lkml.org 
[lkml]   [2010]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Bugs in mkfs.xfs, device mapper, xfs, and /dev/ram
On Sat, Dec 04, 2010 at 04:11:40AM +1100, Nick Piggin wrote:
> > Alternatively, what about switching brd away from overloading BLKFLSBUF
> > to a real implementation of (overloaded) BLKDISCARD support in brd.c?
> > One that doesn't blindly nuke the entire device but that properly
> > processes the discard request.
>
> Yeah the situation really sucks (mkfs.jfs doesn't work on ramdisk
> for the same reason).
>
> I want to unfortunately keep ioctl for compatibility, but adding new
> saner ones would be welcome. Also, having a non-default config or
> load time parameter for brd, to skip the special case, if that would
> help testing on older userspace.

How many programs actually depend on BLKFLSBUF dropping the pages used
in /dev/ram? The fact that it did this at all was a historical
accident of how the original /dev/ram was implemented (in the buffer
cache directly), and not anything that was intended. I think that's
something that we should be able to fix, since the number of programs
that knowly operate on the ramdisk is quite small. Just a few system
programs used by distributions in their early boot scripts....

So I would argue for dropping the "special" behavior of BLKFLSBUF for
/dev/ram.

- Ted


\
 
 \ /
  Last update: 2010-12-03 19:17    [W:0.079 / U:1.608 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site