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|FL_LAYOUT))
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;
161 * The global file_lock_list is only used for displaying /proc/locks, so we
162 * keep a list on each CPU, with each list protected by its own spinlock via
163 * the file_lock_lglock. Note that alterations to the list also require that
164 * the relevant flc_lock is held.
166 DEFINE_STATIC_LGLOCK(file_lock_lglock
);
167 static DEFINE_PER_CPU(struct hlist_head
, file_lock_list
);
170 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
171 * It is protected by blocked_lock_lock.
173 * We hash locks by lockowner in order to optimize searching for the lock a
174 * particular lockowner is waiting on.
176 * FIXME: make this value scale via some heuristic? We generally will want more
177 * buckets when we have more lockowners holding locks, but that's a little
178 * difficult to determine without knowing what the workload will look like.
180 #define BLOCKED_HASH_BITS 7
181 static DEFINE_HASHTABLE(blocked_hash
, BLOCKED_HASH_BITS
);
184 * This lock protects the blocked_hash. Generally, if you're accessing it, you
185 * want to be holding this lock.
187 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
188 * pointer for file_lock structures that are acting as lock requests (in
189 * contrast to those that are acting as records of acquired locks).
191 * Note that when we acquire this lock in order to change the above fields,
192 * we often hold the flc_lock as well. In certain cases, when reading the fields
193 * protected by this lock, we can skip acquiring it iff we already hold the
196 * In particular, adding an entry to the fl_block list requires that you hold
197 * both the flc_lock and the blocked_lock_lock (acquired in that order).
198 * Deleting an entry from the list however only requires the file_lock_lock.
200 static DEFINE_SPINLOCK(blocked_lock_lock
);
202 static struct kmem_cache
*flctx_cache __read_mostly
;
203 static struct kmem_cache
*filelock_cache __read_mostly
;
205 static struct file_lock_context
*
206 locks_get_lock_context(struct inode
*inode
)
208 struct file_lock_context
*new;
210 if (likely(inode
->i_flctx
))
213 new = kmem_cache_alloc(flctx_cache
, GFP_KERNEL
);
217 spin_lock_init(&new->flc_lock
);
218 INIT_LIST_HEAD(&new->flc_flock
);
219 INIT_LIST_HEAD(&new->flc_posix
);
220 INIT_LIST_HEAD(&new->flc_lease
);
223 * Assign the pointer if it's not already assigned. If it is, then
224 * free the context we just allocated.
226 spin_lock(&inode
->i_lock
);
227 if (likely(!inode
->i_flctx
)) {
228 inode
->i_flctx
= new;
231 spin_unlock(&inode
->i_lock
);
234 kmem_cache_free(flctx_cache
, new);
236 return inode
->i_flctx
;
240 locks_free_lock_context(struct file_lock_context
*ctx
)
243 WARN_ON_ONCE(!list_empty(&ctx
->flc_flock
));
244 WARN_ON_ONCE(!list_empty(&ctx
->flc_posix
));
245 WARN_ON_ONCE(!list_empty(&ctx
->flc_lease
));
246 kmem_cache_free(flctx_cache
, ctx
);
250 static void locks_init_lock_heads(struct file_lock
*fl
)
252 INIT_HLIST_NODE(&fl
->fl_link
);
253 INIT_LIST_HEAD(&fl
->fl_list
);
254 INIT_LIST_HEAD(&fl
->fl_block
);
255 init_waitqueue_head(&fl
->fl_wait
);
258 /* Allocate an empty lock structure. */
259 struct file_lock
*locks_alloc_lock(void)
261 struct file_lock
*fl
= kmem_cache_zalloc(filelock_cache
, GFP_KERNEL
);
264 locks_init_lock_heads(fl
);
268 EXPORT_SYMBOL_GPL(locks_alloc_lock
);
270 void locks_release_private(struct file_lock
*fl
)
273 if (fl
->fl_ops
->fl_release_private
)
274 fl
->fl_ops
->fl_release_private(fl
);
279 if (fl
->fl_lmops
->lm_put_owner
)
280 fl
->fl_lmops
->lm_put_owner(fl
);
284 EXPORT_SYMBOL_GPL(locks_release_private
);
286 /* Free a lock which is not in use. */
287 void locks_free_lock(struct file_lock
*fl
)
289 BUG_ON(waitqueue_active(&fl
->fl_wait
));
290 BUG_ON(!list_empty(&fl
->fl_list
));
291 BUG_ON(!list_empty(&fl
->fl_block
));
292 BUG_ON(!hlist_unhashed(&fl
->fl_link
));
294 locks_release_private(fl
);
295 kmem_cache_free(filelock_cache
, fl
);
297 EXPORT_SYMBOL(locks_free_lock
);
300 locks_dispose_list(struct list_head
*dispose
)
302 struct file_lock
*fl
;
304 while (!list_empty(dispose
)) {
305 fl
= list_first_entry(dispose
, struct file_lock
, fl_list
);
306 list_del_init(&fl
->fl_list
);
311 void locks_init_lock(struct file_lock
*fl
)
313 memset(fl
, 0, sizeof(struct file_lock
));
314 locks_init_lock_heads(fl
);
317 EXPORT_SYMBOL(locks_init_lock
);
320 * Initialize a new lock from an existing file_lock structure.
322 void locks_copy_conflock(struct file_lock
*new, struct file_lock
*fl
)
324 new->fl_owner
= fl
->fl_owner
;
325 new->fl_pid
= fl
->fl_pid
;
327 new->fl_flags
= fl
->fl_flags
;
328 new->fl_type
= fl
->fl_type
;
329 new->fl_start
= fl
->fl_start
;
330 new->fl_end
= fl
->fl_end
;
331 new->fl_lmops
= fl
->fl_lmops
;
335 if (fl
->fl_lmops
->lm_get_owner
)
336 fl
->fl_lmops
->lm_get_owner(new, fl
);
339 EXPORT_SYMBOL(locks_copy_conflock
);
341 void locks_copy_lock(struct file_lock
*new, struct file_lock
*fl
)
343 /* "new" must be a freshly-initialized lock */
344 WARN_ON_ONCE(new->fl_ops
);
346 locks_copy_conflock(new, fl
);
348 new->fl_file
= fl
->fl_file
;
349 new->fl_ops
= fl
->fl_ops
;
352 if (fl
->fl_ops
->fl_copy_lock
)
353 fl
->fl_ops
->fl_copy_lock(new, fl
);
357 EXPORT_SYMBOL(locks_copy_lock
);
359 static inline int flock_translate_cmd(int cmd
) {
361 return cmd
& (LOCK_MAND
| LOCK_RW
);
373 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
374 static struct file_lock
*
375 flock_make_lock(struct file
*filp
, unsigned int cmd
)
377 struct file_lock
*fl
;
378 int type
= flock_translate_cmd(cmd
);
381 return ERR_PTR(type
);
383 fl
= locks_alloc_lock();
385 return ERR_PTR(-ENOMEM
);
389 fl
->fl_pid
= current
->tgid
;
390 fl
->fl_flags
= FL_FLOCK
;
392 fl
->fl_end
= OFFSET_MAX
;
397 static int assign_type(struct file_lock
*fl
, long type
)
411 static int flock64_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
414 switch (l
->l_whence
) {
419 fl
->fl_start
= filp
->f_pos
;
422 fl
->fl_start
= i_size_read(file_inode(filp
));
427 if (l
->l_start
> OFFSET_MAX
- fl
->fl_start
)
429 fl
->fl_start
+= l
->l_start
;
430 if (fl
->fl_start
< 0)
433 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
434 POSIX-2001 defines it. */
436 if (l
->l_len
- 1 > OFFSET_MAX
- fl
->fl_start
)
438 fl
->fl_end
= fl
->fl_start
+ l
->l_len
- 1;
440 } else if (l
->l_len
< 0) {
441 if (fl
->fl_start
+ l
->l_len
< 0)
443 fl
->fl_end
= fl
->fl_start
- 1;
444 fl
->fl_start
+= l
->l_len
;
446 fl
->fl_end
= OFFSET_MAX
;
448 fl
->fl_owner
= current
->files
;
449 fl
->fl_pid
= current
->tgid
;
451 fl
->fl_flags
= FL_POSIX
;
455 return assign_type(fl
, l
->l_type
);
458 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
461 static int flock_to_posix_lock(struct file
*filp
, struct file_lock
*fl
,
464 struct flock64 ll
= {
466 .l_whence
= l
->l_whence
,
467 .l_start
= l
->l_start
,
471 return flock64_to_posix_lock(filp
, fl
, &ll
);
474 /* default lease lock manager operations */
476 lease_break_callback(struct file_lock
*fl
)
478 kill_fasync(&fl
->fl_fasync
, SIGIO
, POLL_MSG
);
483 lease_setup(struct file_lock
*fl
, void **priv
)
485 struct file
*filp
= fl
->fl_file
;
486 struct fasync_struct
*fa
= *priv
;
489 * fasync_insert_entry() returns the old entry if any. If there was no
490 * old entry, then it used "priv" and inserted it into the fasync list.
