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btrfs: add simple debugfs interface

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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>
This commit is contained in:
David Sterba 2014-02-05 15:36:18 +01:00 • committed by Josef Bacik
commit 1bae30982b
2 changed files with 33 additions and 7 deletions
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35
fs/btrfs/sysfs.c
View file

@ -24,6 +24,7 @@
#include <linux/kobject.h> #include <linux/kobject.h>
#include <linux/bug.h> #include <linux/bug.h>
#include <linux/genhd.h> #include <linux/genhd.h>
#include <linux/debugfs.h>
#include "ctree.h" #include "ctree.h"
#include "disk-io.h" #include "disk-io.h"
@ -599,6 +600,12 @@ static int add_device_membership(struct btrfs_fs_info *fs_info)
/* /sys/fs/btrfs/ entry */ /* /sys/fs/btrfs/ entry */
static struct kset *btrfs_kset; 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 btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
{ {
int error; int error;
@ -642,27 +649,41 @@ failure:
return error; 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 btrfs_init_sysfs(void)
{ {
int ret; int ret;
btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj); btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
if (!btrfs_kset) if (!btrfs_kset)
return -ENOMEM; return -ENOMEM;
init_feature_attrs(); ret = btrfs_init_debugfs();
if (ret)
ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
if (ret) {
kset_unregister(btrfs_kset);
return 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) void btrfs_exit_sysfs(void)
{ {
sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group); sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
kset_unregister(btrfs_kset); kset_unregister(btrfs_kset);
debugfs_remove_recursive(btrfs_debugfs_root_dentry);
} }

5
fs/btrfs/sysfs.h
View file

@ -1,6 +1,11 @@
#ifndef _BTRFS_SYSFS_H_ #ifndef _BTRFS_SYSFS_H_
#define _BTRFS_SYSFS_H_ #define _BTRFS_SYSFS_H_
/*
* Data exported through sysfs
*/
extern u64 btrfs_debugfs_test;
enum btrfs_feature_set { enum btrfs_feature_set {
FEAT_COMPAT, FEAT_COMPAT,
FEAT_COMPAT_RO, FEAT_COMPAT_RO,