fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   5  *
   6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   7  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  13  *  and Andreas Gruenbacher <agruen@suse.de>.
  14  */
  15
  16 /*
  17  * Extended attributes are stored directly in inodes (on file systems with
  18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19  * field contains the block number if an inode uses an additional block. All
  20  * attributes must fit in the inode and one additional block. Blocks that
  21  * contain the identical set of attributes may be shared among several inodes.
  22  * Identical blocks are detected by keeping a cache of blocks that have
  23  * recently been accessed.
  24  *
  25  * The attributes in inodes and on blocks have a different header; the entries
  26  * are stored in the same format:
  27  *
  28  *   +------------------+
  29  *   | header           |
  30  *   | entry 1          | |
  31  *   | entry 2          | | growing downwards
  32  *   | entry 3          | v
  33  *   | four null bytes  |
  34  *   | . . .            |
  35  *   | value 1          | ^
  36  *   | value 3          | | growing upwards
  37  *   | value 2          | |
  38  *   +------------------+
  39  *
  40  * The header is followed by multiple entry descriptors. In disk blocks, the
  41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42  * attribute values are aligned to the end of the block in no specific order.
  43  *
  44  * Locking strategy
  45  * ----------------
  46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47  * EA blocks are only changed if they are exclusive to an inode, so
  48  * holding xattr_sem also means that nothing but the EA block's reference
  49  * count can change. Multiple writers to the same block are synchronized
  50  * by the buffer lock.
  51  */
  52
  53 #include <linux/init.h>
  54 #include <linux/fs.h>
  55 #include <linux/slab.h>
  56 #include <linux/mbcache.h>
  57 #include <linux/quotaops.h>
  58 #include <linux/rwsem.h>
  59 #include "ext4_jbd2.h"
  60 #include "ext4.h"
  61 #include "xattr.h"
  62 #include "acl.h"
  63
  64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
  65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
  66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
  67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
  68
  69 #ifdef EXT4_XATTR_DEBUG
  70 # define ea_idebug(inode, f...) do { \
  71                 printk(KERN_DEBUG "inode %s:%lu: ", \
  72                         inode->i_sb->s_id, inode->i_ino); \
  73                 printk(f); \
  74                 printk("\n"); \
  75         } while (0)
  76 # define ea_bdebug(bh, f...) do { \
  77                 char b[BDEVNAME_SIZE]; \
  78                 printk(KERN_DEBUG "block %s:%lu: ", \
  79                         bdevname(bh->b_bdev, b), \
  80                         (unsigned long) bh->b_blocknr); \
  81                 printk(f); \
  82                 printk("\n"); \
  83         } while (0)
  84 #else
  85 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  86 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  87 #endif
  88
  89 static void ext4_xattr_cache_insert(struct buffer_head *);
  90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
  91                                                  struct ext4_xattr_header *,
  92                                                  struct mb_cache_entry **);
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
  94                               struct ext4_xattr_entry *);
  95 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
  96                            size_t buffer_size);
  97
  98 static struct mb_cache *ext4_xattr_cache;
  99
 100 static const struct xattr_handler *ext4_xattr_handler_map[] = {
 101         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 103         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
 104         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
 105 #endif
 106         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
 107 #ifdef CONFIG_EXT4_FS_SECURITY
 108         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
 109 #endif
 110 };
 111
 112 const struct xattr_handler *ext4_xattr_handlers[] = {
 113         &ext4_xattr_user_handler,
 114         &ext4_xattr_trusted_handler,
 115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 116         &ext4_xattr_acl_access_handler,
 117         &ext4_xattr_acl_default_handler,
 118 #endif
 119 #ifdef CONFIG_EXT4_FS_SECURITY
 120         &ext4_xattr_security_handler,
 121 #endif
 122         NULL
 123 };
 124
 125 static 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         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 162             BHDR(bh)->h_blocks != cpu_to_le32(1))
 163                 return -EIO;
 164         return ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
 165 }
 166
 167 static inline int
 168 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
 169 {
