fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   5  *
   6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   7  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  13  *  and Andreas Gruenbacher <agruen@suse.de>.
  14  */
  15
  16 /*
  17  * Extended attributes are stored directly in inodes (on file systems with
  18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19  * field contains the block number if an inode uses an additional block. All
  20  * attributes must fit in the inode and one additional block. Blocks that
  21  * contain the identical set of attributes may be shared among several inodes.
  22  * Identical blocks are detected by keeping a cache of blocks that have
  23  * recently been accessed.
  24  *
  25  * The attributes in inodes and on blocks have a different header; the entries
  26  * are stored in the same format:
  27  *
  28  *   +------------------+
  29  *   | header           |
  30  *   | entry 1          | |
  31  *   | entry 2          | | growing downwards
  32  *   | entry 3          | v
  33  *   | four null bytes  |
  34  *   | . . .            |
  35  *   | value 1          | ^
  36  *   | value 3          | | growing upwards
  37  *   | value 2          | |
  38  *   +------------------+
  39  *
  40  * The header is followed by multiple entry descriptors. In disk blocks, the
  41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42  * attribute values are aligned to the end of the block in no specific order.
  43  *
  44  * Locking strategy
  45  * ----------------
  46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47  * EA blocks are only changed if they are exclusive to an inode, so
  48  * holding xattr_sem also means that nothing but the EA block's reference
  49  * count can change. Multiple writers to the same block are synchronized
  50  * by the buffer lock.
  51  */
  52
  53 #include <linux/init.h>
  54 #include <linux/fs.h>
  55 #include <linux/slab.h>
  56 #include <linux/mbcache.h>
  57 #include <linux/quotaops.h>
  58 #include <linux/rwsem.h>
  59 #include "ext4_jbd2.h"
  60 #include "ext4.h"
  61 #include "xattr.h"
  62 #include "acl.h"
  63
  64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
  65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
  66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
  67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
  68
  69 #ifdef EXT4_XATTR_DEBUG
  70 # define ea_idebug(inode, f...) do { \
  71                 printk(KERN_DEBUG "inode %s:%lu: ", \
  72                         inode->i_sb->s_id, inode->i_ino); \
  73                 printk(f); \
  74                 printk("\n"); \
  75         } while (0)
  76 # define ea_bdebug(bh, f...) do { \
  77                 char b[BDEVNAME_SIZE]; \
  78                 printk(KERN_DEBUG "block %s:%lu: ", \
  79                         bdevname(bh->b_bdev, b), \
  80                         (unsigned long) bh->b_blocknr); \
  81                 printk(f); \
  82                 printk("\n"); \
  83         } while (0)
  84 #else
  85 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  86 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  87 #endif
  88
  89 static void ext4_xattr_cache_insert(struct buffer_head *);
  90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  91                                                  struct ext4_xattr_header *,
  92                                                  struct mb_cache_entry **);
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  94                               struct ext4_xattr_entry *);
  95 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  96                            size_t buffer_size);
  97
  98 static struct mb_cache *ext4_xattr_cache;
  99
 100 static const struct xattr_handler *ext4_xattr_handler_map[] = {
 101         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 103         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
 104         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
 105 #endif
 106         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 107 #ifdef CONFIG_EXT4_FS_SECURITY
 108         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 109 #endif
 110 };
 111
 112 const struct xattr_handler *ext4_xattr_handlers[] = {
 113         &ext4_xattr_user_handler,
 114         &ext4_xattr_trusted_handler,
 115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 116         &ext4_xattr_acl_access_handler,
 117         &ext4_xattr_acl_default_handler,
 118 #endif
 119 #ifdef CONFIG_EXT4_FS_SECURITY
 120         &ext4_xattr_security_handler,
 121 #endif
 122         NULL
 123 };
 124
 125 static __le32 ext4_xattr_block_csum(struct inode *inode,
 126                                     sector_t block_nr,
 127                                     struct ext4_xattr_header *hdr)
 128 {
 129         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 130         __u32 csum, old;
 131
 132         old = hdr->h_checksum;
 133         hdr->h_checksum = 0;
 134         block_nr = cpu_to_le64(block_nr);
 135         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr,
 136                            sizeof(block_nr));
 137         csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
 138                            EXT4_BLOCK_SIZE(inode->i_sb));
 139
 140         hdr->h_checksum = old;
 141         return cpu_to_le32(csum);
 142 }
 143
 144 static int ext4_xattr_block_csum_verify(struct inode *inode,
 145                                         sector_t block_nr,
 146                                         struct ext4_xattr_header *hdr)
 147 {
 148         if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 149                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
 150             (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 151                 return 0;
 152         return 1;
 153 }
 154
 155 static void ext4_xattr_block_csum_set(struct inode *inode,
 156                                       sector_t block_nr,
 157                                       struct ext4_xattr_header *hdr)
 158 {
 159         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 160                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 161                 return;
 162
 163         hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
 164 }
 165
 166 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
 167                                                 struct inode *inode,
 168                                                 struct buffer_head *bh)
 169 {
 170         ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
 171         return ext4_handle_dirty_metadata(handle, inode, bh);
 172 }
 173
 174 static inline const struct xattr_handler *
 175 ext4_xattr_handler(int name_index)
 176 {
 177         const struct xattr_handler *handler = NULL;
 178
 179         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 180                 handler = ext4_xattr_handler_map[name_index];
 181         return handler;
 182 }
 183
 184 /*
 185  * Inode operation listxattr()
 186  *
 187  * dentry->d_inode->i_mutex: don't care
 188  */
 189 ssize_t
 190 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 191 {
 192         return ext4_xattr_list(dentry, buffer, size);
 193 }
 194
 195 static int
 196 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 197 {
 198         while (!IS_LAST_ENTRY(entry)) {
 199                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
 200                 if ((void *)next >= end)
 201                         return -EIO;
 202                 entry = next;
 203         }
 204         return 0;
 205 }
 206
 207 static inline int
 208 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 209 {
 210         int error;
 211
 212         if (buffer_verified(bh))
 213                 return 0;
 214
 215         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 216             BHDR(bh)->h_blocks != cpu_to_le32(1))
 217                 return -EIO;
 218         if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
 219                 return -EIO;
 220         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 221         if (!error)
 222                 set_buffer_verified(bh);
 223         return error;
 224 }
 225
 226 static inline int
 227 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 228 {
 229         size_t value_size = le32_to_cpu(entry->e_value_size);
 230
 231         if (entry->e_value_block != 0 || value_size > size ||
 232             le16_to_cpu(entry->e_value_offs) + value_size > size)
 233                 return -EIO;
 234         return 0;
 235 }
 236
 237 static int
 238 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 239                       const char *name, size_t size, int sorted)
 240 {
 241         struct ext4_xattr_entry *entry;
 242         size_t name_len;
 243         int cmp = 1;
 244
 245         if (name == NULL)
 246                 return -EINVAL;
 247         name_len = strlen(name);
 248         entry = *pentry;
 249         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 250                 cmp = name_index - entry->e_name_index;
 251                 if (!cmp)
 252                         cmp = name_len - entry->e_name_len;
 253                 if (!cmp)
 254                         cmp = memcmp(name, entry->e_name, name_len);
 255                 if (cmp <= 0 && (sorted || cmp == 0))
 256                         break;
 257         }
 258         *pentry = entry;
 259         if (!cmp && ext4_xattr_check_entry(entry, size))
 260                         return -EIO;
 261         return cmp ? -ENODATA : 0;
 262 }
 263
 264 static int
 265 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 266                      void *buffer, size_t buffer_size)
 267 {
 268         struct buffer_head *bh = NULL;
 269         struct ext4_xattr_entry *entry;
 270         size_t size;
 271         int error;
 272
 273         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 274                   name_index, name, buffer, (long)buffer_size);
 275
 276         error = -ENODATA;
 277         if (!EXT4_I(inode)->i_file_acl)
 278                 goto cleanup;
 279         ea_idebug(inode, "reading block %llu",
 280                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 281         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 282         if (!bh)
 283                 goto cleanup;
 284         ea_bdebug(bh, "b_count=%d, refcount=%d",
 285                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 286         if (ext4_xattr_check_block(inode, bh)) {
 287 bad_block:
 288                 EXT4_ERROR_INODE(inode, "bad block %llu",
 289                                  EXT4_I(inode)->i_file_acl);
 290                 error = -EIO;
 291                 goto cleanup;
 292         }
 293         ext4_xattr_cache_insert(bh);
 294         entry = BFIRST(bh);
 295         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 296         if (error == -EIO)
 297                 goto bad_block;
 298         if (error)
 299                 goto cleanup;
 300         size = le32_to_cpu(entry->e_value_size);
 301         if (buffer) {
 302                 error = -ERANGE;
 303                 if (size > buffer_size)
 304                         goto cleanup;
 305                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 306                        size);
 307         }
 308         error = size;
 309
 310 cleanup:
 311         brelse(bh);
 312         return error;
 313 }
 314
 315 static int
 316 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 317                      void *buffer, size_t buffer_size)
 318 {
 319         struct ext4_xattr_ibody_header *header;
 320         struct ext4_xattr_entry *entry;
 321         struct ext4_inode *raw_inode;
 322         struct ext4_iloc iloc;
 323         size_t size;
 324         void *end;
 325         int error;
 326
 327         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 328                 return -ENODATA;
 329         error = ext4_get_inode_loc(inode, &iloc);
 330         if (error)
 331                 return error;
 332         raw_inode = ext4_raw_inode(&iloc);
 333         header = IHDR(inode, raw_inode);
 334         entry = IFIRST(header);
 335         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 336         error = ext4_xattr_check_names(entry, end);
 337         if (error)
 338                 goto cleanup;
 339         error = ext4_xattr_find_entry(&entry, name_index, name,
 340                                       end - (void *)entry, 0);
 341         if (error)
 342                 goto cleanup;
 343         size = le32_to_cpu(entry->e_value_size);
 344         if (buffer) {
 345                 error = -ERANGE;
 346                 if (size > buffer_size)
 347                         goto cleanup;
 348                 memcpy(buffer, (void *)IFIRST(header) +
 349                        le16_to_cpu(entry->e_value_offs), size);
 350         }
 351         error = size;
 352
 353 cleanup:
 354         brelse(iloc.bh);
 355         return error;
 356 }
 357
 358 /*
 359  * ext4_xattr_get()
 360  *
 361  * Copy an extended attribute into the buffer
 362  * provided, or compute the buffer size required.
 363  * Buffer is NULL to compute the size of the buffer required.
 364  *
 365  * Returns a negative error number on failure, or the number of bytes
 366  * used / required on success.
 367  */
 368 int
 369 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 370                void *buffer, size_t buffer_size)
 371 {
 372         int error;
 373
 374         down_read(&EXT4_I(inode)->xattr_sem);
 375         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 376                                      buffer_size);
 377         if (error == -ENODATA)
 378                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 379                                              buffer_size);
 380         up_read(&EXT4_I(inode)->xattr_sem);
 381         return error;
 382 }
 383
 384 static int
 385 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 386                         char *buffer, size_t buffer_size)
 387 {
 388         size_t rest = buffer_size;
 389
 390         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 391                 const struct xattr_handler *handler =
 392                         ext4_xattr_handler(entry->e_name_index);
 393
 394                 if (handler) {
 395                         size_t size = handler->list(dentry, buffer, rest,
 396                                                     entry->e_name,
 397                                                     entry->e_name_len,
 398                                                     handler->flags);
 399                         if (buffer) {
 400                                 if (size > rest)
 401                                         return -ERANGE;
 402                                 buffer += size;
 403                         }
 404                         rest -= size;
 405                 }
 406         }
 407         return buffer_size - rest;
 408 }
 409
 410 static int
 411 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 412 {
 413         struct inode *inode = dentry->d_inode;
 414         struct buffer_head *bh = NULL;
 415         int error;
 416
 417         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 418                   buffer, (long)buffer_size);
 419
 420         error = 0;
 421         if (!EXT4_I(inode)->i_file_acl)
 422                 goto cleanup;
 423         ea_idebug(inode, "reading block %llu",
 424                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 425         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 426         error = -EIO;
 427         if (!bh)
 428                 goto cleanup;
 429         ea_bdebug(bh, "b_count=%d, refcount=%d",
 430                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 431         if (ext4_xattr_check_block(inode, bh)) {
 432                 EXT4_ERROR_INODE(inode, "bad block %llu",
 433                                  EXT4_I(inode)->i_file_acl);
 434                 error = -EIO;
 435                 goto cleanup;
 436         }
 437         ext4_xattr_cache_insert(bh);
 438         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 439
 440 cleanup:
 441         brelse(bh);
 442
 443         return error;
 444 }
 445
 446 static int
 447 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 448 {
 449         struct inode *inode = dentry->d_inode;
 450         struct ext4_xattr_ibody_header *header;
 451         struct ext4_inode *raw_inode;
 452         struct ext4_iloc iloc;
 453         void *end;
 454         int error;
 455
 456         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 457                 return 0;
 458         error = ext4_get_inode_loc(inode, &iloc);
 459         if (error)
 460                 return error;
 461         raw_inode = ext4_raw_inode(&iloc);
 462         header = IHDR(inode, raw_inode);
 463         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 464         error = ext4_xattr_check_names(IFIRST(header), end);
 465         if (error)
 466                 goto cleanup;
 467         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 468                                         buffer, buffer_size);
 469
 470 cleanup:
 471         brelse(iloc.bh);
 472         return error;
 473 }
 474
 475 /*
 476  * ext4_xattr_list()
 477  *
 478  * Copy a list of attribute names into the buffer
 479  * provided, or compute the buffer size required.
 480  * Buffer is NULL to compute the size of the buffer required.
 481  *
 482  * Returns a negative error number on failure, or the number of bytes
 483  * used / required on success.
 484  */
 485 static int
 486 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 487 {
 488         int ret, ret2;
 489
 490         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 491         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 492         if (ret < 0)
 493                 goto errout;
 494         if (buffer) {
 495                 buffer += ret;
 496                 buffer_size -= ret;
 497         }
 498         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 499         if (ret < 0)
 500                 goto errout;
 501         ret += ret2;
 502 errout:
 503         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 504         return ret;
 505 }
 506
 507 /*
 508  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 509  * not set, set it.
 510  */
 511 static void ext4_xattr_update_super_block(handle_t *handle,
 512                                           struct super_block *sb)
 513 {
 514         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 515                 return;
 516
 517         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 518                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 519                 ext4_handle_dirty_super(handle, sb);
 520         }
 521 }
 522
 523 /*
 524  * Release the xattr block BH: If the reference count is > 1, decrement
 525  * it; otherwise free the block.
 526  */
 527 static void
 528 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 529                          struct buffer_head *bh)
 530 {
 531         struct mb_cache_entry *ce = NULL;
 532         int error = 0;
 533
 534         ce = mb_cache_entry_get(ext4_xattr_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                 ext4_free_blocks(handle, inode, bh, 0, 1,
 546                                  EXT4_FREE_BLOCKS_METADATA |
 547                                  EXT4_FREE_BLOCKS_FORGET);
 548                 unlock_buffer(bh);
 549         } else {
 550                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 551                 if (ce)
 552                         mb_cache_entry_release(ce);
 553                 unlock_buffer(bh);
 554                 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
 555                 if (IS_SYNC(inode))
 556                         ext4_handle_sync(handle);
 557                 dquot_free_block(inode, 1);
 558                 ea_bdebug(bh, "refcount now=%d; releasing",
 559                           le32_to_cpu(BHDR(bh)->h_refcount));
 560         }
 561 out:
 562         ext4_std_error(inode->i_sb, error);
 563         return;
 564 }
 565
 566 /*
 567  * Find the available free space for EAs. This also returns the total number of
 568  * bytes used by EA entries.
 569  */
 570 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 571                                     size_t *min_offs, void *base, int *total)
 572 {
 573         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 574                 *total += EXT4_XATTR_LEN(last->e_name_len);
 575                 if (!last->e_value_block && last->e_value_size) {
 576                         size_t offs = le16_to_cpu(last->e_value_offs);
 577                         if (offs < *min_offs)
 578                                 *min_offs = offs;
 579                 }
 580         }
 581         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 582 }
 583
 584 struct ext4_xattr_info {
 585         int name_index;
 586         const char *name;
 587         const void *value;
 588         size_t value_len;
 589 };
 590
 591 struct ext4_xattr_search {
 592         struct ext4_xattr_entry *first;
 593         void *base;
 594         void *end;
 595         struct ext4_xattr_entry *here;
 596         int not_found;
 597 };
 598
 599 static int
 600 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 601 {
 602         struct ext4_xattr_entry *last;
 603         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 604
 605         /* Compute min_offs and last. */
 606         last = s->first;
 607         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 608                 if (!last->e_value_block && last->e_value_size) {
 609                         size_t offs = le16_to_cpu(last->e_value_offs);
 610                         if (offs < min_offs)
 611                                 min_offs = offs;
 612                 }
 613         }
 614         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 615         if (!s->not_found) {
 616                 if (!s->here->e_value_block && s->here->e_value_size) {
 617                         size_t size = le32_to_cpu(s->here->e_value_size);
 618                         free += EXT4_XATTR_SIZE(size);
 619                 }
 620                 free += EXT4_XATTR_LEN(name_len);
 621         }
 622         if (i->value) {
 623                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 624                     free < EXT4_XATTR_LEN(name_len) +
 625                            EXT4_XATTR_SIZE(i->value_len))
 626                         return -ENOSPC;
 627         }
 628
 629         if (i->value && s->not_found) {
 630                 /* Insert the new name. */
 631                 size_t size = EXT4_XATTR_LEN(name_len);
 632                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 633                 memmove((void *)s->here + size, s->here, rest);
 634                 memset(s->here, 0, size);
 635                 s->here->e_name_index = i->name_index;
 636                 s->here->e_name_len = name_len;
 637                 memcpy(s->here->e_name, i->name, name_len);
 638         } else {
 639                 if (!s->here->e_value_block && s->here->e_value_size) {
 640                         void *first_val = s->base + min_offs;
 641                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 642                         void *val = s->base + offs;
 643                         size_t size = EXT4_XATTR_SIZE(
 644                                 le32_to_cpu(s->here->e_value_size));
 645
 646                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 647                                 /* The old and the new value have the same
 648                                    size. Just replace. */
 649                                 s->here->e_value_size =
 650                                         cpu_to_le32(i->value_len);
 651                                 memset(val + size - EXT4_XATTR_PAD, 0,
 652                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
 653                                 memcpy(val, i->value, i->value_len);
 654                                 return 0;
 655                         }
 656
 657                         /* Remove the old value. */
 658                         memmove(first_val + size, first_val, val - first_val);
 659                         memset(first_val, 0, size);
 660                         s->here->e_value_size = 0;
 661                         s->here->e_value_offs = 0;
 662                         min_offs += size;
 663
 664                         /* Adjust all value offsets. */
 665                         last = s->first;
 666                         while (!IS_LAST_ENTRY(last)) {
 667                                 size_t o = le16_to_cpu(last->e_value_offs);
 668                                 if (!last->e_value_block &&
 669                                     last->e_value_size && o < offs)
 670                                         last->e_value_offs =
 671                                                 cpu_to_le16(o + size);
 672                                 last = EXT4_XATTR_NEXT(last);
 673                         }
 674                 }
 675                 if (!i->value) {
 676                         /* Remove the old name. */
 677                         size_t size = EXT4_XATTR_LEN(name_len);
 678                         last = ENTRY((void *)last - size);
 679                         memmove(s->here, (void *)s->here + size,
 680                                 (void *)last - (void *)s->here + sizeof(__u32));
 681                         memset(last, 0, size);
 682                 }
 683         }
 684
 685         if (i->value) {
 686                 /* Insert the new value. */
 687                 s->here->e_value_size = cpu_to_le32(i->value_len);
 688                 if (i->value_len) {
 689                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 690                         void *val = s->base + min_offs - size;
 691                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 692                         memset(val + size - EXT4_XATTR_PAD, 0,
 693                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
 694                         memcpy(val, i->value, i->value_len);
 695                 }
 696         }
 697         return 0;
 698 }
 699
 700 struct ext4_xattr_block_find {
 701         struct ext4_xattr_search s;
 702         struct buffer_head *bh;
 703 };
 704
 705 static int
 706 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 707                       struct ext4_xattr_block_find *bs)
 708 {
 709         struct super_block *sb = inode->i_sb;
 710         int error;
 711
 712         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 713                   i->name_index, i->name, i->value, (long)i->value_len);
 714
 715         if (EXT4_I(inode)->i_file_acl) {
 716                 /* The inode already has an extended attribute block. */
 717                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 718                 error = -EIO;
 719                 if (!bs->bh)
 720                         goto cleanup;
 721                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 722                         atomic_read(&(bs->bh->b_count)),
 723                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 724                 if (ext4_xattr_check_block(inode, bs->bh)) {
 725                         EXT4_ERROR_INODE(inode, "bad block %llu",
 726                                          EXT4_I(inode)->i_file_acl);
 727                         error = -EIO;
 728                         goto cleanup;
 729                 }
 730                 /* Find the named attribute. */
 731                 bs->s.base = BHDR(bs->bh);
 732                 bs->s.first = BFIRST(bs->bh);
 733                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 734                 bs->s.here = bs->s.first;
 735                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 736                                               i->name, bs->bh->b_size, 1);
 737                 if (error && error != -ENODATA)
 738                         goto cleanup;
 739                 bs->s.not_found = error;
 740         }
 741         error = 0;
 742
 743 cleanup:
 744         return error;
 745 }
 746
 747 static int
 748 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 749                      struct ext4_xattr_info *i,
 750                      struct ext4_xattr_block_find *bs)
 751 {
 752         struct super_block *sb = inode->i_sb;
 753         struct buffer_head *new_bh = NULL;
 754         struct ext4_xattr_search *s = &bs->s;
 755         struct mb_cache_entry *ce = NULL;
 756         int error = 0;
 757
 758 #define header(x) ((struct ext4_xattr_header *)(x))
 759
 760         if (i->value && i->value_len > sb->s_blocksize)
 761                 return -ENOSPC;
 762         if (s->base) {
 763                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 764                                         bs->bh->b_blocknr);
 765                 error = ext4_journal_get_write_access(handle, bs->bh);
 766                 if (error)
 767                         goto cleanup;
 768                 lock_buffer(bs->bh);
 769
 770                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 771                         if (ce) {
 772                                 mb_cache_entry_free(ce);
 773                                 ce = NULL;
 774                         }
 775                         ea_bdebug(bs->bh, "modifying in-place");
 776                         error = ext4_xattr_set_entry(i, s);
 777                         if (!error) {
 778                                 if (!IS_LAST_ENTRY(s->first))
 779                                         ext4_xattr_rehash(header(s->base),
 780                                                           s->here);
 781                                 ext4_xattr_cache_insert(bs->bh);
 782                         }
 783                         unlock_buffer(bs->bh);
 784                         if (error == -EIO)
 785                                 goto bad_block;
 786                         if (!error)
 787                                 error = ext4_handle_dirty_xattr_block(handle,
 788                                                                       inode,
 789                                                                       bs->bh);
 790                         if (error)
 791                                 goto cleanup;
 792                         goto inserted;
 793                 } else {
 794                         int offset = (char *)s->here - bs->bh->b_data;
 795
 796                         unlock_buffer(bs->bh);
 797                         ext4_handle_release_buffer(handle, bs->bh);
 798                         if (ce) {
 799                                 mb_cache_entry_release(ce);
 800                                 ce = NULL;
 801                         }
 802                         ea_bdebug(bs->bh, "cloning");
 803                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 804                         error = -ENOMEM;
 805                         if (s->base == NULL)
 806                                 goto cleanup;
 807                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 808                         s->first = ENTRY(header(s->base)+1);
 809                         header(s->base)->h_refcount = cpu_to_le32(1);
 810                         s->here = ENTRY(s->base + offset);
 811                         s->end = s->base + bs->bh->b_size;
 812                 }
 813         } else {
 814                 /* Allocate a buffer where we construct the new block. */
 815                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 816                 /* assert(header == s->base) */
 817                 error = -ENOMEM;
 818                 if (s->base == NULL)
 819                         goto cleanup;
 820                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 821                 header(s->base)->h_blocks = cpu_to_le32(1);
 822                 header(s->base)->h_refcount = cpu_to_le32(1);
 823                 s->first = ENTRY(header(s->base)+1);
 824                 s->here = ENTRY(header(s->base)+1);
 825                 s->end = s->base + sb->s_blocksize;
 826         }
 827
 828         error = ext4_xattr_set_entry(i, s);
 829         if (error == -EIO)
 830                 goto bad_block;
 831         if (error)
 832                 goto cleanup;
 833         if (!IS_LAST_ENTRY(s->first))
 834                 ext4_xattr_rehash(header(s->base), s->here);
 835
 836 inserted:
 837         if (!IS_LAST_ENTRY(s->first)) {
 838                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 839                 if (new_bh) {
 840                         /* We found an identical block in the cache. */
 841                         if (new_bh == bs->bh)
 842                                 ea_bdebug(new_bh, "keeping");
 843                         else {
 844                                 /* The old block is released after updating
 845                                    the inode. */
 846                                 error = dquot_alloc_block(inode, 1);
 847                                 if (error)
 848                                         goto cleanup;
 849                                 error = ext4_journal_get_write_access(handle,
 850                                                                       new_bh);
 851                                 if (error)
 852                                         goto cleanup_dquot;
 853                                 lock_buffer(new_bh);
 854                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 855                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 856                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 857                                 unlock_buffer(new_bh);
 858                                 error = ext4_handle_dirty_xattr_block(handle,
 859                                                                       inode,
 860                                                                       new_bh);
 861                                 if (error)
 862                                         goto cleanup_dquot;
 863                         }
 864                         mb_cache_entry_release(ce);
 865                         ce = NULL;
 866                 } else if (bs->bh && s->base == bs->bh->b_data) {
 867                         /* We were modifying this block in-place. */
 868                         ea_bdebug(bs->bh, "keeping this block");
 869                         new_bh = bs->bh;
 870                         get_bh(new_bh);
 871                 } else {
 872                         /* We need to allocate a new block */
 873                         ext4_fsblk_t goal, block;
 874
 875                         goal = ext4_group_first_block_no(sb,
 876                                                 EXT4_I(inode)->i_block_group);
 877
 878                         /* non-extent files can't have physical blocks past 2^32 */
 879                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 880                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 881
 882                         /*
 883                          * take i_data_sem because we will test
 884                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 885                          */
 886                         down_read((&EXT4_I(inode)->i_data_sem));
 887                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 888                                                      NULL, &error);
 889                         up_read((&EXT4_I(inode)->i_data_sem));
 890                         if (error)
 891                                 goto cleanup;
 892
 893                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 894                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 895
 896                         ea_idebug(inode, "creating block %llu",
 897                                   (unsigned long long)block);
 898
 899                         new_bh = sb_getblk(sb, block);
 900                         if (!new_bh) {
 901 getblk_failed:
 902                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 903                                                  EXT4_FREE_BLOCKS_METADATA);
 904                                 error = -EIO;
 905                                 goto cleanup;
 906                         }
 907                         lock_buffer(new_bh);
 908                         error = ext4_journal_get_create_access(handle, new_bh);
 909                         if (error) {
 910                                 unlock_buffer(new_bh);
 911                                 goto getblk_failed;
 912                         }
 913                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 914                         set_buffer_uptodate(new_bh);
 915                         unlock_buffer(new_bh);
 916                         ext4_xattr_cache_insert(new_bh);
 917                         error = ext4_handle_dirty_xattr_block(handle,
 918                                                               inode, new_bh);
 919                         if (error)
 920                                 goto cleanup;
 921                 }
 922         }
 923
 924         /* Update the inode. */
 925         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 926
 927         /* Drop the previous xattr block. */
 928         if (bs->bh && bs->bh != new_bh)
 929                 ext4_xattr_release_block(handle, inode, bs->bh);
 930         error = 0;
 931
 932 cleanup:
 933         if (ce)
 934                 mb_cache_entry_release(ce);
 935         brelse(new_bh);
 936         if (!(bs->bh && s->base == bs->bh->b_data))
 937                 kfree(s->base);
 938
 939         return error;
 940
 941 cleanup_dquot:
 942         dquot_free_block(inode, 1);
 943         goto cleanup;
 944
 945 bad_block:
 946         EXT4_ERROR_INODE(inode, "bad block %llu",
 947                          EXT4_I(inode)->i_file_acl);
 948         goto cleanup;
 949
 950 #undef header
 951 }
 952
 953 struct ext4_xattr_ibody_find {
 954         struct ext4_xattr_search s;
 955         struct ext4_iloc iloc;
 956 };
 957
 958 static int
 959 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 960                       struct ext4_xattr_ibody_find *is)
 961 {
 962         struct ext4_xattr_ibody_header *header;
 963         struct ext4_inode *raw_inode;
 964         int error;
 965
 966         if (EXT4_I(inode)->i_extra_isize == 0)
 967                 return 0;
 968         raw_inode = ext4_raw_inode(&is->iloc);
 969         header = IHDR(inode, raw_inode);
 970         is->s.base = is->s.first = IFIRST(header);
 971         is->s.here = is->s.first;
 972         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 973         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 974                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 975                 if (error)
 976                         return error;
 977                 /* Find the named attribute. */
 978                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 979                                               i->name, is->s.end -
 980                                               (void *)is->s.base, 0);
 981                 if (error && error != -ENODATA)
 982                         return error;
 983                 is->s.not_found = error;
 984         }
 985         return 0;
 986 }
 987
 988 static int
 989 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 990                      struct ext4_xattr_info *i,
 991                      struct ext4_xattr_ibody_find *is)
 992 {
 993         struct ext4_xattr_ibody_header *header;
 994         struct ext4_xattr_search *s = &is->s;
 995         int error;
 996
 997         if (EXT4_I(inode)->i_extra_isize == 0)
 998                 return -ENOSPC;
 999         error = ext4_xattr_set_entry(i, s);
1000         if (error)
1001                 return error;
1002         header = IHDR(inode, ext4_raw_inode(&is->iloc));
1003         if (!IS_LAST_ENTRY(s->first)) {
1004                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1005                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1006         } else {
1007                 header->h_magic = cpu_to_le32(0);
1008                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1009         }
1010         return 0;
1011 }
1012
1013 /*
1014  * ext4_xattr_set_handle()
1015  *
1016  * Create, replace or remove an extended attribute for this inode.  Value
1017  * is NULL to remove an existing extended attribute, and non-NULL to
1018  * either replace an existing extended attribute, or create a new extended
1019  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1020  * specify that an extended attribute must exist and must not exist
1021  * previous to the call, respectively.
1022  *
1023  * Returns 0, or a negative error number on failure.
