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Commit | Line | Data |
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1da177e4 LT |
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/mandatory.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/fs.h> | |
120 | #include <linux/init.h> | |
121 | #include <linux/module.h> | |
122 | #include <linux/security.h> | |
123 | #include <linux/slab.h> | |
124 | #include <linux/smp_lock.h> | |
125 | #include <linux/syscalls.h> | |
126 | #include <linux/time.h> | |
4fb3a538 | 127 | #include <linux/rcupdate.h> |
1da177e4 LT |
128 | |
129 | #include <asm/semaphore.h> | |
130 | #include <asm/uaccess.h> | |
131 | ||
132 | #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX) | |
133 | #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK) | |
134 | #define IS_LEASE(fl) (fl->fl_flags & FL_LEASE) | |
135 | ||
136 | int leases_enable = 1; | |
137 | int lease_break_time = 45; | |
138 | ||
139 | #define for_each_lock(inode, lockp) \ | |
140 | for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) | |
141 | ||
26bcbf96 | 142 | static LIST_HEAD(file_lock_list); |
1da177e4 LT |
143 | static LIST_HEAD(blocked_list); |
144 | ||
e18b890b | 145 | static struct kmem_cache *filelock_cache __read_mostly; |
1da177e4 LT |
146 | |
147 | /* Allocate an empty lock structure. */ | |
148 | static struct file_lock *locks_alloc_lock(void) | |
149 | { | |
e94b1766 | 150 | return kmem_cache_alloc(filelock_cache, GFP_KERNEL); |
1da177e4 LT |
151 | } |
152 | ||
47831f35 TM |
153 | static void locks_release_private(struct file_lock *fl) |
154 | { | |
155 | if (fl->fl_ops) { | |
156 | if (fl->fl_ops->fl_release_private) | |
157 | fl->fl_ops->fl_release_private(fl); | |
158 | fl->fl_ops = NULL; | |
159 | } | |
160 | if (fl->fl_lmops) { | |
161 | if (fl->fl_lmops->fl_release_private) | |
162 | fl->fl_lmops->fl_release_private(fl); | |
163 | fl->fl_lmops = NULL; | |
164 | } | |
165 | ||
166 | } | |
167 | ||
1da177e4 | 168 | /* Free a lock which is not in use. */ |
33443c42 | 169 | static void locks_free_lock(struct file_lock *fl) |
1da177e4 | 170 | { |
5ce29646 MS |
171 | BUG_ON(waitqueue_active(&fl->fl_wait)); |
172 | BUG_ON(!list_empty(&fl->fl_block)); | |
173 | BUG_ON(!list_empty(&fl->fl_link)); | |
1da177e4 | 174 | |
47831f35 | 175 | locks_release_private(fl); |
1da177e4 LT |
176 | kmem_cache_free(filelock_cache, fl); |
177 | } | |
178 | ||
179 | void locks_init_lock(struct file_lock *fl) | |
180 | { | |
181 | INIT_LIST_HEAD(&fl->fl_link); | |
182 | INIT_LIST_HEAD(&fl->fl_block); | |
183 | init_waitqueue_head(&fl->fl_wait); | |
184 | fl->fl_next = NULL; | |
185 | fl->fl_fasync = NULL; | |
186 | fl->fl_owner = NULL; | |
187 | fl->fl_pid = 0; | |
188 | fl->fl_file = NULL; | |
189 | fl->fl_flags = 0; | |
190 | fl->fl_type = 0; | |
191 | fl->fl_start = fl->fl_end = 0; | |
192 | fl->fl_ops = NULL; | |
193 | fl->fl_lmops = NULL; | |
194 | } | |
195 | ||
196 | EXPORT_SYMBOL(locks_init_lock); | |
197 | ||
198 | /* | |
199 | * Initialises the fields of the file lock which are invariant for | |
200 | * free file_locks. | |
201 | */ | |
e18b890b | 202 | static void init_once(void *foo, struct kmem_cache *cache, unsigned long flags) |
1da177e4 LT |
203 | { |
204 | struct file_lock *lock = (struct file_lock *) foo; | |
205 | ||
1da177e4 LT |
206 | locks_init_lock(lock); |
207 | } | |
208 | ||
47831f35 TM |
209 | static void locks_copy_private(struct file_lock *new, struct file_lock *fl) |
210 | { | |
211 | if (fl->fl_ops) { | |
212 | if (fl->fl_ops->fl_copy_lock) | |
213 | fl->fl_ops->fl_copy_lock(new, fl); | |
214 | new->fl_ops = fl->fl_ops; | |
215 | } | |
216 | if (fl->fl_lmops) { | |
217 | if (fl->fl_lmops->fl_copy_lock) | |
218 | fl->fl_lmops->fl_copy_lock(new, fl); | |
219 | new->fl_lmops = fl->fl_lmops; | |
220 | } | |
221 | } | |
222 | ||
1da177e4 LT |
223 | /* |
224 | * Initialize a new lock from an existing file_lock structure. | |
225 | */ | |
0996905f | 226 | static void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl) |
1da177e4 LT |
227 | { |
228 | new->fl_owner = fl->fl_owner; | |
229 | new->fl_pid = fl->fl_pid; | |
0996905f | 230 | new->fl_file = NULL; |
1da177e4 LT |
231 | new->fl_flags = fl->fl_flags; |
232 | new->fl_type = fl->fl_type; | |
233 | new->fl_start = fl->fl_start; | |
234 | new->fl_end = fl->fl_end; | |
0996905f TM |
235 | new->fl_ops = NULL; |
236 | new->fl_lmops = NULL; | |
237 | } | |
238 | ||
239 | void locks_copy_lock(struct file_lock *new, struct file_lock *fl) | |
240 | { | |
241 | locks_release_private(new); | |
242 | ||
243 | __locks_copy_lock(new, fl); | |
244 | new->fl_file = fl->fl_file; | |
1da177e4 LT |
245 | new->fl_ops = fl->fl_ops; |
246 | new->fl_lmops = fl->fl_lmops; | |
47831f35 TM |
247 | |
248 | locks_copy_private(new, fl); | |
1da177e4 LT |
249 | } |
250 | ||
251 | EXPORT_SYMBOL(locks_copy_lock); | |
252 | ||
253 | static inline int flock_translate_cmd(int cmd) { | |
254 | if (cmd & LOCK_MAND) | |
255 | return cmd & (LOCK_MAND | LOCK_RW); | |
256 | switch (cmd) { | |
257 | case LOCK_SH: | |
258 | return F_RDLCK; | |
259 | case LOCK_EX: | |
260 | return F_WRLCK; | |
261 | case LOCK_UN: | |
262 | return F_UNLCK; | |
263 | } | |
264 | return -EINVAL; | |
265 | } | |
266 | ||
267 | /* Fill in a file_lock structure with an appropriate FLOCK lock. */ | |
268 | static int flock_make_lock(struct file *filp, struct file_lock **lock, | |
269 | unsigned int cmd) | |
270 | { | |
271 | struct file_lock *fl; | |
272 | int type = flock_translate_cmd(cmd); | |
273 | if (type < 0) | |
274 | return type; | |
275 | ||
276 | fl = locks_alloc_lock(); | |
277 | if (fl == NULL) | |
278 | return -ENOMEM; | |
279 | ||
280 | fl->fl_file = filp; | |
281 | fl->fl_pid = current->tgid; | |
282 | fl->fl_flags = FL_FLOCK; | |
283 | fl->fl_type = type; | |
284 | fl->fl_end = OFFSET_MAX; | |
285 | ||
286 | *lock = fl; | |
287 | return 0; | |
288 | } | |
289 | ||
290 | static int assign_type(struct file_lock *fl, int type) | |
291 | { | |
292 | switch (type) { | |
293 | case F_RDLCK: | |
294 | case F_WRLCK: | |
295 | case F_UNLCK: | |
296 | fl->fl_type = type; | |
297 | break; | |
298 | default: | |
299 | return -EINVAL; | |
300 | } | |
301 | return 0; | |
302 | } | |
303 | ||
304 | /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX | |
305 | * style lock. | |
306 | */ | |
307 | static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, | |
308 | struct flock *l) | |
309 | { | |
310 | off_t start, end; | |
311 | ||
312 | switch (l->l_whence) { | |
f5579f8c | 313 | case SEEK_SET: |
1da177e4 LT |
314 | start = 0; |
315 | break; | |
f5579f8c | 316 | case SEEK_CUR: |
1da177e4 LT |
317 | start = filp->f_pos; |
318 | break; | |
f5579f8c | 319 | case SEEK_END: |
0f7fc9e4 | 320 | start = i_size_read(filp->f_path.dentry->d_inode); |
1da177e4 LT |
321 | break; |
322 | default: | |
323 | return -EINVAL; | |
324 | } | |
325 | ||
326 | /* POSIX-1996 leaves the case l->l_len < 0 undefined; | |
327 | POSIX-2001 defines it. */ | |
328 | start += l->l_start; | |
4c780a46 TM |
329 | if (start < 0) |
330 | return -EINVAL; | |
331 | fl->fl_end = OFFSET_MAX; | |
332 | if (l->l_len > 0) { | |
333 | end = start + l->l_len - 1; | |
334 | fl->fl_end = end; | |
335 | } else if (l->l_len < 0) { | |
1da177e4 | 336 | end = start - 1; |
4c780a46 | 337 | fl->fl_end = end; |
1da177e4 | 338 | start += l->l_len; |
4c780a46 TM |
339 | if (start < 0) |
340 | return -EINVAL; | |
1da177e4 | 341 | } |
1da177e4 | 342 | fl->fl_start = start; /* we record the absolute position */ |
4c780a46 TM |
343 | if (fl->fl_end < fl->fl_start) |
344 | return -EOVERFLOW; | |
1da177e4 LT |
345 | |
346 | fl->fl_owner = current->files; | |
347 | fl->fl_pid = current->tgid; | |
348 | fl->fl_file = filp; | |
349 | fl->fl_flags = FL_POSIX; | |
350 | fl->fl_ops = NULL; | |
351 | fl->fl_lmops = NULL; | |
352 | ||
353 | return assign_type(fl, l->l_type); | |
354 | } | |
355 | ||
356 | #if BITS_PER_LONG == 32 | |
357 | static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, | |
358 | struct flock64 *l) | |
359 | { | |
360 | loff_t start; | |
361 | ||
362 | switch (l->l_whence) { | |
f5579f8c | 363 | case SEEK_SET: |
1da177e4 LT |
364 | start = 0; |
365 | break; | |
f5579f8c | 366 | case SEEK_CUR: |
1da177e4 LT |
367 | start = filp->f_pos; |
368 | break; | |
f5579f8c | 369 | case SEEK_END: |
0f7fc9e4 | 370 | start = i_size_read(filp->f_path.dentry->d_inode); |
1da177e4 LT |
371 | break; |
372 | default: | |
373 | return -EINVAL; | |
374 | } | |
375 | ||
4c780a46 TM |
376 | start += l->l_start; |
377 | if (start < 0) | |
1da177e4 | 378 | return -EINVAL; |
4c780a46 TM |
379 | fl->fl_end = OFFSET_MAX; |
380 | if (l->l_len > 0) { | |
381 | fl->fl_end = start + l->l_len - 1; | |
382 | } else if (l->l_len < 0) { | |
383 | fl->fl_end = start - 1; | |
384 | start += l->l_len; | |
385 | if (start < 0) | |
386 | return -EINVAL; | |
387 | } | |
1da177e4 | 388 | fl->fl_start = start; /* we record the absolute position */ |
4c780a46 TM |
389 | if (fl->fl_end < fl->fl_start) |
390 | return -EOVERFLOW; | |
1da177e4 LT |
391 | |
392 | fl->fl_owner = current->files; | |
393 | fl->fl_pid = current->tgid; | |
394 | fl->fl_file = filp; | |
395 | fl->fl_flags = FL_POSIX; | |
396 | fl->fl_ops = NULL; | |
397 | fl->fl_lmops = NULL; | |
398 | ||
399 | switch (l->l_type) { | |
400 | case F_RDLCK: | |
401 | case F_WRLCK: | |
402 | case F_UNLCK: | |
403 | fl->fl_type = l->l_type; | |
404 | break; | |
405 | default: | |
406 | return -EINVAL; | |
