[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>

4 files changed, 18 insertions, 6 deletions

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 3d73d94d93a7..ac32a2e8540c 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 8c7af1777819..d964d1f90dec 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 6fa4ff895104..ed5ac83fe83a 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 0a5927c806ca..123f8b46c8ba 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++;
 	}