Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/ext2/xattr.c |
| 3 | * |
| 4 | * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de> |
| 5 | * |
| 6 | * Fix by Harrison Xing <harrison@mountainviewdata.com>. |
| 7 | * Extended attributes for symlinks and special files added per |
| 8 | * suggestion of Luka Renko <luka.renko@hermes.si>. |
| 9 | * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>, |
| 10 | * Red Hat Inc. |
| 11 | * |
| 12 | */ |
| 13 | |
| 14 | /* |
| 15 | * Extended attributes are stored on disk blocks allocated outside of |
| 16 | * any inode. The i_file_acl field is then made to point to this allocated |
| 17 | * block. If all extended attributes of an inode are identical, these |
| 18 | * inodes may share the same extended attribute block. Such situations |
| 19 | * are automatically detected by keeping a cache of recent attribute block |
| 20 | * numbers and hashes over the block's contents in memory. |
| 21 | * |
| 22 | * |
| 23 | * Extended attribute block layout: |
| 24 | * |
| 25 | * +------------------+ |
| 26 | * | header | |
| 27 | * | entry 1 | | |
| 28 | * | entry 2 | | growing downwards |
| 29 | * | entry 3 | v |
| 30 | * | four null bytes | |
| 31 | * | . . . | |
| 32 | * | value 1 | ^ |
| 33 | * | value 3 | | growing upwards |
| 34 | * | value 2 | | |
| 35 | * +------------------+ |
| 36 | * |
| 37 | * The block header is followed by multiple entry descriptors. These entry |
| 38 | * descriptors are variable in size, and alligned to EXT2_XATTR_PAD |
| 39 | * byte boundaries. The entry descriptors are sorted by attribute name, |
| 40 | * so that two extended attribute blocks can be compared efficiently. |
| 41 | * |
| 42 | * Attribute values are aligned to the end of the block, stored in |
| 43 | * no specific order. They are also padded to EXT2_XATTR_PAD byte |
| 44 | * boundaries. No additional gaps are left between them. |
| 45 | * |
| 46 | * Locking strategy |
| 47 | * ---------------- |
| 48 | * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem. |
| 49 | * EA blocks are only changed if they are exclusive to an inode, so |
| 50 | * holding xattr_sem also means that nothing but the EA block's reference |
| 51 | * count will change. Multiple writers to an EA block are synchronized |
| 52 | * by the bh lock. No more than a single bh lock is held at any time |
| 53 | * to avoid deadlocks. |
| 54 | */ |
| 55 | |
| 56 | #include <linux/buffer_head.h> |
| 57 | #include <linux/module.h> |
| 58 | #include <linux/init.h> |
| 59 | #include <linux/slab.h> |
| 60 | #include <linux/mbcache.h> |
| 61 | #include <linux/quotaops.h> |
| 62 | #include <linux/rwsem.h> |
| 63 | #include "ext2.h" |
| 64 | #include "xattr.h" |
| 65 | #include "acl.h" |
| 66 | |
| 67 | #define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data)) |
| 68 | #define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr)) |
| 69 | #define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1) |
| 70 | #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) |
| 71 | |
| 72 | #ifdef EXT2_XATTR_DEBUG |
| 73 | # define ea_idebug(inode, f...) do { \ |
| 74 | printk(KERN_DEBUG "inode %s:%ld: ", \ |
| 75 | inode->i_sb->s_id, inode->i_ino); \ |
| 76 | printk(f); \ |
| 77 | printk("\n"); \ |
| 78 | } while (0) |
| 79 | # define ea_bdebug(bh, f...) do { \ |
| 80 | char b[BDEVNAME_SIZE]; \ |
| 81 | printk(KERN_DEBUG "block %s:%lu: ", \ |
| 82 | bdevname(bh->b_bdev, b), \ |
| 83 | (unsigned long) bh->b_blocknr); \ |
| 84 | printk(f); \ |
| 85 | printk("\n"); \ |
| 86 | } while (0) |
| 87 | #else |
| 88 | # define ea_idebug(f...) |
| 89 | # define ea_bdebug(f...) |
| 90 | #endif |
| 91 | |
| 92 | static int ext2_xattr_set2(struct inode *, struct buffer_head *, |
| 93 | struct ext2_xattr_header *); |
| 94 | |
| 95 | static int ext2_xattr_cache_insert(struct buffer_head *); |
| 96 | static struct buffer_head *ext2_xattr_cache_find(struct inode *, |
| 97 | struct ext2_xattr_header *); |
| 98 | static void ext2_xattr_rehash(struct ext2_xattr_header *, |
| 99 | struct ext2_xattr_entry *); |
| 100 | |
| 101 | static struct mb_cache *ext2_xattr_cache; |
| 102 | |
| 103 | static struct xattr_handler *ext2_xattr_handler_map[] = { |
| 104 | [EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler, |
| 105 | #ifdef CONFIG_EXT2_FS_POSIX_ACL |
| 106 | [EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext2_xattr_acl_access_handler, |
| 107 | [EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext2_xattr_acl_default_handler, |
| 108 | #endif |
| 109 | [EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler, |
| 110 | #ifdef CONFIG_EXT2_FS_SECURITY |
| 111 | [EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler, |
| 112 | #endif |
