Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0-only
2 : : /*
3 : : * linux/fs/locks.c
4 : : *
5 : : * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
6 : : * Doug Evans (dje@spiff.uucp), August 07, 1992
7 : : *
8 : : * Deadlock detection added.
9 : : * FIXME: one thing isn't handled yet:
10 : : * - mandatory locks (requires lots of changes elsewhere)
11 : : * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
12 : : *
13 : : * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
14 : : * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
15 : : *
16 : : * Converted file_lock_table to a linked list from an array, which eliminates
17 : : * the limits on how many active file locks are open.
18 : : * Chad Page (pageone@netcom.com), November 27, 1994
19 : : *
20 : : * Removed dependency on file descriptors. dup()'ed file descriptors now
21 : : * get the same locks as the original file descriptors, and a close() on
22 : : * any file descriptor removes ALL the locks on the file for the current
23 : : * process. Since locks still depend on the process id, locks are inherited
24 : : * after an exec() but not after a fork(). This agrees with POSIX, and both
25 : : * BSD and SVR4 practice.
26 : : * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
27 : : *
28 : : * Scrapped free list which is redundant now that we allocate locks
29 : : * dynamically with kmalloc()/kfree().
30 : : * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
31 : : *
32 : : * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
33 : : *
34 : : * FL_POSIX locks are created with calls to fcntl() and lockf() through the
35 : : * fcntl() system call. They have the semantics described above.
36 : : *
37 : : * FL_FLOCK locks are created with calls to flock(), through the flock()
38 : : * system call, which is new. Old C libraries implement flock() via fcntl()
39 : : * and will continue to use the old, broken implementation.
40 : : *
41 : : * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
42 : : * with a file pointer (filp). As a result they can be shared by a parent
43 : : * process and its children after a fork(). They are removed when the last
44 : : * file descriptor referring to the file pointer is closed (unless explicitly
45 : : * unlocked).
46 : : *
47 : : * FL_FLOCK locks never deadlock, an existing lock is always removed before
48 : : * upgrading from shared to exclusive (or vice versa). When this happens
49 : : * any processes blocked by the current lock are woken up and allowed to
50 : : * run before the new lock is applied.
51 : : * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
52 : : *
53 : : * Removed some race conditions in flock_lock_file(), marked other possible
54 : : * races. Just grep for FIXME to see them.
55 : : * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
56 : : *
57 : : * Addressed Dmitry's concerns. Deadlock checking no longer recursive.
58 : : * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
59 : : * once we've checked for blocking and deadlocking.
60 : : * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
61 : : *
62 : : * Initial implementation of mandatory locks. SunOS turned out to be
63 : : * a rotten model, so I implemented the "obvious" semantics.
64 : : * See 'Documentation/filesystems/mandatory-locking.txt' for details.
65 : : * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
66 : : *
67 : : * Don't allow mandatory locks on mmap()'ed files. Added simple functions to
68 : : * check if a file has mandatory locks, used by mmap(), open() and creat() to
69 : : * see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
70 : : * Manual, Section 2.
71 : : * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
72 : : *
73 : : * Tidied up block list handling. Added '/proc/locks' interface.
74 : : * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
75 : : *
76 : : * Fixed deadlock condition for pathological code that mixes calls to
77 : : * flock() and fcntl().
78 : : * Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
79 : : *
80 : : * Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
81 : : * for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
82 : : * guarantee sensible behaviour in the case where file system modules might
83 : : * be compiled with different options than the kernel itself.
84 : : * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
85 : : *
86 : : * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
87 : : * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
88 : : * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
89 : : *
90 : : * Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
91 : : * locks. Changed process synchronisation to avoid dereferencing locks that
92 : : * have already been freed.
93 : : * Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
94 : : *
95 : : * Made the block list a circular list to minimise searching in the list.
96 : : * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
97 : : *
98 : : * Made mandatory locking a mount option. Default is not to allow mandatory
99 : : * locking.
100 : : * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
101 : : *
102 : : * Some adaptations for NFS support.
103 : : * Olaf Kirch (okir@monad.swb.de), Dec 1996,
104 : : *
105 : : * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
106 : : * Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
107 : : *
108 : : * Use slab allocator instead of kmalloc/kfree.
109 : : * Use generic list implementation from <linux/list.h>.
110 : : * Sped up posix_locks_deadlock by only considering blocked locks.
111 : : * Matthew Wilcox <willy@debian.org>, March, 2000.
112 : : *
113 : : * Leases and LOCK_MAND
114 : : * Matthew Wilcox <willy@debian.org>, June, 2000.
115 : : * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
116 : : *
117 : : * Locking conflicts and dependencies:
118 : : * If multiple threads attempt to lock the same byte (or flock the same file)
119 : : * only one can be granted the lock, and other must wait their turn.
120 : : * The first lock has been "applied" or "granted", the others are "waiting"
121 : : * and are "blocked" by the "applied" lock..
122 : : *
123 : : * Waiting and applied locks are all kept in trees whose properties are:
124 : : *
125 : : * - the root of a tree may be an applied or waiting lock.
126 : : * - every other node in the tree is a waiting lock that
127 : : * conflicts with every ancestor of that node.
128 : : *
129 : : * Every such tree begins life as a waiting singleton which obviously
130 : : * satisfies the above properties.
131 : : *
132 : : * The only ways we modify trees preserve these properties:
133 : : *
134 : : * 1. We may add a new leaf node, but only after first verifying that it
135 : : * conflicts with all of its ancestors.
136 : : * 2. We may remove the root of a tree, creating a new singleton
137 : : * tree from the root and N new trees rooted in the immediate
138 : : * children.
139 : : * 3. If the root of a tree is not currently an applied lock, we may
140 : : * apply it (if possible).
141 : : * 4. We may upgrade the root of the tree (either extend its range,
142 : : * or upgrade its entire range from read to write).
143 : : *
144 : : * When an applied lock is modified in a way that reduces or downgrades any
145 : : * part of its range, we remove all its children (2 above). This particularly
146 : : * happens when a lock is unlocked.
147 : : *
148 : : * For each of those child trees we "wake up" the thread which is
149 : : * waiting for the lock so it can continue handling as follows: if the
150 : : * root of the tree applies, we do so (3). If it doesn't, it must
151 : : * conflict with some applied lock. We remove (wake up) all of its children
152 : : * (2), and add it is a new leaf to the tree rooted in the applied
153 : : * lock (1). We then repeat the process recursively with those
154 : : * children.
155 : : *
156 : : */
157 : :
158 : : #include <linux/capability.h>
159 : : #include <linux/file.h>
160 : : #include <linux/fdtable.h>
161 : : #include <linux/fs.h>
162 : : #include <linux/init.h>
163 : : #include <linux/security.h>
164 : : #include <linux/slab.h>
165 : : #include <linux/syscalls.h>
166 : : #include <linux/time.h>
167 : : #include <linux/rcupdate.h>
168 : : #include <linux/pid_namespace.h>
169 : : #include <linux/hashtable.h>
170 : : #include <linux/percpu.h>
171 : :
172 : : #define CREATE_TRACE_POINTS
173 : : #include <trace/events/filelock.h>
174 : :
175 : : #include <linux/uaccess.h>
176 : :
177 : : #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
178 : : #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
179 : : #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
180 : : #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
181 : : #define IS_REMOTELCK(fl) (fl->fl_pid <= 0)
182 : :
183 : 0 : static bool lease_breaking(struct file_lock *fl)
184 : : {
185 : 0 : return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
186 : : }
187 : :
188 : 0 : static int target_leasetype(struct file_lock *fl)
189 : : {
190 [ # # ]: 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
191 : : return F_UNLCK;
192 [ # # # # ]: 0 : if (fl->fl_flags & FL_DOWNGRADE_PENDING)
193 : : return F_RDLCK;
194 : 0 : return fl->fl_type;
195 : : }
196 : :
197 : : int leases_enable = 1;
198 : : int lease_break_time = 45;
199 : :
200 : : /*
201 : : * The global file_lock_list is only used for displaying /proc/locks, so we
202 : : * keep a list on each CPU, with each list protected by its own spinlock.
203 : : * Global serialization is done using file_rwsem.
204 : : *
205 : : * Note that alterations to the list also require that the relevant flc_lock is
206 : : * held.
207 : : */
208 : : struct file_lock_list_struct {
209 : : spinlock_t lock;
210 : : struct hlist_head hlist;
211 : : };
212 : : static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
213 : : DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
214 : :
215 : :
216 : : /*
217 : : * The blocked_hash is used to find POSIX lock loops for deadlock detection.
218 : : * It is protected by blocked_lock_lock.
219 : : *
220 : : * We hash locks by lockowner in order to optimize searching for the lock a
221 : : * particular lockowner is waiting on.
222 : : *
223 : : * FIXME: make this value scale via some heuristic? We generally will want more
224 : : * buckets when we have more lockowners holding locks, but that's a little
225 : : * difficult to determine without knowing what the workload will look like.
226 : : */
227 : : #define BLOCKED_HASH_BITS 7
228 : : static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
229 : :
230 : : /*
231 : : * This lock protects the blocked_hash. Generally, if you're accessing it, you
232 : : * want to be holding this lock.
233 : : *
234 : : * In addition, it also protects the fl->fl_blocked_requests list, and the
235 : : * fl->fl_blocker pointer for file_lock structures that are acting as lock
236 : : * requests (in contrast to those that are acting as records of acquired locks).
237 : : *
238 : : * Note that when we acquire this lock in order to change the above fields,
239 : : * we often hold the flc_lock as well. In certain cases, when reading the fields
240 : : * protected by this lock, we can skip acquiring it iff we already hold the
241 : : * flc_lock.
242 : : */
243 : : static DEFINE_SPINLOCK(blocked_lock_lock);
244 : :
245 : : static struct kmem_cache *flctx_cache __read_mostly;
246 : : static struct kmem_cache *filelock_cache __read_mostly;
247 : :
248 : : static struct file_lock_context *
249 : 4290 : locks_get_lock_context(struct inode *inode, int type)
250 : : {
251 : 4290 : struct file_lock_context *ctx;
252 : :
253 : : /* paired with cmpxchg() below */
254 : 4290 : ctx = smp_load_acquire(&inode->i_flctx);
255 [ + + - + ]: 4290 : if (likely(ctx) || type == F_UNLCK)
256 : 2886 : goto out;
257 : :
258 : 1404 : ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
259 [ - + ]: 1404 : if (!ctx)
260 : 0 : goto out;
261 : :
262 : 1404 : spin_lock_init(&ctx->flc_lock);
263 : 1404 : INIT_LIST_HEAD(&ctx->flc_flock);
264 : 1404 : INIT_LIST_HEAD(&ctx->flc_posix);
265 : 1404 : INIT_LIST_HEAD(&ctx->flc_lease);
266 : :
267 : : /*
268 : : * Assign the pointer if it's not already assigned. If it is, then
269 : : * free the context we just allocated.
270 : : */
271 [ + - ]: 1404 : if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
272 : 0 : kmem_cache_free(flctx_cache, ctx);
273 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
274 : : }
275 : 1404 : out:
276 : 4290 : trace_locks_get_lock_context(inode, type, ctx);
277 : 4290 : return ctx;
278 : : }
279 : :
280 : : static void
281 : 0 : locks_dump_ctx_list(struct list_head *list, char *list_type)
282 : : {
283 : 0 : struct file_lock *fl;
284 : :
285 [ # # ]: 0 : list_for_each_entry(fl, list, fl_list) {
286 : 0 : 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);
287 : : }
288 : 0 : }
289 : :
290 : : static void
291 : 156 : locks_check_ctx_lists(struct inode *inode)
292 : : {
293 : 156 : struct file_lock_context *ctx = inode->i_flctx;
294 : :
295 [ + - + - : 156 : if (unlikely(!list_empty(&ctx->flc_flock) ||
- + ]
296 : : !list_empty(&ctx->flc_posix) ||
297 : : !list_empty(&ctx->flc_lease))) {
298 : 0 : pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
299 : : MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
300 : : inode->i_ino);
301 : 0 : locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
302 : 0 : locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
303 : 0 : locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
304 : : }
305 : 156 : }
306 : :
307 : : static void
308 : 7722 : locks_check_ctx_file_list(struct file *filp, struct list_head *list,
309 : : char *list_type)
310 : : {
311 : 7722 : struct file_lock *fl;
312 : 7722 : struct inode *inode = locks_inode(filp);
313 : :
314 [ + + ]: 8814 : list_for_each_entry(fl, list, fl_list)
315 [ - + ]: 1092 : if (fl->fl_file == filp)
316 : 0 : pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%lx "
317 : : " fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
318 : : list_type, MAJOR(inode->i_sb->s_dev),
319 : : MINOR(inode->i_sb->s_dev), inode->i_ino,
320 : : fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
321 : 7722 : }
322 : :
323 : : void
324 : 142609 : locks_free_lock_context(struct inode *inode)
325 : : {
326 : 142609 : struct file_lock_context *ctx = inode->i_flctx;
327 : :
328 [ + + ]: 142609 : if (unlikely(ctx)) {
329 : 156 : locks_check_ctx_lists(inode);
330 : 156 : kmem_cache_free(flctx_cache, ctx);
331 : : }
332 : 142609 : }
333 : :
334 : 6318 : static void locks_init_lock_heads(struct file_lock *fl)
335 : : {
336 : 6318 : INIT_HLIST_NODE(&fl->fl_link);
337 : 6318 : INIT_LIST_HEAD(&fl->fl_list);
338 : 6318 : INIT_LIST_HEAD(&fl->fl_blocked_requests);
339 : 6318 : INIT_LIST_HEAD(&fl->fl_blocked_member);
340 : 6318 : init_waitqueue_head(&fl->fl_wait);
341 : 3588 : }
342 : :
343 : : /* Allocate an empty lock structure. */
344 : 3588 : struct file_lock *locks_alloc_lock(void)
345 : : {
346 : 3588 : struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
347 : :
348 [ + - ]: 3588 : if (fl)
349 : 3588 : locks_init_lock_heads(fl);
350 : :
351 : 3588 : return fl;
352 : : }
353 : : EXPORT_SYMBOL_GPL(locks_alloc_lock);
354 : :
355 : 3510 : void locks_release_private(struct file_lock *fl)
356 : : {
357 [ - + ]: 3510 : BUG_ON(waitqueue_active(&fl->fl_wait));
358 [ - + ]: 3510 : BUG_ON(!list_empty(&fl->fl_list));
359 [ - + ]: 3510 : BUG_ON(!list_empty(&fl->fl_blocked_requests));
360 [ - + ]: 3510 : BUG_ON(!list_empty(&fl->fl_blocked_member));
361 [ - + ]: 3510 : BUG_ON(!hlist_unhashed(&fl->fl_link));
362 : :
363 [ - + ]: 3510 : if (fl->fl_ops) {
364 [ # # ]: 0 : if (fl->fl_ops->fl_release_private)
365 : 0 : fl->fl_ops->fl_release_private(fl);
366 : 0 : fl->fl_ops = NULL;
367 : : }
368 : :
369 [ - + ]: 3510 : if (fl->fl_lmops) {
370 [ # # ]: 0 : if (fl->fl_lmops->lm_put_owner) {
371 : 0 : fl->fl_lmops->lm_put_owner(fl->fl_owner);
372 : 0 : fl->fl_owner = NULL;
373 : : }
374 : 0 : fl->fl_lmops = NULL;
375 : : }
376 : 3510 : }
377 : : EXPORT_SYMBOL_GPL(locks_release_private);
378 : :
379 : : /* Free a lock which is not in use. */
380 : 3510 : void locks_free_lock(struct file_lock *fl)
381 : : {
382 : 0 : locks_release_private(fl);
383 : 2886 : kmem_cache_free(filelock_cache, fl);
384 : 2886 : }
385 : : EXPORT_SYMBOL(locks_free_lock);
386 : :
387 : : static void
388 : 4290 : locks_dispose_list(struct list_head *dispose)
389 : : {
390 : 4290 : struct file_lock *fl;
391 : :
392 [ + + ]: 5694 : while (!list_empty(dispose)) {
393 : 1404 : fl = list_first_entry(dispose, struct file_lock, fl_list);
394 : 1404 : list_del_init(&fl->fl_list);
395 : 1404 : locks_free_lock(fl);
396 : : }
397 : 4290 : }
398 : :
399 : 2730 : void locks_init_lock(struct file_lock *fl)
400 : : {
401 : 2730 : memset(fl, 0, sizeof(struct file_lock));
402 : 2730 : locks_init_lock_heads(fl);
403 : 2730 : }
404 : : EXPORT_SYMBOL(locks_init_lock);
405 : :
406 : : /*
407 : : * Initialize a new lock from an existing file_lock structure.
