Re: [PATCH 0/2] Fix two issues about swapext

[yebin <yebin@huaweicloud.com>]

On 2025/12/15 22:29, Christoph Hellwig wrote:
> On Mon, Dec 15, 2025 at 03:19:43PM +0800, yebin wrote:
>> First, we encountered the issue described in
>> https://access.redhat.com/solutions/6095011 in our production
>
> That's behind a paywall unfortunately.
>
In fact, the root cause of the problem was not identified.
>>> Any chance you could add a reproducer to xfstests?
>>>
>> Yes, this issue is quite reproducible. It occurs inevitably when following
>> certain steps. This problem has existed for a long time. I think the reason
>> it's not easily detected is that the XFS_IOC_SWAPEXT IOCTL command is
>> generally used during defragmentation. Therefore, it is almost never
>> included in typical log replay scenarios.
>
> Can you send out an xfstests for this?  Or at least a shell script
> fragment?
>
You can reproduce issue as follow steps:
mkfs.xfs -f /dev/sdb
mount  /dev/sdb /home/test
fallocate -l1m  /home/test/file1
for i in `seq 1 127`;do fallocate -p -o $((8192*i)) -l 4096 
/home/test/file1;done
fallocate -l1m  /home/test/file2
for i in `seq 1 127`;do fallocate -p -o $((8192*i)) -l 4096 
/home/test/file2;done
umount /home/test
mount /dev/sdb /home/test
xfs_io -c "swapext /home/test/file1" /home/test/file2
truncate -s 81920 /home/test/file1
truncate -s 81920 /home/test/file2
// wait for iclog submit to disk
echo offline > /sys/class/scsi_disk/0\:0\:0\:1/device/state && umount 
/home/test
echo running > /sys/class/scsi_disk/0\:0\:0\:1/device/state
mount /dev/sdb /home/test  //will trigger issue