fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
   5  *
   6  * Fix by Harrison Xing <[email protected]>.
   7  * Ext4 code with a lot of help from Eric Jarman <[email protected]>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <[email protected]>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <[email protected]>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <[email protected]> aka bzzz
  13  *  and Andreas Gruenbacher <[email protected]>.
  14  */
  15
  16 /*
  17  * Extended attributes are stored directly in inodes (on file systems with
  18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19  * field contains the block number if an inode uses an additional block. All
  20  * attributes must fit in the inode and one additional block. Blocks that
  21  * contain the identical set of attributes may be shared among several inodes.
  22  * Identical blocks are detected by keeping a cache of blocks that have
  23  * recently been accessed.
  24  *
  25  * The attributes in inodes and on blocks have a different header; the entries
  26  * are stored in the same format:
  27  *
  28  *   +------------------+
  29  *   | header           |
  30  *   | entry 1          | |
  31  *   | entry 2          | | growing downwards
  32  *   | entry 3          | v
  33  *   | four null bytes  |
  34  *   | . . .            |
  35  *   | value 1          | ^
  36  *   | value 3          | | growing upwards
  37  *   | value 2          | |
  38  *   +------------------+
  39  *
  40  * The header is followed by multiple entry descriptors. In disk blocks, the
  41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42  * attribute values are aligned to the end of the block in no specific order.
  43  *
  44  * Locking strategy
  45  * ----------------
  46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47  * EA blocks are only changed if they are exclusive to an inode, so
  48  * holding xattr_sem also means that nothing but the EA block's reference
  49  * count can change. Multiple writers to the same block are synchronized
  50  * by the buffer lock.
  51  */
  52
  53 #include <linux/init.h>
  54 #include <linux/fs.h>
  55 #include <linux/slab.h>
  56 #include <linux/mbcache.h>
  57 #include <linux/quotaops.h>
  58 #include "ext4_jbd2.h"
  59 #include "ext4.h"
  60 #include "xattr.h"
  61 #include "acl.h"
  62
  63 #ifdef EXT4_XATTR_DEBUG
  64 # define ea_idebug(inode, fmt, ...)                                     \
  65         printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",                    \
  66                inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
  67 # define ea_bdebug(bh, fmt, ...)                                        \
  68         printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",                   \
  69                bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
  70 #else
  71 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  72 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  73 #endif
  74
  75 static void ext4_xattr_block_cache_insert(struct mb_cache *,
  76                                           struct buffer_head *);
  77 static struct buffer_head *
  78 ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
  79                             struct mb_cache_entry **);
  80 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
  81                                     size_t value_count);
  82 static void ext4_xattr_rehash(struct ext4_xattr_header *);
  83
  84 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
  85         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  86 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  87         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  88         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  89 #endif
  90         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
  91 #ifdef CONFIG_EXT4_FS_SECURITY
  92         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
  93 #endif
  94 };
  95
  96 const struct xattr_handler *ext4_xattr_handlers[] = {
  97         &ext4_xattr_user_handler,
  98         &ext4_xattr_trusted_handler,
  99 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 100         &posix_acl_access_xattr_handler,
 101         &posix_acl_default_xattr_handler,
 102 #endif
 103 #ifdef CONFIG_EXT4_FS_SECURITY
 104         &ext4_xattr_security_handler,
 105 #endif
 106         NULL
 107 };
 108
 109 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 110                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 111
 112 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 113                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 114
 115 static int
 116 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 117                         struct inode *inode);
 118
 119 #ifdef CONFIG_LOCKDEP
 120 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 121 {
 122         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 123 }
 124 #endif
 125
 126 static __le32 ext4_xattr_block_csum(struct inode *inode,
 127                                     sector_t block_nr,
 128                                     struct ext4_xattr_header *hdr)
 129 {
 130         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 131         __u32 csum;
 132         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 133         __u32 dummy_csum = 0;
 134         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 135
 136         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 137                            sizeof(dsk_block_nr));
 138         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 139         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 140         offset += sizeof(dummy_csum);
 141         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 142                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 143
 144         return cpu_to_le32(csum);
 145 }
 146
 147 static int ext4_xattr_block_csum_verify(struct inode *inode,
 148                                         struct buffer_head *bh)
 149 {
 150         struct ext4_xattr_header *hdr = BHDR(bh);
 151         int ret = 1;
 152
 153         if (ext4_has_metadata_csum(inode->i_sb)) {
 154                 lock_buffer(bh);
 155                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 156                                                         bh->b_blocknr, hdr));
 157                 unlock_buffer(bh);
 158         }
 159         return ret;
 160 }
 161
 162 static void ext4_xattr_block_csum_set(struct inode *inode,
 163                                       struct buffer_head *bh)
 164 {
 165         if (ext4_has_metadata_csum(inode->i_sb))
 166                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 167                                                 bh->b_blocknr, BHDR(bh));
 168 }
 169
 170 static inline const struct xattr_handler *
 171 ext4_xattr_handler(int name_index)
 172 {
 173         const struct xattr_handler *handler = NULL;
 174
 175         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 176                 handler = ext4_xattr_handler_map[name_index];
 177         return handler;
 178 }
 179
 180 static int
 181 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
 182                          void *value_start)
 183 {
 184         struct ext4_xattr_entry *e = entry;
 185
 186         /* Find the end of the names list */
 187         while (!IS_LAST_ENTRY(e)) {
 188                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 189                 if ((void *)next >= end)
 190                         return -EFSCORRUPTED;
 191                 e = next;
 192         }
 193
 194         /* Check the values */
 195         while (!IS_LAST_ENTRY(entry)) {
 196                 if (entry->e_value_size != 0 &&
 197                     entry->e_value_inum == 0) {
 198                         u16 offs = le16_to_cpu(entry->e_value_offs);
 199                         u32 size = le32_to_cpu(entry->e_value_size);
 200                         void *value;
 201
 202                         /*
 203                          * The value cannot overlap the names, and the value
 204                          * with padding cannot extend beyond 'end'.  Check both
 205                          * the padded and unpadded sizes, since the size may
 206                          * overflow to 0 when adding padding.
 207                          */
 208                         if (offs > end - value_start)
 209                                 return -EFSCORRUPTED;
 210                         value = value_start + offs;
 211                         if (value < (void *)e + sizeof(u32) ||
 212                             size > end - value ||
 213                             EXT4_XATTR_SIZE(size) > end - value)
 214                                 return -EFSCORRUPTED;
 215                 }
 216                 entry = EXT4_XATTR_NEXT(entry);
 217         }
 218
 219         return 0;
 220 }
 221
 222 static inline int
 223 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 224 {
 225         int error;
 226
 227         if (buffer_verified(bh))
 228                 return 0;
 229
 230         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 231             BHDR(bh)->h_blocks != cpu_to_le32(1))
 232                 return -EFSCORRUPTED;
 233         if (!ext4_xattr_block_csum_verify(inode, bh))
 234                 return -EFSBADCRC;
 235         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 236                                          bh->b_data);
 237         if (!error)
 238                 set_buffer_verified(bh);
 239         return error;
 240 }
 241
 242 static int
 243 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 244                          void *end, const char *function, unsigned int line)
 245 {
 246         int error = -EFSCORRUPTED;
 247
 248         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 249             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 250                 goto errout;
 251         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 252 errout:
 253         if (error)
 254                 __ext4_error_inode(inode, function, line, 0,
 255                                    "corrupted in-inode xattr");
 256         return error;
 257 }
 258
 259 #define xattr_check_inode(inode, header, end) \
 260         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 261
 262 static int
 263 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 264                       const char *name, int sorted)
 265 {
 266         struct ext4_xattr_entry *entry;
 267         size_t name_len;
 268         int cmp = 1;
 269
 270         if (name == NULL)
 271                 return -EINVAL;
 272         name_len = strlen(name);
 273         entry = *pentry;
 274         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 275                 cmp = name_index - entry->e_name_index;
 276                 if (!cmp)
 277                         cmp = name_len - entry->e_name_len;
 278                 if (!cmp)
 279                         cmp = memcmp(name, entry->e_name, name_len);
 280                 if (cmp <= 0 && (sorted || cmp == 0))
 281                         break;
 282         }
 283         *pentry = entry;
 284         return cmp ? -ENODATA : 0;
 285 }
 286
 287 static u32
 288 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 289 {
 290         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 291 }
 292
 293 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 294 {
 295         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 296                ((u32)ea_inode->i_version);
 297 }
 298
 299 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 300 {
 301         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 302         ea_inode->i_version = (u32)ref_count;
 303 }
 304
 305 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 306 {
 307         return (u32)ea_inode->i_atime.tv_sec;
 308 }
 309
 310 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 311 {
 312         ea_inode->i_atime.tv_sec = hash;
 313 }
 314
 315 /*
 316  * Read the EA value from an inode.
 317  */
 318 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 319 {
 320         int blocksize = 1 << ea_inode->i_blkbits;
 321         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 322         int tail_size = (size % blocksize) ?: blocksize;
 323         struct buffer_head *bhs_inline[8];
 324         struct buffer_head **bhs = bhs_inline;
 325         int i, ret;
 326
 327         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 328                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 329                 if (!bhs)
 330                         return -ENOMEM;
 331         }
 332
 333         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 334                                true /* wait */, bhs);
 335         if (ret)
 336                 goto free_bhs;
 337
 338         for (i = 0; i < bh_count; i++) {
 339                 /* There shouldn't be any holes in ea_inode. */
 340                 if (!bhs[i]) {
 341                         ret = -EFSCORRUPTED;
 342                         goto put_bhs;
 343                 }
 344                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 345                        i < bh_count - 1 ? blocksize : tail_size);
 346         }
 347         ret = 0;
 348 put_bhs:
 349         for (i = 0; i < bh_count; i++)
 350                 brelse(bhs[i]);
 351 free_bhs:
 352         if (bhs != bhs_inline)
 353                 kfree(bhs);
 354         return ret;
 355 }
 356
 357 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 358
 359 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 360                                  u32 ea_inode_hash, struct inode **ea_inode)
 361 {
 362         struct inode *inode;
 363         int err;
 364
 365         inode = ext4_iget(parent->i_sb, ea_ino);
 366         if (IS_ERR(inode)) {
 367                 err = PTR_ERR(inode);
 368                 ext4_error(parent->i_sb,
 369                            "error while reading EA inode %lu err=%d", ea_ino,
 370                            err);
 371                 return err;
 372         }
 373
 374         if (is_bad_inode(inode)) {
 375                 ext4_error(parent->i_sb,
 376                            "error while reading EA inode %lu is_bad_inode",
 377                            ea_ino);
 378                 err = -EIO;
 379                 goto error;
 380         }
 381
 382         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 383                 ext4_error(parent->i_sb,
 384                            "EA inode %lu does not have EXT4_EA_INODE_FL flag",
 385                             ea_ino);
 386                 err = -EINVAL;
 387                 goto error;
 388         }
 389
 390         ext4_xattr_inode_set_class(inode);
 391
 392         /*
 393          * Check whether this is an old Lustre-style xattr inode. Lustre
 394          * implementation does not have hash validation, rather it has a
 395          * backpointer from ea_inode to the parent inode.
 396          */
 397         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 398             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 399             inode->i_generation == parent->i_generation) {
 400                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 401                 ext4_xattr_inode_set_ref(inode, 1);
 402         } else {
 403                 inode_lock(inode);
 404                 inode->i_flags |= S_NOQUOTA;
 405                 inode_unlock(inode);
 406         }
 407
 408         *ea_inode = inode;
 409         return 0;
 410 error:
 411         iput(inode);
 412         return err;
 413 }
 414
 415 static int
 416 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 417                                struct ext4_xattr_entry *entry, void *buffer,
 418                                size_t size)
 419 {
 420         u32 hash;
 421
 422         /* Verify stored hash matches calculated hash. */
 423         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 424         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 425                 return -EFSCORRUPTED;
 426
 427         if (entry) {
 428                 __le32 e_hash, tmp_data;
 429
 430                 /* Verify entry hash. */
 431                 tmp_data = cpu_to_le32(hash);
 432                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 433                                                &tmp_data, 1);
 434                 if (e_hash != entry->e_hash)
 435                         return -EFSCORRUPTED;
 436         }
 437         return 0;
 438 }
 439
 440 /*
 441  * Read xattr value from the EA inode.
