| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * (C) 1997 Linus Torvalds |
| 4 | * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation) |
| 5 | */ |
| 6 | #include <linux/export.h> |
| 7 | #include <linux/fs.h> |
| 8 | #include <linux/filelock.h> |
| 9 | #include <linux/mm.h> |
| 10 | #include <linux/backing-dev.h> |
| 11 | #include <linux/hash.h> |
| 12 | #include <linux/swap.h> |
| 13 | #include <linux/security.h> |
| 14 | #include <linux/cdev.h> |
| 15 | #include <linux/memblock.h> |
| 16 | #include <linux/fsnotify.h> |
| 17 | #include <linux/mount.h> |
| 18 | #include <linux/posix_acl.h> |
| 19 | #include <linux/buffer_head.h> /* for inode_has_buffers */ |
| 20 | #include <linux/ratelimit.h> |
| 21 | #include <linux/list_lru.h> |
| 22 | #include <linux/iversion.h> |
| 23 | #include <trace/events/writeback.h> |
| 24 | #include "internal.h" |
| 25 | |
| 26 | /* |
| 27 | * Inode locking rules: |
| 28 | * |
| 29 | * inode->i_lock protects: |
| 30 | * inode->i_state, inode->i_hash, __iget(), inode->i_io_list |
| 31 | * Inode LRU list locks protect: |
| 32 | * inode->i_sb->s_inode_lru, inode->i_lru |
| 33 | * inode->i_sb->s_inode_list_lock protects: |
| 34 | * inode->i_sb->s_inodes, inode->i_sb_list |
| 35 | * bdi->wb.list_lock protects: |
| 36 | * bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list |
| 37 | * inode_hash_lock protects: |
| 38 | * inode_hashtable, inode->i_hash |
| 39 | * |
| 40 | * Lock ordering: |
| 41 | * |
| 42 | * inode->i_sb->s_inode_list_lock |
| 43 | * inode->i_lock |
| 44 | * Inode LRU list locks |
| 45 | * |
| 46 | * bdi->wb.list_lock |
| 47 | * inode->i_lock |
| 48 | * |
| 49 | * inode_hash_lock |
| 50 | * inode->i_sb->s_inode_list_lock |
| 51 | * inode->i_lock |
| 52 | * |
| 53 | * iunique_lock |
| 54 | * inode_hash_lock |
| 55 | */ |
| 56 | |
| 57 | static unsigned int i_hash_mask __ro_after_init; |
| 58 | static unsigned int i_hash_shift __ro_after_init; |
| 59 | static struct hlist_head *inode_hashtable __ro_after_init; |
| 60 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
| 61 | |
| 62 | /* |
| 63 | * Empty aops. Can be used for the cases where the user does not |
| 64 | * define any of the address_space operations. |
| 65 | */ |
| 66 | const struct address_space_operations empty_aops = { |
| 67 | }; |
| 68 | EXPORT_SYMBOL(empty_aops); |
| 69 | |
| 70 | static DEFINE_PER_CPU(unsigned long, nr_inodes); |
| 71 | static DEFINE_PER_CPU(unsigned long, nr_unused); |
| 72 | |
| 73 | static struct kmem_cache *inode_cachep __ro_after_init; |
| 74 | |
| 75 | static long get_nr_inodes(void) |
| 76 | { |
| 77 | int i; |
| 78 | long sum = 0; |
| 79 | for_each_possible_cpu(i) |
| 80 | sum += per_cpu(nr_inodes, i); |
| 81 | return sum < 0 ? 0 : sum; |
| 82 | } |
| 83 | |
| 84 | static inline long get_nr_inodes_unused(void) |
| 85 | { |
| 86 | int i; |
| 87 | long sum = 0; |
| 88 | for_each_possible_cpu(i) |
| 89 | sum += per_cpu(nr_unused, i); |
| 90 | return sum < 0 ? 0 : sum; |
| 91 | } |
| 92 | |
| 93 | long get_nr_dirty_inodes(void) |
| 94 | { |
| 95 | /* not actually dirty inodes, but a wild approximation */ |
| 96 | long nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
| 97 | return nr_dirty > 0 ? nr_dirty : 0; |
| 98 | } |
| 99 | |
| 100 | /* |
| 101 | * Handle nr_inode sysctl |
| 102 | */ |
| 103 | #ifdef CONFIG_SYSCTL |
| 104 | /* |
| 105 | * Statistics gathering.. |
| 106 | */ |
| 107 | static struct inodes_stat_t inodes_stat; |
| 108 | |
| 109 | static int proc_nr_inodes(struct ctl_table *table, int write, void *buffer, |
| 110 | size_t *lenp, loff_t *ppos) |
| 111 | { |
| 112 | inodes_stat.nr_inodes = get_nr_inodes(); |
| 113 | inodes_stat.nr_unused = get_nr_inodes_unused(); |
| 114 | return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); |
| 115 | } |
| 116 | |
| 117 | static struct ctl_table inodes_sysctls[] = { |
| 118 | { |
| 119 | .procname = "inode-nr", |
| 120 | .data = &inodes_stat, |
| 121 | .maxlen = 2*sizeof(long), |
| 122 | .mode = 0444, |
| 123 | .proc_handler = proc_nr_inodes, |
| 124 | }, |
| 125 | { |
| 126 | .procname = "inode-state", |
| 127 | .data = &inodes_stat, |
| 128 | .maxlen = 7*sizeof(long), |
| 129 | .mode = 0444, |
| 130 | .proc_handler = proc_nr_inodes, |
| 131 | }, |
| 132 | { } |
| 133 | }; |
| 134 | |
| 135 | static int __init init_fs_inode_sysctls(void) |
| 136 | { |
| 137 | register_sysctl_init("fs", inodes_sysctls); |
| 138 | return 0; |
| 139 | } |
| 140 | early_initcall(init_fs_inode_sysctls); |
| 141 | #endif |
| 142 | |
| 143 | static int no_open(struct inode *inode, struct file *file) |
| 144 | { |
| 145 | return -ENXIO; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * inode_init_always - perform inode structure initialisation |
| 150 | * @sb: superblock inode belongs to |
| 151 | * @inode: inode to initialise |
| 152 | * |
| 153 | * These are initializations that need to be done on every inode |
| 154 | * allocation as the fields are not initialised by slab allocation. |
| 155 | */ |
| 156 | int inode_init_always(struct super_block *sb, struct inode *inode) |
| 157 | { |
| 158 | static const struct inode_operations empty_iops; |
| 159 | static const struct file_operations no_open_fops = {.open = no_open}; |
| 160 | struct address_space *const mapping = &inode->i_data; |
| 161 | |
| 162 | inode->i_sb = sb; |
| 163 | inode->i_blkbits = sb->s_blocksize_bits; |
| 164 | inode->i_flags = 0; |
| 165 | atomic64_set(&inode->i_sequence, 0); |
| 166 | atomic_set(&inode->i_count, 1); |
| 167 | inode->i_op = &empty_iops; |
| 168 | inode->i_fop = &no_open_fops; |
| 169 | inode->i_ino = 0; |
| 170 | inode->__i_nlink = 1; |
| 171 | inode->i_opflags = 0; |
| 172 | if (sb->s_xattr) |
| 173 | inode->i_opflags |= IOP_XATTR; |
| 174 | i_uid_write(inode, 0); |
| 175 | i_gid_write(inode, 0); |
| 176 | atomic_set(&inode->i_writecount, 0); |
| 177 | inode->i_size = 0; |
| 178 | inode->i_write_hint = WRITE_LIFE_NOT_SET; |
| 179 | inode->i_blocks = 0; |
| 180 | inode->i_bytes = 0; |
| 181 | inode->i_generation = 0; |
| 182 | inode->i_pipe = NULL; |
| 183 | inode->i_cdev = NULL; |
| 184 | inode->i_link = NULL; |
| 185 | inode->i_dir_seq = 0; |
| 186 | inode->i_rdev = 0; |
| 187 | inode->dirtied_when = 0; |
| 188 | |
| 189 | #ifdef CONFIG_CGROUP_WRITEBACK |
| 190 | inode->i_wb_frn_winner = 0; |
| 191 | inode->i_wb_frn_avg_time = 0; |
| 192 | inode->i_wb_frn_history = 0; |
| 193 | #endif |
| 194 | |
| 195 | spin_lock_init(&inode->i_lock); |
| 196 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
| 197 | |
| 198 | init_rwsem(&inode->i_rwsem); |
| 199 | lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); |
| 200 | |
| 201 | atomic_set(&inode->i_dio_count, 0); |
| 202 | |
| 203 | mapping->a_ops = &empty_aops; |
| 204 | mapping->host = inode; |
| 205 | mapping->flags = 0; |
| 206 | mapping->wb_err = 0; |
| 207 | atomic_set(&mapping->i_mmap_writable, 0); |
| 208 | #ifdef CONFIG_READ_ONLY_THP_FOR_FS |
| 209 | atomic_set(&mapping->nr_thps, 0); |
| 210 | #endif |
| 211 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
| 212 | mapping->private_data = NULL; |
| 213 | mapping->writeback_index = 0; |
| 214 | init_rwsem(&mapping->invalidate_lock); |
| 215 | lockdep_set_class_and_name(&mapping->invalidate_lock, |
| 216 | &sb->s_type->invalidate_lock_key, |
| 217 | "mapping.invalidate_lock"); |
| 218 | inode->i_private = NULL; |
| 219 | inode->i_mapping = mapping; |
| 220 | INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ |
| 221 | #ifdef CONFIG_FS_POSIX_ACL |
| 222 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
| 223 | #endif |
| 224 | |
| 225 | #ifdef CONFIG_FSNOTIFY |
| 226 | inode->i_fsnotify_mask = 0; |
| 227 | #endif |
| 228 | inode->i_flctx = NULL; |
| 229 | |
| 230 | if (unlikely(security_inode_alloc(inode))) |
| 231 | return -ENOMEM; |
| 232 | this_cpu_inc(nr_inodes); |
| 233 | |
| 234 | return 0; |
| 235 | } |
| 236 | EXPORT_SYMBOL(inode_init_always); |
| 237 | |
| 238 | void free_inode_nonrcu(struct inode *inode) |
| 239 | { |
| 240 | kmem_cache_free(inode_cachep, inode); |
| 241 | } |
| 242 | EXPORT_SYMBOL(free_inode_nonrcu); |
| 243 | |
| 244 | static void i_callback(struct rcu_head *head) |
| 245 | { |
| 246 | struct inode *inode = container_of(head, struct inode, i_rcu); |
| 247 | if (inode->free_inode) |
| 248 | inode->free_inode(inode); |
| 249 | else |
| 250 | free_inode_nonrcu(inode); |
| 251 | } |
| 252 | |
| 253 | static struct inode *alloc_inode(struct super_block *sb) |
| 254 | { |
| 255 | const struct super_operations *ops = sb->s_op; |
| 256 | struct inode *inode; |
| 257 | |
| 258 | if (ops->alloc_inode) |
| 259 | inode = ops->alloc_inode(sb); |
| 260 | else |
| 261 | inode = alloc_inode_sb(sb, inode_cachep, GFP_KERNEL); |
| 262 | |
| 263 | if (!inode) |
| 264 | return NULL; |
| 265 | |
| 266 | if (unlikely(inode_init_always(sb, inode))) { |
| 267 | if (ops->destroy_inode) { |
| 268 | ops->destroy_inode(inode); |
| 269 | if (!ops->free_inode) |
| 270 | return NULL; |
| 271 | } |
| 272 | inode->free_inode = ops->free_inode; |
| 273 | i_callback(&inode->i_rcu); |
| 274 | return NULL; |
| 275 | } |
| 276 | |
| 277 | return inode; |
| 278 | } |
| 279 | |
| 280 | void __destroy_inode(struct inode *inode) |
| 281 | { |
| 282 | BUG_ON(inode_has_buffers(inode)); |
| 283 | inode_detach_wb(inode); |
| 284 | security_inode_free(inode); |
| 285 | fsnotify_inode_delete(inode); |
| 286 | locks_free_lock_context(inode); |
| 287 | if (!inode->i_nlink) { |
| 288 | WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); |
| 289 | atomic_long_dec(&inode->i_sb->s_remove_count); |
| 290 | } |
| 291 | |
| 292 | #ifdef CONFIG_FS_POSIX_ACL |
| 293 | if (inode->i_acl && !is_uncached_acl(inode->i_acl)) |
| 294 | posix_acl_release(inode->i_acl); |
| 295 | if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl)) |
| 296 | posix_acl_release(inode->i_default_acl); |
| 297 | #endif |
| 298 | this_cpu_dec(nr_inodes); |
| 299 | } |
| 300 | EXPORT_SYMBOL(__destroy_inode); |
| 301 | |
| 302 | static void destroy_inode(struct inode *inode) |
| 303 | { |
| 304 | const struct super_operations *ops = inode->i_sb->s_op; |
| 305 | |
| 306 | BUG_ON(!list_empty(&inode->i_lru)); |
| 307 | __destroy_inode(inode); |
| 308 | if (ops->destroy_inode) { |
| 309 | ops->destroy_inode(inode); |
| 310 | if (!ops->free_inode) |
| 311 | return; |
| 312 | } |
| 313 | inode->free_inode = ops->free_inode; |
| 314 | call_rcu(&inode->i_rcu, i_callback); |
| 315 | } |
| 316 | |
| 317 | /** |
| 318 | * drop_nlink - directly drop an inode's link count |
| 319 | * @inode: inode |
| 320 | * |
| 321 | * This is a low-level filesystem helper to replace any |
| 322 | * direct filesystem manipulation of i_nlink. In cases |
| 323 | * where we are attempting to track writes to the |
| 324 | * filesystem, a decrement to zero means an imminent |
| 325 | * write when the file is truncated and actually unlinked |
| 326 | * on the filesystem. |
| 327 | */ |
| 328 | void drop_nlink(struct inode *inode) |
| 329 | { |
| 330 | WARN_ON(inode->i_nlink == 0); |
| 331 | inode->__i_nlink--; |
| 332 | if (!inode->i_nlink) |
| 333 | atomic_long_inc(&inode->i_sb->s_remove_count); |
| 334 | } |
| 335 | EXPORT_SYMBOL(drop_nlink); |
| 336 | |
| 337 | /** |
| 338 | * clear_nlink - directly zero an inode's link count |
| 339 | * @inode: inode |
| 340 | * |
| 341 | * This is a low-level filesystem helper to replace any |
| 342 | * direct filesystem manipulation of i_nlink. See |
| 343 | * drop_nlink() for why we care about i_nlink hitting zero. |
| 344 | */ |
| 345 | void clear_nlink(struct inode *inode) |
| 346 | { |
| 347 | if (inode->i_nlink) { |
| 348 | inode->__i_nlink = 0; |
| 349 | atomic_long_inc(&inode->i_sb->s_remove_count); |
| 350 | } |
| 351 | } |
| 352 | EXPORT_SYMBOL(clear_nlink); |
| 353 | |
| 354 | /** |
| 355 | * set_nlink - directly set an inode's link count |
| 356 | * @inode: inode |
| 357 | * @nlink: new nlink (should be non-zero) |