 170         size_t value_size = le32_to_cpu(entry->e_value_size);
 171
 172         if (entry->e_value_block != 0 || value_size > size ||
 173             le16_to_cpu(entry->e_value_offs) + value_size > size)
 174                 return -EIO;
 175         return 0;
 176 }
 177
 178 static int
 179 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 180                       const char *name, size_t size, int sorted)
 181 {
 182         struct ext4_xattr_entry *entry;
 183         size_t name_len;
 184         int cmp = 1;
 185
 186         if (name == NULL)
 187                 return -EINVAL;
 188         name_len = strlen(name);
 189         entry = *pentry;
 190         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 191                 cmp = name_index - entry->e_name_index;
 192                 if (!cmp)
 193                         cmp = name_len - entry->e_name_len;
 194                 if (!cmp)
 195                         cmp = memcmp(name, entry->e_name, name_len);
 196                 if (cmp <= 0 && (sorted || cmp == 0))
 197                         break;
 198         }
 199         *pentry = entry;
 200         if (!cmp && ext4_xattr_check_entry(entry, size))
 201                         return -EIO;
 202         return cmp ? -ENODATA : 0;
 203 }
 204
 205 static int
 206 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 207                      void *buffer, size_t buffer_size)
 208 {
 209         struct buffer_head *bh = NULL;
 210         struct ext4_xattr_entry *entry;
 211         size_t size;
 212         int error;
 213
 214         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 215                   name_index, name, buffer, (long)buffer_size);
 216
 217         error = -ENODATA;
 218         if (!EXT4_I(inode)->i_file_acl)
 219                 goto cleanup;
 220         ea_idebug(inode, "reading block %llu",
 221                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 222         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 223         if (!bh)
 224                 goto cleanup;
 225         ea_bdebug(bh, "b_count=%d, refcount=%d",
 226                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 227         if (ext4_xattr_check_block(bh)) {
 228 bad_block:
 229                 EXT4_ERROR_INODE(inode, "bad block %llu",
 230                                  EXT4_I(inode)->i_file_acl);
 231                 error = -EIO;
 232                 goto cleanup;
 233         }
 234         ext4_xattr_cache_insert(bh);
 235         entry = BFIRST(bh);
 236         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
 237         if (error == -EIO)
 238                 goto bad_block;
 239         if (error)
 240                 goto cleanup;
 241         size = le32_to_cpu(entry->e_value_size);
 242         if (buffer) {
 243                 error = -ERANGE;
 244                 if (size > buffer_size)
 245                         goto cleanup;
 246                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
 247                        size);
 248         }
 249         error = size;
 250
 251 cleanup:
 252         brelse(bh);
 253         return error;
 254 }
 255
 256 static int
 257 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 258                      void *buffer, size_t buffer_size)
 259 {
 260         struct ext4_xattr_ibody_header *header;
 261         struct ext4_xattr_entry *entry;
 262         struct ext4_inode *raw_inode;
 263         struct ext4_iloc iloc;
 264         size_t size;
 265         void *end;
 266         int error;
 267
 268         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 269                 return -ENODATA;
 270         error = ext4_get_inode_loc(inode, &iloc);
 271         if (error)
 272                 return error;
 273         raw_inode = ext4_raw_inode(&iloc);
 274         header = IHDR(inode, raw_inode);
 275         entry = IFIRST(header);
 276         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 277         error = ext4_xattr_check_names(entry, end);
 278         if (error)
 279                 goto cleanup;
 280         error = ext4_xattr_find_entry(&entry, name_index, name,
 281                                       end - (void *)entry, 0);
 282         if (error)
 283                 goto cleanup;
 284         size = le32_to_cpu(entry->e_value_size);
 285         if (buffer) {
 286                 error = -ERANGE;
 287                 if (size > buffer_size)
 288                         goto cleanup;
 289                 memcpy(buffer, (void *)IFIRST(header) +
 290                        le16_to_cpu(entry->e_value_offs), size);
 291         }
 292         error = size;
 293
 294 cleanup:
 295         brelse(iloc.bh);
 296         return error;
 297 }
 298
 299 /*
 300  * ext4_xattr_get()
 301  *
 302  * Copy an extended attribute into the buffer
 303  * provided, or compute the buffer size required.
 304  * Buffer is NULL to compute the size of the buffer required.
 305  *
 306  * Returns a negative error number on failure, or the number of bytes
 307  * used / required on success.