 442  */
 443 static int
 444 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 445                      void *buffer, size_t size)
 446 {
 447         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 448         struct inode *ea_inode;
 449         int err;
 450
 451         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 452                                     le32_to_cpu(entry->e_hash), &ea_inode);
 453         if (err) {
 454                 ea_inode = NULL;
 455                 goto out;
 456         }
 457
 458         if (i_size_read(ea_inode) != size) {
 459                 ext4_warning_inode(ea_inode,
 460                                    "ea_inode file size=%llu entry size=%zu",
 461                                    i_size_read(ea_inode), size);
 462                 err = -EFSCORRUPTED;
 463                 goto out;
 464         }
 465
 466         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 467         if (err)
 468                 goto out;
 469
 470         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 471                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 472                                                      size);
 473                 if (err) {
 474                         ext4_warning_inode(ea_inode,
 475                                            "EA inode hash validation failed");
 476                         goto out;
 477                 }
 478
 479                 if (ea_inode_cache)
 480                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 481                                         ext4_xattr_inode_get_hash(ea_inode),
 482                                         ea_inode->i_ino, true /* reusable */);
 483         }
 484 out:
 485         iput(ea_inode);
 486         return err;
 487 }
 488
 489 static int
 490 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 491                      void *buffer, size_t buffer_size)
 492 {
 493         struct buffer_head *bh = NULL;
 494         struct ext4_xattr_entry *entry;
 495         size_t size;
 496         int error;
 497         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 498
 499         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 500                   name_index, name, buffer, (long)buffer_size);
 501
 502         error = -ENODATA;
 503         if (!EXT4_I(inode)->i_file_acl)
 504                 goto cleanup;
 505         ea_idebug(inode, "reading block %llu",
 506                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 507         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 508         if (!bh)
 509                 goto cleanup;
 510         ea_bdebug(bh, "b_count=%d, refcount=%d",
 511                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 512         if (ext4_xattr_check_block(inode, bh)) {
 513                 EXT4_ERROR_INODE(inode, "bad block %llu",
 514                                  EXT4_I(inode)->i_file_acl);
 515                 error = -EFSCORRUPTED;
 516                 goto cleanup;
 517         }
 518         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 519         entry = BFIRST(bh);
 520         error = ext4_xattr_find_entry(&entry, name_index, name, 1);
 521         if (error)
 522                 goto cleanup;
 523         size = le32_to_cpu(entry->e_value_size);
 524         if (buffer) {
 525                 error = -ERANGE;
 526                 if (size > buffer_size)
 527                         goto cleanup;
 528                 if (entry->e_value_inum) {
 529                         error = ext4_xattr_inode_get(inode, entry, buffer,
 530                                                      size);
 531                         if (error)
 532                                 goto cleanup;
 533                 } else {
 534                         memcpy(buffer, bh->b_data +
 535                                le16_to_cpu(entry->e_value_offs), size);
 536                 }
 537         }
 538         error = size;
 539
 540 cleanup:
 541         brelse(bh);
 542         return error;
 543 }
 544
 545 int
 546 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 547                      void *buffer, size_t buffer_size)
 548 {
 549         struct ext4_xattr_ibody_header *header;
 550         struct ext4_xattr_entry *entry;
 551         struct ext4_inode *raw_inode;
 552         struct ext4_iloc iloc;
 553         size_t size;
 554         void *end;
 555         int error;
 556
 557         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 558                 return -ENODATA;
 559         error = ext4_get_inode_loc(inode, &iloc);
 560         if (error)
 561                 return error;
 562         raw_inode = ext4_raw_inode(&iloc);
 563         header = IHDR(inode, raw_inode);
 564         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 565         error = xattr_check_inode(inode, header, end);
 566         if (error)
 567                 goto cleanup;
 568         entry = IFIRST(header);
 569         error = ext4_xattr_find_entry(&entry, name_index, name, 0);
 570         if (error)
 571                 goto cleanup;
 572         size = le32_to_cpu(entry->e_value_size);
 573         if (buffer) {
 574                 error = -ERANGE;
 575                 if (size > buffer_size)
 576                         goto cleanup;
 577                 if (entry->e_value_inum) {
 578                         error = ext4_xattr_inode_get(inode, entry, buffer,
 579                                                      size);
 580                         if (error)
 581                                 goto cleanup;
 582                 } else {
 583                         memcpy(buffer, (void *)IFIRST(header) +
 584                                le16_to_cpu(entry->e_value_offs), size);
 585                 }
 586         }
 587         error = size;
 588
 589 cleanup:
 590         brelse(iloc.bh);
 591         return error;
 592 }
 593
 594 /*
 595  * ext4_xattr_get()
 596  *
 597  * Copy an extended attribute into the buffer
 598  * provided, or compute the buffer size required.
 599  * Buffer is NULL to compute the size of the buffer required.
 600  *
 601  * Returns a negative error number on failure, or the number of bytes
 602  * used / required on success.
 603  */
 604 int
 605 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 606                void *buffer, size_t buffer_size)
 607 {
 608         int error;
 609
 610         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 611                 return -EIO;
 612
 613         if (strlen(name) > 255)
 614                 return -ERANGE;
 615
 616         down_read(&EXT4_I(inode)->xattr_sem);
 617         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 618                                      buffer_size);
 619         if (error == -ENODATA)
 620                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 621                                              buffer_size);
 622         up_read(&EXT4_I(inode)->xattr_sem);
 623         return error;
 624 }
 625
 626 static int
 627 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 628                         char *buffer, size_t buffer_size)
 629 {
 630         size_t rest = buffer_size;
 631
 632         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 633                 const struct xattr_handler *handler =
 634                         ext4_xattr_handler(entry->e_name_index);
 635
 636                 if (handler && (!handler->list || handler->list(dentry))) {
 637                         const char *prefix = handler->prefix ?: handler->name;
 638                         size_t prefix_len = strlen(prefix);
 639                         size_t size = prefix_len + entry->e_name_len + 1;
 640
 641                         if (buffer) {
 642                                 if (size > rest)
 643                                         return -ERANGE;
 644                                 memcpy(buffer, prefix, prefix_len);
 645                                 buffer += prefix_len;
 646                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 647                                 buffer += entry->e_name_len;
 648                                 *buffer++ = 0;
 649                         }
 650                         rest -= size;
 651                 }
 652         }
 653         return buffer_size - rest;  /* total size */
 654 }
 655
 656 static int
 657 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 658 {
 659         struct inode *inode = d_inode(dentry);
 660         struct buffer_head *bh = NULL;
 661         int error;
 662
 663         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 664                   buffer, (long)buffer_size);
 665
 666         error = 0;
 667         if (!EXT4_I(inode)->i_file_acl)
 668                 goto cleanup;
 669         ea_idebug(inode, "reading block %llu",
 670                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 671         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 672         error = -EIO;
 673         if (!bh)
 674                 goto cleanup;
 675         ea_bdebug(bh, "b_count=%d, refcount=%d",
 676                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 677         if (ext4_xattr_check_block(inode, bh)) {
 678                 EXT4_ERROR_INODE(inode, "bad block %llu",
 679                                  EXT4_I(inode)->i_file_acl);
 680                 error = -EFSCORRUPTED;
 681                 goto cleanup;
 682         }
 683         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 684         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 685
 686 cleanup:
 687         brelse(bh);
 688
 689         return error;
 690 }
 691
 692 static int
 693 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 694 {
 695         struct inode *inode = d_inode(dentry);
 696         struct ext4_xattr_ibody_header *header;
 697         struct ext4_inode *raw_inode;
 698         struct ext4_iloc iloc;
 699         void *end;
 700         int error;
 701
 702         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 703                 return 0;
 704         error = ext4_get_inode_loc(inode, &iloc);
 705         if (error)
 706                 return error;
 707         raw_inode = ext4_raw_inode(&iloc);
 708         header = IHDR(inode, raw_inode);
 709         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 710         error = xattr_check_inode(inode, header, end);
 711         if (error)
 712                 goto cleanup;
 713         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 714                                         buffer, buffer_size);
 715
 716 cleanup:
 717         brelse(iloc.bh);
 718         return error;
 719 }
 720
 721 /*
 722  * Inode operation listxattr()
 723  *
 724  * d_inode(dentry)->i_rwsem: don't care
 725  *
 726  * Copy a list of attribute names into the buffer
 727  * provided, or compute the buffer size required.
 728  * Buffer is NULL to compute the size of the buffer required.
 729  *
 730  * Returns a negative error number on failure, or the number of bytes
 731  * used / required on success.
 732  */
 733 ssize_t
 734 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 735 {
 736         int ret, ret2;
 737
 738         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 739         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 740         if (ret < 0)
 741                 goto errout;
 742         if (buffer) {
 743                 buffer += ret;
 744                 buffer_size -= ret;
 745         }
 746         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 747         if (ret < 0)
 748                 goto errout;
 749         ret += ret2;
 750 errout:
 751         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 752         return ret;
 753 }
 754
 755 /*
 756  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 757  * not set, set it.
 758  */
 759 static void ext4_xattr_update_super_block(handle_t *handle,
 760                                           struct super_block *sb)
 761 {
 762         if (ext4_has_feature_xattr(sb))
 763                 return;
 764
 765         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 766         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 767                 ext4_set_feature_xattr(sb);
 768                 ext4_handle_dirty_super(handle, sb);
 769         }
 770 }
 771
 772 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 773 {
 774         struct ext4_iloc iloc = { .bh = NULL };
 775         struct buffer_head *bh = NULL;
 776         struct ext4_inode *raw_inode;
 777         struct ext4_xattr_ibody_header *header;
 778         struct ext4_xattr_entry *entry;
 779         qsize_t ea_inode_refs = 0;
 780         void *end;
 781         int ret;
 782
 783         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 784
 785         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 786                 ret = ext4_get_inode_loc(inode, &iloc);
 787                 if (ret)
 788                         goto out;
 789                 raw_inode = ext4_raw_inode(&iloc);
 790                 header = IHDR(inode, raw_inode);
 791                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 792                 ret = xattr_check_inode(inode, header, end);
 793                 if (ret)
 794                         goto out;
 795
 796                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 797                      entry = EXT4_XATTR_NEXT(entry))
 798                         if (entry->e_value_inum)
 799                                 ea_inode_refs++;
 800         }
 801
 802         if (EXT4_I(inode)->i_file_acl) {
 803                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 804                 if (!bh) {
 805                         ret = -EIO;
 806                         goto out;
 807                 }
 808
 809                 if (ext4_xattr_check_block(inode, bh)) {
 810                         ret = -EFSCORRUPTED;
 811                         goto out;
 812                 }
 813
 814                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 815                      entry = EXT4_XATTR_NEXT(entry))
 816                         if (entry->e_value_inum)
 817                                 ea_inode_refs++;
 818         }
 819         *usage = ea_inode_refs + 1;
 820         ret = 0;
 821 out:
 822         brelse(iloc.bh);
 823         brelse(bh);
 824         return ret;
 825 }
 826
 827 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 828 {
 829         struct super_block *sb = inode->i_sb;
 830         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 831                                     inode->i_blkbits);
 832         size_t mask = ~(cluster_size - 1);
 833
 834         return (length + cluster_size - 1) & mask;
 835 }
 836
 837 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 838 {
 839         int err;
 840
 841         err = dquot_alloc_inode(inode);
 842         if (err)
 843                 return err;
 844         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 845         if (err)
 846                 dquot_free_inode(inode);
 847         return err;
 848 }
 849
 850 static void ext4_xattr_inode_free_quota(struct inode *parent,
 851                                         struct inode *ea_inode,
 852                                         size_t len)
 853 {
 854         if (ea_inode &&
 855             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 856                 return;
 857         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 858         dquot_free_inode(parent);
 859 }
 860
 861 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 862                              struct buffer_head *block_bh, size_t value_len,
 863                              bool is_create)
 864 {
 865         int credits;
 866         int blocks;
 867
 868         /*
 869          * 1) Owner inode update
 870          * 2) Ref count update on old xattr block
 871          * 3) new xattr block
 872          * 4) block bitmap update for new xattr block
 873          * 5) group descriptor for new xattr block
 874          * 6) block bitmap update for old xattr block
 875          * 7) group descriptor for old block
 876          *
 877          * 6 & 7 can happen if we have two racing threads T_a and T_b
 878          * which are each trying to set an xattr on inodes I_a and I_b
 879          * which were both initially sharing an xattr block.
