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]  = &posix_acl_access_xattr_handler,
  92         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  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 *ext4_xattr_handlers[] = {
 102         &ext4_xattr_user_handler,
 103         &ext4_xattr_trusted_handler,
 104 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 105         &posix_acl_access_xattr_handler,
 106         &posix_acl_default_xattr_handler,
 107 #endif
 108 #ifdef CONFIG_EXT4_FS_SECURITY
 109         &ext4_xattr_security_handler,
 110 #endif
 111         &ext4_xattr_hurd_handler,
 112         NULL
 113 };
 114
 115 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 116                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 117
 118 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 119                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 120
 121 static int
 122 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 123                         struct inode *inode);
 124
 125 #ifdef CONFIG_LOCKDEP
 126 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 127 {
 128         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 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 struct xattr_handler *
 177 ext4_xattr_handler(int name_index)
 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         return handler;
 184 }
 185
 186 static int
 187 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
 188                          void *value_start)
 189 {
 190         struct ext4_xattr_entry *e = entry;
 191
 192         /* Find the end of the names list */
 193         while (!IS_LAST_ENTRY(e)) {
 194                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 195                 if ((void *)next >= end)
 196                         return -EFSCORRUPTED;
 197                 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
 198                         return -EFSCORRUPTED;
 199                 e = next;
 200         }
 201
 202         /* Check the values */
 203         while (!IS_LAST_ENTRY(entry)) {
 204                 u32 size = le32_to_cpu(entry->e_value_size);
 205
 206                 if (size > EXT4_XATTR_SIZE_MAX)
 207                         return -EFSCORRUPTED;
 208
 209                 if (size != 0 && entry->e_value_inum == 0) {
 210                         u16 offs = le16_to_cpu(entry->e_value_offs);
 211                         void *value;
 212
 213                         /*
 214                          * The value cannot overlap the names, and the value
 215                          * with padding cannot extend beyond 'end'.  Check both
 216                          * the padded and unpadded sizes, since the size may
 217                          * overflow to 0 when adding padding.
 218                          */
 219                         if (offs > end - value_start)
 220                                 return -EFSCORRUPTED;
 221                         value = value_start + offs;
 222                         if (value < (void *)e + sizeof(u32) ||
 223                             size > end - value ||
 224                             EXT4_XATTR_SIZE(size) > end - value)
 225                                 return -EFSCORRUPTED;
 226                 }
 227                 entry = EXT4_XATTR_NEXT(entry);
 228         }
 229
 230         return 0;
 231 }
 232
 233 static inline int
 234 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
 235                          const char *function, unsigned int line)
 236 {
 237         int error = -EFSCORRUPTED;
 238
 239         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 240             BHDR(bh)->h_blocks != cpu_to_le32(1))
 241                 goto errout;
 242         if (buffer_verified(bh))
 243                 return 0;
 244
 245         error = -EFSBADCRC;
 246         if (!ext4_xattr_block_csum_verify(inode, bh))
 247                 goto errout;
 248         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 249                                          bh->b_data);
 250 errout:
 251         if (error)
 252                 __ext4_error_inode(inode, function, line, 0, -error,
 253                                    "corrupted xattr block %llu",
 254                                    (unsigned long long) bh->b_blocknr);
 255         else
 256                 set_buffer_verified(bh);
 257         return error;
 258 }
 259
 260 #define ext4_xattr_check_block(inode, bh) \
 261         __ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
 262
 263
 264 static int
 265 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 266                          void *end, const char *function, unsigned int line)
 267 {
 268         int error = -EFSCORRUPTED;
 269
 270         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 271             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 272                 goto errout;
 273         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 274 errout:
 275         if (error)
 276                 __ext4_error_inode(inode, function, line, 0, -error,
 277                                    "corrupted in-inode xattr");
 278         return error;
 279 }
 280
 281 #define xattr_check_inode(inode, header, end) \
 282         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 283
 284 static int
 285 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
 286                  void *end, int name_index, const char *name, int sorted)
 287 {
 288         struct ext4_xattr_entry *entry, *next;
 289         size_t name_len;
 290         int cmp = 1;
 291
 292         if (name == NULL)
 293                 return -EINVAL;
 294         name_len = strlen(name);
 295         for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
 296                 next = EXT4_XATTR_NEXT(entry);
 297                 if ((void *) next >= end) {
 298                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
 299                         return -EFSCORRUPTED;
 300                 }
 301                 cmp = name_index - entry->e_name_index;
 302                 if (!cmp)
 303                         cmp = name_len - entry->e_name_len;
 304                 if (!cmp)
 305                         cmp = memcmp(name, entry->e_name, name_len);
 306                 if (cmp <= 0 && (sorted || cmp == 0))
 307                         break;
 308         }
 309         *pentry = entry;
 310         return cmp ? -ENODATA : 0;
 311 }
 312
 313 static u32
 314 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 315 {
 316         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 317 }
 318
 319 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 320 {
 321         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 322                 (u32) inode_peek_iversion_raw(ea_inode);
 323 }
 324
 325 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 326 {
 327         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 328         inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
 329 }
 330
 331 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 332 {
 333         return (u32)ea_inode->i_atime.tv_sec;
 334 }
 335
 336 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 337 {
 338         ea_inode->i_atime.tv_sec = hash;
 339 }
 340
 341 /*
 342  * Read the EA value from an inode.
 343  */
 344 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 345 {
 346         int blocksize = 1 << ea_inode->i_blkbits;
 347         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 348         int tail_size = (size % blocksize) ?: blocksize;
 349         struct buffer_head *bhs_inline[8];
 350         struct buffer_head **bhs = bhs_inline;
 351         int i, ret;
 352
 353         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 354                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 355                 if (!bhs)
 356                         return -ENOMEM;
 357         }
 358
 359         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 360                                true /* wait */, bhs);
 361         if (ret)
 362                 goto free_bhs;
 363
 364         for (i = 0; i < bh_count; i++) {
 365                 /* There shouldn't be any holes in ea_inode. */
 366                 if (!bhs[i]) {
 367                         ret = -EFSCORRUPTED;
 368                         goto put_bhs;
 369                 }
 370                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 371                        i < bh_count - 1 ? blocksize : tail_size);
 372         }
 373         ret = 0;
 374 put_bhs:
 375         for (i = 0; i < bh_count; i++)
 376                 brelse(bhs[i]);
 377 free_bhs:
 378         if (bhs != bhs_inline)
 379                 kfree(bhs);
 380         return ret;
 381 }
 382
 383 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 384
 385 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 386                                  u32 ea_inode_hash, struct inode **ea_inode)
 387 {
 388         struct inode *inode;
 389         int err;
 390
 391         inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
 392         if (IS_ERR(inode)) {
 393                 err = PTR_ERR(inode);
 394                 ext4_error(parent->i_sb,
 395                            "error while reading EA inode %lu err=%d", ea_ino,
 396                            err);
 397                 return err;
 398         }
 399
 400         if (is_bad_inode(inode)) {
 401                 ext4_error(parent->i_sb,
 402                            "error while reading EA inode %lu is_bad_inode",
 403                            ea_ino);
 404                 err = -EIO;
 405                 goto error;
 406         }
 407
 408         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 409                 ext4_error(parent->i_sb,
 410                            "EA inode %lu does not have EXT4_EA_INODE_FL flag",
 411                             ea_ino);
 412                 err = -EINVAL;
 413                 goto error;
 414         }
 415
 416         ext4_xattr_inode_set_class(inode);
 417
 418         /*
 419          * Check whether this is an old Lustre-style xattr inode. Lustre
 420          * implementation does not have hash validation, rather it has a
 421          * backpointer from ea_inode to the parent inode.
 422          */
 423         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 424             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 425             inode->i_generation == parent->i_generation) {
 426                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 427                 ext4_xattr_inode_set_ref(inode, 1);
 428         } else {
 429                 inode_lock(inode);
 430                 inode->i_flags |= S_NOQUOTA;
 431                 inode_unlock(inode);
 432         }
 433
 434         *ea_inode = inode;
 435         return 0;
 436 error:
 437         iput(inode);
 438         return err;
 439 }
 440
 441 /* Remove entry from mbcache when EA inode is getting evicted */
 442 void ext4_evict_ea_inode(struct inode *inode)
 443 {
 444         struct mb_cache_entry *oe;
 445
 446         if (!EA_INODE_CACHE(inode))
 447                 return;
 448         /* Wait for entry to get unused so that we can remove it */
 449         while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
 450                         ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
 451                 mb_cache_entry_wait_unused(oe);
 452                 mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
 453         }
 454 }
 455
 456 static int
 457 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 458                                struct ext4_xattr_entry *entry, void *buffer,
 459                                size_t size)
 460 {
 461         u32 hash;
 462
 463         /* Verify stored hash matches calculated hash. */
 464         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 465         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 466                 return -EFSCORRUPTED;
 467
 468         if (entry) {
 469                 __le32 e_hash, tmp_data;
 470
 471                 /* Verify entry hash. */
 472                 tmp_data = cpu_to_le32(hash);
 473                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 474                                                &tmp_data, 1);
 475                 /* All good? */
 476                 if (e_hash == entry->e_hash)
 477                         return 0;
 478
 479                 /*
 480                  * Not good. Maybe the entry hash was calculated
 481                  * using the buggy signed char version?
 482                  */
 483                 e_hash = ext4_xattr_hash_entry_signed(entry->e_name, entry->e_name_len,
 484                                                         &tmp_data, 1);
 485                 if (e_hash == entry->e_hash)
 486                         return 0;
 487
 488                 /* Still no match - bad */
 489                 return -EFSCORRUPTED;
 490         }
 491         return 0;
 492 }
 493
 494 /*
 495  * Read xattr value from the EA inode.
 496  */
 497 static int
 498 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 499                      void *buffer, size_t size)
 500 {
 501         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 502         struct inode *ea_inode;
 503         int err;
 504
 505         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 506                                     le32_to_cpu(entry->e_hash), &ea_inode);
 507         if (err) {
 508                 ea_inode = NULL;
 509                 goto out;
 510         }
 511
 512         if (i_size_read(ea_inode) != size) {
 513                 ext4_warning_inode(ea_inode,
 514                                    "ea_inode file size=%llu entry size=%zu",
 515                                    i_size_read(ea_inode), size);
 516                 err = -EFSCORRUPTED;
 517                 goto out;
 518         }
 519
 520         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 521         if (err)
 522                 goto out;
 523
 524         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 525                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 526                                                      size);
 527                 if (err) {
 528                         ext4_warning_inode(ea_inode,
 529                                            "EA inode hash validation failed");
 530                         goto out;
 531                 }
 532
 533                 if (ea_inode_cache)
 534                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 535                                         ext4_xattr_inode_get_hash(ea_inode),
 536                                         ea_inode->i_ino, true /* reusable */);
 537         }
 538 out:
 539         iput(ea_inode);
 540         return err;
 541 }
 542
 543 static int
 544 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 545                      void *buffer, size_t buffer_size)
 546 {
 547         struct buffer_head *bh = NULL;
 548         struct ext4_xattr_entry *entry;
 549         size_t size;
 550         void *end;
 551         int error;
 552         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 553
 554         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 555                   name_index, name, buffer, (long)buffer_size);
 556
 557         if (!EXT4_I(inode)->i_file_acl)
 558                 return -ENODATA;
 559         ea_idebug(inode, "reading block %llu",
 560                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 561         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 562         if (IS_ERR(bh))
 563                 return PTR_ERR(bh);
 564         ea_bdebug(bh, "b_count=%d, refcount=%d",
 565                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 566         error = ext4_xattr_check_block(inode, bh);
 567         if (error)
 568                 goto cleanup;
 569         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 570         entry = BFIRST(bh);
 571         end = bh->b_data + bh->b_size;
 572         error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
 573         if (error)
 574                 goto cleanup;
 575         size = le32_to_cpu(entry->e_value_size);
 576         error = -ERANGE;
 577         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 578                 goto cleanup;
 579         if (buffer) {
 580                 if (size > buffer_size)
 581                         goto cleanup;
 582                 if (entry->e_value_inum) {
 583                         error = ext4_xattr_inode_get(inode, entry, buffer,
 584                                                      size);
 585                         if (error)
 586                                 goto cleanup;
 587                 } else {
 588                         u16 offset = le16_to_cpu(entry->e_value_offs);
 589                         void *p = bh->b_data + offset;
 590
 591                         if (unlikely(p + size > end))
 592                                 goto cleanup;
 593                         memcpy(buffer, p, size);
 594                 }
 595         }
 596         error = size;
 597
 598 cleanup:
 599         brelse(bh);
 600         return error;
 601 }
 602
 603 int
 604 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 605                      void *buffer, size_t buffer_size)
 606 {
 607         struct ext4_xattr_ibody_header *header;
 608         struct ext4_xattr_entry *entry;
 609         struct ext4_inode *raw_inode;
 610         struct ext4_iloc iloc;
 611         size_t size;
 612         void *end;
 613         int error;
 614
 615         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 616                 return -ENODATA;
 617         error = ext4_get_inode_loc(inode, &iloc);
 618         if (error)
 619                 return error;
 620         raw_inode = ext4_raw_inode(&iloc);
 621         header = IHDR(inode, raw_inode);
 622         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 623         error = xattr_check_inode(inode, header, end);
 624         if (error)
 625                 goto cleanup;
 626         entry = IFIRST(header);
 627         error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
 628         if (error)
 629                 goto cleanup;
 630         size = le32_to_cpu(entry->e_value_size);
 631         error = -ERANGE;
 632         if (unlikely(size > EXT4_XATTR_SIZE_MAX))
 633                 goto cleanup;
 634         if (buffer) {
 635                 if (size > buffer_size)
 636                         goto cleanup;
 637                 if (entry->e_value_inum) {
 638                         error = ext4_xattr_inode_get(inode, entry, buffer,
 639                                                      size);
 640                         if (error)
 641                                 goto cleanup;
 642                 } else {
 643                         u16 offset = le16_to_cpu(entry->e_value_offs);
 644                         void *p = (void *)IFIRST(header) + offset;
 645
 646                         if (unlikely(p + size > end))
 647                                 goto cleanup;
 648                         memcpy(buffer, p, size);
 649                 }
 650         }
 651         error = size;
 652
 653 cleanup:
 654         brelse(iloc.bh);
 655         return error;
 656 }
 657
 658 /*
 659  * ext4_xattr_get()
 660  *
 661  * Copy an extended attribute into the buffer
 662  * provided, or compute the buffer size required.
 663  * Buffer is NULL to compute the size of the buffer required.
 664  *
 665  * Returns a negative error number on failure, or the number of bytes
 666  * used / required on success.
 667  */
 668 int
 669 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 670                void *buffer, size_t buffer_size)
 671 {
 672         int error;
 673
 674         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 675                 return -EIO;
 676
 677         if (strlen(name) > 255)
 678                 return -ERANGE;
 679
 680         down_read(&EXT4_I(inode)->xattr_sem);
 681         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 682                                      buffer_size);
 683         if (error == -ENODATA)
 684                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 685                                              buffer_size);
 686         up_read(&EXT4_I(inode)->xattr_sem);
 687         return error;
 688 }
 689
 690 static int
 691 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 692                         char *buffer, size_t buffer_size)
 693 {
 694         size_t rest = buffer_size;
 695
 696         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 697                 const struct xattr_handler *handler =
 698                         ext4_xattr_handler(entry->e_name_index);
 699
 700                 if (handler && (!handler->list || handler->list(dentry))) {
 701                         const char *prefix = handler->prefix ?: handler->name;
 702                         size_t prefix_len = strlen(prefix);
 703                         size_t size = prefix_len + entry->e_name_len + 1;
 704
 705                         if (buffer) {
 706                                 if (size > rest)
 707                                         return -ERANGE;
 708                                 memcpy(buffer, prefix, prefix_len);
 709                                 buffer += prefix_len;
 710                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 711                                 buffer += entry->e_name_len;
 712                                 *buffer++ = 0;
 713                         }
 714                         rest -= size;
 715                 }
 716         }
 717         return buffer_size - rest;  /* total size */
 718 }
 719
 720 static int
 721 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 722 {
 723         struct inode *inode = d_inode(dentry);
 724         struct buffer_head *bh = NULL;
 725         int error;
 726
 727         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 728                   buffer, (long)buffer_size);
 729
 730         if (!EXT4_I(inode)->i_file_acl)
 731                 return 0;
 732         ea_idebug(inode, "reading block %llu",
 733                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 734         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 735         if (IS_ERR(bh))
 736                 return PTR_ERR(bh);
 737         ea_bdebug(bh, "b_count=%d, refcount=%d",
 738                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 739         error = ext4_xattr_check_block(inode, bh);
 740         if (error)
 741                 goto cleanup;
 742         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 743         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
 744                                         buffer_size);
 745 cleanup:
 746         brelse(bh);
 747         return error;
 748 }
 749
 750 static int
 751 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 752 {
 753         struct inode *inode = d_inode(dentry);
 754         struct ext4_xattr_ibody_header *header;
 755         struct ext4_inode *raw_inode;
 756         struct ext4_iloc iloc;
 757         void *end;
 758         int error;
 759
 760         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 761                 return 0;
 762         error = ext4_get_inode_loc(inode, &iloc);
 763         if (error)
 764                 return error;
 765         raw_inode = ext4_raw_inode(&iloc);
 766         header = IHDR(inode, raw_inode);
 767         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 768         error = xattr_check_inode(inode, header, end);
 769         if (error)
 770                 goto cleanup;
 771         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 772                                         buffer, buffer_size);
 773
 774 cleanup:
 775         brelse(iloc.bh);
 776         return error;
 777 }
 778
 779 /*
 780  * Inode operation listxattr()
 781  *
 782  * d_inode(dentry)->i_rwsem: don't care
 783  *
 784  * Copy a list of attribute names into the buffer
 785  * provided, or compute the buffer size required.
 786  * Buffer is NULL to compute the size of the buffer required.
 787  *
 788  * Returns a negative error number on failure, or the number of bytes
 789  * used / required on success.
 790  */
 791 ssize_t
 792 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 793 {
 794         int ret, ret2;
 795
 796         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 797         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 798         if (ret < 0)
 799                 goto errout;
 800         if (buffer) {
 801                 buffer += ret;
 802                 buffer_size -= ret;
 803         }
 804         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 805         if (ret < 0)
 806                 goto errout;
 807         ret += ret2;
 808 errout:
 809         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 810         return ret;
 811 }
 812
 813 /*
 814  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 815  * not set, set it.
 816  */
 817 static void ext4_xattr_update_super_block(handle_t *handle,
 818                                           struct super_block *sb)
 819 {
 820         if (ext4_has_feature_xattr(sb))
 821                 return;
 822
 823         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 824         if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
 825                                           EXT4_JTR_NONE) == 0) {
 826                 lock_buffer(EXT4_SB(sb)->s_sbh);
 827                 ext4_set_feature_xattr(sb);
 828                 ext4_superblock_csum_set(sb);
 829                 unlock_buffer(EXT4_SB(sb)->s_sbh);
 830                 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 831         }
 832 }
 833
 834 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 835 {
 836         struct ext4_iloc iloc = { .bh = NULL };
 837         struct buffer_head *bh = NULL;
 838         struct ext4_inode *raw_inode;
 839         struct ext4_xattr_ibody_header *header;
 840         struct ext4_xattr_entry *entry;
 841         qsize_t ea_inode_refs = 0;
 842         void *end;
 843         int ret;
 844
 845         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 846
 847         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 848                 ret = ext4_get_inode_loc(inode, &iloc);
 849                 if (ret)
 850                         goto out;
 851                 raw_inode = ext4_raw_inode(&iloc);
 852                 header = IHDR(inode, raw_inode);
 853                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 854                 ret = xattr_check_inode(inode, header, end);
 855                 if (ret)
 856                         goto out;
 857
 858                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 859                      entry = EXT4_XATTR_NEXT(entry))
 860                         if (entry->e_value_inum)
 861                                 ea_inode_refs++;
 862         }
 863
 864         if (EXT4_I(inode)->i_file_acl) {
 865                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
 866                 if (IS_ERR(bh)) {
 867                         ret = PTR_ERR(bh);
 868                         bh = NULL;
 869                         goto out;
 870                 }
 871
 872                 ret = ext4_xattr_check_block(inode, bh);
 873                 if (ret)
 874                         goto out;
 875
 876                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 877                      entry = EXT4_XATTR_NEXT(entry))
 878                         if (entry->e_value_inum)
 879                                 ea_inode_refs++;
 880         }
 881         *usage = ea_inode_refs + 1;
 882         ret = 0;
 883 out:
 884         brelse(iloc.bh);
 885         brelse(bh);
 886         return ret;
 887 }
 888
 889 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 890 {
 891         struct super_block *sb = inode->i_sb;
 892         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 893                                     inode->i_blkbits);
 894         size_t mask = ~(cluster_size - 1);
 895
 896         return (length + cluster_size - 1) & mask;
 897 }
 898
 899 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 900 {
 901         int err;
 902
 903         err = dquot_alloc_inode(inode);
 904         if (err)
 905                 return err;
 906         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 907         if (err)
 908                 dquot_free_inode(inode);
 909         return err;
 910 }
 911
 912 static void ext4_xattr_inode_free_quota(struct inode *parent,
 913                                         struct inode *ea_inode,
 914                                         size_t len)
 915 {
 916         if (ea_inode &&
 917             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 918                 return;
 919         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 920         dquot_free_inode(parent);
 921 }
 922
 923 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 924                              struct buffer_head *block_bh, size_t value_len,
 925                              bool is_create)
 926 {
 927         int credits;
 928         int blocks;
 929
 930         /*
 931          * 1) Owner inode update
 932          * 2) Ref count update on old xattr block
 933          * 3) new xattr block
 934          * 4) block bitmap update for new xattr block
 935          * 5) group descriptor for new xattr block
 936          * 6) block bitmap update for old xattr block
 937          * 7) group descriptor for old block
 938          *
 939          * 6 & 7 can happen if we have two racing threads T_a and T_b
 940          * which are each trying to set an xattr on inodes I_a and I_b
 941          * which were both initially sharing an xattr block.
 942          */
 943         credits = 7;
 944
 945         /* Quota updates. */
 946         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 947
 948         /*
 949          * In case of inline data, we may push out the data to a block,
 950          * so we need to reserve credits for this eventuality
 951          */
 952         if (inode && ext4_has_inline_data(inode))
 953                 credits += ext4_writepage_trans_blocks(inode) + 1;
 954
 955         /* We are done if ea_inode feature is not enabled. */
 956         if (!ext4_has_feature_ea_inode(sb))
 957                 return credits;
 958
 959         /* New ea_inode, inode map, block bitmap, group descriptor. */
 960         credits += 4;
 961
 962         /* Data blocks. */
 963         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 964
 965         /* Indirection block or one level of extent tree. */
 966         blocks += 1;
 967
 968         /* Block bitmap and group descriptor updates for each block. */
 969         credits += blocks * 2;
 970
 971         /* Blocks themselves. */
 972         credits += blocks;
 973
 974         if (!is_create) {
 975                 /* Dereference ea_inode holding old xattr value.
