[mirror_ubuntu-artful-kernel.git] / include / linux / kernfs.h

/*
 * kernfs.h - pseudo filesystem decoupled from vfs locking
 *
 * This file is released under the GPLv2.
 */

#ifndef __LINUX_KERNFS_H
#define __LINUX_KERNFS_H

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/lockdep.h>
#include <linux/rbtree.h>
#include <linux/atomic.h>
#include <linux/wait.h>

struct file;
struct dentry;
struct iattr;
struct seq_file;
struct vm_area_struct;
struct super_block;
struct file_system_type;

struct kernfs_open_node;
struct kernfs_iattrs;

enum kernfs_node_type {
	KERNFS_DIR		= 0x0001,
	KERNFS_FILE		= 0x0002,
	KERNFS_LINK		= 0x0004,
};

#define KERNFS_TYPE_MASK	0x000f
#define KERNFS_FLAG_MASK	~KERNFS_TYPE_MASK

enum kernfs_node_flag {
	KERNFS_ACTIVATED	= 0x0010,
	KERNFS_NS		= 0x0020,
	KERNFS_HAS_SEQ_SHOW	= 0x0040,
	KERNFS_HAS_MMAP		= 0x0080,
	KERNFS_LOCKDEP		= 0x0100,
	KERNFS_SUICIDAL		= 0x0400,
	KERNFS_SUICIDED		= 0x0800,
	KERNFS_EMPTY_DIR	= 0x1000,
};

/* @flags for kernfs_create_root() */
enum kernfs_root_flag {
	/*
	 * kernfs_nodes are created in the deactivated state and invisible.
	 * They require explicit kernfs_activate() to become visible.  This
	 * can be used to make related nodes become visible atomically
	 * after all nodes are created successfully.
	 */
	KERNFS_ROOT_CREATE_DEACTIVATED		= 0x0001,

	/*
	 * For regular flies, if the opener has CAP_DAC_OVERRIDE, open(2)
	 * succeeds regardless of the RW permissions.  sysfs had an extra
	 * layer of enforcement where open(2) fails with -EACCES regardless
	 * of CAP_DAC_OVERRIDE if the permission doesn't have the
	 * respective read or write access at all (none of S_IRUGO or
	 * S_IWUGO) or the respective operation isn't implemented.  The
	 * following flag enables that behavior.
	 */
	KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK	= 0x0002,
};

/* type-specific structures for kernfs_node union members */
struct kernfs_elem_dir {
	unsigned long		subdirs;
	/* children rbtree starts here and goes through kn->rb */
	struct rb_root		children;

	/*
	 * The kernfs hierarchy this directory belongs to.  This fits
	 * better directly in kernfs_node but is here to save space.
	 */
	struct kernfs_root	*root;
};

struct kernfs_elem_symlink {
	struct kernfs_node	*target_kn;
};

struct kernfs_elem_attr {
	const struct kernfs_ops	*ops;
	struct kernfs_open_node	*open;
	loff_t			size;
	struct kernfs_node	*notify_next;	/* for kernfs_notify() */
};

/*
 * kernfs_node - the building block of kernfs hierarchy.  Each and every
 * kernfs node is represented by single kernfs_node.  Most fields are
 * private to kernfs and shouldn't be accessed directly by kernfs users.
 *
 * As long as s_count reference is held, the kernfs_node itself is
 * accessible.  Dereferencing elem or any other outer entity requires
 * active reference.
 */
struct kernfs_node {
	atomic_t		count;
	atomic_t		active;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
	struct lockdep_map	dep_map;
#endif
	/*
	 * Use kernfs_get_parent() and kernfs_name/path() instead of
	 * accessing the following two fields directly.  If the node is
	 * never moved to a different parent, it is safe to access the
	 * parent directly.
	 */
	struct kernfs_node	*parent;
	const char		*name;

	struct rb_node		rb;

	const void		*ns;	/* namespace tag */
	unsigned int		hash;	/* ns + name hash */
	union {
		struct kernfs_elem_dir		dir;
		struct kernfs_elem_symlink	symlink;
		struct kernfs_elem_attr		attr;
	};

	void			*priv;

	unsigned short		flags;
	umode_t			mode;
	unsigned int		ino;
	struct kernfs_iattrs	*iattr;
};

/*
 * kernfs_syscall_ops may be specified on kernfs_create_root() to support
 * syscalls.  These optional callbacks are invoked on the matching syscalls
 * and can perform any kernfs operations which don't necessarily have to be
 * the exact operation requested.  An active reference is held for each
 * kernfs_node parameter.
 */
struct kernfs_syscall_ops {
	int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
	int (*show_options)(struct seq_file *sf, struct kernfs_root *root);

	int (*mkdir)(struct kernfs_node *parent, const char *name,
		     umode_t mode);
	int (*rmdir)(struct kernfs_node *kn);
	int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent,
		      const char *new_name);
};

struct kernfs_root {
	/* published fields */
	struct kernfs_node	*kn;
	unsigned int		flags;	/* KERNFS_ROOT_* flags */

