"Stephen C. Tweedie" wrote:
> 
> Hi,
> 
> On Wed, 12 May 1999 12:30:27 +0200, "Manfred Spraul"
> <masp0008@stud.uni-sb.de> said:
> 
> > There is another problem with this line:
> > set_blocksize() also means that the previous block size
> > doesn't work anymore:
> > if you accidentially enter 'swapon /dev/hda1' (my root drive)
> > instead of 'swapon /dev/hda3', then you have to fsck:
> 
> Yep, it would make perfect sense to move the set_blocksize to be after
> the EBUSY check.

Unfortunately that doesn't solve the problem:
The current EBUSY check checks that the partition is not used as a
swap partition, it doesn't check the VFS, and it doesn't check
whether the RAID driver uses the volume.

I've attached an old patch (vs.2.2.6):
I've send that patch to linux-kernel@vger, Alan (..wait until Linus
returns from vacation..), Linus (no reply).

The patch adds a bitmap to the block cache for EBUSY checks.
Actually, we can use this bitmap for other bits if we use devfs and
dynamic MAJOR/MINOR codes:
we must replace all 'MAJOR==LOOP', 'MAJOR==IDE' etc. if we want to
support dynamic block device MAJOR/MINOR's.

Additionally, we save 6-8 kB kernel memory. (ro_bits was an 8 kB
static array).

If you think that the patch is usefull, then I'll make a new patch
vs 2.3.0, otherwise I'll wait until devfs is added, and I'll
try to write a larger patch (dynamic MAJOR/MINOR for block cache)
that includes this one.

--
	Manfred