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(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 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 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 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 inline struct xattr_handler *
 126 ext4_xattr_handler(int name_index)
 127 {
 128         struct xattr_handler *handler = NULL;
 129
 130         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 131                 handler = ext4_xattr_handler_map[name_index];
 132         return handler;
 133 }
 134
 135 /*
 136  * Inode operation listxattr()
 137  *
 138  * dentry->d_inode->i_mutex: don't care
 139  */
 140 ssize_t
 141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
 142 {
 143         return ext4_xattr_list(dentry, buffer, size);
 144 }
 145
 146 static int
 147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 148 {
 149         while (!IS_LAST_ENTRY(entry)) {
 150                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
 151                 if ((void *)next >= end)
 152                         return -EIO;
 153                 entry = next;
 154         }
 155         return 0;
 156 }
 157
 158 static inline int
 159 ext4_xattr_check_block(struct buffer_head *bh)
 160 {
 161         int error;
 162
 163         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 164             BHDR(bh)->h_blocks != cpu_to_le32(1))
 165                 return -EIO;
 166         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 167         return error;
 168 }
 169
 170 static inline int
 171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 172 {
 173         size_t value_size = le32_to_cpu(entry->e_value_size);
 174
 175         if (entry->e_value_block != 0 || value_size > size ||
 176             le16_to_cpu(entry->e_value_offs) + value_size > size)
 177                 return -EIO;
 178         return 0;
 179 }
 180
 181 static int
 182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 183                       const char *name, size_t size, int sorted)
 184 {
 185         struct ext4_xattr_entry *entry;
 186         size_t name_len;
 187         int cmp = 1;
 188
 189         if (name == NULL)
 190                 return -EINVAL;
 191         name_len = strlen(name);
 192         entry = *pentry;
 193         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 194                 cmp = name_index - entry->e_name_index;
 195                 if (!cmp)
 196                         cmp = name_len - entry->e_name_len;
 197                 if (!cmp)
 198                         cmp = memcmp(name, entry->e_name, name_len);
 199                 if (cmp <= 0 && (sorted || cmp == 0))
 200                         break;
 201         }
 202         *pentry = entry;
 203         if (!cmp && ext4_xattr_check_entry(entry, size))
 204                         return -EIO;
 205         return cmp ? -ENODATA : 0;
 206 }
 207
 208 static int
 209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 210                      void *buffer, size_t buffer_size)
 211 {
 212         struct buffer_head *bh = NULL;
 213         struct ext4_xattr_entry *entry;
 214         size_t size;
 215         int error;
 216
 217         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 218                   name_index, name, buffer, (long)buffer_size);
 219
 220         error = -ENODATA;
 221         if (!EXT4_I(inode)->i_file_acl)
 222                 goto cleanup;
 223         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
 224         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 225         if (!bh)
 226                 goto cleanup;
 227         ea_bdebug(bh, "b_count=%d, refcount=%d",
 228                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 229         if (ext4_xattr_check_block(bh)) {
 230 bad_block:      ext4_error(inode->i_sb, __func__,
 231                            "inode %lu: bad block %llu", inode->i_ino,
 232                            EXT4_I(inode)->i_file_acl);
 233                 error = -EIO;
 234                 goto cleanup;
 235         }
 236         ext4_xattr_cache_insert(bh);
 237         entry = BFIRST(bh);
 238         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 239         if (error == -EIO)
 240                 goto bad_block;
 241         if (error)
 242                 goto cleanup;
 243         size = le32_to_cpu(entry->e_value_size);
 244         if (buffer) {
 245                 error = -ERANGE;
 246                 if (size > buffer_size)
 247                         goto cleanup;
 248                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 249                        size);
 250         }
 251         error = size;
 252
 253 cleanup:
 254         brelse(bh);
 255         return error;
 256 }
 257
 258 static int
 259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 260                      void *buffer, size_t buffer_size)
 261 {
 262         struct ext4_xattr_ibody_header *header;
 263         struct ext4_xattr_entry *entry;
 264         struct ext4_inode *raw_inode;
 265         struct ext4_iloc iloc;
 266         size_t size;
 267         void *end;
 268         int error;
 269
 270         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
 271                 return -ENODATA;
 272         error = ext4_get_inode_loc(inode, &iloc);
 273         if (error)
 274                 return error;
 275         raw_inode = ext4_raw_inode(&iloc);
 276         header = IHDR(inode, raw_inode);
 277         entry = IFIRST(header);
 278         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 279         error = ext4_xattr_check_names(entry, end);
 280         if (error)
 281                 goto cleanup;
 282         error = ext4_xattr_find_entry(&entry, name_index, name,
 283                                       end - (void *)entry, 0);
 284         if (error)
 285                 goto cleanup;
 286         size = le32_to_cpu(entry->e_value_size);
 287         if (buffer) {
 288                 error = -ERANGE;
 289                 if (size > buffer_size)
 290                         goto cleanup;
 291                 memcpy(buffer, (void *)IFIRST(header) +
 292                        le16_to_cpu(entry->e_value_offs), size);
 293         }
 294         error = size;
 295
 296 cleanup:
 297         brelse(iloc.bh);
 298         return error;
 299 }
 300
 301 /*
 302  * ext4_xattr_get()
 303  *
 304  * Copy an extended attribute into the buffer
 305  * provided, or compute the buffer size required.
 306  * Buffer is NULL to compute the size of the buffer required.
 307  *
 308  * Returns a negative error number on failure, or the number of bytes
 309  * used / required on success.
