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/ext4_jbd2.h>
  57 #include <linux/ext4_fs.h>
  58 #include <linux/mbcache.h>
  59 #include <linux/quotaops.h>
  60 #include <linux/rwsem.h>
  61 #include "xattr.h"
  62 #include "acl.h"
  63
  64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
  65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
  66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
  67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
  68
  69 #ifdef EXT4_XATTR_DEBUG
  70 # define ea_idebug(inode, f...) do { \
  71                 printk(KERN_DEBUG "inode %s:%lu: ", \
  72                         inode->i_sb->s_id, inode->i_ino); \
  73                 printk(f); \
  74                 printk("\n"); \
  75         } while (0)
  76 # define ea_bdebug(bh, f...) do { \
  77                 char b[BDEVNAME_SIZE]; \
  78                 printk(KERN_DEBUG "block %s:%lu: ", \
  79                         bdevname(bh->b_bdev, b), \
  80                         (unsigned long) bh->b_blocknr); \
  81                 printk(f); \
  82                 printk("\n"); \
  83         } while (0)
  84 #else
  85 # define ea_idebug(f...)
  86 # define ea_bdebug(f...)
  87 #endif
  88
  89 static void ext4_xattr_cache_insert(struct buffer_head *);
  90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  91                                                  struct ext4_xattr_header *,
  92                                                  struct mb_cache_entry **);
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  94                               struct ext4_xattr_entry *);
  95
  96 static struct mb_cache *ext4_xattr_cache;
  97
  98 static struct xattr_handler *ext4_xattr_handler_map[] = {
  99         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
 100 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
 101         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
 102         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
 103 #endif
 104         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 105 #ifdef CONFIG_EXT4DEV_FS_SECURITY
 106         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 107 #endif
 108 };
 109
 110 struct xattr_handler *ext4_xattr_handlers[] = {
 111         &ext4_xattr_user_handler,
 112         &ext4_xattr_trusted_handler,
 113 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
 114         &ext4_xattr_acl_access_handler,
 115         &ext4_xattr_acl_default_handler,
 116 #endif
 117 #ifdef CONFIG_EXT4DEV_FS_SECURITY
 118         &ext4_xattr_security_handler,
 119 #endif
 120         NULL
 121 };
 122
 123 static inline struct xattr_handler *
 124 ext4_xattr_handler(int name_index)
 125 {
 126         struct xattr_handler *handler = NULL;
 127
 128         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 129                 handler = ext4_xattr_handler_map[name_index];
 130         return handler;
 131 }
 132
 133 /*
 134  * Inode operation listxattr()
 135  *
 136  * dentry->d_inode->i_mutex: don't care
 137  */
 138 ssize_t
 139 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 140 {
 141         return ext4_xattr_list(dentry->d_inode, buffer, size);
 142 }
 143
 144 static int
 145 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 146 {
 147         while (!IS_LAST_ENTRY(entry)) {
 148                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
 149                 if ((void *)next >= end)
 150                         return -EIO;
 151                 entry = next;
 152         }
 153         return 0;
 154 }
 155
 156 static inline int
 157 ext4_xattr_check_block(struct buffer_head *bh)
 158 {
 159         int error;
 160
 161         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 162             BHDR(bh)->h_blocks != cpu_to_le32(1))
 163                 return -EIO;
 164         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 165         return error;
 166 }
 167
 168 static inline int
 169 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 170 {
 171         size_t value_size = le32_to_cpu(entry->e_value_size);
 172
 173         if (entry->e_value_block != 0 || value_size > size ||
 174             le16_to_cpu(entry->e_value_offs) + value_size > size)
 175                 return -EIO;
 176         return 0;
 177 }
 178
 179 static int
 180 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 181                       const char *name, size_t size, int sorted)
 182 {
 183         struct ext4_xattr_entry *entry;
 184         size_t name_len;
 185         int cmp = 1;
 186
 187         if (name == NULL)
 188                 return -EINVAL;
 189         name_len = strlen(name);
 190         entry = *pentry;
 191         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 192                 cmp = name_index - entry->e_name_index;
 193                 if (!cmp)
 194                         cmp = name_len - entry->e_name_len;
 195                 if (!cmp)
 196                         cmp = memcmp(name, entry->e_name, name_len);
 197                 if (cmp <= 0 && (sorted || cmp == 0))
 198                         break;
 199         }
 200         *pentry = entry;
 201         if (!cmp && ext4_xattr_check_entry(entry, size))
 202                         return -EIO;
 203         return cmp ? -ENODATA : 0;
 204 }
 205
 206 static int
 207 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 208                      void *buffer, size_t buffer_size)
 209 {
 210         struct buffer_head *bh = NULL;
 211         struct ext4_xattr_entry *entry;
 212         size_t size;
 213         int error;
 214
 215         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 216                   name_index, name, buffer, (long)buffer_size);
 217
 218         error = -ENODATA;
 219         if (!EXT4_I(inode)->i_file_acl)
 220                 goto cleanup;
 221         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
 222         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 223         if (!bh)
 224                 goto cleanup;
 225         ea_bdebug(bh, "b_count=%d, refcount=%d",
 226                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 227         if (ext4_xattr_check_block(bh)) {
 228 bad_block:      ext4_error(inode->i_sb, __FUNCTION__,
 229                            "inode %lu: bad block %llu", inode->i_ino,
 230                            EXT4_I(inode)->i_file_acl);
 231                 error = -EIO;
 232                 goto cleanup;
 233         }
 234         ext4_xattr_cache_insert(bh);
 235         entry = BFIRST(bh);
 236         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 237         if (error == -EIO)
 238                 goto bad_block;
 239         if (error)
 240                 goto cleanup;
 241         size = le32_to_cpu(entry->e_value_size);
 242         if (buffer) {
 243                 error = -ERANGE;
 244                 if (size > buffer_size)
 245                         goto cleanup;
 246                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 247                        size);
 248         }
 249         error = size;
 250
 251 cleanup:
 252         brelse(bh);
 253         return error;
 254 }
 255
 256 static int
 257 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 258                      void *buffer, size_t buffer_size)
 259 {
 260         struct ext4_xattr_ibody_header *header;
 261         struct ext4_xattr_entry *entry;
 262         struct ext4_inode *raw_inode;
 263         struct ext4_iloc iloc;
 264         size_t size;
 265         void *end;
 266         int error;
 267
 268         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
 269                 return -ENODATA;
 270         error = ext4_get_inode_loc(inode, &iloc);
 271         if (error)
 272                 return error;
 273         raw_inode = ext4_raw_inode(&iloc);
 274         header = IHDR(inode, raw_inode);
 275         entry = IFIRST(header);
 276         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 277         error = ext4_xattr_check_names(entry, end);
 278         if (error)
 279                 goto cleanup;
 280         error = ext4_xattr_find_entry(&entry, name_index, name,
 281                                       end - (void *)entry, 0);
 282         if (error)
 283                 goto cleanup;
 284         size = le32_to_cpu(entry->e_value_size);
 285         if (buffer) {
 286                 error = -ERANGE;
 287                 if (size > buffer_size)
 288                         goto cleanup;
 289                 memcpy(buffer, (void *)IFIRST(header) +
 290                        le16_to_cpu(entry->e_value_offs), size);
 291         }
 292         error = size;
 293
 294 cleanup:
 295         brelse(iloc.bh);
 296         return error;
 297 }
 298
 299 /*
 300  * ext4_xattr_get()
 301  *
 302  * Copy an extended attribute into the buffer
 303  * provided, or compute the buffer size required.
