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kernfs: move the last knowledge of sysfs out from kernfs

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There is still one residue of sysfs remaining: the sb_magic
SYSFS_MAGIC. However this should be kernfs user specific,
so this patch moves it out. Kerrnfs user should specify their
magic number while mouting.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jianyu Zhan 2014-04-26 15:40:28 +08:00 committed by Linus Torvalds
parent cae61ba37b
commit c9482a5bdc
4 changed files with 20 additions and 12 deletions
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11
fs/kernfs/mount.c
View File

@ -62,7 +62,7 @@ struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
return NULL;
}
static int kernfs_fill_super(struct super_block *sb)
static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
{
struct kernfs_super_info *info = kernfs_info(sb);
struct inode *inode;
@ -70,7 +70,7 @@ static int kernfs_fill_super(struct super_block *sb)
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = SYSFS_MAGIC;
sb->s_magic = magic;
sb->s_op = &kernfs_sops;
sb->s_time_gran = 1;
@ -131,6 +131,7 @@ const void *kernfs_super_ns(struct super_block *sb)
* @fs_type: file_system_type of the fs being mounted
* @flags: mount flags specified for the mount
* @root: kernfs_root of the hierarchy being mounted
* @magic: file system specific magic number
* @new_sb_created: tell the caller if we allocated a new superblock
* @ns: optional namespace tag of the mount
*
@ -142,8 +143,8 @@ const void *kernfs_super_ns(struct super_block *sb)
* The return value can be passed to the vfs layer verbatim.
*/
struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, bool *new_sb_created,
const void *ns)
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created, const void *ns)
{
struct super_block *sb;
struct kernfs_super_info *info;
@ -166,7 +167,7 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
*new_sb_created = !sb->s_root;
if (!sb->s_root) {
error = kernfs_fill_super(sb);
error = kernfs_fill_super(sb, magic);
if (error) {
deactivate_locked_super(sb);
return ERR_PTR(error);

4
fs/sysfs/mount.c
View File

@ -13,6 +13,7 @@
#define DEBUG
#include <linux/fs.h>
#include <linux/magic.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/user_namespace.h>
@ -38,7 +39,8 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
}
ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
root = kernfs_mount_ns(fs_type, flags, sysfs_root, &new_sb, ns);
root = kernfs_mount_ns(fs_type, flags, sysfs_root,
SYSFS_MAGIC, &new_sb, ns);
if (IS_ERR(root) || !new_sb)
kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
return root;

13
include/linux/kernfs.h
View File

@ -297,8 +297,8 @@ void kernfs_notify(struct kernfs_node *kn);
const void *kernfs_super_ns(struct super_block *sb);
struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, bool *new_sb_created,
const void *ns);
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created, const void *ns);
void kernfs_kill_sb(struct super_block *sb);
void kernfs_init(void);
@ -391,7 +391,8 @@ static inline const void *kernfs_super_ns(struct super_block *sb)
static inline struct dentry *
kernfs_mount_ns(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, bool *new_sb_created, const void *ns)
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created, const void *ns)
{ return ERR_PTR(-ENOSYS); }
static inline void kernfs_kill_sb(struct super_block *sb) { }
@ -449,9 +450,11 @@ static inline int kernfs_rename(struct kernfs_node *kn,
static inline struct dentry *
kernfs_mount(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, bool *new_sb_created)
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created)
{
return kernfs_mount_ns(fs_type, flags, root, new_sb_created, NULL);
return kernfs_mount_ns(fs_type, flags, root,
magic, new_sb_created, NULL);
}
#endif /* __LINUX_KERNFS_H */

4
kernel/cgroup.c
View File

@ -33,6 +33,7 @@
#include <linux/init_task.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/magic.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/mount.h>
@ -1604,7 +1605,8 @@ out_unlock:
if (ret)
return ERR_PTR(ret);
dentry = kernfs_mount(fs_type, flags, root->kf_root, &new_sb);
dentry = kernfs_mount(fs_type, flags, root->kf_root,
CGROUP_SUPER_MAGIC, &new_sb);
if (IS_ERR(dentry) || !new_sb)
cgroup_put(&root->cgrp);
return dentry;