Re: /proc/partitions broken in 2.5.23

[Dave Jones <davej@suse.de>]

On Fri, Jun 21, 2002 at 01:21:40AM +0200, Andries.Brouwer@cwi.nl wrote:

 >     > I got a bug report about an issue with LVM in 2.5.22-dj1, which turns
 >     > out to be caused by broken /proc/partitions in mainline.
 >     > 
 >     > (davej@mesh:davej)$ cat /proc/partitions 
 >     > major minor  #blocks  name
 >     > 
 >     >    8     0          0 sda
 >     >   22     0 1515870810 hdc
 >     > 
 >     > Note the huge numbers in hex are 0x5a5a5a5a, so something
 >     > seems to be getting poisoned somewhere.
 > 
 > Is this LVM?

No.
 
 > I don't see how LVM could produce such values.
 > (And in fact LVM does not even compile, so only a patched LVM
 > could produce anything at all.)

The original person who reported a problem to me used LVM, and 
in the course of discussion, the proc/partitions bug came to light.
The values pasted above are from a box with no LVM compiled.

 > Normally the nr_real field indicates how many devices are
 > present. But LVM sets that to 256 even when nothing is present.
 > So, indeed, when all size fields are set to 0 this would probably
 > yield a list of 256 absent LVM devices.
 > Maybe LVM has to be fixed, or this patch fragment reverted, or both.

As I mentioned in another mail, it seems that removable devices with
no media have no valid #blocks, and is thus getting poisoned.

        Dave

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| Dave Jones.        http://www.codemonkey.org.uk
| SuSE Labs