 976                  * Old ea_inode, inode map, block bitmap, group descriptor.
 977                  */
 978                 credits += 4;
 979
 980                 /* Data blocks for old ea_inode. */
 981                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 982
 983                 /* Indirection block or one level of extent tree for old
 984                  * ea_inode.
 985                  */
 986                 blocks += 1;
 987
 988                 /* Block bitmap and group descriptor updates for each block. */
 989                 credits += blocks * 2;
 990         }
 991
 992         /* We may need to clone the existing xattr block in which case we need
 993          * to increment ref counts for existing ea_inodes referenced by it.
 994          */
 995         if (block_bh) {
 996                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 997
 998                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 999                         if (entry->e_value_inum)
1000                                 /* Ref count update on ea_inode. */
1001                                 credits += 1;
1002         }
1003         return credits;
1004 }
1005
1006 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
1007                                        int ref_change)
1008 {
1009         struct ext4_iloc iloc;
1010         s64 ref_count;
1011         int ret;
1012
1013         inode_lock(ea_inode);
1014
1015         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1016         if (ret)
1017                 goto out;
1018
1019         ref_count = ext4_xattr_inode_get_ref(ea_inode);
1020         ref_count += ref_change;
1021         ext4_xattr_inode_set_ref(ea_inode, ref_count);
1022
1023         if (ref_change > 0) {
1024                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1025                           ea_inode->i_ino, ref_count);
1026
1027                 if (ref_count == 1) {
1028                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1029                                   ea_inode->i_ino, ea_inode->i_nlink);
1030
1031                         set_nlink(ea_inode, 1);
1032                         ext4_orphan_del(handle, ea_inode);
1033                 }
1034         } else {
1035                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1036                           ea_inode->i_ino, ref_count);
1037
1038                 if (ref_count == 0) {
1039                         WARN_ONCE(ea_inode->i_nlink != 1,
1040                                   "EA inode %lu i_nlink=%u",
1041                                   ea_inode->i_ino, ea_inode->i_nlink);
1042
1043                         clear_nlink(ea_inode);
1044                         ext4_orphan_add(handle, ea_inode);
1045                 }
1046         }
1047
1048         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1049         if (ret)
1050                 ext4_warning_inode(ea_inode,
1051                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1052 out:
1053         inode_unlock(ea_inode);
1054         return ret;
1055 }
1056
1057 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1058 {
1059         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1060 }
1061
1062 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1063 {
1064         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1065 }
1066
1067 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1068                                         struct ext4_xattr_entry *first)
1069 {
1070         struct inode *ea_inode;
1071         struct ext4_xattr_entry *entry;
1072         struct ext4_xattr_entry *failed_entry;
1073         unsigned int ea_ino;
1074         int err, saved_err;
1075
1076         for (entry = first; !IS_LAST_ENTRY(entry);
1077              entry = EXT4_XATTR_NEXT(entry)) {
1078                 if (!entry->e_value_inum)
1079                         continue;
1080                 ea_ino = le32_to_cpu(entry->e_value_inum);
1081                 err = ext4_xattr_inode_iget(parent, ea_ino,
1082                                             le32_to_cpu(entry->e_hash),
1083                                             &ea_inode);
1084                 if (err)
1085                         goto cleanup;
1086                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1087                 if (err) {
1088                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1089                         iput(ea_inode);
1090                         goto cleanup;
1091                 }
1092                 iput(ea_inode);
1093         }
1094         return 0;
1095
1096 cleanup:
1097         saved_err = err;
1098         failed_entry = entry;
1099
1100         for (entry = first; entry != failed_entry;
1101              entry = EXT4_XATTR_NEXT(entry)) {
1102                 if (!entry->e_value_inum)
1103                         continue;
1104                 ea_ino = le32_to_cpu(entry->e_value_inum);
1105                 err = ext4_xattr_inode_iget(parent, ea_ino,
1106                                             le32_to_cpu(entry->e_hash),
1107                                             &ea_inode);
1108                 if (err) {
1109                         ext4_warning(parent->i_sb,
1110                                      "cleanup ea_ino %u iget error %d", ea_ino,
1111                                      err);
1112                         continue;
1113                 }
1114                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1115                 if (err)
1116                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1117                                            err);
1118                 iput(ea_inode);
1119         }
1120         return saved_err;
1121 }
1122
1123 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1124                         struct buffer_head *bh, bool block_csum, bool dirty)
1125 {
1126         int error;
1127
1128         if (bh && dirty) {
1129                 if (block_csum)
1130                         ext4_xattr_block_csum_set(inode, bh);
1131                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1132                 if (error) {
1133                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1134                                      error);
1135                         return error;
1136                 }
1137         }
1138         return 0;
1139 }
1140
1141 static void
1142 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1143                              struct buffer_head *bh,
1144                              struct ext4_xattr_entry *first, bool block_csum,
1145                              struct ext4_xattr_inode_array **ea_inode_array,
1146                              int extra_credits, bool skip_quota)
1147 {
1148         struct inode *ea_inode;
1149         struct ext4_xattr_entry *entry;
1150         bool dirty = false;
1151         unsigned int ea_ino;
1152         int err;
1153         int credits;
1154
1155         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1156         credits = 2 + extra_credits;
1157
1158         for (entry = first; !IS_LAST_ENTRY(entry);
1159              entry = EXT4_XATTR_NEXT(entry)) {
1160                 if (!entry->e_value_inum)
1161                         continue;
1162                 ea_ino = le32_to_cpu(entry->e_value_inum);
1163                 err = ext4_xattr_inode_iget(parent, ea_ino,
1164                                             le32_to_cpu(entry->e_hash),
1165                                             &ea_inode);
1166                 if (err)
1167                         continue;
1168
1169                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1170                 if (err) {
1171                         ext4_warning_inode(ea_inode,
1172                                            "Expand inode array err=%d", err);
1173                         iput(ea_inode);
1174                         continue;
1175                 }
1176
1177                 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1178                         ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1179                         ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1180                                               dirty));
1181                 if (err < 0) {
1182                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1183                                            err);
1184                         continue;
1185                 }
1186                 if (err > 0) {
1187                         err = ext4_journal_get_write_access(handle,
1188                                         parent->i_sb, bh, EXT4_JTR_NONE);
1189                         if (err) {
1190                                 ext4_warning_inode(ea_inode,
1191                                                 "Re-get write access err=%d",
1192                                                 err);
1193                                 continue;
1194                         }
1195                 }
1196
1197                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1198                 if (err) {
1199                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1200                                            err);
1201                         continue;
1202                 }
1203
1204                 if (!skip_quota)
1205                         ext4_xattr_inode_free_quota(parent, ea_inode,
1206                                               le32_to_cpu(entry->e_value_size));
1207
1208                 /*
1209                  * Forget about ea_inode within the same transaction that
1210                  * decrements the ref count. This avoids duplicate decrements in
1211                  * case the rest of the work spills over to subsequent
1212                  * transactions.
1213                  */
1214                 entry->e_value_inum = 0;
1215                 entry->e_value_size = 0;
1216
1217                 dirty = true;
1218         }
1219
1220         if (dirty) {
1221                 /*
1222                  * Note that we are deliberately skipping csum calculation for
1223                  * the final update because we do not expect any journal
1224                  * restarts until xattr block is freed.
1225                  */
1226
1227                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1228                 if (err)
1229                         ext4_warning_inode(parent,
1230                                            "handle dirty metadata err=%d", err);
1231         }
1232 }
1233
1234 /*
1235  * Release the xattr block BH: If the reference count is > 1, decrement it;
1236  * otherwise free the block.
1237  */
1238 static void
1239 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1240                          struct buffer_head *bh,
1241                          struct ext4_xattr_inode_array **ea_inode_array,
1242                          int extra_credits)
1243 {
1244         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1245         u32 hash, ref;
1246         int error = 0;
1247
1248         BUFFER_TRACE(bh, "get_write_access");
1249         error = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1250                                               EXT4_JTR_NONE);
1251         if (error)
1252                 goto out;
1253
1254 retry_ref:
1255         lock_buffer(bh);
1256         hash = le32_to_cpu(BHDR(bh)->h_hash);
1257         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1258         if (ref == 1) {
1259                 ea_bdebug(bh, "refcount now=0; freeing");
1260                 /*
1261                  * This must happen under buffer lock for
1262                  * ext4_xattr_block_set() to reliably detect freed block
1263                  */
1264                 if (ea_block_cache) {
1265                         struct mb_cache_entry *oe;
1266
1267                         oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
1268                                                           bh->b_blocknr);
1269                         if (oe) {
1270                                 unlock_buffer(bh);
1271                                 mb_cache_entry_wait_unused(oe);
1272                                 mb_cache_entry_put(ea_block_cache, oe);
1273                                 goto retry_ref;
1274                         }
1275                 }
1276                 get_bh(bh);
1277                 unlock_buffer(bh);
1278
1279                 if (ext4_has_feature_ea_inode(inode->i_sb))
1280                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1281                                                      BFIRST(bh),
1282                                                      true /* block_csum */,
1283                                                      ea_inode_array,
1284                                                      extra_credits,
1285                                                      true /* skip_quota */);
1286                 ext4_free_blocks(handle, inode, bh, 0, 1,
1287                                  EXT4_FREE_BLOCKS_METADATA |
1288                                  EXT4_FREE_BLOCKS_FORGET);
1289         } else {
1290                 ref--;
1291                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1292                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1293                         struct mb_cache_entry *ce;
1294
1295                         if (ea_block_cache) {
1296                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1297                                                         bh->b_blocknr);
1298                                 if (ce) {
1299                                         set_bit(MBE_REUSABLE_B, &ce->e_flags);
1300                                         mb_cache_entry_put(ea_block_cache, ce);
1301                                 }
1302                         }
1303                 }
1304
1305                 ext4_xattr_block_csum_set(inode, bh);
1306                 /*
1307                  * Beware of this ugliness: Releasing of xattr block references
1308                  * from different inodes can race and so we have to protect
1309                  * from a race where someone else frees the block (and releases
1310                  * its journal_head) before we are done dirtying the buffer. In
1311                  * nojournal mode this race is harmless and we actually cannot
1312                  * call ext4_handle_dirty_metadata() with locked buffer as
1313                  * that function can call sync_dirty_buffer() so for that case
1314                  * we handle the dirtying after unlocking the buffer.
1315                  */
1316                 if (ext4_handle_valid(handle))
1317                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1318                 unlock_buffer(bh);
1319                 if (!ext4_handle_valid(handle))
1320                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1321                 if (IS_SYNC(inode))
1322                         ext4_handle_sync(handle);
1323                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1324                 ea_bdebug(bh, "refcount now=%d; releasing",
1325                           le32_to_cpu(BHDR(bh)->h_refcount));
1326         }
1327 out:
1328         ext4_std_error(inode->i_sb, error);
1329         return;
1330 }
1331
1332 /*
1333  * Find the available free space for EAs. This also returns the total number of
1334  * bytes used by EA entries.
1335  */
1336 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1337                                     size_t *min_offs, void *base, int *total)
1338 {
1339         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1340                 if (!last->e_value_inum && last->e_value_size) {
1341                         size_t offs = le16_to_cpu(last->e_value_offs);
1342                         if (offs < *min_offs)
1343                                 *min_offs = offs;
1344                 }
1345                 if (total)
1346                         *total += EXT4_XATTR_LEN(last->e_name_len);
1347         }
1348         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1349 }
1350
1351 /*
1352  * Write the value of the EA in an inode.
1353  */
1354 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1355                                   const void *buf, int bufsize)
1356 {
1357         struct buffer_head *bh = NULL;
1358         unsigned long block = 0;
1359         int blocksize = ea_inode->i_sb->s_blocksize;
1360         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1361         int csize, wsize = 0;
1362         int ret = 0, ret2 = 0;
1363         int retries = 0;
1364
1365 retry:
1366         while (ret >= 0 && ret < max_blocks) {
1367                 struct ext4_map_blocks map;
1368                 map.m_lblk = block += ret;
1369                 map.m_len = max_blocks -= ret;
1370
1371                 ret = ext4_map_blocks(handle, ea_inode, &map,
1372                                       EXT4_GET_BLOCKS_CREATE);
1373                 if (ret <= 0) {
1374                         ext4_mark_inode_dirty(handle, ea_inode);
1375                         if (ret == -ENOSPC &&
1376                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1377                                 ret = 0;
1378                                 goto retry;
1379                         }
1380                         break;
1381                 }
1382         }
1383
1384         if (ret < 0)
1385                 return ret;
1386
1387         block = 0;
1388         while (wsize < bufsize) {
1389                 brelse(bh);
1390                 csize = (bufsize - wsize) > blocksize ? blocksize :
1391                                                                 bufsize - wsize;
1392                 bh = ext4_getblk(handle, ea_inode, block, 0);
1393                 if (IS_ERR(bh))
1394                         return PTR_ERR(bh);
1395                 if (!bh) {
1396                         WARN_ON_ONCE(1);
1397                         EXT4_ERROR_INODE(ea_inode,
1398                                          "ext4_getblk() return bh = NULL");
1399                         return -EFSCORRUPTED;
1400                 }
1401                 ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh,
1402                                                    EXT4_JTR_NONE);
1403                 if (ret)
1404                         goto out;
1405
1406                 memcpy(bh->b_data, buf, csize);
1407                 set_buffer_uptodate(bh);
1408                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1409
1410                 buf += csize;
1411                 wsize += csize;
1412                 block += 1;
1413         }
1414
1415         inode_lock(ea_inode);
1416         i_size_write(ea_inode, wsize);
1417         ext4_update_i_disksize(ea_inode, wsize);
1418         inode_unlock(ea_inode);
1419
1420         ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1421         if (unlikely(ret2 && !ret))
1422                 ret = ret2;
1423
1424 out:
1425         brelse(bh);
1426
1427         return ret;
1428 }
1429
1430 /*
1431  * Create an inode to store the value of a large EA.
1432  */
1433 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1434                                              struct inode *inode, u32 hash)
1435 {
1436         struct inode *ea_inode = NULL;
1437         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1438         int err;
1439
1440         /*
1441          * Let the next inode be the goal, so we try and allocate the EA inode
1442          * in the same group, or nearby one.
1443          */
1444         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1445                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1446                                   EXT4_EA_INODE_FL);
1447         if (!IS_ERR(ea_inode)) {
1448                 ea_inode->i_op = &ext4_file_inode_operations;
1449                 ea_inode->i_fop = &ext4_file_operations;
1450                 ext4_set_aops(ea_inode);
1451                 ext4_xattr_inode_set_class(ea_inode);
1452                 unlock_new_inode(ea_inode);
1453                 ext4_xattr_inode_set_ref(ea_inode, 1);
1454                 ext4_xattr_inode_set_hash(ea_inode, hash);
1455                 err = ext4_mark_inode_dirty(handle, ea_inode);
1456                 if (!err)
1457                         err = ext4_inode_attach_jinode(ea_inode);
1458                 if (err) {
1459                         if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1460                                 ext4_warning_inode(ea_inode,
1461                                         "cleanup dec ref error %d", err);
1462                         iput(ea_inode);
1463                         return ERR_PTR(err);
1464                 }
1465
1466                 /*
1467                  * Xattr inodes are shared therefore quota charging is performed
1468                  * at a higher level.
1469                  */
1470                 dquot_free_inode(ea_inode);
1471                 dquot_drop(ea_inode);
1472                 inode_lock(ea_inode);
1473                 ea_inode->i_flags |= S_NOQUOTA;
1474                 inode_unlock(ea_inode);
1475         }
1476
1477         return ea_inode;
1478 }
1479
1480 static struct inode *
1481 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1482                             size_t value_len, u32 hash)
1483 {
1484         struct inode *ea_inode;
1485         struct mb_cache_entry *ce;
1486         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1487         void *ea_data;
1488
1489         if (!ea_inode_cache)
1490                 return NULL;
1491
1492         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1493         if (!ce)
1494                 return NULL;
1495
1496         WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1497                      !(current->flags & PF_MEMALLOC_NOFS));
1498
1499         ea_data = kvmalloc(value_len, GFP_KERNEL);
1500         if (!ea_data) {
1501                 mb_cache_entry_put(ea_inode_cache, ce);
1502                 return NULL;
1503         }
1504
1505         while (ce) {
1506                 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1507                                      EXT4_IGET_NORMAL);
1508                 if (!IS_ERR(ea_inode) &&
1509                     !is_bad_inode(ea_inode) &&
1510                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1511                     i_size_read(ea_inode) == value_len &&
1512                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1513                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1514                                                     value_len) &&
1515                     !memcmp(value, ea_data, value_len)) {
1516                         mb_cache_entry_touch(ea_inode_cache, ce);
1517                         mb_cache_entry_put(ea_inode_cache, ce);
1518                         kvfree(ea_data);
1519                         return ea_inode;
1520                 }
1521
1522                 if (!IS_ERR(ea_inode))
1523                         iput(ea_inode);
1524                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1525         }
1526         kvfree(ea_data);
1527         return NULL;
1528 }
1529
1530 /*
1531  * Add value of the EA in an inode.
1532  */
1533 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1534                                           const void *value, size_t value_len,
1535                                           struct inode **ret_inode)
1536 {
1537         struct inode *ea_inode;
1538         u32 hash;
1539         int err;
1540
1541         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1542         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1543         if (ea_inode) {
1544                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1545                 if (err) {
1546                         iput(ea_inode);
1547                         return err;
1548                 }
1549
1550                 *ret_inode = ea_inode;
1551                 return 0;
1552         }
1553
1554         /* Create an inode for the EA value */
1555         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1556         if (IS_ERR(ea_inode))
1557                 return PTR_ERR(ea_inode);
1558
1559         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1560         if (err) {
1561                 if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1562                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d", err);
1563                 iput(ea_inode);
1564                 return err;
1565         }
1566
1567         if (EA_INODE_CACHE(inode))
1568                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1569                                       ea_inode->i_ino, true /* reusable */);
1570
1571         *ret_inode = ea_inode;
1572         return 0;
1573 }
1574
1575 /*
1576  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1577  * feature is enabled.
1578  */
1579 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1580
1581 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1582                                 struct ext4_xattr_search *s,
1583                                 handle_t *handle, struct inode *inode,
1584                                 bool is_block)
1585 {
1586         struct ext4_xattr_entry *last, *next;
1587         struct ext4_xattr_entry *here = s->here;
1588         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1589         int in_inode = i->in_inode;
1590         struct inode *old_ea_inode = NULL;
1591         struct inode *new_ea_inode = NULL;
1592         size_t old_size, new_size;
1593         int ret;
1594
1595         /* Space used by old and new values. */
1596         old_size = (!s->not_found && !here->e_value_inum) ?
1597                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1598         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1599
1600         /*
1601          * Optimization for the simple case when old and new values have the
1602          * same padded sizes. Not applicable if external inodes are involved.
1603          */
1604         if (new_size && new_size == old_size) {
1605                 size_t offs = le16_to_cpu(here->e_value_offs);
1606                 void *val = s->base + offs;
1607
1608                 here->e_value_size = cpu_to_le32(i->value_len);
1609                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1610                         memset(val, 0, new_size);
1611                 } else {
1612                         memcpy(val, i->value, i->value_len);
1613                         /* Clear padding bytes. */
1614                         memset(val + i->value_len, 0, new_size - i->value_len);
1615                 }
1616                 goto update_hash;
1617         }
1618
1619         /* Compute min_offs and last. */
1620         last = s->first;
1621         for (; !IS_LAST_ENTRY(last); last = next) {
1622                 next = EXT4_XATTR_NEXT(last);
1623                 if ((void *)next >= s->end) {
1624                         EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1625                         ret = -EFSCORRUPTED;
1626                         goto out;
1627                 }
1628                 if (!last->e_value_inum && last->e_value_size) {
1629                         size_t offs = le16_to_cpu(last->e_value_offs);
1630                         if (offs < min_offs)
1631                                 min_offs = offs;
1632                 }
1633         }
1634
1635         /* Check whether we have enough space. */
1636         if (i->value) {
1637                 size_t free;
1638
1639                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1640                 if (!s->not_found)
1641                         free += EXT4_XATTR_LEN(name_len) + old_size;
1642
1643                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1644                         ret = -ENOSPC;
1645                         goto out;
1646                 }
1647
1648                 /*
1649                  * If storing the value in an external inode is an option,
1650                  * reserve space for xattr entries/names in the external
1651                  * attribute block so that a long value does not occupy the
1652                  * whole space and prevent further entries being added.
1653                  */
1654                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1655                     new_size && is_block &&
1656                     (min_offs + old_size - new_size) <
1657                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1658                         ret = -ENOSPC;
1659                         goto out;
1660                 }
1661         }
1662
1663         /*
1664          * Getting access to old and new ea inodes is subject to failures.
1665          * Finish that work before doing any modifications to the xattr data.
