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Re: [Qemu-devel] [PATCH v3 3/5] block: Add driver methods to probe block
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v3 3/5] block: Add driver methods to probe blocksizes and geometry |
Date: |
Mon, 15 Dec 2014 14:29:16 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Ekaterina Tumanova <address@hidden> writes:
> This patch introduces driver methods of defining disk blocksizes
> (physical and logical) and hard drive geometry.
> The method is only implemented for "host_device". For "raw" devices
> driver calls child's method.
>
> For the time being geometry detection will only work for DASD devices.
> In order to check that a local check_for_dasd function was introduced,
> which calls BIODASDINFO2 ioctl and returns its rc.
>
> Blocksizes detection fuction will probe sizes for DASD devices and
> set default for other devices.
>
> Signed-off-by: Ekaterina Tumanova <address@hidden>
> ---
> block/raw-posix.c | 91
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> block/raw_bsd.c | 14 +++++++++
> 2 files changed, 105 insertions(+)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 633d5bc..33f9983 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
> @@ -242,6 +247,20 @@ static int probe_logical_blocksize(int fd, unsigned int
> *sector_size)
> return 0;
> }
>
> +/*
> + * Set physical block size via ioctl. On success return 0. Otherwise -errno.
> + */
Set?
Ah, now I get your logic, you mean "set *blk_size"!
Suggest to say it like this:
/**
* 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;
> + }
> +#endif
> +
> + return 0;
If !defined(BLKPBSZGET), you return 0 without setting *blk_size. I
think you need to fail then. -ENOTSUP should do.
> +}
> +
> static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
> {
> BDRVRawState *s = bs->opaque;
> @@ -662,6 +681,76 @@ 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);
> +#endif
> + return -1;
> +}
> +
> +/*
> + * Try to get the device blocksize. On success 0. On failure return -errno.
> + * Currently only implemented for DASD drives.
> + */
Compare to the function contract I wrote for the callback in my review
of PATCH 1. If you like that one better, feel free to reuse it here.
> +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 -1;
This is not a negative error code! -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 the device geometry. On success 0. On failure return -errno.
> + * Currently only implemented for DASD drives.
> + */
Compare to the function contract I wrote for the callback in my review
of PATCH 1. If you like that one better, feel free to reuse it here.
> +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 */
> + if (check_for_dasd(s->fd) < 0) {
> + return -1;
This is not a negative error code! -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 -1;
Need an error code.
> + }
> + /* Do not return a geometry for partition */
> + if (ioctl_geo.start != 0) {
> + return -1;
Need an error code.
> + }
> + geo->heads = ioctl_geo.heads;
> + geo->sectors = ioctl_geo.sectors;
> + if (bs->total_sectors) {
> + if (!probe_physical_blocksize(s->fd, &blksize)) {
> + geo->cylinders = bs->total_sectors / (blksize / BDRV_SECTOR_SIZE)
> + / (geo->heads * geo->sectors);
> + return 0;
> + }
> + }
How could !bs->total_sectors happen?
> + geo->cylinders = ioctl_geo.cylinders;
> +
> + return 0;
> +}
> +
> static ssize_t handle_aiocb_ioctl(RawPosixAIOData *aiocb)
> {
> int ret;
> @@ -2127,6 +2216,8 @@ 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 401b967..cfd5249 100644
> --- a/block/raw_bsd.c
> +++ b/block/raw_bsd.c
> @@ -173,6 +173,18 @@ 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;
> +}
Correct, just a bit awkward due to the difference between
bdrv_probe_blocksizes() and ->bdrv_probe_blocksizes(). I guess I'd make
them the same, but it's your patch.
> +
> +static int raw_probe_geometry(BlockDriverState *bs, hdGeometry *geo)
> +{
> + return bdrv_probe_geometry(bs->file, geo);
> +}
> +
> static BlockDriver bdrv_raw = {
> .format_name = "raw",
> .bdrv_probe = &raw_probe,
> @@ -190,6 +202,8 @@ static 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,
[Qemu-devel] [PATCH v3 2/5] raw-posix: Factor block size detection out of raw_probe_alignment(), Ekaterina Tumanova, 2014/12/05
Re: [Qemu-devel] [PATCH v3 0/5] Geometry and blocksize detection for backing devices., Ekaterina Tumanova, 2014/12/12