 310  */
 311 int
 312 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 313                void *buffer, size_t buffer_size)
 314 {
 315         int error;
 316
 317         down_read(&EXT4_I(inode)->xattr_sem);
 318         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 319                                      buffer_size);
 320         if (error == -ENODATA)
 321                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 322                                              buffer_size);
 323         up_read(&EXT4_I(inode)->xattr_sem);
 324         return error;
 325 }
 326
 327 static int
 328 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 329                         char *buffer, size_t buffer_size)
 330 {
 331         size_t rest = buffer_size;
 332
 333         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 334                 struct xattr_handler *handler =
 335                         ext4_xattr_handler(entry->e_name_index);
 336
 337                 if (handler) {
 338                         size_t size = handler->list(dentry, buffer, rest,
 339                                                     entry->e_name,
 340                                                     entry->e_name_len,
 341                                                     handler->flags);
 342                         if (buffer) {
 343                                 if (size > rest)
 344                                         return -ERANGE;
 345                                 buffer += size;
 346                         }
 347                         rest -= size;
 348                 }
 349         }
 350         return buffer_size - rest;
 351 }
 352
 353 static int
 354 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 355 {
 356         struct inode *inode = dentry->d_inode;
 357         struct buffer_head *bh = NULL;
 358         int error;
 359
 360         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 361                   buffer, (long)buffer_size);
 362
 363         error = 0;
 364         if (!EXT4_I(inode)->i_file_acl)
 365                 goto cleanup;
 366         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
 367         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 368         error = -EIO;
 369         if (!bh)
 370                 goto cleanup;
 371         ea_bdebug(bh, "b_count=%d, refcount=%d",
 372                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 373         if (ext4_xattr_check_block(bh)) {
 374                 ext4_error(inode->i_sb, __func__,
 375                            "inode %lu: bad block %llu", inode->i_ino,
 376                            EXT4_I(inode)->i_file_acl);
 377                 error = -EIO;
 378                 goto cleanup;
 379         }
 380         ext4_xattr_cache_insert(bh);
 381         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 382
 383 cleanup:
 384         brelse(bh);
 385
 386         return error;
 387 }
 388
 389 static int
 390 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 391 {
 392         struct inode *inode = dentry->d_inode;
 393         struct ext4_xattr_ibody_header *header;
 394         struct ext4_inode *raw_inode;
 395         struct ext4_iloc iloc;
 396         void *end;
 397         int error;
 398
 399         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
 400                 return 0;
 401         error = ext4_get_inode_loc(inode, &iloc);
 402         if (error)
 403                 return error;
 404         raw_inode = ext4_raw_inode(&iloc);
 405         header = IHDR(inode, raw_inode);
 406         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 407         error = ext4_xattr_check_names(IFIRST(header), end);
 408         if (error)
 409                 goto cleanup;
 410         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 411                                         buffer, buffer_size);
 412
 413 cleanup:
 414         brelse(iloc.bh);
 415         return error;
 416 }
 417
 418 /*
 419  * ext4_xattr_list()
 420  *
 421  * Copy a list of attribute names into the buffer
 422  * provided, or compute the buffer size required.
 423  * Buffer is NULL to compute the size of the buffer required.
 424  *
 425  * Returns a negative error number on failure, or the number of bytes
 426  * used / required on success.
 427  */
 428 static int
 429 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 430 {
 431         int i_error, b_error;
 432
 433         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 434         i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 435         if (i_error < 0) {
 436                 b_error = 0;
 437         } else {
 438                 if (buffer) {
 439                         buffer += i_error;
 440                         buffer_size -= i_error;
 441                 }
 442                 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
 443                 if (b_error < 0)
 444                         i_error = 0;
 445         }
 446         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 447         return i_error + b_error;
 448 }
 449
 450 /*
 451  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 452  * not set, set it.
 453  */
 454 static void ext4_xattr_update_super_block(handle_t *handle,
 455                                           struct super_block *sb)
 456 {
 457         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 458                 return;
 459
 460         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 461                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 462                 sb->s_dirt = 1;
 463                 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
 464         }
 465 }
 466
 467 /*
 468  * Release the xattr block BH: If the reference count is > 1, decrement
 469  * it; otherwise free the block.
 470  */
 471 static void
 472 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 473                          struct buffer_head *bh)
 474 {
 475         struct mb_cache_entry *ce = NULL;
 476         int error = 0;
 477
 478         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 479         error = ext4_journal_get_write_access(handle, bh);
 480         if (error)
 481                 goto out;
 482
 483         lock_buffer(bh);
 484         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 485                 ea_bdebug(bh, "refcount now=0; freeing");
 486                 if (ce)
 487                         mb_cache_entry_free(ce);
 488                 get_bh(bh);
 489                 ext4_free_blocks(handle, inode, bh, 0, 1,
 490                                  EXT4_FREE_BLOCKS_METADATA |
 491                                  EXT4_FREE_BLOCKS_FORGET);
 492         } else {
 493                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 494                 error = ext4_handle_dirty_metadata(handle, inode, bh);
 495                 if (IS_SYNC(inode))
 496                         ext4_handle_sync(handle);
 497                 vfs_dq_free_block(inode, 1);
 498                 ea_bdebug(bh, "refcount now=%d; releasing",
 499                           le32_to_cpu(BHDR(bh)->h_refcount));
 500                 if (ce)
 501                         mb_cache_entry_release(ce);
 502         }
 503         unlock_buffer(bh);
 504 out:
 505         ext4_std_error(inode->i_sb, error);
 506         return;
 507 }
 508
 509 /*
 510  * Find the available free space for EAs. This also returns the total number of
 511  * bytes used by EA entries.
 512  */
 513 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 514                                     size_t *min_offs, void *base, int *total)
 515 {
 516         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 517                 *total += EXT4_XATTR_LEN(last->e_name_len);
 518                 if (!last->e_value_block && last->e_value_size) {
 519                         size_t offs = le16_to_cpu(last->e_value_offs);
 520                         if (offs < *min_offs)
 521                                 *min_offs = offs;
 522                 }
 523         }
 524         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 525 }
 526
 527 struct ext4_xattr_info {
 528         int name_index;
 529         const char *name;
 530         const void *value;
 531         size_t value_len;
 532 };
 533
 534 struct ext4_xattr_search {
 535         struct ext4_xattr_entry *first;
 536         void *base;
 537         void *end;
 538         struct ext4_xattr_entry *here;
 539         int not_found;
 540 };
 541
 542 static int
 543 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 544 {
 545         struct ext4_xattr_entry *last;
 546         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 547
 548         /* Compute min_offs and last. */
 549         last = s->first;
 550         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 551                 if (!last->e_value_block && last->e_value_size) {
 552                         size_t offs = le16_to_cpu(last->e_value_offs);
 553                         if (offs < min_offs)
 554                                 min_offs = offs;
 555                 }
 556         }
 557         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 558         if (!s->not_found) {
 559                 if (!s->here->e_value_block && s->here->e_value_size) {
 560                         size_t size = le32_to_cpu(s->here->e_value_size);
 561                         free += EXT4_XATTR_SIZE(size);
 562                 }
 563                 free += EXT4_XATTR_LEN(name_len);
 564         }
 565         if (i->value) {
 566                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 567                     free < EXT4_XATTR_LEN(name_len) +
 568                            EXT4_XATTR_SIZE(i->value_len))
 569                         return -ENOSPC;
 570         }
 571
 572         if (i->value && s->not_found) {
 573                 /* Insert the new name. */
 574                 size_t size = EXT4_XATTR_LEN(name_len);
 575                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 576                 memmove((void *)s->here + size, s->here, rest);
 577                 memset(s->here, 0, size);
 578                 s->here->e_name_index = i->name_index;
 579                 s->here->e_name_len = name_len;
 580                 memcpy(s->here->e_name, i->name, name_len);
 581         } else {
 582                 if (!s->here->e_value_block && s->here->e_value_size) {
 583                         void *first_val = s->base + min_offs;
 584                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 585                         void *val = s->base + offs;
 586                         size_t size = EXT4_XATTR_SIZE(
 587                                 le32_to_cpu(s->here->e_value_size));
 588
 589                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 590                                 /* The old and the new value have the same
 591                                    size. Just replace. */
 592                                 s->here->e_value_size =
 593                                         cpu_to_le32(i->value_len);
 594                                 memset(val + size - EXT4_XATTR_PAD, 0,
 595                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
 596                                 memcpy(val, i->value, i->value_len);
 597                                 return 0;
 598                         }
 599
 600                         /* Remove the old value. */
 601                         memmove(first_val + size, first_val, val - first_val);
 602                         memset(first_val, 0, size);
 603                         s->here->e_value_size = 0;
 604                         s->here->e_value_offs = 0;
 605                         min_offs += size;
 606
 607                         /* Adjust all value offsets. */
 608                         last = s->first;
 609                         while (!IS_LAST_ENTRY(last)) {
 610                                 size_t o = le16_to_cpu(last->e_value_offs);
 611                                 if (!last->e_value_block &&
 612                                     last->e_value_size && o < offs)
 613                                         last->e_value_offs =
 614                                                 cpu_to_le16(o + size);
 615                                 last = EXT4_XATTR_NEXT(last);
 616                         }
 617                 }
 618                 if (!i->value) {
 619                         /* Remove the old name. */
 620                         size_t size = EXT4_XATTR_LEN(name_len);
 621                         last = ENTRY((void *)last - size);
 622                         memmove(s->here, (void *)s->here + size,
 623                                 (void *)last - (void *)s->here + sizeof(__u32));
 624                         memset(last, 0, size);
 625                 }
 626         }
 627
 628         if (i->value) {
 629                 /* Insert the new value. */
 630                 s->here->e_value_size = cpu_to_le32(i->value_len);
 631                 if (i->value_len) {
 632                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 633                         void *val = s->base + min_offs - size;
 634                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 635                         memset(val + size - EXT4_XATTR_PAD, 0,
 636                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
 637                         memcpy(val, i->value, i->value_len);
 638                 }
 639         }
 640         return 0;
 641 }
 642
 643 struct ext4_xattr_block_find {
 644         struct ext4_xattr_search s;
 645         struct buffer_head *bh;
 646 };
 647
 648 static int
 649 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 650                       struct ext4_xattr_block_find *bs)
 651 {
 652         struct super_block *sb = inode->i_sb;
 653         int error;
 654
 655         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 656                   i->name_index, i->name, i->value, (long)i->value_len);
 657
 658         if (EXT4_I(inode)->i_file_acl) {
 659                 /* The inode already has an extended attribute block. */
 660                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 661                 error = -EIO;
 662                 if (!bs->bh)
 663                         goto cleanup;
 664                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 665                         atomic_read(&(bs->bh->b_count)),
 666                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 667                 if (ext4_xattr_check_block(bs->bh)) {
 668                         ext4_error(sb, __func__,
 669                                 "inode %lu: bad block %llu", inode->i_ino,
 670                                 EXT4_I(inode)->i_file_acl);
 671                         error = -EIO;
 672                         goto cleanup;
 673                 }
 674                 /* Find the named attribute. */
 675                 bs->s.base = BHDR(bs->bh);
 676                 bs->s.first = BFIRST(bs->bh);
 677                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 678                 bs->s.here = bs->s.first;
 679                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 680                                               i->name, bs->bh->b_size, 1);
 681                 if (error && error != -ENODATA)
 682                         goto cleanup;
 683                 bs->s.not_found = error;
 684         }
 685         error = 0;
 686
 687 cleanup:
 688         return error;
 689 }
 690
 691 static int
 692 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 693                      struct ext4_xattr_info *i,
