fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   5  *
   6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   7  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  13  *  and Andreas Gruenbacher <agruen@suse.de>.
  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 <linux/rwsem.h>
  59 #include "ext4_jbd2.h"
  60 #include "ext4.h"
  61 #include "xattr.h"
  62 #include "acl.h"
  63
  64 #ifdef EXT4_XATTR_DEBUG
  65 # define ea_idebug(inode, f...) do { \
  66                 printk(KERN_DEBUG "inode %s:%lu: ", \
  67                         inode->i_sb->s_id, inode->i_ino); \
  68                 printk(f); \
  69                 printk("\n"); \
  70         } while (0)
  71 # define ea_bdebug(bh, f...) do { \
  72                 char b[BDEVNAME_SIZE]; \
  73                 printk(KERN_DEBUG "block %s:%lu: ", \
  74                         bdevname(bh->b_bdev, b), \
  75                         (unsigned long) bh->b_blocknr); \
  76                 printk(f); \
  77                 printk("\n"); \
  78         } while (0)
  79 #else
  80 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  81 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  82 #endif
  83
  84 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
  85 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  86                                                  struct ext4_xattr_header *,
  87                                                  struct mb_cache_entry **);
  88 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  89                               struct ext4_xattr_entry *);
  90 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  91                            size_t buffer_size);
  92
  93 static const struct xattr_handler *ext4_xattr_handler_map[] = {
  94         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  95 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  96         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  97         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  98 #endif
  99         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 100 #ifdef CONFIG_EXT4_FS_SECURITY
 101         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 102 #endif
 103 };
 104
 105 const struct xattr_handler *ext4_xattr_handlers[] = {
 106         &ext4_xattr_user_handler,
 107         &ext4_xattr_trusted_handler,
 108 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 109         &posix_acl_access_xattr_handler,
 110         &posix_acl_default_xattr_handler,
 111 #endif
 112 #ifdef CONFIG_EXT4_FS_SECURITY
 113         &ext4_xattr_security_handler,
 114 #endif
 115         NULL
 116 };
 117
 118 #define EXT4_GET_MB_CACHE(inode)        (((struct ext4_sb_info *) \
 119                                 inode->i_sb->s_fs_info)->s_mb_cache)
 120
 121 static __le32 ext4_xattr_block_csum(struct inode *inode,
 122                                     sector_t block_nr,
 123                                     struct ext4_xattr_header *hdr)
 124 {
 125         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 126         __u32 csum;
 127         __le32 save_csum;
 128         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 129
 130         save_csum = hdr->h_checksum;
 131         hdr->h_checksum = 0;
 132         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 133                            sizeof(dsk_block_nr));
 134         csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
 135                            EXT4_BLOCK_SIZE(inode->i_sb));
 136
 137         hdr->h_checksum = save_csum;
 138         return cpu_to_le32(csum);
 139 }
 140
 141 static int ext4_xattr_block_csum_verify(struct inode *inode,
 142                                         sector_t block_nr,
 143                                         struct ext4_xattr_header *hdr)
 144 {
 145         if (ext4_has_metadata_csum(inode->i_sb) &&
 146             (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 147                 return 0;
 148         return 1;
 149 }
 150
 151 static void ext4_xattr_block_csum_set(struct inode *inode,
 152                                       sector_t block_nr,
 153                                       struct ext4_xattr_header *hdr)
 154 {
 155         if (!ext4_has_metadata_csum(inode->i_sb))
 156                 return;
 157
 158         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 159 }
 160
 161 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 162                                                 struct inode *inode,
 163                                                 struct buffer_head *bh)
 164 {
 165         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 166         return ext4_handle_dirty_metadata(handle, inode, bh);
 167 }
 168
 169 static inline const struct xattr_handler *
 170 ext4_xattr_handler(int name_index)
 171 {
 172         const struct xattr_handler *handler = NULL;
 173
 174         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 175                 handler = ext4_xattr_handler_map[name_index];
 176         return handler;
 177 }
 178
 179 /*
 180  * Inode operation listxattr()
 181  *
 182  * dentry->d_inode->i_mutex: don't care
 183  */
 184 ssize_t
 185 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 186 {
 187         return ext4_xattr_list(dentry, buffer, size);
 188 }
 189
 190 static int
 191 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
 192                        void *value_start)
 193 {
 194         struct ext4_xattr_entry *e = entry;
 195
 196         while (!IS_LAST_ENTRY(e)) {
 197                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 198                 if ((void *)next >= end)
 199                         return -EIO;
 200                 e = next;
 201         }
 202
 203         while (!IS_LAST_ENTRY(entry)) {
 204                 if (entry->e_value_size != 0 &&
 205                     (value_start + le16_to_cpu(entry->e_value_offs) <
 206                      (void *)e + sizeof(__u32) ||
 207                      value_start + le16_to_cpu(entry->e_value_offs) +
 208                     le32_to_cpu(entry->e_value_size) > end))
 209                         return -EIO;
 210                 entry = EXT4_XATTR_NEXT(entry);
 211         }
 212
 213         return 0;
 214 }
 215
 216 static inline int
 217 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 218 {
 219         int error;
 220
 221         if (buffer_verified(bh))
 222                 return 0;
 223
 224         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 225             BHDR(bh)->h_blocks != cpu_to_le32(1))
 226                 return -EIO;
 227         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 228                 return -EIO;
 229         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
 230                                        bh->b_data);
 231         if (!error)
 232                 set_buffer_verified(bh);
 233         return error;
 234 }
 235
 236 static inline int
 237 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 238 {
 239         size_t value_size = le32_to_cpu(entry->e_value_size);
 240
 241         if (entry->e_value_block != 0 || value_size > size ||
 242             le16_to_cpu(entry->e_value_offs) + value_size > size)
 243                 return -EIO;
 244         return 0;
 245 }
 246
 247 static int
 248 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 249                       const char *name, size_t size, int sorted)
 250 {
 251         struct ext4_xattr_entry *entry;
 252         size_t name_len;
 253         int cmp = 1;
 254
 255         if (name == NULL)
 256                 return -EINVAL;
 257         name_len = strlen(name);
 258         entry = *pentry;
 259         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 260                 cmp = name_index - entry->e_name_index;
 261                 if (!cmp)
 262                         cmp = name_len - entry->e_name_len;
 263                 if (!cmp)
 264                         cmp = memcmp(name, entry->e_name, name_len);
 265                 if (cmp <= 0 && (sorted || cmp == 0))
 266                         break;
 267         }
 268         *pentry = entry;
 269         if (!cmp && ext4_xattr_check_entry(entry, size))
 270                         return -EIO;
 271         return cmp ? -ENODATA : 0;
 272 }
 273
 274 static int
