From: Neil Brown <neilb@suse.de>
Date: Tue, 8 May 2012 09:56:38 +0000 (+1000)
Subject: merge: avoid including large Unmatched sections in a conflict.
X-Git-Tag: v0.9~29
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=cff4183fa585a1693293936e7f1035012fc0b4b0;p=wiggle.git

merge: avoid including large Unmatched sections in a conflict.

A large Unmatched section can just distract from the real conflict
and doesn't give useful information.
So if we can close the conflict before a big Unmatched,
do so.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/merge2.c b/merge2.c
index 20b0305..d87b89c 100644
--- a/merge2.c
+++ b/merge2.c
@@ -181,7 +181,7 @@ static int isolate_conflicts(struct file af, struct file bf, struct file cf,
 					 * it wasn't the first one.  'firstk' allows us
 					 * to track which newline we actually use
 					 */
-					int firstk = m[j].al;
+					int firstk = m[j].al+1;
 					if (words) {
 						m[j].hi = m[j].al;
 						break;
@@ -192,7 +192,7 @@ static int isolate_conflicts(struct file af, struct file bf, struct file cf,
 					 */
 					for (k = m[j].al; k > 0; k--)
 						if (ends_line(af.list[m[j].a+k-1])) {
-							if (firstk == m[j].al)
+							if (firstk >= m[j].al)
 								firstk = k;
 							newlines++;
 							if (newlines >= 3) {
@@ -251,10 +251,10 @@ static int isolate_conflicts(struct file af, struct file bf, struct file cf,
 						 * it wasn't the first one.  'firstk' allows us
 						 * to track which newline we actually use
 						 */
-						int firstk = 0;
+						int firstk = -1;
 						for (k = 0 ; k < m[j].al ; k++)
 							if (ends_line(af.list[m[j].a+k])) {
-								if (firstk == 0)
+								if (firstk <= 0)
 									firstk = k;
 								newlines++;
 								if (newlines >= 3) {
@@ -262,6 +262,20 @@ static int isolate_conflicts(struct file af, struct file bf, struct file cf,
 									break;
 								}
 							}
+						if (firstk >= 0 &&
+						    m[j+1].type == Unmatched) {
+							/* If this Unmatched exceeds 3 lines, just stop here */
+							int p;
+							int nl = 0;
+							for (p = 0; p < m[j+1].al ; p++)
+								if (ends_line(af.list[m[j+1].a+p])) {
+									nl++;
+									if (nl > 3)
+										break;
+								}
+							if (nl > 3)
+								k = firstk;
+						}
 						if (k < m[j].al)
 							m[j].lo = k+1;
 						else
diff --git a/tests/linux/md-resync/merge b/tests/linux/md-resync/merge
index 09928a2..fd18d0f 100644
--- a/tests/linux/md-resync/merge
+++ b/tests/linux/md-resync/merge
@@ -1499,6 +1499,19 @@ nomem:
 	raid1_shrink_buffers(conf);
 	return -ENOMEM;
 }
+|||||||
+	if (!sector_nr)
+		if (init_resync(conf))
+			return -ENOMEM;
+	/*
+=======
+	if (sector_nr >= max_sector) {
+		close_sync(conf);
+		return 0;
+	}
+
+	/*
+>>>>>>>
 
 static void end_sync_read(struct buffer_head *bh, int uptodate)
 {
@@ -1528,23 +1541,6 @@ static void end_sync_write(struct buffer_head *bh, int uptodate)
 		raid1_free_buf(r1_bh);
 		sync_request_done(sect, mddev_to_conf(mddev));
 		md_done_sync(mddev,size>>9, uptodate);
-|||||||
-	if (!sector_nr)
-		if (init_resync(conf))
-			return -ENOMEM;
-	/*
-	 * If there is non-resync activity waiting for us then
-	 * put in a delay to throttle resync.
-=======
-	if (sector_nr >= max_sector) {
-		close_sync(conf);
-		return 0;
-	}
-
-	/*
-	 * If there is non-resync activity waiting for us then
-	 * put in a delay to throttle resync.
->>>>>>>
 	}
 }