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]  = &posix_acl_access_xattr_handler,
  99         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_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         &posix_acl_access_xattr_handler,
 112         &posix_acl_default_xattr_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_metadata_csum(inode->i_sb) &&
 145             (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 146                 return 0;
 147         return 1;
 148 }
 149
 150 static void ext4_xattr_block_csum_set(struct inode *inode,
 151                                       sector_t block_nr,
 152                                       struct ext4_xattr_header *hdr)
 153 {
 154         if (!ext4_has_metadata_csum(inode->i_sb))
 155                 return;
 156
 157         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 158 }
 159
 160 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 161                                                 struct inode *inode,
 162                                                 struct buffer_head *bh)
 163 {
 164         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 165         return ext4_handle_dirty_metadata(handle, inode, bh);
 166 }
 167
 168 static inline const struct xattr_handler *
 169 ext4_xattr_handler(int name_index)
 170 {
 171         const struct xattr_handler *handler = NULL;
 172
 173         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 174                 handler = ext4_xattr_handler_map[name_index];
 175         return handler;
 176 }
 177
 178 /*
 179  * Inode operation listxattr()
 180  *
 181  * dentry->d_inode->i_mutex: don't care
 182  */
 183 ssize_t
 184 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 185 {
 186         return ext4_xattr_list(dentry, buffer, size);
 187 }
 188
 189 static int
 190 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
 191                        void *value_start)
 192 {
 193         struct ext4_xattr_entry *e = entry;
 194
 195         while (!IS_LAST_ENTRY(e)) {
 196                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 197                 if ((void *)next >= end)
 198                         return -EIO;
 199                 e = next;
 200         }
 201
 202         while (!IS_LAST_ENTRY(entry)) {
 203                 if (entry->e_value_size != 0 &&
 204                     (value_start + le16_to_cpu(entry->e_value_offs) <
 205                      (void *)e + sizeof(__u32) ||
 206                      value_start + le16_to_cpu(entry->e_value_offs) +
 207                     le32_to_cpu(entry->e_value_size) > end))
 208                         return -EIO;
 209                 entry = EXT4_XATTR_NEXT(entry);
 210         }
 211
 212         return 0;
 213 }
 214
 215 static inline int
 216 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 217 {
 218         int error;
 219
 220         if (buffer_verified(bh))
 221                 return 0;
 222
 223         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 224             BHDR(bh)->h_blocks != cpu_to_le32(1))
 225                 return -EIO;
 226         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 227                 return -EIO;
 228         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
 229                                        bh->b_data);
 230         if (!error)
 231                 set_buffer_verified(bh);
 232         return error;
 233 }
 234
 235 static inline int
 236 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 237 {
 238         size_t value_size = le32_to_cpu(entry->e_value_size);
 239
 240         if (entry->e_value_block != 0 || value_size > size ||
 241             le16_to_cpu(entry->e_value_offs) + value_size > size)
 242                 return -EIO;
 243         return 0;
 244 }
 245
 246 static int
 247 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 248                       const char *name, size_t size, int sorted)
 249 {
 250         struct ext4_xattr_entry *entry;
 251         size_t name_len;
 252         int cmp = 1;
 253
 254         if (name == NULL)
 255                 return -EINVAL;
 256         name_len = strlen(name);
 257         entry = *pentry;
 258         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 259                 cmp = name_index - entry->e_name_index;
 260                 if (!cmp)
 261                         cmp = name_len - entry->e_name_len;
 262                 if (!cmp)
 263                         cmp = memcmp(name, entry->e_name, name_len);
 264                 if (cmp <= 0 && (sorted || cmp == 0))
 265                         break;
 266         }
 267         *pentry = entry;
 268         if (!cmp && ext4_xattr_check_entry(entry, size))
 269                         return -EIO;
 270         return cmp ? -ENODATA : 0;
 271 }
 272
 273 static int
 274 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 275                      void *buffer, size_t buffer_size)
 276 {
 277         struct buffer_head *bh = NULL;
 278         struct ext4_xattr_entry *entry;
 279         size_t size;
 280         int error;
 281
 282         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 283                   name_index, name, buffer, (long)buffer_size);
 284
 285         error = -ENODATA;
 286         if (!EXT4_I(inode)->i_file_acl)
 287                 goto cleanup;
 288         ea_idebug(inode, "reading block %llu",
 289                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 290         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 291         if (!bh)
 292                 goto cleanup;
 293         ea_bdebug(bh, "b_count=%d, refcount=%d",
 294                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 295         if (ext4_xattr_check_block(inode, bh)) {
 296 bad_block:
 297                 EXT4_ERROR_INODE(inode, "bad block %llu",
 298                                  EXT4_I(inode)->i_file_acl);
 299                 error = -EIO;
 300                 goto cleanup;
 301         }
 302         ext4_xattr_cache_insert(bh);
 303         entry = BFIRST(bh);
 304         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 305         if (error == -EIO)
 306                 goto bad_block;
 307         if (error)
 308                 goto cleanup;
 309         size = le32_to_cpu(entry->e_value_size);
 310         if (buffer) {
 311                 error = -ERANGE;
 312                 if (size > buffer_size)
 313                         goto cleanup;
 314                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 315                        size);
 316         }
 317         error = size;
 318
 319 cleanup:
 320         brelse(bh);
 321         return error;
 322 }
 323
 324 int
 325 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 326                      void *buffer, size_t buffer_size)
 327 {
 328         struct ext4_xattr_ibody_header *header;
 329         struct ext4_xattr_entry *entry;
 330         struct ext4_inode *raw_inode;
 331         struct ext4_iloc iloc;
 332         size_t size;
 333         void *end;
 334         int error;
 335
 336         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 337                 return -ENODATA;
 338         error = ext4_get_inode_loc(inode, &iloc);
 339         if (error)
 340                 return error;
 341         raw_inode = ext4_raw_inode(&iloc);
 342         header = IHDR(inode, raw_inode);
 343         entry = IFIRST(header);
 344         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 345         error = ext4_xattr_check_names(entry, end, entry);
 346         if (error)
 347                 goto cleanup;
 348         error = ext4_xattr_find_entry(&entry, name_index, name,
 349                                       end - (void *)entry, 0);
 350         if (error)
 351                 goto cleanup;
 352         size = le32_to_cpu(entry->e_value_size);
 353         if (buffer) {
 354                 error = -ERANGE;
 355                 if (size > buffer_size)
 356                         goto cleanup;
 357                 memcpy(buffer, (void *)IFIRST(header) +
 358                        le16_to_cpu(entry->e_value_offs), size);
 359         }
 360         error = size;
 361
 362 cleanup:
 363         brelse(iloc.bh);
 364         return error;
 365 }
 366
 367 /*
 368  * ext4_xattr_get()
 369  *
 370  * Copy an extended attribute into the buffer
 371  * provided, or compute the buffer size required.
