Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/locks.c | |
3 | * | |
4 | * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls. | |
5 | * Doug Evans (dje@spiff.uucp), August 07, 1992 | |
6 | * | |
7 | * Deadlock detection added. | |
8 | * FIXME: one thing isn't handled yet: | |
9 | * - mandatory locks (requires lots of changes elsewhere) | |
10 | * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994. | |
11 | * | |
12 | * Miscellaneous edits, and a total rewrite of posix_lock_file() code. | |
13 | * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994 | |
14 | * | |
15 | * Converted file_lock_table to a linked list from an array, which eliminates | |
16 | * the limits on how many active file locks are open. | |
17 | * Chad Page (pageone@netcom.com), November 27, 1994 | |
18 | * | |
19 | * Removed dependency on file descriptors. dup()'ed file descriptors now | |
20 | * get the same locks as the original file descriptors, and a close() on | |
21 | * any file descriptor removes ALL the locks on the file for the current | |
22 | * process. Since locks still depend on the process id, locks are inherited | |
23 | * after an exec() but not after a fork(). This agrees with POSIX, and both | |
24 | * BSD and SVR4 practice. | |
25 | * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995 | |
26 | * | |
27 | * Scrapped free list which is redundant now that we allocate locks | |
28 | * dynamically with kmalloc()/kfree(). | |
29 | * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995 | |
30 | * | |
31 | * Implemented two lock personalities - FL_FLOCK and FL_POSIX. | |
32 | * | |
33 | * FL_POSIX locks are created with calls to fcntl() and lockf() through the | |
34 | * fcntl() system call. They have the semantics described above. | |
35 | * | |
36 | * FL_FLOCK locks are created with calls to flock(), through the flock() | |
37 | * system call, which is new. Old C libraries implement flock() via fcntl() | |
38 | * and will continue to use the old, broken implementation. | |
39 | * | |
40 | * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated | |
41 | * with a file pointer (filp). As a result they can be shared by a parent | |
42 | * process and its children after a fork(). They are removed when the last | |
43 | * file descriptor referring to the file pointer is closed (unless explicitly | |
44 | * unlocked). | |
45 | * | |
46 | * FL_FLOCK locks never deadlock, an existing lock is always removed before | |
47 | * upgrading from shared to exclusive (or vice versa). When this happens | |
48 | * any processes blocked by the current lock are woken up and allowed to | |
49 | * run before the new lock is applied. | |
50 | * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995 | |
51 | * | |
52 | * Removed some race conditions in flock_lock_file(), marked other possible | |
53 | * races. Just grep for FIXME to see them. | |
54 | * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996. | |
55 | * | |
56 | * Addressed Dmitry's concerns. Deadlock checking no longer recursive. | |
57 | * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep | |
58 | * once we've checked for blocking and deadlocking. | |
59 | * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996. | |
60 | * | |
61 | * Initial implementation of mandatory locks. SunOS turned out to be | |
62 | * a rotten model, so I implemented the "obvious" semantics. | |
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> |
48f74186 | 129 | #include <linux/hashtable.h> |
7012b02a JL |
130 | #include <linux/percpu.h> |
131 | #include <linux/lglock.h> | |
1da177e4 | 132 | |
1da177e4 LT |
133 | #include <asm/uaccess.h> |
134 | ||
135 | #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX) | |
136 | #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK) | |
617588d5 | 137 | #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG)) |
1da177e4 | 138 | |
ab83fa4b BF |
139 | static bool lease_breaking(struct file_lock *fl) |
140 | { | |
778fc546 BF |
141 | return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING); |
142 | } | |
143 | ||
144 | static int target_leasetype(struct file_lock *fl) | |
145 | { | |
146 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
147 | return F_UNLCK; | |
148 | if (fl->fl_flags & FL_DOWNGRADE_PENDING) | |
149 | return F_RDLCK; | |
150 | return fl->fl_type; | |
ab83fa4b BF |
151 | } |
152 | ||
1da177e4 LT |
153 | int leases_enable = 1; |
154 | int lease_break_time = 45; | |
155 | ||
156 | #define for_each_lock(inode, lockp) \ | |
157 | for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) | |
158 | ||
1c8c601a | 159 | /* |
7012b02a JL |
160 | * The global file_lock_list is only used for displaying /proc/locks, so we |
161 | * keep a list on each CPU, with each list protected by its own spinlock via | |
162 | * the file_lock_lglock. Note that alterations to the list also require that | |
163 | * the relevant i_lock is held. | |
1c8c601a | 164 | */ |
7012b02a JL |
165 | DEFINE_STATIC_LGLOCK(file_lock_lglock); |
166 | static DEFINE_PER_CPU(struct hlist_head, file_lock_list); | |
88974691 | 167 | |
1c8c601a | 168 | /* |
48f74186 | 169 | * The blocked_hash is used to find POSIX lock loops for deadlock detection. |
7b2296af | 170 | * It is protected by blocked_lock_lock. |
48f74186 JL |
171 | * |
172 | * We hash locks by lockowner in order to optimize searching for the lock a | |
173 | * particular lockowner is waiting on. | |
174 | * | |
175 | * FIXME: make this value scale via some heuristic? We generally will want more | |
176 | * buckets when we have more lockowners holding locks, but that's a little | |
177 | * difficult to determine without knowing what the workload will look like. | |
1c8c601a | 178 | */ |
48f74186 JL |
179 | #define BLOCKED_HASH_BITS 7 |
180 | static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); | |
88974691 | 181 | |
1c8c601a | 182 | /* |
7b2296af JL |
183 | * This lock protects the blocked_hash. Generally, if you're accessing it, you |
184 | * want to be holding this lock. | |
1c8c601a JL |
185 | * |
186 | * In addition, it also protects the fl->fl_block list, and the fl->fl_next | |
187 | * pointer for file_lock structures that are acting as lock requests (in | |
188 | * contrast to those that are acting as records of acquired locks). | |
189 | * | |
190 | * Note that when we acquire this lock in order to change the above fields, | |
191 | * we often hold the i_lock as well. In certain cases, when reading the fields | |
192 | * protected by this lock, we can skip acquiring it iff we already hold the | |
193 | * i_lock. | |
194 | * | |
195 | * In particular, adding an entry to the fl_block list requires that you hold | |
196 | * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting | |
197 | * an entry from the list however only requires the file_lock_lock. | |
198 | */ | |
7b2296af | 199 | static DEFINE_SPINLOCK(blocked_lock_lock); |
1da177e4 | 200 | |
e18b890b | 201 | static struct kmem_cache *filelock_cache __read_mostly; |
1da177e4 | 202 | |
ee19cc40 | 203 | static void locks_init_lock_heads(struct file_lock *fl) |
a51cb91d | 204 | { |
139ca04e | 205 | INIT_HLIST_NODE(&fl->fl_link); |
ee19cc40 MS |
206 | INIT_LIST_HEAD(&fl->fl_block); |
207 | init_waitqueue_head(&fl->fl_wait); | |
a51cb91d MS |
208 | } |
209 | ||
1da177e4 | 210 | /* Allocate an empty lock structure. */ |
c5b1f0d9 | 211 | struct file_lock *locks_alloc_lock(void) |
1da177e4 | 212 | { |
ee19cc40 | 213 | struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL); |
a51cb91d MS |
214 | |
215 | if (fl) | |
ee19cc40 | 216 | locks_init_lock_heads(fl); |
a51cb91d MS |
217 | |
218 | return fl; | |
1da177e4 | 219 | } |
c5b1f0d9 | 220 | EXPORT_SYMBOL_GPL(locks_alloc_lock); |
1da177e4 | 221 | |
a9e61e25 | 222 | void locks_release_private(struct file_lock *fl) |
47831f35 TM |
223 | { |
224 | if (fl->fl_ops) { | |
225 | if (fl->fl_ops->fl_release_private) | |
226 | fl->fl_ops->fl_release_private(fl); | |
227 | fl->fl_ops = NULL; | |
228 | } | |
068535f1 | 229 | fl->fl_lmops = NULL; |
47831f35 TM |
230 | |
231 | } | |
a9e61e25 | 232 | EXPORT_SYMBOL_GPL(locks_release_private); |
47831f35 | 233 | |
1da177e4 | 234 | /* Free a lock which is not in use. */ |
05fa3135 | 235 | void locks_free_lock(struct file_lock *fl) |
1da177e4 | 236 | { |
5ce29646 MS |
237 | BUG_ON(waitqueue_active(&fl->fl_wait)); |
238 | BUG_ON(!list_empty(&fl->fl_block)); | |
139ca04e | 239 | BUG_ON(!hlist_unhashed(&fl->fl_link)); |
1da177e4 | 240 | |
47831f35 | 241 | locks_release_private(fl); |
1da177e4 LT |
242 | kmem_cache_free(filelock_cache, fl); |
243 | } | |
05fa3135 | 244 | EXPORT_SYMBOL(locks_free_lock); |
1da177e4 LT |
245 | |
246 | void locks_init_lock(struct file_lock *fl) | |
247 | { | |
ee19cc40 MS |
248 | memset(fl, 0, sizeof(struct file_lock)); |
249 | locks_init_lock_heads(fl); | |
1da177e4 LT |
250 | } |
251 | ||
252 | EXPORT_SYMBOL(locks_init_lock); | |
253 | ||
47831f35 TM |
254 | static void locks_copy_private(struct file_lock *new, struct file_lock *fl) |
255 | { | |
256 | if (fl->fl_ops) { | |
257 | if (fl->fl_ops->fl_copy_lock) | |
258 | fl->fl_ops->fl_copy_lock(new, fl); | |
259 | new->fl_ops = fl->fl_ops; | |
260 | } | |
bb8430a2 | 261 | if (fl->fl_lmops) |
47831f35 | 262 | new->fl_lmops = fl->fl_lmops; |
47831f35 TM |
263 | } |
264 | ||
1da177e4 LT |
265 | /* |
266 | * Initialize a new lock from an existing file_lock structure. | |
267 | */ | |
1a747ee0 | 268 | void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl) |
1da177e4 LT |
269 | { |
270 | new->fl_owner = fl->fl_owner; | |
271 | new->fl_pid = fl->fl_pid; | |
0996905f | 272 | new->fl_file = NULL; |
1da177e4 LT |
273 | new->fl_flags = fl->fl_flags; |
274 | new->fl_type = fl->fl_type; | |
275 | new->fl_start = fl->fl_start; | |
276 | new->fl_end = fl->fl_end; | |
0996905f TM |
277 | new->fl_ops = NULL; |
278 | new->fl_lmops = NULL; | |
279 | } | |
3dd7b71c | 280 | EXPORT_SYMBOL(__locks_copy_lock); |
0996905f TM |
281 | |
282 | void locks_copy_lock(struct file_lock *new, struct file_lock *fl) | |
283 | { | |
284 | locks_release_private(new); | |
285 | ||
286 | __locks_copy_lock(new, fl); | |
287 | new->fl_file = fl->fl_file; | |
1da177e4 LT |
288 | new->fl_ops = fl->fl_ops; |
289 | new->fl_lmops = fl->fl_lmops; | |
47831f35 TM |
290 | |
291 | locks_copy_private(new, fl); | |
1da177e4 LT |
292 | } |
293 | ||
294 | EXPORT_SYMBOL(locks_copy_lock); | |
295 | ||
296 | static inline int flock_translate_cmd(int cmd) { | |
297 | if (cmd & LOCK_MAND) | |
298 | return cmd & (LOCK_MAND | LOCK_RW); | |
299 | switch (cmd) { | |
300 | case LOCK_SH: | |
301 | return F_RDLCK; | |
302 | case LOCK_EX: | |
303 | return F_WRLCK; | |
304 | case LOCK_UN: | |
305 | return F_UNLCK; | |
306 | } | |
307 | return -EINVAL; | |
308 | } | |
309 | ||
310 | /* Fill in a file_lock structure with an appropriate FLOCK lock. */ | |
311 | static int flock_make_lock(struct file *filp, struct file_lock **lock, | |
312 | unsigned int cmd) | |
313 | { | |
314 | struct file_lock *fl; | |
315 | int type = flock_translate_cmd(cmd); | |
316 | if (type < 0) | |
317 | return type; | |
318 | ||
319 | fl = locks_alloc_lock(); | |
320 | if (fl == NULL) | |
321 | return -ENOMEM; | |
322 | ||
323 | fl->fl_file = filp; | |
324 | fl->fl_pid = current->tgid; | |
325 | fl->fl_flags = FL_FLOCK; | |
326 | fl->fl_type = type; | |
327 | fl->fl_end = OFFSET_MAX; | |
328 | ||
329 | *lock = fl; | |
330 | return 0; | |
331 | } | |
332 | ||
0ec4f431 | 333 | static int assign_type(struct file_lock *fl, long type) |
1da177e4 LT |
334 | { |
335 | switch (type) { | |
336 | case F_RDLCK: | |
337 | case F_WRLCK: | |
338 | case F_UNLCK: | |
339 | fl->fl_type = type; | |
340 | break; | |
341 | default: | |
342 | return -EINVAL; | |
343 | } | |
344 | return 0; | |
345 | } | |
346 | ||
ef12e72a BF |
