btrfs: add simple debugfs interface
Help during debugging to export various interesting infromation and
tunables without the need of extra mount options or ioctls.
Usage:
* declare your variable in sysfs.h, and include where you need it
* define the variable in sysfs.c and make it visible via
debugfs_create_TYPE
Depends on CONFIG_DEBUG_FS.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 865f4cf..c5eb214 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -24,6 +24,7 @@
#include <linux/kobject.h>
#include <linux/bug.h>
#include <linux/genhd.h>
+#include <linux/debugfs.h>
#include "ctree.h"
#include "disk-io.h"
@@ -599,6 +600,12 @@
/* /sys/fs/btrfs/ entry */
static struct kset *btrfs_kset;
+/* /sys/kernel/debug/btrfs */
+static struct dentry *btrfs_debugfs_root_dentry;
+
+/* Debugging tunables and exported data */
+u64 btrfs_debugfs_test;
+
int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
{
int error;
@@ -642,27 +649,41 @@
return error;
}
+static int btrfs_init_debugfs(void)
+{
+#ifdef CONFIG_DEBUG_FS
+ btrfs_debugfs_root_dentry = debugfs_create_dir("btrfs", NULL);
+ if (!btrfs_debugfs_root_dentry)
+ return -ENOMEM;
+
+ debugfs_create_u64("test", S_IRUGO | S_IWUGO, btrfs_debugfs_root_dentry,
+ &btrfs_debugfs_test);
+#endif
+ return 0;
+}
+
int btrfs_init_sysfs(void)
{
int ret;
+
btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
if (!btrfs_kset)
return -ENOMEM;
- init_feature_attrs();
-
- ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
- if (ret) {
- kset_unregister(btrfs_kset);
+ ret = btrfs_init_debugfs();
+ if (ret)
return ret;
- }
- return 0;
+ init_feature_attrs();
+ ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
+
+ return ret;
}
void btrfs_exit_sysfs(void)
{
sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
kset_unregister(btrfs_kset);
+ debugfs_remove_recursive(btrfs_debugfs_root_dentry);
}