Re: [PATCH] btrfs: relocation: Remove is_cowonly_root()

[Josef Bacik <josef@toxicpanda.com>]

On 2/12/20 2:43 AM, Qu Wenruo wrote:
> This function is only used in read_fs_root(), which is just a wrapper of
> btrfs_get_fs_root().
> 
> For all the mentioned essential roots except log root tree,
> btrfs_get_fs_root() has its own quick path to grab them from fs_info
> directly, thus no need for key.offset modification.
> 
> For subvolume trees, btrfs_get_fs_root() with key.offset == -1 is
> completely fine.
> 
> For log trees and log root tree, it's impossible to hit them, as for
> relocation all backrefs are fetched from commit root, which never
> records log tree blocks.
> 
> Log tree blocks either get freed in regular transaction commit, or
> replayed at mount time. At runtime we should never hit an backref for
> log tree in extent tree.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef