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 *filelock_cache __read_mostly;
207 static void locks_init_lock_heads(struct file_lock *fl)
209 INIT_HLIST_NODE(&fl->fl_link);
210 INIT_LIST_HEAD(&fl->fl_block);
211 init_waitqueue_head(&fl->fl_wait);
214 /* Allocate an empty lock structure. */
215 struct file_lock *locks_alloc_lock(void)
217 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
220 locks_init_lock_heads(fl);
224 EXPORT_SYMBOL_GPL(locks_alloc_lock);
226 void locks_release_private(struct file_lock *fl)
229 if (fl->fl_ops->fl_release_private)
230 fl->fl_ops->fl_release_private(fl);
235 if (fl->fl_lmops->lm_put_owner)
236 fl->fl_lmops->lm_put_owner(fl);
240 EXPORT_SYMBOL_GPL(locks_release_private);
242 /* Free a lock which is not in use. */
243 void locks_free_lock(struct file_lock *fl)
245 BUG_ON(waitqueue_active(&fl->fl_wait));
246 BUG_ON(!list_empty(&fl->fl_block));
247 BUG_ON(!hlist_unhashed(&fl->fl_link));
249 locks_release_private(fl);
250 kmem_cache_free(filelock_cache, fl);
252 EXPORT_SYMBOL(locks_free_lock);
255 locks_dispose_list(struct list_head *dispose)
257 struct file_lock *fl;
259 while (!list_empty(dispose)) {
260 fl = list_first_entry(dispose, struct file_lock, fl_block);
261 list_del_init(&fl->fl_block);
266 void locks_init_lock(struct file_lock *fl)
268 memset(fl, 0, sizeof(struct file_lock));
269 locks_init_lock_heads(fl);
272 EXPORT_SYMBOL(locks_init_lock);
275 * Initialize a new lock from an existing file_lock structure.
277 void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
279 new->fl_owner = fl->fl_owner;
280 new->fl_pid = fl->fl_pid;
282 new->fl_flags = fl->fl_flags;
283 new->fl_type = fl->fl_type;
284 new->fl_start = fl->fl_start;
285 new->fl_end = fl->fl_end;
286 new->fl_lmops = fl->fl_lmops;
290 if (fl->fl_lmops->lm_get_owner)
291 fl->fl_lmops->lm_get_owner(new, fl);
294 EXPORT_SYMBOL(locks_copy_conflock);
296 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
298 /* "new" must be a freshly-initialized lock */
299 WARN_ON_ONCE(new->fl_ops);
301 locks_copy_conflock(new, fl);
303 new->fl_file = fl->fl_file;
304 new->fl_ops = fl->fl_ops;
307 if (fl->fl_ops->fl_copy_lock)
308 fl->fl_ops->fl_copy_lock(new, fl);
312 EXPORT_SYMBOL(locks_copy_lock);
314 static inline int flock_translate_cmd(int cmd) {
316 return cmd & (LOCK_MAND | LOCK_RW);
328 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
329 static int flock_make_lock(struct file *filp, struct file_lock **lock,
332 struct file_lock *fl;
333 int type = flock_translate_cmd(cmd);
337 fl = locks_alloc_lock();
343 fl->fl_pid = current->tgid;
344 fl->fl_flags = FL_FLOCK;
346 fl->fl_end = OFFSET_MAX;
352 static int assign_type(struct file_lock *fl, long type)
366 static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
369 switch (l->l_whence) {
374 fl->fl_start = filp->f_pos;
377 fl->fl_start = i_size_read(file_inode(filp));
382 if (l->l_start > OFFSET_MAX - fl->fl_start)
384 fl->fl_start += l->l_start;
385 if (fl->fl_start < 0)
388 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
389 POSIX-2001 defines it. */
391 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
393 fl->fl_end = fl->fl_start + l->l_len - 1;
395 } else if (l->l_len < 0) {
396 if (fl->fl_start + l->l_len < 0)
398 fl->fl_end = fl->fl_start - 1;
399 fl->fl_start += l->l_len;
401 fl->fl_end = OFFSET_MAX;
403 fl->fl_owner = current->files;
404 fl->fl_pid = current->tgid;
406 fl->fl_flags = FL_POSIX;
410 return assign_type(fl, l->l_type);
413 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
416 static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
419 struct flock64 ll = {
421 .l_whence = l->l_whence,
422 .l_start = l->l_start,
426 return flock64_to_posix_lock(filp, fl, &ll);
429 /* default lease lock manager operations */
430 static void lease_break_callback(struct file_lock *fl)
432 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
435 static const struct lock_manager_operations lease_manager_ops = {
436 .lm_break = lease_break_callback,
437 .lm_change = lease_modify,
441 * Initialize a lease, use the default lock manager operations
443 static int lease_init(struct file *filp, long type, struct file_lock *fl)
445 if (assign_type(fl, type) != 0)
448 fl->fl_owner = current->files;
449 fl->fl_pid = current->tgid;
452 fl->fl_flags = FL_LEASE;
454 fl->fl_end = OFFSET_MAX;
456 fl->fl_lmops = &lease_manager_ops;
460 /* Allocate a file_lock initialised to this type of lease */
461 static struct file_lock *lease_alloc(struct file *filp, long type)
463 struct file_lock *fl = locks_alloc_lock();
467 return ERR_PTR(error);
469 error = lease_init(filp, type, fl);
472 return ERR_PTR(error);
477 /* Check if two locks overlap each other.
479 static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
481 return ((fl1->fl_end >= fl2->fl_start) &&
482 (fl2->fl_end >= fl1->fl_start));
486 * Check whether two locks have the same owner.
488 static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
490 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
491 return fl2->fl_lmops == fl1->fl_lmops &&
492 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
493 return fl1->fl_owner == fl2->fl_owner;
496 /* Must be called with the i_lock held! */
497 static void locks_insert_global_locks(struct file_lock *fl)
499 lg_local_lock(&file_lock_lglock);
500 fl->fl_link_cpu = smp_processor_id();
501 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
502 lg_local_unlock(&file_lock_lglock);
505 /* Must be called with the i_lock held! */
506 static void locks_delete_global_locks(struct file_lock *fl)
509 * Avoid taking lock if already unhashed. This is safe since this check
510 * is done while holding the i_lock, and new insertions into the list
511 * also require that it be held.
513 if (hlist_unhashed(&fl->fl_link))
515 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
516 hlist_del_init(&fl->fl_link);
517 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
521 posix_owner_key(struct file_lock *fl)
523 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
524 return fl->fl_lmops->lm_owner_key(fl);
525 return (unsigned long)fl->fl_owner;
528 static void locks_insert_global_blocked(struct file_lock *waiter)
530 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
533 static void locks_delete_global_blocked(struct file_lock *waiter)
535 hash_del(&waiter->fl_link);
538 /* Remove waiter from blocker's block list.
539 * When blocker ends up pointing to itself then the list is empty.
541 * Must be called with blocked_lock_lock held.