 372  * Buffer is NULL to compute the size of the buffer required.
 373  *
 374  * Returns a negative error number on failure, or the number of bytes
 375  * used / required on success.
 376  */
 377 int
 378 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 379                void *buffer, size_t buffer_size)
 380 {
 381         int error;
 382
 383         down_read(&EXT4_I(inode)->xattr_sem);
 384         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 385                                      buffer_size);
 386         if (error == -ENODATA)
 387                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 388                                              buffer_size);
 389         up_read(&EXT4_I(inode)->xattr_sem);
 390         return error;
 391 }
 392
 393 static int
 394 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 395                         char *buffer, size_t buffer_size)
 396 {
 397         size_t rest = buffer_size;
 398
 399         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 400                 const struct xattr_handler *handler =
 401                         ext4_xattr_handler(entry->e_name_index);
 402
 403                 if (handler) {
 404                         size_t size = handler->list(dentry, buffer, rest,
 405                                                     entry->e_name,
 406                                                     entry->e_name_len,
 407                                                     handler->flags);
 408                         if (buffer) {
 409                                 if (size > rest)
 410                                         return -ERANGE;
 411                                 buffer += size;
 412                         }
 413                         rest -= size;
 414                 }
 415         }
 416         return buffer_size - rest;
 417 }
 418
 419 static int
 420 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 421 {
 422         struct inode *inode = dentry->d_inode;
 423         struct buffer_head *bh = NULL;
 424         int error;
 425
 426         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 427                   buffer, (long)buffer_size);
 428
 429         error = 0;
 430         if (!EXT4_I(inode)->i_file_acl)
 431                 goto cleanup;
 432         ea_idebug(inode, "reading block %llu",
 433                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 434         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 435         error = -EIO;
 436         if (!bh)
 437                 goto cleanup;
 438         ea_bdebug(bh, "b_count=%d, refcount=%d",
 439                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 440         if (ext4_xattr_check_block(inode, bh)) {
 441                 EXT4_ERROR_INODE(inode, "bad block %llu",
 442                                  EXT4_I(inode)->i_file_acl);
 443                 error = -EIO;
 444                 goto cleanup;
 445         }
 446         ext4_xattr_cache_insert(bh);
 447         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 448
 449 cleanup:
 450         brelse(bh);
 451
 452         return error;
 453 }
 454
 455 static int
 456 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 457 {
 458         struct inode *inode = dentry->d_inode;
 459         struct ext4_xattr_ibody_header *header;
 460         struct ext4_inode *raw_inode;
 461         struct ext4_iloc iloc;
 462         void *end;
 463         int error;
 464
 465         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 466                 return 0;
 467         error = ext4_get_inode_loc(inode, &iloc);
 468         if (error)
 469                 return error;
 470         raw_inode = ext4_raw_inode(&iloc);
 471         header = IHDR(inode, raw_inode);
 472         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 473         error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
 474         if (error)
 475                 goto cleanup;
 476         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 477                                         buffer, buffer_size);
 478
 479 cleanup:
 480         brelse(iloc.bh);
 481         return error;
 482 }
 483
 484 /*
 485  * ext4_xattr_list()
 486  *
 487  * Copy a list of attribute names into the buffer
 488  * provided, or compute the buffer size required.
 489  * Buffer is NULL to compute the size of the buffer required.
 490  *
 491  * Returns a negative error number on failure, or the number of bytes
 492  * used / required on success.
 493  */
 494 static int
 495 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 496 {
 497         int ret, ret2;
 498
 499         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 500         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 501         if (ret < 0)
 502                 goto errout;
 503         if (buffer) {
 504                 buffer += ret;
 505                 buffer_size -= ret;
 506         }
 507         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 508         if (ret < 0)
 509                 goto errout;
 510         ret += ret2;
 511 errout:
 512         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 513         return ret;
 514 }
 515
 516 /*
 517  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 518  * not set, set it.
 519  */
 520 static void ext4_xattr_update_super_block(handle_t *handle,
 521                                           struct super_block *sb)
 522 {
 523         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 524                 return;
 525
 526         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 527                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 528                 ext4_handle_dirty_super(handle, sb);
 529         }
 530 }
 531
 532 /*
 533  * Release the xattr block BH: If the reference count is > 1, decrement it;
 534  * otherwise free the block.
 535  */
 536 static void
 537 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 538                          struct buffer_head *bh)
 539 {
 540         struct mb_cache_entry *ce = NULL;
 541         int error = 0;
 542
 543         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 544         error = ext4_journal_get_write_access(handle, bh);
 545         if (error)
 546                 goto out;
 547
 548         lock_buffer(bh);
 549         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 550                 ea_bdebug(bh, "refcount now=0; freeing");
 551                 if (ce)
 552                         mb_cache_entry_free(ce);
 553                 get_bh(bh);
 554                 unlock_buffer(bh);
 555                 ext4_free_blocks(handle, inode, bh, 0, 1,
 556                                  EXT4_FREE_BLOCKS_METADATA |
 557                                  EXT4_FREE_BLOCKS_FORGET);
 558         } else {
 559                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 560                 if (ce)
 561                         mb_cache_entry_release(ce);
 562                 /*
 563                  * Beware of this ugliness: Releasing of xattr block references
 564                  * from different inodes can race and so we have to protect
 565                  * from a race where someone else frees the block (and releases
 566                  * its journal_head) before we are done dirtying the buffer. In
 567                  * nojournal mode this race is harmless and we actually cannot
 568                  * call ext4_handle_dirty_xattr_block() with locked buffer as
 569                  * that function can call sync_dirty_buffer() so for that case
 570                  * we handle the dirtying after unlocking the buffer.
