On 07/28/2016 09:22 AM, Shaohua Li wrote:
On Wed, Jul 27, 2016 at 08:07:19AM -0400, Yi Zhang wrote:
Hello maintainer
Here is another strange phenomenon I found after do -f, -r, --add-journal for write-journal device.
Kernel version: 4.7.0-rc7
Steps I used:
mdadm --create --run /dev/md0 --level 4 --metadata 1.2 --raid-devices 7 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 /dev/loop5 /dev/loop6 /dev/loop7 --write-journal /dev/loop0 --bitmap=internal --bitmap-chunk=64M --chunk 512
mdadm --wait /dev/md0
mkfs.ext4 /dev/md0
mount -t ext4 /dev/md0 /mnt/fortest
cp bigfile /mnt/fortest &
wait
md5sum /mnt/fortest/bigfile > md5sum3
mdadm /dev/md0 -f /dev/loop0
since loop0 is the journal device and it fails, we will mark the md0 readonly
at this point. Filesystem can't do any write. It's possible the fortest/md5sum3
files not hit disk yet, and are lost. I think your test should do a sync before
mark journal disk failure.
I add sync operation before mark journal disk failure, this issue cannot
be reproduced any more,
thanks
Yi
mdadm /dev/md0 -r /dev/loop0
umount /dev/md0 -l
mdadm -o /dev/md0
mdadm /dev/md0 --add-journal /dev/loop0
mdadm --wait /dev/md0
mdadm -D /dev/md0
mount /dev/md0 /mnt/fortest
md5sum /mnt/fortest/bigfile > md5sum2 #<----this test file disappeared
If a sync is done before journal disk fails and you still see the file
disappeared, it's a bug.
Thanks,
Shaohua
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