1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Filesystem access notification for Linux 4 * 5 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> 6 */ 7 8 #ifndef __LINUX_FSNOTIFY_BACKEND_H 9 #define __LINUX_FSNOTIFY_BACKEND_H 10 11 #ifdef __KERNEL__ 12 13 #include <linux/idr.h> /* inotify uses this */ 14 #include <linux/fs.h> /* struct inode */ 15 #include <linux/list.h> 16 #include <linux/path.h> /* struct path */ 17 #include <linux/spinlock.h> 18 #include <linux/types.h> 19 #include <linux/atomic.h> 20 #include <linux/user_namespace.h> 21 #include <linux/refcount.h> 22 23 /* 24 * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily 25 * convert between them. dnotify only needs conversion at watch creation 26 * so no perf loss there. fanotify isn't defined yet, so it can use the 27 * wholes if it needs more events. 28 */ 29 #define FS_ACCESS 0x00000001 /* File was accessed */ 30 #define FS_MODIFY 0x00000002 /* File was modified */ 31 #define FS_ATTRIB 0x00000004 /* Metadata changed */ 32 #define FS_CLOSE_WRITE 0x00000008 /* Writtable file was closed */ 33 #define FS_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */ 34 #define FS_OPEN 0x00000020 /* File was opened */ 35 #define FS_MOVED_FROM 0x00000040 /* File was moved from X */ 36 #define FS_MOVED_TO 0x00000080 /* File was moved to Y */ 37 #define FS_CREATE 0x00000100 /* Subfile was created */ 38 #define FS_DELETE 0x00000200 /* Subfile was deleted */ 39 #define FS_DELETE_SELF 0x00000400 /* Self was deleted */ 40 #define FS_MOVE_SELF 0x00000800 /* Self was moved */ 41 #define FS_OPEN_EXEC 0x00001000 /* File was opened for exec */ 42 43 #define FS_UNMOUNT 0x00002000 /* inode on umount fs */ 44 #define FS_Q_OVERFLOW 0x00004000 /* Event queued overflowed */ 45 #define FS_IN_IGNORED 0x00008000 /* last inotify event here */ 46 47 #define FS_OPEN_PERM 0x00010000 /* open event in an permission hook */ 48 #define FS_ACCESS_PERM 0x00020000 /* access event in a permissions hook */ 49 #define FS_OPEN_EXEC_PERM 0x00040000 /* open/exec event in a permission hook */ 50 51 #define FS_EXCL_UNLINK 0x04000000 /* do not send events if object is unlinked */ 52 #define FS_ISDIR 0x40000000 /* event occurred against dir */ 53 #define FS_IN_ONESHOT 0x80000000 /* only send event once */ 54 55 #define FS_DN_RENAME 0x10000000 /* file renamed */ 56 #define FS_DN_MULTISHOT 0x20000000 /* dnotify multishot */ 57 58 /* This inode cares about things that happen to its children. Always set for 59 * dnotify and inotify. */ 60 #define FS_EVENT_ON_CHILD 0x08000000 61 62 #define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO) 63 64 /* 65 * Directory entry modification events - reported only to directory 66 * where entry is modified and not to a watching parent. 67 * The watching parent may get an FS_ATTRIB|FS_EVENT_ON_CHILD event 68 * when a directory entry inside a child subdir changes. 69 */ 70 #define ALL_FSNOTIFY_DIRENT_EVENTS (FS_CREATE | FS_DELETE | FS_MOVE) 71 72 #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \ 73 FS_OPEN_EXEC_PERM) 74 75 /* 76 * This is a list of all events that may get sent to a parent based on fs event 77 * happening to inodes inside that directory. 