 304  * Buffer is NULL to compute the size of the buffer required.
 305  *
 306  * Returns a negative error number on failure, or the number of bytes
 307  * used / required on success.
 308  */
 309 int
 310 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 311                void *buffer, size_t buffer_size)
 312 {
 313         int error;
 314
 315         down_read(&EXT4_I(inode)->xattr_sem);
 316         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 317                                      buffer_size);
 318         if (error == -ENODATA)
 319                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 320                                              buffer_size);
 321         up_read(&EXT4_I(inode)->xattr_sem);
 322         return error;
 323 }
 324
 325 static int
 326 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
 327                         char *buffer, size_t buffer_size)
 328 {
 329         size_t rest = buffer_size;
 330
 331         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 332                 struct xattr_handler *handler =
 333                         ext4_xattr_handler(entry->e_name_index);
 334
 335                 if (handler) {
 336                         size_t size = handler->list(inode, buffer, rest,
 337                                                     entry->e_name,
 338                                                     entry->e_name_len);
 339                         if (buffer) {
 340                                 if (size > rest)
 341                                         return -ERANGE;
 342                                 buffer += size;
 343                         }
 344                         rest -= size;
 345                 }
 346         }
 347         return buffer_size - rest;
 348 }
 349
 350 static int
 351 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
 352 {
 353         struct buffer_head *bh = NULL;
 354         int error;
 355
 356         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 357                   buffer, (long)buffer_size);
 358
 359         error = 0;
 360         if (!EXT4_I(inode)->i_file_acl)
 361                 goto cleanup;
 362         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
 363         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 364         error = -EIO;
 365         if (!bh)
 366                 goto cleanup;
 367         ea_bdebug(bh, "b_count=%d, refcount=%d",
 368                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 369         if (ext4_xattr_check_block(bh)) {
 370                 ext4_error(inode->i_sb, __FUNCTION__,
 371                            "inode %lu: bad block %llu", inode->i_ino,
 372                            EXT4_I(inode)->i_file_acl);
 373                 error = -EIO;
 374                 goto cleanup;
 375         }
 376         ext4_xattr_cache_insert(bh);
 377         error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
 378
 379 cleanup:
 380         brelse(bh);
 381
 382         return error;
 383 }
 384
 385 static int
 386 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
 387 {
 388         struct ext4_xattr_ibody_header *header;
 389         struct ext4_inode *raw_inode;
 390         struct ext4_iloc iloc;
 391         void *end;
 392         int error;
 393
 394         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
 395                 return 0;
 396         error = ext4_get_inode_loc(inode, &iloc);
 397         if (error)
 398                 return error;
 399         raw_inode = ext4_raw_inode(&iloc);
 400         header = IHDR(inode, raw_inode);
 401         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 402         error = ext4_xattr_check_names(IFIRST(header), end);
 403         if (error)
 404                 goto cleanup;
 405         error = ext4_xattr_list_entries(inode, IFIRST(header),
 406                                         buffer, buffer_size);
 407
 408 cleanup:
 409         brelse(iloc.bh);
 410         return error;
 411 }
 412
 413 /*
 414  * ext4_xattr_list()
 415  *
 416  * Copy a list of attribute names into the buffer
 417  * provided, or compute the buffer size required.
 418  * Buffer is NULL to compute the size of the buffer required.
 419  *
 420  * Returns a negative error number on failure, or the number of bytes
 421  * used / required on success.
 422  */
 423 int
 424 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
 425 {
 426         int i_error, b_error;
 427
 428         down_read(&EXT4_I(inode)->xattr_sem);
 429         i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
 430         if (i_error < 0) {
 431                 b_error = 0;
 432         } else {
 433                 if (buffer) {
 434                         buffer += i_error;
 435                         buffer_size -= i_error;
 436                 }
 437                 b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
 438                 if (b_error < 0)
 439                         i_error = 0;
 440         }
 441         up_read(&EXT4_I(inode)->xattr_sem);
 442         return i_error + b_error;
 443 }
 444
 445 /*
 446  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 447  * not set, set it.
 448  */
 449 static void ext4_xattr_update_super_block(handle_t *handle,
 450                                           struct super_block *sb)
 451 {
 452         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 453                 return;
 454
 455         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 456                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 457                 sb->s_dirt = 1;
 458                 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
 459         }
 460 }
 461
 462 /*
 463  * Release the xattr block BH: If the reference count is > 1, decrement
 464  * it; otherwise free the block.
