fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   5  *
   6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   7  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  13  *  and Andreas Gruenbacher <agruen@suse.de>.
  14  */
  15
  16 /*
  17  * Extended attributes are stored directly in inodes (on file systems with
  18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19  * field contains the block number if an inode uses an additional block. All
  20  * attributes must fit in the inode and one additional block. Blocks that
  21  * contain the identical set of attributes may be shared among several inodes.
  22  * Identical blocks are detected by keeping a cache of blocks that have
  23  * recently been accessed.
  24  *
  25  * The attributes in inodes and on blocks have a different header; the entries
  26  * are stored in the same format:
  27  *
  28  *   +------------------+
  29  *   | header           |
  30  *   | entry 1          | |
  31  *   | entry 2          | | growing downwards
  32  *   | entry 3          | v
  33  *   | four null bytes  |
  34  *   | . . .            |
  35  *   | value 1          | ^
  36  *   | value 3          | | growing upwards
  37  *   | value 2          | |
  38  *   +------------------+
  39  *
  40  * The header is followed by multiple entry descriptors. In disk blocks, the
  41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42  * attribute values are aligned to the end of the block in no specific order.
  43  *
  44  * Locking strategy
  45  * ----------------
  46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47  * EA blocks are only changed if they are exclusive to an inode, so
  48  * holding xattr_sem also means that nothing but the EA block's reference
  49  * count can change. Multiple writers to the same block are synchronized
  50  * by the buffer lock.
  51  */
  52
  53 #include <linux/init.h>
  54 #include <linux/fs.h>
  55 #include <linux/slab.h>
  56 #include <linux/mbcache.h>
  57 #include <linux/quotaops.h>
  58 #include <linux/rwsem.h>
  59 #include "ext4_jbd2.h"
  60 #include "ext4.h"
  61 #include "xattr.h"
  62 #include "acl.h"
  63
  64 #ifdef EXT4_XATTR_DEBUG
  65 # define ea_idebug(inode, f...) do { \
  66                 printk(KERN_DEBUG "inode %s:%lu: ", \
  67                         inode->i_sb->s_id, inode->i_ino); \
  68                 printk(f); \
  69                 printk("\n"); \
  70         } while (0)
  71 # define ea_bdebug(bh, f...) do { \
  72                 char b[BDEVNAME_SIZE]; \
  73                 printk(KERN_DEBUG "block %s:%lu: ", \
  74                         bdevname(bh->b_bdev, b), \
  75                         (unsigned long) bh->b_blocknr); \
  76                 printk(f); \
  77                 printk("\n"); \
  78         } while (0)
  79 #else
  80 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  81 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  82 #endif
  83
  84 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
  85 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  86                                                  struct ext4_xattr_header *,
  87                                                  struct mb_cache_entry **);
  88 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  89                               struct ext4_xattr_entry *);
  90 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  91                            size_t buffer_size);
  92
  93 static const struct xattr_handler *ext4_xattr_handler_map[] = {
  94         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  95 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  96         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  97         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  98 #endif
  99         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 100 #ifdef CONFIG_EXT4_FS_SECURITY
 101         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 102 #endif
 103 };
 104
 105 const struct xattr_handler *ext4_xattr_handlers[] = {
 106         &ext4_xattr_user_handler,
 107         &ext4_xattr_trusted_handler,
 108 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 109         &posix_acl_access_xattr_handler,
 110         &posix_acl_default_xattr_handler,
 111 #endif
 112 #ifdef CONFIG_EXT4_FS_SECURITY
 113         &ext4_xattr_security_handler,
 114 #endif
 115         NULL
 116 };
 117
 118 #define EXT4_GET_MB_CACHE(inode)        (((struct ext4_sb_info *) \
 119                                 inode->i_sb->s_fs_info)->s_mb_cache)
 120
 121 static __le32 ext4_xattr_block_csum(struct inode *inode,
 122                                     sector_t block_nr,
 123                                     struct ext4_xattr_header *hdr)
 124 {
 125         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 126         __u32 csum;
 127         __le32 save_csum;
 128         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 129
 130         save_csum = hdr->h_checksum;
 131         hdr->h_checksum = 0;
 132         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 133                            sizeof(dsk_block_nr));
 134         csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
 135                            EXT4_BLOCK_SIZE(inode->i_sb));
 136
 137         hdr->h_checksum = save_csum;
 138         return cpu_to_le32(csum);
 139 }
 140
 141 static int ext4_xattr_block_csum_verify(struct inode *inode,
 142                                         sector_t block_nr,
 143                                         struct ext4_xattr_header *hdr)
 144 {
 145         if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 146                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
 147             (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 148                 return 0;
 149         return 1;
 150 }
 151
 152 static void ext4_xattr_block_csum_set(struct inode *inode,
 153                                       sector_t block_nr,
 154                                       struct ext4_xattr_header *hdr)
 155 {
 156         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 157                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 158                 return;
 159
 160         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 161 }
 162
 163 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 164                                                 struct inode *inode,
 165                                                 struct buffer_head *bh)
 166 {
 167         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 168         return ext4_handle_dirty_metadata(handle, inode, bh);
 169 }
 170
 171 static inline const struct xattr_handler *
 172 ext4_xattr_handler(int name_index)
 173 {
 174         const struct xattr_handler *handler = NULL;
 175
 176         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 177                 handler = ext4_xattr_handler_map[name_index];
 178         return handler;
 179 }
 180
 181 /*
 182  * Inode operation listxattr()
 183  *
 184  * dentry->d_inode->i_mutex: don't care
 185  */
 186 ssize_t
 187 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 188 {
 189         return ext4_xattr_list(dentry, buffer, size);
 190 }
 191
 192 static int
 193 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 194 {
 195         while (!IS_LAST_ENTRY(entry)) {
 196                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
 197                 if ((void *)next >= end)
 198                         return -EIO;
 199                 entry = next;
 200         }
 201         return 0;
 202 }
 203
 204 static inline int
 205 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 206 {
 207         int error;
 208
 209         if (buffer_verified(bh))
 210                 return 0;
 211
 212         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 213             BHDR(bh)->h_blocks != cpu_to_le32(1))
 214                 return -EIO;
 215         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 216                 return -EIO;
 217         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 218         if (!error)
 219                 set_buffer_verified(bh);
 220         return error;
 221 }
 222
 223 static inline int
 224 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 225 {
 226         size_t value_size = le32_to_cpu(entry->e_value_size);
 227
 228         if (entry->e_value_block != 0 || value_size > size ||
 229             le16_to_cpu(entry->e_value_offs) + value_size > size)
 230                 return -EIO;
 231         return 0;
 232 }
 233
 234 static int
 235 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 236                       const char *name, size_t size, int sorted)
 237 {
 238         struct ext4_xattr_entry *entry;
 239         size_t name_len;
 240         int cmp = 1;
 241
 242         if (name == NULL)
 243                 return -EINVAL;
 244         name_len = strlen(name);
 245         entry = *pentry;
 246         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 247                 cmp = name_index - entry->e_name_index;
 248                 if (!cmp)
 249                         cmp = name_len - entry->e_name_len;
 250                 if (!cmp)
 251                         cmp = memcmp(name, entry->e_name, name_len);
 252                 if (cmp <= 0 && (sorted || cmp == 0))
 253                         break;
 254         }
 255         *pentry = entry;
 256         if (!cmp && ext4_xattr_check_entry(entry, size))
 257                         return -EIO;
 258         return cmp ? -ENODATA : 0;
 259 }
 260
 261 static int
 262 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 263                      void *buffer, size_t buffer_size)
 264 {
 265         struct buffer_head *bh = NULL;
 266         struct ext4_xattr_entry *entry;
 267         size_t size;
 268         int error;
 269         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 270
 271         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 272                   name_index, name, buffer, (long)buffer_size);
 273
 274         error = -ENODATA;
 275         if (!EXT4_I(inode)->i_file_acl)
 276                 goto cleanup;
 277         ea_idebug(inode, "reading block %llu",
 278                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 279         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 280         if (!bh)
 281                 goto cleanup;
 282         ea_bdebug(bh, "b_count=%d, refcount=%d",
 283                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 284         if (ext4_xattr_check_block(inode, bh)) {
 285 bad_block:
 286                 EXT4_ERROR_INODE(inode, "bad block %llu",
 287                                  EXT4_I(inode)->i_file_acl);
 288                 error = -EIO;
 289                 goto cleanup;
 290         }
 291         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 292         entry = BFIRST(bh);
 293         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 294         if (error == -EIO)
 295                 goto bad_block;
 296         if (error)
 297                 goto cleanup;
 298         size = le32_to_cpu(entry->e_value_size);
 299         if (buffer) {
 300                 error = -ERANGE;
 301                 if (size > buffer_size)
 302                         goto cleanup;
 303                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 304                        size);
 305         }
 306         error = size;
 307
 308 cleanup:
 309         brelse(bh);
 310         return error;
 311 }
 312
 313 int
 314 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 315                      void *buffer, size_t buffer_size)
 316 {
 317         struct ext4_xattr_ibody_header *header;
 318         struct ext4_xattr_entry *entry;
 319         struct ext4_inode *raw_inode;
 320         struct ext4_iloc iloc;
 321         size_t size;
 322         void *end;
 323         int error;
 324
 325         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 326                 return -ENODATA;
 327         error = ext4_get_inode_loc(inode, &iloc);
 328         if (error)
 329                 return error;
 330         raw_inode = ext4_raw_inode(&iloc);
 331         header = IHDR(inode, raw_inode);
 332         entry = IFIRST(header);
 333         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 334         error = ext4_xattr_check_names(entry, end);
 335         if (error)
 336                 goto cleanup;
 337         error = ext4_xattr_find_entry(&entry, name_index, name,
 338                                       end - (void *)entry, 0);
 339         if (error)
 340                 goto cleanup;
 341         size = le32_to_cpu(entry->e_value_size);
 342         if (buffer) {
 343                 error = -ERANGE;
 344                 if (size > buffer_size)
 345                         goto cleanup;
 346                 memcpy(buffer, (void *)IFIRST(header) +
 347                        le16_to_cpu(entry->e_value_offs), size);
 348         }
 349         error = size;
 350
 351 cleanup:
 352         brelse(iloc.bh);
 353         return error;
 354 }
 355
 356 /*
 357  * ext4_xattr_get()
 358  *
 359  * Copy an extended attribute into the buffer
 360  * provided, or compute the buffer size required.
 361  * Buffer is NULL to compute the size of the buffer required.
 362  *
 363  * Returns a negative error number on failure, or the number of bytes
 364  * used / required on success.
 365  */
 366 int
 367 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 368                void *buffer, size_t buffer_size)
 369 {
 370         int error;
 371
 372         down_read(&EXT4_I(inode)->xattr_sem);
 373         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 374                                      buffer_size);
 375         if (error == -ENODATA)
 376                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 377                                              buffer_size);
 378         up_read(&EXT4_I(inode)->xattr_sem);
 379         return error;
 380 }
 381
 382 static int
 383 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 384                         char *buffer, size_t buffer_size)
 385 {
 386         size_t rest = buffer_size;
 387
 388         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 389                 const struct xattr_handler *handler =
 390                         ext4_xattr_handler(entry->e_name_index);
 391
 392                 if (handler) {
 393                         size_t size = handler->list(dentry, buffer, rest,
 394                                                     entry->e_name,
 395                                                     entry->e_name_len,
 396                                                     handler->flags);
 397                         if (buffer) {
 398                                 if (size > rest)
 399                                         return -ERANGE;
 400                                 buffer += size;
 401                         }
 402                         rest -= size;
 403                 }
 404         }
 405         return buffer_size - rest;
 406 }
 407
 408 static int
 409 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 410 {
 411         struct inode *inode = dentry->d_inode;
 412         struct buffer_head *bh = NULL;
 413         int error;
 414         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 415
 416         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 417                   buffer, (long)buffer_size);
 418
 419         error = 0;
 420         if (!EXT4_I(inode)->i_file_acl)
 421                 goto cleanup;
 422         ea_idebug(inode, "reading block %llu",
 423                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 424         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 425         error = -EIO;
 426         if (!bh)
 427                 goto cleanup;
 428         ea_bdebug(bh, "b_count=%d, refcount=%d",
 429                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 430         if (ext4_xattr_check_block(inode, bh)) {
 431                 EXT4_ERROR_INODE(inode, "bad block %llu",
 432                                  EXT4_I(inode)->i_file_acl);
 433                 error = -EIO;
 434                 goto cleanup;
 435         }
 436         ext4_xattr_cache_insert(ext4_mb_cache, bh);
 437         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 438
 439 cleanup:
 440         brelse(bh);
 441
 442         return error;
 443 }
 444
 445 static int
 446 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 447 {
 448         struct inode *inode = dentry->d_inode;
 449         struct ext4_xattr_ibody_header *header;
 450         struct ext4_inode *raw_inode;
 451         struct ext4_iloc iloc;
 452         void *end;
 453         int error;
 454
 455         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 456                 return 0;
 457         error = ext4_get_inode_loc(inode, &iloc);
 458         if (error)
 459                 return error;
 460         raw_inode = ext4_raw_inode(&iloc);
 461         header = IHDR(inode, raw_inode);
 462         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 463         error = ext4_xattr_check_names(IFIRST(header), end);
 464         if (error)
 465                 goto cleanup;
 466         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 467                                         buffer, buffer_size);
 468
 469 cleanup:
 470         brelse(iloc.bh);
 471         return error;
 472 }
 473
 474 /*
 475  * ext4_xattr_list()
 476  *
 477  * Copy a list of attribute names into the buffer
 478  * provided, or compute the buffer size required.
