fs/ext4/xattr.c

   1 /*
   2  * linux/fs/ext4/xattr.c
   3  *
   4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
   5  *
   6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
   7  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
   8  * Extended attributes for symlinks and special files added per
   9  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  10  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  11  *  Red Hat Inc.
  12  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
  13  *  and Andreas Gruenbacher <agruen@suse.de>.
  14  */
  15
  16 /*
  17  * Extended attributes are stored directly in inodes (on file systems with
  18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
  19  * field contains the block number if an inode uses an additional block. All
  20  * attributes must fit in the inode and one additional block. Blocks that
  21  * contain the identical set of attributes may be shared among several inodes.
  22  * Identical blocks are detected by keeping a cache of blocks that have
  23  * recently been accessed.
  24  *
  25  * The attributes in inodes and on blocks have a different header; the entries
  26  * are stored in the same format:
  27  *
  28  *   +------------------+
  29  *   | header           |
  30  *   | entry 1          | |
  31  *   | entry 2          | | growing downwards
  32  *   | entry 3          | v
  33  *   | four null bytes  |
  34  *   | . . .            |
  35  *   | value 1          | ^
  36  *   | value 3          | | growing upwards
  37  *   | value 2          | |
  38  *   +------------------+
  39  *
  40  * The header is followed by multiple entry descriptors. In disk blocks, the
  41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
  42  * attribute values are aligned to the end of the block in no specific order.
  43  *
  44  * Locking strategy
  45  * ----------------
  46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
  47  * EA blocks are only changed if they are exclusive to an inode, so
  48  * holding xattr_sem also means that nothing but the EA block's reference
  49  * count can change. Multiple writers to the same block are synchronized
  50  * by the buffer lock.
  51  */
  52
  53 #include <linux/init.h>
  54 #include <linux/fs.h>
  55 #include <linux/slab.h>
  56 #include <linux/mbcache.h>
  57 #include <linux/quotaops.h>
  58 #include "ext4_jbd2.h"
  59 #include "ext4.h"
  60 #include "xattr.h"
  61 #include "acl.h"
  62
  63 #ifdef EXT4_XATTR_DEBUG
  64 # define ea_idebug(inode, fmt, ...)                                     \
  65         printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",                    \
  66                inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
  67 # define ea_bdebug(bh, fmt, ...)                                        \
  68         printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",                   \
  69                bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
  70 #else
  71 # define ea_idebug(inode, fmt, ...)     no_printk(fmt, ##__VA_ARGS__)
  72 # define ea_bdebug(bh, fmt, ...)        no_printk(fmt, ##__VA_ARGS__)
  73 #endif
  74
  75 static void ext4_xattr_block_cache_insert(struct mb_cache *,
  76                                           struct buffer_head *);
  77 static struct buffer_head *
  78 ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
  79                             struct mb_cache_entry **);
  80 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
  81                                     size_t value_count);
  82 static void ext4_xattr_rehash(struct ext4_xattr_header *);
  83
  84 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
  85         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
  86 #ifdef CONFIG_EXT4_FS_POSIX_ACL
  87         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
  88         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
  89 #endif
  90         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
  91 #ifdef CONFIG_EXT4_FS_SECURITY
  92         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
  93 #endif
  94 };
  95
  96 const struct xattr_handler *ext4_xattr_handlers[] = {
  97         &ext4_xattr_user_handler,
  98         &ext4_xattr_trusted_handler,
  99 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 100         &posix_acl_access_xattr_handler,
 101         &posix_acl_default_xattr_handler,
 102 #endif
 103 #ifdef CONFIG_EXT4_FS_SECURITY
 104         &ext4_xattr_security_handler,
 105 #endif
 106         NULL
 107 };
 108
 109 #define EA_BLOCK_CACHE(inode)   (((struct ext4_sb_info *) \
 110                                 inode->i_sb->s_fs_info)->s_ea_block_cache)
 111
 112 #define EA_INODE_CACHE(inode)   (((struct ext4_sb_info *) \
 113                                 inode->i_sb->s_fs_info)->s_ea_inode_cache)
 114
 115 static int
 116 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 117                         struct inode *inode);
 118
 119 #ifdef CONFIG_LOCKDEP
 120 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 121 {
 122         lockdep_set_subclass(&ea_inode->i_rwsem, 1);
 123 }
 124 #endif
 125
 126 static __le32 ext4_xattr_block_csum(struct inode *inode,
 127                                     sector_t block_nr,
 128                                     struct ext4_xattr_header *hdr)
 129 {
 130         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 131         __u32 csum;
 132         __le64 dsk_block_nr = cpu_to_le64(block_nr);
 133         __u32 dummy_csum = 0;
 134         int offset = offsetof(struct ext4_xattr_header, h_checksum);
 135
 136         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
 137                            sizeof(dsk_block_nr));
 138         csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
 139         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 140         offset += sizeof(dummy_csum);
 141         csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
 142                            EXT4_BLOCK_SIZE(inode->i_sb) - offset);
 143
 144         return cpu_to_le32(csum);
 145 }
 146
 147 static int ext4_xattr_block_csum_verify(struct inode *inode,
 148                                         struct buffer_head *bh)
 149 {
 150         struct ext4_xattr_header *hdr = BHDR(bh);
 151         int ret = 1;
 152
 153         if (ext4_has_metadata_csum(inode->i_sb)) {
 154                 lock_buffer(bh);
 155                 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
 156                                                         bh->b_blocknr, hdr));
 157                 unlock_buffer(bh);
 158         }
 159         return ret;
 160 }
 161
 162 static void ext4_xattr_block_csum_set(struct inode *inode,
 163                                       struct buffer_head *bh)
 164 {
 165         if (ext4_has_metadata_csum(inode->i_sb))
 166                 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
 167                                                 bh->b_blocknr, BHDR(bh));
 168 }
 169
 170 static inline const struct xattr_handler *
 171 ext4_xattr_handler(int name_index)
 172 {
 173         const struct xattr_handler *handler = NULL;
 174
 175         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
 176                 handler = ext4_xattr_handler_map[name_index];
 177         return handler;
 178 }
 179
 180 static int
 181 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
 182                          void *value_start)
 183 {
 184         struct ext4_xattr_entry *e = entry;
 185
 186         /* Find the end of the names list */
 187         while (!IS_LAST_ENTRY(e)) {
 188                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
 189                 if ((void *)next >= end)
 190                         return -EFSCORRUPTED;
 191                 e = next;
 192         }
 193
 194         /* Check the values */
 195         while (!IS_LAST_ENTRY(entry)) {
 196                 if (entry->e_value_size != 0 &&
 197                     entry->e_value_inum == 0) {
 198                         u16 offs = le16_to_cpu(entry->e_value_offs);
 199                         u32 size = le32_to_cpu(entry->e_value_size);
 200                         void *value;
 201
 202                         /*
 203                          * The value cannot overlap the names, and the value
 204                          * with padding cannot extend beyond 'end'.  Check both
 205                          * the padded and unpadded sizes, since the size may
 206                          * overflow to 0 when adding padding.
 207                          */
 208                         if (offs > end - value_start)
 209                                 return -EFSCORRUPTED;
 210                         value = value_start + offs;
 211                         if (value < (void *)e + sizeof(u32) ||
 212                             size > end - value ||
 213                             EXT4_XATTR_SIZE(size) > end - value)
 214                                 return -EFSCORRUPTED;
 215                 }
 216                 entry = EXT4_XATTR_NEXT(entry);
 217         }
 218
 219         return 0;
 220 }
 221
 222 static inline int
 223 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 224 {
 225         int error;
 226
 227         if (buffer_verified(bh))
 228                 return 0;
 229
 230         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 231             BHDR(bh)->h_blocks != cpu_to_le32(1))
 232                 return -EFSCORRUPTED;
 233         if (!ext4_xattr_block_csum_verify(inode, bh))
 234                 return -EFSBADCRC;
 235         error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
 236                                          bh->b_data);
 237         if (!error)
 238                 set_buffer_verified(bh);
 239         return error;
 240 }
 241
 242 static int
 243 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
 244                          void *end, const char *function, unsigned int line)
 245 {
 246         int error = -EFSCORRUPTED;
 247
 248         if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
 249             (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
 250                 goto errout;
 251         error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
 252 errout:
 253         if (error)
 254                 __ext4_error_inode(inode, function, line, 0,
 255                                    "corrupted in-inode xattr");
 256         return error;
 257 }
 258
 259 #define xattr_check_inode(inode, header, end) \
 260         __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
 261
 262 static int
 263 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 264                       const char *name, int sorted)
 265 {
 266         struct ext4_xattr_entry *entry;
 267         size_t name_len;
 268         int cmp = 1;
 269
 270         if (name == NULL)
 271                 return -EINVAL;
 272         name_len = strlen(name);
 273         entry = *pentry;
 274         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 275                 cmp = name_index - entry->e_name_index;
 276                 if (!cmp)
 277                         cmp = name_len - entry->e_name_len;
 278                 if (!cmp)
 279                         cmp = memcmp(name, entry->e_name, name_len);
 280                 if (cmp <= 0 && (sorted || cmp == 0))
 281                         break;
 282         }
 283         *pentry = entry;
 284         return cmp ? -ENODATA : 0;
 285 }
 286
 287 static u32
 288 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
 289 {
 290         return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
 291 }
 292
 293 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
 294 {
 295         return ((u64)ea_inode->i_ctime.tv_sec << 32) |
 296                ((u32)ea_inode->i_version);
 297 }
 298
 299 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
 300 {
 301         ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
 302         ea_inode->i_version = (u32)ref_count;
 303 }
 304
 305 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
 306 {
 307         return (u32)ea_inode->i_atime.tv_sec;
 308 }
 309
 310 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
 311 {
 312         ea_inode->i_atime.tv_sec = hash;
 313 }
 314
 315 /*
 316  * Read the EA value from an inode.
 317  */
 318 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 319 {
 320         int blocksize = 1 << ea_inode->i_blkbits;
 321         int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
 322         int tail_size = (size % blocksize) ?: blocksize;
 323         struct buffer_head *bhs_inline[8];
 324         struct buffer_head **bhs = bhs_inline;
 325         int i, ret;
 326
 327         if (bh_count > ARRAY_SIZE(bhs_inline)) {
 328                 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
 329                 if (!bhs)
 330                         return -ENOMEM;
 331         }
 332
 333         ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
 334                                true /* wait */, bhs);
 335         if (ret)
 336                 goto free_bhs;
 337
 338         for (i = 0; i < bh_count; i++) {
 339                 /* There shouldn't be any holes in ea_inode. */
 340                 if (!bhs[i]) {
 341                         ret = -EFSCORRUPTED;
 342                         goto put_bhs;
 343                 }
 344                 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
 345                        i < bh_count - 1 ? blocksize : tail_size);
 346         }
 347         ret = 0;
 348 put_bhs:
 349         for (i = 0; i < bh_count; i++)
 350                 brelse(bhs[i]);
 351 free_bhs:
 352         if (bhs != bhs_inline)
 353                 kfree(bhs);
 354         return ret;
 355 }
 356
 357 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 358                                  struct inode **ea_inode)
 359 {
 360         struct inode *inode;
 361         int err;
 362
 363         inode = ext4_iget(parent->i_sb, ea_ino);
 364         if (IS_ERR(inode)) {
 365                 err = PTR_ERR(inode);
 366                 ext4_error(parent->i_sb,
 367                            "error while reading EA inode %lu err=%d", ea_ino,
 368                            err);
 369                 return err;
 370         }
 371
 372         if (is_bad_inode(inode)) {
 373                 ext4_error(parent->i_sb,
 374                            "error while reading EA inode %lu is_bad_inode",
 375                            ea_ino);
 376                 err = -EIO;
 377                 goto error;
 378         }
 379
 380         if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 381                 ext4_error(parent->i_sb,
 382                            "EA inode %lu does not have EXT4_EA_INODE_FL flag",
 383                             ea_ino);
 384                 err = -EINVAL;
 385                 goto error;
 386         }
 387
 388         *ea_inode = inode;
 389         return 0;
 390 error:
 391         iput(inode);
 392         return err;
 393 }
 394
 395 static int
 396 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
 397                                struct ext4_xattr_entry *entry, void *buffer,
 398                                size_t size)
 399 {
 400         u32 hash;
 401
 402         /* Verify stored hash matches calculated hash. */
 403         hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
 404         if (hash != ext4_xattr_inode_get_hash(ea_inode))
 405                 return -EFSCORRUPTED;
 406
 407         if (entry) {
 408                 __le32 e_hash, tmp_data;
 409
 410                 /* Verify entry hash. */
 411                 tmp_data = cpu_to_le32(hash);
 412                 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
 413                                                &tmp_data, 1);
 414                 if (e_hash != entry->e_hash)
 415                         return -EFSCORRUPTED;
 416         }
 417         return 0;
 418 }
 419
 420 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
 421
 422 /*
 423  * Read xattr value from the EA inode.