 571                  */
 572                 if (ext4_handle_valid(handle))
 573                         error = ext4_handle_dirty_xattr_block(handle, inode,
 574                                                               bh);
 575                 unlock_buffer(bh);
 576                 if (!ext4_handle_valid(handle))
 577                         error = ext4_handle_dirty_xattr_block(handle, inode,
 578                                                               bh);
 579                 if (IS_SYNC(inode))
 580                         ext4_handle_sync(handle);
 581                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 582                 ea_bdebug(bh, "refcount now=%d; releasing",
 583                           le32_to_cpu(BHDR(bh)->h_refcount));
 584         }
 585 out:
 586         ext4_std_error(inode->i_sb, error);
 587         return;
 588 }
 589
 590 /*
 591  * Find the available free space for EAs. This also returns the total number of
 592  * bytes used by EA entries.
 593  */
 594 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 595                                     size_t *min_offs, void *base, int *total)
 596 {
 597         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 598                 *total += EXT4_XATTR_LEN(last->e_name_len);
 599                 if (!last->e_value_block && last->e_value_size) {
 600                         size_t offs = le16_to_cpu(last->e_value_offs);
 601                         if (offs < *min_offs)
 602                                 *min_offs = offs;
 603                 }
 604         }
 605         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 606 }
 607
 608 static int
 609 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 610 {
 611         struct ext4_xattr_entry *last;
 612         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 613
 614         /* Compute min_offs and last. */
 615         last = s->first;
 616         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 617                 if (!last->e_value_block && last->e_value_size) {
 618                         size_t offs = le16_to_cpu(last->e_value_offs);
 619                         if (offs < min_offs)
 620                                 min_offs = offs;
 621                 }
 622         }
 623         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 624         if (!s->not_found) {
 625                 if (!s->here->e_value_block && s->here->e_value_size) {
 626                         size_t size = le32_to_cpu(s->here->e_value_size);
 627                         free += EXT4_XATTR_SIZE(size);
 628                 }
 629                 free += EXT4_XATTR_LEN(name_len);
 630         }
 631         if (i->value) {
 632                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 633                     free < EXT4_XATTR_LEN(name_len) +
 634                            EXT4_XATTR_SIZE(i->value_len))
 635                         return -ENOSPC;
 636         }
 637
 638         if (i->value && s->not_found) {
 639                 /* Insert the new name. */
 640                 size_t size = EXT4_XATTR_LEN(name_len);
 641                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 642                 memmove((void *)s->here + size, s->here, rest);
 643                 memset(s->here, 0, size);
 644                 s->here->e_name_index = i->name_index;
 645                 s->here->e_name_len = name_len;
 646                 memcpy(s->here->e_name, i->name, name_len);
 647         } else {
 648                 if (!s->here->e_value_block && s->here->e_value_size) {
 649                         void *first_val = s->base + min_offs;
 650                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 651                         void *val = s->base + offs;
 652                         size_t size = EXT4_XATTR_SIZE(
 653                                 le32_to_cpu(s->here->e_value_size));
 654
 655                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 656                                 /* The old and the new value have the same
 657                                    size. Just replace. */
 658                                 s->here->e_value_size =
 659                                         cpu_to_le32(i->value_len);
 660                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 661                                         memset(val, 0, size);
 662                                 } else {
 663                                         /* Clear pad bytes first. */
 664                                         memset(val + size - EXT4_XATTR_PAD, 0,
 665                                                EXT4_XATTR_PAD);
 666                                         memcpy(val, i->value, i->value_len);
 667                                 }
 668                                 return 0;
 669                         }
 670
 671                         /* Remove the old value. */
 672                         memmove(first_val + size, first_val, val - first_val);
 673                         memset(first_val, 0, size);
 674                         s->here->e_value_size = 0;
 675                         s->here->e_value_offs = 0;
 676                         min_offs += size;
 677
 678                         /* Adjust all value offsets. */
 679                         last = s->first;
 680                         while (!IS_LAST_ENTRY(last)) {
 681                                 size_t o = le16_to_cpu(last->e_value_offs);
 682                                 if (!last->e_value_block &&
 683                                     last->e_value_size && o < offs)
 684                                         last->e_value_offs =
 685                                                 cpu_to_le16(o + size);
 686                                 last = EXT4_XATTR_NEXT(last);
 687                         }
 688                 }
 689                 if (!i->value) {
 690                         /* Remove the old name. */
 691                         size_t size = EXT4_XATTR_LEN(name_len);
 692                         last = ENTRY((void *)last - size);
 693                         memmove(s->here, (void *)s->here + size,
 694                                 (void *)last - (void *)s->here + sizeof(__u32));
 695                         memset(last, 0, size);
 696                 }
 697         }
 698
 699         if (i->value) {
 700                 /* Insert the new value. */
 701                 s->here->e_value_size = cpu_to_le32(i->value_len);
 702                 if (i->value_len) {
 703                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 704                         void *val = s->base + min_offs - size;
 705                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 706                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 707                                 memset(val, 0, size);
 708                         } else {
 709                                 /* Clear the pad bytes first. */
 710                                 memset(val + size - EXT4_XATTR_PAD, 0,
 711                                        EXT4_XATTR_PAD);
 712                                 memcpy(val, i->value, i->value_len);
 713                         }
 714                 }
 715         }
 716         return 0;
 717 }
 718
 719 struct ext4_xattr_block_find {
 720         struct ext4_xattr_search s;
 721         struct buffer_head *bh;
 722 };
 723
 724 static int
 725 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 726                       struct ext4_xattr_block_find *bs)
 727 {
 728         struct super_block *sb = inode->i_sb;
 729         int error;
 730
 731         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 732                   i->name_index, i->name, i->value, (long)i->value_len);
 733
 734         if (EXT4_I(inode)->i_file_acl) {
 735                 /* The inode already has an extended attribute block. */
 736                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 737                 error = -EIO;
 738                 if (!bs->bh)
 739                         goto cleanup;
 740                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 741                         atomic_read(&(bs->bh->b_count)),
 742                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 743                 if (ext4_xattr_check_block(inode, bs->bh)) {
 744                         EXT4_ERROR_INODE(inode, "bad block %llu",
 745                                          EXT4_I(inode)->i_file_acl);
 746                         error = -EIO;
 747                         goto cleanup;
 748                 }
 749                 /* Find the named attribute. */
 750                 bs->s.base = BHDR(bs->bh);
 751                 bs->s.first = BFIRST(bs->bh);
 752                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 753                 bs->s.here = bs->s.first;
 754                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 755                                               i->name, bs->bh->b_size, 1);
 756                 if (error && error != -ENODATA)
 757                         goto cleanup;
 758                 bs->s.not_found = error;
 759         }
 760         error = 0;
 761
 762 cleanup:
 763         return error;
 764 }
 765
 766 static int