543 static void __locks_delete_block(struct file_lock *waiter)
545 locks_delete_global_blocked(waiter);
546 list_del_init(&waiter->fl_block);
547 waiter->fl_next = NULL;
550 static void locks_delete_block(struct file_lock *waiter)
552 spin_lock(&blocked_lock_lock);
553 __locks_delete_block(waiter);
554 spin_unlock(&blocked_lock_lock);
557 /* Insert waiter into blocker's block list.
558 * We use a circular list so that processes can be easily woken up in
559 * the order they blocked. The documentation doesn't require this but
560 * it seems like the reasonable thing to do.
562 * Must be called with both the i_lock and blocked_lock_lock held. The fl_block
563 * list itself is protected by the blocked_lock_lock, but by ensuring that the
564 * i_lock is also held on insertions we can avoid taking the blocked_lock_lock
565 * in some cases when we see that the fl_block list is empty.
567 static void __locks_insert_block(struct file_lock *blocker,
568 struct file_lock *waiter)
570 BUG_ON(!list_empty(&waiter->fl_block));
571 waiter->fl_next = blocker;
572 list_add_tail(&waiter->fl_block, &blocker->fl_block);
573 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
574 locks_insert_global_blocked(waiter);
577 /* Must be called with i_lock held. */
578 static void locks_insert_block(struct file_lock *blocker,
579 struct file_lock *waiter)
581 spin_lock(&blocked_lock_lock);
582 __locks_insert_block(blocker, waiter);
583 spin_unlock(&blocked_lock_lock);
587 * Wake up processes blocked waiting for blocker.
589 * Must be called with the inode->i_lock held!
591 static void locks_wake_up_blocks(struct file_lock *blocker)
594 * Avoid taking global lock if list is empty. This is safe since new
595 * blocked requests are only added to the list under the i_lock, and
596 * the i_lock is always held here. Note that removal from the fl_block
597 * list does not require the i_lock, so we must recheck list_empty()
598 * after acquiring the blocked_lock_lock.
600 if (list_empty(&blocker->fl_block))
603 spin_lock(&blocked_lock_lock);
604 while (!list_empty(&blocker->fl_block)) {
605 struct file_lock *waiter;
607 waiter = list_first_entry(&blocker->fl_block,
608 struct file_lock, fl_block);
609 __locks_delete_block(waiter);
610 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
611 waiter->fl_lmops->lm_notify(waiter);
613 wake_up(&waiter->fl_wait);
615 spin_unlock(&blocked_lock_lock);
618 /* Insert file lock fl into an inode's lock list at the position indicated
619 * by pos. At the same time add the lock to the global file lock list.
621 * Must be called with the i_lock held!
623 static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
625 fl->fl_nspid = get_pid(task_tgid(current));
627 /* insert into file's list */
631 locks_insert_global_locks(fl);
635 * locks_delete_lock - Delete a lock and then free it.
636 * @thisfl_p: pointer that points to the fl_next field of the previous
637 * inode->i_flock list entry
639 * Unlink a lock from all lists and free the namespace reference, but don't
640 * free it yet. Wake up processes that are blocked waiting for this lock and
641 * notify the FS that the lock has been cleared.
643 * Must be called with the i_lock held!
645 static void locks_unlink_lock(struct file_lock **thisfl_p)
647 struct file_lock *fl = *thisfl_p;
649 locks_delete_global_locks(fl);
651 *thisfl_p = fl->fl_next;
655 put_pid(fl->fl_nspid);
659 locks_wake_up_blocks(fl);
663 * Unlink a lock from all lists and free it.
665 * Must be called with i_lock held!
667 static void locks_delete_lock(struct file_lock **thisfl_p,
668 struct list_head *dispose)
670 struct file_lock *fl = *thisfl_p;
672 locks_unlink_lock(thisfl_p);
674 list_add(&fl->fl_block, dispose);
679 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
680 * checks for shared/exclusive status of overlapping locks.
682 static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
684 if (sys_fl->fl_type == F_WRLCK)
686 if (caller_fl->fl_type == F_WRLCK)
691 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
692 * checking before calling the locks_conflict().
694 static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
696 /* POSIX locks owned by the same process do not conflict with
699 if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl))
702 /* Check whether they overlap */
703 if (!locks_overlap(caller_fl, sys_fl))
706 return (locks_conflict(caller_fl, sys_fl));
709 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
710 * checking before calling the locks_conflict().
712 static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
714 /* FLOCK locks referring to the same filp do not conflict with
717 if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
719 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
722 return (locks_conflict(caller_fl, sys_fl));
726 posix_test_lock(struct file *filp, struct file_lock *fl)
728 struct file_lock *cfl;
729 struct inode *inode = file_inode(filp);
731 spin_lock(&inode->i_lock);
732 for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
735 if (posix_locks_conflict(fl, cfl))
739 locks_copy_conflock(fl, cfl);
741 fl->fl_pid = pid_vnr(cfl->fl_nspid);
743 fl->fl_type = F_UNLCK;
744 spin_unlock(&inode->i_lock);
747 EXPORT_SYMBOL(posix_test_lock);
750 * Deadlock detection:
752 * We attempt to detect deadlocks that are due purely to posix file
755 * We assume that a task can be waiting for at most one lock at a time.
756 * So for any acquired lock, the process holding that lock may be
757 * waiting on at most one other lock. That lock in turns may be held by
758 * someone waiting for at most one other lock. Given a requested lock
759 * caller_fl which is about to wait for a conflicting lock block_fl, we
760 * follow this chain of waiters to ensure we are not about to create a
763 * Since we do this before we ever put a process to sleep on a lock, we
764 * are ensured that there is never a cycle; that is what guarantees that
765 * the while() loop in posix_locks_deadlock() eventually completes.
767 * Note: the above assumption may not be true when handling lock
768 * requests from a broken NFS client. It may also fail in the presence
769 * of tasks (such as posix threads) sharing the same open file table.
770 * To handle those cases, we just bail out after a few iterations.
772 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
773 * Because the owner is not even nominally tied to a thread of
774 * execution, the deadlock detection below can't reasonably work well. Just
777 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
778 * locks that just checks for the case where two tasks are attempting to
779 * upgrade from read to write locks on the same inode.
782 #define MAX_DEADLK_ITERATIONS 10
784 /* Find a lock that the owner of the given block_fl is blocking on. */
785 static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
787 struct file_lock *fl;
789 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
790 if (posix_same_owner(fl, block_fl))
796 /* Must be called with the blocked_lock_lock held! */
797 static int posix_locks_deadlock(struct file_lock *caller_fl,
798 struct file_lock *block_fl)
803 * This deadlock detector can't reasonably detect deadlocks with
804 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
806 if (IS_OFDLCK(caller_fl))
809 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
810 if (i++ > MAX_DEADLK_ITERATIONS)
812 if (posix_same_owner(caller_fl, block_fl))
818 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
819 * after any leases, but before any posix locks.