 424  */
 425 static int
 426 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
 427                      void *buffer, size_t size)
 428 {
 429         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 430         struct inode *ea_inode;
 431         int err;
 432
 433         err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
 434                                     &ea_inode);
 435         if (err) {
 436                 ea_inode = NULL;
 437                 goto out;
 438         }
 439
 440         if (i_size_read(ea_inode) != size) {
 441                 ext4_warning_inode(ea_inode,
 442                                    "ea_inode file size=%llu entry size=%zu",
 443                                    i_size_read(ea_inode), size);
 444                 err = -EFSCORRUPTED;
 445                 goto out;
 446         }
 447
 448         err = ext4_xattr_inode_read(ea_inode, buffer, size);
 449         if (err)
 450                 goto out;
 451
 452         err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer, size);
 453         /*
 454          * Compatibility check for old Lustre ea_inode implementation. Old
 455          * version does not have hash validation, but it has a backpointer
 456          * from ea_inode to the parent inode.
 457          */
 458         if (err == -EFSCORRUPTED) {
 459                 if (EXT4_XATTR_INODE_GET_PARENT(ea_inode) != inode->i_ino ||
 460                     ea_inode->i_generation != inode->i_generation) {
 461                         ext4_warning_inode(ea_inode,
 462                                            "EA inode hash validation failed");
 463                         goto out;
 464                 }
 465                 /* Do not add ea_inode to the cache. */
 466                 ea_inode_cache = NULL;
 467                 err = 0;
 468         } else if (err)
 469                 goto out;
 470
 471         if (ea_inode_cache)
 472                 mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
 473                                       ext4_xattr_inode_get_hash(ea_inode),
 474                                       ea_inode->i_ino, true /* reusable */);
 475 out:
 476         iput(ea_inode);
 477         return err;
 478 }
 479
 480 static int
 481 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 482                      void *buffer, size_t buffer_size)
 483 {
 484         struct buffer_head *bh = NULL;
 485         struct ext4_xattr_entry *entry;
 486         size_t size;
 487         int error;
 488         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
 489
 490         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
 491                   name_index, name, buffer, (long)buffer_size);
 492
 493         error = -ENODATA;
 494         if (!EXT4_I(inode)->i_file_acl)
 495                 goto cleanup;
 496         ea_idebug(inode, "reading block %llu",
 497                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 498         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 499         if (!bh)
 500                 goto cleanup;
 501         ea_bdebug(bh, "b_count=%d, refcount=%d",
 502                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 503         if (ext4_xattr_check_block(inode, bh)) {
 504                 EXT4_ERROR_INODE(inode, "bad block %llu",
 505                                  EXT4_I(inode)->i_file_acl);
 506                 error = -EFSCORRUPTED;
 507                 goto cleanup;
 508         }
 509         ext4_xattr_block_cache_insert(ea_block_cache, bh);
 510         entry = BFIRST(bh);
 511         error = ext4_xattr_find_entry(&entry, name_index, name, 1);
 512         if (error)
 513                 goto cleanup;
 514         size = le32_to_cpu(entry->e_value_size);
 515         if (buffer) {
 516                 error = -ERANGE;
 517                 if (size > buffer_size)
 518                         goto cleanup;
 519                 if (entry->e_value_inum) {
 520                         error = ext4_xattr_inode_get(inode, entry, buffer,
 521                                                      size);
 522                         if (error)
 523                                 goto cleanup;
 524                 } else {
 525                         memcpy(buffer, bh->b_data +
 526                                le16_to_cpu(entry->e_value_offs), size);
 527                 }
 528         }
 529         error = size;
 530
 531 cleanup:
 532         brelse(bh);
 533         return error;
 534 }
 535
 536 int
 537 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 538                      void *buffer, size_t buffer_size)
 539 {
 540         struct ext4_xattr_ibody_header *header;
 541         struct ext4_xattr_entry *entry;
 542         struct ext4_inode *raw_inode;
 543         struct ext4_iloc iloc;
 544         size_t size;
 545         void *end;
 546         int error;
 547
 548         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 549                 return -ENODATA;
 550         error = ext4_get_inode_loc(inode, &iloc);
 551         if (error)
 552                 return error;
 553         raw_inode = ext4_raw_inode(&iloc);
 554         header = IHDR(inode, raw_inode);
 555         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 556         error = xattr_check_inode(inode, header, end);
 557         if (error)
 558                 goto cleanup;
 559         entry = IFIRST(header);
 560         error = ext4_xattr_find_entry(&entry, name_index, name, 0);
 561         if (error)
 562                 goto cleanup;
 563         size = le32_to_cpu(entry->e_value_size);
 564         if (buffer) {
 565                 error = -ERANGE;
 566                 if (size > buffer_size)
 567                         goto cleanup;
 568                 if (entry->e_value_inum) {
 569                         error = ext4_xattr_inode_get(inode, entry, buffer,
 570                                                      size);
 571                         if (error)
 572                                 goto cleanup;
 573                 } else {
 574                         memcpy(buffer, (void *)IFIRST(header) +
 575                                le16_to_cpu(entry->e_value_offs), size);
 576                 }
 577         }
 578         error = size;
 579
 580 cleanup:
 581         brelse(iloc.bh);
 582         return error;
 583 }
 584
 585 /*
 586  * ext4_xattr_get()
 587  *
 588  * Copy an extended attribute into the buffer
 589  * provided, or compute the buffer size required.
 590  * Buffer is NULL to compute the size of the buffer required.
 591  *
 592  * Returns a negative error number on failure, or the number of bytes
 593  * used / required on success.
 594  */
 595 int
 596 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 597                void *buffer, size_t buffer_size)
 598 {
 599         int error;
 600
 601         if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 602                 return -EIO;
 603
 604         if (strlen(name) > 255)
 605                 return -ERANGE;
 606
 607         down_read(&EXT4_I(inode)->xattr_sem);
 608         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 609                                      buffer_size);
 610         if (error == -ENODATA)
 611                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
 612                                              buffer_size);
 613         up_read(&EXT4_I(inode)->xattr_sem);
 614         return error;
 615 }
 616
 617 static int
 618 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
 619                         char *buffer, size_t buffer_size)
 620 {
 621         size_t rest = buffer_size;
 622
 623         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
 624                 const struct xattr_handler *handler =
 625                         ext4_xattr_handler(entry->e_name_index);
 626
 627                 if (handler && (!handler->list || handler->list(dentry))) {
 628                         const char *prefix = handler->prefix ?: handler->name;
 629                         size_t prefix_len = strlen(prefix);
 630                         size_t size = prefix_len + entry->e_name_len + 1;
 631
 632                         if (buffer) {
 633                                 if (size > rest)
 634                                         return -ERANGE;
 635                                 memcpy(buffer, prefix, prefix_len);
 636                                 buffer += prefix_len;
 637                                 memcpy(buffer, entry->e_name, entry->e_name_len);
 638                                 buffer += entry->e_name_len;
 639                                 *buffer++ = 0;
 640                         }
 641                         rest -= size;
 642                 }
 643         }
 644         return buffer_size - rest;  /* total size */
 645 }
 646
 647 static int
 648 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 649 {
 650         struct inode *inode = d_inode(dentry);
 651         struct buffer_head *bh = NULL;
 652         int error;
 653
 654         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 655                   buffer, (long)buffer_size);
 656
 657         error = 0;
 658         if (!EXT4_I(inode)->i_file_acl)
 659                 goto cleanup;
 660         ea_idebug(inode, "reading block %llu",
 661                   (unsigned long long)EXT4_I(inode)->i_file_acl);
 662         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 663         error = -EIO;
 664         if (!bh)
 665                 goto cleanup;
 666         ea_bdebug(bh, "b_count=%d, refcount=%d",
 667                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
 668         if (ext4_xattr_check_block(inode, bh)) {
 669                 EXT4_ERROR_INODE(inode, "bad block %llu",
 670                                  EXT4_I(inode)->i_file_acl);
 671                 error = -EFSCORRUPTED;
 672                 goto cleanup;
 673         }
 674         ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
 675         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 676
 677 cleanup:
 678         brelse(bh);
 679
 680         return error;
 681 }
 682
 683 static int
 684 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 685 {
 686         struct inode *inode = d_inode(dentry);
 687         struct ext4_xattr_ibody_header *header;
 688         struct ext4_inode *raw_inode;
 689         struct ext4_iloc iloc;
 690         void *end;
 691         int error;
 692
 693         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 694                 return 0;
 695         error = ext4_get_inode_loc(inode, &iloc);
 696         if (error)
 697                 return error;
 698         raw_inode = ext4_raw_inode(&iloc);
 699         header = IHDR(inode, raw_inode);
 700         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 701         error = xattr_check_inode(inode, header, end);
 702         if (error)
 703                 goto cleanup;
 704         error = ext4_xattr_list_entries(dentry, IFIRST(header),
 705                                         buffer, buffer_size);
 706
 707 cleanup:
 708         brelse(iloc.bh);
 709         return error;
 710 }
 711
 712 /*
 713  * Inode operation listxattr()
 714  *
 715  * d_inode(dentry)->i_rwsem: don't care
 716  *
 717  * Copy a list of attribute names into the buffer
 718  * provided, or compute the buffer size required.
 719  * Buffer is NULL to compute the size of the buffer required.
 720  *
 721  * Returns a negative error number on failure, or the number of bytes
 722  * used / required on success.
 723  */
 724 ssize_t
 725 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 726 {
 727         int ret, ret2;
 728
 729         down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 730         ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
 731         if (ret < 0)
 732                 goto errout;
 733         if (buffer) {
 734                 buffer += ret;
 735                 buffer_size -= ret;
 736         }
 737         ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 738         if (ret < 0)
 739                 goto errout;
 740         ret += ret2;
 741 errout:
 742         up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 743         return ret;
 744 }
 745
 746 /*
 747  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
 748  * not set, set it.