 308  */
 309 int
 310 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 311                void *buffer, size_t buffer_size)
 312 {
 313         int error;
 314
 315         down_read(&EXT4_I(inode)->xattr_sem);
 316         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 317                                      buffer_size);
 318         if (error == -ENODATA)
 319                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 320                                              buffer_size);
 321         up_read(&EXT4_I(inode)->xattr_sem);
 322         return error;
 323 }
 324
 325 static int
 326 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 327                         char *buffer, size_t buffer_size)
 328 {
 329         size_t rest = buffer_size;
 330
 331         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 332                 const struct xattr_handler *handler =
 333                         ext4_xattr_handler(entry->e_name_index);
 334
 335                 if (handler) {
 336                         size_t size = handler->list(dentry, buffer, rest,
 337                                                     entry->e_name,
 338                                                     entry->e_name_len,
 339                                                     handler->flags);
 340                         if (buffer) {
 341                                 if (size > rest)
 342                                         return -ERANGE;
 343                                 buffer += size;
 344                         }
 345                         rest -= size;
 346                 }
 347         }
 348         return buffer_size - rest;
 349 }
 350
 351 static int
 352 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 353 {
 354         struct inode *inode = dentry->d_inode;
 355         struct buffer_head *bh = NULL;
 356         int error;
 357
 358         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 359                   buffer, (long)buffer_size);
 360
 361         error = 0;
 362         if (!EXT4_I(inode)->i_file_acl)
 363                 goto cleanup;
 364         ea_idebug(inode, "reading block %llu",
 365                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 366         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 367         error = -EIO;
 368         if (!bh)
 369                 goto cleanup;
 370         ea_bdebug(bh, "b_count=%d, refcount=%d",
 371                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 372         if (ext4_xattr_check_block(bh)) {
 373                 EXT4_ERROR_INODE(inode, "bad block %llu",
 374                                  EXT4_I(inode)->i_file_acl);
 375                 error = -EIO;
 376                 goto cleanup;
 377         }
 378         ext4_xattr_cache_insert(bh);
 379         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 380
 381 cleanup:
 382         brelse(bh);
 383
 384         return error;
 385 }
 386
 387 static int
 388 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 389 {
 390         struct inode *inode = dentry->d_inode;
 391         struct ext4_xattr_ibody_header *header;
 392         struct ext4_inode *raw_inode;
 393         struct ext4_iloc iloc;
 394         void *end;
 395         int error;
 396
 397         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 398                 return 0;
 399         error = ext4_get_inode_loc(inode, &iloc);
 400         if (error)
 401                 return error;
 402         raw_inode = ext4_raw_inode(&iloc);
 403         header = IHDR(inode, raw_inode);
 404         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 405         error = ext4_xattr_check_names(IFIRST(header), end);
 406         if (error)
 407                 goto cleanup;
 408         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 409                                         buffer, buffer_size);
 410
 411 cleanup:
 412         brelse(iloc.bh);
 413         return error;
 414 }
 415
 416 /*
 417  * ext4_xattr_list()
 418  *
 419  * Copy a list of attribute names into the buffer
 420  * provided, or compute the buffer size required.
 421  * Buffer is NULL to compute the size of the buffer required.
 422  *
 423  * Returns a negative error number on failure, or the number of bytes
 424  * used / required on success.
 425  */
 426 static int
 427 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 428 {
 429         int ret, ret2;
 430
 431         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 432         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 433         if (ret < 0)
 434                 goto errout;
 435         if (buffer) {
 436                 buffer += ret;
 437                 buffer_size -= ret;
 438         }
 439         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 440         if (ret < 0)
 441                 goto errout;
 442         ret += ret2;
 443 errout:
 444         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
 445         return ret;
 446 }
 447
 448 /*
 449  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 450  * not set, set it.
 451  */
 452 static void ext4_xattr_update_super_block(handle_t *handle,
 453                                           struct super_block *sb)
 454 {
 455         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
 456                 return;
 457
 458         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 459                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
 460                 ext4_handle_dirty_super(handle, sb);
 461         }
 462 }
 463
 464 /*
 465  * Release the xattr block BH: If the reference count is > 1, decrement
 466  * it; otherwise free the block.
