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 const struct xattr_handler *ext4_xattr_handler_map[] = {
 101         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 103         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
 104         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
 105 #endif
 106         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 107 #ifdef CONFIG_EXT4_FS_SECURITY
 108         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 109 #endif
 110 };
 111
 112 const struct xattr_handler *ext4_xattr_handlers[] = {
 113         &ext4_xattr_user_handler,
 114         &ext4_xattr_trusted_handler,
 115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 116         &ext4_xattr_acl_access_handler,
 117         &ext4_xattr_acl_default_handler,
 118 #endif
 119 #ifdef CONFIG_EXT4_FS_SECURITY
 120         &ext4_xattr_security_handler,
 121 #endif
 122         NULL
 123 };
 124
 125 static inline const struct xattr_handler *
 126 ext4_xattr_handler(int name_index)
 127 {
 128         const 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:
 231                 EXT4_ERROR_INODE(inode, "bad block %llu",
 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_test_inode_state(inode, 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                 const 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(inode, "bad block %llu",
 375                                  EXT4_I(inode)->i_file_acl);
 376                 error = -EIO;
 377                 goto cleanup;
 378         }
 379         ext4_xattr_cache_insert(bh);
 380         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 381
 382 cleanup:
 383         brelse(bh);
 384
 385         return error;
 386 }
 387
 388 static int
 389 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 390 {
 391         struct inode *inode = dentry->d_inode;
 392         struct ext4_xattr_ibody_header *header;
 393         struct ext4_inode *raw_inode;
 394         struct ext4_iloc iloc;
 395         void *end;
 396         int error;
 397
 398         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 399                 return 0;
 400         error = ext4_get_inode_loc(inode, &iloc);
 401         if (error)
 402                 return error;
 403         raw_inode = ext4_raw_inode(&iloc);
 404         header = IHDR(inode, raw_inode);
 405         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 406         error = ext4_xattr_check_names(IFIRST(header), end);
 407         if (error)
 408                 goto cleanup;
 409         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 410                                         buffer, buffer_size);
 411
 412 cleanup:
 413         brelse(iloc.bh);
 414         return error;
 415 }
 416
 417 /*
 418  * ext4_xattr_list()
 419  *
 420  * Copy a list of attribute names into the buffer
 421  * provided, or compute the buffer size required.
 422  * Buffer is NULL to compute the size of the buffer required.
 423  *
 424  * Returns a negative error number on failure, or the number of bytes
 425  * used / required on success.
 426  */
 427 static int
 428 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 429 {
 430         int ret, ret2;
 431
 432         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 433         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 434         if (ret < 0)
 435                 goto errout;
 436         if (buffer) {
 437                 buffer += ret;
 438                 buffer_size -= ret;
 439         }
 440         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 441         if (ret < 0)
 442                 goto errout;
 443         ret += ret2;
 444 errout:
 445         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 446         return ret;
 447 }
 448
 449 /*
 450  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 451  * not set, set it.
 452  */
 453 static void ext4_xattr_update_super_block(handle_t *handle,
 454                                           struct super_block *sb)
 455 {
 456         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 457                 return;
 458
 459         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 460                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 461                 ext4_handle_dirty_super(handle, sb);
 462         }
 463 }
 464
 465 /*
 466  * Release the xattr block BH: If the reference count is > 1, decrement
 467  * it; otherwise free the block.
 468  */
 469 static void
 470 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 471                          struct buffer_head *bh)
 472 {
 473         struct mb_cache_entry *ce = NULL;
 474         int error = 0;
 475
 476         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 477         error = ext4_journal_get_write_access(handle, bh);
 478         if (error)
 479                 goto out;
 480
 481         lock_buffer(bh);
 482         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 483                 ea_bdebug(bh, "refcount now=0; freeing");
 484                 if (ce)
 485                         mb_cache_entry_free(ce);
 486                 get_bh(bh);
 487                 ext4_free_blocks(handle, inode, bh, 0, 1,
 488                                  EXT4_FREE_BLOCKS_METADATA |
 489                                  EXT4_FREE_BLOCKS_FORGET);
 490         } else {
 491                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 492                 error = ext4_handle_dirty_metadata(handle, inode, bh);
 493                 if (IS_SYNC(inode))
 494                         ext4_handle_sync(handle);
 495                 dquot_free_block(inode, 1);
 496                 ea_bdebug(bh, "refcount now=%d; releasing",
 497                           le32_to_cpu(BHDR(bh)->h_refcount));
 498                 if (ce)
 499                         mb_cache_entry_release(ce);
 500         }
 501         unlock_buffer(bh);
 502 out:
 503         ext4_std_error(inode->i_sb, error);
 504         return;
 505 }
 506
 507 /*
 508  * Find the available free space for EAs. This also returns the total number of
 509  * bytes used by EA entries.
 510  */
 511 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
 512                                     size_t *min_offs, void *base, int *total)
 513 {
 514         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 515                 *total += EXT4_XATTR_LEN(last->e_name_len);
 516                 if (!last->e_value_block && last->e_value_size) {
 517                         size_t offs = le16_to_cpu(last->e_value_offs);
 518                         if (offs < *min_offs)
 519                                 *min_offs = offs;
 520                 }
 521         }
 522         return (*min_offs - ((void *)last - base) - sizeof(__u32));
 523 }
 524
 525 struct ext4_xattr_info {
 526         int name_index;
 527         const char *name;
 528         const void *value;
 529         size_t value_len;
 530 };
 531
 532 struct ext4_xattr_search {
 533         struct ext4_xattr_entry *first;
 534         void *base;
 535         void *end;
 536         struct ext4_xattr_entry *here;
 537         int not_found;
 538 };
 539
 540 static int
 541 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
 542 {
 543         struct ext4_xattr_entry *last;
 544         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 545
 546         /* Compute min_offs and last. */
 547         last = s->first;
 548         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 549                 if (!last->e_value_block && last->e_value_size) {
 550                         size_t offs = le16_to_cpu(last->e_value_offs);
 551                         if (offs < min_offs)
 552                                 min_offs = offs;
 553                 }
 554         }
 555         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 556         if (!s->not_found) {
 557                 if (!s->here->e_value_block && s->here->e_value_size) {
 558                         size_t size = le32_to_cpu(s->here->e_value_size);
 559                         free += EXT4_XATTR_SIZE(size);
 560                 }
 561                 free += EXT4_XATTR_LEN(name_len);
 562         }
 563         if (i->value) {
 564                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
 565                     free < EXT4_XATTR_LEN(name_len) +
 566                            EXT4_XATTR_SIZE(i->value_len))
 567                         return -ENOSPC;
 568         }
 569
 570         if (i->value && s->not_found) {
 571                 /* Insert the new name. */
 572                 size_t size = EXT4_XATTR_LEN(name_len);
 573                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
 574                 memmove((void *)s->here + size, s->here, rest);
 575                 memset(s->here, 0, size);
 576                 s->here->e_name_index = i->name_index;
 577                 s->here->e_name_len = name_len;
 578                 memcpy(s->here->e_name, i->name, name_len);
 579         } else {
 580                 if (!s->here->e_value_block && s->here->e_value_size) {
 581                         void *first_val = s->base + min_offs;
 582                         size_t offs = le16_to_cpu(s->here->e_value_offs);
 583                         void *val = s->base + offs;
 584                         size_t size = EXT4_XATTR_SIZE(
 585                                 le32_to_cpu(s->here->e_value_size));
 586
 587                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
 588                                 /* The old and the new value have the same
 589                                    size. Just replace. */
 590                                 s->here->e_value_size =
 591                                         cpu_to_le32(i->value_len);
 592                                 memset(val + size - EXT4_XATTR_PAD, 0,
 593                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
 594                                 memcpy(val, i->value, i->value_len);
 595                                 return 0;
 596                         }
 597
 598                         /* Remove the old value. */
 599                         memmove(first_val + size, first_val, val - first_val);
 600                         memset(first_val, 0, size);
 601                         s->here->e_value_size = 0;
 602                         s->here->e_value_offs = 0;
 603                         min_offs += size;
 604
 605                         /* Adjust all value offsets. */
 606                         last = s->first;
 607                         while (!IS_LAST_ENTRY(last)) {
 608                                 size_t o = le16_to_cpu(last->e_value_offs);
 609                                 if (!last->e_value_block &&
 610                                     last->e_value_size && o < offs)
 611                                         last->e_value_offs =
 612                                                 cpu_to_le16(o + size);
 613                                 last = EXT4_XATTR_NEXT(last);
 614                         }
 615                 }
 616                 if (!i->value) {
 617                         /* Remove the old name. */
 618                         size_t size = EXT4_XATTR_LEN(name_len);
 619                         last = ENTRY((void *)last - size);
 620                         memmove(s->here, (void *)s->here + size,
 621                                 (void *)last - (void *)s->here + sizeof(__u32));
 622                         memset(last, 0, size);
 623                 }
 624         }
 625
 626         if (i->value) {
 627                 /* Insert the new value. */
 628                 s->here->e_value_size = cpu_to_le32(i->value_len);
 629                 if (i->value_len) {
 630                         size_t size = EXT4_XATTR_SIZE(i->value_len);
 631                         void *val = s->base + min_offs - size;
 632                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
 633                         memset(val + size - EXT4_XATTR_PAD, 0,
 634                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
 635                         memcpy(val, i->value, i->value_len);
 636                 }
 637         }
 638         return 0;
 639 }
 640
 641 struct ext4_xattr_block_find {
 642         struct ext4_xattr_search s;
 643         struct buffer_head *bh;
 644 };
 645
 646 static int
 647 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
 648                       struct ext4_xattr_block_find *bs)
 649 {
 650         struct super_block *sb = inode->i_sb;
 651         int error;
 652
 653         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
 654                   i->name_index, i->name, i->value, (long)i->value_len);
 655
 656         if (EXT4_I(inode)->i_file_acl) {
 657                 /* The inode already has an extended attribute block. */
 658                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
 659                 error = -EIO;