 749  */
 750 static void ext4_xattr_update_super_block(handle_t *handle,
 751                                           struct super_block *sb)
 752 {
 753         if (ext4_has_feature_xattr(sb))
 754                 return;
 755
 756         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
 757         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
 758                 ext4_set_feature_xattr(sb);
 759                 ext4_handle_dirty_super(handle, sb);
 760         }
 761 }
 762
 763 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
 764 {
 765         struct ext4_iloc iloc = { .bh = NULL };
 766         struct buffer_head *bh = NULL;
 767         struct ext4_inode *raw_inode;
 768         struct ext4_xattr_ibody_header *header;
 769         struct ext4_xattr_entry *entry;
 770         qsize_t ea_inode_refs = 0;
 771         void *end;
 772         int ret;
 773
 774         lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
 775
 776         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 777                 ret = ext4_get_inode_loc(inode, &iloc);
 778                 if (ret)
 779                         goto out;
 780                 raw_inode = ext4_raw_inode(&iloc);
 781                 header = IHDR(inode, raw_inode);
 782                 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
 783                 ret = xattr_check_inode(inode, header, end);
 784                 if (ret)
 785                         goto out;
 786
 787                 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
 788                      entry = EXT4_XATTR_NEXT(entry))
 789                         if (entry->e_value_inum)
 790                                 ea_inode_refs++;
 791         }
 792
 793         if (EXT4_I(inode)->i_file_acl) {
 794                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 795                 if (!bh) {
 796                         ret = -EIO;
 797                         goto out;
 798                 }
 799
 800                 if (ext4_xattr_check_block(inode, bh)) {
 801                         ret = -EFSCORRUPTED;
 802                         goto out;
 803                 }
 804
 805                 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
 806                      entry = EXT4_XATTR_NEXT(entry))
 807                         if (entry->e_value_inum)
 808                                 ea_inode_refs++;
 809         }
 810         *usage = ea_inode_refs + 1;
 811         ret = 0;
 812 out:
 813         brelse(iloc.bh);
 814         brelse(bh);
 815         return ret;
 816 }
 817
 818 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 819 {
 820         struct super_block *sb = inode->i_sb;
 821         size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
 822                                     inode->i_blkbits);
 823         size_t mask = ~(cluster_size - 1);
 824
 825         return (length + cluster_size - 1) & mask;
 826 }
 827
 828 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
 829 {
 830         int err;
 831
 832         err = dquot_alloc_inode(inode);
 833         if (err)
 834                 return err;
 835         err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
 836         if (err)
 837                 dquot_free_inode(inode);
 838         return err;
 839 }
 840
 841 static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
 842 {
 843         dquot_free_space_nodirty(inode, round_up_cluster(inode, len));
 844         dquot_free_inode(inode);
 845 }
 846
 847 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
 848                              struct buffer_head *block_bh, size_t value_len,
 849                              bool is_create)
 850 {
 851         int credits;
 852         int blocks;
 853
 854         /*
 855          * 1) Owner inode update
 856          * 2) Ref count update on old xattr block
 857          * 3) new xattr block
 858          * 4) block bitmap update for new xattr block
 859          * 5) group descriptor for new xattr block
 860          * 6) block bitmap update for old xattr block
 861          * 7) group descriptor for old block
 862          *
 863          * 6 & 7 can happen if we have two racing threads T_a and T_b
 864          * which are each trying to set an xattr on inodes I_a and I_b
 865          * which were both initially sharing an xattr block.
 866          */
 867         credits = 7;
 868
 869         /* Quota updates. */
 870         credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 871
 872         /*
 873          * In case of inline data, we may push out the data to a block,
 874          * so we need to reserve credits for this eventuality
 875          */
 876         if (inode && ext4_has_inline_data(inode))
 877                 credits += ext4_writepage_trans_blocks(inode) + 1;
 878
 879         /* We are done if ea_inode feature is not enabled. */
 880         if (!ext4_has_feature_ea_inode(sb))
 881                 return credits;
 882
 883         /* New ea_inode, inode map, block bitmap, group descriptor. */
 884         credits += 4;
 885
 886         /* Data blocks. */
 887         blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 888
 889         /* Indirection block or one level of extent tree. */
 890         blocks += 1;
 891
 892         /* Block bitmap and group descriptor updates for each block. */
 893         credits += blocks * 2;
 894
 895         /* Blocks themselves. */
 896         credits += blocks;
 897
 898         if (!is_create) {
 899                 /* Dereference ea_inode holding old xattr value.
 900                  * Old ea_inode, inode map, block bitmap, group descriptor.
 901                  */
 902                 credits += 4;
 903
 904                 /* Data blocks for old ea_inode. */
 905                 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
 906
 907                 /* Indirection block or one level of extent tree for old
 908                  * ea_inode.
 909                  */
 910                 blocks += 1;
 911
 912                 /* Block bitmap and group descriptor updates for each block. */
 913                 credits += blocks * 2;
 914         }
 915
 916         /* We may need to clone the existing xattr block in which case we need
 917          * to increment ref counts for existing ea_inodes referenced by it.
 918          */
 919         if (block_bh) {
 920                 struct ext4_xattr_entry *entry = BFIRST(block_bh);
 921
 922                 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
 923                         if (entry->e_value_inum)
 924                                 /* Ref count update on ea_inode. */
 925                                 credits += 1;
 926         }
 927         return credits;
 928 }
 929
 930 static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 931                                      int credits, struct buffer_head *bh,
 932                                      bool dirty, bool block_csum)
 933 {
 934         int error;
 935
 936         if (!ext4_handle_valid(handle))
 937                 return 0;
 938
 939         if (handle->h_buffer_credits >= credits)
 940                 return 0;
 941
 942         error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
 943         if (!error)
 944                 return 0;
 945         if (error < 0) {
 946                 ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
 947                 return error;
 948         }
 949
 950         if (bh && dirty) {
 951                 if (block_csum)
 952                         ext4_xattr_block_csum_set(inode, bh);
 953                 error = ext4_handle_dirty_metadata(handle, NULL, bh);
 954                 if (error) {
 955                         ext4_warning(inode->i_sb, "Handle metadata (error %d)",
 956                                      error);
 957                         return error;
 958                 }
 959         }
 960
 961         error = ext4_journal_restart(handle, credits);
 962         if (error) {
 963                 ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
 964                 return error;
 965         }
 966
 967         if (bh) {
 968                 error = ext4_journal_get_write_access(handle, bh);
 969                 if (error) {
 970                         ext4_warning(inode->i_sb,
 971                                      "Get write access failed (error %d)",
 972                                      error);
 973                         return error;
 974                 }
 975         }
 976         return 0;
 977 }
 978
 979 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 980                                        int ref_change)
 981 {
 982         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
 983         struct ext4_iloc iloc;
 984         s64 ref_count;
 985         u32 hash;
 986         int ret;
 987
 988         inode_lock(ea_inode);
 989
 990         ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
 991         if (ret) {
 992                 iloc.bh = NULL;
 993                 goto out;
 994         }
 995
 996         ref_count = ext4_xattr_inode_get_ref(ea_inode);
 997         ref_count += ref_change;
 998         ext4_xattr_inode_set_ref(ea_inode, ref_count);
 999
1000         if (ref_change > 0) {
1001                 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1002                           ea_inode->i_ino, ref_count);
1003
1004                 if (ref_count == 1) {
1005                         WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1006                                   ea_inode->i_ino, ea_inode->i_nlink);
1007
1008                         set_nlink(ea_inode, 1);
1009                         ext4_orphan_del(handle, ea_inode);
1010
1011                         if (ea_inode_cache) {
1012                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1013                                 mb_cache_entry_create(ea_inode_cache,
1014                                                       GFP_NOFS, hash,
1015                                                       ea_inode->i_ino,
1016                                                       true /* reusable */);
1017                         }
1018                 }
1019         } else {
1020                 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1021                           ea_inode->i_ino, ref_count);
1022
1023                 if (ref_count == 0) {
1024                         WARN_ONCE(ea_inode->i_nlink != 1,
1025                                   "EA inode %lu i_nlink=%u",
1026                                   ea_inode->i_ino, ea_inode->i_nlink);
1027
1028                         clear_nlink(ea_inode);
1029                         ext4_orphan_add(handle, ea_inode);
1030
1031                         if (ea_inode_cache) {
1032                                 hash = ext4_xattr_inode_get_hash(ea_inode);
1033                                 mb_cache_entry_delete(ea_inode_cache, hash,
1034                                                       ea_inode->i_ino);
1035                         }
1036                 }
1037         }
1038
1039         ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1040         iloc.bh = NULL;
1041         if (ret)
1042                 ext4_warning_inode(ea_inode,
1043                                    "ext4_mark_iloc_dirty() failed ret=%d", ret);
1044 out:
1045         brelse(iloc.bh);
1046         inode_unlock(ea_inode);
1047         return ret;
1048 }
1049
1050 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1051 {
1052         return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1053 }
1054
1055 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1056 {
1057         return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1058 }
1059
1060 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1061                                         struct ext4_xattr_entry *first)
1062 {
1063         struct inode *ea_inode;
1064         struct ext4_xattr_entry *entry;
1065         struct ext4_xattr_entry *failed_entry;
1066         unsigned int ea_ino;
1067         int err, saved_err;
1068
1069         for (entry = first; !IS_LAST_ENTRY(entry);
1070              entry = EXT4_XATTR_NEXT(entry)) {
1071                 if (!entry->e_value_inum)
1072                         continue;
1073                 ea_ino = le32_to_cpu(entry->e_value_inum);
1074                 err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
1075                 if (err)
1076                         goto cleanup;
1077                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1078                 if (err) {
1079                         ext4_warning_inode(ea_inode, "inc ref error %d", err);
1080                         iput(ea_inode);
1081                         goto cleanup;
1082                 }
1083                 iput(ea_inode);
1084         }
1085         return 0;
1086
1087 cleanup:
1088         saved_err = err;
1089         failed_entry = entry;
1090
1091         for (entry = first; entry != failed_entry;
1092              entry = EXT4_XATTR_NEXT(entry)) {
1093                 if (!entry->e_value_inum)
1094                         continue;
1095                 ea_ino = le32_to_cpu(entry->e_value_inum);
1096                 err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
1097                 if (err) {
1098                         ext4_warning(parent->i_sb,
1099                                      "cleanup ea_ino %u iget error %d", ea_ino,
1100                                      err);
1101                         continue;
1102                 }
1103                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1104                 if (err)
1105                         ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1106                                            err);
1107                 iput(ea_inode);
1108         }
1109         return saved_err;
1110 }
1111
1112 static void
1113 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1114                              struct buffer_head *bh,
1115                              struct ext4_xattr_entry *first, bool block_csum,
1116                              struct ext4_xattr_inode_array **ea_inode_array,
1117                              int extra_credits, bool skip_quota)
1118 {
1119         struct inode *ea_inode;
1120         struct ext4_xattr_entry *entry;
1121         bool dirty = false;
1122         unsigned int ea_ino;
1123         int err;
1124         int credits;
1125
1126         /* One credit for dec ref on ea_inode, one for orphan list addition, */
1127         credits = 2 + extra_credits;
1128
1129         for (entry = first; !IS_LAST_ENTRY(entry);
1130              entry = EXT4_XATTR_NEXT(entry)) {
1131                 if (!entry->e_value_inum)
1132                         continue;
1133                 ea_ino = le32_to_cpu(entry->e_value_inum);
1134                 err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
1135                 if (err)
1136                         continue;
1137
1138                 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1139                 if (err) {
1140                         ext4_warning_inode(ea_inode,
1141                                            "Expand inode array err=%d", err);
1142                         iput(ea_inode);
1143                         continue;
1144                 }
1145
1146                 err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
1147                                                 dirty, block_csum);
1148                 if (err) {
1149                         ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1150                                            err);
1151                         continue;
1152                 }
1153
1154                 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1155                 if (err) {
1156                         ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1157                                            err);
1158                         continue;
1159                 }
1160
1161                 if (!skip_quota)
1162                         ext4_xattr_inode_free_quota(parent,
1163                                               le32_to_cpu(entry->e_value_size));
1164
1165                 /*
1166                  * Forget about ea_inode within the same transaction that
1167                  * decrements the ref count. This avoids duplicate decrements in
1168                  * case the rest of the work spills over to subsequent
1169                  * transactions.
1170                  */
1171                 entry->e_value_inum = 0;
1172                 entry->e_value_size = 0;
1173
1174                 dirty = true;
1175         }
1176
1177         if (dirty) {
1178                 /*
1179                  * Note that we are deliberately skipping csum calculation for
1180                  * the final update because we do not expect any journal
1181                  * restarts until xattr block is freed.
1182                  */
1183
1184                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1185                 if (err)
1186                         ext4_warning_inode(parent,
1187                                            "handle dirty metadata err=%d", err);
1188         }
1189 }
1190
1191 /*
1192  * Release the xattr block BH: If the reference count is > 1, decrement it;
1193  * otherwise free the block.
