sunrpc: add debugfs file for displaying client rpc_task queue
It's possible to get a dump of the RPC task queue by writing a value to
/proc/sys/sunrpc/rpc_debug. If you write any value to that file, you get
a dump of the RPC client task list into the log buffer. This is a rather
inconvenient interface however, and makes it hard to get immediate info
about the task queue.
Add a new directory hierarchy under debugfs:
sunrpc/
rpc_clnt/
<clientid>/
Within each clientid directory we create a new "tasks" file that will
dump info similar to what shows up in the log buffer, but with a few
small differences -- we avoid printing raw kernel addresses in favor of
symbolic names and the XID is also displayed.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 70736b9..d86acc6 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -63,6 +63,9 @@
struct rpc_rtt cl_rtt_default;
struct rpc_timeout cl_timeout_default;
const struct rpc_program *cl_program;
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+ struct dentry *cl_debugfs; /* debugfs directory */
+#endif
};
/*
@@ -176,5 +179,6 @@
const char *rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t);
int rpc_localaddr(struct rpc_clnt *, struct sockaddr *, size_t);
+const char *rpc_proc_name(const struct rpc_task *task);
#endif /* __KERNEL__ */
#endif /* _LINUX_SUNRPC_CLNT_H */
diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
index 43f38ee..8353397 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h
@@ -53,9 +53,40 @@
/*
* Sysctl interface for RPC debugging
*/
+
+struct rpc_clnt;
+
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
void rpc_register_sysctl(void);
void rpc_unregister_sysctl(void);
+int sunrpc_debugfs_init(void);
+void sunrpc_debugfs_exit(void);
+int rpc_clnt_debugfs_register(struct rpc_clnt *);
+void rpc_clnt_debugfs_unregister(struct rpc_clnt *);
+#else
+static inline int
+sunrpc_debugfs_init(void)
+{
+ return 0;
+}
+
+static inline void
+sunrpc_debugfs_exit(void)
+{
+ return;
+}
+
+static inline int
+rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
+{
+ return 0;
+}
+
+static inline void
+rpc_clnt_debugfs_unregister(struct rpc_clnt *clnt)
+{
+ return;
+}
#endif
#endif /* _LINUX_SUNRPC_DEBUG_H_ */
diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig
index 0754d0f..fb78117 100644
--- a/net/sunrpc/Kconfig
+++ b/net/sunrpc/Kconfig
@@ -35,6 +35,7 @@
config SUNRPC_DEBUG
bool "RPC: Enable dprintk debugging"
depends on SUNRPC && SYSCTL
+ select DEBUG_FS
help
This option enables a sysctl-based debugging interface
that is be used by the 'rpcdebug' utility to turn on or off
diff --git a/net/sunrpc/Makefile b/net/sunrpc/Makefile
index e5a7a1c..15e6f6c 100644
--- a/net/sunrpc/Makefile
+++ b/net/sunrpc/Makefile
@@ -14,6 +14,7 @@
addr.o rpcb_clnt.o timer.o xdr.o \
sunrpc_syms.o cache.o rpc_pipe.o \
svc_xprt.o
+sunrpc-$(CONFIG_SUNRPC_DEBUG) += debugfs.o
sunrpc-$(CONFIG_SUNRPC_BACKCHANNEL) += backchannel_rqst.o bc_svc.o
sunrpc-$(CONFIG_PROC_FS) += stats.o
sunrpc-$(CONFIG_SYSCTL) += sysctl.o
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 36c64ef..05da12a 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -305,6 +305,10 @@
struct super_block *pipefs_sb;
int err;
+ err = rpc_clnt_debugfs_register(clnt);
+ if (err)
+ return err;
+
pipefs_sb = rpc_get_sb_net(net);
if (pipefs_sb) {
err = rpc_setup_pipedir(pipefs_sb, clnt);
@@ -331,6 +335,7 @@
out:
if (pipefs_sb)
rpc_put_sb_net(net);
+ rpc_clnt_debugfs_unregister(clnt);
return err;
}
@@ -670,6 +675,7 @@
rpc_unregister_client(clnt);
__rpc_clnt_remove_pipedir(clnt);
+ rpc_clnt_debugfs_unregister(clnt);
/*
* A new transport was created. "clnt" therefore
@@ -771,6 +777,7 @@
rcu_dereference(clnt->cl_xprt)->servername);
if (clnt->cl_parent != clnt)
parent = clnt->cl_parent;
+ rpc_clnt_debugfs_unregister(clnt);
rpc_clnt_remove_pipedir(clnt);
rpc_unregister_client(clnt);
rpc_free_iostats(clnt->cl_metrics);
@@ -1397,7 +1404,8 @@
EXPORT_SYMBOL_GPL(rpc_restart_call);
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
-static const char *rpc_proc_name(const struct rpc_task *task)
+const char
+*rpc_proc_name(const struct rpc_task *task)
{
const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c
new file mode 100644
index 0000000..3d77456
--- /dev/null
+++ b/net/sunrpc/debugfs.c
@@ -0,0 +1,191 @@
+/**
+ * debugfs interface for sunrpc
+ *
+ * (c) 2014 Jeff Layton <jlayton@primarydata.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/sunrpc/sched.h>
+#include <linux/sunrpc/clnt.h>
+#include "netns.h"
+
+static struct dentry *topdir;
+static struct dentry *rpc_clnt_dir;
+
+struct rpc_clnt_iter {