| 113 | }; |
| 114 | |
| 115 | struct xattr_handler *ext2_xattr_handlers[] = { |
| 116 | &ext2_xattr_user_handler, |
| 117 | &ext2_xattr_trusted_handler, |
| 118 | #ifdef CONFIG_EXT2_FS_POSIX_ACL |
| 119 | &ext2_xattr_acl_access_handler, |
| 120 | &ext2_xattr_acl_default_handler, |
| 121 | #endif |
| 122 | #ifdef CONFIG_EXT2_FS_SECURITY |
| 123 | &ext2_xattr_security_handler, |
| 124 | #endif |
| 125 | NULL |
| 126 | }; |
| 127 | |
| 128 | static inline struct xattr_handler * |
| 129 | ext2_xattr_handler(int name_index) |
| 130 | { |
| 131 | struct xattr_handler *handler = NULL; |
| 132 | |
| 133 | if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map)) |
| 134 | handler = ext2_xattr_handler_map[name_index]; |
| 135 | return handler; |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * ext2_xattr_get() |
| 140 | * |
| 141 | * Copy an extended attribute into the buffer |
| 142 | * provided, or compute the buffer size required. |
| 143 | * Buffer is NULL to compute the size of the buffer required. |
| 144 | * |
| 145 | * Returns a negative error number on failure, or the number of bytes |
| 146 | * used / required on success. |
| 147 | */ |
| 148 | int |
| 149 | ext2_xattr_get(struct inode *inode, int name_index, const char *name, |
| 150 | void *buffer, size_t buffer_size) |
| 151 | { |
| 152 | struct buffer_head *bh = NULL; |
| 153 | struct ext2_xattr_entry *entry; |
| 154 | size_t name_len, size; |
| 155 | char *end; |
| 156 | int error; |
| 157 | |
| 158 | ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", |
| 159 | name_index, name, buffer, (long)buffer_size); |
| 160 | |
| 161 | if (name == NULL) |
| 162 | return -EINVAL; |
| 163 | down_read(&EXT2_I(inode)->xattr_sem); |
| 164 | error = -ENODATA; |
| 165 | if (!EXT2_I(inode)->i_file_acl) |
| 166 | goto cleanup; |
| 167 | ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); |
| 168 | bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); |
| 169 | error = -EIO; |
| 170 | if (!bh) |
| 171 | goto cleanup; |
| 172 | ea_bdebug(bh, "b_count=%d, refcount=%d", |
| 173 | atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); |
| 174 | end = bh->b_data + bh->b_size; |
| 175 | if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| 176 | HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| 177 | bad_block: ext2_error(inode->i_sb, "ext2_xattr_get", |
| 178 | "inode %ld: bad block %d", inode->i_ino, |
| 179 | EXT2_I(inode)->i_file_acl); |
| 180 | error = -EIO; |
| 181 | goto cleanup; |
| 182 | } |
| 183 | /* find named attribute */ |
| 184 | name_len = strlen(name); |
| 185 | |
| 186 | error = -ERANGE; |
| 187 | if (name_len > 255) |
| 188 | goto cleanup; |
| 189 | entry = FIRST_ENTRY(bh); |
| 190 | while (!IS_LAST_ENTRY(entry)) { |
| 191 | struct ext2_xattr_entry *next = |
| 192 | EXT2_XATTR_NEXT(entry); |
| 193 | if ((char *)next >= end) |
| 194 | goto bad_block; |
| 195 | if (name_index == entry->e_name_index && |
| 196 | name_len == entry->e_name_len && |
| 197 | memcmp(name, entry->e_name, name_len) == 0) |
| 198 | goto found; |
| 199 | entry = next; |
| 200 | } |
| 201 | /* Check the remaining name entries */ |
| 202 | while (!IS_LAST_ENTRY(entry)) { |
| 203 | struct ext2_xattr_entry *next = |
| 204 | EXT2_XATTR_NEXT(entry); |
| 205 | if ((char *)next >= end) |
| 206 | goto bad_block; |
| 207 | entry = next; |
| 208 | } |
| 209 | if (ext2_xattr_cache_insert(bh)) |
| 210 | ea_idebug(inode, "cache insert failed"); |
| 211 | error = -ENODATA; |
| 212 | goto cleanup; |
| 213 | found: |
| 214 | /* check the buffer size */ |
| 215 | if (entry->e_value_block != 0) |
| 216 | goto bad_block; |
| 217 | size = le32_to_cpu(entry->e_value_size); |
| 218 | if (size > inode->i_sb->s_blocksize || |
| 219 | le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize) |
| 220 | goto bad_block; |
| 221 | |
| 222 | if (ext2_xattr_cache_insert(bh)) |
| 223 | ea_idebug(inode, "cache insert failed"); |
| 224 | if (buffer) { |
| 225 | error = -ERANGE; |
| 226 | if (size > buffer_size) |
| 227 | goto cleanup; |
| 228 | /* return value of attribute */ |
| 229 | memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), |
| 230 | size); |
| 231 | } |
| 232 | error = size; |
| 233 | |
| 234 | cleanup: |
| 235 | brelse(bh); |
| 236 | up_read(&EXT2_I(inode)->xattr_sem); |
| 237 | |
| 238 | return error; |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * ext2_xattr_list() |
| 243 | * |
| 244 | * Copy a list of attribute names into the buffer |
| 245 | * provided, or compute the buffer size required. |
| 246 | * Buffer is NULL to compute the size of the buffer required. |
| 247 | * |
| 248 | * Returns a negative error number on failure, or the number of bytes |
| 249 | * used / required on success. |
