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CommitLineData
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>
1da177e4
LT
122#include <linux/security.h>
123#include <linux/slab.h>
1da177e4
LT
124#include <linux/syscalls.h>
125#include <linux/time.h>
4fb3a538 126#include <linux/rcupdate.h>
ab1f1611 127#include <linux/pid_namespace.h>
48f74186 128#include <linux/hashtable.h>
7012b02a
JL
129#include <linux/percpu.h>
130#include <linux/lglock.h>
1da177e4 131
62af4f1f
JL
132#define CREATE_TRACE_POINTS
133#include <trace/events/filelock.h>
134
1da177e4
LT
135#include <asm/uaccess.h>
136
137#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
138#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
11afe9f7 139#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
cff2fce5 140#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
1da177e4 141
ab83fa4b
BF
142static bool lease_breaking(struct file_lock *fl)
143{
778fc546
BF
144 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
145}
146
147static int target_leasetype(struct file_lock *fl)
148{
149 if (fl->fl_flags & FL_UNLOCK_PENDING)
150 return F_UNLCK;
151 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
152 return F_RDLCK;
153 return fl->fl_type;
ab83fa4b
BF
154}
155
1da177e4
LT
156int leases_enable = 1;
157int lease_break_time = 45;
158
1c8c601a 159/*
7012b02a
JL
160 * The global file_lock_list is only used for displaying /proc/locks, so we
161 * keep a list on each CPU, with each list protected by its own spinlock via
162 * the file_lock_lglock. Note that alterations to the list also require that
6109c850 163 * the relevant flc_lock is held.
1c8c601a 164 */
7012b02a
JL
165DEFINE_STATIC_LGLOCK(file_lock_lglock);
166static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
88974691 167
1c8c601a 168/*
48f74186 169 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
7b2296af 170 * It is protected by blocked_lock_lock.
48f74186
JL
171 *
172 * We hash locks by lockowner in order to optimize searching for the lock a
173 * particular lockowner is waiting on.
174 *
175 * FIXME: make this value scale via some heuristic? We generally will want more
176 * buckets when we have more lockowners holding locks, but that's a little
177 * difficult to determine without knowing what the workload will look like.
1c8c601a 178 */
48f74186
JL
179#define BLOCKED_HASH_BITS 7
180static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
88974691 181
1c8c601a 182/*
7b2296af
JL
183 * This lock protects the blocked_hash. Generally, if you're accessing it, you
184 * want to be holding this lock.
1c8c601a
JL
185 *
186 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
187 * pointer for file_lock structures that are acting as lock requests (in
188 * contrast to those that are acting as records of acquired locks).
189 *
190 * Note that when we acquire this lock in order to change the above fields,
6109c850 191 * we often hold the flc_lock as well. In certain cases, when reading the fields
1c8c601a 192 * protected by this lock, we can skip acquiring it iff we already hold the
6109c850 193 * flc_lock.
1c8c601a
JL
194 *
195 * In particular, adding an entry to the fl_block list requires that you hold
6109c850
JL
196 * both the flc_lock and the blocked_lock_lock (acquired in that order).
197 * Deleting an entry from the list however only requires the file_lock_lock.
1c8c601a 198 */
7b2296af 199static DEFINE_SPINLOCK(blocked_lock_lock);
1da177e4 200
4a075e39 201static struct kmem_cache *flctx_cache __read_mostly;
e18b890b 202static struct kmem_cache *filelock_cache __read_mostly;
1da177e4 203
4a075e39 204static struct file_lock_context *
5c1c669a 205locks_get_lock_context(struct inode *inode, int type)
4a075e39 206{
128a3785 207 struct file_lock_context *ctx;
4a075e39 208
128a3785
DV
209 /* paired with cmpxchg() below */
210 ctx = smp_load_acquire(&inode->i_flctx);
211 if (likely(ctx) || type == F_UNLCK)
4a075e39
JL
212 goto out;
213
128a3785
DV
214 ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
215 if (!ctx)
4a075e39
JL
216 goto out;
217
128a3785
DV
218 spin_lock_init(&ctx->flc_lock);
219 INIT_LIST_HEAD(&ctx->flc_flock);
220 INIT_LIST_HEAD(&ctx->flc_posix);
221 INIT_LIST_HEAD(&ctx->flc_lease);
4a075e39
JL
222
223 /*
224 * Assign the pointer if it's not already assigned. If it is, then
225 * free the context we just allocated.
226 */
128a3785
DV
227 if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
228 kmem_cache_free(flctx_cache, ctx);
229 ctx = smp_load_acquire(&inode->i_flctx);
230 }
4a075e39 231out:
1890910f 232 trace_locks_get_lock_context(inode, type, ctx);
128a3785 233 return ctx;
4a075e39
JL
234}
235
e24dadab
JL
236static void
237locks_dump_ctx_list(struct list_head *list, char *list_type)
238{
239 struct file_lock *fl;
240
241 list_for_each_entry(fl, list, fl_list) {
242 pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
243 }
244}
245
246static void
247locks_check_ctx_lists(struct inode *inode)
248{
249 struct file_lock_context *ctx = inode->i_flctx;
250
251 if (unlikely(!list_empty(&ctx->flc_flock) ||
252 !list_empty(&ctx->flc_posix) ||
253 !list_empty(&ctx->flc_lease))) {
254 pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
255 MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
256 inode->i_ino);
257 locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
258 locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
259 locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
260 }
261}
262
4a075e39 263void
f27a0fe0 264locks_free_lock_context(struct inode *inode)
4a075e39 265{
f27a0fe0
JL
266 struct file_lock_context *ctx = inode->i_flctx;
267
e24dadab
JL
268 if (unlikely(ctx)) {
269 locks_check_ctx_lists(inode);
4a075e39
JL
270 kmem_cache_free(flctx_cache, ctx);
271 }
272}
273
ee19cc40 274static void locks_init_lock_heads(struct file_lock *fl)
a51cb91d 275{
139ca04e 276 INIT_HLIST_NODE(&fl->fl_link);
6dee60f6 277 INIT_LIST_HEAD(&fl->fl_list);
ee19cc40
MS
278 INIT_LIST_HEAD(&fl->fl_block);
279 init_waitqueue_head(&fl->fl_wait);
a51cb91d
MS
280}
281
1da177e4 282/* Allocate an empty lock structure. */
c5b1f0d9 283struct file_lock *locks_alloc_lock(void)
1da177e4 284{
ee19cc40 285 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
a51cb91d
MS
286
287 if (fl)
ee19cc40 288 locks_init_lock_heads(fl);
a51cb91d
MS
289
290 return fl;
1da177e4 291}
c5b1f0d9 292EXPORT_SYMBOL_GPL(locks_alloc_lock);
1da177e4 293
a9e61e25 294void locks_release_private(struct file_lock *fl)
47831f35
TM
295{
296 if (fl->fl_ops) {
297 if (fl->fl_ops->fl_release_private)
298 fl->fl_ops->fl_release_private(fl);
299 fl->fl_ops = NULL;
300 }
47831f35 301
5c97d7b1 302 if (fl->fl_lmops) {
cae80b30
JL
303 if (fl->fl_lmops->lm_put_owner) {
304 fl->fl_lmops->lm_put_owner(fl->fl_owner);
305 fl->fl_owner = NULL;
306 }
5c97d7b1
KM
307 fl->fl_lmops = NULL;
308 }
47831f35 309}
a9e61e25 310EXPORT_SYMBOL_GPL(locks_release_private);
47831f35 311
1da177e4 312/* Free a lock which is not in use. */
05fa3135 313void locks_free_lock(struct file_lock *fl)
1da177e4 314{
5ce29646 315 BUG_ON(waitqueue_active(&fl->fl_wait));
6dee60f6 316 BUG_ON(!list_empty(&fl->fl_list));
5ce29646 317 BUG_ON(!list_empty(&fl->fl_block));
139ca04e 318 BUG_ON(!hlist_unhashed(&fl->fl_link));
1da177e4 319
47831f35 320 locks_release_private(fl);
1da177e4
LT
321 kmem_cache_free(filelock_cache, fl);
322}
05fa3135 323EXPORT_SYMBOL(locks_free_lock);
1da177e4 324
ed9814d8
JL
325static void
326locks_dispose_list(struct list_head *dispose)
327{
328 struct file_lock *fl;
329
330 while (!list_empty(dispose)) {
6dee60f6
JL
331 fl = list_first_entry(dispose, struct file_lock, fl_list);
332 list_del_init(&fl->fl_list);
ed9814d8
JL
333 locks_free_lock(fl);
334 }
335}
336
1da177e4
LT
337void locks_init_lock(struct file_lock *fl)
338{
ee19cc40
MS
339 memset(fl, 0, sizeof(struct file_lock));
340 locks_init_lock_heads(fl);
1da177e4
LT
341}
342
343EXPORT_SYMBOL(locks_init_lock);
344
1da177e4
LT
345/*
346 * Initialize a new lock from an existing file_lock structure.
347 */
3fe0fff1 348void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
1da177e4
LT
349{
350 new->fl_owner = fl->fl_owner;
351 new->fl_pid = fl->fl_pid;
0996905f 352 new->fl_file = NULL;
1da177e4
LT
353 new->fl_flags = fl->fl_flags;
354 new->fl_type = fl->fl_type;
355 new->fl_start = fl->fl_start;
356 new->fl_end = fl->fl_end;
f328296e 357 new->fl_lmops = fl->fl_lmops;
0996905f 358 new->fl_ops = NULL;
f328296e
KM
359
360 if (fl->fl_lmops) {
361 if (fl->fl_lmops->lm_get_owner)
cae80b30 362 fl->fl_lmops->lm_get_owner(fl->fl_owner);
f328296e 363 }
0996905f 364}
3fe0fff1 365EXPORT_SYMBOL(locks_copy_conflock);
0996905f
TM
366
367void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
368{
566709bd
JL
369 /* "new" must be a freshly-initialized lock */
370 WARN_ON_ONCE(new->fl_ops);
0996905f 371
3fe0fff1 372 locks_copy_conflock(new, fl);
f328296e 373
0996905f 374 new->fl_file = fl->fl_file;
1da177e4 375 new->fl_ops = fl->fl_ops;
47831f35 376
f328296e
KM
377 if (fl->fl_ops) {
378 if (fl->fl_ops->fl_copy_lock)
379 fl->fl_ops->fl_copy_lock(new, fl);
380 }
1da177e4
LT
381}
382
383EXPORT_SYMBOL(locks_copy_lock);
384
385static inline int flock_translate_cmd(int cmd) {
386 if (cmd & LOCK_MAND)
387 return cmd & (LOCK_MAND | LOCK_RW);
388 switch (cmd) {
389 case LOCK_SH:
390 return F_RDLCK;
391 case LOCK_EX:
392 return F_WRLCK;
393 case LOCK_UN:
394 return F_UNLCK;
395 }
396 return -EINVAL;
397}
398
399/* Fill in a file_lock structure with an appropriate FLOCK lock. */
6e129d00
JL
400static struct file_lock *
401flock_make_lock(struct file *filp, unsigned int cmd)
1da177e4
LT
402{
403 struct file_lock *fl;
404 int type = flock_translate_cmd(cmd);
6e129d00 405
1da177e4 406 if (type < 0)
6e129d00 407 return ERR_PTR(type);
1da177e4
LT
408
409 fl = locks_alloc_lock();
410 if (fl == NULL)
6e129d00 411 return ERR_PTR(-ENOMEM);
1da177e4
LT
412
413 fl->fl_file = filp;
73a8f5f7 414 fl->fl_owner = filp;
1da177e4
LT
415 fl->fl_pid = current->tgid;
416 fl->fl_flags = FL_FLOCK;
417 fl->fl_type = type;
418 fl->fl_end = OFFSET_MAX;
419
6e129d00 420 return fl;
1da177e4
LT
421}
422
0ec4f431 423static int assign_type(struct file_lock *fl, long type)
1da177e4
LT
424{
425 switch (type) {
426 case F_RDLCK:
427 case F_WRLCK:
428 case F_UNLCK:
429 fl->fl_type = type;
430 break;
431 default:
432 return -EINVAL;
433 }
434 return 0;
435}
436
ef12e72a
BF
437static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
438 struct flock64 *l)
1da177e4 439{
1da177e4 440 switch (l->l_whence) {
f5579f8c 441 case SEEK_SET:
ef12e72a 442 fl->fl_start = 0;
1da177e4 443 break;
f5579f8c 444 case SEEK_CUR:
ef12e72a 445 fl->fl_start = filp->f_pos;
1da177e4 446 break;
f5579f8c 447 case SEEK_END:
ef12e72a 448 fl->fl_start = i_size_read(file_inode(filp));
1da177e4
LT
449 break;
450 default:
451 return -EINVAL;
452 }
ef12e72a
BF
453 if (l->l_start > OFFSET_MAX - fl->fl_start)
454 return -EOVERFLOW;
455 fl->fl_start += l->l_start;
456 if (fl->fl_start < 0)
457 return -EINVAL;
1da177e4
LT
458
459 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
460 POSIX-2001 defines it. */
4c780a46 461 if (l->l_len > 0) {
ef12e72a
BF
462 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
463 return -EOVERFLOW;
464 fl->fl_end = fl->fl_start + l->l_len - 1;
465
4c780a46 466 } else if (l->l_len < 0) {
ef12e72a 467 if (fl->fl_start + l->l_len < 0)
4c780a46 468 return -EINVAL;
ef12e72a
BF
469 fl->fl_end = fl->fl_start - 1;
470 fl->fl_start += l->l_len;
471 } else
472 fl->fl_end = OFFSET_MAX;
473
1da177e4
LT
474 fl->fl_owner = current->files;
475 fl->fl_pid = current->tgid;
476 fl->fl_file = filp;
477 fl->fl_flags = FL_POSIX;
478 fl->fl_ops = NULL;
479 fl->fl_lmops = NULL;
480
481 return assign_type(fl, l->l_type);
482}
483
ef12e72a
BF
484/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
485 * style lock.
