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 it;
 521  * 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                 unlock_buffer(bh);
 542                 ext4_free_blocks(handle, inode, bh, 0, 1,
 543                                  EXT4_FREE_BLOCKS_METADATA |
 544                                  EXT4_FREE_BLOCKS_FORGET);
 545         } else {
 546                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 547                 if (ce)
 548                         mb_cache_entry_release(ce);
 549                 /*
 550                  * Beware of this ugliness: Releasing of xattr block references
 551                  * from different inodes can race and so we have to protect
 552                  * from a race where someone else frees the block (and releases
 553                  * its journal_head) before we are done dirtying the buffer. In
 554                  * nojournal mode this race is harmless and we actually cannot
 555                  * call ext4_handle_dirty_xattr_block() with locked buffer as
 556                  * that function can call sync_dirty_buffer() so for that case
 557                  * we handle the dirtying after unlocking the buffer.
 558                  */
 559                 if (ext4_handle_valid(handle))
 560                         error = ext4_handle_dirty_xattr_block(handle, inode,
 561                                                               bh);
 562                 unlock_buffer(bh);
 563                 if (!ext4_handle_valid(handle))
 564                         error = ext4_handle_dirty_xattr_block(handle, inode,
 565                                                               bh);
 566                 if (IS_SYNC(inode))
 567                         ext4_handle_sync(handle);
 568                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 569                 ea_bdebug(bh, "refcount now=%d; releasing",
 570                           le32_to_cpu(BHDR(bh)->h_refcount));
 571         }
 572 out:
 573         ext4_std_error(inode->i_sb, error);
 574         return;
 575 }
 576
 577 /*
 578  * Find the available free space for EAs. This also returns the total number of
 579  * bytes used by EA entries.
 580  */
 581 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 582                                     size_t *min_offs, void *base, int *total)
 583 {
 584         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 585                 *total += EXT4_XATTR_LEN(last->e_name_len);
 586                 if (!last->e_value_block && last->e_value_size) {
 587                         size_t offs = le16_to_cpu(last->e_value_offs);
 588                         if (offs < *min_offs)
 589                                 *min_offs = offs;
 590                 }
 591         }
 592         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 593 }
 594
 595 static int
 596 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 597 {
 598         struct ext4_xattr_entry *last;
 599         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 600
 601         /* Compute min_offs and last. */
 602         last = s->first;
 603         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 604                 if (!last->e_value_block && last->e_value_size) {
 605                         size_t offs = le16_to_cpu(last->e_value_offs);
 606                         if (offs < min_offs)
 607                                 min_offs = offs;
 608                 }
 609         }
 610         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 611         if (!s->not_found) {
 612                 if (!s->here->e_value_block && s->here->e_value_size) {
 613                         size_t size = le32_to_cpu(s->here->e_value_size);
 614                         free += EXT4_XATTR_SIZE(size);
 615                 }
 616                 free += EXT4_XATTR_LEN(name_len);
 617         }
 618         if (i->value) {
 619                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 620                     free < EXT4_XATTR_LEN(name_len) +
 621                            EXT4_XATTR_SIZE(i->value_len))
 622                         return -ENOSPC;
 623         }
 624
 625         if (i->value && s->not_found) {
 626                 /* Insert the new name. */
 627                 size_t size = EXT4_XATTR_LEN(name_len);
 628                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 629                 memmove((void *)s->here + size, s->here, rest);
 630                 memset(s->here, 0, size);
 631                 s->here->e_name_index = i->name_index;
 632                 s->here->e_name_len = name_len;
 633                 memcpy(s->here->e_name, i->name, name_len);
 634         } else {
 635                 if (!s->here->e_value_block && s->here->e_value_size) {
 636                         void *first_val = s->base + min_offs;
 637                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 638                         void *val = s->base + offs;
 639                         size_t size = EXT4_XATTR_SIZE(
 640                                 le32_to_cpu(s->here->e_value_size));
 641
 642                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 643                                 /* The old and the new value have the same
 644                                    size. Just replace. */
 645                                 s->here->e_value_size =
 646                                         cpu_to_le32(i->value_len);
 647                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 648                                         memset(val, 0, size);
 649                                 } else {
 650                                         /* Clear pad bytes first. */
 651                                         memset(val + size - EXT4_XATTR_PAD, 0,
 652                                                EXT4_XATTR_PAD);
 653                                         memcpy(val, i->value, i->value_len);
 654                                 }
 655                                 return 0;
 656                         }
 657
 658                         /* Remove the old value. */
 659                         memmove(first_val + size, first_val, val - first_val);
 660                         memset(first_val, 0, size);
