Re: [PATCH/RFC 00/19] Support loop-back NFS mounts

2014-04-16 Thread Dave Chinner
On Thu, Apr 17, 2014 at 11:50:18AM +1000, NeilBrown wrote: > On Thu, 17 Apr 2014 11:27:39 +1000 Dave Chinner wrote: > > > On Thu, Apr 17, 2014 at 10:20:48AM +1000, NeilBrown wrote: > > > A good example is the deadlock with the flush-* threads. > > > flush-* will lock a page, and then call ->writ

Re: [PATCH/RFC 00/19] Support loop-back NFS mounts

2014-04-16 Thread NeilBrown
On Thu, 17 Apr 2014 11:27:39 +1000 Dave Chinner wrote: > On Thu, Apr 17, 2014 at 10:20:48AM +1000, NeilBrown wrote: > > A good example is the deadlock with the flush-* threads. > > flush-* will lock a page, and then call ->writepage. If ->writepage > > allocates memory it can enter reclaim, cal

Re: [PATCH/RFC 00/19] Support loop-back NFS mounts

2014-04-16 Thread Dave Chinner
On Thu, Apr 17, 2014 at 10:20:48AM +1000, NeilBrown wrote: > A good example is the deadlock with the flush-* threads. > flush-* will lock a page, and then call ->writepage. If ->writepage > allocates memory it can enter reclaim, call ->releasepage on NFS, and block > waiting for a COMMIT to compl

Re: [PATCH/RFC 00/19] Support loop-back NFS mounts

2014-04-16 Thread NeilBrown
On Wed, 16 Apr 2014 10:42:07 -0400 Jeff Layton wrote: > On Wed, 16 Apr 2014 14:03:35 +1000 > NeilBrown wrote: > > > Comments, criticisms, etc most welcome. > > > > Thanks, > > NeilBrown > > > > I've only given this a once-over, but the basic concept seems a bit > flawed. IIUC, the basic ide

Re: [PATCH/RFC 00/19] Support loop-back NFS mounts

2014-04-16 Thread Jeff Layton
On Wed, 16 Apr 2014 14:03:35 +1000 NeilBrown wrote: > Loop-back NFS mounts are when the NFS client and server run on the > same host. > > The use-case for this is a high availability cluster with shared > storage. The shared filesystem is mounted on any one machine and > NFS-mounted on the othe