1666          */
1667         if (!s->not_found && here->e_value_inum) {
1668                 ret = ext4_xattr_inode_iget(inode,
1669                                             le32_to_cpu(here->e_value_inum),
1670                                             le32_to_cpu(here->e_hash),
1671                                             &old_ea_inode);
1672                 if (ret) {
1673                         old_ea_inode = NULL;
1674                         goto out;
1675                 }
1676         }
1677         if (i->value && in_inode) {
1678                 WARN_ON_ONCE(!i->value_len);
1679
1680                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1681                 if (ret)
1682                         goto out;
1683
1684                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1685                                                      i->value_len,
1686                                                      &new_ea_inode);
1687                 if (ret) {
1688                         new_ea_inode = NULL;
1689                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1690                         goto out;
1691                 }
1692         }
1693
1694         if (old_ea_inode) {
1695                 /* We are ready to release ref count on the old_ea_inode. */
1696                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1697                 if (ret) {
1698                         /* Release newly required ref count on new_ea_inode. */
1699                         if (new_ea_inode) {
1700                                 int err;
1701
1702                                 err = ext4_xattr_inode_dec_ref(handle,
1703                                                                new_ea_inode);
1704                                 if (err)
1705                                         ext4_warning_inode(new_ea_inode,
1706                                                   "dec ref new_ea_inode err=%d",
1707                                                   err);
1708                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1709                                                             i->value_len);
1710                         }
1711                         goto out;
1712                 }
1713
1714                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1715                                             le32_to_cpu(here->e_value_size));
1716         }
1717
1718         /* No failures allowed past this point. */
1719
1720         if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1721                 /* Remove the old value. */
1722                 void *first_val = s->base + min_offs;
1723                 size_t offs = le16_to_cpu(here->e_value_offs);
1724                 void *val = s->base + offs;
1725
1726                 memmove(first_val + old_size, first_val, val - first_val);
1727                 memset(first_val, 0, old_size);
1728                 min_offs += old_size;
1729
1730                 /* Adjust all value offsets. */
1731                 last = s->first;
1732                 while (!IS_LAST_ENTRY(last)) {
1733                         size_t o = le16_to_cpu(last->e_value_offs);
1734
1735                         if (!last->e_value_inum &&
1736                             last->e_value_size && o < offs)
1737                                 last->e_value_offs = cpu_to_le16(o + old_size);
1738                         last = EXT4_XATTR_NEXT(last);
1739                 }
1740         }
1741
1742         if (!i->value) {
1743                 /* Remove old name. */
1744                 size_t size = EXT4_XATTR_LEN(name_len);
1745
1746                 last = ENTRY((void *)last - size);
1747                 memmove(here, (void *)here + size,
1748                         (void *)last - (void *)here + sizeof(__u32));
1749                 memset(last, 0, size);
1750         } else if (s->not_found) {
1751                 /* Insert new name. */
1752                 size_t size = EXT4_XATTR_LEN(name_len);
1753                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1754
1755                 memmove((void *)here + size, here, rest);
1756                 memset(here, 0, size);
1757                 here->e_name_index = i->name_index;
1758                 here->e_name_len = name_len;
1759                 memcpy(here->e_name, i->name, name_len);
1760         } else {
1761                 /* This is an update, reset value info. */
1762                 here->e_value_inum = 0;
1763                 here->e_value_offs = 0;
1764                 here->e_value_size = 0;
1765         }
1766
1767         if (i->value) {
1768                 /* Insert new value. */
1769                 if (in_inode) {
1770                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1771                 } else if (i->value_len) {
1772                         void *val = s->base + min_offs - new_size;
1773
1774                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1775                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1776                                 memset(val, 0, new_size);
1777                         } else {
1778                                 memcpy(val, i->value, i->value_len);
1779                                 /* Clear padding bytes. */
1780                                 memset(val + i->value_len, 0,
1781                                        new_size - i->value_len);
1782                         }
1783                 }
1784                 here->e_value_size = cpu_to_le32(i->value_len);
1785         }
1786
1787 update_hash:
1788         if (i->value) {
1789                 __le32 hash = 0;
1790
1791                 /* Entry hash calculation. */
1792                 if (in_inode) {
1793                         __le32 crc32c_hash;
1794
1795                         /*
1796                          * Feed crc32c hash instead of the raw value for entry
1797                          * hash calculation. This is to avoid walking
1798                          * potentially long value buffer again.
1799                          */
1800                         crc32c_hash = cpu_to_le32(
1801                                        ext4_xattr_inode_get_hash(new_ea_inode));
1802                         hash = ext4_xattr_hash_entry(here->e_name,
1803                                                      here->e_name_len,
1804                                                      &crc32c_hash, 1);
1805                 } else if (is_block) {
1806                         __le32 *value = s->base + le16_to_cpu(
1807                                                         here->e_value_offs);
1808
1809                         hash = ext4_xattr_hash_entry(here->e_name,
1810                                                      here->e_name_len, value,
1811                                                      new_size >> 2);
1812                 }
1813                 here->e_hash = hash;
1814         }
1815
1816         if (is_block)
1817                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1818
1819         ret = 0;
1820 out:
1821         iput(old_ea_inode);
1822         iput(new_ea_inode);
1823         return ret;
1824 }
1825
1826 struct ext4_xattr_block_find {
1827         struct ext4_xattr_search s;
1828         struct buffer_head *bh;
1829 };
1830
1831 static int
1832 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1833                       struct ext4_xattr_block_find *bs)
1834 {
1835         struct super_block *sb = inode->i_sb;
1836         int error;
1837
1838         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1839                   i->name_index, i->name, i->value, (long)i->value_len);
1840
1841         if (EXT4_I(inode)->i_file_acl) {
1842                 /* The inode already has an extended attribute block. */
1843                 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1844                 if (IS_ERR(bs->bh)) {
1845                         error = PTR_ERR(bs->bh);
1846                         bs->bh = NULL;
1847                         return error;
1848                 }
1849                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1850                         atomic_read(&(bs->bh->b_count)),
1851                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1852                 error = ext4_xattr_check_block(inode, bs->bh);
1853                 if (error)
1854                         return error;
1855                 /* Find the named attribute. */
1856                 bs->s.base = BHDR(bs->bh);
1857                 bs->s.first = BFIRST(bs->bh);
1858                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1859                 bs->s.here = bs->s.first;
1860                 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1861                                          i->name_index, i->name, 1);
1862                 if (error && error != -ENODATA)
1863                         return error;
1864                 bs->s.not_found = error;
1865         }
1866         return 0;
1867 }
1868
1869 static int
1870 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1871                      struct ext4_xattr_info *i,
1872                      struct ext4_xattr_block_find *bs)
1873 {
1874         struct super_block *sb = inode->i_sb;
1875         struct buffer_head *new_bh = NULL;
1876         struct ext4_xattr_search s_copy = bs->s;
1877         struct ext4_xattr_search *s = &s_copy;
1878         struct mb_cache_entry *ce = NULL;
1879         int error = 0;
1880         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1881         struct inode *ea_inode = NULL, *tmp_inode;
1882         size_t old_ea_inode_quota = 0;
1883         unsigned int ea_ino;
1884
1885
1886 #define header(x) ((struct ext4_xattr_header *)(x))
1887
1888         if (s->base) {
1889                 int offset = (char *)s->here - bs->bh->b_data;
1890
1891                 BUFFER_TRACE(bs->bh, "get_write_access");
1892                 error = ext4_journal_get_write_access(handle, sb, bs->bh,
1893                                                       EXT4_JTR_NONE);
1894                 if (error)
1895                         goto cleanup;
1896                 lock_buffer(bs->bh);
1897
1898                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1899                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1900
1901                         /*
1902                          * This must happen under buffer lock for
1903                          * ext4_xattr_block_set() to reliably detect modified
1904                          * block
1905                          */
1906                         if (ea_block_cache) {
1907                                 struct mb_cache_entry *oe;
1908
1909                                 oe = mb_cache_entry_delete_or_get(ea_block_cache,
1910                                         hash, bs->bh->b_blocknr);
1911                                 if (oe) {
1912                                         /*
1913                                          * Xattr block is getting reused. Leave
1914                                          * it alone.
1915                                          */
1916                                         mb_cache_entry_put(ea_block_cache, oe);
1917                                         goto clone_block;
1918                                 }
1919                         }
1920                         ea_bdebug(bs->bh, "modifying in-place");
1921                         error = ext4_xattr_set_entry(i, s, handle, inode,
1922                                                      true /* is_block */);
1923                         ext4_xattr_block_csum_set(inode, bs->bh);
1924                         unlock_buffer(bs->bh);
1925                         if (error == -EFSCORRUPTED)
1926                                 goto bad_block;
1927                         if (!error)
1928                                 error = ext4_handle_dirty_metadata(handle,
1929                                                                    inode,
1930                                                                    bs->bh);
1931                         if (error)
1932                                 goto cleanup;
1933                         goto inserted;
1934                 }
1935 clone_block:
1936                 unlock_buffer(bs->bh);
1937                 ea_bdebug(bs->bh, "cloning");
1938                 s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
1939                 error = -ENOMEM;
1940                 if (s->base == NULL)
1941                         goto cleanup;
1942                 s->first = ENTRY(header(s->base)+1);
1943                 header(s->base)->h_refcount = cpu_to_le32(1);
1944                 s->here = ENTRY(s->base + offset);
1945                 s->end = s->base + bs->bh->b_size;
1946
1947                 /*
1948                  * If existing entry points to an xattr inode, we need
1949                  * to prevent ext4_xattr_set_entry() from decrementing
1950                  * ref count on it because the reference belongs to the
1951                  * original block. In this case, make the entry look
1952                  * like it has an empty value.
1953                  */
1954                 if (!s->not_found && s->here->e_value_inum) {
1955                         ea_ino = le32_to_cpu(s->here->e_value_inum);
1956                         error = ext4_xattr_inode_iget(inode, ea_ino,
1957                                       le32_to_cpu(s->here->e_hash),
1958                                       &tmp_inode);
1959                         if (error)
1960                                 goto cleanup;
1961
1962                         if (!ext4_test_inode_state(tmp_inode,
1963                                         EXT4_STATE_LUSTRE_EA_INODE)) {
1964                                 /*
1965                                  * Defer quota free call for previous
1966                                  * inode until success is guaranteed.
1967                                  */
1968                                 old_ea_inode_quota = le32_to_cpu(
1969                                                 s->here->e_value_size);
1970                         }
1971                         iput(tmp_inode);
1972
1973                         s->here->e_value_inum = 0;
1974                         s->here->e_value_size = 0;
1975                 }
1976         } else {
1977                 /* Allocate a buffer where we construct the new block. */
1978                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1979                 error = -ENOMEM;
1980                 if (s->base == NULL)
1981                         goto cleanup;
1982                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1983                 header(s->base)->h_blocks = cpu_to_le32(1);
1984                 header(s->base)->h_refcount = cpu_to_le32(1);
1985                 s->first = ENTRY(header(s->base)+1);
1986                 s->here = ENTRY(header(s->base)+1);
1987                 s->end = s->base + sb->s_blocksize;
1988         }
1989
1990         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1991         if (error == -EFSCORRUPTED)
1992                 goto bad_block;
1993         if (error)
1994                 goto cleanup;
1995
1996         if (i->value && s->here->e_value_inum) {
1997                 /*
1998                  * A ref count on ea_inode has been taken as part of the call to
1999                  * ext4_xattr_set_entry() above. We would like to drop this
2000                  * extra ref but we have to wait until the xattr block is
2001                  * initialized and has its own ref count on the ea_inode.
2002                  */
2003                 ea_ino = le32_to_cpu(s->here->e_value_inum);
2004                 error = ext4_xattr_inode_iget(inode, ea_ino,
2005                                               le32_to_cpu(s->here->e_hash),
2006                                               &ea_inode);
2007                 if (error) {
2008                         ea_inode = NULL;
2009                         goto cleanup;
2010                 }
2011         }
2012
2013 inserted:
2014         if (!IS_LAST_ENTRY(s->first)) {
2015                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
2016                                                      &ce);
2017                 if (new_bh) {
2018                         /* We found an identical block in the cache. */
2019                         if (new_bh == bs->bh)
2020                                 ea_bdebug(new_bh, "keeping");
2021                         else {
2022                                 u32 ref;
2023
2024                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
2025
2026                                 /* The old block is released after updating
2027                                    the inode. */
2028                                 error = dquot_alloc_block(inode,
2029                                                 EXT4_C2B(EXT4_SB(sb), 1));
2030                                 if (error)
2031                                         goto cleanup;
2032                                 BUFFER_TRACE(new_bh, "get_write_access");
2033                                 error = ext4_journal_get_write_access(
2034                                                 handle, sb, new_bh,
2035                                                 EXT4_JTR_NONE);
2036                                 if (error)
2037                                         goto cleanup_dquot;
2038                                 lock_buffer(new_bh);
2039                                 /*
2040                                  * We have to be careful about races with
2041                                  * adding references to xattr block. Once we
2042                                  * hold buffer lock xattr block's state is
2043                                  * stable so we can check the additional
2044                                  * reference fits.
