| 1 | /* |
| 2 | * (C) 1997 Linus Torvalds |
| 3 | * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation) |
| 4 | */ |
| 5 | #include <linux/export.h> |
| 6 | #include <linux/fs.h> |
| 7 | #include <linux/mm.h> |
| 8 | #include <linux/backing-dev.h> |
| 9 | #include <linux/hash.h> |
| 10 | #include <linux/swap.h> |
| 11 | #include <linux/security.h> |
| 12 | #include <linux/cdev.h> |
| 13 | #include <linux/bootmem.h> |
| 14 | #include <linux/fsnotify.h> |
| 15 | #include <linux/mount.h> |
| 16 | #include <linux/posix_acl.h> |
| 17 | #include <linux/prefetch.h> |
| 18 | #include <linux/buffer_head.h> /* for inode_has_buffers */ |
| 19 | #include <linux/ratelimit.h> |
| 20 | #include "internal.h" |
| 21 | |
| 22 | /* |
| 23 | * Inode locking rules: |
| 24 | * |
| 25 | * inode->i_lock protects: |
| 26 | * inode->i_state, inode->i_hash, __iget() |
| 27 | * inode->i_sb->s_inode_lru_lock protects: |
| 28 | * inode->i_sb->s_inode_lru, inode->i_lru |
| 29 | * inode_sb_list_lock protects: |
| 30 | * sb->s_inodes, inode->i_sb_list |
| 31 | * bdi->wb.list_lock protects: |
| 32 | * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list |
| 33 | * inode_hash_lock protects: |
| 34 | * inode_hashtable, inode->i_hash |
| 35 | * |
| 36 | * Lock ordering: |
| 37 | * |
| 38 | * inode_sb_list_lock |
| 39 | * inode->i_lock |
| 40 | * inode->i_sb->s_inode_lru_lock |
| 41 | * |
| 42 | * bdi->wb.list_lock |
| 43 | * inode->i_lock |
| 44 | * |
| 45 | * inode_hash_lock |
| 46 | * inode_sb_list_lock |
| 47 | * inode->i_lock |
| 48 | * |
| 49 | * iunique_lock |
| 50 | * inode_hash_lock |
| 51 | */ |
| 52 | |
| 53 | static unsigned int i_hash_mask __read_mostly; |
| 54 | static unsigned int i_hash_shift __read_mostly; |
| 55 | static struct hlist_head *inode_hashtable __read_mostly; |
| 56 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
| 57 | |
| 58 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock); |
| 59 | |
| 60 | /* |
| 61 | * Empty aops. Can be used for the cases where the user does not |
| 62 | * define any of the address_space operations. |
| 63 | */ |
| 64 | const struct address_space_operations empty_aops = { |
| 65 | }; |
| 66 | EXPORT_SYMBOL(empty_aops); |
| 67 | |
| 68 | /* |
| 69 | * Statistics gathering.. |
| 70 | */ |
| 71 | struct inodes_stat_t inodes_stat; |
| 72 | |
| 73 | static DEFINE_PER_CPU(unsigned int, nr_inodes); |
| 74 | static DEFINE_PER_CPU(unsigned int, nr_unused); |
| 75 | |
| 76 | static struct kmem_cache *inode_cachep __read_mostly; |
| 77 | |
| 78 | static int get_nr_inodes(void) |
| 79 | { |
| 80 | int i; |
| 81 | int sum = 0; |
| 82 | for_each_possible_cpu(i) |
| 83 | sum += per_cpu(nr_inodes, i); |
| 84 | return sum < 0 ? 0 : sum; |
| 85 | } |
| 86 | |
| 87 | static inline int get_nr_inodes_unused(void) |
| 88 | { |
| 89 | int i; |
| 90 | int sum = 0; |
| 91 | for_each_possible_cpu(i) |
| 92 | sum += per_cpu(nr_unused, i); |
| 93 | return sum < 0 ? 0 : sum; |
| 94 | } |
| 95 | |
| 96 | int get_nr_dirty_inodes(void) |
| 97 | { |
| 98 | /* not actually dirty inodes, but a wild approximation */ |
| 99 | int nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
| 100 | return nr_dirty > 0 ? nr_dirty : 0; |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Handle nr_inode sysctl |
| 105 | */ |
| 106 | #ifdef CONFIG_SYSCTL |
| 107 | int proc_nr_inodes(ctl_table *table, int write, |
| 108 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 109 | { |
| 110 | inodes_stat.nr_inodes = get_nr_inodes(); |
| 111 | inodes_stat.nr_unused = get_nr_inodes_unused(); |
| 112 | return proc_dointvec(table, write, buffer, lenp, ppos); |
| 113 | } |
| 114 | #endif |
| 115 | |
| 116 | /** |
| 117 | * inode_init_always - perform inode structure intialisation |
| 118 | * @sb: superblock inode belongs to |
| 119 | * @inode: inode to initialise |
| 120 | * |
| 121 | * These are initializations that need to be done on every inode |
| 122 | * allocation as the fields are not initialised by slab allocation. |
| 123 | */ |
| 124 | int inode_init_always(struct super_block *sb, struct inode *inode) |
| 125 | { |
| 126 | static const struct inode_operations empty_iops; |
| 127 | static const struct file_operations empty_fops; |
| 128 | struct address_space *const mapping = &inode->i_data; |
| 129 | |
| 130 | inode->i_sb = sb; |
| 131 | inode->i_blkbits = sb->s_blocksize_bits; |
| 132 | inode->i_flags = 0; |
| 133 | atomic_set(&inode->i_count, 1); |
| 134 | inode->i_op = &empty_iops; |
| 135 | inode->i_fop = &empty_fops; |
| 136 | inode->__i_nlink = 1; |
| 137 | inode->i_opflags = 0; |
| 138 | i_uid_write(inode, 0); |
| 139 | i_gid_write(inode, 0); |
| 140 | atomic_set(&inode->i_writecount, 0); |
| 141 | inode->i_size = 0; |
| 142 | inode->i_blocks = 0; |
| 143 | inode->i_bytes = 0; |
| 144 | inode->i_generation = 0; |
| 145 | #ifdef CONFIG_QUOTA |
| 146 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
| 147 | #endif |
| 148 | inode->i_pipe = NULL; |
| 149 | inode->i_bdev = NULL; |
| 150 | inode->i_cdev = NULL; |
| 151 | inode->i_rdev = 0; |
| 152 | inode->dirtied_when = 0; |
| 153 | |
| 154 | if (security_inode_alloc(inode)) |
| 155 | goto out; |
| 156 | spin_lock_init(&inode->i_lock); |
| 157 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
| 158 | |
| 159 | mutex_init(&inode->i_mutex); |
| 160 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
| 161 | |
| 162 | atomic_set(&inode->i_dio_count, 0); |
| 163 | |
| 164 | mapping->a_ops = &empty_aops; |
| 165 | mapping->host = inode; |
| 166 | mapping->flags = 0; |
| 167 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
| 168 | mapping->private_data = NULL; |
| 169 | mapping->backing_dev_info = &default_backing_dev_info; |
| 170 | mapping->writeback_index = 0; |
| 171 | |
| 172 | /* |
| 173 | * If the block_device provides a backing_dev_info for client |
| 174 | * inodes then use that. Otherwise the inode share the bdev's |
| 175 | * backing_dev_info. |
| 176 | */ |
| 177 | if (sb->s_bdev) { |
| 178 | struct backing_dev_info *bdi; |
| 179 | |
| 180 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
| 181 | mapping->backing_dev_info = bdi; |
| 182 | } |
| 183 | inode->i_private = NULL; |
| 184 | inode->i_mapping = mapping; |
| 185 | INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ |
| 186 | #ifdef CONFIG_FS_POSIX_ACL |
| 187 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
| 188 | #endif |
| 189 | |
| 190 | #ifdef CONFIG_FSNOTIFY |
| 191 | inode->i_fsnotify_mask = 0; |
| 192 | #endif |
| 193 | |
| 194 | this_cpu_inc(nr_inodes); |
| 195 | |
| 196 | return 0; |
| 197 | out: |
| 198 | return -ENOMEM; |
| 199 | } |
| 200 | EXPORT_SYMBOL(inode_init_always); |
| 201 | |
| 202 | static struct inode *alloc_inode(struct super_block *sb) |
| 203 | { |
| 204 | struct inode *inode; |
| 205 | |
| 206 | if (sb->s_op->alloc_inode) |
| 207 | inode = sb->s_op->alloc_inode(sb); |
| 208 | else |
| 209 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
| 210 | |
| 211 | if (!inode) |
| 212 | return NULL; |
| 213 | |
| 214 | if (unlikely(inode_init_always(sb, inode))) { |
| 215 | if (inode->i_sb->s_op->destroy_inode) |
| 216 | inode->i_sb->s_op->destroy_inode(inode); |
| 217 | else |
| 218 | kmem_cache_free(inode_cachep, inode); |
| 219 | return NULL; |
| 220 | } |
| 221 | |
| 222 | return inode; |
| 223 | } |
| 224 | |
| 225 | void free_inode_nonrcu(struct inode *inode) |
| 226 | { |
| 227 | kmem_cache_free(inode_cachep, inode); |
| 228 | } |
| 229 | EXPORT_SYMBOL(free_inode_nonrcu); |
| 230 | |
| 231 | void __destroy_inode(struct inode *inode) |
| 232 | { |
| 233 | BUG_ON(inode_has_buffers(inode)); |
| 234 | security_inode_free(inode); |
| 235 | fsnotify_inode_delete(inode); |
| 236 | if (!inode->i_nlink) { |
| 237 | WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); |
| 238 | atomic_long_dec(&inode->i_sb->s_remove_count); |
| 239 | } |
| 240 | |
| 241 | #ifdef CONFIG_FS_POSIX_ACL |
| 242 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
| 243 | posix_acl_release(inode->i_acl); |
| 244 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
| 245 | posix_acl_release(inode->i_default_acl); |
| 246 | #endif |
| 247 | this_cpu_dec(nr_inodes); |
| 248 | } |
| 249 | EXPORT_SYMBOL(__destroy_inode); |
| 250 | |
| 251 | static void i_callback(struct rcu_head *head) |
| 252 | { |
