diff options
| author | Andrea Arcangeli <aarcange@redhat.com> | 2009-06-04 15:41:22 +0200 |
|---|---|---|
| committer | Eduardo Habkost <ehabkost@redhat.com> | 2009-06-08 10:34:06 -0300 |
| commit | bbb21f907d1abbc75aa36a8adcbc5e1cfd800910 (patch) | |
| tree | 4e023421c1cef460ac5ef7958647af84d4e3fd4e | |
| parent | 7a6cf633acf9a685cacbc1a38cf07f439c678780 (diff) | |
fix qemu_aio_flush
This is for all kvm-userland-rhel5 and shall fix bug #489205.
----
From: Andrea Arcangeli <aarcange@redhat.com>
qemu_aio_wait by invoking the bh or one of the aio completion
callbacks, could end up submitting new pending aio, breaking the
invariant that qemu_aio_flush returns only when no pending aio is
outstanding (possibly a problem for migration as such).
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Message-ID: <20090604134122.GV25483@random.random>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Dor Laor <dlaor@redhat.com>
Bugzilla: 504237
| -rw-r--r-- | qemu/aio.c | 8 | ||||
| -rw-r--r-- | qemu/qemu-aio.h | 7 |
2 files changed, 10 insertions, 5 deletions
@@ -104,11 +104,15 @@ void qemu_aio_flush(void) do { ret = 0; + /* + * If there are pending emulated aio start them now so flush + * will be able to return 1. + */ + qemu_aio_wait(); + LIST_FOREACH(node, &aio_handlers, node) { ret |= node->io_flush(node->opaque); } - - qemu_aio_wait(); } while (ret > 0); } diff --git a/qemu/qemu-aio.h b/qemu/qemu-aio.h index 79678293..f262344a 100644 --- a/qemu/qemu-aio.h +++ b/qemu/qemu-aio.h @@ -24,9 +24,10 @@ typedef int (AioFlushHandler)(void *opaque); * outstanding AIO operations have been completed or cancelled. */ void qemu_aio_flush(void); -/* Wait for a single AIO completion to occur. This function will until a - * single AIO opeartion has completed. It is intended to be used as a looping - * primative when simulating synchronous IO based on asynchronous IO. */ +/* Wait for a single AIO completion to occur. This function will wait + * until a single AIO event has completed and it will ensure something + * has moved before returning. This can issue new pending aio as + * result of executing I/O completion or bh callbacks. */ void qemu_aio_wait(void); /* Register a file descriptor and associated callbacks. Behaves very similarly |