fs/ext4/xattr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/fs/ext4/xattr.c
   4  *
   5  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   6  *
   7  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   8  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   9  * Extended attributes for symlinks and special files added per
  10  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  11  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  12  *  Red Hat Inc.
  13  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  14  *  and Andreas Gruenbacher <agruen@suse.de>.
  15  */
  16
  17 /*
  18  * Extended attributes are stored directly in inodes (on file systems with
  19  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  20  * field contains the block number if an inode uses an additional block. All
  21  * attributes must fit in the inode and one additional block. Blocks that
  22  * contain the identical set of attributes may be shared among several inodes.
  23  * Identical blocks are detected by keeping a cache of blocks that have
  24  * recently been accessed.
  25  *
  26  * The attributes in inodes and on blocks have a different header; the entries
  27  * are stored in the same format:
  28  *
  29  *   +------------------+
  30  *   | header           |
  31  *   | entry 1          | |
  32  *   | entry 2          | | growing downwards
  33  *   | entry 3          | v
  34  *   | four null bytes  |
  35  *   | . . .            |
  36  *   | value 1          | ^
  37  *   | value 3          | | growing upwards
  38  *   | value 2          | |
  39  *   +------------------+
  40  *
  41  * The header is followed by multiple entry descriptors. In disk blocks, the
  42  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  43  * attribute values are aligned to the end of the block in no specific order.
  44  *
  45  * Locking strategy
  46  * ----------------
  47  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  48  * EA blocks are only changed if they are exclusive to an inode, so
  49  * holding xattr_sem also means that nothing but the EA block's reference
  50  * count can change. Multiple writers to the same block are synchronized
  51  * by the buffer lock.
  52  */
  53
  54 #include <linux/init.h>
  55 #include <linux/fs.h>
  56 #include <linux/slab.h>
  57 #include <linux/mbcache.h>
  58 #include <linux/quotaops.h>
  59 #include <linux/iversion.h>
  60 #include "ext4_jbd2.h"
  61 #include "ext4.h"
  62 #include "xattr.h"
  63 #include "acl.h"
  64
  65 #ifdef EXT4_XATTR_DEBUG
  66 # define ea_idebug(inode, fmt, ...)                                     \
  67         printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",                    \
  68                inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
  69 # define ea_bdebug(bh, fmt, ...)                                        \
  70         printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",                   \
  71                bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
  72 #else
  73 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  74 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  75 #endif
  76
  77 static void ext4_xattr_block_cache_insert(struct mb_cache *,
  78                                           struct buffer_head *);
  79 static struct buffer_head *
  80 ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
  81                             struct mb_cache_entry **);
  82 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
  83                                     size_t value_count);
  84 static void ext4_xattr_rehash(struct ext4_xattr_header *);
  85
  86 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
  87         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  88 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  89         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  90         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  91 #endif
  92         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
  93 #ifdef CONFIG_EXT4_FS_SECURITY
  94         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
  95 #endif
  96 };
  97
  98 const struct xattr_handler *ext4_xattr_handlers[] = {
  99         &ext4_xattr_user_handler,
 100         &ext4_xattr_trusted_handler,
 101 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 102         &posix_acl_access_xattr_handler,
 103         &posix_acl_default_xattr_handler,
 104 #endif
 105 #ifdef CONFIG_EXT4_FS_SECURITY
 106         &ext4_xattr_security_handler,
 107 #endif
 108         NULL
 109 };
 110
 111 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 112                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 113
 114 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 115                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 116
 117 static int
 118 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 119                         struct inode *inode);
 120
 121 #ifdef CONFIG_LOCKDEP
 122 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 123 {
 124         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 125 }
 126 #endif
 127
 128 static __le32 ext4_xattr_block_csum(struct inode *inode,
 129                                     sector_t block_nr,
 130                                     struct ext4_xattr_header *hdr)
 131 {
 132         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 133         __u32 csum;
 134         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 135         __u32 dummy_csum = 0;
 136         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 137
 138         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 139                            sizeof(dsk_block_nr));
 140         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 141         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 142         offset += sizeof(dummy_csum);
 143         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 144                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 145
 146         return cpu_to_le32(csum);
 147 }
 148
 149 static int ext4_xattr_block_csum_verify(struct inode *inode,
 150                                         struct buffer_head *bh)
 151 {
 152         struct ext4_xattr_header *hdr = BHDR(bh);
 153         int ret = 1;
 154
 155         if (ext4_has_metadata_csum(inode->i_sb)) {
 156                 lock_buffer(bh);
 157                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 158                                                         bh->b_blocknr, hdr));
 159                 unlock_buffer(bh);
 160         }
 161         return ret;
 162 }
 163
 164 static void ext4_xattr_block_csum_set(struct inode *inode,
 165                                       struct buffer_head *bh)
 166 {
 167         if (ext4_has_metadata_csum(inode->i_sb))
 168                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 169                                                 bh->b_blocknr, BHDR(bh));
 170 }
 171
 172 static inline const struct xattr_handler *
 173 ext4_xattr_handler(int name_index)
 174 {
 175         const struct xattr_handler *handler = NULL;
 176
 177         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 178                 handler = ext4_xattr_handler_map[name_index];
 179         return handler;
 180 }
 181
 182 static int
 183 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
 184                          void *value_start)
 185 {
 186         struct ext4_xattr_entry *e = entry;
 187
 188         /* Find the end of the names list */
 189         while (!IS_LAST_ENTRY(e)) {
 190                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 191                 if ((void *)next >= end)
 192                         return -EFSCORRUPTED;
 193                 e = next;
 194         }
 195
 196         /* Check the values */
 197         while (!IS_LAST_ENTRY(entry)) {
 198                 if (entry->e_value_size != 0 &&
 199                     entry->e_value_inum == 0) {
 200                         u16 offs = le16_to_cpu(entry->e_value_offs);
 201                         u32 size = le32_to_cpu(entry->e_value_size);
 202                         void *value;
 203
 204                         /*
 205                          * The value cannot overlap the names, and the value
 206                          * with padding cannot extend beyond 'end'.  Check both
 207                          * the padded and unpadded sizes, since the size may
 208                          * overflow to 0 when adding padding.
 209                          */
 210                         if (offs > end - value_start)
 211                                 return -EFSCORRUPTED;
 212                         value = value_start + offs;
 213                         if (value < (void *)e + sizeof(u32) ||
 214                             size > end - value ||
 215                             EXT4_XATTR_SIZE(size) > end - value)
 216                                 return -EFSCORRUPTED;
 217                 }
 218                 entry = EXT4_XATTR_NEXT(entry);
 219         }
 220
 221         return 0;
 222 }
 223
 224 static inline int
 225 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 226 {
 227         int error;
 228
 229         if (buffer_verified(bh))
 230                 return 0;
 231
 232         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 233             BHDR(bh)->h_blocks != cpu_to_le32(1))
 234                 return -EFSCORRUPTED;
 235         if (!ext4_xattr_block_csum_verify(inode, bh))
 236                 return -EFSBADCRC;
 237         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 238                                          bh->b_data);
 239         if (!error)
 240                 set_buffer_verified(bh);
 241         return error;
 242 }
 243
 244 static int
 245 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 246                          void *end, const char *function, unsigned int line)
 247 {
 248         int error = -EFSCORRUPTED;
 249
 250         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 251             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 252                 goto errout;
 253         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 254 errout:
 255         if (error)
 256                 __ext4_error_inode(inode, function, line, 0,
 257                                    "corrupted in-inode xattr");
 258         return error;
 259 }
 260
 261 #define xattr_check_inode(inode, header, end) \
 262         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 263
 264 static int
 265 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 266                       const char *name, int sorted)
 267 {
 268         struct ext4_xattr_entry *entry;
 269         size_t name_len;
 270         int cmp = 1;
 271
 272         if (name == NULL)
 273                 return -EINVAL;
 274         name_len = strlen(name);
 275         entry = *pentry;
 276         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 277                 cmp = name_index - entry->e_name_index;
 278                 if (!cmp)
 279                         cmp = name_len - entry->e_name_len;
 280                 if (!cmp)
 281                         cmp = memcmp(name, entry->e_name, name_len);
 282                 if (cmp <= 0 && (sorted || cmp == 0))
 283                         break;
 284         }
 285         *pentry = entry;
 286         return cmp ? -ENODATA : 0;
 287 }
 288
 289 static u32
 290 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 291 {
 292         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 293 }
 294
 295 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 296 {
 297         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 298                 (u32) inode_peek_iversion_raw(ea_inode);
 299 }
 300
 301 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 302 {
 303         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 304         inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
 305 }
 306
 307 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 308 {
 309         return (u32)ea_inode->i_atime.tv_sec;
 310 }
 311
 312 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 313 {
 314         ea_inode->i_atime.tv_sec = hash;
 315 }
 316
 317 /*
 318  * Read the EA value from an inode.
 319  */
 320 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 321 {
 322         int blocksize = 1 << ea_inode->i_blkbits;
 323         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 324         int tail_size = (size % blocksize) ?: blocksize;
 325         struct buffer_head *bhs_inline[8];
 326         struct buffer_head **bhs = bhs_inline;
 327         int i, ret;
 328
 329         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 330                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 331                 if (!bhs)
 332                         return -ENOMEM;
 333         }
 334
 335         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 336                                true /* wait */, bhs);
 337         if (ret)
 338                 goto free_bhs;
 339
 340         for (i = 0; i < bh_count; i++) {
 341                 /* There shouldn't be any holes in ea_inode. */
 342                 if (!bhs[i]) {
 343                         ret = -EFSCORRUPTED;
 344                         goto put_bhs;
 345                 }
 346                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 347                        i < bh_count - 1 ? blocksize : tail_size);
 348         }
 349         ret = 0;
 350 put_bhs:
 351         for (i = 0; i < bh_count; i++)
 352                 brelse(bhs[i]);
 353 free_bhs:
 354         if (bhs != bhs_inline)
 355                 kfree(bhs);
 356         return ret;
 357 }
 358
 359 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 360
 361 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 362                                  u32 ea_inode_hash, struct inode **ea_inode)
 363 {
 364         struct inode *inode;
 365         int err;
 366
 367         inode = ext4_iget(parent->i_sb, ea_ino);
 368         if (IS_ERR(inode)) {
 369                 err = PTR_ERR(inode);
 370                 ext4_error(parent->i_sb,
 371                            "error while reading EA inode %lu err=%d", ea_ino,
 372                            err);
 373                 return err;
 374         }
 375
 376         if (is_bad_inode(inode)) {
 377                 ext4_error(parent->i_sb,
 378                            "error while reading EA inode %lu is_bad_inode",
 379                            ea_ino);
 380                 err = -EIO;
 381                 goto error;
 382         }
 383
 384         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 385                 ext4_error(parent->i_sb,
 386                            "EA inode %lu does not have EXT4_EA_INODE_FL flag",
 387                             ea_ino);
 388                 err = -EINVAL;
 389                 goto error;
 390         }
 391
 392         ext4_xattr_inode_set_class(inode);
 393
 394         /*
 395          * Check whether this is an old Lustre-style xattr inode. Lustre
 396          * implementation does not have hash validation, rather it has a
 397          * backpointer from ea_inode to the parent inode.
 398          */
 399         if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
 400             EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
 401             inode->i_generation == parent->i_generation) {
 402                 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
 403                 ext4_xattr_inode_set_ref(inode, 1);
 404         } else {
 405                 inode_lock(inode);
 406                 inode->i_flags |= S_NOQUOTA;
 407                 inode_unlock(inode);
 408         }
 409
 410         *ea_inode = inode;
 411         return 0;
 412 error:
 413         iput(inode);
 414         return err;
 415 }
 416
 417 static int
 418 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 419                                struct ext4_xattr_entry *entry, void *buffer,
 420                                size_t size)
 421 {
 422         u32 hash;
 423
 424         /* Verify stored hash matches calculated hash. */
 425         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 426         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 427                 return -EFSCORRUPTED;
 428
 429         if (entry) {
 430                 __le32 e_hash, tmp_data;
 431
 432                 /* Verify entry hash. */
 433                 tmp_data = cpu_to_le32(hash);
 434                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 435                                                &tmp_data, 1);
 436                 if (e_hash != entry->e_hash)
 437                         return -EFSCORRUPTED;
 438         }
 439         return 0;
 440 }
 441
 442 /*
 443  * Read xattr value from the EA inode.
 444  */
 445 static int
 446 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 447                      void *buffer, size_t size)
 448 {
 449         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 450         struct inode *ea_inode;
 451         int err;
 452
 453         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 454                                     le32_to_cpu(entry->e_hash), &ea_inode);
 455         if (err) {
 456                 ea_inode = NULL;
 457                 goto out;
 458         }
 459
 460         if (i_size_read(ea_inode) != size) {
 461                 ext4_warning_inode(ea_inode,
 462                                    "ea_inode file size=%llu entry size=%zu",
 463                                    i_size_read(ea_inode), size);
 464                 err = -EFSCORRUPTED;
 465                 goto out;
 466         }
 467
 468         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 469         if (err)
 470                 goto out;
 471
 472         if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
 473                 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
 474                                                      size);
 475                 if (err) {
 476                         ext4_warning_inode(ea_inode,
 477                                            "EA inode hash validation failed");
 478                         goto out;
 479                 }
 480
 481                 if (ea_inode_cache)
 482                         mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 483                                         ext4_xattr_inode_get_hash(ea_inode),
 484                                         ea_inode->i_ino, true /* reusable */);
 485         }
 486 out:
 487         iput(ea_inode);
 488         return err;
 489 }
 490
 491 static int
 492 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 493                      void *buffer, size_t buffer_size)
 494 {
 495         struct buffer_head *bh = NULL;
 496         struct ext4_xattr_entry *entry;
 497         size_t size;
 498         int error;
 499         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 500
 501         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 502                   name_index, name, buffer, (long)buffer_size);
 503
 504         error = -ENODATA;
 505         if (!EXT4_I(inode)->i_file_acl)
 506                 goto cleanup;
 507         ea_idebug(inode, "reading block %llu",
 508                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 509         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 510         if (!bh)
 511                 goto cleanup;
 512         ea_bdebug(bh, "b_count=%d, refcount=%d",
 513                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 514         if (ext4_xattr_check_block(inode, bh)) {
 515                 EXT4_ERROR_INODE(inode, "bad block %llu",
 516                                  EXT4_I(inode)->i_file_acl);
 517                 error = -EFSCORRUPTED;
 518                 goto cleanup;
 519         }
 520         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 521         entry = BFIRST(bh);
 522         error = ext4_xattr_find_entry(&entry, name_index, name, 1);
 523         if (error)
 524                 goto cleanup;
 525         size = le32_to_cpu(entry->e_value_size);
 526         if (buffer) {
 527                 error = -ERANGE;
 528                 if (size > buffer_size)
 529                         goto cleanup;
 530                 if (entry->e_value_inum) {
 531                         error = ext4_xattr_inode_get(inode, entry, buffer,
 532                                                      size);
 533                         if (error)
 534                                 goto cleanup;
 535                 } else {
 536                         memcpy(buffer, bh->b_data +
 537                                le16_to_cpu(entry->e_value_offs), size);
 538                 }
 539         }
 540         error = size;
 541
 542 cleanup:
 543         brelse(bh);
 544         return error;
 545 }
 546
 547 int
 548 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 549                      void *buffer, size_t buffer_size)
 550 {
 551         struct ext4_xattr_ibody_header *header;
 552         struct ext4_xattr_entry *entry;
 553         struct ext4_inode *raw_inode;
 554         struct ext4_iloc iloc;
 555         size_t size;
 556         void *end;
 557         int error;
 558
 559         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 560                 return -ENODATA;
 561         error = ext4_get_inode_loc(inode, &iloc);
 562         if (error)
 563                 return error;
 564         raw_inode = ext4_raw_inode(&iloc);
 565         header = IHDR(inode, raw_inode);
 566         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 567         error = xattr_check_inode(inode, header, end);
 568         if (error)
 569                 goto cleanup;
 570         entry = IFIRST(header);
 571         error = ext4_xattr_find_entry(&entry, name_index, name, 0);
 572         if (error)
 573                 goto cleanup;
 574         size = le32_to_cpu(entry->e_value_size);
 575         if (buffer) {
 576                 error = -ERANGE;
 577                 if (size > buffer_size)
 578                         goto cleanup;
 579                 if (entry->e_value_inum) {
 580                         error = ext4_xattr_inode_get(inode, entry, buffer,
 581                                                      size);
 582                         if (error)
 583                                 goto cleanup;
 584                 } else {
 585                         memcpy(buffer, (void *)IFIRST(header) +
 586                                le16_to_cpu(entry->e_value_offs), size);
 587                 }
 588         }
 589         error = size;
 590
 591 cleanup:
 592         brelse(iloc.bh);
 593         return error;
 594 }
 595
 596 /*
 597  * ext4_xattr_get()
 598  *
 599  * Copy an extended attribute into the buffer
 600  * provided, or compute the buffer size required.
 601  * Buffer is NULL to compute the size of the buffer required.
 602  *
 603  * Returns a negative error number on failure, or the number of bytes
 604  * used / required on success.
 605  */
 606 int
 607 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 608                void *buffer, size_t buffer_size)
 609 {
 610         int error;
 611
 612         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 613                 return -EIO;
 614
 615         if (strlen(name) > 255)
 616                 return -ERANGE;
 617
 618         down_read(&EXT4_I(inode)->xattr_sem);
 619         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 620                                      buffer_size);
 621         if (error == -ENODATA)
 622                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 623                                              buffer_size);
 624         up_read(&EXT4_I(inode)->xattr_sem);
 625         return error;
 626 }
 627
 628 static int
 629 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 630                         char *buffer, size_t buffer_size)
 631 {
 632         size_t rest = buffer_size;
 633
 634         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 635                 const struct xattr_handler *handler =
 636                         ext4_xattr_handler(entry->e_name_index);
 637
 638                 if (handler && (!handler->list || handler->list(dentry))) {
 639                         const char *prefix = handler->prefix ?: handler->name;
 640                         size_t prefix_len = strlen(prefix);
 641                         size_t size = prefix_len + entry->e_name_len + 1;
 642
 643                         if (buffer) {
 644                                 if (size > rest)
 645                                         return -ERANGE;
 646                                 memcpy(buffer, prefix, prefix_len);
 647                                 buffer += prefix_len;
 648                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 649                                 buffer += entry->e_name_len;
 650                                 *buffer++ = 0;
 651                         }
 652                         rest -= size;
 653                 }
 654         }
 655         return buffer_size - rest;  /* total size */
 656 }
 657
 658 static int
 659 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 660 {
 661         struct inode *inode = d_inode(dentry);
 662         struct buffer_head *bh = NULL;
 663         int error;
 664
 665         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 666                   buffer, (long)buffer_size);
 667
 668         error = 0;
 669         if (!EXT4_I(inode)->i_file_acl)
 670                 goto cleanup;
 671         ea_idebug(inode, "reading block %llu",
 672                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 673         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 674         error = -EIO;
 675         if (!bh)
 676                 goto cleanup;
 677         ea_bdebug(bh, "b_count=%d, refcount=%d",
 678                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 679         if (ext4_xattr_check_block(inode, bh)) {
 680                 EXT4_ERROR_INODE(inode, "bad block %llu",
 681                                  EXT4_I(inode)->i_file_acl);
 682                 error = -EFSCORRUPTED;
 683                 goto cleanup;
 684         }
 685         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 686         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 687
 688 cleanup:
 689         brelse(bh);
 690
 691         return error;
 692 }
 693
 694 static int
 695 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 696 {
 697         struct inode *inode = d_inode(dentry);
 698         struct ext4_xattr_ibody_header *header;
 699         struct ext4_inode *raw_inode;
 700         struct ext4_iloc iloc;
 701         void *end;
 702         int error;
 703
 704         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 705                 return 0;
 706         error = ext4_get_inode_loc(inode, &iloc);
 707         if (error)
 708                 return error;
 709         raw_inode = ext4_raw_inode(&iloc);
 710         header = IHDR(inode, raw_inode);
 711         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 712         error = xattr_check_inode(inode, header, end);
 713         if (error)
 714                 goto cleanup;
 715         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 716                                         buffer, buffer_size);
 717
 718 cleanup:
 719         brelse(iloc.bh);
 720         return error;
 721 }
 722
 723 /*
 724  * Inode operation listxattr()
 725  *
 726  * d_inode(dentry)->i_rwsem: don't care
 727  *
 728  * Copy a list of attribute names into the buffer
 729  * provided, or compute the buffer size required.
 730  * Buffer is NULL to compute the size of the buffer required.
 731  *
 732  * Returns a negative error number on failure, or the number of bytes
 733  * used / required on success.
 734  */
 735 ssize_t
 736 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 737 {
 738         int ret, ret2;
 739
 740         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 741         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 742         if (ret < 0)
 743                 goto errout;
 744         if (buffer) {
 745                 buffer += ret;
 746                 buffer_size -= ret;
 747         }
 748         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 749         if (ret < 0)
 750                 goto errout;
 751         ret += ret2;
 752 errout:
 753         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 754         return ret;
 755 }
 756
 757 /*
 758  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 759  * not set, set it.
 760  */
 761 static void ext4_xattr_update_super_block(handle_t *handle,
 762                                           struct super_block *sb)
 763 {
 764         if (ext4_has_feature_xattr(sb))
 765                 return;
 766
 767         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 768         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 769                 ext4_set_feature_xattr(sb);
 770                 ext4_handle_dirty_super(handle, sb);
 771         }
 772 }
 773
 774 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 775 {
 776         struct ext4_iloc iloc = { .bh = NULL };
 777         struct buffer_head *bh = NULL;
 778         struct ext4_inode *raw_inode;
 779         struct ext4_xattr_ibody_header *header;
 780         struct ext4_xattr_entry *entry;
 781         qsize_t ea_inode_refs = 0;
 782         void *end;
 783         int ret;
 784
 785         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 786
 787         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 788                 ret = ext4_get_inode_loc(inode, &iloc);
 789                 if (ret)
 790                         goto out;
 791                 raw_inode = ext4_raw_inode(&iloc);
 792                 header = IHDR(inode, raw_inode);
 793                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 794                 ret = xattr_check_inode(inode, header, end);
 795                 if (ret)
 796                         goto out;
 797
 798                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 799                      entry = EXT4_XATTR_NEXT(entry))
 800                         if (entry->e_value_inum)
 801                                 ea_inode_refs++;
 802         }
 803
 804         if (EXT4_I(inode)->i_file_acl) {
 805                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 806                 if (!bh) {
 807                         ret = -EIO;
 808                         goto out;
 809                 }
 810
 811                 if (ext4_xattr_check_block(inode, bh)) {
 812                         ret = -EFSCORRUPTED;
 813                         goto out;
 814                 }
 815
 816                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 817                      entry = EXT4_XATTR_NEXT(entry))
 818                         if (entry->e_value_inum)
 819                                 ea_inode_refs++;
 820         }
 821         *usage = ea_inode_refs + 1;
 822         ret = 0;
 823 out:
 824         brelse(iloc.bh);
 825         brelse(bh);
 826         return ret;
 827 }
 828
 829 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 830 {
 831         struct super_block *sb = inode->i_sb;
 832         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 833                                     inode->i_blkbits);
 834         size_t mask = ~(cluster_size - 1);
 835
 836         return (length + cluster_size - 1) & mask;
 837 }
 838
 839 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 840 {
 841         int err;
 842
 843         err = dquot_alloc_inode(inode);
 844         if (err)
 845                 return err;
 846         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 847         if (err)
 848                 dquot_free_inode(inode);
 849         return err;
 850 }
 851
 852 static void ext4_xattr_inode_free_quota(struct inode *parent,
 853                                         struct inode *ea_inode,
 854                                         size_t len)
 855 {
 856         if (ea_inode &&
 857             ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
 858                 return;
 859         dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
 860         dquot_free_inode(parent);
 861 }
 862
 863 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 864                              struct buffer_head *block_bh, size_t value_len,
 865                              bool is_create)
 866 {
 867         int credits;
 868         int blocks;
 869
 870         /*
 871          * 1) Owner inode update
 872          * 2) Ref count update on old xattr block
 873          * 3) new xattr block
 874          * 4) block bitmap update for new xattr block
 875          * 5) group descriptor for new xattr block
 876          * 6) block bitmap update for old xattr block
 877          * 7) group descriptor for old block
 878          *
 879          * 6 & 7 can happen if we have two racing threads T_a and T_b
 880          * which are each trying to set an xattr on inodes I_a and I_b
 881          * which were both initially sharing an xattr block.
 882          */
 883         credits = 7;
 884
 885         /* Quota updates. */
 886         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 887
 888         /*
 889          * In case of inline data, we may push out the data to a block,
 890          * so we need to reserve credits for this eventuality
 891          */
 892         if (inode && ext4_has_inline_data(inode))
 893                 credits += ext4_writepage_trans_blocks(inode) + 1;
 894
 895         /* We are done if ea_inode feature is not enabled. */
 896         if (!ext4_has_feature_ea_inode(sb))
 897                 return credits;
 898
 899         /* New ea_inode, inode map, block bitmap, group descriptor. */
 900         credits += 4;
 901
 902         /* Data blocks. */
 903         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 904
 905         /* Indirection block or one level of extent tree. */
 906         blocks += 1;
 907
 908         /* Block bitmap and group descriptor updates for each block. */
 909         credits += blocks * 2;
 910
 911         /* Blocks themselves. */
 912         credits += blocks;
 913
 914         if (!is_create) {
 915                 /* Dereference ea_inode holding old xattr value.
 916                  * Old ea_inode, inode map, block bitmap, group descriptor.
 917                  */
 918                 credits += 4;
 919
 920                 /* Data blocks for old ea_inode. */
 921                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 922
 923                 /* Indirection block or one level of extent tree for old
 924                  * ea_inode.
 925                  */
 926                 blocks += 1;
 927
 928                 /* Block bitmap and group descriptor updates for each block. */
 929                 credits += blocks * 2;
 930         }
 931
 932         /* We may need to clone the existing xattr block in which case we need
 933          * to increment ref counts for existing ea_inodes referenced by it.
 934          */
 935         if (block_bh) {
 936                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 937
 938                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 939                         if (entry->e_value_inum)
 940                                 /* Ref count update on ea_inode. */
 941                                 credits += 1;
 942         }
 943         return credits;
 944 }
 945
 946 static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 947                                      int credits, struct buffer_head *bh,
 948                                      bool dirty, bool block_csum)
 949 {
 950         int error;
 951
 952         if (!ext4_handle_valid(handle))
 953                 return 0;
 954
 955         if (handle->h_buffer_credits >= credits)
 956                 return 0;
 957
 958         error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
 959         if (!error)
 960                 return 0;
 961         if (error < 0) {
 962                 ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
 963                 return error;
 964         }
 965
 966         if (bh && dirty) {
 967                 if (block_csum)
 968                         ext4_xattr_block_csum_set(inode, bh);
 969                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
 970                 if (error) {
 971                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
 972                                      error);
 973                         return error;
 974                 }
 975         }
 976
 977         error = ext4_journal_restart(handle, credits);
 978         if (error) {
 979                 ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
 980                 return error;
 981         }
 982
 983         if (bh) {
 984                 error = ext4_journal_get_write_access(handle, bh);
 985                 if (error) {
 986                         ext4_warning(inode->i_sb,
 987                                      "Get write access failed (error %d)",
 988                                      error);
 989                         return error;
 990                 }
 991         }
 992         return 0;
 993 }
 994
 995 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 996                                        int ref_change)
 997 {
 998         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
 999         struct ext4_iloc iloc;
1000         s64 ref_count;
1001         u32 hash;
1002         int ret;
1003
1004         inode_lock(ea_inode);
1005
1006         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1007         if (ret) {
1008                 iloc.bh = NULL;
1009                 goto out;
1010         }
1011
1012         ref_count = ext4_xattr_inode_get_ref(ea_inode);
1013         ref_count += ref_change;
1014         ext4_xattr_inode_set_ref(ea_inode, ref_count);
1015
1016         if (ref_change > 0) {
1017                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1018                           ea_inode->i_ino, ref_count);
1019
1020                 if (ref_count == 1) {
1021                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1022                                   ea_inode->i_ino, ea_inode->i_nlink);
1023
1024                         set_nlink(ea_inode, 1);
1025                         ext4_orphan_del(handle, ea_inode);
1026
1027                         if (ea_inode_cache) {
1028                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1029                                 mb_cache_entry_create(ea_inode_cache,
1030                                                       GFP_NOFS, hash,
1031                                                       ea_inode->i_ino,
1032                                                       true /* reusable */);
1033                         }
1034                 }
1035         } else {
1036                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1037                           ea_inode->i_ino, ref_count);
1038
1039                 if (ref_count == 0) {
1040                         WARN_ONCE(ea_inode->i_nlink != 1,
1041                                   "EA inode %lu i_nlink=%u",
1042                                   ea_inode->i_ino, ea_inode->i_nlink);
1043
1044                         clear_nlink(ea_inode);
1045                         ext4_orphan_add(handle, ea_inode);
1046
1047                         if (ea_inode_cache) {
1048                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1049                                 mb_cache_entry_delete(ea_inode_cache, hash,
1050                                                       ea_inode->i_ino);
1051                         }
1052                 }
1053         }
1054
1055         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1056         iloc.bh = NULL;
1057         if (ret)
1058                 ext4_warning_inode(ea_inode,
1059                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1060 out:
1061         brelse(iloc.bh);
1062         inode_unlock(ea_inode);
1063         return ret;
1064 }
1065
1066 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1067 {
1068         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1069 }
1070
1071 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1072 {
1073         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1074 }
1075
1076 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1077                                         struct ext4_xattr_entry *first)
1078 {
1079         struct inode *ea_inode;
1080         struct ext4_xattr_entry *entry;
1081         struct ext4_xattr_entry *failed_entry;
1082         unsigned int ea_ino;
1083         int err, saved_err;
1084
1085         for (entry = first; !IS_LAST_ENTRY(entry);
1086              entry = EXT4_XATTR_NEXT(entry)) {
1087                 if (!entry->e_value_inum)
1088                         continue;
1089                 ea_ino = le32_to_cpu(entry->e_value_inum);
1090                 err = ext4_xattr_inode_iget(parent, ea_ino,
1091                                             le32_to_cpu(entry->e_hash),
1092                                             &ea_inode);
1093                 if (err)
1094                         goto cleanup;
1095                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1096                 if (err) {
1097                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1098                         iput(ea_inode);
1099                         goto cleanup;
1100                 }
1101                 iput(ea_inode);
1102         }
1103         return 0;
1104
1105 cleanup:
1106         saved_err = err;
1107         failed_entry = entry;
1108
1109         for (entry = first; entry != failed_entry;
1110              entry = EXT4_XATTR_NEXT(entry)) {
1111                 if (!entry->e_value_inum)
1112                         continue;
1113                 ea_ino = le32_to_cpu(entry->e_value_inum);
1114                 err = ext4_xattr_inode_iget(parent, ea_ino,
1115                                             le32_to_cpu(entry->e_hash),
1116                                             &ea_inode);
1117                 if (err) {
1118                         ext4_warning(parent->i_sb,
1119                                      "cleanup ea_ino %u iget error %d", ea_ino,
1120                                      err);
1121                         continue;
1122                 }
1123                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1124                 if (err)
1125                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1126                                            err);
1127                 iput(ea_inode);
1128         }
1129         return saved_err;
1130 }
1131
1132 static void
1133 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1134                              struct buffer_head *bh,
1135                              struct ext4_xattr_entry *first, bool block_csum,
1136                              struct ext4_xattr_inode_array **ea_inode_array,
1137                              int extra_credits, bool skip_quota)
1138 {
1139         struct inode *ea_inode;
1140         struct ext4_xattr_entry *entry;
1141         bool dirty = false;
1142         unsigned int ea_ino;
1143         int err;
1144         int credits;
1145
1146         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1147         credits = 2 + extra_credits;
1148
1149         for (entry = first; !IS_LAST_ENTRY(entry);
1150              entry = EXT4_XATTR_NEXT(entry)) {
1151                 if (!entry->e_value_inum)
1152                         continue;
1153                 ea_ino = le32_to_cpu(entry->e_value_inum);
1154                 err = ext4_xattr_inode_iget(parent, ea_ino,
1155                                             le32_to_cpu(entry->e_hash),
1156                                             &ea_inode);
1157                 if (err)
1158                         continue;
1159
1160                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1161                 if (err) {
1162                         ext4_warning_inode(ea_inode,
1163                                            "Expand inode array err=%d", err);
1164                         iput(ea_inode);
1165                         continue;
1166                 }
1167
1168                 err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
1169                                                 dirty, block_csum);
1170                 if (err) {
1171                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1172                                            err);
1173                         continue;
1174                 }
1175
1176                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1177                 if (err) {
1178                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1179                                            err);
1180                         continue;
1181                 }
1182
1183                 if (!skip_quota)
1184                         ext4_xattr_inode_free_quota(parent, ea_inode,
1185                                               le32_to_cpu(entry->e_value_size));
1186
1187                 /*
1188                  * Forget about ea_inode within the same transaction that
1189                  * decrements the ref count. This avoids duplicate decrements in
1190                  * case the rest of the work spills over to subsequent
1191                  * transactions.
1192                  */
1193                 entry->e_value_inum = 0;
1194                 entry->e_value_size = 0;
1195
1196                 dirty = true;
1197         }
1198
1199         if (dirty) {
1200                 /*
1201                  * Note that we are deliberately skipping csum calculation for
1202                  * the final update because we do not expect any journal
1203                  * restarts until xattr block is freed.
1204                  */
1205
1206                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1207                 if (err)
1208                         ext4_warning_inode(parent,
1209                                            "handle dirty metadata err=%d", err);
1210         }
1211 }
1212
1213 /*
1214  * Release the xattr block BH: If the reference count is > 1, decrement it;
1215  * otherwise free the block.