486 */
487static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
488 struct flock *l)
1da177e4 489{
ef12e72a
BF
490 struct flock64 ll = {
491 .l_type = l->l_type,
492 .l_whence = l->l_whence,
493 .l_start = l->l_start,
494 .l_len = l->l_len,
495 };
496
497 return flock64_to_posix_lock(filp, fl, &ll);
1da177e4 498}
1da177e4
LT
499
500/* default lease lock manager operations */
4d01b7f5
JL
501static bool
502lease_break_callback(struct file_lock *fl)
1da177e4
LT
503{
504 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
4d01b7f5 505 return false;
1da177e4
LT
506}
507
1c7dd2ff
JL
508static void
509lease_setup(struct file_lock *fl, void **priv)
510{
511 struct file *filp = fl->fl_file;
512 struct fasync_struct *fa = *priv;
513
514 /*
515 * fasync_insert_entry() returns the old entry if any. If there was no
516 * old entry, then it used "priv" and inserted it into the fasync list.
517 * Clear the pointer to indicate that it shouldn't be freed.
518 */
519 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
520 *priv = NULL;
521
522 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
523}
524
7b021967 525static const struct lock_manager_operations lease_manager_ops = {
8fb47a4f 526 .lm_break = lease_break_callback,
8fb47a4f 527 .lm_change = lease_modify,
1c7dd2ff 528 .lm_setup = lease_setup,
1da177e4
LT
529};
530
531/*
532 * Initialize a lease, use the default lock manager operations
533 */
0ec4f431 534static int lease_init(struct file *filp, long type, struct file_lock *fl)
1da177e4 535 {
75dff55a
TM
536 if (assign_type(fl, type) != 0)
537 return -EINVAL;
538
7ca76311 539 fl->fl_owner = filp;
1da177e4
LT
540 fl->fl_pid = current->tgid;
541
542 fl->fl_file = filp;
543 fl->fl_flags = FL_LEASE;
1da177e4
LT
544 fl->fl_start = 0;
545 fl->fl_end = OFFSET_MAX;
546 fl->fl_ops = NULL;
547 fl->fl_lmops = &lease_manager_ops;
548 return 0;
549}
550
551/* Allocate a file_lock initialised to this type of lease */
0ec4f431 552static struct file_lock *lease_alloc(struct file *filp, long type)
1da177e4
LT
553{
554 struct file_lock *fl = locks_alloc_lock();
75dff55a 555 int error = -ENOMEM;
1da177e4
LT
556
557 if (fl == NULL)
e32b8ee2 558 return ERR_PTR(error);
1da177e4
LT
559
560 error = lease_init(filp, type, fl);
75dff55a
TM
561 if (error) {
562 locks_free_lock(fl);
e32b8ee2 563 return ERR_PTR(error);
75dff55a 564 }
e32b8ee2 565 return fl;
1da177e4
LT
566}
567
568/* Check if two locks overlap each other.
569 */
570static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
571{
572 return ((fl1->fl_end >= fl2->fl_start) &&
573 (fl2->fl_end >= fl1->fl_start));
574}
575
576/*
577 * Check whether two locks have the same owner.
578 */
33443c42 579static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
1da177e4 580{
8fb47a4f 581 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
1da177e4 582 return fl2->fl_lmops == fl1->fl_lmops &&
8fb47a4f 583 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
1da177e4
LT
584 return fl1->fl_owner == fl2->fl_owner;
585}
586
6109c850 587/* Must be called with the flc_lock held! */
6ca10ed8 588static void locks_insert_global_locks(struct file_lock *fl)
88974691 589{
7012b02a
JL
590 lg_local_lock(&file_lock_lglock);
591 fl->fl_link_cpu = smp_processor_id();
592 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
593 lg_local_unlock(&file_lock_lglock);
88974691
JL
594}
595
6109c850 596/* Must be called with the flc_lock held! */
6ca10ed8 597static void locks_delete_global_locks(struct file_lock *fl)
88974691 598{
7012b02a
JL
599 /*
600 * Avoid taking lock if already unhashed. This is safe since this check
6109c850 601 * is done while holding the flc_lock, and new insertions into the list
7012b02a
JL
602 * also require that it be held.
603 */
604 if (hlist_unhashed(&fl->fl_link))
605 return;
606 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
139ca04e 607 hlist_del_init(&fl->fl_link);
7012b02a 608 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
88974691
JL
609}
610
3999e493
JL
611static unsigned long
612posix_owner_key(struct file_lock *fl)
613{
614 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
615 return fl->fl_lmops->lm_owner_key(fl);
616 return (unsigned long)fl->fl_owner;
617}
618
6ca10ed8 619static void locks_insert_global_blocked(struct file_lock *waiter)
88974691 620{
663d5af7
DW
621 lockdep_assert_held(&blocked_lock_lock);
622
3999e493 623 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
88974691
JL
624}
625
6ca10ed8 626static void locks_delete_global_blocked(struct file_lock *waiter)
88974691 627{
663d5af7
DW
628 lockdep_assert_held(&blocked_lock_lock);
629
48f74186 630 hash_del(&waiter->fl_link);
88974691
JL
631}
632
1da177e4
LT
633/* Remove waiter from blocker's block list.
634 * When blocker ends up pointing to itself then the list is empty.
1c8c601a 635 *
7b2296af 636 * Must be called with blocked_lock_lock held.
1da177e4 637 */
33443c42 638static void __locks_delete_block(struct file_lock *waiter)
1da177e4 639{
88974691 640 locks_delete_global_blocked(waiter);
1da177e4 641 list_del_init(&waiter->fl_block);
1da177e4
LT
642 waiter->fl_next = NULL;
643}
644
1a9e64a7 645static void locks_delete_block(struct file_lock *waiter)
1da177e4 646{
7b2296af 647 spin_lock(&blocked_lock_lock);
1da177e4 648 __locks_delete_block(waiter);
7b2296af 649 spin_unlock(&blocked_lock_lock);
1da177e4
LT
650}
651
652/* Insert waiter into blocker's block list.
653 * We use a circular list so that processes can be easily woken up in
654 * the order they blocked. The documentation doesn't require this but
655 * it seems like the reasonable thing to do.
1c8c601a 656 *
6109c850
JL
657 * Must be called with both the flc_lock and blocked_lock_lock held. The
658 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
659 * that the flc_lock is also held on insertions we can avoid taking the
660 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
1da177e4 661 */
1c8c601a
JL
662static void __locks_insert_block(struct file_lock *blocker,
663 struct file_lock *waiter)
1da177e4 664{
6dc0fe8f 665 BUG_ON(!list_empty(&waiter->fl_block));
1da177e4 666 waiter->fl_next = blocker;
88974691 667 list_add_tail(&waiter->fl_block, &blocker->fl_block);
cff2fce5 668 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
1c8c601a
JL
669 locks_insert_global_blocked(waiter);
670}
671
6109c850 672/* Must be called with flc_lock held. */
1c8c601a
JL
673static void locks_insert_block(struct file_lock *blocker,
674 struct file_lock *waiter)
675{
7b2296af 676 spin_lock(&blocked_lock_lock);
1c8c601a 677 __locks_insert_block(blocker, waiter);
7b2296af 678 spin_unlock(&blocked_lock_lock);
1da177e4
LT
679}
680
1cb36012
JL
681/*
682 * Wake up processes blocked waiting for blocker.
683 *
6109c850 684 * Must be called with the inode->flc_lock held!
1da177e4
LT
685 */
686static void locks_wake_up_blocks(struct file_lock *blocker)
687{
4e8c765d
JL
688 /*
689 * Avoid taking global lock if list is empty. This is safe since new
6109c850
JL
690 * blocked requests are only added to the list under the flc_lock, and
691 * the flc_lock is always held here. Note that removal from the fl_block
692 * list does not require the flc_lock, so we must recheck list_empty()
7b2296af 693 * after acquiring the blocked_lock_lock.
4e8c765d
JL
694 */
695 if (list_empty(&blocker->fl_block))
696 return;
697
7b2296af 698 spin_lock(&blocked_lock_lock);
1da177e4 699 while (!list_empty(&blocker->fl_block)) {
f0c1cd0e
PE
700 struct file_lock *waiter;
701
702 waiter = list_first_entry(&blocker->fl_block,
1da177e4
LT
703 struct file_lock, fl_block);
704 __locks_delete_block(waiter);
8fb47a4f
BF
705 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
706 waiter->fl_lmops->lm_notify(waiter);
1da177e4
LT
707 else
708 wake_up(&waiter->fl_wait);
709 }
7b2296af 710 spin_unlock(&blocked_lock_lock);
1da177e4
LT
711}
712
5263e31e 713static void
e084c1bd 714locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
5263e31e
JL
715{
716 fl->fl_nspid = get_pid(task_tgid(current));
717 list_add_tail(&fl->fl_list, before);
718 locks_insert_global_locks(fl);
719}
720
8634b51f 721static void
e084c1bd 722locks_unlink_lock_ctx(struct file_lock *fl)
1da177e4 723{
88974691 724 locks_delete_global_locks(fl);
8634b51f 725 list_del_init(&fl->fl_list);
ab1f1611
VG
726 if (fl->fl_nspid) {
727 put_pid(fl->fl_nspid);
728 fl->fl_nspid = NULL;
729 }
1da177e4 730 locks_wake_up_blocks(fl);
24cbe784
JL
731}
732
8634b51f 733static void
e084c1bd 734locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
24cbe784 735{
e084c1bd 736 locks_unlink_lock_ctx(fl);
ed9814d8 737 if (dispose)
6dee60f6 738 list_add(&fl->fl_list, dispose);
ed9814d8
JL
739 else
740 locks_free_lock(fl);
1da177e4
LT
741}
742
743/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
744 * checks for shared/exclusive status of overlapping locks.
745 */
746static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
747{
748 if (sys_fl->fl_type == F_WRLCK)
749 return 1;
750 if (caller_fl->fl_type == F_WRLCK)
751 return 1;
752 return 0;
753}
754
755/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
756 * checking before calling the locks_conflict().
757 */
758static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
759{
760 /* POSIX locks owned by the same process do not conflict with
761 * each other.
762 */
9b8c8695 763 if (posix_same_owner(caller_fl, sys_fl))
1da177e4
LT
764 return (0);
765
766 /* Check whether they overlap */
767 if (!locks_overlap(caller_fl, sys_fl))
768 return 0;
769
770 return (locks_conflict(caller_fl, sys_fl));
771}
772
773/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
774 * checking before calling the locks_conflict().
775 */
776static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
777{
778 /* FLOCK locks referring to the same filp do not conflict with
779 * each other.
780 */
9b8c8695 781 if (caller_fl->fl_file == sys_fl->fl_file)
1da177e4
LT
782 return (0);
783 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
784 return 0;
785
786 return (locks_conflict(caller_fl, sys_fl));
787}
788
6d34ac19 789void
9d6a8c5c 790posix_test_lock(struct file *filp, struct file_lock *fl)
1da177e4
LT
791{
792 struct file_lock *cfl;
bd61e0a9 793 struct file_lock_context *ctx;
1c8c601a 794 struct inode *inode = file_inode(filp);
1da177e4 795
128a3785 796 ctx = smp_load_acquire(&inode->i_flctx);
bd61e0a9
JL
797 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
798 fl->fl_type = F_UNLCK;
799 return;
800 }
801
6109c850 802 spin_lock(&ctx->flc_lock);
bd61e0a9
JL
803 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
804 if (posix_locks_conflict(fl, cfl)) {
805 locks_copy_conflock(fl, cfl);
806 if (cfl->fl_nspid)
807 fl->fl_pid = pid_vnr(cfl->fl_nspid);
808 goto out;
809 }
1da177e4 810 }
bd61e0a9
JL
811 fl->fl_type = F_UNLCK;
812out:
6109c850 813 spin_unlock(&ctx->flc_lock);
6d34ac19 814 return;
1da177e4 815}
1da177e4
LT
816EXPORT_SYMBOL(posix_test_lock);
817
b533184f
BF
818/*
819 * Deadlock detection:
820 *
821 * We attempt to detect deadlocks that are due purely to posix file
822 * locks.
