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_RO_COMPAT_FEATURE(inode->i_sb,
 146                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
 147             (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 148                 return 0;
 149         return 1;
 150 }
 151
 152 static void ext4_xattr_block_csum_set(struct inode *inode,
 153                                       sector_t block_nr,
 154                                       struct ext4_xattr_header *hdr)
 155 {
 156         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 157                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 158                 return;
 159
 160         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 161 }
 162
 163 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 164                                                 struct inode *inode,
 165                                                 struct buffer_head *bh)
 166 {
 167         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 168         return ext4_handle_dirty_metadata(handle, inode, bh);
 169 }
 170
 171 static inline const struct xattr_handler *
 172 ext4_xattr_handler(int name_index)
 173 {
 174         const struct xattr_handler *handler = NULL;
 175
 176         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 177                 handler = ext4_xattr_handler_map[name_index];
 178         return handler;
 179 }
 180
 181 /*
 182  * Inode operation listxattr()
 183  *
 184  * dentry->d_inode->i_mutex: don't care
 185  */
 186 ssize_t
 187 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 188 {
 189         return ext4_xattr_list(dentry, buffer, size);
 190 }
 191
 192 static int
 193 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 194 {
 195         while (!IS_LAST_ENTRY(entry)) {
 196                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
 197                 if ((void *)next >= end)
 198                         return -EIO;
 199                 entry = next;
 200         }
 201         return 0;
 202 }
 203
 204 static inline int
 205 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 206 {
 207         int error;
 208
 209         if (buffer_verified(bh))
 210                 return 0;
 211
 212         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 213             BHDR(bh)->h_blocks != cpu_to_le32(1))
 214                 return -EIO;
 215         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 216                 return -EIO;
 217         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 218         if (!error)
 219                 set_buffer_verified(bh);
 220         return error;
 221 }
 222
 223 static inline int
 224 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 225 {
 226         size_t value_size = le32_to_cpu(entry->e_value_size);
 227
 228         if (entry->e_value_block != 0 || value_size > size ||
 229             le16_to_cpu(entry->e_value_offs) + value_size > size)
 230                 return -EIO;
 231         return 0;
 232 }
 233
 234 static int
 235 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 236                       const char *name, size_t size, int sorted)
 237 {
 238         struct ext4_xattr_entry *entry;
 239         size_t name_len;
 240         int cmp = 1;
 241
 242         if (name == NULL)
 243                 return -EINVAL;
 244         name_len = strlen(name);
 245         entry = *pentry;
 246         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 247                 cmp = name_index - entry->e_name_index;
 248                 if (!cmp)
 249                         cmp = name_len - entry->e_name_len;
 250                 if (!cmp)
 251                         cmp = memcmp(name, entry->e_name, name_len);
 252                 if (cmp <= 0 && (sorted || cmp == 0))
 253                         break;
 254         }
 255         *pentry = entry;
 256         if (!cmp && ext4_xattr_check_entry(entry, size))
 257                         return -EIO;
 258         return cmp ? -ENODATA : 0;
 259 }
 260
 261 static int
 262 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 263                      void *buffer, size_t buffer_size)
 264 {
 265         struct buffer_head *bh = NULL;
 266         struct ext4_xattr_entry *entry;
 267         size_t size;
 268         int error;
 269         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 270
 271         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 272                   name_index, name, buffer, (long)buffer_size);
 273
 274         error = -ENODATA;
 275         if (!EXT4_I(inode)->i_file_acl)
 276                 goto cleanup;
 277         ea_idebug(inode, "reading block %llu",
 278                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 279         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 280         if (!bh)
 281                 goto cleanup;
 282         ea_bdebug(bh, "b_count=%d, refcount=%d",
 283                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 284         if (ext4_xattr_check_block(inode, bh)) {
 285 bad_block:
 286                 EXT4_ERROR_INODE(inode, "bad block %llu",
 287                                  EXT4_I(inode)->i_file_acl);
 288                 error = -EIO;
 289                 goto cleanup;
 290         }
 291         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 292         entry = BFIRST(bh);
 293         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 294         if (error == -EIO)
 295                 goto bad_block;
 296         if (error)
 297                 goto cleanup;
 298         size = le32_to_cpu(entry->e_value_size);
 299         if (buffer) {
 300                 error = -ERANGE;
 301                 if (size > buffer_size)
 302                         goto cleanup;
 303                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 304                        size);
 305         }
 306         error = size;
 307
 308 cleanup:
 309         brelse(bh);
 310         return error;
 311 }
 312
 313 int
 314 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 315                      void *buffer, size_t buffer_size)
 316 {
 317         struct ext4_xattr_ibody_header *header;
 318         struct ext4_xattr_entry *entry;
 319         struct ext4_inode *raw_inode;
 320         struct ext4_iloc iloc;
 321         size_t size;
 322         void *end;
 323         int error;
 324
 325         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 326                 return -ENODATA;
 327         error = ext4_get_inode_loc(inode, &iloc);
 328         if (error)
 329                 return error;
 330         raw_inode = ext4_raw_inode(&iloc);
 331         header = IHDR(inode, raw_inode);
 332         entry = IFIRST(header);
 333         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 334         error = ext4_xattr_check_names(entry, end);
 335         if (error)
 336                 goto cleanup;
 337         error = ext4_xattr_find_entry(&entry, name_index, name,
 338                                       end - (void *)entry, 0);
 339         if (error)
 340                 goto cleanup;
 341         size = le32_to_cpu(entry->e_value_size);
 342         if (buffer) {
 343                 error = -ERANGE;
 344                 if (size > buffer_size)
 345                         goto cleanup;
 346                 memcpy(buffer, (void *)IFIRST(header) +
 347                        le16_to_cpu(entry->e_value_offs), size);
 348         }
 349         error = size;
 350
 351 cleanup:
 352         brelse(iloc.bh);
 353         return error;
 354 }
 355
 356 /*
 357  * ext4_xattr_get()
 358  *
 359  * Copy an extended attribute into the buffer
 360  * provided, or compute the buffer size required.
