Branch data Line data Source code
1 : : /*
2 : : * linux/fs/locks.c
3 : : *
4 : : * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
5 : : * Doug Evans (dje@spiff.uucp), August 07, 1992
6 : : *
7 : : * Deadlock detection added.
8 : : * FIXME: one thing isn't handled yet:
9 : : * - mandatory locks (requires lots of changes elsewhere)
10 : : * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
11 : : *
12 : : * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
13 : : * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
14 : : *
15 : : * Converted file_lock_table to a linked list from an array, which eliminates
16 : : * the limits on how many active file locks are open.
17 : : * Chad Page (pageone@netcom.com), November 27, 1994
18 : : *
19 : : * Removed dependency on file descriptors. dup()'ed file descriptors now
20 : : * get the same locks as the original file descriptors, and a close() on
21 : : * any file descriptor removes ALL the locks on the file for the current
22 : : * process. Since locks still depend on the process id, locks are inherited
23 : : * after an exec() but not after a fork(). This agrees with POSIX, and both
24 : : * BSD and SVR4 practice.
25 : : * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
26 : : *
27 : : * Scrapped free list which is redundant now that we allocate locks
28 : : * dynamically with kmalloc()/kfree().
29 : : * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
30 : : *
31 : : * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
32 : : *
33 : : * FL_POSIX locks are created with calls to fcntl() and lockf() through the
34 : : * fcntl() system call. They have the semantics described above.
35 : : *
36 : : * FL_FLOCK locks are created with calls to flock(), through the flock()
37 : : * system call, which is new. Old C libraries implement flock() via fcntl()
38 : : * and will continue to use the old, broken implementation.
39 : : *
40 : : * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
41 : : * with a file pointer (filp). As a result they can be shared by a parent
42 : : * process and its children after a fork(). They are removed when the last
43 : : * file descriptor referring to the file pointer is closed (unless explicitly
44 : : * unlocked).
45 : : *
46 : : * FL_FLOCK locks never deadlock, an existing lock is always removed before
47 : : * upgrading from shared to exclusive (or vice versa). When this happens
48 : : * any processes blocked by the current lock are woken up and allowed to
49 : : * run before the new lock is applied.
50 : : * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
51 : : *
52 : : * Removed some race conditions in flock_lock_file(), marked other possible
53 : : * races. Just grep for FIXME to see them.
54 : : * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
55 : : *
56 : : * Addressed Dmitry's concerns. Deadlock checking no longer recursive.
57 : : * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
58 : : * once we've checked for blocking and deadlocking.
59 : : * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
60 : : *
61 : : * Initial implementation of mandatory locks. SunOS turned out to be
62 : : * a rotten model, so I implemented the "obvious" semantics.
63 : : * See 'Documentation/filesystems/mandatory-locking.txt' for details.
64 : : * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
65 : : *
66 : : * Don't allow mandatory locks on mmap()'ed files. Added simple functions to
67 : : * check if a file has mandatory locks, used by mmap(), open() and creat() to
68 : : * see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
69 : : * Manual, Section 2.
70 : : * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
71 : : *
72 : : * Tidied up block list handling. Added '/proc/locks' interface.
73 : : * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
74 : : *
75 : : * Fixed deadlock condition for pathological code that mixes calls to
76 : : * flock() and fcntl().
77 : : * Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
78 : : *
79 : : * Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
80 : : * for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
81 : : * guarantee sensible behaviour in the case where file system modules might
82 : : * be compiled with different options than the kernel itself.
83 : : * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
84 : : *
85 : : * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
86 : : * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
87 : : * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
88 : : *
89 : : * Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
90 : : * locks. Changed process synchronisation to avoid dereferencing locks that
91 : : * have already been freed.
92 : : * Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
93 : : *
94 : : * Made the block list a circular list to minimise searching in the list.
95 : : * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
96 : : *
97 : : * Made mandatory locking a mount option. Default is not to allow mandatory
98 : : * locking.
99 : : * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
100 : : *
101 : : * Some adaptations for NFS support.
102 : : * Olaf Kirch (okir@monad.swb.de), Dec 1996,
103 : : *
104 : : * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
105 : : * Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
106 : : *
107 : : * Use slab allocator instead of kmalloc/kfree.
108 : : * Use generic list implementation from <linux/list.h>.
109 : : * Sped up posix_locks_deadlock by only considering blocked locks.
110 : : * Matthew Wilcox <willy@debian.org>, March, 2000.
111 : : *
112 : : * Leases and LOCK_MAND
113 : : * Matthew Wilcox <willy@debian.org>, June, 2000.
114 : : * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
115 : : */
116 : :
117 : : #include <linux/capability.h>
118 : : #include <linux/file.h>
119 : : #include <linux/fdtable.h>
120 : : #include <linux/fs.h>
121 : : #include <linux/init.h>
122 : : #include <linux/module.h>
123 : : #include <linux/security.h>
124 : : #include <linux/slab.h>
125 : : #include <linux/syscalls.h>
126 : : #include <linux/time.h>
127 : : #include <linux/rcupdate.h>
128 : : #include <linux/pid_namespace.h>
129 : : #include <linux/hashtable.h>
130 : : #include <linux/percpu.h>
131 : : #include <linux/lglock.h>
132 : :
133 : : #include <asm/uaccess.h>
134 : :
135 : : #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
136 : : #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
137 : : #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG))
138 : :
139 : : static bool lease_breaking(struct file_lock *fl)
140 : : {
141 : 21 : return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
142 : : }
143 : :
144 : : static int target_leasetype(struct file_lock *fl)
145 : : {
146 [ + - ]: 8 : if (fl->fl_flags & FL_UNLOCK_PENDING)
147 : : return F_UNLCK;
148 [ + - ]: 8 : if (fl->fl_flags & FL_DOWNGRADE_PENDING)
149 : : return F_RDLCK;
150 : 8 : return fl->fl_type;
151 : : }
152 : :
153 : : int leases_enable = 1;
154 : : int lease_break_time = 45;
155 : :
156 : : #define for_each_lock(inode, lockp) \
157 : : for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
158 : :
159 : : /*
160 : : * The global file_lock_list is only used for displaying /proc/locks, so we
161 : : * keep a list on each CPU, with each list protected by its own spinlock via
162 : : * the file_lock_lglock. Note that alterations to the list also require that
163 : : * the relevant i_lock is held.
164 : : */
165 : : DEFINE_STATIC_LGLOCK(file_lock_lglock);
166 : : static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
167 : :
168 : : /*
169 : : * The blocked_hash is used to find POSIX lock loops for deadlock detection.
170 : : * It is protected by blocked_lock_lock.
171 : : *
172 : : * We hash locks by lockowner in order to optimize searching for the lock a
173 : : * particular lockowner is waiting on.
174 : : *
175 : : * FIXME: make this value scale via some heuristic? We generally will want more
176 : : * buckets when we have more lockowners holding locks, but that's a little
177 : : * difficult to determine without knowing what the workload will look like.
178 : : */
179 : : #define BLOCKED_HASH_BITS 7
180 : : static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
181 : :
182 : : /*
183 : : * This lock protects the blocked_hash. Generally, if you're accessing it, you
184 : : * want to be holding this lock.
185 : : *
186 : : * In addition, it also protects the fl->fl_block list, and the fl->fl_next
187 : : * pointer for file_lock structures that are acting as lock requests (in
188 : : * contrast to those that are acting as records of acquired locks).
189 : : *
190 : : * Note that when we acquire this lock in order to change the above fields,
191 : : * we often hold the i_lock as well. In certain cases, when reading the fields
192 : : * protected by this lock, we can skip acquiring it iff we already hold the
193 : : * i_lock.
194 : : *
195 : : * In particular, adding an entry to the fl_block list requires that you hold
196 : : * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting
197 : : * an entry from the list however only requires the file_lock_lock.
198 : : */
199 : : static DEFINE_SPINLOCK(blocked_lock_lock);
200 : :
201 : : static struct kmem_cache *filelock_cache __read_mostly;
202 : :
203 : : static void locks_init_lock_heads(struct file_lock *fl)
204 : : {
205 : : INIT_HLIST_NODE(&fl->fl_link);
206 : 4323927 : INIT_LIST_HEAD(&fl->fl_block);
207 : 4323927 : init_waitqueue_head(&fl->fl_wait);
208 : : }
209 : :
210 : : /* Allocate an empty lock structure. */
211 : 0 : struct file_lock *locks_alloc_lock(void)
212 : : {
213 : 4323142 : struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
214 : :
215 [ + ]: 4323886 : if (fl)
216 : : locks_init_lock_heads(fl);
217 : :
218 : 854 : return fl;
219 : : }
220 : : EXPORT_SYMBOL_GPL(locks_alloc_lock);
221 : :
222 : 0 : void locks_release_private(struct file_lock *fl)
223 : : {
224 [ - + ][ - + ]: 5393165 : if (fl->fl_ops) {
[ - + ][ # # ]
225 [ # # ][ # # ]: 0 : if (fl->fl_ops->fl_release_private)
[ # # ][ # # ]
226 : 0 : fl->fl_ops->fl_release_private(fl);
227 : 0 : fl->fl_ops = NULL;
228 : : }
229 : 12 : fl->fl_lmops = NULL;
230 : :
231 : 0 : }
232 : : EXPORT_SYMBOL_GPL(locks_release_private);
233 : :
234 : : /* Free a lock which is not in use. */
235 : 0 : void locks_free_lock(struct file_lock *fl)
236 : : {
237 [ - + ]: 4324432 : BUG_ON(waitqueue_active(&fl->fl_wait));
238 [ - + ]: 4324432 : BUG_ON(!list_empty(&fl->fl_block));
239 [ - + ]: 4324432 : BUG_ON(!hlist_unhashed(&fl->fl_link));
240 : :
241 : : locks_release_private(fl);
242 : 4324432 : kmem_cache_free(filelock_cache, fl);
243 : 4324341 : }
244 : : EXPORT_SYMBOL(locks_free_lock);
245 : :
246 : 0 : void locks_init_lock(struct file_lock *fl)
247 : : {
248 : 30 : memset(fl, 0, sizeof(struct file_lock));
249 : : locks_init_lock_heads(fl);
250 : 30 : }
251 : :
252 : : EXPORT_SYMBOL(locks_init_lock);
253 : :
254 : 0 : static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
255 : : {
256 [ - + ]: 1068733 : if (fl->fl_ops) {
257 [ # # ]: 0 : if (fl->fl_ops->fl_copy_lock)
258 : 0 : fl->fl_ops->fl_copy_lock(new, fl);
259 : 0 : new->fl_ops = fl->fl_ops;
260 : : }
261 [ - + ]: 1068733 : if (fl->fl_lmops)
262 : 0 : new->fl_lmops = fl->fl_lmops;
263 : 0 : }
264 : :
265 : : /*
266 : : * Initialize a new lock from an existing file_lock structure.
267 : : */
268 : 0 : void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
269 : : {
270 : 428 : new->fl_owner = fl->fl_owner;
271 : 428 : new->fl_pid = fl->fl_pid;
272 : 428 : new->fl_file = NULL;
273 : 428 : new->fl_flags = fl->fl_flags;
274 : 428 : new->fl_type = fl->fl_type;
275 : 428 : new->fl_start = fl->fl_start;
276 : 428 : new->fl_end = fl->fl_end;
277 : 428 : new->fl_ops = NULL;
278 : 0 : new->fl_lmops = NULL;
279 : 0 : }
280 : : EXPORT_SYMBOL(__locks_copy_lock);
281 : :
282 : 0 : void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
283 : : {
284 : : locks_release_private(new);
285 : :
286 : : __locks_copy_lock(new, fl);
287 : 0 : new->fl_file = fl->fl_file;
288 : 0 : new->fl_ops = fl->fl_ops;
289 : 0 : new->fl_lmops = fl->fl_lmops;
290 : :
291 : 1068721 : locks_copy_private(new, fl);
292 : 1068715 : }
293 : :
294 : : EXPORT_SYMBOL(locks_copy_lock);
295 : :
296 : : static inline int flock_translate_cmd(int cmd) {
297 [ - + ]: 84 : if (cmd & LOCK_MAND)
298 [ + + ]: 84 : return cmd & (LOCK_MAND | LOCK_RW);
299 : : switch (cmd) {
300 : : case LOCK_SH:
301 : : return F_RDLCK;
302 : : case LOCK_EX:
303 : : return F_WRLCK;
304 : : case LOCK_UN:
305 : : return F_UNLCK;
306 : : }
307 : : return -EINVAL;
308 : : }
309 : :
310 : : /* Fill in a file_lock structure with an appropriate FLOCK lock. */
311 : 0 : static int flock_make_lock(struct file *filp, struct file_lock **lock,
312 : : unsigned int cmd)
313 : : {
314 : : struct file_lock *fl;
315 : 84 : int type = flock_translate_cmd(cmd);
316 [ + + ]: 84 : if (type < 0)
317 : : return type;
318 : :
319 : 82 : fl = locks_alloc_lock();
320 [ + - ]: 82 : if (fl == NULL)
321 : : return -ENOMEM;
322 : :
323 : 82 : fl->fl_file = filp;
324 : 82 : fl->fl_pid = current->tgid;
325 : 82 : fl->fl_flags = FL_FLOCK;
326 : 82 : fl->fl_type = type;
327 : 82 : fl->fl_end = OFFSET_MAX;
328 : :
329 : 82 : *lock = fl;
330 : 82 : return 0;
331 : : }
332 : :
333 : : static int assign_type(struct file_lock *fl, long type)
334 : : {
335 [ + - ][ + + ]: 2151911 : switch (type) {
[ + - ][ + + ]
336 : : case F_RDLCK:
337 : : case F_WRLCK:
338 : : case F_UNLCK:
339 : 2151901 : fl->fl_type = type;
340 : : break;
341 : : default:
342 : : return -EINVAL;
343 : : }
344 : : return 0;
345 : : }
346 : :
347 : : /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
348 : : * style lock.
349 : : */
350 : 0 : static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
351 : : struct flock *l)
352 : : {
353 : : off_t start, end;
354 : :
355 [ + - + + ]: 2125915 : switch (l->l_whence) {
356 : : case SEEK_SET:
357 : : start = 0;
358 : : break;
359 : : case SEEK_CUR:
360 : 38 : start = filp->f_pos;
361 : 38 : break;
362 : : case SEEK_END:
363 : 0 : start = i_size_read(file_inode(filp));
364 : 0 : break;
365 : : default:
366 : : return -EINVAL;
367 : : }
368 : :
369 : : /* POSIX-1996 leaves the case l->l_len < 0 undefined;
370 : : POSIX-2001 defines it. */
371 : 2125910 : start += l->l_start;
372 [ + - ]: 2125910 : if (start < 0)
373 : : return -EINVAL;
374 : 2125910 : fl->fl_end = OFFSET_MAX;
375 [ + + ]: 2125910 : if (l->l_len > 0) {
376 : 34340 : end = start + l->l_len - 1;
377 : 34340 : fl->fl_end = end;
378 [ - + ]: 2091570 : } else if (l->l_len < 0) {
379 : 0 : end = start - 1;
380 : 0 : fl->fl_end = end;
381 : 0 : start += l->l_len;
382 [ # # ]: 0 : if (start < 0)
383 : : return -EINVAL;
384 : : }
385 : 2125913 : fl->fl_start = start; /* we record the absolute position */
386 [ + - ]: 4251828 : if (fl->fl_end < fl->fl_start)
387 : : return -EOVERFLOW;
388 : :
389 : 2125913 : fl->fl_owner = current->files;
390 : 2125913 : fl->fl_pid = current->tgid;
391 : 2125913 : fl->fl_file = filp;
392 : 2125913 : fl->fl_flags = FL_POSIX;
393 : 2125913 : fl->fl_ops = NULL;
394 : 2125913 : fl->fl_lmops = NULL;
395 : :
396 : 2125913 : return assign_type(fl, l->l_type);
397 : : }
398 : :
399 : : #if BITS_PER_LONG == 32
400 : 0 : static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
401 : : struct flock64 *l)
402 : : {
403 : : loff_t start;
404 : :
405 [ + - + + ]: 6441 : switch (l->l_whence) {
406 : : case SEEK_SET:
407 : : start = 0;
408 : : break;
409 : : case SEEK_CUR:
410 : 32 : start = filp->f_pos;
411 : 32 : break;
412 : : case SEEK_END:
413 : : start = i_size_read(file_inode(filp));
414 : : break;
415 : : default:
416 : : return -EINVAL;
417 : : }
418 : :
419 : 6439 : start += l->l_start;
420 [ + - ]: 6439 : if (start < 0)
421 : : return -EINVAL;
422 : 6439 : fl->fl_end = OFFSET_MAX;
423 [ + + ]: 6439 : if (l->l_len > 0) {
424 : 360 : fl->fl_end = start + l->l_len - 1;
425 [ - + ]: 6079 : } else if (l->l_len < 0) {
426 : 0 : fl->fl_end = start - 1;
427 : 0 : start += l->l_len;
428 [ # # ]: 0 : if (start < 0)
429 : : return -EINVAL;
430 : : }
431 : 6439 : fl->fl_start = start; /* we record the absolute position */
432 [ + - ]: 12880 : if (fl->fl_end < fl->fl_start)
433 : : return -EOVERFLOW;
434 : :
435 : 6439 : fl->fl_owner = current->files;
436 : 6439 : fl->fl_pid = current->tgid;
437 : 6439 : fl->fl_file = filp;
438 : 6439 : fl->fl_flags = FL_POSIX;
439 : 6439 : fl->fl_ops = NULL;
440 : 6439 : fl->fl_lmops = NULL;
441 : :
442 : 6439 : return assign_type(fl, l->l_type);
443 : : }
444 : : #endif
445 : :
446 : : /* default lease lock manager operations */
447 : 0 : static void lease_break_callback(struct file_lock *fl)
448 : : {
449 : 0 : kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
450 : 0 : }
451 : :
452 : : static const struct lock_manager_operations lease_manager_ops = {
453 : : .lm_break = lease_break_callback,
454 : : .lm_change = lease_modify,
455 : : };
456 : :
457 : : /*
458 : : * Initialize a lease, use the default lock manager operations
459 : : */
460 : 0 : static int lease_init(struct file *filp, long type, struct file_lock *fl)
461 : : {
462 [ + ]: 19551 : if (assign_type(fl, type) != 0)
463 : : return -EINVAL;
464 : :
465 : 19550 : fl->fl_owner = current->files;
466 : 19550 : fl->fl_pid = current->tgid;
467 : :
468 : 19550 : fl->fl_file = filp;
469 : 19550 : fl->fl_flags = FL_LEASE;
470 : 19550 : fl->fl_start = 0;
471 : 19550 : fl->fl_end = OFFSET_MAX;
472 : 19550 : fl->fl_ops = NULL;
473 : 19550 : fl->fl_lmops = &lease_manager_ops;
474 : 19550 : return 0;
475 : : }
476 : :
477 : : /* Allocate a file_lock initialised to this type of lease */
478 : 0 : static struct file_lock *lease_alloc(struct file *filp, long type)
479 : : {
480 : 19543 : struct file_lock *fl = locks_alloc_lock();
481 : : int error = -ENOMEM;
482 : :
483 [ + - ]: 19543 : if (fl == NULL)
484 : : return ERR_PTR(error);
485 : :
486 : 19543 : error = lease_init(filp, type, fl);
487 [ - + ]: 19542 : if (error) {
488 : 0 : locks_free_lock(fl);
489 : 0 : return ERR_PTR(error);
490 : : }
491 : : return fl;
492 : : }
493 : :
494 : : /* Check if two locks overlap each other.
495 : : */
496 : : static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
497 : : {
498 [ + + ][ + + ]: 34021 : return ((fl1->fl_end >= fl2->fl_start) &&
499 : 31890 : (fl2->fl_end >= fl1->fl_start));
500 : : }
501 : :
502 : : /*
503 : : * Check whether two locks have the same owner.
504 : : */
505 : 0 : static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
506 : : {
507 [ - + ][ # # ]: 2204460 : if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
508 [ # # # # ]: 0 : return fl2->fl_lmops == fl1->fl_lmops &&
509 : 0 : fl1->fl_lmops->lm_compare_owner(fl1, fl2);
510 : 2204460 : return fl1->fl_owner == fl2->fl_owner;
511 : : }
512 : :
513 : : /* Must be called with the i_lock held! */
514 : : static inline void
515 : : locks_insert_global_locks(struct file_lock *fl)
516 : : {
517 : 1068724 : lg_local_lock(&file_lock_lglock);
518 : 1068729 : fl->fl_link_cpu = smp_processor_id();
519 : 2137458 : hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
520 : 1068729 : lg_local_unlock(&file_lock_lglock);
521 : : }
522 : :
523 : : /* Must be called with the i_lock held! */
524 : : static inline void
525 : : locks_delete_global_locks(struct file_lock *fl)
526 : : {
527 : : /*
528 : : * Avoid taking lock if already unhashed. This is safe since this check
529 : : * is done while holding the i_lock, and new insertions into the list
530 : : * also require that it be held.
531 : : */
532 [ + + ]: 1068729 : if (hlist_unhashed(&fl->fl_link))
533 : : return;
534 : 1068724 : lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
535 : : hlist_del_init(&fl->fl_link);
536 : 1068687 : lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
537 : : }
538 : :
539 : : static unsigned long
540 : 0 : posix_owner_key(struct file_lock *fl)
541 : : {
542 [ - + ][ # # ]: 390 : if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
[ - + ][ # # ]
543 : 0 : return fl->fl_lmops->lm_owner_key(fl);
544 : 390 : return (unsigned long)fl->fl_owner;
545 : : }
546 : :
547 : : static inline void
548 : : locks_insert_global_blocked(struct file_lock *waiter)
549 : : {
550 : 194 : hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
551 : : }
552 : :
553 : : static inline void
554 : : locks_delete_global_blocked(struct file_lock *waiter)
555 : : {
556 : : hash_del(&waiter->fl_link);
557 : : }
558 : :
559 : : /* Remove waiter from blocker's block list.
560 : : * When blocker ends up pointing to itself then the list is empty.
561 : : *
562 : : * Must be called with blocked_lock_lock held.
563 : : */
564 : : static void __locks_delete_block(struct file_lock *waiter)
565 : : {
566 : : locks_delete_global_blocked(waiter);
567 : 194 : list_del_init(&waiter->fl_block);
568 : 0 : waiter->fl_next = NULL;
569 : : }
570 : :
571 : 0 : static void locks_delete_block(struct file_lock *waiter)
572 : : {
573 : : spin_lock(&blocked_lock_lock);
574 : : __locks_delete_block(waiter);
575 : : spin_unlock(&blocked_lock_lock);
576 : 0 : }
577 : :
578 : : /* Insert waiter into blocker's block list.
579 : : * We use a circular list so that processes can be easily woken up in
580 : : * the order they blocked. The documentation doesn't require this but
581 : : * it seems like the reasonable thing to do.
582 : : *
583 : : * Must be called with both the i_lock and blocked_lock_lock held. The fl_block
584 : : * list itself is protected by the file_lock_list, but by ensuring that the
585 : : * i_lock is also held on insertions we can avoid taking the blocked_lock_lock
586 : : * in some cases when we see that the fl_block list is empty.
587 : : */
588 : 0 : static void __locks_insert_block(struct file_lock *blocker,
589 : : struct file_lock *waiter)
590 : : {
591 [ - + ]: 194 : BUG_ON(!list_empty(&waiter->fl_block));
592 : 194 : waiter->fl_next = blocker;
593 : 194 : list_add_tail(&waiter->fl_block, &blocker->fl_block);
594 [ + - ]: 194 : if (IS_POSIX(blocker))
595 : : locks_insert_global_blocked(waiter);
596 : 194 : }
597 : :
598 : : /* Must be called with i_lock held. */
599 : 0 : static void locks_insert_block(struct file_lock *blocker,
600 : : struct file_lock *waiter)
601 : : {
602 : : spin_lock(&blocked_lock_lock);
603 : 0 : __locks_insert_block(blocker, waiter);
604 : : spin_unlock(&blocked_lock_lock);
605 : 0 : }
606 : :
607 : : /*
608 : : * Wake up processes blocked waiting for blocker.
609 : : *
610 : : * Must be called with the inode->i_lock held!
611 : : */
612 : 0 : static void locks_wake_up_blocks(struct file_lock *blocker)
613 : : {
614 : : /*
615 : : * Avoid taking global lock if list is empty. This is safe since new
616 : : * blocked requests are only added to the list under the i_lock, and
617 : : * the i_lock is always held here. Note that removal from the fl_block
618 : : * list does not require the i_lock, so we must recheck list_empty()
619 : : * after acquiring the blocked_lock_lock.
620 : : */
621 [ + + ]: 1068893 : if (list_empty(&blocker->fl_block))
622 : 1068893 : return;
623 : :
624 : : spin_lock(&blocked_lock_lock);
625 [ + + ]: 388 : while (!list_empty(&blocker->fl_block)) {
626 : : struct file_lock *waiter;
627 : :
628 : 194 : waiter = list_first_entry(&blocker->fl_block,
629 : : struct file_lock, fl_block);
630 : : __locks_delete_block(waiter);
631 [ - ][ # # ]: 194 : if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
632 : 0 : waiter->fl_lmops->lm_notify(waiter);
633 : : else
634 : 0 : wake_up(&waiter->fl_wait);
635 : : }
636 : : spin_unlock(&blocked_lock_lock);
637 : : }
638 : :
639 : : /* Insert file lock fl into an inode's lock list at the position indicated
640 : : * by pos. At the same time add the lock to the global file lock list.
641 : : *
642 : : * Must be called with the i_lock held!
