1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_FILELOCK_H
3 #define _LINUX_FILELOCK_H
4
5 #include <linux/fs.h>
6
7 #define FL_POSIX 1
8 #define FL_FLOCK 2
9 #define FL_DELEG 4 /* NFSv4 delegation */
10 #define FL_ACCESS 8 /* not trying to lock, just looking */
11 #define FL_EXISTS 16 /* when unlocking, test for existence */
12 #define FL_LEASE 32 /* lease held on this file */
13 #define FL_CLOSE 64 /* unlock on close */
14 #define FL_SLEEP 128 /* A blocking lock */
15 #define FL_DOWNGRADE_PENDING 256 /* Lease is being downgraded */
16 #define FL_UNLOCK_PENDING 512 /* Lease is being broken */
17 #define FL_OFDLCK 1024 /* lock is "owned" by struct file */
18 #define FL_LAYOUT 2048 /* outstanding pNFS layout */
19 #define FL_RECLAIM 4096 /* reclaiming from a reboot server */
20
21 #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
22
23 /*
24 * Special return value from posix_lock_file() and vfs_lock_file() for
25 * asynchronous locking.
26 */
27 #define FILE_LOCK_DEFERRED 1
28
29 struct file_lock;
30 struct file_lease;
31
32 struct file_lock_operations {
33 void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
34 void (*fl_release_private)(struct file_lock *);
35 };
36
37 struct lock_manager_operations {
38 void *lm_mod_owner;
39 fl_owner_t (*lm_get_owner)(fl_owner_t);
40 void (*lm_put_owner)(fl_owner_t);
41 void (*lm_notify)(struct file_lock *); /* unblock callback */
42 int (*lm_grant)(struct file_lock *, int);
43 bool (*lm_lock_expirable)(struct file_lock *cfl);
44 void (*lm_expire_lock)(void);
45 };
46
47 struct lease_manager_operations {
48 bool (*lm_break)(struct file_lease *);
49 int (*lm_change)(struct file_lease *, int, struct list_head *);
50 void (*lm_setup)(struct file_lease *, void **);
51 bool (*lm_breaker_owns_lease)(struct file_lease *);
52 };
53
54 struct lock_manager {
55 struct list_head list;
56 /*
57 * NFSv4 and up also want opens blocked during the grace period;
58 * NLM doesn't care:
59 */
60 bool block_opens;
61 };
62
63 struct net;
64 void locks_start_grace(struct net *, struct lock_manager *);
65 void locks_end_grace(struct lock_manager *);
66 bool locks_in_grace(struct net *);
67 bool opens_in_grace(struct net *);
68
69 /*
70 * struct file_lock has a union that some filesystems use to track
71 * their own private info. The NFS side of things is defined here:
72 */
73 #include <linux/nfs_fs_i.h>
74
75 /*
76 * struct file_lock represents a generic "file lock". It's used to represent
77 * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
78 * note that the same struct is used to represent both a request for a lock and
79 * the lock itself, but the same object is never used for both.
80 *
81 * FIXME: should we create a separate "struct lock_request" to help distinguish
82 * these two uses?
83 *
84 * The varous i_flctx lists are ordered by:
85 *
86 * 1) lock owner
87 * 2) lock range start
88 * 3) lock range end
89 *
90 * Obviously, the last two criteria only matter for POSIX locks.
91 */
92
93 struct file_lock_core {
94 struct file_lock_core *flc_blocker; /* The lock that is blocking us */
95 struct list_head flc_list; /* link into file_lock_context */
96 struct hlist_node flc_link; /* node in global lists */
97 struct list_head flc_blocked_requests; /* list of requests with
98 * ->fl_blocker pointing here
99 */
100 struct list_head flc_blocked_member; /* node in
101 * ->fl_blocker->fl_blocked_requests
102 */
103 fl_owner_t flc_owner;
104 unsigned int flc_flags;
105 unsigned char flc_type;
106 pid_t flc_pid;
107 int flc_link_cpu; /* what cpu's list is this on? */
108 wait_queue_head_t flc_wait;
109 struct file *flc_file;
110 };
111
112 struct file_lock {
113 struct file_lock_core c;
114 loff_t fl_start;
115 loff_t fl_end;
116
117 const struct file_lock_operations *fl_ops; /* Callbacks for filesystems */
118 const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
119 union {
120 struct nfs_lock_info nfs_fl;
121 struct nfs4_lock_info nfs4_fl;
122 struct {
123 struct list_head link; /* link in AFS vnode's pending_locks list */
124 int state; /* state of grant or error if -ve */
125 unsigned int debug_id;
126 } afs;
127 struct {
128 struct inode *inode;
129 } ceph;
130 } fl_u;
131 } __randomize_layout;
132
133 struct file_lease {
134 struct file_lock_core c;
135 struct fasync_struct * fl_fasync; /* for lease break notifications */
136 /* for lease breaks: */
137 unsigned long fl_break_time;
138 unsigned long fl_downgrade_time;
139 const struct lease_manager_operations *fl_lmops; /* Callbacks for lease managers */
140 } __randomize_layout;
141
142 struct file_lock_context {
143 spinlock_t flc_lock;
144 struct list_head flc_flock;
145 struct list_head flc_posix;
146 struct list_head flc_lease;
147 };
148
149 #ifdef CONFIG_FILE_LOCKING
150 int fcntl_getlk(struct file *, unsigned int, struct flock *);
151 int fcntl_setlk(unsigned int, struct file *, unsigned int,
152 struct flock *);
153
154 #if BITS_PER_LONG == 32
155 int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
156 int fcntl_setlk64(unsigned int, struct file *, unsigned int,
157 struct flock64 *);
158 #endif
159
160 int fcntl_setlease(unsigned int fd, struct file *filp, int arg);
161 int fcntl_getlease(struct file *filp);
162
163 static inline bool lock_is_unlock(struct file_lock *fl)
164 {
165 return fl->c.flc_type == F_UNLCK;
166 }
167
168 static inline bool lock_is_read(struct file_lock *fl)
169 {
170 return fl->c.flc_type == F_RDLCK;
171 }
172
173 static inline bool lock_is_write(struct file_lock *fl)
174 {
175 return fl->c.flc_type == F_WRLCK;
176 }
177
178 static inline void locks_wake_up(struct file_lock *fl)
179 {
180 wake_up(&fl->c.flc_wait);
181 }
182
183 /* fs/locks.c */
184 void locks_free_lock_context(struct inode *inode);
185 void locks_free_lock(struct file_lock *fl);
186 void locks_init_lock(struct file_lock *);
187 struct file_lock *locks_alloc_lock(void);
188 void locks_copy_lock(struct file_lock *, struct file_lock *);
189 void locks_copy_conflock(struct file_lock *, struct file_lock *);
190 void locks_remove_posix(struct file *, fl_owner_t);
191 void locks_remove_file(struct file *);
192 void locks_release_private(struct file_lock *);
193 void posix_test_lock(struct file *, struct file_lock *);
194 int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
195 int locks_delete_block(struct file_lock *);
196 int vfs_test_lock(struct file *, struct file_lock *);
197 int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
198 int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
199 bool vfs_inode_has_locks(struct inode *inode);
200 int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
201
202 void locks_init_lease(struct file_lease *);
203 void locks_free_lease(struct file_lease *fl);
204 struct file_lease *locks_alloc_lease(void);
205 int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
206 void lease_get_mtime(struct inode *, struct timespec64 *time);
207 int generic_setlease(struct file *, int, struct file_lease **, void **priv);
208 int kernel_setlease(struct file *, int, struct file_lease **, void **);
209 int vfs_setlease(struct file *, int, struct file_lease **, void **);
210 int lease_modify(struct file_lease *, int, struct list_head *);
211
212 struct notifier_block;
213 int lease_register_notifier(struct notifier_block *);
214 void lease_unregister_notifier(struct notifier_block *);
215
216 struct files_struct;
217 void show_fd_locks(struct seq_file *f,
218 struct file *filp, struct files_struct *files);
219 bool locks_owner_has_blockers(struct file_lock_context *flctx,
220 fl_owner_t owner);
221
222 static inline struct file_lock_context *
223 locks_inode_context(const struct inode *inode)
224 {
225 return smp_load_acquire(&inode->i_flctx);
226 }
227
228 #else /* !CONFIG_FILE_LOCKING */
229 static inline int fcntl_getlk(struct file *file, unsigned int cmd,
230 struct flock __user *user)
231 {
232 return -EINVAL;
233 }
234
235 static inline int fcntl_setlk(unsigned int fd, struct file *file,
236 unsigned int cmd, struct flock __user *user)
237 {
238 return -EACCES;
239 }
240
241 #if BITS_PER_LONG == 32
242 static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
243 struct flock64 *user)
244 {
245 return -EINVAL;
246 }
247
248 static inline int fcntl_setlk64(unsigned int fd, struct file *file,
249 unsigned int cmd, struct flock64 *user)
250 {
251 return -EACCES;
252 }
253 #endif
254 static inline int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
255 {
256 return -EINVAL;
257 }
258
259 static inline int fcntl_getlease(struct file *filp)
260 {
261 return F_UNLCK;
262 }
263
264 static inline bool lock_is_unlock(struct file_lock *fl)
265 {
266 return false;
267 }
268
269 static inline bool lock_is_read(struct file_lock *fl)
270 {
271 return false;
272 }
273
274 static inline bool lock_is_write(struct file_lock *fl)
275 {
276 return false;
277 }
278
279 static inline void locks_wake_up(struct file_lock *fl)
280 {
281 }
282
283 static inline void
284 locks_free_lock_context(struct inode *inode)
285 {
286 }
287
288 static inline void locks_init_lock(struct file_lock *fl)
289 {
290 return;
291 }
292
293 static inline void locks_init_lease(struct file_lease *fl)
294 {
295 return;
296 }
297
298 static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
299 {
300 return;
301 }
302
303 static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
304 {
305 return;
306 }
307
308 static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
309 {
310 return;
311 }
312
313 static inline void locks_remove_file(struct file *filp)
314 {
315 return;
316 }
317
