4 * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
5 * Doug Evans (dje@spiff.uucp), August 07, 1992
7 * Deadlock detection added.
8 * FIXME: one thing isn't handled yet:
9 * - mandatory locks (requires lots of changes elsewhere)
10 * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
12 * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
13 * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
15 * Converted file_lock_table to a linked list from an array, which eliminates
16 * the limits on how many active file locks are open.
17 * Chad Page (pageone@netcom.com), November 27, 1994
19 * Removed dependency on file descriptors. dup()'ed file descriptors now
20 * get the same locks as the original file descriptors, and a close() on
21 * any file descriptor removes ALL the locks on the file for the current
22 * process. Since locks still depend on the process id, locks are inherited
23 * after an exec() but not after a fork(). This agrees with POSIX, and both
24 * BSD and SVR4 practice.
25 * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
27 * Scrapped free list which is redundant now that we allocate locks
28 * dynamically with kmalloc()/kfree().
29 * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
31 * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
33 * FL_POSIX locks are created with calls to fcntl() and lockf() through the
34 * fcntl() system call. They have the semantics described above.
36 * FL_FLOCK locks are created with calls to flock(), through the flock()
37 * system call, which is new. Old C libraries implement flock() via fcntl()
38 * and will continue to use the old, broken implementation.
40 * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
41 * with a file pointer (filp). As a result they can be shared by a parent
42 * process and its children after a fork(). They are removed when the last
43 * file descriptor referring to the file pointer is closed (unless explicitly
46 * FL_FLOCK locks never deadlock, an existing lock is always removed before
47 * upgrading from shared to exclusive (or vice versa). When this happens
48 * any processes blocked by the current lock are woken up and allowed to
49 * run before the new lock is applied.
50 * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
52 * Removed some race conditions in flock_lock_file(), marked other possible
53 * races. Just grep for FIXME to see them.
54 * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
56 * Addressed Dmitry's concerns. Deadlock checking no longer recursive.
57 * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
58 * once we've checked for blocking and deadlocking.
59 * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
61 * Initial implementation of mandatory locks. SunOS turned out to be
62 * a rotten model, so I implemented the "obvious" semantics.
63 * See 'Documentation/filesystems/mandatory-locking.txt' for details.
64 * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
66 * Don't allow mandatory locks on mmap()'ed files. Added simple functions to
67 * check if a file has mandatory locks, used by mmap(), open() and creat() to
68 * see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
70 * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
72 * Tidied up block list handling. Added '/proc/locks' interface.
73 * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
75 * Fixed deadlock condition for pathological code that mixes calls to
76 * flock() and fcntl().
77 * Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
79 * Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
80 * for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
81 * guarantee sensible behaviour in the case where file system modules might
82 * be compiled with different options than the kernel itself.
83 * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
85 * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
86 * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
87 * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
89 * Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
90 * locks. Changed process synchronisation to avoid dereferencing locks that
91 * have already been freed.
92 * Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
94 * Made the block list a circular list to minimise searching in the list.
95 * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
97 * Made mandatory locking a mount option. Default is not to allow mandatory
99 * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
101 * Some adaptations for NFS support.
102 * Olaf Kirch (okir@monad.swb.de), Dec 1996,
104 * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
105 * Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
107 * Use slab allocator instead of kmalloc/kfree.
108 * Use generic list implementation from <linux/list.h>.
109 * Sped up posix_locks_deadlock by only considering blocked locks.
110 * Matthew Wilcox <willy@debian.org>, March, 2000.
112 * Leases and LOCK_MAND
113 * Matthew Wilcox <willy@debian.org>, June, 2000.
114 * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
117 #include <linux/capability.h>
118 #include <linux/file.h>
119 #include <linux/fdtable.h>
120 #include <linux/fs.h>
121 #include <linux/init.h>
122 #include <linux/module.h>
123 #include <linux/security.h>
124 #include <linux/slab.h>
125 #include <linux/syscalls.h>
126 #include <linux/time.h>
127 #include <linux/rcupdate.h>
128 #include <linux/pid_namespace.h>
129 #include <linux/hashtable.h>
130 #include <linux/percpu.h>
131 #include <linux/lglock.h>
133 #define CREATE_TRACE_POINTS
134 #include <trace/events/filelock.h>
136 #include <asm/uaccess.h>
138 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
139 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
140 #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG))
141 #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
143 static bool lease_breaking(struct file_lock
*fl
)
145 return fl
->fl_flags
& (FL_UNLOCK_PENDING
| FL_DOWNGRADE_PENDING
);
148 static int target_leasetype(struct file_lock
*fl
)
150 if (fl
->fl_flags
& FL_UNLOCK_PENDING
)
152 if (fl
->fl_flags
& FL_DOWNGRADE_PENDING
)
157 int leases_enable
= 1;
158 int lease_break_time
= 45;
160 #define for_each_lock(inode, lockp) \
161 for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
164 * The global file_lock_list is only used for displaying /proc/locks, so we
165 * keep a list on each CPU, with each list protected by its own spinlock via
166 * the file_lock_lglock. Note that alterations to the list also require that
167 * the relevant i_lock is held.
169 DEFINE_STATIC_LGLOCK(file_lock_lglock
);
170 static DEFINE_PER_CPU(struct hlist_head
, file_lock_list
);
173 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
174 * It is protected by blocked_lock_lock.
176 * We hash locks by lockowner in order to optimize searching for the lock a
177 * particular lockowner is waiting on.
179 * FIXME: make this value scale via some heuristic? We generally will want more
180 * buckets when we have more lockowners holding locks, but that's a little
181 * difficult to determine without knowing what the workload will look like.
183 #define BLOCKED_HASH_BITS 7
184 static DEFINE_HASHTABLE(blocked_hash
, BLOCKED_HASH_BITS
);
187 * This lock protects the blocked_hash. Generally, if you're accessing it, you
188 * want to be holding this lock.
190 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
191 * pointer for file_lock structures that are acting as lock requests (in
192 * contrast to those that are acting as records of acquired locks).
194 * Note that when we acquire this lock in order to change the above fields,
195 * we often hold the i_lock as well. In certain cases, when reading the fields
196 * protected by this lock, we can skip acquiring it iff we already hold the
199 * In particular, adding an entry to the fl_block list requires that you hold
200 * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting
201 * an entry from the list however only requires the file_lock_lock.
203 static DEFINE_SPINLOCK(blocked_lock_lock
);
205 static struct kmem_cache
*filelock_cache __read_mostly
;
207 static void locks_init_lock_heads(struct file_lock
*fl
)
209 INIT_HLIST_NODE(&fl
->fl_link
);
210 INIT_LIST_HEAD(&fl
->fl_block
);
211 init_waitqueue_head(&fl
->fl_wait
);
214 /* Allocate an empty lock structure. */
215 struct file_lock
*locks_alloc_lock(void)
217 struct file_lock
*fl
= kmem_cache_zalloc(filelock_cache
, GFP_KERNEL
);
220 locks_init_lock_heads(fl
);
224 EXPORT_SYMBOL_GPL(locks_alloc_lock
);
226 void locks_release_private(struct file_lock
*fl
)
229 if (fl
->fl_ops
->fl_release_private
)
230 fl
->fl_ops
->fl_release_private(fl
);
235 if (fl
->fl_lmops
->lm_put_owner
)
236 fl
->fl_lmops
->lm_put_owner(fl
);
240 EXPORT_SYMBOL_GPL(locks_release_private
);
242 /* Free a lock which is not in use. */
243 void locks_free_lock(struct file_lock
*fl
)
245 BUG_ON(waitqueue_active(&fl
->fl_wait
));
246 BUG_ON(!list_empty(&fl
->fl_block
));
247 BUG_ON(!hlist_unhashed(&fl
->fl_link
));
249 locks_release_private(fl
);
250 kmem_cache_free(filelock_cache
, fl
);
252 EXPORT_SYMBOL(locks_free_lock
);
255 locks_dispose_list(struct list_head
*dispose
)
257 struct file_lock
*fl
;
259 while (!list_empty(dispose
)) {
260 fl
= list_first_entry(dispose
, struct file_lock
, fl_block
);
261 list_del_init(&fl
->fl_block
);
266 void locks_init_lock(struct file_lock
*fl
)
268 memset(fl
, 0, sizeof(struct file_lock
));
269 locks_init_lock_heads(fl
);
272 EXPORT_SYMBOL(locks_init_lock
);
275 * Initialize a new lock from an existing file_lock structure.
