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 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 struct mb_cache *ext4_xattr_cache;
  94
  95 static const struct xattr_handler *ext4_xattr_handler_map[] = {
  96         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  97 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  98         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
  99         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
 100 #endif
 101         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 102 #ifdef CONFIG_EXT4_FS_SECURITY
 103         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 104 #endif
 105 };
 106
 107 const struct xattr_handler *ext4_xattr_handlers[] = {
 108         &ext4_xattr_user_handler,
 109         &ext4_xattr_trusted_handler,
 110 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 111         &ext4_xattr_acl_access_handler,
 112         &ext4_xattr_acl_default_handler,
 113 #endif
 114 #ifdef CONFIG_EXT4_FS_SECURITY
 115         &ext4_xattr_security_handler,
 116 #endif
 117         NULL
 118 };
 119
 120 static __le32 ext4_xattr_block_csum(struct inode *inode,
 121                                     sector_t block_nr,
 122                                     struct ext4_xattr_header *hdr)
 123 {
 124         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 125         __u32 csum;
 126         __le32 save_csum;
 127         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 128
 129         save_csum = hdr->h_checksum;
 130         hdr->h_checksum = 0;
 131         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 132                            sizeof(dsk_block_nr));
 133         csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
 134                            EXT4_BLOCK_SIZE(inode->i_sb));
 135
 136         hdr->h_checksum = save_csum;
 137         return cpu_to_le32(csum);
 138 }
 139
 140 static int ext4_xattr_block_csum_verify(struct inode *inode,
 141                                         sector_t block_nr,
 142                                         struct ext4_xattr_header *hdr)
 143 {
 144         if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 145                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
 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_RO_COMPAT_FEATURE(inode->i_sb,
 156                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 157                 return;
 158
 159         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 160 }
 161
 162 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 163                                                 struct inode *inode,
 164                                                 struct buffer_head *bh)
 165 {
 166         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 167         return ext4_handle_dirty_metadata(handle, inode, bh);
 168 }
 169
 170 static inline const struct xattr_handler *
 171 ext4_xattr_handler(int name_index)
 172 {
 173         const struct xattr_handler *handler = NULL;
 174
 175         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 176                 handler = ext4_xattr_handler_map[name_index];
 177         return handler;
 178 }
 179
 180 /*
 181  * Inode operation listxattr()
 182  *
 183  * dentry->d_inode->i_mutex: don't care
 184  */
 185 ssize_t
 186 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 187 {
 188         return ext4_xattr_list(dentry, buffer, size);
 189 }
 190
 191 static int
 192 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 193 {
 194         while (!IS_LAST_ENTRY(entry)) {
 195                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
 196                 if ((void *)next >= end)
 197                         return -EIO;
 198                 entry = next;
 199         }
 200         return 0;
 201 }
 202
 203 static inline int
 204 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 205 {
 206         int error;
 207
 208         if (buffer_verified(bh))
 209                 return 0;
 210
 211         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 212             BHDR(bh)->h_blocks != cpu_to_le32(1))
 213                 return -EIO;
 214         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 215                 return -EIO;
 216         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 217         if (!error)
 218                 set_buffer_verified(bh);
 219         return error;
 220 }
 221
 222 static inline int
 223 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 224 {
 225         size_t value_size = le32_to_cpu(entry->e_value_size);
 226
 227         if (entry->e_value_block != 0 || value_size > size ||
 228             le16_to_cpu(entry->e_value_offs) + value_size > size)
 229                 return -EIO;
 230         return 0;
 231 }
 232
 233 static int
 234 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 235                       const char *name, size_t size, int sorted)
 236 {
 237         struct ext4_xattr_entry *entry;
 238         size_t name_len;
 239         int cmp = 1;
 240
 241         if (name == NULL)
 242                 return -EINVAL;
 243         name_len = strlen(name);
 244         entry = *pentry;
 245         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 246                 cmp = name_index - entry->e_name_index;
 247                 if (!cmp)
 248                         cmp = name_len - entry->e_name_len;
 249                 if (!cmp)
 250                         cmp = memcmp(name, entry->e_name, name_len);
 251                 if (cmp <= 0 && (sorted || cmp == 0))
 252                         break;
 253         }
 254         *pentry = entry;
 255         if (!cmp && ext4_xattr_check_entry(entry, size))
 256                         return -EIO;
 257         return cmp ? -ENODATA : 0;
 258 }
 259
 260 static int
 261 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 262                      void *buffer, size_t buffer_size)
 263 {
 264         struct buffer_head *bh = NULL;
 265         struct ext4_xattr_entry *entry;
 266         size_t size;
 267         int error;
 268
 269         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 270                   name_index, name, buffer, (long)buffer_size);
 271
 272         error = -ENODATA;
 273         if (!EXT4_I(inode)->i_file_acl)
 274                 goto cleanup;
 275         ea_idebug(inode, "reading block %llu",
 276                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 277         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 278         if (!bh)
 279                 goto cleanup;
 280         ea_bdebug(bh, "b_count=%d, refcount=%d",
 281                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 282         if (ext4_xattr_check_block(inode, bh)) {
 283 bad_block:
 284                 EXT4_ERROR_INODE(inode, "bad block %llu",
 285                                  EXT4_I(inode)->i_file_acl);
 286                 error = -EIO;
 287                 goto cleanup;
 288         }
 289         ext4_xattr_cache_insert(bh);
 290         entry = BFIRST(bh);
 291         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 292         if (error == -EIO)
 293                 goto bad_block;
 294         if (error)
 295                 goto cleanup;
 296         size = le32_to_cpu(entry->e_value_size);
 297         if (buffer) {
 298                 error = -ERANGE;
 299                 if (size > buffer_size)
 300                         goto cleanup;
 301                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 302                        size);
 303         }
 304         error = size;
 305
 306 cleanup:
 307         brelse(bh);
 308         return error;
 309 }
 310
 311 int
 312 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 313                      void *buffer, size_t buffer_size)
 314 {
 315         struct ext4_xattr_ibody_header *header;
 316         struct ext4_xattr_entry *entry;
 317         struct ext4_inode *raw_inode;
 318         struct ext4_iloc iloc;
 319         size_t size;
 320         void *end;
 321         int error;
 322
 323         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 324                 return -ENODATA;
 325         error = ext4_get_inode_loc(inode, &iloc);
 326         if (error)
 327                 return error;
 328         raw_inode = ext4_raw_inode(&iloc);
 329         header = IHDR(inode, raw_inode);
 330         entry = IFIRST(header);
 331         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 332         error = ext4_xattr_check_names(entry, end);
 333         if (error)
 334                 goto cleanup;
 335         error = ext4_xattr_find_entry(&entry, name_index, name,
 336                                       end - (void *)entry, 0);
 337         if (error)
 338                 goto cleanup;
 339         size = le32_to_cpu(entry->e_value_size);
 340         if (buffer) {
 341                 error = -ERANGE;
 342                 if (size > buffer_size)
 343                         goto cleanup;
 344                 memcpy(buffer, (void *)IFIRST(header) +
 345                        le16_to_cpu(entry->e_value_offs), size);
 346         }
 347         error = size;
 348
 349 cleanup:
 350         brelse(iloc.bh);
 351         return error;
 352 }
 353
 354 /*
 355  * ext4_xattr_get()
 356  *
 357  * Copy an extended attribute into the buffer
 358  * provided, or compute the buffer size required.