 660                 if (!bs->bh)
 661                         goto cleanup;
 662                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
 663                         atomic_read(&(bs->bh->b_count)),
 664                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
 665                 if (ext4_xattr_check_block(bs->bh)) {
 666                         EXT4_ERROR_INODE(inode, "bad block %llu",
 667                                          EXT4_I(inode)->i_file_acl);
 668                         error = -EIO;
 669                         goto cleanup;
 670                 }
 671                 /* Find the named attribute. */
 672                 bs->s.base = BHDR(bs->bh);
 673                 bs->s.first = BFIRST(bs->bh);
 674                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
 675                 bs->s.here = bs->s.first;
 676                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
 677                                               i->name, bs->bh->b_size, 1);
 678                 if (error && error != -ENODATA)
 679                         goto cleanup;
 680                 bs->s.not_found = error;
 681         }
 682         error = 0;
 683
 684 cleanup:
 685         return error;
 686 }
 687
 688 static int
 689 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 690                      struct ext4_xattr_info *i,
 691                      struct ext4_xattr_block_find *bs)
 692 {
 693         struct super_block *sb = inode->i_sb;
 694         struct buffer_head *new_bh = NULL;
 695         struct ext4_xattr_search *s = &bs->s;
 696         struct mb_cache_entry *ce = NULL;
 697         int error = 0;
 698
 699 #define header(x) ((struct ext4_xattr_header *)(x))
 700
 701         if (i->value && i->value_len > sb->s_blocksize)
 702                 return -ENOSPC;
 703         if (s->base) {
 704                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
 705                                         bs->bh->b_blocknr);
 706                 error = ext4_journal_get_write_access(handle, bs->bh);
 707                 if (error)
 708                         goto cleanup;
 709                 lock_buffer(bs->bh);
 710
 711                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
 712                         if (ce) {
 713                                 mb_cache_entry_free(ce);
 714                                 ce = NULL;
 715                         }
 716                         ea_bdebug(bs->bh, "modifying in-place");
 717                         error = ext4_xattr_set_entry(i, s);
 718                         if (!error) {
 719                                 if (!IS_LAST_ENTRY(s->first))
 720                                         ext4_xattr_rehash(header(s->base),
 721                                                           s->here);
 722                                 ext4_xattr_cache_insert(bs->bh);
 723                         }
 724                         unlock_buffer(bs->bh);
 725                         if (error == -EIO)
 726                                 goto bad_block;
 727                         if (!error)
 728                                 error = ext4_handle_dirty_metadata(handle,
 729                                                                    inode,
 730                                                                    bs->bh);
 731                         if (error)
 732                                 goto cleanup;
 733                         goto inserted;
 734                 } else {
 735                         int offset = (char *)s->here - bs->bh->b_data;
 736
 737                         unlock_buffer(bs->bh);
 738                         jbd2_journal_release_buffer(handle, bs->bh);
 739                         if (ce) {
 740                                 mb_cache_entry_release(ce);
 741                                 ce = NULL;
 742                         }
 743                         ea_bdebug(bs->bh, "cloning");
 744                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
 745                         error = -ENOMEM;
 746                         if (s->base == NULL)
 747                                 goto cleanup;
 748                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 749                         s->first = ENTRY(header(s->base)+1);
 750                         header(s->base)->h_refcount = cpu_to_le32(1);
 751                         s->here = ENTRY(s->base + offset);
 752                         s->end = s->base + bs->bh->b_size;
 753                 }
 754         } else {
 755                 /* Allocate a buffer where we construct the new block. */
 756                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
 757                 /* assert(header == s->base) */
 758                 error = -ENOMEM;
 759                 if (s->base == NULL)
 760                         goto cleanup;
 761                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 762                 header(s->base)->h_blocks = cpu_to_le32(1);
 763                 header(s->base)->h_refcount = cpu_to_le32(1);
 764                 s->first = ENTRY(header(s->base)+1);
 765                 s->here = ENTRY(header(s->base)+1);
 766                 s->end = s->base + sb->s_blocksize;
 767         }
 768
 769         error = ext4_xattr_set_entry(i, s);
 770         if (error == -EIO)
 771                 goto bad_block;
 772         if (error)
 773                 goto cleanup;
 774         if (!IS_LAST_ENTRY(s->first))
 775                 ext4_xattr_rehash(header(s->base), s->here);
 776
 777 inserted:
 778         if (!IS_LAST_ENTRY(s->first)) {
 779                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
 780                 if (new_bh) {
 781                         /* We found an identical block in the cache. */
 782                         if (new_bh == bs->bh)
 783                                 ea_bdebug(new_bh, "keeping");
 784                         else {
 785                                 /* The old block is released after updating
 786                                    the inode. */
 787                                 error = dquot_alloc_block(inode, 1);
 788                                 if (error)
 789                                         goto cleanup;
 790                                 error = ext4_journal_get_write_access(handle,
 791                                                                       new_bh);
 792                                 if (error)
 793                                         goto cleanup_dquot;
 794                                 lock_buffer(new_bh);
 795                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
 796                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