1024  */
1025 int
1026 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1027                       const char *name, const void *value, size_t value_len,
1028                       int flags)
1029 {
1030         struct ext4_xattr_info i = {
1031                 .name_index = name_index,
1032                 .name = name,
1033                 .value = value,
1034                 .value_len = value_len,
1035
1036         };
1037         struct ext4_xattr_ibody_find is = {
1038                 .s = { .not_found = -ENODATA, },
1039         };
1040         struct ext4_xattr_block_find bs = {
1041                 .s = { .not_found = -ENODATA, },
1042         };
1043         unsigned long no_expand;
1044         int error;
1045
1046         if (!name)
1047                 return -EINVAL;
1048         if (strlen(name) > 255)
1049                 return -ERANGE;
1050         down_write(&EXT4_I(inode)->xattr_sem);
1051         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1052         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1053
1054         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1055         if (error)
1056                 goto cleanup;
1057
1058         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1059                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1060                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1061                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1062         }
1063
1064         error = ext4_xattr_ibody_find(inode, &i, &is);
1065         if (error)
1066                 goto cleanup;
1067         if (is.s.not_found)
1068                 error = ext4_xattr_block_find(inode, &i, &bs);
1069         if (error)
1070                 goto cleanup;
1071         if (is.s.not_found && bs.s.not_found) {
1072                 error = -ENODATA;
1073                 if (flags & XATTR_REPLACE)
1074                         goto cleanup;
1075                 error = 0;
1076                 if (!value)
1077                         goto cleanup;
1078         } else {
1079                 error = -EEXIST;
1080                 if (flags & XATTR_CREATE)
1081                         goto cleanup;
1082         }
1083         if (!value) {
1084                 if (!is.s.not_found)
1085                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1086                 else if (!bs.s.not_found)
1087                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1088         } else {
1089                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1090                 if (!error && !bs.s.not_found) {
1091                         i.value = NULL;
1092                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1093                 } else if (error == -ENOSPC) {
1094                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1095                                 error = ext4_xattr_block_find(inode, &i, &bs);
1096                                 if (error)
1097                                         goto cleanup;
1098                         }
1099                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1100                         if (error)
1101                                 goto cleanup;
1102                         if (!is.s.not_found) {
1103                                 i.value = NULL;
1104                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1105                                                              &is);
1106                         }
1107                 }
1108         }
1109         if (!error) {
1110                 ext4_xattr_update_super_block(handle, inode->i_sb);
1111                 inode->i_ctime = ext4_current_time(inode);
1112                 if (!value)
1113                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1114                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1115                 /*
1116                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1117                  * error != 0.
1118                  */
1119                 is.iloc.bh = NULL;
1120                 if (IS_SYNC(inode))
1121                         ext4_handle_sync(handle);
1122         }
1123
1124 cleanup:
1125         brelse(is.iloc.bh);
1126         brelse(bs.bh);
1127         if (no_expand == 0)
1128                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1129         up_write(&EXT4_I(inode)->xattr_sem);
1130         return error;
1131 }
1132
1133 /*
1134  * ext4_xattr_set()
1135  *
1136  * Like ext4_xattr_set_handle, but start from an inode. This extended
1137  * attribute modification is a filesystem transaction by itself.
1138  *
1139  * Returns 0, or a negative error number on failure.
1140  */
1141 int
1142 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1143                const void *value, size_t value_len, int flags)
1144 {
1145         handle_t *handle;
1146         int error, retries = 0;
1147
1148 retry:
1149         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1150         if (IS_ERR(handle)) {
1151                 error = PTR_ERR(handle);
1152         } else {
1153                 int error2;
1154
1155                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1156                                               value, value_len, flags);
1157                 error2 = ext4_journal_stop(handle);
1158                 if (error == -ENOSPC &&
1159                     ext4_should_retry_alloc(inode->i_sb, &retries))
1160                         goto retry;
1161                 if (error == 0)
1162                         error = error2;
1163         }
1164
1165         return error;
1166 }
1167
1168 /*
1169  * Shift the EA entries in the inode to create space for the increased
1170  * i_extra_isize.
1171  */
1172 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1173                                      int value_offs_shift, void *to,
1174                                      void *from, size_t n, int blocksize)
1175 {
1176         struct ext4_xattr_entry *last = entry;
1177         int new_offs;
1178
1179         /* Adjust the value offsets of the entries */
1180         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1181                 if (!last->e_value_block && last->e_value_size) {
1182                         new_offs = le16_to_cpu(last->e_value_offs) +
1183                                                         value_offs_shift;
1184                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1185                                  > blocksize);
1186                         last->e_value_offs = cpu_to_le16(new_offs);
1187                 }
1188         }
1189         /* Shift the entries by n bytes */
1190         memmove(to, from, n);
1191 }
1192
1193 /*
1194  * Expand an inode by new_extra_isize bytes when EAs are present.
1195  * Returns 0 on success or negative error number on failure.
1196  */
1197 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1198                                struct ext4_inode *raw_inode, handle_t *handle)
1199 {
1200         struct ext4_xattr_ibody_header *header;
1201         struct ext4_xattr_entry *entry, *last, *first;
1202         struct buffer_head *bh = NULL;
1203         struct ext4_xattr_ibody_find *is = NULL;
1204         struct ext4_xattr_block_find *bs = NULL;
1205         char *buffer = NULL, *b_entry_name = NULL;
1206         size_t min_offs, free;
1207         int total_ino, total_blk;
1208         void *base, *start, *end;
1209         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1210         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1211
1212         down_write(&EXT4_I(inode)->xattr_sem);
1213 retry:
1214         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1215                 up_write(&EXT4_I(inode)->xattr_sem);
1216                 return 0;
1217         }
1218
1219         header = IHDR(inode, raw_inode);
1220         entry = IFIRST(header);
1221
1222         /*
1223          * Check if enough free space is available in the inode to shift the
1224          * entries ahead by new_extra_isize.
1225          */
1226
1227         base = start = entry;
1228         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1229         min_offs = end - base;
1230         last = entry;
1231         total_ino = sizeof(struct ext4_xattr_ibody_header);
1232
1233         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1234         if (free >= new_extra_isize) {
1235                 entry = IFIRST(header);
1236                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1237                                 - new_extra_isize, (void *)raw_inode +
1238                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1239                                 (void *)header, total_ino,
1240                                 inode->i_sb->s_blocksize);
1241                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1242                 error = 0;
1243                 goto cleanup;
1244         }
1245
1246         /*
1247          * Enough free space isn't available in the inode, check if
1248          * EA block can hold new_extra_isize bytes.