 359  * Buffer is NULL to compute the size of the buffer required.
 360  *
 361  * Returns a negative error number on failure, or the number of bytes
 362  * used / required on success.
 363  */
 364 int
 365 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 366                void *buffer, size_t buffer_size)
 367 {
 368         int error;
 369
 370         down_read(&EXT4_I(inode)->xattr_sem);
 371         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 372                                      buffer_size);
 373         if (error == -ENODATA)
 374                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 375                                              buffer_size);
 376         up_read(&EXT4_I(inode)->xattr_sem);
 377         return error;
 378 }
 379
 380 static int
 381 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 382                         char *buffer, size_t buffer_size)
 383 {
 384         size_t rest = buffer_size;
 385
 386         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 387                 const struct xattr_handler *handler =
 388                         ext4_xattr_handler(entry->e_name_index);
 389
 390                 if (handler) {
 391                         size_t size = handler->list(dentry, buffer, rest,
 392                                                     entry->e_name,
 393                                                     entry->e_name_len,
 394                                                     handler->flags);
 395                         if (buffer) {
 396                                 if (size > rest)
 397                                         return -ERANGE;
 398                                 buffer += size;
 399                         }
 400                         rest -= size;
 401                 }
 402         }
 403         return buffer_size - rest;
 404 }
 405
 406 static int
 407 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 408 {
 409         struct inode *inode = dentry->d_inode;
 410         struct buffer_head *bh = NULL;
 411         int error;
 412
 413         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 414                   buffer, (long)buffer_size);
 415
 416         error = 0;
 417         if (!EXT4_I(inode)->i_file_acl)
 418                 goto cleanup;
 419         ea_idebug(inode, "reading block %llu",
 420                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 421         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 422         error = -EIO;
 423         if (!bh)
 424                 goto cleanup;
 425         ea_bdebug(bh, "b_count=%d, refcount=%d",
 426                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 427         if (ext4_xattr_check_block(inode, bh)) {
 428                 EXT4_ERROR_INODE(inode, "bad block %llu",
 429                                  EXT4_I(inode)->i_file_acl);
 430                 error = -EIO;
 431                 goto cleanup;
 432         }
 433         ext4_xattr_cache_insert(bh);
 434         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 435
 436 cleanup:
 437         brelse(bh);
 438
 439         return error;
 440 }
 441
 442 static int
 443 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 444 {
 445         struct inode *inode = dentry->d_inode;
 446         struct ext4_xattr_ibody_header *header;
 447         struct ext4_inode *raw_inode;
 448         struct ext4_iloc iloc;
 449         void *end;
 450         int error;
 451
 452         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 453                 return 0;
 454         error = ext4_get_inode_loc(inode, &iloc);
 455         if (error)
 456                 return error;
 457         raw_inode = ext4_raw_inode(&iloc);
 458         header = IHDR(inode, raw_inode);
 459         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 460         error = ext4_xattr_check_names(IFIRST(header), end);
 461         if (error)
 462                 goto cleanup;
 463         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 464                                         buffer, buffer_size);
 465
 466 cleanup:
 467         brelse(iloc.bh);
 468         return error;
 469 }
 470
 471 /*
 472  * ext4_xattr_list()
 473  *
 474  * Copy a list of attribute names into the buffer
 475  * provided, or compute the buffer size required.
 476  * Buffer is NULL to compute the size of the buffer required.
 477  *
 478  * Returns a negative error number on failure, or the number of bytes
 479  * used / required on success.
 480  */
 481 static int
 482 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 483 {
 484         int ret, ret2;
 485
 486         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 487         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 488         if (ret < 0)
 489                 goto errout;
 490         if (buffer) {
 491                 buffer += ret;
 492                 buffer_size -= ret;
 493         }
 494         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 495         if (ret < 0)
 496                 goto errout;
 497         ret += ret2;
 498 errout:
 499         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 500         return ret;
 501 }
 502
 503 /*
 504  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 505  * not set, set it.
 506  */
 507 static void ext4_xattr_update_super_block(handle_t *handle,
 508                                           struct super_block *sb)
 509 {
 510         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 511                 return;
 512
 513         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 514                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 515                 ext4_handle_dirty_super(handle, sb);
 516         }
 517 }
 518
 519 /*
 520  * Release the xattr block BH: If the reference count is > 1, decrement
 521  * it; otherwise free the block.
 522  */
 523 static void
 524 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 525                          struct buffer_head *bh)
 526 {
 527         struct mb_cache_entry *ce = NULL;
 528         int error = 0;
 529
 530         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 531         error = ext4_journal_get_write_access(handle, bh);
 532         if (error)
 533                 goto out;
 534
 535         lock_buffer(bh);
 536         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 537                 ea_bdebug(bh, "refcount now=0; freeing");
 538                 if (ce)
 539                         mb_cache_entry_free(ce);
 540                 get_bh(bh);
 541                 ext4_free_blocks(handle, inode, bh, 0, 1,
 542                                  EXT4_FREE_BLOCKS_METADATA |
 543                                  EXT4_FREE_BLOCKS_FORGET);
 544                 unlock_buffer(bh);
 545         } else {
 546                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 547                 if (ce)
 548                         mb_cache_entry_release(ce);
 549                 unlock_buffer(bh);
 550                 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
 551                 if (IS_SYNC(inode))
 552                         ext4_handle_sync(handle);
 553                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 554                 ea_bdebug(bh, "refcount now=%d; releasing",
 555                           le32_to_cpu(BHDR(bh)->h_refcount));
 556         }
 557 out:
 558         ext4_std_error(inode->i_sb, error);
 559         return;
 560 }
 561
 562 /*
 563  * Find the available free space for EAs. This also returns the total number of
 564  * bytes used by EA entries.