1194  */
1195 static void
1196 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1197                          struct buffer_head *bh,
1198                          struct ext4_xattr_inode_array **ea_inode_array,
1199                          int extra_credits)
1200 {
1201         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1202         u32 hash, ref;
1203         int error = 0;
1204
1205         BUFFER_TRACE(bh, "get_write_access");
1206         error = ext4_journal_get_write_access(handle, bh);
1207         if (error)
1208                 goto out;
1209
1210         lock_buffer(bh);
1211         hash = le32_to_cpu(BHDR(bh)->h_hash);
1212         ref = le32_to_cpu(BHDR(bh)->h_refcount);
1213         if (ref == 1) {
1214                 ea_bdebug(bh, "refcount now=0; freeing");
1215                 /*
1216                  * This must happen under buffer lock for
1217                  * ext4_xattr_block_set() to reliably detect freed block
1218                  */
1219                 if (ea_block_cache)
1220                         mb_cache_entry_delete(ea_block_cache, hash,
1221                                               bh->b_blocknr);
1222                 get_bh(bh);
1223                 unlock_buffer(bh);
1224
1225                 if (ext4_has_feature_ea_inode(inode->i_sb))
1226                         ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1227                                                      BFIRST(bh),
1228                                                      true /* block_csum */,
1229                                                      ea_inode_array,
1230                                                      extra_credits,
1231                                                      true /* skip_quota */);
1232                 ext4_free_blocks(handle, inode, bh, 0, 1,
1233                                  EXT4_FREE_BLOCKS_METADATA |
1234                                  EXT4_FREE_BLOCKS_FORGET);
1235         } else {
1236                 ref--;
1237                 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1238                 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1239                         struct mb_cache_entry *ce;
1240
1241                         if (ea_block_cache) {
1242                                 ce = mb_cache_entry_get(ea_block_cache, hash,
1243                                                         bh->b_blocknr);
1244                                 if (ce) {
1245                                         ce->e_reusable = 1;
1246                                         mb_cache_entry_put(ea_block_cache, ce);
1247                                 }
1248                         }
1249                 }
1250
1251                 ext4_xattr_block_csum_set(inode, bh);
1252                 /*
1253                  * Beware of this ugliness: Releasing of xattr block references
1254                  * from different inodes can race and so we have to protect
1255                  * from a race where someone else frees the block (and releases
1256                  * its journal_head) before we are done dirtying the buffer. In
1257                  * nojournal mode this race is harmless and we actually cannot
1258                  * call ext4_handle_dirty_metadata() with locked buffer as
1259                  * that function can call sync_dirty_buffer() so for that case
1260                  * we handle the dirtying after unlocking the buffer.
1261                  */
1262                 if (ext4_handle_valid(handle))
1263                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1264                 unlock_buffer(bh);
1265                 if (!ext4_handle_valid(handle))
1266                         error = ext4_handle_dirty_metadata(handle, inode, bh);
1267                 if (IS_SYNC(inode))
1268                         ext4_handle_sync(handle);
1269                 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1270                 ea_bdebug(bh, "refcount now=%d; releasing",
1271                           le32_to_cpu(BHDR(bh)->h_refcount));
1272         }
1273 out:
1274         ext4_std_error(inode->i_sb, error);
1275         return;
1276 }
1277
1278 /*
1279  * Find the available free space for EAs. This also returns the total number of
1280  * bytes used by EA entries.
1281  */
1282 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1283                                     size_t *min_offs, void *base, int *total)
1284 {
1285         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1286                 if (!last->e_value_inum && last->e_value_size) {
1287                         size_t offs = le16_to_cpu(last->e_value_offs);
1288                         if (offs < *min_offs)
1289                                 *min_offs = offs;
1290                 }
1291                 if (total)
1292                         *total += EXT4_XATTR_LEN(last->e_name_len);
1293         }
1294         return (*min_offs - ((void *)last - base) - sizeof(__u32));
1295 }
1296
1297 /*
1298  * Write the value of the EA in an inode.
1299  */
1300 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1301                                   const void *buf, int bufsize)
1302 {
1303         struct buffer_head *bh = NULL;
1304         unsigned long block = 0;
1305         int blocksize = ea_inode->i_sb->s_blocksize;
1306         int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1307         int csize, wsize = 0;
1308         int ret = 0;
1309         int retries = 0;
1310
1311 retry:
1312         while (ret >= 0 && ret < max_blocks) {
1313                 struct ext4_map_blocks map;
1314                 map.m_lblk = block += ret;
1315                 map.m_len = max_blocks -= ret;
1316
1317                 ret = ext4_map_blocks(handle, ea_inode, &map,
1318                                       EXT4_GET_BLOCKS_CREATE);
1319                 if (ret <= 0) {
1320                         ext4_mark_inode_dirty(handle, ea_inode);
1321                         if (ret == -ENOSPC &&
1322                             ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1323                                 ret = 0;
1324                                 goto retry;
1325                         }
1326                         break;
1327                 }
1328         }
1329
1330         if (ret < 0)
1331                 return ret;
1332
1333         block = 0;
1334         while (wsize < bufsize) {
1335                 if (bh != NULL)
1336                         brelse(bh);
1337                 csize = (bufsize - wsize) > blocksize ? blocksize :
1338                                                                 bufsize - wsize;
1339                 bh = ext4_getblk(handle, ea_inode, block, 0);
1340                 if (IS_ERR(bh))
1341                         return PTR_ERR(bh);
1342                 ret = ext4_journal_get_write_access(handle, bh);
1343                 if (ret)
1344                         goto out;
1345
1346                 memcpy(bh->b_data, buf, csize);
1347                 set_buffer_uptodate(bh);
1348                 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1349
1350                 buf += csize;
1351                 wsize += csize;
1352                 block += 1;
1353         }
1354
1355         inode_lock(ea_inode);
1356         i_size_write(ea_inode, wsize);
1357         ext4_update_i_disksize(ea_inode, wsize);
1358         inode_unlock(ea_inode);
1359
1360         ext4_mark_inode_dirty(handle, ea_inode);
1361
1362 out:
1363         brelse(bh);
1364
1365         return ret;
1366 }
1367
1368 /*
1369  * Create an inode to store the value of a large EA.
1370  */
1371 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1372                                              struct inode *inode, u32 hash)
1373 {
1374         struct inode *ea_inode = NULL;
1375         uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1376         int err;
1377
1378         /*
1379          * Let the next inode be the goal, so we try and allocate the EA inode
1380          * in the same group, or nearby one.
1381          */
1382         ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1383                                   S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1384                                   EXT4_EA_INODE_FL);
1385         if (!IS_ERR(ea_inode)) {
1386                 ea_inode->i_op = &ext4_file_inode_operations;
1387                 ea_inode->i_fop = &ext4_file_operations;
1388                 ext4_set_aops(ea_inode);
1389                 ext4_xattr_inode_set_class(ea_inode);
1390                 unlock_new_inode(ea_inode);
1391                 ext4_xattr_inode_set_ref(ea_inode, 1);
1392                 ext4_xattr_inode_set_hash(ea_inode, hash);
1393                 err = ext4_mark_inode_dirty(handle, ea_inode);
1394                 if (!err)
1395                         err = ext4_inode_attach_jinode(ea_inode);
1396                 if (err) {
1397                         iput(ea_inode);
1398                         return ERR_PTR(err);
1399                 }
1400
1401                 /*
1402                  * Xattr inodes are shared therefore quota charging is performed
1403                  * at a higher level.
1404                  */
1405                 dquot_free_inode(ea_inode);
1406                 dquot_drop(ea_inode);
1407                 inode_lock(ea_inode);
1408                 ea_inode->i_flags |= S_NOQUOTA;
1409                 inode_unlock(ea_inode);
1410         }
1411
1412         return ea_inode;
1413 }
1414
1415 static struct inode *
1416 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1417                             size_t value_len, u32 hash)
1418 {
1419         struct inode *ea_inode;
1420         struct mb_cache_entry *ce;
1421         struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1422         void *ea_data;
1423
1424         if (!ea_inode_cache)
1425                 return NULL;
1426
1427         ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1428         if (!ce)
1429                 return NULL;
1430
1431         ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
1432         if (!ea_data) {
1433                 mb_cache_entry_put(ea_inode_cache, ce);
1434                 return NULL;
1435         }
1436
1437         while (ce) {
1438                 ea_inode = ext4_iget(inode->i_sb, ce->e_value);
1439                 if (!IS_ERR(ea_inode) &&
1440                     !is_bad_inode(ea_inode) &&
1441                     (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1442                     i_size_read(ea_inode) == value_len &&
1443                     !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1444                     !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1445                                                     value_len) &&
1446                     !memcmp(value, ea_data, value_len)) {
1447                         mb_cache_entry_touch(ea_inode_cache, ce);
1448                         mb_cache_entry_put(ea_inode_cache, ce);
1449                         kvfree(ea_data);
1450                         return ea_inode;
1451                 }
1452
1453                 if (!IS_ERR(ea_inode))
1454                         iput(ea_inode);
1455                 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1456         }
1457         kvfree(ea_data);
1458         return NULL;
1459 }
1460
1461 /*
1462  * Add value of the EA in an inode.
1463  */
1464 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1465                                           const void *value, size_t value_len,
1466                                           struct inode **ret_inode)
1467 {
1468         struct inode *ea_inode;
1469         u32 hash;
1470         int err;
1471
1472         hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1473         ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1474         if (ea_inode) {
1475                 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1476                 if (err) {
1477                         iput(ea_inode);
1478                         return err;
1479                 }
1480
1481                 *ret_inode = ea_inode;
1482                 return 0;
1483         }
1484
1485         /* Create an inode for the EA value */
1486         ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1487         if (IS_ERR(ea_inode))
1488                 return PTR_ERR(ea_inode);
1489
1490         err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1491         if (err) {
1492                 ext4_xattr_inode_dec_ref(handle, ea_inode);
1493                 iput(ea_inode);
1494                 return err;
1495         }
1496
1497         if (EA_INODE_CACHE(inode))
1498                 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1499                                       ea_inode->i_ino, true /* reusable */);
1500
1501         *ret_inode = ea_inode;
1502         return 0;
1503 }
1504
1505 /*
1506  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1507  * feature is enabled.
1508  */
1509 #define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1510
1511 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1512                                 struct ext4_xattr_search *s,
1513                                 handle_t *handle, struct inode *inode,
1514                                 bool is_block)
1515 {
1516         struct ext4_xattr_entry *last;
1517         struct ext4_xattr_entry *here = s->here;
1518         size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1519         int in_inode = i->in_inode;
1520         struct inode *old_ea_inode = NULL;
1521         struct inode *new_ea_inode = NULL;
1522         size_t old_size, new_size;
1523         int ret;
1524
1525         /* Space used by old and new values. */
1526         old_size = (!s->not_found && !here->e_value_inum) ?
1527                         EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1528         new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1529
1530         /*
1531          * Optimization for the simple case when old and new values have the
1532          * same padded sizes. Not applicable if external inodes are involved.
1533          */
1534         if (new_size && new_size == old_size) {
1535                 size_t offs = le16_to_cpu(here->e_value_offs);
1536                 void *val = s->base + offs;
1537
1538                 here->e_value_size = cpu_to_le32(i->value_len);
1539                 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1540                         memset(val, 0, new_size);
1541                 } else {
1542                         memcpy(val, i->value, i->value_len);
1543                         /* Clear padding bytes. */
1544                         memset(val + i->value_len, 0, new_size - i->value_len);
1545                 }
1546                 return 0;
1547         }
1548
1549         /* Compute min_offs and last. */
1550         last = s->first;
1551         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1552                 if (!last->e_value_inum && last->e_value_size) {
1553                         size_t offs = le16_to_cpu(last->e_value_offs);
1554                         if (offs < min_offs)
1555                                 min_offs = offs;
1556                 }
1557         }
1558
1559         /* Check whether we have enough space. */
1560         if (i->value) {
1561                 size_t free;
1562
1563                 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1564                 if (!s->not_found)
1565                         free += EXT4_XATTR_LEN(name_len) + old_size;
1566
1567                 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1568                         ret = -ENOSPC;
1569                         goto out;
1570                 }
1571
1572                 /*
1573                  * If storing the value in an external inode is an option,
1574                  * reserve space for xattr entries/names in the external
1575                  * attribute block so that a long value does not occupy the
1576                  * whole space and prevent futher entries being added.
