Messages in this thread | | | Date | Tue, 5 Jul 2016 14:51:49 +0100 | From | Al Viro <> | Subject | Re: More parallel atomic_open/d_splice_alias fun with NFS and possibly more FSes. |
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On Tue, Jul 05, 2016 at 01:31:10PM +0100, Al Viro wrote: > 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.
See current #for-linus for hopefully fixed variants (both lustre and nfs)
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