	/* private fields, do not use outside kernfs proper */
	struct ida		ino_ida;
	struct kernfs_syscall_ops *syscall_ops;

	/* list of kernfs_super_info of this root, protected by kernfs_mutex */
	struct list_head	supers;

	wait_queue_head_t	deactivate_waitq;
};

struct kernfs_open_file {
	/* published fields */
	struct kernfs_node	*kn;
	struct file		*file;
	void			*priv;

	/* private fields, do not use outside kernfs proper */
	struct mutex		mutex;
	int			event;
	struct list_head	list;
	char			*prealloc_buf;

	size_t			atomic_write_len;
	bool			mmapped;
	const struct vm_operations_struct *vm_ops;
};

struct kernfs_ops {
	/*
	 * Read is handled by either seq_file or raw_read().
	 *
	 * If seq_show() is present, seq_file path is active.  Other seq
	 * operations are optional and if not implemented, the behavior is
	 * equivalent to single_open().  @sf->private points to the
	 * associated kernfs_open_file.
	 *
	 * read() is bounced through kernel buffer and a read larger than
	 * PAGE_SIZE results in partial operation of PAGE_SIZE.
	 */
	int (*seq_show)(struct seq_file *sf, void *v);

	void *(*seq_start)(struct seq_file *sf, loff_t *ppos);
	void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos);
	void (*seq_stop)(struct seq_file *sf, void *v);

	ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes,
			loff_t off);

	/*
	 * write() is bounced through kernel buffer.  If atomic_write_len
	 * is not set, a write larger than PAGE_SIZE results in partial
	 * operations of PAGE_SIZE chunks.  If atomic_write_len is set,
	 * writes upto the specified size are executed atomically but
	 * larger ones are rejected with -E2BIG.
	 */
	size_t atomic_write_len;
	/*
	 * "prealloc" causes a buffer to be allocated at open for
	 * all read/write requests.  As ->seq_show uses seq_read()
	 * which does its own allocation, it is incompatible with
	 * ->prealloc.  Provide ->read and ->write with ->prealloc.
	 */
	bool prealloc;
	ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes,
			 loff_t off);

	int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma);

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	struct lock_class_key	lockdep_key;
#endif
};

#ifdef CONFIG_KERNFS

static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
{
	return kn->flags & KERNFS_TYPE_MASK;
}

/**
 * kernfs_enable_ns - enable namespace under a directory
 * @kn: directory of interest, should be empty
 *
 * This is to be called right after @kn is created to enable namespace
 * under it.  All children of @kn must have non-NULL namespace tags and
 * only the ones which match the super_block's tag will be visible.
 */
static inline void kernfs_enable_ns(struct kernfs_node *kn)
{
	WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
	WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children));
	kn->flags |= KERNFS_NS;
}

/**
 * kernfs_ns_enabled - test whether namespace is enabled
 * @kn: the node to test
 *
 * Test whether namespace filtering is enabled for the children of @ns.
 */
static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
{
	return kn->flags & KERNFS_NS;
}

int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
size_t kernfs_path_len(struct kernfs_node *kn);
int kernfs_path_from_node(struct kernfs_node *root_kn, struct kernfs_node *kn,
			  char *buf, size_t buflen);
char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen);
void pr_cont_kernfs_name(struct kernfs_node *kn);
void pr_cont_kernfs_path(struct kernfs_node *kn);
struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
					   const char *name, const void *ns);
struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
					   const char *path, const void *ns);
void kernfs_get(struct kernfs_node *kn);
void kernfs_put(struct kernfs_node *kn);

struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry);
struct kernfs_root *kernfs_root_from_sb(struct super_block *sb);
struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn);

struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
				  struct super_block *sb);
struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
				       unsigned int flags, void *priv);
void kernfs_destroy_root(struct kernfs_root *root);

struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
					 const char *name, umode_t mode,
					 void *priv, const void *ns);
struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent,
					    const char *name);
struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
					 const char *name,
					 umode_t mode, loff_t size,
					 const struct kernfs_ops *ops,
					 void *priv, const void *ns,
					 struct lock_class_key *key);
struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
				       const char *name,
				       struct kernfs_node *target);
void kernfs_activate(struct kernfs_node *kn);
void kernfs_remove(struct kernfs_node *kn);
void kernfs_break_active_protection(struct kernfs_node *kn);
void kernfs_unbreak_active_protection(struct kernfs_node *kn);
bool kernfs_remove_self(struct kernfs_node *kn);
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
			     const void *ns);
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
		     const char *new_name, const void *new_ns);
int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
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, unsigned long magic,
			       bool *new_sb_created, const void *ns);
void kernfs_kill_sb(struct super_block *sb);
struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns);

void kernfs_init(void);

