An ULP is supposed to be able to replace a GSS rpc_auth object with
another GSS rpc_auth object using rpcauth_create(). However,
rpcauth_create() in 3.5 reliably fails with -EEXIST in this case.
This is because when gss_create() attempts to create the upcall pipes,
sometimes they are already there. For example if a pipe FS mount
event occurs, or a previous GSS flavor was in use for this rpc_clnt.
The ->pipes_destroy method works only on whatever rpc_auth is
associated with the rpc_clnt when it is destroyed. But there is no
guarantee that this is the same rpc_auth that was created when
the rpc_clnt was created. Thus cached pipe data must be reference
counted and destroyed when no more gss_auth's are using it.
Pipe dentries appear to be created and deleted independently of the
rpc_pipe data. We must allow this to continue in order that mounting
and unmounting the pipe FS can work.
In the meantime, we need to provide a way for gss_create() to find
an existing pipe of a particular name so it may be shared.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Acked-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
---
include/linux/sunrpc/clnt.h | 1
net/sunrpc/auth_gss/auth_gss.c | 141 ++++++++++++++++++++++++++++++++++------
net/sunrpc/clnt.c | 1
3 files changed, 123 insertions(+), 20 deletions(-)
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 523547e..31857e0 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -62,6 +62,7 @@ struct rpc_clnt {
struct rpc_timeout cl_timeout_default;
const struct rpc_program *cl_program;
char *cl_principal; /* target to authenticate to */
+ struct list_head cl_pipes; /* clnt's upcall pipes */
};
/*
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 82a3156..b85ebe8 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -84,6 +84,14 @@ struct gss_auth {
struct rpc_pipe *pipe[2];
};
+struct gss_cached_pipe {
+ struct list_head gp_list;
+ unsigned int gp_ref;
+ char *gp_name;
+ struct rpc_pipe *gp_pipe;
+};
+DEFINE_MUTEX(gss_pipe_mutex);
+
/* pipe_version >= 0 if and only if someone has a pipe open. */
static int pipe_version = -1;
static atomic_t pipe_users = ATOMIC_INIT(0);
@@ -765,6 +773,20 @@ static void gss_pipe_dentry_destroy(struct rpc_pipe *pipe)
}
}
+static void gss_pipe_dentry_destroy_net(struct rpc_clnt *clnt,
+ struct rpc_pipe *pipe)
+{
+ struct net *net = rpc_net_ns(clnt);
+ struct super_block *sb;
+
+ sb = rpc_get_sb_net(net);
+ if (sb) {
+ if (clnt->cl_dentry)
+ gss_pipe_dentry_destroy(pipe);
+ rpc_put_sb_net(net);
+ }
+}
+
/*
* Release existing pipe dentries, but leave the rpc_pipe data
* ready to receive fresh dentries if subsequently needed.
@@ -827,20 +849,6 @@ out_err:
return err;
}
-static void gss_pipes_dentries_destroy_net(struct rpc_clnt *clnt,
- struct rpc_auth *auth)
-{
- struct net *net = rpc_net_ns(clnt);
- struct super_block *sb;
-
- sb = rpc_get_sb_net(net);
- if (sb) {
- if (clnt->cl_dentry)
- gss_pipes_dentries_destroy(auth);
- rpc_put_sb_net(net);
- }
-}
-
static int gss_pipes_dentries_create_net(struct rpc_clnt *clnt,
struct rpc_auth *auth)
{
@@ -857,16 +865,111 @@ static int gss_pipes_dentries_create_net(struct rpc_clnt *clnt,
return err;
}
+static struct gss_cached_pipe *gss_alloc_cached_pipe(char *name)
+{
+ struct gss_cached_pipe *cp;
+
+ cp = kmalloc(sizeof(*cp), GFP_KERNEL);
+ if (cp == NULL)
+ return NULL;
+
+ cp->gp_name = kstrdup(name, GFP_KERNEL);
+ if (cp->gp_name == NULL) {
+ kfree(cp);
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&cp->gp_list);
+ cp->gp_ref = 1;
+ return cp;
+}
+
+static void gss_free_cached_pipe(struct gss_cached_pipe *cp)
+{
+ kfree(cp->gp_name);
+ kfree(cp);
+}
+
+/*
+ * Returns a fresh or cached pipe data object. A cached pipe
+ * data object may already have a dentry attached to it. If an
+ * object cannot be found or created, an ERR_PTR is returned.