| 250 | */ |
| 251 | static int |
| 252 | ext2_xattr_list(struct inode *inode, char *buffer, size_t buffer_size) |
| 253 | { |
| 254 | struct buffer_head *bh = NULL; |
| 255 | struct ext2_xattr_entry *entry; |
| 256 | char *end; |
| 257 | size_t rest = buffer_size; |
| 258 | int error; |
| 259 | |
| 260 | ea_idebug(inode, "buffer=%p, buffer_size=%ld", |
| 261 | buffer, (long)buffer_size); |
| 262 | |
| 263 | down_read(&EXT2_I(inode)->xattr_sem); |
| 264 | error = 0; |
| 265 | if (!EXT2_I(inode)->i_file_acl) |
| 266 | goto cleanup; |
| 267 | ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); |
| 268 | bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); |
| 269 | error = -EIO; |
| 270 | if (!bh) |
| 271 | goto cleanup; |
| 272 | ea_bdebug(bh, "b_count=%d, refcount=%d", |
| 273 | atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); |
| 274 | end = bh->b_data + bh->b_size; |
| 275 | if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| 276 | HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| 277 | bad_block: ext2_error(inode->i_sb, "ext2_xattr_list", |
| 278 | "inode %ld: bad block %d", inode->i_ino, |
| 279 | EXT2_I(inode)->i_file_acl); |
| 280 | error = -EIO; |
| 281 | goto cleanup; |
| 282 | } |
| 283 | |
| 284 | /* check the on-disk data structure */ |
| 285 | entry = FIRST_ENTRY(bh); |
| 286 | while (!IS_LAST_ENTRY(entry)) { |
| 287 | struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry); |
| 288 | |
| 289 | if ((char *)next >= end) |
| 290 | goto bad_block; |
| 291 | entry = next; |
| 292 | } |
| 293 | if (ext2_xattr_cache_insert(bh)) |
| 294 | ea_idebug(inode, "cache insert failed"); |
| 295 | |
| 296 | /* list the attribute names */ |
| 297 | for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry); |
| 298 | entry = EXT2_XATTR_NEXT(entry)) { |
| 299 | struct xattr_handler *handler = |
| 300 | ext2_xattr_handler(entry->e_name_index); |
| 301 | |
| 302 | if (handler) { |
| 303 | size_t size = handler->list(inode, buffer, rest, |
| 304 | entry->e_name, |
| 305 | entry->e_name_len); |
| 306 | if (buffer) { |
| 307 | if (size > rest) { |
| 308 | error = -ERANGE; |
| 309 | goto cleanup; |
| 310 | } |
| 311 | buffer += size; |
| 312 | } |
| 313 | rest -= size; |
| 314 | } |
| 315 | } |
| 316 | error = buffer_size - rest; /* total size */ |
| 317 | |
| 318 | cleanup: |
| 319 | brelse(bh); |
| 320 | up_read(&EXT2_I(inode)->xattr_sem); |
| 321 | |
| 322 | return error; |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * Inode operation listxattr() |
| 327 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 328 | * dentry->d_inode->i_mutex: don't care |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | */ |
| 330 | ssize_t |
| 331 | ext2_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| 332 | { |
| 333 | return ext2_xattr_list(dentry->d_inode, buffer, size); |
| 334 | } |
| 335 | |
| 336 | /* |
| 337 | * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is |
| 338 | * not set, set it. |
| 339 | */ |
| 340 | static void ext2_xattr_update_super_block(struct super_block *sb) |
| 341 | { |
| 342 | if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR)) |
| 343 | return; |
| 344 | |
Andreas Gruenbacher | ed2908f | 2006-12-06 20:36:16 -0800 | [diff] [blame] | 345 | EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | sb->s_dirt = 1; |
| 347 | mark_buffer_dirty(EXT2_SB(sb)->s_sbh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | } |
| 349 | |
| 350 | /* |
| 351 | * ext2_xattr_set() |
| 352 | * |
| 353 | * Create, replace or remove an extended attribute for this inode. Buffer |
| 354 | * is NULL to remove an existing extended attribute, and non-NULL to |
| 355 | * either replace an existing extended attribute, or create a new extended |
| 356 | * attribute. The flags XATTR_REPLACE and XATTR_CREATE |
| 357 | * specify that an extended attribute must exist and must not exist |
| 358 | * previous to the call, respectively. |
| 359 | * |
| 360 | * Returns 0, or a negative error number on failure. |
| 361 | */ |
| 362 | int |
| 363 | ext2_xattr_set(struct inode *inode, int name_index, const char *name, |
| 364 | const void *value, size_t value_len, int flags) |
| 365 | { |
| 366 | struct super_block *sb = inode->i_sb; |
| 367 | struct buffer_head *bh = NULL; |
| 368 | struct ext2_xattr_header *header = NULL; |
| 369 | struct ext2_xattr_entry *here, *last; |
| 370 | size_t name_len, free, min_offs = sb->s_blocksize; |
| 371 | int not_found = 1, error; |
| 372 | char *end; |
| 373 | |
| 374 | /* |
| 375 | * header -- Points either into bh, or to a temporarily |
| 376 | * allocated buffer. |
| 377 | * here -- The named entry found, or the place for inserting, within |
| 378 | * the block pointed to by header. |
