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