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/* |
| 2 |
* linux/fs/ext3/xattr.c |
| 3 |
* |
| 4 |
* Copyright (C) 2001-2003 by Andreas Gruenbacher, <agruen@suse.de> |
| 5 |
* |
| 6 |
* Fix by Harrison Xing <harrison@mountainviewdata.com>. |
| 7 |
* Ext3 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 |
*/ |
| 11 |
|
| 12 |
/* |
| 13 |
* Extended attributes are stored on disk blocks allocated outside of |
| 14 |
* any inode. The i_file_acl field is then made to point to this allocated |
| 15 |
* block. If all extended attributes of an inode are identical, these |
| 16 |
* inodes may share the same extended attribute block. Such situations |
| 17 |
* are automatically detected by keeping a cache of recent attribute block |
| 18 |
* numbers and hashes over the block's contents in memory. |
| 19 |
* |
| 20 |
* |
| 21 |
* Extended attribute block layout: |
| 22 |
* |
| 23 |
* +------------------+ |
| 24 |
* | header | |
| 25 |
* | entry 1 | | |
| 26 |
* | entry 2 | | growing downwards |
| 27 |
* | entry 3 | v |
| 28 |
* | four null bytes | |
| 29 |
* | . . . | |
| 30 |
* | value 1 | ^ |
| 31 |
* | value 3 | | growing upwards |
| 32 |
* | value 2 | | |
| 33 |
* +------------------+ |
| 34 |
* |
| 35 |
* The block header is followed by multiple entry descriptors. These entry |
| 36 |
* descriptors are variable in size, and alligned to EXT3_XATTR_PAD |
| 37 |
* byte boundaries. The entry descriptors are sorted by attribute name, |
| 38 |
* so that two extended attribute blocks can be compared efficiently. |
| 39 |
* |
| 40 |
* Attribute values are aligned to the end of the block, stored in |
| 41 |
* no specific order. They are also padded to EXT3_XATTR_PAD byte |
| 42 |
* boundaries. No additional gaps are left between them. |
| 43 |
* |
| 44 |
* Locking strategy |
| 45 |
* ---------------- |
| 46 |
* EXT3_I(inode)->i_file_acl is protected by EXT3_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 will change. Multiple writers to an EA block are synchronized |
| 50 |
* by the bh lock. No more than a single bh lock is held at any time, |
| 51 |
* which avoids deadlocks. |
| 52 |
*/ |
| 53 |
|
| 54 |
#include <linux/fs.h> |
| 55 |
#include <linux/locks.h> |
| 56 |
#include <linux/slab.h> |
| 57 |
#include <linux/ext3_jbd.h> |
| 58 |
#include <linux/ext3_fs.h> |
| 59 |
#include <linux/ext3_xattr.h> |
| 60 |
#include <linux/mbcache.h> |
| 61 |
#include <linux/quotaops.h> |
| 62 |
#include <linux/rwsem.h> |
| 63 |
|
| 64 |
#define HDR(bh) ((struct ext3_xattr_header *)((bh)->b_data)) |
| 65 |
#define ENTRY(ptr) ((struct ext3_xattr_entry *)(ptr)) |
| 66 |
#define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1) |
| 67 |
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) |
| 68 |
|
| 69 |
#ifdef EXT3_XATTR_DEBUG |
| 70 |
# define ea_idebug(inode, f...) do { \ |
| 71 |
printk(KERN_DEBUG "inode %s:%ld: ", \ |
| 72 |
kdevname(inode->i_dev), inode->i_ino); \ |
| 73 |
printk(f); \ |
| 74 |
printk("\n"); \ |
| 75 |
} while (0) |
| 76 |
# define ea_bdebug(bh, f...) do { \ |
| 77 |
printk(KERN_DEBUG "block %s:%ld: ", \ |
| 78 |
kdevname(bh->b_dev), bh->b_blocknr); \ |
| 79 |
printk(f); \ |
| 80 |
printk("\n"); \ |
| 81 |
} while (0) |
| 82 |
#else |
| 83 |
# define ea_idebug(f...) |
| 84 |
# define ea_bdebug(f...) |
| 85 |
#endif |
| 86 |
|
| 87 |
static int ext3_xattr_set_handle2(handle_t *, struct inode *, |
| 88 |
struct buffer_head *, |
| 89 |
struct ext3_xattr_header *); |
| 90 |
|
| 91 |
#ifdef CONFIG_EXT3_FS_XATTR_SHARING |
| 92 |
|
| 93 |
static int ext3_xattr_cache_insert(struct buffer_head *); |
| 94 |
static struct buffer_head *ext3_xattr_cache_find(handle_t *, struct inode *, |
| 95 |
struct ext3_xattr_header *); |
| 96 |
static void ext3_xattr_cache_remove(struct buffer_head *); |
| 97 |
static void ext3_xattr_rehash(struct ext3_xattr_header *, |
| 98 |
struct ext3_xattr_entry *); |
| 99 |
|
| 100 |
static struct mb_cache *ext3_xattr_cache; |
| 101 |
|
| 102 |
#else |
| 103 |
# define ext3_xattr_cache_insert(bh) 0 |
| 104 |
# define ext3_xattr_cache_find(handle, inode, header) NULL |
| 105 |
# define ext3_xattr_cache_remove(bh) while(0) {} |
| 106 |
# define ext3_xattr_rehash(header, entry) while(0) {} |
| 107 |
#endif |
| 108 |
|
| 109 |
struct ext3_xattr_handler *ext3_xattr_handlers[EXT3_XATTR_INDEX_MAX]; |
| 110 |
rwlock_t ext3_handler_lock = RW_LOCK_UNLOCKED; |
| 111 |
|
| 112 |
int |
| 113 |
ext3_xattr_register(int name_index, struct ext3_xattr_handler *handler) |
| 114 |
{ |
| 115 |
int error = -EINVAL; |
| 116 |
|
| 117 |
if (name_index > 0 && name_index <= EXT3_XATTR_INDEX_MAX) { |
| 118 |
write_lock(&ext3_handler_lock); |
| 119 |
if (!ext3_xattr_handlers[name_index-1]) { |
| 120 |
ext3_xattr_handlers[name_index-1] = handler; |
| 121 |
error = 0; |
| 122 |
} |
| 123 |
write_unlock(&ext3_handler_lock); |
| 124 |
} |
| 125 |
return error; |
| 126 |
} |
| 127 |
|
| 128 |
void |
| 129 |
ext3_xattr_unregister(int name_index, struct ext3_xattr_handler *handler) |
| 130 |
{ |
| 131 |
if (name_index > 0 || name_index <= EXT3_XATTR_INDEX_MAX) { |
| 132 |
write_lock(&ext3_handler_lock); |
| 133 |
ext3_xattr_handlers[name_index-1] = NULL; |
| 134 |
write_unlock(&ext3_handler_lock); |
| 135 |
} |
| 136 |
} |
| 137 |
|
| 138 |
static inline const char * |
| 139 |
strcmp_prefix(const char *a, const char *a_prefix) |
| 140 |
{ |
| 141 |
while (*a_prefix && *a == *a_prefix) { |
| 142 |
a++; |
| 143 |
a_prefix++; |
| 144 |
} |
| 145 |
return *a_prefix ? NULL : a; |
| 146 |
} |
| 147 |
|
| 148 |
/* |
| 149 |
* Decode the extended attribute name, and translate it into |
| 150 |
* the name_index and name suffix. |
| 151 |
*/ |
| 152 |
static inline struct ext3_xattr_handler * |
| 153 |
ext3_xattr_resolve_name(const char **name) |
| 154 |
{ |
| 155 |
struct ext3_xattr_handler *handler = NULL; |
| 156 |
int i; |
| 157 |
|
| 158 |
if (!*name) |
| 159 |
return NULL; |
| 160 |
read_lock(&ext3_handler_lock); |
| 161 |
for (i=0; i<EXT3_XATTR_INDEX_MAX; i++) { |
| 162 |
if (ext3_xattr_handlers[i]) { |
| 163 |
const char *n = strcmp_prefix(*name, |
| 164 |
ext3_xattr_handlers[i]->prefix); |
| 165 |
if (n) { |
| 166 |
handler = ext3_xattr_handlers[i]; |
| 167 |
*name = n; |
| 168 |
break; |
| 169 |
} |
| 170 |
} |
| 171 |
} |
| 172 |
read_unlock(&ext3_handler_lock); |
| 173 |
return handler; |
| 174 |
} |
| 175 |
|
| 176 |
static inline struct ext3_xattr_handler * |
| 177 |
ext3_xattr_handler(int name_index) |
| 178 |
{ |
| 179 |
struct ext3_xattr_handler *handler = NULL; |
| 180 |
if (name_index > 0 && name_index <= EXT3_XATTR_INDEX_MAX) { |
| 181 |
read_lock(&ext3_handler_lock); |
| 182 |
handler = ext3_xattr_handlers[name_index-1]; |
| 183 |
read_unlock(&ext3_handler_lock); |
| 184 |
} |
| 185 |
return handler; |
| 186 |
} |
| 187 |
|
| 188 |
/* |
| 189 |
* Inode operation getxattr() |
| 190 |
* |
| 191 |
* dentry->d_inode->i_sem: don't care |
| 192 |
* BKL: held |
| 193 |
*/ |
| 194 |
ssize_t |
| 195 |
ext3_getxattr(struct dentry *dentry, const char *name, |
| 196 |
void *buffer, size_t size) |
| 197 |
{ |
| 198 |
struct ext3_xattr_handler *handler; |
| 199 |
struct inode *inode = dentry->d_inode; |
| 200 |
|
| 201 |
handler = ext3_xattr_resolve_name(&name); |
| 202 |
if (!handler) |
| 203 |
return -EOPNOTSUPP; |
| 204 |
return handler->get(inode, name, buffer, size); |
| 205 |
} |
| 206 |
|
| 207 |
/* |
| 208 |
* Inode operation listxattr() |
| 209 |
* |
| 210 |
* dentry->d_inode->i_sem: don't care |
| 211 |
* BKL: held |
| 212 |
*/ |
| 213 |
ssize_t |
| 214 |
ext3_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| 215 |
{ |
| 216 |
return ext3_xattr_list(dentry->d_inode, buffer, size); |
| 217 |
} |
| 218 |
|
| 219 |
/* |
| 220 |
* Inode operation setxattr() |
| 221 |
* |
| 222 |
* dentry->d_inode->i_sem: down |
| 223 |
* BKL: held |
| 224 |
*/ |
| 225 |
int |
| 226 |
ext3_setxattr(struct dentry *dentry, const char *name, |
| 227 |
const void *value, size_t size, int flags) |
| 228 |
{ |
| 229 |
struct ext3_xattr_handler *handler; |
| 230 |
struct inode *inode = dentry->d_inode; |
| 231 |
|
| 232 |
if (size == 0) |
| 233 |
value = ""; /* empty EA, do not remove */ |
| 234 |
handler = ext3_xattr_resolve_name(&name); |
| 235 |
if (!handler) |
| 236 |
return -EOPNOTSUPP; |
| 237 |
return handler->set(inode, name, value, size, flags); |
| 238 |
} |
| 239 |
|
| 240 |
/* |
| 241 |
* Inode operation removexattr() |
| 242 |
* |
| 243 |
* dentry->d_inode->i_sem: down |
| 244 |
* BKL: held |
| 245 |
*/ |
| 246 |
int |
| 247 |
ext3_removexattr(struct dentry *dentry, const char *name) |
| 248 |
{ |
| 249 |
struct ext3_xattr_handler *handler; |
| 250 |
struct inode *inode = dentry->d_inode; |
| 251 |
|
| 252 |
handler = ext3_xattr_resolve_name(&name); |
| 253 |
if (!handler) |
| 254 |
return -EOPNOTSUPP; |
| 255 |
return handler->set(inode, name, NULL, 0, XATTR_REPLACE); |
| 256 |
} |
| 257 |
|
| 258 |
/* |
| 259 |
* ext3_xattr_get() |
| 260 |
* |
| 261 |
* Copy an extended attribute into the buffer |
| 262 |
* provided, or compute the buffer size required. |
| 263 |
* Buffer is NULL to compute the size of the buffer required. |
| 264 |
* |
| 265 |
* Returns a negative error number on failure, or the number of bytes |
| 266 |
* used / required on success. |
| 267 |
*/ |
| 268 |
int |
| 269 |
ext3_xattr_get(struct inode *inode, int name_index, const char *name, |
| 270 |
void *buffer, size_t buffer_size) |
| 271 |
{ |
| 272 |
struct buffer_head *bh = NULL; |
| 273 |
struct ext3_xattr_entry *entry; |
| 274 |
size_t size, name_len; |
| 275 |
char *end; |
| 276 |
int error; |
| 277 |
|
| 278 |
ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", |
| 279 |
name_index, name, buffer, (long)buffer_size); |
| 280 |
|
| 281 |
if (name == NULL) |
| 282 |
return -EINVAL; |
| 283 |
down_read(&EXT3_I(inode)->xattr_sem); |
| 284 |
error = -ENODATA; |
| 285 |
if (!EXT3_I(inode)->i_file_acl) |
| 286 |
goto cleanup; |
| 287 |
ea_idebug(inode, "reading block %d", EXT3_I(inode)->i_file_acl); |
| 288 |
bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl); |
| 289 |
error = -EIO; |
| 290 |
if (!bh) |
| 291 |
goto cleanup; |
| 292 |
ea_bdebug(bh, "b_count=%d, refcount=%d", |
| 293 |
atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); |
| 294 |
end = bh->b_data + bh->b_size; |
| 295 |
if (HDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) || |
| 296 |
HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| 297 |
bad_block: ext3_error(inode->i_sb, "ext3_xattr_get", |
| 298 |
"inode %ld: bad block %d", inode->i_ino, |
| 299 |
EXT3_I(inode)->i_file_acl); |
| 300 |
error = -EIO; |
| 301 |
goto cleanup; |
| 302 |
} |
| 303 |
/* find named attribute */ |
| 304 |
name_len = strlen(name); |
| 305 |
|
| 306 |
error = -ERANGE; |
| 307 |
if (name_len > 255) |
| 308 |
goto cleanup; |
| 309 |
entry = FIRST_ENTRY(bh); |
| 310 |
while (!IS_LAST_ENTRY(entry)) { |
| 311 |
struct ext3_xattr_entry *next = |
| 312 |
EXT3_XATTR_NEXT(entry); |
| 313 |
if ((char *)next >= end) |
| 314 |
goto bad_block; |
| 315 |
if (name_index == entry->e_name_index && |
| 316 |
name_len == entry->e_name_len && |
| 317 |
memcmp(name, entry->e_name, name_len) == 0) |
| 318 |
goto found; |
| 319 |
entry = next; |
| 320 |
} |
| 321 |
/* Check the remaining name entries */ |
| 322 |
while (!IS_LAST_ENTRY(entry)) { |
| 323 |
struct ext3_xattr_entry *next = |
| 324 |
EXT3_XATTR_NEXT(entry); |
| 325 |
if ((char *)next >= end) |
| 326 |
goto bad_block; |
| 327 |
entry = next; |
| 328 |
} |
| 329 |
if (ext3_xattr_cache_insert(bh)) |
| 330 |
ea_idebug(inode, "cache insert failed"); |
| 331 |
error = -ENODATA; |
| 332 |
goto cleanup; |
| 333 |
found: |
| 334 |
/* check the buffer size */ |
| 335 |
if (entry->e_value_block != 0) |
| 336 |
goto bad_block; |
| 337 |
size = le32_to_cpu(entry->e_value_size); |
| 338 |
if (size > inode->i_sb->s_blocksize || |
| 339 |
le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize) |
| 340 |
goto bad_block; |
| 341 |
|
| 342 |
if (ext3_xattr_cache_insert(bh)) |
| 343 |
ea_idebug(inode, "cache insert failed"); |
| 344 |
if (buffer) { |
| 345 |
error = -ERANGE; |
| 346 |
if (size > buffer_size) |
| 347 |
goto cleanup; |
| 348 |
/* return value of attribute */ |
| 349 |
memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), |
| 350 |
size); |
| 351 |
} |
| 352 |
error = size; |
| 353 |
|
| 354 |
cleanup: |
| 355 |
brelse(bh); |
| 356 |
up_read(&EXT3_I(inode)->xattr_sem); |
| 357 |
|
| 358 |
return error; |
| 359 |
} |
| 360 |
|
| 361 |
/* |
| 362 |
* ext3_xattr_list() |
| 363 |
* |
| 364 |
* Copy a list of attribute names into the buffer |
| 365 |
* provided, or compute the buffer size required. |
| 366 |
* Buffer is NULL to compute the size of the buffer required. |
| 367 |
* |
| 368 |
* Returns a negative error number on failure, or the number of bytes |
| 369 |
* used / required on success. |
| 370 |
*/ |
| 371 |
int |
| 372 |
ext3_xattr_list(struct inode *inode, char *buffer, size_t buffer_size) |
| 373 |
{ |
| 374 |
struct buffer_head *bh = NULL; |
| 375 |
struct ext3_xattr_entry *entry; |
| 376 |
size_t size = 0; |
| 377 |
char *buf, *end; |
| 378 |
int error; |
| 379 |
|
| 380 |
ea_idebug(inode, "buffer=%p, buffer_size=%ld", |
| 381 |
buffer, (long)buffer_size); |
| 382 |
|
| 383 |
down_read(&EXT3_I(inode)->xattr_sem); |
| 384 |
error = 0; |
| 385 |
if (!EXT3_I(inode)->i_file_acl) |
| 386 |
goto cleanup; |
| 387 |
ea_idebug(inode, "reading block %d", EXT3_I(inode)->i_file_acl); |
| 388 |
bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl); |
| 389 |
error = -EIO; |
| 390 |
if (!bh) |
| 391 |
goto cleanup; |
| 392 |
ea_bdebug(bh, "b_count=%d, refcount=%d", |
| 393 |
atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); |
| 394 |
end = bh->b_data + bh->b_size; |
| 395 |
if (HDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) || |
| 396 |
HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| 397 |
bad_block: ext3_error(inode->i_sb, "ext3_xattr_list", |
| 398 |
"inode %ld: bad block %d", inode->i_ino, |
| 399 |
EXT3_I(inode)->i_file_acl); |
| 400 |
error = -EIO; |
| 401 |
goto cleanup; |
| 402 |
} |
| 403 |
/* compute the size required for the list of attribute names */ |
| 404 |
for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry); |
| 405 |
entry = EXT3_XATTR_NEXT(entry)) { |
| 406 |
struct ext3_xattr_handler *handler; |
| 407 |
struct ext3_xattr_entry *next = |
| 408 |
EXT3_XATTR_NEXT(entry); |
| 409 |
if ((char *)next >= end) |
| 410 |
goto bad_block; |
| 411 |
|
| 412 |
handler = ext3_xattr_handler(entry->e_name_index); |
| 413 |
if (handler) |
| 414 |
size += handler->list(NULL, inode, entry->e_name, |
| 415 |
entry->e_name_len); |
| 416 |
} |
| 417 |
|
| 418 |
if (ext3_xattr_cache_insert(bh)) |
| 419 |
ea_idebug(inode, "cache insert failed"); |
| 420 |
if (!buffer) { |
| 421 |
error = size; |
| 422 |
goto cleanup; |
| 423 |
} else { |
| 424 |
error = -ERANGE; |
| 425 |
if (size > buffer_size) |
| 426 |
goto cleanup; |
| 427 |
} |
| 428 |
|
| 429 |
/* list the attribute names */ |
| 430 |
buf = buffer; |
| 431 |
for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry); |
| 432 |
entry = EXT3_XATTR_NEXT(entry)) { |
| 433 |
struct ext3_xattr_handler *handler; |
| 434 |
|
| 435 |
handler = ext3_xattr_handler(entry->e_name_index); |
| 436 |
if (handler) |
| 437 |
buf += handler->list(buf, inode, entry->e_name, |
| 438 |
entry->e_name_len); |
| 439 |
} |
| 440 |
error = size; |
| 441 |
|
| 442 |
cleanup: |
| 443 |
brelse(bh); |
| 444 |
up_read(&EXT3_I(inode)->xattr_sem); |
| 445 |
|
| 446 |
return error; |
| 447 |
} |
| 448 |
|
| 449 |
/* |
| 450 |
* If the EXT3_FEATURE_COMPAT_EXT_ATTR feature of this file system is |
| 451 |
* not set, set it. |
| 452 |
*/ |
| 453 |
static void ext3_xattr_update_super_block(handle_t *handle, |
| 454 |
struct super_block *sb) |
| 455 |
{ |
| 456 |
if (EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR)) |
| 457 |
return; |
| 458 |
|
| 459 |
lock_super(sb); |
| 460 |
if (ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh) == 0) { |
| 461 |
EXT3_SB(sb)->s_es->s_feature_compat |= |
| 462 |
cpu_to_le32(EXT3_FEATURE_COMPAT_EXT_ATTR); |
| 463 |
sb->s_dirt = 1; |
| 464 |
ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh); |
| 465 |
} |
| 466 |
unlock_super(sb); |
| 467 |
} |
| 468 |
|
| 469 |
/* |
| 470 |
* ext3_xattr_set_handle() |
| 471 |
* |
| 472 |
* Create, replace or remove an extended attribute for this inode. Buffer |
| 473 |
* is NULL to remove an existing extended attribute, and non-NULL to |
| 474 |
* either replace an existing extended attribute, or create a new extended |
| 475 |
* attribute. The flags XATTR_REPLACE and XATTR_CREATE |
| 476 |
* specify that an extended attribute must exist and must not exist |
| 477 |
* previous to the call, respectively. |
| 478 |
* |
| 479 |
* Returns 0, or a negative error number on failure. |
| 480 |
*/ |
| 481 |
int |
| 482 |
ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, |
| 483 |
const char *name, const void *value, size_t value_len, |
| 484 |
int flags) |
| 485 |
{ |
| 486 |
struct super_block *sb = inode->i_sb; |
| 487 |
struct buffer_head *bh = NULL; |
| 488 |
struct ext3_xattr_header *header = NULL; |
| 489 |
struct ext3_xattr_entry *here, *last; |
| 490 |
size_t name_len, free, min_offs = sb->s_blocksize; |
| 491 |
int not_found = 1, error; |
| 492 |
char *end; |
| 493 |
|
| 494 |
/* |
| 495 |
* header -- Points either into bh, or to a temporarily |
| 496 |
* allocated buffer. |
| 497 |
* here -- The named entry found, or the place for inserting, within |
| 498 |
* the block pointed to by header. |
| 499 |
* last -- Points right after the last named entry within the block |
| 500 |
* pointed to by header. |
| 501 |
* min_offs -- The offset of the first value (values are aligned |
| 502 |
* towards the end of the block). |
| 503 |
* end -- Points right after the block pointed to by header. |
| 504 |
*/ |
| 505 |
|
| 506 |
ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", |
| 507 |
name_index, name, value, (long)value_len); |
| 508 |
|
| 509 |
if (IS_RDONLY(inode)) |
| 510 |
return -EROFS; |
| 511 |
if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
| 512 |
return -EPERM; |
| 513 |
if (value == NULL) |
| 514 |
value_len = 0; |
| 515 |
if (name == NULL) |
| 516 |
return -EINVAL; |
| 517 |
name_len = strlen(name); |
| 518 |
if (name_len > 255 || value_len > sb->s_blocksize) |
| 519 |
return -ERANGE; |
| 520 |
down_write(&EXT3_I(inode)->xattr_sem); |
| 521 |
if (EXT3_I(inode)->i_file_acl) { |
| 522 |
/* The inode already has an extended attribute block. */ |
| 523 |
bh = sb_bread(sb, EXT3_I(inode)->i_file_acl); |
| 524 |
error = -EIO; |
| 525 |
if (!bh) |
| 526 |
goto cleanup; |
| 527 |
ea_bdebug(bh, "b_count=%d, refcount=%d", |
| 528 |
atomic_read(&(bh->b_count)), |
| 529 |
le32_to_cpu(HDR(bh)->h_refcount)); |
| 530 |
header = HDR(bh); |
| 531 |
end = bh->b_data + bh->b_size; |
| 532 |
if (header->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) || |
| 533 |
header->h_blocks != cpu_to_le32(1)) { |
| 534 |
bad_block: ext3_error(sb, "ext3_xattr_set", |
| 535 |
"inode %ld: bad block %d", inode->i_ino, |
| 536 |
EXT3_I(inode)->i_file_acl); |
| 537 |
error = -EIO; |
| 538 |
goto cleanup; |
| 539 |
} |
| 540 |
/* Find the named attribute. */ |
| 541 |
here = FIRST_ENTRY(bh); |
| 542 |
while (!IS_LAST_ENTRY(here)) { |
| 543 |
struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(here); |
| 544 |
if ((char *)next >= end) |
| 545 |
goto bad_block; |
| 546 |
if (!here->e_value_block && here->e_value_size) { |
| 547 |
size_t offs = le16_to_cpu(here->e_value_offs); |
| 548 |
if (offs < min_offs) |
| 549 |
min_offs = offs; |
| 550 |
} |
| 551 |
not_found = name_index - here->e_name_index; |
| 552 |
if (!not_found) |
| 553 |
not_found = name_len - here->e_name_len; |
| 554 |
if (!not_found) |
| 555 |
not_found = memcmp(name, here->e_name,name_len); |
| 556 |
if (not_found <= 0) |
| 557 |
break; |
| 558 |
here = next; |
| 559 |
} |
| 560 |
last = here; |
| 561 |
/* We still need to compute min_offs and last. */ |
| 562 |
while (!IS_LAST_ENTRY(last)) { |
| 563 |
struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(last); |
| 564 |
if ((char *)next >= end) |
| 565 |
goto bad_block; |
| 566 |
if (!last->e_value_block && last->e_value_size) { |
| 567 |
size_t offs = le16_to_cpu(last->e_value_offs); |
| 568 |
if (offs < min_offs) |
| 569 |
min_offs = offs; |
| 570 |
} |
| 571 |
last = next; |
| 572 |
} |
| 573 |
|
| 574 |
/* Check whether we have enough space left. */ |
| 575 |
free = min_offs - ((char*)last - (char*)header) - sizeof(__u32); |
| 576 |
} else { |
| 577 |
/* We will use a new extended attribute block. */ |
| 578 |
free = sb->s_blocksize - |
| 579 |
sizeof(struct ext3_xattr_header) - sizeof(__u32); |
| 580 |
here = last = NULL; /* avoid gcc uninitialized warning. */ |
| 581 |
} |
| 582 |
|
| 583 |
if (not_found) { |
| 584 |
/* Request to remove a nonexistent attribute? */ |
| 585 |
error = -ENODATA; |
| 586 |
if (flags & XATTR_REPLACE) |
| 587 |
goto cleanup; |
| 588 |
error = 0; |
| 589 |
if (value == NULL) |
| 590 |
goto cleanup; |
| 591 |
} else { |
| 592 |
/* Request to create an existing attribute? */ |
| 593 |
error = -EEXIST; |
| 594 |
if (flags & XATTR_CREATE) |
| 595 |
goto cleanup; |
| 596 |
if (!here->e_value_block && here->e_value_size) { |
| 597 |
size_t size = le32_to_cpu(here->e_value_size); |
| 598 |
|
| 599 |
if (le16_to_cpu(here->e_value_offs) + size > |
| 600 |
sb->s_blocksize || size > sb->s_blocksize) |
| 601 |
goto bad_block; |
| 602 |
free += EXT3_XATTR_SIZE(size); |
| 603 |
} |
| 604 |
free += EXT3_XATTR_LEN(name_len); |
| 605 |
} |
| 606 |
error = -ENOSPC; |
| 607 |
if (free < EXT3_XATTR_LEN(name_len) + EXT3_XATTR_SIZE(value_len)) |