1da177e4 823 *
b533184f
BF
824 * We assume that a task can be waiting for at most one lock at a time.
825 * So for any acquired lock, the process holding that lock may be
826 * waiting on at most one other lock. That lock in turns may be held by
827 * someone waiting for at most one other lock. Given a requested lock
828 * caller_fl which is about to wait for a conflicting lock block_fl, we
829 * follow this chain of waiters to ensure we are not about to create a
830 * cycle.
1da177e4 831 *
b533184f
BF
832 * Since we do this before we ever put a process to sleep on a lock, we
833 * are ensured that there is never a cycle; that is what guarantees that
834 * the while() loop in posix_locks_deadlock() eventually completes.
97855b49 835 *
b533184f
BF
836 * Note: the above assumption may not be true when handling lock
837 * requests from a broken NFS client. It may also fail in the presence
838 * of tasks (such as posix threads) sharing the same open file table.
b533184f 839 * To handle those cases, we just bail out after a few iterations.
57b65325 840 *
cff2fce5 841 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
57b65325
JL
842 * Because the owner is not even nominally tied to a thread of
843 * execution, the deadlock detection below can't reasonably work well. Just
844 * skip it for those.
845 *
cff2fce5 846 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
57b65325
JL
847 * locks that just checks for the case where two tasks are attempting to
848 * upgrade from read to write locks on the same inode.
1da177e4 849 */
97855b49
BF
850
851#define MAX_DEADLK_ITERATIONS 10
852
b533184f
BF
853/* Find a lock that the owner of the given block_fl is blocking on. */
854static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
855{
856 struct file_lock *fl;
857
3999e493 858 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
b533184f
BF
859 if (posix_same_owner(fl, block_fl))
860 return fl->fl_next;
861 }
862 return NULL;
863}
864
7b2296af 865/* Must be called with the blocked_lock_lock held! */
b0904e14 866static int posix_locks_deadlock(struct file_lock *caller_fl,
1da177e4
LT
867 struct file_lock *block_fl)
868{
97855b49 869 int i = 0;
1da177e4 870
663d5af7
DW
871 lockdep_assert_held(&blocked_lock_lock);
872
57b65325
JL
873 /*
874 * This deadlock detector can't reasonably detect deadlocks with
cff2fce5 875 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
57b65325 876 */
cff2fce5 877 if (IS_OFDLCK(caller_fl))
57b65325
JL
878 return 0;
879
b533184f
BF
880 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
881 if (i++ > MAX_DEADLK_ITERATIONS)
882 return 0;
883 if (posix_same_owner(caller_fl, block_fl))
884 return 1;
1da177e4
LT
885 }
886 return 0;
887}
888
1da177e4 889/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
02888f41 890 * after any leases, but before any posix locks.
f475ae95
TM
891 *
892 * Note that if called with an FL_EXISTS argument, the caller may determine
893 * whether or not a lock was successfully freed by testing the return
894 * value for -ENOENT.
1da177e4 895 */
bcd7f78d 896static int flock_lock_inode(struct inode *inode, struct file_lock *request)
1da177e4 897{
993dfa87 898 struct file_lock *new_fl = NULL;
5263e31e
JL
899 struct file_lock *fl;
900 struct file_lock_context *ctx;
1da177e4 901 int error = 0;
5263e31e 902 bool found = false;
ed9814d8 903 LIST_HEAD(dispose);
1da177e4 904
5c1c669a
JL
905 ctx = locks_get_lock_context(inode, request->fl_type);
906 if (!ctx) {
907 if (request->fl_type != F_UNLCK)
908 return -ENOMEM;
909 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
910 }
5263e31e 911
b89f4321 912 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
84d535ad 913 new_fl = locks_alloc_lock();
b89f4321
AB
914 if (!new_fl)
915 return -ENOMEM;
84d535ad
PE
916 }
917
6109c850 918 spin_lock(&ctx->flc_lock);
b89f4321
AB
919 if (request->fl_flags & FL_ACCESS)
920 goto find_conflict;
921
5263e31e 922 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
bcd7f78d 923 if (request->fl_file != fl->fl_file)
1da177e4 924 continue;
993dfa87 925 if (request->fl_type == fl->fl_type)
1da177e4 926 goto out;
5263e31e 927 found = true;
e084c1bd 928 locks_delete_lock_ctx(fl, &dispose);
1da177e4
LT
929 break;
930 }
1da177e4 931
f475ae95
TM
932 if (request->fl_type == F_UNLCK) {
933 if ((request->fl_flags & FL_EXISTS) && !found)
934 error = -ENOENT;
993dfa87 935 goto out;
f475ae95 936 }
1da177e4 937
f07f18dd 938find_conflict:
5263e31e 939 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
993dfa87 940 if (!flock_locks_conflict(request, fl))
1da177e4
LT
941 continue;
942 error = -EAGAIN;
bde74e4b
MS
943 if (!(request->fl_flags & FL_SLEEP))
944 goto out;
945 error = FILE_LOCK_DEFERRED;
946 locks_insert_block(fl, request);
1da177e4
LT
947 goto out;
948 }
f07f18dd
TM
949 if (request->fl_flags & FL_ACCESS)
950 goto out;
993dfa87 951 locks_copy_lock(new_fl, request);
e084c1bd 952 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
993dfa87 953 new_fl = NULL;
9cedc194 954 error = 0;
1da177e4
LT
955
956out:
6109c850 957 spin_unlock(&ctx->flc_lock);
993dfa87
TM
958 if (new_fl)
959 locks_free_lock(new_fl);
ed9814d8 960 locks_dispose_list(&dispose);
1da177e4
LT
961 return error;
962}
963
b4d629a3
JL
964static int posix_lock_inode(struct inode *inode, struct file_lock *request,
965 struct file_lock *conflock)
1da177e4 966{
bd61e0a9 967 struct file_lock *fl, *tmp;
39005d02
MS
968 struct file_lock *new_fl = NULL;
969 struct file_lock *new_fl2 = NULL;
1da177e4
LT
970 struct file_lock *left = NULL;
971 struct file_lock *right = NULL;
bd61e0a9 972 struct file_lock_context *ctx;
b9746ef8
JL
973 int error;
974 bool added = false;
ed9814d8 975 LIST_HEAD(dispose);
1da177e4 976
5c1c669a 977 ctx = locks_get_lock_context(inode, request->fl_type);
bd61e0a9 978 if (!ctx)
5c1c669a 979 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
bd61e0a9 980
1da177e4
LT
981 /*
982 * We may need two file_lock structures for this operation,
983 * so we get them in advance to avoid races.
39005d02
MS
984 *
985 * In some cases we can be sure, that no new locks will be needed
1da177e4 986 */
39005d02
MS
987 if (!(request->fl_flags & FL_ACCESS) &&
988 (request->fl_type != F_UNLCK ||
989 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
990 new_fl = locks_alloc_lock();
991 new_fl2 = locks_alloc_lock();
992 }
1da177e4 993
6109c850 994 spin_lock(&ctx->flc_lock);
1cb36012
JL
995 /*
996 * New lock request. Walk all POSIX locks and look for conflicts. If
997 * there are any, either return error or put the request on the
48f74186 998 * blocker's list of waiters and the global blocked_hash.
1cb36012 999 */
1da177e4 1000 if (request->fl_type != F_UNLCK) {
bd61e0a9 1001 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1da177e4
LT
1002 if (!posix_locks_conflict(request, fl))
1003 continue;
5842add2 1004 if (conflock)
3fe0fff1 1005 locks_copy_conflock(conflock, fl);
1da177e4
LT
1006 error = -EAGAIN;
1007 if (!(request->fl_flags & FL_SLEEP))
1008 goto out;
1c8c601a
JL
1009 /*
1010 * Deadlock detection and insertion into the blocked
1011 * locks list must be done while holding the same lock!
1012 */
1da177e4 1013 error = -EDEADLK;
7b2296af 1014 spin_lock(&blocked_lock_lock);
1c8c601a
JL
1015 if (likely(!posix_locks_deadlock(request, fl))) {
1016 error = FILE_LOCK_DEFERRED;
1017 __locks_insert_block(fl, request);
1018 }
7b2296af 1019 spin_unlock(&blocked_lock_lock);
1da177e4
LT
1020 goto out;
1021 }
1022 }
1023
1024 /* If we're just looking for a conflict, we're done. */
1025 error = 0;
1026 if (request->fl_flags & FL_ACCESS)
1027 goto out;
1028
bd61e0a9
JL
1029 /* Find the first old lock with the same owner as the new lock */
1030 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1031 if (posix_same_owner(request, fl))
1032 break;
1da177e4
LT
1033 }
1034
1cb36012 1035 /* Process locks with this owner. */
bd61e0a9
JL
1036 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1037 if (!posix_same_owner(request, fl))
1038 break;
1039
1040 /* Detect adjacent or overlapping regions (if same lock type) */
1da177e4 1041 if (request->fl_type == fl->fl_type) {
449231d6
OK
1042 /* In all comparisons of start vs end, use
1043 * "start - 1" rather than "end + 1". If end
1044 * is OFFSET_MAX, end + 1 will become negative.
1045 */
1da177e4 1046 if (fl->fl_end < request->fl_start - 1)
bd61e0a9 1047 continue;
1da177e4
LT
1048 /* If the next lock in the list has entirely bigger
1049 * addresses than the new one, insert the lock here.
1050 */
449231d6 1051 if (fl->fl_start - 1 > request->fl_end)
1da177e4
LT
1052 break;
1053
1054 /* If we come here, the new and old lock are of the
1055 * same type and adjacent or overlapping. Make one
1056 * lock yielding from the lower start address of both
1057 * locks to the higher end address.
1058 */
1059 if (fl->fl_start > request->fl_start)
1060 fl->fl_start = request->fl_start;
1061 else
1062 request->fl_start = fl->fl_start;
1063 if (fl->fl_end < request->fl_end)
1064 fl->fl_end = request->fl_end;
1065 else
1066 request->fl_end = fl->fl_end;
1067 if (added) {
e084c1bd 1068 locks_delete_lock_ctx(fl, &dispose);
1da177e4
LT
1069 continue;
1070 }
1071 request = fl;
b9746ef8 1072 added = true;
bd61e0a9 1073 } else {
1da177e4
LT
1074 /* Processing for different lock types is a bit
1075 * more complex.
1076 */
1077 if (fl->fl_end < request->fl_start)
bd61e0a9 1078 continue;
1da177e4
LT
1079 if (fl->fl_start > request->fl_end)
1080 break;
1081 if (request->fl_type == F_UNLCK)
b9746ef8 1082 added = true;
1da177e4
LT
1083 if (fl->fl_start < request->fl_start)
1084 left = fl;
1085 /* If the next lock in the list has a higher end
1086 * address than the new one, insert the new one here.
1087 */
1088 if (fl->fl_end > request->fl_end) {
1089 right = fl;
1090 break;
1091 }
1092 if (fl->fl_start >= request->fl_start) {
1093 /* The new lock completely replaces an old
1094 * one (This may happen several times).
1095 */
1096 if (added) {
e084c1bd 1097 locks_delete_lock_ctx(fl, &dispose);
1da177e4
LT
1098 continue;
1099 }
b84d49f9
JL
1100 /*
1101 * Replace the old lock with new_fl, and
1102 * remove the old one. It's safe to do the
1103 * insert here since we know that we won't be
1104 * using new_fl later, and that the lock is
1105 * just replacing an existing lock.
1da177e4 1106 */
b84d49f9
JL
1107 error = -ENOLCK;
1108 if (!new_fl)
1109 goto out;
1110 locks_copy_lock(new_fl, request);
1111 request = new_fl;
1112 new_fl = NULL;
e084c1bd
JL
1113 locks_insert_lock_ctx(request, &fl->fl_list);
1114 locks_delete_lock_ctx(fl, &dispose);
b9746ef8 1115 added = true;
1da177e4
LT
1116 }
1117 }
1da177e4
LT
1118 }
1119
0d9a490a 1120 /*
1cb36012
JL
1121 * The above code only modifies existing locks in case of merging or
1122 * replacing. If new lock(s) need to be inserted all modifications are
1123 * done below this, so it's safe yet to bail out.