1577                  */
1578                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1579                     new_size && is_block &&
1580                     (min_offs + old_size - new_size) <
1581                                         EXT4_XATTR_BLOCK_RESERVE(inode)) {
1582                         ret = -ENOSPC;
1583                         goto out;
1584                 }
1585         }
1586
1587         /*
1588          * Getting access to old and new ea inodes is subject to failures.
1589          * Finish that work before doing any modifications to the xattr data.
1590          */
1591         if (!s->not_found && here->e_value_inum) {
1592                 ret = ext4_xattr_inode_iget(inode,
1593                                             le32_to_cpu(here->e_value_inum),
1594                                             &old_ea_inode);
1595                 if (ret) {
1596                         old_ea_inode = NULL;
1597                         goto out;
1598                 }
1599         }
1600         if (i->value && in_inode) {
1601                 WARN_ON_ONCE(!i->value_len);
1602
1603                 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1604                 if (ret)
1605                         goto out;
1606
1607                 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1608                                                      i->value_len,
1609                                                      &new_ea_inode);
1610                 if (ret) {
1611                         new_ea_inode = NULL;
1612                         ext4_xattr_inode_free_quota(inode, i->value_len);
1613                         goto out;
1614                 }
1615         }
1616
1617         if (old_ea_inode) {
1618                 /* We are ready to release ref count on the old_ea_inode. */
1619                 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1620                 if (ret) {
1621                         /* Release newly required ref count on new_ea_inode. */
1622                         if (new_ea_inode) {
1623                                 int err;
1624
1625                                 err = ext4_xattr_inode_dec_ref(handle,
1626                                                                new_ea_inode);
1627                                 if (err)
1628                                         ext4_warning_inode(new_ea_inode,
1629                                                   "dec ref new_ea_inode err=%d",
1630                                                   err);
1631                                 ext4_xattr_inode_free_quota(inode,
1632                                                             i->value_len);
1633                         }
1634                         goto out;
1635                 }
1636
1637                 ext4_xattr_inode_free_quota(inode,
1638                                             le32_to_cpu(here->e_value_size));
1639         }
1640
1641         /* No failures allowed past this point. */
1642
1643         if (!s->not_found && here->e_value_offs) {
1644                 /* Remove the old value. */
1645                 void *first_val = s->base + min_offs;
1646                 size_t offs = le16_to_cpu(here->e_value_offs);
1647                 void *val = s->base + offs;
1648
1649                 memmove(first_val + old_size, first_val, val - first_val);
1650                 memset(first_val, 0, old_size);
1651                 min_offs += old_size;
1652
1653                 /* Adjust all value offsets. */
1654                 last = s->first;
1655                 while (!IS_LAST_ENTRY(last)) {
1656                         size_t o = le16_to_cpu(last->e_value_offs);
1657
1658                         if (!last->e_value_inum &&
1659                             last->e_value_size && o < offs)
1660                                 last->e_value_offs = cpu_to_le16(o + old_size);
1661                         last = EXT4_XATTR_NEXT(last);
1662                 }
1663         }
1664
1665         if (!i->value) {
1666                 /* Remove old name. */
1667                 size_t size = EXT4_XATTR_LEN(name_len);
1668
1669                 last = ENTRY((void *)last - size);
1670                 memmove(here, (void *)here + size,
1671                         (void *)last - (void *)here + sizeof(__u32));
1672                 memset(last, 0, size);
1673         } else if (s->not_found) {
1674                 /* Insert new name. */
1675                 size_t size = EXT4_XATTR_LEN(name_len);
1676                 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1677
1678                 memmove((void *)here + size, here, rest);
1679                 memset(here, 0, size);
1680                 here->e_name_index = i->name_index;
1681                 here->e_name_len = name_len;
1682                 memcpy(here->e_name, i->name, name_len);
1683         } else {
1684                 /* This is an update, reset value info. */
1685                 here->e_value_inum = 0;
1686                 here->e_value_offs = 0;
1687                 here->e_value_size = 0;
1688         }
1689
1690         if (i->value) {
1691                 /* Insert new value. */
1692                 if (in_inode) {
1693                         here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1694                 } else if (i->value_len) {
1695                         void *val = s->base + min_offs - new_size;
1696
1697                         here->e_value_offs = cpu_to_le16(min_offs - new_size);
1698                         if (i->value == EXT4_ZERO_XATTR_VALUE) {
1699                                 memset(val, 0, new_size);
1700                         } else {
1701                                 memcpy(val, i->value, i->value_len);
1702                                 /* Clear padding bytes. */
1703                                 memset(val + i->value_len, 0,
1704                                        new_size - i->value_len);
1705                         }
1706                 }
1707                 here->e_value_size = cpu_to_le32(i->value_len);
1708         }
1709
1710         if (i->value) {
1711                 __le32 hash = 0;
1712
1713                 /* Entry hash calculation. */
1714                 if (in_inode) {
1715                         __le32 crc32c_hash;
1716
1717                         /*
1718                          * Feed crc32c hash instead of the raw value for entry
1719                          * hash calculation. This is to avoid walking
1720                          * potentially long value buffer again.
1721                          */
1722                         crc32c_hash = cpu_to_le32(
1723                                        ext4_xattr_inode_get_hash(new_ea_inode));
1724                         hash = ext4_xattr_hash_entry(here->e_name,
1725                                                      here->e_name_len,
1726                                                      &crc32c_hash, 1);
1727                 } else if (is_block) {
1728                         __le32 *value = s->base + min_offs - new_size;
1729
1730                         hash = ext4_xattr_hash_entry(here->e_name,
1731                                                      here->e_name_len, value,
1732                                                      new_size >> 2);
1733                 }
1734                 here->e_hash = hash;
1735         }
1736
1737         if (is_block)
1738                 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1739
1740         ret = 0;
1741 out:
1742         iput(old_ea_inode);
1743         iput(new_ea_inode);
1744         return ret;
1745 }
1746
1747 struct ext4_xattr_block_find {
1748         struct ext4_xattr_search s;
1749         struct buffer_head *bh;
1750 };
1751
1752 static int
1753 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1754                       struct ext4_xattr_block_find *bs)
1755 {
1756         struct super_block *sb = inode->i_sb;
1757         int error;
1758
1759         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1760                   i->name_index, i->name, i->value, (long)i->value_len);
1761
1762         if (EXT4_I(inode)->i_file_acl) {
1763                 /* The inode already has an extended attribute block. */
1764                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
1765                 error = -EIO;
1766                 if (!bs->bh)
1767                         goto cleanup;
1768                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1769                         atomic_read(&(bs->bh->b_count)),
1770                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
1771                 if (ext4_xattr_check_block(inode, bs->bh)) {
1772                         EXT4_ERROR_INODE(inode, "bad block %llu",
1773                                          EXT4_I(inode)->i_file_acl);
1774                         error = -EFSCORRUPTED;
1775                         goto cleanup;
1776                 }
1777                 /* Find the named attribute. */
1778                 bs->s.base = BHDR(bs->bh);
1779                 bs->s.first = BFIRST(bs->bh);
1780                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1781                 bs->s.here = bs->s.first;
1782                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
1783                                               i->name, 1);
1784                 if (error && error != -ENODATA)
1785                         goto cleanup;
1786                 bs->s.not_found = error;
1787         }
1788         error = 0;
1789
1790 cleanup:
1791         return error;
1792 }
1793
1794 static int
1795 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1796                      struct ext4_xattr_info *i,
1797                      struct ext4_xattr_block_find *bs)
1798 {
1799         struct super_block *sb = inode->i_sb;
1800         struct buffer_head *new_bh = NULL;
1801         struct ext4_xattr_search s_copy = bs->s;
1802         struct ext4_xattr_search *s = &s_copy;
1803         struct mb_cache_entry *ce = NULL;
1804         int error = 0;
1805         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1806         struct inode *ea_inode = NULL;
1807         size_t old_ea_inode_size = 0;
1808
1809 #define header(x) ((struct ext4_xattr_header *)(x))
1810
1811         if (s->base) {
1812                 BUFFER_TRACE(bs->bh, "get_write_access");
1813                 error = ext4_journal_get_write_access(handle, bs->bh);
1814                 if (error)
1815                         goto cleanup;
1816                 lock_buffer(bs->bh);
1817
1818                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1819                         __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1820
1821                         /*
1822                          * This must happen under buffer lock for
1823                          * ext4_xattr_block_set() to reliably detect modified
1824                          * block
1825                          */
1826                         if (ea_block_cache)
1827                                 mb_cache_entry_delete(ea_block_cache, hash,
1828                                                       bs->bh->b_blocknr);
1829                         ea_bdebug(bs->bh, "modifying in-place");
1830                         error = ext4_xattr_set_entry(i, s, handle, inode,
1831                                                      true /* is_block */);
1832                         ext4_xattr_block_csum_set(inode, bs->bh);
1833                         unlock_buffer(bs->bh);
1834                         if (error == -EFSCORRUPTED)
1835                                 goto bad_block;
1836                         if (!error)
1837                                 error = ext4_handle_dirty_metadata(handle,
1838                                                                    inode,
1839                                                                    bs->bh);
1840                         if (error)
1841                                 goto cleanup;
1842                         goto inserted;
1843                 } else {
1844                         int offset = (char *)s->here - bs->bh->b_data;
1845
1846                         unlock_buffer(bs->bh);
1847                         ea_bdebug(bs->bh, "cloning");
1848                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1849                         error = -ENOMEM;
1850                         if (s->base == NULL)
1851                                 goto cleanup;
1852                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1853                         s->first = ENTRY(header(s->base)+1);
1854                         header(s->base)->h_refcount = cpu_to_le32(1);
1855                         s->here = ENTRY(s->base + offset);
1856                         s->end = s->base + bs->bh->b_size;
1857
1858                         /*
1859                          * If existing entry points to an xattr inode, we need
1860                          * to prevent ext4_xattr_set_entry() from decrementing
1861                          * ref count on it because the reference belongs to the
1862                          * original block. In this case, make the entry look
1863                          * like it has an empty value.
1864                          */
1865                         if (!s->not_found && s->here->e_value_inum) {
1866                                 /*
1867                                  * Defer quota free call for previous inode
1868                                  * until success is guaranteed.
1869                                  */
1870                                 old_ea_inode_size = le32_to_cpu(
1871                                                         s->here->e_value_size);
1872                                 s->here->e_value_inum = 0;
1873                                 s->here->e_value_size = 0;
1874                         }
1875                 }
1876         } else {
1877                 /* Allocate a buffer where we construct the new block. */
1878                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1879                 /* assert(header == s->base) */
1880                 error = -ENOMEM;
1881                 if (s->base == NULL)
1882                         goto cleanup;
1883                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1884                 header(s->base)->h_blocks = cpu_to_le32(1);
1885                 header(s->base)->h_refcount = cpu_to_le32(1);
1886                 s->first = ENTRY(header(s->base)+1);
1887                 s->here = ENTRY(header(s->base)+1);
1888                 s->end = s->base + sb->s_blocksize;
1889         }
1890
1891         error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1892         if (error == -EFSCORRUPTED)
1893                 goto bad_block;
1894         if (error)
1895                 goto cleanup;
1896
1897         if (i->value && s->here->e_value_inum) {
1898                 unsigned int ea_ino;
1899
1900                 /*
1901                  * A ref count on ea_inode has been taken as part of the call to
1902                  * ext4_xattr_set_entry() above. We would like to drop this
1903                  * extra ref but we have to wait until the xattr block is
1904                  * initialized and has its own ref count on the ea_inode.