 275 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 276                      void *buffer, size_t buffer_size)
 277 {
 278         struct buffer_head *bh = NULL;
 279         struct ext4_xattr_entry *entry;
 280         size_t size;
 281         int error;
 282         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 283
 284         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 285                   name_index, name, buffer, (long)buffer_size);
 286
 287         error = -ENODATA;
 288         if (!EXT4_I(inode)->i_file_acl)
 289                 goto cleanup;
 290         ea_idebug(inode, "reading block %llu",
 291                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 292         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 293         if (!bh)
 294                 goto cleanup;
 295         ea_bdebug(bh, "b_count=%d, refcount=%d",
 296                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 297         if (ext4_xattr_check_block(inode, bh)) {
 298 bad_block:
 299                 EXT4_ERROR_INODE(inode, "bad block %llu",
 300                                  EXT4_I(inode)->i_file_acl);
 301                 error = -EIO;
 302                 goto cleanup;
 303         }
 304         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 305         entry = BFIRST(bh);
 306         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 307         if (error == -EIO)
 308                 goto bad_block;
 309         if (error)
 310                 goto cleanup;
 311         size = le32_to_cpu(entry->e_value_size);
 312         if (buffer) {
 313                 error = -ERANGE;
 314                 if (size > buffer_size)
 315                         goto cleanup;
 316                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 317                        size);
 318         }
 319         error = size;
 320
 321 cleanup:
 322         brelse(bh);
 323         return error;
 324 }
 325
 326 int
 327 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 328                      void *buffer, size_t buffer_size)
 329 {
 330         struct ext4_xattr_ibody_header *header;
 331         struct ext4_xattr_entry *entry;
 332         struct ext4_inode *raw_inode;
 333         struct ext4_iloc iloc;
 334         size_t size;
 335         void *end;
 336         int error;
 337
 338         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 339                 return -ENODATA;
 340         error = ext4_get_inode_loc(inode, &iloc);
 341         if (error)
 342                 return error;
 343         raw_inode = ext4_raw_inode(&iloc);
 344         header = IHDR(inode, raw_inode);
 345         entry = IFIRST(header);
 346         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 347         error = ext4_xattr_check_names(entry, end, entry);
 348         if (error)
 349                 goto cleanup;
 350         error = ext4_xattr_find_entry(&entry, name_index, name,
 351                                       end - (void *)entry, 0);
 352         if (error)
 353                 goto cleanup;
 354         size = le32_to_cpu(entry->e_value_size);
 355         if (buffer) {
 356                 error = -ERANGE;
 357                 if (size > buffer_size)
 358                         goto cleanup;
 359                 memcpy(buffer, (void *)IFIRST(header) +
 360                        le16_to_cpu(entry->e_value_offs), size);
 361         }
 362         error = size;
 363
 364 cleanup:
 365         brelse(iloc.bh);
 366         return error;
 367 }
 368
 369 /*
 370  * ext4_xattr_get()
 371  *
 372  * Copy an extended attribute into the buffer
 373  * provided, or compute the buffer size required.
 374  * Buffer is NULL to compute the size of the buffer required.
 375  *
 376  * Returns a negative error number on failure, or the number of bytes
 377  * used / required on success.
 378  */
 379 int
 380 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 381                void *buffer, size_t buffer_size)
 382 {
 383         int error;
 384
 385         if (strlen(name) > 255)
 386                 return -ERANGE;
 387
 388         down_read(&EXT4_I(inode)->xattr_sem);
 389         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 390                                      buffer_size);
 391         if (error == -ENODATA)
 392                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 393                                              buffer_size);
 394         up_read(&EXT4_I(inode)->xattr_sem);
 395         return error;
 396 }
 397
 398 static int
 399 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 400                         char *buffer, size_t buffer_size)
 401 {
 402         size_t rest = buffer_size;
 403
 404         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 405                 const struct xattr_handler *handler =
 406                         ext4_xattr_handler(entry->e_name_index);
 407
 408                 if (handler) {
 409                         size_t size = handler->list(dentry, buffer, rest,
 410                                                     entry->e_name,
 411                                                     entry->e_name_len,
 412                                                     handler->flags);
 413                         if (buffer) {
 414                                 if (size > rest)
 415                                         return -ERANGE;
 416                                 buffer += size;
 417                         }
 418                         rest -= size;
 419                 }
 420         }
 421         return buffer_size - rest;
 422 }
 423
 424 static int
 425 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 426 {
 427         struct inode *inode = dentry->d_inode;
 428         struct buffer_head *bh = NULL;
 429         int error;
 430         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 431
 432         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 433                   buffer, (long)buffer_size);
 434
 435         error = 0;
 436         if (!EXT4_I(inode)->i_file_acl)
 437                 goto cleanup;
 438         ea_idebug(inode, "reading block %llu",
 439                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 440         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 441         error = -EIO;
 442         if (!bh)
 443                 goto cleanup;
 444         ea_bdebug(bh, "b_count=%d, refcount=%d",
 445                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 446         if (ext4_xattr_check_block(inode, bh)) {
 447                 EXT4_ERROR_INODE(inode, "bad block %llu",
 448                                  EXT4_I(inode)->i_file_acl);
 449                 error = -EIO;
 450                 goto cleanup;
 451         }
 452         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 453         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 454
 455 cleanup:
 456         brelse(bh);
 457
 458         return error;
 459 }
 460
 461 static int
 462 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 463 {
 464         struct inode *inode = dentry->d_inode;
 465         struct ext4_xattr_ibody_header *header;
 466         struct ext4_inode *raw_inode;
 467         struct ext4_iloc iloc;
 468         void *end;
 469         int error;
 470
 471         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 472                 return 0;
 473         error = ext4_get_inode_loc(inode, &iloc);
 474         if (error)
 475                 return error;
 476         raw_inode = ext4_raw_inode(&iloc);
 477         header = IHDR(inode, raw_inode);
 478         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 479         error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
 480         if (error)
 481                 goto cleanup;
 482         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 483                                         buffer, buffer_size);
 484
 485 cleanup:
 486         brelse(iloc.bh);
 487         return error;
 488 }
 489
 490 /*
 491  * ext4_xattr_list()
 492  *
 493  * Copy a list of attribute names into the buffer
 494  * provided, or compute the buffer size required.
 495  * Buffer is NULL to compute the size of the buffer required.
 496  *
 497  * Returns a negative error number on failure, or the number of bytes
 498  * used / required on success.
 499  */
 500 static int
 501 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 502 {
 503         int ret, ret2;
 504
 505         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 506         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 507         if (ret < 0)
 508                 goto errout;
 509         if (buffer) {
 510                 buffer += ret;
 511                 buffer_size -= ret;
 512         }
 513         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 514         if (ret < 0)
 515                 goto errout;
 516         ret += ret2;
 517 errout:
 518         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 519         return ret;
 520 }
 521
 522 /*
 523  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 524  * not set, set it.
 525  */
 526 static void ext4_xattr_update_super_block(handle_t *handle,
 527                                           struct super_block *sb)
 528 {
 529         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 530                 return;
 531
 532         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 533         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 534                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 535                 ext4_handle_dirty_super(handle, sb);
 536         }
 537 }
 538
 539 /*
 540  * Release the xattr block BH: If the reference count is > 1, decrement it;
 541  * otherwise free the block.
 542  */
 543 static void
 544 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 545                          struct buffer_head *bh)
 546 {
 547         struct mb_cache_entry *ce = NULL;
 548         int error = 0;
 549         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 550
 551         ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
 552         BUFFER_TRACE(bh, "get_write_access");
 553         error = ext4_journal_get_write_access(handle, bh);
 554         if (error)
 555                 goto out;
 556
 557         lock_buffer(bh);
 558         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 559                 ea_bdebug(bh, "refcount now=0; freeing");
 560                 if (ce)
 561                         mb_cache_entry_free(ce);
 562                 get_bh(bh);
 563                 unlock_buffer(bh);
 564                 ext4_free_blocks(handle, inode, bh, 0, 1,
 565                                  EXT4_FREE_BLOCKS_METADATA |
 566                                  EXT4_FREE_BLOCKS_FORGET);
 567         } else {
 568                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 569                 if (ce)
 570                         mb_cache_entry_release(ce);
 571                 /*
 572                  * Beware of this ugliness: Releasing of xattr block references
 573                  * from different inodes can race and so we have to protect
 574                  * from a race where someone else frees the block (and releases
 575                  * its journal_head) before we are done dirtying the buffer. In
 576                  * nojournal mode this race is harmless and we actually cannot
 577                  * call ext4_handle_dirty_xattr_block() with locked buffer as
 578                  * that function can call sync_dirty_buffer() so for that case
 579                  * we handle the dirtying after unlocking the buffer.
 580                  */
 581                 if (ext4_handle_valid(handle))
 582                         error = ext4_handle_dirty_xattr_block(handle, inode,
 583                                                               bh);
 584                 unlock_buffer(bh);
 585                 if (!ext4_handle_valid(handle))
 586                         error = ext4_handle_dirty_xattr_block(handle, inode,
 587                                                               bh);
 588                 if (IS_SYNC(inode))
 589                         ext4_handle_sync(handle);
 590                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 591                 ea_bdebug(bh, "refcount now=%d; releasing",
 592                           le32_to_cpu(BHDR(bh)->h_refcount));
 593         }
 594 out:
 595         ext4_std_error(inode->i_sb, error);
 596         return;
 597 }
 598
 599 /*
 600  * Find the available free space for EAs. This also returns the total number of
 601  * bytes used by EA entries.
 602  */
 603 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 604                                     size_t *min_offs, void *base, int *total)
 605 {
 606         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 607                 if (!last->e_value_block && last->e_value_size) {
 608                         size_t offs = le16_to_cpu(last->e_value_offs);
 609                         if (offs < *min_offs)
 610                                 *min_offs = offs;
 611                 }
 612                 if (total)
 613                         *total += EXT4_XATTR_LEN(last->e_name_len);
 614         }
 615         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 616 }
 617
 618 static int
 619 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 620 {
 621         struct ext4_xattr_entry *last;
 622         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 623
 624         /* Compute min_offs and last. */
 625         last = s->first;
 626         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 627                 if (!last->e_value_block && last->e_value_size) {
 628                         size_t offs = le16_to_cpu(last->e_value_offs);
 629                         if (offs < min_offs)
 630                                 min_offs = offs;
 631                 }
 632         }
 633         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 634         if (!s->not_found) {
 635                 if (!s->here->e_value_block && s->here->e_value_size) {
 636                         size_t size = le32_to_cpu(s->here->e_value_size);
 637                         free += EXT4_XATTR_SIZE(size);
 638                 }
 639                 free += EXT4_XATTR_LEN(name_len);
 640         }
 641         if (i->value) {
 642                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 643                     free < EXT4_XATTR_LEN(name_len) +
 644                            EXT4_XATTR_SIZE(i->value_len))
 645                         return -ENOSPC;
 646         }
 647
 648         if (i->value && s->not_found) {
 649                 /* Insert the new name. */
 650                 size_t size = EXT4_XATTR_LEN(name_len);
 651                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 652                 memmove((void *)s->here + size, s->here, rest);
 653                 memset(s->here, 0, size);
 654                 s->here->e_name_index = i->name_index;
 655                 s->here->e_name_len = name_len;
 656                 memcpy(s->here->e_name, i->name, name_len);
 657         } else {
 658                 if (!s->here->e_value_block && s->here->e_value_size) {
 659                         void *first_val = s->base + min_offs;
 660                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 661                         void *val = s->base + offs;
 662                         size_t size = EXT4_XATTR_SIZE(
 663                                 le32_to_cpu(s->here->e_value_size));
 664
 665                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 666                                 /* The old and the new value have the same
 667                                    size. Just replace. */
 668                                 s->here->e_value_size =
 669                                         cpu_to_le32(i->value_len);
 670                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 671                                         memset(val, 0, size);
 672                                 } else {
 673                                         /* Clear pad bytes first. */
 674                                         memset(val + size - EXT4_XATTR_PAD, 0,
 675                                                EXT4_XATTR_PAD);
 676                                         memcpy(val, i->value, i->value_len);
 677                                 }
 678                                 return 0;
 679                         }
 680
 681                         /* Remove the old value. */
 682                         memmove(first_val + size, first_val, val - first_val);
 683                         memset(first_val, 0, size);
 684                         s->here->e_value_size = 0;
 685                         s->here->e_value_offs = 0;
 686                         min_offs += size;
 687
 688                         /* Adjust all value offsets. */
 689                         last = s->first;
 690                         while (!IS_LAST_ENTRY(last)) {
 691                                 size_t o = le16_to_cpu(last->e_value_offs);
 692                                 if (!last->e_value_block &&
 693                                     last->e_value_size && o < offs)
 694                                         last->e_value_offs =
