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From: "Richard W.M. Jones" <rjones@redhat.com>
To: Hanna Reitz <hreitz@redhat.com>
Cc: kwolf@redhat.com, andrey.shinkevich@virtuozzo.com,
	eblake@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org
Subject: Re: Block alignment of qcow2 compress driver
Date: Fri, 28 Jan 2022 11:56:19 +0000	[thread overview]
Message-ID: <20220128115619.GR1127@redhat.com> (raw)
In-Reply-To: <e07b998f-9a62-7587-0526-bf51eae54ed6@redhat.com>


I hacked nbdcopy to ignore block alignment (the error actually comes
from libnbd refusing to send the unaligned request, not from
qemu-nbd), and indeed qemu-nbd accepts the unaligned request without
complaint.

Eric - maybe having some flag for nbdcopy to ignore unaligned requests
when we know the server doesn't care (qemu-nbd) would work?

Rich.

--- a/copy/nbd-ops.c
+++ b/copy/nbd-ops.c
@@ -59,6 +59,10 @@ open_one_nbd_handle (struct rw_nbd *rwn)
     exit (EXIT_FAILURE);
   }
 
+  uint32_t sm = nbd_get_strict_mode (nbd);
+  sm &= ~LIBNBD_STRICT_ALIGN;
+  nbd_set_strict_mode (nbd, sm);
+
   nbd_set_debug (nbd, verbose);
 
   if (extents && rwn->d == READING &&


-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW



  parent reply	other threads:[~2022-01-28 12:28 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-28 11:07 Block alignment of qcow2 compress driver Richard W.M. Jones
2022-01-28 11:39 ` Hanna Reitz
2022-01-28 11:48   ` Richard W.M. Jones
2022-01-28 11:57     ` Hanna Reitz
2022-01-28 12:18       ` Richard W.M. Jones
2022-01-28 12:30         ` Hanna Reitz
2022-01-28 13:19           ` Kevin Wolf
2022-01-28 13:36             ` Richard W.M. Jones
2022-01-28 13:30           ` Richard W.M. Jones
2022-01-28 13:37             ` Richard W.M. Jones
2022-01-28 21:22             ` Eric Blake
2022-01-28 11:56   ` Richard W.M. Jones [this message]
2022-01-28 21:40     ` Eric Blake
2022-02-01 14:13 ` Vladimir Sementsov-Ogievskiy

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