1249          */
1250         if (EXT4_I(inode)->i_file_acl) {
1251                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1252                 error = -EIO;
1253                 if (!bh)
1254                         goto cleanup;
1255                 if (ext4_xattr_check_block(inode, bh)) {
1256                         EXT4_ERROR_INODE(inode, "bad block %llu",
1257                                          EXT4_I(inode)->i_file_acl);
1258                         error = -EIO;
1259                         goto cleanup;
1260                 }
1261                 base = BHDR(bh);
1262                 first = BFIRST(bh);
1263                 end = bh->b_data + bh->b_size;
1264                 min_offs = end - base;
1265                 free = ext4_xattr_free_space(first, &min_offs, base,
1266                                              &total_blk);
1267                 if (free < new_extra_isize) {
1268                         if (!tried_min_extra_isize && s_min_extra_isize) {
1269                                 tried_min_extra_isize++;
1270                                 new_extra_isize = s_min_extra_isize;
1271                                 brelse(bh);
1272                                 goto retry;
1273                         }
1274                         error = -1;
1275                         goto cleanup;
1276                 }
1277         } else {
1278                 free = inode->i_sb->s_blocksize;
1279         }
1280
1281         while (new_extra_isize > 0) {
1282                 size_t offs, size, entry_size;
1283                 struct ext4_xattr_entry *small_entry = NULL;
1284                 struct ext4_xattr_info i = {
1285                         .value = NULL,
1286                         .value_len = 0,
1287                 };
1288                 unsigned int total_size;  /* EA entry size + value size */
1289                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1290                 unsigned int min_total_size = ~0U;
1291
1292                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1293                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1294                 if (!is || !bs) {
1295                         error = -ENOMEM;
1296                         goto cleanup;
1297                 }
1298
1299                 is->s.not_found = -ENODATA;
1300                 bs->s.not_found = -ENODATA;
1301                 is->iloc.bh = NULL;
1302                 bs->bh = NULL;
1303
1304                 last = IFIRST(header);
1305                 /* Find the entry best suited to be pushed into EA block */
1306                 entry = NULL;
1307                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1308                         total_size =
1309                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1310                                         EXT4_XATTR_LEN(last->e_name_len);
1311                         if (total_size <= free && total_size < min_total_size) {
1312                                 if (total_size < new_extra_isize) {
1313                                         small_entry = last;
1314                                 } else {
1315                                         entry = last;
1316                                         min_total_size = total_size;
1317                                 }
1318                         }
1319                 }
1320
1321                 if (entry == NULL) {
1322                         if (small_entry) {
1323                                 entry = small_entry;
1324                         } else {
1325                                 if (!tried_min_extra_isize &&
1326                                     s_min_extra_isize) {
1327                                         tried_min_extra_isize++;
1328                                         new_extra_isize = s_min_extra_isize;
1329                                         goto retry;
1330                                 }
1331                                 error = -1;
1332                                 goto cleanup;
1333                         }
1334                 }
1335                 offs = le16_to_cpu(entry->e_value_offs);
1336                 size = le32_to_cpu(entry->e_value_size);
1337                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1338                 i.name_index = entry->e_name_index,
1339                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1340                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1341                 if (!buffer || !b_entry_name) {
1342                         error = -ENOMEM;
1343                         goto cleanup;
1344                 }
1345                 /* Save the entry name and the entry value */
1346                 memcpy(buffer, (void *)IFIRST(header) + offs,
1347                        EXT4_XATTR_SIZE(size));
1348                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1349                 b_entry_name[entry->e_name_len] = '\0';
1350                 i.name = b_entry_name;
1351
1352                 error = ext4_get_inode_loc(inode, &is->iloc);
1353                 if (error)
1354                         goto cleanup;
1355
1356                 error = ext4_xattr_ibody_find(inode, &i, is);
1357                 if (error)
1358                         goto cleanup;
1359
1360                 /* Remove the chosen entry from the inode */
1361                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1362                 if (error)
1363                         goto cleanup;
1364
1365                 entry = IFIRST(header);
1366                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1367                         shift_bytes = new_extra_isize;
1368                 else
1369                         shift_bytes = entry_size + size;
1370                 /* Adjust the offsets and shift the remaining entries ahead */
1371                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1372                         shift_bytes, (void *)raw_inode +
1373                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1374                         (void *)header, total_ino - entry_size,
1375                         inode->i_sb->s_blocksize);
1376
1377                 extra_isize += shift_bytes;
1378                 new_extra_isize -= shift_bytes;
1379                 EXT4_I(inode)->i_extra_isize = extra_isize;
1380
1381                 i.name = b_entry_name;
1382                 i.value = buffer;
1383                 i.value_len = size;
1384                 error = ext4_xattr_block_find(inode, &i, bs);
1385                 if (error)
1386                         goto cleanup;
1387
1388                 /* Add entry which was removed from the inode into the block */
1389                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1390                 if (error)
1391                         goto cleanup;
1392                 kfree(b_entry_name);
1393                 kfree(buffer);
1394                 b_entry_name = NULL;
1395                 buffer = NULL;
1396                 brelse(is->iloc.bh);
1397                 kfree(is);
1398                 kfree(bs);
1399         }
1400         brelse(bh);
1401         up_write(&EXT4_I(inode)->xattr_sem);
1402         return 0;
1403
1404 cleanup:
1405         kfree(b_entry_name);
1406         kfree(buffer);
1407         if (is)
1408                 brelse(is->iloc.bh);
1409         kfree(is);
1410         kfree(bs);
1411         brelse(bh);
1412         up_write(&EXT4_I(inode)->xattr_sem);
1413         return error;
1414 }
1415
1416
1417
1418 /*
1419  * ext4_xattr_delete_inode()
1420  *
1421  * Free extended attribute resources associated with this inode. This
1422  * is called immediately before an inode is freed. We have exclusive
1423  * access to the inode.
1424  */
1425 void
1426 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1427 {
1428         struct buffer_head *bh = NULL;
1429
1430         if (!EXT4_I(inode)->i_file_acl)
1431                 goto cleanup;
1432         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1433         if (!bh) {
1434                 EXT4_ERROR_INODE(inode, "block %llu read error",
1435                                  EXT4_I(inode)->i_file_acl);
1436                 goto cleanup;
1437         }
1438         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1439             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1440                 EXT4_ERROR_INODE(inode, "bad block %llu",
1441                                  EXT4_I(inode)->i_file_acl);
1442                 goto cleanup;
1443         }
1444         ext4_xattr_release_block(handle, inode, bh);
1445         EXT4_I(inode)->i_file_acl = 0;
1446
1447 cleanup:
1448         brelse(bh);
1449 }
1450
1451 /*
1452  * ext4_xattr_put_super()
1453  *
1454  * This is called when a file system is unmounted.
1455  */
1456 void
1457 ext4_xattr_put_super(struct super_block *sb)
1458 {
1459         mb_cache_shrink(sb->s_bdev);
1460 }
1461
1462 /*
1463  * ext4_xattr_cache_insert()
1464  *
1465  * Create a new entry in the extended attribute cache, and insert
1466  * it unless such an entry is already in the cache.