+ */
static struct rpc_pipe *gss_mkpipe_data(struct rpc_clnt *clnt,
const struct rpc_pipe_ops *ops,
char *name)
{
- return rpc_mkpipe_data(ops, RPC_PIPE_WAIT_FOR_OPEN);
+ struct gss_cached_pipe *cp;
+ struct rpc_pipe *pipe;
+
+ mutex_lock(&gss_pipe_mutex);
+
+ list_for_each_entry(cp, &clnt->cl_pipes, gp_list) {
+ if (strcmp(cp->gp_name, name) == 0) {
+ dprintk("RPC: %s found '%s' for clnt %p: %p\n",
+ __func__, name, clnt, cp->gp_pipe);
+ cp->gp_ref++;
+ pipe = cp->gp_pipe;
+ goto out;
+ }
+ }
+
+ pipe = ERR_PTR(-ENOMEM);
+ cp = gss_alloc_cached_pipe(name);
+ if (cp == NULL)
+ goto out;
+
+ pipe = rpc_mkpipe_data(ops, RPC_PIPE_WAIT_FOR_OPEN);
+ if (IS_ERR(pipe)) {
+ gss_free_cached_pipe(cp);
+ goto out;
+ }
+
+ dprintk("RPC: %s created '%s' for clnt %p: %p\n",
+ __func__, name, clnt, pipe);
+ cp->gp_pipe = pipe;
+ list_add(&cp->gp_list, &clnt->cl_pipes);
+
+out:
+ mutex_unlock(&gss_pipe_mutex);
+ return pipe;
}
+/*
+ * Decrements a cached pipes reference count, and releases it if
+ * the count goes to zero. Associated dentry is freed if present.
+ */
static void gss_destroy_pipe_data(struct rpc_clnt *clnt, struct rpc_pipe *pipe)
{
- rpc_destroy_pipe_data(pipe);
+ struct gss_cached_pipe *cp;
+
+ mutex_lock(&gss_pipe_mutex);
+
+ list_for_each_entry(cp, &clnt->cl_pipes, gp_list) {
+ if (cp->gp_pipe == pipe)
+ goto found;
+ }
+
+ dprintk("RPC: %s missing cache for pipe %p for clnt %p\n",
+ __func__, pipe, clnt);
+ WARN_ON(true);
+
+ mutex_unlock(&gss_pipe_mutex);
+ return;
+
+found:
+ if (--cp->gp_ref == 0) {
+ dprintk("RPC: %s destroying '%s' (%p) for clnt %p\n",
+ __func__, cp->gp_name, pipe, clnt);
+ gss_pipe_dentry_destroy_net(clnt, pipe);
+ rpc_destroy_pipe_data(pipe);
+ list_del(&cp->gp_list);
+ gss_free_cached_pipe(cp);
+ } else
+ dprintk("RPC: %s leaving '%s' (%p) for clnt %p\n",
+ __func__, cp->gp_name, pipe, clnt);
+
+ mutex_unlock(&gss_pipe_mutex);
}
/*
@@ -925,13 +1028,12 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
err = gss_pipes_dentries_create_net(clnt, auth);
if (err)
goto err_destroy_pipe_0;
+
err = rpcauth_init_credcache(auth);
if (err)
- goto err_unlink_pipes;
+ goto err_destroy_pipe_0;
return auth;
-err_unlink_pipes:
- gss_pipes_dentries_destroy_net(clnt, auth);
err_destroy_pipe_0:
gss_destroy_pipe_data(clnt, gss_auth->pipe[0]);
err_destroy_pipe_1:
@@ -948,7 +1050,6 @@ out_dec:
static void
gss_free(struct gss_auth *gss_auth)
{
- gss_pipes_dentries_destroy_net(gss_auth->client, &gss_auth->rpc_auth);
gss_destroy_pipe_data(gss_auth->client, gss_auth->pipe[0]);
gss_destroy_pipe_data(gss_auth->client, gss_auth->pipe[1]);
gss_mech_put(gss_auth->mech);
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index f56f045..7bf6ed1 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -349,6 +349,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
if (!clnt->cl_principal)
goto out_no_principal;
}
+ INIT_LIST_HEAD(&clnt->cl_pipes);
atomic_set(&clnt->cl_count, 1);
--
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