bin/113456: gpt does not allow changing partition table

[W.B.Kloke]

>Number:         113456
>Category:       bin
>Synopsis:       gpt does not allow changing partition table
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jun 07 14:50:01 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     W.B.Kloke
>Release:        FreeBSD 6.2-STABLE i386
>Organization:
>Environment:
System: FreeBSD wbk4 6.2-STABLE FreeBSD 6.2-STABLE #10: Sat Jan 20 22:40:43 CET 2007 wb at wbk1:/usr/src/sys/i386/compile/BRIDGE i386


	
>Description:
	GPT partion tables cannot be changed if one of the partions is mounted.

	Example:
	bash-2.05b$ gpt -r show ad1
	      start       size  index  contents
		  0          1         PMBR
		  1          1         Pri GPT header
		  2         32         Pri GPT table
		 34         45         
		 79     317504      1  GPT part - FreeBSD UFS/UFS2
	     317583    1000000      2  GPT part - FreeBSD swap
	    1317583     317520      3  GPT part - FreeBSD UFS/UFS2
	    1635103   37434977      4  GPT part - FreeBSD UFS/UFS2
	   39070080  136729215      5  GPT part - Linux/Windows
	  175799295  214922640         
	  390721935         32         Sec GPT table
	  390721967          1         Sec GPT header

	In my case partition 4 is mounted (the rest of the system resides
	on ad0), and swap space on p2 is active, too.
	The need for GPT partions arises in my case from two cases
	of use:
	1. multimedia data, i.e. big files, which I want to circumvent
		the file system
	2. arenas for (Plan9) venti file system.

>How-To-Repeat:
	Put a UFS file system on one GPT partition and mount it.
	Then the gpt utility even refuses to show the table unless -r
	flag is used.
>Fix:

	Adopt a policy similar to "fdisk -u" or "bsdlabel -e", please.


>Release-Note:
>Audit-Trail:
>Unformatted: