167         if (old_ea_inode_quota)
2168                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2169
2170         /* Update the inode. */
2171         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2172
2173         /* Drop the previous xattr block. */
2174         if (bs->bh && bs->bh != new_bh) {
2175                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2176
2177                 ext4_xattr_release_block(handle, inode, bs->bh,
2178                                          &ea_inode_array,
2179                                          0 /* extra_credits */);
2180                 ext4_xattr_inode_array_free(ea_inode_array);
2181         }
2182         error = 0;
2183
2184 cleanup:
2185         if (ea_inode) {
2186                 if (error) {
2187                         int error2;
2188
2189                         error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2190                         if (error2)
2191                                 ext4_warning_inode(ea_inode, "dec ref error=%d",
2192                                                    error2);
2193                         ext4_xattr_inode_free_quota(inode, ea_inode,
2194                                                     i_size_read(ea_inode));
2195                 }
2196                 iput(ea_inode);
2197         }
2198         if (ce)
2199                 mb_cache_entry_put(ea_block_cache, ce);
2200         brelse(new_bh);
2201         if (!(bs->bh && s->base == bs->bh->b_data))
2202                 kfree(s->base);
2203
2204         return error;
2205
2206 cleanup_dquot:
2207         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2208         goto cleanup;
2209
2210 bad_block:
2211         EXT4_ERROR_INODE(inode, "bad block %llu",
2212                          EXT4_I(inode)->i_file_acl);
2213         goto cleanup;
2214
2215 #undef header
2216 }
2217
2218 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2219                           struct ext4_xattr_ibody_find *is)
2220 {
2221         struct ext4_xattr_ibody_header *header;
2222         struct ext4_inode *raw_inode;
2223         int error;
2224
2225         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2226                 return 0;
2227
2228         raw_inode = ext4_raw_inode(&is->iloc);
2229         header = IHDR(inode, raw_inode);
2230         is->s.base = is->s.first = IFIRST(header);
2231         is->s.here = is->s.first;
2232         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2233         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2234                 error = xattr_check_inode(inode, header, is->s.end);
2235                 if (error)
2236                         return error;
2237                 /* Find the named attribute. */
2238                 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2239                                          i->name_index, i->name, 0);
2240                 if (error && error != -ENODATA)
2241                         return error;
2242                 is->s.not_found = error;
2243         }
2244         return 0;
2245 }
2246
2247 int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2248                                 struct ext4_xattr_info *i,
2249                                 struct ext4_xattr_ibody_find *is)
2250 {
2251         struct ext4_xattr_ibody_header *header;
2252         struct ext4_xattr_search *s = &is->s;
2253         struct inode *ea_inode = NULL;
2254         int error;
2255
2256         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2257                 return -ENOSPC;
2258
2259         /* If we need EA inode, prepare it before locking the buffer */
2260         if (i->value && i->in_inode) {
2261                 WARN_ON_ONCE(!i->value_len);
2262
2263                 ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
2264                                         i->value, i->value_len);
2265                 if (IS_ERR(ea_inode))
2266                         return PTR_ERR(ea_inode);
2267         }
2268         error = ext4_xattr_set_entry(i, s, handle, inode, ea_inode,
2269                                      false /* is_block */);
2270         if (error) {
2271                 if (ea_inode) {
2272                         int error2;
2273
2274                         error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2275                         if (error2)
2276                                 ext4_warning_inode(ea_inode, "dec ref error=%d",
2277                                                    error2);
2278
2279                         ext4_xattr_inode_free_quota(inode, ea_inode,
2280                                                     i_size_read(ea_inode));
2281                         iput(ea_inode);
2282                 }
2283                 return error;
2284         }
2285         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2286         if (!IS_LAST_ENTRY(s->first)) {
2287                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2288                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2289         } else {
2290                 header->h_magic = cpu_to_le32(0);
2291                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2292         }
2293         iput(ea_inode);
2294         return 0;
2295 }
2296
2297 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2298                                  struct ext4_xattr_info *i)
2299 {
2300         void *value;
2301
2302         /* When e_value_inum is set the value is stored externally. */
2303         if (s->here->e_value_inum)
2304                 return 0;
2305         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2306                 return 0;
2307         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2308         return !memcmp(value, i->value, i->value_len);
2309 }
2310
2311 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2312 {
2313         struct buffer_head *bh;
2314         int error;
2315
2316         if (!EXT4_I(inode)->i_file_acl)
2317                 return NULL;
2318         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2319         if (IS_ERR(bh))
2320                 return bh;
2321         error = ext4_xattr_check_block(inode, bh);
2322         if (error) {
2323                 brelse(bh);
2324                 return ERR_PTR(error);
2325         }
2326         return bh;
2327 }
2328
2329 /*
2330  * ext4_xattr_set_handle()
2331  *
2332  * Create, replace or remove an extended attribute for this inode.  Value
2333  * is NULL to remove an existing extended attribute, and non-NULL to
2334  * either replace an existing extended attribute, or create a new extended
2335  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2336  * specify that an extended attribute must exist and must not exist
2337  * previous to the call, respectively.
