Re: [dm-devel] [PATCH 01/27] target: remove an incorrect unmap zeroes data deduction
- To: Christoph Hellwig <hch@lst.de>
- Cc: Jens Axboe <axboe@kernel.dk>, jfs-discussion@lists.sourceforge.net, linux-nvme@lists.infradead.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, dm-devel@redhat.com, target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, drbd-dev@lists.linbit.com, linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi@vger.kernel.org, cluster-devel@redhat.com, xen-devel@lists.xenproject.org, linux-ext4@vger.kernel.org, linux-um@lists.infradead.org, nbd@other.debian.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, ceph-devel@vger.kernel.org, linux-raid@vger.kernel.org, linux-mmc@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, ntfs3@lists.linux.dev, linux-btrfs@vger.kernel.org
- Subject: Re: [dm-devel] [PATCH 01/27] target: remove an incorrect unmap zeroes data deduction
- From: "Martin K. Petersen" <martin.petersen@oracle.com>
- Date: Wed, 06 Apr 2022 23:06:16 -0400
- Message-id: <[🔎] yq1r169k2xu.fsf@ca-mkp.ca.oracle.com>
- In-reply-to: <[🔎] 20220406060516.409838-2-hch@lst.de> (Christoph Hellwig's message of "Wed, 6 Apr 2022 08:04:50 +0200")
- References: <[🔎] 20220406060516.409838-1-hch@lst.de> <[🔎] 20220406060516.409838-2-hch@lst.de>
Christoph,
> For block devices the target code implements UNMAP as calls to
> blkdev_issue_discard, which does not guarantee zeroing just because
> Write Zeroes is supported.
>
> Note that this does not affect the file backed path which uses
> fallocate to punch holes.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
--
Martin K. Petersen Oracle Linux Engineering
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