From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org, Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH] xfs: recheck appropriateness of map_shared lock
Date: Thu, 19 Jan 2023 10:31:06 -0800 [thread overview]
Message-ID: <Y8mMailEevUSZkG+@infradead.org> (raw)
In-Reply-To: <Y8ib6ls32e/pJezE@magnolia>
On Wed, Jan 18, 2023 at 05:24:58PM -0800, Darrick J. Wong wrote:
> xfs_ilock(ip, lock_mode);
> +
> + /*
> + * It's possible that the unlocked access of the data fork to determine
> + * the lock mode could have raced with another thread that was failing
> + * to load the bmbt but hadn't yet torn down the iext tree. Recheck
> + * the lock mode and upgrade to an exclusive lock if we need to.
> + */
> + if (lock_mode == XFS_ILOCK_SHARED &&
> + xfs_need_iread_extents(&ip->i_df)) {
Eww. I think the proper fix here is to make sure
xfs_need_iread_extents does not return false until we're actually
read the extents. So I think we'll need a new inode flag
XFS_INEED_READ - gets set when reading inode in btree format,
and gets cleared at the very end of xfs_iread_extents once we know
the read succeeded.
next prev parent reply other threads:[~2023-01-19 18:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-19 1:24 [PATCH] xfs: recheck appropriateness of map_shared lock Darrick J. Wong
2023-01-19 5:14 ` Dave Chinner
2023-01-19 18:39 ` Christoph Hellwig
2023-01-19 20:34 ` Dave Chinner
2023-02-28 20:08 ` Darrick J. Wong
2023-01-19 18:31 ` Christoph Hellwig [this message]
2023-04-11 1:05 ` Darrick J. Wong
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