4 * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
5 * Doug Evans (dje@spiff.uucp), August 07, 1992
7 * Deadlock detection added.
8 * FIXME: one thing isn't handled yet:
9 * - mandatory locks (requires lots of changes elsewhere)
10 * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
12 * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
13 * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
15 * Converted file_lock_table to a linked list from an array, which eliminates
16 * the limits on how many active file locks are open.
17 * Chad Page (pageone@netcom.com), November 27, 1994
19 * Removed dependency on file descriptors. dup()'ed file descriptors now
20 * get the same locks as the original file descriptors, and a close() on
21 * any file descriptor removes ALL the locks on the file for the current
22 * process. Since locks still depend on the process id, locks are inherited
23 * after an exec() but not after a fork(). This agrees with POSIX, and both
24 * BSD and SVR4 practice.
25 * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
27 * Scrapped free list which is redundant now that we allocate locks
28 * dynamically with kmalloc()/kfree().
29 * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
31 * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
33 * FL_POSIX locks are created with calls to fcntl() and lockf() through the
34 * fcntl() system call. They have the semantics described above.
36 * FL_FLOCK locks are created with calls to flock(), through the flock()
37 * system call, which is new. Old C libraries implement flock() via fcntl()
38 * and will continue to use the old, broken implementation.
40 * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
41 * with a file pointer (filp). As a result they can be shared by a parent
42 * process and its children after a fork(). They are removed when the last
43 * file descriptor referring to the file pointer is closed (unless explicitly
46 * FL_FLOCK locks never deadlock, an existing lock is always removed before
47 * upgrading from shared to exclusive (or vice versa). When this happens
48 * any processes blocked by the current lock are woken up and allowed to
49 * run before the new lock is applied.
50 * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
52 * Removed some race conditions in flock_lock_file(), marked other possible
53 * races. Just grep for FIXME to see them.
54 * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
56 * Addressed Dmitry's concerns. Deadlock checking no longer recursive.
57 * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
58 * once we've checked for blocking and deadlocking.
59 * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
61 * Initial implementation of mandatory locks. SunOS turned out to be
62 * a rotten model, so I implemented the "obvious" semantics.
63 * See 'Documentation/filesystems/mandatory-locking.txt' for details.
64 * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
66 * Don't allow mandatory locks on mmap()'ed files. Added simple functions to
67 * check if a file has mandatory locks, used by mmap(), open() and creat() to
68 * see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
70 * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
72 * Tidied up block list handling. Added '/proc/locks' interface.
73 * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
75 * Fixed deadlock condition for pathological code that mixes calls to
76 * flock() and fcntl().
77 * Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
79 * Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
80 * for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
81 * guarantee sensible behaviour in the case where file system modules might
82 * be compiled with different options than the kernel itself.
83 * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
85 * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
86 * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
87 * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
89 * Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
90 * locks. Changed process synchronisation to avoid dereferencing locks that
91 * have already been freed.
92 * Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
94 * Made the block list a circular list to minimise searching in the list.
95 * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
97 * Made mandatory locking a mount option. Default is not to allow mandatory
99 * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
101 * Some adaptations for NFS support.
102 * Olaf Kirch (okir@monad.swb.de), Dec 1996,
104 * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
105 * Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
107 * Use slab allocator instead of kmalloc/kfree.
108 * Use generic list implementation from <linux/list.h>.
109 * Sped up posix_locks_deadlock by only considering blocked locks.
110 * Matthew Wilcox <willy@debian.org>, March, 2000.
112 * Leases and LOCK_MAND
113 * Matthew Wilcox <willy@debian.org>, June, 2000.
114 * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
117 #include <linux/capability.h>
118 #include <linux/file.h>
119 #include <linux/fdtable.h>
120 #include <linux/fs.h>
121 #include <linux/init.h>
122 #include <linux/module.h>
123 #include <linux/security.h>
124 #include <linux/slab.h>
125 #include <linux/syscalls.h>
126 #include <linux/time.h>
127 #include <linux/rcupdate.h>
128 #include <linux/pid_namespace.h>
129 #include <linux/hashtable.h>
130 #include <linux/percpu.h>
131 #include <linux/lglock.h>
133 #define CREATE_TRACE_POINTS
134 #include <trace/events/filelock.h>
136 #include <asm/uaccess.h>
138 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
139 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
140 #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG))
141 #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
143 static bool lease_breaking(struct file_lock *fl)
145 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
148 static int target_leasetype(struct file_lock *fl)
150 if (fl->fl_flags & FL_UNLOCK_PENDING)
152 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
157 int leases_enable = 1;
158 int lease_break_time = 45;
160 #define for_each_lock(inode, lockp) \
161 for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
164 * The global file_lock_list is only used for displaying /proc/locks, so we
165 * keep a list on each CPU, with each list protected by its own spinlock via
166 * the file_lock_lglock. Note that alterations to the list also require that
167 * the relevant i_lock is held.
169 DEFINE_STATIC_LGLOCK(file_lock_lglock);
170 static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
173 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
174 * It is protected by blocked_lock_lock.
176 * We hash locks by lockowner in order to optimize searching for the lock a
177 * particular lockowner is waiting on.
179 * FIXME: make this value scale via some heuristic? We generally will want more
180 * buckets when we have more lockowners holding locks, but that's a little
181 * difficult to determine without knowing what the workload will look like.
183 #define BLOCKED_HASH_BITS 7
184 static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
187 * This lock protects the blocked_hash. Generally, if you're accessing it, you
188 * want to be holding this lock.
190 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
191 * pointer for file_lock structures that are acting as lock requests (in
192 * contrast to those that are acting as records of acquired locks).
194 * Note that when we acquire this lock in order to change the above fields,
195 * we often hold the i_lock as well. In certain cases, when reading the fields
196 * protected by this lock, we can skip acquiring it iff we already hold the
199 * In particular, adding an entry to the fl_block list requires that you hold
200 * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting
201 * an entry from the list however only requires the file_lock_lock.
203 static DEFINE_SPINLOCK(blocked_lock_lock);
205 static struct kmem_cache *flctx_cache __read_mostly;
206 static struct kmem_cache *filelock_cache __read_mostly;
208 static struct file_lock_context *
209 locks_get_lock_context(struct inode *inode)
211 struct file_lock_context *new;
213 if (likely(inode->i_flctx))
216 new = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
220 INIT_LIST_HEAD(&new->flc_flock);
223 * Assign the pointer if it's not already assigned. If it is, then
224 * free the context we just allocated.
226 spin_lock(&inode->i_lock);
227 if (likely(!inode->i_flctx)) {
228 inode->i_flctx = new;
231 spin_unlock(&inode->i_lock);
234 kmem_cache_free(flctx_cache, new);
236 return inode->i_flctx;
240 locks_free_lock_context(struct file_lock_context *ctx)
243 WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
244 kmem_cache_free(flctx_cache, ctx);
248 static void locks_init_lock_heads(struct file_lock *fl)
250 INIT_HLIST_NODE(&fl->fl_link);
251 INIT_LIST_HEAD(&fl->fl_list);
252 INIT_LIST_HEAD(&fl->fl_block);
253 init_waitqueue_head(&fl->fl_wait);
256 /* Allocate an empty lock structure. */
257 struct file_lock *locks_alloc_lock(void)
259 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
262 locks_init_lock_heads(fl);
266 EXPORT_SYMBOL_GPL(locks_alloc_lock);
268 void locks_release_private(struct file_lock *fl)
271 if (fl->fl_ops->fl_release_private)
272 fl->fl_ops->fl_release_private(fl);
277 if (fl->fl_lmops->lm_put_owner)
278 fl->fl_lmops->lm_put_owner(fl);
282 EXPORT_SYMBOL_GPL(locks_release_private);
284 /* Free a lock which is not in use. */
285 void locks_free_lock(struct file_lock *fl)
287 BUG_ON(waitqueue_active(&fl->fl_wait));
288 BUG_ON(!list_empty(&fl->fl_list));
289 BUG_ON(!list_empty(&fl->fl_block));
290 BUG_ON(!hlist_unhashed(&fl->fl_link));
292 locks_release_private(fl);
293 kmem_cache_free(filelock_cache, fl);
295 EXPORT_SYMBOL(locks_free_lock);
298 locks_dispose_list(struct list_head *dispose)
300 struct file_lock *fl;
302 while (!list_empty(dispose)) {
303 fl = list_first_entry(dispose, struct file_lock, fl_list);
304 list_del_init(&fl->fl_list);
309 void locks_init_lock(struct file_lock *fl)
311 memset(fl, 0, sizeof(struct file_lock));
312 locks_init_lock_heads(fl);
315 EXPORT_SYMBOL(locks_init_lock);
318 * Initialize a new lock from an existing file_lock structure.
