fsnotify: Move locking into fsnotify_recalc_mask()

Move locking of locks protecting a list of marks into
fsnotify_recalc_mask(). This reduces code churn in the following patch
which changes the lock protecting the list of marks.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

5 files changed, 37 insertions, 40 deletions

diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index 5024729dba23..41b2a070761c 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -69,8 +69,7 @@ static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark)
         if (old_mask == new_mask)
                 return;
 
-        if (fsn_mark->connector)
-                fsnotify_recalc_inode_mask(fsn_mark->connector->inode);
+        fsnotify_recalc_mask(fsn_mark->connector);
 }
 
 /*
diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index 0354338aad78..96051780d50e 100644
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -14,9 +14,6 @@ extern void fsnotify_flush_notify(struct fsnotify_group *group);
 /* protects reads of inode and vfsmount marks list */
 extern struct srcu_struct fsnotify_mark_srcu;
 
-/* Calculate mask of events for a list of marks */
-extern u32 fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
-
 /* compare two groups for sorting of marks lists */
 extern int fsnotify_compare_groups(struct fsnotify_group *a,
                                    struct fsnotify_group *b);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 87bef7d802db..9b2f4e6eb8eb 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -30,17 +30,9 @@
 
 #include "../internal.h"
 
-/*
- * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types
- * any notifier is interested in hearing for this inode.
- */
 void fsnotify_recalc_inode_mask(struct inode *inode)
 {
-        spin_lock(&inode->i_lock);
-        inode->i_fsnotify_mask = fsnotify_recalc_mask(inode->i_fsnotify_marks);
-        spin_unlock(&inode->i_lock);
-
-        __fsnotify_update_child_dentry_flags(inode);
+        fsnotify_recalc_mask(inode->i_fsnotify_marks);
 }
 
 struct inode *fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
@@ -57,14 +49,10 @@ struct inode *fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
         empty = hlist_empty(&mark->connector->list);
         mark->connector = NULL;
 
-        /*
-         * this mark is now off the inode->i_fsnotify_marks list and we
-         * hold the inode->i_lock, so this is the perfect time to update the
-         * inode->i_fsnotify_mask
-         */
-        inode->i_fsnotify_mask = fsnotify_recalc_mask(inode->i_fsnotify_marks);
         spin_unlock(&inode->i_lock);
 
+        fsnotify_recalc_mask(inode->i_fsnotify_marks);
+
         return empty ? inode : NULL;
 }
 
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index b3f83ed6e8be..06faf166c7ae 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -105,18 +105,40 @@ void fsnotify_put_mark(struct fsnotify_mark *mark)
         }
 }
 
-/* Calculate mask of events for a list of marks */
-u32 fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
+static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
 {
         u32 new_mask = 0;
         struct fsnotify_mark *mark;
 
-        if (!conn)
-                return 0;
-
         hlist_for_each_entry(mark, &conn->list, obj_list)
                 new_mask |= mark->mask;
-        return new_mask;
+        if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+                conn->inode->i_fsnotify_mask = new_mask;
+        else if (conn->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT)
+                real_mount(conn->mnt)->mnt_fsnotify_mask = new_mask;
+}
+
+/*
+ * Calculate mask of events for a list of marks. The caller must make sure
+ * connector cannot disappear under us (usually by holding a mark->lock or
+ * mark->group->mark_mutex for a mark on this list).
+ */
+void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
+{
+        if (!conn)
+                return;
+
+        if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+                spin_lock(&conn->inode->i_lock);
+        else
+                spin_lock(&conn->mnt->mnt_root->d_lock);
+        __fsnotify_recalc_mask(conn);
+        if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE) {
+                spin_unlock(&conn->inode->i_lock);
+                __fsnotify_update_child_dentry_flags(conn->inode);
+        } else {
+                spin_unlock(&conn->mnt->mnt_root->d_lock);
+        }
 }
 
 /*
@@ -423,10 +445,8 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
         if (ret)
                 goto err;
 
-        if (inode)
-                fsnotify_recalc_inode_mask(inode);
-        else
-                fsnotify_recalc_vfsmount_mask(mnt);
+        if (mark->mask)
+                fsnotify_recalc_mask(mark->connector);
 
         return ret;
 err:
diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c
index 49ccbdb74f82..ffe0d7098cba 100644
--- a/fs/notify/vfsmount_mark.c
+++ b/fs/notify/vfsmount_mark.c
@@ -34,17 +34,9 @@ void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
         fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT);
 }
 
-/*
- * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
- * any notifier is interested in hearing for this mount point
- */
 void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
 {
-        struct mount *m = real_mount(mnt);
-
-        spin_lock(&mnt->mnt_root->d_lock);
-        m->mnt_fsnotify_mask = fsnotify_recalc_mask(m->mnt_fsnotify_marks);
-        spin_unlock(&mnt->mnt_root->d_lock);
+        fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks);
 }
 
 void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
@@ -60,8 +52,9 @@ void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
         hlist_del_init_rcu(&mark->obj_list);
         mark->connector = NULL;
 
-        m->mnt_fsnotify_mask = fsnotify_recalc_mask(m->mnt_fsnotify_marks);
         spin_unlock(&mnt->mnt_root->d_lock);
+
+        fsnotify_recalc_mask(m->mnt_fsnotify_marks);
 }
 
 /*