2338  *
2339  * Returns 0, or a negative error number on failure.
2340  */
2341 int
2342 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2343                       const char *name, const void *value, size_t value_len,
2344                       int flags)
2345 {
2346         struct ext4_xattr_info i = {
2347                 .name_index = name_index,
2348                 .name = name,
2349                 .value = value,
2350                 .value_len = value_len,
2351                 .in_inode = 0,
2352         };
2353         struct ext4_xattr_ibody_find is = {
2354                 .s = { .not_found = -ENODATA, },
2355         };
2356         struct ext4_xattr_block_find bs = {
2357                 .s = { .not_found = -ENODATA, },
2358         };
2359         int no_expand;
2360         int error;
2361
2362         if (!name)
2363                 return -EINVAL;
2364         if (strlen(name) > 255)
2365                 return -ERANGE;
2366
2367         ext4_write_lock_xattr(inode, &no_expand);
2368
2369         /* Check journal credits under write lock. */
2370         if (ext4_handle_valid(handle)) {
2371                 struct buffer_head *bh;
2372                 int credits;
2373
2374                 bh = ext4_xattr_get_block(inode);
2375                 if (IS_ERR(bh)) {
2376                         error = PTR_ERR(bh);
2377                         goto cleanup;
2378                 }
2379
2380                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2381                                                    value_len,
2382                                                    flags & XATTR_CREATE);
2383                 brelse(bh);
2384
2385                 if (jbd2_handle_buffer_credits(handle) < credits) {
2386                         error = -ENOSPC;
2387                         goto cleanup;
2388                 }
2389                 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2390         }
2391
2392         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2393         if (error)
2394                 goto cleanup;
2395
2396         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2397                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2398                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2399                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2400         }
2401
2402         error = ext4_xattr_ibody_find(inode, &i, &is);
2403         if (error)
2404                 goto cleanup;
2405         if (is.s.not_found)
2406                 error = ext4_xattr_block_find(inode, &i, &bs);
2407         if (error)
2408                 goto cleanup;
2409         if (is.s.not_found && bs.s.not_found) {
2410                 error = -ENODATA;
2411                 if (flags & XATTR_REPLACE)
2412                         goto cleanup;
2413                 error = 0;
2414                 if (!value)
2415                         goto cleanup;
2416         } else {
2417                 error = -EEXIST;
2418                 if (flags & XATTR_CREATE)
2419                         goto cleanup;
2420         }
2421
2422         if (!value) {
2423                 if (!is.s.not_found)
2424                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2425                 else if (!bs.s.not_found)
2426                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2427         } else {
2428                 error = 0;
2429                 /* Xattr value did not change? Save us some work and bail out */
2430                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2431                         goto cleanup;
2432                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2433                         goto cleanup;
2434
2435                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2436                     (EXT4_XATTR_SIZE(i.value_len) >
2437                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2438                         i.in_inode = 1;
2439 retry_inode:
2440                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2441                 if (!error && !bs.s.not_found) {
2442                         i.value = NULL;
2443                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2444                 } else if (error == -ENOSPC) {
2445                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2446                                 brelse(bs.bh);
2447                                 bs.bh = NULL;
2448                                 error = ext4_xattr_block_find(inode, &i, &bs);
2449                                 if (error)
2450                                         goto cleanup;
2451                         }
2452                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2453                         if (!error && !is.s.not_found) {
2454                                 i.value = NULL;
2455                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2456                                                              &is);
2457                         } else if (error == -ENOSPC) {
2458                                 /*
2459                                  * Xattr does not fit in the block, store at
2460                                  * external inode if possible.