1905                  */
1906                 ea_ino = le32_to_cpu(s->here->e_value_inum);
1907                 error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
1908                 if (error) {
1909                         ea_inode = NULL;
1910                         goto cleanup;
1911                 }
1912         }
1913
1914 inserted:
1915         if (!IS_LAST_ENTRY(s->first)) {
1916                 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1917                                                      &ce);
1918                 if (new_bh) {
1919                         /* We found an identical block in the cache. */
1920                         if (new_bh == bs->bh)
1921                                 ea_bdebug(new_bh, "keeping");
1922                         else {
1923                                 u32 ref;
1924
1925                                 WARN_ON_ONCE(dquot_initialize_needed(inode));
1926
1927                                 /* The old block is released after updating
1928                                    the inode. */
1929                                 error = dquot_alloc_block(inode,
1930                                                 EXT4_C2B(EXT4_SB(sb), 1));
1931                                 if (error)
1932                                         goto cleanup;
1933                                 BUFFER_TRACE(new_bh, "get_write_access");
1934                                 error = ext4_journal_get_write_access(handle,
1935                                                                       new_bh);
1936                                 if (error)
1937                                         goto cleanup_dquot;
1938                                 lock_buffer(new_bh);
1939                                 /*
1940                                  * We have to be careful about races with
1941                                  * freeing, rehashing or adding references to
1942                                  * xattr block. Once we hold buffer lock xattr
1943                                  * block's state is stable so we can check
1944                                  * whether the block got freed / rehashed or
1945                                  * not.  Since we unhash mbcache entry under
1946                                  * buffer lock when freeing / rehashing xattr
1947                                  * block, checking whether entry is still
1948                                  * hashed is reliable. Same rules hold for
1949                                  * e_reusable handling.
1950                                  */
1951                                 if (hlist_bl_unhashed(&ce->e_hash_list) ||
1952                                     !ce->e_reusable) {
1953                                         /*
1954                                          * Undo everything and check mbcache
1955                                          * again.
1956                                          */
1957                                         unlock_buffer(new_bh);
1958                                         dquot_free_block(inode,
1959                                                          EXT4_C2B(EXT4_SB(sb),
1960                                                                   1));
1961                                         brelse(new_bh);
1962                                         mb_cache_entry_put(ea_block_cache, ce);
1963                                         ce = NULL;
1964                                         new_bh = NULL;
1965                                         goto inserted;
1966                                 }
1967                                 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
1968                                 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
1969                                 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
1970                                         ce->e_reusable = 0;
1971                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
1972                                           ref);
1973                                 ext4_xattr_block_csum_set(inode, new_bh);
1974                                 unlock_buffer(new_bh);
1975                                 error = ext4_handle_dirty_metadata(handle,
1976                                                                    inode,
1977                                                                    new_bh);
1978                                 if (error)
1979                                         goto cleanup_dquot;
1980                         }
1981                         mb_cache_entry_touch(ea_block_cache, ce);
1982                         mb_cache_entry_put(ea_block_cache, ce);
1983                         ce = NULL;
1984                 } else if (bs->bh && s->base == bs->bh->b_data) {
1985                         /* We were modifying this block in-place. */
1986                         ea_bdebug(bs->bh, "keeping this block");
1987                         ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
1988                         new_bh = bs->bh;
1989                         get_bh(new_bh);
1990                 } else {
1991                         /* We need to allocate a new block */
1992                         ext4_fsblk_t goal, block;
1993
1994                         WARN_ON_ONCE(dquot_initialize_needed(inode));
1995
1996                         goal = ext4_group_first_block_no(sb,
1997                                                 EXT4_I(inode)->i_block_group);
1998
1999                         /* non-extent files can't have physical blocks past 2^32 */
2000                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2001                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2002
2003                         block = ext4_new_meta_blocks(handle, inode, goal, 0,
2004                                                      NULL, &error);
2005                         if (error)
2006                                 goto cleanup;
2007
2008                         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2009                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2010
2011                         ea_idebug(inode, "creating block %llu",
2012                                   (unsigned long long)block);
2013
2014                         new_bh = sb_getblk(sb, block);
2015                         if (unlikely(!new_bh)) {
2016                                 error = -ENOMEM;
2017 getblk_failed:
2018                                 ext4_free_blocks(handle, inode, NULL, block, 1,
2019                                                  EXT4_FREE_BLOCKS_METADATA);
2020                                 goto cleanup;
2021                         }
2022                         error = ext4_xattr_inode_inc_ref_all(handle, inode,
2023                                                       ENTRY(header(s->base)+1));
2024                         if (error)
2025                                 goto getblk_failed;
2026                         if (ea_inode) {
2027                                 /* Drop the extra ref on ea_inode. */
2028                                 error = ext4_xattr_inode_dec_ref(handle,
2029                                                                  ea_inode);
2030                                 if (error)
2031                                         ext4_warning_inode(ea_inode,
2032                                                            "dec ref error=%d",
2033                                                            error);
2034                                 iput(ea_inode);
2035                                 ea_inode = NULL;
2036                         }
2037
2038                         lock_buffer(new_bh);
2039                         error = ext4_journal_get_create_access(handle, new_bh);
2040                         if (error) {
2041                                 unlock_buffer(new_bh);
2042                                 error = -EIO;
2043                                 goto getblk_failed;
2044                         }
2045                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
2046                         ext4_xattr_block_csum_set(inode, new_bh);
2047                         set_buffer_uptodate(new_bh);
2048                         unlock_buffer(new_bh);
2049                         ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2050                         error = ext4_handle_dirty_metadata(handle, inode,
2051                                                            new_bh);
2052                         if (error)
2053                                 goto cleanup;
2054                 }
2055         }
2056
2057         if (old_ea_inode_size)
2058                 ext4_xattr_inode_free_quota(inode, old_ea_inode_size);
2059
2060         /* Update the inode. */
2061         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2062
2063         /* Drop the previous xattr block. */
2064         if (bs->bh && bs->bh != new_bh) {
2065                 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2066
2067                 ext4_xattr_release_block(handle, inode, bs->bh,
2068                                          &ea_inode_array,
2069                                          0 /* extra_credits */);
2070                 ext4_xattr_inode_array_free(ea_inode_array);
2071         }
2072         error = 0;
2073
2074 cleanup:
2075         if (ea_inode) {
2076                 int error2;
2077
2078                 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2079                 if (error2)
2080                         ext4_warning_inode(ea_inode, "dec ref error=%d",
2081                                            error2);
2082
2083                 /* If there was an error, revert the quota charge. */
2084                 if (error)
2085                         ext4_xattr_inode_free_quota(inode,
2086                                                     i_size_read(ea_inode));
2087                 iput(ea_inode);
2088         }
2089         if (ce)
2090                 mb_cache_entry_put(ea_block_cache, ce);
2091         brelse(new_bh);
2092         if (!(bs->bh && s->base == bs->bh->b_data))
2093                 kfree(s->base);
2094
2095         return error;
2096
2097 cleanup_dquot:
2098         dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2099         goto cleanup;
2100
2101 bad_block:
2102         EXT4_ERROR_INODE(inode, "bad block %llu",
2103                          EXT4_I(inode)->i_file_acl);
2104         goto cleanup;
2105
2106 #undef header
2107 }
2108
2109 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2110                           struct ext4_xattr_ibody_find *is)
2111 {
2112         struct ext4_xattr_ibody_header *header;
2113         struct ext4_inode *raw_inode;
2114         int error;
2115
2116         if (EXT4_I(inode)->i_extra_isize == 0)
2117                 return 0;
2118         raw_inode = ext4_raw_inode(&is->iloc);
2119         header = IHDR(inode, raw_inode);
2120         is->s.base = is->s.first = IFIRST(header);
2121         is->s.here = is->s.first;
2122         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2123         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2124                 error = xattr_check_inode(inode, header, is->s.end);
2125                 if (error)
2126                         return error;
2127                 /* Find the named attribute. */
2128                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
2129                                               i->name, 0);
2130                 if (error && error != -ENODATA)
2131                         return error;
2132                 is->s.not_found = error;
2133         }
2134         return 0;
2135 }
2136
2137 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2138                                 struct ext4_xattr_info *i,
2139                                 struct ext4_xattr_ibody_find *is)
2140 {
2141         struct ext4_xattr_ibody_header *header;
2142         struct ext4_xattr_search *s = &is->s;
2143         int error;
2144
2145         if (EXT4_I(inode)->i_extra_isize == 0)
2146                 return -ENOSPC;
2147         error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2148         if (error) {
2149                 if (error == -ENOSPC &&
2150                     ext4_has_inline_data(inode)) {
2151                         error = ext4_try_to_evict_inline_data(handle, inode,
2152                                         EXT4_XATTR_LEN(strlen(i->name) +
2153                                         EXT4_XATTR_SIZE(i->value_len)));
2154                         if (error)
2155                                 return error;
2156                         error = ext4_xattr_ibody_find(inode, i, is);
2157                         if (error)
2158                                 return error;
2159                         error = ext4_xattr_set_entry(i, s, handle, inode,
2160                                                      false /* is_block */);
2161                 }
2162                 if (error)
2163                         return error;
2164         }
2165         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2166         if (!IS_LAST_ENTRY(s->first)) {
2167                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2168                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2169         } else {
2170                 header->h_magic = cpu_to_le32(0);
2171                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2172         }
2173         return 0;
2174 }
2175
2176 static int ext4_xattr_ibody_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                 return error;
2189         header = IHDR(inode, ext4_raw_inode(&is->iloc));
2190         if (!IS_LAST_ENTRY(s->first)) {
2191                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2192                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2193         } else {
2194                 header->h_magic = cpu_to_le32(0);
2195                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2196         }
2197         return 0;
2198 }
2199
2200 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2201                                  struct ext4_xattr_info *i)
2202 {
2203         void *value;
2204
2205         /* When e_value_inum is set the value is stored externally. */
2206         if (s->here->e_value_inum)
2207                 return 0;
2208         if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2209                 return 0;
2210         value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2211         return !memcmp(value, i->value, i->value_len);
2212 }
2213
2214 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2215 {
2216         struct buffer_head *bh;
2217         int error;
2218
2219         if (!EXT4_I(inode)->i_file_acl)
2220                 return NULL;
2221         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2222         if (!bh)
2223                 return ERR_PTR(-EIO);
2224         error = ext4_xattr_check_block(inode, bh);
2225         if (error)
2226                 return ERR_PTR(error);
2227         return bh;
2228 }
2229
2230 /*
2231  * ext4_xattr_set_handle()
2232  *
2233  * Create, replace or remove an extended attribute for this inode.  Value
2234  * is NULL to remove an existing extended attribute, and non-NULL to
2235  * either replace an existing extended attribute, or create a new extended
2236  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2237  * specify that an extended attribute must exist and must not exist
2238  * previous to the call, respectively.
2239  *
2240  * Returns 0, or a negative error number on failure.
2241  */
2242 int
2243 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2244                       const char *name, const void *value, size_t value_len,
2245                       int flags)
2246 {
2247         struct ext4_xattr_info i = {
2248                 .name_index = name_index,
2249                 .name = name,
2250                 .value = value,
2251                 .value_len = value_len,
2252                 .in_inode = 0,
2253         };
2254         struct ext4_xattr_ibody_find is = {
2255                 .s = { .not_found = -ENODATA, },
2256         };
2257         struct ext4_xattr_block_find bs = {
2258                 .s = { .not_found = -ENODATA, },
2259         };
2260         int no_expand;
2261         int error;
2262
2263         if (!name)
2264                 return -EINVAL;
2265         if (strlen(name) > 255)
2266                 return -ERANGE;
2267
2268         ext4_write_lock_xattr(inode, &no_expand);
2269
2270         /* Check journal credits under write lock. */
2271         if (ext4_handle_valid(handle)) {
2272                 struct buffer_head *bh;
2273                 int credits;
2274
2275                 bh = ext4_xattr_get_block(inode);
2276                 if (IS_ERR(bh)) {
2277                         error = PTR_ERR(bh);
2278                         goto cleanup;
2279                 }
2280
2281                 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2282                                                    value_len,
2283                                                    flags & XATTR_CREATE);
2284                 brelse(bh);
2285
2286                 if (!ext4_handle_has_enough_credits(handle, credits)) {
2287                         error = -ENOSPC;
2288                         goto cleanup;
2289                 }
2290         }
2291
2292         error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2293         if (error)
2294                 goto cleanup;
2295
2296         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2297                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2298                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2299                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2300         }
2301
2302         error = ext4_xattr_ibody_find(inode, &i, &is);
2303         if (error)
2304                 goto cleanup;
2305         if (is.s.not_found)
2306                 error = ext4_xattr_block_find(inode, &i, &bs);
2307         if (error)
2308                 goto cleanup;
2309         if (is.s.not_found && bs.s.not_found) {
2310                 error = -ENODATA;
2311                 if (flags & XATTR_REPLACE)
2312                         goto cleanup;
2313                 error = 0;
2314                 if (!value)
2315                         goto cleanup;
2316         } else {
2317                 error = -EEXIST;
2318                 if (flags & XATTR_CREATE)
2319                         goto cleanup;
2320         }
2321
2322         if (!value) {
2323                 if (!is.s.not_found)
2324                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2325                 else if (!bs.s.not_found)
2326                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2327         } else {
2328                 error = 0;
2329                 /* Xattr value did not change? Save us some work and bail out */
2330                 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2331                         goto cleanup;
2332                 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2333                         goto cleanup;
2334
2335                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2336                     (EXT4_XATTR_SIZE(i.value_len) >
2337                         EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2338                         i.in_inode = 1;
2339 retry_inode:
2340                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2341                 if (!error && !bs.s.not_found) {
2342                         i.value = NULL;
2343                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2344                 } else if (error == -ENOSPC) {
2345                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2346                                 error = ext4_xattr_block_find(inode, &i, &bs);
2347                                 if (error)
2348                                         goto cleanup;
2349                         }
2350                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
2351                         if (!error && !is.s.not_found) {
2352                                 i.value = NULL;
2353                                 error = ext4_xattr_ibody_set(handle, inode, &i,
2354                                                              &is);
2355                         } else if (error == -ENOSPC) {
2356                                 /*
2357                                  * Xattr does not fit in the block, store at
2358                                  * external inode if possible.