| 379 | * last -- Points right after the last named entry within the block |
| 380 | * pointed to by header. |
| 381 | * min_offs -- The offset of the first value (values are aligned |
| 382 | * towards the end of the block). |
| 383 | * end -- Points right after the block pointed to by header. |
| 384 | */ |
| 385 | |
| 386 | ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", |
| 387 | name_index, name, value, (long)value_len); |
| 388 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | if (value == NULL) |
| 390 | value_len = 0; |
| 391 | if (name == NULL) |
| 392 | return -EINVAL; |
| 393 | name_len = strlen(name); |
| 394 | if (name_len > 255 || value_len > sb->s_blocksize) |
| 395 | return -ERANGE; |
| 396 | down_write(&EXT2_I(inode)->xattr_sem); |
| 397 | if (EXT2_I(inode)->i_file_acl) { |
| 398 | /* The inode already has an extended attribute block. */ |
| 399 | bh = sb_bread(sb, EXT2_I(inode)->i_file_acl); |
| 400 | error = -EIO; |
| 401 | if (!bh) |
| 402 | goto cleanup; |
| 403 | ea_bdebug(bh, "b_count=%d, refcount=%d", |
| 404 | atomic_read(&(bh->b_count)), |
| 405 | le32_to_cpu(HDR(bh)->h_refcount)); |
| 406 | header = HDR(bh); |
| 407 | end = bh->b_data + bh->b_size; |
| 408 | if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| 409 | header->h_blocks != cpu_to_le32(1)) { |
| 410 | bad_block: ext2_error(sb, "ext2_xattr_set", |
| 411 | "inode %ld: bad block %d", inode->i_ino, |
| 412 | EXT2_I(inode)->i_file_acl); |
| 413 | error = -EIO; |
| 414 | goto cleanup; |
| 415 | } |
| 416 | /* Find the named attribute. */ |
| 417 | here = FIRST_ENTRY(bh); |
| 418 | while (!IS_LAST_ENTRY(here)) { |
| 419 | struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here); |
| 420 | if ((char *)next >= end) |
| 421 | goto bad_block; |
| 422 | if (!here->e_value_block && here->e_value_size) { |
| 423 | size_t offs = le16_to_cpu(here->e_value_offs); |
| 424 | if (offs < min_offs) |
| 425 | min_offs = offs; |
| 426 | } |
| 427 | not_found = name_index - here->e_name_index; |
| 428 | if (!not_found) |
| 429 | not_found = name_len - here->e_name_len; |
| 430 | if (!not_found) |
| 431 | not_found = memcmp(name, here->e_name,name_len); |
| 432 | if (not_found <= 0) |
| 433 | break; |
| 434 | here = next; |
| 435 | } |
| 436 | last = here; |
| 437 | /* We still need to compute min_offs and last. */ |
| 438 | while (!IS_LAST_ENTRY(last)) { |
| 439 | struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last); |
| 440 | if ((char *)next >= end) |
| 441 | goto bad_block; |
| 442 | if (!last->e_value_block && last->e_value_size) { |
| 443 | size_t offs = le16_to_cpu(last->e_value_offs); |
| 444 | if (offs < min_offs) |
| 445 | min_offs = offs; |
| 446 | } |
| 447 | last = next; |
| 448 | } |
| 449 | |
| 450 | /* Check whether we have enough space left. */ |
| 451 | free = min_offs - ((char*)last - (char*)header) - sizeof(__u32); |
| 452 | } else { |
| 453 | /* We will use a new extended attribute block. */ |
| 454 | free = sb->s_blocksize - |
| 455 | sizeof(struct ext2_xattr_header) - sizeof(__u32); |
| 456 | here = last = NULL; /* avoid gcc uninitialized warning. */ |
| 457 | } |
| 458 | |
| 459 | if (not_found) { |
| 460 | /* Request to remove a nonexistent attribute? */ |
| 461 | error = -ENODATA; |
| 462 | if (flags & XATTR_REPLACE) |
| 463 | goto cleanup; |
| 464 | error = 0; |
| 465 | if (value == NULL) |
| 466 | goto cleanup; |
| 467 | } else { |
| 468 | /* Request to create an existing attribute? */ |
| 469 | error = -EEXIST; |
| 470 | if (flags & XATTR_CREATE) |
| 471 | goto cleanup; |
| 472 | if (!here->e_value_block && here->e_value_size) { |
| 473 | size_t size = le32_to_cpu(here->e_value_size); |
| 474 | |
| 475 | if (le16_to_cpu(here->e_value_offs) + size > |
| 476 | sb->s_blocksize || size > sb->s_blocksize) |
| 477 | goto bad_block; |
| 478 | free += EXT2_XATTR_SIZE(size); |
| 479 | } |
| 480 | free += EXT2_XATTR_LEN(name_len); |
| 481 | } |
| 482 | error = -ENOSPC; |
| 483 | if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len)) |
| 484 | goto cleanup; |
| 485 | |
| 486 | /* Here we know that we can set the new attribute. */ |
| 487 | |
| 488 | if (header) { |
| 489 | struct mb_cache_entry *ce; |
| 490 | |
| 491 | /* assert(header == HDR(bh)); */ |
| 492 | ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, |
| 493 | bh->b_blocknr); |
| 494 | lock_buffer(bh); |
| 495 | if (header->h_refcount == cpu_to_le32(1)) { |
| 496 | ea_bdebug(bh, "modifying in-place"); |
| 497 | if (ce) |
| 498 | mb_cache_entry_free(ce); |
| 499 | /* keep the buffer locked while modifying it. */ |
| 500 | } else { |
| 501 | int offset; |
| 502 | |
| 503 | if (ce) |
| 504 | mb_cache_entry_release(ce); |