491 * Clear the pointer to indicate that it shouldn't be freed.
493 if (!fasync_insert_entry(fa
->fa_fd
, filp
, &fl
->fl_fasync
, fa
))
496 __f_setown(filp
, task_pid(current
), PIDTYPE_PID
, 0);
499 static const struct lock_manager_operations lease_manager_ops
= {
500 .lm_break
= lease_break_callback
,
501 .lm_change
= lease_modify
,
502 .lm_setup
= lease_setup
,
506 * Initialize a lease, use the default lock manager operations
508 static int lease_init(struct file
*filp
, long type
, struct file_lock
*fl
)
510 if (assign_type(fl
, type
) != 0)
514 fl
->fl_pid
= current
->tgid
;
517 fl
->fl_flags
= FL_LEASE
;
519 fl
->fl_end
= OFFSET_MAX
;
521 fl
->fl_lmops
= &lease_manager_ops
;
525 /* Allocate a file_lock initialised to this type of lease */
526 static struct file_lock
*lease_alloc(struct file
*filp
, long type
)
528 struct file_lock
*fl
= locks_alloc_lock();
532 return ERR_PTR(error
);
534 error
= lease_init(filp
, type
, fl
);
537 return ERR_PTR(error
);
542 /* Check if two locks overlap each other.
544 static inline int locks_overlap(struct file_lock
*fl1
, struct file_lock
*fl2
)
546 return ((fl1
->fl_end
>= fl2
->fl_start
) &&
547 (fl2
->fl_end
>= fl1
->fl_start
));
551 * Check whether two locks have the same owner.
553 static int posix_same_owner(struct file_lock
*fl1
, struct file_lock
*fl2
)
555 if (fl1
->fl_lmops
&& fl1
->fl_lmops
->lm_compare_owner
)
556 return fl2
->fl_lmops
== fl1
->fl_lmops
&&
557 fl1
->fl_lmops
->lm_compare_owner(fl1
, fl2
);
558 return fl1
->fl_owner
== fl2
->fl_owner
;
561 /* Must be called with the flc_lock held! */
562 static void locks_insert_global_locks(struct file_lock
*fl
)
564 lg_local_lock(&file_lock_lglock
);
565 fl
->fl_link_cpu
= smp_processor_id();
566 hlist_add_head(&fl
->fl_link
, this_cpu_ptr(&file_lock_list
));
567 lg_local_unlock(&file_lock_lglock
);
570 /* Must be called with the flc_lock held! */
571 static void locks_delete_global_locks(struct file_lock
*fl
)
574 * Avoid taking lock if already unhashed. This is safe since this check
575 * is done while holding the flc_lock, and new insertions into the list
576 * also require that it be held.
578 if (hlist_unhashed(&fl
->fl_link
))
580 lg_local_lock_cpu(&file_lock_lglock
, fl
->fl_link_cpu
);
581 hlist_del_init(&fl
->fl_link
);
582 lg_local_unlock_cpu(&file_lock_lglock
, fl
->fl_link_cpu
);
586 posix_owner_key(struct file_lock
*fl
)
588 if (fl
->fl_lmops
&& fl
->fl_lmops
->lm_owner_key
)
589 return fl
->fl_lmops
->lm_owner_key(fl
);
590 return (unsigned long)fl
->fl_owner
;
593 static void locks_insert_global_blocked(struct file_lock
*waiter
)
595 hash_add(blocked_hash
, &waiter
->fl_link
, posix_owner_key(waiter
));
598 static void locks_delete_global_blocked(struct file_lock
*waiter
)
600 hash_del(&waiter
->fl_link
);
603 /* Remove waiter from blocker's block list.
604 * When blocker ends up pointing to itself then the list is empty.
606 * Must be called with blocked_lock_lock held.
608 static void __locks_delete_block(struct file_lock
*waiter
)
610 locks_delete_global_blocked(waiter
);
611 list_del_init(&waiter
->fl_block
);
612 waiter
->fl_next
= NULL
;
615 static void locks_delete_block(struct file_lock
*waiter
)
617 spin_lock(&blocked_lock_lock
);
618 __locks_delete_block(waiter
);
619 spin_unlock(&blocked_lock_lock
);
622 /* Insert waiter into blocker's block list.
623 * We use a circular list so that processes can be easily woken up in
624 * the order they blocked. The documentation doesn't require this but
625 * it seems like the reasonable thing to do.
627 * Must be called with both the flc_lock and blocked_lock_lock held. The
628 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
629 * that the flc_lock is also held on insertions we can avoid taking the
630 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
632 static void __locks_insert_block(struct file_lock
*blocker
,
633 struct file_lock
*waiter
)
635 BUG_ON(!list_empty(&waiter
->fl_block
));
636 waiter
->fl_next
= blocker
;
637 list_add_tail(&waiter
->fl_block
, &blocker
->fl_block
);
638 if (IS_POSIX(blocker
) && !IS_OFDLCK(blocker
))
639 locks_insert_global_blocked(waiter
);
642 /* Must be called with flc_lock held. */
643 static void locks_insert_block(struct file_lock
*blocker
,
644 struct file_lock
*waiter
)
646 spin_lock(&blocked_lock_lock
);
647 __locks_insert_block(blocker
, waiter
);
648 spin_unlock(&blocked_lock_lock
);
652 * Wake up processes blocked waiting for blocker.
654 * Must be called with the inode->flc_lock held!
656 static void locks_wake_up_blocks(struct file_lock
*blocker
)
659 * Avoid taking global lock if list is empty. This is safe since new
660 * blocked requests are only added to the list under the flc_lock, and
661 * the flc_lock is always held here. Note that removal from the fl_block
662 * list does not require the flc_lock, so we must recheck list_empty()
663 * after acquiring the blocked_lock_lock.
665 if (list_empty(&blocker
->fl_block
))
668 spin_lock(&blocked_lock_lock
);
669 while (!list_empty(&blocker
->fl_block
)) {
670 struct file_lock
*waiter
;
672 waiter
= list_first_entry(&blocker
->fl_block
,
673 struct file_lock
, fl_block
);
674 __locks_delete_block(waiter
);
675 if (waiter
->fl_lmops
&& waiter
->fl_lmops
->lm_notify
)
676 waiter
->fl_lmops
->lm_notify(waiter
);
678 wake_up(&waiter
->fl_wait
);
680 spin_unlock(&blocked_lock_lock
);
684 locks_insert_lock_ctx(struct file_lock
*fl
, struct list_head
*before
)
686 fl
->fl_nspid
= get_pid(task_tgid(current
));
687 list_add_tail(&fl
->fl_list
, before
);
688 locks_insert_global_locks(fl
);
692 locks_unlink_lock_ctx(struct file_lock
*fl
)
694 locks_delete_global_locks(fl
);
695 list_del_init(&fl
->fl_list
);
697 put_pid(fl
->fl_nspid
);
700 locks_wake_up_blocks(fl
);
704 locks_delete_lock_ctx(struct file_lock
*fl
, struct list_head
*dispose
)
706 locks_unlink_lock_ctx(fl
);
708 list_add(&fl
->fl_list
, dispose
);
713 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
714 * checks for shared/exclusive status of overlapping locks.
716 static int locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
718 if (sys_fl
->fl_type
== F_WRLCK
)
720 if (caller_fl
->fl_type
== F_WRLCK
)
725 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
726 * checking before calling the locks_conflict().
728 static int posix_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
730 /* POSIX locks owned by the same process do not conflict with
733 if (!IS_POSIX(sys_fl
) || posix_same_owner(caller_fl
, sys_fl
))
736 /* Check whether they overlap */
737 if (!locks_overlap(caller_fl
, sys_fl
))
740 return (locks_conflict(caller_fl
, sys_fl
));
743 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
744 * checking before calling the locks_conflict().
