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Re: [Qemu-devel] [PATCH 3/5] block: convert bdrv_invalidate_cache callba
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH 3/5] block: convert bdrv_invalidate_cache callback to coroutine_fn |
Date: |
Tue, 11 Jul 2017 10:24:51 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 10.07.2017 um 18:58 hat Paolo Bonzini geschrieben:
> QED's bdrv_invalidate_cache implementation would like to reuse functions
> that acquire/release the metadata locks. Call it from coroutine context
> to simplify the logic.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index b5de67d113..4ff7e89009 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1854,7 +1854,8 @@ static void qcow2_close(BlockDriverState *bs)
> qcow2_free_snapshots(bs);
> }
>
> -static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
> +static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
> + Error **errp)
> {
> BDRVQcow2State *s = bs->opaque;
> int flags = s->flags;
> @@ -1877,7 +1878,9 @@ static void qcow2_invalidate_cache(BlockDriverState
> *bs, Error **errp)
> options = qdict_clone_shallow(bs->options);
>
> flags &= ~BDRV_O_INACTIVE;
> + qemu_co_mutex_lock(&s->lock);
> ret = qcow2_do_open(bs, options, flags, &local_err);
> + qemu_co_mutex_unlock(&s->lock);
> QDECREF(options);
> if (local_err) {
> error_propagate(errp, local_err);
How useful is this lock really? If we expect any requests while this
function is running (we don't, it would break horribly), it should
probably cover qcow2_close(), too.
Or maybe the cleaner way would be bdrv_drained_begin/end() around
everything directly in bdrv_co_invalidate_cache().
Kevin
[Qemu-devel] [PATCH 3/5] block: convert bdrv_invalidate_cache callback to coroutine_fn, Paolo Bonzini, 2017/07/10
- Re: [Qemu-devel] [PATCH 3/5] block: convert bdrv_invalidate_cache callback to coroutine_fn,
Kevin Wolf <=
[Qemu-devel] [PATCH 4/5] qcow2: introduce qcow2_write_caches and qcow2_flush_caches, Paolo Bonzini, 2017/07/10
[Qemu-devel] [PATCH 2/5] qed: make bdrv_qed_do_open a coroutine_fn, Paolo Bonzini, 2017/07/10
[Qemu-devel] [PATCH 5/5] block: convert bdrv_check callback to coroutine_fn, Paolo Bonzini, 2017/07/10