#else	/* CONFIG_KERNFS */

static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
{ return 0; }	/* whatever */

static inline void kernfs_enable_ns(struct kernfs_node *kn) { }

static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
{ return false; }

static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
{ return -ENOSYS; }

static inline size_t kernfs_path_len(struct kernfs_node *kn)
{ return 0; }

static inline char *kernfs_path(struct kernfs_node *kn, char *buf,
				size_t buflen)
{ return NULL; }

static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { }

static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
{ return NULL; }

static inline struct kernfs_node *
kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
		       const void *ns)
{ return NULL; }
static inline struct kernfs_node *
kernfs_walk_and_get_ns(struct kernfs_node *parent, const char *path,
		       const void *ns)
{ return NULL; }

static inline void kernfs_get(struct kernfs_node *kn) { }
static inline void kernfs_put(struct kernfs_node *kn) { }

static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
{ return NULL; }

static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
{ return NULL; }

static inline struct inode *
kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
{ return NULL; }

static inline struct kernfs_root *
kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags,
		   void *priv)
{ return ERR_PTR(-ENOSYS); }

static inline void kernfs_destroy_root(struct kernfs_root *root) { }

static inline struct kernfs_node *
kernfs_create_dir_ns(struct kernfs_node *parent, const char *name,
		     umode_t mode, void *priv, const void *ns)
{ return ERR_PTR(-ENOSYS); }

static inline struct kernfs_node *
__kernfs_create_file(struct kernfs_node *parent, const char *name,
		     umode_t mode, loff_t size, const struct kernfs_ops *ops,
		     void *priv, const void *ns, struct lock_class_key *key)
{ return ERR_PTR(-ENOSYS); }

static inline struct kernfs_node *
kernfs_create_link(struct kernfs_node *parent, const char *name,
		   struct kernfs_node *target)
{ return ERR_PTR(-ENOSYS); }

static inline void kernfs_activate(struct kernfs_node *kn) { }

static inline void kernfs_remove(struct kernfs_node *kn) { }

static inline bool kernfs_remove_self(struct kernfs_node *kn)
{ return false; }

static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
					   const char *name, const void *ns)
{ return -ENOSYS; }

static inline int kernfs_rename_ns(struct kernfs_node *kn,
				   struct kernfs_node *new_parent,
				   const char *new_name, const void *new_ns)
{ return -ENOSYS; }

static inline int kernfs_setattr(struct kernfs_node *kn,
				 const struct iattr *iattr)
{ return -ENOSYS; }

static inline void kernfs_notify(struct kernfs_node *kn) { }

static inline const void *kernfs_super_ns(struct super_block *sb)
{ return NULL; }

static inline struct dentry *
kernfs_mount_ns(struct file_system_type *fs_type, int flags,
		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) { }

static inline void kernfs_init(void) { }

#endif	/* CONFIG_KERNFS */

static inline struct kernfs_node *
kernfs_find_and_get(struct kernfs_node *kn, const char *name)
{
	return kernfs_find_and_get_ns(kn, name, NULL);
}

static inline struct kernfs_node *
kernfs_walk_and_get(struct kernfs_node *kn, const char *path)
{
	return kernfs_walk_and_get_ns(kn, path, NULL);
}

static inline struct kernfs_node *
kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode,
		  void *priv)
{
	return kernfs_create_dir_ns(parent, name, mode, priv, NULL);
}

static inline struct kernfs_node *
kernfs_create_file_ns(struct kernfs_node *parent, const char *name,
		      umode_t mode, loff_t size, const struct kernfs_ops *ops,
		      void *priv, const void *ns)
{
	struct lock_class_key *key = NULL;

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	key = (struct lock_class_key *)&ops->lockdep_key;
#endif
	return __kernfs_create_file(parent, name, mode, size, ops, priv, ns,
				    key);
}

static inline struct kernfs_node *
kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode,
		   loff_t size, const struct kernfs_ops *ops, void *priv)
{
	return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
}

static inline int kernfs_remove_by_name(struct kernfs_node *parent,
					const char *name)
{
	return kernfs_remove_by_name_ns(parent, name, NULL);
}

static inline int kernfs_rename(struct kernfs_node *kn,
				struct kernfs_node *new_parent,
				const char *new_name)
{
	return kernfs_rename_ns(kn, new_parent, new_name, NULL);
}

static inline struct dentry *
kernfs_mount(struct file_system_type *fs_type, int flags,
		struct kernfs_root *root, unsigned long magic,
		bool *new_sb_created)
{
	return kernfs_mount_ns(fs_type, flags, root,
				magic, new_sb_created, NULL);
}