643 : : */
644 : 0 : static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
645 : : {
646 : 2137453 : fl->fl_nspid = get_pid(task_tgid(current));
647 : :
648 : : /* insert into file's list */
649 : 1068724 : fl->fl_next = *pos;
650 : 1068724 : *pos = fl;
651 : :
652 : : locks_insert_global_locks(fl);
653 : 1068729 : }
654 : :
655 : : /*
656 : : * Delete a lock and then free it.
657 : : * Wake up processes that are blocked waiting for this lock,
658 : : * notify the FS that the lock has been cleared and
659 : : * finally free the lock.
660 : : *
661 : : * Must be called with the i_lock held!
662 : : */
663 : 0 : static void locks_delete_lock(struct file_lock **thisfl_p)
664 : : {
665 : 1068729 : struct file_lock *fl = *thisfl_p;
666 : :
667 : : locks_delete_global_locks(fl);
668 : :
669 : 1068719 : *thisfl_p = fl->fl_next;
670 : 1068719 : fl->fl_next = NULL;
671 : :
672 [ + - ]: 1068719 : if (fl->fl_nspid) {
673 : 1068719 : put_pid(fl->fl_nspid);
674 : 1068718 : fl->fl_nspid = NULL;
675 : : }
676 : :
677 : 1068718 : locks_wake_up_blocks(fl);
678 : 1068403 : locks_free_lock(fl);
679 : 1068692 : }
680 : :
681 : : /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
682 : : * checks for shared/exclusive status of overlapping locks.
683 : : */
684 : : static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
685 : : {
686 [ + + ][ # # ]: 40783 : if (sys_fl->fl_type == F_WRLCK)
[ # # ][ # # ]
[ + + ]
687 : : return 1;
688 [ + + ][ # # ]: 5452 : if (caller_fl->fl_type == F_WRLCK)
[ # # ][ # # ]
[ + + ]
689 : : return 1;
690 : : return 0;
691 : : }
692 : :
693 : : /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
694 : : * checking before calling the locks_conflict().
695 : : */
696 : 0 : static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
697 : : {
698 : : /* POSIX locks owned by the same process do not conflict with
699 : : * each other.
700 : : */
701 [ + - ][ + + ]: 34590 : if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl))
702 : : return (0);
703 : :
704 : : /* Check whether they overlap */
705 [ + ]: 34021 : if (!locks_overlap(caller_fl, sys_fl))
706 : : return 0;
707 : :
708 : 6181 : return (locks_conflict(caller_fl, sys_fl));
709 : : }
710 : :
711 : : /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
712 : : * checking before calling the locks_conflict().
713 : : */
714 : 6 : static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
715 : : {
716 : : /* FLOCK locks referring to the same filp do not conflict with
717 : : * each other.
718 : : */
719 [ + - ][ + - ]: 6 : if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
720 : : return (0);
721 [ + - ][ + ]: 6 : if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
722 : : return 0;
723 : :
724 : : return (locks_conflict(caller_fl, sys_fl));
725 : : }
726 : :
727 : : void
728 : 0 : posix_test_lock(struct file *filp, struct file_lock *fl)
729 : : {
730 : : struct file_lock *cfl;
731 : : struct inode *inode = file_inode(filp);
732 : :
733 : : spin_lock(&inode->i_lock);
734 [ + + ]: 11436 : for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
735 [ - + ]: 10576 : if (!IS_POSIX(cfl))
736 : 0 : continue;
737 [ + + ]: 10576 : if (posix_locks_conflict(fl, cfl))
738 : : break;
739 : : }
740 [ + + ]: 644 : if (cfl) {
741 : : __locks_copy_lock(fl, cfl);
742 [ + - ]: 428 : if (cfl->fl_nspid)
743 : 428 : fl->fl_pid = pid_vnr(cfl->fl_nspid);
744 : : } else
745 : 216 : fl->fl_type = F_UNLCK;
746 : : spin_unlock(&inode->i_lock);
747 : 644 : return;
748 : : }
749 : : EXPORT_SYMBOL(posix_test_lock);
750 : :
751 : : /*
752 : : * Deadlock detection:
753 : : *
754 : : * We attempt to detect deadlocks that are due purely to posix file
755 : : * locks.
756 : : *
757 : : * We assume that a task can be waiting for at most one lock at a time.
758 : : * So for any acquired lock, the process holding that lock may be
759 : : * waiting on at most one other lock. That lock in turns may be held by
760 : : * someone waiting for at most one other lock. Given a requested lock
761 : : * caller_fl which is about to wait for a conflicting lock block_fl, we
762 : : * follow this chain of waiters to ensure we are not about to create a
763 : : * cycle.
764 : : *
765 : : * Since we do this before we ever put a process to sleep on a lock, we
766 : : * are ensured that there is never a cycle; that is what guarantees that
767 : : * the while() loop in posix_locks_deadlock() eventually completes.
768 : : *
769 : : * Note: the above assumption may not be true when handling lock
770 : : * requests from a broken NFS client. It may also fail in the presence
771 : : * of tasks (such as posix threads) sharing the same open file table.
772 : : *
773 : : * To handle those cases, we just bail out after a few iterations.
774 : : */
775 : :
776 : : #define MAX_DEADLK_ITERATIONS 10
777 : :
778 : : /* Find a lock that the owner of the given block_fl is blocking on. */
779 : 0 : static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
780 : : {
781 : : struct file_lock *fl;
782 : :
783 [ + + ][ # # ]: 196 : hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
[ + + ]
784 [ + - ]: 2 : if (posix_same_owner(fl, block_fl))
785 : 2 : return fl->fl_next;
786 : : }
787 : : return NULL;
788 : : }
789 : :
790 : : /* Must be called with the blocked_lock_lock held! */
791 : 0 : static int posix_locks_deadlock(struct file_lock *caller_fl,
792 : : struct file_lock *block_fl)
793 : : {
794 : : int i = 0;
795 : :
796 [ + + ]: 196 : while ((block_fl = what_owner_is_waiting_for(block_fl))) {
797 [ + - ]: 2 : if (i++ > MAX_DEADLK_ITERATIONS)
798 : : return 0;
799 [ - + ]: 2 : if (posix_same_owner(caller_fl, block_fl))
800 : : return 1;
801 : : }
802 : : return 0;
803 : : }
804 : :
805 : : /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
806 : : * after any leases, but before any posix locks.
807 : : *
808 : : * Note that if called with an FL_EXISTS argument, the caller may determine
809 : : * whether or not a lock was successfully freed by testing the return
810 : : * value for -ENOENT.
811 : : */
812 : 0 : static int flock_lock_file(struct file *filp, struct file_lock *request)
813 : : {
814 : : struct file_lock *new_fl = NULL;
815 : : struct file_lock **before;
816 : : struct inode * inode = file_inode(filp);
817 : : int error = 0;
818 : : int found = 0;
819 : :
820 [ + - ][ + + ]: 82 : if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
821 : 46 : new_fl = locks_alloc_lock();
822 [ + - ]: 46 : if (!new_fl)
823 : : return -ENOMEM;
824 : : }
825 : :
826 : : spin_lock(&inode->i_lock);
827 [ + - ]: 82 : if (request->fl_flags & FL_ACCESS)
828 : : goto find_conflict;
829 : :
830 [ + + ]: 88 : for_each_lock(inode, before) {
831 : : struct file_lock *fl = *before;
832 [ + - ]: 42 : if (IS_POSIX(fl))
833 : : break;
834 [ - + ]: 42 : if (IS_LEASE(fl))
835 : 0 : continue;
836 [ + + ]: 42 : if (filp != fl->fl_file)
837 : 6 : continue;
838 [ + - ]: 36 : if (request->fl_type == fl->fl_type)
839 : : goto out;
840 : : found = 1;
841 : 36 : locks_delete_lock(before);
842 : 36 : break;
843 : : }
844 : :
845 [ + + ]: 82 : if (request->fl_type == F_UNLCK) {
846 [ - + ][ # # ]: 36 : if ((request->fl_flags & FL_EXISTS) && !found)
847 : : error = -ENOENT;
848 : : goto out;
849 : : }
850 : :
851 : : /*
852 : : * If a higher-priority process was blocked on the old file lock,
853 : : * give it the opportunity to lock the file.
854 : : */
855 [ - + ]: 46 : if (found) {
856 : : spin_unlock(&inode->i_lock);
857 : 0 : cond_resched();
858 : : spin_lock(&inode->i_lock);
859 : : }
860 : :
861 : : find_conflict:
862 [ + + ]: 47 : for_each_lock(inode, before) {
863 : : struct file_lock *fl = *before;
864 [ + - ]: 6 : if (IS_POSIX(fl))
865 : : break;
866 [ - + ]: 6 : if (IS_LEASE(fl))
867 : 0 : continue;
868 [ + + ]: 6 : if (!flock_locks_conflict(request, fl))
869 : 1 : continue;
870 : : error = -EAGAIN;
871 [ - + ]: 5 : if (!(request->fl_flags & FL_SLEEP))
872 : : goto out;
873 : : error = FILE_LOCK_DEFERRED;
874 : 0 : locks_insert_block(fl, request);
875 : 0 : goto out;
876 : : }
877 [ + - ]: 41 : if (request->fl_flags & FL_ACCESS)
878 : : goto out;
879 : 41 : locks_copy_lock(new_fl, request);
880 : 41 : locks_insert_lock(before, new_fl);
881 : : new_fl = NULL;
882 : : error = 0;
883 : :
884 : : out:
885 : : spin_unlock(&inode->i_lock);
886 [ + + ]: 82 : if (new_fl)
887 : 5 : locks_free_lock(new_fl);
888 : 82 : return error;
889 : : }
890 : :
891 : 0 : static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
892 : : {
893 : : struct file_lock *fl;
894 : : struct file_lock *new_fl = NULL;
895 : : struct file_lock *new_fl2 = NULL;
896 : : struct file_lock *left = NULL;
897 : : struct file_lock *right = NULL;
898 : : struct file_lock **before;
899 : : int error;
900 : : bool added = false;
901 : :
902 : : /*
903 : : * We may need two file_lock structures for this operation,
904 : : * so we get them in advance to avoid races.
905 : : *
906 : : * In some cases we can be sure, that no new locks will be needed
907 : : */
908 [ + + ][ + + ]: 2139129 : if (!(request->fl_flags & FL_ACCESS) &&
909 [ + + ]: 1069261 : (request->fl_type != F_UNLCK ||
910 [ + + ]: 1053360 : request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
911 : 1086549 : new_fl = locks_alloc_lock();
912 : 1086549 : new_fl2 = locks_alloc_lock();
913 : : }
914 : :
915 : : spin_lock(&inode->i_lock);
916 : : /*
917 : : * New lock request. Walk all POSIX locks and look for conflicts. If
918 : : * there are any, either return error or put the request on the
919 : : * blocker's list of waiters and the global blocked_hash.
920 : : */
921 [ + + ]: 2139099 : if (request->fl_type != F_UNLCK) {
922 [ + + ]: 1093123 : for_each_lock(inode, before) {
923 : : fl = *before;
924 [ - + ]: 24014 : if (!IS_POSIX(fl))
925 : 0 : continue;
926 [ + + ]: 24014 : if (!posix_locks_conflict(request, fl))
927 : 23367 : continue;
928 [ - + ]: 647 : if (conflock)
929 : : __locks_copy_lock(conflock, fl);
930 : : error = -EAGAIN;
931 [ + + ]: 647 : if (!(request->fl_flags & FL_SLEEP))
932 : : goto out;
933 : : /*
934 : : * Deadlock detection and insertion into the blocked
935 : : * locks list must be done while holding the same lock!
936 : : */
937 : : error = -EDEADLK;
938 : : spin_lock(&blocked_lock_lock);
939 [ + + ]: 196 : if (likely(!posix_locks_deadlock(request, fl))) {
940 : : error = FILE_LOCK_DEFERRED;
941 : 194 : __locks_insert_block(fl, request);
942 : : }
943 : : spin_unlock(&blocked_lock_lock);
944 : : goto out;
945 : : }
946 : : }
947 : :
948 : : /* If we're just looking for a conflict, we're done. */
949 : : error = 0;
950 [ + + ]: 2138452 : if (request->fl_flags & FL_ACCESS)
951 : : goto out;
952 : :
953 : : /*
954 : : * Find the first old lock with the same owner as the new lock.
955 : : */
956 : :
957 : 2138287 : before = &inode->i_flock;
958 : :
959 : : /* First skip locks owned by other processes. */
960 [ + + ]: 3261615 : while ((fl = *before) && (!IS_POSIX(fl) ||
[ + + + + ]
961 : 1096194 : !posix_same_owner(request, fl))) {
962 : 27290 : before = &fl->fl_next;
963 : : }
964 : :
965 : : /* Process locks with this owner. */
966 [ + + ][ + + ]: 3207270 : while ((fl = *before) && posix_same_owner(request, fl)) {
967 : : /* Detect adjacent or overlapping regions (if same lock type)
968 : : */
969 [ + + ]: 1069265 : if (request->fl_type == fl->fl_type) {
970 : : /* In all comparisons of start vs end, use
971 : : * "start - 1" rather than "end + 1". If end
972 : : * is OFFSET_MAX, end + 1 will become negative.
973 : : */
974 [ + + ]: 729 : if (fl->fl_end < request->fl_start - 1)
975 : : goto next_lock;
976 : : /* If the next lock in the list has entirely bigger
977 : : * addresses than the new one, insert the lock here.
978 : : */
979 [ + - ]: 463 : if (fl->fl_start - 1 > request->fl_end)
980 : : break;
981 : :
982 : : /* If we come here, the new and old lock are of the
983 : : * same type and adjacent or overlapping. Make one
984 : : * lock yielding from the lower start address of both
985 : : * locks to the higher end address.
986 : : */
987 [ - + ]: 463 : if (fl->fl_start > request->fl_start)
988 : 0 : fl->fl_start = request->fl_start;
989 : : else
990 : 463 : request->fl_start = fl->fl_start;
991 [ + + ]: 463 : if (fl->fl_end < request->fl_end)
992 : 8 : fl->fl_end = request->fl_end;
993 : : else
994 : 455 : request->fl_end = fl->fl_end;
995 [ - + ]: 463 : if (added) {
996 : 0 : locks_delete_lock(before);
997 : 3 : continue;
998 : : }
999 : : request = fl;
1000 : : added = true;
1001 : : }
1002 : : else {
1003 : : /* Processing for different lock types is a bit
1004 : : * more complex.
1005 : : */
1006 [ + ]: 1068536 : if (fl->fl_end < request->fl_start)
1007 : : goto next_lock;
1008 [ + + ]: 1068770 : if (fl->fl_start > request->fl_end)
1009 : : break;
1010 [ + + ]: 1068746 : if (request->fl_type == F_UNLCK)
1011 : : added = true;
1012 [ + + ]: 1068746 : if (fl->fl_start < request->fl_start)
1013 : : left = fl;
1014 : : /* If the next lock in the list has a higher end
1015 : : * address than the new one, insert the new one here.
1016 : : */
1017 [ + + ]: 1068746 : if (fl->fl_end > request->fl_end) {
1018 : : right = fl;
1019 : : break;
1020 : : }
1021 [ + + ]: 1068691 : if (fl->fl_start >= request->fl_start) {
1022 : : /* The new lock completely replaces an old
1023 : : * one (This may happen several times).
1024 : : */
1025 [ + + ]: 1068672 : if (added) {
1026 : 1068660 : locks_delete_lock(before);
1027 : 1068625 : continue;
1028 : : }
1029 : : /* Replace the old lock with the new one.
1030 : : * Wake up anybody waiting for the old one,
1031 : : * as the change in lock type might satisfy
1032 : : * their needs.
1033 : : */
1034 : 12 : locks_wake_up_blocks(fl);
1035 : 12 : fl->fl_start = request->fl_start;
1036 : 12 : fl->fl_end = request->fl_end;
1037 : 12 : fl->fl_type = request->fl_type;
1038 : : locks_release_private(fl);
1039 : 12 : locks_copy_private(fl, request);
1040 : : request = fl;
1041 : : added = true;
1042 : : }
1043 : : }
1044 : : /* Go on to next lock.
1045 : : */
1046 : : next_lock:
1047 : 1069139 : before = &fl->fl_next;
1048 : : }
1049 : :
1050 : : /*
1051 : : * The above code only modifies existing locks in case of merging or
1052 : : * replacing. If new lock(s) need to be inserted all modifications are
1053 : : * done below this, so it's safe yet to bail out.
1054 : : */
1055 : : error = -ENOLCK; /* "no luck" */
1056 [ + ][ + ]: 2138090 : if (right && left == right && !new_fl2)
1057 : : goto out;
1058 : :
1059 : : error = 0;
1060 [ + + ]: 2138475 : if (!added) {
1061 [ + + ]: 1069437 : if (request->fl_type == F_UNLCK) {
1062 [ - + ]: 813 : if (request->fl_flags & FL_EXISTS)
1063 : : error = -ENOENT;
1064 : : goto out;
1065 : : }
1066 : :
1067 [ + - ]: 1068624 : if (!new_fl) {
1068 : : error = -ENOLCK;
1069 : : goto out;
1070 : : }
1071 : 1068624 : locks_copy_lock(new_fl, request);
1072 : 1068617 : locks_insert_lock(before, new_fl);
1073 : : new_fl = NULL;
1074 : : }
1075 [ + + ]: 2137662 : if (right) {
1076 [ + + ]: 72 : if (left == right) {
1077 : : /* The new lock breaks the old one in two pieces,
1078 : : * so we have to use the second new lock.
1079 : : */
1080 : : left = new_fl2;
1081 : : new_fl2 = NULL;
1082 : 56 : locks_copy_lock(left, right);
1083 : 56 : locks_insert_lock(before, left);
1084 : : }
1085 : 72 : right->fl_start = request->fl_end + 1;
1086 : 72 : locks_wake_up_blocks(right);
1087 : : }
1088 [ + + ]: 2137662 : if (left) {
1089 : 72 : left->fl_end = request->fl_start - 1;
1090 : 72 : locks_wake_up_blocks(left);
1091 : : }
1092 : : out:
1093 : : spin_unlock(&inode->i_lock);
1094 : : /*
1095 : : * Free any unused locks.
1096 : : */
1097 [ + + ]: 2139133 : if (new_fl)
1098 : 17929 : locks_free_lock(new_fl);
1099 [ + + ]: 2139123 : if (new_fl2)
1100 : 1086487 : locks_free_lock(new_fl2);
1101 : 2139085 : return error;
1102 : : }
1103 : :
1104 : : /**
1105 : : * posix_lock_file - Apply a POSIX-style lock to a file
1106 : : * @filp: The file to apply the lock to
1107 : : * @fl: The lock to be applied
1108 : : * @conflock: Place to return a copy of the conflicting lock, if found.
1109 : : *
1110 : : * Add a POSIX style lock to a file.
1111 : : * We merge adjacent & overlapping locks whenever possible.
1112 : : * POSIX locks are sorted by owner task, then by starting address
1113 : : *
1114 : : * Note that if called with an FL_EXISTS argument, the caller may determine
1115 : : * whether or not a lock was successfully freed by testing the return
1116 : : * value for -ENOENT.
1117 : : */
1118 : 0 : int posix_lock_file(struct file *filp, struct file_lock *fl,
1119 : : struct file_lock *conflock)
1120 : : {
1121 : 2139100 : return __posix_lock_file(file_inode(filp), fl, conflock);
1122 : : }
1123 : : EXPORT_SYMBOL(posix_lock_file);
1124 : :
1125 : : /**
1126 : : * posix_lock_file_wait - Apply a POSIX-style lock to a file
1127 : : * @filp: The file to apply the lock to
1128 : : * @fl: The lock to be applied
1129 : : *
1130 : : * Add a POSIX style lock to a file.
1131 : : * We merge adjacent & overlapping locks whenever possible.
1132 : : * POSIX locks are sorted by owner task, then by starting address
1133 : : */
1134 : 0 : int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1135 : : {
1136 : : int error;
1137 : : might_sleep ();
1138 : : for (;;) {
1139 : : error = posix_lock_file(filp, fl, NULL);
1140 [ # # ]: 0 : if (error != FILE_LOCK_DEFERRED)
1141 : : break;
1142 [ # # ][ # # ]: 0 : error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
[ # # ]
1143 [ # # ]: 0 : if (!error)
1144 : 0 : continue;
1145 : :
1146 : 0 : locks_delete_block(fl);
1147 : 0 : break;
1148 : 0 : }
1149 : 0 : return error;
1150 : : }
1151 : : EXPORT_SYMBOL(posix_lock_file_wait);
1152 : :
1153 : : /**
1154 : : * locks_mandatory_locked - Check for an active lock
1155 : : * @inode: the file to check
1156 : : *
1157 : : * Searches the inode's list of locks to find any POSIX locks which conflict.
1158 : : * This function is called from locks_verify_locked() only.
1159 : : */
1160 : 0 : int locks_mandatory_locked(struct inode *inode)
1161 : : {
1162 : 0 : fl_owner_t owner = current->files;
1163 : : struct file_lock *fl;
1164 : :
1165 : : /*
1166 : : * Search the lock list for this inode for any POSIX locks.
1167 : : */
1168 : : spin_lock(&inode->i_lock);
1169 [ # # ]: 0 : for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
1170 [ # # ]: 0 : if (!IS_POSIX(fl))
1171 : 0 : continue;
1172 [ # # ]: 0 : if (fl->fl_owner != owner)
1173 : : break;
1174 : : }
1175 : : spin_unlock(&inode->i_lock);
1176 [ # # ]: 0 : return fl ? -EAGAIN : 0;
1177 : : }
1178 : :
1179 : : /**
1180 : : * locks_mandatory_area - Check for a conflicting lock
1181 : : * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1182 : : * for shared
1183 : : * @inode: the file to check
1184 : : * @filp: how the file was opened (if it was)
1185 : : * @offset: start of area to check
1186 : : * @count: length of area to check
1187 : : *
1188 : : * Searches the inode's list of locks to find any POSIX locks which conflict.
1189 : : * This function is called from rw_verify_area() and
1190 : : * locks_verify_truncate().
1191 : : */
1192 : 0 : int locks_mandatory_area(int read_write, struct inode *inode,
1193 : : struct file *filp, loff_t offset,
1194 : : size_t count)
1195 : : {
1196 : : struct file_lock fl;
1197 : : int error;
1198 : :
1199 : 30 : locks_init_lock(&fl);
1200 : 30 : fl.fl_owner = current->files;
1201 : 30 : fl.fl_pid = current->tgid;
1202 : 30 : fl.fl_file = filp;
1203 : 30 : fl.fl_flags = FL_POSIX | FL_ACCESS;
1204 [ + - ][ - + ]: 30 : if (filp && !(filp->f_flags & O_NONBLOCK))
1205 : 0 : fl.fl_flags |= FL_SLEEP;
1206 : 30 : fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1207 : 30 : fl.fl_start = offset;
1208 : 30 : fl.fl_end = offset + count - 1;
1209 : :
1210 : : for (;;) {
1211 : 30 : error = __posix_lock_file(inode, &fl, NULL);
1212 [ - + ]: 30 : if (error != FILE_LOCK_DEFERRED)
1213 : : break;
1214 [ # # ][ # # ]: 0 : error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
[ # # ]
1215 [ # # ]: 0 : if (!error) {
1216 : : /*
1217 : : * If we've been sleeping someone might have
1218 : : * changed the permissions behind our back.
1219 : : */
1220 [ # # ]: 0 : if (__mandatory_lock(inode))
1221 : 0 : continue;
1222 : : }
1223 : :
1224 : 0 : locks_delete_block(&fl);
1225 : 0 : break;
1226 : 0 : }
1227 : :
1228 : 30 : return error;
1229 : : }
1230 : :
1231 : : EXPORT_SYMBOL(locks_mandatory_area);
1232 : :
1233 : : static void lease_clear_pending(struct file_lock *fl, int arg)
1234 : : {
1235 [ + - - ]: 8 : switch (arg) {
1236 : : case F_UNLCK:
1237 : 8 : fl->fl_flags &= ~FL_UNLOCK_PENDING;
1238 : : /* fall through: */
1239 : : case F_RDLCK:
1240 : 8 : fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1241 : : }
1242 : : }
1243 : :
1244 : : /* We already had a lease on this file; just change its type */
1245 : 0 : int lease_modify(struct file_lock **before, int arg)
1246 : : {
1247 : 8 : struct file_lock *fl = *before;
1248 : : int error = assign_type(fl, arg);
1249 : :
1250 [ + - ]: 8 : if (error)
1251 : : return error;
1252 : : lease_clear_pending(fl, arg);
1253 : 8 : locks_wake_up_blocks(fl);
1254 [ + - ]: 8 : if (arg == F_UNLCK) {
1255 : 8 : struct file *filp = fl->fl_file;
1256 : :
1257 : 8 : f_delown(filp);
1258 : 8 : filp->f_owner.signum = 0;
1259 : 8 : fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1260 [ - + ]: 8 : if (fl->fl_fasync != NULL) {
1261 : 0 : printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1262 : 0 : fl->fl_fasync = NULL;
1263 : : }
1264 : 8 : locks_delete_lock(before);
1265 : : }
1266 : : return 0;
1267 : : }
1268 : :
1269 : : EXPORT_SYMBOL(lease_modify);
1270 : :
1271 : : static bool past_time(unsigned long then)
1272 : : {
1273 [ # # ][ # # ]: 19559 : if (!then)
1274 : : /* 0 is a special value meaning "this never expires": */
1275 : : return false;
1276 [ # # ][ # # ]: 0 : return time_after(jiffies, then);
1277 : : }
1278 : :
1279 : 0 : static void time_out_leases(struct inode *inode)
1280 : : {
1281 : : struct file_lock **before;
1282 : : struct file_lock *fl;
1283 : :
1284 : 19559 : before = &inode->i_flock;
1285 [ + + ][ + + ]: 19559 : while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {
[ - + ]
1286 [ # # ]: 0 : if (past_time(fl->fl_downgrade_time))
1287 : 0 : lease_modify(before, F_RDLCK);
1288 [ # # ]: 0 : if (past_time(fl->fl_break_time))
1289 : 0 : lease_modify(before, F_UNLCK);
1290 [ # # ]: 0 : if (fl == *before) /* lease_modify may have freed fl */
1291 : 0 : before = &fl->fl_next;
1292 : : }
1293 : 19559 : }
1294 : :
1295 : 0 : static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1296 : : {
1297 [ # # ][ # # ]: 0 : if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
[ # # ][ # # ]
[ # # ][ # # ]
1298 : : return false;
1299 : 0 : return locks_conflict(breaker, lease);
1300 : : }
1301 : :
1302 : : /**
1303 : : * __break_lease - revoke all outstanding leases on file
1304 : : * @inode: the inode of the file to return
1305 : : * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1306 : : * break all leases
1307 : : * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1308 : : * only delegations
1309 : : *
1310 : : * break_lease (inlined for speed) has checked there already is at least
1311 : : * some kind of lock (maybe a lease) on this file. Leases are broken on
1312 : : * a call to open() or truncate(). This function can sleep unless you
1313 : : * specified %O_NONBLOCK to your open().
1314 : : */
1315 : 0 : int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1316 : : {
1317 : : int error = 0;
1318 : 0 : struct file_lock *new_fl, *flock;
1319 : : struct file_lock *fl;
1320 : : unsigned long break_time;
1321 : : int i_have_this_lease = 0;
1322 : : bool lease_conflict = false;
1323 : 19531 : int want_write = (mode & O_ACCMODE) != O_RDONLY;
1324 : :
1325 : 19531 : new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1326 [ - + ]: 19530 : if (IS_ERR(new_fl))
1327 : 0 : return PTR_ERR(new_fl);
1328 : 19530 : new_fl->fl_flags = type;
1329 : :
1330 : : spin_lock(&inode->i_lock);
1331 : :
1332 : 19531 : time_out_leases(inode);
1333 : :
1334 : 19531 : flock = inode->i_flock;
1335 [ + - ][ - + ]: 19531 : if ((flock == NULL) || !IS_LEASE(flock))
1336 : : goto out;
1337 : :
1338 [ # # ][ # # ]: 0 : for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
1339 [ # # ]: 0 : if (leases_conflict(fl, new_fl)) {
1340 : : lease_conflict = true;
1341 [ # # ]: 0 : if (fl->fl_owner == current->files)
1342 : : i_have_this_lease = 1;
1343 : : }
1344 : : }
1345 [ # # ]: 0 : if (!lease_conflict)
1346 : : goto out;
1347 : :
1348 : : break_time = 0;
1349 [ # # ]: 0 : if (lease_break_time > 0) {
1350 : 0 : break_time = jiffies + lease_break_time * HZ;
1351 [ # # ]: 0 : if (break_time == 0)
1352 : 0 : break_time++; /* so that 0 means no break time */
1353 : : }
1354 : :
1355 [ # # ][ # # ]: 0 : for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
1356 [ # # ]: 0 : if (!leases_conflict(fl, new_fl))
1357 : 0 : continue;
1358 [ # # ]: 0 : if (want_write) {
1359 [ # # ]: 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
1360 : 0 : continue;
1361 : 0 : fl->fl_flags |= FL_UNLOCK_PENDING;
1362 : 0 : fl->fl_break_time = break_time;
1363 : : } else {
1364 [ # # ]: 0 : if (lease_breaking(flock))
1365 : 0 : continue;
1366 : 0 : fl->fl_flags |= FL_DOWNGRADE_PENDING;
1367 : 0 : fl->fl_downgrade_time = break_time;
1368 : : }
1369 : 0 : fl->fl_lmops->lm_break(fl);
1370 : : }
1371 : :
1372 [ # # ][ # # ]: 0 : if (i_have_this_lease || (mode & O_NONBLOCK)) {
1373 : : error = -EWOULDBLOCK;
1374 : : goto out;
1375 : : }
1376 : :
1377 : : restart:
1378 : 0 : break_time = flock->fl_break_time;
1379 [ # # ]: 0 : if (break_time != 0) {
1380 : 0 : break_time -= jiffies;
1381 [ # # ]: 0 : if (break_time == 0)
1382 : 0 : break_time++;
1383 : : }
1384 : 0 : locks_insert_block(flock, new_fl);
1385 : : spin_unlock(&inode->i_lock);
1386 [ # # ][ # # ]: 0 : error = wait_event_interruptible_timeout(new_fl->fl_wait,
[ # # ][ # # ]
[ # # ]
1387 : : !new_fl->fl_next, break_time);
1388 : : spin_lock(&inode->i_lock);
1389 : 0 : locks_delete_block(new_fl);
1390 [ # # ]: 0 : if (error >= 0) {
1391 [ # # ]: 0 : if (error == 0)
1392 : 0 : time_out_leases(inode);
1393 : : /*
1394 : : * Wait for the next conflicting lease that has not been
1395 : : * broken yet
1396 : : */
1397 [ # # ][ # # ]: 0 : for (flock = inode->i_flock; flock && IS_LEASE(flock);
1398 : 0 : flock = flock->fl_next) {
1399 [ # # ]: 0 : if (leases_conflict(new_fl, flock))
1400 : : goto restart;
1401 : : }
1402 : : error = 0;
1403 : : }
1404 : :
1405 : : out:
1406 : : spin_unlock(&inode->i_lock);
1407 : 19531 : locks_free_lock(new_fl);
1408 : 19531 : return error;
1409 : : }
1410 : :
1411 : : EXPORT_SYMBOL(__break_lease);
1412 : :
1413 : : /**
1414 : : * lease_get_mtime - get the last modified time of an inode
1415 : : * @inode: the inode
1416 : : * @time: pointer to a timespec which will contain the last modified time
1417 : : *
1418 : : * This is to force NFS clients to flush their caches for files with
1419 : : * exclusive leases. The justification is that if someone has an
1420 : : * exclusive lease, then they could be modifying it.
1421 : : */
1422 : 0 : void lease_get_mtime(struct inode *inode, struct timespec *time)
1423 : : {
1424 : 0 : struct file_lock *flock = inode->i_flock;
1425 [ # # ][ # # ]: 0 : if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK))
[ # # ]
1426 : 0 : *time = current_fs_time(inode->i_sb);
1427 : : else
1428 : 0 : *time = inode->i_mtime;
1429 : 0 : }
1430 : :
1431 : : EXPORT_SYMBOL(lease_get_mtime);
1432 : :
1433 : : /**
1434 : : * fcntl_getlease - Enquire what lease is currently active
1435 : : * @filp: the file
1436 : : *
1437 : : * The value returned by this function will be one of
1438 : : * (if no lease break is pending):
1439 : : *
1440 : : * %F_RDLCK to indicate a shared lease is held.
1441 : : *
1442 : : * %F_WRLCK to indicate an exclusive lease is held.
1443 : : *
1444 : : * %F_UNLCK to indicate no lease is held.
1445 : : *
1446 : : * (if a lease break is pending):
1447 : : *
1448 : : * %F_RDLCK to indicate an exclusive lease needs to be
1449 : : * changed to a shared lease (or removed).
1450 : : *
1451 : : * %F_UNLCK to indicate the lease needs to be removed.
1452 : : *
1453 : : * XXX: sfr & willy disagree over whether F_INPROGRESS
1454 : : * should be returned to userspace.
1455 : : */
1456 : 0 : int fcntl_getlease(struct file *filp)
1457 : : {
1458 : : struct file_lock *fl;
1459 : : struct inode *inode = file_inode(filp);
1460 : : int type = F_UNLCK;
1461 : :
1462 : : spin_lock(&inode->i_lock);
1463 : 8 : time_out_leases(file_inode(filp));
1464 [ + - ][ + - ]: 8 : for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);
1465 : 0 : fl = fl->fl_next) {
1466 [ + - ]: 8 : if (fl->fl_file == filp) {
1467 : : type = target_leasetype(fl);
1468 : 8 : break;
1469 : : }
1470 : : }
1471 : : spin_unlock(&inode->i_lock);
1472 : 8 : return type;
1473 : : }
1474 : :
1475 : 0 : static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp)
1476 : : {
1477 : : struct file_lock *fl, **before, **my_before = NULL, *lease;
1478 : 18 : struct dentry *dentry = filp->f_path.dentry;
1479 : 12 : struct inode *inode = dentry->d_inode;
1480 : 12 : bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1481 : : int error;
1482 : :
1483 : : lease = *flp;
1484 : : /*
1485 : : * In the delegation case we need mutual exclusion with
1486 : : * a number of operations that take the i_mutex. We trylock
1487 : : * because delegations are an optional optimization, and if
1488 : : * there's some chance of a conflict--we'd rather not
1489 : : * bother, maybe that's a sign this just isn't a good file to
1490 : : * hand out a delegation on.
1491 : : */
1492 [ - + ][ # # ]: 12 : if (is_deleg && !mutex_trylock(&inode->i_mutex))
1493 : : return -EAGAIN;
1494 : :
1495 [ - + ]: 12 : if (is_deleg && arg == F_WRLCK) {
1496 : : /* Write delegations are not currently supported: */
1497 : 0 : mutex_unlock(&inode->i_mutex);
1498 [ # # ][ # # ]: 0 : WARN_ON_ONCE(1);
1499 : : return -EINVAL;
1500 : : }
1501 : :
1502 : : error = -EAGAIN;
1503 [ + + ][ + ]: 12 : if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1504 : : goto out;
1505 [ + + ]: 20 : if ((arg == F_WRLCK)
1506 [ + - ]: 6 : && ((d_count(dentry) > 1)
1507 [ + - ]: 6 : || (atomic_read(&inode->i_count) > 1)))
1508 : : goto out;
1509 : :
1510 : : /*
1511 : : * At this point, we know that if there is an exclusive
1512 : : * lease on this file, then we hold it on this filp
1513 : : * (otherwise our open of this file would have blocked).
1514 : : * And if we are trying to acquire an exclusive lease,
1515 : : * then the file is not open by anyone (including us)
1516 : : * except for this filp.
1517 : : */
1518 : : error = -EAGAIN;
1519 [ - + ]: 8 : for (before = &inode->i_flock;
1520 [ # # ]: 0 : ((fl = *before) != NULL) && IS_LEASE(fl);
1521 : 0 : before = &fl->fl_next) {
1522 [ # # ]: 0 : if (fl->fl_file == filp) {
1523 : : my_before = before;
1524 : 0 : continue;
1525 : : }
1526 : : /*
1527 : : * No exclusive leases if someone else has a lease on
1528 : : * this file:
1529 : : */
1530 [ # # ]: 0 : if (arg == F_WRLCK)
1531 : : goto out;
1532 : : /*
1533 : : * Modifying our existing lease is OK, but no getting a
1534 : : * new lease if someone else is opening for write:
1535 : : */
1536 [ # # ]: 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
1537 : : goto out;
1538 : : }
1539 : :
1540 [ - + ]: 8 : if (my_before != NULL) {
1541 : 0 : error = lease->fl_lmops->lm_change(my_before, arg);
1542 [ # # ]: 0 : if (!error)
1543 : 0 : *flp = *my_before;
1544 : : goto out;
1545 : : }
1546 : :
1547 : : error = -EINVAL;
1548 [ + - ]: 8 : if (!leases_enable)
1549 : : goto out;
1550 : :
1551 : 8 : locks_insert_lock(before, lease);
1552 : : error = 0;
1553 : : out:
1554 [ - + ]: 12 : if (is_deleg)
1555 : 0 : mutex_unlock(&inode->i_mutex);
1556 : 12 : return error;
1557 : : }
1558 : :
1559 : 0 : static int generic_delete_lease(struct file *filp, struct file_lock **flp)
1560 : : {
1561 : : struct file_lock *fl, **before;
1562 : 8 : struct dentry *dentry = filp->f_path.dentry;
1563 : 8 : struct inode *inode = dentry->d_inode;
1564 : :
1565 [ + - ]: 8 : for (before = &inode->i_flock;
1566 [ + - ]: 8 : ((fl = *before) != NULL) && IS_LEASE(fl);
1567 : 0 : before = &fl->fl_next) {
1568 [ - + ]: 8 : if (fl->fl_file != filp)
1569 : 0 : continue;
1570 : 8 : return (*flp)->fl_lmops->lm_change(before, F_UNLCK);
1571 : : }
1572 : : return -EAGAIN;
1573 : : }
1574 : :
1575 : : /**
1576 : : * generic_setlease - sets a lease on an open file
1577 : : * @filp: file pointer
1578 : : * @arg: type of lease to obtain
1579 : : * @flp: input - file_lock to use, output - file_lock inserted
1580 : : *
1581 : : * The (input) flp->fl_lmops->lm_break function is required
1582 : : * by break_lease().
1583 : : *
1584 : : * Called with inode->i_lock held.
1585 : : */
1586 : 0 : int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
1587 : : {
1588 : 20 : struct dentry *dentry = filp->f_path.dentry;
1589 : 20 : struct inode *inode = dentry->d_inode;
1590 : : int error;
1591 : :
1592 [ - + ][ # # ]: 20 : if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1593 : : return -EACCES;
1594 [ + - ]: 20 : if (!S_ISREG(inode->i_mode))
1595 : : return -EINVAL;
1596 : 20 : error = security_file_lock(filp, arg);
1597 [ + - ]: 20 : if (error)
1598 : : return error;
1599 : :
1600 : 20 : time_out_leases(inode);
1601 : :
1602 [ - + ]: 20 : BUG_ON(!(*flp)->fl_lmops->lm_break);
1603 : :
1604 [ + + - ]: 20 : switch (arg) {
1605 : : case F_UNLCK:
1606 : 8 : return generic_delete_lease(filp, flp);
1607 : : case F_RDLCK:
1608 : : case F_WRLCK:
1609 : 12 : return generic_add_lease(filp, arg, flp);
1610 : : default:
1611 : : return -EINVAL;
1612 : : }
1613 : : }
1614 : : EXPORT_SYMBOL(generic_setlease);
1615 : :
1616 : 0 : static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
1617 : : {
1618 [ - + ]: 20 : if (filp->f_op->setlease)
1619 : 0 : return filp->f_op->setlease(filp, arg, lease);
1620 : : else
1621 : 20 : return generic_setlease(filp, arg, lease);
1622 : : }
1623 : :
1624 : : /**
1625 : : * vfs_setlease - sets a lease on an open file
1626 : : * @filp: file pointer
1627 : : * @arg: type of lease to obtain
1628 : : * @lease: file_lock to use
1629 : : *
1630 : : * Call this to establish a lease on the file.
1631 : : * The (*lease)->fl_lmops->lm_break operation must be set; if not,
1632 : : * break_lease will oops!
1633 : : *
1634 : : * This will call the filesystem's setlease file method, if
1635 : : * defined. Note that there is no getlease method; instead, the
1636 : : * filesystem setlease method should call back to setlease() to
1637 : : * add a lease to the inode's lease list, where fcntl_getlease() can
1638 : : * find it. Since fcntl_getlease() only reports whether the current
1639 : : * task holds a lease, a cluster filesystem need only do this for
1640 : : * leases held by processes on this node.
1641 : : *
1642 : : * There is also no break_lease method; filesystems that
1643 : : * handle their own leases should break leases themselves from the
1644 : : * filesystem's open, create, and (on truncate) setattr methods.
1645 : : *
1646 : : * Warning: the only current setlease methods exist only to disable
1647 : : * leases in certain cases. More vfs changes may be required to
1648 : : * allow a full filesystem lease implementation.
1649 : : */
1650 : :
1651 : 0 : int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
1652 : : {
1653 : : struct inode *inode = file_inode(filp);
1654 : : int error;
1655 : :
1656 : : spin_lock(&inode->i_lock);
1657 : 8 : error = __vfs_setlease(filp, arg, lease);
1658 : : spin_unlock(&inode->i_lock);
1659 : :
1660 : 8 : return error;
1661 : : }
1662 : : EXPORT_SYMBOL_GPL(vfs_setlease);
1663 : :
1664 : 0 : static int do_fcntl_delete_lease(struct file *filp)
1665 : : {
1666 : 8 : struct file_lock fl, *flp = &fl;
1667 : :
1668 : 8 : lease_init(filp, F_UNLCK, flp);
1669 : :
1670 : 8 : return vfs_setlease(filp, F_UNLCK, &flp);
1671 : : }
1672 : :
1673 : 0 : static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
1674 : : {
1675 : : struct file_lock *fl, *ret;
1676 : : struct inode *inode = file_inode(filp);
1677 : : struct fasync_struct *new;
1678 : : int error;
1679 : :
1680 : 12 : fl = lease_alloc(filp, arg);
1681 [ - + ]: 12 : if (IS_ERR(fl))
1682 : 0 : return PTR_ERR(fl);
1683 : :
1684 : 12 : new = fasync_alloc();
1685 [ - + ]: 12 : if (!new) {
1686 : 0 : locks_free_lock(fl);
1687 : 0 : return -ENOMEM;
1688 : : }
1689 : 12 : ret = fl;
1690 : : spin_lock(&inode->i_lock);
1691 : 12 : error = __vfs_setlease(filp, arg, &ret);
1692 [ + + ]: 12 : if (error) {
1693 : : spin_unlock(&inode->i_lock);
1694 : 4 : locks_free_lock(fl);
1695 : 4 : goto out_free_fasync;
1696 : : }
1697 [ - + ]: 8 : if (ret != fl)
1698 : 0 : locks_free_lock(fl);
1699 : :
1700 : : /*
1701 : : * fasync_insert_entry() returns the old entry if any.
1702 : : * If there was no old entry, then it used 'new' and
1703 : : * inserted it into the fasync list. Clear new so that
1704 : : * we don't release it here.
1705 : : */
1706 [ + - ]: 8 : if (!fasync_insert_entry(fd, filp, &ret->fl_fasync, new))
1707 : : new = NULL;
1708 : :
1709 : 8 : error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
1710 : : spin_unlock(&inode->i_lock);
1711 : :
1712 : : out_free_fasync:
1713 [ + + ]: 24 : if (new)
1714 : 4 : fasync_free(new);
1715 : 12 : return error;
1716 : : }
1717 : :
1718 : : /**
1719 : : * fcntl_setlease - sets a lease on an open file
1720 : : * @fd: open file descriptor
1721 : : * @filp: file pointer
1722 : : * @arg: type of lease to obtain
1723 : : *
1724 : : * Call this fcntl to establish a lease on the file.
1725 : : * Note that you also need to call %F_SETSIG to
1726 : : * receive a signal when the lease is broken.
1727 : : */
1728 : 0 : int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1729 : : {
1730 [ + + ]: 20 : if (arg == F_UNLCK)
1731 : 8 : return do_fcntl_delete_lease(filp);
1732 : 12 : return do_fcntl_add_lease(fd, filp, arg);
1733 : : }
1734 : :
1735 : : /**
1736 : : * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1737 : : * @filp: The file to apply the lock to
1738 : : * @fl: The lock to be applied
1739 : : *
1740 : : * Add a FLOCK style lock to a file.
1741 : : */
1742 : 82 : int flock_lock_file_wait(struct file *filp, struct file_lock *fl)
1743 : : {
1744 : : int error;
1745 : : might_sleep();
1746 : : for (;;) {
1747 : 82 : error = flock_lock_file(filp, fl);
1748 [ + - ]: 82 : if (error != FILE_LOCK_DEFERRED)
1749 : : break;
1750 [ # # ][ # # ]: 82 : error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
[ # # ]
1751 [ # # ]: 0 : if (!error)
1752 : 0 : continue;
1753 : :
1754 : 0 : locks_delete_block(fl);
1755 : 0 : break;
1756 : 0 : }
1757 : 0 : return error;
1758 : : }
1759 : :
1760 : : EXPORT_SYMBOL(flock_lock_file_wait);
1761 : :
1762 : : /**
1763 : : * sys_flock: - flock() system call.
1764 : : * @fd: the file descriptor to lock.
1765 : : * @cmd: the type of lock to apply.
1766 : : *
1767 : : * Apply a %FL_FLOCK style lock to an open file descriptor.
1768 : : * The @cmd can be one of
1769 : : *
1770 : : * %LOCK_SH -- a shared lock.
1771 : : *
1772 : : * %LOCK_EX -- an exclusive lock.
1773 : : *
1774 : : * %LOCK_UN -- remove an existing lock.
1775 : : *
1776 : : * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1777 : : *
1778 : : * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1779 : : * processes read and write access respectively.
1780 : : */
1781 : 0 : SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
1782 : : {
1783 : : struct fd f = fdget(fd);
1784 : : struct file_lock *lock;
1785 : : int can_sleep, unlock;
1786 : : int error;
1787 : :
1788 : : error = -EBADF;
1789 [ + + ]: 85 : if (!f.file)
1790 : : goto out;
1791 : :
1792 : 84 : can_sleep = !(cmd & LOCK_NB);
1793 : 84 : cmd &= ~LOCK_NB;
1794 : : unlock = (cmd == LOCK_UN);
1795 : :
1796 [ + + ][ + - ]: 84 : if (!unlock && !(cmd & LOCK_MAND) &&
[ + - ]
1797 : 48 : !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
1798 : : goto out_putf;
1799 : :
1800 : 84 : error = flock_make_lock(f.file, &lock, cmd);
1801 [ + + ]: 84 : if (error)
1802 : : goto out_putf;
1803 [ + + ]: 82 : if (can_sleep)
1804 : 40 : lock->fl_flags |= FL_SLEEP;
1805 : :
1806 : 82 : error = security_file_lock(f.file, lock->fl_type);
1807 [ + - ]: 82 : if (error)
1808 : : goto out_free;
1809 : :
1810 [ - + ]: 82 : if (f.file->f_op->flock)
1811 [ # # ]: 0 : error = f.file->f_op->flock(f.file,
1812 : : (can_sleep) ? F_SETLKW : F_SETLK,
1813 : : lock);
1814 : : else
1815 : 82 : error = flock_lock_file_wait(f.file, lock);
1816 : :
1817 : : out_free:
1818 : 82 : locks_free_lock(lock);
1819 : :
1820 : : out_putf:
1821 : : fdput(f);
1822 : : out:
1823 : : return error;
1824 : : }
1825 : :
1826 : : /**
1827 : : * vfs_test_lock - test file byte range lock
1828 : : * @filp: The file to test lock for
1829 : : * @fl: The lock to test; also used to hold result
1830 : : *
1831 : : * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1832 : : * setting conf->fl_type to something other than F_UNLCK.
1833 : : */
1834 : 0 : int vfs_test_lock(struct file *filp, struct file_lock *fl)
1835 : : {
1836 [ - + ]: 644 : if (filp->f_op->lock)
1837 : 0 : return filp->f_op->lock(filp, F_GETLK, fl);
1838 : 644 : posix_test_lock(filp, fl);
1839 : 644 : return 0;
1840 : : }
1841 : : EXPORT_SYMBOL_GPL(vfs_test_lock);
1842 : :
1843 : 0 : static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
1844 : : {
1845 : 314 : flock->l_pid = fl->fl_pid;
1846 : : #if BITS_PER_LONG == 32
1847 : : /*
1848 : : * Make sure we can represent the posix lock via
1849 : : * legacy 32bit flock.
1850 : : */
1851 [ + - ]: 314 : if (fl->fl_start > OFFT_OFFSET_MAX)
1852 : : return -EOVERFLOW;
1853 [ + ]: 314 : if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
1854 : : return -EOVERFLOW;
1855 : : #endif
1856 : 314 : flock->l_start = fl->fl_start;
1857 [ + + ]: 628 : flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1858 : 287 : fl->fl_end - fl->fl_start + 1;
1859 : 314 : flock->l_whence = 0;
1860 : 314 : flock->l_type = fl->fl_type;
1861 : 314 : return 0;
1862 : : }
1863 : :
1864 : : #if BITS_PER_LONG == 32
1865 : : static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
1866 : : {
1867 : 114 : flock->l_pid = fl->fl_pid;
1868 : 114 : flock->l_start = fl->fl_start;
1869 [ + + ]: 114 : flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1870 : 87 : fl->fl_end - fl->fl_start + 1;
1871 : 114 : flock->l_whence = 0;
1872 : : flock->l_type = fl->fl_type;
1873 : : }
1874 : : #endif
1875 : :
1876 : : /* Report the first existing lock that would conflict with l.
1877 : : * This implements the F_GETLK command of fcntl().
1878 : : */
1879 : 0 : int fcntl_getlk(struct file *filp, struct flock __user *l)
1880 : : {
1881 : : struct file_lock file_lock;
1882 : : struct flock flock;
1883 : : int error;
1884 : :
1885 : : error = -EFAULT;
1886 [ + + ]: 425 : if (copy_from_user(&flock, l, sizeof(flock)))
1887 : : goto out;
1888 : : error = -EINVAL;
1889 [ + - ]: 423 : if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
1890 : : goto out;
1891 : :
1892 : 423 : error = flock_to_posix_lock(filp, &file_lock, &flock);
1893 [ + - ]: 423 : if (error)
1894 : : goto out;
1895 : :
1896 : 423 : error = vfs_test_lock(filp, &file_lock);
1897 [ + - ]: 423 : if (error)
1898 : : goto out;
1899 : :
1900 : 423 : flock.l_type = file_lock.fl_type;
1901 [ + + ]: 423 : if (file_lock.fl_type != F_UNLCK) {
1902 : 314 : error = posix_lock_to_flock(&flock, &file_lock);
1903 [ + ]: 314 : if (error)
1904 : : goto out;
1905 : : }
1906 : : error = -EFAULT;
1907 [ + - ]: 423 : if (!copy_to_user(l, &flock, sizeof(flock)))
1908 : : error = 0;
1909 : : out:
1910 : 0 : return error;
1911 : : }
1912 : :
1913 : : /**
1914 : : * vfs_lock_file - file byte range lock
1915 : : * @filp: The file to apply the lock to
1916 : : * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
1917 : : * @fl: The lock to be applied
1918 : : * @conf: Place to return a copy of the conflicting lock, if found.
1919 : : *
1920 : : * A caller that doesn't care about the conflicting lock may pass NULL
1921 : : * as the final argument.
1922 : : *
1923 : : * If the filesystem defines a private ->lock() method, then @conf will
1924 : : * be left unchanged; so a caller that cares should initialize it to
1925 : : * some acceptable default.
1926 : : *
1927 : : * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
1928 : : * locks, the ->lock() interface may return asynchronously, before the lock has
1929 : : * been granted or denied by the underlying filesystem, if (and only if)
1930 : : * lm_grant is set. Callers expecting ->lock() to return asynchronously
1931 : : * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
1932 : : * the request is for a blocking lock. When ->lock() does return asynchronously,
1933 : : * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
1934 : : * request completes.
1935 : : * If the request is for non-blocking lock the file system should return
1936 : : * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
1937 : : * with the result. If the request timed out the callback routine will return a
1938 : : * nonzero return code and the file system should release the lock. The file
1939 : : * system is also responsible to keep a corresponding posix lock when it
1940 : : * grants a lock so the VFS can find out which locks are locally held and do
1941 : : * the correct lock cleanup when required.
1942 : : * The underlying filesystem must not drop the kernel lock or call
1943 : : * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
1944 : : * return code.
1945 : : */
1946 : 0 : int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
1947 : : {
1948 [ - + ]: 2139100 : if (filp->f_op->lock)
1949 : 0 : return filp->f_op->lock(filp, cmd, fl);
1950 : : else
1951 : 2139059 : return posix_lock_file(filp, fl, conf);
1952 : : }
1953 : : EXPORT_SYMBOL_GPL(vfs_lock_file);
1954 : :
1955 : 0 : static int do_lock_file_wait(struct file *filp, unsigned int cmd,
1956 : : struct file_lock *fl)
1957 : : {
1958 : : int error;
1959 : :
1960 : 2131703 : error = security_file_lock(filp, fl->fl_type);
1961 [ + ]: 2131690 : if (error)
1962 : : return error;
1963 : :
1964 : : for (;;) {
1965 : 2131891 : error = vfs_lock_file(filp, cmd, fl, NULL);
1966 [ + + ]: 4263604 : if (error != FILE_LOCK_DEFERRED)
1967 : : break;
1968 [ + - ][ + + ]: 2132091 : error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
[ + - ]
1969 [ + - ]: 194 : if (!error)
1970 : 194 : continue;
1971 : :
1972 : 0 : locks_delete_block(fl);
1973 : 0 : break;
1974 : 194 : }
1975 : :
1976 : 2131707 : return error;
1977 : : }
1978 : :
1979 : : /* Apply the lock described by l to an open file descriptor.
1980 : : * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1981 : : */
1982 : 0 : int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
1983 : : struct flock __user *l)
1984 : : {
1985 : 2125488 : struct file_lock *file_lock = locks_alloc_lock();
1986 : : struct flock flock;
1987 : : struct inode *inode;
1988 : : struct file *f;
1989 : : int error;
1990 : :
1991 [ + ]: 2125246 : if (file_lock == NULL)
1992 : : return -ENOLCK;
1993 : :
1994 : : /*
1995 : : * This might block, so we do it before checking the inode.
1996 : : */
1997 : : error = -EFAULT;
1998 [ + + ]: 2125494 : if (copy_from_user(&flock, l, sizeof(flock)))
1999 : : goto out;
2000 : :
2001 : : inode = file_inode(filp);
2002 : :
2003 : : /* Don't allow mandatory locks on files that may be memory mapped
2004 : : * and shared.
2005 : : */
2006 [ + + ][ + ]: 2125492 : if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2007 : : error = -EAGAIN;
2008 : : goto out;
2009 : : }
2010 : :
2011 : : again:
2012 : 2125439 : error = flock_to_posix_lock(filp, file_lock, &flock);
2013 [ + - ]: 2124767 : if (error)
2014 : : goto out;
2015 [ + + ]: 2124767 : if (cmd == F_SETLKW) {
2016 : 2123664 : file_lock->fl_flags |= FL_SLEEP;
2017 : : }
2018 : :
2019 : : error = -EBADF;
2020 [ + + + ]: 2124767 : switch (flock.l_type) {
2021 : : case F_RDLCK:
2022 [ + - ]: 312469 : if (!(filp->f_mode & FMODE_READ))
2023 : : goto out;
2024 : : break;
2025 : : case F_WRLCK:
2026 [ + - ]: 750953 : if (!(filp->f_mode & FMODE_WRITE))
2027 : : goto out;
2028 : : break;
2029 : : case F_UNLCK:
2030 : : break;
2031 : : default:
2032 : : error = -EINVAL;
2033 : : goto out;
2034 : : }
2035 : :
2036 : 2125069 : error = do_lock_file_wait(filp, cmd, file_lock);
2037 : :
2038 : : /*
2039 : : * Attempt to detect a close/fcntl race and recover by
2040 : : * releasing the lock that was just acquired.
2041 : : */
2042 : : /*
2043 : : * we need that spin_lock here - it prevents reordering between
2044 : : * update of inode->i_flock and check for it done in close().
2045 : : * rcu_read_lock() wouldn't do.
2046 : : */
2047 : 2125462 : spin_lock(¤t->files->file_lock);
2048 : 2125476 : f = fcheck(fd);
2049 : : spin_unlock(¤t->files->file_lock);
2050 [ - + ][ # # ]: 2125480 : if (!error && f != filp && flock.l_type != F_UNLCK) {
2051 : 0 : flock.l_type = F_UNLCK;
2052 : 0 : goto again;
2053 : : }
2054 : :
2055 : : out:
2056 : 2125233 : locks_free_lock(file_lock);
2057 : 2125485 : return error;
2058 : : }
2059 : :
2060 : : #if BITS_PER_LONG == 32
2061 : : /* Report the first existing lock that would conflict with l.
2062 : : * This implements the F_GETLK command of fcntl().
2063 : : */
2064 : 0 : int fcntl_getlk64(struct file *filp, struct flock64 __user *l)
2065 : : {
2066 : : struct file_lock file_lock;
2067 : : struct flock64 flock;
2068 : : int error;
2069 : :
2070 : : error = -EFAULT;
2071 [ + + ]: 225 : if (copy_from_user(&flock, l, sizeof(flock)))
2072 : : goto out;
2073 : : error = -EINVAL;
2074 [ + - ]: 221 : if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2075 : : goto out;
2076 : :
2077 : 221 : error = flock64_to_posix_lock(filp, &file_lock, &flock);
2078 [ + - ]: 221 : if (error)
2079 : : goto out;
2080 : :
2081 : 221 : error = vfs_test_lock(filp, &file_lock);
2082 [ + - ]: 221 : if (error)
2083 : : goto out;
2084 : :
2085 : 221 : flock.l_type = file_lock.fl_type;
2086 [ + + ]: 221 : if (file_lock.fl_type != F_UNLCK)
2087 : : posix_lock_to_flock64(&flock, &file_lock);
2088 : :
2089 : : error = -EFAULT;
2090 [ + - ]: 221 : if (!copy_to_user(l, &flock, sizeof(flock)))
2091 : : error = 0;
2092 : :
2093 : : out:
2094 : 225 : return error;
2095 : : }
2096 : :
2097 : : /* Apply the lock described by l to an open file descriptor.
2098 : : * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2099 : : */
2100 : 0 : int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2101 : : struct flock64 __user *l)
2102 : : {
2103 : 6222 : struct file_lock *file_lock = locks_alloc_lock();
2104 : : struct flock64 flock;
2105 : : struct inode *inode;
2106 : : struct file *f;
2107 : : int error;
2108 : :
2109 [ + - ]: 6222 : if (file_lock == NULL)
2110 : : return -ENOLCK;
2111 : :
2112 : : /*
2113 : : * This might block, so we do it before checking the inode.
2114 : : */
2115 : : error = -EFAULT;
2116 [ + + ]: 6222 : if (copy_from_user(&flock, l, sizeof(flock)))
2117 : : goto out;
2118 : :
2119 : : inode = file_inode(filp);
2120 : :
2121 : : /* Don't allow mandatory locks on files that may be memory mapped
2122 : : * and shared.
2123 : : */
2124 [ + + ][ + - ]: 6220 : if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2125 : : error = -EAGAIN;
2126 : : goto out;
2127 : : }
2128 : :
2129 : : again:
2130 : 6220 : error = flock64_to_posix_lock(filp, file_lock, &flock);
2131 [ + + ]: 6220 : if (error)
2132 : : goto out;
2133 [ + + ]: 6218 : if (cmd == F_SETLKW64) {
2134 : 2676 : file_lock->fl_flags |= FL_SLEEP;
2135 : : }
2136 : :
2137 : : error = -EBADF;
2138 [ + + + - ]: 6218 : switch (flock.l_type) {
2139 : : case F_RDLCK:
2140 [ + - ]: 2678 : if (!(filp->f_mode & FMODE_READ))
2141 : : goto out;
2142 : : break;
2143 : : case F_WRLCK:
2144 [ + - ]: 3431 : if (!(filp->f_mode & FMODE_WRITE))
2145 : : goto out;
2146 : : break;
2147 : : case F_UNLCK:
2148 : : break;
2149 : : default:
2150 : : error = -EINVAL;
2151 : : goto out;
2152 : : }
2153 : :
2154 : 6218 : error = do_lock_file_wait(filp, cmd, file_lock);
2155 : :
2156 : : /*
2157 : : * Attempt to detect a close/fcntl race and recover by
2158 : : * releasing the lock that was just acquired.
2159 : : */
2160 : 6218 : spin_lock(¤t->files->file_lock);
2161 : 6218 : f = fcheck(fd);
2162 : : spin_unlock(¤t->files->file_lock);
2163 [ - + ][ # # ]: 6218 : if (!error && f != filp && flock.l_type != F_UNLCK) {
2164 : 0 : flock.l_type = F_UNLCK;
2165 : 0 : goto again;
2166 : : }
2167 : :
2168 : : out:
2169 : 6222 : locks_free_lock(file_lock);
2170 : 6222 : return error;
2171 : : }
2172 : : #endif /* BITS_PER_LONG == 32 */
2173 : :
2174 : : /*
2175 : : * This function is called when the file is being removed
2176 : : * from the task's fd array. POSIX locks belonging to this task
2177 : : * are deleted at this time.
2178 : : */
2179 : 0 : void locks_remove_posix(struct file *filp, fl_owner_t owner)
2180 : : {
2181 : : struct file_lock lock;
2182 : :
2183 : : /*
2184 : : * If there are no locks held on this file, we don't need to call
2185 : : * posix_lock_file(). Another process could be setting a lock on this
2186 : : * file at the same time, but we wouldn't remove that lock anyway.
2187 : : */
2188 [ + + ]: 9566433 : if (!file_inode(filp)->i_flock)
2189 : 9559235 : return;
2190 : :
2191 : 7198 : lock.fl_type = F_UNLCK;
2192 : 7198 : lock.fl_flags = FL_POSIX | FL_CLOSE;
2193 : 7198 : lock.fl_start = 0;
2194 : 7198 : lock.fl_end = OFFSET_MAX;
2195 : 7198 : lock.fl_owner = owner;
2196 : 7198 : lock.fl_pid = current->tgid;
2197 : 7198 : lock.fl_file = filp;
2198 : 7198 : lock.fl_ops = NULL;
2199 : 7198 : lock.fl_lmops = NULL;
2200 : :
2201 : 7198 : vfs_lock_file(filp, F_SETLK, &lock, NULL);
2202 : :
2203 [ - + ][ # # ]: 7198 : if (lock.fl_ops && lock.fl_ops->fl_release_private)
2204 : 7198 : lock.fl_ops->fl_release_private(&lock);
2205 : : }
2206 : :
2207 : : EXPORT_SYMBOL(locks_remove_posix);
2208 : :
2209 : : /*
2210 : : * This function is called on the last close of an open file.
