Kevin Wolf 411132c979 export/vhost-user-blk: Fix consecutive drains ... The vhost-user-blk export implement AioContext switches in its drain implementation. This means that on drain_begin, it detaches the server from its AioContext and on drain_end, attaches it again and schedules the server->co_trip coroutine in the updated AioContext. However, nothing guarantees that server->co_trip is even safe to be scheduled. Not only is it unclear that the coroutine is actually in a state where it can be reentered externally without causing problems, but with two consecutive drains, it is possible that the scheduled coroutine didn't have a chance yet to run and trying to schedule an already scheduled coroutine a second time crashes with an assertion failure. Following the model of NBD, this commit makes the vhost-user-blk export shut down server->co_trip during drain so that resuming the export means creating and scheduling a new coroutine, which is always safe. There is one exception: If the drain call didn't poll (for example, this happens in the context of bdrv_graph_wrlock()), then the coroutine didn't have a chance to shut down. However, in this case the AioContext can't have changed; changing the AioContext always involves a polling drain. So in this case we can simply assert that the AioContext is unchanged and just leave the coroutine running or wake it up if it has yielded to wait for the AioContext to be attached again. Fixes: e1054cd4aa Fixes: https://issues.redhat.com/browse/RHEL-1708 Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231127115755.22846-1-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>		2023-11-28 14:56:32 +01:00
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aio-posix.c
aio-posix.h
aio-wait.c
aio-win32.c
aiocb.c
async.c
atomic64.c
base64.c
bitmap.c
bitops.c
block-helpers.c
block-helpers.h
buffer.c
bufferiszero.c
cacheflush.c
compatfd.c
coroutine-sigaltstack.c
coroutine-ucontext.c
coroutine-windows.c
cpuinfo-aarch64.c
cpuinfo-i386.c
cpuinfo-loongarch.c
cpuinfo-ppc.c
crc32c.c
crc-ccitt.c
cutils.c
dbus.c
defer-call.c
drm.c
envlist.c
error-report.c
error.c
event_notifier-posix.c
event_notifier-win32.c
fdmon-epoll.c
fdmon-io_uring.c
fdmon-poll.c
fifo8.c
filemonitor-inotify.c
filemonitor-stub.c
getauxval.c
guest-random.c
hbitmap.c
hexdump.c
host-utils.c
id.c
int128.c
interval-tree.c
iov.c
iova-tree.c
keyval.c
lockcnt.c
log.c
main-loop.c
memalign.c
memfd.c
meson.build
mmap-alloc.c
module.c
notify.c
nvdimm-utils.c
osdep.c
oslib-posix.c
oslib-win32.c
path.c
qdist.c
qemu-co-shared-resource.c
qemu-co-timeout.c
qemu-config.c
qemu-coroutine-io.c
qemu-coroutine-lock.c
qemu-coroutine-sleep.c
qemu-coroutine.c
qemu-option.c
qemu-print.c
qemu-progress.c
qemu-sockets.c
qemu-thread-common.h
qemu-thread-posix.c
qemu-thread-win32.c
qemu-timer-common.c
qemu-timer.c
qht.c
qsp.c
qtree.c
range.c
rcu.c
readline.c
reserved-region.c
selfmap.c
stats64.c
sys_membarrier.c
systemd.c
thread-context.c
thread-pool.c
throttle.c
timed-average.c
trace-events
trace.h
transactions.c
unicode.c
uri.c
userfaultfd.c
uuid.c
vfio-helpers.c
vhost-user-server.c	export/vhost-user-blk: Fix consecutive drains	2023-11-28 14:56:32 +01:00
yank.c