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2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771 
 kernel/fs/notify/fsnotify.c
....@@ -1,19 +1,6 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
3
- *
4
- *  This program is free software; you can redistribute it and/or modify
5
- *  it under the terms of the GNU General Public License as published by
6
- *  the Free Software Foundation; either version 2, or (at your option)
7
- *  any later version.
8
- *
9
- *  This program is distributed in the hope that it will be useful,
10
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12
- *  GNU General Public License for more details.
13
- *
14
- *  You should have received a copy of the GNU General Public License
15
- *  along with this program; see the file COPYING.  If not, write to
16
- *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
174  */
185 
196 #include <linux/dcache.h>
....@@ -48,7 +35,7 @@
4835  * Called during unmount with no locks held, so needs to be safe against
4936  * concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block.
5037  */
51
-void fsnotify_unmount_inodes(struct super_block *sb)
38
+static void fsnotify_unmount_inodes(struct super_block *sb)
5239 {
5340 	struct inode *inode, *iput_inode = NULL;
5441 
....@@ -70,6 +57,9 @@
7057 		 * doing an __iget/iput with SB_ACTIVE clear would actually
7158 		 * evict all inodes with zero i_count from icache which is
7259 		 * unnecessarily violent and may in fact be illegal to do.
60
+		 * However, we should have been called /after/ evict_inodes
61
+		 * removed all zero refcount inodes, in any case.  Test to
62
+		 * be sure.
7363 		 */
7464 		if (!atomic_read(&inode->i_count)) {
7565 			spin_unlock(&inode->i_lock);
....@@ -84,7 +74,7 @@
8474 			iput(iput_inode);
8575 
8676 		/* for each watch, send FS_UNMOUNT and then remove it */
87
-		fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
77
+		fsnotify_inode(inode, FS_UNMOUNT);
8878 
8979 		fsnotify_inode_delete(inode);
9080 
....@@ -100,6 +90,12 @@
10090 	/* Wait for outstanding inode references from connectors */
10191 	wait_var_event(&sb->s_fsnotify_inode_refs,
10292 		       !atomic_long_read(&sb->s_fsnotify_inode_refs));
93
+}
94
+
95
+void fsnotify_sb_delete(struct super_block *sb)
96
+{
97
+	fsnotify_unmount_inodes(sb);
98
+	fsnotify_clear_marks_by_sb(sb);
10399 }
104100 
105101 /*
....@@ -146,52 +142,178 @@
146142 	spin_unlock(&inode->i_lock);
147143 }
148144 
149
-/* Notify this dentry's parent about a child's events. */
150
-int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
145
+/* Are inode/sb/mount interested in parent and name info with this event? */
146
+static bool fsnotify_event_needs_parent(struct inode *inode, struct mount *mnt,
147
+					__u32 mask)
151148 {
149
+	__u32 marks_mask = 0;
150
+
151
+	/* We only send parent/name to inode/sb/mount for events on non-dir */
152
+	if (mask & FS_ISDIR)
153
+		return false;
154
+
155
+	/*
156
+	 * All events that are possible on child can also may be reported with
157
+	 * parent/name info to inode/sb/mount.  Otherwise, a watching parent
158
+	 * could result in events reported with unexpected name info to sb/mount.
159
+	 */
160
+	BUILD_BUG_ON(FS_EVENTS_POSS_ON_CHILD & ~FS_EVENTS_POSS_TO_PARENT);
161
+
162
+	/* Did either inode/sb/mount subscribe for events with parent/name? */
163
+	marks_mask |= fsnotify_parent_needed_mask(inode->i_fsnotify_mask);
164
+	marks_mask |= fsnotify_parent_needed_mask(inode->i_sb->s_fsnotify_mask);
165
+	if (mnt)
166
+		marks_mask |= fsnotify_parent_needed_mask(mnt->mnt_fsnotify_mask);
167
+
168
+	/* Did they subscribe for this event with parent/name info? */
169
+	return mask & marks_mask;
170
+}
171
+
172
+/*
173
+ * Notify this dentry's parent about a child's events with child name info
174
+ * if parent is watching or if inode/sb/mount are interested in events with
175
+ * parent and name info.
176
+ *
177
+ * Notify only the child without name info if parent is not watching and
178
+ * inode/sb/mount are not interested in events with parent and name info.
179
+ */
180
+int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
181
+		      int data_type)
182
+{
183
+	const struct path *path = fsnotify_data_path(data, data_type);
184
+	struct mount *mnt = path ? real_mount(path->mnt) : NULL;
185
+	struct inode *inode = d_inode(dentry);
152186 	struct dentry *parent;
153
-	struct inode *p_inode;
187
+	bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED;
188
+	bool parent_needed, parent_interested;
189
+	__u32 p_mask;
190
+	struct inode *p_inode = NULL;
191
+	struct name_snapshot name;
192
+	struct qstr *file_name = NULL;
154193 	int ret = 0;
155194 
156
-	if (!dentry)
157
-		dentry = path->dentry;
158
-
159
-	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
195
+	/*
196
+	 * Do inode/sb/mount care about parent and name info on non-dir?