| 608 |
goto cleanup; |
| 609 |
|
| 610 |
/* Here we know that we can set the new attribute. */ |
| 611 |
|
| 612 |
if (header) { |
| 613 |
/* assert(header == HDR(bh)); */ |
| 614 |
if (header->h_refcount != cpu_to_le32(1)) |
| 615 |
goto skip_get_write_access; |
| 616 |
/* ext3_journal_get_write_access() requires an unlocked bh, |
| 617 |
which complicates things here. */ |
| 618 |
error = ext3_journal_get_write_access(handle, bh); |
| 619 |
if (error) |
| 620 |
goto cleanup; |
| 621 |
lock_buffer(bh); |
| 622 |
if (header->h_refcount == cpu_to_le32(1)) { |
| 623 |
ea_bdebug(bh, "modifying in-place"); |
| 624 |
ext3_xattr_cache_remove(bh); |
| 625 |
/* keep the buffer locked while modifying it. */ |
| 626 |
} else { |
| 627 |
int offset; |
| 628 |
|
| 629 |
unlock_buffer(bh); |
| 630 |
journal_release_buffer(handle, bh); |
| 631 |
skip_get_write_access: |
| 632 |
ea_bdebug(bh, "cloning"); |
| 633 |
header = kmalloc(bh->b_size, GFP_KERNEL); |
| 634 |
error = -ENOMEM; |
| 635 |
if (header == NULL) |
| 636 |
goto cleanup; |
| 637 |
memcpy(header, HDR(bh), bh->b_size); |
| 638 |
header->h_refcount = cpu_to_le32(1); |
| 639 |
offset = (char *)header - bh->b_data; |
| 640 |
here = ENTRY((char *)here + offset); |
| 641 |
last = ENTRY((char *)last + offset); |
| 642 |
} |
| 643 |
} else { |
| 644 |
/* Allocate a buffer where we construct the new block. */ |
| 645 |
header = kmalloc(sb->s_blocksize, GFP_KERNEL); |
| 646 |
error = -ENOMEM; |
| 647 |
if (header == NULL) |
| 648 |
goto cleanup; |
| 649 |
memset(header, 0, sb->s_blocksize); |
| 650 |
end = (char *)header + sb->s_blocksize; |
| 651 |
header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC); |
| 652 |
header->h_blocks = header->h_refcount = cpu_to_le32(1); |
| 653 |
last = here = ENTRY(header+1); |
| 654 |
} |
| 655 |
|
| 656 |
/* Iff we are modifying the block in-place, bh is locked here. */ |
| 657 |
|
| 658 |
if (not_found) { |
| 659 |
/* Insert the new name. */ |
| 660 |
int size = EXT3_XATTR_LEN(name_len); |
| 661 |
int rest = (char *)last - (char *)here; |
| 662 |
memmove((char *)here + size, here, rest); |
| 663 |
memset(here, 0, size); |
| 664 |
here->e_name_index = name_index; |
| 665 |
here->e_name_len = name_len; |
| 666 |
memcpy(here->e_name, name, name_len); |
| 667 |
} else { |
| 668 |
if (!here->e_value_block && here->e_value_size) { |
| 669 |
char *first_val = (char *)header + min_offs; |
| 670 |
int offs = le16_to_cpu(here->e_value_offs); |
| 671 |
char *val = (char *)header + offs; |
| 672 |
size_t size = EXT3_XATTR_SIZE( |
| 673 |
le32_to_cpu(here->e_value_size)); |
| 674 |
|
| 675 |
if (size == EXT3_XATTR_SIZE(value_len)) { |
| 676 |
/* The old and the new value have the same |
| 677 |
size. Just replace. */ |
| 678 |
here->e_value_size = cpu_to_le32(value_len); |
| 679 |
memset(val + size - EXT3_XATTR_PAD, 0, |
| 680 |
EXT3_XATTR_PAD); /* Clear pad bytes. */ |
| 681 |
memcpy(val, value, value_len); |
| 682 |
goto skip_replace; |
| 683 |
} |
| 684 |
|
| 685 |
/* Remove the old value. */ |
| 686 |
memmove(first_val + size, first_val, val - first_val); |
| 687 |
memset(first_val, 0, size); |
| 688 |
here->e_value_offs = 0; |
| 689 |
min_offs += size; |
| 690 |
|
| 691 |
/* Adjust all value offsets. */ |
| 692 |
last = ENTRY(header+1); |
| 693 |
while (!IS_LAST_ENTRY(last)) { |
| 694 |
int o = le16_to_cpu(last->e_value_offs); |
| 695 |
if (!last->e_value_block && o < offs) |
| 696 |
last->e_value_offs = |
| 697 |
cpu_to_le16(o + size); |
| 698 |
last = EXT3_XATTR_NEXT(last); |
| 699 |
} |
| 700 |
} |
| 701 |
if (value == NULL) { |
| 702 |
/* Remove the old name. */ |
| 703 |
int size = EXT3_XATTR_LEN(name_len); |
| 704 |
last = ENTRY((char *)last - size); |
| 705 |
memmove(here, (char*)here + size, |
| 706 |
(char*)last - (char*)here); |
| 707 |
memset(last, 0, size); |
| 708 |
} |
| 709 |
} |
| 710 |
|
| 711 |
if (value != NULL) { |
| 712 |
/* Insert the new value. */ |
| 713 |
here->e_value_size = cpu_to_le32(value_len); |
| 714 |
if (value_len) { |
| 715 |
size_t size = EXT3_XATTR_SIZE(value_len); |
| 716 |
char *val = (char *)header + min_offs - size; |
| 717 |
here->e_value_offs = |
| 718 |
cpu_to_le16((char *)val - (char *)header); |
| 719 |
memset(val + size - EXT3_XATTR_PAD, 0, |
| 720 |
EXT3_XATTR_PAD); /* Clear the pad bytes. */ |
| 721 |
memcpy(val, value, value_len); |
| 722 |
} |
| 723 |
} |
| 724 |
|
| 725 |
skip_replace: |
| 726 |
if (IS_LAST_ENTRY(ENTRY(header+1))) { |
| 727 |
/* This block is now empty. */ |
| 728 |
if (bh && header == HDR(bh)) |
| 729 |
unlock_buffer(bh); /* we were modifying in-place. */ |
| 730 |
error = ext3_xattr_set_handle2(handle, inode, bh, NULL); |
| 731 |
} else { |
| 732 |
ext3_xattr_rehash(header, here); |
| 733 |
if (bh && header == HDR(bh)) |
| 734 |
unlock_buffer(bh); /* we were modifying in-place. */ |
| 735 |
error = ext3_xattr_set_handle2(handle, inode, bh, header); |
| 736 |
} |
| 737 |
|
| 738 |
cleanup: |
| 739 |
brelse(bh); |
| 740 |
if (!(bh && header == HDR(bh))) |
| 741 |
kfree(header); |
| 742 |
up_write(&EXT3_I(inode)->xattr_sem); |
| 743 |
|
| 744 |
return error; |
| 745 |
} |
| 746 |
|
| 747 |
/* |
| 748 |
* Second half of ext3_xattr_set_handle(): Update the file system. |
| 749 |
*/ |
| 750 |
static int |
| 751 |
ext3_xattr_set_handle2(handle_t *handle, struct inode *inode, |
| 752 |
struct buffer_head *old_bh, struct ext3_xattr_header *header) |
| 753 |
{ |
| 754 |
struct super_block *sb = inode->i_sb; |
| 755 |
struct buffer_head *new_bh = NULL; |
| 756 |
int error; |
| 757 |
|
| 758 |
if (header) { |
| 759 |
new_bh = ext3_xattr_cache_find(handle, inode, header); |
| 760 |
if (new_bh) { |
| 761 |
/* We found an identical block in the cache. The |
| 762 |
* block returned is locked. The old block will |
| 763 |
* be released after updating the inode. |
| 764 |
*/ |
| 765 |
ea_bdebug(new_bh, "%s block %ld", |
| 766 |
(old_bh == new_bh) ? "keeping" : "reusing", |
| 767 |
new_bh->b_blocknr); |
| 768 |
|
| 769 |
error = -EDQUOT; |
| 770 |
/* How can we enforce the allocation? */ |
| 771 |
if (DQUOT_ALLOC_BLOCK(inode, 1)) { |
| 772 |
unlock_buffer(new_bh); |
| 773 |
journal_release_buffer(handle, new_bh); |
| 774 |
goto cleanup; |
| 775 |
} |
| 776 |
HDR(new_bh)->h_refcount = cpu_to_le32( |
| 777 |
le32_to_cpu(HDR(new_bh)->h_refcount) + 1); |
| 778 |
ea_bdebug(new_bh, "refcount now=%d", |
| 779 |
le32_to_cpu(HDR(new_bh)->h_refcount)); |
| 780 |
unlock_buffer(new_bh); |
| 781 |
} else if (old_bh && header == HDR(old_bh)) { |
| 782 |
/* Keep this block. No need to lock the block as we |
| 783 |
* don't need to change the reference count. */ |
| 784 |
new_bh = old_bh; |
| 785 |
get_bh(new_bh); |
| 786 |
ext3_xattr_cache_insert(new_bh); |
| 787 |
} else { |
| 788 |
/* We need to allocate a new block */ |
| 789 |
int goal = le32_to_cpu(EXT3_SB(inode->i_sb)->s_es-> |
| 790 |
s_first_data_block) + |
| 791 |
EXT3_I(inode)->i_block_group * |
| 792 |
EXT3_BLOCKS_PER_GROUP(inode->i_sb); |
| 793 |
/* How can we enforce the allocation? */ |
| 794 |
int block = ext3_new_block(handle, inode, goal, 0, 0, |
| 795 |
&error); |
| 796 |
if (error) |
| 797 |
goto cleanup; |
| 798 |
ea_idebug(inode, "creating block %d", block); |
| 799 |
|
| 800 |
new_bh = sb_getblk(sb, block); |
| 801 |
if (!new_bh) { |
| 802 |
getblk_failed: ext3_free_blocks(handle, inode, block, 1); |
| 803 |
error = -EIO; |
| 804 |
goto cleanup; |
| 805 |
} |
| 806 |
lock_buffer(new_bh); |
| 807 |
error = ext3_journal_get_create_access(handle, new_bh); |
| 808 |
if (error) { |
| 809 |
unlock_buffer(new_bh); |
| 810 |
goto getblk_failed; |
| 811 |
} |
| 812 |
memcpy(new_bh->b_data, header, new_bh->b_size); |
| 813 |
mark_buffer_uptodate(new_bh, 1); |
| 814 |
unlock_buffer(new_bh); |
| 815 |
ext3_xattr_cache_insert(new_bh); |
| 816 |
|
| 817 |
ext3_xattr_update_super_block(handle, sb); |
| 818 |
} |
| 819 |
error = ext3_journal_dirty_metadata(handle, new_bh); |
| 820 |
if (error) |
| 821 |
goto cleanup; |
| 822 |
} |
| 823 |
|
| 824 |
/* Update the inode. */ |
| 825 |
EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; |
| 826 |
inode->i_ctime = CURRENT_TIME; |
| 827 |
ext3_mark_inode_dirty(handle, inode); |
| 828 |
if (IS_SYNC(inode)) |
| 829 |
handle->h_sync = 1; |
| 830 |
|
| 831 |
error = 0; |
| 832 |
if (old_bh && old_bh != new_bh) { |
| 833 |
/* |
| 834 |
* If there was an old block and we are no longer using it, |
| 835 |
* release the old block. |
| 836 |
*/ |
| 837 |
|
| 838 |
error = ext3_journal_get_write_access(handle, old_bh); |
| 839 |
if (error) |
| 840 |
goto cleanup; |
| 841 |
lock_buffer(old_bh); |
| 842 |
if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) { |
| 843 |
/* Free the old block. */ |
| 844 |
ea_bdebug(old_bh, "freeing"); |
| 845 |
ext3_free_blocks(handle, inode, old_bh->b_blocknr, 1); |
| 846 |
|
| 847 |
/* ext3_forget() calls bforget() for us, but we |
| 848 |
let our caller release old_bh, so we need to |
| 849 |
duplicate the handle before. */ |
| 850 |
get_bh(old_bh); |
| 851 |
ext3_forget(handle, 1, inode, old_bh,old_bh->b_blocknr); |
| 852 |
} else { |
| 853 |
/* Decrement the refcount only. */ |
| 854 |
HDR(old_bh)->h_refcount = cpu_to_le32( |
| 855 |
le32_to_cpu(HDR(old_bh)->h_refcount) - 1); |
| 856 |
DQUOT_FREE_BLOCK(inode, 1); |
| 857 |
ext3_journal_dirty_metadata(handle, old_bh); |
| 858 |
ea_bdebug(old_bh, "refcount now=%d", |
| 859 |
le32_to_cpu(HDR(old_bh)->h_refcount)); |
| 860 |
} |
| 861 |
unlock_buffer(old_bh); |
| 862 |
} |
| 863 |
|
| 864 |
cleanup: |
| 865 |
brelse(new_bh); |
| 866 |
|
| 867 |
return error; |
| 868 |
} |
| 869 |
|
| 870 |
/* |
| 871 |
* ext3_xattr_set() |
| 872 |
* |
| 873 |
* Like ext3_xattr_set_handle, but start from an inode. This extended |
| 874 |
* attribute modification is a filesystem transaction by itself. |
| 875 |
* |
| 876 |
* Returns 0, or a negative error number on failure. |
| 877 |
*/ |
| 878 |
int |
| 879 |
ext3_xattr_set(struct inode *inode, int name_index, const char *name, |
| 880 |
const void *value, size_t value_len, int flags) |
| 881 |
{ |
| 882 |
handle_t *handle; |
| 883 |
int error, error2; |
| 884 |
|
| 885 |
lock_kernel(); |
| 886 |
handle = ext3_journal_start(inode, EXT3_XATTR_TRANS_BLOCKS); |
| 887 |
error = PTR_ERR(handle); |
| 888 |
if (IS_ERR(handle)) |
| 889 |
goto cleanup; |
| 890 |
error = ext3_xattr_set_handle(handle, inode, name_index, name, |
| 891 |
value, value_len, flags); |
| 892 |
error2 = ext3_journal_stop(handle, inode); |
| 893 |
if (!error) |
| 894 |
error = error2; |
| 895 |
|
| 896 |
cleanup: |
| 897 |
unlock_kernel(); |
| 898 |
return error; |
| 899 |
} |
| 900 |
|
| 901 |
/* |
| 902 |
* ext3_xattr_delete_inode() |
| 903 |
* |
| 904 |
* Free extended attribute resources associated with this inode. This |
| 905 |
* is called immediately before an inode is freed. |
| 906 |
*/ |
| 907 |
void |
| 908 |
