md/raid5: move resolving of reconstruct_state earlier in

stripe_handle.

The chunk of code in stripe_handle which responds to a
*_result value in reconstruct_state is really the completion
of some processing that happened outside of handle_stripe
(possibly asynchronously) and so should be one of the first
things done in handle_stripe().

After the next patch it will be important that it happens before
handle_stripe_clean_event(), as that will clear some dev->flags
bit that this code tests.
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/raid5.c

@@ -3490,40 +3490,6 @@ static void handle_stripe(struct stripe_head *sh)
 			handle_failed_sync(conf, sh, &s);
 	}
 
-	/*
-	 * might be able to return some write requests if the parity blocks
-	 * are safe, or on a failed drive
-	 */
-	pdev = &sh->dev[sh->pd_idx];
-	s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
-		|| (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
-	qdev = &sh->dev[sh->qd_idx];
-	s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
-		|| (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
-		|| conf->level < 6;
-
-	if (s.written &&
-	    (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
-			     && !test_bit(R5_LOCKED, &pdev->flags)
-			     && (test_bit(R5_UPTODATE, &pdev->flags) ||
-				 test_bit(R5_Discard, &pdev->flags))))) &&
-	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
-			     && !test_bit(R5_LOCKED, &qdev->flags)
-			     && (test_bit(R5_UPTODATE, &qdev->flags) ||
-				 test_bit(R5_Discard, &qdev->flags))))))
-		handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
-
-	/* Now we might consider reading some blocks, either to check/generate
-	 * parity, or to satisfy requests
-	 * or to load a block that is being partially written.
-	 */
-	if (s.to_read || s.non_overwrite
-	    || (conf->level == 6 && s.to_write && s.failed)
-	    || (s.syncing && (s.uptodate + s.compute < disks))
-	    || s.replacing
-	    || s.expanding)
-		handle_stripe_fill(sh, &s, disks);
-
 	/* Now we check to see if any write operations have recently
 	 * completed
 	 */
@@ -3561,6 +3527,40 @@ static void handle_stripe(struct stripe_head *sh)
 			s.dec_preread_active = 1;
 	}
 
+	/*
+	 * might be able to return some write requests if the parity blocks
+	 * are safe, or on a failed drive
+	 */
+	pdev = &sh->dev[sh->pd_idx];
+	s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
+		|| (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
+	qdev = &sh->dev[sh->qd_idx];
+	s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
+		|| (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
+		|| conf->level < 6;
+
+	if (s.written &&
+	    (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
+			     && !test_bit(R5_LOCKED, &pdev->flags)
+			     && (test_bit(R5_UPTODATE, &pdev->flags) ||
+				 test_bit(R5_Discard, &pdev->flags))))) &&
+	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
+			     && !test_bit(R5_LOCKED, &qdev->flags)
+			     && (test_bit(R5_UPTODATE, &qdev->flags) ||
+				 test_bit(R5_Discard, &qdev->flags))))))
+		handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
+
+	/* Now we might consider reading some blocks, either to check/generate
+	 * parity, or to satisfy requests
+	 * or to load a block that is being partially written.
+	 */
+	if (s.to_read || s.non_overwrite
+	    || (conf->level == 6 && s.to_write && s.failed)
+	    || (s.syncing && (s.uptodate + s.compute < disks))
+	    || s.replacing
+	    || s.expanding)
+		handle_stripe_fill(sh, &s, disks);
+
 	/* Now to consider new write requests and what else, if anything
 	 * should be read.  We do not handle new writes when:
 	 * 1/ A 'write' operation (copy+xor) is already in flight.