Line data Source code
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 :
31 : struct file_lock_operations {
32 : void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
33 : void (*fl_release_private)(struct file_lock *);
34 : };
35 :
36 : struct lock_manager_operations {
37 : void *lm_mod_owner;
38 : fl_owner_t (*lm_get_owner)(fl_owner_t);
39 : void (*lm_put_owner)(fl_owner_t);
40 : void (*lm_notify)(struct file_lock *); /* unblock callback */
41 : int (*lm_grant)(struct file_lock *, int);
42 : bool (*lm_break)(struct file_lock *);
43 : int (*lm_change)(struct file_lock *, int, struct list_head *);
44 : void (*lm_setup)(struct file_lock *, void **);
45 : bool (*lm_breaker_owns_lease)(struct file_lock *);
46 : bool (*lm_lock_expirable)(struct file_lock *cfl);
47 : void (*lm_expire_lock)(void);
48 : };
49 :
50 : struct lock_manager {
51 : struct list_head list;
52 : /*
53 : * NFSv4 and up also want opens blocked during the grace period;
54 : * NLM doesn't care:
55 : */
56 : bool block_opens;
57 : };
58 :
59 : struct net;
60 : void locks_start_grace(struct net *, struct lock_manager *);
61 : void locks_end_grace(struct lock_manager *);
62 : bool locks_in_grace(struct net *);
63 : bool opens_in_grace(struct net *);
64 :
65 : /*
66 : * struct file_lock has a union that some filesystems use to track
67 : * their own private info. The NFS side of things is defined here:
68 : */
69 : #include <linux/nfs_fs_i.h>
70 :
71 : /*
72 : * struct file_lock represents a generic "file lock". It's used to represent
73 : * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
74 : * note that the same struct is used to represent both a request for a lock and
75 : * the lock itself, but the same object is never used for both.
76 : *
77 : * FIXME: should we create a separate "struct lock_request" to help distinguish
78 : * these two uses?
79 : *
80 : * The varous i_flctx lists are ordered by:
81 : *
82 : * 1) lock owner
83 : * 2) lock range start
84 : * 3) lock range end
85 : *
86 : * Obviously, the last two criteria only matter for POSIX locks.
87 : */
88 : struct file_lock {
89 : struct file_lock *fl_blocker; /* The lock, that is blocking us */
90 : struct list_head fl_list; /* link into file_lock_context */
91 : struct hlist_node fl_link; /* node in global lists */
92 : struct list_head fl_blocked_requests; /* list of requests with
93 : * ->fl_blocker pointing here
94 : */
95 : struct list_head fl_blocked_member; /* node in
96 : * ->fl_blocker->fl_blocked_requests
97 : */
98 : fl_owner_t fl_owner;
99 : unsigned int fl_flags;
100 : unsigned char fl_type;
101 : unsigned int fl_pid;
102 : int fl_link_cpu; /* what cpu's list is this on? */
103 : wait_queue_head_t fl_wait;
104 : struct file *fl_file;
105 : loff_t fl_start;
106 : loff_t fl_end;
107 :
108 : struct fasync_struct * fl_fasync; /* for lease break notifications */
109 : /* for lease breaks: */
110 : unsigned long fl_break_time;
111 : unsigned long fl_downgrade_time;
112 :
113 : const struct file_lock_operations *fl_ops; /* Callbacks for filesystems */
114 : const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */
115 : union {
116 : struct nfs_lock_info nfs_fl;
117 : struct nfs4_lock_info nfs4_fl;
118 : struct {
119 : struct list_head link; /* link in AFS vnode's pending_locks list */
120 : int state; /* state of grant or error if -ve */
121 : unsigned int debug_id;
122 : } afs;
123 : struct {
124 : struct inode *inode;
125 : } ceph;
126 : } fl_u;
127 : } __randomize_layout;
128 :
129 : struct file_lock_context {
130 : spinlock_t flc_lock;
131 : struct list_head flc_flock;
132 : struct list_head flc_posix;
133 : struct list_head flc_lease;
134 : };
135 :
136 : #ifdef CONFIG_FILE_LOCKING
137 : int fcntl_getlk(struct file *, unsigned int, struct flock *);
138 : int fcntl_setlk(unsigned int, struct file *, unsigned int,
139 : struct flock *);
140 :
141 : #if BITS_PER_LONG == 32
142 : int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
143 : int fcntl_setlk64(unsigned int, struct file *, unsigned int,
144 : struct flock64 *);
145 : #endif
146 :
147 : int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
148 : int fcntl_getlease(struct file *filp);
149 :
150 : /* fs/locks.c */
151 : void locks_free_lock_context(struct inode *inode);
152 : void locks_free_lock(struct file_lock *fl);
153 : void locks_init_lock(struct file_lock *);
154 : struct file_lock * locks_alloc_lock(void);
155 : void locks_copy_lock(struct file_lock *, struct file_lock *);
156 : void locks_copy_conflock(struct file_lock *, struct file_lock *);
157 : void locks_remove_posix(struct file *, fl_owner_t);
158 : void locks_remove_file(struct file *);
159 : void locks_release_private(struct file_lock *);
160 : void posix_test_lock(struct file *, struct file_lock *);
161 : int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
162 : int locks_delete_block(struct file_lock *);
163 : int vfs_test_lock(struct file *, struct file_lock *);
164 : int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);
165 : int vfs_cancel_lock(struct file *filp, struct file_lock *fl);
166 : bool vfs_inode_has_locks(struct inode *inode);
167 : int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
168 : int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
169 : void lease_get_mtime(struct inode *, struct timespec64 *time);
170 : int generic_setlease(struct file *, long, struct file_lock **, void **priv);
171 : int vfs_setlease(struct file *, long, struct file_lock **, void **);
172 : int lease_modify(struct file_lock *, int, struct list_head *);
173 :
174 : struct notifier_block;
175 : int lease_register_notifier(struct notifier_block *);
176 : void lease_unregister_notifier(struct notifier_block *);
177 :
178 : struct files_struct;
179 : void show_fd_locks(struct seq_file *f,
180 : struct file *filp, struct files_struct *files);
181 : bool locks_owner_has_blockers(struct file_lock_context *flctx,
182 : fl_owner_t owner);
183 :
184 : static inline struct file_lock_context *
185 : locks_inode_context(const struct inode *inode)
186 : {
187 44 : return smp_load_acquire(&inode->i_flctx);
188 : }
189 :
190 : #else /* !CONFIG_FILE_LOCKING */
191 : static inline int fcntl_getlk(struct file *file, unsigned int cmd,
192 : struct flock __user *user)
193 : {
194 : return -EINVAL;
195 : }
196 :
197 : static inline int fcntl_setlk(unsigned int fd, struct file *file,
198 : unsigned int cmd, struct flock __user *user)
199 : {
200 : return -EACCES;
201 : }
202 :
203 : #if BITS_PER_LONG == 32
204 : static inline int fcntl_getlk64(struct file *file, unsigned int cmd,
205 : struct flock64 *user)
206 : {
207 : return -EINVAL;
208 : }
209 :
210 : static inline int fcntl_setlk64(unsigned int fd, struct file *file,
211 : unsigned int cmd, struct flock64 *user)
212 : {
213 : return -EACCES;
214 : }
215 : #endif
216 : static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
217 : {
218 : return -EINVAL;
219 : }
220 :
221 : static inline int fcntl_getlease(struct file *filp)
222 : {
223 : return F_UNLCK;
224 : }
225 :
226 : static inline void
227 : locks_free_lock_context(struct inode *inode)
228 : {
229 : }
230 :
231 : static inline void locks_init_lock(struct file_lock *fl)
232 : {
233 : return;
234 : }
235 :
236 : static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
237 : {
238 : return;
239 : }
240 :
241 : static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
242 : {
243 : return;
244 : }
245 :
246 : static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
247 : {
248 : return;
249 : }
250 :
251 : static inline void locks_remove_file(struct file *filp)
252 : {
253 : return;
254 : }
255 :
256 : static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
257 : {
258 : return;
259 : }
260 :
261 : static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
262 : struct file_lock *conflock)
263 : {
264 : return -ENOLCK;
265 : }
266 :
267 : static inline int locks_delete_block(struct file_lock *waiter)
268 : {
269 : return -ENOENT;
270 : }
271 :
272 : static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
273 : {
274 : return 0;
275 : }
276 :
277 : static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
278 : struct file_lock *fl, struct file_lock *conf)
279 : {
280 : return -ENOLCK;
281 : }
282 :
283 : static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
284 : {
285 : return 0;
286 : }
287 :
288 : static inline bool vfs_inode_has_locks(struct inode *inode)
289 : {
290 : return false;
291 : }
292 :
293 : static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
294 : {
295 : return -ENOLCK;
296 : }
297 :
298 : static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
299 : {
300 : return 0;
301 : }
302 :
303 : static inline void lease_get_mtime(struct inode *inode,
304 : struct timespec64 *time)
305 : {
306 : return;
307 : }
308 :
309 : static inline int generic_setlease(struct file *filp, long arg,
310 : struct file_lock **flp, void **priv)
311 : {
312 : return -EINVAL;
313 : }
314 :
315 : static inline int vfs_setlease(struct file *filp, long arg,
316 : struct file_lock **lease, void **priv)
317 : {
318 : return -EINVAL;
319 : }
320 :
321 : static inline int lease_modify(struct file_lock *fl, int arg,
322 : struct list_head *dispose)
323 : {
324 : return -EINVAL;
325 : }
326 :
327 : struct files_struct;
328 : static inline void show_fd_locks(struct seq_file *f,
329 : struct file *filp, struct files_struct *files) {}
330 : static inline bool locks_owner_has_blockers(struct file_lock_context *flctx,
331 : fl_owner_t owner)
332 : {
333 : return false;
334 : }
335 :
336 : static inline struct file_lock_context *
337 : locks_inode_context(const struct inode *inode)
338 : {
339 : return NULL;
340 : }
341 :
342 : #endif /* !CONFIG_FILE_LOCKING */
343 :
344 : static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
345 : {
346 0 : return locks_lock_inode_wait(file_inode(filp), fl);
347 : }
348 :
349 : #ifdef CONFIG_FILE_LOCKING
350 0 : static inline int break_lease(struct inode *inode, unsigned int mode)
351 : {
352 : /*
353 : * Since this check is lockless, we must ensure that any refcounts
354 : * taken are done before checking i_flctx->flc_lease. Otherwise, we
355 : * could end up racing with tasks trying to set a new lease on this
356 : * file.
357 : */
358 0 : smp_mb();
359 0 : if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
360 0 : return __break_lease(inode, mode, FL_LEASE);
361 : return 0;
362 : }
363 :
364 0 : static inline int break_deleg(struct inode *inode, unsigned int mode)
365 : {
366 : /*
367 : * Since this check is lockless, we must ensure that any refcounts
368 : * taken are done before checking i_flctx->flc_lease. Otherwise, we
369 : * could end up racing with tasks trying to set a new lease on this
370 : * file.
371 : */
372 0 : smp_mb();
373 0 : if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
374 0 : return __break_lease(inode, mode, FL_DELEG);
375 : return 0;
376 : }
377 :
378 0 : static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
379 : {
380 : int ret;
381 :
382 0 : ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
383 0 : if (ret == -EWOULDBLOCK && delegated_inode) {
384 0 : *delegated_inode = inode;
385 0 : ihold(inode);
386 : }
387 0 : return ret;
388 : }
389 :
390 0 : static inline int break_deleg_wait(struct inode **delegated_inode)
391 : {
392 : int ret;
393 :
394 0 : ret = break_deleg(*delegated_inode, O_WRONLY);
395 0 : iput(*delegated_inode);
396 0 : *delegated_inode = NULL;
397 0 : return ret;
398 : }
399 :
400 : static inline int break_layout(struct inode *inode, bool wait)
401 : {
402 : smp_mb();
403 : if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
404 : return __break_lease(inode,
405 : wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
406 : FL_LAYOUT);
407 : return 0;
408 : }
409 :
410 : #else /* !CONFIG_FILE_LOCKING */
411 : static inline int break_lease(struct inode *inode, unsigned int mode)
412 : {
413 : return 0;
414 : }
415 :
416 : static inline int break_deleg(struct inode *inode, unsigned int mode)
417 : {
418 : return 0;
419 : }
420 :
421 : static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode)
422 : {
423 : return 0;
424 : }
425 :
426 : static inline int break_deleg_wait(struct inode **delegated_inode)
427 : {
428 : BUG();
429 : return 0;
430 : }
431 :
432 : static inline int break_layout(struct inode *inode, bool wait)
433 : {
434 : return 0;
435 : }
436 :
437 : #endif /* CONFIG_FILE_LOCKING */
438 :
439 : #endif /* _LINUX_FILELOCK_H */
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