320 void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
322 new->fl_owner = fl->fl_owner;
323 new->fl_pid = fl->fl_pid;
325 new->fl_flags = fl->fl_flags;
326 new->fl_type = fl->fl_type;
327 new->fl_start = fl->fl_start;
328 new->fl_end = fl->fl_end;
329 new->fl_lmops = fl->fl_lmops;
333 if (fl->fl_lmops->lm_get_owner)
334 fl->fl_lmops->lm_get_owner(new, fl);
337 EXPORT_SYMBOL(locks_copy_conflock);
339 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
341 /* "new" must be a freshly-initialized lock */
342 WARN_ON_ONCE(new->fl_ops);
344 locks_copy_conflock(new, fl);
346 new->fl_file = fl->fl_file;
347 new->fl_ops = fl->fl_ops;
350 if (fl->fl_ops->fl_copy_lock)
351 fl->fl_ops->fl_copy_lock(new, fl);
355 EXPORT_SYMBOL(locks_copy_lock);
357 static inline int flock_translate_cmd(int cmd) {
359 return cmd & (LOCK_MAND | LOCK_RW);
371 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
372 static struct file_lock *
373 flock_make_lock(struct file *filp, unsigned int cmd)
375 struct file_lock *fl;
376 int type = flock_translate_cmd(cmd);
379 return ERR_PTR(type);
381 fl = locks_alloc_lock();
383 return ERR_PTR(-ENOMEM);
387 fl->fl_pid = current->tgid;
388 fl->fl_flags = FL_FLOCK;
390 fl->fl_end = OFFSET_MAX;
395 static int assign_type(struct file_lock *fl, long type)
409 static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
412 switch (l->l_whence) {
417 fl->fl_start = filp->f_pos;
420 fl->fl_start = i_size_read(file_inode(filp));
425 if (l->l_start > OFFSET_MAX - fl->fl_start)
427 fl->fl_start += l->l_start;
428 if (fl->fl_start < 0)
431 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
432 POSIX-2001 defines it. */
434 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
436 fl->fl_end = fl->fl_start + l->l_len - 1;
438 } else if (l->l_len < 0) {
439 if (fl->fl_start + l->l_len < 0)
441 fl->fl_end = fl->fl_start - 1;
442 fl->fl_start += l->l_len;
444 fl->fl_end = OFFSET_MAX;
446 fl->fl_owner = current->files;
447 fl->fl_pid = current->tgid;
449 fl->fl_flags = FL_POSIX;
453 return assign_type(fl, l->l_type);
456 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
459 static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
462 struct flock64 ll = {
464 .l_whence = l->l_whence,
465 .l_start = l->l_start,
469 return flock64_to_posix_lock(filp, fl, &ll);
472 /* default lease lock manager operations */
474 lease_break_callback(struct file_lock *fl)
476 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
481 lease_setup(struct file_lock *fl, void **priv)
483 struct file *filp = fl->fl_file;
484 struct fasync_struct *fa = *priv;
487 * fasync_insert_entry() returns the old entry if any. If there was no
488 * old entry, then it used "priv" and inserted it into the fasync list.
489 * Clear the pointer to indicate that it shouldn't be freed.
491 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
494 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
497 static const struct lock_manager_operations lease_manager_ops = {
498 .lm_break = lease_break_callback,
499 .lm_change = lease_modify,
500 .lm_setup = lease_setup,
504 * Initialize a lease, use the default lock manager operations
506 static int lease_init(struct file *filp, long type, struct file_lock *fl)
508 if (assign_type(fl, type) != 0)
512 fl->fl_pid = current->tgid;
515 fl->fl_flags = FL_LEASE;
517 fl->fl_end = OFFSET_MAX;
519 fl->fl_lmops = &lease_manager_ops;
523 /* Allocate a file_lock initialised to this type of lease */
524 static struct file_lock *lease_alloc(struct file *filp, long type)
526 struct file_lock *fl = locks_alloc_lock();
530 return ERR_PTR(error);
532 error = lease_init(filp, type, fl);
535 return ERR_PTR(error);
540 /* Check if two locks overlap each other.
542 static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
544 return ((fl1->fl_end >= fl2->fl_start) &&
545 (fl2->fl_end >= fl1->fl_start));
549 * Check whether two locks have the same owner.
551 static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
553 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
554 return fl2->fl_lmops == fl1->fl_lmops &&
555 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
556 return fl1->fl_owner == fl2->fl_owner;
559 /* Must be called with the i_lock held! */
560 static void locks_insert_global_locks(struct file_lock *fl)
562 lg_local_lock(&file_lock_lglock);
563 fl->fl_link_cpu = smp_processor_id();
564 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
565 lg_local_unlock(&file_lock_lglock);
568 /* Must be called with the i_lock held! */
569 static void locks_delete_global_locks(struct file_lock *fl)
572 * Avoid taking lock if already unhashed. This is safe since this check
573 * is done while holding the i_lock, and new insertions into the list
574 * also require that it be held.
576 if (hlist_unhashed(&fl->fl_link))
578 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
579 hlist_del_init(&fl->fl_link);
580 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
584 posix_owner_key(struct file_lock *fl)
586 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
587 return fl->fl_lmops->lm_owner_key(fl);
588 return (unsigned long)fl->fl_owner;
591 static void locks_insert_global_blocked(struct file_lock *waiter)
593 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
596 static void locks_delete_global_blocked(struct file_lock *waiter)
598 hash_del(&waiter->fl_link);
601 /* Remove waiter from blocker's block list.
602 * When blocker ends up pointing to itself then the list is empty.
604 * Must be called with blocked_lock_lock held.
606 static void __locks_delete_block(struct file_lock *waiter)
608 locks_delete_global_blocked(waiter);
609 list_del_init(&waiter->fl_block);
610 waiter->fl_next = NULL;
613 static void locks_delete_block(struct file_lock *waiter)
615 spin_lock(&blocked_lock_lock);
616 __locks_delete_block(waiter);
617 spin_unlock(&blocked_lock_lock);
620 /* Insert waiter into blocker's block list.
621 * We use a circular list so that processes can be easily woken up in
622 * the order they blocked. The documentation doesn't require this but
623 * it seems like the reasonable thing to do.
625 * Must be called with both the i_lock and blocked_lock_lock held. The fl_block
626 * list itself is protected by the blocked_lock_lock, but by ensuring that the
627 * i_lock is also held on insertions we can avoid taking the blocked_lock_lock
628 * in some cases when we see that the fl_block list is empty.
630 static void __locks_insert_block(struct file_lock *blocker,
631 struct file_lock *waiter)
633 BUG_ON(!list_empty(&waiter->fl_block));
634 waiter->fl_next = blocker;
635 list_add_tail(&waiter->fl_block, &blocker->fl_block);
636 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
637 locks_insert_global_blocked(waiter);
640 /* Must be called with i_lock held. */
641 static void locks_insert_block(struct file_lock *blocker,
642 struct file_lock *waiter)
644 spin_lock(&blocked_lock_lock);
645 __locks_insert_block(blocker, waiter);
646 spin_unlock(&blocked_lock_lock);
650 * Wake up processes blocked waiting for blocker.