277 void locks_copy_conflock(struct file_lock
*new, struct file_lock
*fl
)
279 new->fl_owner
= fl
->fl_owner
;
280 new->fl_pid
= fl
->fl_pid
;
282 new->fl_flags
= fl
->fl_flags
;
283 new->fl_type
= fl
->fl_type
;
284 new->fl_start
= fl
->fl_start
;
285 new->fl_end
= fl
->fl_end
;
286 new->fl_lmops
= fl
->fl_lmops
;
290 if (fl
->fl_lmops
->lm_get_owner
)
291 fl
->fl_lmops
->lm_get_owner(new, fl
);
294 EXPORT_SYMBOL(locks_copy_conflock
);
296 void locks_copy_lock(struct file_lock
*new, struct file_lock
*fl
)
298 /* "new" must be a freshly-initialized lock */
299 WARN_ON_ONCE(new->fl_ops
);
301 locks_copy_conflock(new, fl
);
303 new->fl_file
= fl
->fl_file
;
304 new->fl_ops
= fl
->fl_ops
;
307 if (fl
->fl_ops
->fl_copy_lock
)
308 fl
->fl_ops
->fl_copy_lock(new, fl
);
312 EXPORT_SYMBOL(locks_copy_lock
);
314 static inline int flock_translate_cmd(int cmd
) {
316 return cmd
& (LOCK_MAND
| LOCK_RW
);
328 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
329 static int flock_make_lock(struct file
*filp
, struct file_lock
**lock
,
332 struct file_lock
*fl
;
333 int type
= flock_translate_cmd(cmd
);
337 fl
= locks_alloc_lock();
343 fl
->fl_pid
= current
->tgid
;
344 fl
->fl_flags
= FL_FLOCK
;
346 fl
->fl_end
= OFFSET_MAX
;
352 static int assign_type(struct file_lock
*fl
, long type
)
366 static int flock64_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
369 switch (l
->l_whence
) {
374 fl
->fl_start
= filp
->f_pos
;
377 fl
->fl_start
= i_size_read(file_inode(filp
));
382 if (l
->l_start
> OFFSET_MAX
- fl
->fl_start
)
384 fl
->fl_start
+= l
->l_start
;
385 if (fl
->fl_start
< 0)
388 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
389 POSIX-2001 defines it. */
391 if (l
->l_len
- 1 > OFFSET_MAX
- fl
->fl_start
)
393 fl
->fl_end
= fl
->fl_start
+ l
->l_len
- 1;
395 } else if (l
->l_len
< 0) {
396 if (fl
->fl_start
+ l
->l_len
< 0)
398 fl
->fl_end
= fl
->fl_start
- 1;
399 fl
->fl_start
+= l
->l_len
;
401 fl
->fl_end
= OFFSET_MAX
;
403 fl
->fl_owner
= current
->files
;
404 fl
->fl_pid
= current
->tgid
;
406 fl
->fl_flags
= FL_POSIX
;
410 return assign_type(fl
, l
->l_type
);
413 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
416 static int flock_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
419 struct flock64 ll
= {
421 .l_whence
= l
->l_whence
,
422 .l_start
= l
->l_start
,
426 return flock64_to_posix_lock(filp
, fl
, &ll
);
429 /* default lease lock manager operations */
430 static void lease_break_callback(struct file_lock
*fl
)
432 kill_fasync(&fl
->fl_fasync
, SIGIO
, POLL_MSG
);
436 lease_setup(struct file_lock
*fl
, void **priv
)
438 struct file
*filp
= fl
->fl_file
;
439 struct fasync_struct
*fa
= *priv
;
442 * fasync_insert_entry() returns the old entry if any. If there was no
443 * old entry, then it used "priv" and inserted it into the fasync list.
444 * Clear the pointer to indicate that it shouldn't be freed.
446 if (!fasync_insert_entry(fa
->fa_fd
, filp
, &fl
->fl_fasync
, fa
))
449 __f_setown(filp
, task_pid(current
), PIDTYPE_PID
, 0);
452 static const struct lock_manager_operations lease_manager_ops
= {
453 .lm_break
= lease_break_callback
,
454 .lm_change
= lease_modify
,
455 .lm_setup
= lease_setup
,
459 * Initialize a lease, use the default lock manager operations
461 static int lease_init(struct file
*filp
, long type
, struct file_lock
*fl
)
463 if (assign_type(fl
, type
) != 0)
466 fl
->fl_owner
= current
->files
;
467 fl
->fl_pid
= current
->tgid
;
470 fl
->fl_flags
= FL_LEASE
;
472 fl
->fl_end
= OFFSET_MAX
;
474 fl
->fl_lmops
= &lease_manager_ops
;
478 /* Allocate a file_lock initialised to this type of lease */
479 static struct file_lock
*lease_alloc(struct file
*filp
, long type
)
481 struct file_lock
*fl
= locks_alloc_lock();
485 return ERR_PTR(error
);
487 error
= lease_init(filp
, type
, fl
);
490 return ERR_PTR(error
);
495 /* Check if two locks overlap each other.
497 static inline int locks_overlap(struct file_lock
*fl1
, struct file_lock
*fl2
)
499 return ((fl1
->fl_end
>= fl2
->fl_start
) &&
500 (fl2
->fl_end
>= fl1
->fl_start
));
504 * Check whether two locks have the same owner.
506 static int posix_same_owner(struct file_lock
*fl1
, struct file_lock
*fl2
)
508 if (fl1
->fl_lmops
&& fl1
->fl_lmops
->lm_compare_owner
)
509 return fl2
->fl_lmops
== fl1
->fl_lmops
&&
510 fl1
->fl_lmops
->lm_compare_owner(fl1
, fl2
);
511 return fl1
->fl_owner
== fl2
->fl_owner
;
514 /* Must be called with the i_lock held! */
515 static void locks_insert_global_locks(struct file_lock
*fl
)
517 lg_local_lock(&file_lock_lglock
);
518 fl
->fl_link_cpu
= smp_processor_id();
519 hlist_add_head(&fl
->fl_link
, this_cpu_ptr(&file_lock_list
));
520 lg_local_unlock(&file_lock_lglock
);
523 /* Must be called with the i_lock held! */
524 static void locks_delete_global_locks(struct file_lock
*fl
)
527 * Avoid taking lock if already unhashed. This is safe since this check
528 * is done while holding the i_lock, and new insertions into the list
529 * also require that it be held.
531 if (hlist_unhashed(&fl
->fl_link
))
533 lg_local_lock_cpu(&file_lock_lglock
, fl
->fl_link_cpu
);
534 hlist_del_init(&fl
->fl_link
);
535 lg_local_unlock_cpu(&file_lock_lglock
, fl
->fl_link_cpu
);
539 posix_owner_key(struct file_lock
*fl
)
541 if (fl
->fl_lmops
&& fl
->fl_lmops
->lm_owner_key
)
542 return fl
->fl_lmops
->lm_owner_key(fl
);
543 return (unsigned long)fl
->fl_owner
;
546 static void locks_insert_global_blocked(struct file_lock
*waiter
)
548 hash_add(blocked_hash
, &waiter
->fl_link
, posix_owner_key(waiter
));
551 static void locks_delete_global_blocked(struct file_lock
*waiter
)
553 hash_del(&waiter
->fl_link
);
556 /* Remove waiter from blocker's block list.
557 * When blocker ends up pointing to itself then the list is empty.
559 * Must be called with blocked_lock_lock held.
561 static void __locks_delete_block(struct file_lock
*waiter
)
563 locks_delete_global_blocked(waiter
);
564 list_del_init(&waiter
->fl_block
);
565 waiter
->fl_next
= NULL
;
568 static void locks_delete_block(struct file_lock
*waiter
)
570 spin_lock(&blocked_lock_lock
);
571 __locks_delete_block(waiter
);
572 spin_unlock(&blocked_lock_lock
);
575 /* Insert waiter into blocker's block list.
576 * We use a circular list so that processes can be easily woken up in
577 * the order they blocked. The documentation doesn't require this but
578 * it seems like the reasonable thing to do.
580 * Must be called with both the i_lock and blocked_lock_lock held. The fl_block
581 * list itself is protected by the blocked_lock_lock, but by ensuring that the
582 * i_lock is also held on insertions we can avoid taking the blocked_lock_lock
583 * in some cases when we see that the fl_block list is empty.
585 static void __locks_insert_block(struct file_lock
*blocker
,
586 struct file_lock
*waiter
)
588 BUG_ON(!list_empty(&waiter
->fl_block
));
589 waiter
->fl_next
= blocker
;
590 list_add_tail(&waiter
->fl_block
, &blocker
->fl_block
);
591 if (IS_POSIX(blocker
) && !IS_OFDLCK(blocker
))
592 locks_insert_global_blocked(waiter
);
595 /* Must be called with i_lock held. */
596 static void locks_insert_block(struct file_lock
*blocker
,
597 struct file_lock
*waiter
)
599 spin_lock(&blocked_lock_lock
);
600 __locks_insert_block(blocker
, waiter
);
601 spin_unlock(&blocked_lock_lock
);
605 * Wake up processes blocked waiting for blocker.
607 * Must be called with the inode->i_lock held!
609 static void locks_wake_up_blocks(struct file_lock
*blocker
)
612 * Avoid taking global lock if list is empty. This is safe since new
613 * blocked requests are only added to the list under the i_lock, and
614 * the i_lock is always held here. Note that removal from the fl_block
615 * list does not require the i_lock, so we must recheck list_empty()
616 * after acquiring the blocked_lock_lock.
