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)) |
cff2fce5 | 138 | #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK) |
1da177e4 | 139 | |
ab83fa4b BF |
140 | static bool lease_breaking(struct file_lock *fl) |
141 | { | |
778fc546 BF |
142 | return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING); |
143 | } | |
144 | ||
145 | static int target_leasetype(struct file_lock *fl) | |
146 | { | |
147 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
148 | return F_UNLCK; | |
149 | if (fl->fl_flags & FL_DOWNGRADE_PENDING) | |
150 | return F_RDLCK; | |
151 | return fl->fl_type; | |
ab83fa4b BF |
152 | } |
153 | ||
1da177e4 LT |
154 | int leases_enable = 1; |
155 | int lease_break_time = 45; | |
156 | ||
157 | #define for_each_lock(inode, lockp) \ | |
158 | for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) | |
159 | ||
1c8c601a | 160 | /* |
7012b02a JL |
161 | * The global file_lock_list is only used for displaying /proc/locks, so we |
162 | * keep a list on each CPU, with each list protected by its own spinlock via | |
163 | * the file_lock_lglock. Note that alterations to the list also require that | |
164 | * the relevant i_lock is held. | |
1c8c601a | 165 | */ |
7012b02a JL |
166 | DEFINE_STATIC_LGLOCK(file_lock_lglock); |
167 | static DEFINE_PER_CPU(struct hlist_head, file_lock_list); | |
88974691 | 168 | |
1c8c601a | 169 | /* |
48f74186 | 170 | * The blocked_hash is used to find POSIX lock loops for deadlock detection. |
7b2296af | 171 | * It is protected by blocked_lock_lock. |
48f74186 JL |
172 | * |
173 | * We hash locks by lockowner in order to optimize searching for the lock a | |
174 | * particular lockowner is waiting on. | |
175 | * | |
176 | * FIXME: make this value scale via some heuristic? We generally will want more | |
177 | * buckets when we have more lockowners holding locks, but that's a little | |
178 | * difficult to determine without knowing what the workload will look like. | |
1c8c601a | 179 | */ |
48f74186 JL |
180 | #define BLOCKED_HASH_BITS 7 |
181 | static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); | |
88974691 | 182 | |
1c8c601a | 183 | /* |
7b2296af JL |
184 | * This lock protects the blocked_hash. Generally, if you're accessing it, you |
185 | * want to be holding this lock. | |
1c8c601a JL |
186 | * |
187 | * In addition, it also protects the fl->fl_block list, and the fl->fl_next | |
188 | * pointer for file_lock structures that are acting as lock requests (in | |
189 | * contrast to those that are acting as records of acquired locks). | |
190 | * | |
191 | * Note that when we acquire this lock in order to change the above fields, | |
192 | * we often hold the i_lock as well. In certain cases, when reading the fields | |
193 | * protected by this lock, we can skip acquiring it iff we already hold the | |
194 | * i_lock. | |
195 | * | |
196 | * In particular, adding an entry to the fl_block list requires that you hold | |
197 | * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting | |
198 | * an entry from the list however only requires the file_lock_lock. | |
199 | */ | |
7b2296af | 200 | static DEFINE_SPINLOCK(blocked_lock_lock); |
1da177e4 | 201 | |
e18b890b | 202 | static struct kmem_cache *filelock_cache __read_mostly; |
1da177e4 | 203 | |
ee19cc40 | 204 | static void locks_init_lock_heads(struct file_lock *fl) |
a51cb91d | 205 | { |
139ca04e | 206 | INIT_HLIST_NODE(&fl->fl_link); |
ee19cc40 MS |
207 | INIT_LIST_HEAD(&fl->fl_block); |
208 | init_waitqueue_head(&fl->fl_wait); | |
a51cb91d MS |
209 | } |
210 | ||
1da177e4 | 211 | /* Allocate an empty lock structure. */ |
c5b1f0d9 | 212 | struct file_lock *locks_alloc_lock(void) |
1da177e4 | 213 | { |
ee19cc40 | 214 | struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL); |
a51cb91d MS |
215 | |
216 | if (fl) | |
ee19cc40 | 217 | locks_init_lock_heads(fl); |
a51cb91d MS |
218 | |
219 | return fl; | |
1da177e4 | 220 | } |
c5b1f0d9 | 221 | EXPORT_SYMBOL_GPL(locks_alloc_lock); |
1da177e4 | 222 | |
a9e61e25 | 223 | void locks_release_private(struct file_lock *fl) |
47831f35 TM |
224 | { |
225 | if (fl->fl_ops) { | |
226 | if (fl->fl_ops->fl_release_private) | |
227 | fl->fl_ops->fl_release_private(fl); | |
228 | fl->fl_ops = NULL; | |
229 | } | |
068535f1 | 230 | fl->fl_lmops = NULL; |
47831f35 TM |
231 | |
232 | } | |
a9e61e25 | 233 | EXPORT_SYMBOL_GPL(locks_release_private); |
47831f35 | 234 | |
1da177e4 | 235 | /* Free a lock which is not in use. */ |
05fa3135 | 236 | void locks_free_lock(struct file_lock *fl) |
1da177e4 | 237 | { |
5ce29646 MS |
238 | BUG_ON(waitqueue_active(&fl->fl_wait)); |
239 | BUG_ON(!list_empty(&fl->fl_block)); | |
139ca04e | 240 | BUG_ON(!hlist_unhashed(&fl->fl_link)); |
1da177e4 | 241 | |
47831f35 | 242 | locks_release_private(fl); |
1da177e4 LT |
243 | kmem_cache_free(filelock_cache, fl); |
244 | } | |
05fa3135 | 245 | EXPORT_SYMBOL(locks_free_lock); |
1da177e4 LT |
246 | |
247 | void locks_init_lock(struct file_lock *fl) | |
248 | { | |
ee19cc40 MS |
249 | memset(fl, 0, sizeof(struct file_lock)); |
250 | locks_init_lock_heads(fl); | |
1da177e4 LT |
251 | } |
252 | ||
253 | EXPORT_SYMBOL(locks_init_lock); | |
254 | ||
47831f35 TM |
255 | static void locks_copy_private(struct file_lock *new, struct file_lock *fl) |
256 | { | |
257 | if (fl->fl_ops) { | |
258 | if (fl->fl_ops->fl_copy_lock) | |
259 | fl->fl_ops->fl_copy_lock(new, fl); | |
260 | new->fl_ops = fl->fl_ops; | |
261 | } | |
bb8430a2 | 262 | if (fl->fl_lmops) |
47831f35 | 263 | new->fl_lmops = fl->fl_lmops; |
47831f35 TM |
264 | } |
265 | ||
1da177e4 LT |
266 | /* |
267 | * Initialize a new lock from an existing file_lock structure. | |
268 | */ | |
1a747ee0 | 269 | void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl) |
1da177e4 LT |
270 | { |
271 | new->fl_owner = fl->fl_owner; | |
272 | new->fl_pid = fl->fl_pid; | |
0996905f | 273 | new->fl_file = NULL; |
1da177e4 LT |
274 | new->fl_flags = fl->fl_flags; |
275 | new->fl_type = fl->fl_type; | |
276 | new->fl_start = fl->fl_start; | |
277 | new->fl_end = fl->fl_end; | |
0996905f TM |
278 | new->fl_ops = NULL; |
279 | new->fl_lmops = NULL; | |
280 | } | |
3dd7b71c | 281 | EXPORT_SYMBOL(__locks_copy_lock); |
0996905f TM |
282 | |
283 | void locks_copy_lock(struct file_lock *new, struct file_lock *fl) | |
284 | { | |
285 | locks_release_private(new); | |
286 | ||
287 | __locks_copy_lock(new, fl); | |
288 | new->fl_file = fl->fl_file; | |
1da177e4 LT |
289 | new->fl_ops = fl->fl_ops; |
290 | new->fl_lmops = fl->fl_lmops; | |
47831f35 TM |
291 | |
292 | locks_copy_private(new, fl); | |
1da177e4 LT |
293 | } |
294 | ||
295 | EXPORT_SYMBOL(locks_copy_lock); | |
296 | ||
297 | static inline int flock_translate_cmd(int cmd) { | |
298 | if (cmd & LOCK_MAND) | |
299 | return cmd & (LOCK_MAND | LOCK_RW); | |
300 | switch (cmd) { | |
301 | case LOCK_SH: | |
302 | return F_RDLCK; | |
303 | case LOCK_EX: | |
304 | return F_WRLCK; | |
305 | case LOCK_UN: | |
306 | return F_UNLCK; | |
307 | } | |
308 | return -EINVAL; | |
309 | } | |
310 | ||
311 | /* Fill in a file_lock structure with an appropriate FLOCK lock. */ | |
312 | static int flock_make_lock(struct file *filp, struct file_lock **lock, | |
313 | unsigned int cmd) | |
314 | { | |
315 | struct file_lock *fl; | |
316 | int type = flock_translate_cmd(cmd); | |
317 | if (type < 0) | |
318 | return type; | |
319 | ||
320 | fl = locks_alloc_lock(); | |
321 | if (fl == NULL) | |
322 | return -ENOMEM; | |
323 | ||
324 | fl->fl_file = filp; | |
130d1f95 | 325 | fl->fl_owner = (fl_owner_t)filp; |
1da177e4 LT |
326 | fl->fl_pid = current->tgid; |
327 | fl->fl_flags = FL_FLOCK; | |
328 | fl->fl_type = type; | |
329 | fl->fl_end = OFFSET_MAX; | |
330 | ||
331 | *lock = fl; | |
332 | return 0; | |
333 | } | |
334 | ||
0ec4f431 | 335 | static int assign_type(struct file_lock *fl, long type) |
1da177e4 LT |
336 | { |
337 | switch (type) { | |
338 | case F_RDLCK: | |
339 | case F_WRLCK: | |
340 | case F_UNLCK: | |
341 | fl->fl_type = type; | |
342 | break; | |
343 | default: | |
344 | return -EINVAL; | |
345 | } | |
346 | return 0; | |
347 | } | |
348 | ||
ef12e72a BF |
349 | static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, |
350 | struct flock64 *l) | |
1da177e4 | 351 | { |
1da177e4 | 352 | switch (l->l_whence) { |
f5579f8c | 353 | case SEEK_SET: |
ef12e72a | 354 | fl->fl_start = 0; |
1da177e4 | 355 | break; |
f5579f8c | 356 | case SEEK_CUR: |
ef12e72a | 357 | fl->fl_start = filp->f_pos; |
1da177e4 | 358 | break; |
f5579f8c | 359 | case SEEK_END: |
ef12e72a | 360 | fl->fl_start = i_size_read(file_inode(filp)); |
1da177e4 LT |
361 | break; |
362 | default: | |
363 | return -EINVAL; | |
364 | } | |
ef12e72a BF |
365 | if (l->l_start > OFFSET_MAX - fl->fl_start) |
366 | return -EOVERFLOW; | |
367 | fl->fl_start += l->l_start; | |
368 | if (fl->fl_start < 0) | |
369 | return -EINVAL; | |
1da177e4 LT |
370 | |
371 | /* POSIX-1996 leaves the case l->l_len < 0 undefined; | |
372 | POSIX-2001 defines it. */ | |
4c780a46 | 373 | if (l->l_len > 0) { |
ef12e72a BF |
374 | if (l->l_len - 1 > OFFSET_MAX - fl->fl_start) |
375 | return -EOVERFLOW; | |
376 | fl->fl_end = fl->fl_start + l->l_len - 1; | |
377 | ||
4c780a46 | 378 | } else if (l->l_len < 0) { |
ef12e72a | 379 | if (fl->fl_start + l->l_len < 0) |
4c780a46 | 380 | return -EINVAL; |
ef12e72a BF |
381 | fl->fl_end = fl->fl_start - 1; |
382 | fl->fl_start += l->l_len; | |
383 | } else | |
384 | fl->fl_end = OFFSET_MAX; | |
385 | ||
1da177e4 LT |
386 | fl->fl_owner = current->files; |
387 | fl->fl_pid = current->tgid; | |
388 | fl->fl_file = filp; | |
389 | fl->fl_flags = FL_POSIX; | |
390 | fl->fl_ops = NULL; | |
391 | fl->fl_lmops = NULL; | |
392 | ||
393 | return assign_type(fl, l->l_type); | |
394 | } | |
395 | ||
ef12e72a BF |
396 | /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX |
397 | * style lock. | |
398 | */ | |
399 | static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, | |
400 | struct flock *l) | |
1da177e4 | 401 | { |
ef12e72a BF |
402 | struct flock64 ll = { |
403 | .l_type = l->l_type, | |
404 | .l_whence = l->l_whence, | |
405 | .l_start = l->l_start, | |
406 | .l_len = l->l_len, | |
407 | }; | |
408 | ||
409 | return flock64_to_posix_lock(filp, fl, &ll); | |
1da177e4 | 410 | } |
1da177e4 LT |
411 | |
412 | /* default lease lock manager operations */ | |
413 | static void lease_break_callback(struct file_lock *fl) | |
414 | { | |
415 | kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG); | |
416 | } | |
417 | ||
7b021967 | 418 | static const struct lock_manager_operations lease_manager_ops = { |
8fb47a4f | 419 | .lm_break = lease_break_callback, |
8fb47a4f | 420 | .lm_change = lease_modify, |
1da177e4 LT |
421 | }; |
422 | ||
423 | /* | |
424 | * Initialize a lease, use the default lock manager operations | |
425 | */ | |
0ec4f431 | 426 | static int lease_init(struct file *filp, long type, struct file_lock *fl) |
1da177e4 | 427 | { |
75dff55a TM |
428 | if (assign_type(fl, type) != 0) |
429 | return -EINVAL; | |
430 | ||
130d1f95 | 431 | fl->fl_owner = (fl_owner_t)filp; |
1da177e4 LT |
432 | fl->fl_pid = current->tgid; |
433 | ||
434 | fl->fl_file = filp; | |
435 | fl->fl_flags = FL_LEASE; | |
1da177e4 LT |
436 | fl->fl_start = 0; |
437 | fl->fl_end = OFFSET_MAX; | |
438 | fl->fl_ops = NULL; | |
439 | fl->fl_lmops = &lease_manager_ops; | |
440 | return 0; | |
441 | } | |
442 | ||
443 | /* Allocate a file_lock initialised to this type of lease */ | |
0ec4f431 | 444 | static struct file_lock *lease_alloc(struct file *filp, long type) |
1da177e4 LT |
445 | { |
446 | struct file_lock *fl = locks_alloc_lock(); | |
75dff55a | 447 | int error = -ENOMEM; |
1da177e4 LT |
448 | |
449 | if (fl == NULL) | |
e32b8ee2 | 450 | return ERR_PTR(error); |
1da177e4 LT |
451 | |
452 | error = lease_init(filp, type, fl); | |
75dff55a TM |
453 | if (error) { |
454 | locks_free_lock(fl); | |
e32b8ee2 | 455 | return ERR_PTR(error); |
75dff55a | 456 | } |