2359                                  */
2360                                 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2361                                     !i.in_inode) {
2362                                         i.in_inode = 1;
2363                                         goto retry_inode;
2364                                 }
2365                         }
2366                 }
2367         }
2368         if (!error) {
2369                 ext4_xattr_update_super_block(handle, inode->i_sb);
2370                 inode->i_ctime = current_time(inode);
2371                 if (!value)
2372                         no_expand = 0;
2373                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2374                 /*
2375                  * The bh is consumed by ext4_mark_iloc_dirty, even with
2376                  * error != 0.
2377                  */
2378                 is.iloc.bh = NULL;
2379                 if (IS_SYNC(inode))
2380                         ext4_handle_sync(handle);
2381         }
2382
2383 cleanup:
2384         brelse(is.iloc.bh);
2385         brelse(bs.bh);
2386         ext4_write_unlock_xattr(inode, &no_expand);
2387         return error;
2388 }
2389
2390 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2391                            bool is_create, int *credits)
2392 {
2393         struct buffer_head *bh;
2394         int err;
2395
2396         *credits = 0;
2397
2398         if (!EXT4_SB(inode->i_sb)->s_journal)
2399                 return 0;
2400
2401         down_read(&EXT4_I(inode)->xattr_sem);
2402
2403         bh = ext4_xattr_get_block(inode);
2404         if (IS_ERR(bh)) {
2405                 err = PTR_ERR(bh);
2406         } else {
2407                 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2408                                                     value_len, is_create);
2409                 brelse(bh);
2410                 err = 0;
2411         }
2412
2413         up_read(&EXT4_I(inode)->xattr_sem);
2414         return err;
2415 }
2416
2417 /*
2418  * ext4_xattr_set()
2419  *
2420  * Like ext4_xattr_set_handle, but start from an inode. This extended
2421  * attribute modification is a filesystem transaction by itself.
2422  *
2423  * Returns 0, or a negative error number on failure.
2424  */
2425 int
2426 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2427                const void *value, size_t value_len, int flags)
2428 {
2429         handle_t *handle;
2430         struct super_block *sb = inode->i_sb;
2431         int error, retries = 0;
2432         int credits;
2433
2434         error = dquot_initialize(inode);
2435         if (error)
2436                 return error;
2437
2438 retry:
2439         error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2440                                        &credits);
2441         if (error)
2442                 return error;
2443
2444         handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2445         if (IS_ERR(handle)) {
2446                 error = PTR_ERR(handle);
2447         } else {
2448                 int error2;
2449
2450                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2451                                               value, value_len, flags);
2452                 error2 = ext4_journal_stop(handle);
2453                 if (error == -ENOSPC &&
2454                     ext4_should_retry_alloc(sb, &retries))
2455                         goto retry;
2456                 if (error == 0)
2457                         error = error2;
2458         }
2459
2460         return error;
2461 }
2462
2463 /*
2464  * Shift the EA entries in the inode to create space for the increased
2465  * i_extra_isize.
2466  */
2467 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2468                                      int value_offs_shift, void *to,
2469                                      void *from, size_t n)
2470 {
2471         struct ext4_xattr_entry *last = entry;
2472         int new_offs;
2473
2474         /* We always shift xattr headers further thus offsets get lower */
2475         BUG_ON(value_offs_shift > 0);
2476
2477         /* Adjust the value offsets of the entries */
2478         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2479                 if (!last->e_value_inum && last->e_value_size) {
2480                         new_offs = le16_to_cpu(last->e_value_offs) +
2481                                                         value_offs_shift;
2482                         last->e_value_offs = cpu_to_le16(new_offs);
2483                 }
2484         }
2485         /* Shift the entries by n bytes */
2486         memmove(to, from, n);
2487 }
2488
2489 /*
2490  * Move xattr pointed to by 'entry' from inode into external xattr block
2491  */
2492 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2493                                     struct ext4_inode *raw_inode,
2494                                     struct ext4_xattr_entry *entry)
2495 {
2496         struct ext4_xattr_ibody_find *is = NULL;
2497         struct ext4_xattr_block_find *bs = NULL;
2498         char *buffer = NULL, *b_entry_name = NULL;
2499         size_t value_size = le32_to_cpu(entry->e_value_size);
2500         struct ext4_xattr_info i = {
2501                 .value = NULL,
2502                 .value_len = 0,
2503                 .name_index = entry->e_name_index,
2504                 .in_inode = !!entry->e_value_inum,
2505         };
2506         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2507         int error;
2508
2509         is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2510         bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2511         buffer = kmalloc(value_size, GFP_NOFS);
2512         b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2513         if (!is || !bs || !buffer || !b_entry_name) {
2514                 error = -ENOMEM;
2515                 goto out;
2516         }
2517
2518         is->s.not_found = -ENODATA;
2519         bs->s.not_found = -ENODATA;
2520         is->iloc.bh = NULL;
2521         bs->bh = NULL;
2522
2523         /* Save the entry name and the entry value */
2524         if (entry->e_value_inum) {
2525                 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2526                 if (error)
2527                         goto out;
2528         } else {
2529                 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2530                 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2531         }
2532
2533         memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2534         b_entry_name[entry->e_name_len] = '\0';
2535         i.name = b_entry_name;
2536
2537         error = ext4_get_inode_loc(inode, &is->iloc);
2538         if (error)
2539                 goto out;
2540
2541         error = ext4_xattr_ibody_find(inode, &i, is);
2542         if (error)
2543                 goto out;
2544
2545         /* Remove the chosen entry from the inode */
2546         error = ext4_xattr_ibody_set(handle, inode, &i, is);
2547         if (error)
2548                 goto out;
2549
2550         i.value = buffer;
2551         i.value_len = value_size;
2552         error = ext4_xattr_block_find(inode, &i, bs);
2553         if (error)
2554                 goto out;
2555
2556         /* Add entry which was removed from the inode into the block */
2557         error = ext4_xattr_block_set(handle, inode, &i, bs);
2558         if (error)
2559                 goto out;
2560         error = 0;
2561 out:
2562         kfree(b_entry_name);
2563         kfree(buffer);
2564         if (is)
2565                 brelse(is->iloc.bh);
2566         kfree(is);
2567         kfree(bs);
2568
2569         return error;
2570 }
2571
2572 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2573                                        struct ext4_inode *raw_inode,
2574                                        int isize_diff, size_t ifree,
2575                                        size_t bfree, int *total_ino)
2576 {
2577         struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2578         struct ext4_xattr_entry *small_entry;
2579         struct ext4_xattr_entry *entry;
2580         struct ext4_xattr_entry *last;
2581         unsigned int entry_size;        /* EA entry size */
2582         unsigned int total_size;        /* EA entry size + value size */
2583         unsigned int min_total_size;
2584         int error;
2585
2586         while (isize_diff > ifree) {
2587                 entry = NULL;
2588                 small_entry = NULL;
2589                 min_total_size = ~0U;
2590                 last = IFIRST(header);
2591                 /* Find the entry best suited to be pushed into EA block */
2592                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2593                         total_size = EXT4_XATTR_LEN(last->e_name_len);
2594                         if (!last->e_value_inum)
2595                                 total_size += EXT4_XATTR_SIZE(
2596                                                le32_to_cpu(last->e_value_size));
2597                         if (total_size <= bfree &&
2598                             total_size < min_total_size) {
2599                                 if (total_size + ifree < isize_diff) {
2600                                         small_entry = last;
2601                                 } else {
2602                                         entry = last;
2603                                         min_total_size = total_size;
2604                                 }
2605                         }
2606                 }
2607
2608                 if (entry == NULL) {
2609                         if (small_entry == NULL)
2610                                 return -ENOSPC;
2611                         entry = small_entry;
2612                 }
2613
2614                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2615                 total_size = entry_size;
2616                 if (!entry->e_value_inum)
2617                         total_size += EXT4_XATTR_SIZE(
2618                                               le32_to_cpu(entry->e_value_size));
2619                 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2620                                                  entry);
2621                 if (error)
2622                         return error;
2623
2624                 *total_ino -= entry_size;
2625                 ifree += total_size;
2626                 bfree -= total_size;
2627         }
2628
2629         return 0;
2630 }
2631
2632 /*
2633  * Expand an inode by new_extra_isize bytes when EAs are present.
2634  * Returns 0 on success or negative error number on failure.
2635  */
2636 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2637                                struct ext4_inode *raw_inode, handle_t *handle)
2638 {
2639         struct ext4_xattr_ibody_header *header;
2640         struct buffer_head *bh;
2641         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2642         static unsigned int mnt_count;
2643         size_t min_offs;
2644         size_t ifree, bfree;
2645         int total_ino;
2646         void *base, *end;
2647         int error = 0, tried_min_extra_isize = 0;
2648         int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2649         int isize_diff; /* How much do we need to grow i_extra_isize */
2650
2651 retry:
2652         isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2653         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2654                 return 0;
2655
2656         header = IHDR(inode, raw_inode);
2657
2658         /*
2659          * Check if enough free space is available in the inode to shift the
2660          * entries ahead by new_extra_isize.
2661          */
2662
2663         base = IFIRST(header);
2664         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2665         min_offs = end - base;
2666         total_ino = sizeof(struct ext4_xattr_ibody_header);
2667
2668         error = xattr_check_inode(inode, header, end);
2669         if (error)
2670                 goto cleanup;
2671
2672         ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2673         if (ifree >= isize_diff)
2674                 goto shift;
2675
2676         /*
2677          * Enough free space isn't available in the inode, check if
2678          * EA block can hold new_extra_isize bytes.
