Add a 'super-switch' so that different format superblocks can be used.

This includes:
  adding --metadata= option to choose metadata format
  adding metadata= word to config file.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>

13 files changed, 262 insertions, 99 deletions

diff --git a/Assemble.c b/Assemble.c
index e762c69..3c09861 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -29,7 +29,7 @@
 
 #include	"mdadm.h"
 
-int Assemble(char *mddev, int mdfd,
+int Assemble(struct superswitch *ss, char *mddev, int mdfd,
 	     mddev_ident_t ident, char *conffile,
 	     mddev_dev_t devlist,
 	     int readonly, int runstop,
@@ -164,6 +164,7 @@ int Assemble(char *mddev, int mdfd,
 	}
 	devices = malloc(num_devs * sizeof(*devices));
 
+	if (!ss && ident->ss) ss = ident->ss;
 
 	if (verbose)
 	    fprintf(stderr, Name ": looking for devices for %s\n",
@@ -173,6 +174,7 @@ int Assemble(char *mddev, int mdfd,
 		char *devname;
 		int dfd;
 		struct stat stb;
+		struct superswitch *tss = ss;
 
 		devname = devlist->devname;
 		devlist = devlist->next;
@@ -203,13 +205,16 @@ int Assemble(char *mddev, int mdfd,
 			fprintf(stderr, Name ": %s is not a block device.\n",
 				devname);
 			close(dfd);
-		} else if (load_super0(dfd, &super, NULL)) {
+		} else if (!tss && (tss = guess_super(dfd, NULL)) == NULL) {
+			if (inargv || verbose)
+				fprintf(stderr, Name ": no recogniseable superblock\n");
+		} else if (tss->load_super(dfd, &super, NULL)) {
 			if (inargv || verbose)
 				fprintf( stderr, Name ": no RAID superblock on %s\n",
 					 devname);
 			close(dfd);
 		} else {
-			getinfo_super0(&info, super);
+			tss->getinfo_super(&info, super);
 			close(dfd);
 		}
 
@@ -253,7 +258,8 @@ int Assemble(char *mddev, int mdfd,
 			free(first_super);
 			return 1;
 		}
-		if (compare_super0(&first_super, super)) {
+		ss = tss; /* commit to this format, if haven't already */
+		if (ss->compare_super(&first_super, super)) {
 			fprintf(stderr, Name ": superblock on %s doesn't match others - assembly aborted\n",
 				devname);
 			free(super);
@@ -268,13 +274,13 @@ int Assemble(char *mddev, int mdfd,
 			fstat(mdfd, &stb2);
 			info.array.md_minor = minor(stb2.st_rdev);
 			
-			update_super0(&info, super, update, devname, verbose);
+			ss->update_super(&info, super, update, devname, verbose);
 			
 			dfd = open(devname, O_RDWR|O_EXCL, 0);
 			if (dfd < 0) 
 				fprintf(stderr, Name ": Cannot open %s for superblock update\n",
 					devname);
-			else if (store_super0(dfd, super))
+			else if (ss->store_super(dfd, super))
 				fprintf(stderr, Name ": Could not re-write superblock on %s.\n",
 					devname);
 			if (dfd >= 0)
@@ -335,7 +341,7 @@ int Assemble(char *mddev, int mdfd,
 		return 1;
 	}
 
-	getinfo_super0(&info, first_super);
+	ss->getinfo_super(&info, first_super);
 
 	/* now we have some devices that might be suitable.
 	 * I wonder how many
@@ -393,7 +399,7 @@ int Assemble(char *mddev, int mdfd,
 			devices[chosen_drive].events = 0;
 			continue;
 		}
-		if (load_super0(fd, &super, NULL)) {
+		if (ss->load_super(fd, &super, NULL)) {
 			close(fd);
 			fprintf(stderr, Name ": RAID superblock disappeared from %s - not updating.\n",
 				devices[chosen_drive].devname);
@@ -401,9 +407,9 @@ int Assemble(char *mddev, int mdfd,
 			continue;
 		}
 		info.events = devices[most_recent].events;
-		update_super0(&info, super, "force", devices[chosen_drive].devname, verbose);
+		ss->update_super(&info, super, "force", devices[chosen_drive].devname, verbose);
 
-		if (store_super0(fd, super)) {
+		if (ss->store_super(fd, super)) {
 			close(fd);
 			fprintf(stderr, Name ": Could not re-write superblock on %s\n",
 				devices[chosen_drive].devname);
@@ -440,7 +446,7 @@ int Assemble(char *mddev, int mdfd,
 				devices[j].devname, strerror(errno));
 			return 1;
 		}
-		if (load_super0(fd, &super, NULL)) {
+		if (ss->load_super(fd, &super, NULL)) {
 			close(fd);
 			fprintf(stderr, Name ": RAID superblock has disappeared from %s\n",
 				devices[j].devname);
@@ -452,7 +458,7 @@ int Assemble(char *mddev, int mdfd,
 		fprintf(stderr, Name ": No suitable drives found for %s\n", mddev);
 		return 1;
 	}
-	getinfo_super0(&info, super);
+	ss->getinfo_super(&info, super);
 	for (i=0; i<bestcnt; i++) {
 		int j = best[i];
 		unsigned int desired_state;
@@ -470,7 +476,7 @@ int Assemble(char *mddev, int mdfd,
 		info.disk.state = desired_state;
 
 		if (devices[j].uptodate &&
-		    update_super0(&info, super, "assemble", NULL, 0)) {
+		    ss->update_super(&info, super, "assemble", NULL, 0)) {
 			if (force) {
 				fprintf(stderr, Name ": "
 					"clearing FAULTY flag for device %d in %s for %s\n",
@@ -492,7 +498,7 @@ int Assemble(char *mddev, int mdfd,
 	}
 	if (force && okcnt == info.array.raid_disks-1) {
 		/* FIXME check event count */
-		change += update_super0(&info, super, "force", 
+		change += ss->update_super(&info, super, "force", 
 					devices[chosen_drive].devname, 0);
 	}
 
@@ -504,7 +510,7 @@ int Assemble(char *mddev, int mdfd,
 				devices[chosen_drive].devname);
 			return 1;
 		}
-		if (store_super0(fd, super)) {
+		if (ss->store_super(fd, super)) {
 			close(fd);
 			fprintf(stderr, Name ": Could not re-write superblock on %s\n",
 				devices[chosen_drive].devname);
diff --git a/Create.c b/Create.c
index 87a275e..15a7de8 100644
--- a/Create.c
+++ b/Create.c
@@ -31,7 +31,7 @@
 #include	"md_u.h"
 #include	"md_p.h"
 
-int Create(char *mddev, int mdfd,
+int Create(struct superswitch *ss, char *mddev, int mdfd,
 	   int chunk, int level, int layout, unsigned long size, int raiddisks, int sparedisks,
 	   int subdevs, mddev_dev_t devlist,
 	   int runstop, int verbose, int force)
@@ -349,7 +349,7 @@ int Create(char *mddev, int mdfd,
 		return 1;
 	}
 
-	init_super0(&super, &array);
+	ss->init_super(&super, &array);
 
 
 	for (pass=1; pass <=2 ; pass++) {
@@ -389,10 +389,10 @@ int Create(char *mddev, int mdfd,
 			}
 			switch(pass){
 			case 1:
-				add_to_super0(super, &disk);
+				ss->add_to_super(super, &disk);
 				break;
 			case 2:
-				write_init_super0(super, &disk, dv->devname);
+				ss->write_init_super(super, &disk, dv->devname);
 
 				if (ioctl(mdfd, ADD_NEW_DISK, &disk)) {
 					fprintf(stderr, Name ": ADD_NEW_DISK for %s failed: %s\n",
diff --git a/Detail.c b/Detail.c
index 59b091f..2f3fc7f 100644
--- a/Detail.c
+++ b/Detail.c
@@ -50,6 +50,7 @@ int Detail(char *dev, int brief, int test)
 	int is_26 = get_linux_version() >= 2006000;
 	int is_rebuilding = 0;
 	int failed = 0;
+	struct superswitch *ss = NULL;
 
 	void *super = NULL;
 	int rv = test ? 4 : 1;
@@ -82,6 +83,8 @@ int Detail(char *dev, int brief, int test)
 		close(fd);
 		return rv;
 	}
+	ss = super_by_version(array.major_version);
+
 	if (fstat(fd, &stb) != 0 && !S_ISBLK(stb.st_mode))
 		stb.st_rdev = 0;
 	rv = 0;
@@ -103,10 +106,10 @@ int Detail(char *dev, int brief, int test)
 				 * to get more info
 				 */
 				int fd2 = open(dv, O_RDONLY);
-				if (fd2 >=0 &&
-				    load_super0(fd2, &super, NULL) == 0) {
+				if (fd2 >=0 && ss &&
+				    ss->load_super(fd2, &super, NULL) == 0) {
 					struct mdinfo info;
-					getinfo_super0(&info, super);
+					ss->getinfo_super(&info, super);
 					if (info.array.ctime != array.ctime ||
 					    info.array.level != array.level) {
 						free(super);
@@ -202,8 +205,8 @@ int Detail(char *dev, int brief, int test)
 		}
 		free_mdstat(ms);
 