347 | static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, |
348 | struct flock64 *l) | |
1da177e4 | 349 | { |
1da177e4 | 350 | switch (l->l_whence) { |
f5579f8c | 351 | case SEEK_SET: |
ef12e72a | 352 | fl->fl_start = 0; |
1da177e4 | 353 | break; |
f5579f8c | 354 | case SEEK_CUR: |
ef12e72a | 355 | fl->fl_start = filp->f_pos; |
1da177e4 | 356 | break; |
f5579f8c | 357 | case SEEK_END: |
ef12e72a | 358 | fl->fl_start = i_size_read(file_inode(filp)); |
1da177e4 LT |
359 | break; |
360 | default: | |
361 | return -EINVAL; | |
362 | } | |
ef12e72a BF |
363 | if (l->l_start > OFFSET_MAX - fl->fl_start) |
364 | return -EOVERFLOW; | |
365 | fl->fl_start += l->l_start; | |
366 | if (fl->fl_start < 0) | |
367 | return -EINVAL; | |
1da177e4 LT |
368 | |
369 | /* POSIX-1996 leaves the case l->l_len < 0 undefined; | |
370 | POSIX-2001 defines it. */ | |
4c780a46 | 371 | if (l->l_len > 0) { |
ef12e72a BF |
372 | if (l->l_len - 1 > OFFSET_MAX - fl->fl_start) |
373 | return -EOVERFLOW; | |
374 | fl->fl_end = fl->fl_start + l->l_len - 1; | |
375 | ||
4c780a46 | 376 | } else if (l->l_len < 0) { |
ef12e72a | 377 | if (fl->fl_start + l->l_len < 0) |
4c780a46 | 378 | return -EINVAL; |
ef12e72a BF |
379 | fl->fl_end = fl->fl_start - 1; |
380 | fl->fl_start += l->l_len; | |
381 | } else | |
382 | fl->fl_end = OFFSET_MAX; | |
383 | ||
1da177e4 LT |
384 | fl->fl_owner = current->files; |
385 | fl->fl_pid = current->tgid; | |
386 | fl->fl_file = filp; | |
387 | fl->fl_flags = FL_POSIX; | |
388 | fl->fl_ops = NULL; | |
389 | fl->fl_lmops = NULL; | |
390 | ||
bce7560d JL |
391 | /* Ensure that fl->fl_filp has compatible f_mode */ |
392 | switch (l->l_type) { | |
393 | case F_RDLCK: | |
394 | if (!(filp->f_mode & FMODE_READ)) | |
395 | return -EBADF; | |
396 | break; | |
397 | case F_WRLCK: | |
398 | if (!(filp->f_mode & FMODE_WRITE)) | |
399 | return -EBADF; | |
400 | break; | |
401 | } | |
402 | ||
1da177e4 LT |
403 | return assign_type(fl, l->l_type); |
404 | } | |
405 | ||
ef12e72a BF |
406 | /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX |
407 | * style lock. | |
408 | */ | |
409 | static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, | |
410 | struct flock *l) | |
1da177e4 | 411 | { |
ef12e72a BF |
412 | struct flock64 ll = { |
413 | .l_type = l->l_type, | |
414 | .l_whence = l->l_whence, | |
415 | .l_start = l->l_start, | |
416 | .l_len = l->l_len, | |
417 | }; | |
418 | ||
419 | return flock64_to_posix_lock(filp, fl, &ll); | |
1da177e4 | 420 | } |
1da177e4 LT |
421 | |
422 | /* default lease lock manager operations */ | |
423 | static void lease_break_callback(struct file_lock *fl) | |
424 | { | |
425 | kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG); | |
426 | } | |
427 | ||
7b021967 | 428 | static const struct lock_manager_operations lease_manager_ops = { |
8fb47a4f | 429 | .lm_break = lease_break_callback, |
8fb47a4f | 430 | .lm_change = lease_modify, |
1da177e4 LT |
431 | }; |
432 | ||
433 | /* | |
434 | * Initialize a lease, use the default lock manager operations | |
435 | */ | |
0ec4f431 | 436 | static int lease_init(struct file *filp, long type, struct file_lock *fl) |
1da177e4 | 437 | { |
75dff55a TM |
438 | if (assign_type(fl, type) != 0) |
439 | return -EINVAL; | |
440 | ||
1da177e4 LT |
441 | fl->fl_owner = current->files; |
442 | fl->fl_pid = current->tgid; | |
443 | ||
444 | fl->fl_file = filp; | |
445 | fl->fl_flags = FL_LEASE; | |
1da177e4 LT |
446 | fl->fl_start = 0; |
447 | fl->fl_end = OFFSET_MAX; | |
448 | fl->fl_ops = NULL; | |
449 | fl->fl_lmops = &lease_manager_ops; | |
450 | return 0; | |
451 | } | |
452 | ||
453 | /* Allocate a file_lock initialised to this type of lease */ | |
0ec4f431 | 454 | static struct file_lock *lease_alloc(struct file *filp, long type) |
1da177e4 LT |
455 | { |
456 | struct file_lock *fl = locks_alloc_lock(); | |
75dff55a | 457 | int error = -ENOMEM; |
1da177e4 LT |
458 | |
459 | if (fl == NULL) | |
e32b8ee2 | 460 | return ERR_PTR(error); |
1da177e4 LT |
461 | |
462 | error = lease_init(filp, type, fl); | |
75dff55a TM |
463 | if (error) { |
464 | locks_free_lock(fl); | |
e32b8ee2 | 465 | return ERR_PTR(error); |
75dff55a | 466 | } |
e32b8ee2 | 467 | return fl; |
1da177e4 LT |
468 | } |
469 | ||
470 | /* Check if two locks overlap each other. | |
471 | */ | |
472 | static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2) | |
473 | { | |
474 | return ((fl1->fl_end >= fl2->fl_start) && | |
475 | (fl2->fl_end >= fl1->fl_start)); | |
476 | } | |
477 | ||
478 | /* | |
479 | * Check whether two locks have the same owner. | |
480 | */ | |
33443c42 | 481 | static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) |
1da177e4 | 482 | { |
8fb47a4f | 483 | if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner) |
1da177e4 | 484 | return fl2->fl_lmops == fl1->fl_lmops && |
8fb47a4f | 485 | fl1->fl_lmops->lm_compare_owner(fl1, fl2); |
1da177e4 LT |
486 | return fl1->fl_owner == fl2->fl_owner; |
487 | } | |
488 | ||
7012b02a | 489 | /* Must be called with the i_lock held! */ |
6ca10ed8 | 490 | static void locks_insert_global_locks(struct file_lock *fl) |
88974691 | 491 | { |
7012b02a JL |
492 | lg_local_lock(&file_lock_lglock); |
493 | fl->fl_link_cpu = smp_processor_id(); | |
494 | hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list)); | |
495 | lg_local_unlock(&file_lock_lglock); | |
88974691 JL |
496 | } |
497 | ||
7012b02a | 498 | /* Must be called with the i_lock held! */ |
6ca10ed8 | 499 | static void locks_delete_global_locks(struct file_lock *fl) |
88974691 | 500 | { |
7012b02a JL |
501 | /* |
502 | * Avoid taking lock if already unhashed. This is safe since this check | |
503 | * is done while holding the i_lock, and new insertions into the list | |
504 | * also require that it be held. | |
505 | */ | |
506 | if (hlist_unhashed(&fl->fl_link)) | |
507 | return; | |
508 | lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu); | |
139ca04e | 509 | hlist_del_init(&fl->fl_link); |
7012b02a | 510 | lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu); |
88974691 JL |
511 | } |
512 | ||
3999e493 JL |
513 | static unsigned long |
514 | posix_owner_key(struct file_lock *fl) | |
515 | { | |
516 | if (fl->fl_lmops && fl->fl_lmops->lm_owner_key) | |
517 | return fl->fl_lmops->lm_owner_key(fl); | |
518 | return (unsigned long)fl->fl_owner; | |
519 | } | |
520 | ||
6ca10ed8 | 521 | static void locks_insert_global_blocked(struct file_lock *waiter) |
88974691 | 522 | { |
3999e493 | 523 | hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter)); |
88974691 JL |
524 | } |
525 | ||
6ca10ed8 | 526 | static void locks_delete_global_blocked(struct file_lock *waiter) |
88974691 | 527 | { |
48f74186 | 528 | hash_del(&waiter->fl_link); |
88974691 JL |
529 | } |
530 | ||
1da177e4 LT |
531 | /* Remove waiter from blocker's block list. |
532 | * When blocker ends up pointing to itself then the list is empty. | |
1c8c601a | 533 | * |
7b2296af | 534 | * Must be called with blocked_lock_lock held. |
1da177e4 | 535 | */ |
33443c42 | 536 | static void __locks_delete_block(struct file_lock *waiter) |
1da177e4 | 537 | { |
88974691 | 538 | locks_delete_global_blocked(waiter); |
1da177e4 | 539 | list_del_init(&waiter->fl_block); |
1da177e4 LT |
540 | waiter->fl_next = NULL; |
541 | } | |
542 | ||
1a9e64a7 | 543 | static void locks_delete_block(struct file_lock *waiter) |
1da177e4 | 544 | { |
7b2296af | 545 | spin_lock(&blocked_lock_lock); |
1da177e4 | 546 | __locks_delete_block(waiter); |
7b2296af | 547 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
548 | } |
549 | ||
550 | /* Insert waiter into blocker's block list. | |
551 | * We use a circular list so that processes can be easily woken up in | |
552 | * the order they blocked. The documentation doesn't require this but | |
553 | * it seems like the reasonable thing to do. | |
1c8c601a | 554 | * |
7b2296af | 555 | * Must be called with both the i_lock and blocked_lock_lock held. The fl_block |
46dad760 | 556 | * list itself is protected by the blocked_lock_lock, but by ensuring that the |
7b2296af | 557 | * i_lock is also held on insertions we can avoid taking the blocked_lock_lock |
4e8c765d | 558 | * in some cases when we see that the fl_block list is empty. |
1da177e4 | 559 | */ |
1c8c601a JL |
560 | static void __locks_insert_block(struct file_lock *blocker, |
561 | struct file_lock *waiter) | |
1da177e4 | 562 | { |
6dc0fe8f | 563 | BUG_ON(!list_empty(&waiter->fl_block)); |
1da177e4 | 564 | waiter->fl_next = blocker; |
88974691 | 565 | list_add_tail(&waiter->fl_block, &blocker->fl_block); |
1da177e4 | 566 | if (IS_POSIX(blocker)) |
1c8c601a JL |
567 | locks_insert_global_blocked(waiter); |
568 | } | |
569 | ||
570 | /* Must be called with i_lock held. */ | |
571 | static void locks_insert_block(struct file_lock *blocker, | |
572 | struct file_lock *waiter) | |
573 | { | |
7b2296af | 574 | spin_lock(&blocked_lock_lock); |
1c8c601a | 575 | __locks_insert_block(blocker, waiter); |
7b2296af | 576 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
577 | } |
578 | ||
1cb36012 JL |
579 | /* |
580 | * Wake up processes blocked waiting for blocker. | |
581 | * | |
1c8c601a | 582 | * Must be called with the inode->i_lock held! |
1da177e4 LT |
583 | */ |
584 | static void locks_wake_up_blocks(struct file_lock *blocker) | |
585 | { | |
4e8c765d JL |
586 | /* |
587 | * Avoid taking global lock if list is empty. This is safe since new | |
588 | * blocked requests are only added to the list under the i_lock, and | |
589 | * the i_lock is always held here. Note that removal from the fl_block | |
590 | * list does not require the i_lock, so we must recheck list_empty() | |
7b2296af | 591 | * after acquiring the blocked_lock_lock. |
4e8c765d JL |
592 | */ |
593 | if (list_empty(&blocker->fl_block)) | |
594 | return; | |
595 | ||
7b2296af | 596 | spin_lock(&blocked_lock_lock); |
1da177e4 | 597 | while (!list_empty(&blocker->fl_block)) { |
f0c1cd0e PE |
598 | struct file_lock *waiter; |
599 | ||
600 | waiter = list_first_entry(&blocker->fl_block, | |
1da177e4 LT |
601 | struct file_lock, fl_block); |
602 | __locks_delete_block(waiter); | |
8fb47a4f BF |
603 | if (waiter->fl_lmops && waiter->fl_lmops->lm_notify) |
604 | waiter->fl_lmops->lm_notify(waiter); | |
1da177e4 LT |
605 | else |
606 | wake_up(&waiter->fl_wait); | |
607 | } | |
7b2296af | 608 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
609 | } |
610 | ||
611 | /* Insert file lock fl into an inode's lock list at the position indicated | |
612 | * by pos. At the same time add the lock to the global file lock list. | |
1c8c601a JL |
613 | * |
614 | * Must be called with the i_lock held! | |
1da177e4 LT |
615 | */ |
616 | static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl) | |
617 | { | |
ab1f1611 VG |
618 | fl->fl_nspid = get_pid(task_tgid(current)); |
619 | ||
1da177e4 LT |
620 | /* insert into file's list */ |
621 | fl->fl_next = *pos; | |
622 | *pos = fl; | |
88974691 JL |
623 | |
624 | locks_insert_global_locks(fl); | |
1da177e4 LT |
625 | } |
626 | ||
24cbe784 JL |
627 | /** |
628 | * locks_delete_lock - Delete a lock and then free it. | |
629 | * @thisfl_p: pointer that points to the fl_next field of the previous | |
630 | * inode->i_flock list entry | |
631 | * | |
632 | * Unlink a lock from all lists and free the namespace reference, but don't | |
633 | * free it yet. Wake up processes that are blocked waiting for this lock and | |
634 | * notify the FS that the lock has been cleared. | |
1c8c601a JL |
635 | * |
636 | * Must be called with the i_lock held! | |
1da177e4 | 637 | */ |
24cbe784 | 638 | static void locks_unlink_lock(struct file_lock **thisfl_p) |
1da177e4 LT |
639 | { |
640 | struct file_lock *fl = *thisfl_p; | |
641 | ||
88974691 JL |
642 | locks_delete_global_locks(fl); |
643 | ||
1da177e4 LT |
644 | *thisfl_p = fl->fl_next; |
645 | fl->fl_next = NULL; | |
1da177e4 | 646 | |
ab1f1611 VG |
647 | if (fl->fl_nspid) { |
648 | put_pid(fl->fl_nspid); | |
649 | fl->fl_nspid = NULL; | |
650 | } | |
651 | ||
1da177e4 | 652 | locks_wake_up_blocks(fl); |
24cbe784 JL |
653 | } |
654 | ||
655 | /* | |
656 | * Unlink a lock from all lists and free it. | |
657 | * | |
658 | * Must be called with i_lock held! | |
659 | */ | |
660 | static void locks_delete_lock(struct file_lock **thisfl_p) | |
661 | { | |
662 | struct file_lock *fl = *thisfl_p; | |
663 | ||
664 | locks_unlink_lock(thisfl_p); | |
1da177e4 LT |
665 | locks_free_lock(fl); |
666 | } | |
667 | ||
668 | /* Determine if lock sys_fl blocks lock caller_fl. Common functionality | |
669 | * checks for shared/exclusive status of overlapping locks. | |
670 | */ | |
671 | static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
672 | { | |
673 | if (sys_fl->fl_type == F_WRLCK) | |
674 | return 1; | |
675 | if (caller_fl->fl_type == F_WRLCK) | |
676 | return 1; | |
677 | return 0; | |
678 | } | |
679 | ||
680 | /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific | |
681 | * checking before calling the locks_conflict(). | |
682 | */ | |
683 | static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
684 | { | |
685 | /* POSIX locks owned by the same process do not conflict with | |
686 | * each other. | |
687 | */ | |
688 | if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl)) | |
689 | return (0); | |
690 | ||
691 | /* Check whether they overlap */ | |
692 | if (!locks_overlap(caller_fl, sys_fl)) | |
693 | return 0; | |
694 | ||
695 | return (locks_conflict(caller_fl, sys_fl)); | |
696 | } | |
697 | ||
698 | /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific | |
699 | * checking before calling the locks_conflict(). | |
700 | */ | |
701 | static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
702 | { | |
703 | /* FLOCK locks referring to the same filp do not conflict with | |
704 | * each other. | |
705 | */ | |
706 | if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file)) | |
707 | return (0); | |
708 | if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND)) | |
709 | return 0; | |
710 | ||
711 | return (locks_conflict(caller_fl, sys_fl)); | |
712 | } | |
713 | ||
6d34ac19 | 714 | void |
9d6a8c5c | 715 | posix_test_lock(struct file *filp, struct file_lock *fl) |
1da177e4 LT |
716 | { |
717 | struct file_lock *cfl; | |
1c8c601a | 718 | struct inode *inode = file_inode(filp); |
1da177e4 | 719 | |
1c8c601a | 720 | spin_lock(&inode->i_lock); |
496ad9aa | 721 | for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) { |
1da177e4 LT |
722 | if (!IS_POSIX(cfl)) |
723 | continue; | |
b842e240 | 724 | if (posix_locks_conflict(fl, cfl)) |
1da177e4 LT |
725 | break; |
726 | } | |
ab1f1611 | 727 | if (cfl) { |
9d6a8c5c | 728 | __locks_copy_lock(fl, cfl); |
ab1f1611 | 729 | if (cfl->fl_nspid) |
6c5f3e7b | 730 | fl->fl_pid = pid_vnr(cfl->fl_nspid); |
ab1f1611 | 731 | } else |
129a84de | 732 | fl->fl_type = F_UNLCK; |
1c8c601a | 733 | spin_unlock(&inode->i_lock); |
6d34ac19 | 734 | return; |
1da177e4 | 735 | } |
1da177e4 LT |
736 | EXPORT_SYMBOL(posix_test_lock); |
737 | ||
b533184f BF |
738 | /* |
739 | * Deadlock detection: | |
740 | * | |
741 | * We attempt to detect deadlocks that are due purely to posix file | |
742 | * locks. | |
1da177e4 | 743 | * |
b533184f BF |
744 | * We assume that a task can be waiting for at most one lock at a time. |
745 | * So for any acquired lock, the process holding that lock may be | |
746 | * waiting on at most one other lock. That lock in turns may be held by | |
747 | * someone waiting for at most one other lock. Given a requested lock | |
748 | * caller_fl which is about to wait for a conflicting lock block_fl, we | |
749 | * follow this chain of waiters to ensure we are not about to create a | |
750 | * cycle. | |
1da177e4 | 751 | * |
b533184f BF |
752 | * Since we do this before we ever put a process to sleep on a lock, we |
753 | * are ensured that there is never a cycle; that is what guarantees that | |
754 | * the while() loop in posix_locks_deadlock() eventually completes. | |
97855b49 | 755 | * |
b533184f BF |
756 | * Note: the above assumption may not be true when handling lock |
757 | * requests from a broken NFS client. It may also fail in the presence | |
758 | * of tasks (such as posix threads) sharing the same open file table. | |
759 | * | |
760 | * To handle those cases, we just bail out after a few iterations. | |
1da177e4 | 761 | */ |
97855b49 BF |
762 | |
763 | #define MAX_DEADLK_ITERATIONS 10 | |
764 | ||
b533184f BF |
765 | /* Find a lock that the owner of the given block_fl is blocking on. */ |
766 | static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) | |
767 | { | |
768 | struct file_lock *fl; | |
769 | ||
3999e493 | 770 | hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) { |
b533184f BF |
771 | if (posix_same_owner(fl, block_fl)) |
772 | return fl->fl_next; | |
773 | } | |
774 | return NULL; | |
775 | } | |
776 | ||
7b2296af | 777 | /* Must be called with the blocked_lock_lock held! */ |
b0904e14 | 778 | static int posix_locks_deadlock(struct file_lock *caller_fl, |
1da177e4 LT |
779 | struct file_lock *block_fl) |
780 | { | |
97855b49 | 781 | int i = 0; |
1da177e4 | 782 | |
b533184f BF |
783 | while ((block_fl = what_owner_is_waiting_for(block_fl))) { |
784 | if (i++ > MAX_DEADLK_ITERATIONS) | |
785 | return 0; | |
786 | if (posix_same_owner(caller_fl, block_fl)) | |
787 | return 1; | |
1da177e4 LT |
788 | } |
789 | return 0; | |
790 | } | |
791 | ||
1da177e4 | 792 | /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks |
02888f41 | 793 | * after any leases, but before any posix locks. |
f475ae95 TM |
794 | * |
795 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
796 | * whether or not a lock was successfully freed by testing the return | |
797 | * value for -ENOENT. | |
1da177e4 | 798 | */ |
993dfa87 | 799 | static int flock_lock_file(struct file *filp, struct file_lock *request) |
1da177e4 | 800 | { |
993dfa87 | 801 | struct file_lock *new_fl = NULL; |
1da177e4 | 802 | struct file_lock **before; |
496ad9aa | 803 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
804 | int error = 0; |
805 | int found = 0; | |
806 | ||
b89f4321 | 807 | if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) { |
84d535ad | 808 | new_fl = locks_alloc_lock(); |
b89f4321 AB |
809 | if (!new_fl) |
810 | return -ENOMEM; | |
84d535ad PE |
811 | } |
812 | ||
1c8c601a | 813 | spin_lock(&inode->i_lock); |
b89f4321 AB |
814 | if (request->fl_flags & FL_ACCESS) |
815 | goto find_conflict; | |
816 | ||
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; | |
823 | if (filp != fl->fl_file) | |
824 | continue; | |
993dfa87 | 825 | if (request->fl_type == fl->fl_type) |
1da177e4 LT |
826 | goto out; |
827 | found = 1; | |
828 | locks_delete_lock(before); | |
829 | break; | |
830 | } | |
1da177e4 | 831 | |
f475ae95 TM |
832 | if (request->fl_type == F_UNLCK) { |
833 | if ((request->fl_flags & FL_EXISTS) && !found) | |
834 | error = -ENOENT; | |
993dfa87 | 835 | goto out; |
f475ae95 | 836 | } |
1da177e4 LT |
837 | |
838 | /* | |
839 | * If a higher-priority process was blocked on the old file lock, | |
840 | * give it the opportunity to lock the file. | |
841 | */ | |
b89f4321 | 842 | if (found) { |
1c8c601a | 843 | spin_unlock(&inode->i_lock); |
def01bc5 | 844 | cond_resched(); |
1c8c601a | 845 | spin_lock(&inode->i_lock); |
b89f4321 | 846 | } |
1da177e4 | 847 | |
f07f18dd | 848 | find_conflict: |
1da177e4 LT |
849 | for_each_lock(inode, before) { |
850 | struct file_lock *fl = *before; | |
851 | if (IS_POSIX(fl)) | |
852 | break; | |
853 | if (IS_LEASE(fl)) | |
854 | continue; | |
993dfa87 | 855 | if (!flock_locks_conflict(request, fl)) |
1da177e4 LT |
856 | continue; |
857 | error = -EAGAIN; | |
bde74e4b MS |
858 | if (!(request->fl_flags & FL_SLEEP)) |
859 | goto out; | |
860 | error = FILE_LOCK_DEFERRED; | |
861 | locks_insert_block(fl, request); | |
1da177e4 LT |
862 | goto out; |
863 | } | |
f07f18dd TM |
864 | if (request->fl_flags & FL_ACCESS) |
865 | goto out; | |
993dfa87 | 866 | locks_copy_lock(new_fl, request); |
0e2f6db8 | 867 | locks_insert_lock(before, new_fl); |
993dfa87 | 868 | new_fl = NULL; |
9cedc194 | 869 | error = 0; |
1da177e4 LT |
870 | |
871 | out: | |
1c8c601a | 872 | spin_unlock(&inode->i_lock); |
993dfa87 TM |
873 | if (new_fl) |
874 | locks_free_lock(new_fl); | |
1da177e4 LT |
875 | return error; |
876 | } | |
877 | ||
150b3934 | 878 | static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock) |
1da177e4 LT |
879 | { |
880 | struct file_lock *fl; | |
39005d02 MS |
881 | struct file_lock *new_fl = NULL; |
882 | struct file_lock *new_fl2 = NULL; | |
1da177e4 LT |
883 | struct file_lock *left = NULL; |
884 | struct file_lock *right = NULL; | |
885 | struct file_lock **before; | |
b9746ef8 JL |
886 | int error; |
887 | bool added = false; | |
1da177e4 LT |
888 | |
889 | /* | |
890 | * We may need two file_lock structures for this operation, | |
891 | * so we get them in advance to avoid races. | |
39005d02 MS |
892 | * |
893 | * In some cases we can be sure, that no new locks will be needed | |
1da177e4 | 894 | */ |
39005d02 MS |
895 | if (!(request->fl_flags & FL_ACCESS) && |
896 | (request->fl_type != F_UNLCK || | |
897 | request->fl_start != 0 || request->fl_end != OFFSET_MAX)) { | |
898 | new_fl = locks_alloc_lock(); | |
899 | new_fl2 = locks_alloc_lock(); | |
900 | } | |
1da177e4 | 901 | |
1c8c601a | 902 | spin_lock(&inode->i_lock); |
1cb36012 JL |
903 | /* |
904 | * New lock request. Walk all POSIX locks and look for conflicts. If | |
905 | * there are any, either return error or put the request on the | |
48f74186 | 906 | * blocker's list of waiters and the global blocked_hash. |
1cb36012 | 907 | */ |
1da177e4 LT |
908 | if (request->fl_type != F_UNLCK) { |
909 | for_each_lock(inode, before) { | |
526985b9 | 910 | fl = *before; |
1da177e4 LT |
911 | if (!IS_POSIX(fl)) |
912 | continue; | |
913 | if (!posix_locks_conflict(request, fl)) | |
914 | continue; | |
5842add2 | 915 | if (conflock) |
1a747ee0 | 916 | __locks_copy_lock(conflock, fl); |
1da177e4 LT |
917 | error = -EAGAIN; |
918 | if (!(request->fl_flags & FL_SLEEP)) | |
919 | goto out; | |
1c8c601a JL |
920 | /* |
921 | * Deadlock detection and insertion into the blocked | |
922 | * locks list must be done while holding the same lock! | |
923 | */ | |
1da177e4 | 924 | error = -EDEADLK; |
7b2296af | 925 | spin_lock(&blocked_lock_lock); |
1c8c601a JL |
926 | if (likely(!posix_locks_deadlock(request, fl))) { |
927 | error = FILE_LOCK_DEFERRED; | |
928 | __locks_insert_block(fl, request); | |
929 | } | |
7b2296af | 930 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
931 | goto out; |
932 | } | |
933 | } | |
934 | ||
935 | /* If we're just looking for a conflict, we're done. */ | |
936 | error = 0; | |
937 | if (request->fl_flags & FL_ACCESS) | |
938 | goto out; | |
939 | ||
1da177e4 | 940 | /* |
1da177e4 LT |
941 | * Find the first old lock with the same owner as the new lock. |
942 | */ | |
943 | ||
944 | before = &inode->i_flock; | |
945 | ||
946 | /* First skip locks owned by other processes. */ | |
947 | while ((fl = *before) && (!IS_POSIX(fl) || | |
948 | !posix_same_owner(request, fl))) { | |
949 | before = &fl->fl_next; | |
950 | } | |
951 | ||
1cb36012 | 952 | /* Process locks with this owner. */ |
1da177e4 LT |
953 | while ((fl = *before) && posix_same_owner(request, fl)) { |
954 | /* Detect adjacent or overlapping regions (if same lock type) | |
955 | */ | |
956 | if (request->fl_type == fl->fl_type) { | |
449231d6 OK |
957 | /* In all comparisons of start vs end, use |
958 | * "start - 1" rather than "end + 1". If end | |
959 | * is OFFSET_MAX, end + 1 will become negative. | |
960 | */ | |
1da177e4 LT |
961 | if (fl->fl_end < request->fl_start - 1) |
962 | goto next_lock; | |
963 | /* If the next lock in the list has entirely bigger | |
964 | * addresses than the new one, insert the lock here. | |
965 | */ | |
449231d6 | 966 | if (fl->fl_start - 1 > request->fl_end) |
1da177e4 LT |
967 | break; |
968 | ||
969 | /* If we come here, the new and old lock are of the | |
970 | * same type and adjacent or overlapping. Make one | |
971 | * lock yielding from the lower start address of both | |
972 | * locks to the higher end address. | |
973 | */ | |
974 | if (fl->fl_start > request->fl_start) | |
975 | fl->fl_start = request->fl_start; | |
976 | else | |
977 | request->fl_start = fl->fl_start; | |
978 | if (fl->fl_end < request->fl_end) | |
979 | fl->fl_end = request->fl_end; | |
980 | else | |
981 | request->fl_end = fl->fl_end; | |
982 | if (added) { | |
983 | locks_delete_lock(before); | |
984 | continue; | |
985 | } | |
986 | request = fl; | |
b9746ef8 | 987 | added = true; |
1da177e4 LT |
988 | } |
989 | else { | |
990 | /* Processing for different lock types is a bit | |
991 | * more complex. | |
992 | */ | |
993 | if (fl->fl_end < request->fl_start) | |
994 | goto next_lock; | |
995 | if (fl->fl_start > request->fl_end) | |
996 | break; | |
997 | if (request->fl_type == F_UNLCK) | |
b9746ef8 | 998 | added = true; |
1da177e4 LT |
999 | if (fl->fl_start < request->fl_start) |
1000 | left = fl; | |
1001 | /* If the next lock in the list has a higher end | |
1002 | * address than the new one, insert the new one here. | |
1003 | */ | |
1004 | if (fl->fl_end > request->fl_end) { | |
1005 | right = fl; | |
1006 | break; | |
1007 | } | |
1008 | if (fl->fl_start >= request->fl_start) { | |
1009 | /* The new lock completely replaces an old | |
1010 | * one (This may happen several times). | |
1011 | */ | |
1012 | if (added) { | |
1013 | locks_delete_lock(before); | |
1014 | continue; | |
1015 | } | |
1016 | /* Replace the old lock with the new one. | |
1017 | * Wake up anybody waiting for the old one, | |
1018 | * as the change in lock type might satisfy | |
1019 | * their needs. | |
1020 | */ | |
1021 | locks_wake_up_blocks(fl); | |
1022 | fl->fl_start = request->fl_start; | |
1023 | fl->fl_end = request->fl_end; | |
1024 | fl->fl_type = request->fl_type; | |
47831f35 TM |
1025 | locks_release_private(fl); |
1026 | locks_copy_private(fl, request); | |
1da177e4 | 1027 | request = fl; |
b9746ef8 | 1028 | added = true; |
1da177e4 LT |
1029 | } |
1030 | } | |
1031 | /* Go on to next lock. | |
1032 | */ | |
1033 | next_lock: | |
1034 | before = &fl->fl_next; | |
1035 | } | |
1036 | ||
0d9a490a | 1037 | /* |
1cb36012 JL |
1038 | * The above code only modifies existing locks in case of merging or |
1039 | * replacing. If new lock(s) need to be inserted all modifications are | |
1040 | * done below this, so it's safe yet to bail out. | |
0d9a490a MS |
1041 | */ |
1042 | error = -ENOLCK; /* "no luck" */ | |
1043 | if (right && left == right && !new_fl2) | |
1044 | goto out; | |
1045 | ||
1da177e4 LT |
1046 | error = 0; |
1047 | if (!added) { | |
f475ae95 TM |
1048 | if (request->fl_type == F_UNLCK) { |
1049 | if (request->fl_flags & FL_EXISTS) | |
1050 | error = -ENOENT; | |
1da177e4 | 1051 | goto out; |
f475ae95 | 1052 | } |
0d9a490a MS |
1053 | |
1054 | if (!new_fl) { | |
1055 | error = -ENOLCK; | |
1056 | goto out; | |
1057 | } | |
1da177e4 LT |
1058 | locks_copy_lock(new_fl, request); |
1059 | locks_insert_lock(before, new_fl); | |
1060 | new_fl = NULL; | |
1061 | } | |
1062 | if (right) { | |
1063 | if (left == right) { | |
1064 | /* The new lock breaks the old one in two pieces, | |
1065 | * so we have to use the second new lock. | |
1066 | */ | |
1067 | left = new_fl2; | |
1068 | new_fl2 = NULL; | |
1069 | locks_copy_lock(left, right); | |
1070 | locks_insert_lock(before, left); | |
1071 | } | |
1072 | right->fl_start = request->fl_end + 1; | |
1073 | locks_wake_up_blocks(right); | |
1074 | } | |
1075 | if (left) { | |
1076 | left->fl_end = request->fl_start - 1; | |
1077 | locks_wake_up_blocks(left); | |
1078 | } | |
1079 | out: | |
1c8c601a | 1080 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1081 | /* |
1082 | * Free any unused locks. | |
1083 | */ | |
1084 | if (new_fl) | |
1085 | locks_free_lock(new_fl); | |
1086 | if (new_fl2) | |
1087 | locks_free_lock(new_fl2); | |
1088 | return error; | |
1089 | } | |
1090 | ||
1091 | /** | |
1092 | * posix_lock_file - Apply a POSIX-style lock to a file | |
1093 | * @filp: The file to apply the lock to | |
1094 | * @fl: The lock to be applied | |
150b3934 | 1095 | * @conflock: Place to return a copy of the conflicting lock, if found. |
1da177e4 LT |
1096 | * |
1097 | * Add a POSIX style lock to a file. | |
1098 | * We merge adjacent & overlapping locks whenever possible. | |
1099 | * POSIX locks are sorted by owner task, then by starting address | |
f475ae95 TM |
1100 | * |
1101 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
1102 | * whether or not a lock was successfully freed by testing the return | |
1103 | * value for -ENOENT. | |
1da177e4 | 1104 | */ |
150b3934 | 1105 | int posix_lock_file(struct file *filp, struct file_lock *fl, |
5842add2 AA |
1106 | struct file_lock *conflock) |
1107 | { | |
496ad9aa | 1108 | return __posix_lock_file(file_inode(filp), fl, conflock); |
1da177e4 | 1109 | } |
150b3934 | 1110 | EXPORT_SYMBOL(posix_lock_file); |
1da177e4 LT |
1111 | |
1112 | /** | |
1113 | * posix_lock_file_wait - Apply a POSIX-style lock to a file | |
1114 | * @filp: The file to apply the lock to | |
1115 | * @fl: The lock to be applied | |
1116 | * | |
1117 | * Add a POSIX style lock to a file. | |
1118 | * We merge adjacent & overlapping locks whenever possible. | |
1119 | * POSIX locks are sorted by owner task, then by starting address | |
1120 | */ | |
1121 | int posix_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1122 | { | |
1123 | int error; | |
1124 | might_sleep (); | |
1125 | for (;;) { | |
150b3934 | 1126 | error = posix_lock_file(filp, fl, NULL); |
bde74e4b | 1127 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1128 | break; |
1129 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1130 | if (!error) | |
1131 | continue; | |
1132 | ||
1133 | locks_delete_block(fl); | |
1134 | break; | |
1135 | } | |
1136 | return error; | |
1137 | } | |
1138 | EXPORT_SYMBOL(posix_lock_file_wait); | |
1139 | ||
1140 | /** | |
1141 | * locks_mandatory_locked - Check for an active lock | |
1142 | * @inode: the file to check | |
1143 | * | |
1144 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1145 | * This function is called from locks_verify_locked() only. | |
1146 | */ | |
1147 | int locks_mandatory_locked(struct inode *inode) | |
1148 | { | |
1149 | fl_owner_t owner = current->files; | |
1150 | struct file_lock *fl; | |
1151 | ||
1152 | /* | |
1153 | * Search the lock list for this inode for any POSIX locks. | |
1154 | */ | |
1c8c601a | 1155 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1156 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
1157 | if (!IS_POSIX(fl)) | |
1158 | continue; | |
1159 | if (fl->fl_owner != owner) | |
1160 | break; | |
1161 | } | |
1c8c601a | 1162 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1163 | return fl ? -EAGAIN : 0; |
1164 | } | |
1165 | ||
1166 | /** | |
1167 | * locks_mandatory_area - Check for a conflicting lock | |
1168 | * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ | |
1169 | * for shared | |
1170 | * @inode: the file to check | |
1171 | * @filp: how the file was opened (if it was) | |
1172 | * @offset: start of area to check | |
1173 | * @count: length of area to check | |
1174 | * | |
1175 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1176 | * This function is called from rw_verify_area() and | |
1177 | * locks_verify_truncate(). | |
1178 | */ | |
1179 | int locks_mandatory_area(int read_write, struct inode *inode, | |
1180 | struct file *filp, loff_t offset, | |
1181 | size_t count) | |
1182 | { | |
1183 | struct file_lock fl; | |
1184 | int error; | |
1185 | ||
1186 | locks_init_lock(&fl); | |
1187 | fl.fl_owner = current->files; | |
1188 | fl.fl_pid = current->tgid; | |
1189 | fl.fl_file = filp; | |
1190 | fl.fl_flags = FL_POSIX | FL_ACCESS; | |
1191 | if (filp && !(filp->f_flags & O_NONBLOCK)) | |
1192 | fl.fl_flags |= FL_SLEEP; | |
1193 | fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK; | |
1194 | fl.fl_start = offset; | |
1195 | fl.fl_end = offset + count - 1; | |
1196 | ||
1197 | for (;;) { | |
150b3934 | 1198 | error = __posix_lock_file(inode, &fl, NULL); |
bde74e4b | 1199 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1200 | break; |
1201 | error = wait_event_interruptible(fl.fl_wait, !fl.fl_next); | |
1202 | if (!error) { | |
1203 | /* | |
1204 | * If we've been sleeping someone might have | |
1205 | * changed the permissions behind our back. | |
1206 | */ | |
a16877ca | 1207 | if (__mandatory_lock(inode)) |
1da177e4 LT |
1208 | continue; |
1209 | } | |
1210 | ||
1211 | locks_delete_block(&fl); | |
1212 | break; | |
1213 | } | |
1214 | ||
1215 | return error; | |
1216 | } | |
1217 | ||
1218 | EXPORT_SYMBOL(locks_mandatory_area); | |
1219 | ||
778fc546 BF |
1220 | static void lease_clear_pending(struct file_lock *fl, int arg) |
1221 | { | |
1222 | switch (arg) { | |
1223 | case F_UNLCK: | |
1224 | fl->fl_flags &= ~FL_UNLOCK_PENDING; | |
1225 | /* fall through: */ | |
1226 | case F_RDLCK: | |
1227 | fl->fl_flags &= ~FL_DOWNGRADE_PENDING; | |
1228 | } | |
1229 | } | |
1230 | ||
1da177e4 LT |
1231 | /* We already had a lease on this file; just change its type */ |
1232 | int lease_modify(struct file_lock **before, int arg) | |
1233 | { | |
1234 | struct file_lock *fl = *before; | |
1235 | int error = assign_type(fl, arg); | |
1236 | ||
1237 | if (error) | |
1238 | return error; | |
778fc546 | 1239 | lease_clear_pending(fl, arg); |
1da177e4 | 1240 | locks_wake_up_blocks(fl); |
3b6e2723 FB |
1241 | if (arg == F_UNLCK) { |
1242 | struct file *filp = fl->fl_file; | |
1243 | ||
1244 | f_delown(filp); | |
1245 | filp->f_owner.signum = 0; | |
96d6d59c BF |
1246 | fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync); |
1247 | if (fl->fl_fasync != NULL) { | |
1248 | printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync); | |
1249 | fl->fl_fasync = NULL; | |
1250 | } | |
1da177e4 | 1251 | locks_delete_lock(before); |
3b6e2723 | 1252 | } |
1da177e4 LT |
1253 | return 0; |
1254 | } | |
1255 | ||
1256 | EXPORT_SYMBOL(lease_modify); | |
1257 | ||
778fc546 BF |
1258 | static bool past_time(unsigned long then) |
1259 | { | |
1260 | if (!then) | |
1261 | /* 0 is a special value meaning "this never expires": */ | |
1262 | return false; | |
1263 | return time_after(jiffies, then); | |
1264 | } | |
1265 | ||
1da177e4 LT |
1266 | static void time_out_leases(struct inode *inode) |
1267 | { | |
1268 | struct file_lock **before; | |
1269 | struct file_lock *fl; | |
1270 | ||
1271 | before = &inode->i_flock; | |
ab83fa4b | 1272 | while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) { |
778fc546 BF |
1273 | if (past_time(fl->fl_downgrade_time)) |
1274 | lease_modify(before, F_RDLCK); | |
1275 | if (past_time(fl->fl_break_time)) | |
1276 | lease_modify(before, F_UNLCK); | |
1da177e4 LT |
1277 | if (fl == *before) /* lease_modify may have freed fl */ |
1278 | before = &fl->fl_next; | |
1279 | } | |
1280 | } | |
1281 | ||
df4e8d2c BF |
1282 | static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker) |
1283 | { | |
1284 | if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) | |
1285 | return false; | |
1286 | return locks_conflict(breaker, lease); | |
1287 | } | |
1288 | ||
1da177e4 LT |
1289 | /** |
1290 | * __break_lease - revoke all outstanding leases on file | |
1291 | * @inode: the inode of the file to return | |
df4e8d2c BF |
1292 | * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR: |
1293 | * break all leases | |
1294 | * @type: FL_LEASE: break leases and delegations; FL_DELEG: break | |
1295 | * only delegations | |
1da177e4 | 1296 | * |
87250dd2 | 1297 | * break_lease (inlined for speed) has checked there already is at least |
1298 | * some kind of lock (maybe a lease) on this file. Leases are broken on | |
1299 | * a call to open() or truncate(). This function can sleep unless you | |
1da177e4 LT |
1300 | * specified %O_NONBLOCK to your open(). |
1301 | */ | |
df4e8d2c | 1302 | int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) |
1da177e4 | 1303 | { |
778fc546 | 1304 | int error = 0; |
1da177e4 LT |
1305 | struct file_lock *new_fl, *flock; |
1306 | struct file_lock *fl; | |
1da177e4 LT |
1307 | unsigned long break_time; |
1308 | int i_have_this_lease = 0; | |
df4e8d2c | 1309 | bool lease_conflict = false; |
8737c930 | 1310 | int want_write = (mode & O_ACCMODE) != O_RDONLY; |
1da177e4 | 1311 | |
8737c930 | 1312 | new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK); |
6d4b9e38 LT |
1313 | if (IS_ERR(new_fl)) |
1314 | return PTR_ERR(new_fl); | |
df4e8d2c | 1315 | new_fl->fl_flags = type; |
1da177e4 | 1316 | |
1c8c601a | 1317 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1318 | |
1319 | time_out_leases(inode); | |
1320 | ||
1321 | flock = inode->i_flock; | |
1322 | if ((flock == NULL) || !IS_LEASE(flock)) | |
1323 | goto out; | |
1324 | ||
df4e8d2c BF |
1325 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { |
1326 | if (leases_conflict(fl, new_fl)) { | |
1327 | lease_conflict = true; | |
1328 | if (fl->fl_owner == current->files) | |
1329 | i_have_this_lease = 1; | |
1330 | } | |
1331 | } | |
1332 | if (!lease_conflict) | |
778fc546 BF |
1333 | goto out; |
1334 | ||
1da177e4 LT |
1335 | break_time = 0; |
1336 | if (lease_break_time > 0) { | |
1337 | break_time = jiffies + lease_break_time * HZ; | |
1338 | if (break_time == 0) | |
1339 | break_time++; /* so that 0 means no break time */ | |
1340 | } | |
1341 | ||
1342 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { | |
df4e8d2c BF |
1343 | if (!leases_conflict(fl, new_fl)) |
1344 | continue; | |
778fc546 BF |
1345 | if (want_write) { |
1346 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1347 | continue; | |
1348 | fl->fl_flags |= FL_UNLOCK_PENDING; | |
1da177e4 | 1349 | fl->fl_break_time = break_time; |
778fc546 BF |
1350 | } else { |
1351 | if (lease_breaking(flock)) | |
1352 | continue; | |
1353 | fl->fl_flags |= FL_DOWNGRADE_PENDING; | |
1354 | fl->fl_downgrade_time = break_time; | |
1da177e4 | 1355 | } |
778fc546 | 1356 | fl->fl_lmops->lm_break(fl); |
1da177e4 LT |
1357 | } |
1358 | ||
1359 | if (i_have_this_lease || (mode & O_NONBLOCK)) { | |
1360 | error = -EWOULDBLOCK; | |
1361 | goto out; | |
1362 | } | |
1363 | ||
1364 | restart: | |
1365 | break_time = flock->fl_break_time; | |
1366 | if (break_time != 0) { | |
1367 | break_time -= jiffies; | |
1368 | if (break_time == 0) | |
1369 | break_time++; | |
1370 | } | |
4321e01e | 1371 | locks_insert_block(flock, new_fl); |
1c8c601a | 1372 | spin_unlock(&inode->i_lock); |
4321e01e MW |
1373 | error = wait_event_interruptible_timeout(new_fl->fl_wait, |
1374 | !new_fl->fl_next, break_time); | |
1c8c601a JL |
1375 | spin_lock(&inode->i_lock); |
1376 | locks_delete_block(new_fl); | |
1da177e4 LT |
1377 | if (error >= 0) { |
1378 | if (error == 0) | |
1379 | time_out_leases(inode); | |
778fc546 BF |
1380 | /* |
1381 | * Wait for the next conflicting lease that has not been | |
1382 | * broken yet | |
1383 | */ | |
1da177e4 LT |
1384 | for (flock = inode->i_flock; flock && IS_LEASE(flock); |
1385 | flock = flock->fl_next) { | |
df4e8d2c | 1386 | if (leases_conflict(new_fl, flock)) |
1da177e4 LT |
1387 | goto restart; |
1388 | } | |
1389 | error = 0; | |
1390 | } | |
1391 | ||
1392 | out: | |
1c8c601a | 1393 | spin_unlock(&inode->i_lock); |
6d4b9e38 | 1394 | locks_free_lock(new_fl); |
1da177e4 LT |
1395 | return error; |
1396 | } | |
1397 | ||
1398 | EXPORT_SYMBOL(__break_lease); | |
1399 | ||
1400 | /** | |
a6b91919 | 1401 | * lease_get_mtime - get the last modified time of an inode |
1da177e4 LT |
1402 | * @inode: the inode |
1403 | * @time: pointer to a timespec which will contain the last modified time | |
1404 | * | |
1405 | * This is to force NFS clients to flush their caches for files with | |
1406 | * exclusive leases. The justification is that if someone has an | |
a6b91919 | 1407 | * exclusive lease, then they could be modifying it. |
1da177e4 LT |
1408 | */ |
1409 | void lease_get_mtime(struct inode *inode, struct timespec *time) | |
1410 | { | |
1411 | struct file_lock *flock = inode->i_flock; | |
0ee5c6d6 | 1412 | if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK)) |
1da177e4 LT |
1413 | *time = current_fs_time(inode->i_sb); |
1414 | else | |
1415 | *time = inode->i_mtime; | |
1416 | } | |
1417 | ||
1418 | EXPORT_SYMBOL(lease_get_mtime); | |
1419 | ||
1420 | /** | |
1421 | * fcntl_getlease - Enquire what lease is currently active | |
1422 | * @filp: the file | |
1423 | * | |
1424 | * The value returned by this function will be one of | |
1425 | * (if no lease break is pending): | |
1426 | * | |
1427 | * %F_RDLCK to indicate a shared lease is held. | |
1428 | * | |
1429 | * %F_WRLCK to indicate an exclusive lease is held. | |
1430 | * | |
1431 | * %F_UNLCK to indicate no lease is held. | |
1432 | * | |
1433 | * (if a lease break is pending): | |
1434 | * | |
1435 | * %F_RDLCK to indicate an exclusive lease needs to be | |
1436 | * changed to a shared lease (or removed). | |
1437 | * | |
1438 | * %F_UNLCK to indicate the lease needs to be removed. | |
1439 | * | |
1440 | * XXX: sfr & willy disagree over whether F_INPROGRESS | |
1441 | * should be returned to userspace. | |
1442 | */ | |
1443 | int fcntl_getlease(struct file *filp) | |
1444 | { | |
1445 | struct file_lock *fl; | |
1c8c601a | 1446 | struct inode *inode = file_inode(filp); |
1da177e4 LT |
1447 | int type = F_UNLCK; |
1448 | ||
1c8c601a | 1449 | spin_lock(&inode->i_lock); |
496ad9aa AV |
1450 | time_out_leases(file_inode(filp)); |
1451 | for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl); | |
1da177e4 LT |
1452 | fl = fl->fl_next) { |
1453 | if (fl->fl_file == filp) { | |
778fc546 | 1454 | type = target_leasetype(fl); |
1da177e4 LT |
1455 | break; |
1456 | } | |
1457 | } | |
1c8c601a | 1458 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1459 | return type; |
1460 | } | |
1461 | ||
24cbe784 JL |
1462 | /** |
1463 | * check_conflicting_open - see if the given dentry points to a file that has | |
1464 | * an existing open that would conflict with the | |
1465 | * desired lease. | |
1466 | * @dentry: dentry to check | |
1467 | * @arg: type of lease that we're trying to acquire | |
1468 | * | |
1469 | * Check to see if there's an existing open fd on this file that would | |
1470 | * conflict with the lease we're trying to set. | |
1471 | */ | |
1472 | static int | |
1473 | check_conflicting_open(const struct dentry *dentry, const long arg) | |
1474 | { | |
1475 | int ret = 0; | |
1476 | struct inode *inode = dentry->d_inode; | |
1477 | ||
1478 | if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) | |
1479 | return -EAGAIN; | |
1480 | ||
1481 | if ((arg == F_WRLCK) && ((d_count(dentry) > 1) || | |
1482 | (atomic_read(&inode->i_count) > 1))) | |
1483 | ret = -EAGAIN; | |
1484 | ||
1485 | return ret; | |
1486 | } | |
1487 | ||
d4f22d19 | 1488 | static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp) |
1da177e4 | 1489 | { |
7eaae282 | 1490 | struct file_lock *fl, **before, **my_before = NULL, *lease; |
0f7fc9e4 | 1491 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 1492 | struct inode *inode = dentry->d_inode; |
df4e8d2c | 1493 | bool is_deleg = (*flp)->fl_flags & FL_DELEG; |
c1f24ef4 | 1494 | int error; |
1da177e4 | 1495 | |
096657b6 | 1496 | lease = *flp; |
df4e8d2c BF |
1497 | /* |
1498 | * In the delegation case we need mutual exclusion with | |
1499 | * a number of operations that take the i_mutex. We trylock | |
1500 | * because delegations are an optional optimization, and if | |
1501 | * there's some chance of a conflict--we'd rather not | |
1502 | * bother, maybe that's a sign this just isn't a good file to | |
1503 | * hand out a delegation on. | |
1504 | */ | |
1505 | if (is_deleg && !mutex_trylock(&inode->i_mutex)) | |
1506 | return -EAGAIN; | |
1507 | ||
1508 | if (is_deleg && arg == F_WRLCK) { | |
1509 | /* Write delegations are not currently supported: */ | |
4fdb793f | 1510 | mutex_unlock(&inode->i_mutex); |
df4e8d2c BF |
1511 | WARN_ON_ONCE(1); |
1512 | return -EINVAL; | |
1513 | } | |
096657b6 | 1514 | |
24cbe784 JL |
1515 | error = check_conflicting_open(dentry, arg); |
1516 | if (error) | |
096657b6 | 1517 | goto out; |
6d5e8b05 | 1518 | |
1da177e4 LT |
1519 | /* |
1520 | * At this point, we know that if there is an exclusive | |
1521 | * lease on this file, then we hold it on this filp | |
1522 | * (otherwise our open of this file would have blocked). | |
1523 | * And if we are trying to acquire an exclusive lease, | |
1524 | * then the file is not open by anyone (including us) | |
1525 | * except for this filp. | |
1526 | */ | |
c1f24ef4 | 1527 | error = -EAGAIN; |
1da177e4 LT |
1528 | for (before = &inode->i_flock; |
1529 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1530 | before = &fl->fl_next) { | |
c1f24ef4 | 1531 | if (fl->fl_file == filp) { |
1da177e4 | 1532 | my_before = before; |
c1f24ef4 BF |
1533 | continue; |
1534 | } | |
1535 | /* | |
1536 | * No exclusive leases if someone else has a lease on | |
1537 | * this file: | |
1538 | */ | |
1539 | if (arg == F_WRLCK) | |
1540 | goto out; | |
1541 | /* | |
1542 | * Modifying our existing lease is OK, but no getting a | |
1543 | * new lease if someone else is opening for write: | |
1544 | */ | |
1545 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1546 | goto out; | |
1da177e4 LT |
1547 | } |
1548 | ||
1da177e4 | 1549 | if (my_before != NULL) { |
8fb47a4f | 1550 | error = lease->fl_lmops->lm_change(my_before, arg); |
51ee4b84 CH |
1551 | if (!error) |
1552 | *flp = *my_before; | |
1da177e4 LT |
1553 | goto out; |
1554 | } | |
1555 | ||
1da177e4 LT |
1556 | error = -EINVAL; |
1557 | if (!leases_enable) | |
1558 | goto out; | |
1559 | ||
c5b1f0d9 | 1560 | locks_insert_lock(before, lease); |
24cbe784 JL |
1561 | /* |
1562 | * The check in break_lease() is lockless. It's possible for another | |
1563 | * open to race in after we did the earlier check for a conflicting | |
1564 | * open but before the lease was inserted. Check again for a | |
1565 | * conflicting open and cancel the lease if there is one. | |
1566 | * | |
1567 | * We also add a barrier here to ensure that the insertion of the lock | |
1568 | * precedes these checks. | |
1569 | */ | |
1570 | smp_mb(); | |
1571 | error = check_conflicting_open(dentry, arg); | |
1572 | if (error) | |
1573 | locks_unlink_lock(flp); | |
1da177e4 | 1574 | out: |
df4e8d2c BF |
1575 | if (is_deleg) |
1576 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
1577 | return error; |
1578 | } | |
8335ebd9 | 1579 | |
d4f22d19 | 1580 | static int generic_delete_lease(struct file *filp, struct file_lock **flp) |
8335ebd9 BF |
1581 | { |
1582 | struct file_lock *fl, **before; | |
1583 | struct dentry *dentry = filp->f_path.dentry; | |
1584 | struct inode *inode = dentry->d_inode; | |
1585 | ||
1586 | for (before = &inode->i_flock; | |
1587 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1588 | before = &fl->fl_next) { | |
1589 | if (fl->fl_file != filp) | |
1590 | continue; | |
1591 | return (*flp)->fl_lmops->lm_change(before, F_UNLCK); | |
1592 | } | |
1593 | return -EAGAIN; | |
1594 | } | |
1595 | ||
1596 | /** | |
1597 | * generic_setlease - sets a lease on an open file | |
1598 | * @filp: file pointer | |
1599 | * @arg: type of lease to obtain | |
1600 | * @flp: input - file_lock to use, output - file_lock inserted | |
1601 | * | |
1602 | * The (input) flp->fl_lmops->lm_break function is required | |
1603 | * by break_lease(). | |
1604 | * | |
1c8c601a | 1605 | * Called with inode->i_lock held. |
8335ebd9 BF |
1606 | */ |
1607 | int generic_setlease(struct file *filp, long arg, struct file_lock **flp) | |
1608 | { | |
1609 | struct dentry *dentry = filp->f_path.dentry; | |
1610 | struct inode *inode = dentry->d_inode; | |
1611 | int error; | |
1612 | ||
8e96e3b7 | 1613 | if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE)) |
8335ebd9 BF |
1614 | return -EACCES; |
1615 | if (!S_ISREG(inode->i_mode)) | |
1616 | return -EINVAL; | |
1617 | error = security_file_lock(filp, arg); | |
1618 | if (error) | |
1619 | return error; | |
1620 | ||
1621 | time_out_leases(inode); | |
1622 | ||
1623 | BUG_ON(!(*flp)->fl_lmops->lm_break); | |
1624 | ||
1625 | switch (arg) { | |
1626 | case F_UNLCK: | |
1627 | return generic_delete_lease(filp, flp); | |
1628 | case F_RDLCK: | |
1629 | case F_WRLCK: | |
1630 | return generic_add_lease(filp, arg, flp); | |
1631 | default: | |
8d657eb3 | 1632 | return -EINVAL; |
8335ebd9 BF |
1633 | } |
1634 | } | |
0af1a450 | 1635 | EXPORT_SYMBOL(generic_setlease); |
1da177e4 | 1636 | |
b89f4321 AB |
1637 | static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1638 | { | |
72c2d531 | 1639 | if (filp->f_op->setlease) |
b89f4321 AB |
1640 | return filp->f_op->setlease(filp, arg, lease); |
1641 | else | |
1642 | return generic_setlease(filp, arg, lease); | |
1643 | } | |
1644 | ||
1645 | /** | |
a9933cea | 1646 | * vfs_setlease - sets a lease on an open file |
1da177e4 LT |
1647 | * @filp: file pointer |
1648 | * @arg: type of lease to obtain | |
1649 | * @lease: file_lock to use | |
1650 | * | |
1651 | * Call this to establish a lease on the file. | |
8fb47a4f | 1652 | * The (*lease)->fl_lmops->lm_break operation must be set; if not, |
f9ffed26 BF |
1653 | * break_lease will oops! |
1654 | * | |
1655 | * This will call the filesystem's setlease file method, if | |
1656 | * defined. Note that there is no getlease method; instead, the | |
1657 | * filesystem setlease method should call back to setlease() to | |
1658 | * add a lease to the inode's lease list, where fcntl_getlease() can | |
1659 | * find it. Since fcntl_getlease() only reports whether the current | |
1660 | * task holds a lease, a cluster filesystem need only do this for | |
1661 | * leases held by processes on this node. | |
1662 | * | |
1663 | * There is also no break_lease method; filesystems that | |
c9404c9c | 1664 | * handle their own leases should break leases themselves from the |
f9ffed26 BF |
1665 | * filesystem's open, create, and (on truncate) setattr methods. |
1666 | * | |
1667 | * Warning: the only current setlease methods exist only to disable | |
1668 | * leases in certain cases. More vfs changes may be required to | |
1669 | * allow a full filesystem lease implementation. | |
1da177e4 LT |
1670 | */ |
1671 | ||
a9933cea | 1672 | int vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1da177e4 | 1673 | { |
1c8c601a | 1674 | struct inode *inode = file_inode(filp); |
1da177e4 LT |
1675 | int error; |
1676 | ||
1c8c601a | 1677 | spin_lock(&inode->i_lock); |
b89f4321 | 1678 | error = __vfs_setlease(filp, arg, lease); |
1c8c601a | 1679 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1680 | |
1681 | return error; | |
1682 | } | |
a9933cea | 1683 | EXPORT_SYMBOL_GPL(vfs_setlease); |
1da177e4 | 1684 | |
0ceaf6c7 BF |
1685 | static int do_fcntl_delete_lease(struct file *filp) |
1686 | { | |
1687 | struct file_lock fl, *flp = &fl; | |
1688 | ||
1689 | lease_init(filp, F_UNLCK, flp); | |
1690 | ||
1691 | return vfs_setlease(filp, F_UNLCK, &flp); | |
1692 | } | |
1693 | ||
1694 | static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg) | |
1da177e4 | 1695 | { |
3df057ac | 1696 | struct file_lock *fl, *ret; |
1c8c601a | 1697 | struct inode *inode = file_inode(filp); |
f7347ce4 | 1698 | struct fasync_struct *new; |
1da177e4 LT |
1699 | int error; |
1700 | ||
c5b1f0d9 AB |
1701 | fl = lease_alloc(filp, arg); |
1702 | if (IS_ERR(fl)) | |
1703 | return PTR_ERR(fl); | |
1da177e4 | 1704 | |
f7347ce4 LT |
1705 | new = fasync_alloc(); |
1706 | if (!new) { | |
1707 | locks_free_lock(fl); | |
1708 | return -ENOMEM; | |
1709 | } | |
3df057ac | 1710 | ret = fl; |
1c8c601a | 1711 | spin_lock(&inode->i_lock); |
8896b93f | 1712 | error = __vfs_setlease(filp, arg, &ret); |
51ee4b84 | 1713 | if (error) { |
1c8c601a | 1714 | spin_unlock(&inode->i_lock); |
51ee4b84 CH |
1715 | locks_free_lock(fl); |
1716 | goto out_free_fasync; | |
1717 | } | |
3df057ac BF |
1718 | if (ret != fl) |
1719 | locks_free_lock(fl); | |
1da177e4 | 1720 | |
f7347ce4 LT |
1721 | /* |
1722 | * fasync_insert_entry() returns the old entry if any. | |
1723 | * If there was no old entry, then it used 'new' and | |
1724 | * inserted it into the fasync list. Clear new so that | |
1725 | * we don't release it here. | |
1726 | */ | |
3df057ac | 1727 | if (!fasync_insert_entry(fd, filp, &ret->fl_fasync, new)) |
f7347ce4 LT |
1728 | new = NULL; |
1729 | ||
8896b93f | 1730 | error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); |
1c8c601a | 1731 | spin_unlock(&inode->i_lock); |
51ee4b84 CH |
1732 | |
1733 | out_free_fasync: | |
f7347ce4 LT |
1734 | if (new) |
1735 | fasync_free(new); | |
1da177e4 LT |
1736 | return error; |
1737 | } | |
1738 | ||
0ceaf6c7 BF |
1739 | /** |
1740 | * fcntl_setlease - sets a lease on an open file | |
1741 | * @fd: open file descriptor | |
1742 | * @filp: file pointer | |
1743 | * @arg: type of lease to obtain | |
1744 | * | |
1745 | * Call this fcntl to establish a lease on the file. | |
1746 | * Note that you also need to call %F_SETSIG to | |
1747 | * receive a signal when the lease is broken. | |
1748 | */ | |
1749 | int fcntl_setlease(unsigned int fd, struct file *filp, long arg) | |
1750 | { | |
1751 | if (arg == F_UNLCK) | |
1752 | return do_fcntl_delete_lease(filp); | |
1753 | return do_fcntl_add_lease(fd, filp, arg); | |
1754 | } | |
1755 | ||
1da177e4 LT |
1756 | /** |
1757 | * flock_lock_file_wait - Apply a FLOCK-style lock to a file | |
1758 | * @filp: The file to apply the lock to | |
1759 | * @fl: The lock to be applied | |
1760 | * | |
1761 | * Add a FLOCK style lock to a file. | |
1762 | */ | |
1763 | int flock_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1764 | { | |
1765 | int error; | |
1766 | might_sleep(); | |
1767 | for (;;) { | |
1768 | error = flock_lock_file(filp, fl); | |
bde74e4b | 1769 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1770 | break; |
1771 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1772 | if (!error) | |
1773 | continue; | |
1774 | ||
1775 | locks_delete_block(fl); | |
1776 | break; | |
1777 | } | |
1778 | return error; | |
1779 | } | |
1780 | ||
1781 | EXPORT_SYMBOL(flock_lock_file_wait); | |
1782 | ||
1783 | /** | |
1784 | * sys_flock: - flock() system call. | |
1785 | * @fd: the file descriptor to lock. | |
1786 | * @cmd: the type of lock to apply. | |
1787 | * | |
1788 | * Apply a %FL_FLOCK style lock to an open file descriptor. | |
1789 | * The @cmd can be one of | |
1790 | * | |
1791 | * %LOCK_SH -- a shared lock. | |
1792 | * | |
1793 | * %LOCK_EX -- an exclusive lock. | |
1794 | * | |
1795 | * %LOCK_UN -- remove an existing lock. | |
1796 | * | |
1797 | * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes. | |
1798 | * | |
1799 | * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other | |
1800 | * processes read and write access respectively. | |
1801 | */ | |
002c8976 | 1802 | SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) |
1da177e4 | 1803 | { |
2903ff01 | 1804 | struct fd f = fdget(fd); |
1da177e4 LT |
1805 | struct file_lock *lock; |
1806 | int can_sleep, unlock; | |
1807 | int error; | |
1808 | ||
1809 | error = -EBADF; | |
2903ff01 | 1810 | if (!f.file) |
1da177e4 LT |
1811 | goto out; |
1812 | ||
1813 | can_sleep = !(cmd & LOCK_NB); | |
1814 | cmd &= ~LOCK_NB; | |
1815 | unlock = (cmd == LOCK_UN); | |
1816 | ||
aeb5d727 | 1817 | if (!unlock && !(cmd & LOCK_MAND) && |
2903ff01 | 1818 | !(f.file->f_mode & (FMODE_READ|FMODE_WRITE))) |
1da177e4 LT |
1819 | goto out_putf; |
1820 | ||
2903ff01 | 1821 | error = flock_make_lock(f.file, &lock, cmd); |
1da177e4 LT |
1822 | if (error) |
1823 | goto out_putf; | |
1824 | if (can_sleep) | |
1825 | lock->fl_flags |= FL_SLEEP; | |
1826 | ||
2903ff01 | 1827 | error = security_file_lock(f.file, lock->fl_type); |
1da177e4 LT |
1828 | if (error) |
1829 | goto out_free; | |
1830 | ||
72c2d531 | 1831 | if (f.file->f_op->flock) |
2903ff01 | 1832 | error = f.file->f_op->flock(f.file, |
1da177e4 LT |
1833 | (can_sleep) ? F_SETLKW : F_SETLK, |
1834 | lock); | |
1835 | else | |
2903ff01 | 1836 | error = flock_lock_file_wait(f.file, lock); |
1da177e4 LT |
1837 | |
1838 | out_free: | |
993dfa87 | 1839 | locks_free_lock(lock); |
1da177e4 LT |
1840 | |
1841 | out_putf: | |
2903ff01 | 1842 | fdput(f); |
1da177e4 LT |
1843 | out: |
1844 | return error; | |
1845 | } | |
1846 | ||
3ee17abd BF |
1847 | /** |
1848 | * vfs_test_lock - test file byte range lock | |
1849 | * @filp: The file to test lock for | |
6924c554 | 1850 | * @fl: The lock to test; also used to hold result |
3ee17abd BF |
1851 | * |
1852 | * Returns -ERRNO on failure. Indicates presence of conflicting lock by | |
1853 | * setting conf->fl_type to something other than F_UNLCK. | |
1854 | */ | |
1855 | int vfs_test_lock(struct file *filp, struct file_lock *fl) | |
1856 | { | |
72c2d531 | 1857 | if (filp->f_op->lock) |
3ee17abd BF |
1858 | return filp->f_op->lock(filp, F_GETLK, fl); |
1859 | posix_test_lock(filp, fl); | |
1860 | return 0; | |
1861 | } | |
1862 | EXPORT_SYMBOL_GPL(vfs_test_lock); | |
1863 | ||
c2fa1b8a BF |
1864 | static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) |
1865 | { | |
1866 | flock->l_pid = fl->fl_pid; | |
1867 | #if BITS_PER_LONG == 32 | |
1868 | /* | |
1869 | * Make sure we can represent the posix lock via | |
1870 | * legacy 32bit flock. | |
1871 | */ | |
1872 | if (fl->fl_start > OFFT_OFFSET_MAX) | |
1873 | return -EOVERFLOW; | |
1874 | if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX) | |
1875 | return -EOVERFLOW; | |
1876 | #endif | |
1877 | flock->l_start = fl->fl_start; | |
1878 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1879 | fl->fl_end - fl->fl_start + 1; | |
1880 | flock->l_whence = 0; | |
129a84de | 1881 | flock->l_type = fl->fl_type; |
c2fa1b8a BF |
1882 | return 0; |
1883 | } | |
1884 | ||
1885 | #if BITS_PER_LONG == 32 | |
1886 | static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) | |
1887 | { | |
1888 | flock->l_pid = fl->fl_pid; | |
1889 | flock->l_start = fl->fl_start; | |
1890 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1891 | fl->fl_end - fl->fl_start + 1; | |
1892 | flock->l_whence = 0; | |
1893 | flock->l_type = fl->fl_type; | |
1894 | } | |
1895 | #endif | |
1896 | ||
1da177e4 LT |
1897 | /* Report the first existing lock that would conflict with l. |
1898 | * This implements the F_GETLK command of fcntl(). | |
1899 | */ | |
1900 | int fcntl_getlk(struct file *filp, struct flock __user *l) | |
1901 | { | |
9d6a8c5c | 1902 | struct file_lock file_lock; |
1da177e4 LT |
1903 | struct flock flock; |
1904 | int error; | |
1905 | ||
1906 | error = -EFAULT; | |
1907 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1908 | goto out; | |
1909 | error = -EINVAL; | |
1910 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
1911 | goto out; | |
1912 | ||
1913 | error = flock_to_posix_lock(filp, &file_lock, &flock); | |
1914 | if (error) | |
1915 | goto out; | |
1916 | ||
3ee17abd BF |
1917 | error = vfs_test_lock(filp, &file_lock); |
1918 | if (error) | |
1919 | goto out; | |
1da177e4 | 1920 | |
9d6a8c5c ME |
1921 | flock.l_type = file_lock.fl_type; |
1922 | if (file_lock.fl_type != F_UNLCK) { | |
1923 | error = posix_lock_to_flock(&flock, &file_lock); | |
c2fa1b8a | 1924 | if (error) |
1da177e4 | 1925 | goto out; |
1da177e4 LT |
1926 | } |
1927 | error = -EFAULT; | |
1928 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
1929 | error = 0; | |
1930 | out: | |
1931 | return error; | |
1932 | } | |
1933 | ||
7723ec97 ME |
1934 | /** |
1935 | * vfs_lock_file - file byte range lock | |
1936 | * @filp: The file to apply the lock to | |
1937 | * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.) | |
1938 | * @fl: The lock to be applied | |
150b3934 ME |
1939 | * @conf: Place to return a copy of the conflicting lock, if found. |
1940 | * | |
1941 | * A caller that doesn't care about the conflicting lock may pass NULL | |
1942 | * as the final argument. | |
1943 | * | |
1944 | * If the filesystem defines a private ->lock() method, then @conf will | |
1945 | * be left unchanged; so a caller that cares should initialize it to | |
1946 | * some acceptable default. | |
2beb6614 ME |
1947 | * |
1948 | * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX | |
1949 | * locks, the ->lock() interface may return asynchronously, before the lock has | |
1950 | * been granted or denied by the underlying filesystem, if (and only if) | |
8fb47a4f | 1951 | * lm_grant is set. Callers expecting ->lock() to return asynchronously |
2beb6614 ME |
1952 | * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if) |
1953 | * the request is for a blocking lock. When ->lock() does return asynchronously, | |
8fb47a4f | 1954 | * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock |
2beb6614 ME |
1955 | * request completes. |
1956 | * If the request is for non-blocking lock the file system should return | |
bde74e4b MS |
1957 | * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine |
1958 | * with the result. If the request timed out the callback routine will return a | |
2beb6614 ME |
1959 | * nonzero return code and the file system should release the lock. The file |
1960 | * system is also responsible to keep a corresponding posix lock when it | |
1961 | * grants a lock so the VFS can find out which locks are locally held and do | |
1962 | * the correct lock cleanup when required. | |
1963 | * The underlying filesystem must not drop the kernel lock or call | |
8fb47a4f | 1964 | * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED |
2beb6614 | 1965 | * return code. |
7723ec97 | 1966 | */ |
150b3934 | 1967 | int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf) |
7723ec97 | 1968 | { |
72c2d531 | 1969 | if (filp->f_op->lock) |
7723ec97 ME |
1970 | return filp->f_op->lock(filp, cmd, fl); |
1971 | else | |
150b3934 | 1972 | return posix_lock_file(filp, fl, conf); |
7723ec97 ME |
1973 | } |
1974 | EXPORT_SYMBOL_GPL(vfs_lock_file); | |
1975 | ||
b648a6de MS |
1976 | static int do_lock_file_wait(struct file *filp, unsigned int cmd, |
1977 | struct file_lock *fl) | |
1978 | { | |
1979 | int error; | |
1980 | ||
1981 | error = security_file_lock(filp, fl->fl_type); | |
1982 | if (error) | |
1983 | return error; | |
1984 | ||
764c76b3 MS |
1985 | for (;;) { |
1986 | error = vfs_lock_file(filp, cmd, fl, NULL); | |
1987 | if (error != FILE_LOCK_DEFERRED) | |
b648a6de | 1988 | break; |
764c76b3 MS |
1989 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); |
1990 | if (!error) | |
1991 | continue; | |
1992 | ||
1993 | locks_delete_block(fl); | |
1994 | break; | |
b648a6de MS |
1995 | } |
1996 | ||
1997 | return error; | |
1998 | } | |
1999 | ||
1da177e4 LT |
2000 | /* Apply the lock described by l to an open file descriptor. |
2001 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2002 | */ | |
c293621b PS |
2003 | int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, |
2004 | struct flock __user *l) | |
1da177e4 LT |
2005 | { |
2006 | struct file_lock *file_lock = locks_alloc_lock(); | |
2007 | struct flock flock; | |
2008 | struct inode *inode; | |
0b2bac2f | 2009 | struct file *f; |
1da177e4 LT |
2010 | int error; |
2011 | ||
2012 | if (file_lock == NULL) | |
2013 | return -ENOLCK; | |
2014 | ||
2015 | /* | |
2016 | * This might block, so we do it before checking the inode. | |
2017 | */ | |
2018 | error = -EFAULT; | |
2019 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2020 | goto out; | |
2021 | ||
496ad9aa | 2022 | inode = file_inode(filp); |
1da177e4 LT |
2023 | |
2024 | /* Don't allow mandatory locks on files that may be memory mapped | |
2025 | * and shared. | |
2026 | */ | |
a16877ca | 2027 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
2028 | error = -EAGAIN; |
2029 | goto out; | |
2030 | } | |
2031 | ||
c293621b | 2032 | again: |
1da177e4 LT |
2033 | error = flock_to_posix_lock(filp, file_lock, &flock); |
2034 | if (error) | |
2035 | goto out; | |
2036 | if (cmd == F_SETLKW) { | |
2037 | file_lock->fl_flags |= FL_SLEEP; | |
2038 | } | |
2039 | ||
b648a6de | 2040 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2041 | |
c293621b PS |
2042 | /* |
2043 | * Attempt to detect a close/fcntl race and recover by | |
2044 | * releasing the lock that was just acquired. | |
2045 | */ | |
0b2bac2f AV |
2046 | /* |
2047 | * we need that spin_lock here - it prevents reordering between | |
2048 | * update of inode->i_flock and check for it done in close(). | |
2049 | * rcu_read_lock() wouldn't do. | |
2050 | */ | |
2051 | spin_lock(¤t->files->file_lock); | |
2052 | f = fcheck(fd); | |
2053 | spin_unlock(¤t->files->file_lock); | |
2054 | if (!error && f != filp && flock.l_type != F_UNLCK) { | |
c293621b PS |
2055 | flock.l_type = F_UNLCK; |
2056 | goto again; | |
1da177e4 LT |
2057 | } |
2058 | ||
c293621b | 2059 | out: |
1da177e4 LT |
2060 | locks_free_lock(file_lock); |
2061 | return error; | |
2062 | } | |
2063 | ||
2064 | #if BITS_PER_LONG == 32 | |
2065 | /* Report the first existing lock that would conflict with l. | |
2066 | * This implements the F_GETLK command of fcntl(). | |
2067 | */ | |
2068 | int fcntl_getlk64(struct file *filp, struct flock64 __user *l) | |
2069 | { | |
9d6a8c5c | 2070 | struct file_lock file_lock; |
1da177e4 LT |
2071 | struct flock64 flock; |
2072 | int error; | |
2073 | ||
2074 | error = -EFAULT; | |
2075 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2076 | goto out; | |
2077 | error = -EINVAL; | |
2078 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
2079 | goto out; | |
2080 | ||
2081 | error = flock64_to_posix_lock(filp, &file_lock, &flock); | |
2082 | if (error) | |
2083 | goto out; | |
2084 | ||
3ee17abd BF |
2085 | error = vfs_test_lock(filp, &file_lock); |
2086 | if (error) | |
2087 | goto out; | |
2088 | ||
9d6a8c5c ME |
2089 | flock.l_type = file_lock.fl_type; |
2090 | if (file_lock.fl_type != F_UNLCK) | |
2091 | posix_lock_to_flock64(&flock, &file_lock); | |
2092 | ||
1da177e4 LT |
2093 | error = -EFAULT; |
2094 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
2095 | error = 0; | |
2096 | ||
2097 | out: | |
2098 | return error; | |
2099 | } | |
2100 | ||
2101 | /* Apply the lock described by l to an open file descriptor. | |
2102 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2103 | */ | |
c293621b PS |
2104 | int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, |
2105 | struct flock64 __user *l) | |
1da177e4 LT |
2106 | { |
2107 | struct file_lock *file_lock = locks_alloc_lock(); | |
2108 | struct flock64 flock; | |
2109 | struct inode *inode; | |
0b2bac2f | 2110 | struct file *f; |
1da177e4 LT |
2111 | int error; |
2112 | ||
2113 | if (file_lock == NULL) | |
2114 | return -ENOLCK; | |
2115 | ||
2116 | /* | |
2117 | * This might block, so we do it before checking the inode. | |
2118 | */ | |
2119 | error = -EFAULT; | |
2120 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2121 | goto out; | |
2122 | ||
496ad9aa | 2123 | inode = file_inode(filp); |
1da177e4 LT |
2124 | |
2125 | /* Don't allow mandatory locks on files that may be memory mapped | |
2126 | * and shared. | |
2127 | */ | |
a16877ca | 2128 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
2129 | error = -EAGAIN; |
2130 | goto out; | |
2131 | } | |
2132 | ||
c293621b | 2133 | again: |
1da177e4 LT |
2134 | error = flock64_to_posix_lock(filp, file_lock, &flock); |
2135 | if (error) | |
2136 | goto out; | |
2137 | if (cmd == F_SETLKW64) { | |
2138 | file_lock->fl_flags |= FL_SLEEP; | |
2139 | } | |
2140 | ||
b648a6de | 2141 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2142 | |
c293621b PS |
2143 | /* |
2144 | * Attempt to detect a close/fcntl race and recover by | |
2145 | * releasing the lock that was just acquired. | |
2146 | */ | |
0b2bac2f AV |
2147 | spin_lock(¤t->files->file_lock); |
2148 | f = fcheck(fd); | |
2149 | spin_unlock(¤t->files->file_lock); | |
2150 | if (!error && f != filp && flock.l_type != F_UNLCK) { | |
c293621b PS |
2151 | flock.l_type = F_UNLCK; |
2152 | goto again; | |
1da177e4 LT |
2153 | } |
2154 | ||
2155 | out: | |
2156 | locks_free_lock(file_lock); | |
2157 | return error; | |
2158 | } | |
2159 | #endif /* BITS_PER_LONG == 32 */ | |
2160 | ||
2161 | /* | |
2162 | * This function is called when the file is being removed | |
2163 | * from the task's fd array. POSIX locks belonging to this task | |
2164 | * are deleted at this time. | |
2165 | */ | |
2166 | void locks_remove_posix(struct file *filp, fl_owner_t owner) | |
2167 | { | |
ff7b86b8 | 2168 | struct file_lock lock; |
1da177e4 LT |
2169 | |
2170 | /* | |
2171 | * If there are no locks held on this file, we don't need to call | |
2172 | * posix_lock_file(). Another process could be setting a lock on this | |
2173 | * file at the same time, but we wouldn't remove that lock anyway. | |
2174 | */ | |
496ad9aa | 2175 | if (!file_inode(filp)->i_flock) |
1da177e4 LT |
2176 | return; |
2177 | ||
2178 | lock.fl_type = F_UNLCK; | |
75e1fcc0 | 2179 | lock.fl_flags = FL_POSIX | FL_CLOSE; |
1da177e4 LT |
2180 | lock.fl_start = 0; |
2181 | lock.fl_end = OFFSET_MAX; | |
2182 | lock.fl_owner = owner; | |
2183 | lock.fl_pid = current->tgid; | |
2184 | lock.fl_file = filp; | |
2185 | lock.fl_ops = NULL; | |
2186 | lock.fl_lmops = NULL; | |
2187 | ||
150b3934 | 2188 | vfs_lock_file(filp, F_SETLK, &lock, NULL); |
1da177e4 | 2189 | |
1da177e4 LT |
2190 | if (lock.fl_ops && lock.fl_ops->fl_release_private) |
2191 | lock.fl_ops->fl_release_private(&lock); | |
2192 | } | |
2193 | ||
2194 | EXPORT_SYMBOL(locks_remove_posix); | |
2195 | ||
2196 | /* | |
2197 | * This function is called on the last close of an open file. | |
2198 | */ | |
78ed8a13 | 2199 | void locks_remove_file(struct file *filp) |
1da177e4 | 2200 | { |
496ad9aa | 2201 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
2202 | struct file_lock *fl; |
2203 | struct file_lock **before; | |
2204 | ||
2205 | if (!inode->i_flock) | |
2206 | return; | |
2207 | ||
72c2d531 | 2208 | if (filp->f_op->flock) { |
1da177e4 LT |
2209 | struct file_lock fl = { |
2210 | .fl_pid = current->tgid, | |
2211 | .fl_file = filp, | |
2212 | .fl_flags = FL_FLOCK, | |
2213 | .fl_type = F_UNLCK, | |
2214 | .fl_end = OFFSET_MAX, | |
2215 | }; | |
2216 | filp->f_op->flock(filp, F_SETLKW, &fl); | |
80fec4c6 TM |
2217 | if (fl.fl_ops && fl.fl_ops->fl_release_private) |
2218 | fl.fl_ops->fl_release_private(&fl); | |
1da177e4 LT |
2219 | } |
2220 | ||
1c8c601a | 2221 | spin_lock(&inode->i_lock); |
1da177e4 LT |
2222 | before = &inode->i_flock; |
2223 | ||
2224 | while ((fl = *before) != NULL) { | |
2225 | if (fl->fl_file == filp) { | |
1da177e4 LT |
2226 | if (IS_LEASE(fl)) { |
2227 | lease_modify(before, F_UNLCK); | |
2228 | continue; | |
2229 | } | |
8c3cac5e JL |
2230 | |
2231 | /* | |
2232 | * There's a leftover lock on the list of a type that | |
2233 | * we didn't expect to see. Most likely a classic | |
2234 | * POSIX lock that ended up not getting released | |
2235 | * properly, or that raced onto the list somehow. Log | |
2236 | * some info about it and then just remove it from | |
2237 | * the list. | |
2238 | */ | |
2239 | WARN(!IS_FLOCK(fl), | |
2240 | "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n", | |
2241 | MAJOR(inode->i_sb->s_dev), | |
2242 | MINOR(inode->i_sb->s_dev), inode->i_ino, | |
2243 | fl->fl_type, fl->fl_flags, | |
2244 | fl->fl_start, fl->fl_end); | |
2245 | ||
2246 | locks_delete_lock(before); | |
2247 | continue; | |
1da177e4 LT |
2248 | } |
2249 | before = &fl->fl_next; | |
2250 | } | |
1c8c601a | 2251 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2252 | } |
2253 | ||
1da177e4 LT |
2254 | /** |
2255 | * posix_unblock_lock - stop waiting for a file lock | |
1da177e4 LT |
2256 | * @waiter: the lock which was waiting |
2257 | * | |
2258 | * lockd needs to block waiting for locks. | |
2259 | */ | |
64a318ee | 2260 | int |
f891a29f | 2261 | posix_unblock_lock(struct file_lock *waiter) |
1da177e4 | 2262 | { |
64a318ee BF |
2263 | int status = 0; |
2264 | ||
7b2296af | 2265 | spin_lock(&blocked_lock_lock); |
5996a298 | 2266 | if (waiter->fl_next) |
1da177e4 | 2267 | __locks_delete_block(waiter); |
64a318ee BF |
2268 | else |
2269 | status = -ENOENT; | |
7b2296af | 2270 | spin_unlock(&blocked_lock_lock); |
64a318ee | 2271 | return status; |
1da177e4 | 2272 | } |
1da177e4 LT |
2273 | EXPORT_SYMBOL(posix_unblock_lock); |
2274 | ||
9b9d2ab4 ME |
2275 | /** |
2276 | * vfs_cancel_lock - file byte range unblock lock | |
2277 | * @filp: The file to apply the unblock to | |
2278 | * @fl: The lock to be unblocked | |
2279 | * | |
2280 | * Used by lock managers to cancel blocked requests | |
2281 | */ | |
2282 | int vfs_cancel_lock(struct file *filp, struct file_lock *fl) | |
2283 | { | |
72c2d531 | 2284 | if (filp->f_op->lock) |
9b9d2ab4 ME |
2285 | return filp->f_op->lock(filp, F_CANCELLK, fl); |
2286 | return 0; | |
2287 | } | |
2288 | ||
2289 | EXPORT_SYMBOL_GPL(vfs_cancel_lock); | |
2290 | ||
7f8ada98 | 2291 | #ifdef CONFIG_PROC_FS |
d8ba7a36 | 2292 | #include <linux/proc_fs.h> |
7f8ada98 PE |
2293 | #include <linux/seq_file.h> |
2294 | ||
7012b02a JL |
2295 | struct locks_iterator { |
2296 | int li_cpu; | |
2297 | loff_t li_pos; | |
2298 | }; | |
2299 | ||
7f8ada98 | 2300 | static void lock_get_status(struct seq_file *f, struct file_lock *fl, |
99dc8292 | 2301 | loff_t id, char *pfx) |
1da177e4 LT |
2302 | { |
2303 | struct inode *inode = NULL; | |
ab1f1611 VG |
2304 | unsigned int fl_pid; |
2305 | ||
2306 | if (fl->fl_nspid) | |
6c5f3e7b | 2307 | fl_pid = pid_vnr(fl->fl_nspid); |
ab1f1611 VG |
2308 | else |
2309 | fl_pid = fl->fl_pid; | |
1da177e4 LT |
2310 | |
2311 | if (fl->fl_file != NULL) | |
496ad9aa | 2312 | inode = file_inode(fl->fl_file); |
1da177e4 | 2313 | |
99dc8292 | 2314 | seq_printf(f, "%lld:%s ", id, pfx); |
1da177e4 | 2315 | if (IS_POSIX(fl)) { |
7f8ada98 | 2316 | seq_printf(f, "%6s %s ", |
1da177e4 LT |
2317 | (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ", |
2318 | (inode == NULL) ? "*NOINODE*" : | |
a16877ca | 2319 | mandatory_lock(inode) ? "MANDATORY" : "ADVISORY "); |
1da177e4 LT |
2320 | } else if (IS_FLOCK(fl)) { |
2321 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2322 | seq_printf(f, "FLOCK MSNFS "); |
1da177e4 | 2323 | } else { |
7f8ada98 | 2324 | seq_printf(f, "FLOCK ADVISORY "); |
1da177e4 LT |
2325 | } |
2326 | } else if (IS_LEASE(fl)) { | |
7f8ada98 | 2327 | seq_printf(f, "LEASE "); |
ab83fa4b | 2328 | if (lease_breaking(fl)) |
7f8ada98 | 2329 | seq_printf(f, "BREAKING "); |
1da177e4 | 2330 | else if (fl->fl_file) |
7f8ada98 | 2331 | seq_printf(f, "ACTIVE "); |
1da177e4 | 2332 | else |
7f8ada98 | 2333 | seq_printf(f, "BREAKER "); |
1da177e4 | 2334 | } else { |
7f8ada98 | 2335 | seq_printf(f, "UNKNOWN UNKNOWN "); |
1da177e4 LT |
2336 | } |
2337 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2338 | seq_printf(f, "%s ", |
1da177e4 LT |
2339 | (fl->fl_type & LOCK_READ) |
2340 | ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ " | |
2341 | : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE "); | |
2342 | } else { | |
7f8ada98 | 2343 | seq_printf(f, "%s ", |
ab83fa4b | 2344 | (lease_breaking(fl)) |
0ee5c6d6 JL |
2345 | ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ " |
2346 | : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ "); | |
1da177e4 LT |
2347 | } |
2348 | if (inode) { | |
2349 | #ifdef WE_CAN_BREAK_LSLK_NOW | |
ab1f1611 | 2350 | seq_printf(f, "%d %s:%ld ", fl_pid, |
1da177e4 LT |
2351 | inode->i_sb->s_id, inode->i_ino); |
2352 | #else | |
2353 | /* userspace relies on this representation of dev_t ;-( */ | |
ab1f1611 | 2354 | seq_printf(f, "%d %02x:%02x:%ld ", fl_pid, |
1da177e4 LT |
2355 | MAJOR(inode->i_sb->s_dev), |
2356 | MINOR(inode->i_sb->s_dev), inode->i_ino); | |
2357 | #endif | |
2358 | } else { | |
ab1f1611 | 2359 | seq_printf(f, "%d <none>:0 ", fl_pid); |
1da177e4 LT |
2360 | } |
2361 | if (IS_POSIX(fl)) { | |
2362 | if (fl->fl_end == OFFSET_MAX) | |
7f8ada98 | 2363 | seq_printf(f, "%Ld EOF\n", fl->fl_start); |
1da177e4 | 2364 | else |
7f8ada98 | 2365 | seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end); |
1da177e4 | 2366 | } else { |
7f8ada98 | 2367 | seq_printf(f, "0 EOF\n"); |
1da177e4 LT |
2368 | } |
2369 | } | |
2370 | ||
7f8ada98 | 2371 | static int locks_show(struct seq_file *f, void *v) |
1da177e4 | 2372 | { |
7012b02a | 2373 | struct locks_iterator *iter = f->private; |
7f8ada98 | 2374 | struct file_lock *fl, *bfl; |
1da177e4 | 2375 | |
139ca04e | 2376 | fl = hlist_entry(v, struct file_lock, fl_link); |
1da177e4 | 2377 | |
7012b02a | 2378 | lock_get_status(f, fl, iter->li_pos, ""); |
1da177e4 | 2379 | |
7f8ada98 | 2380 | list_for_each_entry(bfl, &fl->fl_block, fl_block) |
7012b02a | 2381 | lock_get_status(f, bfl, iter->li_pos, " ->"); |
094f2825 | 2382 | |
7f8ada98 PE |
2383 | return 0; |
2384 | } | |
1da177e4 | 2385 | |
7f8ada98 | 2386 | static void *locks_start(struct seq_file *f, loff_t *pos) |
b03dfdec | 2387 | __acquires(&blocked_lock_lock) |
7f8ada98 | 2388 | { |
7012b02a | 2389 | struct locks_iterator *iter = f->private; |
99dc8292 | 2390 | |
7012b02a JL |
2391 | iter->li_pos = *pos + 1; |
2392 | lg_global_lock(&file_lock_lglock); | |
7b2296af | 2393 | spin_lock(&blocked_lock_lock); |
7012b02a | 2394 | return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos); |
7f8ada98 | 2395 | } |
1da177e4 | 2396 | |
7f8ada98 PE |
2397 | static void *locks_next(struct seq_file *f, void *v, loff_t *pos) |
2398 | { | |
7012b02a JL |
2399 | struct locks_iterator *iter = f->private; |
2400 | ||
2401 | ++iter->li_pos; | |
2402 | return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos); | |
7f8ada98 | 2403 | } |
1da177e4 | 2404 | |
7f8ada98 | 2405 | static void locks_stop(struct seq_file *f, void *v) |
b03dfdec | 2406 | __releases(&blocked_lock_lock) |
7f8ada98 | 2407 | { |
7b2296af | 2408 | spin_unlock(&blocked_lock_lock); |
7012b02a | 2409 | lg_global_unlock(&file_lock_lglock); |
1da177e4 LT |
2410 | } |
2411 | ||
d8ba7a36 | 2412 | static const struct seq_operations locks_seq_operations = { |
7f8ada98 PE |
2413 | .start = locks_start, |
2414 | .next = locks_next, | |
2415 | .stop = locks_stop, | |
2416 | .show = locks_show, | |
2417 | }; | |
d8ba7a36 AD |
2418 | |
2419 | static int locks_open(struct inode *inode, struct file *filp) | |
2420 | { | |
7012b02a JL |
2421 | return seq_open_private(filp, &locks_seq_operations, |
2422 | sizeof(struct locks_iterator)); | |
d8ba7a36 AD |
2423 | } |
2424 | ||
2425 | static const struct file_operations proc_locks_operations = { | |
2426 | .open = locks_open, | |
2427 | .read = seq_read, | |
2428 | .llseek = seq_lseek, | |
99dc8292 | 2429 | .release = seq_release_private, |
d8ba7a36 AD |
2430 | }; |
2431 | ||
2432 | static int __init proc_locks_init(void) | |
2433 | { | |
2434 | proc_create("locks", 0, NULL, &proc_locks_operations); | |
2435 | return 0; | |
2436 | } | |
2437 | module_init(proc_locks_init); | |
7f8ada98 PE |
2438 | #endif |
2439 | ||
1da177e4 LT |
2440 | /** |
2441 | * lock_may_read - checks that the region is free of locks | |
2442 | * @inode: the inode that is being read | |
2443 | * @start: the first byte to read | |
2444 | * @len: the number of bytes to read | |
2445 | * | |
2446 | * Emulates Windows locking requirements. Whole-file | |
2447 | * mandatory locks (share modes) can prohibit a read and | |
2448 | * byte-range POSIX locks can prohibit a read if they overlap. | |
2449 | * | |
2450 | * N.B. this function is only ever called | |
2451 | * from knfsd and ownership of locks is never checked. | |
2452 | */ | |
2453 | int lock_may_read(struct inode *inode, loff_t start, unsigned long len) | |
2454 | { | |
2455 | struct file_lock *fl; | |
2456 | int result = 1; | |
1c8c601a JL |
2457 | |
2458 | spin_lock(&inode->i_lock); | |
1da177e4 LT |
2459 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
2460 | if (IS_POSIX(fl)) { | |
2461 | if (fl->fl_type == F_RDLCK) | |
2462 | continue; | |
2463 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2464 | continue; | |
2465 | } else if (IS_FLOCK(fl)) { | |
2466 | if (!(fl->fl_type & LOCK_MAND)) | |
2467 | continue; | |
2468 | if (fl->fl_type & LOCK_READ) | |
2469 | continue; | |
2470 | } else | |
2471 | continue; | |
2472 | result = 0; | |
2473 | break; | |
2474 | } | |
1c8c601a | 2475 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2476 | return result; |
2477 | } | |
2478 | ||
2479 | EXPORT_SYMBOL(lock_may_read); | |
2480 | ||
2481 | /** | |
2482 | * lock_may_write - checks that the region is free of locks | |
2483 | * @inode: the inode that is being written | |
2484 | * @start: the first byte to write | |
2485 | * @len: the number of bytes to write | |
2486 | * | |
2487 | * Emulates Windows locking requirements. Whole-file | |
2488 | * mandatory locks (share modes) can prohibit a write and | |
2489 | * byte-range POSIX locks can prohibit a write if they overlap. | |
2490 | * | |
2491 | * N.B. this function is only ever called | |
2492 | * from knfsd and ownership of locks is never checked. | |
2493 | */ | |
2494 | int lock_may_write(struct inode *inode, loff_t start, unsigned long len) | |
2495 | { | |
2496 | struct file_lock *fl; | |
2497 | int result = 1; | |
1c8c601a JL |
2498 | |
2499 | spin_lock(&inode->i_lock); | |
1da177e4 LT |
2500 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
2501 | if (IS_POSIX(fl)) { | |
2502 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2503 | continue; | |
2504 | } else if (IS_FLOCK(fl)) { | |
2505 | if (!(fl->fl_type & LOCK_MAND)) | |
2506 | continue; | |
2507 | if (fl->fl_type & LOCK_WRITE) | |
2508 | continue; | |
2509 | } else | |
2510 | continue; | |
2511 | result = 0; | |
2512 | break; | |
2513 | } | |
1c8c601a | 2514 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2515 | return result; |
2516 | } | |
2517 | ||
2518 | EXPORT_SYMBOL(lock_may_write); | |
2519 | ||
1da177e4 LT |
2520 | static int __init filelock_init(void) |
2521 | { | |
7012b02a JL |
2522 | int i; |
2523 | ||
1da177e4 | 2524 | filelock_cache = kmem_cache_create("file_lock_cache", |
ee19cc40 MS |
2525 | sizeof(struct file_lock), 0, SLAB_PANIC, NULL); |
2526 | ||
7012b02a JL |
2527 | lg_lock_init(&file_lock_lglock, "file_lock_lglock"); |
2528 | ||
2529 | for_each_possible_cpu(i) | |
2530 | INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i)); | |
2531 | ||
1da177e4 LT |
2532 | return 0; |
2533 | } | |
2534 | ||
2535 | core_initcall(filelock_init); |