mirror of https://github.com/proxmox/mirror_qemu
Revert "qed: Implement .bdrv_drain"
This reverts commitmasterdf9a681dc9
. Note that commitdf9a681dc9
included some unrelated hunks, possibly due to a merge failure or an overlooked squash. This only reverts the qed .bdrv_drain() implementation. The qed .bdrv_drain() implementation is unsafe and can lead to a double request completion. Paolo Bonzini reports: "The problem is that bdrv_qed_drain calls qed_plug_allocating_write_reqs unconditionally, but this is not correct if an allocating write is queued. In this case, qed_unplug_allocating_write_reqs will restart the allocating write and possibly cause it to complete. The aiocb however is still in use for the L2/L1 table writes, and will then be completed again as soon as the table writes are stable." For QEMU 2.6 we can simply revert this commit. A full solution for the qed need check timer may be added if the bdrv_drain() implementation is extended. Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1457431876-8475-1-git-send-email-stefanha@redhat.com
parent
147dfab747
commit
1f3ddfcb25
13
block/qed.c
13
block/qed.c
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@ -377,18 +377,6 @@ static void bdrv_qed_attach_aio_context(BlockDriverState *bs,
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}
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}
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static void bdrv_qed_drain(BlockDriverState *bs)
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{
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BDRVQEDState *s = bs->opaque;
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/* Cancel timer and start doing I/O that were meant to happen as if it
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* fired, that way we get bdrv_drain() taking care of the ongoing requests
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* correctly. */
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qed_cancel_need_check_timer(s);
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qed_plug_allocating_write_reqs(s);
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bdrv_aio_flush(s->bs, qed_clear_need_check, s);
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}
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static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
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Error **errp)
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{
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@ -1694,7 +1682,6 @@ static BlockDriver bdrv_qed = {
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.bdrv_check = bdrv_qed_check,
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.bdrv_detach_aio_context = bdrv_qed_detach_aio_context,
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.bdrv_attach_aio_context = bdrv_qed_attach_aio_context,
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.bdrv_drain = bdrv_qed_drain,
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};
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static void bdrv_qed_init(void)
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