 797                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
 798                                 unlock_buffer(new_bh);
 799                                 error = ext4_handle_dirty_metadata(handle,
 800                                                                    inode,
 801                                                                    new_bh);
 802                                 if (error)
 803                                         goto cleanup_dquot;
 804                         }
 805                         mb_cache_entry_release(ce);
 806                         ce = NULL;
 807                 } else if (bs->bh && s->base == bs->bh->b_data) {
 808                         /* We were modifying this block in-place. */
 809                         ea_bdebug(bs->bh, "keeping this block");
 810                         new_bh = bs->bh;
 811                         get_bh(new_bh);
 812                 } else {
 813                         /* We need to allocate a new block */
 814                         ext4_fsblk_t goal, block;
 815
 816                         goal = ext4_group_first_block_no(sb,
 817                                                 EXT4_I(inode)->i_block_group);
 818
 819                         /* non-extent files can't have physical blocks past 2^32 */
 820                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 821                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 822
 823                         block = ext4_new_meta_blocks(handle, inode,
 824                                                   goal, NULL, &error);
 825                         if (error)
 826                                 goto cleanup;
 827
 828                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 829                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 830
 831                         ea_idebug(inode, "creating block %d", block);
 832
 833                         new_bh = sb_getblk(sb, block);
 834                         if (!new_bh) {
 835 getblk_failed:
 836                                 ext4_free_blocks(handle, inode, 0, block, 1,
 837                                                  EXT4_FREE_BLOCKS_METADATA);
 838                                 error = -EIO;
 839                                 goto cleanup;
 840                         }
 841                         lock_buffer(new_bh);
 842                         error = ext4_journal_get_create_access(handle, new_bh);
 843                         if (error) {
 844                                 unlock_buffer(new_bh);
 845                                 goto getblk_failed;
 846                         }
 847                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 848                         set_buffer_uptodate(new_bh);
 849                         unlock_buffer(new_bh);
 850                         ext4_xattr_cache_insert(new_bh);
 851                         error = ext4_handle_dirty_metadata(handle,
 852                                                            inode, new_bh);
 853                         if (error)
 854                                 goto cleanup;
 855                 }
 856         }
 857
 858         /* Update the inode. */
 859         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 860
 861         /* Drop the previous xattr block. */
 862         if (bs->bh && bs->bh != new_bh)
 863                 ext4_xattr_release_block(handle, inode, bs->bh);
 864         error = 0;
 865
 866 cleanup:
 867         if (ce)
 868                 mb_cache_entry_release(ce);
 869         brelse(new_bh);
 870         if (!(bs->bh && s->base == bs->bh->b_data))
 871                 kfree(s->base);
 872
 873         return error;
 874
 875 cleanup_dquot:
 876         dquot_free_block(inode, 1);
 877         goto cleanup;
 878
 879 bad_block:
 880         EXT4_ERROR_INODE(inode, "bad block %llu",
 881                          EXT4_I(inode)->i_file_acl);
 882         goto cleanup;
 883
 884 #undef header
 885 }
 886
 887 struct ext4_xattr_ibody_find {
 888         struct ext4_xattr_search s;
 889         struct ext4_iloc iloc;
 890 };
 891
 892 static int
 893 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 894                       struct ext4_xattr_ibody_find *is)
 895 {
 896         struct ext4_xattr_ibody_header *header;
 897         struct ext4_inode *raw_inode;
 898         int error;
 899
 900         if (EXT4_I(inode)->i_extra_isize == 0)
 901                 return 0;
 902         raw_inode = ext4_raw_inode(&is->iloc);
 903         header = IHDR(inode, raw_inode);
 904         is->s.base = is->s.first = IFIRST(header);
 905         is->s.here = is->s.first;
 906         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 907         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 908                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 909                 if (error)
 910                         return error;
 911                 /* Find the named attribute. */
 912                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 913                                               i->name, is->s.end -
 914                                               (void *)is->s.base, 0);
 915                 if (error && error != -ENODATA)
 916                         return error;
 917                 is->s.not_found = error;
 918         }
 919         return 0;
 920 }
 921
 922 static int
 923 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 924                      struct ext4_xattr_info *i,
 925                      struct ext4_xattr_ibody_find *is)
 926 {
 927         struct ext4_xattr_ibody_header *header;
 928         struct ext4_xattr_search *s = &is->s;
 929         int error;
 930
 931         if (EXT4_I(inode)->i_extra_isize == 0)
 932                 return -ENOSPC;
 933         error = ext4_xattr_set_entry(i, s);
 934         if (error)
 935                 return error;
 936         header = IHDR(inode, ext4_raw_inode(&is->iloc));
 937         if (!IS_LAST_ENTRY(s->first)) {
 938                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 939                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
 940         } else {
 941                 header->h_magic = cpu_to_le32(0);
 942                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
 943         }
 944         return 0;
 945 }
 946
 947 /*
 948  * ext4_xattr_set_handle()
 949  *
 950  * Create, replace or remove an extended attribute for this inode.  Value
 951  * is NULL to remove an existing extended attribute, and non-NULL to
 952  * either replace an existing extended attribute, or create a new extended
 953  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
 954  * specify that an extended attribute must exist and must not exist
 955  * previous to the call, respectively.