652 * Must be called with the inode->i_lock held!
654 static void locks_wake_up_blocks(struct file_lock *blocker)
657 * Avoid taking global lock if list is empty. This is safe since new
658 * blocked requests are only added to the list under the i_lock, and
659 * the i_lock is always held here. Note that removal from the fl_block
660 * list does not require the i_lock, so we must recheck list_empty()
661 * after acquiring the blocked_lock_lock.
663 if (list_empty(&blocker->fl_block))
666 spin_lock(&blocked_lock_lock);
667 while (!list_empty(&blocker->fl_block)) {
668 struct file_lock *waiter;
670 waiter = list_first_entry(&blocker->fl_block,
671 struct file_lock, fl_block);
672 __locks_delete_block(waiter);
673 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
674 waiter->fl_lmops->lm_notify(waiter);
676 wake_up(&waiter->fl_wait);
678 spin_unlock(&blocked_lock_lock);
681 /* Insert file lock fl into an inode's lock list at the position indicated
682 * by pos. At the same time add the lock to the global file lock list.
684 * Must be called with the i_lock held!
686 static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
688 fl->fl_nspid = get_pid(task_tgid(current));
690 /* insert into file's list */
694 locks_insert_global_locks(fl);
698 locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
700 fl->fl_nspid = get_pid(task_tgid(current));
701 list_add_tail(&fl->fl_list, before);
702 locks_insert_global_locks(fl);
706 * locks_delete_lock - Delete a lock and then free it.
707 * @thisfl_p: pointer that points to the fl_next field of the previous
708 * inode->i_flock list entry
710 * Unlink a lock from all lists and free the namespace reference, but don't
711 * free it yet. Wake up processes that are blocked waiting for this lock and
712 * notify the FS that the lock has been cleared.
714 * Must be called with the i_lock held!
716 static void locks_unlink_lock(struct file_lock **thisfl_p)
718 struct file_lock *fl = *thisfl_p;
720 locks_delete_global_locks(fl);
722 *thisfl_p = fl->fl_next;
726 put_pid(fl->fl_nspid);
730 locks_wake_up_blocks(fl);
734 * Unlink a lock from all lists and free it.
736 * Must be called with i_lock held!
738 static void locks_delete_lock(struct file_lock **thisfl_p,
739 struct list_head *dispose)
741 struct file_lock *fl = *thisfl_p;
743 locks_unlink_lock(thisfl_p);
745 list_add(&fl->fl_list, dispose);
751 locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
753 locks_delete_global_locks(fl);
755 put_pid(fl->fl_nspid);
758 locks_wake_up_blocks(fl);
759 list_move(&fl->fl_list, dispose);
762 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
763 * checks for shared/exclusive status of overlapping locks.
765 static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
767 if (sys_fl->fl_type == F_WRLCK)
769 if (caller_fl->fl_type == F_WRLCK)
774 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
775 * checking before calling the locks_conflict().
777 static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
779 /* POSIX locks owned by the same process do not conflict with
782 if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl))
785 /* Check whether they overlap */
786 if (!locks_overlap(caller_fl, sys_fl))
789 return (locks_conflict(caller_fl, sys_fl));
792 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
793 * checking before calling the locks_conflict().
795 static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
797 /* FLOCK locks referring to the same filp do not conflict with
800 if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
802 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
805 return (locks_conflict(caller_fl, sys_fl));
809 posix_test_lock(struct file *filp, struct file_lock *fl)
811 struct file_lock *cfl;
812 struct inode *inode = file_inode(filp);
814 spin_lock(&inode->i_lock);
815 for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
818 if (posix_locks_conflict(fl, cfl))
822 locks_copy_conflock(fl, cfl);
824 fl->fl_pid = pid_vnr(cfl->fl_nspid);
826 fl->fl_type = F_UNLCK;
827 spin_unlock(&inode->i_lock);
830 EXPORT_SYMBOL(posix_test_lock);
833 * Deadlock detection:
835 * We attempt to detect deadlocks that are due purely to posix file
838 * We assume that a task can be waiting for at most one lock at a time.
839 * So for any acquired lock, the process holding that lock may be
840 * waiting on at most one other lock. That lock in turns may be held by
841 * someone waiting for at most one other lock. Given a requested lock
842 * caller_fl which is about to wait for a conflicting lock block_fl, we
843 * follow this chain of waiters to ensure we are not about to create a
846 * Since we do this before we ever put a process to sleep on a lock, we
847 * are ensured that there is never a cycle; that is what guarantees that
848 * the while() loop in posix_locks_deadlock() eventually completes.
850 * Note: the above assumption may not be true when handling lock
851 * requests from a broken NFS client. It may also fail in the presence
852 * of tasks (such as posix threads) sharing the same open file table.
853 * To handle those cases, we just bail out after a few iterations.
855 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
856 * Because the owner is not even nominally tied to a thread of
857 * execution, the deadlock detection below can't reasonably work well. Just
860 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
861 * locks that just checks for the case where two tasks are attempting to
862 * upgrade from read to write locks on the same inode.
865 #define MAX_DEADLK_ITERATIONS 10
867 /* Find a lock that the owner of the given block_fl is blocking on. */
868 static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
870 struct file_lock *fl;
872 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
873 if (posix_same_owner(fl, block_fl))
879 /* Must be called with the blocked_lock_lock held! */
880 static int posix_locks_deadlock(struct file_lock *caller_fl,
881 struct file_lock *block_fl)
886 * This deadlock detector can't reasonably detect deadlocks with
887 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
889 if (IS_OFDLCK(caller_fl))
892 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
893 if (i++ > MAX_DEADLK_ITERATIONS)
895 if (posix_same_owner(caller_fl, block_fl))
901 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
902 * after any leases, but before any posix locks.
904 * Note that if called with an FL_EXISTS argument, the caller may determine
905 * whether or not a lock was successfully freed by testing the return
908 static int flock_lock_file(struct file *filp, struct file_lock *request)
910 struct file_lock *new_fl = NULL;
911 struct file_lock *fl;
912 struct file_lock_context *ctx;
913 struct inode *inode = file_inode(filp);
918 ctx = locks_get_lock_context(inode);
922 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
923 new_fl = locks_alloc_lock();
928 spin_lock(&inode->i_lock);
929 if (request->fl_flags & FL_ACCESS)
932 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
933 if (filp != fl->fl_file)
935 if (request->fl_type == fl->fl_type)
938 locks_delete_lock_ctx(fl, &dispose);
942 if (request->fl_type == F_UNLCK) {
943 if ((request->fl_flags & FL_EXISTS) && !found)
949 * If a higher-priority process was blocked on the old file lock,
950 * give it the opportunity to lock the file.
953 spin_unlock(&inode->i_lock);
955 spin_lock(&inode->i_lock);
959 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
960 if (!flock_locks_conflict(request, fl))
963 if (!(request->fl_flags & FL_SLEEP))
965 error = FILE_LOCK_DEFERRED;
966 locks_insert_block(fl, request);
969 if (request->fl_flags & FL_ACCESS)
971 locks_copy_lock(new_fl, request);
972 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
977 spin_unlock(&inode->i_lock);
979 locks_free_lock(new_fl);
980 locks_dispose_list(&dispose);
984 static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
986 struct file_lock *fl;
987 struct file_lock *new_fl = NULL;
988 struct file_lock *new_fl2 = NULL;
989 struct file_lock *left = NULL;
990 struct file_lock *right = NULL;
991 struct file_lock **before;
997 * We may need two file_lock structures for this operation,
998 * so we get them in advance to avoid races.
