linux-user: Add support for btrfs ioctls used to scrub a filesystem

This patch implements functionality for following ioctls:

BTRFS_IOC_SCRUB - Starting a btrfs filesystem scrub

    Start a btrfs filesystem scrub. The third ioctls argument
    is a pointer to a following type:

    struct btrfs_ioctl_scrub_args {
	__u64 devid;				/* in */
	__u64 start;				/* in */
	__u64 end;				/* in */
	__u64 flags;				/* in */
	struct btrfs_scrub_progress progress;	/* out */
	/* pad to 1k */
	__u64 unused[(1024-32-sizeof(struct btrfs_scrub_progress))/8];
    };

    Before calling this ioctl, field 'devid' should be filled
    with value that represents the device id of the btrfs filesystem
    for which the scrub is to be started.

BTRFS_IOC_SCRUB_CANCEL - Canceling scrub of a btrfs filesystem

    Cancel a btrfs filesystem scrub if it is running. The third
    ioctls argument is ignored.

BTRFS_IOC_SCRUB_PROGRESS - Getting status of a running scrub

    Read the status of a running btrfs filesystem scrub. The third
    ioctls argument is a pointer to the above mentioned
    'struct btrfs_ioctl_scrub_args'. Similarly as with 'BTRFS_IOC_SCRUB',
    the 'devid' field should be filled with value that represents the
    id of the btrfs device for which the scrub has started. The status
    of a running scrub is returned in the field 'progress' which is
    of type 'struct btrfs_scrub_progress' and its definition can be
    found at:
    https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/btrfs.h#L150

Implementation nots:

    Ioctls in this patch use type 'struct btrfs_ioctl_scrub_args' as their
    third argument. That is the reason why an aproppriate thunk type
    definition is added in file 'syscall_types.h'.

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Tested-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200823195014.116226-9-Filip.Bozuta@syrmia.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

3 files changed, 43 insertions, 0 deletions

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index 42759c0778..585874f090 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -215,6 +215,17 @@
 #ifdef BTRFS_IOC_SUBVOL_SETFLAGS
      IOCTL(BTRFS_IOC_SUBVOL_SETFLAGS, IOC_W, MK_PTR(TYPE_ULONGLONG))
 #endif
+#ifdef BTRFS_IOC_SCRUB
+     IOCTL(BTRFS_IOC_SCRUB, IOC_RW,
+           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_scrub_args)))
+#endif
+#ifdef BTRFS_IOC_SCRUB_CANCEL
+     IOCTL(BTRFS_IOC_SCRUB_CANCEL, 0, TYPE_NULL)
+#endif
+#ifdef BTRFS_IOC_SCRUB_PROGRESS
+     IOCTL(BTRFS_IOC_SCRUB_PROGRESS, IOC_RW,
+           MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_scrub_args)))
+#endif
 #ifdef BTRFS_IOC_DEV_INFO
      IOCTL(BTRFS_IOC_DEV_INFO, IOC_RW,
            MK_PTR(MK_STRUCT(STRUCT_btrfs_ioctl_dev_info_args)))
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index b557b07eec..33a414c50f 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -1020,6 +1020,9 @@ struct target_rtc_pll_info {
                                                            abi_ullong)
 #define TARGET_BTRFS_IOC_SUBVOL_SETFLAGS        TARGET_IOW(BTRFS_IOCTL_MAGIC, 26,\
                                                            abi_ullong)
+#define TARGET_BTRFS_IOC_SCRUB                  TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 27)
+#define TARGET_BTRFS_IOC_SCRUB_CANCEL           TARGET_IO(BTRFS_IOCTL_MAGIC, 28)
+#define TARGET_BTRFS_IOC_SCRUB_PROGRESS         TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 29)
 #define TARGET_BTRFS_IOC_DEV_INFO               TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 30)
 #define TARGET_BTRFS_IOC_INO_PATHS              TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 35)
 #define TARGET_BTRFS_IOC_LOGICAL_INO            TARGET_IOWRU(BTRFS_IOCTL_MAGIC, 36)
diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
index 51d9931b95..ba2c1518eb 100644
--- a/linux-user/syscall_types.h
+++ b/linux-user/syscall_types.h
@@ -425,6 +425,35 @@ STRUCT(btrfs_ioctl_ino_lookup_user_args,
        MK_ARRAY(TYPE_CHAR, BTRFS_INO_LOOKUP_USER_PATH_MAX)) /* path */
 #endif
 
+#if defined(BTRFS_IOC_SCRUB) || defined(BTRFS_IOC_SCRUB_PROGRESS)
+STRUCT(btrfs_scrub_progress,
+       TYPE_ULONGLONG, /* data_extents_scrubbed */
+       TYPE_ULONGLONG, /* tree_extents_scrubbed */
+       TYPE_ULONGLONG, /* data_bytes_scrubbed */
+       TYPE_ULONGLONG, /* tree_bytes_scrubbed */
+       TYPE_ULONGLONG, /* read_errors */
+       TYPE_ULONGLONG, /* csum_errors */
+       TYPE_ULONGLONG, /* verify_errors */
+       TYPE_ULONGLONG, /* no_csum */
+       TYPE_ULONGLONG, /* csum_discards */
+       TYPE_ULONGLONG, /* super_errors */
+       TYPE_ULONGLONG, /* malloc_errors */
+       TYPE_ULONGLONG, /* uncorrectable_errors */
+       TYPE_ULONGLONG, /* corrected_er */
+       TYPE_ULONGLONG, /* last_physical */
+       TYPE_ULONGLONG) /* unverified_errors */
+
+STRUCT(btrfs_ioctl_scrub_args,
+       TYPE_ULONGLONG, /* devid */
+       TYPE_ULONGLONG, /* start */
+       TYPE_ULONGLONG, /* end */
+       TYPE_ULONGLONG, /* flags */
+       MK_STRUCT(STRUCT_btrfs_scrub_progress), /* progress */
+       MK_ARRAY(TYPE_ULONGLONG,
+                (1024 - 32 -
+                 sizeof(struct btrfs_scrub_progress)) / 8)) /* unused */
+#endif
+
 #ifdef BTRFS_IOC_DEV_INFO
 STRUCT(btrfs_ioctl_dev_info_args,
        TYPE_ULONGLONG, /* devid */