Btrfs: write barriers on commit, balance level before split

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

1 files changed, 11 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b666c3571aee..13046295bf7a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -540,6 +540,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         fs_info->btree_inode->i_nlink = 1;
         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
+        fs_info->do_barriers = 1;
         BTRFS_I(fs_info->btree_inode)->root = tree_root;
         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
                sizeof(struct btrfs_key));
@@ -622,6 +623,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root)
 {
+        int ret;
         struct buffer_head *bh = root->fs_info->sb_buffer;
 
         btrfs_set_super_root(root->fs_info->disk_super,
@@ -632,7 +634,15 @@ int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
         csum_tree_block(root, bh, 0);
         bh->b_end_io = end_buffer_write_sync;
         get_bh(bh);
-        submit_bh(WRITE, bh);
+        if (root->fs_info->do_barriers)
+                ret = submit_bh(WRITE_BARRIER, bh);
+        else
+                ret = submit_bh(WRITE, bh);
+        if (ret == -EOPNOTSUPP) {
+                set_buffer_uptodate(bh);
+                root->fs_info->do_barriers = 0;
+                ret = submit_bh(WRITE, bh);
+        }
         wait_on_buffer(bh);
         if (!buffer_uptodate(bh)) {
                 WARN_ON(1);