407 | } | |
408 | ||
409 | return (0); | |
410 | } | |
411 | #endif | |
412 | ||
413 | /* default lease lock manager operations */ | |
414 | static void lease_break_callback(struct file_lock *fl) | |
415 | { | |
416 | kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG); | |
417 | } | |
418 | ||
419 | static void lease_release_private_callback(struct file_lock *fl) | |
420 | { | |
421 | if (!fl->fl_file) | |
422 | return; | |
423 | ||
424 | f_delown(fl->fl_file); | |
425 | fl->fl_file->f_owner.signum = 0; | |
426 | } | |
427 | ||
75c96f85 | 428 | static int lease_mylease_callback(struct file_lock *fl, struct file_lock *try) |
1da177e4 LT |
429 | { |
430 | return fl->fl_file == try->fl_file; | |
431 | } | |
432 | ||
75c96f85 | 433 | static struct lock_manager_operations lease_manager_ops = { |
1da177e4 LT |
434 | .fl_break = lease_break_callback, |
435 | .fl_release_private = lease_release_private_callback, | |
436 | .fl_mylease = lease_mylease_callback, | |
437 | .fl_change = lease_modify, | |
438 | }; | |
439 | ||
440 | /* | |
441 | * Initialize a lease, use the default lock manager operations | |
442 | */ | |
443 | static int lease_init(struct file *filp, int type, struct file_lock *fl) | |
444 | { | |
75dff55a TM |
445 | if (assign_type(fl, type) != 0) |
446 | return -EINVAL; | |
447 | ||
1da177e4 LT |
448 | fl->fl_owner = current->files; |
449 | fl->fl_pid = current->tgid; | |
450 | ||
451 | fl->fl_file = filp; | |
452 | fl->fl_flags = FL_LEASE; | |
1da177e4 LT |
453 | fl->fl_start = 0; |
454 | fl->fl_end = OFFSET_MAX; | |
455 | fl->fl_ops = NULL; | |
456 | fl->fl_lmops = &lease_manager_ops; | |
457 | return 0; | |
458 | } | |
459 | ||
460 | /* Allocate a file_lock initialised to this type of lease */ | |
e32b8ee2 | 461 | static struct file_lock *lease_alloc(struct file *filp, int type) |
1da177e4 LT |
462 | { |
463 | struct file_lock *fl = locks_alloc_lock(); | |
75dff55a | 464 | int error = -ENOMEM; |
1da177e4 LT |
465 | |
466 | if (fl == NULL) | |
e32b8ee2 | 467 | return ERR_PTR(error); |
1da177e4 LT |
468 | |
469 | error = lease_init(filp, type, fl); | |
75dff55a TM |
470 | if (error) { |
471 | locks_free_lock(fl); | |
e32b8ee2 | 472 | return ERR_PTR(error); |
75dff55a | 473 | } |
e32b8ee2 | 474 | return fl; |
1da177e4 LT |
475 | } |
476 | ||
477 | /* Check if two locks overlap each other. | |
478 | */ | |
479 | static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2) | |
480 | { | |
481 | return ((fl1->fl_end >= fl2->fl_start) && | |
482 | (fl2->fl_end >= fl1->fl_start)); | |
483 | } | |
484 | ||
485 | /* | |
486 | * Check whether two locks have the same owner. | |
487 | */ | |
33443c42 | 488 | static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) |
1da177e4 LT |
489 | { |
490 | if (fl1->fl_lmops && fl1->fl_lmops->fl_compare_owner) | |
491 | return fl2->fl_lmops == fl1->fl_lmops && | |
492 | fl1->fl_lmops->fl_compare_owner(fl1, fl2); | |
493 | return fl1->fl_owner == fl2->fl_owner; | |
494 | } | |
495 | ||
496 | /* Remove waiter from blocker's block list. | |
497 | * When blocker ends up pointing to itself then the list is empty. | |
498 | */ | |
33443c42 | 499 | static void __locks_delete_block(struct file_lock *waiter) |
1da177e4 LT |
500 | { |
501 | list_del_init(&waiter->fl_block); | |
502 | list_del_init(&waiter->fl_link); | |
503 | waiter->fl_next = NULL; | |
504 | } | |
505 | ||
506 | /* | |
507 | */ | |
508 | static void locks_delete_block(struct file_lock *waiter) | |
509 | { | |
510 | lock_kernel(); | |
511 | __locks_delete_block(waiter); | |
512 | unlock_kernel(); | |
513 | } | |
514 | ||
515 | /* Insert waiter into blocker's block list. | |
516 | * We use a circular list so that processes can be easily woken up in | |
517 | * the order they blocked. The documentation doesn't require this but | |
518 | * it seems like the reasonable thing to do. | |
519 | */ | |
520 | static void locks_insert_block(struct file_lock *blocker, | |
521 | struct file_lock *waiter) | |
522 | { | |
6dc0fe8f | 523 | BUG_ON(!list_empty(&waiter->fl_block)); |
1da177e4 LT |
524 | list_add_tail(&waiter->fl_block, &blocker->fl_block); |
525 | waiter->fl_next = blocker; | |
526 | if (IS_POSIX(blocker)) | |
527 | list_add(&waiter->fl_link, &blocked_list); | |
528 | } | |
529 | ||
530 | /* Wake up processes blocked waiting for blocker. | |
531 | * If told to wait then schedule the processes until the block list | |
532 | * is empty, otherwise empty the block list ourselves. | |
533 | */ | |
534 | static void locks_wake_up_blocks(struct file_lock *blocker) | |
535 | { | |
536 | while (!list_empty(&blocker->fl_block)) { | |
f0c1cd0e PE |
537 | struct file_lock *waiter; |
538 | ||
539 | waiter = list_first_entry(&blocker->fl_block, | |
1da177e4 LT |
540 | struct file_lock, fl_block); |
541 | __locks_delete_block(waiter); | |
542 | if (waiter->fl_lmops && waiter->fl_lmops->fl_notify) | |
543 | waiter->fl_lmops->fl_notify(waiter); | |
544 | else | |
545 | wake_up(&waiter->fl_wait); | |
546 | } | |
547 | } | |
548 | ||
549 | /* Insert file lock fl into an inode's lock list at the position indicated | |
550 | * by pos. At the same time add the lock to the global file lock list. | |
551 | */ | |
552 | static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl) | |
553 | { | |
554 | list_add(&fl->fl_link, &file_lock_list); | |
555 | ||
556 | /* insert into file's list */ | |
557 | fl->fl_next = *pos; | |
558 | *pos = fl; | |
559 | ||
560 | if (fl->fl_ops && fl->fl_ops->fl_insert) | |
561 | fl->fl_ops->fl_insert(fl); | |
562 | } | |
563 | ||
564 | /* | |
565 | * Delete a lock and then free it. | |
566 | * Wake up processes that are blocked waiting for this lock, | |
567 | * notify the FS that the lock has been cleared and | |
568 | * finally free the lock. | |
569 | */ | |
570 | static void locks_delete_lock(struct file_lock **thisfl_p) | |
571 | { | |
572 | struct file_lock *fl = *thisfl_p; | |
573 | ||
574 | *thisfl_p = fl->fl_next; | |
575 | fl->fl_next = NULL; | |
576 | list_del_init(&fl->fl_link); | |
577 | ||
578 | fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync); | |
579 | if (fl->fl_fasync != NULL) { | |
580 | printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync); | |
581 | fl->fl_fasync = NULL; | |
582 | } | |
583 | ||
584 | if (fl->fl_ops && fl->fl_ops->fl_remove) | |
585 | fl->fl_ops->fl_remove(fl); | |
586 | ||
587 | locks_wake_up_blocks(fl); | |
588 | locks_free_lock(fl); | |
589 | } | |
590 | ||
591 | /* Determine if lock sys_fl blocks lock caller_fl. Common functionality | |
592 | * checks for shared/exclusive status of overlapping locks. | |
593 | */ | |
594 | static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
595 | { | |
596 | if (sys_fl->fl_type == F_WRLCK) | |
597 | return 1; | |
598 | if (caller_fl->fl_type == F_WRLCK) | |
599 | return 1; | |
600 | return 0; | |
601 | } | |
602 | ||
603 | /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific | |
604 | * checking before calling the locks_conflict(). | |
605 | */ | |
606 | static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
607 | { | |
608 | /* POSIX locks owned by the same process do not conflict with | |
609 | * each other. | |
610 | */ | |
611 | if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl)) | |
612 | return (0); | |
613 | ||
614 | /* Check whether they overlap */ | |
615 | if (!locks_overlap(caller_fl, sys_fl)) | |
616 | return 0; | |
617 | ||
618 | return (locks_conflict(caller_fl, sys_fl)); | |
619 | } | |
620 | ||
621 | /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific | |
622 | * checking before calling the locks_conflict(). | |
623 | */ | |
624 | static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
625 | { | |
626 | /* FLOCK locks referring to the same filp do not conflict with | |
627 | * each other. | |
628 | */ | |
629 | if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file)) | |
630 | return (0); | |
631 | if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND)) | |
632 | return 0; | |
633 | ||
634 | return (locks_conflict(caller_fl, sys_fl)); | |
635 | } | |
636 | ||
637 | static int interruptible_sleep_on_locked(wait_queue_head_t *fl_wait, int timeout) | |
638 | { | |
639 | int result = 0; | |
640 | DECLARE_WAITQUEUE(wait, current); | |
641 | ||
642 | __set_current_state(TASK_INTERRUPTIBLE); | |
643 | add_wait_queue(fl_wait, &wait); | |
644 | if (timeout == 0) | |
645 | schedule(); | |
646 | else | |
647 | result = schedule_timeout(timeout); | |
648 | if (signal_pending(current)) | |
649 | result = -ERESTARTSYS; | |
650 | remove_wait_queue(fl_wait, &wait); | |
651 | __set_current_state(TASK_RUNNING); | |
652 | return result; | |
653 | } | |
654 | ||
655 | static int locks_block_on_timeout(struct file_lock *blocker, struct file_lock *waiter, int time) | |
656 | { | |
657 | int result; | |
658 | locks_insert_block(blocker, waiter); | |
659 | result = interruptible_sleep_on_locked(&waiter->fl_wait, time); | |
660 | __locks_delete_block(waiter); | |
661 | return result; | |
662 | } | |
663 | ||
6d34ac19 | 664 | void |
9d6a8c5c | 665 | posix_test_lock(struct file *filp, struct file_lock *fl) |
1da177e4 LT |
666 | { |
667 | struct file_lock *cfl; | |
668 | ||
669 | lock_kernel(); | |
0f7fc9e4 | 670 | for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) { |
1da177e4 LT |
671 | if (!IS_POSIX(cfl)) |
672 | continue; | |
b842e240 | 673 | if (posix_locks_conflict(fl, cfl)) |
1da177e4 LT |
674 | break; |
675 | } | |
6d34ac19 | 676 | if (cfl) |
