[linux-2.6-block.git] / fs / mount.h

/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/ns_common.h>
#include <linux/fs_pin.h>

extern struct list_head notify_list;

struct mnt_namespace {
	struct ns_common	ns;
	struct mount *	root;
	struct {
		struct rb_root	mounts;		 /* Protected by namespace_sem */
		struct rb_node	*mnt_last_node;	 /* last (rightmost) mount in the rbtree */
		struct rb_node	*mnt_first_node; /* first (leftmost) mount in the rbtree */
	};
	struct user_namespace	*user_ns;
	struct ucounts		*ucounts;
	u64			seq;	/* Sequence number to prevent loops */
	union {
		wait_queue_head_t	poll;
		struct rcu_head		mnt_ns_rcu;
	};
	u64			seq_origin; /* Sequence number of origin mount namespace */
	u64 event;
#ifdef CONFIG_FSNOTIFY
	__u32			n_fsnotify_mask;
	struct fsnotify_mark_connector __rcu *n_fsnotify_marks;
#endif
	unsigned int		nr_mounts; /* # of mounts in the namespace */
	unsigned int		pending_mounts;
	struct rb_node		mnt_ns_tree_node; /* node in the mnt_ns_tree */
	struct list_head	mnt_ns_list; /* entry in the sequential list of mounts namespace */
	refcount_t		passive; /* number references not pinning @mounts */
} __randomize_layout;

struct mnt_pcp {
	int mnt_count;
	int mnt_writers;
};

struct mountpoint {
	struct hlist_node m_hash;
	struct dentry *m_dentry;
	struct hlist_head m_list;
};

struct mount {
	struct hlist_node mnt_hash;
	struct mount *mnt_parent;
	struct dentry *mnt_mountpoint;
	struct vfsmount mnt;
	union {
		struct rb_node mnt_node; /* node in the ns->mounts rbtree */
		struct rcu_head mnt_rcu;
		struct llist_node mnt_llist;
	};
#ifdef CONFIG_SMP
	struct mnt_pcp __percpu *mnt_pcp;
#else
	int mnt_count;
	int mnt_writers;
#endif
	struct list_head mnt_mounts;	/* list of children, anchored here */
	struct list_head mnt_child;	/* and going through their mnt_child */
	struct list_head mnt_instance;	/* mount instance on sb->s_mounts */
	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
	struct list_head mnt_list;
	struct list_head mnt_expire;	/* link in fs-specific expiry list */
	struct list_head mnt_share;	/* circular list of shared mounts */
	struct hlist_head mnt_slave_list;/* list of slave mounts */
	struct hlist_node mnt_slave;	/* slave list entry */
	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
	struct mnt_namespace *mnt_ns;	/* containing namespace */
	struct mountpoint *mnt_mp;	/* where is it mounted */
	union {
		struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
		struct hlist_node mnt_umount;
	};
#ifdef CONFIG_FSNOTIFY
	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
	__u32 mnt_fsnotify_mask;
	struct list_head to_notify;	/* need to queue notification */
	struct mnt_namespace *prev_ns;	/* previous namespace (NULL if none) */
#endif
	int mnt_t_flags;		/* namespace_sem-protected flags */
	int mnt_id;			/* mount identifier, reused */
	u64 mnt_id_unique;		/* mount ID unique until reboot */
	int mnt_group_id;		/* peer group identifier */
	int mnt_expiry_mark;		/* true if marked for expiry */
	struct hlist_head mnt_pins;
	struct hlist_head mnt_stuck_children;
	struct mount *overmount;	/* mounted on ->mnt_root */
} __randomize_layout;

enum {
	T_SHARED		= 1, /* mount is shared */
	T_UNBINDABLE		= 2, /* mount is unbindable */
	T_MARKED		= 4, /* internal mark for propagate_... */
	T_UMOUNT_CANDIDATE	= 8, /* for propagate_umount */

	/*
	 * T_SHARED_MASK is the set of flags that should be cleared when a
	 * mount becomes shared.  Currently, this is only the flag that says a
	 * mount cannot be bind mounted, since this is how we create a mount
	 * that shares events with another mount.  If you add a new T_*
	 * flag, consider how it interacts with shared mounts.
	 */
	T_SHARED_MASK	= T_UNBINDABLE,
};

#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */

static inline struct mount *real_mount(struct vfsmount *mnt)
{
	return container_of(mnt, struct mount, mnt);
}

static inline int mnt_has_parent(const struct mount *mnt)
{
	return mnt != mnt->mnt_parent;
}

static inline int is_mounted(struct vfsmount *mnt)
{
	/* neither detached nor internal? */
	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
}

extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);

extern int __legitimize_mnt(struct vfsmount *, unsigned);

static inline bool __path_is_mountpoint(const struct path *path)
{
	struct mount *m = __lookup_mnt(path->mnt, path->dentry);
	return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
}

extern void __detach_mounts(struct dentry *dentry);

static inline void detach_mounts(struct dentry *dentry)
{
	if (!d_mountpoint(dentry))
		return;
	__detach_mounts(dentry);
}

static inline void get_mnt_ns(struct mnt_namespace *ns)
{
	refcount_inc(&ns->ns.count);
}

extern seqlock_t mount_lock;

struct proc_mounts {
	struct mnt_namespace *ns;
	struct path root;
	int (*show)(struct seq_file *, struct vfsmount *);
};

extern const struct seq_operations mounts_op;

extern bool __is_local_mountpoint(const struct dentry *dentry);
static inline bool is_local_mountpoint(const struct dentry *dentry)
{
	if (!d_mountpoint(dentry))
		return false;

	return __is_local_mountpoint(dentry);
}

static inline bool is_anon_ns(struct mnt_namespace *ns)
{
	return ns->seq == 0;
}

static inline bool anon_ns_root(const struct mount *m)
{
	struct mnt_namespace *ns = READ_ONCE(m->mnt_ns);

	return !IS_ERR_OR_NULL(ns) && is_anon_ns(ns) && m == ns->root;
}

static inline bool mnt_ns_attached(const struct mount *mnt)
{
	return !RB_EMPTY_NODE(&mnt->mnt_node);
}

static inline bool mnt_ns_empty(const struct mnt_namespace *ns)
{
	return RB_EMPTY_ROOT(&ns->mounts);
}

static inline void move_from_ns(struct mount *mnt)
{
	struct mnt_namespace *ns = mnt->mnt_ns;
	WARN_ON(!mnt_ns_attached(mnt));
	if (ns->mnt_last_node == &mnt->mnt_node)
		ns->mnt_last_node = rb_prev(&mnt->mnt_node);
	if (ns->mnt_first_node == &mnt->mnt_node)
		ns->mnt_first_node = rb_next(&mnt->mnt_node);
	rb_erase(&mnt->mnt_node, &ns->mounts);
	RB_CLEAR_NODE(&mnt->mnt_node);
}

bool has_locked_children(struct mount *mnt, struct dentry *dentry);
struct mnt_namespace *get_sequential_mnt_ns(struct mnt_namespace *mnt_ns,
					    bool previous);

static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
{
	return container_of(ns, struct mnt_namespace, ns);
}

#ifdef CONFIG_FSNOTIFY
static inline void mnt_notify_add(struct mount *m)
{
	/* Optimize the case where there are no watches */
	if ((m->mnt_ns && m->mnt_ns->n_fsnotify_marks) ||
	    (m->prev_ns && m->prev_ns->n_fsnotify_marks))
		list_add_tail(&m->to_notify, &notify_list);
	else
		m->prev_ns = m->mnt_ns;
}
#else
static inline void mnt_notify_add(struct mount *m)
{
}
#endif