746 static int flock_locks_conflict(struct file_lock
*caller_fl
, struct file_lock
*sys_fl
)
748 /* FLOCK locks referring to the same filp do not conflict with
751 if (!IS_FLOCK(sys_fl
) || (caller_fl
->fl_file
== sys_fl
->fl_file
))
753 if ((caller_fl
->fl_type
& LOCK_MAND
) || (sys_fl
->fl_type
& LOCK_MAND
))
756 return (locks_conflict(caller_fl
, sys_fl
));
760 posix_test_lock(struct file
*filp
, struct file_lock
*fl
)
762 struct file_lock
*cfl
;
763 struct file_lock_context
*ctx
;
764 struct inode
*inode
= file_inode(filp
);
766 ctx
= inode
->i_flctx
;
767 if (!ctx
|| list_empty_careful(&ctx
->flc_posix
)) {
768 fl
->fl_type
= F_UNLCK
;
772 spin_lock(&ctx
->flc_lock
);
773 list_for_each_entry(cfl
, &ctx
->flc_posix
, fl_list
) {
774 if (posix_locks_conflict(fl
, cfl
)) {
775 locks_copy_conflock(fl
, cfl
);
777 fl
->fl_pid
= pid_vnr(cfl
->fl_nspid
);
781 fl
->fl_type
= F_UNLCK
;
783 spin_unlock(&ctx
->flc_lock
);
786 EXPORT_SYMBOL(posix_test_lock
);
789 * Deadlock detection:
791 * We attempt to detect deadlocks that are due purely to posix file
794 * We assume that a task can be waiting for at most one lock at a time.
795 * So for any acquired lock, the process holding that lock may be
796 * waiting on at most one other lock. That lock in turns may be held by
797 * someone waiting for at most one other lock. Given a requested lock
798 * caller_fl which is about to wait for a conflicting lock block_fl, we
799 * follow this chain of waiters to ensure we are not about to create a
802 * Since we do this before we ever put a process to sleep on a lock, we
803 * are ensured that there is never a cycle; that is what guarantees that
804 * the while() loop in posix_locks_deadlock() eventually completes.
806 * Note: the above assumption may not be true when handling lock
807 * requests from a broken NFS client. It may also fail in the presence
808 * of tasks (such as posix threads) sharing the same open file table.
809 * To handle those cases, we just bail out after a few iterations.
811 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
812 * Because the owner is not even nominally tied to a thread of
813 * execution, the deadlock detection below can't reasonably work well. Just
816 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
817 * locks that just checks for the case where two tasks are attempting to
818 * upgrade from read to write locks on the same inode.
821 #define MAX_DEADLK_ITERATIONS 10
823 /* Find a lock that the owner of the given block_fl is blocking on. */
824 static struct file_lock
*what_owner_is_waiting_for(struct file_lock
*block_fl
)
826 struct file_lock
*fl
;
828 hash_for_each_possible(blocked_hash
, fl
, fl_link
, posix_owner_key(block_fl
)) {
829 if (posix_same_owner(fl
, block_fl
))
835 /* Must be called with the blocked_lock_lock held! */
836 static int posix_locks_deadlock(struct file_lock
*caller_fl
,
837 struct file_lock
*block_fl
)
842 * This deadlock detector can't reasonably detect deadlocks with
843 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
845 if (IS_OFDLCK(caller_fl
))
848 while ((block_fl
= what_owner_is_waiting_for(block_fl
))) {
849 if (i
++ > MAX_DEADLK_ITERATIONS
)
851 if (posix_same_owner(caller_fl
, block_fl
))
857 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
858 * after any leases, but before any posix locks.
860 * Note that if called with an FL_EXISTS argument, the caller may determine
861 * whether or not a lock was successfully freed by testing the return
864 static int flock_lock_file(struct file
*filp
, struct file_lock
*request
)
866 struct file_lock
*new_fl
= NULL
;
867 struct file_lock
*fl
;
868 struct file_lock_context
*ctx
;
869 struct inode
*inode
= file_inode(filp
);
874 ctx
= locks_get_lock_context(inode
);
878 if (!(request
->fl_flags
& FL_ACCESS
) && (request
->fl_type
!= F_UNLCK
)) {
879 new_fl
= locks_alloc_lock();
884 spin_lock(&ctx
->flc_lock
);
885 if (request
->fl_flags
& FL_ACCESS
)
888 list_for_each_entry(fl
, &ctx
->flc_flock
, fl_list
) {
889 if (filp
!= fl
->fl_file
)
891 if (request
->fl_type
== fl
->fl_type
)
894 locks_delete_lock_ctx(fl
, &dispose
);
898 if (request
->fl_type
== F_UNLCK
) {
899 if ((request
->fl_flags
& FL_EXISTS
) && !found
)
905 list_for_each_entry(fl
, &ctx
->flc_flock
, fl_list
) {
906 if (!flock_locks_conflict(request
, fl
))
909 if (!(request
->fl_flags
& FL_SLEEP
))
911 error
= FILE_LOCK_DEFERRED
;
912 locks_insert_block(fl
, request
);
915 if (request
->fl_flags
& FL_ACCESS
)
917 locks_copy_lock(new_fl
, request
);
918 locks_insert_lock_ctx(new_fl
, &ctx
->flc_flock
);
923 spin_unlock(&ctx
->flc_lock
);
925 locks_free_lock(new_fl
);
926 locks_dispose_list(&dispose
);
930 static int __posix_lock_file(struct inode
*inode
, struct file_lock
*request
, struct file_lock
*conflock
)
932 struct file_lock
*fl
, *tmp
;
933 struct file_lock
*new_fl
= NULL
;
934 struct file_lock
*new_fl2
= NULL
;
935 struct file_lock
*left
= NULL
;
936 struct file_lock
*right
= NULL
;
937 struct file_lock_context
*ctx
;
942 ctx
= locks_get_lock_context(inode
);
947 * We may need two file_lock structures for this operation,
948 * so we get them in advance to avoid races.
950 * In some cases we can be sure, that no new locks will be needed
952 if (!(request
->fl_flags
& FL_ACCESS
) &&
953 (request
->fl_type
!= F_UNLCK
||
954 request
->fl_start
!= 0 || request
->fl_end
!= OFFSET_MAX
)) {
955 new_fl
= locks_alloc_lock();
956 new_fl2
= locks_alloc_lock();
959 spin_lock(&ctx
->flc_lock
);
961 * New lock request. Walk all POSIX locks and look for conflicts. If
962 * there are any, either return error or put the request on the
963 * blocker's list of waiters and the global blocked_hash.
965 if (request
->fl_type
!= F_UNLCK
) {
966 list_for_each_entry(fl
, &ctx
->flc_posix
, fl_list
) {
969 if (!posix_locks_conflict(request
, fl
))
972 locks_copy_conflock(conflock
, fl
);
974 if (!(request
->fl_flags
& FL_SLEEP
))
977 * Deadlock detection and insertion into the blocked
978 * locks list must be done while holding the same lock!
981 spin_lock(&blocked_lock_lock
);
982 if (likely(!posix_locks_deadlock(request
, fl
))) {
983 error
= FILE_LOCK_DEFERRED
;
984 __locks_insert_block(fl
, request
);
986 spin_unlock(&blocked_lock_lock
);
991 /* If we're just looking for a conflict, we're done. */
993 if (request
->fl_flags
& FL_ACCESS
)
996 /* Find the first old lock with the same owner as the new lock */
997 list_for_each_entry(fl
, &ctx
->flc_posix
, fl_list
) {
998 if (posix_same_owner(request
, fl
))
1002 /* Process locks with this owner. */
1003 list_for_each_entry_safe_from(fl
, tmp
, &ctx
->flc_posix
, fl_list
) {
1004 if (!posix_same_owner(request
, fl
))
1007 /* Detect adjacent or overlapping regions (if same lock type) */
1008 if (request
->fl_type
== fl
->fl_type
) {
1009 /* In all comparisons of start vs end, use
1010 * "start - 1" rather than "end + 1". If end
1011 * is OFFSET_MAX, end + 1 will become negative.
1013 if (fl
->fl_end
< request
->fl_start
- 1)
1015 /* If the next lock in the list has entirely bigger
1016 * addresses than the new one, insert the lock here.
1018 if (fl
->fl_start
- 1 > request
->fl_end
)
1021 /* If we come here, the new and old lock are of the
1022 * same type and adjacent or overlapping. Make one
1023 * lock yielding from the lower start address of both
1024 * locks to the higher end address.
