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[PATCH] xfstests: add disk failure simulation test

To: xfs@xxxxxxxxxxx
Subject: [PATCH] xfstests: add disk failure simulation test
From: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
Date: Wed, 13 Feb 2013 19:41:37 +0400
Cc: linux-ext4@xxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx, dchinner@xxxxxxxxxx, Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
Delivered-to: xfs@xxxxxxxxxxx
There are many situations where disk may fail for example
1) brutal usb dongle unplug
2) iscsi (or any other netbdev) failure due to network issues
In this situation filesystem which use this blockdevice is
expected to fail(force RO remount, abort, etc) but whole system
should still be operational. In other words:
1) Kernel should not panic
2) Memory should not leak
3) Data integrity operations (sync,fsync,fdatasync, directio) should fail
   for affected filesystem
4) It should be possible to umount broken filesystem

Later when disk becomes available again we expect(only for journaled 
filesystems):
5) It will be possible to mount filesystem w/o explicit fsck (in order to caught
   issues like https://patchwork.kernel.org/patch/1983981/)
6) Filesystem should be operational
7) After mount/umount has being done all errors should be fixed so fsck should
   not spot any issues.

This test use fault enjection (CONFIG_FAIL_MAKE_REQUEST=y config option )
which force all new IO requests to fail for a given device. Xfs already has
XFS_IOC_GOINGDOWN ioctl which provides similar behaviour, but it is fsspeciffic
and it does it in an easy way because it perform freeze_bdev() before actual
shotdown.

Test run fsstress in background and then force disk failure.
Once disk failed it check that (1)-(4) is true.
Then makes disk available again and check that (5)-(7) is also true

BE CAREFUL!! test known to cause memory corruption for XFS
see: https://gist.github.com/dmonakhov/4945005

Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
---
 292           |  137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 292.out       |    8 +++
 common.config |    1 +
 common.rc     |    6 +++
 group         |    1 +
 5 files changed, 153 insertions(+), 0 deletions(-)
 create mode 100755 292
 create mode 100644 292.out