1000 * In some cases we can be sure, that no new locks will be needed
1002 if (!(request->fl_flags & FL_ACCESS) &&
1003 (request->fl_type != F_UNLCK ||
1004 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1005 new_fl = locks_alloc_lock();
1006 new_fl2 = locks_alloc_lock();
1009 spin_lock(&inode->i_lock);
1011 * New lock request. Walk all POSIX locks and look for conflicts. If
1012 * there are any, either return error or put the request on the
1013 * blocker's list of waiters and the global blocked_hash.
1015 if (request->fl_type != F_UNLCK) {
1016 for_each_lock(inode, before) {
1020 if (!posix_locks_conflict(request, fl))
1023 locks_copy_conflock(conflock, fl);
1025 if (!(request->fl_flags & FL_SLEEP))
1028 * Deadlock detection and insertion into the blocked
1029 * locks list must be done while holding the same lock!
1032 spin_lock(&blocked_lock_lock);
1033 if (likely(!posix_locks_deadlock(request, fl))) {
1034 error = FILE_LOCK_DEFERRED;
1035 __locks_insert_block(fl, request);
1037 spin_unlock(&blocked_lock_lock);
1042 /* If we're just looking for a conflict, we're done. */
1044 if (request->fl_flags & FL_ACCESS)
1048 * Find the first old lock with the same owner as the new lock.
1051 before = &inode->i_flock;
1053 /* First skip locks owned by other processes. */
1054 while ((fl = *before) && (!IS_POSIX(fl) ||
1055 !posix_same_owner(request, fl))) {
1056 before = &fl->fl_next;
1059 /* Process locks with this owner. */
1060 while ((fl = *before) && posix_same_owner(request, fl)) {
1061 /* Detect adjacent or overlapping regions (if same lock type)
1063 if (request->fl_type == fl->fl_type) {
1064 /* In all comparisons of start vs end, use
1065 * "start - 1" rather than "end + 1". If end
1066 * is OFFSET_MAX, end + 1 will become negative.
1068 if (fl->fl_end < request->fl_start - 1)
1070 /* If the next lock in the list has entirely bigger
1071 * addresses than the new one, insert the lock here.
1073 if (fl->fl_start - 1 > request->fl_end)
1076 /* If we come here, the new and old lock are of the
1077 * same type and adjacent or overlapping. Make one
1078 * lock yielding from the lower start address of both
1079 * locks to the higher end address.
1081 if (fl->fl_start > request->fl_start)
1082 fl->fl_start = request->fl_start;
1084 request->fl_start = fl->fl_start;
1085 if (fl->fl_end < request->fl_end)
1086 fl->fl_end = request->fl_end;
1088 request->fl_end = fl->fl_end;
1090 locks_delete_lock(before, &dispose);
1097 /* Processing for different lock types is a bit
1100 if (fl->fl_end < request->fl_start)
1102 if (fl->fl_start > request->fl_end)
1104 if (request->fl_type == F_UNLCK)
1106 if (fl->fl_start < request->fl_start)
1108 /* If the next lock in the list has a higher end
1109 * address than the new one, insert the new one here.
1111 if (fl->fl_end > request->fl_end) {
1115 if (fl->fl_start >= request->fl_start) {
1116 /* The new lock completely replaces an old
1117 * one (This may happen several times).
1120 locks_delete_lock(before, &dispose);
1124 * Replace the old lock with new_fl, and
1125 * remove the old one. It's safe to do the
1126 * insert here since we know that we won't be
1127 * using new_fl later, and that the lock is
1128 * just replacing an existing lock.
1133 locks_copy_lock(new_fl, request);
1136 locks_delete_lock(before, &dispose);
1137 locks_insert_lock(before, request);
1141 /* Go on to next lock.
1144 before = &fl->fl_next;
1148 * The above code only modifies existing locks in case of merging or
1149 * replacing. If new lock(s) need to be inserted all modifications are
1150 * done below this, so it's safe yet to bail out.
1152 error = -ENOLCK; /* "no luck" */
1153 if (right && left == right && !new_fl2)
1158 if (request->fl_type == F_UNLCK) {
1159 if (request->fl_flags & FL_EXISTS)
1168 locks_copy_lock(new_fl, request);
1169 locks_insert_lock(before, new_fl);
1173 if (left == right) {
1174 /* The new lock breaks the old one in two pieces,
1175 * so we have to use the second new lock.
1179 locks_copy_lock(left, right);
1180 locks_insert_lock(before, left);
1182 right->fl_start = request->fl_end + 1;
1183 locks_wake_up_blocks(right);
1186 left->fl_end = request->fl_start - 1;
1187 locks_wake_up_blocks(left);
1190 spin_unlock(&inode->i_lock);
1192 * Free any unused locks.
1195 locks_free_lock(new_fl);
1197 locks_free_lock(new_fl2);
1198 locks_dispose_list(&dispose);
1203 * posix_lock_file - Apply a POSIX-style lock to a file
1204 * @filp: The file to apply the lock to
1205 * @fl: The lock to be applied
1206 * @conflock: Place to return a copy of the conflicting lock, if found.
1208 * Add a POSIX style lock to a file.
1209 * We merge adjacent & overlapping locks whenever possible.
1210 * POSIX locks are sorted by owner task, then by starting address
1212 * Note that if called with an FL_EXISTS argument, the caller may determine
1213 * whether or not a lock was successfully freed by testing the return
1214 * value for -ENOENT.
1216 int posix_lock_file(struct file *filp, struct file_lock *fl,
1217 struct file_lock *conflock)
1219 return __posix_lock_file(file_inode(filp), fl, conflock);
1221 EXPORT_SYMBOL(posix_lock_file);
1224 * posix_lock_file_wait - Apply a POSIX-style lock to a file
1225 * @filp: The file to apply the lock to
1226 * @fl: The lock to be applied
1228 * Add a POSIX style lock to a file.
1229 * We merge adjacent & overlapping locks whenever possible.
1230 * POSIX locks are sorted by owner task, then by starting address
1232 int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1237 error = posix_lock_file(filp, fl, NULL);
1238 if (error != FILE_LOCK_DEFERRED)
1240 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1244 locks_delete_block(fl);
1249 EXPORT_SYMBOL(posix_lock_file_wait);
1252 * locks_mandatory_locked - Check for an active lock
1253 * @file: the file to check
1255 * Searches the inode's list of locks to find any POSIX locks which conflict.
1256 * This function is called from locks_verify_locked() only.
1258 int locks_mandatory_locked(struct file *file)
1260 struct inode *inode = file_inode(file);
1261 struct file_lock *fl;
1264 * Search the lock list for this inode for any POSIX locks.
1266 spin_lock(&inode->i_lock);
1267 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
1270 if (fl->fl_owner != current->files &&
1271 fl->fl_owner != file)
1274 spin_unlock(&inode->i_lock);
1275 return fl ? -EAGAIN : 0;
1279 * locks_mandatory_area - Check for a conflicting lock
1280 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1282 * @inode: the file to check
1283 * @filp: how the file was opened (if it was)
1284 * @offset: start of area to check
1285 * @count: length of area to check
1287 * Searches the inode's list of locks to find any POSIX locks which conflict.
1288 * This function is called from rw_verify_area() and
1289 * locks_verify_truncate().
1291 int locks_mandatory_area(int read_write, struct inode *inode,
1292 struct file *filp, loff_t offset,
1295 struct file_lock fl;
1299 locks_init_lock(&fl);
1300 fl.fl_pid = current->tgid;
1302 fl.fl_flags = FL_POSIX | FL_ACCESS;
1303 if (filp && !(filp->f_flags & O_NONBLOCK))
1305 fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1306 fl.fl_start = offset;
1307 fl.fl_end = offset + count - 1;
1312 fl.fl_flags &= ~FL_SLEEP;
1313 error = __posix_lock_file(inode, &fl, NULL);
1319 fl.fl_flags |= FL_SLEEP;
1320 fl.fl_owner = current->files;
1321 error = __posix_lock_file(inode, &fl, NULL);
1322 if (error != FILE_LOCK_DEFERRED)
1324 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1327 * If we've been sleeping someone might have
1328 * changed the permissions behind our back.