 695                                                 cpu_to_le16(o + size);
 696                                 last = EXT4_XATTR_NEXT(last);
 697                         }
 698                 }
 699                 if (!i->value) {
 700                         /* Remove the old name. */
 701                         size_t size = EXT4_XATTR_LEN(name_len);
 702                         last = ENTRY((void *)last - size);
 703                         memmove(s->here, (void *)s->here + size,
 704                                 (void *)last - (void *)s->here + sizeof(__u32));
 705                         memset(last, 0, size);
 706                 }
 707         }
 708
 709         if (i->value) {
 710                 /* Insert the new value. */
 711                 s->here->e_value_size = cpu_to_le32(i->value_len);
 712                 if (i->value_len) {
 713                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 714                         void *val = s->base + min_offs - size;
 715                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 716                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 717                                 memset(val, 0, size);
 718                         } else {
 719                                 /* Clear the pad bytes first. */
 720                                 memset(val + size - EXT4_XATTR_PAD, 0,
 721                                        EXT4_XATTR_PAD);
 722                                 memcpy(val, i->value, i->value_len);
 723                         }
 724                 }
 725         }
 726         return 0;
 727 }
 728
 729 struct ext4_xattr_block_find {
 730         struct ext4_xattr_search s;
 731         struct buffer_head *bh;
 732 };
 733
 734 static int
 735 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 736                       struct ext4_xattr_block_find *bs)
 737 {
 738         struct super_block *sb = inode->i_sb;
 739         int error;
 740
 741         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 742                   i->name_index, i->name, i->value, (long)i->value_len);
 743
 744         if (EXT4_I(inode)->i_file_acl) {
 745                 /* The inode already has an extended attribute block. */
 746                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 747                 error = -EIO;
 748                 if (!bs->bh)
 749                         goto cleanup;
 750                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 751                         atomic_read(&(bs->bh->b_count)),
 752                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 753                 if (ext4_xattr_check_block(inode, bs->bh)) {
 754                         EXT4_ERROR_INODE(inode, "bad block %llu",
 755                                          EXT4_I(inode)->i_file_acl);
 756                         error = -EIO;
 757                         goto cleanup;
 758                 }
 759                 /* Find the named attribute. */
 760                 bs->s.base = BHDR(bs->bh);
 761                 bs->s.first = BFIRST(bs->bh);
 762                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 763                 bs->s.here = bs->s.first;
 764                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 765                                               i->name, bs->bh->b_size, 1);
 766                 if (error && error != -ENODATA)
 767                         goto cleanup;
 768                 bs->s.not_found = error;
 769         }
 770         error = 0;
 771
 772 cleanup:
 773         return error;
 774 }
 775
 776 static int
 777 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 778                      struct ext4_xattr_info *i,
 779                      struct ext4_xattr_block_find *bs)
 780 {
 781         struct super_block *sb = inode->i_sb;
 782         struct buffer_head *new_bh = NULL;
 783         struct ext4_xattr_search *s = &bs->s;
 784         struct mb_cache_entry *ce = NULL;
 785         int error = 0;
 786         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 787
 788 #define header(x) ((struct ext4_xattr_header *)(x))
 789
 790         if (i->value && i->value_len > sb->s_blocksize)
 791                 return -ENOSPC;
 792         if (s->base) {
 793                 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
 794                                         bs->bh->b_blocknr);
 795                 BUFFER_TRACE(bs->bh, "get_write_access");
 796                 error = ext4_journal_get_write_access(handle, bs->bh);
 797                 if (error)
 798                         goto cleanup;
 799                 lock_buffer(bs->bh);
 800
 801                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 802                         if (ce) {
 803                                 mb_cache_entry_free(ce);
 804                                 ce = NULL;
 805                         }
 806                         ea_bdebug(bs->bh, "modifying in-place");
 807                         error = ext4_xattr_set_entry(i, s);
 808                         if (!error) {
 809                                 if (!IS_LAST_ENTRY(s->first))
 810                                         ext4_xattr_rehash(header(s->base),
 811                                                           s->here);
 812                                 ext4_xattr_cache_insert(ext4_mb_cache,
 813                                         bs->bh);
 814                         }
 815                         unlock_buffer(bs->bh);
 816                         if (error == -EIO)
 817                                 goto bad_block;
 818                         if (!error)
 819                                 error = ext4_handle_dirty_xattr_block(handle,
 820                                                                       inode,
 821                                                                       bs->bh);
 822                         if (error)
 823                                 goto cleanup;
 824                         goto inserted;
 825                 } else {
 826                         int offset = (char *)s->here - bs->bh->b_data;
 827
 828                         unlock_buffer(bs->bh);
 829                         if (ce) {
 830                                 mb_cache_entry_release(ce);
 831                                 ce = NULL;
 832                         }
 833                         ea_bdebug(bs->bh, "cloning");
 834                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 835                         error = -ENOMEM;
 836                         if (s->base == NULL)
 837                                 goto cleanup;
 838                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 839                         s->first = ENTRY(header(s->base)+1);
 840                         header(s->base)->h_refcount = cpu_to_le32(1);
 841                         s->here = ENTRY(s->base + offset);
 842                         s->end = s->base + bs->bh->b_size;
 843                 }
 844         } else {
 845                 /* Allocate a buffer where we construct the new block. */
 846                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 847                 /* assert(header == s->base) */
 848                 error = -ENOMEM;
 849                 if (s->base == NULL)
 850                         goto cleanup;
 851                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 852                 header(s->base)->h_blocks = cpu_to_le32(1);
 853                 header(s->base)->h_refcount = cpu_to_le32(1);
 854                 s->first = ENTRY(header(s->base)+1);
 855                 s->here = ENTRY(header(s->base)+1);
 856                 s->end = s->base + sb->s_blocksize;
 857         }
 858
 859         error = ext4_xattr_set_entry(i, s);
 860         if (error == -EIO)
 861                 goto bad_block;
 862         if (error)
 863                 goto cleanup;
 864         if (!IS_LAST_ENTRY(s->first))
 865                 ext4_xattr_rehash(header(s->base), s->here);
 866
 867 inserted:
 868         if (!IS_LAST_ENTRY(s->first)) {
 869                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 870                 if (new_bh) {
 871                         /* We found an identical block in the cache. */
 872                         if (new_bh == bs->bh)
 873                                 ea_bdebug(new_bh, "keeping");
 874                         else {
 875                                 /* The old block is released after updating
 876                                    the inode. */
 877                                 error = dquot_alloc_block(inode,
 878                                                 EXT4_C2B(EXT4_SB(sb), 1));
 879                                 if (error)
 880                                         goto cleanup;
 881                                 BUFFER_TRACE(new_bh, "get_write_access");
 882                                 error = ext4_journal_get_write_access(handle,
 883                                                                       new_bh);
