fsnotify: take inode->i_lock inside fsnotify_find_mark_entry()

All callers to fsnotify_find_mark_entry() except one take and
release inode->i_lock around the call.  Take the lock inside
fsnotify_find_mark_entry() instead.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>

4 files changed, 19 insertions, 25 deletions

diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index 3efb8b9a572d..cac2eb896639 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -95,11 +95,7 @@ static int dnotify_handle_event(struct fsnotify_group *group,
 
 	to_tell = event->to_tell;
 
-	spin_lock(&to_tell->i_lock);
 	fsn_mark = fsnotify_find_mark(group, to_tell);
-	spin_unlock(&to_tell->i_lock);
-
-	/* unlikely since we alreay passed dnotify_should_send_event() */
 	if (unlikely(!fsn_mark))
 		return 0;
 	dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
@@ -147,11 +143,7 @@ static bool dnotify_should_send_event(struct fsnotify_group *group,
 	if (!S_ISDIR(inode->i_mode))
 		return false;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
-
-	/* no mark means no dnotify watch */
 	if (!fsn_mark)
 		return false;
 
@@ -201,9 +193,7 @@ void dnotify_flush(struct file *filp, fl_owner_t id)
 	if (!S_ISDIR(inode->i_mode))
 		return;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(dnotify_group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!fsn_mark)
 		return;
 	dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
@@ -356,9 +346,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
 	mutex_lock(&dnotify_mark_mutex);
 
 	/* add the new_fsn_mark or find an old one. */
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(dnotify_group, inode);
-	spin_unlock(&inode->i_lock);
 	if (fsn_mark) {
 		dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
 		spin_lock(&fsn_mark->lock);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 27c1b43ad739..ba6f9833561b 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -261,12 +261,8 @@ void fsnotify_clear_marks_by_inode(struct inode *inode)
 	}
 }
 
-/*
- * given a group and inode, find the mark associated with that combination.
- * if found take a reference to that mark and return it, else return NULL
- */
-struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group,
-					 struct inode *inode)
+static struct fsnotify_mark *fsnotify_find_mark_locked(struct fsnotify_group *group,
+						       struct inode *inode)
 {
 	struct fsnotify_mark *mark;
 	struct hlist_node *pos;
@@ -282,6 +278,22 @@ struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group,
 	return NULL;
 }
 
+/*
+ * given a group and inode, find the mark associated with that combination.
+ * if found take a reference to that mark and return it, else return NULL
+ */
+struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group,
+					 struct inode *inode)
+{
+	struct fsnotify_mark *mark;
+
+	spin_lock(&inode->i_lock);
+	mark = fsnotify_find_mark_locked(group, inode);
+	spin_unlock(&inode->i_lock);
+
+	return mark;
+}
+
 void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old)
 {
 	assert_spin_locked(&old->lock);
@@ -349,7 +361,7 @@ int fsnotify_add_mark(struct fsnotify_mark *mark,
 	spin_lock(&inode->i_lock);
 
 	if (!allow_dups)
-		lmark = fsnotify_find_mark(group, inode);
+		lmark = fsnotify_find_mark_locked(group, inode);
 	if (!lmark) {
 		mark->group = group;
 		mark->i.inode = inode;
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 12dc72be992e..cc8f6bcbb4a3 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -97,9 +97,7 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev
 
 	to_tell = event->to_tell;
 
-	spin_lock(&to_tell->i_lock);
 	fsn_mark = fsnotify_find_mark(group, to_tell);
-	spin_unlock(&to_tell->i_lock);
 	/* race with watch removal?  We already passes should_send */
 	if (unlikely(!fsn_mark))
 		return 0;
@@ -147,9 +145,7 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode
 	struct fsnotify_mark *fsn_mark;
 	bool send;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!fsn_mark)
 		return false;
 
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index 80d102acb86b..ad5a1ea7827e 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -566,9 +566,7 @@ static int inotify_update_existing_watch(struct fsnotify_group *group,
 	if (unlikely(!mask))
 		return -EINVAL;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!fsn_mark)
 		return -ENOENT;