| 505 | unlock_buffer(bh); |
| 506 | ea_bdebug(bh, "cloning"); |
| 507 | header = kmalloc(bh->b_size, GFP_KERNEL); |
| 508 | error = -ENOMEM; |
| 509 | if (header == NULL) |
| 510 | goto cleanup; |
| 511 | memcpy(header, HDR(bh), bh->b_size); |
| 512 | header->h_refcount = cpu_to_le32(1); |
| 513 | |
| 514 | offset = (char *)here - bh->b_data; |
| 515 | here = ENTRY((char *)header + offset); |
| 516 | offset = (char *)last - bh->b_data; |
| 517 | last = ENTRY((char *)header + offset); |
| 518 | } |
| 519 | } else { |
| 520 | /* Allocate a buffer where we construct the new block. */ |
Panagiotis Issaris | f8314dc | 2006-09-27 01:49:37 -0700 | [diff] [blame] | 521 | header = kzalloc(sb->s_blocksize, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | error = -ENOMEM; |
| 523 | if (header == NULL) |
| 524 | goto cleanup; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | end = (char *)header + sb->s_blocksize; |
| 526 | header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC); |
| 527 | header->h_blocks = header->h_refcount = cpu_to_le32(1); |
| 528 | last = here = ENTRY(header+1); |
| 529 | } |
| 530 | |
| 531 | /* Iff we are modifying the block in-place, bh is locked here. */ |
| 532 | |
| 533 | if (not_found) { |
| 534 | /* Insert the new name. */ |
| 535 | size_t size = EXT2_XATTR_LEN(name_len); |
| 536 | size_t rest = (char *)last - (char *)here; |
| 537 | memmove((char *)here + size, here, rest); |
| 538 | memset(here, 0, size); |
| 539 | here->e_name_index = name_index; |
| 540 | here->e_name_len = name_len; |
| 541 | memcpy(here->e_name, name, name_len); |
| 542 | } else { |
| 543 | if (!here->e_value_block && here->e_value_size) { |
| 544 | char *first_val = (char *)header + min_offs; |
| 545 | size_t offs = le16_to_cpu(here->e_value_offs); |
| 546 | char *val = (char *)header + offs; |
| 547 | size_t size = EXT2_XATTR_SIZE( |
| 548 | le32_to_cpu(here->e_value_size)); |
| 549 | |
| 550 | if (size == EXT2_XATTR_SIZE(value_len)) { |
| 551 | /* The old and the new value have the same |
| 552 | size. Just replace. */ |
| 553 | here->e_value_size = cpu_to_le32(value_len); |
| 554 | memset(val + size - EXT2_XATTR_PAD, 0, |
| 555 | EXT2_XATTR_PAD); /* Clear pad bytes. */ |
| 556 | memcpy(val, value, value_len); |
| 557 | goto skip_replace; |
| 558 | } |
| 559 | |
| 560 | /* Remove the old value. */ |
| 561 | memmove(first_val + size, first_val, val - first_val); |
| 562 | memset(first_val, 0, size); |
| 563 | here->e_value_offs = 0; |
| 564 | min_offs += size; |
| 565 | |
| 566 | /* Adjust all value offsets. */ |
| 567 | last = ENTRY(header+1); |
| 568 | while (!IS_LAST_ENTRY(last)) { |
| 569 | size_t o = le16_to_cpu(last->e_value_offs); |
| 570 | if (!last->e_value_block && o < offs) |
| 571 | last->e_value_offs = |
| 572 | cpu_to_le16(o + size); |
| 573 | last = EXT2_XATTR_NEXT(last); |
| 574 | } |
| 575 | } |
| 576 | if (value == NULL) { |
| 577 | /* Remove the old name. */ |
| 578 | size_t size = EXT2_XATTR_LEN(name_len); |
| 579 | last = ENTRY((char *)last - size); |
| 580 | memmove(here, (char*)here + size, |
| 581 | (char*)last - (char*)here); |
| 582 | memset(last, 0, size); |
| 583 | } |
| 584 | } |
| 585 | |
| 586 | if (value != NULL) { |
| 587 | /* Insert the new value. */ |
| 588 | here->e_value_size = cpu_to_le32(value_len); |
| 589 | if (value_len) { |
| 590 | size_t size = EXT2_XATTR_SIZE(value_len); |
| 591 | char *val = (char *)header + min_offs - size; |
| 592 | here->e_value_offs = |
| 593 | cpu_to_le16((char *)val - (char *)header); |
| 594 | memset(val + size - EXT2_XATTR_PAD, 0, |
| 595 | EXT2_XATTR_PAD); /* Clear the pad bytes. */ |
| 596 | memcpy(val, value, value_len); |
| 597 | } |
| 598 | } |
| 599 | |
| 600 | skip_replace: |
| 601 | if (IS_LAST_ENTRY(ENTRY(header+1))) { |
| 602 | /* This block is now empty. */ |
| 603 | if (bh && header == HDR(bh)) |
| 604 | unlock_buffer(bh); /* we were modifying in-place. */ |
| 605 | error = ext2_xattr_set2(inode, bh, NULL); |
| 606 | } else { |
| 607 | ext2_xattr_rehash(header, here); |
| 608 | if (bh && header == HDR(bh)) |
| 609 | unlock_buffer(bh); /* we were modifying in-place. */ |
| 610 | error = ext2_xattr_set2(inode, bh, header); |
| 611 | } |
| 612 | |
| 613 | cleanup: |
| 614 | brelse(bh); |
| 615 | if (!(bh && header == HDR(bh))) |
| 616 | kfree(header); |
| 617 | up_write(&EXT2_I(inode)->xattr_sem); |
| 618 | |
| 619 | return error; |
| 620 | } |
| 621 | |
| 622 | /* |
| 623 | * Second half of ext2_xattr_set(): Update the file system. |
| 624 | */ |
| 625 | static int |
| 626 | ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, |
| 627 | struct ext2_xattr_header *header) |
| 628 | { |
| 629 | struct super_block *sb = inode->i_sb; |
| 630 | struct buffer_head *new_bh = NULL; |
