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/mandatory.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/fs.h>
120 #include <linux/init.h>
121 #include <linux/module.h>
122 #include <linux/security.h>
123 #include <linux/slab.h>
124 #include <linux/smp_lock.h>
125 #include <linux/syscalls.h>
126 #include <linux/time.h>
127 #include <linux/rcupdate.h>
129 #include <asm/semaphore.h>
130 #include <asm/uaccess.h>
132 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
133 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
134 #define IS_LEASE(fl) (fl->fl_flags & FL_LEASE)
136 int leases_enable = 1;
137 int lease_break_time = 45;
139 #define for_each_lock(inode, lockp) \
140 for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
142 static LIST_HEAD(file_lock_list);
143 static LIST_HEAD(blocked_list);
145 static kmem_cache_t *filelock_cache __read_mostly;
147 /* Allocate an empty lock structure. */
148 static struct file_lock *locks_alloc_lock(void)
150 return kmem_cache_alloc(filelock_cache, SLAB_KERNEL);
153 static void locks_release_private(struct file_lock *fl)
156 if (fl->fl_ops->fl_release_private)
157 fl->fl_ops->fl_release_private(fl);
161 if (fl->fl_lmops->fl_release_private)
162 fl->fl_lmops->fl_release_private(fl);
168 /* Free a lock which is not in use. */
169 static void locks_free_lock(struct file_lock *fl)
175 if (waitqueue_active(&fl->fl_wait))
176 panic("Attempting to free lock with active wait queue");
178 if (!list_empty(&fl->fl_block))
179 panic("Attempting to free lock with active block list");
181 if (!list_empty(&fl->fl_link))
182 panic("Attempting to free lock on active lock list");
184 locks_release_private(fl);
185 kmem_cache_free(filelock_cache, fl);
188 void locks_init_lock(struct file_lock *fl)
190 INIT_LIST_HEAD(&fl->fl_link);
191 INIT_LIST_HEAD(&fl->fl_block);
192 init_waitqueue_head(&fl->fl_wait);
194 fl->fl_fasync = NULL;
200 fl->fl_start = fl->fl_end = 0;
205 EXPORT_SYMBOL(locks_init_lock);
208 * Initialises the fields of the file lock which are invariant for
211 static void init_once(void *foo, kmem_cache_t *cache, unsigned long flags)
213 struct file_lock *lock = (struct file_lock *) foo;
215 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) !=
216 SLAB_CTOR_CONSTRUCTOR)
219 locks_init_lock(lock);
222 static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
225 if (fl->fl_ops->fl_copy_lock)
226 fl->fl_ops->fl_copy_lock(new, fl);
227 new->fl_ops = fl->fl_ops;
230 if (fl->fl_lmops->fl_copy_lock)
231 fl->fl_lmops->fl_copy_lock(new, fl);
232 new->fl_lmops = fl->fl_lmops;
237 * Initialize a new lock from an existing file_lock structure.
239 static void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
241 new->fl_owner = fl->fl_owner;
242 new->fl_pid = fl->fl_pid;
244 new->fl_flags = fl->fl_flags;
245 new->fl_type = fl->fl_type;
246 new->fl_start = fl->fl_start;
247 new->fl_end = fl->fl_end;
249 new->fl_lmops = NULL;
252 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
254 locks_release_private(new);
256 __locks_copy_lock(new, fl);
257 new->fl_file = fl->fl_file;
258 new->fl_ops = fl->fl_ops;
259 new->fl_lmops = fl->fl_lmops;
261 locks_copy_private(new, fl);
264 EXPORT_SYMBOL(locks_copy_lock);
266 static inline int flock_translate_cmd(int cmd) {
268 return cmd & (LOCK_MAND | LOCK_RW);
280 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
281 static int flock_make_lock(struct file *filp, struct file_lock **lock,
284 struct file_lock *fl;
285 int type = flock_translate_cmd(cmd);
289 fl = locks_alloc_lock();
294 fl->fl_pid = current->tgid;
295 fl->fl_flags = FL_FLOCK;
297 fl->fl_end = OFFSET_MAX;
303 static int assign_type(struct file_lock *fl, int type)
317 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
320 static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
325 switch (l->l_whence) {
333 start = i_size_read(filp->f_dentry->d_inode);
339 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
340 POSIX-2001 defines it. */
344 fl->fl_end = OFFSET_MAX;
346 end = start + l->l_len - 1;
348 } else if (l->l_len < 0) {
355 fl->fl_start = start; /* we record the absolute position */
356 if (fl->fl_end < fl->fl_start)
359 fl->fl_owner = current->files;
360 fl->fl_pid = current->tgid;
362 fl->fl_flags = FL_POSIX;
366 return assign_type(fl, l->l_type);
369 #if BITS_PER_LONG == 32
370 static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
375 switch (l->l_whence) {
383 start = i_size_read(filp->f_dentry->d_inode);
392 fl->fl_end = OFFSET_MAX;
394 fl->fl_end = start + l->l_len - 1;
395 } else if (l->l_len < 0) {
396 fl->fl_end = start - 1;
401 fl->fl_start = start; /* we record the absolute position */
402 if (fl->fl_end < fl->fl_start)
405 fl->fl_owner = current->files;
406 fl->fl_pid = current->tgid;
408 fl->fl_flags = FL_POSIX;
416 fl->fl_type = l->l_type;
426 /* default lease lock manager operations */
427 static void lease_break_callback(struct file_lock *fl)
429 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
432 static void lease_release_private_callback(struct file_lock *fl)
437 f_delown(fl->fl_file);
438 fl->fl_file->f_owner.signum = 0;
441 static int lease_mylease_callback(struct file_lock *fl, struct file_lock *try)
443 return fl->fl_file == try->fl_file;
446 static struct lock_manager_operations lease_manager_ops = {
447 .fl_break = lease_break_callback,
448 .fl_release_private = lease_release_private_callback,
449 .fl_mylease = lease_mylease_callback,
450 .fl_change = lease_modify,
454 * Initialize a lease, use the default lock manager operations
456 static int lease_init(struct file *filp, int type, struct file_lock *fl)
458 fl->fl_owner = current->files;
459 fl->fl_pid = current->tgid;
462 fl->fl_flags = FL_LEASE;
463 if (assign_type(fl, type) != 0) {
468 fl->fl_end = OFFSET_MAX;
470 fl->fl_lmops = &lease_manager_ops;
474 /* Allocate a file_lock initialised to this type of lease */
475 static int lease_alloc(struct file *filp, int type, struct file_lock **flp)
477 struct file_lock *fl = locks_alloc_lock();
483 error = lease_init(filp, type, fl);
490 /* Check if two locks overlap each other.
492 static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
494 return ((fl1->fl_end >= fl2->fl_start) &&
495 (fl2->fl_end >= fl1->fl_start));
499 * Check whether two locks have the same owner.
501 static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
503 if (fl1->fl_lmops && fl1->fl_lmops->fl_compare_owner)
504 return fl2->fl_lmops == fl1->fl_lmops &&
505 fl1->fl_lmops->fl_compare_owner(fl1, fl2);
506 return fl1->fl_owner == fl2->fl_owner;
509 /* Remove waiter from blocker's block list.
510 * When blocker ends up pointing to itself then the list is empty.
512 static void __locks_delete_block(struct file_lock *waiter)
514 list_del_init(&waiter->fl_block);
515 list_del_init(&waiter->fl_link);
516 waiter->fl_next = NULL;
521 static void locks_delete_block(struct file_lock *waiter)
524 __locks_delete_block(waiter);
528 /* Insert waiter into blocker's block list.
529 * We use a circular list so that processes can be easily woken up in
530 * the order they blocked. The documentation doesn't require this but
531 * it seems like the reasonable thing to do.
533 static void locks_insert_block(struct file_lock *blocker,
534 struct file_lock *waiter)
536 if (!list_empty(&waiter->fl_block)) {
537 printk(KERN_ERR "locks_insert_block: removing duplicated lock "
538 "(pid=%d %Ld-%Ld type=%d)\n", waiter->fl_pid,
539 waiter->fl_start, waiter->fl_end, waiter->fl_type);
540 __locks_delete_block(waiter);
542 list_add_tail(&waiter->fl_block, &blocker->fl_block);
543 waiter->fl_next = blocker;
544 if (IS_POSIX(blocker))
545 list_add(&waiter->fl_link, &blocked_list);
548 /* Wake up processes blocked waiting for blocker.
549 * If told to wait then schedule the processes until the block list
550 * is empty, otherwise empty the block list ourselves.
552 static void locks_wake_up_blocks(struct file_lock *blocker)
554 while (!list_empty(&blocker->fl_block)) {
555 struct file_lock *waiter = list_entry(blocker->fl_block.next,
556 struct file_lock, fl_block);
557 __locks_delete_block(waiter);
558 if (waiter->fl_lmops && waiter->fl_lmops->fl_notify)
559 waiter->fl_lmops->fl_notify(waiter);
561 wake_up(&waiter->fl_wait);
565 /* Insert file lock fl into an inode's lock list at the position indicated
566 * by pos. At the same time add the lock to the global file lock list.
568 static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
570 list_add(&fl->fl_link, &file_lock_list);
572 /* insert into file's list */
576 if (fl->fl_ops && fl->fl_ops->fl_insert)
577 fl->fl_ops->fl_insert(fl);
581 * Delete a lock and then free it.
582 * Wake up processes that are blocked waiting for this lock,
583 * notify the FS that the lock has been cleared and
584 * finally free the lock.
586 static void locks_delete_lock(struct file_lock **thisfl_p)
588 struct file_lock *fl = *thisfl_p;
590 *thisfl_p = fl->fl_next;
592 list_del_init(&fl->fl_link);
594 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
595 if (fl->fl_fasync != NULL) {
596 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
597 fl->fl_fasync = NULL;
600 if (fl->fl_ops && fl->fl_ops->fl_remove)
601 fl->fl_ops->fl_remove(fl);
603 locks_wake_up_blocks(fl);
607 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
608 * checks for shared/exclusive status of overlapping locks.
610 static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
612 if (sys_fl->fl_type == F_WRLCK)
614 if (caller_fl->fl_type == F_WRLCK)
619 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
620 * checking before calling the locks_conflict().
622 static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
624 /* POSIX locks owned by the same process do not conflict with
627 if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl))
630 /* Check whether they overlap */
631 if (!locks_overlap(caller_fl, sys_fl))
634 return (locks_conflict(caller_fl, sys_fl));
637 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
638 * checking before calling the locks_conflict().
640 static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
642 /* FLOCK locks referring to the same filp do not conflict with
645 if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
647 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
650 return (locks_conflict(caller_fl, sys_fl));
653 static int interruptible_sleep_on_locked(wait_queue_head_t *fl_wait, int timeout)
656 DECLARE_WAITQUEUE(wait, current);
658 __set_current_state(TASK_INTERRUPTIBLE);
659 add_wait_queue(fl_wait, &wait);
663 result = schedule_timeout(timeout);
664 if (signal_pending(current))
665 result = -ERESTARTSYS;
666 remove_wait_queue(fl_wait, &wait);
667 __set_current_state(TASK_RUNNING);
671 static int locks_block_on_timeout(struct file_lock *blocker, struct file_lock *waiter, int time)
674 locks_insert_block(blocker, waiter);
675 result = interruptible_sleep_on_locked(&waiter->fl_wait, time);
676 __locks_delete_block(waiter);
681 posix_test_lock(struct file *filp, struct file_lock *fl,
682 struct file_lock *conflock)
684 struct file_lock *cfl;
687 for (cfl = filp->f_dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) {
690 if (posix_locks_conflict(cfl, fl))
694 __locks_copy_lock(conflock, cfl);
702 EXPORT_SYMBOL(posix_test_lock);
704 /* This function tests for deadlock condition before putting a process to
705 * sleep. The detection scheme is no longer recursive. Recursive was neat,
706 * but dangerous - we risked stack corruption if the lock data was bad, or
707 * if the recursion was too deep for any other reason.
709 * We rely on the fact that a task can only be on one lock's wait queue
710 * at a time. When we find blocked_task on a wait queue we can re-search
711 * with blocked_task equal to that queue's owner, until either blocked_task
712 * isn't found, or blocked_task is found on a queue owned by my_task.
714 * Note: the above assumption may not be true when handling lock requests
715 * from a broken NFS client. But broken NFS clients have a lot more to
716 * worry about than proper deadlock detection anyway... --okir
718 int posix_locks_deadlock(struct file_lock *caller_fl,
719 struct file_lock *block_fl)
721 struct list_head *tmp;
724 if (posix_same_owner(caller_fl, block_fl))
726 list_for_each(tmp, &blocked_list) {
727 struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
728 if (posix_same_owner(fl, block_fl)) {
737 EXPORT_SYMBOL(posix_locks_deadlock);
739 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
740 * at the head of the list, but that's secret knowledge known only to
741 * flock_lock_file and posix_lock_file.
743 static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
745 struct file_lock **before;
746 struct inode * inode = filp->f_dentry->d_inode;
751 for_each_lock(inode, before) {
752 struct file_lock *fl = *before;
757 if (filp != fl->fl_file)
759 if (new_fl->fl_type == fl->fl_type)
762 locks_delete_lock(before);
767 if (new_fl->fl_type == F_UNLCK)
771 * If a higher-priority process was blocked on the old file lock,
772 * give it the opportunity to lock the file.
778 for_each_lock(inode, before) {
779 struct file_lock *fl = *before;
784 if (!flock_locks_conflict(new_fl, fl))
787 if (new_fl->fl_flags & FL_SLEEP) {
788 locks_insert_block(fl, new_fl);
792 locks_insert_lock(&inode->i_flock, new_fl);
800 EXPORT_SYMBOL(posix_lock_file);
802 static int __posix_lock_file(struct inode *inode, struct file_lock *request)
804 struct file_lock *fl;
805 struct file_lock *new_fl, *new_fl2;
806 struct file_lock *left = NULL;
807 struct file_lock *right = NULL;
808 struct file_lock **before;
809 int error, added = 0;
812 * We may need two file_lock structures for this operation,
813 * so we get them in advance to avoid races.
815 new_fl = locks_alloc_lock();
816 new_fl2 = locks_alloc_lock();
819 if (request->fl_type != F_UNLCK) {
820 for_each_lock(inode, before) {
821 struct file_lock *fl = *before;
824 if (!posix_locks_conflict(request, fl))
827 if (!(request->fl_flags & FL_SLEEP))
830 if (posix_locks_deadlock(request, fl))
833 locks_insert_block(fl, request);
838 /* If we're just looking for a conflict, we're done. */
840 if (request->fl_flags & FL_ACCESS)
843 error = -ENOLCK; /* "no luck" */
844 if (!(new_fl && new_fl2))
848 * We've allocated the new locks in advance, so there are no
849 * errors possible (and no blocking operations) from here on.
851 * Find the first old lock with the same owner as the new lock.
854 before = &inode->i_flock;
856 /* First skip locks owned by other processes. */
857 while ((fl = *before) && (!IS_POSIX(fl) ||
858 !posix_same_owner(request, fl))) {
859 before = &fl->fl_next;
862 /* Process locks with this owner. */
863 while ((fl = *before) && posix_same_owner(request, fl)) {
864 /* Detect adjacent or overlapping regions (if same lock type)
866 if (request->fl_type == fl->fl_type) {
867 /* In all comparisons of start vs end, use
868 * "start - 1" rather than "end + 1". If end
869 * is OFFSET_MAX, end + 1 will become negative.
871 if (fl->fl_end < request->fl_start - 1)
873 /* If the next lock in the list has entirely bigger
874 * addresses than the new one, insert the lock here.
876 if (fl->fl_start - 1 > request->fl_end)
879 /* If we come here, the new and old lock are of the
880 * same type and adjacent or overlapping. Make one
881 * lock yielding from the lower start address of both
882 * locks to the higher end address.
884 if (fl->fl_start > request->fl_start)
885 fl->fl_start = request->fl_start;
887 request->fl_start = fl->fl_start;
888 if (fl->fl_end < request->fl_end)
889 fl->fl_end = request->fl_end;
891 request->fl_end = fl->fl_end;
893 locks_delete_lock(before);
900 /* Processing for different lock types is a bit
903 if (fl->fl_end < request->fl_start)
905 if (fl->fl_start > request->fl_end)
907 if (request->fl_type == F_UNLCK)
909 if (fl->fl_start < request->fl_start)
911 /* If the next lock in the list has a higher end
912 * address than the new one, insert the new one here.
914 if (fl->fl_end > request->fl_end) {
918 if (fl->fl_start >= request->fl_start) {
919 /* The new lock completely replaces an old
920 * one (This may happen several times).
923 locks_delete_lock(before);
926 /* Replace the old lock with the new one.
927 * Wake up anybody waiting for the old one,
928 * as the change in lock type might satisfy
931 locks_wake_up_blocks(fl);
932 fl->fl_start = request->fl_start;
933 fl->fl_end = request->fl_end;
934 fl->fl_type = request->fl_type;
935 locks_release_private(fl);
936 locks_copy_private(fl, request);
941 /* Go on to next lock.
944 before = &fl->fl_next;
949 if (request->fl_type == F_UNLCK)
951 locks_copy_lock(new_fl, request);
952 locks_insert_lock(before, new_fl);
957 /* The new lock breaks the old one in two pieces,
958 * so we have to use the second new lock.
962 locks_copy_lock(left, right);
963 locks_insert_lock(before, left);
965 right->fl_start = request->fl_end + 1;
966 locks_wake_up_blocks(right);
969 left->fl_end = request->fl_start - 1;
970 locks_wake_up_blocks(left);
975 * Free any unused locks.
978 locks_free_lock(new_fl);
980 locks_free_lock(new_fl2);
985 * posix_lock_file - Apply a POSIX-style lock to a file
986 * @filp: The file to apply the lock to
987 * @fl: The lock to be applied
989 * Add a POSIX style lock to a file.
990 * We merge adjacent & overlapping locks whenever possible.
991 * POSIX locks are sorted by owner task, then by starting address
993 int posix_lock_file(struct file *filp, struct file_lock *fl)
995 return __posix_lock_file(filp->f_dentry->d_inode, fl);
999 * posix_lock_file_wait - Apply a POSIX-style lock to a file
1000 * @filp: The file to apply the lock to
1001 * @fl: The lock to be applied
1003 * Add a POSIX style lock to a file.
1004 * We merge adjacent & overlapping locks whenever possible.
1005 * POSIX locks are sorted by owner task, then by starting address
1007 int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1012 error = __posix_lock_file(filp->f_dentry->d_inode, fl);
1013 if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
1015 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1019 locks_delete_block(fl);
1024 EXPORT_SYMBOL(posix_lock_file_wait);
1027 * locks_mandatory_locked - Check for an active lock
1028 * @inode: the file to check
1030 * Searches the inode's list of locks to find any POSIX locks which conflict.
1031 * This function is called from locks_verify_locked() only.
1033 int locks_mandatory_locked(struct inode *inode)
1035 fl_owner_t owner = current->files;
1036 struct file_lock *fl;
1039 * Search the lock list for this inode for any POSIX locks.
1042 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
1045 if (fl->fl_owner != owner)
1049 return fl ? -EAGAIN : 0;
1053 * locks_mandatory_area - Check for a conflicting lock
1054 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1056 * @inode: the file to check
1057 * @filp: how the file was opened (if it was)
1058 * @offset: start of area to check
1059 * @count: length of area to check
1061 * Searches the inode's list of locks to find any POSIX locks which conflict.
1062 * This function is called from rw_verify_area() and
1063 * locks_verify_truncate().
1065 int locks_mandatory_area(int read_write, struct inode *inode,
1066 struct file *filp, loff_t offset,
1069 struct file_lock fl;
1072 locks_init_lock(&fl);
1073 fl.fl_owner = current->files;
1074 fl.fl_pid = current->tgid;
1076 fl.fl_flags = FL_POSIX | FL_ACCESS;
1077 if (filp && !(filp->f_flags & O_NONBLOCK))
1078 fl.fl_flags |= FL_SLEEP;
1079 fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1080 fl.fl_start = offset;
1081 fl.fl_end = offset + count - 1;
1084 error = __posix_lock_file(inode, &fl);
1085 if (error != -EAGAIN)
1087 if (!(fl.fl_flags & FL_SLEEP))
1089 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1092 * If we've been sleeping someone might have
1093 * changed the permissions behind our back.
1095 if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
1099 locks_delete_block(&fl);
1106 EXPORT_SYMBOL(locks_mandatory_area);
1108 /* We already had a lease on this file; just change its type */
1109 int lease_modify(struct file_lock **before, int arg)
1111 struct file_lock *fl = *before;
1112 int error = assign_type(fl, arg);
1116 locks_wake_up_blocks(fl);
1118 locks_delete_lock(before);
1122 EXPORT_SYMBOL(lease_modify);
1124 static void time_out_leases(struct inode *inode)
1126 struct file_lock **before;
1127 struct file_lock *fl;
1129 before = &inode->i_flock;
1130 while ((fl = *before) && IS_LEASE(fl) && (fl->fl_type & F_INPROGRESS)) {
1131 if ((fl->fl_break_time == 0)
1132 || time_before(jiffies, fl->fl_break_time)) {
1133 before = &fl->fl_next;
1136 lease_modify(before, fl->fl_type & ~F_INPROGRESS);
1137 if (fl == *before) /* lease_modify may have freed fl */
1138 before = &fl->fl_next;
1143 * __break_lease - revoke all outstanding leases on file
1144 * @inode: the inode of the file to return
1145 * @mode: the open mode (read or write)
1147 * break_lease (inlined for speed) has checked there already
1148 * is a lease on this file. Leases are broken on a call to open()
1149 * or truncate(). This function can sleep unless you
1150 * specified %O_NONBLOCK to your open().
1152 int __break_lease(struct inode *inode, unsigned int mode)
1154 int error = 0, future;
1155 struct file_lock *new_fl, *flock;
1156 struct file_lock *fl;
1158 unsigned long break_time;
1159 int i_have_this_lease = 0;
1161 alloc_err = lease_alloc(NULL, mode & FMODE_WRITE ? F_WRLCK : F_RDLCK,
1166 time_out_leases(inode);
1168 flock = inode->i_flock;
1169 if ((flock == NULL) || !IS_LEASE(flock))
1172 for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next)
1173 if (fl->fl_owner == current->files)
1174 i_have_this_lease = 1;
1176 if (mode & FMODE_WRITE) {
1177 /* If we want write access, we have to revoke any lease. */
1178 future = F_UNLCK | F_INPROGRESS;
1179 } else if (flock->fl_type & F_INPROGRESS) {
1180 /* If the lease is already being broken, we just leave it */
1181 future = flock->fl_type;
1182 } else if (flock->fl_type & F_WRLCK) {
1183 /* Downgrade the exclusive lease to a read-only lease. */
1184 future = F_RDLCK | F_INPROGRESS;
1186 /* the existing lease was read-only, so we can read too. */
1190 if (alloc_err && !i_have_this_lease && ((mode & O_NONBLOCK) == 0)) {
1196 if (lease_break_time > 0) {
1197 break_time = jiffies + lease_break_time * HZ;
1198 if (break_time == 0)
1199 break_time++; /* so that 0 means no break time */
1202 for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
1203 if (fl->fl_type != future) {
1204 fl->fl_type = future;
1205 fl->fl_break_time = break_time;
1206 /* lease must have lmops break callback */
1207 fl->fl_lmops->fl_break(fl);
1211 if (i_have_this_lease || (mode & O_NONBLOCK)) {
1212 error = -EWOULDBLOCK;
1217 break_time = flock->fl_break_time;
1218 if (break_time != 0) {
1219 break_time -= jiffies;
1220 if (break_time == 0)
1223 error = locks_block_on_timeout(flock, new_fl, break_time);
1226 time_out_leases(inode);
1227 /* Wait for the next lease that has not been broken yet */
1228 for (flock = inode->i_flock; flock && IS_LEASE(flock);
1229 flock = flock->fl_next) {
1230 if (flock->fl_type & F_INPROGRESS)
1239 locks_free_lock(new_fl);
1243 EXPORT_SYMBOL(__break_lease);
1248 * @time: pointer to a timespec which will contain the last modified time
1250 * This is to force NFS clients to flush their caches for files with
1251 * exclusive leases. The justification is that if someone has an
1252 * exclusive lease, then they could be modifiying it.
1254 void lease_get_mtime(struct inode *inode, struct timespec *time)
1256 struct file_lock *flock = inode->i_flock;
1257 if (flock && IS_LEASE(flock) && (flock->fl_type & F_WRLCK))
1258 *time = current_fs_time(inode->i_sb);
1260 *time = inode->i_mtime;
1263 EXPORT_SYMBOL(lease_get_mtime);
1266 * fcntl_getlease - Enquire what lease is currently active
1269 * The value returned by this function will be one of
1270 * (if no lease break is pending):
1272 * %F_RDLCK to indicate a shared lease is held.
1274 * %F_WRLCK to indicate an exclusive lease is held.
1276 * %F_UNLCK to indicate no lease is held.
1278 * (if a lease break is pending):
1280 * %F_RDLCK to indicate an exclusive lease needs to be
1281 * changed to a shared lease (or removed).
1283 * %F_UNLCK to indicate the lease needs to be removed.
1285 * XXX: sfr & willy disagree over whether F_INPROGRESS
1286 * should be returned to userspace.
1288 int fcntl_getlease(struct file *filp)
1290 struct file_lock *fl;
1294 time_out_leases(filp->f_dentry->d_inode);
1295 for (fl = filp->f_dentry->d_inode->i_flock; fl && IS_LEASE(fl);
1297 if (fl->fl_file == filp) {
1298 type = fl->fl_type & ~F_INPROGRESS;
1307 * __setlease - sets a lease on an open file
1308 * @filp: file pointer
1309 * @arg: type of lease to obtain
1310 * @flp: input - file_lock to use, output - file_lock inserted
1312 * The (input) flp->fl_lmops->fl_break function is required
1315 * Called with kernel lock held.
1317 static int __setlease(struct file *filp, long arg, struct file_lock **flp)
1319 struct file_lock *fl, **before, **my_before = NULL, *lease;
1320 struct dentry *dentry = filp->f_dentry;
1321 struct inode *inode = dentry->d_inode;
1322 int error, rdlease_count = 0, wrlease_count = 0;
1324 time_out_leases(inode);
1327 if (!flp || !(*flp) || !(*flp)->fl_lmops || !(*flp)->fl_lmops->fl_break)
1333 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1335 if ((arg == F_WRLCK)
1336 && ((atomic_read(&dentry->d_count) > 1)
1337 || (atomic_read(&inode->i_count) > 1)))
1341 * At this point, we know that if there is an exclusive
1342 * lease on this file, then we hold it on this filp
1343 * (otherwise our open of this file would have blocked).
1344 * And if we are trying to acquire an exclusive lease,
1345 * then the file is not open by anyone (including us)
1346 * except for this filp.
1348 for (before = &inode->i_flock;
1349 ((fl = *before) != NULL) && IS_LEASE(fl);
1350 before = &fl->fl_next) {
1351 if (lease->fl_lmops->fl_mylease(fl, lease))
1353 else if (fl->fl_type == (F_INPROGRESS | F_UNLCK))
1355 * Someone is in the process of opening this
1356 * file for writing so we may not take an
1357 * exclusive lease on it.
1364 if ((arg == F_RDLCK && (wrlease_count > 0)) ||
1365 (arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0)))
1368 if (my_before != NULL) {
1369 error = lease->fl_lmops->fl_change(my_before, arg);
1381 error = lease_alloc(filp, arg, &fl);
1385 locks_copy_lock(fl, lease);
1387 locks_insert_lock(before, fl);
1395 * setlease - sets a lease on an open file
1396 * @filp: file pointer
1397 * @arg: type of lease to obtain
1398 * @lease: file_lock to use
1400 * Call this to establish a lease on the file.
1401 * The fl_lmops fl_break function is required by break_lease
1404 int setlease(struct file *filp, long arg, struct file_lock **lease)
1406 struct dentry *dentry = filp->f_dentry;
1407 struct inode *inode = dentry->d_inode;
1410 if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE))
1412 if (!S_ISREG(inode->i_mode))
1414 error = security_file_lock(filp, arg);
1419 error = __setlease(filp, arg, lease);
1425 EXPORT_SYMBOL(setlease);
1428 * fcntl_setlease - sets a lease on an open file
1429 * @fd: open file descriptor
1430 * @filp: file pointer
1431 * @arg: type of lease to obtain
1433 * Call this fcntl to establish a lease on the file.
1434 * Note that you also need to call %F_SETSIG to
1435 * receive a signal when the lease is broken.
1437 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1439 struct file_lock fl, *flp = &fl;
1440 struct dentry *dentry = filp->f_dentry;
1441 struct inode *inode = dentry->d_inode;
1444 if ((current->fsuid != inode->i_uid) && !capable(CAP_LEASE))
1446 if (!S_ISREG(inode->i_mode))
1448 error = security_file_lock(filp, arg);
1452 locks_init_lock(&fl);
1453 error = lease_init(filp, arg, &fl);
1459 error = __setlease(filp, arg, &flp);
1460 if (error || arg == F_UNLCK)
1463 error = fasync_helper(fd, filp, 1, &flp->fl_fasync);
1465 /* remove lease just inserted by __setlease */
1466 flp->fl_type = F_UNLCK | F_INPROGRESS;
1467 flp->fl_break_time = jiffies- 10;
1468 time_out_leases(inode);
1472 error = f_setown(filp, current->pid, 0);
1479 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1480 * @filp: The file to apply the lock to
1481 * @fl: The lock to be applied
1483 * Add a FLOCK style lock to a file.
1485 int flock_lock_file_wait(struct file *filp, struct file_lock *fl)
1490 error = flock_lock_file(filp, fl);
1491 if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
1493 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1497 locks_delete_block(fl);
1503 EXPORT_SYMBOL(flock_lock_file_wait);
1506 * sys_flock: - flock() system call.
1507 * @fd: the file descriptor to lock.
1508 * @cmd: the type of lock to apply.
1510 * Apply a %FL_FLOCK style lock to an open file descriptor.
1511 * The @cmd can be one of
1513 * %LOCK_SH -- a shared lock.
1515 * %LOCK_EX -- an exclusive lock.
1517 * %LOCK_UN -- remove an existing lock.
1519 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1521 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1522 * processes read and write access respectively.
1524 asmlinkage long sys_flock(unsigned int fd, unsigned int cmd)
1527 struct file_lock *lock;
1528 int can_sleep, unlock;
1536 can_sleep = !(cmd & LOCK_NB);
1538 unlock = (cmd == LOCK_UN);
1540 if (!unlock && !(cmd & LOCK_MAND) && !(filp->f_mode & 3))
1543 error = flock_make_lock(filp, &lock, cmd);
1547 lock->fl_flags |= FL_SLEEP;
1549 error = security_file_lock(filp, cmd);
1553 if (filp->f_op && filp->f_op->flock)
1554 error = filp->f_op->flock(filp,
1555 (can_sleep) ? F_SETLKW : F_SETLK,
1558 error = flock_lock_file_wait(filp, lock);
1561 if (list_empty(&lock->fl_link)) {
1562 locks_free_lock(lock);
1571 /* Report the first existing lock that would conflict with l.
1572 * This implements the F_GETLK command of fcntl().
1574 int fcntl_getlk(struct file *filp, struct flock __user *l)
1576 struct file_lock *fl, cfl, file_lock;
1581 if (copy_from_user(&flock, l, sizeof(flock)))
1584 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
1587 error = flock_to_posix_lock(filp, &file_lock, &flock);
1591 if (filp->f_op && filp->f_op->lock) {
1592 error = filp->f_op->lock(filp, F_GETLK, &file_lock);
1593 if (file_lock.fl_ops && file_lock.fl_ops->fl_release_private)
1594 file_lock.fl_ops->fl_release_private(&file_lock);
1598 fl = (file_lock.fl_type == F_UNLCK ? NULL : &file_lock);
1600 fl = (posix_test_lock(filp, &file_lock, &cfl) ? &cfl : NULL);
1603 flock.l_type = F_UNLCK;
1605 flock.l_pid = fl->fl_pid;
1606 #if BITS_PER_LONG == 32
1608 * Make sure we can represent the posix lock via
1609 * legacy 32bit flock.
1612 if (fl->fl_start > OFFT_OFFSET_MAX)
1614 if ((fl->fl_end != OFFSET_MAX)
1615 && (fl->fl_end > OFFT_OFFSET_MAX))
1618 flock.l_start = fl->fl_start;
1619 flock.l_len = fl->fl_end == OFFSET_MAX ? 0 :
1620 fl->fl_end - fl->fl_start + 1;
1622 flock.l_type = fl->fl_type;
1625 if (!copy_to_user(l, &flock, sizeof(flock)))
1631 /* Apply the lock described by l to an open file descriptor.
1632 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1634 int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
1635 struct flock __user *l)
1637 struct file_lock *file_lock = locks_alloc_lock();
1639 struct inode *inode;
1642 if (file_lock == NULL)
1646 * This might block, so we do it before checking the inode.
1649 if (copy_from_user(&flock, l, sizeof(flock)))
1652 inode = filp->f_dentry->d_inode;
1654 /* Don't allow mandatory locks on files that may be memory mapped
1657 if (IS_MANDLOCK(inode) &&
1658 (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
1659 mapping_writably_mapped(filp->f_mapping)) {
1665 error = flock_to_posix_lock(filp, file_lock, &flock);
1668 if (cmd == F_SETLKW) {
1669 file_lock->fl_flags |= FL_SLEEP;
1673 switch (flock.l_type) {
1675 if (!(filp->f_mode & FMODE_READ))
1679 if (!(filp->f_mode & FMODE_WRITE))
1689 error = security_file_lock(filp, file_lock->fl_type);
1693 if (filp->f_op && filp->f_op->lock != NULL)
1694 error = filp->f_op->lock(filp, cmd, file_lock);
1697 error = __posix_lock_file(inode, file_lock);
1698 if ((error != -EAGAIN) || (cmd == F_SETLK))
1700 error = wait_event_interruptible(file_lock->fl_wait,
1701 !file_lock->fl_next);
1705 locks_delete_block(file_lock);
1711 * Attempt to detect a close/fcntl race and recover by
1712 * releasing the lock that was just acquired.
1714 if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
1715 flock.l_type = F_UNLCK;
1720 locks_free_lock(file_lock);
1724 #if BITS_PER_LONG == 32
1725 /* Report the first existing lock that would conflict with l.
1726 * This implements the F_GETLK command of fcntl().
1728 int fcntl_getlk64(struct file *filp, struct flock64 __user *l)
1730 struct file_lock *fl, cfl, file_lock;
1731 struct flock64 flock;
1735 if (copy_from_user(&flock, l, sizeof(flock)))
1738 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
1741 error = flock64_to_posix_lock(filp, &file_lock, &flock);
1745 if (filp->f_op && filp->f_op->lock) {
1746 error = filp->f_op->lock(filp, F_GETLK, &file_lock);
1747 if (file_lock.fl_ops && file_lock.fl_ops->fl_release_private)
1748 file_lock.fl_ops->fl_release_private(&file_lock);
1752 fl = (file_lock.fl_type == F_UNLCK ? NULL : &file_lock);
1754 fl = (posix_test_lock(filp, &file_lock, &cfl) ? &cfl : NULL);
1757 flock.l_type = F_UNLCK;
1759 flock.l_pid = fl->fl_pid;
1760 flock.l_start = fl->fl_start;
1761 flock.l_len = fl->fl_end == OFFSET_MAX ? 0 :
1762 fl->fl_end - fl->fl_start + 1;
1764 flock.l_type = fl->fl_type;
1767 if (!copy_to_user(l, &flock, sizeof(flock)))
1774 /* Apply the lock described by l to an open file descriptor.
1775 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1777 int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
1778 struct flock64 __user *l)
1780 struct file_lock *file_lock = locks_alloc_lock();
1781 struct flock64 flock;
1782 struct inode *inode;
1785 if (file_lock == NULL)
1789 * This might block, so we do it before checking the inode.
1792 if (copy_from_user(&flock, l, sizeof(flock)))
1795 inode = filp->f_dentry->d_inode;
1797 /* Don't allow mandatory locks on files that may be memory mapped
1800 if (IS_MANDLOCK(inode) &&
1801 (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
1802 mapping_writably_mapped(filp->f_mapping)) {
1808 error = flock64_to_posix_lock(filp, file_lock, &flock);
1811 if (cmd == F_SETLKW64) {
1812 file_lock->fl_flags |= FL_SLEEP;
1816 switch (flock.l_type) {
1818 if (!(filp->f_mode & FMODE_READ))
1822 if (!(filp->f_mode & FMODE_WRITE))
1832 error = security_file_lock(filp, file_lock->fl_type);
1836 if (filp->f_op && filp->f_op->lock != NULL)
1837 error = filp->f_op->lock(filp, cmd, file_lock);
1840 error = __posix_lock_file(inode, file_lock);
1841 if ((error != -EAGAIN) || (cmd == F_SETLK64))
1843 error = wait_event_interruptible(file_lock->fl_wait,
1844 !file_lock->fl_next);
1848 locks_delete_block(file_lock);
1854 * Attempt to detect a close/fcntl race and recover by
1855 * releasing the lock that was just acquired.
1857 if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
1858 flock.l_type = F_UNLCK;
1863 locks_free_lock(file_lock);
1866 #endif /* BITS_PER_LONG == 32 */
1869 * This function is called when the file is being removed
1870 * from the task's fd array. POSIX locks belonging to this task
1871 * are deleted at this time.
1873 void locks_remove_posix(struct file *filp, fl_owner_t owner)
1875 struct file_lock lock, **before;
1878 * If there are no locks held on this file, we don't need to call
1879 * posix_lock_file(). Another process could be setting a lock on this
1880 * file at the same time, but we wouldn't remove that lock anyway.
1882 before = &filp->f_dentry->d_inode->i_flock;
1883 if (*before == NULL)
1886 lock.fl_type = F_UNLCK;
1887 lock.fl_flags = FL_POSIX;
1889 lock.fl_end = OFFSET_MAX;
1890 lock.fl_owner = owner;
1891 lock.fl_pid = current->tgid;
1892 lock.fl_file = filp;
1894 lock.fl_lmops = NULL;
1896 if (filp->f_op && filp->f_op->lock != NULL) {
1897 filp->f_op->lock(filp, F_SETLK, &lock);
1901 /* Can't use posix_lock_file here; we need to remove it no matter
1902 * which pid we have.
1905 while (*before != NULL) {
1906 struct file_lock *fl = *before;
1907 if (IS_POSIX(fl) && posix_same_owner(fl, &lock)) {
1908 locks_delete_lock(before);
1911 before = &fl->fl_next;
1915 if (lock.fl_ops && lock.fl_ops->fl_release_private)
1916 lock.fl_ops->fl_release_private(&lock);
1919 EXPORT_SYMBOL(locks_remove_posix);
1922 * This function is called on the last close of an open file.
1924 void locks_remove_flock(struct file *filp)
1926 struct inode * inode = filp->f_dentry->d_inode;
1927 struct file_lock *fl;
1928 struct file_lock **before;
1930 if (!inode->i_flock)
1933 if (filp->f_op && filp->f_op->flock) {
1934 struct file_lock fl = {
1935 .fl_pid = current->tgid,
1937 .fl_flags = FL_FLOCK,
1939 .fl_end = OFFSET_MAX,
1941 filp->f_op->flock(filp, F_SETLKW, &fl);
1942 if (fl.fl_ops && fl.fl_ops->fl_release_private)
1943 fl.fl_ops->fl_release_private(&fl);
1947 before = &inode->i_flock;
1949 while ((fl = *before) != NULL) {
1950 if (fl->fl_file == filp) {
1952 locks_delete_lock(before);
1956 lease_modify(before, F_UNLCK);
1962 before = &fl->fl_next;
1968 * posix_unblock_lock - stop waiting for a file lock
1969 * @filp: how the file was opened
1970 * @waiter: the lock which was waiting
1972 * lockd needs to block waiting for locks.
1975 posix_unblock_lock(struct file *filp, struct file_lock *waiter)
1980 if (waiter->fl_next)
1981 __locks_delete_block(waiter);
1988 EXPORT_SYMBOL(posix_unblock_lock);
1990 static void lock_get_status(char* out, struct file_lock *fl, int id, char *pfx)
1992 struct inode *inode = NULL;
1994 if (fl->fl_file != NULL)
1995 inode = fl->fl_file->f_dentry->d_inode;
1997 out += sprintf(out, "%d:%s ", id, pfx);
1999 out += sprintf(out, "%6s %s ",
2000 (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
2001 (inode == NULL) ? "*NOINODE*" :
2002 (IS_MANDLOCK(inode) &&
2003 (inode->i_mode & (S_IXGRP | S_ISGID)) == S_ISGID) ?
2004 "MANDATORY" : "ADVISORY ");
2005 } else if (IS_FLOCK(fl)) {
2006 if (fl->fl_type & LOCK_MAND) {
2007 out += sprintf(out, "FLOCK MSNFS ");
2009 out += sprintf(out, "FLOCK ADVISORY ");
2011 } else if (IS_LEASE(fl)) {
2012 out += sprintf(out, "LEASE ");
2013 if (fl->fl_type & F_INPROGRESS)
2014 out += sprintf(out, "BREAKING ");
2015 else if (fl->fl_file)
2016 out += sprintf(out, "ACTIVE ");
2018 out += sprintf(out, "BREAKER ");
2020 out += sprintf(out, "UNKNOWN UNKNOWN ");
2022 if (fl->fl_type & LOCK_MAND) {
2023 out += sprintf(out, "%s ",
2024 (fl->fl_type & LOCK_READ)
2025 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2026 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2028 out += sprintf(out, "%s ",
2029 (fl->fl_type & F_INPROGRESS)
2030 ? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ "
2031 : (fl->fl_type & F_WRLCK) ? "WRITE" : "READ ");
2034 #ifdef WE_CAN_BREAK_LSLK_NOW
2035 out += sprintf(out, "%d %s:%ld ", fl->fl_pid,
2036 inode->i_sb->s_id, inode->i_ino);
2038 /* userspace relies on this representation of dev_t ;-( */
2039 out += sprintf(out, "%d %02x:%02x:%ld ", fl->fl_pid,
2040 MAJOR(inode->i_sb->s_dev),
2041 MINOR(inode->i_sb->s_dev), inode->i_ino);
2044 out += sprintf(out, "%d <none>:0 ", fl->fl_pid);
2047 if (fl->fl_end == OFFSET_MAX)
2048 out += sprintf(out, "%Ld EOF\n", fl->fl_start);
2050 out += sprintf(out, "%Ld %Ld\n", fl->fl_start,
2053 out += sprintf(out, "0 EOF\n");
2057 static void move_lock_status(char **p, off_t* pos, off_t offset)
2061 if(*pos >= offset) {
2062 /* the complete line is valid */
2067 if(*pos+len > offset) {
2068 /* use the second part of the line */
2069 int i = offset-*pos;
2070 memmove(*p,*p+i,len-i);
2075 /* discard the complete line */
2080 * get_locks_status - reports lock usage in /proc/locks
2081 * @buffer: address in userspace to write into
2083 * @offset: how far we are through the buffer
2084 * @length: how much to read
2087 int get_locks_status(char *buffer, char **start, off_t offset, int length)
2089 struct list_head *tmp;
2095 list_for_each(tmp, &file_lock_list) {
2096 struct list_head *btmp;
2097 struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
2098 lock_get_status(q, fl, ++i, "");
2099 move_lock_status(&q, &pos, offset);
2101 if(pos >= offset+length)
2104 list_for_each(btmp, &fl->fl_block) {
2105 struct file_lock *bfl = list_entry(btmp,
2106 struct file_lock, fl_block);
2107 lock_get_status(q, bfl, i, " ->");
2108 move_lock_status(&q, &pos, offset);
2110 if(pos >= offset+length)
2117 if(q-buffer < length)
2123 * lock_may_read - checks that the region is free of locks
2124 * @inode: the inode that is being read
2125 * @start: the first byte to read
2126 * @len: the number of bytes to read
2128 * Emulates Windows locking requirements. Whole-file
2129 * mandatory locks (share modes) can prohibit a read and
2130 * byte-range POSIX locks can prohibit a read if they overlap.
2132 * N.B. this function is only ever called
2133 * from knfsd and ownership of locks is never checked.
2135 int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
2137 struct file_lock *fl;
2140 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
2142 if (fl->fl_type == F_RDLCK)
2144 if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
2146 } else if (IS_FLOCK(fl)) {
2147 if (!(fl->fl_type & LOCK_MAND))
2149 if (fl->fl_type & LOCK_READ)
2160 EXPORT_SYMBOL(lock_may_read);
2163 * lock_may_write - checks that the region is free of locks
2164 * @inode: the inode that is being written
2165 * @start: the first byte to write
2166 * @len: the number of bytes to write
2168 * Emulates Windows locking requirements. Whole-file
2169 * mandatory locks (share modes) can prohibit a write and
2170 * byte-range POSIX locks can prohibit a write if they overlap.
2172 * N.B. this function is only ever called
2173 * from knfsd and ownership of locks is never checked.
2175 int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
2177 struct file_lock *fl;
2180 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
2182 if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
2184 } else if (IS_FLOCK(fl)) {
2185 if (!(fl->fl_type & LOCK_MAND))
2187 if (fl->fl_type & LOCK_WRITE)
2198 EXPORT_SYMBOL(lock_may_write);
2200 static inline void __steal_locks(struct file *file, fl_owner_t from)
2202 struct inode *inode = file->f_dentry->d_inode;
2203 struct file_lock *fl = inode->i_flock;
2206 if (fl->fl_file == file && fl->fl_owner == from)
2207 fl->fl_owner = current->files;
2212 /* When getting ready for executing a binary, we make sure that current
2213 * has a files_struct on its own. Before dropping the old files_struct,
2214 * we take over ownership of all locks for all file descriptors we own.
2215 * Note that we may accidentally steal a lock for a file that a sibling
2216 * has created since the unshare_files() call.
2218 void steal_locks(fl_owner_t from)
2220 struct files_struct *files = current->files;
2222 struct fdtable *fdt;
2230 fdt = files_fdtable(files);
2234 if (i >= fdt->max_fdset || i >= fdt->max_fds)
2236 set = fdt->open_fds->fds_bits[j++];
2239 struct file *file = fdt->fd[i];
2241 __steal_locks(file, from);
2250 EXPORT_SYMBOL(steal_locks);
2252 static int __init filelock_init(void)
2254 filelock_cache = kmem_cache_create("file_lock_cache",
2255 sizeof(struct file_lock), 0, SLAB_PANIC,
2260 core_initcall(filelock_init);