Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * linux/fs/locks.c
4 : *
5 : * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
6 : * Doug Evans (dje@spiff.uucp), August 07, 1992
7 : *
8 : * Deadlock detection added.
9 : * FIXME: one thing isn't handled yet:
10 : * - mandatory locks (requires lots of changes elsewhere)
11 : * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
12 : *
13 : * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
14 : * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
15 : *
16 : * Converted file_lock_table to a linked list from an array, which eliminates
17 : * the limits on how many active file locks are open.
18 : * Chad Page (pageone@netcom.com), November 27, 1994
19 : *
20 : * Removed dependency on file descriptors. dup()'ed file descriptors now
21 : * get the same locks as the original file descriptors, and a close() on
22 : * any file descriptor removes ALL the locks on the file for the current
23 : * process. Since locks still depend on the process id, locks are inherited
24 : * after an exec() but not after a fork(). This agrees with POSIX, and both
25 : * BSD and SVR4 practice.
26 : * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
27 : *
28 : * Scrapped free list which is redundant now that we allocate locks
29 : * dynamically with kmalloc()/kfree().
30 : * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
31 : *
32 : * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
33 : *
34 : * FL_POSIX locks are created with calls to fcntl() and lockf() through the
35 : * fcntl() system call. They have the semantics described above.
36 : *
37 : * FL_FLOCK locks are created with calls to flock(), through the flock()
38 : * system call, which is new. Old C libraries implement flock() via fcntl()
39 : * and will continue to use the old, broken implementation.
40 : *
41 : * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
42 : * with a file pointer (filp). As a result they can be shared by a parent
43 : * process and its children after a fork(). They are removed when the last
44 : * file descriptor referring to the file pointer is closed (unless explicitly
45 : * unlocked).
46 : *
47 : * FL_FLOCK locks never deadlock, an existing lock is always removed before
48 : * upgrading from shared to exclusive (or vice versa). When this happens
49 : * any processes blocked by the current lock are woken up and allowed to
50 : * run before the new lock is applied.
51 : * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
52 : *
53 : * Removed some race conditions in flock_lock_file(), marked other possible
54 : * races. Just grep for FIXME to see them.
55 : * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
56 : *
57 : * Addressed Dmitry's concerns. Deadlock checking no longer recursive.
58 : * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
59 : * once we've checked for blocking and deadlocking.
60 : * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
61 : *
62 : * Initial implementation of mandatory locks. SunOS turned out to be
63 : * a rotten model, so I implemented the "obvious" semantics.
64 : * See 'Documentation/filesystems/mandatory-locking.rst' for details.
65 : * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
66 : *
67 : * Don't allow mandatory locks on mmap()'ed files. Added simple functions to
68 : * check if a file has mandatory locks, used by mmap(), open() and creat() to
69 : * see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
70 : * Manual, Section 2.
71 : * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
72 : *
73 : * Tidied up block list handling. Added '/proc/locks' interface.
74 : * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
75 : *
76 : * Fixed deadlock condition for pathological code that mixes calls to
77 : * flock() and fcntl().
78 : * Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
79 : *
80 : * Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
81 : * for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
82 : * guarantee sensible behaviour in the case where file system modules might
83 : * be compiled with different options than the kernel itself.
84 : * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
85 : *
86 : * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
87 : * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
88 : * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
89 : *
90 : * Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
91 : * locks. Changed process synchronisation to avoid dereferencing locks that
92 : * have already been freed.
93 : * Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
94 : *
95 : * Made the block list a circular list to minimise searching in the list.
96 : * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
97 : *
98 : * Made mandatory locking a mount option. Default is not to allow mandatory
99 : * locking.
100 : * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
101 : *
102 : * Some adaptations for NFS support.
103 : * Olaf Kirch (okir@monad.swb.de), Dec 1996,
104 : *
105 : * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
106 : * Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
107 : *
108 : * Use slab allocator instead of kmalloc/kfree.
109 : * Use generic list implementation from <linux/list.h>.
110 : * Sped up posix_locks_deadlock by only considering blocked locks.
111 : * Matthew Wilcox <willy@debian.org>, March, 2000.
112 : *
113 : * Leases and LOCK_MAND
114 : * Matthew Wilcox <willy@debian.org>, June, 2000.
115 : * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
116 : *
117 : * Locking conflicts and dependencies:
118 : * If multiple threads attempt to lock the same byte (or flock the same file)
119 : * only one can be granted the lock, and other must wait their turn.
120 : * The first lock has been "applied" or "granted", the others are "waiting"
121 : * and are "blocked" by the "applied" lock..
122 : *
123 : * Waiting and applied locks are all kept in trees whose properties are:
124 : *
125 : * - the root of a tree may be an applied or waiting lock.
126 : * - every other node in the tree is a waiting lock that
127 : * conflicts with every ancestor of that node.
128 : *
129 : * Every such tree begins life as a waiting singleton which obviously
130 : * satisfies the above properties.
131 : *
132 : * The only ways we modify trees preserve these properties:
133 : *
134 : * 1. We may add a new leaf node, but only after first verifying that it
135 : * conflicts with all of its ancestors.
136 : * 2. We may remove the root of a tree, creating a new singleton
137 : * tree from the root and N new trees rooted in the immediate
138 : * children.
139 : * 3. If the root of a tree is not currently an applied lock, we may
140 : * apply it (if possible).
141 : * 4. We may upgrade the root of the tree (either extend its range,
142 : * or upgrade its entire range from read to write).
143 : *
144 : * When an applied lock is modified in a way that reduces or downgrades any
145 : * part of its range, we remove all its children (2 above). This particularly
146 : * happens when a lock is unlocked.
147 : *
148 : * For each of those child trees we "wake up" the thread which is
149 : * waiting for the lock so it can continue handling as follows: if the
150 : * root of the tree applies, we do so (3). If it doesn't, it must
151 : * conflict with some applied lock. We remove (wake up) all of its children
152 : * (2), and add it is a new leaf to the tree rooted in the applied
153 : * lock (1). We then repeat the process recursively with those
154 : * children.
155 : *
156 : */
157 :
158 : #include <linux/capability.h>
159 : #include <linux/file.h>
160 : #include <linux/fdtable.h>
161 : #include <linux/fs.h>
162 : #include <linux/init.h>
163 : #include <linux/security.h>
164 : #include <linux/slab.h>
165 : #include <linux/syscalls.h>
166 : #include <linux/time.h>
167 : #include <linux/rcupdate.h>
168 : #include <linux/pid_namespace.h>
169 : #include <linux/hashtable.h>
170 : #include <linux/percpu.h>
171 :
172 : #define CREATE_TRACE_POINTS
173 : #include <trace/events/filelock.h>
174 :
175 : #include <linux/uaccess.h>
176 :
177 : #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
178 : #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
179 : #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
180 : #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
181 : #define IS_REMOTELCK(fl) (fl->fl_pid <= 0)
182 :
183 0 : static bool lease_breaking(struct file_lock *fl)
184 : {
185 0 : return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
186 : }
187 :
188 0 : static int target_leasetype(struct file_lock *fl)
189 : {
190 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
191 : return F_UNLCK;
192 0 : if (fl->fl_flags & FL_DOWNGRADE_PENDING)
193 : return F_RDLCK;
194 0 : return fl->fl_type;
195 : }
196 :
197 : int leases_enable = 1;
198 : int lease_break_time = 45;
199 :
200 : /*
201 : * The global file_lock_list is only used for displaying /proc/locks, so we
202 : * keep a list on each CPU, with each list protected by its own spinlock.
203 : * Global serialization is done using file_rwsem.
204 : *
205 : * Note that alterations to the list also require that the relevant flc_lock is
206 : * held.
207 : */
208 : struct file_lock_list_struct {
209 : spinlock_t lock;
210 : struct hlist_head hlist;
211 : };
212 : static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
213 : DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
214 :
215 :
216 : /*
217 : * The blocked_hash is used to find POSIX lock loops for deadlock detection.
218 : * It is protected by blocked_lock_lock.
219 : *
220 : * We hash locks by lockowner in order to optimize searching for the lock a
221 : * particular lockowner is waiting on.
222 : *
223 : * FIXME: make this value scale via some heuristic? We generally will want more
224 : * buckets when we have more lockowners holding locks, but that's a little
225 : * difficult to determine without knowing what the workload will look like.
226 : */
227 : #define BLOCKED_HASH_BITS 7
228 : static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
229 :
230 : /*
231 : * This lock protects the blocked_hash. Generally, if you're accessing it, you
232 : * want to be holding this lock.
233 : *
234 : * In addition, it also protects the fl->fl_blocked_requests list, and the
235 : * fl->fl_blocker pointer for file_lock structures that are acting as lock
236 : * requests (in contrast to those that are acting as records of acquired locks).
237 : *
238 : * Note that when we acquire this lock in order to change the above fields,
239 : * we often hold the flc_lock as well. In certain cases, when reading the fields
240 : * protected by this lock, we can skip acquiring it iff we already hold the
241 : * flc_lock.
242 : */
243 : static DEFINE_SPINLOCK(blocked_lock_lock);
244 :
245 : static struct kmem_cache *flctx_cache __read_mostly;
246 : static struct kmem_cache *filelock_cache __read_mostly;
247 :
248 : static struct file_lock_context *
249 361 : locks_get_lock_context(struct inode *inode, int type)
250 : {
251 361 : struct file_lock_context *ctx;
252 :
253 : /* paired with cmpxchg() below */
254 361 : ctx = smp_load_acquire(&inode->i_flctx);
255 361 : if (likely(ctx) || type == F_UNLCK)
256 242 : goto out;
257 :
258 119 : ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
259 119 : if (!ctx)
260 0 : goto out;
261 :
262 119 : spin_lock_init(&ctx->flc_lock);
263 119 : INIT_LIST_HEAD(&ctx->flc_flock);
264 119 : INIT_LIST_HEAD(&ctx->flc_posix);
265 119 : INIT_LIST_HEAD(&ctx->flc_lease);
266 :
267 : /*
268 : * Assign the pointer if it's not already assigned. If it is, then
269 : * free the context we just allocated.
270 : */
271 119 : if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
272 0 : kmem_cache_free(flctx_cache, ctx);
273 0 : ctx = smp_load_acquire(&inode->i_flctx);
274 : }
275 119 : out:
276 361 : trace_locks_get_lock_context(inode, type, ctx);
277 361 : return ctx;
278 : }
279 :
280 : static void
281 0 : locks_dump_ctx_list(struct list_head *list, char *list_type)
282 : {
283 0 : struct file_lock *fl;
284 :
285 0 : list_for_each_entry(fl, list, fl_list) {
286 0 : pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
287 : }
288 0 : }
289 :
290 : static void
291 58 : locks_check_ctx_lists(struct inode *inode)
292 : {
293 58 : struct file_lock_context *ctx = inode->i_flctx;
294 :
295 58 : if (unlikely(!list_empty(&ctx->flc_flock) ||
296 : !list_empty(&ctx->flc_posix) ||
297 : !list_empty(&ctx->flc_lease))) {
298 0 : pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
299 : MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
300 : inode->i_ino);
301 0 : locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
302 0 : locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
303 0 : locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
304 : }
305 58 : }
306 :
307 : static void
308 534 : locks_check_ctx_file_list(struct file *filp, struct list_head *list,
309 : char *list_type)
310 : {
311 534 : struct file_lock *fl;
312 534 : struct inode *inode = locks_inode(filp);
313 :
314 571 : list_for_each_entry(fl, list, fl_list)
315 37 : if (fl->fl_file == filp)
316 0 : pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%lx "
317 : " fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
318 : list_type, MAJOR(inode->i_sb->s_dev),
319 : MINOR(inode->i_sb->s_dev), inode->i_ino,
320 : fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
321 534 : }
322 :
323 : void
324 5292 : locks_free_lock_context(struct inode *inode)
325 : {
326 5292 : struct file_lock_context *ctx = inode->i_flctx;
327 :
328 5292 : if (unlikely(ctx)) {
329 58 : locks_check_ctx_lists(inode);
330 58 : kmem_cache_free(flctx_cache, ctx);
331 : }
332 5292 : }
333 :
334 577 : static void locks_init_lock_heads(struct file_lock *fl)
335 : {
336 577 : INIT_HLIST_NODE(&fl->fl_link);
337 577 : INIT_LIST_HEAD(&fl->fl_list);
338 577 : INIT_LIST_HEAD(&fl->fl_blocked_requests);
339 577 : INIT_LIST_HEAD(&fl->fl_blocked_member);
340 577 : init_waitqueue_head(&fl->fl_wait);
341 577 : }
342 :
343 : /* Allocate an empty lock structure. */
344 458 : struct file_lock *locks_alloc_lock(void)
345 : {
346 458 : struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
347 :
348 458 : if (fl)
349 458 : locks_init_lock_heads(fl);
350 :
351 458 : return fl;
352 : }
353 : EXPORT_SYMBOL_GPL(locks_alloc_lock);
354 :
355 453 : void locks_release_private(struct file_lock *fl)
356 : {
357 453 : BUG_ON(waitqueue_active(&fl->fl_wait));
358 453 : BUG_ON(!list_empty(&fl->fl_list));
359 453 : BUG_ON(!list_empty(&fl->fl_blocked_requests));
360 453 : BUG_ON(!list_empty(&fl->fl_blocked_member));
361 453 : BUG_ON(!hlist_unhashed(&fl->fl_link));
362 :
363 453 : if (fl->fl_ops) {
364 0 : if (fl->fl_ops->fl_release_private)
365 0 : fl->fl_ops->fl_release_private(fl);
366 0 : fl->fl_ops = NULL;
367 : }
368 :
369 453 : if (fl->fl_lmops) {
370 0 : if (fl->fl_lmops->lm_put_owner) {
371 0 : fl->fl_lmops->lm_put_owner(fl->fl_owner);
372 0 : fl->fl_owner = NULL;
373 : }
374 0 : fl->fl_lmops = NULL;
375 : }
376 453 : }
377 : EXPORT_SYMBOL_GPL(locks_release_private);
378 :
379 : /* Free a lock which is not in use. */
380 453 : void locks_free_lock(struct file_lock *fl)
381 : {
382 453 : locks_release_private(fl);
383 453 : kmem_cache_free(filelock_cache, fl);
384 453 : }
385 : EXPORT_SYMBOL(locks_free_lock);
386 :
387 : static void
388 361 : locks_dispose_list(struct list_head *dispose)
389 : {
390 361 : struct file_lock *fl;
391 :
392 511 : while (!list_empty(dispose)) {
393 150 : fl = list_first_entry(dispose, struct file_lock, fl_list);
394 150 : list_del_init(&fl->fl_list);
395 150 : locks_free_lock(fl);
396 : }
397 361 : }
398 :
399 119 : void locks_init_lock(struct file_lock *fl)
400 : {
401 119 : memset(fl, 0, sizeof(struct file_lock));
402 119 : locks_init_lock_heads(fl);
403 119 : }
404 : EXPORT_SYMBOL(locks_init_lock);
405 :
406 : /*
407 : * Initialize a new lock from an existing file_lock structure.
