Re: [PATCH] common/defrag: Skip defrag tests on DAX-enabled filesystems

[Disha Goel <disgoel@linux.ibm.com>]

On 03/06/26 1:39 am, Darrick J. Wong wrote:
> On Tue, Jun 02, 2026 at 03:44:18PM +0530, Disha Goel wrote:
>> Online defragmentation is not supported on DAX-enabled filesystems
>> because DAX bypasses the page cache required for defrag operations.
>>
>> Add check in _require_defrag() to skip tests when DAX is enabled,
>> avoiding false failures on ext4/301-304, ext4/308 and generic/018.
>>
>> Signed-off-by: Disha Goel <disgoel@linux.ibm.com>
>> ---
>>   common/defrag | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/common/defrag b/common/defrag
>> index 055d0d0e..28db2f7a 100644
>> --- a/common/defrag
>> +++ b/common/defrag
>> @@ -6,6 +6,10 @@
>>   
>>   _require_defrag()
>>   {
>> +    # Defragmentation is not supported on DAX-enabled filesystems
>> +    if echo "$MOUNT_OPTIONS" | grep -qw "dax"; then
>> +        _notrun "Defragmentation not supported on DAX-enabled filesystem"
>> +    fi
> 
> Defrag doesn't work on XFS on DAX as well?  It seems to work fine on my
> VMs...
> 

Thank you for pointing this out. You're right — I missed that xfs defrag
works fine with dax.

I'll fix this in v2 to only skip for ext4.

> <confused>
> 
> --D
> 
>>       case "$FSTYP" in
>>       xfs)
>>           # xfs_fsr does preallocates, require "falloc"
>> -- 
>> 2.45.1
>>
>>

-- 
Regards,
Disha