[PARTITION]: Add whole_disk attribute.

Some partitioning systems create special partitions that
span the entire disk.  One example are Sun partitions, and
this whole-disk partition exists to tell the firmware the
extent of the entire device so it can load the boot block
and do other things.

Such partitions should not be treated as normal partitions,
because all the other partitions overlap this whole-disk one.
So we'd see multiple instances of the same UUID etc. which
we do not want.  udev and friends can thus search for this
'whole_disk' attribute and use it to decide to ignore the
partition.

Signed-off-by: Fabio Massimo Di Nitto <fabbione@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 26 insertions, 8 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index f6962b64660..e3f5eb9882c 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -61,7 +61,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 				}
 			}
 			/* all seems OK */
-			add_partition(disk, part, start, length);
+			add_partition(disk, part, start, length, ADDPART_FLAG_NONE);
 			mutex_unlock(&bdev->bd_mutex);
 			return 0;
 		case BLKPG_DEL_PARTITION:
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 3d73d94d93a..ac32a2e8540 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -365,7 +365,7 @@ void delete_partition(struct gendisk *disk, int part)
 	kobject_put(&p->kobj);
 }
 
-void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len)
+void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len, int flags)
 {
 	struct hd_struct *p;
 
@@ -390,6 +390,15 @@ void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len)
 	if (!disk->part_uevent_suppress)
 		kobject_uevent(&p->kobj, KOBJ_ADD);
 	sysfs_create_link(&p->kobj, &block_subsys.kset.kobj, "subsystem");
+	if (flags & ADDPART_FLAG_WHOLEDISK) {
+		static struct attribute addpartattr = {
+			.name = "whole_disk",
+			.mode = S_IRUSR | S_IRGRP | S_IROTH,
+			.owner = THIS_MODULE,
+		};
+
+		sysfs_create_file(&p->kobj, &addpartattr);
+	}
 	partition_sysfs_add_subdir(p);
 	disk->part[part-1] = p;
 }
@@ -543,9 +552,9 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 			printk(" %s: p%d exceeds device capacity\n",
 				disk->disk_name, p);
 		}
-		add_partition(disk, p, from, size);
+		add_partition(disk, p, from, size, state->parts[p].flags);
 #ifdef CONFIG_BLK_DEV_MD
-		if (state->parts[p].flags)
+		if (state->parts[p].flags & ADDPART_FLAG_RAID)
 			md_autodetect_dev(bdev->bd_dev+p);
 #endif
 	}
diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c
index 8c7af177781..d964d1f90de 100644
--- a/fs/partitions/msdos.c
+++ b/fs/partitions/msdos.c
@@ -155,7 +155,7 @@ parse_extended(struct parsed_partitions *state, struct block_device *bdev,
 
 			put_partition(state, state->next, next, size);
 			if (SYS_IND(p) == LINUX_RAID_PARTITION)
-				state->parts[state->next].flags = 1;
+				state->parts[state->next].flags = ADDPART_FLAG_RAID;
 			loopct = 0;
 			if (++state->next == state->limit)
 				goto done;
diff --git a/fs/partitions/sgi.c b/fs/partitions/sgi.c
index 6fa4ff89510..ed5ac83fe83 100644
--- a/fs/partitions/sgi.c
+++ b/fs/partitions/sgi.c
@@ -72,7 +72,7 @@ int sgi_partition(struct parsed_partitions *state, struct block_device *bdev)
 		if (blocks) {
 			put_partition(state, slot, start, blocks);
 			if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
-				state->parts[slot].flags = 1;
+				state->parts[slot].flags = ADDPART_FLAG_RAID;
 		}
 		slot++;
 	}
diff --git a/fs/partitions/sun.c b/fs/partitions/sun.c
index 0a5927c806c..123f8b46c8b 100644
--- a/fs/partitions/sun.c
+++ b/fs/partitions/sun.c
@@ -80,8 +80,11 @@ int sun_partition(struct parsed_partitions *state, struct block_device *bdev)
 		num_sectors = be32_to_cpu(p->num_sectors);
 		if (num_sectors) {
 			put_partition(state, slot, st_sector, num_sectors);
+			state->parts[slot].flags = 0;
 			if (label->infos[i].id == LINUX_RAID_PARTITION)
-				state->parts[slot].flags = 1;
+				state->parts[slot].flags |= ADDPART_FLAG_RAID;
+			if (label->infos[i].id == SUN_WHOLE_DISK)
+				state->parts[slot].flags |= ADDPART_FLAG_WHOLEDISK;
 		}
 		slot++;
 	}
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 0a022b2f63f..247734f7881 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -20,6 +20,8 @@ enum {
 	LINUX_EXTENDED_PARTITION = 0x85,
 	WIN98_EXTENDED_PARTITION = 0x0f,
 
+	SUN_WHOLE_DISK = DOS_EXTENDED_PARTITION,
+
 	LINUX_SWAP_PARTITION = 0x82,
 	LINUX_RAID_PARTITION = 0xfd,	/* autodetect RAID partition */
 
@@ -400,10 +402,14 @@ struct unixware_disklabel {
 
 #ifdef __KERNEL__
 
+#define ADDPART_FLAG_NONE	0
+#define ADDPART_FLAG_RAID	1
+#define ADDPART_FLAG_WHOLEDISK	2
+
 char *disk_name (struct gendisk *hd, int part, char *buf);
 
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
-extern void add_partition(struct gendisk *, int, sector_t, sector_t);
+extern void add_partition(struct gendisk *, int, sector_t, sector_t, int);
 extern void delete_partition(struct gendisk *, int);
 
 extern struct gendisk *alloc_disk_node(int minors, int node_id);