linux/include/linux/filelock.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FILELOCK_H
#define _LINUX_FILELOCK_H

#include <linux/fs.h>

#define FL_POSIX …
#define FL_FLOCK …
#define FL_DELEG …
#define FL_ACCESS …
#define FL_EXISTS …
#define FL_LEASE …
#define FL_CLOSE …
#define FL_SLEEP …
#define FL_DOWNGRADE_PENDING …
#define FL_UNLOCK_PENDING …
#define FL_OFDLCK …
#define FL_LAYOUT …
#define FL_RECLAIM …

#define FL_CLOSE_POSIX …

/*
 * Special return value from posix_lock_file() and vfs_lock_file() for
 * asynchronous locking.
 */
#define FILE_LOCK_DEFERRED …

struct file_lock;
struct file_lease;

struct file_lock_operations { … };

struct lock_manager_operations { … };

struct lease_manager_operations { … };

struct lock_manager { … };

struct net;
void locks_start_grace(struct net *, struct lock_manager *);
void locks_end_grace(struct lock_manager *);
bool locks_in_grace(struct net *);
bool opens_in_grace(struct net *);

/*
 * struct file_lock has a union that some filesystems use to track
 * their own private info. The NFS side of things is defined here:
 */
#include <linux/nfs_fs_i.h>

/*
 * struct file_lock represents a generic "file lock". It's used to represent
 * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
 * note that the same struct is used to represent both a request for a lock and
 * the lock itself, but the same object is never used for both.
 *
 * FIXME: should we create a separate "struct lock_request" to help distinguish
 * these two uses?
 *
 * The varous i_flctx lists are ordered by:
 *
 * 1) lock owner
 * 2) lock range start
 * 3) lock range end
 *
 * Obviously, the last two criteria only matter for POSIX locks.
 */

struct file_lock_core { … };

struct file_lock { … } __randomize_layout;

struct file_lease { … } __randomize_layout;

struct file_lock_context { … };

#ifdef CONFIG_FILE_LOCKING
int fcntl_getlk(struct file *, unsigned int, struct flock *);
int fcntl_setlk(unsigned int, struct file *, unsigned int,
			struct flock *);

#if BITS_PER_LONG == 32
int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
int fcntl_setlk64(unsigned int, struct file *, unsigned int,
			struct flock64 *);
#endif

int fcntl_setlease(unsigned int fd, struct file *filp, int arg);
int fcntl_getlease(struct file *filp);

static inline bool lock_is_unlock(struct file_lock *fl)
{ … }

static inline bool lock_is_read(struct file_lock *fl)
{ … }

static inline bool lock_is_write(struct file_lock *fl)
{ … }

static inline void locks_wake_up(struct file_lock *fl)
{ … }

/* fs/locks.c */
void locks_free_lock_context(struct inode *inode);
void locks_free_lock(struct file_lock *fl);
void locks_init_lock(struct file_lock *);
struct file_lock *locks_alloc_lock(void);
void locks_copy_lock(struct file_lock *, struct file_lock *);
void locks_copy_conflock(struct file_lock *, struct file_lock *);
void locks_remove_posix(struct file *, fl_owner_t);
void locks_remove_file(struct file *);
void locks_release_private(struct file_lock *);
void posix_test_lock(struct file *, struct file_lock *);
int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
int locks_delete_block(struct file_lock *);
int vfs_test_lock(struct file *, struct file_lock *);
int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
bool vfs_inode_has_locks(struct inode *inode);
int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);

void locks_init_lease(struct file_lease *);
void locks_free_lease(struct file_lease *fl);
struct file_lease *locks_alloc_lease(void);
int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
void lease_get_mtime(struct inode *, struct timespec64 *time);
int generic_setlease(struct file *, int, struct file_lease **, void **priv);
int kernel_setlease(struct file *, int, struct file_lease **, void **);
int vfs_setlease(struct file *, int, struct file_lease **, void **);
int lease_modify(struct file_lease *, int, struct list_head *);

struct notifier_block;
int lease_register_notifier(struct notifier_block *);
void lease_unregister_notifier(struct notifier_block *);

struct files_struct;
void show_fd_locks(struct seq_file *f,
			 struct file *filp, struct files_struct *files);
bool locks_owner_has_blockers(struct file_lock_context *flctx,
			fl_owner_t owner);

static inline struct file_lock_context *
locks_inode_context(const struct inode *inode)
{ … }

