Hi,
On Tue, Aug 25, 2020 at 11:20 AM Christoph Hellwig <[email protected]> wrote:
>
> On Tue, Aug 25, 2020 at 10:26:14AM +0100, Yuxuan Shui wrote:
> > Hi,
> >
> > Do we actually want to fix this bug or not? There are a number of
> > people actually seeing this bug.
>
> bmap should not succeed for unwritten extents.
Why not? Unwritten extents are still allocated extents.
>
> > If you think this is not the right fix, what do you think we should
> > do? If the correct fix is to make ext4 use iomap_swapfile_activate,
> > maybe we should CC the ext4 people too?
>
> Yes, ext4 should use iomap_swapfile_activate.
OK, let me CC the ext4 people.
Context:
https://bugzilla.kernel.org/show_bug.cgi?id=207585
> commit ac58e4fb03f9d111d733a4ad379d06eef3a24705 moved ext4_bmap from
> generic_block_bmap to iomap_bmap, this introduced a regression which
> prevents some user from using previously working swapfiles. The kernel
> will complain about holes while there are none.
> What is happening here is that the swapfile has unwritten mappings,
> which is rejected by iomap_bmap, but was accepted by ext4_get_block.
--
Regards
Yuxuan Shui
On Tue, Aug 25, 2020 at 11:40:34AM +0100, Yuxuan Shui wrote:
> Hi,
>
> On Tue, Aug 25, 2020 at 11:20 AM Christoph Hellwig <[email protected]> wrote:
> >
> > On Tue, Aug 25, 2020 at 10:26:14AM +0100, Yuxuan Shui wrote:
> > > Hi,
> > >
> > > Do we actually want to fix this bug or not? There are a number of
> > > people actually seeing this bug.
> >
> > bmap should not succeed for unwritten extents.
>
> Why not? Unwritten extents are still allocated extents.
Because you can't read from or write to them.
On 8/25/20 4:10 PM, Yuxuan Shui wrote:
> Hi,
>
> On Tue, Aug 25, 2020 at 11:20 AM Christoph Hellwig <[email protected]> wrote:
>>
>> On Tue, Aug 25, 2020 at 10:26:14AM +0100, Yuxuan Shui wrote:
>>> Hi,
>>>
>>> Do we actually want to fix this bug or not? There are a number of
>>> people actually seeing this bug.
>>
>> bmap should not succeed for unwritten extents.
>
> Why not? Unwritten extents are still allocated extents.
>
>>
>>> If you think this is not the right fix, what do you think we should
>>> do? If the correct fix is to make ext4 use iomap_swapfile_activate,
>>> maybe we should CC the ext4 people too?
>>
>> Yes, ext4 should use iomap_swapfile_activate.
>
> OK, let me CC the ext4 people.
>
> Context:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=207585
Thanks for adding ext4 list. Noticed this report for the first time now.
Maybe I missed it from fsdevel. Let me have a look at it.
-ritesh