| 253 | struct inode *inode = container_of(head, struct inode, i_rcu); |
| 254 | kmem_cache_free(inode_cachep, inode); |
| 255 | } |
| 256 | |
| 257 | static void destroy_inode(struct inode *inode) |
| 258 | { |
| 259 | BUG_ON(!list_empty(&inode->i_lru)); |
| 260 | __destroy_inode(inode); |
| 261 | if (inode->i_sb->s_op->destroy_inode) |
| 262 | inode->i_sb->s_op->destroy_inode(inode); |
| 263 | else |
| 264 | call_rcu(&inode->i_rcu, i_callback); |
| 265 | } |
| 266 | |
| 267 | /** |
| 268 | * drop_nlink - directly drop an inode's link count |
| 269 | * @inode: inode |
| 270 | * |
| 271 | * This is a low-level filesystem helper to replace any |
| 272 | * direct filesystem manipulation of i_nlink. In cases |
| 273 | * where we are attempting to track writes to the |
| 274 | * filesystem, a decrement to zero means an imminent |
| 275 | * write when the file is truncated and actually unlinked |
| 276 | * on the filesystem. |
| 277 | */ |
| 278 | void drop_nlink(struct inode *inode) |
| 279 | { |
| 280 | WARN_ON(inode->i_nlink == 0); |
| 281 | inode->__i_nlink--; |
| 282 | if (!inode->i_nlink) |
| 283 | atomic_long_inc(&inode->i_sb->s_remove_count); |
| 284 | } |
| 285 | EXPORT_SYMBOL(drop_nlink); |
| 286 | |
| 287 | /** |
| 288 | * clear_nlink - directly zero an inode's link count |
| 289 | * @inode: inode |
| 290 | * |
| 291 | * This is a low-level filesystem helper to replace any |
| 292 | * direct filesystem manipulation of i_nlink. See |
| 293 | * drop_nlink() for why we care about i_nlink hitting zero. |
| 294 | */ |
| 295 | void clear_nlink(struct inode *inode) |
| 296 | { |
| 297 | if (inode->i_nlink) { |
| 298 | inode->__i_nlink = 0; |
| 299 | atomic_long_inc(&inode->i_sb->s_remove_count); |
| 300 | } |
| 301 | } |
| 302 | EXPORT_SYMBOL(clear_nlink); |
| 303 | |
| 304 | /** |
| 305 | * set_nlink - directly set an inode's link count |
| 306 | * @inode: inode |
| 307 | * @nlink: new nlink (should be non-zero) |
| 308 | * |
| 309 | * This is a low-level filesystem helper to replace any |
| 310 | * direct filesystem manipulation of i_nlink. |
| 311 | */ |
| 312 | void set_nlink(struct inode *inode, unsigned int nlink) |
| 313 | { |
| 314 | if (!nlink) { |
| 315 | clear_nlink(inode); |
| 316 | } else { |
| 317 | /* Yes, some filesystems do change nlink from zero to one */ |
| 318 | if (inode->i_nlink == 0) |
| 319 | atomic_long_dec(&inode->i_sb->s_remove_count); |
| 320 | |
| 321 | inode->__i_nlink = nlink; |
| 322 | } |
| 323 | } |
| 324 | EXPORT_SYMBOL(set_nlink); |
| 325 | |
| 326 | /** |
| 327 | * inc_nlink - directly increment an inode's link count |
| 328 | * @inode: inode |
| 329 | * |
| 330 | * This is a low-level filesystem helper to replace any |
| 331 | * direct filesystem manipulation of i_nlink. Currently, |
| 332 | * it is only here for parity with dec_nlink(). |
| 333 | */ |
| 334 | void inc_nlink(struct inode *inode) |
| 335 | { |
| 336 | if (WARN_ON(inode->i_nlink == 0)) |
| 337 | atomic_long_dec(&inode->i_sb->s_remove_count); |
| 338 | |
| 339 | inode->__i_nlink++; |
| 340 | } |
| 341 | EXPORT_SYMBOL(inc_nlink); |
| 342 | |
| 343 | void address_space_init_once(struct address_space *mapping) |
| 344 | { |
| 345 | memset(mapping, 0, sizeof(*mapping)); |
| 346 | INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); |
| 347 | spin_lock_init(&mapping->tree_lock); |
| 348 | mutex_init(&mapping->i_mmap_mutex); |
| 349 | INIT_LIST_HEAD(&mapping->private_list); |
| 350 | spin_lock_init(&mapping->private_lock); |
| 351 | mapping->i_mmap = RB_ROOT; |
| 352 | INIT_LIST_HEAD(&mapping->i_mmap_nonlinear); |
| 353 | } |
| 354 | EXPORT_SYMBOL(address_space_init_once); |
| 355 | |
| 356 | /* |
| 357 | * These are initializations that only need to be done |
| 358 | * once, because the fields are idempotent across use |
| 359 | * of the inode, so let the slab aware of that. |
| 360 | */ |
| 361 | void inode_init_once(struct inode *inode) |
| 362 | { |
| 363 | memset(inode, 0, sizeof(*inode)); |
| 364 | INIT_HLIST_NODE(&inode->i_hash); |
| 365 | INIT_LIST_HEAD(&inode->i_devices); |
| 366 | INIT_LIST_HEAD(&inode->i_wb_list); |
| 367 | INIT_LIST_HEAD(&inode->i_lru); |
| 368 | address_space_init_once(&inode->i_data); |
| 369 | i_size_ordered_init(inode); |
| 370 | #ifdef CONFIG_FSNOTIFY |
| 371 | INIT_HLIST_HEAD(&inode->i_fsnotify_marks); |
| 372 | #endif |
| 373 | } |
| 374 | EXPORT_SYMBOL(inode_init_once); |
| 375 | |
| 376 | static void init_once(void *foo) |
| 377 | { |
| 378 | struct inode *inode = (struct inode *) foo; |
| 379 | |
| 380 | inode_init_once(inode); |
| 381 | } |
| 382 | |
| 383 | /* |
| 384 | * inode->i_lock must be held |
| 385 | */ |
| 386 | void __iget(struct inode *inode) |
| 387 | { |
| 388 | atomic_inc(&inode->i_count); |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * get additional reference to inode; caller must already hold one. |
| 393 | */ |
| 394 | void ihold(struct inode *inode) |
| 395 | { |
| 396 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
| 397 | } |
| 398 | EXPORT_SYMBOL(ihold); |
| 399 | |
| 400 | static void inode_lru_list_add(struct inode *inode) |
| 401 | { |
| 402 | spin_lock(&inode->i_sb->s_inode_lru_lock); |
| 403 | if (list_empty(&inode->i_lru)) { |
| 404 | list_add(&inode->i_lru, &inode->i_sb->s_inode_lru); |
| 405 | inode->i_sb->s_nr_inodes_unused++; |
| 406 | this_cpu_inc(nr_unused); |
| 407 | } |
| 408 | spin_unlock(&inode->i_sb->s_inode_lru_lock); |
| 409 | } |
| 410 | |
| 411 | /* |
| 412 | * Add inode to LRU if needed (inode is unused and clean). |
| 413 | * |
| 414 | * Needs inode->i_lock held. |
| 415 | */ |
| 416 | void inode_add_lru(struct inode *inode) |
| 417 | { |
| 418 | if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) && |
| 419 | !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE) |
| 420 | inode_lru_list_add(inode); |
| 421 | } |
| 422 | |
| 423 | |
| 424 | static void inode_lru_list_del(struct inode *inode) |
| 425 | { |
| 426 | spin_lock(&inode->i_sb->s_inode_lru_lock); |
| 427 | if (!list_empty(&inode->i_lru)) { |
| 428 | list_del_init(&inode->i_lru); |
| 429 | inode->i_sb->s_nr_inodes_unused--; |
| 430 | this_cpu_dec(nr_unused); |
| 431 | } |
| 432 | spin_unlock(&inode->i_sb->s_inode_lru_lock); |
| 433 | } |
| 434 | |
| 435 | /** |
| 436 | * inode_sb_list_add - add inode to the superblock list of inodes |
| 437 | * @inode: inode to add |
| 438 | */ |
| 439 | void inode_sb_list_add(struct inode *inode) |
| 440 | { |
| 441 | spin_lock(&inode_sb_list_lock); |
| 442 | list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
| 443 | spin_unlock(&inode_sb_list_lock); |
| 444 | } |
| 445 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
| 446 | |
| 447 | static inline void inode_sb_list_del(struct inode *inode) |
| 448 | { |
| 449 | if (!list_empty(&inode->i_sb_list)) { |
| 450 | spin_lock(&inode_sb_list_lock); |
| 451 | list_del_init(&inode->i_sb_list); |
| 452 | spin_unlock(&inode_sb_list_lock); |
| 453 | } |
| 454 | } |
| 455 | |
| 456 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
| 457 | { |
| 458 | unsigned long tmp; |
| 459 | |
| 460 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
| 461 | L1_CACHE_BYTES; |
| 462 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
| 463 | return tmp & i_hash_mask; |
| 464 | } |
| 465 | |
| 466 | /** |
| 467 | * __insert_inode_hash - hash an inode |
| 468 | * @inode: unhashed inode |
| 469 | * @hashval: unsigned long value used to locate this object in the |
| 470 | * inode_hashtable. |
| 471 | * |
| 472 | * Add an inode to the inode hash for this superblock. |
| 473 | */ |
| 474 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
| 475 | { |
| 476 | struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
| 477 | |
| 478 | spin_lock(&inode_hash_lock); |
| 479 | spin_lock(&inode->i_lock); |
| 480 | hlist_add_head(&inode->i_hash, b); |
| 481 | spin_unlock(&inode->i_lock); |
| 482 | spin_unlock(&inode_hash_lock); |
| 483 | } |
| 484 | EXPORT_SYMBOL(__insert_inode_hash); |
| 485 | |
| 486 | /** |
| 487 | * __remove_inode_hash - remove an inode from the hash |
| 488 | * @inode: inode to unhash |
| 489 | * |
| 490 | * Remove an inode from the superblock. |
| 491 | */ |
| 492 | void __remove_inode_hash(struct inode *inode) |
| 493 | { |
| 494 | spin_lock(&inode_hash_lock); |
| 495 | spin_lock(&inode->i_lock); |
