include/linux/fsnotify_backend.h

   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         unsigned long objectid; /* identifier for queue merges */
 137 };
 138
 139 /*
 140  * A group is a "thing" that wants to receive notification about filesystem
 141  * events.  The mask holds the subset of event types this group cares about.
 142  * refcnt on a group is up to the implementor and at any moment if it goes 0
 143  * everything will be cleaned up.
 144  */
 145 struct fsnotify_group {
 146         const struct fsnotify_ops *ops; /* how this group handles things */
 147
 148         /*
 149          * How the refcnt is used is up to each group.  When the refcnt hits 0
 150          * fsnotify will clean up all of the resources associated with this group.
 151          * As an example, the dnotify group will always have a refcnt=1 and that
 152          * will never change.  Inotify, on the other hand, has a group per
 153          * inotify_init() and the refcnt will hit 0 only when that fd has been
 154          * closed.
 155          */
 156         refcount_t refcnt;              /* things with interest in this group */
 157
 158         /* needed to send notification to userspace */
 159         spinlock_t notification_lock;           /* protect the notification_list */
 160         struct list_head notification_list;     /* list of event_holder this group needs to send to userspace */
 161         wait_queue_head_t notification_waitq;   /* read() on the notification file blocks on this waitq */
 162         unsigned int q_len;                     /* events on the queue */
 163         unsigned int max_events;                /* maximum events allowed on the list */
 164         /*
 165          * Valid fsnotify group priorities.  Events are send in order from highest
 166          * priority to lowest priority.  We default to the lowest priority.
 167          */
 168         #define FS_PRIO_0       0 /* normal notifiers, no permissions */
 169         #define FS_PRIO_1       1 /* fanotify content based access control */
 170         #define FS_PRIO_2       2 /* fanotify pre-content access */
 171         unsigned int priority;
 172         bool shutdown;          /* group is being shut down, don't queue more events */
 173
 174         /* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
 175         struct mutex mark_mutex;        /* protect marks_list */
 176         atomic_t num_marks;             /* 1 for each mark and 1 for not being
 177                                          * past the point of no return when freeing
 178                                          * a group */
 179         atomic_t user_waits;            /* Number of tasks waiting for user
 180                                          * response */
 181         struct list_head marks_list;    /* all inode marks for this group */
 182
 183         struct fasync_struct *fsn_fa;    /* async notification */
 184
 185         struct fsnotify_event *overflow_event;  /* Event we queue when the
 186                                                  * notification list is too
 187                                                  * full */
 188
 189         struct mem_cgroup *memcg;       /* memcg to charge allocations */
 190
 191         /* groups can define private fields here or use the void *private */
 192         union {
 193                 void *private;
 194 #ifdef CONFIG_INOTIFY_USER
 195                 struct inotify_group_private_data {
 196                         spinlock_t      idr_lock;
 197                         struct idr      idr;
 198                         struct ucounts *ucounts;
 199                 } inotify_data;
 200 #endif
 201 #ifdef CONFIG_FANOTIFY
 202                 struct fanotify_group_private_data {
 203                         /* allows a group to block waiting for a userspace response */
 204                         struct list_head access_list;
 205                         wait_queue_head_t access_waitq;
 206                         int flags;           /* flags from fanotify_init() */
 207                         int f_flags; /* event_f_flags from fanotify_init() */
 208                         unsigned int max_marks;
 209                         struct user_struct *user;
 210                 } fanotify_data;
 211 #endif /* CONFIG_FANOTIFY */
 212         };
 213 };
 214
 215 /* when calling fsnotify tell it if the data is a path or inode */
 216 #define FSNOTIFY_EVENT_NONE     0
 217 #define FSNOTIFY_EVENT_PATH     1
 218 #define FSNOTIFY_EVENT_INODE    2
 219
 220 enum fsnotify_obj_type {
 221         FSNOTIFY_OBJ_TYPE_INODE,
 222         FSNOTIFY_OBJ_TYPE_VFSMOUNT,
 223         FSNOTIFY_OBJ_TYPE_SB,
 224         FSNOTIFY_OBJ_TYPE_COUNT,
 225         FSNOTIFY_OBJ_TYPE_DETACHED = FSNOTIFY_OBJ_TYPE_COUNT
 226 };
 227
 228 #define FSNOTIFY_OBJ_TYPE_INODE_FL      (1U << FSNOTIFY_OBJ_TYPE_INODE)
 229 #define FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL   (1U << FSNOTIFY_OBJ_TYPE_VFSMOUNT)
 230 #define FSNOTIFY_OBJ_TYPE_SB_FL         (1U << FSNOTIFY_OBJ_TYPE_SB)
 231 #define FSNOTIFY_OBJ_ALL_TYPES_MASK     ((1U << FSNOTIFY_OBJ_TYPE_COUNT) - 1)
 232
 233 static inline bool fsnotify_valid_obj_type(unsigned int type)
 234 {
 235         return (type < FSNOTIFY_OBJ_TYPE_COUNT);
 236 }
 237
 238 struct fsnotify_iter_info {
 239         struct fsnotify_mark *marks[FSNOTIFY_OBJ_TYPE_COUNT];
 240         unsigned int report_mask;
 241         int srcu_idx;
 242 };
 243
 244 static inline bool fsnotify_iter_should_report_type(
 245                 struct fsnotify_iter_info *iter_info, int type)
 246 {
 247         return (iter_info->report_mask & (1U << type));
 248 }
 249
 250 static inline void fsnotify_iter_set_report_type(
 251                 struct fsnotify_iter_info *iter_info, int type)
 252 {
 253         iter_info->report_mask |= (1U << type);
 254 }
 255
 256 static inline void fsnotify_iter_set_report_type_mark(
 257                 struct fsnotify_iter_info *iter_info, int type,
 258                 struct fsnotify_mark *mark)
 259 {
 260         iter_info->marks[type] = mark;
 261         iter_info->report_mask |= (1U << type);
 262 }
 263
 264 #define FSNOTIFY_ITER_FUNCS(name, NAME) \
 265 static inline struct fsnotify_mark *fsnotify_iter_##name##_mark( \
 266                 struct fsnotify_iter_info *iter_info) \
 267 { \
 268         return (iter_info->report_mask & FSNOTIFY_OBJ_TYPE_##NAME##_FL) ? \
 269                 iter_info->marks[FSNOTIFY_OBJ_TYPE_##NAME] : NULL; \
 270 }
 271
 272 FSNOTIFY_ITER_FUNCS(inode, INODE)
 273 FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)
 274 FSNOTIFY_ITER_FUNCS(sb, SB)
 275
 276 #define fsnotify_foreach_obj_type(type) \
 277         for (type = 0; type < FSNOTIFY_OBJ_TYPE_COUNT; type++)
 278
 279 /*
 280  * fsnotify_connp_t is what we embed in objects which connector can be attached
 281  * to. fsnotify_connp_t * is how we refer from connector back to object.
 282  */
 283 struct fsnotify_mark_connector;
 284 typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
 285
 286 /*
 287  * Inode/vfsmount/sb point to this structure which tracks all marks attached to
 288  * the inode/vfsmount/sb. The reference to inode/vfsmount/sb is held by this
 289  * structure. We destroy this structure when there are no more marks attached
 290  * to it. The structure is protected by fsnotify_mark_srcu.
 291  */
 292 struct fsnotify_mark_connector {
 293         spinlock_t lock;
 294         unsigned short type;    /* Type of object [lock] */
 295 #define FSNOTIFY_CONN_FLAG_HAS_FSID     0x01
 296         unsigned short flags;   /* flags [lock] */
 297         __kernel_fsid_t fsid;   /* fsid of filesystem containing object */
 298         union {
 299                 /* Object pointer [lock] */
 300                 fsnotify_connp_t *obj;
 301                 /* Used listing heads to free after srcu period expires */
 302                 struct fsnotify_mark_connector *destroy_next;
 303         };
 304         struct hlist_head list;
 305 };
 306
 307 /*
 308  * A mark is simply an object attached to an in core inode which allows an
 309  * fsnotify listener to indicate they are either no longer interested in events
 310  * of a type matching mask or only interested in those events.
 311  *
 312  * These are flushed when an inode is evicted from core and may be flushed
 313  * when the inode is modified (as seen by fsnotify_access).  Some fsnotify
 314  * users (such as dnotify) will flush these when the open fd is closed and not
 315  * at inode eviction or modification.
 316  *
 317  * Text in brackets is showing the lock(s) protecting modifications of a
 318  * particular entry. obj_lock means either inode->i_lock or
 319  * mnt->mnt_root->d_lock depending on the mark type.