 767 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 768                      struct ext4_xattr_info *i,
 769                      struct ext4_xattr_block_find *bs)
 770 {
 771         struct super_block *sb = inode->i_sb;
 772         struct buffer_head *new_bh = NULL;
 773         struct ext4_xattr_search *s = &bs->s;
 774         struct mb_cache_entry *ce = NULL;
 775         int error = 0;
 776
 777 #define header(x) ((struct ext4_xattr_header *)(x))
 778
 779         if (i->value && i->value_len > sb->s_blocksize)
 780                 return -ENOSPC;
 781         if (s->base) {
 782                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 783                                         bs->bh->b_blocknr);
 784                 error = ext4_journal_get_write_access(handle, bs->bh);
 785                 if (error)
 786                         goto cleanup;
 787                 lock_buffer(bs->bh);
 788
 789                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 790                         if (ce) {
 791                                 mb_cache_entry_free(ce);
 792                                 ce = NULL;
 793                         }
 794                         ea_bdebug(bs->bh, "modifying in-place");
 795                         error = ext4_xattr_set_entry(i, s);
 796                         if (!error) {
 797                                 if (!IS_LAST_ENTRY(s->first))
 798                                         ext4_xattr_rehash(header(s->base),
 799                                                           s->here);
 800                                 ext4_xattr_cache_insert(bs->bh);
 801                         }
 802                         unlock_buffer(bs->bh);
 803                         if (error == -EIO)
 804                                 goto bad_block;
 805                         if (!error)
 806                                 error = ext4_handle_dirty_xattr_block(handle,
 807                                                                       inode,
 808                                                                       bs->bh);
 809                         if (error)
 810                                 goto cleanup;
 811                         goto inserted;
 812                 } else {
 813                         int offset = (char *)s->here - bs->bh->b_data;
 814
 815                         unlock_buffer(bs->bh);
 816                         if (ce) {
 817                                 mb_cache_entry_release(ce);
 818                                 ce = NULL;
 819                         }
 820                         ea_bdebug(bs->bh, "cloning");
 821                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 822                         error = -ENOMEM;
 823                         if (s->base == NULL)
 824                                 goto cleanup;
 825                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 826                         s->first = ENTRY(header(s->base)+1);
 827                         header(s->base)->h_refcount = cpu_to_le32(1);
 828                         s->here = ENTRY(s->base + offset);
 829                         s->end = s->base + bs->bh->b_size;
 830                 }
 831         } else {
 832                 /* Allocate a buffer where we construct the new block. */
 833                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 834                 /* assert(header == s->base) */
 835                 error = -ENOMEM;
 836                 if (s->base == NULL)
 837                         goto cleanup;
 838                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 839                 header(s->base)->h_blocks = cpu_to_le32(1);
 840                 header(s->base)->h_refcount = cpu_to_le32(1);
 841                 s->first = ENTRY(header(s->base)+1);
 842                 s->here = ENTRY(header(s->base)+1);
 843                 s->end = s->base + sb->s_blocksize;
 844         }
 845
 846         error = ext4_xattr_set_entry(i, s);
 847         if (error == -EIO)
 848                 goto bad_block;
 849         if (error)
 850                 goto cleanup;
 851         if (!IS_LAST_ENTRY(s->first))
 852                 ext4_xattr_rehash(header(s->base), s->here);
 853
 854 inserted:
 855         if (!IS_LAST_ENTRY(s->first)) {
 856                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 857                 if (new_bh) {
 858                         /* We found an identical block in the cache. */
 859                         if (new_bh == bs->bh)
 860                                 ea_bdebug(new_bh, "keeping");
 861                         else {
 862                                 /* The old block is released after updating
 863                                    the inode. */
 864                                 error = dquot_alloc_block(inode,
 865                                                 EXT4_C2B(EXT4_SB(sb), 1));
 866                                 if (error)
 867                                         goto cleanup;
 868                                 error = ext4_journal_get_write_access(handle,
 869                                                                       new_bh);
 870                                 if (error)
 871                                         goto cleanup_dquot;
 872                                 lock_buffer(new_bh);
 873                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 874                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 875                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 876                                 unlock_buffer(new_bh);
 877                                 error = ext4_handle_dirty_xattr_block(handle,
 878                                                                       inode,
 879                                                                       new_bh);
 880                                 if (error)
 881                                         goto cleanup_dquot;
 882                         }
 883                         mb_cache_entry_release(ce);
 884                         ce = NULL;
 885                 } else if (bs->bh && s->base == bs->bh->b_data) {
 886                         /* We were modifying this block in-place. */
 887                         ea_bdebug(bs->bh, "keeping this block");
 888                         new_bh = bs->bh;
 889                         get_bh(new_bh);
 890                 } else {
 891                         /* We need to allocate a new block */
 892                         ext4_fsblk_t goal, block;
 893
 894                         goal = ext4_group_first_block_no(sb,
 895                                                 EXT4_I(inode)->i_block_group);
 896
 897                         /* non-extent files can't have physical blocks past 2^32 */
 898                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 899                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 900
 901                         /*
 902                          * take i_data_sem because we will test
 903                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 904                          */
 905                         down_read((&EXT4_I(inode)->i_data_sem));
 906                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 907                                                      NULL, &error);
 908                         up_read((&EXT4_I(inode)->i_data_sem));
 909                         if (error)
 910                                 goto cleanup;
 911
 912                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 913                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 914
 915                         ea_idebug(inode, "creating block %llu",
 916                                   (unsigned long long)block);
 917
 918                         new_bh = sb_getblk(sb, block);
 919                         if (unlikely(!new_bh)) {
 920                                 error = -ENOMEM;
 921 getblk_failed:
 922                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 923                                                  EXT4_FREE_BLOCKS_METADATA);
 924                                 goto cleanup;
 925                         }
 926                         lock_buffer(new_bh);
 927                         error = ext4_journal_get_create_access(handle, new_bh);
 928                         if (error) {
 929                                 unlock_buffer(new_bh);
 930                                 error = -EIO;
 931                                 goto getblk_failed;
 932                         }
 933                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 934                         set_buffer_uptodate(new_bh);
 935                         unlock_buffer(new_bh);
 936                         ext4_xattr_cache_insert(new_bh);
 937                         error = ext4_handle_dirty_xattr_block(handle,
 938                                                               inode, new_bh);
 939                         if (error)
 940                                 goto cleanup;
 941                 }
 942         }
 943
 944         /* Update the inode. */
 945         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 946