 884                                 if (error)
 885                                         goto cleanup_dquot;
 886                                 lock_buffer(new_bh);
 887                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 888                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 889                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 890                                 unlock_buffer(new_bh);
 891                                 error = ext4_handle_dirty_xattr_block(handle,
 892                                                                       inode,
 893                                                                       new_bh);
 894                                 if (error)
 895                                         goto cleanup_dquot;
 896                         }
 897                         mb_cache_entry_release(ce);
 898                         ce = NULL;
 899                 } else if (bs->bh && s->base == bs->bh->b_data) {
 900                         /* We were modifying this block in-place. */
 901                         ea_bdebug(bs->bh, "keeping this block");
 902                         new_bh = bs->bh;
 903                         get_bh(new_bh);
 904                 } else {
 905                         /* We need to allocate a new block */
 906                         ext4_fsblk_t goal, block;
 907
 908                         goal = ext4_group_first_block_no(sb,
 909                                                 EXT4_I(inode)->i_block_group);
 910
 911                         /* non-extent files can't have physical blocks past 2^32 */
 912                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 913                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 914
 915                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 916                                                      NULL, &error);
 917                         if (error)
 918                                 goto cleanup;
 919
 920                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 921                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 922
 923                         ea_idebug(inode, "creating block %llu",
 924                                   (unsigned long long)block);
 925
 926                         new_bh = sb_getblk(sb, block);
 927                         if (unlikely(!new_bh)) {
 928                                 error = -ENOMEM;
 929 getblk_failed:
 930                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 931                                                  EXT4_FREE_BLOCKS_METADATA);
 932                                 goto cleanup;
 933                         }
 934                         lock_buffer(new_bh);
 935                         error = ext4_journal_get_create_access(handle, new_bh);
 936                         if (error) {
 937                                 unlock_buffer(new_bh);
 938                                 error = -EIO;
 939                                 goto getblk_failed;
 940                         }
 941                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 942                         set_buffer_uptodate(new_bh);
 943                         unlock_buffer(new_bh);
 944                         ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
 945                         error = ext4_handle_dirty_xattr_block(handle,
 946                                                               inode, new_bh);
 947                         if (error)
 948                                 goto cleanup;
 949                 }
 950         }
 951
 952         /* Update the inode. */
 953         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 954
 955         /* Drop the previous xattr block. */
 956         if (bs->bh && bs->bh != new_bh)
 957                 ext4_xattr_release_block(handle, inode, bs->bh);
 958         error = 0;
 959
 960 cleanup:
 961         if (ce)
 962                 mb_cache_entry_release(ce);
 963         brelse(new_bh);
 964         if (!(bs->bh && s->base == bs->bh->b_data))
 965                 kfree(s->base);
 966
 967         return error;
 968
 969 cleanup_dquot:
 970         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 971         goto cleanup;
 972
 973 bad_block:
 974         EXT4_ERROR_INODE(inode, "bad block %llu",
 975                          EXT4_I(inode)->i_file_acl);
 976         goto cleanup;
 977
 978 #undef header
 979 }
 980
 981 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 982                           struct ext4_xattr_ibody_find *is)
 983 {
 984         struct ext4_xattr_ibody_header *header;
 985         struct ext4_inode *raw_inode;
 986         int error;
 987
 988         if (EXT4_I(inode)->i_extra_isize == 0)
 989                 return 0;
 990         raw_inode = ext4_raw_inode(&is->iloc);
 991         header = IHDR(inode, raw_inode);
 992         is->s.base = is->s.first = IFIRST(header);
 993         is->s.here = is->s.first;
 994         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 995         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 996                 error = ext4_xattr_check_names(IFIRST(header), is->s.end,
 997                                                IFIRST(header));
 998                 if (error)
 999                         return error;
1000                 /* Find the named attribute. */
1001                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1002                                               i->name, is->s.end -
1003                                               (void *)is->s.base, 0);
1004                 if (error && error != -ENODATA)
1005                         return error;
1006                 is->s.not_found = error;
1007         }
1008         return 0;
1009 }
1010
1011 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1012                                 struct ext4_xattr_info *i,
1013                                 struct ext4_xattr_ibody_find *is)
1014 {
1015         struct ext4_xattr_ibody_header *header;
1016         struct ext4_xattr_search *s = &is->s;
1017         int error;
1018
1019         if (EXT4_I(inode)->i_extra_isize == 0)
1020                 return -ENOSPC;
1021         error = ext4_xattr_set_entry(i, s);
1022         if (error) {
1023                 if (error == -ENOSPC &&
1024                     ext4_has_inline_data(inode)) {
1025                         error = ext4_try_to_evict_inline_data(handle, inode,
1026                                         EXT4_XATTR_LEN(strlen(i->name) +
1027                                         EXT4_XATTR_SIZE(i->value_len)));
1028                         if (error)
1029                                 return error;
1030                         error = ext4_xattr_ibody_find(inode, i, is);
1031                         if (error)
1032                                 return error;
1033                         error = ext4_xattr_set_entry(i, s);
1034                 }
1035                 if (error)
1036                         return error;
1037         }
1038         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1039         if (!IS_LAST_ENTRY(s->first)) {
1040                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1041                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1042         } else {
1043                 header->h_magic = cpu_to_le32(0);
1044                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1045         }
1046         return 0;
1047 }
1048
1049 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1050                                 struct ext4_xattr_info *i,
1051                                 struct ext4_xattr_ibody_find *is)
1052 {
1053         struct ext4_xattr_ibody_header *header;
1054         struct ext4_xattr_search *s = &is->s;
1055         int error;
1056
1057         if (EXT4_I(inode)->i_extra_isize == 0)
1058                 return -ENOSPC;
1059         error = ext4_xattr_set_entry(i, s);
1060         if (error)
1061                 return error;
1062         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1063         if (!IS_LAST_ENTRY(s->first)) {
1064                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1065                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1066         } else {
1067                 header->h_magic = cpu_to_le32(0);
1068                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1069         }
1070         return 0;
1071 }
1072
1073 /*
1074  * ext4_xattr_set_handle()
1075  *
1076  * Create, replace or remove an extended attribute for this inode.  Value
1077  * is NULL to remove an existing extended attribute, and non-NULL to
1078  * either replace an existing extended attribute, or create a new extended
1079  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1080  * specify that an extended attribute must exist and must not exist
1081  * previous to the call, respectively.
1082  *
1083  * Returns 0, or a negative error number on failure.