618 if (list_empty(&blocker
->fl_block
))
621 spin_lock(&blocked_lock_lock
);
622 while (!list_empty(&blocker
->fl_block
)) {
623 struct file_lock
*waiter
;
625 waiter
= list_first_entry(&blocker
->fl_block
,
626 struct file_lock
, fl_block
);
627 __locks_delete_block(waiter
);
628 if (waiter
->fl_lmops
&& waiter
->fl_lmops
->lm_notify
)
629 waiter
->fl_lmops
->lm_notify(waiter
);
631 wake_up(&waiter
->fl_wait
);
633 spin_unlock(&blocked_lock_lock
);
636 /* Insert file lock fl into an inode's lock list at the position indicated
637 * by pos. At the same time add the lock to the global file lock list.
639 * Must be called with the i_lock held!
641 static void locks_insert_lock(struct file_lock
**pos
, struct file_lock
*fl
)
643 fl
->fl_nspid
= get_pid(task_tgid(current
));
645 /* insert into file's list */
649 locks_insert_global_locks(fl
);
653 * locks_delete_lock - Delete a lock and then free it.
654 * @thisfl_p: pointer that points to the fl_next field of the previous
655 * inode->i_flock list entry
657 * Unlink a lock from all lists and free the namespace reference, but don't
658 * free it yet. Wake up processes that are blocked waiting for this lock and
659 * notify the FS that the lock has been cleared.
661 * Must be called with the i_lock held!
663 static void locks_unlink_lock(struct file_lock
**thisfl_p
)
665 struct file_lock
*fl
= *thisfl_p
;
667 locks_delete_global_locks(fl
);
669 *thisfl_p
= fl
->fl_next
;
673 put_pid(fl
->fl_nspid
);
677 locks_wake_up_blocks(fl
);
681 * Unlink a lock from all lists and free it.
683 * Must be called with i_lock held!
685 static void locks_delete_lock(struct file_lock
**thisfl_p
,
686 struct list_head
*dispose
)
688 struct file_lock
*fl
= *thisfl_p
;
690 locks_unlink_lock(thisfl_p
);
692 list_add(&fl
->fl_block
, dispose
);
697 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
698 * checks for shared/exclusive status of overlapping locks.
700 static int locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
702 if (sys_fl
->fl_type
== F_WRLCK
)
704 if (caller_fl
->fl_type
== F_WRLCK
)
709 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
710 * checking before calling the locks_conflict().
712 static int posix_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
714 /* POSIX locks owned by the same process do not conflict with
717 if (!IS_POSIX(sys_fl
) || posix_same_owner(caller_fl
, sys_fl
))
720 /* Check whether they overlap */
721 if (!locks_overlap(caller_fl
, sys_fl
))
724 return (locks_conflict(caller_fl
, sys_fl
));
727 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
728 * checking before calling the locks_conflict().
730 static int flock_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
732 /* FLOCK locks referring to the same filp do not conflict with
735 if (!IS_FLOCK(sys_fl
) || (caller_fl
->fl_file
== sys_fl
->fl_file
))
737 if ((caller_fl
->fl_type
& LOCK_MAND
) || (sys_fl
->fl_type
& LOCK_MAND
))
740 return (locks_conflict(caller_fl
, sys_fl
));
744 posix_test_lock(struct file
*filp
, struct file_lock
*fl
)
746 struct file_lock
*cfl
;
747 struct inode
*inode
= file_inode(filp
);
749 spin_lock(&inode
->i_lock
);
750 for (cfl
= file_inode(filp
)->i_flock
; cfl
; cfl
= cfl
->fl_next
) {
753 if (posix_locks_conflict(fl
, cfl
))
757 locks_copy_conflock(fl
, cfl
);
759 fl
->fl_pid
= pid_vnr(cfl
->fl_nspid
);
761 fl
->fl_type
= F_UNLCK
;
762 spin_unlock(&inode
->i_lock
);
765 EXPORT_SYMBOL(posix_test_lock
);
768 * Deadlock detection:
770 * We attempt to detect deadlocks that are due purely to posix file
773 * We assume that a task can be waiting for at most one lock at a time.
774 * So for any acquired lock, the process holding that lock may be
775 * waiting on at most one other lock. That lock in turns may be held by
776 * someone waiting for at most one other lock. Given a requested lock
777 * caller_fl which is about to wait for a conflicting lock block_fl, we
778 * follow this chain of waiters to ensure we are not about to create a
781 * Since we do this before we ever put a process to sleep on a lock, we
782 * are ensured that there is never a cycle; that is what guarantees that
783 * the while() loop in posix_locks_deadlock() eventually completes.
785 * Note: the above assumption may not be true when handling lock
786 * requests from a broken NFS client. It may also fail in the presence
787 * of tasks (such as posix threads) sharing the same open file table.
788 * To handle those cases, we just bail out after a few iterations.
790 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
791 * Because the owner is not even nominally tied to a thread of
792 * execution, the deadlock detection below can't reasonably work well. Just
795 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
796 * locks that just checks for the case where two tasks are attempting to
797 * upgrade from read to write locks on the same inode.
800 #define MAX_DEADLK_ITERATIONS 10
802 /* Find a lock that the owner of the given block_fl is blocking on. */
803 static struct file_lock
*what_owner_is_waiting_for(struct file_lock
*block_fl
)
805 struct file_lock
*fl
;
807 hash_for_each_possible(blocked_hash
, fl
, fl_link
, posix_owner_key(block_fl
)) {
808 if (posix_same_owner(fl
, block_fl
))
814 /* Must be called with the blocked_lock_lock held! */
815 static int posix_locks_deadlock(struct file_lock
*caller_fl
,
816 struct file_lock
*block_fl
)
821 * This deadlock detector can't reasonably detect deadlocks with
822 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
824 if (IS_OFDLCK(caller_fl
))
827 while ((block_fl
= what_owner_is_waiting_for(block_fl
))) {
828 if (i
++ > MAX_DEADLK_ITERATIONS
)
830 if (posix_same_owner(caller_fl
, block_fl
))
836 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
837 * after any leases, but before any posix locks.
839 * Note that if called with an FL_EXISTS argument, the caller may determine
840 * whether or not a lock was successfully freed by testing the return
843 static int flock_lock_file(struct file
*filp
, struct file_lock
*request
)
845 struct file_lock
*new_fl
= NULL
;
846 struct file_lock
**before
;
847 struct inode
* inode
= file_inode(filp
);
852 if (!(request
->fl_flags
& FL_ACCESS
) && (request
->fl_type
!= F_UNLCK
)) {
853 new_fl
= locks_alloc_lock();
858 spin_lock(&inode
->i_lock
);
859 if (request
->fl_flags
& FL_ACCESS
)
862 for_each_lock(inode
, before
) {
863 struct file_lock
*fl
= *before
;
868 if (filp
!= fl
->fl_file
)
870 if (request
->fl_type
== fl
->fl_type
)
873 locks_delete_lock(before
, &dispose
);
877 if (request
->fl_type
== F_UNLCK
) {
878 if ((request
->fl_flags
& FL_EXISTS
) && !found
)
884 * If a higher-priority process was blocked on the old file lock,
885 * give it the opportunity to lock the file.
888 spin_unlock(&inode
->i_lock
);
890 spin_lock(&inode
->i_lock
);
894 for_each_lock(inode
, before
) {
895 struct file_lock
*fl
= *before
;
900 if (!flock_locks_conflict(request
, fl
))
903 if (!(request
->fl_flags
& FL_SLEEP
))
905 error
= FILE_LOCK_DEFERRED
;
906 locks_insert_block(fl
, request
);
909 if (request
->fl_flags
& FL_ACCESS
)
911 locks_copy_lock(new_fl
, request
);
912 locks_insert_lock(before
, new_fl
);
917 spin_unlock(&inode
->i_lock
);
919 locks_free_lock(new_fl
);
920 locks_dispose_list(&dispose
);
924 static int __posix_lock_file(struct inode
*inode
, struct file_lock
*request
, struct file_lock
*conflock
)
926 struct file_lock
*fl
;
927 struct file_lock
*new_fl
= NULL
;
928 struct file_lock
*new_fl2
= NULL
;
929 struct file_lock
*left
= NULL
;
930 struct file_lock
*right
= NULL
;
931 struct file_lock
**before
;
937 * We may need two file_lock structures for this operation,
938 * so we get them in advance to avoid races.
940 * In some cases we can be sure, that no new locks will be needed
942 if (!(request
->fl_flags
& FL_ACCESS
) &&
943 (request
->fl_type
!= F_UNLCK
||
944 request
->fl_start
!= 0 || request
->fl_end
!= OFFSET_MAX
)) {
945 new_fl
= locks_alloc_lock();
946 new_fl2
= locks_alloc_lock();
949 spin_lock(&inode
->i_lock
);
951 * New lock request. Walk all POSIX locks and look for conflicts. If
952 * there are any, either return error or put the request on the
953 * blocker's list of waiters and the global blocked_hash.
955 if (request
->fl_type
!= F_UNLCK
) {
956 for_each_lock(inode
, before
) {
960 if (!posix_locks_conflict(request
, fl
))
963 locks_copy_conflock(conflock
, fl
);
965 if (!(request
->fl_flags
& FL_SLEEP
))
968 * Deadlock detection and insertion into the blocked
969 * locks list must be done while holding the same lock!
