From: Eric Sandeen <sandeen@sandeen.net>
To: Dave Chinner <david@fromorbit.com>, Todd Gill <tgill@redhat.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: file write that exceeds thin device capacity
Date: Thu, 15 Nov 2018 16:22:51 -0600 [thread overview]
Message-ID: <3759a449-5bc8-5fa8-1a6e-1ecf714c847d@sandeen.net> (raw)
In-Reply-To: <20181113221004.GT19305@dastard>
On 11/13/18 4:10 PM, Dave Chinner wrote:
> On Tue, Nov 13, 2018 at 02:57:18PM -0500, Todd Gill wrote:
>> Hi,
>>
>> This script creates a 1 TB thin device (device mapper) backed by 1 GB
>> of physical space. The script then writes more than 1 GB via
>> $BLOCK_SIZE files to XFS. I'm testing to see if recovery can be
>> automated.
>>
>> https://paste.fedoraproject.org/paste/ropelNyOQWCjk3hfK0jltA
>>
>> When the $BLOCK_SIZE passed to dd is 4k - dd gets an error on the file
>> write that exceeds the physical capacity that backs the thin device.
>> XFS doesn't indicate any problems.
> user data write error.
To put a finer point on this, because it's a user data write error, it
is up to userspace to cope, and xfs isn't going to indicate that it has an
internal error (as it would for metadata writes).
i.e. dd should have seen an error bubbled up, and you
would then know to retry, error handle, take evasive action, etc as you
see fit.
-Eric
prev parent reply other threads:[~2018-11-16 8:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-13 19:57 file write that exceeds thin device capacity Todd Gill
2018-11-13 22:10 ` Dave Chinner
2018-11-15 22:22 ` Eric Sandeen [this message]
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