 565  */
 566 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 567                                     size_t *min_offs, void *base, int *total)
 568 {
 569         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 570                 *total += EXT4_XATTR_LEN(last->e_name_len);
 571                 if (!last->e_value_block && last->e_value_size) {
 572                         size_t offs = le16_to_cpu(last->e_value_offs);
 573                         if (offs < *min_offs)
 574                                 *min_offs = offs;
 575                 }
 576         }
 577         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 578 }
 579
 580 static int
 581 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 582 {
 583         struct ext4_xattr_entry *last;
 584         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 585
 586         /* Compute min_offs and last. */
 587         last = s->first;
 588         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 589                 if (!last->e_value_block && last->e_value_size) {
 590                         size_t offs = le16_to_cpu(last->e_value_offs);
 591                         if (offs < min_offs)
 592                                 min_offs = offs;
 593                 }
 594         }
 595         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 596         if (!s->not_found) {
 597                 if (!s->here->e_value_block && s->here->e_value_size) {
 598                         size_t size = le32_to_cpu(s->here->e_value_size);
 599                         free += EXT4_XATTR_SIZE(size);
 600                 }
 601                 free += EXT4_XATTR_LEN(name_len);
 602         }
 603         if (i->value) {
 604                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 605                     free < EXT4_XATTR_LEN(name_len) +
 606                            EXT4_XATTR_SIZE(i->value_len))
 607                         return -ENOSPC;
 608         }
 609
 610         if (i->value && s->not_found) {
 611                 /* Insert the new name. */
 612                 size_t size = EXT4_XATTR_LEN(name_len);
 613                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 614                 memmove((void *)s->here + size, s->here, rest);
 615                 memset(s->here, 0, size);
 616                 s->here->e_name_index = i->name_index;
 617                 s->here->e_name_len = name_len;
 618                 memcpy(s->here->e_name, i->name, name_len);
 619         } else {
 620                 if (!s->here->e_value_block && s->here->e_value_size) {
 621                         void *first_val = s->base + min_offs;
 622                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 623                         void *val = s->base + offs;
 624                         size_t size = EXT4_XATTR_SIZE(
 625                                 le32_to_cpu(s->here->e_value_size));
 626
 627                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 628                                 /* The old and the new value have the same
 629                                    size. Just replace. */
 630                                 s->here->e_value_size =
 631                                         cpu_to_le32(i->value_len);
 632                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 633                                         memset(val, 0, size);
 634                                 } else {
 635                                         /* Clear pad bytes first. */
 636                                         memset(val + size - EXT4_XATTR_PAD, 0,
 637                                                EXT4_XATTR_PAD);
 638                                         memcpy(val, i->value, i->value_len);
 639                                 }
 640                                 return 0;
 641                         }
 642
 643                         /* Remove the old value. */
 644                         memmove(first_val + size, first_val, val - first_val);
 645                         memset(first_val, 0, size);
 646                         s->here->e_value_size = 0;
 647                         s->here->e_value_offs = 0;
 648                         min_offs += size;
 649
 650                         /* Adjust all value offsets. */
 651                         last = s->first;
 652                         while (!IS_LAST_ENTRY(last)) {
 653                                 size_t o = le16_to_cpu(last->e_value_offs);
 654                                 if (!last->e_value_block &&
 655                                     last->e_value_size && o < offs)
 656                                         last->e_value_offs =
 657                                                 cpu_to_le16(o + size);
 658                                 last = EXT4_XATTR_NEXT(last);
 659                         }
 660                 }
 661                 if (!i->value) {
 662                         /* Remove the old name. */
 663                         size_t size = EXT4_XATTR_LEN(name_len);
 664                         last = ENTRY((void *)last - size);
 665                         memmove(s->here, (void *)s->here + size,
 666                                 (void *)last - (void *)s->here + sizeof(__u32));
 667                         memset(last, 0, size);
 668                 }
 669         }
 670
 671         if (i->value) {
 672                 /* Insert the new value. */
 673                 s->here->e_value_size = cpu_to_le32(i->value_len);
 674                 if (i->value_len) {
 675                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 676                         void *val = s->base + min_offs - size;
 677                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 678                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 679                                 memset(val, 0, size);
 680                         } else {
 681                                 /* Clear the pad bytes first. */
 682                                 memset(val + size - EXT4_XATTR_PAD, 0,
 683                                        EXT4_XATTR_PAD);
 684                                 memcpy(val, i->value, i->value_len);
 685                         }
 686                 }
 687         }
 688         return 0;
 689 }
 690
 691 struct ext4_xattr_block_find {
 692         struct ext4_xattr_search s;
 693         struct buffer_head *bh;
 694 };
 695
 696 static int
 697 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 698                       struct ext4_xattr_block_find *bs)
 699 {
 700         struct super_block *sb = inode->i_sb;
 701         int error;
 702
 703         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 704                   i->name_index, i->name, i->value, (long)i->value_len);
 705
 706         if (EXT4_I(inode)->i_file_acl) {
 707                 /* The inode already has an extended attribute block. */
 708                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 709                 error = -EIO;
 710                 if (!bs->bh)
 711                         goto cleanup;
 712                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 713                         atomic_read(&(bs->bh->b_count)),
 714                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 715                 if (ext4_xattr_check_block(inode, bs->bh)) {
 716                         EXT4_ERROR_INODE(inode, "bad block %llu",
 717                                          EXT4_I(inode)->i_file_acl);
 718                         error = -EIO;
 719                         goto cleanup;
 720                 }
 721                 /* Find the named attribute. */
 722                 bs->s.base = BHDR(bs->bh);
 723                 bs->s.first = BFIRST(bs->bh);
 724                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 725                 bs->s.here = bs->s.first;
 726                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 727                                               i->name, bs->bh->b_size, 1);
 728                 if (error && error != -ENODATA)
 729                         goto cleanup;
 730                 bs->s.not_found = error;
 731         }
 732         error = 0;
 733
 734 cleanup:
 735         return error;
 736 }
 737
 738 static int
 739 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 740                      struct ext4_xattr_info *i,
 741                      struct ext4_xattr_block_find *bs)
 742 {
 743         struct super_block *sb = inode->i_sb;
 744         struct buffer_head *new_bh = NULL;
 745         struct ext4_xattr_search *s = &bs->s;
 746         struct mb_cache_entry *ce = NULL;
 747         int error = 0;
 748
 749 #define header(x) ((struct ext4_xattr_header *)(x))
 750
 751         if (i->value && i->value_len > sb->s_blocksize)
 752                 return -ENOSPC;
 753         if (s->base) {
