From: Al Viro <viro@ZenIV.linux.org.uk>
To: Oleg Drokin <green@linuxhacker.ru>
Cc: Mailing List <linux-kernel@vger.kernel.org>,
"<linux-fsdevel@vger.kernel.org>" <linux-fsdevel@vger.kernel.org>
Subject: Re: More parallel atomic_open/d_splice_alias fun with NFS and possibly more FSes.
Date: Tue, 5 Jul 2016 13:31:10 +0100 [thread overview]
Message-ID: <20160705123110.GL14480@ZenIV.linux.org.uk> (raw)
In-Reply-To: <94F1587A-7AFC-4B48-A0FC-F4CE152F18CC@linuxhacker.ru>
On Tue, Jul 05, 2016 at 02:22:48AM -0400, Oleg Drokin wrote:
> > + if (!(open_flags & O_CREAT) && !d_unhashed(dentry)) {
s/d_unhashed/d_in_lookup/ in that.
> So we come racing here from multiple threads (say 3 or more - we have seen this
> in the older crash reports, so totally possible)
>
> > + d_drop(dentry);
>
> One lucky one does this first before the others perform the !d_unhashed check above.
> This makes the other ones to not enter here.
>
> And we are back to the original problem of multiple threads trying to instantiate
> same dentry as before.
Yep. See above - it should've been using d_in_lookup() in the first place,
through the entire nfs_atomic_open(). Same in the Lustre part of fixes,
obviously.
next prev parent reply other threads:[~2016-07-05 12:31 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 4:09 More parallel atomic_open/d_splice_alias fun with NFS and possibly more FSes Oleg Drokin
2016-06-17 4:29 ` Al Viro
2016-06-25 16:38 ` Oleg Drokin
2016-07-03 6:29 ` Al Viro
2016-07-04 0:08 ` Al Viro
2016-07-04 0:37 ` Oleg Drokin
2016-07-04 0:37 ` Oleg Drokin
2016-07-04 3:08 ` Al Viro
2016-07-04 3:55 ` Oleg Drokin
2016-07-04 3:55 ` Oleg Drokin
2016-07-05 2:25 ` Al Viro
2016-07-10 17:01 ` Oleg Drokin
2016-07-10 18:14 ` James Simmons
2016-07-11 1:01 ` Al Viro
2016-07-11 1:03 ` Al Viro
2016-07-11 22:54 ` lustre sendmsg stuff Oleg Drokin
2016-07-11 17:15 ` More parallel atomic_open/d_splice_alias fun with NFS and possibly more FSes James Simmons
2016-07-05 2:28 ` Oleg Drokin
2016-07-05 2:32 ` Oleg Drokin
2016-07-05 4:43 ` Oleg Drokin
2016-07-05 6:22 ` Oleg Drokin
2016-07-05 12:31 ` Al Viro [this message]
2016-07-05 13:51 ` Al Viro
2016-07-05 15:21 ` Oleg Drokin
2016-07-05 17:42 ` Al Viro
2016-07-05 18:12 ` Oleg Drokin
2016-07-05 16:33 ` Oleg Drokin
2016-07-05 18:08 ` Al Viro
2016-07-05 19:12 ` Oleg Drokin
2016-07-05 20:08 ` Al Viro
2016-07-05 20:21 ` Oleg Drokin
2016-07-06 0:29 ` Oleg Drokin
2016-07-06 3:20 ` Al Viro
2016-07-06 3:25 ` Oleg Drokin
2016-07-06 3:25 ` Oleg Drokin
2016-07-06 4:35 ` Oleg Drokin
2016-07-06 4:35 ` Oleg Drokin
2016-07-06 16:24 ` Oleg Drokin
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