 947         /* Drop the previous xattr block. */
 948         if (bs->bh && bs->bh != new_bh)
 949                 ext4_xattr_release_block(handle, inode, bs->bh);
 950         error = 0;
 951
 952 cleanup:
 953         if (ce)
 954                 mb_cache_entry_release(ce);
 955         brelse(new_bh);
 956         if (!(bs->bh && s->base == bs->bh->b_data))
 957                 kfree(s->base);
 958
 959         return error;
 960
 961 cleanup_dquot:
 962         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 963         goto cleanup;
 964
 965 bad_block:
 966         EXT4_ERROR_INODE(inode, "bad block %llu",
 967                          EXT4_I(inode)->i_file_acl);
 968         goto cleanup;
 969
 970 #undef header
 971 }
 972
 973 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 974                           struct ext4_xattr_ibody_find *is)
 975 {
 976         struct ext4_xattr_ibody_header *header;
 977         struct ext4_inode *raw_inode;
 978         int error;
 979
 980         if (EXT4_I(inode)->i_extra_isize == 0)
 981                 return 0;
 982         raw_inode = ext4_raw_inode(&is->iloc);
 983         header = IHDR(inode, raw_inode);
 984         is->s.base = is->s.first = IFIRST(header);
 985         is->s.here = is->s.first;
 986         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 987         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 988                 error = ext4_xattr_check_names(IFIRST(header), is->s.end,
 989                                                IFIRST(header));
 990                 if (error)
 991                         return error;
 992                 /* Find the named attribute. */
 993                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 994                                               i->name, is->s.end -
 995                                               (void *)is->s.base, 0);
 996                 if (error && error != -ENODATA)
 997                         return error;
 998                 is->s.not_found = error;
 999         }
1000         return 0;
1001 }
1002
1003 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1004                                 struct ext4_xattr_info *i,
1005                                 struct ext4_xattr_ibody_find *is)
1006 {
1007         struct ext4_xattr_ibody_header *header;
1008         struct ext4_xattr_search *s = &is->s;
1009         int error;
1010
1011         if (EXT4_I(inode)->i_extra_isize == 0)
1012                 return -ENOSPC;
1013         error = ext4_xattr_set_entry(i, s);
1014         if (error) {
1015                 if (error == -ENOSPC &&
1016                     ext4_has_inline_data(inode)) {
1017                         error = ext4_try_to_evict_inline_data(handle, inode,
1018                                         EXT4_XATTR_LEN(strlen(i->name) +
1019                                         EXT4_XATTR_SIZE(i->value_len)));
1020                         if (error)
1021                                 return error;
1022                         error = ext4_xattr_ibody_find(inode, i, is);
1023                         if (error)
1024                                 return error;
1025                         error = ext4_xattr_set_entry(i, s);
1026                 }
1027                 if (error)
1028                         return error;
1029         }
1030         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1031         if (!IS_LAST_ENTRY(s->first)) {
1032                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1033                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1034         } else {
1035                 header->h_magic = cpu_to_le32(0);
1036                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1037         }
1038         return 0;
1039 }
1040
1041 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1042                                 struct ext4_xattr_info *i,
1043                                 struct ext4_xattr_ibody_find *is)
1044 {
1045         struct ext4_xattr_ibody_header *header;
1046         struct ext4_xattr_search *s = &is->s;
1047         int error;
1048
1049         if (EXT4_I(inode)->i_extra_isize == 0)
1050                 return -ENOSPC;
1051         error = ext4_xattr_set_entry(i, s);
1052         if (error)
1053                 return error;
1054         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1055         if (!IS_LAST_ENTRY(s->first)) {
1056                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1057                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1058         } else {
1059                 header->h_magic = cpu_to_le32(0);
1060                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1061         }
1062         return 0;
1063 }
1064
1065 /*
1066  * ext4_xattr_set_handle()
1067  *
1068  * Create, replace or remove an extended attribute for this inode.  Value
1069  * is NULL to remove an existing extended attribute, and non-NULL to
1070  * either replace an existing extended attribute, or create a new extended
1071  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1072  * specify that an extended attribute must exist and must not exist
1073  * previous to the call, respectively.
1074  *
1075  * Returns 0, or a negative error number on failure.
1076  */
1077 int
1078 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1079                       const char *name, const void *value, size_t value_len,
1080                       int flags)
1081 {
1082         struct ext4_xattr_info i = {
1083                 .name_index = name_index,
1084                 .name = name,
1085                 .value = value,
1086                 .value_len = value_len,
1087
1088         };
1089         struct ext4_xattr_ibody_find is = {
1090                 .s = { .not_found = -ENODATA, },
1091         };
1092         struct ext4_xattr_block_find bs = {
1093                 .s = { .not_found = -ENODATA, },
1094         };
1095         unsigned long no_expand;
1096         int error;
1097
1098         if (!name)
1099                 return -EINVAL;
1100         if (strlen(name) > 255)
1101                 return -ERANGE;
1102         down_write(&EXT4_I(inode)->xattr_sem);
1103         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1104         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1105
1106         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1107         if (error)
1108                 goto cleanup;
1109
1110         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1111                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1112                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1113                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1114         }
1115
1116         error = ext4_xattr_ibody_find(inode, &i, &is);
1117         if (error)
1118                 goto cleanup;
1119         if (is.s.not_found)
1120                 error = ext4_xattr_block_find(inode, &i, &bs);
1121         if (error)
1122                 goto cleanup;
1123         if (is.s.not_found && bs.s.not_found) {
1124                 error = -ENODATA;
1125                 if (flags & XATTR_REPLACE)
1126                         goto cleanup;
1127                 error = 0;
1128                 if (!value)
1129                         goto cleanup;
1130         } else {
1131                 error = -EEXIST;
1132                 if (flags & XATTR_CREATE)
1133                         goto cleanup;
1134         }
1135         if (!value) {
1136                 if (!is.s.not_found)
1137                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1138                 else if (!bs.s.not_found)
1139                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1140         } else {
1141                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1142                 if (!error && !bs.s.not_found) {
1143                         i.value = NULL;
1144                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1145                 } else if (error == -ENOSPC) {
1146                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1147                                 error = ext4_xattr_block_find(inode, &i, &bs);
1148                                 if (error)
1149                                         goto cleanup;
1150                         }
1151                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1152                         if (error)
1153                                 goto cleanup;
1154                         if (!is.s.not_found) {
1155                                 i.value = NULL;
1156                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1157                                                              &is);
1158                         }
1159                 }
1160         }
1161         if (!error) {
1162                 ext4_xattr_update_super_block(handle, inode->i_sb);
1163                 inode->i_ctime = ext4_current_time(inode);
1164                 if (!value)
1165                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1166                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1167                 /*
1168                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1169                  * error != 0.
