On Thu, Sep 19, 2019 at 11:00:24PM +0800, Zorro Lang wrote:
> xfs/030 always fails after d0e484ac699f ("check: wipe scratch devices
> between tests") get merged.
>
> Due to xfs/030 does a sized(100m) mkfs. Before we merge above commit,
> mkfs.xfs detects an old primary superblock, it will write zeroes to
> all superblocks before formatting the new filesystem. But this won't
> be done if we wipe the first superblock(by merging above commit).
>
> That means if we make a (smaller) sized xfs after wipefs, those *old*
> superblocks which created by last time mkfs.xfs will be left on disk.
One thing missing from this patch -- if the test formatted the scratch
device with non-default geometry, the backup superblocks from that
filesystem will not be erased. Going back to my example from the email
thread, if the scratch disk has:
SB0 [16M zeroes] SB1 [16M zeroes] <4 more AGs> <zeroes from 100M to 1G> \
SB'1 [1G space] SB'2 [1G space] SB'3 [1G space]
Where SB[0-5] are the ones written by xfs/030 and SB'[1-3] were written
by a previous test that did the default scratch device mkfs, then this
patch will wipe out SB'[1-3] and SB0:
000 [16M zeroes] SB1 [16M zeroes] <4 more AGs> <zeroes from 100M to 1G> \
0000 [1G space] 0000 [1G space] 0000 [1G space]
But that still leaves SB[1-5] which xfs_repair could stumble over later.
For example, if the next test to be run formats a filesystem with 24MB
AGs (instead of 16) and zaps the superblock, then repair will eventually
try a linear scan looking for superblocks and find the ones from the
16MB filesystem first.
There isn't a sequence of tests that do this, but so long as we're
fixing this we might as well zap as much as we can. So I propose adding
to try_wipe_scratch_xfs() the following:
dbsize=
_scratch_xfs_db -c 'sb 0' -c 'p blocksize agblocks agcount' 2>&1 | \
sed -e 's/ = /=/g' -e 's/blocksize/dbsize/g' \
-e 's/agblocks/agsize/g' > $tmp.mkfs
. $tmp.mkfs
and then repeat the for loop. If there isn't a filesystem then
$tmp.mkfs will be an empty file and the loop won't run.
> Then when we do xfs_repair, if xfs_repair can't find the first SB, it
> will go to find those *old* SB at first. When it finds them,
> everyting goes wrong.
>
> So I try to get XFS AG geometry(by default) and then try to erase all
> superblocks. Thanks Darrick J. Wong helped to analyze this issue.
>
> Signed-off-by: Zorro Lang <zlang@xxxxxxxxxx>
> ---
> common/rc | 4 ++++
> common/xfs | 23 +++++++++++++++++++++++
> 2 files changed, 27 insertions(+)
>
> diff --git a/common/rc b/common/rc
> index 66c7fd4d..fe13f659 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -4048,6 +4048,10 @@ _try_wipe_scratch_devs()
> for dev in $SCRATCH_DEV_POOL $SCRATCH_DEV $SCRATCH_LOGDEV $SCRATCH_RTDEV; do
> test -b $dev && $WIPEFS_PROG -a $dev
> done
> +
> + if [ "$FSTYP" = "xfs" ];then
> + try_wipe_scratch_xfs
> + fi
We probably ought to delegate all wiping to try_wipe_scratch_xfs, i.e.:
test -b $dev || continue
case "$FSTYP" in
"xfs")
_try_wipe_scratch_xfs
;;
*)
$WIPEFS_PROG -a $dev
;;
esac
and add the WIPEFS_PROG call to _try_wipe_scratch_xfs.
> }
>
> # Only run this on xfs if xfs_scrub is available and has the unicode checker
> diff --git a/common/xfs b/common/xfs
> index 1bce3c18..34516f82 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -884,3 +884,26 @@ _xfs_mount_agcount()
> {
> $XFS_INFO_PROG "$1" | grep agcount= | sed -e 's/^.*agcount=\([0-9]*\),.*$/\1/g'
> }
> +
> +# wipe the superblock of each XFS AGs
> +try_wipe_scratch_xfs()
Common helper functions should start with a '_'
> +{
> + local tmp=`mktemp -u`
> +
> + _scratch_mkfs_xfs -N 2>/dev/null | perl -ne '
> + if (/^meta-data=.*\s+agcount=(\d+), agsize=(\d+) blks/) {
> + print STDOUT "agcount=$1\nagsize=$2\n";
> + }
> + if (/^data\s+=\s+bsize=(\d+)\s/) {
> + print STDOUT "dbsize=$1\n";
> + }' > $tmp.mkfs
> +
> + . $tmp.mkfs
> + if [ -n "$agcount" -a -n "$agsize" -a -n "$dbsize" ];then
> + for ((i = 0; i < agcount; i++)); do
> + $XFS_IO_PROG -c "pwrite $((i * dbsize * agsize)) $dbsize" \
> + $SCRATCH_DEV >/dev/null;
> + done
> + fi
> + rm -f $tmp.mkfs
Add code as discussed above.
--D
> +}
> --
> 2.20.1
>
