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Commit c21a588f authored by Stanislav Kinsbursky's avatar Stanislav Kinsbursky Committed by Trond Myklebust
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SUNRPC: pipefs per-net operations helper introduced 



During per-net pipes creation and destruction we have to make sure, that pipefs
sb exists for the whole creation/destruction cycle. This is done by using
special mutex which controls pipefs sb reference on network namespace context.
Helper consists of two parts: first of them (rpc_get_dentry_net) searches for
dentry with specified name and returns with mutex taken on success. When pipe
creation or destructions is completed, caller should release this mutex by
rpc_put_dentry_net call.

Signed-off-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 90c4e829

include/linux/sunrpc/rpc_pipe_fs.h

+3 −0
Original line number Diff line number Diff line
@@ -53,6 +53,9 @@ 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 struct super_block *rpc_get_sb_net(const struct net *net);

extern void rpc_put_sb_net(const struct net *net);



extern ssize_t rpc_pipe_generic_upcall(struct file *, struct rpc_pipe_msg *,

				       char __user *, size_t);

net/sunrpc/netns.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ struct sunrpc_net { 
	struct cache_detail *ip_map_cache;



	struct super_block *pipefs_sb;

	struct mutex pipefs_sb_lock;

};



extern int sunrpc_net_id;

net/sunrpc/rpc_pipe.c

+36 −0
Original line number Diff line number Diff line
@@ -1023,6 +1023,40 @@ 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)

{

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



	mutex_init(&sn->pipefs_sb_lock);

}



/*

 * This call will be used for per network namespace operations calls.

 * Note: Function will be returned with pipefs_sb_lock taken if superblock was

 * found. This lock have to be released by rpc_put_sb_net() when all operations

 * will be completed.

 */

struct super_block *rpc_get_sb_net(const struct net *net)

{

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



	mutex_lock(&sn->pipefs_sb_lock);

	if (sn->pipefs_sb)

		return sn->pipefs_sb;

	mutex_unlock(&sn->pipefs_sb_lock);

	return NULL;

}

EXPORT_SYMBOL_GPL(rpc_get_sb_net);



void rpc_put_sb_net(const struct net *net)

{

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



	BUG_ON(sn->pipefs_sb == NULL);

	mutex_unlock(&sn->pipefs_sb_lock);

}

EXPORT_SYMBOL_GPL(rpc_put_sb_net);



static int

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

{
@@ -1077,7 +1111,9 @@ void rpc_kill_sb(struct super_block *sb) 
	struct net *net = sb->s_fs_info;

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



	mutex_lock(&sn->pipefs_sb_lock);

	sn->pipefs_sb = NULL;

	mutex_unlock(&sn->pipefs_sb_lock);

	put_net(net);

	blocking_notifier_call_chain(&rpc_pipefs_notifier_list,

					   RPC_PIPEFS_UMOUNT,

net/sunrpc/sunrpc_syms.c

+1 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ static __net_init int sunrpc_init_net(struct net *net) 
	if (err)

		goto err_ipmap;



	rpc_pipefs_init_net(net);

	return 0;



err_ipmap: