On Fri, 2023-12-15 at 14:19 +0000, Chuck Lever III wrote: > > On Dec 15, 2023, at 5:59 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > > On Fri, 2023-12-15 at 11:56 +1100, NeilBrown wrote: > > > I sent an earlier version of this series, got some feed back, revised > > > it, but never sent it again. Sorry. > > > > > > The main feedback was around the interaction between sunrpc and nfsd for > > > handling poolstats. I have changed that so that nfsd tells sunrpc where > > > the svc_serv pointer lives, and where to find a mutex to protect it. > > > sunrpc then taks the mutex and accesses the pointer - if not NULL. I > > > think this is nicer than the version that pass around funciton pointers. > > > > > > This series is against nfsd-next > > > > > > Thanks, > > > NeilBrown > > > > > > > > > [PATCH 1/5] nfsd: call nfsd_last_thread() before final nfsd_put() > > > [PATCH 2/5] svc: don't hold reference for poolstats, only mutex. > > > [PATCH 3/5] nfsd: hold nfsd_mutex across entire netlink operation > > > [PATCH 4/5] SUNRPC: discard sv_refcnt, and svc_get/svc_put > > > [PATCH 5/5] nfsd: rename nfsd_last_thread() to nfsd_destroy_serv() > > > > I'm not sure patch #2 is better than the version with function pointers, > > but it seems reasonable. > > > > Note that patch #1 probably needs to go to v6.6 stable, and I think we > > want #3 in v6.7 before it ships. > > Remind me why #3 should go into v6.7-rc ? There's no Fixes tag on > that one. > > It's the problem I noted to Lorenzo the other day: https://lore.kernel.org/linux-nfs/5d9bbb599569ce29f16e4e0eef6b291eda0f375b.camel@xxxxxxxxxx/T/#u Once you've dropped the nfsd_mutex, there is no guarantee that nn->nfsd_serv will still be a valid pointer. Holding the mutex across the operation (like Neil's patch does), should close the race. -- Jeff Layton <jlayton@xxxxxxxxxx>
