Blame SOURCES/kvm-virtio-blk-Bypass-error-action-and-I-O-accounting-on.patch

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From 8406a85d6b78d2f3478a204b5eab0cd714fe9aa4 Mon Sep 17 00:00:00 2001
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From: Markus Armbruster <armbru@redhat.com>
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Date: Fri, 31 Oct 2014 16:29:53 +0100
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Subject: [PATCH 16/19] virtio-blk: Bypass error action and I/O accounting on
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 invalid r/w
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Message-id: <1414772996-17272-3-git-send-email-armbru@redhat.com>
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Patchwork-id: 62014
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O-Subject: [PATCH RHEL-7.1 qemu-kvm 2/5] virtio-blk: Bypass error action and I/O accounting on invalid r/w
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Bugzilla: 1085232
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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When a device model's I/O operation fails, we execute the error
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action.  This lets layers above QEMU implement thin provisioning, or
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attempt to correct errors before they reach the guest.  But when the
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I/O operation fails because it's invalid, reporting the error to the
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guest is the only sensible action.
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If the guest's read or write asks for an invalid sector range, fail
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the request right away, without considering the error action.  No
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change with error action BDRV_ACTION_REPORT.
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Furthermore, bypass I/O accounting, because we want to track only I/O
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that actually reaches the block layer.
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The next commit will extend "invalid sector range" to cover attempts
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to read/write beyond the end of the medium.
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Signed-off-by: Markus Armbruster <armbru@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 42e38c1fd0199155d32f3464aedce282d3d7f6a1)
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Straightforward semantic conflict: requests still have to be freed
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with g_free() because we don't have commit 671ec3f.
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Signed-off-by: Markus Armbruster <armbru@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/block/virtio-blk.c | 14 ++++++++------
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 1 file changed, 8 insertions(+), 6 deletions(-)
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diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
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index 0f1d3ec..ffb311c 100644
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--- a/hw/block/virtio-blk.c
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+++ b/hw/block/virtio-blk.c
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@@ -300,15 +300,16 @@ static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
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     sector = ldq_p(&req->out->sector);
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-    bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE);
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-
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     trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
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     if (!virtio_blk_sect_range_ok(req->dev, sector, req->qiov.size)) {
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-        virtio_blk_rw_complete(req, -EIO);
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+        virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
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+        g_free(req);
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         return;
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     }
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+    bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE);
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+
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     if (mrb->num_writes == 32) {
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         virtio_submit_multiwrite(req->dev->bs, mrb);
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     }
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@@ -330,14 +331,15 @@ static void virtio_blk_handle_read(VirtIOBlockReq *req)
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     sector = ldq_p(&req->out->sector);
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-    bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ);
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-
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     trace_virtio_blk_handle_read(req, sector, req->qiov.size / 512);
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     if (!virtio_blk_sect_range_ok(req->dev, sector, req->qiov.size)) {
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-        virtio_blk_rw_complete(req, -EIO);
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+        virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
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+        g_free(req);
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         return;
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     }
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+
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+    bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ);
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     bdrv_aio_readv(req->dev->bs, sector, &req->qiov,
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                    req->qiov.size / BDRV_SECTOR_SIZE,
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                    virtio_blk_rw_complete, req);
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-- 
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1.8.3.1
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