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Re: [Qemu-devel] [PATCH] block: Update image size in bdrv_invalidate_cac
From: |
Benoît Canet |
Subject: |
Re: [Qemu-devel] [PATCH] block: Update image size in bdrv_invalidate_cache() |
Date: |
Tue, 11 Mar 2014 17:41:45 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
The Tuesday 11 Mar 2014 à 10:58:39 (+0100), Kevin Wolf wrote :
> After migration has completed, we call bdrv_invalidate_cache() so that
> drivers which cache some data drop their stale copy of the data and
> reread it from the image file to get a new version of data that the
> source modified while the migration was running.
>
> Reloading metadata from the image file is useless, though, if the size
> of the image file stays stale (this is a value that is cached for all
> image formats in block.c). Reads from (meta)data after the old EOF
> return only zeroes, causing image corruption.
>
> We need to update bs->total_sectors in all layers that could potentially
> have changed their size (i.e. backing files are not a concern - if they
> are changed, we're in bigger trouble)
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> block.c | 10 +++++++++-
> block/qcow2.c | 2 ++
> block/qed.c | 3 +++
> 3 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/block.c b/block.c
> index f1ef4b0..7b306fb 100644
> --- a/block.c
> +++ b/block.c
> @@ -4776,9 +4776,17 @@ flush_parent:
>
> void bdrv_invalidate_cache(BlockDriverState *bs)
> {
> - if (bs->drv && bs->drv->bdrv_invalidate_cache) {
> + if (!bs->drv) {
> + return;
> + }
> +
> + if (bs->drv->bdrv_invalidate_cache) {
> bs->drv->bdrv_invalidate_cache(bs);
> + } else if (bs->file) {
> + bdrv_invalidate_cache(bs->file);
> }
> +
> + refresh_total_sectors(bs, bs->total_sectors);
> }
>
> void bdrv_invalidate_cache_all(void)
> diff --git a/block/qcow2.c b/block/qcow2.c
> index cfe80be..b5b1e8c 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1176,6 +1176,8 @@ static void qcow2_invalidate_cache(BlockDriverState *bs)
>
> qcow2_close(bs);
>
> + bdrv_invalidate_cache(bs->file);
> +
> options = qdict_new();
> qdict_put(options, QCOW2_OPT_LAZY_REFCOUNTS,
> qbool_from_int(s->use_lazy_refcounts));
> diff --git a/block/qed.c b/block/qed.c
> index 8802ad3..837accd 100644
> --- a/block/qed.c
> +++ b/block/qed.c
> @@ -1563,6 +1563,9 @@ static void bdrv_qed_invalidate_cache(BlockDriverState
> *bs)
> BDRVQEDState *s = bs->opaque;
>
> bdrv_qed_close(bs);
> +
> + bdrv_invalidate_cache(bs->file);
> +
> memset(s, 0, sizeof(BDRVQEDState));
> bdrv_qed_open(bs, NULL, bs->open_flags, NULL);
> }
> --
> 1.8.1.4
>
>
I have the impression that you are silently fixing other nits;
However:
Reviewed-by: Benoit Canet <address@hidden>