#endif	/* __LINUX_KERNFS_H */
Commit	Line	Data
b8441ed2 TH	1	/*
	2	* kernfs.h - pseudo filesystem decoupled from vfs locking
	3	*
	4	* This file is released under the GPLv2.
	5	*/
	6
	7	#ifndef __LINUX_KERNFS_H
	8	#define __LINUX_KERNFS_H
	9
879f40d1	10	#include <linux/kernel.h>
5d0e26bb	11	#include <linux/err.h>
dd8a5b03 TH	12	#include <linux/list.h>
dd8a5b03 TH	13	#include <linux/mutex.h>
bc755553	14	#include <linux/idr.h>
517e64f5	15	#include <linux/lockdep.h>
cf9e5a73 TH	16	#include <linux/rbtree.h>
cf9e5a73 TH	17	#include <linux/atomic.h>
abd54f02	18	#include <linux/wait.h>
879f40d1	19
5d60418e	20	struct file;
917f56ca	21	struct dentry;
5d60418e	22	struct iattr;
dd8a5b03 TH	23	struct seq_file;
dd8a5b03 TH	24	struct vm_area_struct;
4b93dc9b TH	25	struct super_block;
4b93dc9b TH	26	struct file_system_type;
5d60418e	27
c525aadd TH	28	struct kernfs_open_node;
c525aadd TH	29	struct kernfs_iattrs;
cf9e5a73 TH	30
cf9e5a73 TH	31	enum kernfs_node_type {
df23fc39 TH	32	KERNFS_DIR = 0x0001,
	33	KERNFS_FILE = 0x0002,
	34	KERNFS_LINK = 0x0004,
cf9e5a73 TH	35	};
cf9e5a73 TH	36
df23fc39	37	#define KERNFS_TYPE_MASK 0x000f
df23fc39	38	#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK
cf9e5a73 TH	39
cf9e5a73 TH	40	enum kernfs_node_flag {
d35258ef	41	KERNFS_ACTIVATED = 0x0010,
df23fc39 TH	42	KERNFS_NS = 0x0020,
	43	KERNFS_HAS_SEQ_SHOW = 0x0040,
	44	KERNFS_HAS_MMAP = 0x0080,
	45	KERNFS_LOCKDEP = 0x0100,
6b0afc2a TH	46	KERNFS_SUICIDAL = 0x0400,
6b0afc2a TH	47	KERNFS_SUICIDED = 0x0800,
ea015218	48	KERNFS_EMPTY_DIR = 0x1000,
cf9e5a73 TH	49	};
cf9e5a73 TH	50
d35258ef TH	51	/* @flags for kernfs_create_root() */
d35258ef TH	52	enum kernfs_root_flag {
555724a8 TH	53	/*
	54	* kernfs_nodes are created in the deactivated state and invisible.
	55	* They require explicit kernfs_activate() to become visible. This
	56	* can be used to make related nodes become visible atomically
	57	* after all nodes are created successfully.
	58	*/
	59	KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
	60
	61	/*
	62	* For regular flies, if the opener has CAP_DAC_OVERRIDE, open(2)
	63	* succeeds regardless of the RW permissions. sysfs had an extra
	64	* layer of enforcement where open(2) fails with -EACCES regardless
	65	* of CAP_DAC_OVERRIDE if the permission doesn't have the
	66	* respective read or write access at all (none of S_IRUGO or
	67	* S_IWUGO) or the respective operation isn't implemented. The
	68	* following flag enables that behavior.
	69	*/
	70	KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK = 0x0002,
d35258ef TH	71	};
d35258ef TH	72
324a56e1 TH	73	/* type-specific structures for kernfs_node union members */
324a56e1 TH	74	struct kernfs_elem_dir {
cf9e5a73	75	unsigned long subdirs;
adc5e8b5	76	/* children rbtree starts here and goes through kn->rb */
cf9e5a73 TH	77	struct rb_root children;
	78
	79	/*
	80	* The kernfs hierarchy this directory belongs to. This fits
324a56e1	81	* better directly in kernfs_node but is here to save space.
cf9e5a73 TH	82	*/
	83	struct kernfs_root *root;
	84	};
	85
324a56e1 TH	86	struct kernfs_elem_symlink {
324a56e1 TH	87	struct kernfs_node *target_kn;
cf9e5a73 TH	88	};
cf9e5a73 TH	89
324a56e1	90	struct kernfs_elem_attr {
cf9e5a73	91	const struct kernfs_ops *ops;
c525aadd	92	struct kernfs_open_node *open;
cf9e5a73	93	loff_t size;
ecca47ce	94	struct kernfs_node notify_next; / for kernfs_notify() */
cf9e5a73 TH	95	};
	96
	97	/*
324a56e1 TH	98	* kernfs_node - the building block of kernfs hierarchy. Each and every
324a56e1 TH	99	* kernfs node is represented by single kernfs_node. Most fields are
cf9e5a73 TH	100	* private to kernfs and shouldn't be accessed directly by kernfs users.
cf9e5a73 TH	101	*
324a56e1 TH	102	* As long as s_count reference is held, the kernfs_node itself is
	103	* accessible. Dereferencing elem or any other outer entity requires
	104	* active reference.
cf9e5a73	105	*/
324a56e1	106	struct kernfs_node {
adc5e8b5 TH	107	atomic_t count;
adc5e8b5 TH	108	atomic_t active;
cf9e5a73 TH	109	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	110	struct lockdep_map dep_map;
