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| author | Stanislav Kinsbursky <skinsbursky@parallels.com> | 2013-06-24 11:52:38 +0400 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2013-06-28 15:41:18 -0400 |
| commit | 384816051ca9125cd54750e59c780c2a2655fa4f (patch) | |
| tree | b7ef1f57a54d747f750c2ad8c8974b236ff9febf /net/sunrpc/clnt.c | |
| parent | 52fcac988ae6d5a902e9c1d79fc11ba5ec9361e7 (diff) | |
| download | lwn-384816051ca9125cd54750e59c780c2a2655fa4f.tar.gz lwn-384816051ca9125cd54750e59c780c2a2655fa4f.zip | |
SUNRPC: fix races on PipeFS MOUNT notifications
Below are races, when RPC client can be created without PiepFS dentries
CPU#0 CPU#1
----------------------------- -----------------------------
rpc_new_client rpc_fill_super
rpc_setup_pipedir
mutex_lock(&sn->pipefs_sb_lock)
rpc_get_sb_net == NULL
(no per-net PipeFS superblock)
sn->pipefs_sb = sb;
notifier_call_chain(MOUNT)
(client is not in the list)
rpc_register_client
(client without pipes dentries)
To fix this patch:
1) makes PipeFS mount notification call with pipefs_sb_lock being held.
2) releases pipefs_sb_lock on new SUNRPC client creation only after
registration.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc/clnt.c')
| -rw-r--r-- | net/sunrpc/clnt.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 5a750b9c3640..b827a4b91975 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -157,20 +157,15 @@ static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb, } static int -rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name) +rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name, + struct super_block *pipefs_sb) { - struct net *net = rpc_net_ns(clnt); - struct super_block *pipefs_sb; struct dentry *dentry; clnt->cl_dentry = NULL; if (dir_name == NULL) return 0; - pipefs_sb = rpc_get_sb_net(net); - if (!pipefs_sb) - return 0; dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name); - rpc_put_sb_net(net); if (IS_ERR(dentry)) return PTR_ERR(dentry); clnt->cl_dentry = dentry; @@ -296,6 +291,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru struct rpc_clnt *clnt = NULL; struct rpc_auth *auth; int err; + struct super_block *pipefs_sb; /* sanity check the name before trying to print it */ dprintk("RPC: creating %s client for %s (xprt %p)\n", @@ -354,9 +350,12 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru atomic_set(&clnt->cl_count, 1); - err = rpc_setup_pipedir(clnt, program->pipe_dir_name); - if (err < 0) - goto out_no_path; + pipefs_sb = rpc_get_sb_net(rpc_net_ns(clnt)); + if (pipefs_sb) { + err = rpc_setup_pipedir(clnt, program->pipe_dir_name, pipefs_sb); + if (err) + goto out_no_path; + } auth = rpcauth_create(args->authflavor, clnt); if (IS_ERR(auth)) { @@ -369,11 +368,16 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru /* save the nodename */ rpc_clnt_set_nodename(clnt, utsname()->nodename); rpc_register_client(clnt); + if (pipefs_sb) + rpc_put_sb_net(rpc_net_ns(clnt)); return clnt; out_no_auth: - rpc_clnt_remove_pipedir(clnt); + if (pipefs_sb) + __rpc_clnt_remove_pipedir(clnt); out_no_path: + if (pipefs_sb) + rpc_put_sb_net(rpc_net_ns(clnt)); kfree(clnt->cl_principal); out_no_principal: rpc_free_iostats(clnt->cl_metrics); |