 479  * Buffer is NULL to compute the size of the buffer required.
 480  *
 481  * Returns a negative error number on failure, or the number of bytes
 482  * used / required on success.
 483  */
 484 static int
 485 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 486 {
 487         int ret, ret2;
 488
 489         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 490         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 491         if (ret < 0)
 492                 goto errout;
 493         if (buffer) {
 494                 buffer += ret;
 495                 buffer_size -= ret;
 496         }
 497         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 498         if (ret < 0)
 499                 goto errout;
 500         ret += ret2;
 501 errout:
 502         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 503         return ret;
 504 }
 505
 506 /*
 507  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 508  * not set, set it.
 509  */
 510 static void ext4_xattr_update_super_block(handle_t *handle,
 511                                           struct super_block *sb)
 512 {
 513         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 514                 return;
 515
 516         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 517                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 518                 ext4_handle_dirty_super(handle, sb);
 519         }
 520 }
 521
 522 /*
 523  * Release the xattr block BH: If the reference count is > 1, decrement it;
 524  * otherwise free the block.
 525  */
 526 static void
 527 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 528                          struct buffer_head *bh)
 529 {
 530         struct mb_cache_entry *ce = NULL;
 531         int error = 0;
 532         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 533
 534         ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
 535         error = ext4_journal_get_write_access(handle, bh);
 536         if (error)
 537                 goto out;
 538
 539         lock_buffer(bh);
 540         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 541                 ea_bdebug(bh, "refcount now=0; freeing");
 542                 if (ce)
 543                         mb_cache_entry_free(ce);
 544                 get_bh(bh);
 545                 unlock_buffer(bh);
 546                 ext4_free_blocks(handle, inode, bh, 0, 1,
 547                                  EXT4_FREE_BLOCKS_METADATA |
 548                                  EXT4_FREE_BLOCKS_FORGET);
 549         } else {
 550                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 551                 if (ce)
 552                         mb_cache_entry_release(ce);
 553                 /*
 554                  * Beware of this ugliness: Releasing of xattr block references
 555                  * from different inodes can race and so we have to protect
 556                  * from a race where someone else frees the block (and releases
 557                  * its journal_head) before we are done dirtying the buffer. In
 558                  * nojournal mode this race is harmless and we actually cannot
 559                  * call ext4_handle_dirty_xattr_block() with locked buffer as
 560                  * that function can call sync_dirty_buffer() so for that case
 561                  * we handle the dirtying after unlocking the buffer.
 562                  */
 563                 if (ext4_handle_valid(handle))
 564                         error = ext4_handle_dirty_xattr_block(handle, inode,
 565                                                               bh);
 566                 unlock_buffer(bh);
 567                 if (!ext4_handle_valid(handle))
 568                         error = ext4_handle_dirty_xattr_block(handle, inode,
 569                                                               bh);
 570                 if (IS_SYNC(inode))
 571                         ext4_handle_sync(handle);
 572                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
 573                 ea_bdebug(bh, "refcount now=%d; releasing",
 574                           le32_to_cpu(BHDR(bh)->h_refcount));
 575         }
 576 out:
 577         ext4_std_error(inode->i_sb, error);
 578         return;
 579 }
 580
 581 /*
 582  * Find the available free space for EAs. This also returns the total number of
 583  * bytes used by EA entries.
 584  */
 585 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 586                                     size_t *min_offs, void *base, int *total)
 587 {
 588         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 589                 if (!last->e_value_block && last->e_value_size) {
 590                         size_t offs = le16_to_cpu(last->e_value_offs);
 591                         if (offs < *min_offs)
 592                                 *min_offs = offs;
 593                 }
 594                 if (total)
 595                         *total += EXT4_XATTR_LEN(last->e_name_len);
 596         }
 597         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 598 }
 599
 600 static int
 601 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 602 {
 603         struct ext4_xattr_entry *last;
 604         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 605
 606         /* Compute min_offs and last. */
 607         last = s->first;
 608         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 609                 if (!last->e_value_block && last->e_value_size) {
 610                         size_t offs = le16_to_cpu(last->e_value_offs);
 611                         if (offs < min_offs)
 612                                 min_offs = offs;
 613                 }
 614         }
 615         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 616         if (!s->not_found) {
 617                 if (!s->here->e_value_block && s->here->e_value_size) {
 618                         size_t size = le32_to_cpu(s->here->e_value_size);
 619                         free += EXT4_XATTR_SIZE(size);
 620                 }
 621                 free += EXT4_XATTR_LEN(name_len);
 622         }
 623         if (i->value) {
 624                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 625                     free < EXT4_XATTR_LEN(name_len) +
 626                            EXT4_XATTR_SIZE(i->value_len))
 627                         return -ENOSPC;
 628         }
 629
 630         if (i->value && s->not_found) {
 631                 /* Insert the new name. */
 632                 size_t size = EXT4_XATTR_LEN(name_len);
 633                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 634                 memmove((void *)s->here + size, s->here, rest);
 635                 memset(s->here, 0, size);
 636                 s->here->e_name_index = i->name_index;
 637                 s->here->e_name_len = name_len;
 638                 memcpy(s->here->e_name, i->name, name_len);
 639         } else {
 640                 if (!s->here->e_value_block && s->here->e_value_size) {
 641                         void *first_val = s->base + min_offs;
 642                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 643                         void *val = s->base + offs;
 644                         size_t size = EXT4_XATTR_SIZE(
 645                                 le32_to_cpu(s->here->e_value_size));
 646
 647                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 648                                 /* The old and the new value have the same
 649                                    size. Just replace. */
 650                                 s->here->e_value_size =
 651                                         cpu_to_le32(i->value_len);
 652                                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
 653                                         memset(val, 0, size);
 654                                 } else {
 655                                         /* Clear pad bytes first. */
 656                                         memset(val + size - EXT4_XATTR_PAD, 0,
 657                                                EXT4_XATTR_PAD);
 658                                         memcpy(val, i->value, i->value_len);
 659                                 }
 660                                 return 0;
 661                         }
 662
 663                         /* Remove the old value. */
 664                         memmove(first_val + size, first_val, val - first_val);
 665                         memset(first_val, 0, size);
 666                         s->here->e_value_size = 0;
 667                         s->here->e_value_offs = 0;
 668                         min_offs += size;
 669
 670                         /* Adjust all value offsets. */
 671                         last = s->first;
 672                         while (!IS_LAST_ENTRY(last)) {
 673                                 size_t o = le16_to_cpu(last->e_value_offs);
 674                                 if (!last->e_value_block &&
 675                                     last->e_value_size && o < offs)
 676                                         last->e_value_offs =
 677                                                 cpu_to_le16(o + size);
 678                                 last = EXT4_XATTR_NEXT(last);
 679                         }
 680                 }
 681                 if (!i->value) {
 682                         /* Remove the old name. */
 683                         size_t size = EXT4_XATTR_LEN(name_len);
 684                         last = ENTRY((void *)last - size);
 685                         memmove(s->here, (void *)s->here + size,
 686                                 (void *)last - (void *)s->here + sizeof(__u32));
 687                         memset(last, 0, size);
 688                 }
 689         }
 690
 691         if (i->value) {
 692                 /* Insert the new value. */
 693                 s->here->e_value_size = cpu_to_le32(i->value_len);
 694                 if (i->value_len) {
 695                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 696                         void *val = s->base + min_offs - size;
 697                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 698                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
 699                                 memset(val, 0, size);
 700                         } else {
 701                                 /* Clear the pad bytes first. */
 702                                 memset(val + size - EXT4_XATTR_PAD, 0,
 703                                        EXT4_XATTR_PAD);
 704                                 memcpy(val, i->value, i->value_len);
 705                         }
 706                 }
 707         }
 708         return 0;
 709 }
 710
 711 struct ext4_xattr_block_find {
 712         struct ext4_xattr_search s;
 713         struct buffer_head *bh;
 714 };
 715
 716 static int
 717 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 718                       struct ext4_xattr_block_find *bs)
 719 {
 720         struct super_block *sb = inode->i_sb;
 721         int error;
 722
 723         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 724                   i->name_index, i->name, i->value, (long)i->value_len);
 725
 726         if (EXT4_I(inode)->i_file_acl) {
 727                 /* The inode already has an extended attribute block. */
 728                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 729                 error = -EIO;
 730                 if (!bs->bh)
 731                         goto cleanup;
 732                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 733                         atomic_read(&(bs->bh->b_count)),
 734                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 735                 if (ext4_xattr_check_block(inode, bs->bh)) {
 736                         EXT4_ERROR_INODE(inode, "bad block %llu",
 737                                          EXT4_I(inode)->i_file_acl);
 738                         error = -EIO;
 739                         goto cleanup;
 740                 }
 741                 /* Find the named attribute. */
 742                 bs->s.base = BHDR(bs->bh);
 743                 bs->s.first = BFIRST(bs->bh);
 744                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 745                 bs->s.here = bs->s.first;
 746                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 747                                               i->name, bs->bh->b_size, 1);
 748                 if (error && error != -ENODATA)
 749                         goto cleanup;
 750                 bs->s.not_found = error;
 751         }
 752         error = 0;
 753
 754 cleanup:
 755         return error;
 756 }
 757
 758 static int
 759 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 760                      struct ext4_xattr_info *i,
 761                      struct ext4_xattr_block_find *bs)
 762 {
 763         struct super_block *sb = inode->i_sb;
 764         struct buffer_head *new_bh = NULL;
 765         struct ext4_xattr_search *s = &bs->s;
 766         struct mb_cache_entry *ce = NULL;
 767         int error = 0;
 768         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 769
 770 #define header(x) ((struct ext4_xattr_header *)(x))
 771
 772         if (i->value && i->value_len > sb->s_blocksize)
 773                 return -ENOSPC;
 774         if (s->base) {
 775                 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
 776                                         bs->bh->b_blocknr);
 777                 error = ext4_journal_get_write_access(handle, bs->bh);
 778                 if (error)
 779                         goto cleanup;
 780                 lock_buffer(bs->bh);
 781
 782                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 783                         if (ce) {
 784                                 mb_cache_entry_free(ce);
 785                                 ce = NULL;
 786                         }
 787                         ea_bdebug(bs->bh, "modifying in-place");
 788                         error = ext4_xattr_set_entry(i, s);
 789                         if (!error) {
 790                                 if (!IS_LAST_ENTRY(s->first))
 791                                         ext4_xattr_rehash(header(s->base),
 792                                                           s->here);
 793                                 ext4_xattr_cache_insert(ext4_mb_cache,
 794                                         bs->bh);
 795                         }
 796                         unlock_buffer(bs->bh);
 797                         if (error == -EIO)
 798                                 goto bad_block;
 799                         if (!error)
 800                                 error = ext4_handle_dirty_xattr_block(handle,
 801                                                                       inode,
 802                                                                       bs->bh);
 803                         if (error)
 804                                 goto cleanup;
 805                         goto inserted;
 806                 } else {
 807                         int offset = (char *)s->here - bs->bh->b_data;
 808
 809                         unlock_buffer(bs->bh);
 810                         if (ce) {
 811                                 mb_cache_entry_release(ce);
 812                                 ce = NULL;
 813                         }
 814                         ea_bdebug(bs->bh, "cloning");
 815                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 816                         error = -ENOMEM;
 817                         if (s->base == NULL)
 818                                 goto cleanup;
 819                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 820                         s->first = ENTRY(header(s->base)+1);
 821                         header(s->base)->h_refcount = cpu_to_le32(1);
 822                         s->here = ENTRY(s->base + offset);
 823                         s->end = s->base + bs->bh->b_size;
 824                 }
 825         } else {
 826                 /* Allocate a buffer where we construct the new block. */
 827                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 828                 /* assert(header == s->base) */
 829                 error = -ENOMEM;
 830                 if (s->base == NULL)
 831                         goto cleanup;
 832                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 833                 header(s->base)->h_blocks = cpu_to_le32(1);
 834                 header(s->base)->h_refcount = cpu_to_le32(1);
 835                 s->first = ENTRY(header(s->base)+1);
 836                 s->here = ENTRY(header(s->base)+1);
 837                 s->end = s->base + sb->s_blocksize;
 838         }
 839
 840         error = ext4_xattr_set_entry(i, s);
 841         if (error == -EIO)
 842                 goto bad_block;
 843         if (error)
 844                 goto cleanup;
 845         if (!IS_LAST_ENTRY(s->first))
 846                 ext4_xattr_rehash(header(s->base), s->here);
 847
 848 inserted:
 849         if (!IS_LAST_ENTRY(s->first)) {
 850                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 851                 if (new_bh) {
 852                         /* We found an identical block in the cache. */
 853                         if (new_bh == bs->bh)
 854                                 ea_bdebug(new_bh, "keeping");
 855                         else {
 856                                 /* The old block is released after updating
 857                                    the inode. */
 858                                 error = dquot_alloc_block(inode,
 859                                                 EXT4_C2B(EXT4_SB(sb), 1));
 860                                 if (error)
 861                                         goto cleanup;
 862                                 error = ext4_journal_get_write_access(handle,
 863                                                                       new_bh);
 864                                 if (error)
 865                                         goto cleanup_dquot;
 866                                 lock_buffer(new_bh);
