On Tue, Jul 19, 2022 at 8:55 AM Jeremy Bongio <bongiojp@xxxxxxxxx> wrote:
>
> This fixes a race between changing the ext4 superblock uuid and operations
> like mounting, resizing, changing features, etc.
>
> Reviewed-by: Theodore Ts'o <tytso@xxxxxxx>
> Signed-off-by: Jeremy Bongio <bongiojp@xxxxxxxxx>
> ---
>
> This pair of ioctls may be implemented in more filesystems in the future,
> namely XFS.
>
> +++ b/fs/ext4/ext4.h
> @@ -724,6 +724,8 @@ enum {
> #define EXT4_IOC_GETSTATE _IOW('f', 41, __u32)
> #define EXT4_IOC_GET_ES_CACHE _IOWR('f', 42, struct fiemap)
> #define EXT4_IOC_CHECKPOINT _IOW('f', 43, __u32)
> +#define EXT4_IOC_GETFSUUID _IOR('f', 44, struct fsuuid)
> +#define EXT4_IOC_SETFSUUID _IOW('f', 44, struct fsuuid)
The implementation looks good to me, but maybe it should be defined in
the UAPI headers in a filesystem-independent way? Having it in a private
header means it will not be available to portable user programs, and will
be hidden from tools like strace that parse the uapi headers to find
ioctl definitions.
Arnd
