Re: [PATCH v2 3/4] linux-user: Add support for btrfs ioctls used to manage quota

[Laurent Vivier <laurent@vivier.eu>]

Le 17/07/2020 à 16:44, Filip Bozuta a écrit :
> This patch implements functionality for following ioctls:
> 
> BTRFS_IOC_QUOTA_CTL - Enabling/Disabling quota support
> 
>     Enable or disable quota support for a btrfs filesystem. Quota
>     support is enabled or disabled using the ioctls third argument
>     which represents a pointer to a following type:
> 
>     struct btrfs_ioctl_quota_ctl_args {
> 	__u64 cmd;
> 	__u64 status;
>     };
> 
>     Before calling this ioctl, the 'cmd' field should be filled
>     with one of the values 'BTRFS_QUOTA_CTL_ENABLE' (enabling quota)
>     'BTRFS_QUOTA_CTL_DISABLE' (disabling quota).
> 
> BTRFS_IOC_QGROUP_CREATE - Creating/Removing a subvolume quota group
> 
>     Create or remove a subvolume quota group. The subvolume quota
>     group is created or removed using the ioctl's third argument which
>     represents a pointer to a following type:
> 
>     struct btrfs_ioctl_qgroup_create_args {
> 	__u64 create;
> 	__u64 qgroupid;
>     };
> 
>     Before calling this ioctl, the 'create' field should be filled
>     with the aproppriate value depending on if the user wants to
>     create or remove a quota group (0 for removing, everything else
>     for creating). Also, the 'qgroupid' field should be filled with
>     the value for the quota group id that is to be created.
> 
> BTRFS_IOC_QGROUP_ASSIGN - Asigning or removing a quota group as child group
> 
>     Asign or remove a quota group as child quota group of another
>     group in the btrfs filesystem. The asignment is done using the
>     ioctl's third argument which represents a pointert to a following type:
> 
>     struct btrfs_ioctl_qgroup_assign_args {
> 	__u64 assign;
> 	__u64 src;
> 	__u64 dst;
>     };
> 
>     Before calling this ioctl, the 'assign' field should be filled with
>     the aproppriate value depending on if the user wants to asign or remove
>     a quota group as a child quota group of another group (0 for removing,
>     everythin else for asigning). Also, the 'src' and 'dst' fields should
>     be filled with the aproppriate quota group id values depending on which
>     quota group needs to asigned or removed as child quota group of another
>     group ('src' gets asigned or removed as child group of 'dst').
> 
> BTRFS_IOC_QGROUP_LIMIT - Limiting the size of a quota group
> 
>     Limit the size of a quota group. The size of the quota group is limited
>     with the ioctls third argument which represents a pointer to a following
>     type:
> 
>     struct btrfs_ioctl_qgroup_limit_args {
> 	__u64	qgroupid;
> 	struct btrfs_qgroup_limit lim;
>     };
> 
>     Before calling this ioctl, the 'qgroup' id field should be filled with
>     aproppriate value of the quota group id for which the size is to be
>     limited. The second field is of following type:
> 
>     struct btrfs_qgroup_limit {
> 	__u64	flags;
> 	__u64	max_rfer;
> 	__u64	max_excl;
> 	__u64	rsv_rfer;
> 	__u64	rsv_excl;
>     };
> 
>     The 'max_rfer' field should be filled with the size to which the quota
>     group should be limited. The 'flags' field can be used for passing
>     additional options and can have values which can be found on:
>     https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/btrfs.h#L67
> 
> BTRFS_IOC_QUOTA_RESCAN_STATUS - Checking status of running rescan operation
> 
>     Check status of a running rescan operation. The status is checked using
>     the ioctl's third argument which represents a pointer to a following type:
> 
>     struct btrfs_ioctl_quota_rescan_args {
>         __u64   flags;
>         __u64   progress;
>         __u64   reserved[6];
>     };
> 
>     If there is a rescan operation running, 'flags' field is set to 1, and
>     'progress' field is set to aproppriate value which represents the progress
>     of the operation.
> 
> BTRFS_IOC_QUOTA_RESCAN - Starting a rescan operation
> 
>     Start ar rescan operation to Trash all quota groups and scan the metadata
>     again with the current config. Before calling this ioctl,