1330 if (__mandatory_lock(inode))
1334 locks_delete_block(&fl);
1341 EXPORT_SYMBOL(locks_mandatory_area);
1343 static void lease_clear_pending(struct file_lock *fl, int arg)
1347 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1350 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1354 /* We already had a lease on this file; just change its type */
1355 int lease_modify(struct file_lock **before, int arg, struct list_head *dispose)
1357 struct file_lock *fl = *before;
1358 int error = assign_type(fl, arg);
1362 lease_clear_pending(fl, arg);
1363 locks_wake_up_blocks(fl);
1364 if (arg == F_UNLCK) {
1365 struct file *filp = fl->fl_file;
1368 filp->f_owner.signum = 0;
1369 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1370 if (fl->fl_fasync != NULL) {
1371 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1372 fl->fl_fasync = NULL;
1374 locks_delete_lock(before, dispose);
1378 EXPORT_SYMBOL(lease_modify);
1380 static bool past_time(unsigned long then)
1383 /* 0 is a special value meaning "this never expires": */
1385 return time_after(jiffies, then);
1388 static void time_out_leases(struct inode *inode, struct list_head *dispose)
1390 struct file_lock **before;
1391 struct file_lock *fl;
1393 lockdep_assert_held(&inode->i_lock);
1395 before = &inode->i_flock;
1396 while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {
1397 trace_time_out_leases(inode, fl);
1398 if (past_time(fl->fl_downgrade_time))
1399 lease_modify(before, F_RDLCK, dispose);
1400 if (past_time(fl->fl_break_time))
1401 lease_modify(before, F_UNLCK, dispose);
1402 if (fl == *before) /* lease_modify may have freed fl */
1403 before = &fl->fl_next;
1407 static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1409 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1411 return locks_conflict(breaker, lease);
1415 any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1417 struct file_lock *fl;
1419 lockdep_assert_held(&inode->i_lock);
1421 for (fl = inode->i_flock ; fl && IS_LEASE(fl); fl = fl->fl_next) {
1422 if (leases_conflict(fl, breaker))
1429 * __break_lease - revoke all outstanding leases on file
1430 * @inode: the inode of the file to return
1431 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1433 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1436 * break_lease (inlined for speed) has checked there already is at least
1437 * some kind of lock (maybe a lease) on this file. Leases are broken on
1438 * a call to open() or truncate(). This function can sleep unless you
1439 * specified %O_NONBLOCK to your open().
1441 int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1444 struct file_lock *new_fl;
1445 struct file_lock *fl, **before;
1446 unsigned long break_time;
1447 int want_write = (mode & O_ACCMODE) != O_RDONLY;
1450 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1452 return PTR_ERR(new_fl);
1453 new_fl->fl_flags = type;
1455 spin_lock(&inode->i_lock);
1457 time_out_leases(inode, &dispose);
1459 if (!any_leases_conflict(inode, new_fl))
1463 if (lease_break_time > 0) {
1464 break_time = jiffies + lease_break_time * HZ;
1465 if (break_time == 0)
1466 break_time++; /* so that 0 means no break time */
1469 for (before = &inode->i_flock;
1470 ((fl = *before) != NULL) && IS_LEASE(fl);
1471 before = &fl->fl_next) {
1472 if (!leases_conflict(fl, new_fl))
1475 if (fl->fl_flags & FL_UNLOCK_PENDING)
1477 fl->fl_flags |= FL_UNLOCK_PENDING;
1478 fl->fl_break_time = break_time;
1480 if (lease_breaking(inode->i_flock))
1482 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1483 fl->fl_downgrade_time = break_time;
1485 if (fl->fl_lmops->lm_break(fl))
1486 locks_delete_lock(before, &dispose);
1489 fl = inode->i_flock;
1490 if (!fl || !IS_LEASE(fl))
1493 if (mode & O_NONBLOCK) {
1494 trace_break_lease_noblock(inode, new_fl);
1495 error = -EWOULDBLOCK;
1500 break_time = inode->i_flock->fl_break_time;
1501 if (break_time != 0)
1502 break_time -= jiffies;
1503 if (break_time == 0)
1505 locks_insert_block(inode->i_flock, new_fl);
1506 trace_break_lease_block(inode, new_fl);
1507 spin_unlock(&inode->i_lock);
1508 locks_dispose_list(&dispose);
1509 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1510 !new_fl->fl_next, break_time);
1511 spin_lock(&inode->i_lock);
1512 trace_break_lease_unblock(inode, new_fl);
1513 locks_delete_block(new_fl);
1516 * Wait for the next conflicting lease that has not been
1520 time_out_leases(inode, &dispose);
1521 if (any_leases_conflict(inode, new_fl))
1528 spin_unlock(&inode->i_lock);
1529 locks_dispose_list(&dispose);
1530 locks_free_lock(new_fl);
1534 EXPORT_SYMBOL(__break_lease);
1537 * lease_get_mtime - get the last modified time of an inode
1539 * @time: pointer to a timespec which will contain the last modified time
1541 * This is to force NFS clients to flush their caches for files with
1542 * exclusive leases. The justification is that if someone has an
1543 * exclusive lease, then they could be modifying it.
1545 void lease_get_mtime(struct inode *inode, struct timespec *time)
1547 bool has_lease = false;
1548 struct file_lock *flock;
1550 if (inode->i_flock) {
1551 spin_lock(&inode->i_lock);
1552 flock = inode->i_flock;
1553 if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK))
1555 spin_unlock(&inode->i_lock);
1559 *time = current_fs_time(inode->i_sb);
1561 *time = inode->i_mtime;
1564 EXPORT_SYMBOL(lease_get_mtime);
1567 * fcntl_getlease - Enquire what lease is currently active
1570 * The value returned by this function will be one of
1571 * (if no lease break is pending):
1573 * %F_RDLCK to indicate a shared lease is held.
1575 * %F_WRLCK to indicate an exclusive lease is held.
1577 * %F_UNLCK to indicate no lease is held.
1579 * (if a lease break is pending):
1581 * %F_RDLCK to indicate an exclusive lease needs to be
1582 * changed to a shared lease (or removed).
1584 * %F_UNLCK to indicate the lease needs to be removed.
1586 * XXX: sfr & willy disagree over whether F_INPROGRESS
1587 * should be returned to userspace.
1589 int fcntl_getlease(struct file *filp)
1591 struct file_lock *fl;
1592 struct inode *inode = file_inode(filp);
1596 spin_lock(&inode->i_lock);
1597 time_out_leases(file_inode(filp), &dispose);
1598 for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);
1600 if (fl->fl_file == filp) {
1601 type = target_leasetype(fl);
1605 spin_unlock(&inode->i_lock);
1606 locks_dispose_list(&dispose);
1611 * check_conflicting_open - see if the given dentry points to a file that has
1612 * an existing open that would conflict with the
1614 * @dentry: dentry to check
1615 * @arg: type of lease that we're trying to acquire
1617 * Check to see if there's an existing open fd on this file that would
1618 * conflict with the lease we're trying to set.
1621 check_conflicting_open(const struct dentry *dentry, const long arg)
1624 struct inode *inode = dentry->d_inode;
1626 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1629 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1630 (atomic_read(&inode->i_count) > 1)))
1637 generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1639 struct file_lock *fl, **before, **my_before = NULL, *lease;
1640 struct dentry *dentry = filp->f_path.dentry;
1641 struct inode *inode = dentry->d_inode;
1642 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1647 trace_generic_add_lease(inode, lease);
1650 * In the delegation case we need mutual exclusion with
1651 * a number of operations that take the i_mutex. We trylock
1652 * because delegations are an optional optimization, and if
1653 * there's some chance of a conflict--we'd rather not
1654 * bother, maybe that's a sign this just isn't a good file to
1655 * hand out a delegation on.