 467  */
 468 static void
 469 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 470                          struct buffer_head *bh)
 471 {
 472         struct mb_cache_entry *ce = NULL;
 473         int error = 0;
 474
 475         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
 476         error = ext4_journal_get_write_access(handle, bh);
 477         if (error)
 478                 goto out;
 479
 480         lock_buffer(bh);
 481         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
 482                 ea_bdebug(bh, "refcount now=0; freeing");
 483                 if (ce)
 484                         mb_cache_entry_free(ce);
 485                 get_bh(bh);
 486                 ext4_free_blocks(handle, inode, bh, 0, 1,
 487                                  EXT4_FREE_BLOCKS_METADATA |
 488                                  EXT4_FREE_BLOCKS_FORGET);
 489                 unlock_buffer(bh);
 490         } else {
 491                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
 492                 if (ce)
 493                         mb_cache_entry_release(ce);
 494                 unlock_buffer(bh);
 495                 error = ext4_handle_dirty_metadata(handle, inode, bh);
 496                 if (IS_SYNC(inode))
 497                         ext4_handle_sync(handle);
 498                 dquot_free_block(inode, 1);
 499                 ea_bdebug(bh, "refcount now=%d; releasing",
 500                           le32_to_cpu(BHDR(bh)->h_refcount));
 501         }
 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                         ext4_handle_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                         /*
 824                          * take i_data_sem because we will test
 825                          * i_delalloc_reserved_flag in ext4_mb_new_blocks
 826                          */
 827                         down_read((&EXT4_I(inode)->i_data_sem));
 828                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
 829                                                      NULL, &error);
 830                         up_read((&EXT4_I(inode)->i_data_sem));
 831                         if (error)
 832                                 goto cleanup;
 833
 834                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 835                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
 836
 837                         ea_idebug(inode, "creating block %llu",
 838                                   (unsigned long long)block);
 839
 840                         new_bh = sb_getblk(sb, block);
 841                         if (!new_bh) {
 842 getblk_failed:
 843                                 ext4_free_blocks(handle, inode, NULL, block, 1,
 844                                                  EXT4_FREE_BLOCKS_METADATA);
 845                                 error = -EIO;
 846                                 goto cleanup;
 847                         }
 848                         lock_buffer(new_bh);
 849                         error = ext4_journal_get_create_access(handle, new_bh);
 850                         if (error) {
 851                                 unlock_buffer(new_bh);
 852                                 goto getblk_failed;
 853                         }
 854                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
 855                         set_buffer_uptodate(new_bh);
 856                         unlock_buffer(new_bh);
 857                         ext4_xattr_cache_insert(new_bh);
 858                         error = ext4_handle_dirty_metadata(handle,
 859                                                            inode, new_bh);
 860                         if (error)
 861                                 goto cleanup;
 862                 }
 863         }
 864
 865         /* Update the inode. */
 866         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 867
 868         /* Drop the previous xattr block. */
 869         if (bs->bh && bs->bh != new_bh)
 870                 ext4_xattr_release_block(handle, inode, bs->bh);
 871         error = 0;
 872
 873 cleanup:
 874         if (ce)
 875                 mb_cache_entry_release(ce);
 876         brelse(new_bh);
 877         if (!(bs->bh && s->base == bs->bh->b_data))
 878                 kfree(s->base);
 879
 880         return error;
 881
 882 cleanup_dquot:
 883         dquot_free_block(inode, 1);
 884         goto cleanup;
 885
 886 bad_block:
 887         EXT4_ERROR_INODE(inode, "bad block %llu",
 888                          EXT4_I(inode)->i_file_acl);
 889         goto cleanup;
 890
 891 #undef header
 892 }
 893
 894 struct ext4_xattr_ibody_find {
 895         struct ext4_xattr_search s;
 896         struct ext4_iloc iloc;
 897 };
 898
 899 static int
 900 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 901                       struct ext4_xattr_ibody_find *is)
 902 {
 903         struct ext4_xattr_ibody_header *header;
 904         struct ext4_inode *raw_inode;
 905         int error;
 906
 907         if (EXT4_I(inode)->i_extra_isize == 0)
 908                 return 0;
 909         raw_inode = ext4_raw_inode(&is->iloc);
 910         header = IHDR(inode, raw_inode);
 911         is->s.base = is->s.first = IFIRST(header);
 912         is->s.here = is->s.first;
 913         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 914         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 915                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 916                 if (error)
 917                         return error;
 918                 /* Find the named attribute. */
 919                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
 920                                               i->name, is->s.end -
 921                                               (void *)is->s.base, 0);
 922                 if (error && error != -ENODATA)
 923                         return error;
 924                 is->s.not_found = error;
 925         }
 926         return 0;
 927 }
 928
 929 static int
 930 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 931                      struct ext4_xattr_info *i,
 932                      struct ext4_xattr_ibody_find *is)
 933 {
 934         struct ext4_xattr_ibody_header *header;
 935         struct ext4_xattr_search *s = &is->s;
 936         int error;
 937
 938         if (EXT4_I(inode)->i_extra_isize == 0)
 939                 return -ENOSPC;
 940         error = ext4_xattr_set_entry(i, s);
 941         if (error)
 942                 return error;
 943         header = IHDR(inode, ext4_raw_inode(&is->iloc));
 944         if (!IS_LAST_ENTRY(s->first)) {
 945                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 946                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
 947         } else {
 948                 header->h_magic = cpu_to_le32(0);
 949                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
 950         }
 951         return 0;
 952 }
 953
 954 /*
 955  * ext4_xattr_set_handle()
 956  *
 957  * Create, replace or remove an extended attribute for this inode.  Value
 958  * is NULL to remove an existing extended attribute, and non-NULL to
 959  * either replace an existing extended attribute, or create a new extended
 960  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
 961  * specify that an extended attribute must exist and must not exist
 962  * previous to the call, respectively.