 361  * Buffer is NULL to compute the size of the buffer required.
 362  *
 363  * Returns a negative error number on failure, or the number of bytes
 364  * used / required on success.
 365  */
 366 int
 367 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 368                void *buffer, size_t buffer_size)
 369 {
 370         int error;
 371
 372         down_read(&EXT4_I(inode)->xattr_sem);
 373         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 374                                      buffer_size);
 375         if (error == -ENODATA)
 376                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 377                                              buffer_size);
 378         up_read(&EXT4_I(inode)->xattr_sem);
 379         return error;
 380 }
 381
 382 static int
 383 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 384                         char *buffer, size_t buffer_size)
 385 {
 386         size_t rest = buffer_size;
 387
 388         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 389                 const struct xattr_handler *handler =
 390                         ext4_xattr_handler(entry->e_name_index);
 391
 392                 if (handler) {
 393                         size_t size = handler->list(dentry, buffer, rest,
 394                                                     entry->e_name,
 395                                                     entry->e_name_len,
 396                                                     handler->flags);
 397                         if (buffer) {
 398                                 if (size > rest)
 399                                         return -ERANGE;
 400                                 buffer += size;
 401                         }
 402                         rest -= size;
 403                 }
 404         }
 405         return buffer_size - rest;
 406 }
 407
 408 static int
 409 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 410 {
 411         struct inode *inode = dentry->d_inode;
 412         struct buffer_head *bh = NULL;
 413         int error;
 414         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 415
 416         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 417                   buffer, (long)buffer_size);
 418
 419         error = 0;
 420         if (!EXT4_I(inode)->i_file_acl)
 421                 goto cleanup;
 422         ea_idebug(inode, "reading block %llu",
 423                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 424         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 425         error = -EIO;
 426         if (!bh)
 427                 goto cleanup;
 428         ea_bdebug(bh, "b_count=%d, refcount=%d",
 429                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 430         if (ext4_xattr_check_block(inode, bh)) {
 431                 EXT4_ERROR_INODE(inode, "bad block %llu",
 432                                  EXT4_I(inode)->i_file_acl);
 433                 error = -EIO;
 434                 goto cleanup;
 435         }
 436         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 437         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 438
 439 cleanup:
 440         brelse(bh);
 441
 442         return error;
 443 }
 444
 445 static int
 446 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 447 {
 448         struct inode *inode = dentry->d_inode;
 449         struct ext4_xattr_ibody_header *header;
 450         struct ext4_inode *raw_inode;
 451         struct ext4_iloc iloc;
 452         void *end;
 453         int error;
 454
 455         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 456                 return 0;
 457         error = ext4_get_inode_loc(inode, &iloc);
 458         if (error)
 459                 return error;
 460         raw_inode = ext4_raw_inode(&iloc);
 461         header = IHDR(inode, raw_inode);
 462         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 463         error = ext4_xattr_check_names(IFIRST(header), end);
 464         if (error)
 465                 goto cleanup;
 466         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 467                                         buffer, buffer_size);
 468
 469 cleanup:
 470         brelse(iloc.bh);
 471         return error;
 472 }
 473
 474 /*
 475  * ext4_xattr_list()
 476  *
 477  * Copy a list of attribute names into the buffer
 478  * provided, or compute the buffer size required.
 479  * Buffer is NULL to compute the size of the buffer required.
 480  *
 481  * Returns a negative error number on failure, or the number of bytes
 482  * used / required on success.
 483  */
 484 static int
 485 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 486 {
 487         int ret, ret2;
 488
 489         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 490         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 491         if (ret < 0)
 492                 goto errout;
 493         if (buffer) {
 494                 buffer += ret;
 495                 buffer_size -= ret;
 496         }
 497         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 498         if (ret < 0)
 499                 goto errout;
 500         ret += ret2;
 501 errout:
 502         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 503         return ret;
 504 }
 505
 506 /*
 507  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 508  * not set, set it.
 509  */
 510 static void ext4_xattr_update_super_block(handle_t *handle,
 511                                           struct super_block *sb)
 512 {
 513         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 514                 return;
 515
 516         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 517                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 518                 ext4_handle_dirty_super(handle, sb);
 519         }
 520 }
 521
 522 /*
 523  * Release the xattr block BH: If the reference count is > 1, decrement
 524  * it; otherwise free the block.
 525  */
 526 static void
 527 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 528                          struct buffer_head *bh)
 529 {
 530         struct mb_cache_entry *ce = NULL;
 531         int error = 0;
 532         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 533
 534         ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
 535         error = ext4_journal_get_write_access(handle, bh);
 536         if (error)
 537                 goto out;
 538
 539         lock_buffer(bh);
 540         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 541                 ea_bdebug(bh, "refcount now=0; freeing");
 542                 if (ce)
 543                         mb_cache_entry_free(ce);
 544                 get_bh(bh);
 545                 ext4_free_blocks(handle, inode, bh, 0, 1,
 546                                  EXT4_FREE_BLOCKS_METADATA |
 547                                  EXT4_FREE_BLOCKS_FORGET);
 548                 unlock_buffer(bh);
 549         } else {
 550                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 551                 if (ce)
 552                         mb_cache_entry_release(ce);
 553                 unlock_buffer(bh);
 554                 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
 555                 if (IS_SYNC(inode))
 556                         ext4_handle_sync(handle);
 557                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 558                 ea_bdebug(bh, "refcount now=%d; releasing",
 559                           le32_to_cpu(BHDR(bh)->h_refcount));
 560         }
 561 out:
 562         ext4_std_error(inode->i_sb, error);
 563         return;
 564 }
 565
 566 /*
 567  * Find the available free space for EAs. This also returns the total number of
 568  * bytes used by EA entries.
