From 6be1d39d1dafce71c9c7f5bc74ef3fbd30e3765e Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Tue, 4 Nov 2008 10:35:31 +1100
Subject: [PATCH] Introduce new open_mddev which just does an open.

Some cases we aren't interested in creating the mddev, just opening
it.  Make those more explicit.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 mdadm.c  |  9 +++++----
 mdadm.h  |  1 +
 mdopen.c | 31 +++++++++++++++++++++++--------
 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/mdadm.c b/mdadm.c
index fb52b14..b33f605 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -943,8 +943,9 @@ int main(int argc, char *argv[])
 			exit(2);
 		}
 		if (mode == MANAGE || mode == GROW)
-			autof=1; /* Don't create */
-		mdfd = create_mddev(devlist->devname, autof);
+			mdfd = open_mddev(devlist->devname, 1);
+		else
+			mdfd = create_mddev(devlist->devname, autof);
 		if (mdfd < 0)
 			exit(1);
 		if ((int)ident.super_minor == -2) {
@@ -1242,7 +1243,7 @@ int main(int argc, char *argv[])
 									e->dev);
 								continue;
 							}
-							mdfd = create_mddev(name, 1);
+							mdfd = open_mddev(name, 1);
 							if (mdfd >= 0) {
 								if (Manage_runstop(name, mdfd, -1, quiet?1:last?0:-1))
 									err = 1;
@@ -1279,7 +1280,7 @@ int main(int argc, char *argv[])
 				case Waitclean:
 					rv |= WaitClean(dv->devname, verbose-quiet); continue;
 				}
-				mdfd = create_mddev(dv->devname, 1);
+				mdfd = open_mddev(dv->devname, 1);
 				if (mdfd>=0) {
 					switch(dv->disposition) {
 					case 'R':
diff --git a/mdadm.h b/mdadm.h
index 8527bbb..7b7e233 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -802,6 +802,7 @@ extern char *get_md_name(int dev);
 extern char DefaultConfFile[];
 
 extern int create_mddev(char *dev, int autof);
+extern int open_mddev(char *dev, int report_errors);
 extern int create_mddev_devnum(char *devname, int devnum, char *name,
 			     char *chosen_name, int parts);
 extern int open_container(int fd);
diff --git a/mdopen.c b/mdopen.c
index 5156835..285d811 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -254,15 +254,30 @@ int create_mddev(char *dev, int autof)
 				make_parts(dev,parts, ci->symlinks);
 		}
 	}
-	mdfd = open(dev, O_RDWR);
-	if (mdfd < 0)
-		fprintf(stderr, Name ": error opening %s: %s\n",
-			dev, strerror(errno));
-	else if (md_get_version(mdfd) <= 0) {
-		fprintf(stderr, Name ": %s does not appear to be an md device\n",
-			dev);
+	mdfd = open_mddev(dev, 1);
+	return mdfd;
+}
+
+/* Open this and check that it is an md device.
+ * On success, return filedescriptor.
+ * On failure, return -1 if it doesn't exist,
+ * or -2 if it exists but is not an md device.
+ */
+int open_mddev(char *dev, int report_errors)
+{
+	int mdfd = open(dev, O_RDWR);
+	if (mdfd < 0) {
+		if (report_errors)
+			fprintf(stderr, Name ": error opening %s: %s\n",
+				dev, strerror(errno));
+		return -1;
+	}
+	if (md_get_version(mdfd) <= 0) {
 		close(mdfd);
-		mdfd = -1;
+		if (report_errors)
+			fprintf(stderr, Name ": %s does not appear to be "
+				"an md device\n", dev);
+		return -2;
 	}
 	return mdfd;
 }