 661                         s->here->e_value_size = 0;
 662                         s->here->e_value_offs = 0;
 663                         min_offs += size;
 664
 665                         /* Adjust all value offsets. */
 666                         last = s->first;
 667                         while (!IS_LAST_ENTRY(last)) {
 668                                 size_t o = le16_to_cpu(last->e_value_offs);
 669                                 if (!last->e_value_block &&
 670                                     last->e_value_size && o < offs)
 671                                         last->e_value_offs =
 672                                                 cpu_to_le16(o + size);
 673                                 last = EXT4_XATTR_NEXT(last);
 674                         }
 675                 }
 676                 if (!i->value) {
 677                         /* Remove the old name. */
 678                         size_t size = EXT4_XATTR_LEN(name_len);
 679                         last = ENTRY((void *)last - size);
 680                         memmove(s->here, (void *)s->here + size,
 681                                 (void *)last - (void *)s->here + sizeof(__u32));
 682                         memset(last, 0, size);
 683                 }
 684         }
 685
 686         if (i->value) {
 687                 /* Insert the new value. */
 688                 s->here->e_value_size = cpu_to_le32(i->value_len);
 689                 if (i->value_len) {
 690                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 691                         void *val = s->base + min_offs - size;
 692                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 693                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 694                                 memset(val, 0, size);
 695                         } else {
 696                                 /* Clear the pad bytes first. */
 697                                 memset(val + size - EXT4_XATTR_PAD, 0,
 698                                        EXT4_XATTR_PAD);
 699                                 memcpy(val, i->value, i->value_len);
 700                         }
 701                 }
 702         }
 703         return 0;
 704 }
 705
 706 struct ext4_xattr_block_find {
 707         struct ext4_xattr_search s;
 708         struct buffer_head *bh;
 709 };
 710
 711 static int
 712 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 713                       struct ext4_xattr_block_find *bs)
 714 {
 715         struct super_block *sb = inode->i_sb;
 716         int error;
 717
 718         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 719                   i->name_index, i->name, i->value, (long)i->value_len);
 720
 721         if (EXT4_I(inode)->i_file_acl) {
 722                 /* The inode already has an extended attribute block. */
 723                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 724                 error = -EIO;
 725                 if (!bs->bh)
 726                         goto cleanup;
 727                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 728                         atomic_read(&(bs->bh->b_count)),
 729                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 730                 if (ext4_xattr_check_block(inode, bs->bh)) {
 731                         EXT4_ERROR_INODE(inode, "bad block %llu",
 732                                          EXT4_I(inode)->i_file_acl);
 733                         error = -EIO;
 734                         goto cleanup;
 735                 }
 736                 /* Find the named attribute. */
 737                 bs->s.base = BHDR(bs->bh);
 738                 bs->s.first = BFIRST(bs->bh);
 739                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 740                 bs->s.here = bs->s.first;
 741                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 742                                               i->name, bs->bh->b_size, 1);
 743                 if (error && error != -ENODATA)
 744                         goto cleanup;
 745                 bs->s.not_found = error;
 746         }
 747         error = 0;
 748
 749 cleanup:
 750         return error;
 751 }
 752
 753 static int
 754 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 755                      struct ext4_xattr_info *i,
 756                      struct ext4_xattr_block_find *bs)
 757 {
 758         struct super_block *sb = inode->i_sb;
 759         struct buffer_head *new_bh = NULL;
 760         struct ext4_xattr_search *s = &bs->s;
 761         struct mb_cache_entry *ce = NULL;
 762         int error = 0;
 763
 764 #define header(x) ((struct ext4_xattr_header *)(x))
 765
 766         if (i->value && i->value_len > sb->s_blocksize)
 767                 return -ENOSPC;
 768         if (s->base) {
 769                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 770                                         bs->bh->b_blocknr);
 771                 error = ext4_journal_get_write_access(handle, bs->bh);
 772                 if (error)
 773                         goto cleanup;
 774                 lock_buffer(bs->bh);
 775
 776                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 777                         if (ce) {
 778                                 mb_cache_entry_free(ce);
 779                                 ce = NULL;
 780                         }
 781                         ea_bdebug(bs->bh, "modifying in-place");
 782                         error = ext4_xattr_set_entry(i, s);
 783                         if (!error) {
 784                                 if (!IS_LAST_ENTRY(s->first))
 785                                         ext4_xattr_rehash(header(s->base),
 786                                                           s->here);
 787                                 ext4_xattr_cache_insert(bs->bh);
 788                         }
 789                         unlock_buffer(bs->bh);
 790                         if (error == -EIO)
 791                                 goto bad_block;
 792                         if (!error)
 793                                 error = ext4_handle_dirty_xattr_block(handle,
 794                                                                       inode,