1026 if (fl
->fl_start
> request
->fl_start
)
1027 fl
->fl_start
= request
->fl_start
;
1029 request
->fl_start
= fl
->fl_start
;
1030 if (fl
->fl_end
< request
->fl_end
)
1031 fl
->fl_end
= request
->fl_end
;
1033 request
->fl_end
= fl
->fl_end
;
1035 locks_delete_lock_ctx(fl
, &dispose
);
1041 /* Processing for different lock types is a bit
1044 if (fl
->fl_end
< request
->fl_start
)
1046 if (fl
->fl_start
> request
->fl_end
)
1048 if (request
->fl_type
== F_UNLCK
)
1050 if (fl
->fl_start
< request
->fl_start
)
1052 /* If the next lock in the list has a higher end
1053 * address than the new one, insert the new one here.
1055 if (fl
->fl_end
> request
->fl_end
) {
1059 if (fl
->fl_start
>= request
->fl_start
) {
1060 /* The new lock completely replaces an old
1061 * one (This may happen several times).
1064 locks_delete_lock_ctx(fl
, &dispose
);
1068 * Replace the old lock with new_fl, and
1069 * remove the old one. It's safe to do the
1070 * insert here since we know that we won't be
1071 * using new_fl later, and that the lock is
1072 * just replacing an existing lock.
1077 locks_copy_lock(new_fl
, request
);
1080 locks_insert_lock_ctx(request
, &fl
->fl_list
);
1081 locks_delete_lock_ctx(fl
, &dispose
);
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_ctx(new_fl
, &fl
->fl_list
);
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_ctx(left
, &fl
->fl_list
);
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(&ctx
->flc_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
)
1201 struct inode
*inode
= file_inode(file
);
1202 struct file_lock_context
*ctx
;
1203 struct file_lock
*fl
;
1205 ctx
= inode
->i_flctx
;
1206 if (!ctx
|| list_empty_careful(&ctx
->flc_posix
))
1210 * Search the lock list for this inode for any POSIX locks.
1212 spin_lock(&ctx
->flc_lock
);
1214 list_for_each_entry(fl
, &ctx
->flc_posix
, fl_list
) {
1215 if (fl
->fl_owner
!= current
->files
&&
1216 fl
->fl_owner
!= file
) {
1221 spin_unlock(&ctx
->flc_lock
);
1226 * locks_mandatory_area - Check for a conflicting lock
1227 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1229 * @inode: the file to check
1230 * @filp: how the file was opened (if it was)
1231 * @offset: start of area to check
1232 * @count: length of area to check
1234 * Searches the inode's list of locks to find any POSIX locks which conflict.
1235 * This function is called from rw_verify_area() and
1236 * locks_verify_truncate().
1238 int locks_mandatory_area(int read_write
, struct inode
*inode
,
1239 struct file
*filp
, loff_t offset
,
1242 struct file_lock fl
;
1246 locks_init_lock(&fl
);
1247 fl
.fl_pid
= current
->tgid
;
1249 fl
.fl_flags
= FL_POSIX
| FL_ACCESS
;
1250 if (filp
&& !(filp
->f_flags
& O_NONBLOCK
))
1252 fl
.fl_type
= (read_write
== FLOCK_VERIFY_WRITE
) ? F_WRLCK
: F_RDLCK
;
1253 fl
.fl_start
= offset
;
1254 fl
.fl_end
= offset
+ count
- 1;
1259 fl
.fl_flags
&= ~FL_SLEEP
;
1260 error
= __posix_lock_file(inode
, &fl
, NULL
);
1266 fl
.fl_flags
|= FL_SLEEP
;
1267 fl
.fl_owner
= current
->files
;
1268 error
= __posix_lock_file(inode
, &fl
, NULL
);
1269 if (error
!= FILE_LOCK_DEFERRED
)
1271 error
= wait_event_interruptible(fl
.fl_wait
, !fl
.fl_next
);
1274 * If we've been sleeping someone might have
1275 * changed the permissions behind our back.
1277 if (__mandatory_lock(inode
))
1281 locks_delete_block(&fl
);
1288 EXPORT_SYMBOL(locks_mandatory_area
);
1290 static void lease_clear_pending(struct file_lock
*fl
, int arg
)
1294 fl
->fl_flags
&= ~FL_UNLOCK_PENDING
;
1297 fl
->fl_flags
&= ~FL_DOWNGRADE_PENDING
;
1301 /* We already had a lease on this file; just change its type */
1302 int lease_modify(struct file_lock
*fl
, int arg
, struct list_head
*dispose
)
1304 int error
= assign_type(fl
, arg
);
1308 lease_clear_pending(fl
, arg
);
1309 locks_wake_up_blocks(fl
);
1310 if (arg
== F_UNLCK
) {
1311 struct file
*filp
= fl
->fl_file
;
1314 filp
->f_owner
.signum
= 0;
1315 fasync_helper(0, fl
->fl_file
, 0, &fl
->fl_fasync
);
1316 if (fl
->fl_fasync
!= NULL
) {
1317 printk(KERN_ERR
"locks_delete_lock: fasync == %p\n", fl
->fl_fasync
);
1318 fl
->fl_fasync
= NULL
;
1320 locks_delete_lock_ctx(fl
, dispose
);
1324 EXPORT_SYMBOL(lease_modify
);
1326 static bool past_time(unsigned long then
)
1329 /* 0 is a special value meaning "this never expires": */
1331 return time_after(jiffies
, then
);
1334 static void time_out_leases(struct inode
*inode
, struct list_head
*dispose
)
1336 struct file_lock_context
*ctx
= inode
->i_flctx
;
1337 struct file_lock
*fl
, *tmp
;
1339 lockdep_assert_held(&ctx
->flc_lock
);
1341 list_for_each_entry_safe(fl
, tmp
, &ctx
->flc_lease
, fl_list
) {
1342 trace_time_out_leases(inode
, fl
);
1343 if (past_time(fl
->fl_downgrade_time
))
1344 lease_modify(fl
, F_RDLCK
, dispose
);
1345 if (past_time(fl
->fl_break_time
))
1346 lease_modify(fl
, F_UNLCK
, dispose
);
1350 static bool leases_conflict(struct file_lock
*lease
, struct file_lock
*breaker
)
1352 if ((breaker
->fl_flags
& FL_LAYOUT
) != (lease
->fl_flags
& FL_LAYOUT
))
1354 if ((breaker
->fl_flags
& FL_DELEG
) && (lease
->fl_flags
& FL_LEASE
))
1356 return locks_conflict(breaker
, lease
);
1360 any_leases_conflict(struct inode
*inode
, struct file_lock
*breaker
)
1362 struct file_lock_context
*ctx
= inode
->i_flctx
;
1363 struct file_lock
*fl
;
1365 lockdep_assert_held(&ctx
->flc_lock
);
1367 list_for_each_entry(fl
, &ctx
->flc_lease
, fl_list
) {
1368 if (leases_conflict(fl
, breaker
))
1375 * __break_lease - revoke all outstanding leases on file
1376 * @inode: the inode of the file to return
1377 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1379 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1382 * break_lease (inlined for speed) has checked there already is at least
1383 * some kind of lock (maybe a lease) on this file. Leases are broken on
1384 * a call to open() or truncate(). This function can sleep unless you
1385 * specified %O_NONBLOCK to your open().
1387 int __break_lease(struct inode
*inode
, unsigned int mode
, unsigned int type
)
1390 struct file_lock
*new_fl
;
1391 struct file_lock_context
*ctx
= inode
->i_flctx
;
1392 struct file_lock
*fl
;
1393 unsigned long break_time
;
1394 int want_write
= (mode
& O_ACCMODE
) != O_RDONLY
;
1397 new_fl
= lease_alloc(NULL
, want_write
? F_WRLCK
: F_RDLCK
);
1399 return PTR_ERR(new_fl
);
1400 new_fl
->fl_flags
= type
;
1402 /* typically we will check that ctx is non-NULL before calling */
1408 spin_lock(&ctx
->flc_lock
);
1410 time_out_leases(inode
, &dispose
);
1412 if (!any_leases_conflict(inode
, new_fl
))
1416 if (lease_break_time
> 0) {
1417 break_time
= jiffies
+ lease_break_time
* HZ
;
1418 if (break_time
== 0)
1419 break_time
++; /* so that 0 means no break time */
1422 list_for_each_entry(fl
, &ctx
->flc_lease
, fl_list
) {
1423 if (!leases_conflict(fl
, new_fl
))
1426 if (fl
->fl_flags
& FL_UNLOCK_PENDING
)
1428 fl
->fl_flags
|= FL_UNLOCK_PENDING
;
1429 fl
->fl_break_time
= break_time
;
1431 if (lease_breaking(fl
))
1433 fl
->fl_flags
|= FL_DOWNGRADE_PENDING
;
1434 fl
->fl_downgrade_time
= break_time
;
1436 if (fl
->fl_lmops
->lm_break(fl
))
1437 locks_delete_lock_ctx(fl
, &dispose
);
1440 if (list_empty(&ctx
->flc_lease
))
1443 if (mode
& O_NONBLOCK
) {
1444 trace_break_lease_noblock(inode
, new_fl
);
1445 error
= -EWOULDBLOCK
;
1450 fl
= list_first_entry(&ctx
->flc_lease
, struct file_lock
, fl_list
);
1451 break_time
= fl
->fl_break_time
;
1452 if (break_time
!= 0)
1453 break_time
-= jiffies
;
1454 if (break_time
== 0)
1456 locks_insert_block(fl
, new_fl
);
1457 trace_break_lease_block(inode
, new_fl
);
1458 spin_unlock(&ctx
->flc_lock
);
1459 locks_dispose_list(&dispose
);
1460 error
= wait_event_interruptible_timeout(new_fl
->fl_wait
,
1461 !new_fl
->fl_next
, break_time
);
1462 spin_lock(&ctx
->flc_lock
);
1463 trace_break_lease_unblock(inode
, new_fl
);
1464 locks_delete_block(new_fl
);
1467 * Wait for the next conflicting lease that has not been
1471 time_out_leases(inode
, &dispose
);
1472 if (any_leases_conflict(inode
, new_fl
))
1477 spin_unlock(&ctx
->flc_lock
);
1478 locks_dispose_list(&dispose
);
1479 locks_free_lock(new_fl
);
1483 EXPORT_SYMBOL(__break_lease
);
1486 * lease_get_mtime - get the last modified time of an inode
1488 * @time: pointer to a timespec which will contain the last modified time
1490 * This is to force NFS clients to flush their caches for files with
1491 * exclusive leases. The justification is that if someone has an
1492 * exclusive lease, then they could be modifying it.
1494 void lease_get_mtime(struct inode
*inode
, struct timespec
*time
)
1496 bool has_lease
= false;
1497 struct file_lock_context
*ctx
= inode
->i_flctx
;
1498 struct file_lock
*fl
;
1500 if (ctx
&& !list_empty_careful(&ctx
->flc_lease
)) {
1501 spin_lock(&ctx
->flc_lock
);
1502 if (!list_empty(&ctx
->flc_lease
)) {
1503 fl
= list_first_entry(&ctx
->flc_lease
,
1504 struct file_lock
, fl_list
);
1505 if (fl
->fl_type
== F_WRLCK
)
1508 spin_unlock(&ctx
->flc_lock
);
1512 *time
= current_fs_time(inode
->i_sb
);
1514 *time
= inode
->i_mtime
;
1517 EXPORT_SYMBOL(lease_get_mtime
);
1520 * fcntl_getlease - Enquire what lease is currently active
1523 * The value returned by this function will be one of
1524 * (if no lease break is pending):
1526 * %F_RDLCK to indicate a shared lease is held.
1528 * %F_WRLCK to indicate an exclusive lease is held.
1530 * %F_UNLCK to indicate no lease is held.
1532 * (if a lease break is pending):
1534 * %F_RDLCK to indicate an exclusive lease needs to be
1535 * changed to a shared lease (or removed).
1537 * %F_UNLCK to indicate the lease needs to be removed.
1539 * XXX: sfr & willy disagree over whether F_INPROGRESS
1540 * should be returned to userspace.
1542 int fcntl_getlease(struct file
*filp
)
1544 struct file_lock
*fl
;
1545 struct inode
*inode
= file_inode(filp
);
1546 struct file_lock_context
*ctx
= inode
->i_flctx
;
1550 if (ctx
&& !list_empty_careful(&ctx
->flc_lease
)) {
1551 spin_lock(&ctx
->flc_lock
);
1552 time_out_leases(file_inode(filp
), &dispose
);
1553 list_for_each_entry(fl
, &ctx
->flc_lease
, fl_list
) {
1554 if (fl
->fl_file
!= filp
)
1556 type
= target_leasetype(fl
);
1559 spin_unlock(&ctx
->flc_lock
);
1560 locks_dispose_list(&dispose
);
1566 * check_conflicting_open - see if the given dentry points to a file that has
1567 * an existing open that would conflict with the
1569 * @dentry: dentry to check
1570 * @arg: type of lease that we're trying to acquire
1572 * Check to see if there's an existing open fd on this file that would
1573 * conflict with the lease we're trying to set.
1576 check_conflicting_open(const struct dentry
*dentry
, const long arg
, int flags
)
1579 struct inode
*inode
= dentry
->d_inode
;
1581 if (flags
& FL_LAYOUT
)
1584 if ((arg
== F_RDLCK
) && (atomic_read(&inode
->i_writecount
) > 0))
1587 if ((arg
== F_WRLCK
) && ((d_count(dentry
) > 1) ||
1588 (atomic_read(&inode
->i_count
) > 1)))
1595 generic_add_lease(struct file
*filp
, long arg
, struct file_lock
**flp
, void **priv
)
1597 struct file_lock
*fl
, *my_fl
= NULL
, *lease
;
1598 struct dentry
*dentry
= filp
->f_path
.dentry
;
1599 struct inode
*inode
= dentry
->d_inode
;
1600 struct file_lock_context
*ctx
;
1601 bool is_deleg
= (*flp
)->fl_flags
& FL_DELEG
;
1606 trace_generic_add_lease(inode
, lease
);
1608 ctx
= locks_get_lock_context(inode
);
1613 * In the delegation case we need mutual exclusion with
1614 * a number of operations that take the i_mutex. We trylock
1615 * because delegations are an optional optimization, and if
1616 * there's some chance of a conflict--we'd rather not
1617 * bother, maybe that's a sign this just isn't a good file to
1618 * hand out a delegation on.
1620 if (is_deleg
&& !mutex_trylock(&inode
->i_mutex
))
1623 if (is_deleg
&& arg
== F_WRLCK
) {
1624 /* Write delegations are not currently supported: */
1625 mutex_unlock(&inode
->i_mutex
);
1630 spin_lock(&ctx
->flc_lock
);
1631 time_out_leases(inode
, &dispose
);
1632 error
= check_conflicting_open(dentry
, arg
, lease
->fl_flags
);
1637 * At this point, we know that if there is an exclusive
1638 * lease on this file, then we hold it on this filp
1639 * (otherwise our open of this file would have blocked).
1640 * And if we are trying to acquire an exclusive lease,
1641 * then the file is not open by anyone (including us)
1642 * except for this filp.
1645 list_for_each_entry(fl
, &ctx
->flc_lease
, fl_list
) {
1646 if (fl
->fl_file
== filp
&&
1647 fl
->fl_owner
== lease
->fl_owner
) {
1653 * No exclusive leases if someone else has a lease on
1659 * Modifying our existing lease is OK, but no getting a
1660 * new lease if someone else is opening for write:
1662 if (fl
->fl_flags
& FL_UNLOCK_PENDING
)
1666 if (my_fl
!= NULL
) {
1667 error
= lease
->fl_lmops
->lm_change(my_fl
, arg
, &dispose
);
1677 locks_insert_lock_ctx(lease
, &ctx
->flc_lease
);
1679 * The check in break_lease() is lockless. It's possible for another
1680 * open to race in after we did the earlier check for a conflicting
1681 * open but before the lease was inserted. Check again for a
1682 * conflicting open and cancel the lease if there is one.
1684 * We also add a barrier here to ensure that the insertion of the lock
1685 * precedes these checks.