| 496 | hlist_del_init(&inode->i_hash); |
| 497 | spin_unlock(&inode->i_lock); |
| 498 | spin_unlock(&inode_hash_lock); |
| 499 | } |
| 500 | EXPORT_SYMBOL(__remove_inode_hash); |
| 501 | |
| 502 | void clear_inode(struct inode *inode) |
| 503 | { |
| 504 | might_sleep(); |
| 505 | /* |
| 506 | * We have to cycle tree_lock here because reclaim can be still in the |
| 507 | * process of removing the last page (in __delete_from_page_cache()) |
| 508 | * and we must not free mapping under it. |
| 509 | */ |
| 510 | spin_lock_irq(&inode->i_data.tree_lock); |
| 511 | BUG_ON(inode->i_data.nrpages); |
| 512 | spin_unlock_irq(&inode->i_data.tree_lock); |
| 513 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
| 514 | BUG_ON(!(inode->i_state & I_FREEING)); |
| 515 | BUG_ON(inode->i_state & I_CLEAR); |
| 516 | /* don't need i_lock here, no concurrent mods to i_state */ |
| 517 | inode->i_state = I_FREEING | I_CLEAR; |
| 518 | } |
| 519 | EXPORT_SYMBOL(clear_inode); |
| 520 | |
| 521 | /* |
| 522 | * Free the inode passed in, removing it from the lists it is still connected |
| 523 | * to. We remove any pages still attached to the inode and wait for any IO that |
| 524 | * is still in progress before finally destroying the inode. |
| 525 | * |
| 526 | * An inode must already be marked I_FREEING so that we avoid the inode being |
| 527 | * moved back onto lists if we race with other code that manipulates the lists |
| 528 | * (e.g. writeback_single_inode). The caller is responsible for setting this. |
| 529 | * |
| 530 | * An inode must already be removed from the LRU list before being evicted from |
| 531 | * the cache. This should occur atomically with setting the I_FREEING state |
| 532 | * flag, so no inodes here should ever be on the LRU when being evicted. |
| 533 | */ |
| 534 | static void evict(struct inode *inode) |
| 535 | { |
| 536 | const struct super_operations *op = inode->i_sb->s_op; |
| 537 | |
| 538 | BUG_ON(!(inode->i_state & I_FREEING)); |
| 539 | BUG_ON(!list_empty(&inode->i_lru)); |
| 540 | |
| 541 | if (!list_empty(&inode->i_wb_list)) |
| 542 | inode_wb_list_del(inode); |
| 543 | |
| 544 | inode_sb_list_del(inode); |
| 545 | |
| 546 | /* |
| 547 | * Wait for flusher thread to be done with the inode so that filesystem |
| 548 | * does not start destroying it while writeback is still running. Since |
| 549 | * the inode has I_FREEING set, flusher thread won't start new work on |
| 550 | * the inode. We just have to wait for running writeback to finish. |
| 551 | */ |
| 552 | inode_wait_for_writeback(inode); |
| 553 | |
| 554 | if (op->evict_inode) { |
| 555 | op->evict_inode(inode); |
| 556 | } else { |
| 557 | if (inode->i_data.nrpages) |
| 558 | truncate_inode_pages(&inode->i_data, 0); |
| 559 | clear_inode(inode); |
| 560 | } |
| 561 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
| 562 | bd_forget(inode); |
| 563 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
| 564 | cd_forget(inode); |
| 565 | |
| 566 | remove_inode_hash(inode); |
| 567 | |
| 568 | spin_lock(&inode->i_lock); |
| 569 | wake_up_bit(&inode->i_state, __I_NEW); |
| 570 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
| 571 | spin_unlock(&inode->i_lock); |
| 572 | |
| 573 | destroy_inode(inode); |
| 574 | } |
| 575 | |
| 576 | /* |
| 577 | * dispose_list - dispose of the contents of a local list |
| 578 | * @head: the head of the list to free |
| 579 | * |
| 580 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
| 581 | * need to worry about list corruption and SMP locks. |
| 582 | */ |
| 583 | static void dispose_list(struct list_head *head) |
| 584 | { |
| 585 | while (!list_empty(head)) { |
| 586 | struct inode *inode; |
| 587 | |
| 588 | inode = list_first_entry(head, struct inode, i_lru); |
| 589 | list_del_init(&inode->i_lru); |
| 590 | |
| 591 | evict(inode); |
| 592 | } |
| 593 | } |
| 594 | |
| 595 | /** |
| 596 | * evict_inodes - evict all evictable inodes for a superblock |
| 597 | * @sb: superblock to operate on |
| 598 | * |
| 599 | * Make sure that no inodes with zero refcount are retained. This is |
| 600 | * called by superblock shutdown after having MS_ACTIVE flag removed, |
| 601 | * so any inode reaching zero refcount during or after that call will |
| 602 | * be immediately evicted. |
| 603 | */ |
| 604 | void evict_inodes(struct super_block *sb) |
| 605 | { |
| 606 | struct inode *inode, *next; |
| 607 | LIST_HEAD(dispose); |
| 608 | |
| 609 | spin_lock(&inode_sb_list_lock); |
| 610 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
| 611 | if (atomic_read(&inode->i_count)) |
| 612 | continue; |
| 613 | |
| 614 | spin_lock(&inode->i_lock); |
| 615 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| 616 | spin_unlock(&inode->i_lock); |
| 617 | continue; |
| 618 | } |
| 619 | |
| 620 | inode->i_state |= I_FREEING; |
| 621 | inode_lru_list_del(inode); |
| 622 | spin_unlock(&inode->i_lock); |
| 623 | list_add(&inode->i_lru, &dispose); |
| 624 | } |
| 625 | spin_unlock(&inode_sb_list_lock); |
| 626 | |
| 627 | dispose_list(&dispose); |
| 628 | } |
| 629 | |
| 630 | /** |
| 631 | * invalidate_inodes - attempt to free all inodes on a superblock |
| 632 | * @sb: superblock to operate on |
| 633 | * @kill_dirty: flag to guide handling of dirty inodes |
| 634 | * |
| 635 | * Attempts to free all inodes for a given superblock. If there were any |
| 636 | * busy inodes return a non-zero value, else zero. |
| 637 | * If @kill_dirty is set, discard dirty inodes too, otherwise treat |
| 638 | * them as busy. |
| 639 | */ |
| 640 | int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
| 641 | { |
| 642 | int busy = 0; |
| 643 | struct inode *inode, *next; |
| 644 | LIST_HEAD(dispose); |
| 645 | |
| 646 | spin_lock(&inode_sb_list_lock); |
| 647 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
| 648 | spin_lock(&inode->i_lock); |
| 649 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| 650 | spin_unlock(&inode->i_lock); |
| 651 | continue; |
| 652 | } |
| 653 | if (inode->i_state & I_DIRTY && !kill_dirty) { |
| 654 | spin_unlock(&inode->i_lock); |
| 655 | busy = 1; |
| 656 | continue; |
| 657 | } |
| 658 | if (atomic_read(&inode->i_count)) { |
| 659 | spin_unlock(&inode->i_lock); |
| 660 | busy = 1; |
| 661 | continue; |
| 662 | } |
| 663 | |
| 664 | inode->i_state |= I_FREEING; |
| 665 | inode_lru_list_del(inode); |
| 666 | spin_unlock(&inode->i_lock); |
| 667 | list_add(&inode->i_lru, &dispose); |
| 668 | } |
| 669 | spin_unlock(&inode_sb_list_lock); |
| 670 | |
| 671 | dispose_list(&dispose); |
| 672 | |
| 673 | return busy; |
| 674 | } |
| 675 | |
| 676 | static int can_unuse(struct inode *inode) |
| 677 | { |
| 678 | if (inode->i_state & ~I_REFERENCED) |
| 679 | return 0; |
| 680 | if (inode_has_buffers(inode)) |
| 681 | return 0; |
| 682 | if (atomic_read(&inode->i_count)) |
| 683 | return 0; |
| 684 | if (inode->i_data.nrpages) |
| 685 | return 0; |
| 686 | return 1; |
| 687 | } |
| 688 | |
| 689 | /* |
| 690 | * Walk the superblock inode LRU for freeable inodes and attempt to free them. |
| 691 | * This is called from the superblock shrinker function with a number of inodes |
| 692 | * to trim from the LRU. Inodes to be freed are moved to a temporary list and |
| 693 | * then are freed outside inode_lock by dispose_list(). |
| 694 | * |
| 695 | * Any inodes which are pinned purely because of attached pagecache have their |
| 696 | * pagecache removed. If the inode has metadata buffers attached to |
| 697 | * mapping->private_list then try to remove them. |
| 698 | * |
| 699 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
| 700 | * used recently - the flag is set in iput_final(). When we encounter such an |
| 701 | * inode, clear the flag and move it to the back of the LRU so it gets another |
| 702 | * pass through the LRU before it gets reclaimed. This is necessary because of |
| 703 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
| 704 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
| 705 | * with this flag set because they are the inodes that are out of order. |
| 706 | */ |
| 707 | void prune_icache_sb(struct super_block *sb, int nr_to_scan) |
| 708 | { |
| 709 | LIST_HEAD(freeable); |
| 710 | int nr_scanned; |
| 711 | unsigned long reap = 0; |
| 712 | |
