Commit | Line | Data |
---|---|---|
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. | |
395cf969 | 63 | * See 'Documentation/filesystems/mandatory-locking.txt' for details. |
1da177e4 LT |
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> | |
9f3acc31 | 119 | #include <linux/fdtable.h> |
1da177e4 LT |
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> | |
1da177e4 LT |
125 | #include <linux/syscalls.h> |
126 | #include <linux/time.h> | |
4fb3a538 | 127 | #include <linux/rcupdate.h> |
ab1f1611 | 128 | #include <linux/pid_namespace.h> |
1da177e4 | 129 | |
1da177e4 LT |
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 | ||
ab83fa4b BF |
136 | static bool lease_breaking(struct file_lock *fl) |
137 | { | |
778fc546 BF |
138 | return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING); |
139 | } | |
140 | ||
141 | static int target_leasetype(struct file_lock *fl) | |
142 | { | |
143 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
144 | return F_UNLCK; | |
145 | if (fl->fl_flags & FL_DOWNGRADE_PENDING) | |
146 | return F_RDLCK; | |
147 | return fl->fl_type; | |
ab83fa4b BF |
148 | } |
149 | ||
1da177e4 LT |
150 | int leases_enable = 1; |
151 | int lease_break_time = 45; | |
152 | ||
153 | #define for_each_lock(inode, lockp) \ | |
154 | for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) | |
155 | ||
1c8c601a JL |
156 | /* |
157 | * The global file_lock_list is only used for displaying /proc/locks. Protected | |
158 | * by the file_lock_lock. | |
159 | */ | |
26bcbf96 | 160 | static LIST_HEAD(file_lock_list); |
88974691 | 161 | |
1c8c601a JL |
162 | /* |
163 | * The blocked_list is used to find POSIX lock loops for deadlock detection. | |
164 | * Protected by file_lock_lock. | |
165 | */ | |
1da177e4 | 166 | static LIST_HEAD(blocked_list); |
88974691 | 167 | |
1c8c601a JL |
168 | /* |
169 | * This lock protects the blocked_list, and the file_lock_list. Generally, if | |
170 | * you're accessing one of those lists, you want to be holding this lock. | |
171 | * | |
172 | * In addition, it also protects the fl->fl_block list, and the fl->fl_next | |
173 | * pointer for file_lock structures that are acting as lock requests (in | |
174 | * contrast to those that are acting as records of acquired locks). | |
175 | * | |
176 | * Note that when we acquire this lock in order to change the above fields, | |
177 | * we often hold the i_lock as well. In certain cases, when reading the fields | |
178 | * protected by this lock, we can skip acquiring it iff we already hold the | |
179 | * i_lock. | |
180 | * | |
181 | * In particular, adding an entry to the fl_block list requires that you hold | |
182 | * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting | |
183 | * an entry from the list however only requires the file_lock_lock. | |
184 | */ | |
72f98e72 | 185 | static DEFINE_SPINLOCK(file_lock_lock); |
1da177e4 | 186 | |
e18b890b | 187 | static struct kmem_cache *filelock_cache __read_mostly; |
1da177e4 | 188 | |
ee19cc40 | 189 | static void locks_init_lock_heads(struct file_lock *fl) |
a51cb91d | 190 | { |
ee19cc40 MS |
191 | INIT_LIST_HEAD(&fl->fl_link); |
192 | INIT_LIST_HEAD(&fl->fl_block); | |
193 | init_waitqueue_head(&fl->fl_wait); | |
a51cb91d MS |
194 | } |
195 | ||
1da177e4 | 196 | /* Allocate an empty lock structure. */ |
c5b1f0d9 | 197 | struct file_lock *locks_alloc_lock(void) |
1da177e4 | 198 | { |
ee19cc40 | 199 | struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL); |
a51cb91d MS |
200 | |
201 | if (fl) | |
ee19cc40 | 202 | locks_init_lock_heads(fl); |
a51cb91d MS |
203 | |
204 | return fl; | |
1da177e4 | 205 | } |
c5b1f0d9 | 206 | EXPORT_SYMBOL_GPL(locks_alloc_lock); |
1da177e4 | 207 | |
a9e61e25 | 208 | void locks_release_private(struct file_lock *fl) |
47831f35 TM |
209 | { |
210 | if (fl->fl_ops) { | |
211 | if (fl->fl_ops->fl_release_private) | |
212 | fl->fl_ops->fl_release_private(fl); | |
213 | fl->fl_ops = NULL; | |
214 | } | |
068535f1 | 215 | fl->fl_lmops = NULL; |
47831f35 TM |
216 | |
217 | } | |
a9e61e25 | 218 | EXPORT_SYMBOL_GPL(locks_release_private); |
47831f35 | 219 | |
1da177e4 | 220 | /* Free a lock which is not in use. */ |
05fa3135 | 221 | void locks_free_lock(struct file_lock *fl) |
1da177e4 | 222 | { |
5ce29646 MS |
223 | BUG_ON(waitqueue_active(&fl->fl_wait)); |
224 | BUG_ON(!list_empty(&fl->fl_block)); | |
225 | BUG_ON(!list_empty(&fl->fl_link)); | |
1da177e4 | 226 | |
47831f35 | 227 | locks_release_private(fl); |
1da177e4 LT |
228 | kmem_cache_free(filelock_cache, fl); |
229 | } | |
05fa3135 | 230 | EXPORT_SYMBOL(locks_free_lock); |
1da177e4 LT |
231 | |
232 | void locks_init_lock(struct file_lock *fl) | |
233 | { | |
ee19cc40 MS |
234 | memset(fl, 0, sizeof(struct file_lock)); |
235 | locks_init_lock_heads(fl); | |
1da177e4 LT |
236 | } |
237 | ||
238 | EXPORT_SYMBOL(locks_init_lock); | |
239 | ||
47831f35 TM |
240 | static void locks_copy_private(struct file_lock *new, struct file_lock *fl) |
241 | { | |
242 | if (fl->fl_ops) { | |
243 | if (fl->fl_ops->fl_copy_lock) | |
244 | fl->fl_ops->fl_copy_lock(new, fl); | |
245 | new->fl_ops = fl->fl_ops; | |
246 | } | |
bb8430a2 | 247 | if (fl->fl_lmops) |
47831f35 | 248 | new->fl_lmops = fl->fl_lmops; |
47831f35 TM |
249 | } |
250 | ||
1da177e4 LT |
251 | /* |
252 | * Initialize a new lock from an existing file_lock structure. | |
253 | */ | |
1a747ee0 | 254 | void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl) |
1da177e4 LT |
255 | { |
256 | new->fl_owner = fl->fl_owner; | |
257 | new->fl_pid = fl->fl_pid; | |
0996905f | 258 | new->fl_file = NULL; |
1da177e4 LT |
259 | new->fl_flags = fl->fl_flags; |
260 | new->fl_type = fl->fl_type; | |
261 | new->fl_start = fl->fl_start; | |
262 | new->fl_end = fl->fl_end; | |
0996905f TM |
263 | new->fl_ops = NULL; |
264 | new->fl_lmops = NULL; | |
265 | } | |
3dd7b71c | 266 | EXPORT_SYMBOL(__locks_copy_lock); |
0996905f TM |
267 | |
268 | void locks_copy_lock(struct file_lock *new, struct file_lock *fl) | |
269 | { | |
270 | locks_release_private(new); | |
271 | ||
272 | __locks_copy_lock(new, fl); | |
273 | new->fl_file = fl->fl_file; | |
1da177e4 LT |
274 | new->fl_ops = fl->fl_ops; |
275 | new->fl_lmops = fl->fl_lmops; | |
47831f35 TM |
276 | |
277 | locks_copy_private(new, fl); | |
1da177e4 LT |
278 | } |
279 | ||
280 | EXPORT_SYMBOL(locks_copy_lock); | |
281 | ||
282 | static inline int flock_translate_cmd(int cmd) { | |
283 | if (cmd & LOCK_MAND) | |
284 | return cmd & (LOCK_MAND | LOCK_RW); | |
285 | switch (cmd) { | |
286 | case LOCK_SH: | |
287 | return F_RDLCK; | |
288 | case LOCK_EX: | |
289 | return F_WRLCK; | |
290 | case LOCK_UN: | |
291 | return F_UNLCK; | |
292 | } | |
293 | return -EINVAL; | |
294 | } | |
295 | ||
296 | /* Fill in a file_lock structure with an appropriate FLOCK lock. */ | |
297 | static int flock_make_lock(struct file *filp, struct file_lock **lock, | |
298 | unsigned int cmd) | |
299 | { | |
300 | struct file_lock *fl; | |
301 | int type = flock_translate_cmd(cmd); | |
302 | if (type < 0) | |
303 | return type; | |
304 | ||
305 | fl = locks_alloc_lock(); | |
306 | if (fl == NULL) | |
307 | return -ENOMEM; | |
308 | ||
309 | fl->fl_file = filp; | |
310 | fl->fl_pid = current->tgid; | |
311 | fl->fl_flags = FL_FLOCK; | |
312 | fl->fl_type = type; | |
313 | fl->fl_end = OFFSET_MAX; | |
314 | ||
315 | *lock = fl; | |
316 | return 0; | |
317 | } | |
318 | ||
0ec4f431 | 319 | static int assign_type(struct file_lock *fl, long type) |
1da177e4 LT |
320 | { |
321 | switch (type) { | |
322 | case F_RDLCK: | |
323 | case F_WRLCK: | |
324 | case F_UNLCK: | |
325 | fl->fl_type = type; | |
326 | break; | |
327 | default: | |
328 | return -EINVAL; | |
329 | } | |
330 | return 0; | |
331 | } | |
332 | ||
333 | /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX | |
334 | * style lock. | |
335 | */ | |
336 | static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, | |
337 | struct flock *l) | |
338 | { | |
339 | off_t start, end; | |
340 | ||
341 | switch (l->l_whence) { | |
f5579f8c | 342 | case SEEK_SET: |
1da177e4 LT |
343 | start = 0; |
344 | break; | |
f5579f8c | 345 | case SEEK_CUR: |
1da177e4 LT |
346 | start = filp->f_pos; |
347 | break; | |
f5579f8c | 348 | case SEEK_END: |
496ad9aa | 349 | start = i_size_read(file_inode(filp)); |
1da177e4 LT |
350 | break; |
351 | default: | |
352 | return -EINVAL; | |
353 | } | |
354 | ||
355 | /* POSIX-1996 leaves the case l->l_len < 0 undefined; | |
356 | POSIX-2001 defines it. */ | |
357 | start += l->l_start; | |
4c780a46 TM |
358 | if (start < 0) |
359 | return -EINVAL; | |
360 | fl->fl_end = OFFSET_MAX; | |
361 | if (l->l_len > 0) { | |
362 | end = start + l->l_len - 1; | |
363 | fl->fl_end = end; | |
364 | } else if (l->l_len < 0) { | |
1da177e4 | 365 | end = start - 1; |
4c780a46 | 366 | fl->fl_end = end; |
1da177e4 | 367 | start += l->l_len; |
4c780a46 TM |
368 | if (start < 0) |
369 | return -EINVAL; | |
1da177e4 | 370 | } |
1da177e4 | 371 | fl->fl_start = start; /* we record the absolute position */ |
4c780a46 TM |
372 | if (fl->fl_end < fl->fl_start) |
373 | return -EOVERFLOW; | |
1da177e4 LT |
374 | |
375 | fl->fl_owner = current->files; | |
376 | fl->fl_pid = current->tgid; | |
377 | fl->fl_file = filp; | |
378 | fl->fl_flags = FL_POSIX; | |
379 | fl->fl_ops = NULL; | |
380 | fl->fl_lmops = NULL; | |
381 | ||
382 | return assign_type(fl, l->l_type); | |
383 | } | |
384 | ||
385 | #if BITS_PER_LONG == 32 | |
386 | static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, | |
387 | struct flock64 *l) | |
388 | { | |
389 | loff_t start; | |
390 | ||
391 | switch (l->l_whence) { | |
f5579f8c | 392 | case SEEK_SET: |
1da177e4 LT |
393 | start = 0; |
394 | break; | |
f5579f8c | 395 | case SEEK_CUR: |
1da177e4 LT |
396 | start = filp->f_pos; |
397 | break; | |
f5579f8c | 398 | case SEEK_END: |
496ad9aa | 399 | start = i_size_read(file_inode(filp)); |
1da177e4 LT |
400 | break; |
401 | default: | |
402 | return -EINVAL; | |
403 | } | |
404 | ||
4c780a46 TM |
405 | start += l->l_start; |
406 | if (start < 0) | |
1da177e4 | 407 | return -EINVAL; |
4c780a46 TM |
408 | fl->fl_end = OFFSET_MAX; |
409 | if (l->l_len > 0) { | |
410 | fl->fl_end = start + l->l_len - 1; | |
411 | } else if (l->l_len < 0) { | |
412 | fl->fl_end = start - 1; | |
413 | start += l->l_len; | |
414 | if (start < 0) | |
415 | return -EINVAL; | |
416 | } | |
1da177e4 | 417 | fl->fl_start = start; /* we record the absolute position */ |
4c780a46 TM |
418 | if (fl->fl_end < fl->fl_start) |
419 | return -EOVERFLOW; | |
1da177e4 LT |
420 | |
421 | fl->fl_owner = current->files; | |
422 | fl->fl_pid = current->tgid; | |
423 | fl->fl_file = filp; | |
424 | fl->fl_flags = FL_POSIX; | |
425 | fl->fl_ops = NULL; | |
426 | fl->fl_lmops = NULL; | |
427 | ||
f32cb532 | 428 | return assign_type(fl, l->l_type); |
1da177e4 LT |
429 | } |
430 | #endif | |
431 | ||
432 | /* default lease lock manager operations */ | |
433 | static void lease_break_callback(struct file_lock *fl) | |
434 | { | |
435 | kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG); | |
436 | } | |
437 | ||
7b021967 | 438 | static const struct lock_manager_operations lease_manager_ops = { |
8fb47a4f | 439 | .lm_break = lease_break_callback, |
8fb47a4f | 440 | .lm_change = lease_modify, |
1da177e4 LT |
441 | }; |
442 | ||
443 | /* | |
444 | * Initialize a lease, use the default lock manager operations | |
445 | */ | |
0ec4f431 | 446 | static int lease_init(struct file *filp, long type, struct file_lock *fl) |
1da177e4 | 447 | { |
75dff55a TM |
448 | if (assign_type(fl, type) != 0) |
449 | return -EINVAL; | |
450 | ||
1da177e4 LT |
451 | fl->fl_owner = current->files; |
452 | fl->fl_pid = current->tgid; | |
453 | ||
454 | fl->fl_file = filp; | |
455 | fl->fl_flags = FL_LEASE; | |
1da177e4 LT |
456 | fl->fl_start = 0; |
457 | fl->fl_end = OFFSET_MAX; | |
458 | fl->fl_ops = NULL; | |
459 | fl->fl_lmops = &lease_manager_ops; | |
460 | return 0; | |
461 | } | |
462 | ||
463 | /* Allocate a file_lock initialised to this type of lease */ | |
0ec4f431 | 464 | static struct file_lock *lease_alloc(struct file *filp, long type) |
1da177e4 LT |
465 | { |
466 | struct file_lock *fl = locks_alloc_lock(); | |
75dff55a | 467 | int error = -ENOMEM; |
1da177e4 LT |
468 | |
469 | if (fl == NULL) | |
e32b8ee2 | 470 | return ERR_PTR(error); |
1da177e4 LT |
471 | |
472 | error = lease_init(filp, type, fl); | |
75dff55a TM |
473 | if (error) { |
474 | locks_free_lock(fl); | |
e32b8ee2 | 475 | return ERR_PTR(error); |
75dff55a | 476 | } |
e32b8ee2 | 477 | return fl; |
1da177e4 LT |
478 | } |
479 | ||
480 | /* Check if two locks overlap each other. | |
481 | */ | |
482 | static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2) | |
483 | { | |
484 | return ((fl1->fl_end >= fl2->fl_start) && | |
485 | (fl2->fl_end >= fl1->fl_start)); | |
486 | } | |
487 | ||
488 | /* | |
489 | * Check whether two locks have the same owner. | |
490 | */ | |
33443c42 | 491 | static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) |
1da177e4 | 492 | { |
8fb47a4f | 493 | if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner) |
1da177e4 | 494 | return fl2->fl_lmops == fl1->fl_lmops && |
8fb47a4f | 495 | fl1->fl_lmops->lm_compare_owner(fl1, fl2); |
1da177e4 LT |
496 | return fl1->fl_owner == fl2->fl_owner; |
497 | } | |
498 | ||
88974691 JL |
499 | static inline void |
500 | locks_insert_global_locks(struct file_lock *fl) | |
501 | { | |
1c8c601a | 502 | spin_lock(&file_lock_lock); |
88974691 | 503 | list_add_tail(&fl->fl_link, &file_lock_list); |
1c8c601a | 504 | spin_unlock(&file_lock_lock); |
88974691 JL |
505 | } |
506 | ||
507 | static inline void | |
508 | locks_delete_global_locks(struct file_lock *fl) | |
509 | { | |
1c8c601a | 510 | spin_lock(&file_lock_lock); |
88974691 | 511 | list_del_init(&fl->fl_link); |
1c8c601a | 512 | spin_unlock(&file_lock_lock); |
88974691 JL |
513 | } |
514 | ||
515 | static inline void | |
516 | locks_insert_global_blocked(struct file_lock *waiter) | |
517 | { | |
518 | list_add(&waiter->fl_link, &blocked_list); | |
519 | } | |
520 | ||
521 | static inline void | |
522 | locks_delete_global_blocked(struct file_lock *waiter) | |
523 | { | |
524 | list_del_init(&waiter->fl_link); | |
525 | } | |
526 | ||
1da177e4 LT |
527 | /* Remove waiter from blocker's block list. |
528 | * When blocker ends up pointing to itself then the list is empty. | |
1c8c601a JL |
529 | * |
530 | * Must be called with file_lock_lock held. | |
1da177e4 | 531 | */ |
33443c42 | 532 | static void __locks_delete_block(struct file_lock *waiter) |
1da177e4 | 533 | { |
88974691 | 534 | locks_delete_global_blocked(waiter); |
1da177e4 | 535 | list_del_init(&waiter->fl_block); |
1da177e4 LT |
536 | waiter->fl_next = NULL; |
537 | } | |
538 | ||
1a9e64a7 | 539 | static void locks_delete_block(struct file_lock *waiter) |
1da177e4 | 540 | { |
1c8c601a | 541 | spin_lock(&file_lock_lock); |
1da177e4 | 542 | __locks_delete_block(waiter); |
1c8c601a | 543 | spin_unlock(&file_lock_lock); |
1da177e4 LT |
544 | } |
545 | ||
546 | /* Insert waiter into blocker's block list. | |
547 | * We use a circular list so that processes can be easily woken up in | |
548 | * the order they blocked. The documentation doesn't require this but | |
549 | * it seems like the reasonable thing to do. | |
1c8c601a JL |
550 | * |
551 | * Must be called with file_lock_lock held! | |
1da177e4 | 552 | */ |
1c8c601a JL |
553 | static void __locks_insert_block(struct file_lock *blocker, |
554 | struct file_lock *waiter) | |
1da177e4 | 555 | { |
6dc0fe8f | 556 | BUG_ON(!list_empty(&waiter->fl_block)); |
1da177e4 | 557 | waiter->fl_next = blocker; |
88974691 | 558 | list_add_tail(&waiter->fl_block, &blocker->fl_block); |
1da177e4 | 559 | if (IS_POSIX(blocker)) |
1c8c601a JL |
560 | locks_insert_global_blocked(waiter); |
561 | } | |
562 | ||
563 | /* Must be called with i_lock held. */ | |
564 | static void locks_insert_block(struct file_lock *blocker, | |
565 | struct file_lock *waiter) | |
566 | { | |
567 | spin_lock(&file_lock_lock); | |
568 | __locks_insert_block(blocker, waiter); | |
569 | spin_unlock(&file_lock_lock); | |
1da177e4 LT |
570 | } |
571 | ||
1cb36012 JL |
572 | /* |
573 | * Wake up processes blocked waiting for blocker. | |
574 | * | |
1c8c601a | 575 | * Must be called with the inode->i_lock held! |
1da177e4 LT |
576 | */ |
577 | static void locks_wake_up_blocks(struct file_lock *blocker) | |
578 | { | |
1c8c601a | 579 | spin_lock(&file_lock_lock); |
1da177e4 | 580 | while (!list_empty(&blocker->fl_block)) { |
f0c1cd0e PE |
581 | struct file_lock *waiter; |
582 | ||
583 | waiter = list_first_entry(&blocker->fl_block, | |
1da177e4 LT |
584 | struct file_lock, fl_block); |
585 | __locks_delete_block(waiter); | |
8fb47a4f BF |
586 | if (waiter->fl_lmops && waiter->fl_lmops->lm_notify) |
587 | waiter->fl_lmops->lm_notify(waiter); | |
1da177e4 LT |
588 | else |
589 | wake_up(&waiter->fl_wait); | |
590 | } | |
1c8c601a | 591 | spin_unlock(&file_lock_lock); |
1da177e4 LT |
592 | } |
593 | ||
594 | /* Insert file lock fl into an inode's lock list at the position indicated | |
595 | * by pos. At the same time add the lock to the global file lock list. | |
1c8c601a JL |
596 | * |
597 | * Must be called with the i_lock held! | |
1da177e4 LT |
598 | */ |
599 | static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl) | |
600 | { | |
ab1f1611 VG |
601 | fl->fl_nspid = get_pid(task_tgid(current)); |
602 | ||
1da177e4 LT |
603 | /* insert into file's list */ |
604 | fl->fl_next = *pos; | |
605 | *pos = fl; | |
88974691 JL |
606 | |
607 | locks_insert_global_locks(fl); | |
1da177e4 LT |
608 | } |
609 | ||
610 | /* | |
611 | * Delete a lock and then free it. | |
612 | * Wake up processes that are blocked waiting for this lock, | |
613 | * notify the FS that the lock has been cleared and | |
614 | * finally free the lock. | |
1c8c601a JL |
615 | * |
616 | * Must be called with the i_lock held! | |
1da177e4 LT |
617 | */ |
618 | static void locks_delete_lock(struct file_lock **thisfl_p) | |
619 | { | |
620 | struct file_lock *fl = *thisfl_p; | |
621 | ||
88974691 JL |
622 | locks_delete_global_locks(fl); |
623 | ||
1da177e4 LT |
624 | *thisfl_p = fl->fl_next; |
625 | fl->fl_next = NULL; | |
1da177e4 | 626 | |
ab1f1611 VG |
627 | if (fl->fl_nspid) { |
628 | put_pid(fl->fl_nspid); | |
629 | fl->fl_nspid = NULL; | |
630 | } | |
631 | ||
1da177e4 LT |
632 | locks_wake_up_blocks(fl); |
633 | locks_free_lock(fl); | |
634 | } | |
635 | ||
636 | /* Determine if lock sys_fl blocks lock caller_fl. Common functionality | |
637 | * checks for shared/exclusive status of overlapping locks. | |
638 | */ | |
639 | static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
640 | { | |
641 | if (sys_fl->fl_type == F_WRLCK) | |
642 | return 1; | |
643 | if (caller_fl->fl_type == F_WRLCK) | |
644 | return 1; | |
645 | return 0; | |
646 | } | |
647 | ||
648 | /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific | |
649 | * checking before calling the locks_conflict(). | |
650 | */ | |
651 | static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
652 | { | |
653 | /* POSIX locks owned by the same process do not conflict with | |
654 | * each other. | |
655 | */ | |
656 | if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl)) | |
657 | return (0); | |
658 | ||
659 | /* Check whether they overlap */ | |
660 | if (!locks_overlap(caller_fl, sys_fl)) | |
661 | return 0; | |
662 | ||
663 | return (locks_conflict(caller_fl, sys_fl)); | |
664 | } | |
665 | ||
666 | /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific | |
667 | * checking before calling the locks_conflict(). | |
668 | */ | |
669 | static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
670 | { | |
671 | /* FLOCK locks referring to the same filp do not conflict with | |
672 | * each other. | |
673 | */ | |
674 | if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file)) | |
675 | return (0); | |
676 | if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND)) | |
677 | return 0; | |
678 | ||
679 | return (locks_conflict(caller_fl, sys_fl)); | |
680 | } | |
681 | ||
6d34ac19 | 682 | void |
9d6a8c5c | 683 | posix_test_lock(struct file *filp, struct file_lock *fl) |
1da177e4 LT |
684 | { |
685 | struct file_lock *cfl; | |
1c8c601a | 686 | struct inode *inode = file_inode(filp); |
1da177e4 | 687 | |
1c8c601a | 688 | spin_lock(&inode->i_lock); |
496ad9aa | 689 | for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) { |
1da177e4 LT |
690 | if (!IS_POSIX(cfl)) |
691 | continue; | |
b842e240 | 692 | if (posix_locks_conflict(fl, cfl)) |
1da177e4 LT |
693 | break; |
694 | } | |
ab1f1611 | 695 | if (cfl) { |
9d6a8c5c | 696 | __locks_copy_lock(fl, cfl); |
ab1f1611 | 697 | if (cfl->fl_nspid) |
6c5f3e7b | 698 | fl->fl_pid = pid_vnr(cfl->fl_nspid); |
ab1f1611 | 699 | } else |
129a84de | 700 | fl->fl_type = F_UNLCK; |
1c8c601a | 701 | spin_unlock(&inode->i_lock); |
6d34ac19 | 702 | return; |
1da177e4 | 703 | } |
1da177e4 LT |
704 | EXPORT_SYMBOL(posix_test_lock); |
705 | ||
b533184f BF |
706 | /* |
707 | * Deadlock detection: | |
708 | * | |
709 | * We attempt to detect deadlocks that are due purely to posix file | |
710 | * locks. | |
1da177e4 | 711 | * |
b533184f BF |
