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H A Dqcow2.cdiff aa269ff888d70158fe0c26ed17814046bdc19bd5 Thu May 25 07:47:07 CDT 2023 Kevin Wolf <kwolf@redhat.com> qcow2: Fix open with 'file' in iothread

qcow2_open() doesn't work correctly when opening the 'file' child moves
bs to an iothread, for several reasons:

- It uses BDRV_POLL_WHILE() to wait for the qcow2_open_entry()
coroutine, which involves dropping the AioContext lock for bs when it
is not in the main context - but we don't hold it, so this crashes.

- It runs the qcow2_open_entry() coroutine in the current thread instead
of the new AioContext of bs.

- qcow2_open_entry() doesn't notify the main loop when it's done.

This patches fixes these issues around delegating work to a coroutine.
Temporarily dropping the main AioContext lock is not necessary because
we know we run in the main thread.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230525124713.401149-7-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
/openbmc/qemu/
H A Dblock.cdiff aa269ff888d70158fe0c26ed17814046bdc19bd5 Thu May 25 07:47:07 CDT 2023 Kevin Wolf <kwolf@redhat.com> qcow2: Fix open with 'file' in iothread

qcow2_open() doesn't work correctly when opening the 'file' child moves
bs to an iothread, for several reasons:

- It uses BDRV_POLL_WHILE() to wait for the qcow2_open_entry()
coroutine, which involves dropping the AioContext lock for bs when it
is not in the main context - but we don't hold it, so this crashes.

- It runs the qcow2_open_entry() coroutine in the current thread instead
of the new AioContext of bs.

- qcow2_open_entry() doesn't notify the main loop when it's done.

This patches fixes these issues around delegating work to a coroutine.
Temporarily dropping the main AioContext lock is not necessary because
we know we run in the main thread.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230525124713.401149-7-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>