[PATCH v2 5/5] fsnotify: send event type FSNOTIFY_EVENT_DENTRY to super block mark

[Amir Goldstein <amir73il@gmail.com>]

So far, existence of super block marks could be checked only on events
with data type FSNOTIFY_EVENT_PATH. Use d_sb field of dentry from events
with data type FSNOTIFY_EVENT_DENTRY to send event on super block mark.

This change has no effect on current backends. Soon, this will allow
fanotify backend to receive dentry events on a super block mark.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/notify/fsnotify.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 6a120b7f8b94..c9d673f0cbdc 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -338,6 +338,9 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
 		mnt = real_mount(((const struct path *)data)->mnt);
 		sb = mnt->mnt.mnt_sb;
 		mnt_or_sb_mask = mnt->mnt_fsnotify_mask | sb->s_fsnotify_mask;
+	} else if (data_is == FSNOTIFY_EVENT_DENTRY) {
+		sb = ((const struct dentry *)data)->d_sb;
+		mnt_or_sb_mask = sb->s_fsnotify_mask;
 	}
 	/* An event "on child" is not intended for a mount/sb mark */
 	if (mask & FS_EVENT_ON_CHILD)
@@ -350,8 +353,8 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
 	 * SRCU because we have no references to any objects and do not
 	 * need SRCU to keep them "alive".
 	 */
-	if (!to_tell->i_fsnotify_marks &&
-	    (!mnt || (!mnt->mnt_fsnotify_marks && !sb->s_fsnotify_marks)))
+	if (!to_tell->i_fsnotify_marks && (!mnt || !mnt->mnt_fsnotify_marks) &&
+	    (!sb || !sb->s_fsnotify_marks))
 		return 0;
 	/*
 	 * if this is a modify event we may need to clear the ignored masks
@@ -369,6 +372,8 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
 	if (mnt) {
 		iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] =
 			fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
+	}
+	if (sb) {
 		iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] =
 			fsnotify_first_mark(&sb->s_fsnotify_marks);
 	}
-- 
2.17.1