>     BTRFS_IOC_QUOTA_RESCAN_STATUS sould be run to check if there is already a
>     rescan operation runing. After that ioctl call, the received
>     'struct btrfs_ioctl_quota_rescan_args' should be than passed as this ioctls
>     third argument.
> 
> BTRFS_IOC_QUOTA_RESCAN_WAIT - Waiting for a rescan operation to finish
> 
>     Wait until a rescan operation is finished (if there is a rescan operation
>     running). The third ioctls argument is ignored.
> 
> Implementation notes:
> 
>     Almost all of the ioctls in this patch use structure types as third arguments.
>     That is the reason why aproppriate thunk definitions were added in file
>     'syscall_types.h'.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/ioctls.h        | 27 +++++++++++++++++++++++++++
>  linux-user/syscall_defs.h  | 14 ++++++++++++++
>  linux-user/syscall_types.h | 29 +++++++++++++++++++++++++++++
>  3 files changed, 70 insertions(+)
> 
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index 2c553103e6..8665f504bf 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -227,6 +227,33 @@
>       IOCTL(BTRFS_IOC_LOGICAL_INO, IOC_RW,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_logical_ino_args)))
>  #endif
> +#ifdef BTRFS_IOC_QUOTA_CTL
> +     IOCTL(BTRFS_IOC_QUOTA_CTL, IOC_RW,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_quota_ctl_args)))
> +#endif
> +#ifdef BTRFS_IOC_QGROUP_ASSIGN
> +     IOCTL(BTRFS_IOC_QGROUP_ASSIGN, IOC_W,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_qgroup_assign_args)))
> +#endif
> +#ifdef BTRFS_IOC_QGROUP_CREATE
> +     IOCTL(BTRFS_IOC_QGROUP_CREATE, IOC_W,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_qgroup_create_args)))
> +#endif
> +#ifdef BTRFS_IOC_QGROUP_LIMIT
> +     IOCTL(BTRFS_IOC_QGROUP_LIMIT, IOC_R,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_qgroup_limit_args)))
> +#endif
> +#ifdef BTRFS_IOC_QUOTA_RESCAN
> +     IOCTL(BTRFS_IOC_QUOTA_RESCAN, IOC_W,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_quota_rescan_args)))
> +#endif
> +#ifdef BTRFS_IOC_QUOTA_RESCAN_STATUS
> +     IOCTL(BTRFS_IOC_QUOTA_RESCAN_STATUS, IOC_R,
> +           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_quota_rescan_args)))
> +#endif
> +#ifdef BTRFS_IOC_QUOTA_RESCAN_WAIT
> +     IOCTL(BTRFS_IOC_QUOTA_RESCAN_WAIT, 0, TYPE_NULL)
> +#endif
>  #ifdef BTRFS_IOC_GET_DEV_STATS
>       IOCTL(BTRFS_IOC_GET_DEV_STATS, IOC_RW,
>             MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_get_dev_stats)))
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index f4b4fc4a20..3f771ae5d1 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -996,6 +996,20 @@ struct target_rtc_pll_info {
>                                            35, struct btrfs_ioctl_ino_path_args)
>  #define TARGET_BTRFS_IOC_LOGICAL_INO            TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
>                                         36, struct btrfs_ioctl_logical_ino_args)
> +#define TARGET_BTRFS_IOC_QUOTA_CTL              TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> +                                         40, struct btrfs_ioctl_quota_ctl_args)
> +#define TARGET_BTRFS_IOC_QGROUP_ASSIGN          TARGET_IOW(BTRFS_IOCTL_MAGIC, \
> +                                     41, struct btrfs_ioctl_qgroup_assign_args)
> +#define TARGET_BTRFS_IOC_QGROUP_CREATE          TARGET_IOW(BTRFS_IOCTL_MAGIC, \
> +                                     42, struct btrfs_ioctl_qgroup_create_args)
> +#define TARGET_BTRFS_IOC_QGROUP_LIMIT           TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> +                                      43, struct btrfs_ioctl_qgroup_limit_args)
> +#define TARGET_BTRFS_IOC_QUOTA_RESCAN           TARGET_IOW(BTRFS_IOCTL_MAGIC, \
> +                                      44, struct btrfs_ioctl_quota_rescan_args)
> +#define TARGET_BTRFS_IOC_QUOTA_RESCAN_STATUS    TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> +                                      45, struct btrfs_ioctl_quota_rescan_args)

With the 'U' variant:

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

Thanks,
Laurent