 956  *
 957  * Returns 0, or a negative error number on failure.
 958  */
 959 int
 960 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 961                       const char *name, const void *value, size_t value_len,
 962                       int flags)
 963 {
 964         struct ext4_xattr_info i = {
 965                 .name_index = name_index,
 966                 .name = name,
 967                 .value = value,
 968                 .value_len = value_len,
 969
 970         };
 971         struct ext4_xattr_ibody_find is = {
 972                 .s = { .not_found = -ENODATA, },
 973         };
 974         struct ext4_xattr_block_find bs = {
 975                 .s = { .not_found = -ENODATA, },
 976         };
 977         unsigned long no_expand;
 978         int error;
 979
 980         if (!name)
 981                 return -EINVAL;
 982         if (strlen(name) > 255)
 983                 return -ERANGE;
 984         down_write(&EXT4_I(inode)->xattr_sem);
 985         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
 986         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
 987
 988         error = ext4_get_inode_loc(inode, &is.iloc);
 989         if (error)
 990                 goto cleanup;
 991
 992         error = ext4_journal_get_write_access(handle, is.iloc.bh);
 993         if (error)
 994                 goto cleanup;
 995
 996         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
 997                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
 998                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
 999                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1000         }
1001
1002         error = ext4_xattr_ibody_find(inode, &i, &is);
1003         if (error)
1004                 goto cleanup;
1005         if (is.s.not_found)
1006                 error = ext4_xattr_block_find(inode, &i, &bs);
1007         if (error)
1008                 goto cleanup;
1009         if (is.s.not_found && bs.s.not_found) {
1010                 error = -ENODATA;
1011                 if (flags & XATTR_REPLACE)
1012                         goto cleanup;
1013                 error = 0;
1014                 if (!value)
1015                         goto cleanup;
1016         } else {
1017                 error = -EEXIST;
1018                 if (flags & XATTR_CREATE)
1019                         goto cleanup;
1020         }
1021         if (!value) {
1022                 if (!is.s.not_found)
1023                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1024                 else if (!bs.s.not_found)
1025                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1026         } else {
1027                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1028                 if (!error && !bs.s.not_found) {
1029                         i.value = NULL;
1030                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1031                 } else if (error == -ENOSPC) {
1032                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1033                                 error = ext4_xattr_block_find(inode, &i, &bs);
1034                                 if (error)
1035                                         goto cleanup;
1036                         }
1037                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1038                         if (error)
1039                                 goto cleanup;
1040                         if (!is.s.not_found) {
1041                                 i.value = NULL;
1042                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1043                                                              &is);
1044                         }
1045                 }
1046         }
1047         if (!error) {
1048                 ext4_xattr_update_super_block(handle, inode->i_sb);
1049                 inode->i_ctime = ext4_current_time(inode);
1050                 if (!value)
1051                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1052                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1053                 /*
1054                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1055                  * error != 0.
1056                  */
1057                 is.iloc.bh = NULL;
1058                 if (IS_SYNC(inode))
1059                         ext4_handle_sync(handle);
1060         }
1061
1062 cleanup:
1063         brelse(is.iloc.bh);
1064         brelse(bs.bh);
1065         if (no_expand == 0)
1066                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1067         up_write(&EXT4_I(inode)->xattr_sem);
1068         return error;
1069 }
1070
1071 /*
1072  * ext4_xattr_set()
1073  *
1074  * Like ext4_xattr_set_handle, but start from an inode. This extended
1075  * attribute modification is a filesystem transaction by itself.
1076  *
1077  * Returns 0, or a negative error number on failure.
1078  */
1079 int
1080 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1081                const void *value, size_t value_len, int flags)
1082 {
1083         handle_t *handle;
1084         int error, retries = 0;
1085
1086 retry:
1087         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1088         if (IS_ERR(handle)) {
1089                 error = PTR_ERR(handle);
1090         } else {
1091                 int error2;
1092
1093                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1094                                               value, value_len, flags);
1095                 error2 = ext4_journal_stop(handle);
1096                 if (error == -ENOSPC &&
1097                     ext4_should_retry_alloc(inode->i_sb, &retries))
1098                         goto retry;
1099                 if (error == 0)
1100                         error = error2;
1101         }
1102
1103         return error;
1104 }
1105
1106 /*
1107  * Shift the EA entries in the inode to create space for the increased
1108  * i_extra_isize.
1109  */
1110 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1111                                      int value_offs_shift, void *to,
1112                                      void *from, size_t n, int blocksize)
1113 {
1114         struct ext4_xattr_entry *last = entry;
1115         int new_offs;
1116
1117         /* Adjust the value offsets of the entries */
1118         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1119                 if (!last->e_value_block && last->e_value_size) {
1120                         new_offs = le16_to_cpu(last->e_value_offs) +
1121                                                         value_offs_shift;
1122                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1123                                  > blocksize);
1124                         last->e_value_offs = cpu_to_le16(new_offs);
1125                 }
1126         }
1127         /* Shift the entries by n bytes */
1128         memmove(to, from, n);
1129 }
1130
1131 /*
1132  * Expand an inode by new_extra_isize bytes when EAs are present.
1133  * Returns 0 on success or negative error number on failure.
1134  */
1135 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1136                                struct ext4_inode *raw_inode, handle_t *handle)
1137 {
1138         struct ext4_xattr_ibody_header *header;
1139         struct ext4_xattr_entry *entry, *last, *first;
1140         struct buffer_head *bh = NULL;
1141         struct ext4_xattr_ibody_find *is = NULL;
1142         struct ext4_xattr_block_find *bs = NULL;
1143         char *buffer = NULL, *b_entry_name = NULL;
1144         size_t min_offs, free;
1145         int total_ino, total_blk;
1146         void *base, *start, *end;
1147         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1148         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1149
1150         down_write(&EXT4_I(inode)->xattr_sem);
1151 retry:
1152         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1153                 up_write(&EXT4_I(inode)->xattr_sem);
1154                 return 0;
1155         }
1156
1157         header = IHDR(inode, raw_inode);
1158         entry = IFIRST(header);
1159
1160         /*
1161          * Check if enough free space is available in the inode to shift the
1162          * entries ahead by new_extra_isize.
1163          */
1164
1165         base = start = entry;
1166         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1167         min_offs = end - base;
1168         last = entry;
1169         total_ino = sizeof(struct ext4_xattr_ibody_header);
1170
1171         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1172         if (free >= new_extra_isize) {
1173                 entry = IFIRST(header);
1174                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1175                                 - new_extra_isize, (void *)raw_inode +
1176                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1177                                 (void *)header, total_ino,
1178                                 inode->i_sb->s_blocksize);
1179                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1180                 error = 0;
1181                 goto cleanup;
1182         }
1183
1184         /*
1185          * Enough free space isn't available in the inode, check if
1186          * EA block can hold new_extra_isize bytes.
1187          */
1188         if (EXT4_I(inode)->i_file_acl) {
1189                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1190                 error = -EIO;
1191                 if (!bh)
1192                         goto cleanup;
1193                 if (ext4_xattr_check_block(bh)) {
1194                         EXT4_ERROR_INODE(inode, "bad block %llu",
1195                                          EXT4_I(inode)->i_file_acl);
1196                         error = -EIO;
1197                         goto cleanup;
1198                 }
1199                 base = BHDR(bh);
1200                 first = BFIRST(bh);
1201                 end = bh->b_data + bh->b_size;
1202                 min_offs = end - base;
1203                 free = ext4_xattr_free_space(first, &min_offs, base,
1204                                              &total_blk);
1205                 if (free < new_extra_isize) {
1206                         if (!tried_min_extra_isize && s_min_extra_isize) {
1207                                 tried_min_extra_isize++;
1208                                 new_extra_isize = s_min_extra_isize;
1209                                 brelse(bh);
1210                                 goto retry;
1211                         }
1212                         error = -1;
1213                         goto cleanup;
1214                 }
1215         } else {
1216                 free = inode->i_sb->s_blocksize;
1217         }
1218
1219         while (new_extra_isize > 0) {
1220                 size_t offs, size, entry_size;
1221                 struct ext4_xattr_entry *small_entry = NULL;
1222                 struct ext4_xattr_info i = {
1223                         .value = NULL,
1224                         .value_len = 0,
1225                 };
1226                 unsigned int total_size;  /* EA entry size + value size */
1227                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1228                 unsigned int min_total_size = ~0U;
1229
1230                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1231                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1232                 if (!is || !bs) {
1233                         error = -ENOMEM;
1234                         goto cleanup;
1235                 }
1236
1237                 is->s.not_found = -ENODATA;
1238                 bs->s.not_found = -ENODATA;
1239                 is->iloc.bh = NULL;
1240                 bs->bh = NULL;
1241
1242                 last = IFIRST(header);
1243                 /* Find the entry best suited to be pushed into EA block */
1244                 entry = NULL;
1245                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1246                         total_size =
1247                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1248                                         EXT4_XATTR_LEN(last->e_name_len);
1249                         if (total_size <= free && total_size < min_total_size) {
1250                                 if (total_size < new_extra_isize) {
1251                                         small_entry = last;
1252                                 } else {
1253                                         entry = last;
1254                                         min_total_size = total_size;
1255                                 }
1256                         }
1257                 }
1258
1259                 if (entry == NULL) {
1260                         if (small_entry) {
1261                                 entry = small_entry;
1262                         } else {
1263                                 if (!tried_min_extra_isize &&
1264                                     s_min_extra_isize) {
1265                                         tried_min_extra_isize++;
1266                                         new_extra_isize = s_min_extra_isize;
1267                                         goto retry;
1268                                 }
1269                                 error = -1;
