Re: [Qemu-devel] [PATCH v5 3/5] block: Add driver methods to probe blocksizes and geometry

[Thomas Huth]

On Thu, 18 Dec 2014 12:18:02 +0100
Ekaterina Tumanova <address@hidden> wrote:

> Introduce driver methods of defining disk blocksizes (physical and
> logical) and hard drive geometry.
> Methods are only implemented for "host_device". For "raw" devices
> driver calls child's method.
> 
> For now geometry detection will only work for DASD devices. To check
> that a local check_for_dasd function was introduced. It calls BIODASDINFO2
> ioctl and returns its rc.
> 
> Blocksizes detection function will probe sizes for DASD devices and
> set default for other devices.
> 
> Signed-off-by: Ekaterina Tumanova <address@hidden>
> Reviewed-by: Markus Armbruster <address@hidden>
> ---
>  block/raw-posix.c | 97 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  block/raw_bsd.c   | 14 ++++++++
>  2 files changed, 111 insertions(+)
> 
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 38172ca..1783acf 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -56,6 +56,7 @@
>  #include <linux/cdrom.h>
>  #include <linux/fd.h>
>  #include <linux/fs.h>
> +#include <linux/hdreg.h>
>  #ifndef FS_NOCOW_FL
>  #define FS_NOCOW_FL                     0x00800000 /* Do not cow file */
>  #endif
> @@ -90,6 +91,10 @@
>  #include <xfs/xfs.h>
>  #endif
> 
> +#ifdef __s390__
> +#include <asm/dasd.h>
> +#endif
> +
>  //#define DEBUG_FLOPPY
> 
>  //#define DEBUG_BLOCK
> @@ -238,6 +243,23 @@ static int probe_logical_blocksize(int fd, unsigned int 
> *sector_size)
>  #undef SECTOR_SIZE
>  }
> 
> +/**
> + * Get physical block size of @fd.
> + * On success, store it in @blk_size and return 0.
> + * On failure, return -errno.
> + */
> +static int probe_physical_blocksize(int fd, unsigned int *blk_size)
> +{
> +#ifdef BLKPBSZGET
> +    if (ioctl(fd, BLKPBSZGET, blk_size) < 0) {
> +        return -errno;
> +    }
> +    return 0;
> +#else
> +    return -ENOTSUP;
> +#endif
> +}
> +
>  static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
>  {
>      BDRVRawState *s = bs->opaque;
> @@ -660,6 +682,79 @@ static void raw_refresh_limits(BlockDriverState *bs, 
> Error **errp)
>      bs->bl.opt_mem_alignment = s->buf_align;
>  }
> 
> +static int check_for_dasd(int fd)
> +{
> +#ifdef BIODASDINFO2
> +    struct dasd_information2_t info = {0};
> +
> +    return ioctl(fd, BIODASDINFO2, &info);
> +#else
> +    return -1;
> +#endif
> +}
> +
> +/**
> + * Try to get @bs's logical and physical block size.
> + * On success, store them in @bsz and return zero.
> + * On failure, return negative errno.
> + */
> +static int hdev_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
> +{
> +    BDRVRawState *s = bs->opaque;
> +    int ret;
> +
> +    /* If DASD, get blocksizes */
> +    if (check_for_dasd(s->fd) < 0) {
> +        return -ENOTSUP;
> +    }
> +    ret = probe_logical_blocksize(s->fd, &bsz->log);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +    return probe_physical_blocksize(s->fd, &bsz->phys);
> +}
> +
> +/**
> + * Try to get @bs's geometry (cyls, heads, sectos)
> + * On success, store them in @geo and return 0.
> + * On failure return -errno.
> + * (as for 12/2014 only DASDs are supported)
> + */
> +static int hdev_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
> +{
> +    BDRVRawState *s = bs->opaque;
> +    struct hd_geometry ioctl_geo = {0};
> +    uint32_t blksize;
> +
> +    /* If DASD, get it's geometry */

s/it's/its/

> +    if (check_for_dasd(s->fd) < 0) {
> +        return -ENOTSUP;
> +    }
> +    if (ioctl(s->fd, HDIO_GETGEO, &ioctl_geo) < 0) {
> +        return -errno;
> +    }
> +    /* HDIO_GETGEO may return success even though geo contains zeros
> +       (e.g. certain multipath setups) */
> +    if (!ioctl_geo.heads || !ioctl_geo.sectors || !ioctl_geo.cylinders) {
> +        return -ENOTSUP;
> +    }
> +    /* Do not return a geometry for partition */
> +    if (ioctl_geo.start != 0) {
> +        return -ENOTSUP;
> +    }
> +    geo->heads = ioctl_geo.heads;
> +    geo->sectors = ioctl_geo.sectors;
> +    if (!probe_physical_blocksize(s->fd, &blksize)) {
> +        /* overwrite cyls: HDIO_GETGEO result is incorrect for big drives */
> +        geo->cylinders = bs->total_sectors / (blksize / BDRV_SECTOR_SIZE)
> +                                           / (geo->heads * geo->sectors);
> +        return 0;
> +    }
> +    geo->cylinders = ioctl_geo.cylinders;
> +
> +    return 0;
> +}
> +
>  static ssize_t handle_aiocb_ioctl(RawPosixAIOData *aiocb)
>  {
>      int ret;
> @@ -2125,6 +2220,8 @@ static BlockDriver bdrv_host_device = {
>      .bdrv_get_info = raw_get_info,
>      .bdrv_get_allocated_file_size
>                          = raw_get_allocated_file_size,
> +    .bdrv_probe_blocksizes = hdev_probe_blocksizes,
> +    .bdrv_probe_geometry = hdev_probe_geometry,
> 
>      .bdrv_detach_aio_context = raw_detach_aio_context,
>      .bdrv_attach_aio_context = raw_attach_aio_context,
> diff --git a/block/raw_bsd.c b/block/raw_bsd.c
> index 05b02c7..f3d532b 100644
> --- a/block/raw_bsd.c
> +++ b/block/raw_bsd.c
> @@ -235,6 +235,18 @@ static int raw_probe(const uint8_t *buf, int buf_size, 
> const char *filename)
>      return 1;
>  }
> 
> +static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
> +{
> +    bdrv_probe_blocksizes(bs->file, bsz);
> +
> +    return 0;
> +}
> +
> +static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
> +{
> +    return bdrv_probe_geometry(bs->file, geo);
> +}
> +
>  BlockDriver bdrv_raw = {
>      .format_name          = "raw",
>      .bdrv_probe           = &raw_probe,
> @@ -252,6 +264,8 @@ BlockDriver bdrv_raw = {
>      .has_variable_length  = true,
>      .bdrv_get_info        = &raw_get_info,
>      .bdrv_refresh_limits  = &raw_refresh_limits,
> +    .bdrv_probe_blocksizes = &raw_probe_blocksizes,
> +    .bdrv_probe_geometry  = &raw_probe_geometry,
>      .bdrv_is_inserted     = &raw_is_inserted,
>      .bdrv_media_changed   = &raw_media_changed,
>      .bdrv_eject           = &raw_eject,

Looks good to me now (apart from the very minor typo).

Reviewed-by: Thomas Huth <address@hidden>