408 : : */
409 : 1482 : void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
410 : : {
411 : 1482 : new->fl_owner = fl->fl_owner;
412 : 1482 : new->fl_pid = fl->fl_pid;
413 : 1482 : new->fl_file = NULL;
414 : 1482 : new->fl_flags = fl->fl_flags;
415 : 1482 : new->fl_type = fl->fl_type;
416 : 1482 : new->fl_start = fl->fl_start;
417 : 1482 : new->fl_end = fl->fl_end;
418 : 1482 : new->fl_lmops = fl->fl_lmops;
419 : 1482 : new->fl_ops = NULL;
420 : :
421 [ - + ]: 1482 : if (fl->fl_lmops) {
422 [ # # ]: 0 : if (fl->fl_lmops->lm_get_owner)
423 : 0 : fl->fl_lmops->lm_get_owner(fl->fl_owner);
424 : : }
425 : 1482 : }
426 : : EXPORT_SYMBOL(locks_copy_conflock);
427 : :
428 : 1482 : void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
429 : : {
430 : : /* "new" must be a freshly-initialized lock */
431 [ - + ]: 1482 : WARN_ON_ONCE(new->fl_ops);
432 : :
433 : 1482 : locks_copy_conflock(new, fl);
434 : :
435 : 1482 : new->fl_file = fl->fl_file;
436 : 1482 : new->fl_ops = fl->fl_ops;
437 : :
438 [ - + ]: 1482 : if (fl->fl_ops) {
439 [ # # ]: 0 : if (fl->fl_ops->fl_copy_lock)
440 : 0 : fl->fl_ops->fl_copy_lock(new, fl);
441 : : }
442 : 1482 : }
443 : : EXPORT_SYMBOL(locks_copy_lock);
444 : :
445 : 1482 : static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
446 : : {
447 : 1482 : struct file_lock *f;
448 : :
449 : : /*
450 : : * As ctx->flc_lock is held, new requests cannot be added to
451 : : * ->fl_blocked_requests, so we don't need a lock to check if it
452 : : * is empty.
453 : : */
454 [ - + ]: 1482 : if (list_empty(&fl->fl_blocked_requests))
455 : : return;
456 : 0 : spin_lock(&blocked_lock_lock);
457 [ # # ]: 0 : list_splice_init(&fl->fl_blocked_requests, &new->fl_blocked_requests);
458 [ # # ]: 0 : list_for_each_entry(f, &new->fl_blocked_requests, fl_blocked_member)
459 : 0 : f->fl_blocker = new;
460 : 0 : spin_unlock(&blocked_lock_lock);
461 : : }
462 : :
463 : 2886 : static inline int flock_translate_cmd(int cmd) {
464 : 2886 : if (cmd & LOCK_MAND)
465 : 0 : return cmd & (LOCK_MAND | LOCK_RW);
466 [ + - ]: 2886 : switch (cmd) {
467 : : case LOCK_SH:
468 : : return F_RDLCK;
469 : : case LOCK_EX:
470 : : return F_WRLCK;
471 : : case LOCK_UN:
472 : : return F_UNLCK;
473 : : }
474 : : return -EINVAL;
475 : : }
476 : :
477 : : /* Fill in a file_lock structure with an appropriate FLOCK lock. */
478 : : static struct file_lock *
479 : 2886 : flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
480 : : {
481 [ - + ]: 2886 : int type = flock_translate_cmd(cmd);
482 : :
483 [ - + ]: 2886 : if (type < 0)
484 : 0 : return ERR_PTR(type);
485 : :
486 [ + + ]: 2886 : if (fl == NULL) {
487 : 936 : fl = locks_alloc_lock();
488 [ + - ]: 936 : if (fl == NULL)
489 : : return ERR_PTR(-ENOMEM);
490 : : } else {
491 : 1950 : locks_init_lock(fl);
492 : : }
493 : :
494 : 2886 : fl->fl_file = filp;
495 : 2886 : fl->fl_owner = filp;
496 : 2886 : fl->fl_pid = current->tgid;
497 : 2886 : fl->fl_flags = FL_FLOCK;
498 : 2886 : fl->fl_type = type;
499 : 2886 : fl->fl_end = OFFSET_MAX;
500 : :
501 : 2886 : return fl;
502 : : }
503 : :
504 : 624 : static int assign_type(struct file_lock *fl, long type)
505 : : {
506 : 624 : switch (type) {
507 : 624 : case F_RDLCK:
508 : : case F_WRLCK:
509 : : case F_UNLCK:
510 : 624 : fl->fl_type = type;
511 : 624 : break;
512 : : default:
513 : : return -EINVAL;
514 : : }
515 : 624 : return 0;
516 : : }
517 : :
518 : 624 : static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
519 : : struct flock64 *l)
520 : : {
521 [ + - - - ]: 624 : switch (l->l_whence) {
522 : 624 : case SEEK_SET:
523 : 624 : fl->fl_start = 0;
524 : 624 : break;
525 : 0 : case SEEK_CUR:
526 : 0 : fl->fl_start = filp->f_pos;
527 : 0 : break;
528 : 0 : case SEEK_END:
529 : 0 : fl->fl_start = i_size_read(file_inode(filp));
530 : 0 : break;
531 : : default:
532 : : return -EINVAL;
533 : : }
534 [ + - ]: 624 : if (l->l_start > OFFSET_MAX - fl->fl_start)
535 : : return -EOVERFLOW;
536 : 624 : fl->fl_start += l->l_start;
537 [ + - ]: 624 : if (fl->fl_start < 0)
538 : : return -EINVAL;
539 : :
540 : : /* POSIX-1996 leaves the case l->l_len < 0 undefined;
541 : : POSIX-2001 defines it. */
542 [ - + ]: 624 : if (l->l_len > 0) {
543 [ # # ]: 0 : if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
544 : : return -EOVERFLOW;
545 : 0 : fl->fl_end = fl->fl_start + l->l_len - 1;
546 : :
547 [ - + ]: 624 : } else if (l->l_len < 0) {
548 [ # # ]: 0 : if (fl->fl_start + l->l_len < 0)
549 : : return -EINVAL;
550 : 0 : fl->fl_end = fl->fl_start - 1;
551 : 0 : fl->fl_start += l->l_len;
552 : : } else
553 : 624 : fl->fl_end = OFFSET_MAX;
554 : :
555 [ + - ]: 624 : fl->fl_owner = current->files;
556 : 624 : fl->fl_pid = current->tgid;
557 : 624 : fl->fl_file = filp;
558 : 624 : fl->fl_flags = FL_POSIX;
559 : 624 : fl->fl_ops = NULL;
560 : 624 : fl->fl_lmops = NULL;
561 : :
562 [ + - ]: 624 : return assign_type(fl, l->l_type);
563 : : }
564 : :
565 : : /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
566 : : * style lock.
567 : : */
568 : 624 : static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
569 : : struct flock *l)
570 : : {
571 : 624 : struct flock64 ll = {
572 : 624 : .l_type = l->l_type,
573 : 624 : .l_whence = l->l_whence,
574 : 624 : .l_start = l->l_start,
575 : 624 : .l_len = l->l_len,
576 : : };
577 : :
578 : 624 : return flock64_to_posix_lock(filp, fl, &ll);
579 : : }
580 : :
581 : : /* default lease lock manager operations */
582 : : static bool
583 : 0 : lease_break_callback(struct file_lock *fl)
584 : : {
585 : 0 : kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
586 : 0 : return false;
587 : : }
588 : :
589 : : static void
590 : 0 : lease_setup(struct file_lock *fl, void **priv)
591 : : {
592 : 0 : struct file *filp = fl->fl_file;
593 : 0 : struct fasync_struct *fa = *priv;
594 : :
595 : : /*
596 : : * fasync_insert_entry() returns the old entry if any. If there was no
597 : : * old entry, then it used "priv" and inserted it into the fasync list.
598 : : * Clear the pointer to indicate that it shouldn't be freed.
599 : : */
600 [ # # ]: 0 : if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
601 : 0 : *priv = NULL;
602 : :
603 : 0 : __f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
604 : 0 : }
605 : :
606 : : static const struct lock_manager_operations lease_manager_ops = {
607 : : .lm_break = lease_break_callback,
608 : : .lm_change = lease_modify,
609 : : .lm_setup = lease_setup,
610 : : };
611 : :
612 : : /*
613 : : * Initialize a lease, use the default lock manager operations
614 : : */
615 : 0 : static int lease_init(struct file *filp, long type, struct file_lock *fl)
616 : : {
617 : 0 : if (assign_type(fl, type) != 0)
618 : : return -EINVAL;
619 : :
620 : 0 : fl->fl_owner = filp;
621 : 0 : fl->fl_pid = current->tgid;
622 : :
623 : 0 : fl->fl_file = filp;
624 : 0 : fl->fl_flags = FL_LEASE;
625 : 0 : fl->fl_start = 0;
626 : 0 : fl->fl_end = OFFSET_MAX;
627 : 0 : fl->fl_ops = NULL;
628 : 0 : fl->fl_lmops = &lease_manager_ops;
629 : 0 : return 0;
630 : : }
631 : :
632 : : /* Allocate a file_lock initialised to this type of lease */
633 : 0 : static struct file_lock *lease_alloc(struct file *filp, long type)
634 : : {
635 : 0 : struct file_lock *fl = locks_alloc_lock();
636 : 0 : int error = -ENOMEM;
637 : :
638 [ # # ]: 0 : if (fl == NULL)
639 : : return ERR_PTR(error);
640 : :
641 [ # # ]: 0 : error = lease_init(filp, type, fl);
642 : 0 : if (error) {
643 : 0 : locks_free_lock(fl);
644 : 0 : return ERR_PTR(error);
645 : : }
646 : : return fl;
647 : : }
648 : :
649 : : /* Check if two locks overlap each other.
650 : : */
651 : 0 : static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
652 : : {
653 : 0 : return ((fl1->fl_end >= fl2->fl_start) &&
654 [ # # # # : 0 : (fl2->fl_end >= fl1->fl_start));
# # ]
655 : : }
656 : :
657 : : /*
658 : : * Check whether two locks have the same owner.
659 : : */
660 : 1404 : static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
661 : : {
662 : 1404 : return fl1->fl_owner == fl2->fl_owner;
663 : : }
664 : :
665 : : /* Must be called with the flc_lock held! */
666 : 1482 : static void locks_insert_global_locks(struct file_lock *fl)
667 : : {
668 : 1482 : struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
669 : :
670 : 1482 : percpu_rwsem_assert_held(&file_rwsem);
671 : :
672 : 1482 : spin_lock(&fll->lock);
673 [ + + ]: 1482 : fl->fl_link_cpu = smp_processor_id();
674 [ + + ]: 1482 : hlist_add_head(&fl->fl_link, &fll->hlist);
675 : 1482 : spin_unlock(&fll->lock);
676 : 1482 : }
677 : :
678 : : /* Must be called with the flc_lock held! */
679 : 1404 : static void locks_delete_global_locks(struct file_lock *fl)
680 : : {
681 : 1404 : struct file_lock_list_struct *fll;
682 : :
683 : 1404 : percpu_rwsem_assert_held(&file_rwsem);
684 : :
685 : : /*
686 : : * Avoid taking lock if already unhashed. This is safe since this check
687 : : * is done while holding the flc_lock, and new insertions into the list
688 : : * also require that it be held.
689 : : */
690 [ + - ]: 1404 : if (hlist_unhashed(&fl->fl_link))
691 : : return;
692 : :
693 : 1404 : fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
694 : 1404 : spin_lock(&fll->lock);
695 [ + - ]: 1404 : hlist_del_init(&fl->fl_link);
696 : 1404 : spin_unlock(&fll->lock);
697 : : }
698 : :
699 : : static unsigned long
700 : 0 : posix_owner_key(struct file_lock *fl)
701 : : {
702 : 0 : return (unsigned long)fl->fl_owner;
703 : : }
704 : :
705 : 0 : static void locks_insert_global_blocked(struct file_lock *waiter)
706 : : {
707 : 0 : lockdep_assert_held(&blocked_lock_lock);
708 : :
709 : 0 : hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
710 : 0 : }
711 : :
712 : 0 : static void locks_delete_global_blocked(struct file_lock *waiter)
713 : : {
714 : 0 : lockdep_assert_held(&blocked_lock_lock);
715 : :
716 : 0 : hash_del(&waiter->fl_link);
717 : : }
718 : :
719 : : /* Remove waiter from blocker's block list.
720 : : * When blocker ends up pointing to itself then the list is empty.
721 : : *
722 : : * Must be called with blocked_lock_lock held.
723 : : */
724 : 0 : static void __locks_delete_block(struct file_lock *waiter)
725 : : {
726 : 0 : locks_delete_global_blocked(waiter);
727 [ # # ]: 0 : list_del_init(&waiter->fl_blocked_member);
728 : : }
729 : :
730 : 0 : static void __locks_wake_up_blocks(struct file_lock *blocker)
731 : : {
732 : 0 : while (!list_empty(&blocker->fl_blocked_requests)) {
733 : 0 : struct file_lock *waiter;
734 : :
735 : 0 : waiter = list_first_entry(&blocker->fl_blocked_requests,
736 : : struct file_lock, fl_blocked_member);
737 [ # # ]: 0 : __locks_delete_block(waiter);
738 [ # # # # ]: 0 : if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
739 : 0 : waiter->fl_lmops->lm_notify(waiter);
740 : : else
741 : 0 : wake_up(&waiter->fl_wait);
742 : :
743 : : /*
744 : : * The setting of fl_blocker to NULL marks the "done"
745 : : * point in deleting a block. Paired with acquire at the top
746 : : * of locks_delete_block().
747 : : */
748 [ # # ]: 0 : smp_store_release(&waiter->fl_blocker, NULL);
749 : : }
750 : 0 : }
751 : :
752 : : /**
753 : : * locks_delete_lock - stop waiting for a file lock
754 : : * @waiter: the lock which was waiting
755 : : *
756 : : * lockd/nfsd need to disconnect the lock while working on it.
757 : : */
758 : 1560 : int locks_delete_block(struct file_lock *waiter)
759 : : {
760 : 1560 : int status = -ENOENT;
761 : :
762 : : /*
763 : : * If fl_blocker is NULL, it won't be set again as this thread "owns"
764 : : * the lock and is the only one that might try to claim the lock.
765 : : *
766 : : * We use acquire/release to manage fl_blocker so that we can
767 : : * optimize away taking the blocked_lock_lock in many cases.
768 : : *
769 : : * The smp_load_acquire guarantees two things:
770 : : *
771 : : * 1/ that fl_blocked_requests can be tested locklessly. If something
772 : : * was recently added to that list it must have been in a locked region
773 : : * *before* the locked region when fl_blocker was set to NULL.
774 : : *
775 : : * 2/ that no other thread is accessing 'waiter', so it is safe to free
776 : : * it. __locks_wake_up_blocks is careful not to touch waiter after
777 : : * fl_blocker is released.
