Line data Source code
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 : #include <linux/mempool.h>
23 : #include <linux/sched/mm.h>
24 :
25 : /*
26 : * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily
27 : * convert between them. dnotify only needs conversion at watch creation
28 : * so no perf loss there. fanotify isn't defined yet, so it can use the
29 : * wholes if it needs more events.
30 : */
31 : #define FS_ACCESS 0x00000001 /* File was accessed */
32 : #define FS_MODIFY 0x00000002 /* File was modified */
33 : #define FS_ATTRIB 0x00000004 /* Metadata changed */
34 : #define FS_CLOSE_WRITE 0x00000008 /* Writtable file was closed */
35 : #define FS_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
36 : #define FS_OPEN 0x00000020 /* File was opened */
37 : #define FS_MOVED_FROM 0x00000040 /* File was moved from X */
38 : #define FS_MOVED_TO 0x00000080 /* File was moved to Y */
39 : #define FS_CREATE 0x00000100 /* Subfile was created */
40 : #define FS_DELETE 0x00000200 /* Subfile was deleted */
41 : #define FS_DELETE_SELF 0x00000400 /* Self was deleted */
42 : #define FS_MOVE_SELF 0x00000800 /* Self was moved */
43 : #define FS_OPEN_EXEC 0x00001000 /* File was opened for exec */
44 :
45 : #define FS_UNMOUNT 0x00002000 /* inode on umount fs */
46 : #define FS_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
47 : #define FS_ERROR 0x00008000 /* Filesystem Error (fanotify) */
48 :
49 : /*
50 : * FS_IN_IGNORED overloads FS_ERROR. It is only used internally by inotify
51 : * which does not support FS_ERROR.
52 : */
53 : #define FS_IN_IGNORED 0x00008000 /* last inotify event here */
54 :
55 : #define FS_OPEN_PERM 0x00010000 /* open event in an permission hook */
56 : #define FS_ACCESS_PERM 0x00020000 /* access event in a permissions hook */
57 : #define FS_OPEN_EXEC_PERM 0x00040000 /* open/exec event in a permission hook */
58 :
59 : /*
60 : * Set on inode mark that cares about things that happen to its children.
61 : * Always set for dnotify and inotify.
62 : * Set on inode/sb/mount marks that care about parent/name info.
63 : */
64 : #define FS_EVENT_ON_CHILD 0x08000000
65 :
66 : #define FS_RENAME 0x10000000 /* File was renamed */
67 : #define FS_DN_MULTISHOT 0x20000000 /* dnotify multishot */
68 : #define FS_ISDIR 0x40000000 /* event occurred against dir */
69 :
70 : #define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO)
71 :
72 : /*
73 : * Directory entry modification events - reported only to directory
74 : * where entry is modified and not to a watching parent.
75 : * The watching parent may get an FS_ATTRIB|FS_EVENT_ON_CHILD event
76 : * when a directory entry inside a child subdir changes.
77 : */
78 : #define ALL_FSNOTIFY_DIRENT_EVENTS (FS_CREATE | FS_DELETE | FS_MOVE | FS_RENAME)
79 :
80 : #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \
81 : FS_OPEN_EXEC_PERM)
82 :
83 : /*
84 : * This is a list of all events that may get sent to a parent that is watching
85 : * with flag FS_EVENT_ON_CHILD based on fs event on a child of that directory.
86 : */
87 : #define FS_EVENTS_POSS_ON_CHILD (ALL_FSNOTIFY_PERM_EVENTS | \
88 : FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
89 : FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \
90 : FS_OPEN | FS_OPEN_EXEC)
91 :
92 : /*
93 : * This is a list of all events that may get sent with the parent inode as the
94 : * @to_tell argument of fsnotify().
95 : * It may include events that can be sent to an inode/sb/mount mark, but cannot
96 : * be sent to a parent watching children.
97 : */
98 : #define FS_EVENTS_POSS_TO_PARENT (FS_EVENTS_POSS_ON_CHILD)
99 :
100 : /* Events that can be reported to backends */
101 : #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \
102 : FS_EVENTS_POSS_ON_CHILD | \
103 : FS_DELETE_SELF | FS_MOVE_SELF | \
104 : FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
105 : FS_ERROR)
106 :
107 : /* Extra flags that may be reported with event or control handling of events */
108 : #define ALL_FSNOTIFY_FLAGS (FS_ISDIR | FS_EVENT_ON_CHILD | FS_DN_MULTISHOT)
109 :
110 : #define ALL_FSNOTIFY_BITS (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS)
111 :
112 : struct fsnotify_group;
113 : struct fsnotify_event;
114 : struct fsnotify_mark;
115 : struct fsnotify_event_private_data;
116 : struct fsnotify_fname;
117 : struct fsnotify_iter_info;
118 :
119 : struct mem_cgroup;
120 :
121 : /*
122 : * Each group much define these ops. The fsnotify infrastructure will call
123 : * these operations for each relevant group.