1216  */
1217 static void
1218 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1219                          struct buffer_head *bh,
1220                          struct ext4_xattr_inode_array **ea_inode_array,
1221                          int extra_credits)
1222 {
1223         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1224         u32 hash, ref;
1225         int error = 0;
1226
1227         BUFFER_TRACE(bh, "get_write_access");
1228         error = ext4_journal_get_write_access(handle, bh);
1229         if (error)
1230                 goto out;
1231
1232         lock_buffer(bh);
1233         hash = le32_to_cpu(BHDR(bh)->h_hash);
1234         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1235         if (ref == 1) {
1236                 ea_bdebug(bh, "refcount now=0; freeing");
1237                 /*
1238                  * This must happen under buffer lock for
1239                  * ext4_xattr_block_set() to reliably detect freed block
1240                  */
1241                 if (ea_block_cache)
1242                         mb_cache_entry_delete(ea_block_cache, hash,
1243                                               bh->b_blocknr);
1244                 get_bh(bh);
1245                 unlock_buffer(bh);
1246
1247                 if (ext4_has_feature_ea_inode(inode->i_sb))
1248                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1249                                                      BFIRST(bh),
1250                                                      true /* block_csum */,
1251                                                      ea_inode_array,
1252                                                      extra_credits,
1253                                                      true /* skip_quota */);
1254                 ext4_free_blocks(handle, inode, bh, 0, 1,
1255                                  EXT4_FREE_BLOCKS_METADATA |
1256                                  EXT4_FREE_BLOCKS_FORGET);
1257         } else {
1258                 ref--;
1259                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1260                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1261                         struct mb_cache_entry *ce;
1262
1263                         if (ea_block_cache) {
1264                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1265                                                         bh->b_blocknr);
1266                                 if (ce) {
1267                                         ce->e_reusable = 1;
1268                                         mb_cache_entry_put(ea_block_cache, ce);
1269                                 }
1270                         }
1271                 }
1272
1273                 ext4_xattr_block_csum_set(inode, bh);
1274                 /*
1275                  * Beware of this ugliness: Releasing of xattr block references
1276                  * from different inodes can race and so we have to protect
1277                  * from a race where someone else frees the block (and releases
1278                  * its journal_head) before we are done dirtying the buffer. In
1279                  * nojournal mode this race is harmless and we actually cannot
1280                  * call ext4_handle_dirty_metadata() with locked buffer as
1281                  * that function can call sync_dirty_buffer() so for that case
1282                  * we handle the dirtying after unlocking the buffer.
1283                  */
1284                 if (ext4_handle_valid(handle))
1285                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1286                 unlock_buffer(bh);
1287                 if (!ext4_handle_valid(handle))
1288                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1289                 if (IS_SYNC(inode))
1290                         ext4_handle_sync(handle);
1291                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1292                 ea_bdebug(bh, "refcount now=%d; releasing",
1293                           le32_to_cpu(BHDR(bh)->h_refcount));
1294         }
1295 out:
1296         ext4_std_error(inode->i_sb, error);
1297         return;
1298 }
1299
1300 /*
1301  * Find the available free space for EAs. This also returns the total number of
1302  * bytes used by EA entries.
1303  */
1304 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1305                                     size_t *min_offs, void *base, int *total)
1306 {
1307         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1308                 if (!last->e_value_inum && last->e_value_size) {
1309                         size_t offs = le16_to_cpu(last->e_value_offs);
1310                         if (offs < *min_offs)
1311                                 *min_offs = offs;
1312                 }
1313                 if (total)
1314                         *total += EXT4_XATTR_LEN(last->e_name_len);
1315         }
1316         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1317 }
1318
1319 /*
1320  * Write the value of the EA in an inode.
1321  */
1322 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1323                                   const void *buf, int bufsize)
1324 {
1325         struct buffer_head *bh = NULL;
1326         unsigned long block = 0;
1327         int blocksize = ea_inode->i_sb->s_blocksize;
1328         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1329         int csize, wsize = 0;
1330         int ret = 0;
1331         int retries = 0;
1332
1333 retry:
1334         while (ret >= 0 && ret < max_blocks) {
1335                 struct ext4_map_blocks map;
1336                 map.m_lblk = block += ret;
1337                 map.m_len = max_blocks -= ret;
1338
1339                 ret = ext4_map_blocks(handle, ea_inode, &map,
1340                                       EXT4_GET_BLOCKS_CREATE);
1341                 if (ret <= 0) {
1342                         ext4_mark_inode_dirty(handle, ea_inode);
1343                         if (ret == -ENOSPC &&
1344                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1345                                 ret = 0;
1346                                 goto retry;
1347                         }
1348                         break;
1349                 }
1350         }
1351
1352         if (ret < 0)
1353                 return ret;
1354
1355         block = 0;
1356         while (wsize < bufsize) {
1357                 if (bh != NULL)
1358                         brelse(bh);
1359                 csize = (bufsize - wsize) > blocksize ? blocksize :
1360                                                                 bufsize - wsize;
1361                 bh = ext4_getblk(handle, ea_inode, block, 0);
1362                 if (IS_ERR(bh))
1363                         return PTR_ERR(bh);
1364                 ret = ext4_journal_get_write_access(handle, bh);
1365                 if (ret)
1366                         goto out;
1367
1368                 memcpy(bh->b_data, buf, csize);
1369                 set_buffer_uptodate(bh);
1370                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1371
1372                 buf += csize;
1373                 wsize += csize;
1374                 block += 1;
1375         }
1376
1377         inode_lock(ea_inode);
1378         i_size_write(ea_inode, wsize);
1379         ext4_update_i_disksize(ea_inode, wsize);
1380         inode_unlock(ea_inode);
1381
1382         ext4_mark_inode_dirty(handle, ea_inode);
1383
1384 out:
1385         brelse(bh);
1386
1387         return ret;
1388 }
1389
1390 /*
1391  * Create an inode to store the value of a large EA.
1392  */
1393 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1394                                              struct inode *inode, u32 hash)
1395 {
1396         struct inode *ea_inode = NULL;
1397         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1398         int err;
1399
1400         /*
1401          * Let the next inode be the goal, so we try and allocate the EA inode
1402          * in the same group, or nearby one.
1403          */
1404         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1405                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1406                                   EXT4_EA_INODE_FL);
1407         if (!IS_ERR(ea_inode)) {
1408                 ea_inode->i_op = &ext4_file_inode_operations;
1409                 ea_inode->i_fop = &ext4_file_operations;
1410                 ext4_set_aops(ea_inode);
1411                 ext4_xattr_inode_set_class(ea_inode);
1412                 unlock_new_inode(ea_inode);
1413                 ext4_xattr_inode_set_ref(ea_inode, 1);
1414                 ext4_xattr_inode_set_hash(ea_inode, hash);
1415                 err = ext4_mark_inode_dirty(handle, ea_inode);
1416                 if (!err)
1417                         err = ext4_inode_attach_jinode(ea_inode);
1418                 if (err) {
1419                         iput(ea_inode);
1420                         return ERR_PTR(err);
1421                 }
1422
1423                 /*
1424                  * Xattr inodes are shared therefore quota charging is performed
1425                  * at a higher level.
1426                  */
1427                 dquot_free_inode(ea_inode);
1428                 dquot_drop(ea_inode);
1429                 inode_lock(ea_inode);
1430                 ea_inode->i_flags |= S_NOQUOTA;
1431                 inode_unlock(ea_inode);
1432         }
1433
1434         return ea_inode;
1435 }
1436
1437 static struct inode *
1438 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1439                             size_t value_len, u32 hash)
1440 {
1441         struct inode *ea_inode;
1442         struct mb_cache_entry *ce;
1443         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1444         void *ea_data;
1445
1446         if (!ea_inode_cache)
1447                 return NULL;
1448
1449         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1450         if (!ce)
1451                 return NULL;
1452
1453         ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
1454         if (!ea_data) {
1455                 mb_cache_entry_put(ea_inode_cache, ce);
1456                 return NULL;
1457         }
1458
1459         while (ce) {
1460                 ea_inode = ext4_iget(inode->i_sb, ce->e_value);
1461                 if (!IS_ERR(ea_inode) &&
1462                     !is_bad_inode(ea_inode) &&
1463                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1464                     i_size_read(ea_inode) == value_len &&
1465                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1466                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1467                                                     value_len) &&
1468                     !memcmp(value, ea_data, value_len)) {
1469                         mb_cache_entry_touch(ea_inode_cache, ce);
1470                         mb_cache_entry_put(ea_inode_cache, ce);
1471                         kvfree(ea_data);
1472                         return ea_inode;
1473                 }
1474
1475                 if (!IS_ERR(ea_inode))
1476                         iput(ea_inode);
1477                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1478         }
1479         kvfree(ea_data);
1480         return NULL;
1481 }
1482
1483 /*
1484  * Add value of the EA in an inode.
1485  */
1486 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1487                                           const void *value, size_t value_len,
1488                                           struct inode **ret_inode)
1489 {
1490         struct inode *ea_inode;
1491         u32 hash;
1492         int err;
1493
1494         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1495         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1496         if (ea_inode) {
1497                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1498                 if (err) {
1499                         iput(ea_inode);
1500                         return err;
1501                 }
1502
1503                 *ret_inode = ea_inode;
1504                 return 0;
1505         }
1506
1507         /* Create an inode for the EA value */
1508         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1509         if (IS_ERR(ea_inode))
1510                 return PTR_ERR(ea_inode);
1511
1512         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1513         if (err) {
1514                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1515                 iput(ea_inode);
1516                 return err;
1517         }
1518
1519         if (EA_INODE_CACHE(inode))
1520                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1521                                       ea_inode->i_ino, true /* reusable */);
1522
1523         *ret_inode = ea_inode;
1524         return 0;
1525 }
1526
1527 /*
1528  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1529  * feature is enabled.
1530  */
1531 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1532
1533 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1534                                 struct ext4_xattr_search *s,
1535                                 handle_t *handle, struct inode *inode,
1536                                 bool is_block)
1537 {
1538         struct ext4_xattr_entry *last;
1539         struct ext4_xattr_entry *here = s->here;
1540         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1541         int in_inode = i->in_inode;
1542         struct inode *old_ea_inode = NULL;
1543         struct inode *new_ea_inode = NULL;
1544         size_t old_size, new_size;
1545         int ret;
1546
1547         /* Space used by old and new values. */
1548         old_size = (!s->not_found && !here->e_value_inum) ?
1549                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1550         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1551
1552         /*
1553          * Optimization for the simple case when old and new values have the
1554          * same padded sizes. Not applicable if external inodes are involved.
1555          */
1556         if (new_size && new_size == old_size) {
1557                 size_t offs = le16_to_cpu(here->e_value_offs);
1558                 void *val = s->base + offs;
1559
1560                 here->e_value_size = cpu_to_le32(i->value_len);
1561                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1562                         memset(val, 0, new_size);
1563                 } else {
1564                         memcpy(val, i->value, i->value_len);
1565                         /* Clear padding bytes. */
1566                         memset(val + i->value_len, 0, new_size - i->value_len);
1567                 }
1568                 goto update_hash;
1569         }
1570
1571         /* Compute min_offs and last. */
1572         last = s->first;
1573         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1574                 if (!last->e_value_inum && last->e_value_size) {
1575                         size_t offs = le16_to_cpu(last->e_value_offs);
1576                         if (offs < min_offs)
1577                                 min_offs = offs;
1578                 }
1579         }
1580
1581         /* Check whether we have enough space. */
1582         if (i->value) {
1583                 size_t free;
1584
1585                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1586                 if (!s->not_found)
1587                         free += EXT4_XATTR_LEN(name_len) + old_size;
1588
1589                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1590                         ret = -ENOSPC;
1591                         goto out;
1592                 }
1593
1594                 /*
1595                  * If storing the value in an external inode is an option,
1596                  * reserve space for xattr entries/names in the external
1597                  * attribute block so that a long value does not occupy the
1598                  * whole space and prevent futher entries being added.
1599                  */
1600                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1601                     new_size && is_block &&
1602                     (min_offs + old_size - new_size) <
1603                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1604                         ret = -ENOSPC;
1605                         goto out;
1606                 }
1607         }
1608
1609         /*
1610          * Getting access to old and new ea inodes is subject to failures.
1611          * Finish that work before doing any modifications to the xattr data.
1612          */
1613         if (!s->not_found && here->e_value_inum) {
1614                 ret = ext4_xattr_inode_iget(inode,
1615                                             le32_to_cpu(here->e_value_inum),
1616                                             le32_to_cpu(here->e_hash),
1617                                             &old_ea_inode);
1618                 if (ret) {
1619                         old_ea_inode = NULL;
1620                         goto out;
1621                 }
1622         }
1623         if (i->value && in_inode) {
1624                 WARN_ON_ONCE(!i->value_len);
1625
1626                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1627                 if (ret)
1628                         goto out;
1629
1630                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1631                                                      i->value_len,
1632                                                      &new_ea_inode);
1633                 if (ret) {
1634                         new_ea_inode = NULL;
1635                         ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1636                         goto out;
1637                 }
1638         }
1639
1640         if (old_ea_inode) {
1641                 /* We are ready to release ref count on the old_ea_inode. */
1642                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1643                 if (ret) {
1644                         /* Release newly required ref count on new_ea_inode. */
1645                         if (new_ea_inode) {
1646                                 int err;
1647
1648                                 err = ext4_xattr_inode_dec_ref(handle,
1649                                                                new_ea_inode);
1650                                 if (err)
1651                                         ext4_warning_inode(new_ea_inode,
1652                                                   "dec ref new_ea_inode err=%d",
1653                                                   err);
1654                                 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1655                                                             i->value_len);
1656                         }
1657                         goto out;
1658                 }
1659
1660                 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1661                                             le32_to_cpu(here->e_value_size));
1662         }
1663
1664         /* No failures allowed past this point. */
1665
1666         if (!s->not_found && here->e_value_offs) {
1667                 /* Remove the old value. */
1668                 void *first_val = s->base + min_offs;
1669                 size_t offs = le16_to_cpu(here->e_value_offs);
1670                 void *val = s->base + offs;
1671
1672                 memmove(first_val + old_size, first_val, val - first_val);
1673                 memset(first_val, 0, old_size);
1674                 min_offs += old_size;
1675
1676                 /* Adjust all value offsets. */
1677                 last = s->first;
1678                 while (!IS_LAST_ENTRY(last)) {
1679                         size_t o = le16_to_cpu(last->e_value_offs);
1680
1681                         if (!last->e_value_inum &&
1682                             last->e_value_size && o < offs)
1683                                 last->e_value_offs = cpu_to_le16(o + old_size);
1684                         last = EXT4_XATTR_NEXT(last);
1685                 }
1686         }
1687
1688         if (!i->value) {
1689                 /* Remove old name. */
1690                 size_t size = EXT4_XATTR_LEN(name_len);
1691
1692                 last = ENTRY((void *)last - size);
1693                 memmove(here, (void *)here + size,
1694                         (void *)last - (void *)here + sizeof(__u32));
1695                 memset(last, 0, size);
1696         } else if (s->not_found) {
1697                 /* Insert new name. */
1698                 size_t size = EXT4_XATTR_LEN(name_len);
1699                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1700
1701                 memmove((void *)here + size, here, rest);
1702                 memset(here, 0, size);
1703                 here->e_name_index = i->name_index;
1704                 here->e_name_len = name_len;
1705                 memcpy(here->e_name, i->name, name_len);
1706         } else {
1707                 /* This is an update, reset value info. */
1708                 here->e_value_inum = 0;
1709                 here->e_value_offs = 0;
1710                 here->e_value_size = 0;
1711         }
1712
1713         if (i->value) {
1714                 /* Insert new value. */
1715                 if (in_inode) {
1716                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1717                 } else if (i->value_len) {
1718                         void *val = s->base + min_offs - new_size;
1719
1720                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1721                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1722                                 memset(val, 0, new_size);
1723                         } else {
1724                                 memcpy(val, i->value, i->value_len);
1725                                 /* Clear padding bytes. */
1726                                 memset(val + i->value_len, 0,
1727                                        new_size - i->value_len);
1728                         }
1729                 }
1730                 here->e_value_size = cpu_to_le32(i->value_len);
1731         }
1732
1733 update_hash:
1734         if (i->value) {
1735                 __le32 hash = 0;
1736
1737                 /* Entry hash calculation. */
1738                 if (in_inode) {
1739                         __le32 crc32c_hash;
1740
1741                         /*
1742                          * Feed crc32c hash instead of the raw value for entry
1743                          * hash calculation. This is to avoid walking
1744                          * potentially long value buffer again.
1745                          */
1746                         crc32c_hash = cpu_to_le32(
1747                                        ext4_xattr_inode_get_hash(new_ea_inode));
1748                         hash = ext4_xattr_hash_entry(here->e_name,
1749                                                      here->e_name_len,
1750                                                      &crc32c_hash, 1);
1751                 } else if (is_block) {
1752                         __le32 *value = s->base + le16_to_cpu(
1753                                                         here->e_value_offs);
1754
1755                         hash = ext4_xattr_hash_entry(here->e_name,
1756                                                      here->e_name_len, value,
1757                                                      new_size >> 2);
1758                 }
1759                 here->e_hash = hash;
1760         }
1761
1762         if (is_block)
1763                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1764
1765         ret = 0;
1766 out:
1767         iput(old_ea_inode);
1768         iput(new_ea_inode);
1769         return ret;
1770 }
1771
1772 struct ext4_xattr_block_find {
1773         struct ext4_xattr_search s;
1774         struct buffer_head *bh;
1775 };
1776
1777 static int
1778 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1779                       struct ext4_xattr_block_find *bs)
1780 {
1781         struct super_block *sb = inode->i_sb;
1782         int error;
1783
1784         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1785                   i->name_index, i->name, i->value, (long)i->value_len);
1786
1787         if (EXT4_I(inode)->i_file_acl) {
1788                 /* The inode already has an extended attribute block. */
1789                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
1790                 error = -EIO;
1791                 if (!bs->bh)
1792                         goto cleanup;
1793                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1794                         atomic_read(&(bs->bh->b_count)),
1795                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1796                 if (ext4_xattr_check_block(inode, bs->bh)) {
1797                         EXT4_ERROR_INODE(inode, "bad block %llu",
1798                                          EXT4_I(inode)->i_file_acl);
1799                         error = -EFSCORRUPTED;
1800                         goto cleanup;
1801                 }
1802                 /* Find the named attribute. */
1803                 bs->s.base = BHDR(bs->bh);
1804                 bs->s.first = BFIRST(bs->bh);
1805                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1806                 bs->s.here = bs->s.first;
1807                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
1808                                               i->name, 1);
1809                 if (error && error != -ENODATA)
1810                         goto cleanup;
1811                 bs->s.not_found = error;
1812         }
1813         error = 0;
1814
1815 cleanup:
1816         return error;
1817 }
1818
1819 static int
1820 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1821                      struct ext4_xattr_info *i,
1822                      struct ext4_xattr_block_find *bs)
1823 {
1824         struct super_block *sb = inode->i_sb;
1825         struct buffer_head *new_bh = NULL;
1826         struct ext4_xattr_search s_copy = bs->s;
1827         struct ext4_xattr_search *s = &s_copy;
1828         struct mb_cache_entry *ce = NULL;
1829         int error = 0;
1830         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1831         struct inode *ea_inode = NULL, *tmp_inode;
1832         size_t old_ea_inode_quota = 0;
1833         unsigned int ea_ino;
1834
1835
1836 #define header(x) ((struct ext4_xattr_header *)(x))
1837
1838         if (s->base) {
1839                 BUFFER_TRACE(bs->bh, "get_write_access");
1840                 error = ext4_journal_get_write_access(handle, bs->bh);
1841                 if (error)
1842                         goto cleanup;
1843                 lock_buffer(bs->bh);
1844
1845                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1846                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1847
1848                         /*
1849                          * This must happen under buffer lock for
1850                          * ext4_xattr_block_set() to reliably detect modified
1851                          * block
1852                          */
1853                         if (ea_block_cache)
1854                                 mb_cache_entry_delete(ea_block_cache, hash,
1855                                                       bs->bh->b_blocknr);
1856                         ea_bdebug(bs->bh, "modifying in-place");
1857                         error = ext4_xattr_set_entry(i, s, handle, inode,
1858                                                      true /* is_block */);
1859                         ext4_xattr_block_csum_set(inode, bs->bh);
1860                         unlock_buffer(bs->bh);
1861                         if (error == -EFSCORRUPTED)
1862                                 goto bad_block;
1863                         if (!error)
1864                                 error = ext4_handle_dirty_metadata(handle,
1865                                                                    inode,
1866                                                                    bs->bh);
1867                         if (error)
1868                                 goto cleanup;
1869                         goto inserted;
1870                 } else {
1871                         int offset = (char *)s->here - bs->bh->b_data;
1872
1873                         unlock_buffer(bs->bh);
1874                         ea_bdebug(bs->bh, "cloning");
1875                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1876                         error = -ENOMEM;
1877                         if (s->base == NULL)
1878                                 goto cleanup;
1879                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1880                         s->first = ENTRY(header(s->base)+1);
1881                         header(s->base)->h_refcount = cpu_to_le32(1);
1882                         s->here = ENTRY(s->base + offset);
1883                         s->end = s->base + bs->bh->b_size;
1884
1885                         /*
1886                          * If existing entry points to an xattr inode, we need
1887                          * to prevent ext4_xattr_set_entry() from decrementing
1888                          * ref count on it because the reference belongs to the
1889                          * original block. In this case, make the entry look
1890                          * like it has an empty value.
1891                          */
1892                         if (!s->not_found && s->here->e_value_inum) {
1893                                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1894                                 error = ext4_xattr_inode_iget(inode, ea_ino,
1895                                               le32_to_cpu(s->here->e_hash),
1896                                               &tmp_inode);
1897                                 if (error)
1898                                         goto cleanup;
1899
1900                                 if (!ext4_test_inode_state(tmp_inode,
1901                                                 EXT4_STATE_LUSTRE_EA_INODE)) {
1902                                         /*
1903                                          * Defer quota free call for previous
1904                                          * inode until success is guaranteed.
1905                                          */
1906                                         old_ea_inode_quota = le32_to_cpu(
1907                                                         s->here->e_value_size);
1908                                 }
1909                                 iput(tmp_inode);
1910
1911                                 s->here->e_value_inum = 0;
1912                                 s->here->e_value_size = 0;
1913                         }
1914                 }
1915         } else {
1916                 /* Allocate a buffer where we construct the new block. */
1917                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1918                 /* assert(header == s->base) */
1919                 error = -ENOMEM;
1920                 if (s->base == NULL)
1921                         goto cleanup;
1922                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1923                 header(s->base)->h_blocks = cpu_to_le32(1);
1924                 header(s->base)->h_refcount = cpu_to_le32(1);
1925                 s->first = ENTRY(header(s->base)+1);
1926                 s->here = ENTRY(header(s->base)+1);
1927                 s->end = s->base + sb->s_blocksize;
1928         }
1929
1930         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1931         if (error == -EFSCORRUPTED)
1932                 goto bad_block;
1933         if (error)
1934                 goto cleanup;
1935
1936         if (i->value && s->here->e_value_inum) {
1937                 /*
1938                  * A ref count on ea_inode has been taken as part of the call to
1939                  * ext4_xattr_set_entry() above. We would like to drop this
1940                  * extra ref but we have to wait until the xattr block is
1941                  * initialized and has its own ref count on the ea_inode.