9d6a8c5c | 677 | __locks_copy_lock(fl, cfl); |
6d34ac19 | 678 | else |
129a84de | 679 | fl->fl_type = F_UNLCK; |
1da177e4 | 680 | unlock_kernel(); |
6d34ac19 | 681 | return; |
1da177e4 LT |
682 | } |
683 | ||
684 | EXPORT_SYMBOL(posix_test_lock); | |
685 | ||
686 | /* This function tests for deadlock condition before putting a process to | |
687 | * sleep. The detection scheme is no longer recursive. Recursive was neat, | |
688 | * but dangerous - we risked stack corruption if the lock data was bad, or | |
689 | * if the recursion was too deep for any other reason. | |
690 | * | |
691 | * We rely on the fact that a task can only be on one lock's wait queue | |
692 | * at a time. When we find blocked_task on a wait queue we can re-search | |
693 | * with blocked_task equal to that queue's owner, until either blocked_task | |
694 | * isn't found, or blocked_task is found on a queue owned by my_task. | |
695 | * | |
696 | * Note: the above assumption may not be true when handling lock requests | |
697 | * from a broken NFS client. But broken NFS clients have a lot more to | |
698 | * worry about than proper deadlock detection anyway... --okir | |
699 | */ | |
b0904e14 | 700 | static int posix_locks_deadlock(struct file_lock *caller_fl, |
1da177e4 LT |
701 | struct file_lock *block_fl) |
702 | { | |
094f2825 | 703 | struct file_lock *fl; |
1da177e4 LT |
704 | |
705 | next_task: | |
706 | if (posix_same_owner(caller_fl, block_fl)) | |
707 | return 1; | |
094f2825 | 708 | list_for_each_entry(fl, &blocked_list, fl_link) { |
1da177e4 LT |
709 | if (posix_same_owner(fl, block_fl)) { |
710 | fl = fl->fl_next; | |
711 | block_fl = fl; | |
712 | goto next_task; | |
713 | } | |
714 | } | |
715 | return 0; | |
716 | } | |
717 | ||
1da177e4 | 718 | /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks |
02888f41 | 719 | * after any leases, but before any posix locks. |
f475ae95 TM |
720 | * |
721 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
722 | * whether or not a lock was successfully freed by testing the return | |
723 | * value for -ENOENT. | |
1da177e4 | 724 | */ |
993dfa87 | 725 | static int flock_lock_file(struct file *filp, struct file_lock *request) |
1da177e4 | 726 | { |
993dfa87 | 727 | struct file_lock *new_fl = NULL; |
1da177e4 | 728 | struct file_lock **before; |
0f7fc9e4 | 729 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
730 | int error = 0; |
731 | int found = 0; | |
732 | ||
733 | lock_kernel(); | |
f07f18dd TM |
734 | if (request->fl_flags & FL_ACCESS) |
735 | goto find_conflict; | |
84d535ad PE |
736 | |
737 | if (request->fl_type != F_UNLCK) { | |
738 | error = -ENOMEM; | |
739 | new_fl = locks_alloc_lock(); | |
740 | if (new_fl == NULL) | |
741 | goto out; | |
742 | error = 0; | |
743 | } | |
744 | ||
1da177e4 LT |
745 | for_each_lock(inode, before) { |
746 | struct file_lock *fl = *before; | |
747 | if (IS_POSIX(fl)) | |
748 | break; | |
749 | if (IS_LEASE(fl)) | |
750 | continue; | |
751 | if (filp != fl->fl_file) | |
752 | continue; | |
993dfa87 | 753 | if (request->fl_type == fl->fl_type) |
1da177e4 LT |
754 | goto out; |
755 | found = 1; | |
756 | locks_delete_lock(before); | |
757 | break; | |
758 | } | |
1da177e4 | 759 | |
f475ae95 TM |
760 | if (request->fl_type == F_UNLCK) { |
761 | if ((request->fl_flags & FL_EXISTS) && !found) | |
762 | error = -ENOENT; | |
993dfa87 | 763 | goto out; |
f475ae95 | 764 | } |
1da177e4 LT |
765 | |
766 | /* | |
767 | * If a higher-priority process was blocked on the old file lock, | |
768 | * give it the opportunity to lock the file. | |
769 | */ | |
770 | if (found) | |
771 | cond_resched(); | |
772 | ||
f07f18dd | 773 | find_conflict: |
1da177e4 LT |
774 | for_each_lock(inode, before) { |
775 | struct file_lock *fl = *before; | |
776 | if (IS_POSIX(fl)) | |
777 | break; | |
778 | if (IS_LEASE(fl)) | |
779 | continue; | |
993dfa87 | 780 | if (!flock_locks_conflict(request, fl)) |
1da177e4 LT |
781 | continue; |
782 | error = -EAGAIN; | |
993dfa87 TM |
783 | if (request->fl_flags & FL_SLEEP) |
784 | locks_insert_block(fl, request); | |
1da177e4 LT |
785 | goto out; |
786 | } | |
f07f18dd TM |
787 | if (request->fl_flags & FL_ACCESS) |
788 | goto out; | |
993dfa87 | 789 | locks_copy_lock(new_fl, request); |
0e2f6db8 | 790 | locks_insert_lock(before, new_fl); |
993dfa87 | 791 | new_fl = NULL; |
9cedc194 | 792 | error = 0; |
1da177e4 LT |
793 | |
794 | out: | |
795 | unlock_kernel(); | |
993dfa87 TM |
796 | if (new_fl) |
797 | locks_free_lock(new_fl); | |
1da177e4 LT |
798 | return error; |
799 | } | |
800 | ||
150b3934 | 801 | static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock) |
1da177e4 LT |
802 | { |
803 | struct file_lock *fl; | |
39005d02 MS |
804 | struct file_lock *new_fl = NULL; |
805 | struct file_lock *new_fl2 = NULL; | |
1da177e4 LT |
806 | struct file_lock *left = NULL; |
807 | struct file_lock *right = NULL; | |
808 | struct file_lock **before; | |
809 | int error, added = 0; | |
810 | ||
811 | /* | |
812 | * We may need two file_lock structures for this operation, | |
813 | * so we get them in advance to avoid races. | |
39005d02 MS |
814 | * |
815 | * In some cases we can be sure, that no new locks will be needed | |
1da177e4 | 816 | */ |
39005d02 MS |
817 | if (!(request->fl_flags & FL_ACCESS) && |
818 | (request->fl_type != F_UNLCK || | |
819 | request->fl_start != 0 || request->fl_end != OFFSET_MAX)) { | |
820 | new_fl = locks_alloc_lock(); | |
821 | new_fl2 = locks_alloc_lock(); | |
822 | } | |
1da177e4 LT |
823 | |
824 | lock_kernel(); | |
825 | if (request->fl_type != F_UNLCK) { | |
826 | for_each_lock(inode, before) { | |
526985b9 | 827 | fl = *before; |
1da177e4 LT |
828 | if (!IS_POSIX(fl)) |
829 | continue; | |
830 | if (!posix_locks_conflict(request, fl)) | |
831 | continue; | |
5842add2 AA |
832 | if (conflock) |
833 | locks_copy_lock(conflock, fl); | |
1da177e4 LT |
834 | error = -EAGAIN; |
835 | if (!(request->fl_flags & FL_SLEEP)) | |
836 | goto out; | |
837 | error = -EDEADLK; | |
838 | if (posix_locks_deadlock(request, fl)) | |
839 | goto out; | |
840 | error = -EAGAIN; | |
841 | locks_insert_block(fl, request); | |
842 | goto out; | |
843 | } | |
844 | } | |
845 | ||
846 | /* If we're just looking for a conflict, we're done. */ | |
847 | error = 0; | |
848 | if (request->fl_flags & FL_ACCESS) | |
849 | goto out; | |
850 | ||
1da177e4 | 851 | /* |
1da177e4 LT |
852 | * Find the first old lock with the same owner as the new lock. |
853 | */ | |
854 | ||
855 | before = &inode->i_flock; | |
856 | ||
857 | /* First skip locks owned by other processes. */ | |
858 | while ((fl = *before) && (!IS_POSIX(fl) || | |
859 | !posix_same_owner(request, fl))) { | |
860 | before = &fl->fl_next; | |
861 | } | |
862 | ||
863 | /* Process locks with this owner. */ | |
864 | while ((fl = *before) && posix_same_owner(request, fl)) { | |
865 | /* Detect adjacent or overlapping regions (if same lock type) | |
866 | */ | |
867 | if (request->fl_type == fl->fl_type) { | |
449231d6 OK |
868 | /* In all comparisons of start vs end, use |
869 | * "start - 1" rather than "end + 1". If end | |
870 | * is OFFSET_MAX, end + 1 will become negative. | |
871 | */ | |
1da177e4 LT |
872 | if (fl->fl_end < request->fl_start - 1) |
873 | goto next_lock; | |
874 | /* If the next lock in the list has entirely bigger | |
875 | * addresses than the new one, insert the lock here. | |
876 | */ | |
449231d6 | 877 | if (fl->fl_start - 1 > request->fl_end) |
1da177e4 LT |
878 | break; |
879 | ||
880 | /* If we come here, the new and old lock are of the | |
881 | * same type and adjacent or overlapping. Make one | |
882 | * lock yielding from the lower start address of both | |
883 | * locks to the higher end address. | |
884 | */ | |
885 | if (fl->fl_start > request->fl_start) | |
886 | fl->fl_start = request->fl_start; | |
887 | else | |
888 | request->fl_start = fl->fl_start; | |
889 | if (fl->fl_end < request->fl_end) | |
890 | fl->fl_end = request->fl_end; | |
891 | else | |
892 | request->fl_end = fl->fl_end; | |
893 | if (added) { | |
894 | locks_delete_lock(before); | |
895 | continue; | |
896 | } | |
897 | request = fl; | |
898 | added = 1; | |
899 | } | |
900 | else { | |
901 | /* Processing for different lock types is a bit | |
902 | * more complex. | |
903 | */ | |
904 | if (fl->fl_end < request->fl_start) | |
905 | goto next_lock; | |
906 | if (fl->fl_start > request->fl_end) | |
907 | break; | |
908 | if (request->fl_type == F_UNLCK) | |
909 | added = 1; | |
910 | if (fl->fl_start < request->fl_start) | |
911 | left = fl; | |
912 | /* If the next lock in the list has a higher end | |
913 | * address than the new one, insert the new one here. | |
914 | */ | |
915 | if (fl->fl_end > request->fl_end) { | |
916 | right = fl; | |
917 | break; | |
918 | } | |
919 | if (fl->fl_start >= request->fl_start) { | |
920 | /* The new lock completely replaces an old | |
921 | * one (This may happen several times). | |
922 | */ | |
923 | if (added) { | |
924 | locks_delete_lock(before); | |
925 | continue; | |
926 | } | |
927 | /* Replace the old lock with the new one. | |
928 | * Wake up anybody waiting for the old one, | |
929 | * as the change in lock type might satisfy | |
930 | * their needs. | |
931 | */ | |
932 | locks_wake_up_blocks(fl); | |
933 | fl->fl_start = request->fl_start; | |
934 | fl->fl_end = request->fl_end; | |
935 | fl->fl_type = request->fl_type; | |
47831f35 TM |
936 | locks_release_private(fl); |
937 | locks_copy_private(fl, request); | |
