update backup patches

[pve-qemu-kvm.git] / debian / patches / fix-aio-poll.patch

aio_poll() must return true if any work is still pending, even if it didn't make progress, so that qemu_aio_wait() doesn't return too early.
The possibility of returning early occasionally lead to a failed assertion in bdrv_drain_all(), when some in-flight request was missed and the function didn't really drain all requests.

In order to make that change, the return value as specified in the function comment must change for blocking = false; fortunately, the return value of blocking = false callers is only used in test cases, so this change shouldn't cause any trouble.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 aio-posix.c         |    3 ++-
 include/block/aio.h |    6 ++----
 tests/test-aio.c    |    4 ++--
 3 files changed, 6 insertions(+), 7 deletions(-)

Index: new/aio-posix.c
===================================================================
--- new.orig/aio-posix.c	2013-01-22 07:10:17.000000000 +0100
+++ new/aio-posix.c	2013-01-22 07:10:43.000000000 +0100
@@ -264,5 +264,6 @@
         }
     }
 
-    return progress;
+    assert(progress || busy);
+    return true;
 }
Index: new/qemu-aio.h
===================================================================
--- new.orig/qemu-aio.h	2013-01-22 07:10:17.000000000 +0100
+++ new/qemu-aio.h	2013-01-22 07:10:43.000000000 +0100
@@ -177,16 +177,14 @@
  * aio as a result of executing I/O completion or bh callbacks.
  *
  * If there is no pending AIO operation or completion (bottom half),
- * return false.  If there are pending bottom halves, return true.
+ * return false.  If there are pending AIO operations of bottom halves,
+ * return true.
  *
  * If there are no pending bottom halves, but there are pending AIO
  * operations, it may not be possible to make any progress without
  * blocking.  If @blocking is true, this function will wait until one
  * or more AIO events have completed, to ensure something has moved
  * before returning.
- *
- * If @blocking is false, this function will also return false if the
- * function cannot make any progress without blocking.
  */
 bool aio_poll(AioContext *ctx, bool blocking);
 
Index: new/tests/test-aio.c
===================================================================
--- new.orig/tests/test-aio.c	2013-01-22 07:10:17.000000000 +0100
+++ new/tests/test-aio.c	2013-01-22 07:10:43.000000000 +0100
@@ -315,13 +315,13 @@
     event_notifier_set(&data.e);
     g_assert(aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 1);
-    g_assert(!aio_poll(ctx, false));
+    g_assert(aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 1);
 
     event_notifier_set(&data.e);
     g_assert(aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 2);
-    g_assert(!aio_poll(ctx, false));
+    g_assert(aio_poll(ctx, false));
     g_assert_cmpint(data.n, ==, 2);
 
     event_notifier_set(&dummy.e);