	111	#endif
3eef34ad TH	112	/*
	113	* Use kernfs_get_parent() and kernfs_name/path() instead of
	114	* accessing the following two fields directly. If the node is
	115	* never moved to a different parent, it is safe to access the
	116	* parent directly.
	117	*/
adc5e8b5 TH	118	struct kernfs_node *parent;
adc5e8b5 TH	119	const char *name;
cf9e5a73	120
adc5e8b5	121	struct rb_node rb;
cf9e5a73	122
adc5e8b5	123	const void ns; / namespace tag */
9b0925a6	124	unsigned int hash; /* ns + name hash */
cf9e5a73	125	union {
adc5e8b5 TH	126	struct kernfs_elem_dir dir;
	127	struct kernfs_elem_symlink symlink;
	128	struct kernfs_elem_attr attr;
cf9e5a73 TH	129	};
	130
	131	void *priv;
	132
adc5e8b5 TH	133	unsigned short flags;
	134	umode_t mode;
	135	unsigned int ino;
c525aadd	136	struct kernfs_iattrs *iattr;
cf9e5a73	137	};
b8441ed2	138
80b9bbef	139	/*
90c07c89 TH	140	* kernfs_syscall_ops may be specified on kernfs_create_root() to support
	141	* syscalls. These optional callbacks are invoked on the matching syscalls
	142	* and can perform any kernfs operations which don't necessarily have to be
	143	* the exact operation requested. An active reference is held for each
	144	* kernfs_node parameter.
80b9bbef	145	*/
90c07c89	146	struct kernfs_syscall_ops {
6a7fed4e TH	147	int (remount_fs)(struct kernfs_root root, int flags, char data);
	148	int (show_options)(struct seq_file sf, struct kernfs_root *root);
	149
80b9bbef TH	150	int (mkdir)(struct kernfs_node parent, const char *name,
	151	umode_t mode);
	152	int (rmdir)(struct kernfs_node kn);
	153	int (rename)(struct kernfs_node kn, struct kernfs_node *new_parent,
	154	const char *new_name);
	155	};
	156
ba7443bc TH	157	struct kernfs_root {
ba7443bc TH	158	/* published fields */
324a56e1	159	struct kernfs_node *kn;
d35258ef	160	unsigned int flags; /* KERNFS_ROOT_* flags */
bc755553 TH	161
	162	/* private fields, do not use outside kernfs proper */
	163	struct ida ino_ida;
90c07c89	164	struct kernfs_syscall_ops *syscall_ops;
7d568a83 TH	165
	166	/* list of kernfs_super_info of this root, protected by kernfs_mutex */
	167	struct list_head supers;
	168
abd54f02	169	wait_queue_head_t deactivate_waitq;
ba7443bc TH	170	};
ba7443bc TH	171
c525aadd	172	struct kernfs_open_file {
dd8a5b03	173	/* published fields */
324a56e1	174	struct kernfs_node *kn;
dd8a5b03	175	struct file *file;
2536390d	176	void *priv;
dd8a5b03 TH	177
	178	/* private fields, do not use outside kernfs proper */
	179	struct mutex mutex;
	180	int event;
	181	struct list_head list;
2b75869b	182	char *prealloc_buf;
dd8a5b03	183
b7ce40cf	184	size_t atomic_write_len;
dd8a5b03 TH	185	bool mmapped;
	186	const struct vm_operations_struct *vm_ops;
	187	};
	188
f6acf8bb TH	189	struct kernfs_ops {
	190	/*
	191	* Read is handled by either seq_file or raw_read().
	192	*
d19b9846 TH	193	* If seq_show() is present, seq_file path is active. Other seq
	194	* operations are optional and if not implemented, the behavior is
	195	* equivalent to single_open(). @sf->private points to the
c525aadd	196	* associated kernfs_open_file.
f6acf8bb TH	197	*
	198	* read() is bounced through kernel buffer and a read larger than
	199	* PAGE_SIZE results in partial operation of PAGE_SIZE.
	200	*/
	201	int (seq_show)(struct seq_file sf, void *v);
d19b9846 TH	202
	203	void (seq_start)(struct seq_file sf, loff_t ppos);
	204	void (seq_next)(struct seq_file sf, void v, loff_t *ppos);
	205	void (seq_stop)(struct seq_file sf, void *v);
f6acf8bb	206
c525aadd	207	ssize_t (read)(struct kernfs_open_file of, char *buf, size_t bytes,
f6acf8bb TH	208	loff_t off);
	209
	210	/*
4d3773c4 TH	211	* write() is bounced through kernel buffer. If atomic_write_len
	212	* is not set, a write larger than PAGE_SIZE results in partial
	213	* operations of PAGE_SIZE chunks. If atomic_write_len is set,
	214	* writes upto the specified size are executed atomically but
	215	* larger ones are rejected with -E2BIG.
f6acf8bb	216	*/
4d3773c4	217	size_t atomic_write_len;
2b75869b N	218	/*
	219	* "prealloc" causes a buffer to be allocated at open for
	220	* all read/write requests. As ->seq_show uses seq_read()
	221	* which does its own allocation, it is incompatible with
	222	* ->prealloc. Provide ->read and ->write with ->prealloc.
	223	*/
	224	bool prealloc;
c525aadd	225	ssize_t (write)(struct kernfs_open_file of, char *buf, size_t bytes,
f6acf8bb TH	226	loff_t off);
f6acf8bb TH	227
c525aadd	228	int (mmap)(struct kernfs_open_file of, struct vm_area_struct *vma);
517e64f5 TH	229
	230	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	231	struct lock_class_key lockdep_key;
	232	#endif
f6acf8bb TH	233	};
f6acf8bb TH	234
ba341d55	235	#ifdef CONFIG_KERNFS
879f40d1	236
df23fc39	237	static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
cf9e5a73	238	{
df23fc39	239	return kn->flags & KERNFS_TYPE_MASK;
cf9e5a73 TH	240	}
	241
	242	/**
	243	* kernfs_enable_ns - enable namespace under a directory
324a56e1	244	* @kn: directory of interest, should be empty
cf9e5a73	245	*
324a56e1 TH	246	* This is to be called right after @kn is created to enable namespace
324a56e1 TH	247	* under it. All children of @kn must have non-NULL namespace tags and
cf9e5a73 TH	248	* only the ones which match the super_block's tag will be visible.
cf9e5a73 TH	249	*/
324a56e1	250	static inline void kernfs_enable_ns(struct kernfs_node *kn)
cf9e5a73	251	{
df23fc39	252	WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
adc5e8b5	253	WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children));
df23fc39	254	kn->flags \|= KERNFS_NS;
cf9e5a73 TH	255	}
cf9e5a73 TH	256
ac9bba03 TH	257	/**
ac9bba03 TH	258	* kernfs_ns_enabled - test whether namespace is enabled
324a56e1	259	* @kn: the node to test
ac9bba03 TH	260	*
	261	* Test whether namespace filtering is enabled for the children of @ns.
	262	*/
324a56e1	263	static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
ac9bba03	264	{
df23fc39	265	return kn->flags & KERNFS_NS;
ac9bba03 TH	266	}
ac9bba03 TH	267
3eef34ad	268	int kernfs_name(struct kernfs_node kn, char buf, size_t buflen);
9acee9c5	269	size_t kernfs_path_len(struct kernfs_node *kn);
9f6df573 AK	270	int kernfs_path_from_node(struct kernfs_node root_kn, struct kernfs_node kn,
	271	char *buf, size_t buflen);
	272	char kernfs_path(struct kernfs_node kn, char *buf, size_t buflen);
3eef34ad TH	273	void pr_cont_kernfs_name(struct kernfs_node *kn);
	274	void pr_cont_kernfs_path(struct kernfs_node *kn);
	275	struct kernfs_node kernfs_get_parent(struct kernfs_node kn);
324a56e1 TH	276	struct kernfs_node kernfs_find_and_get_ns(struct kernfs_node parent,
324a56e1 TH	277	const char name, const void ns);
bd96f76a TH	278	struct kernfs_node kernfs_walk_and_get_ns(struct kernfs_node parent,
bd96f76a TH	279	const char path, const void ns);
324a56e1 TH	280	void kernfs_get(struct kernfs_node *kn);
324a56e1 TH	281	void kernfs_put(struct kernfs_node *kn);
ccf73cf3	282
0c23b225 TH	283	struct kernfs_node kernfs_node_from_dentry(struct dentry dentry);
0c23b225 TH	284	struct kernfs_root kernfs_root_from_sb(struct super_block sb);
fb02915f	285	struct inode kernfs_get_inode(struct super_block sb, struct kernfs_node *kn);
0c23b225	286
fb3c8315 AK	287	struct dentry kernfs_node_dentry(struct kernfs_node kn,
fb3c8315 AK	288	struct super_block *sb);
90c07c89	289	struct kernfs_root kernfs_create_root(struct kernfs_syscall_ops scops,
d35258ef	290	unsigned int flags, void *priv);
ba7443bc TH	291	void kernfs_destroy_root(struct kernfs_root *root);
ba7443bc TH	292
324a56e1	293	struct kernfs_node kernfs_create_dir_ns(struct kernfs_node parent,
bb8b9d09 TH	294	const char *name, umode_t mode,
bb8b9d09 TH	295	void priv, const void ns);
ea015218 EB	296	struct kernfs_node kernfs_create_empty_dir(struct kernfs_node parent,
ea015218 EB	297	const char *name);
2063d608 TH	298	struct kernfs_node __kernfs_create_file(struct kernfs_node parent,
	299	const char *name,
	300	umode_t mode, loff_t size,
	301	const struct kernfs_ops *ops,
	302	void priv, const void ns,
2063d608	303	struct lock_class_key *key);
324a56e1 TH	304	struct kernfs_node kernfs_create_link(struct kernfs_node parent,