 963  *
 964  * Returns 0, or a negative error number on failure.
 965  */
 966 int
 967 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 968                       const char *name, const void *value, size_t value_len,
 969                       int flags)
 970 {
 971         struct ext4_xattr_info i = {
 972                 .name_index = name_index,
 973                 .name = name,
 974                 .value = value,
 975                 .value_len = value_len,
 976
 977         };
 978         struct ext4_xattr_ibody_find is = {
 979                 .s = { .not_found = -ENODATA, },
 980         };
 981         struct ext4_xattr_block_find bs = {
 982                 .s = { .not_found = -ENODATA, },
 983         };
 984         unsigned long no_expand;
 985         int error;
 986
 987         if (!name)
 988                 return -EINVAL;
 989         if (strlen(name) > 255)
 990                 return -ERANGE;
 991         down_write(&EXT4_I(inode)->xattr_sem);
 992         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
 993         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
 994
 995         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
 996         if (error)
 997                 goto cleanup;
 998
 999         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1000                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1001                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1002                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1003         }
1004
1005         error = ext4_xattr_ibody_find(inode, &i, &is);
1006         if (error)
1007                 goto cleanup;
1008         if (is.s.not_found)
1009                 error = ext4_xattr_block_find(inode, &i, &bs);
1010         if (error)
1011                 goto cleanup;
1012         if (is.s.not_found && bs.s.not_found) {
1013                 error = -ENODATA;
1014                 if (flags & XATTR_REPLACE)
1015                         goto cleanup;
1016                 error = 0;
1017                 if (!value)
1018                         goto cleanup;
1019         } else {
1020                 error = -EEXIST;
1021                 if (flags & XATTR_CREATE)
1022                         goto cleanup;
1023         }
1024         if (!value) {
1025                 if (!is.s.not_found)
1026                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1027                 else if (!bs.s.not_found)
1028                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1029         } else {
1030                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1031                 if (!error && !bs.s.not_found) {
1032                         i.value = NULL;
1033                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1034                 } else if (error == -ENOSPC) {
1035                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1036                                 error = ext4_xattr_block_find(inode, &i, &bs);
1037                                 if (error)
1038                                         goto cleanup;
1039                         }
1040                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1041                         if (error)
1042                                 goto cleanup;
1043                         if (!is.s.not_found) {
1044                                 i.value = NULL;
1045                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1046                                                              &is);
1047                         }
1048                 }
1049         }
1050         if (!error) {
1051                 ext4_xattr_update_super_block(handle, inode->i_sb);
1052                 inode->i_ctime = ext4_current_time(inode);
1053                 if (!value)
1054                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1055                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1056                 /*
1057                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1058                  * error != 0.
1059                  */
1060                 is.iloc.bh = NULL;
1061                 if (IS_SYNC(inode))
1062                         ext4_handle_sync(handle);
1063         }
1064
1065 cleanup:
1066         brelse(is.iloc.bh);
1067         brelse(bs.bh);
1068         if (no_expand == 0)
1069                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1070         up_write(&EXT4_I(inode)->xattr_sem);
1071         return error;
1072 }
1073
1074 /*
1075  * ext4_xattr_set()
1076  *
1077  * Like ext4_xattr_set_handle, but start from an inode. This extended
1078  * attribute modification is a filesystem transaction by itself.
1079  *
1080  * Returns 0, or a negative error number on failure.
1081  */
1082 int
1083 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1084                const void *value, size_t value_len, int flags)
1085 {
1086         handle_t *handle;
1087         int error, retries = 0;
1088
1089 retry:
1090         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1091         if (IS_ERR(handle)) {
1092                 error = PTR_ERR(handle);
1093         } else {
1094                 int error2;
1095
1096                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1097                                               value, value_len, flags);
1098                 error2 = ext4_journal_stop(handle);
1099                 if (error == -ENOSPC &&
1100                     ext4_should_retry_alloc(inode->i_sb, &retries))
1101                         goto retry;
1102                 if (error == 0)
1103                         error = error2;
1104         }
1105
1106         return error;
1107 }
1108
1109 /*
1110  * Shift the EA entries in the inode to create space for the increased
1111  * i_extra_isize.
