[PATCH] partitions: let partitions inherit policy from disk

Change the partition code in fs/partitions/check.c to initialize a newly
detected partition's policy field with that of the containing block device
(see patch below).

My reasoning is that function set_disk_ro() in block/genhd.c modifies the
policy field (read-only indicator) of a disk and all contained partitions.
When a partition is detected after the call to set_disk_ro(), the policy
field of this partition will currently not inherit the disk's policy field.
 This behavior poses a problem in cases where a block device can be
'logically de- and reactivated' like e.g.  the s390 DASD driver because
partition detection may run after the policy field has been modified.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Acked-by: Al Viro <viro@ftp.linux.org.uk>
Makes-sense-to: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/partitions/check.c

@@ -339,6 +339,7 @@ void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len)
 	p->start_sect = start;
 	p->nr_sects = len;
 	p->partno = part;
+	p->policy = disk->policy;
 
 	if (isdigit(disk->kobj.name[strlen(disk->kobj.name)-1]))
 		snprintf(p->kobj.name,KOBJ_NAME_LEN,"%sp%d",disk->kobj.name,part);