Btrfs: add a recovery_errors mount option to limp along with a corrupted FS

When btrfs isn't able to read a tree root, it generally aborts the
mount.  This patch adds mount -o recovery_errors to force it to
try and continue along.

Right now it only deals with corrupt csum roots, but it will also
gain support for extent allocation tree roots as well.  In this mode,
the FS is forced readonly and we ignore all csums.

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