e32b8ee2 | 457 | return fl; |
1da177e4 LT |
458 | } |
459 | ||
460 | /* Check if two locks overlap each other. | |
461 | */ | |
462 | static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2) | |
463 | { | |
464 | return ((fl1->fl_end >= fl2->fl_start) && | |
465 | (fl2->fl_end >= fl1->fl_start)); | |
466 | } | |
467 | ||
468 | /* | |
469 | * Check whether two locks have the same owner. | |
470 | */ | |
33443c42 | 471 | static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) |
1da177e4 | 472 | { |
8fb47a4f | 473 | if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner) |
1da177e4 | 474 | return fl2->fl_lmops == fl1->fl_lmops && |
8fb47a4f | 475 | fl1->fl_lmops->lm_compare_owner(fl1, fl2); |
1da177e4 LT |
476 | return fl1->fl_owner == fl2->fl_owner; |
477 | } | |
478 | ||
7012b02a | 479 | /* Must be called with the i_lock held! */ |
6ca10ed8 | 480 | static void locks_insert_global_locks(struct file_lock *fl) |
88974691 | 481 | { |
7012b02a JL |
482 | lg_local_lock(&file_lock_lglock); |
483 | fl->fl_link_cpu = smp_processor_id(); | |
484 | hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list)); | |
485 | lg_local_unlock(&file_lock_lglock); | |
88974691 JL |
486 | } |
487 | ||
7012b02a | 488 | /* Must be called with the i_lock held! */ |
6ca10ed8 | 489 | static void locks_delete_global_locks(struct file_lock *fl) |
88974691 | 490 | { |
7012b02a JL |
491 | /* |
492 | * Avoid taking lock if already unhashed. This is safe since this check | |
493 | * is done while holding the i_lock, and new insertions into the list | |
494 | * also require that it be held. | |
495 | */ | |
496 | if (hlist_unhashed(&fl->fl_link)) | |
497 | return; | |
498 | lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu); | |
139ca04e | 499 | hlist_del_init(&fl->fl_link); |
7012b02a | 500 | lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu); |
88974691 JL |
501 | } |
502 | ||
3999e493 JL |
503 | static unsigned long |
504 | posix_owner_key(struct file_lock *fl) | |
505 | { | |
506 | if (fl->fl_lmops && fl->fl_lmops->lm_owner_key) | |
507 | return fl->fl_lmops->lm_owner_key(fl); | |
508 | return (unsigned long)fl->fl_owner; | |
509 | } | |
510 | ||
6ca10ed8 | 511 | static void locks_insert_global_blocked(struct file_lock *waiter) |
88974691 | 512 | { |
3999e493 | 513 | hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter)); |
88974691 JL |
514 | } |
515 | ||
6ca10ed8 | 516 | static void locks_delete_global_blocked(struct file_lock *waiter) |
88974691 | 517 | { |
48f74186 | 518 | hash_del(&waiter->fl_link); |
88974691 JL |
519 | } |
520 | ||
1da177e4 LT |
521 | /* Remove waiter from blocker's block list. |
522 | * When blocker ends up pointing to itself then the list is empty. | |
1c8c601a | 523 | * |
7b2296af | 524 | * Must be called with blocked_lock_lock held. |
1da177e4 | 525 | */ |
33443c42 | 526 | static void __locks_delete_block(struct file_lock *waiter) |
1da177e4 | 527 | { |
88974691 | 528 | locks_delete_global_blocked(waiter); |
1da177e4 | 529 | list_del_init(&waiter->fl_block); |
1da177e4 LT |
530 | waiter->fl_next = NULL; |
531 | } | |
532 | ||
1a9e64a7 | 533 | static void locks_delete_block(struct file_lock *waiter) |
1da177e4 | 534 | { |
7b2296af | 535 | spin_lock(&blocked_lock_lock); |
1da177e4 | 536 | __locks_delete_block(waiter); |
7b2296af | 537 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
538 | } |
539 | ||
540 | /* Insert waiter into blocker's block list. | |
541 | * We use a circular list so that processes can be easily woken up in | |
542 | * the order they blocked. The documentation doesn't require this but | |
543 | * it seems like the reasonable thing to do. | |
1c8c601a | 544 | * |
7b2296af | 545 | * Must be called with both the i_lock and blocked_lock_lock held. The fl_block |
46dad760 | 546 | * list itself is protected by the blocked_lock_lock, but by ensuring that the |
7b2296af | 547 | * i_lock is also held on insertions we can avoid taking the blocked_lock_lock |
4e8c765d | 548 | * in some cases when we see that the fl_block list is empty. |
1da177e4 | 549 | */ |
1c8c601a JL |
550 | static void __locks_insert_block(struct file_lock *blocker, |
551 | struct file_lock *waiter) | |
1da177e4 | 552 | { |
6dc0fe8f | 553 | BUG_ON(!list_empty(&waiter->fl_block)); |
1da177e4 | 554 | waiter->fl_next = blocker; |
88974691 | 555 | list_add_tail(&waiter->fl_block, &blocker->fl_block); |
cff2fce5 | 556 | if (IS_POSIX(blocker) && !IS_OFDLCK(blocker)) |
1c8c601a JL |
557 | locks_insert_global_blocked(waiter); |
558 | } | |
559 | ||
560 | /* Must be called with i_lock held. */ | |
561 | static void locks_insert_block(struct file_lock *blocker, | |
562 | struct file_lock *waiter) | |
563 | { | |
7b2296af | 564 | spin_lock(&blocked_lock_lock); |
1c8c601a | 565 | __locks_insert_block(blocker, waiter); |
7b2296af | 566 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
567 | } |
568 | ||
1cb36012 JL |
569 | /* |
570 | * Wake up processes blocked waiting for blocker. | |
571 | * | |
1c8c601a | 572 | * Must be called with the inode->i_lock held! |
1da177e4 LT |
573 | */ |
574 | static void locks_wake_up_blocks(struct file_lock *blocker) | |
575 | { | |
4e8c765d JL |
576 | /* |
577 | * Avoid taking global lock if list is empty. This is safe since new | |
578 | * blocked requests are only added to the list under the i_lock, and | |
579 | * the i_lock is always held here. Note that removal from the fl_block | |
580 | * list does not require the i_lock, so we must recheck list_empty() | |
7b2296af | 581 | * after acquiring the blocked_lock_lock. |
4e8c765d JL |
582 | */ |
583 | if (list_empty(&blocker->fl_block)) | |
584 | return; | |
585 | ||
7b2296af | 586 | spin_lock(&blocked_lock_lock); |
1da177e4 | 587 | while (!list_empty(&blocker->fl_block)) { |
f0c1cd0e PE |
588 | struct file_lock *waiter; |
589 | ||
590 | waiter = list_first_entry(&blocker->fl_block, | |
1da177e4 LT |
591 | struct file_lock, fl_block); |
592 | __locks_delete_block(waiter); | |
8fb47a4f BF |
593 | if (waiter->fl_lmops && waiter->fl_lmops->lm_notify) |
594 | waiter->fl_lmops->lm_notify(waiter); | |
1da177e4 LT |
595 | else |
596 | wake_up(&waiter->fl_wait); | |
597 | } | |
7b2296af | 598 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
599 | } |
600 | ||
601 | /* Insert file lock fl into an inode's lock list at the position indicated | |
602 | * by pos. At the same time add the lock to the global file lock list. | |
1c8c601a JL |
603 | * |
604 | * Must be called with the i_lock held! | |
1da177e4 LT |
605 | */ |
606 | static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl) | |
607 | { | |
ab1f1611 VG |
608 | fl->fl_nspid = get_pid(task_tgid(current)); |
609 | ||
1da177e4 LT |
610 | /* insert into file's list */ |
611 | fl->fl_next = *pos; | |
612 | *pos = fl; | |
88974691 JL |
613 | |
614 | locks_insert_global_locks(fl); | |
1da177e4 LT |
615 | } |
616 | ||
24cbe784 JL |
617 | /** |
618 | * locks_delete_lock - Delete a lock and then free it. | |
619 | * @thisfl_p: pointer that points to the fl_next field of the previous | |
620 | * inode->i_flock list entry | |
621 | * | |
622 | * Unlink a lock from all lists and free the namespace reference, but don't | |
623 | * free it yet. Wake up processes that are blocked waiting for this lock and | |
624 | * notify the FS that the lock has been cleared. | |
1c8c601a JL |
625 | * |
626 | * Must be called with the i_lock held! | |
1da177e4 | 627 | */ |
24cbe784 | 628 | static void locks_unlink_lock(struct file_lock **thisfl_p) |
1da177e4 LT |
629 | { |
630 | struct file_lock *fl = *thisfl_p; | |
631 | ||
88974691 JL |
632 | locks_delete_global_locks(fl); |
633 | ||
1da177e4 LT |
634 | *thisfl_p = fl->fl_next; |
635 | fl->fl_next = NULL; | |
1da177e4 | 636 | |
ab1f1611 VG |
637 | if (fl->fl_nspid) { |
638 | put_pid(fl->fl_nspid); | |
639 | fl->fl_nspid = NULL; | |
640 | } | |
641 | ||
1da177e4 | 642 | locks_wake_up_blocks(fl); |
24cbe784 JL |
643 | } |
644 | ||
645 | /* | |
646 | * Unlink a lock from all lists and free it. | |
647 | * | |
648 | * Must be called with i_lock held! | |
649 | */ | |
650 | static void locks_delete_lock(struct file_lock **thisfl_p) | |
651 | { | |
652 | struct file_lock *fl = *thisfl_p; | |
653 | ||
654 | locks_unlink_lock(thisfl_p); | |
1da177e4 LT |
655 | locks_free_lock(fl); |
656 | } | |
657 | ||
658 | /* Determine if lock sys_fl blocks lock caller_fl. Common functionality | |
659 | * checks for shared/exclusive status of overlapping locks. | |
660 | */ | |
661 | static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
662 | { | |
663 | if (sys_fl->fl_type == F_WRLCK) | |
664 | return 1; | |
665 | if (caller_fl->fl_type == F_WRLCK) | |
666 | return 1; | |
667 | return 0; | |
668 | } | |
669 | ||
670 | /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific | |
671 | * checking before calling the locks_conflict(). | |
672 | */ | |
673 | static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
674 | { | |
675 | /* POSIX locks owned by the same process do not conflict with | |
676 | * each other. | |
677 | */ | |
678 | if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl)) | |
679 | return (0); | |
680 | ||
681 | /* Check whether they overlap */ | |
682 | if (!locks_overlap(caller_fl, sys_fl)) | |
683 | return 0; | |
684 | ||
685 | return (locks_conflict(caller_fl, sys_fl)); | |
686 | } | |
687 | ||
688 | /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific | |
689 | * checking before calling the locks_conflict(). | |
690 | */ | |
691 | static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl) | |
692 | { | |
693 | /* FLOCK locks referring to the same filp do not conflict with | |
694 | * each other. | |
695 | */ | |
696 | if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file)) | |
697 | return (0); | |
698 | if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND)) | |
699 | return 0; | |
700 | ||
701 | return (locks_conflict(caller_fl, sys_fl)); | |
702 | } | |
703 | ||
6d34ac19 | 704 | void |
9d6a8c5c | 705 | posix_test_lock(struct file *filp, struct file_lock *fl) |
1da177e4 LT |
706 | { |
707 | struct file_lock *cfl; | |
1c8c601a | 708 | struct inode *inode = file_inode(filp); |
1da177e4 | 709 | |
1c8c601a | 710 | spin_lock(&inode->i_lock); |
496ad9aa | 711 | for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) { |
1da177e4 LT |
712 | if (!IS_POSIX(cfl)) |
713 | continue; | |
b842e240 | 714 | if (posix_locks_conflict(fl, cfl)) |
1da177e4 LT |
715 | break; |
716 | } | |
ab1f1611 | 717 | if (cfl) { |
9d6a8c5c | 718 | __locks_copy_lock(fl, cfl); |
ab1f1611 | 719 | if (cfl->fl_nspid) |
6c5f3e7b | 720 | fl->fl_pid = pid_vnr(cfl->fl_nspid); |
ab1f1611 | 721 | } else |
129a84de | 722 | fl->fl_type = F_UNLCK; |
1c8c601a | 723 | spin_unlock(&inode->i_lock); |
6d34ac19 | 724 | return; |
1da177e4 | 725 | } |
1da177e4 LT |
726 | EXPORT_SYMBOL(posix_test_lock); |
727 | ||
b533184f BF |
728 | /* |
729 | * Deadlock detection: | |
730 | * | |
731 | * We attempt to detect deadlocks that are due purely to posix file | |
732 | * locks. | |
1da177e4 | 733 | * |
b533184f BF |
734 | * We assume that a task can be waiting for at most one lock at a time. |
735 | * So for any acquired lock, the process holding that lock may be | |
736 | * waiting on at most one other lock. That lock in turns may be held by | |
737 | * someone waiting for at most one other lock. Given a requested lock | |
738 | * caller_fl which is about to wait for a conflicting lock block_fl, we | |
739 | * follow this chain of waiters to ensure we are not about to create a | |
740 | * cycle. | |
1da177e4 | 741 | * |
b533184f BF |
742 | * Since we do this before we ever put a process to sleep on a lock, we |
743 | * are ensured that there is never a cycle; that is what guarantees that | |
744 | * the while() loop in posix_locks_deadlock() eventually completes. | |
97855b49 | 745 | * |
b533184f BF |
746 | * Note: the above assumption may not be true when handling lock |