 569  */
 570 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 571                                     size_t *min_offs, void *base, int *total)
 572 {
 573         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 574                 if (!last->e_value_block && last->e_value_size) {
 575                         size_t offs = le16_to_cpu(last->e_value_offs);
 576                         if (offs < *min_offs)
 577                                 *min_offs = offs;
 578                 }
 579                 if (total)
 580                         *total += EXT4_XATTR_LEN(last->e_name_len);
 581         }
 582         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 583 }
 584
 585 static int
 586 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 587 {
 588         struct ext4_xattr_entry *last;
 589         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 590
 591         /* Compute min_offs and last. */
 592         last = s->first;
 593         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 594                 if (!last->e_value_block && last->e_value_size) {
 595                         size_t offs = le16_to_cpu(last->e_value_offs);
 596                         if (offs < min_offs)
 597                                 min_offs = offs;
 598                 }
 599         }
 600         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 601         if (!s->not_found) {
 602                 if (!s->here->e_value_block && s->here->e_value_size) {
 603                         size_t size = le32_to_cpu(s->here->e_value_size);
 604                         free += EXT4_XATTR_SIZE(size);
 605                 }
 606                 free += EXT4_XATTR_LEN(name_len);
 607         }
 608         if (i->value) {
 609                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 610                     free < EXT4_XATTR_LEN(name_len) +
 611                            EXT4_XATTR_SIZE(i->value_len))
 612                         return -ENOSPC;
 613         }
 614
 615         if (i->value && s->not_found) {
 616                 /* Insert the new name. */
 617                 size_t size = EXT4_XATTR_LEN(name_len);
 618                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 619                 memmove((void *)s->here + size, s->here, rest);
 620                 memset(s->here, 0, size);
 621                 s->here->e_name_index = i->name_index;
 622                 s->here->e_name_len = name_len;
 623                 memcpy(s->here->e_name, i->name, name_len);
 624         } else {
 625                 if (!s->here->e_value_block && s->here->e_value_size) {
 626                         void *first_val = s->base + min_offs;
 627                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 628                         void *val = s->base + offs;
 629                         size_t size = EXT4_XATTR_SIZE(
 630                                 le32_to_cpu(s->here->e_value_size));
 631
 632                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 633                                 /* The old and the new value have the same
 634                                    size. Just replace. */
 635                                 s->here->e_value_size =
 636                                         cpu_to_le32(i->value_len);
 637                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 638                                         memset(val, 0, size);
 639                                 } else {
 640                                         /* Clear pad bytes first. */
 641                                         memset(val + size - EXT4_XATTR_PAD, 0,
 642                                                EXT4_XATTR_PAD);
 643                                         memcpy(val, i->value, i->value_len);
 644                                 }
 645                                 return 0;
 646                         }
 647
 648                         /* Remove the old value. */
 649                         memmove(first_val + size, first_val, val - first_val);
 650                         memset(first_val, 0, size);
 651                         s->here->e_value_size = 0;
 652                         s->here->e_value_offs = 0;
 653                         min_offs += size;
 654
 655                         /* Adjust all value offsets. */
 656                         last = s->first;
 657                         while (!IS_LAST_ENTRY(last)) {
 658                                 size_t o = le16_to_cpu(last->e_value_offs);
 659                                 if (!last->e_value_block &&
 660                                     last->e_value_size && o < offs)
 661                                         last->e_value_offs =
 662                                                 cpu_to_le16(o + size);
 663                                 last = EXT4_XATTR_NEXT(last);
 664                         }
 665                 }
 666                 if (!i->value) {
 667                         /* Remove the old name. */
 668                         size_t size = EXT4_XATTR_LEN(name_len);
 669                         last = ENTRY((void *)last - size);
 670                         memmove(s->here, (void *)s->here + size,
 671                                 (void *)last - (void *)s->here + sizeof(__u32));
 672                         memset(last, 0, size);
 673                 }
 674         }
 675
 676         if (i->value) {
 677                 /* Insert the new value. */
 678                 s->here->e_value_size = cpu_to_le32(i->value_len);
 679                 if (i->value_len) {
 680                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 681                         void *val = s->base + min_offs - size;
 682                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 683                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 684                                 memset(val, 0, size);
 685                         } else {
 686                                 /* Clear the pad bytes first. */
 687                                 memset(val + size - EXT4_XATTR_PAD, 0,
 688                                        EXT4_XATTR_PAD);
 689                                 memcpy(val, i->value, i->value_len);
 690                         }
 691                 }
 692         }
 693         return 0;
 694 }
 695
 696 struct ext4_xattr_block_find {
 697         struct ext4_xattr_search s;
 698         struct buffer_head *bh;
 699 };
 700
 701 static int
 702 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 703                       struct ext4_xattr_block_find *bs)
 704 {
 705         struct super_block *sb = inode->i_sb;
 706         int error;
 707
 708         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 709                   i->name_index, i->name, i->value, (long)i->value_len);
 710
 711         if (EXT4_I(inode)->i_file_acl) {
 712                 /* The inode already has an extended attribute block. */
 713                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 714                 error = -EIO;
 715                 if (!bs->bh)
 716                         goto cleanup;
 717                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 718                         atomic_read(&(bs->bh->b_count)),
 719                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 720                 if (ext4_xattr_check_block(inode, bs->bh)) {
 721                         EXT4_ERROR_INODE(inode, "bad block %llu",
 722                                          EXT4_I(inode)->i_file_acl);
 723                         error = -EIO;
 724                         goto cleanup;
 725                 }
 726                 /* Find the named attribute. */
 727                 bs->s.base = BHDR(bs->bh);
 728                 bs->s.first = BFIRST(bs->bh);
 729                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 730                 bs->s.here = bs->s.first;
 731                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 732                                               i->name, bs->bh->b_size, 1);
 733                 if (error && error != -ENODATA)
 734                         goto cleanup;
 735                 bs->s.not_found = error;
 736         }
 737         error = 0;
 738
 739 cleanup:
 740         return error;
 741 }
 742
 743 static int
 744 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 745                      struct ext4_xattr_info *i,
 746                      struct ext4_xattr_block_find *bs)
 747 {
 748         struct super_block *sb = inode->i_sb;
 749         struct buffer_head *new_bh = NULL;
 750         struct ext4_xattr_search *s = &bs->s;
 751         struct mb_cache_entry *ce = NULL;
 752         int error = 0;
 753         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 754
 755 #define header(x) ((struct ext4_xattr_header *)(x))
 756
 757         if (i->value && i->value_len > sb->s_blocksize)
 758                 return -ENOSPC;
 759         if (s->base) {