778 : : *
779 : : * If a lockless check of fl_blocker shows it to be NULL, we know that
780 : : * no new locks can be inserted into its fl_blocked_requests list, and
781 : : * can avoid doing anything further if the list is empty.
782 : : */
783 [ + - - + ]: 1560 : if (!smp_load_acquire(&waiter->fl_blocker) &&
784 [ - + ]: 1560 : list_empty(&waiter->fl_blocked_requests))
785 : : return status;
786 : :
787 : 0 : spin_lock(&blocked_lock_lock);
788 [ # # ]: 0 : if (waiter->fl_blocker)
789 : 0 : status = 0;
790 : 0 : __locks_wake_up_blocks(waiter);
791 [ # # ]: 0 : __locks_delete_block(waiter);
792 : :
793 : : /*
794 : : * The setting of fl_blocker to NULL marks the "done" point in deleting
795 : : * a block. Paired with acquire at the top of this function.
796 : : */
797 : 0 : smp_store_release(&waiter->fl_blocker, NULL);
798 : 0 : spin_unlock(&blocked_lock_lock);
799 : 0 : return status;
800 : : }
801 : : EXPORT_SYMBOL(locks_delete_block);
802 : :
803 : : /* Insert waiter into blocker's block list.
804 : : * We use a circular list so that processes can be easily woken up in
805 : : * the order they blocked. The documentation doesn't require this but
806 : : * it seems like the reasonable thing to do.
807 : : *
808 : : * Must be called with both the flc_lock and blocked_lock_lock held. The
809 : : * fl_blocked_requests list itself is protected by the blocked_lock_lock,
810 : : * but by ensuring that the flc_lock is also held on insertions we can avoid
811 : : * taking the blocked_lock_lock in some cases when we see that the
812 : : * fl_blocked_requests list is empty.
813 : : *
814 : : * Rather than just adding to the list, we check for conflicts with any existing
815 : : * waiters, and add beneath any waiter that blocks the new waiter.
816 : : * Thus wakeups don't happen until needed.
817 : : */
818 : 0 : static void __locks_insert_block(struct file_lock *blocker,
819 : : struct file_lock *waiter,
820 : : bool conflict(struct file_lock *,
821 : : struct file_lock *))
822 : : {
823 : 0 : struct file_lock *fl;
824 [ # # ]: 0 : BUG_ON(!list_empty(&waiter->fl_blocked_member));
825 : :
826 : 0 : new_blocker:
827 [ # # ]: 0 : list_for_each_entry(fl, &blocker->fl_blocked_requests, fl_blocked_member)
828 [ # # ]: 0 : if (conflict(fl, waiter)) {
829 : 0 : blocker = fl;
830 : 0 : goto new_blocker;
831 : : }
832 : 0 : waiter->fl_blocker = blocker;
833 [ # # ]: 0 : list_add_tail(&waiter->fl_blocked_member, &blocker->fl_blocked_requests);
834 [ # # ]: 0 : if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
835 [ # # ]: 0 : locks_insert_global_blocked(waiter);
836 : :
837 : : /* The requests in waiter->fl_blocked are known to conflict with
838 : : * waiter, but might not conflict with blocker, or the requests
839 : : * and lock which block it. So they all need to be woken.
840 : : */
841 : 0 : __locks_wake_up_blocks(waiter);
842 : 0 : }
843 : :
844 : : /* Must be called with flc_lock held. */
845 : 0 : static void locks_insert_block(struct file_lock *blocker,
846 : : struct file_lock *waiter,
847 : : bool conflict(struct file_lock *,
848 : : struct file_lock *))
849 : : {
850 : 0 : spin_lock(&blocked_lock_lock);
851 : 0 : __locks_insert_block(blocker, waiter, conflict);
852 : 0 : spin_unlock(&blocked_lock_lock);
853 : 0 : }
854 : :
855 : : /*
856 : : * Wake up processes blocked waiting for blocker.
857 : : *
858 : : * Must be called with the inode->flc_lock held!
859 : : */
860 : 1404 : static void locks_wake_up_blocks(struct file_lock *blocker)
861 : : {
862 : : /*
863 : : * Avoid taking global lock if list is empty. This is safe since new
864 : : * blocked requests are only added to the list under the flc_lock, and
865 : : * the flc_lock is always held here. Note that removal from the
866 : : * fl_blocked_requests list does not require the flc_lock, so we must
867 : : * recheck list_empty() after acquiring the blocked_lock_lock.
868 : : */
869 [ - + ]: 1404 : if (list_empty(&blocker->fl_blocked_requests))
870 : : return;
871 : :
872 : 0 : spin_lock(&blocked_lock_lock);
873 : 0 : __locks_wake_up_blocks(blocker);
874 : 0 : spin_unlock(&blocked_lock_lock);
875 : : }
876 : :
877 : : static void
878 : 1482 : locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
879 : : {
880 : 1482 : list_add_tail(&fl->fl_list, before);
881 : 0 : locks_insert_global_locks(fl);
882 : 0 : }
883 : :
884 : : static void
885 : 1404 : locks_unlink_lock_ctx(struct file_lock *fl)
886 : : {
887 : 1404 : locks_delete_global_locks(fl);
888 : 1404 : list_del_init(&fl->fl_list);
889 : 1404 : locks_wake_up_blocks(fl);
890 : 1404 : }
891 : :
892 : : static void
893 : 1404 : locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
894 : : {
895 : 0 : locks_unlink_lock_ctx(fl);
896 [ # # ]: 0 : if (dispose)
897 : 1404 : list_add(&fl->fl_list, dispose);
898 : : else
899 : 0 : locks_free_lock(fl);
900 : 0 : }
901 : :
902 : : /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
903 : : * checks for shared/exclusive status of overlapping locks.
904 : : */
905 : 0 : static bool locks_conflict(struct file_lock *caller_fl,
906 : : struct file_lock *sys_fl)
907 : : {
908 : 0 : if (sys_fl->fl_type == F_WRLCK)
909 : : return true;
910 [ # # # # : 0 : if (caller_fl->fl_type == F_WRLCK)
# # # # #
# # # ]
911 : 0 : return true;
912 : : return false;
913 : : }
914 : :
915 : : /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
916 : : * checking before calling the locks_conflict().
917 : : */
918 : 0 : static bool posix_locks_conflict(struct file_lock *caller_fl,
919 : : struct file_lock *sys_fl)
920 : : {
921 : : /* POSIX locks owned by the same process do not conflict with
922 : : * each other.
923 : : */
924 [ # # ]: 0 : if (posix_same_owner(caller_fl, sys_fl))
925 : : return false;
926 : :
927 : : /* Check whether they overlap */
928 [ # # # # : 0 : if (!locks_overlap(caller_fl, sys_fl))
# # ]
929 : : return false;
930 : :
931 [ # # # # : 0 : return locks_conflict(caller_fl, sys_fl);
# # ]
932 : : }
933 : :
934 : : /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
935 : : * checking before calling the locks_conflict().
936 : : */
937 : 0 : static bool flock_locks_conflict(struct file_lock *caller_fl,
938 : : struct file_lock *sys_fl)
939 : : {
940 : : /* FLOCK locks referring to the same filp do not conflict with
941 : : * each other.
942 : : */
943 [ # # ]: 0 : if (caller_fl->fl_file == sys_fl->fl_file)
944 : : return false;
945 [ # # # # : 0 : if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
# # # # ]
946 : : return false;
947 : :
948 [ # # # # ]: 0 : return locks_conflict(caller_fl, sys_fl);
949 : : }
950 : :
951 : : void
952 : 0 : posix_test_lock(struct file *filp, struct file_lock *fl)
953 : : {
954 : 0 : struct file_lock *cfl;
955 : 0 : struct file_lock_context *ctx;
956 : 0 : struct inode *inode = locks_inode(filp);
957 : :
958 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
959 [ # # # # ]: 0 : if (!ctx || list_empty_careful(&ctx->flc_posix)) {
960 : 0 : fl->fl_type = F_UNLCK;
961 : 0 : return;
962 : : }
963 : :
964 : 0 : spin_lock(&ctx->flc_lock);
965 [ # # ]: 0 : list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
966 [ # # ]: 0 : if (posix_locks_conflict(fl, cfl)) {
967 : 0 : locks_copy_conflock(fl, cfl);
968 : 0 : goto out;
969 : : }
970 : : }
971 : 0 : fl->fl_type = F_UNLCK;
972 : 0 : out:
973 : 0 : spin_unlock(&ctx->flc_lock);
974 : : return;
975 : : }
976 : : EXPORT_SYMBOL(posix_test_lock);
977 : :
978 : : /*
979 : : * Deadlock detection:
980 : : *
981 : : * We attempt to detect deadlocks that are due purely to posix file
982 : : * locks.
983 : : *
984 : : * We assume that a task can be waiting for at most one lock at a time.
985 : : * So for any acquired lock, the process holding that lock may be
986 : : * waiting on at most one other lock. That lock in turns may be held by
987 : : * someone waiting for at most one other lock. Given a requested lock
988 : : * caller_fl which is about to wait for a conflicting lock block_fl, we
989 : : * follow this chain of waiters to ensure we are not about to create a
990 : : * cycle.
991 : : *
992 : : * Since we do this before we ever put a process to sleep on a lock, we
993 : : * are ensured that there is never a cycle; that is what guarantees that
994 : : * the while() loop in posix_locks_deadlock() eventually completes.
995 : : *
996 : : * Note: the above assumption may not be true when handling lock
997 : : * requests from a broken NFS client. It may also fail in the presence
998 : : * of tasks (such as posix threads) sharing the same open file table.
999 : : * To handle those cases, we just bail out after a few iterations.
1000 : : *
1001 : : * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
1002 : : * Because the owner is not even nominally tied to a thread of
1003 : : * execution, the deadlock detection below can't reasonably work well. Just
1004 : : * skip it for those.
1005 : : *
1006 : : * In principle, we could do a more limited deadlock detection on FL_OFDLCK
1007 : : * locks that just checks for the case where two tasks are attempting to
1008 : : * upgrade from read to write locks on the same inode.
1009 : : */
1010 : :
1011 : : #define MAX_DEADLK_ITERATIONS 10
1012 : :
1013 : : /* Find a lock that the owner of the given block_fl is blocking on. */
1014 : 0 : static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
1015 : : {
1016 : 0 : struct file_lock *fl;
1017 : :
1018 [ # # # # : 0 : hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
# # ]
1019 [ # # ]: 0 : if (posix_same_owner(fl, block_fl)) {
1020 [ # # ]: 0 : while (fl->fl_blocker)
1021 : : fl = fl->fl_blocker;
1022 : 0 : return fl;
1023 : : }
1024 : : }
1025 : : return NULL;
1026 : : }
1027 : :
1028 : : /* Must be called with the blocked_lock_lock held! */
1029 : 0 : static int posix_locks_deadlock(struct file_lock *caller_fl,
1030 : : struct file_lock *block_fl)
1031 : : {
1032 : 0 : int i = 0;
1033 : :
1034 : 0 : lockdep_assert_held(&blocked_lock_lock);
1035 : :
1036 : : /*
1037 : : * This deadlock detector can't reasonably detect deadlocks with
1038 : : * FL_OFDLCK locks, since they aren't owned by a process, per-se.
1039 : : */
1040 [ # # ]: 0 : if (IS_OFDLCK(caller_fl))
1041 : : return 0;
1042 : :
1043 [ # # ]: 0 : while ((block_fl = what_owner_is_waiting_for(block_fl))) {
1044 [ # # ]: 0 : if (i++ > MAX_DEADLK_ITERATIONS)
1045 : : return 0;
1046 [ # # ]: 0 : if (posix_same_owner(caller_fl, block_fl))
1047 : : return 1;
1048 : : }
1049 : : return 0;
1050 : : }
1051 : :
1052 : : /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
1053 : : * after any leases, but before any posix locks.
1054 : : *
1055 : : * Note that if called with an FL_EXISTS argument, the caller may determine
1056 : : * whether or not a lock was successfully freed by testing the return
1057 : : * value for -ENOENT.
1058 : : */
1059 : 2886 : static int flock_lock_inode(struct inode *inode, struct file_lock *request)
1060 : : {
1061 : 2886 : struct file_lock *new_fl = NULL;
1062 : 2886 : struct file_lock *fl;
1063 : 2886 : struct file_lock_context *ctx;
1064 : 2886 : int error = 0;
1065 : 2886 : bool found = false;
1066 : 2886 : LIST_HEAD(dispose);
1067 : :
1068 : 2886 : ctx = locks_get_lock_context(inode, request->fl_type);
1069 [ - + ]: 2886 : if (!ctx) {
1070 [ # # ]: 0 : if (request->fl_type != F_UNLCK)
1071 : : return -ENOMEM;
1072 [ # # ]: 0 : return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
1073 : : }
1074 : :
1075 [ + - + + ]: 2886 : if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
1076 : 936 : new_fl = locks_alloc_lock();
1077 [ + - ]: 936 : if (!new_fl)
1078 : : return -ENOMEM;
1079 : : }
1080 : :
1081 : 2886 : percpu_down_read(&file_rwsem);
1082 : 2886 : spin_lock(&ctx->flc_lock);
1083 [ - + ]: 2886 : if (request->fl_flags & FL_ACCESS)
1084 : 0 : goto find_conflict;
1085 : :
1086 [ + + ]: 3978 : list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
1087 [ + + ]: 1950 : if (request->fl_file != fl->fl_file)
1088 : 1092 : continue;
1089 [ - + ]: 858 : if (request->fl_type == fl->fl_type)
1090 : 0 : goto out;
1091 : 858 : found = true;
1092 : 858 : locks_delete_lock_ctx(fl, &dispose);
1093 : : break;
1094 : : }
1095 : :
1096 [ + + ]: 2886 : if (request->fl_type == F_UNLCK) {
1097 [ - + - - ]: 1950 : if ((request->fl_flags & FL_EXISTS) && !found)
1098 : 0 : error = -ENOENT;
1099 : 1950 : goto out;
1100 : : }
1101 : :
1102 : 936 : find_conflict:
1103 [ - + ]: 936 : list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
1104 [ # # ]: 0 : if (!flock_locks_conflict(request, fl))
1105 : 0 : continue;
1106 : 0 : error = -EAGAIN;
1107 [ # # ]: 0 : if (!(request->fl_flags & FL_SLEEP))
1108 : 0 : goto out;
1109 : 0 : error = FILE_LOCK_DEFERRED;
1110 : 0 : locks_insert_block(fl, request, flock_locks_conflict);
1111 : 0 : goto out;
1112 : : }
1113 [ - + ]: 936 : if (request->fl_flags & FL_ACCESS)
1114 : 0 : goto out;
1115 : 936 : locks_copy_lock(new_fl, request);
1116 : 936 : locks_move_blocks(new_fl, request);
1117 : 936 : locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
1118 : 936 : new_fl = NULL;
1119 : 936 : error = 0;
1120 : :
1121 : 2886 : out:
1122 : 2886 : spin_unlock(&ctx->flc_lock);
1123 : 2886 : percpu_up_read(&file_rwsem);
1124 [ - + ]: 2886 : if (new_fl)
1125 : 0 : locks_free_lock(new_fl);
1126 : 2886 : locks_dispose_list(&dispose);
1127 : 2886 : trace_flock_lock_inode(inode, request, error);
1128 : 2886 : return error;
1129 : : }
1130 : :
1131 : 1404 : static int posix_lock_inode(struct inode *inode, struct file_lock *request,
1132 : : struct file_lock *conflock)
1133 : : {
1134 : 1404 : struct file_lock *fl, *tmp;
1135 : 1404 : struct file_lock *new_fl = NULL;
1136 : 1404 : struct file_lock *new_fl2 = NULL;
1137 : 1404 : struct file_lock *left = NULL;
1138 : 1404 : struct file_lock *right = NULL;
1139 : 1404 : struct file_lock_context *ctx;
1140 : 1404 : int error;
1141 : 1404 : bool added = false;
1142 : 1404 : LIST_HEAD(dispose);
1143 : :
1144 : 1404 : ctx = locks_get_lock_context(inode, request->fl_type);
1145 [ - + ]: 1404 : if (!ctx)
1146 [ # # ]: 0 : return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
1147 : :
1148 : : /*
1149 : : * We may need two file_lock structures for this operation,
1150 : : * so we get them in advance to avoid races.
1151 : : *
1152 : : * In some cases we can be sure, that no new locks will be needed
1153 : : */
1154 [ + - ]: 1404 : if (!(request->fl_flags & FL_ACCESS) &&
1155 [ + + ]: 1404 : (request->fl_type != F_UNLCK ||
1156 [ + - - + ]: 858 : request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1157 : 546 : new_fl = locks_alloc_lock();
1158 : 546 : new_fl2 = locks_alloc_lock();
1159 : : }
1160 : :
1161 : 1404 : percpu_down_read(&file_rwsem);
1162 : 1404 : spin_lock(&ctx->flc_lock);
1163 : : /*
1164 : : * New lock request. Walk all POSIX locks and look for conflicts. If
1165 : : * there are any, either return error or put the request on the
1166 : : * blocker's list of waiters and the global blocked_hash.
1167 : : */
1168 [ + + ]: 1404 : if (request->fl_type != F_UNLCK) {
1169 [ - + ]: 546 : list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1170 [ # # ]: 0 : if (!posix_locks_conflict(request, fl))
1171 : 0 : continue;
1172 [ # # ]: 0 : if (conflock)
1173 : 0 : locks_copy_conflock(conflock, fl);
1174 : 0 : error = -EAGAIN;
1175 [ # # ]: 0 : if (!(request->fl_flags & FL_SLEEP))
1176 : 0 : goto out;
1177 : : /*
1178 : : * Deadlock detection and insertion into the blocked
1179 : : * locks list must be done while holding the same lock!
1180 : : */
1181 : 0 : error = -EDEADLK;
1182 : 0 : spin_lock(&blocked_lock_lock);
1183 : : /*
1184 : : * Ensure that we don't find any locks blocked on this
1185 : : * request during deadlock detection.
1186 : : */
1187 : 0 : __locks_wake_up_blocks(request);
1188 [ # # ]: 0 : if (likely(!posix_locks_deadlock(request, fl))) {
1189 : 0 : error = FILE_LOCK_DEFERRED;
1190 : 0 : __locks_insert_block(fl, request,
1191 : : posix_locks_conflict);
1192 : : }
1193 : 0 : spin_unlock(&blocked_lock_lock);
1194 : 0 : goto out;
1195 : : }
1196 : : }
1197 : :
1198 : : /* If we're just looking for a conflict, we're done. */
1199 : 1404 : error = 0;
1200 [ - + ]: 1404 : if (request->fl_flags & FL_ACCESS)
1201 : 0 : goto out;
1202 : :
1203 : : /* Find the first old lock with the same owner as the new lock */
1204 [ + + ]: 1716 : list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1205 [ + + ]: 858 : if (posix_same_owner(request, fl))
1206 : : break;
1207 : : }
1208 : :
1209 : : /* Process locks with this owner. */
1210 [ + + ]: 1950 : list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1211 [ + - ]: 546 : if (!posix_same_owner(request, fl))
1212 : : break;
1213 : :
1214 : : /* Detect adjacent or overlapping regions (if same lock type) */
1215 [ - + ]: 546 : if (request->fl_type == fl->fl_type) {
1216 : : /* In all comparisons of start vs end, use
1217 : : * "start - 1" rather than "end + 1". If end
1218 : : * is OFFSET_MAX, end + 1 will become negative.
1219 : : */
1220 [ # # ]: 0 : if (fl->fl_end < request->fl_start - 1)
1221 : 0 : continue;
1222 : : /* If the next lock in the list has entirely bigger
1223 : : * addresses than the new one, insert the lock here.
1224 : : */
1225 [ # # ]: 0 : if (fl->fl_start - 1 > request->fl_end)
1226 : : break;
1227 : :
1228 : : /* If we come here, the new and old lock are of the
1229 : : * same type and adjacent or overlapping. Make one
1230 : : * lock yielding from the lower start address of both
1231 : : * locks to the higher end address.
1232 : : */
1233 [ # # ]: 0 : if (fl->fl_start > request->fl_start)
1234 : 0 : fl->fl_start = request->fl_start;
1235 : : else
1236 : 0 : request->fl_start = fl->fl_start;
1237 [ # # ]: 0 : if (fl->fl_end < request->fl_end)
1238 : 0 : fl->fl_end = request->fl_end;
1239 : : else
1240 : 0 : request->fl_end = fl->fl_end;
1241 [ # # ]: 0 : if (added) {
1242 : 0 : locks_delete_lock_ctx(fl, &dispose);
1243 : 0 : continue;
1244 : : }
1245 : : request = fl;
1246 : : added = true;
1247 : : } else {
1248 : : /* Processing for different lock types is a bit
1249 : : * more complex.
1250 : : */
1251 [ - + ]: 546 : if (fl->fl_end < request->fl_start)
1252 : 0 : continue;
1253 [ + - ]: 546 : if (fl->fl_start > request->fl_end)
1254 : : break;
1255 [ + - ]: 546 : if (request->fl_type == F_UNLCK)
1256 : 546 : added = true;
1257 [ - + ]: 546 : if (fl->fl_start < request->fl_start)
1258 : 0 : left = fl;
1259 : : /* If the next lock in the list has a higher end
1260 : : * address than the new one, insert the new one here.
1261 : : */
1262 [ + - ]: 546 : if (fl->fl_end > request->fl_end) {
1263 : : right = fl;
1264 : : break;
1265 : : }
1266 [ + - ]: 546 : if (fl->fl_start >= request->fl_start) {
1267 : : /* The new lock completely replaces an old
1268 : : * one (This may happen several times).
1269 : : */
1270 [ + - ]: 546 : if (added) {
1271 : 546 : locks_delete_lock_ctx(fl, &dispose);
1272 : 546 : continue;
1273 : : }
1274 : : /*
1275 : : * Replace the old lock with new_fl, and
1276 : : * remove the old one. It's safe to do the
1277 : : * insert here since we know that we won't be
1278 : : * using new_fl later, and that the lock is
1279 : : * just replacing an existing lock.
1280 : : */
1281 : 0 : error = -ENOLCK;
1282 [ # # ]: 0 : if (!new_fl)
1283 : 0 : goto out;
1284 : 0 : locks_copy_lock(new_fl, request);
1285 : 0 : request = new_fl;
1286 : 0 : new_fl = NULL;
1287 : 0 : locks_insert_lock_ctx(request, &fl->fl_list);
1288 : 0 : locks_delete_lock_ctx(fl, &dispose);
1289 : 0 : added = true;
1290 : : }
1291 : : }
1292 : : }
1293 : :
1294 : : /*
1295 : : * The above code only modifies existing locks in case of merging or
1296 : : * replacing. If new lock(s) need to be inserted all modifications are
1297 : : * done below this, so it's safe yet to bail out.
1298 : : */
1299 : 1404 : error = -ENOLCK; /* "no luck" */
1300 [ - + - - ]: 1404 : if (right && left == right && !new_fl2)
1301 : 0 : goto out;
1302 : :
1303 : 1404 : error = 0;
1304 [ + + ]: 1404 : if (!added) {
1305 [ + + ]: 858 : if (request->fl_type == F_UNLCK) {
1306 [ - + ]: 312 : if (request->fl_flags & FL_EXISTS)
1307 : 0 : error = -ENOENT;
1308 : 312 : goto out;
1309 : : }
1310 : :
1311 [ - + ]: 546 : if (!new_fl) {
1312 : 0 : error = -ENOLCK;
1313 : 0 : goto out;
1314 : : }
1315 : 546 : locks_copy_lock(new_fl, request);
1316 : 546 : locks_move_blocks(new_fl, request);
1317 : 546 : locks_insert_lock_ctx(new_fl, &fl->fl_list);
1318 : 546 : fl = new_fl;
1319 : 546 : new_fl = NULL;
1320 : : }
1321 [ - + ]: 1092 : if (right) {
1322 [ # # ]: 0 : if (left == right) {
1323 : : /* The new lock breaks the old one in two pieces,
1324 : : * so we have to use the second new lock.
1325 : : */
1326 : 0 : left = new_fl2;
1327 : 0 : new_fl2 = NULL;
1328 : 0 : locks_copy_lock(left, right);
1329 : 0 : locks_insert_lock_ctx(left, &fl->fl_list);
1330 : : }
1331 : 0 : right->fl_start = request->fl_end + 1;
1332 : 0 : locks_wake_up_blocks(right);
1333 : : }
1334 [ + - ]: 1092 : if (left) {
1335 : 0 : left->fl_end = request->fl_start - 1;
1336 : 0 : locks_wake_up_blocks(left);
1337 : : }
1338 : 1092 : out:
1339 : 1404 : spin_unlock(&ctx->flc_lock);
1340 : 1404 : percpu_up_read(&file_rwsem);
1341 : : /*
1342 : : * Free any unused locks.
1343 : : */
1344 [ - + ]: 1404 : if (new_fl)
1345 : 0 : locks_free_lock(new_fl);
1346 [ + + ]: 1404 : if (new_fl2)
1347 : 546 : locks_free_lock(new_fl2);
1348 : 1404 : locks_dispose_list(&dispose);
1349 : 1404 : trace_posix_lock_inode(inode, request, error);
1350 : :
1351 : 1404 : return error;
1352 : : }
1353 : :
1354 : : /**
1355 : : * posix_lock_file - Apply a POSIX-style lock to a file
1356 : : * @filp: The file to apply the lock to
1357 : : * @fl: The lock to be applied
1358 : : * @conflock: Place to return a copy of the conflicting lock, if found.
1359 : : *
1360 : : * Add a POSIX style lock to a file.
1361 : : * We merge adjacent & overlapping locks whenever possible.
1362 : : * POSIX locks are sorted by owner task, then by starting address
1363 : : *
1364 : : * Note that if called with an FL_EXISTS argument, the caller may determine
1365 : : * whether or not a lock was successfully freed by testing the return
1366 : : * value for -ENOENT.
1367 : : */
1368 : 1404 : int posix_lock_file(struct file *filp, struct file_lock *fl,
1369 : : struct file_lock *conflock)
1370 : : {
1371 : 0 : return posix_lock_inode(locks_inode(filp), fl, conflock);
1372 : : }
1373 : : EXPORT_SYMBOL(posix_lock_file);
1374 : :
1375 : : /**
1376 : : * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1377 : : * @inode: inode of file to which lock request should be applied
1378 : : * @fl: The lock to be applied
1379 : : *
1380 : : * Apply a POSIX style lock request to an inode.
1381 : : */
1382 : 0 : static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1383 : : {
1384 : 0 : int error;
1385 : 0 : might_sleep ();
1386 : 0 : for (;;) {
1387 : 0 : error = posix_lock_inode(inode, fl, NULL);
1388 [ # # ]: 0 : if (error != FILE_LOCK_DEFERRED)
1389 : : break;
1390 [ # # # # : 0 : error = wait_event_interruptible(fl->fl_wait,
# # ]
1391 : : list_empty(&fl->fl_blocked_member));
1392 [ # # ]: 0 : if (error)
1393 : : break;
1394 : : }
1395 : 0 : locks_delete_block(fl);
1396 : 0 : return error;
1397 : : }
1398 : :
1399 : : #ifdef CONFIG_MANDATORY_FILE_LOCKING
1400 : : /**
1401 : : * locks_mandatory_locked - Check for an active lock
1402 : : * @file: the file to check
1403 : : *
1404 : : * Searches the inode's list of locks to find any POSIX locks which conflict.
1405 : : * This function is called from locks_verify_locked() only.
1406 : : */
1407 : 0 : int locks_mandatory_locked(struct file *file)
1408 : : {
1409 : 0 : int ret;
1410 : 0 : struct inode *inode = locks_inode(file);
1411 : 0 : struct file_lock_context *ctx;
1412 : 0 : struct file_lock *fl;
1413 : :
1414 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
1415 [ # # # # ]: 0 : if (!ctx || list_empty_careful(&ctx->flc_posix))
1416 : : return 0;
1417 : :
1418 : : /*
1419 : : * Search the lock list for this inode for any POSIX locks.
1420 : : */
1421 : 0 : spin_lock(&ctx->flc_lock);
1422 : 0 : ret = 0;
1423 [ # # ]: 0 : list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1424 [ # # # # ]: 0 : if (fl->fl_owner != current->files &&
1425 : : fl->fl_owner != file) {
1426 : : ret = -EAGAIN;
1427 : : break;
1428 : : }
1429 : : }
1430 : 0 : spin_unlock(&ctx->flc_lock);
1431 : 0 : return ret;
1432 : : }
1433 : :
1434 : : /**
1435 : : * locks_mandatory_area - Check for a conflicting lock
1436 : : * @inode: the file to check
1437 : : * @filp: how the file was opened (if it was)
1438 : : * @start: first byte in the file to check
1439 : : * @end: lastbyte in the file to check
1440 : : * @type: %F_WRLCK for a write lock, else %F_RDLCK
1441 : : *
1442 : : * Searches the inode's list of locks to find any POSIX locks which conflict.
1443 : : */
1444 : 0 : int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1445 : : loff_t end, unsigned char type)
1446 : : {
1447 : 0 : struct file_lock fl;
1448 : 0 : int error;
1449 : 0 : bool sleep = false;
1450 : :
1451 : 0 : locks_init_lock(&fl);
1452 [ # # ]: 0 : fl.fl_pid = current->tgid;
1453 : 0 : fl.fl_file = filp;
1454 : 0 : fl.fl_flags = FL_POSIX | FL_ACCESS;
1455 [ # # # # ]: 0 : if (filp && !(filp->f_flags & O_NONBLOCK))
1456 : 0 : sleep = true;
1457 : 0 : fl.fl_type = type;
1458 : 0 : fl.fl_start = start;
1459 : 0 : fl.fl_end = end;
1460 : :
1461 : 0 : for (;;) {
1462 [ # # ]: 0 : if (filp) {
1463 : 0 : fl.fl_owner = filp;
1464 : 0 : fl.fl_flags &= ~FL_SLEEP;
1465 : 0 : error = posix_lock_inode(inode, &fl, NULL);
1466 [ # # ]: 0 : if (!error)
1467 : : break;
1468 : : }
1469 : :
1470 [ # # ]: 0 : if (sleep)
1471 : 0 : fl.fl_flags |= FL_SLEEP;
1472 : 0 : fl.fl_owner = current->files;
1473 : 0 : error = posix_lock_inode(inode, &fl, NULL);
1474 [ # # ]: 0 : if (error != FILE_LOCK_DEFERRED)
1475 : : break;
1476 [ # # # # : 0 : error = wait_event_interruptible(fl.fl_wait,
# # ]
1477 : : list_empty(&fl.fl_blocked_member));
1478 [ # # ]: 0 : if (!error) {
1479 : : /*
1480 : : * If we've been sleeping someone might have
1481 : : * changed the permissions behind our back.