 867                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 868                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 869                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 870                                 unlock_buffer(new_bh);
 871                                 error = ext4_handle_dirty_xattr_block(handle,
 872                                                                       inode,
 873                                                                       new_bh);
 874                                 if (error)
 875                                         goto cleanup_dquot;
 876                         }
 877                         mb_cache_entry_release(ce);
 878                         ce = NULL;
 879                 } else if (bs->bh && s->base == bs->bh->b_data) {
 880                         /* We were modifying this block in-place. */
 881                         ea_bdebug(bs->bh, "keeping this block");
 882                         new_bh = bs->bh;
 883                         get_bh(new_bh);
 884                 } else {
 885                         /* We need to allocate a new block */
 886                         ext4_fsblk_t goal, block;
 887
 888                         goal = ext4_group_first_block_no(sb,
 889                                                 EXT4_I(inode)->i_block_group);
 890
 891                         /* non-extent files can't have physical blocks past 2^32 */
 892                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 893                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 894
 895                         /*
 896                          * take i_data_sem because we will test
 897                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 898                          */
 899                         down_read((&EXT4_I(inode)->i_data_sem));
 900                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 901                                                      NULL, &error);
 902                         up_read((&EXT4_I(inode)->i_data_sem));
 903                         if (error)
 904                                 goto cleanup;
 905
 906                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 907                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 908
 909                         ea_idebug(inode, "creating block %llu",
 910                                   (unsigned long long)block);
 911
 912                         new_bh = sb_getblk(sb, block);
 913                         if (unlikely(!new_bh)) {
 914                                 error = -ENOMEM;
 915 getblk_failed:
 916                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 917                                                  EXT4_FREE_BLOCKS_METADATA);
 918                                 goto cleanup;
 919                         }
 920                         lock_buffer(new_bh);
 921                         error = ext4_journal_get_create_access(handle, new_bh);
 922                         if (error) {
 923                                 unlock_buffer(new_bh);
 924                                 error = -EIO;
 925                                 goto getblk_failed;
 926                         }
 927                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 928                         set_buffer_uptodate(new_bh);
 929                         unlock_buffer(new_bh);
 930                         ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
 931                         error = ext4_handle_dirty_xattr_block(handle,
 932                                                               inode, new_bh);
 933                         if (error)
 934                                 goto cleanup;
 935                 }
 936         }
 937
 938         /* Update the inode. */
 939         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 940
 941         /* Drop the previous xattr block. */
 942         if (bs->bh && bs->bh != new_bh)
 943                 ext4_xattr_release_block(handle, inode, bs->bh);
 944         error = 0;
 945
 946 cleanup:
 947         if (ce)
 948                 mb_cache_entry_release(ce);
 949         brelse(new_bh);
 950         if (!(bs->bh && s->base == bs->bh->b_data))
 951                 kfree(s->base);
 952
 953         return error;
 954
 955 cleanup_dquot:
 956         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
 957         goto cleanup;
 958
 959 bad_block:
 960         EXT4_ERROR_INODE(inode, "bad block %llu",
 961                          EXT4_I(inode)->i_file_acl);
 962         goto cleanup;
 963
 964 #undef header
 965 }
 966
 967 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 968                           struct ext4_xattr_ibody_find *is)
 969 {
 970         struct ext4_xattr_ibody_header *header;
 971         struct ext4_inode *raw_inode;
 972         int error;
 973
 974         if (EXT4_I(inode)->i_extra_isize == 0)
 975                 return 0;
 976         raw_inode = ext4_raw_inode(&is->iloc);
 977         header = IHDR(inode, raw_inode);
 978         is->s.base = is->s.first = IFIRST(header);
 979         is->s.here = is->s.first;
 980         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 981         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 982                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 983                 if (error)
 984                         return error;
 985                 /* Find the named attribute. */
 986                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 987                                               i->name, is->s.end -
 988                                               (void *)is->s.base, 0);
 989                 if (error && error != -ENODATA)
 990                         return error;
 991                 is->s.not_found = error;
 992         }
 993         return 0;
 994 }
 995
 996 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 997                                 struct ext4_xattr_info *i,
 998                                 struct ext4_xattr_ibody_find *is)
 999 {
1000         struct ext4_xattr_ibody_header *header;
1001         struct ext4_xattr_search *s = &is->s;
1002         int error;
1003
1004         if (EXT4_I(inode)->i_extra_isize == 0)
1005                 return -ENOSPC;
1006         error = ext4_xattr_set_entry(i, s);
1007         if (error) {
1008                 if (error == -ENOSPC &&
1009                     ext4_has_inline_data(inode)) {
1010                         error = ext4_try_to_evict_inline_data(handle, inode,
1011                                         EXT4_XATTR_LEN(strlen(i->name) +
1012                                         EXT4_XATTR_SIZE(i->value_len)));
1013                         if (error)
1014                                 return error;
1015                         error = ext4_xattr_ibody_find(inode, i, is);
1016                         if (error)
1017                                 return error;
1018                         error = ext4_xattr_set_entry(i, s);
1019                 }
1020                 if (error)
1021                         return error;
1022         }
1023         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1024         if (!IS_LAST_ENTRY(s->first)) {
1025                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1026                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1027         } else {
1028                 header->h_magic = cpu_to_le32(0);
1029                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1030         }
1031         return 0;
1032 }
1033
1034 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1035                                 struct ext4_xattr_info *i,
1036                                 struct ext4_xattr_ibody_find *is)
1037 {
1038         struct ext4_xattr_ibody_header *header;
1039         struct ext4_xattr_search *s = &is->s;
1040         int error;
1041
1042         if (EXT4_I(inode)->i_extra_isize == 0)
1043                 return -ENOSPC;
1044         error = ext4_xattr_set_entry(i, s);
1045         if (error)
1046                 return error;
1047         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1048         if (!IS_LAST_ENTRY(s->first)) {
1049                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1050                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1051         } else {
1052                 header->h_magic = cpu_to_le32(0);
1053                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1054         }
1055         return 0;
1056 }
1057
1058 /*
1059  * ext4_xattr_set_handle()
1060  *
1061  * Create, replace or remove an extended attribute for this inode.  Value
1062  * is NULL to remove an existing extended attribute, and non-NULL to
1063  * either replace an existing extended attribute, or create a new extended
1064  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1065  * specify that an extended attribute must exist and must not exist
1066  * previous to the call, respectively.