 694                      struct ext4_xattr_block_find *bs)
 695 {
 696         struct super_block *sb = inode->i_sb;
 697         struct buffer_head *new_bh = NULL;
 698         struct ext4_xattr_search *s = &bs->s;
 699         struct mb_cache_entry *ce = NULL;
 700         int error = 0;
 701
 702 #define header(x) ((struct ext4_xattr_header *)(x))
 703
 704         if (i->value && i->value_len > sb->s_blocksize)
 705                 return -ENOSPC;
 706         if (s->base) {
 707                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 708                                         bs->bh->b_blocknr);
 709                 error = ext4_journal_get_write_access(handle, bs->bh);
 710                 if (error)
 711                         goto cleanup;
 712                 lock_buffer(bs->bh);
 713
 714                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 715                         if (ce) {
 716                                 mb_cache_entry_free(ce);
 717                                 ce = NULL;
 718                         }
 719                         ea_bdebug(bs->bh, "modifying in-place");
 720                         error = ext4_xattr_set_entry(i, s);
 721                         if (!error) {
 722                                 if (!IS_LAST_ENTRY(s->first))
 723                                         ext4_xattr_rehash(header(s->base),
 724                                                           s->here);
 725                                 ext4_xattr_cache_insert(bs->bh);
 726                         }
 727                         unlock_buffer(bs->bh);
 728                         if (error == -EIO)
 729                                 goto bad_block;
 730                         if (!error)
 731                                 error = ext4_handle_dirty_metadata(handle,
 732                                                                    inode,
 733                                                                    bs->bh);
 734                         if (error)
 735                                 goto cleanup;
 736                         goto inserted;
 737                 } else {
 738                         int offset = (char *)s->here - bs->bh->b_data;
 739
 740                         unlock_buffer(bs->bh);
 741                         jbd2_journal_release_buffer(handle, bs->bh);
 742                         if (ce) {
 743                                 mb_cache_entry_release(ce);
 744                                 ce = NULL;
 745                         }
 746                         ea_bdebug(bs->bh, "cloning");
 747                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 748                         error = -ENOMEM;
 749                         if (s->base == NULL)
 750                                 goto cleanup;
 751                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 752                         s->first = ENTRY(header(s->base)+1);
 753                         header(s->base)->h_refcount = cpu_to_le32(1);
 754                         s->here = ENTRY(s->base + offset);
 755                         s->end = s->base + bs->bh->b_size;
 756                 }
 757         } else {
 758                 /* Allocate a buffer where we construct the new block. */
 759                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 760                 /* assert(header == s->base) */
 761                 error = -ENOMEM;
 762                 if (s->base == NULL)
 763                         goto cleanup;
 764                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 765                 header(s->base)->h_blocks = cpu_to_le32(1);
 766                 header(s->base)->h_refcount = cpu_to_le32(1);
 767                 s->first = ENTRY(header(s->base)+1);
 768                 s->here = ENTRY(header(s->base)+1);
 769                 s->end = s->base + sb->s_blocksize;
 770         }
 771
 772         error = ext4_xattr_set_entry(i, s);
 773         if (error == -EIO)
 774                 goto bad_block;
 775         if (error)
 776                 goto cleanup;
 777         if (!IS_LAST_ENTRY(s->first))
 778                 ext4_xattr_rehash(header(s->base), s->here);
 779
 780 inserted:
 781         if (!IS_LAST_ENTRY(s->first)) {
 782                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 783                 if (new_bh) {
 784                         /* We found an identical block in the cache. */
 785                         if (new_bh == bs->bh)
 786                                 ea_bdebug(new_bh, "keeping");
 787                         else {
 788                                 /* The old block is released after updating
 789                                    the inode. */
 790                                 error = -EDQUOT;
 791                                 if (vfs_dq_alloc_block(inode, 1))
 792                                         goto cleanup;
 793                                 error = ext4_journal_get_write_access(handle,
 794                                                                       new_bh);
 795                                 if (error)
 796                                         goto cleanup_dquot;
 797                                 lock_buffer(new_bh);
 798                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 799                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 800                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 801                                 unlock_buffer(new_bh);
 802                                 error = ext4_handle_dirty_metadata(handle,
 803                                                                    inode,
 804                                                                    new_bh);
 805                                 if (error)
 806                                         goto cleanup_dquot;
 807                         }
 808                         mb_cache_entry_release(ce);
 809                         ce = NULL;
 810                 } else if (bs->bh && s->base == bs->bh->b_data) {
 811                         /* We were modifying this block in-place. */
 812                         ea_bdebug(bs->bh, "keeping this block");
 813                         new_bh = bs->bh;
 814                         get_bh(new_bh);
 815                 } else {
 816                         /* We need to allocate a new block */
 817                         ext4_fsblk_t goal, block;
 818
 819                         goal = ext4_group_first_block_no(sb,
 820                                                 EXT4_I(inode)->i_block_group);
 821
 822                         /* non-extent files can't have physical blocks past 2^32 */
 823                         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
 824                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 825
 826                         block = ext4_new_meta_blocks(handle, inode,
 827                                                   goal, NULL, &error);
 828                         if (error)
 829                                 goto cleanup;
 830
 831                         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
 832                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 833
 834                         ea_idebug(inode, "creating block %d", block);
 835
 836                         new_bh = sb_getblk(sb, block);
 837                         if (!new_bh) {
 838 getblk_failed:
 839                                 ext4_free_blocks(handle, inode, 0, block, 1,
 840                                                  EXT4_FREE_BLOCKS_METADATA);
 841                                 error = -EIO;
 842                                 goto cleanup;
 843                         }
 844                         lock_buffer(new_bh);
 845                         error = ext4_journal_get_create_access(handle, new_bh);
 846                         if (error) {
 847                                 unlock_buffer(new_bh);
 848                                 goto getblk_failed;
 849                         }
 850                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 851                         set_buffer_uptodate(new_bh);
 852                         unlock_buffer(new_bh);
