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 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
  65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
  66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
  67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
  68
  69 #ifdef EXT4_XATTR_DEBUG
  70 # define ea_idebug(inode, f...) do { \
  71                 printk(KERN_DEBUG "inode %s:%lu: ", \
  72                         inode->i_sb->s_id, inode->i_ino); \
  73                 printk(f); \
  74                 printk("\n"); \
  75         } while (0)
  76 # define ea_bdebug(bh, f...) do { \
  77                 char b[BDEVNAME_SIZE]; \
  78                 printk(KERN_DEBUG "block %s:%lu: ", \
  79                         bdevname(bh->b_bdev, b), \
  80                         (unsigned long) bh->b_blocknr); \
  81                 printk(f); \
  82                 printk("\n"); \
  83         } while (0)
  84 #else
  85 # define ea_idebug(f...)
  86 # define ea_bdebug(f...)
  87 #endif
  88
  89 static void ext4_xattr_cache_insert(struct buffer_head *);
  90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  91                                                  struct ext4_xattr_header *,
  92                                                  struct mb_cache_entry **);
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  94                               struct ext4_xattr_entry *);
  95 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  96                            size_t buffer_size);
  97
  98 static struct mb_cache *ext4_xattr_cache;
  99
 100 static const struct xattr_handler *ext4_xattr_handler_map[] = {
 101         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 103         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
 104         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
 105 #endif
 106         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 107 #ifdef CONFIG_EXT4_FS_SECURITY
 108         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 109 #endif
 110 };
 111
 112 const struct xattr_handler *ext4_xattr_handlers[] = {
 113         &ext4_xattr_user_handler,
 114         &ext4_xattr_trusted_handler,
 115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 116         &ext4_xattr_acl_access_handler,
 117         &ext4_xattr_acl_default_handler,
 118 #endif
 119 #ifdef CONFIG_EXT4_FS_SECURITY
 120         &ext4_xattr_security_handler,
 121 #endif
 122         NULL
 123 };
 124
 125 static inline const struct xattr_handler *
 126 ext4_xattr_handler(int name_index)
 127 {
 128         const struct xattr_handler *handler = NULL;
 129
 130         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 131                 handler = ext4_xattr_handler_map[name_index];
 132         return handler;
 133 }
 134
 135 /*
 136  * Inode operation listxattr()
 137  *
 138  * dentry->d_inode->i_mutex: don't care
 139  */
 140 ssize_t
 141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 142 {
 143         return ext4_xattr_list(dentry, buffer, size);
 144 }
 145
 146 static int
 147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
 148                        void *value_start)
 149 {
 150         struct ext4_xattr_entry *e = entry;
 151
 152         while (!IS_LAST_ENTRY(e)) {
 153                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 154                 if ((void *)next >= end)
 155                         return -EIO;
 156                 e = next;
 157         }
 158
 159         while (!IS_LAST_ENTRY(entry)) {
 160                 if (entry->e_value_size != 0 &&
 161                     (value_start + le16_to_cpu(entry->e_value_offs) <
 162                      (void *)e + sizeof(__u32) ||
 163                      value_start + le16_to_cpu(entry->e_value_offs) +
 164                     le32_to_cpu(entry->e_value_size) > end))
 165                         return -EIO;
 166                 entry = EXT4_XATTR_NEXT(entry);
 167         }
 168
 169         return 0;
 170 }
 171
 172 static inline int
 173 ext4_xattr_check_block(struct buffer_head *bh)
 174 {
 175         int error;
 176
 177         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 178             BHDR(bh)->h_blocks != cpu_to_le32(1))
 179                 return -EIO;
 180         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
 181                                        bh->b_data);
 182         return error;
 183 }
 184
 185 static inline int
 186 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 187 {
 188         size_t value_size = le32_to_cpu(entry->e_value_size);
 189
 190         if (entry->e_value_block != 0 || value_size > size ||
 191             le16_to_cpu(entry->e_value_offs) + value_size > size)
 192                 return -EIO;
 193         return 0;
 194 }
 195
 196 static int
 197 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 198                       const char *name, size_t size, int sorted)
 199 {
 200         struct ext4_xattr_entry *entry;
 201         size_t name_len;
 202         int cmp = 1;
 203
 204         if (name == NULL)
 205                 return -EINVAL;
 206         name_len = strlen(name);
 207         entry = *pentry;
 208         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 209                 cmp = name_index - entry->e_name_index;
 210                 if (!cmp)
 211                         cmp = name_len - entry->e_name_len;
 212                 if (!cmp)
 213                         cmp = memcmp(name, entry->e_name, name_len);
 214                 if (cmp <= 0 && (sorted || cmp == 0))
 215                         break;
 216         }
 217         *pentry = entry;
 218         if (!cmp && ext4_xattr_check_entry(entry, size))
 219                         return -EIO;
 220         return cmp ? -ENODATA : 0;
 221 }
 222
 223 static int
 224 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 225                      void *buffer, size_t buffer_size)
 226 {
 227         struct buffer_head *bh = NULL;
 228         struct ext4_xattr_entry *entry;
 229         size_t size;
 230         int error;
 231
 232         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 233                   name_index, name, buffer, (long)buffer_size);
 234
 235         error = -ENODATA;
 236         if (!EXT4_I(inode)->i_file_acl)
 237                 goto cleanup;
 238         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
 239         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 240         if (!bh)
 241                 goto cleanup;
 242         ea_bdebug(bh, "b_count=%d, refcount=%d",
 243                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 244         if (ext4_xattr_check_block(bh)) {
 245 bad_block:
 246                 EXT4_ERROR_INODE(inode, "bad block %llu",
 247                                  EXT4_I(inode)->i_file_acl);
 248                 error = -EIO;
 249                 goto cleanup;
 250         }
 251         ext4_xattr_cache_insert(bh);
 252         entry = BFIRST(bh);
 253         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 254         if (error == -EIO)
 255                 goto bad_block;
 256         if (error)
 257                 goto cleanup;
 258         size = le32_to_cpu(entry->e_value_size);
 259         if (buffer) {
 260                 error = -ERANGE;
 261                 if (size > buffer_size)
 262                         goto cleanup;
 263                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 264                        size);
 265         }
 266         error = size;
 267
 268 cleanup:
 269         brelse(bh);
 270         return error;
 271 }
 272
 273 static int
 274 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 275                      void *buffer, size_t buffer_size)
 276 {
 277         struct ext4_xattr_ibody_header *header;
 278         struct ext4_xattr_entry *entry;
 279         struct ext4_inode *raw_inode;
 280         struct ext4_iloc iloc;
 281         size_t size;
 282         void *end;
 283         int error;
 284
 285         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 286                 return -ENODATA;
 287         error = ext4_get_inode_loc(inode, &iloc);
 288         if (error)
 289                 return error;
 290         raw_inode = ext4_raw_inode(&iloc);
 291         header = IHDR(inode, raw_inode);
 292         entry = IFIRST(header);
 293         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 294         error = ext4_xattr_check_names(entry, end, entry);
 295         if (error)
 296                 goto cleanup;
 297         error = ext4_xattr_find_entry(&entry, name_index, name,
 298                                       end - (void *)entry, 0);
 299         if (error)
 300                 goto cleanup;
 301         size = le32_to_cpu(entry->e_value_size);
 302         if (buffer) {
 303                 error = -ERANGE;
 304                 if (size > buffer_size)
 305                         goto cleanup;
 306                 memcpy(buffer, (void *)IFIRST(header) +
 307                        le16_to_cpu(entry->e_value_offs), size);
 308         }
 309         error = size;
 310
 311 cleanup:
 312         brelse(iloc.bh);
 313         return error;
 314 }
 315
 316 /*
 317  * ext4_xattr_get()
 318  *
 319  * Copy an extended attribute into the buffer
 320  * provided, or compute the buffer size required.
 321  * Buffer is NULL to compute the size of the buffer required.
 322  *
 323  * Returns a negative error number on failure, or the number of bytes
 324  * used / required on success.
 325  */
 326 int
 327 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 328                void *buffer, size_t buffer_size)
 329 {
 330         int error;
 331
 332         down_read(&EXT4_I(inode)->xattr_sem);
 333         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 334                                      buffer_size);
 335         if (error == -ENODATA)
 336                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 337                                              buffer_size);
 338         up_read(&EXT4_I(inode)->xattr_sem);
 339         return error;
 340 }
 341
 342 static int
 343 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 344                         char *buffer, size_t buffer_size)
 345 {
 346         size_t rest = buffer_size;
 347
 348         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 349                 const struct xattr_handler *handler =
 350                         ext4_xattr_handler(entry->e_name_index);
 351
 352                 if (handler) {
 353                         size_t size = handler->list(dentry, buffer, rest,
 354                                                     entry->e_name,
 355                                                     entry->e_name_len,
 356                                                     handler->flags);
 357                         if (buffer) {
 358                                 if (size > rest)
 359                                         return -ERANGE;
 360                                 buffer += size;
 361                         }
 362                         rest -= size;
 363                 }
 364         }
 365         return buffer_size - rest;
 366 }
 367
 368 static int
 369 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 370 {
 371         struct inode *inode = dentry->d_inode;
 372         struct buffer_head *bh = NULL;
 373         int error;
 374
 375         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 376                   buffer, (long)buffer_size);
 377
 378         error = 0;
 379         if (!EXT4_I(inode)->i_file_acl)
 380                 goto cleanup;
 381         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
 382         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 383         error = -EIO;
 384         if (!bh)
 385                 goto cleanup;
 386         ea_bdebug(bh, "b_count=%d, refcount=%d",
 387                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 388         if (ext4_xattr_check_block(bh)) {
 389                 EXT4_ERROR_INODE(inode, "bad block %llu",
 390                                  EXT4_I(inode)->i_file_acl);
 391                 error = -EIO;
 392                 goto cleanup;
 393         }
 394         ext4_xattr_cache_insert(bh);
 395         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 396
 397 cleanup:
 398         brelse(bh);
 399
 400         return error;
 401 }
 402
 403 static int
 404 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 405 {
 406         struct inode *inode = dentry->d_inode;
 407         struct ext4_xattr_ibody_header *header;
 408         struct ext4_inode *raw_inode;
 409         struct ext4_iloc iloc;
 410         void *end;
 411         int error;
 412
 413         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 414                 return 0;
 415         error = ext4_get_inode_loc(inode, &iloc);
 416         if (error)
 417                 return error;
 418         raw_inode = ext4_raw_inode(&iloc);
 419         header = IHDR(inode, raw_inode);
 420         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 421         error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
 422         if (error)
 423                 goto cleanup;
 424         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 425                                         buffer, buffer_size);
 426
 427 cleanup:
 428         brelse(iloc.bh);
 429         return error;
 430 }
 431
 432 /*
 433  * ext4_xattr_list()
 434  *
 435  * Copy a list of attribute names into the buffer
 436  * provided, or compute the buffer size required.
 437  * Buffer is NULL to compute the size of the buffer required.
 438  *
 439  * Returns a negative error number on failure, or the number of bytes
 440  * used / required on success.
 441  */
 442 static int
 443 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 444 {
 445         int ret, ret2;
 446
 447         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 448         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 449         if (ret < 0)
 450                 goto errout;
 451         if (buffer) {
 452                 buffer += ret;
 453                 buffer_size -= ret;
 454         }
 455         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 456         if (ret < 0)
 457                 goto errout;
 458         ret += ret2;
 459 errout:
 460         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 461         return ret;
 462 }
 463
 464 /*
 465  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 466  * not set, set it.
 467  */
 468 static void ext4_xattr_update_super_block(handle_t *handle,
 469                                           struct super_block *sb)
 470 {
 471         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 472                 return;
 473
 474         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 475                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 476                 ext4_handle_dirty_super(handle, sb);
 477         }
 478 }
 479
 480 /*
 481  * Release the xattr block BH: If the reference count is > 1, decrement
 482  * it; otherwise free the block.
