diff mbox series

[v13,4/5] btrfs: test verity orphans with dmlogwrites

Message ID 57123fe31da2886cfae01e27ffc43095ef7db7d1.1658277755.git.boris@bur.io (mailing list archive)
State New, archived
Headers show
Series tests for btrfs fsverity | expand

Commit Message

Boris Burkov July 20, 2022, 12:49 a.m. UTC
The behavior of orphans is most interesting across mounts, interrupted
at arbitrary points during fsverity enable. To cover as many such cases
as possible, use dmlogwrites and dmsnapshot as in
log-writes/replay-individual.sh. As we replay the log events, we run a
state machine with different invariants enforced at each state.

There are three possible states for a given point in the log:
0. Verity has not yet started
1. Verity has started but not finished
2. Verity has finished.

The possible transitions with causes are:
0->1: We see an orphan item for the file.
1->2: Running 'fsverity measure' succeeds on the file.

Each state has its own invariant for testing:
0: No verity items exist.
1: Mount should handle the orphan and blow away verity data: expect 0
   Merkle items after mounting.
2: The orphan should be gone and mount should not blow away merkle
   items. Expect the same number of merkle items before and after
   mounting.

As a result, we can be confident that if the file system loses power at
any point during enabling verity on a file, the work is either completed,
or gets rolled-back by mount.

Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 tests/btrfs/291     | 168 ++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/291.out |   2 +
 2 files changed, 170 insertions(+)
 create mode 100755 tests/btrfs/291
 create mode 100644 tests/btrfs/291.out

Comments

Sweet Tea Dorminy July 20, 2022, 2:30 p.m. UTC | #1
On 7/19/22 20:49, Boris Burkov wrote:
> The behavior of orphans is most interesting across mounts, interrupted
> at arbitrary points during fsverity enable. To cover as many such cases
> as possible, use dmlogwrites and dmsnapshot as in
> log-writes/replay-individual.sh. As we replay the log events, we run a
> state machine with different invariants enforced at each state.
> 
> There are three possible states for a given point in the log:
> 0. Verity has not yet started
> 1. Verity has started but not finished
> 2. Verity has finished.
> 
> The possible transitions with causes are:
> 0->1: We see an orphan item for the file.
> 1->2: Running 'fsverity measure' succeeds on the file.
> 
> Each state has its own invariant for testing:
> 0: No verity items exist.
> 1: Mount should handle the orphan and blow away verity data: expect 0
>     Merkle items after mounting.
> 2: The orphan should be gone and mount should not blow away merkle
>     items. Expect the same number of merkle items before and after
>     mounting.
> 
> As a result, we can be confident that if the file system loses power at
> any point during enabling verity on a file, the work is either completed,
> or gets rolled-back by mount.
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
> ---
>   tests/btrfs/291     | 168 ++++++++++++++++++++++++++++++++++++++++++++
>   tests/btrfs/291.out |   2 +
>   2 files changed, 170 insertions(+)
>   create mode 100755 tests/btrfs/291
>   create mode 100644 tests/btrfs/291.out
> 

Still looks good to me, with the fua-hunting rewrite.

It occurred to me last night that the test doesn't verify that it sees a 
disk state in state 1 -- theoretically it could go directly from state 0 
to state 2 -- but I don't see a good way to ensure the test spends time 
in state 1.
diff mbox series

Patch

diff --git a/tests/btrfs/291 b/tests/btrfs/291
new file mode 100755
index 00000000..bbdd183d
--- /dev/null
+++ b/tests/btrfs/291
@@ -0,0 +1,168 @@ 
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 Facebook, Inc. All Rights Reserved.
+#
+# FS QA Test 291
+#
+# Test btrfs consistency after each FUA while enabling verity on a file
+# This test works by following the pattern in log-writes/replay-individual.sh:
+# 1. run a workload (verity + sync) while logging to the log device
+# 2. replay an entry to the replay device
+# 3. snapshot the replay device to the snapshot device
+# 4. run destructive tests on the snapshot device (e.g. mount with orphans)
+# 5. goto 2
+#
+. ./common/preamble
+_begin_fstest auto verity recoveryloop
+
+# Override the default cleanup function.
+_cleanup()
+{
+	cd /
+	_log_writes_cleanup &> /dev/null
+	rm -f $img
+	$LVM_PROG vgremove -f -y $vgname >>$seqres.full 2>&1
+	losetup -d $loop_dev >>$seqres.full 2>&1
+}
+
+# Import common functions.
+. ./common/filter
+. ./common/attr
+. ./common/dmlogwrites
+. ./common/verity
+
+# real QA test starts here
+_supported_fs btrfs
+
+_require_scratch
+_require_test
+_require_loop
+_require_log_writes
+_require_dm_target snapshot
+_require_command $LVM_PROG lvm
+_require_scratch_verity
+_require_btrfs_command inspect-internal dump-tree
+_require_test_program "log-writes/replay-log"
+
+sync_loop() {
+	i=$1
+	[ -z "$i" ] && _fail "sync loop needs a number of iterations"
+	while [ $i -gt 0 ]
+	do
+		$XFS_IO_PROG -c sync $SCRATCH_MNT
+		let i-=1
+	done
+}
+
+dump_tree() {
+	local dev=$1
+	$BTRFS_UTIL_PROG inspect-internal dump-tree $dev
+}
+
+count_item() {
+	local dev=$1
+	local item=$2
+	dump_tree $dev | grep -c "$item"
+}
+
+count_merkle_items() {
+	local dev=$1
+	count_item $dev 'VERITY_\(DESC\|MERKLE\)_ITEM'
+}
+
+_log_writes_init $SCRATCH_DEV
+_log_writes_mkfs
+_log_writes_mount
+
+f=$SCRATCH_MNT/fsv
+MB=$((1024 * 1024))
+img=$TEST_DIR/$$.img
+$XFS_IO_PROG -fc "pwrite -q 0 $((10 * $MB))" $f
+$XFS_IO_PROG -c sync $SCRATCH_MNT
+sync_loop 10 &
+sync_proc=$!
+_fsv_enable $f
+$XFS_IO_PROG -c sync $SCRATCH_MNT
+wait $sync_proc
+
+_log_writes_unmount
+_log_writes_remove
+
+# the snapshot and the replay will each be the size of the log writes dev
+# so we create a loop device of size 2 * logwrites and then split it into
+# replay and snapshot with lvm.
+log_writes_blocks=$(blockdev --getsz $LOGWRITES_DEV)
+replay_bytes=$((512 * $log_writes_blocks))
+img_bytes=$((2 * $replay_bytes))
+
+$XFS_IO_PROG -fc "pwrite -q -S 0 $img_bytes $MB" $img >>$seqres.full 2>&1 || \
+	_fail "failed to create image for loop device"
+loop_dev=$(losetup -f --show $img)
+vgname=vg_replay
+lvname=lv_replay
+replay_dev=/dev/mapper/vg_replay-lv_replay
+snapname=lv_snap
+snap_dev=/dev/mapper/vg_replay-$snapname
+
+$LVM_PROG vgcreate -f $vgname $loop_dev >>$seqres.full 2>&1 || _fail "failed to vgcreate $vgname"
+$LVM_PROG lvcreate -L "$replay_bytes"B -n $lvname $vgname -y >>$seqres.full 2>&1 || \
+	_fail "failed to lvcreate $lvname"
+$UDEV_SETTLE_PROG >>$seqres.full 2>&1
+
+replay_log_prog=$here/src/log-writes/replay-log
+num_entries=$($replay_log_prog --log $LOGWRITES_DEV --num-entries)
+entry=$($replay_log_prog --log $LOGWRITES_DEV --replay $replay_dev --find --end-mark mkfs | cut -d@ -f1)
+prev=$(_log_writes_mark_to_entry_number mkfs)
+[ -z "$prev" ] && _fail "failed to locate entry mark 'mkfs'"
+cur=$(_log_writes_find_next_fua $prev)
+
+# state = 0: verity hasn't started
+# state = 1: verity underway
+# state = 2: verity done
+state=0
+while [ ! -z "$cur" ];
+do
+	_log_writes_replay_log_range $cur $replay_dev >> $seqres.full
+
+	$LVM_PROG lvcreate -s -L 4M -n $snapname $vgname/$lvname >>$seqres.full 2>&1 || \
+		_fail "Failed to create snapshot"
+	$UDEV_SETTLE_PROG >>$seqres.full 2>&1
+
+	orphan=$(count_item $snap_dev ORPHAN)
+	[ $state -eq 0 ] && [ $orphan -gt 0 ] && state=1
+
+	pre_mount=$(count_merkle_items $snap_dev)
+	_mount $snap_dev $SCRATCH_MNT || _fail "mount failed at entry $cur"
+	fsverity measure $SCRATCH_MNT/fsv >>$seqres.full 2>&1
+	measured=$?
+	umount $SCRATCH_MNT
+	[ $state -eq 1 ] && [ $measured -eq 0 ] && state=2
+	[ $state -eq 2 ] && ([ $measured -eq 0 ] || _fail "verity done, but measurement failed at entry $cur")
+	post_mount=$(count_merkle_items $snap_dev)
+
+	echo "entry: $cur, state: $state, orphan: $orphan, pre_mount: $pre_mount, post_mount: $post_mount" >> $seqres.full
+
+	if [ $state -eq 1 ]; then
+		[ $post_mount -eq 0 ] || \
+			_fail "mount failed to clear under-construction merkle items pre: $pre_mount, post: $post_mount at entry $cur";
+	fi
+	if [ $state -eq 2 ]; then
+		[ $pre_mount -gt 0 ] || \
+			_fail "expected to have verity items before mount at entry $cur"
+		[ $pre_mount -eq $post_mount ] || \
+			_fail "mount cleared merkle items after verity was enabled $pre_mount vs $post_mount at entry $cur";
+	fi
+
+	$LVM_PROG lvremove $vgname/$snapname -y >>$seqres.full
+
+	prev=$cur
+	cur=$(_log_writes_find_next_fua $(($cur + 1)))
+done
+
+[ $state -eq 2 ] || _fail "expected to reach verity done state"
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
diff --git a/tests/btrfs/291.out b/tests/btrfs/291.out
new file mode 100644
index 00000000..04605c70
--- /dev/null
+++ b/tests/btrfs/291.out
@@ -0,0 +1,2 @@ 
+QA output created by 291
+Silence is golden