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Date:   Wed, 6 Apr 2022 15:54:24 -0400
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: sporadic hangs on generic/186
Message-ID: <20220406195424.GA1242@fieldses.org>
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From:   bfields@fieldses.org (J. Bruce Fields)
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In the last couple days I've started getting hangs on xfstests
generic/186 on upstream.  I also notice the test completes after 10+
hours (usually it takes about 5 minutes).  Sometimes this is accompanied
by "nfs: RPC call returned error 12" on the client.

Test description is:

# Ensuring that copy on write in buffered mode works when free space
# is heavily fragmented.
#   - Create two files
#   - Reflink the odd blocks of the first file into a third file.
#   - Reflink the even blocks of the second file into the third file.
#   - Try to fragment the free space by allocating a huge file and
#     punching out every other block.
#   - CoW across the halfway mark.
#   - Check that the files are now different where we say they're
#   different.

so maybe it's really some xfs change, I don't know.  Or maybe it's a
problem with my particular test filesystem (which doesn't get recreated
for each test run).

The problem doesn't reproduce easily enough to bisect.

I may just turn off that test for now.

--b.