NFS: Fix for bug in handling of errors for O_DIRECT writes

Commit eda3cef8dd2b83875affe82595db9d0c278879b2 ("NFS: Fix error
handling in nfs_direct_write_result()") ensured that if a WRITE returns
an error, then data->res.verf->committed is not tested (as it is not
initialised).

Then commit 60fa3f769f7651a60125a0f44e3ffe3246d7cf39 ("NFS: Fix two bugs
in the O_DIRECT write code") inadvertently reverted this while fixing
other problems.

So move the test so that we never examine ->committed in an error case,
and fix a speeling error while we are there.

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nfs/direct.c

@@ -549,13 +549,13 @@ static void nfs_direct_write_result(struct rpc_task *task, void *calldata)
 
 	spin_lock(&dreq->lock);
 
-	if (unlikely(dreq->error != 0))
-		goto out_unlock;
 	if (unlikely(status < 0)) {
-		/* An error has occured, so we should not commit */
+		/* An error has occurred, so we should not commit */
 		dreq->flags = 0;
 		dreq->error = status;
 	}
+	if (unlikely(dreq->error != 0))
+		goto out_unlock;
 
 	dreq->count += data->res.count;