| 713 | spin_lock(&sb->s_inode_lru_lock); |
| 714 | for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) { |
| 715 | struct inode *inode; |
| 716 | |
| 717 | if (list_empty(&sb->s_inode_lru)) |
| 718 | break; |
| 719 | |
| 720 | inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru); |
| 721 | |
| 722 | /* |
| 723 | * we are inverting the sb->s_inode_lru_lock/inode->i_lock here, |
| 724 | * so use a trylock. If we fail to get the lock, just move the |
| 725 | * inode to the back of the list so we don't spin on it. |
| 726 | */ |
| 727 | if (!spin_trylock(&inode->i_lock)) { |
| 728 | list_move_tail(&inode->i_lru, &sb->s_inode_lru); |
| 729 | continue; |
| 730 | } |
| 731 | |
| 732 | /* |
| 733 | * Referenced or dirty inodes are still in use. Give them |
| 734 | * another pass through the LRU as we canot reclaim them now. |
| 735 | */ |
| 736 | if (atomic_read(&inode->i_count) || |
| 737 | (inode->i_state & ~I_REFERENCED)) { |
| 738 | list_del_init(&inode->i_lru); |
| 739 | spin_unlock(&inode->i_lock); |
| 740 | sb->s_nr_inodes_unused--; |
| 741 | this_cpu_dec(nr_unused); |
| 742 | continue; |
| 743 | } |
| 744 | |
| 745 | /* recently referenced inodes get one more pass */ |
| 746 | if (inode->i_state & I_REFERENCED) { |
| 747 | inode->i_state &= ~I_REFERENCED; |
| 748 | list_move(&inode->i_lru, &sb->s_inode_lru); |
| 749 | spin_unlock(&inode->i_lock); |
| 750 | continue; |
| 751 | } |
| 752 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
| 753 | __iget(inode); |
| 754 | spin_unlock(&inode->i_lock); |
| 755 | spin_unlock(&sb->s_inode_lru_lock); |
| 756 | if (remove_inode_buffers(inode)) |
| 757 | reap += invalidate_mapping_pages(&inode->i_data, |
| 758 | 0, -1); |
| 759 | iput(inode); |
| 760 | spin_lock(&sb->s_inode_lru_lock); |
| 761 | |
| 762 | if (inode != list_entry(sb->s_inode_lru.next, |
| 763 | struct inode, i_lru)) |
| 764 | continue; /* wrong inode or list_empty */ |
| 765 | /* avoid lock inversions with trylock */ |
| 766 | if (!spin_trylock(&inode->i_lock)) |
| 767 | continue; |
| 768 | if (!can_unuse(inode)) { |
| 769 | spin_unlock(&inode->i_lock); |
| 770 | continue; |
| 771 | } |
| 772 | } |
| 773 | WARN_ON(inode->i_state & I_NEW); |
| 774 | inode->i_state |= I_FREEING; |
| 775 | spin_unlock(&inode->i_lock); |
| 776 | |
| 777 | list_move(&inode->i_lru, &freeable); |
| 778 | sb->s_nr_inodes_unused--; |
| 779 | this_cpu_dec(nr_unused); |
| 780 | } |
| 781 | if (current_is_kswapd()) |
| 782 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
| 783 | else |
| 784 | __count_vm_events(PGINODESTEAL, reap); |
| 785 | spin_unlock(&sb->s_inode_lru_lock); |
| 786 | if (current->reclaim_state) |
| 787 | current->reclaim_state->reclaimed_slab += reap; |
| 788 | |
| 789 | dispose_list(&freeable); |
| 790 | } |
| 791 | |
| 792 | static void __wait_on_freeing_inode(struct inode *inode); |
| 793 | /* |
| 794 | * Called with the inode lock held. |
| 795 | */ |
| 796 | static struct inode *find_inode(struct super_block *sb, |
| 797 | struct hlist_head *head, |
| 798 | int (*test)(struct inode *, void *), |
| 799 | void *data) |
| 800 | { |
| 801 | struct hlist_node *node; |
| 802 | struct inode *inode = NULL; |
| 803 | |
| 804 | repeat: |
| 805 | hlist_for_each_entry(inode, node, head, i_hash) { |
| 806 | spin_lock(&inode->i_lock); |
| 807 | if (inode->i_sb != sb) { |
| 808 | spin_unlock(&inode->i_lock); |
| 809 | continue; |
| 810 | } |
| 811 | if (!test(inode, data)) { |
| 812 | spin_unlock(&inode->i_lock); |
| 813 | continue; |
| 814 | } |
| 815 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
| 816 | __wait_on_freeing_inode(inode); |
| 817 | goto repeat; |
| 818 | } |
| 819 | __iget(inode); |
| 820 | spin_unlock(&inode->i_lock); |
| 821 | return inode; |
| 822 | } |
| 823 | return NULL; |
| 824 | } |
| 825 | |
| 826 | /* |
| 827 | * find_inode_fast is the fast path version of find_inode, see the comment at |
| 828 | * iget_locked for details. |
| 829 | */ |
| 830 | static struct inode *find_inode_fast(struct super_block *sb, |
| 831 | struct hlist_head *head, unsigned long ino) |
| 832 | { |
| 833 | struct hlist_node *node; |
| 834 | struct inode *inode = NULL; |
| 835 | |
| 836 | repeat: |
| 837 | hlist_for_each_entry(inode, node, head, i_hash) { |
| 838 | spin_lock(&inode->i_lock); |
| 839 | if (inode->i_ino != ino) { |
| 840 | spin_unlock(&inode->i_lock); |
| 841 | continue; |
| 842 | } |
| 843 | if (inode->i_sb != sb) { |
| 844 | spin_unlock(&inode->i_lock); |
| 845 | continue; |
| 846 | } |
| 847 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
| 848 | __wait_on_freeing_inode(inode); |
| 849 | goto repeat; |
| 850 | } |
| 851 | __iget(inode); |
| 852 | spin_unlock(&inode->i_lock); |
| 853 | return inode; |
| 854 | } |
| 855 | return NULL; |
| 856 | } |
| 857 | |
| 858 | /* |
| 859 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
| 860 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
| 861 | * to renew the exhausted range. |
| 862 | * |
| 863 | * This does not significantly increase overflow rate because every CPU can |
| 864 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
| 865 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
| 866 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
| 867 | * overflow rate by 2x, which does not seem too significant. |
| 868 | * |
| 869 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
| 870 | * error if st_ino won't fit in target struct field. Use 32bit counter |
| 871 | * here to attempt to avoid that. |
| 872 | */ |
| 873 | #define LAST_INO_BATCH 1024 |
| 874 | static DEFINE_PER_CPU(unsigned int, last_ino); |
| 875 | |
| 876 | unsigned int get_next_ino(void) |
| 877 | { |
| 878 | unsigned int *p = &get_cpu_var(last_ino); |
| 879 | unsigned int res = *p; |
| 880 | |
| 881 | #ifdef CONFIG_SMP |
| 882 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
| 883 | static atomic_t shared_last_ino; |
| 884 | int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
| 885 | |
| 886 | res = next - LAST_INO_BATCH; |
| 887 | } |
| 888 | #endif |
| 889 | |
| 890 | *p = ++res; |
| 891 | put_cpu_var(last_ino); |
| 892 | return res; |
| 893 | } |
| 894 | EXPORT_SYMBOL(get_next_ino); |
| 895 | |
| 896 | /** |
| 897 | * new_inode_pseudo - obtain an inode |
| 898 | * @sb: superblock |
| 899 | * |
| 900 | * Allocates a new inode for given superblock. |
| 901 | * Inode wont be chained in superblock s_inodes list |
| 902 | * This means : |
| 903 | * - fs can't be unmount |
| 904 | * - quotas, fsnotify, writeback can't work |
| 905 | */ |
| 906 | struct inode *new_inode_pseudo(struct super_block *sb) |
| 907 | { |
| 908 | struct inode *inode = alloc_inode(sb); |
| 909 | |
| 910 | if (inode) { |
| 911 | spin_lock(&inode->i_lock); |
| 912 | inode->i_state = 0; |
| 913 | spin_unlock(&inode->i_lock); |
| 914 | INIT_LIST_HEAD(&inode->i_sb_list); |
| 915 | } |
| 916 | return inode; |
| 917 | } |
| 918 | |
| 919 | /** |
| 920 | * new_inode - obtain an inode |
| 921 | * @sb: superblock |
| 922 | * |
| 923 | * Allocates a new inode for given superblock. The default gfp_mask |
| 924 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
| 925 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
| 926 | * for the page cache are not reclaimable or migratable, |
| 927 | * mapping_set_gfp_mask() must be called with suitable flags on the |
| 928 | * newly created inode's mapping |
| 929 | * |
| 930 | */ |
| 931 | struct inode *new_inode(struct super_block *sb) |
| 932 | { |
| 933 | struct inode *inode; |
| 934 | |
| 935 | spin_lock_prefetch(&inode_sb_list_lock); |
| 936 | |
| 937 | inode = new_inode_pseudo(sb); |
| 938 | if (inode) |
| 939 | inode_sb_list_add(inode); |
| 940 | return inode; |
| 941 | } |
| 942 | EXPORT_SYMBOL(new_inode); |
| 943 | |
| 944 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 945 | void lockdep_annotate_inode_mutex_key(struct inode *inode) |
| 946 | { |
| 947 | if (S_ISDIR(inode->i_mode)) { |
| 948 | struct file_system_type *type = inode->i_sb->s_type; |
| 949 | |
| 950 | /* Set new key only if filesystem hasn't already changed it */ |
| 951 | if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) { |
| 952 | /* |
| 953 | * ensure nobody is actually holding i_mutex |
| 954 | */ |
| 955 | mutex_destroy(&inode->i_mutex); |
| 956 | mutex_init(&inode->i_mutex); |