2461                                  */
2462                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2463                                     i.value_len && !i.in_inode) {
2464                                         i.in_inode = 1;
2465                                         goto retry_inode;
2466                                 }
2467                         }
2468                 }
2469         }
2470         if (!error) {
2471                 ext4_xattr_update_super_block(handle, inode->i_sb);
2472                 inode_set_ctime_current(inode);
2473                 inode_inc_iversion(inode);
2474                 if (!value)
2475                         no_expand = 0;
2476                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2477                 /*
2478                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2479                  * error != 0.
2480                  */
2481                 is.iloc.bh = NULL;
2482                 if (IS_SYNC(inode))
2483                         ext4_handle_sync(handle);
2484         }
2485         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2486
2487 cleanup:
2488         brelse(is.iloc.bh);
2489         brelse(bs.bh);
2490         ext4_write_unlock_xattr(inode, &no_expand);
2491         return error;
2492 }
2493
2494 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2495                            bool is_create, int *credits)
2496 {
2497         struct buffer_head *bh;
2498         int err;
2499
2500         *credits = 0;
2501
2502         if (!EXT4_SB(inode->i_sb)->s_journal)
2503                 return 0;
2504
2505         down_read(&EXT4_I(inode)->xattr_sem);
2506
2507         bh = ext4_xattr_get_block(inode);
2508         if (IS_ERR(bh)) {
2509                 err = PTR_ERR(bh);
2510         } else {
2511                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2512                                                     value_len, is_create);
2513                 brelse(bh);
2514                 err = 0;
2515         }
2516
2517         up_read(&EXT4_I(inode)->xattr_sem);
2518         return err;
2519 }
2520
2521 /*
2522  * ext4_xattr_set()
2523  *
2524  * Like ext4_xattr_set_handle, but start from an inode. This extended
2525  * attribute modification is a filesystem transaction by itself.
2526  *
2527  * Returns 0, or a negative error number on failure.
2528  */
2529 int
2530 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2531                const void *value, size_t value_len, int flags)
2532 {
2533         handle_t *handle;
2534         struct super_block *sb = inode->i_sb;
2535         int error, retries = 0;
2536         int credits;
2537
2538         error = dquot_initialize(inode);
2539         if (error)
2540                 return error;
2541
2542 retry:
2543         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2544                                        &credits);
2545         if (error)
2546                 return error;
2547
2548         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2549         if (IS_ERR(handle)) {
2550                 error = PTR_ERR(handle);
2551         } else {
2552                 int error2;
2553
2554                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2555                                               value, value_len, flags);
2556                 error2 = ext4_journal_stop(handle);
2557                 if (error == -ENOSPC &&
2558                     ext4_should_retry_alloc(sb, &retries))
2559                         goto retry;
2560                 if (error == 0)
2561                         error = error2;
2562         }
2563         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
2564
2565         return error;
2566 }
2567
2568 /*
2569  * Shift the EA entries in the inode to create space for the increased
2570  * i_extra_isize.