318 static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
319 {
320 return;
321 }
322
323 static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
324 struct file_lock *conflock)
325 {
326 return -ENOLCK;
327 }
328
329 static inline int locks_delete_block(struct file_lock *waiter)
330 {
331 return -ENOENT;
332 }
333
334 static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
335 {
336 return 0;
337 }
338
339 static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
340 struct file_lock *fl, struct file_lock *conf)
341 {
342 return -ENOLCK;
343 }
344
345 static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
346 {
347 return 0;
348 }
349
350 static inline bool vfs_inode_has_locks(struct inode *inode)
351 {
352 return false;
353 }
354
355 static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
356 {
357 return -ENOLCK;
358 }
359
360 static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
361 {
362 return 0;
363 }
364
365 static inline void lease_get_mtime(struct inode *inode,
366 struct timespec64 *time)
367 {
368 return;
369 }
370
371 static inline int generic_setlease(struct file *filp, int arg,
372 struct file_lease **flp, void **priv)
373 {
374 return -EINVAL;
375 }
376
377 static inline int kernel_setlease(struct file *filp, int arg,
378 struct file_lease **lease, void **priv)
379 {
380 return -EINVAL;
381 }
382
383 static inline int vfs_setlease(struct file *filp, int arg,
384 struct file_lease **lease, void **priv)
385 {
386 return -EINVAL;
387 }
388
389 static inline int lease_modify(struct file_lease *fl, int arg,
390 struct list_head *dispose)
391 {
392 return -EINVAL;
393 }
394
395 struct files_struct;
396 static inline void show_fd_locks(struct seq_file *f,
397 struct file *filp, struct files_struct *files) {}
398 static inline bool locks_owner_has_blockers(struct file_lock_context *flctx,
399 fl_owner_t owner)
400 {
401 return false;
402 }
403
404 static inline struct file_lock_context *
405 locks_inode_context(const struct inode *inode)
406 {
407 return NULL;
408 }
409
410 #endif /* !CONFIG_FILE_LOCKING */
411
412 /* for walking lists of file_locks linked by fl_list */
413 #define for_each_file_lock(_fl, _head) list_for_each_entry(_fl, _head, c.flc_list)
414
415 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
416 {
417 return locks_lock_inode_wait(file_inode(filp), fl);
418 }
419
420 #ifdef CONFIG_FILE_LOCKING
421 static inline int break_lease(struct inode *inode, unsigned int mode)
422 {
423 /*
424 * Since this check is lockless, we must ensure that any refcounts
425 * taken are done before checking i_flctx->flc_lease. Otherwise, we
426 * could end up racing with tasks trying to set a new lease on this
427 * file.
428 */
429 smp_mb();
430 if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
431 return __break_lease(inode, mode, FL_LEASE);
432 return 0;
433 }
434
435 static inline int break_deleg(struct inode *inode, unsigned int mode)
436 {
437 /*
438 * Since this check is lockless, we must ensure that any refcounts
439 * taken are done before checking i_flctx->flc_lease. Otherwise, we
440 * could end up racing with tasks trying to set a new lease on this
441 * file.
442 */
443 smp_mb();
444 if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
445 return __break_lease(inode, mode, FL_DELEG);
446 return 0;
447 }
448
449 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
450 {
451 int ret;
452
453 ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
454 if (ret == -EWOULDBLOCK && delegated_inode) {
455 *delegated_inode = inode;
456 ihold(inode);
457 }
458 return ret;
459 }
460
461 static inline int break_deleg_wait(struct inode **delegated_inode)
462 {
463 int ret;
464
465 ret = break_deleg(*delegated_inode, O_WRONLY);
466 iput(*delegated_inode);
467 *delegated_inode = NULL;
468 return ret;
469 }
470
471 static inline int break_layout(struct inode *inode, bool wait)
472 {
473 smp_mb();
474 if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
475 return __break_lease(inode,
476 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
477 FL_LAYOUT);
478 return 0;
479 }
480
481 #else /* !CONFIG_FILE_LOCKING */
482 static inline int break_lease(struct inode *inode, unsigned int mode)
483 {
484 return 0;
485 }
486
487 static inline int break_deleg(struct inode *inode, unsigned int mode)
488 {
489 return 0;
490 }
491
492 static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
493 {
494 return 0;
495 }
496
497 static inline int break_deleg_wait(struct inode **delegated_inode)
498 {
499 BUG();
500 return 0;
501 }
502
503 static inline int break_layout(struct inode *inode, bool wait)
504 {
505 return 0;
506 }
507
508 #endif /* CONFIG_FILE_LOCKING */
509
510 #endif /* _LINUX_FILELOCK_H */
511
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