| 957 | lockdep_set_class(&inode->i_mutex, |
| 958 | &type->i_mutex_dir_key); |
| 959 | } |
| 960 | } |
| 961 | } |
| 962 | EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key); |
| 963 | #endif |
| 964 | |
| 965 | /** |
| 966 | * unlock_new_inode - clear the I_NEW state and wake up any waiters |
| 967 | * @inode: new inode to unlock |
| 968 | * |
| 969 | * Called when the inode is fully initialised to clear the new state of the |
| 970 | * inode and wake up anyone waiting for the inode to finish initialisation. |
| 971 | */ |
| 972 | void unlock_new_inode(struct inode *inode) |
| 973 | { |
| 974 | lockdep_annotate_inode_mutex_key(inode); |
| 975 | spin_lock(&inode->i_lock); |
| 976 | WARN_ON(!(inode->i_state & I_NEW)); |
| 977 | inode->i_state &= ~I_NEW; |
| 978 | smp_mb(); |
| 979 | wake_up_bit(&inode->i_state, __I_NEW); |
| 980 | spin_unlock(&inode->i_lock); |
| 981 | } |
| 982 | EXPORT_SYMBOL(unlock_new_inode); |
| 983 | |
| 984 | /** |
| 985 | * iget5_locked - obtain an inode from a mounted file system |
| 986 | * @sb: super block of file system |
| 987 | * @hashval: hash value (usually inode number) to get |
| 988 | * @test: callback used for comparisons between inodes |
| 989 | * @set: callback used to initialize a new struct inode |
| 990 | * @data: opaque data pointer to pass to @test and @set |
| 991 | * |
| 992 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 993 | * and if present it is return it with an increased reference count. This is |
| 994 | * a generalized version of iget_locked() for file systems where the inode |
| 995 | * number is not sufficient for unique identification of an inode. |
| 996 | * |
| 997 | * If the inode is not in cache, allocate a new inode and return it locked, |
| 998 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
| 999 | * before unlocking it via unlock_new_inode(). |
| 1000 | * |
| 1001 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
| 1002 | * sleep. |
| 1003 | */ |
| 1004 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
| 1005 | int (*test)(struct inode *, void *), |
| 1006 | int (*set)(struct inode *, void *), void *data) |
| 1007 | { |
| 1008 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| 1009 | struct inode *inode; |
| 1010 | |
| 1011 | spin_lock(&inode_hash_lock); |
| 1012 | inode = find_inode(sb, head, test, data); |
| 1013 | spin_unlock(&inode_hash_lock); |
| 1014 | |
| 1015 | if (inode) { |
| 1016 | wait_on_inode(inode); |
| 1017 | return inode; |
| 1018 | } |
| 1019 | |
| 1020 | inode = alloc_inode(sb); |
| 1021 | if (inode) { |
| 1022 | struct inode *old; |
| 1023 | |
| 1024 | spin_lock(&inode_hash_lock); |
| 1025 | /* We released the lock, so.. */ |
| 1026 | old = find_inode(sb, head, test, data); |
| 1027 | if (!old) { |
| 1028 | if (set(inode, data)) |
| 1029 | goto set_failed; |
| 1030 | |
| 1031 | spin_lock(&inode->i_lock); |
| 1032 | inode->i_state = I_NEW; |
| 1033 | hlist_add_head(&inode->i_hash, head); |
| 1034 | spin_unlock(&inode->i_lock); |
| 1035 | inode_sb_list_add(inode); |
| 1036 | spin_unlock(&inode_hash_lock); |
| 1037 | |
| 1038 | /* Return the locked inode with I_NEW set, the |
| 1039 | * caller is responsible for filling in the contents |
| 1040 | */ |
| 1041 | return inode; |
| 1042 | } |
| 1043 | |
| 1044 | /* |
| 1045 | * Uhhuh, somebody else created the same inode under |
| 1046 | * us. Use the old inode instead of the one we just |
| 1047 | * allocated. |
| 1048 | */ |
| 1049 | spin_unlock(&inode_hash_lock); |
| 1050 | destroy_inode(inode); |
| 1051 | inode = old; |
| 1052 | wait_on_inode(inode); |
| 1053 | } |
| 1054 | return inode; |
| 1055 | |
| 1056 | set_failed: |
| 1057 | spin_unlock(&inode_hash_lock); |
| 1058 | destroy_inode(inode); |
| 1059 | return NULL; |
| 1060 | } |
| 1061 | EXPORT_SYMBOL(iget5_locked); |
| 1062 | |
| 1063 | /** |
| 1064 | * iget_locked - obtain an inode from a mounted file system |
| 1065 | * @sb: super block of file system |
| 1066 | * @ino: inode number to get |
| 1067 | * |
| 1068 | * Search for the inode specified by @ino in the inode cache and if present |
| 1069 | * return it with an increased reference count. This is for file systems |
| 1070 | * where the inode number is sufficient for unique identification of an inode. |
| 1071 | * |
| 1072 | * If the inode is not in cache, allocate a new inode and return it locked, |
| 1073 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
| 1074 | * before unlocking it via unlock_new_inode(). |
| 1075 | */ |
| 1076 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
| 1077 | { |
| 1078 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1079 | struct inode *inode; |
| 1080 | |
| 1081 | spin_lock(&inode_hash_lock); |
| 1082 | inode = find_inode_fast(sb, head, ino); |
| 1083 | spin_unlock(&inode_hash_lock); |
| 1084 | if (inode) { |
| 1085 | wait_on_inode(inode); |
| 1086 | return inode; |
| 1087 | } |
| 1088 | |
| 1089 | inode = alloc_inode(sb); |
| 1090 | if (inode) { |
| 1091 | struct inode *old; |
| 1092 | |
| 1093 | spin_lock(&inode_hash_lock); |
| 1094 | /* We released the lock, so.. */ |
| 1095 | old = find_inode_fast(sb, head, ino); |
| 1096 | if (!old) { |
| 1097 | inode->i_ino = ino; |
| 1098 | spin_lock(&inode->i_lock); |
| 1099 | inode->i_state = I_NEW; |
| 1100 | hlist_add_head(&inode->i_hash, head); |
| 1101 | spin_unlock(&inode->i_lock); |
| 1102 | inode_sb_list_add(inode); |
| 1103 | spin_unlock(&inode_hash_lock); |
| 1104 | |
| 1105 | /* Return the locked inode with I_NEW set, the |
| 1106 | * caller is responsible for filling in the contents |
| 1107 | */ |
| 1108 | return inode; |
| 1109 | } |
| 1110 | |
| 1111 | /* |
| 1112 | * Uhhuh, somebody else created the same inode under |
| 1113 | * us. Use the old inode instead of the one we just |
| 1114 | * allocated. |
| 1115 | */ |
| 1116 | spin_unlock(&inode_hash_lock); |
| 1117 | destroy_inode(inode); |
| 1118 | inode = old; |
| 1119 | wait_on_inode(inode); |
| 1120 | } |
| 1121 | return inode; |
| 1122 | } |
| 1123 | EXPORT_SYMBOL(iget_locked); |
| 1124 | |
| 1125 | /* |
| 1126 | * search the inode cache for a matching inode number. |
| 1127 | * If we find one, then the inode number we are trying to |
| 1128 | * allocate is not unique and so we should not use it. |
| 1129 | * |
| 1130 | * Returns 1 if the inode number is unique, 0 if it is not. |
| 1131 | */ |
| 1132 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
| 1133 | { |
| 1134 | struct hlist_head *b = inode_hashtable + hash(sb, ino); |
| 1135 | struct hlist_node *node; |
| 1136 | struct inode *inode; |
| 1137 | |
| 1138 | spin_lock(&inode_hash_lock); |
| 1139 | hlist_for_each_entry(inode, node, b, i_hash) { |
| 1140 | if (inode->i_ino == ino && inode->i_sb == sb) { |
| 1141 | spin_unlock(&inode_hash_lock); |
| 1142 | return 0; |
| 1143 | } |
| 1144 | } |
| 1145 | spin_unlock(&inode_hash_lock); |
| 1146 | |
| 1147 | return 1; |
| 1148 | } |
| 1149 | |
| 1150 | /** |
| 1151 | * iunique - get a unique inode number |
| 1152 | * @sb: superblock |
| 1153 | * @max_reserved: highest reserved inode number |
| 1154 | * |
| 1155 | * Obtain an inode number that is unique on the system for a given |
| 1156 | * superblock. This is used by file systems that have no natural |
| 1157 | * permanent inode numbering system. An inode number is returned that |
| 1158 | * is higher than the reserved limit but unique. |
| 1159 | * |
| 1160 | * BUGS: |
| 1161 | * With a large number of inodes live on the file system this function |
| 1162 | * currently becomes quite slow. |
| 1163 | */ |
| 1164 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
| 1165 | { |
| 1166 | /* |
| 1167 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
| 1168 | * error if st_ino won't fit in target struct field. Use 32bit counter |
| 1169 | * here to attempt to avoid that. |
| 1170 | */ |
| 1171 | static DEFINE_SPINLOCK(iunique_lock); |
| 1172 | static unsigned int counter; |
| 1173 | ino_t res; |
| 1174 | |
| 1175 | spin_lock(&iunique_lock); |
| 1176 | do { |
| 1177 | if (counter <= max_reserved) |
| 1178 | counter = max_reserved + 1; |
| 1179 | res = counter++; |
| 1180 | } while (!test_inode_iunique(sb, res)); |
| 1181 | spin_unlock(&iunique_lock); |
| 1182 | |
| 1183 | return res; |
| 1184 | } |
| 1185 | EXPORT_SYMBOL(iunique); |
| 1186 | |