 465  */
 466 static void
 467 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 468                          struct buffer_head *bh)
 469 {
 470         struct mb_cache_entry *ce = NULL;
 471         int error = 0;
 472
 473         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 474         error = ext4_journal_get_write_access(handle, bh);
 475         if (error)
 476                 goto out;
 477
 478         lock_buffer(bh);
 479         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 480                 ea_bdebug(bh, "refcount now=0; freeing");
 481                 if (ce)
 482                         mb_cache_entry_free(ce);
 483                 ext4_free_blocks(handle, inode, bh->b_blocknr, 1);
 484                 get_bh(bh);
 485                 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
 486         } else {
 487                 BHDR(bh)->h_refcount = cpu_to_le32(
 488                                 le32_to_cpu(BHDR(bh)->h_refcount) - 1);
 489                 error = ext4_journal_dirty_metadata(handle, bh);
 490                 if (IS_SYNC(inode))
 491                         handle->h_sync = 1;
 492                 DQUOT_FREE_BLOCK(inode, 1);
 493                 ea_bdebug(bh, "refcount now=%d; releasing",
 494                           le32_to_cpu(BHDR(bh)->h_refcount));
 495                 if (ce)
 496                         mb_cache_entry_release(ce);
 497         }
 498         unlock_buffer(bh);
 499 out:
 500         ext4_std_error(inode->i_sb, error);
 501         return;
 502 }
 503
 504 /*
 505  * Find the available free space for EAs. This also returns the total number of
 506  * bytes used by EA entries.
 507  */
 508 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 509                                     size_t *min_offs, void *base, int *total)
 510 {
 511         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 512                 *total += EXT4_XATTR_LEN(last->e_name_len);
 513                 if (!last->e_value_block && last->e_value_size) {
 514                         size_t offs = le16_to_cpu(last->e_value_offs);
 515                         if (offs < *min_offs)
 516                                 *min_offs = offs;
 517                 }
 518         }
 519         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 520 }
 521
 522 struct ext4_xattr_info {
 523         int name_index;
 524         const char *name;
 525         const void *value;
 526         size_t value_len;
 527 };
 528
 529 struct ext4_xattr_search {
 530         struct ext4_xattr_entry *first;
 531         void *base;
 532         void *end;
 533         struct ext4_xattr_entry *here;
 534         int not_found;
 535 };
 536
 537 static int
 538 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 539 {
 540         struct ext4_xattr_entry *last;
 541         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 542
 543         /* Compute min_offs and last. */
 544         last = s->first;
 545         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 546                 if (!last->e_value_block && last->e_value_size) {
 547                         size_t offs = le16_to_cpu(last->e_value_offs);
 548                         if (offs < min_offs)
 549                                 min_offs = offs;
 550                 }
 551         }
 552         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 553         if (!s->not_found) {
 554                 if (!s->here->e_value_block && s->here->e_value_size) {
 555                         size_t size = le32_to_cpu(s->here->e_value_size);
 556                         free += EXT4_XATTR_SIZE(size);
 557                 }
 558                 free += EXT4_XATTR_LEN(name_len);
 559         }
 560         if (i->value) {
 561                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 562                     free < EXT4_XATTR_LEN(name_len) +
 563                            EXT4_XATTR_SIZE(i->value_len))
 564                         return -ENOSPC;
 565         }
 566
 567         if (i->value && s->not_found) {
 568                 /* Insert the new name. */
 569                 size_t size = EXT4_XATTR_LEN(name_len);
 570                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 571                 memmove((void *)s->here + size, s->here, rest);
 572                 memset(s->here, 0, size);
 573                 s->here->e_name_index = i->name_index;
 574                 s->here->e_name_len = name_len;
 575                 memcpy(s->here->e_name, i->name, name_len);
 576         } else {
 577                 if (!s->here->e_value_block && s->here->e_value_size) {
 578                         void *first_val = s->base + min_offs;
 579                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 580                         void *val = s->base + offs;
 581                         size_t size = EXT4_XATTR_SIZE(
 582                                 le32_to_cpu(s->here->e_value_size));
 583
 584                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 585                                 /* The old and the new value have the same
 586                                    size. Just replace. */
 587                                 s->here->e_value_size =
 588                                         cpu_to_le32(i->value_len);
 589                                 memset(val + size - EXT4_XATTR_PAD, 0,
 590                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
 591                                 memcpy(val, i->value, i->value_len);
 592                                 return 0;
 593                         }
 594
 595                         /* Remove the old value. */
 596                         memmove(first_val + size, first_val, val - first_val);
 597                         memset(first_val, 0, size);
 598                         s->here->e_value_size = 0;
 599                         s->here->e_value_offs = 0;
 600                         min_offs += size;
 601
 602                         /* Adjust all value offsets. */
 603                         last = s->first;
 604                         while (!IS_LAST_ENTRY(last)) {
 605                                 size_t o = le16_to_cpu(last->e_value_offs);
 606                                 if (!last->e_value_block &&
 607                                     last->e_value_size && o < offs)
 608                                         last->e_value_offs =
 609                                                 cpu_to_le16(o + size);
 610                                 last = EXT4_XATTR_NEXT(last);
 611                         }
 612                 }
 613                 if (!i->value) {
 614                         /* Remove the old name. */
 615                         size_t size = EXT4_XATTR_LEN(name_len);
 616                         last = ENTRY((void *)last - size);
 617                         memmove(s->here, (void *)s->here + size,
 618                                 (void *)last - (void *)s->here + sizeof(__u32));
 619                         memset(last, 0, size);
 620                 }
 621         }
 622
 623         if (i->value) {
 624                 /* Insert the new value. */
 625                 s->here->e_value_size = cpu_to_le32(i->value_len);
 626                 if (i->value_len) {
 627                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 628                         void *val = s->base + min_offs - size;
 629                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 630                         memset(val + size - EXT4_XATTR_PAD, 0,
 631                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
 632                         memcpy(val, i->value, i->value_len);
 633                 }
 634         }
 635         return 0;
 636 }
 637
 638 struct ext4_xattr_block_find {
 639         struct ext4_xattr_search s;
 640         struct buffer_head *bh;
 641 };
 642
 643 static int
 644 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 645                       struct ext4_xattr_block_find *bs)
 646 {
 647         struct super_block *sb = inode->i_sb;
 648         int error;
 649
 650         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 651                   i->name_index, i->name, i->value, (long)i->value_len);
 652
 653         if (EXT4_I(inode)->i_file_acl) {
 654                 /* The inode already has an extended attribute block. */
 655                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 656                 error = -EIO;
 657                 if (!bs->bh)
