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

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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: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-07-06 10:53:21 -04:00
parent 275a5d24bf
commit 6f2e64d3e1
2 changed files with 21 additions and 2 deletions
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1
fs/nfs/nfs4_fs.h
View File

@ -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 */

22
fs/nfs/nfs4state.c
View File

@ -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);