1657 if (is_deleg && !mutex_trylock(&inode->i_mutex))
1660 if (is_deleg && arg == F_WRLCK) {
1661 /* Write delegations are not currently supported: */
1662 mutex_unlock(&inode->i_mutex);
1667 spin_lock(&inode->i_lock);
1668 time_out_leases(inode, &dispose);
1669 error = check_conflicting_open(dentry, arg);
1674 * At this point, we know that if there is an exclusive
1675 * lease on this file, then we hold it on this filp
1676 * (otherwise our open of this file would have blocked).
1677 * And if we are trying to acquire an exclusive lease,
1678 * then the file is not open by anyone (including us)
1679 * except for this filp.
1682 for (before = &inode->i_flock;
1683 ((fl = *before) != NULL) && IS_LEASE(fl);
1684 before = &fl->fl_next) {
1685 if (fl->fl_file == filp) {
1690 * No exclusive leases if someone else has a lease on
1696 * Modifying our existing lease is OK, but no getting a
1697 * new lease if someone else is opening for write:
1699 if (fl->fl_flags & FL_UNLOCK_PENDING)
1703 if (my_before != NULL) {
1705 error = lease->fl_lmops->lm_change(my_before, arg, &dispose);
1715 locks_insert_lock(before, lease);
1717 * The check in break_lease() is lockless. It's possible for another
1718 * open to race in after we did the earlier check for a conflicting
1719 * open but before the lease was inserted. Check again for a
1720 * conflicting open and cancel the lease if there is one.
1722 * We also add a barrier here to ensure that the insertion of the lock
1723 * precedes these checks.
1726 error = check_conflicting_open(dentry, arg);
1731 if (lease->fl_lmops->lm_setup)
1732 lease->fl_lmops->lm_setup(lease, priv);
1734 spin_unlock(&inode->i_lock);
1735 locks_dispose_list(&dispose);
1737 mutex_unlock(&inode->i_mutex);
1738 if (!error && !my_before)
1742 locks_unlink_lock(before);
1746 static int generic_delete_lease(struct file *filp)
1748 int error = -EAGAIN;
1749 struct file_lock *fl, **before;
1750 struct dentry *dentry = filp->f_path.dentry;
1751 struct inode *inode = dentry->d_inode;
1754 spin_lock(&inode->i_lock);
1755 time_out_leases(inode, &dispose);
1756 for (before = &inode->i_flock;
1757 ((fl = *before) != NULL) && IS_LEASE(fl);
1758 before = &fl->fl_next) {
1759 if (fl->fl_file == filp)
1762 trace_generic_delete_lease(inode, fl);
1763 if (fl && IS_LEASE(fl))
1764 error = fl->fl_lmops->lm_change(before, F_UNLCK, &dispose);
1765 spin_unlock(&inode->i_lock);
1766 locks_dispose_list(&dispose);
1771 * generic_setlease - sets a lease on an open file
1772 * @filp: file pointer
1773 * @arg: type of lease to obtain
1774 * @flp: input - file_lock to use, output - file_lock inserted
1775 * @priv: private data for lm_setup (may be NULL if lm_setup
1776 * doesn't require it)
1778 * The (input) flp->fl_lmops->lm_break function is required
1781 int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1784 struct dentry *dentry = filp->f_path.dentry;
1785 struct inode *inode = dentry->d_inode;
1788 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1790 if (!S_ISREG(inode->i_mode))
1792 error = security_file_lock(filp, arg);
1798 return generic_delete_lease(filp);
1801 if (!(*flp)->fl_lmops->lm_break) {
1805 return generic_add_lease(filp, arg, flp, priv);
1810 EXPORT_SYMBOL(generic_setlease);
1813 * vfs_setlease - sets a lease on an open file
1814 * @filp: file pointer
1815 * @arg: type of lease to obtain
1816 * @lease: file_lock to use when adding a lease
1817 * @priv: private info for lm_setup when adding a lease (may be
1818 * NULL if lm_setup doesn't require it)
1820 * Call this to establish a lease on the file. The "lease" argument is not
1821 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1822 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1823 * if not, this function will return -ENOLCK (and generate a scary-looking
1826 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1827 * may be NULL if the lm_setup operation doesn't require it.
1830 vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
1832 if (filp->f_op->setlease)
1833 return filp->f_op->setlease(filp, arg, lease, priv);
1835 return generic_setlease(filp, arg, lease, priv);
1837 EXPORT_SYMBOL_GPL(vfs_setlease);
1839 static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
1841 struct file_lock *fl;
1842 struct fasync_struct *new;
1845 fl = lease_alloc(filp, arg);
1849 new = fasync_alloc();
1851 locks_free_lock(fl);
1856 error = vfs_setlease(filp, arg, &fl, (void **)&new);
1858 locks_free_lock(fl);
1865 * fcntl_setlease - sets a lease on an open file
1866 * @fd: open file descriptor
1867 * @filp: file pointer
1868 * @arg: type of lease to obtain
1870 * Call this fcntl to establish a lease on the file.
1871 * Note that you also need to call %F_SETSIG to
1872 * receive a signal when the lease is broken.
1874 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1877 return vfs_setlease(filp, F_UNLCK, NULL, NULL);
1878 return do_fcntl_add_lease(fd, filp, arg);
1882 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1883 * @filp: The file to apply the lock to
1884 * @fl: The lock to be applied
1886 * Add a FLOCK style lock to a file.
1888 int flock_lock_file_wait(struct file *filp, struct file_lock *fl)
1893 error = flock_lock_file(filp, fl);
1894 if (error != FILE_LOCK_DEFERRED)
1896 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1900 locks_delete_block(fl);
1906 EXPORT_SYMBOL(flock_lock_file_wait);
1909 * sys_flock: - flock() system call.
1910 * @fd: the file descriptor to lock.
1911 * @cmd: the type of lock to apply.
1913 * Apply a %FL_FLOCK style lock to an open file descriptor.
1914 * The @cmd can be one of
1916 * %LOCK_SH -- a shared lock.
1918 * %LOCK_EX -- an exclusive lock.
1920 * %LOCK_UN -- remove an existing lock.
1922 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1924 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1925 * processes read and write access respectively.
1927 SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
1929 struct fd f = fdget(fd);
1930 struct file_lock *lock;
1931 int can_sleep, unlock;
1938 can_sleep = !(cmd & LOCK_NB);
1940 unlock = (cmd == LOCK_UN);
1942 if (!unlock && !(cmd & LOCK_MAND) &&
1943 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
1946 lock = flock_make_lock(f.file, cmd);
1948 error = PTR_ERR(lock);
1953 lock->fl_flags |= FL_SLEEP;
1955 error = security_file_lock(f.file, lock->fl_type);
1959 if (f.file->f_op->flock)
1960 error = f.file->f_op->flock(f.file,
1961 (can_sleep) ? F_SETLKW : F_SETLK,
1964 error = flock_lock_file_wait(f.file, lock);
1967 locks_free_lock(lock);
1976 * vfs_test_lock - test file byte range lock
1977 * @filp: The file to test lock for
1978 * @fl: The lock to test; also used to hold result
1980 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1981 * setting conf->fl_type to something other than F_UNLCK.
1983 int vfs_test_lock(struct file *filp, struct file_lock *fl)
1985 if (filp->f_op->lock)
1986 return filp->f_op->lock(filp, F_GETLK, fl);
1987 posix_test_lock(filp, fl);
1990 EXPORT_SYMBOL_GPL(vfs_test_lock);
1992 static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
1994 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
1995 #if BITS_PER_LONG == 32
1997 * Make sure we can represent the posix lock via
1998 * legacy 32bit flock.
