->write_super lock_super pushdown

Push down lock_super into ->write_super instances and remove it from the
caller.

Following filesystem don't need ->s_lock in ->write_super and are skipped:

 * bfs, nilfs2 - no other uses of s_lock and have internal locks in
	->write_super
 * ext2 - uses BKL in ext2_write_super and has internal calls without s_lock
 * reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in
 	->write_super
 * xfs - no other uses of s_lock and uses internal lock (buffer lock on
	superblock buffer) to serialize ->write_super.  Also xfs_fs_write_super
	is superflous and will go away in the next merge window

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a9c683425929..c17200a42301 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -579,7 +579,7 @@ static void ext4_put_super(struct super_block *sb)
         lock_super(sb);
         lock_kernel();
         if (sb->s_dirt)
-                ext4_write_super(sb);
+                ext4_commit_super(sb, 1);
 
         ext4_release_system_zone(sb);
         ext4_mb_release(sb);
@@ -3336,7 +3336,9 @@ int ext4_force_commit(struct super_block *sb)
 
 static void ext4_write_super(struct super_block *sb)
 {
+        lock_super(sb);
         ext4_commit_super(sb, 1);
+        unlock_super(sb);
 }
 
 static int ext4_sync_fs(struct super_block *sb, int wait)