[PATCH] md/raid1: clear bitmap when fullsync completes

We need to be careful differentiating between a resync of a complete array,
in which we can clear the bitmap, and a resync of a degraded array, in
which we cannot.

This patch cleans all that up.

Cc: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/md/bitmap.c

@@ -1345,7 +1345,8 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
 	}
 }
 
-int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks)
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
+			int degraded)
 {
 	bitmap_counter_t *bmc;
 	int rv;
@@ -1362,8 +1363,10 @@ int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks)
 			rv = 1;
 		else if (NEEDED(*bmc)) {
 			rv = 1;
-			*bmc |= RESYNC_MASK;
-			*bmc &= ~NEEDED_MASK;
+			if (!degraded) { /* don't set/clear bits if degraded */
+				*bmc |= RESYNC_MASK;
+				*bmc &= ~NEEDED_MASK;
+			}
 		}
 	}
 	spin_unlock_irq(&bitmap->lock);

drivers/md/raid1.c

@@ -1126,21 +1126,19 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 		 * only be one in raid1 resync.
 		 * We can find the current addess in mddev->curr_resync
 		 */
-		if (!conf->fullsync) {
-			if (mddev->curr_resync < max_sector)
-				bitmap_end_sync(mddev->bitmap,
-						mddev->curr_resync,
+		if (mddev->curr_resync < max_sector) /* aborted */
+			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
 						&sync_blocks, 1);
-			bitmap_close_sync(mddev->bitmap);
-		}
-		if (mddev->curr_resync >= max_sector)
+		else /* completed sync */
 			conf->fullsync = 0;
+
+		bitmap_close_sync(mddev->bitmap);
 		close_sync(conf);
 		return 0;
 	}
 
-	if (!conf->fullsync &&
-	    !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks)) {
+	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, mddev->degraded) &&
+	    !conf->fullsync) {
 		/* We can skip this block, and probably several more */
 		*skipped = 1;
 		return sync_blocks;
@@ -1243,15 +1241,15 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 			len = (max_sector - sector_nr) << 9;
 		if (len == 0)
 			break;
-		if (!conf->fullsync) {
-			if (sync_blocks == 0) {
-				if (!bitmap_start_sync(mddev->bitmap,
-						       sector_nr, &sync_blocks))
-					break;
-				if (sync_blocks < (PAGE_SIZE>>9))
-					BUG();
-				if (len > (sync_blocks<<9)) len = sync_blocks<<9;
-			}
+		if (sync_blocks == 0) {
+			if (!bitmap_start_sync(mddev->bitmap, sector_nr,
+					&sync_blocks, mddev->degraded) &&
+					!conf->fullsync)
+				break;
+			if (sync_blocks < (PAGE_SIZE>>9))
+				BUG();
+			if (len > (sync_blocks<<9))
+				len = sync_blocks<<9;
 		}
 
 		for (i=0 ; i < conf->raid_disks; i++) {
@@ -1264,7 +1262,8 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 					while (i > 0) {
 						i--;
 						bio = r1_bio->bios[i];
-						if (bio->bi_end_io==NULL) continue;
+						if (bio->bi_end_io==NULL)
+							continue;
 						/* remove last page from this bio */
 						bio->bi_vcnt--;
 						bio->bi_size -= len;

include/linux/raid/bitmap.h

@@ -262,7 +262,7 @@ void bitmap_write_all(struct bitmap *bitmap);
 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors);
 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
 		     int success);
-int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks);
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int degraded);
 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted);
 void bitmap_close_sync(struct bitmap *bitmap);