Commit c9482a5b authored by Jianyu Zhan's avatar Jianyu Zhan Committed by Linus Torvalds
Browse files

kernfs: move the last knowledge of sysfs out from kernfs 



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: default avatarJianyu Zhan <nasa4836@gmail.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cae61ba3

fs/kernfs/mount.c

+6 −5
Original line number Diff line number Diff line
@@ -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);

fs/sysfs/mount.c

+3 −1
Original line number Diff line number Diff line
@@ -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;

include/linux/kernfs.h

+8 −5
Original line number Diff line number Diff line
@@ -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 */

kernel/cgroup.c

+3 −1
Original line number Diff line number Diff line
@@ -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;

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