2211 : : */
2212 : 0 : void locks_remove_flock(struct file *filp)
2213 : : {
2214 : : struct inode * inode = file_inode(filp);
2215 : : struct file_lock *fl;
2216 : : struct file_lock **before;
2217 : :
2218 [ + + ]: 3872914 : if (!inode->i_flock)
2219 : 3872914 : return;
2220 : :
2221 [ - + ]: 1051 : if (filp->f_op->flock) {
2222 : 0 : struct file_lock fl = {
2223 : 0 : .fl_pid = current->tgid,
2224 : : .fl_file = filp,
2225 : : .fl_flags = FL_FLOCK,
2226 : : .fl_type = F_UNLCK,
2227 : : .fl_end = OFFSET_MAX,
2228 : : };
2229 : 0 : filp->f_op->flock(filp, F_SETLKW, &fl);
2230 [ # # ][ # # ]: 0 : if (fl.fl_ops && fl.fl_ops->fl_release_private)
2231 : 0 : fl.fl_ops->fl_release_private(&fl);
2232 : : }
2233 : :
2234 : : spin_lock(&inode->i_lock);
2235 : 1051 : before = &inode->i_flock;
2236 : :
2237 [ + + ]: 16753 : while ((fl = *before) != NULL) {
2238 [ + + ]: 15702 : if (fl->fl_file == filp) {
2239 [ + - ]: 5 : if (IS_FLOCK(fl)) {
2240 : 5 : locks_delete_lock(before);
2241 : 5 : continue;
2242 : : }
2243 [ # # ]: 0 : if (IS_LEASE(fl)) {
2244 : 0 : lease_modify(before, F_UNLCK);
2245 : 0 : continue;
2246 : : }
2247 : : /* What? */
2248 : 0 : BUG();
2249 : : }
2250 : 15702 : before = &fl->fl_next;
2251 : : }
2252 : : spin_unlock(&inode->i_lock);
2253 : : }
2254 : :
2255 : : /**
2256 : : * posix_unblock_lock - stop waiting for a file lock
2257 : : * @waiter: the lock which was waiting
2258 : : *
2259 : : * lockd needs to block waiting for locks.
2260 : : */
2261 : : int
2262 : 0 : posix_unblock_lock(struct file_lock *waiter)
2263 : : {
2264 : : int status = 0;
2265 : :
2266 : : spin_lock(&blocked_lock_lock);
2267 [ # # ]: 0 : if (waiter->fl_next)
2268 : : __locks_delete_block(waiter);
2269 : : else
2270 : : status = -ENOENT;
2271 : : spin_unlock(&blocked_lock_lock);
2272 : 0 : return status;
2273 : : }
2274 : : EXPORT_SYMBOL(posix_unblock_lock);
2275 : :
2276 : : /**
2277 : : * vfs_cancel_lock - file byte range unblock lock
2278 : : * @filp: The file to apply the unblock to
2279 : : * @fl: The lock to be unblocked
2280 : : *
2281 : : * Used by lock managers to cancel blocked requests
2282 : : */
2283 : 0 : int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2284 : : {
2285 [ # # ]: 0 : if (filp->f_op->lock)
2286 : 0 : return filp->f_op->lock(filp, F_CANCELLK, fl);
2287 : : return 0;
2288 : : }
2289 : :
2290 : : EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2291 : :
2292 : : #ifdef CONFIG_PROC_FS
2293 : : #include <linux/proc_fs.h>
2294 : : #include <linux/seq_file.h>
2295 : :
2296 : : struct locks_iterator {
2297 : : int li_cpu;
2298 : : loff_t li_pos;
2299 : : };
2300 : :
2301 : 0 : static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2302 : : loff_t id, char *pfx)
2303 : : {
2304 : : struct inode *inode = NULL;
2305 : : unsigned int fl_pid;
2306 : :
2307 [ + - ]: 5 : if (fl->fl_nspid)
2308 : 5 : fl_pid = pid_vnr(fl->fl_nspid);
2309 : : else
2310 : 0 : fl_pid = fl->fl_pid;
2311 : :
2312 [ + - ]: 5 : if (fl->fl_file != NULL)
2313 : : inode = file_inode(fl->fl_file);
2314 : :
2315 : 5 : seq_printf(f, "%lld:%s ", id, pfx);
2316 [ - + ]: 5 : if (IS_POSIX(fl)) {
2317 [ # # ][ # # ]: 0 : seq_printf(f, "%6s %s ",
2318 : 0 : (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
2319 : : (inode == NULL) ? "*NOINODE*" :
2320 [ # # ]: 0 : mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2321 [ + - ]: 5 : } else if (IS_FLOCK(fl)) {
2322 [ - + ]: 5 : if (fl->fl_type & LOCK_MAND) {
2323 : 0 : seq_printf(f, "FLOCK MSNFS ");
2324 : : } else {
2325 : 5 : seq_printf(f, "FLOCK ADVISORY ");
2326 : : }
2327 [ # # ]: 0 : } else if (IS_LEASE(fl)) {
2328 : 0 : seq_printf(f, "LEASE ");
2329 [ # # ]: 0 : if (lease_breaking(fl))
2330 : 0 : seq_printf(f, "BREAKING ");
2331 [ # # ]: 0 : else if (fl->fl_file)
2332 : 0 : seq_printf(f, "ACTIVE ");
2333 : : else
2334 : 0 : seq_printf(f, "BREAKER ");
2335 : : } else {
2336 : 0 : seq_printf(f, "UNKNOWN UNKNOWN ");
2337 : : }
2338 [ - + ]: 10 : if (fl->fl_type & LOCK_MAND) {
2339 [ # # ]: 0 : seq_printf(f, "%s ",
2340 : 0 : (fl->fl_type & LOCK_READ)
2341 [ # # ]: 0 : ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2342 [ # # ]: 0 : : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2343 : : } else {
2344 [ - + ]: 10 : seq_printf(f, "%s ",
2345 : : (lease_breaking(fl))
2346 [ # # ]: 0 : ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2347 [ - + ]: 5 : : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
2348 : : }
2349 [ + - ]: 5 : if (inode) {
2350 : : #ifdef WE_CAN_BREAK_LSLK_NOW
2351 : : seq_printf(f, "%d %s:%ld ", fl_pid,
2352 : : inode->i_sb->s_id, inode->i_ino);
2353 : : #else
2354 : : /* userspace relies on this representation of dev_t ;-( */
2355 : 5 : seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
2356 : 5 : MAJOR(inode->i_sb->s_dev),
2357 : : MINOR(inode->i_sb->s_dev), inode->i_ino);
2358 : : #endif
2359 : : } else {
2360 : 0 : seq_printf(f, "%d <none>:0 ", fl_pid);
2361 : : }
2362 [ - + ]: 5 : if (IS_POSIX(fl)) {
2363 [ # # ]: 0 : if (fl->fl_end == OFFSET_MAX)
2364 : 0 : seq_printf(f, "%Ld EOF\n", fl->fl_start);
2365 : : else
2366 : 0 : seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2367 : : } else {
2368 : 5 : seq_printf(f, "0 EOF\n");
2369 : : }
2370 : 5 : }
2371 : :
2372 : 0 : static int locks_show(struct seq_file *f, void *v)
2373 : : {
2374 : 5 : struct locks_iterator *iter = f->private;
2375 : : struct file_lock *fl, *bfl;
2376 : :
2377 : 5 : fl = hlist_entry(v, struct file_lock, fl_link);
2378 : :
2379 : 5 : lock_get_status(f, fl, iter->li_pos, "");
2380 : :
2381 [ - + ]: 10 : list_for_each_entry(bfl, &fl->fl_block, fl_block)
2382 : 0 : lock_get_status(f, bfl, iter->li_pos, " ->");
2383 : :
2384 : 5 : return 0;
2385 : : }
2386 : :
2387 : 0 : static void *locks_start(struct seq_file *f, loff_t *pos)
2388 : : {
2389 : 10 : struct locks_iterator *iter = f->private;
2390 : :
2391 : 10 : iter->li_pos = *pos + 1;
2392 : 10 : lg_global_lock(&file_lock_lglock);
2393 : : spin_lock(&blocked_lock_lock);
2394 : 10 : return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
2395 : : }
2396 : :
2397 : 0 : static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2398 : : {
2399 : 5 : struct locks_iterator *iter = f->private;
2400 : :
2401 : 5 : ++iter->li_pos;
2402 : 5 : return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
2403 : : }
2404 : :
2405 : 0 : static void locks_stop(struct seq_file *f, void *v)
2406 : : {
2407 : : spin_unlock(&blocked_lock_lock);
2408 : 10 : lg_global_unlock(&file_lock_lglock);
2409 : 10 : }
2410 : :
2411 : : static const struct seq_operations locks_seq_operations = {
2412 : : .start = locks_start,
2413 : : .next = locks_next,
2414 : : .stop = locks_stop,
2415 : : .show = locks_show,
2416 : : };
2417 : :
2418 : 0 : static int locks_open(struct inode *inode, struct file *filp)
2419 : : {
2420 : 5 : return seq_open_private(filp, &locks_seq_operations,
2421 : : sizeof(struct locks_iterator));
2422 : : }
2423 : :
2424 : : static const struct file_operations proc_locks_operations = {
2425 : : .open = locks_open,
2426 : : .read = seq_read,
2427 : : .llseek = seq_lseek,
2428 : : .release = seq_release_private,
2429 : : };
2430 : :
2431 : 0 : static int __init proc_locks_init(void)
2432 : : {
2433 : : proc_create("locks", 0, NULL, &proc_locks_operations);
2434 : 0 : return 0;
2435 : : }
2436 : : module_init(proc_locks_init);
2437 : : #endif
2438 : :
2439 : : /**
2440 : : * lock_may_read - checks that the region is free of locks
2441 : : * @inode: the inode that is being read
2442 : : * @start: the first byte to read
2443 : : * @len: the number of bytes to read
2444 : : *
2445 : : * Emulates Windows locking requirements. Whole-file
2446 : : * mandatory locks (share modes) can prohibit a read and
2447 : : * byte-range POSIX locks can prohibit a read if they overlap.
2448 : : *
2449 : : * N.B. this function is only ever called
2450 : : * from knfsd and ownership of locks is never checked.
2451 : : */
2452 : 0 : int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
2453 : : {
2454 : : struct file_lock *fl;
2455 : : int result = 1;
2456 : :
2457 : : spin_lock(&inode->i_lock);
2458 [ # # ]: 0 : for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
2459 [ # # ]: 0 : if (IS_POSIX(fl)) {
2460 [ # # ]: 0 : if (fl->fl_type == F_RDLCK)
2461 : 0 : continue;
2462 [ # # ][ # # ]: 0 : if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
2463 : 0 : continue;
2464 [ # # ]: 0 : } else if (IS_FLOCK(fl)) {
2465 [ # # ]: 0 : if (!(fl->fl_type & LOCK_MAND))
2466 : 0 : continue;
2467 [ # # ]: 0 : if (fl->fl_type & LOCK_READ)
2468 : 0 : continue;
2469 : : } else
2470 : 0 : continue;
2471 : : result = 0;
2472 : : break;
2473 : : }
2474 : : spin_unlock(&inode->i_lock);
2475 : 0 : return result;
2476 : : }
2477 : :
2478 : : EXPORT_SYMBOL(lock_may_read);
2479 : :
2480 : : /**
2481 : : * lock_may_write - checks that the region is free of locks
2482 : : * @inode: the inode that is being written
2483 : : * @start: the first byte to write
2484 : : * @len: the number of bytes to write
2485 : : *
2486 : : * Emulates Windows locking requirements. Whole-file
2487 : : * mandatory locks (share modes) can prohibit a write and
2488 : : * byte-range POSIX locks can prohibit a write if they overlap.
2489 : : *
2490 : : * N.B. this function is only ever called
2491 : : * from knfsd and ownership of locks is never checked.
2492 : : */
2493 : 0 : int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
2494 : : {
2495 : : struct file_lock *fl;
2496 : : int result = 1;
2497 : :
2498 : : spin_lock(&inode->i_lock);
2499 [ # # ]: 0 : for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
2500 [ # # ]: 0 : if (IS_POSIX(fl)) {
2501 [ # # ][ # # ]: 0 : if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
2502 : 0 : continue;
2503 [ # # ]: 0 : } else if (IS_FLOCK(fl)) {
2504 [ # # ]: 0 : if (!(fl->fl_type & LOCK_MAND))
2505 : 0 : continue;
2506 [ # # ]: 0 : if (fl->fl_type & LOCK_WRITE)
2507 : 0 : continue;
2508 : : } else
2509 : 0 : continue;
2510 : : result = 0;
2511 : : break;
2512 : : }
2513 : : spin_unlock(&inode->i_lock);
2514 : 0 : return result;
2515 : : }
2516 : :
2517 : : EXPORT_SYMBOL(lock_may_write);
2518 : :
2519 : 0 : static int __init filelock_init(void)
2520 : : {
2521 : : int i;
2522 : :
2523 : 0 : filelock_cache = kmem_cache_create("file_lock_cache",
2524 : : sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2525 : :
2526 : 0 : lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2527 : :
2528 [ # # ]: 0 : for_each_possible_cpu(i)
2529 : 0 : INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2530 : :
2531 : 0 : return 0;
2532 : : }
2533 : :
2534 : : core_initcall(filelock_init);
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