712 | * We assume that a task can be waiting for at most one lock at a time. |
713 | * So for any acquired lock, the process holding that lock may be | |
714 | * waiting on at most one other lock. That lock in turns may be held by | |
715 | * someone waiting for at most one other lock. Given a requested lock | |
716 | * caller_fl which is about to wait for a conflicting lock block_fl, we | |
717 | * follow this chain of waiters to ensure we are not about to create a | |
718 | * cycle. | |
1da177e4 | 719 | * |
b533184f BF |
720 | * Since we do this before we ever put a process to sleep on a lock, we |
721 | * are ensured that there is never a cycle; that is what guarantees that | |
722 | * the while() loop in posix_locks_deadlock() eventually completes. | |
97855b49 | 723 | * |
b533184f BF |
724 | * Note: the above assumption may not be true when handling lock |
725 | * requests from a broken NFS client. It may also fail in the presence | |
726 | * of tasks (such as posix threads) sharing the same open file table. | |
727 | * | |
728 | * To handle those cases, we just bail out after a few iterations. | |
1da177e4 | 729 | */ |
97855b49 BF |
730 | |
731 | #define MAX_DEADLK_ITERATIONS 10 | |
732 | ||
b533184f BF |
733 | /* Find a lock that the owner of the given block_fl is blocking on. */ |
734 | static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) | |
735 | { | |
736 | struct file_lock *fl; | |
737 | ||
738 | list_for_each_entry(fl, &blocked_list, fl_link) { | |
739 | if (posix_same_owner(fl, block_fl)) | |
740 | return fl->fl_next; | |
741 | } | |
742 | return NULL; | |
743 | } | |
744 | ||
1c8c601a | 745 | /* Must be called with the file_lock_lock held! */ |
b0904e14 | 746 | static int posix_locks_deadlock(struct file_lock *caller_fl, |
1da177e4 LT |
747 | struct file_lock *block_fl) |
748 | { | |
97855b49 | 749 | int i = 0; |
1da177e4 | 750 | |
b533184f BF |
751 | while ((block_fl = what_owner_is_waiting_for(block_fl))) { |
752 | if (i++ > MAX_DEADLK_ITERATIONS) | |
753 | return 0; | |
754 | if (posix_same_owner(caller_fl, block_fl)) | |
755 | return 1; | |
1da177e4 LT |
756 | } |
757 | return 0; | |
758 | } | |
759 | ||
1da177e4 | 760 | /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks |
02888f41 | 761 | * after any leases, but before any posix locks. |
f475ae95 TM |
762 | * |
763 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
764 | * whether or not a lock was successfully freed by testing the return | |
765 | * value for -ENOENT. | |
1da177e4 | 766 | */ |
993dfa87 | 767 | static int flock_lock_file(struct file *filp, struct file_lock *request) |
1da177e4 | 768 | { |
993dfa87 | 769 | struct file_lock *new_fl = NULL; |
1da177e4 | 770 | struct file_lock **before; |
496ad9aa | 771 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
772 | int error = 0; |
773 | int found = 0; | |
774 | ||
b89f4321 | 775 | if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) { |
84d535ad | 776 | new_fl = locks_alloc_lock(); |
b89f4321 AB |
777 | if (!new_fl) |
778 | return -ENOMEM; | |
84d535ad PE |
779 | } |
780 | ||
1c8c601a | 781 | spin_lock(&inode->i_lock); |
b89f4321 AB |
782 | if (request->fl_flags & FL_ACCESS) |
783 | goto find_conflict; | |
784 | ||
1da177e4 LT |
785 | for_each_lock(inode, before) { |
786 | struct file_lock *fl = *before; | |
787 | if (IS_POSIX(fl)) | |
788 | break; | |
789 | if (IS_LEASE(fl)) | |
790 | continue; | |
791 | if (filp != fl->fl_file) | |
792 | continue; | |
993dfa87 | 793 | if (request->fl_type == fl->fl_type) |
1da177e4 LT |
794 | goto out; |
795 | found = 1; | |
796 | locks_delete_lock(before); | |
797 | break; | |
798 | } | |
1da177e4 | 799 | |
f475ae95 TM |
800 | if (request->fl_type == F_UNLCK) { |
801 | if ((request->fl_flags & FL_EXISTS) && !found) | |
802 | error = -ENOENT; | |
993dfa87 | 803 | goto out; |
f475ae95 | 804 | } |
1da177e4 LT |
805 | |
806 | /* | |
807 | * If a higher-priority process was blocked on the old file lock, | |
808 | * give it the opportunity to lock the file. | |
809 | */ | |
b89f4321 | 810 | if (found) { |
1c8c601a | 811 | spin_unlock(&inode->i_lock); |
def01bc5 | 812 | cond_resched(); |
1c8c601a | 813 | spin_lock(&inode->i_lock); |
b89f4321 | 814 | } |
1da177e4 | 815 | |
f07f18dd | 816 | find_conflict: |
1da177e4 LT |
817 | for_each_lock(inode, before) { |
818 | struct file_lock *fl = *before; | |
819 | if (IS_POSIX(fl)) | |
820 | break; | |
821 | if (IS_LEASE(fl)) | |
822 | continue; | |
993dfa87 | 823 | if (!flock_locks_conflict(request, fl)) |
1da177e4 LT |
824 | continue; |
825 | error = -EAGAIN; | |
bde74e4b MS |
826 | if (!(request->fl_flags & FL_SLEEP)) |
827 | goto out; | |
828 | error = FILE_LOCK_DEFERRED; | |
829 | locks_insert_block(fl, request); | |
1da177e4 LT |
830 | goto out; |
831 | } | |
f07f18dd TM |
832 | if (request->fl_flags & FL_ACCESS) |
833 | goto out; | |
993dfa87 | 834 | locks_copy_lock(new_fl, request); |
0e2f6db8 | 835 | locks_insert_lock(before, new_fl); |
993dfa87 | 836 | new_fl = NULL; |
9cedc194 | 837 | error = 0; |
1da177e4 LT |
838 | |
839 | out: | |
1c8c601a | 840 | spin_unlock(&inode->i_lock); |
993dfa87 TM |
841 | if (new_fl) |
842 | locks_free_lock(new_fl); | |
1da177e4 LT |
843 | return error; |
844 | } | |
845 | ||
150b3934 | 846 | static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock) |
1da177e4 LT |
847 | { |
848 | struct file_lock *fl; | |
39005d02 MS |
849 | struct file_lock *new_fl = NULL; |
850 | struct file_lock *new_fl2 = NULL; | |
1da177e4 LT |
851 | struct file_lock *left = NULL; |
852 | struct file_lock *right = NULL; | |
853 | struct file_lock **before; | |
b9746ef8 JL |
854 | int error; |
855 | bool added = false; | |
1da177e4 LT |
856 | |
857 | /* | |
858 | * We may need two file_lock structures for this operation, | |
859 | * so we get them in advance to avoid races. | |
39005d02 MS |
860 | * |
861 | * In some cases we can be sure, that no new locks will be needed | |
1da177e4 | 862 | */ |
39005d02 MS |
863 | if (!(request->fl_flags & FL_ACCESS) && |
864 | (request->fl_type != F_UNLCK || | |
865 | request->fl_start != 0 || request->fl_end != OFFSET_MAX)) { | |
866 | new_fl = locks_alloc_lock(); | |
867 | new_fl2 = locks_alloc_lock(); | |
868 | } | |
1da177e4 | 869 | |
1c8c601a | 870 | spin_lock(&inode->i_lock); |
1cb36012 JL |
871 | /* |
872 | * New lock request. Walk all POSIX locks and look for conflicts. If | |
873 | * there are any, either return error or put the request on the | |
874 | * blocker's list of waiters and the global blocked_list. | |
875 | */ | |
1da177e4 LT |
876 | if (request->fl_type != F_UNLCK) { |
877 | for_each_lock(inode, before) { | |
526985b9 | 878 | fl = *before; |
1da177e4 LT |
879 | if (!IS_POSIX(fl)) |
880 | continue; | |
881 | if (!posix_locks_conflict(request, fl)) | |
882 | continue; | |
5842add2 | 883 | if (conflock) |
1a747ee0 | 884 | __locks_copy_lock(conflock, fl); |
1da177e4 LT |
885 | error = -EAGAIN; |
886 | if (!(request->fl_flags & FL_SLEEP)) | |
887 | goto out; | |
1c8c601a JL |
888 | /* |
889 | * Deadlock detection and insertion into the blocked | |
890 | * locks list must be done while holding the same lock! | |
891 | */ | |
1da177e4 | 892 | error = -EDEADLK; |
1c8c601a JL |
893 | spin_lock(&file_lock_lock); |
894 | if (likely(!posix_locks_deadlock(request, fl))) { | |
895 | error = FILE_LOCK_DEFERRED; | |
896 | __locks_insert_block(fl, request); | |
897 | } | |
898 | spin_unlock(&file_lock_lock); | |
1da177e4 LT |
899 | goto out; |
900 | } | |
901 | } | |
902 | ||
903 | /* If we're just looking for a conflict, we're done. */ | |
904 | error = 0; | |
905 | if (request->fl_flags & FL_ACCESS) | |
906 | goto out; | |
907 | ||
1da177e4 | 908 | /* |
1da177e4 LT |
909 | * Find the first old lock with the same owner as the new lock. |
910 | */ | |
911 | ||
912 | before = &inode->i_flock; | |
913 | ||
914 | /* First skip locks owned by other processes. */ | |
915 | while ((fl = *before) && (!IS_POSIX(fl) || | |
916 | !posix_same_owner(request, fl))) { | |
917 | before = &fl->fl_next; | |
918 | } | |
919 | ||
1cb36012 | 920 | /* Process locks with this owner. */ |
1da177e4 LT |
921 | while ((fl = *before) && posix_same_owner(request, fl)) { |
922 | /* Detect adjacent or overlapping regions (if same lock type) | |
923 | */ | |
924 | if (request->fl_type == fl->fl_type) { | |
449231d6 OK |
925 | /* In all comparisons of start vs end, use |
926 | * "start - 1" rather than "end + 1". If end | |
927 | * is OFFSET_MAX, end + 1 will become negative. | |
928 | */ | |
1da177e4 LT |
929 | if (fl->fl_end < request->fl_start - 1) |
930 | goto next_lock; | |
931 | /* If the next lock in the list has entirely bigger | |
932 | * addresses than the new one, insert the lock here. | |
933 | */ | |
449231d6 | 934 | if (fl->fl_start - 1 > request->fl_end) |
1da177e4 LT |
935 | break; |
936 | ||
937 | /* If we come here, the new and old lock are of the | |
938 | * same type and adjacent or overlapping. Make one | |
939 | * lock yielding from the lower start address of both | |
940 | * locks to the higher end address. | |
941 | */ | |
942 | if (fl->fl_start > request->fl_start) | |
943 | fl->fl_start = request->fl_start; | |
944 | else | |
945 | request->fl_start = fl->fl_start; | |
946 | if (fl->fl_end < request->fl_end) | |
947 | fl->fl_end = request->fl_end; | |
948 | else | |
949 | request->fl_end = fl->fl_end; | |
950 | if (added) { | |
951 | locks_delete_lock(before); | |
952 | continue; | |
953 | } | |
954 | request = fl; | |
b9746ef8 | 955 | added = true; |
1da177e4 LT |
956 | } |
957 | else { | |
958 | /* Processing for different lock types is a bit | |
959 | * more complex. | |
960 | */ | |
961 | if (fl->fl_end < request->fl_start) | |
962 | goto next_lock; | |
963 | if (fl->fl_start > request->fl_end) | |
964 | break; | |
965 | if (request->fl_type == F_UNLCK) | |
b9746ef8 | 966 | added = true; |
1da177e4 LT |
967 | if (fl->fl_start < request->fl_start) |
968 | left = fl; | |
969 | /* If the next lock in the list has a higher end | |
970 | * address than the new one, insert the new one here. | |
971 | */ | |
972 | if (fl->fl_end > request->fl_end) { | |
973 | right = fl; | |
974 | break; | |
975 | } | |
976 | if (fl->fl_start >= request->fl_start) { | |
977 | /* The new lock completely replaces an old | |
978 | * one (This may happen several times). | |
979 | */ | |
980 | if (added) { | |
981 | locks_delete_lock(before); | |
982 | continue; | |
983 | } | |
984 | /* Replace the old lock with the new one. | |
985 | * Wake up anybody waiting for the old one, | |
986 | * as the change in lock type might satisfy | |
987 | * their needs. | |
988 | */ | |
989 | locks_wake_up_blocks(fl); | |