2571  */
2572 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2573                                      int value_offs_shift, void *to,
2574                                      void *from, size_t n)
2575 {
2576         struct ext4_xattr_entry *last = entry;
2577         int new_offs;
2578
2579         /* We always shift xattr headers further thus offsets get lower */
2580         BUG_ON(value_offs_shift > 0);
2581
2582         /* Adjust the value offsets of the entries */
2583         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2584                 if (!last->e_value_inum && last->e_value_size) {
2585                         new_offs = le16_to_cpu(last->e_value_offs) +
2586                                                         value_offs_shift;
2587                         last->e_value_offs = cpu_to_le16(new_offs);
2588                 }
2589         }
2590         /* Shift the entries by n bytes */
2591         memmove(to, from, n);
2592 }
2593
2594 /*
2595  * Move xattr pointed to by 'entry' from inode into external xattr block
2596  */
2597 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2598                                     struct ext4_inode *raw_inode,
2599                                     struct ext4_xattr_entry *entry)
2600 {
2601         struct ext4_xattr_ibody_find *is = NULL;
2602         struct ext4_xattr_block_find *bs = NULL;
2603         char *buffer = NULL, *b_entry_name = NULL;
2604         size_t value_size = le32_to_cpu(entry->e_value_size);
2605         struct ext4_xattr_info i = {
2606                 .value = NULL,
2607                 .value_len = 0,
2608                 .name_index = entry->e_name_index,
2609                 .in_inode = !!entry->e_value_inum,
2610         };
2611         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2612         int needs_kvfree = 0;
2613         int error;
2614
2615         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2616         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2617         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2618         if (!is || !bs || !b_entry_name) {
2619                 error = -ENOMEM;
2620                 goto out;
2621         }
2622
2623         is->s.not_found = -ENODATA;
2624         bs->s.not_found = -ENODATA;
2625         is->iloc.bh = NULL;
2626         bs->bh = NULL;
2627
2628         /* Save the entry name and the entry value */
2629         if (entry->e_value_inum) {
2630                 buffer = kvmalloc(value_size, GFP_NOFS);
2631                 if (!buffer) {
2632                         error = -ENOMEM;
2633                         goto out;
2634                 }
2635                 needs_kvfree = 1;
2636                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2637                 if (error)
2638                         goto out;
2639         } else {
2640                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2641                 buffer = (void *)IFIRST(header) + value_offs;
2642         }
2643
2644         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2645         b_entry_name[entry->e_name_len] = '\0';
2646         i.name = b_entry_name;
2647
2648         error = ext4_get_inode_loc(inode, &is->iloc);
2649         if (error)
2650                 goto out;
2651
2652         error = ext4_xattr_ibody_find(inode, &i, is);
2653         if (error)
2654                 goto out;
2655
2656         i.value = buffer;
2657         i.value_len = value_size;
2658         error = ext4_xattr_block_find(inode, &i, bs);
2659         if (error)
2660                 goto out;
2661
2662         /* Move ea entry from the inode into the block */
2663         error = ext4_xattr_block_set(handle, inode, &i, bs);
2664         if (error)
2665                 goto out;
2666
2667         /* Remove the chosen entry from the inode */
2668         i.value = NULL;
2669         i.value_len = 0;
2670         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2671
2672 out:
2673         kfree(b_entry_name);
2674         if (needs_kvfree && buffer)
2675                 kvfree(buffer);
2676         if (is)
2677                 brelse(is->iloc.bh);
2678         if (bs)
2679                 brelse(bs->bh);
2680         kfree(is);
2681         kfree(bs);
2682
2683         return error;
2684 }
2685
2686 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2687                                        struct ext4_inode *raw_inode,
2688                                        int isize_diff, size_t ifree,
2689                                        size_t bfree, int *total_ino)
2690 {
2691         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2692         struct ext4_xattr_entry *small_entry;
2693         struct ext4_xattr_entry *entry;
2694         struct ext4_xattr_entry *last;
2695         unsigned int entry_size;        /* EA entry size */
2696         unsigned int total_size;        /* EA entry size + value size */
2697         unsigned int min_total_size;
2698         int error;
2699
2700         while (isize_diff > ifree) {
2701                 entry = NULL;
2702                 small_entry = NULL;
2703                 min_total_size = ~0U;
2704                 last = IFIRST(header);
2705                 /* Find the entry best suited to be pushed into EA block */
2706                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2707                         /* never move system.data out of the inode */
2708                         if ((last->e_name_len == 4) &&
2709                             (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2710                             !memcmp(last->e_name, "data", 4))
2711                                 continue;
2712                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2713                         if (!last->e_value_inum)
2714                                 total_size += EXT4_XATTR_SIZE(
2715                                                le32_to_cpu(last->e_value_size));
2716                         if (total_size <= bfree &&
2717                             total_size < min_total_size) {
2718                                 if (total_size + ifree < isize_diff) {
2719                                         small_entry = last;
2720                                 } else {
2721                                         entry = last;
2722                                         min_total_size = total_size;
2723                                 }
2724                         }
2725                 }
2726
2727                 if (entry == NULL) {
2728                         if (small_entry == NULL)
2729                                 return -ENOSPC;
2730                         entry = small_entry;
2731                 }
2732
2733                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2734                 total_size = entry_size;
2735                 if (!entry->e_value_inum)
2736                         total_size += EXT4_XATTR_SIZE(
2737                                               le32_to_cpu(entry->e_value_size));
2738                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2739                                                  entry);
2740                 if (error)
2741                         return error;
2742
2743                 *total_ino -= entry_size;
2744                 ifree += total_size;
2745                 bfree -= total_size;
2746         }
2747
2748         return 0;
2749 }
2750
2751 /*
2752  * Expand an inode by new_extra_isize bytes when EAs are present.
