Re: [PATCH v2 6/8] linux-user: Add support for two btrfs ioctls used for subvolume

[Laurent Vivier]

Le 03/08/2020 à 11:46, Filip Bozuta a écrit :
> This patch implements functionality for following ioctl:
> 
> BTRFS_IOC_DEFAULT_SUBVOL - Setting a default subvolume
> 
>     Set a default subvolume for a btrfs filesystem. The third
>     ioctl's argument is a '__u64' (unsigned long long) which
>     represents the id of a subvolume that is to be set as
>     the default.
> 
> BTRFS_IOC_GET_SUBVOL_ROOTREF - Getting tree and directory id of subvolumes
> 
>     Read tree and directory id of subvolumes from a btrfs
>     filesystem. The tree and directory id's are returned in the
>     ioctl's third argument which represents a pointer to a
>     following type:
> 
>     struct btrfs_ioctl_get_subvol_rootref_args {
>               /* in/out, minimum id of rootref's treeid to be searched */
>               __u64 min_treeid;
> 
>               /* out */
>               struct {
>                       __u64 treeid;
>                       __u64 dirid;
>               } rootref[BTRFS_MAX_ROOTREF_BUFFER_NUM];
> 
>               /* out, number of found items */
>               __u8 num_items;
>               __u8 align[7];
>      };
> 
>      Before calling this ioctl, 'min_treeid' field should be filled
>      with value that represent the minimum value for the tree id.
> 
> Implementation notes:
> 
>     Ioctl BTRFS_IOC_GET_SUBVOL_ROOTREF uses the above mentioned structure
>     type as third argument. That is the reason why a aproppriate thunk
>     structure definition is added in file 'syscall_types.h'.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  linux-user/ioctls.h        |  7 +++++++
>  linux-user/syscall_defs.h  |  3 +++
>  linux-user/syscall_types.h | 11 +++++++++++
>  3 files changed, 21 insertions(+)
> 
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index a7f5664487..2c553103e6 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -206,6 +206,9 @@
>       IOCTL(BTRFS_IOC_INO_LOOKUP, IOC_RW,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_ino_lookup_args)))
>  #endif
> +#ifdef BTRFS_IOC_DEFAULT_SUBVOL
> +     IOCTL(BTRFS_IOC_DEFAULT_SUBVOL, IOC_W, MK_PTR(TYPE_ULONGLONG))
> +#endif
>  #ifdef BTRFS_IOC_SUBVOL_GETFLAGS
>       IOCTL(BTRFS_IOC_SUBVOL_GETFLAGS, IOC_R, MK_PTR(TYPE_ULONGLONG))
>  #endif
> @@ -248,6 +251,10 @@
>       IOCTL(BTRFS_IOC_GET_SUBVOL_INFO, IOC_R,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_subvol_info_args)))
>  #endif
> +#ifdef BTRFS_IOC_GET_SUBVOL_ROOTREF
> +     IOCTL(BTRFS_IOC_GET_SUBVOL_ROOTREF, IOC_RW,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_subvol_rootref_args)))
> +#endif
>  #ifdef BTRFS_IOC_INO_LOOKUP_USER
>       IOCTL(BTRFS_IOC_INO_LOOKUP_USER, IOC_RW,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_ino_lookup_user_args)))
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 538b884b8f..f1718ac521 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -976,6 +976,8 @@ struct target_rtc_pll_info {
>  #define TARGET_BTRFS_IOC_SUBVOL_CREATE          
> TARGET_IOWU(BTRFS_IOCTL_MAGIC, 14)
>  #define TARGET_BTRFS_IOC_SNAP_DESTROY           
> TARGET_IOWU(BTRFS_IOCTL_MAGIC, 15)
>  #define TARGET_BTRFS_IOC_INO_LOOKUP             
> TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 18)
> +#define TARGET_BTRFS_IOC_DEFAULT_SUBVOL         
> TARGET_IOW(BTRFS_IOCTL_MAGIC, 19,\
> +                                                           abi_ullong)
>  #define TARGET_BTRFS_IOC_SUBVOL_GETFLAGS        
> TARGET_IOR(BTRFS_IOCTL_MAGIC, 25,\
>                                                             abi_ullong)
>  #define TARGET_BTRFS_IOC_SUBVOL_SETFLAGS        
> TARGET_IOW(BTRFS_IOCTL_MAGIC, 26,\
> @@ -989,6 +991,7 @@ struct target_rtc_pll_info {
>  #define TARGET_BTRFS_IOC_GET_SUPPORTED_FEATURES 
> TARGET_IORU(BTRFS_IOCTL_MAGIC, 57)
>  #define TARGET_BTRFS_IOC_LOGICAL_INO_V2         
> TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 59)
>  #define TARGET_BTRFS_IOC_GET_SUBVOL_INFO        
> TARGET_IORU(BTRFS_IOCTL_MAGIC, 60)
> +#define TARGET_BTRFS_IOC_GET_SUBVOL_ROOTREF     
> TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 61)
>  #define TARGET_BTRFS_IOC_INO_LOOKUP_USER        
> TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 62)
>  
>  /* usb ioctls */
> diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
> index 978f2d682c..6bac8f46bb 100644
> --- a/linux-user/syscall_types.h
> +++ b/linux-user/syscall_types.h
> @@ -381,6 +381,17 @@ STRUCT(btrfs_ioctl_dev_info_args,
>         MK_ARRAY(TYPE_ULONGLONG, 379), /* unused */
>         MK_ARRAY(TYPE_CHAR, BTRFS_DEVICE_PATH_NAME_MAX)) /* path */
>  
> +STRUCT(rootref,
> +       TYPE_ULONGLONG, /* treeid */
> +       TYPE_ULONGLONG) /* dirid */
> +
> +STRUCT(btrfs_ioctl_get_subvol_rootref_args,
> +       TYPE_ULONGLONG, /* min_treeid */
> +       MK_ARRAY(MK_STRUCT(STRUCT_rootref),
> +                BTRFS_MAX_ROOTREF_BUFFER_NUM), /* rootref */
> +       TYPE_CHAR, /* num_items */
> +       MK_ARRAY(TYPE_CHAR, 7)) /* align */
> +
>  STRUCT(btrfs_ioctl_get_dev_stats,
>         TYPE_ULONGLONG, /* devid */
>         TYPE_ULONGLONG, /* nr_items */
> 

Applied to my linux-user-for-5.2 branch.

Thanks,
Laurent