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 'linux/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@thepuffingroup.com>, March, 2000.
112 * Leases and LOCK_MAND
113 * Matthew Wilcox <willy@linuxcare.com>, June, 2000.
114 * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
117 #include <linux/slab.h>
118 #include <linux/file.h>
119 #include <linux/smp_lock.h>
120 #include <linux/init.h>
121 #include <linux/capability.h>
122 #include <linux/timer.h>
123 #include <linux/time.h>
124 #include <linux/fs.h>
126 #include <asm/semaphore.h>
127 #include <asm/uaccess.h>
129 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
130 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
131 #define IS_LEASE(fl) (fl->fl_flags & FL_LEASE)
133 int leases_enable
= 1;
134 int lease_break_time
= 45;
136 #define for_each_lock(inode, lockp) \
137 for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
139 LIST_HEAD(file_lock_list
);
140 static LIST_HEAD(blocked_list
);
142 static kmem_cache_t
*filelock_cache
;
144 /* Allocate an empty lock structure. */
145 static struct file_lock
*locks_alloc_lock(int account
)
147 struct file_lock
*fl
;
148 if (account
&& current
->locks
>= current
->rlim
[RLIMIT_LOCKS
].rlim_cur
)
150 fl
= kmem_cache_alloc(filelock_cache
, SLAB_KERNEL
);
156 /* Free a lock which is not in use. */
157 static inline void locks_free_lock(struct file_lock
*fl
)
164 if (waitqueue_active(&fl
->fl_wait
))
165 panic("Attempting to free lock with active wait queue");
167 if (!list_empty(&fl
->fl_block
))
168 panic("Attempting to free lock with active block list");
170 if (!list_empty(&fl
->fl_link
))
171 panic("Attempting to free lock on active lock list");
173 kmem_cache_free(filelock_cache
, fl
);
176 void locks_init_lock(struct file_lock
*fl
)
178 INIT_LIST_HEAD(&fl
->fl_link
);
179 INIT_LIST_HEAD(&fl
->fl_block
);
180 init_waitqueue_head(&fl
->fl_wait
);
182 fl
->fl_fasync
= NULL
;
188 fl
->fl_start
= fl
->fl_end
= 0;
189 fl
->fl_notify
= NULL
;
190 fl
->fl_insert
= NULL
;
191 fl
->fl_remove
= NULL
;
195 * Initialises the fields of the file lock which are invariant for
198 static void init_once(void *foo
, kmem_cache_t
*cache
, unsigned long flags
)
200 struct file_lock
*lock
= (struct file_lock
*) foo
;
202 if ((flags
& (SLAB_CTOR_VERIFY
|SLAB_CTOR_CONSTRUCTOR
)) !=
203 SLAB_CTOR_CONSTRUCTOR
)
206 locks_init_lock(lock
);
210 * Initialize a new lock from an existing file_lock structure.
212 void locks_copy_lock(struct file_lock
*new, struct file_lock
*fl
)
214 new->fl_owner
= fl
->fl_owner
;
215 new->fl_pid
= fl
->fl_pid
;
216 new->fl_file
= fl
->fl_file
;
217 new->fl_flags
= fl
->fl_flags
;
218 new->fl_type
= fl
->fl_type
;
219 new->fl_start
= fl
->fl_start
;
220 new->fl_end
= fl
->fl_end
;
221 new->fl_notify
= fl
->fl_notify
;
222 new->fl_insert
= fl
->fl_insert
;
223 new->fl_remove
= fl
->fl_remove
;
224 new->fl_u
= fl
->fl_u
;
227 static inline int flock_translate_cmd(int cmd
) {
229 return cmd
& (LOCK_MAND
| LOCK_RW
);
230 switch (cmd
&~ LOCK_NB
) {
241 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
242 static int flock_make_lock(struct file
*filp
,
243 struct file_lock
**lock
, unsigned int cmd
)
245 struct file_lock
*fl
;
246 int type
= flock_translate_cmd(cmd
);
250 fl
= locks_alloc_lock(1);
255 fl
->fl_pid
= current
->tgid
;
256 fl
->fl_flags
= (cmd
& LOCK_NB
) ? FL_FLOCK
: FL_FLOCK
| FL_SLEEP
;
258 fl
->fl_end
= OFFSET_MAX
;
264 static int assign_type(struct file_lock
*fl
, int type
)
278 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
281 static int flock_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
286 switch (l
->l_whence
) {
294 start
= filp
->f_dentry
->d_inode
->i_size
;
300 if (((start
+= l
->l_start
) < 0) || (l
->l_len
< 0))
302 end
= start
+ l
->l_len
- 1;
303 if (l
->l_len
> 0 && end
< 0)
305 fl
->fl_start
= start
; /* we record the absolute position */
308 fl
->fl_end
= OFFSET_MAX
;
310 fl
->fl_owner
= current
->files
;
311 fl
->fl_pid
= current
->tgid
;
313 fl
->fl_flags
= FL_POSIX
;
314 fl
->fl_notify
= NULL
;
315 fl
->fl_insert
= NULL
;
316 fl
->fl_remove
= NULL
;
318 return assign_type(fl
, l
->l_type
);
321 #if BITS_PER_LONG == 32
322 static int flock64_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
327 switch (l
->l_whence
) {
335 start
= filp
->f_dentry
->d_inode
->i_size
;
341 if (((start
+= l
->l_start
) < 0) || (l
->l_len
< 0))
343 fl
->fl_end
= start
+ l
->l_len
- 1;
344 if (l
->l_len
> 0 && fl
->fl_end
< 0)
346 fl
->fl_start
= start
; /* we record the absolute position */
348 fl
->fl_end
= OFFSET_MAX
;
350 fl
->fl_owner
= current
->files
;
351 fl
->fl_pid
= current
->tgid
;
353 fl
->fl_flags
= FL_POSIX
;
354 fl
->fl_notify
= NULL
;
355 fl
->fl_insert
= NULL
;
356 fl
->fl_remove
= NULL
;
362 fl
->fl_type
= l
->l_type
;
372 /* Allocate a file_lock initialised to this type of lease */
373 static int lease_alloc(struct file
*filp
, int type
, struct file_lock
**flp
)
375 struct file_lock
*fl
= locks_alloc_lock(1);
379 fl
->fl_owner
= current
->files
;
380 fl
->fl_pid
= current
->tgid
;
383 fl
->fl_flags
= FL_LEASE
;
384 if (assign_type(fl
, type
) != 0) {
389 fl
->fl_end
= OFFSET_MAX
;
390 fl
->fl_notify
= NULL
;
391 fl
->fl_insert
= NULL
;
392 fl
->fl_remove
= NULL
;
398 /* Check if two locks overlap each other.