2753  * Returns 0 on success or negative error number on failure.
2754  */
2755 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2756                                struct ext4_inode *raw_inode, handle_t *handle)
2757 {
2758         struct ext4_xattr_ibody_header *header;
2759         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2760         static unsigned int mnt_count;
2761         size_t min_offs;
2762         size_t ifree, bfree;
2763         int total_ino;
2764         void *base, *end;
2765         int error = 0, tried_min_extra_isize = 0;
2766         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2767         int isize_diff; /* How much do we need to grow i_extra_isize */
2768
2769 retry:
2770         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2771         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2772                 return 0;
2773
2774         header = IHDR(inode, raw_inode);
2775
2776         /*
2777          * Check if enough free space is available in the inode to shift the
2778          * entries ahead by new_extra_isize.
2779          */
2780
2781         base = IFIRST(header);
2782         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2783         min_offs = end - base;
2784         total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2785
2786         error = xattr_check_inode(inode, header, end);
2787         if (error)
2788                 goto cleanup;
2789
2790         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2791         if (ifree >= isize_diff)
2792                 goto shift;
2793
2794         /*
2795          * Enough free space isn't available in the inode, check if
2796          * EA block can hold new_extra_isize bytes.
2797          */
2798         if (EXT4_I(inode)->i_file_acl) {
2799                 struct buffer_head *bh;
2800
2801                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2802                 if (IS_ERR(bh)) {
2803                         error = PTR_ERR(bh);
2804                         goto cleanup;
2805                 }
2806                 error = ext4_xattr_check_block(inode, bh);
2807                 if (error) {
2808                         brelse(bh);
2809                         goto cleanup;
2810                 }
2811                 base = BHDR(bh);
2812                 end = bh->b_data + bh->b_size;
2813                 min_offs = end - base;
2814                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2815                                               NULL);
2816                 brelse(bh);
2817                 if (bfree + ifree < isize_diff) {
2818                         if (!tried_min_extra_isize && s_min_extra_isize) {
2819                                 tried_min_extra_isize++;
2820                                 new_extra_isize = s_min_extra_isize;
2821                                 goto retry;
2822                         }
2823                         error = -ENOSPC;
2824                         goto cleanup;
2825                 }
2826         } else {
2827                 bfree = inode->i_sb->s_blocksize;
2828         }
2829
2830         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2831                                             isize_diff, ifree, bfree,
2832                                             &total_ino);
2833         if (error) {
2834                 if (error == -ENOSPC && !tried_min_extra_isize &&
2835                     s_min_extra_isize) {
2836                         tried_min_extra_isize++;
2837                         new_extra_isize = s_min_extra_isize;
2838                         goto retry;
2839                 }
2840                 goto cleanup;
2841         }
2842 shift:
2843         /* Adjust the offsets and shift the remaining entries ahead */
2844         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2845                         - new_extra_isize, (void *)raw_inode +
2846                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2847                         (void *)header, total_ino);
2848         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2849
2850         if (ext4_has_inline_data(inode))
2851                 error = ext4_find_inline_data_nolock(inode);
2852
2853 cleanup:
2854         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2855                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2856                              inode->i_ino);
2857                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2858         }
2859         return error;
2860 }
2861
2862 #define EIA_INCR 16 /* must be 2^n */
2863 #define EIA_MASK (EIA_INCR - 1)
2864
2865 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2866  * If @ea_inode_array is new or full it will be grown and the old
2867  * contents copied over.
2868  */
2869 static int
2870 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2871                         struct inode *inode)
2872 {
2873         if (*ea_inode_array == NULL) {
2874                 /*
2875                  * Start with 15 inodes, so it fits into a power-of-two size.
2876                  * If *ea_inode_array is NULL, this is essentially offsetof()
2877                  */
2878                 (*ea_inode_array) =
2879                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2880                                          inodes[EIA_MASK]),
2881                                 GFP_NOFS);
2882                 if (*ea_inode_array == NULL)
2883                         return -ENOMEM;
2884                 (*ea_inode_array)->count = 0;
2885         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2886                 /* expand the array once all 15 + n * 16 slots are full */
2887                 struct ext4_xattr_inode_array *new_array = NULL;
2888                 int count = (*ea_inode_array)->count;
2889
2890                 /* if new_array is NULL, this is essentially offsetof() */
2891                 new_array = kmalloc(
2892                                 offsetof(struct ext4_xattr_inode_array,
2893                                          inodes[count + EIA_INCR]),
2894                                 GFP_NOFS);
2895                 if (new_array == NULL)
2896                         return -ENOMEM;
2897                 memcpy(new_array, *ea_inode_array,
2898                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2899                 kfree(*ea_inode_array);
2900                 *ea_inode_array = new_array;
2901         }
2902         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2903         return 0;
2904 }
2905
2906 /*
2907  * ext4_xattr_delete_inode()
2908  *
2909  * Free extended attribute resources associated with this inode. Traverse
2910  * all entries and decrement reference on any xattr inodes associated with this
2911  * inode. This is called immediately before an inode is freed. We have exclusive
2912  * access to the inode. If an orphan inode is deleted it will also release its
2913  * references on xattr block and xattr inodes.
2914  */
2915 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2916                             struct ext4_xattr_inode_array **ea_inode_array,
2917                             int extra_credits)
2918 {
2919         struct buffer_head *bh = NULL;
2920         struct ext4_xattr_ibody_header *header;
2921         struct ext4_iloc iloc = { .bh = NULL };
2922         struct ext4_xattr_entry *entry;
2923         struct inode *ea_inode;
2924         int error;
2925
2926         error = ext4_journal_ensure_credits(handle, extra_credits,
2927                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2928         if (error < 0) {
2929                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2930                 goto cleanup;
2931         }
2932
2933         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2934             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2935
2936                 error = ext4_get_inode_loc(inode, &iloc);
2937                 if (error) {
2938                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2939                         goto cleanup;
2940                 }
2941
2942                 error = ext4_journal_get_write_access(handle, inode->i_sb,
2943                                                 iloc.bh, EXT4_JTR_NONE);
2944                 if (error) {
2945                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2946                                          error);
2947                         goto cleanup;
2948                 }
2949
2950                 header = IHDR(inode, ext4_raw_inode(&iloc));
2951                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2952                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2953                                                      IFIRST(header),
2954                                                      false /* block_csum */,
2955                                                      ea_inode_array,
2956                                                      extra_credits,
2957                                                      false /* skip_quota */);
2958         }
2959
2960         if (EXT4_I(inode)->i_file_acl) {
2961                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2962                 if (IS_ERR(bh)) {
2963                         error = PTR_ERR(bh);
2964                         if (error == -EIO) {
2965                                 EXT4_ERROR_INODE_ERR(inode, EIO,
2966                                                      "block %llu read error",
2967                                                      EXT4_I(inode)->i_file_acl);
2968                         }
2969                         bh = NULL;
2970                         goto cleanup;
2971                 }
2972                 error = ext4_xattr_check_block(inode, bh);
2973                 if (error)
2974                         goto cleanup;
2975
2976                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2977                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2978                              entry = EXT4_XATTR_NEXT(entry)) {
2979                                 if (!entry->e_value_inum)
2980                                         continue;
2981                                 error = ext4_xattr_inode_iget(inode,
2982                                               le32_to_cpu(entry->e_value_inum),
2983                                               le32_to_cpu(entry->e_hash),
2984                                               &ea_inode);
2985                                 if (error)
2986                                         continue;
2987                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2988                                               le32_to_cpu(entry->e_value_size));
2989                                 iput(ea_inode);
2990                         }
2991
2992                 }
2993
2994                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2995                                          extra_credits);
2996                 /*
2997                  * Update i_file_acl value in the same transaction that releases
2998                  * block.