1170                  */
1171                 is.iloc.bh = NULL;
1172                 if (IS_SYNC(inode))
1173                         ext4_handle_sync(handle);
1174         }
1175
1176 cleanup:
1177         brelse(is.iloc.bh);
1178         brelse(bs.bh);
1179         if (no_expand == 0)
1180                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1181         up_write(&EXT4_I(inode)->xattr_sem);
1182         return error;
1183 }
1184
1185 /*
1186  * ext4_xattr_set()
1187  *
1188  * Like ext4_xattr_set_handle, but start from an inode. This extended
1189  * attribute modification is a filesystem transaction by itself.
1190  *
1191  * Returns 0, or a negative error number on failure.
1192  */
1193 int
1194 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1195                const void *value, size_t value_len, int flags)
1196 {
1197         handle_t *handle;
1198         int error, retries = 0;
1199         int credits = ext4_jbd2_credits_xattr(inode);
1200
1201 retry:
1202         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1203         if (IS_ERR(handle)) {
1204                 error = PTR_ERR(handle);
1205         } else {
1206                 int error2;
1207
1208                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1209                                               value, value_len, flags);
1210                 error2 = ext4_journal_stop(handle);
1211                 if (error == -ENOSPC &&
1212                     ext4_should_retry_alloc(inode->i_sb, &retries))
1213                         goto retry;
1214                 if (error == 0)
1215                         error = error2;
1216         }
1217
1218         return error;
1219 }
1220
1221 /*
1222  * Shift the EA entries in the inode to create space for the increased
1223  * i_extra_isize.
1224  */
1225 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1226                                      int value_offs_shift, void *to,
1227                                      void *from, size_t n, int blocksize)
1228 {
1229         struct ext4_xattr_entry *last = entry;
1230         int new_offs;
1231
1232         /* Adjust the value offsets of the entries */
1233         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1234                 if (!last->e_value_block && last->e_value_size) {
1235                         new_offs = le16_to_cpu(last->e_value_offs) +
1236                                                         value_offs_shift;
1237                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1238                                  > blocksize);
1239                         last->e_value_offs = cpu_to_le16(new_offs);
1240                 }
1241         }
1242         /* Shift the entries by n bytes */
1243         memmove(to, from, n);
1244 }
1245
1246 /*
1247  * Expand an inode by new_extra_isize bytes when EAs are present.
1248  * Returns 0 on success or negative error number on failure.
1249  */
1250 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1251                                struct ext4_inode *raw_inode, handle_t *handle)
1252 {
1253         struct ext4_xattr_ibody_header *header;
1254         struct ext4_xattr_entry *entry, *last, *first;
1255         struct buffer_head *bh = NULL;
1256         struct ext4_xattr_ibody_find *is = NULL;
1257         struct ext4_xattr_block_find *bs = NULL;
1258         char *buffer = NULL, *b_entry_name = NULL;
1259         size_t min_offs, free;
1260         int total_ino, total_blk;
1261         void *base, *start, *end;
1262         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1263         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1264
1265         down_write(&EXT4_I(inode)->xattr_sem);
1266 retry:
1267         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1268                 up_write(&EXT4_I(inode)->xattr_sem);
1269                 return 0;
1270         }
1271
1272         header = IHDR(inode, raw_inode);
1273         entry = IFIRST(header);
1274
1275         /*
1276          * Check if enough free space is available in the inode to shift the
1277          * entries ahead by new_extra_isize.
1278          */
1279
1280         base = start = entry;
1281         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1282         min_offs = end - base;
1283         last = entry;
1284         total_ino = sizeof(struct ext4_xattr_ibody_header);
1285
1286         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1287         if (free >= new_extra_isize) {
1288                 entry = IFIRST(header);
1289                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1290                                 - new_extra_isize, (void *)raw_inode +
1291                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1292                                 (void *)header, total_ino,
1293                                 inode->i_sb->s_blocksize);
1294                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1295                 error = 0;
1296                 goto cleanup;
1297         }
1298
1299         /*
1300          * Enough free space isn't available in the inode, check if
1301          * EA block can hold new_extra_isize bytes.
