Many places in QEMU call qemu_aio_flush() to complete all pending
asynchronous I/O. Most of these places actually want to drain all block
requests but there is block layer API to do so.
This patch introduces the bdrv_drain_all() API to wait for requests
across all BlockDriverStates to complete. As a bonus we perform checks
after qemu_aio_wait() to ensure that requests really have finished.
Signed-off-by: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
---
block-migration.c | 2 +-
block.c | 19 +++++++++++++++++++
block.h | 1 +
blockdev.c | 4 ++--
cpus.c | 2 +-
hw/ide/macio.c | 5 +++--
hw/ide/pci.c | 2 +-
hw/virtio-blk.c | 2 +-
hw/xen_platform.c | 2 +-
qemu-io.c | 4 ++--
savevm.c | 2 +-
xen-mapcache.c | 2 +-
12 files changed, 34 insertions(+), 13 deletions(-)
diff --git a/block-migration.c b/block-migration.c
index 5f104864..423c5a0 100644
--- a/block-migration.c
+++ b/block-migration.c
@@ -387,7 +387,7 @@ static int mig_save_device_dirty(Monitor *mon, QEMUFile *f,
for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
if (bmds_aio_inflight(bmds, sector)) {
- qemu_aio_flush();
+ bdrv_drain_all();
}
if (bdrv_get_dirty(bmds->bs, sector)) {
diff --git a/block.c b/block.c
index 37a96f3..86807d6 100644
--- a/block.c
+++ b/block.c
@@ -846,6 +846,25 @@ void bdrv_close_all(void)
}
}
+/*
+ * Wait for pending requests to complete across all BlockDriverStates
+ *
+ * This function does not flush data to disk, use bdrv_flush_all() for that
+ * after calling this function.
+ */
+void bdrv_drain_all(void)
+{
+ BlockDriverState *bs;
+
+ qemu_aio_flush();
+
+ /* If requests are still pending there is a bug somewhere */
+ QTAILQ_FOREACH(bs, &bdrv_states, list) {
+ assert(QLIST_EMPTY(&bs->tracked_requests));
+ assert(qemu_co_queue_empty(&bs->throttled_reqs));
+ }
+}
+
/* make a BlockDriverState anonymous by removing from bdrv_state list.
Also, NULL terminate the device_name to prevent double remove */
void bdrv_make_anon(BlockDriverState *bs)
diff --git a/block.h b/block.h
index 1d28e85..0dc4905 100644
--- a/block.h
+++ b/block.h
@@ -214,6 +214,7 @@ int bdrv_flush(BlockDriverState *bs);
int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
void bdrv_flush_all(void);
void bdrv_close_all(void);
+void bdrv_drain_all(void);
int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
diff --git a/blockdev.c b/blockdev.c
index af4e239..dbf0251 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -653,7 +653,7 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict,
QObject **ret_data)
goto out;
}
- qemu_aio_flush();
+ bdrv_drain_all();
bdrv_flush(bs);
bdrv_close(bs);
@@ -840,7 +840,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject
**ret_data)
}
/* quiesce block driver; prevent further io */
- qemu_aio_flush();
+ bdrv_drain_all();
bdrv_flush(bs);
bdrv_close(bs);
diff --git a/cpus.c b/cpus.c
index 82530c4..58e173c 100644
--- a/cpus.c
+++ b/cpus.c
@@ -396,7 +396,7 @@ static void do_vm_stop(RunState state)
pause_all_vcpus();
runstate_set(state);
vm_state_notify(0, state);
- qemu_aio_flush();
+ bdrv_drain_all();
bdrv_flush_all();
monitor_protocol_event(QEVENT_STOP, NULL);
}
diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 70b3342..c09d2e0 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -200,8 +200,9 @@ static void pmac_ide_flush(DBDMA_io *io)
{
MACIOIDEState *m = io->opaque;
- if (m->aiocb)
- qemu_aio_flush();
+ if (m->aiocb) {
+ bdrv_drain_all();
+ }
}
/* PowerMac IDE memory IO */
diff --git a/hw/ide/pci.c b/hw/ide/pci.c
index 49b823d..5078c0b 100644
--- a/hw/ide/pci.c
+++ b/hw/ide/pci.c
@@ -309,7 +309,7 @@ void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val)
* aio operation with preadv/pwritev.
*/
if (bm->bus->dma->aiocb) {
- qemu_aio_flush();
+ bdrv_drain_all();
assert(bm->bus->dma->aiocb == NULL);
assert((bm->status & BM_STATUS_DMAING) == 0);
}
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index d6d1f87..4b0d113 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -474,7 +474,7 @@ static void virtio_blk_reset(VirtIODevice *vdev)
* This should cancel pending requests, but can't do nicely until there
* are per-device request lists.
*/
- qemu_aio_flush();
+ bdrv_drain_all();
}
/* coalesce internal state, copy to pci i/o region 0
diff --git a/hw/xen_platform.c b/hw/xen_platform.c
index 5e792f5..e62eaef 100644
--- a/hw/xen_platform.c
+++ b/hw/xen_platform.c
@@ -120,7 +120,7 @@ static void platform_fixed_ioport_writew(void *opaque,
uint32_t addr, uint32_t v
devices, and bit 2 the non-primary-master IDE devices. */
if (val & UNPLUG_ALL_IDE_DISKS) {
DPRINTF("unplug disks\n");
- qemu_aio_flush();
+ bdrv_drain_all();
bdrv_flush_all();
pci_unplug_disks(s->pci_dev.bus);
}
diff --git a/qemu-io.c b/qemu-io.c
index de26422..b35adbb 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -1853,9 +1853,9 @@ int main(int argc, char **argv)
command_loop();
/*
- * Make sure all outstanding requests get flushed the program exits.
+ * Make sure all outstanding requests complete before the program exits.
*/
- qemu_aio_flush();
+ bdrv_drain_all();
if (bs) {
bdrv_delete(bs);
diff --git a/savevm.c b/savevm.c
index f53cd4c..0443554 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2104,7 +2104,7 @@ int load_vmstate(const char *name)
}
/* Flush all IO requests so they don't interfere with the new state. */
- qemu_aio_flush();
+ bdrv_drain_all();
bs = NULL;
while ((bs = bdrv_next(bs))) {
diff --git a/xen-mapcache.c b/xen-mapcache.c
index 7bcb86e..9fecc64 100644
--- a/xen-mapcache.c
+++ b/xen-mapcache.c
@@ -351,7 +351,7 @@ void xen_invalidate_map_cache(void)
MapCacheRev *reventry;
/* Flush pending AIO before destroying the mapcache */
- qemu_aio_flush();
+ bdrv_drain_all();
QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
DPRINTF("There should be no locked mappings at this time, "
--
1.7.7.3