struct mnt_namespace *mnt_ns_from_dentry(struct dentry *dentry);
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#include <linux/mount.h>
	3	#include <linux/seq_file.h>
	4	#include <linux/poll.h>
	5	#include <linux/ns_common.h>
	6	#include <linux/fs_pin.h>
	7
	8	extern struct list_head notify_list;
	9
	10	struct mnt_namespace {
	11	struct ns_common ns;
	12	struct mount * root;
	13	struct {
	14	struct rb_root mounts; /* Protected by namespace_sem */
	15	struct rb_node mnt_last_node; / last (rightmost) mount in the rbtree */
	16	struct rb_node mnt_first_node; / first (leftmost) mount in the rbtree */
	17	};
	18	struct user_namespace *user_ns;
	19	struct ucounts *ucounts;
	20	u64 seq; /* Sequence number to prevent loops */
	21	union {
	22	wait_queue_head_t poll;
	23	struct rcu_head mnt_ns_rcu;
	24	};
	25	u64 seq_origin; /* Sequence number of origin mount namespace */
	26	u64 event;
	27	#ifdef CONFIG_FSNOTIFY
	28	__u32 n_fsnotify_mask;
	29	struct fsnotify_mark_connector __rcu *n_fsnotify_marks;
	30	#endif
	31	unsigned int nr_mounts; /* # of mounts in the namespace */
	32	unsigned int pending_mounts;
	33	struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */
	34	struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */
	35	refcount_t passive; /* number references not pinning @mounts */
	36	} __randomize_layout;
	37
	38	struct mnt_pcp {
	39	int mnt_count;
	40	int mnt_writers;
	41	};
	42
	43	struct mountpoint {
	44	struct hlist_node m_hash;
	45	struct dentry *m_dentry;
	46	struct hlist_head m_list;
	47	};
	48
	49	struct mount {
	50	struct hlist_node mnt_hash;
	51	struct mount *mnt_parent;
	52	struct dentry *mnt_mountpoint;
	53	struct vfsmount mnt;
	54	union {
	55	struct rb_node mnt_node; /* node in the ns->mounts rbtree */
	56	struct rcu_head mnt_rcu;
	57	struct llist_node mnt_llist;
	58	};
	59	#ifdef CONFIG_SMP
	60	struct mnt_pcp __percpu *mnt_pcp;
	61	#else
	62	int mnt_count;
	63	int mnt_writers;
	64	#endif
	65	struct list_head mnt_mounts; /* list of children, anchored here */
	66	struct list_head mnt_child; /* and going through their mnt_child */
	67	struct list_head mnt_instance; /* mount instance on sb->s_mounts */
	68	const char mnt_devname; / Name of device e.g. /dev/dsk/hda1 */
	69	struct list_head mnt_list;
	70	struct list_head mnt_expire; /* link in fs-specific expiry list */
	71	struct list_head mnt_share; /* circular list of shared mounts */
	72	struct hlist_head mnt_slave_list;/* list of slave mounts */
	73	struct hlist_node mnt_slave; /* slave list entry */
	74	struct mount mnt_master; / slave is on master->mnt_slave_list */
	75	struct mnt_namespace mnt_ns; / containing namespace */
	76	struct mountpoint mnt_mp; / where is it mounted */
	77	union {
	78	struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */
	79	struct hlist_node mnt_umount;
	80	};
	81	#ifdef CONFIG_FSNOTIFY
	82	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
	83	__u32 mnt_fsnotify_mask;
	84	struct list_head to_notify; /* need to queue notification */
	85	struct mnt_namespace prev_ns; / previous namespace (NULL if none) */
	86	#endif
	87	int mnt_t_flags; /* namespace_sem-protected flags */
	88	int mnt_id; /* mount identifier, reused */
	89	u64 mnt_id_unique; /* mount ID unique until reboot */
	90	int mnt_group_id; /* peer group identifier */
	91	int mnt_expiry_mark; /* true if marked for expiry */
	92	struct hlist_head mnt_pins;
	93	struct hlist_head mnt_stuck_children;
	94	struct mount overmount; / mounted on ->mnt_root */
	95	} __randomize_layout;
	96
	97	enum {
	98	T_SHARED = 1, /* mount is shared */
	99	T_UNBINDABLE = 2, /* mount is unbindable */
	100	T_MARKED = 4, /* internal mark for propagate_... */
	101	T_UMOUNT_CANDIDATE = 8, /* for propagate_umount */
	102
	103	/*
	104	* T_SHARED_MASK is the set of flags that should be cleared when a
	105	* mount becomes shared. Currently, this is only the flag that says a
	106	* mount cannot be bind mounted, since this is how we create a mount
	107	* that shares events with another mount. If you add a new T_*
	108	* flag, consider how it interacts with shared mounts.
	109	*/
	110	T_SHARED_MASK = T_UNBINDABLE,
	111	};
	112
	113	#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
	114
	115	static inline struct mount real_mount(struct vfsmount mnt)
	116	{
	117	return container_of(mnt, struct mount, mnt);
	118	}
	119
	120	static inline int mnt_has_parent(const struct mount *mnt)
	121	{
	122	return mnt != mnt->mnt_parent;
	123	}
	124
	125	static inline int is_mounted(struct vfsmount *mnt)
	126	{
	127	/* neither detached nor internal? */
	128	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
	129	}
	130
	131	extern struct mount __lookup_mnt(struct vfsmount , struct dentry *);
	132
	133	extern int __legitimize_mnt(struct vfsmount *, unsigned);
	134
	135	static inline bool __path_is_mountpoint(const struct path *path)
	136	{
	137	struct mount *m = __lookup_mnt(path->mnt, path->dentry);
	138	return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
	139	}
	140
	141	extern void __detach_mounts(struct dentry *dentry);
	142
	143	static inline void detach_mounts(struct dentry *dentry)
	144	{
	145	if (!d_mountpoint(dentry))
	146	return;
	147	__detach_mounts(dentry);
	148	}
	149
	150	static inline void get_mnt_ns(struct mnt_namespace *ns)
	151	{
	152	refcount_inc(&ns->ns.count);
	153	}
	154
	155	extern seqlock_t mount_lock;
	156
	157	struct proc_mounts {
	158	struct mnt_namespace *ns;
	159	struct path root;
	160	int (show)(struct seq_file , struct vfsmount *);
	161	};
	162
	163	extern const struct seq_operations mounts_op;
	164
	165	extern bool __is_local_mountpoint(const struct dentry *dentry);
	166	static inline bool is_local_mountpoint(const struct dentry *dentry)
	167	{
	168	if (!d_mountpoint(dentry))
	169	return false;
	170
	171	return __is_local_mountpoint(dentry);
	172	}
	173
	174	static inline bool is_anon_ns(struct mnt_namespace *ns)
	175	{
	176	return ns->seq == 0;
	177	}
	178
	179	static inline bool anon_ns_root(const struct mount *m)
	180	{
	181	struct mnt_namespace *ns = READ_ONCE(m->mnt_ns);
	182
	183	return !IS_ERR_OR_NULL(ns) && is_anon_ns(ns) && m == ns->root;
	184	}
	185
	186	static inline bool mnt_ns_attached(const struct mount *mnt)
	187	{
	188	return !RB_EMPTY_NODE(&mnt->mnt_node);
	189	}
	190
	191	static inline bool mnt_ns_empty(const struct mnt_namespace *ns)
	192	{
	193	return RB_EMPTY_ROOT(&ns->mounts);
	194	}
	195
	196	static inline void move_from_ns(struct mount *mnt)
	197	{
	198	struct mnt_namespace *ns = mnt->mnt_ns;
	199	WARN_ON(!mnt_ns_attached(mnt));
	200	if (ns->mnt_last_node == &mnt->mnt_node)
	201	ns->mnt_last_node = rb_prev(&mnt->mnt_node);
	202	if (ns->mnt_first_node == &mnt->mnt_node)
	203	ns->mnt_first_node = rb_next(&mnt->mnt_node);
	204	rb_erase(&mnt->mnt_node, &ns->mounts);
	205	RB_CLEAR_NODE(&mnt->mnt_node);
	206	}
	207
	208	bool has_locked_children(struct mount mnt, struct dentry dentry);
	209	struct mnt_namespace get_sequential_mnt_ns(struct mnt_namespace mnt_ns,
	210	bool previous);
	211
	212	static inline struct mnt_namespace to_mnt_ns(struct ns_common ns)
	213	{
	214	return container_of(ns, struct mnt_namespace, ns);
	215	}
	216
	217	#ifdef CONFIG_FSNOTIFY
	218	static inline void mnt_notify_add(struct mount *m)
	219	{
	220	/* Optimize the case where there are no watches */
	221	if ((m->mnt_ns && m->mnt_ns->n_fsnotify_marks) \|\|
	222	(m->prev_ns && m->prev_ns->n_fsnotify_marks))
	223	list_add_tail(&m->to_notify, &notify_list);
	224	else
	225	m->prev_ns = m->mnt_ns;
	226	}
	227	#else
	228	static inline void mnt_notify_add(struct mount *m)
	229	{
	230	}
	231	#endif
	232
	233	struct mnt_namespace mnt_ns_from_dentry(struct dentry dentry);