From 6e6dc574d60f108fdc49f3b755d9baeec1335ba2 Mon Sep 17 00:00:00 2001
From: Neil Brown <neilb@suse.de>
Date: Mon, 5 Sep 2005 01:14:26 +0000
Subject: Fix assembling of raid10 in the face of missing devices.

We now check if enough devices are present properly, so
--force can be used to good effect.

Signed-off-by: Neil Brown <neilb@suse.de>
---
 Assemble.c | 17 ++++++++++++-----
 mdadm.h    |  3 ++-
 util.c     | 25 +++++++++++++++++++++++--
 3 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/Assemble.c b/Assemble.c
index ace5717..49639cd 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -119,6 +119,7 @@ int Assemble(char *mddev, int mdfd,
 	int start_partial_ok = force || devlist==NULL;
 	unsigned int num_devs;
 	mddev_dev_t tmpdev;
+	char *avail;
 	
 	vers = md_get_version(mdfd);
 	if (vers <= 0) {
@@ -389,6 +390,8 @@ int Assemble(char *mddev, int mdfd,
 	/* now we have some devices that might be suitable.
 	 * I wonder how many
 	 */
+	avail = malloc(first_super.raid_disks);
+	memset(avail, 0, first_super.raid_disks);
 	okcnt = 0;
 	sparecnt=0;
 	for (i=0; i< bestcnt ;i++) {
@@ -407,13 +410,16 @@ int Assemble(char *mddev, int mdfd,
 		if (devices[j].events+event_margin >=
 		    devices[most_recent].events) {
 			devices[j].uptodate = 1;
-			if (i < first_super.raid_disks)
+			if (i < first_super.raid_disks) {
 				okcnt++;
-			else
+				avail[i]=1;
+			} else
 				sparecnt++;
 		}
 	}
-	while (force && !enough(first_super.level, first_super.raid_disks, okcnt)) {
+	while (force && !enough(first_super.level, first_super.raid_disks,
+				first_super.layout,
+				avail, okcnt)) {
 		/* Choose the newest best drive which is
 		 * not up-to-date, update the superblock
 		 * and add it.
@@ -466,6 +472,7 @@ int Assemble(char *mddev, int mdfd,
 		close(fd);
 		devices[chosen_drive].events = devices[most_recent].events;
 		devices[chosen_drive].uptodate = 1;
+		avail[chosen_drive] = 1;
 		okcnt++;
 	}
 
@@ -624,7 +631,7 @@ This doesnt work yet
 		
 		if (runstop == 1 ||
 		    (runstop == 0 && 
-		     ( enough(first_super.level, first_super.raid_disks, okcnt) &&
+		     ( enough(first_super.level, first_super.raid_disks, first_super.layout, avail, okcnt) &&
 		       (okcnt >= req_cnt || start_partial_ok)
 			     ))) {
 			if (ioctl(mdfd, RUN_ARRAY, NULL)==0) {
@@ -649,7 +656,7 @@ This doesnt work yet
 		fprintf(stderr, Name ": %s assembled from %d drive%s", mddev, okcnt, okcnt==1?"":"s");
 		if (sparecnt)
 			fprintf(stderr, " and %d spare%s", sparecnt, sparecnt==1?"":"s");
-		if (!enough(first_super.level, first_super.raid_disks, okcnt))
+		if (!enough(first_super.level, first_super.raid_disks, first_super.layout, avail, okcnt))
 			fprintf(stderr, " - not enough to start the array.\n");
 		else {
 			if (req_cnt == first_super.raid_disks)
diff --git a/mdadm.h b/mdadm.h
index f4a8d20..8f0c32e 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -231,7 +231,8 @@ extern int same_uuid(int a[4], int b[4]);
 extern int compare_super(mdp_super_t *first, mdp_super_t *second);
 extern unsigned long calc_sb_csum(mdp_super_t *super);
 extern int store_super(int fd, mdp_super_t *super);
-extern int enough(int level, int raid_disks, int avail_disks);
+extern int enough(int level, int raid_disks, int layout,
+		   char *avail, int avail_disks);
 extern int ask(char *mesg);
 
 
diff --git a/util.c b/util.c
index 5bac0ec..e94edc8 100644
--- a/util.c
+++ b/util.c
@@ -118,10 +118,31 @@ int get_linux_version()
 	return (a*1000000)+(b*1000)+c;
 }
 
-int enough(int level, int raid_disks, int avail_disks)
+int enough(int level, int raid_disks, int layout,
+	   char *avail, int avail_disks)
 {
+	int copies, first;
 	switch (level) {
-	case 10: return 1; /* a lie, but it is hard to tell */
+	case 10:
+		/* This is the tricky one - we need to check
+		 * which actual disks are present.
+		 */
+		copies = (layout&255)* (layout>>8);
+		first=0;
+		do {
+			/* there must be one of the 'copies' form 'first' */
+			int n = copies;
+			int cnt=0;
+			while (n--) {
+				if (avail[first])
+					cnt++;
+				first = (first+1) % raid_disks;
+			}
+			if (cnt == 0)
+				return 0;
+
+		} while (first != 0);
+		return 1;
 
 	case -4:
 		return avail_disks>= 1;
-- 
cgit