| 631 | int error; |
| 632 | |
| 633 | if (header) { |
| 634 | new_bh = ext2_xattr_cache_find(inode, header); |
| 635 | if (new_bh) { |
| 636 | /* We found an identical block in the cache. */ |
| 637 | if (new_bh == old_bh) { |
| 638 | ea_bdebug(new_bh, "keeping this block"); |
| 639 | } else { |
| 640 | /* The old block is released after updating |
| 641 | the inode. */ |
| 642 | ea_bdebug(new_bh, "reusing block"); |
| 643 | |
| 644 | error = -EDQUOT; |
| 645 | if (DQUOT_ALLOC_BLOCK(inode, 1)) { |
| 646 | unlock_buffer(new_bh); |
| 647 | goto cleanup; |
| 648 | } |
| 649 | HDR(new_bh)->h_refcount = cpu_to_le32(1 + |
| 650 | le32_to_cpu(HDR(new_bh)->h_refcount)); |
| 651 | ea_bdebug(new_bh, "refcount now=%d", |
| 652 | le32_to_cpu(HDR(new_bh)->h_refcount)); |
| 653 | } |
| 654 | unlock_buffer(new_bh); |
| 655 | } else if (old_bh && header == HDR(old_bh)) { |
| 656 | /* Keep this block. No need to lock the block as we |
| 657 | don't need to change the reference count. */ |
| 658 | new_bh = old_bh; |
| 659 | get_bh(new_bh); |
| 660 | ext2_xattr_cache_insert(new_bh); |
| 661 | } else { |
| 662 | /* We need to allocate a new block */ |
| 663 | int goal = le32_to_cpu(EXT2_SB(sb)->s_es-> |
| 664 | s_first_data_block) + |
| 665 | EXT2_I(inode)->i_block_group * |
| 666 | EXT2_BLOCKS_PER_GROUP(sb); |
| 667 | int block = ext2_new_block(inode, goal, |
| 668 | NULL, NULL, &error); |
| 669 | if (error) |
| 670 | goto cleanup; |
| 671 | ea_idebug(inode, "creating block %d", block); |
| 672 | |
| 673 | new_bh = sb_getblk(sb, block); |
| 674 | if (!new_bh) { |
| 675 | ext2_free_blocks(inode, block, 1); |
| 676 | error = -EIO; |
| 677 | goto cleanup; |
| 678 | } |
| 679 | lock_buffer(new_bh); |
| 680 | memcpy(new_bh->b_data, header, new_bh->b_size); |
| 681 | set_buffer_uptodate(new_bh); |
| 682 | unlock_buffer(new_bh); |
| 683 | ext2_xattr_cache_insert(new_bh); |
| 684 | |
| 685 | ext2_xattr_update_super_block(sb); |
| 686 | } |
| 687 | mark_buffer_dirty(new_bh); |
| 688 | if (IS_SYNC(inode)) { |
| 689 | sync_dirty_buffer(new_bh); |
| 690 | error = -EIO; |
| 691 | if (buffer_req(new_bh) && !buffer_uptodate(new_bh)) |
| 692 | goto cleanup; |
| 693 | } |
| 694 | } |
| 695 | |
| 696 | /* Update the inode. */ |
| 697 | EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; |
| 698 | inode->i_ctime = CURRENT_TIME_SEC; |
| 699 | if (IS_SYNC(inode)) { |
| 700 | error = ext2_sync_inode (inode); |
| 701 | /* In case sync failed due to ENOSPC the inode was actually |
| 702 | * written (only some dirty data were not) so we just proceed |
| 703 | * as if nothing happened and cleanup the unused block */ |
| 704 | if (error && error != -ENOSPC) { |
| 705 | if (new_bh && new_bh != old_bh) |
| 706 | DQUOT_FREE_BLOCK(inode, 1); |
| 707 | goto cleanup; |
| 708 | } |
| 709 | } else |
| 710 | mark_inode_dirty(inode); |
| 711 | |
| 712 | error = 0; |
| 713 | if (old_bh && old_bh != new_bh) { |
| 714 | struct mb_cache_entry *ce; |
| 715 | |
| 716 | /* |
| 717 | * If there was an old block and we are no longer using it, |
| 718 | * release the old block. |
| 719 | */ |
| 720 | ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev, |
| 721 | old_bh->b_blocknr); |
| 722 | lock_buffer(old_bh); |
| 723 | if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) { |
| 724 | /* Free the old block. */ |
| 725 | if (ce) |
| 726 | mb_cache_entry_free(ce); |
| 727 | ea_bdebug(old_bh, "freeing"); |
| 728 | ext2_free_blocks(inode, old_bh->b_blocknr, 1); |
| 729 | /* We let our caller release old_bh, so we |
| 730 | * need to duplicate the buffer before. */ |
| 731 | get_bh(old_bh); |
| 732 | bforget(old_bh); |
| 733 | } else { |
| 734 | /* Decrement the refcount only. */ |
| 735 | HDR(old_bh)->h_refcount = cpu_to_le32( |
| 736 | le32_to_cpu(HDR(old_bh)->h_refcount) - 1); |
| 737 | if (ce) |
| 738 | mb_cache_entry_release(ce); |
| 739 | DQUOT_FREE_BLOCK(inode, 1); |
| 740 | mark_buffer_dirty(old_bh); |
| 741 | ea_bdebug(old_bh, "refcount now=%d", |
| 742 | le32_to_cpu(HDR(old_bh)->h_refcount)); |
| 743 | } |
| 744 | unlock_buffer(old_bh); |
| 745 | } |
| 746 | |
| 747 | cleanup: |
| 748 | brelse(new_bh); |
| 749 | |
| 750 | return error; |
| 751 | } |
| 752 | |
| 753 | /* |
| 754 | * ext2_xattr_delete_inode() |
| 755 | * |
| 756 | * Free extended attribute resources associated with this inode. This |
| 757 | * is called immediately before an inode is freed. |
| 758 | */ |
| 759 | void |
| 760 | ext2_xattr_delete_inode(struct inode *inode) |
| 761 | { |
| 762 | struct buffer_head *bh = NULL; |
| 763 | struct mb_cache_entry *ce; |
| 764 | |
| 765 | down_write(&EXT2_I(inode)->xattr_sem); |
| 766 | if (!EXT2_I(inode)->i_file_acl) |
| 767 | goto cleanup; |