972 spin_lock(&blocked_lock_lock
);
973 if (likely(!posix_locks_deadlock(request
, fl
))) {
974 error
= FILE_LOCK_DEFERRED
;
975 __locks_insert_block(fl
, request
);
977 spin_unlock(&blocked_lock_lock
);
982 /* If we're just looking for a conflict, we're done. */
984 if (request
->fl_flags
& FL_ACCESS
)
988 * Find the first old lock with the same owner as the new lock.
991 before
= &inode
->i_flock
;
993 /* First skip locks owned by other processes. */
994 while ((fl
= *before
) && (!IS_POSIX(fl
) ||
995 !posix_same_owner(request
, fl
))) {
996 before
= &fl
->fl_next
;
999 /* Process locks with this owner. */
1000 while ((fl
= *before
) && posix_same_owner(request
, fl
)) {
1001 /* Detect adjacent or overlapping regions (if same lock type)
1003 if (request
->fl_type
== fl
->fl_type
) {
1004 /* In all comparisons of start vs end, use
1005 * "start - 1" rather than "end + 1". If end
1006 * is OFFSET_MAX, end + 1 will become negative.
1008 if (fl
->fl_end
< request
->fl_start
- 1)
1010 /* If the next lock in the list has entirely bigger
1011 * addresses than the new one, insert the lock here.
1013 if (fl
->fl_start
- 1 > request
->fl_end
)
1016 /* If we come here, the new and old lock are of the
1017 * same type and adjacent or overlapping. Make one
1018 * lock yielding from the lower start address of both
1019 * locks to the higher end address.
1021 if (fl
->fl_start
> request
->fl_start
)
1022 fl
->fl_start
= request
->fl_start
;
1024 request
->fl_start
= fl
->fl_start
;
1025 if (fl
->fl_end
< request
->fl_end
)
1026 fl
->fl_end
= request
->fl_end
;
1028 request
->fl_end
= fl
->fl_end
;
1030 locks_delete_lock(before
, &dispose
);
1037 /* Processing for different lock types is a bit
1040 if (fl
->fl_end
< request
->fl_start
)
1042 if (fl
->fl_start
> request
->fl_end
)
1044 if (request
->fl_type
== F_UNLCK
)
1046 if (fl
->fl_start
< request
->fl_start
)
1048 /* If the next lock in the list has a higher end
1049 * address than the new one, insert the new one here.
1051 if (fl
->fl_end
> request
->fl_end
) {
1055 if (fl
->fl_start
>= request
->fl_start
) {
1056 /* The new lock completely replaces an old
1057 * one (This may happen several times).
1060 locks_delete_lock(before
, &dispose
);
1064 * Replace the old lock with new_fl, and
1065 * remove the old one. It's safe to do the
1066 * insert here since we know that we won't be
1067 * using new_fl later, and that the lock is
1068 * just replacing an existing lock.
1073 locks_copy_lock(new_fl
, request
);
1076 locks_delete_lock(before
, &dispose
);
1077 locks_insert_lock(before
, request
);
1081 /* Go on to next lock.
1084 before
= &fl
->fl_next
;
1088 * The above code only modifies existing locks in case of merging or
1089 * replacing. If new lock(s) need to be inserted all modifications are
1090 * done below this, so it's safe yet to bail out.
1092 error
= -ENOLCK
; /* "no luck" */
1093 if (right
&& left
== right
&& !new_fl2
)
1098 if (request
->fl_type
== F_UNLCK
) {
1099 if (request
->fl_flags
& FL_EXISTS
)
1108 locks_copy_lock(new_fl
, request
);
1109 locks_insert_lock(before
, new_fl
);
1113 if (left
== right
) {
1114 /* The new lock breaks the old one in two pieces,
1115 * so we have to use the second new lock.
1119 locks_copy_lock(left
, right
);
1120 locks_insert_lock(before
, left
);
1122 right
->fl_start
= request
->fl_end
+ 1;
1123 locks_wake_up_blocks(right
);
1126 left
->fl_end
= request
->fl_start
- 1;
1127 locks_wake_up_blocks(left
);
1130 spin_unlock(&inode
->i_lock
);
1132 * Free any unused locks.
1135 locks_free_lock(new_fl
);
1137 locks_free_lock(new_fl2
);
1138 locks_dispose_list(&dispose
);
1143 * posix_lock_file - Apply a POSIX-style lock to a file
1144 * @filp: The file to apply the lock to
1145 * @fl: The lock to be applied
1146 * @conflock: Place to return a copy of the conflicting lock, if found.
1148 * Add a POSIX style lock to a file.
1149 * We merge adjacent & overlapping locks whenever possible.
1150 * POSIX locks are sorted by owner task, then by starting address
1152 * Note that if called with an FL_EXISTS argument, the caller may determine
1153 * whether or not a lock was successfully freed by testing the return
1154 * value for -ENOENT.
1156 int posix_lock_file(struct file
*filp
, struct file_lock
*fl
,
1157 struct file_lock
*conflock
)
1159 return __posix_lock_file(file_inode(filp
), fl
, conflock
);
1161 EXPORT_SYMBOL(posix_lock_file
);
1164 * posix_lock_file_wait - Apply a POSIX-style lock to a file
1165 * @filp: The file to apply the lock to
1166 * @fl: The lock to be applied
1168 * Add a POSIX style lock to a file.
1169 * We merge adjacent & overlapping locks whenever possible.
1170 * POSIX locks are sorted by owner task, then by starting address
1172 int posix_lock_file_wait(struct file
*filp
, struct file_lock
*fl
)
1177 error
= posix_lock_file(filp
, fl
, NULL
);
1178 if (error
!= FILE_LOCK_DEFERRED
)
1180 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
1184 locks_delete_block(fl
);
1189 EXPORT_SYMBOL(posix_lock_file_wait
);
1192 * locks_mandatory_locked - Check for an active lock
1193 * @file: the file to check
1195 * Searches the inode's list of locks to find any POSIX locks which conflict.
1196 * This function is called from locks_verify_locked() only.
1198 int locks_mandatory_locked(struct file
*file
)
1200 struct inode
*inode
= file_inode(file
);
1201 struct file_lock
*fl
;
1204 * Search the lock list for this inode for any POSIX locks.
1206 spin_lock(&inode
->i_lock
);
1207 for (fl
= inode
->i_flock
; fl
!= NULL
; fl
= fl
->fl_next
) {
1210 if (fl
->fl_owner
!= current
->files
&&
1211 fl
->fl_owner
!= file
)
1214 spin_unlock(&inode
->i_lock
);
1215 return fl
? -EAGAIN
: 0;
1219 * locks_mandatory_area - Check for a conflicting lock
1220 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1222 * @inode: the file to check
1223 * @filp: how the file was opened (if it was)
1224 * @offset: start of area to check
1225 * @count: length of area to check
1227 * Searches the inode's list of locks to find any POSIX locks which conflict.
1228 * This function is called from rw_verify_area() and
1229 * locks_verify_truncate().
1231 int locks_mandatory_area(int read_write
, struct inode
*inode
,
1232 struct file
*filp
, loff_t offset
,
1235 struct file_lock fl
;
1239 locks_init_lock(&fl
);
1240 fl
.fl_pid
= current
->tgid
;
1242 fl
.fl_flags
= FL_POSIX
| FL_ACCESS
;
1243 if (filp
&& !(filp
->f_flags
& O_NONBLOCK
))
1245 fl
.fl_type
= (read_write
== FLOCK_VERIFY_WRITE
) ? F_WRLCK
: F_RDLCK
;
1246 fl
.fl_start
= offset
;
1247 fl
.fl_end
= offset
+ count
- 1;
1252 fl
.fl_flags
&= ~FL_SLEEP
;
1253 error
= __posix_lock_file(inode
, &fl
, NULL
);
1259 fl
.fl_flags
|= FL_SLEEP
;
1260 fl
.fl_owner
= current
->files
;
1261 error
= __posix_lock_file(inode
, &fl
, NULL
);
1262 if (error
!= FILE_LOCK_DEFERRED
)
1264 error
= wait_event_interruptible(fl
.fl_wait
, !fl
.fl_next
);
1267 * If we've been sleeping someone might have
1268 * changed the permissions behind our back.