1112  */
1113 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1114                                      int value_offs_shift, void *to,
1115                                      void *from, size_t n, int blocksize)
1116 {
1117         struct ext4_xattr_entry *last = entry;
1118         int new_offs;
1119
1120         /* Adjust the value offsets of the entries */
1121         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1122                 if (!last->e_value_block && last->e_value_size) {
1123                         new_offs = le16_to_cpu(last->e_value_offs) +
1124                                                         value_offs_shift;
1125                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1126                                  > blocksize);
1127                         last->e_value_offs = cpu_to_le16(new_offs);
1128                 }
1129         }
1130         /* Shift the entries by n bytes */
1131         memmove(to, from, n);
1132 }
1133
1134 /*
1135  * Expand an inode by new_extra_isize bytes when EAs are present.
1136  * Returns 0 on success or negative error number on failure.
1137  */
1138 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1139                                struct ext4_inode *raw_inode, handle_t *handle)
1140 {
1141         struct ext4_xattr_ibody_header *header;
1142         struct ext4_xattr_entry *entry, *last, *first;
1143         struct buffer_head *bh = NULL;
1144         struct ext4_xattr_ibody_find *is = NULL;
1145         struct ext4_xattr_block_find *bs = NULL;
1146         char *buffer = NULL, *b_entry_name = NULL;
1147         size_t min_offs, free;
1148         int total_ino, total_blk;
1149         void *base, *start, *end;
1150         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1151         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1152
1153         down_write(&EXT4_I(inode)->xattr_sem);
1154 retry:
1155         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1156                 up_write(&EXT4_I(inode)->xattr_sem);
1157                 return 0;
1158         }
1159
1160         header = IHDR(inode, raw_inode);
1161         entry = IFIRST(header);
1162
1163         /*
1164          * Check if enough free space is available in the inode to shift the
1165          * entries ahead by new_extra_isize.
1166          */
1167
1168         base = start = entry;
1169         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1170         min_offs = end - base;
1171         last = entry;
1172         total_ino = sizeof(struct ext4_xattr_ibody_header);
1173
1174         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1175         if (free >= new_extra_isize) {
1176                 entry = IFIRST(header);
1177                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1178                                 - new_extra_isize, (void *)raw_inode +
1179                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1180                                 (void *)header, total_ino,
1181                                 inode->i_sb->s_blocksize);
1182                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1183                 error = 0;
1184                 goto cleanup;
1185         }
1186
1187         /*
1188          * Enough free space isn't available in the inode, check if
1189          * EA block can hold new_extra_isize bytes.
1190          */
1191         if (EXT4_I(inode)->i_file_acl) {
1192                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1193                 error = -EIO;
1194                 if (!bh)
1195                         goto cleanup;
1196                 if (ext4_xattr_check_block(bh)) {
1197                         EXT4_ERROR_INODE(inode, "bad block %llu",
1198                                          EXT4_I(inode)->i_file_acl);
1199                         error = -EIO;
1200                         goto cleanup;
1201                 }
1202                 base = BHDR(bh);
1203                 first = BFIRST(bh);
1204                 end = bh->b_data + bh->b_size;
1205                 min_offs = end - base;
1206                 free = ext4_xattr_free_space(first, &min_offs, base,
1207                                              &total_blk);
1208                 if (free < new_extra_isize) {
1209                         if (!tried_min_extra_isize && s_min_extra_isize) {
1210                                 tried_min_extra_isize++;
1211                                 new_extra_isize = s_min_extra_isize;
1212                                 brelse(bh);
1213                                 goto retry;
1214                         }
1215                         error = -1;
1216                         goto cleanup;
1217                 }
1218         } else {
1219                 free = inode->i_sb->s_blocksize;
1220         }
1221
1222         while (new_extra_isize > 0) {
1223                 size_t offs, size, entry_size;
1224                 struct ext4_xattr_entry *small_entry = NULL;
1225                 struct ext4_xattr_info i = {
1226                         .value = NULL,
1227                         .value_len = 0,
1228                 };
1229                 unsigned int total_size;  /* EA entry size + value size */
1230                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1231                 unsigned int min_total_size = ~0U;
1232
1233                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1234                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1235                 if (!is || !bs) {
1236                         error = -ENOMEM;
1237                         goto cleanup;
1238                 }
1239
1240                 is->s.not_found = -ENODATA;
1241                 bs->s.not_found = -ENODATA;
1242                 is->iloc.bh = NULL;
1243                 bs->bh = NULL;
1244
1245                 last = IFIRST(header);
1246                 /* Find the entry best suited to be pushed into EA block */
1247                 entry = NULL;
1248                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1249                         total_size =
1250                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1251                                         EXT4_XATTR_LEN(last->e_name_len);
1252                         if (total_size <= free && total_size < min_total_size) {
