1 files changed, 88 insertions, 99 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 62c6506d663f..bcfa2add6dda 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -20,6 +20,7 @@
 #include <linux/notifier.h>
 #include <linux/irqflags.h>
 #include <linux/debugfs.h>
+#include <linux/tracefs.h>
 #include <linux/pagemap.h>
 #include <linux/hardirq.h>
 #include <linux/linkage.h>
@@ -31,6 +32,7 @@
 #include <linux/splice.h>
 #include <linux/kdebug.h>
 #include <linux/string.h>
+#include <linux/mount.h>
 #include <linux/rwsem.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
@@ -4105,9 +4107,24 @@ static void tracing_set_nop(struct trace_array *tr)
 	tr->current_trace = &nop_trace;
 }
 
-static int tracing_set_tracer(struct trace_array *tr, const char *buf)
+static void update_tracer_options(struct trace_array *tr, struct tracer *t)
 {
 	static struct trace_option_dentry *topts;
+
+	/* Only enable if the directory has been created already. */
+	if (!tr->dir)
+		return;
+
+	/* Currently, only the top instance has options */
+	if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL))
+		return;
+
+	destroy_trace_option_files(topts);
+	topts = create_trace_option_files(tr, t);
+}
+
+static int tracing_set_tracer(struct trace_array *tr, const char *buf)
+{
 	struct tracer *t;
 #ifdef CONFIG_TRACER_MAX_TRACE
 	bool had_max_tr;
@@ -4172,11 +4189,7 @@ static int tracing_set_tracer(struct trace_array *tr, const char *buf)
 		free_snapshot(tr);
 	}
 #endif
-	/* Currently, only the top instance has options */
-	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
-		destroy_trace_option_files(topts);
-		topts = create_trace_option_files(tr, t);
-	}
+	update_tracer_options(tr, t);
 
 #ifdef CONFIG_TRACER_MAX_TRACE
 	if (t->use_max_tr && !had_max_tr) {
@@ -5817,6 +5830,14 @@ static inline __init int register_snapshot_cmd(void) { return 0; }
 
 static struct dentry *tracing_get_dentry(struct trace_array *tr)
 {
+	if (WARN_ON(!tr->dir))
+		return ERR_PTR(-ENODEV);
+
+	/* Top directory uses NULL as the parent */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return NULL;
+
+	/* All sub buffers have a descriptor */
 	return tr->dir;
 }
 
@@ -5831,10 +5852,10 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 	if (IS_ERR(d_tracer))
 		return NULL;
 
-	tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
+	tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
 
 	WARN_ONCE(!tr->percpu_dir,
-		  "Could not create debugfs directory 'per_cpu/%d'\n", cpu);
+		  "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
 
 	return tr->percpu_dir;
 }
@@ -5851,7 +5872,7 @@ trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
 }
 
 static void
-tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
+tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
 {
 	struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
 	struct dentry *d_cpu;
@@ -5861,9 +5882,9 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
 		return;
 
 	snprintf(cpu_dir, 30, "cpu%ld", cpu);
-	d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
+	d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
 	if (!d_cpu) {
-		pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
+		pr_warning("Could not create tracefs '%s' entry\n", cpu_dir);
 		return;
 	}
 
@@ -6015,9 +6036,9 @@ struct dentry *trace_create_file(const char *name,
 {
 	struct dentry *ret;
 
-	ret = debugfs_create_file(name, mode, parent, data, fops);
+	ret = tracefs_create_file(name, mode, parent, data, fops);
 	if (!ret)
-		pr_warning("Could not create debugfs '%s' entry\n", name);
+		pr_warning("Could not create tracefs '%s' entry\n", name);
 
 	return ret;
 }
@@ -6034,9 +6055,9 @@ static struct dentry *trace_options_init_dentry(struct trace_array *tr)
 	if (IS_ERR(d_tracer))
 		return NULL;
 