1da177e4 LT |
938 | request = fl; |
939 | added = 1; | |
940 | } | |
941 | } | |
942 | /* Go on to next lock. | |
943 | */ | |
944 | next_lock: | |
945 | before = &fl->fl_next; | |
946 | } | |
947 | ||
0d9a490a MS |
948 | /* |
949 | * The above code only modifies existing locks in case of | |
950 | * merging or replacing. If new lock(s) need to be inserted | |
951 | * all modifications are done bellow this, so it's safe yet to | |
952 | * bail out. | |
953 | */ | |
954 | error = -ENOLCK; /* "no luck" */ | |
955 | if (right && left == right && !new_fl2) | |
956 | goto out; | |
957 | ||
1da177e4 LT |
958 | error = 0; |
959 | if (!added) { | |
f475ae95 TM |
960 | if (request->fl_type == F_UNLCK) { |
961 | if (request->fl_flags & FL_EXISTS) | |
962 | error = -ENOENT; | |
1da177e4 | 963 | goto out; |
f475ae95 | 964 | } |
0d9a490a MS |
965 | |
966 | if (!new_fl) { | |
967 | error = -ENOLCK; | |
968 | goto out; | |
969 | } | |
1da177e4 LT |
970 | locks_copy_lock(new_fl, request); |
971 | locks_insert_lock(before, new_fl); | |
972 | new_fl = NULL; | |
973 | } | |
974 | if (right) { | |
975 | if (left == right) { | |
976 | /* The new lock breaks the old one in two pieces, | |
977 | * so we have to use the second new lock. | |
978 | */ | |
979 | left = new_fl2; | |
980 | new_fl2 = NULL; | |
981 | locks_copy_lock(left, right); | |
982 | locks_insert_lock(before, left); | |
983 | } | |
984 | right->fl_start = request->fl_end + 1; | |
985 | locks_wake_up_blocks(right); | |
986 | } | |
987 | if (left) { | |
988 | left->fl_end = request->fl_start - 1; | |
989 | locks_wake_up_blocks(left); | |
990 | } | |
991 | out: | |
992 | unlock_kernel(); | |
993 | /* | |
994 | * Free any unused locks. | |
995 | */ | |
996 | if (new_fl) | |
997 | locks_free_lock(new_fl); | |
998 | if (new_fl2) | |
999 | locks_free_lock(new_fl2); | |
1000 | return error; | |
1001 | } | |
1002 | ||
1003 | /** | |
1004 | * posix_lock_file - Apply a POSIX-style lock to a file | |
1005 | * @filp: The file to apply the lock to | |
1006 | * @fl: The lock to be applied | |
150b3934 | 1007 | * @conflock: Place to return a copy of the conflicting lock, if found. |
1da177e4 LT |
1008 | * |
1009 | * Add a POSIX style lock to a file. | |
1010 | * We merge adjacent & overlapping locks whenever possible. | |
1011 | * POSIX locks are sorted by owner task, then by starting address | |
f475ae95 TM |
1012 | * |
1013 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
1014 | * whether or not a lock was successfully freed by testing the return | |
1015 | * value for -ENOENT. | |
1da177e4 | 1016 | */ |
150b3934 | 1017 | int posix_lock_file(struct file *filp, struct file_lock *fl, |
5842add2 AA |
1018 | struct file_lock *conflock) |
1019 | { | |
150b3934 | 1020 | return __posix_lock_file(filp->f_path.dentry->d_inode, fl, conflock); |
1da177e4 | 1021 | } |
150b3934 | 1022 | EXPORT_SYMBOL(posix_lock_file); |
1da177e4 LT |
1023 | |
1024 | /** | |
1025 | * posix_lock_file_wait - Apply a POSIX-style lock to a file | |
1026 | * @filp: The file to apply the lock to | |
1027 | * @fl: The lock to be applied | |
1028 | * | |
1029 | * Add a POSIX style lock to a file. | |
1030 | * We merge adjacent & overlapping locks whenever possible. | |
1031 | * POSIX locks are sorted by owner task, then by starting address | |
1032 | */ | |
1033 | int posix_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1034 | { | |
1035 | int error; | |
1036 | might_sleep (); | |
1037 | for (;;) { | |
150b3934 | 1038 | error = posix_lock_file(filp, fl, NULL); |
1da177e4 LT |
1039 | if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP)) |
1040 | break; | |
1041 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1042 | if (!error) | |
1043 | continue; | |
1044 | ||
1045 | locks_delete_block(fl); | |
1046 | break; | |
1047 | } | |
1048 | return error; | |
1049 | } | |
1050 | EXPORT_SYMBOL(posix_lock_file_wait); | |
1051 | ||
1052 | /** | |
1053 | * locks_mandatory_locked - Check for an active lock | |
1054 | * @inode: the file to check | |
1055 | * | |
1056 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1057 | * This function is called from locks_verify_locked() only. | |
1058 | */ | |
1059 | int locks_mandatory_locked(struct inode *inode) | |
1060 | { | |
1061 | fl_owner_t owner = current->files; | |
1062 | struct file_lock *fl; | |
1063 | ||
1064 | /* | |
1065 | * Search the lock list for this inode for any POSIX locks. | |
1066 | */ | |
1067 | lock_kernel(); | |
1068 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { | |
1069 | if (!IS_POSIX(fl)) | |
1070 | continue; | |
1071 | if (fl->fl_owner != owner) | |
1072 | break; | |
1073 | } | |
1074 | unlock_kernel(); | |
1075 | return fl ? -EAGAIN : 0; | |
1076 | } | |
1077 | ||
1078 | /** | |
1079 | * locks_mandatory_area - Check for a conflicting lock | |
1080 | * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ | |
1081 | * for shared | |
1082 | * @inode: the file to check | |
1083 | * @filp: how the file was opened (if it was) | |
1084 | * @offset: start of area to check | |
1085 | * @count: length of area to check | |
1086 | * | |
1087 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1088 | * This function is called from rw_verify_area() and | |
1089 | * locks_verify_truncate(). | |
1090 | */ | |
1091 | int locks_mandatory_area(int read_write, struct inode *inode, | |
1092 | struct file *filp, loff_t offset, | |
1093 | size_t count) | |
1094 | { | |
1095 | struct file_lock fl; | |
1096 | int error; | |
1097 | ||
1098 | locks_init_lock(&fl); | |
1099 | fl.fl_owner = current->files; | |
1100 | fl.fl_pid = current->tgid; | |
1101 | fl.fl_file = filp; | |
1102 | fl.fl_flags = FL_POSIX | FL_ACCESS; | |
1103 | if (filp && !(filp->f_flags & O_NONBLOCK)) | |
1104 | fl.fl_flags |= FL_SLEEP; | |
1105 | fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK; | |
1106 | fl.fl_start = offset; | |
1107 | fl.fl_end = offset + count - 1; | |
1108 | ||
1109 | for (;;) { | |
150b3934 | 1110 | error = __posix_lock_file(inode, &fl, NULL); |
1da177e4 LT |
1111 | if (error != -EAGAIN) |
1112 | break; | |
1113 | if (!(fl.fl_flags & FL_SLEEP)) | |
1114 | break; | |
1115 | error = wait_event_interruptible(fl.fl_wait, !fl.fl_next); | |
1116 | if (!error) { | |
1117 | /* | |
1118 | * If we've been sleeping someone might have | |
1119 | * changed the permissions behind our back. | |
1120 | */ | |
a16877ca | 1121 | if (__mandatory_lock(inode)) |
1da177e4 LT |
1122 | continue; |
1123 | } | |
1124 | ||
1125 | locks_delete_block(&fl); | |
1126 | break; | |
1127 | } | |
1128 | ||
1129 | return error; | |
1130 | } | |
1131 | ||
1132 | EXPORT_SYMBOL(locks_mandatory_area); | |
1133 | ||
1134 | /* We already had a lease on this file; just change its type */ | |
1135 | int lease_modify(struct file_lock **before, int arg) | |
1136 | { | |
1137 | struct file_lock *fl = *before; | |
1138 | int error = assign_type(fl, arg); | |
1139 | ||
1140 | if (error) | |
1141 | return error; | |
1142 | locks_wake_up_blocks(fl); | |
1143 | if (arg == F_UNLCK) | |
1144 | locks_delete_lock(before); | |
1145 | return 0; | |
1146 | } | |
1147 | ||
1148 | EXPORT_SYMBOL(lease_modify); | |
1149 | ||
1150 | static void time_out_leases(struct inode *inode) | |
1151 | { | |
1152 | struct file_lock **before; | |
1153 | struct file_lock *fl; | |
1154 | ||
1155 | before = &inode->i_flock; | |
1156 | while ((fl = *before) && IS_LEASE(fl) && (fl->fl_type & F_INPROGRESS)) { | |
1157 | if ((fl->fl_break_time == 0) | |
1158 | || time_before(jiffies, fl->fl_break_time)) { | |
1159 | before = &fl->fl_next; | |
1160 | continue; | |
1161 | } | |
1da177e4 LT |
1162 | lease_modify(before, fl->fl_type & ~F_INPROGRESS); |
1163 | if (fl == *before) /* lease_modify may have freed fl */ | |
1164 | before = &fl->fl_next; | |
1165 | } | |
1166 | } | |
1167 | ||
1168 | /** | |
1169 | * __break_lease - revoke all outstanding leases on file | |
1170 | * @inode: the inode of the file to return | |
1171 | * @mode: the open mode (read or write) | |
1172 | * | |
87250dd2 | 1173 | * break_lease (inlined for speed) has checked there already is at least |
1174 | * some kind of lock (maybe a lease) on this file. Leases are broken on | |
1175 | * a call to open() or truncate(). This function can sleep unless you | |
1da177e4 LT |
1176 | * specified %O_NONBLOCK to your open(). |
1177 | */ | |
1178 | int __break_lease(struct inode *inode, unsigned int mode) | |
1179 | { | |
1180 | int error = 0, future; | |
1181 | struct file_lock *new_fl, *flock; | |
1182 | struct file_lock *fl; | |
1da177e4 LT |
1183 | unsigned long break_time; |
1184 | int i_have_this_lease = 0; | |
1185 | ||
e32b8ee2 | 1186 | new_fl = lease_alloc(NULL, mode & FMODE_WRITE ? F_WRLCK : F_RDLCK); |
1da177e4 LT |
1187 | |
1188 | lock_kernel(); | |
1189 | ||
1190 | time_out_leases(inode); | |
1191 | ||
1192 | flock = inode->i_flock; | |
1193 | if ((flock == NULL) || !IS_LEASE(flock)) | |
1194 | goto out; | |
1195 | ||
1196 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) | |
1197 | if (fl->fl_owner == current->files) | |
1198 | i_have_this_lease = 1; | |
1199 | ||
1200 | if (mode & FMODE_WRITE) { | |
1201 | /* If we want write access, we have to revoke any lease. */ | |
1202 | future = F_UNLCK | F_INPROGRESS; | |
1203 | } else if (flock->fl_type & F_INPROGRESS) { | |
1204 | /* If the lease is already being broken, we just leave it */ | |
1205 | future = flock->fl_type; | |
1206 | } else if (flock->fl_type & F_WRLCK) { | |