 760                 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
 761                                         bs->bh->b_blocknr);
 762                 error = ext4_journal_get_write_access(handle, bs->bh);
 763                 if (error)
 764                         goto cleanup;
 765                 lock_buffer(bs->bh);
 766
 767                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 768                         if (ce) {
 769                                 mb_cache_entry_free(ce);
 770                                 ce = NULL;
 771                         }
 772                         ea_bdebug(bs->bh, "modifying in-place");
 773                         error = ext4_xattr_set_entry(i, s);
 774                         if (!error) {
 775                                 if (!IS_LAST_ENTRY(s->first))
 776                                         ext4_xattr_rehash(header(s->base),
 777                                                           s->here);
 778                                 ext4_xattr_cache_insert(ext4_mb_cache,
 779                                         bs->bh);
 780                         }
 781                         unlock_buffer(bs->bh);
 782                         if (error == -EIO)
 783                                 goto bad_block;
 784                         if (!error)
 785                                 error = ext4_handle_dirty_xattr_block(handle,
 786                                                                       inode,
 787                                                                       bs->bh);
 788                         if (error)
 789                                 goto cleanup;
 790                         goto inserted;
 791                 } else {
 792                         int offset = (char *)s->here - bs->bh->b_data;
 793
 794                         unlock_buffer(bs->bh);
 795                         if (ce) {
 796                                 mb_cache_entry_release(ce);
 797                                 ce = NULL;
 798                         }
 799                         ea_bdebug(bs->bh, "cloning");
 800                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 801                         error = -ENOMEM;
 802                         if (s->base == NULL)
 803                                 goto cleanup;
 804                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 805                         s->first = ENTRY(header(s->base)+1);
 806                         header(s->base)->h_refcount = cpu_to_le32(1);
 807                         s->here = ENTRY(s->base + offset);
 808                         s->end = s->base + bs->bh->b_size;
 809                 }
 810         } else {
 811                 /* Allocate a buffer where we construct the new block. */
 812                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 813                 /* assert(header == s->base) */
 814                 error = -ENOMEM;
 815                 if (s->base == NULL)
 816                         goto cleanup;
 817                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 818                 header(s->base)->h_blocks = cpu_to_le32(1);
 819                 header(s->base)->h_refcount = cpu_to_le32(1);
 820                 s->first = ENTRY(header(s->base)+1);
 821                 s->here = ENTRY(header(s->base)+1);
 822                 s->end = s->base + sb->s_blocksize;
 823         }
 824
 825         error = ext4_xattr_set_entry(i, s);
 826         if (error == -EIO)
 827                 goto bad_block;
 828         if (error)
 829                 goto cleanup;
 830         if (!IS_LAST_ENTRY(s->first))
 831                 ext4_xattr_rehash(header(s->base), s->here);
 832
 833 inserted:
 834         if (!IS_LAST_ENTRY(s->first)) {
 835                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 836                 if (new_bh) {
 837                         /* We found an identical block in the cache. */
 838                         if (new_bh == bs->bh)
 839                                 ea_bdebug(new_bh, "keeping");
 840                         else {
 841                                 /* The old block is released after updating
 842                                    the inode. */
 843                                 error = dquot_alloc_block(inode,
 844                                                 EXT4_C2B(EXT4_SB(sb), 1));
 845                                 if (error)
 846                                         goto cleanup;
 847                                 error = ext4_journal_get_write_access(handle,
 848                                                                       new_bh);
 849                                 if (error)
 850                                         goto cleanup_dquot;
 851                                 lock_buffer(new_bh);
 852                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 853                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 854                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 855                                 unlock_buffer(new_bh);
 856                                 error = ext4_handle_dirty_xattr_block(handle,
 857                                                                       inode,
 858                                                                       new_bh);
 859                                 if (error)
 860                                         goto cleanup_dquot;
 861                         }
 862                         mb_cache_entry_release(ce);
 863                         ce = NULL;
 864                 } else if (bs->bh && s->base == bs->bh->b_data) {
 865                         /* We were modifying this block in-place. */
 866                         ea_bdebug(bs->bh, "keeping this block");
 867                         new_bh = bs->bh;
 868                         get_bh(new_bh);
 869                 } else {
 870                         /* We need to allocate a new block */
 871                         ext4_fsblk_t goal, block;
 872
 873                         goal = ext4_group_first_block_no(sb,
 874                                                 EXT4_I(inode)->i_block_group);
 875
 876                         /* non-extent files can't have physical blocks past 2^32 */
 877                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 878                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 879
 880                         /*
 881                          * take i_data_sem because we will test
 882                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 883                          */
 884                         down_read((&EXT4_I(inode)->i_data_sem));
 885                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 886                                                      NULL, &error);
 887                         up_read((&EXT4_I(inode)->i_data_sem));
 888                         if (error)
 889                                 goto cleanup;
 890
 891                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 892                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 893
 894                         ea_idebug(inode, "creating block %llu",
 895                                   (unsigned long long)block);
 896
 897                         new_bh = sb_getblk(sb, block);
 898                         if (unlikely(!new_bh)) {
 899                                 error = -ENOMEM;
 900 getblk_failed:
 901                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 902                                                  EXT4_FREE_BLOCKS_METADATA);
 903                                 goto cleanup;
 904                         }
 905                         lock_buffer(new_bh);
 906                         error = ext4_journal_get_create_access(handle, new_bh);
 907                         if (error) {
 908                                 unlock_buffer(new_bh);
 909                                 error = -EIO;
 910                                 goto getblk_failed;
 911                         }
 912                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 913                         set_buffer_uptodate(new_bh);
 914                         unlock_buffer(new_bh);
 915                         ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
 916                         error = ext4_handle_dirty_xattr_block(handle,
 917                                                               inode, new_bh);
 918                         if (error)
 919                                 goto cleanup;
 920                 }
 921         }
 922
 923         /* Update the inode. */
 924         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 925
 926         /* Drop the previous xattr block. */
 927         if (bs->bh && bs->bh != new_bh)
 928                 ext4_xattr_release_block(handle, inode, bs->bh);
 929         error = 0;
 930
 931 cleanup:
 932         if (ce)
