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
29struct file_lock;
30struct file_lease;
31
32struct file_lock_operations {
33 void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
34 void (*fl_release_private)(struct file_lock *);
35};
36
37struct 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
47struct 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
54struct 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
63struct net;
64void locks_start_grace(struct net *, struct lock_manager *);
65void locks_end_grace(struct lock_manager *);
66bool locks_in_grace(struct net *);
67bool 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
93struct 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
112struct 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
133struct 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
142struct 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
150int fcntl_getlk(struct file *, unsigned int, struct flock *);
151int fcntl_setlk(unsigned int, struct file *, unsigned int,
152 struct flock *);
153
154#if BITS_PER_LONG == 32
155int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
156int fcntl_setlk64(unsigned int, struct file *, unsigned int,
157 struct flock64 *);
158#endif
159
160int fcntl_setlease(unsigned int fd, struct file *filp, int arg);
161int fcntl_getlease(struct file *filp);
162
163static inline bool lock_is_unlock(struct file_lock *fl)
164{
165 return fl->c.flc_type == F_UNLCK;
166}
167
168static inline bool lock_is_read(struct file_lock *fl)
169{
170 return fl->c.flc_type == F_RDLCK;
171}
172
173static inline bool lock_is_write(struct file_lock *fl)
174{
175 return fl->c.flc_type == F_WRLCK;
176}
177
178static inline void locks_wake_up(struct file_lock *fl)
179{
180 wake_up(&fl->c.flc_wait);
181}
182
183static inline bool locks_can_async_lock(const struct file_operations *fops)
184{
185 return !fops->lock || fops->fop_flags & FOP_ASYNC_LOCK;
186}
187
188/* fs/locks.c */
189void locks_free_lock_context(struct inode *inode);
190void locks_free_lock(struct file_lock *fl);
191void locks_init_lock(struct file_lock *);
192struct file_lock *locks_alloc_lock(void);
193void locks_copy_lock(struct file_lock *, struct file_lock *);
194void locks_copy_conflock(struct file_lock *, struct file_lock *);
195void locks_remove_posix(struct file *, fl_owner_t);
196void locks_remove_file(struct file *);
197void locks_release_private(struct file_lock *);
198void posix_test_lock(struct file *, struct file_lock *);
199int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
200int locks_delete_block(struct file_lock *);
201int vfs_test_lock(struct file *, struct file_lock *);
202int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
203int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
204bool vfs_inode_has_locks(struct inode *inode);
205int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
206
207void locks_init_lease(struct file_lease *);
208void locks_free_lease(struct file_lease *fl);
209struct file_lease *locks_alloc_lease(void);
210int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
211void lease_get_mtime(struct inode *, struct timespec64 *time);
212int generic_setlease(struct file *, int, struct file_lease **, void **priv);
213int kernel_setlease(struct file *, int, struct file_lease **, void **);
214int vfs_setlease(struct file *, int, struct file_lease **, void **);
215int lease_modify(struct file_lease *, int, struct list_head *);
216
217struct notifier_block;
218int lease_register_notifier(struct notifier_block *);
219void lease_unregister_notifier(struct notifier_block *);
220
221struct files_struct;
222void show_fd_locks(struct seq_file *f,
223 struct file *filp, struct files_struct *files);
224bool locks_owner_has_blockers(struct file_lock_context *flctx,
225 fl_owner_t owner);
226
227static inline struct file_lock_context *
228locks_inode_context(const struct inode *inode)
229{
230 return smp_load_acquire(&inode->i_flctx);
231}
232
233#else /* !CONFIG_FILE_LOCKING */
234static inline int fcntl_getlk(struct file *file, unsigned int cmd,
235 struct flock __user *user)
236{
237 return -EINVAL;
238}
239
240static inline int fcntl_setlk(unsigned int fd, struct file *file,
241 unsigned int cmd, struct flock __user *user)
242{
243 return -EACCES;
244}
245
246#if BITS_PER_LONG == 32
247static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
248 struct flock64 *user)
249{
250 return -EINVAL;
251}
252
253static inline int fcntl_setlk64(unsigned int fd, struct file *file,
254 unsigned int cmd, struct flock64 *user)
255{
256 return -EACCES;
257}
258#endif
259static inline int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
260{
261 return -EINVAL;
262}
263
264static inline int fcntl_getlease(struct file *filp)
265{
266 return F_UNLCK;
267}
268
269static inline bool lock_is_unlock(struct file_lock *fl)
270{
271 return false;
272}
273
274static inline bool lock_is_read(struct file_lock *fl)
275{
276 return false;
277}
278
279static inline bool lock_is_write(struct file_lock *fl)
280{
281 return false;
282}
283
284static inline void locks_wake_up(struct file_lock *fl)
285{
286}
287
288static inline void
289locks_free_lock_context(struct inode *inode)
290{
291}
292
293static inline void locks_init_lock(struct file_lock *fl)
294{
295 return;
296}
297
298static inline void locks_init_lease(struct file_lease *fl)
299{