400 static inline int locks_overlap(struct file_lock
*fl1
, struct file_lock
*fl2
)
402 return ((fl1
->fl_end
>= fl2
->fl_start
) &&
403 (fl2
->fl_end
>= fl1
->fl_start
));
407 * Check whether two locks have the same owner. The apparently superfluous
408 * check for fl_pid enables us to distinguish between locks set by lockd.
411 posix_same_owner(struct file_lock
*fl1
, struct file_lock
*fl2
)
413 return (fl1
->fl_owner
== fl2
->fl_owner
) &&
414 (fl1
->fl_pid
== fl2
->fl_pid
);
417 /* Remove waiter from blocker's block list.
418 * When blocker ends up pointing to itself then the list is empty.
420 static void locks_delete_block(struct file_lock
*waiter
)
422 list_del_init(&waiter
->fl_block
);
423 list_del_init(&waiter
->fl_link
);
424 waiter
->fl_next
= NULL
;
427 /* Insert waiter into blocker's block list.
428 * We use a circular list so that processes can be easily woken up in
429 * the order they blocked. The documentation doesn't require this but
430 * it seems like the reasonable thing to do.
432 static void locks_insert_block(struct file_lock
*blocker
,
433 struct file_lock
*waiter
)
435 if (!list_empty(&waiter
->fl_block
)) {
436 printk(KERN_ERR
"locks_insert_block: removing duplicated lock "
437 "(pid=%d %Ld-%Ld type=%d)\n", waiter
->fl_pid
,
438 waiter
->fl_start
, waiter
->fl_end
, waiter
->fl_type
);
439 locks_delete_block(waiter
);
441 list_add_tail(&waiter
->fl_block
, &blocker
->fl_block
);
442 waiter
->fl_next
= blocker
;
443 list_add(&waiter
->fl_link
, &blocked_list
);
446 /* Wake up processes blocked waiting for blocker.
447 * If told to wait then schedule the processes until the block list
448 * is empty, otherwise empty the block list ourselves.
450 static void locks_wake_up_blocks(struct file_lock
*blocker
)
452 while (!list_empty(&blocker
->fl_block
)) {
453 struct file_lock
*waiter
= list_entry(blocker
->fl_block
.next
,
454 struct file_lock
, fl_block
);
455 locks_delete_block(waiter
);
456 if (waiter
->fl_notify
)
457 waiter
->fl_notify(waiter
);
459 wake_up(&waiter
->fl_wait
);
463 /* Insert file lock fl into an inode's lock list at the position indicated
464 * by pos. At the same time add the lock to the global file lock list.
466 static void locks_insert_lock(struct file_lock
**pos
, struct file_lock
*fl
)
468 list_add(&fl
->fl_link
, &file_lock_list
);
470 /* insert into file's list */
479 * Delete a lock and then free it.
480 * Wake up processes that are blocked waiting for this lock,
481 * notify the FS that the lock has been cleared and
482 * finally free the lock.
484 static void locks_delete_lock(struct file_lock
**thisfl_p
)
486 struct file_lock
*fl
= *thisfl_p
;
488 *thisfl_p
= fl
->fl_next
;
490 list_del_init(&fl
->fl_link
);
492 fasync_helper(0, fl
->fl_file
, 0, &fl
->fl_fasync
);
493 if (fl
->fl_fasync
!= NULL
) {
494 printk(KERN_ERR
"locks_delete_lock: fasync == %p\n", fl
->fl_fasync
);
495 fl
->fl_fasync
= NULL
;
501 locks_wake_up_blocks(fl
);
505 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
506 * checks for shared/exclusive status of overlapping locks.
508 static int locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
510 switch (caller_fl
->fl_type
) {
512 return (sys_fl
->fl_type
== F_WRLCK
);
518 printk(KERN_ERR
"locks_conflict(): impossible lock type - %d\n",
522 return (0); /* This should never happen */
525 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
526 * checking before calling the locks_conflict().
528 static int posix_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
530 /* POSIX locks owned by the same process do not conflict with
533 if (!IS_POSIX(sys_fl
) || posix_same_owner(caller_fl
, sys_fl
))
536 /* Check whether they overlap */
537 if (!locks_overlap(caller_fl
, sys_fl
))
540 return (locks_conflict(caller_fl
, sys_fl
));
543 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
544 * checking before calling the locks_conflict().
546 static int flock_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
548 /* FLOCK locks referring to the same filp do not conflict with
551 if (!IS_FLOCK(sys_fl
) || (caller_fl
->fl_file
== sys_fl
->fl_file
))
553 if ((caller_fl
->fl_type
& LOCK_MAND
) || (sys_fl
->fl_type
& LOCK_MAND
))
556 return (locks_conflict(caller_fl
, sys_fl
));
559 static int interruptible_sleep_on_locked(wait_queue_head_t
*fl_wait
, int timeout
)
562 DECLARE_WAITQUEUE(wait
, current
);
564 current
->state
= TASK_INTERRUPTIBLE
;
565 add_wait_queue(fl_wait
, &wait
);
569 result
= schedule_timeout(timeout
);
570 if (signal_pending(current
))
571 result
= -ERESTARTSYS
;
572 remove_wait_queue(fl_wait
, &wait
);
573 current
->state
= TASK_RUNNING
;
577 static int locks_block_on_timeout(struct file_lock
*blocker
, struct file_lock
*waiter
, int time
)
580 locks_insert_block(blocker
, waiter
);
581 result
= interruptible_sleep_on_locked(&waiter
->fl_wait
, time
);
582 locks_delete_block(waiter
);
587 posix_test_lock(struct file
*filp
, struct file_lock
*fl
)
589 struct file_lock
*cfl
;
592 for (cfl
= filp
->f_dentry
->d_inode
->i_flock
; cfl
; cfl
= cfl
->fl_next
) {
595 if (posix_locks_conflict(cfl
, fl
))
603 /* This function tests for deadlock condition before putting a process to
604 * sleep. The detection scheme is no longer recursive. Recursive was neat,
605 * but dangerous - we risked stack corruption if the lock data was bad, or
606 * if the recursion was too deep for any other reason.
608 * We rely on the fact that a task can only be on one lock's wait queue
609 * at a time. When we find blocked_task on a wait queue we can re-search
610 * with blocked_task equal to that queue's owner, until either blocked_task
611 * isn't found, or blocked_task is found on a queue owned by my_task.
613 * Note: the above assumption may not be true when handling lock requests
614 * from a broken NFS client. But broken NFS clients have a lot more to
615 * worry about than proper deadlock detection anyway... --okir
617 int posix_locks_deadlock(struct file_lock
*caller_fl
,
618 struct file_lock
*block_fl
)
620 struct list_head
*tmp
;
621 fl_owner_t caller_owner
, blocked_owner
;
622 unsigned int caller_pid
, blocked_pid
;
624 caller_owner
= caller_fl
->fl_owner
;
625 caller_pid
= caller_fl
->fl_pid
;
626 blocked_owner
= block_fl
->fl_owner
;
627 blocked_pid
= block_fl
->fl_pid
;
630 if (caller_owner
== blocked_owner
&& caller_pid
== blocked_pid
)
632 list_for_each(tmp
, &blocked_list
) {
633 struct file_lock
*fl
= list_entry(tmp
, struct file_lock
, fl_link
);
634 if ((fl
->fl_owner
== blocked_owner
)
635 && (fl
->fl_pid
== blocked_pid
)) {
637 blocked_owner
= fl
->fl_owner
;
638 blocked_pid
= fl
->fl_pid
;
645 int locks_mandatory_locked(struct inode
*inode
)
647 fl_owner_t owner
= current
->files
;
648 struct file_lock
*fl
;
651 * Search the lock list for this inode for any POSIX locks.
654 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
657 if (fl
->fl_owner
!= owner
)
661 return fl
? -EAGAIN
: 0;
664 int locks_mandatory_area(int read_write
, struct inode
*inode
,
665 struct file
*filp
, loff_t offset
,
671 fl
.fl_owner
= current
->files
;
672 fl
.fl_pid
= current
->tgid
;
674 fl
.fl_flags
= FL_POSIX
| FL_ACCESS
| FL_SLEEP
;
675 fl
.fl_type
= (read_write
== FLOCK_VERIFY_WRITE
) ? F_WRLCK
: F_RDLCK
;
676 fl
.fl_start
= offset
;
677 fl
.fl_end
= offset
+ count
- 1;
680 error
= posix_lock_file(filp
, &fl
);
681 if (error
!= -EAGAIN
)
683 error
= wait_event_interruptible(fl
.fl_wait
, !fl
.fl_next
);
686 * If we've been sleeping someone might have
687 * changed the permissions behind our back.
689 if ((inode
->i_mode
& (S_ISGID
| S_IXGRP
)) == S_ISGID
)
694 locks_delete_block(&fl
);
702 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
703 * at the head of the list, but that's secret knowledge known only to
704 * flock_lock_file and posix_lock_file.
706 static int flock_lock_file(struct file
*filp
, struct file_lock
*new_fl
)
708 struct file_lock
**before
;
709 struct inode
* inode
= filp
->f_dentry
->d_inode
;
714 for_each_lock(inode
, before
) {
715 struct file_lock
*fl
= *before
;
720 if (filp
!= fl
->fl_file
)
722 if (new_fl
->fl_type
== fl
->fl_type
)
725 locks_delete_lock(before
);
730 if (new_fl
->fl_type
== F_UNLCK
)
734 * If a higher-priority process was blocked on the old file lock,
735 * give it the opportunity to lock the file.
741 for_each_lock(inode
, before
) {
742 struct file_lock
*fl
= *before
;
747 if (!flock_locks_conflict(new_fl
, fl
))
750 if (new_fl
->fl_flags
& FL_SLEEP
) {
751 locks_insert_block(fl
, new_fl
);
755 locks_insert_lock(&inode
->i_flock
, new_fl
);
765 * @filp: The file to apply the lock to
766 * @caller: The lock to be applied
767 * @wait: 1 to retry automatically, 0 to return -EAGAIN
769 * Add a POSIX style lock to a file.
770 * We merge adjacent locks whenever possible. POSIX locks are sorted by owner
771 * task, then by starting address
774 * To make freeing a lock much faster, we keep a pointer to the lock before the
775 * actual one. But the real gain of the new coding was, that lock_it() and
776 * unlock_it() became one function.
778 * To all purists: Yes, I use a few goto's. Just pass on to the next function.
781 int posix_lock_file(struct file
*filp
, struct file_lock
*request
)
783 struct file_lock
*fl
;
784 struct file_lock
*new_fl
, *new_fl2
;
785 struct file_lock
*left
= NULL
;
786 struct file_lock
*right
= NULL
;
787 struct file_lock
**before
;
788 struct inode
* inode
= filp
->f_dentry
->d_inode
;
789 int error
, added
= 0;
792 * We may need two file_lock structures for this operation,
793 * so we get them in advance to avoid races.
795 new_fl
= locks_alloc_lock(0);
796 new_fl2
= locks_alloc_lock(0);
797 error
= -ENOLCK
; /* "no luck" */
798 if (!(new_fl
&& new_fl2
))
802 if (request
->fl_type
!= F_UNLCK
) {
803 for_each_lock(inode
, before
) {
804 struct file_lock
*fl
= *before
;
807 if (!posix_locks_conflict(request
, fl
))
810 if (!(request
->fl_flags
& FL_SLEEP
))
813 if (posix_locks_deadlock(request
, fl
))
816 locks_insert_block(fl
, request
);
821 /* If we're just looking for a conflict, we're done. */
822 if (request
->fl_flags
& FL_ACCESS
)
826 * We've allocated the new locks in advance, so there are no
827 * errors possible (and no blocking operations) from here on.
829 * Find the first old lock with the same owner as the new lock.
832 before
= &inode
->i_flock
;
834 /* First skip locks owned by other processes. */
835 while ((fl
= *before
) && (!IS_POSIX(fl
) ||
836 !posix_same_owner(request
, fl
))) {
837 before
= &fl
->fl_next
;
840 /* Process locks with this owner. */
841 while ((fl
= *before
) && posix_same_owner(request
, fl
)) {
842 /* Detect adjacent or overlapping regions (if same lock type)
844 if (request
->fl_type
== fl
->fl_type
) {
845 if (fl
->fl_end
< request
->fl_start
- 1)
847 /* If the next lock in the list has entirely bigger
848 * addresses than the new one, insert the lock here.
850 if (fl
->fl_start
> request
->fl_end
+ 1)
853 /* If we come here, the new and old lock are of the
854 * same type and adjacent or overlapping. Make one
855 * lock yielding from the lower start address of both
856 * locks to the higher end address.
858 if (fl
->fl_start
> request
->fl_start
)
859 fl
->fl_start
= request
->fl_start
;
861 request
->fl_start
= fl
->fl_start
;
862 if (fl
->fl_end
< request
->fl_end
)
863 fl
->fl_end
= request
->fl_end
;
865 request
->fl_end
= fl
->fl_end
;
867 locks_delete_lock(before
);
874 /* Processing for different lock types is a bit
877 if (fl
->fl_end
< request
->fl_start
)
879 if (fl
->fl_start
> request
->fl_end
)
881 if (request
->fl_type
== F_UNLCK
)
883 if (fl
->fl_start
< request
->fl_start
)
885 /* If the next lock in the list has a higher end
886 * address than the new one, insert the new one here.
888 if (fl
->fl_end
> request
->fl_end
) {
892 if (fl
->fl_start
>= request
->fl_start
) {
893 /* The new lock completely replaces an old
894 * one (This may happen several times).
897 locks_delete_lock(before
);
900 /* Replace the old lock with the new one.
901 * Wake up anybody waiting for the old one,
902 * as the change in lock type might satisfy
905 locks_wake_up_blocks(fl
);
906 fl
->fl_start
= request
->fl_start
;
907 fl
->fl_end
= request
->fl_end
;
908 fl
->fl_type
= request
->fl_type
;
909 fl
->fl_u
= request
->fl_u
;
914 /* Go on to next lock.
917 before
= &fl
->fl_next
;
922 if (request
->fl_type
== F_UNLCK
)
924 locks_copy_lock(new_fl
, request
);
925 locks_insert_lock(before
, new_fl
);
930 /* The new lock breaks the old one in two pieces,
931 * so we have to use the second new lock.
935 locks_copy_lock(left
, right
);
936 locks_insert_lock(before
, left
);
938 right
->fl_start
= request
->fl_end
+ 1;
939 locks_wake_up_blocks(right
);
942 left
->fl_end
= request
->fl_start
- 1;
943 locks_wake_up_blocks(left
);
949 * Free any unused locks.
952 locks_free_lock(new_fl
);
954 locks_free_lock(new_fl2
);
958 /* We already had a lease on this file; just change its type */
959 static int lease_modify(struct file_lock
**before
, int arg
)
961 struct file_lock
*fl
= *before
;
962 int error
= assign_type(fl
, arg
);
966 locks_wake_up_blocks(fl
);
967 if (arg
== F_UNLCK
) {
968 struct file
*filp
= fl
->fl_file
;
971 filp
->f_owner
.signum
= 0;
972 locks_delete_lock(before
);
977 static void time_out_leases(struct inode
*inode
)
979 struct file_lock
**before
;
980 struct file_lock
*fl
;
982 before
= &inode
->i_flock
;
983 while ((fl
= *before
) && IS_LEASE(fl
) && (fl
->fl_type
& F_INPROGRESS
)) {
984 if ((fl
->fl_break_time
== 0)
985 || time_before(jiffies
, fl
->fl_break_time
)) {
986 before
= &fl
->fl_next
;
989 printk(KERN_INFO
"lease broken - owner pid = %d\n", fl
->fl_pid
);
990 lease_modify(before
, fl
->fl_type
& ~F_INPROGRESS
);
991 if (fl
== *before
) /* lease_modify may have freed fl */
992 before
= &fl
->fl_next
;
997 * __get_lease - revoke all outstanding leases on file
998 * @inode: the inode of the file to return
999 * @mode: the open mode (read or write)
1001 * get_lease (inlined for speed) has checked there already
1002 * is a lease on this file. Leases are broken on a call to open()
1003 * or truncate(). This function can sleep unless you
1004 * specified %O_NONBLOCK to your open().
1006 int __get_lease(struct inode
*inode
, unsigned int mode
)
1008 int error
= 0, future
;
1009 struct file_lock
*new_fl
, *flock
;
1010 struct file_lock
*fl
;
1012 unsigned long break_time
;
1013 int i_have_this_lease
= 0;
1015 alloc_err
= lease_alloc(NULL
, mode
& FMODE_WRITE
? F_WRLCK
: F_RDLCK
,
1020 time_out_leases(inode
);
1022 flock
= inode
->i_flock
;
1023 if ((flock
== NULL
) || !IS_LEASE(flock
))
1026 for (fl
= flock
; fl
&& IS_LEASE(fl
); fl
= fl
->fl_next
)
1027 if (fl
->fl_owner
== current
->files
)
1028 i_have_this_lease
= 1;
1030 if (mode
& FMODE_WRITE
) {
1031 /* If we want write access, we have to revoke any lease. */
1032 future
= F_UNLCK
| F_INPROGRESS
;
1033 } else if (flock
->fl_type
& F_INPROGRESS
) {
1034 /* If the lease is already being broken, we just leave it */
1035 future
= flock
->fl_type
;
1036 } else if (flock
->fl_type
& F_WRLCK
) {
1037 /* Downgrade the exclusive lease to a read-only lease. */
1038 future
= F_RDLCK
| F_INPROGRESS
;
1040 /* the existing lease was read-only, so we can read too. */
1044 if (alloc_err
&& !i_have_this_lease
&& ((mode
& O_NONBLOCK
) == 0)) {
1050 if (lease_break_time
> 0) {
1051 break_time
= jiffies
+ lease_break_time
* HZ
;
1052 if (break_time
== 0)
1053 break_time
++; /* so that 0 means no break time */
1056 for (fl
= flock
; fl
&& IS_LEASE(fl
); fl
= fl
->fl_next
) {
1057 if (fl
->fl_type
!= future
) {
1058 fl
->fl_type
= future
;
1059 fl
->fl_break_time
= break_time
;
1060 kill_fasync(&fl
->fl_fasync
, SIGIO
, POLL_MSG
);
1064 if (i_have_this_lease
|| (mode
& O_NONBLOCK
)) {
1065 error
= -EWOULDBLOCK
;
1070 break_time
= flock
->fl_break_time
;
1071 if (break_time
!= 0) {
1072 break_time
-= jiffies
;
1073 if (break_time
== 0)
1076 error
= locks_block_on_timeout(flock
, new_fl
, break_time
);
1079 time_out_leases(inode
);
1080 /* Wait for the next lease that has not been broken yet */
1081 for (flock
= inode
->i_flock
; flock
&& IS_LEASE(flock
);
1082 flock
= flock
->fl_next
) {
1083 if (flock
->fl_type
& F_INPROGRESS
)
1092 locks_free_lock(new_fl
);
1100 * This is to force NFS clients to flush their caches for files with
1101 * exclusive leases. The justification is that if someone has an
1102 * exclusive lease, then they could be modifiying it.
1104 time_t lease_get_mtime(struct inode
*inode
)
1106 struct file_lock
*flock
= inode
->i_flock
;
1107 if (flock
&& IS_LEASE(flock
) && (flock
->fl_type
& F_WRLCK
))
1108 return CURRENT_TIME
;
1109 return inode
->i_mtime
;
1113 * fcntl_getlease - Enquire what lease is currently active
1116 * The value returned by this function will be one of
1117 * (if no lease break is pending):
1119 * %F_RDLCK to indicate a shared lease is held.
1121 * %F_WRLCK to indicate an exclusive lease is held.
1123 * %F_UNLCK to indicate no lease is held.
1125 * (if a lease break is pending):
1127 * %F_RDLCK to indicate an exclusive lease needs to be
1128 * changed to a shared lease (or removed).
1130 * %F_UNLCK to indicate the lease needs to be removed.
1132 * XXX: sfr & willy disagree over whether F_INPROGRESS
1133 * should be returned to userspace.
1135 int fcntl_getlease(struct file
*filp
)
1137 struct file_lock
*fl
;
1141 time_out_leases(filp
->f_dentry
->d_inode
);
1142 for (fl
= filp
->f_dentry
->d_inode
->i_flock
; fl
&& IS_LEASE(fl
);
1144 if (fl
->fl_file
== filp
) {
1145 type
= fl
->fl_type
& ~F_INPROGRESS
;
1154 * fcntl_setlease - sets a lease on an open file
1155 * @fd: open file descriptor
1156 * @filp: file pointer
1157 * @arg: type of lease to obtain
1159 * Call this fcntl to establish a lease on the file.
1160 * Note that you also need to call %F_SETSIG to
1161 * receive a signal when the lease is broken.
1163 int fcntl_setlease(unsigned int fd
, struct file
*filp
, long arg
)
1165 struct file_lock
*fl
, **before
, **my_before
= NULL
;
1166 struct dentry
*dentry
;
1167 struct inode
*inode
;
1168 int error
, rdlease_count
= 0, wrlease_count
= 0;
1170 dentry
= filp
->f_dentry
;
1171 inode
= dentry
->d_inode
;
1173 if ((current
->fsuid
!= inode
->i_uid
) && !capable(CAP_LEASE
))
1175 if (!S_ISREG(inode
->i_mode
))
1177 error
= security_ops
->file_lock(filp
, arg
);
1183 time_out_leases(inode
);
1186 * FIXME: What about F_RDLCK and files open for writing?
1189 if ((arg
== F_WRLCK
)
1190 && ((atomic_read(&dentry
->d_count
) > 1)
1191 || (atomic_read(&inode
->i_count
) > 1)))
1195 * At this point, we know that if there is an exclusive
1196 * lease on this file, then we hold it on this filp
1197 * (otherwise our open of this file would have blocked).
1198 * And if we are trying to acquire an exclusive lease,
1199 * then the file is not open by anyone (including us)
1200 * except for this filp.
1202 for (before
= &inode
->i_flock
;
1203 ((fl
= *before
) != NULL
) && IS_LEASE(fl
);
1204 before
= &fl
->fl_next
) {
1205 if (fl
->fl_file
== filp
)
1207 else if (fl
->fl_type
== (F_INPROGRESS
| F_UNLCK
))
1209 * Someone is in the process of opening this
1210 * file for writing so we may not take an
1211 * exclusive lease on it.
1218 if ((arg
== F_RDLCK
&& (wrlease_count
> 0)) ||
1219 (arg
== F_WRLCK
&& ((rdlease_count
+ wrlease_count
) > 0)))
1222 if (my_before
!= NULL
) {
1223 error
= lease_modify(my_before
, arg
);
1235 error
= lease_alloc(filp
, arg
, &fl
);
1239 error
= fasync_helper(fd
, filp
, 1, &fl
->fl_fasync
);
1241 locks_free_lock(fl
);
1244 fl
->fl_next
= *before
;
1246 list_add(&fl
->fl_link
, &file_lock_list
);
1248 error
= f_setown(filp
, current
->tgid
, 1);
1255 * sys_flock: - flock() system call.
1256 * @fd: the file descriptor to lock.
1257 * @cmd: the type of lock to apply.
1259 * Apply a %FL_FLOCK style lock to an open file descriptor.
1260 * The @cmd can be one of
1262 * %LOCK_SH -- a shared lock.
1264 * %LOCK_EX -- an exclusive lock.
1266 * %LOCK_UN -- remove an existing lock.
1268 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1270 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1271 * processes read and write access respectively.
1273 asmlinkage
long sys_flock(unsigned int fd
, unsigned int cmd
)
1276 struct file_lock
*lock
;
1284 if ((cmd
!= LOCK_UN
) && !(cmd
& LOCK_MAND
) && !(filp
->f_mode
& 3))
1287 error
= flock_make_lock(filp
, &lock
, cmd
);
1291 error
= security_ops
->file_lock(filp
, cmd
);
1296 error
= flock_lock_file(filp
, lock
);
1297 if ((error
!= -EAGAIN
) || (cmd
& LOCK_NB
))
1299 error
= wait_event_interruptible(lock
->fl_wait
, !lock
->fl_next
);
1304 locks_delete_block(lock
);
1311 locks_free_lock(lock
);
1320 /* Report the first existing lock that would conflict with l.
1321 * This implements the F_GETLK command of fcntl().
1323 int fcntl_getlk(struct file
*filp
, struct flock
*l
)
1325 struct file_lock
*fl
, file_lock
;
1330 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1333 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
1336 error
= flock_to_posix_lock(filp
, &file_lock
, &flock
);
1340 if (filp
->f_op
&& filp
->f_op
->lock
) {
1341 error
= filp
->f_op
->lock(filp
, F_GETLK
, &file_lock
);
1344 else if (error
== LOCK_USE_CLNT
)
1345 /* Bypass for NFS with no locking - 2.0.36 compat */
1346 fl
= posix_test_lock(filp
, &file_lock
);
1348 fl
= (file_lock
.fl_type
== F_UNLCK
? NULL
: &file_lock
);
1350 fl
= posix_test_lock(filp
, &file_lock
);
1353 flock
.l_type
= F_UNLCK
;
1355 flock
.l_pid
= fl
->fl_pid
;
1356 #if BITS_PER_LONG == 32
1358 * Make sure we can represent the posix lock via
1359 * legacy 32bit flock.
1362 if (fl
->fl_start
> OFFT_OFFSET_MAX
)
1364 if ((fl
->fl_end
!= OFFSET_MAX
)
1365 && (fl
->fl_end
> OFFT_OFFSET_MAX
))
1368 flock
.l_start
= fl
->fl_start
;
1369 flock
.l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1370 fl
->fl_end
- fl
->fl_start
+ 1;
1372 flock
.l_type
= fl
->fl_type
;
1375 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
1382 /* Apply the lock described by l to an open file descriptor.
1383 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1385 int fcntl_setlk(struct file
*filp
, unsigned int cmd
, struct flock
*l
)
1387 struct file_lock
*file_lock
= locks_alloc_lock(0);
1389 struct inode
*inode
;
1392 if (file_lock
== NULL
)
1396 * This might block, so we do it before checking the inode.
1399 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1402 inode
= filp
->f_dentry
->d_inode
;
1405 /* Don't allow mandatory locks on files that may be memory mapped
1408 if (IS_MANDLOCK(inode
) &&
1409 (inode
->i_mode
& (S_ISGID
| S_IXGRP
)) == S_ISGID
) {
1410 struct address_space
*mapping
= inode
->i_mapping
;
1412 if (!list_empty(&mapping
->i_mmap_shared
)) {
1419 error
= flock_to_posix_lock(filp
, file_lock
, &flock
);
1422 if (cmd
== F_SETLKW
) {
1423 file_lock
->fl_flags
|= FL_SLEEP
;
1427 switch (flock
.l_type
) {
1429 if (!(filp
->f_mode
& FMODE_READ
))
1433 if (!(filp
->f_mode
& FMODE_WRITE
))
1443 error
= security_ops
->file_lock(filp
, file_lock
->fl_type
);
1447 if (filp
->f_op
&& filp
->f_op
->lock
!= NULL
) {
1448 error
= filp
->f_op
->lock(filp
, cmd
, file_lock
);
1454 error
= posix_lock_file(filp
, file_lock
);
1455 if ((error
!= -EAGAIN
) || (cmd
== F_SETLK
))
1457 error
= wait_event_interruptible(file_lock
->fl_wait
,
1458 !file_lock
->fl_next
);
1463 locks_delete_block(file_lock
);
1469 locks_free_lock(file_lock
);
1473 #if BITS_PER_LONG == 32
1474 /* Report the first existing lock that would conflict with l.
1475 * This implements the F_GETLK command of fcntl().
1477 int fcntl_getlk64(struct file
*filp
, struct flock64
*l
)
1479 struct file_lock
*fl
, file_lock
;
1480 struct flock64 flock
;
1484 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1487 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
1490 error
= flock64_to_posix_lock(filp
, &file_lock
, &flock
);
1494 if (filp
->f_op
&& filp
->f_op
->lock
) {
1495 error
= filp
->f_op
->lock(filp
, F_GETLK
, &file_lock
);
1498 else if (error
== LOCK_USE_CLNT
)
1499 /* Bypass for NFS with no locking - 2.0.36 compat */
1500 fl
= posix_test_lock(filp
, &file_lock
);
1502 fl
= (file_lock
.fl_type
== F_UNLCK
? NULL
: &file_lock
);
1504 fl
= posix_test_lock(filp
, &file_lock
);
1507 flock
.l_type
= F_UNLCK
;
1509 flock
.l_pid
= fl
->fl_pid
;
1510 flock
.l_start
= fl
->fl_start
;
1511 flock
.l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1512 fl
->fl_end
- fl
->fl_start
+ 1;
1514 flock
.l_type
= fl
->fl_type
;
1517 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
1524 /* Apply the lock described by l to an open file descriptor.
1525 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
1527 int fcntl_setlk64(struct file
*filp
, unsigned int cmd
, struct flock64
*l
)
1529 struct file_lock
*file_lock
= locks_alloc_lock(0);
1530 struct flock64 flock
;
1531 struct inode
*inode
;
1534 if (file_lock
== NULL
)
1538 * This might block, so we do it before checking the inode.
1541 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1544 inode
= filp
->f_dentry
->d_inode
;
1546 /* Don't allow mandatory locks on files that may be memory mapped
1549 if (IS_MANDLOCK(inode
) &&
1550 (inode
->i_mode
& (S_ISGID
| S_IXGRP
)) == S_ISGID
) {
1551 struct address_space
*mapping
= inode
->i_mapping
;
1553 if (!list_empty(&mapping
->i_mmap_shared
)) {
1559 error
= flock64_to_posix_lock(filp
, file_lock
, &flock
);
1562 if (cmd
== F_SETLKW64
) {
1563 file_lock
->fl_flags
|= FL_SLEEP
;
1567 switch (flock
.l_type
) {
1569 if (!(filp
->f_mode
& FMODE_READ
))
1573 if (!(filp
->f_mode
& FMODE_WRITE
))
1583 error
= security_ops
->file_lock(filp
, file_lock
->fl_type
);
1587 if (filp
->f_op
&& filp
->f_op
->lock
!= NULL
) {
1588 error
= filp
->f_op
->lock(filp
, cmd
, file_lock
);
1594 error
= posix_lock_file(filp
, file_lock
);
1595 if ((error
!= -EAGAIN
) || (cmd
== F_SETLK64
))
1597 error
= wait_event_interruptible(file_lock
->fl_wait
,
1598 !file_lock
->fl_next
);
1603 locks_delete_block(file_lock
);
1609 locks_free_lock(file_lock
);
1612 #endif /* BITS_PER_LONG == 32 */
1615 * This function is called when the file is being removed
1616 * from the task's fd array. POSIX locks belonging to this task
1617 * are deleted at this time.
1619 void locks_remove_posix(struct file
*filp
, fl_owner_t owner
)
1621 struct file_lock lock
;
1624 * If there are no locks held on this file, we don't need to call
1625 * posix_lock_file(). Another process could be setting a lock on this
1626 * file at the same time, but we wouldn't remove that lock anyway.
1628 if (!filp
->f_dentry
->d_inode
->i_flock
)
1631 lock
.fl_type
= F_UNLCK
;
1632 lock
.fl_flags
= FL_POSIX
;
1634 lock
.fl_end
= OFFSET_MAX
;
1635 lock
.fl_owner
= owner
;
1636 lock
.fl_pid
= current
->tgid
;
1637 lock
.fl_file
= filp
;
1639 if (filp
->f_op
&& filp
->f_op
->lock
!= NULL
) {
1640 filp
->f_op
->lock(filp
, F_SETLK
, &lock
);
1641 /* Ignore any error -- we must remove the locks anyway */
1644 posix_lock_file(filp
, &lock
);
1648 * This function is called on the last close of an open file.
1650 void locks_remove_flock(struct file
*filp
)
1652 struct inode
* inode
= filp
->f_dentry
->d_inode
;
1653 struct file_lock
*fl
;
1654 struct file_lock
**before
;
1656 if (!inode
->i_flock
)
1660 before
= &inode
->i_flock
;
1662 while ((fl
= *before
) != NULL
) {
1663 if (fl
->fl_file
== filp
) {
1665 locks_delete_lock(before
);
1669 lease_modify(before
, F_UNLCK
);
1673 before
= &fl
->fl_next
;
1679 * posix_block_lock - blocks waiting for a file lock
1680 * @blocker: the lock which is blocking
1681 * @waiter: the lock which conflicts and has to wait
1683 * lockd needs to block waiting for locks.
1686 posix_block_lock(struct file_lock
*blocker
, struct file_lock
*waiter
)
1688 locks_insert_block(blocker
, waiter
);
1692 * posix_unblock_lock - stop waiting for a file lock
1693 * @waiter: the lock which was waiting
1695 * lockd needs to block waiting for locks.
1698 posix_unblock_lock(struct file
*filp
, struct file_lock
*waiter
)
1701 * A remote machine may cancel the lock request after it's been
1702 * granted locally. If that happens, we need to delete the lock.
1705 if (waiter
->fl_next
) {
1706 locks_delete_block(waiter
);
1710 waiter
->fl_type
= F_UNLCK
;
1711 posix_lock_file(filp
, waiter
);
1715 static void lock_get_status(char* out
, struct file_lock
*fl
, int id
, char *pfx
)
1717 struct inode
*inode
= NULL
;
1719 if (fl
->fl_file
!= NULL
)
1720 inode
= fl
->fl_file
->f_dentry
->d_inode
;
1722 out
+= sprintf(out
, "%d:%s ", id
, pfx
);
1724 out
+= sprintf(out
, "%6s %s ",
1725 (fl
->fl_flags
& FL_ACCESS
) ? "ACCESS" : "POSIX ",
1726 (inode
== NULL
) ? "*NOINODE*" :
1727 (IS_MANDLOCK(inode
) &&
1728 (inode
->i_mode
& (S_IXGRP
| S_ISGID
)) == S_ISGID
) ?
1729 "MANDATORY" : "ADVISORY ");
1730 } else if (IS_FLOCK(fl
)) {
1731 if (fl
->fl_type
& LOCK_MAND
) {
1732 out
+= sprintf(out
, "FLOCK MSNFS ");
1734 out
+= sprintf(out
, "FLOCK ADVISORY ");
1736 } else if (IS_LEASE(fl
)) {
1737 out
+= sprintf(out
, "LEASE ");
1738 if (fl
->fl_type
& F_INPROGRESS
)
1739 out
+= sprintf(out
, "BREAKING ");
1740 else if (fl
->fl_file
)
1741 out
+= sprintf(out
, "ACTIVE ");
1743 out
+= sprintf(out
, "BREAKER ");
1745 out
+= sprintf(out
, "UNKNOWN UNKNOWN ");
1747 if (fl
->fl_type
& LOCK_MAND
) {
1748 out
+= sprintf(out
, "%s ",
1749 (fl
->fl_type
& LOCK_READ
)
1750 ? (fl
->fl_type
& LOCK_WRITE
) ? "RW " : "READ "
1751 : (fl
->fl_type
& LOCK_WRITE
) ? "WRITE" : "NONE ");
1753 out
+= sprintf(out
, "%s ",
1754 (fl
->fl_type
& F_INPROGRESS
)
1755 ? (fl
->fl_type
& F_UNLCK
) ? "UNLCK" : "READ "
1756 : (fl
->fl_type
& F_WRLCK
) ? "WRITE" : "READ ");
1758 #if WE_CAN_BREAK_LSLK_NOW
1760 out
+= sprintf(out
, "%d %s:%ld ", fl
->fl_pid
,
1761 inode
->i_sb
->s_id
, inode
->i_ino
);
1763 out
+= sprintf(out
, "%d <none>:0 ", fl
->fl_pid
);
1766 /* kdevname is a broken interface. but we expose it to userspace */
1767 out
+= sprintf(out
, "%d %s:%ld ", fl
->fl_pid
,
1768 inode
? kdevname(to_kdev_t(inode
->i_dev
)) : "<none>",
1769 inode
? inode
->i_ino
: 0);
1772 if (fl
->fl_end
== OFFSET_MAX
)
1773 out
+= sprintf(out
, "%Ld EOF\n", fl
->fl_start
);
1775 out
+= sprintf(out
, "%Ld %Ld\n", fl
->fl_start
,
1778 out
+= sprintf(out
, "0 EOF\n");
1782 static void move_lock_status(char **p
, off_t
* pos
, off_t offset
)
1786 if(*pos
>= offset
) {
1787 /* the complete line is valid */
1792 if(*pos
+len
> offset
) {
1793 /* use the second part of the line */
1794 int i
= offset
-*pos
;
1795 memmove(*p
,*p
+i
,len
-i
);
1800 /* discard the complete line */
1805 * get_locks_status - reports lock usage in /proc/locks
1806 * @buffer: address in userspace to write into
1808 * @offset: how far we are through the buffer
1809 * @length: how much to read
1812 int get_locks_status(char *buffer
, char **start
, off_t offset
, int length
)
1814 struct list_head
*tmp
;
1820 list_for_each(tmp
, &file_lock_list
) {
1821 struct list_head
*btmp
;
1822 struct file_lock
*fl
= list_entry(tmp
, struct file_lock
, fl_link
);
1823 lock_get_status(q
, fl
, ++i
, "");
1824 move_lock_status(&q
, &pos
, offset
);
1826 if(pos
>= offset
+length
)
1829 list_for_each(btmp
, &fl
->fl_block
) {
1830 struct file_lock
*bfl
= list_entry(btmp
,
1831 struct file_lock
, fl_block
);
1832 lock_get_status(q
, bfl
, i
, " ->");
1833 move_lock_status(&q
, &pos
, offset
);
1835 if(pos
>= offset
+length
)
1842 if(q
-buffer
< length
)
1848 * lock_may_read - checks that the region is free of locks
1849 * @inode: the inode that is being read
1850 * @start: the first byte to read
1851 * @len: the number of bytes to read
1853 * Emulates Windows locking requirements. Whole-file
1854 * mandatory locks (share modes) can prohibit a read and
1855 * byte-range POSIX locks can prohibit a read if they overlap.
1857 * N.B. this function is only ever called
1858 * from knfsd and ownership of locks is never checked.
1860 int lock_may_read(struct inode
*inode
, loff_t start
, unsigned long len
)
1862 struct file_lock
*fl
;
1865 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
1867 if (fl
->fl_type
== F_RDLCK
)
1869 if ((fl
->fl_end
< start
) || (fl
->fl_start
> (start
+ len
)))
1871 } else if (IS_FLOCK(fl
)) {
1872 if (!(fl
->fl_type
& LOCK_MAND
))
1874 if (fl
->fl_type
& LOCK_READ
)
1886 * lock_may_write - checks that the region is free of locks
1887 * @inode: the inode that is being written
1888 * @start: the first byte to write
1889 * @len: the number of bytes to write
1891 * Emulates Windows locking requirements. Whole-file
1892 * mandatory locks (share modes) can prohibit a write and
1893 * byte-range POSIX locks can prohibit a write if they overlap.
1895 * N.B. this function is only ever called
1896 * from knfsd and ownership of locks is never checked.
1898 int lock_may_write(struct inode
*inode
, loff_t start
, unsigned long len
)
1900 struct file_lock
*fl
;
1903 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
1905 if ((fl
->fl_end
< start
) || (fl
->fl_start
> (start
+ len
)))
1907 } else if (IS_FLOCK(fl
)) {
1908 if (!(fl
->fl_type
& LOCK_MAND
))
1910 if (fl
->fl_type
& LOCK_WRITE
)
1921 static int __init
filelock_init(void)
1923 filelock_cache
= kmem_cache_create("file_lock_cache",
1924 sizeof(struct file_lock
), 0, 0, init_once
, NULL
);
1925 if (!filelock_cache
)
1926 panic("cannot create file lock slab cache");
1930 module_init(filelock_init
)