On Mon, Apr 22, 2019 at 12:34:24PM -0400, Jeff Layton wrote: > When a blocked NFS lock is "awoken" we send a callback to the server and > then wake any hosts waiting on it. If a client attempts to get a lock > and then drops off the net, we could end up waiting for a long time > until we end up waking locks blocked on that request. > > Add a new "prepare" phase for CB_NOTIFY_LOCK callbacks, and have it > call locks_delete_block to wake any lock requests waiting on the > one for which we're sending the callback before it is sent. How about this for the wording of that last sentence: So, wake any other waiting lock requests before sending the callback. Do this by calling locks_delete_block in a new "prepare" phase for CB_NOTIFY_LOCK callbacks. Come to think of that, the second sentence is redundant with the code; I think I'll just go with the first. Committing with that. Thanks for working this out, and thanks to Slawomir Pryczek for the reproducer. --b. > > URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363 > Fixes: 16306a61d3b7 ("fs/locks: always delete_block after waiting.") > Reported-by: Slawomir Pryczek <slawek1211@xxxxxxxxx> > Cc: Neil Brown <neilb@xxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > --- > fs/nfsd/nfs4state.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index e87e15df2044..f056b1d3fecd 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -298,6 +298,14 @@ remove_blocked_locks(struct nfs4_lockowner *lo) > } > } > > +static void > +nfsd4_cb_notify_lock_prepare(struct nfsd4_callback *cb) > +{ > + struct nfsd4_blocked_lock *nbl = container_of(cb, > + struct nfsd4_blocked_lock, nbl_cb); > + locks_delete_block(&nbl->nbl_lock); > +} > + > static int > nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task) > { > @@ -325,6 +333,7 @@ nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb) > } > > static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = { > + .prepare = nfsd4_cb_notify_lock_prepare, > .done = nfsd4_cb_notify_lock_done, > .release = nfsd4_cb_notify_lock_release, > }; > -- > 2.20.1
