From: "Darrick J. Wong" <djwong@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
Namjae Jeon <linkinjeon@kernel.org>,
Sungjong Seo <sj1557.seo@samsung.com>,
Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Konstantin Komarov <almaz.alexandrovich@paragon-software.com>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
ntfs3@lists.linux.dev, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 07/13] xfs: document the invalidate_bdev call in invalidate_bdev
Date: Thu, 10 Aug 2023 09:00:35 -0700 [thread overview]
Message-ID: <20230810160035.GD11352@frogsfrogsfrogs> (raw)
In-Reply-To: <20230810155225.GD28000@lst.de>
On Thu, Aug 10, 2023 at 05:52:25PM +0200, Christoph Hellwig wrote:
> On Thu, Aug 10, 2023 at 04:22:15PM +0100, Matthew Wilcox wrote:
> > > blkdev_issue_flush(mp->m_logdev_targp->bt_bdev);
> > > invalidate_bdev(mp->m_logdev_targp->bt_bdev);
> >
> > While I have no complaints with this as a commit message, it's just too
> > verbose for an inline comment, IMO. Something pithier and more generic
> > would seem appropriate. How about:
> >
> > /*
> > * Prevent userspace (eg blkid or xfs_db) from seeing stale data.
> > * XFS is not coherent with the bdev's page cache.
> > */
>
> Well, this completely misses the point. The point is that XFS should
> never have to invalidate the page cache because it's not using it,
> but it has to due to weird races. I tried to condese the message but
> I could not come up with a good one that's not losing information.
Agreed -- it took me a while to set up an arm64 box with just the right
debugging info to figure out why certain fstests were flaky. I do think
it's useful (despite my other reply to willy) to retain the defect
details for hard-to-reproduce errors, and the only way to do that
without encountering the dead url problem is to dump it in a huge
commit message or a comment.
(Too bad there's no way to have a commit whose code comments reference
the commit id of that commit to say "Hey, you need to read this commit
before you touch this line"...)
--D
next prev parent reply other threads:[~2023-08-10 16:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-09 22:05 s_fs_info and ->kill_sb revisited v2 Christoph Hellwig
2023-08-09 22:05 ` [PATCH 01/13] xfs: reformat the xfs_fs_free prototype Christoph Hellwig
2023-08-10 8:53 ` Christian Brauner
2023-08-10 15:51 ` Christoph Hellwig
2023-08-11 7:24 ` Christian Brauner
2023-08-09 22:05 ` [PATCH 02/13] xfs: remove a superfluous s_fs_info NULL check in xfs_fs_put_super Christoph Hellwig
2023-08-09 22:05 ` [PATCH 03/13] xfs: free the xfs_mount in ->kill_sb Christoph Hellwig
2023-08-09 22:05 ` [PATCH 04/13] xfs: remove xfs_blkdev_put Christoph Hellwig
2023-08-09 22:05 ` [PATCH 05/13] xfs: close the RT and log block devices in xfs_free_buftarg Christoph Hellwig
2023-08-09 22:05 ` [PATCH 06/13] xfs: close the external block devices in xfs_mount_free Christoph Hellwig
2023-08-09 22:34 ` Darrick J. Wong
2023-08-09 22:05 ` [PATCH 07/13] xfs: document the invalidate_bdev call in invalidate_bdev Christoph Hellwig
2023-08-09 22:39 ` Darrick J. Wong
2023-08-10 8:20 ` Christian Brauner
2023-08-10 15:53 ` Christoph Hellwig
2023-08-10 15:22 ` Matthew Wilcox
2023-08-10 15:52 ` Christoph Hellwig
2023-08-10 16:00 ` Darrick J. Wong [this message]
2023-08-10 15:57 ` Darrick J. Wong
2023-08-09 22:05 ` [PATCH 08/13] ext4: close the external journal device in ->kill_sb Christoph Hellwig
2023-08-09 22:05 ` [PATCH 09/13] exfat: don't RCU-free the sbi Christoph Hellwig
2023-08-10 13:01 ` Namjae Jeon
2023-08-09 22:05 ` [PATCH 10/13] exfat: free the sbi and iocharset in ->kill_sb Christoph Hellwig
2023-08-10 13:02 ` Namjae Jeon
2023-08-09 22:05 ` [PATCH 11/13] ntfs3: rename put_ntfs ntfs3_free_sbi Christoph Hellwig
2023-08-09 22:05 ` [PATCH 12/13] ntfs3: don't call sync_blockdev in ntfs_put_super Christoph Hellwig
2023-08-09 22:05 ` [PATCH 13/13] ntfs3: free the sbi in ->kill_sb Christoph Hellwig
2023-09-07 13:05 ` Guenter Roeck
2023-09-07 13:54 ` Christian Brauner
2023-09-07 15:23 ` Guenter Roeck
2023-09-07 15:49 ` Christian Brauner
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