1688 error
= check_conflicting_open(dentry
, arg
, lease
->fl_flags
);
1690 locks_unlink_lock_ctx(lease
);
1695 if (lease
->fl_lmops
->lm_setup
)
1696 lease
->fl_lmops
->lm_setup(lease
, priv
);
1698 spin_unlock(&ctx
->flc_lock
);
1699 locks_dispose_list(&dispose
);
1701 mutex_unlock(&inode
->i_mutex
);
1702 if (!error
&& !my_fl
)
1707 static int generic_delete_lease(struct file
*filp
, void *owner
)
1709 int error
= -EAGAIN
;
1710 struct file_lock
*fl
, *victim
= NULL
;
1711 struct dentry
*dentry
= filp
->f_path
.dentry
;
1712 struct inode
*inode
= dentry
->d_inode
;
1713 struct file_lock_context
*ctx
= inode
->i_flctx
;
1717 trace_generic_delete_lease(inode
, NULL
);
1721 spin_lock(&ctx
->flc_lock
);
1722 list_for_each_entry(fl
, &ctx
->flc_lease
, fl_list
) {
1723 if (fl
->fl_file
== filp
&&
1724 fl
->fl_owner
== owner
) {
1729 trace_generic_delete_lease(inode
, fl
);
1731 error
= fl
->fl_lmops
->lm_change(victim
, F_UNLCK
, &dispose
);
1732 spin_unlock(&ctx
->flc_lock
);
1733 locks_dispose_list(&dispose
);
1738 * generic_setlease - sets a lease on an open file
1739 * @filp: file pointer
1740 * @arg: type of lease to obtain
1741 * @flp: input - file_lock to use, output - file_lock inserted
1742 * @priv: private data for lm_setup (may be NULL if lm_setup
1743 * doesn't require it)
1745 * The (input) flp->fl_lmops->lm_break function is required
1748 int generic_setlease(struct file
*filp
, long arg
, struct file_lock
**flp
,
1751 struct dentry
*dentry
= filp
->f_path
.dentry
;
1752 struct inode
*inode
= dentry
->d_inode
;
1755 if ((!uid_eq(current_fsuid(), inode
->i_uid
)) && !capable(CAP_LEASE
))
1757 if (!S_ISREG(inode
->i_mode
))
1759 error
= security_file_lock(filp
, arg
);
1765 return generic_delete_lease(filp
, *priv
);
1768 if (!(*flp
)->fl_lmops
->lm_break
) {
1773 return generic_add_lease(filp
, arg
, flp
, priv
);
1778 EXPORT_SYMBOL(generic_setlease
);
1781 * vfs_setlease - sets a lease on an open file
1782 * @filp: file pointer
1783 * @arg: type of lease to obtain
1784 * @lease: file_lock to use when adding a lease
1785 * @priv: private info for lm_setup when adding a lease (may be
1786 * NULL if lm_setup doesn't require it)
1788 * Call this to establish a lease on the file. The "lease" argument is not
1789 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1790 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1791 * if not, this function will return -ENOLCK (and generate a scary-looking
1794 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1795 * may be NULL if the lm_setup operation doesn't require it.
1798 vfs_setlease(struct file
*filp
, long arg
, struct file_lock
**lease
, void **priv
)
1800 if (filp
->f_op
->setlease
)
1801 return filp
->f_op
->setlease(filp
, arg
, lease
, priv
);
1803 return generic_setlease(filp
, arg
, lease
, priv
);
1805 EXPORT_SYMBOL_GPL(vfs_setlease
);
1807 static int do_fcntl_add_lease(unsigned int fd
, struct file
*filp
, long arg
)
1809 struct file_lock
*fl
;
1810 struct fasync_struct
*new;
1813 fl
= lease_alloc(filp
, arg
);
1817 new = fasync_alloc();
1819 locks_free_lock(fl
);
1824 error
= vfs_setlease(filp
, arg
, &fl
, (void **)&new);
1826 locks_free_lock(fl
);
1833 * fcntl_setlease - sets a lease on an open file
1834 * @fd: open file descriptor
1835 * @filp: file pointer
1836 * @arg: type of lease to obtain
1838 * Call this fcntl to establish a lease on the file.
1839 * Note that you also need to call %F_SETSIG to
1840 * receive a signal when the lease is broken.
1842 int fcntl_setlease(unsigned int fd
, struct file
*filp
, long arg
)
1845 return vfs_setlease(filp
, F_UNLCK
, NULL
, (void **)&filp
);
1846 return do_fcntl_add_lease(fd
, filp
, arg
);
1850 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1851 * @filp: The file to apply the lock to
1852 * @fl: The lock to be applied
1854 * Add a FLOCK style lock to a file.
1856 int flock_lock_file_wait(struct file
*filp
, struct file_lock
*fl
)
1861 error
= flock_lock_file(filp
, fl
);
1862 if (error
!= FILE_LOCK_DEFERRED
)
1864 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
1868 locks_delete_block(fl
);
1874 EXPORT_SYMBOL(flock_lock_file_wait
);
1877 * sys_flock: - flock() system call.
1878 * @fd: the file descriptor to lock.
1879 * @cmd: the type of lock to apply.
1881 * Apply a %FL_FLOCK style lock to an open file descriptor.
1882 * The @cmd can be one of
1884 * %LOCK_SH -- a shared lock.
1886 * %LOCK_EX -- an exclusive lock.
1888 * %LOCK_UN -- remove an existing lock.
1890 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1892 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1893 * processes read and write access respectively.
1895 SYSCALL_DEFINE2(flock
, unsigned int, fd
, unsigned int, cmd
)
1897 struct fd f
= fdget(fd
);
1898 struct file_lock
*lock
;
1899 int can_sleep
, unlock
;
1906 can_sleep
= !(cmd
& LOCK_NB
);
1908 unlock
= (cmd
== LOCK_UN
);
1910 if (!unlock
&& !(cmd
& LOCK_MAND
) &&
1911 !(f
.file
->f_mode
& (FMODE_READ
|FMODE_WRITE
)))
1914 lock
= flock_make_lock(f
.file
, cmd
);
1916 error
= PTR_ERR(lock
);
1921 lock
->fl_flags
|= FL_SLEEP
;
1923 error
= security_file_lock(f
.file
, lock
->fl_type
);
1927 if (f
.file
->f_op
->flock
)
1928 error
= f
.file
->f_op
->flock(f
.file
,
1929 (can_sleep
) ? F_SETLKW
: F_SETLK
,
1932 error
= flock_lock_file_wait(f
.file
, lock
);
1935 locks_free_lock(lock
);
1944 * vfs_test_lock - test file byte range lock
1945 * @filp: The file to test lock for
1946 * @fl: The lock to test; also used to hold result
1948 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1949 * setting conf->fl_type to something other than F_UNLCK.
1951 int vfs_test_lock(struct file
*filp
, struct file_lock
*fl
)
1953 if (filp
->f_op
->lock
)
1954 return filp
->f_op
->lock(filp
, F_GETLK
, fl
);
1955 posix_test_lock(filp
, fl
);
1958 EXPORT_SYMBOL_GPL(vfs_test_lock
);
1960 static int posix_lock_to_flock(struct flock
*flock
, struct file_lock
*fl
)
1962 flock
->l_pid
= IS_OFDLCK(fl
) ? -1 : fl
->fl_pid
;
1963 #if BITS_PER_LONG == 32
1965 * Make sure we can represent the posix lock via
1966 * legacy 32bit flock.
1968 if (fl
->fl_start
> OFFT_OFFSET_MAX
)
1970 if (fl
->fl_end
!= OFFSET_MAX
&& fl
->fl_end
> OFFT_OFFSET_MAX
)
1973 flock
->l_start
= fl
->fl_start
;
1974 flock
->l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1975 fl
->fl_end
- fl
->fl_start
+ 1;
1976 flock
->l_whence
= 0;
1977 flock
->l_type
= fl
->fl_type
;
1981 #if BITS_PER_LONG == 32
1982 static void posix_lock_to_flock64(struct flock64
*flock
, struct file_lock
*fl
)
1984 flock
->l_pid
= IS_OFDLCK(fl
) ? -1 : fl
->fl_pid
;
1985 flock
->l_start
= fl
->fl_start
;
1986 flock
->l_len
= fl
->fl_end
== OFFSET_MAX
? 0 :
1987 fl
->fl_end
- fl
->fl_start
+ 1;
1988 flock
->l_whence
= 0;
1989 flock
->l_type
= fl
->fl_type
;
1993 /* Report the first existing lock that would conflict with l.
1994 * This implements the F_GETLK command of fcntl().
1996 int fcntl_getlk(struct file
*filp
, unsigned int cmd
, struct flock __user
*l
)
1998 struct file_lock file_lock
;
2003 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2006 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
2009 error
= flock_to_posix_lock(filp
, &file_lock
, &flock
);
2013 if (cmd
== F_OFD_GETLK
) {
2015 if (flock
.l_pid
!= 0)
2019 file_lock
.fl_flags
|= FL_OFDLCK
;
2020 file_lock
.fl_owner
= filp
;
2023 error
= vfs_test_lock(filp
, &file_lock
);
2027 flock
.l_type
= file_lock
.fl_type
;
2028 if (file_lock
.fl_type
!= F_UNLCK
) {
2029 error
= posix_lock_to_flock(&flock
, &file_lock
);
2034 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
2037 locks_release_private(&file_lock
);
2043 * vfs_lock_file - file byte range lock
2044 * @filp: The file to apply the lock to
2045 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2046 * @fl: The lock to be applied
2047 * @conf: Place to return a copy of the conflicting lock, if found.