 880          */
 881         credits = 7;
 882
 883         /* Quota updates. */
 884         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 885
 886         /*
 887          * In case of inline data, we may push out the data to a block,
 888          * so we need to reserve credits for this eventuality
 889          */
 890         if (inode && ext4_has_inline_data(inode))
 891                 credits += ext4_writepage_trans_blocks(inode) + 1;
 892
 893         /* We are done if ea_inode feature is not enabled. */
 894         if (!ext4_has_feature_ea_inode(sb))
 895                 return credits;
 896
 897         /* New ea_inode, inode map, block bitmap, group descriptor. */
 898         credits += 4;
 899
 900         /* Data blocks. */
 901         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 902
 903         /* Indirection block or one level of extent tree. */
 904         blocks += 1;
 905
 906         /* Block bitmap and group descriptor updates for each block. */
 907         credits += blocks * 2;
 908
 909         /* Blocks themselves. */
 910         credits += blocks;
 911
 912         if (!is_create) {
 913                 /* Dereference ea_inode holding old xattr value.
 914                  * Old ea_inode, inode map, block bitmap, group descriptor.
 915                  */
 916                 credits += 4;
 917
 918                 /* Data blocks for old ea_inode. */
 919                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 920
 921                 /* Indirection block or one level of extent tree for old
 922                  * ea_inode.
 923                  */
 924                 blocks += 1;
 925
 926                 /* Block bitmap and group descriptor updates for each block. */
 927                 credits += blocks * 2;
 928         }
 929
 930         /* We may need to clone the existing xattr block in which case we need
 931          * to increment ref counts for existing ea_inodes referenced by it.
 932          */
 933         if (block_bh) {
 934                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 935
 936                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 937                         if (entry->e_value_inum)
 938                                 /* Ref count update on ea_inode. */
 939                                 credits += 1;
 940         }
 941         return credits;
 942 }
 943
 944 static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 945                                      int credits, struct buffer_head *bh,
 946                                      bool dirty, bool block_csum)
 947 {
 948         int error;
 949
 950         if (!ext4_handle_valid(handle))
 951                 return 0;
 952
 953         if (handle->h_buffer_credits >= credits)
 954                 return 0;
 955
 956         error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
 957         if (!error)
 958                 return 0;
 959         if (error < 0) {
 960                 ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
 961                 return error;
 962         }
 963
 964         if (bh && dirty) {
 965                 if (block_csum)
 966                         ext4_xattr_block_csum_set(inode, bh);
 967                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
 968                 if (error) {
 969                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
 970                                      error);
 971                         return error;
 972                 }
 973         }
 974
 975         error = ext4_journal_restart(handle, credits);
 976         if (error) {
 977                 ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
 978                 return error;
 979         }
 980
 981         if (bh) {
 982                 error = ext4_journal_get_write_access(handle, bh);
 983                 if (error) {
 984                         ext4_warning(inode->i_sb,
 985                                      "Get write access failed (error %d)",
 986                                      error);
 987                         return error;
 988                 }
 989         }
 990         return 0;
 991 }
 992
 993 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 994                                        int ref_change)
 995 {
 996         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
 997         struct ext4_iloc iloc;
 998         s64 ref_count;
 999         u32 hash;
1000         int ret;
1001
1002         inode_lock(ea_inode);
1003
1004         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1005         if (ret) {
1006                 iloc.bh = NULL;
1007                 goto out;
1008         }
1009
1010         ref_count = ext4_xattr_inode_get_ref(ea_inode);
1011         ref_count += ref_change;
1012         ext4_xattr_inode_set_ref(ea_inode, ref_count);
1013
1014         if (ref_change > 0) {
1015                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1016                           ea_inode->i_ino, ref_count);
1017
1018                 if (ref_count == 1) {
1019                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1020                                   ea_inode->i_ino, ea_inode->i_nlink);
1021
1022                         set_nlink(ea_inode, 1);
1023                         ext4_orphan_del(handle, ea_inode);
1024
1025                         if (ea_inode_cache) {
1026                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1027                                 mb_cache_entry_create(ea_inode_cache,
1028                                                       GFP_NOFS, hash,
1029                                                       ea_inode->i_ino,
1030                                                       true /* reusable */);
1031                         }
1032                 }
1033         } else {
1034                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1035                           ea_inode->i_ino, ref_count);
1036
1037                 if (ref_count == 0) {
1038                         WARN_ONCE(ea_inode->i_nlink != 1,
1039                                   "EA inode %lu i_nlink=%u",
1040                                   ea_inode->i_ino, ea_inode->i_nlink);
1041
1042                         clear_nlink(ea_inode);
1043                         ext4_orphan_add(handle, ea_inode);
1044
1045                         if (ea_inode_cache) {
1046                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1047                                 mb_cache_entry_delete(ea_inode_cache, hash,
1048                                                       ea_inode->i_ino);
1049                         }
1050                 }
1051         }
1052
1053         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1054         iloc.bh = NULL;
1055         if (ret)
1056                 ext4_warning_inode(ea_inode,
1057                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1058 out:
1059         brelse(iloc.bh);
1060         inode_unlock(ea_inode);
1061         return ret;
1062 }
1063
1064 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1065 {
1066         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1067 }
1068
1069 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1070 {
1071         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1072 }
1073
1074 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1075                                         struct ext4_xattr_entry *first)
1076 {
1077         struct inode *ea_inode;
1078         struct ext4_xattr_entry *entry;
1079         struct ext4_xattr_entry *failed_entry;
1080         unsigned int ea_ino;
1081         int err, saved_err;
1082
1083         for (entry = first; !IS_LAST_ENTRY(entry);
1084              entry = EXT4_XATTR_NEXT(entry)) {
1085                 if (!entry->e_value_inum)
1086                         continue;
1087                 ea_ino = le32_to_cpu(entry->e_value_inum);
1088                 err = ext4_xattr_inode_iget(parent, ea_ino,
1089                                             le32_to_cpu(entry->e_hash),
1090                                             &ea_inode);
1091                 if (err)
1092                         goto cleanup;
1093                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1094                 if (err) {
1095                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1096                         iput(ea_inode);
1097                         goto cleanup;
1098                 }
1099                 iput(ea_inode);
1100         }
1101         return 0;
1102
1103 cleanup:
1104         saved_err = err;
1105         failed_entry = entry;
1106
1107         for (entry = first; entry != failed_entry;
1108              entry = EXT4_XATTR_NEXT(entry)) {
1109                 if (!entry->e_value_inum)
1110                         continue;
1111                 ea_ino = le32_to_cpu(entry->e_value_inum);
1112                 err = ext4_xattr_inode_iget(parent, ea_ino,
1113                                             le32_to_cpu(entry->e_hash),
1114                                             &ea_inode);
1115                 if (err) {
1116                         ext4_warning(parent->i_sb,
1117                                      "cleanup ea_ino %u iget error %d", ea_ino,
1118                                      err);
1119                         continue;
1120                 }
1121                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1122                 if (err)
1123                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1124                                            err);
1125                 iput(ea_inode);
1126         }
1127         return saved_err;
1128 }
1129
1130 static void
1131 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1132                              struct buffer_head *bh,
1133                              struct ext4_xattr_entry *first, bool block_csum,
1134                              struct ext4_xattr_inode_array **ea_inode_array,
1135                              int extra_credits, bool skip_quota)
1136 {
1137         struct inode *ea_inode;
1138         struct ext4_xattr_entry *entry;
1139         bool dirty = false;
1140         unsigned int ea_ino;
1141         int err;
1142         int credits;
1143
1144         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1145         credits = 2 + extra_credits;
1146
1147         for (entry = first; !IS_LAST_ENTRY(entry);
1148              entry = EXT4_XATTR_NEXT(entry)) {
1149                 if (!entry->e_value_inum)
1150                         continue;
1151                 ea_ino = le32_to_cpu(entry->e_value_inum);
1152                 err = ext4_xattr_inode_iget(parent, ea_ino,
1153                                             le32_to_cpu(entry->e_hash),
1154                                             &ea_inode);
1155                 if (err)
1156                         continue;
1157
1158                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1159                 if (err) {
1160                         ext4_warning_inode(ea_inode,
1161                                            "Expand inode array err=%d", err);
1162                         iput(ea_inode);
1163                         continue;
1164                 }
1165
1166                 err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
1167                                                 dirty, block_csum);
1168                 if (err) {
1169                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1170                                            err);
1171                         continue;
1172                 }
1173
1174                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1175                 if (err) {
1176                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1177                                            err);
1178                         continue;
1179                 }
1180
1181                 if (!skip_quota)
1182                         ext4_xattr_inode_free_quota(parent, ea_inode,
1183                                               le32_to_cpu(entry->e_value_size));
1184
1185                 /*
1186                  * Forget about ea_inode within the same transaction that
1187                  * decrements the ref count. This avoids duplicate decrements in
1188                  * case the rest of the work spills over to subsequent
1189                  * transactions.
1190                  */
1191                 entry->e_value_inum = 0;
1192                 entry->e_value_size = 0;
1193
1194                 dirty = true;
1195         }
1196
1197         if (dirty) {
1198                 /*
1199                  * Note that we are deliberately skipping csum calculation for
1200                  * the final update because we do not expect any journal
1201                  * restarts until xattr block is freed.
1202                  */
1203
1204                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1205                 if (err)
1206                         ext4_warning_inode(parent,
1207                                            "handle dirty metadata err=%d", err);
1208         }
1209 }
1210
1211 /*
1212  * Release the xattr block BH: If the reference count is > 1, decrement it;
1213  * otherwise free the block.