1207 | /* Downgrade the exclusive lease to a read-only lease. */ | |
1208 | future = F_RDLCK | F_INPROGRESS; | |
1209 | } else { | |
1210 | /* the existing lease was read-only, so we can read too. */ | |
1211 | goto out; | |
1212 | } | |
1213 | ||
e32b8ee2 BF |
1214 | if (IS_ERR(new_fl) && !i_have_this_lease |
1215 | && ((mode & O_NONBLOCK) == 0)) { | |
1216 | error = PTR_ERR(new_fl); | |
1da177e4 LT |
1217 | goto out; |
1218 | } | |
1219 | ||
1220 | break_time = 0; | |
1221 | if (lease_break_time > 0) { | |
1222 | break_time = jiffies + lease_break_time * HZ; | |
1223 | if (break_time == 0) | |
1224 | break_time++; /* so that 0 means no break time */ | |
1225 | } | |
1226 | ||
1227 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { | |
1228 | if (fl->fl_type != future) { | |
1229 | fl->fl_type = future; | |
1230 | fl->fl_break_time = break_time; | |
1231 | /* lease must have lmops break callback */ | |
1232 | fl->fl_lmops->fl_break(fl); | |
1233 | } | |
1234 | } | |
1235 | ||
1236 | if (i_have_this_lease || (mode & O_NONBLOCK)) { | |
1237 | error = -EWOULDBLOCK; | |
1238 | goto out; | |
1239 | } | |
1240 | ||
1241 | restart: | |
1242 | break_time = flock->fl_break_time; | |
1243 | if (break_time != 0) { | |
1244 | break_time -= jiffies; | |
1245 | if (break_time == 0) | |
1246 | break_time++; | |
1247 | } | |
1248 | error = locks_block_on_timeout(flock, new_fl, break_time); | |
1249 | if (error >= 0) { | |
1250 | if (error == 0) | |
1251 | time_out_leases(inode); | |
1252 | /* Wait for the next lease that has not been broken yet */ | |
1253 | for (flock = inode->i_flock; flock && IS_LEASE(flock); | |
1254 | flock = flock->fl_next) { | |
1255 | if (flock->fl_type & F_INPROGRESS) | |
1256 | goto restart; | |
1257 | } | |
1258 | error = 0; | |
1259 | } | |
1260 | ||
1261 | out: | |
1262 | unlock_kernel(); | |
e32b8ee2 | 1263 | if (!IS_ERR(new_fl)) |
1da177e4 LT |
1264 | locks_free_lock(new_fl); |
1265 | return error; | |
1266 | } | |
1267 | ||
1268 | EXPORT_SYMBOL(__break_lease); | |
1269 | ||
1270 | /** | |
1271 | * lease_get_mtime | |
1272 | * @inode: the inode | |
1273 | * @time: pointer to a timespec which will contain the last modified time | |
1274 | * | |
1275 | * This is to force NFS clients to flush their caches for files with | |
1276 | * exclusive leases. The justification is that if someone has an | |
1277 | * exclusive lease, then they could be modifiying it. | |
1278 | */ | |
1279 | void lease_get_mtime(struct inode *inode, struct timespec *time) | |
1280 | { | |
1281 | struct file_lock *flock = inode->i_flock; | |
1282 | if (flock && IS_LEASE(flock) && (flock->fl_type & F_WRLCK)) | |
1283 | *time = current_fs_time(inode->i_sb); | |
1284 | else | |
1285 | *time = inode->i_mtime; | |
1286 | } | |
1287 | ||
1288 | EXPORT_SYMBOL(lease_get_mtime); | |
1289 | ||
1290 | /** | |
1291 | * fcntl_getlease - Enquire what lease is currently active | |
1292 | * @filp: the file | |
1293 | * | |
1294 | * The value returned by this function will be one of | |
1295 | * (if no lease break is pending): | |
1296 | * | |
1297 | * %F_RDLCK to indicate a shared lease is held. | |
1298 | * | |
1299 | * %F_WRLCK to indicate an exclusive lease is held. | |
1300 | * | |
1301 | * %F_UNLCK to indicate no lease is held. | |
1302 | * | |
1303 | * (if a lease break is pending): | |
1304 | * | |
1305 | * %F_RDLCK to indicate an exclusive lease needs to be | |
1306 | * changed to a shared lease (or removed). | |
1307 | * | |
1308 | * %F_UNLCK to indicate the lease needs to be removed. | |
1309 | * | |
1310 | * XXX: sfr & willy disagree over whether F_INPROGRESS | |
1311 | * should be returned to userspace. | |
1312 | */ | |
1313 | int fcntl_getlease(struct file *filp) | |
1314 | { | |
1315 | struct file_lock *fl; | |
1316 | int type = F_UNLCK; | |
1317 | ||
1318 | lock_kernel(); | |
0f7fc9e4 JJS |
1319 | time_out_leases(filp->f_path.dentry->d_inode); |
1320 | for (fl = filp->f_path.dentry->d_inode->i_flock; fl && IS_LEASE(fl); | |
1da177e4 LT |
1321 | fl = fl->fl_next) { |
1322 | if (fl->fl_file == filp) { | |
1323 | type = fl->fl_type & ~F_INPROGRESS; | |
1324 | break; | |
1325 | } | |
1326 | } | |
1327 | unlock_kernel(); | |
1328 | return type; | |
1329 | } | |
1330 | ||
1331 | /** | |
0af1a450 | 1332 | * generic_setlease - sets a lease on an open file |
1da177e4 LT |
1333 | * @filp: file pointer |
1334 | * @arg: type of lease to obtain | |
1335 | * @flp: input - file_lock to use, output - file_lock inserted | |
1336 | * | |
1337 | * The (input) flp->fl_lmops->fl_break function is required | |
1338 | * by break_lease(). | |
1339 | * | |
1340 | * Called with kernel lock held. | |
1341 | */ | |
0af1a450 | 1342 | int generic_setlease(struct file *filp, long arg, struct file_lock **flp) |
1da177e4 | 1343 | { |
7eaae282 | 1344 | struct file_lock *fl, **before, **my_before = NULL, *lease; |
85c59580 | 1345 | struct file_lock *new_fl = NULL; |
0f7fc9e4 | 1346 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 LT |
1347 | struct inode *inode = dentry->d_inode; |
1348 | int error, rdlease_count = 0, wrlease_count = 0; | |
1349 | ||
6d5e8b05 BF |
1350 | if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE)) |
1351 | return -EACCES; | |
1352 | if (!S_ISREG(inode->i_mode)) | |
1353 | return -EINVAL; | |
1354 | error = security_file_lock(filp, arg); | |
1355 | if (error) | |
1356 | return error; | |
1357 | ||
1da177e4 LT |
1358 | time_out_leases(inode); |
1359 | ||
d2ab0b0c | 1360 | BUG_ON(!(*flp)->fl_lmops->fl_break); |
1da177e4 | 1361 | |
7eaae282 KZ |
1362 | lease = *flp; |
1363 | ||
1da177e4 LT |
1364 | error = -EAGAIN; |
1365 | if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) | |
1366 | goto out; | |
1367 | if ((arg == F_WRLCK) | |
1368 | && ((atomic_read(&dentry->d_count) > 1) | |
1369 | || (atomic_read(&inode->i_count) > 1))) | |
1370 | goto out; | |
1371 | ||
85c59580 PE |
1372 | error = -ENOMEM; |
1373 | new_fl = locks_alloc_lock(); | |
1374 | if (new_fl == NULL) | |
1375 | goto out; | |
1376 | ||
1da177e4 LT |
1377 | /* |
1378 | * At this point, we know that if there is an exclusive | |
1379 | * lease on this file, then we hold it on this filp | |
1380 | * (otherwise our open of this file would have blocked). | |
1381 | * And if we are trying to acquire an exclusive lease, | |
1382 | * then the file is not open by anyone (including us) | |
1383 | * except for this filp. | |
1384 | */ | |
1385 | for (before = &inode->i_flock; | |
1386 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1387 | before = &fl->fl_next) { | |
1388 | if (lease->fl_lmops->fl_mylease(fl, lease)) | |
1389 | my_before = before; | |
1390 | else if (fl->fl_type == (F_INPROGRESS | F_UNLCK)) | |
1391 | /* | |
1392 | * Someone is in the process of opening this | |
1393 | * file for writing so we may not take an | |
1394 | * exclusive lease on it. | |
1395 | */ | |
1396 | wrlease_count++; | |
1397 | else | |
1398 | rdlease_count++; | |
1399 | } | |
1400 | ||
1401 | if ((arg == F_RDLCK && (wrlease_count > 0)) || | |
1402 | (arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0))) | |
1403 | goto out; | |
1404 | ||
1405 | if (my_before != NULL) { | |
75dff55a | 1406 | *flp = *my_before; |
1da177e4 LT |
1407 | error = lease->fl_lmops->fl_change(my_before, arg); |
1408 | goto out; | |
1409 | } | |
1410 | ||
1411 | error = 0; | |
1412 | if (arg == F_UNLCK) | |
1413 | goto out; | |
1414 | ||
1415 | error = -EINVAL; | |
1416 | if (!leases_enable) | |
1417 | goto out; | |
1418 | ||
85c59580 PE |
1419 | locks_copy_lock(new_fl, lease); |
1420 | locks_insert_lock(before, new_fl); | |
1da177e4 | 1421 | |
85c59580 PE |
1422 | *flp = new_fl; |
1423 | return 0; | |
1da177e4 | 1424 | |
1da177e4 | 1425 | out: |
85c59580 PE |
1426 | if (new_fl != NULL) |
1427 | locks_free_lock(new_fl); | |
1da177e4 LT |
1428 | return error; |
1429 | } | |
0af1a450 | 1430 | EXPORT_SYMBOL(generic_setlease); |
1da177e4 LT |
1431 | |
1432 | /** | |
a9933cea | 1433 | * vfs_setlease - sets a lease on an open file |
1da177e4 LT |
1434 | * @filp: file pointer |
1435 | * @arg: type of lease to obtain | |
1436 | * @lease: file_lock to use | |
1437 | * | |
1438 | * Call this to establish a lease on the file. | |
f9ffed26 BF |
1439 | * The (*lease)->fl_lmops->fl_break operation must be set; if not, |
1440 | * break_lease will oops! | |
1441 | * | |
1442 | * This will call the filesystem's setlease file method, if | |
1443 | * defined. Note that there is no getlease method; instead, the | |
1444 | * filesystem setlease method should call back to setlease() to | |
1445 | * add a lease to the inode's lease list, where fcntl_getlease() can | |
1446 | * find it. Since fcntl_getlease() only reports whether the current | |
1447 | * task holds a lease, a cluster filesystem need only do this for | |
1448 | * leases held by processes on this node. | |
1449 | * | |
1450 | * There is also no break_lease method; filesystems that | |
1451 | * handle their own leases shoud break leases themselves from the | |
1452 | * filesystem's open, create, and (on truncate) setattr methods. | |
1453 | * | |
1454 | * Warning: the only current setlease methods exist only to disable | |
1455 | * leases in certain cases. More vfs changes may be required to | |
1456 | * allow a full filesystem lease implementation. | |
1da177e4 LT |
1457 | */ |
1458 | ||
a9933cea | 1459 | int vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1da177e4 | 1460 | { |
1da177e4 LT |
1461 | int error; |
1462 | ||
1da177e4 | 1463 | lock_kernel(); |
f9ffed26 BF |