+ struct rpc_clnt *clnt;
+ loff_t pos;
+};
+
+static int
+tasks_show(struct seq_file *f, void *v)
+{
+ u32 xid = 0;
+ struct rpc_task *task = v;
+ struct rpc_clnt *clnt = task->tk_client;
+ const char *rpc_waitq = "none";
+
+ if (RPC_IS_QUEUED(task))
+ rpc_waitq = rpc_qname(task->tk_waitqueue);
+
+ if (task->tk_rqstp)
+ xid = be32_to_cpu(task->tk_rqstp->rq_xid);
+
+ seq_printf(f, "%5u %04x %6d 0x%x 0x%x %8ld %ps %sv%u %s a:%ps q:%s\n",
+ task->tk_pid, task->tk_flags, task->tk_status,
+ clnt->cl_clid, xid, task->tk_timeout, task->tk_ops,
+ clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
+ task->tk_action, rpc_waitq);
+ return 0;
+}
+
+static void *
+tasks_start(struct seq_file *f, loff_t *ppos)
+ __acquires(&clnt->cl_lock)
+{
+ struct rpc_clnt_iter *iter = f->private;
+ loff_t pos = *ppos;
+ struct rpc_clnt *clnt = iter->clnt;
+ struct rpc_task *task;
+
+ iter->pos = pos + 1;
+ spin_lock(&clnt->cl_lock);
+ list_for_each_entry(task, &clnt->cl_tasks, tk_task)
+ if (pos-- == 0)
+ return task;
+ return NULL;
+}
+
+static void *
+tasks_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ struct rpc_clnt_iter *iter = f->private;
+ struct rpc_clnt *clnt = iter->clnt;
+ struct rpc_task *task = v;
+ struct list_head *next = task->tk_task.next;
+
+ ++iter->pos;
+ ++*pos;
+
+ /* If there's another task on list, return it */
+ if (next == &clnt->cl_tasks)
+ return NULL;
+ return list_entry(next, struct rpc_task, tk_task);
+}
+
+static void
+tasks_stop(struct seq_file *f, void *v)
+ __releases(&clnt->cl_lock)
+{
+ struct rpc_clnt_iter *iter = f->private;
+ struct rpc_clnt *clnt = iter->clnt;
+
+ spin_unlock(&clnt->cl_lock);
+}
+
+static const struct seq_operations tasks_seq_operations = {
+ .start = tasks_start,
+ .next = tasks_next,
+ .stop = tasks_stop,
+ .show = tasks_show,
+};
+
+static int tasks_open(struct inode *inode, struct file *filp)
+{
+ int ret = seq_open_private(filp, &tasks_seq_operations,
+ sizeof(struct rpc_clnt_iter));
+
+ if (!ret) {
+ struct seq_file *seq = filp->private_data;
+ struct rpc_clnt_iter *iter = seq->private;
+
+ iter->clnt = inode->i_private;
+
+ if (!atomic_inc_not_zero(&iter->clnt->cl_count)) {
+ seq_release_private(inode, filp);
+ ret = -EINVAL;
+ }
+ }
+
+ return ret;
+}
+
+static int
+tasks_release(struct inode *inode, struct file *filp)
+{
+ struct seq_file *seq = filp->private_data;
+ struct rpc_clnt_iter *iter = seq->private;
+
+ rpc_release_client(iter->clnt);
+ return seq_release_private(inode, filp);
+}
+
+static const struct file_operations tasks_fops = {
+ .owner = THIS_MODULE,
+ .open = tasks_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = tasks_release,
+};
+
+int
+rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
+{
+ int len;
+ char name[9]; /* 8 for hex digits + NULL terminator */
+
+ /* Already registered? */
+ if (clnt->cl_debugfs)
+ return 0;
+
+ len = snprintf(name, sizeof(name), "%x", clnt->cl_clid);
+ if (len >= sizeof(name))
+ return -EINVAL;
+
+ /* make the per-client dir */
+ clnt->cl_debugfs = debugfs_create_dir(name, rpc_clnt_dir);
+ if (!clnt->cl_debugfs)
+ return -ENOMEM;
+
+ /* make tasks file */
+ if (!debugfs_create_file("tasks", S_IFREG | S_IRUSR, clnt->cl_debugfs,
+ clnt, &tasks_fops)) {
+ debugfs_remove_recursive(clnt->cl_debugfs);
+ clnt->cl_debugfs = NULL;
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+void
+rpc_clnt_debugfs_unregister(struct rpc_clnt *clnt)
+{
+ debugfs_remove_recursive(clnt->cl_debugfs);
+ clnt->cl_debugfs = NULL;
+}
+
+void __exit
+sunrpc_debugfs_exit(void)
+{
+ debugfs_remove_recursive(topdir);
+}
+
+int __init
+sunrpc_debugfs_init(void)
+{
+ topdir = debugfs_create_dir("sunrpc", NULL);
+ if (!topdir)
+ goto out;
+
+ rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir);
+ if (!rpc_clnt_dir)
+ goto out_remove;
+
+ return 0;
+out_remove:
+ debugfs_remove_recursive(topdir);
+ topdir = NULL;
+out:
+ return -ENOMEM;
+}
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index f632e47..e37fbed 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -97,6 +97,11 @@
err = register_rpc_pipefs();
if (err)
goto out4;
+
+ err = sunrpc_debugfs_init();
+ if (err)
+ goto out5;
+
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
rpc_register_sysctl();
#endif
@@ -104,6 +109,8 @@
init_socket_xprt(); /* clnt sock transport */
return 0;
+out5:
+ unregister_rpc_pipefs();
out4:
unregister_pernet_subsys(&sunrpc_net_ops);
out3:
@@ -120,6 +127,7 @@
rpcauth_remove_module();
cleanup_socket_xprt();
svc_cleanup_xprt_sock();
+ sunrpc_debugfs_exit();
unregister_rpc_pipefs();
rpc_destroy_mempool();
unregister_pernet_subsys(&sunrpc_net_ops);