2049 * A caller that doesn't care about the conflicting lock may pass NULL
2050 * as the final argument.
2052 * If the filesystem defines a private ->lock() method, then @conf will
2053 * be left unchanged; so a caller that cares should initialize it to
2054 * some acceptable default.
2056 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2057 * locks, the ->lock() interface may return asynchronously, before the lock has
2058 * been granted or denied by the underlying filesystem, if (and only if)
2059 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2060 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2061 * the request is for a blocking lock. When ->lock() does return asynchronously,
2062 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2063 * request completes.
2064 * If the request is for non-blocking lock the file system should return
2065 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2066 * with the result. If the request timed out the callback routine will return a
2067 * nonzero return code and the file system should release the lock. The file
2068 * system is also responsible to keep a corresponding posix lock when it
2069 * grants a lock so the VFS can find out which locks are locally held and do
2070 * the correct lock cleanup when required.
2071 * The underlying filesystem must not drop the kernel lock or call
2072 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2075 int vfs_lock_file(struct file
*filp
, unsigned int cmd
, struct file_lock
*fl
, struct file_lock
*conf
)
2077 if (filp
->f_op
->lock
)
2078 return filp
->f_op
->lock(filp
, cmd
, fl
);
2080 return posix_lock_file(filp
, fl
, conf
);
2082 EXPORT_SYMBOL_GPL(vfs_lock_file
);
2084 static int do_lock_file_wait(struct file
*filp
, unsigned int cmd
,
2085 struct file_lock
*fl
)
2089 error
= security_file_lock(filp
, fl
->fl_type
);
2094 error
= vfs_lock_file(filp
, cmd
, fl
, NULL
);
2095 if (error
!= FILE_LOCK_DEFERRED
)
2097 error
= wait_event_interruptible(fl
->fl_wait
, !fl
->fl_next
);
2101 locks_delete_block(fl
);
2108 /* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
2110 check_fmode_for_setlk(struct file_lock
*fl
)
2112 switch (fl
->fl_type
) {
2114 if (!(fl
->fl_file
->f_mode
& FMODE_READ
))
2118 if (!(fl
->fl_file
->f_mode
& FMODE_WRITE
))
2124 /* Apply the lock described by l to an open file descriptor.
2125 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2127 int fcntl_setlk(unsigned int fd
, struct file
*filp
, unsigned int cmd
,
2128 struct flock __user
*l
)
2130 struct file_lock
*file_lock
= locks_alloc_lock();
2132 struct inode
*inode
;
2136 if (file_lock
== NULL
)
2140 * This might block, so we do it before checking the inode.
2143 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2146 inode
= file_inode(filp
);
2148 /* Don't allow mandatory locks on files that may be memory mapped
2151 if (mandatory_lock(inode
) && mapping_writably_mapped(filp
->f_mapping
)) {
2157 error
= flock_to_posix_lock(filp
, file_lock
, &flock
);
2161 error
= check_fmode_for_setlk(file_lock
);
2166 * If the cmd is requesting file-private locks, then set the
2167 * FL_OFDLCK flag and override the owner.
2172 if (flock
.l_pid
!= 0)
2176 file_lock
->fl_flags
|= FL_OFDLCK
;
2177 file_lock
->fl_owner
= filp
;
2181 if (flock
.l_pid
!= 0)
2185 file_lock
->fl_flags
|= FL_OFDLCK
;
2186 file_lock
->fl_owner
= filp
;
2189 file_lock
->fl_flags
|= FL_SLEEP
;
2192 error
= do_lock_file_wait(filp
, cmd
, file_lock
);
2195 * Attempt to detect a close/fcntl race and recover by
2196 * releasing the lock that was just acquired.
2199 * we need that spin_lock here - it prevents reordering between
2200 * update of i_flctx->flc_posix and check for it done in close().
2201 * rcu_read_lock() wouldn't do.
2203 spin_lock(¤t
->files
->file_lock
);
2205 spin_unlock(¤t
->files
->file_lock
);
2206 if (!error
&& f
!= filp
&& flock
.l_type
!= F_UNLCK
) {
2207 flock
.l_type
= F_UNLCK
;
2212 locks_free_lock(file_lock
);
2216 #if BITS_PER_LONG == 32
2217 /* Report the first existing lock that would conflict with l.
2218 * This implements the F_GETLK command of fcntl().
2220 int fcntl_getlk64(struct file
*filp
, unsigned int cmd
, struct flock64 __user
*l
)
2222 struct file_lock file_lock
;
2223 struct flock64 flock
;
2227 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2230 if ((flock
.l_type
!= F_RDLCK
) && (flock
.l_type
!= F_WRLCK
))
2233 error
= flock64_to_posix_lock(filp
, &file_lock
, &flock
);
2237 if (cmd
== F_OFD_GETLK
) {
2239 if (flock
.l_pid
!= 0)
2243 file_lock
.fl_flags
|= FL_OFDLCK
;
2244 file_lock
.fl_owner
= filp
;
2247 error
= vfs_test_lock(filp
, &file_lock
);
2251 flock
.l_type
= file_lock
.fl_type
;
2252 if (file_lock
.fl_type
!= F_UNLCK
)
2253 posix_lock_to_flock64(&flock
, &file_lock
);
2256 if (!copy_to_user(l
, &flock
, sizeof(flock
)))
2259 locks_release_private(&file_lock
);
2264 /* Apply the lock described by l to an open file descriptor.
2265 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2267 int fcntl_setlk64(unsigned int fd
, struct file
*filp
, unsigned int cmd
,
2268 struct flock64 __user
*l
)
2270 struct file_lock
*file_lock
= locks_alloc_lock();
2271 struct flock64 flock
;
2272 struct inode
*inode
;
2276 if (file_lock
== NULL
)
2280 * This might block, so we do it before checking the inode.
2283 if (copy_from_user(&flock
, l
, sizeof(flock
)))
2286 inode
= file_inode(filp
);
2288 /* Don't allow mandatory locks on files that may be memory mapped
2291 if (mandatory_lock(inode
) && mapping_writably_mapped(filp
->f_mapping
)) {
2297 error
= flock64_to_posix_lock(filp
, file_lock
, &flock
);
2301 error
= check_fmode_for_setlk(file_lock
);
2306 * If the cmd is requesting file-private locks, then set the
2307 * FL_OFDLCK flag and override the owner.
2312 if (flock
.l_pid
!= 0)
2316 file_lock
->fl_flags
|= FL_OFDLCK
;
2317 file_lock
->fl_owner
= filp
;
2321 if (flock
.l_pid
!= 0)
2325 file_lock
->fl_flags
|= FL_OFDLCK
;
2326 file_lock
->fl_owner
= filp
;
2329 file_lock
->fl_flags
|= FL_SLEEP
;
2332 error
= do_lock_file_wait(filp
, cmd
, file_lock
);
2335 * Attempt to detect a close/fcntl race and recover by
2336 * releasing the lock that was just acquired.
2338 spin_lock(¤t
->files
->file_lock
);
2340 spin_unlock(¤t
->files
->file_lock
);
2341 if (!error
&& f
!= filp
&& flock
.l_type
!= F_UNLCK
) {
2342 flock
.l_type
= F_UNLCK
;
2347 locks_free_lock(file_lock
);
2350 #endif /* BITS_PER_LONG == 32 */
2353 * This function is called when the file is being removed
2354 * from the task's fd array. POSIX locks belonging to this task
2355 * are deleted at this time.
2357 void locks_remove_posix(struct file
*filp
, fl_owner_t owner
)
2359 struct file_lock lock
;
2360 struct file_lock_context
*ctx
= file_inode(filp
)->i_flctx
;
2363 * If there are no locks held on this file, we don't need to call
2364 * posix_lock_file(). Another process could be setting a lock on this
2365 * file at the same time, but we wouldn't remove that lock anyway.
