Commit b1a318de authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
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NFSv4: Fix a race in nfs_inode_reclaim_delegation() 



If we race with a delegreturn before taking the spin lock, we
currently end up dropping the delegation stateid.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Tested-by: default avatarOleg Drokin <green@linuxhacker.ru>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 9c27869d

fs/nfs/delegation.c

+5 −7
Original line number Diff line number Diff line
@@ -195,15 +195,13 @@ void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, 
			rcu_read_unlock();

			put_rpccred(oldcred);

			trace_nfs4_reclaim_delegation(inode, res->delegation_type);

		} else {

			return;

		}

		/* We appear to have raced with a delegation return. */

		spin_unlock(&delegation->lock);

			rcu_read_unlock();

			nfs_inode_set_delegation(inode, cred, res);

	}

	} else {

	rcu_read_unlock();

	}

	nfs_inode_set_delegation(inode, cred, res);

}



static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)