124 : *
125 : * handle_event - main call for a group to handle an fs event
126 : * @group: group to notify
127 : * @mask: event type and flags
128 : * @data: object that event happened on
129 : * @data_type: type of object for fanotify_data_XXX() accessors
130 : * @dir: optional directory associated with event -
131 : * if @file_name is not NULL, this is the directory that
132 : * @file_name is relative to
133 : * @file_name: optional file name associated with event
134 : * @cookie: inotify rename cookie
135 : * @iter_info: array of marks from this group that are interested in the event
136 : *
137 : * handle_inode_event - simple variant of handle_event() for groups that only
138 : * have inode marks and don't have ignore mask
139 : * @mark: mark to notify
140 : * @mask: event type and flags
141 : * @inode: inode that event happened on
142 : * @dir: optional directory associated with event -
143 : * if @file_name is not NULL, this is the directory that
144 : * @file_name is relative to.
145 : * Either @inode or @dir must be non-NULL.
146 : * @file_name: optional file name associated with event
147 : * @cookie: inotify rename cookie
148 : *
149 : * free_group_priv - called when a group refcnt hits 0 to clean up the private union
150 : * freeing_mark - called when a mark is being destroyed for some reason. The group
151 : * MUST be holding a reference on each mark and that reference must be
152 : * dropped in this function. inotify uses this function to send
153 : * userspace messages that marks have been removed.
154 : */
155 : struct fsnotify_ops {
156 : int (*handle_event)(struct fsnotify_group *group, u32 mask,
157 : const void *data, int data_type, struct inode *dir,
158 : const struct qstr *file_name, u32 cookie,
159 : struct fsnotify_iter_info *iter_info);
160 : int (*handle_inode_event)(struct fsnotify_mark *mark, u32 mask,
161 : struct inode *inode, struct inode *dir,
162 : const struct qstr *file_name, u32 cookie);
163 : void (*free_group_priv)(struct fsnotify_group *group);
164 : void (*freeing_mark)(struct fsnotify_mark *mark, struct fsnotify_group *group);
165 : void (*free_event)(struct fsnotify_group *group, struct fsnotify_event *event);
166 : /* called on final put+free to free memory */
167 : void (*free_mark)(struct fsnotify_mark *mark);
168 : };
169 :
170 : /*
171 : * all of the information about the original object we want to now send to
172 : * a group. If you want to carry more info from the accessing task to the
173 : * listener this structure is where you need to be adding fields.
174 : */
175 : struct fsnotify_event {
176 : struct list_head list;
177 : };
178 :
179 : /*
180 : * A group is a "thing" that wants to receive notification about filesystem
181 : * events. The mask holds the subset of event types this group cares about.
182 : * refcnt on a group is up to the implementor and at any moment if it goes 0
183 : * everything will be cleaned up.
184 : */
185 : struct fsnotify_group {
186 : const struct fsnotify_ops *ops; /* how this group handles things */
187 :
188 : /*
189 : * How the refcnt is used is up to each group. When the refcnt hits 0
190 : * fsnotify will clean up all of the resources associated with this group.
191 : * As an example, the dnotify group will always have a refcnt=1 and that
192 : * will never change. Inotify, on the other hand, has a group per
193 : * inotify_init() and the refcnt will hit 0 only when that fd has been
194 : * closed.
195 : */
196 : refcount_t refcnt; /* things with interest in this group */
197 :
198 : /* needed to send notification to userspace */
199 : spinlock_t notification_lock; /* protect the notification_list */
200 : struct list_head notification_list; /* list of event_holder this group needs to send to userspace */
201 : wait_queue_head_t notification_waitq; /* read() on the notification file blocks on this waitq */
202 : unsigned int q_len; /* events on the queue */
203 : unsigned int max_events; /* maximum events allowed on the list */
204 : /*
205 : * Valid fsnotify group priorities. Events are send in order from highest
206 : * priority to lowest priority. We default to the lowest priority.
207 : */
208 : #define FS_PRIO_0 0 /* normal notifiers, no permissions */
209 : #define FS_PRIO_1 1 /* fanotify content based access control */
210 : #define FS_PRIO_2 2 /* fanotify pre-content access */
211 : unsigned int priority;
212 : bool shutdown; /* group is being shut down, don't queue more events */
213 :
214 : #define FSNOTIFY_GROUP_USER 0x01 /* user allocated group */
215 : #define FSNOTIFY_GROUP_DUPS 0x02 /* allow multiple marks per object */
216 : #define FSNOTIFY_GROUP_NOFS 0x04 /* group lock is not direct reclaim safe */
217 : int flags;
218 : unsigned int owner_flags; /* stored flags of mark_mutex owner */
219 :
220 : /* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
221 : struct mutex mark_mutex; /* protect marks_list */
222 : atomic_t user_waits; /* Number of tasks waiting for user
223 : * response */
224 : struct list_head marks_list; /* all inode marks for this group */
225 :
226 : struct fasync_struct *fsn_fa; /* async notification */
227 :
228 : struct fsnotify_event *overflow_event; /* Event we queue when the
229 : * notification list is too
230 : * full */
231 :
232 : struct mem_cgroup *memcg; /* memcg to charge allocations */
233 :
234 : /* groups can define private fields here or use the void *private */
235 : union {
236 : void *private;
237 : #ifdef CONFIG_INOTIFY_USER
238 : struct inotify_group_private_data {
239 : spinlock_t idr_lock;
240 : struct idr idr;
241 : struct ucounts *ucounts;
242 : } inotify_data;
243 : #endif
244 : #ifdef CONFIG_FANOTIFY
245 : struct fanotify_group_private_data {
246 : /* Hash table of events for merge */
247 : struct hlist_head *merge_hash;
248 : /* allows a group to block waiting for a userspace response */
249 : struct list_head access_list;
250 : wait_queue_head_t access_waitq;
251 : int flags; /* flags from fanotify_init() */
252 : int f_flags; /* event_f_flags from fanotify_init() */
253 : struct ucounts *ucounts;
254 : mempool_t error_events_pool;
255 : } fanotify_data;
256 : #endif /* CONFIG_FANOTIFY */
257 : };
258 : };
259 :
260 : /*
261 : * These helpers are used to prevent deadlock when reclaiming inodes with
262 : * evictable marks of the same group that is allocating a new mark.
263 : */
264 0 : static inline void fsnotify_group_lock(struct fsnotify_group *group)
265 : {
266 0 : mutex_lock(&group->mark_mutex);
267 0 : if (group->flags & FSNOTIFY_GROUP_NOFS)
268 0 : group->owner_flags = memalloc_nofs_save();
269 0 : }
270 :
271 0 : static inline void fsnotify_group_unlock(struct fsnotify_group *group)
272 : {
273 0 : if (group->flags & FSNOTIFY_GROUP_NOFS)
274 0 : memalloc_nofs_restore(group->owner_flags);
275 0 : mutex_unlock(&group->mark_mutex);
276 0 : }
277 :
278 0 : static inline void fsnotify_group_assert_locked(struct fsnotify_group *group)
279 : {
280 0 : WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex));
281 0 : if (group->flags & FSNOTIFY_GROUP_NOFS)
282 0 : WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
283 0 : }
284 :
285 : /* When calling fsnotify tell it if the data is a path or inode */
286 : enum fsnotify_data_type {
287 : FSNOTIFY_EVENT_NONE,
288 : FSNOTIFY_EVENT_PATH,
289 : FSNOTIFY_EVENT_INODE,
290 : FSNOTIFY_EVENT_DENTRY,
291 : FSNOTIFY_EVENT_ERROR,
292 : };
293 :
294 : struct fs_error_report {
295 : int error;
296 : struct inode *inode;
297 : struct super_block *sb;
298 : };
299 :
300 : static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
301 : {
302 0 : switch (data_type) {
303 : case FSNOTIFY_EVENT_INODE:
304 : return (struct inode *)data;
305 : case FSNOTIFY_EVENT_DENTRY:
306 0 : return d_inode(data);
307 : case FSNOTIFY_EVENT_PATH:
308 0 : return d_inode(((const struct path *)data)->dentry);
309 : case FSNOTIFY_EVENT_ERROR:
310 0 : return ((struct fs_error_report *)data)->inode;
311 : default:
312 : return NULL;
313 : }
314 : }
315 :
316 : static inline struct dentry *fsnotify_data_dentry(const void *data, int data_type)
317 : {
318 0 : switch (data_type) {
319 : case FSNOTIFY_EVENT_DENTRY:
320 : /* Non const is needed for dget() */
321 : return (struct dentry *)data;
322 : case FSNOTIFY_EVENT_PATH:
323 0 : return ((const struct path *)data)->dentry;
324 : default:
325 : return NULL;
326 : }
327 : }
328 :
