FYI, we noticed the following commit (built with gcc-7):

commit: 3ae92b3782182d282a92573abe95c96d34ca6e73 ("btrfs: change the minimum global reserve size")
https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git master

in testcase: xfstests
with following parameters:

	disk: 4HDD
	fs: btrfs
	test: generic-group13

test-description: xfstests is a regression test suite for xfs and other files ystems.
test-url: git://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git


on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 4G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):



If you fix the issue, kindly add following tag
Reported-by: kernel test robot <rong.a.chen@intel.com>

2019-08-31 20:14:07 export TEST_DIR=/fs/vda
2019-08-31 20:14:07 export TEST_DEV=/dev/vda
2019-08-31 20:14:07 export FSTYP=btrfs
2019-08-31 20:14:07 export SCRATCH_MNT=/fs/scratch
2019-08-31 20:14:07 mkdir /fs/scratch -p
2019-08-31 20:14:07 export SCRATCH_DEV_POOL="/dev/vdb /dev/vdc /dev/vdd"
2019-08-31 20:14:07 sed "s:^:generic/:" //lkp/benchmarks/xfstests/tests/generic-group13 | grep -F -f merged_ignored_files
2019-08-31 20:14:07 sed "s:^:generic/:" //lkp/benchmarks/xfstests/tests/generic-group13 | grep -v -F -f merged_ignored_files
2019-08-31 20:14:07 ./check generic/252 generic/253 generic/254 generic/255 generic/256 generic/257 generic/258 generic/260 generic/263 generic/264 generic/265 generic/266 generic/267 generic/268 generic/269 generic/270 generic/271
FSTYP         -- btrfs
PLATFORM      -- Linux/x86_64 vm-snb-4G-3c3aae657790 5.3.0-rc6-00130-g3ae92b3782182 #1 SMP Sat Aug 31 20:03:43 CST 2019
MKFS_OPTIONS  -- /dev/vdb
MOUNT_OPTIONS -- /dev/vdb /fs/scratch

generic/252	 3s
generic/253	 1s
generic/254	 1s
generic/255	 1s
generic/256	 98s
generic/257	 1s
generic/258	 0s
generic/260	[not run] FITRIM not supported on /fs/scratch
generic/263	 33s
generic/264	[not run] xfs_io funshare  failed (old kernel/wrong fs?)
generic/265	 2s
generic/266	 2s
generic/267	 3s
generic/268	 1s
generic/269	_check_btrfs_filesystem: filesystem on /dev/vdb is inconsistent
(see /lkp/benchmarks/xfstests/results//generic/269.full for details)

generic/270	[not run] disk quotas not supported by this filesystem type: btrfs
generic/271	 1s
Ran: generic/252 generic/253 generic/254 generic/255 generic/256 generic/257 generic/258 generic/260 generic/263 generic/264 generic/265 generic/266 generic/267 generic/268 generic/269 generic/270 generic/271
Not run: generic/260 generic/264 generic/270
Failures: generic/269
Failed 1 of 17 tests




To reproduce:

        # build kernel
	cd linux
	cp config-5.3.0-rc6-00130-g3ae92b3782182 .config
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage modules
	make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 INSTALL_MOD_PATH=<mod-install-dir> modules_install
	cd <mod-install-dir>
	find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz


        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email



Thanks,
Rong Chen