1942                  */
1943                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1944                 error = ext4_xattr_inode_iget(inode, ea_ino,
1945                                               le32_to_cpu(s->here->e_hash),
1946                                               &ea_inode);
1947                 if (error) {
1948                         ea_inode = NULL;
1949                         goto cleanup;
1950                 }
1951         }
1952
1953 inserted:
1954         if (!IS_LAST_ENTRY(s->first)) {
1955                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1956                                                      &ce);
1957                 if (new_bh) {
1958                         /* We found an identical block in the cache. */
1959                         if (new_bh == bs->bh)
1960                                 ea_bdebug(new_bh, "keeping");
1961                         else {
1962                                 u32 ref;
1963
1964                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
1965
1966                                 /* The old block is released after updating
1967                                    the inode. */
1968                                 error = dquot_alloc_block(inode,
1969                                                 EXT4_C2B(EXT4_SB(sb), 1));
1970                                 if (error)
1971                                         goto cleanup;
1972                                 BUFFER_TRACE(new_bh, "get_write_access");
1973                                 error = ext4_journal_get_write_access(handle,
1974                                                                       new_bh);
1975                                 if (error)
1976                                         goto cleanup_dquot;
1977                                 lock_buffer(new_bh);
1978                                 /*
1979                                  * We have to be careful about races with
1980                                  * freeing, rehashing or adding references to
1981                                  * xattr block. Once we hold buffer lock xattr
1982                                  * block's state is stable so we can check
1983                                  * whether the block got freed / rehashed or
1984                                  * not.  Since we unhash mbcache entry under
1985                                  * buffer lock when freeing / rehashing xattr
1986                                  * block, checking whether entry is still
1987                                  * hashed is reliable. Same rules hold for
1988                                  * e_reusable handling.
1989                                  */
1990                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
1991                                     !ce->e_reusable) {
1992                                         /*
1993                                          * Undo everything and check mbcache
1994                                          * again.
1995                                          */
1996                                         unlock_buffer(new_bh);
1997                                         dquot_free_block(inode,
1998                                                          EXT4_C2B(EXT4_SB(sb),
1999                                                                   1));
2000                                         brelse(new_bh);
2001                                         mb_cache_entry_put(ea_block_cache, ce);
2002                                         ce = NULL;
2003                                         new_bh = NULL;
2004                                         goto inserted;
2005                                 }
2006                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2007                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2008                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2009                                         ce->e_reusable = 0;
2010                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
2011                                           ref);
2012                                 ext4_xattr_block_csum_set(inode, new_bh);
2013                                 unlock_buffer(new_bh);
2014                                 error = ext4_handle_dirty_metadata(handle,
2015                                                                    inode,
2016                                                                    new_bh);
2017                                 if (error)
2018                                         goto cleanup_dquot;
2019                         }
2020                         mb_cache_entry_touch(ea_block_cache, ce);
2021                         mb_cache_entry_put(ea_block_cache, ce);
2022                         ce = NULL;
2023                 } else if (bs->bh && s->base == bs->bh->b_data) {
2024                         /* We were modifying this block in-place. */
2025                         ea_bdebug(bs->bh, "keeping this block");
2026                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2027                         new_bh = bs->bh;
2028                         get_bh(new_bh);
2029                 } else {
2030                         /* We need to allocate a new block */
2031                         ext4_fsblk_t goal, block;
2032
2033                         WARN_ON_ONCE(dquot_initialize_needed(inode));
2034
2035                         goal = ext4_group_first_block_no(sb,
2036                                                 EXT4_I(inode)->i_block_group);
2037
2038                         /* non-extent files can't have physical blocks past 2^32 */
2039                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2040                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2041
2042                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2043                                                      NULL, &error);
2044                         if (error)
2045                                 goto cleanup;
2046
2047                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2048                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2049
2050                         ea_idebug(inode, "creating block %llu",
2051                                   (unsigned long long)block);
2052
2053                         new_bh = sb_getblk(sb, block);
2054                         if (unlikely(!new_bh)) {
2055                                 error = -ENOMEM;
2056 getblk_failed:
2057                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2058                                                  EXT4_FREE_BLOCKS_METADATA);
2059                                 goto cleanup;
2060                         }
2061                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2062                                                       ENTRY(header(s->base)+1));
2063                         if (error)
2064                                 goto getblk_failed;
2065                         if (ea_inode) {
2066                                 /* Drop the extra ref on ea_inode. */
2067                                 error = ext4_xattr_inode_dec_ref(handle,
2068                                                                  ea_inode);
2069                                 if (error)
2070                                         ext4_warning_inode(ea_inode,
2071                                                            "dec ref error=%d",
2072                                                            error);
2073                                 iput(ea_inode);
2074                                 ea_inode = NULL;
2075                         }
2076
2077                         lock_buffer(new_bh);
2078                         error = ext4_journal_get_create_access(handle, new_bh);
2079                         if (error) {
2080                                 unlock_buffer(new_bh);
2081                                 error = -EIO;
2082                                 goto getblk_failed;
2083                         }
2084                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2085                         ext4_xattr_block_csum_set(inode, new_bh);
2086                         set_buffer_uptodate(new_bh);
2087                         unlock_buffer(new_bh);
2088                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2089                         error = ext4_handle_dirty_metadata(handle, inode,
2090                                                            new_bh);
2091                         if (error)
2092                                 goto cleanup;
2093                 }
2094         }
2095
2096         if (old_ea_inode_quota)
2097                 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2098
2099         /* Update the inode. */
2100         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2101
2102         /* Drop the previous xattr block. */
2103         if (bs->bh && bs->bh != new_bh) {
2104                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2105
2106                 ext4_xattr_release_block(handle, inode, bs->bh,
2107                                          &ea_inode_array,
2108                                          0 /* extra_credits */);
2109                 ext4_xattr_inode_array_free(ea_inode_array);
2110         }
2111         error = 0;
2112
2113 cleanup:
2114         if (ea_inode) {
2115                 int error2;
2116
2117                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2118                 if (error2)
2119                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2120                                            error2);
2121
2122                 /* If there was an error, revert the quota charge. */
2123                 if (error)
2124                         ext4_xattr_inode_free_quota(inode, ea_inode,
2125                                                     i_size_read(ea_inode));
2126                 iput(ea_inode);
2127         }
2128         if (ce)
2129                 mb_cache_entry_put(ea_block_cache, ce);
2130         brelse(new_bh);
2131         if (!(bs->bh && s->base == bs->bh->b_data))
2132                 kfree(s->base);
2133
2134         return error;
2135
2136 cleanup_dquot:
2137         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2138         goto cleanup;
2139
2140 bad_block:
2141         EXT4_ERROR_INODE(inode, "bad block %llu",
2142                          EXT4_I(inode)->i_file_acl);
2143         goto cleanup;
2144
2145 #undef header
2146 }
2147
2148 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2149                           struct ext4_xattr_ibody_find *is)
2150 {
2151         struct ext4_xattr_ibody_header *header;
2152         struct ext4_inode *raw_inode;
2153         int error;
2154
2155         if (EXT4_I(inode)->i_extra_isize == 0)
2156                 return 0;
2157         raw_inode = ext4_raw_inode(&is->iloc);
2158         header = IHDR(inode, raw_inode);
2159         is->s.base = is->s.first = IFIRST(header);
2160         is->s.here = is->s.first;
2161         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2162         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2163                 error = xattr_check_inode(inode, header, is->s.end);
2164                 if (error)
2165                         return error;
2166                 /* Find the named attribute. */
2167                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
2168                                               i->name, 0);
2169                 if (error && error != -ENODATA)
2170                         return error;
2171                 is->s.not_found = error;
2172         }
2173         return 0;
2174 }
2175
2176 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2177                                 struct ext4_xattr_info *i,
2178                                 struct ext4_xattr_ibody_find *is)
2179 {
2180         struct ext4_xattr_ibody_header *header;
2181         struct ext4_xattr_search *s = &is->s;
2182         int error;
2183
2184         if (EXT4_I(inode)->i_extra_isize == 0)
2185                 return -ENOSPC;
2186         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2187         if (error) {
2188                 if (error == -ENOSPC &&
2189                     ext4_has_inline_data(inode)) {
2190                         error = ext4_try_to_evict_inline_data(handle, inode,
2191                                         EXT4_XATTR_LEN(strlen(i->name) +
2192                                         EXT4_XATTR_SIZE(i->value_len)));
2193                         if (error)
2194                                 return error;
2195                         error = ext4_xattr_ibody_find(inode, i, is);
2196                         if (error)
2197                                 return error;
2198                         error = ext4_xattr_set_entry(i, s, handle, inode,
2199                                                      false /* is_block */);
2200                 }
2201                 if (error)
2202                         return error;
2203         }
2204         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2205         if (!IS_LAST_ENTRY(s->first)) {
2206                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2207                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2208         } else {
2209                 header->h_magic = cpu_to_le32(0);
2210                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2211         }
2212         return 0;
2213 }
2214
2215 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2216                                 struct ext4_xattr_info *i,
2217                                 struct ext4_xattr_ibody_find *is)
2218 {
2219         struct ext4_xattr_ibody_header *header;
2220         struct ext4_xattr_search *s = &is->s;
2221         int error;
2222
2223         if (EXT4_I(inode)->i_extra_isize == 0)
2224                 return -ENOSPC;
2225         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2226         if (error)
2227                 return error;
2228         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2229         if (!IS_LAST_ENTRY(s->first)) {
2230                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2231                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2232         } else {
2233                 header->h_magic = cpu_to_le32(0);
2234                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2235         }
2236         return 0;
2237 }
2238
2239 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2240                                  struct ext4_xattr_info *i)
2241 {
2242         void *value;
2243
2244         /* When e_value_inum is set the value is stored externally. */
2245         if (s->here->e_value_inum)
2246                 return 0;
2247         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2248                 return 0;
2249         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2250         return !memcmp(value, i->value, i->value_len);
2251 }
2252
2253 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2254 {
2255         struct buffer_head *bh;
2256         int error;
2257
2258         if (!EXT4_I(inode)->i_file_acl)
2259                 return NULL;
2260         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2261         if (!bh)
2262                 return ERR_PTR(-EIO);
2263         error = ext4_xattr_check_block(inode, bh);
2264         if (error)
2265                 return ERR_PTR(error);
2266         return bh;
2267 }
2268
2269 /*
2270  * ext4_xattr_set_handle()
2271  *
2272  * Create, replace or remove an extended attribute for this inode.  Value
2273  * is NULL to remove an existing extended attribute, and non-NULL to
2274  * either replace an existing extended attribute, or create a new extended
2275  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2276  * specify that an extended attribute must exist and must not exist
2277  * previous to the call, respectively.
2278  *
2279  * Returns 0, or a negative error number on failure.
2280  */
2281 int
2282 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2283                       const char *name, const void *value, size_t value_len,
2284                       int flags)
2285 {
2286         struct ext4_xattr_info i = {
2287                 .name_index = name_index,
2288                 .name = name,
2289                 .value = value,
2290                 .value_len = value_len,
2291                 .in_inode = 0,
2292         };
2293         struct ext4_xattr_ibody_find is = {
2294                 .s = { .not_found = -ENODATA, },
2295         };
2296         struct ext4_xattr_block_find bs = {
2297                 .s = { .not_found = -ENODATA, },
2298         };
2299         int no_expand;
2300         int error;
2301
2302         if (!name)
2303                 return -EINVAL;
2304         if (strlen(name) > 255)
2305                 return -ERANGE;
2306
2307         ext4_write_lock_xattr(inode, &no_expand);
2308
2309         /* Check journal credits under write lock. */
2310         if (ext4_handle_valid(handle)) {
2311                 struct buffer_head *bh;
2312                 int credits;
2313
2314                 bh = ext4_xattr_get_block(inode);
2315                 if (IS_ERR(bh)) {
2316                         error = PTR_ERR(bh);
2317                         goto cleanup;
2318                 }
2319
2320                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2321                                                    value_len,
2322                                                    flags & XATTR_CREATE);
2323                 brelse(bh);
2324
2325                 if (!ext4_handle_has_enough_credits(handle, credits)) {
2326                         error = -ENOSPC;
2327                         goto cleanup;
2328                 }
2329         }
2330
2331         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2332         if (error)
2333                 goto cleanup;
2334
2335         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2336                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2337                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2338                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2339         }
2340
2341         error = ext4_xattr_ibody_find(inode, &i, &is);
2342         if (error)
2343                 goto cleanup;
2344         if (is.s.not_found)
2345                 error = ext4_xattr_block_find(inode, &i, &bs);
2346         if (error)
2347                 goto cleanup;
2348         if (is.s.not_found && bs.s.not_found) {
2349                 error = -ENODATA;
2350                 if (flags & XATTR_REPLACE)
2351                         goto cleanup;
2352                 error = 0;
2353                 if (!value)
2354                         goto cleanup;
2355         } else {
2356                 error = -EEXIST;
2357                 if (flags & XATTR_CREATE)
2358                         goto cleanup;
2359         }
2360
2361         if (!value) {
2362                 if (!is.s.not_found)
2363                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2364                 else if (!bs.s.not_found)
2365                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2366         } else {
2367                 error = 0;
2368                 /* Xattr value did not change? Save us some work and bail out */
2369                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2370                         goto cleanup;
2371                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2372                         goto cleanup;
2373
2374                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2375                     (EXT4_XATTR_SIZE(i.value_len) >
2376                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2377                         i.in_inode = 1;
2378 retry_inode:
2379                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2380                 if (!error && !bs.s.not_found) {
2381                         i.value = NULL;
2382                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2383                 } else if (error == -ENOSPC) {
2384                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2385                                 error = ext4_xattr_block_find(inode, &i, &bs);
2386                                 if (error)
2387                                         goto cleanup;
2388                         }
2389                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2390                         if (!error && !is.s.not_found) {
2391                                 i.value = NULL;
2392                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2393                                                              &is);
2394                         } else if (error == -ENOSPC) {
2395                                 /*
2396                                  * Xattr does not fit in the block, store at
2397                                  * external inode if possible.
