nfsd: Avoid taking state_lock while holding inode lock in nfsd_break_one_deleg

state_lock is a heavily contended global lock. We don't want to grab
that while simultaneously holding the inode->i_lock.

Add a new per-nfs4_file lock that we can use to protect the
per-nfs4_file delegation list. Hold that while walking the list in the
break_deleg callback and queue the workqueue job for each one.

The workqueue job can then take the state_lock and do the list
manipulations without the i_lock being held prior to starting the
rpc call.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 21 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 30a71cb46001..a88a93e09d69 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -933,7 +933,7 @@ void nfsd4_shutdown_callback(struct nfs4_client *clp)
 	set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
 	/*
 	 * Note this won't actually result in a null callback;
-	 * instead, nfsd4_do_callback_rpc() will detect the killed
+	 * instead, nfsd4_run_cb_null() will detect the killed
 	 * client, destroy the rpc client, and stop:
 	 */
 	do_probe_callback(clp);
@@ -1011,10 +1011,9 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 		run_nfsd4_cb(cb);
 }
 
-void
-nfsd4_do_callback_rpc(struct work_struct *w)
+static void
+nfsd4_run_callback_rpc(struct nfsd4_callback *cb)
 {
-	struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
 	struct nfs4_client *clp = cb->cb_clp;
 	struct rpc_clnt *clnt;
 
@@ -1032,6 +1031,24 @@ nfsd4_do_callback_rpc(struct work_struct *w)
 			cb->cb_ops, cb);
 }
 
+void
+nfsd4_run_cb_null(struct work_struct *w)
+{
+	struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback,
+							cb_work);
+	nfsd4_run_callback_rpc(cb);
+}
+
+void
+nfsd4_run_cb_recall(struct work_struct *w)
+{
+	struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback,
+							cb_work);
+
+	nfsd4_prepare_cb_recall(cb->cb_op);
+	nfsd4_run_callback_rpc(cb);
+}
+
 void nfsd4_cb_recall(struct nfs4_delegation *dp)
 {
 	struct nfsd4_callback *cb = &dp->dl_recall;