Btrfs: Add data=ordered support

This forces file data extents down the disk along with the metadata that
references them.  The current implementation is fairly simple, and just
writes out all of the dirty pages in an inode before the commit.

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

1 files changed, 15 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a6170ff19e7f..34cf1f1f47be 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -406,7 +406,6 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
         init_completion(&root->kobj_unregister);
-        init_rwsem(&root->snap_sem);
         root->defrag_running = 0;
         root->defrag_level = 0;
         root->root_key.objectid = objectid;
@@ -498,6 +497,21 @@ insert:
         return root;
 }
 
+struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
+                                        u64 root_objectid)
+{
+        struct btrfs_root *root;
+
+        if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
+                return fs_info->tree_root;
+        if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
+                return fs_info->extent_root;
+
+        root = radix_tree_lookup(&fs_info->fs_roots_radix,
+                                 (unsigned long)root_objectid);
+        return root;
+}
+
 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
                                               struct btrfs_key *location)
 {