2398                                  */
2399                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2400                                     !i.in_inode) {
2401                                         i.in_inode = 1;
2402                                         goto retry_inode;
2403                                 }
2404                         }
2405                 }
2406         }
2407         if (!error) {
2408                 ext4_xattr_update_super_block(handle, inode->i_sb);
2409                 inode->i_ctime = current_time(inode);
2410                 if (!value)
2411                         no_expand = 0;
2412                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2413                 /*
2414                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2415                  * error != 0.
2416                  */
2417                 is.iloc.bh = NULL;
2418                 if (IS_SYNC(inode))
2419                         ext4_handle_sync(handle);
2420         }
2421
2422 cleanup:
2423         brelse(is.iloc.bh);
2424         brelse(bs.bh);
2425         ext4_write_unlock_xattr(inode, &no_expand);
2426         return error;
2427 }
2428
2429 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2430                            bool is_create, int *credits)
2431 {
2432         struct buffer_head *bh;
2433         int err;
2434
2435         *credits = 0;
2436
2437         if (!EXT4_SB(inode->i_sb)->s_journal)
2438                 return 0;
2439
2440         down_read(&EXT4_I(inode)->xattr_sem);
2441
2442         bh = ext4_xattr_get_block(inode);
2443         if (IS_ERR(bh)) {
2444                 err = PTR_ERR(bh);
2445         } else {
2446                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2447                                                     value_len, is_create);
2448                 brelse(bh);
2449                 err = 0;
2450         }
2451
2452         up_read(&EXT4_I(inode)->xattr_sem);
2453         return err;
2454 }
2455
2456 /*
2457  * ext4_xattr_set()
2458  *
2459  * Like ext4_xattr_set_handle, but start from an inode. This extended
2460  * attribute modification is a filesystem transaction by itself.
2461  *
2462  * Returns 0, or a negative error number on failure.
2463  */
2464 int
2465 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2466                const void *value, size_t value_len, int flags)
2467 {
2468         handle_t *handle;
2469         struct super_block *sb = inode->i_sb;
2470         int error, retries = 0;
2471         int credits;
2472
2473         error = dquot_initialize(inode);
2474         if (error)
2475                 return error;
2476
2477 retry:
2478         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2479                                        &credits);
2480         if (error)
2481                 return error;
2482
2483         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2484         if (IS_ERR(handle)) {
2485                 error = PTR_ERR(handle);
2486         } else {
2487                 int error2;
2488
2489                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2490                                               value, value_len, flags);
2491                 error2 = ext4_journal_stop(handle);
2492                 if (error == -ENOSPC &&
2493                     ext4_should_retry_alloc(sb, &retries))
2494                         goto retry;
2495                 if (error == 0)
2496                         error = error2;
2497         }
2498
2499         return error;
2500 }
2501
2502 /*
2503  * Shift the EA entries in the inode to create space for the increased
2504  * i_extra_isize.
2505  */
2506 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2507                                      int value_offs_shift, void *to,
2508                                      void *from, size_t n)
2509 {
2510         struct ext4_xattr_entry *last = entry;
2511         int new_offs;
2512
2513         /* We always shift xattr headers further thus offsets get lower */
2514         BUG_ON(value_offs_shift > 0);
2515
2516         /* Adjust the value offsets of the entries */
2517         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2518                 if (!last->e_value_inum && last->e_value_size) {
2519                         new_offs = le16_to_cpu(last->e_value_offs) +
2520                                                         value_offs_shift;
2521                         last->e_value_offs = cpu_to_le16(new_offs);
2522                 }
2523         }
2524         /* Shift the entries by n bytes */
2525         memmove(to, from, n);
2526 }
2527
2528 /*
2529  * Move xattr pointed to by 'entry' from inode into external xattr block
2530  */
2531 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2532                                     struct ext4_inode *raw_inode,
2533                                     struct ext4_xattr_entry *entry)
2534 {
2535         struct ext4_xattr_ibody_find *is = NULL;
2536         struct ext4_xattr_block_find *bs = NULL;
2537         char *buffer = NULL, *b_entry_name = NULL;
2538         size_t value_size = le32_to_cpu(entry->e_value_size);
2539         struct ext4_xattr_info i = {
2540                 .value = NULL,
2541                 .value_len = 0,
2542                 .name_index = entry->e_name_index,
2543                 .in_inode = !!entry->e_value_inum,
2544         };
2545         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2546         int error;
2547
2548         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2549         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2550         buffer = kmalloc(value_size, GFP_NOFS);
2551         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2552         if (!is || !bs || !buffer || !b_entry_name) {
2553                 error = -ENOMEM;
2554                 goto out;
2555         }
2556
2557         is->s.not_found = -ENODATA;
2558         bs->s.not_found = -ENODATA;
2559         is->iloc.bh = NULL;
2560         bs->bh = NULL;
2561
2562         /* Save the entry name and the entry value */
2563         if (entry->e_value_inum) {
2564                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2565                 if (error)
2566                         goto out;
2567         } else {
2568                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2569                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2570         }
2571
2572         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2573         b_entry_name[entry->e_name_len] = '\0';
2574         i.name = b_entry_name;
2575
2576         error = ext4_get_inode_loc(inode, &is->iloc);
2577         if (error)
2578                 goto out;
2579
2580         error = ext4_xattr_ibody_find(inode, &i, is);
2581         if (error)
2582                 goto out;
2583
2584         /* Remove the chosen entry from the inode */
2585         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2586         if (error)
2587                 goto out;
2588
2589         i.value = buffer;
2590         i.value_len = value_size;
2591         error = ext4_xattr_block_find(inode, &i, bs);
2592         if (error)
2593                 goto out;
2594
2595         /* Add entry which was removed from the inode into the block */
2596         error = ext4_xattr_block_set(handle, inode, &i, bs);
2597         if (error)
2598                 goto out;
2599         error = 0;
2600 out:
2601         kfree(b_entry_name);
2602         kfree(buffer);
2603         if (is)
2604                 brelse(is->iloc.bh);
2605         kfree(is);
2606         kfree(bs);
2607
2608         return error;
2609 }
2610
2611 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2612                                        struct ext4_inode *raw_inode,
2613                                        int isize_diff, size_t ifree,
2614                                        size_t bfree, int *total_ino)
2615 {
2616         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2617         struct ext4_xattr_entry *small_entry;
2618         struct ext4_xattr_entry *entry;
2619         struct ext4_xattr_entry *last;
2620         unsigned int entry_size;        /* EA entry size */
2621         unsigned int total_size;        /* EA entry size + value size */
2622         unsigned int min_total_size;
2623         int error;
2624
2625         while (isize_diff > ifree) {
2626                 entry = NULL;
2627                 small_entry = NULL;
2628                 min_total_size = ~0U;
2629                 last = IFIRST(header);
2630                 /* Find the entry best suited to be pushed into EA block */
2631                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2632                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2633                         if (!last->e_value_inum)
2634                                 total_size += EXT4_XATTR_SIZE(
2635                                                le32_to_cpu(last->e_value_size));
2636                         if (total_size <= bfree &&
2637                             total_size < min_total_size) {
2638                                 if (total_size + ifree < isize_diff) {
2639                                         small_entry = last;
2640                                 } else {
2641                                         entry = last;
2642                                         min_total_size = total_size;
2643                                 }
2644                         }
2645                 }
2646
2647                 if (entry == NULL) {
2648                         if (small_entry == NULL)
2649                                 return -ENOSPC;
2650                         entry = small_entry;
2651                 }
2652
2653                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2654                 total_size = entry_size;
2655                 if (!entry->e_value_inum)
2656                         total_size += EXT4_XATTR_SIZE(
2657                                               le32_to_cpu(entry->e_value_size));
2658                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2659                                                  entry);
2660                 if (error)
2661                         return error;
2662
2663                 *total_ino -= entry_size;
2664                 ifree += total_size;
2665                 bfree -= total_size;
2666         }
2667
2668         return 0;
2669 }
2670
2671 /*
2672  * Expand an inode by new_extra_isize bytes when EAs are present.
2673  * Returns 0 on success or negative error number on failure.
2674  */
2675 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2676                                struct ext4_inode *raw_inode, handle_t *handle)
2677 {
2678         struct ext4_xattr_ibody_header *header;
2679         struct buffer_head *bh;
2680         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2681         static unsigned int mnt_count;
2682         size_t min_offs;
2683         size_t ifree, bfree;
2684         int total_ino;
2685         void *base, *end;
2686         int error = 0, tried_min_extra_isize = 0;
2687         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2688         int isize_diff; /* How much do we need to grow i_extra_isize */
2689
2690 retry:
2691         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2692         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2693                 return 0;
2694
2695         header = IHDR(inode, raw_inode);
2696
2697         /*
2698          * Check if enough free space is available in the inode to shift the
2699          * entries ahead by new_extra_isize.
2700          */
2701
2702         base = IFIRST(header);
2703         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2704         min_offs = end - base;
2705         total_ino = sizeof(struct ext4_xattr_ibody_header);
2706
2707         error = xattr_check_inode(inode, header, end);
2708         if (error)
2709                 goto cleanup;
2710
2711         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2712         if (ifree >= isize_diff)
2713                 goto shift;
2714
2715         /*
2716          * Enough free space isn't available in the inode, check if
2717          * EA block can hold new_extra_isize bytes.