 754                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 755                                         bs->bh->b_blocknr);
 756                 error = ext4_journal_get_write_access(handle, bs->bh);
 757                 if (error)
 758                         goto cleanup;
 759                 lock_buffer(bs->bh);
 760
 761                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 762                         if (ce) {
 763                                 mb_cache_entry_free(ce);
 764                                 ce = NULL;
 765                         }
 766                         ea_bdebug(bs->bh, "modifying in-place");
 767                         error = ext4_xattr_set_entry(i, s);
 768                         if (!error) {
 769                                 if (!IS_LAST_ENTRY(s->first))
 770                                         ext4_xattr_rehash(header(s->base),
 771                                                           s->here);
 772                                 ext4_xattr_cache_insert(bs->bh);
 773                         }
 774                         unlock_buffer(bs->bh);
 775                         if (error == -EIO)
 776                                 goto bad_block;
 777                         if (!error)
 778                                 error = ext4_handle_dirty_xattr_block(handle,
 779                                                                       inode,
 780                                                                       bs->bh);
 781                         if (error)
 782                                 goto cleanup;
 783                         goto inserted;
 784                 } else {
 785                         int offset = (char *)s->here - bs->bh->b_data;
 786
 787                         unlock_buffer(bs->bh);
 788                         if (ce) {
 789                                 mb_cache_entry_release(ce);
 790                                 ce = NULL;
 791                         }
 792                         ea_bdebug(bs->bh, "cloning");
 793                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 794                         error = -ENOMEM;
 795                         if (s->base == NULL)
 796                                 goto cleanup;
 797                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 798                         s->first = ENTRY(header(s->base)+1);
 799                         header(s->base)->h_refcount = cpu_to_le32(1);
 800                         s->here = ENTRY(s->base + offset);
 801                         s->end = s->base + bs->bh->b_size;
 802                 }
 803         } else {
 804                 /* Allocate a buffer where we construct the new block. */
 805                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 806                 /* assert(header == s->base) */
 807                 error = -ENOMEM;
 808                 if (s->base == NULL)
 809                         goto cleanup;
 810                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 811                 header(s->base)->h_blocks = cpu_to_le32(1);
 812                 header(s->base)->h_refcount = cpu_to_le32(1);
 813                 s->first = ENTRY(header(s->base)+1);
 814                 s->here = ENTRY(header(s->base)+1);
 815                 s->end = s->base + sb->s_blocksize;
 816         }
 817
 818         error = ext4_xattr_set_entry(i, s);
 819         if (error == -EIO)
 820                 goto bad_block;
 821         if (error)
 822                 goto cleanup;
 823         if (!IS_LAST_ENTRY(s->first))
 824                 ext4_xattr_rehash(header(s->base), s->here);
 825
 826 inserted:
 827         if (!IS_LAST_ENTRY(s->first)) {
 828                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 829                 if (new_bh) {
 830                         /* We found an identical block in the cache. */
 831                         if (new_bh == bs->bh)
 832                                 ea_bdebug(new_bh, "keeping");
 833                         else {
 834                                 /* The old block is released after updating
 835                                    the inode. */
 836                                 error = dquot_alloc_block(inode,
 837                                                 EXT4_C2B(EXT4_SB(sb), 1));
 838                                 if (error)
 839                                         goto cleanup;
 840                                 error = ext4_journal_get_write_access(handle,
 841                                                                       new_bh);
 842                                 if (error)
 843                                         goto cleanup_dquot;
 844                                 lock_buffer(new_bh);
 845                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 846                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 847                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 848                                 unlock_buffer(new_bh);
 849                                 error = ext4_handle_dirty_xattr_block(handle,
 850                                                                       inode,
 851                                                                       new_bh);
 852                                 if (error)
 853                                         goto cleanup_dquot;
 854                         }
 855                         mb_cache_entry_release(ce);
 856                         ce = NULL;
 857                 } else if (bs->bh && s->base == bs->bh->b_data) {
 858                         /* We were modifying this block in-place. */
 859                         ea_bdebug(bs->bh, "keeping this block");
 860                         new_bh = bs->bh;
 861                         get_bh(new_bh);
 862                 } else {
 863                         /* We need to allocate a new block */
 864                         ext4_fsblk_t goal, block;
 865
 866                         goal = ext4_group_first_block_no(sb,
 867                                                 EXT4_I(inode)->i_block_group);
 868
 869                         /* non-extent files can't have physical blocks past 2^32 */
 870                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 871                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 872
 873                         /*
 874                          * take i_data_sem because we will test
 875                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 876                          */
 877                         down_read((&EXT4_I(inode)->i_data_sem));
 878                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 879                                                      NULL, &error);
 880                         up_read((&EXT4_I(inode)->i_data_sem));
 881                         if (error)
 882                                 goto cleanup;
 883
 884                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 885                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 886
 887                         ea_idebug(inode, "creating block %llu",
 888                                   (unsigned long long)block);
 889
 890                         new_bh = sb_getblk(sb, block);
 891                         if (unlikely(!new_bh)) {
 892                                 error = -ENOMEM;
 893 getblk_failed:
 894                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 895                                                  EXT4_FREE_BLOCKS_METADATA);
 896                                 goto cleanup;
 897                         }
 898                         lock_buffer(new_bh);
 899                         error = ext4_journal_get_create_access(handle, new_bh);
 900                         if (error) {
 901                                 unlock_buffer(new_bh);
 902                                 error = -EIO;
 903                                 goto getblk_failed;
 904                         }
 905                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 906                         set_buffer_uptodate(new_bh);
 907                         unlock_buffer(new_bh);
 908                         ext4_xattr_cache_insert(new_bh);
 909                         error = ext4_handle_dirty_xattr_block(handle,
 910                                                               inode, new_bh);
 911                         if (error)
 912                                 goto cleanup;
 913                 }
 914         }
 915
 916         /* Update the inode. */
 917         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 918
 919         /* Drop the previous xattr block. */
 920         if (bs->bh && bs->bh != new_bh)
 921                 ext4_xattr_release_block(handle, inode, bs->bh);
 922         error = 0;
 923
 924 cleanup:
 925         if (ce)
 926                 mb_cache_entry_release(ce);
 927         brelse(new_bh);
 928         if (!(bs->bh && s->base == bs->bh->b_data))
 929                 kfree(s->base);
 930
 931         return error;
 932
 933 cleanup_dquot:
 934         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 935         goto cleanup;
 936
 937 bad_block:
 938         EXT4_ERROR_INODE(inode, "bad block %llu",
 939                          EXT4_I(inode)->i_file_acl);
 940         goto cleanup;
 941
 942 #undef header
 943 }
 944
 945 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 946                           struct ext4_xattr_ibody_find *is)
 947 {
 948         struct ext4_xattr_ibody_header *header;
 949         struct ext4_inode *raw_inode;
 950         int error;
 951
 952         if (EXT4_I(inode)->i_extra_isize == 0)
 953                 return 0;
 954         raw_inode = ext4_raw_inode(&is->iloc);
 955         header = IHDR(inode, raw_inode);
 956         is->s.base = is->s.first = IFIRST(header);
 957         is->s.here = is->s.first;
 958         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 959         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 960                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 961                 if (error)
 962                         return error;
 963                 /* Find the named attribute. */
 964                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 965                                               i->name, is->s.end -
 966                                               (void *)is->s.base, 0);
 967                 if (error && error != -ENODATA)
 968                         return error;
 969                 is->s.not_found = error;
 970         }
 971         return 0;
 972 }
 973
 974 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 975                                 struct ext4_xattr_info *i,
 976                                 struct ext4_xattr_ibody_find *is)
 977 {
 978         struct ext4_xattr_ibody_header *header;
 979         struct ext4_xattr_search *s = &is->s;
 980         int error;
 981
 982         if (EXT4_I(inode)->i_extra_isize == 0)
 983                 return -ENOSPC;
 984         error = ext4_xattr_set_entry(i, s);
 985         if (error) {
 986                 if (error == -ENOSPC &&
 987                     ext4_has_inline_data(inode)) {
 988                         error = ext4_try_to_evict_inline_data(handle, inode,
 989                                         EXT4_XATTR_LEN(strlen(i->name) +
 990                                         EXT4_XATTR_SIZE(i->value_len)));
 991                         if (error)
 992                                 return error;
 993                         error = ext4_xattr_ibody_find(inode, i, is);
 994                         if (error)
 995                                 return error;
 996                         error = ext4_xattr_set_entry(i, s);
 997                 }
 998                 if (error)
 999                         return error;
1000         }
1001         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1002         if (!IS_LAST_ENTRY(s->first)) {
1003                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1004                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1005         } else {
1006                 header->h_magic = cpu_to_le32(0);
1007                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1008         }
1009         return 0;
1010 }
1011
1012 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1013                                 struct ext4_xattr_info *i,
1014                                 struct ext4_xattr_ibody_find *is)
1015 {
1016         struct ext4_xattr_ibody_header *header;
1017         struct ext4_xattr_search *s = &is->s;
1018         int error;
1019
1020         if (EXT4_I(inode)->i_extra_isize == 0)
1021                 return -ENOSPC;
1022         error = ext4_xattr_set_entry(i, s);
1023         if (error)
1024                 return error;
1025         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1026         if (!IS_LAST_ENTRY(s->first)) {
1027                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1028                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1029         } else {
1030                 header->h_magic = cpu_to_le32(0);
1031                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1032         }
1033         return 0;
1034 }
1035
1036 /*
1037  * ext4_xattr_set_handle()
1038  *
1039  * Create, replace or remove an extended attribute for this inode.  Value
1040  * is NULL to remove an existing extended attribute, and non-NULL to
1041  * either replace an existing extended attribute, or create a new extended
1042  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1043  * specify that an extended attribute must exist and must not exist
1044  * previous to the call, respectively.
1045  *
1046  * Returns 0, or a negative error number on failure.
1047  */
1048 int
1049 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1050                       const char *name, const void *value, size_t value_len,
1051                       int flags)
1052 {
1053         struct ext4_xattr_info i = {
1054                 .name_index = name_index,
1055                 .name = name,
1056                 .value = value,
1057                 .value_len = value_len,
1058
1059         };
1060         struct ext4_xattr_ibody_find is = {
1061                 .s = { .not_found = -ENODATA, },
1062         };
1063         struct ext4_xattr_block_find bs = {
1064                 .s = { .not_found = -ENODATA, },
1065         };
1066         unsigned long no_expand;
1067         int error;
1068
1069         if (!name)
1070                 return -EINVAL;
1071         if (strlen(name) > 255)
1072                 return -ERANGE;
1073         down_write(&EXT4_I(inode)->xattr_sem);
1074         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1075         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1076
1077         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1078         if (error)
1079                 goto cleanup;
1080
1081         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1082                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1083                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1084                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1085         }
1086
1087         error = ext4_xattr_ibody_find(inode, &i, &is);
1088         if (error)
1089                 goto cleanup;
1090         if (is.s.not_found)
1091                 error = ext4_xattr_block_find(inode, &i, &bs);
1092         if (error)
1093                 goto cleanup;
1094         if (is.s.not_found && bs.s.not_found) {
1095                 error = -ENODATA;
1096                 if (flags & XATTR_REPLACE)
1097                         goto cleanup;
1098                 error = 0;
1099                 if (!value)
1100                         goto cleanup;
1101         } else {
1102                 error = -EEXIST;
1103                 if (flags & XATTR_CREATE)
1104                         goto cleanup;
1105         }
1106         if (!value) {
1107                 if (!is.s.not_found)
1108                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1109                 else if (!bs.s.not_found)
1110                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1111         } else {
1112                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1113                 if (!error && !bs.s.not_found) {
1114                         i.value = NULL;
1115                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1116                 } else if (error == -ENOSPC) {
1117                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1118                                 error = ext4_xattr_block_find(inode, &i, &bs);
1119                                 if (error)
1120                                         goto cleanup;
1121                         }
1122                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1123                         if (error)
1124                                 goto cleanup;
1125                         if (!is.s.not_found) {
1126                                 i.value = NULL;
1127                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1128                                                              &is);
1129                         }
1130                 }
1131         }
1132         if (!error) {
1133                 ext4_xattr_update_super_block(handle, inode->i_sb);
1134                 inode->i_ctime = ext4_current_time(inode);
1135                 if (!value)
1136                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1137                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1138                 /*
1139                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1140                  * error != 0.
