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: 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>
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@ -62,7 +62,7 @@ struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
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return NULL;
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}
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static int kernfs_fill_super(struct super_block *sb)
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static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
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{
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struct kernfs_super_info *info = kernfs_info(sb);
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struct inode *inode;
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@ -70,7 +70,7 @@ static int kernfs_fill_super(struct super_block *sb)
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = SYSFS_MAGIC;
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sb->s_magic = magic;
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sb->s_op = &kernfs_sops;
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sb->s_time_gran = 1;
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@ -131,6 +131,7 @@ const void *kernfs_super_ns(struct super_block *sb)
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* @fs_type: file_system_type of the fs being mounted
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* @flags: mount flags specified for the mount
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* @root: kernfs_root of the hierarchy being mounted
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* @magic: file system specific magic number
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* @new_sb_created: tell the caller if we allocated a new superblock
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* @ns: optional namespace tag of the mount
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*
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@ -142,8 +143,8 @@ const void *kernfs_super_ns(struct super_block *sb)
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* The return value can be passed to the vfs layer verbatim.
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*/
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struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
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struct kernfs_root *root, bool *new_sb_created,
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const void *ns)
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struct kernfs_root *root, unsigned long magic,
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bool *new_sb_created, const void *ns)
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{
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struct super_block *sb;
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struct kernfs_super_info *info;
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@ -166,7 +167,7 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
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*new_sb_created = !sb->s_root;
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if (!sb->s_root) {
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error = kernfs_fill_super(sb);
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error = kernfs_fill_super(sb, magic);
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if (error) {
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deactivate_locked_super(sb);
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return ERR_PTR(error);
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@ -13,6 +13,7 @@
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#define DEBUG
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#include <linux/fs.h>
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#include <linux/magic.h>
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#include <linux/mount.h>
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#include <linux/init.h>
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#include <linux/user_namespace.h>
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@ -38,7 +39,8 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
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}
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ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
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root = kernfs_mount_ns(fs_type, flags, sysfs_root, &new_sb, ns);
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root = kernfs_mount_ns(fs_type, flags, sysfs_root,
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SYSFS_MAGIC, &new_sb, ns);
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if (IS_ERR(root) || !new_sb)
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kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
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return root;
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@ -297,8 +297,8 @@ void kernfs_notify(struct kernfs_node *kn);
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const void *kernfs_super_ns(struct super_block *sb);
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struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
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struct kernfs_root *root, bool *new_sb_created,
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const void *ns);
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struct kernfs_root *root, unsigned long magic,
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bool *new_sb_created, const void *ns);
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void kernfs_kill_sb(struct super_block *sb);
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void kernfs_init(void);
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@ -391,7 +391,8 @@ static inline const void *kernfs_super_ns(struct super_block *sb)
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static inline struct dentry *
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kernfs_mount_ns(struct file_system_type *fs_type, int flags,
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struct kernfs_root *root, bool *new_sb_created, const void *ns)
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struct kernfs_root *root, unsigned long magic,
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bool *new_sb_created, const void *ns)
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{ return ERR_PTR(-ENOSYS); }
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static inline void kernfs_kill_sb(struct super_block *sb) { }
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@ -449,9 +450,11 @@ static inline int kernfs_rename(struct kernfs_node *kn,
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static inline struct dentry *
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kernfs_mount(struct file_system_type *fs_type, int flags,
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struct kernfs_root *root, bool *new_sb_created)
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struct kernfs_root *root, unsigned long magic,
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bool *new_sb_created)
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{
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return kernfs_mount_ns(fs_type, flags, root, new_sb_created, NULL);
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return kernfs_mount_ns(fs_type, flags, root,
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magic, new_sb_created, NULL);
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}
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#endif /* __LINUX_KERNFS_H */
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@ -33,6 +33,7 @@
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#include <linux/init_task.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/magic.h>
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#include <linux/mm.h>
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#include <linux/mutex.h>
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#include <linux/mount.h>
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@ -1604,7 +1605,8 @@ out_unlock:
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if (ret)
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return ERR_PTR(ret);
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dentry = kernfs_mount(fs_type, flags, root->kf_root, &new_sb);
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dentry = kernfs_mount(fs_type, flags, root->kf_root,
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CGROUP_SUPER_MAGIC, &new_sb);
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if (IS_ERR(dentry) || !new_sb)
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cgroup_put(&root->cgrp);
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return dentry;
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