-	tr->options = debugfs_create_dir("options", d_tracer);
+	tr->options = tracefs_create_dir("options", d_tracer);
 	if (!tr->options) {
-		pr_warning("Could not create debugfs directory 'options'\n");
+		pr_warning("Could not create tracefs directory 'options'\n");
 		return NULL;
 	}
 
@@ -6105,7 +6126,7 @@ destroy_trace_option_files(struct trace_option_dentry *topts)
 		return;
 
 	for (cnt = 0; topts[cnt].opt; cnt++)
-		debugfs_remove(topts[cnt].entry);
+		tracefs_remove(topts[cnt].entry);
 
 	kfree(topts);
 }
@@ -6194,7 +6215,7 @@ static const struct file_operations rb_simple_fops = {
 struct dentry *trace_instance_dir;
 
 static void
-init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
+init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
 
 static int
 allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
@@ -6271,7 +6292,7 @@ static void free_trace_buffers(struct trace_array *tr)
 #endif
 }
 
-static int new_instance_create(const char *name)
+static int instance_mkdir(const char *name)
 {
 	struct trace_array *tr;
 	int ret;
@@ -6310,17 +6331,17 @@ static int new_instance_create(const char *name)
 	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
 		goto out_free_tr;
 
-	tr->dir = debugfs_create_dir(name, trace_instance_dir);
+	tr->dir = tracefs_create_dir(name, trace_instance_dir);
 	if (!tr->dir)
 		goto out_free_tr;
 
 	ret = event_trace_add_tracer(tr->dir, tr);
 	if (ret) {
-		debugfs_remove_recursive(tr->dir);
+		tracefs_remove_recursive(tr->dir);
 		goto out_free_tr;
 	}
 
-	init_tracer_debugfs(tr, tr->dir);
+	init_tracer_tracefs(tr, tr->dir);
 
 	list_add(&tr->list, &ftrace_trace_arrays);
 
@@ -6341,7 +6362,7 @@ static int new_instance_create(const char *name)
 
 }
 
-static int instance_delete(const char *name)
+static int instance_rmdir(const char *name)
 {
 	struct trace_array *tr;
 	int found = 0;
@@ -6382,82 +6403,17 @@ static int instance_delete(const char *name)
 	return ret;
 }
 
-static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t mode)
-{
-	struct dentry *parent;
-	int ret;
-
-	/* Paranoid: Make sure the parent is the "instances" directory */
-	parent = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
-	if (WARN_ON_ONCE(parent != trace_instance_dir))
-		return -ENOENT;
-
-	/*
-	 * The inode mutex is locked, but debugfs_create_dir() will also
-	 * take the mutex. As the instances directory can not be destroyed
-	 * or changed in any other way, it is safe to unlock it, and
-	 * let the dentry try. If two users try to make the same dir at
-	 * the same time, then the new_instance_create() will determine the
-	 * winner.
-	 */
-	mutex_unlock(&inode->i_mutex);
-
-	ret = new_instance_create(dentry->d_iname);
-
-	mutex_lock(&inode->i_mutex);
-
-	return ret;
-}
-
-static int instance_rmdir(struct inode *inode, struct dentry *dentry)
-{
-	struct dentry *parent;
-	int ret;
-
-	/* Paranoid: Make sure the parent is the "instances" directory */
-	parent = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
-	if (WARN_ON_ONCE(parent != trace_instance_dir))
-		return -ENOENT;
-
-	/* The caller did a dget() on dentry */
-	mutex_unlock(&dentry->d_inode->i_mutex);
-
-	/*
-	 * The inode mutex is locked, but debugfs_create_dir() will also
-	 * take the mutex. As the instances directory can not be destroyed
-	 * or changed in any other way, it is safe to unlock it, and
-	 * let the dentry try. If two users try to make the same dir at
-	 * the same time, then the instance_delete() will determine the
-	 * winner.
-	 */
-	mutex_unlock(&inode->i_mutex);
-
-	ret = instance_delete(dentry->d_iname);
-
-	mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
-	mutex_lock(&dentry->d_inode->i_mutex);
-
-	return ret;
-}
-
-static const struct inode_operations instance_dir_inode_operations = {
-	.lookup		= simple_lookup,
-	.mkdir		= instance_mkdir,
-	.rmdir		= instance_rmdir,
-};
-
 static __init void create_trace_instances(struct dentry *d_tracer)
 {
-	trace_instance_dir = debugfs_create_dir("instances", d_tracer);
+	trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
+							 instance_mkdir,
+							 instance_rmdir);
 	if (WARN_ON(!trace_instance_dir))
 		return;
-
-	/* Hijack the dir inode operations, to allow mkdir */
-	trace_instance_dir->d_inode->i_op = &instance_dir_inode_operations;
 }
 