1464 | if (filp->f_op && filp->f_op->setlease) |
1465 | error = filp->f_op->setlease(filp, arg, lease); | |
1466 | else | |
0af1a450 | 1467 | error = generic_setlease(filp, arg, lease); |
1da177e4 LT |
1468 | unlock_kernel(); |
1469 | ||
1470 | return error; | |
1471 | } | |
a9933cea | 1472 | EXPORT_SYMBOL_GPL(vfs_setlease); |
1da177e4 LT |
1473 | |
1474 | /** | |
1475 | * fcntl_setlease - sets a lease on an open file | |
1476 | * @fd: open file descriptor | |
1477 | * @filp: file pointer | |
1478 | * @arg: type of lease to obtain | |
1479 | * | |
1480 | * Call this fcntl to establish a lease on the file. | |
1481 | * Note that you also need to call %F_SETSIG to | |
1482 | * receive a signal when the lease is broken. | |
1483 | */ | |
1484 | int fcntl_setlease(unsigned int fd, struct file *filp, long arg) | |
1485 | { | |
1486 | struct file_lock fl, *flp = &fl; | |
0f7fc9e4 | 1487 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 LT |
1488 | struct inode *inode = dentry->d_inode; |
1489 | int error; | |
1490 | ||
1da177e4 LT |
1491 | locks_init_lock(&fl); |
1492 | error = lease_init(filp, arg, &fl); | |
1493 | if (error) | |
1494 | return error; | |
1495 | ||
1496 | lock_kernel(); | |
1497 | ||
a9933cea | 1498 | error = vfs_setlease(filp, arg, &flp); |
dc15ae14 | 1499 | if (error || arg == F_UNLCK) |
1da177e4 LT |
1500 | goto out_unlock; |
1501 | ||
1502 | error = fasync_helper(fd, filp, 1, &flp->fl_fasync); | |
1503 | if (error < 0) { | |
6d5e8b05 | 1504 | /* remove lease just inserted by setlease */ |
1da177e4 | 1505 | flp->fl_type = F_UNLCK | F_INPROGRESS; |
6d5e8b05 | 1506 | flp->fl_break_time = jiffies - 10; |
1da177e4 LT |
1507 | time_out_leases(inode); |
1508 | goto out_unlock; | |
1509 | } | |
1510 | ||
609d7fa9 | 1511 | error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); |
1da177e4 LT |
1512 | out_unlock: |
1513 | unlock_kernel(); | |
1514 | return error; | |
1515 | } | |
1516 | ||
1517 | /** | |
1518 | * flock_lock_file_wait - Apply a FLOCK-style lock to a file | |
1519 | * @filp: The file to apply the lock to | |
1520 | * @fl: The lock to be applied | |
1521 | * | |
1522 | * Add a FLOCK style lock to a file. | |
1523 | */ | |
1524 | int flock_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1525 | { | |
1526 | int error; | |
1527 | might_sleep(); | |
1528 | for (;;) { | |
1529 | error = flock_lock_file(filp, fl); | |
1530 | if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP)) | |
1531 | break; | |
1532 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1533 | if (!error) | |
1534 | continue; | |
1535 | ||
1536 | locks_delete_block(fl); | |
1537 | break; | |
1538 | } | |
1539 | return error; | |
1540 | } | |
1541 | ||
1542 | EXPORT_SYMBOL(flock_lock_file_wait); | |
1543 | ||
1544 | /** | |
1545 | * sys_flock: - flock() system call. | |
1546 | * @fd: the file descriptor to lock. | |
1547 | * @cmd: the type of lock to apply. | |
1548 | * | |
1549 | * Apply a %FL_FLOCK style lock to an open file descriptor. | |
1550 | * The @cmd can be one of | |
1551 | * | |
1552 | * %LOCK_SH -- a shared lock. | |
1553 | * | |
1554 | * %LOCK_EX -- an exclusive lock. | |
1555 | * | |
1556 | * %LOCK_UN -- remove an existing lock. | |
1557 | * | |
1558 | * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes. | |
1559 | * | |
1560 | * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other | |
1561 | * processes read and write access respectively. | |
1562 | */ | |
1563 | asmlinkage long sys_flock(unsigned int fd, unsigned int cmd) | |
1564 | { | |
1565 | struct file *filp; | |
1566 | struct file_lock *lock; | |
1567 | int can_sleep, unlock; | |
1568 | int error; | |
1569 | ||
1570 | error = -EBADF; | |
1571 | filp = fget(fd); | |
1572 | if (!filp) | |
1573 | goto out; | |
1574 | ||
1575 | can_sleep = !(cmd & LOCK_NB); | |
1576 | cmd &= ~LOCK_NB; | |
1577 | unlock = (cmd == LOCK_UN); | |
1578 | ||
1579 | if (!unlock && !(cmd & LOCK_MAND) && !(filp->f_mode & 3)) | |
1580 | goto out_putf; | |
1581 | ||
1582 | error = flock_make_lock(filp, &lock, cmd); | |
1583 | if (error) | |
1584 | goto out_putf; | |
1585 | if (can_sleep) | |
1586 | lock->fl_flags |= FL_SLEEP; | |
1587 | ||
1588 | error = security_file_lock(filp, cmd); | |
1589 | if (error) | |
1590 | goto out_free; | |
1591 | ||
1592 | if (filp->f_op && filp->f_op->flock) | |
1593 | error = filp->f_op->flock(filp, | |
1594 | (can_sleep) ? F_SETLKW : F_SETLK, | |
1595 | lock); | |
1596 | else | |
1597 | error = flock_lock_file_wait(filp, lock); | |
1598 | ||
1599 | out_free: | |
993dfa87 | 1600 | locks_free_lock(lock); |
1da177e4 LT |
1601 | |
1602 | out_putf: | |
1603 | fput(filp); | |
1604 | out: | |
1605 | return error; | |
1606 | } | |
1607 | ||
3ee17abd BF |
1608 | /** |
1609 | * vfs_test_lock - test file byte range lock | |
1610 | * @filp: The file to test lock for | |
6924c554 | 1611 | * @fl: The lock to test; also used to hold result |
3ee17abd BF |
1612 | * |
1613 | * Returns -ERRNO on failure. Indicates presence of conflicting lock by | |
1614 | * setting conf->fl_type to something other than F_UNLCK. | |
1615 | */ | |
1616 | int vfs_test_lock(struct file *filp, struct file_lock *fl) | |
1617 | { | |
1618 | if (filp->f_op && filp->f_op->lock) | |
1619 | return filp->f_op->lock(filp, F_GETLK, fl); | |
1620 | posix_test_lock(filp, fl); | |
1621 | return 0; | |
1622 | } | |
1623 | EXPORT_SYMBOL_GPL(vfs_test_lock); | |
1624 | ||
c2fa1b8a BF |
1625 | static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) |
1626 | { | |
1627 | flock->l_pid = fl->fl_pid; | |
1628 | #if BITS_PER_LONG == 32 | |
1629 | /* | |
1630 | * Make sure we can represent the posix lock via | |
1631 | * legacy 32bit flock. | |
1632 | */ | |
1633 | if (fl->fl_start > OFFT_OFFSET_MAX) | |
1634 | return -EOVERFLOW; | |
1635 | if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX) | |
1636 | return -EOVERFLOW; | |
1637 | #endif | |
1638 | flock->l_start = fl->fl_start; | |
1639 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1640 | fl->fl_end - fl->fl_start + 1; | |
1641 | flock->l_whence = 0; | |
129a84de | 1642 | flock->l_type = fl->fl_type; |
c2fa1b8a BF |
1643 | return 0; |
1644 | } | |
1645 | ||
1646 | #if BITS_PER_LONG == 32 | |
1647 | static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) | |
1648 | { | |
1649 | flock->l_pid = fl->fl_pid; | |
1650 | flock->l_start = fl->fl_start; | |
1651 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1652 | fl->fl_end - fl->fl_start + 1; | |
1653 | flock->l_whence = 0; | |
1654 | flock->l_type = fl->fl_type; | |
1655 | } | |
1656 | #endif | |
1657 | ||
1da177e4 LT |
1658 | /* Report the first existing lock that would conflict with l. |
1659 | * This implements the F_GETLK command of fcntl(). | |
1660 | */ | |
1661 | int fcntl_getlk(struct file *filp, struct flock __user *l) | |
1662 | { | |
9d6a8c5c | 1663 | struct file_lock file_lock; |
1da177e4 LT |
1664 | struct flock flock; |
1665 | int error; | |
1666 | ||
1667 | error = -EFAULT; | |
1668 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1669 | goto out; | |
1670 | error = -EINVAL; | |
1671 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
1672 | goto out; | |
1673 | ||
1674 | error = flock_to_posix_lock(filp, &file_lock, &flock); | |
1675 | if (error) | |
1676 | goto out; | |
1677 | ||
3ee17abd BF |
1678 | error = vfs_test_lock(filp, &file_lock); |
1679 | if (error) | |
1680 | goto out; | |
1da177e4 | 1681 | |
9d6a8c5c ME |
1682 | flock.l_type = file_lock.fl_type; |
1683 | if (file_lock.fl_type != F_UNLCK) { | |
1684 | error = posix_lock_to_flock(&flock, &file_lock); | |
c2fa1b8a | 1685 | if (error) |
1da177e4 | 1686 | goto out; |
1da177e4 LT |
1687 | } |
1688 | error = -EFAULT; | |
1689 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
1690 | error = 0; | |
1691 | out: | |
1692 | return error; | |
1693 | } | |
1694 | ||
7723ec97 ME |
1695 | /** |
1696 | * vfs_lock_file - file byte range lock | |
1697 | * @filp: The file to apply the lock to | |
1698 | * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.) | |
1699 | * @fl: The lock to be applied | |
150b3934 ME |
1700 | * @conf: Place to return a copy of the conflicting lock, if found. |
1701 | * | |
1702 | * A caller that doesn't care about the conflicting lock may pass NULL | |
1703 | * as the final argument. | |
1704 | * | |
1705 | * If the filesystem defines a private ->lock() method, then @conf will | |
1706 | * be left unchanged; so a caller that cares should initialize it to | |
1707 | * some acceptable default. | |
2beb6614 ME |
1708 | * |
1709 | * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX | |
1710 | * locks, the ->lock() interface may return asynchronously, before the lock has | |
1711 | * been granted or denied by the underlying filesystem, if (and only if) | |
1712 | * fl_grant is set. Callers expecting ->lock() to return asynchronously | |
1713 | * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if) | |
1714 | * the request is for a blocking lock. When ->lock() does return asynchronously, | |
1715 | * it must return -EINPROGRESS, and call ->fl_grant() when the lock | |
1716 | * request completes. | |
1717 | * If the request is for non-blocking lock the file system should return | |
1718 | * -EINPROGRESS then try to get the lock and call the callback routine with | |
1719 | * the result. If the request timed out the callback routine will return a | |
1720 | * nonzero return code and the file system should release the lock. The file | |