| 1187 | struct inode *igrab(struct inode *inode) |
| 1188 | { |
| 1189 | spin_lock(&inode->i_lock); |
| 1190 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
| 1191 | __iget(inode); |
| 1192 | spin_unlock(&inode->i_lock); |
| 1193 | } else { |
| 1194 | spin_unlock(&inode->i_lock); |
| 1195 | /* |
| 1196 | * Handle the case where s_op->clear_inode is not been |
| 1197 | * called yet, and somebody is calling igrab |
| 1198 | * while the inode is getting freed. |
| 1199 | */ |
| 1200 | inode = NULL; |
| 1201 | } |
| 1202 | return inode; |
| 1203 | } |
| 1204 | EXPORT_SYMBOL(igrab); |
| 1205 | |
| 1206 | /** |
| 1207 | * ilookup5_nowait - search for an inode in the inode cache |
| 1208 | * @sb: super block of file system to search |
| 1209 | * @hashval: hash value (usually inode number) to search for |
| 1210 | * @test: callback used for comparisons between inodes |
| 1211 | * @data: opaque data pointer to pass to @test |
| 1212 | * |
| 1213 | * Search for the inode specified by @hashval and @data in the inode cache. |
| 1214 | * If the inode is in the cache, the inode is returned with an incremented |
| 1215 | * reference count. |
| 1216 | * |
| 1217 | * Note: I_NEW is not waited upon so you have to be very careful what you do |
| 1218 | * with the returned inode. You probably should be using ilookup5() instead. |
| 1219 | * |
| 1220 | * Note2: @test is called with the inode_hash_lock held, so can't sleep. |
| 1221 | */ |
| 1222 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
| 1223 | int (*test)(struct inode *, void *), void *data) |
| 1224 | { |
| 1225 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| 1226 | struct inode *inode; |
| 1227 | |
| 1228 | spin_lock(&inode_hash_lock); |
| 1229 | inode = find_inode(sb, head, test, data); |
| 1230 | spin_unlock(&inode_hash_lock); |
| 1231 | |
| 1232 | return inode; |
| 1233 | } |
| 1234 | EXPORT_SYMBOL(ilookup5_nowait); |
| 1235 | |
| 1236 | /** |
| 1237 | * ilookup5 - search for an inode in the inode cache |
| 1238 | * @sb: super block of file system to search |
| 1239 | * @hashval: hash value (usually inode number) to search for |
| 1240 | * @test: callback used for comparisons between inodes |
| 1241 | * @data: opaque data pointer to pass to @test |
| 1242 | * |
| 1243 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 1244 | * and if the inode is in the cache, return the inode with an incremented |
| 1245 | * reference count. Waits on I_NEW before returning the inode. |
| 1246 | * returned with an incremented reference count. |
| 1247 | * |
| 1248 | * This is a generalized version of ilookup() for file systems where the |
| 1249 | * inode number is not sufficient for unique identification of an inode. |
| 1250 | * |
| 1251 | * Note: @test is called with the inode_hash_lock held, so can't sleep. |
| 1252 | */ |
| 1253 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
| 1254 | int (*test)(struct inode *, void *), void *data) |
| 1255 | { |
| 1256 | struct inode *inode = ilookup5_nowait(sb, hashval, test, data); |
| 1257 | |
| 1258 | if (inode) |
| 1259 | wait_on_inode(inode); |
| 1260 | return inode; |
| 1261 | } |
| 1262 | EXPORT_SYMBOL(ilookup5); |
| 1263 | |
| 1264 | /** |
| 1265 | * ilookup - search for an inode in the inode cache |
| 1266 | * @sb: super block of file system to search |
| 1267 | * @ino: inode number to search for |
| 1268 | * |
| 1269 | * Search for the inode @ino in the inode cache, and if the inode is in the |
| 1270 | * cache, the inode is returned with an incremented reference count. |
| 1271 | */ |
| 1272 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
| 1273 | { |
| 1274 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1275 | struct inode *inode; |
| 1276 | |
| 1277 | spin_lock(&inode_hash_lock); |
| 1278 | inode = find_inode_fast(sb, head, ino); |
| 1279 | spin_unlock(&inode_hash_lock); |
| 1280 | |
| 1281 | if (inode) |
| 1282 | wait_on_inode(inode); |
| 1283 | return inode; |
| 1284 | } |
| 1285 | EXPORT_SYMBOL(ilookup); |
| 1286 | |
| 1287 | int insert_inode_locked(struct inode *inode) |
| 1288 | { |
| 1289 | struct super_block *sb = inode->i_sb; |
| 1290 | ino_t ino = inode->i_ino; |
| 1291 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1292 | |
| 1293 | while (1) { |
| 1294 | struct hlist_node *node; |
| 1295 | struct inode *old = NULL; |
| 1296 | spin_lock(&inode_hash_lock); |
| 1297 | hlist_for_each_entry(old, node, head, i_hash) { |
| 1298 | if (old->i_ino != ino) |
| 1299 | continue; |
| 1300 | if (old->i_sb != sb) |
| 1301 | continue; |
| 1302 | spin_lock(&old->i_lock); |
| 1303 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
| 1304 | spin_unlock(&old->i_lock); |
| 1305 | continue; |
| 1306 | } |
| 1307 | break; |
| 1308 | } |
| 1309 | if (likely(!node)) { |
| 1310 | spin_lock(&inode->i_lock); |
| 1311 | inode->i_state |= I_NEW; |
| 1312 | hlist_add_head(&inode->i_hash, head); |
| 1313 | spin_unlock(&inode->i_lock); |
| 1314 | spin_unlock(&inode_hash_lock); |
| 1315 | return 0; |
| 1316 | } |
| 1317 | __iget(old); |
| 1318 | spin_unlock(&old->i_lock); |
| 1319 | spin_unlock(&inode_hash_lock); |
| 1320 | wait_on_inode(old); |
| 1321 | if (unlikely(!inode_unhashed(old))) { |
| 1322 | iput(old); |
| 1323 | return -EBUSY; |
| 1324 | } |
| 1325 | iput(old); |
| 1326 | } |
| 1327 | } |
| 1328 | EXPORT_SYMBOL(insert_inode_locked); |
| 1329 | |
| 1330 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
| 1331 | int (*test)(struct inode *, void *), void *data) |
| 1332 | { |
| 1333 | struct super_block *sb = inode->i_sb; |
| 1334 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| 1335 | |
| 1336 | while (1) { |
| 1337 | struct hlist_node *node; |
| 1338 | struct inode *old = NULL; |
| 1339 | |
| 1340 | spin_lock(&inode_hash_lock); |
| 1341 | hlist_for_each_entry(old, node, head, i_hash) { |
| 1342 | if (old->i_sb != sb) |
| 1343 | continue; |
| 1344 | if (!test(old, data)) |
| 1345 | continue; |
| 1346 | spin_lock(&old->i_lock); |
| 1347 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
| 1348 | spin_unlock(&old->i_lock); |
| 1349 | continue; |
| 1350 | } |
| 1351 | break; |
| 1352 | } |
| 1353 | if (likely(!node)) { |
| 1354 | spin_lock(&inode->i_lock); |
| 1355 | inode->i_state |= I_NEW; |
| 1356 | hlist_add_head(&inode->i_hash, head); |
| 1357 | spin_unlock(&inode->i_lock); |
| 1358 | spin_unlock(&inode_hash_lock); |
| 1359 | return 0; |
| 1360 | } |
| 1361 | __iget(old); |
| 1362 | spin_unlock(&old->i_lock); |
| 1363 | spin_unlock(&inode_hash_lock); |
| 1364 | wait_on_inode(old); |
| 1365 | if (unlikely(!inode_unhashed(old))) { |
| 1366 | iput(old); |
| 1367 | return -EBUSY; |
| 1368 | } |
| 1369 | iput(old); |
| 1370 | } |
| 1371 | } |
| 1372 | EXPORT_SYMBOL(insert_inode_locked4); |
| 1373 | |
| 1374 | |
| 1375 | int generic_delete_inode(struct inode *inode) |
| 1376 | { |
| 1377 | return 1; |
| 1378 | } |
| 1379 | EXPORT_SYMBOL(generic_delete_inode); |
| 1380 | |
| 1381 | /* |
| 1382 | * Called when we're dropping the last reference |
| 1383 | * to an inode. |
| 1384 | * |
| 1385 | * Call the FS "drop_inode()" function, defaulting to |
| 1386 | * the legacy UNIX filesystem behaviour. If it tells |
| 1387 | * us to evict inode, do so. Otherwise, retain inode |
| 1388 | * in cache if fs is alive, sync and evict if fs is |
| 1389 | * shutting down. |
| 1390 | */ |
| 1391 | static void iput_final(struct inode *inode) |
| 1392 | { |
| 1393 | struct super_block *sb = inode->i_sb; |
| 1394 | const struct super_operations *op = inode->i_sb->s_op; |
| 1395 | int drop; |
| 1396 | |
| 1397 | WARN_ON(inode->i_state & I_NEW); |
| 1398 | |
| 1399 | if (op->drop_inode) |
| 1400 | drop = op->drop_inode(inode); |
| 1401 | else |
| 1402 | drop = generic_drop_inode(inode); |
| 1403 | |
| 1404 | if (!drop && (sb->s_flags & MS_ACTIVE)) { |
| 1405 | inode->i_state |= I_REFERENCED; |
| 1406 | inode_add_lru(inode); |
| 1407 | spin_unlock(&inode->i_lock); |
| 1408 | return; |
| 1409 | } |
| 1410 | |
| 1411 | if (!drop) { |
| 1412 | inode->i_state |= I_WILL_FREE; |
| 1413 | spin_unlock(&inode->i_lock); |
| 1414 | write_inode_now(inode, 1); |
| 1415 | spin_lock(&inode->i_lock); |
| 1416 | WARN_ON(inode->i_state & I_NEW); |
| 1417 | inode->i_state &= ~I_WILL_FREE; |
| 1418 | } |
| 1419 | |
| 1420 | inode->i_state |= I_FREEING; |