1084  */
1085 int
1086 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1087                       const char *name, const void *value, size_t value_len,
1088                       int flags)
1089 {
1090         struct ext4_xattr_info i = {
1091                 .name_index = name_index,
1092                 .name = name,
1093                 .value = value,
1094                 .value_len = value_len,
1095
1096         };
1097         struct ext4_xattr_ibody_find is = {
1098                 .s = { .not_found = -ENODATA, },
1099         };
1100         struct ext4_xattr_block_find bs = {
1101                 .s = { .not_found = -ENODATA, },
1102         };
1103         unsigned long no_expand;
1104         int error;
1105
1106         if (!name)
1107                 return -EINVAL;
1108         if (strlen(name) > 255)
1109                 return -ERANGE;
1110         down_write(&EXT4_I(inode)->xattr_sem);
1111         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1112         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1113
1114         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1115         if (error)
1116                 goto cleanup;
1117
1118         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1119                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1120                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1121                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1122         }
1123
1124         error = ext4_xattr_ibody_find(inode, &i, &is);
1125         if (error)
1126                 goto cleanup;
1127         if (is.s.not_found)
1128                 error = ext4_xattr_block_find(inode, &i, &bs);
1129         if (error)
1130                 goto cleanup;
1131         if (is.s.not_found && bs.s.not_found) {
1132                 error = -ENODATA;
1133                 if (flags & XATTR_REPLACE)
1134                         goto cleanup;
1135                 error = 0;
1136                 if (!value)
1137                         goto cleanup;
1138         } else {
1139                 error = -EEXIST;
1140                 if (flags & XATTR_CREATE)
1141                         goto cleanup;
1142         }
1143         if (!value) {
1144                 if (!is.s.not_found)
1145                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1146                 else if (!bs.s.not_found)
1147                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1148         } else {
1149                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1150                 if (!error && !bs.s.not_found) {
1151                         i.value = NULL;
1152                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1153                 } else if (error == -ENOSPC) {
1154                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1155                                 error = ext4_xattr_block_find(inode, &i, &bs);
1156                                 if (error)
1157                                         goto cleanup;
1158                         }
1159                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1160                         if (error)
1161                                 goto cleanup;
1162                         if (!is.s.not_found) {
1163                                 i.value = NULL;
1164                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1165                                                              &is);
1166                         }
1167                 }
1168         }
1169         if (!error) {
1170                 ext4_xattr_update_super_block(handle, inode->i_sb);
1171                 inode->i_ctime = ext4_current_time(inode);
1172                 if (!value)
1173                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1174                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1175                 /*
1176                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1177                  * error != 0.
1178                  */
1179                 is.iloc.bh = NULL;
1180                 if (IS_SYNC(inode))
1181                         ext4_handle_sync(handle);
1182         }
1183
1184 cleanup:
1185         brelse(is.iloc.bh);
1186         brelse(bs.bh);
1187         if (no_expand == 0)
1188                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1189         up_write(&EXT4_I(inode)->xattr_sem);
1190         return error;
1191 }
1192
1193 /*
1194  * ext4_xattr_set()
1195  *
1196  * Like ext4_xattr_set_handle, but start from an inode. This extended
1197  * attribute modification is a filesystem transaction by itself.
1198  *
1199  * Returns 0, or a negative error number on failure.
1200  */
1201 int
1202 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1203                const void *value, size_t value_len, int flags)
1204 {
1205         handle_t *handle;
1206         int error, retries = 0;
1207         int credits = ext4_jbd2_credits_xattr(inode);
1208
1209 retry:
1210         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1211         if (IS_ERR(handle)) {
1212                 error = PTR_ERR(handle);
1213         } else {
1214                 int error2;
1215
1216                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1217                                               value, value_len, flags);
1218                 error2 = ext4_journal_stop(handle);
1219                 if (error == -ENOSPC &&
1220                     ext4_should_retry_alloc(inode->i_sb, &retries))
1221                         goto retry;
1222                 if (error == 0)
1223                         error = error2;
1224         }
1225
1226         return error;
1227 }
1228
1229 /*
1230  * Shift the EA entries in the inode to create space for the increased
1231  * i_extra_isize.
1232  */
1233 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1234                                      int value_offs_shift, void *to,
1235                                      void *from, size_t n, int blocksize)
1236 {
1237         struct ext4_xattr_entry *last = entry;
1238         int new_offs;
1239
1240         /* Adjust the value offsets of the entries */
1241         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1242                 if (!last->e_value_block && last->e_value_size) {
1243                         new_offs = le16_to_cpu(last->e_value_offs) +
1244                                                         value_offs_shift;
1245                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1246                                  > blocksize);
1247                         last->e_value_offs = cpu_to_le16(new_offs);
1248                 }
1249         }
1250         /* Shift the entries by n bytes */
1251         memmove(to, from, n);
1252 }
1253
1254 /*
1255  * Expand an inode by new_extra_isize bytes when EAs are present.
1256  * Returns 0 on success or negative error number on failure.
1257  */
1258 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1259                                struct ext4_inode *raw_inode, handle_t *handle)
1260 {
1261         struct ext4_xattr_ibody_header *header;
1262         struct ext4_xattr_entry *entry, *last, *first;
1263         struct buffer_head *bh = NULL;
1264         struct ext4_xattr_ibody_find *is = NULL;
1265         struct ext4_xattr_block_find *bs = NULL;
1266         char *buffer = NULL, *b_entry_name = NULL;
1267         size_t min_offs, free;
1268         int total_ino;
1269         void *base, *start, *end;
1270         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1271         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1272
1273         down_write(&EXT4_I(inode)->xattr_sem);
1274 retry:
1275         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1276                 up_write(&EXT4_I(inode)->xattr_sem);
1277                 return 0;
1278         }
1279
1280         header = IHDR(inode, raw_inode);
1281         entry = IFIRST(header);
1282
1283         /*
1284          * Check if enough free space is available in the inode to shift the
1285          * entries ahead by new_extra_isize.
1286          */
1287
1288         base = start = entry;
1289         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1290         min_offs = end - base;
1291         last = entry;
1292         total_ino = sizeof(struct ext4_xattr_ibody_header);
1293
1294         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1295         if (free >= new_extra_isize) {
1296                 entry = IFIRST(header);
1297                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1298                                 - new_extra_isize, (void *)raw_inode +
1299                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1300                                 (void *)header, total_ino,
1301                                 inode->i_sb->s_blocksize);
1302                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1303                 error = 0;
1304                 goto cleanup;
1305         }
1306
1307         /*
1308          * Enough free space isn't available in the inode, check if
1309          * EA block can hold new_extra_isize bytes.