990 | fl->fl_start = request->fl_start; | |
991 | fl->fl_end = request->fl_end; | |
992 | fl->fl_type = request->fl_type; | |
47831f35 TM |
993 | locks_release_private(fl); |
994 | locks_copy_private(fl, request); | |
1da177e4 | 995 | request = fl; |
b9746ef8 | 996 | added = true; |
1da177e4 LT |
997 | } |
998 | } | |
999 | /* Go on to next lock. | |
1000 | */ | |
1001 | next_lock: | |
1002 | before = &fl->fl_next; | |
1003 | } | |
1004 | ||
0d9a490a | 1005 | /* |
1cb36012 JL |
1006 | * The above code only modifies existing locks in case of merging or |
1007 | * replacing. If new lock(s) need to be inserted all modifications are | |
1008 | * done below this, so it's safe yet to bail out. | |
0d9a490a MS |
1009 | */ |
1010 | error = -ENOLCK; /* "no luck" */ | |
1011 | if (right && left == right && !new_fl2) | |
1012 | goto out; | |
1013 | ||
1da177e4 LT |
1014 | error = 0; |
1015 | if (!added) { | |
f475ae95 TM |
1016 | if (request->fl_type == F_UNLCK) { |
1017 | if (request->fl_flags & FL_EXISTS) | |
1018 | error = -ENOENT; | |
1da177e4 | 1019 | goto out; |
f475ae95 | 1020 | } |
0d9a490a MS |
1021 | |
1022 | if (!new_fl) { | |
1023 | error = -ENOLCK; | |
1024 | goto out; | |
1025 | } | |
1da177e4 LT |
1026 | locks_copy_lock(new_fl, request); |
1027 | locks_insert_lock(before, new_fl); | |
1028 | new_fl = NULL; | |
1029 | } | |
1030 | if (right) { | |
1031 | if (left == right) { | |
1032 | /* The new lock breaks the old one in two pieces, | |
1033 | * so we have to use the second new lock. | |
1034 | */ | |
1035 | left = new_fl2; | |
1036 | new_fl2 = NULL; | |
1037 | locks_copy_lock(left, right); | |
1038 | locks_insert_lock(before, left); | |
1039 | } | |
1040 | right->fl_start = request->fl_end + 1; | |
1041 | locks_wake_up_blocks(right); | |
1042 | } | |
1043 | if (left) { | |
1044 | left->fl_end = request->fl_start - 1; | |
1045 | locks_wake_up_blocks(left); | |
1046 | } | |
1047 | out: | |
1c8c601a | 1048 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1049 | /* |
1050 | * Free any unused locks. | |
1051 | */ | |
1052 | if (new_fl) | |
1053 | locks_free_lock(new_fl); | |
1054 | if (new_fl2) | |
1055 | locks_free_lock(new_fl2); | |
1056 | return error; | |
1057 | } | |
1058 | ||
1059 | /** | |
1060 | * posix_lock_file - Apply a POSIX-style lock to a file | |
1061 | * @filp: The file to apply the lock to | |
1062 | * @fl: The lock to be applied | |
150b3934 | 1063 | * @conflock: Place to return a copy of the conflicting lock, if found. |
1da177e4 LT |
1064 | * |
1065 | * Add a POSIX style lock to a file. | |
1066 | * We merge adjacent & overlapping locks whenever possible. | |
1067 | * POSIX locks are sorted by owner task, then by starting address | |
f475ae95 TM |
1068 | * |
1069 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
1070 | * whether or not a lock was successfully freed by testing the return | |
1071 | * value for -ENOENT. | |
1da177e4 | 1072 | */ |
150b3934 | 1073 | int posix_lock_file(struct file *filp, struct file_lock *fl, |
5842add2 AA |
1074 | struct file_lock *conflock) |
1075 | { | |
496ad9aa | 1076 | return __posix_lock_file(file_inode(filp), fl, conflock); |
1da177e4 | 1077 | } |
150b3934 | 1078 | EXPORT_SYMBOL(posix_lock_file); |
1da177e4 LT |
1079 | |
1080 | /** | |
1081 | * posix_lock_file_wait - Apply a POSIX-style lock to a file | |
1082 | * @filp: The file to apply the lock to | |
1083 | * @fl: The lock to be applied | |
1084 | * | |
1085 | * Add a POSIX style lock to a file. | |
1086 | * We merge adjacent & overlapping locks whenever possible. | |
1087 | * POSIX locks are sorted by owner task, then by starting address | |
1088 | */ | |
1089 | int posix_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1090 | { | |
1091 | int error; | |
1092 | might_sleep (); | |
1093 | for (;;) { | |
150b3934 | 1094 | error = posix_lock_file(filp, fl, NULL); |
bde74e4b | 1095 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1096 | break; |
1097 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1098 | if (!error) | |
1099 | continue; | |
1100 | ||
1101 | locks_delete_block(fl); | |
1102 | break; | |
1103 | } | |
1104 | return error; | |
1105 | } | |
1106 | EXPORT_SYMBOL(posix_lock_file_wait); | |
1107 | ||
1108 | /** | |
1109 | * locks_mandatory_locked - Check for an active lock | |
1110 | * @inode: the file to check | |
1111 | * | |
1112 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1113 | * This function is called from locks_verify_locked() only. | |
1114 | */ | |
1115 | int locks_mandatory_locked(struct inode *inode) | |
1116 | { | |
1117 | fl_owner_t owner = current->files; | |
1118 | struct file_lock *fl; | |
1119 | ||
1120 | /* | |
1121 | * Search the lock list for this inode for any POSIX locks. | |
1122 | */ | |
1c8c601a | 1123 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1124 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
1125 | if (!IS_POSIX(fl)) | |
1126 | continue; | |
1127 | if (fl->fl_owner != owner) | |
1128 | break; | |
1129 | } | |
1c8c601a | 1130 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1131 | return fl ? -EAGAIN : 0; |
1132 | } | |
1133 | ||
1134 | /** | |
1135 | * locks_mandatory_area - Check for a conflicting lock | |
1136 | * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ | |
1137 | * for shared | |
1138 | * @inode: the file to check | |
1139 | * @filp: how the file was opened (if it was) | |
1140 | * @offset: start of area to check | |
1141 | * @count: length of area to check | |
1142 | * | |
1143 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1144 | * This function is called from rw_verify_area() and | |
1145 | * locks_verify_truncate(). | |
1146 | */ | |
1147 | int locks_mandatory_area(int read_write, struct inode *inode, | |
1148 | struct file *filp, loff_t offset, | |
1149 | size_t count) | |
1150 | { | |
1151 | struct file_lock fl; | |
1152 | int error; | |
1153 | ||
1154 | locks_init_lock(&fl); | |
1155 | fl.fl_owner = current->files; | |
1156 | fl.fl_pid = current->tgid; | |
1157 | fl.fl_file = filp; | |
1158 | fl.fl_flags = FL_POSIX | FL_ACCESS; | |
1159 | if (filp && !(filp->f_flags & O_NONBLOCK)) | |
1160 | fl.fl_flags |= FL_SLEEP; | |
1161 | fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK; | |
1162 | fl.fl_start = offset; | |
1163 | fl.fl_end = offset + count - 1; | |
1164 | ||
1165 | for (;;) { | |
150b3934 | 1166 | error = __posix_lock_file(inode, &fl, NULL); |
bde74e4b | 1167 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1168 | break; |
1169 | error = wait_event_interruptible(fl.fl_wait, !fl.fl_next); | |
1170 | if (!error) { | |
1171 | /* | |
1172 | * If we've been sleeping someone might have | |
1173 | * changed the permissions behind our back. | |
1174 | */ | |
a16877ca | 1175 | if (__mandatory_lock(inode)) |
1da177e4 LT |
1176 | continue; |
1177 | } | |
1178 | ||
1179 | locks_delete_block(&fl); | |
1180 | break; | |
1181 | } | |
1182 | ||
1183 | return error; | |
1184 | } | |
1185 | ||
1186 | EXPORT_SYMBOL(locks_mandatory_area); | |
1187 | ||
778fc546 BF |
1188 | static void lease_clear_pending(struct file_lock *fl, int arg) |
1189 | { | |
1190 | switch (arg) { | |
1191 | case F_UNLCK: | |
1192 | fl->fl_flags &= ~FL_UNLOCK_PENDING; | |
1193 | /* fall through: */ | |
1194 | case F_RDLCK: | |
1195 | fl->fl_flags &= ~FL_DOWNGRADE_PENDING; | |
1196 | } | |
1197 | } | |
1198 | ||
1da177e4 LT |
1199 | /* We already had a lease on this file; just change its type */ |
1200 | int lease_modify(struct file_lock **before, int arg) | |
1201 | { | |
1202 | struct file_lock *fl = *before; | |
1203 | int error = assign_type(fl, arg); | |
1204 | ||
1205 | if (error) | |
1206 | return error; | |
778fc546 | 1207 | lease_clear_pending(fl, arg); |
1da177e4 | 1208 | locks_wake_up_blocks(fl); |
3b6e2723 FB |
1209 | if (arg == F_UNLCK) { |
1210 | struct file *filp = fl->fl_file; | |
1211 | ||
1212 | f_delown(filp); | |
1213 | filp->f_owner.signum = 0; | |
96d6d59c BF |
1214 | fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync); |
1215 | if (fl->fl_fasync != NULL) { | |
1216 | printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync); | |
1217 | fl->fl_fasync = NULL; | |
1218 | } | |
1da177e4 | 1219 | locks_delete_lock(before); |
3b6e2723 | 1220 | } |
1da177e4 LT |
1221 | return 0; |
1222 | } | |
1223 | ||
1224 | EXPORT_SYMBOL(lease_modify); | |
1225 | ||
778fc546 BF |
1226 | static bool past_time(unsigned long then) |
1227 | { | |
1228 | if (!then) | |
1229 | /* 0 is a special value meaning "this never expires": */ | |
1230 | return false; | |
1231 | return time_after(jiffies, then); | |
1232 | } | |
1233 | ||
1da177e4 LT |
1234 | static void time_out_leases(struct inode *inode) |
1235 | { | |
1236 | struct file_lock **before; | |
1237 | struct file_lock *fl; | |
1238 | ||
1239 | before = &inode->i_flock; | |
ab83fa4b | 1240 | while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) { |
778fc546 BF |
1241 | if (past_time(fl->fl_downgrade_time)) |
1242 | lease_modify(before, F_RDLCK); | |
1243 | if (past_time(fl->fl_break_time)) | |
1244 | lease_modify(before, F_UNLCK); | |
1da177e4 LT |
1245 | if (fl == *before) /* lease_modify may have freed fl */ |
1246 | before = &fl->fl_next; | |
1247 | } | |
1248 | } | |
1249 | ||
1250 | /** | |
1251 | * __break_lease - revoke all outstanding leases on file | |
1252 | * @inode: the inode of the file to return | |
1253 | * @mode: the open mode (read or write) | |
1254 | * | |
87250dd2 | 1255 | * break_lease (inlined for speed) has checked there already is at least |
1256 | * some kind of lock (maybe a lease) on this file. Leases are broken on | |
1257 | * a call to open() or truncate(). This function can sleep unless you | |
1da177e4 LT |
1258 | * specified %O_NONBLOCK to your open(). |
1259 | */ | |
1260 | int __break_lease(struct inode *inode, unsigned int mode) | |
1261 | { | |
778fc546 | 1262 | int error = 0; |
1da177e4 LT |
1263 | struct file_lock *new_fl, *flock; |
1264 | struct file_lock *fl; | |
1da177e4 LT |
1265 | unsigned long break_time; |
1266 | int i_have_this_lease = 0; | |
8737c930 | 1267 | int want_write = (mode & O_ACCMODE) != O_RDONLY; |
1da177e4 | 1268 | |
8737c930 | 1269 | new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK); |
6d4b9e38 LT |
1270 | if (IS_ERR(new_fl)) |
1271 | return PTR_ERR(new_fl); | |
1da177e4 | 1272 | |
1c8c601a | 1273 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1274 | |
1275 | time_out_leases(inode); | |
1276 | ||
1277 | flock = inode->i_flock; | |
1278 | if ((flock == NULL) || !IS_LEASE(flock)) | |
1279 | goto out; | |
1280 | ||
778fc546 BF |
1281 | if (!locks_conflict(flock, new_fl)) |
1282 | goto out; | |
1283 | ||
1da177e4 LT |
1284 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) |
1285 | if (fl->fl_owner == current->files) | |
1286 | i_have_this_lease = 1; | |
1287 | ||
1da177e4 LT |
1288 | break_time = 0; |
1289 | if (lease_break_time > 0) { | |
1290 | break_time = jiffies + lease_break_time * HZ; | |
1291 | if (break_time == 0) | |
1292 | break_time++; /* so that 0 means no break time */ | |
1293 | } | |
1294 | ||
1295 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { | |
778fc546 BF |
1296 | if (want_write) { |
1297 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1298 | continue; | |
1299 | fl->fl_flags |= FL_UNLOCK_PENDING; | |
1da177e4 | 1300 | fl->fl_break_time = break_time; |
778fc546 BF |
1301 | } else { |
1302 | if (lease_breaking(flock)) | |
1303 | continue; | |
1304 | fl->fl_flags |= FL_DOWNGRADE_PENDING; | |
1305 | fl->fl_downgrade_time = break_time; | |
1da177e4 | 1306 | } |
778fc546 | 1307 | fl->fl_lmops->lm_break(fl); |
1da177e4 LT |
1308 | } |
1309 | ||
1310 | if (i_have_this_lease || (mode & O_NONBLOCK)) { | |
1311 | error = -EWOULDBLOCK; | |
1312 | goto out; | |
1313 | } | |
1314 | ||
1315 | restart: | |
1316 | break_time = flock->fl_break_time; | |
1317 | if (break_time != 0) { | |
1318 | break_time -= jiffies; | |
1319 | if (break_time == 0) | |
1320 | break_time++; | |
1321 | } | |
4321e01e | 1322 | locks_insert_block(flock, new_fl); |
1c8c601a | 1323 | spin_unlock(&inode->i_lock); |
4321e01e MW |
1324 | error = wait_event_interruptible_timeout(new_fl->fl_wait, |
1325 | !new_fl->fl_next, break_time); | |
1c8c601a JL |
1326 | spin_lock(&inode->i_lock); |
1327 | locks_delete_block(new_fl); | |
1da177e4 LT |
1328 | if (error >= 0) { |
1329 | if (error == 0) | |
1330 | time_out_leases(inode); | |
778fc546 BF |
1331 | /* |
1332 | * Wait for the next conflicting lease that has not been | |
1333 | * broken yet | |
1334 | */ | |
1da177e4 LT |
1335 | for (flock = inode->i_flock; flock && IS_LEASE(flock); |
1336 | flock = flock->fl_next) { | |
778fc546 | 1337 | if (locks_conflict(new_fl, flock)) |
1da177e4 LT |
1338 | goto restart; |
1339 | } | |
1340 | error = 0; | |
1341 | } | |
1342 | ||
1343 | out: | |
1c8c601a | 1344 | spin_unlock(&inode->i_lock); |
6d4b9e38 | 1345 | locks_free_lock(new_fl); |
1da177e4 LT |
1346 | return error; |
1347 | } | |
1348 | ||
1349 | EXPORT_SYMBOL(__break_lease); | |
1350 | ||
1351 | /** | |
a6b91919 | 1352 | * lease_get_mtime - get the last modified time of an inode |
1da177e4 LT |
1353 | * @inode: the inode |
1354 | * @time: pointer to a timespec which will contain the last modified time | |
1355 | * | |
1356 | * This is to force NFS clients to flush their caches for files with | |
1357 | * exclusive leases. The justification is that if someone has an | |
a6b91919 | 1358 | * exclusive lease, then they could be modifying it. |
1da177e4 LT |
1359 | */ |
1360 | void lease_get_mtime(struct inode *inode, struct timespec *time) | |
1361 | { | |
1362 | struct file_lock *flock = inode->i_flock; | |
0ee5c6d6 | 1363 | if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK)) |
1da177e4 LT |
1364 | *time = current_fs_time(inode->i_sb); |
1365 | else | |
1366 | *time = inode->i_mtime; | |
1367 | } | |
1368 | ||
1369 | EXPORT_SYMBOL(lease_get_mtime); | |
1370 | ||
1371 | /** | |
1372 | * fcntl_getlease - Enquire what lease is currently active | |
1373 | * @filp: the file | |
1374 | * | |
1375 | * The value returned by this function will be one of | |
1376 | * (if no lease break is pending): | |
1377 | * | |
1378 | * %F_RDLCK to indicate a shared lease is held. | |
1379 | * | |
1380 | * %F_WRLCK to indicate an exclusive lease is held. | |
1381 | * | |
1382 | * %F_UNLCK to indicate no lease is held. | |
1383 | * | |
1384 | * (if a lease break is pending): | |
1385 | * | |
1386 | * %F_RDLCK to indicate an exclusive lease needs to be | |
1387 | * changed to a shared lease (or removed). | |
1388 | * | |
1389 | * %F_UNLCK to indicate the lease needs to be removed. | |
1390 | * | |
1391 | * XXX: sfr & willy disagree over whether F_INPROGRESS | |
1392 | * should be returned to userspace. | |
1393 | */ | |
1394 | int fcntl_getlease(struct file *filp) | |
1395 | { | |
1396 | struct file_lock *fl; | |
1c8c601a | 1397 | struct inode *inode = file_inode(filp); |
1da177e4 LT |
1398 | int type = F_UNLCK; |
1399 | ||
1c8c601a | 1400 | spin_lock(&inode->i_lock); |
496ad9aa AV |
1401 | time_out_leases(file_inode(filp)); |
1402 | for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl); | |
1da177e4 LT |
1403 | fl = fl->fl_next) { |
1404 | if (fl->fl_file == filp) { | |
778fc546 | 1405 | type = target_leasetype(fl); |
1da177e4 LT |
1406 | break; |
1407 | } | |
1408 | } | |
1c8c601a | 1409 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1410 | return type; |
1411 | } | |
1412 | ||
d4f22d19 | 1413 | static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp) |
1da177e4 | 1414 | { |
7eaae282 | 1415 | struct file_lock *fl, **before, **my_before = NULL, *lease; |
0f7fc9e4 | 1416 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 1417 | struct inode *inode = dentry->d_inode; |
c1f24ef4 | 1418 | int error; |
1da177e4 | 1419 | |
096657b6 BF |
1420 | lease = *flp; |
1421 | ||
8335ebd9 BF |
1422 | error = -EAGAIN; |
1423 | if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) | |
096657b6 | 1424 | goto out; |
8335ebd9 BF |
1425 | if ((arg == F_WRLCK) |
1426 | && ((dentry->d_count > 1) | |
1427 | || (atomic_read(&inode->i_count) > 1))) | |
096657b6 | 1428 | goto out; |
6d5e8b05 | 1429 | |
1da177e4 LT |
1430 | /* |
1431 | * At this point, we know that if there is an exclusive | |
1432 | * lease on this file, then we hold it on this filp | |
1433 | * (otherwise our open of this file would have blocked). | |
1434 | * And if we are trying to acquire an exclusive lease, | |
1435 | * then the file is not open by anyone (including us) | |
1436 | * except for this filp. | |
1437 | */ | |
c1f24ef4 | 1438 | error = -EAGAIN; |
1da177e4 LT |
1439 | for (before = &inode->i_flock; |
1440 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1441 | before = &fl->fl_next) { | |
c1f24ef4 | 1442 | if (fl->fl_file == filp) { |
1da177e4 | 1443 | my_before = before; |
c1f24ef4 BF |
1444 | continue; |
1445 | } | |
1446 | /* | |
1447 | * No exclusive leases if someone else has a lease on | |
1448 | * this file: | |
1449 | */ | |
1450 | if (arg == F_WRLCK) | |
1451 | goto out; | |
1452 | /* | |
1453 | * Modifying our existing lease is OK, but no getting a | |
1454 | * new lease if someone else is opening for write: | |
1455 | */ | |
1456 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1457 | goto out; | |
1da177e4 LT |
1458 | } |
1459 | ||
1da177e4 | 1460 | if (my_before != NULL) { |
8fb47a4f | 1461 | error = lease->fl_lmops->lm_change(my_before, arg); |
51ee4b84 CH |
1462 | if (!error) |
1463 | *flp = *my_before; | |
1da177e4 LT |
1464 | goto out; |
1465 | } | |
1466 | ||
1da177e4 LT |
1467 | error = -EINVAL; |
1468 | if (!leases_enable) | |
1469 | goto out; | |
1470 | ||
c5b1f0d9 | 1471 | locks_insert_lock(before, lease); |
85c59580 | 1472 | return 0; |
1da177e4 | 1473 | |
1da177e4 LT |
1474 | out: |
1475 | return error; | |
1476 | } | |
8335ebd9 | 1477 | |
d4f22d19 | 1478 | static int generic_delete_lease(struct file *filp, struct file_lock **flp) |
8335ebd9 BF |
1479 | { |
1480 | struct file_lock *fl, **before; | |
1481 | struct dentry *dentry = filp->f_path.dentry; | |
1482 | struct inode *inode = dentry->d_inode; | |
1483 | ||
1484 | for (before = &inode->i_flock; | |
1485 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1486 | before = &fl->fl_next) { | |
1487 | if (fl->fl_file != filp) | |
1488 | continue; | |
1489 | return (*flp)->fl_lmops->lm_change(before, F_UNLCK); | |
1490 | } | |
1491 | return -EAGAIN; | |
1492 | } | |
1493 | ||
1494 | /** | |
1495 | * generic_setlease - sets a lease on an open file | |
1496 | * @filp: file pointer | |
1497 | * @arg: type of lease to obtain | |
1498 | * @flp: input - file_lock to use, output - file_lock inserted | |
1499 | * | |
1500 | * The (input) flp->fl_lmops->lm_break function is required | |
1501 | * by break_lease(). | |
1502 | * | |
1c8c601a | 1503 | * Called with inode->i_lock held. |
8335ebd9 BF |
1504 | */ |
1505 | int generic_setlease(struct file *filp, long arg, struct file_lock **flp) | |
1506 | { | |
1507 | struct dentry *dentry = filp->f_path.dentry; | |
1508 | struct inode *inode = dentry->d_inode; | |
1509 | int error; | |
1510 | ||
8e96e3b7 | 1511 | if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE)) |
8335ebd9 BF |
1512 | return -EACCES; |
1513 | if (!S_ISREG(inode->i_mode)) | |
1514 | return -EINVAL; | |
1515 | error = security_file_lock(filp, arg); | |
1516 | if (error) | |
1517 | return error; | |
1518 | ||
1519 | time_out_leases(inode); | |
1520 | ||
1521 | BUG_ON(!(*flp)->fl_lmops->lm_break); | |
1522 | ||
1523 | switch (arg) { | |
1524 | case F_UNLCK: | |
1525 | return generic_delete_lease(filp, flp); | |
1526 | case F_RDLCK: | |
1527 | case F_WRLCK: | |
1528 | return generic_add_lease(filp, arg, flp); | |
1529 | default: | |
8d657eb3 | 1530 | return -EINVAL; |
8335ebd9 BF |
1531 | } |
1532 | } | |
0af1a450 | 1533 | EXPORT_SYMBOL(generic_setlease); |
1da177e4 | 1534 | |
b89f4321 AB |
1535 | static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1536 | { | |
1537 | if (filp->f_op && filp->f_op->setlease) | |
1538 | return filp->f_op->setlease(filp, arg, lease); | |
1539 | else | |
1540 | return generic_setlease(filp, arg, lease); | |
1541 | } | |
1542 | ||
1543 | /** | |
a9933cea | 1544 | * vfs_setlease - sets a lease on an open file |
1da177e4 LT |
1545 | * @filp: file pointer |
1546 | * @arg: type of lease to obtain | |
1547 | * @lease: file_lock to use | |
1548 | * | |
1549 | * Call this to establish a lease on the file. | |
8fb47a4f | 1550 | * The (*lease)->fl_lmops->lm_break operation must be set; if not, |
f9ffed26 BF |
1551 | * break_lease will oops! |
1552 | * | |
1553 | * This will call the filesystem's setlease file method, if | |
1554 | * defined. Note that there is no getlease method; instead, the | |
1555 | * filesystem setlease method should call back to setlease() to | |
1556 | * add a lease to the inode's lease list, where fcntl_getlease() can | |
1557 | * find it. Since fcntl_getlease() only reports whether the current | |
1558 | * task holds a lease, a cluster filesystem need only do this for | |
1559 | * leases held by processes on this node. | |
1560 | * | |
1561 | * There is also no break_lease method; filesystems that | |
c9404c9c | 1562 | * handle their own leases should break leases themselves from the |
f9ffed26 BF |
1563 | * filesystem's open, create, and (on truncate) setattr methods. |
1564 | * | |
1565 | * Warning: the only current setlease methods exist only to disable | |
1566 | * leases in certain cases. More vfs changes may be required to | |
1567 | * allow a full filesystem lease implementation. | |
1da177e4 LT |
1568 | */ |
1569 | ||
a9933cea | 1570 | int vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1da177e4 | 1571 | { |
1c8c601a | 1572 | struct inode *inode = file_inode(filp); |
1da177e4 LT |
1573 | int error; |
1574 | ||
1c8c601a | 1575 | spin_lock(&inode->i_lock); |
b89f4321 | 1576 | error = __vfs_setlease(filp, arg, lease); |
1c8c601a | 1577 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1578 | |
1579 | return error; | |
1580 | } | |
a9933cea | 1581 | EXPORT_SYMBOL_GPL(vfs_setlease); |
1da177e4 | 1582 | |
0ceaf6c7 BF |
1583 | static int do_fcntl_delete_lease(struct file *filp) |
1584 | { | |
1585 | struct file_lock fl, *flp = &fl; | |
1586 | ||
1587 | lease_init(filp, F_UNLCK, flp); | |
1588 | ||
1589 | return vfs_setlease(filp, F_UNLCK, &flp); | |
1590 | } | |
1591 | ||
1592 | static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg) | |
1da177e4 | 1593 | { |
3df057ac | 1594 | struct file_lock *fl, *ret; |
1c8c601a | 1595 | struct inode *inode = file_inode(filp); |
f7347ce4 | 1596 | struct fasync_struct *new; |
1da177e4 LT |
1597 | int error; |
1598 | ||
c5b1f0d9 AB |
1599 | fl = lease_alloc(filp, arg); |
1600 | if (IS_ERR(fl)) | |
1601 | return PTR_ERR(fl); | |
1da177e4 | 1602 | |
f7347ce4 LT |
1603 | new = fasync_alloc(); |
1604 | if (!new) { | |
1605 | locks_free_lock(fl); | |
1606 | return -ENOMEM; | |
1607 | } | |
3df057ac | 1608 | ret = fl; |
1c8c601a | 1609 | spin_lock(&inode->i_lock); |
8896b93f | 1610 | error = __vfs_setlease(filp, arg, &ret); |
51ee4b84 | 1611 | if (error) { |
1c8c601a | 1612 | spin_unlock(&inode->i_lock); |
51ee4b84 CH |
1613 | locks_free_lock(fl); |
1614 | goto out_free_fasync; | |
1615 | } | |
3df057ac BF |
1616 | if (ret != fl) |
1617 | locks_free_lock(fl); | |
1da177e4 | 1618 | |
f7347ce4 LT |
1619 | /* |
1620 | * fasync_insert_entry() returns the old entry if any. | |
1621 | * If there was no old entry, then it used 'new' and | |
1622 | * inserted it into the fasync list. Clear new so that | |
1623 | * we don't release it here. | |
1624 | */ | |
3df057ac | 1625 | if (!fasync_insert_entry(fd, filp, &ret->fl_fasync, new)) |
f7347ce4 LT |
1626 | new = NULL; |
1627 | ||
8896b93f | 1628 | error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); |
1c8c601a | 1629 | spin_unlock(&inode->i_lock); |
51ee4b84 CH |
1630 | |
1631 | out_free_fasync: | |
f7347ce4 LT |
1632 | if (new) |
1633 | fasync_free(new); | |
1da177e4 LT |
1634 | return error; |
1635 | } | |
1636 | ||
0ceaf6c7 BF |
1637 | /** |
1638 | * fcntl_setlease - sets a lease on an open file | |
1639 | * @fd: open file descriptor | |
1640 | * @filp: file pointer | |
1641 | * @arg: type of lease to obtain | |
1642 | * | |
1643 | * Call this fcntl to establish a lease on the file. | |
1644 | * Note that you also need to call %F_SETSIG to | |
1645 | * receive a signal when the lease is broken. | |
1646 | */ | |
1647 | int fcntl_setlease(unsigned int fd, struct file *filp, long arg) | |
1648 | { | |
1649 | if (arg == F_UNLCK) | |
1650 | return do_fcntl_delete_lease(filp); | |
1651 | return do_fcntl_add_lease(fd, filp, arg); | |
1652 | } | |
1653 | ||
1da177e4 LT |
1654 | /** |
1655 | * flock_lock_file_wait - Apply a FLOCK-style lock to a file | |
1656 | * @filp: The file to apply the lock to | |
1657 | * @fl: The lock to be applied | |
1658 | * | |
1659 | * Add a FLOCK style lock to a file. | |
1660 | */ | |
1661 | int flock_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1662 | { | |
1663 | int error; | |
1664 | might_sleep(); | |
1665 | for (;;) { | |
1666 | error = flock_lock_file(filp, fl); | |
bde74e4b | 1667 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1668 | break; |
1669 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1670 | if (!error) | |
1671 | continue; | |
1672 | ||
1673 | locks_delete_block(fl); | |
1674 | break; | |
1675 | } | |
1676 | return error; | |
1677 | } | |
1678 | ||
1679 | EXPORT_SYMBOL(flock_lock_file_wait); | |
1680 | ||
1681 | /** | |
1682 | * sys_flock: - flock() system call. | |
1683 | * @fd: the file descriptor to lock. | |
1684 | * @cmd: the type of lock to apply. | |
1685 | * | |
1686 | * Apply a %FL_FLOCK style lock to an open file descriptor. | |
1687 | * The @cmd can be one of | |
1688 | * | |
1689 | * %LOCK_SH -- a shared lock. | |
1690 | * | |
1691 | * %LOCK_EX -- an exclusive lock. | |
1692 | * | |
1693 | * %LOCK_UN -- remove an existing lock. | |
1694 | * | |
1695 | * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes. | |
1696 | * | |
1697 | * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other | |
1698 | * processes read and write access respectively. | |
1699 | */ | |
002c8976 | 1700 | SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) |
1da177e4 | 1701 | { |
2903ff01 | 1702 | struct fd f = fdget(fd); |
1da177e4 LT |
1703 | struct file_lock *lock; |
1704 | int can_sleep, unlock; | |
1705 | int error; | |
1706 | ||
1707 | error = -EBADF; | |
2903ff01 | 1708 | if (!f.file) |
1da177e4 LT |
1709 | goto out; |
1710 | ||
1711 | can_sleep = !(cmd & LOCK_NB); | |
1712 | cmd &= ~LOCK_NB; | |
1713 | unlock = (cmd == LOCK_UN); | |
1714 | ||
aeb5d727 | 1715 | if (!unlock && !(cmd & LOCK_MAND) && |
2903ff01 | 1716 | !(f.file->f_mode & (FMODE_READ|FMODE_WRITE))) |
1da177e4 LT |
1717 | goto out_putf; |
1718 | ||
2903ff01 | 1719 | error = flock_make_lock(f.file, &lock, cmd); |
1da177e4 LT |
1720 | if (error) |
1721 | goto out_putf; | |
1722 | if (can_sleep) | |
1723 | lock->fl_flags |= FL_SLEEP; | |
1724 | ||
2903ff01 | 1725 | error = security_file_lock(f.file, lock->fl_type); |
1da177e4 LT |
1726 | if (error) |
1727 | goto out_free; | |
1728 | ||
2903ff01 AV |
1729 | if (f.file->f_op && f.file->f_op->flock) |
1730 | error = f.file->f_op->flock(f.file, | |
1da177e4 LT |
1731 | (can_sleep) ? F_SETLKW : F_SETLK, |
1732 | lock); | |
1733 | else | |
2903ff01 | 1734 | error = flock_lock_file_wait(f.file, lock); |
1da177e4 LT |
1735 | |
1736 | out_free: | |
993dfa87 | 1737 | locks_free_lock(lock); |
1da177e4 LT |
1738 | |
1739 | out_putf: | |
2903ff01 | 1740 | fdput(f); |
1da177e4 LT |
1741 | out: |
1742 | return error; | |
1743 | } | |
1744 | ||
3ee17abd BF |
1745 | /** |
1746 | * vfs_test_lock - test file byte range lock | |
1747 | * @filp: The file to test lock for | |
6924c554 | 1748 | * @fl: The lock to test; also used to hold result |
3ee17abd BF |
1749 | * |
1750 | * Returns -ERRNO on failure. Indicates presence of conflicting lock by | |
1751 | * setting conf->fl_type to something other than F_UNLCK. | |
1752 | */ | |
1753 | int vfs_test_lock(struct file *filp, struct file_lock *fl) | |
1754 | { | |
1755 | if (filp->f_op && filp->f_op->lock) | |
1756 | return filp->f_op->lock(filp, F_GETLK, fl); | |
1757 | posix_test_lock(filp, fl); | |
1758 | return 0; | |
1759 | } | |
1760 | EXPORT_SYMBOL_GPL(vfs_test_lock); | |
1761 | ||
c2fa1b8a BF |
1762 | static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) |
1763 | { | |
1764 | flock->l_pid = fl->fl_pid; | |
1765 | #if BITS_PER_LONG == 32 | |
1766 | /* | |
1767 | * Make sure we can represent the posix lock via | |
1768 | * legacy 32bit flock. | |
1769 | */ | |
1770 | if (fl->fl_start > OFFT_OFFSET_MAX) | |
1771 | return -EOVERFLOW; | |
1772 | if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX) | |
1773 | return -EOVERFLOW; | |
1774 | #endif | |
1775 | flock->l_start = fl->fl_start; | |
1776 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1777 | fl->fl_end - fl->fl_start + 1; | |
1778 | flock->l_whence = 0; | |
129a84de | 1779 | flock->l_type = fl->fl_type; |
c2fa1b8a BF |
1780 | return 0; |
1781 | } | |
1782 | ||
1783 | #if BITS_PER_LONG == 32 | |
1784 | static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) | |
1785 | { | |
1786 | flock->l_pid = fl->fl_pid; | |
1787 | flock->l_start = fl->fl_start; | |
1788 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1789 | fl->fl_end - fl->fl_start + 1; | |
1790 | flock->l_whence = 0; | |
1791 | flock->l_type = fl->fl_type; | |
1792 | } | |
1793 | #endif | |
1794 | ||
1da177e4 LT |
1795 | /* Report the first existing lock that would conflict with l. |
1796 | * This implements the F_GETLK command of fcntl(). | |
1797 | */ | |
1798 | int fcntl_getlk(struct file *filp, struct flock __user *l) | |
1799 | { | |
9d6a8c5c | 1800 | struct file_lock file_lock; |
1da177e4 LT |
1801 | struct flock flock; |
1802 | int error; | |
1803 | ||
1804 | error = -EFAULT; | |
1805 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1806 | goto out; | |
1807 | error = -EINVAL; | |
1808 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
1809 | goto out; | |
1810 | ||
1811 | error = flock_to_posix_lock(filp, &file_lock, &flock); | |
1812 | if (error) | |
1813 | goto out; | |
1814 | ||
3ee17abd BF |
1815 | error = vfs_test_lock(filp, &file_lock); |
1816 | if (error) | |
1817 | goto out; | |
1da177e4 | 1818 | |
9d6a8c5c ME |
1819 | flock.l_type = file_lock.fl_type; |
1820 | if (file_lock.fl_type != F_UNLCK) { | |
1821 | error = posix_lock_to_flock(&flock, &file_lock); | |
c2fa1b8a | 1822 | if (error) |
1da177e4 | 1823 | goto out; |
1da177e4 LT |
1824 | } |
1825 | error = -EFAULT; | |
1826 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
1827 | error = 0; | |
1828 | out: | |
1829 | return error; | |
1830 | } | |
1831 | ||
7723ec97 ME |
1832 | /** |
1833 | * vfs_lock_file - file byte range lock | |
1834 | * @filp: The file to apply the lock to | |
1835 | * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.) | |
1836 | * @fl: The lock to be applied | |
150b3934 ME |
1837 | * @conf: Place to return a copy of the conflicting lock, if found. |
1838 | * | |
1839 | * A caller that doesn't care about the conflicting lock may pass NULL | |
1840 | * as the final argument. | |
1841 | * | |
1842 | * If the filesystem defines a private ->lock() method, then @conf will | |
1843 | * be left unchanged; so a caller that cares should initialize it to | |
1844 | * some acceptable default. | |
2beb6614 ME |
1845 | * |
1846 | * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX | |
1847 | * locks, the ->lock() interface may return asynchronously, before the lock has | |
1848 | * been granted or denied by the underlying filesystem, if (and only if) | |
8fb47a4f | 1849 | * lm_grant is set. Callers expecting ->lock() to return asynchronously |
2beb6614 ME |