-		if (super)
-			detail_super0(super);
+		if (super && ss)
+			ss->detail_super(super);
 
 		printf("    Number   Major   Minor   RaidDevice State\n");
 	}
@@ -275,8 +278,8 @@ int Detail(char *dev, int brief, int test)
 		if (!brief) printf("\n");
 	}
 	if (spares && brief) printf(" spares=%d", spares);
-	if (super && brief)
-		brief_detail_super0(super);
+	if (super && brief && ss)
+		ss->brief_detail_super(super);
 
 	if (brief && devices) printf("\n   devices=%s", devices);
 	if (brief) printf("\n");
diff --git a/Examine.c b/Examine.c
index cd79583..8081b66 100644
--- a/Examine.c
+++ b/Examine.c
@@ -60,6 +60,7 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 
 	struct array {
 		void *super;
+		struct superswitch *ss;
 		struct mdinfo info;
 		void *devs;
 		struct array *next;
@@ -67,6 +68,8 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 	} *arrays = NULL;
 
 	for (; devlist ; devlist=devlist->next) {
+		struct superswitch *ss;
+
 		fd = open(devlist->devname, O_RDONLY);
 		if (fd < 0) {
 			if (!scan)
@@ -75,7 +78,11 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 			err = 1;
 		}
 		else {
-			err = load_super0(fd, &super, (brief||scan)?NULL:devlist->devname);
+			ss = guess_super(fd, devlist->devname);
+			if (ss)
+				err = ss->load_super(fd, &super, (brief||scan)?NULL:devlist->devname);
+			else
+				err = 1;
 			close(fd);
 		}
 		if (err)
@@ -83,13 +90,13 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 		if (err) rv =1;
 
 		if (SparcAdjust)
-			update_super0(NULL, super, "sparc2.2", devlist->devname, 0);
+			ss->update_super(NULL, super, "sparc2.2", devlist->devname, 0);
 		/* Ok, its good enough to try, though the checksum could be wrong */
 		if (brief) {
 			struct array *ap;
 			char *d;
 			for (ap=arrays; ap; ap=ap->next) {
-				if (compare_super0(&ap->super, super)==0)
+				if (ss == ap->ss && ss->compare_super(&ap->super, super)==0)
 					break;
 			}
 			if (!ap) {
@@ -98,10 +105,11 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 				ap->devs = dl_head();
 				ap->next = arrays;
 				ap->spares = 0;
+				ap->ss = ss;
 				arrays = ap;
-				getinfo_super0(&ap->info, super);
+				ss->getinfo_super(&ap->info, super);
 			} else {
-				getinfo_super0(&ap->info, super);
+				ss->getinfo_super(&ap->info, super);
 				free(super);
 			}
 			if (!(ap->info.disk.state & MD_DISK_SYNC))
@@ -110,7 +118,7 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 			dl_add(ap->devs, d);
 		} else {
 			printf("%s:\n",devlist->devname);
-			examine_super0(super);
+			ss->examine_super(super);
 			free(super);
 		}
 	}
@@ -119,7 +127,7 @@ int Examine(mddev_dev_t devlist, int brief, int scan, int SparcAdjust)
 		for (ap=arrays; ap; ap=ap->next) {
 			char sep='=';
 			char *d;
-			brief_examine_super0(ap->super);
+			ap->ss->brief_examine_super(ap->super);
 			if (ap->spares) printf("   spares=%d", ap->spares);
 			printf("   devices");
 			for (d=dl_next(ap->devs); d!= ap->devs; d=dl_next(d)) {
diff --git a/Grow.c b/Grow.c
index 8de28d4..ec2eb55 100644
--- a/Grow.c
+++ b/Grow.c
@@ -51,6 +51,7 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 	struct stat stb;
 	int nfd, fd2;
 	int d, nd;
+	struct superswitch *ss = NULL;
 	
 
 	if (ioctl(fd, GET_ARRAY_INFO, &info.array) < 0) {
@@ -58,6 +59,12 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 		return 1;
 	}
 
+	ss = super_by_version(info.array.major_version);
+	if (!ss) {
+		fprintf(stderr, Name ": cannot handle arrays with superblock version %d\n", info.array.major_version);
+		return 1;
+	}
+
 	if (info.array.level != -1) {
 		fprintf(stderr, Name ": can only add devices to linear arrays\n");
 		return 1;
@@ -98,7 +105,7 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 		}
 		if (super) free(super);
 		super= NULL;
-		if (load_super0(fd2, &super, NULL)) {
+		if (ss->load_super(fd2, &super, NULL)) {
 			fprintf(stderr, Name ": cannot find super block on %s\n", dv);
 			close(fd2);
 			return 1;
@@ -114,9 +121,9 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 	info.disk.minor = minor(stb.st_rdev);
 	info.disk.raid_disk = d;
 	info.disk.state = (1 << MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE);
-	update_super0(&info, super, "grow", newdev, 0);
+	ss->update_super(&info, super, "grow", newdev, 0);
 
-	if (store_super0(nfd, super)) {
+	if (ss->store_super(nfd, super)) {
 		fprintf(stderr, Name ": Cannot store new superblock on %s\n", newdev);
 		close(nfd);
 		return 1;
@@ -158,7 +165,7 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 			fprintf(stderr, Name ": cannot open device file %s\n", dv);
 			return 1;
 		}
-		if (load_super0(fd2, &super, NULL)) {
+		if (ss->load_super(fd2, &super, NULL)) {
 			fprintf(stderr, Name ": cannot find super block on %s\n", dv);
 			close(fd);
 			return 1;
@@ -172,9 +179,9 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 		info.disk.minor = minor(stb.st_rdev);
 		info.disk.raid_disk = nd;
 		info.disk.state = (1 << MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE);
-		update_super0(&info, super, "grow", dv, 0);
+		ss->update_super(&info, super, "grow", dv, 0);
 		
-		if (store_super0(fd2, super)) {
+		if (ss->store_super(fd2, super)) {
 			fprintf(stderr, Name ": Cannot store new superblock on %s\n", dv);
 			close(fd2);
 			return 1;
diff --git a/Kill.c b/Kill.c
index fbda686..b20c28e 100644
--- a/Kill.c
+++ b/Kill.c
@@ -43,19 +43,28 @@ int Kill(char *dev, int force)
 
 	void *super;
 	int fd, rv = 0;
+	struct superswitch *ss;
 		
 	fd = open(dev, O_RDWR|O_EXCL);
 	if (fd < 0) {
 		fprintf(stderr, Name ": Couldn't open %s for write - not zeroing\n",
 			dev);
 		return 1;
-	} 
-	rv = load_super0(fd, &super, dev);
+	}
+	ss = guess_super(fd, dev);
+	if (ss == NULL) {
+		fprintf(stderr, Name ": Unrecognised md component device - %s\n", dev);
+		return 1;
+	}
+	rv = ss->load_super(fd, &super, dev);
 	if (force && rv >= 2)
 		rv = 0; /* ignore bad data in superblock */
 	if (rv== 0 || (force && rv >= 2)) {
-		memset(&super, 0, sizeof(super));
-		if (store_super0(fd, super)) {
+		mdu_array_info_t info;
+		info.major_version = -1; /* zero superblock */
+		free(super);
+		ss->init_super(&super, &info);
+		if (ss->store_super(fd, super)) {
 			fprintf(stderr, Name ": Could not zero superblock on %s\n",
 				dev);
 			rv = 1;
diff --git a/Query.c b/Query.c
index 71aafd8..88df321 100644
--- a/Query.c
+++ b/Query.c
@@ -44,6 +44,7 @@ int Query(char *dev)
 	struct mdinfo info;
 	mdu_array_info_t array;
 	void *super;
+	struct superswitch *ss = NULL;
 
 	unsigned long long larray_size;
 	unsigned long array_size;
@@ -94,12 +95,16 @@ int Query(char *dev)
 		       array.raid_disks,
 		       array.spare_disks, array.spare_disks==1?"":"s");
 	}
-	superror = load_super0(fd, &super, dev);
-	superrno = errno;
+	ss = guess_super(fd, dev);
+	if (ss) {
+		superror = ss->load_super(fd, &super, dev);
+		superrno = errno;
+	} else 
+		superror = -1;
 	close(fd);
 	if (superror == 0) {
 		/* array might be active... */
-		getinfo_super0(&info, super);
+		ss->getinfo_super(&info, super);
 		mddev = get_md_name(info.array.md_minor);
 		disc.number = info.disk.number;
 		activity = "undetected";
diff --git a/ReadMe.c b/ReadMe.c
index 00283e9..367bc0b 100644
--- a/ReadMe.c
+++ b/ReadMe.c
@@ -91,7 +91,7 @@ char Version[] = Name " - v1.11.0 - 11 April 2005\n";
  *     At the time if writing, there is only minimal support.
  */
 
