From 4b9a445e3eeb8bd9278b1ae51c1b3a651e370cd6 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 14 Nov 2013 07:25:17 -0500 Subject: [PATCH] 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: Jeff Layton Signed-off-by: Trond Myklebust --- include/linux/sunrpc/rpc_pipe_fs.h | 3 +- net/sunrpc/netns.h | 1 + net/sunrpc/rpc_pipe.c | 93 +++++++++++++++++++++++++++++- net/sunrpc/sunrpc_syms.c | 8 ++- 4 files changed, 100 insertions(+), 5 deletions(-) diff --git a/include/linux/sunrpc/rpc_pipe_fs.h b/include/linux/sunrpc/rpc_pipe_fs.h index a353e0300b54..85f13424647c 100644 --- a/include/linux/sunrpc/rpc_pipe_fs.h +++ b/include/linux/sunrpc/rpc_pipe_fs.h @@ -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); diff --git a/net/sunrpc/netns.h b/net/sunrpc/netns.h index 779742cfc1ff..8a8e841d1547 100644 --- a/net/sunrpc/netns.h +++ b/net/sunrpc/netns.h @@ -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; diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c index bf04b30a788a..c23458b464c4 100644 --- a/net/sunrpc/rpc_pipe.c +++ b/net/sunrpc/rpc_pipe.c @@ -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); diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c index 3d6498af9adc..cd30120de9e4 100644 --- a/net/sunrpc/sunrpc_syms.c +++ b/net/sunrpc/sunrpc_syms.c @@ -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);