78 */ 79 #define FS_EVENTS_POSS_ON_CHILD (ALL_FSNOTIFY_PERM_EVENTS | \ 80 FS_ACCESS | FS_MODIFY | FS_ATTRIB | \ 81 FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \ 82 FS_OPEN | FS_OPEN_EXEC) 83 84 /* Events that can be reported to backends */ 85 #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \ 86 FS_EVENTS_POSS_ON_CHILD | \ 87 FS_DELETE_SELF | FS_MOVE_SELF | FS_DN_RENAME | \ 88 FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED) 89 90 /* Extra flags that may be reported with event or control handling of events */ 91 #define ALL_FSNOTIFY_FLAGS (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \ 92 FS_DN_MULTISHOT | FS_EVENT_ON_CHILD) 93 94 #define ALL_FSNOTIFY_BITS (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS) 95 96 struct fsnotify_group; 97 struct fsnotify_event; 98 struct fsnotify_mark; 99 struct fsnotify_event_private_data; 100 struct fsnotify_fname; 101 struct fsnotify_iter_info; 102 103 struct mem_cgroup; 104 105 /* 106 * Each group much define these ops. The fsnotify infrastructure will call 107 * these operations for each relevant group. 108 * 109 * handle_event - main call for a group to handle an fs event 110 * free_group_priv - called when a group refcnt hits 0 to clean up the private union 111 * freeing_mark - called when a mark is being destroyed for some reason. The group 112 * MUST be holding a reference on each mark and that reference must be 113 * dropped in this function. inotify uses this function to send 114 * userspace messages that marks have been removed. 115 */ 116 struct fsnotify_ops { 117 int (*handle_event)(struct fsnotify_group *group, 118 struct inode *inode, 119 u32 mask, const void *data, int data_type, 120 const struct qstr *file_name, u32 cookie, 121 struct fsnotify_iter_info *iter_info); 122 void (*free_group_priv)(struct fsnotify_group *group); 123 void (*freeing_mark)(struct fsnotify_mark *mark, struct fsnotify_group *group); 124 void (*free_event)(struct fsnotify_event *event); 125 /* called on final put+free to free memory */ 126 void (*free_mark)(struct fsnotify_mark *mark); 127 }; 128 129 /* 130 * all of the information about the original object we want to now send to 131 * a group. If you want to carry more info from the accessing task to the 132 * listener this structure is where you need to be adding fields. 133 */ 134 struct fsnotify_event { 135 struct list_head list; 136 /* inode may ONLY be dereferenced during handle_event(). */ 137 struct inode *inode; /* either the inode the event happened to or its parent */ 138 }; 139 140 /* 141 * A group is a "thing" that wants to receive notification about filesystem 142 * events. The mask holds the subset of event types this group cares about. 143 * refcnt on a group is up to the implementor and at any moment if it goes 0 144 * everything will be cleaned up. 145 */ 146 struct fsnotify_group { 147 const struct fsnotify_ops *ops; /* how this group handles things */ 148 149 /* 150 * How the refcnt is used is up to each group. When the refcnt hits 0 151 * fsnotify will clean up all of the resources associated with this group. 152 * As an example, the dnotify group will always have a refcnt=1 and that 153 * will never change. Inotify, on the other hand, has a group per 154 * inotify_init() and the refcnt will hit 0 only when that fd has been 155 * closed. 156 */ 157 refcount_t refcnt; /* things with interest in this group */ 158 159 /* needed to send notification to userspace */ 160 spinlock_t notification_lock; /* protect the notification_list */ 161 struct list_head notification_list; /* list of event_holder this group needs to send to userspace */ 162 wait_queue_head_t notification_waitq; /* read() on the notification file blocks on this waitq */ 163 unsigned int q_len; /* events on the queue */ 164 unsigned int max_events; /* maximum events allowed on the list */ 165 /* 166 * Valid fsnotify group priorities. Events are send in order from highest 167 * priority to lowest priority. We default to the lowest priority. 