| 1421 | if (!list_empty(&inode->i_lru)) |
| 1422 | inode_lru_list_del(inode); |
| 1423 | spin_unlock(&inode->i_lock); |
| 1424 | |
| 1425 | evict(inode); |
| 1426 | } |
| 1427 | |
| 1428 | /** |
| 1429 | * iput - put an inode |
| 1430 | * @inode: inode to put |
| 1431 | * |
| 1432 | * Puts an inode, dropping its usage count. If the inode use count hits |
| 1433 | * zero, the inode is then freed and may also be destroyed. |
| 1434 | * |
| 1435 | * Consequently, iput() can sleep. |
| 1436 | */ |
| 1437 | void iput(struct inode *inode) |
| 1438 | { |
| 1439 | if (inode) { |
| 1440 | BUG_ON(inode->i_state & I_CLEAR); |
| 1441 | |
| 1442 | if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) |
| 1443 | iput_final(inode); |
| 1444 | } |
| 1445 | } |
| 1446 | EXPORT_SYMBOL(iput); |
| 1447 | |
| 1448 | /** |
| 1449 | * bmap - find a block number in a file |
| 1450 | * @inode: inode of file |
| 1451 | * @block: block to find |
| 1452 | * |
| 1453 | * Returns the block number on the device holding the inode that |
| 1454 | * is the disk block number for the block of the file requested. |
| 1455 | * That is, asked for block 4 of inode 1 the function will return the |
| 1456 | * disk block relative to the disk start that holds that block of the |
| 1457 | * file. |
| 1458 | */ |
| 1459 | sector_t bmap(struct inode *inode, sector_t block) |
| 1460 | { |
| 1461 | sector_t res = 0; |
| 1462 | if (inode->i_mapping->a_ops->bmap) |
| 1463 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
| 1464 | return res; |
| 1465 | } |
| 1466 | EXPORT_SYMBOL(bmap); |
| 1467 | |
| 1468 | /* |
| 1469 | * With relative atime, only update atime if the previous atime is |
| 1470 | * earlier than either the ctime or mtime or if at least a day has |
| 1471 | * passed since the last atime update. |
| 1472 | */ |
| 1473 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
| 1474 | struct timespec now) |
| 1475 | { |
| 1476 | |
| 1477 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
| 1478 | return 1; |
| 1479 | /* |
| 1480 | * Is mtime younger than atime? If yes, update atime: |
| 1481 | */ |
| 1482 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
| 1483 | return 1; |
| 1484 | /* |
| 1485 | * Is ctime younger than atime? If yes, update atime: |
| 1486 | */ |
| 1487 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
| 1488 | return 1; |
| 1489 | |
| 1490 | /* |
| 1491 | * Is the previous atime value older than a day? If yes, |
| 1492 | * update atime: |
| 1493 | */ |
| 1494 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
| 1495 | return 1; |
| 1496 | /* |
| 1497 | * Good, we can skip the atime update: |
| 1498 | */ |
| 1499 | return 0; |
| 1500 | } |
| 1501 | |
| 1502 | /* |
| 1503 | * This does the actual work of updating an inodes time or version. Must have |
| 1504 | * had called mnt_want_write() before calling this. |
| 1505 | */ |
| 1506 | static int update_time(struct inode *inode, struct timespec *time, int flags) |
| 1507 | { |
| 1508 | if (inode->i_op->update_time) |
| 1509 | return inode->i_op->update_time(inode, time, flags); |
| 1510 | |
| 1511 | if (flags & S_ATIME) |
| 1512 | inode->i_atime = *time; |
| 1513 | if (flags & S_VERSION) |
| 1514 | inode_inc_iversion(inode); |
| 1515 | if (flags & S_CTIME) |
| 1516 | inode->i_ctime = *time; |
| 1517 | if (flags & S_MTIME) |
| 1518 | inode->i_mtime = *time; |
| 1519 | mark_inode_dirty_sync(inode); |
| 1520 | return 0; |
| 1521 | } |
| 1522 | |
| 1523 | /** |
| 1524 | * touch_atime - update the access time |
| 1525 | * @path: the &struct path to update |
| 1526 | * |
| 1527 | * Update the accessed time on an inode and mark it for writeback. |
| 1528 | * This function automatically handles read only file systems and media, |
| 1529 | * as well as the "noatime" flag and inode specific "noatime" markers. |
| 1530 | */ |
| 1531 | void touch_atime(struct path *path) |
| 1532 | { |
| 1533 | struct vfsmount *mnt = path->mnt; |
| 1534 | struct inode *inode = path->dentry->d_inode; |
| 1535 | struct timespec now; |
| 1536 | |
| 1537 | if (inode->i_flags & S_NOATIME) |
| 1538 | return; |
| 1539 | if (IS_NOATIME(inode)) |
| 1540 | return; |
| 1541 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
| 1542 | return; |
| 1543 | |
| 1544 | if (mnt->mnt_flags & MNT_NOATIME) |
| 1545 | return; |
| 1546 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
| 1547 | return; |
| 1548 | |
| 1549 | now = current_fs_time(inode->i_sb); |
| 1550 | |
| 1551 | if (!relatime_need_update(mnt, inode, now)) |
| 1552 | return; |
| 1553 | |
| 1554 | if (timespec_equal(&inode->i_atime, &now)) |
| 1555 | return; |
| 1556 | |
| 1557 | if (!sb_start_write_trylock(inode->i_sb)) |
| 1558 | return; |
| 1559 | |
| 1560 | if (__mnt_want_write(mnt)) |
| 1561 | goto skip_update; |
| 1562 | /* |
| 1563 | * File systems can error out when updating inodes if they need to |
| 1564 | * allocate new space to modify an inode (such is the case for |
| 1565 | * Btrfs), but since we touch atime while walking down the path we |
| 1566 | * really don't care if we failed to update the atime of the file, |
| 1567 | * so just ignore the return value. |
| 1568 | * We may also fail on filesystems that have the ability to make parts |
| 1569 | * of the fs read only, e.g. subvolumes in Btrfs. |
| 1570 | */ |
| 1571 | update_time(inode, &now, S_ATIME); |
| 1572 | __mnt_drop_write(mnt); |
| 1573 | skip_update: |
| 1574 | sb_end_write(inode->i_sb); |
| 1575 | } |
| 1576 | EXPORT_SYMBOL(touch_atime); |
| 1577 | |
| 1578 | /* |
| 1579 | * The logic we want is |
| 1580 | * |
| 1581 | * if suid or (sgid and xgrp) |
| 1582 | * remove privs |
| 1583 | */ |
| 1584 | int should_remove_suid(struct dentry *dentry) |
| 1585 | { |
| 1586 | umode_t mode = dentry->d_inode->i_mode; |
| 1587 | int kill = 0; |
| 1588 | |
| 1589 | /* suid always must be killed */ |
| 1590 | if (unlikely(mode & S_ISUID)) |
| 1591 | kill = ATTR_KILL_SUID; |
| 1592 | |
| 1593 | /* |
| 1594 | * sgid without any exec bits is just a mandatory locking mark; leave |
| 1595 | * it alone. If some exec bits are set, it's a real sgid; kill it. |
| 1596 | */ |
| 1597 | if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) |
| 1598 | kill |= ATTR_KILL_SGID; |
| 1599 | |
| 1600 | if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) |
| 1601 | return kill; |
| 1602 | |
| 1603 | return 0; |
| 1604 | } |
| 1605 | EXPORT_SYMBOL(should_remove_suid); |
| 1606 | |
| 1607 | static int __remove_suid(struct dentry *dentry, int kill) |
| 1608 | { |
| 1609 | struct iattr newattrs; |
| 1610 | |
| 1611 | newattrs.ia_valid = ATTR_FORCE | kill; |
| 1612 | return notify_change(dentry, &newattrs); |
| 1613 | } |
| 1614 | |
| 1615 | int file_remove_suid(struct file *file) |
| 1616 | { |
| 1617 | struct dentry *dentry = file->f_path.dentry; |
| 1618 | struct inode *inode = dentry->d_inode; |
| 1619 | int killsuid; |
| 1620 | int killpriv; |
| 1621 | int error = 0; |
| 1622 | |
| 1623 | /* Fast path for nothing security related */ |
| 1624 | if (IS_NOSEC(inode)) |
| 1625 | return 0; |
| 1626 | |
| 1627 | killsuid = should_remove_suid(dentry); |
| 1628 | killpriv = security_inode_need_killpriv(dentry); |
| 1629 | |
| 1630 | if (killpriv < 0) |
| 1631 | return killpriv; |
| 1632 | if (killpriv) |
| 1633 | error = security_inode_killpriv(dentry); |
| 1634 | if (!error && killsuid) |
| 1635 | error = __remove_suid(dentry, killsuid); |
| 1636 | if (!error && (inode->i_sb->s_flags & MS_NOSEC)) |
| 1637 | inode->i_flags |= S_NOSEC; |
| 1638 | |
| 1639 | return error; |
| 1640 | } |
| 1641 | EXPORT_SYMBOL(file_remove_suid); |
| 1642 | |
| 1643 | /** |
| 1644 | * file_update_time - update mtime and ctime time |
| 1645 | * @file: file accessed |
| 1646 | * |
| 1647 | * Update the mtime and ctime members of an inode and mark the inode |
| 1648 | * for writeback. Note that this function is meant exclusively for |
| 1649 | * usage in the file write path of filesystems, and filesystems may |
| 1650 | * choose to explicitly ignore update via this function with the |
| 1651 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
| 1652 | * timestamps are handled by the server. This can return an error for |
| 1653 | * file systems who need to allocate space in order to update an inode. |
| 1654 | */ |
| 1655 | |
| 1656 | int file_update_time(struct file *file) |
