From: Darrick J. Wong <djwong@xxxxxxxxxx> Once in a very long while, the fallocate calls in this test will fail due to ENOSPC conditions. While in theory this test is careful only to allocate at most 160M of space from a 256M filesystem, there's a twist on XFS: speculative preallocation. The first loop in this test is an 80M appending write done in units of 4k. Once the file size hits 64k, XFS will begin speculatively preallocating blocks past the end of the file; as the file grows larger, so will the speculative preallocation. Since the pwrite/rm loop races with the fallocate/rm loop, it's possible that the fallocate loop will free that file just before the buffered write extends the speculative preallocation out to 160MB. With fs and log overhead, that doesn't leave enough free space to start the 80MB fallocate request, which tries to avoid disappointing the caller by freeing all speculative preallocations. That fails if the pwriter thread owns the IOLOCK on $testfile1, so fallocate returns ENOSPC and the test fails. The simple solution here is to disable speculative preallocation by setting an extent size hint if the fs is XFS. Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> --- tests/generic/371 | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tests/generic/371 b/tests/generic/371 index c94fa85e..a2fdaf7b 100755 --- a/tests/generic/371 +++ b/tests/generic/371 @@ -18,10 +18,18 @@ _begin_fstest auto quick enospc prealloc _supported_fs generic _require_scratch _require_xfs_io_command "falloc" +test "$FSTYP" = "xfs" && _require_xfs_io_command "extsize" _scratch_mkfs_sized $((256 * 1024 * 1024)) >> $seqres.full 2>&1 _scratch_mount +# Disable speculative post-EOF preallocation on XFS, which can grow fast enough +# that a racing fallocate then fails. +if [ "$FSTYP" = "xfs" ]; then + alloc_sz="$(_get_file_block_size $SCRATCH_MNT)" + $XFS_IO_PROG -c "extsize $alloc_sz" $SCRATCH_MNT >> $seqres.full +fi + testfile1=$SCRATCH_MNT/testfile1 testfile2=$SCRATCH_MNT/testfile2