1141                  */
1142                 is.iloc.bh = NULL;
1143                 if (IS_SYNC(inode))
1144                         ext4_handle_sync(handle);
1145         }
1146
1147 cleanup:
1148         brelse(is.iloc.bh);
1149         brelse(bs.bh);
1150         if (no_expand == 0)
1151                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1152         up_write(&EXT4_I(inode)->xattr_sem);
1153         return error;
1154 }
1155
1156 /*
1157  * ext4_xattr_set()
1158  *
1159  * Like ext4_xattr_set_handle, but start from an inode. This extended
1160  * attribute modification is a filesystem transaction by itself.
1161  *
1162  * Returns 0, or a negative error number on failure.
1163  */
1164 int
1165 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1166                const void *value, size_t value_len, int flags)
1167 {
1168         handle_t *handle;
1169         int error, retries = 0;
1170         int credits = ext4_jbd2_credits_xattr(inode);
1171
1172 retry:
1173         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1174         if (IS_ERR(handle)) {
1175                 error = PTR_ERR(handle);
1176         } else {
1177                 int error2;
1178
1179                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1180                                               value, value_len, flags);
1181                 error2 = ext4_journal_stop(handle);
1182                 if (error == -ENOSPC &&
1183                     ext4_should_retry_alloc(inode->i_sb, &retries))
1184                         goto retry;
1185                 if (error == 0)
1186                         error = error2;
1187         }
1188
1189         return error;
1190 }
1191
1192 /*
1193  * Shift the EA entries in the inode to create space for the increased
1194  * i_extra_isize.
1195  */
1196 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1197                                      int value_offs_shift, void *to,
1198                                      void *from, size_t n, int blocksize)
1199 {
1200         struct ext4_xattr_entry *last = entry;
1201         int new_offs;
1202
1203         /* Adjust the value offsets of the entries */
1204         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1205                 if (!last->e_value_block && last->e_value_size) {
1206                         new_offs = le16_to_cpu(last->e_value_offs) +
1207                                                         value_offs_shift;
1208                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1209                                  > blocksize);
1210                         last->e_value_offs = cpu_to_le16(new_offs);
1211                 }
1212         }
1213         /* Shift the entries by n bytes */
1214         memmove(to, from, n);
1215 }
1216
1217 /*
1218  * Expand an inode by new_extra_isize bytes when EAs are present.
1219  * Returns 0 on success or negative error number on failure.
1220  */
1221 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1222                                struct ext4_inode *raw_inode, handle_t *handle)
1223 {
1224         struct ext4_xattr_ibody_header *header;
1225         struct ext4_xattr_entry *entry, *last, *first;
1226         struct buffer_head *bh = NULL;
1227         struct ext4_xattr_ibody_find *is = NULL;
1228         struct ext4_xattr_block_find *bs = NULL;
1229         char *buffer = NULL, *b_entry_name = NULL;
1230         size_t min_offs, free;
1231         int total_ino, total_blk;
1232         void *base, *start, *end;
1233         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1234         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1235
1236         down_write(&EXT4_I(inode)->xattr_sem);
1237 retry:
1238         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1239                 up_write(&EXT4_I(inode)->xattr_sem);
1240                 return 0;
1241         }
1242
1243         header = IHDR(inode, raw_inode);
1244         entry = IFIRST(header);
1245
1246         /*
1247          * Check if enough free space is available in the inode to shift the
1248          * entries ahead by new_extra_isize.
1249          */
1250
1251         base = start = entry;
1252         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1253         min_offs = end - base;
1254         last = entry;
1255         total_ino = sizeof(struct ext4_xattr_ibody_header);
1256
1257         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1258         if (free >= new_extra_isize) {
1259                 entry = IFIRST(header);
1260                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1261                                 - new_extra_isize, (void *)raw_inode +
1262                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1263                                 (void *)header, total_ino,
1264                                 inode->i_sb->s_blocksize);
1265                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1266                 error = 0;
1267                 goto cleanup;
1268         }
1269
1270         /*
1271          * Enough free space isn't available in the inode, check if
1272          * EA block can hold new_extra_isize bytes.
1273          */
1274         if (EXT4_I(inode)->i_file_acl) {
1275                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1276                 error = -EIO;
1277                 if (!bh)
1278                         goto cleanup;
1279                 if (ext4_xattr_check_block(inode, bh)) {
1280                         EXT4_ERROR_INODE(inode, "bad block %llu",
1281                                          EXT4_I(inode)->i_file_acl);
1282                         error = -EIO;
1283                         goto cleanup;
1284                 }
1285                 base = BHDR(bh);
1286                 first = BFIRST(bh);
1287                 end = bh->b_data + bh->b_size;
1288                 min_offs = end - base;
1289                 free = ext4_xattr_free_space(first, &min_offs, base,
1290                                              &total_blk);
1291                 if (free < new_extra_isize) {
1292                         if (!tried_min_extra_isize && s_min_extra_isize) {
1293                                 tried_min_extra_isize++;
1294                                 new_extra_isize = s_min_extra_isize;
1295                                 brelse(bh);
1296                                 goto retry;
1297                         }
1298                         error = -1;
1299                         goto cleanup;
1300                 }
1301         } else {
1302                 free = inode->i_sb->s_blocksize;
1303         }
1304
1305         while (new_extra_isize > 0) {
1306                 size_t offs, size, entry_size;
1307                 struct ext4_xattr_entry *small_entry = NULL;
1308                 struct ext4_xattr_info i = {
1309                         .value = NULL,
1310                         .value_len = 0,
1311                 };
1312                 unsigned int total_size;  /* EA entry size + value size */
1313                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1314                 unsigned int min_total_size = ~0U;
1315
1316                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1317                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1318                 if (!is || !bs) {
1319                         error = -ENOMEM;
1320                         goto cleanup;
1321                 }
1322
1323                 is->s.not_found = -ENODATA;
1324                 bs->s.not_found = -ENODATA;
1325                 is->iloc.bh = NULL;
1326                 bs->bh = NULL;
1327
1328                 last = IFIRST(header);
1329                 /* Find the entry best suited to be pushed into EA block */
1330                 entry = NULL;
1331                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1332                         total_size =
1333                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1334                                         EXT4_XATTR_LEN(last->e_name_len);
1335                         if (total_size <= free && total_size < min_total_size) {
1336                                 if (total_size < new_extra_isize) {
1337                                         small_entry = last;
1338                                 } else {
1339                                         entry = last;
1340                                         min_total_size = total_size;
1341                                 }
1342                         }
1343                 }
1344
1345                 if (entry == NULL) {
1346                         if (small_entry) {
1347                                 entry = small_entry;
1348                         } else {
1349                                 if (!tried_min_extra_isize &&
1350                                     s_min_extra_isize) {
1351                                         tried_min_extra_isize++;
1352                                         new_extra_isize = s_min_extra_isize;
1353                                         goto retry;
1354                                 }
1355                                 error = -1;
1356                                 goto cleanup;
1357                         }
1358                 }
1359                 offs = le16_to_cpu(entry->e_value_offs);
1360                 size = le32_to_cpu(entry->e_value_size);
1361                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1362                 i.name_index = entry->e_name_index,
1363                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1364                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1365                 if (!buffer || !b_entry_name) {
1366                         error = -ENOMEM;
1367                         goto cleanup;
1368                 }
1369                 /* Save the entry name and the entry value */
1370                 memcpy(buffer, (void *)IFIRST(header) + offs,
1371                        EXT4_XATTR_SIZE(size));
1372                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1373                 b_entry_name[entry->e_name_len] = '\0';
1374                 i.name = b_entry_name;
1375
1376                 error = ext4_get_inode_loc(inode, &is->iloc);
1377                 if (error)
1378                         goto cleanup;
1379
1380                 error = ext4_xattr_ibody_find(inode, &i, is);
1381                 if (error)
1382                         goto cleanup;
1383
1384                 /* Remove the chosen entry from the inode */
1385                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1386                 if (error)
1387                         goto cleanup;
1388
1389                 entry = IFIRST(header);
1390                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1391                         shift_bytes = new_extra_isize;
1392                 else
1393                         shift_bytes = entry_size + size;
1394                 /* Adjust the offsets and shift the remaining entries ahead */
1395                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1396                         shift_bytes, (void *)raw_inode +
1397                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1398                         (void *)header, total_ino - entry_size,
1399                         inode->i_sb->s_blocksize);
1400
1401                 extra_isize += shift_bytes;
1402                 new_extra_isize -= shift_bytes;
1403                 EXT4_I(inode)->i_extra_isize = extra_isize;
1404
1405                 i.name = b_entry_name;
1406                 i.value = buffer;
1407                 i.value_len = size;
1408                 error = ext4_xattr_block_find(inode, &i, bs);
1409                 if (error)
1410                         goto cleanup;
1411
1412                 /* Add entry which was removed from the inode into the block */
1413                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1414                 if (error)
1415                         goto cleanup;
1416                 kfree(b_entry_name);
1417                 kfree(buffer);
1418                 b_entry_name = NULL;
1419                 buffer = NULL;
1420                 brelse(is->iloc.bh);
1421                 kfree(is);
1422                 kfree(bs);
1423         }
1424         brelse(bh);
1425         up_write(&EXT4_I(inode)->xattr_sem);
1426         return 0;
1427
1428 cleanup:
1429         kfree(b_entry_name);
1430         kfree(buffer);
1431         if (is)
1432                 brelse(is->iloc.bh);
1433         kfree(is);
1434         kfree(bs);
1435         brelse(bh);
1436         up_write(&EXT4_I(inode)->xattr_sem);
1437         return error;
1438 }
1439
1440
1441
1442 /*
1443  * ext4_xattr_delete_inode()
1444  *
1445  * Free extended attribute resources associated with this inode. This
1446  * is called immediately before an inode is freed. We have exclusive
1447  * access to the inode.
1448  */
1449 void
1450 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1451 {
1452         struct buffer_head *bh = NULL;
1453
1454         if (!EXT4_I(inode)->i_file_acl)
1455                 goto cleanup;
1456         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1457         if (!bh) {
1458                 EXT4_ERROR_INODE(inode, "block %llu read error",
1459                                  EXT4_I(inode)->i_file_acl);
1460                 goto cleanup;
1461         }
1462         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1463             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1464                 EXT4_ERROR_INODE(inode, "bad block %llu",
1465                                  EXT4_I(inode)->i_file_acl);
1466                 goto cleanup;
1467         }
1468         ext4_xattr_release_block(handle, inode, bh);
1469         EXT4_I(inode)->i_file_acl = 0;
1470
1471 cleanup:
1472         brelse(bh);
1473 }
1474
1475 /*
1476  * ext4_xattr_put_super()
1477  *
1478  * This is called when a file system is unmounted.
1479  */
1480 void
1481 ext4_xattr_put_super(struct super_block *sb)
1482 {
1483         mb_cache_shrink(sb->s_bdev);
1484 }
1485
1486 /*
1487  * ext4_xattr_cache_insert()
1488  *
1489  * Create a new entry in the extended attribute cache, and insert
1490  * it unless such an entry is already in the cache.
1491  *
1492  * Returns 0, or a negative error number on failure.