2045                                  */
2046                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2047                                 if (ref > EXT4_XATTR_REFCOUNT_MAX) {
2048                                         /*
2049                                          * Undo everything and check mbcache
2050                                          * again.
2051                                          */
2052                                         unlock_buffer(new_bh);
2053                                         dquot_free_block(inode,
2054                                                          EXT4_C2B(EXT4_SB(sb),
2055                                                                   1));
2056                                         brelse(new_bh);
2057                                         mb_cache_entry_put(ea_block_cache, ce);
2058                                         ce = NULL;
2059                                         new_bh = NULL;
2060                                         goto inserted;
2061                                 }
2062                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2063                                 if (ref == EXT4_XATTR_REFCOUNT_MAX)
2064                                         clear_bit(MBE_REUSABLE_B, &ce->e_flags);
2065                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2066                                           ref);
2067                                 ext4_xattr_block_csum_set(inode, new_bh);
2068                                 unlock_buffer(new_bh);
2069                                 error = ext4_handle_dirty_metadata(handle,
2070                                                                    inode,
2071                                                                    new_bh);
2072                                 if (error)
2073                                         goto cleanup_dquot;
2074                         }
2075                         mb_cache_entry_touch(ea_block_cache, ce);
2076                         mb_cache_entry_put(ea_block_cache, ce);
2077                         ce = NULL;
2078                 } else if (bs->bh && s->base == bs->bh->b_data) {
2079                         /* We were modifying this block in-place. */
2080                         ea_bdebug(bs->bh, "keeping this block");
2081                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2082                         new_bh = bs->bh;
2083                         get_bh(new_bh);
2084                 } else {
2085                         /* We need to allocate a new block */
2086                         ext4_fsblk_t goal, block;
2087
2088                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2089
2090                         goal = ext4_group_first_block_no(sb,
2091                                                 EXT4_I(inode)->i_block_group);
2092                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2093                                                      NULL, &error);
2094                         if (error)
2095                                 goto cleanup;
2096
2097                         ea_idebug(inode, "creating block %llu",
2098                                   (unsigned long long)block);
2099
2100                         new_bh = sb_getblk(sb, block);
2101                         if (unlikely(!new_bh)) {
2102                                 error = -ENOMEM;
2103 getblk_failed:
2104                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2105                                                  EXT4_FREE_BLOCKS_METADATA);
2106                                 goto cleanup;
2107                         }
2108                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2109                                                       ENTRY(header(s->base)+1));
2110                         if (error)
2111                                 goto getblk_failed;
2112                         if (ea_inode) {
2113                                 /* Drop the extra ref on ea_inode. */
2114                                 error = ext4_xattr_inode_dec_ref(handle,
2115                                                                  ea_inode);
2116                                 if (error)
2117                                         ext4_warning_inode(ea_inode,
2118                                                            "dec ref error=%d",
2119                                                            error);
2120                                 iput(ea_inode);
2121                                 ea_inode = NULL;
2122                         }
2123
2124                         lock_buffer(new_bh);
2125                         error = ext4_journal_get_create_access(handle, sb,
2126                                                         new_bh, EXT4_JTR_NONE);
2127                         if (error) {
2128                                 unlock_buffer(new_bh);
2129                                 error = -EIO;
2130                                 goto getblk_failed;
2131                         }
2132                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2133                         ext4_xattr_block_csum_set(inode, new_bh);
2134                         set_buffer_uptodate(new_bh);
2135                         unlock_buffer(new_bh);
2136                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2137                         error = ext4_handle_dirty_metadata(handle, inode,
2138                                                            new_bh);
2139                         if (error)
2140                                 goto cleanup;
2141                 }
2142         }
2143
2144         if (old_ea_inode_quota)
2145                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2146
2147         /* Update the inode. */
2148         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2149
2150         /* Drop the previous xattr block. */
2151         if (bs->bh && bs->bh != new_bh) {
2152                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2153
2154                 ext4_xattr_release_block(handle, inode, bs->bh,
2155                                          &ea_inode_array,
2156                                          0 /* extra_credits */);
2157                 ext4_xattr_inode_array_free(ea_inode_array);
2158         }
2159         error = 0;
2160
2161 cleanup:
2162         if (ea_inode) {
2163                 int error2;
2164
2165                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2166                 if (error2)
2167                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2168                                            error2);
2169
2170                 /* If there was an error, revert the quota charge. */
2171                 if (error)
2172                         ext4_xattr_inode_free_quota(inode, ea_inode,
2173                                                     i_size_read(ea_inode));
2174                 iput(ea_inode);
2175         }
2176         if (ce)
2177                 mb_cache_entry_put(ea_block_cache, ce);
2178         brelse(new_bh);
2179         if (!(bs->bh && s->base == bs->bh->b_data))
2180                 kfree(s->base);
2181
2182         return error;
2183
2184 cleanup_dquot:
2185         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2186         goto cleanup;
2187
2188 bad_block:
2189         EXT4_ERROR_INODE(inode, "bad block %llu",
2190                          EXT4_I(inode)->i_file_acl);
2191         goto cleanup;
2192
2193 #undef header
2194 }
2195
2196 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2197                           struct ext4_xattr_ibody_find *is)
2198 {
2199         struct ext4_xattr_ibody_header *header;
2200         struct ext4_inode *raw_inode;
2201         int error;
2202
2203         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2204                 return 0;
2205
2206         raw_inode = ext4_raw_inode(&is->iloc);
2207         header = IHDR(inode, raw_inode);
2208         is->s.base = is->s.first = IFIRST(header);
2209         is->s.here = is->s.first;
2210         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2211         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2212                 error = xattr_check_inode(inode, header, is->s.end);
2213                 if (error)
2214                         return error;
2215                 /* Find the named attribute. */
2216                 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2217                                          i->name_index, i->name, 0);
2218                 if (error && error != -ENODATA)
2219                         return error;
2220                 is->s.not_found = error;
2221         }
2222         return 0;
2223 }
2224
2225 int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2226                                 struct ext4_xattr_info *i,
2227                                 struct ext4_xattr_ibody_find *is)
2228 {
2229         struct ext4_xattr_ibody_header *header;
2230         struct ext4_xattr_search *s = &is->s;
2231         int error;
2232
2233         if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2234                 return -ENOSPC;
2235
2236         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2237         if (error)
2238                 return error;
2239         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2240         if (!IS_LAST_ENTRY(s->first)) {
2241                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2242                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2243         } else {
2244                 header->h_magic = cpu_to_le32(0);
2245                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2246         }
2247         return 0;
2248 }
2249
2250 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2251                                  struct ext4_xattr_info *i)
2252 {
2253         void *value;
2254
2255         /* When e_value_inum is set the value is stored externally. */
2256         if (s->here->e_value_inum)
2257                 return 0;
2258         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2259                 return 0;
2260         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2261         return !memcmp(value, i->value, i->value_len);
2262 }
2263
2264 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2265 {
2266         struct buffer_head *bh;
2267         int error;
2268
2269         if (!EXT4_I(inode)->i_file_acl)
2270                 return NULL;
2271         bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2272         if (IS_ERR(bh))
2273                 return bh;
2274         error = ext4_xattr_check_block(inode, bh);
2275         if (error) {
2276                 brelse(bh);
2277                 return ERR_PTR(error);
2278         }
2279         return bh;
2280 }
2281
2282 /*
2283  * ext4_xattr_set_handle()
2284  *
2285  * Create, replace or remove an extended attribute for this inode.  Value
2286  * is NULL to remove an existing extended attribute, and non-NULL to
2287  * either replace an existing extended attribute, or create a new extended
2288  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2289  * specify that an extended attribute must exist and must not exist
2290  * previous to the call, respectively.
2291  *
2292  * Returns 0, or a negative error number on failure.
2293  */
2294 int
2295 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2296                       const char *name, const void *value, size_t value_len,
2297                       int flags)
2298 {
2299         struct ext4_xattr_info i = {
2300                 .name_index = name_index,
2301                 .name = name,
2302                 .value = value,
2303                 .value_len = value_len,
2304                 .in_inode = 0,
2305         };
2306         struct ext4_xattr_ibody_find is = {
2307                 .s = { .not_found = -ENODATA, },
2308         };
2309         struct ext4_xattr_block_find bs = {
2310                 .s = { .not_found = -ENODATA, },
2311         };
2312         int no_expand;
2313         int error;
2314
2315         if (!name)
2316                 return -EINVAL;
2317         if (strlen(name) > 255)
2318                 return -ERANGE;
2319
2320         ext4_write_lock_xattr(inode, &no_expand);
2321
2322         /* Check journal credits under write lock. */
2323         if (ext4_handle_valid(handle)) {
2324                 struct buffer_head *bh;
2325                 int credits;
2326
2327                 bh = ext4_xattr_get_block(inode);
2328                 if (IS_ERR(bh)) {
2329                         error = PTR_ERR(bh);
2330                         goto cleanup;
2331                 }
2332
2333                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2334                                                    value_len,
2335                                                    flags & XATTR_CREATE);
2336                 brelse(bh);
2337
2338                 if (jbd2_handle_buffer_credits(handle) < credits) {
2339                         error = -ENOSPC;
2340                         goto cleanup;
2341                 }
2342                 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2343         }
2344
2345         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2346         if (error)
2347                 goto cleanup;
2348
2349         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2350                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2351                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2352                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2353         }
2354
2355         error = ext4_xattr_ibody_find(inode, &i, &is);
2356         if (error)
2357                 goto cleanup;
2358         if (is.s.not_found)
2359                 error = ext4_xattr_block_find(inode, &i, &bs);
2360         if (error)
2361                 goto cleanup;
2362         if (is.s.not_found && bs.s.not_found) {
2363                 error = -ENODATA;
2364                 if (flags & XATTR_REPLACE)
2365                         goto cleanup;
2366                 error = 0;
2367                 if (!value)
2368                         goto cleanup;
2369         } else {
2370                 error = -EEXIST;
2371                 if (flags & XATTR_CREATE)
2372                         goto cleanup;
2373         }
2374
2375         if (!value) {
2376                 if (!is.s.not_found)
2377                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2378                 else if (!bs.s.not_found)
2379                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2380         } else {
2381                 error = 0;
2382                 /* Xattr value did not change? Save us some work and bail out */
2383                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2384                         goto cleanup;
2385                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2386                         goto cleanup;
2387
2388                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2389                     (EXT4_XATTR_SIZE(i.value_len) >
2390                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2391                         i.in_inode = 1;
2392 retry_inode:
2393                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2394                 if (!error && !bs.s.not_found) {
2395                         i.value = NULL;
2396                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2397                 } else if (error == -ENOSPC) {
2398                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2399                                 brelse(bs.bh);
2400                                 bs.bh = NULL;
2401                                 error = ext4_xattr_block_find(inode, &i, &bs);
2402                                 if (error)
2403                                         goto cleanup;
2404                         }
2405                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2406                         if (!error && !is.s.not_found) {
2407                                 i.value = NULL;
2408                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2409                                                              &is);
2410                         } else if (error == -ENOSPC) {
2411                                 /*
2412                                  * Xattr does not fit in the block, store at
2413                                  * external inode if possible.