1302          */
1303         if (EXT4_I(inode)->i_file_acl) {
1304                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1305                 error = -EIO;
1306                 if (!bh)
1307                         goto cleanup;
1308                 if (ext4_xattr_check_block(inode, bh)) {
1309                         EXT4_ERROR_INODE(inode, "bad block %llu",
1310                                          EXT4_I(inode)->i_file_acl);
1311                         error = -EIO;
1312                         goto cleanup;
1313                 }
1314                 base = BHDR(bh);
1315                 first = BFIRST(bh);
1316                 end = bh->b_data + bh->b_size;
1317                 min_offs = end - base;
1318                 free = ext4_xattr_free_space(first, &min_offs, base,
1319                                              &total_blk);
1320                 if (free < new_extra_isize) {
1321                         if (!tried_min_extra_isize && s_min_extra_isize) {
1322                                 tried_min_extra_isize++;
1323                                 new_extra_isize = s_min_extra_isize;
1324                                 brelse(bh);
1325                                 goto retry;
1326                         }
1327                         error = -1;
1328                         goto cleanup;
1329                 }
1330         } else {
1331                 free = inode->i_sb->s_blocksize;
1332         }
1333
1334         while (new_extra_isize > 0) {
1335                 size_t offs, size, entry_size;
1336                 struct ext4_xattr_entry *small_entry = NULL;
1337                 struct ext4_xattr_info i = {
1338                         .value = NULL,
1339                         .value_len = 0,
1340                 };
1341                 unsigned int total_size;  /* EA entry size + value size */
1342                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1343                 unsigned int min_total_size = ~0U;
1344
1345                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1346                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1347                 if (!is || !bs) {
1348                         error = -ENOMEM;
1349                         goto cleanup;
1350                 }
1351
1352                 is->s.not_found = -ENODATA;
1353                 bs->s.not_found = -ENODATA;
1354                 is->iloc.bh = NULL;
1355                 bs->bh = NULL;
1356
1357                 last = IFIRST(header);
1358                 /* Find the entry best suited to be pushed into EA block */
1359                 entry = NULL;
1360                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1361                         total_size =
1362                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1363                                         EXT4_XATTR_LEN(last->e_name_len);
1364                         if (total_size <= free && total_size < min_total_size) {
1365                                 if (total_size < new_extra_isize) {
1366                                         small_entry = last;
1367                                 } else {
1368                                         entry = last;
1369                                         min_total_size = total_size;
1370                                 }
1371                         }
1372                 }
1373
1374                 if (entry == NULL) {
1375                         if (small_entry) {
1376                                 entry = small_entry;
1377                         } else {
1378                                 if (!tried_min_extra_isize &&
1379                                     s_min_extra_isize) {
1380                                         tried_min_extra_isize++;
1381                                         new_extra_isize = s_min_extra_isize;
1382                                         kfree(is); is = NULL;
1383                                         kfree(bs); bs = NULL;
1384                                         brelse(bh);
1385                                         goto retry;
1386                                 }
1387                                 error = -1;
1388                                 goto cleanup;
1389                         }
1390                 }
1391                 offs = le16_to_cpu(entry->e_value_offs);
1392                 size = le32_to_cpu(entry->e_value_size);
1393                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1394                 i.name_index = entry->e_name_index,
1395                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1396                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1397                 if (!buffer || !b_entry_name) {
1398                         error = -ENOMEM;
1399                         goto cleanup;
1400                 }
1401                 /* Save the entry name and the entry value */
1402                 memcpy(buffer, (void *)IFIRST(header) + offs,
1403                        EXT4_XATTR_SIZE(size));
1404                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1405                 b_entry_name[entry->e_name_len] = '\0';
1406                 i.name = b_entry_name;
1407
1408                 error = ext4_get_inode_loc(inode, &is->iloc);
1409                 if (error)
1410                         goto cleanup;
1411
1412                 error = ext4_xattr_ibody_find(inode, &i, is);
1413                 if (error)
1414                         goto cleanup;
1415
1416                 /* Remove the chosen entry from the inode */
1417                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1418                 if (error)
1419                         goto cleanup;
1420
1421                 entry = IFIRST(header);
1422                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1423                         shift_bytes = new_extra_isize;
1424                 else
1425                         shift_bytes = entry_size + size;
1426                 /* Adjust the offsets and shift the remaining entries ahead */
1427                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1428                         shift_bytes, (void *)raw_inode +
1429                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1430                         (void *)header, total_ino - entry_size,
1431                         inode->i_sb->s_blocksize);
1432
1433                 extra_isize += shift_bytes;
1434                 new_extra_isize -= shift_bytes;
1435                 EXT4_I(inode)->i_extra_isize = extra_isize;
1436
1437                 i.name = b_entry_name;
1438                 i.value = buffer;
1439                 i.value_len = size;
1440                 error = ext4_xattr_block_find(inode, &i, bs);
1441                 if (error)
1442                         goto cleanup;
1443
1444                 /* Add entry which was removed from the inode into the block */
1445                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1446                 if (error)
1447                         goto cleanup;
1448                 kfree(b_entry_name);
1449                 kfree(buffer);
1450                 b_entry_name = NULL;
1451                 buffer = NULL;
1452                 brelse(is->iloc.bh);
1453                 kfree(is);
1454                 kfree(bs);
1455         }
1456         brelse(bh);
1457         up_write(&EXT4_I(inode)->xattr_sem);
1458         return 0;
1459
1460 cleanup:
1461         kfree(b_entry_name);
1462         kfree(buffer);
1463         if (is)
1464                 brelse(is->iloc.bh);
1465         kfree(is);
1466         kfree(bs);
1467         brelse(bh);
1468         up_write(&EXT4_I(inode)->xattr_sem);
1469         return error;
1470 }
1471
1472
1473
1474 /*
1475  * ext4_xattr_delete_inode()
1476  *
1477  * Free extended attribute resources associated with this inode. This
1478  * is called immediately before an inode is freed. We have exclusive
1479  * access to the inode.
1480  */
1481 void
1482 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1483 {
1484         struct buffer_head *bh = NULL;
1485
1486         if (!EXT4_I(inode)->i_file_acl)
1487                 goto cleanup;
1488         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1489         if (!bh) {
1490                 EXT4_ERROR_INODE(inode, "block %llu read error",
1491                                  EXT4_I(inode)->i_file_acl);
1492                 goto cleanup;
1493         }
1494         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1495             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1496                 EXT4_ERROR_INODE(inode, "bad block %llu",
1497                                  EXT4_I(inode)->i_file_acl);
1498                 goto cleanup;
1499         }
1500         ext4_xattr_release_block(handle, inode, bh);
1501         EXT4_I(inode)->i_file_acl = 0;
1502
1503 cleanup:
1504         brelse(bh);
1505 }
1506
1507 /*
1508  * ext4_xattr_put_super()
1509  *
1510  * This is called when a file system is unmounted.
1511  */
1512 void
1513 ext4_xattr_put_super(struct super_block *sb)
1514 {
1515         mb_cache_shrink(sb->s_bdev);
1516 }
1517
1518 /*
1519  * ext4_xattr_cache_insert()
1520  *
1521  * Create a new entry in the extended attribute cache, and insert
1522  * it unless such an entry is already in the cache.
1523  *
1524  * Returns 0, or a negative error number on failure.
1525  */
1526 static void
1527 ext4_xattr_cache_insert(struct buffer_head *bh)
1528 {
1529         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1530         struct mb_cache_entry *ce;
1531         int error;
1532
1533         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1534         if (!ce) {
1535                 ea_bdebug(bh, "out of memory");
1536                 return;
1537         }
1538         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1539         if (error) {
1540                 mb_cache_entry_free(ce);
1541                 if (error == -EBUSY) {
1542                         ea_bdebug(bh, "already in cache");
1543                         error = 0;
1544                 }
1545         } else {
1546                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1547                 mb_cache_entry_release(ce);
1548         }
1549 }
1550
1551 /*
1552  * ext4_xattr_cmp()
1553  *
1554  * Compare two extended attribute blocks for equality.
1555  *
1556  * Returns 0 if the blocks are equal, 1 if they differ, and
1557  * a negative error number on errors.
1558  */
1559 static int
1560 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1561                struct ext4_xattr_header *header2)
1562 {
1563         struct ext4_xattr_entry *entry1, *entry2;
1564
1565         entry1 = ENTRY(header1+1);
1566         entry2 = ENTRY(header2+1);
1567         while (!IS_LAST_ENTRY(entry1)) {
1568                 if (IS_LAST_ENTRY(entry2))
1569                         return 1;
1570                 if (entry1->e_hash != entry2->e_hash ||
1571                     entry1->e_name_index != entry2->e_name_index ||
1572                     entry1->e_name_len != entry2->e_name_len ||
1573                     entry1->e_value_size != entry2->e_value_size ||
1574                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1575                         return 1;
1576                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1577                         return -EIO;
1578                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1579                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1580                            le32_to_cpu(entry1->e_value_size)))
1581                         return 1;
1582
1583                 entry1 = EXT4_XATTR_NEXT(entry1);
1584                 entry2 = EXT4_XATTR_NEXT(entry2);
1585         }
1586         if (!IS_LAST_ENTRY(entry2))
1587                 return 1;
1588         return 0;
1589 }
1590
1591 /*
1592  * ext4_xattr_cache_find()
1593  *
1594  * Find an identical extended attribute block.
1595  *
1596  * Returns a pointer to the block found, or NULL if such a block was
1597  * not found or an error occurred.
1598  */
1599 static struct buffer_head *
1600 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1601                       struct mb_cache_entry **pce)
1602 {
1603         __u32 hash = le32_to_cpu(header->h_hash);
1604         struct mb_cache_entry *ce;
1605
1606         if (!header->h_hash)
1607                 return NULL;  /* never share */
1608         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1609 again:
1610         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1611                                        hash);
1612         while (ce) {
1613                 struct buffer_head *bh;
1614
1615                 if (IS_ERR(ce)) {
1616                         if (PTR_ERR(ce) == -EAGAIN)
1617                                 goto again;
1618                         break;
1619                 }
1620                 bh = sb_bread(inode->i_sb, ce->e_block);
1621                 if (!bh) {
1622                         EXT4_ERROR_INODE(inode, "block %lu read error",
1623                                          (unsigned long) ce->e_block);
1624                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1625                                 EXT4_XATTR_REFCOUNT_MAX) {
1626                         ea_idebug(inode, "block %lu refcount %d>=%d",
1627                                   (unsigned long) ce->e_block,
1628                                   le32_to_cpu(BHDR(bh)->h_refcount),
1629                                           EXT4_XATTR_REFCOUNT_MAX);
1630                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1631                         *pce = ce;
1632                         return bh;
1633                 }
1634                 brelse(bh);
1635                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1636         }
1637         return NULL;
1638 }
1639
1640 #define NAME_HASH_SHIFT 5
1641 #define VALUE_HASH_SHIFT 16
1642
1643 /*
1644  * ext4_xattr_hash_entry()
1645  *
1646  * Compute the hash of an extended attribute.
1647  */
1648 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1649                                          struct ext4_xattr_entry *entry)
1650 {
1651         __u32 hash = 0;
1652         char *name = entry->e_name;
1653         int n;
1654
1655         for (n = 0; n < entry->e_name_len; n++) {
1656                 hash = (hash << NAME_HASH_SHIFT) ^
1657                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1658                        *name++;
1659         }
1660
1661         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1662                 __le32 *value = (__le32 *)((char *)header +
1663                         le16_to_cpu(entry->e_value_offs));
1664                 for (n = (le32_to_cpu(entry->e_value_size) +
1665                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1666                         hash = (hash << VALUE_HASH_SHIFT) ^
1667                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1668                                le32_to_cpu(*value++);
1669                 }
1670         }
1671         entry->e_hash = cpu_to_le32(hash);
1672 }
1673
1674 #undef NAME_HASH_SHIFT
1675 #undef VALUE_HASH_SHIFT
1676
1677 #define BLOCK_HASH_SHIFT 16
1678
1679 /*
1680  * ext4_xattr_rehash()
1681  *
1682  * Re-compute the extended attribute hash value after an entry has changed.
1683  */
1684 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1685                               struct ext4_xattr_entry *entry)
1686 {
1687         struct ext4_xattr_entry *here;
1688         __u32 hash = 0;
1689
1690         ext4_xattr_hash_entry(header, entry);
1691         here = ENTRY(header+1);
1692         while (!IS_LAST_ENTRY(here)) {
1693                 if (!here->e_hash) {
1694                         /* Block is not shared if an entry's hash value == 0 */
1695                         hash = 0;
1696                         break;
1697                 }
1698                 hash = (hash << BLOCK_HASH_SHIFT) ^
1699                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1700                        le32_to_cpu(here->e_hash);
1701                 here = EXT4_XATTR_NEXT(here);
1702         }
1703         header->h_hash = cpu_to_le32(hash);
1704 }
1705
1706 #undef BLOCK_HASH_SHIFT
1707
1708 int __init
1709 ext4_init_xattr(void)
1710 {
1711         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1712         if (!ext4_xattr_cache)
1713                 return -ENOMEM;
1714         return 0;
1715 }
1716
1717 void
1718 ext4_exit_xattr(void)
1719 {
1720         if (ext4_xattr_cache)
1721                 mb_cache_destroy(ext4_xattr_cache);
1722         ext4_xattr_cache = NULL;
1723 }