 853                         ext4_xattr_cache_insert(new_bh);
 854                         error = ext4_handle_dirty_metadata(handle,
 855                                                            inode, new_bh);
 856                         if (error)
 857                                 goto cleanup;
 858                 }
 859         }
 860
 861         /* Update the inode. */
 862         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 863
 864         /* Drop the previous xattr block. */
 865         if (bs->bh && bs->bh != new_bh)
 866                 ext4_xattr_release_block(handle, inode, bs->bh);
 867         error = 0;
 868
 869 cleanup:
 870         if (ce)
 871                 mb_cache_entry_release(ce);
 872         brelse(new_bh);
 873         if (!(bs->bh && s->base == bs->bh->b_data))
 874                 kfree(s->base);
 875
 876         return error;
 877
 878 cleanup_dquot:
 879         vfs_dq_free_block(inode, 1);
 880         goto cleanup;
 881
 882 bad_block:
 883         ext4_error(inode->i_sb, __func__,
 884                    "inode %lu: bad block %llu", inode->i_ino,
 885                    EXT4_I(inode)->i_file_acl);
 886         goto cleanup;
 887
 888 #undef header
 889 }
 890
 891 struct ext4_xattr_ibody_find {
 892         struct ext4_xattr_search s;
 893         struct ext4_iloc iloc;
 894 };
 895
 896 static int
 897 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 898                       struct ext4_xattr_ibody_find *is)
 899 {
 900         struct ext4_xattr_ibody_header *header;
 901         struct ext4_inode *raw_inode;
 902         int error;
 903
 904         if (EXT4_I(inode)->i_extra_isize == 0)
 905                 return 0;
 906         raw_inode = ext4_raw_inode(&is->iloc);
 907         header = IHDR(inode, raw_inode);
 908         is->s.base = is->s.first = IFIRST(header);
 909         is->s.here = is->s.first;
 910         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 911         if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
 912                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 913                 if (error)
 914                         return error;
 915                 /* Find the named attribute. */
 916                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 917                                               i->name, is->s.end -
 918                                               (void *)is->s.base, 0);
 919                 if (error && error != -ENODATA)
 920                         return error;
 921                 is->s.not_found = error;
 922         }
 923         return 0;
 924 }
 925
 926 static int
 927 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 928                      struct ext4_xattr_info *i,
 929                      struct ext4_xattr_ibody_find *is)
 930 {
 931         struct ext4_xattr_ibody_header *header;
 932         struct ext4_xattr_search *s = &is->s;
 933         int error;
 934
 935         if (EXT4_I(inode)->i_extra_isize == 0)
 936                 return -ENOSPC;
 937         error = ext4_xattr_set_entry(i, s);
 938         if (error)
 939                 return error;
 940         header = IHDR(inode, ext4_raw_inode(&is->iloc));
 941         if (!IS_LAST_ENTRY(s->first)) {
 942                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 943                 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
 944         } else {
 945                 header->h_magic = cpu_to_le32(0);
 946                 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
 947         }
 948         return 0;
 949 }
 950
 951 /*
 952  * ext4_xattr_set_handle()
 953  *
 954  * Create, replace or remove an extended attribute for this inode. Buffer
 955  * is NULL to remove an existing extended attribute, and non-NULL to
 956  * either replace an existing extended attribute, or create a new extended
 957  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
 958  * specify that an extended attribute must exist and must not exist
 959  * previous to the call, respectively.
 960  *
 961  * Returns 0, or a negative error number on failure.
 962  */
 963 int
 964 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 965                       const char *name, const void *value, size_t value_len,
 966                       int flags)
 967 {
 968         struct ext4_xattr_info i = {
 969                 .name_index = name_index,
 970                 .name = name,
 971                 .value = value,
 972                 .value_len = value_len,
 973
 974         };
 975         struct ext4_xattr_ibody_find is = {
 976                 .s = { .not_found = -ENODATA, },
 977         };
 978         struct ext4_xattr_block_find bs = {
 979                 .s = { .not_found = -ENODATA, },
 980         };
 981         unsigned long no_expand;
 982         int error;
 983
 984         if (!name)
 985                 return -EINVAL;
 986         if (strlen(name) > 255)
 987                 return -ERANGE;
 988         down_write(&EXT4_I(inode)->xattr_sem);
 989         no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;
 990         EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
 991
 992         error = ext4_get_inode_loc(inode, &is.iloc);
 993         if (error)
 994                 goto cleanup;
 995
 996         error = ext4_journal_get_write_access(handle, is.iloc.bh);
 997         if (error)
 998                 goto cleanup;
 999
1000         if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
1001                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1002                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1003                 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
1004         }
1005
1006         error = ext4_xattr_ibody_find(inode, &i, &is);
1007         if (error)
1008                 goto cleanup;
1009         if (is.s.not_found)
1010                 error = ext4_xattr_block_find(inode, &i, &bs);
1011         if (error)
1012                 goto cleanup;
1013         if (is.s.not_found && bs.s.not_found) {
1014                 error = -ENODATA;
1015                 if (flags & XATTR_REPLACE)
1016                         goto cleanup;
1017                 error = 0;
1018                 if (!value)
1019                         goto cleanup;
1020         } else {
1021                 error = -EEXIST;
1022                 if (flags & XATTR_CREATE)
1023                         goto cleanup;
1024         }
1025         if (!value) {
1026                 if (!is.s.not_found)
1027                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1028                 else if (!bs.s.not_found)
1029                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1030         } else {
1031                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1032                 if (!error && !bs.s.not_found) {
1033                         i.value = NULL;
1034                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1035                 } else if (error == -ENOSPC) {
1036                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1037                                 error = ext4_xattr_block_find(inode, &i, &bs);
1038                                 if (error)
1039                                         goto cleanup;
1040                         }
1041                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1042                         if (error)
1043                                 goto cleanup;
1044                         if (!is.s.not_found) {
1045                                 i.value = NULL;
1046                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1047                                                              &is);
1048                         }
1049                 }
1050         }
1051         if (!error) {
1052                 ext4_xattr_update_super_block(handle, inode->i_sb);
1053                 inode->i_ctime = ext4_current_time(inode);
1054                 if (!value)
1055                         EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1056                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1057                 /*
1058                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1059                  * error != 0.
1060                  */
1061                 is.iloc.bh = NULL;
1062                 if (IS_SYNC(inode))
1063                         ext4_handle_sync(handle);
1064         }
1065
1066 cleanup:
1067         brelse(is.iloc.bh);
1068         brelse(bs.bh);
1069         if (no_expand == 0)
1070                 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1071         up_write(&EXT4_I(inode)->xattr_sem);
1072         return error;
1073 }
1074
1075 /*
1076  * ext4_xattr_set()
1077  *
1078  * Like ext4_xattr_set_handle, but start from an inode. This extended
1079  * attribute modification is a filesystem transaction by itself.
1080  *
1081  * Returns 0, or a negative error number on failure.
1082  */
1083 int
1084 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1085                const void *value, size_t value_len, int flags)
1086 {
1087         handle_t *handle;
1088         int error, retries = 0;
1089
1090 retry:
1091         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1092         if (IS_ERR(handle)) {
1093                 error = PTR_ERR(handle);
1094         } else {
1095                 int error2;
1096
1097                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1098                                               value, value_len, flags);
1099                 error2 = ext4_journal_stop(handle);
1100                 if (error == -ENOSPC &&
1101                     ext4_should_retry_alloc(inode->i_sb, &retries))
1102                         goto retry;
1103                 if (error == 0)
1104                         error = error2;
1105         }
1106
1107         return error;
1108 }
1109
1110 /*
1111  * Shift the EA entries in the inode to create space for the increased
1112  * i_extra_isize.
1113  */
1114 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1115                                      int value_offs_shift, void *to,
1116                                      void *from, size_t n, int blocksize)
1117 {
1118         struct ext4_xattr_entry *last = entry;
1119         int new_offs;
1120
1121         /* Adjust the value offsets of the entries */
1122         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1123                 if (!last->e_value_block && last->e_value_size) {
1124                         new_offs = le16_to_cpu(last->e_value_offs) +
1125                                                         value_offs_shift;
1126                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1127                                  > blocksize);
1128                         last->e_value_offs = cpu_to_le16(new_offs);
1129                 }
1130         }
1131         /* Shift the entries by n bytes */
1132         memmove(to, from, n);
1133 }
1134
1135 /*
1136  * Expand an inode by new_extra_isize bytes when EAs are present.
1137  * Returns 0 on success or negative error number on failure.
1138  */
1139 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1140                                struct ext4_inode *raw_inode, handle_t *handle)
1141 {
1142         struct ext4_xattr_ibody_header *header;
1143         struct ext4_xattr_entry *entry, *last, *first;
1144         struct buffer_head *bh = NULL;
1145         struct ext4_xattr_ibody_find *is = NULL;
1146         struct ext4_xattr_block_find *bs = NULL;
1147         char *buffer = NULL, *b_entry_name = NULL;
1148         size_t min_offs, free;
1149         int total_ino, total_blk;
1150         void *base, *start, *end;
1151         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1152         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1153
1154         down_write(&EXT4_I(inode)->xattr_sem);
1155 retry:
1156         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1157                 up_write(&EXT4_I(inode)->xattr_sem);
1158                 return 0;
1159         }
1160
1161         header = IHDR(inode, raw_inode);
1162         entry = IFIRST(header);
1163
1164         /*
1165          * Check if enough free space is available in the inode to shift the
1166          * entries ahead by new_extra_isize.
1167          */
1168
1169         base = start = entry;
1170         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1171         min_offs = end - base;
1172         last = entry;
1173         total_ino = sizeof(struct ext4_xattr_ibody_header);
1174
1175         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1176         if (free >= new_extra_isize) {
1177                 entry = IFIRST(header);
1178                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1179                                 - new_extra_isize, (void *)raw_inode +
1180                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1181                                 (void *)header, total_ino,
1182                                 inode->i_sb->s_blocksize);
1183                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1184                 error = 0;
1185                 goto cleanup;
1186         }
1187
1188         /*
1189          * Enough free space isn't available in the inode, check if
1190          * EA block can hold new_extra_isize bytes.
1191          */
1192         if (EXT4_I(inode)->i_file_acl) {
1193                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1194                 error = -EIO;
1195                 if (!bh)
1196                         goto cleanup;
1197                 if (ext4_xattr_check_block(bh)) {
1198                         ext4_error(inode->i_sb, __func__,
1199                                 "inode %lu: bad block %llu", inode->i_ino,
1200                                 EXT4_I(inode)->i_file_acl);
1201                         error = -EIO;
1202                         goto cleanup;
1203                 }
1204                 base = BHDR(bh);
1205                 first = BFIRST(bh);
1206                 end = bh->b_data + bh->b_size;
1207                 min_offs = end - base;
1208                 free = ext4_xattr_free_space(first, &min_offs, base,
1209                                              &total_blk);
1210                 if (free < new_extra_isize) {
1211                         if (!tried_min_extra_isize && s_min_extra_isize) {
1212                                 tried_min_extra_isize++;
1213                                 new_extra_isize = s_min_extra_isize;
1214                                 brelse(bh);
1215                                 goto retry;
1216                         }
1217                         error = -1;
1218                         goto cleanup;
1219                 }
1220         } else {
1221                 free = inode->i_sb->s_blocksize;
1222         }
1223
1224         while (new_extra_isize > 0) {
1225                 size_t offs, size, entry_size;
1226                 struct ext4_xattr_entry *small_entry = NULL;
1227                 struct ext4_xattr_info i = {
1228                         .value = NULL,
1229                         .value_len = 0,
1230                 };
1231                 unsigned int total_size;  /* EA entry size + value size */
1232                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1233                 unsigned int min_total_size = ~0U;
1234
1235                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1236                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1237                 if (!is || !bs) {
1238                         error = -ENOMEM;
1239                         goto cleanup;
1240                 }
1241
1242                 is->s.not_found = -ENODATA;
1243                 bs->s.not_found = -ENODATA;
1244                 is->iloc.bh = NULL;
1245                 bs->bh = NULL;
1246
1247                 last = IFIRST(header);
1248                 /* Find the entry best suited to be pushed into EA block */
1249                 entry = NULL;
1250                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1251                         total_size =
1252                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1253                                         EXT4_XATTR_LEN(last->e_name_len);
1254                         if (total_size <= free && total_size < min_total_size) {
1255                                 if (total_size < new_extra_isize) {
1256                                         small_entry = last;
1257                                 } else {
1258                                         entry = last;
1259                                         min_total_size = total_size;
1260                                 }
1261                         }
1262                 }
1263
1264                 if (entry == NULL) {
1265                         if (small_entry) {
1266                                 entry = small_entry;
1267                         } else {
1268                                 if (!tried_min_extra_isize &&
1269                                     s_min_extra_isize) {
1270                                         tried_min_extra_isize++;
1271                                         new_extra_isize = s_min_extra_isize;
1272                                         goto retry;
1273                                 }
1274                                 error = -1;
1275                                 goto cleanup;
1276                         }
1277                 }
1278                 offs = le16_to_cpu(entry->e_value_offs);
1279                 size = le32_to_cpu(entry->e_value_size);
1280                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1281                 i.name_index = entry->e_name_index,
1282                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1283                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1284                 if (!buffer || !b_entry_name) {
1285                         error = -ENOMEM;
1286                         goto cleanup;
1287                 }
1288                 /* Save the entry name and the entry value */
1289                 memcpy(buffer, (void *)IFIRST(header) + offs,
1290                        EXT4_XATTR_SIZE(size));
1291                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1292                 b_entry_name[entry->e_name_len] = '\0';
1293                 i.name = b_entry_name;
1294
1295                 error = ext4_get_inode_loc(inode, &is->iloc);
1296                 if (error)
1297                         goto cleanup;
1298
1299                 error = ext4_xattr_ibody_find(inode, &i, is);
1300                 if (error)
1301                         goto cleanup;
1302
1303                 /* Remove the chosen entry from the inode */
1304                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1305
1306                 entry = IFIRST(header);
1307                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1308                         shift_bytes = new_extra_isize;
1309                 else
1310                         shift_bytes = entry_size + size;
1311                 /* Adjust the offsets and shift the remaining entries ahead */
1312                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1313                         shift_bytes, (void *)raw_inode +
1314                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1315                         (void *)header, total_ino - entry_size,
1316                         inode->i_sb->s_blocksize);
1317
1318                 extra_isize += shift_bytes;
1319                 new_extra_isize -= shift_bytes;
1320                 EXT4_I(inode)->i_extra_isize = extra_isize;
1321
1322                 i.name = b_entry_name;
1323                 i.value = buffer;
1324                 i.value_len = size;
1325                 error = ext4_xattr_block_find(inode, &i, bs);
1326                 if (error)
1327                         goto cleanup;
1328
1329                 /* Add entry which was removed from the inode into the block */
1330                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1331                 if (error)
1332                         goto cleanup;
1333                 kfree(b_entry_name);
1334                 kfree(buffer);
1335                 b_entry_name = NULL;
1336                 buffer = NULL;
1337                 brelse(is->iloc.bh);
1338                 kfree(is);
1339                 kfree(bs);
1340         }
1341         brelse(bh);
1342         up_write(&EXT4_I(inode)->xattr_sem);
1343         return 0;
1344
1345 cleanup:
1346         kfree(b_entry_name);
1347         kfree(buffer);
1348         if (is)
1349                 brelse(is->iloc.bh);
1350         kfree(is);
1351         kfree(bs);
1352         brelse(bh);
1353         up_write(&EXT4_I(inode)->xattr_sem);
1354         return error;
1355 }
1356
1357
1358
1359 /*
1360  * ext4_xattr_delete_inode()
1361  *
1362  * Free extended attribute resources associated with this inode. This
1363  * is called immediately before an inode is freed. We have exclusive
1364  * access to the inode.
1365  */
1366 void
1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1368 {
1369         struct buffer_head *bh = NULL;
1370
1371         if (!EXT4_I(inode)->i_file_acl)
1372                 goto cleanup;
1373         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1374         if (!bh) {
1375                 ext4_error(inode->i_sb, __func__,
1376                         "inode %lu: block %llu read error", inode->i_ino,
1377                         EXT4_I(inode)->i_file_acl);
1378                 goto cleanup;
1379         }
1380         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1381             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1382                 ext4_error(inode->i_sb, __func__,
1383                         "inode %lu: bad block %llu", inode->i_ino,
1384                         EXT4_I(inode)->i_file_acl);
1385                 goto cleanup;
1386         }
1387         ext4_xattr_release_block(handle, inode, bh);
1388         EXT4_I(inode)->i_file_acl = 0;
1389
1390 cleanup:
1391         brelse(bh);
1392 }
1393
1394 /*
1395  * ext4_xattr_put_super()
1396  *
1397  * This is called when a file system is unmounted.
1398  */
1399 void
1400 ext4_xattr_put_super(struct super_block *sb)
1401 {
1402         mb_cache_shrink(sb->s_bdev);
1403 }
1404
1405 /*
1406  * ext4_xattr_cache_insert()
1407  *
1408  * Create a new entry in the extended attribute cache, and insert
1409  * it unless such an entry is already in the cache.
1410  *
1411  * Returns 0, or a negative error number on failure.
1412  */
1413 static void
1414 ext4_xattr_cache_insert(struct buffer_head *bh)
1415 {
1416         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1417         struct mb_cache_entry *ce;
1418         int error;
1419
1420         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1421         if (!ce) {
1422                 ea_bdebug(bh, "out of memory");
1423                 return;
1424         }
1425         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1426         if (error) {
1427                 mb_cache_entry_free(ce);
1428                 if (error == -EBUSY) {
1429                         ea_bdebug(bh, "already in cache");
1430                         error = 0;
1431                 }
1432         } else {
1433                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1434                 mb_cache_entry_release(ce);
1435         }
1436 }
1437
1438 /*
1439  * ext4_xattr_cmp()
1440  *
1441  * Compare two extended attribute blocks for equality.