 795                                                                       bs->bh);
 796                         if (error)
 797                                 goto cleanup;
 798                         goto inserted;
 799                 } else {
 800                         int offset = (char *)s->here - bs->bh->b_data;
 801
 802                         unlock_buffer(bs->bh);
 803                         if (ce) {
 804                                 mb_cache_entry_release(ce);
 805                                 ce = NULL;
 806                         }
 807                         ea_bdebug(bs->bh, "cloning");
 808                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 809                         error = -ENOMEM;
 810                         if (s->base == NULL)
 811                                 goto cleanup;
 812                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 813                         s->first = ENTRY(header(s->base)+1);
 814                         header(s->base)->h_refcount = cpu_to_le32(1);
 815                         s->here = ENTRY(s->base + offset);
 816                         s->end = s->base + bs->bh->b_size;
 817                 }
 818         } else {
 819                 /* Allocate a buffer where we construct the new block. */
 820                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 821                 /* assert(header == s->base) */
 822                 error = -ENOMEM;
 823                 if (s->base == NULL)
 824                         goto cleanup;
 825                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 826                 header(s->base)->h_blocks = cpu_to_le32(1);
 827                 header(s->base)->h_refcount = cpu_to_le32(1);
 828                 s->first = ENTRY(header(s->base)+1);
 829                 s->here = ENTRY(header(s->base)+1);
 830                 s->end = s->base + sb->s_blocksize;
 831         }
 832
 833         error = ext4_xattr_set_entry(i, s);
 834         if (error == -EIO)
 835                 goto bad_block;
 836         if (error)
 837                 goto cleanup;
 838         if (!IS_LAST_ENTRY(s->first))
 839                 ext4_xattr_rehash(header(s->base), s->here);
 840
 841 inserted:
 842         if (!IS_LAST_ENTRY(s->first)) {
 843                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 844                 if (new_bh) {
 845                         /* We found an identical block in the cache. */
 846                         if (new_bh == bs->bh)
 847                                 ea_bdebug(new_bh, "keeping");
 848                         else {
 849                                 /* The old block is released after updating
 850                                    the inode. */
 851                                 error = dquot_alloc_block(inode,
 852                                                 EXT4_C2B(EXT4_SB(sb), 1));
 853                                 if (error)
 854                                         goto cleanup;
 855                                 error = ext4_journal_get_write_access(handle,
 856                                                                       new_bh);
 857                                 if (error)
 858                                         goto cleanup_dquot;
 859                                 lock_buffer(new_bh);
 860                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 861                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 862                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 863                                 unlock_buffer(new_bh);
 864                                 error = ext4_handle_dirty_xattr_block(handle,
 865                                                                       inode,
 866                                                                       new_bh);
 867                                 if (error)
 868                                         goto cleanup_dquot;
 869                         }
 870                         mb_cache_entry_release(ce);
 871                         ce = NULL;
 872                 } else if (bs->bh && s->base == bs->bh->b_data) {
 873                         /* We were modifying this block in-place. */
 874                         ea_bdebug(bs->bh, "keeping this block");
 875                         new_bh = bs->bh;
 876                         get_bh(new_bh);
 877                 } else {
 878                         /* We need to allocate a new block */
 879                         ext4_fsblk_t goal, block;
 880
 881                         goal = ext4_group_first_block_no(sb,
 882                                                 EXT4_I(inode)->i_block_group);
 883
 884                         /* non-extent files can't have physical blocks past 2^32 */
 885                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 886                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 887
 888                         /*
 889                          * take i_data_sem because we will test
 890                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 891                          */
 892                         down_read((&EXT4_I(inode)->i_data_sem));
 893                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 894                                                      NULL, &error);
 895                         up_read((&EXT4_I(inode)->i_data_sem));
 896                         if (error)
 897                                 goto cleanup;
 898
 899                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 900                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 901
 902                         ea_idebug(inode, "creating block %llu",
 903                                   (unsigned long long)block);
 904
 905                         new_bh = sb_getblk(sb, block);
 906                         if (unlikely(!new_bh)) {
 907                                 error = -ENOMEM;
 908 getblk_failed:
 909                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 910                                                  EXT4_FREE_BLOCKS_METADATA);
 911                                 goto cleanup;
 912                         }
 913                         lock_buffer(new_bh);
 914                         error = ext4_journal_get_create_access(handle, new_bh);
 915                         if (error) {
 916                                 unlock_buffer(new_bh);
 917                                 error = -EIO;
 918                                 goto getblk_failed;
 919                         }
 920                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 921                         set_buffer_uptodate(new_bh);
 922                         unlock_buffer(new_bh);
 923                         ext4_xattr_cache_insert(new_bh);
 924                         error = ext4_handle_dirty_xattr_block(handle,
 925                                                               inode, new_bh);
 926                         if (error)
 927                                 goto cleanup;
 928                 }
 929         }
 930
 931         /* Update the inode. */
 932         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 933
 934         /* Drop the previous xattr block. */
 935         if (bs->bh && bs->bh != new_bh)
 936                 ext4_xattr_release_block(handle, inode, bs->bh);
 937         error = 0;
 938
 939 cleanup:
 940         if (ce)
 941                 mb_cache_entry_release(ce);
 942         brelse(new_bh);
 943         if (!(bs->bh && s->base == bs->bh->b_data))
 944                 kfree(s->base);
 945
 946         return error;
 947
 948 cleanup_dquot:
 949         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 950         goto cleanup;
 951
 952 bad_block:
 953         EXT4_ERROR_INODE(inode, "bad block %llu",
 954                          EXT4_I(inode)->i_file_acl);
 955         goto cleanup;
 956
 957 #undef header
 958 }
 959
 960 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 961                           struct ext4_xattr_ibody_find *is)
 962 {
 963         struct ext4_xattr_ibody_header *header;
 964         struct ext4_inode *raw_inode;
 965         int error;
 966
 967         if (EXT4_I(inode)->i_extra_isize == 0)
 968                 return 0;
 969         raw_inode = ext4_raw_inode(&is->iloc);
 970         header = IHDR(inode, raw_inode);
 971         is->s.base = is->s.first = IFIRST(header);
 972         is->s.here = is->s.first;
 973         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 974         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 975                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 976                 if (error)
 977                         return error;
 978                 /* Find the named attribute. */
 979                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 980                                               i->name, is->s.end -
 981                                               (void *)is->s.base, 0);
 982                 if (error && error != -ENODATA)
 983                         return error;
 984                 is->s.not_found = error;
 985         }
 986         return 0;
 987 }
 988
 989 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 990                                 struct ext4_xattr_info *i,
 991                                 struct ext4_xattr_ibody_find *is)
 992 {
 993         struct ext4_xattr_ibody_header *header;
 994         struct ext4_xattr_search *s = &is->s;
 995         int error;
 996
 997         if (EXT4_I(inode)->i_extra_isize == 0)
 998                 return -ENOSPC;
 999         error = ext4_xattr_set_entry(i, s);
1000         if (error) {
1001                 if (error == -ENOSPC &&
1002                     ext4_has_inline_data(inode)) {
1003                         error = ext4_try_to_evict_inline_data(handle, inode,
1004                                         EXT4_XATTR_LEN(strlen(i->name) +
1005                                         EXT4_XATTR_SIZE(i->value_len)));
1006                         if (error)
1007                                 return error;
1008                         error = ext4_xattr_ibody_find(inode, i, is);
1009                         if (error)
1010                                 return error;
1011                         error = ext4_xattr_set_entry(i, s);
1012                 }
1013                 if (error)
1014                         return error;
1015         }
1016         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1017         if (!IS_LAST_ENTRY(s->first)) {
1018                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1019                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1020         } else {
1021                 header->h_magic = cpu_to_le32(0);
1022                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1023         }
1024         return 0;
1025 }
1026
1027 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1028                                 struct ext4_xattr_info *i,
1029                                 struct ext4_xattr_ibody_find *is)
1030 {
1031         struct ext4_xattr_ibody_header *header;
1032         struct ext4_xattr_search *s = &is->s;
1033         int error;
1034
1035         if (EXT4_I(inode)->i_extra_isize == 0)
1036                 return -ENOSPC;
1037         error = ext4_xattr_set_entry(i, s);
1038         if (error)
1039                 return error;
1040         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1041         if (!IS_LAST_ENTRY(s->first)) {
1042                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1043                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1044         } else {
1045                 header->h_magic = cpu_to_le32(0);
1046                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1047         }
1048         return 0;
1049 }
1050
1051 /*
1052  * ext4_xattr_set_handle()
1053  *
1054  * Create, replace or remove an extended attribute for this inode.  Value
1055  * is NULL to remove an existing extended attribute, and non-NULL to
1056  * either replace an existing extended attribute, or create a new extended
1057  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1058  * specify that an extended attribute must exist and must not exist
1059  * previous to the call, respectively.
1060  *
1061  * Returns 0, or a negative error number on failure.
1062  */
1063 int
1064 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1065                       const char *name, const void *value, size_t value_len,
1066                       int flags)
1067 {
1068         struct ext4_xattr_info i = {
1069                 .name_index = name_index,
1070                 .name = name,
1071                 .value = value,
1072                 .value_len = value_len,
1073
1074         };
1075         struct ext4_xattr_ibody_find is = {
1076                 .s = { .not_found = -ENODATA, },
1077         };
1078         struct ext4_xattr_block_find bs = {
1079                 .s = { .not_found = -ENODATA, },
1080         };
1081         unsigned long no_expand;
1082         int error;
1083
1084         if (!name)
1085                 return -EINVAL;
1086         if (strlen(name) > 255)
1087                 return -ERANGE;
1088         down_write(&EXT4_I(inode)->xattr_sem);
1089         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1090         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1091
1092         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1093         if (error)
1094                 goto cleanup;
1095
1096         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1097                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1098                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1099                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1100         }
1101
1102         error = ext4_xattr_ibody_find(inode, &i, &is);
1103         if (error)
1104                 goto cleanup;
1105         if (is.s.not_found)
1106                 error = ext4_xattr_block_find(inode, &i, &bs);
1107         if (error)
1108                 goto cleanup;
1109         if (is.s.not_found && bs.s.not_found) {
1110                 error = -ENODATA;
1111                 if (flags & XATTR_REPLACE)
1112                         goto cleanup;
1113                 error = 0;
1114                 if (!value)
1115                         goto cleanup;
1116         } else {
1117                 error = -EEXIST;
1118                 if (flags & XATTR_CREATE)
1119                         goto cleanup;
1120         }
1121         if (!value) {
1122                 if (!is.s.not_found)
1123                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1124                 else if (!bs.s.not_found)
1125                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1126         } else {
1127                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1128                 if (!error && !bs.s.not_found) {
1129                         i.value = NULL;
1130                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1131                 } else if (error == -ENOSPC) {
1132                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1133                                 error = ext4_xattr_block_find(inode, &i, &bs);
1134                                 if (error)
1135                                         goto cleanup;
1136                         }
1137                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1138                         if (error)
1139                                 goto cleanup;
1140                         if (!is.s.not_found) {
1141                                 i.value = NULL;
1142                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1143                                                              &is);
1144                         }
1145                 }
1146         }
1147         if (!error) {
1148                 ext4_xattr_update_super_block(handle, inode->i_sb);
1149                 inode->i_ctime = ext4_current_time(inode);
1150                 if (!value)
1151                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1152                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1153                 /*
1154                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1155                  * error != 0.
1156                  */
1157                 is.iloc.bh = NULL;
1158                 if (IS_SYNC(inode))
1159                         ext4_handle_sync(handle);
1160         }
1161
1162 cleanup:
1163         brelse(is.iloc.bh);
1164         brelse(bs.bh);
1165         if (no_expand == 0)
1166                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1167         up_write(&EXT4_I(inode)->xattr_sem);
1168         return error;
1169 }
1170
1171 /*
1172  * ext4_xattr_set()
1173  *
1174  * Like ext4_xattr_set_handle, but start from an inode. This extended
1175  * attribute modification is a filesystem transaction by itself.
1176  *
1177  * Returns 0, or a negative error number on failure.
1178  */
1179 int
1180 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1181                const void *value, size_t value_len, int flags)
1182 {
1183         handle_t *handle;
1184         int error, retries = 0;
1185         int credits = ext4_jbd2_credits_xattr(inode);
1186
1187 retry:
1188         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1189         if (IS_ERR(handle)) {
1190                 error = PTR_ERR(handle);
1191         } else {
1192                 int error2;
1193
1194                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1195                                               value, value_len, flags);
1196                 error2 = ext4_journal_stop(handle);
1197                 if (error == -ENOSPC &&
1198                     ext4_should_retry_alloc(inode->i_sb, &retries))
1199                         goto retry;
1200                 if (error == 0)
1201                         error = error2;
1202         }
1203
1204         return error;
1205 }
1206
1207 /*
1208  * Shift the EA entries in the inode to create space for the increased
1209  * i_extra_isize.
1210  */
1211 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1212                                      int value_offs_shift, void *to,
1213                                      void *from, size_t n, int blocksize)
1214 {
1215         struct ext4_xattr_entry *last = entry;
1216         int new_offs;
1217
1218         /* Adjust the value offsets of the entries */
1219         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1220                 if (!last->e_value_block && last->e_value_size) {
1221                         new_offs = le16_to_cpu(last->e_value_offs) +
1222                                                         value_offs_shift;
1223                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1224                                  > blocksize);
1225                         last->e_value_offs = cpu_to_le16(new_offs);
1226                 }
1227         }
1228         /* Shift the entries by n bytes */
1229         memmove(to, from, n);
1230 }
1231
1232 /*
1233  * Expand an inode by new_extra_isize bytes when EAs are present.
1234  * Returns 0 on success or negative error number on failure.
1235  */
1236 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1237                                struct ext4_inode *raw_inode, handle_t *handle)
1238 {
1239         struct ext4_xattr_ibody_header *header;
1240         struct ext4_xattr_entry *entry, *last, *first;
1241         struct buffer_head *bh = NULL;
1242         struct ext4_xattr_ibody_find *is = NULL;
1243         struct ext4_xattr_block_find *bs = NULL;
1244         char *buffer = NULL, *b_entry_name = NULL;
1245         size_t min_offs, free;
1246         int total_ino, total_blk;
1247         void *base, *start, *end;
1248         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1249         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1250
1251         down_write(&EXT4_I(inode)->xattr_sem);
1252 retry:
1253         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1254                 up_write(&EXT4_I(inode)->xattr_sem);
1255                 return 0;
1256         }
1257
1258         header = IHDR(inode, raw_inode);
1259         entry = IFIRST(header);
1260
1261         /*
1262          * Check if enough free space is available in the inode to shift the
1263          * entries ahead by new_extra_isize.