1067  *
1068  * Returns 0, or a negative error number on failure.
1069  */
1070 int
1071 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1072                       const char *name, const void *value, size_t value_len,
1073                       int flags)
1074 {
1075         struct ext4_xattr_info i = {
1076                 .name_index = name_index,
1077                 .name = name,
1078                 .value = value,
1079                 .value_len = value_len,
1080
1081         };
1082         struct ext4_xattr_ibody_find is = {
1083                 .s = { .not_found = -ENODATA, },
1084         };
1085         struct ext4_xattr_block_find bs = {
1086                 .s = { .not_found = -ENODATA, },
1087         };
1088         unsigned long no_expand;
1089         int error;
1090
1091         if (!name)
1092                 return -EINVAL;
1093         if (strlen(name) > 255)
1094                 return -ERANGE;
1095         down_write(&EXT4_I(inode)->xattr_sem);
1096         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1097         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1098
1099         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1100         if (error)
1101                 goto cleanup;
1102
1103         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1104                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1105                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1106                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1107         }
1108
1109         error = ext4_xattr_ibody_find(inode, &i, &is);
1110         if (error)
1111                 goto cleanup;
1112         if (is.s.not_found)
1113                 error = ext4_xattr_block_find(inode, &i, &bs);
1114         if (error)
1115                 goto cleanup;
1116         if (is.s.not_found && bs.s.not_found) {
1117                 error = -ENODATA;
1118                 if (flags & XATTR_REPLACE)
1119                         goto cleanup;
1120                 error = 0;
1121                 if (!value)
1122                         goto cleanup;
1123         } else {
1124                 error = -EEXIST;
1125                 if (flags & XATTR_CREATE)
1126                         goto cleanup;
1127         }
1128         if (!value) {
1129                 if (!is.s.not_found)
1130                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1131                 else if (!bs.s.not_found)
1132                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1133         } else {
1134                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1135                 if (!error && !bs.s.not_found) {
1136                         i.value = NULL;
1137                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1138                 } else if (error == -ENOSPC) {
1139                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1140                                 error = ext4_xattr_block_find(inode, &i, &bs);
1141                                 if (error)
1142                                         goto cleanup;
1143                         }
1144                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1145                         if (error)
1146                                 goto cleanup;
1147                         if (!is.s.not_found) {
1148                                 i.value = NULL;
1149                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1150                                                              &is);
1151                         }
1152                 }
1153         }
1154         if (!error) {
1155                 ext4_xattr_update_super_block(handle, inode->i_sb);
1156                 inode->i_ctime = ext4_current_time(inode);
1157                 if (!value)
1158                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1159                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1160                 /*
1161                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1162                  * error != 0.
1163                  */
1164                 is.iloc.bh = NULL;
1165                 if (IS_SYNC(inode))
1166                         ext4_handle_sync(handle);
1167         }
1168
1169 cleanup:
1170         brelse(is.iloc.bh);
1171         brelse(bs.bh);
1172         if (no_expand == 0)
1173                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1174         up_write(&EXT4_I(inode)->xattr_sem);
1175         return error;
1176 }
1177
1178 /*
1179  * ext4_xattr_set()
1180  *
1181  * Like ext4_xattr_set_handle, but start from an inode. This extended
1182  * attribute modification is a filesystem transaction by itself.
1183  *
1184  * Returns 0, or a negative error number on failure.
1185  */
1186 int
1187 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1188                const void *value, size_t value_len, int flags)
1189 {
1190         handle_t *handle;
1191         int error, retries = 0;
1192         int credits = ext4_jbd2_credits_xattr(inode);
1193
1194 retry:
1195         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1196         if (IS_ERR(handle)) {
1197                 error = PTR_ERR(handle);
1198         } else {
1199                 int error2;
1200
1201                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1202                                               value, value_len, flags);
1203                 error2 = ext4_journal_stop(handle);
1204                 if (error == -ENOSPC &&
1205                     ext4_should_retry_alloc(inode->i_sb, &retries))
1206                         goto retry;
1207                 if (error == 0)
1208                         error = error2;
1209         }
1210
1211         return error;
1212 }
1213
1214 /*
1215  * Shift the EA entries in the inode to create space for the increased
1216  * i_extra_isize.
1217  */
1218 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1219                                      int value_offs_shift, void *to,
1220                                      void *from, size_t n, int blocksize)
1221 {
1222         struct ext4_xattr_entry *last = entry;
1223         int new_offs;
1224
1225         /* Adjust the value offsets of the entries */
1226         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1227                 if (!last->e_value_block && last->e_value_size) {
1228                         new_offs = le16_to_cpu(last->e_value_offs) +
1229                                                         value_offs_shift;
1230                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1231                                  > blocksize);
1232                         last->e_value_offs = cpu_to_le16(new_offs);
1233                 }
1234         }
1235         /* Shift the entries by n bytes */
1236         memmove(to, from, n);
1237 }
1238
1239 /*
1240  * Expand an inode by new_extra_isize bytes when EAs are present.
1241  * Returns 0 on success or negative error number on failure.
1242  */
1243 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1244                                struct ext4_inode *raw_inode, handle_t *handle)
1245 {
1246         struct ext4_xattr_ibody_header *header;
1247         struct ext4_xattr_entry *entry, *last, *first;
1248         struct buffer_head *bh = NULL;
1249         struct ext4_xattr_ibody_find *is = NULL;
1250         struct ext4_xattr_block_find *bs = NULL;
1251         char *buffer = NULL, *b_entry_name = NULL;
1252         size_t min_offs, free;
1253         int total_ino;
1254         void *base, *start, *end;
1255         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1256         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1257
1258         down_write(&EXT4_I(inode)->xattr_sem);
1259 retry:
1260         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1261                 up_write(&EXT4_I(inode)->xattr_sem);
1262                 return 0;
1263         }
1264
1265         header = IHDR(inode, raw_inode);
1266         entry = IFIRST(header);
1267
1268         /*
1269          * Check if enough free space is available in the inode to shift the
1270          * entries ahead by new_extra_isize.
1271          */
1272
1273         base = start = entry;
1274         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1275         min_offs = end - base;
1276         last = entry;
1277         total_ino = sizeof(struct ext4_xattr_ibody_header);
1278
1279         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1280         if (free >= new_extra_isize) {
1281                 entry = IFIRST(header);
1282                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1283                                 - new_extra_isize, (void *)raw_inode +
1284                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1285                                 (void *)header, total_ino,
1286                                 inode->i_sb->s_blocksize);
1287                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1288                 error = 0;
1289                 goto cleanup;
1290         }
1291
1292         /*
1293          * Enough free space isn't available in the inode, check if
1294          * EA block can hold new_extra_isize bytes.
