Merge tag 'nfs-for-6.19-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Bugfixes:
   - Fix 'nlink' attribute update races when unlinking a file
   - Add missing initialisers for the directory verifier in various
     places
   - Don't regress the NFSv4 open state due to misordered racing replies
   - Ensure the NFSv4.x callback server uses the correct transport
     connection
   - Fix potential use-after-free races when shutting down the NFSv4.x
     callback server
   - Fix a pNFS layout commit crash
   - Assorted fixes to ensure correct propagation of mount options when
     the client crosses a filesystem boundary and triggers the VFS
     automount code
   - More localio fixes

  Features and cleanups:
   - Add initial support for basic directory delegations
   - SunRPC back channel code cleanups"

* tag 'nfs-for-6.19-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (24 commits)
  NFSv4: Handle NFS4ERR_NOTSUPP errors for directory delegations
  nfs/localio: remove 61 byte hole from needless ____cacheline_aligned
  nfs/localio: remove alignment size checking in nfs_is_local_dio_possible
  NFS: Fix up the automount fs_context to use the correct cred
  NFS: Fix inheritance of the block sizes when automounting
  NFS: Automounted filesystems should inherit ro,noexec,nodev,sync flags
  Revert "nfs: ignore SB_RDONLY when mounting nfs"
  Revert "nfs: clear SB_RDONLY before getting superblock"
  Revert "nfs: ignore SB_RDONLY when remounting nfs"
  NFS: Add a module option to disable directory delegations
  NFS: Shortcut lookup revalidations if we have a directory delegation
  NFS: Request a directory delegation during RENAME
  NFS: Request a directory delegation on ACCESS, CREATE, and UNLINK
  NFS: Add support for sending GDD_GETATTR
  NFSv4/pNFS: Clear NFS_INO_LAYOUTCOMMIT in pnfs_mark_layout_stateid_invalid
  NFSv4.1: protect destroying and nullifying bc_serv structure
  SUNRPC: new helper function for stopping backchannel server
  SUNRPC: cleanup common code in backchannel request
  NFSv4.1: pass transport for callback shutdown
  NFSv4: ensure the open stateid seqid doesn't go backwards
  ...

2 files changed, 34 insertions, 9 deletions

diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index caa94cf57123..68b1fcdea8f0 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -25,6 +25,22 @@ unsigned int xprt_bc_max_slots(struct rpc_xprt *xprt)
 }
 
 /*
+ * Helper function to nullify backchannel server pointer in transport.
+ * We need to synchronize setting the pointer to NULL (done so after
+ * the backchannel server is shutdown) with the usage of that pointer
+ * by the backchannel request processing routines
+ * xprt_complete_bc_request() and rpcrdma_bc_receive_call().
+ */
+void xprt_svc_destroy_nullify_bc(struct rpc_xprt *xprt, struct svc_serv **serv)
+{
+	spin_lock(&xprt->bc_pa_lock);
+	svc_destroy(serv);
+	xprt->bc_serv = NULL;
+	spin_unlock(&xprt->bc_pa_lock);
+}
+EXPORT_SYMBOL_GPL(xprt_svc_destroy_nullify_bc);
+
+/*
  * Helper routines that track the number of preallocation elements
  * on the transport.
  */
@@ -354,7 +370,6 @@ found:
 void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
 {
 	struct rpc_xprt *xprt = req->rq_xprt;
-	struct svc_serv *bc_serv = xprt->bc_serv;
 
 	spin_lock(&xprt->bc_pa_lock);
 	list_del(&req->rq_bc_pa_list);
@@ -365,7 +380,21 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
 	set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 
 	dprintk("RPC:       add callback request to list\n");
+	xprt_enqueue_bc_request(req);
+}
+
+void xprt_enqueue_bc_request(struct rpc_rqst *req)
+{
+	struct rpc_xprt *xprt = req->rq_xprt;
+	struct svc_serv *bc_serv;
+
 	xprt_get(xprt);
-	lwq_enqueue(&req->rq_bc_list, &bc_serv->sv_cb_list);
-	svc_pool_wake_idle_thread(&bc_serv->sv_pools[0]);
+	spin_lock(&xprt->bc_pa_lock);
+	bc_serv = xprt->bc_serv;
+	if (bc_serv) {
+		lwq_enqueue(&req->rq_bc_list, &bc_serv->sv_cb_list);
+		svc_pool_wake_idle_thread(&bc_serv->sv_pools[0]);
+	}
+	spin_unlock(&xprt->bc_pa_lock);
 }
+EXPORT_SYMBOL_GPL(xprt_enqueue_bc_request);
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index 8c817e755262..2f0f9618dd05 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -9,6 +9,7 @@
 #include <linux/sunrpc/svc.h>
 #include <linux/sunrpc/svc_xprt.h>
 #include <linux/sunrpc/svc_rdma.h>
+#include <linux/sunrpc/bc_xprt.h>
 
 #include "xprt_rdma.h"
 #include <trace/events/rpcrdma.h>
@@ -220,7 +221,6 @@ void rpcrdma_bc_receive_call(struct rpcrdma_xprt *r_xprt,
 			     struct rpcrdma_rep *rep)
 {
 	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
-	struct svc_serv *bc_serv;
 	struct rpcrdma_req *req;
 	struct rpc_rqst *rqst;
 	struct xdr_buf *buf;
@@ -261,11 +261,7 @@ void rpcrdma_bc_receive_call(struct rpcrdma_xprt *r_xprt,
 	trace_xprtrdma_cb_call(r_xprt, rqst);
 
 	/* Queue rqst for ULP's callback service */
-	bc_serv = xprt->bc_serv;
-	xprt_get(xprt);
-	lwq_enqueue(&rqst->rq_bc_list, &bc_serv->sv_cb_list);
-
-	svc_pool_wake_idle_thread(&bc_serv->sv_pools[0]);
+	xprt_enqueue_bc_request(rqst);
 
 	r_xprt->rx_stats.bcall_count++;
 	return;