1270                                 goto cleanup;
1271                         }
1272                 }
1273                 offs = le16_to_cpu(entry->e_value_offs);
1274                 size = le32_to_cpu(entry->e_value_size);
1275                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1276                 i.name_index = entry->e_name_index,
1277                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1278                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1279                 if (!buffer || !b_entry_name) {
1280                         error = -ENOMEM;
1281                         goto cleanup;
1282                 }
1283                 /* Save the entry name and the entry value */
1284                 memcpy(buffer, (void *)IFIRST(header) + offs,
1285                        EXT4_XATTR_SIZE(size));
1286                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1287                 b_entry_name[entry->e_name_len] = '\0';
1288                 i.name = b_entry_name;
1289
1290                 error = ext4_get_inode_loc(inode, &is->iloc);
1291                 if (error)
1292                         goto cleanup;
1293
1294                 error = ext4_xattr_ibody_find(inode, &i, is);
1295                 if (error)
1296                         goto cleanup;
1297
1298                 /* Remove the chosen entry from the inode */
1299                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1300                 if (error)
1301                         goto cleanup;
1302
1303                 entry = IFIRST(header);
1304                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1305                         shift_bytes = new_extra_isize;
1306                 else
1307                         shift_bytes = entry_size + size;
1308                 /* Adjust the offsets and shift the remaining entries ahead */
1309                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1310                         shift_bytes, (void *)raw_inode +
1311                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1312                         (void *)header, total_ino - entry_size,
1313                         inode->i_sb->s_blocksize);
1314
1315                 extra_isize += shift_bytes;
1316                 new_extra_isize -= shift_bytes;
1317                 EXT4_I(inode)->i_extra_isize = extra_isize;
1318
1319                 i.name = b_entry_name;
1320                 i.value = buffer;
1321                 i.value_len = size;
1322                 error = ext4_xattr_block_find(inode, &i, bs);
1323                 if (error)
1324                         goto cleanup;
1325
1326                 /* Add entry which was removed from the inode into the block */
1327                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1328                 if (error)
1329                         goto cleanup;
1330                 kfree(b_entry_name);
1331                 kfree(buffer);
1332                 b_entry_name = NULL;
1333                 buffer = NULL;
1334                 brelse(is->iloc.bh);
1335                 kfree(is);
1336                 kfree(bs);
1337         }
1338         brelse(bh);
1339         up_write(&EXT4_I(inode)->xattr_sem);
1340         return 0;
1341
1342 cleanup:
1343         kfree(b_entry_name);
1344         kfree(buffer);
1345         if (is)
1346                 brelse(is->iloc.bh);
1347         kfree(is);
1348         kfree(bs);
1349         brelse(bh);
1350         up_write(&EXT4_I(inode)->xattr_sem);
1351         return error;
1352 }
1353
1354
1355
1356 /*
1357  * ext4_xattr_delete_inode()
1358  *
1359  * Free extended attribute resources associated with this inode. This
1360  * is called immediately before an inode is freed. We have exclusive
1361  * access to the inode.
1362  */
1363 void
1364 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1365 {
1366         struct buffer_head *bh = NULL;
1367
1368         if (!EXT4_I(inode)->i_file_acl)
1369                 goto cleanup;
1370         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1371         if (!bh) {
1372                 EXT4_ERROR_INODE(inode, "block %llu read error",
1373                                  EXT4_I(inode)->i_file_acl);
1374                 goto cleanup;
1375         }
1376         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1377             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1378                 EXT4_ERROR_INODE(inode, "bad block %llu",
1379                                  EXT4_I(inode)->i_file_acl);
1380                 goto cleanup;
1381         }
1382         ext4_xattr_release_block(handle, inode, bh);
1383         EXT4_I(inode)->i_file_acl = 0;
1384
1385 cleanup:
1386         brelse(bh);
1387 }
1388
1389 /*
1390  * ext4_xattr_put_super()
1391  *
1392  * This is called when a file system is unmounted.
1393  */
1394 void
1395 ext4_xattr_put_super(struct super_block *sb)
1396 {
1397         mb_cache_shrink(sb->s_bdev);
1398 }
1399
1400 /*
1401  * ext4_xattr_cache_insert()
1402  *
1403  * Create a new entry in the extended attribute cache, and insert
1404  * it unless such an entry is already in the cache.
1405  *
1406  * Returns 0, or a negative error number on failure.
1407  */
1408 static void
1409 ext4_xattr_cache_insert(struct buffer_head *bh)
1410 {
1411         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1412         struct mb_cache_entry *ce;
1413         int error;
1414
1415         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1416         if (!ce) {
1417                 ea_bdebug(bh, "out of memory");
1418                 return;
1419         }
1420         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1421         if (error) {
1422                 mb_cache_entry_free(ce);
1423                 if (error == -EBUSY) {
1424                         ea_bdebug(bh, "already in cache");
1425                         error = 0;
1426                 }
1427         } else {
1428                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1429                 mb_cache_entry_release(ce);
1430         }
1431 }
1432
1433 /*
1434  * ext4_xattr_cmp()
1435  *
1436  * Compare two extended attribute blocks for equality.
1437  *
1438  * Returns 0 if the blocks are equal, 1 if they differ, and
1439  * a negative error number on errors.