1214  */
1215 static void
1216 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1217                          struct buffer_head *bh,
1218                          struct ext4_xattr_inode_array **ea_inode_array,
1219                          int extra_credits)
1220 {
1221         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1222         u32 hash, ref;
1223         int error = 0;
1224
1225         BUFFER_TRACE(bh, "get_write_access");
1226         error = ext4_journal_get_write_access(handle, bh);
1227         if (error)
1228                 goto out;
1229
1230         lock_buffer(bh);
1231         hash = le32_to_cpu(BHDR(bh)->h_hash);
1232         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1233         if (ref == 1) {
1234                 ea_bdebug(bh, "refcount now=0; freeing");
1235                 /*
1236                  * This must happen under buffer lock for
1237                  * ext4_xattr_block_set() to reliably detect freed block
1238                  */
1239                 if (ea_block_cache)
1240                         mb_cache_entry_delete(ea_block_cache, hash,
1241                                               bh->b_blocknr);
1242                 get_bh(bh);
1243                 unlock_buffer(bh);
1244
1245                 if (ext4_has_feature_ea_inode(inode->i_sb))
1246                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1247                                                      BFIRST(bh),
1248                                                      true /* block_csum */,
1249                                                      ea_inode_array,
1250                                                      extra_credits,
1251                                                      true /* skip_quota */);
1252                 ext4_free_blocks(handle, inode, bh, 0, 1,
1253                                  EXT4_FREE_BLOCKS_METADATA |
1254                                  EXT4_FREE_BLOCKS_FORGET);
1255         } else {
1256                 ref--;
1257                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1258                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1259                         struct mb_cache_entry *ce;
1260
1261                         if (ea_block_cache) {
1262                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1263                                                         bh->b_blocknr);
1264                                 if (ce) {
1265                                         ce->e_reusable = 1;
1266                                         mb_cache_entry_put(ea_block_cache, ce);
1267                                 }
1268                         }
1269                 }
1270
1271                 ext4_xattr_block_csum_set(inode, bh);
1272                 /*
1273                  * Beware of this ugliness: Releasing of xattr block references
1274                  * from different inodes can race and so we have to protect
1275                  * from a race where someone else frees the block (and releases
1276                  * its journal_head) before we are done dirtying the buffer. In
1277                  * nojournal mode this race is harmless and we actually cannot
1278                  * call ext4_handle_dirty_metadata() with locked buffer as
1279                  * that function can call sync_dirty_buffer() so for that case
1280                  * we handle the dirtying after unlocking the buffer.
1281                  */
1282                 if (ext4_handle_valid(handle))
1283                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1284                 unlock_buffer(bh);
1285                 if (!ext4_handle_valid(handle))
1286                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1287                 if (IS_SYNC(inode))
1288                         ext4_handle_sync(handle);
1289                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1290                 ea_bdebug(bh, "refcount now=%d; releasing",
1291                           le32_to_cpu(BHDR(bh)->h_refcount));
1292         }
1293 out:
1294         ext4_std_error(inode->i_sb, error);
1295         return;
1296 }
1297
1298 /*
1299  * Find the available free space for EAs. This also returns the total number of
1300  * bytes used by EA entries.
1301  */
1302 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1303                                     size_t *min_offs, void *base, int *total)
1304 {
1305         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1306                 if (!last->e_value_inum && last->e_value_size) {
1307                         size_t offs = le16_to_cpu(last->e_value_offs);
1308                         if (offs < *min_offs)
1309                                 *min_offs = offs;
1310                 }
1311                 if (total)
1312                         *total += EXT4_XATTR_LEN(last->e_name_len);
1313         }
1314         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1315 }
1316
1317 /*
1318  * Write the value of the EA in an inode.
1319  */
1320 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1321                                   const void *buf, int bufsize)
1322 {
1323         struct buffer_head *bh = NULL;
1324         unsigned long block = 0;
1325         int blocksize = ea_inode->i_sb->s_blocksize;
1326         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1327         int csize, wsize = 0;
1328         int ret = 0;
1329         int retries = 0;
1330
1331 retry:
1332         while (ret >= 0 && ret < max_blocks) {
1333                 struct ext4_map_blocks map;
1334                 map.m_lblk = block += ret;
1335                 map.m_len = max_blocks -= ret;
1336
1337                 ret = ext4_map_blocks(handle, ea_inode, &map,
1338                                       EXT4_GET_BLOCKS_CREATE);
1339                 if (ret <= 0) {
1340                         ext4_mark_inode_dirty(handle, ea_inode);
1341                         if (ret == -ENOSPC &&
1342                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1343                                 ret = 0;
1344                                 goto retry;
1345                         }
1346                         break;
1347                 }
1348         }
1349
1350         if (ret < 0)
1351                 return ret;
1352
1353         block = 0;
1354         while (wsize < bufsize) {
1355                 if (bh != NULL)
1356                         brelse(bh);
1357                 csize = (bufsize - wsize) > blocksize ? blocksize :
1358                                                                 bufsize - wsize;
1359                 bh = ext4_getblk(handle, ea_inode, block, 0);
1360                 if (IS_ERR(bh))
1361                         return PTR_ERR(bh);
1362                 ret = ext4_journal_get_write_access(handle, bh);
1363                 if (ret)
1364                         goto out;
1365
1366                 memcpy(bh->b_data, buf, csize);
1367                 set_buffer_uptodate(bh);
1368                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1369
1370                 buf += csize;
1371                 wsize += csize;
1372                 block += 1;
1373         }
1374
1375         inode_lock(ea_inode);
1376         i_size_write(ea_inode, wsize);
1377         ext4_update_i_disksize(ea_inode, wsize);
1378         inode_unlock(ea_inode);
1379
1380         ext4_mark_inode_dirty(handle, ea_inode);
1381
1382 out:
1383         brelse(bh);
1384
1385         return ret;
1386 }
1387
1388 /*
1389  * Create an inode to store the value of a large EA.
1390  */
1391 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1392                                              struct inode *inode, u32 hash)
1393 {
1394         struct inode *ea_inode = NULL;
1395         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1396         int err;
1397
1398         /*
1399          * Let the next inode be the goal, so we try and allocate the EA inode
1400          * in the same group, or nearby one.
1401          */
1402         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1403                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1404                                   EXT4_EA_INODE_FL);
1405         if (!IS_ERR(ea_inode)) {
1406                 ea_inode->i_op = &ext4_file_inode_operations;
1407                 ea_inode->i_fop = &ext4_file_operations;
1408                 ext4_set_aops(ea_inode);
1409                 ext4_xattr_inode_set_class(ea_inode);
1410                 unlock_new_inode(ea_inode);
1411                 ext4_xattr_inode_set_ref(ea_inode, 1);
1412                 ext4_xattr_inode_set_hash(ea_inode, hash);
1413                 err = ext4_mark_inode_dirty(handle, ea_inode);
1414                 if (!err)
1415                         err = ext4_inode_attach_jinode(ea_inode);
1416                 if (err) {
1417                         iput(ea_inode);
1418                         return ERR_PTR(err);
1419                 }
1420
1421                 /*
1422                  * Xattr inodes are shared therefore quota charging is performed
1423                  * at a higher level.
1424                  */
1425                 dquot_free_inode(ea_inode);
1426                 dquot_drop(ea_inode);
1427                 inode_lock(ea_inode);
1428                 ea_inode->i_flags |= S_NOQUOTA;
1429                 inode_unlock(ea_inode);
1430         }
1431
1432         return ea_inode;
1433 }
1434
1435 static struct inode *
1436 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1437                             size_t value_len, u32 hash)
1438 {
1439         struct inode *ea_inode;
1440         struct mb_cache_entry *ce;
1441         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1442         void *ea_data;
1443
1444         if (!ea_inode_cache)
1445                 return NULL;
1446
1447         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1448         if (!ce)
1449                 return NULL;
1450
1451         ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
1452         if (!ea_data) {
1453                 mb_cache_entry_put(ea_inode_cache, ce);
1454                 return NULL;
1455         }
1456
1457         while (ce) {
1458                 ea_inode = ext4_iget(inode->i_sb, ce->e_value);
1459                 if (!IS_ERR(ea_inode) &&
1460                     !is_bad_inode(ea_inode) &&
1461                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1462                     i_size_read(ea_inode) == value_len &&
1463                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1464                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1465                                                     value_len) &&
1466                     !memcmp(value, ea_data, value_len)) {
1467                         mb_cache_entry_touch(ea_inode_cache, ce);
1468                         mb_cache_entry_put(ea_inode_cache, ce);
1469                         kvfree(ea_data);
1470                         return ea_inode;
1471                 }
1472
1473                 if (!IS_ERR(ea_inode))
1474                         iput(ea_inode);
1475                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1476         }
1477         kvfree(ea_data);
1478         return NULL;
1479 }
1480
1481 /*
1482  * Add value of the EA in an inode.
1483  */
1484 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1485                                           const void *value, size_t value_len,
1486                                           struct inode **ret_inode)
1487 {
1488         struct inode *ea_inode;
1489         u32 hash;
1490         int err;
1491
1492         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1493         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1494         if (ea_inode) {
1495                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1496                 if (err) {
1497                         iput(ea_inode);
1498                         return err;
1499                 }
1500
1501                 *ret_inode = ea_inode;
1502                 return 0;
1503         }
1504
1505         /* Create an inode for the EA value */
1506         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1507         if (IS_ERR(ea_inode))
1508                 return PTR_ERR(ea_inode);
1509
1510         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1511         if (err) {
1512                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1513                 iput(ea_inode);
1514                 return err;
1515         }
1516
1517         if (EA_INODE_CACHE(inode))
1518                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1519                                       ea_inode->i_ino, true /* reusable */);
1520
1521         *ret_inode = ea_inode;
1522         return 0;
1523 }
1524
1525 /*
1526  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1527  * feature is enabled.
1528  */
1529 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1530
1531 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1532                                 struct ext4_xattr_search *s,
1533                                 handle_t *handle, struct inode *inode,
1534                                 bool is_block)
1535 {
1536         struct ext4_xattr_entry *last;
1537         struct ext4_xattr_entry *here = s->here;
1538         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1539         int in_inode = i->in_inode;
1540         struct inode *old_ea_inode = NULL;
1541         struct inode *new_ea_inode = NULL;
1542         size_t old_size, new_size;
1543         int ret;
1544
1545         /* Space used by old and new values. */
1546         old_size = (!s->not_found && !here->e_value_inum) ?
1547                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1548         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1549
1550         /*
1551          * Optimization for the simple case when old and new values have the
1552          * same padded sizes. Not applicable if external inodes are involved.
1553          */
1554         if (new_size && new_size == old_size) {
1555                 size_t offs = le16_to_cpu(here->e_value_offs);
1556                 void *val = s->base + offs;
1557
1558                 here->e_value_size = cpu_to_le32(i->value_len);
1559                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1560                         memset(val, 0, new_size);
1561                 } else {
1562                         memcpy(val, i->value, i->value_len);
1563                         /* Clear padding bytes. */
1564                         memset(val + i->value_len, 0, new_size - i->value_len);
1565                 }
1566                 goto update_hash;
1567         }
1568
1569         /* Compute min_offs and last. */
1570         last = s->first;
1571         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1572                 if (!last->e_value_inum && last->e_value_size) {
1573                         size_t offs = le16_to_cpu(last->e_value_offs);
1574                         if (offs < min_offs)
1575                                 min_offs = offs;
1576                 }
1577         }
1578
1579         /* Check whether we have enough space. */
1580         if (i->value) {
1581                 size_t free;
1582
1583                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1584                 if (!s->not_found)
1585                         free += EXT4_XATTR_LEN(name_len) + old_size;
1586
1587                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1588                         ret = -ENOSPC;
1589                         goto out;
1590                 }
1591
1592                 /*
1593                  * If storing the value in an external inode is an option,
1594                  * reserve space for xattr entries/names in the external
1595                  * attribute block so that a long value does not occupy the
1596                  * whole space and prevent futher entries being added.
1597                  */
1598                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1599                     new_size && is_block &&
1600                     (min_offs + old_size - new_size) <
1601                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1602                         ret = -ENOSPC;
1603                         goto out;
1604                 }
1605         }
1606
1607         /*
1608          * Getting access to old and new ea inodes is subject to failures.
1609          * Finish that work before doing any modifications to the xattr data.
1610          */
1611         if (!s->not_found && here->e_value_inum) {
1612                 ret = ext4_xattr_inode_iget(inode,
1613                                             le32_to_cpu(here->e_value_inum),
1614                                             le32_to_cpu(here->e_hash),
1615                                             &old_ea_inode);
1616                 if (ret) {
1617                         old_ea_inode = NULL;
1618                         goto out;
1619                 }
1620         }
1621         if (i->value && in_inode) {
1622                 WARN_ON_ONCE(!i->value_len);
1623
1624                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1625                 if (ret)
1626                         goto out;
1627
1628                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1629                                                      i->value_len,
1630                                                      &new_ea_inode);
1631                 if (ret) {
1632                         new_ea_inode = NULL;
1633                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1634                         goto out;
1635                 }
1636         }
1637
1638         if (old_ea_inode) {
1639                 /* We are ready to release ref count on the old_ea_inode. */
1640                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1641                 if (ret) {
1642                         /* Release newly required ref count on new_ea_inode. */
1643                         if (new_ea_inode) {
1644                                 int err;
1645
1646                                 err = ext4_xattr_inode_dec_ref(handle,
1647                                                                new_ea_inode);
1648                                 if (err)
1649                                         ext4_warning_inode(new_ea_inode,
1650                                                   "dec ref new_ea_inode err=%d",
1651                                                   err);
1652                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1653                                                             i->value_len);
1654                         }
1655                         goto out;
1656                 }
1657
1658                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1659                                             le32_to_cpu(here->e_value_size));
1660         }
1661
1662         /* No failures allowed past this point. */
1663
1664         if (!s->not_found && here->e_value_offs) {
1665                 /* Remove the old value. */
1666                 void *first_val = s->base + min_offs;
1667                 size_t offs = le16_to_cpu(here->e_value_offs);
1668                 void *val = s->base + offs;
1669
1670                 memmove(first_val + old_size, first_val, val - first_val);
1671                 memset(first_val, 0, old_size);
1672                 min_offs += old_size;
1673
1674                 /* Adjust all value offsets. */
1675                 last = s->first;
1676                 while (!IS_LAST_ENTRY(last)) {
1677                         size_t o = le16_to_cpu(last->e_value_offs);
1678
1679                         if (!last->e_value_inum &&
1680                             last->e_value_size && o < offs)
1681                                 last->e_value_offs = cpu_to_le16(o + old_size);
1682                         last = EXT4_XATTR_NEXT(last);
1683                 }
1684         }
1685
1686         if (!i->value) {
1687                 /* Remove old name. */
1688                 size_t size = EXT4_XATTR_LEN(name_len);
1689
1690                 last = ENTRY((void *)last - size);
1691                 memmove(here, (void *)here + size,
1692                         (void *)last - (void *)here + sizeof(__u32));
1693                 memset(last, 0, size);
1694         } else if (s->not_found) {
1695                 /* Insert new name. */
1696                 size_t size = EXT4_XATTR_LEN(name_len);
1697                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1698
1699                 memmove((void *)here + size, here, rest);
1700                 memset(here, 0, size);
1701                 here->e_name_index = i->name_index;
1702                 here->e_name_len = name_len;
1703                 memcpy(here->e_name, i->name, name_len);
1704         } else {
1705                 /* This is an update, reset value info. */
1706                 here->e_value_inum = 0;
1707                 here->e_value_offs = 0;
1708                 here->e_value_size = 0;
1709         }
1710
1711         if (i->value) {
1712                 /* Insert new value. */
1713                 if (in_inode) {
1714                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1715                 } else if (i->value_len) {
1716                         void *val = s->base + min_offs - new_size;
1717
1718                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1719                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1720                                 memset(val, 0, new_size);
1721                         } else {
1722                                 memcpy(val, i->value, i->value_len);
1723                                 /* Clear padding bytes. */
1724                                 memset(val + i->value_len, 0,
1725                                        new_size - i->value_len);
1726                         }
1727                 }
1728                 here->e_value_size = cpu_to_le32(i->value_len);
1729         }
1730
1731 update_hash:
1732         if (i->value) {
1733                 __le32 hash = 0;
1734
1735                 /* Entry hash calculation. */
1736                 if (in_inode) {
1737                         __le32 crc32c_hash;
1738
1739                         /*
1740                          * Feed crc32c hash instead of the raw value for entry
1741                          * hash calculation. This is to avoid walking
1742                          * potentially long value buffer again.
1743                          */
1744                         crc32c_hash = cpu_to_le32(
1745                                        ext4_xattr_inode_get_hash(new_ea_inode));
1746                         hash = ext4_xattr_hash_entry(here->e_name,
1747                                                      here->e_name_len,
1748                                                      &crc32c_hash, 1);
1749                 } else if (is_block) {
1750                         __le32 *value = s->base + le16_to_cpu(
1751                                                         here->e_value_offs);
1752
1753                         hash = ext4_xattr_hash_entry(here->e_name,
1754                                                      here->e_name_len, value,
1755                                                      new_size >> 2);
1756                 }
1757                 here->e_hash = hash;
1758         }
1759
1760         if (is_block)
1761                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1762
1763         ret = 0;
1764 out:
1765         iput(old_ea_inode);
1766         iput(new_ea_inode);
1767         return ret;
1768 }
1769
1770 struct ext4_xattr_block_find {
1771         struct ext4_xattr_search s;
1772         struct buffer_head *bh;
1773 };
1774
1775 static int
1776 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1777                       struct ext4_xattr_block_find *bs)
1778 {
1779         struct super_block *sb = inode->i_sb;
1780         int error;
1781
1782         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1783                   i->name_index, i->name, i->value, (long)i->value_len);
1784
1785         if (EXT4_I(inode)->i_file_acl) {
1786                 /* The inode already has an extended attribute block. */
1787                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
1788                 error = -EIO;
1789                 if (!bs->bh)
1790                         goto cleanup;
1791                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1792                         atomic_read(&(bs->bh->b_count)),
1793                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1794                 if (ext4_xattr_check_block(inode, bs->bh)) {
1795                         EXT4_ERROR_INODE(inode, "bad block %llu",
1796                                          EXT4_I(inode)->i_file_acl);
1797                         error = -EFSCORRUPTED;
1798                         goto cleanup;
1799                 }
1800                 /* Find the named attribute. */
1801                 bs->s.base = BHDR(bs->bh);
1802                 bs->s.first = BFIRST(bs->bh);
1803                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1804                 bs->s.here = bs->s.first;
1805                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
1806                                               i->name, 1);
1807                 if (error && error != -ENODATA)
1808                         goto cleanup;
1809                 bs->s.not_found = error;
1810         }
1811         error = 0;
1812
1813 cleanup:
1814         return error;
1815 }
1816
1817 static int
1818 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1819                      struct ext4_xattr_info *i,
1820                      struct ext4_xattr_block_find *bs)
1821 {
1822         struct super_block *sb = inode->i_sb;
1823         struct buffer_head *new_bh = NULL;
1824         struct ext4_xattr_search s_copy = bs->s;
1825         struct ext4_xattr_search *s = &s_copy;
1826         struct mb_cache_entry *ce = NULL;
1827         int error = 0;
1828         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1829         struct inode *ea_inode = NULL, *tmp_inode;
1830         size_t old_ea_inode_quota = 0;
1831         unsigned int ea_ino;
1832
1833
1834 #define header(x) ((struct ext4_xattr_header *)(x))
1835
1836         if (s->base) {
1837                 BUFFER_TRACE(bs->bh, "get_write_access");
1838                 error = ext4_journal_get_write_access(handle, bs->bh);
1839                 if (error)
1840                         goto cleanup;
1841                 lock_buffer(bs->bh);
1842
1843                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1844                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1845
1846                         /*
1847                          * This must happen under buffer lock for
1848                          * ext4_xattr_block_set() to reliably detect modified
1849                          * block
1850                          */
1851                         if (ea_block_cache)
1852                                 mb_cache_entry_delete(ea_block_cache, hash,
1853                                                       bs->bh->b_blocknr);
1854                         ea_bdebug(bs->bh, "modifying in-place");
1855                         error = ext4_xattr_set_entry(i, s, handle, inode,
1856                                                      true /* is_block */);
1857                         ext4_xattr_block_csum_set(inode, bs->bh);
1858                         unlock_buffer(bs->bh);
1859                         if (error == -EFSCORRUPTED)
1860                                 goto bad_block;
1861                         if (!error)
1862                                 error = ext4_handle_dirty_metadata(handle,
1863                                                                    inode,
1864                                                                    bs->bh);
1865                         if (error)
1866                                 goto cleanup;
1867                         goto inserted;
1868                 } else {
1869                         int offset = (char *)s->here - bs->bh->b_data;
1870
1871                         unlock_buffer(bs->bh);
1872                         ea_bdebug(bs->bh, "cloning");
1873                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1874                         error = -ENOMEM;
1875                         if (s->base == NULL)
1876                                 goto cleanup;
1877                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1878                         s->first = ENTRY(header(s->base)+1);
1879                         header(s->base)->h_refcount = cpu_to_le32(1);
1880                         s->here = ENTRY(s->base + offset);
1881                         s->end = s->base + bs->bh->b_size;
1882
1883                         /*
1884                          * If existing entry points to an xattr inode, we need
1885                          * to prevent ext4_xattr_set_entry() from decrementing
1886                          * ref count on it because the reference belongs to the
1887                          * original block. In this case, make the entry look
1888                          * like it has an empty value.
1889                          */
1890                         if (!s->not_found && s->here->e_value_inum) {
1891                                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1892                                 error = ext4_xattr_inode_iget(inode, ea_ino,
1893                                               le32_to_cpu(s->here->e_hash),
1894                                               &tmp_inode);
1895                                 if (error)
1896                                         goto cleanup;
1897
1898                                 if (!ext4_test_inode_state(tmp_inode,
1899                                                 EXT4_STATE_LUSTRE_EA_INODE)) {
1900                                         /*
1901                                          * Defer quota free call for previous
1902                                          * inode until success is guaranteed.
1903                                          */
1904                                         old_ea_inode_quota = le32_to_cpu(
1905                                                         s->here->e_value_size);
1906                                 }
1907                                 iput(tmp_inode);
1908
1909                                 s->here->e_value_inum = 0;
1910                                 s->here->e_value_size = 0;
1911                         }
1912                 }
1913         } else {
1914                 /* Allocate a buffer where we construct the new block. */
1915                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1916                 /* assert(header == s->base) */
1917                 error = -ENOMEM;
1918                 if (s->base == NULL)
1919                         goto cleanup;
1920                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1921                 header(s->base)->h_blocks = cpu_to_le32(1);
1922                 header(s->base)->h_refcount = cpu_to_le32(1);
1923                 s->first = ENTRY(header(s->base)+1);
1924                 s->here = ENTRY(header(s->base)+1);
1925                 s->end = s->base + sb->s_blocksize;
1926         }
1927
1928         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1929         if (error == -EFSCORRUPTED)
1930                 goto bad_block;
1931         if (error)
1932                 goto cleanup;
1933
1934         if (i->value && s->here->e_value_inum) {
1935                 /*
1936                  * A ref count on ea_inode has been taken as part of the call to
1937                  * ext4_xattr_set_entry() above. We would like to drop this
1938                  * extra ref but we have to wait until the xattr block is
1939                  * initialized and has its own ref count on the ea_inode.