2999                  */
3000                 EXT4_I(inode)->i_file_acl = 0;
3001                 error = ext4_mark_inode_dirty(handle, inode);
3002                 if (error) {
3003                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
3004                                          error);
3005                         goto cleanup;
3006                 }
3007                 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
3008         }
3009         error = 0;
3010 cleanup:
3011         brelse(iloc.bh);
3012         brelse(bh);
3013         return error;
3014 }
3015
3016 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
3017 {
3018         int idx;
3019
3020         if (ea_inode_array == NULL)
3021                 return;
3022
3023         for (idx = 0; idx < ea_inode_array->count; ++idx)
3024                 iput(ea_inode_array->inodes[idx]);
3025         kfree(ea_inode_array);
3026 }
3027
3028 /*
3029  * ext4_xattr_block_cache_insert()
3030  *
3031  * Create a new entry in the extended attribute block cache, and insert
3032  * it unless such an entry is already in the cache.
3033  *
3034  * Returns 0, or a negative error number on failure.
3035  */
3036 static void
3037 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
3038                               struct buffer_head *bh)
3039 {
3040         struct ext4_xattr_header *header = BHDR(bh);
3041         __u32 hash = le32_to_cpu(header->h_hash);
3042         int reusable = le32_to_cpu(header->h_refcount) <
3043                        EXT4_XATTR_REFCOUNT_MAX;
3044         int error;
3045
3046         if (!ea_block_cache)
3047                 return;
3048         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
3049                                       bh->b_blocknr, reusable);
3050         if (error) {
3051                 if (error == -EBUSY)
3052                         ea_bdebug(bh, "already in cache");
3053         } else
3054                 ea_bdebug(bh, "inserting [%x]", (int)hash);
3055 }
3056
3057 /*
3058  * ext4_xattr_cmp()
3059  *
3060  * Compare two extended attribute blocks for equality.
3061  *
3062  * Returns 0 if the blocks are equal, 1 if they differ, and
3063  * a negative error number on errors.
3064  */
3065 static int
3066 ext4_xattr_cmp(struct ext4_xattr_header *header1,
3067                struct ext4_xattr_header *header2)
3068 {
3069         struct ext4_xattr_entry *entry1, *entry2;
3070
3071         entry1 = ENTRY(header1+1);
3072         entry2 = ENTRY(header2+1);
3073         while (!IS_LAST_ENTRY(entry1)) {
3074                 if (IS_LAST_ENTRY(entry2))
3075                         return 1;
3076                 if (entry1->e_hash != entry2->e_hash ||
3077                     entry1->e_name_index != entry2->e_name_index ||
3078                     entry1->e_name_len != entry2->e_name_len ||
3079                     entry1->e_value_size != entry2->e_value_size ||
3080                     entry1->e_value_inum != entry2->e_value_inum ||
3081                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3082                         return 1;
3083                 if (!entry1->e_value_inum &&
3084                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3085                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3086                            le32_to_cpu(entry1->e_value_size)))
3087                         return 1;
3088
3089                 entry1 = EXT4_XATTR_NEXT(entry1);
3090                 entry2 = EXT4_XATTR_NEXT(entry2);
3091         }
3092         if (!IS_LAST_ENTRY(entry2))
3093                 return 1;
3094         return 0;
3095 }
3096
3097 /*
3098  * ext4_xattr_block_cache_find()
3099  *
3100  * Find an identical extended attribute block.