1253                                 if (total_size < new_extra_isize) {
1254                                         small_entry = last;
1255                                 } else {
1256                                         entry = last;
1257                                         min_total_size = total_size;
1258                                 }
1259                         }
1260                 }
1261
1262                 if (entry == NULL) {
1263                         if (small_entry) {
1264                                 entry = small_entry;
1265                         } else {
1266                                 if (!tried_min_extra_isize &&
1267                                     s_min_extra_isize) {
1268                                         tried_min_extra_isize++;
1269                                         new_extra_isize = s_min_extra_isize;
1270                                         goto retry;
1271                                 }
1272                                 error = -1;
1273                                 goto cleanup;
1274                         }
1275                 }
1276                 offs = le16_to_cpu(entry->e_value_offs);
1277                 size = le32_to_cpu(entry->e_value_size);
1278                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1279                 i.name_index = entry->e_name_index,
1280                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1281                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1282                 if (!buffer || !b_entry_name) {
1283                         error = -ENOMEM;
1284                         goto cleanup;
1285                 }
1286                 /* Save the entry name and the entry value */
1287                 memcpy(buffer, (void *)IFIRST(header) + offs,
1288                        EXT4_XATTR_SIZE(size));
1289                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1290                 b_entry_name[entry->e_name_len] = '\0';
1291                 i.name = b_entry_name;
1292
1293                 error = ext4_get_inode_loc(inode, &is->iloc);
1294                 if (error)
1295                         goto cleanup;
1296
1297                 error = ext4_xattr_ibody_find(inode, &i, is);
1298                 if (error)
1299                         goto cleanup;
1300
1301                 /* Remove the chosen entry from the inode */
1302                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1303                 if (error)
1304                         goto cleanup;
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(inode, "block %llu read error",
1376                                  EXT4_I(inode)->i_file_acl);
1377                 goto cleanup;
1378         }
1379         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1380             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1381                 EXT4_ERROR_INODE(inode, "bad block %llu",
1382                                  EXT4_I(inode)->i_file_acl);
1383                 goto cleanup;
1384         }
1385         ext4_xattr_release_block(handle, inode, bh);
1386         EXT4_I(inode)->i_file_acl = 0;
1387
1388 cleanup:
1389         brelse(bh);
1390 }
1391
1392 /*
1393  * ext4_xattr_put_super()
1394  *
1395  * This is called when a file system is unmounted.
1396  */
1397 void
1398 ext4_xattr_put_super(struct super_block *sb)
1399 {
1400         mb_cache_shrink(sb->s_bdev);
1401 }
1402
1403 /*
1404  * ext4_xattr_cache_insert()
1405  *
1406  * Create a new entry in the extended attribute cache, and insert
1407  * it unless such an entry is already in the cache.
1408  *
1409  * Returns 0, or a negative error number on failure.
1410  */
1411 static void
1412 ext4_xattr_cache_insert(struct buffer_head *bh)
1413 {
1414         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1415         struct mb_cache_entry *ce;
1416         int error;
1417
1418         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1419         if (!ce) {
1420                 ea_bdebug(bh, "out of memory");
1421                 return;
1422         }
1423         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1424         if (error) {
1425                 mb_cache_entry_free(ce);
1426                 if (error == -EBUSY) {
1427                         ea_bdebug(bh, "already in cache");
1428                         error = 0;
1429                 }
1430         } else {
1431                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1432                 mb_cache_entry_release(ce);
1433         }
1434 }
1435
1436 /*
1437  * ext4_xattr_cmp()
1438  *
1439  * Compare two extended attribute blocks for equality.
1440  *
1441  * Returns 0 if the blocks are equal, 1 if they differ, and
1442  * a negative error number on errors.
1443  */
1444 static int
1445 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1446                struct ext4_xattr_header *header2)
1447 {
1448         struct ext4_xattr_entry *entry1, *entry2;
1449
1450         entry1 = ENTRY(header1+1);
1451         entry2 = ENTRY(header2+1);
1452         while (!IS_LAST_ENTRY(entry1)) {
1453                 if (IS_LAST_ENTRY(entry2))
1454                         return 1;
1455                 if (entry1->e_hash != entry2->e_hash ||
1456                     entry1->e_name_index != entry2->e_name_index ||
1457                     entry1->e_name_len != entry2->e_name_len ||
1458                     entry1->e_value_size != entry2->e_value_size ||
1459                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1460                         return 1;
1461                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1462                         return -EIO;
1463                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1464                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1465                            le32_to_cpu(entry1->e_value_size)))
1466                         return 1;
1467
1468                 entry1 = EXT4_XATTR_NEXT(entry1);
1469                 entry2 = EXT4_XATTR_NEXT(entry2);
1470         }
1471         if (!IS_LAST_ENTRY(entry2))
1472                 return 1;
1473         return 0;
1474 }
1475
1476 /*
1477  * ext4_xattr_cache_find()
1478  *
1479  * Find an identical extended attribute block.
1480  *
1481  * Returns a pointer to the block found, or NULL if such a block was
1482  * not found or an error occurred.
1483  */
1484 static struct buffer_head *
1485 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1486                       struct mb_cache_entry **pce)
1487 {
1488         __u32 hash = le32_to_cpu(header->h_hash);
1489         struct mb_cache_entry *ce;
1490
1491         if (!header->h_hash)
1492                 return NULL;  /* never share */
1493         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1494 again:
1495         ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1496                                        hash);
1497         while (ce) {
1498                 struct buffer_head *bh;
1499
1500                 if (IS_ERR(ce)) {
1501                         if (PTR_ERR(ce) == -EAGAIN)
1502                                 goto again;
1503                         break;
1504                 }
1505                 bh = sb_bread(inode->i_sb, ce->e_block);
1506                 if (!bh) {
1507                         EXT4_ERROR_INODE(inode, "block %lu read error",
1508                                          (unsigned long) ce->e_block);
1509                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1510                                 EXT4_XATTR_REFCOUNT_MAX) {
1511                         ea_idebug(inode, "block %lu refcount %d>=%d",
1512                                   (unsigned long) ce->e_block,
1513                                   le32_to_cpu(BHDR(bh)->h_refcount),
1514                                           EXT4_XATTR_REFCOUNT_MAX);
1515                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1516                         *pce = ce;
1517                         return bh;
1518                 }
1519                 brelse(bh);
1520                 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1521         }
1522         return NULL;
1523 }
1524
1525 #define NAME_HASH_SHIFT 5
1526 #define VALUE_HASH_SHIFT 16
1527
1528 /*
1529  * ext4_xattr_hash_entry()
1530  *
1531  * Compute the hash of an extended attribute.
1532  */
1533 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1534                                          struct ext4_xattr_entry *entry)
1535 {
1536         __u32 hash = 0;
1537         char *name = entry->e_name;
1538         int n;
1539
1540         for (n = 0; n < entry->e_name_len; n++) {
1541                 hash = (hash << NAME_HASH_SHIFT) ^
1542                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1543                        *name++;
1544         }
1545
1546         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1547                 __le32 *value = (__le32 *)((char *)header +
1548                         le16_to_cpu(entry->e_value_offs));
1549                 for (n = (le32_to_cpu(entry->e_value_size) +
1550                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1551                         hash = (hash << VALUE_HASH_SHIFT) ^
1552                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1553                                le32_to_cpu(*value++);
1554                 }
1555         }
1556         entry->e_hash = cpu_to_le32(hash);
1557 }
1558
1559 #undef NAME_HASH_SHIFT
1560 #undef VALUE_HASH_SHIFT
1561
1562 #define BLOCK_HASH_SHIFT 16
1563
1564 /*
1565  * ext4_xattr_rehash()
1566  *
1567  * Re-compute the extended attribute hash value after an entry has changed.
1568  */
1569 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1570                               struct ext4_xattr_entry *entry)
1571 {
1572         struct ext4_xattr_entry *here;
1573         __u32 hash = 0;
1574
1575         ext4_xattr_hash_entry(header, entry);
1576         here = ENTRY(header+1);
1577         while (!IS_LAST_ENTRY(here)) {
1578                 if (!here->e_hash) {
1579                         /* Block is not shared if an entry's hash value == 0 */
1580                         hash = 0;
1581                         break;
1582                 }
1583                 hash = (hash << BLOCK_HASH_SHIFT) ^
1584                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1585                        le32_to_cpu(here->e_hash);
1586                 here = EXT4_XATTR_NEXT(here);
1587         }
1588         header->h_hash = cpu_to_le32(hash);
1589 }
1590
1591 #undef BLOCK_HASH_SHIFT
1592
1593 int __init
1594 ext4_init_xattr(void)
1595 {
1596         ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1597         if (!ext4_xattr_cache)
1598                 return -ENOMEM;
1599         return 0;
1600 }
1601
1602 void
1603 ext4_exit_xattr(void)
1604 {
1605         if (ext4_xattr_cache)
1606                 mb_cache_destroy(ext4_xattr_cache);
1607         ext4_xattr_cache = NULL;
1608 }