On Fri, Nov 18, 2022 at 01:14:08PM -0800, Catherine Hoang wrote:
> Add a new ioctl to retrieve the UUID of a mounted xfs filesystem. This is a
> precursor to adding the SETFSUUID ioctl.
>
> Signed-off-by: Catherine Hoang <catherine.hoang@xxxxxxxxxx>
> Reviewed-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
> ---
> fs/xfs/xfs_ioctl.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 1f783e979629..cf77715afe9e 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1865,6 +1865,39 @@ xfs_fs_eofblocks_from_user(
> return 0;
> }
>
> +static int
> +xfs_ioctl_getuuid(
> + struct xfs_mount *mp,
> + struct fsuuid __user *ufsuuid)
> +{
> + struct fsuuid fsuuid;
> + __u8 uuid[UUID_SIZE];
uuid_t, please, not an open coded uuid_t.
> +
> + if (copy_from_user(&fsuuid, ufsuuid, sizeof(fsuuid)))
> + return -EFAULT;
I still think this failing to copy the flex array member and then
having to declare a local uuid buffer is an ugly wart, not just on
the API side of things.
> + if (fsuuid.fsu_len == 0) {
> + fsuuid.fsu_len = UUID_SIZE;
XFS uses sizeof(uuid_t) for the size of it's uuids, not UUID_SIZE.
> + if (copy_to_user(&ufsuuid->fsu_len, &fsuuid.fsu_len,
> + sizeof(fsuuid.fsu_len)))
> + return -EFAULT;
> + return 0;
> + }
> +
> + if (fsuuid.fsu_len < UUID_SIZE || fsuuid.fsu_flags != 0)
> + return -EINVAL;
> +
> + spin_lock(&mp->m_sb_lock);
> + memcpy(uuid, &mp->m_sb.sb_uuid, UUID_SIZE);
> + spin_unlock(&mp->m_sb_lock);
Hmmmm. Shouldn't we be promoting xfs_fs_get_uuid() to xfs_super.c
(without the pNFS warning!) and calling that here, rather than open
coding another "get the XFS superblock UUID" function here?
i.e.
if (fsuuid.fsu_flags != 0)
return -EINVAL;
error = xfs_fs_get_uuid(&mp->m_sb, uuid, &fsuuid.fsu_len, NULL);
if (error)
return -EINVAL;
Also, uuid_copy()?
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
