[B.A.T.M.A.N.] [PATCH 4/4] batman-adv: debugfs: Add netns support

Andrew Lunn
2016-01-20T17:48:30Z

Unlike sysfs, debugfs is not netns aware. So batman has to take care
to avoid namespace clashes.

Each namespace is given a directory within debugfs/batman-adv/netns,
using the namespaces inum as the directory name.

Files for namespaces other than the global namespace are placed within
the namespace specific directory. Additionally, a symbolic link is
used to link the global namespaces inum back to debugfs/batman-adv/ so
tools do not need to differentiate between the global namespace and
other namespaces.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
net/batman-adv/debugfs.c | 118 +++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 115 insertions(+), 3 deletions(-)

diff --git a/net/batman-adv/debugfs.c b/net/batman-adv/debugfs.c
index c4c1e80..b87ffad 100644
--- a/net/batman-adv/debugfs.c
+++ b/net/batman-adv/debugfs.c
@@ -53,6 +53,73 @@
#include "translation-table.h"

static struct dentry *batadv_debugfs;
+static struct dentry *batadv_ns_debugfs;
+
+struct batadv_debugfs_ns_entry {
+ struct net *net;
+ struct dentry *dir;
+ struct kref refcount;
+ struct list_head link;
+};
+
+static LIST_HEAD(batadv_debugfs_ns);
+static DEFINE_MUTEX(batadv_debugfs_ns_mutex);
+
+static struct dentry *batadv_debugfs_ns_get(struct net *net)
+{
+ struct batadv_debugfs_ns_entry *ns_entry;
+ char name[32];
+
+ mutex_lock(&batadv_debugfs_ns_mutex);
+ list_for_each_entry(ns_entry, &batadv_debugfs_ns, link) {
+ if (ns_entry->net == net) {
+ kref_get(&ns_entry->refcount);
+ mutex_unlock(&batadv_debugfs_ns_mutex);
+ return ns_entry->dir;
+ }
+ }
+
+ ns_entry = kzalloc(sizeof(*ns_entry), GFP_ATOMIC);
+ if (ns_entry) {
+ INIT_LIST_HEAD(&ns_entry->link);
+ ns_entry->net = net;
+ kref_init(&ns_entry->refcount);
+ sprintf(name, "%u", net->ns.inum);
+ ns_entry->dir = debugfs_create_dir(name, batadv_ns_debugfs);
+ if (!ns_entry->dir) {
+ kfree(ns_entry);
+ mutex_unlock(&batadv_debugfs_ns_mutex);
+ return NULL;
+ }
+ list_add(&ns_entry->link, &batadv_debugfs_ns);
+ }
+ mutex_unlock(&batadv_debugfs_ns_mutex);
+ return ns_entry->dir;
+}
+
+static void batadv_ns_entry_release(struct kref *ref)
+{
+ struct batadv_debugfs_ns_entry *ns_entry;
+
+ ns_entry = container_of(ref, struct batadv_debugfs_ns_entry, refcount);
+ debugfs_remove_recursive(ns_entry->dir);
+ list_del(&ns_entry->link);
+ kfree(ns_entry);
+}
+
+static void batadv_debugfs_ns_put(struct net *net)
+{
+ struct batadv_debugfs_ns_entry *ns_entry;
+
+ mutex_lock(&batadv_debugfs_ns_mutex);
+ list_for_each_entry(ns_entry, &batadv_debugfs_ns, link) {
+ if (ns_entry->net == net) {
+ kref_put(&ns_entry->refcount, batadv_ns_entry_release);
+ break;
+ }
+ }
+ mutex_unlock(&batadv_debugfs_ns_mutex);
+}

#ifdef CONFIG_BATMAN_ADV_DEBUG
#define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1)
@@ -438,6 +505,7 @@ void batadv_debugfs_init(void)
{
struct batadv_debuginfo **bat_debug;
struct dentry *file;
+ char name[32];

batadv_debugfs = debugfs_create_dir(BATADV_DEBUGFS_SUBDIR, NULL);
if (batadv_debugfs == ERR_PTR(-ENODEV))
@@ -458,6 +526,15 @@ void batadv_debugfs_init(void)
}
}

