On Thu, 2008-07-31 at 20:27 +0100, David Woodhouse wrote: > On Wed, 2008-07-30 at 16:43 -0400, Chris Mason wrote: > > On Wed, 2008-07-30 at 22:13 +0200, Jens Axboe wrote: > > > > [ rcu page cache ] > > > > > > > For btrfs's usage, it should be safe with a simple rcu_read_lock(), if > > > > > the return is referenced safely. > > > > > > > > > > > > > This btrfs code is basically a find_get_page without the get. It should > > > > only be called when I know I already have a reference on the page. > > > > > > Then it's definitely safe ;-) > > > > > > > Yeah, I'm testing on the latest git now and it all seems ok. I'll push > > this out, thanks Sven. > > Seems to crash for me with Linus' current tree. I thought it was > something to do with my fixes for NFS export, but now I've hooked up a > serial console and managed to catch it, I suspect not... > > BUG: unable to handle kernel paging request at ffff880107c2aa00 > IP: [<ffffffffa03e73bc>] end_bio_extent_writepage+0x1f4/0x29c [btrfs] If you can reliably reproduce this, please try with the spin locks instead of rcu read locks. What were you doing at the time? -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
