From: Al Viro <viro@zeniv.linux.org.uk>
To: Ian Kent <raven@themaw.net>
Cc: "Darrick J. Wong" <djwong@kernel.org>,
Jinliang Zheng <alexjlzheng@gmail.com>,
alexjlzheng@tencent.com, bfoster@redhat.com, david@fromorbit.com,
linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
rcu@vger.kernel.org
Subject: Re: About the conflict between XFS inode recycle and VFS rcu-walk
Date: Mon, 27 May 2024 01:18:23 +0100 [thread overview]
Message-ID: <20240527001823.GC2118490@ZenIV> (raw)
In-Reply-To: <d2d010ce-51eb-4e99-b717-162e88f8d3fc@themaw.net>
On Mon, May 27, 2024 at 07:51:39AM +0800, Ian Kent wrote:
> Indeed, that's what I found when I had a quick look.
>
>
> Maybe a dentry (since that's part of the subject of the path walk and inode
> is readily
>
> accessible) flag could be used since there's opportunity to set it in vfs
> callbacks that
>
> are done as a matter of course.
You might recheck ->d_seq after fetching ->get_link there; with XFS
->get_link() unconditionlly failing in RCU mode that would prevent
this particular problem. But it would obviously have to be done
in pick_link() itself (and I refuse to touch that area in 5.4 -
carrying those changes across the e.g. 5.6 changes in pathwalk
machinery is too much).
And it's really just the tip of the iceberg - e.g. I'd expect a massive
headache in ACL-related part of permission checks, etc.
next prev parent reply other threads:[~2024-05-27 0:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 11:38 About the conflict between XFS inode recycle and VFS rcu-walk alexjlzheng
2023-12-08 0:14 ` Dave Chinner
2024-01-31 6:35 ` Jinliang Zheng
2024-01-31 19:30 ` Darrick J. Wong
2024-05-15 15:54 ` alexjlzheng
2024-05-16 4:56 ` Jinliang Zheng
2024-05-16 7:08 ` Ian Kent
2024-05-16 7:23 ` Ian Kent
2024-05-20 17:36 ` Darrick J. Wong
2024-05-21 1:35 ` Ian Kent
2024-05-21 2:13 ` Ian Kent
2024-05-26 15:04 ` Jinliang Zheng
2024-05-26 17:21 ` Paul E. McKenney
2024-05-26 23:51 ` Ian Kent
2024-05-27 0:18 ` Al Viro [this message]
2024-05-28 15:51 ` Brian Foster
2024-05-27 9:41 ` Dave Chinner
2024-05-27 13:56 ` Jinliang Zheng
2024-05-28 2:10 ` Dave Chinner
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