3101  *
3102  * Returns a pointer to the block found, or NULL if such a block was not
3103  * found, or an error pointer if an error occurred while reading ea block.
3104  */
3105 static struct buffer_head *
3106 ext4_xattr_block_cache_find(struct inode *inode,
3107                             struct ext4_xattr_header *header,
3108                             struct mb_cache_entry **pce)
3109 {
3110         __u32 hash = le32_to_cpu(header->h_hash);
3111         struct mb_cache_entry *ce;
3112         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3113
3114         if (!ea_block_cache)
3115                 return NULL;
3116         if (!header->h_hash)
3117                 return NULL;  /* never share */
3118         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3119         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3120         while (ce) {
3121                 struct buffer_head *bh;
3122
3123                 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3124                 if (IS_ERR(bh)) {
3125                         if (PTR_ERR(bh) != -ENOMEM)
3126                                 EXT4_ERROR_INODE(inode, "block %lu read error",
3127                                                  (unsigned long)ce->e_value);
3128                         mb_cache_entry_put(ea_block_cache, ce);
3129                         return bh;
3130                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3131                         *pce = ce;
3132                         return bh;
3133                 }
3134                 brelse(bh);
3135                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3136         }
3137         return NULL;
3138 }
3139
3140 #define NAME_HASH_SHIFT 5
3141 #define VALUE_HASH_SHIFT 16
3142
3143 /*
3144  * ext4_xattr_hash_entry()
3145  *
3146  * Compute the hash of an extended attribute.
3147  */
3148 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3149                                     size_t value_count)
3150 {
3151         __u32 hash = 0;
3152
3153         while (name_len--) {
3154                 hash = (hash << NAME_HASH_SHIFT) ^
3155                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3156                        (unsigned char)*name++;
3157         }
3158         while (value_count--) {
3159                 hash = (hash << VALUE_HASH_SHIFT) ^
3160                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3161                        le32_to_cpu(*value++);
3162         }
3163         return cpu_to_le32(hash);
3164 }
3165
3166 /*
3167  * ext4_xattr_hash_entry_signed()
3168  *
3169  * Compute the hash of an extended attribute incorrectly.
3170  */
3171 static __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value, size_t value_count)
3172 {
3173         __u32 hash = 0;
3174
3175         while (name_len--) {
3176                 hash = (hash << NAME_HASH_SHIFT) ^
3177                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3178                        (signed char)*name++;
3179         }
3180         while (value_count--) {
3181                 hash = (hash << VALUE_HASH_SHIFT) ^
3182                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3183                        le32_to_cpu(*value++);
3184         }
3185         return cpu_to_le32(hash);
3186 }
3187
3188 #undef NAME_HASH_SHIFT
3189 #undef VALUE_HASH_SHIFT
3190
3191 #define BLOCK_HASH_SHIFT 16
3192
3193 /*
3194  * ext4_xattr_rehash()
3195  *
3196  * Re-compute the extended attribute hash value after an entry has changed.
3197  */
3198 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3199 {
3200         struct ext4_xattr_entry *here;
3201         __u32 hash = 0;
3202
3203         here = ENTRY(header+1);
3204         while (!IS_LAST_ENTRY(here)) {
3205                 if (!here->e_hash) {
3206                         /* Block is not shared if an entry's hash value == 0 */
3207                         hash = 0;
3208                         break;
3209                 }
3210                 hash = (hash << BLOCK_HASH_SHIFT) ^
3211                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3212                        le32_to_cpu(here->e_hash);
3213                 here = EXT4_XATTR_NEXT(here);
3214         }
3215         header->h_hash = cpu_to_le32(hash);
3216 }
3217
3218 #undef BLOCK_HASH_SHIFT
3219
3220 #define HASH_BUCKET_BITS        10
3221
3222 struct mb_cache *
3223 ext4_xattr_create_cache(void)
3224 {
3225         return mb_cache_create(HASH_BUCKET_BITS);
3226 }
3227
3228 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3229 {
3230         if (cache)
3231                 mb_cache_destroy(cache);
3232 }
3233