dquot: move dquot drop responsibility into the filesystem

Currently clear_inode calls vfs_dq_drop directly.  This means
we tie the quota code into the VFS.  Get rid of that and make the
filesystem responsible for the drop inside the ->clear_inode
superblock operation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/super.c

@@ -194,6 +194,8 @@ static void destroy_inodecache(void)
 static void ext2_clear_inode(struct inode *inode)
 {
 	struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
+
+	vfs_dq_drop(inode);
 	ext2_discard_reservation(inode);
 	EXT2_I(inode)->i_block_alloc_info = NULL;
 	if (unlikely(rsv))