[RFC v3 5/7] NFS: Propagate NFS_MOUNT_UNSHARED to clients

From: Joshua Watt <jpewhacker@gmail.com>
To: NeilBrown <neilb@suse.com>, Jeff Layton <jlayton@redhat.com>,
	Trond Myklebust <trond.myklebust@primarydata.com>,
	"J . Bruce Fields" <bfields@fieldses.org>
Cc: linux-nfs@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
	David Howells <dhowells@redhat.com>,
	Joshua Watt <JPEWhacker@gmail.com>
Subject: [RFC v3 5/7] NFS: Propagate NFS_MOUNT_UNSHARED to clients
Date: Tue, 14 Nov 2017 17:06:29 -0600	[thread overview]
Message-ID: <20171114230631.14682-6-JPEWhacker@gmail.com> (raw)
In-Reply-To: <20171114230631.14682-1-JPEWhacker@gmail.com>

Propagating the flag allows operations to be performed on the client
without affecting other mounts to the same client, much like operations
on the superblock will not affect other superblocks.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
---
 fs/nfs/client.c           | 9 +++++++--
 fs/nfs/nfs3client.c       | 2 ++
 fs/nfs/nfs4client.c       | 4 ++++
 include/linux/nfs_fs_sb.h | 1 +
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 7bab47d0dd07..9d88dea4bc59 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -328,6 +328,10 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
 		if (clp->cl_cons_state < 0)
 			continue;
 
+		/* Don't match clients that don't want to be shared */
+		if (test_bit(NFS_CS_UNSHARED, &clp->cl_flags))
+			continue;
+
 		/* Different NFS versions cannot share the same nfs_client */
 		if (clp->rpc_ops != data->nfs_mod->rpc_ops)
 			continue;
@@ -428,7 +432,7 @@ init_client(struct nfs_client *new, const struct nfs_client_initdata *cl_init)
  */
 struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
 {
-	struct nfs_client *clp, *new = NULL;
+	struct nfs_client *clp = NULL, *new = NULL;
 	struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
 	const struct nfs_rpc_ops *rpc_ops = cl_init->nfs_mod->rpc_ops;
 
@@ -441,7 +445,8 @@ struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
 	do {
 		spin_lock(&nn->nfs_client_lock);
 
-		clp = nfs_match_client(cl_init);
+		if (!test_bit(NFS_CS_UNSHARED, &cl_init->init_flags))
+			clp = nfs_match_client(cl_init);
 		if (clp) {
 			spin_unlock(&nn->nfs_client_lock);
 			if (new)
diff --git a/fs/nfs/nfs3client.c b/fs/nfs/nfs3client.c
index 7879f2a0fcfd..b62bed41053f 100644
--- a/fs/nfs/nfs3client.c
+++ b/fs/nfs/nfs3client.c
@@ -102,6 +102,8 @@ struct nfs_client *nfs3_set_ds_client(struct nfs_server *mds_srv,
 
 	if (mds_srv->flags & NFS_MOUNT_NORESVPORT)
 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
+	if (mds_srv->flags & NFS_MOUNT_UNSHARED)
+		__set_bit(NFS_CS_UNSHARED, &cl_init.init_flags);
 
 	/* Use the MDS nfs_client cl_ipaddr. */
 	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index ef725106e45c..d4051dda29f0 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -852,6 +852,8 @@ static int nfs4_set_client(struct nfs_server *server,
 		set_bit(NFS_CS_MIGRATION, &cl_init.init_flags);
 	if (test_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status))
 		set_bit(NFS_CS_TSM_POSSIBLE, &cl_init.init_flags);
+	if (server->flags & NFS_MOUNT_UNSHARED)
+		__set_bit(NFS_CS_UNSHARED, &cl_init.init_flags);
 
 	/* Allocate or find a client reference we can use */
 	clp = nfs_get_client(&cl_init);
@@ -910,6 +912,8 @@ struct nfs_client *nfs4_set_ds_client(struct nfs_server *mds_srv,
 
 	if (mds_srv->flags & NFS_MOUNT_NORESVPORT)
 		__set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
+	if (mds_srv->flags & NFS_MOUNT_UNSHARED)
+		__set_bit(NFS_CS_UNSHARED, &cl_init.init_flags);
 
 	/*
 	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 5dac856355f0..0eb7093faea7 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -45,6 +45,7 @@ struct nfs_client {
 #define NFS_CS_INFINITE_SLOTS	3		/* - don't limit TCP slots */
 #define NFS_CS_NO_RETRANS_TIMEOUT	4	/* - Disable retransmit timeouts */
 #define NFS_CS_TSM_POSSIBLE	5		/* - Maybe state migration */
+#define NFS_CS_UNSHARED		6		/* - Client state not shared */
 	struct sockaddr_storage	cl_addr;	/* server identifier */
 	size_t			cl_addrlen;
 	char *			cl_hostname;	/* hostname of server */
-- 
2.13.6

