From: "Darrick J. Wong" <djwong@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: sandeen@sandeen.net, Chandan Babu R <chandanrlinux@gmail.com>,
linux-xfs@vger.kernel.org, Chaitanya.Kulkarni@wdc.com
Subject: Re: [PATCH 4/6] xfs_scrub: handle concurrent directory updates during name scan
Date: Tue, 9 Feb 2021 08:53:25 -0800 [thread overview]
Message-ID: <20210209165325.GF7190@magnolia> (raw)
In-Reply-To: <20210209093032.GP1718132@infradead.org>
On Tue, Feb 09, 2021 at 09:30:32AM +0000, Christoph Hellwig wrote:
> On Mon, Feb 08, 2021 at 08:11:38PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > The name scanner in xfs_scrub cannot lock a namespace (dirent or xattr)
> > and the kernel does not provide a stable cursor interface, which means
> > that we can see the same byte sequence multiple times during a scan.
> > This isn't a confusing name error since the kernel enforces uniqueness
> > on the byte sequence, so all we need to do here is update the old entry.
>
> So we get the same name but a different ino? I guess that can happen
> with a replacing rename. Maybe state that more clearly?
Ok, the paragraph now reads:
"The name scanner in xfs_scrub cannot lock a namespace (dirent or xattr)
and the kernel does not provide a stable cursor interface, which means
that we can see the same byte sequence multiple times during a scan if
other processes are performing replacing renames on the directory
simultaneously. This isn't a confusing name error since the kernel
enforces uniqueness on the byte sequence, so all we need to do here is
update the old entry."
--D
>
> Otherwise looks good:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2021-02-09 16:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 4:11 [PATCHSET v4 0/6] various: random fixes Darrick J. Wong
2021-02-09 4:11 ` [PATCH 1/6] misc: fix valgrind complaints Darrick J. Wong
2021-02-09 9:19 ` Christoph Hellwig
2021-02-09 4:11 ` [PATCH 2/6] xfs_scrub: detect infinite loops when scanning inodes Darrick J. Wong
2021-02-09 9:26 ` Christoph Hellwig
2021-02-09 4:11 ` [PATCH 3/6] xfs_scrub: load and unload libicu properly Darrick J. Wong
2021-02-09 9:28 ` Christoph Hellwig
2021-02-09 4:11 ` [PATCH 4/6] xfs_scrub: handle concurrent directory updates during name scan Darrick J. Wong
2021-02-09 9:30 ` Christoph Hellwig
2021-02-09 16:53 ` Darrick J. Wong [this message]
2021-02-09 4:11 ` [PATCH 5/6] xfs_repair: check dquot id and type Darrick J. Wong
2021-02-09 9:31 ` Christoph Hellwig
2021-02-09 16:55 ` Darrick J. Wong
2021-02-10 9:48 ` Chandan Babu R
2021-02-11 17:06 ` [PATCH v4.1 " Darrick J. Wong
2021-02-12 12:08 ` Chandan Babu R
2021-02-09 4:11 ` [PATCH 6/6] xfs_scrub: fix weirdness in directory name check code Darrick J. Wong
2021-02-09 9:31 ` Christoph Hellwig
2021-02-10 10:04 ` Chandan Babu R
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