 320  */
 321 struct fsnotify_mark {
 322         /* Mask this mark is for [mark->lock, group->mark_mutex] */
 323         __u32 mask;
 324         /* We hold one for presence in g_list. Also one ref for each 'thing'
 325          * in kernel that found and may be using this mark. */
 326         refcount_t refcnt;
 327         /* Group this mark is for. Set on mark creation, stable until last ref
 328          * is dropped */
 329         struct fsnotify_group *group;
 330         /* List of marks by group->marks_list. Also reused for queueing
 331          * mark into destroy_list when it's waiting for the end of SRCU period
 332          * before it can be freed. [group->mark_mutex] */
 333         struct list_head g_list;
 334         /* Protects inode / mnt pointers, flags, masks */
 335         spinlock_t lock;
 336         /* List of marks for inode / vfsmount [connector->lock, mark ref] */
 337         struct hlist_node obj_list;
 338         /* Head of list of marks for an object [mark ref] */
 339         struct fsnotify_mark_connector *connector;
 340         /* Events types to ignore [mark->lock, group->mark_mutex] */
 341         __u32 ignored_mask;
 342 #define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY  0x01
 343 #define FSNOTIFY_MARK_FLAG_ALIVE                0x02
 344 #define FSNOTIFY_MARK_FLAG_ATTACHED             0x04
 345         unsigned int flags;             /* flags [mark->lock] */
 346 };
 347
 348 #ifdef CONFIG_FSNOTIFY
 349
 350 /* called from the vfs helpers */
 351
 352 /* main fsnotify call to send events */
 353 extern int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
 354                     const struct qstr *name, u32 cookie);
 355 extern int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask);
 356 extern void __fsnotify_inode_delete(struct inode *inode);
 357 extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
 358 extern void fsnotify_sb_delete(struct super_block *sb);
 359 extern u32 fsnotify_get_cookie(void);
 360
 361 static inline int fsnotify_inode_watches_children(struct inode *inode)
 362 {
 363         /* FS_EVENT_ON_CHILD is set if the inode may care */
 364         if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
 365                 return 0;
 366         /* this inode might care about child events, does it care about the
 367          * specific set of events that can happen on a child? */
 368         return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
 369 }
 370
 371 /*
 372  * Update the dentry with a flag indicating the interest of its parent to receive
 373  * filesystem events when those events happens to this dentry->d_inode.
 374  */
 375 static inline void fsnotify_update_flags(struct dentry *dentry)
 376 {
 377         assert_spin_locked(&dentry->d_lock);
 378
 379         /*
 380          * Serialisation of setting PARENT_WATCHED on the dentries is provided
 381          * by d_lock. If inotify_inode_watched changes after we have taken
 382          * d_lock, the following __fsnotify_update_child_dentry_flags call will
 383          * find our entry, so it will spin until we complete here, and update
 384          * us with the new state.
 385          */
 386         if (fsnotify_inode_watches_children(dentry->d_parent->d_inode))
 387                 dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
 388         else
 389                 dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
 390 }
 391
 392 /* called from fsnotify listeners, such as fanotify or dnotify */
 393
 394 /* create a new group */
 395 extern struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops);
 396 /* get reference to a group */
 397 extern void fsnotify_get_group(struct fsnotify_group *group);
 398 /* drop reference on a group from fsnotify_alloc_group */
 399 extern void fsnotify_put_group(struct fsnotify_group *group);
 400 /* group destruction begins, stop queuing new events */
 401 extern void fsnotify_group_stop_queueing(struct fsnotify_group *group);
 402 /* destroy group */
 403 extern void fsnotify_destroy_group(struct fsnotify_group *group);
 404 /* fasync handler function */
 405 extern int fsnotify_fasync(int fd, struct file *file, int on);
 406 /* Free event from memory */
 407 extern void fsnotify_destroy_event(struct fsnotify_group *group,
 408                                    struct fsnotify_event *event);
 409 /* attach the event to the group notification queue */
 410 extern int fsnotify_add_event(struct fsnotify_group *group,
 411                               struct fsnotify_event *event,
 412                               int (*merge)(struct list_head *,
 413                                            struct fsnotify_event *));
 414 /* Queue overflow event to a notification group */
 415 static inline void fsnotify_queue_overflow(struct fsnotify_group *group)
 416 {
 417         fsnotify_add_event(group, group->overflow_event, NULL);
 418 }
 419
 420 /* true if the group notification queue is empty */
 421 extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
 422 /* return, but do not dequeue the first event on the notification queue */
 423 extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group);
 424 /* return AND dequeue the first event on the notification queue */
 425 extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group);
 426 /* Remove event queued in the notification list */