 483  */
 484 static void
 485 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 486                          struct buffer_head *bh)
 487 {
 488         struct mb_cache_entry *ce = NULL;
 489         int error = 0;
 490
 491         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 492         error = ext4_journal_get_write_access(handle, bh);
 493         if (error)
 494                 goto out;
 495
 496         lock_buffer(bh);
 497         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 498                 ea_bdebug(bh, "refcount now=0; freeing");
 499                 if (ce)
 500                         mb_cache_entry_free(ce);
 501                 get_bh(bh);
 502                 ext4_free_blocks(handle, inode, bh, 0, 1,
 503                                  EXT4_FREE_BLOCKS_METADATA |
 504                                  EXT4_FREE_BLOCKS_FORGET);
 505                 unlock_buffer(bh);
 506         } else {
 507                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 508                 if (ce)
 509                         mb_cache_entry_release(ce);
 510                 unlock_buffer(bh);
 511                 error = ext4_handle_dirty_metadata(handle, inode, bh);
 512                 if (IS_SYNC(inode))
 513                         ext4_handle_sync(handle);
 514                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 515                 ea_bdebug(bh, "refcount now=%d; releasing",
 516                           le32_to_cpu(BHDR(bh)->h_refcount));
 517         }
 518 out:
 519         ext4_std_error(inode->i_sb, error);
 520         return;
 521 }
 522
 523 /*
 524  * Find the available free space for EAs. This also returns the total number of
 525  * bytes used by EA entries.
 526  */
 527 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 528                                     size_t *min_offs, void *base, int *total)
 529 {
 530         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 531                 *total += EXT4_XATTR_LEN(last->e_name_len);
 532                 if (!last->e_value_block && last->e_value_size) {
 533                         size_t offs = le16_to_cpu(last->e_value_offs);
 534                         if (offs < *min_offs)
 535                                 *min_offs = offs;
 536                 }
 537         }
 538         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 539 }
 540
 541 struct ext4_xattr_info {
 542         int name_index;
 543         const char *name;
 544         const void *value;
 545         size_t value_len;
 546 };
 547
 548 struct ext4_xattr_search {
 549         struct ext4_xattr_entry *first;
 550         void *base;
 551         void *end;
 552         struct ext4_xattr_entry *here;
 553         int not_found;
 554 };
 555
 556 static int
 557 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 558 {
 559         struct ext4_xattr_entry *last;
 560         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 561
 562         /* Compute min_offs and last. */
 563         last = s->first;
 564         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 565                 if (!last->e_value_block && last->e_value_size) {
 566                         size_t offs = le16_to_cpu(last->e_value_offs);
 567                         if (offs < min_offs)
 568                                 min_offs = offs;
 569                 }
 570         }
 571         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 572         if (!s->not_found) {
 573                 if (!s->here->e_value_block && s->here->e_value_size) {
 574                         size_t size = le32_to_cpu(s->here->e_value_size);
 575                         free += EXT4_XATTR_SIZE(size);
 576                 }
 577                 free += EXT4_XATTR_LEN(name_len);
 578         }
 579         if (i->value) {
 580                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 581                     free < EXT4_XATTR_LEN(name_len) +
 582                            EXT4_XATTR_SIZE(i->value_len))
 583                         return -ENOSPC;
 584         }
 585
 586         if (i->value && s->not_found) {
 587                 /* Insert the new name. */
 588                 size_t size = EXT4_XATTR_LEN(name_len);
 589                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 590                 memmove((void *)s->here + size, s->here, rest);
 591                 memset(s->here, 0, size);
 592                 s->here->e_name_index = i->name_index;
 593                 s->here->e_name_len = name_len;
 594                 memcpy(s->here->e_name, i->name, name_len);
 595         } else {
 596                 if (!s->here->e_value_block && s->here->e_value_size) {
 597                         void *first_val = s->base + min_offs;
 598                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 599                         void *val = s->base + offs;
 600                         size_t size = EXT4_XATTR_SIZE(
 601                                 le32_to_cpu(s->here->e_value_size));
 602
 603                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 604                                 /* The old and the new value have the same
 605                                    size. Just replace. */
 606                                 s->here->e_value_size =
 607                                         cpu_to_le32(i->value_len);
 608                                 memset(val + size - EXT4_XATTR_PAD, 0,
 609                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
 610                                 memcpy(val, i->value, i->value_len);
 611                                 return 0;
 612                         }
 613
 614                         /* Remove the old value. */
 615                         memmove(first_val + size, first_val, val - first_val);
 616                         memset(first_val, 0, size);
 617                         s->here->e_value_size = 0;
 618                         s->here->e_value_offs = 0;
 619                         min_offs += size;
 620
 621                         /* Adjust all value offsets. */
 622                         last = s->first;
 623                         while (!IS_LAST_ENTRY(last)) {
 624                                 size_t o = le16_to_cpu(last->e_value_offs);
 625                                 if (!last->e_value_block &&
 626                                     last->e_value_size && o < offs)
 627                                         last->e_value_offs =
 628                                                 cpu_to_le16(o + size);
 629                                 last = EXT4_XATTR_NEXT(last);
 630                         }
 631                 }
 632                 if (!i->value) {
 633                         /* Remove the old name. */
 634                         size_t size = EXT4_XATTR_LEN(name_len);
 635                         last = ENTRY((void *)last - size);
 636                         memmove(s->here, (void *)s->here + size,
 637                                 (void *)last - (void *)s->here + sizeof(__u32));
 638                         memset(last, 0, size);
 639                 }
 640         }
 641
 642         if (i->value) {
 643                 /* Insert the new value. */
 644                 s->here->e_value_size = cpu_to_le32(i->value_len);
 645                 if (i->value_len) {
 646                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 647                         void *val = s->base + min_offs - size;
 648                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 649                         memset(val + size - EXT4_XATTR_PAD, 0,
 650                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
 651                         memcpy(val, i->value, i->value_len);
 652                 }
 653         }
 654         return 0;
 655 }
 656
 657 struct ext4_xattr_block_find {
 658         struct ext4_xattr_search s;
 659         struct buffer_head *bh;
 660 };
 661
 662 static int
 663 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 664                       struct ext4_xattr_block_find *bs)
 665 {
 666         struct super_block *sb = inode->i_sb;
 667         int error;
 668
 669         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 670                   i->name_index, i->name, i->value, (long)i->value_len);
 671
 672         if (EXT4_I(inode)->i_file_acl) {
 673                 /* The inode already has an extended attribute block. */
 674                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 675                 error = -EIO;
 676                 if (!bs->bh)
 677                         goto cleanup;
 678                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 679                         atomic_read(&(bs->bh->b_count)),
 680                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 681                 if (ext4_xattr_check_block(bs->bh)) {
 682                         EXT4_ERROR_INODE(inode, "bad block %llu",