1482 : : */
1483 [ # # ]: 0 : if (__mandatory_lock(inode))
1484 : 0 : continue;
1485 : : }
1486 : :
1487 : : break;
1488 : : }
1489 : 0 : locks_delete_block(&fl);
1490 : :
1491 : 0 : return error;
1492 : : }
1493 : : EXPORT_SYMBOL(locks_mandatory_area);
1494 : : #endif /* CONFIG_MANDATORY_FILE_LOCKING */
1495 : :
1496 : 0 : static void lease_clear_pending(struct file_lock *fl, int arg)
1497 : : {
1498 : 0 : switch (arg) {
1499 : 0 : case F_UNLCK:
1500 : 0 : fl->fl_flags &= ~FL_UNLOCK_PENDING;
1501 : : /* fall through */
1502 : 0 : case F_RDLCK:
1503 : 0 : fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1504 : : }
1505 : : }
1506 : :
1507 : : /* We already had a lease on this file; just change its type */
1508 : 0 : int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
1509 : : {
1510 [ # # ]: 0 : int error = assign_type(fl, arg);
1511 : :
1512 : 0 : if (error)
1513 : : return error;
1514 [ # # # ]: 0 : lease_clear_pending(fl, arg);
1515 : 0 : locks_wake_up_blocks(fl);
1516 [ # # ]: 0 : if (arg == F_UNLCK) {
1517 : 0 : struct file *filp = fl->fl_file;
1518 : :
1519 : 0 : f_delown(filp);
1520 : 0 : filp->f_owner.signum = 0;
1521 : 0 : fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1522 [ # # ]: 0 : if (fl->fl_fasync != NULL) {
1523 : 0 : printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1524 : 0 : fl->fl_fasync = NULL;
1525 : : }
1526 : 0 : locks_delete_lock_ctx(fl, dispose);
1527 : : }
1528 : : return 0;
1529 : : }
1530 : : EXPORT_SYMBOL(lease_modify);
1531 : :
1532 : 0 : static bool past_time(unsigned long then)
1533 : : {
1534 : 0 : if (!then)
1535 : : /* 0 is a special value meaning "this never expires": */
1536 : : return false;
1537 [ # # # # ]: 0 : return time_after(jiffies, then);
1538 : : }
1539 : :
1540 : 0 : static void time_out_leases(struct inode *inode, struct list_head *dispose)
1541 : : {
1542 : 0 : struct file_lock_context *ctx = inode->i_flctx;
1543 : 0 : struct file_lock *fl, *tmp;
1544 : :
1545 : 0 : lockdep_assert_held(&ctx->flc_lock);
1546 : :
1547 [ # # ]: 0 : list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1548 : 0 : trace_time_out_leases(inode, fl);
1549 [ # # # # ]: 0 : if (past_time(fl->fl_downgrade_time))
1550 : 0 : lease_modify(fl, F_RDLCK, dispose);
1551 [ # # # # ]: 0 : if (past_time(fl->fl_break_time))
1552 : 0 : lease_modify(fl, F_UNLCK, dispose);
1553 : : }
1554 : 0 : }
1555 : :
1556 : 0 : static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1557 : : {
1558 : 0 : bool rc;
1559 : :
1560 [ # # ]: 0 : if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) {
1561 : 0 : rc = false;
1562 : 0 : goto trace;
1563 : : }
1564 [ # # # # ]: 0 : if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) {
1565 : 0 : rc = false;
1566 : 0 : goto trace;
1567 : : }
1568 : :
1569 [ # # ]: 0 : rc = locks_conflict(breaker, lease);
1570 : 0 : trace:
1571 : 0 : trace_leases_conflict(rc, lease, breaker);
1572 : 0 : return rc;
1573 : : }
1574 : :
1575 : : static bool
1576 : : any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1577 : : {
1578 : : struct file_lock_context *ctx = inode->i_flctx;
1579 : : struct file_lock *fl;
1580 : :
1581 : : lockdep_assert_held(&ctx->flc_lock);
1582 : :
1583 : : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1584 : : if (leases_conflict(fl, breaker))
1585 : : return true;
1586 : : }
1587 : : return false;
1588 : : }
1589 : :
1590 : : /**
1591 : : * __break_lease - revoke all outstanding leases on file
1592 : : * @inode: the inode of the file to return
1593 : : * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1594 : : * break all leases
1595 : : * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1596 : : * only delegations
1597 : : *
1598 : : * break_lease (inlined for speed) has checked there already is at least
1599 : : * some kind of lock (maybe a lease) on this file. Leases are broken on
1600 : : * a call to open() or truncate(). This function can sleep unless you
1601 : : * specified %O_NONBLOCK to your open().
1602 : : */
1603 : 0 : int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1604 : : {
1605 : 0 : int error = 0;
1606 : 0 : struct file_lock_context *ctx;
1607 : 0 : struct file_lock *new_fl, *fl, *tmp;
1608 : 0 : unsigned long break_time;
1609 : 0 : int want_write = (mode & O_ACCMODE) != O_RDONLY;
1610 : 0 : LIST_HEAD(dispose);
1611 : :
1612 : 0 : new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1613 [ # # ]: 0 : if (IS_ERR(new_fl))
1614 : 0 : return PTR_ERR(new_fl);
1615 : 0 : new_fl->fl_flags = type;
1616 : :
1617 : : /* typically we will check that ctx is non-NULL before calling */
1618 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
1619 [ # # ]: 0 : if (!ctx) {
1620 : 0 : WARN_ON_ONCE(1);
1621 : 0 : goto free_lock;
1622 : : }
1623 : :
1624 : 0 : percpu_down_read(&file_rwsem);
1625 : 0 : spin_lock(&ctx->flc_lock);
1626 : :
1627 : 0 : time_out_leases(inode, &dispose);
1628 : :
1629 [ # # ]: 0 : if (!any_leases_conflict(inode, new_fl))
1630 : 0 : goto out;
1631 : :
1632 : 0 : break_time = 0;
1633 [ # # ]: 0 : if (lease_break_time > 0) {
1634 : 0 : break_time = jiffies + lease_break_time * HZ;
1635 : 0 : if (break_time == 0)
1636 : : break_time++; /* so that 0 means no break time */
1637 : : }
1638 : :
1639 [ # # ]: 0 : list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1640 [ # # ]: 0 : if (!leases_conflict(fl, new_fl))
1641 : 0 : continue;
1642 [ # # ]: 0 : if (want_write) {
1643 [ # # ]: 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
1644 : 0 : continue;
1645 : 0 : fl->fl_flags |= FL_UNLOCK_PENDING;
1646 : 0 : fl->fl_break_time = break_time;
1647 : : } else {
1648 [ # # ]: 0 : if (lease_breaking(fl))
1649 : 0 : continue;
1650 : 0 : fl->fl_flags |= FL_DOWNGRADE_PENDING;
1651 : 0 : fl->fl_downgrade_time = break_time;
1652 : : }
1653 [ # # ]: 0 : if (fl->fl_lmops->lm_break(fl))
1654 : 0 : locks_delete_lock_ctx(fl, &dispose);
1655 : : }
1656 : :
1657 [ # # ]: 0 : if (list_empty(&ctx->flc_lease))
1658 : 0 : goto out;
1659 : :
1660 [ # # ]: 0 : if (mode & O_NONBLOCK) {
1661 : 0 : trace_break_lease_noblock(inode, new_fl);
1662 : 0 : error = -EWOULDBLOCK;
1663 : 0 : goto out;
1664 : : }
1665 : :
1666 : 0 : restart:
1667 : 0 : fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1668 : 0 : break_time = fl->fl_break_time;
1669 [ # # ]: 0 : if (break_time != 0)
1670 : 0 : break_time -= jiffies;
1671 : 0 : if (break_time == 0)
1672 : : break_time++;
1673 : 0 : locks_insert_block(fl, new_fl, leases_conflict);
1674 : 0 : trace_break_lease_block(inode, new_fl);
1675 : 0 : spin_unlock(&ctx->flc_lock);
1676 : 0 : percpu_up_read(&file_rwsem);
1677 : :
1678 : 0 : locks_dispose_list(&dispose);
1679 [ # # # # : 0 : error = wait_event_interruptible_timeout(new_fl->fl_wait,
# # # # #
# ]
1680 : : list_empty(&new_fl->fl_blocked_member),
1681 : : break_time);
1682 : :
1683 : 0 : percpu_down_read(&file_rwsem);
1684 : 0 : spin_lock(&ctx->flc_lock);
1685 : 0 : trace_break_lease_unblock(inode, new_fl);
1686 : 0 : locks_delete_block(new_fl);
1687 [ # # ]: 0 : if (error >= 0) {
1688 : : /*
1689 : : * Wait for the next conflicting lease that has not been
1690 : : * broken yet
1691 : : */
1692 [ # # ]: 0 : if (error == 0)
1693 : 0 : time_out_leases(inode, &dispose);
1694 [ # # ]: 0 : if (any_leases_conflict(inode, new_fl))
1695 : 0 : goto restart;
1696 : : error = 0;
1697 : : }
1698 : 0 : out:
1699 : 0 : spin_unlock(&ctx->flc_lock);
1700 : 0 : percpu_up_read(&file_rwsem);
1701 : 0 : locks_dispose_list(&dispose);
1702 : 0 : free_lock:
1703 : 0 : locks_free_lock(new_fl);
1704 : 0 : return error;
1705 : : }
1706 : : EXPORT_SYMBOL(__break_lease);
1707 : :
1708 : : /**
1709 : : * lease_get_mtime - update modified time of an inode with exclusive lease
1710 : : * @inode: the inode
1711 : : * @time: pointer to a timespec which contains the last modified time
1712 : : *
1713 : : * This is to force NFS clients to flush their caches for files with
1714 : : * exclusive leases. The justification is that if someone has an
1715 : : * exclusive lease, then they could be modifying it.
1716 : : */
1717 : 0 : void lease_get_mtime(struct inode *inode, struct timespec64 *time)
1718 : : {
1719 : 0 : bool has_lease = false;
1720 : 0 : struct file_lock_context *ctx;
1721 : 0 : struct file_lock *fl;
1722 : :
1723 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
1724 [ # # # # ]: 0 : if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1725 : 0 : spin_lock(&ctx->flc_lock);
1726 [ # # ]: 0 : fl = list_first_entry_or_null(&ctx->flc_lease,
1727 : : struct file_lock, fl_list);
1728 [ # # # # ]: 0 : if (fl && (fl->fl_type == F_WRLCK))
1729 : 0 : has_lease = true;
1730 : 0 : spin_unlock(&ctx->flc_lock);
1731 : : }
1732 : :
1733 [ # # ]: 0 : if (has_lease)
1734 : 0 : *time = current_time(inode);
1735 : 0 : }
1736 : : EXPORT_SYMBOL(lease_get_mtime);
1737 : :
1738 : : /**
1739 : : * fcntl_getlease - Enquire what lease is currently active
1740 : : * @filp: the file
1741 : : *
1742 : : * The value returned by this function will be one of
1743 : : * (if no lease break is pending):
1744 : : *
1745 : : * %F_RDLCK to indicate a shared lease is held.
1746 : : *
1747 : : * %F_WRLCK to indicate an exclusive lease is held.
1748 : : *
1749 : : * %F_UNLCK to indicate no lease is held.
1750 : : *
1751 : : * (if a lease break is pending):
1752 : : *
1753 : : * %F_RDLCK to indicate an exclusive lease needs to be
1754 : : * changed to a shared lease (or removed).
1755 : : *
1756 : : * %F_UNLCK to indicate the lease needs to be removed.
1757 : : *
1758 : : * XXX: sfr & willy disagree over whether F_INPROGRESS
1759 : : * should be returned to userspace.
1760 : : */
1761 : 0 : int fcntl_getlease(struct file *filp)
1762 : : {
1763 : 0 : struct file_lock *fl;
1764 : 0 : struct inode *inode = locks_inode(filp);
1765 : 0 : struct file_lock_context *ctx;
1766 : 0 : int type = F_UNLCK;
1767 : 0 : LIST_HEAD(dispose);
1768 : :
1769 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
1770 [ # # # # ]: 0 : if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1771 : 0 : percpu_down_read(&file_rwsem);
1772 : 0 : spin_lock(&ctx->flc_lock);
1773 : 0 : time_out_leases(inode, &dispose);
1774 [ # # ]: 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1775 [ # # ]: 0 : if (fl->fl_file != filp)
1776 : 0 : continue;
1777 [ # # ]: 0 : type = target_leasetype(fl);
1778 : : break;
1779 : : }
1780 : 0 : spin_unlock(&ctx->flc_lock);
1781 : 0 : percpu_up_read(&file_rwsem);
1782 : :
1783 : 0 : locks_dispose_list(&dispose);
1784 : : }
1785 : 0 : return type;
1786 : : }
1787 : :
1788 : : /**
1789 : : * check_conflicting_open - see if the given file points to an inode that has
1790 : : * an existing open that would conflict with the
1791 : : * desired lease.
1792 : : * @filp: file to check
1793 : : * @arg: type of lease that we're trying to acquire
1794 : : * @flags: current lock flags
1795 : : *
1796 : : * Check to see if there's an existing open fd on this file that would
1797 : : * conflict with the lease we're trying to set.
1798 : : */
1799 : : static int
1800 : 0 : check_conflicting_open(struct file *filp, const long arg, int flags)
1801 : : {
1802 [ # # ]: 0 : struct inode *inode = locks_inode(filp);
1803 : 0 : int self_wcount = 0, self_rcount = 0;
1804 : :
1805 [ # # ]: 0 : if (flags & FL_LAYOUT)
1806 : : return 0;
1807 : :
1808 [ # # ]: 0 : if (arg == F_RDLCK)
1809 [ # # ]: 0 : return inode_is_open_for_write(inode) ? -EAGAIN : 0;
1810 [ # # ]: 0 : else if (arg != F_WRLCK)
1811 : : return 0;
1812 : :
1813 : : /*
1814 : : * Make sure that only read/write count is from lease requestor.
1815 : : * Note that this will result in denying write leases when i_writecount
1816 : : * is negative, which is what we want. (We shouldn't grant write leases
1817 : : * on files open for execution.)
1818 : : */
1819 [ # # ]: 0 : if (filp->f_mode & FMODE_WRITE)
1820 : : self_wcount = 1;
1821 : 0 : else if (filp->f_mode & FMODE_READ)
1822 : : self_rcount = 1;
1823 : :
1824 [ # # # # ]: 0 : if (atomic_read(&inode->i_writecount) != self_wcount ||
1825 : 0 : atomic_read(&inode->i_readcount) != self_rcount)
1826 : 0 : return -EAGAIN;
1827 : :
1828 : : return 0;
1829 : : }
1830 : :
1831 : : static int
1832 : 0 : generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1833 : : {
1834 : 0 : struct file_lock *fl, *my_fl = NULL, *lease;
1835 : 0 : struct inode *inode = locks_inode(filp);
1836 : 0 : struct file_lock_context *ctx;
1837 : 0 : bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1838 : 0 : int error;
1839 : 0 : LIST_HEAD(dispose);
1840 : :
1841 : 0 : lease = *flp;
1842 : 0 : trace_generic_add_lease(inode, lease);
1843 : :
1844 : : /* Note that arg is never F_UNLCK here */
1845 : 0 : ctx = locks_get_lock_context(inode, arg);
1846 [ # # ]: 0 : if (!ctx)
1847 : : return -ENOMEM;
1848 : :
1849 : : /*
1850 : : * In the delegation case we need mutual exclusion with
1851 : : * a number of operations that take the i_mutex. We trylock
1852 : : * because delegations are an optional optimization, and if
1853 : : * there's some chance of a conflict--we'd rather not
1854 : : * bother, maybe that's a sign this just isn't a good file to
1855 : : * hand out a delegation on.
1856 : : */
1857 [ # # # # ]: 0 : if (is_deleg && !inode_trylock(inode))
1858 : : return -EAGAIN;
1859 : :
1860 [ # # ]: 0 : if (is_deleg && arg == F_WRLCK) {
1861 : : /* Write delegations are not currently supported: */
1862 : 0 : inode_unlock(inode);
1863 : 0 : WARN_ON_ONCE(1);
1864 : 0 : return -EINVAL;
1865 : : }
1866 : :
1867 : 0 : percpu_down_read(&file_rwsem);
1868 : 0 : spin_lock(&ctx->flc_lock);
1869 : 0 : time_out_leases(inode, &dispose);
1870 : 0 : error = check_conflicting_open(filp, arg, lease->fl_flags);
1871 [ # # ]: 0 : if (error)
1872 : 0 : goto out;
1873 : :
1874 : : /*
1875 : : * At this point, we know that if there is an exclusive
1876 : : * lease on this file, then we hold it on this filp
1877 : : * (otherwise our open of this file would have blocked).