 658                         goto cleanup;
 659                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 660                         atomic_read(&(bs->bh->b_count)),
 661                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 662                 if (ext4_xattr_check_block(bs->bh)) {
 663                         ext4_error(sb, __FUNCTION__,
 664                                 "inode %lu: bad block %llu", inode->i_ino,
 665                                 EXT4_I(inode)->i_file_acl);
 666                         error = -EIO;
 667                         goto cleanup;
 668                 }
 669                 /* Find the named attribute. */
 670                 bs->s.base = BHDR(bs->bh);
 671                 bs->s.first = BFIRST(bs->bh);
 672                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 673                 bs->s.here = bs->s.first;
 674                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 675                                               i->name, bs->bh->b_size, 1);
 676                 if (error && error != -ENODATA)
 677                         goto cleanup;
 678                 bs->s.not_found = error;
 679         }
 680         error = 0;
 681
 682 cleanup:
 683         return error;
 684 }
 685
 686 static int
 687 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 688                      struct ext4_xattr_info *i,
 689                      struct ext4_xattr_block_find *bs)
 690 {
 691         struct super_block *sb = inode->i_sb;
 692         struct buffer_head *new_bh = NULL;
 693         struct ext4_xattr_search *s = &bs->s;
 694         struct mb_cache_entry *ce = NULL;
 695         int error = 0;
 696
 697 #define header(x) ((struct ext4_xattr_header *)(x))
 698
 699         if (i->value && i->value_len > sb->s_blocksize)
 700                 return -ENOSPC;
 701         if (s->base) {
 702                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 703                                         bs->bh->b_blocknr);
 704                 error = ext4_journal_get_write_access(handle, bs->bh);
 705                 if (error)
 706                         goto cleanup;
 707                 lock_buffer(bs->bh);
 708
 709                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 710                         if (ce) {
 711                                 mb_cache_entry_free(ce);
 712                                 ce = NULL;
 713                         }
 714                         ea_bdebug(bs->bh, "modifying in-place");
 715                         error = ext4_xattr_set_entry(i, s);
 716                         if (!error) {
 717                                 if (!IS_LAST_ENTRY(s->first))
 718                                         ext4_xattr_rehash(header(s->base),
 719                                                           s->here);
 720                                 ext4_xattr_cache_insert(bs->bh);
 721                         }
 722                         unlock_buffer(bs->bh);
 723                         if (error == -EIO)
 724                                 goto bad_block;
 725                         if (!error)
 726                                 error = ext4_journal_dirty_metadata(handle,
 727                                                                     bs->bh);
 728                         if (error)
 729                                 goto cleanup;
 730                         goto inserted;
 731                 } else {
 732                         int offset = (char *)s->here - bs->bh->b_data;
 733
 734                         unlock_buffer(bs->bh);
 735                         jbd2_journal_release_buffer(handle, bs->bh);
 736                         if (ce) {
 737                                 mb_cache_entry_release(ce);
 738                                 ce = NULL;
 739                         }
 740                         ea_bdebug(bs->bh, "cloning");
 741                         s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
 742                         error = -ENOMEM;
 743                         if (s->base == NULL)
 744                                 goto cleanup;
 745                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 746                         s->first = ENTRY(header(s->base)+1);
 747                         header(s->base)->h_refcount = cpu_to_le32(1);
 748                         s->here = ENTRY(s->base + offset);
 749                         s->end = s->base + bs->bh->b_size;
 750                 }
 751         } else {
 752                 /* Allocate a buffer where we construct the new block. */
 753                 s->base = kmalloc(sb->s_blocksize, GFP_KERNEL);
 754                 /* assert(header == s->base) */
 755                 error = -ENOMEM;
 756                 if (s->base == NULL)
 757                         goto cleanup;
 758                 memset(s->base, 0, sb->s_blocksize);
 759                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 760                 header(s->base)->h_blocks = cpu_to_le32(1);
 761                 header(s->base)->h_refcount = cpu_to_le32(1);
 762                 s->first = ENTRY(header(s->base)+1);
 763                 s->here = ENTRY(header(s->base)+1);
 764                 s->end = s->base + sb->s_blocksize;
 765         }
 766
 767         error = ext4_xattr_set_entry(i, s);
 768         if (error == -EIO)
 769                 goto bad_block;
 770         if (error)
 771                 goto cleanup;
 772         if (!IS_LAST_ENTRY(s->first))
 773                 ext4_xattr_rehash(header(s->base), s->here);
 774
 775 inserted:
 776         if (!IS_LAST_ENTRY(s->first)) {
 777                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 778                 if (new_bh) {
 779                         /* We found an identical block in the cache. */
 780                         if (new_bh == bs->bh)
 781                                 ea_bdebug(new_bh, "keeping");
 782                         else {
 783                                 /* The old block is released after updating
 784                                    the inode. */
 785                                 error = -EDQUOT;
 786                                 if (DQUOT_ALLOC_BLOCK(inode, 1))
 787                                         goto cleanup;
 788                                 error = ext4_journal_get_write_access(handle,
 789                                                                       new_bh);
 790                                 if (error)
 791                                         goto cleanup_dquot;
 792                                 lock_buffer(new_bh);
 793                                 BHDR(new_bh)->h_refcount = cpu_to_le32(1 +
 794                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 795                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 796                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 797                                 unlock_buffer(new_bh);
 798                                 error = ext4_journal_dirty_metadata(handle,
 799                                                                     new_bh);
 800                                 if (error)
 801                                         goto cleanup_dquot;
 802                         }
 803                         mb_cache_entry_release(ce);
 804                         ce = NULL;
 805                 } else if (bs->bh && s->base == bs->bh->b_data) {
 806                         /* We were modifying this block in-place. */
 807                         ea_bdebug(bs->bh, "keeping this block");
 808                         new_bh = bs->bh;
 809                         get_bh(new_bh);
 810                 } else {
 811                         /* We need to allocate a new block */
 812                         ext4_fsblk_t goal = le32_to_cpu(
 813                                         EXT4_SB(sb)->s_es->s_first_data_block) +
 814                                 (ext4_fsblk_t)EXT4_I(inode)->i_block_group *
 815                                 EXT4_BLOCKS_PER_GROUP(sb);
 816                         ext4_fsblk_t block = ext4_new_block(handle, inode,
 817                                                         goal, &error);
 818                         if (error)
 819                                 goto cleanup;
 820                         ea_idebug(inode, "creating block %d", block);
 821
 822                         new_bh = sb_getblk(sb, block);
 823                         if (!new_bh) {