 683                                          EXT4_I(inode)->i_file_acl);
 684                         error = -EIO;
 685                         goto cleanup;
 686                 }
 687                 /* Find the named attribute. */
 688                 bs->s.base = BHDR(bs->bh);
 689                 bs->s.first = BFIRST(bs->bh);
 690                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 691                 bs->s.here = bs->s.first;
 692                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 693                                               i->name, bs->bh->b_size, 1);
 694                 if (error && error != -ENODATA)
 695                         goto cleanup;
 696                 bs->s.not_found = error;
 697         }
 698         error = 0;
 699
 700 cleanup:
 701         return error;
 702 }
 703
 704 static int
 705 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 706                      struct ext4_xattr_info *i,
 707                      struct ext4_xattr_block_find *bs)
 708 {
 709         struct super_block *sb = inode->i_sb;
 710         struct buffer_head *new_bh = NULL;
 711         struct ext4_xattr_search *s = &bs->s;
 712         struct mb_cache_entry *ce = NULL;
 713         int error = 0;
 714
 715 #define header(x) ((struct ext4_xattr_header *)(x))
 716
 717         if (i->value && i->value_len > sb->s_blocksize)
 718                 return -ENOSPC;
 719         if (s->base) {
 720                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 721                                         bs->bh->b_blocknr);
 722                 error = ext4_journal_get_write_access(handle, bs->bh);
 723                 if (error)
 724                         goto cleanup;
 725                 lock_buffer(bs->bh);
 726
 727                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 728                         if (ce) {
 729                                 mb_cache_entry_free(ce);
 730                                 ce = NULL;
 731                         }
 732                         ea_bdebug(bs->bh, "modifying in-place");
 733                         error = ext4_xattr_set_entry(i, s);
 734                         if (!error) {
 735                                 if (!IS_LAST_ENTRY(s->first))
 736                                         ext4_xattr_rehash(header(s->base),
 737                                                           s->here);
 738                                 ext4_xattr_cache_insert(bs->bh);
 739                         }
 740                         unlock_buffer(bs->bh);
 741                         if (error == -EIO)
 742                                 goto bad_block;
 743                         if (!error)
 744                                 error = ext4_handle_dirty_metadata(handle,
 745                                                                    inode,
 746                                                                    bs->bh);
 747                         if (error)
 748                                 goto cleanup;
 749                         goto inserted;
 750                 } else {
 751                         int offset = (char *)s->here - bs->bh->b_data;
 752
 753                         unlock_buffer(bs->bh);
 754                         ext4_handle_release_buffer(handle, bs->bh);
 755                         if (ce) {
 756                                 mb_cache_entry_release(ce);
 757                                 ce = NULL;
 758                         }
 759                         ea_bdebug(bs->bh, "cloning");
 760                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 761                         error = -ENOMEM;
 762                         if (s->base == NULL)
 763                                 goto cleanup;
 764                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 765                         s->first = ENTRY(header(s->base)+1);
 766                         header(s->base)->h_refcount = cpu_to_le32(1);
 767                         s->here = ENTRY(s->base + offset);
 768                         s->end = s->base + bs->bh->b_size;
 769                 }
 770         } else {
 771                 /* Allocate a buffer where we construct the new block. */
 772                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 773                 /* assert(header == s->base) */
 774                 error = -ENOMEM;
 775                 if (s->base == NULL)
 776                         goto cleanup;
 777                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 778                 header(s->base)->h_blocks = cpu_to_le32(1);
 779                 header(s->base)->h_refcount = cpu_to_le32(1);
 780                 s->first = ENTRY(header(s->base)+1);
 781                 s->here = ENTRY(header(s->base)+1);
 782                 s->end = s->base + sb->s_blocksize;
 783         }
 784
 785         error = ext4_xattr_set_entry(i, s);
 786         if (error == -EIO)
 787                 goto bad_block;
 788         if (error)
 789                 goto cleanup;
 790         if (!IS_LAST_ENTRY(s->first))
 791                 ext4_xattr_rehash(header(s->base), s->here);
 792
 793 inserted:
 794         if (!IS_LAST_ENTRY(s->first)) {
 795                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 796                 if (new_bh) {
 797                         /* We found an identical block in the cache. */
 798                         if (new_bh == bs->bh)
 799                                 ea_bdebug(new_bh, "keeping");
 800                         else {
 801                                 /* The old block is released after updating
 802                                    the inode. */
 803                                 error = dquot_alloc_block(inode,
 804                                                 EXT4_C2B(EXT4_SB(sb), 1));
 805                                 if (error)
 806                                         goto cleanup;
 807                                 error = ext4_journal_get_write_access(handle,
 808                                                                       new_bh);
 809                                 if (error)
 810                                         goto cleanup_dquot;
 811                                 lock_buffer(new_bh);
 812                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 813                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 814                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 815                                 unlock_buffer(new_bh);
 816                                 error = ext4_handle_dirty_metadata(handle,
 817                                                                    inode,
 818                                                                    new_bh);
 819                                 if (error)
 820                                         goto cleanup_dquot;
 821                         }
 822                         mb_cache_entry_release(ce);
 823                         ce = NULL;
 824                 } else if (bs->bh && s->base == bs->bh->b_data) {
 825                         /* We were modifying this block in-place. */
 826                         ea_bdebug(bs->bh, "keeping this block");
 827                         new_bh = bs->bh;
 828                         get_bh(new_bh);
 829                 } else {
 830                         /* We need to allocate a new block */
 831                         ext4_fsblk_t goal, block;
 832
 833                         goal = ext4_group_first_block_no(sb,
 834                                                 EXT4_I(inode)->i_block_group);
 835
 836                         /* non-extent files can't have physical blocks past 2^32 */
 837                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 838                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 839
 840                         /*
 841                          * take i_data_sem because we will test
 842                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 843                          */
 844                         down_read((&EXT4_I(inode)->i_data_sem));
 845                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 846                                                      NULL, &error);
 847                         up_read((&EXT4_I(inode)->i_data_sem));
 848                         if (error)
 849                                 goto cleanup;
 850
 851                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 852                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 853
 854                         ea_idebug(inode, "creating block %d", block);
 855
 856                         new_bh = sb_getblk(sb, block);
 857                         if (!new_bh) {
 858                                 error = -ENOMEM;
 859 getblk_failed:
 860                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 861                                                  EXT4_FREE_BLOCKS_METADATA);
 862                                 goto cleanup;
 863                         }
 864                         lock_buffer(new_bh);
 865                         error = ext4_journal_get_create_access(handle, new_bh);
 866                         if (error) {
 867                                 unlock_buffer(new_bh);
 868                                 error = -EIO;
 869                                 goto getblk_failed;
 870                         }
 871                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 872                         set_buffer_uptodate(new_bh);
 873                         unlock_buffer(new_bh);
 874                         ext4_xattr_cache_insert(new_bh);
 875                         error = ext4_handle_dirty_metadata(handle,
 876                                                            inode, new_bh);
 877                         if (error)
 878                                 goto cleanup;
 879                 }
 880         }
 881
 882         /* Update the inode. */
 883         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 884
 885         /* Drop the previous xattr block. */
 886         if (bs->bh && bs->bh != new_bh)
 887                 ext4_xattr_release_block(handle, inode, bs->bh);
 888         error = 0;
 889
 890 cleanup:
 891         if (ce)
 892                 mb_cache_entry_release(ce);
 893         brelse(new_bh);
 894         if (!(bs->bh && s->base == bs->bh->b_data))
 895                 kfree(s->base);
 896
 897         return error;
 898
 899 cleanup_dquot:
 900         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 901         goto cleanup;
 902
 903 bad_block:
 904         EXT4_ERROR_INODE(inode, "bad block %llu",
 905                          EXT4_I(inode)->i_file_acl);
 906         goto cleanup;
 907
 908 #undef header
 909 }
 910
 911 struct ext4_xattr_ibody_find {
 912         struct ext4_xattr_search s;
 913         struct ext4_iloc iloc;
 914 };
 915
 916 static int
 917 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 918                       struct ext4_xattr_ibody_find *is)
 919 {
 920         struct ext4_xattr_ibody_header *header;
 921         struct ext4_inode *raw_inode;
 922         int error;
 923
 924         if (EXT4_I(inode)->i_extra_isize == 0)
 925                 return 0;
 926         raw_inode = ext4_raw_inode(&is->iloc);
 927         header = IHDR(inode, raw_inode);
 928         is->s.base = is->s.first = IFIRST(header);
 929         is->s.here = is->s.first;
 930         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 931         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 932                 error = ext4_xattr_check_names(IFIRST(header), is->s.end,
 933                                                IFIRST(header));
 934                 if (error)
 935                         return error;
 936                 /* Find the named attribute. */
 937                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 938                                               i->name, is->s.end -
 939                                               (void *)is->s.base, 0);
 940                 if (error && error != -ENODATA)
 941                         return error;
 942                 is->s.not_found = error;
 943         }
 944         return 0;
 945 }
 946
 947 static int
 948 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 949                      struct ext4_xattr_info *i,
 950                      struct ext4_xattr_ibody_find *is)
 951 {
 952         struct ext4_xattr_ibody_header *header;
 953         struct ext4_xattr_search *s = &is->s;
 954         int error;
 955
 956         if (EXT4_I(inode)->i_extra_isize == 0)
 957                 return -ENOSPC;
 958         error = ext4_xattr_set_entry(i, s);
 959         if (error)
 960                 return error;
 961         header = IHDR(inode, ext4_raw_inode(&is->iloc));
 962         if (!IS_LAST_ENTRY(s->first)) {
 963                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 964                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
 965         } else {
 966                 header->h_magic = cpu_to_le32(0);
 967                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
 968         }
 969         return 0;
 970 }
 971
 972 /*
 973  * ext4_xattr_set_handle()
 974  *
 975  * Create, replace or remove an extended attribute for this inode.  Value
 976  * is NULL to remove an existing extended attribute, and non-NULL to
 977  * either replace an existing extended attribute, or create a new extended
 978  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
 979  * specify that an extended attribute must exist and must not exist
 980  * previous to the call, respectively.
 981  *
 982  * Returns 0, or a negative error number on failure.
 983  */
 984 int
 985 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 986                       const char *name, const void *value, size_t value_len,
 987                       int flags)
 988 {
 989         struct ext4_xattr_info i = {
 990                 .name_index = name_index,
 991                 .name = name,
 992                 .value = value,
 993                 .value_len = value_len,
 994
 995         };
 996         struct ext4_xattr_ibody_find is = {
 997                 .s = { .not_found = -ENODATA, },
 998         };
 999         struct ext4_xattr_block_find bs = {
1000                 .s = { .not_found = -ENODATA, },
1001         };
1002         unsigned long no_expand;
1003         int error;
1004
1005         if (!name)
1006                 return -EINVAL;
1007         if (strlen(name) > 255)
1008                 return -ERANGE;
1009         down_write(&EXT4_I(inode)->xattr_sem);
1010         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1011         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1012
1013         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1014         if (error)
1015                 goto cleanup;
1016
1017         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1018                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1019                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1020                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1021         }
1022
1023         error = ext4_xattr_ibody_find(inode, &i, &is);
1024         if (error)
1025                 goto cleanup;
1026         if (is.s.not_found)
1027                 error = ext4_xattr_block_find(inode, &i, &bs);
1028         if (error)
1029                 goto cleanup;
1030         if (is.s.not_found && bs.s.not_found) {
1031                 error = -ENODATA;
1032                 if (flags & XATTR_REPLACE)
1033                         goto cleanup;
1034                 error = 0;
1035                 if (!value)
1036                         goto cleanup;
1037         } else {
1038                 error = -EEXIST;
1039                 if (flags & XATTR_CREATE)
1040                         goto cleanup;
1041         }
1042         if (!value) {
1043                 if (!is.s.not_found)
1044                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1045                 else if (!bs.s.not_found)
1046                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1047         } else {
1048                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1049                 if (!error && !bs.s.not_found) {
1050                         i.value = NULL;
1051                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1052                 } else if (error == -ENOSPC) {
1053                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1054                                 error = ext4_xattr_block_find(inode, &i, &bs);
1055                                 if (error)
1056                                         goto cleanup;
1057                         }
1058                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1059                         if (error)
1060                                 goto cleanup;
1061                         if (!is.s.not_found) {
1062                                 i.value = NULL;
1063                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1064                                                              &is);
1065                         }
1066                 }
1067         }
1068         if (!error) {
1069                 ext4_xattr_update_super_block(handle, inode->i_sb);
1070                 inode->i_ctime = ext4_current_time(inode);
1071                 if (!value)
1072                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1073                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1074                 /*
1075                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1076                  * error != 0.