821 * Note that if called with an FL_EXISTS argument, the caller may determine
822 * whether or not a lock was successfully freed by testing the return
825 static int flock_lock_file(struct file *filp, struct file_lock *request)
827 struct file_lock *new_fl = NULL;
828 struct file_lock **before;
829 struct inode * inode = file_inode(filp);
834 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
835 new_fl = locks_alloc_lock();
840 spin_lock(&inode->i_lock);
841 if (request->fl_flags & FL_ACCESS)
844 for_each_lock(inode, before) {
845 struct file_lock *fl = *before;
850 if (filp != fl->fl_file)
852 if (request->fl_type == fl->fl_type)
855 locks_delete_lock(before, &dispose);
859 if (request->fl_type == F_UNLCK) {
860 if ((request->fl_flags & FL_EXISTS) && !found)
866 * If a higher-priority process was blocked on the old file lock,
867 * give it the opportunity to lock the file.
870 spin_unlock(&inode->i_lock);
872 spin_lock(&inode->i_lock);
876 for_each_lock(inode, before) {
877 struct file_lock *fl = *before;
882 if (!flock_locks_conflict(request, fl))
885 if (!(request->fl_flags & FL_SLEEP))
887 error = FILE_LOCK_DEFERRED;
888 locks_insert_block(fl, request);
891 if (request->fl_flags & FL_ACCESS)
893 locks_copy_lock(new_fl, request);
894 locks_insert_lock(before, new_fl);
899 spin_unlock(&inode->i_lock);
901 locks_free_lock(new_fl);
902 locks_dispose_list(&dispose);
906 static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
908 struct file_lock *fl;
909 struct file_lock *new_fl = NULL;
910 struct file_lock *new_fl2 = NULL;
911 struct file_lock *left = NULL;
912 struct file_lock *right = NULL;
913 struct file_lock **before;
919 * We may need two file_lock structures for this operation,
920 * so we get them in advance to avoid races.
922 * In some cases we can be sure, that no new locks will be needed
924 if (!(request->fl_flags & FL_ACCESS) &&
925 (request->fl_type != F_UNLCK ||
926 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
927 new_fl = locks_alloc_lock();
928 new_fl2 = locks_alloc_lock();
931 spin_lock(&inode->i_lock);
933 * New lock request. Walk all POSIX locks and look for conflicts. If
934 * there are any, either return error or put the request on the
935 * blocker's list of waiters and the global blocked_hash.
937 if (request->fl_type != F_UNLCK) {
938 for_each_lock(inode, before) {
942 if (!posix_locks_conflict(request, fl))
945 locks_copy_conflock(conflock, fl);
947 if (!(request->fl_flags & FL_SLEEP))
950 * Deadlock detection and insertion into the blocked
951 * locks list must be done while holding the same lock!
954 spin_lock(&blocked_lock_lock);
955 if (likely(!posix_locks_deadlock(request, fl))) {
956 error = FILE_LOCK_DEFERRED;
957 __locks_insert_block(fl, request);
959 spin_unlock(&blocked_lock_lock);
964 /* If we're just looking for a conflict, we're done. */
966 if (request->fl_flags & FL_ACCESS)
970 * Find the first old lock with the same owner as the new lock.
973 before = &inode->i_flock;
975 /* First skip locks owned by other processes. */
976 while ((fl = *before) && (!IS_POSIX(fl) ||
977 !posix_same_owner(request, fl))) {
978 before = &fl->fl_next;
981 /* Process locks with this owner. */
982 while ((fl = *before) && posix_same_owner(request, fl)) {
983 /* Detect adjacent or overlapping regions (if same lock type)
985 if (request->fl_type == fl->fl_type) {
986 /* In all comparisons of start vs end, use
987 * "start - 1" rather than "end + 1". If end
988 * is OFFSET_MAX, end + 1 will become negative.
990 if (fl->fl_end < request->fl_start - 1)
992 /* If the next lock in the list has entirely bigger
993 * addresses than the new one, insert the lock here.
995 if (fl->fl_start - 1 > request->fl_end)
998 /* If we come here, the new and old lock are of the
999 * same type and adjacent or overlapping. Make one
1000 * lock yielding from the lower start address of both
1001 * locks to the higher end address.
1003 if (fl->fl_start > request->fl_start)
1004 fl->fl_start = request->fl_start;
1006 request->fl_start = fl->fl_start;
1007 if (fl->fl_end < request->fl_end)
1008 fl->fl_end = request->fl_end;
1010 request->fl_end = fl->fl_end;
1012 locks_delete_lock(before, &dispose);
1019 /* Processing for different lock types is a bit
1022 if (fl->fl_end < request->fl_start)
1024 if (fl->fl_start > request->fl_end)
1026 if (request->fl_type == F_UNLCK)
1028 if (fl->fl_start < request->fl_start)
1030 /* If the next lock in the list has a higher end
1031 * address than the new one, insert the new one here.
1033 if (fl->fl_end > request->fl_end) {
1037 if (fl->fl_start >= request->fl_start) {
1038 /* The new lock completely replaces an old
1039 * one (This may happen several times).
1042 locks_delete_lock(before, &dispose);
1046 * Replace the old lock with new_fl, and
1047 * remove the old one. It's safe to do the
1048 * insert here since we know that we won't be
1049 * using new_fl later, and that the lock is
1050 * just replacing an existing lock.
1055 locks_copy_lock(new_fl, request);
1058 locks_delete_lock(before, &dispose);
1059 locks_insert_lock(before, request);
1063 /* Go on to next lock.
1066 before = &fl->fl_next;
1070 * The above code only modifies existing locks in case of merging or
1071 * replacing. If new lock(s) need to be inserted all modifications are
1072 * done below this, so it's safe yet to bail out.
1074 error = -ENOLCK; /* "no luck" */
1075 if (right && left == right && !new_fl2)
1080 if (request->fl_type == F_UNLCK) {
1081 if (request->fl_flags & FL_EXISTS)
1090 locks_copy_lock(new_fl, request);
1091 locks_insert_lock(before, new_fl);
1095 if (left == right) {
1096 /* The new lock breaks the old one in two pieces,
1097 * so we have to use the second new lock.
1101 locks_copy_lock(left, right);
1102 locks_insert_lock(before, left);
1104 right->fl_start = request->fl_end + 1;
1105 locks_wake_up_blocks(right);
1108 left->fl_end = request->fl_start - 1;
1109 locks_wake_up_blocks(left);
1112 spin_unlock(&inode->i_lock);
1114 * Free any unused locks.
1117 locks_free_lock(new_fl);
1119 locks_free_lock(new_fl2);
1120 locks_dispose_list(&dispose);
1125 * posix_lock_file - Apply a POSIX-style lock to a file
1126 * @filp: The file to apply the lock to
1127 * @fl: The lock to be applied
1128 * @conflock: Place to return a copy of the conflicting lock, if found.
1130 * Add a POSIX style lock to a file.
1131 * We merge adjacent & overlapping locks whenever possible.
1132 * POSIX locks are sorted by owner task, then by starting address
1134 * Note that if called with an FL_EXISTS argument, the caller may determine
1135 * whether or not a lock was successfully freed by testing the return
1136 * value for -ENOENT.
1138 int posix_lock_file(struct file *filp, struct file_lock *fl,
1139 struct file_lock *conflock)
1141 return __posix_lock_file(file_inode(filp), fl, conflock);
1143 EXPORT_SYMBOL(posix_lock_file);
1146 * posix_lock_file_wait - Apply a POSIX-style lock to a file
1147 * @filp: The file to apply the lock to
1148 * @fl: The lock to be applied
1150 * Add a POSIX style lock to a file.
1151 * We merge adjacent & overlapping locks whenever possible.
1152 * POSIX locks are sorted by owner task, then by starting address
1154 int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1159 error = posix_lock_file(filp, fl, NULL);
1160 if (error != FILE_LOCK_DEFERRED)
1162 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1166 locks_delete_block(fl);
1171 EXPORT_SYMBOL(posix_lock_file_wait);
1174 * locks_mandatory_locked - Check for an active lock
1175 * @file: the file to check
1177 * Searches the inode's list of locks to find any POSIX locks which conflict.
1178 * This function is called from locks_verify_locked() only.
1180 int locks_mandatory_locked(struct file *file)
1182 struct inode *inode = file_inode(file);
1183 struct file_lock *fl;
1186 * Search the lock list for this inode for any POSIX locks.
1188 spin_lock(&inode->i_lock);
1189 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
1192 if (fl->fl_owner != current->files &&
1193 fl->fl_owner != file)
1196 spin_unlock(&inode->i_lock);
1197 return fl ? -EAGAIN : 0;
1201 * locks_mandatory_area - Check for a conflicting lock
1202 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1204 * @inode: the file to check
1205 * @filp: how the file was opened (if it was)
1206 * @offset: start of area to check
1207 * @count: length of area to check
1209 * Searches the inode's list of locks to find any POSIX locks which conflict.
1210 * This function is called from rw_verify_area() and
1211 * locks_verify_truncate().
1213 int locks_mandatory_area(int read_write, struct inode *inode,
1214 struct file *filp, loff_t offset,
1217 struct file_lock fl;
1221 locks_init_lock(&fl);
1222 fl.fl_pid = current->tgid;
1224 fl.fl_flags = FL_POSIX | FL_ACCESS;
1225 if (filp && !(filp->f_flags & O_NONBLOCK))
1227 fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1228 fl.fl_start = offset;
1229 fl.fl_end = offset + count - 1;
1234 fl.fl_flags &= ~FL_SLEEP;
1235 error = __posix_lock_file(inode, &fl, NULL);
1241 fl.fl_flags |= FL_SLEEP;
1242 fl.fl_owner = current->files;
1243 error = __posix_lock_file(inode, &fl, NULL);
1244 if (error != FILE_LOCK_DEFERRED)
1246 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1249 * If we've been sleeping someone might have
1250 * changed the permissions behind our back.
1252 if (__mandatory_lock(inode))
1256 locks_delete_block(&fl);
1263 EXPORT_SYMBOL(locks_mandatory_area);
1265 static void lease_clear_pending(struct file_lock *fl, int arg)
1269 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1272 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1276 /* We already had a lease on this file; just change its type */
1277 int lease_modify(struct file_lock **before, int arg)
1279 struct file_lock *fl = *before;
1280 int error = assign_type(fl, arg);
1284 lease_clear_pending(fl, arg);
1285 locks_wake_up_blocks(fl);
1286 if (arg == F_UNLCK) {
1287 struct file *filp = fl->fl_file;
1290 filp->f_owner.signum = 0;
1291 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1292 if (fl->fl_fasync != NULL) {
1293 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1294 fl->fl_fasync = NULL;
1296 locks_delete_lock(before, NULL);
1301 EXPORT_SYMBOL(lease_modify);
1303 static bool past_time(unsigned long then)
1306 /* 0 is a special value meaning "this never expires": */
1308 return time_after(jiffies, then);
1311 static void time_out_leases(struct inode *inode)
1313 struct file_lock **before;
1314 struct file_lock *fl;
1316 before = &inode->i_flock;
1317 while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {
1318 trace_time_out_leases(inode, fl);
1319 if (past_time(fl->fl_downgrade_time))
1320 lease_modify(before, F_RDLCK);
1321 if (past_time(fl->fl_break_time))
1322 lease_modify(before, F_UNLCK);
1323 if (fl == *before) /* lease_modify may have freed fl */
1324 before = &fl->fl_next;
1328 static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1330 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1332 return locks_conflict(breaker, lease);
1336 * __break_lease - revoke all outstanding leases on file
1337 * @inode: the inode of the file to return
1338 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1340 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1343 * break_lease (inlined for speed) has checked there already is at least
1344 * some kind of lock (maybe a lease) on this file. Leases are broken on
1345 * a call to open() or truncate(). This function can sleep unless you
1346 * specified %O_NONBLOCK to your open().
1348 int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1351 struct file_lock *new_fl, *flock;
1352 struct file_lock *fl;
1353 unsigned long break_time;
1354 int i_have_this_lease = 0;
1355 bool lease_conflict = false;
1356 int want_write = (mode & O_ACCMODE) != O_RDONLY;
1358 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1360 return PTR_ERR(new_fl);
1361 new_fl->fl_flags = type;
1363 spin_lock(&inode->i_lock);
1365 time_out_leases(inode);
1367 flock = inode->i_flock;
1368 if ((flock == NULL) || !IS_LEASE(flock))
1371 for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
1372 if (leases_conflict(fl, new_fl)) {
1373 lease_conflict = true;
1374 if (fl->fl_owner == current->files)
1375 i_have_this_lease = 1;
1378 if (!lease_conflict)
1382 if (lease_break_time > 0) {
1383 break_time = jiffies + lease_break_time * HZ;
1384 if (break_time == 0)
1385 break_time++; /* so that 0 means no break time */
1388 for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
1389 if (!leases_conflict(fl, new_fl))
1392 if (fl->fl_flags & FL_UNLOCK_PENDING)
1394 fl->fl_flags |= FL_UNLOCK_PENDING;
1395 fl->fl_break_time = break_time;
1397 if (lease_breaking(flock))
1399 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1400 fl->fl_downgrade_time = break_time;
1402 fl->fl_lmops->lm_break(fl);
1405 if (i_have_this_lease || (mode & O_NONBLOCK)) {
1406 trace_break_lease_noblock(inode, new_fl);
1407 error = -EWOULDBLOCK;
1412 break_time = flock->fl_break_time;
1413 if (break_time != 0)
1414 break_time -= jiffies;
1415 if (break_time == 0)
1417 locks_insert_block(flock, new_fl);
1418 trace_break_lease_block(inode, new_fl);
1419 spin_unlock(&inode->i_lock);
1420 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1421 !new_fl->fl_next, break_time);
1422 spin_lock(&inode->i_lock);
1423 trace_break_lease_unblock(inode, new_fl);
1424 locks_delete_block(new_fl);
1427 time_out_leases(inode);
1429 * Wait for the next conflicting lease that has not been
1432 for (flock = inode->i_flock; flock && IS_LEASE(flock);
1433 flock = flock->fl_next) {
1434 if (leases_conflict(new_fl, flock))
1441 spin_unlock(&inode->i_lock);
1442 locks_free_lock(new_fl);
1446 EXPORT_SYMBOL(__break_lease);
1449 * lease_get_mtime - get the last modified time of an inode
1451 * @time: pointer to a timespec which will contain the last modified time
1453 * This is to force NFS clients to flush their caches for files with
1454 * exclusive leases. The justification is that if someone has an
1455 * exclusive lease, then they could be modifying it.
