Commit 47fbf797 authored Aug 08, 2012 by Trond Myklebust

NFSv4.1: Remove a bogus BUG_ON() in nfs4_layoutreturn_done



Ever since commit 0a57cdac (NFSv4.1 send layoutreturn to fence
disconnected data server) we've been sending layoutreturn calls
while there is potentially still outstanding I/O to the data
servers. The reason we do this is to avoid races between replayed
writes to the MDS and the original writes to the DS.

When this happens, the BUG_ON() in nfs4_layoutreturn_done can
be triggered because it assumes that we would never call
layoutreturn without knowing that all I/O to the DS is
finished. The fix is to remove the BUG_ON() now that the
assumptions behind the test are obsolete.

Reported-by: Boaz Harrosh <bharrosh@panasas.com>
Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>=3.5]

parent 7de6e284

fs/nfs/nfs4proc.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -6359,12 +6359,8 @@ static void nfs4_layoutreturn_done(struct rpc_task task, void calldata)
		return;
		}
		spin_lock(&lo->plh_inode->i_lock);
		if (task->tk_status == 0) {
		if (lrp->res.lrs_present) {
		if (task->tk_status == 0 && lrp->res.lrs_present)
		pnfs_set_layout_stateid(lo, &lrp->res.stateid, true);
		} else
		BUG_ON(!list_empty(&lo->plh_segs));
		}
		lo->plh_block_lgets--;
		spin_unlock(&lo->plh_inode->i_lock);
		dprintk("<-- %s\n", __func__);

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