 824 getblk_failed:
 825                                 ext4_free_blocks(handle, inode, block, 1);
 826                                 error = -EIO;
 827                                 goto cleanup;
 828                         }
 829                         lock_buffer(new_bh);
 830                         error = ext4_journal_get_create_access(handle, new_bh);
 831                         if (error) {
 832                                 unlock_buffer(new_bh);
 833                                 goto getblk_failed;
 834                         }
 835                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 836                         set_buffer_uptodate(new_bh);
 837                         unlock_buffer(new_bh);
 838                         ext4_xattr_cache_insert(new_bh);
 839                         error = ext4_journal_dirty_metadata(handle, new_bh);
 840                         if (error)
 841                                 goto cleanup;
 842                 }
 843         }
 844
 845         /* Update the inode. */
 846         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 847
 848         /* Drop the previous xattr block. */
 849         if (bs->bh && bs->bh != new_bh)
 850                 ext4_xattr_release_block(handle, inode, bs->bh);
 851         error = 0;
 852
 853 cleanup:
 854         if (ce)
 855                 mb_cache_entry_release(ce);
 856         brelse(new_bh);
 857         if (!(bs->bh && s->base == bs->bh->b_data))
 858                 kfree(s->base);
 859
 860         return error;
 861
 862 cleanup_dquot:
 863         DQUOT_FREE_BLOCK(inode, 1);
 864         goto cleanup;
 865
 866 bad_block:
 867         ext4_error(inode->i_sb, __FUNCTION__,
 868                    "inode %lu: bad block %llu", inode->i_ino,
 869                    EXT4_I(inode)->i_file_acl);
 870         goto cleanup;
 871
 872 #undef header
 873 }
 874
 875 struct ext4_xattr_ibody_find {
 876         struct ext4_xattr_search s;
 877         struct ext4_iloc iloc;
 878 };
 879
 880 static int
 881 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 882                       struct ext4_xattr_ibody_find *is)
 883 {
 884         struct ext4_xattr_ibody_header *header;
 885         struct ext4_inode *raw_inode;
 886         int error;
 887
 888         if (EXT4_I(inode)->i_extra_isize == 0)
 889                 return 0;
 890         raw_inode = ext4_raw_inode(&is->iloc);
 891         header = IHDR(inode, raw_inode);
 892         is->s.base = is->s.first = IFIRST(header);
 893         is->s.here = is->s.first;
 894         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 895         if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
 896                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 897                 if (error)
 898                         return error;
 899                 /* Find the named attribute. */
 900                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 901                                               i->name, is->s.end -
 902                                               (void *)is->s.base, 0);
 903                 if (error && error != -ENODATA)
 904                         return error;
 905                 is->s.not_found = error;
 906         }
 907         return 0;
 908 }
 909
 910 static int
 911 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 912                      struct ext4_xattr_info *i,
 913                      struct ext4_xattr_ibody_find *is)
 914 {
 915         struct ext4_xattr_ibody_header *header;
 916         struct ext4_xattr_search *s = &is->s;
 917         int error;
 918
 919         if (EXT4_I(inode)->i_extra_isize == 0)
 920                 return -ENOSPC;
 921         error = ext4_xattr_set_entry(i, s);
 922         if (error)
 923                 return error;
 924         header = IHDR(inode, ext4_raw_inode(&is->iloc));
 925         if (!IS_LAST_ENTRY(s->first)) {
 926                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 927                 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
 928         } else {
 929                 header->h_magic = cpu_to_le32(0);
 930                 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
 931         }
 932         return 0;
 933 }
 934
 935 /*
 936  * ext4_xattr_set_handle()
 937  *
 938  * Create, replace or remove an extended attribute for this inode. Buffer
 939  * is NULL to remove an existing extended attribute, and non-NULL to
 940  * either replace an existing extended attribute, or create a new extended
 941  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
 942  * specify that an extended attribute must exist and must not exist
 943  * previous to the call, respectively.
 944  *
 945  * Returns 0, or a negative error number on failure.
 946  */
 947 int
 948 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 949                       const char *name, const void *value, size_t value_len,
 950                       int flags)
 951 {
 952         struct ext4_xattr_info i = {
 953                 .name_index = name_index,
 954                 .name = name,
 955                 .value = value,
 956                 .value_len = value_len,
 957
 958         };
 959         struct ext4_xattr_ibody_find is = {
 960                 .s = { .not_found = -ENODATA, },
 961         };
 962         struct ext4_xattr_block_find bs = {
 963                 .s = { .not_found = -ENODATA, },
 964         };
 965         int error;
 966
 967         if (!name)
 968                 return -EINVAL;
 969         if (strlen(name) > 255)
 970                 return -ERANGE;
 971         down_write(&EXT4_I(inode)->xattr_sem);
 972         error = ext4_get_inode_loc(inode, &is.iloc);
 973         if (error)
 974                 goto cleanup;
 975
 976         if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
 977                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
 978                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
 979                 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
 980         }
 981
 982         error = ext4_xattr_ibody_find(inode, &i, &is);
 983         if (error)
 984                 goto cleanup;
 985         if (is.s.not_found)
 986                 error = ext4_xattr_block_find(inode, &i, &bs);
 987         if (error)
 988                 goto cleanup;
 989         if (is.s.not_found && bs.s.not_found) {
 990                 error = -ENODATA;
 991                 if (flags & XATTR_REPLACE)
 992                         goto cleanup;
 993                 error = 0;
 994                 if (!value)
 995                         goto cleanup;
 996         } else {
 997                 error = -EEXIST;
 998                 if (flags & XATTR_CREATE)
 999                         goto cleanup;
1000         }
1001         error = ext4_journal_get_write_access(handle, is.iloc.bh);
1002         if (error)
1003                 goto cleanup;
1004         if (!value) {
1005                 if (!is.s.not_found)
1006                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1007                 else if (!bs.s.not_found)
1008                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1009         } else {
1010                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1011                 if (!error && !bs.s.not_found) {
1012                         i.value = NULL;
1013                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1014                 } else if (error == -ENOSPC) {
1015                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1016                         if (error)
1017                                 goto cleanup;
1018                         if (!is.s.not_found) {
1019                                 i.value = NULL;
1020                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1021                                                              &is);
1022                         }
1023                 }
1024         }
1025         if (!error) {
1026                 ext4_xattr_update_super_block(handle, inode->i_sb);
1027                 inode->i_ctime = ext4_current_time(inode);
1028                 if (!value)
1029                         EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1030                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1031                 /*
1032                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1033                  * error != 0.
1034                  */
1035                 is.iloc.bh = NULL;
1036                 if (IS_SYNC(inode))
1037                         handle->h_sync = 1;
1038         }
1039
1040 cleanup:
1041         brelse(is.iloc.bh);
1042         brelse(bs.bh);
1043         up_write(&EXT4_I(inode)->xattr_sem);
1044         return error;
1045 }
1046
1047 /*
1048  * ext4_xattr_set()
1049  *
1050  * Like ext4_xattr_set_handle, but start from an inode. This extended
1051  * attribute modification is a filesystem transaction by itself.
1052  *
1053  * Returns 0, or a negative error number on failure.
1054  */
1055 int
1056 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1057                const void *value, size_t value_len, int flags)
1058 {
1059         handle_t *handle;
1060         int error, retries = 0;
1061
1062 retry:
1063         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1064         if (IS_ERR(handle)) {
1065                 error = PTR_ERR(handle);
1066         } else {
1067                 int error2;
1068
1069                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1070                                               value, value_len, flags);
1071                 error2 = ext4_journal_stop(handle);
1072                 if (error == -ENOSPC &&
1073                     ext4_should_retry_alloc(inode->i_sb, &retries))
1074                         goto retry;
1075                 if (error == 0)
1076                         error = error2;
1077         }
1078
1079         return error;
1080 }
1081
1082 /*
1083  * Shift the EA entries in the inode to create space for the increased
1084  * i_extra_isize.
1085  */
1086 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1087                                      int value_offs_shift, void *to,
1088                                      void *from, size_t n, int blocksize)
1089 {
1090         struct ext4_xattr_entry *last = entry;
1091         int new_offs;
1092
1093         /* Adjust the value offsets of the entries */
1094         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1095                 if (!last->e_value_block && last->e_value_size) {
1096                         new_offs = le16_to_cpu(last->e_value_offs) +
1097                                                         value_offs_shift;
1098                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1099                                  > blocksize);
1100                         last->e_value_offs = cpu_to_le16(new_offs);
1101                 }
1102         }
1103         /* Shift the entries by n bytes */
1104         memmove(to, from, n);
1105 }
1106
1107 /*
1108  * Expand an inode by new_extra_isize bytes when EAs are present.
1109  * Returns 0 on success or negative error number on failure.
1110  */
1111 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1112                                struct ext4_inode *raw_inode, handle_t *handle)
1113 {
1114         struct ext4_xattr_ibody_header *header;
1115         struct ext4_xattr_entry *entry, *last, *first;
1116         struct buffer_head *bh = NULL;
1117         struct ext4_xattr_ibody_find *is = NULL;
1118         struct ext4_xattr_block_find *bs = NULL;
1119         char *buffer = NULL, *b_entry_name = NULL;
1120         size_t min_offs, free;
1121         int total_ino, total_blk;
1122         void *base, *start, *end;
1123         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1124         int s_min_extra_isize = EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize;
1125
1126         down_write(&EXT4_I(inode)->xattr_sem);
1127 retry:
1128         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1129                 up_write(&EXT4_I(inode)->xattr_sem);
1130                 return 0;
1131         }
1132
1133         header = IHDR(inode, raw_inode);
1134         entry = IFIRST(header);
1135
1136         /*
1137          * Check if enough free space is available in the inode to shift the
1138          * entries ahead by new_extra_isize.
1139          */
1140
1141         base = start = entry;
1142         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1143         min_offs = end - base;
1144         last = entry;
1145         total_ino = sizeof(struct ext4_xattr_ibody_header);
1146
1147         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1148         if (free >= new_extra_isize) {
1149                 entry = IFIRST(header);
1150                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1151                                 - new_extra_isize, (void *)raw_inode +
1152                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1153                                 (void *)header, total_ino,
1154                                 inode->i_sb->s_blocksize);
1155                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1156                 error = 0;
1157                 goto cleanup;
1158         }
1159
1160         /*
1161          * Enough free space isn't available in the inode, check if
1162          * EA block can hold new_extra_isize bytes.