329 : static inline const struct path *fsnotify_data_path(const void *data,
330 : int data_type)
331 : {
332 0 : switch (data_type) {
333 : case FSNOTIFY_EVENT_PATH:
334 : return data;
335 : default:
336 : return NULL;
337 : }
338 : }
339 :
340 : static inline struct super_block *fsnotify_data_sb(const void *data,
341 : int data_type)
342 : {
343 0 : switch (data_type) {
344 : case FSNOTIFY_EVENT_INODE:
345 0 : return ((struct inode *)data)->i_sb;
346 : case FSNOTIFY_EVENT_DENTRY:
347 0 : return ((struct dentry *)data)->d_sb;
348 : case FSNOTIFY_EVENT_PATH:
349 0 : return ((const struct path *)data)->dentry->d_sb;
350 : case FSNOTIFY_EVENT_ERROR:
351 0 : return ((struct fs_error_report *) data)->sb;
352 : default:
353 : return NULL;
354 : }
355 : }
356 :
357 : static inline struct fs_error_report *fsnotify_data_error_report(
358 : const void *data,
359 : int data_type)
360 : {
361 : switch (data_type) {
362 : case FSNOTIFY_EVENT_ERROR:
363 : return (struct fs_error_report *) data;
364 : default:
365 : return NULL;
366 : }
367 : }
368 :
369 : /*
370 : * Index to merged marks iterator array that correlates to a type of watch.
371 : * The type of watched object can be deduced from the iterator type, but not
372 : * the other way around, because an event can match different watched objects
373 : * of the same object type.
374 : * For example, both parent and child are watching an object of type inode.
375 : */
376 : enum fsnotify_iter_type {
377 : FSNOTIFY_ITER_TYPE_INODE,
378 : FSNOTIFY_ITER_TYPE_VFSMOUNT,
379 : FSNOTIFY_ITER_TYPE_SB,
380 : FSNOTIFY_ITER_TYPE_PARENT,
381 : FSNOTIFY_ITER_TYPE_INODE2,
382 : FSNOTIFY_ITER_TYPE_COUNT
383 : };
384 :
385 : /* The type of object that a mark is attached to */
386 : enum fsnotify_obj_type {
387 : FSNOTIFY_OBJ_TYPE_ANY = -1,
388 : FSNOTIFY_OBJ_TYPE_INODE,
389 : FSNOTIFY_OBJ_TYPE_VFSMOUNT,
390 : FSNOTIFY_OBJ_TYPE_SB,
391 : FSNOTIFY_OBJ_TYPE_COUNT,
392 : FSNOTIFY_OBJ_TYPE_DETACHED = FSNOTIFY_OBJ_TYPE_COUNT
393 : };
394 :
395 : static inline bool fsnotify_valid_obj_type(unsigned int obj_type)
396 : {
397 : return (obj_type < FSNOTIFY_OBJ_TYPE_COUNT);
398 : }
399 :
400 : struct fsnotify_iter_info {
401 : struct fsnotify_mark *marks[FSNOTIFY_ITER_TYPE_COUNT];
402 : struct fsnotify_group *current_group;
403 : unsigned int report_mask;
404 : int srcu_idx;
405 : };
406 :
407 : static inline bool fsnotify_iter_should_report_type(
408 : struct fsnotify_iter_info *iter_info, int iter_type)
409 : {
410 0 : return (iter_info->report_mask & (1U << iter_type));
411 : }
412 :
413 : static inline void fsnotify_iter_set_report_type(
414 : struct fsnotify_iter_info *iter_info, int iter_type)
415 : {
416 0 : iter_info->report_mask |= (1U << iter_type);
417 : }
418 :
419 : static inline struct fsnotify_mark *fsnotify_iter_mark(
420 : struct fsnotify_iter_info *iter_info, int iter_type)
421 : {
422 0 : if (fsnotify_iter_should_report_type(iter_info, iter_type))
423 0 : return iter_info->marks[iter_type];
424 : return NULL;
425 : }
426 :
427 : static inline int fsnotify_iter_step(struct fsnotify_iter_info *iter, int type,
428 : struct fsnotify_mark **markp)
429 : {
430 0 : while (type < FSNOTIFY_ITER_TYPE_COUNT) {
431 0 : *markp = fsnotify_iter_mark(iter, type);
432 0 : if (*markp)
433 : break;
434 0 : type++;
435 : }
436 : return type;
437 : }
438 :
439 : #define FSNOTIFY_ITER_FUNCS(name, NAME) \
440 : static inline struct fsnotify_mark *fsnotify_iter_##name##_mark( \
441 : struct fsnotify_iter_info *iter_info) \
442 : { \
443 : return fsnotify_iter_mark(iter_info, FSNOTIFY_ITER_TYPE_##NAME); \
444 : }
445 :
446 0 : FSNOTIFY_ITER_FUNCS(inode, INODE)
447 0 : FSNOTIFY_ITER_FUNCS(parent, PARENT)
448 0 : FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)
449 0 : FSNOTIFY_ITER_FUNCS(sb, SB)
450 :
451 : #define fsnotify_foreach_iter_type(type) \
452 : for (type = 0; type < FSNOTIFY_ITER_TYPE_COUNT; type++)
453 : #define fsnotify_foreach_iter_mark_type(iter, mark, type) \
454 : for (type = 0; \
455 : type = fsnotify_iter_step(iter, type, &mark), \
456 : type < FSNOTIFY_ITER_TYPE_COUNT; \
457 : type++)
458 :
459 : /*
460 : * fsnotify_connp_t is what we embed in objects which connector can be attached
461 : * to. fsnotify_connp_t * is how we refer from connector back to object.
