Re: [PATCH 2/3] fstests: btrfs/14[23]: Use proper help to get both devid and physical offset for corruption.

Filipe Manana
2019-12-17T17:31:00Z

On Wed, Dec 11, 2019 at 10:41 AM Qu Wenruo <wqu@suse.com> wrote:
>
> [BUG]
> When using btrfs-progs v5.4, btrfs/142 and btrfs/143 will fail:
> btrfs/142 1s ... - output mismatch (see xfstests/results//btrfs/142.out.bad)
> --- tests/btrfs/142.out 2018-09-16 21:30:48.505104287 +0100
> +++ xfstests/results//btrfs/142.out.bad
> 2019-12-10 15:35:40.280392626 +0000
> @@ -3,37 +3,37 @@
> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> wrote 65536/65536 bytes
> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> -XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> ...
> (Run 'diff -u xfstests/tests/btrfs/142.out xfstests/results//btrfs/142.out.bad' to see the entire diff)
>
> [CAUSE]
> Btrfs/14[23] test whether a read on corrupted stripe will re-silver
> itself.
> Such test by its nature will need to modify on-disk data, thus need to
> get the btrfs logical -> physical mapping, which is done by near
> hard-coded lookup function, which rely on certain stripe:devid sequence.
>
> Recent btrfs-progs commit c501c9e3b816 ("btrfs-progs: mkfs: match devid
> order to the stripe index") changes how we use devices in mkfs.btrfs,
> this caused a change in chunk layout, and break the hard-coded
> stripe:devid sequence.
>
> [FIX]
> This patch will do full devid and physical offset lookup, instead of old
> physical offset only lookup.
>
> The only assumption made is, mkfs.btrfs assigns devid sequentially for
> its devices.
> Which means, for "mkfs.btrfs $dev1 $dev2 $dev3", we get devid 1 for $dev1,
> devid 2 for $dev2, and so on.
>
> This change will allow btrfs/14[23] to handle even future chunk layout
> change. (Although I hope this will never happen again).
>
> This also addes extra debug output (although less than 10 lines) into
> $seqres.full, just in case when layout changes and current lookup can't
> handle it, developer can still pindown the problem easily.
>
> Reported-by: Filipe Manana <fdmanana@suse.com>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> tests/btrfs/142 | 50 +++++++++++++++++++++++++++++++--------------
> tests/btrfs/142.out | 2 --
> tests/btrfs/143 | 48 +++++++++++++++++++++++++++++++------------
> tests/btrfs/143.out | 2 --
> 4 files changed, 70 insertions(+), 32 deletions(-)
>
> diff --git a/tests/btrfs/142 b/tests/btrfs/142
> index a23fe1bf..9c037ff6 100755
> --- a/tests/btrfs/142
> +++ b/tests/btrfs/142
> @@ -47,30 +47,45 @@ _require_command "$FILEFRAG_PROG" filefrag
>
> get_physical()
> {
> - # $1 is logical address
> - # print chunk tree and find devid 2 which is $SCRATCH_DEV
> + local logical=$1
> + local stripe=$2
> $BTRFS_UTIL_PROG inspect-internal dump-tree -t 3 $SCRATCH_DEV | \
> - grep $1 -A 6 | awk '($1 ~ /stripe/ && $3 ~ /devid/ && $4 ~ /1/) { print $6 }'
> + grep $logical -A 6 | \
> + awk "(\$1 ~ /stripe/ && \$3 ~ /devid/ && \$2 ~ /$stripe/) { print \$6 }"

Should use $AWK_PROG instead of direct call to 'awk'.

> }
>
> +get_devid()
> +{
> + local logical=$1
> + local stripe=$2
> + $BTRFS_UTIL_PROG inspect-internal dump-tree -t 3 $SCRATCH_DEV | \
> + grep $logical -A 6 | \
> + awk "(\$1 ~ /stripe/ && \$3 ~ /devid/ && \$2 ~ /$stripe/) { print \$4 }"

Same here.

> +}
>
> -SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
> +get_device_path()
> +{
> + local devid=$1
> + echo "$SCRATCH_DEV_POOL" | awk "{print \$$devid}"
> +}
>
> start_fail()
> {
> + local sysfs_bdev="$1"
> echo 100 > $DEBUGFS_MNT/fail_make_request/probability
> echo 2 > $DEBUGFS_MNT/fail_make_request/times
> echo 1 > $DEBUGFS_MNT/fail_make_request/task-filter
> echo 0 > $DEBUGFS_MNT/fail_make_request/verbose
> - echo 1 > $SYSFS_BDEV/make-it-fail
> + echo 1 > $sysfs_bdev/make-it-fail
> }
>
> stop_fail()
> {
> + local sysfs_bdev="$1"
> echo 0 > $DEBUGFS_MNT/fail_make_request/probability
> echo 0 > $DEBUGFS_MNT/fail_make_request/times
> echo 0 > $DEBUGFS_MNT/fail_make_request/task-filter
> - echo 0 > $SYSFS_BDEV/make-it-fail
> + echo 0 > $sysfs_bdev/make-it-fail
> }
>
> _scratch_dev_pool_get 2
> @@ -87,17 +102,23 @@ _scratch_mount -o nospace_cache,nodatasum
> $XFS_IO_PROG -f -d -c "pwrite -S 0xaa -b 128K 0 128K" "$SCRATCH_MNT/foobar" |\
> _filter_xfs_io_offset
>
> -# step 2, corrupt the first 64k of one copy (on SCRATCH_DEV which is the first
> -# one in $SCRATCH_DEV_POOL
> +# step 2, corrupt the first 64k of stripe #1
> echo "step 2......corrupt file extent" >>$seqres.full
>
> ${FILEFRAG_PROG} -v $SCRATCH_MNT/foobar >> $seqres.full
> logical_in_btrfs=`${FILEFRAG_PROG} -v $SCRATCH_MNT/foobar | _filter_filefrag | cut -d '#' -f 1`
> -physical_on_scratch=`get_physical ${logical_in_btrfs}`
> +physical=`get_physical ${logical_in_btrfs} 1`
> +devid=$(get_devid ${logical_in_btrfs} 1)
> +target_dev=$(get_device_path $devid)
> +
> +SYSFS_BDEV=`_sysfs_dev $target_dev`
>
> _scratch_unmount
> -$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 64K $physical_on_scratch 64K" $SCRATCH_DEV |\
> - _filter_xfs_io_offset
> +$BTRFS_UTIL_PROG ins dump-tree -t 3 $SCRATCH_DEV | \
> + grep $logical_in_btrfs -A 6 >> $seqres.full
> +echo "Corrupt stripe 1 devid $devid devpath $target_dev physical $physical" \
> + >> $seqres.full
> +$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 64K $physical 64K" $target_dev > /dev/null
>
> _scratch_mount -o nospace_cache
>
> @@ -106,8 +127,7 @@ echo "step 3......repair the bad copy" >>$seqres.full
>
> # since raid1 consists of two copies, and the bad copy was put on stripe #1
> # while the good copy lies on stripe #0, the bad copy only gets access when the
> -# reader's pid % 2 == 1 is true
> -start_fail
> +start_fail $SYSFS_BDEV
> while [[ -z ${result} ]]; do
> # enable task-filter only fails the following dio read so the repair is
> # supposed to work.
> @@ -117,12 +137,12 @@ while [[ -z ${result} ]]; do
> exec $XFS_IO_PROG -d -c \"pread -b 128K 0 128K\" \"$SCRATCH_MNT/foobar\"
> fi");
> done
> -stop_fail
> +stop_fail $SYSFS_BDEV
>
> _scratch_unmount
>
> # check if the repair works
> -$XFS_IO_PROG -c "pread -v -b 512 $physical_on_scratch 512" $SCRATCH_DEV |\
> +$XFS_IO_PROG -c "pread -v -b 512 $physical 512" $target_dev | \
> _filter_xfs_io_offset
>
> _scratch_dev_pool_put
> diff --git a/tests/btrfs/142.out b/tests/btrfs/142.out
> index 0f32ffbe..2e22f292 100644
> --- a/tests/btrfs/142.out
> +++ b/tests/btrfs/142.out
> @@ -1,8 +1,6 @@
> QA output created by 142
> wrote 131072/131072 bytes
> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -wrote 65536/65536 bytes
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> diff --git a/tests/btrfs/143 b/tests/btrfs/143
> index 91af52f9..b2ffeb63 100755
> --- a/tests/btrfs/143
> +++ b/tests/btrfs/143
> @@ -54,30 +54,48 @@ _require_command "$FILEFRAG_PROG" filefrag
>
> get_physical()
> {
> - # $1 is logical address
> - # print chunk tree and find devid 2 which is $SCRATCH_DEV
> + local logical=$1
> + local stripe=$2
> $BTRFS_UTIL_PROG inspect-internal dump-tree -t 3 $SCRATCH_DEV | \
> - grep $1 -A 6 | awk '($1 ~ /stripe/ && $3 ~ /devid/ && $4 ~ /1/) { print $6 }'
> + grep $logical -A 6 | \
> + awk "(\$1 ~ /stripe/ && \$3 ~ /devid/ && \$2 ~ /$stripe/) { print \$6 }"

Same here.

> +}
> +
> +get_devid()
> +{
> + local logical=$1
> + local stripe=$2
> + $BTRFS_UTIL_PROG inspect-internal dump-tree -t 3 $SCRATCH_DEV | \
> + grep $logical -A 6 | \
> + awk "(\$1 ~ /stripe/ && \$3 ~ /devid/ && \$2 ~ /$stripe/) { print \$4 }"

Same here.

> +}
> +
> +get_device_path()
> +{
> + local devid=$1
> + echo "$SCRATCH_DEV_POOL" | awk "{print \$$devid}"
> }
>
> SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
>
> start_fail()
> {
> + local sysfs_bdev="$1"
> echo 100 > $DEBUGFS_MNT/fail_make_request/probability
> # the 1st one fails the first bio which is reading 4k (or more due to
> # readahead), and the 2nd one fails the retry of validation so that it
> # triggers read-repair
> echo 2 > $DEBUGFS_MNT/fail_make_request/times
> echo 0 > $DEBUGFS_MNT/fail_make_request/verbose
> - echo 1 > $SYSFS_BDEV/make-it-fail
> + echo 1 > $sysfs_bdev/make-it-fail
> }
>
> stop_fail()
> {
> + local sysfs_bdev="$1"
> echo 0 > $DEBUGFS_MNT/fail_make_request/probability
> echo 0 > $DEBUGFS_MNT/fail_make_request/times
> - echo 0 > $SYSFS_BDEV/make-it-fail
> + echo 0 > $sysfs_bdev/make-it-fail
> }
>
> _scratch_dev_pool_get 2
> @@ -94,17 +112,21 @@ _scratch_mount -o nospace_cache,nodatasum
> $XFS_IO_PROG -f -d -c "pwrite -S 0xaa -b 128K 0 128K" "$SCRATCH_MNT/foobar" |\
> _filter_xfs_io_offset
>
> -# step 2, corrupt the first 64k of one copy (on SCRATCH_DEV which is the first
> -# one in $SCRATCH_DEV_POOL
> +# step 2, corrupt the first 64k of stripe #1
> echo "step 2......corrupt file extent" >>$seqres.full
>
> ${FILEFRAG_PROG} -v $SCRATCH_MNT/foobar >> $seqres.full
> logical_in_btrfs=`${FILEFRAG_PROG} -v $SCRATCH_MNT/foobar | _filter_filefrag | cut -d '#' -f 1`
> -physical_on_scratch=`get_physical ${logical_in_btrfs}`
> +physical=`get_physical ${logical_in_btrfs} 1`
> +devid=$(get_devid ${logical_in_btrfs} 1)
> +target_dev=$(get_device_path $devid)
>
> +SYSFS_BDEV=`_sysfs_dev $target_dev`
> _scratch_unmount
> -$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 64K $physical_on_scratch 64K" $SCRATCH_DEV |\
> - _filter_xfs_io_offset
> +
> +echo "corrupt stripe 1 devid $devid devpath $target_dev physical $physical" \
> + >> $seqres.full
> +$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 64K $physical 64K" $target_dev > /dev/null
>
> _scratch_mount -o nospace_cache
>
> @@ -118,18 +140,18 @@ while [[ -z ${result} ]]; do
> # invalidate the page cache.
> _scratch_cycle_mount
>
> - start_fail
> + start_fail $SYSFS_BDEV
> result=$(bash -c "
> if [[ \$((\$\$ % 2)) -eq 1 ]]; then
> exec $XFS_IO_PROG -c \"pread 0 4K\" \"$SCRATCH_MNT/foobar\"
> fi");
> - stop_fail
> + stop_fail $SYSFS_BDEV
> done
>
> _scratch_unmount
>
> # check if the repair works
> -$XFS_IO_PROG -c "pread -v -b 512 $physical_on_scratch 512" $SCRATCH_DEV |\
> +$XFS_IO_PROG -c "pread -v -b 512 $physical 512" $target_dev |\
> _filter_xfs_io_offset
>
> _scratch_dev_pool_put
> diff --git a/tests/btrfs/143.out b/tests/btrfs/143.out
> index 66afea4b..a9e82ceb 100644
> --- a/tests/btrfs/143.out
> +++ b/tests/btrfs/143.out
> @@ -1,8 +1,6 @@
> QA output created by 143
> wrote 131072/131072 bytes
> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -wrote 65536/65536 bytes
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa ................
> --
> 2.23.0
>

Other than that (which can probably be fixed at commit time by Eryu)
it looks good and it solves the problem.

Reviewed-by: Filipe Manana <fdmanana@suse.com>

Thanks.

--
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”