1850 | * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if) |
1851 | * the request is for a blocking lock. When ->lock() does return asynchronously, | |
8fb47a4f | 1852 | * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock |
2beb6614 ME |
1853 | * request completes. |
1854 | * If the request is for non-blocking lock the file system should return | |
bde74e4b MS |
1855 | * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine |
1856 | * with the result. If the request timed out the callback routine will return a | |
2beb6614 ME |
1857 | * nonzero return code and the file system should release the lock. The file |
1858 | * system is also responsible to keep a corresponding posix lock when it | |
1859 | * grants a lock so the VFS can find out which locks are locally held and do | |
1860 | * the correct lock cleanup when required. | |
1861 | * The underlying filesystem must not drop the kernel lock or call | |
8fb47a4f | 1862 | * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED |
2beb6614 | 1863 | * return code. |
7723ec97 | 1864 | */ |
150b3934 | 1865 | int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf) |
7723ec97 ME |
1866 | { |
1867 | if (filp->f_op && filp->f_op->lock) | |
1868 | return filp->f_op->lock(filp, cmd, fl); | |
1869 | else | |
150b3934 | 1870 | return posix_lock_file(filp, fl, conf); |
7723ec97 ME |
1871 | } |
1872 | EXPORT_SYMBOL_GPL(vfs_lock_file); | |
1873 | ||
b648a6de MS |
1874 | static int do_lock_file_wait(struct file *filp, unsigned int cmd, |
1875 | struct file_lock *fl) | |
1876 | { | |
1877 | int error; | |
1878 | ||
1879 | error = security_file_lock(filp, fl->fl_type); | |
1880 | if (error) | |
1881 | return error; | |
1882 | ||
764c76b3 MS |
1883 | for (;;) { |
1884 | error = vfs_lock_file(filp, cmd, fl, NULL); | |
1885 | if (error != FILE_LOCK_DEFERRED) | |
b648a6de | 1886 | break; |
764c76b3 MS |
1887 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); |
1888 | if (!error) | |
1889 | continue; | |
1890 | ||
1891 | locks_delete_block(fl); | |
1892 | break; | |
b648a6de MS |
1893 | } |
1894 | ||
1895 | return error; | |
1896 | } | |
1897 | ||
1da177e4 LT |
1898 | /* Apply the lock described by l to an open file descriptor. |
1899 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
1900 | */ | |
c293621b PS |
1901 | int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, |
1902 | struct flock __user *l) | |
1da177e4 LT |
1903 | { |
1904 | struct file_lock *file_lock = locks_alloc_lock(); | |
1905 | struct flock flock; | |
1906 | struct inode *inode; | |
0b2bac2f | 1907 | struct file *f; |
1da177e4 LT |
1908 | int error; |
1909 | ||
1910 | if (file_lock == NULL) | |
1911 | return -ENOLCK; | |
1912 | ||
1913 | /* | |
1914 | * This might block, so we do it before checking the inode. | |
1915 | */ | |
1916 | error = -EFAULT; | |
1917 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1918 | goto out; | |
1919 | ||
496ad9aa | 1920 | inode = file_inode(filp); |
1da177e4 LT |
1921 | |
1922 | /* Don't allow mandatory locks on files that may be memory mapped | |
1923 | * and shared. | |
1924 | */ | |
a16877ca | 1925 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
1926 | error = -EAGAIN; |
1927 | goto out; | |
1928 | } | |
1929 | ||
c293621b | 1930 | again: |
1da177e4 LT |
1931 | error = flock_to_posix_lock(filp, file_lock, &flock); |
1932 | if (error) | |
1933 | goto out; | |
1934 | if (cmd == F_SETLKW) { | |
1935 | file_lock->fl_flags |= FL_SLEEP; | |
1936 | } | |
1937 | ||
1938 | error = -EBADF; | |
1939 | switch (flock.l_type) { | |
1940 | case F_RDLCK: | |
1941 | if (!(filp->f_mode & FMODE_READ)) | |
1942 | goto out; | |
1943 | break; | |
1944 | case F_WRLCK: | |
1945 | if (!(filp->f_mode & FMODE_WRITE)) | |
1946 | goto out; | |
1947 | break; | |
1948 | case F_UNLCK: | |
1949 | break; | |
1950 | default: | |
1951 | error = -EINVAL; | |
1952 | goto out; | |
1953 | } | |
1954 | ||
b648a6de | 1955 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 1956 | |
c293621b PS |
1957 | /* |
1958 | * Attempt to detect a close/fcntl race and recover by | |
1959 | * releasing the lock that was just acquired. | |
1960 | */ | |
0b2bac2f AV |
1961 | /* |
1962 | * we need that spin_lock here - it prevents reordering between | |
1963 | * update of inode->i_flock and check for it done in close(). | |
1964 | * rcu_read_lock() wouldn't do. | |
1965 | */ | |
1966 | spin_lock(¤t->files->file_lock); | |
1967 | f = fcheck(fd); | |
1968 | spin_unlock(¤t->files->file_lock); | |
1969 | if (!error && f != filp && flock.l_type != F_UNLCK) { | |
c293621b PS |
1970 | flock.l_type = F_UNLCK; |
1971 | goto again; | |
1da177e4 LT |
1972 | } |
1973 | ||
c293621b | 1974 | out: |
1da177e4 LT |
1975 | locks_free_lock(file_lock); |
1976 | return error; | |
1977 | } | |
1978 | ||
1979 | #if BITS_PER_LONG == 32 | |
1980 | /* Report the first existing lock that would conflict with l. | |
1981 | * This implements the F_GETLK command of fcntl(). | |
1982 | */ | |
1983 | int fcntl_getlk64(struct file *filp, struct flock64 __user *l) | |
1984 | { | |
9d6a8c5c | 1985 | struct file_lock file_lock; |
1da177e4 LT |
1986 | struct flock64 flock; |
1987 | int error; | |
1988 | ||
1989 | error = -EFAULT; | |
1990 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1991 | goto out; | |
1992 | error = -EINVAL; | |
1993 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
1994 | goto out; | |
1995 | ||
1996 | error = flock64_to_posix_lock(filp, &file_lock, &flock); | |
1997 | if (error) | |
1998 | goto out; | |
1999 | ||
3ee17abd BF |
2000 | error = vfs_test_lock(filp, &file_lock); |
2001 | if (error) | |
2002 | goto out; | |
2003 | ||
9d6a8c5c ME |
2004 | flock.l_type = file_lock.fl_type; |
2005 | if (file_lock.fl_type != F_UNLCK) | |
2006 | posix_lock_to_flock64(&flock, &file_lock); | |
2007 | ||
1da177e4 LT |
2008 | error = -EFAULT; |
2009 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
2010 | error = 0; | |
2011 | ||
2012 | out: | |
2013 | return error; | |
2014 | } | |
2015 | ||
2016 | /* Apply the lock described by l to an open file descriptor. | |
2017 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2018 | */ | |
c293621b PS |
2019 | int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, |
2020 | struct flock64 __user *l) | |
1da177e4 LT |
2021 | { |
2022 | struct file_lock *file_lock = locks_alloc_lock(); | |
2023 | struct flock64 flock; | |
2024 | struct inode *inode; | |
0b2bac2f | 2025 | struct file *f; |
1da177e4 LT |
2026 | int error; |
2027 | ||
2028 | if (file_lock == NULL) | |
2029 | return -ENOLCK; | |
2030 | ||
2031 | /* | |
2032 | * This might block, so we do it before checking the inode. | |
2033 | */ | |
2034 | error = -EFAULT; | |
2035 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2036 | goto out; | |
2037 | ||
496ad9aa | 2038 | inode = file_inode(filp); |
1da177e4 LT |
2039 | |
2040 | /* Don't allow mandatory locks on files that may be memory mapped | |
2041 | * and shared. | |
2042 | */ | |
a16877ca | 2043 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
2044 | error = -EAGAIN; |
2045 | goto out; | |
2046 | } | |
2047 | ||
c293621b | 2048 | again: |
1da177e4 LT |
2049 | error = flock64_to_posix_lock(filp, file_lock, &flock); |
2050 | if (error) | |
2051 | goto out; | |
2052 | if (cmd == F_SETLKW64) { | |
2053 | file_lock->fl_flags |= FL_SLEEP; | |
2054 | } | |
2055 | ||
2056 | error = -EBADF; | |
2057 | switch (flock.l_type) { | |
2058 | case F_RDLCK: | |
2059 | if (!(filp->f_mode & FMODE_READ)) | |
2060 | goto out; | |
2061 | break; | |
2062 | case F_WRLCK: | |
2063 | if (!(filp->f_mode & FMODE_WRITE)) | |
2064 | goto out; | |
2065 | break; | |
2066 | case F_UNLCK: | |
2067 | break; | |
2068 | default: | |
2069 | error = -EINVAL; | |
2070 | goto out; | |
2071 | } | |
2072 | ||
b648a6de | 2073 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2074 | |
c293621b PS |
2075 | /* |
2076 | * Attempt to detect a close/fcntl race and recover by | |
2077 | * releasing the lock that was just acquired. | |
2078 | */ | |
0b2bac2f AV |
2079 | spin_lock(¤t->files->file_lock); |
2080 | f = fcheck(fd); | |
2081 | spin_unlock(¤t->files->file_lock); | |
2082 | if (!error && f != filp && flock.l_type != F_UNLCK) { | |
c293621b PS |
2083 | flock.l_type = F_UNLCK; |
2084 | goto again; | |
1da177e4 LT |
2085 | } |
2086 | ||
2087 | out: | |
2088 | locks_free_lock(file_lock); | |
2089 | return error; | |
2090 | } | |
2091 | #endif /* BITS_PER_LONG == 32 */ | |
2092 | ||
2093 | /* | |
2094 | * This function is called when the file is being removed | |
2095 | * from the task's fd array. POSIX locks belonging to this task | |
2096 | * are deleted at this time. | |
2097 | */ | |
2098 | void locks_remove_posix(struct file *filp, fl_owner_t owner) | |
2099 | { | |
ff7b86b8 | 2100 | struct file_lock lock; |
1da177e4 LT |
2101 | |
2102 | /* | |
2103 | * If there are no locks held on this file, we don't need to call | |
2104 | * posix_lock_file(). Another process could be setting a lock on this | |
2105 | * file at the same time, but we wouldn't remove that lock anyway. | |
2106 | */ | |
496ad9aa | 2107 | if (!file_inode(filp)->i_flock) |
1da177e4 LT |
2108 | return; |
2109 | ||
2110 | lock.fl_type = F_UNLCK; | |
75e1fcc0 | 2111 | lock.fl_flags = FL_POSIX | FL_CLOSE; |
1da177e4 LT |
2112 | lock.fl_start = 0; |
2113 | lock.fl_end = OFFSET_MAX; | |
2114 | lock.fl_owner = owner; | |
2115 | lock.fl_pid = current->tgid; | |
2116 | lock.fl_file = filp; | |
2117 | lock.fl_ops = NULL; | |
2118 | lock.fl_lmops = NULL; | |
2119 | ||
150b3934 | 2120 | vfs_lock_file(filp, F_SETLK, &lock, NULL); |
1da177e4 | 2121 | |
1da177e4 LT |
2122 | if (lock.fl_ops && lock.fl_ops->fl_release_private) |
2123 | lock.fl_ops->fl_release_private(&lock); | |
2124 | } | |
2125 | ||
2126 | EXPORT_SYMBOL(locks_remove_posix); | |
2127 | ||
2128 | /* | |
2129 | * This function is called on the last close of an open file. | |
2130 | */ | |
2131 | void locks_remove_flock(struct file *filp) | |
2132 | { | |
496ad9aa | 2133 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
2134 | struct file_lock *fl; |
2135 | struct file_lock **before; | |
2136 | ||
2137 | if (!inode->i_flock) | |
2138 | return; | |
2139 | ||
2140 | if (filp->f_op && filp->f_op->flock) { | |
2141 | struct file_lock fl = { | |
2142 | .fl_pid = current->tgid, | |
2143 | .fl_file = filp, | |
2144 | .fl_flags = FL_FLOCK, | |
2145 | .fl_type = F_UNLCK, | |
2146 | .fl_end = OFFSET_MAX, | |
2147 | }; | |
2148 | filp->f_op->flock(filp, F_SETLKW, &fl); | |
80fec4c6 TM |
2149 | if (fl.fl_ops && fl.fl_ops->fl_release_private) |
2150 | fl.fl_ops->fl_release_private(&fl); | |
1da177e4 LT |
2151 | } |
2152 | ||