197
+	 * Do they care about any event at all?
198
+	 */
199
+	if (!inode->i_fsnotify_marks && !inode->i_sb->s_fsnotify_marks &&
200
+	    (!mnt || !mnt->mnt_fsnotify_marks) && !parent_watched)
160201 		return 0;
161202 
203
+	parent = NULL;
204
+	parent_needed = fsnotify_event_needs_parent(inode, mnt, mask);
205
+	if (!parent_watched && !parent_needed)
206
+		goto notify;
207
+
208
+	/* Does parent inode care about events on children? */
162209 	parent = dget_parent(dentry);
163210 	p_inode = parent->d_inode;
164
-
165
-	if (unlikely(!fsnotify_inode_watches_children(p_inode))) {
211
+	p_mask = fsnotify_inode_watches_children(p_inode);
212
+	if (unlikely(parent_watched && !p_mask))
166213 		__fsnotify_update_child_dentry_flags(p_inode);
167
-	} else if (p_inode->i_fsnotify_mask & mask & ALL_FSNOTIFY_EVENTS) {
168
-		struct name_snapshot name;
169214 
170
-		/* we are notifying a parent so come up with the new mask which
171
-		 * specifies these are events which came from a child. */
172
-		mask |= FS_EVENT_ON_CHILD;
215
+	/*
216
+	 * Include parent/name in notification either if some notification
217
+	 * groups require parent info or the parent is interested in this event.
218
+	 */
219
+	parent_interested = mask & p_mask & ALL_FSNOTIFY_EVENTS;
220
+	if (parent_needed || parent_interested) {
221
+		/* When notifying parent, child should be passed as data */
222
+		WARN_ON_ONCE(inode != fsnotify_data_inode(data, data_type));
173223 
224
+		/* Notify both parent and child with child name info */
174225 		take_dentry_name_snapshot(&name, dentry);
175
-		if (path)
176
-			ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
177
-				       name.name, 0);
178
-		else
179
-			ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
180
-				       name.name, 0);
181
-		release_dentry_name_snapshot(&name);
226
+		file_name = &name.name;
227
+		if (parent_interested)
228
+			mask |= FS_EVENT_ON_CHILD;
182229 	}
183230 
231
+notify:
232
+	ret = fsnotify(mask, data, data_type, p_inode, file_name, inode, 0);
233
+
234
+	if (file_name)
235
+		release_dentry_name_snapshot(&name);
184236 	dput(parent);
185237 
186238 	return ret;
187239 }
188240 EXPORT_SYMBOL_GPL(__fsnotify_parent);
189241 
190
-static int send_to_group(struct inode *to_tell,
191
-			 __u32 mask, const void *data,
192
-			 int data_is, u32 cookie,
193
-			 const unsigned char *file_name,
194
-			 struct fsnotify_iter_info *iter_info)
242
+static int fsnotify_handle_inode_event(struct fsnotify_group *group,
243
+				       struct fsnotify_mark *inode_mark,
244
+				       u32 mask, const void *data, int data_type,
245
+				       struct inode *dir, const struct qstr *name,
246
+				       u32 cookie)
247
+{
248
+	const struct path *path = fsnotify_data_path(data, data_type);
249
+	struct inode *inode = fsnotify_data_inode(data, data_type);
250
+	const struct fsnotify_ops *ops = group->ops;
251
+
252
+	if (WARN_ON_ONCE(!ops->handle_inode_event))
253
+		return 0;
254
+
255
+	if ((inode_mark->mask & FS_EXCL_UNLINK) &&
256
+	    path && d_unlinked(path->dentry))
257
+		return 0;
258
+
259
+	/* Check interest of this mark in case event was sent with two marks */
260
+	if (!(mask & inode_mark->mask & ALL_FSNOTIFY_EVENTS))
261
+		return 0;
262
+
263
+	return ops->handle_inode_event(inode_mark, mask, inode, dir, name, cookie);
264
+}
265
+
266
+static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
267
+				 const void *data, int data_type,
268
+				 struct inode *dir, const struct qstr *name,
269
+				 u32 cookie, struct fsnotify_iter_info *iter_info)
270
+{
271
+	struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info);
272
+	struct fsnotify_mark *parent_mark = fsnotify_iter_parent_mark(iter_info);
273
+	int ret;
274
+
275
+	if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) ||
276
+	    WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info)))
277
+		return 0;
278
+
279
+	if (parent_mark) {
280
+		/*
281
+		 * parent_mark indicates that the parent inode is watching
282
+		 * children and interested in this event, which is an event
283
+		 * possible on child. But is *this mark* watching children and
284
+		 * interested in this event?
