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 struct kmem_cache
*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
, GFP_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
)
171 BUG_ON(waitqueue_active(&fl
->fl_wait
));
172 BUG_ON(!list_empty(&fl
->fl_block
));
173 BUG_ON(!list_empty(&fl
->fl_link
));
175 locks_release_private(fl
);
176 kmem_cache_free(filelock_cache
, fl
);
179 void locks_init_lock(struct file_lock
*fl
)
181 INIT_LIST_HEAD(&fl
->fl_link
);
182 INIT_LIST_HEAD(&fl
->fl_block
);
183 init_waitqueue_head(&fl
->fl_wait
);
185 fl
->fl_fasync
= NULL
;
191 fl
->fl_start
= fl
->fl_end
= 0;
196 EXPORT_SYMBOL(locks_init_lock
);
199 * Initialises the fields of the file lock which are invariant for
202 static void init_once(void *foo
, struct kmem_cache
*cache
, unsigned long flags
)
204 struct file_lock
*lock
= (struct file_lock
*) foo
;
206 locks_init_lock(lock
);
209 static void locks_copy_private(struct file_lock
*new, struct file_lock
*fl
)
212 if (fl
->fl_ops
->fl_copy_lock
)
213 fl
->fl_ops
->fl_copy_lock(new, fl
);
214 new->fl_ops
= fl
->fl_ops
;
217 if (fl
->fl_lmops
->fl_copy_lock
)
218 fl
->fl_lmops
->fl_copy_lock(new, fl
);
219 new->fl_lmops
= fl
->fl_lmops
;
224 * Initialize a new lock from an existing file_lock structure.
226 static void __locks_copy_lock(struct file_lock
*new, const struct file_lock
*fl
)
228 new->fl_owner
= fl
->fl_owner
;
229 new->fl_pid
= fl
->fl_pid
;
231 new->fl_flags
= fl
->fl_flags
;
232 new->fl_type
= fl
->fl_type
;
233 new->fl_start
= fl
->fl_start
;
234 new->fl_end
= fl
->fl_end
;
236 new->fl_lmops
= NULL
;
239 void locks_copy_lock(struct file_lock
*new, struct file_lock
*fl
)
241 locks_release_private(new);
243 __locks_copy_lock(new, fl
);
244 new->fl_file
= fl
->fl_file
;
245 new->fl_ops
= fl
->fl_ops
;
246 new->fl_lmops
= fl
->fl_lmops
;
248 locks_copy_private(new, fl
);
251 EXPORT_SYMBOL(locks_copy_lock
);
253 static inline int flock_translate_cmd(int cmd
) {
255 return cmd
& (LOCK_MAND
| LOCK_RW
);
267 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
268 static int flock_make_lock(struct file
*filp
, struct file_lock
**lock
,
271 struct file_lock
*fl
;
272 int type
= flock_translate_cmd(cmd
);
276 fl
= locks_alloc_lock();
281 fl
->fl_pid
= current
->tgid
;
282 fl
->fl_flags
= FL_FLOCK
;
284 fl
->fl_end
= OFFSET_MAX
;
290 static int assign_type(struct file_lock
*fl
, int type
)
304 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
307 static int flock_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
312 switch (l
->l_whence
) {
320 start
= i_size_read(filp
->f_path
.dentry
->d_inode
);
326 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
327 POSIX-2001 defines it. */
331 fl
->fl_end
= OFFSET_MAX
;
333 end
= start
+ l
->l_len
- 1;
335 } else if (l
->l_len
< 0) {
342 fl
->fl_start
= start
; /* we record the absolute position */
343 if (fl
->fl_end
< fl
->fl_start
)
346 fl
->fl_owner
= current
->files
;
347 fl
->fl_pid
= current
->tgid
;
349 fl
->fl_flags
= FL_POSIX
;
353 return assign_type(fl
, l
->l_type
);
356 #if BITS_PER_LONG == 32
357 static int flock64_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
362 switch (l
->l_whence
) {
370 start
= i_size_read(filp
->f_path
.dentry
->d_inode
);
379 fl
->fl_end
= OFFSET_MAX
;
381 fl
->fl_end
= start
+ l
->l_len
- 1;
382 } else if (l
->l_len
< 0) {
383 fl
->fl_end
= start
- 1;
388 fl
->fl_start
= start
; /* we record the absolute position */
389 if (fl
->fl_end
< fl
->fl_start
)
392 fl
->fl_owner
= current
->files
;
393 fl
->fl_pid
= current
->tgid
;
395 fl
->fl_flags
= FL_POSIX
;
403 fl
->fl_type
= l
->l_type
;
413 /* default lease lock manager operations */
414 static void lease_break_callback(struct file_lock
*fl
)
416 kill_fasync(&fl
->fl_fasync
, SIGIO
, POLL_MSG
);
419 static void lease_release_private_callback(struct file_lock
*fl
)
424 f_delown(fl
->fl_file
);
425 fl
->fl_file
->f_owner
.signum
= 0;
428 static int lease_mylease_callback(struct file_lock
*fl
, struct file_lock
*try)
430 return fl
->fl_file
== try->fl_file
;
433 static struct lock_manager_operations lease_manager_ops
= {
434 .fl_break
= lease_break_callback
,
435 .fl_release_private
= lease_release_private_callback
,
436 .fl_mylease
= lease_mylease_callback
,
437 .fl_change
= lease_modify
,
441 * Initialize a lease, use the default lock manager operations
443 static int lease_init(struct file
*filp
, int 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
, int 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
->fl_compare_owner
)
491 return fl2
->fl_lmops
== fl1
->fl_lmops
&&
492 fl1
->fl_lmops
->fl_compare_owner(fl1
, fl2
);
493 return fl1
->fl_owner
== fl2
->fl_owner
;
496 /* Remove waiter from blocker's block list.
497 * When blocker ends up pointing to itself then the list is empty.
499 static void __locks_delete_block(struct file_lock
*waiter
)
501 list_del_init(&waiter
->fl_block
);
502 list_del_init(&waiter
->fl_link
);
503 waiter
->fl_next
= NULL
;
508 static void locks_delete_block(struct file_lock
*waiter
)
511 __locks_delete_block(waiter
);
515 /* Insert waiter into blocker's block list.
516 * We use a circular list so that processes can be easily woken up in
517 * the order they blocked. The documentation doesn't require this but
518 * it seems like the reasonable thing to do.
520 static void locks_insert_block(struct file_lock
*blocker
,
521 struct file_lock
*waiter
)
523 BUG_ON(!list_empty(&waiter
->fl_block
));
524 list_add_tail(&waiter
->fl_block
, &blocker
->fl_block
);
525 waiter
->fl_next
= blocker
;
526 if (IS_POSIX(blocker
))
527 list_add(&waiter
->fl_link
, &blocked_list
);
530 /* Wake up processes blocked waiting for blocker.
531 * If told to wait then schedule the processes until the block list
532 * is empty, otherwise empty the block list ourselves.
534 static void locks_wake_up_blocks(struct file_lock
*blocker
)
536 while (!list_empty(&blocker
->fl_block
)) {
537 struct file_lock
*waiter
= list_entry(blocker
->fl_block
.next
,
538 struct file_lock
, fl_block
);
539 __locks_delete_block(waiter
);
540 if (waiter
->fl_lmops
&& waiter
->fl_lmops
->fl_notify
)
541 waiter
->fl_lmops
->fl_notify(waiter
);
543 wake_up(&waiter
->fl_wait
);
547 /* Insert file lock fl into an inode's lock list at the position indicated
548 * by pos. At the same time add the lock to the global file lock list.
550 static void locks_insert_lock(struct file_lock
**pos
, struct file_lock
*fl
)
552 list_add(&fl
->fl_link
, &file_lock_list
);
554 /* insert into file's list */
558 if (fl
->fl_ops
&& fl
->fl_ops
->fl_insert
)
559 fl
->fl_ops
->fl_insert(fl
);
563 * Delete a lock and then free it.
564 * Wake up processes that are blocked waiting for this lock,
565 * notify the FS that the lock has been cleared and
566 * finally free the lock.
568 static void locks_delete_lock(struct file_lock
**thisfl_p
)
570 struct file_lock
*fl
= *thisfl_p
;
572 *thisfl_p
= fl
->fl_next
;
574 list_del_init(&fl
->fl_link
);
576 fasync_helper(0, fl
->fl_file
, 0, &fl
->fl_fasync
);
577 if (fl
->fl_fasync
!= NULL
) {
578 printk(KERN_ERR
"locks_delete_lock: fasync == %p\n", fl
->fl_fasync
);
579 fl
->fl_fasync
= NULL
;
582 if (fl
->fl_ops
&& fl
->fl_ops
->fl_remove
)
583 fl
->fl_ops
->fl_remove(fl
);
585 locks_wake_up_blocks(fl
);
589 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
590 * checks for shared/exclusive status of overlapping locks.
592 static int locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
594 if (sys_fl
->fl_type
== F_WRLCK
)
596 if (caller_fl
->fl_type
== F_WRLCK
)
601 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
602 * checking before calling the locks_conflict().
604 static int posix_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
606 /* POSIX locks owned by the same process do not conflict with
609 if (!IS_POSIX(sys_fl
) || posix_same_owner(caller_fl
, sys_fl
))
612 /* Check whether they overlap */
613 if (!locks_overlap(caller_fl
, sys_fl
))
616 return (locks_conflict(caller_fl
, sys_fl
));
619 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
620 * checking before calling the locks_conflict().
622 static int flock_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
624 /* FLOCK locks referring to the same filp do not conflict with
627 if (!IS_FLOCK(sys_fl
) || (caller_fl
->fl_file
== sys_fl
->fl_file
))
629 if ((caller_fl
->fl_type
& LOCK_MAND
) || (sys_fl
->fl_type
& LOCK_MAND
))
632 return (locks_conflict(caller_fl
, sys_fl
));
635 static int interruptible_sleep_on_locked(wait_queue_head_t
*fl_wait
, int timeout
)
638 DECLARE_WAITQUEUE(wait
, current
);
640 __set_current_state(TASK_INTERRUPTIBLE
);
641 add_wait_queue(fl_wait
, &wait
);
645 result
= schedule_timeout(timeout
);
646 if (signal_pending(current
))
647 result
= -ERESTARTSYS
;
648 remove_wait_queue(fl_wait
, &wait
);
649 __set_current_state(TASK_RUNNING
);
653 static int locks_block_on_timeout(struct file_lock
*blocker
, struct file_lock
*waiter
, int time
)
656 locks_insert_block(blocker
, waiter
);
657 result
= interruptible_sleep_on_locked(&waiter
->fl_wait
, time
);
658 __locks_delete_block(waiter
);
663 posix_test_lock(struct file
*filp
, struct file_lock
*fl
)
665 struct file_lock
*cfl
;
668 for (cfl
= filp
->f_path
.dentry
->d_inode
->i_flock
; cfl
; cfl
= cfl
->fl_next
) {
671 if (posix_locks_conflict(cfl
, fl
))
675 __locks_copy_lock(fl
, cfl
);
679 fl
->fl_type
= F_UNLCK
;
684 EXPORT_SYMBOL(posix_test_lock
);
686 /* This function tests for deadlock condition before putting a process to
687 * sleep. The detection scheme is no longer recursive. Recursive was neat,
688 * but dangerous - we risked stack corruption if the lock data was bad, or
689 * if the recursion was too deep for any other reason.
691 * We rely on the fact that a task can only be on one lock's wait queue
692 * at a time. When we find blocked_task on a wait queue we can re-search
693 * with blocked_task equal to that queue's owner, until either blocked_task
694 * isn't found, or blocked_task is found on a queue owned by my_task.
696 * Note: the above assumption may not be true when handling lock requests
697 * from a broken NFS client. But broken NFS clients have a lot more to
698 * worry about than proper deadlock detection anyway... --okir
700 static int posix_locks_deadlock(struct file_lock
*caller_fl
,
701 struct file_lock
*block_fl
)
703 struct list_head
*tmp
;
706 if (posix_same_owner(caller_fl
, block_fl
))
708 list_for_each(tmp
, &blocked_list
) {
709 struct file_lock
*fl
= list_entry(tmp
, struct file_lock
, fl_link
);
710 if (posix_same_owner(fl
, block_fl
)) {
719 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
720 * at the head of the list, but that's secret knowledge known only to
721 * flock_lock_file and posix_lock_file.
723 * Note that if called with an FL_EXISTS argument, the caller may determine
724 * whether or not a lock was successfully freed by testing the return
727 static int flock_lock_file(struct file
*filp
, struct file_lock
*request
)
729 struct file_lock
*new_fl
= NULL
;
730 struct file_lock
**before
;
731 struct inode
* inode
= filp
->f_path
.dentry
->d_inode
;
736 if (request
->fl_flags
& FL_ACCESS
)
738 for_each_lock(inode
, before
) {
739 struct file_lock
*fl
= *before
;
744 if (filp
!= fl
->fl_file
)
746 if (request
->fl_type
== fl
->fl_type
)
749 locks_delete_lock(before
);
753 if (request
->fl_type
== F_UNLCK
) {
754 if ((request
->fl_flags
& FL_EXISTS
) && !found
)
760 new_fl
= locks_alloc_lock();
764 * If a higher-priority process was blocked on the old file lock,
765 * give it the opportunity to lock the file.
771 for_each_lock(inode
, before
) {
772 struct file_lock
*fl
= *before
;
777 if (!flock_locks_conflict(request
, fl
))
780 if (request
->fl_flags
& FL_SLEEP
)
781 locks_insert_block(fl
, request
);
784 if (request
->fl_flags
& FL_ACCESS
)
786 locks_copy_lock(new_fl
, request
);
787 locks_insert_lock(&inode
->i_flock
, new_fl
);
794 locks_free_lock(new_fl
);
798 static int __posix_lock_file(struct inode
*inode
, struct file_lock
*request
, struct file_lock
*conflock
)
800 struct file_lock
*fl
;
801 struct file_lock
*new_fl
= NULL
;
802 struct file_lock
*new_fl2
= NULL
;
803 struct file_lock
*left
= NULL
;
804 struct file_lock
*right
= NULL
;
805 struct file_lock
**before
;
806 int error
, added
= 0;
809 * We may need two file_lock structures for this operation,
810 * so we get them in advance to avoid races.
812 * In some cases we can be sure, that no new locks will be needed
814 if (!(request
->fl_flags
& FL_ACCESS
) &&
815 (request
->fl_type
!= F_UNLCK
||
816 request
->fl_start
!= 0 || request
->fl_end
!= OFFSET_MAX
)) {
817 new_fl
= locks_alloc_lock();
818 new_fl2
= locks_alloc_lock();
822 if (request
->fl_type
!= F_UNLCK
) {
823 for_each_lock(inode
, before
) {
824 struct file_lock
*fl
= *before
;
827 if (!posix_locks_conflict(request
, fl
))
830 locks_copy_lock(conflock
, fl
);
832 if (!(request
->fl_flags
& FL_SLEEP
))
835 if (posix_locks_deadlock(request
, fl
))
838 locks_insert_block(fl
, request
);
843 /* If we're just looking for a conflict, we're done. */
845 if (request
->fl_flags
& FL_ACCESS
)
849 * Find the first old lock with the same owner as the new lock.
852 before
= &inode
->i_flock
;
854 /* First skip locks owned by other processes. */
855 while ((fl
= *before
) && (!IS_POSIX(fl
) ||
856 !posix_same_owner(request
, fl
))) {
857 before
= &fl
->fl_next
;
860 /* Process locks with this owner. */
861 while ((fl
= *before
) && posix_same_owner(request
, fl
)) {
862 /* Detect adjacent or overlapping regions (if same lock type)
864 if (request
->fl_type
== fl
->fl_type
) {
865 /* In all comparisons of start vs end, use
866 * "start - 1" rather than "end + 1". If end
867 * is OFFSET_MAX, end + 1 will become negative.
869 if (fl
->fl_end
< request
->fl_start
- 1)
871 /* If the next lock in the list has entirely bigger
872 * addresses than the new one, insert the lock here.
874 if (fl
->fl_start
- 1 > request
->fl_end
)
877 /* If we come here, the new and old lock are of the
878 * same type and adjacent or overlapping. Make one
879 * lock yielding from the lower start address of both
880 * locks to the higher end address.
882 if (fl
->fl_start
> request
->fl_start
)
883 fl
->fl_start
= request
->fl_start
;
885 request
->fl_start
= fl
->fl_start
;
886 if (fl
->fl_end
< request
->fl_end
)
887 fl
->fl_end
= request
->fl_end
;
889 request
->fl_end
= fl
->fl_end
;
891 locks_delete_lock(before
);
898 /* Processing for different lock types is a bit
901 if (fl
->fl_end
< request
->fl_start
)
903 if (fl
->fl_start
> request
->fl_end
)
905 if (request
->fl_type
== F_UNLCK
)
907 if (fl
->fl_start
< request
->fl_start
)
909 /* If the next lock in the list has a higher end
910 * address than the new one, insert the new one here.
912 if (fl
->fl_end
> request
->fl_end
) {
916 if (fl
->fl_start
>= request
->fl_start
) {
917 /* The new lock completely replaces an old
918 * one (This may happen several times).
921 locks_delete_lock(before
);
924 /* Replace the old lock with the new one.
925 * Wake up anybody waiting for the old one,
926 * as the change in lock type might satisfy
929 locks_wake_up_blocks(fl
);
930 fl
->fl_start
= request
->fl_start
;
931 fl
->fl_end
= request
->fl_end
;
932 fl
->fl_type
= request
->fl_type
;
933 locks_release_private(fl
);
934 locks_copy_private(fl
, request
);
939 /* Go on to next lock.
942 before
= &fl
->fl_next
;
946 * The above code only modifies existing locks in case of
947 * merging or replacing. If new lock(s) need to be inserted
948 * all modifications are done bellow this, so it's safe yet to
951 error
= -ENOLCK
; /* "no luck" */
952 if (right
&& left
== right
&& !new_fl2
)
957 if (request
->fl_type
== F_UNLCK
) {
958 if (request
->fl_flags
& FL_EXISTS
)
967 locks_copy_lock(new_fl
, request
);
968 locks_insert_lock(before
, new_fl
);
973 /* The new lock breaks the old one in two pieces,
974 * so we have to use the second new lock.
978 locks_copy_lock(left
, right
);
979 locks_insert_lock(before
, left
);
981 right
->fl_start
= request
->fl_end
+ 1;
982 locks_wake_up_blocks(right
);
985 left
->fl_end
= request
->fl_start
- 1;
986 locks_wake_up_blocks(left
);
991 * Free any unused locks.
994 locks_free_lock(new_fl
);
996 locks_free_lock(new_fl2
);
1001 * posix_lock_file - Apply a POSIX-style lock to a file
1002 * @filp: The file to apply the lock to
1003 * @fl: The lock to be applied
1004 * @conflock: Place to return a copy of the conflicting lock, if found.
1006 * Add a POSIX style lock to a file.
1007 * We merge adjacent & overlapping locks whenever possible.
1008 * POSIX locks are sorted by owner task, then by starting address
1010 * Note that if called with an FL_EXISTS argument, the caller may determine
1011 * whether or not a lock was successfully freed by testing the return
1012 * value for -ENOENT.
1014 int posix_lock_file(struct file
*filp
, struct file_lock
*fl
,
1015 struct file_lock
*conflock
)
1017 return __posix_lock_file(filp
->f_path
.dentry
->d_inode
, fl
, conflock
);
1019 EXPORT_SYMBOL(posix_lock_file
);
1022 * posix_lock_file_wait - Apply a POSIX-style lock to a file
1023 * @filp: The file to apply the lock to
1024 * @fl: The lock to be applied
1026 * Add a POSIX style lock to a file.
1027 * We merge adjacent & overlapping locks whenever possible.
1028 * POSIX locks are sorted by owner task, then by starting address
1030 int posix_lock_file_wait(struct file
*filp
, struct file_lock
*fl
)
1035 error
= posix_lock_file(filp
, fl
, NULL
);
1036 if ((error
!= -EAGAIN
) || !(fl
->fl_flags
& FL_SLEEP
))
1038 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
1042 locks_delete_block(fl
);
1047 EXPORT_SYMBOL(posix_lock_file_wait
);
1050 * locks_mandatory_locked - Check for an active lock
1051 * @inode: the file to check
1053 * Searches the inode's list of locks to find any POSIX locks which conflict.
1054 * This function is called from locks_verify_locked() only.
1056 int locks_mandatory_locked(struct inode
*inode
)
1058 fl_owner_t owner
= current
->files
;
1059 struct file_lock
*fl
;
1062 * Search the lock list for this inode for any POSIX locks.
1065 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
1068 if (fl
->fl_owner
!= owner
)
1072 return fl
? -EAGAIN
: 0;
1076 * locks_mandatory_area - Check for a conflicting lock
1077 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1079 * @inode: the file to check
1080 * @filp: how the file was opened (if it was)
1081 * @offset: start of area to check
1082 * @count: length of area to check
1084 * Searches the inode's list of locks to find any POSIX locks which conflict.
1085 * This function is called from rw_verify_area() and
1086 * locks_verify_truncate().
1088 int locks_mandatory_area(int read_write
, struct inode
*inode
,
1089 struct file
*filp
, loff_t offset
,
1092 struct file_lock fl
;
1095 locks_init_lock(&fl
);
1096 fl
.fl_owner
= current
->files
;
1097 fl
.fl_pid
= current
->tgid
;
1099 fl
.fl_flags
= FL_POSIX
| FL_ACCESS
;
1100 if (filp
&& !(filp
->f_flags
& O_NONBLOCK
))
1101 fl
.fl_flags
|= FL_SLEEP
;
1102 fl
.fl_type
= (read_write
== FLOCK_VERIFY_WRITE
) ? F_WRLCK
: F_RDLCK
;
1103 fl
.fl_start
= offset
;
1104 fl
.fl_end
= offset
+ count
- 1;
1107 error
= __posix_lock_file(inode
, &fl
, NULL
);
1108 if (error
!= -EAGAIN
)
1110 if (!(fl
.fl_flags
& FL_SLEEP
))
1112 error
= wait_event_interruptible(fl
.fl_wait
, !fl
.fl_next
);
1115 * If we've been sleeping someone might have
1116 * changed the permissions behind our back.
1118 if ((inode
->i_mode
& (S_ISGID
| S_IXGRP
)) == S_ISGID
)
1122 locks_delete_block(&fl
);
1129 EXPORT_SYMBOL(locks_mandatory_area
);
1131 /* We already had a lease on this file; just change its type */
1132 int lease_modify(struct file_lock
**before
, int arg
)
1134 struct file_lock
*fl
= *before
;
1135 int error
= assign_type(fl
, arg
);
1139 locks_wake_up_blocks(fl
);
1141 locks_delete_lock(before
);
1145 EXPORT_SYMBOL(lease_modify
);
1147 static void time_out_leases(struct inode
*inode
)
1149 struct file_lock
**before
;
1150 struct file_lock
*fl
;
1152 before
= &inode
->i_flock
;
1153 while ((fl
= *before
) && IS_LEASE(fl
) && (fl
->fl_type
& F_INPROGRESS
)) {
1154 if ((fl
->fl_break_time
== 0)
1155 || time_before(jiffies
, fl
->fl_break_time
)) {
1156 before
= &fl
->fl_next
;
1159 lease_modify(before
, fl
->fl_type
& ~F_INPROGRESS
);
1160 if (fl
== *before
) /* lease_modify may have freed fl */
1161 before
= &fl
->fl_next
;
1166 * __break_lease - revoke all outstanding leases on file
1167 * @inode: the inode of the file to return
1168 * @mode: the open mode (read or write)
1170 * break_lease (inlined for speed) has checked there already is at least
1171 * some kind of lock (maybe a lease) on this file. Leases are broken on
1172 * a call to open() or truncate(). This function can sleep unless you
1173 * specified %O_NONBLOCK to your open().
1175 int __break_lease(struct inode
*inode
, unsigned int mode
)
1177 int error
= 0, future
;
1178 struct file_lock
*new_fl
, *flock
;
1179 struct file_lock
*fl
;
1180 unsigned long break_time
;
1181 int i_have_this_lease
= 0;
1183 new_fl
= lease_alloc(NULL
, mode
& FMODE_WRITE
? F_WRLCK
: F_RDLCK
);
1187 time_out_leases(inode
);
1189 flock
= inode
->i_flock
;
1190 if ((flock
== NULL
) || !IS_LEASE(flock
))
1193 for (fl
= flock
; fl
&& IS_LEASE(fl
); fl
= fl
->fl_next
)
1194 if (fl
->fl_owner
== current
->files
)
1195 i_have_this_lease
= 1;
1197 if (mode
& FMODE_WRITE
) {
1198 /* If we want write access, we have to revoke any lease. */
1199 future
= F_UNLCK
| F_INPROGRESS
;
1200 } else if (flock
->fl_type
& F_INPROGRESS
) {
1201 /* If the lease is already being broken, we just leave it */
1202 future
= flock
->fl_type
;
1203 } else if (flock
->fl_type
& F_WRLCK
) {
1204 /* Downgrade the exclusive lease to a read-only lease. */
1205 future
= F_RDLCK
| F_INPROGRESS
;
1207 /* the existing lease was read-only, so we can read too. */
1211 if (IS_ERR(new_fl
) && !i_have_this_lease
1212 && ((mode
& O_NONBLOCK
) == 0)) {
1213 error
= PTR_ERR(new_fl
);
1218 if (lease_break_time
> 0) {
1219 break_time
= jiffies
+ lease_break_time
* HZ
;
1220 if (break_time
== 0)
1221 break_time
++; /* so that 0 means no break time */
1224 for (fl
= flock
; fl
&& IS_LEASE(fl
); fl
= fl
->fl_next
) {
1225 if (fl
->fl_type
!= future
) {
1226 fl
->fl_type
= future
;
1227 fl
->fl_break_time
= break_time
;
1228 /* lease must have lmops break callback */
1229 fl
->fl_lmops
->fl_break(fl
);
1233 if (i_have_this_lease
|| (mode
& O_NONBLOCK
)) {
1234 error
= -EWOULDBLOCK
;
1239 break_time
= flock
->fl_break_time
;
1240 if (break_time
!= 0) {
1241 break_time
-= jiffies
;
1242 if (break_time
== 0)
1245 error
= locks_block_on_timeout(flock
, new_fl
, break_time
);
1248 time_out_leases(inode
);
1249 /* Wait for the next lease that has not been broken yet */
1250 for (flock
= inode
->i_flock
; flock
&& IS_LEASE(flock
);
1251 flock
= flock
->fl_next
) {
1252 if (flock
->fl_type
& F_INPROGRESS
)
1260 if (!IS_ERR(new_fl
))
1261 locks_free_lock(new_fl
);
1265 EXPORT_SYMBOL(__break_lease
);
1270 * @time: pointer to a timespec which will contain the last modified time
1272 * This is to force NFS clients to flush their caches for files with
1273 * exclusive leases. The justification is that if someone has an
1274 * exclusive lease, then they could be modifiying it.
1276 void lease_get_mtime(struct inode
*inode
, struct timespec
*time
)
1278 struct file_lock
*flock
= inode
->i_flock
;
1279 if (flock
&& IS_LEASE(flock
) && (flock
->fl_type
& F_WRLCK
))
1280 *time
= current_fs_time(inode
->i_sb
);
1282 *time
= inode
->i_mtime
;
1285 EXPORT_SYMBOL(lease_get_mtime
);
1288 * fcntl_getlease - Enquire what lease is currently active
1291 * The value returned by this function will be one of
1292 * (if no lease break is pending):
1294 * %F_RDLCK to indicate a shared lease is held.
1296 * %F_WRLCK to indicate an exclusive lease is held.
1298 * %F_UNLCK to indicate no lease is held.
1300 * (if a lease break is pending):
1302 * %F_RDLCK to indicate an exclusive lease needs to be
1303 * changed to a shared lease (or removed).
1305 * %F_UNLCK to indicate the lease needs to be removed.
1307 * XXX: sfr & willy disagree over whether F_INPROGRESS
1308 * should be returned to userspace.
1310 int fcntl_getlease(struct file
*filp
)
1312 struct file_lock
*fl
;
1316 time_out_leases(filp
->f_path
.dentry
->d_inode
);
1317 for (fl
= filp
->f_path
.dentry
->d_inode
->i_flock
; fl
&& IS_LEASE(fl
);
1319 if (fl
->fl_file
== filp
) {
1320 type
= fl
->fl_type
& ~F_INPROGRESS
;
1329 * setlease - sets a lease on an open file
1330 * @filp: file pointer
1331 * @arg: type of lease to obtain
1332 * @flp: input - file_lock to use, output - file_lock inserted
1334 * The (input) flp->fl_lmops->fl_break function is required
1337 * Called with kernel lock held.
1339 static int setlease(struct file
*filp
, long arg
, struct file_lock
**flp
)
1341 struct file_lock
*fl
, **before
, **my_before
= NULL
, *lease
;
1342 struct dentry
*dentry
= filp
->f_path
.dentry
;
1343 struct inode
*inode
= dentry
->d_inode
;
1344 int error
, rdlease_count
= 0, wrlease_count
= 0;
1346 if ((current
->fsuid
!= inode
->i_uid
) && !capable(CAP_LEASE
))
1348 if (!S_ISREG(inode
->i_mode
))
1350 error
= security_file_lock(filp
, arg
);
1354 time_out_leases(inode
);
1356 BUG_ON(!(*flp
)->fl_lmops
->fl_break
);
1361 if ((arg
== F_RDLCK
) && (atomic_read(&inode
->i_writecount
) > 0))
1363 if ((arg
== F_WRLCK
)
1364 && ((atomic_read(&dentry
->d_count
) > 1)
1365 || (atomic_read(&inode
->i_count
) > 1)))
1369 * At this point, we know that if there is an exclusive
1370 * lease on this file, then we hold it on this filp
1371 * (otherwise our open of this file would have blocked).
1372 * And if we are trying to acquire an exclusive lease,
1373 * then the file is not open by anyone (including us)
1374 * except for this filp.
1376 for (before
= &inode
->i_flock
;
1377 ((fl
= *before
) != NULL
) && IS_LEASE(fl
);
1378 before
= &fl
->fl_next
) {
1379 if (lease
->fl_lmops
->fl_mylease(fl
, lease
))
1381 else if (fl
->fl_type
== (F_INPROGRESS
| F_UNLCK
))
1383 * Someone is in the process of opening this
1384 * file for writing so we may not take an
1385 * exclusive lease on it.
1392 if ((arg
== F_RDLCK
&& (wrlease_count
> 0)) ||
1393 (arg
== F_WRLCK
&& ((rdlease_count
+ wrlease_count
) > 0)))
1396 if (my_before
!= NULL
) {
1398 error
= lease
->fl_lmops
->fl_change(my_before
, arg
);
1411 fl
= locks_alloc_lock();
1415 locks_copy_lock(fl
, lease
);
1417 locks_insert_lock(before
, fl
);
1426 * vfs_setlease - sets a lease on an open file
1427 * @filp: file pointer
1428 * @arg: type of lease to obtain
1429 * @lease: file_lock to use
1431 * Call this to establish a lease on the file.
1432 * The fl_lmops fl_break function is required by break_lease
1435 int vfs_setlease(struct file
*filp
, long arg
, struct file_lock
**lease
)
1440 error
= setlease(filp
, arg
, lease
);
1445 EXPORT_SYMBOL_GPL(vfs_setlease
);
1448 * fcntl_setlease - sets a lease on an open file
1449 * @fd: open file descriptor
1450 * @filp: file pointer
1451 * @arg: type of lease to obtain
1453 * Call this fcntl to establish a lease on the file.
1454 * Note that you also need to call %F_SETSIG to
1455 * receive a signal when the lease is broken.
1457 int fcntl_setlease(unsigned int fd
, struct file
*filp
, long arg
)
1459 struct file_lock fl
, *flp
= &fl
;
1460 struct dentry
*dentry
= filp
->f_path
.dentry
;
1461 struct inode
*inode
= dentry
->d_inode
;
1464 locks_init_lock(&fl
);
1465 error
= lease_init(filp
, arg
, &fl
);
1471 error
= vfs_setlease(filp
, arg
, &flp
);
1472 if (error
|| arg
== F_UNLCK
)
1475 error
= fasync_helper(fd
, filp
, 1, &flp
->fl_fasync
);
1477 /* remove lease just inserted by setlease */
1478 flp
->fl_type
= F_UNLCK
| F_INPROGRESS
;
1479 flp
->fl_break_time
= jiffies
- 10;
1480 time_out_leases(inode
);
1484 error
= __f_setown(filp
, task_pid(current
), PIDTYPE_PID
, 0);
1491 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1492 * @filp: The file to apply the lock to
1493 * @fl: The lock to be applied
1495 * Add a FLOCK style lock to a file.
1497 int flock_lock_file_wait(struct file
*filp
, struct file_lock
*fl
)
1502 error
= flock_lock_file(filp
, fl
);
1503 if ((error
!= -EAGAIN
) || !(fl
->fl_flags
& FL_SLEEP
))
1505 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
1509 locks_delete_block(fl
);
1515 EXPORT_SYMBOL(flock_lock_file_wait
);
1518 * sys_flock: - flock() system call.
1519 * @fd: the file descriptor to lock.
1520 * @cmd: the type of lock to apply.
1522 * Apply a %FL_FLOCK style lock to an open file descriptor.
1523 * The @cmd can be one of
1525 * %LOCK_SH -- a shared lock.
1527 * %LOCK_EX -- an exclusive lock.
1529 * %LOCK_UN -- remove an existing lock.
1531 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1533 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1534 * processes read and write access respectively.
1536 asmlinkage
long sys_flock(unsigned int fd
, unsigned int cmd
)
1539 struct file_lock
*lock
;
1540 int can_sleep
, unlock
;
1548 can_sleep
= !(cmd
& LOCK_NB
);
1550 unlock
= (cmd
== LOCK_UN
);
1552 if (!unlock
&& !(cmd
& LOCK_MAND
) && !(filp
->f_mode
& 3))
1555 error
= flock_make_lock(filp
, &lock
, cmd
);
1559 lock
->fl_flags
|= FL_SLEEP
;
1561 error
= security_file_lock(filp
, cmd
);
1565 if (filp
->f_op
&& filp
->f_op
->flock
)
1566 error
= filp
->f_op
->flock(filp
,
1567 (can_sleep
) ? F_SETLKW
: F_SETLK
,
1570 error
= flock_lock_file_wait(filp
, lock
);
1573 locks_free_lock(lock
);
1582 * vfs_test_lock - test file byte range lock
1583 * @filp: The file to test lock for
1584 * @fl: The lock to test
1585 * @conf: Place to return a copy of the conflicting lock, if found
1587 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1588 * setting conf->fl_type to something other than F_UNLCK.
1590 int vfs_test_lock(struct file
*filp
, struct file_lock
*fl
)
1592 if (filp
->f_op
&& filp
->f_op
->lock
)
1593 return filp
->f_op
->lock(filp
, F_GETLK
, fl
);
1594 posix_test_lock(filp
, fl
);
1597 EXPORT_SYMBOL_GPL(vfs_test_lock
);
1599 static int posix_lock_to_flock(struct flock
*flock
, struct file_lock
*fl
)
1601 flock
->l_pid
= fl
->fl_pid
;
1602 #if BITS_PER_LONG == 32
1604 * Make sure we can represent the posix lock via
1605 * legacy 32bit flock.
1607 if (fl
->fl_start
> OFFT_OFFSET_MAX
)
1609 if (fl
->fl_end
!= OFFSET_MAX
&& fl
->fl_end
> OFFT_OFFSET_MAX
)
1612 flock
->l_start
= fl
->fl_start
;
1613 flock
->l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1614 fl
->fl_end
- fl
->fl_start
+ 1;
1615 flock
->l_whence
= 0;
1616 flock
->l_type
= fl
->fl_type
;
1620 #if BITS_PER_LONG == 32
1621 static void posix_lock_to_flock64(struct flock64
*flock
, struct file_lock
*fl
)
1623 flock
->l_pid
= fl
->fl_pid
;
1624 flock
->l_start
= fl
->fl_start
;
1625 flock
->l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1626 fl
->fl_end
- fl
->fl_start
+ 1;
1627 flock
->l_whence
= 0;
1628 flock
->l_type
= fl
->fl_type
;
1632 /* Report the first existing lock that would conflict with l.
1633 * This implements the F_GETLK command of fcntl().
1635 int fcntl_getlk(struct file
*filp
, struct flock __user
*l
)
1637 struct file_lock file_lock
;
1642 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1645 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
1648 error
= flock_to_posix_lock(filp
, &file_lock
, &flock
);
1652 error
= vfs_test_lock(filp
, &file_lock
);
1656 flock
.l_type
= file_lock
.fl_type
;
1657 if (file_lock
.fl_type
!= F_UNLCK
) {
1658 error
= posix_lock_to_flock(&flock
, &file_lock
);
1663 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
1670 * vfs_lock_file - file byte range lock
1671 * @filp: The file to apply the lock to
1672 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
1673 * @fl: The lock to be applied
1674 * @conf: Place to return a copy of the conflicting lock, if found.
1676 * A caller that doesn't care about the conflicting lock may pass NULL
1677 * as the final argument.
1679 * If the filesystem defines a private ->lock() method, then @conf will
1680 * be left unchanged; so a caller that cares should initialize it to
1681 * some acceptable default.
1683 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
1684 * locks, the ->lock() interface may return asynchronously, before the lock has
1685 * been granted or denied by the underlying filesystem, if (and only if)
1686 * fl_grant is set. Callers expecting ->lock() to return asynchronously
1687 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
1688 * the request is for a blocking lock. When ->lock() does return asynchronously,
1689 * it must return -EINPROGRESS, and call ->fl_grant() when the lock
1690 * request completes.
1691 * If the request is for non-blocking lock the file system should return
1692 * -EINPROGRESS then try to get the lock and call the callback routine with
1693 * the result. If the request timed out the callback routine will return a
1694 * nonzero return code and the file system should release the lock. The file
1695 * system is also responsible to keep a corresponding posix lock when it
1696 * grants a lock so the VFS can find out which locks are locally held and do
1697 * the correct lock cleanup when required.
1698 * The underlying filesystem must not drop the kernel lock or call
1699 * ->fl_grant() before returning to the caller with a -EINPROGRESS
1702 int vfs_lock_file(struct file
*filp
, unsigned int cmd
, struct file_lock
*fl
, struct file_lock
*conf
)
1704 if (filp
->f_op
&& filp
->f_op
->lock
)
1705 return filp
->f_op
->lock(filp
, cmd
, fl
);
1707 return posix_lock_file(filp
, fl
, conf
);
1709 EXPORT_SYMBOL_GPL(vfs_lock_file
);
1711 /* Apply the lock described by l to an open file descriptor.
1712 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1714 int fcntl_setlk(unsigned int fd
, struct file
*filp
, unsigned int cmd
,
1715 struct flock __user
*l
)
1717 struct file_lock
*file_lock
= locks_alloc_lock();
1719 struct inode
*inode
;
1722 if (file_lock
== NULL
)
1726 * This might block, so we do it before checking the inode.
1729 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1732 inode
= filp
->f_path
.dentry
->d_inode
;
1734 /* Don't allow mandatory locks on files that may be memory mapped
1737 if (IS_MANDLOCK(inode
) &&
1738 (inode
->i_mode
& (S_ISGID
| S_IXGRP
)) == S_ISGID
&&
1739 mapping_writably_mapped(filp
->f_mapping
)) {
1745 error
= flock_to_posix_lock(filp
, file_lock
, &flock
);
1748 if (cmd
== F_SETLKW
) {
1749 file_lock
->fl_flags
|= FL_SLEEP
;
1753 switch (flock
.l_type
) {
1755 if (!(filp
->f_mode
& FMODE_READ
))
1759 if (!(filp
->f_mode
& FMODE_WRITE
))
1769 error
= security_file_lock(filp
, file_lock
->fl_type
);
1774 error
= vfs_lock_file(filp
, cmd
, file_lock
, NULL
);
1775 if (error
!= -EAGAIN
|| cmd
== F_SETLK
)
1777 error
= wait_event_interruptible(file_lock
->fl_wait
,
1778 !file_lock
->fl_next
);
1782 locks_delete_block(file_lock
);
1787 * Attempt to detect a close/fcntl race and recover by
1788 * releasing the lock that was just acquired.
1790 if (!error
&& fcheck(fd
) != filp
&& flock
.l_type
!= F_UNLCK
) {
1791 flock
.l_type
= F_UNLCK
;
1796 locks_free_lock(file_lock
);
1800 #if BITS_PER_LONG == 32
1801 /* Report the first existing lock that would conflict with l.
1802 * This implements the F_GETLK command of fcntl().
1804 int fcntl_getlk64(struct file
*filp
, struct flock64 __user
*l
)
1806 struct file_lock file_lock
;
1807 struct flock64 flock
;
1811 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1814 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
1817 error
= flock64_to_posix_lock(filp
, &file_lock
, &flock
);
1821 error
= vfs_test_lock(filp
, &file_lock
);
1825 flock
.l_type
= file_lock
.fl_type
;
1826 if (file_lock
.fl_type
!= F_UNLCK
)
1827 posix_lock_to_flock64(&flock
, &file_lock
);
1830 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
1837 /* Apply the lock described by l to an open file descriptor.
1838 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1840 int fcntl_setlk64(unsigned int fd
, struct file
*filp
, unsigned int cmd
,
1841 struct flock64 __user
*l
)
1843 struct file_lock
*file_lock
= locks_alloc_lock();
1844 struct flock64 flock
;
1845 struct inode
*inode
;
1848 if (file_lock
== NULL
)
1852 * This might block, so we do it before checking the inode.
1855 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1858 inode
= filp
->f_path
.dentry
->d_inode
;
1860 /* Don't allow mandatory locks on files that may be memory mapped
1863 if (IS_MANDLOCK(inode
) &&
1864 (inode
->i_mode
& (S_ISGID
| S_IXGRP
)) == S_ISGID
&&
1865 mapping_writably_mapped(filp
->f_mapping
)) {
1871 error
= flock64_to_posix_lock(filp
, file_lock
, &flock
);
1874 if (cmd
== F_SETLKW64
) {
1875 file_lock
->fl_flags
|= FL_SLEEP
;
1879 switch (flock
.l_type
) {
1881 if (!(filp
->f_mode
& FMODE_READ
))
1885 if (!(filp
->f_mode
& FMODE_WRITE
))
1895 error
= security_file_lock(filp
, file_lock
->fl_type
);
1900 error
= vfs_lock_file(filp
, cmd
, file_lock
, NULL
);
1901 if (error
!= -EAGAIN
|| cmd
== F_SETLK64
)
1903 error
= wait_event_interruptible(file_lock
->fl_wait
,
1904 !file_lock
->fl_next
);
1908 locks_delete_block(file_lock
);
1913 * Attempt to detect a close/fcntl race and recover by
1914 * releasing the lock that was just acquired.
1916 if (!error
&& fcheck(fd
) != filp
&& flock
.l_type
!= F_UNLCK
) {
1917 flock
.l_type
= F_UNLCK
;
1922 locks_free_lock(file_lock
);
1925 #endif /* BITS_PER_LONG == 32 */
1928 * This function is called when the file is being removed
1929 * from the task's fd array. POSIX locks belonging to this task
1930 * are deleted at this time.
1932 void locks_remove_posix(struct file
*filp
, fl_owner_t owner
)
1934 struct file_lock lock
;
1937 * If there are no locks held on this file, we don't need to call
1938 * posix_lock_file(). Another process could be setting a lock on this
1939 * file at the same time, but we wouldn't remove that lock anyway.
1941 if (!filp
->f_path
.dentry
->d_inode
->i_flock
)
1944 lock
.fl_type
= F_UNLCK
;
1945 lock
.fl_flags
= FL_POSIX
| FL_CLOSE
;
1947 lock
.fl_end
= OFFSET_MAX
;
1948 lock
.fl_owner
= owner
;
1949 lock
.fl_pid
= current
->tgid
;
1950 lock
.fl_file
= filp
;
1952 lock
.fl_lmops
= NULL
;
1954 vfs_lock_file(filp
, F_SETLK
, &lock
, NULL
);
1956 if (lock
.fl_ops
&& lock
.fl_ops
->fl_release_private
)
1957 lock
.fl_ops
->fl_release_private(&lock
);
1960 EXPORT_SYMBOL(locks_remove_posix
);
1963 * This function is called on the last close of an open file.
1965 void locks_remove_flock(struct file
*filp
)
1967 struct inode
* inode
= filp
->f_path
.dentry
->d_inode
;
1968 struct file_lock
*fl
;
1969 struct file_lock
**before
;
1971 if (!inode
->i_flock
)
1974 if (filp
->f_op
&& filp
->f_op
->flock
) {
1975 struct file_lock fl
= {
1976 .fl_pid
= current
->tgid
,
1978 .fl_flags
= FL_FLOCK
,
1980 .fl_end
= OFFSET_MAX
,
1982 filp
->f_op
->flock(filp
, F_SETLKW
, &fl
);
1983 if (fl
.fl_ops
&& fl
.fl_ops
->fl_release_private
)
1984 fl
.fl_ops
->fl_release_private(&fl
);
1988 before
= &inode
->i_flock
;
1990 while ((fl
= *before
) != NULL
) {
1991 if (fl
->fl_file
== filp
) {
1993 locks_delete_lock(before
);
1997 lease_modify(before
, F_UNLCK
);
2003 before
= &fl
->fl_next
;
2009 * posix_unblock_lock - stop waiting for a file lock
2010 * @filp: how the file was opened
2011 * @waiter: the lock which was waiting
2013 * lockd needs to block waiting for locks.
2016 posix_unblock_lock(struct file
*filp
, struct file_lock
*waiter
)
2021 if (waiter
->fl_next
)
2022 __locks_delete_block(waiter
);
2029 EXPORT_SYMBOL(posix_unblock_lock
);
2032 * vfs_cancel_lock - file byte range unblock lock
2033 * @filp: The file to apply the unblock to
2034 * @fl: The lock to be unblocked
2036 * Used by lock managers to cancel blocked requests
2038 int vfs_cancel_lock(struct file
*filp
, struct file_lock
*fl
)
2040 if (filp
->f_op
&& filp
->f_op
->lock
)
2041 return filp
->f_op
->lock(filp
, F_CANCELLK
, fl
);
2045 EXPORT_SYMBOL_GPL(vfs_cancel_lock
);
2047 static void lock_get_status(char* out
, struct file_lock
*fl
, int id
, char *pfx
)
2049 struct inode
*inode
= NULL
;
2051 if (fl
->fl_file
!= NULL
)
2052 inode
= fl
->fl_file
->f_path
.dentry
->d_inode
;
2054 out
+= sprintf(out
, "%d:%s ", id
, pfx
);
2056 out
+= sprintf(out
, "%6s %s ",
2057 (fl
->fl_flags
& FL_ACCESS
) ? "ACCESS" : "POSIX ",
2058 (inode
== NULL
) ? "*NOINODE*" :
2059 (IS_MANDLOCK(inode
) &&
2060 (inode
->i_mode
& (S_IXGRP
| S_ISGID
)) == S_ISGID
) ?
2061 "MANDATORY" : "ADVISORY ");
2062 } else if (IS_FLOCK(fl
)) {
2063 if (fl
->fl_type
& LOCK_MAND
) {
2064 out
+= sprintf(out
, "FLOCK MSNFS ");
2066 out
+= sprintf(out
, "FLOCK ADVISORY ");
2068 } else if (IS_LEASE(fl
)) {
2069 out
+= sprintf(out
, "LEASE ");
2070 if (fl
->fl_type
& F_INPROGRESS
)
2071 out
+= sprintf(out
, "BREAKING ");
2072 else if (fl
->fl_file
)
2073 out
+= sprintf(out
, "ACTIVE ");
2075 out
+= sprintf(out
, "BREAKER ");
2077 out
+= sprintf(out
, "UNKNOWN UNKNOWN ");
2079 if (fl
->fl_type
& LOCK_MAND
) {
2080 out
+= sprintf(out
, "%s ",
2081 (fl
->fl_type
& LOCK_READ
)
2082 ? (fl
->fl_type
& LOCK_WRITE
) ? "RW " : "READ "
2083 : (fl
->fl_type
& LOCK_WRITE
) ? "WRITE" : "NONE ");
2085 out
+= sprintf(out
, "%s ",
2086 (fl
->fl_type
& F_INPROGRESS
)
2087 ? (fl
->fl_type
& F_UNLCK
) ? "UNLCK" : "READ "
2088 : (fl
->fl_type
& F_WRLCK
) ? "WRITE" : "READ ");
2091 #ifdef WE_CAN_BREAK_LSLK_NOW
2092 out
+= sprintf(out
, "%d %s:%ld ", fl
->fl_pid
,
2093 inode
->i_sb
->s_id
, inode
->i_ino
);
2095 /* userspace relies on this representation of dev_t ;-( */
2096 out
+= sprintf(out
, "%d %02x:%02x:%ld ", fl
->fl_pid
,
2097 MAJOR(inode
->i_sb
->s_dev
),
2098 MINOR(inode
->i_sb
->s_dev
), inode
->i_ino
);
2101 out
+= sprintf(out
, "%d <none>:0 ", fl
->fl_pid
);
2104 if (fl
->fl_end
== OFFSET_MAX
)
2105 out
+= sprintf(out
, "%Ld EOF\n", fl
->fl_start
);
2107 out
+= sprintf(out
, "%Ld %Ld\n", fl
->fl_start
,
2110 out
+= sprintf(out
, "0 EOF\n");
2114 static void move_lock_status(char **p
, off_t
* pos
, off_t offset
)
2118 if(*pos
>= offset
) {
2119 /* the complete line is valid */
2124 if(*pos
+len
> offset
) {
2125 /* use the second part of the line */
2126 int i
= offset
-*pos
;
2127 memmove(*p
,*p
+i
,len
-i
);
2132 /* discard the complete line */
2137 * get_locks_status - reports lock usage in /proc/locks
2138 * @buffer: address in userspace to write into
2140 * @offset: how far we are through the buffer
2141 * @length: how much to read
2144 int get_locks_status(char *buffer
, char **start
, off_t offset
, int length
)
2146 struct list_head
*tmp
;
2152 list_for_each(tmp
, &file_lock_list
) {
2153 struct list_head
*btmp
;
2154 struct file_lock
*fl
= list_entry(tmp
, struct file_lock
, fl_link
);
2155 lock_get_status(q
, fl
, ++i
, "");
2156 move_lock_status(&q
, &pos
, offset
);
2158 if(pos
>= offset
+length
)
2161 list_for_each(btmp
, &fl
->fl_block
) {
2162 struct file_lock
*bfl
= list_entry(btmp
,
2163 struct file_lock
, fl_block
);
2164 lock_get_status(q
, bfl
, i
, " ->");
2165 move_lock_status(&q
, &pos
, offset
);
2167 if(pos
>= offset
+length
)
2174 if(q
-buffer
< length
)
2180 * lock_may_read - checks that the region is free of locks
2181 * @inode: the inode that is being read
2182 * @start: the first byte to read
2183 * @len: the number of bytes to read
2185 * Emulates Windows locking requirements. Whole-file
2186 * mandatory locks (share modes) can prohibit a read and
2187 * byte-range POSIX locks can prohibit a read if they overlap.
2189 * N.B. this function is only ever called
2190 * from knfsd and ownership of locks is never checked.
2192 int lock_may_read(struct inode
*inode
, loff_t start
, unsigned long len
)
2194 struct file_lock
*fl
;
2197 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
2199 if (fl
->fl_type
== F_RDLCK
)
2201 if ((fl
->fl_end
< start
) || (fl
->fl_start
> (start
+ len
)))
2203 } else if (IS_FLOCK(fl
)) {
2204 if (!(fl
->fl_type
& LOCK_MAND
))
2206 if (fl
->fl_type
& LOCK_READ
)
2217 EXPORT_SYMBOL(lock_may_read
);
2220 * lock_may_write - checks that the region is free of locks
2221 * @inode: the inode that is being written
2222 * @start: the first byte to write
2223 * @len: the number of bytes to write
2225 * Emulates Windows locking requirements. Whole-file
2226 * mandatory locks (share modes) can prohibit a write and
2227 * byte-range POSIX locks can prohibit a write if they overlap.
2229 * N.B. this function is only ever called
2230 * from knfsd and ownership of locks is never checked.
2232 int lock_may_write(struct inode
*inode
, loff_t start
, unsigned long len
)
2234 struct file_lock
*fl
;
2237 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
2239 if ((fl
->fl_end
< start
) || (fl
->fl_start
> (start
+ len
)))
2241 } else if (IS_FLOCK(fl
)) {
2242 if (!(fl
->fl_type
& LOCK_MAND
))
2244 if (fl
->fl_type
& LOCK_WRITE
)
2255 EXPORT_SYMBOL(lock_may_write
);
2257 static int __init
filelock_init(void)
2259 filelock_cache
= kmem_cache_create("file_lock_cache",
2260 sizeof(struct file_lock
), 0, SLAB_PANIC
,
2265 core_initcall(filelock_init
);