On Fri, Jun 06, 2014 at 09:07:06AM -0400, Jeff Layton wrote: > state_lock is a heavily contended global lock. We don't want to grab > that while simultaneously holding the inode->i_lock. Avoid doing that in > the delegation break callback by ensuring that we add/remove the > dl_perfile under a new per-nfs4_file fi_lock, and hold that while walking > the fi_delegations list. > > We still do need to queue the delegations to the global del_recall_lru > list. Do that in the rpc_prepare op for the delegation recall RPC. It's > possible though that the allocation of the rpc_task will fail, which > would cause the delegation to be leaked. > > If that occurs rpc_release is still called, so we also do it there if > the rpc_task failed to run. This brings up another dilemma -- how do > we know whether it got queued in rpc_prepare or not? > > In order to determine that, we set the dl_time to 0 in the delegation > break callback from the VFS and only set it when we queue it to the > list. If it's still zero by the time we get to rpc_release, then we know > that it never got queued and we can do it then. Compared to this version I have to say the original one that I objected to looks like the lesser evil. I'll take another deeper look at it. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
