On Nov 25, 2013, at 1:13 PM, "Myklebust, Trond" <Trond.Myklebust@xxxxxxxxxx> wrote: > > On Nov 25, 2013, at 12:57, <andros@xxxxxxxxxx> <andros@xxxxxxxxxx> wrote: > >> From: Andy Adamson <andros@xxxxxxxxxx> >> >> The state manager is recovering expired state and recovery OPENs are being >> processed. If kswapd is pruning inodes at the same time, a deadlock can occur >> when kswapd calls evict_inode on an NFSv4.1 inode with a layout, and the >> resultant layoutreturn gets an error that the state mangager is to handle, >> causing the layoutreturn to wait on the (NFS client) cl_rpcwaitq. >> >> At the same time an open is waiting for the inode deletion to complete in >> __wait_on_freeing_inode. >> >> If the open is either the open called by the state manager, or an open from >> the same open owner that is holding the NFSv4.0 sequence id which causes the >> OPEN from the state manager to wait for the sequence id on the Seqid_waitqueue, >> then the state is deadlocked with kswapd. >> >> Do not handle LAYOUTRETURN errors when called from nfs4_evict_inode. > > Why are we waiting for recovery in LAYOUTRETURN at all? Layouts are automatically lost when the server reboots or when the lease is otherwise lost. > > IOW: Is there any reason why we need to special-case nfs4_evict_inode? Shouldn’t we just bail out on error in _all_ cases? Yeah, I was thinking about this as well - perhaps recovering from session-level errors or grace/delay errors would be useful for the block client. -->Andy > > Cheers > Trond > > -- > Trond Myklebust > Linux NFS client maintainer > > NetApp > Trond.Myklebust@xxxxxxxxxx > www.netapp.com > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
