On 2017/09/25 18:53, Amir Goldstein wrote:
On Mon, Sep 25, 2017 at 12:49 PM, Xiao Yang<yangx.jy@xxxxxxxxxxxxxx> wrote:
On 2017/08/27 18:44, Amir Goldstein wrote:
This test is motivated by a bug found in ext4 during random crash
consistency tests.
This test uses device mapper flakey target to demonstrate the bug
found using device mapper log-writes target.
Signed-off-by: Amir Goldstein<amir73il@xxxxxxxxx>
---
Ted,
While working on crash consistency xfstests [1], I stubmled on what
appeared to be an ext4 crash consistency bug.
The tests I used rely on the log-writes dm target code written
by Josef Bacik, which had little exposure to the wide community
as far as I know. I wanted to prove to myself that the found
inconsistency was not due to a test bug, so I bisected the failed
test to the minimal operations that trigger the failure and wrote
a small independent test to reproduce the issue using dm flakey target.
The following fsck error is reliably reproduced by replaying some fsx ops
on overlapping file regions, then emulating a crash, followed by mount,
umount and fsck -nf:
./ltp/fsx -d --replay-ops /tmp/8995.fsxops /mnt/scratch/testfile
1 write 0x137dd thru 0x21445 (0xdc69 bytes)
2 falloc from 0xb531 to 0x16ade (0xb5ad bytes)
3 collapse from 0x1c000 to 0x20000, (0x4000 bytes)
4 write 0x3e5ec thru 0x3ffff (0x1a14 bytes)
5 zero from 0x20fac to 0x27d48, (0x6d9c bytes)
6 mapwrite 0x216ad thru 0x23dfb (0x274f bytes)
All 7 operations completed A-OK!
_check_generic_filesystem: filesystem on /dev/mapper/ssd-scratch is inconsistent
*** fsck.ext4 output ***
fsck from util-linux 2.27.1
e2fsck 1.42.13 (17-May-2015)
Pass 1: Checking inodes, blocks, and sizes
Inode 12, end of extent exceeds allowed value
(logical block 33, physical block 33441, len 7)
Clear? no
Inode 12, i_blocks is 184, should be 128. Fix? no
Hi Amir,
I always get the following output when running your xfstests test case 501.
Now merged as test generic/456
---------------------------------------------------------------------------
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Inode 12, i_size is 147456, should be 163840. Fix? no
---------------------------------------------------------------------------
Could you tell me how to get the expected output as you reported?
I can't say I am doing anything special, but I can say that I get the
same output as you did when running the test inside kvm-xfstests.
Actually, I could not reproduce ANY of the the crash consistency bugs
inside kvm-xfstests. Must be something to do with different timing of
IO with KVM+virtio disks??
When running on my laptop (Ubuntu 16.04 with latest kernel)
on a 10G SSD volume, I always get the error reported above.
I just re-verified with latest stable e2fsprogs (1.43.6).
Hi Amir,
I tested generic/456 with KVM+virtio disks and SATA volumes on some
kernels (including
v3.10.0, the latest kernel), but i still got the same output as i reported.
Could you determine whether the two different outputs are caused by the
same bug
or not ?
Thanks,
Xiao Yang.
Amir.
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