-char short_options[]="-ABCDEFGQhVvbc:i:l:p:m:n:x:u:c:d:z:U:sa::rfRSow1t";
+char short_options[]="-ABCDEFGQhVvbc:i:l:p:m:n:x:u:c:d:z:U:sa::rfRSow1te:";
 struct option long_options[] = {
     {"manage",    0, 0, '@'},
     {"misc",      0, 0, '#'},
@@ -127,6 +127,7 @@ struct option long_options[] = {
     {"size",	  1, 0, 'z'},
     {"auto",	  2, 0, 'a'}, /* also for --assemble */
     {"assume-clean",0,0, 3 },
+    {"metadata",  1, 0, 'e'}, /* superblock format */
 
     /* For assemble */
     {"uuid",      1, 0, 'u'},
diff --git a/config.c b/config.c
index 0aac1a0..f3a749c 100644
--- a/config.c
+++ b/config.c
@@ -328,6 +328,17 @@ void arrayline(char *line)
 		} else if (strncasecmp(w, "spares=", 7) == 0 ) {
 			/* for warning if not all spares present */
 			mis.spare_disks = atoi(w+7);
+		} else if (strncasecmp(w, "metadata=", 9) == 0) {
+			/* style of metadata on the devices. */
+			int i;
+			
+			for(i=0; superlist[i]; i++) 
+				if (superlist[i]->match_metadata_desc(w+9)) {
+					mis.ss = superlist[i];
+					break;
+				}
+			if (!mis.ss)
+				fprintf(stderr, Name ": metadata format %s unknown, ignored.\n", w+9);
 		} else if (strncasecmp(w, "auto=", 5) == 0 ) {
 			/* whether to create device special files as needed */
 			if (strcasecmp(w+5, "no")==0)
diff --git a/mdadm.c b/mdadm.c
index daf2412..b738fad 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -32,7 +32,6 @@
 #include <ctype.h>
 
 
-
 int main(int argc, char *argv[])
 {
 	int mode = 0;
@@ -41,6 +40,7 @@ int main(int argc, char *argv[])
 	char *help_text;
 	char *c;
 	int rv;
+	int i;
 
 	int chunk = 0;
 	int size = -1;
@@ -81,6 +81,7 @@ int main(int argc, char *argv[])
 	int daemonise = 0;
 	char *pidfile = NULL;
 	int oneshot = 0;
+	struct superswitch *ss = NULL;
 
 	int copies;
 
@@ -273,6 +274,24 @@ int main(int argc, char *argv[])
 			}
 			continue;
 
+		case O(CREATE,'e'):
+		case O(ASSEMBLE,'e'):
+		case O(MISC,'e'): /* set metadata (superblock) information */
+			if (ss) {
+				fprintf(stderr, Name ": metadata information already given\n");
+				exit(2);
+			}
+			for(i=0; superlist[i]; i++) 
+				if (superlist[i]->match_metadata_desc(optarg)) {
+					ss = superlist[i];
+					break;
+				}
+			if (!ss) {
+				fprintf(stderr, Name ": unrecognised metadata identifier: %s\n", optarg);
+				exit(2);
+			}
+			continue;
+
 		case O(GROW,'z'):
 		case O(CREATE,'z'): /* size */
 			if (size >= 0) {
@@ -736,14 +755,14 @@ int main(int argc, char *argv[])
 				if (mdfd < 0)
 					rv |= 1;
 				else {
-					rv |= Assemble(devlist->devname, mdfd, array_ident, configfile,
+					rv |= Assemble(ss, devlist->devname, mdfd, array_ident, configfile,
 						       NULL,
 						       readonly, runstop, update, verbose, force);
 					close(mdfd);
 				}
 			}
 		} else if (!scan)
-			rv = Assemble(devlist->devname, mdfd, &ident, configfile,
+			rv = Assemble(ss, devlist->devname, mdfd, &ident, configfile,
 				      devlist->next,
 				      readonly, runstop, update, verbose, force);
 		else if (devs_found>0) {
@@ -764,7 +783,7 @@ int main(int argc, char *argv[])
 					rv |= 1;
 					continue;
 				}
-				rv |= Assemble(dv->devname, mdfd, array_ident, configfile,
+				rv |= Assemble(ss, dv->devname, mdfd, array_ident, configfile,
 					       NULL,
 					       readonly, runstop, update, verbose, force);
 				close(mdfd);
@@ -786,7 +805,7 @@ int main(int argc, char *argv[])
 						/* already assembled, skip */
 						;
 					else
-						rv |= Assemble(array_list->devname, mdfd,
+						rv |= Assemble(ss, array_list->devname, mdfd,
 							       array_list, configfile,
 							       NULL,
 							       readonly, runstop, NULL, verbose, force);
@@ -798,7 +817,19 @@ int main(int argc, char *argv[])
 		rv = Build(devlist->devname, mdfd, chunk, level, layout, raiddisks, devlist->next, assume_clean);
 		break;
 	case CREATE:
-		rv = Create(devlist->devname, mdfd, chunk, level, layout, size<0 ? 0 : size,
+		if (ss == NULL) {
+			for(i=0; superlist[i]; i++) 
+				if (superlist[i]->match_metadata_desc("default")) {
+					ss = superlist[i];
+					break;
+				}
+		}
+		if (!ss) {
+			fprintf(stderr, Name ": internal error - no default metadata style\n");
+			exit(2);
+		}
+
+		rv = Create(ss, devlist->devname, mdfd, chunk, level, layout, size<0 ? 0 : size,
 			    raiddisks, sparedisks,
 			    devs_found-1, devlist->next, runstop, verbose, force);
 		break;
diff --git a/mdadm.h b/mdadm.h
index 6638a34..491d907 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -116,6 +116,7 @@ typedef struct mddev_ident_s {
 	int	level;
 	unsigned int raid_disks;
 	unsigned int spare_disks;
+	struct superswitch *ss;
 	int	autof;		/* 1 for normal, 2 for partitioned */
 	char	*spare_group;
 