1270 if (__mandatory_lock(inode
))
1274 locks_delete_block(&fl
);
1281 EXPORT_SYMBOL(locks_mandatory_area
);
1283 static void lease_clear_pending(struct file_lock
*fl
, int arg
)
1287 fl
->fl_flags
&= ~FL_UNLOCK_PENDING
;
1290 fl
->fl_flags
&= ~FL_DOWNGRADE_PENDING
;
1294 /* We already had a lease on this file; just change its type */
1295 int lease_modify(struct file_lock
**before
, int arg
)
1297 struct file_lock
*fl
= *before
;
1298 int error
= assign_type(fl
, arg
);
1302 lease_clear_pending(fl
, arg
);
1303 locks_wake_up_blocks(fl
);
1304 if (arg
== F_UNLCK
) {
1305 struct file
*filp
= fl
->fl_file
;
1308 filp
->f_owner
.signum
= 0;
1309 fasync_helper(0, fl
->fl_file
, 0, &fl
->fl_fasync
);
1310 if (fl
->fl_fasync
!= NULL
) {
1311 printk(KERN_ERR
"locks_delete_lock: fasync == %p\n", fl
->fl_fasync
);
1312 fl
->fl_fasync
= NULL
;
1314 locks_delete_lock(before
, NULL
);
1318 EXPORT_SYMBOL(lease_modify
);
1320 static bool past_time(unsigned long then
)
1323 /* 0 is a special value meaning "this never expires": */
1325 return time_after(jiffies
, then
);
1328 static void time_out_leases(struct inode
*inode
)
1330 struct file_lock
**before
;
1331 struct file_lock
*fl
;
1333 lockdep_assert_held(&inode
->i_lock
);
1335 before
= &inode
->i_flock
;
1336 while ((fl
= *before
) && IS_LEASE(fl
) && lease_breaking(fl
)) {
1337 trace_time_out_leases(inode
, fl
);
1338 if (past_time(fl
->fl_downgrade_time
))
1339 lease_modify(before
, F_RDLCK
);
1340 if (past_time(fl
->fl_break_time
))
1341 lease_modify(before
, F_UNLCK
);
1342 if (fl
== *before
) /* lease_modify may have freed fl */
1343 before
= &fl
->fl_next
;
1347 static bool leases_conflict(struct file_lock
*lease
, struct file_lock
*breaker
)
1349 if ((breaker
->fl_flags
& FL_DELEG
) && (lease
->fl_flags
& FL_LEASE
))
1351 return locks_conflict(breaker
, lease
);
1355 * __break_lease - revoke all outstanding leases on file
1356 * @inode: the inode of the file to return
1357 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1359 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1362 * break_lease (inlined for speed) has checked there already is at least
1363 * some kind of lock (maybe a lease) on this file. Leases are broken on
1364 * a call to open() or truncate(). This function can sleep unless you
1365 * specified %O_NONBLOCK to your open().
1367 int __break_lease(struct inode
*inode
, unsigned int mode
, unsigned int type
)
1370 struct file_lock
*new_fl
, *flock
;
1371 struct file_lock
*fl
;
1372 unsigned long break_time
;
1373 int i_have_this_lease
= 0;
1374 bool lease_conflict
= false;
1375 int want_write
= (mode
& O_ACCMODE
) != O_RDONLY
;
1377 new_fl
= lease_alloc(NULL
, want_write
? F_WRLCK
: F_RDLCK
);
1379 return PTR_ERR(new_fl
);
1380 new_fl
->fl_flags
= type
;
1382 spin_lock(&inode
->i_lock
);
1384 time_out_leases(inode
);
1386 flock
= inode
->i_flock
;
1387 if ((flock
== NULL
) || !IS_LEASE(flock
))
1390 for (fl
= flock
; fl
&& IS_LEASE(fl
); fl
= fl
->fl_next
) {
1391 if (leases_conflict(fl
, new_fl
)) {
1392 lease_conflict
= true;
1393 if (fl
->fl_owner
== current
->files
)
1394 i_have_this_lease
= 1;
1397 if (!lease_conflict
)
1401 if (lease_break_time
> 0) {
1402 break_time
= jiffies
+ lease_break_time
* HZ
;
1403 if (break_time
== 0)
1404 break_time
++; /* so that 0 means no break time */
1407 for (fl
= flock
; fl
&& IS_LEASE(fl
); fl
= fl
->fl_next
) {
1408 if (!leases_conflict(fl
, new_fl
))
1411 if (fl
->fl_flags
& FL_UNLOCK_PENDING
)
1413 fl
->fl_flags
|= FL_UNLOCK_PENDING
;
1414 fl
->fl_break_time
= break_time
;
1416 if (lease_breaking(flock
))
1418 fl
->fl_flags
|= FL_DOWNGRADE_PENDING
;
1419 fl
->fl_downgrade_time
= break_time
;
1421 fl
->fl_lmops
->lm_break(fl
);
1424 if (i_have_this_lease
|| (mode
& O_NONBLOCK
)) {
1425 trace_break_lease_noblock(inode
, new_fl
);
1426 error
= -EWOULDBLOCK
;
1431 break_time
= flock
->fl_break_time
;
1432 if (break_time
!= 0)
1433 break_time
-= jiffies
;
1434 if (break_time
== 0)
1436 locks_insert_block(flock
, new_fl
);
1437 trace_break_lease_block(inode
, new_fl
);
1438 spin_unlock(&inode
->i_lock
);
1439 error
= wait_event_interruptible_timeout(new_fl
->fl_wait
,
1440 !new_fl
->fl_next
, break_time
);
1441 spin_lock(&inode
->i_lock
);
1442 trace_break_lease_unblock(inode
, new_fl
);
1443 locks_delete_block(new_fl
);
1446 time_out_leases(inode
);
1448 * Wait for the next conflicting lease that has not been
1451 for (flock
= inode
->i_flock
; flock
&& IS_LEASE(flock
);
1452 flock
= flock
->fl_next
) {
1453 if (leases_conflict(new_fl
, flock
))
1460 spin_unlock(&inode
->i_lock
);
1461 locks_free_lock(new_fl
);
1465 EXPORT_SYMBOL(__break_lease
);
1468 * lease_get_mtime - get the last modified time of an inode
1470 * @time: pointer to a timespec which will contain the last modified time
1472 * This is to force NFS clients to flush their caches for files with
1473 * exclusive leases. The justification is that if someone has an
1474 * exclusive lease, then they could be modifying it.
1476 void lease_get_mtime(struct inode
*inode
, struct timespec
*time
)
1478 bool has_lease
= false;
1479 struct file_lock
*flock
;
1481 if (inode
->i_flock
) {
1482 spin_lock(&inode
->i_lock
);
1483 flock
= inode
->i_flock
;
1484 if (flock
&& IS_LEASE(flock
) && (flock
->fl_type
== F_WRLCK
))
1486 spin_unlock(&inode
->i_lock
);
1490 *time
= current_fs_time(inode
->i_sb
);
1492 *time
= inode
->i_mtime
;
1495 EXPORT_SYMBOL(lease_get_mtime
);
1498 * fcntl_getlease - Enquire what lease is currently active
1501 * The value returned by this function will be one of
1502 * (if no lease break is pending):
1504 * %F_RDLCK to indicate a shared lease is held.
1506 * %F_WRLCK to indicate an exclusive lease is held.
1508 * %F_UNLCK to indicate no lease is held.
1510 * (if a lease break is pending):
1512 * %F_RDLCK to indicate an exclusive lease needs to be
1513 * changed to a shared lease (or removed).
1515 * %F_UNLCK to indicate the lease needs to be removed.
1517 * XXX: sfr & willy disagree over whether F_INPROGRESS
1518 * should be returned to userspace.
1520 int fcntl_getlease(struct file
*filp
)
1522 struct file_lock
*fl
;
1523 struct inode
*inode
= file_inode(filp
);
1526 spin_lock(&inode
->i_lock
);
1527 time_out_leases(file_inode(filp
));
1528 for (fl
= file_inode(filp
)->i_flock
; fl
&& IS_LEASE(fl
);
1530 if (fl
->fl_file
== filp
) {
1531 type
= target_leasetype(fl
);
1535 spin_unlock(&inode
->i_lock
);
1540 * check_conflicting_open - see if the given dentry points to a file that has
1541 * an existing open that would conflict with the
1543 * @dentry: dentry to check
1544 * @arg: type of lease that we're trying to acquire
1546 * Check to see if there's an existing open fd on this file that would
1547 * conflict with the lease we're trying to set.
1550 check_conflicting_open(const struct dentry
*dentry
, const long arg
)
1553 struct inode
*inode
= dentry
->d_inode
;
1555 if ((arg
== F_RDLCK
) && (atomic_read(&inode
->i_writecount
) > 0))
1558 if ((arg
== F_WRLCK
) && ((d_count(dentry
) > 1) ||
1559 (atomic_read(&inode
->i_count
) > 1)))
1566 generic_add_lease(struct file
*filp
, long arg
, struct file_lock
**flp
, void **priv
)
1568 struct file_lock
*fl
, **before
, **my_before
= NULL
, *lease
;
1569 struct dentry
*dentry
= filp
->f_path
.dentry
;
1570 struct inode
*inode
= dentry
->d_inode
;
1571 bool is_deleg
= (*flp
)->fl_flags
& FL_DELEG
;
1575 trace_generic_add_lease(inode
, lease
);
1578 * In the delegation case we need mutual exclusion with
1579 * a number of operations that take the i_mutex. We trylock
1580 * because delegations are an optional optimization, and if
1581 * there's some chance of a conflict--we'd rather not
1582 * bother, maybe that's a sign this just isn't a good file to
1583 * hand out a delegation on.
1585 if (is_deleg
&& !mutex_trylock(&inode
->i_mutex
))
1588 if (is_deleg
&& arg
== F_WRLCK
) {
1589 /* Write delegations are not currently supported: */
1590 mutex_unlock(&inode
->i_mutex
);
1595 spin_lock(&inode
->i_lock
);
1596 time_out_leases(inode
);
1597 error
= check_conflicting_open(dentry
, arg
);
1602 * At this point, we know that if there is an exclusive
1603 * lease on this file, then we hold it on this filp
1604 * (otherwise our open of this file would have blocked).
1605 * And if we are trying to acquire an exclusive lease,
1606 * then the file is not open by anyone (including us)
1607 * except for this filp.
1610 for (before
= &inode
->i_flock
;
1611 ((fl
= *before
) != NULL
) && IS_LEASE(fl
);
1612 before
= &fl
->fl_next
) {
1613 if (fl
->fl_file
== filp
) {
1618 * No exclusive leases if someone else has a lease on
1624 * Modifying our existing lease is OK, but no getting a
1625 * new lease if someone else is opening for write:
1627 if (fl
->fl_flags
& FL_UNLOCK_PENDING
)
1631 if (my_before
!= NULL
) {
1633 error
= lease
->fl_lmops
->lm_change(my_before
, arg
);
1643 locks_insert_lock(before
, lease
);
1645 * The check in break_lease() is lockless. It's possible for another
1646 * open to race in after we did the earlier check for a conflicting
1647 * open but before the lease was inserted. Check again for a
1648 * conflicting open and cancel the lease if there is one.
1650 * We also add a barrier here to ensure that the insertion of the lock
1651 * precedes these checks.
1654 error
= check_conflicting_open(dentry
, arg
);
1659 if (lease
->fl_lmops
->lm_setup
)
1660 lease
->fl_lmops
->lm_setup(lease
, priv
);
1662 spin_unlock(&inode
->i_lock
);
1664 mutex_unlock(&inode
->i_mutex
);
1665 if (!error
&& !my_before
)
1669 locks_unlink_lock(before
);
1673 static int generic_delete_lease(struct file
*filp
)
1675 int error
= -EAGAIN
;
1676 struct file_lock
*fl
, **before
;
1677 struct dentry
*dentry
= filp
->f_path
.dentry
;
1678 struct inode
*inode
= dentry
->d_inode
;
1680 spin_lock(&inode
->i_lock
);
1681 for (before
= &inode
->i_flock
;
1682 ((fl
= *before
) != NULL
) && IS_LEASE(fl
);
1683 before
= &fl
->fl_next
) {
1684 if (fl
->fl_file
== filp
)
1687 trace_generic_delete_lease(inode
, fl
);
1689 error
= fl
->fl_lmops
->lm_change(before
, F_UNLCK
);
1690 spin_unlock(&inode
->i_lock
);
1695 * generic_setlease - sets a lease on an open file
1696 * @filp: file pointer
1697 * @arg: type of lease to obtain
1698 * @flp: input - file_lock to use, output - file_lock inserted
1699 * @priv: private data for lm_setup (may be NULL if lm_setup
1700 * doesn't require it)
1702 * The (input) flp->fl_lmops->lm_break function is required
1705 int generic_setlease(struct file
*filp
, long arg
, struct file_lock
**flp
,
1708 struct dentry
*dentry
= filp
->f_path
.dentry
;
1709 struct inode
*inode
= dentry
->d_inode
;
1712 if ((!uid_eq(current_fsuid(), inode
->i_uid
)) && !capable(CAP_LEASE
))
1714 if (!S_ISREG(inode
->i_mode
))
1716 error
= security_file_lock(filp
, arg
);
1722 return generic_delete_lease(filp
);
1725 if (!(*flp
)->fl_lmops
->lm_break
) {
1729 return generic_add_lease(filp
, arg
, flp
, priv
);
1734 EXPORT_SYMBOL(generic_setlease
);
1737 * vfs_setlease - sets a lease on an open file
1738 * @filp: file pointer
1739 * @arg: type of lease to obtain
1740 * @lease: file_lock to use when adding a lease
1741 * @priv: private info for lm_setup when adding a lease (may be
1742 * NULL if lm_setup doesn't require it)
1744 * Call this to establish a lease on the file. The "lease" argument is not
1745 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1746 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1747 * if not, this function will return -ENOLCK (and generate a scary-looking
1750 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1751 * may be NULL if the lm_setup operation doesn't require it.
1754 vfs_setlease(struct file
*filp
, long arg
, struct file_lock
**lease
, void **priv
)
1756 if (filp
->f_op
->setlease
)
1757 return filp
->f_op
->setlease(filp
, arg
, lease
, priv
);
1759 return generic_setlease(filp
, arg
, lease
, priv
);
1761 EXPORT_SYMBOL_GPL(vfs_setlease
);
1763 static int do_fcntl_add_lease(unsigned int fd
, struct file
*filp
, long arg
)
1765 struct file_lock
*fl
;
1766 struct fasync_struct
*new;
1769 fl
= lease_alloc(filp
, arg
);
1773 new = fasync_alloc();
1775 locks_free_lock(fl
);
1780 error
= vfs_setlease(filp
, arg
, &fl
, (void **)&new);
1782 locks_free_lock(fl
);
1789 * fcntl_setlease - sets a lease on an open file
1790 * @fd: open file descriptor
1791 * @filp: file pointer
1792 * @arg: type of lease to obtain
1794 * Call this fcntl to establish a lease on the file.
1795 * Note that you also need to call %F_SETSIG to
1796 * receive a signal when the lease is broken.
1798 int fcntl_setlease(unsigned int fd
, struct file
*filp
, long arg
)
1801 return vfs_setlease(filp
, F_UNLCK
, NULL
, NULL
);
1802 return do_fcntl_add_lease(fd
, filp
, arg
);
1806 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1807 * @filp: The file to apply the lock to
1808 * @fl: The lock to be applied
1810 * Add a FLOCK style lock to a file.
1812 int flock_lock_file_wait(struct file
*filp
, struct file_lock
*fl
)
1817 error
= flock_lock_file(filp
, fl
);
1818 if (error
!= FILE_LOCK_DEFERRED
)
1820 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
1824 locks_delete_block(fl
);
1830 EXPORT_SYMBOL(flock_lock_file_wait
);
1833 * sys_flock: - flock() system call.
1834 * @fd: the file descriptor to lock.
1835 * @cmd: the type of lock to apply.
1837 * Apply a %FL_FLOCK style lock to an open file descriptor.
1838 * The @cmd can be one of
1840 * %LOCK_SH -- a shared lock.
1842 * %LOCK_EX -- an exclusive lock.
1844 * %LOCK_UN -- remove an existing lock.
1846 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1848 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1849 * processes read and write access respectively.
1851 SYSCALL_DEFINE2(flock
, unsigned int, fd
, unsigned int, cmd
)
1853 struct fd f
= fdget(fd
);
1854 struct file_lock
*lock
;
1855 int can_sleep
, unlock
;
1862 can_sleep
= !(cmd
& LOCK_NB
);
1864 unlock
= (cmd
== LOCK_UN
);
1866 if (!unlock
&& !(cmd
& LOCK_MAND
) &&
1867 !(f
.file
->f_mode
& (FMODE_READ
|FMODE_WRITE
)))
1870 error
= flock_make_lock(f
.file
, &lock
, cmd
);
1874 lock
->fl_flags
|= FL_SLEEP
;
1876 error
= security_file_lock(f
.file
, lock
->fl_type
);
1880 if (f
.file
->f_op
->flock
)
1881 error
= f
.file
->f_op
->flock(f
.file
,
1882 (can_sleep
) ? F_SETLKW
: F_SETLK
,
1885 error
= flock_lock_file_wait(f
.file
, lock
);
1888 locks_free_lock(lock
);
1897 * vfs_test_lock - test file byte range lock
1898 * @filp: The file to test lock for
1899 * @fl: The lock to test; also used to hold result
1901 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1902 * setting conf->fl_type to something other than F_UNLCK.
1904 int vfs_test_lock(struct file
*filp
, struct file_lock
*fl
)
1906 if (filp
->f_op
->lock
)
1907 return filp
->f_op
->lock(filp
, F_GETLK
, fl
);
1908 posix_test_lock(filp
, fl
);
1911 EXPORT_SYMBOL_GPL(vfs_test_lock
);
1913 static int posix_lock_to_flock(struct flock
*flock
, struct file_lock
*fl
)
1915 flock
->l_pid
= IS_OFDLCK(fl
) ? -1 : fl
->fl_pid
;
1916 #if BITS_PER_LONG == 32
1918 * Make sure we can represent the posix lock via
1919 * legacy 32bit flock.
1921 if (fl
->fl_start
> OFFT_OFFSET_MAX
)
1923 if (fl
->fl_end
!= OFFSET_MAX
&& fl
->fl_end
> OFFT_OFFSET_MAX
)
1926 flock
->l_start
= fl
->fl_start
;
1927 flock
->l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1928 fl
->fl_end
- fl
->fl_start
+ 1;
1929 flock
->l_whence
= 0;
1930 flock
->l_type
= fl
->fl_type
;
1934 #if BITS_PER_LONG == 32
1935 static void posix_lock_to_flock64(struct flock64
*flock
, struct file_lock
*fl
)
1937 flock
->l_pid
= IS_OFDLCK(fl
) ? -1 : fl
->fl_pid
;
1938 flock
->l_start
= fl
->fl_start
;
1939 flock
->l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1940 fl
->fl_end
- fl
->fl_start
+ 1;
1941 flock
->l_whence
= 0;
1942 flock
->l_type
= fl
->fl_type
;
1946 /* Report the first existing lock that would conflict with l.
1947 * This implements the F_GETLK command of fcntl().
1949 int fcntl_getlk(struct file
*filp
, unsigned int cmd
, struct flock __user
*l
)
1951 struct file_lock file_lock
;
1956 if (copy_from_user(&flock
, l
, sizeof(flock
)))
1959 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
1962 error
= flock_to_posix_lock(filp
, &file_lock
, &flock
);
1966 if (cmd
== F_OFD_GETLK
) {
1968 if (flock
.l_pid
!= 0)
1972 file_lock
.fl_flags
|= FL_OFDLCK
;
1973 file_lock
.fl_owner
= filp
;
1976 error
= vfs_test_lock(filp
, &file_lock
);
1980 flock
.l_type
= file_lock
.fl_type
;
1981 if (file_lock
.fl_type
!= F_UNLCK
) {
1982 error
= posix_lock_to_flock(&flock
, &file_lock
);
1987 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
1990 locks_release_private(&file_lock
);
1996 * vfs_lock_file - file byte range lock
1997 * @filp: The file to apply the lock to
1998 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
1999 * @fl: The lock to be applied
2000 * @conf: Place to return a copy of the conflicting lock, if found.
2002 * A caller that doesn't care about the conflicting lock may pass NULL
2003 * as the final argument.
2005 * If the filesystem defines a private ->lock() method, then @conf will
2006 * be left unchanged; so a caller that cares should initialize it to
2007 * some acceptable default.
2009 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2010 * locks, the ->lock() interface may return asynchronously, before the lock has
2011 * been granted or denied by the underlying filesystem, if (and only if)
2012 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2013 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2014 * the request is for a blocking lock. When ->lock() does return asynchronously,
2015 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2016 * request completes.
2017 * If the request is for non-blocking lock the file system should return
2018 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2019 * with the result. If the request timed out the callback routine will return a
2020 * nonzero return code and the file system should release the lock. The file
2021 * system is also responsible to keep a corresponding posix lock when it
2022 * grants a lock so the VFS can find out which locks are locally held and do
2023 * the correct lock cleanup when required.
2024 * The underlying filesystem must not drop the kernel lock or call
2025 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2028 int vfs_lock_file(struct file
*filp
, unsigned int cmd
, struct file_lock
*fl
, struct file_lock
*conf
)
2030 if (filp
->f_op
->lock
)
2031 return filp
->f_op
->lock(filp
, cmd
, fl
);
2033 return posix_lock_file(filp
, fl
, conf
);
2035 EXPORT_SYMBOL_GPL(vfs_lock_file
);
2037 static int do_lock_file_wait(struct file
*filp
, unsigned int cmd
,
2038 struct file_lock
*fl
)
2042 error
= security_file_lock(filp
, fl
->fl_type
);
2047 error
= vfs_lock_file(filp
, cmd
, fl
, NULL
);
2048 if (error
!= FILE_LOCK_DEFERRED
)
2050 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
2054 locks_delete_block(fl
);
2061 /* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
2063 check_fmode_for_setlk(struct file_lock
*fl
)
2065 switch (fl
->fl_type
) {
2067 if (!(fl
->fl_file
->f_mode
& FMODE_READ
))
2071 if (!(fl
->fl_file
->f_mode
& FMODE_WRITE
))
2077 /* Apply the lock described by l to an open file descriptor.
2078 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2080 int fcntl_setlk(unsigned int fd
, struct file
*filp
, unsigned int cmd
,
2081 struct flock __user
*l
)
2083 struct file_lock
*file_lock
= locks_alloc_lock();
2085 struct inode
*inode
;
2089 if (file_lock
== NULL
)
2093 * This might block, so we do it before checking the inode.
2096 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2099 inode
= file_inode(filp
);
2101 /* Don't allow mandatory locks on files that may be memory mapped
2104 if (mandatory_lock(inode
) && mapping_writably_mapped(filp
->f_mapping
)) {
2110 error
= flock_to_posix_lock(filp
, file_lock
, &flock
);
2114 error
= check_fmode_for_setlk(file_lock
);
2119 * If the cmd is requesting file-private locks, then set the
2120 * FL_OFDLCK flag and override the owner.
2125 if (flock
.l_pid
!= 0)
2129 file_lock
->fl_flags
|= FL_OFDLCK
;
2130 file_lock
->fl_owner
= filp
;
2134 if (flock
.l_pid
!= 0)
2138 file_lock
->fl_flags
|= FL_OFDLCK
;
2139 file_lock
->fl_owner
= filp
;
2142 file_lock
->fl_flags
|= FL_SLEEP
;
2145 error
= do_lock_file_wait(filp
, cmd
, file_lock
);
2148 * Attempt to detect a close/fcntl race and recover by
2149 * releasing the lock that was just acquired.
2152 * we need that spin_lock here - it prevents reordering between
2153 * update of inode->i_flock and check for it done in close().
2154 * rcu_read_lock() wouldn't do.
2156 spin_lock(¤t
->files
->file_lock
);
2158 spin_unlock(¤t
->files
->file_lock
);
2159 if (!error
&& f
!= filp
&& flock
.l_type
!= F_UNLCK
) {
2160 flock
.l_type
= F_UNLCK
;
2165 locks_free_lock(file_lock
);
2169 #if BITS_PER_LONG == 32
2170 /* Report the first existing lock that would conflict with l.
2171 * This implements the F_GETLK command of fcntl().
2173 int fcntl_getlk64(struct file
*filp
, unsigned int cmd
, struct flock64 __user
*l
)
2175 struct file_lock file_lock
;
2176 struct flock64 flock
;
2180 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2183 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
2186 error
= flock64_to_posix_lock(filp
, &file_lock
, &flock
);
2190 if (cmd
== F_OFD_GETLK
) {
2192 if (flock
.l_pid
!= 0)
2196 file_lock
.fl_flags
|= FL_OFDLCK
;
2197 file_lock
.fl_owner
= filp
;
2200 error
= vfs_test_lock(filp
, &file_lock
);
2204 flock
.l_type
= file_lock
.fl_type
;
2205 if (file_lock
.fl_type
!= F_UNLCK
)
2206 posix_lock_to_flock64(&flock
, &file_lock
);
2209 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
2212 locks_release_private(&file_lock
);
2217 /* Apply the lock described by l to an open file descriptor.
2218 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2220 int fcntl_setlk64(unsigned int fd
, struct file
*filp
, unsigned int cmd
,
2221 struct flock64 __user
*l
)
2223 struct file_lock
*file_lock
= locks_alloc_lock();
2224 struct flock64 flock
;
2225 struct inode
*inode
;
2229 if (file_lock
== NULL
)
2233 * This might block, so we do it before checking the inode.
2236 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2239 inode
= file_inode(filp
);
2241 /* Don't allow mandatory locks on files that may be memory mapped
2244 if (mandatory_lock(inode
) && mapping_writably_mapped(filp
->f_mapping
)) {
2250 error
= flock64_to_posix_lock(filp
, file_lock
, &flock
);
2254 error
= check_fmode_for_setlk(file_lock
);
2259 * If the cmd is requesting file-private locks, then set the
2260 * FL_OFDLCK flag and override the owner.
2265 if (flock
.l_pid
!= 0)
2269 file_lock
->fl_flags
|= FL_OFDLCK
;
2270 file_lock
->fl_owner
= filp
;
2274 if (flock
.l_pid
!= 0)
2278 file_lock
->fl_flags
|= FL_OFDLCK
;
2279 file_lock
->fl_owner
= filp
;
2282 file_lock
->fl_flags
|= FL_SLEEP
;
2285 error
= do_lock_file_wait(filp
, cmd
, file_lock
);
2288 * Attempt to detect a close/fcntl race and recover by
2289 * releasing the lock that was just acquired.
2291 spin_lock(¤t
->files
->file_lock
);
2293 spin_unlock(¤t
->files
->file_lock
);
2294 if (!error
&& f
!= filp
&& flock
.l_type
!= F_UNLCK
) {
2295 flock
.l_type
= F_UNLCK
;
2300 locks_free_lock(file_lock
);
2303 #endif /* BITS_PER_LONG == 32 */
2306 * This function is called when the file is being removed
2307 * from the task's fd array. POSIX locks belonging to this task
2308 * are deleted at this time.
2310 void locks_remove_posix(struct file
*filp
, fl_owner_t owner
)
2312 struct file_lock lock
;
2315 * If there are no locks held on this file, we don't need to call
2316 * posix_lock_file(). Another process could be setting a lock on this
2317 * file at the same time, but we wouldn't remove that lock anyway.
2319 if (!file_inode(filp
)->i_flock
)
2322 lock
.fl_type
= F_UNLCK
;
2323 lock
.fl_flags
= FL_POSIX
| FL_CLOSE
;
2325 lock
.fl_end
= OFFSET_MAX
;
2326 lock
.fl_owner
= owner
;
2327 lock
.fl_pid
= current
->tgid
;
2328 lock
.fl_file
= filp
;
2330 lock
.fl_lmops
= NULL
;
2332 vfs_lock_file(filp
, F_SETLK
, &lock
, NULL
);
2334 if (lock
.fl_ops
&& lock
.fl_ops
->fl_release_private
)
2335 lock
.fl_ops
->fl_release_private(&lock
);
2338 EXPORT_SYMBOL(locks_remove_posix
);
2341 * This function is called on the last close of an open file.
