From: Qu Wenruo wqu@suse.com
commit 604e6681e114d05a2e384c4d1e8ef81918037ef5 upstream.
Since the introduction of scrub interface, the only flag that we support is BTRFS_SCRUB_READONLY. Thus there is no sanity checks, if there are some undefined flags passed in, we just ignore them.
This is problematic if we want to introduce new scrub flags, as we have no way to determine if such flags are supported.
Address the problem by introducing a check for the flags, and if unsupported flags are set, return -EOPNOTSUPP to inform the user space.
This check should be backported for all supported kernels before any new scrub flags are introduced.
CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/ioctl.c | 5 +++++ include/uapi/linux/btrfs.h | 1 + 2 files changed, 6 insertions(+)
--- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4050,6 +4050,11 @@ static long btrfs_ioctl_scrub(struct fil if (IS_ERR(sa)) return PTR_ERR(sa);
+ if (sa->flags & ~BTRFS_SCRUB_SUPPORTED_FLAGS) { + ret = -EOPNOTSUPP; + goto out; + } + if (!(sa->flags & BTRFS_SCRUB_READONLY)) { ret = mnt_want_write_file(file); if (ret) --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -181,6 +181,7 @@ struct btrfs_scrub_progress { };
#define BTRFS_SCRUB_READONLY 1 +#define BTRFS_SCRUB_SUPPORTED_FLAGS (BTRFS_SCRUB_READONLY) struct btrfs_ioctl_scrub_args { __u64 devid; /* in */ __u64 start; /* in */