462 : */
463 : struct fsnotify_mark_connector;
464 : typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
465 :
466 : /*
467 : * Inode/vfsmount/sb point to this structure which tracks all marks attached to
468 : * the inode/vfsmount/sb. The reference to inode/vfsmount/sb is held by this
469 : * structure. We destroy this structure when there are no more marks attached
470 : * to it. The structure is protected by fsnotify_mark_srcu.
471 : */
472 : struct fsnotify_mark_connector {
473 : spinlock_t lock;
474 : unsigned short type; /* Type of object [lock] */
475 : #define FSNOTIFY_CONN_FLAG_HAS_FSID 0x01
476 : #define FSNOTIFY_CONN_FLAG_HAS_IREF 0x02
477 : unsigned short flags; /* flags [lock] */
478 : __kernel_fsid_t fsid; /* fsid of filesystem containing object */
479 : union {
480 : /* Object pointer [lock] */
481 : fsnotify_connp_t *obj;
482 : /* Used listing heads to free after srcu period expires */
483 : struct fsnotify_mark_connector *destroy_next;
484 : };
485 : struct hlist_head list;
486 : };
487 :
488 : /*
489 : * A mark is simply an object attached to an in core inode which allows an
490 : * fsnotify listener to indicate they are either no longer interested in events
491 : * of a type matching mask or only interested in those events.
492 : *
493 : * These are flushed when an inode is evicted from core and may be flushed
494 : * when the inode is modified (as seen by fsnotify_access). Some fsnotify
495 : * users (such as dnotify) will flush these when the open fd is closed and not
496 : * at inode eviction or modification.
497 : *
498 : * Text in brackets is showing the lock(s) protecting modifications of a
499 : * particular entry. obj_lock means either inode->i_lock or
500 : * mnt->mnt_root->d_lock depending on the mark type.
501 : */
502 : struct fsnotify_mark {
503 : /* Mask this mark is for [mark->lock, group->mark_mutex] */
504 : __u32 mask;
505 : /* We hold one for presence in g_list. Also one ref for each 'thing'
506 : * in kernel that found and may be using this mark. */
507 : refcount_t refcnt;
508 : /* Group this mark is for. Set on mark creation, stable until last ref
509 : * is dropped */
510 : struct fsnotify_group *group;
511 : /* List of marks by group->marks_list. Also reused for queueing
512 : * mark into destroy_list when it's waiting for the end of SRCU period
513 : * before it can be freed. [group->mark_mutex] */
514 : struct list_head g_list;
515 : /* Protects inode / mnt pointers, flags, masks */
516 : spinlock_t lock;
517 : /* List of marks for inode / vfsmount [connector->lock, mark ref] */
518 : struct hlist_node obj_list;
519 : /* Head of list of marks for an object [mark ref] */
520 : struct fsnotify_mark_connector *connector;
521 : /* Events types and flags to ignore [mark->lock, group->mark_mutex] */
522 : __u32 ignore_mask;
523 : /* General fsnotify mark flags */
524 : #define FSNOTIFY_MARK_FLAG_ALIVE 0x0001
525 : #define FSNOTIFY_MARK_FLAG_ATTACHED 0x0002
526 : /* inotify mark flags */
527 : #define FSNOTIFY_MARK_FLAG_EXCL_UNLINK 0x0010
528 : #define FSNOTIFY_MARK_FLAG_IN_ONESHOT 0x0020
529 : /* fanotify mark flags */
530 : #define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x0100
531 : #define FSNOTIFY_MARK_FLAG_NO_IREF 0x0200
532 : #define FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS 0x0400
533 : unsigned int flags; /* flags [mark->lock] */
534 : };
535 :
536 : #ifdef CONFIG_FSNOTIFY
537 :
538 : /* called from the vfs helpers */
539 :
540 : /* main fsnotify call to send events */
541 : extern int fsnotify(__u32 mask, const void *data, int data_type,
542 : struct inode *dir, const struct qstr *name,
543 : struct inode *inode, u32 cookie);
544 : extern int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
545 : int data_type);
546 : extern void __fsnotify_inode_delete(struct inode *inode);
547 : extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
548 : extern void fsnotify_sb_delete(struct super_block *sb);
549 : extern u32 fsnotify_get_cookie(void);
550 :
551 : static inline __u32 fsnotify_parent_needed_mask(__u32 mask)
552 : {
553 : /* FS_EVENT_ON_CHILD is set on marks that want parent/name info */
554 0 : if (!(mask & FS_EVENT_ON_CHILD))
555 : return 0;
556 : /*
557 : * This object might be watched by a mark that cares about parent/name
