summaryrefslogtreecommitdiffstats
path: root/include/linux/filelock.h
blob: 95e868e09e298bb70ca23ec760d1c00fdb07201e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
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, int 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 *, int, struct file_lock **, void **priv);
int vfs_setlease(struct file *, int, 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, int 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, int arg,
				    struct file_lock **flp, void **priv)
{
	return -EINVAL;
}

static inline int vfs_setlease(struct file *filp, int 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 */