2414                                  */
2415                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2416                                     i.value_len && !i.in_inode) {
2417                                         i.in_inode = 1;
2418                                         goto retry_inode;
2419                                 }
2420                         }
2421                 }
2422         }
2423         if (!error) {
2424                 ext4_xattr_update_super_block(handle, inode->i_sb);
2425                 inode->i_ctime = current_time(inode);
2426                 inode_inc_iversion(inode);
2427                 if (!value)
2428                         no_expand = 0;
2429                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2430                 /*
2431                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2432                  * error != 0.
2433                  */
2434                 is.iloc.bh = NULL;
2435                 if (IS_SYNC(inode))
2436                         ext4_handle_sync(handle);
2437         }
2438         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2439
2440 cleanup:
2441         brelse(is.iloc.bh);
2442         brelse(bs.bh);
2443         ext4_write_unlock_xattr(inode, &no_expand);
2444         return error;
2445 }
2446
2447 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2448                            bool is_create, int *credits)
2449 {
2450         struct buffer_head *bh;
2451         int err;
2452
2453         *credits = 0;
2454
2455         if (!EXT4_SB(inode->i_sb)->s_journal)
2456                 return 0;
2457
2458         down_read(&EXT4_I(inode)->xattr_sem);
2459
2460         bh = ext4_xattr_get_block(inode);
2461         if (IS_ERR(bh)) {
2462                 err = PTR_ERR(bh);
2463         } else {
2464                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2465                                                     value_len, is_create);
2466                 brelse(bh);
2467                 err = 0;
2468         }
2469
2470         up_read(&EXT4_I(inode)->xattr_sem);
2471         return err;
2472 }
2473
2474 /*
2475  * ext4_xattr_set()
2476  *
2477  * Like ext4_xattr_set_handle, but start from an inode. This extended
2478  * attribute modification is a filesystem transaction by itself.
2479  *
2480  * Returns 0, or a negative error number on failure.
2481  */
2482 int
2483 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2484                const void *value, size_t value_len, int flags)
2485 {
2486         handle_t *handle;
2487         struct super_block *sb = inode->i_sb;
2488         int error, retries = 0;
2489         int credits;
2490
2491         error = dquot_initialize(inode);
2492         if (error)
2493                 return error;
2494
2495 retry:
2496         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2497                                        &credits);
2498         if (error)
2499                 return error;
2500
2501         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2502         if (IS_ERR(handle)) {
2503                 error = PTR_ERR(handle);
2504         } else {
2505                 int error2;
2506
2507                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2508                                               value, value_len, flags);
2509                 error2 = ext4_journal_stop(handle);
2510                 if (error == -ENOSPC &&
2511                     ext4_should_retry_alloc(sb, &retries))
2512                         goto retry;
2513                 if (error == 0)
2514                         error = error2;
2515         }
2516         ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
2517
2518         return error;
2519 }
2520
2521 /*
2522  * Shift the EA entries in the inode to create space for the increased
2523  * i_extra_isize.
2524  */
2525 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2526                                      int value_offs_shift, void *to,
2527                                      void *from, size_t n)
2528 {
2529         struct ext4_xattr_entry *last = entry;
2530         int new_offs;
2531
2532         /* We always shift xattr headers further thus offsets get lower */
2533         BUG_ON(value_offs_shift > 0);
2534
2535         /* Adjust the value offsets of the entries */
2536         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2537                 if (!last->e_value_inum && last->e_value_size) {
2538                         new_offs = le16_to_cpu(last->e_value_offs) +
2539                                                         value_offs_shift;
2540                         last->e_value_offs = cpu_to_le16(new_offs);
2541                 }
2542         }
2543         /* Shift the entries by n bytes */
2544         memmove(to, from, n);
2545 }
2546
2547 /*
2548  * Move xattr pointed to by 'entry' from inode into external xattr block
2549  */
2550 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2551                                     struct ext4_inode *raw_inode,
2552                                     struct ext4_xattr_entry *entry)
2553 {
2554         struct ext4_xattr_ibody_find *is = NULL;
2555         struct ext4_xattr_block_find *bs = NULL;
2556         char *buffer = NULL, *b_entry_name = NULL;
2557         size_t value_size = le32_to_cpu(entry->e_value_size);
2558         struct ext4_xattr_info i = {
2559                 .value = NULL,
2560                 .value_len = 0,
2561                 .name_index = entry->e_name_index,
2562                 .in_inode = !!entry->e_value_inum,
2563         };
2564         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2565         int error;
2566
2567         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2568         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2569         buffer = kvmalloc(value_size, GFP_NOFS);
2570         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2571         if (!is || !bs || !buffer || !b_entry_name) {
2572                 error = -ENOMEM;
2573                 goto out;
2574         }
2575
2576         is->s.not_found = -ENODATA;
2577         bs->s.not_found = -ENODATA;
2578         is->iloc.bh = NULL;
2579         bs->bh = NULL;
2580
2581         /* Save the entry name and the entry value */
2582         if (entry->e_value_inum) {
2583                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2584                 if (error)
2585                         goto out;
2586         } else {
2587                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2588                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2589         }
2590
2591         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2592         b_entry_name[entry->e_name_len] = '\0';
2593         i.name = b_entry_name;
2594
2595         error = ext4_get_inode_loc(inode, &is->iloc);
2596         if (error)
2597                 goto out;
2598
2599         error = ext4_xattr_ibody_find(inode, &i, is);
2600         if (error)
2601                 goto out;
2602
2603         /* Remove the chosen entry from the inode */
2604         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2605         if (error)
2606                 goto out;
2607
2608         i.value = buffer;
2609         i.value_len = value_size;
2610         error = ext4_xattr_block_find(inode, &i, bs);
2611         if (error)
2612                 goto out;
2613
2614         /* Add entry which was removed from the inode into the block */
2615         error = ext4_xattr_block_set(handle, inode, &i, bs);
2616         if (error)
2617                 goto out;
2618         error = 0;
2619 out:
2620         kfree(b_entry_name);
2621         kvfree(buffer);
2622         if (is)
2623                 brelse(is->iloc.bh);
2624         if (bs)
2625                 brelse(bs->bh);
2626         kfree(is);
2627         kfree(bs);
2628
2629         return error;
2630 }
2631
2632 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2633                                        struct ext4_inode *raw_inode,
2634                                        int isize_diff, size_t ifree,
2635                                        size_t bfree, int *total_ino)
2636 {
2637         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2638         struct ext4_xattr_entry *small_entry;
2639         struct ext4_xattr_entry *entry;
2640         struct ext4_xattr_entry *last;
2641         unsigned int entry_size;        /* EA entry size */
2642         unsigned int total_size;        /* EA entry size + value size */
2643         unsigned int min_total_size;
2644         int error;
2645
2646         while (isize_diff > ifree) {
2647                 entry = NULL;
2648                 small_entry = NULL;
2649                 min_total_size = ~0U;
2650                 last = IFIRST(header);
2651                 /* Find the entry best suited to be pushed into EA block */
2652                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2653                         /* never move system.data out of the inode */
2654                         if ((last->e_name_len == 4) &&
2655                             (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2656                             !memcmp(last->e_name, "data", 4))
2657                                 continue;
2658                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2659                         if (!last->e_value_inum)
2660                                 total_size += EXT4_XATTR_SIZE(
2661                                                le32_to_cpu(last->e_value_size));
2662                         if (total_size <= bfree &&
2663                             total_size < min_total_size) {
2664                                 if (total_size + ifree < isize_diff) {
2665                                         small_entry = last;
2666                                 } else {
2667                                         entry = last;
2668                                         min_total_size = total_size;
2669                                 }
2670                         }
2671                 }
2672
2673                 if (entry == NULL) {
2674                         if (small_entry == NULL)
2675                                 return -ENOSPC;
2676                         entry = small_entry;
2677                 }
2678
2679                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2680                 total_size = entry_size;
2681                 if (!entry->e_value_inum)
2682                         total_size += EXT4_XATTR_SIZE(
2683                                               le32_to_cpu(entry->e_value_size));
2684                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2685                                                  entry);
2686                 if (error)
2687                         return error;
2688
2689                 *total_ino -= entry_size;
2690                 ifree += total_size;
2691                 bfree -= total_size;
2692         }
2693
2694         return 0;
2695 }
2696
2697 /*
2698  * Expand an inode by new_extra_isize bytes when EAs are present.
2699  * Returns 0 on success or negative error number on failure.
2700  */
2701 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2702                                struct ext4_inode *raw_inode, handle_t *handle)
2703 {
2704         struct ext4_xattr_ibody_header *header;
2705         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2706         static unsigned int mnt_count;
2707         size_t min_offs;
2708         size_t ifree, bfree;
2709         int total_ino;
2710         void *base, *end;
2711         int error = 0, tried_min_extra_isize = 0;
2712         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2713         int isize_diff; /* How much do we need to grow i_extra_isize */
2714
2715 retry:
2716         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2717         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2718                 return 0;
2719
2720         header = IHDR(inode, raw_inode);
2721
2722         /*
2723          * Check if enough free space is available in the inode to shift the
2724          * entries ahead by new_extra_isize.
2725          */
2726
2727         base = IFIRST(header);
2728         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2729         min_offs = end - base;
2730         total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2731
2732         error = xattr_check_inode(inode, header, end);
2733         if (error)
2734                 goto cleanup;
2735
2736         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2737         if (ifree >= isize_diff)
2738                 goto shift;
2739
2740         /*
2741          * Enough free space isn't available in the inode, check if
2742          * EA block can hold new_extra_isize bytes.
2743          */
2744         if (EXT4_I(inode)->i_file_acl) {
2745                 struct buffer_head *bh;
2746
2747                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2748                 if (IS_ERR(bh)) {
2749                         error = PTR_ERR(bh);
2750                         goto cleanup;
2751                 }
2752                 error = ext4_xattr_check_block(inode, bh);
2753                 if (error) {
2754                         brelse(bh);
2755                         goto cleanup;
2756                 }
2757                 base = BHDR(bh);
2758                 end = bh->b_data + bh->b_size;
2759                 min_offs = end - base;
2760                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2761                                               NULL);
2762                 brelse(bh);
2763                 if (bfree + ifree < isize_diff) {
2764                         if (!tried_min_extra_isize && s_min_extra_isize) {
2765                                 tried_min_extra_isize++;
2766                                 new_extra_isize = s_min_extra_isize;
2767                                 goto retry;
2768                         }
2769                         error = -ENOSPC;
2770                         goto cleanup;
2771                 }
2772         } else {
2773                 bfree = inode->i_sb->s_blocksize;
2774         }
2775
2776         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2777                                             isize_diff, ifree, bfree,
2778                                             &total_ino);
2779         if (error) {
2780                 if (error == -ENOSPC && !tried_min_extra_isize &&
2781                     s_min_extra_isize) {
2782                         tried_min_extra_isize++;
2783                         new_extra_isize = s_min_extra_isize;
2784                         goto retry;
2785                 }
2786                 goto cleanup;
2787         }
2788 shift:
2789         /* Adjust the offsets and shift the remaining entries ahead */
2790         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2791                         - new_extra_isize, (void *)raw_inode +
2792                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2793                         (void *)header, total_ino);
2794         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2795
2796 cleanup:
2797         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2798                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2799                              inode->i_ino);
2800                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2801         }
2802         return error;
2803 }
2804
2805 #define EIA_INCR 16 /* must be 2^n */
2806 #define EIA_MASK (EIA_INCR - 1)
2807
2808 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2809  * If @ea_inode_array is new or full it will be grown and the old
2810  * contents copied over.