1721 | * system is also responsible to keep a corresponding posix lock when it | |
1722 | * grants a lock so the VFS can find out which locks are locally held and do | |
1723 | * the correct lock cleanup when required. | |
1724 | * The underlying filesystem must not drop the kernel lock or call | |
1725 | * ->fl_grant() before returning to the caller with a -EINPROGRESS | |
1726 | * return code. | |
7723ec97 | 1727 | */ |
150b3934 | 1728 | int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf) |
7723ec97 ME |
1729 | { |
1730 | if (filp->f_op && filp->f_op->lock) | |
1731 | return filp->f_op->lock(filp, cmd, fl); | |
1732 | else | |
150b3934 | 1733 | return posix_lock_file(filp, fl, conf); |
7723ec97 ME |
1734 | } |
1735 | EXPORT_SYMBOL_GPL(vfs_lock_file); | |
1736 | ||
1da177e4 LT |
1737 | /* Apply the lock described by l to an open file descriptor. |
1738 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
1739 | */ | |
c293621b PS |
1740 | int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, |
1741 | struct flock __user *l) | |
1da177e4 LT |
1742 | { |
1743 | struct file_lock *file_lock = locks_alloc_lock(); | |
1744 | struct flock flock; | |
1745 | struct inode *inode; | |
1746 | int error; | |
1747 | ||
1748 | if (file_lock == NULL) | |
1749 | return -ENOLCK; | |
1750 | ||
1751 | /* | |
1752 | * This might block, so we do it before checking the inode. | |
1753 | */ | |
1754 | error = -EFAULT; | |
1755 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1756 | goto out; | |
1757 | ||
0f7fc9e4 | 1758 | inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1759 | |
1760 | /* Don't allow mandatory locks on files that may be memory mapped | |
1761 | * and shared. | |
1762 | */ | |
a16877ca | 1763 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
1764 | error = -EAGAIN; |
1765 | goto out; | |
1766 | } | |
1767 | ||
c293621b | 1768 | again: |
1da177e4 LT |
1769 | error = flock_to_posix_lock(filp, file_lock, &flock); |
1770 | if (error) | |
1771 | goto out; | |
1772 | if (cmd == F_SETLKW) { | |
1773 | file_lock->fl_flags |= FL_SLEEP; | |
1774 | } | |
1775 | ||
1776 | error = -EBADF; | |
1777 | switch (flock.l_type) { | |
1778 | case F_RDLCK: | |
1779 | if (!(filp->f_mode & FMODE_READ)) | |
1780 | goto out; | |
1781 | break; | |
1782 | case F_WRLCK: | |
1783 | if (!(filp->f_mode & FMODE_WRITE)) | |
1784 | goto out; | |
1785 | break; | |
1786 | case F_UNLCK: | |
1787 | break; | |
1788 | default: | |
1789 | error = -EINVAL; | |
1790 | goto out; | |
1791 | } | |
1792 | ||
1793 | error = security_file_lock(filp, file_lock->fl_type); | |
1794 | if (error) | |
1795 | goto out; | |
1796 | ||
7723ec97 | 1797 | for (;;) { |
150b3934 | 1798 | error = vfs_lock_file(filp, cmd, file_lock, NULL); |
7723ec97 | 1799 | if (error != -EAGAIN || cmd == F_SETLK) |
1da177e4 | 1800 | break; |
7723ec97 ME |
1801 | error = wait_event_interruptible(file_lock->fl_wait, |
1802 | !file_lock->fl_next); | |
1803 | if (!error) | |
1804 | continue; | |
1805 | ||
1806 | locks_delete_block(file_lock); | |
1807 | break; | |
c293621b | 1808 | } |
1da177e4 | 1809 | |
c293621b PS |
1810 | /* |
1811 | * Attempt to detect a close/fcntl race and recover by | |
1812 | * releasing the lock that was just acquired. | |
1813 | */ | |
1814 | if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) { | |
1815 | flock.l_type = F_UNLCK; | |
1816 | goto again; | |
1da177e4 LT |
1817 | } |
1818 | ||
c293621b | 1819 | out: |
1da177e4 LT |
1820 | locks_free_lock(file_lock); |
1821 | return error; | |
1822 | } | |
1823 | ||
1824 | #if BITS_PER_LONG == 32 | |
1825 | /* Report the first existing lock that would conflict with l. | |
1826 | * This implements the F_GETLK command of fcntl(). | |
1827 | */ | |
1828 | int fcntl_getlk64(struct file *filp, struct flock64 __user *l) | |
1829 | { | |
9d6a8c5c | 1830 | struct file_lock file_lock; |
1da177e4 LT |
1831 | struct flock64 flock; |
1832 | int error; | |
1833 | ||
1834 | error = -EFAULT; | |
1835 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1836 | goto out; | |
1837 | error = -EINVAL; | |
1838 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
1839 | goto out; | |
1840 | ||
1841 | error = flock64_to_posix_lock(filp, &file_lock, &flock); | |
1842 | if (error) | |
1843 | goto out; | |
1844 | ||
3ee17abd BF |
1845 | error = vfs_test_lock(filp, &file_lock); |
1846 | if (error) | |
1847 | goto out; | |
1848 | ||
9d6a8c5c ME |
1849 | flock.l_type = file_lock.fl_type; |
1850 | if (file_lock.fl_type != F_UNLCK) | |
1851 | posix_lock_to_flock64(&flock, &file_lock); | |
1852 | ||
1da177e4 LT |
1853 | error = -EFAULT; |
1854 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
1855 | error = 0; | |
1856 | ||
1857 | out: | |
1858 | return error; | |
1859 | } | |
1860 | ||
1861 | /* Apply the lock described by l to an open file descriptor. | |
1862 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
1863 | */ | |
c293621b PS |
1864 | int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, |
1865 | struct flock64 __user *l) | |
1da177e4 LT |
1866 | { |
1867 | struct file_lock *file_lock = locks_alloc_lock(); | |
1868 | struct flock64 flock; | |
1869 | struct inode *inode; | |
1870 | int error; | |
1871 | ||
1872 | if (file_lock == NULL) | |
1873 | return -ENOLCK; | |
1874 | ||
1875 | /* | |
1876 | * This might block, so we do it before checking the inode. | |
1877 | */ | |
1878 | error = -EFAULT; | |
1879 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1880 | goto out; | |
1881 | ||
0f7fc9e4 | 1882 | inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1883 | |
1884 | /* Don't allow mandatory locks on files that may be memory mapped | |
1885 | * and shared. | |
1886 | */ | |
a16877ca | 1887 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
1888 | error = -EAGAIN; |
1889 | goto out; | |
1890 | } | |
1891 | ||
c293621b | 1892 | again: |
1da177e4 LT |
1893 | error = flock64_to_posix_lock(filp, file_lock, &flock); |
1894 | if (error) | |
1895 | goto out; | |
1896 | if (cmd == F_SETLKW64) { | |
1897 | file_lock->fl_flags |= FL_SLEEP; | |
1898 | } | |
1899 | ||
1900 | error = -EBADF; | |
1901 | switch (flock.l_type) { | |
1902 | case F_RDLCK: | |
1903 | if (!(filp->f_mode & FMODE_READ)) | |
1904 | goto out; | |
1905 | break; | |
1906 | case F_WRLCK: | |
1907 | if (!(filp->f_mode & FMODE_WRITE)) | |
1908 | goto out; | |
1909 | break; | |
1910 | case F_UNLCK: | |
1911 | break; | |
1912 | default: | |
1913 | error = -EINVAL; | |
1914 | goto out; | |
1915 | } | |
1916 | ||
1917 | error = security_file_lock(filp, file_lock->fl_type); | |
1918 | if (error) | |
1919 | goto out; | |
1920 | ||
7723ec97 | 1921 | for (;;) { |
150b3934 | 1922 | error = vfs_lock_file(filp, cmd, file_lock, NULL); |
7723ec97 | 1923 | if (error != -EAGAIN || cmd == F_SETLK64) |
1da177e4 | 1924 | break; |
7723ec97 ME |
1925 | error = wait_event_interruptible(file_lock->fl_wait, |
1926 | !file_lock->fl_next); | |
1927 | if (!error) | |
1928 | continue; | |
1929 | ||
1930 | locks_delete_block(file_lock); | |
1931 | break; | |
c293621b | 1932 | } |
1da177e4 | 1933 | |
c293621b PS |
1934 | /* |
1935 | * Attempt to detect a close/fcntl race and recover by | |
1936 | * releasing the lock that was just acquired. | |
1937 | */ | |
1938 | if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) { | |
1939 | flock.l_type = F_UNLCK; | |
1940 | goto again; | |
1da177e4 LT |
1941 | } |
1942 | ||
1943 | out: | |
1944 | locks_free_lock(file_lock); | |
1945 | return error; | |
1946 | } | |
1947 | #endif /* BITS_PER_LONG == 32 */ | |
1948 | ||
1949 | /* | |
1950 | * This function is called when the file is being removed | |
1951 | * from the task's fd array. POSIX locks belonging to this task | |
1952 | * are deleted at this time. | |
1953 | */ | |
1954 | void locks_remove_posix(struct file *filp, fl_owner_t owner) | |
1955 | { | |
ff7b86b8 | 1956 | struct file_lock lock; |
1da177e4 LT |
1957 | |
1958 | /* | |
1959 | * If there are no locks held on this file, we don't need to call | |
1960 | * posix_lock_file(). Another process could be setting a lock on this | |
1961 | * file at the same time, but we wouldn't remove that lock anyway. | |
1962 | */ | |
0f7fc9e4 | 1963 | if (!filp->f_path.dentry->d_inode->i_flock) |
1da177e4 LT |
1964 | return; |
1965 | ||
1966 | lock.fl_type = F_UNLCK; | |
75e1fcc0 | 1967 | lock.fl_flags = FL_POSIX | FL_CLOSE; |
1da177e4 LT |
1968 | lock.fl_start = 0; |
1969 | lock.fl_end = OFFSET_MAX; | |
1970 | lock.fl_owner = owner; | |
1971 | lock.fl_pid = current->tgid; | |
1972 | lock.fl_file = filp; | |
1973 | lock.fl_ops = NULL; | |
1974 | lock.fl_lmops = NULL; | |
1975 | ||
150b3934 | 1976 | vfs_lock_file(filp, F_SETLK, &lock, NULL); |
1da177e4 | 1977 | |
1da177e4 LT |
1978 | if (lock.fl_ops && lock.fl_ops->fl_release_private) |
1979 | lock.fl_ops->fl_release_private(&lock); | |
1980 | } | |
1981 | ||
1982 | EXPORT_SYMBOL(locks_remove_posix); | |
1983 | ||
1984 | /* | |
1985 | * This function is called on the last close of an open file. | |
1986 | */ | |
1987 | void locks_remove_flock(struct file *filp) | |
1988 | { | |
0f7fc9e4 | 1989 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1990 | struct file_lock *fl; |
1991 | struct file_lock **before; | |
1992 | ||
1993 | if (!inode->i_flock) | |
1994 | return; | |
1995 | ||
1996 | if (filp->f_op && filp->f_op->flock) { | |
1997 | struct file_lock fl = { | |
1998 | .fl_pid = current->tgid, | |
1999 | .fl_file = filp, | |
2000 | .fl_flags = FL_FLOCK, | |
2001 | .fl_type = F_UNLCK, | |
