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authorJeff Layton <jlayton@poochiereds.net>2015-03-31 12:03:28 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-04-23 14:42:27 -0400
commit3f9400981691f6845e5c22b962500742b80a5484 (patch)
tree5f9aacd13929b2e38067e8c34feb529a91696540 /net
parent5d05e54af3cdbb13cf19c557ff2184781b91a22c (diff)
downloadkernel-3f9400981691f6845e5c22b962500742b80a5484.tar.gz
sunrpc: make debugfs file creation failure non-fatal
v2: gracefully handle the case where some dentry pointers end up NULL and be more dilligent about zeroing out dentry pointers We currently have a problem that SELinux policy is being enforced when creating debugfs files. If a debugfs file is created as a side effect of doing some syscall, then that creation can fail if the SELinux policy for that process prevents it. This seems wrong. We don't do that for files under /proc, for instance, so Bruce has proposed a patch to fix that. While discussing that patch however, Greg K.H. stated: "No kernel code should care / fail if a debugfs function fails, so please fix up the sunrpc code first." This patch converts all of the sunrpc debugfs setup code to be void return functins, and the callers to not look for errors from those functions. This should allow rpc_clnt and rpc_xprt creation to work, even if the kernel fails to create debugfs files for some reason. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/clnt.c4
-rw-r--r--net/sunrpc/debugfs.c52
-rw-r--r--net/sunrpc/sunrpc_syms.c7
-rw-r--r--net/sunrpc/xprt.c7
4 files changed, 32 insertions, 38 deletions
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 612aa73bbc60..e6ce1517367f 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -303,9 +303,7 @@ static int rpc_client_register(struct rpc_clnt *clnt,
struct super_block *pipefs_sb;
int err;
- err = rpc_clnt_debugfs_register(clnt);
- if (err)
- return err;
+ rpc_clnt_debugfs_register(clnt);
pipefs_sb = rpc_get_sb_net(net);
if (pipefs_sb) {
diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c
index e811f390f9f6..82962f7e6e88 100644
--- a/net/sunrpc/debugfs.c
+++ b/net/sunrpc/debugfs.c
@@ -129,48 +129,52 @@ static const struct file_operations tasks_fops = {
.release = tasks_release,
};
-int
+void
rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
{
- int len, err;
+ int len;
char name[24]; /* enough for "../../rpc_xprt/ + 8 hex digits + NULL */
+ struct rpc_xprt *xprt;
/* Already registered? */
- if (clnt->cl_debugfs)
- return 0;
+ if (clnt->cl_debugfs || !rpc_clnt_dir)
+ return;
len = snprintf(name, sizeof(name), "%x", clnt->cl_clid);
if (len >= sizeof(name))
- return -EINVAL;
+ return;
/* make the per-client dir */
clnt->cl_debugfs = debugfs_create_dir(name, rpc_clnt_dir);
if (!clnt->cl_debugfs)
- return -ENOMEM;
+ return;
/* make tasks file */
- err = -ENOMEM;
if (!debugfs_create_file("tasks", S_IFREG | S_IRUSR, clnt->cl_debugfs,
clnt, &tasks_fops))
goto out_err;
- err = -EINVAL;
rcu_read_lock();
+ xprt = rcu_dereference(clnt->cl_xprt);
+ /* no "debugfs" dentry? Don't bother with the symlink. */
+ if (!xprt->debugfs) {
+ rcu_read_unlock();
+ return;
+ }
len = snprintf(name, sizeof(name), "../../rpc_xprt/%s",
- rcu_dereference(clnt->cl_xprt)->debugfs->d_name.name);
+ xprt->debugfs->d_name.name);
rcu_read_unlock();
+
if (len >= sizeof(name))
goto out_err;
- err = -ENOMEM;
if (!debugfs_create_symlink("xprt", clnt->cl_debugfs, name))
goto out_err;
- return 0;
+ return;
out_err:
debugfs_remove_recursive(clnt->cl_debugfs);
clnt->cl_debugfs = NULL;
- return err;
}
void
@@ -226,33 +230,33 @@ static const struct file_operations xprt_info_fops = {
.release = xprt_info_release,
};
-int
+void
rpc_xprt_debugfs_register(struct rpc_xprt *xprt)
{
int len, id;
static atomic_t cur_id;
char name[9]; /* 8 hex digits + NULL term */
+ if (!rpc_xprt_dir)
+ return;
+
id = (unsigned int)atomic_inc_return(&cur_id);
len = snprintf(name, sizeof(name), "%x", id);
if (len >= sizeof(name))
- return -EINVAL;
+ return;
/* make the per-client dir */
xprt->debugfs = debugfs_create_dir(name, rpc_xprt_dir);
if (!xprt->debugfs)
- return -ENOMEM;
+ return;
/* make tasks file */
if (!debugfs_create_file("info", S_IFREG | S_IRUSR, xprt->debugfs,
xprt, &xprt_info_fops)) {
debugfs_remove_recursive(xprt->debugfs);
xprt->debugfs = NULL;
- return -ENOMEM;
}
-
- return 0;
}
void
@@ -266,14 +270,17 @@ void __exit
sunrpc_debugfs_exit(void)
{
debugfs_remove_recursive(topdir);
+ topdir = NULL;
+ rpc_clnt_dir = NULL;
+ rpc_xprt_dir = NULL;
}
-int __init
+void __init
sunrpc_debugfs_init(void)
{
topdir = debugfs_create_dir("sunrpc", NULL);
if (!topdir)
- goto out;
+ return;
rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir);
if (!rpc_clnt_dir)
@@ -283,10 +290,9 @@ sunrpc_debugfs_init(void)
if (!rpc_xprt_dir)
goto out_remove;
- return 0;
+ return;
out_remove:
debugfs_remove_recursive(topdir);
topdir = NULL;
-out:
- return -ENOMEM;
+ rpc_clnt_dir = NULL;
}
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index e37fbed87956..ee5d3d253102 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -98,10 +98,7 @@ init_sunrpc(void)
if (err)
goto out4;
- err = sunrpc_debugfs_init();
- if (err)
- goto out5;
-
+ sunrpc_debugfs_init();
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
rpc_register_sysctl();
#endif
@@ -109,8 +106,6 @@ init_sunrpc(void)
init_socket_xprt(); /* clnt sock transport */
return 0;
-out5:
- unregister_rpc_pipefs();
out4:
unregister_pernet_subsys(&sunrpc_net_ops);
out3:
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index e3015aede0d9..9949722d99ce 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1331,7 +1331,6 @@ static void xprt_init(struct rpc_xprt *xprt, struct net *net)
*/
struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
{
- int err;
struct rpc_xprt *xprt;
struct xprt_class *t;
@@ -1372,11 +1371,7 @@ found:
return ERR_PTR(-ENOMEM);
}
- err = rpc_xprt_debugfs_register(xprt);
- if (err) {
- xprt_destroy(xprt);
- return ERR_PTR(err);
- }
+ rpc_xprt_debugfs_register(xprt);
dprintk("RPC: created transport %p with %u slots\n", xprt,
xprt->max_reqs);