1264          */
1265
1266         base = start = entry;
1267         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1268         min_offs = end - base;
1269         last = entry;
1270         total_ino = sizeof(struct ext4_xattr_ibody_header);
1271
1272         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1273         if (free >= new_extra_isize) {
1274                 entry = IFIRST(header);
1275                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1276                                 - new_extra_isize, (void *)raw_inode +
1277                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1278                                 (void *)header, total_ino,
1279                                 inode->i_sb->s_blocksize);
1280                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1281                 error = 0;
1282                 goto cleanup;
1283         }
1284
1285         /*
1286          * Enough free space isn't available in the inode, check if
1287          * EA block can hold new_extra_isize bytes.
1288          */
1289         if (EXT4_I(inode)->i_file_acl) {
1290                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1291                 error = -EIO;
1292                 if (!bh)
1293                         goto cleanup;
1294                 if (ext4_xattr_check_block(inode, bh)) {
1295                         EXT4_ERROR_INODE(inode, "bad block %llu",
1296                                          EXT4_I(inode)->i_file_acl);
1297                         error = -EIO;
1298                         goto cleanup;
1299                 }
1300                 base = BHDR(bh);
1301                 first = BFIRST(bh);
1302                 end = bh->b_data + bh->b_size;
1303                 min_offs = end - base;
1304                 free = ext4_xattr_free_space(first, &min_offs, base,
1305                                              &total_blk);
1306                 if (free < new_extra_isize) {
1307                         if (!tried_min_extra_isize && s_min_extra_isize) {
1308                                 tried_min_extra_isize++;
1309                                 new_extra_isize = s_min_extra_isize;
1310                                 brelse(bh);
1311                                 goto retry;
1312                         }
1313                         error = -1;
1314                         goto cleanup;
1315                 }
1316         } else {
1317                 free = inode->i_sb->s_blocksize;
1318         }
1319
1320         while (new_extra_isize > 0) {
1321                 size_t offs, size, entry_size;
1322                 struct ext4_xattr_entry *small_entry = NULL;
1323                 struct ext4_xattr_info i = {
1324                         .value = NULL,
1325                         .value_len = 0,
1326                 };
1327                 unsigned int total_size;  /* EA entry size + value size */
1328                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1329                 unsigned int min_total_size = ~0U;
1330
1331                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1332                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1333                 if (!is || !bs) {
1334                         error = -ENOMEM;
1335                         goto cleanup;
1336                 }
1337
1338                 is->s.not_found = -ENODATA;
1339                 bs->s.not_found = -ENODATA;
1340                 is->iloc.bh = NULL;
1341                 bs->bh = NULL;
1342
1343                 last = IFIRST(header);
1344                 /* Find the entry best suited to be pushed into EA block */
1345                 entry = NULL;
1346                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1347                         total_size =
1348                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1349                                         EXT4_XATTR_LEN(last->e_name_len);
1350                         if (total_size <= free && total_size < min_total_size) {
1351                                 if (total_size < new_extra_isize) {
1352                                         small_entry = last;
1353                                 } else {
1354                                         entry = last;
1355                                         min_total_size = total_size;
1356                                 }
1357                         }
1358                 }
1359
1360                 if (entry == NULL) {
1361                         if (small_entry) {
1362                                 entry = small_entry;
1363                         } else {
1364                                 if (!tried_min_extra_isize &&
1365                                     s_min_extra_isize) {
1366                                         tried_min_extra_isize++;
1367                                         new_extra_isize = s_min_extra_isize;
1368                                         kfree(is); is = NULL;
1369                                         kfree(bs); bs = NULL;
1370                                         brelse(bh);
1371                                         goto retry;
1372                                 }
1373                                 error = -1;
1374                                 goto cleanup;
1375                         }
1376                 }
1377                 offs = le16_to_cpu(entry->e_value_offs);
1378                 size = le32_to_cpu(entry->e_value_size);
1379                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1380                 i.name_index = entry->e_name_index,
1381                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1382                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1383                 if (!buffer || !b_entry_name) {
1384                         error = -ENOMEM;
1385                         goto cleanup;
1386                 }
1387                 /* Save the entry name and the entry value */
1388                 memcpy(buffer, (void *)IFIRST(header) + offs,
1389                        EXT4_XATTR_SIZE(size));
1390                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1391                 b_entry_name[entry->e_name_len] = '\0';
1392                 i.name = b_entry_name;
1393
1394                 error = ext4_get_inode_loc(inode, &is->iloc);
1395                 if (error)
1396                         goto cleanup;
1397
1398                 error = ext4_xattr_ibody_find(inode, &i, is);
1399                 if (error)
1400                         goto cleanup;
1401
1402                 /* Remove the chosen entry from the inode */
1403                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1404                 if (error)
1405                         goto cleanup;
1406
1407                 entry = IFIRST(header);
1408                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1409                         shift_bytes = new_extra_isize;
1410                 else
1411                         shift_bytes = entry_size + size;
1412                 /* Adjust the offsets and shift the remaining entries ahead */
1413                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1414                         shift_bytes, (void *)raw_inode +
1415                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1416                         (void *)header, total_ino - entry_size,
1417                         inode->i_sb->s_blocksize);
1418
1419                 extra_isize += shift_bytes;
1420                 new_extra_isize -= shift_bytes;
1421                 EXT4_I(inode)->i_extra_isize = extra_isize;
1422
1423                 i.name = b_entry_name;
1424                 i.value = buffer;
1425                 i.value_len = size;
1426                 error = ext4_xattr_block_find(inode, &i, bs);
1427                 if (error)
1428                         goto cleanup;
1429
1430                 /* Add entry which was removed from the inode into the block */
1431                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1432                 if (error)
1433                         goto cleanup;
1434                 kfree(b_entry_name);
1435                 kfree(buffer);
1436                 b_entry_name = NULL;
1437                 buffer = NULL;
1438                 brelse(is->iloc.bh);
1439                 kfree(is);
1440                 kfree(bs);
1441         }
1442         brelse(bh);
1443         up_write(&EXT4_I(inode)->xattr_sem);
1444         return 0;
1445
1446 cleanup:
1447         kfree(b_entry_name);
1448         kfree(buffer);
1449         if (is)
1450                 brelse(is->iloc.bh);
1451         kfree(is);
1452         kfree(bs);
1453         brelse(bh);
1454         up_write(&EXT4_I(inode)->xattr_sem);
1455         return error;
1456 }
1457
1458
1459
1460 /*
1461  * ext4_xattr_delete_inode()
1462  *
1463  * Free extended attribute resources associated with this inode. This
1464  * is called immediately before an inode is freed. We have exclusive
1465  * access to the inode.
1466  */
1467 void
1468 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1469 {
1470         struct buffer_head *bh = NULL;
1471
1472         if (!EXT4_I(inode)->i_file_acl)
1473                 goto cleanup;
1474         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1475         if (!bh) {
1476                 EXT4_ERROR_INODE(inode, "block %llu read error",
1477                                  EXT4_I(inode)->i_file_acl);
1478                 goto cleanup;
1479         }
1480         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1481             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1482                 EXT4_ERROR_INODE(inode, "bad block %llu",
1483                                  EXT4_I(inode)->i_file_acl);
1484                 goto cleanup;
1485         }
1486         ext4_xattr_release_block(handle, inode, bh);
1487         EXT4_I(inode)->i_file_acl = 0;
1488
1489 cleanup:
1490         brelse(bh);
1491 }
1492
1493 /*
1494  * ext4_xattr_put_super()
1495  *
1496  * This is called when a file system is unmounted.
1497  */
1498 void
1499 ext4_xattr_put_super(struct super_block *sb)
1500 {
1501         mb_cache_shrink(sb->s_bdev);
1502 }
1503
1504 /*
1505  * ext4_xattr_cache_insert()
1506  *
1507  * Create a new entry in the extended attribute cache, and insert
1508  * it unless such an entry is already in the cache.
1509  *
1510  * Returns 0, or a negative error number on failure.
1511  */
1512 static void
1513 ext4_xattr_cache_insert(struct buffer_head *bh)
1514 {
1515         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1516         struct mb_cache_entry *ce;
1517         int error;
1518
1519         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1520         if (!ce) {
1521                 ea_bdebug(bh, "out of memory");
1522                 return;
1523         }
1524         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1525         if (error) {
1526                 mb_cache_entry_free(ce);
1527                 if (error == -EBUSY) {
1528                         ea_bdebug(bh, "already in cache");
1529                         error = 0;
1530                 }
1531         } else {
1532                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1533                 mb_cache_entry_release(ce);
1534         }
1535 }
1536
1537 /*
1538  * ext4_xattr_cmp()
1539  *
1540  * Compare two extended attribute blocks for equality.
1541  *
1542  * Returns 0 if the blocks are equal, 1 if they differ, and
1543  * a negative error number on errors.