2002 | .fl_end = OFFSET_MAX, | |
2003 | }; | |
2004 | filp->f_op->flock(filp, F_SETLKW, &fl); | |
80fec4c6 TM |
2005 | if (fl.fl_ops && fl.fl_ops->fl_release_private) |
2006 | fl.fl_ops->fl_release_private(&fl); | |
1da177e4 LT |
2007 | } |
2008 | ||
2009 | lock_kernel(); | |
2010 | before = &inode->i_flock; | |
2011 | ||
2012 | while ((fl = *before) != NULL) { | |
2013 | if (fl->fl_file == filp) { | |
c293621b | 2014 | if (IS_FLOCK(fl)) { |
1da177e4 LT |
2015 | locks_delete_lock(before); |
2016 | continue; | |
2017 | } | |
2018 | if (IS_LEASE(fl)) { | |
2019 | lease_modify(before, F_UNLCK); | |
2020 | continue; | |
2021 | } | |
2022 | /* What? */ | |
2023 | BUG(); | |
2024 | } | |
2025 | before = &fl->fl_next; | |
2026 | } | |
2027 | unlock_kernel(); | |
2028 | } | |
2029 | ||
1da177e4 LT |
2030 | /** |
2031 | * posix_unblock_lock - stop waiting for a file lock | |
2032 | * @filp: how the file was opened | |
2033 | * @waiter: the lock which was waiting | |
2034 | * | |
2035 | * lockd needs to block waiting for locks. | |
2036 | */ | |
64a318ee | 2037 | int |
1da177e4 LT |
2038 | posix_unblock_lock(struct file *filp, struct file_lock *waiter) |
2039 | { | |
64a318ee BF |
2040 | int status = 0; |
2041 | ||
1da177e4 | 2042 | lock_kernel(); |
5996a298 | 2043 | if (waiter->fl_next) |
1da177e4 | 2044 | __locks_delete_block(waiter); |
64a318ee BF |
2045 | else |
2046 | status = -ENOENT; | |
5996a298 | 2047 | unlock_kernel(); |
64a318ee | 2048 | return status; |
1da177e4 LT |
2049 | } |
2050 | ||
2051 | EXPORT_SYMBOL(posix_unblock_lock); | |
2052 | ||
9b9d2ab4 ME |
2053 | /** |
2054 | * vfs_cancel_lock - file byte range unblock lock | |
2055 | * @filp: The file to apply the unblock to | |
2056 | * @fl: The lock to be unblocked | |
2057 | * | |
2058 | * Used by lock managers to cancel blocked requests | |
2059 | */ | |
2060 | int vfs_cancel_lock(struct file *filp, struct file_lock *fl) | |
2061 | { | |
2062 | if (filp->f_op && filp->f_op->lock) | |
2063 | return filp->f_op->lock(filp, F_CANCELLK, fl); | |
2064 | return 0; | |
2065 | } | |
2066 | ||
2067 | EXPORT_SYMBOL_GPL(vfs_cancel_lock); | |
2068 | ||
7f8ada98 PE |
2069 | #ifdef CONFIG_PROC_FS |
2070 | #include <linux/seq_file.h> | |
2071 | ||
2072 | static void lock_get_status(struct seq_file *f, struct file_lock *fl, | |
2073 | int id, char *pfx) | |
1da177e4 LT |
2074 | { |
2075 | struct inode *inode = NULL; | |
2076 | ||
2077 | if (fl->fl_file != NULL) | |
0f7fc9e4 | 2078 | inode = fl->fl_file->f_path.dentry->d_inode; |
1da177e4 | 2079 | |
7f8ada98 | 2080 | seq_printf(f, "%d:%s ", id, pfx); |
1da177e4 | 2081 | if (IS_POSIX(fl)) { |
7f8ada98 | 2082 | seq_printf(f, "%6s %s ", |
1da177e4 LT |
2083 | (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ", |
2084 | (inode == NULL) ? "*NOINODE*" : | |
a16877ca | 2085 | mandatory_lock(inode) ? "MANDATORY" : "ADVISORY "); |
1da177e4 LT |
2086 | } else if (IS_FLOCK(fl)) { |
2087 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2088 | seq_printf(f, "FLOCK MSNFS "); |
1da177e4 | 2089 | } else { |
7f8ada98 | 2090 | seq_printf(f, "FLOCK ADVISORY "); |
1da177e4 LT |
2091 | } |
2092 | } else if (IS_LEASE(fl)) { | |
7f8ada98 | 2093 | seq_printf(f, "LEASE "); |
1da177e4 | 2094 | if (fl->fl_type & F_INPROGRESS) |
7f8ada98 | 2095 | seq_printf(f, "BREAKING "); |
1da177e4 | 2096 | else if (fl->fl_file) |
7f8ada98 | 2097 | seq_printf(f, "ACTIVE "); |
1da177e4 | 2098 | else |
7f8ada98 | 2099 | seq_printf(f, "BREAKER "); |
1da177e4 | 2100 | } else { |
7f8ada98 | 2101 | seq_printf(f, "UNKNOWN UNKNOWN "); |
1da177e4 LT |
2102 | } |
2103 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2104 | seq_printf(f, "%s ", |
1da177e4 LT |
2105 | (fl->fl_type & LOCK_READ) |
2106 | ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ " | |
2107 | : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE "); | |
2108 | } else { | |
7f8ada98 | 2109 | seq_printf(f, "%s ", |
1da177e4 LT |
2110 | (fl->fl_type & F_INPROGRESS) |
2111 | ? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ " | |
2112 | : (fl->fl_type & F_WRLCK) ? "WRITE" : "READ "); | |
2113 | } | |
2114 | if (inode) { | |
2115 | #ifdef WE_CAN_BREAK_LSLK_NOW | |
7f8ada98 | 2116 | seq_printf(f, "%d %s:%ld ", fl->fl_pid, |
1da177e4 LT |
2117 | inode->i_sb->s_id, inode->i_ino); |
2118 | #else | |
2119 | /* userspace relies on this representation of dev_t ;-( */ | |
7f8ada98 | 2120 | seq_printf(f, "%d %02x:%02x:%ld ", fl->fl_pid, |
1da177e4 LT |
2121 | MAJOR(inode->i_sb->s_dev), |
2122 | MINOR(inode->i_sb->s_dev), inode->i_ino); | |
2123 | #endif | |
2124 | } else { | |
7f8ada98 | 2125 | seq_printf(f, "%d <none>:0 ", fl->fl_pid); |
1da177e4 LT |
2126 | } |
2127 | if (IS_POSIX(fl)) { | |
2128 | if (fl->fl_end == OFFSET_MAX) | |
7f8ada98 | 2129 | seq_printf(f, "%Ld EOF\n", fl->fl_start); |
1da177e4 | 2130 | else |
7f8ada98 | 2131 | seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end); |
1da177e4 | 2132 | } else { |
7f8ada98 | 2133 | seq_printf(f, "0 EOF\n"); |
1da177e4 LT |
2134 | } |
2135 | } | |
2136 | ||
7f8ada98 | 2137 | static int locks_show(struct seq_file *f, void *v) |
1da177e4 | 2138 | { |
7f8ada98 | 2139 | struct file_lock *fl, *bfl; |
1da177e4 | 2140 | |
7f8ada98 | 2141 | fl = list_entry(v, struct file_lock, fl_link); |
1da177e4 | 2142 | |
7f8ada98 | 2143 | lock_get_status(f, fl, (long)f->private, ""); |
1da177e4 | 2144 | |
7f8ada98 PE |
2145 | list_for_each_entry(bfl, &fl->fl_block, fl_block) |
2146 | lock_get_status(f, bfl, (long)f->private, " ->"); | |
094f2825 | 2147 | |
7f8ada98 PE |
2148 | f->private++; |
2149 | return 0; | |
2150 | } | |
1da177e4 | 2151 | |
7f8ada98 PE |
2152 | static void *locks_start(struct seq_file *f, loff_t *pos) |
2153 | { | |
2154 | lock_kernel(); | |
2155 | f->private = (void *)1; | |
2156 | return seq_list_start(&file_lock_list, *pos); | |
2157 | } | |
1da177e4 | 2158 | |
7f8ada98 PE |
2159 | static void *locks_next(struct seq_file *f, void *v, loff_t *pos) |
2160 | { | |
2161 | return seq_list_next(v, &file_lock_list, pos); | |
2162 | } | |
1da177e4 | 2163 | |
7f8ada98 PE |
2164 | static void locks_stop(struct seq_file *f, void *v) |
2165 | { | |
1da177e4 | 2166 | unlock_kernel(); |
1da177e4 LT |
2167 | } |
2168 | ||
7f8ada98 PE |
2169 | struct seq_operations locks_seq_operations = { |
2170 | .start = locks_start, | |
2171 | .next = locks_next, | |
2172 | .stop = locks_stop, | |
2173 | .show = locks_show, | |
2174 | }; | |
2175 | #endif | |
2176 | ||
1da177e4 LT |
2177 | /** |
2178 | * lock_may_read - checks that the region is free of locks | |
2179 | * @inode: the inode that is being read | |
2180 | * @start: the first byte to read | |
2181 | * @len: the number of bytes to read | |
2182 | * | |
2183 | * Emulates Windows locking requirements. Whole-file | |
2184 | * mandatory locks (share modes) can prohibit a read and | |
2185 | * byte-range POSIX locks can prohibit a read if they overlap. | |
2186 | * | |
2187 | * N.B. this function is only ever called | |
2188 | * from knfsd and ownership of locks is never checked. | |
2189 | */ | |
2190 | int lock_may_read(struct inode *inode, loff_t start, unsigned long len) | |
2191 | { | |
2192 | struct file_lock *fl; | |
2193 | int result = 1; | |
2194 | lock_kernel(); | |
2195 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { | |
2196 | if (IS_POSIX(fl)) { | |
2197 | if (fl->fl_type == F_RDLCK) | |
2198 | continue; | |
2199 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2200 | continue; | |
2201 | } else if (IS_FLOCK(fl)) { | |
2202 | if (!(fl->fl_type & LOCK_MAND)) | |
2203 | continue; | |
2204 | if (fl->fl_type & LOCK_READ) | |
2205 | continue; | |
2206 | } else | |
2207 | continue; | |
2208 | result = 0; | |
2209 | break; | |
2210 | } | |
2211 | unlock_kernel(); | |
2212 | return result; | |
2213 | } | |
2214 | ||
2215 | EXPORT_SYMBOL(lock_may_read); | |
2216 | ||
2217 | /** | |
2218 | * lock_may_write - checks that the region is free of locks | |
2219 | * @inode: the inode that is being written | |
2220 | * @start: the first byte to write | |
2221 | * @len: the number of bytes to write | |
2222 | * | |
2223 | * Emulates Windows locking requirements. Whole-file | |
2224 | * mandatory locks (share modes) can prohibit a write and | |
2225 | * byte-range POSIX locks can prohibit a write if they overlap. | |
2226 | * | |
2227 | * N.B. this function is only ever called | |
2228 | * from knfsd and ownership of locks is never checked. | |
2229 | */ | |
2230 | int lock_may_write(struct inode *inode, loff_t start, unsigned long len) | |
2231 | { | |
2232 | struct file_lock *fl; | |
2233 | int result = 1; | |
2234 | lock_kernel(); | |
2235 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { | |
2236 | if (IS_POSIX(fl)) { | |
2237 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2238 | continue; | |
2239 | } else if (IS_FLOCK(fl)) { | |
2240 | if (!(fl->fl_type & LOCK_MAND)) | |
2241 | continue; | |
2242 | if (fl->fl_type & LOCK_WRITE) | |
2243 | continue; | |
2244 | } else | |
2245 | continue; | |
2246 | result = 0; | |
2247 | break; | |
2248 | } | |
2249 | unlock_kernel(); | |
2250 | return result; | |
2251 | } | |
2252 | ||
2253 | EXPORT_SYMBOL(lock_may_write); | |
2254 | ||
1da177e4 LT |
2255 | static int __init filelock_init(void) |
2256 | { | |
2257 | filelock_cache = kmem_cache_create("file_lock_cache", | |
2258 | sizeof(struct file_lock), 0, SLAB_PANIC, | |
20c2df83 | 2259 | init_once); |
1da177e4 LT |
2260 | return 0; |
2261 | } | |
2262 | ||
2263 | core_initcall(filelock_init); |