1163          */
1164         if (EXT4_I(inode)->i_file_acl) {
1165                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1166                 error = -EIO;
1167                 if (!bh)
1168                         goto cleanup;
1169                 if (ext4_xattr_check_block(bh)) {
1170                         ext4_error(inode->i_sb, __FUNCTION__,
1171                                 "inode %lu: bad block %llu", inode->i_ino,
1172                                 EXT4_I(inode)->i_file_acl);
1173                         error = -EIO;
1174                         goto cleanup;
1175                 }
1176                 base = BHDR(bh);
1177                 first = BFIRST(bh);
1178                 end = bh->b_data + bh->b_size;
1179                 min_offs = end - base;
1180                 free = ext4_xattr_free_space(first, &min_offs, base,
1181                                              &total_blk);
1182                 if (free < new_extra_isize) {
1183                         if (!tried_min_extra_isize && s_min_extra_isize) {
1184                                 tried_min_extra_isize++;
1185                                 new_extra_isize = s_min_extra_isize;
1186                                 brelse(bh);
1187                                 goto retry;
1188                         }
1189                         error = -1;
1190                         goto cleanup;
1191                 }
1192         } else {
1193                 free = inode->i_sb->s_blocksize;
1194         }
1195
1196         while (new_extra_isize > 0) {
1197                 size_t offs, size, entry_size;
1198                 struct ext4_xattr_entry *small_entry = NULL;
1199                 struct ext4_xattr_info i = {
1200                         .value = NULL,
1201                         .value_len = 0,
1202                 };
1203                 unsigned int total_size;  /* EA entry size + value size */
1204                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1205                 unsigned int min_total_size = ~0U;
1206
1207                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1208                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1209                 if (!is || !bs) {
1210                         error = -ENOMEM;
1211                         goto cleanup;
1212                 }
1213
1214                 is->s.not_found = -ENODATA;
1215                 bs->s.not_found = -ENODATA;
1216                 is->iloc.bh = NULL;
1217                 bs->bh = NULL;
1218
1219                 last = IFIRST(header);
1220                 /* Find the entry best suited to be pushed into EA block */
1221                 entry = NULL;
1222                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1223                         total_size =
1224                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1225                                         EXT4_XATTR_LEN(last->e_name_len);
1226                         if (total_size <= free && total_size < min_total_size) {
1227                                 if (total_size < new_extra_isize) {
1228                                         small_entry = last;
1229                                 } else {
1230                                         entry = last;
1231                                         min_total_size = total_size;
1232                                 }
1233                         }
1234                 }
1235
1236                 if (entry == NULL) {
1237                         if (small_entry) {
1238                                 entry = small_entry;
1239                         } else {
1240                                 if (!tried_min_extra_isize &&
1241                                     s_min_extra_isize) {
1242                                         tried_min_extra_isize++;
1243                                         new_extra_isize = s_min_extra_isize;
1244                                         goto retry;
1245                                 }
1246                                 error = -1;
1247                                 goto cleanup;
1248                         }
1249                 }
1250                 offs = le16_to_cpu(entry->e_value_offs);
1251                 size = le32_to_cpu(entry->e_value_size);
1252                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1253                 i.name_index = entry->e_name_index,
1254                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1255                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1256                 if (!buffer || !b_entry_name) {
1257                         error = -ENOMEM;
1258                         goto cleanup;
1259                 }
1260                 /* Save the entry name and the entry value */
1261                 memcpy(buffer, (void *)IFIRST(header) + offs,
1262                        EXT4_XATTR_SIZE(size));
1263                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1264                 b_entry_name[entry->e_name_len] = '\0';
1265                 i.name = b_entry_name;
1266
1267                 error = ext4_get_inode_loc(inode, &is->iloc);
1268                 if (error)
1269                         goto cleanup;
1270
1271                 error = ext4_xattr_ibody_find(inode, &i, is);
1272                 if (error)
1273                         goto cleanup;
1274
1275                 /* Remove the chosen entry from the inode */
1276                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1277
1278                 entry = IFIRST(header);
1279                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1280                         shift_bytes = new_extra_isize;
1281                 else
1282                         shift_bytes = entry_size + size;
1283                 /* Adjust the offsets and shift the remaining entries ahead */
1284                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1285                         shift_bytes, (void *)raw_inode +
1286                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1287                         (void *)header, total_ino - entry_size,
1288                         inode->i_sb->s_blocksize);
1289
1290                 extra_isize += shift_bytes;
1291                 new_extra_isize -= shift_bytes;
1292                 EXT4_I(inode)->i_extra_isize = extra_isize;
1293
1294                 i.name = b_entry_name;
1295                 i.value = buffer;
1296                 i.value_len = cpu_to_le32(size);
1297                 error = ext4_xattr_block_find(inode, &i, bs);
1298                 if (error)
1299                         goto cleanup;
1300
1301                 /* Add entry which was removed from the inode into the block */
1302                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1303                 if (error)
1304                         goto cleanup;
1305                 kfree(b_entry_name);
1306                 kfree(buffer);
1307                 brelse(is->iloc.bh);
1308                 kfree(is);
1309                 kfree(bs);
1310         }
1311         brelse(bh);
1312         up_write(&EXT4_I(inode)->xattr_sem);
1313         return 0;
1314
1315 cleanup:
1316         kfree(b_entry_name);
1317         kfree(buffer);
1318         if (is)
1319                 brelse(is->iloc.bh);
1320         kfree(is);
1321         kfree(bs);
1322         brelse(bh);
1323         up_write(&EXT4_I(inode)->xattr_sem);
1324         return error;
1325 }
1326
1327
1328
1329 /*
1330  * ext4_xattr_delete_inode()
1331  *
1332  * Free extended attribute resources associated with this inode. This
1333  * is called immediately before an inode is freed. We have exclusive
1334  * access to the inode.
1335  */
1336 void
1337 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1338 {
1339         struct buffer_head *bh = NULL;
1340
1341         if (!EXT4_I(inode)->i_file_acl)
1342                 goto cleanup;
1343         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1344         if (!bh) {
1345                 ext4_error(inode->i_sb, __FUNCTION__,
1346                         "inode %lu: block %llu read error", inode->i_ino,
1347                         EXT4_I(inode)->i_file_acl);
1348                 goto cleanup;
1349         }
1350         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1351             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1352                 ext4_error(inode->i_sb, __FUNCTION__,
1353                         "inode %lu: bad block %llu", inode->i_ino,
1354                         EXT4_I(inode)->i_file_acl);
1355                 goto cleanup;
1356         }
1357         ext4_xattr_release_block(handle, inode, bh);
1358         EXT4_I(inode)->i_file_acl = 0;
1359
1360 cleanup:
1361         brelse(bh);
1362 }
1363
1364 /*
1365  * ext4_xattr_put_super()
1366  *
1367  * This is called when a file system is unmounted.
1368  */
1369 void
1370 ext4_xattr_put_super(struct super_block *sb)
1371 {
1372         mb_cache_shrink(sb->s_bdev);
1373 }
1374
1375 /*
1376  * ext4_xattr_cache_insert()
1377  *
1378  * Create a new entry in the extended attribute cache, and insert
1379  * it unless such an entry is already in the cache.
1380  *
1381  * Returns 0, or a negative error number on failure.