1940                  */
1941                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1942                 error = ext4_xattr_inode_iget(inode, ea_ino,
1943                                               le32_to_cpu(s->here->e_hash),
1944                                               &ea_inode);
1945                 if (error) {
1946                         ea_inode = NULL;
1947                         goto cleanup;
1948                 }
1949         }
1950
1951 inserted:
1952         if (!IS_LAST_ENTRY(s->first)) {
1953                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1954                                                      &ce);
1955                 if (new_bh) {
1956                         /* We found an identical block in the cache. */
1957                         if (new_bh == bs->bh)
1958                                 ea_bdebug(new_bh, "keeping");
1959                         else {
1960                                 u32 ref;
1961
1962                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
1963
1964                                 /* The old block is released after updating
1965                                    the inode. */
1966                                 error = dquot_alloc_block(inode,
1967                                                 EXT4_C2B(EXT4_SB(sb), 1));
1968                                 if (error)
1969                                         goto cleanup;
1970                                 BUFFER_TRACE(new_bh, "get_write_access");
1971                                 error = ext4_journal_get_write_access(handle,
1972                                                                       new_bh);
1973                                 if (error)
1974                                         goto cleanup_dquot;
1975                                 lock_buffer(new_bh);
1976                                 /*
1977                                  * We have to be careful about races with
1978                                  * freeing, rehashing or adding references to
1979                                  * xattr block. Once we hold buffer lock xattr
1980                                  * block's state is stable so we can check
1981                                  * whether the block got freed / rehashed or
1982                                  * not.  Since we unhash mbcache entry under
1983                                  * buffer lock when freeing / rehashing xattr
1984                                  * block, checking whether entry is still
1985                                  * hashed is reliable. Same rules hold for
1986                                  * e_reusable handling.
1987                                  */
1988                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
1989                                     !ce->e_reusable) {
1990                                         /*
1991                                          * Undo everything and check mbcache
1992                                          * again.
1993                                          */
1994                                         unlock_buffer(new_bh);
1995                                         dquot_free_block(inode,
1996                                                          EXT4_C2B(EXT4_SB(sb),
1997                                                                   1));
1998                                         brelse(new_bh);
1999                                         mb_cache_entry_put(ea_block_cache, ce);
2000                                         ce = NULL;
2001                                         new_bh = NULL;
2002                                         goto inserted;
2003                                 }
2004                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2005                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2006                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2007                                         ce->e_reusable = 0;
2008                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2009                                           ref);
2010                                 ext4_xattr_block_csum_set(inode, new_bh);
2011                                 unlock_buffer(new_bh);
2012                                 error = ext4_handle_dirty_metadata(handle,
2013                                                                    inode,
2014                                                                    new_bh);
2015                                 if (error)
2016                                         goto cleanup_dquot;
2017                         }
2018                         mb_cache_entry_touch(ea_block_cache, ce);
2019                         mb_cache_entry_put(ea_block_cache, ce);
2020                         ce = NULL;
2021                 } else if (bs->bh && s->base == bs->bh->b_data) {
2022                         /* We were modifying this block in-place. */
2023                         ea_bdebug(bs->bh, "keeping this block");
2024                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2025                         new_bh = bs->bh;
2026                         get_bh(new_bh);
2027                 } else {
2028                         /* We need to allocate a new block */
2029                         ext4_fsblk_t goal, block;
2030
2031                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2032
2033                         goal = ext4_group_first_block_no(sb,
2034                                                 EXT4_I(inode)->i_block_group);
2035
2036                         /* non-extent files can't have physical blocks past 2^32 */
2037                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2038                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2039
2040                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2041                                                      NULL, &error);
2042                         if (error)
2043                                 goto cleanup;
2044
2045                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2046                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2047
2048                         ea_idebug(inode, "creating block %llu",
2049                                   (unsigned long long)block);
2050
2051                         new_bh = sb_getblk(sb, block);
2052                         if (unlikely(!new_bh)) {
2053                                 error = -ENOMEM;
2054 getblk_failed:
2055                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2056                                                  EXT4_FREE_BLOCKS_METADATA);
2057                                 goto cleanup;
2058                         }
2059                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2060                                                       ENTRY(header(s->base)+1));
2061                         if (error)
2062                                 goto getblk_failed;
2063                         if (ea_inode) {
2064                                 /* Drop the extra ref on ea_inode. */
2065                                 error = ext4_xattr_inode_dec_ref(handle,
2066                                                                  ea_inode);
2067                                 if (error)
2068                                         ext4_warning_inode(ea_inode,
2069                                                            "dec ref error=%d",
2070                                                            error);
2071                                 iput(ea_inode);
2072                                 ea_inode = NULL;
2073                         }
2074
2075                         lock_buffer(new_bh);
2076                         error = ext4_journal_get_create_access(handle, new_bh);
2077                         if (error) {
2078                                 unlock_buffer(new_bh);
2079                                 error = -EIO;
2080                                 goto getblk_failed;
2081                         }
2082                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2083                         ext4_xattr_block_csum_set(inode, new_bh);
2084                         set_buffer_uptodate(new_bh);
2085                         unlock_buffer(new_bh);
2086                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2087                         error = ext4_handle_dirty_metadata(handle, inode,
2088                                                            new_bh);
2089                         if (error)
2090                                 goto cleanup;
2091                 }
2092         }
2093
2094         if (old_ea_inode_quota)
2095                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2096
2097         /* Update the inode. */
2098         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2099
2100         /* Drop the previous xattr block. */
2101         if (bs->bh && bs->bh != new_bh) {
2102                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2103
2104                 ext4_xattr_release_block(handle, inode, bs->bh,
2105                                          &ea_inode_array,
2106                                          0 /* extra_credits */);
2107                 ext4_xattr_inode_array_free(ea_inode_array);
2108         }
2109         error = 0;
2110
2111 cleanup:
2112         if (ea_inode) {
2113                 int error2;
2114
2115                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2116                 if (error2)
2117                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2118                                            error2);
2119
2120                 /* If there was an error, revert the quota charge. */
2121                 if (error)
2122                         ext4_xattr_inode_free_quota(inode, ea_inode,
2123                                                     i_size_read(ea_inode));
2124                 iput(ea_inode);
2125         }
2126         if (ce)
2127                 mb_cache_entry_put(ea_block_cache, ce);
2128         brelse(new_bh);
2129         if (!(bs->bh && s->base == bs->bh->b_data))
2130                 kfree(s->base);
2131
2132         return error;
2133
2134 cleanup_dquot:
2135         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2136         goto cleanup;
2137
2138 bad_block:
2139         EXT4_ERROR_INODE(inode, "bad block %llu",
2140                          EXT4_I(inode)->i_file_acl);
2141         goto cleanup;
2142
2143 #undef header
2144 }
2145
2146 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2147                           struct ext4_xattr_ibody_find *is)
2148 {
2149         struct ext4_xattr_ibody_header *header;
2150         struct ext4_inode *raw_inode;
2151         int error;
2152
2153         if (EXT4_I(inode)->i_extra_isize == 0)
2154                 return 0;
2155         raw_inode = ext4_raw_inode(&is->iloc);
2156         header = IHDR(inode, raw_inode);
2157         is->s.base = is->s.first = IFIRST(header);
2158         is->s.here = is->s.first;
2159         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2160         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2161                 error = xattr_check_inode(inode, header, is->s.end);
2162                 if (error)
2163                         return error;
2164                 /* Find the named attribute. */
2165                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
2166                                               i->name, 0);
2167                 if (error && error != -ENODATA)
2168                         return error;
2169                 is->s.not_found = error;
2170         }
2171         return 0;
2172 }
2173
2174 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2175                                 struct ext4_xattr_info *i,
2176                                 struct ext4_xattr_ibody_find *is)
2177 {
2178         struct ext4_xattr_ibody_header *header;
2179         struct ext4_xattr_search *s = &is->s;
2180         int error;
2181
2182         if (EXT4_I(inode)->i_extra_isize == 0)
2183                 return -ENOSPC;
2184         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2185         if (error) {
2186                 if (error == -ENOSPC &&
2187                     ext4_has_inline_data(inode)) {
2188                         error = ext4_try_to_evict_inline_data(handle, inode,
2189                                         EXT4_XATTR_LEN(strlen(i->name) +
2190                                         EXT4_XATTR_SIZE(i->value_len)));
2191                         if (error)
2192                                 return error;
2193                         error = ext4_xattr_ibody_find(inode, i, is);
2194                         if (error)
2195                                 return error;
2196                         error = ext4_xattr_set_entry(i, s, handle, inode,
2197                                                      false /* is_block */);
2198                 }
2199                 if (error)
2200                         return error;
2201         }
2202         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2203         if (!IS_LAST_ENTRY(s->first)) {
2204                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2205                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2206         } else {
2207                 header->h_magic = cpu_to_le32(0);
2208                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2209         }
2210         return 0;
2211 }
2212
2213 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2214                                 struct ext4_xattr_info *i,
2215                                 struct ext4_xattr_ibody_find *is)
2216 {
2217         struct ext4_xattr_ibody_header *header;
2218         struct ext4_xattr_search *s = &is->s;
2219         int error;
2220
2221         if (EXT4_I(inode)->i_extra_isize == 0)
2222                 return -ENOSPC;
2223         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2224         if (error)
2225                 return error;
2226         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2227         if (!IS_LAST_ENTRY(s->first)) {
2228                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2229                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2230         } else {
2231                 header->h_magic = cpu_to_le32(0);
2232                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2233         }
2234         return 0;
2235 }
2236
2237 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2238                                  struct ext4_xattr_info *i)
2239 {
2240         void *value;
2241
2242         /* When e_value_inum is set the value is stored externally. */
2243         if (s->here->e_value_inum)
2244                 return 0;
2245         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2246                 return 0;
2247         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2248         return !memcmp(value, i->value, i->value_len);
2249 }
2250
2251 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2252 {
2253         struct buffer_head *bh;
2254         int error;
2255
2256         if (!EXT4_I(inode)->i_file_acl)
2257                 return NULL;
2258         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2259         if (!bh)
2260                 return ERR_PTR(-EIO);
2261         error = ext4_xattr_check_block(inode, bh);
2262         if (error)
2263                 return ERR_PTR(error);
2264         return bh;
2265 }
2266
2267 /*
2268  * ext4_xattr_set_handle()
2269  *
2270  * Create, replace or remove an extended attribute for this inode.  Value
2271  * is NULL to remove an existing extended attribute, and non-NULL to
2272  * either replace an existing extended attribute, or create a new extended
2273  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2274  * specify that an extended attribute must exist and must not exist
2275  * previous to the call, respectively.
2276  *
2277  * Returns 0, or a negative error number on failure.
2278  */
2279 int
2280 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2281                       const char *name, const void *value, size_t value_len,
2282                       int flags)
2283 {
2284         struct ext4_xattr_info i = {
2285                 .name_index = name_index,
2286                 .name = name,
2287                 .value = value,
2288                 .value_len = value_len,
2289                 .in_inode = 0,
2290         };
2291         struct ext4_xattr_ibody_find is = {
2292                 .s = { .not_found = -ENODATA, },
2293         };
2294         struct ext4_xattr_block_find bs = {
2295                 .s = { .not_found = -ENODATA, },
2296         };
2297         int no_expand;
2298         int error;
2299
2300         if (!name)
2301                 return -EINVAL;
2302         if (strlen(name) > 255)
2303                 return -ERANGE;
2304
2305         ext4_write_lock_xattr(inode, &no_expand);
2306
2307         /* Check journal credits under write lock. */
2308         if (ext4_handle_valid(handle)) {
2309                 struct buffer_head *bh;
2310                 int credits;
2311
2312                 bh = ext4_xattr_get_block(inode);
2313                 if (IS_ERR(bh)) {
2314                         error = PTR_ERR(bh);
2315                         goto cleanup;
2316                 }
2317
2318                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2319                                                    value_len,
2320                                                    flags & XATTR_CREATE);
2321                 brelse(bh);
2322
2323                 if (!ext4_handle_has_enough_credits(handle, credits)) {
2324                         error = -ENOSPC;
2325                         goto cleanup;
2326                 }
2327         }
2328
2329         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2330         if (error)
2331                 goto cleanup;
2332
2333         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2334                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2335                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2336                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2337         }
2338
2339         error = ext4_xattr_ibody_find(inode, &i, &is);
2340         if (error)
2341                 goto cleanup;
2342         if (is.s.not_found)
2343                 error = ext4_xattr_block_find(inode, &i, &bs);
2344         if (error)
2345                 goto cleanup;
2346         if (is.s.not_found && bs.s.not_found) {
2347                 error = -ENODATA;
2348                 if (flags & XATTR_REPLACE)
2349                         goto cleanup;
2350                 error = 0;
2351                 if (!value)
2352                         goto cleanup;
2353         } else {
2354                 error = -EEXIST;
2355                 if (flags & XATTR_CREATE)
2356                         goto cleanup;
2357         }
2358
2359         if (!value) {
2360                 if (!is.s.not_found)
2361                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2362                 else if (!bs.s.not_found)
2363                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2364         } else {
2365                 error = 0;
2366                 /* Xattr value did not change? Save us some work and bail out */
2367                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2368                         goto cleanup;
2369                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2370                         goto cleanup;
2371
2372                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2373                     (EXT4_XATTR_SIZE(i.value_len) >
2374                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2375                         i.in_inode = 1;
2376 retry_inode:
2377                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2378                 if (!error && !bs.s.not_found) {
2379                         i.value = NULL;
2380                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2381                 } else if (error == -ENOSPC) {
2382                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2383                                 error = ext4_xattr_block_find(inode, &i, &bs);
2384                                 if (error)
2385                                         goto cleanup;
2386                         }
2387                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2388                         if (!error && !is.s.not_found) {
2389                                 i.value = NULL;
2390                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2391                                                              &is);
2392                         } else if (error == -ENOSPC) {
2393                                 /*
2394                                  * Xattr does not fit in the block, store at
2395                                  * external inode if possible.
