Hi Qu,
On Fri, 9 Dec 2022 14:05:10 +0800, Qu Wenruo wrote:
> [BUG]
> The latest misc-next tree will make test case btrfs/220 fail with the
> following error messages:
>
> btrfs/220 15s ... - output mismatch (see ~/xfstests/results//btrfs/220.out.bad)
> --- tests/btrfs/220.out 2022-05-11 09:55:30.749999997 +0800
> +++ ~/xfstests/results//btrfs/220.out.bad 2022-12-09 13:57:23.706666671 +0800
> @@ -1,2 +1,5 @@
> QA output created by 220
> +Unexepcted mount options, checking for 'rw,relatime,discard=async,space_cache=v2,subvolid=5,subvol=/' in 'rw,relatime,space_cache=v2,subvolid=5,subvol=/' using 'nodiscard'
> +Unexepcted mount options, checking for 'rw,relatime,discard=async,space_cache=v2,subvolid=5,subvol=/' in 'rw,relatime,space_cache=v2,subvolid=5,subvol=/' using 'nodiscard'
> +Unexepcted mount options, checking for 'rw,relatime,discard=async,space_cache=v2,subvolid=5,subvol=/' in 'rw,relatime,space_cache=v2,subvolid=5,subvol=/' using 'nodiscard'
> Silence is golden
> ...
> (Run 'diff -u ~/xfstests/tests/btrfs/220.out ~/xfstests/results//btrfs/220.out.bad' to see the entire diff)
> Ran: btrfs/220
> Failures: btrfs/220
> Failed 1 of 1 tests
>
> [CAUSE]
> Since patch "btrfs: auto enable discard=async when possible", which is
> already in the maintainer's tree for next merge window, btrfs will
> automatically enable asynchronous discard for devices which supports
> discard.
>
> This makes our $DEFAULT_OPTS to have "discard=async" in it.
>
> While for "nodiscard" mount option, we will completely disable all
> discard, causing the above mismatch.
>
> [FIX]
> Fix it by introducing $DEFAULT_NODISCARD_OPTS specifically for
> "nodiscard" mount option.
>
> If async discard is not enabled by default, $DEFAULT_NODISCARD_OPTS will
> be the same as $DEFAULT_OPTS, thus everything would work as usual.
>
> If async discard is enabled by default, $DEFAULT_NODISCARD_OPTS will
> have that removed, so for "nodiscard" we can use $DEFAULT_NODISCARD_OPTS
> as expected mount options.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> ---
> tests/btrfs/220 | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/tests/btrfs/220 b/tests/btrfs/220
> index 4d94ccd6..30ca06f6 100755
> --- a/tests/btrfs/220
> +++ b/tests/btrfs/220
> @@ -280,10 +280,10 @@ test_revertible_options()
> if [ "$enable_discard_sync" = true ]; then
> test_roundtrip_mount "discard" "discard" "discard=sync" "discard"
> test_roundtrip_mount "discard=async" "discard=async" "discard=sync" "discard"
> - test_roundtrip_mount "discard=sync" "discard" "nodiscard" "$DEFAULT_OPTS"
> + test_roundtrip_mount "discard=sync" "discard" "nodiscard" "$DEFAULT_NODISCARD_OPTS"
> else
> test_roundtrip_mount "discard" "discard" "discard" "discard"
> - test_roundtrip_mount "discard" "discard" "nodiscard" "$DEFAULT_OPTS"
> + test_roundtrip_mount "discard" "discard" "nodiscard" "$DEFAULT_NODISCARD_OPTS"
> fi
>
> test_roundtrip_mount "enospc_debug" "enospc_debug" "noenospc_debug" "$DEFAULT_OPTS"
> @@ -344,6 +344,12 @@ _scratch_mount
> DEFAULT_OPTS=$(cat /proc/self/mounts | grep $SCRATCH_MNT | \
> $AWK_PROG '{ print $4 }')
>
> +# Since 63a7cb130718 ("btrfs: auto enable discard=async when possible"),
> +# "discard=async" will be automatically enabled if the device supports.
> +# This can screw up our test against nodiscard options, thus remove the
> +# default "discard=async" mount option for "nodiscard" tests.
> +DEFAULT_NODISCARD_OPTS=$(echo -n "$DEFAULT_OPTS" | $SED_PROG 's/,discard=async//')
Comma placement here looks a little fragile, but I suppose discard won't
normally be listed first.
FWIW, substring removal is also possible in plain bash e.g.:
DEFAULT_NODISCARD_OPTS="${DEFAULT_OPTS/,discard=async/}"
Either way...
Reviewed-by: David Disseldorp <ddiss@xxxxxxx>
> +
> $BTRFS_UTIL_PROG subvolume create "$SCRATCH_MNT/vol1" > /dev/null
> touch "$SCRATCH_MNT/vol1/file.txt"
> _scratch_unmount