1077                  */
1078                 is.iloc.bh = NULL;
1079                 if (IS_SYNC(inode))
1080                         ext4_handle_sync(handle);
1081         }
1082
1083 cleanup:
1084         brelse(is.iloc.bh);
1085         brelse(bs.bh);
1086         if (no_expand == 0)
1087                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1088         up_write(&EXT4_I(inode)->xattr_sem);
1089         return error;
1090 }
1091
1092 /*
1093  * ext4_xattr_set()
1094  *
1095  * Like ext4_xattr_set_handle, but start from an inode. This extended
1096  * attribute modification is a filesystem transaction by itself.
1097  *
1098  * Returns 0, or a negative error number on failure.
1099  */
1100 int
1101 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1102                const void *value, size_t value_len, int flags)
1103 {
1104         handle_t *handle;
1105         int error, retries = 0;
1106
1107 retry:
1108         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1109         if (IS_ERR(handle)) {
1110                 error = PTR_ERR(handle);
1111         } else {
1112                 int error2;
1113
1114                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1115                                               value, value_len, flags);
1116                 error2 = ext4_journal_stop(handle);
1117                 if (error == -ENOSPC &&
1118                     ext4_should_retry_alloc(inode->i_sb, &retries))
1119                         goto retry;
1120                 if (error == 0)
1121                         error = error2;
1122         }
1123
1124         return error;
1125 }
1126
1127 /*
1128  * Shift the EA entries in the inode to create space for the increased
1129  * i_extra_isize.
1130  */
1131 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1132                                      int value_offs_shift, void *to,
1133                                      void *from, size_t n, int blocksize)
1134 {
1135         struct ext4_xattr_entry *last = entry;
1136         int new_offs;
1137
1138         /* Adjust the value offsets of the entries */
1139         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1140                 if (!last->e_value_block && last->e_value_size) {
1141                         new_offs = le16_to_cpu(last->e_value_offs) +
1142                                                         value_offs_shift;
1143                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1144                                  > blocksize);
1145                         last->e_value_offs = cpu_to_le16(new_offs);
1146                 }
1147         }
1148         /* Shift the entries by n bytes */
1149         memmove(to, from, n);
1150 }
1151
1152 /*
1153  * Expand an inode by new_extra_isize bytes when EAs are present.
1154  * Returns 0 on success or negative error number on failure.
1155  */
1156 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1157                                struct ext4_inode *raw_inode, handle_t *handle)
1158 {
1159         struct ext4_xattr_ibody_header *header;
1160         struct ext4_xattr_entry *entry, *last, *first;
1161         struct buffer_head *bh = NULL;
1162         struct ext4_xattr_ibody_find *is = NULL;
1163         struct ext4_xattr_block_find *bs = NULL;
1164         char *buffer = NULL, *b_entry_name = NULL;
1165         size_t min_offs, free;
1166         int total_ino, total_blk;
1167         void *base, *start, *end;
1168         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1169         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1170
1171         down_write(&EXT4_I(inode)->xattr_sem);
1172 retry:
1173         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1174                 up_write(&EXT4_I(inode)->xattr_sem);
1175                 return 0;
1176         }
1177
1178         header = IHDR(inode, raw_inode);
1179         entry = IFIRST(header);
1180
1181         /*
1182          * Check if enough free space is available in the inode to shift the
1183          * entries ahead by new_extra_isize.
1184          */
1185
1186         base = start = entry;
1187         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1188         min_offs = end - base;
1189         last = entry;
1190         total_ino = sizeof(struct ext4_xattr_ibody_header);
1191
1192         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1193         if (free >= new_extra_isize) {
1194                 entry = IFIRST(header);
1195                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1196                                 - new_extra_isize, (void *)raw_inode +
1197                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1198                                 (void *)header, total_ino,
1199                                 inode->i_sb->s_blocksize);
1200                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1201                 error = 0;
1202                 goto cleanup;
1203         }
1204
1205         /*
1206          * Enough free space isn't available in the inode, check if
1207          * EA block can hold new_extra_isize bytes.