2000 if (fl->fl_start > OFFT_OFFSET_MAX)
2002 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2005 flock->l_start = fl->fl_start;
2006 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2007 fl->fl_end - fl->fl_start + 1;
2008 flock->l_whence = 0;
2009 flock->l_type = fl->fl_type;
2013 #if BITS_PER_LONG == 32
2014 static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2016 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
2017 flock->l_start = fl->fl_start;
2018 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2019 fl->fl_end - fl->fl_start + 1;
2020 flock->l_whence = 0;
2021 flock->l_type = fl->fl_type;
2025 /* Report the first existing lock that would conflict with l.
2026 * This implements the F_GETLK command of fcntl().
2028 int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
2030 struct file_lock file_lock;
2035 if (copy_from_user(&flock, l, sizeof(flock)))
2038 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2041 error = flock_to_posix_lock(filp, &file_lock, &flock);
2045 if (cmd == F_OFD_GETLK) {
2047 if (flock.l_pid != 0)
2051 file_lock.fl_flags |= FL_OFDLCK;
2052 file_lock.fl_owner = filp;
2055 error = vfs_test_lock(filp, &file_lock);
2059 flock.l_type = file_lock.fl_type;
2060 if (file_lock.fl_type != F_UNLCK) {
2061 error = posix_lock_to_flock(&flock, &file_lock);
2066 if (!copy_to_user(l, &flock, sizeof(flock)))
2069 locks_release_private(&file_lock);
2075 * vfs_lock_file - file byte range lock
2076 * @filp: The file to apply the lock to
2077 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2078 * @fl: The lock to be applied
2079 * @conf: Place to return a copy of the conflicting lock, if found.
2081 * A caller that doesn't care about the conflicting lock may pass NULL
2082 * as the final argument.
2084 * If the filesystem defines a private ->lock() method, then @conf will
2085 * be left unchanged; so a caller that cares should initialize it to
2086 * some acceptable default.
2088 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2089 * locks, the ->lock() interface may return asynchronously, before the lock has
2090 * been granted or denied by the underlying filesystem, if (and only if)
2091 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2092 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2093 * the request is for a blocking lock. When ->lock() does return asynchronously,
2094 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2095 * request completes.
2096 * If the request is for non-blocking lock the file system should return
2097 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2098 * with the result. If the request timed out the callback routine will return a
2099 * nonzero return code and the file system should release the lock. The file
2100 * system is also responsible to keep a corresponding posix lock when it
2101 * grants a lock so the VFS can find out which locks are locally held and do
2102 * the correct lock cleanup when required.
2103 * The underlying filesystem must not drop the kernel lock or call
2104 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2107 int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2109 if (filp->f_op->lock)
2110 return filp->f_op->lock(filp, cmd, fl);
2112 return posix_lock_file(filp, fl, conf);
2114 EXPORT_SYMBOL_GPL(vfs_lock_file);
2116 static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2117 struct file_lock *fl)
2121 error = security_file_lock(filp, fl->fl_type);
2126 error = vfs_lock_file(filp, cmd, fl, NULL);
2127 if (error != FILE_LOCK_DEFERRED)
2129 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2133 locks_delete_block(fl);
2140 /* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
2142 check_fmode_for_setlk(struct file_lock *fl)
2144 switch (fl->fl_type) {
2146 if (!(fl->fl_file->f_mode & FMODE_READ))
2150 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2156 /* Apply the lock described by l to an open file descriptor.
2157 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2159 int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2160 struct flock __user *l)
2162 struct file_lock *file_lock = locks_alloc_lock();
2164 struct inode *inode;
2168 if (file_lock == NULL)
2172 * This might block, so we do it before checking the inode.
2175 if (copy_from_user(&flock, l, sizeof(flock)))
2178 inode = file_inode(filp);
2180 /* Don't allow mandatory locks on files that may be memory mapped
2183 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2189 error = flock_to_posix_lock(filp, file_lock, &flock);
2193 error = check_fmode_for_setlk(file_lock);
2198 * If the cmd is requesting file-private locks, then set the
2199 * FL_OFDLCK flag and override the owner.
2204 if (flock.l_pid != 0)
2208 file_lock->fl_flags |= FL_OFDLCK;
2209 file_lock->fl_owner = filp;
2213 if (flock.l_pid != 0)
2217 file_lock->fl_flags |= FL_OFDLCK;
2218 file_lock->fl_owner = filp;
2221 file_lock->fl_flags |= FL_SLEEP;
2224 error = do_lock_file_wait(filp, cmd, file_lock);
2227 * Attempt to detect a close/fcntl race and recover by
2228 * releasing the lock that was just acquired.
2231 * we need that spin_lock here - it prevents reordering between
2232 * update of inode->i_flock and check for it done in close().
2233 * rcu_read_lock() wouldn't do.
2235 spin_lock(¤t->files->file_lock);
2237 spin_unlock(¤t->files->file_lock);
2238 if (!error && f != filp && flock.l_type != F_UNLCK) {
2239 flock.l_type = F_UNLCK;
2244 locks_free_lock(file_lock);
2248 #if BITS_PER_LONG == 32
2249 /* Report the first existing lock that would conflict with l.
2250 * This implements the F_GETLK command of fcntl().
2252 int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
2254 struct file_lock file_lock;
2255 struct flock64 flock;
2259 if (copy_from_user(&flock, l, sizeof(flock)))
2262 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2265 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2269 if (cmd == F_OFD_GETLK) {
2271 if (flock.l_pid != 0)
2275 file_lock.fl_flags |= FL_OFDLCK;
2276 file_lock.fl_owner = filp;
2279 error = vfs_test_lock(filp, &file_lock);
2283 flock.l_type = file_lock.fl_type;
2284 if (file_lock.fl_type != F_UNLCK)
2285 posix_lock_to_flock64(&flock, &file_lock);
2288 if (!copy_to_user(l, &flock, sizeof(flock)))
2291 locks_release_private(&file_lock);
2296 /* Apply the lock described by l to an open file descriptor.
2297 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2299 int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2300 struct flock64 __user *l)
2302 struct file_lock *file_lock = locks_alloc_lock();
2303 struct flock64 flock;
2304 struct inode *inode;
2308 if (file_lock == NULL)
2312 * This might block, so we do it before checking the inode.
2315 if (copy_from_user(&flock, l, sizeof(flock)))
2318 inode = file_inode(filp);
2320 /* Don't allow mandatory locks on files that may be memory mapped
2323 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2329 error = flock64_to_posix_lock(filp, file_lock, &flock);
2333 error = check_fmode_for_setlk(file_lock);
2338 * If the cmd is requesting file-private locks, then set the
2339 * FL_OFDLCK flag and override the owner.
2344 if (flock.l_pid != 0)
2348 file_lock->fl_flags |= FL_OFDLCK;
2349 file_lock->fl_owner = filp;
2353 if (flock.l_pid != 0)
2357 file_lock->fl_flags |= FL_OFDLCK;
2358 file_lock->fl_owner = filp;
2361 file_lock->fl_flags |= FL_SLEEP;
2364 error = do_lock_file_wait(filp, cmd, file_lock);
2367 * Attempt to detect a close/fcntl race and recover by
2368 * releasing the lock that was just acquired.
2370 spin_lock(¤t->files->file_lock);
2372 spin_unlock(¤t->files->file_lock);
2373 if (!error && f != filp && flock.l_type != F_UNLCK) {
2374 flock.l_type = F_UNLCK;
2379 locks_free_lock(file_lock);
2382 #endif /* BITS_PER_LONG == 32 */
2385 * This function is called when the file is being removed
2386 * from the task's fd array. POSIX locks belonging to this task
2387 * are deleted at this time.
2389 void locks_remove_posix(struct file *filp, fl_owner_t owner)
2391 struct file_lock lock;
2394 * If there are no locks held on this file, we don't need to call
2395 * posix_lock_file(). Another process could be setting a lock on this
2396 * file at the same time, but we wouldn't remove that lock anyway.