1544  */
1545 static int
1546 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1547                struct ext4_xattr_header *header2)
1548 {
1549         struct ext4_xattr_entry *entry1, *entry2;
1550
1551         entry1 = ENTRY(header1+1);
1552         entry2 = ENTRY(header2+1);
1553         while (!IS_LAST_ENTRY(entry1)) {
1554                 if (IS_LAST_ENTRY(entry2))
1555                         return 1;
1556                 if (entry1->e_hash != entry2->e_hash ||
1557                     entry1->e_name_index != entry2->e_name_index ||
1558                     entry1->e_name_len != entry2->e_name_len ||
1559                     entry1->e_value_size != entry2->e_value_size ||
1560                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1561                         return 1;
1562                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1563                         return -EIO;
1564                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1565                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1566                            le32_to_cpu(entry1->e_value_size)))
1567                         return 1;
1568
1569                 entry1 = EXT4_XATTR_NEXT(entry1);
1570                 entry2 = EXT4_XATTR_NEXT(entry2);
1571         }
1572         if (!IS_LAST_ENTRY(entry2))
1573                 return 1;
1574         return 0;
1575 }
1576
1577 /*
1578  * ext4_xattr_cache_find()
1579  *
1580  * Find an identical extended attribute block.
1581  *
1582  * Returns a pointer to the block found, or NULL if such a block was
1583  * not found or an error occurred.
1584  */
1585 static struct buffer_head *
1586 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1587                       struct mb_cache_entry **pce)
1588 {
1589         __u32 hash = le32_to_cpu(header->h_hash);
1590         struct mb_cache_entry *ce;
1591
1592         if (!header->h_hash)
1593                 return NULL;  /* never share */
1594         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1595 again:
1596         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1597                                        hash);
1598         while (ce) {
1599                 struct buffer_head *bh;
1600
1601                 if (IS_ERR(ce)) {
1602                         if (PTR_ERR(ce) == -EAGAIN)
1603                                 goto again;
1604                         break;
1605                 }
1606                 bh = sb_bread(inode->i_sb, ce->e_block);
1607                 if (!bh) {
1608                         EXT4_ERROR_INODE(inode, "block %lu read error",
1609                                          (unsigned long) ce->e_block);
1610                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1611                                 EXT4_XATTR_REFCOUNT_MAX) {
1612                         ea_idebug(inode, "block %lu refcount %d>=%d",
1613                                   (unsigned long) ce->e_block,
1614                                   le32_to_cpu(BHDR(bh)->h_refcount),
1615                                           EXT4_XATTR_REFCOUNT_MAX);
1616                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1617                         *pce = ce;
1618                         return bh;
1619                 }
1620                 brelse(bh);
1621                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1622         }
1623         return NULL;
1624 }
1625
1626 #define NAME_HASH_SHIFT 5
1627 #define VALUE_HASH_SHIFT 16
1628
1629 /*
1630  * ext4_xattr_hash_entry()
1631  *
1632  * Compute the hash of an extended attribute.
1633  */
1634 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1635                                          struct ext4_xattr_entry *entry)
1636 {
1637         __u32 hash = 0;
1638         char *name = entry->e_name;
1639         int n;
1640
1641         for (n = 0; n < entry->e_name_len; n++) {
1642                 hash = (hash << NAME_HASH_SHIFT) ^
1643                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1644                        *name++;
1645         }
1646
1647         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1648                 __le32 *value = (__le32 *)((char *)header +
1649                         le16_to_cpu(entry->e_value_offs));
1650                 for (n = (le32_to_cpu(entry->e_value_size) +
1651                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1652                         hash = (hash << VALUE_HASH_SHIFT) ^
1653                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1654                                le32_to_cpu(*value++);
1655                 }
1656         }
1657         entry->e_hash = cpu_to_le32(hash);
1658 }
1659
1660 #undef NAME_HASH_SHIFT
1661 #undef VALUE_HASH_SHIFT
1662
1663 #define BLOCK_HASH_SHIFT 16
1664
1665 /*
1666  * ext4_xattr_rehash()
1667  *
1668  * Re-compute the extended attribute hash value after an entry has changed.
1669  */
1670 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1671                               struct ext4_xattr_entry *entry)
1672 {
1673         struct ext4_xattr_entry *here;
1674         __u32 hash = 0;
1675
1676         ext4_xattr_hash_entry(header, entry);
1677         here = ENTRY(header+1);
1678         while (!IS_LAST_ENTRY(here)) {
1679                 if (!here->e_hash) {
1680                         /* Block is not shared if an entry's hash value == 0 */
1681                         hash = 0;
1682                         break;
1683                 }
1684                 hash = (hash << BLOCK_HASH_SHIFT) ^
1685                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1686                        le32_to_cpu(here->e_hash);
1687                 here = EXT4_XATTR_NEXT(here);
1688         }
1689         header->h_hash = cpu_to_le32(hash);
1690 }
1691
1692 #undef BLOCK_HASH_SHIFT
1693
1694 int __init
1695 ext4_init_xattr(void)
1696 {
1697         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1698         if (!ext4_xattr_cache)
1699                 return -ENOMEM;
1700         return 0;
1701 }
1702
1703 void
1704 ext4_exit_xattr(void)
1705 {
1706         if (ext4_xattr_cache)
1707                 mb_cache_destroy(ext4_xattr_cache);
1708         ext4_xattr_cache = NULL;
1709 }