On Mon, Jan 03, 2022 at 06:04:17PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> This test checks that speculative file preallocations are transferred to
> threads writing other files when space is low. Since we have background
> threads to clear those preallocations, it's possible that the test
> program might not get a speculative preallocation on the first try.
>
> This problem has become more pronounced since the introduction of
> background inode inactivation since userspace no longer has direct
> control over the timing of file blocks being released from unlinked
> files. As a result, the author has seen an increase in sporadic
> warnings from this test about speculative preallocations not appearing.
>
> Therefore, modify the function to try up to five times to create the
> speculative preallocation before emitting warnings that then cause
> golden output failures.
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> ---
> tests/xfs/014 | 41 +++++++++++++++++++++++++----------------
> 1 file changed, 25 insertions(+), 16 deletions(-)
>
> diff --git a/tests/xfs/014 b/tests/xfs/014
> index a605b359..1f0ebac3 100755
> --- a/tests/xfs/014
> +++ b/tests/xfs/014
> @@ -33,27 +33,36 @@ _cleanup()
> # failure.
> _spec_prealloc_file()
> {
> - file=$1
> + local file=$1
> + local prealloc_size=0
> + local i=0
>
> - rm -f $file
> + # Now that we have background garbage collection processes that can be
> + # triggered by low space/quota conditions, it's possible that we won't
> + # succeed in creating a speculative preallocation on the first try.
> + for ((tries = 0; tries < 5 && prealloc_size == 0; tries++)); do
> + rm -f $file
>
> - # a few file extending open-write-close cycles should be enough to
> - # trigger the fs to retain preallocation. write 256k in 32k intervals to
> - # be sure
> - for i in $(seq 0 32768 262144); do
> - $XFS_IO_PROG -f -c "pwrite $i 32k" $file >> $seqres.full
> + # a few file extending open-write-close cycles should be enough
> + # to trigger the fs to retain preallocation. write 256k in 32k
> + # intervals to be sure
> + for i in $(seq 0 32768 262144); do
> + $XFS_IO_PROG -f -c "pwrite $i 32k" $file >> $seqres.full
> + done
> +
> + # write a 4k aligned amount of data to keep the calculations
> + # simple
> + $XFS_IO_PROG -c "pwrite 0 128m" $file >> $seqres.full
> +
> + size=`_get_filesize $file`
> + blocks=`stat -c "%b" $file`
> + blocksize=`stat -c "%B" $file`
> +
> + prealloc_size=$((blocks * blocksize - size))
So we only try same pwrite operations 5 times, and only check the prealloc_size after 5
times done? Should we break from this loop once prealloc_size > 0?
Thanks,
Zorro
> done
>
> - # write a 4k aligned amount of data to keep the calculations simple
> - $XFS_IO_PROG -c "pwrite 0 128m" $file >> $seqres.full
> -
> - size=`_get_filesize $file`
> - blocks=`stat -c "%b" $file`
> - blocksize=`stat -c "%B" $file`
> -
> - prealloc_size=$((blocks * blocksize - size))
> if [ $prealloc_size -eq 0 ]; then
> - echo "Warning: No speculative preallocation for $file." \
> + echo "Warning: No speculative preallocation for $file after $tries iterations." \
> "Check use of the allocsize= mount option."
> fi
>
>
