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From 0e7b328d0802c970f632f50d6daab0ea6d226b29 Mon Sep 17 00:00:00 2001
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From: Eric Blake <eblake@redhat.com>
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Date: Wed, 20 Aug 2014 16:40:10 +0200
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Subject: [PATCH 07/11] mirror: Go through ready -> complete process for 0 len image
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Message-id: <1408552814-23031-4-git-send-email-eblake@redhat.com>
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Patchwork-id: 60645
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O-Subject: [qemu-kvm-rhev 7.0.z PATCH 3/7] mirror: Go through ready -> complete process for 0 len image
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Bugzilla: 1130603
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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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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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From: Fam Zheng <famz@redhat.com>
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When mirroring or active committing a zero length image, BLOCK_JOB_READY
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is not reported now, instead the job completes because we short circuit
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the mirror job loop.
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This is inconsistent with non-zero length images, and only confuses
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management software.
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Let's do the same thing when seeing a 0-length image: report ready
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immediately; wait for block-job-cancel or block-job-complete; clear the
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cancel flag as existing non-zero image synced case (cancelled after
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ready); then jump to the exit.
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Reported-by: Eric Blake <eblake@redhat.com>
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Reviewed-by: Eric Blake <eblake@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 9e48b025400b2d284e17860862b0a4aa02c6032d)
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Conflicts:
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	block/mirror.c - no backport of qapi events
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Signed-off-by: Eric Blake <eblake@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/mirror.c |   11 ++++++++++-
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 1 files changed, 10 insertions(+), 1 deletions(-)
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diff --git a/block/mirror.c b/block/mirror.c
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index 9b3e229..cdc0268 100644
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--- a/block/mirror.c
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+++ b/block/mirror.c
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@@ -306,9 +306,18 @@ static void coroutine_fn mirror_run(void *opaque)
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     }
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     s->common.len = bdrv_getlength(bs);
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-    if (s->common.len <= 0) {
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+    if (s->common.len < 0) {
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         ret = s->common.len;
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         goto immediate_exit;
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+    } else if (s->common.len == 0) {
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+        /* Report BLOCK_JOB_READY and wait for complete. */
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+        block_job_ready(&s->common);
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+        s->synced = true;
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+        while (!block_job_is_cancelled(&s->common) && !s->should_complete) {
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+            block_job_yield(&s->common);
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+        }
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+        s->common.cancelled = false;
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+        goto immediate_exit;
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     }
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     length = (bdrv_getlength(bs) + s->granularity - 1) / s->granularity;
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-- 
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1.7.1
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