 933                 mb_cache_entry_release(ce);
 934         brelse(new_bh);
 935         if (!(bs->bh && s->base == bs->bh->b_data))
 936                 kfree(s->base);
 937
 938         return error;
 939
 940 cleanup_dquot:
 941         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 942         goto cleanup;
 943
 944 bad_block:
 945         EXT4_ERROR_INODE(inode, "bad block %llu",
 946                          EXT4_I(inode)->i_file_acl);
 947         goto cleanup;
 948
 949 #undef header
 950 }
 951
 952 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 953                           struct ext4_xattr_ibody_find *is)
 954 {
 955         struct ext4_xattr_ibody_header *header;
 956         struct ext4_inode *raw_inode;
 957         int error;
 958
 959         if (EXT4_I(inode)->i_extra_isize == 0)
 960                 return 0;
 961         raw_inode = ext4_raw_inode(&is->iloc);
 962         header = IHDR(inode, raw_inode);
 963         is->s.base = is->s.first = IFIRST(header);
 964         is->s.here = is->s.first;
 965         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 966         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 967                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 968                 if (error)
 969                         return error;
 970                 /* Find the named attribute. */
 971                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 972                                               i->name, is->s.end -
 973                                               (void *)is->s.base, 0);
 974                 if (error && error != -ENODATA)
 975                         return error;
 976                 is->s.not_found = error;
 977         }
 978         return 0;
 979 }
 980
 981 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 982                                 struct ext4_xattr_info *i,
 983                                 struct ext4_xattr_ibody_find *is)
 984 {
 985         struct ext4_xattr_ibody_header *header;
 986         struct ext4_xattr_search *s = &is->s;
 987         int error;
 988
 989         if (EXT4_I(inode)->i_extra_isize == 0)
 990                 return -ENOSPC;
 991         error = ext4_xattr_set_entry(i, s);
 992         if (error) {
 993                 if (error == -ENOSPC &&
 994                     ext4_has_inline_data(inode)) {
 995                         error = ext4_try_to_evict_inline_data(handle, inode,
 996                                         EXT4_XATTR_LEN(strlen(i->name) +
 997                                         EXT4_XATTR_SIZE(i->value_len)));
 998                         if (error)
 999                                 return error;
1000                         error = ext4_xattr_ibody_find(inode, i, is);
1001                         if (error)
1002                                 return error;
1003                         error = ext4_xattr_set_entry(i, s);
1004                 }
1005                 if (error)
1006                         return error;
1007         }
1008         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1009         if (!IS_LAST_ENTRY(s->first)) {
1010                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1011                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1012         } else {
1013                 header->h_magic = cpu_to_le32(0);
1014                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1015         }
1016         return 0;
1017 }
1018
1019 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1020                                 struct ext4_xattr_info *i,
1021                                 struct ext4_xattr_ibody_find *is)
1022 {
1023         struct ext4_xattr_ibody_header *header;
1024         struct ext4_xattr_search *s = &is->s;
1025         int error;
1026
1027         if (EXT4_I(inode)->i_extra_isize == 0)
1028                 return -ENOSPC;
1029         error = ext4_xattr_set_entry(i, s);
1030         if (error)
1031                 return error;
1032         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1033         if (!IS_LAST_ENTRY(s->first)) {
1034                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1035                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1036         } else {
1037                 header->h_magic = cpu_to_le32(0);
1038                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1039         }
1040         return 0;
1041 }
1042
1043 /*
1044  * ext4_xattr_set_handle()
1045  *
1046  * Create, replace or remove an extended attribute for this inode.  Value
1047  * is NULL to remove an existing extended attribute, and non-NULL to
1048  * either replace an existing extended attribute, or create a new extended
1049  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1050  * specify that an extended attribute must exist and must not exist
1051  * previous to the call, respectively.
1052  *
1053  * Returns 0, or a negative error number on failure.
1054  */
1055 int
1056 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1057                       const char *name, const void *value, size_t value_len,
1058                       int flags)
1059 {
1060         struct ext4_xattr_info i = {
1061                 .name_index = name_index,
1062                 .name = name,
1063                 .value = value,
1064                 .value_len = value_len,
1065
1066         };
1067         struct ext4_xattr_ibody_find is = {
1068                 .s = { .not_found = -ENODATA, },
1069         };
1070         struct ext4_xattr_block_find bs = {
1071                 .s = { .not_found = -ENODATA, },
1072         };
1073         unsigned long no_expand;
1074         int error;
1075
1076         if (!name)
1077                 return -EINVAL;
1078         if (strlen(name) > 255)
1079                 return -ERANGE;
1080         down_write(&EXT4_I(inode)->xattr_sem);
1081         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1082         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1083
1084         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1085         if (error)
1086                 goto cleanup;
1087
1088         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1089                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1090                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1091                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1092         }
1093
1094         error = ext4_xattr_ibody_find(inode, &i, &is);
1095         if (error)
1096                 goto cleanup;
1097         if (is.s.not_found)
1098                 error = ext4_xattr_block_find(inode, &i, &bs);
1099         if (error)
1100                 goto cleanup;
1101         if (is.s.not_found && bs.s.not_found) {
1102                 error = -ENODATA;
1103                 if (flags & XATTR_REPLACE)
1104                         goto cleanup;
1105                 error = 0;
1106                 if (!value)
1107                         goto cleanup;
1108         } else {
1109                 error = -EEXIST;
1110                 if (flags & XATTR_CREATE)
1111                         goto cleanup;
1112         }
1113         if (!value) {
1114                 if (!is.s.not_found)
1115                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1116                 else if (!bs.s.not_found)
1117                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1118         } else {
1119                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1120                 if (!error && !bs.s.not_found) {
1121                         i.value = NULL;
1122                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1123                 } else if (error == -ENOSPC) {
1124                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1125                                 error = ext4_xattr_block_find(inode, &i, &bs);
1126                                 if (error)
1127                                         goto cleanup;
1128                         }
1129                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1130                         if (error)
1131                                 goto cleanup;
1132                         if (!is.s.not_found) {
1133                                 i.value = NULL;
1134                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1135                                                              &is);
1136                         }
1137                 }
1138         }
1139         if (!error) {
1140                 ext4_xattr_update_super_block(handle, inode->i_sb);
1141                 inode->i_ctime = ext4_current_time(inode);
1142                 if (!value)
1143                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1144                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1145                 /*
1146                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1147                  * error != 0.
