[PATCH] MD - Remove dependance on superblock

Remove dependance on superblock

All the remaining field of interest in the superblock
get duplicated in the mddev struture and this is treated as
authoritative.  The superblock gets completely generated at
write time, and all useful information extracted at read time.

This means that we can slot in different superblock formats
without affecting the bulk of the code.

drivers/md/linear.c

@@ -55,7 +55,7 @@ static int linear_run (mddev_t *mddev)
 		int j = rdev->raid_disk;
 		dev_info_t *disk = conf->disks + j;
 
-		if (j < 0 || j > mddev->sb->raid_disks || disk->bdev) {
+		if (j < 0 || j > mddev->raid_disks || disk->bdev) {
 			printk("linear: disk numbering problem. Aborting!\n");
 			goto out;
 		}
@@ -67,7 +67,7 @@ static int linear_run (mddev_t *mddev)
 			conf->smallest = disk;
 		cnt++;
 	}
-	if (cnt != mddev->sb->raid_disks) {
+	if (cnt != mddev->raid_disks) {
 		printk("linear: not enough drives present. Aborting!\n");
 		goto out;
 	}
@@ -186,7 +186,7 @@ static int linear_status (char *page, mddev_t *mddev)
 	}
 	sz += sprintf(page+sz, "\n");
 #endif
-	sz += sprintf(page+sz, " %dk rounding", mddev->sb->chunk_size/1024);
+	sz += sprintf(page+sz, " %dk rounding", mddev->chunk_size/1024);
 	return sz;
 }
 

drivers/md/multipath.c

@@ -424,7 +424,7 @@ static void multipathd (void *data)
 "multipath: detected IO path differences!\n"
 
 #define ARRAY_IS_ACTIVE KERN_INFO \
-"multipath: array md%d active with %d out of %d IO paths (%d spare IO paths)\n"
+"multipath: array md%d active with %d out of %d IO paths\n"
 
 #define THREAD_ERROR KERN_ERR \
 "multipath: couldn't allocate thread for md%d\n"
@@ -434,15 +434,14 @@ static int multipath_run (mddev_t *mddev)
 	multipath_conf_t *conf;
 	int disk_idx;
 	struct multipath_info *disk;
-	mdp_super_t *sb = mddev->sb;
 	mdk_rdev_t *rdev;
 	struct list_head *tmp;
 	int num_rdevs = 0;
 
 	MOD_INC_USE_COUNT;
 
-	if (sb->level != LEVEL_MULTIPATH) {
-		printk(INVALID_LEVEL, mdidx(mddev), sb->level);
+	if (mddev->level != LEVEL_MULTIPATH) {
+		printk(INVALID_LEVEL, mdidx(mddev), mddev->level);
 		goto out;
 	}
 	/*
@@ -492,7 +491,7 @@ static int multipath_run (mddev_t *mddev)
 		num_rdevs++;
 	}
 
-	conf->raid_disks = sb->raid_disks = num_rdevs;
+	conf->raid_disks = mddev->raid_disks = num_rdevs;
 	mddev->sb_dirty = 1;
 	conf->mddev = mddev;
 	conf->device_lock = SPIN_LOCK_UNLOCKED;
@@ -520,8 +519,8 @@ static int multipath_run (mddev_t *mddev)
 		}
 	}
 
-	printk(ARRAY_IS_ACTIVE, mdidx(mddev), sb->active_disks,
-			sb->raid_disks, sb->spare_disks);
+	printk(ARRAY_IS_ACTIVE, mdidx(mddev), conf->working_disks,
+			mddev->raid_disks);
 	/*
 	 * Ok, everything is just fine now
 	 */

drivers/md/raid0.c

@@ -89,7 +89,7 @@ static int create_strip_zones (mddev_t *mddev)
 	ITERATE_RDEV(mddev, rdev1, tmp1) {
 		int j = rdev1->sb->this_disk.raid_disk;
 
