Messages in this thread | | | Date | Fri, 28 Jun 2013 09:32:23 +0100 | From | Al Viro <> | Subject | Re: frequent softlockups with 3.10rc6. |
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On Thu, Jun 27, 2013 at 10:22:45PM -1000, Linus Torvalds wrote:
> > It looks ok, but I still think it is solving the wrong problem. > > FWIW, your optimisation has much wider application that just this > > one place. I'll have a look to see how we can apply this approach > > across all the inode lookup+validate code we currently have that > > unconditionally takes the inode->i_lock.... > > Yes, I was looking at all the other cases that also seemed to be > testing i_state for those "about to go away" cases.
FWIW, there's a subtle issue here - something like ext2_new_inode() starts with allocating an inode and putting it into list (no I_NEW yet), then decides what inumber will it have and calls insert_inode_locked(), which sets I_NEW. Then we proceed with initializing the inode (and eventually do unlock_new_inode(), which removes I_NEW). We depend on having no pages in the pagecache of that sucker prior to insert_inode_locked() call; you really don't want to start playing with writeback on this half-initialized in-core inode.
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