1457 void lease_get_mtime(struct inode *inode, struct timespec *time)
1459 struct file_lock *flock = inode->i_flock;
1460 if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK))
1461 *time = current_fs_time(inode->i_sb);
1463 *time = inode->i_mtime;
1466 EXPORT_SYMBOL(lease_get_mtime);
1469 * fcntl_getlease - Enquire what lease is currently active
1472 * The value returned by this function will be one of
1473 * (if no lease break is pending):
1475 * %F_RDLCK to indicate a shared lease is held.
1477 * %F_WRLCK to indicate an exclusive lease is held.
1479 * %F_UNLCK to indicate no lease is held.
1481 * (if a lease break is pending):
1483 * %F_RDLCK to indicate an exclusive lease needs to be
1484 * changed to a shared lease (or removed).
1486 * %F_UNLCK to indicate the lease needs to be removed.
1488 * XXX: sfr & willy disagree over whether F_INPROGRESS
1489 * should be returned to userspace.
1491 int fcntl_getlease(struct file *filp)
1493 struct file_lock *fl;
1494 struct inode *inode = file_inode(filp);
1497 spin_lock(&inode->i_lock);
1498 time_out_leases(file_inode(filp));
1499 for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);
1501 if (fl->fl_file == filp) {
1502 type = target_leasetype(fl);
1506 spin_unlock(&inode->i_lock);
1511 * check_conflicting_open - see if the given dentry points to a file that has
1512 * an existing open that would conflict with the
1514 * @dentry: dentry to check
1515 * @arg: type of lease that we're trying to acquire
1517 * Check to see if there's an existing open fd on this file that would
1518 * conflict with the lease we're trying to set.
1521 check_conflicting_open(const struct dentry *dentry, const long arg)
1524 struct inode *inode = dentry->d_inode;
1526 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1529 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1530 (atomic_read(&inode->i_count) > 1)))
1536 static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp)
1538 struct file_lock *fl, **before, **my_before = NULL, *lease;
1539 struct dentry *dentry = filp->f_path.dentry;
1540 struct inode *inode = dentry->d_inode;
1541 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1545 trace_generic_add_lease(inode, lease);
1548 * In the delegation case we need mutual exclusion with
1549 * a number of operations that take the i_mutex. We trylock
1550 * because delegations are an optional optimization, and if
1551 * there's some chance of a conflict--we'd rather not
1552 * bother, maybe that's a sign this just isn't a good file to
1553 * hand out a delegation on.
1555 if (is_deleg && !mutex_trylock(&inode->i_mutex))
1558 if (is_deleg && arg == F_WRLCK) {
1559 /* Write delegations are not currently supported: */
1560 mutex_unlock(&inode->i_mutex);
1565 error = check_conflicting_open(dentry, arg);
1570 * At this point, we know that if there is an exclusive
1571 * lease on this file, then we hold it on this filp
1572 * (otherwise our open of this file would have blocked).
1573 * And if we are trying to acquire an exclusive lease,
1574 * then the file is not open by anyone (including us)
1575 * except for this filp.
1578 for (before = &inode->i_flock;
1579 ((fl = *before) != NULL) && IS_LEASE(fl);
1580 before = &fl->fl_next) {
1581 if (fl->fl_file == filp) {
1586 * No exclusive leases if someone else has a lease on
1592 * Modifying our existing lease is OK, but no getting a
1593 * new lease if someone else is opening for write:
1595 if (fl->fl_flags & FL_UNLOCK_PENDING)
1599 if (my_before != NULL) {
1600 error = lease->fl_lmops->lm_change(my_before, arg);
1610 locks_insert_lock(before, lease);
1612 * The check in break_lease() is lockless. It's possible for another
1613 * open to race in after we did the earlier check for a conflicting
1614 * open but before the lease was inserted. Check again for a
1615 * conflicting open and cancel the lease if there is one.
1617 * We also add a barrier here to ensure that the insertion of the lock
1618 * precedes these checks.
1621 error = check_conflicting_open(dentry, arg);
1623 locks_unlink_lock(before);
1626 mutex_unlock(&inode->i_mutex);
1630 static int generic_delete_lease(struct file *filp, struct file_lock **flp)
1632 struct file_lock *fl, **before;
1633 struct dentry *dentry = filp->f_path.dentry;
1634 struct inode *inode = dentry->d_inode;
1636 trace_generic_delete_lease(inode, *flp);
1638 for (before = &inode->i_flock;
1639 ((fl = *before) != NULL) && IS_LEASE(fl);
1640 before = &fl->fl_next) {
1641 if (fl->fl_file != filp)
1643 return (*flp)->fl_lmops->lm_change(before, F_UNLCK);
1649 * generic_setlease - sets a lease on an open file
1650 * @filp: file pointer
1651 * @arg: type of lease to obtain
1652 * @flp: input - file_lock to use, output - file_lock inserted
1654 * The (input) flp->fl_lmops->lm_break function is required
1657 * Called with inode->i_lock held.
1659 int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
1661 struct dentry *dentry = filp->f_path.dentry;
1662 struct inode *inode = dentry->d_inode;
1665 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1667 if (!S_ISREG(inode->i_mode))
1669 error = security_file_lock(filp, arg);
1673 time_out_leases(inode);
1675 BUG_ON(!(*flp)->fl_lmops->lm_break);
1679 return generic_delete_lease(filp, flp);
1682 return generic_add_lease(filp, arg, flp);
1687 EXPORT_SYMBOL(generic_setlease);
1689 static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
1691 if (filp->f_op->setlease)
1692 return filp->f_op->setlease(filp, arg, lease);
1694 return generic_setlease(filp, arg, lease);
1698 * vfs_setlease - sets a lease on an open file
1699 * @filp: file pointer
1700 * @arg: type of lease to obtain
1701 * @lease: file_lock to use
1703 * Call this to establish a lease on the file.
1704 * The (*lease)->fl_lmops->lm_break operation must be set; if not,
1705 * break_lease will oops!
1707 * This will call the filesystem's setlease file method, if
1708 * defined. Note that there is no getlease method; instead, the
1709 * filesystem setlease method should call back to setlease() to
1710 * add a lease to the inode's lease list, where fcntl_getlease() can
1711 * find it. Since fcntl_getlease() only reports whether the current
1712 * task holds a lease, a cluster filesystem need only do this for
1713 * leases held by processes on this node.
1715 * There is also no break_lease method; filesystems that
1716 * handle their own leases should break leases themselves from the
1717 * filesystem's open, create, and (on truncate) setattr methods.
1719 * Warning: the only current setlease methods exist only to disable
1720 * leases in certain cases. More vfs changes may be required to
1721 * allow a full filesystem lease implementation.
1724 int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
1726 struct inode *inode = file_inode(filp);
1729 spin_lock(&inode->i_lock);
1730 error = __vfs_setlease(filp, arg, lease);
1731 spin_unlock(&inode->i_lock);
1735 EXPORT_SYMBOL_GPL(vfs_setlease);
1737 static int do_fcntl_delete_lease(struct file *filp)
1739 struct file_lock fl, *flp = &fl;
1741 lease_init(filp, F_UNLCK, flp);
1743 return vfs_setlease(filp, F_UNLCK, &flp);
1746 static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
1748 struct file_lock *fl, *ret;
1749 struct inode *inode = file_inode(filp);
1750 struct fasync_struct *new;
1753 fl = lease_alloc(filp, arg);
1757 new = fasync_alloc();
1759 locks_free_lock(fl);
1763 spin_lock(&inode->i_lock);
1764 error = __vfs_setlease(filp, arg, &ret);
1771 * fasync_insert_entry() returns the old entry if any.
1772 * If there was no old entry, then it used 'new' and
1773 * inserted it into the fasync list. Clear new so that
1774 * we don't release it here.
1776 if (!fasync_insert_entry(fd, filp, &ret->fl_fasync, new))
1779 error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
1781 spin_unlock(&inode->i_lock);
1783 locks_free_lock(fl);
1790 * fcntl_setlease - sets a lease on an open file
1791 * @fd: open file descriptor
1792 * @filp: file pointer
1793 * @arg: type of lease to obtain
1795 * Call this fcntl to establish a lease on the file.
1796 * Note that you also need to call %F_SETSIG to
1797 * receive a signal when the lease is broken.
1799 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1802 return do_fcntl_delete_lease(filp);
1803 return do_fcntl_add_lease(fd, filp, arg);
1807 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1808 * @filp: The file to apply the lock to
1809 * @fl: The lock to be applied
1811 * Add a FLOCK style lock to a file.
1813 int flock_lock_file_wait(struct file *filp, struct file_lock *fl)
1818 error = flock_lock_file(filp, fl);
1819 if (error != FILE_LOCK_DEFERRED)
1821 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1825 locks_delete_block(fl);
1831 EXPORT_SYMBOL(flock_lock_file_wait);
1834 * sys_flock: - flock() system call.
1835 * @fd: the file descriptor to lock.
1836 * @cmd: the type of lock to apply.
1838 * Apply a %FL_FLOCK style lock to an open file descriptor.
1839 * The @cmd can be one of
1841 * %LOCK_SH -- a shared lock.
1843 * %LOCK_EX -- an exclusive lock.
1845 * %LOCK_UN -- remove an existing lock.
1847 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1849 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1850 * processes read and write access respectively.
1852 SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
1854 struct fd f = fdget(fd);
1855 struct file_lock *lock;
1856 int can_sleep, unlock;
1863 can_sleep = !(cmd & LOCK_NB);
1865 unlock = (cmd == LOCK_UN);
1867 if (!unlock && !(cmd & LOCK_MAND) &&
1868 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
1871 error = flock_make_lock(f.file, &lock, cmd);
1875 lock->fl_flags |= FL_SLEEP;
1877 error = security_file_lock(f.file, lock->fl_type);
1881 if (f.file->f_op->flock)
1882 error = f.file->f_op->flock(f.file,
1883 (can_sleep) ? F_SETLKW : F_SETLK,
1886 error = flock_lock_file_wait(f.file, lock);
1889 locks_free_lock(lock);
1898 * vfs_test_lock - test file byte range lock
1899 * @filp: The file to test lock for
1900 * @fl: The lock to test; also used to hold result
1902 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1903 * setting conf->fl_type to something other than F_UNLCK.
1905 int vfs_test_lock(struct file *filp, struct file_lock *fl)
1907 if (filp->f_op->lock)
1908 return filp->f_op->lock(filp, F_GETLK, fl);
1909 posix_test_lock(filp, fl);
1912 EXPORT_SYMBOL_GPL(vfs_test_lock);
1914 static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
1916 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
1917 #if BITS_PER_LONG == 32
1919 * Make sure we can represent the posix lock via
1920 * legacy 32bit flock.
1922 if (fl->fl_start > OFFT_OFFSET_MAX)
1924 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
1927 flock->l_start = fl->fl_start;
1928 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1929 fl->fl_end - fl->fl_start + 1;
1930 flock->l_whence = 0;
1931 flock->l_type = fl->fl_type;
1935 #if BITS_PER_LONG == 32
1936 static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
1938 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
1939 flock->l_start = fl->fl_start;
1940 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1941 fl->fl_end - fl->fl_start + 1;
1942 flock->l_whence = 0;
1943 flock->l_type = fl->fl_type;
1947 /* Report the first existing lock that would conflict with l.
1948 * This implements the F_GETLK command of fcntl().
1950 int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
1952 struct file_lock file_lock;
1957 if (copy_from_user(&flock, l, sizeof(flock)))
1960 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
1963 error = flock_to_posix_lock(filp, &file_lock, &flock);
1967 if (cmd == F_OFD_GETLK) {
1969 if (flock.l_pid != 0)
1973 file_lock.fl_flags |= FL_OFDLCK;
1974 file_lock.fl_owner = filp;
1977 error = vfs_test_lock(filp, &file_lock);
1981 flock.l_type = file_lock.fl_type;
1982 if (file_lock.fl_type != F_UNLCK) {
1983 error = posix_lock_to_flock(&flock, &file_lock);
1988 if (!copy_to_user(l, &flock, sizeof(flock)))
1991 locks_release_private(&file_lock);
1997 * vfs_lock_file - file byte range lock
1998 * @filp: The file to apply the lock to
1999 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2000 * @fl: The lock to be applied
2001 * @conf: Place to return a copy of the conflicting lock, if found.
2003 * A caller that doesn't care about the conflicting lock may pass NULL
2004 * as the final argument.
2006 * If the filesystem defines a private ->lock() method, then @conf will
2007 * be left unchanged; so a caller that cares should initialize it to
2008 * some acceptable default.
2010 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2011 * locks, the ->lock() interface may return asynchronously, before the lock has
2012 * been granted or denied by the underlying filesystem, if (and only if)
2013 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2014 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2015 * the request is for a blocking lock. When ->lock() does return asynchronously,
2016 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2017 * request completes.
2018 * If the request is for non-blocking lock the file system should return
2019 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2020 * with the result. If the request timed out the callback routine will return a
2021 * nonzero return code and the file system should release the lock. The file
2022 * system is also responsible to keep a corresponding posix lock when it
2023 * grants a lock so the VFS can find out which locks are locally held and do
2024 * the correct lock cleanup when required.
2025 * The underlying filesystem must not drop the kernel lock or call
2026 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2029 int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2031 if (filp->f_op->lock)
2032 return filp->f_op->lock(filp, cmd, fl);
2034 return posix_lock_file(filp, fl, conf);
2036 EXPORT_SYMBOL_GPL(vfs_lock_file);
2038 static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2039 struct file_lock *fl)
2043 error = security_file_lock(filp, fl->fl_type);
2048 error = vfs_lock_file(filp, cmd, fl, NULL);
2049 if (error != FILE_LOCK_DEFERRED)
2051 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2055 locks_delete_block(fl);
2062 /* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
2064 check_fmode_for_setlk(struct file_lock *fl)
2066 switch (fl->fl_type) {
2068 if (!(fl->fl_file->f_mode & FMODE_READ))
2072 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2078 /* Apply the lock described by l to an open file descriptor.
2079 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2081 int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2082 struct flock __user *l)
2084 struct file_lock *file_lock = locks_alloc_lock();
2086 struct inode *inode;
2090 if (file_lock == NULL)
2094 * This might block, so we do it before checking the inode.
2097 if (copy_from_user(&flock, l, sizeof(flock)))
2100 inode = file_inode(filp);
2102 /* Don't allow mandatory locks on files that may be memory mapped
2105 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2111 error = flock_to_posix_lock(filp, file_lock, &flock);
2115 error = check_fmode_for_setlk(file_lock);
2120 * If the cmd is requesting file-private locks, then set the
2121 * FL_OFDLCK flag and override the owner.
2126 if (flock.l_pid != 0)
2130 file_lock->fl_flags |= FL_OFDLCK;
2131 file_lock->fl_owner = filp;
2135 if (flock.l_pid != 0)
2139 file_lock->fl_flags |= FL_OFDLCK;
2140 file_lock->fl_owner = filp;
2143 file_lock->fl_flags |= FL_SLEEP;
2146 error = do_lock_file_wait(filp, cmd, file_lock);
2149 * Attempt to detect a close/fcntl race and recover by
2150 * releasing the lock that was just acquired.
2153 * we need that spin_lock here - it prevents reordering between
2154 * update of inode->i_flock and check for it done in close().
2155 * rcu_read_lock() wouldn't do.
2157 spin_lock(¤t->files->file_lock);
2159 spin_unlock(¤t->files->file_lock);
2160 if (!error && f != filp && flock.l_type != F_UNLCK) {
2161 flock.l_type = F_UNLCK;
2166 locks_free_lock(file_lock);
2170 #if BITS_PER_LONG == 32
2171 /* Report the first existing lock that would conflict with l.
2172 * This implements the F_GETLK command of fcntl().
2174 int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
2176 struct file_lock file_lock;
2177 struct flock64 flock;
2181 if (copy_from_user(&flock, l, sizeof(flock)))
2184 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2187 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2191 if (cmd == F_OFD_GETLK) {
2193 if (flock.l_pid != 0)
2197 file_lock.fl_flags |= FL_OFDLCK;
2198 file_lock.fl_owner = filp;
2201 error = vfs_test_lock(filp, &file_lock);
2205 flock.l_type = file_lock.fl_type;
2206 if (file_lock.fl_type != F_UNLCK)
2207 posix_lock_to_flock64(&flock, &file_lock);
2210 if (!copy_to_user(l, &flock, sizeof(flock)))
2213 locks_release_private(&file_lock);
2218 /* Apply the lock described by l to an open file descriptor.
2219 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2221 int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2222 struct flock64 __user *l)
2224 struct file_lock *file_lock = locks_alloc_lock();
2225 struct flock64 flock;
2226 struct inode *inode;
2230 if (file_lock == NULL)
2234 * This might block, so we do it before checking the inode.
2237 if (copy_from_user(&flock, l, sizeof(flock)))
2240 inode = file_inode(filp);
2242 /* Don't allow mandatory locks on files that may be memory mapped
2245 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2251 error = flock64_to_posix_lock(filp, file_lock, &flock);
2255 error = check_fmode_for_setlk(file_lock);
2260 * If the cmd is requesting file-private locks, then set the
2261 * FL_OFDLCK flag and override the owner.
2266 if (flock.l_pid != 0)
2270 file_lock->fl_flags |= FL_OFDLCK;
2271 file_lock->fl_owner = filp;
2275 if (flock.l_pid != 0)
2279 file_lock->fl_flags |= FL_OFDLCK;
2280 file_lock->fl_owner = filp;
2283 file_lock->fl_flags |= FL_SLEEP;
2286 error = do_lock_file_wait(filp, cmd, file_lock);
2289 * Attempt to detect a close/fcntl race and recover by
2290 * releasing the lock that was just acquired.
2292 spin_lock(¤t->files->file_lock);
2294 spin_unlock(¤t->files->file_lock);
2295 if (!error && f != filp && flock.l_type != F_UNLCK) {
2296 flock.l_type = F_UNLCK;
2301 locks_free_lock(file_lock);
2304 #endif /* BITS_PER_LONG == 32 */
2307 * This function is called when the file is being removed
2308 * from the task's fd array. POSIX locks belonging to this task
2309 * are deleted at this time.
2311 void locks_remove_posix(struct file *filp, fl_owner_t owner)
2313 struct file_lock lock;
2316 * If there are no locks held on this file, we don't need to call
2317 * posix_lock_file(). Another process could be setting a lock on this
2318 * file at the same time, but we wouldn't remove that lock anyway.
2320 if (!file_inode(filp)->i_flock)
2323 lock.fl_type = F_UNLCK;
2324 lock.fl_flags = FL_POSIX | FL_CLOSE;
2326 lock.fl_end = OFFSET_MAX;
2327 lock.fl_owner = owner;
2328 lock.fl_pid = current->tgid;
2329 lock.fl_file = filp;
2331 lock.fl_lmops = NULL;
2333 vfs_lock_file(filp, F_SETLK, &lock, NULL);
2335 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2336 lock.fl_ops->fl_release_private(&lock);
2339 EXPORT_SYMBOL(locks_remove_posix);
2342 * This function is called on the last close of an open file.
2344 void locks_remove_file(struct file *filp)
2346 struct inode * inode = file_inode(filp);
2347 struct file_lock *fl;
2348 struct file_lock **before;
2351 if (!inode->i_flock)
2354 locks_remove_posix(filp, filp);
2356 if (filp->f_op->flock) {
2357 struct file_lock fl = {
2359 .fl_pid = current->tgid,
2361 .fl_flags = FL_FLOCK,
2363 .fl_end = OFFSET_MAX,
2365 filp->f_op->flock(filp, F_SETLKW, &fl);
2366 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2367 fl.fl_ops->fl_release_private(&fl);
2370 spin_lock(&inode->i_lock);
2371 before = &inode->i_flock;
2373 while ((fl = *before) != NULL) {
2374 if (fl->fl_file == filp) {
2376 lease_modify(before, F_UNLCK);
2381 * There's a leftover lock on the list of a type that
2382 * we didn't expect to see. Most likely a classic
2383 * POSIX lock that ended up not getting released
2384 * properly, or that raced onto the list somehow. Log
2385 * some info about it and then just remove it from
2389 "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n",
2390 MAJOR(inode->i_sb->s_dev),
2391 MINOR(inode->i_sb->s_dev), inode->i_ino,
2392 fl->fl_type, fl->fl_flags,
2393 fl->fl_start, fl->fl_end);
2395 locks_delete_lock(before, &dispose);
2398 before = &fl->fl_next;
2400 spin_unlock(&inode->i_lock);
2401 locks_dispose_list(&dispose);
2405 * posix_unblock_lock - stop waiting for a file lock
2406 * @waiter: the lock which was waiting
2408 * lockd needs to block waiting for locks.