| 358 | * |
| 359 | * This is a low-level filesystem helper to replace any |
| 360 | * direct filesystem manipulation of i_nlink. |
| 361 | */ |
| 362 | void set_nlink(struct inode *inode, unsigned int nlink) |
| 363 | { |
| 364 | if (!nlink) { |
| 365 | clear_nlink(inode); |
| 366 | } else { |
| 367 | /* Yes, some filesystems do change nlink from zero to one */ |
| 368 | if (inode->i_nlink == 0) |
| 369 | atomic_long_dec(&inode->i_sb->s_remove_count); |
| 370 | |
| 371 | inode->__i_nlink = nlink; |
| 372 | } |
| 373 | } |
| 374 | EXPORT_SYMBOL(set_nlink); |
| 375 | |
| 376 | /** |
| 377 | * inc_nlink - directly increment an inode's link count |
| 378 | * @inode: inode |
| 379 | * |
| 380 | * This is a low-level filesystem helper to replace any |
| 381 | * direct filesystem manipulation of i_nlink. Currently, |
| 382 | * it is only here for parity with dec_nlink(). |
| 383 | */ |
| 384 | void inc_nlink(struct inode *inode) |
| 385 | { |
| 386 | if (unlikely(inode->i_nlink == 0)) { |
| 387 | WARN_ON(!(inode->i_state & I_LINKABLE)); |
| 388 | atomic_long_dec(&inode->i_sb->s_remove_count); |
| 389 | } |
| 390 | |
| 391 | inode->__i_nlink++; |
| 392 | } |
| 393 | EXPORT_SYMBOL(inc_nlink); |
| 394 | |
| 395 | static void __address_space_init_once(struct address_space *mapping) |
| 396 | { |
| 397 | xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT); |
| 398 | init_rwsem(&mapping->i_mmap_rwsem); |
| 399 | INIT_LIST_HEAD(&mapping->private_list); |
| 400 | spin_lock_init(&mapping->private_lock); |
| 401 | mapping->i_mmap = RB_ROOT_CACHED; |
| 402 | } |
| 403 | |
| 404 | void address_space_init_once(struct address_space *mapping) |
| 405 | { |
| 406 | memset(mapping, 0, sizeof(*mapping)); |
| 407 | __address_space_init_once(mapping); |
| 408 | } |
| 409 | EXPORT_SYMBOL(address_space_init_once); |
| 410 | |
| 411 | /* |
| 412 | * These are initializations that only need to be done |
| 413 | * once, because the fields are idempotent across use |
| 414 | * of the inode, so let the slab aware of that. |
| 415 | */ |
| 416 | void inode_init_once(struct inode *inode) |
| 417 | { |
| 418 | memset(inode, 0, sizeof(*inode)); |
| 419 | INIT_HLIST_NODE(&inode->i_hash); |
| 420 | INIT_LIST_HEAD(&inode->i_devices); |
| 421 | INIT_LIST_HEAD(&inode->i_io_list); |
| 422 | INIT_LIST_HEAD(&inode->i_wb_list); |
| 423 | INIT_LIST_HEAD(&inode->i_lru); |
| 424 | INIT_LIST_HEAD(&inode->i_sb_list); |
| 425 | __address_space_init_once(&inode->i_data); |
| 426 | i_size_ordered_init(inode); |
| 427 | } |
| 428 | EXPORT_SYMBOL(inode_init_once); |
| 429 | |
| 430 | static void init_once(void *foo) |
| 431 | { |
| 432 | struct inode *inode = (struct inode *) foo; |
| 433 | |
| 434 | inode_init_once(inode); |
| 435 | } |
| 436 | |
| 437 | /* |
| 438 | * inode->i_lock must be held |
| 439 | */ |
| 440 | void __iget(struct inode *inode) |
| 441 | { |
| 442 | atomic_inc(&inode->i_count); |
| 443 | } |
| 444 | |
| 445 | /* |
| 446 | * get additional reference to inode; caller must already hold one. |
| 447 | */ |
| 448 | void ihold(struct inode *inode) |
| 449 | { |
| 450 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
| 451 | } |
| 452 | EXPORT_SYMBOL(ihold); |
| 453 | |
| 454 | static void __inode_add_lru(struct inode *inode, bool rotate) |
| 455 | { |
| 456 | if (inode->i_state & (I_DIRTY_ALL | I_SYNC | I_FREEING | I_WILL_FREE)) |
| 457 | return; |
| 458 | if (atomic_read(&inode->i_count)) |
| 459 | return; |
| 460 | if (!(inode->i_sb->s_flags & SB_ACTIVE)) |
| 461 | return; |
| 462 | if (!mapping_shrinkable(&inode->i_data)) |
| 463 | return; |
| 464 | |
| 465 | if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
| 466 | this_cpu_inc(nr_unused); |
| 467 | else if (rotate) |
| 468 | inode->i_state |= I_REFERENCED; |
| 469 | } |
| 470 | |
| 471 | /* |
| 472 | * Add inode to LRU if needed (inode is unused and clean). |
| 473 | * |
| 474 | * Needs inode->i_lock held. |
| 475 | */ |
| 476 | void inode_add_lru(struct inode *inode) |
| 477 | { |
| 478 | __inode_add_lru(inode, false); |
| 479 | } |
| 480 | |
| 481 | static void inode_lru_list_del(struct inode *inode) |
| 482 | { |
| 483 | if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
| 484 | this_cpu_dec(nr_unused); |
| 485 | } |
| 486 | |
| 487 | /** |
| 488 | * inode_sb_list_add - add inode to the superblock list of inodes |
| 489 | * @inode: inode to add |
| 490 | */ |
| 491 | void inode_sb_list_add(struct inode *inode) |
| 492 | { |
| 493 | spin_lock(&inode->i_sb->s_inode_list_lock); |
| 494 | list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
| 495 | spin_unlock(&inode->i_sb->s_inode_list_lock); |
| 496 | } |
| 497 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
| 498 | |
| 499 | static inline void inode_sb_list_del(struct inode *inode) |
| 500 | { |
| 501 | if (!list_empty(&inode->i_sb_list)) { |
| 502 | spin_lock(&inode->i_sb->s_inode_list_lock); |
| 503 | list_del_init(&inode->i_sb_list); |
| 504 | spin_unlock(&inode->i_sb->s_inode_list_lock); |
| 505 | } |
| 506 | } |
| 507 | |
| 508 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
| 509 | { |
| 510 | unsigned long tmp; |
| 511 | |
| 512 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
| 513 | L1_CACHE_BYTES; |
| 514 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
| 515 | return tmp & i_hash_mask; |
| 516 | } |
| 517 | |
| 518 | /** |
| 519 | * __insert_inode_hash - hash an inode |
| 520 | * @inode: unhashed inode |
| 521 | * @hashval: unsigned long value used to locate this object in the |
| 522 | * inode_hashtable. |
| 523 | * |
| 524 | * Add an inode to the inode hash for this superblock. |
| 525 | */ |
| 526 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
| 527 | { |
| 528 | struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
| 529 | |
| 530 | spin_lock(&inode_hash_lock); |
| 531 | spin_lock(&inode->i_lock); |
| 532 | hlist_add_head_rcu(&inode->i_hash, b); |
| 533 | spin_unlock(&inode->i_lock); |
| 534 | spin_unlock(&inode_hash_lock); |
| 535 | } |
| 536 | EXPORT_SYMBOL(__insert_inode_hash); |
| 537 | |
| 538 | /** |
| 539 | * __remove_inode_hash - remove an inode from the hash |
| 540 | * @inode: inode to unhash |
| 541 | * |
| 542 | * Remove an inode from the superblock. |
| 543 | */ |
| 544 | void __remove_inode_hash(struct inode *inode) |
| 545 | { |
| 546 | spin_lock(&inode_hash_lock); |
| 547 | spin_lock(&inode->i_lock); |
| 548 | hlist_del_init_rcu(&inode->i_hash); |
| 549 | spin_unlock(&inode->i_lock); |
| 550 | spin_unlock(&inode_hash_lock); |
| 551 | } |
| 552 | EXPORT_SYMBOL(__remove_inode_hash); |
| 553 | |
| 554 | void dump_mapping(const struct address_space *mapping) |
| 555 | { |
| 556 | struct inode *host; |
| 557 | const struct address_space_operations *a_ops; |
| 558 | struct hlist_node *dentry_first; |
| 559 | struct dentry *dentry_ptr; |
| 560 | struct dentry dentry; |
| 561 | unsigned long ino; |
| 562 | |
| 563 | /* |
| 564 | * If mapping is an invalid pointer, we don't want to crash |
| 565 | * accessing it, so probe everything depending on it carefully. |
| 566 | */ |
| 567 | if (get_kernel_nofault(host, &mapping->host) || |
| 568 | get_kernel_nofault(a_ops, &mapping->a_ops)) { |
| 569 | pr_warn("invalid mapping:%px\n", mapping); |
| 570 | return; |
| 571 | } |
| 572 | |
| 573 | if (!host) { |
| 574 | pr_warn("aops:%ps\n", a_ops); |
| 575 | return; |
| 576 | } |
| 577 | |
| 578 | if (get_kernel_nofault(dentry_first, &host->i_dentry.first) || |
| 579 | get_kernel_nofault(ino, &host->i_ino)) { |
| 580 | pr_warn("aops:%ps invalid inode:%px\n", a_ops, host); |
| 581 | return; |
| 582 | } |
| 583 | |
| 584 | if (!dentry_first) { |
| 585 | pr_warn("aops:%ps ino:%lx\n", a_ops, ino); |
| 586 | return; |
| 587 | } |
| 588 | |
| 589 | dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); |
| 590 | if (get_kernel_nofault(dentry, dentry_ptr)) { |
| 591 | pr_warn("aops:%ps ino:%lx invalid dentry:%px\n", |
| 592 | a_ops, ino, dentry_ptr); |
| 593 | return; |
| 594 | } |
| 595 | |
| 596 | /* |
| 597 | * if dentry is corrupted, the %pd handler may still crash, |
| 598 | * but it's unlikely that we reach here with a corrupt mapping |
| 599 | */ |
| 600 | pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry); |
| 601 | } |
| 602 | |
| 603 | void clear_inode(struct inode *inode) |
| 604 | { |
| 605 | /* |
| 606 | * We have to cycle the i_pages lock here because reclaim can be in the |
| 607 | * process of removing the last page (in __filemap_remove_folio()) |
| 608 | * and we must not free the mapping under it. |
| 609 | */ |
| 610 | xa_lock_irq(&inode->i_data.i_pages); |
| 611 | BUG_ON(inode->i_data.nrpages); |
| 612 | /* |
| 613 | * Almost always, mapping_empty(&inode->i_data) here; but there are |
| 614 | * two known and long-standing ways in which nodes may get left behind |
| 615 | * (when deep radix-tree node allocation failed partway; or when THP |
| 616 | * collapse_file() failed). Until those two known cases are cleaned up, |
| 617 | * or a cleanup function is called here, do not BUG_ON(!mapping_empty), |
| 618 | * nor even WARN_ON(!mapping_empty). |
| 619 | */ |
| 620 | xa_unlock_irq(&inode->i_data.i_pages); |
| 621 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
| 622 | BUG_ON(!(inode->i_state & I_FREEING)); |
| 623 | BUG_ON(inode->i_state & I_CLEAR); |
| 624 | BUG_ON(!list_empty(&inode->i_wb_list)); |
| 625 | /* don't need i_lock here, no concurrent mods to i_state */ |
| 626 | inode->i_state = I_FREEING | I_CLEAR; |
| 627 | } |
| 628 | EXPORT_SYMBOL(clear_inode); |
| 629 | |
| 630 | /* |
| 631 | * Free the inode passed in, removing it from the lists it is still connected |
| 632 | * to. We remove any pages still attached to the inode and wait for any IO that |
| 633 | * is still in progress before finally destroying the inode. |
| 634 | * |
| 635 | * An inode must already be marked I_FREEING so that we avoid the inode being |
| 636 | * moved back onto lists if we race with other code that manipulates the lists |
| 637 | * (e.g. writeback_single_inode). The caller is responsible for setting this. |
| 638 | * |
| 639 | * An inode must already be removed from the LRU list before being evicted from |
| 640 | * the cache. This should occur atomically with setting the I_FREEING state |
| 641 | * flag, so no inodes here should ever be on the LRU when being evicted. |
| 642 | */ |
| 643 | static void evict(struct inode *inode) |
| 644 | { |
| 645 | const struct super_operations *op = inode->i_sb->s_op; |
| 646 | |
| 647 | BUG_ON(!(inode->i_state & I_FREEING)); |
| 648 | BUG_ON(!list_empty(&inode->i_lru)); |
| 649 | |
| 650 | if (!list_empty(&inode->i_io_list)) |
| 651 | inode_io_list_del(inode); |
| 652 | |
| 653 | inode_sb_list_del(inode); |
| 654 | |
| 655 | /* |
| 656 | * Wait for flusher thread to be done with the inode so that filesystem |
| 657 | * does not start destroying it while writeback is still running. Since |
| 658 | * the inode has I_FREEING set, flusher thread won't start new work on |
| 659 | * the inode. We just have to wait for running writeback to finish. |
| 660 | */ |
| 661 | inode_wait_for_writeback(inode); |
| 662 | |
| 663 | if (op->evict_inode) { |
| 664 | op->evict_inode(inode); |
| 665 | } else { |
| 666 | truncate_inode_pages_final(&inode->i_data); |
| 667 | clear_inode(inode); |
| 668 | } |
| 669 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
| 670 | cd_forget(inode); |
| 671 | |
| 672 | remove_inode_hash(inode); |
| 673 | |
| 674 | spin_lock(&inode->i_lock); |
| 675 | wake_up_bit(&inode->i_state, __I_NEW); |
| 676 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
| 677 | spin_unlock(&inode->i_lock); |
| 678 | |
| 679 | destroy_inode(inode); |
| 680 | } |
| 681 | |
| 682 | /* |
| 683 | * dispose_list - dispose of the contents of a local list |
| 684 | * @head: the head of the list to free |
| 685 | * |
| 686 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