+ batadv_ns_debugfs = debugfs_create_dir("netns", batadv_debugfs);
+ if (!batadv_ns_debugfs)
+ goto err;
+
+ /* Create a symlink for the default name space */
+ sprintf(name, "%u", init_net.ns.inum);
+ if (!debugfs_create_symlink(name, batadv_ns_debugfs, ".."))
+ goto err;
+
return;
err:
debugfs_remove_recursive(batadv_debugfs);
@@ -477,14 +554,26 @@ void batadv_debugfs_destroy(void)
*/
int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
{
+ char *name = hard_iface->net_dev->name;
+ struct net *net = dev_net(hard_iface->net_dev);
struct batadv_debuginfo **bat_debug;
+ struct dentry *debugfs_ns_dir;
struct dentry *file;

if (!batadv_debugfs)
goto out;

- hard_iface->debug_dir = debugfs_create_dir(hard_iface->net_dev->name,
- batadv_debugfs);
+ if (net != &init_net) {
+ debugfs_ns_dir = batadv_debugfs_ns_get(net);
+ if (!debugfs_ns_dir)
+ goto out;
+ hard_iface->debug_dir = debugfs_create_dir(name,
+ debugfs_ns_dir);
+ } else {
+ hard_iface->debug_dir = debugfs_create_dir(name,
+ batadv_debugfs);
+ }
+
if (!hard_iface->debug_dir)
goto out;

@@ -502,6 +591,8 @@ int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
rem_attr:
debugfs_remove_recursive(hard_iface->debug_dir);
hard_iface->debug_dir = NULL;
+ if (net != &init_net)
+ batadv_debugfs_ns_put(net);
out:
return -ENOMEM;
}
@@ -513,22 +604,38 @@ out:
*/
void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface)
{
+ struct net *net = dev_net(hard_iface->net_dev);
+
if (batadv_debugfs) {
debugfs_remove_recursive(hard_iface->debug_dir);
hard_iface->debug_dir = NULL;
}
+ if (net != &init_net)
+ batadv_debugfs_ns_put(net);
}

int batadv_debugfs_add_meshif(struct net_device *dev)
{
struct batadv_priv *bat_priv = netdev_priv(dev);
struct batadv_debuginfo **bat_debug;
+ struct net *net = dev_net(dev);
+ struct dentry *debugfs_ns_dir;
struct dentry *file;

if (!batadv_debugfs)
goto out;

- bat_priv->debug_dir = debugfs_create_dir(dev->name, batadv_debugfs);
+ if (net != &init_net) {
+ debugfs_ns_dir = batadv_debugfs_ns_get(net);
+ if (!debugfs_ns_dir)
+ goto out;
+ bat_priv->debug_dir = debugfs_create_dir(dev->name,
+ debugfs_ns_dir);
+ } else {
+ bat_priv->debug_dir = debugfs_create_dir(dev->name,
+ batadv_debugfs);
+ }
+
if (!bat_priv->debug_dir)
goto out;

@@ -557,6 +664,8 @@ int batadv_debugfs_add_meshif(struct net_device *dev)
rem_attr:
debugfs_remove_recursive(bat_priv->debug_dir);
bat_priv->debug_dir = NULL;
+ if (net != &init_net)
+ batadv_debugfs_ns_put(net);
out:
return -ENOMEM;
}
@@ -564,6 +673,7 @@ out:
void batadv_debugfs_del_meshif(struct net_device *dev)
{
struct batadv_priv *bat_priv = netdev_priv(dev);
+ struct net *net = dev_net(dev);

batadv_debug_log_cleanup(bat_priv);

@@ -571,4 +681,6 @@ void batadv_debugfs_del_meshif(struct net_device *dev)
debugfs_remove_recursive(bat_priv->debug_dir);
bat_priv->debug_dir = NULL;
}
+ if (net != &init_net)
+ batadv_debugfs_ns_put(net);
}
--
2.7.0.rc3