2411 posix_unblock_lock(struct file_lock *waiter)
2415 spin_lock(&blocked_lock_lock);
2416 if (waiter->fl_next)
2417 __locks_delete_block(waiter);
2420 spin_unlock(&blocked_lock_lock);
2423 EXPORT_SYMBOL(posix_unblock_lock);
2426 * vfs_cancel_lock - file byte range unblock lock
2427 * @filp: The file to apply the unblock to
2428 * @fl: The lock to be unblocked
2430 * Used by lock managers to cancel blocked requests
2432 int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2434 if (filp->f_op->lock)
2435 return filp->f_op->lock(filp, F_CANCELLK, fl);
2439 EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2441 #ifdef CONFIG_PROC_FS
2442 #include <linux/proc_fs.h>
2443 #include <linux/seq_file.h>
2445 struct locks_iterator {
2450 static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2451 loff_t id, char *pfx)
2453 struct inode *inode = NULL;
2454 unsigned int fl_pid;
2457 fl_pid = pid_vnr(fl->fl_nspid);
2459 fl_pid = fl->fl_pid;
2461 if (fl->fl_file != NULL)
2462 inode = file_inode(fl->fl_file);
2464 seq_printf(f, "%lld:%s ", id, pfx);
2466 if (fl->fl_flags & FL_ACCESS)
2467 seq_puts(f, "ACCESS");
2468 else if (IS_OFDLCK(fl))
2469 seq_puts(f, "OFDLCK");
2471 seq_puts(f, "POSIX ");
2473 seq_printf(f, " %s ",
2474 (inode == NULL) ? "*NOINODE*" :
2475 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2476 } else if (IS_FLOCK(fl)) {
2477 if (fl->fl_type & LOCK_MAND) {
2478 seq_puts(f, "FLOCK MSNFS ");
2480 seq_puts(f, "FLOCK ADVISORY ");
2482 } else if (IS_LEASE(fl)) {
2483 if (fl->fl_flags & FL_DELEG)
2484 seq_puts(f, "DELEG ");
2486 seq_puts(f, "LEASE ");
2488 if (lease_breaking(fl))
2489 seq_puts(f, "BREAKING ");
2490 else if (fl->fl_file)
2491 seq_puts(f, "ACTIVE ");
2493 seq_puts(f, "BREAKER ");
2495 seq_puts(f, "UNKNOWN UNKNOWN ");
2497 if (fl->fl_type & LOCK_MAND) {
2498 seq_printf(f, "%s ",
2499 (fl->fl_type & LOCK_READ)
2500 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2501 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2503 seq_printf(f, "%s ",
2504 (lease_breaking(fl))
2505 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2506 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
2509 #ifdef WE_CAN_BREAK_LSLK_NOW
2510 seq_printf(f, "%d %s:%ld ", fl_pid,
2511 inode->i_sb->s_id, inode->i_ino);
2513 /* userspace relies on this representation of dev_t ;-( */
2514 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
2515 MAJOR(inode->i_sb->s_dev),
2516 MINOR(inode->i_sb->s_dev), inode->i_ino);
2519 seq_printf(f, "%d <none>:0 ", fl_pid);
2522 if (fl->fl_end == OFFSET_MAX)
2523 seq_printf(f, "%Ld EOF\n", fl->fl_start);
2525 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2527 seq_puts(f, "0 EOF\n");
2531 static int locks_show(struct seq_file *f, void *v)
2533 struct locks_iterator *iter = f->private;
2534 struct file_lock *fl, *bfl;
2536 fl = hlist_entry(v, struct file_lock, fl_link);
2538 lock_get_status(f, fl, iter->li_pos, "");
2540 list_for_each_entry(bfl, &fl->fl_block, fl_block)
2541 lock_get_status(f, bfl, iter->li_pos, " ->");
2546 static void *locks_start(struct seq_file *f, loff_t *pos)
2547 __acquires(&blocked_lock_lock)
2549 struct locks_iterator *iter = f->private;
2551 iter->li_pos = *pos + 1;
2552 lg_global_lock(&file_lock_lglock);
2553 spin_lock(&blocked_lock_lock);
2554 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
2557 static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2559 struct locks_iterator *iter = f->private;
2562 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
2565 static void locks_stop(struct seq_file *f, void *v)
2566 __releases(&blocked_lock_lock)
2568 spin_unlock(&blocked_lock_lock);
2569 lg_global_unlock(&file_lock_lglock);
2572 static const struct seq_operations locks_seq_operations = {
2573 .start = locks_start,
2579 static int locks_open(struct inode *inode, struct file *filp)
2581 return seq_open_private(filp, &locks_seq_operations,
2582 sizeof(struct locks_iterator));
2585 static const struct file_operations proc_locks_operations = {
2588 .llseek = seq_lseek,
2589 .release = seq_release_private,
2592 static int __init proc_locks_init(void)
2594 proc_create("locks", 0, NULL, &proc_locks_operations);
2597 module_init(proc_locks_init);
2601 * lock_may_read - checks that the region is free of locks
2602 * @inode: the inode that is being read
2603 * @start: the first byte to read
2604 * @len: the number of bytes to read
2606 * Emulates Windows locking requirements. Whole-file
2607 * mandatory locks (share modes) can prohibit a read and
2608 * byte-range POSIX locks can prohibit a read if they overlap.
2610 * N.B. this function is only ever called
2611 * from knfsd and ownership of locks is never checked.
2613 int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
2615 struct file_lock *fl;
2618 spin_lock(&inode->i_lock);
2619 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
2621 if (fl->fl_type == F_RDLCK)
2623 if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
2625 } else if (IS_FLOCK(fl)) {
2626 if (!(fl->fl_type & LOCK_MAND))
2628 if (fl->fl_type & LOCK_READ)
2635 spin_unlock(&inode->i_lock);
2639 EXPORT_SYMBOL(lock_may_read);
2642 * lock_may_write - checks that the region is free of locks
2643 * @inode: the inode that is being written
2644 * @start: the first byte to write
2645 * @len: the number of bytes to write
2647 * Emulates Windows locking requirements. Whole-file
2648 * mandatory locks (share modes) can prohibit a write and
2649 * byte-range POSIX locks can prohibit a write if they overlap.
2651 * N.B. this function is only ever called
2652 * from knfsd and ownership of locks is never checked.
2654 int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
2656 struct file_lock *fl;
2659 spin_lock(&inode->i_lock);
2660 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
2662 if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
2664 } else if (IS_FLOCK(fl)) {
2665 if (!(fl->fl_type & LOCK_MAND))
2667 if (fl->fl_type & LOCK_WRITE)
2674 spin_unlock(&inode->i_lock);
2678 EXPORT_SYMBOL(lock_may_write);
2680 static int __init filelock_init(void)
2684 filelock_cache = kmem_cache_create("file_lock_cache",
2685 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2687 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2689 for_each_possible_cpu(i)
2690 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2695 core_initcall(filelock_init);