linux-kernel - [PATCH 4.19 063/110] fsnotify: generalize handling of extra event flags

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Date:   Thu, 29 Nov 2018 15:12:34 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Amir Goldstein <amir73il@...il.com>,
        Jan Kara <jack@...e.cz>
Subject: [PATCH 4.19 063/110] fsnotify: generalize handling of extra event flags

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Amir Goldstein <amir73il@...il.com>

commit 007d1e8395eaa59b0e7ad9eb2b53a40859446a88 upstream.

FS_EVENT_ON_CHILD gets a special treatment in fsnotify() because it is
not a flag specifying an event type, but rather an extra flags that may
be reported along with another event and control the handling of the
event by the backend.

FS_ISDIR is also an "extra flag" and not an "event type" and therefore
desrves the same treatment. With inotify/dnotify backends it was never
possible to set FS_ISDIR in mark masks, so it did not matter.
With fanotify backend, mark adding code jumps through hoops to avoid
setting the FS_ISDIR in the commulative object mask.

Separate the constant ALL_FSNOTIFY_EVENTS to ALL_FSNOTIFY_FLAGS and
ALL_FSNOTIFY_EVENTS, so the latter can be used to test for specific
event types.

Signed-off-by: Amir Goldstein <amir73il@...il.com>
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/notify/fsnotify.c             |    7 +++----
 include/linux/fsnotify_backend.h |    9 +++++++--
 2 files changed, 10 insertions(+), 6 deletions(-)

--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -193,7 +193,7 @@ static int send_to_group(struct inode *t
 			 struct fsnotify_iter_info *iter_info)
 {
 	struct fsnotify_group *group = NULL;
-	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
+	__u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
 	__u32 marks_mask = 0;
 	__u32 marks_ignored_mask = 0;
 	struct fsnotify_mark *mark;
@@ -324,8 +324,7 @@ int fsnotify(struct inode *to_tell, __u3
 	struct fsnotify_iter_info iter_info = {};
 	struct mount *mnt;
 	int ret = 0;
-	/* global tests shouldn't care about events on child only the specific event */
-	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
+	__u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
 
 	if (data_is == FSNOTIFY_EVENT_PATH)
 		mnt = real_mount(((const struct path *)data)->mnt);
@@ -389,7 +388,7 @@ static __init int fsnotify_init(void)
 {
 	int ret;
 
-	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
+	BUG_ON(hweight32(ALL_FSNOTIFY_BITS) != 23);
 
 	ret = init_srcu_struct(&fsnotify_mark_srcu);
 	if (ret)
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -68,15 +68,20 @@
 
 #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
 
+/* Events that can be reported to backends */
 #define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
 			     FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
 			     FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
 			     FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
 			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
-			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
-			     FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
+			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME)
+
+/* Extra flags that may be reported with event or control handling of events */
+#define ALL_FSNOTIFY_FLAGS  (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \
 			     FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
 
+#define ALL_FSNOTIFY_BITS   (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS)
+
 struct fsnotify_group;
 struct fsnotify_event;
 struct fsnotify_mark;