Btrfs: disallow 'btrfs {balance,replace} cancel' on ro mounts
For both balance and replace, cancelling involves changing the on-disk
state and committing a transaction, which is not a good thing to do on
read-only filesystems.
Cc: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9dfe038..5d7ea26 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3424,6 +3424,9 @@
int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
{
+ if (fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
+
mutex_lock(&fs_info->balance_mutex);
if (!fs_info->balance_ctl) {
mutex_unlock(&fs_info->balance_mutex);