300 return;
301}
302
303static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
304{
305 return;
306}
307
308static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
309{
310 return;
311}
312
313static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
314{
315 return;
316}
317
318static inline void locks_remove_file(struct file *filp)
319{
320 return;
321}
322
323static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
324{
325 return;
326}
327
328static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
329 struct file_lock *conflock)
330{
331 return -ENOLCK;
332}
333
334static inline int locks_delete_block(struct file_lock *waiter)
335{
336 return -ENOENT;
337}
338
339static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
340{
341 return 0;
342}
343
344static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
345 struct file_lock *fl, struct file_lock *conf)
346{
347 return -ENOLCK;
348}
349
350static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
351{
352 return 0;
353}
354
355static inline bool vfs_inode_has_locks(struct inode *inode)
356{
357 return false;
358}
359
360static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
361{
362 return -ENOLCK;
363}
364
365static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
366{
367 return 0;
368}
369
370static inline void lease_get_mtime(struct inode *inode,
371 struct timespec64 *time)
372{
373 return;
374}
375
376static inline int generic_setlease(struct file *filp, int arg,
377 struct file_lease **flp, void **priv)
378{
379 return -EINVAL;
380}
381
382static inline int kernel_setlease(struct file *filp, int arg,
383 struct file_lease **lease, void **priv)
384{
385 return -EINVAL;
386}
387
388static inline int vfs_setlease(struct file *filp, int arg,
389 struct file_lease **lease, void **priv)
390{
391 return -EINVAL;
392}
393
394static inline int lease_modify(struct file_lease *fl, int arg,
395 struct list_head *dispose)
396{
397 return -EINVAL;
398}
399
400struct files_struct;
401static inline void show_fd_locks(struct seq_file *f,
402 struct file *filp, struct files_struct *files) {}
403static inline bool locks_owner_has_blockers(struct file_lock_context *flctx,
404 fl_owner_t owner)
405{
406 return false;
407}
408
409static inline struct file_lock_context *
410locks_inode_context(const struct inode *inode)
411{
412 return NULL;
413}
414
415#endif /* !CONFIG_FILE_LOCKING */
416
417/* for walking lists of file_locks linked by fl_list */
418#define for_each_file_lock(_fl, _head) list_for_each_entry(_fl, _head, c.flc_list)
419
420static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
421{
422 return locks_lock_inode_wait(inode: file_inode(f: filp), fl);
423}
424
425#ifdef CONFIG_FILE_LOCKING
426static inline int break_lease(struct inode *inode, unsigned int mode)
427{
428 struct file_lock_context *flctx;
429
430 /*
431 * Since this check is lockless, we must ensure that any refcounts
432 * taken are done before checking i_flctx->flc_lease. Otherwise, we
433 * could end up racing with tasks trying to set a new lease on this
434 * file.
435 */
436 flctx = READ_ONCE(inode->i_flctx);
437 if (!flctx)
438 return 0;
439 smp_mb();
440 if (!list_empty_careful(head: &flctx->flc_lease))
441 return __break_lease(inode, flags: mode, FL_LEASE);
442 return 0;
443}
444
445static inline int break_deleg(struct inode *inode, unsigned int mode)
446{
447 struct file_lock_context *flctx;
448
449 /*
450 * Since this check is lockless, we must ensure that any refcounts
451 * taken are done before checking i_flctx->flc_lease. Otherwise, we
452 * could end up racing with tasks trying to set a new lease on this
453 * file.
454 */
455 flctx = READ_ONCE(inode->i_flctx);
456 if (!flctx)
457 return 0;
458 smp_mb();
459 if (!list_empty_careful(head: &flctx->flc_lease))
460 return __break_lease(inode, flags: mode, FL_DELEG);
461 return 0;
462}
463
464static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
465{
466 int ret;
467
468 ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
469 if (ret == -EWOULDBLOCK && delegated_inode) {
470 *delegated_inode = inode;
471 ihold(inode);
472 }
473 return ret;
474}
475
476static inline int break_deleg_wait(struct inode **delegated_inode)
477{
478 int ret;
479
480 ret = break_deleg(inode: *delegated_inode, O_WRONLY);
481 iput(*delegated_inode);
482 *delegated_inode = NULL;
483 return ret;
484}
485
486static inline int break_layout(struct inode *inode, bool wait)
487{
488 smp_mb();
489 if (inode->i_flctx && !list_empty_careful(head: &inode->i_flctx->flc_lease))
490 return __break_lease(inode,
491 flags: wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
492 FL_LAYOUT);
493 return 0;
494}
495
496#else /* !CONFIG_FILE_LOCKING */
497static inline int break_lease(struct inode *inode, unsigned int mode)
498{
499 return 0;
500}
501
502static inline int break_deleg(struct inode *inode, unsigned int mode)
503{
504 return 0;
505}
506
507static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
508{
509 return 0;
510}
511
512static inline int break_deleg_wait(struct inode **delegated_inode)
513{
514 BUG();
515 return 0;
516}
517
518static inline int break_layout(struct inode *inode, bool wait)
519{
520 return 0;
521}
522
523#endif /* CONFIG_FILE_LOCKING */
524
525#endif /* _LINUX_FILELOCK_H */
526

source code of linux/include/linux/filelock.h

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