#else /* !CONFIG_FILE_LOCKING */
static inline int fcntl_getlk(struct file *file, unsigned int cmd,
			      struct flock __user *user)
{
	return -EINVAL;
}

static inline int fcntl_setlk(unsigned int fd, struct file *file,
			      unsigned int cmd, struct flock __user *user)
{
	return -EACCES;
}

#if BITS_PER_LONG == 32
static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
				struct flock64 *user)
{
	return -EINVAL;
}

static inline int fcntl_setlk64(unsigned int fd, struct file *file,
				unsigned int cmd, struct flock64 *user)
{
	return -EACCES;
}
#endif
static inline int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
{
	return -EINVAL;
}

static inline int fcntl_getlease(struct file *filp)
{
	return F_UNLCK;
}

static inline bool lock_is_unlock(struct file_lock *fl)
{
	return false;
}

static inline bool lock_is_read(struct file_lock *fl)
{
	return false;
}

static inline bool lock_is_write(struct file_lock *fl)
{
	return false;
}

static inline void locks_wake_up(struct file_lock *fl)
{
}

static inline void
locks_free_lock_context(struct inode *inode)
{
}

static inline void locks_init_lock(struct file_lock *fl)
{
	return;
}

static inline void locks_init_lease(struct file_lease *fl)
{
	return;
}

static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
{
	return;
}

static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
{
	return;
}

static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
{
	return;
}

static inline void locks_remove_file(struct file *filp)
{
	return;
}

static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
{
	return;
}

static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
				  struct file_lock *conflock)
{
	return -ENOLCK;
}

static inline int locks_delete_block(struct file_lock *waiter)
{
	return -ENOENT;
}

static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
{
	return 0;
}

static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
				struct file_lock *fl, struct file_lock *conf)
{
	return -ENOLCK;
}

static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
{
	return 0;
}

static inline bool vfs_inode_has_locks(struct inode *inode)
{
	return false;
}

static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
{
	return -ENOLCK;
}

static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
{
	return 0;
}

static inline void lease_get_mtime(struct inode *inode,
				   struct timespec64 *time)
{
	return;
}

static inline int generic_setlease(struct file *filp, int arg,
				    struct file_lease **flp, void **priv)
{
	return -EINVAL;
}

static inline int kernel_setlease(struct file *filp, int arg,
			       struct file_lease **lease, void **priv)
{
	return -EINVAL;
}

static inline int vfs_setlease(struct file *filp, int arg,
			       struct file_lease **lease, void **priv)
{
	return -EINVAL;
}

static inline int lease_modify(struct file_lease *fl, int arg,
			       struct list_head *dispose)
{
	return -EINVAL;
}

struct files_struct;
static inline void show_fd_locks(struct seq_file *f,
			struct file *filp, struct files_struct *files) {}
static inline bool locks_owner_has_blockers(struct file_lock_context *flctx,
			fl_owner_t owner)
{
	return false;
}

static inline struct file_lock_context *
locks_inode_context(const struct inode *inode)
{
	return NULL;
}

#endif /* !CONFIG_FILE_LOCKING */

/* for walking lists of file_locks linked by fl_list */
#define for_each_file_lock(_fl, _head) …

static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
{ … }

#ifdef CONFIG_FILE_LOCKING
static inline int break_lease(struct inode *inode, unsigned int mode)
{ … }

static inline int break_deleg(struct inode *inode, unsigned int mode)
{ … }

static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
{ … }

static inline int break_deleg_wait(struct inode **delegated_inode)
{ … }

static inline int break_layout(struct inode *inode, bool wait)
{ … }

#else /* !CONFIG_FILE_LOCKING */
static inline int break_lease(struct inode *inode, unsigned int mode)
{
	return 0;
}

static inline int break_deleg(struct inode *inode, unsigned int mode)
{
	return 0;
}

static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
{
	return 0;
}

static inline int break_deleg_wait(struct inode **delegated_inode)
{
	BUG();
	return 0;
}

static inline int break_layout(struct inode *inode, bool wait)
{
	return 0;
}

#endif /* CONFIG_FILE_LOCKING */

#endif /* _LINUX_FILELOCK_H */