1467  *
1468  * Returns 0, or a negative error number on failure.
1469  */
1470 static void
1471 ext4_xattr_cache_insert(struct buffer_head *bh)
1472 {
1473         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1474         struct mb_cache_entry *ce;
1475         int error;
1476
1477         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1478         if (!ce) {
1479                 ea_bdebug(bh, "out of memory");
1480                 return;
1481         }
1482         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1483         if (error) {
1484                 mb_cache_entry_free(ce);
1485                 if (error == -EBUSY) {
1486                         ea_bdebug(bh, "already in cache");
1487                         error = 0;
1488                 }
1489         } else {
1490                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1491                 mb_cache_entry_release(ce);
1492         }
1493 }
1494
1495 /*
1496  * ext4_xattr_cmp()
1497  *
1498  * Compare two extended attribute blocks for equality.
1499  *
1500  * Returns 0 if the blocks are equal, 1 if they differ, and
1501  * a negative error number on errors.
1502  */
1503 static int
1504 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1505                struct ext4_xattr_header *header2)
1506 {
1507         struct ext4_xattr_entry *entry1, *entry2;
1508
1509         entry1 = ENTRY(header1+1);
1510         entry2 = ENTRY(header2+1);
1511         while (!IS_LAST_ENTRY(entry1)) {
1512                 if (IS_LAST_ENTRY(entry2))
1513                         return 1;
1514                 if (entry1->e_hash != entry2->e_hash ||
1515                     entry1->e_name_index != entry2->e_name_index ||
1516                     entry1->e_name_len != entry2->e_name_len ||
1517                     entry1->e_value_size != entry2->e_value_size ||
1518                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1519                         return 1;
1520                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1521                         return -EIO;
1522                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1523                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1524                            le32_to_cpu(entry1->e_value_size)))
1525                         return 1;
1526
1527                 entry1 = EXT4_XATTR_NEXT(entry1);
1528                 entry2 = EXT4_XATTR_NEXT(entry2);
1529         }
1530         if (!IS_LAST_ENTRY(entry2))
1531                 return 1;
1532         return 0;
1533 }
1534
1535 /*
1536  * ext4_xattr_cache_find()
1537  *
1538  * Find an identical extended attribute block.
1539  *
1540  * Returns a pointer to the block found, or NULL if such a block was
1541  * not found or an error occurred.
1542  */
1543 static struct buffer_head *
1544 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1545                       struct mb_cache_entry **pce)
1546 {
1547         __u32 hash = le32_to_cpu(header->h_hash);
1548         struct mb_cache_entry *ce;
1549
1550         if (!header->h_hash)
1551                 return NULL;  /* never share */
1552         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1553 again:
1554         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1555                                        hash);
1556         while (ce) {
1557                 struct buffer_head *bh;
1558
1559                 if (IS_ERR(ce)) {
1560                         if (PTR_ERR(ce) == -EAGAIN)
1561                                 goto again;
1562                         break;
1563                 }
1564                 bh = sb_bread(inode->i_sb, ce->e_block);
1565                 if (!bh) {
1566                         EXT4_ERROR_INODE(inode, "block %lu read error",
1567                                          (unsigned long) ce->e_block);
1568                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1569                                 EXT4_XATTR_REFCOUNT_MAX) {
1570                         ea_idebug(inode, "block %lu refcount %d>=%d",
1571                                   (unsigned long) ce->e_block,
1572                                   le32_to_cpu(BHDR(bh)->h_refcount),
1573                                           EXT4_XATTR_REFCOUNT_MAX);
1574                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1575                         *pce = ce;
1576                         return bh;
1577                 }
1578                 brelse(bh);
1579                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1580         }
1581         return NULL;
1582 }
1583
1584 #define NAME_HASH_SHIFT 5
1585 #define VALUE_HASH_SHIFT 16
1586
1587 /*
1588  * ext4_xattr_hash_entry()
1589  *
1590  * Compute the hash of an extended attribute.
1591  */
1592 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1593                                          struct ext4_xattr_entry *entry)
1594 {
1595         __u32 hash = 0;
1596         char *name = entry->e_name;
1597         int n;
1598
1599         for (n = 0; n < entry->e_name_len; n++) {
1600                 hash = (hash << NAME_HASH_SHIFT) ^
1601                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1602                        *name++;
1603         }
1604
1605         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1606                 __le32 *value = (__le32 *)((char *)header +
1607                         le16_to_cpu(entry->e_value_offs));
1608                 for (n = (le32_to_cpu(entry->e_value_size) +
1609                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1610                         hash = (hash << VALUE_HASH_SHIFT) ^
1611                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1612                                le32_to_cpu(*value++);
1613                 }
1614         }
1615         entry->e_hash = cpu_to_le32(hash);
1616 }
1617
1618 #undef NAME_HASH_SHIFT
1619 #undef VALUE_HASH_SHIFT
1620
1621 #define BLOCK_HASH_SHIFT 16
1622
1623 /*
1624  * ext4_xattr_rehash()
1625  *
1626  * Re-compute the extended attribute hash value after an entry has changed.
1627  */
1628 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1629                               struct ext4_xattr_entry *entry)
1630 {
1631         struct ext4_xattr_entry *here;
1632         __u32 hash = 0;
1633
1634         ext4_xattr_hash_entry(header, entry);
1635         here = ENTRY(header+1);
1636         while (!IS_LAST_ENTRY(here)) {
1637                 if (!here->e_hash) {
1638                         /* Block is not shared if an entry's hash value == 0 */
1639                         hash = 0;
1640                         break;
1641                 }
1642                 hash = (hash << BLOCK_HASH_SHIFT) ^
1643                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1644                        le32_to_cpu(here->e_hash);
1645                 here = EXT4_XATTR_NEXT(here);
1646         }
1647         header->h_hash = cpu_to_le32(hash);
1648 }
1649
1650 #undef BLOCK_HASH_SHIFT
1651
1652 int __init
1653 ext4_init_xattr(void)
1654 {
1655         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1656         if (!ext4_xattr_cache)
1657                 return -ENOMEM;
1658         return 0;
1659 }
1660
1661 void
1662 ext4_exit_xattr(void)
1663 {
1664         if (ext4_xattr_cache)
1665                 mb_cache_destroy(ext4_xattr_cache);
1666         ext4_xattr_cache = NULL;
1667 }