| 687 | * need to worry about list corruption and SMP locks. |
| 688 | */ |
| 689 | static void dispose_list(struct list_head *head) |
| 690 | { |
| 691 | while (!list_empty(head)) { |
| 692 | struct inode *inode; |
| 693 | |
| 694 | inode = list_first_entry(head, struct inode, i_lru); |
| 695 | list_del_init(&inode->i_lru); |
| 696 | |
| 697 | evict(inode); |
| 698 | cond_resched(); |
| 699 | } |
| 700 | } |
| 701 | |
| 702 | /** |
| 703 | * evict_inodes - evict all evictable inodes for a superblock |
| 704 | * @sb: superblock to operate on |
| 705 | * |
| 706 | * Make sure that no inodes with zero refcount are retained. This is |
| 707 | * called by superblock shutdown after having SB_ACTIVE flag removed, |
| 708 | * so any inode reaching zero refcount during or after that call will |
| 709 | * be immediately evicted. |
| 710 | */ |
| 711 | void evict_inodes(struct super_block *sb) |
| 712 | { |
| 713 | struct inode *inode, *next; |
| 714 | LIST_HEAD(dispose); |
| 715 | |
| 716 | again: |
| 717 | spin_lock(&sb->s_inode_list_lock); |
| 718 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
| 719 | if (atomic_read(&inode->i_count)) |
| 720 | continue; |
| 721 | |
| 722 | spin_lock(&inode->i_lock); |
| 723 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| 724 | spin_unlock(&inode->i_lock); |
| 725 | continue; |
| 726 | } |
| 727 | |
| 728 | inode->i_state |= I_FREEING; |
| 729 | inode_lru_list_del(inode); |
| 730 | spin_unlock(&inode->i_lock); |
| 731 | list_add(&inode->i_lru, &dispose); |
| 732 | |
| 733 | /* |
| 734 | * We can have a ton of inodes to evict at unmount time given |
| 735 | * enough memory, check to see if we need to go to sleep for a |
| 736 | * bit so we don't livelock. |
| 737 | */ |
| 738 | if (need_resched()) { |
| 739 | spin_unlock(&sb->s_inode_list_lock); |
| 740 | cond_resched(); |
| 741 | dispose_list(&dispose); |
| 742 | goto again; |
| 743 | } |
| 744 | } |
| 745 | spin_unlock(&sb->s_inode_list_lock); |
| 746 | |
| 747 | dispose_list(&dispose); |
| 748 | } |
| 749 | EXPORT_SYMBOL_GPL(evict_inodes); |
| 750 | |
| 751 | /** |
| 752 | * invalidate_inodes - attempt to free all inodes on a superblock |
| 753 | * @sb: superblock to operate on |
| 754 | * |
| 755 | * Attempts to free all inodes (including dirty inodes) for a given superblock. |
| 756 | */ |
| 757 | void invalidate_inodes(struct super_block *sb) |
| 758 | { |
| 759 | struct inode *inode, *next; |
| 760 | LIST_HEAD(dispose); |
| 761 | |
| 762 | again: |
| 763 | spin_lock(&sb->s_inode_list_lock); |
| 764 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
| 765 | spin_lock(&inode->i_lock); |
| 766 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| 767 | spin_unlock(&inode->i_lock); |
| 768 | continue; |
| 769 | } |
| 770 | if (atomic_read(&inode->i_count)) { |
| 771 | spin_unlock(&inode->i_lock); |
| 772 | continue; |
| 773 | } |
| 774 | |
| 775 | inode->i_state |= I_FREEING; |
| 776 | inode_lru_list_del(inode); |
| 777 | spin_unlock(&inode->i_lock); |
| 778 | list_add(&inode->i_lru, &dispose); |
| 779 | if (need_resched()) { |
| 780 | spin_unlock(&sb->s_inode_list_lock); |
| 781 | cond_resched(); |
| 782 | dispose_list(&dispose); |
| 783 | goto again; |
| 784 | } |
| 785 | } |
| 786 | spin_unlock(&sb->s_inode_list_lock); |
| 787 | |
| 788 | dispose_list(&dispose); |
| 789 | } |
| 790 | |
| 791 | /* |
| 792 | * Isolate the inode from the LRU in preparation for freeing it. |
| 793 | * |
| 794 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
| 795 | * used recently - the flag is set in iput_final(). When we encounter such an |
| 796 | * inode, clear the flag and move it to the back of the LRU so it gets another |
| 797 | * pass through the LRU before it gets reclaimed. This is necessary because of |
| 798 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
| 799 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
| 800 | * with this flag set because they are the inodes that are out of order. |
| 801 | */ |
| 802 | static enum lru_status inode_lru_isolate(struct list_head *item, |
| 803 | struct list_lru_one *lru, spinlock_t *lru_lock, void *arg) |
| 804 | { |
| 805 | struct list_head *freeable = arg; |
| 806 | struct inode *inode = container_of(item, struct inode, i_lru); |
| 807 | |
| 808 | /* |
| 809 | * We are inverting the lru lock/inode->i_lock here, so use a |
| 810 | * trylock. If we fail to get the lock, just skip it. |
| 811 | */ |
| 812 | if (!spin_trylock(&inode->i_lock)) |
| 813 | return LRU_SKIP; |
| 814 | |
| 815 | /* |
| 816 | * Inodes can get referenced, redirtied, or repopulated while |
| 817 | * they're already on the LRU, and this can make them |
| 818 | * unreclaimable for a while. Remove them lazily here; iput, |
| 819 | * sync, or the last page cache deletion will requeue them. |
| 820 | */ |
| 821 | if (atomic_read(&inode->i_count) || |
| 822 | (inode->i_state & ~I_REFERENCED) || |
| 823 | !mapping_shrinkable(&inode->i_data)) { |
| 824 | list_lru_isolate(lru, &inode->i_lru); |
| 825 | spin_unlock(&inode->i_lock); |
| 826 | this_cpu_dec(nr_unused); |
| 827 | return LRU_REMOVED; |
| 828 | } |
| 829 | |
| 830 | /* Recently referenced inodes get one more pass */ |
| 831 | if (inode->i_state & I_REFERENCED) { |
| 832 | inode->i_state &= ~I_REFERENCED; |
| 833 | spin_unlock(&inode->i_lock); |
| 834 | return LRU_ROTATE; |
| 835 | } |
| 836 | |
| 837 | /* |
| 838 | * On highmem systems, mapping_shrinkable() permits dropping |
| 839 | * page cache in order to free up struct inodes: lowmem might |
| 840 | * be under pressure before the cache inside the highmem zone. |
| 841 | */ |
| 842 | if (inode_has_buffers(inode) || !mapping_empty(&inode->i_data)) { |
| 843 | __iget(inode); |
| 844 | spin_unlock(&inode->i_lock); |
| 845 | spin_unlock(lru_lock); |
| 846 | if (remove_inode_buffers(inode)) { |
| 847 | unsigned long reap; |
| 848 | reap = invalidate_mapping_pages(&inode->i_data, 0, -1); |
| 849 | if (current_is_kswapd()) |
| 850 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
| 851 | else |
| 852 | __count_vm_events(PGINODESTEAL, reap); |
| 853 | mm_account_reclaimed_pages(reap); |
| 854 | } |
| 855 | iput(inode); |
| 856 | spin_lock(lru_lock); |
| 857 | return LRU_RETRY; |
| 858 | } |
| 859 | |
| 860 | WARN_ON(inode->i_state & I_NEW); |
| 861 | inode->i_state |= I_FREEING; |
| 862 | list_lru_isolate_move(lru, &inode->i_lru, freeable); |
| 863 | spin_unlock(&inode->i_lock); |
| 864 | |
| 865 | this_cpu_dec(nr_unused); |
| 866 | return LRU_REMOVED; |
| 867 | } |
| 868 | |
| 869 | /* |
| 870 | * Walk the superblock inode LRU for freeable inodes and attempt to free them. |
| 871 | * This is called from the superblock shrinker function with a number of inodes |
| 872 | * to trim from the LRU. Inodes to be freed are moved to a temporary list and |
| 873 | * then are freed outside inode_lock by dispose_list(). |
| 874 | */ |
| 875 | long prune_icache_sb(struct super_block *sb, struct shrink_control *sc) |
| 876 | { |
| 877 | LIST_HEAD(freeable); |
| 878 | long freed; |
| 879 | |
| 880 | freed = list_lru_shrink_walk(&sb->s_inode_lru, sc, |
| 881 | inode_lru_isolate, &freeable); |
| 882 | dispose_list(&freeable); |
| 883 | return freed; |
| 884 | } |
| 885 | |
| 886 | static void __wait_on_freeing_inode(struct inode *inode); |
| 887 | /* |
| 888 | * Called with the inode lock held. |
| 889 | */ |
| 890 | static struct inode *find_inode(struct super_block *sb, |
| 891 | struct hlist_head *head, |
| 892 | int (*test)(struct inode *, void *), |
| 893 | void *data) |
| 894 | { |
| 895 | struct inode *inode = NULL; |
| 896 | |
| 897 | repeat: |
| 898 | hlist_for_each_entry(inode, head, i_hash) { |
| 899 | if (inode->i_sb != sb) |
| 900 | continue; |
| 901 | if (!test(inode, data)) |
| 902 | continue; |
| 903 | spin_lock(&inode->i_lock); |
| 904 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
| 905 | __wait_on_freeing_inode(inode); |
| 906 | goto repeat; |
| 907 | } |
| 908 | if (unlikely(inode->i_state & I_CREATING)) { |
| 909 | spin_unlock(&inode->i_lock); |
| 910 | return ERR_PTR(-ESTALE); |
| 911 | } |
| 912 | __iget(inode); |
| 913 | spin_unlock(&inode->i_lock); |
| 914 | return inode; |
| 915 | } |
| 916 | return NULL; |
| 917 | } |
| 918 | |
| 919 | /* |
| 920 | * find_inode_fast is the fast path version of find_inode, see the comment at |
| 921 | * iget_locked for details. |
| 922 | */ |
| 923 | static struct inode *find_inode_fast(struct super_block *sb, |
| 924 | struct hlist_head *head, unsigned long ino) |
| 925 | { |
| 926 | struct inode *inode = NULL; |
| 927 | |
| 928 | repeat: |
| 929 | hlist_for_each_entry(inode, head, i_hash) { |
| 930 | if (inode->i_ino != ino) |
| 931 | continue; |
| 932 | if (inode->i_sb != sb) |
| 933 | continue; |
| 934 | spin_lock(&inode->i_lock); |
| 935 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
| 936 | __wait_on_freeing_inode(inode); |
| 937 | goto repeat; |
| 938 | } |
| 939 | if (unlikely(inode->i_state & I_CREATING)) { |
| 940 | spin_unlock(&inode->i_lock); |
| 941 | return ERR_PTR(-ESTALE); |
| 942 | } |
| 943 | __iget(inode); |
| 944 | spin_unlock(&inode->i_lock); |
| 945 | return inode; |
| 946 | } |
| 947 | return NULL; |
| 948 | } |
| 949 | |
| 950 | /* |
| 951 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
| 952 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
| 953 | * to renew the exhausted range. |
| 954 | * |
| 955 | * This does not significantly increase overflow rate because every CPU can |
| 956 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
| 957 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
| 958 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
| 959 | * overflow rate by 2x, which does not seem too significant. |
| 960 | * |
| 961 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
| 962 | * error if st_ino won't fit in target struct field. Use 32bit counter |
| 963 | * here to attempt to avoid that. |
| 964 | */ |
| 965 | #define LAST_INO_BATCH 1024 |
| 966 | static DEFINE_PER_CPU(unsigned int, last_ino); |
| 967 | |
| 968 | unsigned int get_next_ino(void) |
| 969 | { |
| 970 | unsigned int *p = &get_cpu_var(last_ino); |
| 971 | unsigned int res = *p; |
| 972 | |
| 973 | #ifdef CONFIG_SMP |
| 974 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
| 975 | static atomic_t shared_last_ino; |
| 976 | int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
| 977 | |
| 978 | res = next - LAST_INO_BATCH; |
| 979 | } |
| 980 | #endif |
| 981 | |
| 982 | res++; |
| 983 | /* get_next_ino should not provide a 0 inode number */ |
| 984 | if (unlikely(!res)) |
| 985 | res++; |
| 986 | *p = res; |
| 987 | put_cpu_var(last_ino); |
| 988 | return res; |
| 989 | } |
| 990 | EXPORT_SYMBOL(get_next_ino); |
| 991 | |
| 992 | /** |
| 993 | * new_inode_pseudo - obtain an inode |
| 994 | * @sb: superblock |
| 995 | * |
| 996 | * Allocates a new inode for given superblock. |
| 997 | * Inode wont be chained in superblock s_inodes list |
| 998 | * This means : |
| 999 | * - fs can't be unmount |
| 1000 | * - quotas, fsnotify, writeback can't work |
| 1001 | */ |
| 1002 | struct inode *new_inode_pseudo(struct super_block *sb) |
| 1003 | { |
| 1004 | struct inode *inode = alloc_inode(sb); |
| 1005 | |
| 1006 | if (inode) { |
| 1007 | spin_lock(&inode->i_lock); |
| 1008 | inode->i_state = 0; |
| 1009 | spin_unlock(&inode->i_lock); |
| 1010 | } |
| 1011 | return inode; |
| 1012 | } |
| 1013 | |
| 1014 | /** |
| 1015 | * new_inode - obtain an inode |
| 1016 | * @sb: superblock |
| 1017 | * |
| 1018 | * Allocates a new inode for given superblock. The default gfp_mask |
| 1019 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
| 1020 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
| 1021 | * for the page cache are not reclaimable or migratable, |
| 1022 | * mapping_set_gfp_mask() must be called with suitable flags on the |
| 1023 | * newly created inode's mapping |
