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Commit 4b9a445e authored by Jeff Layton's avatar Jeff Layton Committed by Trond Myklebust
Browse files

sunrpc: create a new dummy pipe for gssd to hold open 



rpc.gssd will naturally hold open any pipe named */clnt*/gssd that shows
up under rpc_pipefs. That behavior gives us a reliable mechanism to tell
whether it's actually running or not.

Create a new toplevel "gssd" directory in rpc_pipefs when it's mounted.
Under that directory create another directory called "clntXX", and then
within that a pipe called "gssd".

We'll never send an upcall along that pipe, and any downcall written to
it will just return -EINVAL.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent c7848f69

include/linux/sunrpc/rpc_pipe_fs.h

+2 −1
Original line number Diff line number Diff line
@@ -84,7 +84,8 @@ enum { 


extern struct dentry *rpc_d_lookup_sb(const struct super_block *sb,

				      const unsigned char *dir_name);

extern void rpc_pipefs_init_net(struct net *net);

extern int rpc_pipefs_init_net(struct net *net);

extern void rpc_pipefs_exit_net(struct net *net);

extern struct super_block *rpc_get_sb_net(const struct net *net);

extern void rpc_put_sb_net(const struct net *net);

net/sunrpc/netns.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ struct sunrpc_net { 
	struct cache_detail *rsi_cache;



	struct super_block *pipefs_sb;

	struct rpc_pipe *gssd_dummy;

	struct mutex pipefs_sb_lock;



	struct list_head all_clients;

net/sunrpc/rpc_pipe.c

+90 −3
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ 
#define NET_NAME(net)	((net == &init_net) ? " (init_net)" : "")



static struct file_system_type rpc_pipe_fs_type;



static const struct rpc_pipe_ops gssd_dummy_pipe_ops;



static struct kmem_cache *rpc_inode_cachep __read_mostly;
@@ -1159,6 +1159,7 @@ enum { 
	RPCAUTH_nfsd4_cb,

	RPCAUTH_cache,

	RPCAUTH_nfsd,

	RPCAUTH_gssd,

	RPCAUTH_RootEOF

};
@@ -1195,6 +1196,10 @@ static const struct rpc_filelist files[] = { 
		.name = "nfsd",

		.mode = S_IFDIR | S_IRUGO | S_IXUGO,

	},

	[RPCAUTH_gssd] = {

		.name = "gssd",

		.mode = S_IFDIR | S_IRUGO | S_IXUGO,

	},

};



/*
@@ -1208,13 +1213,25 @@ struct dentry *rpc_d_lookup_sb(const struct super_block *sb, 
}

EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);



void rpc_pipefs_init_net(struct net *net)

int rpc_pipefs_init_net(struct net *net)

{

	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);



	sn->gssd_dummy = rpc_mkpipe_data(&gssd_dummy_pipe_ops, 0);

	if (IS_ERR(sn->gssd_dummy))

		return PTR_ERR(sn->gssd_dummy);



	mutex_init(&sn->pipefs_sb_lock);

	sn->gssd_running = 1;

	sn->pipe_version = -1;

	return 0;

}



void rpc_pipefs_exit_net(struct net *net)

{

	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);



	rpc_destroy_pipe_data(sn->gssd_dummy);

}



/*
@@ -1244,11 +1261,73 @@ void rpc_put_sb_net(const struct net *net) 
}

EXPORT_SYMBOL_GPL(rpc_put_sb_net);



static const struct rpc_filelist gssd_dummy_clnt_dir[] = {

	[0] = {

		.name = "clntXX",

		.mode = S_IFDIR | S_IRUGO | S_IXUGO,

	},

};



static ssize_t

dummy_downcall(struct file *filp, const char __user *src, size_t len)

{

	return -EINVAL;

}



static const struct rpc_pipe_ops gssd_dummy_pipe_ops = {

	.upcall		= rpc_pipe_generic_upcall,

	.downcall	= dummy_downcall,

};



/**

 * rpc_gssd_dummy_populate - create a dummy gssd pipe

 * @root:	root of the rpc_pipefs filesystem

 * @pipe_data:	pipe data created when netns is initialized

 *

 * Create a dummy set of directories and a pipe that gssd can hold open to

 * indicate that it is up and running.

 */

static struct dentry *

rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)

{

	int ret = 0;

	struct dentry *gssd_dentry;

	struct dentry *clnt_dentry = NULL;

	struct dentry *pipe_dentry = NULL;

	struct qstr q = QSTR_INIT(files[RPCAUTH_gssd].name,

				  strlen(files[RPCAUTH_gssd].name));



	/* We should never get this far if "gssd" doesn't exist */

	gssd_dentry = d_hash_and_lookup(root, &q);

	if (!gssd_dentry)

		return ERR_PTR(-ENOENT);



	ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);

	if (ret) {

		pipe_dentry = ERR_PTR(ret);

		goto out;

	}



	q.name = gssd_dummy_clnt_dir[0].name;

	q.len = strlen(gssd_dummy_clnt_dir[0].name);

	clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);

	if (!clnt_dentry) {

		pipe_dentry = ERR_PTR(-ENOENT);

		goto out;

	}



	pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data);

out:

	dput(clnt_dentry);

	dput(gssd_dentry);

	return pipe_dentry;

}



static int

rpc_fill_super(struct super_block *sb, void *data, int silent)

{

	struct inode *inode;

	struct dentry *root;

	struct dentry *root, *gssd_dentry;

	struct net *net = data;

	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

	int err;
@@ -1266,6 +1345,13 @@ rpc_fill_super(struct super_block *sb, void *data, int silent) 
		return -ENOMEM;

	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))

		return -ENOMEM;



	gssd_dentry = rpc_gssd_dummy_populate(root, sn->gssd_dummy);

	if (IS_ERR(gssd_dentry)) {

		__rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);

		return PTR_ERR(gssd_dentry);

	}



	dprintk("RPC:       sending pipefs MOUNT notification for net %p%s\n",

		net, NET_NAME(net));

	mutex_lock(&sn->pipefs_sb_lock);
@@ -1280,6 +1366,7 @@ rpc_fill_super(struct super_block *sb, void *data, int silent) 
	return 0;



err_depopulate:

	dput(gssd_dentry);

	blocking_notifier_call_chain(&rpc_pipefs_notifier_list,

					   RPC_PIPEFS_UMOUNT,

					   sb);

net/sunrpc/sunrpc_syms.c

+7 −1
Original line number Diff line number Diff line
@@ -44,12 +44,17 @@ static __net_init int sunrpc_init_net(struct net *net) 
	if (err)

		goto err_unixgid;



	rpc_pipefs_init_net(net);

	err = rpc_pipefs_init_net(net);

	if (err)

		goto err_pipefs;



	INIT_LIST_HEAD(&sn->all_clients);

	spin_lock_init(&sn->rpc_client_lock);

	spin_lock_init(&sn->rpcb_clnt_lock);

	return 0;



err_pipefs:

	unix_gid_cache_destroy(net);

err_unixgid:

	ip_map_cache_destroy(net);

err_ipmap:
@@ -60,6 +65,7 @@ static __net_init int sunrpc_init_net(struct net *net) 


static __net_exit void sunrpc_exit_net(struct net *net)

{

	rpc_pipefs_exit_net(net);

	unix_gid_cache_destroy(net);

	ip_map_cache_destroy(net);

	rpc_proc_exit(net);