| 768 | bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); |
| 769 | if (!bh) { |
| 770 | ext2_error(inode->i_sb, "ext2_xattr_delete_inode", |
| 771 | "inode %ld: block %d read error", inode->i_ino, |
| 772 | EXT2_I(inode)->i_file_acl); |
| 773 | goto cleanup; |
| 774 | } |
| 775 | ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); |
| 776 | if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| 777 | HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| 778 | ext2_error(inode->i_sb, "ext2_xattr_delete_inode", |
| 779 | "inode %ld: bad block %d", inode->i_ino, |
| 780 | EXT2_I(inode)->i_file_acl); |
| 781 | goto cleanup; |
| 782 | } |
| 783 | ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr); |
| 784 | lock_buffer(bh); |
| 785 | if (HDR(bh)->h_refcount == cpu_to_le32(1)) { |
| 786 | if (ce) |
| 787 | mb_cache_entry_free(ce); |
| 788 | ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1); |
| 789 | get_bh(bh); |
| 790 | bforget(bh); |
Peter Staubach | b2f4903 | 2006-02-17 13:52:36 -0800 | [diff] [blame] | 791 | unlock_buffer(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 792 | } else { |
| 793 | HDR(bh)->h_refcount = cpu_to_le32( |
| 794 | le32_to_cpu(HDR(bh)->h_refcount) - 1); |
| 795 | if (ce) |
| 796 | mb_cache_entry_release(ce); |
Peter Staubach | b2f4903 | 2006-02-17 13:52:36 -0800 | [diff] [blame] | 797 | ea_bdebug(bh, "refcount now=%d", |
| 798 | le32_to_cpu(HDR(bh)->h_refcount)); |
| 799 | unlock_buffer(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 800 | mark_buffer_dirty(bh); |
| 801 | if (IS_SYNC(inode)) |
| 802 | sync_dirty_buffer(bh); |
| 803 | DQUOT_FREE_BLOCK(inode, 1); |
| 804 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 805 | EXT2_I(inode)->i_file_acl = 0; |
| 806 | |
| 807 | cleanup: |
| 808 | brelse(bh); |
| 809 | up_write(&EXT2_I(inode)->xattr_sem); |
| 810 | } |
| 811 | |
| 812 | /* |
| 813 | * ext2_xattr_put_super() |
| 814 | * |
| 815 | * This is called when a file system is unmounted. |
| 816 | */ |
| 817 | void |
| 818 | ext2_xattr_put_super(struct super_block *sb) |
| 819 | { |
Andreas Gruenbacher | 8c52ab4 | 2005-07-27 11:45:15 -0700 | [diff] [blame] | 820 | mb_cache_shrink(sb->s_bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 821 | } |
| 822 | |
| 823 | |
| 824 | /* |
| 825 | * ext2_xattr_cache_insert() |
| 826 | * |
| 827 | * Create a new entry in the extended attribute cache, and insert |
| 828 | * it unless such an entry is already in the cache. |
| 829 | * |
| 830 | * Returns 0, or a negative error number on failure. |
| 831 | */ |
| 832 | static int |
| 833 | ext2_xattr_cache_insert(struct buffer_head *bh) |
| 834 | { |
| 835 | __u32 hash = le32_to_cpu(HDR(bh)->h_hash); |
| 836 | struct mb_cache_entry *ce; |
| 837 | int error; |
| 838 | |
| 839 | ce = mb_cache_entry_alloc(ext2_xattr_cache); |
| 840 | if (!ce) |
| 841 | return -ENOMEM; |
| 842 | error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); |
| 843 | if (error) { |
| 844 | mb_cache_entry_free(ce); |
| 845 | if (error == -EBUSY) { |
| 846 | ea_bdebug(bh, "already in cache (%d cache entries)", |
| 847 | atomic_read(&ext2_xattr_cache->c_entry_count)); |
| 848 | error = 0; |
| 849 | } |
| 850 | } else { |
| 851 | ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash, |
| 852 | atomic_read(&ext2_xattr_cache->c_entry_count)); |
| 853 | mb_cache_entry_release(ce); |
| 854 | } |
| 855 | return error; |
| 856 | } |
| 857 | |
| 858 | /* |
| 859 | * ext2_xattr_cmp() |
| 860 | * |
| 861 | * Compare two extended attribute blocks for equality. |
| 862 | * |
| 863 | * Returns 0 if the blocks are equal, 1 if they differ, and |
| 864 | * a negative error number on errors. |
| 865 | */ |
| 866 | static int |
| 867 | ext2_xattr_cmp(struct ext2_xattr_header *header1, |
| 868 | struct ext2_xattr_header *header2) |
| 869 | { |
| 870 | struct ext2_xattr_entry *entry1, *entry2; |
| 871 | |
| 872 | entry1 = ENTRY(header1+1); |
| 873 | entry2 = ENTRY(header2+1); |
| 874 | while (!IS_LAST_ENTRY(entry1)) { |
| 875 | if (IS_LAST_ENTRY(entry2)) |
| 876 | return 1; |
| 877 | if (entry1->e_hash != entry2->e_hash || |
| 878 | entry1->e_name_index != entry2->e_name_index || |
| 879 | entry1->e_name_len != entry2->e_name_len || |
| 880 | entry1->e_value_size != entry2->e_value_size || |
| 881 | memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) |
| 882 | return 1; |
| 883 | if (entry1->e_value_block != 0 || entry2->e_value_block != 0) |
| 884 | return -EIO; |
| 885 | if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), |
| 886 | (char *)header2 + le16_to_cpu(entry2->e_value_offs), |
| 887 | le32_to_cpu(entry1->e_value_size))) |
| 888 | return 1; |
| 889 | |
| 890 | entry1 = EXT2_XATTR_NEXT(entry1); |
| 891 | entry2 = EXT2_XATTR_NEXT(entry2); |