| 1024 | * |
| 1025 | */ |
| 1026 | struct inode *new_inode(struct super_block *sb) |
| 1027 | { |
| 1028 | struct inode *inode; |
| 1029 | |
| 1030 | inode = new_inode_pseudo(sb); |
| 1031 | if (inode) |
| 1032 | inode_sb_list_add(inode); |
| 1033 | return inode; |
| 1034 | } |
| 1035 | EXPORT_SYMBOL(new_inode); |
| 1036 | |
| 1037 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 1038 | void lockdep_annotate_inode_mutex_key(struct inode *inode) |
| 1039 | { |
| 1040 | if (S_ISDIR(inode->i_mode)) { |
| 1041 | struct file_system_type *type = inode->i_sb->s_type; |
| 1042 | |
| 1043 | /* Set new key only if filesystem hasn't already changed it */ |
| 1044 | if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { |
| 1045 | /* |
| 1046 | * ensure nobody is actually holding i_mutex |
| 1047 | */ |
| 1048 | // mutex_destroy(&inode->i_mutex); |
| 1049 | init_rwsem(&inode->i_rwsem); |
| 1050 | lockdep_set_class(&inode->i_rwsem, |
| 1051 | &type->i_mutex_dir_key); |
| 1052 | } |
| 1053 | } |
| 1054 | } |
| 1055 | EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key); |
| 1056 | #endif |
| 1057 | |
| 1058 | /** |
| 1059 | * unlock_new_inode - clear the I_NEW state and wake up any waiters |
| 1060 | * @inode: new inode to unlock |
| 1061 | * |
| 1062 | * Called when the inode is fully initialised to clear the new state of the |
| 1063 | * inode and wake up anyone waiting for the inode to finish initialisation. |
| 1064 | */ |
| 1065 | void unlock_new_inode(struct inode *inode) |
| 1066 | { |
| 1067 | lockdep_annotate_inode_mutex_key(inode); |
| 1068 | spin_lock(&inode->i_lock); |
| 1069 | WARN_ON(!(inode->i_state & I_NEW)); |
| 1070 | inode->i_state &= ~I_NEW & ~I_CREATING; |
| 1071 | smp_mb(); |
| 1072 | wake_up_bit(&inode->i_state, __I_NEW); |
| 1073 | spin_unlock(&inode->i_lock); |
| 1074 | } |
| 1075 | EXPORT_SYMBOL(unlock_new_inode); |
| 1076 | |
| 1077 | void discard_new_inode(struct inode *inode) |
| 1078 | { |
| 1079 | lockdep_annotate_inode_mutex_key(inode); |
| 1080 | spin_lock(&inode->i_lock); |
| 1081 | WARN_ON(!(inode->i_state & I_NEW)); |
| 1082 | inode->i_state &= ~I_NEW; |
| 1083 | smp_mb(); |
| 1084 | wake_up_bit(&inode->i_state, __I_NEW); |
| 1085 | spin_unlock(&inode->i_lock); |
| 1086 | iput(inode); |
| 1087 | } |
| 1088 | EXPORT_SYMBOL(discard_new_inode); |
| 1089 | |
| 1090 | /** |
| 1091 | * lock_two_inodes - lock two inodes (may be regular files but also dirs) |
| 1092 | * |
| 1093 | * Lock any non-NULL argument. The caller must make sure that if he is passing |
| 1094 | * in two directories, one is not ancestor of the other. Zero, one or two |
| 1095 | * objects may be locked by this function. |
| 1096 | * |
| 1097 | * @inode1: first inode to lock |
| 1098 | * @inode2: second inode to lock |
| 1099 | * @subclass1: inode lock subclass for the first lock obtained |
| 1100 | * @subclass2: inode lock subclass for the second lock obtained |
| 1101 | */ |
| 1102 | void lock_two_inodes(struct inode *inode1, struct inode *inode2, |
| 1103 | unsigned subclass1, unsigned subclass2) |
| 1104 | { |
| 1105 | if (!inode1 || !inode2) { |
| 1106 | /* |
| 1107 | * Make sure @subclass1 will be used for the acquired lock. |
| 1108 | * This is not strictly necessary (no current caller cares) but |
| 1109 | * let's keep things consistent. |
| 1110 | */ |
| 1111 | if (!inode1) |
| 1112 | swap(inode1, inode2); |
| 1113 | goto lock; |
| 1114 | } |
| 1115 | |
| 1116 | /* |
| 1117 | * If one object is directory and the other is not, we must make sure |
| 1118 | * to lock directory first as the other object may be its child. |
| 1119 | */ |
| 1120 | if (S_ISDIR(inode2->i_mode) == S_ISDIR(inode1->i_mode)) { |
| 1121 | if (inode1 > inode2) |
| 1122 | swap(inode1, inode2); |
| 1123 | } else if (!S_ISDIR(inode1->i_mode)) |
| 1124 | swap(inode1, inode2); |
| 1125 | lock: |
| 1126 | if (inode1) |
| 1127 | inode_lock_nested(inode1, subclass1); |
| 1128 | if (inode2 && inode2 != inode1) |
| 1129 | inode_lock_nested(inode2, subclass2); |
| 1130 | } |
| 1131 | |
| 1132 | /** |
| 1133 | * lock_two_nondirectories - take two i_mutexes on non-directory objects |
| 1134 | * |
| 1135 | * Lock any non-NULL argument. Passed objects must not be directories. |
| 1136 | * Zero, one or two objects may be locked by this function. |
| 1137 | * |
| 1138 | * @inode1: first inode to lock |
| 1139 | * @inode2: second inode to lock |
| 1140 | */ |
| 1141 | void lock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
| 1142 | { |
| 1143 | if (inode1) |
| 1144 | WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); |
| 1145 | if (inode2) |
| 1146 | WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); |
| 1147 | lock_two_inodes(inode1, inode2, I_MUTEX_NORMAL, I_MUTEX_NONDIR2); |
| 1148 | } |
| 1149 | EXPORT_SYMBOL(lock_two_nondirectories); |
| 1150 | |
| 1151 | /** |
| 1152 | * unlock_two_nondirectories - release locks from lock_two_nondirectories() |
| 1153 | * @inode1: first inode to unlock |
| 1154 | * @inode2: second inode to unlock |
| 1155 | */ |
| 1156 | void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
| 1157 | { |
| 1158 | if (inode1) { |
| 1159 | WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); |
| 1160 | inode_unlock(inode1); |
| 1161 | } |
| 1162 | if (inode2 && inode2 != inode1) { |
| 1163 | WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); |
| 1164 | inode_unlock(inode2); |
| 1165 | } |
| 1166 | } |
| 1167 | EXPORT_SYMBOL(unlock_two_nondirectories); |
| 1168 | |
| 1169 | /** |
| 1170 | * inode_insert5 - obtain an inode from a mounted file system |
| 1171 | * @inode: pre-allocated inode to use for insert to cache |
| 1172 | * @hashval: hash value (usually inode number) to get |
| 1173 | * @test: callback used for comparisons between inodes |
| 1174 | * @set: callback used to initialize a new struct inode |
| 1175 | * @data: opaque data pointer to pass to @test and @set |
| 1176 | * |
| 1177 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 1178 | * and if present it is return it with an increased reference count. This is |
| 1179 | * a variant of iget5_locked() for callers that don't want to fail on memory |
| 1180 | * allocation of inode. |
| 1181 | * |
| 1182 | * If the inode is not in cache, insert the pre-allocated inode to cache and |
| 1183 | * return it locked, hashed, and with the I_NEW flag set. The file system gets |
| 1184 | * to fill it in before unlocking it via unlock_new_inode(). |
| 1185 | * |
| 1186 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
| 1187 | * sleep. |
| 1188 | */ |
| 1189 | struct inode *inode_insert5(struct inode *inode, unsigned long hashval, |
| 1190 | int (*test)(struct inode *, void *), |
| 1191 | int (*set)(struct inode *, void *), void *data) |
| 1192 | { |
| 1193 | struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); |
| 1194 | struct inode *old; |
| 1195 | |
| 1196 | again: |
| 1197 | spin_lock(&inode_hash_lock); |
| 1198 | old = find_inode(inode->i_sb, head, test, data); |
| 1199 | if (unlikely(old)) { |
| 1200 | /* |
| 1201 | * Uhhuh, somebody else created the same inode under us. |
| 1202 | * Use the old inode instead of the preallocated one. |
| 1203 | */ |
| 1204 | spin_unlock(&inode_hash_lock); |
| 1205 | if (IS_ERR(old)) |
| 1206 | return NULL; |
| 1207 | wait_on_inode(old); |
| 1208 | if (unlikely(inode_unhashed(old))) { |
| 1209 | iput(old); |
| 1210 | goto again; |
| 1211 | } |
| 1212 | return old; |
| 1213 | } |
| 1214 | |
| 1215 | if (set && unlikely(set(inode, data))) { |
| 1216 | inode = NULL; |
| 1217 | goto unlock; |
| 1218 | } |
| 1219 | |
| 1220 | /* |
| 1221 | * Return the locked inode with I_NEW set, the |
| 1222 | * caller is responsible for filling in the contents |
| 1223 | */ |
| 1224 | spin_lock(&inode->i_lock); |
| 1225 | inode->i_state |= I_NEW; |
| 1226 | hlist_add_head_rcu(&inode->i_hash, head); |
| 1227 | spin_unlock(&inode->i_lock); |
| 1228 | |
| 1229 | /* |
| 1230 | * Add inode to the sb list if it's not already. It has I_NEW at this |
| 1231 | * point, so it should be safe to test i_sb_list locklessly. |
| 1232 | */ |
| 1233 | if (list_empty(&inode->i_sb_list)) |
| 1234 | inode_sb_list_add(inode); |
| 1235 | unlock: |
| 1236 | spin_unlock(&inode_hash_lock); |
| 1237 | |
| 1238 | return inode; |
| 1239 | } |
| 1240 | EXPORT_SYMBOL(inode_insert5); |
| 1241 | |
| 1242 | /** |
| 1243 | * iget5_locked - obtain an inode from a mounted file system |
| 1244 | * @sb: super block of file system |
| 1245 | * @hashval: hash value (usually inode number) to get |
| 1246 | * @test: callback used for comparisons between inodes |
| 1247 | * @set: callback used to initialize a new struct inode |
| 1248 | * @data: opaque data pointer to pass to @test and @set |
| 1249 | * |
| 1250 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 1251 | * and if present it is return it with an increased reference count. This is |
| 1252 | * a generalized version of iget_locked() for file systems where the inode |
| 1253 | * number is not sufficient for unique identification of an inode. |
| 1254 | * |
| 1255 | * If the inode is not in cache, allocate a new inode and return it locked, |
| 1256 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
| 1257 | * before unlocking it via unlock_new_inode(). |
| 1258 | * |
| 1259 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
| 1260 | * sleep. |
| 1261 | */ |
| 1262 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
| 1263 | int (*test)(struct inode *, void *), |
| 1264 | int (*set)(struct inode *, void *), void *data) |
| 1265 | { |
| 1266 | struct inode *inode = ilookup5(sb, hashval, test, data); |
| 1267 | |
| 1268 | if (!inode) { |
| 1269 | struct inode *new = alloc_inode(sb); |
| 1270 | |
| 1271 | if (new) { |
| 1272 | new->i_state = 0; |
| 1273 | inode = inode_insert5(new, hashval, test, set, data); |
| 1274 | if (unlikely(inode != new)) |
| 1275 | destroy_inode(new); |
| 1276 | } |
| 1277 | } |
| 1278 | return inode; |
| 1279 | } |
| 1280 | EXPORT_SYMBOL(iget5_locked); |
| 1281 | |
| 1282 | /** |
| 1283 | * iget_locked - obtain an inode from a mounted file system |
| 1284 | * @sb: super block of file system |
| 1285 | * @ino: inode number to get |
| 1286 | * |
| 1287 | * Search for the inode specified by @ino in the inode cache and if present |
| 1288 | * return it with an increased reference count. This is for file systems |
| 1289 | * where the inode number is sufficient for unique identification of an inode. |
| 1290 | * |
| 1291 | * If the inode is not in cache, allocate a new inode and return it locked, |
| 1292 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
| 1293 | * before unlocking it via unlock_new_inode(). |
| 1294 | */ |
| 1295 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
| 1296 | { |
| 1297 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1298 | struct inode *inode; |
| 1299 | again: |
| 1300 | spin_lock(&inode_hash_lock); |
| 1301 | inode = find_inode_fast(sb, head, ino); |
| 1302 | spin_unlock(&inode_hash_lock); |
| 1303 | if (inode) { |
| 1304 | if (IS_ERR(inode)) |
| 1305 | return NULL; |
| 1306 | wait_on_inode(inode); |
| 1307 | if (unlikely(inode_unhashed(inode))) { |
| 1308 | iput(inode); |
| 1309 | goto again; |
| 1310 | } |
| 1311 | return inode; |
| 1312 | } |
| 1313 | |
| 1314 | inode = alloc_inode(sb); |
| 1315 | if (inode) { |
| 1316 | struct inode *old; |
| 1317 | |
| 1318 | spin_lock(&inode_hash_lock); |
| 1319 | /* We released the lock, so.. */ |
| 1320 | old = find_inode_fast(sb, head, ino); |
| 1321 | if (!old) { |
| 1322 | inode->i_ino = ino; |
| 1323 | spin_lock(&inode->i_lock); |
| 1324 | inode->i_state = I_NEW; |
| 1325 | hlist_add_head_rcu(&inode->i_hash, head); |
| 1326 | spin_unlock(&inode->i_lock); |
| 1327 | inode_sb_list_add(inode); |
| 1328 | spin_unlock(&inode_hash_lock); |
| 1329 | |
| 1330 | /* Return the locked inode with I_NEW set, the |
| 1331 | * caller is responsible for filling in the contents |