1295          */
1296         if (EXT4_I(inode)->i_file_acl) {
1297                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1298                 error = -EIO;
1299                 if (!bh)
1300                         goto cleanup;
1301                 if (ext4_xattr_check_block(inode, bh)) {
1302                         EXT4_ERROR_INODE(inode, "bad block %llu",
1303                                          EXT4_I(inode)->i_file_acl);
1304                         error = -EIO;
1305                         goto cleanup;
1306                 }
1307                 base = BHDR(bh);
1308                 first = BFIRST(bh);
1309                 end = bh->b_data + bh->b_size;
1310                 min_offs = end - base;
1311                 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1312                 if (free < new_extra_isize) {
1313                         if (!tried_min_extra_isize && s_min_extra_isize) {
1314                                 tried_min_extra_isize++;
1315                                 new_extra_isize = s_min_extra_isize;
1316                                 brelse(bh);
1317                                 goto retry;
1318                         }
1319                         error = -1;
1320                         goto cleanup;
1321                 }
1322         } else {
1323                 free = inode->i_sb->s_blocksize;
1324         }
1325
1326         while (new_extra_isize > 0) {
1327                 size_t offs, size, entry_size;
1328                 struct ext4_xattr_entry *small_entry = NULL;
1329                 struct ext4_xattr_info i = {
1330                         .value = NULL,
1331                         .value_len = 0,
1332                 };
1333                 unsigned int total_size;  /* EA entry size + value size */
1334                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1335                 unsigned int min_total_size = ~0U;
1336
1337                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1338                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1339                 if (!is || !bs) {
1340                         error = -ENOMEM;
1341                         goto cleanup;
1342                 }
1343
1344                 is->s.not_found = -ENODATA;
1345                 bs->s.not_found = -ENODATA;
1346                 is->iloc.bh = NULL;
1347                 bs->bh = NULL;
1348
1349                 last = IFIRST(header);
1350                 /* Find the entry best suited to be pushed into EA block */
1351                 entry = NULL;
1352                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1353                         total_size =
1354                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1355                                         EXT4_XATTR_LEN(last->e_name_len);
1356                         if (total_size <= free && total_size < min_total_size) {
1357                                 if (total_size < new_extra_isize) {
1358                                         small_entry = last;
1359                                 } else {
1360                                         entry = last;
1361                                         min_total_size = total_size;
1362                                 }
1363                         }
1364                 }
1365
1366                 if (entry == NULL) {
1367                         if (small_entry) {
1368                                 entry = small_entry;
1369                         } else {
1370                                 if (!tried_min_extra_isize &&
1371                                     s_min_extra_isize) {
1372                                         tried_min_extra_isize++;
1373                                         new_extra_isize = s_min_extra_isize;
1374                                         kfree(is); is = NULL;
1375                                         kfree(bs); bs = NULL;
1376                                         brelse(bh);
1377                                         goto retry;
1378                                 }
1379                                 error = -1;
1380                                 goto cleanup;
1381                         }
1382                 }
1383                 offs = le16_to_cpu(entry->e_value_offs);
1384                 size = le32_to_cpu(entry->e_value_size);
1385                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1386                 i.name_index = entry->e_name_index,
1387                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1388                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1389                 if (!buffer || !b_entry_name) {
1390                         error = -ENOMEM;
1391                         goto cleanup;
1392                 }
1393                 /* Save the entry name and the entry value */
1394                 memcpy(buffer, (void *)IFIRST(header) + offs,
1395                        EXT4_XATTR_SIZE(size));
1396                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1397                 b_entry_name[entry->e_name_len] = '\0';
1398                 i.name = b_entry_name;
1399
1400                 error = ext4_get_inode_loc(inode, &is->iloc);
1401                 if (error)
1402                         goto cleanup;
1403
1404                 error = ext4_xattr_ibody_find(inode, &i, is);
1405                 if (error)
1406                         goto cleanup;
1407
1408                 /* Remove the chosen entry from the inode */
1409                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1410                 if (error)
1411                         goto cleanup;
1412
1413                 entry = IFIRST(header);
1414                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1415                         shift_bytes = new_extra_isize;
1416                 else
1417                         shift_bytes = entry_size + size;
1418                 /* Adjust the offsets and shift the remaining entries ahead */
1419                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1420                         shift_bytes, (void *)raw_inode +
1421                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1422                         (void *)header, total_ino - entry_size,
1423                         inode->i_sb->s_blocksize);
1424
1425                 extra_isize += shift_bytes;
1426                 new_extra_isize -= shift_bytes;
1427                 EXT4_I(inode)->i_extra_isize = extra_isize;
1428
1429                 i.name = b_entry_name;
1430                 i.value = buffer;
1431                 i.value_len = size;
1432                 error = ext4_xattr_block_find(inode, &i, bs);
1433                 if (error)
1434                         goto cleanup;
1435
1436                 /* Add entry which was removed from the inode into the block */
1437                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1438                 if (error)
1439                         goto cleanup;
1440                 kfree(b_entry_name);
1441                 kfree(buffer);
1442                 b_entry_name = NULL;
1443                 buffer = NULL;
1444                 brelse(is->iloc.bh);
1445                 kfree(is);
1446                 kfree(bs);
1447         }
1448         brelse(bh);
1449         up_write(&EXT4_I(inode)->xattr_sem);
1450         return 0;
1451
1452 cleanup:
1453         kfree(b_entry_name);
1454         kfree(buffer);
1455         if (is)
1456                 brelse(is->iloc.bh);
1457         kfree(is);
1458         kfree(bs);
1459         brelse(bh);
1460         up_write(&EXT4_I(inode)->xattr_sem);
1461         return error;
1462 }
1463
1464
1465
1466 /*
1467  * ext4_xattr_delete_inode()
1468  *
1469  * Free extended attribute resources associated with this inode. This
1470  * is called immediately before an inode is freed. We have exclusive
1471  * access to the inode.
1472  */
1473 void
1474 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1475 {
1476         struct buffer_head *bh = NULL;
1477
1478         if (!EXT4_I(inode)->i_file_acl)
1479                 goto cleanup;
1480         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1481         if (!bh) {
1482                 EXT4_ERROR_INODE(inode, "block %llu read error",
1483                                  EXT4_I(inode)->i_file_acl);
1484                 goto cleanup;
1485         }
1486         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1487             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1488                 EXT4_ERROR_INODE(inode, "bad block %llu",
1489                                  EXT4_I(inode)->i_file_acl);
1490                 goto cleanup;
1491         }
1492         ext4_xattr_release_block(handle, inode, bh);
1493         EXT4_I(inode)->i_file_acl = 0;
1494
1495 cleanup:
1496         brelse(bh);
1497 }
1498
1499 /*
1500  * ext4_xattr_put_super()
1501  *
1502  * This is called when a file system is unmounted.
