Btrfs: very minimal locking

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 17 insertions, 9 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index a2db05594695..0ca1080e0198 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -453,25 +453,21 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         struct inode *inode;
         int err;
 
+        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         inode = btrfs_new_inode(trans, dir, mode);
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
-                return err;
+                goto out_unlock;
         // FIXME mark the inode dirty
         err = btrfs_add_nondir(trans, dentry, inode);
         dir->i_sb->s_dirt = 1;
         btrfs_end_transaction(trans, root);
+out_unlock:
+        mutex_unlock(&root->fs_info->fs_mutex);
         return err;
 }
 
-static void btrfs_write_super(struct super_block *sb)
-{
-        sb->s_dirt = 0;
-printk("btrfs write_super!\n");
-        filemap_flush(sb->s_bdev->bd_inode->i_mapping);
-}
-
 static int btrfs_sync_fs(struct super_block *sb, int wait)
 {
         struct btrfs_trans_handle *trans;
@@ -479,17 +475,29 @@ static int btrfs_sync_fs(struct super_block *sb, int wait)
         int ret;
 
         sb->s_dirt = 0;
-        return 0;
+        if (!wait) {
+                filemap_flush(sb->s_bdev->bd_inode->i_mapping);
+                return 0;
+        }
+        filemap_write_and_wait(sb->s_bdev->bd_inode->i_mapping);
 
         root = btrfs_sb(sb);
+        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         ret = btrfs_commit_transaction(trans, root);
         sb->s_dirt = 0;
         BUG_ON(ret);
 printk("btrfs sync_fs\n");
+        mutex_unlock(&root->fs_info->fs_mutex);
         return 0;
 }
 
+static void btrfs_write_super(struct super_block *sb)
+{
+        btrfs_sync_fs(sb, 1);
+}
+
+
 static int btrfs_get_sb(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {