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vhost-blk: process VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP correctly

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Flag VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP is only used for WRITE
ZEROES command, vhost-blk target may tell VM via 'write_zeroes_may_unmap'
configuration that the backend can support this flag, however, Linux
generic block driver doesn't have such logic, it will enable this
flag by default(without REQ_NOUNMAP) with WRITE ZEROES command,
so the backend may choose to ignore this flag, because WRITE ZEROES
with this flag isn't mandatory.

Fix issue #1714.

Change-Id: Ic9388f39269720a23c00d41cba585d2a5abc3cfb
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/5565
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: <dongx.yi@intel.com>
This commit is contained in:
Changpeng Liu 2020-12-14 00:59:25 -05:00 committed by Tomasz Zawadzki
parent dffb272c1a
commit e18788d30e
1 changed files with 12 additions and 4 deletions
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16
lib/vhost/vhost_blk.c
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@ -464,6 +464,12 @@ process_blk_request(struct spdk_vhost_blk_task *task,
return -1;
}
if (desc->flags & VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP) {
SPDK_ERRLOG("UNMAP flag is only used for WRITE ZEROES command\n");
invalid_blk_request(task, VIRTIO_BLK_S_UNSUPP);
return -1;
}
rc = spdk_bdev_unmap(bvdev->bdev_desc, bvsession->io_channel,
desc->sector * 512, desc->num_sectors * 512,
blk_request_complete_cb, task);
@ -485,11 +491,13 @@ process_blk_request(struct spdk_vhost_blk_task *task,
return -1;
}
/* Zeroed and Unmap the range, SPDK doen't support it. */
/* Unmap this range, SPDK doesn't support it, kernel will enable this flag by default
* without checking unmap feature is negociated or not, the flag isn't mandatory, so
* just print a warning.
*/
if (desc->flags & VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP) {
SPDK_NOTICELOG("Can't support Write Zeroes with Unmap flag\n");
invalid_blk_request(task, VIRTIO_BLK_S_UNSUPP);
return -1;
SPDK_WARNLOG("Ignore the unmap flag for WRITE ZEROES from %"PRIx64", len %"PRIx64"\n",
(uint64_t)desc->sector * 512, (uint64_t)desc->num_sectors * 512);
}
rc = spdk_bdev_write_zeroes(bvdev->bdev_desc, bvsession->io_channel,