558 : * info, does it care about the specific set of events that can be
559 : * reported with parent/name info?
560 : */
561 0 : return mask & FS_EVENTS_POSS_TO_PARENT;
562 : }
563 :
564 : static inline int fsnotify_inode_watches_children(struct inode *inode)
565 : {
566 : /* FS_EVENT_ON_CHILD is set if the inode may care */
567 32 : if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
568 : return 0;
569 : /* this inode might care about child events, does it care about the
570 : * specific set of events that can happen on a child? */
571 0 : return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
572 : }
573 :
574 : /*
575 : * Update the dentry with a flag indicating the interest of its parent to receive
576 : * filesystem events when those events happens to this dentry->d_inode.
577 : */
578 : static inline void fsnotify_update_flags(struct dentry *dentry)
579 : {
580 : assert_spin_locked(&dentry->d_lock);
581 :
582 : /*
583 : * Serialisation of setting PARENT_WATCHED on the dentries is provided
584 : * by d_lock. If inotify_inode_watched changes after we have taken
585 : * d_lock, the following __fsnotify_update_child_dentry_flags call will
586 : * find our entry, so it will spin until we complete here, and update
587 : * us with the new state.
588 : */
589 64 : if (fsnotify_inode_watches_children(dentry->d_parent->d_inode))
590 0 : dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
591 : else
592 32 : dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
593 : }
594 :
595 : /* called from fsnotify listeners, such as fanotify or dnotify */
596 :
597 : /* create a new group */
598 : extern struct fsnotify_group *fsnotify_alloc_group(
599 : const struct fsnotify_ops *ops,
600 : int flags);
601 : /* get reference to a group */
602 : extern void fsnotify_get_group(struct fsnotify_group *group);
603 : /* drop reference on a group from fsnotify_alloc_group */
604 : extern void fsnotify_put_group(struct fsnotify_group *group);
605 : /* group destruction begins, stop queuing new events */
606 : extern void fsnotify_group_stop_queueing(struct fsnotify_group *group);
607 : /* destroy group */
608 : extern void fsnotify_destroy_group(struct fsnotify_group *group);
609 : /* fasync handler function */
610 : extern int fsnotify_fasync(int fd, struct file *file, int on);
611 : /* Free event from memory */
612 : extern void fsnotify_destroy_event(struct fsnotify_group *group,
613 : struct fsnotify_event *event);
614 : /* attach the event to the group notification queue */
615 : extern int fsnotify_insert_event(struct fsnotify_group *group,
616 : struct fsnotify_event *event,
617 : int (*merge)(struct fsnotify_group *,
618 : struct fsnotify_event *),
619 : void (*insert)(struct fsnotify_group *,
620 : struct fsnotify_event *));
621 :
622 : static inline int fsnotify_add_event(struct fsnotify_group *group,
623 : struct fsnotify_event *event,
624 : int (*merge)(struct fsnotify_group *,
625 : struct fsnotify_event *))
626 : {
627 0 : return fsnotify_insert_event(group, event, merge, NULL);
628 : }
629 :
630 : /* Queue overflow event to a notification group */
631 : static inline void fsnotify_queue_overflow(struct fsnotify_group *group)
632 : {
633 0 : fsnotify_add_event(group, group->overflow_event, NULL);
634 : }
635 :
636 : static inline bool fsnotify_is_overflow_event(u32 mask)
637 : {
638 : return mask & FS_Q_OVERFLOW;
639 : }
640 :
641 : static inline bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group)
642 : {
643 : assert_spin_locked(&group->notification_lock);
644 :
645 0 : return list_empty(&group->notification_list);
646 : }
647 :
648 : extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
649 : /* return, but do not dequeue the first event on the notification queue */
650 : extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group);
651 : /* return AND dequeue the first event on the notification queue */
652 : extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group);
653 : /* Remove event queued in the notification list */
654 : extern void fsnotify_remove_queued_event(struct fsnotify_group *group,
655 : struct fsnotify_event *event);
656 :
657 : /* functions used to manipulate the marks attached to inodes */
658 :
659 : /*
660 : * Canonical "ignore mask" including event flags.