2811  */
2812 static int
2813 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2814                         struct inode *inode)
2815 {
2816         if (*ea_inode_array == NULL) {
2817                 /*
2818                  * Start with 15 inodes, so it fits into a power-of-two size.
2819                  * If *ea_inode_array is NULL, this is essentially offsetof()
2820                  */
2821                 (*ea_inode_array) =
2822                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2823                                          inodes[EIA_MASK]),
2824                                 GFP_NOFS);
2825                 if (*ea_inode_array == NULL)
2826                         return -ENOMEM;
2827                 (*ea_inode_array)->count = 0;
2828         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2829                 /* expand the array once all 15 + n * 16 slots are full */
2830                 struct ext4_xattr_inode_array *new_array = NULL;
2831                 int count = (*ea_inode_array)->count;
2832
2833                 /* if new_array is NULL, this is essentially offsetof() */
2834                 new_array = kmalloc(
2835                                 offsetof(struct ext4_xattr_inode_array,
2836                                          inodes[count + EIA_INCR]),
2837                                 GFP_NOFS);
2838                 if (new_array == NULL)
2839                         return -ENOMEM;
2840                 memcpy(new_array, *ea_inode_array,
2841                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2842                 kfree(*ea_inode_array);
2843                 *ea_inode_array = new_array;
2844         }
2845         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2846         return 0;
2847 }
2848
2849 /*
2850  * ext4_xattr_delete_inode()
2851  *
2852  * Free extended attribute resources associated with this inode. Traverse
2853  * all entries and decrement reference on any xattr inodes associated with this
2854  * inode. This is called immediately before an inode is freed. We have exclusive
2855  * access to the inode. If an orphan inode is deleted it will also release its
2856  * references on xattr block and xattr inodes.
2857  */
2858 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2859                             struct ext4_xattr_inode_array **ea_inode_array,
2860                             int extra_credits)
2861 {
2862         struct buffer_head *bh = NULL;
2863         struct ext4_xattr_ibody_header *header;
2864         struct ext4_iloc iloc = { .bh = NULL };
2865         struct ext4_xattr_entry *entry;
2866         struct inode *ea_inode;
2867         int error;
2868
2869         error = ext4_journal_ensure_credits(handle, extra_credits,
2870                         ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2871         if (error < 0) {
2872                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2873                 goto cleanup;
2874         }
2875
2876         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2877             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2878
2879                 error = ext4_get_inode_loc(inode, &iloc);
2880                 if (error) {
2881                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2882                         goto cleanup;
2883                 }
2884
2885                 error = ext4_journal_get_write_access(handle, inode->i_sb,
2886                                                 iloc.bh, EXT4_JTR_NONE);
2887                 if (error) {
2888                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2889                                          error);
2890                         goto cleanup;
2891                 }
2892
2893                 header = IHDR(inode, ext4_raw_inode(&iloc));
2894                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2895                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2896                                                      IFIRST(header),
2897                                                      false /* block_csum */,
2898                                                      ea_inode_array,
2899                                                      extra_credits,
2900                                                      false /* skip_quota */);
2901         }
2902
2903         if (EXT4_I(inode)->i_file_acl) {
2904                 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2905                 if (IS_ERR(bh)) {
2906                         error = PTR_ERR(bh);
2907                         if (error == -EIO) {
2908                                 EXT4_ERROR_INODE_ERR(inode, EIO,
2909                                                      "block %llu read error",
2910                                                      EXT4_I(inode)->i_file_acl);
2911                         }
2912                         bh = NULL;
2913                         goto cleanup;
2914                 }
2915                 error = ext4_xattr_check_block(inode, bh);
2916                 if (error)
2917                         goto cleanup;
2918
2919                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2920                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2921                              entry = EXT4_XATTR_NEXT(entry)) {
2922                                 if (!entry->e_value_inum)
2923                                         continue;
2924                                 error = ext4_xattr_inode_iget(inode,
2925                                               le32_to_cpu(entry->e_value_inum),
2926                                               le32_to_cpu(entry->e_hash),
2927                                               &ea_inode);
2928                                 if (error)
2929                                         continue;
2930                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2931                                               le32_to_cpu(entry->e_value_size));
2932                                 iput(ea_inode);
2933                         }
2934
2935                 }
2936
2937                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2938                                          extra_credits);
2939                 /*
2940                  * Update i_file_acl value in the same transaction that releases
2941                  * block.
2942                  */
2943                 EXT4_I(inode)->i_file_acl = 0;
2944                 error = ext4_mark_inode_dirty(handle, inode);
2945                 if (error) {
2946                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2947                                          error);
2948                         goto cleanup;
2949                 }
2950                 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2951         }
2952         error = 0;
2953 cleanup:
2954         brelse(iloc.bh);
2955         brelse(bh);
2956         return error;
2957 }
2958
2959 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2960 {
2961         int idx;
2962
2963         if (ea_inode_array == NULL)
2964                 return;
2965
2966         for (idx = 0; idx < ea_inode_array->count; ++idx)
2967                 iput(ea_inode_array->inodes[idx]);
2968         kfree(ea_inode_array);
2969 }
2970
2971 /*
2972  * ext4_xattr_block_cache_insert()
2973  *
2974  * Create a new entry in the extended attribute block cache, and insert
2975  * it unless such an entry is already in the cache.
2976  *
2977  * Returns 0, or a negative error number on failure.
2978  */
2979 static void
2980 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2981                               struct buffer_head *bh)
2982 {
2983         struct ext4_xattr_header *header = BHDR(bh);
2984         __u32 hash = le32_to_cpu(header->h_hash);
2985         int reusable = le32_to_cpu(header->h_refcount) <
2986                        EXT4_XATTR_REFCOUNT_MAX;
2987         int error;
2988
2989         if (!ea_block_cache)
2990                 return;
2991         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2992                                       bh->b_blocknr, reusable);
2993         if (error) {
2994                 if (error == -EBUSY)
2995                         ea_bdebug(bh, "already in cache");
2996         } else
2997                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2998 }
2999
3000 /*
3001  * ext4_xattr_cmp()
3002  *
3003  * Compare two extended attribute blocks for equality.
3004  *
3005  * Returns 0 if the blocks are equal, 1 if they differ, and
3006  * a negative error number on errors.
3007  */
3008 static int
3009 ext4_xattr_cmp(struct ext4_xattr_header *header1,
3010                struct ext4_xattr_header *header2)
3011 {
3012         struct ext4_xattr_entry *entry1, *entry2;
3013
3014         entry1 = ENTRY(header1+1);
3015         entry2 = ENTRY(header2+1);
3016         while (!IS_LAST_ENTRY(entry1)) {
3017                 if (IS_LAST_ENTRY(entry2))
3018                         return 1;
3019                 if (entry1->e_hash != entry2->e_hash ||
3020                     entry1->e_name_index != entry2->e_name_index ||
3021                     entry1->e_name_len != entry2->e_name_len ||
3022                     entry1->e_value_size != entry2->e_value_size ||
3023                     entry1->e_value_inum != entry2->e_value_inum ||
3024                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3025                         return 1;
3026                 if (!entry1->e_value_inum &&
3027                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3028                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3029                            le32_to_cpu(entry1->e_value_size)))
3030                         return 1;
3031
3032                 entry1 = EXT4_XATTR_NEXT(entry1);
3033                 entry2 = EXT4_XATTR_NEXT(entry2);
3034         }
3035         if (!IS_LAST_ENTRY(entry2))
3036                 return 1;
3037         return 0;
3038 }
3039
3040 /*
3041  * ext4_xattr_block_cache_find()
3042  *
3043  * Find an identical extended attribute block.
3044  *
3045  * Returns a pointer to the block found, or NULL if such a block was
3046  * not found or an error occurred.
3047  */
3048 static struct buffer_head *
3049 ext4_xattr_block_cache_find(struct inode *inode,
3050                             struct ext4_xattr_header *header,
3051                             struct mb_cache_entry **pce)
3052 {
3053         __u32 hash = le32_to_cpu(header->h_hash);
3054         struct mb_cache_entry *ce;
3055         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3056
3057         if (!ea_block_cache)
3058                 return NULL;
3059         if (!header->h_hash)
3060                 return NULL;  /* never share */
3061         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3062         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3063         while (ce) {
3064                 struct buffer_head *bh;
3065
3066                 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3067                 if (IS_ERR(bh)) {
3068                         if (PTR_ERR(bh) == -ENOMEM)
3069                                 return NULL;
3070                         bh = NULL;
3071                         EXT4_ERROR_INODE(inode, "block %lu read error",
3072                                          (unsigned long)ce->e_value);
3073                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3074                         *pce = ce;
3075                         return bh;
3076                 }
3077                 brelse(bh);
3078                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3079         }
3080         return NULL;
3081 }
3082
3083 #define NAME_HASH_SHIFT 5
3084 #define VALUE_HASH_SHIFT 16
3085
3086 /*
3087  * ext4_xattr_hash_entry()
3088  *
3089  * Compute the hash of an extended attribute.
3090  */
3091 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3092                                     size_t value_count)
3093 {
3094         __u32 hash = 0;
3095
3096         while (name_len--) {
3097                 hash = (hash << NAME_HASH_SHIFT) ^
3098                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3099                        *name++;
3100         }
3101         while (value_count--) {
3102                 hash = (hash << VALUE_HASH_SHIFT) ^
3103                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3104                        le32_to_cpu(*value++);
3105         }
3106         return cpu_to_le32(hash);
3107 }
3108
3109 /*
3110  * ext4_xattr_hash_entry_signed()
3111  *
3112  * Compute the hash of an extended attribute incorrectly.
3113  */
3114 static __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value, size_t value_count)
3115 {
3116         __u32 hash = 0;
3117
3118         while (name_len--) {
3119                 hash = (hash << NAME_HASH_SHIFT) ^
3120                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3121                        (signed char)*name++;
3122         }
3123         while (value_count--) {
3124                 hash = (hash << VALUE_HASH_SHIFT) ^
3125                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3126                        le32_to_cpu(*value++);
3127         }
3128         return cpu_to_le32(hash);
3129 }
3130
3131 #undef NAME_HASH_SHIFT
3132 #undef VALUE_HASH_SHIFT
3133
3134 #define BLOCK_HASH_SHIFT 16
3135
3136 /*
3137  * ext4_xattr_rehash()
3138  *
3139  * Re-compute the extended attribute hash value after an entry has changed.
3140  */
3141 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3142 {
3143         struct ext4_xattr_entry *here;
3144         __u32 hash = 0;
3145
3146         here = ENTRY(header+1);
3147         while (!IS_LAST_ENTRY(here)) {
3148                 if (!here->e_hash) {
3149                         /* Block is not shared if an entry's hash value == 0 */
3150                         hash = 0;
3151                         break;
3152                 }
3153                 hash = (hash << BLOCK_HASH_SHIFT) ^
3154                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3155                        le32_to_cpu(here->e_hash);
3156                 here = EXT4_XATTR_NEXT(here);
3157         }
3158         header->h_hash = cpu_to_le32(hash);
3159 }
3160
3161 #undef BLOCK_HASH_SHIFT
3162
3163 #define HASH_BUCKET_BITS        10
3164
3165 struct mb_cache *
3166 ext4_xattr_create_cache(void)
3167 {
3168         return mb_cache_create(HASH_BUCKET_BITS);
3169 }
3170
3171 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3172 {
3173         if (cache)
3174                 mb_cache_destroy(cache);
3175 }
3176