	305	const char *name,
	306	struct kernfs_node *target);
d35258ef	307	void kernfs_activate(struct kernfs_node *kn);
324a56e1	308	void kernfs_remove(struct kernfs_node *kn);
6b0afc2a TH	309	void kernfs_break_active_protection(struct kernfs_node *kn);
	310	void kernfs_unbreak_active_protection(struct kernfs_node *kn);
	311	bool kernfs_remove_self(struct kernfs_node *kn);
324a56e1	312	int kernfs_remove_by_name_ns(struct kernfs_node parent, const char name,
879f40d1	313	const void *ns);
324a56e1	314	int kernfs_rename_ns(struct kernfs_node kn, struct kernfs_node new_parent,
890ece16	315	const char new_name, const void new_ns);
324a56e1 TH	316	int kernfs_setattr(struct kernfs_node kn, const struct iattr iattr);
324a56e1 TH	317	void kernfs_notify(struct kernfs_node *kn);
879f40d1	318
4b93dc9b TH	319	const void kernfs_super_ns(struct super_block sb);
4b93dc9b TH	320	struct dentry kernfs_mount_ns(struct file_system_type fs_type, int flags,
26fc9cd2 JZ	321	struct kernfs_root *root, unsigned long magic,
26fc9cd2 JZ	322	bool new_sb_created, const void ns);
4b93dc9b	323	void kernfs_kill_sb(struct super_block *sb);
4e26445f	324	struct super_block kernfs_pin_sb(struct kernfs_root root, const void *ns);
4b93dc9b TH	325
	326	void kernfs_init(void);
	327
ba341d55	328	#else /* CONFIG_KERNFS */
879f40d1	329
df23fc39	330	static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
cf9e5a73 TH	331	{ return 0; } /* whatever */
cf9e5a73 TH	332
324a56e1	333	static inline void kernfs_enable_ns(struct kernfs_node *kn) { }
cf9e5a73	334
324a56e1	335	static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
ac9bba03 TH	336	{ return false; }
ac9bba03 TH	337
3eef34ad TH	338	static inline int kernfs_name(struct kernfs_node kn, char buf, size_t buflen)
	339	{ return -ENOSYS; }
	340
9acee9c5 TH	341	static inline size_t kernfs_path_len(struct kernfs_node *kn)
	342	{ return 0; }
	343
9f6df573 AK	344	static inline char kernfs_path(struct kernfs_node kn, char *buf,
9f6df573 AK	345	size_t buflen)
3eef34ad TH	346	{ return NULL; }
	347
	348	static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
	349	static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { }
	350
	351	static inline struct kernfs_node kernfs_get_parent(struct kernfs_node kn)
	352	{ return NULL; }
	353
324a56e1 TH	354	static inline struct kernfs_node *
324a56e1 TH	355	kernfs_find_and_get_ns(struct kernfs_node parent, const char name,
ccf73cf3 TH	356	const void *ns)
ccf73cf3 TH	357	{ return NULL; }
bd96f76a TH	358	static inline struct kernfs_node *
	359	kernfs_walk_and_get_ns(struct kernfs_node parent, const char path,
	360	const void *ns)
	361	{ return NULL; }
ccf73cf3	362
324a56e1 TH	363	static inline void kernfs_get(struct kernfs_node *kn) { }
324a56e1 TH	364	static inline void kernfs_put(struct kernfs_node *kn) { }
ccf73cf3	365
0c23b225 TH	366	static inline struct kernfs_node kernfs_node_from_dentry(struct dentry dentry)
	367	{ return NULL; }
	368
	369	static inline struct kernfs_root kernfs_root_from_sb(struct super_block sb)
	370	{ return NULL; }
	371
fb02915f TH	372	static inline struct inode *
	373	kernfs_get_inode(struct super_block sb, struct kernfs_node kn)
	374	{ return NULL; }
	375
80b9bbef	376	static inline struct kernfs_root *
d35258ef TH	377	kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags,
d35258ef TH	378	void *priv)
ba7443bc TH	379	{ return ERR_PTR(-ENOSYS); }
	380
	381	static inline void kernfs_destroy_root(struct kernfs_root *root) { }
	382
324a56e1	383	static inline struct kernfs_node *
bb8b9d09 TH	384	kernfs_create_dir_ns(struct kernfs_node parent, const char name,
bb8b9d09 TH	385	umode_t mode, void priv, const void ns)
93b2b8e4 TH	386	{ return ERR_PTR(-ENOSYS); }
93b2b8e4 TH	387
324a56e1	388	static inline struct kernfs_node *
2063d608 TH	389	__kernfs_create_file(struct kernfs_node parent, const char name,
2063d608 TH	390	umode_t mode, loff_t size, const struct kernfs_ops *ops,
dfeb0750	391	void priv, const void ns, struct lock_class_key *key)
496f7394 TH	392	{ return ERR_PTR(-ENOSYS); }
