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Commit 6f2e64d3 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Make the NFS state model work with the nosharedcache mount option 



Consider the case where the user has mounted the remote filesystem
server:/foo on the two local directories /bar and /baz using the
nosharedcache mount option. The files /bar/file and /baz/file are
represented by different inodes in the local namespace, but refer to the
same file /foo/file on the server.
Consider the case where a process opens both /bar/file and /baz/file, then
closes /bar/file: because the nfs4_state is not shared between /bar/file
and /baz/file, the kernel will see that the nfs4_state for /bar/file is no
longer referenced, so it will send off a CLOSE rpc call. Unless the
open_owners differ, then that CLOSE call will invalidate the open state on
/baz/file too.

Conclusion: we cannot share open state owners between two different
non-shared mount instances of the same filesystem.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 275a5d24

fs/nfs/nfs4_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -83,6 +83,7 @@ struct nfs_unique_id { 
struct nfs4_state_owner {

	struct nfs_unique_id so_owner_id;

	struct nfs_client    *so_client;

	struct nfs_server    *so_server;

	struct rb_node	     so_client_node;



	struct rpc_cred	     *so_cred;	 /* Associated cred */

fs/nfs/nfs4state.c

+20 −2
Original line number Diff line number Diff line
@@ -156,8 +156,9 @@ static void nfs_free_unique_id(struct rb_root *root, struct nfs_unique_id *id) 
}



static struct nfs4_state_owner *

nfs4_find_state_owner(struct nfs_client *clp, struct rpc_cred *cred)

nfs4_find_state_owner(struct nfs_server *server, struct rpc_cred *cred)

{

	struct nfs_client *clp = server->nfs_client;

	struct rb_node **p = &clp->cl_state_owners.rb_node,

		       *parent = NULL;

	struct nfs4_state_owner *sp, *res = NULL;
@@ -166,6 +167,14 @@ nfs4_find_state_owner(struct nfs_client *clp, struct rpc_cred *cred) 
		parent = *p;

		sp = rb_entry(parent, struct nfs4_state_owner, so_client_node);



		if (server < sp->so_server) {

			p = &parent->rb_left;

			continue;

		}

		if (server > sp->so_server) {

			p = &parent->rb_right;

			continue;

		}

		if (cred < sp->so_cred)

			p = &parent->rb_left;

		else if (cred > sp->so_cred)
@@ -190,6 +199,14 @@ nfs4_insert_state_owner(struct nfs_client *clp, struct nfs4_state_owner *new) 
		parent = *p;

		sp = rb_entry(parent, struct nfs4_state_owner, so_client_node);



		if (new->so_server < sp->so_server) {

			p = &parent->rb_left;

			continue;

		}

		if (new->so_server > sp->so_server) {

			p = &parent->rb_right;

			continue;

		}

		if (new->so_cred < sp->so_cred)

			p = &parent->rb_left;

		else if (new->so_cred > sp->so_cred)
@@ -260,7 +277,7 @@ struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server, struct 
	struct nfs4_state_owner *sp, *new;



	spin_lock(&clp->cl_lock);

	sp = nfs4_find_state_owner(clp, cred);

	sp = nfs4_find_state_owner(server, cred);

	spin_unlock(&clp->cl_lock);

	if (sp != NULL)

		return sp;
@@ -268,6 +285,7 @@ struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server, struct 
	if (new == NULL)

		return NULL;

	new->so_client = clp;

	new->so_server = server;

	new->so_cred = cred;

	spin_lock(&clp->cl_lock);

	sp = nfs4_insert_state_owner(clp, new);