Btrfs: eliminate the exceptional root_tree refs=0
The fact that btrfs_root_refs() returned 0 for the tree_root caused
bugs in the past, therefore it is set to 1 with this patch and
(hopefully) all affected code is adapted to this change.
I verified this change by temporarily adding WARN_ON() checks
everywhere where btrfs_root_refs() is used, checking whether the
logic of the code is changed by btrfs_root_refs() returning 1
instead of 0 for root->root_key.objectid == BTRFS_ROOT_TREE_OBJECTID.
With these added checks, I ran the xfstests './check -g auto'.
The two roots chunk_root and log_root_tree that are only referenced
by the superblock and the log_roots below the log_root_tree still
have btrfs_root_refs() == 0, only the tree_root is changed.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 2c66ddb..d11e1c6 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -412,8 +412,7 @@
return 0;
/* Don't save inode cache if we are deleting this root */
- if (btrfs_root_refs(&root->root_item) == 0 &&
- root != root->fs_info->tree_root)
+ if (btrfs_root_refs(&root->root_item) == 0)
return 0;
if (!btrfs_test_opt(root, INODE_MAP_CACHE))