168 */ 169 #define FS_PRIO_0 0 /* normal notifiers, no permissions */ 170 #define FS_PRIO_1 1 /* fanotify content based access control */ 171 #define FS_PRIO_2 2 /* fanotify pre-content access */ 172 unsigned int priority; 173 bool shutdown; /* group is being shut down, don't queue more events */ 174 175 /* stores all fastpath marks assoc with this group so they can be cleaned on unregister */ 176 struct mutex mark_mutex; /* protect marks_list */ 177 atomic_t num_marks; /* 1 for each mark and 1 for not being 178 * past the point of no return when freeing 179 * a group */ 180 atomic_t user_waits; /* Number of tasks waiting for user 181 * response */ 182 struct list_head marks_list; /* all inode marks for this group */ 183 184 struct fasync_struct *fsn_fa; /* async notification */ 185 186 struct fsnotify_event *overflow_event; /* Event we queue when the 187 * notification list is too 188 * full */ 189 190 struct mem_cgroup *memcg; /* memcg to charge allocations */ 191 192 /* groups can define private fields here or use the void *private */ 193 union { 194 void *private; 195 #ifdef CONFIG_INOTIFY_USER 196 struct inotify_group_private_data { 197 spinlock_t idr_lock; 198 struct idr idr; 199 struct ucounts *ucounts; 200 } inotify_data; 201 #endif 202 #ifdef CONFIG_FANOTIFY 203 struct fanotify_group_private_data { 204 /* allows a group to block waiting for a userspace response */ 205 struct list_head access_list; 206 wait_queue_head_t access_waitq; 207 int flags; /* flags from fanotify_init() */ 208 int f_flags; /* event_f_flags from fanotify_init() */ 209 unsigned int max_marks; 210 struct user_struct *user; 211 } fanotify_data; 212 #endif /* CONFIG_FANOTIFY */ 213 }; 214 }; 215 216 /* when calling fsnotify tell it if the data is a path or inode */ 217 #define FSNOTIFY_EVENT_NONE 0 218 #define FSNOTIFY_EVENT_PATH 1 219 #define FSNOTIFY_EVENT_INODE 2 220 221 enum fsnotify_obj_type { 222 FSNOTIFY_OBJ_TYPE_INODE, 223 FSNOTIFY_OBJ_TYPE_VFSMOUNT, 224 FSNOTIFY_OBJ_TYPE_SB, 225 FSNOTIFY_OBJ_TYPE_COUNT, 226 FSNOTIFY_OBJ_TYPE_DETACHED = FSNOTIFY_OBJ_TYPE_COUNT 227 }; 228 229 #define FSNOTIFY_OBJ_TYPE_INODE_FL (1U << FSNOTIFY_OBJ_TYPE_INODE) 230 #define FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL (1U << FSNOTIFY_OBJ_TYPE_VFSMOUNT) 231 #define FSNOTIFY_OBJ_TYPE_SB_FL (1U << FSNOTIFY_OBJ_TYPE_SB) 232 #define FSNOTIFY_OBJ_ALL_TYPES_MASK ((1U << FSNOTIFY_OBJ_TYPE_COUNT) - 1) 233 234 static inline bool fsnotify_valid_obj_type(unsigned int type) 235 { 236 return (type < FSNOTIFY_OBJ_TYPE_COUNT); 237 } 238 239 struct fsnotify_iter_info { 240 struct fsnotify_mark *marks[FSNOTIFY_OBJ_TYPE_COUNT]; 241 unsigned int report_mask; 242 int srcu_idx; 243 }; 244 245 static inline bool fsnotify_iter_should_report_type( 246 struct fsnotify_iter_info *iter_info, int type) 247 { 248 return (iter_info->report_mask & (1U << type)); 249 } 250 251 static inline void fsnotify_iter_set_report_type( 252 struct fsnotify_iter_info *iter_info, int type) 253 { 254 iter_info->report_mask |= (1U << type); 255 } 256 257 static inline void fsnotify_iter_set_report_type_mark( 258 struct fsnotify_iter_info *iter_info, int type, 259 struct fsnotify_mark *mark) 260 { 261 iter_info->marks[type] = mark; 262 iter_info->report_mask |= (1U << type); 263 } 264 265 #define FSNOTIFY_ITER_FUNCS(name, NAME) \ 266 static inline struct fsnotify_mark *fsnotify_iter_##name##_mark( \ 267 struct fsnotify_iter_info *iter_info) \ 268 { \ 269 return (iter_info->report_mask & FSNOTIFY_OBJ_TYPE_##NAME##_FL) ? \ 270 iter_info->marks[FSNOTIFY_OBJ_TYPE_##NAME] : NULL; \ 271 } 272 273 FSNOTIFY_ITER_FUNCS(inode, INODE) 274 FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT) 275 FSNOTIFY_ITER_FUNCS(sb, SB) 276 277 #define fsnotify_foreach_obj_type(type) \ 278 for (type = 0; type < FSNOTIFY_OBJ_TYPE_COUNT; type++) 279 280 /* 281 * fsnotify_connp_t is what we embed in objects which connector can be attached 282 * to. fsnotify_connp_t * is how we refer from connector back to object. 283 */ 284 struct fsnotify_mark_connector; 285 typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t; 286 287 /* 288 * Inode/vfsmount/sb point to this structure which tracks all marks attached to 289 * the inode/vfsmount/sb. The reference to inode/vfsmount/sb is held by this 290 * structure. We destroy this structure when there are no more marks attached 291 * to it. The structure is protected by fsnotify_mark_srcu. 292 */ 293 struct fsnotify_mark_connector { 294 spinlock_t lock; 295 unsigned short type; /* Type of object [lock] */ 296 #define FSNOTIFY_CONN_FLAG_HAS_FSID 0x01 297 unsigned short flags; /* flags [lock] */ 298 __kernel_fsid_t fsid; /* fsid of filesystem containing object */ 299 union { 300 /* Object pointer [lock] */ 301 fsnotify_connp_t *obj; 302 /* Used listing heads to free after srcu period expires */ 303 struct fsnotify_mark_connector *destroy_next; 304 }; 305 struct hlist_head list; 306 }; 307 308 /* 309 * A mark is simply an object attached to an in core inode which allows an 310 * fsnotify listener to indicate they are either no longer interested in events 311 * of a type matching mask or only interested in those events. 312 * 313 * These are flushed when an inode is evicted from core and may be flushed 314 * when the inode is modified (as seen by fsnotify_access). Some fsnotify 315 * users (such as dnotify) will flush these when the open fd is closed and not 316 * at inode eviction or modification. 317 * 318 * Text in brackets is showing the lock(s) protecting modifications of a 319 * particular entry. obj_lock means either inode->i_lock or 320 * mnt->mnt_root->d_lock depending on the mark type. 321 */ 322 struct fsnotify_mark { 323 /* Mask this mark is for [mark->lock, group->mark_mutex] */ 324 __u32 mask; 325 /* We hold one for presence in g_list. Also one ref for each 'thing' 326 * in kernel that found and may be using this mark. */ 327 refcount_t refcnt; 328 /* Group this mark is for. Set on mark creation, stable until last ref 329 * is dropped */ 330 struct fsnotify_group *group; 331 /* List of marks by group->marks_list. Also reused for queueing 332 * mark into destroy_list when it's waiting for the end of SRCU period 333 * before it can be freed. [group->mark_mutex] */ 334 struct list_head g_list; 335 /* Protects inode / mnt pointers, flags, masks */ 336 spinlock_t lock; 337 /* List of marks for inode / vfsmount [connector->lock, mark ref] */ 338 struct hlist_node obj_list; 339 /* Head of list of marks for an object [mark ref] */ 340 struct fsnotify_mark_connector *connector; 341 /* Events types to ignore [mark->lock, group->mark_mutex] */ 342 __u32 ignored_mask; 343 #define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x01 344 #define FSNOTIFY_MARK_FLAG_ALIVE 0x02 345 #define FSNOTIFY_MARK_FLAG_ATTACHED 0x04 346 unsigned int flags; /* flags [mark->lock] */ 347 }; 348 349 #ifdef CONFIG_FSNOTIFY 350 351 /* called from the vfs helpers */ 352 353 /* main fsnotify call to send events */ 354 extern int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, 355 const struct qstr *name, u32 cookie); 356 extern int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask); 357 extern void __fsnotify_inode_delete(struct inode *inode); 358 extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt); 359 extern void fsnotify_sb_delete(struct super_block *sb); 360 extern u32 fsnotify_get_cookie(void); 361 362 static inline int fsnotify_inode_watches_children(struct inode *inode) 363 { 364 /* FS_EVENT_ON_CHILD is set if the inode may care */ 365 if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD)) 366 return 0; 367 /* this inode might care about child events, does it care about the 368 * specific set of events that can happen on a child? */ 369 return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD; 370 } 371 372 /* 373 * Update the dentry with a flag indicating the interest of its parent to receive 374 * filesystem events when those events happens to this dentry->d_inode. 375 */ 376 static inline void fsnotify_update_flags(struct dentry *dentry) 377 { 378 assert_spin_locked(&dentry->d_lock); 379 380 /* 381 * Serialisation of setting PARENT_WATCHED on the dentries is provided 382 * by d_lock. If inotify_inode_watched changes after we have taken 383 * d_lock, the following __fsnotify_update_child_dentry_flags call will 384 * find our entry, so it will spin until we complete here, and update 385 * us with the new state. 386 */ 387 if (fsnotify_inode_watches_children(dentry->d_parent->d_inode)) 388 dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; 389 else 390 dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; 391 } 392 393 /* called from fsnotify listeners, such as fanotify or dnotify */ 394 395 /* create a new group */ 396 extern struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops); 397 /* get reference to a group */ 398 extern void fsnotify_get_group(struct fsnotify_group *group); 399 /* drop reference on a group from fsnotify_alloc_group */ 400 extern void fsnotify_put_group(struct fsnotify_group *group); 401 /* group destruction begins, stop queuing new events */ 402 extern void fsnotify_group_stop_queueing(struct fsnotify_group *group); 403 /* destroy group */ 404 extern void fsnotify_destroy_group(struct fsnotify_group *group); 405 /* fasync handler function */ 406 extern int fsnotify_fasync(int fd, struct file *file, int on); 407 /* Free event from memory */ 408 extern void fsnotify_destroy_event(struct fsnotify_group *group, 409 struct fsnotify_event *event); 410 /* attach the event to the group notification queue */ 411 extern int fsnotify_add_event(struct fsnotify_group *group, 412 struct fsnotify_event *event, 413 int (*merge)(struct list_head *, 414 struct fsnotify_event *)); 415 /* Queue overflow event to a notification group */ 416 static inline void fsnotify_queue_overflow(struct fsnotify_group *group) 417 { 418 fsnotify_add_event(group, group->overflow_event, NULL); 419 } 420 421 /* true if the group notification queue is empty */ 422 extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group); 423 /* return, but do not dequeue the first event on the notification queue */ 424 extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group); 425 /* return AND dequeue the first event on the notification queue */ 426 extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group); 427 /* Remove event queued in the notification list */ 428 extern void fsnotify_remove_queued_event(struct fsnotify_group *group, 429 struct fsnotify_event *event); 430 431 /* functions used to manipulate the marks attached to inodes */ 432 433 /* Get mask of events for a list of marks */ 434 extern __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn); 435 /* Calculate mask of events for a list of marks */ 436 extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn); 437 extern void fsnotify_init_mark(struct fsnotify_mark *mark, 438 struct fsnotify_group *group); 439 /* Find mark belonging to given group in the list of marks */ 440 extern struct fsnotify_mark *fsnotify_find_mark(fsnotify_connp_t *connp, 441 struct fsnotify_group *group); 442 /* Get cached fsid of filesystem containing object */ 443 extern int fsnotify_get_conn_fsid(const struct