Re: [PATCH] btrfs: fix deadlocks with transaction commit when cloning inline extents

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

在 2026/8/30 20:12, Melon Liu 写道:
> On Sat, Aug 29, 2026 at 06:25:11PM +0930, Qu Wenruo wrote:
>>
>>
>> 在 2026/8/29 17:09, Melon Liu 写道:
>>> Commits b48c980b6a7e ("btrfs: fix deadlock between reflink and transaction
>>> commit when using flushoncommit") and 532085d00eb5 ("btrfs: fix deadlock
>>> cloning inline extent when using flushoncommit") moved the destination
>>> i_size update before btrfs_start_transaction() to prevent
>>> extent_writepage() from invalidating a folio beyond EOF.  However, two
>>> deadlock windows remain.
>>>
>>> First, after the folio is dirtied but before i_size is updated,
>>> extent_writepage() can still see the folio beyond EOF.  It calls
>>> folio_invalidate(), and btrfs_invalidate_folio() waits for the destination
>>> extent range lock held by the clone task.
>>>
>>> Second, if extent_writepage() sees the folio within EOF, it proceeds to
>>> writepage_delalloc(), which also waits for the destination extent range
>>> lock.
>>
>> What about letting the agent to create a reproducer, trigger it and paste
>> the lockdep/hang calltrace?
>>
>> Also an ASCII chart showing the window between involved threads?
>>
[...]
>>> Fixes: 05a5a7621ce6 ("Btrfs: implement full reflink support for inline extents")
>>> Cc: stable@vger.kernel.org
>>> Signed-off-by: Melon Liu <melon1335@163.com>
>>
>> And AI disclosure.
>>
> Thanks for the review. I'll address your comments and send a v2.

And also check the sashiko review:

https://sashiko.dev/#/patchset/a74ov5nvs5u4nkqhrs5lp2jaj664wewkqqsjxzhuemzazzmzvx%40eeof6sjb3xdc