ext3_xattr_delete_inode(handle_t *handle, struct inode *inode) |
| 909 |
{ |
| 910 |
struct buffer_head *bh = NULL; |
| 911 |
|
| 912 |
down_write(&EXT3_I(inode)->xattr_sem); |
| 913 |
if (!EXT3_I(inode)->i_file_acl) |
| 914 |
goto cleanup; |
| 915 |
bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl); |
| 916 |
if (!bh) { |
| 917 |
ext3_error(inode->i_sb, "ext3_xattr_delete_inode", |
| 918 |
"inode %ld: block %d read error", inode->i_ino, |
| 919 |
EXT3_I(inode)->i_file_acl); |
| 920 |
goto cleanup; |
| 921 |
} |
| 922 |
ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); |
| 923 |
if (HDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) || |
| 924 |
HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| 925 |
ext3_error(inode->i_sb, "ext3_xattr_delete_inode", |
| 926 |
"inode %ld: bad block %d", inode->i_ino, |
| 927 |
EXT3_I(inode)->i_file_acl); |
| 928 |
goto cleanup; |
| 929 |
} |
| 930 |
if (ext3_journal_get_write_access(handle, bh) != 0) |
| 931 |
goto cleanup; |
| 932 |
lock_buffer(bh); |
| 933 |
if (HDR(bh)->h_refcount == cpu_to_le32(1)) { |
| 934 |
ext3_xattr_cache_remove(bh); |
| 935 |
ext3_free_blocks(handle, inode, EXT3_I(inode)->i_file_acl, 1); |
| 936 |
|
| 937 |
/* ext3_forget() calls bforget() for us, but we release |
| 938 |
old_bh blow, so we need to duplicate the handle before. */ |
| 939 |
get_bh(bh); |
| 940 |
ext3_forget(handle, 1, inode, bh, EXT3_I(inode)->i_file_acl); |
| 941 |
} else { |
| 942 |
HDR(bh)->h_refcount = cpu_to_le32( |
| 943 |
le32_to_cpu(HDR(bh)->h_refcount) - 1); |
| 944 |
ext3_journal_dirty_metadata(handle, bh); |
| 945 |
if (IS_SYNC(inode)) |
| 946 |
handle->h_sync = 1; |
| 947 |
DQUOT_FREE_BLOCK(inode, 1); |
| 948 |
} |
| 949 |
ea_bdebug(bh, "refcount now=%d", le32_to_cpu(HDR(bh)->h_refcount)); |
| 950 |
unlock_buffer(bh); |
| 951 |
EXT3_I(inode)->i_file_acl = 0; |
| 952 |
|
| 953 |
cleanup: |
| 954 |
brelse(bh); |
| 955 |
up_write(&EXT3_I(inode)->xattr_sem); |
| 956 |
} |
| 957 |
|
| 958 |
/* |
| 959 |
* ext3_xattr_put_super() |
| 960 |
* |
| 961 |
* This is called when a file system is unmounted. |
| 962 |
*/ |
| 963 |
void |
| 964 |
ext3_xattr_put_super(struct super_block *sb) |
| 965 |
{ |
| 966 |
#ifdef CONFIG_EXT3_FS_XATTR_SHARING |
| 967 |
mb_cache_shrink(ext3_xattr_cache, sb->s_dev); |
| 968 |
#endif |
| 969 |
} |
| 970 |
|
| 971 |
#ifdef CONFIG_EXT3_FS_XATTR_SHARING |
| 972 |
|
| 973 |
/* |
| 974 |
* ext3_xattr_cache_insert() |
| 975 |
* |
| 976 |
* Create a new entry in the extended attribute cache, and insert |
| 977 |
* it unless such an entry is already in the cache. |
| 978 |
* |
| 979 |
* Returns 0, or a negative error number on failure. |
| 980 |
*/ |
| 981 |
static int |
| 982 |
ext3_xattr_cache_insert(struct buffer_head *bh) |
| 983 |
{ |
| 984 |
__u32 hash = le32_to_cpu(HDR(bh)->h_hash); |
| 985 |
struct mb_cache_entry *ce; |
| 986 |
int error; |
| 987 |
|
| 988 |
ce = mb_cache_entry_alloc(ext3_xattr_cache); |
| 989 |
if (!ce) |
| 990 |
return -ENOMEM; |
| 991 |
error = mb_cache_entry_insert(ce, bh->b_dev, bh->b_blocknr, &hash); |
| 992 |
if (error) { |
| 993 |
mb_cache_entry_free(ce); |
| 994 |
if (error == -EBUSY) { |
| 995 |
ea_bdebug(bh, "already in cache (%d cache entries)", |
| 996 |
atomic_read(&ext3_xattr_cache->c_entry_count)); |
| 997 |
error = 0; |
| 998 |
} |
| 999 |
} else { |
| 1000 |
ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash, |
| 1001 |
atomic_read(&ext3_xattr_cache->c_entry_count)); |
| 1002 |
mb_cache_entry_release(ce); |
| 1003 |
} |
| 1004 |
return error; |
| 1005 |
} |
| 1006 |
|
| 1007 |
/* |
| 1008 |
* ext3_xattr_cmp() |
| 1009 |
* |
| 1010 |
* Compare two extended attribute blocks for equality. |
| 1011 |
* |
| 1012 |
* Returns 0 if the blocks are equal, 1 if they differ, and |
| 1013 |
* a negative error number on errors. |
| 1014 |
*/ |
| 1015 |
static int |
| 1016 |
ext3_xattr_cmp(struct ext3_xattr_header *header1, |
| 1017 |
struct ext3_xattr_header *header2) |
| 1018 |
{ |
| 1019 |
struct ext3_xattr_entry *entry1, *entry2; |
| 1020 |
|
| 1021 |
entry1 = ENTRY(header1+1); |
| 1022 |
entry2 = ENTRY(header2+1); |
| 1023 |
while (!IS_LAST_ENTRY(entry1)) { |
| 1024 |
if (IS_LAST_ENTRY(entry2)) |
| 1025 |
return 1; |
| 1026 |
if (entry1->e_hash != entry2->e_hash || |
| 1027 |
entry1->e_name_len != entry2->e_name_len || |
| 1028 |
entry1->e_value_size != entry2->e_value_size || |
| 1029 |
memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) |
| 1030 |
return 1; |
| 1031 |
if (entry1->e_value_block != 0 || entry2->e_value_block != 0) |
| 1032 |
return -EIO; |
| 1033 |
if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), |
| 1034 |
(char *)header2 + le16_to_cpu(entry2->e_value_offs), |
| 1035 |
le32_to_cpu(entry1->e_value_size))) |
| 1036 |
return 1; |
| 1037 |
|
| 1038 |
entry1 = EXT3_XATTR_NEXT(entry1); |
| 1039 |
entry2 = EXT3_XATTR_NEXT(entry2); |
| 1040 |
} |
| 1041 |
if (!IS_LAST_ENTRY(entry2)) |
| 1042 |
return 1; |
| 1043 |
return 0; |
| 1044 |
} |
| 1045 |
|
| 1046 |
/* |
| 1047 |
* ext3_xattr_cache_find() |
| 1048 |
* |
| 1049 |
* Find an identical extended attribute block. |
| 1050 |
* |
| 1051 |
* Returns a pointer to the block found, or NULL if such a block was |
| 1052 |
* not found or an error occurred. |
| 1053 |
*/ |
| 1054 |
static struct buffer_head * |
| 1055 |
ext3_xattr_cache_find(handle_t *handle, struct inode *inode, |
| 1056 |
struct ext3_xattr_header *header) |
| 1057 |
{ |
| 1058 |
