Re: [Qemu-devel] [PATCH v4 3/5] block: Add driver methods to probe blocksizes and geometry

[Markus Armbruster <armbru@redhat.com>]

Ekaterina Tumanova <tumanova@linux.vnet.ibm.com> writes:

> 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 <tumanova@linux.vnet.ibm.com>
> ---
>  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..e1e7b29 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 -ENOTSUP;
> +#endif
> +}

This function is confused about its return value: 0/-1 vs. 0/-errno.
Please return -1 instead of -ENOTSUP, or replace it by an is_dasd()
returning bool.

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