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>
---
v2:
- added missing return to btrfs_init_debugfs
- updated error handling to btrfs_init_sysfs, the cleanup
is done in btrfs_exit_sysfs
- removed #ifdef in btrfs_exit_sysfs,
fs/btrfs/sysfs.c | 33 +++++++++++++++++++++++++++------
1 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 782374d8fd19..b725e4574448 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"
@@ -593,6 +594,12 @@ static int add_device_membership(struct btrfs_fs_info
*fs_info)
/* /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;
@@ -636,27 +643,41 @@ failure:
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 = btrfs_init_debugfs();
+ if (ret)
+ return ret;
+ init_feature_attrs();
ret = sysfs_create_group(&btrfs_kset->kobj,
&btrfs_feature_attr_group);
- if (ret) {
- kset_unregister(btrfs_kset);
- return ret;
- }
- return 0;
+ 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);
}
--
1.7.9
--
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