1493  */
1494 static void
1495 ext4_xattr_cache_insert(struct buffer_head *bh)
1496 {
1497         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1498         struct mb_cache_entry *ce;
1499         int error;
1500
1501         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1502         if (!ce) {
1503                 ea_bdebug(bh, "out of memory");
1504                 return;
1505         }
1506         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1507         if (error) {
1508                 mb_cache_entry_free(ce);
1509                 if (error == -EBUSY) {
1510                         ea_bdebug(bh, "already in cache");
1511                         error = 0;
1512                 }
1513         } else {
1514                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1515                 mb_cache_entry_release(ce);
1516         }
1517 }
1518
1519 /*
1520  * ext4_xattr_cmp()
1521  *
1522  * Compare two extended attribute blocks for equality.
1523  *
1524  * Returns 0 if the blocks are equal, 1 if they differ, and
1525  * a negative error number on errors.
1526  */
1527 static int
1528 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1529                struct ext4_xattr_header *header2)
1530 {
1531         struct ext4_xattr_entry *entry1, *entry2;
1532
1533         entry1 = ENTRY(header1+1);
1534         entry2 = ENTRY(header2+1);
1535         while (!IS_LAST_ENTRY(entry1)) {
1536                 if (IS_LAST_ENTRY(entry2))
1537                         return 1;
1538                 if (entry1->e_hash != entry2->e_hash ||
1539                     entry1->e_name_index != entry2->e_name_index ||
1540                     entry1->e_name_len != entry2->e_name_len ||
1541                     entry1->e_value_size != entry2->e_value_size ||
1542                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1543                         return 1;
1544                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1545                         return -EIO;
1546                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1547                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1548                            le32_to_cpu(entry1->e_value_size)))
1549                         return 1;
1550
1551                 entry1 = EXT4_XATTR_NEXT(entry1);
1552                 entry2 = EXT4_XATTR_NEXT(entry2);
1553         }
1554         if (!IS_LAST_ENTRY(entry2))
1555                 return 1;
1556         return 0;
1557 }
1558
1559 /*
1560  * ext4_xattr_cache_find()
1561  *
1562  * Find an identical extended attribute block.
1563  *
1564  * Returns a pointer to the block found, or NULL if such a block was
1565  * not found or an error occurred.
1566  */
1567 static struct buffer_head *
1568 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1569                       struct mb_cache_entry **pce)
1570 {
1571         __u32 hash = le32_to_cpu(header->h_hash);
1572         struct mb_cache_entry *ce;
1573
1574         if (!header->h_hash)
1575                 return NULL;  /* never share */
1576         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1577 again:
1578         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1579                                        hash);
1580         while (ce) {
1581                 struct buffer_head *bh;
1582
1583                 if (IS_ERR(ce)) {
1584                         if (PTR_ERR(ce) == -EAGAIN)
1585                                 goto again;
1586                         break;
1587                 }
1588                 bh = sb_bread(inode->i_sb, ce->e_block);
1589                 if (!bh) {
1590                         EXT4_ERROR_INODE(inode, "block %lu read error",
1591                                          (unsigned long) ce->e_block);
1592                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1593                                 EXT4_XATTR_REFCOUNT_MAX) {
1594                         ea_idebug(inode, "block %lu refcount %d>=%d",
1595                                   (unsigned long) ce->e_block,
1596                                   le32_to_cpu(BHDR(bh)->h_refcount),
1597                                           EXT4_XATTR_REFCOUNT_MAX);
1598                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1599                         *pce = ce;
1600                         return bh;
1601                 }
1602                 brelse(bh);
1603                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1604         }
1605         return NULL;
1606 }
1607
1608 #define NAME_HASH_SHIFT 5
1609 #define VALUE_HASH_SHIFT 16
1610
1611 /*
1612  * ext4_xattr_hash_entry()
1613  *
1614  * Compute the hash of an extended attribute.
1615  */
1616 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1617                                          struct ext4_xattr_entry *entry)
1618 {
1619         __u32 hash = 0;
1620         char *name = entry->e_name;
1621         int n;
1622
1623         for (n = 0; n < entry->e_name_len; n++) {
1624                 hash = (hash << NAME_HASH_SHIFT) ^
1625                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1626                        *name++;
1627         }
1628
1629         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1630                 __le32 *value = (__le32 *)((char *)header +
1631                         le16_to_cpu(entry->e_value_offs));
1632                 for (n = (le32_to_cpu(entry->e_value_size) +
1633                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1634                         hash = (hash << VALUE_HASH_SHIFT) ^
1635                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1636                                le32_to_cpu(*value++);
1637                 }
1638         }
1639         entry->e_hash = cpu_to_le32(hash);
1640 }
1641
1642 #undef NAME_HASH_SHIFT
1643 #undef VALUE_HASH_SHIFT
1644
1645 #define BLOCK_HASH_SHIFT 16
1646
1647 /*
1648  * ext4_xattr_rehash()
1649  *
1650  * Re-compute the extended attribute hash value after an entry has changed.
1651  */
1652 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1653                               struct ext4_xattr_entry *entry)
1654 {
1655         struct ext4_xattr_entry *here;
1656         __u32 hash = 0;
1657
1658         ext4_xattr_hash_entry(header, entry);
1659         here = ENTRY(header+1);
1660         while (!IS_LAST_ENTRY(here)) {
1661                 if (!here->e_hash) {
1662                         /* Block is not shared if an entry's hash value == 0 */
1663                         hash = 0;
1664                         break;
1665                 }
1666                 hash = (hash << BLOCK_HASH_SHIFT) ^
1667                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1668                        le32_to_cpu(here->e_hash);
1669                 here = EXT4_XATTR_NEXT(here);
1670         }
1671         header->h_hash = cpu_to_le32(hash);
1672 }
1673
1674 #undef BLOCK_HASH_SHIFT
1675
1676 int __init
1677 ext4_init_xattr(void)
1678 {
1679         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1680         if (!ext4_xattr_cache)
1681                 return -ENOMEM;
1682         return 0;
1683 }
1684
1685 void
1686 ext4_exit_xattr(void)
1687 {
1688         if (ext4_xattr_cache)
1689                 mb_cache_destroy(ext4_xattr_cache);
1690         ext4_xattr_cache = NULL;
1691 }