@@ -163,6 +164,28 @@ extern mapping_t r5layout[], pers[], modes[], faultylayout[];
 extern char *map_dev(int major, int minor);
 
 
+extern struct superswitch {
+	void (*examine_super)(void *sbv);
+	void (*brief_examine_super)(void *sbv);
+	void (*detail_super)(void *sbv);
+	void (*brief_detail_super)(void *sbv);
+	void (*uuid_from_super)(int uuid[4], void *sbv);
+	void (*getinfo_super)(struct mdinfo *info, void *sbv);
+	int (*update_super)(struct mdinfo *info, void *sbv, char *update, char *devname, int verbose);
+	__u64 (*event_super)(void *sbv);
+	void (*init_super)(void **sbp, mdu_array_info_t *info);
+	void (*add_to_super)(void *sbv, mdu_disk_info_t *dinfo);
+	int (*store_super)(int fd, void *sbv);
+	int (*write_init_super)(void *sbv, mdu_disk_info_t *dinfo, char *devname);
+	int (*compare_super)(void **firstp, void *secondv);
+	int (*load_super)(int fd, void **sbp, char *devname);
+	int (*match_metadata_desc)(char *arg);
+} super0, *superlist[];
+
+extern struct superswitch *super_by_version(int vers);
+extern struct superswitch *guess_super(int fd, char *dev);
+
+
 extern int Manage_ro(char *devname, int fd, int readonly);
 extern int Manage_runstop(char *devname, int fd, int runstop);
 extern int Manage_resize(char *devname, int fd, long long size, int raid_disks);
@@ -172,7 +195,7 @@ extern int Manage_subdevs(char *devname, int fd,
 extern int Grow_Add_device(char *devname, int fd, char *newdev);
 
 
-extern int Assemble(char *mddev, int mdfd,
+extern int Assemble(struct superswitch *ss, char *mddev, int mdfd,
 		    mddev_ident_t ident,
 		    char *conffile,
 		    mddev_dev_t devlist,
@@ -185,7 +208,7 @@ extern int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 		 mddev_dev_t devlist, int assume_clean);
 
 
-extern int Create(char *mddev, int mdfd,
+extern int Create(struct superswitch *ss, char *mddev, int mdfd,
 		  int chunk, int level, int layout, unsigned long size, int raiddisks, int sparedisks,
 		  int subdevs, mddev_dev_t devlist,
 		  int runstop, int verbose, int force);
@@ -262,18 +285,3 @@ extern int open_mddev(char *dev, int autof);
 
 #define	ModeMask	0x1f
 #define	ModeShift	5
-
-extern void examine_super0(void *sbv);
-extern void brief_examine_super0(void *sbv);
-extern void detail_super0(void *sbv);
-extern void brief_detail_super0(void *sbv);
-extern void getinfo_super0(struct mdinfo *info, void *sbv);
-extern int update_super0(struct mdinfo *info, void *sbv, char *update, char *devname, int verbose);
-extern __u64 event_super0(void *sbv);
-extern void uuid_from_super0(int uuid[4], void * sbv);
-extern void init_super0(void **sbv, mdu_array_info_t *info);
-extern void add_to_super0(void *sbp, mdu_disk_info_t *dinfo);
-extern int store_super0(int fd, mdp_super_t *super);
-extern int write_init_super0(void *sbv, mdu_disk_info_t *dinfo, char *devname);
-extern int load_super0(int fd, void **super, char *devname);
-extern int compare_super0(void **first, void *second);
diff --git a/super0.c b/super0.c
index a65d1e1..4cd2cc3 100644
--- a/super0.c
+++ b/super0.c
@@ -51,7 +51,7 @@ static unsigned long calc_sb0_csum(mdp_super_t *super)
 	return newcsum;
 }
 
-void examine_super0(void *sbv)
+static void examine_super0(void *sbv)
 {
 	mdp_super_t *sb = sbv;
 	time_t atime;
@@ -129,7 +129,7 @@ void examine_super0(void *sbv)
 	}
 }
 
-void brief_examine_super0(void *sbv)
+static void brief_examine_super0(void *sbv)
 {
 	mdp_super_t *sb = sbv;
 	char *c=map_num(pers, sb->level);
@@ -145,7 +145,7 @@ void brief_examine_super0(void *sbv)
 	printf("\n");
 }
 
-void detail_super0(void *sbv)
+static void detail_super0(void *sbv)
 {
 	mdp_super_t *sb = sbv;
 	printf("           UUID : ");
@@ -157,7 +157,7 @@ void detail_super0(void *sbv)
 	printf("\n         Events : %d.%d\n\n", sb->events_hi, sb->events_lo);
 }
 
-void brief_detail_super0(void *sbv)
+static void brief_detail_super0(void *sbv)
 {
 	mdp_super_t *sb = sbv;
 	printf(" UUID=");
@@ -168,7 +168,7 @@ void brief_detail_super0(void *sbv)
 		printf("%08x", sb->set_uuid0);
 }
 
-void uuid_from_super0(int uuid[4], void * sbv)
+static void uuid_from_super0(int uuid[4], void * sbv)
 {
 	mdp_super_t *super = sbv;
 	uuid[0] = super->set_uuid0;
@@ -183,7 +183,7 @@ void uuid_from_super0(int uuid[4], void * sbv)
 	}
 }
 
-void getinfo_super0(struct mdinfo *info, void *sbv)
+static void getinfo_super0(struct mdinfo *info, void *sbv)
 {
 	mdp_super_t *sb = sbv;
 	int working = 0;
@@ -216,7 +216,7 @@ void getinfo_super0(struct mdinfo *info, void *sbv)
 }
 
 
-int update_super0(struct mdinfo *info, void *sbv, char *update, char *devname, int verbose)
+static int update_super0(struct mdinfo *info, void *sbv, char *update, char *devname, int verbose)
 {
 	int rv = 0;
 	mdp_super_t *sb = sbv;
@@ -314,7 +314,7 @@ int update_super0(struct mdinfo *info, void *sbv, char *update, char *devname, i
 	return rv;
 }
 
-__u64 event_super0(void *sbv)
+static __u64 event_super0(void *sbv)
 {
 	mdp_super_t *sb = sbv;
 	return md_event(sb);
@@ -322,11 +322,16 @@ __u64 event_super0(void *sbv)
 
 
 
-void init_super0(void **sbp, mdu_array_info_t *info)
+static void init_super0(void **sbp, mdu_array_info_t *info)
 {
 	mdp_super_t *sb = malloc(MD_SB_BYTES);
 	memset(sb, 0, MD_SB_BYTES);
 
+	if (info->major_version == -1) {
+		/* zeroing the superblock */
+		return;
+	}
+
 	sb->md_magic = MD_SB_MAGIC;
 	sb->major_version = 0;
 	sb->minor_version = 90;
@@ -359,7 +364,7 @@ void init_super0(void **sbp, mdu_array_info_t *info)
 }
 
 /* Add a device to the superblock being created */
-void add_to_super0(void *sbv, mdu_disk_info_t *dinfo)
+static void add_to_super0(void *sbv, mdu_disk_info_t *dinfo)
 {
 	mdp_super_t *sb = sbv;
 	mdp_disk_t *dk = &sb->disks[dinfo->number];
@@ -371,11 +376,12 @@ void add_to_super0(void *sbv, mdu_disk_info_t *dinfo)
 	dk->state = dinfo->state;
 }
 
-int store_super0(int fd, mdp_super_t *super)
+static int store_super0(int fd, void *sbv)
 {
 	unsigned long size;
 	unsigned long long dsize;
 	unsigned long long offset;
+	mdp_super_t *super = sbv;
     
 #ifdef BLKGETSIZE64
 	if (ioctl(fd, BLKGETSIZE64, &dsize) != 0)
@@ -403,7 +409,7 @@ int store_super0(int fd, mdp_super_t *super)
 	return 0;
 }
 
-int write_init_super0(void *sbv, mdu_disk_info_t *dinfo, char *devname)
+static int write_init_super0(void *sbv, mdu_disk_info_t *dinfo, char *devname)
 {
 	mdp_super_t *sb = sbv;
 	int fd = open(devname, O_RDWR, O_EXCL);
@@ -423,7 +429,7 @@ int write_init_super0(void *sbv, mdu_disk_info_t *dinfo, char *devname)
 	return rv;
 }
 
-int compare_super0(void **firstp, void *secondv)
+static int compare_super0(void **firstp, void *secondv)
 {
 	/*
 	 * return:
@@ -463,7 +469,7 @@ int compare_super0(void **firstp, void *secondv)
 }
 
 
-int load_super0(int fd, void **sbp, char *devname)
+static int load_super0(int fd, void **sbp, char *devname)
 {
 	/* try to read in the superblock
 	 * Return:
@@ -537,3 +543,31 @@ int load_super0(int fd, void **sbp, char *devname)
 	*sbp = super;
 	return 0;
 }
+
+static int match_metadata_desc0(char *arg)
+{
+	if (strcmp(arg, "0") == 0 ||
+	    strcmp(arg, "0.90") == 0 ||
+	    strcmp(arg, "default") == 0
+		)
+		return 1;
+	return 0;
+}
+
+struct superswitch super0 = {
+	.examine_super = examine_super0,
+	.brief_examine_super = brief_examine_super0,
+	.detail_super = detail_super0,
+	.brief_detail_super = brief_detail_super0,
+	.uuid_from_super = uuid_from_super0,
+	.getinfo_super = getinfo_super0,
+	.update_super = update_super0,
+	.event_super = event_super0,
+	.init_super = init_super0,
+	.add_to_super = add_to_super0,
+	.store_super = store_super0,
+	.write_init_super = write_init_super0,
+	.compare_super = compare_super0,
+	.load_super = load_super0,
+	.match_metadata_desc = match_metadata_desc0,
+};
diff --git a/util.c b/util.c
index e9bce2a..f243d88 100644
--- a/util.c
+++ b/util.c
@@ -205,26 +205,27 @@ int check_reiser(int fd, char *name)
 	return 1;
 }
 
-int load_super(int fd, void **sbp, int vers)
-{
-	return load_super0(fd, sbp, NULL);
-}
 int check_raid(int fd, char *name)
 {
 	void *super;
 	struct mdinfo info;
 	time_t crtime;
-	if (load_super(fd, &super, -1))
-		return 0;
-	/* Looks like a raid array .. */
-	fprintf(stderr, Name ": %s appears to be part of a raid array:\n",
-		name);
-	getinfo_super0(&info, super);
-	free(super);
-	crtime = info.array.ctime;
-	fprintf(stderr, "    level=%d devices=%d ctime=%s",
-		info.array.level, info.array.raid_disks, ctime(&crtime));
-	return 1;
+
+	int i;
+	for (i=0; superlist[i]; i++) {
+		if (superlist[i]->load_super(fd, &super, name))
+			continue;
+		/* Looks like a raid array .. */
+		fprintf(stderr, Name ": %s appears to be part of a raid array:\n",
+			name);
+		superlist[i]->getinfo_super(&info, super);
+		free(super);
+		crtime = info.array.ctime;
+		fprintf(stderr, "    level=%d devices=%d ctime=%s",
+			info.array.level, info.array.raid_disks, ctime(&crtime));
+		return 1;
+	}
+	return 0;
 }
 
 
@@ -521,3 +522,42 @@ void put_md_name(char *name)
 	if (strncmp(name, "/dev/.tmp.md", 12)==0)
 		unlink(name);
 }
+
+
+
+
+struct superswitch *superlist[] = { &super0, NULL };
+
+struct superswitch *super_by_version(int vers)
+{
+	if (vers == 0) return &super0;
+	return NULL;
+}
+
+struct superswitch *guess_super(int fd, char *dev)
+{
+	/* try each load_super to find the best match,
+	 * and return the best superswitch
+	 */
+	struct superswitch *best = NULL, *ss;
+	int bestrv = 0;
+	void *sbp = NULL;
+	int i;
+
+	for (i=0 ; superlist[i]; i++) {
+		int rv;
+		ss = superlist[i];
+		rv = ss->load_super(fd, &sbp, NULL);
+		if (rv == 0) {
+			free(sbp);
+			return ss;
+		}
+		if (rv > bestrv) {
+			bestrv  = rv;
+			best = ss;
+		}
+	}
+	if (bestrv > 2) /* FIXME */
+		return best;
+	return NULL;
+}