1442  *
1443  * Returns 0 if the blocks are equal, 1 if they differ, and
1444  * a negative error number on errors.
1445  */
1446 static int
1447 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1448                struct ext4_xattr_header *header2)
1449 {
1450         struct ext4_xattr_entry *entry1, *entry2;
1451
1452         entry1 = ENTRY(header1+1);
1453         entry2 = ENTRY(header2+1);
1454         while (!IS_LAST_ENTRY(entry1)) {
1455                 if (IS_LAST_ENTRY(entry2))
1456                         return 1;
1457                 if (entry1->e_hash != entry2->e_hash ||
1458                     entry1->e_name_index != entry2->e_name_index ||
1459                     entry1->e_name_len != entry2->e_name_len ||
1460                     entry1->e_value_size != entry2->e_value_size ||
1461                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1462                         return 1;
1463                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1464                         return -EIO;
1465                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1466                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1467                            le32_to_cpu(entry1->e_value_size)))
1468                         return 1;
1469
1470                 entry1 = EXT4_XATTR_NEXT(entry1);
1471                 entry2 = EXT4_XATTR_NEXT(entry2);
1472         }
1473         if (!IS_LAST_ENTRY(entry2))
1474                 return 1;
1475         return 0;
1476 }
1477
1478 /*
1479  * ext4_xattr_cache_find()
1480  *
1481  * Find an identical extended attribute block.
1482  *
1483  * Returns a pointer to the block found, or NULL if such a block was
1484  * not found or an error occurred.
1485  */
1486 static struct buffer_head *
1487 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1488                       struct mb_cache_entry **pce)
1489 {
1490         __u32 hash = le32_to_cpu(header->h_hash);
1491         struct mb_cache_entry *ce;
1492
1493         if (!header->h_hash)
1494                 return NULL;  /* never share */
1495         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1496 again:
1497         ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1498                                        inode->i_sb->s_bdev, hash);
1499         while (ce) {
1500                 struct buffer_head *bh;
1501
1502                 if (IS_ERR(ce)) {
1503                         if (PTR_ERR(ce) == -EAGAIN)
1504                                 goto again;
1505                         break;
1506                 }
1507                 bh = sb_bread(inode->i_sb, ce->e_block);
1508                 if (!bh) {
1509                         ext4_error(inode->i_sb, __func__,
1510                                 "inode %lu: block %lu read error",
1511                                 inode->i_ino, (unsigned long) ce->e_block);
1512                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1513                                 EXT4_XATTR_REFCOUNT_MAX) {
1514                         ea_idebug(inode, "block %lu refcount %d>=%d",
1515                                   (unsigned long) ce->e_block,
1516                                   le32_to_cpu(BHDR(bh)->h_refcount),
1517                                           EXT4_XATTR_REFCOUNT_MAX);
1518                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1519                         *pce = ce;
1520                         return bh;
1521                 }
1522                 brelse(bh);
1523                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1524         }
1525         return NULL;
1526 }
1527
1528 #define NAME_HASH_SHIFT 5
1529 #define VALUE_HASH_SHIFT 16
1530
1531 /*
1532  * ext4_xattr_hash_entry()
1533  *
1534  * Compute the hash of an extended attribute.
1535  */
1536 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1537                                          struct ext4_xattr_entry *entry)
1538 {
1539         __u32 hash = 0;
1540         char *name = entry->e_name;
1541         int n;
1542
1543         for (n = 0; n < entry->e_name_len; n++) {
1544                 hash = (hash << NAME_HASH_SHIFT) ^
1545                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1546                        *name++;
1547         }
1548
1549         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1550                 __le32 *value = (__le32 *)((char *)header +
1551                         le16_to_cpu(entry->e_value_offs));
1552                 for (n = (le32_to_cpu(entry->e_value_size) +
1553                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1554                         hash = (hash << VALUE_HASH_SHIFT) ^
1555                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1556                                le32_to_cpu(*value++);
1557                 }
1558         }
1559         entry->e_hash = cpu_to_le32(hash);
1560 }
1561
1562 #undef NAME_HASH_SHIFT
1563 #undef VALUE_HASH_SHIFT
1564
1565 #define BLOCK_HASH_SHIFT 16
1566
1567 /*
1568  * ext4_xattr_rehash()
1569  *
1570  * Re-compute the extended attribute hash value after an entry has changed.
1571  */
1572 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1573                               struct ext4_xattr_entry *entry)
1574 {
1575         struct ext4_xattr_entry *here;
1576         __u32 hash = 0;
1577
1578         ext4_xattr_hash_entry(header, entry);
1579         here = ENTRY(header+1);
1580         while (!IS_LAST_ENTRY(here)) {
1581                 if (!here->e_hash) {
1582                         /* Block is not shared if an entry's hash value == 0 */
1583                         hash = 0;
1584                         break;
1585                 }
1586                 hash = (hash << BLOCK_HASH_SHIFT) ^
1587                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1588                        le32_to_cpu(here->e_hash);
1589                 here = EXT4_XATTR_NEXT(here);
1590         }
1591         header->h_hash = cpu_to_le32(hash);
1592 }
1593
1594 #undef BLOCK_HASH_SHIFT
1595
1596 int __init
1597 init_ext4_xattr(void)
1598 {
1599         ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1600                 sizeof(struct mb_cache_entry) +
1601                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1602         if (!ext4_xattr_cache)
1603                 return -ENOMEM;
1604         return 0;
1605 }
1606
1607 void
1608 exit_ext4_xattr(void)
1609 {
1610         if (ext4_xattr_cache)
1611                 mb_cache_destroy(ext4_xattr_cache);
1612         ext4_xattr_cache = NULL;
1613 }