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Lunev" Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , Andrey Drobyshev Subject: Re: [PATCH 13/13] iotests/298: cover the preallocation races Message-ID: References: <20260930165000.303236-1-den@openvz.org> <20260930165000.303236-14-den@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260930165000.303236-14-den@openvz.org> User-Agent: NeoMutt/20260616 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.24, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Sep 30, 2026 at 06:49:59PM +0200, Denis V. Lunev wrote: > From: Denis V. Lunev > > Three cases the filter has to get right, all deterministic: a write the > preallocation cannot reach goes through without waiting for it, a write > into the range it covers does not, and a write zeroes over data written > inside that range is not skipped as already zero. > > The second one cannot wait for the write to finish, because that is > what it is checking does not happen, and the data survives either way: > a preallocation that finds the write still in flight gives up. It asks > whether the write got past the filter at all instead, by leaving a > breakpoint below it. > > Signed-off-by: Denis V. Lunev > CC: Kevin Wolf > CC: Hanna Reitz > CC: Vladimir Sementsov-Ogievskiy > CC: Andrey Drobyshev > --- > tests/qemu-iotests/298 | 64 ++++++++++++++++++++++++++++++++++++++ > tests/qemu-iotests/298.out | 4 +-- > 2 files changed, 66 insertions(+), 2 deletions(-) > Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. 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