-		if (j < 0 || j >= mddev->sb->raid_disks) {
+		if (j < 0 || j >= mddev->raid_disks) {
 			printk("raid0: bad disk number %d - aborting!\n", j);
 			goto abort;
 		}
@@ -102,9 +102,9 @@ static int create_strip_zones (mddev_t *mddev)
 			smallest = rdev1;
 		cnt++;
 	}
-	if (cnt != mddev->sb->raid_disks) {
+	if (cnt != mddev->raid_disks) {
 		printk("raid0: too few disks (%d of %d) - aborting!\n", cnt, 
-		       mddev->sb->raid_disks);
+		       mddev->raid_disks);
 		goto abort;
 	}
 	zone->nb_dev = cnt;
@@ -271,7 +271,7 @@ static int raid0_make_request (request_queue_t *q, struct bio *bio)
 	mdk_rdev_t *tmp_dev;
 	unsigned long chunk, block, rsect;
 
-	chunk_size = mddev->sb->chunk_size >> 10;
+	chunk_size = mddev->chunk_size >> 10;
 	chunksize_bits = ffz(~chunk_size);
 	block = bio->bi_sector >> 1;
 	hash = conf->hash_table + block / conf->smallest->size;
@@ -360,7 +360,7 @@ static int raid0_status (char *page, mddev_t *mddev)
 				conf->strip_zone[j].size);
 	}
 #endif
-	sz += sprintf(page + sz, " %dk chunks", mddev->sb->chunk_size/1024);
+	sz += sprintf(page + sz, " %dk chunks", mddev->chunk_size/1024);
 	return sz;
 }
 

drivers/md/raid1.c

@@ -1060,7 +1060,7 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
 		if (init_resync(conf))
 			return -ENOMEM;
 
-	max_sector = mddev->sb->size << 1;
+	max_sector = mddev->size << 1;
 	if (sector_nr >= max_sector) {
 		close_sync(conf);
 		return 0;
@@ -1180,14 +1180,13 @@ static int run(mddev_t *mddev)
 	conf_t *conf;
 	int i, j, disk_idx;
 	mirror_info_t *disk;
-	mdp_super_t *sb = mddev->sb;
 	mdk_rdev_t *rdev;
 	struct list_head *tmp;
 
 	MOD_INC_USE_COUNT;
 
-	if (sb->level != 1) {
-		printk(INVALID_LEVEL, mdidx(mddev), sb->level);
+	if (mddev->level != 1) {
+		printk(INVALID_LEVEL, mdidx(mddev), mddev->level);
 		goto out;
 	}
 	/*
@@ -1266,7 +1265,7 @@ static int run(mddev_t *mddev)
 			disk->head_position = 0;
 		}
 	}
-	conf->raid_disks = sb->raid_disks;
+	conf->raid_disks = mddev->raid_disks;
 	conf->mddev = mddev;
 	conf->device_lock = SPIN_LOCK_UNLOCKED;
 
@@ -1316,7 +1315,7 @@ static int run(mddev_t *mddev)
 		}
 	}
 
-	printk(ARRAY_IS_ACTIVE, mdidx(mddev), sb->raid_disks - mddev->degraded, sb->raid_disks);
+	printk(ARRAY_IS_ACTIVE, mdidx(mddev), mddev->raid_disks - mddev->degraded, mddev->raid_disks);
 	/*
 	 * Ok, everything is just fine now
 	 */

drivers/md/raid5.c

@@ -1290,7 +1290,7 @@ static int sync_request (mddev_t *mddev, sector_t sector_nr, int go_faster)
 	int raid_disks = conf->raid_disks;
 	int data_disks = raid_disks-1;
 
-	if (sector_nr >= mddev->sb->size <<1)
+	if (sector_nr >= mddev->size <<1)
 		/* just being told to finish up .. nothing to do */
 		return 0;
 
@@ -1364,15 +1364,14 @@ static int run (mddev_t *mddev)
 {
 	raid5_conf_t *conf;
 	int i, raid_disk, memory;
-	mdp_super_t *sb = mddev->sb;
 	mdk_rdev_t *rdev;
 	struct disk_info *disk;
 	struct list_head *tmp;
 
 	MOD_INC_USE_COUNT;
 
-	if (sb->level != 5 && sb->level != 4) {
-		printk("raid5: md%d: raid level not set to 4/5 (%d)\n", mdidx(mddev), sb->level);
+	if (mddev->level != 5 && mddev->level != 4) {
+		printk("raid5: md%d: raid level not set to 4/5 (%d)\n", mdidx(mddev), mddev->level);
 		MOD_DEC_USE_COUNT;
 		return -EIO;
 	}
@@ -1444,7 +1443,7 @@ static int run (mddev_t *mddev)
 		}
 	}
 
-	for (i = 0; i < sb->raid_disks; i++) {
+	for (i = 0; i < conf->raid_disks; i++) {
 		disk = conf->disks + i;
 
 		if (!disk->used_slot) {
@@ -1457,15 +1456,15 @@ static int run (mddev_t *mddev)
 		}
 	}
 
-	conf->raid_disks = sb->raid_disks;
+	conf->raid_disks = mddev->raid_disks;
 	/*
 	 * 0 for a fully functional array, 1 for a degraded array.
 	 */
 	mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
 	conf->mddev = mddev;
-	conf->chunk_size = sb->chunk_size;
-	conf->level = sb->level;
-	conf->algorithm = sb->layout;
+	conf->chunk_size = mddev->chunk_size;
+	conf->level = mddev->level;
+	conf->algorithm = mddev->layout;
 	conf->max_nr_stripes = NR_STRIPES;
 
 #if 0
@@ -1490,7 +1489,7 @@ static int run (mddev_t *mddev)
 	}
 
 	if (mddev->degraded == 1 &&
-	    !(sb->state & (1<<MD_SB_CLEAN))) {
+	    !(mddev->state & (1<<MD_SB_CLEAN))) {
 		printk(KERN_ERR "raid5: cannot start dirty degraded array for md%d\n", mdidx(mddev));
 		goto abort;
 	}
@@ -1515,10 +1514,12 @@ static int run (mddev_t *mddev)
 	} else
 		printk(KERN_INFO "raid5: allocated %dkB for md%d\n", memory, mdidx(mddev));
 
-	if (conf->working_disks == conf->raid_disks)
-		printk("raid5: raid level %d set md%d active with %d out of %d devices, algorithm %d\n", conf->level, mdidx(mddev), sb->active_disks, sb->raid_disks, conf->algorithm);
+	if (mddev->degraded == 0)
+		printk("raid5: raid level %d set md%d active with %d out of %d devices, algorithm %d\n", conf->level, mdidx(mddev), 
+		       mddev->raid_disks-mddev->degraded, mddev->raid_disks, conf->algorithm);
 	else
-		printk(KERN_ALERT "raid5: raid level %d set md%d active with %d out of %d devices, algorithm %d\n", conf->level, mdidx(mddev), sb->active_disks, sb->raid_disks, conf->algorithm);
+		printk(KERN_ALERT "raid5: raid level %d set md%d active with %d out of %d devices, algorithm %d\n", conf->level, mdidx(mddev),
+		       mddev->raid_disks = mddev->degraded, mddev->raid_disks, conf->algorithm);
 
 	print_raid5_conf(conf);
 
@@ -1590,10 +1591,9 @@ static void printall (raid5_conf_t *conf)
 static int status (char *page, mddev_t *mddev)
 {
 	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
-	mdp_super_t *sb = mddev->sb;
 	int sz = 0, i;
 
-	sz += sprintf (page+sz, " level %d, %dk chunk, algorithm %d", sb->level, sb->chunk_size >> 10, sb->layout);
+	sz += sprintf (page+sz, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
 	sz += sprintf (page+sz, " [%d/%d] [", conf->raid_disks, conf->working_disks);
 	for (i = 0; i < conf->raid_disks; i++)
 		sz += sprintf (page+sz, "%s", conf->disks[i].operational ? "U" : "_");

include/linux/raid/md_k.h

@@ -175,7 +175,20 @@ struct mddev_s
 	int				sb_dirty;
 	int				ro;
 
+	/* Superblock information */
+	int				major_version,
+					minor_version,
+					patch_version;
 	int				persistent;
+	int				chunk_size;
+	time_t				ctime, utime;
+	int				level, layout;
+	int				raid_disks;
+	unsigned long			state;
+	sector_t			size; /* used size of component devices */
+	__u64				events;
+
+	char				uuid[16];
 
 	struct mdk_thread_s		*sync_thread;	/* doing resync or reconstruct */
 	unsigned long			curr_resync;	/* blocks scheduled */