| 1332 | */ |
| 1333 | return inode; |
| 1334 | } |
| 1335 | |
| 1336 | /* |
| 1337 | * Uhhuh, somebody else created the same inode under |
| 1338 | * us. Use the old inode instead of the one we just |
| 1339 | * allocated. |
| 1340 | */ |
| 1341 | spin_unlock(&inode_hash_lock); |
| 1342 | destroy_inode(inode); |
| 1343 | if (IS_ERR(old)) |
| 1344 | return NULL; |
| 1345 | inode = old; |
| 1346 | wait_on_inode(inode); |
| 1347 | if (unlikely(inode_unhashed(inode))) { |
| 1348 | iput(inode); |
| 1349 | goto again; |
| 1350 | } |
| 1351 | } |
| 1352 | return inode; |
| 1353 | } |
| 1354 | EXPORT_SYMBOL(iget_locked); |
| 1355 | |
| 1356 | /* |
| 1357 | * search the inode cache for a matching inode number. |
| 1358 | * If we find one, then the inode number we are trying to |
| 1359 | * allocate is not unique and so we should not use it. |
| 1360 | * |
| 1361 | * Returns 1 if the inode number is unique, 0 if it is not. |
| 1362 | */ |
| 1363 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
| 1364 | { |
| 1365 | struct hlist_head *b = inode_hashtable + hash(sb, ino); |
| 1366 | struct inode *inode; |
| 1367 | |
| 1368 | hlist_for_each_entry_rcu(inode, b, i_hash) { |
| 1369 | if (inode->i_ino == ino && inode->i_sb == sb) |
| 1370 | return 0; |
| 1371 | } |
| 1372 | return 1; |
| 1373 | } |
| 1374 | |
| 1375 | /** |
| 1376 | * iunique - get a unique inode number |
| 1377 | * @sb: superblock |
| 1378 | * @max_reserved: highest reserved inode number |
| 1379 | * |
| 1380 | * Obtain an inode number that is unique on the system for a given |
| 1381 | * superblock. This is used by file systems that have no natural |
| 1382 | * permanent inode numbering system. An inode number is returned that |
| 1383 | * is higher than the reserved limit but unique. |
| 1384 | * |
| 1385 | * BUGS: |
| 1386 | * With a large number of inodes live on the file system this function |
| 1387 | * currently becomes quite slow. |
| 1388 | */ |
| 1389 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
| 1390 | { |
| 1391 | /* |
| 1392 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
| 1393 | * error if st_ino won't fit in target struct field. Use 32bit counter |
| 1394 | * here to attempt to avoid that. |
| 1395 | */ |
| 1396 | static DEFINE_SPINLOCK(iunique_lock); |
| 1397 | static unsigned int counter; |
| 1398 | ino_t res; |
| 1399 | |
| 1400 | rcu_read_lock(); |
| 1401 | spin_lock(&iunique_lock); |
| 1402 | do { |
| 1403 | if (counter <= max_reserved) |
| 1404 | counter = max_reserved + 1; |
| 1405 | res = counter++; |
| 1406 | } while (!test_inode_iunique(sb, res)); |
| 1407 | spin_unlock(&iunique_lock); |
| 1408 | rcu_read_unlock(); |
| 1409 | |
| 1410 | return res; |
| 1411 | } |
| 1412 | EXPORT_SYMBOL(iunique); |
| 1413 | |
| 1414 | struct inode *igrab(struct inode *inode) |
| 1415 | { |
| 1416 | spin_lock(&inode->i_lock); |
| 1417 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
| 1418 | __iget(inode); |
| 1419 | spin_unlock(&inode->i_lock); |
| 1420 | } else { |
| 1421 | spin_unlock(&inode->i_lock); |
| 1422 | /* |
| 1423 | * Handle the case where s_op->clear_inode is not been |
| 1424 | * called yet, and somebody is calling igrab |
| 1425 | * while the inode is getting freed. |
| 1426 | */ |
| 1427 | inode = NULL; |
| 1428 | } |
| 1429 | return inode; |
| 1430 | } |
| 1431 | EXPORT_SYMBOL(igrab); |
| 1432 | |
| 1433 | /** |
| 1434 | * ilookup5_nowait - search for an inode in the inode cache |
| 1435 | * @sb: super block of file system to search |
| 1436 | * @hashval: hash value (usually inode number) to search for |
| 1437 | * @test: callback used for comparisons between inodes |
| 1438 | * @data: opaque data pointer to pass to @test |
| 1439 | * |
| 1440 | * Search for the inode specified by @hashval and @data in the inode cache. |
| 1441 | * If the inode is in the cache, the inode is returned with an incremented |
| 1442 | * reference count. |
| 1443 | * |
| 1444 | * Note: I_NEW is not waited upon so you have to be very careful what you do |
| 1445 | * with the returned inode. You probably should be using ilookup5() instead. |
| 1446 | * |
| 1447 | * Note2: @test is called with the inode_hash_lock held, so can't sleep. |
| 1448 | */ |
| 1449 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
| 1450 | int (*test)(struct inode *, void *), void *data) |
| 1451 | { |
| 1452 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| 1453 | struct inode *inode; |
| 1454 | |
| 1455 | spin_lock(&inode_hash_lock); |
| 1456 | inode = find_inode(sb, head, test, data); |
| 1457 | spin_unlock(&inode_hash_lock); |
| 1458 | |
| 1459 | return IS_ERR(inode) ? NULL : inode; |
| 1460 | } |
| 1461 | EXPORT_SYMBOL(ilookup5_nowait); |
| 1462 | |
| 1463 | /** |
| 1464 | * ilookup5 - search for an inode in the inode cache |
| 1465 | * @sb: super block of file system to search |
| 1466 | * @hashval: hash value (usually inode number) to search for |
| 1467 | * @test: callback used for comparisons between inodes |
| 1468 | * @data: opaque data pointer to pass to @test |
| 1469 | * |
| 1470 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 1471 | * and if the inode is in the cache, return the inode with an incremented |
| 1472 | * reference count. Waits on I_NEW before returning the inode. |
| 1473 | * returned with an incremented reference count. |
| 1474 | * |
| 1475 | * This is a generalized version of ilookup() for file systems where the |
| 1476 | * inode number is not sufficient for unique identification of an inode. |
| 1477 | * |
| 1478 | * Note: @test is called with the inode_hash_lock held, so can't sleep. |
| 1479 | */ |
| 1480 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
| 1481 | int (*test)(struct inode *, void *), void *data) |
| 1482 | { |
| 1483 | struct inode *inode; |
| 1484 | again: |
| 1485 | inode = ilookup5_nowait(sb, hashval, test, data); |
| 1486 | if (inode) { |
| 1487 | wait_on_inode(inode); |
| 1488 | if (unlikely(inode_unhashed(inode))) { |
| 1489 | iput(inode); |
| 1490 | goto again; |
| 1491 | } |
| 1492 | } |
| 1493 | return inode; |
| 1494 | } |
| 1495 | EXPORT_SYMBOL(ilookup5); |
| 1496 | |
| 1497 | /** |
| 1498 | * ilookup - search for an inode in the inode cache |
| 1499 | * @sb: super block of file system to search |
| 1500 | * @ino: inode number to search for |
| 1501 | * |
| 1502 | * Search for the inode @ino in the inode cache, and if the inode is in the |
| 1503 | * cache, the inode is returned with an incremented reference count. |
| 1504 | */ |
| 1505 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
| 1506 | { |
| 1507 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1508 | struct inode *inode; |
| 1509 | again: |
| 1510 | spin_lock(&inode_hash_lock); |
| 1511 | inode = find_inode_fast(sb, head, ino); |
| 1512 | spin_unlock(&inode_hash_lock); |
| 1513 | |
| 1514 | if (inode) { |
| 1515 | if (IS_ERR(inode)) |
| 1516 | return NULL; |
| 1517 | wait_on_inode(inode); |
| 1518 | if (unlikely(inode_unhashed(inode))) { |
| 1519 | iput(inode); |
| 1520 | goto again; |
| 1521 | } |
| 1522 | } |
| 1523 | return inode; |
| 1524 | } |
| 1525 | EXPORT_SYMBOL(ilookup); |
| 1526 | |
| 1527 | /** |
| 1528 | * find_inode_nowait - find an inode in the inode cache |
| 1529 | * @sb: super block of file system to search |
| 1530 | * @hashval: hash value (usually inode number) to search for |
| 1531 | * @match: callback used for comparisons between inodes |
| 1532 | * @data: opaque data pointer to pass to @match |
| 1533 | * |
| 1534 | * Search for the inode specified by @hashval and @data in the inode |
| 1535 | * cache, where the helper function @match will return 0 if the inode |
| 1536 | * does not match, 1 if the inode does match, and -1 if the search |
| 1537 | * should be stopped. The @match function must be responsible for |
| 1538 | * taking the i_lock spin_lock and checking i_state for an inode being |
| 1539 | * freed or being initialized, and incrementing the reference count |
| 1540 | * before returning 1. It also must not sleep, since it is called with |
| 1541 | * the inode_hash_lock spinlock held. |
| 1542 | * |
| 1543 | * This is a even more generalized version of ilookup5() when the |
| 1544 | * function must never block --- find_inode() can block in |
| 1545 | * __wait_on_freeing_inode() --- or when the caller can not increment |
| 1546 | * the reference count because the resulting iput() might cause an |
| 1547 | * inode eviction. The tradeoff is that the @match funtion must be |
| 1548 | * very carefully implemented. |
| 1549 | */ |
| 1550 | struct inode *find_inode_nowait(struct super_block *sb, |
| 1551 | unsigned long hashval, |
| 1552 | int (*match)(struct inode *, unsigned long, |
| 1553 | void *), |
| 1554 | void *data) |
| 1555 | { |
| 1556 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| 1557 | struct inode *inode, *ret_inode = NULL; |
| 1558 | int mval; |
| 1559 | |
| 1560 | spin_lock(&inode_hash_lock); |
| 1561 | hlist_for_each_entry(inode, head, i_hash) { |
| 1562 | if (inode->i_sb != sb) |
| 1563 | continue; |
| 1564 | mval = match(inode, hashval, data); |
| 1565 | if (mval == 0) |
| 1566 | continue; |
| 1567 | if (mval == 1) |
| 1568 | ret_inode = inode; |
| 1569 | goto out; |
| 1570 | } |
| 1571 | out: |
| 1572 | spin_unlock(&inode_hash_lock); |
| 1573 | return ret_inode; |
| 1574 | } |
| 1575 | EXPORT_SYMBOL(find_inode_nowait); |
| 1576 | |
| 1577 | /** |
| 1578 | * find_inode_rcu - find an inode in the inode cache |
| 1579 | * @sb: Super block of file system to search |
| 1580 | * @hashval: Key to hash |
| 1581 | * @test: Function to test match on an inode |
| 1582 | * @data: Data for test function |
| 1583 | * |
| 1584 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 1585 | * where the helper function @test will return 0 if the inode does not match |
| 1586 | * and 1 if it does. The @test function must be responsible for taking the |
| 1587 | * i_lock spin_lock and checking i_state for an inode being freed or being |
| 1588 | * initialized. |
| 1589 | * |
| 1590 | * If successful, this will return the inode for which the @test function |
| 1591 | * returned 1 and NULL otherwise. |
| 1592 | * |
| 1593 | * The @test function is not permitted to take a ref on any inode presented. |
| 1594 | * It is also not permitted to sleep. |
| 1595 | * |
| 1596 | * The caller must hold the RCU read lock. |
| 1597 | */ |
| 1598 | struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval, |
| 1599 | int (*test)(struct inode *, void *), void *data) |
| 1600 | { |
| 1601 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
| 1602 | struct inode *inode; |
| 1603 | |
| 1604 | RCU_LOCKDEP_WARN(!rcu_read_lock_held(), |
| 1605 | "suspicious find_inode_rcu() usage"); |
| 1606 | |
| 1607 | hlist_for_each_entry_rcu(inode, head, i_hash) { |
| 1608 | if (inode->i_sb == sb && |
| 1609 | !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)) && |
| 1610 | test(inode, data)) |
| 1611 | return inode; |
| 1612 | } |
| 1613 | return NULL; |
| 1614 | } |
| 1615 | EXPORT_SYMBOL(find_inode_rcu); |
| 1616 | |
| 1617 | /** |
| 1618 | * find_inode_by_ino_rcu - Find an inode in the inode cache |
| 1619 | * @sb: Super block of file system to search |
| 1620 | * @ino: The inode number to match |
| 1621 | * |
| 1622 | * Search for the inode specified by @hashval and @data in the inode cache, |
| 1623 | * where the helper function @test will return 0 if the inode does not match |
| 1624 | * and 1 if it does. The @test function must be responsible for taking the |
| 1625 | * i_lock spin_lock and checking i_state for an inode being freed or being |
| 1626 | * initialized. |
| 1627 | * |
| 1628 | * If successful, this will return the inode for which the @test function |
| 1629 | * returned 1 and NULL otherwise. |
| 1630 | * |
| 1631 | * The @test function is not permitted to take a ref on any inode presented. |
| 1632 | * It is also not permitted to sleep. |
| 1633 | * |
| 1634 | * The caller must hold the RCU read lock. |
| 1635 | */ |
| 1636 | struct inode *find_inode_by_ino_rcu(struct super_block *sb, |
| 1637 | unsigned long ino) |
| 1638 | { |
| 1639 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1640 | struct inode *inode; |
| 1641 | |
| 1642 | RCU_LOCKDEP_WARN(!rcu_read_lock_held(), |
| 1643 | "suspicious find_inode_by_ino_rcu() usage"); |
| 1644 | |
| 1645 | hlist_for_each_entry_rcu(inode, head, i_hash) { |
| 1646 | if (inode->i_ino == ino && |
| 1647 | inode->i_sb == sb && |
| 1648 | !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE))) |
| 1649 | return inode; |
| 1650 | } |
| 1651 | return NULL; |
| 1652 | } |
| 1653 | EXPORT_SYMBOL(find_inode_by_ino_rcu); |
| 1654 | |
| 1655 | int insert_inode_locked(struct inode *inode) |
| 1656 | { |
| 1657 | struct super_block *sb = inode->i_sb; |
| 1658 | ino_t ino = inode->i_ino; |
| 1659 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
| 1660 | |
| 1661 | while (1) { |
| 1662 | struct inode *old = NULL; |
| 1663 | spin_lock(&inode_hash_lock); |
| 1664 | hlist_for_each_entry(old, head, i_hash) { |
| 1665 | if (old->i_ino != ino) |
| 1666 | continue; |
| 1667 | if (old->i_sb != sb) |
| 1668 | continue; |
| 1669 | spin_lock(&old->i_lock); |
| 1670 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
| 1671 | spin_unlock(&old->i_lock); |
| 1672 | continue; |
| 1673 | } |
| 1674 | break; |
| 1675 | } |
| 1676 | if (likely(!old)) { |
| 1677 | spin_lock(&inode->i_lock); |
| 1678 | inode->i_state |= I_NEW | I_CREATING; |
| 1679 | hlist_add_head_rcu(&inode->i_hash, head); |
| 1680 | spin_unlock(&inode->i_lock); |
| 1681 | spin_unlock(&inode_hash_lock); |
| 1682 | return 0; |
| 1683 | } |
| 1684 | if (unlikely(old->i_state & I_CREATING)) { |
| 1685 | spin_unlock(&old->i_lock); |
| 1686 | spin_unlock(&inode_hash_lock); |
| 1687 | return -EBUSY; |
| 1688 | } |
| 1689 | __iget(old); |
| 1690 | spin_unlock(&old->i_lock); |
| 1691 | spin_unlock(&inode_hash_lock); |
| 1692 | wait_on_inode(old); |
| 1693 | if (unlikely(!inode_unhashed(old))) { |
| 1694 | iput(old); |
| 1695 | return -EBUSY; |
| 1696 | } |
| 1697 | iput(old); |
| 1698 | } |
| 1699 | } |
| 1700 | EXPORT_SYMBOL(insert_inode_locked); |
| 1701 | |
| 1702 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
| 1703 | int (*test)(struct inode *, void *), void *data) |
| 1704 | { |
| 1705 | struct inode *old; |
| 1706 | |
| 1707 | inode->i_state |= I_CREATING; |
| 1708 | old = inode_insert5(inode, hashval, test, NULL, data); |
| 1709 | |
| 1710 | if (old != inode) { |
| 1711 | iput(old); |
| 1712 | return -EBUSY; |
| 1713 | } |
| 1714 | return 0; |
| 1715 | } |
| 1716 | EXPORT_SYMBOL(insert_inode_locked4); |
| 1717 | |
| 1718 | |
| 1719 | int generic_delete_inode(struct inode *inode) |
| 1720 | { |
| 1721 | return 1; |
| 1722 | } |
| 1723 | EXPORT_SYMBOL(generic_delete_inode); |
| 1724 | |
| 1725 | /* |
| 1726 | * Called when we're dropping the last reference |
| 1727 | * to an inode. |
| 1728 | * |
| 1729 | * Call the FS "drop_inode()" function, defaulting to |
| 1730 | * the legacy UNIX filesystem behaviour. If it tells |
| 1731 | * us to evict inode, do so. Otherwise, retain inode |
| 1732 | * in cache if fs is alive, sync and evict if fs is |
| 1733 | * shutting down. |
| 1734 | */ |
| 1735 | static void iput_final(struct inode *inode) |
| 1736 | { |
| 1737 | struct super_block *sb = inode->i_sb; |
| 1738 | const struct super_operations *op = inode->i_sb->s_op; |
| 1739 | unsigned long state; |
| 1740 | int drop; |
| 1741 | |
| 1742 | WARN_ON(inode->i_state & I_NEW); |
| 1743 | |
| 1744 | if (op->drop_inode) |
| 1745 | drop = op->drop_inode(inode); |
| 1746 | else |
| 1747 | drop = generic_drop_inode(inode); |
| 1748 | |
| 1749 | if (!drop && |
| 1750 | !(inode->i_state & I_DONTCACHE) && |
| 1751 | (sb->s_flags & SB_ACTIVE)) { |
| 1752 | __inode_add_lru(inode, true); |
| 1753 | spin_unlock(&inode->i_lock); |
| 1754 | return; |
| 1755 | } |
| 1756 | |
| 1757 | state = inode->i_state; |
| 1758 | if (!drop) { |
| 1759 | WRITE_ONCE(inode->i_state, state | I_WILL_FREE); |
| 1760 | spin_unlock(&inode->i_lock); |
| 1761 | |
| 1762 | write_inode_now(inode, 1); |
| 1763 | |
| 1764 | spin_lock(&inode->i_lock); |
| 1765 | state = inode->i_state; |
| 1766 | WARN_ON(state & I_NEW); |
| 1767 | state &= ~I_WILL_FREE; |
| 1768 | } |
| 1769 | |
| 1770 | WRITE_ONCE(inode->i_state, state | I_FREEING); |
| 1771 | if (!list_empty(&inode->i_lru)) |
| 1772 | inode_lru_list_del(inode); |
| 1773 | spin_unlock(&inode->i_lock); |
| 1774 | |
| 1775 | evict(inode); |
| 1776 | } |
| 1777 | |
| 1778 | /** |
| 1779 | * iput - put an inode |
| 1780 | * @inode: inode to put |
| 1781 | * |
| 1782 | * Puts an inode, dropping its usage count. If the inode use count hits |
| 1783 | * zero, the inode is then freed and may also be destroyed. |
| 1784 | * |
| 1785 | * Consequently, iput() can sleep. |
| 1786 | */ |
| 1787 | void iput(struct inode *inode) |
| 1788 | { |
| 1789 | if (!inode) |
| 1790 | return; |
| 1791 | BUG_ON(inode->i_state & I_CLEAR); |
| 1792 | retry: |
| 1793 | if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) { |
| 1794 | if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) { |
| 1795 | atomic_inc(&inode->i_count); |
| 1796 | spin_unlock(&inode->i_lock); |
| 1797 | trace_writeback_lazytime_iput(inode); |
| 1798 | mark_inode_dirty_sync(inode); |
| 1799 | goto retry; |
| 1800 | } |
| 1801 | iput_final(inode); |
| 1802 | } |
| 1803 | } |
| 1804 | EXPORT_SYMBOL(iput); |
| 1805 | |
| 1806 | #ifdef CONFIG_BLOCK |
| 1807 | /** |
| 1808 | * bmap - find a block number in a file |
| 1809 | * @inode: inode owning the block number being requested |
| 1810 | * @block: pointer containing the block to find |
| 1811 | * |
| 1812 | * Replaces the value in ``*block`` with the block number on the device holding |
| 1813 | * corresponding to the requested block number in the file. |
| 1814 | * That is, asked for block 4 of inode 1 the function will replace the |
| 1815 | * 4 in ``*block``, with disk block relative to the disk start that holds that |
| 1816 | * block of the file. |
| 1817 | * |
| 1818 | * Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a |
| 1819 | * hole, returns 0 and ``*block`` is also set to 0. |
| 1820 | */ |
| 1821 | int bmap(struct inode *inode, sector_t *block) |
| 1822 | { |
| 1823 | if (!inode->i_mapping->a_ops->bmap) |
| 1824 | return -EINVAL; |
| 1825 | |
| 1826 | *block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block); |
| 1827 | return 0; |
| 1828 | } |
| 1829 | EXPORT_SYMBOL(bmap); |
| 1830 | #endif |
| 1831 | |
| 1832 | /* |
| 1833 | * With relative atime, only update atime if the previous atime is |
| 1834 | * earlier than or equal to either the ctime or mtime, |
| 1835 | * or if at least a day has passed since the last atime update. |
| 1836 | */ |
| 1837 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
| 1838 | struct timespec64 now) |
| 1839 | { |
| 1840 | struct timespec64 atime, mtime, ctime; |
| 1841 | |
| 1842 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
| 1843 | return 1; |
| 1844 | /* |
| 1845 | * Is mtime younger than or equal to atime? If yes, update atime: |
| 1846 | */ |
| 1847 | atime = inode_get_atime(inode); |
| 1848 | mtime = inode_get_mtime(inode); |
| 1849 | if (timespec64_compare(&mtime, &atime) >= 0) |
| 1850 | return 1; |
| 1851 | /* |
| 1852 | * Is ctime younger than or equal to atime? If yes, update atime: |
| 1853 | */ |
| 1854 | ctime = inode_get_ctime(inode); |
| 1855 | if (timespec64_compare(&ctime, &atime) >= 0) |
| 1856 | return 1; |
| 1857 | |
| 1858 | /* |
| 1859 | * Is the previous atime value older than a day? If yes, |
| 1860 | * update atime: |
| 1861 | */ |
| 1862 | if ((long)(now.tv_sec - atime.tv_sec) >= 24*60*60) |
| 1863 | return 1; |
| 1864 | /* |
| 1865 | * Good, we can skip the atime update: |
| 1866 | */ |
| 1867 | return 0; |
| 1868 | } |
| 1869 | |
| 1870 | /** |
| 1871 | * inode_update_timestamps - update the timestamps on the inode |
| 1872 | * @inode: inode to be updated |
| 1873 | * @flags: S_* flags that needed to be updated |
| 1874 | * |
| 1875 | * The update_time function is called when an inode's timestamps need to be |
| 1876 | * updated for a read or write operation. This function handles updating the |
| 1877 | * actual timestamps. It's up to the caller to ensure that the inode is marked |
| 1878 | * dirty appropriately. |
| 1879 | * |
| 1880 | * In the case where any of S_MTIME, S_CTIME, or S_VERSION need to be updated, |
| 1881 | * attempt to update all three of them. S_ATIME updates can be handled |
| 1882 | * independently of the rest. |
| 1883 | * |
| 1884 | * Returns a set of S_* flags indicating which values changed. |
| 1885 | */ |
| 1886 | int inode_update_timestamps(struct inode *inode, int flags) |
| 1887 | { |
| 1888 | int updated = 0; |
| 1889 | struct timespec64 now; |
| 1890 | |
| 1891 | if (flags & (S_MTIME|S_CTIME|S_VERSION)) { |
| 1892 | struct timespec64 ctime = inode_get_ctime(inode); |
| 1893 | struct timespec64 mtime = inode_get_mtime(inode); |
| 1894 | |
| 1895 | now = inode_set_ctime_current(inode); |
| 1896 | if (!timespec64_equal(&now, &ctime)) |
| 1897 | updated |= S_CTIME; |
| 1898 | if (!timespec64_equal(&now, &mtime)) { |
| 1899 | inode_set_mtime_to_ts(inode, now); |
| 1900 | updated |= S_MTIME; |
| 1901 | } |
| 1902 | if (IS_I_VERSION(inode) && inode_maybe_inc_iversion(inode, updated)) |
| 1903 | updated |= S_VERSION; |
| 1904 | } else { |
| 1905 | now = current_time(inode); |
| 1906 | } |
| 1907 | |
| 1908 | if (flags & S_ATIME) { |
| 1909 | struct timespec64 atime = inode_get_atime(inode); |
| 1910 | |
| 1911 | if (!timespec64_equal(&now, &atime)) { |
| 1912 | inode_set_atime_to_ts(inode, now); |
| 1913 | updated |= S_ATIME; |
| 1914 | } |
| 1915 | } |
| 1916 | return updated; |
| 1917 | } |
| 1918 | EXPORT_SYMBOL(inode_update_timestamps); |
| 1919 | |
| 1920 | /** |
| 1921 | * generic_update_time - update the timestamps on the inode |
| 1922 | * @inode: inode to be updated |
| 1923 | * @flags: S_* flags that needed to be updated |
| 1924 | * |
| 1925 | * The update_time function is called when an inode's timestamps need to be |
| 1926 | * updated for a read or write operation. In the case where any of S_MTIME, S_CTIME, |
| 1927 | * or S_VERSION need to be updated we attempt to update all three of them. S_ATIME |
| 1928 | * updates can be handled done independently of the rest. |
| 1929 | * |
| 1930 | * Returns a S_* mask indicating which fields were updated. |
| 1931 | */ |
| 1932 | int generic_update_time(struct inode *inode, int flags) |
| 1933 | { |
| 1934 | int updated = inode_update_timestamps(inode, flags); |
| 1935 | int dirty_flags = 0; |
| 1936 | |
| 1937 | if (updated & (S_ATIME|S_MTIME|S_CTIME)) |
| 1938 | dirty_flags = inode->i_sb->s_flags & SB_LAZYTIME ? I_DIRTY_TIME : I_DIRTY_SYNC; |
| 1939 | if (updated & S_VERSION) |
| 1940 | dirty_flags |= I_DIRTY_SYNC; |
| 1941 | __mark_inode_dirty(inode, dirty_flags); |
| 1942 | return updated; |
| 1943 | } |
| 1944 | EXPORT_SYMBOL(generic_update_time); |
| 1945 | |
| 1946 | /* |
| 1947 | * This does the actual work of updating an inodes time or version. Must have |
| 1948 | * had called mnt_want_write() before calling this. |
| 1949 | */ |
| 1950 | int inode_update_time(struct inode *inode, int flags) |
| 1951 | { |
| 1952 | if (inode->i_op->update_time) |
| 1953 | return inode->i_op->update_time(inode, flags); |
| 1954 | generic_update_time(inode, flags); |
| 1955 | return 0; |
| 1956 | } |
| 1957 | EXPORT_SYMBOL(inode_update_time); |
| 1958 | |
| 1959 | /** |
| 1960 | * atime_needs_update - update the access time |
| 1961 | * @path: the &struct path to update |
| 1962 | * @inode: inode to update |
| 1963 | * |
| 1964 | * Update the accessed time on an inode and mark it for writeback. |