1208          */
1209         if (EXT4_I(inode)->i_file_acl) {
1210                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1211                 error = -EIO;
1212                 if (!bh)
1213                         goto cleanup;
1214                 if (ext4_xattr_check_block(bh)) {
1215                         EXT4_ERROR_INODE(inode, "bad block %llu",
1216                                          EXT4_I(inode)->i_file_acl);
1217                         error = -EIO;
1218                         goto cleanup;
1219                 }
1220                 base = BHDR(bh);
1221                 first = BFIRST(bh);
1222                 end = bh->b_data + bh->b_size;
1223                 min_offs = end - base;
1224                 free = ext4_xattr_free_space(first, &min_offs, base,
1225                                              &total_blk);
1226                 if (free < new_extra_isize) {
1227                         if (!tried_min_extra_isize && s_min_extra_isize) {
1228                                 tried_min_extra_isize++;
1229                                 new_extra_isize = s_min_extra_isize;
1230                                 brelse(bh);
1231                                 goto retry;
1232                         }
1233                         error = -1;
1234                         goto cleanup;
1235                 }
1236         } else {
1237                 free = inode->i_sb->s_blocksize;
1238         }
1239
1240         while (new_extra_isize > 0) {
1241                 size_t offs, size, entry_size;
1242                 struct ext4_xattr_entry *small_entry = NULL;
1243                 struct ext4_xattr_info i = {
1244                         .value = NULL,
1245                         .value_len = 0,
1246                 };
1247                 unsigned int total_size;  /* EA entry size + value size */
1248                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1249                 unsigned int min_total_size = ~0U;
1250
1251                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1252                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1253                 if (!is || !bs) {
1254                         error = -ENOMEM;
1255                         goto cleanup;
1256                 }
1257
1258                 is->s.not_found = -ENODATA;
1259                 bs->s.not_found = -ENODATA;
1260                 is->iloc.bh = NULL;
1261                 bs->bh = NULL;
1262
1263                 last = IFIRST(header);
1264                 /* Find the entry best suited to be pushed into EA block */
1265                 entry = NULL;
1266                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1267                         total_size =
1268                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1269                                         EXT4_XATTR_LEN(last->e_name_len);
1270                         if (total_size <= free && total_size < min_total_size) {
1271                                 if (total_size < new_extra_isize) {
1272                                         small_entry = last;
1273                                 } else {
1274                                         entry = last;
1275                                         min_total_size = total_size;
1276                                 }
1277                         }
1278                 }
1279
1280                 if (entry == NULL) {
1281                         if (small_entry) {
1282                                 entry = small_entry;
1283                         } else {
1284                                 if (!tried_min_extra_isize &&
1285                                     s_min_extra_isize) {
1286                                         tried_min_extra_isize++;
1287                                         new_extra_isize = s_min_extra_isize;
1288                                         kfree(is); is = NULL;
1289                                         kfree(bs); bs = NULL;
1290                                         brelse(bh);
1291                                         goto retry;
1292                                 }
1293                                 error = -1;
1294                                 goto cleanup;
1295                         }
1296                 }
1297                 offs = le16_to_cpu(entry->e_value_offs);
1298                 size = le32_to_cpu(entry->e_value_size);
1299                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1300                 i.name_index = entry->e_name_index,
1301                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1302                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1303                 if (!buffer || !b_entry_name) {
1304                         error = -ENOMEM;
1305                         goto cleanup;
1306                 }
1307                 /* Save the entry name and the entry value */
1308                 memcpy(buffer, (void *)IFIRST(header) + offs,
1309                        EXT4_XATTR_SIZE(size));
1310                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1311                 b_entry_name[entry->e_name_len] = '\0';
1312                 i.name = b_entry_name;
1313
1314                 error = ext4_get_inode_loc(inode, &is->iloc);
1315                 if (error)
1316                         goto cleanup;
1317
1318                 error = ext4_xattr_ibody_find(inode, &i, is);
1319                 if (error)
1320                         goto cleanup;
1321
1322                 /* Remove the chosen entry from the inode */
1323                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1324                 if (error)
1325                         goto cleanup;
1326
1327                 entry = IFIRST(header);
1328                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1329                         shift_bytes = new_extra_isize;
1330                 else
1331                         shift_bytes = entry_size + size;
1332                 /* Adjust the offsets and shift the remaining entries ahead */
1333                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1334                         shift_bytes, (void *)raw_inode +
1335                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1336                         (void *)header, total_ino - entry_size,
1337                         inode->i_sb->s_blocksize);
1338
1339                 extra_isize += shift_bytes;
1340                 new_extra_isize -= shift_bytes;
1341                 EXT4_I(inode)->i_extra_isize = extra_isize;
1342
1343                 i.name = b_entry_name;
1344                 i.value = buffer;
1345                 i.value_len = size;
1346                 error = ext4_xattr_block_find(inode, &i, bs);
1347                 if (error)
1348                         goto cleanup;
1349
1350                 /* Add entry which was removed from the inode into the block */
1351                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1352                 if (error)
1353                         goto cleanup;
1354                 kfree(b_entry_name);
1355                 kfree(buffer);
1356                 b_entry_name = NULL;
1357                 buffer = NULL;
1358                 brelse(is->iloc.bh);
1359                 kfree(is);
1360                 kfree(bs);
1361         }
1362         brelse(bh);
1363         up_write(&EXT4_I(inode)->xattr_sem);
1364         return 0;
1365
1366 cleanup:
1367         kfree(b_entry_name);
1368         kfree(buffer);
1369         if (is)
1370                 brelse(is->iloc.bh);
1371         kfree(is);
1372         kfree(bs);
1373         brelse(bh);
1374         up_write(&EXT4_I(inode)->xattr_sem);
1375         return error;
1376 }
1377
1378
1379
1380 /*
1381  * ext4_xattr_delete_inode()
1382  *
1383  * Free extended attribute resources associated with this inode. This
1384  * is called immediately before an inode is freed. We have exclusive
1385  * access to the inode.
1386  */
1387 void
1388 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1389 {
1390         struct buffer_head *bh = NULL;
1391
1392         if (!EXT4_I(inode)->i_file_acl)
1393                 goto cleanup;
1394         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1395         if (!bh) {
1396                 EXT4_ERROR_INODE(inode, "block %llu read error",
1397                                  EXT4_I(inode)->i_file_acl);
1398                 goto cleanup;
1399         }
1400         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1401             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1402                 EXT4_ERROR_INODE(inode, "bad block %llu",
1403                                  EXT4_I(inode)->i_file_acl);
1404                 goto cleanup;
1405         }
1406         ext4_xattr_release_block(handle, inode, bh);
1407         EXT4_I(inode)->i_file_acl = 0;
1408
1409 cleanup:
1410         brelse(bh);
1411 }
1412
1413 /*
1414  * ext4_xattr_put_super()
1415  *
1416  * This is called when a file system is unmounted.
1417  */
1418 void
1419 ext4_xattr_put_super(struct super_block *sb)
1420 {
1421         mb_cache_shrink(sb->s_bdev);
1422 }
1423
1424 /*
1425  * ext4_xattr_cache_insert()
1426  *
1427  * Create a new entry in the extended attribute cache, and insert
1428  * it unless such an entry is already in the cache.
1429  *
1430  * Returns 0, or a negative error number on failure.