__u32 hash = le32_to_cpu(header->h_hash); |
| 1059 |
struct mb_cache_entry *ce; |
| 1060 |
|
| 1061 |
if (!header->h_hash) |
| 1062 |
return NULL; /* never share */ |
| 1063 |
ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); |
| 1064 |
ce = mb_cache_entry_find_first(ext3_xattr_cache, 0, inode->i_dev, hash); |
| 1065 |
while (ce) { |
| 1066 |
struct buffer_head *bh = sb_bread(inode->i_sb, ce->e_block); |
| 1067 |
|
| 1068 |
if (!bh) { |
| 1069 |
ext3_error(inode->i_sb, "ext3_xattr_cache_find", |
| 1070 |
"inode %ld: block %ld read error", |
| 1071 |
inode->i_ino, ce->e_block); |
| 1072 |
} else { |
| 1073 |
/* ext3_journal_get_write_access() requires an unlocked |
| 1074 |
bh, which complicates things here. */ |
| 1075 |
if (ext3_journal_get_write_access(handle, bh) != 0) |
| 1076 |
return NULL; |
| 1077 |
lock_buffer(bh); |
| 1078 |
if (le32_to_cpu(HDR(bh)->h_refcount) > |
| 1079 |
EXT3_XATTR_REFCOUNT_MAX) { |
| 1080 |
ea_idebug(inode, "block %ld refcount %d>%d", |
| 1081 |
ce->e_block, |
| 1082 |
le32_to_cpu(HDR(bh)->h_refcount), |
| 1083 |
EXT3_XATTR_REFCOUNT_MAX); |
| 1084 |
} else if (!ext3_xattr_cmp(header, HDR(bh))) { |
| 1085 |
ea_bdebug(bh, "b_count=%d", |
| 1086 |
atomic_read(&(bh->b_count))); |
| 1087 |
mb_cache_entry_release(ce); |
| 1088 |
/* buffer will be unlocked by caller */ |
| 1089 |
return bh; |
| 1090 |
} |
| 1091 |
unlock_buffer(bh); |
| 1092 |
journal_release_buffer(handle, bh); |
| 1093 |
brelse(bh); |
| 1094 |
} |
| 1095 |
ce = mb_cache_entry_find_next(ce, 0, inode->i_dev, hash); |
| 1096 |
} |
| 1097 |
return NULL; |
| 1098 |
} |
| 1099 |
|
| 1100 |
/* |
| 1101 |
* ext3_xattr_cache_remove() |
| 1102 |
* |
| 1103 |
* Remove the cache entry of a block from the cache. Called when a |
| 1104 |
* block becomes invalid. |
| 1105 |
*/ |
| 1106 |
static void |
| 1107 |
ext3_xattr_cache_remove(struct buffer_head *bh) |
| 1108 |
{ |
| 1109 |
struct mb_cache_entry *ce; |
| 1110 |
|
| 1111 |
ce = mb_cache_entry_get(ext3_xattr_cache, bh->b_dev, bh->b_blocknr); |
| 1112 |
if (ce) { |
| 1113 |
ea_bdebug(bh, "removing (%d cache entries remaining)", |
| 1114 |
atomic_read(&ext3_xattr_cache->c_entry_count)-1); |
| 1115 |
mb_cache_entry_free(ce); |
| 1116 |
} else |
| 1117 |
ea_bdebug(bh, "no cache entry"); |
| 1118 |
} |
| 1119 |
|
| 1120 |
#define NAME_HASH_SHIFT 5 |
| 1121 |
#define VALUE_HASH_SHIFT 16 |
| 1122 |
|
| 1123 |
/* |
| 1124 |
* ext3_xattr_hash_entry() |
| 1125 |
* |
| 1126 |
* Compute the hash of an extended attribute. |
| 1127 |
*/ |
| 1128 |
static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header, |
| 1129 |
struct ext3_xattr_entry *entry) |
| 1130 |
{ |
| 1131 |
__u32 hash = 0; |
| 1132 |
char *name = entry->e_name; |
| 1133 |
int n; |
| 1134 |
|
| 1135 |
for (n=0; n < entry->e_name_len; n++) { |
| 1136 |
hash = (hash << NAME_HASH_SHIFT) ^ |
| 1137 |
(hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ |
| 1138 |
*name++; |
| 1139 |
} |
| 1140 |
|
| 1141 |
if (entry->e_value_block == 0 && entry->e_value_size != 0) { |
| 1142 |
__u32 *value = (__u32 *)((char *)header + |
| 1143 |
le16_to_cpu(entry->e_value_offs)); |
| 1144 |
for (n = (le32_to_cpu(entry->e_value_size) + |
| 1145 |
EXT3_XATTR_ROUND) >> EXT3_XATTR_PAD_BITS; n; n--) { |
| 1146 |
hash = (hash << VALUE_HASH_SHIFT) ^ |
| 1147 |
(hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ |
| 1148 |
le32_to_cpu(*value++); |
| 1149 |
} |
| 1150 |
} |
| 1151 |
entry->e_hash = cpu_to_le32(hash); |
| 1152 |
} |
| 1153 |
|
| 1154 |
#undef NAME_HASH_SHIFT |
| 1155 |
#undef VALUE_HASH_SHIFT |
| 1156 |
|
| 1157 |
#define BLOCK_HASH_SHIFT 16 |
| 1158 |
|
| 1159 |
/* |
| 1160 |
* ext3_xattr_rehash() |
| 1161 |
* |
| 1162 |
* Re-compute the extended attribute hash value after an entry has changed. |
| 1163 |
*/ |
| 1164 |
static void ext3_xattr_rehash(struct ext3_xattr_header *header, |
| 1165 |
struct ext3_xattr_entry *entry) |
| 1166 |
{ |
| 1167 |
struct ext3_xattr_entry *here; |
| 1168 |
__u32 hash = 0; |
| 1169 |
|
| 1170 |
ext3_xattr_hash_entry(header, entry); |
| 1171 |
here = ENTRY(header+1); |
| 1172 |
while (!IS_LAST_ENTRY(here)) { |
| 1173 |
if (!here->e_hash) { |
| 1174 |
/* Block is not shared if an entry's hash value == 0 */ |
| 1175 |
hash = 0; |
| 1176 |
break; |
| 1177 |
} |
| 1178 |
hash = (hash << BLOCK_HASH_SHIFT) ^ |
| 1179 |
(hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ |
| 1180 |
le32_to_cpu(here->e_hash); |
| 1181 |
here = EXT3_XATTR_NEXT(here); |
| 1182 |
} |
| 1183 |
header->h_hash = cpu_to_le32(hash); |
| 1184 |
} |
| 1185 |
|
| 1186 |
#undef BLOCK_HASH_SHIFT |
| 1187 |
|
| 1188 |
int __init |
| 1189 |
init_ext3_xattr(void) |
| 1190 |
{ |
| 1191 |
ext3_xattr_cache = mb_cache_create("ext3_xattr", NULL, |
| 1192 |
sizeof(struct mb_cache_entry) + |
| 1193 |
sizeof(struct mb_cache_entry_index), 1, 61); |
| 1194 |
if (!ext3_xattr_cache) |
| 1195 |
return -ENOMEM; |
| 1196 |
|
| 1197 |
return 0; |
| 1198 |
} |
| 1199 |
|
| 1200 |
void |
| 1201 |
exit_ext3_xattr(void) |
| 1202 |
{ |
| 1203 |
if (ext3_xattr_cache) |
| 1204 |
mb_cache_destroy(ext3_xattr_cache); |
| 1205 |
ext3_xattr_cache = NULL; |
| 1206 |
} |
| 1207 |
|
| 1208 |
#else /* CONFIG_EXT3_FS_XATTR_SHARING */ |
| 1209 |
|
| 1210 |
int __init |
| 1211 |
init_ext3_xattr(void) |
| 1212 |
{ |
| 1213 |
return 0; |
| 1214 |
} |
| 1215 |
|
| 1216 |
void |
| 1217 |
exit_ext3_xattr(void) |
| 1218 |
{ |
| 1219 |
} |
| 1220 |
|
| 1221 |
#endif /* CONFIG_EXT3_FS_XATTR_SHARING */ |