496f7394 TH	393
324a56e1 TH	394	static inline struct kernfs_node *
	395	kernfs_create_link(struct kernfs_node parent, const char name,
	396	struct kernfs_node *target)
5d0e26bb TH	397	{ return ERR_PTR(-ENOSYS); }
5d0e26bb TH	398
d35258ef TH	399	static inline void kernfs_activate(struct kernfs_node *kn) { }
d35258ef TH	400
324a56e1	401	static inline void kernfs_remove(struct kernfs_node *kn) { }
879f40d1	402
6b0afc2a TH	403	static inline bool kernfs_remove_self(struct kernfs_node *kn)
	404	{ return false; }
	405
324a56e1	406	static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
879f40d1 TH	407	const char name, const void ns)
	408	{ return -ENOSYS; }
	409
324a56e1 TH	410	static inline int kernfs_rename_ns(struct kernfs_node *kn,
324a56e1 TH	411	struct kernfs_node *new_parent,
890ece16 TH	412	const char new_name, const void new_ns)
	413	{ return -ENOSYS; }
	414
324a56e1	415	static inline int kernfs_setattr(struct kernfs_node *kn,
5d60418e TH	416	const struct iattr *iattr)
	417	{ return -ENOSYS; }
	418
324a56e1	419	static inline void kernfs_notify(struct kernfs_node *kn) { }
024f6471	420
4b93dc9b TH	421	static inline const void kernfs_super_ns(struct super_block sb)
	422	{ return NULL; }
	423
	424	static inline struct dentry *
	425	kernfs_mount_ns(struct file_system_type *fs_type, int flags,
26fc9cd2 JZ	426	struct kernfs_root *root, unsigned long magic,
26fc9cd2 JZ	427	bool new_sb_created, const void ns)
4b93dc9b TH	428	{ return ERR_PTR(-ENOSYS); }
	429
	430	static inline void kernfs_kill_sb(struct super_block *sb) { }
	431
	432	static inline void kernfs_init(void) { }
	433
ba341d55	434	#endif /* CONFIG_KERNFS */
879f40d1	435
324a56e1 TH	436	static inline struct kernfs_node *
324a56e1 TH	437	kernfs_find_and_get(struct kernfs_node kn, const char name)
ccf73cf3	438	{
324a56e1	439	return kernfs_find_and_get_ns(kn, name, NULL);
ccf73cf3 TH	440	}
ccf73cf3 TH	441
bd96f76a TH	442	static inline struct kernfs_node *
	443	kernfs_walk_and_get(struct kernfs_node kn, const char path)
	444	{
	445	return kernfs_walk_and_get_ns(kn, path, NULL);
	446	}
	447
324a56e1	448	static inline struct kernfs_node *
bb8b9d09 TH	449	kernfs_create_dir(struct kernfs_node parent, const char name, umode_t mode,
bb8b9d09 TH	450	void *priv)
93b2b8e4	451	{
bb8b9d09	452	return kernfs_create_dir_ns(parent, name, mode, priv, NULL);
93b2b8e4 TH	453	}
93b2b8e4 TH	454
324a56e1 TH	455	static inline struct kernfs_node *
324a56e1 TH	456	kernfs_create_file_ns(struct kernfs_node parent, const char name,
517e64f5 TH	457	umode_t mode, loff_t size, const struct kernfs_ops *ops,
	458	void priv, const void ns)
	459	{
	460	struct lock_class_key *key = NULL;
	461
	462	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	463	key = (struct lock_class_key *)&ops->lockdep_key;
	464	#endif
2063d608	465	return __kernfs_create_file(parent, name, mode, size, ops, priv, ns,
dfeb0750	466	key);
517e64f5 TH	467	}
517e64f5 TH	468
324a56e1 TH	469	static inline struct kernfs_node *
324a56e1 TH	470	kernfs_create_file(struct kernfs_node parent, const char name, umode_t mode,
496f7394 TH	471	loff_t size, const struct kernfs_ops ops, void priv)
	472	{
	473	return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
	474	}
	475
324a56e1	476	static inline int kernfs_remove_by_name(struct kernfs_node *parent,
879f40d1 TH	477	const char *name)
	478	{
	479	return kernfs_remove_by_name_ns(parent, name, NULL);
	480	}
	481
0c23b225 TH	482	static inline int kernfs_rename(struct kernfs_node *kn,
	483	struct kernfs_node *new_parent,
	484	const char *new_name)
	485	{
	486	return kernfs_rename_ns(kn, new_parent, new_name, NULL);
	487	}
	488
4b93dc9b TH	489	static inline struct dentry *
4b93dc9b TH	490	kernfs_mount(struct file_system_type *fs_type, int flags,
26fc9cd2 JZ	491	struct kernfs_root *root, unsigned long magic,
26fc9cd2 JZ	492	bool *new_sb_created)
4b93dc9b	493	{
26fc9cd2 JZ	494	return kernfs_mount_ns(fs_type, flags, root,
26fc9cd2 JZ	495	magic, new_sb_created, NULL);
4b93dc9b TH	496	}
4b93dc9b TH	497
b8441ed2	498	#endif /* __LINUX_KERNFS_H */