From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from userp2130.oracle.com ([156.151.31.86]:47758 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726427AbeJIBmS (ORCPT ); Mon, 8 Oct 2018 21:42:18 -0400 Subject: Re: [PATCH] fstests: btrfs verify hardening agaist duplicate fsid References: <1538383475-2532-1-git-send-email-anand.jain@oracle.com> <20181006101449.GJ17817@desktop> From: Anand Jain Message-ID: Date: Tue, 9 Oct 2018 02:28:54 +0800 MIME-Version: 1.0 In-Reply-To: <20181006101449.GJ17817@desktop> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: fstests-owner@vger.kernel.org To: Eryu Guan Cc: fstests@vger.kernel.org, linux-btrfs@vger.kernel.org List-ID: On 10/06/2018 06:14 PM, Eryu Guan wrote: > On Mon, Oct 01, 2018 at 04:44:35PM +0800, Anand Jain wrote: >> We have a known bug in btrfs, that we let the device path be changed >> after the device has been mounted. So using this loop hole the new >> copied device would appears as if its mounted immediately after its >> been copied. So this test case reproduces this issue. >> >> For example: >> >> Initially.. /dev/mmcblk0p4 is mounted as / >> >> lsblk >> NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT >> mmcblk0 179:0 0 29.2G 0 disk >> |-mmcblk0p4 179:4 0 4G 0 part / >> |-mmcblk0p2 179:2 0 500M 0 part /boot >> |-mmcblk0p3 179:3 0 256M 0 part [SWAP] >> `-mmcblk0p1 179:1 0 256M 0 part /boot/efi >> >> btrfs fi show >> Label: none uuid: 07892354-ddaa-4443-90ea-f76a06accaba >> Total devices 1 FS bytes used 1.40GiB >> devid 1 size 4.00GiB used 3.00GiB path /dev/mmcblk0p4 >> >> Copy mmcblk0 to sda >> dd if=/dev/mmcblk0 of=/dev/sda >> >> And immediately after the copy completes the change in the device >> superblock is notified which the automount scans using >> btrfs device scan and the new device sda becomes the mounted root >> device. >> >> lsblk >> NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT >> sda 8:0 1 14.9G 0 disk >> |-sda4 8:4 1 4G 0 part / >> |-sda2 8:2 1 500M 0 part >> |-sda3 8:3 1 256M 0 part >> `-sda1 8:1 1 256M 0 part >> mmcblk0 179:0 0 29.2G 0 disk >> |-mmcblk0p4 179:4 0 4G 0 part >> |-mmcblk0p2 179:2 0 500M 0 part /boot >> |-mmcblk0p3 179:3 0 256M 0 part [SWAP] >> `-mmcblk0p1 179:1 0 256M 0 part /boot/efi >> btrfs fi show / >> Label: none uuid: 07892354-ddaa-4443-90ea-f76a06accaba >> Total devices 1 FS bytes used 1.40GiB >> devid 1 size 4.00GiB used 3.00GiB path /dev/sda4 >> >> The bug is quite nasty that you can't either unmount /dev/sda4 or >> /dev/mmcblk0p4. And the problem does not get solved until you take >> the sda out of the system on to another system to change its fsid using >> the 'btrfstune -u' command. >> >> Signed-off-by: Anand Jain > > Looks like that the test will break the whole test env as it leaves an > unmountable $SCRATCH_MNT. I'd wait for the fix to get in first before > merging the test, in case it breaks normal regression tests. (I noticed > that the test is not in 'auto' group, so it's not that dangerous.) Its possible that its unmountable without the kernel patch. But I am unable to reproduce it consistently with or without the kernel patch. Any idea ways to make it auto for kernels without the patch? > Also, it'd be great if test can be reviewed by btrfs folks too! > >> --- >> tests/btrfs/173 | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++ >> tests/btrfs/173.out | 5 ++++ >> tests/btrfs/group | 1 + >> 3 files changed, 78 insertions(+) >> create mode 100755 tests/btrfs/173 >> create mode 100644 tests/btrfs/173.out >> >> diff --git a/tests/btrfs/173 b/tests/btrfs/173 >> new file mode 100755 >> index 000000000000..f59a62e206c3 >> --- /dev/null >> +++ b/tests/btrfs/173 >> @@ -0,0 +1,72 @@ >> +#! /bin/bash >> +# SPDX-License-Identifier: GPL-2.0 >> +# Copyright (c) 2018 Oracle. All Rights Reserved. >> +# >> +# FS QA Test 173 >> +# >> +# Fuzzy test for FS image duplication. >> +# Could be fixed by >> +# [patch] btrfs: harden agaist duplicate fsid >> +# >> +seq=`basename $0` >> +seqres=$RESULT_DIR/$seq >> +echo "QA output created by $seq" >> + >> +here=`pwd` >> +tmp=/tmp/$$ >> +status=1 # failure is the default! >> +trap "_cleanup; exit \$status" 0 1 2 3 15 >> + >> +_cleanup() >> +{ >> + cd / >> + rm -f $tmp.* >> +} >> + >> +# get standard environment, filters and checks >> +. ./common/rc >> +. ./common/filter >> + >> +# remove previous $seqres.full before test >> +rm -f $seqres.full >> + >> +# real QA test starts here >> + >> +# Modify as appropriate. >> +_supported_fs btrfs >> +_supported_os Linux >> +_require_scratch_dev_pool 2 >> +_scratch_dev_pool_get 2 >> + >> +dev_foo=$(echo $SCRATCH_DEV_POOL | awk '{print $1}' | rev | cut -d"/" -f1 | rev) >> +dev_bar=$(echo $SCRATCH_DEV_POOL | awk '{print $2}' | rev | cut -d"/" -f1 | rev) > > This doesn't work if the devices in SCRATCH_DEV_POOL are symlinks, e.g. > lvm devices: /dev/mapper/testvg-testlv1, dev_foo is "testvg-testlv1" in > this case. Ah, right will fix. >> + >> +_mkfs_dev /dev/$dev_foo > > But /dev/testvg-testlv1 isn't existed. > > _short_dev and/or _real_dev is useful in this case. e.g. > > dev_foo=$(echo $SCRATCH_DEV_POOL | awk '{print $1}') > # dev_foo is like "dm-1" > dev_foo=$(_short_dev $dev_foo) > # dev_foo is like "/dev/dm-1" > dev_foo=$(_real_dev $dev_foo) I changed the code a bit which avoids the split. Pls review if that will be ok. >> +_mount /dev/$dev_foo $SCRATCH_MNT > > It'd better to mount non-SCRATCH_DEV to other mount point, e.g. > $TEST_DIR/$seq.mnt Will do, any idea why? Isn't the framework automatically try to unmount SCRATCH_MNT. Thanks, Anand > Thanks, > Eryu > >> + >> +echo mount before btrfs image clone | tee -a $seqres.full >> +findmnt /dev/$dev_foo | grep -v TARGET | awk '{print $1" "$2}' | \ >> + sed -e "s/$dev_foo/dev_foo/g" | _filter_scratch | tee -a $seqres.full >> +findmnt /dev/$dev_bar | grep -v TARGET | awk '{print $1" "$2}' | \ >> + sed -e "s/$dev_bar/dev_bar/g" | _filter_scratch | tee -a $seqres.full >> + >> +for sb_bytenr in 65536 67108864 >> +do >> + echo -n "dd status=none if=/dev/$dev_foo of=/dev/$dev_bar bs=1 "\ >> + "seek=$sb_bytenr skip=$sb_bytenr count=4096" >> $seqres.full >> + dd status=none if=/dev/$dev_foo of=/dev/$dev_bar bs=1 seek=$sb_bytenr \ >> + skip=$sb_bytenr count=4096 >> $seqres.full 2>&1 >> + echo ..:$? >> $seqres.full >> +done >> + >> +echo mount after btrfs image clone | tee -a $seqres.full >> +findmnt /dev/$dev_foo | grep -v TARGET | awk '{print $1" "$2}' | \ >> + sed -e "s/$dev_foo/dev_foo/g" | _filter_scratch | tee -a $seqres.full >> +findmnt /dev/$dev_bar | grep -v TARGET | awk '{print $1" "$2}' | \ >> + sed -e "s/$dev_bar/dev_bar/g" | _filter_scratch | tee -a $seqres.full >> + >> +_scratch_dev_pool_put >> + >> +# success, all done >> +status=0 >> +exit >> diff --git a/tests/btrfs/173.out b/tests/btrfs/173.out >> new file mode 100644 >> index 000000000000..a2ef7a26f4b9 >> --- /dev/null >> +++ b/tests/btrfs/173.out >> @@ -0,0 +1,5 @@ >> +QA output created by 173 >> +mount before btrfs image clone >> +SCRATCH_MNT /dev/dev_foo >> +mount after btrfs image clone >> +SCRATCH_MNT /dev/dev_foo >> diff --git a/tests/btrfs/group b/tests/btrfs/group >> index 45782565c3b7..b2f1393f3e97 100644 >> --- a/tests/btrfs/group >> +++ b/tests/btrfs/group >> @@ -175,3 +175,4 @@ >> 170 auto quick snapshot >> 171 auto quick qgroup >> 172 auto quick punch >> +173 volume >> -- >> 1.8.3.1 >>