1440  */
1441 static int
1442 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1443                struct ext4_xattr_header *header2)
1444 {
1445         struct ext4_xattr_entry *entry1, *entry2;
1446
1447         entry1 = ENTRY(header1+1);
1448         entry2 = ENTRY(header2+1);
1449         while (!IS_LAST_ENTRY(entry1)) {
1450                 if (IS_LAST_ENTRY(entry2))
1451                         return 1;
1452                 if (entry1->e_hash != entry2->e_hash ||
1453                     entry1->e_name_index != entry2->e_name_index ||
1454                     entry1->e_name_len != entry2->e_name_len ||
1455                     entry1->e_value_size != entry2->e_value_size ||
1456                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1457                         return 1;
1458                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1459                         return -EIO;
1460                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1461                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1462                            le32_to_cpu(entry1->e_value_size)))
1463                         return 1;
1464
1465                 entry1 = EXT4_XATTR_NEXT(entry1);
1466                 entry2 = EXT4_XATTR_NEXT(entry2);
1467         }
1468         if (!IS_LAST_ENTRY(entry2))
1469                 return 1;
1470         return 0;
1471 }
1472
1473 /*
1474  * ext4_xattr_cache_find()
1475  *
1476  * Find an identical extended attribute block.
1477  *
1478  * Returns a pointer to the block found, or NULL if such a block was
1479  * not found or an error occurred.
1480  */
1481 static struct buffer_head *
1482 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1483                       struct mb_cache_entry **pce)
1484 {
1485         __u32 hash = le32_to_cpu(header->h_hash);
1486         struct mb_cache_entry *ce;
1487
1488         if (!header->h_hash)
1489                 return NULL;  /* never share */
1490         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1491 again:
1492         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1493                                        hash);
1494         while (ce) {
1495                 struct buffer_head *bh;
1496
1497                 if (IS_ERR(ce)) {
1498                         if (PTR_ERR(ce) == -EAGAIN)
1499                                 goto again;
1500                         break;
1501                 }
1502                 bh = sb_bread(inode->i_sb, ce->e_block);
1503                 if (!bh) {
1504                         EXT4_ERROR_INODE(inode, "block %lu read error",
1505                                          (unsigned long) ce->e_block);
1506                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1507                                 EXT4_XATTR_REFCOUNT_MAX) {
1508                         ea_idebug(inode, "block %lu refcount %d>=%d",
1509                                   (unsigned long) ce->e_block,
1510                                   le32_to_cpu(BHDR(bh)->h_refcount),
1511                                           EXT4_XATTR_REFCOUNT_MAX);
1512                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1513                         *pce = ce;
1514                         return bh;
1515                 }
1516                 brelse(bh);
1517                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1518         }
1519         return NULL;
1520 }
1521
1522 #define NAME_HASH_SHIFT 5
1523 #define VALUE_HASH_SHIFT 16
1524
1525 /*
1526  * ext4_xattr_hash_entry()
1527  *
1528  * Compute the hash of an extended attribute.
1529  */
1530 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1531                                          struct ext4_xattr_entry *entry)
1532 {
1533         __u32 hash = 0;
1534         char *name = entry->e_name;
1535         int n;
1536
1537         for (n = 0; n < entry->e_name_len; n++) {
1538                 hash = (hash << NAME_HASH_SHIFT) ^
1539                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1540                        *name++;
1541         }
1542
1543         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1544                 __le32 *value = (__le32 *)((char *)header +
1545                         le16_to_cpu(entry->e_value_offs));
1546                 for (n = (le32_to_cpu(entry->e_value_size) +
1547                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1548                         hash = (hash << VALUE_HASH_SHIFT) ^
1549                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1550                                le32_to_cpu(*value++);
1551                 }
1552         }
1553         entry->e_hash = cpu_to_le32(hash);
1554 }
1555
1556 #undef NAME_HASH_SHIFT
1557 #undef VALUE_HASH_SHIFT
1558
1559 #define BLOCK_HASH_SHIFT 16
1560
1561 /*
1562  * ext4_xattr_rehash()
1563  *
1564  * Re-compute the extended attribute hash value after an entry has changed.
1565  */
1566 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1567                               struct ext4_xattr_entry *entry)
1568 {
1569         struct ext4_xattr_entry *here;
1570         __u32 hash = 0;
1571
1572         ext4_xattr_hash_entry(header, entry);
1573         here = ENTRY(header+1);
1574         while (!IS_LAST_ENTRY(here)) {
1575                 if (!here->e_hash) {
1576                         /* Block is not shared if an entry's hash value == 0 */
1577                         hash = 0;
1578                         break;
1579                 }
1580                 hash = (hash << BLOCK_HASH_SHIFT) ^
1581                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1582                        le32_to_cpu(here->e_hash);
1583                 here = EXT4_XATTR_NEXT(here);
1584         }
1585         header->h_hash = cpu_to_le32(hash);
1586 }
1587
1588 #undef BLOCK_HASH_SHIFT
1589
1590 int __init
1591 ext4_init_xattr(void)
1592 {
1593         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1594         if (!ext4_xattr_cache)
1595                 return -ENOMEM;
1596         return 0;
1597 }
1598
1599 void
1600 ext4_exit_xattr(void)
1601 {
1602         if (ext4_xattr_cache)
1603                 mb_cache_destroy(ext4_xattr_cache);
1604         ext4_xattr_cache = NULL;
1605 }