2396                                  */
2397                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2398                                     !i.in_inode) {
2399                                         i.in_inode = 1;
2400                                         goto retry_inode;
2401                                 }
2402                         }
2403                 }
2404         }
2405         if (!error) {
2406                 ext4_xattr_update_super_block(handle, inode->i_sb);
2407                 inode->i_ctime = current_time(inode);
2408                 if (!value)
2409                         no_expand = 0;
2410                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2411                 /*
2412                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2413                  * error != 0.
2414                  */
2415                 is.iloc.bh = NULL;
2416                 if (IS_SYNC(inode))
2417                         ext4_handle_sync(handle);
2418         }
2419
2420 cleanup:
2421         brelse(is.iloc.bh);
2422         brelse(bs.bh);
2423         ext4_write_unlock_xattr(inode, &no_expand);
2424         return error;
2425 }
2426
2427 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2428                            bool is_create, int *credits)
2429 {
2430         struct buffer_head *bh;
2431         int err;
2432
2433         *credits = 0;
2434
2435         if (!EXT4_SB(inode->i_sb)->s_journal)
2436                 return 0;
2437
2438         down_read(&EXT4_I(inode)->xattr_sem);
2439
2440         bh = ext4_xattr_get_block(inode);
2441         if (IS_ERR(bh)) {
2442                 err = PTR_ERR(bh);
2443         } else {
2444                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2445                                                     value_len, is_create);
2446                 brelse(bh);
2447                 err = 0;
2448         }
2449
2450         up_read(&EXT4_I(inode)->xattr_sem);
2451         return err;
2452 }
2453
2454 /*
2455  * ext4_xattr_set()
2456  *
2457  * Like ext4_xattr_set_handle, but start from an inode. This extended
2458  * attribute modification is a filesystem transaction by itself.
2459  *
2460  * Returns 0, or a negative error number on failure.
2461  */
2462 int
2463 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2464                const void *value, size_t value_len, int flags)
2465 {
2466         handle_t *handle;
2467         struct super_block *sb = inode->i_sb;
2468         int error, retries = 0;
2469         int credits;
2470
2471         error = dquot_initialize(inode);
2472         if (error)
2473                 return error;
2474
2475 retry:
2476         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2477                                        &credits);
2478         if (error)
2479                 return error;
2480
2481         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2482         if (IS_ERR(handle)) {
2483                 error = PTR_ERR(handle);
2484         } else {
2485                 int error2;
2486
2487                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2488                                               value, value_len, flags);
2489                 error2 = ext4_journal_stop(handle);
2490                 if (error == -ENOSPC &&
2491                     ext4_should_retry_alloc(sb, &retries))
2492                         goto retry;
2493                 if (error == 0)
2494                         error = error2;
2495         }
2496
2497         return error;
2498 }
2499
2500 /*
2501  * Shift the EA entries in the inode to create space for the increased
2502  * i_extra_isize.
2503  */
2504 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2505                                      int value_offs_shift, void *to,
2506                                      void *from, size_t n)
2507 {
2508         struct ext4_xattr_entry *last = entry;
2509         int new_offs;
2510
2511         /* We always shift xattr headers further thus offsets get lower */
2512         BUG_ON(value_offs_shift > 0);
2513
2514         /* Adjust the value offsets of the entries */
2515         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2516                 if (!last->e_value_inum && last->e_value_size) {
2517                         new_offs = le16_to_cpu(last->e_value_offs) +
2518                                                         value_offs_shift;
2519                         last->e_value_offs = cpu_to_le16(new_offs);
2520                 }
2521         }
2522         /* Shift the entries by n bytes */
2523         memmove(to, from, n);
2524 }
2525
2526 /*
2527  * Move xattr pointed to by 'entry' from inode into external xattr block
2528  */
2529 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2530                                     struct ext4_inode *raw_inode,
2531                                     struct ext4_xattr_entry *entry)
2532 {
2533         struct ext4_xattr_ibody_find *is = NULL;
2534         struct ext4_xattr_block_find *bs = NULL;
2535         char *buffer = NULL, *b_entry_name = NULL;
2536         size_t value_size = le32_to_cpu(entry->e_value_size);
2537         struct ext4_xattr_info i = {
2538                 .value = NULL,
2539                 .value_len = 0,
2540                 .name_index = entry->e_name_index,
2541                 .in_inode = !!entry->e_value_inum,
2542         };
2543         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2544         int error;
2545
2546         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2547         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2548         buffer = kmalloc(value_size, GFP_NOFS);
2549         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2550         if (!is || !bs || !buffer || !b_entry_name) {
2551                 error = -ENOMEM;
2552                 goto out;
2553         }
2554
2555         is->s.not_found = -ENODATA;
2556         bs->s.not_found = -ENODATA;
2557         is->iloc.bh = NULL;
2558         bs->bh = NULL;
2559
2560         /* Save the entry name and the entry value */
2561         if (entry->e_value_inum) {
2562                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2563                 if (error)
2564                         goto out;
2565         } else {
2566                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2567                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2568         }
2569
2570         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2571         b_entry_name[entry->e_name_len] = '\0';
2572         i.name = b_entry_name;
2573
2574         error = ext4_get_inode_loc(inode, &is->iloc);
2575         if (error)
2576                 goto out;
2577
2578         error = ext4_xattr_ibody_find(inode, &i, is);
2579         if (error)
2580                 goto out;
2581
2582         /* Remove the chosen entry from the inode */
2583         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2584         if (error)
2585                 goto out;
2586
2587         i.value = buffer;
2588         i.value_len = value_size;
2589         error = ext4_xattr_block_find(inode, &i, bs);
2590         if (error)
2591                 goto out;
2592
2593         /* Add entry which was removed from the inode into the block */
2594         error = ext4_xattr_block_set(handle, inode, &i, bs);
2595         if (error)
2596                 goto out;
2597         error = 0;
2598 out:
2599         kfree(b_entry_name);
2600         kfree(buffer);
2601         if (is)
2602                 brelse(is->iloc.bh);
2603         kfree(is);
2604         kfree(bs);
2605
2606         return error;
2607 }
2608
2609 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2610                                        struct ext4_inode *raw_inode,
2611                                        int isize_diff, size_t ifree,
2612                                        size_t bfree, int *total_ino)
2613 {
2614         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2615         struct ext4_xattr_entry *small_entry;
2616         struct ext4_xattr_entry *entry;
2617         struct ext4_xattr_entry *last;
2618         unsigned int entry_size;        /* EA entry size */
2619         unsigned int total_size;        /* EA entry size + value size */
2620         unsigned int min_total_size;
2621         int error;
2622
2623         while (isize_diff > ifree) {
2624                 entry = NULL;
2625                 small_entry = NULL;
2626                 min_total_size = ~0U;
2627                 last = IFIRST(header);
2628                 /* Find the entry best suited to be pushed into EA block */
2629                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2630                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2631                         if (!last->e_value_inum)
2632                                 total_size += EXT4_XATTR_SIZE(
2633                                                le32_to_cpu(last->e_value_size));
2634                         if (total_size <= bfree &&
2635                             total_size < min_total_size) {
2636                                 if (total_size + ifree < isize_diff) {
2637                                         small_entry = last;
2638                                 } else {
2639                                         entry = last;
2640                                         min_total_size = total_size;
2641                                 }
2642                         }
2643                 }
2644
2645                 if (entry == NULL) {
2646                         if (small_entry == NULL)
2647                                 return -ENOSPC;
2648                         entry = small_entry;
2649                 }
2650
2651                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2652                 total_size = entry_size;
2653                 if (!entry->e_value_inum)
2654                         total_size += EXT4_XATTR_SIZE(
2655                                               le32_to_cpu(entry->e_value_size));
2656                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2657                                                  entry);
2658                 if (error)
2659                         return error;
2660
2661                 *total_ino -= entry_size;
2662                 ifree += total_size;
2663                 bfree -= total_size;
2664         }
2665
2666         return 0;
2667 }
2668
2669 /*
2670  * Expand an inode by new_extra_isize bytes when EAs are present.
2671  * Returns 0 on success or negative error number on failure.
2672  */
2673 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2674                                struct ext4_inode *raw_inode, handle_t *handle)
2675 {
2676         struct ext4_xattr_ibody_header *header;
2677         struct buffer_head *bh;
2678         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2679         static unsigned int mnt_count;
2680         size_t min_offs;
2681         size_t ifree, bfree;
2682         int total_ino;
2683         void *base, *end;
2684         int error = 0, tried_min_extra_isize = 0;
2685         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2686         int isize_diff; /* How much do we need to grow i_extra_isize */
2687
2688 retry:
2689         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2690         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2691                 return 0;
2692
2693         header = IHDR(inode, raw_inode);
2694
2695         /*
2696          * Check if enough free space is available in the inode to shift the
2697          * entries ahead by new_extra_isize.
2698          */
2699
2700         base = IFIRST(header);
2701         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2702         min_offs = end - base;
2703         total_ino = sizeof(struct ext4_xattr_ibody_header);
2704
2705         error = xattr_check_inode(inode, header, end);
2706         if (error)
2707                 goto cleanup;
2708
2709         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2710         if (ifree >= isize_diff)
2711                 goto shift;
2712
2713         /*
2714          * Enough free space isn't available in the inode, check if
2715          * EA block can hold new_extra_isize bytes.