1431  */
1432 static void
1433 ext4_xattr_cache_insert(struct buffer_head *bh)
1434 {
1435         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1436         struct mb_cache_entry *ce;
1437         int error;
1438
1439         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1440         if (!ce) {
1441                 ea_bdebug(bh, "out of memory");
1442                 return;
1443         }
1444         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1445         if (error) {
1446                 mb_cache_entry_free(ce);
1447                 if (error == -EBUSY) {
1448                         ea_bdebug(bh, "already in cache");
1449                         error = 0;
1450                 }
1451         } else {
1452                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1453                 mb_cache_entry_release(ce);
1454         }
1455 }
1456
1457 /*
1458  * ext4_xattr_cmp()
1459  *
1460  * Compare two extended attribute blocks for equality.
1461  *
1462  * Returns 0 if the blocks are equal, 1 if they differ, and
1463  * a negative error number on errors.
1464  */
1465 static int
1466 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1467                struct ext4_xattr_header *header2)
1468 {
1469         struct ext4_xattr_entry *entry1, *entry2;
1470
1471         entry1 = ENTRY(header1+1);
1472         entry2 = ENTRY(header2+1);
1473         while (!IS_LAST_ENTRY(entry1)) {
1474                 if (IS_LAST_ENTRY(entry2))
1475                         return 1;
1476                 if (entry1->e_hash != entry2->e_hash ||
1477                     entry1->e_name_index != entry2->e_name_index ||
1478                     entry1->e_name_len != entry2->e_name_len ||
1479                     entry1->e_value_size != entry2->e_value_size ||
1480                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1481                         return 1;
1482                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1483                         return -EIO;
1484                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1485                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1486                            le32_to_cpu(entry1->e_value_size)))
1487                         return 1;
1488
1489                 entry1 = EXT4_XATTR_NEXT(entry1);
1490                 entry2 = EXT4_XATTR_NEXT(entry2);
1491         }
1492         if (!IS_LAST_ENTRY(entry2))
1493                 return 1;
1494         return 0;
1495 }
1496
1497 /*
1498  * ext4_xattr_cache_find()
1499  *
1500  * Find an identical extended attribute block.
1501  *
1502  * Returns a pointer to the block found, or NULL if such a block was
1503  * not found or an error occurred.
1504  */
1505 static struct buffer_head *
1506 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1507                       struct mb_cache_entry **pce)
1508 {
1509         __u32 hash = le32_to_cpu(header->h_hash);
1510         struct mb_cache_entry *ce;
1511
1512         if (!header->h_hash)
1513                 return NULL;  /* never share */
1514         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1515 again:
1516         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1517                                        hash);
1518         while (ce) {
1519                 struct buffer_head *bh;
1520
1521                 if (IS_ERR(ce)) {
1522                         if (PTR_ERR(ce) == -EAGAIN)
1523                                 goto again;
1524                         break;
1525                 }
1526                 bh = sb_bread(inode->i_sb, ce->e_block);
1527                 if (!bh) {
1528                         EXT4_ERROR_INODE(inode, "block %lu read error",
1529                                          (unsigned long) ce->e_block);
1530                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1531                                 EXT4_XATTR_REFCOUNT_MAX) {
1532                         ea_idebug(inode, "block %lu refcount %d>=%d",
1533                                   (unsigned long) ce->e_block,
1534                                   le32_to_cpu(BHDR(bh)->h_refcount),
1535                                           EXT4_XATTR_REFCOUNT_MAX);
1536                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1537                         *pce = ce;
1538                         return bh;
1539                 }
1540                 brelse(bh);
1541                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1542         }
1543         return NULL;
1544 }
1545
1546 #define NAME_HASH_SHIFT 5
1547 #define VALUE_HASH_SHIFT 16
1548
1549 /*
1550  * ext4_xattr_hash_entry()
1551  *
1552  * Compute the hash of an extended attribute.
1553  */
1554 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1555                                          struct ext4_xattr_entry *entry)
1556 {
1557         __u32 hash = 0;
1558         char *name = entry->e_name;
1559         int n;
1560
1561         for (n = 0; n < entry->e_name_len; n++) {
1562                 hash = (hash << NAME_HASH_SHIFT) ^
1563                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1564                        *name++;
1565         }
1566
1567         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1568                 __le32 *value = (__le32 *)((char *)header +
1569                         le16_to_cpu(entry->e_value_offs));
1570                 for (n = (le32_to_cpu(entry->e_value_size) +
1571                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1572                         hash = (hash << VALUE_HASH_SHIFT) ^
1573                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1574                                le32_to_cpu(*value++);
1575                 }
1576         }
1577         entry->e_hash = cpu_to_le32(hash);
1578 }
1579
1580 #undef NAME_HASH_SHIFT
1581 #undef VALUE_HASH_SHIFT
1582
1583 #define BLOCK_HASH_SHIFT 16
1584
1585 /*
1586  * ext4_xattr_rehash()
1587  *
1588  * Re-compute the extended attribute hash value after an entry has changed.
1589  */
1590 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1591                               struct ext4_xattr_entry *entry)
1592 {
1593         struct ext4_xattr_entry *here;
1594         __u32 hash = 0;
1595
1596         ext4_xattr_hash_entry(header, entry);
1597         here = ENTRY(header+1);
1598         while (!IS_LAST_ENTRY(here)) {
1599                 if (!here->e_hash) {
1600                         /* Block is not shared if an entry's hash value == 0 */
1601                         hash = 0;
1602                         break;
1603                 }
1604                 hash = (hash << BLOCK_HASH_SHIFT) ^
1605                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1606                        le32_to_cpu(here->e_hash);
1607                 here = EXT4_XATTR_NEXT(here);
1608         }
1609         header->h_hash = cpu_to_le32(hash);
1610 }
1611
1612 #undef BLOCK_HASH_SHIFT
1613
1614 int __init
1615 ext4_init_xattr(void)
1616 {
1617         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1618         if (!ext4_xattr_cache)
1619                 return -ENOMEM;
1620         return 0;
1621 }
1622
1623 void
1624 ext4_exit_xattr(void)
1625 {
1626         if (ext4_xattr_cache)
1627                 mb_cache_destroy(ext4_xattr_cache);
1628         ext4_xattr_cache = NULL;
1629 }