1382  */
1383 static void
1384 ext4_xattr_cache_insert(struct buffer_head *bh)
1385 {
1386         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1387         struct mb_cache_entry *ce;
1388         int error;
1389
1390         ce = mb_cache_entry_alloc(ext4_xattr_cache);
1391         if (!ce) {
1392                 ea_bdebug(bh, "out of memory");
1393                 return;
1394         }
1395         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1396         if (error) {
1397                 mb_cache_entry_free(ce);
1398                 if (error == -EBUSY) {
1399                         ea_bdebug(bh, "already in cache");
1400                         error = 0;
1401                 }
1402         } else {
1403                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1404                 mb_cache_entry_release(ce);
1405         }
1406 }
1407
1408 /*
1409  * ext4_xattr_cmp()
1410  *
1411  * Compare two extended attribute blocks for equality.
1412  *
1413  * Returns 0 if the blocks are equal, 1 if they differ, and
1414  * a negative error number on errors.
1415  */
1416 static int
1417 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1418                struct ext4_xattr_header *header2)
1419 {
1420         struct ext4_xattr_entry *entry1, *entry2;
1421
1422         entry1 = ENTRY(header1+1);
1423         entry2 = ENTRY(header2+1);
1424         while (!IS_LAST_ENTRY(entry1)) {
1425                 if (IS_LAST_ENTRY(entry2))
1426                         return 1;
1427                 if (entry1->e_hash != entry2->e_hash ||
1428                     entry1->e_name_index != entry2->e_name_index ||
1429                     entry1->e_name_len != entry2->e_name_len ||
1430                     entry1->e_value_size != entry2->e_value_size ||
1431                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1432                         return 1;
1433                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1434                         return -EIO;
1435                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1436                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1437                            le32_to_cpu(entry1->e_value_size)))
1438                         return 1;
1439
1440                 entry1 = EXT4_XATTR_NEXT(entry1);
1441                 entry2 = EXT4_XATTR_NEXT(entry2);
1442         }
1443         if (!IS_LAST_ENTRY(entry2))
1444                 return 1;
1445         return 0;
1446 }
1447
1448 /*
1449  * ext4_xattr_cache_find()
1450  *
1451  * Find an identical extended attribute block.
1452  *
1453  * Returns a pointer to the block found, or NULL if such a block was
1454  * not found or an error occurred.
1455  */
1456 static struct buffer_head *
1457 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1458                       struct mb_cache_entry **pce)
1459 {
1460         __u32 hash = le32_to_cpu(header->h_hash);
1461         struct mb_cache_entry *ce;
1462
1463         if (!header->h_hash)
1464                 return NULL;  /* never share */
1465         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1466 again:
1467         ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1468                                        inode->i_sb->s_bdev, hash);
1469         while (ce) {
1470                 struct buffer_head *bh;
1471
1472                 if (IS_ERR(ce)) {
1473                         if (PTR_ERR(ce) == -EAGAIN)
1474                                 goto again;
1475                         break;
1476                 }
1477                 bh = sb_bread(inode->i_sb, ce->e_block);
1478                 if (!bh) {
1479                         ext4_error(inode->i_sb, __FUNCTION__,
1480                                 "inode %lu: block %lu read error",
1481                                 inode->i_ino, (unsigned long) ce->e_block);
1482                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1483                                 EXT4_XATTR_REFCOUNT_MAX) {
1484                         ea_idebug(inode, "block %lu refcount %d>=%d",
1485                                   (unsigned long) ce->e_block,
1486                                   le32_to_cpu(BHDR(bh)->h_refcount),
1487                                           EXT4_XATTR_REFCOUNT_MAX);
1488                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1489                         *pce = ce;
1490                         return bh;
1491                 }
1492                 brelse(bh);
1493                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1494         }
1495         return NULL;
1496 }
1497
1498 #define NAME_HASH_SHIFT 5
1499 #define VALUE_HASH_SHIFT 16
1500
1501 /*
1502  * ext4_xattr_hash_entry()
1503  *
1504  * Compute the hash of an extended attribute.
1505  */
1506 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1507                                          struct ext4_xattr_entry *entry)
1508 {
1509         __u32 hash = 0;
1510         char *name = entry->e_name;
1511         int n;
1512
1513         for (n=0; n < entry->e_name_len; n++) {
1514                 hash = (hash << NAME_HASH_SHIFT) ^
1515                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1516                        *name++;
1517         }
1518
1519         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1520                 __le32 *value = (__le32 *)((char *)header +
1521                         le16_to_cpu(entry->e_value_offs));
1522                 for (n = (le32_to_cpu(entry->e_value_size) +
1523                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1524                         hash = (hash << VALUE_HASH_SHIFT) ^
1525                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1526                                le32_to_cpu(*value++);
1527                 }
1528         }
1529         entry->e_hash = cpu_to_le32(hash);
1530 }
1531
1532 #undef NAME_HASH_SHIFT
1533 #undef VALUE_HASH_SHIFT
1534
1535 #define BLOCK_HASH_SHIFT 16
1536
1537 /*
1538  * ext4_xattr_rehash()
1539  *
1540  * Re-compute the extended attribute hash value after an entry has changed.
1541  */
1542 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1543                               struct ext4_xattr_entry *entry)
1544 {
1545         struct ext4_xattr_entry *here;
1546         __u32 hash = 0;
1547
1548         ext4_xattr_hash_entry(header, entry);
1549         here = ENTRY(header+1);
1550         while (!IS_LAST_ENTRY(here)) {
1551                 if (!here->e_hash) {
1552                         /* Block is not shared if an entry's hash value == 0 */
1553                         hash = 0;
1554                         break;
1555                 }
1556                 hash = (hash << BLOCK_HASH_SHIFT) ^
1557                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1558                        le32_to_cpu(here->e_hash);
1559                 here = EXT4_XATTR_NEXT(here);
1560         }
1561         header->h_hash = cpu_to_le32(hash);
1562 }
1563
1564 #undef BLOCK_HASH_SHIFT
1565
1566 int __init
1567 init_ext4_xattr(void)
1568 {
1569         ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1570                 sizeof(struct mb_cache_entry) +
1571                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1572         if (!ext4_xattr_cache)
1573                 return -ENOMEM;
1574         return 0;
1575 }
1576
1577 void
1578 exit_ext4_xattr(void)
1579 {
1580         if (ext4_xattr_cache)
1581                 mb_cache_destroy(ext4_xattr_cache);
1582         ext4_xattr_cache = NULL;
1583 }