| 1965 | * This function automatically handles read only file systems and media, |
| 1966 | * as well as the "noatime" flag and inode specific "noatime" markers. |
| 1967 | */ |
| 1968 | bool atime_needs_update(const struct path *path, struct inode *inode) |
| 1969 | { |
| 1970 | struct vfsmount *mnt = path->mnt; |
| 1971 | struct timespec64 now, atime; |
| 1972 | |
| 1973 | if (inode->i_flags & S_NOATIME) |
| 1974 | return false; |
| 1975 | |
| 1976 | /* Atime updates will likely cause i_uid and i_gid to be written |
| 1977 | * back improprely if their true value is unknown to the vfs. |
| 1978 | */ |
| 1979 | if (HAS_UNMAPPED_ID(mnt_idmap(mnt), inode)) |
| 1980 | return false; |
| 1981 | |
| 1982 | if (IS_NOATIME(inode)) |
| 1983 | return false; |
| 1984 | if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode)) |
| 1985 | return false; |
| 1986 | |
| 1987 | if (mnt->mnt_flags & MNT_NOATIME) |
| 1988 | return false; |
| 1989 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
| 1990 | return false; |
| 1991 | |
| 1992 | now = current_time(inode); |
| 1993 | |
| 1994 | if (!relatime_need_update(mnt, inode, now)) |
| 1995 | return false; |
| 1996 | |
| 1997 | atime = inode_get_atime(inode); |
| 1998 | if (timespec64_equal(&atime, &now)) |
| 1999 | return false; |
| 2000 | |
| 2001 | return true; |
| 2002 | } |
| 2003 | |
| 2004 | void touch_atime(const struct path *path) |
| 2005 | { |
| 2006 | struct vfsmount *mnt = path->mnt; |
| 2007 | struct inode *inode = d_inode(path->dentry); |
| 2008 | |
| 2009 | if (!atime_needs_update(path, inode)) |
| 2010 | return; |
| 2011 | |
| 2012 | if (!sb_start_write_trylock(inode->i_sb)) |
| 2013 | return; |
| 2014 | |
| 2015 | if (mnt_get_write_access(mnt) != 0) |
| 2016 | goto skip_update; |
| 2017 | /* |
| 2018 | * File systems can error out when updating inodes if they need to |
| 2019 | * allocate new space to modify an inode (such is the case for |
| 2020 | * Btrfs), but since we touch atime while walking down the path we |
| 2021 | * really don't care if we failed to update the atime of the file, |
| 2022 | * so just ignore the return value. |
| 2023 | * We may also fail on filesystems that have the ability to make parts |
| 2024 | * of the fs read only, e.g. subvolumes in Btrfs. |
| 2025 | */ |
| 2026 | inode_update_time(inode, S_ATIME); |
| 2027 | mnt_put_write_access(mnt); |
| 2028 | skip_update: |
| 2029 | sb_end_write(inode->i_sb); |
| 2030 | } |
| 2031 | EXPORT_SYMBOL(touch_atime); |
| 2032 | |
| 2033 | /* |
| 2034 | * Return mask of changes for notify_change() that need to be done as a |
| 2035 | * response to write or truncate. Return 0 if nothing has to be changed. |
| 2036 | * Negative value on error (change should be denied). |
| 2037 | */ |
| 2038 | int dentry_needs_remove_privs(struct mnt_idmap *idmap, |
| 2039 | struct dentry *dentry) |
| 2040 | { |
| 2041 | struct inode *inode = d_inode(dentry); |
| 2042 | int mask = 0; |
| 2043 | int ret; |
| 2044 | |
| 2045 | if (IS_NOSEC(inode)) |
| 2046 | return 0; |
| 2047 | |
| 2048 | mask = setattr_should_drop_suidgid(idmap, inode); |
| 2049 | ret = security_inode_need_killpriv(dentry); |
| 2050 | if (ret < 0) |
| 2051 | return ret; |
| 2052 | if (ret) |
| 2053 | mask |= ATTR_KILL_PRIV; |
| 2054 | return mask; |
| 2055 | } |
| 2056 | |
| 2057 | static int __remove_privs(struct mnt_idmap *idmap, |
| 2058 | struct dentry *dentry, int kill) |
| 2059 | { |
| 2060 | struct iattr newattrs; |
| 2061 | |
| 2062 | newattrs.ia_valid = ATTR_FORCE | kill; |
| 2063 | /* |
| 2064 | * Note we call this on write, so notify_change will not |
| 2065 | * encounter any conflicting delegations: |
| 2066 | */ |
| 2067 | return notify_change(idmap, dentry, &newattrs, NULL); |
| 2068 | } |
| 2069 | |
| 2070 | static int __file_remove_privs(struct file *file, unsigned int flags) |
| 2071 | { |
| 2072 | struct dentry *dentry = file_dentry(file); |
| 2073 | struct inode *inode = file_inode(file); |
| 2074 | int error = 0; |
| 2075 | int kill; |
| 2076 | |
| 2077 | if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) |
| 2078 | return 0; |
| 2079 | |
| 2080 | kill = dentry_needs_remove_privs(file_mnt_idmap(file), dentry); |
| 2081 | if (kill < 0) |
| 2082 | return kill; |
| 2083 | |
| 2084 | if (kill) { |
| 2085 | if (flags & IOCB_NOWAIT) |
| 2086 | return -EAGAIN; |
| 2087 | |
| 2088 | error = __remove_privs(file_mnt_idmap(file), dentry, kill); |
| 2089 | } |
| 2090 | |
| 2091 | if (!error) |
| 2092 | inode_has_no_xattr(inode); |
| 2093 | return error; |
| 2094 | } |
| 2095 | |
| 2096 | /** |
| 2097 | * file_remove_privs - remove special file privileges (suid, capabilities) |
| 2098 | * @file: file to remove privileges from |
| 2099 | * |
| 2100 | * When file is modified by a write or truncation ensure that special |
| 2101 | * file privileges are removed. |
| 2102 | * |
| 2103 | * Return: 0 on success, negative errno on failure. |
| 2104 | */ |
| 2105 | int file_remove_privs(struct file *file) |
| 2106 | { |
| 2107 | return __file_remove_privs(file, 0); |
| 2108 | } |
| 2109 | EXPORT_SYMBOL(file_remove_privs); |
| 2110 | |
| 2111 | static int inode_needs_update_time(struct inode *inode) |
| 2112 | { |
| 2113 | int sync_it = 0; |
| 2114 | struct timespec64 now = current_time(inode); |
| 2115 | struct timespec64 ts; |
| 2116 | |
| 2117 | /* First try to exhaust all avenues to not sync */ |
| 2118 | if (IS_NOCMTIME(inode)) |
| 2119 | return 0; |
| 2120 | |
| 2121 | ts = inode_get_mtime(inode); |
| 2122 | if (!timespec64_equal(&ts, &now)) |
| 2123 | sync_it = S_MTIME; |
| 2124 | |
| 2125 | ts = inode_get_ctime(inode); |
| 2126 | if (!timespec64_equal(&ts, &now)) |
| 2127 | sync_it |= S_CTIME; |
| 2128 | |
| 2129 | if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode)) |
| 2130 | sync_it |= S_VERSION; |
| 2131 | |
| 2132 | return sync_it; |
| 2133 | } |
| 2134 | |
| 2135 | static int __file_update_time(struct file *file, int sync_mode) |
| 2136 | { |
| 2137 | int ret = 0; |
| 2138 | struct inode *inode = file_inode(file); |
| 2139 | |
| 2140 | /* try to update time settings */ |
| 2141 | if (!mnt_get_write_access_file(file)) { |
| 2142 | ret = inode_update_time(inode, sync_mode); |
| 2143 | mnt_put_write_access_file(file); |
| 2144 | } |
| 2145 | |
| 2146 | return ret; |
| 2147 | } |
| 2148 | |
| 2149 | /** |
| 2150 | * file_update_time - update mtime and ctime time |
| 2151 | * @file: file accessed |
| 2152 | * |
| 2153 | * Update the mtime and ctime members of an inode and mark the inode for |
| 2154 | * writeback. Note that this function is meant exclusively for usage in |
| 2155 | * the file write path of filesystems, and filesystems may choose to |
| 2156 | * explicitly ignore updates via this function with the _NOCMTIME inode |
| 2157 | * flag, e.g. for network filesystem where these imestamps are handled |
| 2158 | * by the server. This can return an error for file systems who need to |
| 2159 | * allocate space in order to update an inode. |
| 2160 | * |
| 2161 | * Return: 0 on success, negative errno on failure. |
| 2162 | */ |
| 2163 | int file_update_time(struct file *file) |
| 2164 | { |
| 2165 | int ret; |
| 2166 | struct inode *inode = file_inode(file); |
| 2167 | |
| 2168 | ret = inode_needs_update_time(inode); |
| 2169 | if (ret <= 0) |
| 2170 | return ret; |
| 2171 | |
| 2172 | return __file_update_time(file, ret); |
| 2173 | } |
| 2174 | EXPORT_SYMBOL(file_update_time); |
| 2175 | |
| 2176 | /** |
| 2177 | * file_modified_flags - handle mandated vfs changes when modifying a file |
| 2178 | * @file: file that was modified |
| 2179 | * @flags: kiocb flags |
| 2180 | * |
| 2181 | * When file has been modified ensure that special |
| 2182 | * file privileges are removed and time settings are updated. |
| 2183 | * |
| 2184 | * If IOCB_NOWAIT is set, special file privileges will not be removed and |
| 2185 | * time settings will not be updated. It will return -EAGAIN. |
| 2186 | * |
| 2187 | * Context: Caller must hold the file's inode lock. |
| 2188 | * |
| 2189 | * Return: 0 on success, negative errno on failure. |
| 2190 | */ |
| 2191 | static int file_modified_flags(struct file *file, int flags) |
| 2192 | { |
| 2193 | int ret; |
| 2194 | struct inode *inode = file_inode(file); |
| 2195 | |
| 2196 | /* |
| 2197 | * Clear the security bits if the process is not being run by root. |
| 2198 | * This keeps people from modifying setuid and setgid binaries. |
| 2199 | */ |
| 2200 | ret = __file_remove_privs(file, flags); |
| 2201 | if (ret) |
| 2202 | return ret; |
| 2203 | |
| 2204 | if (unlikely(file->f_mode & FMODE_NOCMTIME)) |
| 2205 | return 0; |
| 2206 | |
| 2207 | ret = inode_needs_update_time(inode); |
| 2208 | if (ret <= 0) |
| 2209 | return ret; |
| 2210 | if (flags & IOCB_NOWAIT) |
| 2211 | return -EAGAIN; |
| 2212 | |
| 2213 | return __file_update_time(file, ret); |
| 2214 | } |
| 2215 | |
| 2216 | /** |
| 2217 | * file_modified - handle mandated vfs changes when modifying a file |
| 2218 | * @file: file that was modified |
| 2219 | * |
| 2220 | * When file has been modified ensure that special |
| 2221 | * file privileges are removed and time settings are updated. |
| 2222 | * |
| 2223 | * Context: Caller must hold the file's inode lock. |
| 2224 | * |
| 2225 | * Return: 0 on success, negative errno on failure. |
| 2226 | */ |
| 2227 | int file_modified(struct file *file) |
| 2228 | { |
| 2229 | return file_modified_flags(file, 0); |
| 2230 | } |
| 2231 | EXPORT_SYMBOL(file_modified); |
| 2232 | |
| 2233 | /** |
| 2234 | * kiocb_modified - handle mandated vfs changes when modifying a file |
| 2235 | * @iocb: iocb that was modified |
| 2236 | * |
| 2237 | * When file has been modified ensure that special |
| 2238 | * file privileges are removed and time settings are updated. |
| 2239 | * |
| 2240 | * Context: Caller must hold the file's inode lock. |
| 2241 | * |
| 2242 | * Return: 0 on success, negative errno on failure. |
| 2243 | */ |
| 2244 | int kiocb_modified(struct kiocb *iocb) |
| 2245 | { |
| 2246 | return file_modified_flags(iocb->ki_filp, iocb->ki_flags); |
| 2247 | } |
| 2248 | EXPORT_SYMBOL_GPL(kiocb_modified); |
| 2249 | |
| 2250 | int inode_needs_sync(struct inode *inode) |
| 2251 | { |
| 2252 | if (IS_SYNC(inode)) |
| 2253 | return 1; |
| 2254 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
| 2255 | return 1; |
| 2256 | return 0; |
| 2257 | } |
| 2258 | EXPORT_SYMBOL(inode_needs_sync); |
| 2259 | |
| 2260 | /* |
| 2261 | * If we try to find an inode in the inode hash while it is being |
| 2262 | * deleted, we have to wait until the filesystem completes its |
| 2263 | * deletion before reporting that it isn't found. This function waits |
| 2264 | * until the deletion _might_ have completed. Callers are responsible |
| 2265 | * to recheck inode state. |
| 2266 | * |
| 2267 | * It doesn't matter if I_NEW is not set initially, a call to |
| 2268 | * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
| 2269 | * will DTRT. |
| 2270 | */ |
| 2271 | static void __wait_on_freeing_inode(struct inode *inode) |
| 2272 | { |
| 2273 | wait_queue_head_t *wq; |
| 2274 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
| 2275 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
| 2276 | prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE); |
| 2277 | spin_unlock(&inode->i_lock); |
| 2278 | spin_unlock(&inode_hash_lock); |
| 2279 | schedule(); |
| 2280 | finish_wait(wq, &wait.wq_entry); |
| 2281 | spin_lock(&inode_hash_lock); |
| 2282 | } |
| 2283 | |
| 2284 | static __initdata unsigned long ihash_entries; |
| 2285 | static int __init set_ihash_entries(char *str) |
| 2286 | { |
| 2287 | if (!str) |
| 2288 | return 0; |
| 2289 | ihash_entries = simple_strtoul(str, &str, 0); |
| 2290 | return 1; |
| 2291 | } |
| 2292 | __setup("ihash_entries=", set_ihash_entries); |
| 2293 | |
| 2294 | /* |
| 2295 | * Initialize the waitqueues and inode hash table. |
| 2296 | */ |
