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;