BlockDriver->bdrv_getlength is categorized as IO callback, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since the callback traverses the block nodes graph, which however is only possible in a coroutine. Therefore turn it into a co_wrapper to move the actual function into a coroutine where the lock can be taken. Because now this function creates a new coroutine and polls, we need to take the AioContext lock where it is missing, for the only reason that internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the AioContext lock. This is especially messy when a co_wrapper creates a coroutine and polls in bdrv_open_driver, because this function has so many callers in so many context that it can easily lead to deadlocks. Therefore the new rule for bdrv_open_driver is that the caller must always hold the AioContext lock of the given bs (except if it is a coroutine), because the function calls bdrv_refresh_total_sectors() which is now a co_wrapper. Once the rwlock is ultimated and placed in every place it needs to be, we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext lock. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-7-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> |
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.. | ||
avocado | ||
bench | ||
data | ||
decode | ||
docker | ||
fp | ||
guest-debug | ||
image-fuzzer | ||
include | ||
keys | ||
lcitool | ||
migration | ||
multiboot | ||
perf/block/qcow2 | ||
plugin | ||
qapi-schema | ||
qemu-iotests | ||
qtest | ||
rocker | ||
tcg | ||
tsan | ||
uefi-test-tools | ||
unit | ||
vm | ||
vmstate-static-checker-data | ||
Makefile.include | ||
check-block.sh | ||
dbus-vmstate-daemon.sh | ||
meson.build | ||
requirements.txt | ||
test-qht-par.c | ||
vhost-user-bridge.c |