diff --git a/292 b/292
new file mode 100755
index 0000000..3dd6608
--- /dev/null
+++ b/292
@@ -0,0 +1,136 @@
+#! /bin/bash
+# FSQA Test No. 292
+#
+# Run fsstress and simulate disk failure
+# check filesystem consystency at the end.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2006 Silicon Graphics, Inc.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#
+#-----------------------------------------------------------------------
+#
+# creator
+owner=dmonakhov@xxxxxxxxxx
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1       # failure is the default!
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+# TODO move it to common.blkdev if necessery
+SCRATCH_REAL_DEV=`readlink -f $SCRATCH_DEV`
+SCRATCH_BDEV=`basename $SCRATCH_REAL_DEV`
+
+allow_fail_make_request()
+{
+    [ -f "$DEBUGFS_MNT/fail_make_request/probability" ] \
+       || _notrun "$DEBUGFS_MNT/fail_make_request \
+ not found. Seems that CONFIG_FAIL_MAKE_REQUEST kernel config option not 
enabled"
+
+    echo "Allow global fail_make_request feature"
+    echo 100 > $DEBUGFS_MNT/fail_make_request/probability
+    echo 9999999 > $DEBUGFS_MNT/fail_make_request/times
+    echo 0 >  /sys/kernel/debug/fail_make_request/verbose
+
+}
+
+disallow_fail_make_request()
+{
+    echo "Disallow global fail_make_request feature"
+    echo 0 > $DEBUGFS_MNT/fail_make_request/probability
+    echo 0 > $DEBUGFS_MNT/fail_make_request/times
+}
+
+poweroff_scratch_dev()
+{
+    echo "Force SCRATCH_DEV device failure"
+    echo " echo 1 > /sys/block/$SCRATCH_BDEV/make-it-fail" >> $here/$seq.full
+    echo 1 > /sys/block/$SCRATCH_BDEV/make-it-fail
+
+}
+
+poweron_scratch_dev()
+{
+    echo "Make SCRATCH_DEV device operatable again"
+    echo " echo 0 > /sys/block/$SCRATCH_BDEV/make-it-fail" >> $here/$seq.full
+    echo 0 > /sys/block/$SCRATCH_BDEV/make-it-fail
+
+}
+
+_cleanup()
+{
+    poweron_scratch_dev
+    disallow_fail_make_request
+}
+trap "_cleanup; exit \$status" 1 2 3 15
+
+# Disable all sync operations to get higher load
+FSSTRESS_AVOID="$FSSTRESS_AVOID -ffsync=0 -fsync=0 -ffdatasync=0 -f setattr=1"
+
+_workout()
+{
+       out=$SCRATCH_MNT/fsstress.$$
+       args=`_scale_fsstress_args -p 1 -n999999999 -f setattr=0 
$FSSTRESS_AVOID -d $out`
+       echo ""
+       echo "Run fsstress"
+       echo ""
+       echo "fsstress $args" >> $here/$seq.full
+       $FSSTRESS_PROG $args > /dev/null 2>&1 &
+       pid=$!
+       # Let's it work for awhile
+       sleep $((20 + 10 * $TIME_FACTOR))
+       poweroff_scratch_dev
+       # After device turns in to failed state filesystem may not know about 
that
+       # so buffered write(2) may succeed, but any integrity operation such as
+       # (sync, fsync, fdatasync, direct-io) should fail.
+       dd if=/dev/zero of=$SCRATCH_MNT/touch_failed_filesystem count=1 bs=4k 
conv=fsync \
+           >> $here/$seq.full 2>&1 && \
+           _fail "failed: still able to perform integrity sync on $SCRATCH_MNT"
+
+       kill $pid
+       wait $pid
+
+       # We expect that broken fs is still can be umounted
+       run_check umount -f $SCRATCH_DEV
+       poweron_scratch_dev
+
+       # In order to check that filesystem is able to recover journal on 
mount(2)
+       # perform mount/umount, after that all errors should be fixed
+       run_check _scratch_mount
+       run_check _scratch_unmount
+       _check_scratch_fs
+}
+
+# real QA test starts here
+_supported_fs ext3 ext4 xfs btrfs
+_supported_os Linux
+_need_to_be_root
+_require_scratch
+_require_debugfs
+
+_scratch_mkfs >> $here/$seq.full 2>&1 || _fail "mkfs failed"
+_scratch_mount || _fail "mount failed"
+allow_fail_make_request
+_workout
+status=$?
+disallow_fail_make_request
+exit
diff --git a/292.out b/292.out
new file mode 100644
index 0000000..08d9820
--- /dev/null
+++ b/292.out
@@ -0,0 +1,8 @@
+QA output created by 292
+Allow global fail_make_request feature
+
+Run fsstress
+
+Force SCRATCH_DEV device failure
+Make SCRATCH_DEV device operatable again
+Disallow global fail_make_request feature
diff --git a/common.config b/common.config
index a956a46..f7a2422 100644
--- a/common.config
+++ b/common.config
@@ -75,6 +75,7 @@ export BENCH_PASSES=${BENCH_PASSES:=5}
 export XFS_MKFS_OPTIONS=${XFS_MKFS_OPTIONS:=-bsize=4096}
 export TIME_FACTOR=${TIME_FACTOR:=1}
 export LOAD_FACTOR=${LOAD_FACTOR:=1}
+export DEBUGFS_MNT=${DEBUGFS_MNT:="/sys/kernel/debug"}
 
 export PWD=`pwd`
 #export DEBUG=${DEBUG:=...} # arbitrary CFLAGS really.
diff --git a/common.rc b/common.rc
index 5c3dda1..d5d9c9f 100644
--- a/common.rc
+++ b/common.rc
@@ -1027,6 +1027,12 @@ _require_sparse_files()
     esac
 }
 
+_require_debugfs()
+{
+    #boot_params always present in debugfs
+    [ -d "$DEBUGFS_MNT/boot_params" ] || _notrun "Debugfs not mounted"
+}
+
 # check that a FS on a device is mounted
 # if so, return mount point
 #
diff --git a/group b/group
index b962a33..c409957 100644
--- a/group
+++ b/group
@@ -415,3 +415,4 @@ stress
 289 auto aio dangerous ioctl rw stress
 290 auto aio dangerous ioctl rw stress
 291 auto aio dangerous ioctl rw stress
+292 dangerous rw stress
-- 
1.7.1

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