1310          */
1311         if (EXT4_I(inode)->i_file_acl) {
1312                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1313                 error = -EIO;
1314                 if (!bh)
1315                         goto cleanup;
1316                 if (ext4_xattr_check_block(inode, bh)) {
1317                         EXT4_ERROR_INODE(inode, "bad block %llu",
1318                                          EXT4_I(inode)->i_file_acl);
1319                         error = -EIO;
1320                         goto cleanup;
1321                 }
1322                 base = BHDR(bh);
1323                 first = BFIRST(bh);
1324                 end = bh->b_data + bh->b_size;
1325                 min_offs = end - base;
1326                 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1327                 if (free < new_extra_isize) {
1328                         if (!tried_min_extra_isize && s_min_extra_isize) {
1329                                 tried_min_extra_isize++;
1330                                 new_extra_isize = s_min_extra_isize;
1331                                 brelse(bh);
1332                                 goto retry;
1333                         }
1334                         error = -1;
1335                         goto cleanup;
1336                 }
1337         } else {
1338                 free = inode->i_sb->s_blocksize;
1339         }
1340
1341         while (new_extra_isize > 0) {
1342                 size_t offs, size, entry_size;
1343                 struct ext4_xattr_entry *small_entry = NULL;
1344                 struct ext4_xattr_info i = {
1345                         .value = NULL,
1346                         .value_len = 0,
1347                 };
1348                 unsigned int total_size;  /* EA entry size + value size */
1349                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1350                 unsigned int min_total_size = ~0U;
1351
1352                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1353                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1354                 if (!is || !bs) {
1355                         error = -ENOMEM;
1356                         goto cleanup;
1357                 }
1358
1359                 is->s.not_found = -ENODATA;
1360                 bs->s.not_found = -ENODATA;
1361                 is->iloc.bh = NULL;
1362                 bs->bh = NULL;
1363
1364                 last = IFIRST(header);
1365                 /* Find the entry best suited to be pushed into EA block */
1366                 entry = NULL;
1367                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1368                         total_size =
1369                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1370                                         EXT4_XATTR_LEN(last->e_name_len);
1371                         if (total_size <= free && total_size < min_total_size) {
1372                                 if (total_size < new_extra_isize) {
1373                                         small_entry = last;
1374                                 } else {
1375                                         entry = last;
1376                                         min_total_size = total_size;
1377                                 }
1378                         }
1379                 }
1380
1381                 if (entry == NULL) {
1382                         if (small_entry) {
1383                                 entry = small_entry;
1384                         } else {
1385                                 if (!tried_min_extra_isize &&
1386                                     s_min_extra_isize) {
1387                                         tried_min_extra_isize++;
1388                                         new_extra_isize = s_min_extra_isize;
1389                                         kfree(is); is = NULL;
1390                                         kfree(bs); bs = NULL;
1391                                         brelse(bh);
1392                                         goto retry;
1393                                 }
1394                                 error = -1;
1395                                 goto cleanup;
1396                         }
1397                 }
1398                 offs = le16_to_cpu(entry->e_value_offs);
1399                 size = le32_to_cpu(entry->e_value_size);
1400                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1401                 i.name_index = entry->e_name_index,
1402                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1403                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1404                 if (!buffer || !b_entry_name) {
1405                         error = -ENOMEM;
1406                         goto cleanup;
1407                 }
1408                 /* Save the entry name and the entry value */
1409                 memcpy(buffer, (void *)IFIRST(header) + offs,
1410                        EXT4_XATTR_SIZE(size));
1411                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1412                 b_entry_name[entry->e_name_len] = '\0';
1413                 i.name = b_entry_name;
1414
1415                 error = ext4_get_inode_loc(inode, &is->iloc);
1416                 if (error)
1417                         goto cleanup;
1418
1419                 error = ext4_xattr_ibody_find(inode, &i, is);
1420                 if (error)
1421                         goto cleanup;
1422
1423                 /* Remove the chosen entry from the inode */
1424                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1425                 if (error)
1426                         goto cleanup;
1427
1428                 entry = IFIRST(header);
1429                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1430                         shift_bytes = new_extra_isize;
1431                 else
1432                         shift_bytes = entry_size + size;
1433                 /* Adjust the offsets and shift the remaining entries ahead */
1434                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1435                         shift_bytes, (void *)raw_inode +
1436                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1437                         (void *)header, total_ino - entry_size,
1438                         inode->i_sb->s_blocksize);
1439
1440                 extra_isize += shift_bytes;
1441                 new_extra_isize -= shift_bytes;
1442                 EXT4_I(inode)->i_extra_isize = extra_isize;
1443
1444                 i.name = b_entry_name;
1445                 i.value = buffer;
1446                 i.value_len = size;
1447                 error = ext4_xattr_block_find(inode, &i, bs);
1448                 if (error)
1449                         goto cleanup;
1450
1451                 /* Add entry which was removed from the inode into the block */
1452                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1453                 if (error)
1454                         goto cleanup;
1455                 kfree(b_entry_name);
1456                 kfree(buffer);
1457                 b_entry_name = NULL;
1458                 buffer = NULL;
1459                 brelse(is->iloc.bh);
1460                 kfree(is);
1461                 kfree(bs);
1462         }
1463         brelse(bh);
1464         up_write(&EXT4_I(inode)->xattr_sem);
1465         return 0;
1466
1467 cleanup:
1468         kfree(b_entry_name);
1469         kfree(buffer);
1470         if (is)
1471                 brelse(is->iloc.bh);
1472         kfree(is);
1473         kfree(bs);
1474         brelse(bh);
1475         up_write(&EXT4_I(inode)->xattr_sem);
1476         return error;
1477 }
1478
1479
1480
1481 /*
1482  * ext4_xattr_delete_inode()
1483  *
1484  * Free extended attribute resources associated with this inode. This
1485  * is called immediately before an inode is freed. We have exclusive
1486  * access to the inode.
1487  */
1488 void
1489 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1490 {
1491         struct buffer_head *bh = NULL;
1492
1493         if (!EXT4_I(inode)->i_file_acl)
1494                 goto cleanup;
1495         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1496         if (!bh) {
1497                 EXT4_ERROR_INODE(inode, "block %llu read error",
1498                                  EXT4_I(inode)->i_file_acl);
1499                 goto cleanup;
1500         }
1501         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1502             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1503                 EXT4_ERROR_INODE(inode, "bad block %llu",
1504                                  EXT4_I(inode)->i_file_acl);
1505                 goto cleanup;
1506         }
1507         ext4_xattr_release_block(handle, inode, bh);
1508         EXT4_I(inode)->i_file_acl = 0;
1509
1510 cleanup:
1511         brelse(bh);
1512 }
1513
1514 /*
1515  * ext4_xattr_put_super()
1516  *
1517  * This is called when a file system is unmounted.
