From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
Chandan Babu R <chandan.babu@oracle.com>,
Christian Brauner <brauner@kernel.org>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 04/10] iomap: zeroing already holds invalidate_lock in iomap_file_buffered_write_punch_delalloc
Date: Wed, 28 Aug 2024 06:51:13 +0200 [thread overview]
Message-ID: <20240828045113.GC31463@lst.de> (raw)
In-Reply-To: <20240827162804.GY865349@frogsfrogsfrogs>
On Tue, Aug 27, 2024 at 09:28:04AM -0700, Darrick J. Wong wrote:
> On Tue, Aug 27, 2024 at 07:09:51AM +0200, Christoph Hellwig wrote:
> > All callers of iomap_zero_range already hold invalidate_lock, so we can't
> > take it again in iomap_file_buffered_write_punch_delalloc.
>
> What about the xfs_zero_range call in xfs_file_write_checks? AFAICT we
> don't hold the invalidate lock there. Did I misread that?
No, I think you're right. My testing just never managed to hit a short
zero while doing the write prep.
I guess I'll need to do something more complicated than the zero flag
then. I initially added a new flag just for that and then (wrongly as you
pointed out) that I don't need it after all.
> Also, would nested takings of the invalidate lock cause a livelock? Or
> is this actually quite broken now?
It is a cold, hard deadlock.
next prev parent reply other threads:[~2024-08-28 4:51 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-27 5:09 fix stale delalloc punching for COW I/O Christoph Hellwig
2024-08-27 5:09 ` [PATCH 01/10] iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release Christoph Hellwig
2024-08-27 16:14 ` Darrick J. Wong
2024-08-28 4:48 ` Christoph Hellwig
2024-08-28 16:13 ` Darrick J. Wong
2024-08-29 3:46 ` Christoph Hellwig
2024-08-29 14:22 ` Darrick J. Wong
2024-08-30 3:42 ` Christoph Hellwig
2024-08-27 5:09 ` [PATCH 02/10] iomap: improve shared block detection in iomap_unshare_iter Christoph Hellwig
2024-08-27 5:44 ` Darrick J. Wong
2024-08-27 5:47 ` Christoph Hellwig
2024-08-27 16:21 ` Darrick J. Wong
2024-08-28 4:49 ` Christoph Hellwig
2024-08-28 16:17 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 03/10] iomap: pass flags to iomap_file_buffered_write_punch_delalloc Christoph Hellwig
2024-08-27 16:22 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 04/10] iomap: zeroing already holds invalidate_lock in iomap_file_buffered_write_punch_delalloc Christoph Hellwig
2024-08-27 16:28 ` Darrick J. Wong
2024-08-28 4:51 ` Christoph Hellwig [this message]
2024-08-27 5:09 ` [PATCH 05/10] iomap: pass the iomap to the punch callback Christoph Hellwig
2024-08-27 16:28 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 06/10] iomap: remove the iomap_file_buffered_write_punch_delalloc return value Christoph Hellwig
2024-08-27 16:36 ` Darrick J. Wong
2024-08-28 4:52 ` Christoph Hellwig
2024-08-28 16:18 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 07/10] xfs: support the COW fork in xfs_bmap_punch_delalloc_range Christoph Hellwig
2024-08-27 16:37 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 08/10] xfs: share a bit more code in xfs_buffered_write_iomap_begin Christoph Hellwig
2024-08-27 16:38 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 09/10] xfs: set IOMAP_F_SHARED for all COW fork allocations Christoph Hellwig
2024-08-27 16:44 ` Darrick J. Wong
2024-08-27 5:09 ` [PATCH 10/10] xfs: punch delalloc extents from the COW fork for COW writes Christoph Hellwig
2024-08-27 16:44 ` Darrick J. Wong
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