From: Max Reitz <mreitz@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: david.edmondson@oracle.com, kwolf@redhat.com, qemu-block@nongnu.org
Subject: Re: [PATCH 2/6] block/vdi: Don't assume that blocks are larger than VdiHeader
Date: Wed, 24 Mar 2021 15:25:57 +0100 [thread overview]
Message-ID: <082a32cc-c09e-522d-429d-49a1727c81f5@redhat.com> (raw)
In-Reply-To: <20210317180013.235231-3-pbonzini@redhat.com>
On 17.03.21 19:00, Paolo Bonzini wrote:
> From: David Edmondson <david.edmondson@oracle.com>
>
> Given that the block size is read from the header of the VDI file, a
> wide variety of sizes might be seen. Rather than re-using a block
> sized memory region when writing the VDI header, allocate an
> appropriately sized buffer.
>
> Signed-off-by: David Edmondson <david.edmondson@oracle.com>
> Message-Id: <20210309144015.557477-3-david.edmondson@oracle.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> block/vdi.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/block/vdi.c b/block/vdi.c
> index 2a6dc26124..548f8a057b 100644
> --- a/block/vdi.c
> +++ b/block/vdi.c
> @@ -696,18 +696,20 @@ nonallocating_write:
>
> if (block) {
> /* One or more new blocks were allocated. */
> - VdiHeader *header = (VdiHeader *) block;
> + VdiHeader *header;
> uint8_t *base;
> uint64_t offset;
> uint32_t n_sectors;
>
> + g_free(block);
This logic (checking @block != NULL) was a bit weird before and this
just seems to accomodate it. We probably shouldn’t check @block, but
some boolean, and *block should be freed after the while () loop.
Considering the “if (block)” was there already and it’d be weird to keep
that check if *block were freed by that point, I suppose this isn’t
making it worse, though, so:
Reviewed-by: Max Reitz <mreitz@redhat.com>
> + header = g_malloc(sizeof(*header));
> +
> logout("now writing modified header\n");
> assert(VDI_IS_ALLOCATED(bmap_first));
> *header = s->header;
> vdi_header_to_le(header);
> - ret = bdrv_pwrite(bs->file, 0, block, sizeof(VdiHeader));
> - g_free(block);
> - block = NULL;
> + ret = bdrv_pwrite(bs->file, 0, header, sizeof(*header));
> + g_free(header);
>
> if (ret < 0) {
> return ret;
>
next prev parent reply other threads:[~2021-03-24 14:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 18:00 [PATCH v5 0/6] coroutine rwlock downgrade fix, minor VDI changes Paolo Bonzini
2021-03-17 18:00 ` [PATCH 1/6] block/vdi: When writing new bmap entry fails, don't leak the buffer Paolo Bonzini
2021-03-24 14:25 ` Max Reitz
2021-03-17 18:00 ` [PATCH 2/6] block/vdi: Don't assume that blocks are larger than VdiHeader Paolo Bonzini
2021-03-24 14:25 ` Max Reitz [this message]
2021-03-17 18:00 ` [PATCH 3/6] coroutine/mutex: Store the coroutine in the CoWaitRecord only once Paolo Bonzini
2021-03-17 18:00 ` [PATCH 4/6] coroutine-lock: reimplement CoRwlock to fix downgrade bug Paolo Bonzini
2021-03-24 16:15 ` Stefan Hajnoczi
2021-03-24 16:40 ` Paolo Bonzini
2021-03-17 18:00 ` [PATCH 5/6] test-coroutine: add rwlock upgrade test Paolo Bonzini
2021-03-17 18:19 ` David Edmondson
2021-03-17 18:00 ` [PATCH 6/6] test-coroutine: Add rwlock downgrade test Paolo Bonzini
2021-03-24 14:26 ` [PATCH v5 0/6] coroutine rwlock downgrade fix, minor VDI changes Max Reitz
2021-03-24 16:23 ` Stefan Hajnoczi
2021-03-24 16:43 ` Paolo Bonzini
-- strict thread matches above, loose matches on Subject: below --
2021-03-17 12:16 [PATCH v4 " Paolo Bonzini
2021-03-17 12:16 ` [PATCH 2/6] block/vdi: Don't assume that blocks are larger than VdiHeader Paolo Bonzini
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