1 files changed, 439 insertions, 0 deletions
diff --git a/include/linux/filelock.h b/include/linux/filelock.h
new file mode 100644
index 000000000000..efcdd1631d9b
--- /dev/null
+++ b/include/linux/filelock.h
@@ -0,0 +1,439 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_FILELOCK_H
+#define _LINUX_FILELOCK_H
+
+#include <linux/fs.h>
+
+#define FL_POSIX	1
+#define FL_FLOCK	2
+#define FL_DELEG	4	/* NFSv4 delegation */
+#define FL_ACCESS	8	/* not trying to lock, just looking */
+#define FL_EXISTS	16	/* when unlocking, test for existence */
+#define FL_LEASE	32	/* lease held on this file */
+#define FL_CLOSE	64	/* unlock on close */
+#define FL_SLEEP	128	/* A blocking lock */
+#define FL_DOWNGRADE_PENDING	256 /* Lease is being downgraded */
+#define FL_UNLOCK_PENDING	512 /* Lease is being broken */
+#define FL_OFDLCK	1024	/* lock is "owned" by struct file */
+#define FL_LAYOUT	2048	/* outstanding pNFS layout */
+#define FL_RECLAIM	4096	/* reclaiming from a reboot server */
+
+#define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
+
+/*
+ * Special return value from posix_lock_file() and vfs_lock_file() for
+ * asynchronous locking.
+ */
+#define FILE_LOCK_DEFERRED 1
+
+struct file_lock;
+
+struct file_lock_operations {
+	void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
+	void (*fl_release_private)(struct file_lock *);
+};
+
+struct lock_manager_operations {
+	void *lm_mod_owner;
+	fl_owner_t (*lm_get_owner)(fl_owner_t);
+	void (*lm_put_owner)(fl_owner_t);
+	void (*lm_notify)(struct file_lock *);	/* unblock callback */
+	int (*lm_grant)(struct file_lock *, int);
+	bool (*lm_break)(struct file_lock *);
+	int (*lm_change)(struct file_lock *, int, struct list_head *);
+	void (*lm_setup)(struct file_lock *, void **);
+	bool (*lm_breaker_owns_lease)(struct file_lock *);
+	bool (*lm_lock_expirable)(struct file_lock *cfl);
+	void (*lm_expire_lock)(void);
+};
+
+struct lock_manager {
+	struct list_head list;
+	/*
+	 * NFSv4 and up also want opens blocked during the grace period;
+	 * NLM doesn't care:
+	 */
+	bool block_opens;
+};
+
+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 {
+	struct file_lock *fl_blocker;	/* The lock, that is blocking us */
+	struct list_head fl_list;	/* link into file_lock_context */
+	struct hlist_node fl_link;	/* node in global lists */
+	struct list_head fl_blocked_requests;	/* list of requests with
+						 * ->fl_blocker pointing here
+						 */
+	struct list_head fl_blocked_member;	/* node in
+						 * ->fl_blocker->fl_blocked_requests
+						 */
+	fl_owner_t fl_owner;
+	unsigned int fl_flags;
+	unsigned char fl_type;
+	unsigned int fl_pid;
+	int fl_link_cpu;		/* what cpu's list is this on? */
+	wait_queue_head_t fl_wait;
+	struct file *fl_file;
+	loff_t fl_start;
+	loff_t fl_end;
+
+	struct fasync_struct *	fl_fasync; /* for lease break notifications */
+	/* for lease breaks: */
+	unsigned long fl_break_time;
+	unsigned long fl_downgrade_time;
+
+	const struct file_lock_operations *fl_ops;	/* Callbacks for filesystems */
+	const struct lock_manager_operations *fl_lmops;	/* Callbacks for lockmanagers */
+	union {
+		struct nfs_lock_info	nfs_fl;
+		struct nfs4_lock_info	nfs4_fl;
+		struct {
+			struct list_head link;	/* link in AFS vnode's pending_locks list */
+			int state;		/* state of grant or error if -ve */
+			unsigned int	debug_id;
+		} afs;
+		struct {
+			struct inode *inode;
+		} ceph;
+	} fl_u;
+} __randomize_layout;
+
+struct file_lock_context {
+	spinlock_t		flc_lock;
+	struct list_head	flc_flock;
+	struct list_head	flc_posix;
+	struct list_head	flc_lease;
+};
+
+#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, long arg);
+int fcntl_getlease(struct file *filp);
+
+/* 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);
+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 *, long, struct file_lock **, void **priv);
+int vfs_setlease(struct file *, long, struct file_lock **, void **);
+int lease_modify(struct file_lock *, 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)
+{
+	return smp_load_acquire(&inode->i_flctx);
+}
+
+#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, long arg)
+{
+	return -EINVAL;
+}
+
+static inline int fcntl_getlease(struct file *filp)
+{
+	return F_UNLCK;
+}
+
+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_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, long arg,
+				    struct file_lock **flp, void **priv)
+{
+	return -EINVAL;
+}
+
+static inline int vfs_setlease(struct file *filp, long arg,
+			       struct file_lock **lease, void **priv)
+{
+	return -EINVAL;
+}
+
+static inline int lease_modify(struct file_lock *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 */
+
+static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
+{
+	return locks_lock_inode_wait(file_inode(filp), fl);
+}
+
+#ifdef CONFIG_FILE_LOCKING
+static inline int break_lease(struct inode *inode, unsigned int mode)
+{
+	/*
+	 * Since this check is lockless, we must ensure that any refcounts
+	 * taken are done before checking i_flctx->flc_lease. Otherwise, we
+	 * could end up racing with tasks trying to set a new lease on this
+	 * file.
+	 */
+	smp_mb();
+	if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
+		return __break_lease(inode, mode, FL_LEASE);
+	return 0;
+}
+
+static inline int break_deleg(struct inode *inode, unsigned int mode)
+{
+	/*
+	 * Since this check is lockless, we must ensure that any refcounts
+	 * taken are done before checking i_flctx->flc_lease. Otherwise, we
+	 * could end up racing with tasks trying to set a new lease on this
+	 * file.
+	 */
+	smp_mb();
+	if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
+		return __break_lease(inode, mode, FL_DELEG);
+	return 0;
+}
+
+static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
+{
+	int ret;
+
+	ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
+	if (ret == -EWOULDBLOCK && delegated_inode) {
+		*delegated_inode = inode;
+		ihold(inode);
+	}
+	return ret;
+}
+
+static inline int break_deleg_wait(struct inode **delegated_inode)
+{
+	int ret;
+
+	ret = break_deleg(*delegated_inode, O_WRONLY);
+	iput(*delegated_inode);
+	*delegated_inode = NULL;
+	return ret;
+}
+
+static inline int break_layout(struct inode *inode, bool wait)
+{
+	smp_mb();
+	if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
+		return __break_lease(inode,
+				wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
+				FL_LAYOUT);
+	return 0;
+}
+
+#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 */