2343 void locks_remove_file(struct file
*filp
)
2345 struct inode
* inode
= file_inode(filp
);
2346 struct file_lock
*fl
;
2347 struct file_lock
**before
;
2350 if (!inode
->i_flock
)
2353 locks_remove_posix(filp
, filp
);
2355 if (filp
->f_op
->flock
) {
2356 struct file_lock fl
= {
2358 .fl_pid
= current
->tgid
,
2360 .fl_flags
= FL_FLOCK
,
2362 .fl_end
= OFFSET_MAX
,
2364 filp
->f_op
->flock(filp
, F_SETLKW
, &fl
);
2365 if (fl
.fl_ops
&& fl
.fl_ops
->fl_release_private
)
2366 fl
.fl_ops
->fl_release_private(&fl
);
2369 spin_lock(&inode
->i_lock
);
2370 before
= &inode
->i_flock
;
2372 while ((fl
= *before
) != NULL
) {
2373 if (fl
->fl_file
== filp
) {
2375 lease_modify(before
, F_UNLCK
);
2380 * There's a leftover lock on the list of a type that
2381 * we didn't expect to see. Most likely a classic
2382 * POSIX lock that ended up not getting released
2383 * properly, or that raced onto the list somehow. Log
2384 * some info about it and then just remove it from
2388 "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n",
2389 MAJOR(inode
->i_sb
->s_dev
),
2390 MINOR(inode
->i_sb
->s_dev
), inode
->i_ino
,
2391 fl
->fl_type
, fl
->fl_flags
,
2392 fl
->fl_start
, fl
->fl_end
);
2394 locks_delete_lock(before
, &dispose
);
2397 before
= &fl
->fl_next
;
2399 spin_unlock(&inode
->i_lock
);
2400 locks_dispose_list(&dispose
);
2404 * posix_unblock_lock - stop waiting for a file lock
2405 * @waiter: the lock which was waiting
2407 * lockd needs to block waiting for locks.
2410 posix_unblock_lock(struct file_lock
*waiter
)
2414 spin_lock(&blocked_lock_lock
);
2415 if (waiter
->fl_next
)
2416 __locks_delete_block(waiter
);
2419 spin_unlock(&blocked_lock_lock
);
2422 EXPORT_SYMBOL(posix_unblock_lock
);
2425 * vfs_cancel_lock - file byte range unblock lock
2426 * @filp: The file to apply the unblock to
2427 * @fl: The lock to be unblocked
2429 * Used by lock managers to cancel blocked requests
2431 int vfs_cancel_lock(struct file
*filp
, struct file_lock
*fl
)
2433 if (filp
->f_op
->lock
)
2434 return filp
->f_op
->lock(filp
, F_CANCELLK
, fl
);
2438 EXPORT_SYMBOL_GPL(vfs_cancel_lock
);
2440 #ifdef CONFIG_PROC_FS
2441 #include <linux/proc_fs.h>
2442 #include <linux/seq_file.h>
2444 struct locks_iterator
{
2449 static void lock_get_status(struct seq_file
*f
, struct file_lock
*fl
,
2450 loff_t id
, char *pfx
)
2452 struct inode
*inode
= NULL
;
2453 unsigned int fl_pid
;
2456 fl_pid
= pid_vnr(fl
->fl_nspid
);
2458 fl_pid
= fl
->fl_pid
;
2460 if (fl
->fl_file
!= NULL
)
2461 inode
= file_inode(fl
->fl_file
);
2463 seq_printf(f
, "%lld:%s ", id
, pfx
);
2465 if (fl
->fl_flags
& FL_ACCESS
)
2466 seq_puts(f
, "ACCESS");
2467 else if (IS_OFDLCK(fl
))
2468 seq_puts(f
, "OFDLCK");
2470 seq_puts(f
, "POSIX ");
2472 seq_printf(f
, " %s ",
2473 (inode
== NULL
) ? "*NOINODE*" :
2474 mandatory_lock(inode
) ? "MANDATORY" : "ADVISORY ");
2475 } else if (IS_FLOCK(fl
)) {
2476 if (fl
->fl_type
& LOCK_MAND
) {
2477 seq_puts(f
, "FLOCK MSNFS ");
2479 seq_puts(f
, "FLOCK ADVISORY ");
2481 } else if (IS_LEASE(fl
)) {
2482 if (fl
->fl_flags
& FL_DELEG
)
2483 seq_puts(f
, "DELEG ");
2485 seq_puts(f
, "LEASE ");
2487 if (lease_breaking(fl
))
2488 seq_puts(f
, "BREAKING ");
2489 else if (fl
->fl_file
)
2490 seq_puts(f
, "ACTIVE ");
2492 seq_puts(f
, "BREAKER ");
2494 seq_puts(f
, "UNKNOWN UNKNOWN ");
2496 if (fl
->fl_type
& LOCK_MAND
) {
2497 seq_printf(f
, "%s ",
2498 (fl
->fl_type
& LOCK_READ
)
2499 ? (fl
->fl_type
& LOCK_WRITE
) ? "RW " : "READ "
2500 : (fl
->fl_type
& LOCK_WRITE
) ? "WRITE" : "NONE ");
2502 seq_printf(f
, "%s ",
2503 (lease_breaking(fl
))
2504 ? (fl
->fl_type
== F_UNLCK
) ? "UNLCK" : "READ "
2505 : (fl
->fl_type
== F_WRLCK
) ? "WRITE" : "READ ");
2508 #ifdef WE_CAN_BREAK_LSLK_NOW
2509 seq_printf(f
, "%d %s:%ld ", fl_pid
,
2510 inode
->i_sb
->s_id
, inode
->i_ino
);
2512 /* userspace relies on this representation of dev_t ;-( */
2513 seq_printf(f
, "%d %02x:%02x:%ld ", fl_pid
,
2514 MAJOR(inode
->i_sb
->s_dev
),
2515 MINOR(inode
->i_sb
->s_dev
), inode
->i_ino
);
2518 seq_printf(f
, "%d <none>:0 ", fl_pid
);
2521 if (fl
->fl_end
== OFFSET_MAX
)
2522 seq_printf(f
, "%Ld EOF\n", fl
->fl_start
);
2524 seq_printf(f
, "%Ld %Ld\n", fl
->fl_start
, fl
->fl_end
);
2526 seq_puts(f
, "0 EOF\n");
2530 static int locks_show(struct seq_file
*f
, void *v
)
2532 struct locks_iterator
*iter
= f
->private;
2533 struct file_lock
*fl
, *bfl
;
2535 fl
= hlist_entry(v
, struct file_lock
, fl_link
);
2537 lock_get_status(f
, fl
, iter
->li_pos
, "");
2539 list_for_each_entry(bfl
, &fl
->fl_block
, fl_block
)
2540 lock_get_status(f
, bfl
, iter
->li_pos
, " ->");
2545 static void *locks_start(struct seq_file
*f
, loff_t
*pos
)
2546 __acquires(&blocked_lock_lock
)
2548 struct locks_iterator
*iter
= f
->private;
2550 iter
->li_pos
= *pos
+ 1;
2551 lg_global_lock(&file_lock_lglock
);
2552 spin_lock(&blocked_lock_lock
);
2553 return seq_hlist_start_percpu(&file_lock_list
, &iter
->li_cpu
, *pos
);
2556 static void *locks_next(struct seq_file
*f
, void *v
, loff_t
*pos
)
2558 struct locks_iterator
*iter
= f
->private;
2561 return seq_hlist_next_percpu(v
, &file_lock_list
, &iter
->li_cpu
, pos
);
2564 static void locks_stop(struct seq_file
*f
, void *v
)
2565 __releases(&blocked_lock_lock
)
2567 spin_unlock(&blocked_lock_lock
);
2568 lg_global_unlock(&file_lock_lglock
);
2571 static const struct seq_operations locks_seq_operations
= {
2572 .start
= locks_start
,
2578 static int locks_open(struct inode
*inode
, struct file
*filp
)
2580 return seq_open_private(filp
, &locks_seq_operations
,
2581 sizeof(struct locks_iterator
));
2584 static const struct file_operations proc_locks_operations
= {
2587 .llseek
= seq_lseek
,
2588 .release
= seq_release_private
,
2591 static int __init
proc_locks_init(void)
2593 proc_create("locks", 0, NULL
, &proc_locks_operations
);
2596 module_init(proc_locks_init
);
2599 static int __init
filelock_init(void)
2603 filelock_cache
= kmem_cache_create("file_lock_cache",
2604 sizeof(struct file_lock
), 0, SLAB_PANIC
, NULL
);
2606 lg_lock_init(&file_lock_lglock
, "file_lock_lglock");
2608 for_each_possible_cpu(i
)
2609 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list
, i
));
2614 core_initcall(filelock_init
);