0d9a490a
MS
1124 */
1125 error = -ENOLCK; /* "no luck" */
1126 if (right && left == right && !new_fl2)
1127 goto out;
1128
1da177e4
LT
1129 error = 0;
1130 if (!added) {
f475ae95
TM
1131 if (request->fl_type == F_UNLCK) {
1132 if (request->fl_flags & FL_EXISTS)
1133 error = -ENOENT;
1da177e4 1134 goto out;
f475ae95 1135 }
0d9a490a
MS
1136
1137 if (!new_fl) {
1138 error = -ENOLCK;
1139 goto out;
1140 }
1da177e4 1141 locks_copy_lock(new_fl, request);
e084c1bd 1142 locks_insert_lock_ctx(new_fl, &fl->fl_list);
2e2f756f 1143 fl = new_fl;
1da177e4
LT
1144 new_fl = NULL;
1145 }
1146 if (right) {
1147 if (left == right) {
1148 /* The new lock breaks the old one in two pieces,
1149 * so we have to use the second new lock.
1150 */
1151 left = new_fl2;
1152 new_fl2 = NULL;
1153 locks_copy_lock(left, right);
e084c1bd 1154 locks_insert_lock_ctx(left, &fl->fl_list);
1da177e4
LT
1155 }
1156 right->fl_start = request->fl_end + 1;
1157 locks_wake_up_blocks(right);
1158 }
1159 if (left) {
1160 left->fl_end = request->fl_start - 1;
1161 locks_wake_up_blocks(left);
1162 }
1163 out:
6109c850 1164 spin_unlock(&ctx->flc_lock);
1da177e4
LT
1165 /*
1166 * Free any unused locks.
1167 */
1168 if (new_fl)
1169 locks_free_lock(new_fl);
1170 if (new_fl2)
1171 locks_free_lock(new_fl2);
ed9814d8 1172 locks_dispose_list(&dispose);
1890910f
JL
1173 trace_posix_lock_inode(inode, request, error);
1174
1da177e4
LT
1175 return error;
1176}
1177
1178/**
1179 * posix_lock_file - Apply a POSIX-style lock to a file
1180 * @filp: The file to apply the lock to
1181 * @fl: The lock to be applied
150b3934 1182 * @conflock: Place to return a copy of the conflicting lock, if found.
1da177e4
LT
1183 *
1184 * Add a POSIX style lock to a file.
1185 * We merge adjacent & overlapping locks whenever possible.
1186 * POSIX locks are sorted by owner task, then by starting address
f475ae95
TM
1187 *
1188 * Note that if called with an FL_EXISTS argument, the caller may determine
1189 * whether or not a lock was successfully freed by testing the return
1190 * value for -ENOENT.
1da177e4 1191 */
150b3934 1192int posix_lock_file(struct file *filp, struct file_lock *fl,
5842add2
AA
1193 struct file_lock *conflock)
1194{
b4d629a3 1195 return posix_lock_inode(file_inode(filp), fl, conflock);
1da177e4 1196}
150b3934 1197EXPORT_SYMBOL(posix_lock_file);
1da177e4
LT
1198
1199/**
29d01b22
JL
1200 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1201 * @inode: inode of file to which lock request should be applied
1da177e4
LT
1202 * @fl: The lock to be applied
1203 *
616fb38f 1204 * Apply a POSIX style lock request to an inode.
1da177e4 1205 */
616fb38f 1206static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1da177e4
LT
1207{
1208 int error;
1209 might_sleep ();
1210 for (;;) {
b4d629a3 1211 error = posix_lock_inode(inode, fl, NULL);
bde74e4b 1212 if (error != FILE_LOCK_DEFERRED)
1da177e4
LT
1213 break;
1214 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1215 if (!error)
1216 continue;
1217
1218 locks_delete_block(fl);
1219 break;
1220 }
1221 return error;
1222}
29d01b22 1223
9e8925b6 1224#ifdef CONFIG_MANDATORY_FILE_LOCKING
1da177e4
LT
1225/**
1226 * locks_mandatory_locked - Check for an active lock
d7a06983 1227 * @file: the file to check
1da177e4
LT
1228 *
1229 * Searches the inode's list of locks to find any POSIX locks which conflict.
1230 * This function is called from locks_verify_locked() only.
1231 */
d7a06983 1232int locks_mandatory_locked(struct file *file)
1da177e4 1233{
bd61e0a9 1234 int ret;
d7a06983 1235 struct inode *inode = file_inode(file);
bd61e0a9 1236 struct file_lock_context *ctx;
1da177e4
LT
1237 struct file_lock *fl;
1238
128a3785 1239 ctx = smp_load_acquire(&inode->i_flctx);
bd61e0a9
JL
1240 if (!ctx || list_empty_careful(&ctx->flc_posix))
1241 return 0;
1242
1da177e4
LT
1243 /*
1244 * Search the lock list for this inode for any POSIX locks.
1245 */
6109c850 1246 spin_lock(&ctx->flc_lock);
bd61e0a9
JL
1247 ret = 0;
1248 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
73a8f5f7 1249 if (fl->fl_owner != current->files &&
bd61e0a9
JL
1250 fl->fl_owner != file) {
1251 ret = -EAGAIN;
1da177e4 1252 break;
bd61e0a9 1253 }
1da177e4 1254 }
6109c850 1255 spin_unlock(&ctx->flc_lock);
bd61e0a9 1256 return ret;
1da177e4
LT
1257}
1258
1259/**
1260 * locks_mandatory_area - Check for a conflicting lock
acc15575 1261 * @inode: the file to check
1da177e4 1262 * @filp: how the file was opened (if it was)
acc15575
CH
1263 * @start: first byte in the file to check
1264 * @end: lastbyte in the file to check
1265 * @type: %F_WRLCK for a write lock, else %F_RDLCK
1da177e4
LT
1266 *
1267 * Searches the inode's list of locks to find any POSIX locks which conflict.
1da177e4 1268 */
acc15575
CH
1269int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1270 loff_t end, unsigned char type)
1da177e4
LT
1271{
1272 struct file_lock fl;
1273 int error;
29723ade 1274 bool sleep = false;
1da177e4
LT
1275
1276 locks_init_lock(&fl);
1da177e4
LT
1277 fl.fl_pid = current->tgid;
1278 fl.fl_file = filp;
1279 fl.fl_flags = FL_POSIX | FL_ACCESS;
1280 if (filp && !(filp->f_flags & O_NONBLOCK))
29723ade 1281 sleep = true;
acc15575
CH
1282 fl.fl_type = type;
1283 fl.fl_start = start;
1284 fl.fl_end = end;
1da177e4
LT
1285
1286 for (;;) {
29723ade 1287 if (filp) {
73a8f5f7 1288 fl.fl_owner = filp;
29723ade 1289 fl.fl_flags &= ~FL_SLEEP;
b4d629a3 1290 error = posix_lock_inode(inode, &fl, NULL);
29723ade
JL
1291 if (!error)
1292 break;
1293 }
1294
1295 if (sleep)
1296 fl.fl_flags |= FL_SLEEP;
1297 fl.fl_owner = current->files;
b4d629a3 1298 error = posix_lock_inode(inode, &fl, NULL);
bde74e4b 1299 if (error != FILE_LOCK_DEFERRED)
1da177e4
LT
1300 break;
1301 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1302 if (!error) {
1303 /*
1304 * If we've been sleeping someone might have
1305 * changed the permissions behind our back.
1306 */
a16877ca 1307 if (__mandatory_lock(inode))
1da177e4
LT
1308 continue;
1309 }
1310
1311 locks_delete_block(&fl);
1312 break;
1313 }
1314
1315 return error;
1316}
1317
1318EXPORT_SYMBOL(locks_mandatory_area);
9e8925b6 1319#endif /* CONFIG_MANDATORY_FILE_LOCKING */
1da177e4 1320
778fc546
BF
1321static void lease_clear_pending(struct file_lock *fl, int arg)
1322{
1323 switch (arg) {
1324 case F_UNLCK:
1325 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1326 /* fall through: */
1327 case F_RDLCK:
1328 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1329 }
1330}
1331
1da177e4 1332/* We already had a lease on this file; just change its type */
7448cc37 1333int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
1da177e4 1334{
1da177e4
LT
1335 int error = assign_type(fl, arg);
1336
1337 if (error)
1338 return error;
778fc546 1339 lease_clear_pending(fl, arg);
1da177e4 1340 locks_wake_up_blocks(fl);
3b6e2723
FB
1341 if (arg == F_UNLCK) {
1342 struct file *filp = fl->fl_file;
1343
1344 f_delown(filp);
1345 filp->f_owner.signum = 0;
96d6d59c
BF
1346 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1347 if (fl->fl_fasync != NULL) {
1348 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1349 fl->fl_fasync = NULL;
1350 }
e084c1bd 1351 locks_delete_lock_ctx(fl, dispose);
3b6e2723 1352 }
1da177e4
LT
1353 return 0;
1354}
1da177e4
LT
1355EXPORT_SYMBOL(lease_modify);
1356
778fc546
BF
1357static bool past_time(unsigned long then)
1358{
1359 if (!then)
1360 /* 0 is a special value meaning "this never expires": */
1361 return false;
1362 return time_after(jiffies, then);
1363}
1364
c45198ed 1365static void time_out_leases(struct inode *inode, struct list_head *dispose)
1da177e4 1366{
8634b51f
JL
1367 struct file_lock_context *ctx = inode->i_flctx;
1368 struct file_lock *fl, *tmp;
1da177e4 1369
6109c850 1370 lockdep_assert_held(&ctx->flc_lock);
f82b4b67 1371
8634b51f 1372 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
62af4f1f 1373 trace_time_out_leases(inode, fl);
778fc546 1374 if (past_time(fl->fl_downgrade_time))
7448cc37 1375 lease_modify(fl, F_RDLCK, dispose);
778fc546 1376 if (past_time(fl->fl_break_time))
7448cc37 1377 lease_modify(fl, F_UNLCK, dispose);
1da177e4
LT
1378 }
1379}
1380
df4e8d2c
BF
1381static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1382{
11afe9f7
CH
1383 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1384 return false;
df4e8d2c
BF
1385 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1386 return false;
1387 return locks_conflict(breaker, lease);
1388}
1389
03d12ddf
JL
1390static bool
1391any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1392{
8634b51f 1393 struct file_lock_context *ctx = inode->i_flctx;
03d12ddf
JL
1394 struct file_lock *fl;
1395
6109c850 1396 lockdep_assert_held(&ctx->flc_lock);
03d12ddf 1397
8634b51f 1398 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
03d12ddf
JL
1399 if (leases_conflict(fl, breaker))
1400 return true;
1401 }
1402 return false;
1403}
1404
1da177e4
LT
1405/**
1406 * __break_lease - revoke all outstanding leases on file
1407 * @inode: the inode of the file to return
df4e8d2c
BF
1408 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1409 * break all leases
1410 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1411 * only delegations
1da177e4 1412 *
87250dd2 1413 * break_lease (inlined for speed) has checked there already is at least
1414 * some kind of lock (maybe a lease) on this file. Leases are broken on
1415 * a call to open() or truncate(). This function can sleep unless you
1da177e4
LT
1416 * specified %O_NONBLOCK to your open().
1417 */
df4e8d2c 1418int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1da177e4 1419{
778fc546 1420 int error = 0;
128a3785 1421 struct file_lock_context *ctx;
a901125c 1422 struct file_lock *new_fl, *fl, *tmp;
1da177e4 1423 unsigned long break_time;
8737c930 1424 int want_write = (mode & O_ACCMODE) != O_RDONLY;
c45198ed 1425 LIST_HEAD(dispose);
1da177e4 1426
8737c930 1427 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
6d4b9e38
LT
1428 if (IS_ERR(new_fl))
1429 return PTR_ERR(new_fl);
df4e8d2c 1430 new_fl->fl_flags = type;
1da177e4 1431
8634b51f 1432 /* typically we will check that ctx is non-NULL before calling */
128a3785 1433 ctx = smp_load_acquire(&inode->i_flctx);
8634b51f
JL
1434 if (!ctx) {
1435 WARN_ON_ONCE(1);
1436 return error;
1437 }
1438
6109c850 1439 spin_lock(&ctx->flc_lock);
1da177e4 1440
c45198ed 1441 time_out_leases(inode, &dispose);
1da177e4 1442
03d12ddf 1443 if (!any_leases_conflict(inode, new_fl))
778fc546
BF
1444 goto out;
1445
1da177e4
LT
1446 break_time = 0;
1447 if (lease_break_time > 0) {
1448 break_time = jiffies + lease_break_time * HZ;
1449 if (break_time == 0)
1450 break_time++; /* so that 0 means no break time */
1451 }
1452
a901125c 1453 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
df4e8d2c
BF
1454 if (!leases_conflict(fl, new_fl))
1455 continue;
778fc546
BF
1456 if (want_write) {
1457 if (fl->fl_flags & FL_UNLOCK_PENDING)
1458 continue;
1459 fl->fl_flags |= FL_UNLOCK_PENDING;
1da177e4 1460 fl->fl_break_time = break_time;
778fc546 1461 } else {
8634b51f 1462 if (lease_breaking(fl))
778fc546
BF
1463 continue;
1464 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1465 fl->fl_downgrade_time = break_time;
1da177e4 1466 }
4d01b7f5 1467 if (fl->fl_lmops->lm_break(fl))
e084c1bd 1468 locks_delete_lock_ctx(fl, &dispose);
1da177e4
LT
1469 }
1470
8634b51f 1471 if (list_empty(&ctx->flc_lease))
4d01b7f5
JL
1472 goto out;
1473
843c6b2f 1474 if (mode & O_NONBLOCK) {
62af4f1f 1475 trace_break_lease_noblock(inode, new_fl);
1da177e4
LT
1476 error = -EWOULDBLOCK;
1477 goto out;
1478 }
1479
1480restart:
8634b51f
JL
1481 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1482 break_time = fl->fl_break_time;
f1c6bb2c 1483 if (break_time != 0)
1da177e4 1484 break_time -= jiffies;
f1c6bb2c
JL
1485 if (break_time == 0)
1486 break_time++;
8634b51f 1487 locks_insert_block(fl, new_fl);
62af4f1f 1488 trace_break_lease_block(inode, new_fl);
6109c850 1489 spin_unlock(&ctx->flc_lock);
c45198ed 1490 locks_dispose_list(&dispose);
4321e01e
MW
1491 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1492 !new_fl->fl_next, break_time);
6109c850 1493 spin_lock(&ctx->flc_lock);
62af4f1f 1494 trace_break_lease_unblock(inode, new_fl);
1c8c601a 1495 locks_delete_block(new_fl);
1da177e4 1496 if (error >= 0) {
778fc546
BF
1497 /*
1498 * Wait for the next conflicting lease that has not been
1499 * broken yet
1500 */
03d12ddf
JL
1501 if (error == 0)
1502 time_out_leases(inode, &dispose);
1503 if (any_leases_conflict(inode, new_fl))
1504 goto restart;
1da177e4
LT
1505 error = 0;
1506 }
1da177e4 1507out:
6109c850 1508 spin_unlock(&ctx->flc_lock);
c45198ed 1509 locks_dispose_list(&dispose);
6d4b9e38 1510 locks_free_lock(new_fl);
1da177e4
LT
1511 return error;
1512}
1513
1514EXPORT_SYMBOL(__break_lease);
1515
1516/**
a6b91919 1517 * lease_get_mtime - get the last modified time of an inode
1da177e4
LT
1518 * @inode: the inode
1519 * @time: pointer to a timespec which will contain the last modified time
1520 *
1521 * This is to force NFS clients to flush their caches for files with
1522 * exclusive leases. The justification is that if someone has an
a6b91919 1523 * exclusive lease, then they could be modifying it.
1da177e4
LT
1524 */
1525void lease_get_mtime(struct inode *inode, struct timespec *time)
1526{
bfe86024 1527 bool has_lease = false;
128a3785 1528 struct file_lock_context *ctx;
8634b51f 1529 struct file_lock *fl;
bfe86024 1530
128a3785 1531 ctx = smp_load_acquire(&inode->i_flctx);
8634b51f 1532 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
6109c850 1533 spin_lock(&ctx->flc_lock);
8ace5dfb
GT
1534 fl = list_first_entry_or_null(&ctx->flc_lease,
1535 struct file_lock, fl_list);
1536 if (fl && (fl->fl_type == F_WRLCK))
1537 has_lease = true;
6109c850 1538 spin_unlock(&ctx->flc_lock);
bfe86024
JL
1539 }
1540
1541 if (has_lease)
1da177e4
LT
1542 *time = current_fs_time(inode->i_sb);
1543 else
1544 *time = inode->i_mtime;
1545}
1546
1547EXPORT_SYMBOL(lease_get_mtime);
1548
1549/**
1550 * fcntl_getlease - Enquire what lease is currently active
1551 * @filp: the file
1552 *
1553 * The value returned by this function will be one of
1554 * (if no lease break is pending):
1555 *
1556 * %F_RDLCK to indicate a shared lease is held.
1557 *
1558 * %F_WRLCK to indicate an exclusive lease is held.
1559 *
1560 * %F_UNLCK to indicate no lease is held.
1561 *
1562 * (if a lease break is pending):
1563 *
1564 * %F_RDLCK to indicate an exclusive lease needs to be
1565 * changed to a shared lease (or removed).
1566 *
1567 * %F_UNLCK to indicate the lease needs to be removed.
1568 *
1569 * XXX: sfr & willy disagree over whether F_INPROGRESS
1570 * should be returned to userspace.
1571 */
1572int fcntl_getlease(struct file *filp)
1573{
1574 struct file_lock *fl;
1c8c601a 1575 struct inode *inode = file_inode(filp);
128a3785 1576 struct file_lock_context *ctx;
1da177e4 1577 int type = F_UNLCK;
c45198ed 1578 LIST_HEAD(dispose);
1da177e4 1579
128a3785 1580 ctx = smp_load_acquire(&inode->i_flctx);
8634b51f 1581 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
6109c850 1582 spin_lock(&ctx->flc_lock);
8634b51f
JL
1583 time_out_leases(file_inode(filp), &dispose);
1584 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1585 if (fl->fl_file != filp)
1586 continue;
778fc546 1587 type = target_leasetype(fl);
1da177e4
LT
1588 break;
1589 }
6109c850 1590 spin_unlock(&ctx->flc_lock);
8634b51f 1591 locks_dispose_list(&dispose);
1da177e4 1592 }
1da177e4
LT
1593 return type;
1594}
1595
24cbe784
JL
1596/**
1597 * check_conflicting_open - see if the given dentry points to a file that has
1598 * an existing open that would conflict with the
1599 * desired lease.
1600 * @dentry: dentry to check
1601 * @arg: type of lease that we're trying to acquire
7fadc59c 1602 * @flags: current lock flags
24cbe784
JL
1603 *
1604 * Check to see if there's an existing open fd on this file that would
1605 * conflict with the lease we're trying to set.
1606 */
1607static int
11afe9f7 1608check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
24cbe784
JL
1609{
1610 int ret = 0;
1611 struct inode *inode = dentry->d_inode;
1612
11afe9f7
CH
1613 if (flags & FL_LAYOUT)
1614 return 0;
1615
24cbe784
JL
1616 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1617 return -EAGAIN;
1618
1619 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1620 (atomic_read(&inode->i_count) > 1)))
1621 ret = -EAGAIN;
1622
1623 return ret;
1624}
1625
e6f5c789
JL
1626static int
1627generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1da177e4 1628{
8634b51f 1629 struct file_lock *fl, *my_fl = NULL, *lease;
0f7fc9e4 1630 struct dentry *dentry = filp->f_path.dentry;
1da177e4 1631 struct inode *inode = dentry->d_inode;
8634b51f 1632 struct file_lock_context *ctx;
df4e8d2c 1633 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
c1f24ef4 1634 int error;
c45198ed 1635 LIST_HEAD(dispose);
1da177e4 1636
096657b6 1637 lease = *flp;
62af4f1f
JL
1638 trace_generic_add_lease(inode, lease);
1639
5c1c669a
JL
1640 /* Note that arg is never F_UNLCK here */
1641 ctx = locks_get_lock_context(inode, arg);
8634b51f
JL
1642 if (!ctx)
1643 return -ENOMEM;
1644
df4e8d2c
BF
1645 /*
1646 * In the delegation case we need mutual exclusion with
1647 * a number of operations that take the i_mutex. We trylock
1648 * because delegations are an optional optimization, and if
1649 * there's some chance of a conflict--we'd rather not
1650 * bother, maybe that's a sign this just isn't a good file to
1651 * hand out a delegation on.
1652 */
5955102c 1653 if (is_deleg && !inode_trylock(inode))
df4e8d2c
BF
1654 return -EAGAIN;
1655
1656 if (is_deleg && arg == F_WRLCK) {
1657 /* Write delegations are not currently supported: */
5955102c 1658 inode_unlock(inode);
df4e8d2c
BF
1659 WARN_ON_ONCE(1);
1660 return -EINVAL;
1661 }
096657b6 1662
6109c850 1663 spin_lock(&ctx->flc_lock);
c45198ed 1664 time_out_leases(inode, &dispose);
11afe9f7 1665 error = check_conflicting_open(dentry, arg, lease->fl_flags);
24cbe784 1666 if (error)
096657b6 1667 goto out;
6d5e8b05 1668
1da177e4
LT
1669 /*
1670 * At this point, we know that if there is an exclusive
1671 * lease on this file, then we hold it on this filp
1672 * (otherwise our open of this file would have blocked).
1673 * And if we are trying to acquire an exclusive lease,
1674 * then the file is not open by anyone (including us)
1675 * except for this filp.
1676 */
c1f24ef4 1677 error = -EAGAIN;
8634b51f 1678 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
2ab99ee1
CH
1679 if (fl->fl_file == filp &&
1680 fl->fl_owner == lease->fl_owner) {
8634b51f 1681 my_fl = fl;
c1f24ef4
BF
1682 continue;
1683 }
8634b51f 1684
c1f24ef4
BF
1685 /*
1686 * No exclusive leases if someone else has a lease on
1687 * this file:
1688 */
1689 if (arg == F_WRLCK)
1690 goto out;
1691 /*
1692 * Modifying our existing lease is OK, but no getting a
1693 * new lease if someone else is opening for write:
1694 */
1695 if (fl->fl_flags & FL_UNLOCK_PENDING)
1696 goto out;
1da177e4
LT
1697 }
1698
8634b51f 1699 if (my_fl != NULL) {
0164bf02
JL
1700 lease = my_fl;
1701 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
1c7dd2ff
JL
1702 if (error)
1703 goto out;
1704 goto out_setup;
1da177e4
LT
1705 }
1706
1da177e4
LT
1707 error = -EINVAL;
1708 if (!leases_enable)
1709 goto out;
1710
e084c1bd 1711 locks_insert_lock_ctx(lease, &ctx->flc_lease);
24cbe784
JL
1712 /*
1713 * The check in break_lease() is lockless. It's possible for another
1714 * open to race in after we did the earlier check for a conflicting
1715 * open but before the lease was inserted. Check again for a
1716 * conflicting open and cancel the lease if there is one.
1717 *
1718 * We also add a barrier here to ensure that the insertion of the lock
1719 * precedes these checks.
1720 */
1721 smp_mb();
11afe9f7 1722 error = check_conflicting_open(dentry, arg, lease->fl_flags);
8634b51f 1723 if (error) {
e084c1bd 1724 locks_unlink_lock_ctx(lease);
8634b51f
JL
1725 goto out;
1726 }
1c7dd2ff
JL
1727
1728out_setup:
1729 if (lease->fl_lmops->lm_setup)
1730 lease->fl_lmops->lm_setup(lease, priv);
1da177e4 1731out:
6109c850 1732 spin_unlock(&ctx->flc_lock);
c45198ed 1733 locks_dispose_list(&dispose);
df4e8d2c 1734 if (is_deleg)
5955102c 1735 inode_unlock(inode);
8634b51f 1736 if (!error && !my_fl)
1c7dd2ff 1737 *flp = NULL;
1da177e4
LT
1738 return error;
1739}
8335ebd9 1740
2ab99ee1 1741static int generic_delete_lease(struct file *filp, void *owner)
8335ebd9 1742{
0efaa7e8 1743 int error = -EAGAIN;
8634b51f 1744 struct file_lock *fl, *victim = NULL;
6ca7d910 1745 struct inode *inode = file_inode(filp);
128a3785 1746 struct file_lock_context *ctx;
c45198ed 1747 LIST_HEAD(dispose);
8335ebd9 1748
128a3785 1749 ctx = smp_load_acquire(&inode->i_flctx);
8634b51f
JL
1750 if (!ctx) {
1751 trace_generic_delete_lease(inode, NULL);
1752 return error;
1753 }
1754
6109c850 1755 spin_lock(&ctx->flc_lock);
8634b51f 1756 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
2ab99ee1
CH
1757 if (fl->fl_file == filp &&
1758 fl->fl_owner == owner) {
8634b51f 1759 victim = fl;
0efaa7e8 1760 break;
8634b51f 1761 }
8335ebd9 1762 }
a9b1b455 1763 trace_generic_delete_lease(inode, victim);
8634b51f 1764 if (victim)
7448cc37 1765 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
6109c850 1766 spin_unlock(&ctx->flc_lock);
c45198ed 1767 locks_dispose_list(&dispose);
0efaa7e8 1768 return error;
8335ebd9
BF
1769}
1770
1771/**
1772 * generic_setlease - sets a lease on an open file
1c7dd2ff
JL
1773 * @filp: file pointer
1774 * @arg: type of lease to obtain
1775 * @flp: input - file_lock to use, output - file_lock inserted
1776 * @priv: private data for lm_setup (may be NULL if lm_setup
1777 * doesn't require it)
8335ebd9
BF
1778 *
1779 * The (input) flp->fl_lmops->lm_break function is required
1780 * by break_lease().
8335ebd9 1781 */
e6f5c789
JL
1782int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1783 void **priv)
8335ebd9 1784{
6ca7d910 1785 struct inode *inode = file_inode(filp);
8335ebd9
BF
1786 int error;
1787
8e96e3b7 1788 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
8335ebd9
BF
1789 return -EACCES;
1790 if (!S_ISREG(inode->i_mode))
1791 return -EINVAL;
1792 error = security_file_lock(filp, arg);
1793 if (error)
1794 return error;
1795
8335ebd9
BF
1796 switch (arg) {
1797 case F_UNLCK:
2ab99ee1 1798 return generic_delete_lease(filp, *priv);
8335ebd9
BF
1799 case F_RDLCK:
1800 case F_WRLCK:
0efaa7e8
JL
1801 if (!(*flp)->fl_lmops->lm_break) {
1802 WARN_ON_ONCE(1);
1803 return -ENOLCK;
1804 }
11afe9f7 1805
e6f5c789 1806 return generic_add_lease(filp, arg, flp, priv);
8335ebd9 1807 default:
8d657eb3 1808 return -EINVAL;
8335ebd9
BF
1809 }
1810}
0af1a450 1811EXPORT_SYMBOL(generic_setlease);
1da177e4 1812
b89f4321 1813/**
e51673aa 1814 * vfs_setlease - sets a lease on an open file
1c7dd2ff
JL
1815 * @filp: file pointer
1816 * @arg: type of lease to obtain
1817 * @lease: file_lock to use when adding a lease
1818 * @priv: private info for lm_setup when adding a lease (may be
1819 * NULL if lm_setup doesn't require it)
e51673aa
JL
1820 *
1821 * Call this to establish a lease on the file. The "lease" argument is not
1822 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1823 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1824 * if not, this function will return -ENOLCK (and generate a scary-looking
1825 * stack trace).
1c7dd2ff
JL
1826 *
1827 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1828 * may be NULL if the lm_setup operation doesn't require it.
1da177e4 1829 */
e6f5c789
JL
1830int
1831vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
1da177e4 1832{
1c7dd2ff 1833 if (filp->f_op->setlease)
f82b4b67 1834 return filp->f_op->setlease(filp, arg, lease, priv);
1c7dd2ff 1835 else
f82b4b67 1836 return generic_setlease(filp, arg, lease, priv);
1da177e4 1837}
a9933cea 1838EXPORT_SYMBOL_GPL(vfs_setlease);
1da177e4 1839
0ceaf6c7 1840static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
1da177e4 1841{
1c7dd2ff 1842 struct file_lock *fl;
f7347ce4 1843 struct fasync_struct *new;
1da177e4
LT
1844 int error;
1845
c5b1f0d9
AB
1846 fl = lease_alloc(filp, arg);
1847 if (IS_ERR(fl))
1848 return PTR_ERR(fl);
1da177e4 1849
f7347ce4
LT
1850 new = fasync_alloc();
1851 if (!new) {
1852 locks_free_lock(fl);
1853 return -ENOMEM;
1854 }
1c7dd2ff 1855 new->fa_fd = fd;
f7347ce4 1856
1c7dd2ff 1857 error = vfs_setlease(filp, arg, &fl, (void **)&new);
2dfb928f
JL
1858 if (fl)
1859 locks_free_lock(fl);
f7347ce4
LT
1860 if (new)
1861 fasync_free(new);
1da177e4
LT
1862 return error;
1863}
1864
0ceaf6c7
BF
1865/**
1866 * fcntl_setlease - sets a lease on an open file
1867 * @fd: open file descriptor
1868 * @filp: file pointer
1869 * @arg: type of lease to obtain
1870 *
1871 * Call this fcntl to establish a lease on the file.
1872 * Note that you also need to call %F_SETSIG to
1873 * receive a signal when the lease is broken.
1874 */
1875int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1876{
1877 if (arg == F_UNLCK)
2ab99ee1 1878 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
0ceaf6c7
BF
1879 return do_fcntl_add_lease(fd, filp, arg);
1880}
1881
1da177e4 1882/**
29d01b22
JL
1883 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1884 * @inode: inode of the file to apply to
1da177e4
LT
1885 * @fl: The lock to be applied
1886 *
29d01b22 1887 * Apply a FLOCK style lock request to an inode.
1da177e4 1888 */
616fb38f 1889static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1da177e4
LT
1890{
1891 int error;
1892 might_sleep();
1893 for (;;) {
29d01b22 1894 error = flock_lock_inode(inode, fl);
bde74e4b 1895 if (error != FILE_LOCK_DEFERRED)
1da177e4
LT
1896 break;
1897 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1898 if (!error)
1899 continue;
1900
1901 locks_delete_block(fl);
1902 break;
1903 }
1904 return error;
1905}
1906
e55c34a6
BC
1907/**
1908 * locks_lock_inode_wait - Apply a lock to an inode
1909 * @inode: inode of the file to apply to
1910 * @fl: The lock to be applied
1911 *
1912 * Apply a POSIX or FLOCK style lock request to an inode.
1913 */
1914int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1915{
1916 int res = 0;
1917 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1918 case FL_POSIX:
1919 res = posix_lock_inode_wait(inode, fl);
1920 break;
1921 case FL_FLOCK:
1922 res = flock_lock_inode_wait(inode, fl);
1923 break;
1924 default:
1925 BUG();
1926 }
1927 return res;
1928}
1929EXPORT_SYMBOL(locks_lock_inode_wait);
1930
1da177e4
LT
1931/**
1932 * sys_flock: - flock() system call.
1933 * @fd: the file descriptor to lock.
1934 * @cmd: the type of lock to apply.
1935 *
1936 * Apply a %FL_FLOCK style lock to an open file descriptor.
1937 * The @cmd can be one of
1938 *
1939 * %LOCK_SH -- a shared lock.
1940 *
1941 * %LOCK_EX -- an exclusive lock.
1942 *
1943 * %LOCK_UN -- remove an existing lock.
1944 *
1945 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1946 *
1947 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1948 * processes read and write access respectively.
1949 */
002c8976 1950SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
1da177e4 1951{
2903ff01 1952 struct fd f = fdget(fd);
1da177e4
LT
1953 struct file_lock *lock;
1954 int can_sleep, unlock;
1955 int error;
1956
1957 error = -EBADF;
2903ff01 1958 if (!f.file)
1da177e4
LT
1959 goto out;
1960
1961 can_sleep = !(cmd & LOCK_NB);
1962 cmd &= ~LOCK_NB;
1963 unlock = (cmd == LOCK_UN);
1964
aeb5d727 1965 if (!unlock && !(cmd & LOCK_MAND) &&
2903ff01 1966 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
1da177e4
LT
1967 goto out_putf;
1968
6e129d00
JL
1969 lock = flock_make_lock(f.file, cmd);
1970 if (IS_ERR(lock)) {
1971 error = PTR_ERR(lock);
1da177e4 1972 goto out_putf;
6e129d00
JL
1973 }
1974
1da177e4
LT
1975 if (can_sleep)
1976 lock->fl_flags |= FL_SLEEP;
1977
2903ff01 1978 error = security_file_lock(f.file, lock->fl_type);
1da177e4
LT
1979 if (error)
1980 goto out_free;
1981
72c2d531 1982 if (f.file->f_op->flock)
2903ff01 1983 error = f.file->f_op->flock(f.file,
1da177e4
LT
1984 (can_sleep) ? F_SETLKW : F_SETLK,
1985 lock);
1986 else
4f656367 1987 error = locks_lock_file_wait(f.file, lock);
1da177e4
LT
1988
1989 out_free:
993dfa87 1990 locks_free_lock(lock);
1da177e4
LT
1991
1992 out_putf:
2903ff01 1993 fdput(f);
1da177e4
LT
1994 out:
1995 return error;
1996}
1997
3ee17abd
BF
1998/**
1999 * vfs_test_lock - test file byte range lock
2000 * @filp: The file to test lock for
6924c554 2001 * @fl: The lock to test; also used to hold result
3ee17abd
BF
2002 *
2003 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2004 * setting conf->fl_type to something other than F_UNLCK.
2005 */
2006int vfs_test_lock(struct file *filp, struct file_lock *fl)
2007{
72c2d531 2008 if (filp->f_op->lock)
3ee17abd
BF
2009 return filp->f_op->lock(filp, F_GETLK, fl);
2010 posix_test_lock(filp, fl);
2011 return 0;
2012}
2013EXPORT_SYMBOL_GPL(vfs_test_lock);
2014
c2fa1b8a
BF
2015static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2016{
cff2fce5 2017 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
c2fa1b8a
BF
2018#if BITS_PER_LONG == 32
2019 /*
2020 * Make sure we can represent the posix lock via
2021 * legacy 32bit flock.
2022 */
2023 if (fl->fl_start > OFFT_OFFSET_MAX)
2024 return -EOVERFLOW;
2025 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2026 return -EOVERFLOW;
2027#endif
2028 flock->l_start = fl->fl_start;
2029 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2030 fl->fl_end - fl->fl_start + 1;
2031 flock->l_whence = 0;
129a84de 2032 flock->l_type = fl->fl_type;
c2fa1b8a
BF
2033 return 0;
2034}
2035
2036#if BITS_PER_LONG == 32
2037static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2038{
cff2fce5 2039 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
c2fa1b8a
BF
2040 flock->l_start = fl->fl_start;
2041 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2042 fl->fl_end - fl->fl_start + 1;
2043 flock->l_whence = 0;
2044 flock->l_type = fl->fl_type;
2045}
2046#endif
2047
1da177e4
LT
2048/* Report the first existing lock that would conflict with l.
2049 * This implements the F_GETLK command of fcntl().
2050 */
c1e62b8f 2051int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
1da177e4 2052{
9d6a8c5c 2053 struct file_lock file_lock;
1da177e4
LT
2054 struct flock flock;
2055 int error;
2056
2057 error = -EFAULT;
2058 if (copy_from_user(&flock, l, sizeof(flock)))
2059 goto out;
2060 error = -EINVAL;
2061 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2062 goto out;
2063
2064 error = flock_to_posix_lock(filp, &file_lock, &flock);
2065 if (error)
2066 goto out;
2067
0d3f7a2d 2068 if (cmd == F_OFD_GETLK) {
90478939
JL
2069 error = -EINVAL;
2070 if (flock.l_pid != 0)
2071 goto out;
2072
5d50ffd7 2073 cmd = F_GETLK;
cff2fce5 2074 file_lock.fl_flags |= FL_OFDLCK;
73a8f5f7 2075 file_lock.fl_owner = filp;
5d50ffd7
JL
2076 }
2077
3ee17abd
BF
2078 error = vfs_test_lock(filp, &file_lock);
2079 if (error)
2080 goto out;
1da177e4 2081
9d6a8c5c
ME
2082 flock.l_type = file_lock.fl_type;
2083 if (file_lock.fl_type != F_UNLCK) {
2084 error = posix_lock_to_flock(&flock, &file_lock);
c2fa1b8a 2085 if (error)
f328296e 2086 goto rel_priv;
1da177e4
LT
2087 }
2088 error = -EFAULT;
2089 if (!copy_to_user(l, &flock, sizeof(flock)))
2090 error = 0;
f328296e
KM
2091rel_priv:
2092 locks_release_private(&file_lock);
1da177e4
LT
2093out:
2094 return error;
2095}
2096
7723ec97
ME
2097/**
2098 * vfs_lock_file - file byte range lock
2099 * @filp: The file to apply the lock to
2100 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2101 * @fl: The lock to be applied
150b3934
ME
2102 * @conf: Place to return a copy of the conflicting lock, if found.
2103 *
2104 * A caller that doesn't care about the conflicting lock may pass NULL
2105 * as the final argument.
2106 *
2107 * If the filesystem defines a private ->lock() method, then @conf will
2108 * be left unchanged; so a caller that cares should initialize it to
2109 * some acceptable default.
2beb6614
ME
2110 *
2111 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2112 * locks, the ->lock() interface may return asynchronously, before the lock has
2113 * been granted or denied by the underlying filesystem, if (and only if)
8fb47a4f 2114 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2beb6614
ME
2115 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2116 * the request is for a blocking lock. When ->lock() does return asynchronously,
8fb47a4f 2117 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2beb6614
ME
2118 * request completes.
2119 * If the request is for non-blocking lock the file system should return
bde74e4b
MS
2120 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2121 * with the result. If the request timed out the callback routine will return a
2beb6614
ME
2122 * nonzero return code and the file system should release the lock. The file
2123 * system is also responsible to keep a corresponding posix lock when it
2124 * grants a lock so the VFS can find out which locks are locally held and do
2125 * the correct lock cleanup when required.
2126 * The underlying filesystem must not drop the kernel lock or call
8fb47a4f 2127 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2beb6614 2128 * return code.
7723ec97 2129 */
150b3934 2130int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
7723ec97 2131{
72c2d531 2132 if (filp->f_op->lock)
7723ec97
ME
2133 return filp->f_op->lock(filp, cmd, fl);
2134 else
150b3934 2135 return posix_lock_file(filp, fl, conf);
7723ec97
ME
2136}
2137EXPORT_SYMBOL_GPL(vfs_lock_file);
2138
b648a6de
MS
2139static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2140 struct file_lock *fl)
2141{
2142 int error;
2143
2144 error = security_file_lock(filp, fl->fl_type);
2145 if (error)
2146 return error;
2147
764c76b3
MS
2148 for (;;) {
2149 error = vfs_lock_file(filp, cmd, fl, NULL);
2150 if (error != FILE_LOCK_DEFERRED)
b648a6de 2151 break;
764c76b3
MS
2152 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2153 if (!error)
2154 continue;
2155
2156 locks_delete_block(fl);
2157 break;
b648a6de
MS
2158 }
2159
2160 return error;
2161}
2162
6ca7d910 2163/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
cf01f4ee
JL
2164static int
2165check_fmode_for_setlk(struct file_lock *fl)
2166{
2167 switch (fl->fl_type) {
2168 case F_RDLCK:
2169 if (!(fl->fl_file->f_mode & FMODE_READ))
2170 return -EBADF;
2171 break;
2172 case F_WRLCK:
2173 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2174 return -EBADF;
2175 }
2176 return 0;
2177}
2178
1da177e4
LT
2179/* Apply the lock described by l to an open file descriptor.
2180 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2181 */
c293621b
PS
2182int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2183 struct flock __user *l)
1da177e4
LT
2184{
2185 struct file_lock *file_lock = locks_alloc_lock();
2186 struct flock flock;
2187 struct inode *inode;
0b2bac2f 2188 struct file *f;
1da177e4
LT
2189 int error;
2190
2191 if (file_lock == NULL)
2192 return -ENOLCK;
2193
1890910f
JL
2194 inode = file_inode(filp);
2195
1da177e4
LT
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
1da177e4
LT
2203 /* Don't allow mandatory locks on files that may be memory mapped
2204 * and shared.
2205 */
a16877ca 2206 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
1da177e4
LT
2207 error = -EAGAIN;
2208 goto out;
2209 }
2210
2211 error = flock_to_posix_lock(filp, file_lock, &flock);
2212 if (error)
2213 goto out;
5d50ffd7 2214
cf01f4ee
JL
2215 error = check_fmode_for_setlk(file_lock);
2216 if (error)
2217 goto out;
2218
5d50ffd7
JL
2219 /*
2220 * If the cmd is requesting file-private locks, then set the
cff2fce5 2221 * FL_OFDLCK flag and override the owner.
5d50ffd7
JL
2222 */
2223 switch (cmd) {
0d3f7a2d 2224 case F_OFD_SETLK:
90478939
JL
2225 error = -EINVAL;
2226 if (flock.l_pid != 0)
2227 goto out;
2228
5d50ffd7 2229 cmd = F_SETLK;
cff2fce5 2230 file_lock->fl_flags |= FL_OFDLCK;
73a8f5f7 2231 file_lock->fl_owner = filp;
5d50ffd7 2232 break;
0d3f7a2d 2233 case F_OFD_SETLKW:
90478939
JL
2234 error = -EINVAL;
2235 if (flock.l_pid != 0)
2236 goto out;
2237
5d50ffd7 2238 cmd = F_SETLKW;
cff2fce5 2239 file_lock->fl_flags |= FL_OFDLCK;
73a8f5f7 2240 file_lock->fl_owner = filp;
5d50ffd7
JL
2241 /* Fallthrough */
2242 case F_SETLKW:
1da177e4
LT
2243 file_lock->fl_flags |= FL_SLEEP;
2244 }
5d50ffd7 2245
b648a6de 2246 error = do_lock_file_wait(filp, cmd, file_lock);
1da177e4 2247
c293621b 2248 /*
0752ba80
JL
2249 * Attempt to detect a close/fcntl race and recover by releasing the
2250 * lock that was just acquired. There is no need to do that when we're
2251 * unlocking though, or for OFD locks.
c293621b 2252 */
0752ba80
JL
2253 if (!error && file_lock->fl_type != F_UNLCK &&
2254 !(file_lock->fl_flags & FL_OFDLCK)) {
7f3697e2
JL
2255 /*
2256 * We need that spin_lock here - it prevents reordering between
2257 * update of i_flctx->flc_posix and check for it done in
2258 * close(). rcu_read_lock() wouldn't do.
2259 */
2260 spin_lock(&current->files->file_lock);
2261 f = fcheck(fd);
2262 spin_unlock(&current->files->file_lock);
2263 if (f != filp) {
2264 file_lock->fl_type = F_UNLCK;
2265 error = do_lock_file_wait(filp, cmd, file_lock);
2266 WARN_ON_ONCE(error);
2267 error = -EBADF;
2268 }
1da177e4 2269 }
c293621b 2270out:
1890910f 2271 trace_fcntl_setlk(inode, file_lock, error);
1da177e4
LT
2272 locks_free_lock(file_lock);
2273 return error;
2274}
2275
2276#if BITS_PER_LONG == 32
2277/* Report the first existing lock that would conflict with l.
2278 * This implements the F_GETLK command of fcntl().
2279 */
c1e62b8f 2280int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
1da177e4 2281{
9d6a8c5c 2282 struct file_lock file_lock;
1da177e4
LT
2283 struct flock64 flock;
2284 int error;
2285
2286 error = -EFAULT;
2287 if (copy_from_user(&flock, l, sizeof(flock)))
2288 goto out;
2289 error = -EINVAL;
2290 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2291 goto out;
2292
2293 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2294 if (error)
2295 goto out;
2296
0d3f7a2d 2297 if (cmd == F_OFD_GETLK) {
90478939
JL
2298 error = -EINVAL;
2299 if (flock.l_pid != 0)
2300 goto out;
2301
5d50ffd7 2302 cmd = F_GETLK64;
cff2fce5 2303 file_lock.fl_flags |= FL_OFDLCK;
73a8f5f7 2304 file_lock.fl_owner = filp;
5d50ffd7
JL
2305 }
2306
3ee17abd
BF
2307 error = vfs_test_lock(filp, &file_lock);
2308 if (error)
2309 goto out;
2310
9d6a8c5c
ME
2311 flock.l_type = file_lock.fl_type;
2312 if (file_lock.fl_type != F_UNLCK)
2313 posix_lock_to_flock64(&flock, &file_lock);
2314
1da177e4
LT
2315 error = -EFAULT;
2316 if (!copy_to_user(l, &flock, sizeof(flock)))
2317 error = 0;
f328296e
KM
2318
2319 locks_release_private(&file_lock);
1da177e4
LT
2320out:
2321 return error;
2322}
2323
2324/* Apply the lock described by l to an open file descriptor.
2325 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2326 */
c293621b
PS
2327int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2328 struct flock64 __user *l)
1da177e4
LT
2329{
2330 struct file_lock *file_lock = locks_alloc_lock();
2331 struct flock64 flock;
2332 struct inode *inode;
0b2bac2f 2333 struct file *f;
1da177e4
LT
2334 int error;
2335
2336 if (file_lock == NULL)
2337 return -ENOLCK;
2338
2339 /*
2340 * This might block, so we do it before checking the inode.
2341 */
2342 error = -EFAULT;
2343 if (copy_from_user(&flock, l, sizeof(flock)))
2344 goto out;
2345
496ad9aa 2346 inode = file_inode(filp);
1da177e4
LT
2347
2348 /* Don't allow mandatory locks on files that may be memory mapped
2349 * and shared.
2350 */
a16877ca 2351 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
1da177e4
LT
2352 error = -EAGAIN;
2353 goto out;
2354 }
2355
2356 error = flock64_to_posix_lock(filp, file_lock, &flock);
2357 if (error)
2358 goto out;
5d50ffd7 2359
cf01f4ee
JL
2360 error = check_fmode_for_setlk(file_lock);
2361 if (error)
2362 goto out;
2363
5d50ffd7
JL
2364 /*
2365 * If the cmd is requesting file-private locks, then set the
cff2fce5 2366 * FL_OFDLCK flag and override the owner.
5d50ffd7
JL
2367 */
2368 switch (cmd) {
0d3f7a2d 2369 case F_OFD_SETLK:
90478939
JL
2370 error = -EINVAL;
2371 if (flock.l_pid != 0)
2372 goto out;
2373
5d50ffd7 2374 cmd = F_SETLK64;
cff2fce5 2375 file_lock->fl_flags |= FL_OFDLCK;
73a8f5f7 2376 file_lock->fl_owner = filp;
5d50ffd7 2377 break;
0d3f7a2d 2378 case F_OFD_SETLKW:
90478939
JL
2379 error = -EINVAL;
2380 if (flock.l_pid != 0)
2381 goto out;
2382
5d50ffd7 2383 cmd = F_SETLKW64;
cff2fce5 2384 file_lock->fl_flags |= FL_OFDLCK;
73a8f5f7 2385 file_lock->fl_owner = filp;
5d50ffd7
JL
2386 /* Fallthrough */
2387 case F_SETLKW64:
1da177e4
LT
2388 file_lock->fl_flags |= FL_SLEEP;
2389 }
5d50ffd7 2390
b648a6de 2391 error = do_lock_file_wait(filp, cmd, file_lock);
1da177e4 2392
c293621b 2393 /*
0752ba80
JL
2394 * Attempt to detect a close/fcntl race and recover by releasing the
2395 * lock that was just acquired. There is no need to do that when we're
2396 * unlocking though, or for OFD locks.
c293621b 2397 */
0752ba80
JL
2398 if (!error && file_lock->fl_type != F_UNLCK &&
2399 !(file_lock->fl_flags & FL_OFDLCK)) {
7f3697e2
JL
2400 /*
2401 * We need that spin_lock here - it prevents reordering between
2402 * update of i_flctx->flc_posix and check for it done in
2403 * close(). rcu_read_lock() wouldn't do.
2404 */
2405 spin_lock(&current->files->file_lock);
2406 f = fcheck(fd);
2407 spin_unlock(&current->files->file_lock);
2408 if (f != filp) {
2409 file_lock->fl_type = F_UNLCK;
2410 error = do_lock_file_wait(filp, cmd, file_lock);
2411 WARN_ON_ONCE(error);
2412 error = -EBADF;
2413 }
1da177e4 2414 }
1da177e4
LT
2415out:
2416 locks_free_lock(file_lock);
2417 return error;
2418}
2419#endif /* BITS_PER_LONG == 32 */
2420
2421/*
2422 * This function is called when the file is being removed
2423 * from the task's fd array. POSIX locks belonging to this task
2424 * are deleted at this time.
2425 */
2426void locks_remove_posix(struct file *filp, fl_owner_t owner)
2427{
1890910f 2428 int error;
ff7b86b8 2429 struct file_lock lock;
128a3785 2430 struct file_lock_context *ctx;
1da177e4
LT
2431
2432 /*
2433 * If there are no locks held on this file, we don't need to call
2434 * posix_lock_file(). Another process could be setting a lock on this
2435 * file at the same time, but we wouldn't remove that lock anyway.