1878 : : * And if we are trying to acquire an exclusive lease,
1879 : : * then the file is not open by anyone (including us)
1880 : : * except for this filp.
1881 : : */
1882 : 0 : error = -EAGAIN;
1883 [ # # ]: 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1884 [ # # ]: 0 : if (fl->fl_file == filp &&
1885 [ # # ]: 0 : fl->fl_owner == lease->fl_owner) {
1886 : 0 : my_fl = fl;
1887 : 0 : continue;
1888 : : }
1889 : :
1890 : : /*
1891 : : * No exclusive leases if someone else has a lease on
1892 : : * this file:
1893 : : */
1894 [ # # ]: 0 : if (arg == F_WRLCK)
1895 : 0 : goto out;
1896 : : /*
1897 : : * Modifying our existing lease is OK, but no getting a
1898 : : * new lease if someone else is opening for write:
1899 : : */
1900 [ # # ]: 0 : if (fl->fl_flags & FL_UNLOCK_PENDING)
1901 : 0 : goto out;
1902 : : }
1903 : :
1904 [ # # ]: 0 : if (my_fl != NULL) {
1905 : 0 : lease = my_fl;
1906 : 0 : error = lease->fl_lmops->lm_change(lease, arg, &dispose);
1907 [ # # ]: 0 : if (error)
1908 : 0 : goto out;
1909 : 0 : goto out_setup;
1910 : : }
1911 : :
1912 : 0 : error = -EINVAL;
1913 [ # # ]: 0 : if (!leases_enable)
1914 : 0 : goto out;
1915 : :
1916 : 0 : locks_insert_lock_ctx(lease, &ctx->flc_lease);
1917 : : /*
1918 : : * The check in break_lease() is lockless. It's possible for another
1919 : : * open to race in after we did the earlier check for a conflicting
1920 : : * open but before the lease was inserted. Check again for a
1921 : : * conflicting open and cancel the lease if there is one.
1922 : : *
1923 : : * We also add a barrier here to ensure that the insertion of the lock
1924 : : * precedes these checks.
1925 : : */
1926 : 0 : smp_mb();
1927 : 0 : error = check_conflicting_open(filp, arg, lease->fl_flags);
1928 [ # # ]: 0 : if (error) {
1929 : 0 : locks_unlink_lock_ctx(lease);
1930 : 0 : goto out;
1931 : : }
1932 : :
1933 : 0 : out_setup:
1934 [ # # ]: 0 : if (lease->fl_lmops->lm_setup)
1935 : 0 : lease->fl_lmops->lm_setup(lease, priv);
1936 : 0 : out:
1937 : 0 : spin_unlock(&ctx->flc_lock);
1938 : 0 : percpu_up_read(&file_rwsem);
1939 : 0 : locks_dispose_list(&dispose);
1940 [ # # ]: 0 : if (is_deleg)
1941 : 0 : inode_unlock(inode);
1942 [ # # ]: 0 : if (!error && !my_fl)
1943 : 0 : *flp = NULL;
1944 : : return error;
1945 : : }
1946 : :
1947 : 0 : static int generic_delete_lease(struct file *filp, void *owner)
1948 : : {
1949 : 0 : int error = -EAGAIN;
1950 : 0 : struct file_lock *fl, *victim = NULL;
1951 : 0 : struct inode *inode = locks_inode(filp);
1952 : 0 : struct file_lock_context *ctx;
1953 : 0 : LIST_HEAD(dispose);
1954 : :
1955 : 0 : ctx = smp_load_acquire(&inode->i_flctx);
1956 [ # # ]: 0 : if (!ctx) {
1957 : 0 : trace_generic_delete_lease(inode, NULL);
1958 : 0 : return error;
1959 : : }
1960 : :
1961 : 0 : percpu_down_read(&file_rwsem);
1962 : 0 : spin_lock(&ctx->flc_lock);
1963 [ # # ]: 0 : list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1964 [ # # ]: 0 : if (fl->fl_file == filp &&
1965 [ # # ]: 0 : fl->fl_owner == owner) {
1966 : : victim = fl;
1967 : : break;
1968 : : }
1969 : : }
1970 : 0 : trace_generic_delete_lease(inode, victim);
1971 [ # # ]: 0 : if (victim)
1972 : 0 : error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
1973 : 0 : spin_unlock(&ctx->flc_lock);
1974 : 0 : percpu_up_read(&file_rwsem);
1975 : 0 : locks_dispose_list(&dispose);
1976 : 0 : return error;
1977 : : }
1978 : :
1979 : : /**
1980 : : * generic_setlease - sets a lease on an open file
1981 : : * @filp: file pointer
1982 : : * @arg: type of lease to obtain
1983 : : * @flp: input - file_lock to use, output - file_lock inserted
1984 : : * @priv: private data for lm_setup (may be NULL if lm_setup
1985 : : * doesn't require it)
1986 : : *
1987 : : * The (input) flp->fl_lmops->lm_break function is required
1988 : : * by break_lease().
1989 : : */
1990 : 0 : int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1991 : : void **priv)
1992 : : {
1993 [ # # ]: 0 : struct inode *inode = locks_inode(filp);
1994 : 0 : int error;
1995 : :
1996 [ # # # # ]: 0 : if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1997 : : return -EACCES;
1998 [ # # ]: 0 : if (!S_ISREG(inode->i_mode))
1999 : : return -EINVAL;
2000 : 0 : error = security_file_lock(filp, arg);
2001 [ # # ]: 0 : if (error)
2002 : : return error;
2003 : :
2004 [ # # # ]: 0 : switch (arg) {
2005 : 0 : case F_UNLCK:
2006 : 0 : return generic_delete_lease(filp, *priv);
2007 : 0 : case F_RDLCK:
2008 : : case F_WRLCK:
2009 [ # # ]: 0 : if (!(*flp)->fl_lmops->lm_break) {
2010 : 0 : WARN_ON_ONCE(1);
2011 : 0 : return -ENOLCK;
2012 : : }
2013 : :
2014 : 0 : return generic_add_lease(filp, arg, flp, priv);
2015 : : default:
2016 : : return -EINVAL;
2017 : : }
2018 : : }
2019 : : EXPORT_SYMBOL(generic_setlease);
2020 : :
2021 : : #if IS_ENABLED(CONFIG_SRCU)
2022 : : /*
2023 : : * Kernel subsystems can register to be notified on any attempt to set
2024 : : * a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd
2025 : : * to close files that it may have cached when there is an attempt to set a
2026 : : * conflicting lease.
2027 : : */
2028 : : static struct srcu_notifier_head lease_notifier_chain;
2029 : :
2030 : : static inline void
2031 : 78 : lease_notifier_chain_init(void)
2032 : : {
2033 : 78 : srcu_init_notifier_head(&lease_notifier_chain);
2034 : : }
2035 : :
2036 : : static inline void
2037 : 0 : setlease_notifier(long arg, struct file_lock *lease)
2038 : : {
2039 : 0 : if (arg != F_UNLCK)
2040 : 0 : srcu_notifier_call_chain(&lease_notifier_chain, arg, lease);
2041 : : }
2042 : :
2043 : 0 : int lease_register_notifier(struct notifier_block *nb)
2044 : : {
2045 : 0 : return srcu_notifier_chain_register(&lease_notifier_chain, nb);
2046 : : }
2047 : : EXPORT_SYMBOL_GPL(lease_register_notifier);
2048 : :
2049 : 0 : void lease_unregister_notifier(struct notifier_block *nb)
2050 : : {
2051 : 0 : srcu_notifier_chain_unregister(&lease_notifier_chain, nb);
2052 : 0 : }
2053 : : EXPORT_SYMBOL_GPL(lease_unregister_notifier);
2054 : :
2055 : : #else /* !IS_ENABLED(CONFIG_SRCU) */
2056 : : static inline void
2057 : : lease_notifier_chain_init(void)
2058 : : {
2059 : : }
2060 : :
2061 : : static inline void
2062 : : setlease_notifier(long arg, struct file_lock *lease)
2063 : : {
2064 : : }
2065 : :
2066 : : int lease_register_notifier(struct notifier_block *nb)
2067 : : {
2068 : : return 0;
2069 : : }
2070 : : EXPORT_SYMBOL_GPL(lease_register_notifier);
2071 : :
2072 : : void lease_unregister_notifier(struct notifier_block *nb)
2073 : : {
2074 : : }
2075 : : EXPORT_SYMBOL_GPL(lease_unregister_notifier);
2076 : :
2077 : : #endif /* IS_ENABLED(CONFIG_SRCU) */
2078 : :
2079 : : /**
2080 : : * vfs_setlease - sets a lease on an open file
2081 : : * @filp: file pointer
2082 : : * @arg: type of lease to obtain
2083 : : * @lease: file_lock to use when adding a lease
2084 : : * @priv: private info for lm_setup when adding a lease (may be
2085 : : * NULL if lm_setup doesn't require it)
2086 : : *
2087 : : * Call this to establish a lease on the file. The "lease" argument is not
2088 : : * used for F_UNLCK requests and may be NULL. For commands that set or alter
2089 : : * an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be
2090 : : * set; if not, this function will return -ENOLCK (and generate a scary-looking
2091 : : * stack trace).
2092 : : *
2093 : : * The "priv" pointer is passed directly to the lm_setup function as-is. It
2094 : : * may be NULL if the lm_setup operation doesn't require it.
2095 : : */
2096 : : int
2097 : 0 : vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
2098 : : {
2099 [ # # ]: 0 : if (lease)
2100 [ # # ]: 0 : setlease_notifier(arg, *lease);
2101 [ # # ]: 0 : if (filp->f_op->setlease)
2102 : 0 : return filp->f_op->setlease(filp, arg, lease, priv);
2103 : : else
2104 : 0 : return generic_setlease(filp, arg, lease, priv);
2105 : : }
2106 : : EXPORT_SYMBOL_GPL(vfs_setlease);
2107 : :
2108 : 0 : static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
2109 : : {
2110 : 0 : struct file_lock *fl;
2111 : 0 : struct fasync_struct *new;
2112 : 0 : int error;
2113 : :
2114 : 0 : fl = lease_alloc(filp, arg);
2115 [ # # ]: 0 : if (IS_ERR(fl))
2116 : 0 : return PTR_ERR(fl);
2117 : :
2118 : 0 : new = fasync_alloc();
2119 [ # # ]: 0 : if (!new) {
2120 : 0 : locks_free_lock(fl);
2121 : 0 : return -ENOMEM;
2122 : : }
2123 : 0 : new->fa_fd = fd;
2124 : :
2125 : 0 : error = vfs_setlease(filp, arg, &fl, (void **)&new);
2126 [ # # ]: 0 : if (fl)
2127 : 0 : locks_free_lock(fl);
2128 [ # # ]: 0 : if (new)
2129 : 0 : fasync_free(new);
2130 : : return error;
2131 : : }
2132 : :
2133 : : /**
2134 : : * fcntl_setlease - sets a lease on an open file
2135 : : * @fd: open file descriptor
2136 : : * @filp: file pointer
2137 : : * @arg: type of lease to obtain
2138 : : *
2139 : : * Call this fcntl to establish a lease on the file.
2140 : : * Note that you also need to call %F_SETSIG to
2141 : : * receive a signal when the lease is broken.
2142 : : */
2143 : 0 : int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
2144 : : {
2145 [ # # ]: 0 : if (arg == F_UNLCK)
2146 : 0 : return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
2147 : 0 : return do_fcntl_add_lease(fd, filp, arg);
2148 : : }
2149 : :
2150 : : /**
2151 : : * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
2152 : : * @inode: inode of the file to apply to
2153 : : * @fl: The lock to be applied
2154 : : *
2155 : : * Apply a FLOCK style lock request to an inode.
2156 : : */
2157 : 936 : static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
2158 : : {
2159 : 936 : int error;
2160 : 936 : might_sleep();
2161 : 936 : for (;;) {
2162 : 936 : error = flock_lock_inode(inode, fl);
2163 [ - + ]: 936 : if (error != FILE_LOCK_DEFERRED)
2164 : : break;
2165 [ # # # # : 0 : error = wait_event_interruptible(fl->fl_wait,
# # ]
2166 : : list_empty(&fl->fl_blocked_member));
2167 [ # # ]: 0 : if (error)
2168 : : break;
2169 : : }
2170 : 936 : locks_delete_block(fl);
2171 : 936 : return error;
2172 : : }
2173 : :
2174 : : /**
2175 : : * locks_lock_inode_wait - Apply a lock to an inode
2176 : : * @inode: inode of the file to apply to
2177 : : * @fl: The lock to be applied
2178 : : *
2179 : : * Apply a POSIX or FLOCK style lock request to an inode.
2180 : : */
2181 : 936 : int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
2182 : : {
2183 : 936 : int res = 0;
2184 [ - + - ]: 936 : switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
2185 : 0 : case FL_POSIX:
2186 : 0 : res = posix_lock_inode_wait(inode, fl);
2187 : 0 : break;
2188 : 936 : case FL_FLOCK:
2189 : 936 : res = flock_lock_inode_wait(inode, fl);
2190 : 936 : break;
2191 : 0 : default:
2192 : 0 : BUG();
2193 : : }
2194 : 936 : return res;
2195 : : }
2196 : : EXPORT_SYMBOL(locks_lock_inode_wait);
2197 : :
2198 : : /**
2199 : : * sys_flock: - flock() system call.
2200 : : * @fd: the file descriptor to lock.
2201 : : * @cmd: the type of lock to apply.
2202 : : *
2203 : : * Apply a %FL_FLOCK style lock to an open file descriptor.
2204 : : * The @cmd can be one of:
2205 : : *
2206 : : * - %LOCK_SH -- a shared lock.
2207 : : * - %LOCK_EX -- an exclusive lock.
2208 : : * - %LOCK_UN -- remove an existing lock.
2209 : : * - %LOCK_MAND -- a 'mandatory' flock.
2210 : : * This exists to emulate Windows Share Modes.
2211 : : *
2212 : : * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
2213 : : * processes read and write access respectively.
2214 : : */
2215 : 1872 : SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
2216 : : {
2217 : 936 : struct fd f = fdget(fd);
2218 : 936 : struct file_lock *lock;
2219 : 936 : int can_sleep, unlock;
2220 : 936 : int error;
2221 : :
2222 : 936 : error = -EBADF;
2223 [ - + ]: 936 : if (!f.file)
2224 : 0 : goto out;
2225 : :
2226 : 936 : can_sleep = !(cmd & LOCK_NB);
2227 : 936 : cmd &= ~LOCK_NB;
2228 : 936 : unlock = (cmd == LOCK_UN);
2229 : :
2230 [ + - + - ]: 936 : if (!unlock && !(cmd & LOCK_MAND) &&
2231 [ - + ]: 936 : !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
2232 : 0 : goto out_putf;
2233 : :
2234 : 936 : lock = flock_make_lock(f.file, cmd, NULL);
2235 [ - + ]: 936 : if (IS_ERR(lock)) {
2236 : 0 : error = PTR_ERR(lock);
2237 : 0 : goto out_putf;
2238 : : }
2239 : :
2240 [ - + ]: 936 : if (can_sleep)
2241 : 0 : lock->fl_flags |= FL_SLEEP;
2242 : :
2243 : 936 : error = security_file_lock(f.file, lock->fl_type);
2244 [ - + ]: 936 : if (error)
2245 : 0 : goto out_free;
2246 : :
2247 [ - + ]: 936 : if (f.file->f_op->flock)
2248 [ # # ]: 0 : error = f.file->f_op->flock(f.file,
2249 : : (can_sleep) ? F_SETLKW : F_SETLK,
2250 : : lock);
2251 : : else
2252 : 936 : error = locks_lock_file_wait(f.file, lock);
2253 : :
2254 : 936 : out_free:
2255 : 936 : locks_free_lock(lock);
2256 : :
2257 : 936 : out_putf:
2258 [ - + ]: 936 : fdput(f);
2259 : 936 : out:
2260 : 936 : return error;
2261 : : }
2262 : :
2263 : : /**
2264 : : * vfs_test_lock - test file byte range lock
2265 : : * @filp: The file to test lock for
2266 : : * @fl: The lock to test; also used to hold result
2267 : : *
2268 : : * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2269 : : * setting conf->fl_type to something other than F_UNLCK.
2270 : : */
2271 : 0 : int vfs_test_lock(struct file *filp, struct file_lock *fl)
2272 : : {
2273 [ # # ]: 0 : if (filp->f_op->lock)
2274 : 0 : return filp->f_op->lock(filp, F_GETLK, fl);
2275 : 0 : posix_test_lock(filp, fl);
2276 : 0 : return 0;
2277 : : }
2278 : : EXPORT_SYMBOL_GPL(vfs_test_lock);
2279 : :
2280 : : /**
2281 : : * locks_translate_pid - translate a file_lock's fl_pid number into a namespace
2282 : : * @fl: The file_lock who's fl_pid should be translated
2283 : : * @ns: The namespace into which the pid should be translated
2284 : : *
2285 : : * Used to tranlate a fl_pid into a namespace virtual pid number
2286 : : */
2287 : : static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns)
2288 : : {
2289 : : pid_t vnr;
2290 : : struct pid *pid;
2291 : :
2292 : : if (IS_OFDLCK(fl))
2293 : : return -1;
2294 : : if (IS_REMOTELCK(fl))
2295 : : return fl->fl_pid;
2296 : : /*
2297 : : * If the flock owner process is dead and its pid has been already
2298 : : * freed, the translation below won't work, but we still want to show
2299 : : * flock owner pid number in init pidns.
2300 : : */
2301 : : if (ns == &init_pid_ns)
2302 : : return (pid_t)fl->fl_pid;
2303 : :
2304 : : rcu_read_lock();
2305 : : pid = find_pid_ns(fl->fl_pid, &init_pid_ns);
2306 : : vnr = pid_nr_ns(pid, ns);
2307 : : rcu_read_unlock();
2308 : : return vnr;
2309 : : }
2310 : :
2311 : 0 : static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2312 : : {
2313 : 0 : flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
2314 : : #if BITS_PER_LONG == 32
2315 : : /*
2316 : : * Make sure we can represent the posix lock via
2317 : : * legacy 32bit flock.
2318 : : */
2319 : : if (fl->fl_start > OFFT_OFFSET_MAX)
2320 : : return -EOVERFLOW;
2321 : : if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2322 : : return -EOVERFLOW;
2323 : : #endif
2324 : 0 : flock->l_start = fl->fl_start;
2325 [ # # ]: 0 : flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2326 : 0 : fl->fl_end - fl->fl_start + 1;
2327 : 0 : flock->l_whence = 0;
2328 : 0 : flock->l_type = fl->fl_type;
2329 : 0 : return 0;
2330 : : }
2331 : :
2332 : : #if BITS_PER_LONG == 32
2333 : : static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2334 : : {
2335 : : flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
2336 : : flock->l_start = fl->fl_start;
2337 : : flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2338 : : fl->fl_end - fl->fl_start + 1;
2339 : : flock->l_whence = 0;
2340 : : flock->l_type = fl->fl_type;
2341 : : }
2342 : : #endif
2343 : :
2344 : : /* Report the first existing lock that would conflict with l.
2345 : : * This implements the F_GETLK command of fcntl().
2346 : : */
2347 : 0 : int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
2348 : : {
2349 : 0 : struct file_lock *fl;
2350 : 0 : int error;
2351 : :
2352 : 0 : fl = locks_alloc_lock();
2353 [ # # ]: 0 : if (fl == NULL)
2354 : : return -ENOMEM;
2355 : 0 : error = -EINVAL;
2356 [ # # ]: 0 : if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
2357 : 0 : goto out;
2358 : :
2359 : 0 : error = flock_to_posix_lock(filp, fl, flock);
2360 [ # # ]: 0 : if (error)
2361 : 0 : goto out;
2362 : :
2363 [ # # ]: 0 : if (cmd == F_OFD_GETLK) {
2364 : 0 : error = -EINVAL;
2365 [ # # ]: 0 : if (flock->l_pid != 0)
2366 : 0 : goto out;
2367 : :
2368 : 0 : cmd = F_GETLK;
2369 : 0 : fl->fl_flags |= FL_OFDLCK;
2370 : 0 : fl->fl_owner = filp;
2371 : : }
2372 : :
2373 : 0 : error = vfs_test_lock(filp, fl);
2374 [ # # ]: 0 : if (error)
2375 : 0 : goto out;
2376 : :
2377 : 0 : flock->l_type = fl->fl_type;
2378 [ # # ]: 0 : if (fl->fl_type != F_UNLCK) {
2379 : 0 : error = posix_lock_to_flock(flock, fl);
2380 [ # # ]: 0 : if (error)
2381 : 0 : goto out;
2382 : : }
2383 : 0 : out:
2384 : 0 : locks_free_lock(fl);
2385 : 0 : return error;
2386 : : }
2387 : :
2388 : : /**
2389 : : * vfs_lock_file - file byte range lock
2390 : : * @filp: The file to apply the lock to
2391 : : * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2392 : : * @fl: The lock to be applied
2393 : : * @conf: Place to return a copy of the conflicting lock, if found.
2394 : : *
2395 : : * A caller that doesn't care about the conflicting lock may pass NULL
2396 : : * as the final argument.
2397 : : *
2398 : : * If the filesystem defines a private ->lock() method, then @conf will
2399 : : * be left unchanged; so a caller that cares should initialize it to
2400 : : * some acceptable default.
2401 : : *
2402 : : * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2403 : : * locks, the ->lock() interface may return asynchronously, before the lock has
2404 : : * been granted or denied by the underlying filesystem, if (and only if)
2405 : : * lm_grant is set. Callers expecting ->lock() to return asynchronously
2406 : : * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2407 : : * the request is for a blocking lock. When ->lock() does return asynchronously,
2408 : : * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2409 : : * request completes.
2410 : : * If the request is for non-blocking lock the file system should return
2411 : : * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2412 : : * with the result. If the request timed out the callback routine will return a
2413 : : * nonzero return code and the file system should release the lock. The file
2414 : : * system is also responsible to keep a corresponding posix lock when it
2415 : : * grants a lock so the VFS can find out which locks are locally held and do
2416 : : * the correct lock cleanup when required.
2417 : : * The underlying filesystem must not drop the kernel lock or call
2418 : : * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2419 : : * return code.
2420 : : */
2421 : 1404 : int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2422 : : {
2423 [ - + ]: 1404 : if (filp->f_op->lock)
2424 : 0 : return filp->f_op->lock(filp, cmd, fl);
2425 : : else
2426 : 1404 : return posix_lock_file(filp, fl, conf);
2427 : : }
2428 : : EXPORT_SYMBOL_GPL(vfs_lock_file);
2429 : :
2430 : 624 : static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2431 : : struct file_lock *fl)
2432 : : {
2433 : 624 : int error;
2434 : :
2435 : 624 : error = security_file_lock(filp, fl->fl_type);
2436 [ + - ]: 624 : if (error)
2437 : : return error;
2438 : :
2439 : 624 : for (;;) {
2440 : 624 : error = vfs_lock_file(filp, cmd, fl, NULL);
2441 [ - + ]: 624 : if (error != FILE_LOCK_DEFERRED)
2442 : : break;
2443 [ # # # # : 0 : error = wait_event_interruptible(fl->fl_wait,
# # ]
2444 : : list_empty(&fl->fl_blocked_member));
2445 [ # # ]: 0 : if (error)
2446 : : break;
2447 : : }
2448 : 624 : locks_delete_block(fl);
2449 : :
2450 : 624 : return error;
2451 : : }
2452 : :
2453 : : /* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
2454 : : static int
2455 : 624 : check_fmode_for_setlk(struct file_lock *fl)
2456 : : {
2457 : 624 : switch (fl->fl_type) {
2458 : 0 : case F_RDLCK:
2459 [ # # ]: 0 : if (!(fl->fl_file->f_mode & FMODE_READ))
2460 : : return -EBADF;
2461 : : break;
2462 : 546 : case F_WRLCK:
2463 [ - + ]: 546 : if (!(fl->fl_file->f_mode & FMODE_WRITE))
2464 : : return -EBADF;
2465 : : }
2466 : : return 0;
2467 : : }
2468 : :
2469 : : /* Apply the lock described by l to an open file descriptor.
2470 : : * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2471 : : */
2472 : 624 : int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2473 : : struct flock *flock)
2474 : : {
2475 : 624 : struct file_lock *file_lock = locks_alloc_lock();
2476 [ + - ]: 624 : struct inode *inode = locks_inode(filp);
2477 : 624 : struct file *f;
2478 : 624 : int error;
2479 : :
2480 [ + - ]: 624 : if (file_lock == NULL)
2481 : : return -ENOLCK;
2482 : :
2483 : : /* Don't allow mandatory locks on files that may be memory mapped
2484 : : * and shared.
2485 : : */
2486 [ - + - - ]: 624 : if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2487 : 0 : error = -EAGAIN;
2488 : 0 : goto out;
2489 : : }
2490 : :
2491 : 624 : error = flock_to_posix_lock(filp, file_lock, flock);
2492 [ - + ]: 624 : if (error)
2493 : 0 : goto out;
2494 : :
2495 [ - + + ]: 624 : error = check_fmode_for_setlk(file_lock);
2496 : : if (error)
2497 : 0 : goto out;
2498 : :
2499 : : /*
2500 : : * If the cmd is requesting file-private locks, then set the
2501 : : * FL_OFDLCK flag and override the owner.
2502 : : */
2503 [ - - + + ]: 624 : switch (cmd) {
2504 : 0 : case F_OFD_SETLK:
2505 : 0 : error = -EINVAL;
2506 [ # # ]: 0 : if (flock->l_pid != 0)
2507 : 0 : goto out;
2508 : :
2509 : 0 : cmd = F_SETLK;
2510 : 0 : file_lock->fl_flags |= FL_OFDLCK;
2511 : 0 : file_lock->fl_owner = filp;
2512 : 0 : break;
2513 : 0 : case F_OFD_SETLKW:
2514 : 0 : error = -EINVAL;
2515 [ # # ]: 0 : if (flock->l_pid != 0)
2516 : 0 : goto out;
2517 : :
2518 : 0 : cmd = F_SETLKW;
2519 : 0 : file_lock->fl_flags |= FL_OFDLCK;
2520 : 0 : file_lock->fl_owner = filp;
2521 : : /* Fallthrough */
2522 : 546 : case F_SETLKW:
2523 : 546 : file_lock->fl_flags |= FL_SLEEP;
2524 : : }
2525 : :
2526 : 624 : error = do_lock_file_wait(filp, cmd, file_lock);
2527 : :
2528 : : /*
2529 : : * Attempt to detect a close/fcntl race and recover by releasing the
2530 : : * lock that was just acquired. There is no need to do that when we're
2531 : : * unlocking though, or for OFD locks.
2532 : : */
2533 [ - + + + ]: 624 : if (!error && file_lock->fl_type != F_UNLCK &&
2534 [ - + ]: 546 : !(file_lock->fl_flags & FL_OFDLCK)) {
2535 : : /*
2536 : : * We need that spin_lock here - it prevents reordering between
2537 : : * update of i_flctx->flc_posix and check for it done in
2538 : : * close(). rcu_read_lock() wouldn't do.
2539 : : */
2540 : 546 : spin_lock(¤t->files->file_lock);
2541 [ + - ]: 546 : f = fcheck(fd);
2542 : 546 : spin_unlock(¤t->files->file_lock);
2543 [ + - ]: 546 : if (f != filp) {
2544 : 0 : file_lock->fl_type = F_UNLCK;
2545 : 0 : error = do_lock_file_wait(filp, cmd, file_lock);
2546 [ # # ]: 0 : WARN_ON_ONCE(error);
2547 : : error = -EBADF;
2548 : : }
2549 : : }
2550 : 624 : out:
2551 : 624 : trace_fcntl_setlk(inode, file_lock, error);
2552 : 624 : locks_free_lock(file_lock);
2553 : 624 : return error;
2554 : : }
2555 : :
2556 : : #if BITS_PER_LONG == 32
2557 : : /* Report the first existing lock that would conflict with l.
2558 : : * This implements the F_GETLK command of fcntl().
2559 : : */
2560 : : int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
2561 : : {
2562 : : struct file_lock *fl;
2563 : : int error;
2564 : :
2565 : : fl = locks_alloc_lock();
2566 : : if (fl == NULL)
2567 : : return -ENOMEM;
2568 : :
2569 : : error = -EINVAL;
2570 : : if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
2571 : : goto out;
2572 : :
2573 : : error = flock64_to_posix_lock(filp, fl, flock);
2574 : : if (error)
2575 : : goto out;
2576 : :
2577 : : if (cmd == F_OFD_GETLK) {
2578 : : error = -EINVAL;
2579 : : if (flock->l_pid != 0)
2580 : : goto out;
2581 : :
2582 : : cmd = F_GETLK64;
2583 : : fl->fl_flags |= FL_OFDLCK;
2584 : : fl->fl_owner = filp;
2585 : : }
2586 : :
2587 : : error = vfs_test_lock(filp, fl);
2588 : : if (error)
2589 : : goto out;
2590 : :
2591 : : flock->l_type = fl->fl_type;
2592 : : if (fl->fl_type != F_UNLCK)
2593 : : posix_lock_to_flock64(flock, fl);
2594 : :
2595 : : out:
2596 : : locks_free_lock(fl);
2597 : : return error;
2598 : : }
2599 : :
2600 : : /* Apply the lock described by l to an open file descriptor.
2601 : : * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2602 : : */
2603 : : int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2604 : : struct flock64 *flock)
2605 : : {
2606 : : struct file_lock *file_lock = locks_alloc_lock();
2607 : : struct inode *inode = locks_inode(filp);
2608 : : struct file *f;
2609 : : int error;
2610 : :
2611 : : if (file_lock == NULL)
2612 : : return -ENOLCK;
2613 : :
2614 : : /* Don't allow mandatory locks on files that may be memory mapped
2615 : : * and shared.
2616 : : */
2617 : : if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2618 : : error = -EAGAIN;
2619 : : goto out;
2620 : : }
2621 : :
2622 : : error = flock64_to_posix_lock(filp, file_lock, flock);
2623 : : if (error)
2624 : : goto out;
2625 : :
2626 : : error = check_fmode_for_setlk(file_lock);
2627 : : if (error)
2628 : : goto out;
2629 : :
2630 : : /*
2631 : : * If the cmd is requesting file-private locks, then set the
2632 : : * FL_OFDLCK flag and override the owner.
2633 : : */
2634 : : switch (cmd) {
2635 : : case F_OFD_SETLK:
2636 : : error = -EINVAL;
2637 : : if (flock->l_pid != 0)
2638 : : goto out;
2639 : :
2640 : : cmd = F_SETLK64;
2641 : : file_lock->fl_flags |= FL_OFDLCK;
2642 : : file_lock->fl_owner = filp;
2643 : : break;
2644 : : case F_OFD_SETLKW:
2645 : : error = -EINVAL;
2646 : : if (flock->l_pid != 0)
2647 : : goto out;
2648 : :
2649 : : cmd = F_SETLKW64;
2650 : : file_lock->fl_flags |= FL_OFDLCK;
2651 : : file_lock->fl_owner = filp;
2652 : : /* Fallthrough */
2653 : : case F_SETLKW64:
2654 : : file_lock->fl_flags |= FL_SLEEP;
2655 : : }
2656 : :
2657 : : error = do_lock_file_wait(filp, cmd, file_lock);
2658 : :
2659 : : /*
2660 : : * Attempt to detect a close/fcntl race and recover by releasing the
2661 : : * lock that was just acquired. There is no need to do that when we're
2662 : : * unlocking though, or for OFD locks.