1c8c601a | 2153 | spin_lock(&inode->i_lock); |
1da177e4 LT |
2154 | before = &inode->i_flock; |
2155 | ||
2156 | while ((fl = *before) != NULL) { | |
2157 | if (fl->fl_file == filp) { | |
c293621b | 2158 | if (IS_FLOCK(fl)) { |
1da177e4 LT |
2159 | locks_delete_lock(before); |
2160 | continue; | |
2161 | } | |
2162 | if (IS_LEASE(fl)) { | |
2163 | lease_modify(before, F_UNLCK); | |
2164 | continue; | |
2165 | } | |
2166 | /* What? */ | |
2167 | BUG(); | |
2168 | } | |
2169 | before = &fl->fl_next; | |
2170 | } | |
1c8c601a | 2171 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2172 | } |
2173 | ||
1da177e4 LT |
2174 | /** |
2175 | * posix_unblock_lock - stop waiting for a file lock | |
1da177e4 LT |
2176 | * @waiter: the lock which was waiting |
2177 | * | |
2178 | * lockd needs to block waiting for locks. | |
2179 | */ | |
64a318ee | 2180 | int |
f891a29f | 2181 | posix_unblock_lock(struct file_lock *waiter) |
1da177e4 | 2182 | { |
64a318ee BF |
2183 | int status = 0; |
2184 | ||
1c8c601a | 2185 | spin_lock(&file_lock_lock); |
5996a298 | 2186 | if (waiter->fl_next) |
1da177e4 | 2187 | __locks_delete_block(waiter); |
64a318ee BF |
2188 | else |
2189 | status = -ENOENT; | |
1c8c601a | 2190 | spin_unlock(&file_lock_lock); |
64a318ee | 2191 | return status; |
1da177e4 | 2192 | } |
1da177e4 LT |
2193 | EXPORT_SYMBOL(posix_unblock_lock); |
2194 | ||
9b9d2ab4 ME |
2195 | /** |
2196 | * vfs_cancel_lock - file byte range unblock lock | |
2197 | * @filp: The file to apply the unblock to | |
2198 | * @fl: The lock to be unblocked | |
2199 | * | |
2200 | * Used by lock managers to cancel blocked requests | |
2201 | */ | |
2202 | int vfs_cancel_lock(struct file *filp, struct file_lock *fl) | |
2203 | { | |
2204 | if (filp->f_op && filp->f_op->lock) | |
2205 | return filp->f_op->lock(filp, F_CANCELLK, fl); | |
2206 | return 0; | |
2207 | } | |
2208 | ||
2209 | EXPORT_SYMBOL_GPL(vfs_cancel_lock); | |
2210 | ||
7f8ada98 | 2211 | #ifdef CONFIG_PROC_FS |
d8ba7a36 | 2212 | #include <linux/proc_fs.h> |
7f8ada98 PE |
2213 | #include <linux/seq_file.h> |
2214 | ||
2215 | static void lock_get_status(struct seq_file *f, struct file_lock *fl, | |
99dc8292 | 2216 | loff_t id, char *pfx) |
1da177e4 LT |
2217 | { |
2218 | struct inode *inode = NULL; | |
ab1f1611 VG |
2219 | unsigned int fl_pid; |
2220 | ||
2221 | if (fl->fl_nspid) | |
6c5f3e7b | 2222 | fl_pid = pid_vnr(fl->fl_nspid); |
ab1f1611 VG |
2223 | else |
2224 | fl_pid = fl->fl_pid; | |
1da177e4 LT |
2225 | |
2226 | if (fl->fl_file != NULL) | |
496ad9aa | 2227 | inode = file_inode(fl->fl_file); |
1da177e4 | 2228 | |
99dc8292 | 2229 | seq_printf(f, "%lld:%s ", id, pfx); |
1da177e4 | 2230 | if (IS_POSIX(fl)) { |
7f8ada98 | 2231 | seq_printf(f, "%6s %s ", |
1da177e4 LT |
2232 | (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ", |
2233 | (inode == NULL) ? "*NOINODE*" : | |
a16877ca | 2234 | mandatory_lock(inode) ? "MANDATORY" : "ADVISORY "); |
1da177e4 LT |
2235 | } else if (IS_FLOCK(fl)) { |
2236 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2237 | seq_printf(f, "FLOCK MSNFS "); |
1da177e4 | 2238 | } else { |
7f8ada98 | 2239 | seq_printf(f, "FLOCK ADVISORY "); |
1da177e4 LT |
2240 | } |
2241 | } else if (IS_LEASE(fl)) { | |
7f8ada98 | 2242 | seq_printf(f, "LEASE "); |
ab83fa4b | 2243 | if (lease_breaking(fl)) |
7f8ada98 | 2244 | seq_printf(f, "BREAKING "); |
1da177e4 | 2245 | else if (fl->fl_file) |
7f8ada98 | 2246 | seq_printf(f, "ACTIVE "); |
1da177e4 | 2247 | else |
7f8ada98 | 2248 | seq_printf(f, "BREAKER "); |
1da177e4 | 2249 | } else { |
7f8ada98 | 2250 | seq_printf(f, "UNKNOWN UNKNOWN "); |
1da177e4 LT |
2251 | } |
2252 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2253 | seq_printf(f, "%s ", |
1da177e4 LT |
2254 | (fl->fl_type & LOCK_READ) |
2255 | ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ " | |
2256 | : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE "); | |
2257 | } else { | |
7f8ada98 | 2258 | seq_printf(f, "%s ", |
ab83fa4b | 2259 | (lease_breaking(fl)) |
0ee5c6d6 JL |
2260 | ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ " |
2261 | : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ "); | |
1da177e4 LT |
2262 | } |
2263 | if (inode) { | |
2264 | #ifdef WE_CAN_BREAK_LSLK_NOW | |
ab1f1611 | 2265 | seq_printf(f, "%d %s:%ld ", fl_pid, |
1da177e4 LT |
2266 | inode->i_sb->s_id, inode->i_ino); |
2267 | #else | |
2268 | /* userspace relies on this representation of dev_t ;-( */ | |
ab1f1611 | 2269 | seq_printf(f, "%d %02x:%02x:%ld ", fl_pid, |
1da177e4 LT |
2270 | MAJOR(inode->i_sb->s_dev), |
2271 | MINOR(inode->i_sb->s_dev), inode->i_ino); | |
2272 | #endif | |
2273 | } else { | |
ab1f1611 | 2274 | seq_printf(f, "%d <none>:0 ", fl_pid); |
1da177e4 LT |
2275 | } |
2276 | if (IS_POSIX(fl)) { | |
2277 | if (fl->fl_end == OFFSET_MAX) | |
7f8ada98 | 2278 | seq_printf(f, "%Ld EOF\n", fl->fl_start); |
1da177e4 | 2279 | else |
7f8ada98 | 2280 | seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end); |
1da177e4 | 2281 | } else { |
7f8ada98 | 2282 | seq_printf(f, "0 EOF\n"); |
1da177e4 LT |
2283 | } |
2284 | } | |
2285 | ||
7f8ada98 | 2286 | static int locks_show(struct seq_file *f, void *v) |
1da177e4 | 2287 | { |
7f8ada98 | 2288 | struct file_lock *fl, *bfl; |
1da177e4 | 2289 | |
7f8ada98 | 2290 | fl = list_entry(v, struct file_lock, fl_link); |
1da177e4 | 2291 | |
99dc8292 | 2292 | lock_get_status(f, fl, *((loff_t *)f->private), ""); |
1da177e4 | 2293 | |
7f8ada98 | 2294 | list_for_each_entry(bfl, &fl->fl_block, fl_block) |
99dc8292 | 2295 | lock_get_status(f, bfl, *((loff_t *)f->private), " ->"); |
094f2825 | 2296 | |
7f8ada98 PE |
2297 | return 0; |
2298 | } | |
1da177e4 | 2299 | |
7f8ada98 PE |
2300 | static void *locks_start(struct seq_file *f, loff_t *pos) |
2301 | { | |
99dc8292 JM |
2302 | loff_t *p = f->private; |
2303 | ||
1c8c601a | 2304 | spin_lock(&file_lock_lock); |
99dc8292 | 2305 | *p = (*pos + 1); |
7f8ada98 PE |
2306 | return seq_list_start(&file_lock_list, *pos); |
2307 | } | |
1da177e4 | 2308 | |
7f8ada98 PE |
2309 | static void *locks_next(struct seq_file *f, void *v, loff_t *pos) |
2310 | { | |
99dc8292 JM |
2311 | loff_t *p = f->private; |
2312 | ++*p; | |
7f8ada98 PE |
2313 | return seq_list_next(v, &file_lock_list, pos); |
2314 | } | |
1da177e4 | 2315 | |
7f8ada98 PE |
2316 | static void locks_stop(struct seq_file *f, void *v) |
2317 | { | |
1c8c601a | 2318 | spin_unlock(&file_lock_lock); |
1da177e4 LT |
2319 | } |
2320 | ||
d8ba7a36 | 2321 | static const struct seq_operations locks_seq_operations = { |
7f8ada98 PE |
2322 | .start = locks_start, |
2323 | .next = locks_next, | |
2324 | .stop = locks_stop, | |
2325 | .show = locks_show, | |
2326 | }; | |
d8ba7a36 AD |
2327 | |
2328 | static int locks_open(struct inode *inode, struct file *filp) | |
2329 | { | |
99dc8292 | 2330 | return seq_open_private(filp, &locks_seq_operations, sizeof(loff_t)); |
d8ba7a36 AD |
2331 | } |
2332 | ||
2333 | static const struct file_operations proc_locks_operations = { | |
2334 | .open = locks_open, | |
2335 | .read = seq_read, | |
2336 | .llseek = seq_lseek, | |
99dc8292 | 2337 | .release = seq_release_private, |
d8ba7a36 AD |
2338 | }; |
2339 | ||
2340 | static int __init proc_locks_init(void) | |
2341 | { | |
2342 | proc_create("locks", 0, NULL, &proc_locks_operations); | |
2343 | return 0; | |
2344 | } | |
2345 | module_init(proc_locks_init); | |
7f8ada98 PE |
2346 | #endif |
2347 | ||
1da177e4 LT |
2348 | /** |
2349 | * lock_may_read - checks that the region is free of locks | |
2350 | * @inode: the inode that is being read | |
2351 | * @start: the first byte to read | |
2352 | * @len: the number of bytes to read | |
2353 | * | |
2354 | * Emulates Windows locking requirements. Whole-file | |
2355 | * mandatory locks (share modes) can prohibit a read and | |
2356 | * byte-range POSIX locks can prohibit a read if they overlap. | |
2357 | * | |
2358 | * N.B. this function is only ever called | |
2359 | * from knfsd and ownership of locks is never checked. | |
2360 | */ | |
2361 | int lock_may_read(struct inode *inode, loff_t start, unsigned long len) | |
2362 | { | |
2363 | struct file_lock *fl; | |
2364 | int result = 1; | |
1c8c601a JL |
2365 | |
2366 | spin_lock(&inode->i_lock); | |
1da177e4 LT |
2367 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
2368 | if (IS_POSIX(fl)) { | |
2369 | if (fl->fl_type == F_RDLCK) | |
2370 | continue; | |
2371 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2372 | continue; | |
2373 | } else if (IS_FLOCK(fl)) { | |
2374 | if (!(fl->fl_type & LOCK_MAND)) | |
2375 | continue; | |
2376 | if (fl->fl_type & LOCK_READ) | |
2377 | continue; | |
2378 | } else | |
2379 | continue; | |
2380 | result = 0; | |
2381 | break; | |
2382 | } | |
1c8c601a | 2383 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2384 | return result; |
2385 | } | |
2386 | ||
2387 | EXPORT_SYMBOL(lock_may_read); | |
2388 | ||
2389 | /** | |
2390 | * lock_may_write - checks that the region is free of locks | |
2391 | * @inode: the inode that is being written | |
2392 | * @start: the first byte to write | |
2393 | * @len: the number of bytes to write | |
2394 | * | |
2395 | * Emulates Windows locking requirements. Whole-file | |
2396 | * mandatory locks (share modes) can prohibit a write and | |
2397 | * byte-range POSIX locks can prohibit a write if they overlap. | |
2398 | * | |
2399 | * N.B. this function is only ever called | |
2400 | * from knfsd and ownership of locks is never checked. | |
2401 | */ | |
2402 | int lock_may_write(struct inode *inode, loff_t start, unsigned long len) | |
2403 | { | |
2404 | struct file_lock *fl; | |
2405 | int result = 1; | |
1c8c601a JL |
2406 | |
2407 | spin_lock(&inode->i_lock); | |
1da177e4 LT |
2408 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
2409 | if (IS_POSIX(fl)) { | |
2410 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2411 | continue; | |
2412 | } else if (IS_FLOCK(fl)) { | |
2413 | if (!(fl->fl_type & LOCK_MAND)) | |
2414 | continue; | |
2415 | if (fl->fl_type & LOCK_WRITE) | |
2416 | continue; | |
2417 | } else | |
2418 | continue; | |
2419 | result = 0; | |
2420 | break; | |
2421 | } | |
1c8c601a | 2422 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2423 | return result; |
2424 | } | |
2425 | ||
2426 | EXPORT_SYMBOL(lock_may_write); | |
2427 | ||
1da177e4 LT |
2428 | static int __init filelock_init(void) |
2429 | { | |
2430 | filelock_cache = kmem_cache_create("file_lock_cache", | |
ee19cc40 MS |
2431 | sizeof(struct file_lock), 0, SLAB_PANIC, NULL); |
2432 | ||
1da177e4 LT |
2433 | return 0; |
2434 | } | |
2435 | ||
2436 | core_initcall(filelock_init); |