Re: [PATCH 4/4] linux-user: Add support for a group of btrfs ioctls used to get/set features

[Laurent Vivier]

Le 09/07/2020 à 17:52, Filip Bozuta a écrit :
> This patch implements functionality for following ioctls:
> 
> BTRFS_IOC_GET_FEATURES - Getting feature flags
> 
>     Read feature flags for a btrfs filesystem. The feature flags
>     are returned inside the ioctl's third argument which represents
>     a pointer to a following structure type:
> 
>     struct btrfs_ioctl_feature_flags {
>       __u64 compat_flags;
>       __u64 compat_ro_flags;
>       __u64 incompat_flags;
>     };
> 
>     All of the structure field represent bit masks that can be composed
>     of values which can be found on:
>     https://elixir.bootlin.com/linux/latest/source/fs/btrfs/ctree.h#L282
> 
> BTRFS_IOC_SET_FEATURES - Setting feature flags
> 
>     Set and clear feature flags for a btrfs filesystem. The feature flags
>     are set using the ioctl's third argument which represents a
>     'struct btrfs_ioctl_feature_flags[2]' array. The first element of the
>     array represent flags which are to be cleared and the second element of
>     the array represent flags which are to be set. The second element has the
>     priority over the first, which means that if there are matching flags
>     in the elements, they will be set in the filesystem. If the flag values
>     in the third argument aren't correctly set to be composed of the available
>     predefined flag values, errno ENOPERM ("Operation not permitted") is 
> returned.
> 
> BTRFS_IOC_GET_SUPPORTED_FEATURES - Getting supported feature flags
> 
>     Read supported feature flags for a btrfs filesystem. The supported
>     feature flags are read using the ioctl's third argument which represents
>     a 'struct btrfs_ioctl_feature_flags[3]' array. The first element of this
>     array represents all of the supported flags in the btrfs filesystem.
>     The second element represents flags that can be safely set and third 
> element
>     represent flags that can be safely clearead.
> 
> Implementation notes:
> 
>     All of the implemented ioctls use 'struct btrfs_ioctl_feature_flags' as
>     third argument. That is the reason why a corresponding defintion was added
>     in file 'linux-user/syscall_types.h'.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/ioctls.h        | 12 ++++++++++++
>  linux-user/syscall_defs.h  |  6 ++++++
>  linux-user/syscall_types.h |  5 +++++
>  3 files changed, 23 insertions(+)
> 
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index c20bd97736..c6303a0406 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -216,6 +216,18 @@
>       IOCTL(BTRFS_IOC_GET_DEV_STATS, IOC_RW,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_dev_stats)))
>  #endif
> +#ifdef BTRFS_IOC_GET_FEATURES
> +     IOCTL(BTRFS_IOC_GET_FEATURES, IOC_R,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_feature_flags)))
> +#endif
> +#ifdef BTRFS_IOC_SET_FEATURES
> +     IOCTL(BTRFS_IOC_SET_FEATURES, IOC_W,
> +           MK_PTR(MK_ARRAY(MK_STRUCT(STRUCT_btrfs_ioctl_feature_flags), 2)))
> +#endif
> +#ifdef BTRFS_IOC_GET_SUPPORTED_FEATURES
> +     IOCTL(BTRFS_IOC_GET_SUPPORTED_FEATURES, IOC_R,
> +           MK_PTR(MK_ARRAY(MK_STRUCT(STRUCT_btrfs_ioctl_feature_flags), 3)))
> +#endif
>  #ifdef BTRFS_IOC_GET_SUBVOL_INFO
>       IOCTL(BTRFS_IOC_GET_SUBVOL_INFO, IOC_R,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_subvol_info_args)))
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 20c03cd145..9db6f46cba 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -990,6 +990,12 @@ struct target_rtc_pll_info {
>                                            30, struct 
> btrfs_ioctl_dev_info_args)
>  #define TARGET_BTRFS_IOC_GET_DEV_STATS          
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
>                                            52, struct 
> btrfs_ioctl_get_dev_stats)
> +#define TARGET_BTRFS_IOC_GET_FEATURES           
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> +                                         57, struct 
> btrfs_ioctl_feature_flags)
> +#define TARGET_BTRFS_IOC_SET_FEATURES           
> TARGET_IOW(BTRFS_IOCTL_MAGIC, \
> +                                       57, struct 
> btrfs_ioctl_feature_flags[2])
> +#define TARGET_BTRFS_IOC_GET_SUPPORTED_FEATURES 
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> +                                       57, struct 
> btrfs_ioctl_feature_flags[3])
>  #define TARGET_BTRFS_IOC_GET_SUBVOL_INFO        
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
>                                     60, struct 
> btrfs_ioctl_get_subvol_info_args)

TARGET_IORU() and TARGET_IOWU()

with that changed:

Reviewed-by: Laurent Vivier <laurent@vivier.eu>

Thanks,
Laurent