Re: fix a few zoned append issues v2 (now with Ccs)

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

在 2024/12/4 10:47, Christoph Hellwig 写道:
> On Tue, Dec 03, 2024 at 06:01:20PM +0100, David Sterba wrote:
>> On Fri, Nov 08, 2024 at 03:48:57PM +0100, Christoph Hellwig wrote:
>>> On Mon, Nov 04, 2024 at 07:26:28AM +0100, Christoph Hellwig wrote:
>>>> Hi Jens, hi Damien, hi btrfs maintainers,
>>>
>>> How should we proceed with this?  Should Jens just pick up the block
>>> bits and the btrfs maintainers pick up the btrfs once they are
>>> ready and the block bits made it upstream?
>>
>> The block layer patches are now in master, I'm adding the remaining
>> patches to btrfs for-next.
>
> Thanks.  I wanted to resend them, but my baseline testing still showed
> crashes in generic/475 so I was looking into an expunge config to
> check if there are no regressions first (there really shouldn't, but
> I wanted to double check).
>

Talking about generic/475 crash, it looks like there is something wrong
inside btrfs' space reservation code, which causes run_delalloc_range()
to fail with ENOSPC (which should not happen).

If my memory works correctly, at least 3 release ago we didn't hit such
ENOSPC during run_delalloc_range().


I'm working on fixing the involved error handling, there are some
patches to reduce involved crashes:

For ordered extent double freeing:
https://lore.kernel.org/linux-btrfs/cover.1732695237.git.wqu@suse.com/

For ENOSPC error handling in run_delalloc_range():
https://lore.kernel.org/linux-btrfs/0b4675971b718709497ca35c0d69e06db0c69d58.1732867087.git.wqu@suse.com/
https://lore.kernel.org/linux-btrfs/3e5d5665ef36ee43e310be321073210785b89adc.1733273653.git.wqu@suse.com/

Which can help you to continue, but at least on my aarch64 VMs with 64K
page size and 4K block size, I can still hit random failures related to
unfinished iput or run-away locked pages.


Unfortunately I'm not educated enough to pin down the
run_delalloc_range() ENOSPC errors, but only use this chance to fix the
error handling...

Thanks,
Qu