1148                  */
1149                 is.iloc.bh = NULL;
1150                 if (IS_SYNC(inode))
1151                         ext4_handle_sync(handle);
1152         }
1153
1154 cleanup:
1155         brelse(is.iloc.bh);
1156         brelse(bs.bh);
1157         if (no_expand == 0)
1158                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1159         up_write(&EXT4_I(inode)->xattr_sem);
1160         return error;
1161 }
1162
1163 /*
1164  * ext4_xattr_set()
1165  *
1166  * Like ext4_xattr_set_handle, but start from an inode. This extended
1167  * attribute modification is a filesystem transaction by itself.
1168  *
1169  * Returns 0, or a negative error number on failure.
1170  */
1171 int
1172 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1173                const void *value, size_t value_len, int flags)
1174 {
1175         handle_t *handle;
1176         int error, retries = 0;
1177         int credits = ext4_jbd2_credits_xattr(inode);
1178
1179 retry:
1180         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1181         if (IS_ERR(handle)) {
1182                 error = PTR_ERR(handle);
1183         } else {
1184                 int error2;
1185
1186                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1187                                               value, value_len, flags);
1188                 error2 = ext4_journal_stop(handle);
1189                 if (error == -ENOSPC &&
1190                     ext4_should_retry_alloc(inode->i_sb, &retries))
1191                         goto retry;
1192                 if (error == 0)
1193                         error = error2;
1194         }
1195
1196         return error;
1197 }
1198
1199 /*
1200  * Shift the EA entries in the inode to create space for the increased
1201  * i_extra_isize.
1202  */
1203 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1204                                      int value_offs_shift, void *to,
1205                                      void *from, size_t n, int blocksize)
1206 {
1207         struct ext4_xattr_entry *last = entry;
1208         int new_offs;
1209
1210         /* Adjust the value offsets of the entries */
1211         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1212                 if (!last->e_value_block && last->e_value_size) {
1213                         new_offs = le16_to_cpu(last->e_value_offs) +
1214                                                         value_offs_shift;
1215                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1216                                  > blocksize);
1217                         last->e_value_offs = cpu_to_le16(new_offs);
1218                 }
1219         }
1220         /* Shift the entries by n bytes */
1221         memmove(to, from, n);
1222 }
1223
1224 /*
1225  * Expand an inode by new_extra_isize bytes when EAs are present.
1226  * Returns 0 on success or negative error number on failure.
1227  */
1228 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1229                                struct ext4_inode *raw_inode, handle_t *handle)
1230 {
1231         struct ext4_xattr_ibody_header *header;
1232         struct ext4_xattr_entry *entry, *last, *first;
1233         struct buffer_head *bh = NULL;
1234         struct ext4_xattr_ibody_find *is = NULL;
1235         struct ext4_xattr_block_find *bs = NULL;
1236         char *buffer = NULL, *b_entry_name = NULL;
1237         size_t min_offs, free;
1238         int total_ino;
1239         void *base, *start, *end;
1240         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1241         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1242
1243         down_write(&EXT4_I(inode)->xattr_sem);
1244 retry:
1245         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1246                 up_write(&EXT4_I(inode)->xattr_sem);
1247                 return 0;
1248         }
1249
1250         header = IHDR(inode, raw_inode);
1251         entry = IFIRST(header);
1252
1253         /*
1254          * Check if enough free space is available in the inode to shift the
1255          * entries ahead by new_extra_isize.
1256          */
1257
1258         base = start = entry;
1259         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1260         min_offs = end - base;
1261         last = entry;
1262         total_ino = sizeof(struct ext4_xattr_ibody_header);
1263
1264         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1265         if (free >= new_extra_isize) {
1266                 entry = IFIRST(header);
1267                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1268                                 - new_extra_isize, (void *)raw_inode +
1269                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1270                                 (void *)header, total_ino,
1271                                 inode->i_sb->s_blocksize);
1272                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1273                 error = 0;
1274                 goto cleanup;
1275         }
1276
1277         /*
1278          * Enough free space isn't available in the inode, check if
1279          * EA block can hold new_extra_isize bytes.