2716          */
2717         if (EXT4_I(inode)->i_file_acl) {
2718                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2719                 error = -EIO;
2720                 if (!bh)
2721                         goto cleanup;
2722                 if (ext4_xattr_check_block(inode, bh)) {
2723                         EXT4_ERROR_INODE(inode, "bad block %llu",
2724                                          EXT4_I(inode)->i_file_acl);
2725                         error = -EFSCORRUPTED;
2726                         brelse(bh);
2727                         goto cleanup;
2728                 }
2729                 base = BHDR(bh);
2730                 end = bh->b_data + bh->b_size;
2731                 min_offs = end - base;
2732                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2733                                               NULL);
2734                 brelse(bh);
2735                 if (bfree + ifree < isize_diff) {
2736                         if (!tried_min_extra_isize && s_min_extra_isize) {
2737                                 tried_min_extra_isize++;
2738                                 new_extra_isize = s_min_extra_isize;
2739                                 goto retry;
2740                         }
2741                         error = -ENOSPC;
2742                         goto cleanup;
2743                 }
2744         } else {
2745                 bfree = inode->i_sb->s_blocksize;
2746         }
2747
2748         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2749                                             isize_diff, ifree, bfree,
2750                                             &total_ino);
2751         if (error) {
2752                 if (error == -ENOSPC && !tried_min_extra_isize &&
2753                     s_min_extra_isize) {
2754                         tried_min_extra_isize++;
2755                         new_extra_isize = s_min_extra_isize;
2756                         goto retry;
2757                 }
2758                 goto cleanup;
2759         }
2760 shift:
2761         /* Adjust the offsets and shift the remaining entries ahead */
2762         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2763                         - new_extra_isize, (void *)raw_inode +
2764                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2765                         (void *)header, total_ino);
2766         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2767
2768 cleanup:
2769         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2770                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2771                              inode->i_ino);
2772                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2773         }
2774         return error;
2775 }
2776
2777 #define EIA_INCR 16 /* must be 2^n */
2778 #define EIA_MASK (EIA_INCR - 1)
2779
2780 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2781  * If @ea_inode_array is new or full it will be grown and the old
2782  * contents copied over.
2783  */
2784 static int
2785 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2786                         struct inode *inode)
2787 {
2788         if (*ea_inode_array == NULL) {
2789                 /*
2790                  * Start with 15 inodes, so it fits into a power-of-two size.
2791                  * If *ea_inode_array is NULL, this is essentially offsetof()
2792                  */
2793                 (*ea_inode_array) =
2794                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2795                                          inodes[EIA_MASK]),
2796                                 GFP_NOFS);
2797                 if (*ea_inode_array == NULL)
2798                         return -ENOMEM;
2799                 (*ea_inode_array)->count = 0;
2800         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2801                 /* expand the array once all 15 + n * 16 slots are full */
2802                 struct ext4_xattr_inode_array *new_array = NULL;
2803                 int count = (*ea_inode_array)->count;
2804
2805                 /* if new_array is NULL, this is essentially offsetof() */
2806                 new_array = kmalloc(
2807                                 offsetof(struct ext4_xattr_inode_array,
2808                                          inodes[count + EIA_INCR]),
2809                                 GFP_NOFS);
2810                 if (new_array == NULL)
2811                         return -ENOMEM;
2812                 memcpy(new_array, *ea_inode_array,
2813                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2814                 kfree(*ea_inode_array);
2815                 *ea_inode_array = new_array;
2816         }
2817         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2818         return 0;
2819 }
2820
2821 /*
2822  * ext4_xattr_delete_inode()
2823  *
2824  * Free extended attribute resources associated with this inode. Traverse
2825  * all entries and decrement reference on any xattr inodes associated with this
2826  * inode. This is called immediately before an inode is freed. We have exclusive
2827  * access to the inode. If an orphan inode is deleted it will also release its
2828  * references on xattr block and xattr inodes.
2829  */
2830 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2831                             struct ext4_xattr_inode_array **ea_inode_array,
2832                             int extra_credits)
2833 {
2834         struct buffer_head *bh = NULL;
2835         struct ext4_xattr_ibody_header *header;
2836         struct ext4_iloc iloc = { .bh = NULL };
2837         struct ext4_xattr_entry *entry;
2838         struct inode *ea_inode;
2839         int error;
2840
2841         error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
2842                                           NULL /* bh */,
2843                                           false /* dirty */,
2844                                           false /* block_csum */);
2845         if (error) {
2846                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2847                 goto cleanup;
2848         }
2849
2850         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2851             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2852
2853                 error = ext4_get_inode_loc(inode, &iloc);
2854                 if (error) {
2855                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2856                         goto cleanup;
2857                 }
2858
2859                 error = ext4_journal_get_write_access(handle, iloc.bh);
2860                 if (error) {
2861                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2862                                          error);
2863                         goto cleanup;
2864                 }
2865
2866                 header = IHDR(inode, ext4_raw_inode(&iloc));
2867                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2868                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2869                                                      IFIRST(header),
2870                                                      false /* block_csum */,
2871                                                      ea_inode_array,
2872                                                      extra_credits,
2873                                                      false /* skip_quota */);
2874         }
2875
2876         if (EXT4_I(inode)->i_file_acl) {
2877                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2878                 if (!bh) {
2879                         EXT4_ERROR_INODE(inode, "block %llu read error",
2880                                          EXT4_I(inode)->i_file_acl);
2881                         error = -EIO;
2882                         goto cleanup;
2883                 }
2884                 error = ext4_xattr_check_block(inode, bh);
2885                 if (error) {
2886                         EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
2887                                          EXT4_I(inode)->i_file_acl, error);
2888                         goto cleanup;
2889                 }
2890
2891                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2892                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2893                              entry = EXT4_XATTR_NEXT(entry)) {
2894                                 if (!entry->e_value_inum)
2895                                         continue;
2896                                 error = ext4_xattr_inode_iget(inode,
2897                                               le32_to_cpu(entry->e_value_inum),
2898                                               le32_to_cpu(entry->e_hash),
2899                                               &ea_inode);
2900                                 if (error)
2901                                         continue;
2902                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2903                                               le32_to_cpu(entry->e_value_size));
2904                                 iput(ea_inode);
2905                         }
2906
2907                 }
2908
2909                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2910                                          extra_credits);
2911                 /*
2912                  * Update i_file_acl value in the same transaction that releases
2913                  * block.
2914                  */
2915                 EXT4_I(inode)->i_file_acl = 0;
2916                 error = ext4_mark_inode_dirty(handle, inode);
2917                 if (error) {
2918                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2919                                          error);
2920                         goto cleanup;
2921                 }
2922         }
2923         error = 0;
2924 cleanup:
2925         brelse(iloc.bh);
2926         brelse(bh);
2927         return error;
2928 }
2929
2930 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2931 {
2932         int idx;
2933
2934         if (ea_inode_array == NULL)
2935                 return;
2936
2937         for (idx = 0; idx < ea_inode_array->count; ++idx)
2938                 iput(ea_inode_array->inodes[idx]);
2939         kfree(ea_inode_array);
2940 }
2941
2942 /*
2943  * ext4_xattr_block_cache_insert()
2944  *
2945  * Create a new entry in the extended attribute block cache, and insert
2946  * it unless such an entry is already in the cache.
2947  *
2948  * Returns 0, or a negative error number on failure.
2949  */
2950 static void
2951 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2952                               struct buffer_head *bh)
2953 {
2954         struct ext4_xattr_header *header = BHDR(bh);
2955         __u32 hash = le32_to_cpu(header->h_hash);
2956         int reusable = le32_to_cpu(header->h_refcount) <
2957                        EXT4_XATTR_REFCOUNT_MAX;
2958         int error;
2959
2960         if (!ea_block_cache)
2961                 return;
2962         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2963                                       bh->b_blocknr, reusable);
2964         if (error) {
2965                 if (error == -EBUSY)
2966                         ea_bdebug(bh, "already in cache");
2967         } else
2968                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2969 }
2970
2971 /*
2972  * ext4_xattr_cmp()
2973  *
2974  * Compare two extended attribute blocks for equality.
2975  *
2976  * Returns 0 if the blocks are equal, 1 if they differ, and
2977  * a negative error number on errors.
2978  */
2979 static int
2980 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2981                struct ext4_xattr_header *header2)
2982 {
2983         struct ext4_xattr_entry *entry1, *entry2;
2984
2985         entry1 = ENTRY(header1+1);
2986         entry2 = ENTRY(header2+1);
2987         while (!IS_LAST_ENTRY(entry1)) {
2988                 if (IS_LAST_ENTRY(entry2))
2989                         return 1;
2990                 if (entry1->e_hash != entry2->e_hash ||
2991                     entry1->e_name_index != entry2->e_name_index ||
2992                     entry1->e_name_len != entry2->e_name_len ||
2993                     entry1->e_value_size != entry2->e_value_size ||
2994                     entry1->e_value_inum != entry2->e_value_inum ||
2995                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2996                         return 1;
2997                 if (!entry1->e_value_inum &&
2998                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
2999                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3000                            le32_to_cpu(entry1->e_value_size)))
3001                         return 1;
3002
3003                 entry1 = EXT4_XATTR_NEXT(entry1);
3004                 entry2 = EXT4_XATTR_NEXT(entry2);
3005         }
3006         if (!IS_LAST_ENTRY(entry2))
3007                 return 1;
3008         return 0;
3009 }
3010
3011 /*
3012  * ext4_xattr_block_cache_find()
3013  *
3014  * Find an identical extended attribute block.
3015  *
3016  * Returns a pointer to the block found, or NULL if such a block was
3017  * not found or an error occurred.
3018  */
3019 static struct buffer_head *
3020 ext4_xattr_block_cache_find(struct inode *inode,
3021                             struct ext4_xattr_header *header,
3022                             struct mb_cache_entry **pce)
3023 {
3024         __u32 hash = le32_to_cpu(header->h_hash);
3025         struct mb_cache_entry *ce;
3026         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3027
3028         if (!ea_block_cache)
3029                 return NULL;
3030         if (!header->h_hash)
3031                 return NULL;  /* never share */
3032         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3033         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3034         while (ce) {
3035                 struct buffer_head *bh;
3036
3037                 bh = sb_bread(inode->i_sb, ce->e_value);
3038                 if (!bh) {
3039                         EXT4_ERROR_INODE(inode, "block %lu read error",
3040                                          (unsigned long)ce->e_value);
3041                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3042                         *pce = ce;
3043                         return bh;
3044                 }
3045                 brelse(bh);
3046                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3047         }
3048         return NULL;
3049 }
3050
3051 #define NAME_HASH_SHIFT 5
3052 #define VALUE_HASH_SHIFT 16
3053
3054 /*
3055  * ext4_xattr_hash_entry()
3056  *
3057  * Compute the hash of an extended attribute.
3058  */
3059 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3060                                     size_t value_count)
3061 {
3062         __u32 hash = 0;
3063
3064         while (name_len--) {
3065                 hash = (hash << NAME_HASH_SHIFT) ^
3066                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3067                        *name++;
3068         }
3069         while (value_count--) {
3070                 hash = (hash << VALUE_HASH_SHIFT) ^
3071                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3072                        le32_to_cpu(*value++);
3073         }
3074         return cpu_to_le32(hash);
3075 }
3076
3077 #undef NAME_HASH_SHIFT
3078 #undef VALUE_HASH_SHIFT
3079
3080 #define BLOCK_HASH_SHIFT 16
3081
3082 /*
3083  * ext4_xattr_rehash()
3084  *
3085  * Re-compute the extended attribute hash value after an entry has changed.
3086  */
3087 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3088 {
3089         struct ext4_xattr_entry *here;
3090         __u32 hash = 0;
3091
3092         here = ENTRY(header+1);
3093         while (!IS_LAST_ENTRY(here)) {
3094                 if (!here->e_hash) {
3095                         /* Block is not shared if an entry's hash value == 0 */
3096                         hash = 0;
3097                         break;
3098                 }
3099                 hash = (hash << BLOCK_HASH_SHIFT) ^
3100                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3101                        le32_to_cpu(here->e_hash);
3102                 here = EXT4_XATTR_NEXT(here);
3103         }
3104         header->h_hash = cpu_to_le32(hash);
3105 }
3106
3107 #undef BLOCK_HASH_SHIFT
3108
3109 #define HASH_BUCKET_BITS        10
3110
3111 struct mb_cache *
3112 ext4_xattr_create_cache(void)
3113 {
3114         return mb_cache_create(HASH_BUCKET_BITS);
3115 }
3116
3117 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3118 {
3119         if (cache)
3120                 mb_cache_destroy(cache);
3121 }
3122