2718          */
2719         if (EXT4_I(inode)->i_file_acl) {
2720                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2721                 error = -EIO;
2722                 if (!bh)
2723                         goto cleanup;
2724                 if (ext4_xattr_check_block(inode, bh)) {
2725                         EXT4_ERROR_INODE(inode, "bad block %llu",
2726                                          EXT4_I(inode)->i_file_acl);
2727                         error = -EFSCORRUPTED;
2728                         brelse(bh);
2729                         goto cleanup;
2730                 }
2731                 base = BHDR(bh);
2732                 end = bh->b_data + bh->b_size;
2733                 min_offs = end - base;
2734                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2735                                               NULL);
2736                 brelse(bh);
2737                 if (bfree + ifree < isize_diff) {
2738                         if (!tried_min_extra_isize && s_min_extra_isize) {
2739                                 tried_min_extra_isize++;
2740                                 new_extra_isize = s_min_extra_isize;
2741                                 goto retry;
2742                         }
2743                         error = -ENOSPC;
2744                         goto cleanup;
2745                 }
2746         } else {
2747                 bfree = inode->i_sb->s_blocksize;
2748         }
2749
2750         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2751                                             isize_diff, ifree, bfree,
2752                                             &total_ino);
2753         if (error) {
2754                 if (error == -ENOSPC && !tried_min_extra_isize &&
2755                     s_min_extra_isize) {
2756                         tried_min_extra_isize++;
2757                         new_extra_isize = s_min_extra_isize;
2758                         goto retry;
2759                 }
2760                 goto cleanup;
2761         }
2762 shift:
2763         /* Adjust the offsets and shift the remaining entries ahead */
2764         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2765                         - new_extra_isize, (void *)raw_inode +
2766                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2767                         (void *)header, total_ino);
2768         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2769
2770 cleanup:
2771         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2772                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2773                              inode->i_ino);
2774                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2775         }
2776         return error;
2777 }
2778
2779 #define EIA_INCR 16 /* must be 2^n */
2780 #define EIA_MASK (EIA_INCR - 1)
2781
2782 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2783  * If @ea_inode_array is new or full it will be grown and the old
2784  * contents copied over.
2785  */
2786 static int
2787 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2788                         struct inode *inode)
2789 {
2790         if (*ea_inode_array == NULL) {
2791                 /*
2792                  * Start with 15 inodes, so it fits into a power-of-two size.
2793                  * If *ea_inode_array is NULL, this is essentially offsetof()
2794                  */
2795                 (*ea_inode_array) =
2796                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2797                                          inodes[EIA_MASK]),
2798                                 GFP_NOFS);
2799                 if (*ea_inode_array == NULL)
2800                         return -ENOMEM;
2801                 (*ea_inode_array)->count = 0;
2802         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2803                 /* expand the array once all 15 + n * 16 slots are full */
2804                 struct ext4_xattr_inode_array *new_array = NULL;
2805                 int count = (*ea_inode_array)->count;
2806
2807                 /* if new_array is NULL, this is essentially offsetof() */
2808                 new_array = kmalloc(
2809                                 offsetof(struct ext4_xattr_inode_array,
2810                                          inodes[count + EIA_INCR]),
2811                                 GFP_NOFS);
2812                 if (new_array == NULL)
2813                         return -ENOMEM;
2814                 memcpy(new_array, *ea_inode_array,
2815                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2816                 kfree(*ea_inode_array);
2817                 *ea_inode_array = new_array;
2818         }
2819         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2820         return 0;
2821 }
2822
2823 /*
2824  * ext4_xattr_delete_inode()
2825  *
2826  * Free extended attribute resources associated with this inode. Traverse
2827  * all entries and decrement reference on any xattr inodes associated with this
2828  * inode. This is called immediately before an inode is freed. We have exclusive
2829  * access to the inode. If an orphan inode is deleted it will also release its
2830  * references on xattr block and xattr inodes.
2831  */
2832 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2833                             struct ext4_xattr_inode_array **ea_inode_array,
2834                             int extra_credits)
2835 {
2836         struct buffer_head *bh = NULL;
2837         struct ext4_xattr_ibody_header *header;
2838         struct ext4_iloc iloc = { .bh = NULL };
2839         struct ext4_xattr_entry *entry;
2840         struct inode *ea_inode;
2841         int error;
2842
2843         error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
2844                                           NULL /* bh */,
2845                                           false /* dirty */,
2846                                           false /* block_csum */);
2847         if (error) {
2848                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2849                 goto cleanup;
2850         }
2851
2852         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2853             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2854
2855                 error = ext4_get_inode_loc(inode, &iloc);
2856                 if (error) {
2857                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2858                         goto cleanup;
2859                 }
2860
2861                 error = ext4_journal_get_write_access(handle, iloc.bh);
2862                 if (error) {
2863                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2864                                          error);
2865                         goto cleanup;
2866                 }
2867
2868                 header = IHDR(inode, ext4_raw_inode(&iloc));
2869                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2870                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2871                                                      IFIRST(header),
2872                                                      false /* block_csum */,
2873                                                      ea_inode_array,
2874                                                      extra_credits,
2875                                                      false /* skip_quota */);
2876         }
2877
2878         if (EXT4_I(inode)->i_file_acl) {
2879                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2880                 if (!bh) {
2881                         EXT4_ERROR_INODE(inode, "block %llu read error",
2882                                          EXT4_I(inode)->i_file_acl);
2883                         error = -EIO;
2884                         goto cleanup;
2885                 }
2886                 error = ext4_xattr_check_block(inode, bh);
2887                 if (error) {
2888                         EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
2889                                          EXT4_I(inode)->i_file_acl, error);
2890                         goto cleanup;
2891                 }
2892
2893                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2894                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2895                              entry = EXT4_XATTR_NEXT(entry)) {
2896                                 if (!entry->e_value_inum)
2897                                         continue;
2898                                 error = ext4_xattr_inode_iget(inode,
2899                                               le32_to_cpu(entry->e_value_inum),
2900                                               le32_to_cpu(entry->e_hash),
2901                                               &ea_inode);
2902                                 if (error)
2903                                         continue;
2904                                 ext4_xattr_inode_free_quota(inode, ea_inode,
2905                                               le32_to_cpu(entry->e_value_size));
2906                                 iput(ea_inode);
2907                         }
2908
2909                 }
2910
2911                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2912                                          extra_credits);
2913                 /*
2914                  * Update i_file_acl value in the same transaction that releases
2915                  * block.
2916                  */
2917                 EXT4_I(inode)->i_file_acl = 0;
2918                 error = ext4_mark_inode_dirty(handle, inode);
2919                 if (error) {
2920                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2921                                          error);
2922                         goto cleanup;
2923                 }
2924         }
2925         error = 0;
2926 cleanup:
2927         brelse(iloc.bh);
2928         brelse(bh);
2929         return error;
2930 }
2931
2932 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2933 {
2934         int idx;
2935
2936         if (ea_inode_array == NULL)
2937                 return;
2938
2939         for (idx = 0; idx < ea_inode_array->count; ++idx)
2940                 iput(ea_inode_array->inodes[idx]);
2941         kfree(ea_inode_array);
2942 }
2943
2944 /*
2945  * ext4_xattr_block_cache_insert()
2946  *
2947  * Create a new entry in the extended attribute block cache, and insert
2948  * it unless such an entry is already in the cache.
2949  *
2950  * Returns 0, or a negative error number on failure.
2951  */
2952 static void
2953 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2954                               struct buffer_head *bh)
2955 {
2956         struct ext4_xattr_header *header = BHDR(bh);
2957         __u32 hash = le32_to_cpu(header->h_hash);
2958         int reusable = le32_to_cpu(header->h_refcount) <
2959                        EXT4_XATTR_REFCOUNT_MAX;
2960         int error;
2961
2962         if (!ea_block_cache)
2963                 return;
2964         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2965                                       bh->b_blocknr, reusable);
2966         if (error) {
2967                 if (error == -EBUSY)
2968                         ea_bdebug(bh, "already in cache");
2969         } else
2970                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2971 }
2972
2973 /*
2974  * ext4_xattr_cmp()
2975  *
2976  * Compare two extended attribute blocks for equality.
2977  *
2978  * Returns 0 if the blocks are equal, 1 if they differ, and
2979  * a negative error number on errors.
2980  */
2981 static int
2982 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2983                struct ext4_xattr_header *header2)
2984 {
2985         struct ext4_xattr_entry *entry1, *entry2;
2986
2987         entry1 = ENTRY(header1+1);
2988         entry2 = ENTRY(header2+1);
2989         while (!IS_LAST_ENTRY(entry1)) {
2990                 if (IS_LAST_ENTRY(entry2))
2991                         return 1;
2992                 if (entry1->e_hash != entry2->e_hash ||
2993                     entry1->e_name_index != entry2->e_name_index ||
2994                     entry1->e_name_len != entry2->e_name_len ||
2995                     entry1->e_value_size != entry2->e_value_size ||
2996                     entry1->e_value_inum != entry2->e_value_inum ||
2997                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2998                         return 1;
2999                 if (!entry1->e_value_inum &&
3000                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3001                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3002                            le32_to_cpu(entry1->e_value_size)))
3003                         return 1;
3004
3005                 entry1 = EXT4_XATTR_NEXT(entry1);
3006                 entry2 = EXT4_XATTR_NEXT(entry2);
3007         }
3008         if (!IS_LAST_ENTRY(entry2))
3009                 return 1;
3010         return 0;
3011 }
3012
3013 /*
3014  * ext4_xattr_block_cache_find()
3015  *
3016  * Find an identical extended attribute block.
3017  *
3018  * Returns a pointer to the block found, or NULL if such a block was
3019  * not found or an error occurred.
3020  */
3021 static struct buffer_head *
3022 ext4_xattr_block_cache_find(struct inode *inode,
3023                             struct ext4_xattr_header *header,
3024                             struct mb_cache_entry **pce)
3025 {
3026         __u32 hash = le32_to_cpu(header->h_hash);
3027         struct mb_cache_entry *ce;
3028         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3029
3030         if (!ea_block_cache)
3031                 return NULL;
3032         if (!header->h_hash)
3033                 return NULL;  /* never share */
3034         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3035         ce = mb_cache_entry_find_first(ea_block_cache, hash);
3036         while (ce) {
3037                 struct buffer_head *bh;
3038
3039                 bh = sb_bread(inode->i_sb, ce->e_value);
3040                 if (!bh) {
3041                         EXT4_ERROR_INODE(inode, "block %lu read error",
3042                                          (unsigned long)ce->e_value);
3043                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3044                         *pce = ce;
3045                         return bh;
3046                 }
3047                 brelse(bh);
3048                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3049         }
3050         return NULL;
3051 }
3052
3053 #define NAME_HASH_SHIFT 5
3054 #define VALUE_HASH_SHIFT 16
3055
3056 /*
3057  * ext4_xattr_hash_entry()
3058  *
3059  * Compute the hash of an extended attribute.
3060  */
3061 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3062                                     size_t value_count)
3063 {
3064         __u32 hash = 0;
3065
3066         while (name_len--) {
3067                 hash = (hash << NAME_HASH_SHIFT) ^
3068                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3069                        *name++;
3070         }
3071         while (value_count--) {
3072                 hash = (hash << VALUE_HASH_SHIFT) ^
3073                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3074                        le32_to_cpu(*value++);
3075         }
3076         return cpu_to_le32(hash);
3077 }
3078
3079 #undef NAME_HASH_SHIFT
3080 #undef VALUE_HASH_SHIFT
3081
3082 #define BLOCK_HASH_SHIFT 16
3083
3084 /*
3085  * ext4_xattr_rehash()
3086  *
3087  * Re-compute the extended attribute hash value after an entry has changed.
3088  */
3089 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3090 {
3091         struct ext4_xattr_entry *here;
3092         __u32 hash = 0;
3093
3094         here = ENTRY(header+1);
3095         while (!IS_LAST_ENTRY(here)) {
3096                 if (!here->e_hash) {
3097                         /* Block is not shared if an entry's hash value == 0 */
3098                         hash = 0;
3099                         break;
3100                 }
3101                 hash = (hash << BLOCK_HASH_SHIFT) ^
3102                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3103                        le32_to_cpu(here->e_hash);
3104                 here = EXT4_XATTR_NEXT(here);
3105         }
3106         header->h_hash = cpu_to_le32(hash);
3107 }
3108
3109 #undef BLOCK_HASH_SHIFT
3110
3111 #define HASH_BUCKET_BITS        10
3112
3113 struct mb_cache *
3114 ext4_xattr_create_cache(void)
3115 {
3116         return mb_cache_create(HASH_BUCKET_BITS);
3117 }
3118
3119 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3120 {
3121         if (cache)
3122                 mb_cache_destroy(cache);
3123 }
3124