Messages in this thread | | | Subject | Re: lockdep: inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-R} usage. | From | Peter Zijlstra <> | Date | Fri, 15 Jan 2010 13:53:15 +0100 |
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On Fri, 2010-01-15 at 23:44 +1100, Dave Chinner wrote: > > > > I can't work out what the <mumble>RECLAIM_FS<mumble> notations are > > > supposed to mean from the code and they are not documented at > > > all, so I need someone to explain what this means before I can > > > determine if it is a valid warning or not.... > > > > The <mumble>RECLAIM_FS<mumble> bit means that lock (iprune_sem) was > > taken from reclaim and is also taken over an allocation. > > So there's an implicit, undocumented requirement that inode reclaim > during unmount requires a filesystem to do GFP_NOFS allocation?
Well, I don't know enough about xfs (of filesystems in generic) to say that with any certainty, but I can imagine inode writeback from the sync that goes with umount to cause issues.
If this inode reclaim is past all that and the filesystem is basically RO, then I don't think so and this could be considered a false positive, in which case we need an annotation for this.
I added hch since he poked at similar reclaim recursions on XFS before and Nick since he thought up this annotation and knows more about filesystems than I do.
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