2663 : : */
2664 : : if (!error && file_lock->fl_type != F_UNLCK &&
2665 : : !(file_lock->fl_flags & FL_OFDLCK)) {
2666 : : /*
2667 : : * We need that spin_lock here - it prevents reordering between
2668 : : * update of i_flctx->flc_posix and check for it done in
2669 : : * close(). rcu_read_lock() wouldn't do.
2670 : : */
2671 : : spin_lock(¤t->files->file_lock);
2672 : : f = fcheck(fd);
2673 : : spin_unlock(¤t->files->file_lock);
2674 : : if (f != filp) {
2675 : : file_lock->fl_type = F_UNLCK;
2676 : : error = do_lock_file_wait(filp, cmd, file_lock);
2677 : : WARN_ON_ONCE(error);
2678 : : error = -EBADF;
2679 : : }
2680 : : }
2681 : : out:
2682 : : locks_free_lock(file_lock);
2683 : : return error;
2684 : : }
2685 : : #endif /* BITS_PER_LONG == 32 */
2686 : :
2687 : : /*
2688 : : * This function is called when the file is being removed
2689 : : * from the task's fd array. POSIX locks belonging to this task
2690 : : * are deleted at this time.
2691 : : */
2692 : 2316260 : void locks_remove_posix(struct file *filp, fl_owner_t owner)
2693 : : {
2694 : 2316260 : int error;
2695 : 2316260 : struct inode *inode = locks_inode(filp);
2696 : 2316260 : struct file_lock lock;
2697 : 2316260 : struct file_lock_context *ctx;
2698 : :
2699 : : /*
2700 : : * If there are no locks held on this file, we don't need to call
2701 : : * posix_lock_file(). Another process could be setting a lock on this
2702 : : * file at the same time, but we wouldn't remove that lock anyway.
2703 : : */
2704 : 2316260 : ctx = smp_load_acquire(&inode->i_flctx);
2705 [ + + + + ]: 2316260 : if (!ctx || list_empty(&ctx->flc_posix))
2706 : 2315480 : return;
2707 : :
2708 : 780 : locks_init_lock(&lock);
2709 : 780 : lock.fl_type = F_UNLCK;
2710 : 780 : lock.fl_flags = FL_POSIX | FL_CLOSE;
2711 : 780 : lock.fl_start = 0;
2712 : 780 : lock.fl_end = OFFSET_MAX;
2713 : 780 : lock.fl_owner = owner;
2714 : 780 : lock.fl_pid = current->tgid;
2715 : 780 : lock.fl_file = filp;
2716 : 780 : lock.fl_ops = NULL;
2717 : 780 : lock.fl_lmops = NULL;
2718 : :
2719 : 780 : error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
2720 : :
2721 [ - + - - ]: 780 : if (lock.fl_ops && lock.fl_ops->fl_release_private)
2722 : 0 : lock.fl_ops->fl_release_private(&lock);
2723 : 780 : trace_locks_remove_posix(inode, &lock, error);
2724 : : }
2725 : : EXPORT_SYMBOL(locks_remove_posix);
2726 : :
2727 : : /* The i_flctx must be valid when calling into here */
2728 : : static void
2729 : 2574 : locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
2730 : : {
2731 : 2574 : struct file_lock fl;
2732 [ + + ]: 2574 : struct inode *inode = locks_inode(filp);
2733 : :
2734 [ + + ]: 2574 : if (list_empty(&flctx->flc_flock))
2735 : 624 : return;
2736 : :
2737 : 1950 : flock_make_lock(filp, LOCK_UN, &fl);
2738 : 1950 : fl.fl_flags |= FL_CLOSE;
2739 : :
2740 [ - + ]: 1950 : if (filp->f_op->flock)
2741 : 0 : filp->f_op->flock(filp, F_SETLKW, &fl);
2742 : : else
2743 : 1950 : flock_lock_inode(inode, &fl);
2744 : :
2745 [ - + - - ]: 1950 : if (fl.fl_ops && fl.fl_ops->fl_release_private)
2746 : 0 : fl.fl_ops->fl_release_private(&fl);
2747 : : }
2748 : :
2749 : : /* The i_flctx must be valid when calling into here */
2750 : : static void
2751 : 2574 : locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
2752 : : {
2753 : 2574 : struct file_lock *fl, *tmp;
2754 : 2574 : LIST_HEAD(dispose);
2755 : :
2756 [ + - ]: 2574 : if (list_empty(&ctx->flc_lease))
2757 : 2574 : return;
2758 : :
2759 : 0 : percpu_down_read(&file_rwsem);
2760 : 0 : spin_lock(&ctx->flc_lock);
2761 [ # # ]: 0 : list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
2762 [ # # ]: 0 : if (filp == fl->fl_file)
2763 : 0 : lease_modify(fl, F_UNLCK, &dispose);
2764 : 0 : spin_unlock(&ctx->flc_lock);
2765 : 0 : percpu_up_read(&file_rwsem);
2766 : :
2767 : 0 : locks_dispose_list(&dispose);
2768 : : }
2769 : :
2770 : : /*
2771 : : * This function is called on the last close of an open file.
2772 : : */
2773 : 3351823 : void locks_remove_file(struct file *filp)
2774 : : {
2775 : 3351823 : struct file_lock_context *ctx;
2776 : :
2777 : 3351823 : ctx = smp_load_acquire(&locks_inode(filp)->i_flctx);
2778 [ + + ]: 3351823 : if (!ctx)
2779 : : return;
2780 : :
2781 : : /* remove any OFD locks */
2782 : 2574 : locks_remove_posix(filp, filp);
2783 : :
2784 : : /* remove flock locks */
2785 : 2574 : locks_remove_flock(filp, ctx);
2786 : :
2787 : : /* remove any leases */
2788 : 2574 : locks_remove_lease(filp, ctx);
2789 : :
2790 : 2574 : spin_lock(&ctx->flc_lock);
2791 : 2574 : locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX");
2792 : 2574 : locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK");
2793 : 2574 : locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE");
2794 : 2574 : spin_unlock(&ctx->flc_lock);
2795 : : }
2796 : :
2797 : : /**
2798 : : * vfs_cancel_lock - file byte range unblock lock
2799 : : * @filp: The file to apply the unblock to
2800 : : * @fl: The lock to be unblocked
2801 : : *
2802 : : * Used by lock managers to cancel blocked requests
2803 : : */
2804 : 0 : int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2805 : : {
2806 [ # # ]: 0 : if (filp->f_op->lock)
2807 : 0 : return filp->f_op->lock(filp, F_CANCELLK, fl);
2808 : : return 0;
2809 : : }
2810 : : EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2811 : :
2812 : : #ifdef CONFIG_PROC_FS
2813 : : #include <linux/proc_fs.h>
2814 : : #include <linux/seq_file.h>
2815 : :
2816 : : struct locks_iterator {
2817 : : int li_cpu;
2818 : : loff_t li_pos;
2819 : : };
2820 : :
2821 : 0 : static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2822 : : loff_t id, char *pfx)
2823 : : {
2824 : 0 : struct inode *inode = NULL;
2825 : 0 : unsigned int fl_pid;
2826 : 0 : struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
2827 : :
2828 : 0 : fl_pid = locks_translate_pid(fl, proc_pidns);
2829 : : /*
2830 : : * If lock owner is dead (and pid is freed) or not visible in current
2831 : : * pidns, zero is shown as a pid value. Check lock info from
2832 : : * init_pid_ns to get saved lock pid value.
2833 : : */
2834 : :
2835 [ # # ]: 0 : if (fl->fl_file != NULL)
2836 : 0 : inode = locks_inode(fl->fl_file);
2837 : :
2838 : 0 : seq_printf(f, "%lld:%s ", id, pfx);
2839 [ # # ]: 0 : if (IS_POSIX(fl)) {
2840 [ # # ]: 0 : if (fl->fl_flags & FL_ACCESS)
2841 : 0 : seq_puts(f, "ACCESS");
2842 [ # # ]: 0 : else if (IS_OFDLCK(fl))
2843 : 0 : seq_puts(f, "OFDLCK");
2844 : : else
2845 : 0 : seq_puts(f, "POSIX ");
2846 : :
2847 [ # # ]: 0 : seq_printf(f, " %s ",
2848 : : (inode == NULL) ? "*NOINODE*" :
2849 : : mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2850 [ # # ]: 0 : } else if (IS_FLOCK(fl)) {
2851 [ # # ]: 0 : if (fl->fl_type & LOCK_MAND) {
2852 : 0 : seq_puts(f, "FLOCK MSNFS ");
2853 : : } else {
2854 : 0 : seq_puts(f, "FLOCK ADVISORY ");
2855 : : }
2856 [ # # ]: 0 : } else if (IS_LEASE(fl)) {
2857 [ # # ]: 0 : if (fl->fl_flags & FL_DELEG)
2858 : 0 : seq_puts(f, "DELEG ");
2859 : : else
2860 : 0 : seq_puts(f, "LEASE ");
2861 : :
2862 [ # # ]: 0 : if (lease_breaking(fl))
2863 : 0 : seq_puts(f, "BREAKING ");
2864 [ # # ]: 0 : else if (fl->fl_file)
2865 : 0 : seq_puts(f, "ACTIVE ");
2866 : : else
2867 : 0 : seq_puts(f, "BREAKER ");
2868 : : } else {
2869 : 0 : seq_puts(f, "UNKNOWN UNKNOWN ");
2870 : : }
2871 [ # # ]: 0 : if (fl->fl_type & LOCK_MAND) {
2872 [ # # ]: 0 : seq_printf(f, "%s ",
2873 : : (fl->fl_type & LOCK_READ)
2874 [ # # ]: 0 : ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2875 [ # # ]: 0 : : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2876 : : } else {
2877 [ # # ]: 0 : int type = IS_LEASE(fl) ? target_leasetype(fl) : fl->fl_type;
2878 : :
2879 [ # # ]: 0 : seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" :
2880 [ # # ]: 0 : (type == F_RDLCK) ? "READ" : "UNLCK");
2881 : : }
2882 [ # # ]: 0 : if (inode) {
2883 : : /* userspace relies on this representation of dev_t */
2884 : 0 : seq_printf(f, "%d %02x:%02x:%lu ", fl_pid,
2885 : 0 : MAJOR(inode->i_sb->s_dev),
2886 : 0 : MINOR(inode->i_sb->s_dev), inode->i_ino);
2887 : : } else {
2888 : 0 : seq_printf(f, "%d <none>:0 ", fl_pid);
2889 : : }
2890 [ # # ]: 0 : if (IS_POSIX(fl)) {
2891 [ # # ]: 0 : if (fl->fl_end == OFFSET_MAX)
2892 : 0 : seq_printf(f, "%Ld EOF\n", fl->fl_start);
2893 : : else
2894 : 0 : seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2895 : : } else {
2896 : 0 : seq_puts(f, "0 EOF\n");
2897 : : }
2898 : 0 : }
2899 : :
2900 : 0 : static int locks_show(struct seq_file *f, void *v)
2901 : : {
2902 : 0 : struct locks_iterator *iter = f->private;
2903 : 0 : struct file_lock *fl, *bfl;
2904 : 0 : struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
2905 : :
2906 : 0 : fl = hlist_entry(v, struct file_lock, fl_link);
2907 : :
2908 [ # # ]: 0 : if (locks_translate_pid(fl, proc_pidns) == 0)
2909 : : return 0;
2910 : :
2911 : 0 : lock_get_status(f, fl, iter->li_pos, "");
2912 : :
2913 [ # # ]: 0 : list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member)
2914 : 0 : lock_get_status(f, bfl, iter->li_pos, " ->");
2915 : :
2916 : : return 0;
2917 : : }
2918 : :
2919 : 0 : static void __show_fd_locks(struct seq_file *f,
2920 : : struct list_head *head, int *id,
2921 : : struct file *filp, struct files_struct *files)
2922 : : {
2923 : 0 : struct file_lock *fl;
2924 : :
2925 [ # # ]: 0 : list_for_each_entry(fl, head, fl_list) {
2926 : :
2927 [ # # ]: 0 : if (filp != fl->fl_file)
2928 : 0 : continue;
2929 [ # # # # ]: 0 : if (fl->fl_owner != files &&
2930 : : fl->fl_owner != filp)
2931 : 0 : continue;
2932 : :
2933 : 0 : (*id)++;
2934 : 0 : seq_puts(f, "lock:\t");
2935 : 0 : lock_get_status(f, fl, *id, "");
2936 : : }
2937 : 0 : }
2938 : :
2939 : 4680 : void show_fd_locks(struct seq_file *f,
2940 : : struct file *filp, struct files_struct *files)
2941 : : {
2942 : 4680 : struct inode *inode = locks_inode(filp);
2943 : 4680 : struct file_lock_context *ctx;
2944 : 4680 : int id = 0;
2945 : :
2946 : 4680 : ctx = smp_load_acquire(&inode->i_flctx);
2947 [ + - ]: 4680 : if (!ctx)
2948 : 4680 : return;
2949 : :
2950 : 0 : spin_lock(&ctx->flc_lock);
2951 : 0 : __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2952 : 0 : __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2953 : 0 : __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2954 : 0 : spin_unlock(&ctx->flc_lock);
2955 : : }
2956 : :
2957 : 0 : static void *locks_start(struct seq_file *f, loff_t *pos)
2958 : : __acquires(&blocked_lock_lock)
2959 : : {
2960 : 0 : struct locks_iterator *iter = f->private;
2961 : :
2962 : 0 : iter->li_pos = *pos + 1;
2963 : 0 : percpu_down_write(&file_rwsem);
2964 : 0 : spin_lock(&blocked_lock_lock);
2965 : 0 : return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
2966 : : }
2967 : :
2968 : 0 : static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2969 : : {
2970 : 0 : struct locks_iterator *iter = f->private;
2971 : :
2972 : 0 : ++iter->li_pos;
2973 : 0 : return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
2974 : : }
2975 : :
2976 : 0 : static void locks_stop(struct seq_file *f, void *v)
2977 : : __releases(&blocked_lock_lock)
2978 : : {
2979 : 0 : spin_unlock(&blocked_lock_lock);
2980 : 0 : percpu_up_write(&file_rwsem);
2981 : 0 : }
2982 : :
2983 : : static const struct seq_operations locks_seq_operations = {
2984 : : .start = locks_start,
2985 : : .next = locks_next,
2986 : : .stop = locks_stop,
2987 : : .show = locks_show,
2988 : : };
2989 : :
2990 : 78 : static int __init proc_locks_init(void)
2991 : : {
2992 : 78 : proc_create_seq_private("locks", 0, NULL, &locks_seq_operations,
2993 : : sizeof(struct locks_iterator), NULL);
2994 : 78 : return 0;
2995 : : }
2996 : : fs_initcall(proc_locks_init);
2997 : : #endif
2998 : :
2999 : 78 : static int __init filelock_init(void)
3000 : : {
3001 : 78 : int i;
3002 : :
3003 : 78 : flctx_cache = kmem_cache_create("file_lock_ctx",
3004 : : sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
3005 : :
3006 : 78 : filelock_cache = kmem_cache_create("file_lock_cache",
3007 : : sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
3008 : :
3009 [ + + ]: 156 : for_each_possible_cpu(i) {
3010 : 78 : struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
3011 : :
3012 : 78 : spin_lock_init(&fll->lock);
3013 : 78 : INIT_HLIST_HEAD(&fll->hlist);
3014 : : }
3015 : :
3016 : 78 : lease_notifier_chain_init();
3017 : 78 : return 0;
3018 : : }
3019 : : core_initcall(filelock_init);
|