285
+		 */
286
+		if (parent_mark->mask & FS_EVENT_ON_CHILD) {
287
+			ret = fsnotify_handle_inode_event(group, parent_mark, mask,
288
+							  data, data_type, dir, name, 0);
289
+			if (ret)
290
+				return ret;
291
+		}
292
+		if (!inode_mark)
293
+			return 0;
294
+	}
295
+
296
+	if (mask & FS_EVENT_ON_CHILD) {
297
+		/*
298
+		 * Some events can be sent on both parent dir and child marks
299
+		 * (e.g. FS_ATTRIB).  If both parent dir and child are
300
+		 * watching, report the event once to parent dir with name (if
301
+		 * interested) and once to child without name (if interested).
302
+		 * The child watcher is expecting an event without a file name
303
+		 * and without the FS_EVENT_ON_CHILD flag.
304
+		 */
305
+		mask &= ~FS_EVENT_ON_CHILD;
306
+		dir = NULL;
307
+		name = NULL;
308
+	}
309
+
310
+	return fsnotify_handle_inode_event(group, inode_mark, mask, data, data_type,
311
+					   dir, name, cookie);
312
+}
313
+
314
+static int send_to_group(__u32 mask, const void *data, int data_type,
315
+			 struct inode *dir, const struct qstr *file_name,
316
+			 u32 cookie, struct fsnotify_iter_info *iter_info)
195317 {
196318 	struct fsnotify_group *group = NULL;
197319 	__u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
....@@ -227,16 +349,20 @@
227349 		}
228350 	}
229351 
230
-	pr_debug("%s: group=%p to_tell=%p mask=%x marks_mask=%x marks_ignored_mask=%x"
231
-		 " data=%p data_is=%d cookie=%d\n",
232
-		 __func__, group, to_tell, mask, marks_mask, marks_ignored_mask,
233
-		 data, data_is, cookie);
352
+	pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignored_mask=%x data=%p data_type=%d dir=%p cookie=%d\n",
353
+		 __func__, group, mask, marks_mask, marks_ignored_mask,
354
+		 data, data_type, dir, cookie);
234355 
235356 	if (!(test_mask & marks_mask & ~marks_ignored_mask))
236357 		return 0;
237358 
238
-	return group->ops->handle_event(group, to_tell, mask, data, data_is,
239
-					file_name, cookie, iter_info);
359
+	if (group->ops->handle_event) {
360
+		return group->ops->handle_event(group, mask, data, data_type, dir,
361
+						file_name, cookie, iter_info);
362
+	}
363
+
364
+	return fsnotify_handle_event(group, mask, data, data_type, dir,
365
+				     file_name, cookie, iter_info);
240366 }
241367 
242368 static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
....@@ -314,27 +440,50 @@
314440 }
315441 
316442 /*
317
- * This is the main call to fsnotify.  The VFS calls into hook specific functions
318
- * in linux/fsnotify.h.  Those functions then in turn call here.  Here will call
319
- * out to all of the registered fsnotify_group.  Those groups can then use the
320
- * notification event in whatever means they feel necessary.
443
+ * fsnotify - This is the main call to fsnotify.
444
+ *
445
+ * The VFS calls into hook specific functions in linux/fsnotify.h.
446
+ * Those functions then in turn call here.  Here will call out to all of the
447
+ * registered fsnotify_group.  Those groups can then use the notification event
448
+ * in whatever means they feel necessary.
449
+ *
450
+ * @mask:	event type and flags
451
+ * @data:	object that event happened on
452
+ * @data_type:	type of object for fanotify_data_XXX() accessors
453
+ * @dir:	optional directory associated with event -
454
+ *		if @file_name is not NULL, this is the directory that
455
+ *		@file_name is relative to
456
+ * @file_name:	optional file name associated with event
457
+ * @inode:	optional inode associated with event -
458
+ *		either @dir or @inode must be non-NULL.
459
+ *		if both are non-NULL event may be reported to both.
460
+ * @cookie:	inotify rename cookie
321461  */
322
-int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
323
-	     const unsigned char *file_name, u32 cookie)
462
+int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
463
+	     const struct qstr *file_name, struct inode *inode, u32 cookie)
324464 {
465
+	const struct path *path = fsnotify_data_path(data, data_type);
325466 	struct fsnotify_iter_info iter_info = {};
326
-	struct mount *mnt;
467
+	struct super_block *sb;
468
+	struct mount *mnt = NULL;
469
+	struct inode *parent = NULL;
327470 	int ret = 0;
328
-	__u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
471
+	__u32 test_mask, marks_mask;
329472 
330
-	if (data_is == FSNOTIFY_EVENT_PATH)
331
-		mnt = real_mount(((const struct path *)data)->mnt);
332
-	else
333
-		mnt = NULL;
473
+	if (path)
474
+		mnt = real_mount(path->mnt);
334475 
335
-	/* An event "on child" is not intended for a mount mark */
336
-	if (mask & FS_EVENT_ON_CHILD)
337
-		mnt = NULL;
476
+	if (!inode) {
477
+		/* Dirent event - report on TYPE_INODE to dir */
478
+		inode = dir;
479
+	} else if (mask & FS_EVENT_ON_CHILD) {
480
+		/*
481
+		 * Event on child - report on TYPE_PARENT to dir if it is
482
+		 * watching children and on TYPE_INODE to child.
483
+		 */
484
+		parent = dir;
485
+	}
486
+	sb = inode->i_sb;
338487 
339488 	/*
340489 	 * Optimization: srcu_read_lock() has a memory barrier which can
....@@ -343,36 +492,54 @@
343492 	 * SRCU because we have no references to any objects and do not
344493 	 * need SRCU to keep them "alive".
345494 	 */
346
-	if (!to_tell->i_fsnotify_marks &&
347
-	    (!mnt || !mnt->mnt_fsnotify_marks))
495
+	if (!sb->s_fsnotify_marks &&
496
+	    (!mnt || !mnt->mnt_fsnotify_marks) &&
497
+	    (!inode || !inode->i_fsnotify_marks) &&
498
+	    (!parent || !parent->i_fsnotify_marks))
348499 		return 0;
500
+
501
+	marks_mask = sb->s_fsnotify_mask;
502
+	if (mnt)
503
+		marks_mask |= mnt->mnt_fsnotify_mask;
504
+	if (inode)
505
+		marks_mask |= inode->i_fsnotify_mask;
506
+	if (parent)
507
+		marks_mask |= parent->i_fsnotify_mask;
508
+
509
+
349510 	/*
350511 	 * if this is a modify event we may need to clear the ignored masks
351
-	 * otherwise return if neither the inode nor the vfsmount care about
352
-	 * this type of event.
512
+	 * otherwise return if none of the marks care about this type of event.
353513 	 */
354
-	if (!(mask & FS_MODIFY) &&
355
-	    !(test_mask & to_tell->i_fsnotify_mask) &&
356
-	    !(mnt && test_mask & mnt->mnt_fsnotify_mask))
514
+	test_mask = (mask & ALL_FSNOTIFY_EVENTS);
515
+	if (!(mask & FS_MODIFY) && !(test_mask & marks_mask))
357516 		return 0;
358517 
359518 	iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
360519 
361
-	iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] =
362
-		fsnotify_first_mark(&to_tell->i_fsnotify_marks);
520
+	iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] =
521
+		fsnotify_first_mark(&sb->s_fsnotify_marks);
363522 	if (mnt) {
364523 		iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] =
365524 			fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
366525 	}
526
+	if (inode) {
527
+		iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] =
528
+			fsnotify_first_mark(&inode->i_fsnotify_marks);
529
+	}
530
+	if (parent) {
531
+		iter_info.marks[FSNOTIFY_OBJ_TYPE_PARENT] =
532
+			fsnotify_first_mark(&parent->i_fsnotify_marks);
533
+	}
367534 
368535 	/*
369
-	 * We need to merge inode & vfsmount mark lists so that inode mark
370
-	 * ignore masks are properly reflected for mount mark notifications.
536
+	 * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark
537
+	 * ignore masks are properly reflected for mount/sb mark notifications.
371538 	 * That's why this traversal is so complicated...
372539 	 */
373540 	while (fsnotify_iter_select_report_types(&iter_info)) {
374
-		ret = send_to_group(to_tell, mask, data, data_is, cookie,
375
-				    file_name, &iter_info);
541
+		ret = send_to_group(mask, data, data_type, dir, file_name,
542
+				    cookie, &iter_info);
376543 
377544 		if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
378545 			goto out;
....@@ -387,13 +554,11 @@
387554 }
388555 EXPORT_SYMBOL_GPL(fsnotify);
389556 
390
-extern struct kmem_cache *fsnotify_mark_connector_cachep;
391
-
392557 static __init int fsnotify_init(void)
393558 {
394559 	int ret;
395560 
396
-	BUG_ON(hweight32(ALL_FSNOTIFY_BITS) != 23);
561
+	BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 25);
397562 
398563 	ret = init_srcu_struct(&fsnotify_mark_srcu);
399564 	if (ret)