fsnotify_mark_connector *conn, 444 __kernel_fsid_t *fsid); 445 /* attach the mark to the object */ 446 extern int fsnotify_add_mark(struct fsnotify_mark *mark, 447 fsnotify_connp_t *connp, unsigned int type, 448 int allow_dups, __kernel_fsid_t *fsid); 449 extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark, 450 fsnotify_connp_t *connp, 451 unsigned int type, int allow_dups, 452 __kernel_fsid_t *fsid); 453 454 /* attach the mark to the inode */ 455 static inline int fsnotify_add_inode_mark(struct fsnotify_mark *mark, 456 struct inode *inode, 457 int allow_dups) 458 { 459 return fsnotify_add_mark(mark, &inode->i_fsnotify_marks, 460 FSNOTIFY_OBJ_TYPE_INODE, allow_dups, NULL); 461 } 462 static inline int fsnotify_add_inode_mark_locked(struct fsnotify_mark *mark, 463 struct inode *inode, 464 int allow_dups) 465 { 466 return fsnotify_add_mark_locked(mark, &inode->i_fsnotify_marks, 467 FSNOTIFY_OBJ_TYPE_INODE, allow_dups, 468 NULL); 469 } 470 471 /* given a group and a mark, flag mark to be freed when all references are dropped */ 472 extern void fsnotify_destroy_mark(struct fsnotify_mark *mark, 473 struct fsnotify_group *group); 474 /* detach mark from inode / mount list, group list, drop inode reference */ 475 extern void fsnotify_detach_mark(struct fsnotify_mark *mark); 476 /* free mark */ 477 extern void fsnotify_free_mark(struct fsnotify_mark *mark); 478 /* Wait until all marks queued for destruction are destroyed */ 479 extern void fsnotify_wait_marks_destroyed(void); 480 /* run all the marks in a group, and clear all of the marks attached to given object type */ 481 extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group, unsigned int type); 482 /* run all the marks in a group, and clear all of the vfsmount marks */ 483 static inline void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group) 484 { 485 fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL); 486 } 487 /* run all the marks in a group, and clear all of the inode marks */ 488 static inline void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) 489 { 490 fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_INODE_FL); 491 } 492 /* run all the marks in a group, and clear all of the sn marks */ 493 static inline void fsnotify_clear_sb_marks_by_group(struct fsnotify_group *group) 494 { 495 fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_SB_FL); 496 } 497 extern void fsnotify_get_mark(struct fsnotify_mark *mark); 498 extern void fsnotify_put_mark(struct fsnotify_mark *mark); 499 extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info); 500 extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info); 501 502 static inline void fsnotify_init_event(struct fsnotify_event *event, 503 struct inode *inode) 504 { 505 INIT_LIST_HEAD(&event->list); 506 event->inode = inode; 507 } 508 509 #else 510 511 static inline int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, 512 const struct qstr *name, u32 cookie) 513 { 514 return 0; 515 } 516 517 static inline int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask) 518 { 519 return 0; 520 } 521 522 static inline void __fsnotify_inode_delete(struct inode *inode) 523 {} 524 525 static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt) 526 {} 527 528 static inline void fsnotify_sb_delete(struct super_block *sb) 529 {} 530 531 static inline void fsnotify_update_flags(struct dentry *dentry) 532 {} 533 534 static inline u32 fsnotify_get_cookie(void) 535 { 536 return 0; 537 } 538 539 static inline void fsnotify_unmount_inodes(struct super_block *sb) 540 {} 541 542 #endif /* CONFIG_FSNOTIFY */ 543 544 #endif /* __KERNEL __ */ 545 546 #endif /* __LINUX_FSNOTIFY_BACKEND_H */ 547