661 : *
662 : * Note the subtle semantic difference from the legacy ->ignored_mask.
663 : * ->ignored_mask traditionally only meant which events should be ignored,
664 : * while ->ignore_mask also includes flags regarding the type of objects on
665 : * which events should be ignored.
666 : */
667 : static inline __u32 fsnotify_ignore_mask(struct fsnotify_mark *mark)
668 : {
669 0 : __u32 ignore_mask = mark->ignore_mask;
670 :
671 : /* The event flags in ignore mask take effect */
672 0 : if (mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
673 : return ignore_mask;
674 :
675 : /*
676 : * Legacy behavior:
677 : * - Always ignore events on dir
678 : * - Ignore events on child if parent is watching children
679 : */
680 0 : ignore_mask |= FS_ISDIR;
681 0 : ignore_mask &= ~FS_EVENT_ON_CHILD;
682 0 : ignore_mask |= mark->mask & FS_EVENT_ON_CHILD;
683 :
684 : return ignore_mask;
685 : }
686 :
687 : /* Legacy ignored_mask - only event types to ignore */
688 : static inline __u32 fsnotify_ignored_events(struct fsnotify_mark *mark)
689 : {
690 0 : return mark->ignore_mask & ALL_FSNOTIFY_EVENTS;
691 : }
692 :
693 : /*
694 : * Check if mask (or ignore mask) should be applied depending if victim is a
695 : * directory and whether it is reported to a watching parent.
696 : */
697 : static inline bool fsnotify_mask_applicable(__u32 mask, bool is_dir,
698 : int iter_type)
699 : {
700 : /* Should mask be applied to a directory? */
701 0 : if (is_dir && !(mask & FS_ISDIR))
702 : return false;
703 :
704 : /* Should mask be applied to a child? */
705 0 : if (iter_type == FSNOTIFY_ITER_TYPE_PARENT &&
706 0 : !(mask & FS_EVENT_ON_CHILD))
707 : return false;
708 :
709 : return true;
710 : }
711 :
712 : /*
713 : * Effective ignore mask taking into account if event victim is a
714 : * directory and whether it is reported to a watching parent.
715 : */
716 0 : static inline __u32 fsnotify_effective_ignore_mask(struct fsnotify_mark *mark,
717 : bool is_dir, int iter_type)
718 : {
719 0 : __u32 ignore_mask = fsnotify_ignored_events(mark);
720 :
721 0 : if (!ignore_mask)
722 : return 0;
723 :
724 : /* For non-dir and non-child, no need to consult the event flags */
725 0 : if (!is_dir && iter_type != FSNOTIFY_ITER_TYPE_PARENT)
726 : return ignore_mask;
727 :
728 0 : ignore_mask = fsnotify_ignore_mask(mark);
729 0 : if (!fsnotify_mask_applicable(ignore_mask, is_dir, iter_type))
730 : return 0;
731 :
732 0 : return ignore_mask & ALL_FSNOTIFY_EVENTS;
733 : }
734 :
735 : /* Get mask for calculating object interest taking ignore mask into account */
736 : static inline __u32 fsnotify_calc_mask(struct fsnotify_mark *mark)
737 : {
738 0 : __u32 mask = mark->mask;
739 :
740 0 : if (!fsnotify_ignored_events(mark))
741 : return mask;
742 :
743 : /* Interest in FS_MODIFY may be needed for clearing ignore mask */
744 0 : if (!(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
745 0 : mask |= FS_MODIFY;
746 :
747 : /*
748 : * If mark is interested in ignoring events on children, the object must
749 : * show interest in those events for fsnotify_parent() to notice it.