 427 extern void fsnotify_remove_queued_event(struct fsnotify_group *group,
 428                                          struct fsnotify_event *event);
 429
 430 /* functions used to manipulate the marks attached to inodes */
 431
 432 /* Get mask of events for a list of marks */
 433 extern __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn);
 434 /* Calculate mask of events for a list of marks */
 435 extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
 436 extern void fsnotify_init_mark(struct fsnotify_mark *mark,
 437                                struct fsnotify_group *group);
 438 /* Find mark belonging to given group in the list of marks */
 439 extern struct fsnotify_mark *fsnotify_find_mark(fsnotify_connp_t *connp,
 440                                                 struct fsnotify_group *group);
 441 /* Get cached fsid of filesystem containing object */
 442 extern int fsnotify_get_conn_fsid(const struct fsnotify_mark_connector *conn,
 443                                   __kernel_fsid_t *fsid);
 444 /* attach the mark to the object */
 445 extern int fsnotify_add_mark(struct fsnotify_mark *mark,
 446                              fsnotify_connp_t *connp, unsigned int type,
 447                              int allow_dups, __kernel_fsid_t *fsid);
 448 extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
 449                                     fsnotify_connp_t *connp,
 450                                     unsigned int type, int allow_dups,
 451                                     __kernel_fsid_t *fsid);
 452
 453 /* attach the mark to the inode */
 454 static inline int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
 455                                           struct inode *inode,
 456                                           int allow_dups)
 457 {
 458         return fsnotify_add_mark(mark, &inode->i_fsnotify_marks,
 459                                  FSNOTIFY_OBJ_TYPE_INODE, allow_dups, NULL);
 460 }
 461 static inline int fsnotify_add_inode_mark_locked(struct fsnotify_mark *mark,
 462                                                  struct inode *inode,
 463                                                  int allow_dups)
 464 {
 465         return fsnotify_add_mark_locked(mark, &inode->i_fsnotify_marks,
 466                                         FSNOTIFY_OBJ_TYPE_INODE, allow_dups,
 467                                         NULL);
 468 }
 469
 470 /* given a group and a mark, flag mark to be freed when all references are dropped */
 471 extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
 472                                   struct fsnotify_group *group);
 473 /* detach mark from inode / mount list, group list, drop inode reference */
 474 extern void fsnotify_detach_mark(struct fsnotify_mark *mark);
 475 /* free mark */
 476 extern void fsnotify_free_mark(struct fsnotify_mark *mark);
 477 /* Wait until all marks queued for destruction are destroyed */
 478 extern void fsnotify_wait_marks_destroyed(void);
 479 /* run all the marks in a group, and clear all of the marks attached to given object type */
 480 extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group, unsigned int type);
 481 /* run all the marks in a group, and clear all of the vfsmount marks */
 482 static inline void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
 483 {
 484         fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL);
 485 }
 486 /* run all the marks in a group, and clear all of the inode marks */
 487 static inline void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
 488 {
 489         fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_INODE_FL);
 490 }
 491 /* run all the marks in a group, and clear all of the sn marks */
 492 static inline void fsnotify_clear_sb_marks_by_group(struct fsnotify_group *group)
 493 {
 494         fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_SB_FL);
 495 }
 496 extern void fsnotify_get_mark(struct fsnotify_mark *mark);
 497 extern void fsnotify_put_mark(struct fsnotify_mark *mark);
 498 extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
 499 extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);
 500
 501 static inline void fsnotify_init_event(struct fsnotify_event *event,
 502                                        unsigned long objectid)
 503 {
 504         INIT_LIST_HEAD(&event->list);
 505         event->objectid = objectid;
 506 }
 507
 508 #else
 509
 510 static inline int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
 511                            const struct qstr *name, u32 cookie)
 512 {
 513         return 0;
 514 }
 515
 516 static inline int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
 517 {
 518         return 0;
 519 }
 520
 521 static inline void __fsnotify_inode_delete(struct inode *inode)
 522 {}
 523
 524 static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
 525 {}
 526
 527 static inline void fsnotify_sb_delete(struct super_block *sb)
 528 {}
 529
 530 static inline void fsnotify_update_flags(struct dentry *dentry)
 531 {}
 532
 533 static inline u32 fsnotify_get_cookie(void)
 534 {
 535         return 0;
 536 }
 537
 538 static inline void fsnotify_unmount_inodes(struct super_block *sb)
 539 {}
 540
 541 #endif  /* CONFIG_FSNOTIFY */
 542
 543 #endif  /* __KERNEL __ */
 544
 545 #endif  /* __LINUX_FSNOTIFY_BACKEND_H */