| 892 | } |
| 893 | if (!IS_LAST_ENTRY(entry2)) |
| 894 | return 1; |
| 895 | return 0; |
| 896 | } |
| 897 | |
| 898 | /* |
| 899 | * ext2_xattr_cache_find() |
| 900 | * |
| 901 | * Find an identical extended attribute block. |
| 902 | * |
| 903 | * Returns a locked buffer head to the block found, or NULL if such |
| 904 | * a block was not found or an error occurred. |
| 905 | */ |
| 906 | static struct buffer_head * |
| 907 | ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) |
| 908 | { |
| 909 | __u32 hash = le32_to_cpu(header->h_hash); |
| 910 | struct mb_cache_entry *ce; |
| 911 | |
| 912 | if (!header->h_hash) |
| 913 | return NULL; /* never share */ |
| 914 | ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); |
| 915 | again: |
| 916 | ce = mb_cache_entry_find_first(ext2_xattr_cache, 0, |
| 917 | inode->i_sb->s_bdev, hash); |
| 918 | while (ce) { |
| 919 | struct buffer_head *bh; |
| 920 | |
| 921 | if (IS_ERR(ce)) { |
| 922 | if (PTR_ERR(ce) == -EAGAIN) |
| 923 | goto again; |
| 924 | break; |
| 925 | } |
| 926 | |
| 927 | bh = sb_bread(inode->i_sb, ce->e_block); |
| 928 | if (!bh) { |
| 929 | ext2_error(inode->i_sb, "ext2_xattr_cache_find", |
| 930 | "inode %ld: block %ld read error", |
| 931 | inode->i_ino, (unsigned long) ce->e_block); |
| 932 | } else { |
| 933 | lock_buffer(bh); |
| 934 | if (le32_to_cpu(HDR(bh)->h_refcount) > |
| 935 | EXT2_XATTR_REFCOUNT_MAX) { |
| 936 | ea_idebug(inode, "block %ld refcount %d>%d", |
| 937 | (unsigned long) ce->e_block, |
| 938 | le32_to_cpu(HDR(bh)->h_refcount), |
| 939 | EXT2_XATTR_REFCOUNT_MAX); |
| 940 | } else if (!ext2_xattr_cmp(header, HDR(bh))) { |
| 941 | ea_bdebug(bh, "b_count=%d", |
| 942 | atomic_read(&(bh->b_count))); |
| 943 | mb_cache_entry_release(ce); |
| 944 | return bh; |
| 945 | } |
| 946 | unlock_buffer(bh); |
| 947 | brelse(bh); |
| 948 | } |
| 949 | ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); |
| 950 | } |
| 951 | return NULL; |
| 952 | } |
| 953 | |
| 954 | #define NAME_HASH_SHIFT 5 |
| 955 | #define VALUE_HASH_SHIFT 16 |
| 956 | |
| 957 | /* |
| 958 | * ext2_xattr_hash_entry() |
| 959 | * |
| 960 | * Compute the hash of an extended attribute. |
| 961 | */ |
| 962 | static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header, |
| 963 | struct ext2_xattr_entry *entry) |
| 964 | { |
| 965 | __u32 hash = 0; |
| 966 | char *name = entry->e_name; |
| 967 | int n; |
| 968 | |
| 969 | for (n=0; n < entry->e_name_len; n++) { |
| 970 | hash = (hash << NAME_HASH_SHIFT) ^ |
| 971 | (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ |
| 972 | *name++; |
| 973 | } |
| 974 | |
| 975 | if (entry->e_value_block == 0 && entry->e_value_size != 0) { |
| 976 | __le32 *value = (__le32 *)((char *)header + |
| 977 | le16_to_cpu(entry->e_value_offs)); |
| 978 | for (n = (le32_to_cpu(entry->e_value_size) + |
| 979 | EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) { |
| 980 | hash = (hash << VALUE_HASH_SHIFT) ^ |
| 981 | (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ |
| 982 | le32_to_cpu(*value++); |
| 983 | } |
| 984 | } |
| 985 | entry->e_hash = cpu_to_le32(hash); |
| 986 | } |
| 987 | |
| 988 | #undef NAME_HASH_SHIFT |
| 989 | #undef VALUE_HASH_SHIFT |
| 990 | |
| 991 | #define BLOCK_HASH_SHIFT 16 |
| 992 | |
| 993 | /* |
| 994 | * ext2_xattr_rehash() |
| 995 | * |
| 996 | * Re-compute the extended attribute hash value after an entry has changed. |
| 997 | */ |
| 998 | static void ext2_xattr_rehash(struct ext2_xattr_header *header, |
| 999 | struct ext2_xattr_entry *entry) |
| 1000 | { |
| 1001 | struct ext2_xattr_entry *here; |
| 1002 | __u32 hash = 0; |
| 1003 | |
| 1004 | ext2_xattr_hash_entry(header, entry); |
| 1005 | here = ENTRY(header+1); |
| 1006 | while (!IS_LAST_ENTRY(here)) { |
| 1007 | if (!here->e_hash) { |
| 1008 | /* Block is not shared if an entry's hash value == 0 */ |
| 1009 | hash = 0; |
| 1010 | break; |
| 1011 | } |
| 1012 | hash = (hash << BLOCK_HASH_SHIFT) ^ |
| 1013 | (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ |
| 1014 | le32_to_cpu(here->e_hash); |
| 1015 | here = EXT2_XATTR_NEXT(here); |
| 1016 | } |
| 1017 | header->h_hash = cpu_to_le32(hash); |
| 1018 | } |
| 1019 | |
| 1020 | #undef BLOCK_HASH_SHIFT |
| 1021 | |
| 1022 | int __init |
| 1023 | init_ext2_xattr(void) |
| 1024 | { |
| 1025 | ext2_xattr_cache = mb_cache_create("ext2_xattr", NULL, |
| 1026 | sizeof(struct mb_cache_entry) + |
| 1027 | sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); |
| 1028 | if (!ext2_xattr_cache) |
| 1029 | return -ENOMEM; |
| 1030 | return 0; |
| 1031 | } |
| 1032 | |
| 1033 | void |
| 1034 | exit_ext2_xattr(void) |
| 1035 | { |
| 1036 | mb_cache_destroy(ext2_xattr_cache); |
| 1037 | } |