750 : */
751 0 : return mask | mark->ignore_mask;
752 : }
753 :
754 : /* Get mask of events for a list of marks */
755 : extern __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn);
756 : /* Calculate mask of events for a list of marks */
757 : extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
758 : extern void fsnotify_init_mark(struct fsnotify_mark *mark,
759 : struct fsnotify_group *group);
760 : /* Find mark belonging to given group in the list of marks */
761 : extern struct fsnotify_mark *fsnotify_find_mark(fsnotify_connp_t *connp,
762 : struct fsnotify_group *group);
763 : /* Get cached fsid of filesystem containing object */
764 : extern int fsnotify_get_conn_fsid(const struct fsnotify_mark_connector *conn,
765 : __kernel_fsid_t *fsid);
766 : /* attach the mark to the object */
767 : extern int fsnotify_add_mark(struct fsnotify_mark *mark,
768 : fsnotify_connp_t *connp, unsigned int obj_type,
769 : int add_flags, __kernel_fsid_t *fsid);
770 : extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
771 : fsnotify_connp_t *connp,
772 : unsigned int obj_type, int add_flags,
773 : __kernel_fsid_t *fsid);
774 :
775 : /* attach the mark to the inode */
776 : static inline int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
777 : struct inode *inode,
778 : int add_flags)
779 : {
780 : return fsnotify_add_mark(mark, &inode->i_fsnotify_marks,
781 : FSNOTIFY_OBJ_TYPE_INODE, add_flags, NULL);
782 : }
783 : static inline int fsnotify_add_inode_mark_locked(struct fsnotify_mark *mark,
784 : struct inode *inode,
785 : int add_flags)
786 : {
787 0 : return fsnotify_add_mark_locked(mark, &inode->i_fsnotify_marks,
788 : FSNOTIFY_OBJ_TYPE_INODE, add_flags,
789 : NULL);
790 : }
791 :
792 : /* given a group and a mark, flag mark to be freed when all references are dropped */
793 : extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
794 : struct fsnotify_group *group);
795 : /* detach mark from inode / mount list, group list, drop inode reference */
796 : extern void fsnotify_detach_mark(struct fsnotify_mark *mark);
797 : /* free mark */
798 : extern void fsnotify_free_mark(struct fsnotify_mark *mark);
799 : /* Wait until all marks queued for destruction are destroyed */
800 : extern void fsnotify_wait_marks_destroyed(void);
801 : /* Clear all of the marks of a group attached to a given object type */
802 : extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
803 : unsigned int obj_type);
804 : /* run all the marks in a group, and clear all of the vfsmount marks */
805 : static inline void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
806 : {
807 : fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT);
808 : }
809 : /* run all the marks in a group, and clear all of the inode marks */
810 : static inline void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
811 : {
812 : fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_INODE);
813 : }
814 : /* run all the marks in a group, and clear all of the sn marks */
815 : static inline void fsnotify_clear_sb_marks_by_group(struct fsnotify_group *group)
816 : {
817 : fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_SB);
818 : }
819 : extern void fsnotify_get_mark(struct fsnotify_mark *mark);
820 : extern void fsnotify_put_mark(struct fsnotify_mark *mark);
821 : extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
822 : extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);
823 :
824 : static inline void fsnotify_init_event(struct fsnotify_event *event)
825 : {
826 0 : INIT_LIST_HEAD(&event->list);
827 : }
828 :
829 : #else
830 :
831 : static inline int fsnotify(__u32 mask, const void *data, int data_type,
832 : struct inode *dir, const struct qstr *name,
833 : struct inode *inode, u32 cookie)
834 : {
835 : return 0;
836 : }
837 :
838 : static inline int __fsnotify_parent(struct dentry *dentry, __u32 mask,
839 : const void *data, int data_type)
840 : {
841 : return 0;
842 : }
843 :
844 : static inline void __fsnotify_inode_delete(struct inode *inode)
845 : {}
846 :
847 : static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
848 : {}
849 :
850 : static inline void fsnotify_sb_delete(struct super_block *sb)
851 : {}
852 :
853 : static inline void fsnotify_update_flags(struct dentry *dentry)
854 : {}
855 :
856 : static inline u32 fsnotify_get_cookie(void)
857 : {
858 : return 0;
859 : }
860 :
861 : static inline void fsnotify_unmount_inodes(struct super_block *sb)
862 : {}
863 :
864 : #endif /* CONFIG_FSNOTIFY */
865 :
866 : #endif /* __KERNEL __ */
867 :
868 : #endif /* __LINUX_FSNOTIFY_BACKEND_H */
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