btrfs: clear oneshot options on mount and remount

Some options only apply during mount time and are cleared at the end
of mount. For now, the example is USEBACKUPROOT, but CLEAR_CACHE also
fits the bill, and this is a preparation patch for also clearing that
option.

One subtlety is that the current code only resets USEBACKUPROOT on rw
mounts, but the option is meaningfully "consumed" by a ro mount, so it
feels appropriate to clear in that case as well. A subsequent read-write
remount would not go through open_ctree, which is the only place that
checks the option, so the change should be benign.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 49b4a16488c9..93514555453b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1999,6 +1999,7 @@ out:
 
 	wake_up_process(fs_info->transaction_kthread);
 	btrfs_remount_cleanup(fs_info, old_opts);
+	btrfs_clear_oneshot_options(fs_info);
 	clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
 
 	return 0;