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From: Milan Broz <gmazyland@gmail.com>
To: linux-block <linux-block@vger.kernel.org>
Cc: Ondrej Kozina <okozina@redhat.com>
Subject: Errors in log with WRITE_ZEROES over loop on NFS
Date: Wed, 27 Jul 2022 15:01:25 +0200	[thread overview]
Message-ID: <975ea807-667d-3ef3-b3e2-26b22ea74029@gmail.com> (raw)

Hi,

We switched to using BLKZEROOUT ioctl in libcryptsetup, and now we see a lot of messages like

  : operation not supported error, dev loop1, sector 0 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0

But the operation succeeds (ioctl returns 0).

As it seems, this happens when a loop device is allocated over a file on NFS mounted directory.
Easy to reproduce (5.19-rc8) by doing this in NFS mounted dir:

  # truncate -s 1M test.img
  # losetup /dev/loop1 test.img
  # fallocate -zn -l 1048576 /dev/loop1


Shouldn't the block layer be quiet here and just switch to a different wipe method?
(I think it happens in other cases.)

It is perhaps just a benign message, but it can trigger some reports.

Milan


             reply	other threads:[~2022-07-27 13:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 13:01 Milan Broz [this message]
2022-07-27 21:37 ` Errors in log with WRITE_ZEROES over loop on NFS Chaitanya Kulkarni
2022-07-28 11:48   ` Milan Broz

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