| 1657 | { |
| 1658 | struct inode *inode = file->f_path.dentry->d_inode; |
| 1659 | struct timespec now; |
| 1660 | int sync_it = 0; |
| 1661 | int ret; |
| 1662 | |
| 1663 | /* First try to exhaust all avenues to not sync */ |
| 1664 | if (IS_NOCMTIME(inode)) |
| 1665 | return 0; |
| 1666 | |
| 1667 | now = current_fs_time(inode->i_sb); |
| 1668 | if (!timespec_equal(&inode->i_mtime, &now)) |
| 1669 | sync_it = S_MTIME; |
| 1670 | |
| 1671 | if (!timespec_equal(&inode->i_ctime, &now)) |
| 1672 | sync_it |= S_CTIME; |
| 1673 | |
| 1674 | if (IS_I_VERSION(inode)) |
| 1675 | sync_it |= S_VERSION; |
| 1676 | |
| 1677 | if (!sync_it) |
| 1678 | return 0; |
| 1679 | |
| 1680 | /* Finally allowed to write? Takes lock. */ |
| 1681 | if (__mnt_want_write_file(file)) |
| 1682 | return 0; |
| 1683 | |
| 1684 | ret = update_time(inode, &now, sync_it); |
| 1685 | __mnt_drop_write_file(file); |
| 1686 | |
| 1687 | return ret; |
| 1688 | } |
| 1689 | EXPORT_SYMBOL(file_update_time); |
| 1690 | |
| 1691 | int inode_needs_sync(struct inode *inode) |
| 1692 | { |
| 1693 | if (IS_SYNC(inode)) |
| 1694 | return 1; |
| 1695 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
| 1696 | return 1; |
| 1697 | return 0; |
| 1698 | } |
| 1699 | EXPORT_SYMBOL(inode_needs_sync); |
| 1700 | |
| 1701 | int inode_wait(void *word) |
| 1702 | { |
| 1703 | schedule(); |
| 1704 | return 0; |
| 1705 | } |
| 1706 | EXPORT_SYMBOL(inode_wait); |
| 1707 | |
| 1708 | /* |
| 1709 | * If we try to find an inode in the inode hash while it is being |
| 1710 | * deleted, we have to wait until the filesystem completes its |
| 1711 | * deletion before reporting that it isn't found. This function waits |
| 1712 | * until the deletion _might_ have completed. Callers are responsible |
| 1713 | * to recheck inode state. |
| 1714 | * |
| 1715 | * It doesn't matter if I_NEW is not set initially, a call to |
| 1716 | * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
| 1717 | * will DTRT. |
| 1718 | */ |
| 1719 | static void __wait_on_freeing_inode(struct inode *inode) |
| 1720 | { |
| 1721 | wait_queue_head_t *wq; |
| 1722 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
| 1723 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
| 1724 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
| 1725 | spin_unlock(&inode->i_lock); |
| 1726 | spin_unlock(&inode_hash_lock); |
| 1727 | schedule(); |
| 1728 | finish_wait(wq, &wait.wait); |
| 1729 | spin_lock(&inode_hash_lock); |
| 1730 | } |
| 1731 | |
| 1732 | static __initdata unsigned long ihash_entries; |
| 1733 | static int __init set_ihash_entries(char *str) |
| 1734 | { |
| 1735 | if (!str) |
| 1736 | return 0; |
| 1737 | ihash_entries = simple_strtoul(str, &str, 0); |
| 1738 | return 1; |
| 1739 | } |
| 1740 | __setup("ihash_entries=", set_ihash_entries); |
| 1741 | |
| 1742 | /* |
| 1743 | * Initialize the waitqueues and inode hash table. |
| 1744 | */ |
| 1745 | void __init inode_init_early(void) |
| 1746 | { |
| 1747 | unsigned int loop; |
| 1748 | |
| 1749 | /* If hashes are distributed across NUMA nodes, defer |
| 1750 | * hash allocation until vmalloc space is available. |
| 1751 | */ |
| 1752 | if (hashdist) |
| 1753 | return; |
| 1754 | |
| 1755 | inode_hashtable = |
| 1756 | alloc_large_system_hash("Inode-cache", |
| 1757 | sizeof(struct hlist_head), |
| 1758 | ihash_entries, |
| 1759 | 14, |
| 1760 | HASH_EARLY, |
| 1761 | &i_hash_shift, |
| 1762 | &i_hash_mask, |
| 1763 | 0, |
| 1764 | 0); |
| 1765 | |
| 1766 | for (loop = 0; loop < (1U << i_hash_shift); loop++) |
| 1767 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
| 1768 | } |
| 1769 | |
| 1770 | void __init inode_init(void) |
| 1771 | { |
| 1772 | unsigned int loop; |
| 1773 | |
| 1774 | /* inode slab cache */ |
| 1775 | inode_cachep = kmem_cache_create("inode_cache", |
| 1776 | sizeof(struct inode), |
| 1777 | 0, |
| 1778 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
| 1779 | SLAB_MEM_SPREAD), |
| 1780 | init_once); |
| 1781 | |
| 1782 | /* Hash may have been set up in inode_init_early */ |
| 1783 | if (!hashdist) |
| 1784 | return; |
| 1785 | |
| 1786 | inode_hashtable = |
| 1787 | alloc_large_system_hash("Inode-cache", |
| 1788 | sizeof(struct hlist_head), |
| 1789 | ihash_entries, |
| 1790 | 14, |
| 1791 | 0, |
| 1792 | &i_hash_shift, |
| 1793 | &i_hash_mask, |
| 1794 | 0, |
| 1795 | 0); |
| 1796 | |
| 1797 | for (loop = 0; loop < (1U << i_hash_shift); loop++) |
| 1798 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
| 1799 | } |
| 1800 | |
| 1801 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
| 1802 | { |
| 1803 | inode->i_mode = mode; |
| 1804 | if (S_ISCHR(mode)) { |
| 1805 | inode->i_fop = &def_chr_fops; |
| 1806 | inode->i_rdev = rdev; |
| 1807 | } else if (S_ISBLK(mode)) { |
| 1808 | inode->i_fop = &def_blk_fops; |
| 1809 | inode->i_rdev = rdev; |
| 1810 | } else if (S_ISFIFO(mode)) |
| 1811 | inode->i_fop = &def_fifo_fops; |
| 1812 | else if (S_ISSOCK(mode)) |
| 1813 | inode->i_fop = &bad_sock_fops; |
| 1814 | else |
| 1815 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
| 1816 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
| 1817 | inode->i_ino); |
| 1818 | } |
| 1819 | EXPORT_SYMBOL(init_special_inode); |
| 1820 | |
| 1821 | /** |
| 1822 | * inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
| 1823 | * @inode: New inode |
| 1824 | * @dir: Directory inode |
| 1825 | * @mode: mode of the new inode |
| 1826 | */ |
| 1827 | void inode_init_owner(struct inode *inode, const struct inode *dir, |
| 1828 | umode_t mode) |
| 1829 | { |
| 1830 | inode->i_uid = current_fsuid(); |
| 1831 | if (dir && dir->i_mode & S_ISGID) { |
| 1832 | inode->i_gid = dir->i_gid; |
| 1833 | if (S_ISDIR(mode)) |
| 1834 | mode |= S_ISGID; |
| 1835 | } else |
| 1836 | inode->i_gid = current_fsgid(); |
| 1837 | inode->i_mode = mode; |
| 1838 | } |
| 1839 | EXPORT_SYMBOL(inode_init_owner); |
| 1840 | |
| 1841 | /** |
| 1842 | * inode_owner_or_capable - check current task permissions to inode |
| 1843 | * @inode: inode being checked |
| 1844 | * |
| 1845 | * Return true if current either has CAP_FOWNER to the inode, or |
| 1846 | * owns the file. |
| 1847 | */ |
| 1848 | bool inode_owner_or_capable(const struct inode *inode) |
| 1849 | { |
| 1850 | if (uid_eq(current_fsuid(), inode->i_uid)) |
| 1851 | return true; |
| 1852 | if (inode_capable(inode, CAP_FOWNER)) |
| 1853 | return true; |
| 1854 | return false; |
| 1855 | } |
| 1856 | EXPORT_SYMBOL(inode_owner_or_capable); |
| 1857 | |
| 1858 | /* |
| 1859 | * Direct i/o helper functions |
| 1860 | */ |
| 1861 | static void __inode_dio_wait(struct inode *inode) |
| 1862 | { |
| 1863 | wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP); |
| 1864 | DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); |
| 1865 | |
| 1866 | do { |
| 1867 | prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE); |
| 1868 | if (atomic_read(&inode->i_dio_count)) |
| 1869 | schedule(); |
| 1870 | } while (atomic_read(&inode->i_dio_count)); |
| 1871 | finish_wait(wq, &q.wait); |
| 1872 | } |
| 1873 | |
| 1874 | /** |
| 1875 | * inode_dio_wait - wait for outstanding DIO requests to finish |
| 1876 | * @inode: inode to wait for |
| 1877 | * |
| 1878 | * Waits for all pending direct I/O requests to finish so that we can |
| 1879 | * proceed with a truncate or equivalent operation. |
| 1880 | * |
| 1881 | * Must be called under a lock that serializes taking new references |
| 1882 | * to i_dio_count, usually by inode->i_mutex. |
| 1883 | */ |
| 1884 | void inode_dio_wait(struct inode *inode) |
| 1885 | { |
| 1886 | if (atomic_read(&inode->i_dio_count)) |
| 1887 | __inode_dio_wait(inode); |
| 1888 | } |
| 1889 | EXPORT_SYMBOL(inode_dio_wait); |
| 1890 | |
| 1891 | /* |
| 1892 | * inode_dio_done - signal finish of a direct I/O requests |
| 1893 | * @inode: inode the direct I/O happens on |
| 1894 | * |
| 1895 | * This is called once we've finished processing a direct I/O request, |
| 1896 | * and is used to wake up callers waiting for direct I/O to be quiesced. |
| 1897 | */ |
| 1898 | void inode_dio_done(struct inode *inode) |
| 1899 | { |
| 1900 | if (atomic_dec_and_test(&inode->i_dio_count)) |
| 1901 | wake_up_bit(&inode->i_state, __I_DIO_WAKEUP); |
| 1902 | } |
| 1903 | EXPORT_SYMBOL(inode_dio_done); |