1503  */
1504 void
1505 ext4_xattr_put_super(struct super_block *sb)
1506 {
1507         mb_cache_shrink(sb->s_bdev);
1508 }
1509
1510 /*
1511  * ext4_xattr_cache_insert()
1512  *
1513  * Create a new entry in the extended attribute cache, and insert
1514  * it unless such an entry is already in the cache.
1515  *
1516  * Returns 0, or a negative error number on failure.
1517  */
1518 static void
1519 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1520 {
1521         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1522         struct mb_cache_entry *ce;
1523         int error;
1524
1525         ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
1526         if (!ce) {
1527                 ea_bdebug(bh, "out of memory");
1528                 return;
1529         }
1530         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1531         if (error) {
1532                 mb_cache_entry_free(ce);
1533                 if (error == -EBUSY) {
1534                         ea_bdebug(bh, "already in cache");
1535                         error = 0;
1536                 }
1537         } else {
1538                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1539                 mb_cache_entry_release(ce);
1540         }
1541 }
1542
1543 /*
1544  * ext4_xattr_cmp()
1545  *
1546  * Compare two extended attribute blocks for equality.
1547  *
1548  * Returns 0 if the blocks are equal, 1 if they differ, and
1549  * a negative error number on errors.
1550  */
1551 static int
1552 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1553                struct ext4_xattr_header *header2)
1554 {
1555         struct ext4_xattr_entry *entry1, *entry2;
1556
1557         entry1 = ENTRY(header1+1);
1558         entry2 = ENTRY(header2+1);
1559         while (!IS_LAST_ENTRY(entry1)) {
1560                 if (IS_LAST_ENTRY(entry2))
1561                         return 1;
1562                 if (entry1->e_hash != entry2->e_hash ||
1563                     entry1->e_name_index != entry2->e_name_index ||
1564                     entry1->e_name_len != entry2->e_name_len ||
1565                     entry1->e_value_size != entry2->e_value_size ||
1566                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1567                         return 1;
1568                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1569                         return -EIO;
1570                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1571                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1572                            le32_to_cpu(entry1->e_value_size)))
1573                         return 1;
1574
1575                 entry1 = EXT4_XATTR_NEXT(entry1);
1576                 entry2 = EXT4_XATTR_NEXT(entry2);
1577         }
1578         if (!IS_LAST_ENTRY(entry2))
1579                 return 1;
1580         return 0;
1581 }
1582
1583 /*
1584  * ext4_xattr_cache_find()
1585  *
1586  * Find an identical extended attribute block.
1587  *
1588  * Returns a pointer to the block found, or NULL if such a block was
1589  * not found or an error occurred.
1590  */
1591 static struct buffer_head *
1592 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1593                       struct mb_cache_entry **pce)
1594 {
1595         __u32 hash = le32_to_cpu(header->h_hash);
1596         struct mb_cache_entry *ce;
1597         struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1598
1599         if (!header->h_hash)
1600                 return NULL;  /* never share */
1601         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1602 again:
1603         ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
1604                                        hash);
1605         while (ce) {
1606                 struct buffer_head *bh;
1607
1608                 if (IS_ERR(ce)) {
1609                         if (PTR_ERR(ce) == -EAGAIN)
1610                                 goto again;
1611                         break;
1612                 }
1613                 bh = sb_bread(inode->i_sb, ce->e_block);
1614                 if (!bh) {
1615                         EXT4_ERROR_INODE(inode, "block %lu read error",
1616                                          (unsigned long) ce->e_block);
1617                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1618                                 EXT4_XATTR_REFCOUNT_MAX) {
1619                         ea_idebug(inode, "block %lu refcount %d>=%d",
1620                                   (unsigned long) ce->e_block,
1621                                   le32_to_cpu(BHDR(bh)->h_refcount),
1622                                           EXT4_XATTR_REFCOUNT_MAX);
1623                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1624                         *pce = ce;
1625                         return bh;
1626                 }
1627                 brelse(bh);
1628                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1629         }
1630         return NULL;
1631 }
1632
1633 #define NAME_HASH_SHIFT 5
1634 #define VALUE_HASH_SHIFT 16
1635
1636 /*
1637  * ext4_xattr_hash_entry()
1638  *
1639  * Compute the hash of an extended attribute.
1640  */
1641 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1642                                          struct ext4_xattr_entry *entry)
1643 {
1644         __u32 hash = 0;
1645         char *name = entry->e_name;
1646         int n;
1647
1648         for (n = 0; n < entry->e_name_len; n++) {
1649                 hash = (hash << NAME_HASH_SHIFT) ^
1650                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1651                        *name++;
1652         }
1653
1654         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1655                 __le32 *value = (__le32 *)((char *)header +
1656                         le16_to_cpu(entry->e_value_offs));
1657                 for (n = (le32_to_cpu(entry->e_value_size) +
1658                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1659                         hash = (hash << VALUE_HASH_SHIFT) ^
1660                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1661                                le32_to_cpu(*value++);
1662                 }
1663         }
1664         entry->e_hash = cpu_to_le32(hash);
1665 }
1666
1667 #undef NAME_HASH_SHIFT
1668 #undef VALUE_HASH_SHIFT
1669
1670 #define BLOCK_HASH_SHIFT 16
1671
1672 /*
1673  * ext4_xattr_rehash()
1674  *
1675  * Re-compute the extended attribute hash value after an entry has changed.
1676  */
1677 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1678                               struct ext4_xattr_entry *entry)
1679 {
1680         struct ext4_xattr_entry *here;
1681         __u32 hash = 0;
1682
1683         ext4_xattr_hash_entry(header, entry);
1684         here = ENTRY(header+1);
1685         while (!IS_LAST_ENTRY(here)) {
1686                 if (!here->e_hash) {
1687                         /* Block is not shared if an entry's hash value == 0 */
1688                         hash = 0;
1689                         break;
1690                 }
1691                 hash = (hash << BLOCK_HASH_SHIFT) ^
1692                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1693                        le32_to_cpu(here->e_hash);
1694                 here = EXT4_XATTR_NEXT(here);
1695         }
1696         header->h_hash = cpu_to_le32(hash);
1697 }
1698
1699 #undef BLOCK_HASH_SHIFT
1700
1701 #define HASH_BUCKET_BITS        10
1702
1703 struct mb_cache *
1704 ext4_xattr_create_cache(char *name)
1705 {
1706         return mb_cache_create(name, HASH_BUCKET_BITS);
1707 }
1708
1709 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1710 {
1711         if (cache)
1712                 mb_cache_destroy(cache);
1713 }
1714