2398 if (!file_inode(filp)->i_flock)
2401 lock.fl_type = F_UNLCK;
2402 lock.fl_flags = FL_POSIX | FL_CLOSE;
2404 lock.fl_end = OFFSET_MAX;
2405 lock.fl_owner = owner;
2406 lock.fl_pid = current->tgid;
2407 lock.fl_file = filp;
2409 lock.fl_lmops = NULL;
2411 vfs_lock_file(filp, F_SETLK, &lock, NULL);
2413 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2414 lock.fl_ops->fl_release_private(&lock);
2417 EXPORT_SYMBOL(locks_remove_posix);
2420 locks_remove_flock(struct file *filp)
2422 struct file_lock fl = {
2424 .fl_pid = current->tgid,
2426 .fl_flags = FL_FLOCK,
2428 .fl_end = OFFSET_MAX,
2430 struct file_lock_context *flctx = file_inode(filp)->i_flctx;
2432 if (!flctx || list_empty(&flctx->flc_flock))
2435 if (filp->f_op->flock)
2436 filp->f_op->flock(filp, F_SETLKW, &fl);
2438 flock_lock_file(filp, &fl);
2440 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2441 fl.fl_ops->fl_release_private(&fl);
2445 * This function is called on the last close of an open file.
2447 void locks_remove_file(struct file *filp)
2449 struct inode * inode = file_inode(filp);
2450 struct file_lock *fl;
2451 struct file_lock **before;
2454 /* remove any OFD locks */
2455 locks_remove_posix(filp, filp);
2457 /* remove flock locks */
2458 locks_remove_flock(filp);
2460 if (!inode->i_flock)
2463 spin_lock(&inode->i_lock);
2464 before = &inode->i_flock;
2466 while ((fl = *before) != NULL) {
2467 if (fl->fl_file == filp) {
2469 lease_modify(before, F_UNLCK, &dispose);
2474 * There's a leftover lock on the list of a type that
2475 * we didn't expect to see. Most likely a classic
2476 * POSIX lock that ended up not getting released
2477 * properly, or that raced onto the list somehow. Log
2478 * some info about it and then just remove it from
2481 WARN(1, "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n",
2482 MAJOR(inode->i_sb->s_dev),
2483 MINOR(inode->i_sb->s_dev), inode->i_ino,
2484 fl->fl_type, fl->fl_flags,
2485 fl->fl_start, fl->fl_end);
2487 locks_delete_lock(before, &dispose);
2490 before = &fl->fl_next;
2492 spin_unlock(&inode->i_lock);
2493 locks_dispose_list(&dispose);
2497 * posix_unblock_lock - stop waiting for a file lock
2498 * @waiter: the lock which was waiting
2500 * lockd needs to block waiting for locks.
2503 posix_unblock_lock(struct file_lock *waiter)
2507 spin_lock(&blocked_lock_lock);
2508 if (waiter->fl_next)
2509 __locks_delete_block(waiter);
2512 spin_unlock(&blocked_lock_lock);
2515 EXPORT_SYMBOL(posix_unblock_lock);
2518 * vfs_cancel_lock - file byte range unblock lock
2519 * @filp: The file to apply the unblock to
2520 * @fl: The lock to be unblocked
2522 * Used by lock managers to cancel blocked requests
2524 int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2526 if (filp->f_op->lock)
2527 return filp->f_op->lock(filp, F_CANCELLK, fl);
2531 EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2533 #ifdef CONFIG_PROC_FS
2534 #include <linux/proc_fs.h>
2535 #include <linux/seq_file.h>
2537 struct locks_iterator {
2542 static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2543 loff_t id, char *pfx)
2545 struct inode *inode = NULL;
2546 unsigned int fl_pid;
2549 fl_pid = pid_vnr(fl->fl_nspid);
2551 fl_pid = fl->fl_pid;
2553 if (fl->fl_file != NULL)
2554 inode = file_inode(fl->fl_file);
2556 seq_printf(f, "%lld:%s ", id, pfx);
2558 if (fl->fl_flags & FL_ACCESS)
2559 seq_puts(f, "ACCESS");
2560 else if (IS_OFDLCK(fl))
2561 seq_puts(f, "OFDLCK");
2563 seq_puts(f, "POSIX ");
2565 seq_printf(f, " %s ",
2566 (inode == NULL) ? "*NOINODE*" :
2567 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2568 } else if (IS_FLOCK(fl)) {
2569 if (fl->fl_type & LOCK_MAND) {
2570 seq_puts(f, "FLOCK MSNFS ");
2572 seq_puts(f, "FLOCK ADVISORY ");
2574 } else if (IS_LEASE(fl)) {
2575 if (fl->fl_flags & FL_DELEG)
2576 seq_puts(f, "DELEG ");
2578 seq_puts(f, "LEASE ");
2580 if (lease_breaking(fl))
2581 seq_puts(f, "BREAKING ");
2582 else if (fl->fl_file)
2583 seq_puts(f, "ACTIVE ");
2585 seq_puts(f, "BREAKER ");
2587 seq_puts(f, "UNKNOWN UNKNOWN ");
2589 if (fl->fl_type & LOCK_MAND) {
2590 seq_printf(f, "%s ",
2591 (fl->fl_type & LOCK_READ)
2592 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2593 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2595 seq_printf(f, "%s ",
2596 (lease_breaking(fl))
2597 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2598 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
2601 #ifdef WE_CAN_BREAK_LSLK_NOW
2602 seq_printf(f, "%d %s:%ld ", fl_pid,
2603 inode->i_sb->s_id, inode->i_ino);
2605 /* userspace relies on this representation of dev_t ;-( */
2606 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
2607 MAJOR(inode->i_sb->s_dev),
2608 MINOR(inode->i_sb->s_dev), inode->i_ino);
2611 seq_printf(f, "%d <none>:0 ", fl_pid);
2614 if (fl->fl_end == OFFSET_MAX)
2615 seq_printf(f, "%Ld EOF\n", fl->fl_start);
2617 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2619 seq_puts(f, "0 EOF\n");
2623 static int locks_show(struct seq_file *f, void *v)
2625 struct locks_iterator *iter = f->private;
2626 struct file_lock *fl, *bfl;
2628 fl = hlist_entry(v, struct file_lock, fl_link);
2630 lock_get_status(f, fl, iter->li_pos, "");
2632 list_for_each_entry(bfl, &fl->fl_block, fl_block)
2633 lock_get_status(f, bfl, iter->li_pos, " ->");
2638 static void *locks_start(struct seq_file *f, loff_t *pos)
2639 __acquires(&blocked_lock_lock)
2641 struct locks_iterator *iter = f->private;
2643 iter->li_pos = *pos + 1;
2644 lg_global_lock(&file_lock_lglock);
2645 spin_lock(&blocked_lock_lock);
2646 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
2649 static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2651 struct locks_iterator *iter = f->private;
2654 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
2657 static void locks_stop(struct seq_file *f, void *v)
2658 __releases(&blocked_lock_lock)
2660 spin_unlock(&blocked_lock_lock);
2661 lg_global_unlock(&file_lock_lglock);
2664 static const struct seq_operations locks_seq_operations = {
2665 .start = locks_start,
2671 static int locks_open(struct inode *inode, struct file *filp)
2673 return seq_open_private(filp, &locks_seq_operations,
2674 sizeof(struct locks_iterator));
2677 static const struct file_operations proc_locks_operations = {
2680 .llseek = seq_lseek,
2681 .release = seq_release_private,
2684 static int __init proc_locks_init(void)
2686 proc_create("locks", 0, NULL, &proc_locks_operations);
2689 module_init(proc_locks_init);
2692 static int __init filelock_init(void)
2696 flctx_cache = kmem_cache_create("file_lock_ctx",
2697 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2699 filelock_cache = kmem_cache_create("file_lock_cache",
2700 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2702 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2704 for_each_possible_cpu(i)
2705 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2710 core_initcall(filelock_init);