From 5793eb73d4d6d37293c6ca95ed85414fcccb9662 Mon Sep 17 00:00:00 2001

From: Filip Bozuta <Filip.Bozuta@syrmia.com>

Date: Thu, 3 Sep 2020 01:26:57 +0200

Subject: [PATCH 5/9] linux-user: Add support for btrfs ioctls used to get/set

 features

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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>

Tested-by: Daniel P. Berrangé <berrange@redhat.com>

Message-Id: <20200823195014.116226-5-Filip.Bozuta@syrmia.com>

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

---

 linux-user/ioctls.h        | 12 ++++++++++++

 linux-user/syscall_defs.h  |  3 +++

 linux-user/syscall_types.h |  5 +++++

 3 files changed, 20 insertions(+)

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h

index 55a6cbeca5..50fae1e33b 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 4c7bfa0391..44811fdcbb 100644

--- a/linux-user/syscall_defs.h

+++ b/linux-user/syscall_defs.h

@@ -981,6 +981,9 @@ struct target_rtc_pll_info {

                                                            abi_ullong)

 #define TARGET_BTRFS_IOC_DEV_INFO               TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 30)

 #define TARGET_BTRFS_IOC_GET_DEV_STATS          TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 52)

+#define TARGET_BTRFS_IOC_GET_FEATURES           TARGET_IORU(BTRFS_IOCTL_MAGIC, 57)

+#define TARGET_BTRFS_IOC_SET_FEATURES           TARGET_IOWU(BTRFS_IOCTL_MAGIC, 57)

+#define TARGET_BTRFS_IOC_GET_SUPPORTED_FEATURES TARGET_IORU(BTRFS_IOCTL_MAGIC, 57)

 #define TARGET_BTRFS_IOC_GET_SUBVOL_INFO        TARGET_IORU(BTRFS_IOCTL_MAGIC, 60)

 /* usb ioctls */

diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h

index ea6898979b..925054cfd4 100644

--- a/linux-user/syscall_types.h

+++ b/linux-user/syscall_types.h

@@ -409,6 +409,11 @@ STRUCT(btrfs_ioctl_get_dev_stats,

                 128 - 2 - BTRFS_DEV_STAT_VALUES_MAX)) /* unused */

 #endif

+STRUCT(btrfs_ioctl_feature_flags,

+       TYPE_ULONGLONG, /* compat_flags */

+       TYPE_ULONGLONG, /* compat_ro_flags */

+       TYPE_ULONGLONG) /* incompat_flags */

+

 STRUCT(rtc_time,

        TYPE_INT, /* tm_sec */

        TYPE_INT, /* tm_min */

-- 

2.26.2