2679          */
2680         if (EXT4_I(inode)->i_file_acl) {
2681                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2682                 error = -EIO;
2683                 if (!bh)
2684                         goto cleanup;
2685                 if (ext4_xattr_check_block(inode, bh)) {
2686                         EXT4_ERROR_INODE(inode, "bad block %llu",
2687                                          EXT4_I(inode)->i_file_acl);
2688                         error = -EFSCORRUPTED;
2689                         brelse(bh);
2690                         goto cleanup;
2691                 }
2692                 base = BHDR(bh);
2693                 end = bh->b_data + bh->b_size;
2694                 min_offs = end - base;
2695                 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2696                                               NULL);
2697                 brelse(bh);
2698                 if (bfree + ifree < isize_diff) {
2699                         if (!tried_min_extra_isize && s_min_extra_isize) {
2700                                 tried_min_extra_isize++;
2701                                 new_extra_isize = s_min_extra_isize;
2702                                 goto retry;
2703                         }
2704                         error = -ENOSPC;
2705                         goto cleanup;
2706                 }
2707         } else {
2708                 bfree = inode->i_sb->s_blocksize;
2709         }
2710
2711         error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2712                                             isize_diff, ifree, bfree,
2713                                             &total_ino);
2714         if (error) {
2715                 if (error == -ENOSPC && !tried_min_extra_isize &&
2716                     s_min_extra_isize) {
2717                         tried_min_extra_isize++;
2718                         new_extra_isize = s_min_extra_isize;
2719                         goto retry;
2720                 }
2721                 goto cleanup;
2722         }
2723 shift:
2724         /* Adjust the offsets and shift the remaining entries ahead */
2725         ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2726                         - new_extra_isize, (void *)raw_inode +
2727                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2728                         (void *)header, total_ino);
2729         EXT4_I(inode)->i_extra_isize = new_extra_isize;
2730
2731 cleanup:
2732         if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2733                 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2734                              inode->i_ino);
2735                 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2736         }
2737         return error;
2738 }
2739
2740 #define EIA_INCR 16 /* must be 2^n */
2741 #define EIA_MASK (EIA_INCR - 1)
2742
2743 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2744  * If @ea_inode_array is new or full it will be grown and the old
2745  * contents copied over.
2746  */
2747 static int
2748 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2749                         struct inode *inode)
2750 {
2751         if (*ea_inode_array == NULL) {
2752                 /*
2753                  * Start with 15 inodes, so it fits into a power-of-two size.
2754                  * If *ea_inode_array is NULL, this is essentially offsetof()
2755                  */
2756                 (*ea_inode_array) =
2757                         kmalloc(offsetof(struct ext4_xattr_inode_array,
2758                                          inodes[EIA_MASK]),
2759                                 GFP_NOFS);
2760                 if (*ea_inode_array == NULL)
2761                         return -ENOMEM;
2762                 (*ea_inode_array)->count = 0;
2763         } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2764                 /* expand the array once all 15 + n * 16 slots are full */
2765                 struct ext4_xattr_inode_array *new_array = NULL;
2766                 int count = (*ea_inode_array)->count;
2767
2768                 /* if new_array is NULL, this is essentially offsetof() */
2769                 new_array = kmalloc(
2770                                 offsetof(struct ext4_xattr_inode_array,
2771                                          inodes[count + EIA_INCR]),
2772                                 GFP_NOFS);
2773                 if (new_array == NULL)
2774                         return -ENOMEM;
2775                 memcpy(new_array, *ea_inode_array,
2776                        offsetof(struct ext4_xattr_inode_array, inodes[count]));
2777                 kfree(*ea_inode_array);
2778                 *ea_inode_array = new_array;
2779         }
2780         (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2781         return 0;
2782 }
2783
2784 /*
2785  * ext4_xattr_delete_inode()
2786  *
2787  * Free extended attribute resources associated with this inode. Traverse
2788  * all entries and decrement reference on any xattr inodes associated with this
2789  * inode. This is called immediately before an inode is freed. We have exclusive
2790  * access to the inode. If an orphan inode is deleted it will also release its
2791  * references on xattr block and xattr inodes.
2792  */
2793 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2794                             struct ext4_xattr_inode_array **ea_inode_array,
2795                             int extra_credits)
2796 {
2797         struct buffer_head *bh = NULL;
2798         struct ext4_xattr_ibody_header *header;
2799         struct ext4_iloc iloc = { .bh = NULL };
2800         struct ext4_xattr_entry *entry;
2801         int error;
2802
2803         error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
2804                                           NULL /* bh */,
2805                                           false /* dirty */,
2806                                           false /* block_csum */);
2807         if (error) {
2808                 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2809                 goto cleanup;
2810         }
2811
2812         if (ext4_has_feature_ea_inode(inode->i_sb) &&
2813             ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2814
2815                 error = ext4_get_inode_loc(inode, &iloc);
2816                 if (error) {
2817                         EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2818                         goto cleanup;
2819                 }
2820
2821                 error = ext4_journal_get_write_access(handle, iloc.bh);
2822                 if (error) {
2823                         EXT4_ERROR_INODE(inode, "write access (error %d)",
2824                                          error);
2825                         goto cleanup;
2826                 }
2827
2828                 header = IHDR(inode, ext4_raw_inode(&iloc));
2829                 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2830                         ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2831                                                      IFIRST(header),
2832                                                      false /* block_csum */,
2833                                                      ea_inode_array,
2834                                                      extra_credits,
2835                                                      false /* skip_quota */);
2836         }
2837
2838         if (EXT4_I(inode)->i_file_acl) {
2839                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2840                 if (!bh) {
2841                         EXT4_ERROR_INODE(inode, "block %llu read error",
2842                                          EXT4_I(inode)->i_file_acl);
2843                         error = -EIO;
2844                         goto cleanup;
2845                 }
2846                 error = ext4_xattr_check_block(inode, bh);
2847                 if (error) {
2848                         EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
2849                                          EXT4_I(inode)->i_file_acl, error);
2850                         goto cleanup;
2851                 }
2852
2853                 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2854                         for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2855                              entry = EXT4_XATTR_NEXT(entry))
2856                                 if (entry->e_value_inum)
2857                                         ext4_xattr_inode_free_quota(inode,
2858                                               le32_to_cpu(entry->e_value_size));
2859
2860                 }
2861
2862                 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2863                                          extra_credits);
2864                 /*
2865                  * Update i_file_acl value in the same transaction that releases
2866                  * block.
2867                  */
2868                 EXT4_I(inode)->i_file_acl = 0;
2869                 error = ext4_mark_inode_dirty(handle, inode);
2870                 if (error) {
2871                         EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2872                                          error);
2873                         goto cleanup;
2874                 }
2875         }
2876         error = 0;
2877 cleanup:
2878         brelse(iloc.bh);
2879         brelse(bh);
2880         return error;
2881 }
2882
2883 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2884 {
2885         int idx;
2886
2887         if (ea_inode_array == NULL)
2888                 return;
2889
2890         for (idx = 0; idx < ea_inode_array->count; ++idx)
2891                 iput(ea_inode_array->inodes[idx]);
2892         kfree(ea_inode_array);
2893 }
2894
2895 /*
2896  * ext4_xattr_block_cache_insert()
2897  *
2898  * Create a new entry in the extended attribute block cache, and insert
2899  * it unless such an entry is already in the cache.
2900  *
2901  * Returns 0, or a negative error number on failure.
2902  */
2903 static void
2904 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2905                               struct buffer_head *bh)
2906 {
2907         struct ext4_xattr_header *header = BHDR(bh);
2908         __u32 hash = le32_to_cpu(header->h_hash);
2909         int reusable = le32_to_cpu(header->h_refcount) <
2910                        EXT4_XATTR_REFCOUNT_MAX;
2911         int error;
2912
2913         if (!ea_block_cache)
2914                 return;
2915         error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2916                                       bh->b_blocknr, reusable);
2917         if (error) {
2918                 if (error == -EBUSY)
2919                         ea_bdebug(bh, "already in cache");
2920         } else
2921                 ea_bdebug(bh, "inserting [%x]", (int)hash);
2922 }
2923
2924 /*
2925  * ext4_xattr_cmp()
2926  *
2927  * Compare two extended attribute blocks for equality.
2928  *
2929  * Returns 0 if the blocks are equal, 1 if they differ, and
2930  * a negative error number on errors.
2931  */
2932 static int
2933 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2934                struct ext4_xattr_header *header2)
2935 {
2936         struct ext4_xattr_entry *entry1, *entry2;
2937
2938         entry1 = ENTRY(header1+1);
2939         entry2 = ENTRY(header2+1);
2940         while (!IS_LAST_ENTRY(entry1)) {
2941                 if (IS_LAST_ENTRY(entry2))
2942                         return 1;
2943                 if (entry1->e_hash != entry2->e_hash ||
2944                     entry1->e_name_index != entry2->e_name_index ||
2945                     entry1->e_name_len != entry2->e_name_len ||
2946                     entry1->e_value_size != entry2->e_value_size ||
2947                     entry1->e_value_inum != entry2->e_value_inum ||
2948                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2949                         return 1;
2950                 if (!entry1->e_value_inum &&
2951                     memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
2952                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
2953                            le32_to_cpu(entry1->e_value_size)))
2954                         return 1;
2955
2956                 entry1 = EXT4_XATTR_NEXT(entry1);
2957                 entry2 = EXT4_XATTR_NEXT(entry2);
2958         }
2959         if (!IS_LAST_ENTRY(entry2))
2960                 return 1;
2961         return 0;
2962 }
2963
2964 /*
2965  * ext4_xattr_block_cache_find()
2966  *
2967  * Find an identical extended attribute block.
2968  *
2969  * Returns a pointer to the block found, or NULL if such a block was
2970  * not found or an error occurred.
2971  */
2972 static struct buffer_head *
2973 ext4_xattr_block_cache_find(struct inode *inode,
2974                             struct ext4_xattr_header *header,
2975                             struct mb_cache_entry **pce)
2976 {
2977         __u32 hash = le32_to_cpu(header->h_hash);
2978         struct mb_cache_entry *ce;
2979         struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
2980
2981         if (!ea_block_cache)
2982                 return NULL;
2983         if (!header->h_hash)
2984                 return NULL;  /* never share */
2985         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
2986         ce = mb_cache_entry_find_first(ea_block_cache, hash);
2987         while (ce) {
2988                 struct buffer_head *bh;
2989
2990                 bh = sb_bread(inode->i_sb, ce->e_value);
2991                 if (!bh) {
2992                         EXT4_ERROR_INODE(inode, "block %lu read error",
2993                                          (unsigned long)ce->e_value);
2994                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
2995                         *pce = ce;
2996                         return bh;
2997                 }
2998                 brelse(bh);
2999                 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3000         }
3001         return NULL;
3002 }
3003
3004 #define NAME_HASH_SHIFT 5
3005 #define VALUE_HASH_SHIFT 16
3006
3007 /*
3008  * ext4_xattr_hash_entry()
3009  *
3010  * Compute the hash of an extended attribute.
3011  */
3012 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3013                                     size_t value_count)
3014 {
3015         __u32 hash = 0;
3016
3017         while (name_len--) {
3018                 hash = (hash << NAME_HASH_SHIFT) ^
3019                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3020                        *name++;
3021         }
3022         while (value_count--) {
3023                 hash = (hash << VALUE_HASH_SHIFT) ^
3024                        (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3025                        le32_to_cpu(*value++);
3026         }
3027         return cpu_to_le32(hash);
3028 }
3029
3030 #undef NAME_HASH_SHIFT
3031 #undef VALUE_HASH_SHIFT
3032
3033 #define BLOCK_HASH_SHIFT 16
3034
3035 /*
3036  * ext4_xattr_rehash()
3037  *
3038  * Re-compute the extended attribute hash value after an entry has changed.
3039  */
3040 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3041 {
3042         struct ext4_xattr_entry *here;
3043         __u32 hash = 0;
3044
3045         here = ENTRY(header+1);
3046         while (!IS_LAST_ENTRY(here)) {
3047                 if (!here->e_hash) {
3048                         /* Block is not shared if an entry's hash value == 0 */
3049                         hash = 0;
3050                         break;
3051                 }
3052                 hash = (hash << BLOCK_HASH_SHIFT) ^
3053                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3054                        le32_to_cpu(here->e_hash);
3055                 here = EXT4_XATTR_NEXT(here);
3056         }
3057         header->h_hash = cpu_to_le32(hash);
3058 }
3059
3060 #undef BLOCK_HASH_SHIFT
3061
3062 #define HASH_BUCKET_BITS        10
3063
3064 struct mb_cache *
3065 ext4_xattr_create_cache(void)
3066 {
3067         return mb_cache_create(HASH_BUCKET_BITS);
3068 }
3069
3070 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3071 {
3072         if (cache)
3073                 mb_cache_destroy(cache);
3074 }
3075