2436 */
128a3785 2437 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
bd61e0a9 2438 if (!ctx || list_empty(&ctx->flc_posix))
1da177e4
LT
2439 return;
2440
2441 lock.fl_type = F_UNLCK;
75e1fcc0 2442 lock.fl_flags = FL_POSIX | FL_CLOSE;
1da177e4
LT
2443 lock.fl_start = 0;
2444 lock.fl_end = OFFSET_MAX;
2445 lock.fl_owner = owner;
2446 lock.fl_pid = current->tgid;
2447 lock.fl_file = filp;
2448 lock.fl_ops = NULL;
2449 lock.fl_lmops = NULL;
2450
1890910f 2451 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
1da177e4 2452
1da177e4
LT
2453 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2454 lock.fl_ops->fl_release_private(&lock);
1890910f 2455 trace_locks_remove_posix(file_inode(filp), &lock, error);
1da177e4
LT
2456}
2457
2458EXPORT_SYMBOL(locks_remove_posix);
2459
3d8e560d 2460/* The i_flctx must be valid when calling into here */
dd459bb1 2461static void
128a3785 2462locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
dd459bb1
JL
2463{
2464 struct file_lock fl = {
2465 .fl_owner = filp,
2466 .fl_pid = current->tgid,
2467 .fl_file = filp,
2468 .fl_flags = FL_FLOCK,
2469 .fl_type = F_UNLCK,
2470 .fl_end = OFFSET_MAX,
2471 };
bcd7f78d 2472 struct inode *inode = file_inode(filp);
dd459bb1 2473
3d8e560d 2474 if (list_empty(&flctx->flc_flock))
dd459bb1
JL
2475 return;
2476
2477 if (filp->f_op->flock)
2478 filp->f_op->flock(filp, F_SETLKW, &fl);
2479 else
bcd7f78d 2480 flock_lock_inode(inode, &fl);
dd459bb1
JL
2481
2482 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2483 fl.fl_ops->fl_release_private(&fl);
2484}
2485
3d8e560d 2486/* The i_flctx must be valid when calling into here */
8634b51f 2487static void
128a3785 2488locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
8634b51f 2489{
8634b51f
JL
2490 struct file_lock *fl, *tmp;
2491 LIST_HEAD(dispose);
2492
3d8e560d 2493 if (list_empty(&ctx->flc_lease))
8634b51f
JL
2494 return;
2495
6109c850 2496 spin_lock(&ctx->flc_lock);
8634b51f 2497 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
c4e136cd
JL
2498 if (filp == fl->fl_file)
2499 lease_modify(fl, F_UNLCK, &dispose);
6109c850 2500 spin_unlock(&ctx->flc_lock);
8634b51f
JL
2501 locks_dispose_list(&dispose);
2502}
2503
1da177e4
LT
2504/*
2505 * This function is called on the last close of an open file.
2506 */
78ed8a13 2507void locks_remove_file(struct file *filp)
1da177e4 2508{
128a3785
DV
2509 struct file_lock_context *ctx;
2510
2511 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
2512 if (!ctx)
3d8e560d
JL
2513 return;
2514
dd459bb1 2515 /* remove any OFD locks */
73a8f5f7 2516 locks_remove_posix(filp, filp);
5d50ffd7 2517
dd459bb1 2518 /* remove flock locks */
128a3785 2519 locks_remove_flock(filp, ctx);
dd459bb1 2520
8634b51f 2521 /* remove any leases */
128a3785 2522 locks_remove_lease(filp, ctx);
1da177e4
LT
2523}
2524
1da177e4
LT
2525/**
2526 * posix_unblock_lock - stop waiting for a file lock
1da177e4
LT
2527 * @waiter: the lock which was waiting
2528 *
2529 * lockd needs to block waiting for locks.
2530 */
64a318ee 2531int
f891a29f 2532posix_unblock_lock(struct file_lock *waiter)
1da177e4 2533{
64a318ee
BF
2534 int status = 0;
2535
7b2296af 2536 spin_lock(&blocked_lock_lock);
5996a298 2537 if (waiter->fl_next)
1da177e4 2538 __locks_delete_block(waiter);
64a318ee
BF
2539 else
2540 status = -ENOENT;
7b2296af 2541 spin_unlock(&blocked_lock_lock);
64a318ee 2542 return status;
1da177e4 2543}
1da177e4
LT
2544EXPORT_SYMBOL(posix_unblock_lock);
2545
9b9d2ab4
ME
2546/**
2547 * vfs_cancel_lock - file byte range unblock lock
2548 * @filp: The file to apply the unblock to
2549 * @fl: The lock to be unblocked
2550 *
2551 * Used by lock managers to cancel blocked requests
2552 */
2553int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2554{
72c2d531 2555 if (filp->f_op->lock)
9b9d2ab4
ME
2556 return filp->f_op->lock(filp, F_CANCELLK, fl);
2557 return 0;
2558}
2559
2560EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2561
7f8ada98 2562#ifdef CONFIG_PROC_FS
d8ba7a36 2563#include <linux/proc_fs.h>
7f8ada98
PE
2564#include <linux/seq_file.h>
2565
7012b02a
JL
2566struct locks_iterator {
2567 int li_cpu;
2568 loff_t li_pos;
2569};
2570
7f8ada98 2571static void lock_get_status(struct seq_file *f, struct file_lock *fl,
99dc8292 2572 loff_t id, char *pfx)
1da177e4
LT
2573{
2574 struct inode *inode = NULL;
ab1f1611
VG
2575 unsigned int fl_pid;
2576
2577 if (fl->fl_nspid)
6c5f3e7b 2578 fl_pid = pid_vnr(fl->fl_nspid);
ab1f1611
VG
2579 else
2580 fl_pid = fl->fl_pid;
1da177e4
LT
2581
2582 if (fl->fl_file != NULL)
496ad9aa 2583 inode = file_inode(fl->fl_file);
1da177e4 2584
99dc8292 2585 seq_printf(f, "%lld:%s ", id, pfx);
1da177e4 2586 if (IS_POSIX(fl)) {
c918d42a 2587 if (fl->fl_flags & FL_ACCESS)
5315c26a 2588 seq_puts(f, "ACCESS");
cff2fce5 2589 else if (IS_OFDLCK(fl))
5315c26a 2590 seq_puts(f, "OFDLCK");
c918d42a 2591 else
5315c26a 2592 seq_puts(f, "POSIX ");
c918d42a
JL
2593
2594 seq_printf(f, " %s ",
1da177e4 2595 (inode == NULL) ? "*NOINODE*" :
a16877ca 2596 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
1da177e4
LT
2597 } else if (IS_FLOCK(fl)) {
2598 if (fl->fl_type & LOCK_MAND) {
5315c26a 2599 seq_puts(f, "FLOCK MSNFS ");
1da177e4 2600 } else {
5315c26a 2601 seq_puts(f, "FLOCK ADVISORY ");
1da177e4
LT
2602 }
2603 } else if (IS_LEASE(fl)) {
8144f1f6
JL
2604 if (fl->fl_flags & FL_DELEG)
2605 seq_puts(f, "DELEG ");
2606 else
2607 seq_puts(f, "LEASE ");
2608
ab83fa4b 2609 if (lease_breaking(fl))
5315c26a 2610 seq_puts(f, "BREAKING ");
1da177e4 2611 else if (fl->fl_file)
5315c26a 2612 seq_puts(f, "ACTIVE ");
1da177e4 2613 else
5315c26a 2614 seq_puts(f, "BREAKER ");
1da177e4 2615 } else {
5315c26a 2616 seq_puts(f, "UNKNOWN UNKNOWN ");
1da177e4
LT
2617 }
2618 if (fl->fl_type & LOCK_MAND) {
7f8ada98 2619 seq_printf(f, "%s ",
1da177e4
LT
2620 (fl->fl_type & LOCK_READ)
2621 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2622 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2623 } else {
7f8ada98 2624 seq_printf(f, "%s ",
ab83fa4b 2625 (lease_breaking(fl))
0ee5c6d6
JL
2626 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2627 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
1da177e4
LT
2628 }
2629 if (inode) {
3648888e 2630 /* userspace relies on this representation of dev_t */
ab1f1611 2631 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
1da177e4
LT
2632 MAJOR(inode->i_sb->s_dev),
2633 MINOR(inode->i_sb->s_dev), inode->i_ino);
1da177e4 2634 } else {
ab1f1611 2635 seq_printf(f, "%d <none>:0 ", fl_pid);
1da177e4
LT
2636 }
2637 if (IS_POSIX(fl)) {
2638 if (fl->fl_end == OFFSET_MAX)
7f8ada98 2639 seq_printf(f, "%Ld EOF\n", fl->fl_start);
1da177e4 2640 else
7f8ada98 2641 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
1da177e4 2642 } else {
5315c26a 2643 seq_puts(f, "0 EOF\n");
1da177e4
LT
2644 }
2645}
2646
7f8ada98 2647static int locks_show(struct seq_file *f, void *v)
1da177e4 2648{
7012b02a 2649 struct locks_iterator *iter = f->private;
7f8ada98 2650 struct file_lock *fl, *bfl;
1da177e4 2651
139ca04e 2652 fl = hlist_entry(v, struct file_lock, fl_link);
1da177e4 2653
7012b02a 2654 lock_get_status(f, fl, iter->li_pos, "");
1da177e4 2655
7f8ada98 2656 list_for_each_entry(bfl, &fl->fl_block, fl_block)
7012b02a 2657 lock_get_status(f, bfl, iter->li_pos, " ->");
094f2825 2658
7f8ada98
PE
2659 return 0;
2660}
1da177e4 2661
6c8c9031
AV
2662static void __show_fd_locks(struct seq_file *f,
2663 struct list_head *head, int *id,
2664 struct file *filp, struct files_struct *files)
2665{
2666 struct file_lock *fl;
2667
2668 list_for_each_entry(fl, head, fl_list) {
2669
2670 if (filp != fl->fl_file)
2671 continue;
2672 if (fl->fl_owner != files &&
2673 fl->fl_owner != filp)
2674 continue;
2675
2676 (*id)++;
2677 seq_puts(f, "lock:\t");
2678 lock_get_status(f, fl, *id, "");
2679 }
2680}
2681
2682void show_fd_locks(struct seq_file *f,
2683 struct file *filp, struct files_struct *files)
2684{
2685 struct inode *inode = file_inode(filp);
2686 struct file_lock_context *ctx;
2687 int id = 0;
2688
128a3785 2689 ctx = smp_load_acquire(&inode->i_flctx);
6c8c9031
AV
2690 if (!ctx)
2691 return;
2692
2693 spin_lock(&ctx->flc_lock);
2694 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2695 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2696 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2697 spin_unlock(&ctx->flc_lock);
2698}
2699
7f8ada98 2700static void *locks_start(struct seq_file *f, loff_t *pos)
b03dfdec 2701 __acquires(&blocked_lock_lock)
7f8ada98 2702{
7012b02a 2703 struct locks_iterator *iter = f->private;
99dc8292 2704
7012b02a
JL
2705 iter->li_pos = *pos + 1;
2706 lg_global_lock(&file_lock_lglock);
7b2296af 2707 spin_lock(&blocked_lock_lock);
7012b02a 2708 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
7f8ada98 2709}
1da177e4 2710
7f8ada98
PE
2711static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2712{
7012b02a
JL
2713 struct locks_iterator *iter = f->private;
2714
2715 ++iter->li_pos;
2716 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
7f8ada98 2717}
1da177e4 2718
7f8ada98 2719static void locks_stop(struct seq_file *f, void *v)
b03dfdec 2720 __releases(&blocked_lock_lock)
7f8ada98 2721{
7b2296af 2722 spin_unlock(&blocked_lock_lock);
7012b02a 2723 lg_global_unlock(&file_lock_lglock);
1da177e4
LT
2724}
2725
d8ba7a36 2726static const struct seq_operations locks_seq_operations = {
7f8ada98
PE
2727 .start = locks_start,
2728 .next = locks_next,
2729 .stop = locks_stop,
2730 .show = locks_show,
2731};
d8ba7a36
AD
2732
2733static int locks_open(struct inode *inode, struct file *filp)
2734{
7012b02a
JL
2735 return seq_open_private(filp, &locks_seq_operations,
2736 sizeof(struct locks_iterator));
d8ba7a36
AD
2737}
2738
2739static const struct file_operations proc_locks_operations = {
2740 .open = locks_open,
2741 .read = seq_read,
2742 .llseek = seq_lseek,
99dc8292 2743 .release = seq_release_private,
d8ba7a36
AD
2744};
2745
2746static int __init proc_locks_init(void)
2747{
2748 proc_create("locks", 0, NULL, &proc_locks_operations);
2749 return 0;
2750}
91899226 2751fs_initcall(proc_locks_init);
7f8ada98
PE
2752#endif
2753
1da177e4
LT
2754static int __init filelock_init(void)
2755{
7012b02a
JL
2756 int i;
2757
4a075e39
JL
2758 flctx_cache = kmem_cache_create("file_lock_ctx",
2759 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2760
1da177e4 2761 filelock_cache = kmem_cache_create("file_lock_cache",
ee19cc40
MS
2762 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2763
7012b02a
JL
2764 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2765
2766 for_each_possible_cpu(i)
2767 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2768
1da177e4
LT
2769 return 0;
2770}
2771
2772core_initcall(filelock_init);