747 | * requests from a broken NFS client. It may also fail in the presence | |
748 | * of tasks (such as posix threads) sharing the same open file table. | |
b533184f | 749 | * To handle those cases, we just bail out after a few iterations. |
57b65325 | 750 | * |
cff2fce5 | 751 | * For FL_OFDLCK locks, the owner is the filp, not the files_struct. |
57b65325 JL |
752 | * Because the owner is not even nominally tied to a thread of |
753 | * execution, the deadlock detection below can't reasonably work well. Just | |
754 | * skip it for those. | |
755 | * | |
cff2fce5 | 756 | * In principle, we could do a more limited deadlock detection on FL_OFDLCK |
57b65325 JL |
757 | * locks that just checks for the case where two tasks are attempting to |
758 | * upgrade from read to write locks on the same inode. | |
1da177e4 | 759 | */ |
97855b49 BF |
760 | |
761 | #define MAX_DEADLK_ITERATIONS 10 | |
762 | ||
b533184f BF |
763 | /* Find a lock that the owner of the given block_fl is blocking on. */ |
764 | static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) | |
765 | { | |
766 | struct file_lock *fl; | |
767 | ||
3999e493 | 768 | hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) { |
b533184f BF |
769 | if (posix_same_owner(fl, block_fl)) |
770 | return fl->fl_next; | |
771 | } | |
772 | return NULL; | |
773 | } | |
774 | ||
7b2296af | 775 | /* Must be called with the blocked_lock_lock held! */ |
b0904e14 | 776 | static int posix_locks_deadlock(struct file_lock *caller_fl, |
1da177e4 LT |
777 | struct file_lock *block_fl) |
778 | { | |
97855b49 | 779 | int i = 0; |
1da177e4 | 780 | |
57b65325 JL |
781 | /* |
782 | * This deadlock detector can't reasonably detect deadlocks with | |
cff2fce5 | 783 | * FL_OFDLCK locks, since they aren't owned by a process, per-se. |
57b65325 | 784 | */ |
cff2fce5 | 785 | if (IS_OFDLCK(caller_fl)) |
57b65325 JL |
786 | return 0; |
787 | ||
b533184f BF |
788 | while ((block_fl = what_owner_is_waiting_for(block_fl))) { |
789 | if (i++ > MAX_DEADLK_ITERATIONS) | |
790 | return 0; | |
791 | if (posix_same_owner(caller_fl, block_fl)) | |
792 | return 1; | |
1da177e4 LT |
793 | } |
794 | return 0; | |
795 | } | |
796 | ||
1da177e4 | 797 | /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks |
02888f41 | 798 | * after any leases, but before any posix locks. |
f475ae95 TM |
799 | * |
800 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
801 | * whether or not a lock was successfully freed by testing the return | |
802 | * value for -ENOENT. | |
1da177e4 | 803 | */ |
993dfa87 | 804 | static int flock_lock_file(struct file *filp, struct file_lock *request) |
1da177e4 | 805 | { |
993dfa87 | 806 | struct file_lock *new_fl = NULL; |
1da177e4 | 807 | struct file_lock **before; |
496ad9aa | 808 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
809 | int error = 0; |
810 | int found = 0; | |
811 | ||
b89f4321 | 812 | if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) { |
84d535ad | 813 | new_fl = locks_alloc_lock(); |
b89f4321 AB |
814 | if (!new_fl) |
815 | return -ENOMEM; | |
84d535ad PE |
816 | } |
817 | ||
1c8c601a | 818 | spin_lock(&inode->i_lock); |
b89f4321 AB |
819 | if (request->fl_flags & FL_ACCESS) |
820 | goto find_conflict; | |
821 | ||
1da177e4 LT |
822 | for_each_lock(inode, before) { |
823 | struct file_lock *fl = *before; | |
824 | if (IS_POSIX(fl)) | |
825 | break; | |
826 | if (IS_LEASE(fl)) | |
827 | continue; | |
828 | if (filp != fl->fl_file) | |
829 | continue; | |
993dfa87 | 830 | if (request->fl_type == fl->fl_type) |
1da177e4 LT |
831 | goto out; |
832 | found = 1; | |
833 | locks_delete_lock(before); | |
834 | break; | |
835 | } | |
1da177e4 | 836 | |
f475ae95 TM |
837 | if (request->fl_type == F_UNLCK) { |
838 | if ((request->fl_flags & FL_EXISTS) && !found) | |
839 | error = -ENOENT; | |
993dfa87 | 840 | goto out; |
f475ae95 | 841 | } |
1da177e4 LT |
842 | |
843 | /* | |
844 | * If a higher-priority process was blocked on the old file lock, | |
845 | * give it the opportunity to lock the file. | |
846 | */ | |
b89f4321 | 847 | if (found) { |
1c8c601a | 848 | spin_unlock(&inode->i_lock); |
def01bc5 | 849 | cond_resched(); |
1c8c601a | 850 | spin_lock(&inode->i_lock); |
b89f4321 | 851 | } |
1da177e4 | 852 | |
f07f18dd | 853 | find_conflict: |
1da177e4 LT |
854 | for_each_lock(inode, before) { |
855 | struct file_lock *fl = *before; | |
856 | if (IS_POSIX(fl)) | |
857 | break; | |
858 | if (IS_LEASE(fl)) | |
859 | continue; | |
993dfa87 | 860 | if (!flock_locks_conflict(request, fl)) |
1da177e4 LT |
861 | continue; |
862 | error = -EAGAIN; | |
bde74e4b MS |
863 | if (!(request->fl_flags & FL_SLEEP)) |
864 | goto out; | |
865 | error = FILE_LOCK_DEFERRED; | |
866 | locks_insert_block(fl, request); | |
1da177e4 LT |
867 | goto out; |
868 | } | |
f07f18dd TM |
869 | if (request->fl_flags & FL_ACCESS) |
870 | goto out; | |
993dfa87 | 871 | locks_copy_lock(new_fl, request); |
0e2f6db8 | 872 | locks_insert_lock(before, new_fl); |
993dfa87 | 873 | new_fl = NULL; |
9cedc194 | 874 | error = 0; |
1da177e4 LT |
875 | |
876 | out: | |
1c8c601a | 877 | spin_unlock(&inode->i_lock); |
993dfa87 TM |
878 | if (new_fl) |
879 | locks_free_lock(new_fl); | |
1da177e4 LT |
880 | return error; |
881 | } | |
882 | ||
150b3934 | 883 | static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock) |
1da177e4 LT |
884 | { |
885 | struct file_lock *fl; | |
39005d02 MS |
886 | struct file_lock *new_fl = NULL; |
887 | struct file_lock *new_fl2 = NULL; | |
1da177e4 LT |
888 | struct file_lock *left = NULL; |
889 | struct file_lock *right = NULL; | |
890 | struct file_lock **before; | |
b9746ef8 JL |
891 | int error; |
892 | bool added = false; | |
1da177e4 LT |
893 | |
894 | /* | |
895 | * We may need two file_lock structures for this operation, | |
896 | * so we get them in advance to avoid races. | |
39005d02 MS |
897 | * |
898 | * In some cases we can be sure, that no new locks will be needed | |
1da177e4 | 899 | */ |
39005d02 MS |
900 | if (!(request->fl_flags & FL_ACCESS) && |
901 | (request->fl_type != F_UNLCK || | |
902 | request->fl_start != 0 || request->fl_end != OFFSET_MAX)) { | |
903 | new_fl = locks_alloc_lock(); | |
904 | new_fl2 = locks_alloc_lock(); | |
905 | } | |
1da177e4 | 906 | |
1c8c601a | 907 | spin_lock(&inode->i_lock); |
1cb36012 JL |
908 | /* |
909 | * New lock request. Walk all POSIX locks and look for conflicts. If | |
910 | * there are any, either return error or put the request on the | |
48f74186 | 911 | * blocker's list of waiters and the global blocked_hash. |
1cb36012 | 912 | */ |
1da177e4 LT |
913 | if (request->fl_type != F_UNLCK) { |
914 | for_each_lock(inode, before) { | |
526985b9 | 915 | fl = *before; |
1da177e4 LT |
916 | if (!IS_POSIX(fl)) |
917 | continue; | |
918 | if (!posix_locks_conflict(request, fl)) | |
919 | continue; | |
5842add2 | 920 | if (conflock) |
1a747ee0 | 921 | __locks_copy_lock(conflock, fl); |
1da177e4 LT |
922 | error = -EAGAIN; |
923 | if (!(request->fl_flags & FL_SLEEP)) | |
924 | goto out; | |
1c8c601a JL |
925 | /* |
926 | * Deadlock detection and insertion into the blocked | |
927 | * locks list must be done while holding the same lock! | |
928 | */ | |
1da177e4 | 929 | error = -EDEADLK; |
7b2296af | 930 | spin_lock(&blocked_lock_lock); |
1c8c601a JL |
931 | if (likely(!posix_locks_deadlock(request, fl))) { |
932 | error = FILE_LOCK_DEFERRED; | |
933 | __locks_insert_block(fl, request); | |
934 | } | |
7b2296af | 935 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
936 | goto out; |
937 | } | |
938 | } | |
939 | ||
940 | /* If we're just looking for a conflict, we're done. */ | |
941 | error = 0; | |
942 | if (request->fl_flags & FL_ACCESS) | |
943 | goto out; | |
944 | ||
1da177e4 | 945 | /* |
1da177e4 LT |
946 | * Find the first old lock with the same owner as the new lock. |
947 | */ | |
948 | ||
949 | before = &inode->i_flock; | |
950 | ||
951 | /* First skip locks owned by other processes. */ | |
952 | while ((fl = *before) && (!IS_POSIX(fl) || | |
953 | !posix_same_owner(request, fl))) { | |
954 | before = &fl->fl_next; | |
955 | } | |
956 | ||
1cb36012 | 957 | /* Process locks with this owner. */ |
1da177e4 LT |
958 | while ((fl = *before) && posix_same_owner(request, fl)) { |
959 | /* Detect adjacent or overlapping regions (if same lock type) | |
960 | */ | |
961 | if (request->fl_type == fl->fl_type) { | |
449231d6 OK |
962 | /* In all comparisons of start vs end, use |
963 | * "start - 1" rather than "end + 1". If end | |
964 | * is OFFSET_MAX, end + 1 will become negative. | |
965 | */ | |
1da177e4 LT |
966 | if (fl->fl_end < request->fl_start - 1) |
967 | goto next_lock; | |
968 | /* If the next lock in the list has entirely bigger | |
969 | * addresses than the new one, insert the lock here. | |
970 | */ | |
449231d6 | 971 | if (fl->fl_start - 1 > request->fl_end) |
1da177e4 LT |
972 | break; |
973 | ||
974 | /* If we come here, the new and old lock are of the | |
975 | * same type and adjacent or overlapping. Make one | |
976 | * lock yielding from the lower start address of both | |
977 | * locks to the higher end address. | |
978 | */ | |
979 | if (fl->fl_start > request->fl_start) | |
980 | fl->fl_start = request->fl_start; | |
981 | else | |
982 | request->fl_start = fl->fl_start; | |
983 | if (fl->fl_end < request->fl_end) | |
984 | fl->fl_end = request->fl_end; | |
985 | else | |
986 | request->fl_end = fl->fl_end; | |
987 | if (added) { | |
988 | locks_delete_lock(before); | |
989 | continue; | |
990 | } | |
991 | request = fl; | |
b9746ef8 | 992 | added = true; |
1da177e4 LT |
993 | } |
994 | else { | |
995 | /* Processing for different lock types is a bit | |
996 | * more complex. | |
997 | */ | |
998 | if (fl->fl_end < request->fl_start) | |
999 | goto next_lock; | |
1000 | if (fl->fl_start > request->fl_end) | |
1001 | break; | |
1002 | if (request->fl_type == F_UNLCK) | |
b9746ef8 | 1003 | added = true; |
1da177e4 LT |
1004 | if (fl->fl_start < request->fl_start) |
1005 | left = fl; | |
1006 | /* If the next lock in the list has a higher end | |
1007 | * address than the new one, insert the new one here. | |
1008 | */ | |
1009 | if (fl->fl_end > request->fl_end) { | |
1010 | right = fl; | |
1011 | break; | |
1012 | } | |
1013 | if (fl->fl_start >= request->fl_start) { | |
1014 | /* The new lock completely replaces an old | |
1015 | * one (This may happen several times). | |
1016 | */ | |
1017 | if (added) { | |
1018 | locks_delete_lock(before); | |
1019 | continue; | |
1020 | } | |
1021 | /* Replace the old lock with the new one. | |
1022 | * Wake up anybody waiting for the old one, | |
1023 | * as the change in lock type might satisfy | |
1024 | * their needs. | |
1025 | */ | |
1026 | locks_wake_up_blocks(fl); | |
1027 | fl->fl_start = request->fl_start; | |
1028 | fl->fl_end = request->fl_end; | |
1029 | fl->fl_type = request->fl_type; | |
47831f35 TM |
1030 | locks_release_private(fl); |
1031 | locks_copy_private(fl, request); | |
1da177e4 | 1032 | request = fl; |
b9746ef8 | 1033 | added = true; |
1da177e4 LT |
1034 | } |
1035 | } | |
1036 | /* Go on to next lock. | |
1037 | */ | |
1038 | next_lock: | |
1039 | before = &fl->fl_next; | |
1040 | } | |
1041 | ||
0d9a490a | 1042 | /* |
1cb36012 JL |
1043 | * The above code only modifies existing locks in case of merging or |
1044 | * replacing. If new lock(s) need to be inserted all modifications are | |
1045 | * done below this, so it's safe yet to bail out. | |
0d9a490a MS |
1046 | */ |
1047 | error = -ENOLCK; /* "no luck" */ | |
1048 | if (right && left == right && !new_fl2) | |
1049 | goto out; | |
1050 | ||
1da177e4 LT |
1051 | error = 0; |
1052 | if (!added) { | |
f475ae95 TM |
1053 | if (request->fl_type == F_UNLCK) { |
1054 | if (request->fl_flags & FL_EXISTS) | |
1055 | error = -ENOENT; | |
1da177e4 | 1056 | goto out; |
f475ae95 | 1057 | } |
0d9a490a MS |
1058 | |
1059 | if (!new_fl) { | |
1060 | error = -ENOLCK; | |
1061 | goto out; | |
1062 | } | |
1da177e4 LT |
1063 | locks_copy_lock(new_fl, request); |
1064 | locks_insert_lock(before, new_fl); | |
1065 | new_fl = NULL; | |
1066 | } | |
1067 | if (right) { | |
1068 | if (left == right) { | |
1069 | /* The new lock breaks the old one in two pieces, | |
1070 | * so we have to use the second new lock. | |
1071 | */ | |
1072 | left = new_fl2; | |
1073 | new_fl2 = NULL; | |
1074 | locks_copy_lock(left, right); | |
1075 | locks_insert_lock(before, left); | |
1076 | } | |
1077 | right->fl_start = request->fl_end + 1; | |
1078 | locks_wake_up_blocks(right); | |
1079 | } | |
1080 | if (left) { | |
1081 | left->fl_end = request->fl_start - 1; | |
1082 | locks_wake_up_blocks(left); | |
1083 | } | |
1084 | out: | |
1c8c601a | 1085 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1086 | /* |
1087 | * Free any unused locks. | |
1088 | */ | |
1089 | if (new_fl) | |
1090 | locks_free_lock(new_fl); | |
1091 | if (new_fl2) | |
1092 | locks_free_lock(new_fl2); | |
1093 | return error; | |
1094 | } | |
1095 | ||
1096 | /** | |
1097 | * posix_lock_file - Apply a POSIX-style lock to a file | |
1098 | * @filp: The file to apply the lock to | |
1099 | * @fl: The lock to be applied | |
150b3934 | 1100 | * @conflock: Place to return a copy of the conflicting lock, if found. |
1da177e4 LT |
1101 | * |
1102 | * Add a POSIX style lock to a file. | |
1103 | * We merge adjacent & overlapping locks whenever possible. | |
1104 | * POSIX locks are sorted by owner task, then by starting address | |
f475ae95 TM |
1105 | * |
1106 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
1107 | * whether or not a lock was successfully freed by testing the return | |
1108 | * value for -ENOENT. | |
1da177e4 | 1109 | */ |
150b3934 | 1110 | int posix_lock_file(struct file *filp, struct file_lock *fl, |
5842add2 AA |
1111 | struct file_lock *conflock) |
1112 | { | |
496ad9aa | 1113 | return __posix_lock_file(file_inode(filp), fl, conflock); |
1da177e4 | 1114 | } |
150b3934 | 1115 | EXPORT_SYMBOL(posix_lock_file); |
1da177e4 LT |
1116 | |
1117 | /** | |
1118 | * posix_lock_file_wait - Apply a POSIX-style lock to a file | |
1119 | * @filp: The file to apply the lock to | |
1120 | * @fl: The lock to be applied | |
1121 | * | |
1122 | * Add a POSIX style lock to a file. | |
1123 | * We merge adjacent & overlapping locks whenever possible. | |
1124 | * POSIX locks are sorted by owner task, then by starting address | |
1125 | */ | |
1126 | int posix_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1127 | { | |
1128 | int error; | |
1129 | might_sleep (); | |
1130 | for (;;) { | |
150b3934 | 1131 | error = posix_lock_file(filp, fl, NULL); |
bde74e4b | 1132 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1133 | break; |
1134 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1135 | if (!error) | |
1136 | continue; | |
1137 | ||
1138 | locks_delete_block(fl); | |
1139 | break; | |
1140 | } | |
1141 | return error; | |
1142 | } | |
1143 | EXPORT_SYMBOL(posix_lock_file_wait); | |
1144 | ||
1145 | /** | |
1146 | * locks_mandatory_locked - Check for an active lock | |
d7a06983 | 1147 | * @file: the file to check |
1da177e4 LT |
1148 | * |
1149 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1150 | * This function is called from locks_verify_locked() only. | |
1151 | */ | |
d7a06983 | 1152 | int locks_mandatory_locked(struct file *file) |
1da177e4 | 1153 | { |
d7a06983 | 1154 | struct inode *inode = file_inode(file); |
1da177e4 LT |
1155 | fl_owner_t owner = current->files; |
1156 | struct file_lock *fl; | |
1157 | ||
1158 | /* | |
1159 | * Search the lock list for this inode for any POSIX locks. | |
1160 | */ | |
1c8c601a | 1161 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1162 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
1163 | if (!IS_POSIX(fl)) | |
1164 | continue; | |
d7a06983 | 1165 | if (fl->fl_owner != owner && fl->fl_owner != (fl_owner_t)file) |
1da177e4 LT |
1166 | break; |
1167 | } | |
1c8c601a | 1168 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1169 | return fl ? -EAGAIN : 0; |
1170 | } | |
1171 | ||
1172 | /** | |
1173 | * locks_mandatory_area - Check for a conflicting lock | |
1174 | * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ | |
1175 | * for shared | |
1176 | * @inode: the file to check | |
1177 | * @filp: how the file was opened (if it was) | |
1178 | * @offset: start of area to check | |
1179 | * @count: length of area to check | |
1180 | * | |
1181 | * Searches the inode's list of locks to find any POSIX locks which conflict. | |
1182 | * This function is called from rw_verify_area() and | |
1183 | * locks_verify_truncate(). | |
1184 | */ | |
1185 | int locks_mandatory_area(int read_write, struct inode *inode, | |
1186 | struct file *filp, loff_t offset, | |
1187 | size_t count) | |
1188 | { | |
1189 | struct file_lock fl; | |
1190 | int error; | |
29723ade | 1191 | bool sleep = false; |
1da177e4 LT |
1192 | |
1193 | locks_init_lock(&fl); | |
1da177e4 LT |
1194 | fl.fl_pid = current->tgid; |
1195 | fl.fl_file = filp; | |
1196 | fl.fl_flags = FL_POSIX | FL_ACCESS; | |
1197 | if (filp && !(filp->f_flags & O_NONBLOCK)) | |
29723ade | 1198 | sleep = true; |
1da177e4 LT |
1199 | fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK; |
1200 | fl.fl_start = offset; | |
1201 | fl.fl_end = offset + count - 1; | |
1202 | ||
1203 | for (;;) { | |
29723ade JL |
1204 | if (filp) { |
1205 | fl.fl_owner = (fl_owner_t)filp; | |
1206 | fl.fl_flags &= ~FL_SLEEP; | |
1207 | error = __posix_lock_file(inode, &fl, NULL); | |
1208 | if (!error) | |
1209 | break; | |
1210 | } | |
1211 | ||
1212 | if (sleep) | |
1213 | fl.fl_flags |= FL_SLEEP; | |
1214 | fl.fl_owner = current->files; | |
150b3934 | 1215 | error = __posix_lock_file(inode, &fl, NULL); |
bde74e4b | 1216 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1217 | break; |
1218 | error = wait_event_interruptible(fl.fl_wait, !fl.fl_next); | |
1219 | if (!error) { | |
1220 | /* | |
1221 | * If we've been sleeping someone might have | |
1222 | * changed the permissions behind our back. | |
1223 | */ | |
a16877ca | 1224 | if (__mandatory_lock(inode)) |
1da177e4 LT |
1225 | continue; |
1226 | } | |
1227 | ||
1228 | locks_delete_block(&fl); | |
1229 | break; | |
1230 | } | |
1231 | ||
1232 | return error; | |
1233 | } | |
1234 | ||
1235 | EXPORT_SYMBOL(locks_mandatory_area); | |
1236 | ||
778fc546 BF |
1237 | static void lease_clear_pending(struct file_lock *fl, int arg) |
1238 | { | |
1239 | switch (arg) { | |
1240 | case F_UNLCK: | |
1241 | fl->fl_flags &= ~FL_UNLOCK_PENDING; | |
1242 | /* fall through: */ | |
1243 | case F_RDLCK: | |
1244 | fl->fl_flags &= ~FL_DOWNGRADE_PENDING; | |
1245 | } | |
1246 | } | |
1247 | ||
1da177e4 LT |
1248 | /* We already had a lease on this file; just change its type */ |
1249 | int lease_modify(struct file_lock **before, int arg) | |
1250 | { | |
1251 | struct file_lock *fl = *before; | |
1252 | int error = assign_type(fl, arg); | |
1253 | ||
1254 | if (error) | |
1255 | return error; | |
778fc546 | 1256 | lease_clear_pending(fl, arg); |
1da177e4 | 1257 | locks_wake_up_blocks(fl); |
3b6e2723 FB |
1258 | if (arg == F_UNLCK) { |
1259 | struct file *filp = fl->fl_file; | |
1260 | ||
1261 | f_delown(filp); | |
1262 | filp->f_owner.signum = 0; | |
96d6d59c BF |
1263 | fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync); |
1264 | if (fl->fl_fasync != NULL) { | |
1265 | printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync); | |
1266 | fl->fl_fasync = NULL; | |
1267 | } | |
1da177e4 | 1268 | locks_delete_lock(before); |
3b6e2723 | 1269 | } |
1da177e4 LT |
1270 | return 0; |
1271 | } | |
1272 | ||
1273 | EXPORT_SYMBOL(lease_modify); | |
1274 | ||
778fc546 BF |
1275 | static bool past_time(unsigned long then) |
1276 | { | |
1277 | if (!then) | |
1278 | /* 0 is a special value meaning "this never expires": */ | |
1279 | return false; | |
1280 | return time_after(jiffies, then); | |
1281 | } | |
1282 | ||
1da177e4 LT |
1283 | static void time_out_leases(struct inode *inode) |
1284 | { | |
1285 | struct file_lock **before; | |
1286 | struct file_lock *fl; | |
1287 | ||
1288 | before = &inode->i_flock; | |
ab83fa4b | 1289 | while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) { |
778fc546 BF |
1290 | if (past_time(fl->fl_downgrade_time)) |
1291 | lease_modify(before, F_RDLCK); | |
1292 | if (past_time(fl->fl_break_time)) | |
1293 | lease_modify(before, F_UNLCK); | |
1da177e4 LT |
1294 | if (fl == *before) /* lease_modify may have freed fl */ |
1295 | before = &fl->fl_next; | |
1296 | } | |
1297 | } | |
1298 | ||
df4e8d2c BF |
1299 | static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker) |
1300 | { | |
1301 | if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) | |
1302 | return false; | |
1303 | return locks_conflict(breaker, lease); | |
1304 | } | |
1305 | ||
1da177e4 LT |
1306 | /** |
1307 | * __break_lease - revoke all outstanding leases on file | |
1308 | * @inode: the inode of the file to return | |
df4e8d2c BF |
1309 | * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR: |
1310 | * break all leases | |
1311 | * @type: FL_LEASE: break leases and delegations; FL_DELEG: break | |
1312 | * only delegations | |
1da177e4 | 1313 | * |
87250dd2 | 1314 | * break_lease (inlined for speed) has checked there already is at least |
1315 | * some kind of lock (maybe a lease) on this file. Leases are broken on | |
1316 | * a call to open() or truncate(). This function can sleep unless you | |
1da177e4 LT |
1317 | * specified %O_NONBLOCK to your open(). |
1318 | */ | |
df4e8d2c | 1319 | int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) |
1da177e4 | 1320 | { |
778fc546 | 1321 | int error = 0; |
1da177e4 LT |
1322 | struct file_lock *new_fl, *flock; |
1323 | struct file_lock *fl; | |
1da177e4 LT |
1324 | unsigned long break_time; |
1325 | int i_have_this_lease = 0; | |
df4e8d2c | 1326 | bool lease_conflict = false; |
8737c930 | 1327 | int want_write = (mode & O_ACCMODE) != O_RDONLY; |
1da177e4 | 1328 | |
8737c930 | 1329 | new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK); |
6d4b9e38 LT |
1330 | if (IS_ERR(new_fl)) |
1331 | return PTR_ERR(new_fl); | |
df4e8d2c | 1332 | new_fl->fl_flags = type; |
1da177e4 | 1333 | |
1c8c601a | 1334 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1335 | |
1336 | time_out_leases(inode); | |
1337 | ||
1338 | flock = inode->i_flock; | |
1339 | if ((flock == NULL) || !IS_LEASE(flock)) | |
1340 | goto out; | |
1341 | ||
df4e8d2c BF |
1342 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { |
1343 | if (leases_conflict(fl, new_fl)) { | |
1344 | lease_conflict = true; | |
1345 | if (fl->fl_owner == current->files) | |
1346 | i_have_this_lease = 1; | |
1347 | } | |
1348 | } | |
1349 | if (!lease_conflict) | |
778fc546 BF |
1350 | goto out; |
1351 | ||
1da177e4 LT |
1352 | break_time = 0; |
1353 | if (lease_break_time > 0) { | |
1354 | break_time = jiffies + lease_break_time * HZ; | |
1355 | if (break_time == 0) | |
1356 | break_time++; /* so that 0 means no break time */ | |
1357 | } | |
1358 | ||
1359 | for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { | |
df4e8d2c BF |
1360 | if (!leases_conflict(fl, new_fl)) |
1361 | continue; | |
778fc546 BF |
1362 | if (want_write) { |
1363 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1364 | continue; | |
1365 | fl->fl_flags |= FL_UNLOCK_PENDING; | |
1da177e4 | 1366 | fl->fl_break_time = break_time; |
778fc546 BF |
1367 | } else { |
1368 | if (lease_breaking(flock)) | |
1369 | continue; | |
1370 | fl->fl_flags |= FL_DOWNGRADE_PENDING; | |
1371 | fl->fl_downgrade_time = break_time; | |
1da177e4 | 1372 | } |
778fc546 | 1373 | fl->fl_lmops->lm_break(fl); |
1da177e4 LT |
1374 | } |
1375 | ||
1376 | if (i_have_this_lease || (mode & O_NONBLOCK)) { | |
1377 | error = -EWOULDBLOCK; | |
1378 | goto out; | |
1379 | } | |
1380 | ||
1381 | restart: | |
1382 | break_time = flock->fl_break_time; | |
f1c6bb2c | 1383 | if (break_time != 0) |
1da177e4 | 1384 | break_time -= jiffies; |
f1c6bb2c JL |
1385 | if (break_time == 0) |
1386 | break_time++; | |
4321e01e | 1387 | locks_insert_block(flock, new_fl); |
1c8c601a | 1388 | spin_unlock(&inode->i_lock); |
4321e01e MW |
1389 | error = wait_event_interruptible_timeout(new_fl->fl_wait, |
1390 | !new_fl->fl_next, break_time); | |
1c8c601a JL |
1391 | spin_lock(&inode->i_lock); |
1392 | locks_delete_block(new_fl); | |
1da177e4 LT |
1393 | if (error >= 0) { |
1394 | if (error == 0) | |
1395 | time_out_leases(inode); | |
778fc546 BF |
1396 | /* |
1397 | * Wait for the next conflicting lease that has not been | |
1398 | * broken yet | |
1399 | */ | |
1da177e4 LT |
1400 | for (flock = inode->i_flock; flock && IS_LEASE(flock); |
1401 | flock = flock->fl_next) { | |
df4e8d2c | 1402 | if (leases_conflict(new_fl, flock)) |
1da177e4 LT |
1403 | goto restart; |
1404 | } | |
1405 | error = 0; | |
1406 | } | |
1407 | ||
1408 | out: | |
1c8c601a | 1409 | spin_unlock(&inode->i_lock); |
6d4b9e38 | 1410 | locks_free_lock(new_fl); |
1da177e4 LT |
1411 | return error; |
1412 | } | |
1413 | ||
1414 | EXPORT_SYMBOL(__break_lease); | |
1415 | ||
1416 | /** | |
a6b91919 | 1417 | * lease_get_mtime - get the last modified time of an inode |
1da177e4 LT |
1418 | * @inode: the inode |
1419 | * @time: pointer to a timespec which will contain the last modified time | |
1420 | * | |
1421 | * This is to force NFS clients to flush their caches for files with | |
1422 | * exclusive leases. The justification is that if someone has an | |
a6b91919 | 1423 | * exclusive lease, then they could be modifying it. |
1da177e4 LT |
1424 | */ |
1425 | void lease_get_mtime(struct inode *inode, struct timespec *time) | |
1426 | { | |
1427 | struct file_lock *flock = inode->i_flock; | |
0ee5c6d6 | 1428 | if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK)) |
1da177e4 LT |
1429 | *time = current_fs_time(inode->i_sb); |
1430 | else | |
1431 | *time = inode->i_mtime; | |
1432 | } | |
1433 | ||
1434 | EXPORT_SYMBOL(lease_get_mtime); | |
1435 | ||
1436 | /** | |
1437 | * fcntl_getlease - Enquire what lease is currently active | |
1438 | * @filp: the file | |
1439 | * | |
1440 | * The value returned by this function will be one of | |
1441 | * (if no lease break is pending): | |
1442 | * | |
1443 | * %F_RDLCK to indicate a shared lease is held. | |
1444 | * | |
1445 | * %F_WRLCK to indicate an exclusive lease is held. | |
1446 | * | |
1447 | * %F_UNLCK to indicate no lease is held. | |
1448 | * | |
1449 | * (if a lease break is pending): | |
1450 | * | |
1451 | * %F_RDLCK to indicate an exclusive lease needs to be | |
1452 | * changed to a shared lease (or removed). | |
1453 | * | |
1454 | * %F_UNLCK to indicate the lease needs to be removed. | |
1455 | * | |
1456 | * XXX: sfr & willy disagree over whether F_INPROGRESS | |
1457 | * should be returned to userspace. | |
1458 | */ | |
1459 | int fcntl_getlease(struct file *filp) | |
1460 | { | |
1461 | struct file_lock *fl; | |
1c8c601a | 1462 | struct inode *inode = file_inode(filp); |
1da177e4 LT |
1463 | int type = F_UNLCK; |
1464 | ||
1c8c601a | 1465 | spin_lock(&inode->i_lock); |
496ad9aa AV |
1466 | time_out_leases(file_inode(filp)); |
1467 | for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl); | |
1da177e4 LT |
1468 | fl = fl->fl_next) { |
1469 | if (fl->fl_file == filp) { | |
778fc546 | 1470 | type = target_leasetype(fl); |
1da177e4 LT |
1471 | break; |
1472 | } | |
1473 | } | |
1c8c601a | 1474 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1475 | return type; |
1476 | } | |
1477 | ||
24cbe784 JL |
1478 | /** |
1479 | * check_conflicting_open - see if the given dentry points to a file that has | |
1480 | * an existing open that would conflict with the | |
1481 | * desired lease. | |
1482 | * @dentry: dentry to check | |
1483 | * @arg: type of lease that we're trying to acquire | |
1484 | * | |
1485 | * Check to see if there's an existing open fd on this file that would | |
1486 | * conflict with the lease we're trying to set. | |
1487 | */ | |
1488 | static int | |
1489 | check_conflicting_open(const struct dentry *dentry, const long arg) | |
1490 | { | |
1491 | int ret = 0; | |
1492 | struct inode *inode = dentry->d_inode; | |
1493 | ||
1494 | if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) | |
1495 | return -EAGAIN; | |
1496 | ||
1497 | if ((arg == F_WRLCK) && ((d_count(dentry) > 1) || | |
1498 | (atomic_read(&inode->i_count) > 1))) | |
1499 | ret = -EAGAIN; | |
1500 | ||
1501 | return ret; | |
1502 | } | |
1503 | ||
d4f22d19 | 1504 | static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp) |
1da177e4 | 1505 | { |
7eaae282 | 1506 | struct file_lock *fl, **before, **my_before = NULL, *lease; |
0f7fc9e4 | 1507 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 1508 | struct inode *inode = dentry->d_inode; |
df4e8d2c | 1509 | bool is_deleg = (*flp)->fl_flags & FL_DELEG; |
c1f24ef4 | 1510 | int error; |
1da177e4 | 1511 | |
096657b6 | 1512 | lease = *flp; |
df4e8d2c BF |
1513 | /* |
1514 | * In the delegation case we need mutual exclusion with | |
1515 | * a number of operations that take the i_mutex. We trylock | |
1516 | * because delegations are an optional optimization, and if | |
1517 | * there's some chance of a conflict--we'd rather not | |
1518 | * bother, maybe that's a sign this just isn't a good file to | |
1519 | * hand out a delegation on. | |
1520 | */ | |
1521 | if (is_deleg && !mutex_trylock(&inode->i_mutex)) | |
1522 | return -EAGAIN; | |
1523 | ||
1524 | if (is_deleg && arg == F_WRLCK) { | |
1525 | /* Write delegations are not currently supported: */ | |
4fdb793f | 1526 | mutex_unlock(&inode->i_mutex); |
df4e8d2c BF |
1527 | WARN_ON_ONCE(1); |
1528 | return -EINVAL; | |
1529 | } | |
096657b6 | 1530 | |
24cbe784 JL |
1531 | error = check_conflicting_open(dentry, arg); |
1532 | if (error) | |
096657b6 | 1533 | goto out; |
6d5e8b05 | 1534 | |
1da177e4 LT |
1535 | /* |
1536 | * At this point, we know that if there is an exclusive | |
1537 | * lease on this file, then we hold it on this filp | |
1538 | * (otherwise our open of this file would have blocked). | |
1539 | * And if we are trying to acquire an exclusive lease, | |
1540 | * then the file is not open by anyone (including us) | |
1541 | * except for this filp. | |
1542 | */ | |
c1f24ef4 | 1543 | error = -EAGAIN; |
1da177e4 LT |
1544 | for (before = &inode->i_flock; |
1545 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1546 | before = &fl->fl_next) { | |
c1f24ef4 | 1547 | if (fl->fl_file == filp) { |
1da177e4 | 1548 | my_before = before; |
c1f24ef4 BF |
1549 | continue; |
1550 | } | |
1551 | /* | |
1552 | * No exclusive leases if someone else has a lease on | |
1553 | * this file: | |
1554 | */ | |
1555 | if (arg == F_WRLCK) | |
1556 | goto out; | |
1557 | /* | |
1558 | * Modifying our existing lease is OK, but no getting a | |
1559 | * new lease if someone else is opening for write: | |
1560 | */ | |
1561 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1562 | goto out; | |
1da177e4 LT |
1563 | } |
1564 | ||
1da177e4 | 1565 | if (my_before != NULL) { |
8fb47a4f | 1566 | error = lease->fl_lmops->lm_change(my_before, arg); |
51ee4b84 CH |
1567 | if (!error) |
1568 | *flp = *my_before; | |
1da177e4 LT |
1569 | goto out; |
1570 | } | |
1571 | ||
1da177e4 LT |
1572 | error = -EINVAL; |
1573 | if (!leases_enable) | |
1574 | goto out; | |
1575 | ||
c5b1f0d9 | 1576 | locks_insert_lock(before, lease); |
24cbe784 JL |
1577 | /* |
1578 | * The check in break_lease() is lockless. It's possible for another | |
1579 | * open to race in after we did the earlier check for a conflicting | |
1580 | * open but before the lease was inserted. Check again for a | |
1581 | * conflicting open and cancel the lease if there is one. | |
1582 | * | |
1583 | * We also add a barrier here to ensure that the insertion of the lock | |
1584 | * precedes these checks. | |
1585 | */ | |
1586 | smp_mb(); | |
1587 | error = check_conflicting_open(dentry, arg); | |
1588 | if (error) | |
1589 | locks_unlink_lock(flp); | |
1da177e4 | 1590 | out: |
df4e8d2c BF |
1591 | if (is_deleg) |
1592 | mutex_unlock(&inode->i_mutex); | |
1da177e4 LT |
1593 | return error; |
1594 | } | |
8335ebd9 | 1595 | |
d4f22d19 | 1596 | static int generic_delete_lease(struct file *filp, struct file_lock **flp) |
8335ebd9 BF |
1597 | { |
1598 | struct file_lock *fl, **before; | |
1599 | struct dentry *dentry = filp->f_path.dentry; | |
1600 | struct inode *inode = dentry->d_inode; | |
1601 | ||
1602 | for (before = &inode->i_flock; | |
1603 | ((fl = *before) != NULL) && IS_LEASE(fl); | |
1604 | before = &fl->fl_next) { | |
1605 | if (fl->fl_file != filp) | |
1606 | continue; | |
1607 | return (*flp)->fl_lmops->lm_change(before, F_UNLCK); | |
1608 | } | |
1609 | return -EAGAIN; | |
1610 | } | |
1611 | ||
1612 | /** | |
1613 | * generic_setlease - sets a lease on an open file | |
1614 | * @filp: file pointer | |
1615 | * @arg: type of lease to obtain | |
1616 | * @flp: input - file_lock to use, output - file_lock inserted | |
1617 | * | |
1618 | * The (input) flp->fl_lmops->lm_break function is required | |
1619 | * by break_lease(). | |
1620 | * | |
1c8c601a | 1621 | * Called with inode->i_lock held. |
8335ebd9 BF |
1622 | */ |
1623 | int generic_setlease(struct file *filp, long arg, struct file_lock **flp) | |
1624 | { | |
1625 | struct dentry *dentry = filp->f_path.dentry; | |
1626 | struct inode *inode = dentry->d_inode; | |
1627 | int error; | |
1628 | ||
8e96e3b7 | 1629 | if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE)) |
8335ebd9 BF |
1630 | return -EACCES; |
1631 | if (!S_ISREG(inode->i_mode)) | |
1632 | return -EINVAL; | |
1633 | error = security_file_lock(filp, arg); | |
1634 | if (error) | |
1635 | return error; | |
1636 | ||
1637 | time_out_leases(inode); | |
1638 | ||
1639 | BUG_ON(!(*flp)->fl_lmops->lm_break); | |
1640 | ||
1641 | switch (arg) { | |
1642 | case F_UNLCK: | |
1643 | return generic_delete_lease(filp, flp); | |
1644 | case F_RDLCK: | |
1645 | case F_WRLCK: | |
1646 | return generic_add_lease(filp, arg, flp); | |
1647 | default: | |
8d657eb3 | 1648 | return -EINVAL; |
8335ebd9 BF |
1649 | } |
1650 | } | |
0af1a450 | 1651 | EXPORT_SYMBOL(generic_setlease); |
1da177e4 | 1652 | |
b89f4321 AB |
1653 | static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1654 | { | |
72c2d531 | 1655 | if (filp->f_op->setlease) |
b89f4321 AB |
1656 | return filp->f_op->setlease(filp, arg, lease); |
1657 | else | |
1658 | return generic_setlease(filp, arg, lease); | |
1659 | } | |
1660 | ||
1661 | /** | |
a9933cea | 1662 | * vfs_setlease - sets a lease on an open file |
1da177e4 LT |
1663 | * @filp: file pointer |
1664 | * @arg: type of lease to obtain | |
1665 | * @lease: file_lock to use | |
1666 | * | |
1667 | * Call this to establish a lease on the file. | |
8fb47a4f | 1668 | * The (*lease)->fl_lmops->lm_break operation must be set; if not, |
f9ffed26 BF |
1669 | * break_lease will oops! |
1670 | * | |
1671 | * This will call the filesystem's setlease file method, if | |
1672 | * defined. Note that there is no getlease method; instead, the | |
1673 | * filesystem setlease method should call back to setlease() to | |
1674 | * add a lease to the inode's lease list, where fcntl_getlease() can | |
1675 | * find it. Since fcntl_getlease() only reports whether the current | |
1676 | * task holds a lease, a cluster filesystem need only do this for | |
1677 | * leases held by processes on this node. | |
1678 | * | |
1679 | * There is also no break_lease method; filesystems that | |
c9404c9c | 1680 | * handle their own leases should break leases themselves from the |
f9ffed26 BF |
1681 | * filesystem's open, create, and (on truncate) setattr methods. |
1682 | * | |
1683 | * Warning: the only current setlease methods exist only to disable | |
1684 | * leases in certain cases. More vfs changes may be required to | |
1685 | * allow a full filesystem lease implementation. | |
1da177e4 LT |
1686 | */ |
1687 | ||
a9933cea | 1688 | int vfs_setlease(struct file *filp, long arg, struct file_lock **lease) |
1da177e4 | 1689 | { |
1c8c601a | 1690 | struct inode *inode = file_inode(filp); |
1da177e4 LT |
1691 | int error; |
1692 | ||
1c8c601a | 1693 | spin_lock(&inode->i_lock); |
b89f4321 | 1694 | error = __vfs_setlease(filp, arg, lease); |
1c8c601a | 1695 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1696 | |
1697 | return error; | |
1698 | } | |
a9933cea | 1699 | EXPORT_SYMBOL_GPL(vfs_setlease); |
1da177e4 | 1700 | |
0ceaf6c7 BF |
1701 | static int do_fcntl_delete_lease(struct file *filp) |
1702 | { | |
1703 | struct file_lock fl, *flp = &fl; | |
1704 | ||
1705 | lease_init(filp, F_UNLCK, flp); | |
1706 | ||
1707 | return vfs_setlease(filp, F_UNLCK, &flp); | |
1708 | } | |
1709 | ||
1710 | static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg) | |
1da177e4 | 1711 | { |
3df057ac | 1712 | struct file_lock *fl, *ret; |
1c8c601a | 1713 | struct inode *inode = file_inode(filp); |
f7347ce4 | 1714 | struct fasync_struct *new; |
1da177e4 LT |
1715 | int error; |
1716 | ||
c5b1f0d9 AB |
1717 | fl = lease_alloc(filp, arg); |
1718 | if (IS_ERR(fl)) | |
1719 | return PTR_ERR(fl); | |
1da177e4 | 1720 | |
f7347ce4 LT |
1721 | new = fasync_alloc(); |
1722 | if (!new) { | |
1723 | locks_free_lock(fl); | |
1724 | return -ENOMEM; | |
1725 | } | |
3df057ac | 1726 | ret = fl; |
1c8c601a | 1727 | spin_lock(&inode->i_lock); |
8896b93f | 1728 | error = __vfs_setlease(filp, arg, &ret); |
51ee4b84 | 1729 | if (error) { |
1c8c601a | 1730 | spin_unlock(&inode->i_lock); |
51ee4b84 CH |
1731 | locks_free_lock(fl); |
1732 | goto out_free_fasync; | |
1733 | } | |
3df057ac BF |
1734 | if (ret != fl) |
1735 | locks_free_lock(fl); | |
1da177e4 | 1736 | |
f7347ce4 LT |
1737 | /* |
1738 | * fasync_insert_entry() returns the old entry if any. | |
1739 | * If there was no old entry, then it used 'new' and | |
1740 | * inserted it into the fasync list. Clear new so that | |
1741 | * we don't release it here. | |
1742 | */ | |
3df057ac | 1743 | if (!fasync_insert_entry(fd, filp, &ret->fl_fasync, new)) |
f7347ce4 LT |
1744 | new = NULL; |
1745 | ||
8896b93f | 1746 | error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); |
1c8c601a | 1747 | spin_unlock(&inode->i_lock); |
51ee4b84 CH |
1748 | |
1749 | out_free_fasync: | |
f7347ce4 LT |
1750 | if (new) |
1751 | fasync_free(new); | |
1da177e4 LT |
1752 | return error; |
1753 | } | |
1754 | ||
0ceaf6c7 BF |
1755 | /** |
1756 | * fcntl_setlease - sets a lease on an open file | |
1757 | * @fd: open file descriptor | |
1758 | * @filp: file pointer | |
1759 | * @arg: type of lease to obtain | |
1760 | * | |
1761 | * Call this fcntl to establish a lease on the file. | |
1762 | * Note that you also need to call %F_SETSIG to | |
1763 | * receive a signal when the lease is broken. | |
1764 | */ | |
1765 | int fcntl_setlease(unsigned int fd, struct file *filp, long arg) | |
1766 | { | |
1767 | if (arg == F_UNLCK) | |
1768 | return do_fcntl_delete_lease(filp); | |
1769 | return do_fcntl_add_lease(fd, filp, arg); | |
1770 | } | |
1771 | ||
1da177e4 LT |
1772 | /** |
1773 | * flock_lock_file_wait - Apply a FLOCK-style lock to a file | |
1774 | * @filp: The file to apply the lock to | |
1775 | * @fl: The lock to be applied | |
1776 | * | |
1777 | * Add a FLOCK style lock to a file. | |
1778 | */ | |
1779 | int flock_lock_file_wait(struct file *filp, struct file_lock *fl) | |
1780 | { | |
1781 | int error; | |
1782 | might_sleep(); | |
1783 | for (;;) { | |
1784 | error = flock_lock_file(filp, fl); | |
bde74e4b | 1785 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 LT |
1786 | break; |
1787 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); | |
1788 | if (!error) | |
1789 | continue; | |
1790 | ||
1791 | locks_delete_block(fl); | |
1792 | break; | |
1793 | } | |
1794 | return error; | |
1795 | } | |
1796 | ||
1797 | EXPORT_SYMBOL(flock_lock_file_wait); | |
1798 | ||
1799 | /** | |
1800 | * sys_flock: - flock() system call. | |
1801 | * @fd: the file descriptor to lock. | |
1802 | * @cmd: the type of lock to apply. | |
1803 | * | |
1804 | * Apply a %FL_FLOCK style lock to an open file descriptor. | |
1805 | * The @cmd can be one of | |
1806 | * | |
1807 | * %LOCK_SH -- a shared lock. | |
1808 | * | |
1809 | * %LOCK_EX -- an exclusive lock. | |
1810 | * | |
1811 | * %LOCK_UN -- remove an existing lock. | |
1812 | * | |
1813 | * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes. | |
1814 | * | |
1815 | * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other | |
1816 | * processes read and write access respectively. | |
1817 | */ | |
002c8976 | 1818 | SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) |
1da177e4 | 1819 | { |
2903ff01 | 1820 | struct fd f = fdget(fd); |
1da177e4 LT |
1821 | struct file_lock *lock; |
1822 | int can_sleep, unlock; | |
1823 | int error; | |
1824 | ||
1825 | error = -EBADF; | |
2903ff01 | 1826 | if (!f.file) |
1da177e4 LT |
1827 | goto out; |
1828 | ||
1829 | can_sleep = !(cmd & LOCK_NB); | |
1830 | cmd &= ~LOCK_NB; | |
1831 | unlock = (cmd == LOCK_UN); | |
1832 | ||
aeb5d727 | 1833 | if (!unlock && !(cmd & LOCK_MAND) && |
2903ff01 | 1834 | !(f.file->f_mode & (FMODE_READ|FMODE_WRITE))) |
1da177e4 LT |
1835 | goto out_putf; |
1836 | ||
2903ff01 | 1837 | error = flock_make_lock(f.file, &lock, cmd); |
1da177e4 LT |
1838 | if (error) |
1839 | goto out_putf; | |
1840 | if (can_sleep) | |
1841 | lock->fl_flags |= FL_SLEEP; | |
1842 | ||
2903ff01 | 1843 | error = security_file_lock(f.file, lock->fl_type); |
1da177e4 LT |
1844 | if (error) |
1845 | goto out_free; | |
1846 | ||
72c2d531 | 1847 | if (f.file->f_op->flock) |
2903ff01 | 1848 | error = f.file->f_op->flock(f.file, |
1da177e4 LT |
1849 | (can_sleep) ? F_SETLKW : F_SETLK, |
1850 | lock); | |
1851 | else | |
2903ff01 | 1852 | error = flock_lock_file_wait(f.file, lock); |
1da177e4 LT |
1853 | |
1854 | out_free: | |
993dfa87 | 1855 | locks_free_lock(lock); |
1da177e4 LT |
1856 | |
1857 | out_putf: | |
2903ff01 | 1858 | fdput(f); |
1da177e4 LT |
1859 | out: |
1860 | return error; | |
1861 | } | |
1862 | ||
3ee17abd BF |
1863 | /** |
1864 | * vfs_test_lock - test file byte range lock | |
1865 | * @filp: The file to test lock for | |
6924c554 | 1866 | * @fl: The lock to test; also used to hold result |
3ee17abd BF |
1867 | * |
1868 | * Returns -ERRNO on failure. Indicates presence of conflicting lock by | |
1869 | * setting conf->fl_type to something other than F_UNLCK. | |
1870 | */ | |
1871 | int vfs_test_lock(struct file *filp, struct file_lock *fl) | |
1872 | { | |
72c2d531 | 1873 | if (filp->f_op->lock) |
3ee17abd BF |
1874 | return filp->f_op->lock(filp, F_GETLK, fl); |
1875 | posix_test_lock(filp, fl); | |
1876 | return 0; | |
1877 | } | |
1878 | EXPORT_SYMBOL_GPL(vfs_test_lock); | |
1879 | ||
c2fa1b8a BF |
1880 | static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) |
1881 | { | |
cff2fce5 | 1882 | flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid; |
c2fa1b8a BF |
1883 | #if BITS_PER_LONG == 32 |
1884 | /* | |
1885 | * Make sure we can represent the posix lock via | |
1886 | * legacy 32bit flock. | |
1887 | */ | |
1888 | if (fl->fl_start > OFFT_OFFSET_MAX) | |
1889 | return -EOVERFLOW; | |
1890 | if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX) | |
1891 | return -EOVERFLOW; | |
1892 | #endif | |
1893 | flock->l_start = fl->fl_start; | |
1894 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1895 | fl->fl_end - fl->fl_start + 1; | |
1896 | flock->l_whence = 0; | |
129a84de | 1897 | flock->l_type = fl->fl_type; |
c2fa1b8a BF |
1898 | return 0; |
1899 | } | |
1900 | ||
1901 | #if BITS_PER_LONG == 32 | |
1902 | static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) | |
1903 | { | |
cff2fce5 | 1904 | flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid; |
c2fa1b8a BF |
1905 | flock->l_start = fl->fl_start; |
1906 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
1907 | fl->fl_end - fl->fl_start + 1; | |
1908 | flock->l_whence = 0; | |
1909 | flock->l_type = fl->fl_type; | |
1910 | } | |
1911 | #endif | |
1912 | ||
1da177e4 LT |
1913 | /* Report the first existing lock that would conflict with l. |
1914 | * This implements the F_GETLK command of fcntl(). | |
1915 | */ | |
c1e62b8f | 1916 | int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l) |
1da177e4 | 1917 | { |
9d6a8c5c | 1918 | struct file_lock file_lock; |
1da177e4 LT |
1919 | struct flock flock; |
1920 | int error; | |
1921 | ||
1922 | error = -EFAULT; | |
1923 | if (copy_from_user(&flock, l, sizeof(flock))) | |
1924 | goto out; | |
1925 | error = -EINVAL; | |
1926 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
1927 | goto out; | |
1928 | ||
1929 | error = flock_to_posix_lock(filp, &file_lock, &flock); | |
1930 | if (error) | |
1931 | goto out; | |
1932 | ||
0d3f7a2d | 1933 | if (cmd == F_OFD_GETLK) { |
90478939 JL |
1934 | error = -EINVAL; |
1935 | if (flock.l_pid != 0) | |
1936 | goto out; | |
1937 | ||
5d50ffd7 | 1938 | cmd = F_GETLK; |
cff2fce5 | 1939 | file_lock.fl_flags |= FL_OFDLCK; |
5d50ffd7 JL |
1940 | file_lock.fl_owner = (fl_owner_t)filp; |
1941 | } | |
1942 | ||
3ee17abd BF |
1943 | error = vfs_test_lock(filp, &file_lock); |
1944 | if (error) | |
1945 | goto out; | |
1da177e4 | 1946 | |
9d6a8c5c ME |
1947 | flock.l_type = file_lock.fl_type; |
1948 | if (file_lock.fl_type != F_UNLCK) { | |
1949 | error = posix_lock_to_flock(&flock, &file_lock); | |
c2fa1b8a | 1950 | if (error) |
1da177e4 | 1951 | goto out; |
1da177e4 LT |
1952 | } |
1953 | error = -EFAULT; | |
1954 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
1955 | error = 0; | |
1956 | out: | |
1957 | return error; | |
1958 | } | |
1959 | ||
7723ec97 ME |
1960 | /** |
1961 | * vfs_lock_file - file byte range lock | |
1962 | * @filp: The file to apply the lock to | |
1963 | * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.) | |
1964 | * @fl: The lock to be applied | |
150b3934 ME |
1965 | * @conf: Place to return a copy of the conflicting lock, if found. |
1966 | * | |
1967 | * A caller that doesn't care about the conflicting lock may pass NULL | |
1968 | * as the final argument. | |
1969 | * | |
1970 | * If the filesystem defines a private ->lock() method, then @conf will | |
1971 | * be left unchanged; so a caller that cares should initialize it to | |
1972 | * some acceptable default. | |
2beb6614 ME |
1973 | * |
1974 | * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX | |
1975 | * locks, the ->lock() interface may return asynchronously, before the lock has | |
1976 | * been granted or denied by the underlying filesystem, if (and only if) | |
8fb47a4f | 1977 | * lm_grant is set. Callers expecting ->lock() to return asynchronously |
2beb6614 ME |
1978 | * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if) |
1979 | * the request is for a blocking lock. When ->lock() does return asynchronously, | |
8fb47a4f | 1980 | * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock |
2beb6614 ME |
1981 | * request completes. |
1982 | * If the request is for non-blocking lock the file system should return | |
bde74e4b MS |
1983 | * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine |
1984 | * with the result. If the request timed out the callback routine will return a | |
2beb6614 ME |
1985 | * nonzero return code and the file system should release the lock. The file |
1986 | * system is also responsible to keep a corresponding posix lock when it | |
1987 | * grants a lock so the VFS can find out which locks are locally held and do | |
1988 | * the correct lock cleanup when required. | |
1989 | * The underlying filesystem must not drop the kernel lock or call | |
8fb47a4f | 1990 | * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED |
2beb6614 | 1991 | * return code. |
7723ec97 | 1992 | */ |
150b3934 | 1993 | int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf) |
7723ec97 | 1994 | { |
72c2d531 | 1995 | if (filp->f_op->lock) |
7723ec97 ME |
1996 | return filp->f_op->lock(filp, cmd, fl); |
1997 | else | |
150b3934 | 1998 | return posix_lock_file(filp, fl, conf); |
7723ec97 ME |
1999 | } |
2000 | EXPORT_SYMBOL_GPL(vfs_lock_file); | |
2001 | ||
b648a6de MS |
2002 | static int do_lock_file_wait(struct file *filp, unsigned int cmd, |
2003 | struct file_lock *fl) | |
2004 | { | |
2005 | int error; | |
2006 | ||
2007 | error = security_file_lock(filp, fl->fl_type); | |
2008 | if (error) | |
2009 | return error; | |
2010 | ||
764c76b3 MS |
2011 | for (;;) { |
2012 | error = vfs_lock_file(filp, cmd, fl, NULL); | |
2013 | if (error != FILE_LOCK_DEFERRED) | |
b648a6de | 2014 | break; |
764c76b3 MS |
2015 | error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); |
2016 | if (!error) | |
2017 | continue; | |
2018 | ||
2019 | locks_delete_block(fl); | |
2020 | break; | |
b648a6de MS |
2021 | } |
2022 | ||
2023 | return error; | |
2024 | } | |
2025 | ||
cf01f4ee JL |
2026 | /* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */ |
2027 | static int | |
2028 | check_fmode_for_setlk(struct file_lock *fl) | |
2029 | { | |
2030 | switch (fl->fl_type) { | |
2031 | case F_RDLCK: | |
2032 | if (!(fl->fl_file->f_mode & FMODE_READ)) | |
2033 | return -EBADF; | |
2034 | break; | |
2035 | case F_WRLCK: | |
2036 | if (!(fl->fl_file->f_mode & FMODE_WRITE)) | |
2037 | return -EBADF; | |
2038 | } | |
2039 | return 0; | |
2040 | } | |
2041 | ||
1da177e4 LT |
2042 | /* Apply the lock described by l to an open file descriptor. |
2043 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2044 | */ | |
c293621b PS |
2045 | int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, |
2046 | struct flock __user *l) | |
1da177e4 LT |
2047 | { |
2048 | struct file_lock *file_lock = locks_alloc_lock(); | |
2049 | struct flock flock; | |
2050 | struct inode *inode; | |
0b2bac2f | 2051 | struct file *f; |
1da177e4 LT |
2052 | int error; |
2053 | ||
2054 | if (file_lock == NULL) | |
2055 | return -ENOLCK; | |
2056 | ||
2057 | /* | |
2058 | * This might block, so we do it before checking the inode. | |
2059 | */ | |
2060 | error = -EFAULT; | |
2061 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2062 | goto out; | |
2063 | ||
496ad9aa | 2064 | inode = file_inode(filp); |
1da177e4 LT |
2065 | |
2066 | /* Don't allow mandatory locks on files that may be memory mapped | |
2067 | * and shared. | |
2068 | */ | |
a16877ca | 2069 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
2070 | error = -EAGAIN; |
2071 | goto out; | |
2072 | } | |
2073 | ||
c293621b | 2074 | again: |
1da177e4 LT |
2075 | error = flock_to_posix_lock(filp, file_lock, &flock); |
2076 | if (error) | |
2077 | goto out; | |
5d50ffd7 | 2078 | |
cf01f4ee JL |
2079 | error = check_fmode_for_setlk(file_lock); |
2080 | if (error) | |
2081 | goto out; | |
2082 | ||
5d50ffd7 JL |
2083 | /* |
2084 | * If the cmd is requesting file-private locks, then set the | |
cff2fce5 | 2085 | * FL_OFDLCK flag and override the owner. |
5d50ffd7 JL |
2086 | */ |
2087 | switch (cmd) { | |
0d3f7a2d | 2088 | case F_OFD_SETLK: |
90478939 JL |
2089 | error = -EINVAL; |
2090 | if (flock.l_pid != 0) | |
2091 | goto out; | |
2092 | ||
5d50ffd7 | 2093 | cmd = F_SETLK; |
cff2fce5 | 2094 | file_lock->fl_flags |= FL_OFDLCK; |
5d50ffd7 JL |
2095 | file_lock->fl_owner = (fl_owner_t)filp; |
2096 | break; | |
0d3f7a2d | 2097 | case F_OFD_SETLKW: |
90478939 JL |
2098 | error = -EINVAL; |
2099 | if (flock.l_pid != 0) | |
2100 | goto out; | |
2101 | ||
5d50ffd7 | 2102 | cmd = F_SETLKW; |
cff2fce5 | 2103 | file_lock->fl_flags |= FL_OFDLCK; |
5d50ffd7 JL |
2104 | file_lock->fl_owner = (fl_owner_t)filp; |
2105 | /* Fallthrough */ | |
2106 | case F_SETLKW: | |
1da177e4 LT |
2107 | file_lock->fl_flags |= FL_SLEEP; |
2108 | } | |
5d50ffd7 | 2109 | |
b648a6de | 2110 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2111 | |
c293621b PS |
2112 | /* |
2113 | * Attempt to detect a close/fcntl race and recover by | |
2114 | * releasing the lock that was just acquired. | |
2115 | */ | |
0b2bac2f AV |
2116 | /* |
2117 | * we need that spin_lock here - it prevents reordering between | |
2118 | * update of inode->i_flock and check for it done in close(). | |
2119 | * rcu_read_lock() wouldn't do. | |
2120 | */ | |
2121 | spin_lock(¤t->files->file_lock); | |
2122 | f = fcheck(fd); | |
2123 | spin_unlock(¤t->files->file_lock); | |
2124 | if (!error && f != filp && flock.l_type != F_UNLCK) { | |
c293621b PS |
2125 | flock.l_type = F_UNLCK; |
2126 | goto again; | |
1da177e4 LT |
2127 | } |
2128 | ||
c293621b | 2129 | out: |
1da177e4 LT |
2130 | locks_free_lock(file_lock); |
2131 | return error; | |
2132 | } | |
2133 | ||
2134 | #if BITS_PER_LONG == 32 | |
2135 | /* Report the first existing lock that would conflict with l. | |
2136 | * This implements the F_GETLK command of fcntl(). | |
2137 | */ | |
c1e62b8f | 2138 | int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) |
1da177e4 | 2139 | { |
9d6a8c5c | 2140 | struct file_lock file_lock; |
1da177e4 LT |
2141 | struct flock64 flock; |
2142 | int error; | |
2143 | ||
2144 | error = -EFAULT; | |
2145 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2146 | goto out; | |
2147 | error = -EINVAL; | |
2148 | if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK)) | |
2149 | goto out; | |
2150 | ||
2151 | error = flock64_to_posix_lock(filp, &file_lock, &flock); | |
2152 | if (error) | |
2153 | goto out; | |
2154 | ||
0d3f7a2d | 2155 | if (cmd == F_OFD_GETLK) { |
90478939 JL |
2156 | error = -EINVAL; |
2157 | if (flock.l_pid != 0) | |
2158 | goto out; | |
2159 | ||
5d50ffd7 | 2160 | cmd = F_GETLK64; |
cff2fce5 | 2161 | file_lock.fl_flags |= FL_OFDLCK; |
5d50ffd7 JL |
2162 | file_lock.fl_owner = (fl_owner_t)filp; |
2163 | } | |
2164 | ||
3ee17abd BF |
2165 | error = vfs_test_lock(filp, &file_lock); |
2166 | if (error) | |
2167 | goto out; | |
2168 | ||
9d6a8c5c ME |
2169 | flock.l_type = file_lock.fl_type; |
2170 | if (file_lock.fl_type != F_UNLCK) | |
2171 | posix_lock_to_flock64(&flock, &file_lock); | |
2172 | ||
1da177e4 LT |
2173 | error = -EFAULT; |
2174 | if (!copy_to_user(l, &flock, sizeof(flock))) | |
2175 | error = 0; | |
2176 | ||
2177 | out: | |
2178 | return error; | |
2179 | } | |
2180 | ||
2181 | /* Apply the lock described by l to an open file descriptor. | |
2182 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2183 | */ | |
c293621b PS |
2184 | int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, |
2185 | struct flock64 __user *l) | |
1da177e4 LT |
2186 | { |
2187 | struct file_lock *file_lock = locks_alloc_lock(); | |
2188 | struct flock64 flock; | |
2189 | struct inode *inode; | |
0b2bac2f | 2190 | struct file *f; |
1da177e4 LT |
2191 | int error; |
2192 | ||
2193 | if (file_lock == NULL) | |
2194 | return -ENOLCK; | |
2195 | ||
2196 | /* | |
2197 | * This might block, so we do it before checking the inode. | |
2198 | */ | |
2199 | error = -EFAULT; | |
2200 | if (copy_from_user(&flock, l, sizeof(flock))) | |
2201 | goto out; | |
2202 | ||
496ad9aa | 2203 | inode = file_inode(filp); |
1da177e4 LT |
2204 | |
2205 | /* Don't allow mandatory locks on files that may be memory mapped | |
2206 | * and shared. | |
2207 | */ | |
a16877ca | 2208 | if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { |
1da177e4 LT |
2209 | error = -EAGAIN; |
2210 | goto out; | |
2211 | } | |
2212 | ||
c293621b | 2213 | again: |
1da177e4 LT |
2214 | error = flock64_to_posix_lock(filp, file_lock, &flock); |
2215 | if (error) | |
2216 | goto out; | |
5d50ffd7 | 2217 | |
cf01f4ee JL |
2218 | error = check_fmode_for_setlk(file_lock); |
2219 | if (error) | |
2220 | goto out; | |
2221 | ||
5d50ffd7 JL |
2222 | /* |
2223 | * If the cmd is requesting file-private locks, then set the | |
cff2fce5 | 2224 | * FL_OFDLCK flag and override the owner. |
5d50ffd7 JL |
2225 | */ |
2226 | switch (cmd) { | |
0d3f7a2d | 2227 | case F_OFD_SETLK: |
90478939 JL |
2228 | error = -EINVAL; |
2229 | if (flock.l_pid != 0) | |
2230 | goto out; | |
2231 | ||
5d50ffd7 | 2232 | cmd = F_SETLK64; |
cff2fce5 | 2233 | file_lock->fl_flags |= FL_OFDLCK; |
5d50ffd7 JL |
2234 | file_lock->fl_owner = (fl_owner_t)filp; |
2235 | break; | |
0d3f7a2d | 2236 | case F_OFD_SETLKW: |
90478939 JL |
2237 | error = -EINVAL; |
2238 | if (flock.l_pid != 0) | |
2239 | goto out; | |
2240 | ||
5d50ffd7 | 2241 | cmd = F_SETLKW64; |
cff2fce5 | 2242 | file_lock->fl_flags |= FL_OFDLCK; |
5d50ffd7 JL |
2243 | file_lock->fl_owner = (fl_owner_t)filp; |
2244 | /* Fallthrough */ | |
2245 | case F_SETLKW64: | |
1da177e4 LT |
2246 | file_lock->fl_flags |= FL_SLEEP; |
2247 | } | |
5d50ffd7 | 2248 | |
b648a6de | 2249 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2250 | |
c293621b PS |
2251 | /* |
2252 | * Attempt to detect a close/fcntl race and recover by | |
2253 | * releasing the lock that was just acquired. | |
2254 | */ | |
0b2bac2f AV |
2255 | spin_lock(¤t->files->file_lock); |
2256 | f = fcheck(fd); | |
2257 | spin_unlock(¤t->files->file_lock); | |
2258 | if (!error && f != filp && flock.l_type != F_UNLCK) { | |
c293621b PS |
2259 | flock.l_type = F_UNLCK; |
2260 | goto again; | |
1da177e4 LT |
2261 | } |
2262 | ||
2263 | out: | |
2264 | locks_free_lock(file_lock); | |
2265 | return error; | |
2266 | } | |
2267 | #endif /* BITS_PER_LONG == 32 */ | |
2268 | ||
2269 | /* | |
2270 | * This function is called when the file is being removed | |
2271 | * from the task's fd array. POSIX locks belonging to this task | |
2272 | * are deleted at this time. | |
2273 | */ | |
2274 | void locks_remove_posix(struct file *filp, fl_owner_t owner) | |
2275 | { | |
ff7b86b8 | 2276 | struct file_lock lock; |
1da177e4 LT |
2277 | |
2278 | /* | |
2279 | * If there are no locks held on this file, we don't need to call | |
2280 | * posix_lock_file(). Another process could be setting a lock on this | |
2281 | * file at the same time, but we wouldn't remove that lock anyway. | |
2282 | */ | |
496ad9aa | 2283 | if (!file_inode(filp)->i_flock) |
1da177e4 LT |
2284 | return; |
2285 | ||
2286 | lock.fl_type = F_UNLCK; | |
75e1fcc0 | 2287 | lock.fl_flags = FL_POSIX | FL_CLOSE; |
1da177e4 LT |
2288 | lock.fl_start = 0; |
2289 | lock.fl_end = OFFSET_MAX; | |
2290 | lock.fl_owner = owner; | |
2291 | lock.fl_pid = current->tgid; | |
2292 | lock.fl_file = filp; | |
2293 | lock.fl_ops = NULL; | |
2294 | lock.fl_lmops = NULL; | |
2295 | ||
150b3934 | 2296 | vfs_lock_file(filp, F_SETLK, &lock, NULL); |
1da177e4 | 2297 | |
1da177e4 LT |
2298 | if (lock.fl_ops && lock.fl_ops->fl_release_private) |
2299 | lock.fl_ops->fl_release_private(&lock); | |
2300 | } | |
2301 | ||
2302 | EXPORT_SYMBOL(locks_remove_posix); | |
2303 | ||
2304 | /* | |
2305 | * This function is called on the last close of an open file. | |
2306 | */ | |
78ed8a13 | 2307 | void locks_remove_file(struct file *filp) |
1da177e4 | 2308 | { |
496ad9aa | 2309 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
2310 | struct file_lock *fl; |
2311 | struct file_lock **before; | |
2312 | ||
2313 | if (!inode->i_flock) | |
2314 | return; | |
2315 | ||
5d50ffd7 JL |
2316 | locks_remove_posix(filp, (fl_owner_t)filp); |
2317 | ||
72c2d531 | 2318 | if (filp->f_op->flock) { |
1da177e4 | 2319 | struct file_lock fl = { |
130d1f95 | 2320 | .fl_owner = (fl_owner_t)filp, |
1da177e4 LT |
2321 | .fl_pid = current->tgid, |
2322 | .fl_file = filp, | |
2323 | .fl_flags = FL_FLOCK, | |
2324 | .fl_type = F_UNLCK, | |
2325 | .fl_end = OFFSET_MAX, | |
2326 | }; | |
2327 | filp->f_op->flock(filp, F_SETLKW, &fl); | |
80fec4c6 TM |
2328 | if (fl.fl_ops && fl.fl_ops->fl_release_private) |
2329 | fl.fl_ops->fl_release_private(&fl); | |
1da177e4 LT |
2330 | } |
2331 | ||
1c8c601a | 2332 | spin_lock(&inode->i_lock); |
1da177e4 LT |
2333 | before = &inode->i_flock; |
2334 | ||
2335 | while ((fl = *before) != NULL) { | |
2336 | if (fl->fl_file == filp) { | |
1da177e4 LT |
2337 | if (IS_LEASE(fl)) { |
2338 | lease_modify(before, F_UNLCK); | |
2339 | continue; | |
2340 | } | |
8c3cac5e JL |
2341 | |
2342 | /* | |
2343 | * There's a leftover lock on the list of a type that | |
2344 | * we didn't expect to see. Most likely a classic | |
2345 | * POSIX lock that ended up not getting released | |
2346 | * properly, or that raced onto the list somehow. Log | |
2347 | * some info about it and then just remove it from | |
2348 | * the list. | |
2349 | */ | |
2350 | WARN(!IS_FLOCK(fl), | |
2351 | "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n", | |
2352 | MAJOR(inode->i_sb->s_dev), | |
2353 | MINOR(inode->i_sb->s_dev), inode->i_ino, | |
2354 | fl->fl_type, fl->fl_flags, | |
2355 | fl->fl_start, fl->fl_end); | |
2356 | ||
2357 | locks_delete_lock(before); | |
2358 | continue; | |
1da177e4 LT |
2359 | } |
2360 | before = &fl->fl_next; | |
2361 | } | |
1c8c601a | 2362 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2363 | } |
2364 | ||
1da177e4 LT |
2365 | /** |
2366 | * posix_unblock_lock - stop waiting for a file lock | |
1da177e4 LT |
2367 | * @waiter: the lock which was waiting |
2368 | * | |
2369 | * lockd needs to block waiting for locks. | |
2370 | */ | |
64a318ee | 2371 | int |
f891a29f | 2372 | posix_unblock_lock(struct file_lock *waiter) |
1da177e4 | 2373 | { |
64a318ee BF |
2374 | int status = 0; |
2375 | ||
7b2296af | 2376 | spin_lock(&blocked_lock_lock); |
5996a298 | 2377 | if (waiter->fl_next) |
1da177e4 | 2378 | __locks_delete_block(waiter); |
64a318ee BF |
2379 | else |
2380 | status = -ENOENT; | |
7b2296af | 2381 | spin_unlock(&blocked_lock_lock); |
64a318ee | 2382 | return status; |
1da177e4 | 2383 | } |
1da177e4 LT |
2384 | EXPORT_SYMBOL(posix_unblock_lock); |
2385 | ||
9b9d2ab4 ME |
2386 | /** |
2387 | * vfs_cancel_lock - file byte range unblock lock | |
2388 | * @filp: The file to apply the unblock to | |
2389 | * @fl: The lock to be unblocked | |
2390 | * | |
2391 | * Used by lock managers to cancel blocked requests | |
2392 | */ | |
2393 | int vfs_cancel_lock(struct file *filp, struct file_lock *fl) | |
2394 | { | |
72c2d531 | 2395 | if (filp->f_op->lock) |
9b9d2ab4 ME |
2396 | return filp->f_op->lock(filp, F_CANCELLK, fl); |
2397 | return 0; | |
2398 | } | |
2399 | ||
2400 | EXPORT_SYMBOL_GPL(vfs_cancel_lock); | |
2401 | ||
7f8ada98 | 2402 | #ifdef CONFIG_PROC_FS |
d8ba7a36 | 2403 | #include <linux/proc_fs.h> |
7f8ada98 PE |
2404 | #include <linux/seq_file.h> |
2405 | ||
7012b02a JL |
2406 | struct locks_iterator { |
2407 | int li_cpu; | |
2408 | loff_t li_pos; | |
2409 | }; | |
2410 | ||
7f8ada98 | 2411 | static void lock_get_status(struct seq_file *f, struct file_lock *fl, |
99dc8292 | 2412 | loff_t id, char *pfx) |
1da177e4 LT |
2413 | { |
2414 | struct inode *inode = NULL; | |
ab1f1611 VG |
2415 | unsigned int fl_pid; |
2416 | ||
2417 | if (fl->fl_nspid) | |
6c5f3e7b | 2418 | fl_pid = pid_vnr(fl->fl_nspid); |
ab1f1611 VG |
2419 | else |
2420 | fl_pid = fl->fl_pid; | |
1da177e4 LT |
2421 | |
2422 | if (fl->fl_file != NULL) | |
496ad9aa | 2423 | inode = file_inode(fl->fl_file); |
1da177e4 | 2424 | |
99dc8292 | 2425 | seq_printf(f, "%lld:%s ", id, pfx); |
1da177e4 | 2426 | if (IS_POSIX(fl)) { |
c918d42a | 2427 | if (fl->fl_flags & FL_ACCESS) |
5315c26a | 2428 | seq_puts(f, "ACCESS"); |
cff2fce5 | 2429 | else if (IS_OFDLCK(fl)) |
5315c26a | 2430 | seq_puts(f, "OFDLCK"); |
c918d42a | 2431 | else |
5315c26a | 2432 | seq_puts(f, "POSIX "); |
c918d42a JL |
2433 | |
2434 | seq_printf(f, " %s ", | |
1da177e4 | 2435 | (inode == NULL) ? "*NOINODE*" : |
a16877ca | 2436 | mandatory_lock(inode) ? "MANDATORY" : "ADVISORY "); |
1da177e4 LT |
2437 | } else if (IS_FLOCK(fl)) { |
2438 | if (fl->fl_type & LOCK_MAND) { | |
5315c26a | 2439 | seq_puts(f, "FLOCK MSNFS "); |
1da177e4 | 2440 | } else { |
5315c26a | 2441 | seq_puts(f, "FLOCK ADVISORY "); |
1da177e4 LT |
2442 | } |
2443 | } else if (IS_LEASE(fl)) { | |
5315c26a | 2444 | seq_puts(f, "LEASE "); |
ab83fa4b | 2445 | if (lease_breaking(fl)) |
5315c26a | 2446 | seq_puts(f, "BREAKING "); |
1da177e4 | 2447 | else if (fl->fl_file) |
5315c26a | 2448 | seq_puts(f, "ACTIVE "); |
1da177e4 | 2449 | else |
5315c26a | 2450 | seq_puts(f, "BREAKER "); |
1da177e4 | 2451 | } else { |
5315c26a | 2452 | seq_puts(f, "UNKNOWN UNKNOWN "); |
1da177e4 LT |
2453 | } |
2454 | if (fl->fl_type & LOCK_MAND) { | |
7f8ada98 | 2455 | seq_printf(f, "%s ", |
1da177e4 LT |
2456 | (fl->fl_type & LOCK_READ) |
2457 | ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ " | |
2458 | : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE "); | |
2459 | } else { | |
7f8ada98 | 2460 | seq_printf(f, "%s ", |
ab83fa4b | 2461 | (lease_breaking(fl)) |
0ee5c6d6 JL |
2462 | ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ " |
2463 | : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ "); | |
1da177e4 LT |
2464 | } |
2465 | if (inode) { | |
2466 | #ifdef WE_CAN_BREAK_LSLK_NOW | |
ab1f1611 | 2467 | seq_printf(f, "%d %s:%ld ", fl_pid, |
1da177e4 LT |
2468 | inode->i_sb->s_id, inode->i_ino); |
2469 | #else | |
2470 | /* userspace relies on this representation of dev_t ;-( */ | |
ab1f1611 | 2471 | seq_printf(f, "%d %02x:%02x:%ld ", fl_pid, |
1da177e4 LT |
2472 | MAJOR(inode->i_sb->s_dev), |
2473 | MINOR(inode->i_sb->s_dev), inode->i_ino); | |
2474 | #endif | |
2475 | } else { | |
ab1f1611 | 2476 | seq_printf(f, "%d <none>:0 ", fl_pid); |
1da177e4 LT |
2477 | } |
2478 | if (IS_POSIX(fl)) { | |
2479 | if (fl->fl_end == OFFSET_MAX) | |
7f8ada98 | 2480 | seq_printf(f, "%Ld EOF\n", fl->fl_start); |
1da177e4 | 2481 | else |
7f8ada98 | 2482 | seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end); |
1da177e4 | 2483 | } else { |
5315c26a | 2484 | seq_puts(f, "0 EOF\n"); |
1da177e4 LT |
2485 | } |
2486 | } | |
2487 | ||
7f8ada98 | 2488 | static int locks_show(struct seq_file *f, void *v) |
1da177e4 | 2489 | { |
7012b02a | 2490 | struct locks_iterator *iter = f->private; |
7f8ada98 | 2491 | struct file_lock *fl, *bfl; |
1da177e4 | 2492 | |
139ca04e | 2493 | fl = hlist_entry(v, struct file_lock, fl_link); |
1da177e4 | 2494 | |
7012b02a | 2495 | lock_get_status(f, fl, iter->li_pos, ""); |
1da177e4 | 2496 | |
7f8ada98 | 2497 | list_for_each_entry(bfl, &fl->fl_block, fl_block) |
7012b02a | 2498 | lock_get_status(f, bfl, iter->li_pos, " ->"); |
094f2825 | 2499 | |
7f8ada98 PE |
2500 | return 0; |
2501 | } | |
1da177e4 | 2502 | |
7f8ada98 | 2503 | static void *locks_start(struct seq_file *f, loff_t *pos) |
b03dfdec | 2504 | __acquires(&blocked_lock_lock) |
7f8ada98 | 2505 | { |
7012b02a | 2506 | struct locks_iterator *iter = f->private; |
99dc8292 | 2507 | |
7012b02a JL |
2508 | iter->li_pos = *pos + 1; |
2509 | lg_global_lock(&file_lock_lglock); | |
7b2296af | 2510 | spin_lock(&blocked_lock_lock); |
7012b02a | 2511 | return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos); |
7f8ada98 | 2512 | } |
1da177e4 | 2513 | |
7f8ada98 PE |
2514 | static void *locks_next(struct seq_file *f, void *v, loff_t *pos) |
2515 | { | |
7012b02a JL |
2516 | struct locks_iterator *iter = f->private; |
2517 | ||
2518 | ++iter->li_pos; | |
2519 | return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos); | |
7f8ada98 | 2520 | } |
1da177e4 | 2521 | |
7f8ada98 | 2522 | static void locks_stop(struct seq_file *f, void *v) |
b03dfdec | 2523 | __releases(&blocked_lock_lock) |
7f8ada98 | 2524 | { |
7b2296af | 2525 | spin_unlock(&blocked_lock_lock); |
7012b02a | 2526 | lg_global_unlock(&file_lock_lglock); |
1da177e4 LT |
2527 | } |
2528 | ||
d8ba7a36 | 2529 | static const struct seq_operations locks_seq_operations = { |
7f8ada98 PE |
2530 | .start = locks_start, |
2531 | .next = locks_next, | |
2532 | .stop = locks_stop, | |
2533 | .show = locks_show, | |
2534 | }; | |
d8ba7a36 AD |
2535 | |
2536 | static int locks_open(struct inode *inode, struct file *filp) | |
2537 | { | |
7012b02a JL |
2538 | return seq_open_private(filp, &locks_seq_operations, |
2539 | sizeof(struct locks_iterator)); | |
d8ba7a36 AD |
2540 | } |
2541 | ||
2542 | static const struct file_operations proc_locks_operations = { | |
2543 | .open = locks_open, | |
2544 | .read = seq_read, | |
2545 | .llseek = seq_lseek, | |
99dc8292 | 2546 | .release = seq_release_private, |
d8ba7a36 AD |
2547 | }; |
2548 | ||
2549 | static int __init proc_locks_init(void) | |
2550 | { | |
2551 | proc_create("locks", 0, NULL, &proc_locks_operations); | |
2552 | return 0; | |
2553 | } | |
2554 | module_init(proc_locks_init); | |
7f8ada98 PE |
2555 | #endif |
2556 | ||
1da177e4 LT |
2557 | /** |
2558 | * lock_may_read - checks that the region is free of locks | |
2559 | * @inode: the inode that is being read | |
2560 | * @start: the first byte to read | |
2561 | * @len: the number of bytes to read | |
2562 | * | |
2563 | * Emulates Windows locking requirements. Whole-file | |
2564 | * mandatory locks (share modes) can prohibit a read and | |
2565 | * byte-range POSIX locks can prohibit a read if they overlap. | |
2566 | * | |
2567 | * N.B. this function is only ever called | |
2568 | * from knfsd and ownership of locks is never checked. | |
2569 | */ | |
2570 | int lock_may_read(struct inode *inode, loff_t start, unsigned long len) | |
2571 | { | |
2572 | struct file_lock *fl; | |
2573 | int result = 1; | |
1c8c601a JL |
2574 | |
2575 | spin_lock(&inode->i_lock); | |
1da177e4 LT |
2576 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
2577 | if (IS_POSIX(fl)) { | |
2578 | if (fl->fl_type == F_RDLCK) | |
2579 | continue; | |
2580 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2581 | continue; | |
2582 | } else if (IS_FLOCK(fl)) { | |
2583 | if (!(fl->fl_type & LOCK_MAND)) | |
2584 | continue; | |
2585 | if (fl->fl_type & LOCK_READ) | |
2586 | continue; | |
2587 | } else | |
2588 | continue; | |
2589 | result = 0; | |
2590 | break; | |
2591 | } | |
1c8c601a | 2592 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2593 | return result; |
2594 | } | |
2595 | ||
2596 | EXPORT_SYMBOL(lock_may_read); | |
2597 | ||
2598 | /** | |
2599 | * lock_may_write - checks that the region is free of locks | |
2600 | * @inode: the inode that is being written | |
2601 | * @start: the first byte to write | |
2602 | * @len: the number of bytes to write | |
2603 | * | |
2604 | * Emulates Windows locking requirements. Whole-file | |
2605 | * mandatory locks (share modes) can prohibit a write and | |
2606 | * byte-range POSIX locks can prohibit a write if they overlap. | |
2607 | * | |
2608 | * N.B. this function is only ever called | |
2609 | * from knfsd and ownership of locks is never checked. | |
2610 | */ | |
2611 | int lock_may_write(struct inode *inode, loff_t start, unsigned long len) | |
2612 | { | |
2613 | struct file_lock *fl; | |
2614 | int result = 1; | |
1c8c601a JL |
2615 | |
2616 | spin_lock(&inode->i_lock); | |
1da177e4 LT |
2617 | for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) { |
2618 | if (IS_POSIX(fl)) { | |
2619 | if ((fl->fl_end < start) || (fl->fl_start > (start + len))) | |
2620 | continue; | |
2621 | } else if (IS_FLOCK(fl)) { | |
2622 | if (!(fl->fl_type & LOCK_MAND)) | |
2623 | continue; | |
2624 | if (fl->fl_type & LOCK_WRITE) | |
2625 | continue; | |
2626 | } else | |
2627 | continue; | |
2628 | result = 0; | |
2629 | break; | |
2630 | } | |
1c8c601a | 2631 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
2632 | return result; |
2633 | } | |
2634 | ||
2635 | EXPORT_SYMBOL(lock_may_write); | |
2636 | ||
1da177e4 LT |
2637 | static int __init filelock_init(void) |
2638 | { | |
7012b02a JL |
2639 | int i; |
2640 | ||
1da177e4 | 2641 | filelock_cache = kmem_cache_create("file_lock_cache", |
ee19cc40 MS |
2642 | sizeof(struct file_lock), 0, SLAB_PANIC, NULL); |
2643 | ||
7012b02a JL |
2644 | lg_lock_init(&file_lock_lglock, "file_lock_lglock"); |
2645 | ||
2646 | for_each_possible_cpu(i) | |
2647 | INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i)); | |
2648 | ||
1da177e4 LT |
2649 | return 0; |
2650 | } | |
2651 | ||
2652 | core_initcall(filelock_init); |