408 : */
409 155 : void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
410 : {
411 155 : new->fl_owner = fl->fl_owner;
412 155 : new->fl_pid = fl->fl_pid;
413 155 : new->fl_file = NULL;
414 155 : new->fl_flags = fl->fl_flags;
415 155 : new->fl_type = fl->fl_type;
416 155 : new->fl_start = fl->fl_start;
417 155 : new->fl_end = fl->fl_end;
418 155 : new->fl_lmops = fl->fl_lmops;
419 155 : new->fl_ops = NULL;
420 :
421 155 : if (fl->fl_lmops) {
422 0 : if (fl->fl_lmops->lm_get_owner)
423 0 : fl->fl_lmops->lm_get_owner(fl->fl_owner);
424 : }
425 155 : }
426 : EXPORT_SYMBOL(locks_copy_conflock);
427 :
428 155 : void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
429 : {
430 : /* "new" must be a freshly-initialized lock */
431 155 : WARN_ON_ONCE(new->fl_ops);
432 :
433 155 : locks_copy_conflock(new, fl);
434 :
435 155 : new->fl_file = fl->fl_file;
436 155 : new->fl_ops = fl->fl_ops;
437 :
438 155 : if (fl->fl_ops) {
439 0 : if (fl->fl_ops->fl_copy_lock)
440 0 : fl->fl_ops->fl_copy_lock(new, fl);
441 : }
442 155 : }
443 : EXPORT_SYMBOL(locks_copy_lock);
444 :
445 155 : static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
446 : {
447 155 : struct file_lock *f;
448 :
449 : /*
450 : * As ctx->flc_lock is held, new requests cannot be added to
451 : * ->fl_blocked_requests, so we don't need a lock to check if it
452 : * is empty.
453 : */
454 155 : if (list_empty(&fl->fl_blocked_requests))
455 : return;
456 0 : spin_lock(&blocked_lock_lock);
457 0 : list_splice_init(&fl->fl_blocked_requests, &new->fl_blocked_requests);
458 0 : list_for_each_entry(f, &new->fl_blocked_requests, fl_blocked_member)
459 0 : f->fl_blocker = new;
460 0 : spin_unlock(&blocked_lock_lock);
461 : }
462 :
463 227 : static inline int flock_translate_cmd(int cmd) {
464 227 : if (cmd & LOCK_MAND)
465 0 : return cmd & (LOCK_MAND | LOCK_RW);
466 227 : switch (cmd) {
467 : case LOCK_SH:
468 : return F_RDLCK;
469 : case LOCK_EX:
470 : return F_WRLCK;
471 : case LOCK_UN:
472 : return F_UNLCK;
473 : }
474 : return -EINVAL;
475 : }
476 :
477 : /* Fill in a file_lock structure with an appropriate FLOCK lock. */
478 : static struct file_lock *
479 227 : flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
480 : {
481 227 : int type = flock_translate_cmd(cmd);
482 :
483 227 : if (type < 0)
484 0 : return ERR_PTR(type);
485 :
486 227 : if (fl == NULL) {
487 150 : fl = locks_alloc_lock();
488 150 : if (fl == NULL)
489 227 : return ERR_PTR(-ENOMEM);
490 : } else {
491 77 : locks_init_lock(fl);
492 : }
493 :
494 227 : fl->fl_file = filp;
495 227 : fl->fl_owner = filp;
496 227 : fl->fl_pid = current->tgid;
497 227 : fl->fl_flags = FL_FLOCK;
498 227 : fl->fl_type = type;
499 227 : fl->fl_end = OFFSET_MAX;
500 :
501 227 : return fl;
502 : }
503 :
504 90 : static int assign_type(struct file_lock *fl, long type)
505 : {
506 90 : switch (type) {
507 90 : case F_RDLCK:
508 : case F_WRLCK:
509 : case F_UNLCK:
510 90 : fl->fl_type = type;
511 90 : break;
512 : default:
513 : return -EINVAL;
514 : }
515 90 : return 0;
516 : }
517 :
518 90 : static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
519 : struct flock64 *l)
520 : {
521 90 : switch (l->l_whence) {
522 90 : case SEEK_SET:
523 90 : fl->fl_start = 0;
524 90 : break;
525 0 : case SEEK_CUR:
526 0 : fl->fl_start = filp->f_pos;
527 0 : break;
528 : case SEEK_END:
529 0 : fl->fl_start = i_size_read(file_inode(filp));
530 0 : break;
531 : default:
532 : return -EINVAL;
533 : }
534 90 : if (l->l_start > OFFSET_MAX - fl->fl_start)
535 : return -EOVERFLOW;
536 90 : fl->fl_start += l->l_start;
537 90 : if (fl->fl_start < 0)
538 : return -EINVAL;
539 :
540 : /* POSIX-1996 leaves the case l->l_len < 0 undefined;
541 : POSIX-2001 defines it. */
542 90 : if (l->l_len > 0) {
543 0 : if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
544 : return -EOVERFLOW;
545 0 : fl->fl_end = fl->fl_start + (l->l_len - 1);
546 :
547 90 : } else if (l->l_len < 0) {
548 0 : if (fl->fl_start + l->l_len < 0)
549 : return -EINVAL;
550 0 : fl->fl_end = fl->fl_start - 1;
551 0 : fl->fl_start += l->l_len;
552 : } else
553 90 : fl->fl_end = OFFSET_MAX;
554 :
555 90 : fl->fl_owner = current->files;
556 90 : fl->fl_pid = current->tgid;
557 90 : fl->fl_file = filp;
558 90 : fl->fl_flags = FL_POSIX;
559 90 : fl->fl_ops = NULL;
560 90 : fl->fl_lmops = NULL;
561 :
562 90 : return assign_type(fl, l->l_type);
563 : }
564 :
565 : /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
566 : * style lock.
567 : */
568 90 : static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
569 : struct flock *l)
570 : {
571 90 : struct flock64 ll = {
572 90 : .l_type = l->l_type,
573 90 : .l_whence = l->l_whence,
574 90 : .l_start = l->l_start,
575 90 : .l_len = l->l_len,
576 : };
577 :
578 90 : return flock64_to_posix_lock(filp, fl, &ll);
579 : }
580 :
581 : /* default lease lock manager operations */
582 : static bool
583 0 : lease_break_callback(struct file_lock *fl)
584 : {
585 0 : kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
586 0 : return false;
587 : }
588 :
589 : static void
590 0 : lease_setup(struct file_lock *fl, void **priv)
591 : {
592 0 : struct file *filp = fl->fl_file;
593 0 : struct fasync_struct *fa = *priv;
594 :
595 : /*
596 : * fasync_insert_entry() returns the old entry if any. If there was no
597 : * old entry, then it used "priv" and inserted it into the fasync list.
598 : * Clear the pointer to indicate that it shouldn't be freed.
599 : */
600 0 : if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
601 0 : *priv = NULL;
602 :
603 0 : __f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
604 0 : }
605 :
606 : static const struct lock_manager_operations lease_manager_ops = {
607 : .lm_break = lease_break_callback,
608 : .lm_change = lease_modify,
609 : .lm_setup = lease_setup,
610 : };
611 :
612 : /*
613 : * Initialize a lease, use the default lock manager operations
614 : */
615 0 : static int lease_init(struct file *filp, long type, struct file_lock *fl)
616 : {
617 0 : if (assign_type(fl, type) != 0)
618 : return -EINVAL;
619 :
620 0 : fl->fl_owner = filp;
621 0 : fl->fl_pid = current->tgid;
622 :
623 0 : fl->fl_file = filp;
624 0 : fl->fl_flags = FL_LEASE;
625 0 : fl->fl_start = 0;
626 0 : fl->fl_end = OFFSET_MAX;
627 0 : fl->fl_ops = NULL;
628 0 : fl->fl_lmops = &lease_manager_ops;
629 0 : return 0;
630 : }
631 :
632 : /* Allocate a file_lock initialised to this type of lease */
633 0 : static struct file_lock *lease_alloc(struct file *filp, long type)
634 : {
635 0 : struct file_lock *fl = locks_alloc_lock();
636 0 : int error = -ENOMEM;
637 :
638 0 : if (fl == NULL)
639 0 : return ERR_PTR(error);
640 :
641 0 : error = lease_init(filp, type, fl);
642 0 : if (error) {
643 0 : locks_free_lock(fl);
644 0 : return ERR_PTR(error);
645 : }
646 : return fl;
647 : }
648 :
649 : /* Check if two locks overlap each other.
650 : */
651 2 : static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
652 : {
653 4 : return ((fl1->fl_end >= fl2->fl_start) &&
654 2 : (fl2->fl_end >= fl1->fl_start));
655 : }
656 :
657 : /*
658 : * Check whether two locks have the same owner.
659 : */
660 131 : static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
661 : {
662 131 : return fl1->fl_owner == fl2->fl_owner;
663 : }
664 :
665 : /* Must be called with the flc_lock held! */
666 155 : static void locks_insert_global_locks(struct file_lock *fl)
667 : {
668 155 : struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
669 :
670 465 : percpu_rwsem_assert_held(&file_rwsem);
671 :
672 155 : spin_lock(&fll->lock);
673 155 : fl->fl_link_cpu = smp_processor_id();
674 155 : hlist_add_head(&fl->fl_link, &fll->hlist);
675 155 : spin_unlock(&fll->lock);
676 155 : }
677 :
678 : /* Must be called with the flc_lock held! */
679 150 : static void locks_delete_global_locks(struct file_lock *fl)
680 : {
681 150 : struct file_lock_list_struct *fll;
682 :
683 450 : percpu_rwsem_assert_held(&file_rwsem);
684 :
685 : /*
686 : * Avoid taking lock if already unhashed. This is safe since this check
687 : * is done while holding the flc_lock, and new insertions into the list
688 : * also require that it be held.
689 : */
690 150 : if (hlist_unhashed(&fl->fl_link))
691 : return;
692 :
693 150 : fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
694 150 : spin_lock(&fll->lock);
695 150 : hlist_del_init(&fl->fl_link);
696 150 : spin_unlock(&fll->lock);
697 : }
698 :
699 : static unsigned long
700 4 : posix_owner_key(struct file_lock *fl)
701 : {
702 4 : return (unsigned long)fl->fl_owner;
703 : }
704 :
705 2 : static void locks_insert_global_blocked(struct file_lock *waiter)
706 : {
707 6 : lockdep_assert_held(&blocked_lock_lock);
708 :
709 2 : hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
710 2 : }
711 :
712 2 : static void locks_delete_global_blocked(struct file_lock *waiter)
713 : {
714 6 : lockdep_assert_held(&blocked_lock_lock);
715 :
716 2 : hash_del(&waiter->fl_link);
717 2 : }
718 :
719 : /* Remove waiter from blocker's block list.
720 : * When blocker ends up pointing to itself then the list is empty.
721 : *
722 : * Must be called with blocked_lock_lock held.
723 : */
724 2 : static void __locks_delete_block(struct file_lock *waiter)
725 : {
726 2 : locks_delete_global_blocked(waiter);
727 2 : list_del_init(&waiter->fl_blocked_member);
728 2 : }
729 :
730 6 : static void __locks_wake_up_blocks(struct file_lock *blocker)
731 : {
732 6 : while (!list_empty(&blocker->fl_blocked_requests)) {
733 2 : struct file_lock *waiter;
734 :
735 2 : waiter = list_first_entry(&blocker->fl_blocked_requests,
736 : struct file_lock, fl_blocked_member);
737 2 : __locks_delete_block(waiter);
738 2 : if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
739 0 : waiter->fl_lmops->lm_notify(waiter);
740 : else
741 2 : wake_up(&waiter->fl_wait);
742 :
743 : /*
744 : * The setting of fl_blocker to NULL marks the "done"
745 : * point in deleting a block. Paired with acquire at the top
746 : * of locks_delete_block().
747 : */
748 8 : smp_store_release(&waiter->fl_blocker, NULL);
749 : }
750 6 : }
751 :
752 : /**
753 : * locks_delete_block - stop waiting for a file lock
754 : * @waiter: the lock which was waiting
755 : *
756 : * lockd/nfsd need to disconnect the lock while working on it.
757 : */
758 240 : int locks_delete_block(struct file_lock *waiter)
759 : {
760 240 : int status = -ENOENT;
761 :
762 : /*
763 : * If fl_blocker is NULL, it won't be set again as this thread "owns"
764 : * the lock and is the only one that might try to claim the lock.
765 : *
766 : * We use acquire/release to manage fl_blocker so that we can
767 : * optimize away taking the blocked_lock_lock in many cases.
768 : *
769 : * The smp_load_acquire guarantees two things:
770 : *
771 : * 1/ that fl_blocked_requests can be tested locklessly. If something
772 : * was recently added to that list it must have been in a locked region
773 : * *before* the locked region when fl_blocker was set to NULL.
774 : *
775 : * 2/ that no other thread is accessing 'waiter', so it is safe to free
776 : * it. __locks_wake_up_blocks is careful not to touch waiter after
777 : * fl_blocker is released.
778 : *
779 : * If a lockless check of fl_blocker shows it to be NULL, we know that
780 : * no new locks can be inserted into its fl_blocked_requests list, and
781 : * can avoid doing anything further if the list is empty.
782 : */
783 240 : if (!smp_load_acquire(&waiter->fl_blocker) &&
784 240 : list_empty(&waiter->fl_blocked_requests))
785 : return status;
786 :
787 0 : spin_lock(&blocked_lock_lock);
788 0 : if (waiter->fl_blocker)
789 0 : status = 0;
790 0 : __locks_wake_up_blocks(waiter);
791 0 : __locks_delete_block(waiter);
792 :
793 : /*
794 : * The setting of fl_blocker to NULL marks the "done" point in deleting
795 : * a block. Paired with acquire at the top of this function.
796 : */
797 0 : smp_store_release(&waiter->fl_blocker, NULL);
798 0 : spin_unlock(&blocked_lock_lock);
799 0 : return status;
800 : }
801 : EXPORT_SYMBOL(locks_delete_block);
802 :
803 : /* Insert waiter into blocker's block list.
804 : * We use a circular list so that processes can be easily woken up in
805 : * the order they blocked. The documentation doesn't require this but
806 : * it seems like the reasonable thing to do.
807 : *
808 : * Must be called with both the flc_lock and blocked_lock_lock held. The
809 : * fl_blocked_requests list itself is protected by the blocked_lock_lock,
810 : * but by ensuring that the flc_lock is also held on insertions we can avoid
811 : * taking the blocked_lock_lock in some cases when we see that the
812 : * fl_blocked_requests list is empty.
813 : *
814 : * Rather than just adding to the list, we check for conflicts with any existing
815 : * waiters, and add beneath any waiter that blocks the new waiter.
816 : * Thus wakeups don't happen until needed.
817 : */
818 2 : static void __locks_insert_block(struct file_lock *blocker,
819 : struct file_lock *waiter,
820 : bool conflict(struct file_lock *,
821 : struct file_lock *))
822 : {
823 2 : struct file_lock *fl;
824 2 : BUG_ON(!list_empty(&waiter->fl_blocked_member));
825 :
826 2 : new_blocker:
827 2 : list_for_each_entry(fl, &blocker->fl_blocked_requests, fl_blocked_member)
828 0 : if (conflict(fl, waiter)) {
829 0 : blocker = fl;
830 0 : goto new_blocker;
831 : }
832 2 : waiter->fl_blocker = blocker;
833 2 : list_add_tail(&waiter->fl_blocked_member, &blocker->fl_blocked_requests);
834 2 : if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
835 2 : locks_insert_global_blocked(waiter);
836 :
837 : /* The requests in waiter->fl_blocked are known to conflict with
838 : * waiter, but might not conflict with blocker, or the requests
839 : * and lock which block it. So they all need to be woken.
840 : */
841 2 : __locks_wake_up_blocks(waiter);
842 2 : }
843 :
844 : /* Must be called with flc_lock held. */
845 0 : static void locks_insert_block(struct file_lock *blocker,
846 : struct file_lock *waiter,
847 : bool conflict(struct file_lock *,
848 : struct file_lock *))
849 : {
850 0 : spin_lock(&blocked_lock_lock);
851 0 : __locks_insert_block(blocker, waiter, conflict);
852 0 : spin_unlock(&blocked_lock_lock);
853 0 : }
854 :
855 : /*
856 : * Wake up processes blocked waiting for blocker.
857 : *
858 : * Must be called with the inode->flc_lock held!
859 : */
860 150 : static void locks_wake_up_blocks(struct file_lock *blocker)
861 : {
862 : /*
863 : * Avoid taking global lock if list is empty. This is safe since new
864 : * blocked requests are only added to the list under the flc_lock, and
865 : * the flc_lock is always held here. Note that removal from the
866 : * fl_blocked_requests list does not require the flc_lock, so we must
867 : * recheck list_empty() after acquiring the blocked_lock_lock.
868 : */
869 150 : if (list_empty(&blocker->fl_blocked_requests))
870 : return;
871 :
872 2 : spin_lock(&blocked_lock_lock);
873 2 : __locks_wake_up_blocks(blocker);
874 2 : spin_unlock(&blocked_lock_lock);
875 : }
876 :
877 : static void
878 155 : locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
879 : {
880 155 : list_add_tail(&fl->fl_list, before);
881 0 : locks_insert_global_locks(fl);
882 0 : }
883 :
884 : static void
885 150 : locks_unlink_lock_ctx(struct file_lock *fl)
886 : {
887 150 : locks_delete_global_locks(fl);
888 150 : list_del_init(&fl->fl_list);
889 150 : locks_wake_up_blocks(fl);
890 150 : }
891 :
892 : static void
893 150 : locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
894 : {
895 0 : locks_unlink_lock_ctx(fl);
896 0 : if (dispose)
897 150 : list_add(&fl->fl_list, dispose);
898 : else
899 0 : locks_free_lock(fl);
900 0 : }
901 :
902 : /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
903 : * checks for shared/exclusive status of overlapping locks.
904 : */
905 2 : static bool locks_conflict(struct file_lock *caller_fl,
906 : struct file_lock *sys_fl)
907 : {
908 2 : if (sys_fl->fl_type == F_WRLCK)
909 : return true;
910 0 : if (caller_fl->fl_type == F_WRLCK)
911 0 : return true;
912 : return false;
913 : }
914 :
915 : /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
916 : * checking before calling the locks_conflict().
917 : */
918 2 : static bool posix_locks_conflict(struct file_lock *caller_fl,
919 : struct file_lock *sys_fl)
920 : {
921 : /* POSIX locks owned by the same process do not conflict with
922 : * each other.
923 : */
924 2 : if (posix_same_owner(caller_fl, sys_fl))
925 : return false;
926 :
927 : /* Check whether they overlap */
928 2 : if (!locks_overlap(caller_fl, sys_fl))
929 : return false;
930 :
931 2 : return locks_conflict(caller_fl, sys_fl);
932 : }
933 :
934 : /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
935 : * checking before calling the locks_conflict().
936 : */
937 0 : static bool flock_locks_conflict(struct file_lock *caller_fl,
938 : struct file_lock *sys_fl)
939 : {
940 : /* FLOCK locks referring to the same filp do not conflict with
941 : * each other.
942 : */
943 0 : if (caller_fl->fl_file == sys_fl->fl_file)
944 : return false;
945 0 : if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
946 : return false;
947 :
948 0 : return locks_conflict(caller_fl, sys_fl);
949 : }
950 :
951 : void
952 0 : posix_test_lock(struct file *filp, struct file_lock *fl)
953 : {
954 0 : struct file_lock *cfl;
955 0 : struct file_lock_context *ctx;
956 0 : struct inode *inode = locks_inode(filp);
957 :
958 0 : ctx = smp_load_acquire(&inode->i_flctx);
959 0 : if (!ctx || list_empty_careful(&ctx->flc_posix)) {
960 0 : fl->fl_type = F_UNLCK;
961 0 : return;
962 : }
963 :
964 0 : spin_lock(&ctx->flc_lock);
965 0 : list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
966 0 : if (posix_locks_conflict(fl, cfl)) {
967 0 : locks_copy_conflock(fl, cfl);
968 0 : goto out;
969 : }
970 : }
971 0 : fl->fl_type = F_UNLCK;
972 0 : out:
973 0 : spin_unlock(&ctx->flc_lock);
974 : return;
975 : }
976 : EXPORT_SYMBOL(posix_test_lock);
977 :
978 : /*
979 : * Deadlock detection:
980 : *
981 : * We attempt to detect deadlocks that are due purely to posix file
982 : * locks.
983 : *
984 : * We assume that a task can be waiting for at most one lock at a time.
985 : * So for any acquired lock, the process holding that lock may be
986 : * waiting on at most one other lock. That lock in turns may be held by
987 : * someone waiting for at most one other lock. Given a requested lock
988 : * caller_fl which is about to wait for a conflicting lock block_fl, we
989 : * follow this chain of waiters to ensure we are not about to create a
990 : * cycle.
991 : *
992 : * Since we do this before we ever put a process to sleep on a lock, we
993 : * are ensured that there is never a cycle; that is what guarantees that
994 : * the while() loop in posix_locks_deadlock() eventually completes.
995 : *
996 : * Note: the above assumption may not be true when handling lock
997 : * requests from a broken NFS client. It may also fail in the presence
998 : * of tasks (such as posix threads) sharing the same open file table.
999 : * To handle those cases, we just bail out after a few iterations.
1000 : *
1001 : * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
1002 : * Because the owner is not even nominally tied to a thread of
1003 : * execution, the deadlock detection below can't reasonably work well. Just
1004 : * skip it for those.
1005 : *
1006 : * In principle, we could do a more limited deadlock detection on FL_OFDLCK
1007 : * locks that just checks for the case where two tasks are attempting to
1008 : * upgrade from read to write locks on the same inode.
1009 : */
1010 :
1011 : #define MAX_DEADLK_ITERATIONS 10
1012 :
1013 : /* Find a lock that the owner of the given block_fl is blocking on. */
1014 2 : static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
1015 : {
1016 2 : struct file_lock *fl;
1017 :
1018 4 : hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
1019 0 : if (posix_same_owner(fl, block_fl)) {
1020 0 : while (fl->fl_blocker)
1021 : fl = fl->fl_blocker;
1022 0 : return fl;
1023 : }
1024 : }
1025 : return NULL;
1026 : }
1027 :
1028 : /* Must be called with the blocked_lock_lock held! */
1029 2 : static int posix_locks_deadlock(struct file_lock *caller_fl,
1030 : struct file_lock *block_fl)
1031 : {
1032 2 : int i = 0;
1033 :
1034 6 : lockdep_assert_held(&blocked_lock_lock);
1035 :
1036 : /*
1037 : * This deadlock detector can't reasonably detect deadlocks with
1038 : * FL_OFDLCK locks, since they aren't owned by a process, per-se.
1039 : */
1040 2 : if (IS_OFDLCK(caller_fl))
1041 : return 0;
1042 :
1043 2 : while ((block_fl = what_owner_is_waiting_for(block_fl))) {
1044 0 : if (i++ > MAX_DEADLK_ITERATIONS)
1045 : return 0;
1046 0 : if (posix_same_owner(caller_fl, block_fl))
1047 : return 1;
1048 : }
1049 : return 0;
1050 : }
1051 :
1052 : /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
1053 : * after any leases, but before any posix locks.
1054 : *
1055 : * Note that if called with an FL_EXISTS argument, the caller may determine
1056 : * whether or not a lock was successfully freed by testing the return
1057 : * value for -ENOENT.
1058 : */
1059 227 : static int flock_lock_inode(struct inode *inode, struct file_lock *request)
1060 : {
1061 227 : struct file_lock *new_fl = NULL;
1062 227 : struct file_lock *fl;
1063 227 : struct file_lock_context *ctx;
1064 227 : int error = 0;
1065 227 : bool found = false;
1066 227 : LIST_HEAD(dispose);
1067 :
1068 227 : ctx = locks_get_lock_context(inode, request->fl_type);
1069 227 : if (!ctx) {
1070 0 : if (request->fl_type != F_UNLCK)
1071 : return -ENOMEM;
1072 0 : return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
1073 : }
1074 :
1075 227 : if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
1076 96 : new_fl = locks_alloc_lock();
1077 96 : if (!new_fl)
1078 : return -ENOMEM;
1079 : }
1080 :
1081 227 : percpu_down_read(&file_rwsem);
1082 227 : spin_lock(&ctx->flc_lock);
1083 227 : if (request->fl_flags & FL_ACCESS)
1084 0 : goto find_conflict;
1085 :
1086 264 : list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
1087 131 : if (request->fl_file != fl->fl_file)
1088 37 : continue;
1089 94 : if (request->fl_type == fl->fl_type)
1090 0 : goto out;
1091 94 : found = true;
1092 94 : locks_delete_lock_ctx(fl, &dispose);
1093 : break;
1094 : }
1095 :
1096 227 : if (request->fl_type == F_UNLCK) {
1097 131 : if ((request->fl_flags & FL_EXISTS) && !found)
1098 0 : error = -ENOENT;
1099 131 : goto out;
1100 : }
1101 :
1102 96 : find_conflict:
1103 96 : list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
1104 0 : if (!flock_locks_conflict(request, fl))
1105 0 : continue;
1106 0 : error = -EAGAIN;
1107 0 : if (!(request->fl_flags & FL_SLEEP))
1108 0 : goto out;
1109 0 : error = FILE_LOCK_DEFERRED;
1110 0 : locks_insert_block(fl, request, flock_locks_conflict);
1111 0 : goto out;
1112 : }
1113 96 : if (request->fl_flags & FL_ACCESS)
1114 0 : goto out;
1115 96 : locks_copy_lock(new_fl, request);
1116 96 : locks_move_blocks(new_fl, request);
1117 96 : locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
1118 96 : new_fl = NULL;
1119 96 : error = 0;
1120 :
1121 227 : out:
1122 227 : spin_unlock(&ctx->flc_lock);
1123 227 : percpu_up_read(&file_rwsem);
1124 227 : if (new_fl)
1125 0 : locks_free_lock(new_fl);
1126 227 : locks_dispose_list(&dispose);
1127 227 : trace_flock_lock_inode(inode, request, error);
1128 227 : return error;
1129 : }
1130 :
1131 134 : static int posix_lock_inode(struct inode *inode, struct file_lock *request,
1132 : struct file_lock *conflock)
1133 : {
1134 134 : struct file_lock *fl, *tmp;
1135 134 : struct file_lock *new_fl = NULL;
1136 134 : struct file_lock *new_fl2 = NULL;
1137 134 : struct file_lock *left = NULL;
1138 134 : struct file_lock *right = NULL;
1139 134 : struct file_lock_context *ctx;
1140 134 : int error;
1141 134 : bool added = false;
1142 134 : LIST_HEAD(dispose);
1143 :
1144 134 : ctx = locks_get_lock_context(inode, request->fl_type);
1145 134 : if (!ctx)
1146 0 : return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
1147 :
1148 : /*
1149 : * We may need two file_lock structures for this operation,
1150 : * so we get them in advance to avoid races.
1151 : *
1152 : * In some cases we can be sure, that no new locks will be needed
1153 : */
1154 134 : if (!(request->fl_flags & FL_ACCESS) &&
1155 134 : (request->fl_type != F_UNLCK ||
1156 73 : request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1157 61 : new_fl = locks_alloc_lock();
1158 61 : new_fl2 = locks_alloc_lock();
1159 : }
1160 :
1161 134 : percpu_down_read(&file_rwsem);
1162 134 : spin_lock(&ctx->flc_lock);
1163 : /*
1164 : * New lock request. Walk all POSIX locks and look for conflicts. If
1165 : * there are any, either return error or put the request on the
1166 : * blocker's list of waiters and the global blocked_hash.
1167 : */
1168 134 : if (request->fl_type != F_UNLCK) {
1169 61 : list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1170 2 : if (!posix_locks_conflict(request, fl))
1171 0 : continue;
1172 2 : if (conflock)
1173 0 : locks_copy_conflock(conflock, fl);
1174 2 : error = -EAGAIN;
1175 2 : if (!(request->fl_flags & FL_SLEEP))
1176 0 : goto out;
1177 : /*
1178 : * Deadlock detection and insertion into the blocked
1179 : * locks list must be done while holding the same lock!
1180 : */
1181 2 : error = -EDEADLK;
1182 2 : spin_lock(&blocked_lock_lock);
1183 : /*
1184 : * Ensure that we don't find any locks blocked on this
1185 : * request during deadlock detection.
1186 : */
1187 2 : __locks_wake_up_blocks(request);
1188 2 : if (likely(!posix_locks_deadlock(request, fl))) {
1189 2 : error = FILE_LOCK_DEFERRED;
1190 2 : __locks_insert_block(fl, request,
1191 : posix_locks_conflict);
1192 : }
1193 2 : spin_unlock(&blocked_lock_lock);
1194 2 : goto out;
1195 : }
1196 : }
1197 :
1198 : /* If we're just looking for a conflict, we're done. */
1199 132 : error = 0;
1200 132 : if (request->fl_flags & FL_ACCESS)
1201 0 : goto out;
1202 :
1203 : /* Find the first old lock with the same owner as the new lock */
1204 149 : list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1205 73 : if (posix_same_owner(request, fl))
1206 : break;
1207 : }
1208 :
1209 : /* Process locks with this owner. */
1210 188 : list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1211 56 : if (!posix_same_owner(request, fl))
1212 : break;
1213 :
1214 : /* Detect adjacent or overlapping regions (if same lock type) */
1215 56 : if (request->fl_type == fl->fl_type) {
1216 : /* In all comparisons of start vs end, use
1217 : * "start - 1" rather than "end + 1". If end
1218 : * is OFFSET_MAX, end + 1 will become negative.
1219 : */
1220 0 : if (fl->fl_end < request->fl_start - 1)
1221 0 : continue;
1222 : /* If the next lock in the list has entirely bigger
1223 : * addresses than the new one, insert the lock here.
1224 : */
1225 0 : if (fl->fl_start - 1 > request->fl_end)
1226 : break;
1227 :
1228 : /* If we come here, the new and old lock are of the
1229 : * same type and adjacent or overlapping. Make one
1230 : * lock yielding from the lower start address of both
1231 : * locks to the higher end address.
1232 : */
1233 0 : if (fl->fl_start > request->fl_start)
1234 0 : fl->fl_start = request->fl_start;
1235 : else
1236 0 : request->fl_start = fl->fl_start;
1237 0 : if (fl->fl_end < request->fl_end)
1238 0 : fl->fl_end = request->fl_end;
1239 : else
1240 0 : request->fl_end = fl->fl_end;
1241 0 : if (added) {
1242 0 : locks_delete_lock_ctx(fl, &dispose);
1243 0 : continue;
1244 : }
1245 : request = fl;
1246 : added = true;
1247 : } else {
1248 : /* Processing for different lock types is a bit
1249 : * more complex.
1250 : */
1251 56 : if (fl->fl_end < request->fl_start)
1252 0 : continue;
1253 56 : if (fl->fl_start > request->fl_end)
1254 : break;
1255 56 : if (request->fl_type == F_UNLCK)
1256 56 : added = true;
1257 56 : if (fl->fl_start < request->fl_start)
1258 0 : left = fl;
1259 : /* If the next lock in the list has a higher end
1260 : * address than the new one, insert the new one here.
1261 : */
1262 56 : if (fl->fl_end > request->fl_end) {
1263 : right = fl;
1264 : break;
1265 : }
1266 56 : if (fl->fl_start >= request->fl_start) {
1267 : /* The new lock completely replaces an old
1268 : * one (This may happen several times).
1269 : */
1270 56 : if (added) {
1271 56 : locks_delete_lock_ctx(fl, &dispose);
1272 56 : continue;
1273 : }
1274 : /*
1275 : * Replace the old lock with new_fl, and
1276 : * remove the old one. It's safe to do the
1277 : * insert here since we know that we won't be
1278 : * using new_fl later, and that the lock is
1279 : * just replacing an existing lock.
1280 : */
1281 0 : error = -ENOLCK;
1282 0 : if (!new_fl)
1283 0 : goto out;
1284 0 : locks_copy_lock(new_fl, request);
1285 0 : locks_move_blocks(new_fl, request);
1286 0 : request = new_fl;
1287 0 : new_fl = NULL;
1288 0 : locks_insert_lock_ctx(request, &fl->fl_list);
1289 0 : locks_delete_lock_ctx(fl, &dispose);
1290 0 : added = true;
1291 : }
1292 : }
1293 : }
1294 :
1295 : /*
1296 : * The above code only modifies existing locks in case of merging or
1297 : * replacing. If new lock(s) need to be inserted all modifications are
1298 : * done below this, so it's safe yet to bail out.
1299 : */
1300 132 : error = -ENOLCK; /* "no luck" */
1301 132 : if (right && left == right && !new_fl2)
1302 0 : goto out;
1303 :
1304 132 : error = 0;
1305 132 : if (!added) {
1306 76 : if (request->fl_type == F_UNLCK) {
1307 17 : if (request->fl_flags & FL_EXISTS)
1308 0 : error = -ENOENT;
1309 17 : goto out;
1310 : }
1311 :
1312 59 : if (!new_fl) {
1313 0 : error = -ENOLCK;
1314 0 : goto out;
1315 : }
1316 59 : locks_copy_lock(new_fl, request);
1317 59 : locks_move_blocks(new_fl, request);
1318 59 : locks_insert_lock_ctx(new_fl, &fl->fl_list);
1319 59 : fl = new_fl;
1320 59 : new_fl = NULL;
1321 : }
1322 115 : if (right) {
1323 0 : if (left == right) {
1324 : /* The new lock breaks the old one in two pieces,
1325 : * so we have to use the second new lock.
1326 : */
1327 0 : left = new_fl2;
1328 0 : new_fl2 = NULL;
1329 0 : locks_copy_lock(left, right);
1330 0 : locks_insert_lock_ctx(left, &fl->fl_list);
1331 : }
1332 0 : right->fl_start = request->fl_end + 1;
1333 0 : locks_wake_up_blocks(right);
1334 : }
1335 115 : if (left) {
1336 0 : left->fl_end = request->fl_start - 1;
1337 0 : locks_wake_up_blocks(left);
1338 : }
1339 115 : out:
1340 134 : spin_unlock(&ctx->flc_lock);
1341 134 : percpu_up_read(&file_rwsem);
1342 : /*
1343 : * Free any unused locks.
1344 : */
1345 134 : if (new_fl)
1346 2 : locks_free_lock(new_fl);
1347 134 : if (new_fl2)
1348 61 : locks_free_lock(new_fl2);
1349 134 : locks_dispose_list(&dispose);
1350 134 : trace_posix_lock_inode(inode, request, error);
1351 :
1352 134 : return error;
1353 : }
1354 :
1355 : /**
1356 : * posix_lock_file - Apply a POSIX-style lock to a file
1357 : * @filp: The file to apply the lock to
1358 : * @fl: The lock to be applied
1359 : * @conflock: Place to return a copy of the conflicting lock, if found.
1360 : *
1361 : * Add a POSIX style lock to a file.
1362 : * We merge adjacent & overlapping locks whenever possible.
1363 : * POSIX locks are sorted by owner task, then by starting address
1364 : *
1365 : * Note that if called with an FL_EXISTS argument, the caller may determine
1366 : * whether or not a lock was successfully freed by testing the return
1367 : * value for -ENOENT.
1368 : */
1369 134 : int posix_lock_file(struct file *filp, struct file_lock *fl,
1370 : struct file_lock *conflock)
1371 : {
1372 0 : return posix_lock_inode(locks_inode(filp), fl, conflock);
1373 : }
1374 : EXPORT_SYMBOL(posix_lock_file);
1375 :
1376 : /**
1377 : * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1378 : * @inode: inode of file to which lock request should be applied
1379 : * @fl: The lock to be applied
1380 : *
1381 : * Apply a POSIX style lock request to an inode.
1382 : */
1383 0 : static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1384 : {
1385 0 : int error;
1386 0 : might_sleep ();
1387 0 : for (;;) {
1388 0 : error = posix_lock_inode(inode, fl, NULL);
1389 0 : if (error != FILE_LOCK_DEFERRED)
1390 : break;
1391 0 : error = wait_event_interruptible(fl->fl_wait,
1392 : list_empty(&fl->fl_blocked_member));
1393 0 : if (error)
1394 : break;
1395 : }
1396 0 : locks_delete_block(fl);
1397 0 : return error;
1398 : }
1399 :
1400 : #ifdef CONFIG_MANDATORY_FILE_LOCKING
1401 : /**
1402 : * locks_mandatory_locked - Check for an active lock
1403 : * @file: the file to check
1404 : *
1405 : * Searches the inode's list of locks to find any POSIX locks which conflict.
1406 : * This function is called from locks_verify_locked() only.
1407 : */
1408 : int locks_mandatory_locked(struct file *file)
1409 : {
1410 : int ret;
1411 : struct inode *inode = locks_inode(file);
1412 : struct file_lock_context *ctx;
1413 : struct file_lock *fl;
1414 :
1415 : ctx = smp_load_acquire(&inode->i_flctx);
1416 : if (!ctx || list_empty_careful(&ctx->flc_posix))
1417 : return 0;
1418 :
1419 : /*
1420 : * Search the lock list for this inode for any POSIX locks.
1421 : */
1422 : spin_lock(&ctx->flc_lock);
1423 : ret = 0;
1424 : list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1425 : if (fl->fl_owner != current->files &&
1426 : fl->fl_owner != file) {
1427 : ret = -EAGAIN;
1428 : break;
1429 : }
1430 : }
1431 : spin_unlock(&ctx->flc_lock);
1432 : return ret;
1433 : }
1434 :
1435 : /**
1436 : * locks_mandatory_area - Check for a conflicting lock
1437 : * @inode: the file to check
1438 : * @filp: how the file was opened (if it was)
1439 : * @start: first byte in the file to check
1440 : * @end: lastbyte in the file to check
1441 : * @type: %F_WRLCK for a write lock, else %F_RDLCK
1442 : *
1443 : * Searches the inode's list of locks to find any POSIX locks which conflict.
1444 : */
1445 : int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1446 : loff_t end, unsigned char type)
1447 : {
1448 : struct file_lock fl;
1449 : int error;
1450 : bool sleep = false;
1451 :
1452 : locks_init_lock(&fl);
1453 : fl.fl_pid = current->tgid;
1454 : fl.fl_file = filp;
1455 : fl.fl_flags = FL_POSIX | FL_ACCESS;
1456 : if (filp && !(filp->f_flags & O_NONBLOCK))
1457 : sleep = true;
1458 : fl.fl_type = type;
1459 : fl.fl_start = start;
1460 : fl.fl_end = end;
1461 :
1462 : for (;;) {
1463 : if (filp) {
1464 : fl.fl_owner = filp;
1465 : fl.fl_flags &= ~FL_SLEEP;
1466 : error = posix_lock_inode(inode, &fl, NULL);
1467 : if (!error)
1468 : break;
1469 : }
1470 :
1471 : if (sleep)
1472 : fl.fl_flags |= FL_SLEEP;
1473 : fl.fl_owner = current->files;
1474 : error = posix_lock_inode(inode, &fl, NULL);
1475 : if (error != FILE_LOCK_DEFERRED)
1476 : break;
1477 : error = wait_event_interruptible(fl.fl_wait,
1478 : list_empty(&fl.fl_blocked_member));
1479 : if (!error) {
1480 : /*
1481 : * If we've been sleeping someone might have
1482 : * changed the permissions behind our back.
1483 : */
1484 : if (__mandatory_lock(inode))
1485 : continue;
1486 : }
1487 :
1488 : break;
1489 : }
1490 : locks_delete_block(&fl);
1491 :
1492 : return error;
1493 : }
1494 : EXPORT_SYMBOL(locks_mandatory_area);
1495 : #endif /* CONFIG_MANDATORY_FILE_LOCKING */
1496 :
1497 0 : static void lease_clear_pending(struct file_lock *fl, int arg)
1498 : {
1499 0 : switch (arg) {
1500 0 : case F_UNLCK:
1501 0 : fl->fl_flags &= ~FL_UNLOCK_PENDING;
1502 0 : fallthrough;
1503 0 : case F_RDLCK:
1504 0 : fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1505 : }
1506 0 : }
1507 :
1508 : /* We already had a lease on this file; just change its type */
1509 0 : int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
1510 : {
1511 0 : int error = assign_type(fl, arg);
1512 :
1513 0 : if (error)
1514 : return error;
1515 0 : lease_clear_pending(fl, arg);
1516 0 : locks_wake_up_blocks(fl);
1517 0 : if (arg == F_UNLCK) {
1518 0 : struct file *filp = fl->fl_file;
1519 :
1520 0 : f_delown(filp);
1521 0 : filp->f_owner.signum = 0;
1522 0 : fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1523 0 : if (fl->fl_fasync != NULL) {
1524 0 : printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1525 0 : fl->fl_fasync = NULL;
1526 : }
1527 0 : locks_delete_lock_ctx(fl, dispose);
1528 : }
1529 : return 0;
1530 : }
1531 : EXPORT_SYMBOL(lease_modify);
1532 :
1533 0 : static bool past_time(unsigned long then)
1534 : {
1535 0 : if (!then)
1536 : /* 0 is a special value meaning "this never expires": */
1537 : return false;
1538 0 : return time_after(jiffies, then);
1539 : }
1540 :
1541 0 : static void time_out_leases(struct inode *inode, struct list_head *dispose)
1542 : {
1543 0 : struct file_lock_context *ctx = inode->i_flctx;
1544 0 : struct file_lock *fl, *tmp;
1545 :
1546 0 : lockdep_assert_held(&ctx->flc_lock);
1547 :
1548 0 : list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1549 0 : trace_time_out_leases(inode, fl);
1550 0 : if (past_time(fl->fl_downgrade_time))
1551 0 : lease_modify(fl, F_RDLCK, dispose);
1552 0 : if (past_time(fl->fl_break_time))
1553 0 : lease_modify(fl, F_UNLCK, dispose);
1554 : }
1555 0 : }
1556 :
1557 0 : static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1558 : {
1559 0 : bool rc;
1560 :
1561 0 : if (lease->fl_lmops->lm_breaker_owns_lease
1562 0 : && lease->fl_lmops->lm_breaker_owns_lease(lease))
1563 : return false;
1564 0 : if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) {
1565 0 : rc = false;
1566 0 : goto trace;
1567 : }
1568 0 : if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) {
1569 0 : rc = false;
1570 0 : goto trace;
1571 : }
1572 :
1573 0 : rc = locks_conflict(breaker, lease);
1574 0 : trace:
1575 0 : trace_leases_conflict(rc, lease, breaker);
1576 0 : return rc;
1577 : }
1578 :
1579 : static bool
1580 0 : any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1581 : {
1582 0 : struct file_lock_context *ctx = inode->i_flctx;
1583 0 : struct file_lock *fl;
1584 :
1585 0 : lockdep_assert_held(&ctx->flc_lock);
1586 :
1587 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1588 0 : if (leases_conflict(fl, breaker))
1589 : return true;
1590 : }
1591 : return false;
1592 : }
1593 :
1594 : /**
1595 : * __break_lease - revoke all outstanding leases on file
1596 : * @inode: the inode of the file to return
1597 : * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1598 : * break all leases
1599 : * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1600 : * only delegations
1601 : *
1602 : * break_lease (inlined for speed) has checked there already is at least
1603 : * some kind of lock (maybe a lease) on this file. Leases are broken on
1604 : * a call to open() or truncate(). This function can sleep unless you
1605 : * specified %O_NONBLOCK to your open().
1606 : */
1607 0 : int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1608 : {
1609 0 : int error = 0;
1610 0 : struct file_lock_context *ctx;
1611 0 : struct file_lock *new_fl, *fl, *tmp;
1612 0 : unsigned long break_time;
1613 0 : int want_write = (mode & O_ACCMODE) != O_RDONLY;
1614 0 : LIST_HEAD(dispose);
1615 :
1616 0 : new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1617 0 : if (IS_ERR(new_fl))
1618 0 : return PTR_ERR(new_fl);
1619 0 : new_fl->fl_flags = type;
1620 :
1621 : /* typically we will check that ctx is non-NULL before calling */
1622 0 : ctx = smp_load_acquire(&inode->i_flctx);
1623 0 : if (!ctx) {
1624 0 : WARN_ON_ONCE(1);
1625 0 : goto free_lock;
1626 : }
1627 :
1628 0 : percpu_down_read(&file_rwsem);
1629 0 : spin_lock(&ctx->flc_lock);
1630 :
1631 0 : time_out_leases(inode, &dispose);
1632 :
1633 0 : if (!any_leases_conflict(inode, new_fl))
1634 0 : goto out;
1635 :
1636 0 : break_time = 0;
1637 0 : if (lease_break_time > 0) {
1638 0 : break_time = jiffies + lease_break_time * HZ;
1639 0 : if (break_time == 0)
1640 : break_time++; /* so that 0 means no break time */
1641 : }
1642 :
1643 0 : list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1644 0 : if (!leases_conflict(fl, new_fl))
1645 0 : continue;
1646 0 : if (want_write) {
1647 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
1648 0 : continue;
1649 0 : fl->fl_flags |= FL_UNLOCK_PENDING;
1650 0 : fl->fl_break_time = break_time;
1651 : } else {
1652 0 : if (lease_breaking(fl))
1653 0 : continue;
1654 0 : fl->fl_flags |= FL_DOWNGRADE_PENDING;
1655 0 : fl->fl_downgrade_time = break_time;
1656 : }
1657 0 : if (fl->fl_lmops->lm_break(fl))
1658 0 : locks_delete_lock_ctx(fl, &dispose);
1659 : }
1660 :
1661 0 : if (list_empty(&ctx->flc_lease))
1662 0 : goto out;
1663 :
1664 0 : if (mode & O_NONBLOCK) {
1665 0 : trace_break_lease_noblock(inode, new_fl);
1666 0 : error = -EWOULDBLOCK;
1667 0 : goto out;
1668 : }
1669 :
1670 0 : restart:
1671 0 : fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1672 0 : break_time = fl->fl_break_time;
1673 0 : if (break_time != 0)
1674 0 : break_time -= jiffies;
1675 0 : if (break_time == 0)
1676 : break_time++;
1677 0 : locks_insert_block(fl, new_fl, leases_conflict);
1678 0 : trace_break_lease_block(inode, new_fl);
1679 0 : spin_unlock(&ctx->flc_lock);
1680 0 : percpu_up_read(&file_rwsem);
1681 :
1682 0 : locks_dispose_list(&dispose);
1683 0 : error = wait_event_interruptible_timeout(new_fl->fl_wait,
1684 : list_empty(&new_fl->fl_blocked_member),
1685 : break_time);
1686 :
1687 0 : percpu_down_read(&file_rwsem);
1688 0 : spin_lock(&ctx->flc_lock);
1689 0 : trace_break_lease_unblock(inode, new_fl);
1690 0 : locks_delete_block(new_fl);
1691 0 : if (error >= 0) {
1692 : /*
1693 : * Wait for the next conflicting lease that has not been
1694 : * broken yet
1695 : */
1696 0 : if (error == 0)
1697 0 : time_out_leases(inode, &dispose);
1698 0 : if (any_leases_conflict(inode, new_fl))
1699 0 : goto restart;
1700 : error = 0;
1701 : }
1702 0 : out:
1703 0 : spin_unlock(&ctx->flc_lock);
1704 0 : percpu_up_read(&file_rwsem);
1705 0 : locks_dispose_list(&dispose);
1706 0 : free_lock:
1707 0 : locks_free_lock(new_fl);
1708 0 : return error;
1709 : }
1710 : EXPORT_SYMBOL(__break_lease);
1711 :
1712 : /**
1713 : * lease_get_mtime - update modified time of an inode with exclusive lease
1714 : * @inode: the inode
1715 : * @time: pointer to a timespec which contains the last modified time
1716 : *
1717 : * This is to force NFS clients to flush their caches for files with
1718 : * exclusive leases. The justification is that if someone has an
1719 : * exclusive lease, then they could be modifying it.
1720 : */
1721 0 : void lease_get_mtime(struct inode *inode, struct timespec64 *time)
1722 : {
1723 0 : bool has_lease = false;
1724 0 : struct file_lock_context *ctx;
1725 0 : struct file_lock *fl;
1726 :
1727 0 : ctx = smp_load_acquire(&inode->i_flctx);
1728 0 : if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1729 0 : spin_lock(&ctx->flc_lock);
1730 0 : fl = list_first_entry_or_null(&ctx->flc_lease,
1731 : struct file_lock, fl_list);
1732 0 : if (fl && (fl->fl_type == F_WRLCK))
1733 0 : has_lease = true;
1734 0 : spin_unlock(&ctx->flc_lock);
1735 : }
1736 :
1737 0 : if (has_lease)
1738 0 : *time = current_time(inode);
1739 0 : }
1740 : EXPORT_SYMBOL(lease_get_mtime);
1741 :
1742 : /**
1743 : * fcntl_getlease - Enquire what lease is currently active
1744 : * @filp: the file
1745 : *
1746 : * The value returned by this function will be one of
1747 : * (if no lease break is pending):
1748 : *
1749 : * %F_RDLCK to indicate a shared lease is held.
1750 : *
1751 : * %F_WRLCK to indicate an exclusive lease is held.
1752 : *
1753 : * %F_UNLCK to indicate no lease is held.
1754 : *
1755 : * (if a lease break is pending):
1756 : *
1757 : * %F_RDLCK to indicate an exclusive lease needs to be
1758 : * changed to a shared lease (or removed).
1759 : *
1760 : * %F_UNLCK to indicate the lease needs to be removed.
1761 : *
1762 : * XXX: sfr & willy disagree over whether F_INPROGRESS
1763 : * should be returned to userspace.
1764 : */
1765 0 : int fcntl_getlease(struct file *filp)
1766 : {
1767 0 : struct file_lock *fl;
1768 0 : struct inode *inode = locks_inode(filp);
1769 0 : struct file_lock_context *ctx;
1770 0 : int type = F_UNLCK;
1771 0 : LIST_HEAD(dispose);
1772 :
1773 0 : ctx = smp_load_acquire(&inode->i_flctx);
1774 0 : if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1775 0 : percpu_down_read(&file_rwsem);
1776 0 : spin_lock(&ctx->flc_lock);
1777 0 : time_out_leases(inode, &dispose);
1778 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1779 0 : if (fl->fl_file != filp)
1780 0 : continue;
1781 0 : type = target_leasetype(fl);
1782 : break;
1783 : }
1784 0 : spin_unlock(&ctx->flc_lock);
1785 0 : percpu_up_read(&file_rwsem);
1786 :
1787 0 : locks_dispose_list(&dispose);
1788 : }
1789 0 : return type;
1790 : }
1791 :
1792 : /**
1793 : * check_conflicting_open - see if the given file points to an inode that has
1794 : * an existing open that would conflict with the
1795 : * desired lease.
1796 : * @filp: file to check
1797 : * @arg: type of lease that we're trying to acquire
1798 : * @flags: current lock flags
1799 : *
1800 : * Check to see if there's an existing open fd on this file that would
1801 : * conflict with the lease we're trying to set.
1802 : */
1803 : static int
1804 0 : check_conflicting_open(struct file *filp, const long arg, int flags)
1805 : {
1806 0 : struct inode *inode = locks_inode(filp);
1807 0 : int self_wcount = 0, self_rcount = 0;
1808 :
1809 0 : if (flags & FL_LAYOUT)
1810 : return 0;
1811 0 : if (flags & FL_DELEG)
1812 : /* We leave these checks to the caller. */
1813 : return 0;
1814 :
1815 0 : if (arg == F_RDLCK)
1816 0 : return inode_is_open_for_write(inode) ? -EAGAIN : 0;
1817 0 : else if (arg != F_WRLCK)
1818 : return 0;
1819 :
1820 : /*
1821 : * Make sure that only read/write count is from lease requestor.
1822 : * Note that this will result in denying write leases when i_writecount
1823 : * is negative, which is what we want. (We shouldn't grant write leases
1824 : * on files open for execution.)
1825 : */
1826 0 : if (filp->f_mode & FMODE_WRITE)
1827 : self_wcount = 1;
1828 0 : else if (filp->f_mode & FMODE_READ)
1829 : self_rcount = 1;
1830 :
1831 0 : if (atomic_read(&inode->i_writecount) != self_wcount ||
1832 0 : atomic_read(&inode->i_readcount) != self_rcount)
1833 0 : return -EAGAIN;
1834 :
1835 : return 0;
1836 : }
1837 :
1838 : static int
1839 0 : generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1840 : {
1841 0 : struct file_lock *fl, *my_fl = NULL, *lease;
1842 0 : struct inode *inode = locks_inode(filp);
1843 0 : struct file_lock_context *ctx;
1844 0 : bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1845 0 : int error;
1846 0 : LIST_HEAD(dispose);
1847 :
1848 0 : lease = *flp;
1849 0 : trace_generic_add_lease(inode, lease);
1850 :
1851 : /* Note that arg is never F_UNLCK here */
1852 0 : ctx = locks_get_lock_context(inode, arg);
1853 0 : if (!ctx)
1854 : return -ENOMEM;
1855 :
1856 : /*
1857 : * In the delegation case we need mutual exclusion with
1858 : * a number of operations that take the i_mutex. We trylock
1859 : * because delegations are an optional optimization, and if
1860 : * there's some chance of a conflict--we'd rather not
1861 : * bother, maybe that's a sign this just isn't a good file to
1862 : * hand out a delegation on.
1863 : */
1864 0 : if (is_deleg && !inode_trylock(inode))
1865 : return -EAGAIN;
1866 :
1867 0 : if (is_deleg && arg == F_WRLCK) {
1868 : /* Write delegations are not currently supported: */
1869 0 : inode_unlock(inode);
1870 0 : WARN_ON_ONCE(1);
1871 0 : return -EINVAL;
1872 : }
1873 :
1874 0 : percpu_down_read(&file_rwsem);
1875 0 : spin_lock(&ctx->flc_lock);
1876 0 : time_out_leases(inode, &dispose);
1877 0 : error = check_conflicting_open(filp, arg, lease->fl_flags);
1878 0 : if (error)
1879 0 : goto out;
1880 :
1881 : /*
1882 : * At this point, we know that if there is an exclusive
1883 : * lease on this file, then we hold it on this filp
1884 : * (otherwise our open of this file would have blocked).
1885 : * And if we are trying to acquire an exclusive lease,
1886 : * then the file is not open by anyone (including us)
1887 : * except for this filp.
1888 : */
1889 0 : error = -EAGAIN;
1890 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1891 0 : if (fl->fl_file == filp &&
1892 0 : fl->fl_owner == lease->fl_owner) {
1893 0 : my_fl = fl;
1894 0 : continue;
1895 : }
1896 :
1897 : /*
1898 : * No exclusive leases if someone else has a lease on
1899 : * this file:
1900 : */
1901 0 : if (arg == F_WRLCK)
1902 0 : goto out;
1903 : /*
1904 : * Modifying our existing lease is OK, but no getting a
1905 : * new lease if someone else is opening for write:
1906 : */
1907 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
1908 0 : goto out;
1909 : }
1910 :
1911 0 : if (my_fl != NULL) {
1912 0 : lease = my_fl;
1913 0 : error = lease->fl_lmops->lm_change(lease, arg, &dispose);
1914 0 : if (error)
1915 0 : goto out;
1916 0 : goto out_setup;
1917 : }
1918 :
1919 0 : error = -EINVAL;
1920 0 : if (!leases_enable)
1921 0 : goto out;
1922 :
1923 0 : locks_insert_lock_ctx(lease, &ctx->flc_lease);
1924 : /*
1925 : * The check in break_lease() is lockless. It's possible for another
1926 : * open to race in after we did the earlier check for a conflicting
1927 : * open but before the lease was inserted. Check again for a
1928 : * conflicting open and cancel the lease if there is one.
1929 : *
1930 : * We also add a barrier here to ensure that the insertion of the lock
1931 : * precedes these checks.
1932 : */
1933 0 : smp_mb();
1934 0 : error = check_conflicting_open(filp, arg, lease->fl_flags);
1935 0 : if (error) {
1936 0 : locks_unlink_lock_ctx(lease);
1937 0 : goto out;
1938 : }
1939 :
1940 0 : out_setup:
1941 0 : if (lease->fl_lmops->lm_setup)
1942 0 : lease->fl_lmops->lm_setup(lease, priv);
1943 0 : out:
1944 0 : spin_unlock(&ctx->flc_lock);
1945 0 : percpu_up_read(&file_rwsem);
1946 0 : locks_dispose_list(&dispose);
1947 0 : if (is_deleg)
1948 0 : inode_unlock(inode);
1949 0 : if (!error && !my_fl)
1950 0 : *flp = NULL;
1951 : return error;
1952 : }
1953 :
1954 0 : static int generic_delete_lease(struct file *filp, void *owner)
1955 : {
1956 0 : int error = -EAGAIN;
1957 0 : struct file_lock *fl, *victim = NULL;
1958 0 : struct inode *inode = locks_inode(filp);
1959 0 : struct file_lock_context *ctx;
1960 0 : LIST_HEAD(dispose);
1961 :
1962 0 : ctx = smp_load_acquire(&inode->i_flctx);
1963 0 : if (!ctx) {
1964 0 : trace_generic_delete_lease(inode, NULL);
1965 0 : return error;
1966 : }
1967 :
1968 0 : percpu_down_read(&file_rwsem);
1969 0 : spin_lock(&ctx->flc_lock);
1970 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1971 0 : if (fl->fl_file == filp &&
1972 0 : fl->fl_owner == owner) {
1973 : victim = fl;
1974 : break;
1975 : }
1976 : }
1977 0 : trace_generic_delete_lease(inode, victim);
1978 0 : if (victim)
1979 0 : error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
1980 0 : spin_unlock(&ctx->flc_lock);
1981 0 : percpu_up_read(&file_rwsem);
1982 0 : locks_dispose_list(&dispose);
1983 0 : return error;
1984 : }
1985 :
1986 : /**
1987 : * generic_setlease - sets a lease on an open file
1988 : * @filp: file pointer
1989 : * @arg: type of lease to obtain
1990 : * @flp: input - file_lock to use, output - file_lock inserted
1991 : * @priv: private data for lm_setup (may be NULL if lm_setup
1992 : * doesn't require it)
1993 : *
1994 : * The (input) flp->fl_lmops->lm_break function is required
1995 : * by break_lease().
1996 : */
1997 0 : int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1998 : void **priv)
1999 : {
2000 0 : struct inode *inode = locks_inode(filp);
2001 0 : int error;
2002 :
2003 0 : if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
2004 : return -EACCES;
2005 0 : if (!S_ISREG(inode->i_mode))
2006 : return -EINVAL;
2007 0 : error = security_file_lock(filp, arg);
2008 0 : if (error)
2009 : return error;
2010 :
2011 0 : switch (arg) {
2012 0 : case F_UNLCK:
2013 0 : return generic_delete_lease(filp, *priv);
2014 0 : case F_RDLCK:
2015 : case F_WRLCK:
2016 0 : if (!(*flp)->fl_lmops->lm_break) {
2017 0 : WARN_ON_ONCE(1);
2018 0 : return -ENOLCK;
2019 : }
2020 :
2021 0 : return generic_add_lease(filp, arg, flp, priv);
2022 : default:
2023 : return -EINVAL;
2024 : }
2025 : }
2026 : EXPORT_SYMBOL(generic_setlease);
2027 :
2028 : #if IS_ENABLED(CONFIG_SRCU)
2029 : /*
2030 : * Kernel subsystems can register to be notified on any attempt to set
2031 : * a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd
2032 : * to close files that it may have cached when there is an attempt to set a
2033 : * conflicting lease.
2034 : */
2035 : static struct srcu_notifier_head lease_notifier_chain;
2036 :
2037 : static inline void
2038 1 : lease_notifier_chain_init(void)
2039 : {
2040 1 : srcu_init_notifier_head(&lease_notifier_chain);
2041 : }
2042 :
2043 : static inline void
2044 0 : setlease_notifier(long arg, struct file_lock *lease)
2045 : {
2046 0 : if (arg != F_UNLCK)
2047 0 : srcu_notifier_call_chain(&lease_notifier_chain, arg, lease);
2048 : }
2049 :
2050 0 : int lease_register_notifier(struct notifier_block *nb)
2051 : {
2052 0 : return srcu_notifier_chain_register(&lease_notifier_chain, nb);
2053 : }
2054 : EXPORT_SYMBOL_GPL(lease_register_notifier);
2055 :
2056 0 : void lease_unregister_notifier(struct notifier_block *nb)
2057 : {
2058 0 : srcu_notifier_chain_unregister(&lease_notifier_chain, nb);
2059 0 : }
2060 : EXPORT_SYMBOL_GPL(lease_unregister_notifier);
2061 :
2062 : #else /* !IS_ENABLED(CONFIG_SRCU) */
2063 : static inline void
2064 : lease_notifier_chain_init(void)
2065 : {
2066 : }
2067 :
2068 : static inline void
2069 : setlease_notifier(long arg, struct file_lock *lease)
2070 : {
2071 : }
2072 :
2073 : int lease_register_notifier(struct notifier_block *nb)
2074 : {
2075 : return 0;
2076 : }
2077 : EXPORT_SYMBOL_GPL(lease_register_notifier);
2078 :
2079 : void lease_unregister_notifier(struct notifier_block *nb)
2080 : {
2081 : }
2082 : EXPORT_SYMBOL_GPL(lease_unregister_notifier);
2083 :
2084 : #endif /* IS_ENABLED(CONFIG_SRCU) */
2085 :
2086 : /**
2087 : * vfs_setlease - sets a lease on an open file
2088 : * @filp: file pointer
2089 : * @arg: type of lease to obtain
2090 : * @lease: file_lock to use when adding a lease
2091 : * @priv: private info for lm_setup when adding a lease (may be
2092 : * NULL if lm_setup doesn't require it)
2093 : *
2094 : * Call this to establish a lease on the file. The "lease" argument is not
2095 : * used for F_UNLCK requests and may be NULL. For commands that set or alter
2096 : * an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be
2097 : * set; if not, this function will return -ENOLCK (and generate a scary-looking
2098 : * stack trace).
2099 : *
2100 : * The "priv" pointer is passed directly to the lm_setup function as-is. It
2101 : * may be NULL if the lm_setup operation doesn't require it.
2102 : */
2103 : int
2104 0 : vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
2105 : {
2106 0 : if (lease)
2107 0 : setlease_notifier(arg, *lease);
2108 0 : if (filp->f_op->setlease)
2109 0 : return filp->f_op->setlease(filp, arg, lease, priv);
2110 : else
2111 0 : return generic_setlease(filp, arg, lease, priv);
2112 : }
2113 : EXPORT_SYMBOL_GPL(vfs_setlease);
2114 :
2115 0 : static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
2116 : {
2117 0 : struct file_lock *fl;
2118 0 : struct fasync_struct *new;
2119 0 : int error;
2120 :
2121 0 : fl = lease_alloc(filp, arg);
2122 0 : if (IS_ERR(fl))
2123 0 : return PTR_ERR(fl);
2124 :
2125 0 : new = fasync_alloc();
2126 0 : if (!new) {
2127 0 : locks_free_lock(fl);
2128 0 : return -ENOMEM;
2129 : }
2130 0 : new->fa_fd = fd;
2131 :
2132 0 : error = vfs_setlease(filp, arg, &fl, (void **)&new);
2133 0 : if (fl)
2134 0 : locks_free_lock(fl);
2135 0 : if (new)
2136 0 : fasync_free(new);
2137 : return error;
2138 : }
2139 :
2140 : /**
2141 : * fcntl_setlease - sets a lease on an open file
2142 : * @fd: open file descriptor
2143 : * @filp: file pointer
2144 : * @arg: type of lease to obtain
2145 : *
2146 : * Call this fcntl to establish a lease on the file.
2147 : * Note that you also need to call %F_SETSIG to
2148 : * receive a signal when the lease is broken.
2149 : */
2150 0 : int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
2151 : {
2152 0 : if (arg == F_UNLCK)
2153 0 : return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
2154 0 : return do_fcntl_add_lease(fd, filp, arg);
2155 : }
2156 :
2157 : /**
2158 : * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
2159 : * @inode: inode of the file to apply to
2160 : * @fl: The lock to be applied
2161 : *
2162 : * Apply a FLOCK style lock request to an inode.
2163 : */
2164 150 : static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
2165 : {
2166 150 : int error;
2167 150 : might_sleep();
2168 150 : for (;;) {
2169 300 : error = flock_lock_inode(inode, fl);
2170 150 : if (error != FILE_LOCK_DEFERRED)
2171 : break;
2172 150 : error = wait_event_interruptible(fl->fl_wait,
2173 : list_empty(&fl->fl_blocked_member));
2174 0 : if (error)
2175 : break;
2176 : }
2177 150 : locks_delete_block(fl);
2178 150 : return error;
2179 : }
2180 :
2181 : /**
2182 : * locks_lock_inode_wait - Apply a lock to an inode
2183 : * @inode: inode of the file to apply to
2184 : * @fl: The lock to be applied
2185 : *
2186 : * Apply a POSIX or FLOCK style lock request to an inode.
2187 : */
2188 150 : int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
2189 : {
2190 150 : int res = 0;
2191 150 : switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
2192 0 : case FL_POSIX:
2193 0 : res = posix_lock_inode_wait(inode, fl);
2194 0 : break;
2195 150 : case FL_FLOCK:
2196 150 : res = flock_lock_inode_wait(inode, fl);
2197 150 : break;
2198 0 : default:
2199 0 : BUG();
2200 : }
2201 150 : return res;
2202 : }
2203 : EXPORT_SYMBOL(locks_lock_inode_wait);
2204 :
2205 : /**
2206 : * sys_flock: - flock() system call.
2207 : * @fd: the file descriptor to lock.
2208 : * @cmd: the type of lock to apply.
2209 : *
2210 : * Apply a %FL_FLOCK style lock to an open file descriptor.
2211 : * The @cmd can be one of:
2212 : *
2213 : * - %LOCK_SH -- a shared lock.
2214 : * - %LOCK_EX -- an exclusive lock.
2215 : * - %LOCK_UN -- remove an existing lock.
2216 : * - %LOCK_MAND -- a 'mandatory' flock.
2217 : * This exists to emulate Windows Share Modes.
2218 : *
2219 : * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
2220 : * processes read and write access respectively.
2221 : */
2222 300 : SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
2223 : {
2224 150 : struct fd f = fdget(fd);
2225 150 : struct file_lock *lock;
2226 150 : int can_sleep, unlock;
2227 150 : int error;
2228 :
2229 150 : error = -EBADF;
2230 150 : if (!f.file)
2231 0 : goto out;
2232 :
2233 150 : can_sleep = !(cmd & LOCK_NB);
2234 150 : cmd &= ~LOCK_NB;
2235 150 : unlock = (cmd == LOCK_UN);
2236 :
2237 150 : if (!unlock && !(cmd & LOCK_MAND) &&
2238 96 : !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
2239 0 : goto out_putf;
2240 :
2241 150 : lock = flock_make_lock(f.file, cmd, NULL);
2242 150 : if (IS_ERR(lock)) {
2243 0 : error = PTR_ERR(lock);
2244 0 : goto out_putf;
2245 : }
2246 :
2247 150 : if (can_sleep)
2248 57 : lock->fl_flags |= FL_SLEEP;
2249 :
2250 150 : error = security_file_lock(f.file, lock->fl_type);
2251 150 : if (error)
2252 0 : goto out_free;
2253 :
2254 150 : if (f.file->f_op->flock)
2255 0 : error = f.file->f_op->flock(f.file,
2256 : (can_sleep) ? F_SETLKW : F_SETLK,
2257 : lock);
2258 : else
2259 150 : error = locks_lock_file_wait(f.file, lock);
2260 :
2261 150 : out_free:
2262 150 : locks_free_lock(lock);
2263 :
2264 150 : out_putf:
2265 150 : fdput(f);
2266 150 : out:
2267 150 : return error;
2268 : }
2269 :
2270 : /**
2271 : * vfs_test_lock - test file byte range lock
2272 : * @filp: The file to test lock for
2273 : * @fl: The lock to test; also used to hold result
2274 : *
2275 : * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2276 : * setting conf->fl_type to something other than F_UNLCK.
2277 : */
2278 0 : int vfs_test_lock(struct file *filp, struct file_lock *fl)
2279 : {
2280 0 : if (filp->f_op->lock)
2281 0 : return filp->f_op->lock(filp, F_GETLK, fl);
2282 0 : posix_test_lock(filp, fl);
2283 0 : return 0;
2284 : }
2285 : EXPORT_SYMBOL_GPL(vfs_test_lock);
2286 :
2287 : /**
2288 : * locks_translate_pid - translate a file_lock's fl_pid number into a namespace
2289 : * @fl: The file_lock who's fl_pid should be translated
2290 : * @ns: The namespace into which the pid should be translated
2291 : *
2292 : * Used to tranlate a fl_pid into a namespace virtual pid number
2293 : */
2294 0 : static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns)
2295 : {
2296 0 : pid_t vnr;
2297 0 : struct pid *pid;
2298 :
2299 0 : if (IS_OFDLCK(fl))
2300 : return -1;
2301 0 : if (IS_REMOTELCK(fl))
2302 : return fl->fl_pid;
2303 : /*
2304 : * If the flock owner process is dead and its pid has been already
2305 : * freed, the translation below won't work, but we still want to show
2306 : * flock owner pid number in init pidns.
2307 : */
2308 0 : if (ns == &init_pid_ns)
2309 0 : return (pid_t)fl->fl_pid;
2310 :
2311 0 : rcu_read_lock();
2312 0 : pid = find_pid_ns(fl->fl_pid, &init_pid_ns);
2313 0 : vnr = pid_nr_ns(pid, ns);
2314 0 : rcu_read_unlock();
2315 0 : return vnr;
2316 : }
2317 :
2318 0 : static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2319 : {
2320 0 : flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
2321 : #if BITS_PER_LONG == 32
2322 : /*
2323 : * Make sure we can represent the posix lock via
2324 : * legacy 32bit flock.
2325 : */
2326 : if (fl->fl_start > OFFT_OFFSET_MAX)
2327 : return -EOVERFLOW;
2328 : if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2329 : return -EOVERFLOW;
2330 : #endif
2331 0 : flock->l_start = fl->fl_start;
2332 0 : flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2333 0 : fl->fl_end - fl->fl_start + 1;
2334 0 : flock->l_whence = 0;
2335 0 : flock->l_type = fl->fl_type;
2336 0 : return 0;
2337 : }
2338 :
2339 : #if BITS_PER_LONG == 32
2340 : static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2341 : {
2342 : flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
2343 : flock->l_start = fl->fl_start;
2344 : flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2345 : fl->fl_end - fl->fl_start + 1;
2346 : flock->l_whence = 0;
2347 : flock->l_type = fl->fl_type;
2348 : }
2349 : #endif
2350 :
2351 : /* Report the first existing lock that would conflict with l.
2352 : * This implements the F_GETLK command of fcntl().
2353 : */
2354 0 : int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
2355 : {
2356 0 : struct file_lock *fl;
2357 0 : int error;
2358 :
2359 0 : fl = locks_alloc_lock();
2360 0 : if (fl == NULL)
2361 : return -ENOMEM;
2362 0 : error = -EINVAL;
2363 0 : if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
2364 0 : goto out;
2365 :
2366 0 : error = flock_to_posix_lock(filp, fl, flock);
2367 0 : if (error)
2368 0 : goto out;
2369 :
2370 0 : if (cmd == F_OFD_GETLK) {
2371 0 : error = -EINVAL;
2372 0 : if (flock->l_pid != 0)
2373 0 : goto out;
2374 :
2375 0 : cmd = F_GETLK;
2376 0 : fl->fl_flags |= FL_OFDLCK;
2377 0 : fl->fl_owner = filp;
2378 : }
2379 :
2380 0 : error = vfs_test_lock(filp, fl);
2381 0 : if (error)
2382 0 : goto out;
2383 :
2384 0 : flock->l_type = fl->fl_type;
2385 0 : if (fl->fl_type != F_UNLCK) {
2386 0 : error = posix_lock_to_flock(flock, fl);
2387 0 : if (error)
2388 0 : goto out;
2389 : }
2390 0 : out:
2391 0 : locks_free_lock(fl);
2392 0 : return error;
2393 : }
2394 :
2395 : /**
2396 : * vfs_lock_file - file byte range lock
2397 : * @filp: The file to apply the lock to
2398 : * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2399 : * @fl: The lock to be applied
2400 : * @conf: Place to return a copy of the conflicting lock, if found.
2401 : *
2402 : * A caller that doesn't care about the conflicting lock may pass NULL
2403 : * as the final argument.
2404 : *
2405 : * If the filesystem defines a private ->lock() method, then @conf will
2406 : * be left unchanged; so a caller that cares should initialize it to
2407 : * some acceptable default.
2408 : *
2409 : * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2410 : * locks, the ->lock() interface may return asynchronously, before the lock has
2411 : * been granted or denied by the underlying filesystem, if (and only if)
2412 : * lm_grant is set. Callers expecting ->lock() to return asynchronously
2413 : * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2414 : * the request is for a blocking lock. When ->lock() does return asynchronously,
2415 : * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2416 : * request completes.
2417 : * If the request is for non-blocking lock the file system should return
2418 : * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2419 : * with the result. If the request timed out the callback routine will return a
2420 : * nonzero return code and the file system should release the lock. The file
2421 : * system is also responsible to keep a corresponding posix lock when it
2422 : * grants a lock so the VFS can find out which locks are locally held and do
2423 : * the correct lock cleanup when required.
2424 : * The underlying filesystem must not drop the kernel lock or call
2425 : * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2426 : * return code.
2427 : */
2428 134 : int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2429 : {
2430 134 : if (filp->f_op->lock)
2431 0 : return filp->f_op->lock(filp, cmd, fl);
2432 : else
2433 134 : return posix_lock_file(filp, fl, conf);
2434 : }
2435 : EXPORT_SYMBOL_GPL(vfs_lock_file);
2436 :
2437 90 : static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2438 : struct file_lock *fl)
2439 : {
2440 90 : int error;
2441 :
2442 90 : error = security_file_lock(filp, fl->fl_type);
2443 90 : if (error)
2444 : return error;
2445 :
2446 92 : for (;;) {
2447 184 : error = vfs_lock_file(filp, cmd, fl, NULL);
2448 92 : if (error != FILE_LOCK_DEFERRED)
2449 : break;
2450 96 : error = wait_event_interruptible(fl->fl_wait,
2451 : list_empty(&fl->fl_blocked_member));
2452 2 : if (error)
2453 : break;
2454 : }
2455 90 : locks_delete_block(fl);
2456 :
2457 90 : return error;
2458 : }
2459 :
2460 : /* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
2461 : static int
2462 90 : check_fmode_for_setlk(struct file_lock *fl)
2463 : {
2464 90 : switch (fl->fl_type) {
2465 33 : case F_RDLCK:
2466 33 : if (!(fl->fl_file->f_mode & FMODE_READ))
2467 0 : return -EBADF;
2468 : break;
2469 26 : case F_WRLCK:
2470 26 : if (!(fl->fl_file->f_mode & FMODE_WRITE))
2471 0 : return -EBADF;
2472 : }
2473 : return 0;
2474 : }
2475 :
2476 : /* Apply the lock described by l to an open file descriptor.
2477 : * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2478 : */
2479 90 : int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2480 : struct flock *flock)
2481 : {
2482 90 : struct file_lock *file_lock = locks_alloc_lock();
2483 90 : struct inode *inode = locks_inode(filp);
2484 90 : struct file *f;
2485 90 : int error;
2486 :
2487 90 : if (file_lock == NULL)
2488 : return -ENOLCK;
2489 :
2490 : /* Don't allow mandatory locks on files that may be memory mapped
2491 : * and shared.
2492 : */
2493 90 : if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2494 : error = -EAGAIN;
2495 : goto out;
2496 : }
2497 :
2498 90 : error = flock_to_posix_lock(filp, file_lock, flock);
2499 90 : if (error)
2500 0 : goto out;
2501 :
2502 90 : error = check_fmode_for_setlk(file_lock);
2503 90 : if (error)
2504 0 : goto out;
2505 :
2506 : /*
2507 : * If the cmd is requesting file-private locks, then set the
2508 : * FL_OFDLCK flag and override the owner.
2509 : */
2510 90 : switch (cmd) {
2511 0 : case F_OFD_SETLK:
2512 0 : error = -EINVAL;
2513 0 : if (flock->l_pid != 0)
2514 0 : goto out;
2515 :
2516 0 : cmd = F_SETLK;
2517 0 : file_lock->fl_flags |= FL_OFDLCK;
2518 0 : file_lock->fl_owner = filp;
2519 0 : break;
2520 0 : case F_OFD_SETLKW:
2521 0 : error = -EINVAL;
2522 0 : if (flock->l_pid != 0)
2523 0 : goto out;
2524 :
2525 0 : cmd = F_SETLKW;
2526 0 : file_lock->fl_flags |= FL_OFDLCK;
2527 0 : file_lock->fl_owner = filp;
2528 71 : fallthrough;
2529 71 : case F_SETLKW:
2530 71 : file_lock->fl_flags |= FL_SLEEP;
2531 : }
2532 :
2533 90 : error = do_lock_file_wait(filp, cmd, file_lock);
2534 :
2535 : /*
2536 : * Attempt to detect a close/fcntl race and recover by releasing the
2537 : * lock that was just acquired. There is no need to do that when we're
2538 : * unlocking though, or for OFD locks.
2539 : */
2540 90 : if (!error && file_lock->fl_type != F_UNLCK &&
2541 59 : !(file_lock->fl_flags & FL_OFDLCK)) {
2542 59 : struct files_struct *files = current->files;
2543 : /*
2544 : * We need that spin_lock here - it prevents reordering between
2545 : * update of i_flctx->flc_posix and check for it done in
2546 : * close(). rcu_read_lock() wouldn't do.
2547 : */
2548 59 : spin_lock(&files->file_lock);
2549 59 : f = files_lookup_fd_locked(files, fd);
2550 59 : spin_unlock(&files->file_lock);
2551 59 : if (f != filp) {
2552 0 : file_lock->fl_type = F_UNLCK;
2553 0 : error = do_lock_file_wait(filp, cmd, file_lock);
2554 0 : WARN_ON_ONCE(error);
2555 : error = -EBADF;
2556 : }
2557 : }
2558 90 : out:
2559 90 : trace_fcntl_setlk(inode, file_lock, error);
2560 90 : locks_free_lock(file_lock);
2561 90 : return error;
2562 : }
2563 :
2564 : #if BITS_PER_LONG == 32
2565 : /* Report the first existing lock that would conflict with l.
2566 : * This implements the F_GETLK command of fcntl().
2567 : */
2568 : int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
2569 : {
2570 : struct file_lock *fl;
2571 : int error;
2572 :
2573 : fl = locks_alloc_lock();
2574 : if (fl == NULL)
2575 : return -ENOMEM;
2576 :
2577 : error = -EINVAL;
2578 : if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
2579 : goto out;
2580 :
2581 : error = flock64_to_posix_lock(filp, fl, flock);
2582 : if (error)
2583 : goto out;
2584 :
2585 : if (cmd == F_OFD_GETLK) {
2586 : error = -EINVAL;
2587 : if (flock->l_pid != 0)
2588 : goto out;
2589 :
2590 : cmd = F_GETLK64;
2591 : fl->fl_flags |= FL_OFDLCK;
2592 : fl->fl_owner = filp;
2593 : }
2594 :
2595 : error = vfs_test_lock(filp, fl);
2596 : if (error)
2597 : goto out;
2598 :
2599 : flock->l_type = fl->fl_type;
2600 : if (fl->fl_type != F_UNLCK)
2601 : posix_lock_to_flock64(flock, fl);
2602 :
2603 : out:
2604 : locks_free_lock(fl);
2605 : return error;
2606 : }
2607 :
2608 : /* Apply the lock described by l to an open file descriptor.
2609 : * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2610 : */
2611 : int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2612 : struct flock64 *flock)
2613 : {
2614 : struct file_lock *file_lock = locks_alloc_lock();
2615 : struct inode *inode = locks_inode(filp);
2616 : struct file *f;
2617 : int error;
2618 :
2619 : if (file_lock == NULL)
2620 : return -ENOLCK;
2621 :
2622 : /* Don't allow mandatory locks on files that may be memory mapped
2623 : * and shared.
2624 : */
2625 : if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2626 : error = -EAGAIN;
2627 : goto out;
2628 : }
2629 :
2630 : error = flock64_to_posix_lock(filp, file_lock, flock);
2631 : if (error)
2632 : goto out;
2633 :
2634 : error = check_fmode_for_setlk(file_lock);
2635 : if (error)
2636 : goto out;
2637 :
2638 : /*
2639 : * If the cmd is requesting file-private locks, then set the
2640 : * FL_OFDLCK flag and override the owner.
2641 : */
2642 : switch (cmd) {
2643 : case F_OFD_SETLK:
2644 : error = -EINVAL;
2645 : if (flock->l_pid != 0)
2646 : goto out;
2647 :
2648 : cmd = F_SETLK64;
2649 : file_lock->fl_flags |= FL_OFDLCK;
2650 : file_lock->fl_owner = filp;
2651 : break;
2652 : case F_OFD_SETLKW:
2653 : error = -EINVAL;
2654 : if (flock->l_pid != 0)
2655 : goto out;
2656 :
2657 : cmd = F_SETLKW64;
2658 : file_lock->fl_flags |= FL_OFDLCK;
2659 : file_lock->fl_owner = filp;
2660 : fallthrough;
2661 : case F_SETLKW64:
2662 : file_lock->fl_flags |= FL_SLEEP;
2663 : }
2664 :
2665 : error = do_lock_file_wait(filp, cmd, file_lock);
2666 :
2667 : /*
2668 : * Attempt to detect a close/fcntl race and recover by releasing the
2669 : * lock that was just acquired. There is no need to do that when we're
2670 : * unlocking though, or for OFD locks.
2671 : */
2672 : if (!error && file_lock->fl_type != F_UNLCK &&
2673 : !(file_lock->fl_flags & FL_OFDLCK)) {
2674 : struct files_struct *files = current->files;
2675 : /*
2676 : * We need that spin_lock here - it prevents reordering between
2677 : * update of i_flctx->flc_posix and check for it done in
2678 : * close(). rcu_read_lock() wouldn't do.
2679 : */
2680 : spin_lock(&files->file_lock);
2681 : f = files_lookup_fd_locked(files, fd);
2682 : spin_unlock(&files->file_lock);
2683 : if (f != filp) {
2684 : file_lock->fl_type = F_UNLCK;
2685 : error = do_lock_file_wait(filp, cmd, file_lock);
2686 : WARN_ON_ONCE(error);
2687 : error = -EBADF;
2688 : }
2689 : }
2690 : out:
2691 : locks_free_lock(file_lock);
2692 : return error;
2693 : }
2694 : #endif /* BITS_PER_LONG == 32 */
2695 :
2696 : /*
2697 : * This function is called when the file is being removed
2698 : * from the task's fd array. POSIX locks belonging to this task
2699 : * are deleted at this time.
2700 : */
2701 29535 : void locks_remove_posix(struct file *filp, fl_owner_t owner)
2702 : {
2703 29535 : int error;
2704 29535 : struct inode *inode = locks_inode(filp);
2705 29535 : struct file_lock lock;
2706 29535 : struct file_lock_context *ctx;
2707 :
2708 : /*
2709 : * If there are no locks held on this file, we don't need to call
2710 : * posix_lock_file(). Another process could be setting a lock on this
2711 : * file at the same time, but we wouldn't remove that lock anyway.
2712 : */
2713 29535 : ctx = smp_load_acquire(&inode->i_flctx);
2714 29537 : if (!ctx || list_empty(&ctx->flc_posix))
2715 29495 : return;
2716 :
2717 42 : locks_init_lock(&lock);
2718 42 : lock.fl_type = F_UNLCK;
2719 42 : lock.fl_flags = FL_POSIX | FL_CLOSE;
2720 42 : lock.fl_start = 0;
2721 42 : lock.fl_end = OFFSET_MAX;
2722 42 : lock.fl_owner = owner;
2723 42 : lock.fl_pid = current->tgid;
2724 42 : lock.fl_file = filp;
2725 42 : lock.fl_ops = NULL;
2726 42 : lock.fl_lmops = NULL;
2727 :
2728 42 : error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
2729 :
2730 42 : if (lock.fl_ops && lock.fl_ops->fl_release_private)
2731 0 : lock.fl_ops->fl_release_private(&lock);
2732 42 : trace_locks_remove_posix(inode, &lock, error);
2733 : }
2734 : EXPORT_SYMBOL(locks_remove_posix);
2735 :
2736 : /* The i_flctx must be valid when calling into here */
2737 : static void
2738 178 : locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
2739 : {
2740 178 : struct file_lock fl;
2741 178 : struct inode *inode = locks_inode(filp);
2742 :
2743 178 : if (list_empty(&flctx->flc_flock))
2744 101 : return;
2745 :
2746 77 : flock_make_lock(filp, LOCK_UN, &fl);
2747 77 : fl.fl_flags |= FL_CLOSE;
2748 :
2749 77 : if (filp->f_op->flock)
2750 0 : filp->f_op->flock(filp, F_SETLKW, &fl);
2751 : else
2752 77 : flock_lock_inode(inode, &fl);
2753 :
2754 77 : if (fl.fl_ops && fl.fl_ops->fl_release_private)
2755 0 : fl.fl_ops->fl_release_private(&fl);
2756 : }
2757 :
2758 : /* The i_flctx must be valid when calling into here */
2759 : static void
2760 178 : locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
2761 : {
2762 178 : struct file_lock *fl, *tmp;
2763 178 : LIST_HEAD(dispose);
2764 :
2765 178 : if (list_empty(&ctx->flc_lease))
2766 178 : return;
2767 :
2768 0 : percpu_down_read(&file_rwsem);
2769 0 : spin_lock(&ctx->flc_lock);
2770 0 : list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
2771 0 : if (filp == fl->fl_file)
2772 0 : lease_modify(fl, F_UNLCK, &dispose);
2773 0 : spin_unlock(&ctx->flc_lock);
2774 0 : percpu_up_read(&file_rwsem);
2775 :
2776 0 : locks_dispose_list(&dispose);
2777 : }
2778 :
2779 : /*
2780 : * This function is called on the last close of an open file.
2781 : */
2782 47140 : void locks_remove_file(struct file *filp)
2783 : {
2784 47140 : struct file_lock_context *ctx;
2785 :
2786 47140 : ctx = smp_load_acquire(&locks_inode(filp)->i_flctx);
2787 47155 : if (!ctx)
2788 : return;
2789 :
2790 : /* remove any OFD locks */
2791 178 : locks_remove_posix(filp, filp);
2792 :
2793 : /* remove flock locks */
2794 178 : locks_remove_flock(filp, ctx);
2795 :
2796 : /* remove any leases */
2797 178 : locks_remove_lease(filp, ctx);
2798 :
2799 178 : spin_lock(&ctx->flc_lock);
2800 178 : locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX");
2801 178 : locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK");
2802 178 : locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE");
2803 178 : spin_unlock(&ctx->flc_lock);
2804 : }
2805 :
2806 : /**
2807 : * vfs_cancel_lock - file byte range unblock lock
2808 : * @filp: The file to apply the unblock to
2809 : * @fl: The lock to be unblocked
2810 : *
2811 : * Used by lock managers to cancel blocked requests
2812 : */
2813 0 : int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2814 : {
2815 0 : if (filp->f_op->lock)
2816 0 : return filp->f_op->lock(filp, F_CANCELLK, fl);
2817 : return 0;
2818 : }
2819 : EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2820 :
2821 : #ifdef CONFIG_PROC_FS
2822 : #include <linux/proc_fs.h>
2823 : #include <linux/seq_file.h>
2824 :
2825 : struct locks_iterator {
2826 : int li_cpu;
2827 : loff_t li_pos;
2828 : };
2829 :
2830 0 : static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2831 : loff_t id, char *pfx)
2832 : {
2833 0 : struct inode *inode = NULL;
2834 0 : unsigned int fl_pid;
2835 0 : struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
2836 :
2837 0 : fl_pid = locks_translate_pid(fl, proc_pidns);
2838 : /*
2839 : * If lock owner is dead (and pid is freed) or not visible in current
2840 : * pidns, zero is shown as a pid value. Check lock info from
2841 : * init_pid_ns to get saved lock pid value.
2842 : */
2843 :
2844 0 : if (fl->fl_file != NULL)
2845 0 : inode = locks_inode(fl->fl_file);
2846 :
2847 0 : seq_printf(f, "%lld:%s ", id, pfx);
2848 0 : if (IS_POSIX(fl)) {
2849 0 : if (fl->fl_flags & FL_ACCESS)
2850 0 : seq_puts(f, "ACCESS");
2851 0 : else if (IS_OFDLCK(fl))
2852 0 : seq_puts(f, "OFDLCK");
2853 : else
2854 0 : seq_puts(f, "POSIX ");
2855 :
2856 0 : seq_printf(f, " %s ",
2857 : (inode == NULL) ? "*NOINODE*" :
2858 0 : mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2859 0 : } else if (IS_FLOCK(fl)) {
2860 0 : if (fl->fl_type & LOCK_MAND) {
2861 0 : seq_puts(f, "FLOCK MSNFS ");
2862 : } else {
2863 0 : seq_puts(f, "FLOCK ADVISORY ");
2864 : }
2865 0 : } else if (IS_LEASE(fl)) {
2866 0 : if (fl->fl_flags & FL_DELEG)
2867 0 : seq_puts(f, "DELEG ");
2868 : else
2869 0 : seq_puts(f, "LEASE ");
2870 :
2871 0 : if (lease_breaking(fl))
2872 0 : seq_puts(f, "BREAKING ");
2873 0 : else if (fl->fl_file)
2874 0 : seq_puts(f, "ACTIVE ");
2875 : else
2876 0 : seq_puts(f, "BREAKER ");
2877 : } else {
2878 0 : seq_puts(f, "UNKNOWN UNKNOWN ");
2879 : }
2880 0 : if (fl->fl_type & LOCK_MAND) {
2881 0 : seq_printf(f, "%s ",
2882 : (fl->fl_type & LOCK_READ)
2883 0 : ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2884 0 : : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2885 : } else {
2886 0 : int type = IS_LEASE(fl) ? target_leasetype(fl) : fl->fl_type;
2887 :
2888 0 : seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" :
2889 0 : (type == F_RDLCK) ? "READ" : "UNLCK");
2890 : }
2891 0 : if (inode) {
2892 : /* userspace relies on this representation of dev_t */
2893 0 : seq_printf(f, "%d %02x:%02x:%lu ", fl_pid,
2894 0 : MAJOR(inode->i_sb->s_dev),
2895 0 : MINOR(inode->i_sb->s_dev), inode->i_ino);
2896 : } else {
2897 0 : seq_printf(f, "%d <none>:0 ", fl_pid);
2898 : }
2899 0 : if (IS_POSIX(fl)) {
2900 0 : if (fl->fl_end == OFFSET_MAX)
2901 0 : seq_printf(f, "%Ld EOF\n", fl->fl_start);
2902 : else
2903 0 : seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2904 : } else {
2905 0 : seq_puts(f, "0 EOF\n");
2906 : }
2907 0 : }
2908 :
2909 0 : static int locks_show(struct seq_file *f, void *v)
2910 : {
2911 0 : struct locks_iterator *iter = f->private;
2912 0 : struct file_lock *fl, *bfl;
2913 0 : struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
2914 :
2915 0 : fl = hlist_entry(v, struct file_lock, fl_link);
2916 :
2917 0 : if (locks_translate_pid(fl, proc_pidns) == 0)
2918 : return 0;
2919 :
2920 0 : lock_get_status(f, fl, iter->li_pos, "");
2921 :
2922 0 : list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member)
2923 0 : lock_get_status(f, bfl, iter->li_pos, " ->");
2924 :
2925 : return 0;
2926 : }
2927 :
2928 0 : static void __show_fd_locks(struct seq_file *f,
2929 : struct list_head *head, int *id,
2930 : struct file *filp, struct files_struct *files)
2931 : {
2932 0 : struct file_lock *fl;
2933 :
2934 0 : list_for_each_entry(fl, head, fl_list) {
2935 :
2936 0 : if (filp != fl->fl_file)
2937 0 : continue;
2938 0 : if (fl->fl_owner != files &&
2939 : fl->fl_owner != filp)
2940 0 : continue;
2941 :
2942 0 : (*id)++;
2943 0 : seq_puts(f, "lock:\t");
2944 0 : lock_get_status(f, fl, *id, "");
2945 : }
2946 0 : }
2947 :
2948 139 : void show_fd_locks(struct seq_file *f,
2949 : struct file *filp, struct files_struct *files)
2950 : {
2951 139 : struct inode *inode = locks_inode(filp);
2952 139 : struct file_lock_context *ctx;
2953 139 : int id = 0;
2954 :
2955 139 : ctx = smp_load_acquire(&inode->i_flctx);
2956 139 : if (!ctx)
2957 139 : return;
2958 :
2959 0 : spin_lock(&ctx->flc_lock);
2960 0 : __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2961 0 : __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2962 0 : __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2963 0 : spin_unlock(&ctx->flc_lock);
2964 : }
2965 :
2966 0 : static void *locks_start(struct seq_file *f, loff_t *pos)
2967 : __acquires(&blocked_lock_lock)
2968 : {
2969 0 : struct locks_iterator *iter = f->private;
2970 :
2971 0 : iter->li_pos = *pos + 1;
2972 0 : percpu_down_write(&file_rwsem);
2973 0 : spin_lock(&blocked_lock_lock);
2974 0 : return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
2975 : }
2976 :
2977 0 : static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2978 : {
2979 0 : struct locks_iterator *iter = f->private;
2980 :
2981 0 : ++iter->li_pos;
2982 0 : return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
2983 : }
2984 :
2985 0 : static void locks_stop(struct seq_file *f, void *v)
2986 : __releases(&blocked_lock_lock)
2987 : {
2988 0 : spin_unlock(&blocked_lock_lock);
2989 0 : percpu_up_write(&file_rwsem);
2990 0 : }
2991 :
2992 : static const struct seq_operations locks_seq_operations = {
2993 : .start = locks_start,
2994 : .next = locks_next,
2995 : .stop = locks_stop,
2996 : .show = locks_show,
2997 : };
2998 :
2999 1 : static int __init proc_locks_init(void)
3000 : {
3001 1 : proc_create_seq_private("locks", 0, NULL, &locks_seq_operations,
3002 : sizeof(struct locks_iterator), NULL);
3003 1 : return 0;
3004 : }
3005 : fs_initcall(proc_locks_init);
3006 : #endif
3007 :
3008 1 : static int __init filelock_init(void)
3009 : {
3010 1 : int i;
3011 :
3012 1 : flctx_cache = kmem_cache_create("file_lock_ctx",
3013 : sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
3014 :
3015 1 : filelock_cache = kmem_cache_create("file_lock_cache",
3016 : sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
3017 :
3018 5 : for_each_possible_cpu(i) {
3019 4 : struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
3020 :
3021 4 : spin_lock_init(&fll->lock);
3022 4 : INIT_HLIST_HEAD(&fll->hlist);
3023 : }
3024 :
3025 1 : lease_notifier_chain_init();
3026 1 : return 0;
3027 : }
3028 : core_initcall(filelock_init);
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