 static void
-init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
+init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 {
 	int cpu;
 
@@ -6511,10 +6467,32 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 #endif
 
 	for_each_tracing_cpu(cpu)
-		tracing_init_debugfs_percpu(tr, cpu);
+		tracing_init_tracefs_percpu(tr, cpu);
 
 }
 
+static struct vfsmount *trace_automount(void *ingore)
+{
+	struct vfsmount *mnt;
+	struct file_system_type *type;
+
+	/*
+	 * To maintain backward compatibility for tools that mount
+	 * debugfs to get to the tracing facility, tracefs is automatically
+	 * mounted to the debugfs/tracing directory.
+	 */
+	type = get_fs_type("tracefs");
+	if (!type)
+		return NULL;
+	mnt = vfs_kern_mount(type, 0, "tracefs", NULL);
+	put_filesystem(type);
+	if (IS_ERR(mnt))
+		return NULL;
+	mntget(mnt);
+
+	return mnt;
+}
+
 /**
  * tracing_init_dentry - initialize top level trace array
  *
@@ -6526,23 +6504,30 @@ struct dentry *tracing_init_dentry(void)
 {
 	struct trace_array *tr = &global_trace;
 
+	/* The top level trace array uses  NULL as parent */
 	if (tr->dir)
-		return tr->dir;
+		return NULL;
 
 	if (WARN_ON(!debugfs_initialized()))
 		return ERR_PTR(-ENODEV);
 
-	tr->dir = debugfs_create_dir("tracing", NULL);
-
+	/*
+	 * As there may still be users that expect the tracing
+	 * files to exist in debugfs/tracing, we must automount
+	 * the tracefs file system there, so older tools still
+	 * work with the newer kerenl.
+	 */
+	tr->dir = debugfs_create_automount("tracing", NULL,
+					   trace_automount, NULL);
 	if (!tr->dir) {
 		pr_warn_once("Could not create debugfs directory 'tracing'\n");
 		return ERR_PTR(-ENOMEM);
 	}
 
-	return tr->dir;
+	return NULL;
 }
 
-static __init int tracer_init_debugfs(void)
+static __init int tracer_init_tracefs(void)
 {
 	struct dentry *d_tracer;
 
@@ -6552,7 +6537,7 @@ static __init int tracer_init_debugfs(void)
 	if (IS_ERR(d_tracer))
 		return 0;
 
-	init_tracer_debugfs(&global_trace, d_tracer);
+	init_tracer_tracefs(&global_trace, d_tracer);
 
 	trace_create_file("tracing_thresh", 0644, d_tracer,
 			&global_trace, &tracing_thresh_fops);
@@ -6575,6 +6560,10 @@ static __init int tracer_init_debugfs(void)
 
 	create_trace_options_dir(&global_trace);
 
+	/* If the tracer was started via cmdline, create options for it here */
+	if (global_trace.current_trace != &nop_trace)
+		update_tracer_options(&global_trace, global_trace.current_trace);
+
 	return 0;
 }
 
@@ -6910,5 +6899,5 @@ __init static int clear_boot_tracer(void)
 	return 0;
 }
 
-fs_initcall(tracer_init_debugfs);
+fs_initcall(tracer_init_tracefs);
 late_initcall(clear_boot_tracer);