1280          */
1281         if (EXT4_I(inode)->i_file_acl) {
1282                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1283                 error = -EIO;
1284                 if (!bh)
1285                         goto cleanup;
1286                 if (ext4_xattr_check_block(inode, bh)) {
1287                         EXT4_ERROR_INODE(inode, "bad block %llu",
1288                                          EXT4_I(inode)->i_file_acl);
1289                         error = -EIO;
1290                         goto cleanup;
1291                 }
1292                 base = BHDR(bh);
1293                 first = BFIRST(bh);
1294                 end = bh->b_data + bh->b_size;
1295                 min_offs = end - base;
1296                 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1297                 if (free < new_extra_isize) {
1298                         if (!tried_min_extra_isize && s_min_extra_isize) {
1299                                 tried_min_extra_isize++;
1300                                 new_extra_isize = s_min_extra_isize;
1301                                 brelse(bh);
1302                                 goto retry;
1303                         }
1304                         error = -1;
1305                         goto cleanup;
1306                 }
1307         } else {
1308                 free = inode->i_sb->s_blocksize;
1309         }
1310
1311         while (new_extra_isize > 0) {
1312                 size_t offs, size, entry_size;
1313                 struct ext4_xattr_entry *small_entry = NULL;
1314                 struct ext4_xattr_info i = {
1315                         .value = NULL,
1316                         .value_len = 0,
1317                 };
1318                 unsigned int total_size;  /* EA entry size + value size */
1319                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1320                 unsigned int min_total_size = ~0U;
1321
1322                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1323                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1324                 if (!is || !bs) {
1325                         error = -ENOMEM;
1326                         goto cleanup;
1327                 }
1328
1329                 is->s.not_found = -ENODATA;
1330                 bs->s.not_found = -ENODATA;
1331                 is->iloc.bh = NULL;
1332                 bs->bh = NULL;
1333
1334                 last = IFIRST(header);
1335                 /* Find the entry best suited to be pushed into EA block */
1336                 entry = NULL;
1337                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1338                         total_size =
1339                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1340                                         EXT4_XATTR_LEN(last->e_name_len);
1341                         if (total_size <= free && total_size < min_total_size) {
1342                                 if (total_size < new_extra_isize) {
1343                                         small_entry = last;
1344                                 } else {
1345                                         entry = last;
1346                                         min_total_size = total_size;
1347                                 }
1348                         }
1349                 }
1350
1351                 if (entry == NULL) {
1352                         if (small_entry) {
1353                                 entry = small_entry;
1354                         } else {
1355                                 if (!tried_min_extra_isize &&
1356                                     s_min_extra_isize) {
1357                                         tried_min_extra_isize++;
1358                                         new_extra_isize = s_min_extra_isize;
1359                                         kfree(is); is = NULL;
1360                                         kfree(bs); bs = NULL;
1361                                         brelse(bh);
1362                                         goto retry;
1363                                 }
1364                                 error = -1;
1365                                 goto cleanup;
1366                         }
1367                 }
1368                 offs = le16_to_cpu(entry->e_value_offs);
1369                 size = le32_to_cpu(entry->e_value_size);
1370                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1371                 i.name_index = entry->e_name_index,
1372                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1373                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1374                 if (!buffer || !b_entry_name) {
1375                         error = -ENOMEM;
1376                         goto cleanup;
1377                 }
1378                 /* Save the entry name and the entry value */
1379                 memcpy(buffer, (void *)IFIRST(header) + offs,
1380                        EXT4_XATTR_SIZE(size));
1381                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1382                 b_entry_name[entry->e_name_len] = '\0';
1383                 i.name = b_entry_name;
1384
1385                 error = ext4_get_inode_loc(inode, &is->iloc);
1386                 if (error)
1387                         goto cleanup;
1388
1389                 error = ext4_xattr_ibody_find(inode, &i, is);
1390                 if (error)
1391                         goto cleanup;
1392
1393                 /* Remove the chosen entry from the inode */
1394                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1395                 if (error)
1396                         goto cleanup;
1397
1398                 entry = IFIRST(header);
1399                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1400                         shift_bytes = new_extra_isize;
1401                 else
1402                         shift_bytes = entry_size + size;
1403                 /* Adjust the offsets and shift the remaining entries ahead */
1404                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1405                         shift_bytes, (void *)raw_inode +
1406                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1407                         (void *)header, total_ino - entry_size,
1408                         inode->i_sb->s_blocksize);
1409
1410                 extra_isize += shift_bytes;
1411                 new_extra_isize -= shift_bytes;
1412                 EXT4_I(inode)->i_extra_isize = extra_isize;
1413
1414                 i.name = b_entry_name;
1415                 i.value = buffer;
1416                 i.value_len = size;
1417                 error = ext4_xattr_block_find(inode, &i, bs);
1418                 if (error)
1419                         goto cleanup;
1420
1421                 /* Add entry which was removed from the inode into the block */
1422                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1423                 if (error)
1424                         goto cleanup;
1425                 kfree(b_entry_name);
1426                 kfree(buffer);
1427                 b_entry_name = NULL;
1428                 buffer = NULL;
1429                 brelse(is->iloc.bh);
1430                 kfree(is);
1431                 kfree(bs);
1432         }
1433         brelse(bh);
1434         up_write(&EXT4_I(inode)->xattr_sem);
1435         return 0;
1436
1437 cleanup:
1438         kfree(b_entry_name);
1439         kfree(buffer);
1440         if (is)
1441                 brelse(is->iloc.bh);
1442         kfree(is);
1443         kfree(bs);
1444         brelse(bh);
1445         up_write(&EXT4_I(inode)->xattr_sem);
1446         return error;
1447 }
1448
1449
1450
1451 /*
1452  * ext4_xattr_delete_inode()
1453  *
1454  * Free extended attribute resources associated with this inode. This
1455  * is called immediately before an inode is freed. We have exclusive
1456  * access to the inode.
1457  */
1458 void
1459 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1460 {
1461         struct buffer_head *bh = NULL;
1462
1463         if (!EXT4_I(inode)->i_file_acl)
1464                 goto cleanup;
1465         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1466         if (!bh) {
1467                 EXT4_ERROR_INODE(inode, "block %llu read error",
1468                                  EXT4_I(inode)->i_file_acl);
1469                 goto cleanup;
1470         }
1471         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1472             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1473                 EXT4_ERROR_INODE(inode, "bad block %llu",
1474                                  EXT4_I(inode)->i_file_acl);
1475                 goto cleanup;
1476         }
1477         ext4_xattr_release_block(handle, inode, bh);
1478         EXT4_I(inode)->i_file_acl = 0;
1479
1480 cleanup:
1481         brelse(bh);
1482 }
1483
1484 /*
1485  * ext4_xattr_put_super()
1486  *
1487  * This is called when a file system is unmounted.
1488  */
1489 void
1490 ext4_xattr_put_super(struct super_block *sb)
1491 {
1492         mb_cache_shrink(sb->s_bdev);
1493 }
1494
1495 /*
1496  * ext4_xattr_cache_insert()
1497  *
1498  * Create a new entry in the extended attribute cache, and insert
1499  * it unless such an entry is already in the cache.
1500  *
1501  * Returns 0, or a negative error number on failure.
1502  */
1503 static void
1504 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1505 {
1506         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1507         struct mb_cache_entry *ce;
1508         int error;
1509
1510         ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
1511         if (!ce) {
1512                 ea_bdebug(bh, "out of memory");
1513                 return;
1514         }
1515         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1516         if (error) {
1517                 mb_cache_entry_free(ce);
1518                 if (error == -EBUSY) {
1519                         ea_bdebug(bh, "already in cache");
1520                         error = 0;
1521                 }
1522         } else {
1523                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1524                 mb_cache_entry_release(ce);
1525         }
1526 }
1527
1528 /*
1529  * ext4_xattr_cmp()
1530  *
1531  * Compare two extended attribute blocks for equality.
1532  *
1533  * Returns 0 if the blocks are equal, 1 if they differ, and
1534  * a negative error number on errors.
1535  */
1536 static int
1537 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1538                struct ext4_xattr_header *header2)
1539 {
1540         struct ext4_xattr_entry *entry1, *entry2;
1541
1542         entry1 = ENTRY(header1+1);
1543         entry2 = ENTRY(header2+1);
1544         while (!IS_LAST_ENTRY(entry1)) {
1545                 if (IS_LAST_ENTRY(entry2))
1546                         return 1;
1547                 if (entry1->e_hash != entry2->e_hash ||
1548                     entry1->e_name_index != entry2->e_name_index ||
1549                     entry1->e_name_len != entry2->e_name_len ||
1550                     entry1->e_value_size != entry2->e_value_size ||
1551                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1552                         return 1;
1553                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1554                         return -EIO;
1555                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1556                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1557                            le32_to_cpu(entry1->e_value_size)))
1558                         return 1;
1559
1560                 entry1 = EXT4_XATTR_NEXT(entry1);
1561                 entry2 = EXT4_XATTR_NEXT(entry2);
1562         }
1563         if (!IS_LAST_ENTRY(entry2))
1564                 return 1;
1565         return 0;
1566 }
1567
1568 /*
1569  * ext4_xattr_cache_find()
1570  *
1571  * Find an identical extended attribute block.
1572  *
1573  * Returns a pointer to the block found, or NULL if such a block was
1574  * not found or an error occurred.
1575  */
1576 static struct buffer_head *
1577 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1578                       struct mb_cache_entry **pce)
1579 {
1580         __u32 hash = le32_to_cpu(header->h_hash);
1581         struct mb_cache_entry *ce;
1582         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1583
1584         if (!header->h_hash)
1585                 return NULL;  /* never share */
1586         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1587 again:
1588         ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
1589                                        hash);
1590         while (ce) {
1591                 struct buffer_head *bh;
1592
1593                 if (IS_ERR(ce)) {
1594                         if (PTR_ERR(ce) == -EAGAIN)
1595                                 goto again;
1596                         break;
1597                 }
1598                 bh = sb_bread(inode->i_sb, ce->e_block);
1599                 if (!bh) {
1600                         EXT4_ERROR_INODE(inode, "block %lu read error",
1601                                          (unsigned long) ce->e_block);
1602                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1603                                 EXT4_XATTR_REFCOUNT_MAX) {
1604                         ea_idebug(inode, "block %lu refcount %d>=%d",
1605                                   (unsigned long) ce->e_block,
1606                                   le32_to_cpu(BHDR(bh)->h_refcount),
1607                                           EXT4_XATTR_REFCOUNT_MAX);
1608                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1609                         *pce = ce;
1610                         return bh;
1611                 }
1612                 brelse(bh);
1613                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1614         }
1615         return NULL;
1616 }
1617
1618 #define NAME_HASH_SHIFT 5
1619 #define VALUE_HASH_SHIFT 16
1620
1621 /*
1622  * ext4_xattr_hash_entry()
1623  *
1624  * Compute the hash of an extended attribute.
1625  */
1626 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1627                                          struct ext4_xattr_entry *entry)
1628 {
1629         __u32 hash = 0;
1630         char *name = entry->e_name;
1631         int n;
1632
1633         for (n = 0; n < entry->e_name_len; n++) {
1634                 hash = (hash << NAME_HASH_SHIFT) ^
1635                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1636                        *name++;
1637         }
1638
1639         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1640                 __le32 *value = (__le32 *)((char *)header +
1641                         le16_to_cpu(entry->e_value_offs));
1642                 for (n = (le32_to_cpu(entry->e_value_size) +
1643                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1644                         hash = (hash << VALUE_HASH_SHIFT) ^
1645                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1646                                le32_to_cpu(*value++);
1647                 }
1648         }
1649         entry->e_hash = cpu_to_le32(hash);
1650 }
1651
1652 #undef NAME_HASH_SHIFT
1653 #undef VALUE_HASH_SHIFT
1654
1655 #define BLOCK_HASH_SHIFT 16
1656
1657 /*
1658  * ext4_xattr_rehash()
1659  *
1660  * Re-compute the extended attribute hash value after an entry has changed.
1661  */
1662 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1663                               struct ext4_xattr_entry *entry)
1664 {
1665         struct ext4_xattr_entry *here;
1666         __u32 hash = 0;
1667
1668         ext4_xattr_hash_entry(header, entry);
1669         here = ENTRY(header+1);
1670         while (!IS_LAST_ENTRY(here)) {
1671                 if (!here->e_hash) {
1672                         /* Block is not shared if an entry's hash value == 0 */
1673                         hash = 0;
1674                         break;
1675                 }
1676                 hash = (hash << BLOCK_HASH_SHIFT) ^
1677                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1678                        le32_to_cpu(here->e_hash);
1679                 here = EXT4_XATTR_NEXT(here);
1680         }
1681         header->h_hash = cpu_to_le32(hash);
1682 }
1683
1684 #undef BLOCK_HASH_SHIFT
1685
1686 #define HASH_BUCKET_BITS        10
1687
1688 struct mb_cache *
1689 ext4_xattr_create_cache(char *name)
1690 {
1691         return mb_cache_create(name, HASH_BUCKET_BITS);
1692 }
1693
1694 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1695 {
1696         if (cache)
1697                 mb_cache_destroy(cache);
1698 }
1699