1518  */
1519 void
1520 ext4_xattr_put_super(struct super_block *sb)
1521 {
1522         mb_cache_shrink(sb->s_bdev);
1523 }
1524
1525 /*
1526  * ext4_xattr_cache_insert()
1527  *
1528  * Create a new entry in the extended attribute cache, and insert
1529  * it unless such an entry is already in the cache.
1530  *
1531  * Returns 0, or a negative error number on failure.
1532  */
1533 static void
1534 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1535 {
1536         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1537         struct mb_cache_entry *ce;
1538         int error;
1539
1540         ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
1541         if (!ce) {
1542                 ea_bdebug(bh, "out of memory");
1543                 return;
1544         }
1545         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1546         if (error) {
1547                 mb_cache_entry_free(ce);
1548                 if (error == -EBUSY) {
1549                         ea_bdebug(bh, "already in cache");
1550                         error = 0;
1551                 }
1552         } else {
1553                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1554                 mb_cache_entry_release(ce);
1555         }
1556 }
1557
1558 /*
1559  * ext4_xattr_cmp()
1560  *
1561  * Compare two extended attribute blocks for equality.
1562  *
1563  * Returns 0 if the blocks are equal, 1 if they differ, and
1564  * a negative error number on errors.
1565  */
1566 static int
1567 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1568                struct ext4_xattr_header *header2)
1569 {
1570         struct ext4_xattr_entry *entry1, *entry2;
1571
1572         entry1 = ENTRY(header1+1);
1573         entry2 = ENTRY(header2+1);
1574         while (!IS_LAST_ENTRY(entry1)) {
1575                 if (IS_LAST_ENTRY(entry2))
1576                         return 1;
1577                 if (entry1->e_hash != entry2->e_hash ||
1578                     entry1->e_name_index != entry2->e_name_index ||
1579                     entry1->e_name_len != entry2->e_name_len ||
1580                     entry1->e_value_size != entry2->e_value_size ||
1581                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1582                         return 1;
1583                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1584                         return -EIO;
1585                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1586                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1587                            le32_to_cpu(entry1->e_value_size)))
1588                         return 1;
1589
1590                 entry1 = EXT4_XATTR_NEXT(entry1);
1591                 entry2 = EXT4_XATTR_NEXT(entry2);
1592         }
1593         if (!IS_LAST_ENTRY(entry2))
1594                 return 1;
1595         return 0;
1596 }
1597
1598 /*
1599  * ext4_xattr_cache_find()
1600  *
1601  * Find an identical extended attribute block.
1602  *
1603  * Returns a pointer to the block found, or NULL if such a block was
1604  * not found or an error occurred.
1605  */
1606 static struct buffer_head *
1607 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1608                       struct mb_cache_entry **pce)
1609 {
1610         __u32 hash = le32_to_cpu(header->h_hash);
1611         struct mb_cache_entry *ce;
1612         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1613
1614         if (!header->h_hash)
1615                 return NULL;  /* never share */
1616         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1617 again:
1618         ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
1619                                        hash);
1620         while (ce) {
1621                 struct buffer_head *bh;
1622
1623                 if (IS_ERR(ce)) {
1624                         if (PTR_ERR(ce) == -EAGAIN)
1625                                 goto again;
1626                         break;
1627                 }
1628                 bh = sb_bread(inode->i_sb, ce->e_block);
1629                 if (!bh) {
1630                         EXT4_ERROR_INODE(inode, "block %lu read error",
1631                                          (unsigned long) ce->e_block);
1632                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1633                                 EXT4_XATTR_REFCOUNT_MAX) {
1634                         ea_idebug(inode, "block %lu refcount %d>=%d",
1635                                   (unsigned long) ce->e_block,
1636                                   le32_to_cpu(BHDR(bh)->h_refcount),
1637                                           EXT4_XATTR_REFCOUNT_MAX);
1638                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1639                         *pce = ce;
1640                         return bh;
1641                 }
1642                 brelse(bh);
1643                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1644         }
1645         return NULL;
1646 }
1647
1648 #define NAME_HASH_SHIFT 5
1649 #define VALUE_HASH_SHIFT 16
1650
1651 /*
1652  * ext4_xattr_hash_entry()
1653  *
1654  * Compute the hash of an extended attribute.
1655  */
1656 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1657                                          struct ext4_xattr_entry *entry)
1658 {
1659         __u32 hash = 0;
1660         char *name = entry->e_name;
1661         int n;
1662
1663         for (n = 0; n < entry->e_name_len; n++) {
1664                 hash = (hash << NAME_HASH_SHIFT) ^
1665                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1666                        *name++;
1667         }
1668
1669         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1670                 __le32 *value = (__le32 *)((char *)header +
1671                         le16_to_cpu(entry->e_value_offs));
1672                 for (n = (le32_to_cpu(entry->e_value_size) +
1673                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1674                         hash = (hash << VALUE_HASH_SHIFT) ^
1675                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1676                                le32_to_cpu(*value++);
1677                 }
1678         }
1679         entry->e_hash = cpu_to_le32(hash);
1680 }
1681
1682 #undef NAME_HASH_SHIFT
1683 #undef VALUE_HASH_SHIFT
1684
1685 #define BLOCK_HASH_SHIFT 16
1686
1687 /*
1688  * ext4_xattr_rehash()
1689  *
1690  * Re-compute the extended attribute hash value after an entry has changed.
1691  */
1692 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1693                               struct ext4_xattr_entry *entry)
1694 {
1695         struct ext4_xattr_entry *here;
1696         __u32 hash = 0;
1697
1698         ext4_xattr_hash_entry(header, entry);
1699         here = ENTRY(header+1);
1700         while (!IS_LAST_ENTRY(here)) {
1701                 if (!here->e_hash) {
1702                         /* Block is not shared if an entry's hash value == 0 */
1703                         hash = 0;
1704                         break;
1705                 }
1706                 hash = (hash << BLOCK_HASH_SHIFT) ^
1707                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1708                        le32_to_cpu(here->e_hash);
1709                 here = EXT4_XATTR_NEXT(here);
1710         }
1711         header->h_hash = cpu_to_le32(hash);
1712 }
1713
1714 #undef BLOCK_HASH_SHIFT
1715
1716 #define HASH_BUCKET_BITS        10
1717
1718 struct mb_cache *
1719 ext4_xattr_create_cache(char *name)
1720 {
1721         return mb_cache_create(name, HASH_BUCKET_BITS);
1722 }
1723
1724 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1725 {
1726         if (cache)
1727                 mb_cache_destroy(cache);
1728 }
1729