| 2297 | void __init inode_init_early(void) |
| 2298 | { |
| 2299 | /* If hashes are distributed across NUMA nodes, defer |
| 2300 | * hash allocation until vmalloc space is available. |
| 2301 | */ |
| 2302 | if (hashdist) |
| 2303 | return; |
| 2304 | |
| 2305 | inode_hashtable = |
| 2306 | alloc_large_system_hash("Inode-cache", |
| 2307 | sizeof(struct hlist_head), |
| 2308 | ihash_entries, |
| 2309 | 14, |
| 2310 | HASH_EARLY | HASH_ZERO, |
| 2311 | &i_hash_shift, |
| 2312 | &i_hash_mask, |
| 2313 | 0, |
| 2314 | 0); |
| 2315 | } |
| 2316 | |
| 2317 | void __init inode_init(void) |
| 2318 | { |
| 2319 | /* inode slab cache */ |
| 2320 | inode_cachep = kmem_cache_create("inode_cache", |
| 2321 | sizeof(struct inode), |
| 2322 | 0, |
| 2323 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
| 2324 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), |
| 2325 | init_once); |
| 2326 | |
| 2327 | /* Hash may have been set up in inode_init_early */ |
| 2328 | if (!hashdist) |
| 2329 | return; |
| 2330 | |
| 2331 | inode_hashtable = |
| 2332 | alloc_large_system_hash("Inode-cache", |
| 2333 | sizeof(struct hlist_head), |
| 2334 | ihash_entries, |
| 2335 | 14, |
| 2336 | HASH_ZERO, |
| 2337 | &i_hash_shift, |
| 2338 | &i_hash_mask, |
| 2339 | 0, |
| 2340 | 0); |
| 2341 | } |
| 2342 | |
| 2343 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
| 2344 | { |
| 2345 | inode->i_mode = mode; |
| 2346 | if (S_ISCHR(mode)) { |
| 2347 | inode->i_fop = &def_chr_fops; |
| 2348 | inode->i_rdev = rdev; |
| 2349 | } else if (S_ISBLK(mode)) { |
| 2350 | if (IS_ENABLED(CONFIG_BLOCK)) |
| 2351 | inode->i_fop = &def_blk_fops; |
| 2352 | inode->i_rdev = rdev; |
| 2353 | } else if (S_ISFIFO(mode)) |
| 2354 | inode->i_fop = &pipefifo_fops; |
| 2355 | else if (S_ISSOCK(mode)) |
| 2356 | ; /* leave it no_open_fops */ |
| 2357 | else |
| 2358 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
| 2359 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
| 2360 | inode->i_ino); |
| 2361 | } |
| 2362 | EXPORT_SYMBOL(init_special_inode); |
| 2363 | |
| 2364 | /** |
| 2365 | * inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
| 2366 | * @idmap: idmap of the mount the inode was created from |
| 2367 | * @inode: New inode |
| 2368 | * @dir: Directory inode |
| 2369 | * @mode: mode of the new inode |
| 2370 | * |
| 2371 | * If the inode has been created through an idmapped mount the idmap of |
| 2372 | * the vfsmount must be passed through @idmap. This function will then take |
| 2373 | * care to map the inode according to @idmap before checking permissions |
| 2374 | * and initializing i_uid and i_gid. On non-idmapped mounts or if permission |
| 2375 | * checking is to be performed on the raw inode simply pass @nop_mnt_idmap. |
| 2376 | */ |
| 2377 | void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode, |
| 2378 | const struct inode *dir, umode_t mode) |
| 2379 | { |
| 2380 | inode_fsuid_set(inode, idmap); |
| 2381 | if (dir && dir->i_mode & S_ISGID) { |
| 2382 | inode->i_gid = dir->i_gid; |
| 2383 | |
| 2384 | /* Directories are special, and always inherit S_ISGID */ |
| 2385 | if (S_ISDIR(mode)) |
| 2386 | mode |= S_ISGID; |
| 2387 | } else |
| 2388 | inode_fsgid_set(inode, idmap); |
| 2389 | inode->i_mode = mode; |
| 2390 | } |
| 2391 | EXPORT_SYMBOL(inode_init_owner); |
| 2392 | |
| 2393 | /** |
| 2394 | * inode_owner_or_capable - check current task permissions to inode |
| 2395 | * @idmap: idmap of the mount the inode was found from |
| 2396 | * @inode: inode being checked |
| 2397 | * |
| 2398 | * Return true if current either has CAP_FOWNER in a namespace with the |
| 2399 | * inode owner uid mapped, or owns the file. |
| 2400 | * |
| 2401 | * If the inode has been found through an idmapped mount the idmap of |
| 2402 | * the vfsmount must be passed through @idmap. This function will then take |
| 2403 | * care to map the inode according to @idmap before checking permissions. |
| 2404 | * On non-idmapped mounts or if permission checking is to be performed on the |
| 2405 | * raw inode simply passs @nop_mnt_idmap. |
| 2406 | */ |
| 2407 | bool inode_owner_or_capable(struct mnt_idmap *idmap, |
| 2408 | const struct inode *inode) |
| 2409 | { |
| 2410 | vfsuid_t vfsuid; |
| 2411 | struct user_namespace *ns; |
| 2412 | |
| 2413 | vfsuid = i_uid_into_vfsuid(idmap, inode); |
| 2414 | if (vfsuid_eq_kuid(vfsuid, current_fsuid())) |
| 2415 | return true; |
| 2416 | |
| 2417 | ns = current_user_ns(); |
| 2418 | if (vfsuid_has_mapping(ns, vfsuid) && ns_capable(ns, CAP_FOWNER)) |
| 2419 | return true; |
| 2420 | return false; |
| 2421 | } |
| 2422 | EXPORT_SYMBOL(inode_owner_or_capable); |
| 2423 | |
| 2424 | /* |
| 2425 | * Direct i/o helper functions |
| 2426 | */ |
| 2427 | static void __inode_dio_wait(struct inode *inode) |
| 2428 | { |
| 2429 | wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP); |
| 2430 | DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); |
| 2431 | |
| 2432 | do { |
| 2433 | prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE); |
| 2434 | if (atomic_read(&inode->i_dio_count)) |
| 2435 | schedule(); |
| 2436 | } while (atomic_read(&inode->i_dio_count)); |
| 2437 | finish_wait(wq, &q.wq_entry); |
| 2438 | } |
| 2439 | |
| 2440 | /** |
| 2441 | * inode_dio_wait - wait for outstanding DIO requests to finish |
| 2442 | * @inode: inode to wait for |
| 2443 | * |
| 2444 | * Waits for all pending direct I/O requests to finish so that we can |
| 2445 | * proceed with a truncate or equivalent operation. |
| 2446 | * |
| 2447 | * Must be called under a lock that serializes taking new references |
| 2448 | * to i_dio_count, usually by inode->i_mutex. |
| 2449 | */ |
| 2450 | void inode_dio_wait(struct inode *inode) |
| 2451 | { |
| 2452 | if (atomic_read(&inode->i_dio_count)) |
| 2453 | __inode_dio_wait(inode); |
| 2454 | } |
| 2455 | EXPORT_SYMBOL(inode_dio_wait); |
| 2456 | |
| 2457 | /* |
| 2458 | * inode_set_flags - atomically set some inode flags |
| 2459 | * |
| 2460 | * Note: the caller should be holding i_mutex, or else be sure that |
| 2461 | * they have exclusive access to the inode structure (i.e., while the |
| 2462 | * inode is being instantiated). The reason for the cmpxchg() loop |
| 2463 | * --- which wouldn't be necessary if all code paths which modify |
| 2464 | * i_flags actually followed this rule, is that there is at least one |
| 2465 | * code path which doesn't today so we use cmpxchg() out of an abundance |
| 2466 | * of caution. |
| 2467 | * |
| 2468 | * In the long run, i_mutex is overkill, and we should probably look |
| 2469 | * at using the i_lock spinlock to protect i_flags, and then make sure |
| 2470 | * it is so documented in include/linux/fs.h and that all code follows |
| 2471 | * the locking convention!! |
| 2472 | */ |
| 2473 | void inode_set_flags(struct inode *inode, unsigned int flags, |
| 2474 | unsigned int mask) |
| 2475 | { |
| 2476 | WARN_ON_ONCE(flags & ~mask); |
| 2477 | set_mask_bits(&inode->i_flags, mask, flags); |
| 2478 | } |
| 2479 | EXPORT_SYMBOL(inode_set_flags); |
| 2480 | |
| 2481 | void inode_nohighmem(struct inode *inode) |
| 2482 | { |
| 2483 | mapping_set_gfp_mask(inode->i_mapping, GFP_USER); |
| 2484 | } |
| 2485 | EXPORT_SYMBOL(inode_nohighmem); |
| 2486 | |
| 2487 | /** |
| 2488 | * timestamp_truncate - Truncate timespec to a granularity |
| 2489 | * @t: Timespec |
| 2490 | * @inode: inode being updated |
| 2491 | * |
| 2492 | * Truncate a timespec to the granularity supported by the fs |
| 2493 | * containing the inode. Always rounds down. gran must |
| 2494 | * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). |
| 2495 | */ |
| 2496 | struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode) |
| 2497 | { |
| 2498 | struct super_block *sb = inode->i_sb; |
| 2499 | unsigned int gran = sb->s_time_gran; |
| 2500 | |
| 2501 | t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max); |
| 2502 | if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min)) |
| 2503 | t.tv_nsec = 0; |
| 2504 | |
| 2505 | /* Avoid division in the common cases 1 ns and 1 s. */ |
| 2506 | if (gran == 1) |
| 2507 | ; /* nothing */ |
| 2508 | else if (gran == NSEC_PER_SEC) |
| 2509 | t.tv_nsec = 0; |
| 2510 | else if (gran > 1 && gran < NSEC_PER_SEC) |
| 2511 | t.tv_nsec -= t.tv_nsec % gran; |
| 2512 | else |
| 2513 | WARN(1, "invalid file time granularity: %u", gran); |
| 2514 | return t; |
| 2515 | } |
| 2516 | EXPORT_SYMBOL(timestamp_truncate); |
| 2517 | |
| 2518 | /** |
| 2519 | * current_time - Return FS time |
| 2520 | * @inode: inode. |
| 2521 | * |
| 2522 | * Return the current time truncated to the time granularity supported by |
| 2523 | * the fs. |
| 2524 | * |
| 2525 | * Note that inode and inode->sb cannot be NULL. |
| 2526 | * Otherwise, the function warns and returns time without truncation. |
| 2527 | */ |
| 2528 | struct timespec64 current_time(struct inode *inode) |
| 2529 | { |
| 2530 | struct timespec64 now; |
| 2531 | |
| 2532 | ktime_get_coarse_real_ts64(&now); |
| 2533 | return timestamp_truncate(now, inode); |
| 2534 | } |
| 2535 | EXPORT_SYMBOL(current_time); |
| 2536 | |
| 2537 | /** |
| 2538 | * inode_set_ctime_current - set the ctime to current_time |
| 2539 | * @inode: inode |
| 2540 | * |
| 2541 | * Set the inode->i_ctime to the current value for the inode. Returns |
| 2542 | * the current value that was assigned to i_ctime. |
| 2543 | */ |
| 2544 | struct timespec64 inode_set_ctime_current(struct inode *inode) |
| 2545 | { |
| 2546 | struct timespec64 now = current_time(inode); |
| 2547 | |
| 2548 | inode_set_ctime(inode, now.tv_sec, now.tv_nsec); |
| 2549 | return now; |
| 2550 | } |
| 2551 | EXPORT_SYMBOL(inode_set_ctime_current); |
| 2552 | |
| 2553 | /** |
| 2554 | * in_group_or_capable - check whether caller is CAP_FSETID privileged |
| 2555 | * @idmap: idmap of the mount @inode was found from |
| 2556 | * @inode: inode to check |
| 2557 | * @vfsgid: the new/current vfsgid of @inode |
| 2558 | * |
| 2559 | * Check wether @vfsgid is in the caller's group list or if the caller is |
| 2560 | * privileged with CAP_FSETID over @inode. This can be used to determine |
| 2561 | * whether the setgid bit can be kept or must be dropped. |
| 2562 | * |
| 2563 | * Return: true if the caller is sufficiently privileged, false if not. |
| 2564 | */ |
| 2565 | bool in_group_or_capable(struct mnt_idmap *idmap, |
| 2566 | const struct inode *inode, vfsgid_t vfsgid) |
| 2567 | { |
| 2568 | if (vfsgid_in_group_p(vfsgid)) |
| 2569 | return true; |
| 2570 | if (capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID)) |
| 2571 | return true; |
| 2572 | return false; |
| 2573 | } |
| 2574 | |
| 2575 | /** |
| 2576 | * mode_strip_sgid - handle the sgid bit for non-directories |
| 2577 | * @idmap: idmap of the mount the inode was created from |
| 2578 | * @dir: parent directory inode |
| 2579 | * @mode: mode of the file to be created in @dir |
| 2580 | * |
| 2581 | * If the @mode of the new file has both the S_ISGID and S_IXGRP bit |
| 2582 | * raised and @dir has the S_ISGID bit raised ensure that the caller is |
| 2583 | * either in the group of the parent directory or they have CAP_FSETID |
| 2584 | * in their user namespace and are privileged over the parent directory. |
| 2585 | * In all other cases, strip the S_ISGID bit from @mode. |
| 2586 | * |
| 2587 | * Return: the new mode to use for the file |
| 2588 | */ |
| 2589 | umode_t mode_strip_sgid(struct mnt_idmap *idmap, |
| 2590 | const struct inode *dir, umode_t mode) |
| 2591 | { |
| 2592 | if ((mode & (S_ISGID | S_IXGRP)) != (S_ISGID | S_IXGRP)) |
| 2593 | return mode; |
| 2594 | if (S_ISDIR(mode) || !dir || !(dir->i_mode & S_ISGID)) |
| 2595 | return mode; |
| 2596 | if (in_group_or_capable(idmap, dir, i_gid_into_vfsgid(idmap, dir))) |
| 2597 | return mode; |
| 2598 | return mode & ~S_ISGID; |
| 2599 | } |
| 2600 | EXPORT_SYMBOL(mode_strip_sgid); |