2367 if (!ctx
|| list_empty(&ctx
->flc_posix
))
2370 lock
.fl_type
= F_UNLCK
;
2371 lock
.fl_flags
= FL_POSIX
| FL_CLOSE
;
2373 lock
.fl_end
= OFFSET_MAX
;
2374 lock
.fl_owner
= owner
;
2375 lock
.fl_pid
= current
->tgid
;
2376 lock
.fl_file
= filp
;
2378 lock
.fl_lmops
= NULL
;
2380 vfs_lock_file(filp
, F_SETLK
, &lock
, NULL
);
2382 if (lock
.fl_ops
&& lock
.fl_ops
->fl_release_private
)
2383 lock
.fl_ops
->fl_release_private(&lock
);
2386 EXPORT_SYMBOL(locks_remove_posix
);
2388 /* The i_flctx must be valid when calling into here */
2390 locks_remove_flock(struct file
*filp
)
2392 struct file_lock fl
= {
2394 .fl_pid
= current
->tgid
,
2396 .fl_flags
= FL_FLOCK
,
2398 .fl_end
= OFFSET_MAX
,
2400 struct file_lock_context
*flctx
= file_inode(filp
)->i_flctx
;
2402 if (list_empty(&flctx
->flc_flock
))
2405 if (filp
->f_op
->flock
)
2406 filp
->f_op
->flock(filp
, F_SETLKW
, &fl
);
2408 flock_lock_file(filp
, &fl
);
2410 if (fl
.fl_ops
&& fl
.fl_ops
->fl_release_private
)
2411 fl
.fl_ops
->fl_release_private(&fl
);
2414 /* The i_flctx must be valid when calling into here */
2416 locks_remove_lease(struct file
*filp
)
2418 struct inode
*inode
= file_inode(filp
);
2419 struct file_lock_context
*ctx
= inode
->i_flctx
;
2420 struct file_lock
*fl
, *tmp
;
2423 if (list_empty(&ctx
->flc_lease
))
2426 spin_lock(&ctx
->flc_lock
);
2427 list_for_each_entry_safe(fl
, tmp
, &ctx
->flc_lease
, fl_list
)
2428 if (filp
== fl
->fl_file
)
2429 lease_modify(fl
, F_UNLCK
, &dispose
);
2430 spin_unlock(&ctx
->flc_lock
);
2431 locks_dispose_list(&dispose
);
2435 * This function is called on the last close of an open file.
2437 void locks_remove_file(struct file
*filp
)
2439 if (!file_inode(filp
)->i_flctx
)
2442 /* remove any OFD locks */
2443 locks_remove_posix(filp
, filp
);
2445 /* remove flock locks */
2446 locks_remove_flock(filp
);
2448 /* remove any leases */
2449 locks_remove_lease(filp
);
2453 * posix_unblock_lock - stop waiting for a file lock
2454 * @waiter: the lock which was waiting
2456 * lockd needs to block waiting for locks.
2459 posix_unblock_lock(struct file_lock
*waiter
)
2463 spin_lock(&blocked_lock_lock
);
2464 if (waiter
->fl_next
)
2465 __locks_delete_block(waiter
);
2468 spin_unlock(&blocked_lock_lock
);
2471 EXPORT_SYMBOL(posix_unblock_lock
);
2474 * vfs_cancel_lock - file byte range unblock lock
2475 * @filp: The file to apply the unblock to
2476 * @fl: The lock to be unblocked
2478 * Used by lock managers to cancel blocked requests
2480 int vfs_cancel_lock(struct file
*filp
, struct file_lock
*fl
)
2482 if (filp
->f_op
->lock
)
2483 return filp
->f_op
->lock(filp
, F_CANCELLK
, fl
);
2487 EXPORT_SYMBOL_GPL(vfs_cancel_lock
);
2489 #ifdef CONFIG_PROC_FS
2490 #include <linux/proc_fs.h>
2491 #include <linux/seq_file.h>
2493 struct locks_iterator
{
2498 static void lock_get_status(struct seq_file
*f
, struct file_lock
*fl
,
2499 loff_t id
, char *pfx
)
2501 struct inode
*inode
= NULL
;
2502 unsigned int fl_pid
;
2505 fl_pid
= pid_vnr(fl
->fl_nspid
);
2507 fl_pid
= fl
->fl_pid
;
2509 if (fl
->fl_file
!= NULL
)
2510 inode
= file_inode(fl
->fl_file
);
2512 seq_printf(f
, "%lld:%s ", id
, pfx
);
2514 if (fl
->fl_flags
& FL_ACCESS
)
2515 seq_puts(f
, "ACCESS");
2516 else if (IS_OFDLCK(fl
))
2517 seq_puts(f
, "OFDLCK");
2519 seq_puts(f
, "POSIX ");
2521 seq_printf(f
, " %s ",
2522 (inode
== NULL
) ? "*NOINODE*" :
2523 mandatory_lock(inode
) ? "MANDATORY" : "ADVISORY ");
2524 } else if (IS_FLOCK(fl
)) {
2525 if (fl
->fl_type
& LOCK_MAND
) {
2526 seq_puts(f
, "FLOCK MSNFS ");
2528 seq_puts(f
, "FLOCK ADVISORY ");
2530 } else if (IS_LEASE(fl
)) {
2531 if (fl
->fl_flags
& FL_DELEG
)
2532 seq_puts(f
, "DELEG ");
2534 seq_puts(f
, "LEASE ");
2536 if (lease_breaking(fl
))
2537 seq_puts(f
, "BREAKING ");
2538 else if (fl
->fl_file
)
2539 seq_puts(f
, "ACTIVE ");
2541 seq_puts(f
, "BREAKER ");
2543 seq_puts(f
, "UNKNOWN UNKNOWN ");
2545 if (fl
->fl_type
& LOCK_MAND
) {
2546 seq_printf(f
, "%s ",
2547 (fl
->fl_type
& LOCK_READ
)
2548 ? (fl
->fl_type
& LOCK_WRITE
) ? "RW " : "READ "
2549 : (fl
->fl_type
& LOCK_WRITE
) ? "WRITE" : "NONE ");
2551 seq_printf(f
, "%s ",
2552 (lease_breaking(fl
))
2553 ? (fl
->fl_type
== F_UNLCK
) ? "UNLCK" : "READ "
2554 : (fl
->fl_type
== F_WRLCK
) ? "WRITE" : "READ ");
2557 #ifdef WE_CAN_BREAK_LSLK_NOW
2558 seq_printf(f
, "%d %s:%ld ", fl_pid
,
2559 inode
->i_sb
->s_id
, inode
->i_ino
);
2561 /* userspace relies on this representation of dev_t ;-( */
2562 seq_printf(f
, "%d %02x:%02x:%ld ", fl_pid
,
2563 MAJOR(inode
->i_sb
->s_dev
),
2564 MINOR(inode
->i_sb
->s_dev
), inode
->i_ino
);
2567 seq_printf(f
, "%d <none>:0 ", fl_pid
);
2570 if (fl
->fl_end
== OFFSET_MAX
)
2571 seq_printf(f
, "%Ld EOF\n", fl
->fl_start
);
2573 seq_printf(f
, "%Ld %Ld\n", fl
->fl_start
, fl
->fl_end
);
2575 seq_puts(f
, "0 EOF\n");
2579 static int locks_show(struct seq_file
*f
, void *v
)
2581 struct locks_iterator
*iter
= f
->private;
2582 struct file_lock
*fl
, *bfl
;
2584 fl
= hlist_entry(v
, struct file_lock
, fl_link
);
2586 lock_get_status(f
, fl
, iter
->li_pos
, "");
2588 list_for_each_entry(bfl
, &fl
->fl_block
, fl_block
)
2589 lock_get_status(f
, bfl
, iter
->li_pos
, " ->");
2594 static void *locks_start(struct seq_file
*f
, loff_t
*pos
)
2595 __acquires(&blocked_lock_lock
)
2597 struct locks_iterator
*iter
= f
->private;
2599 iter
->li_pos
= *pos
+ 1;
2600 lg_global_lock(&file_lock_lglock
);
2601 spin_lock(&blocked_lock_lock
);
2602 return seq_hlist_start_percpu(&file_lock_list
, &iter
->li_cpu
, *pos
);
2605 static void *locks_next(struct seq_file
*f
, void *v
, loff_t
*pos
)
2607 struct locks_iterator
*iter
= f
->private;
2610 return seq_hlist_next_percpu(v
, &file_lock_list
, &iter
->li_cpu
, pos
);
2613 static void locks_stop(struct seq_file
*f
, void *v
)
2614 __releases(&blocked_lock_lock
)
2616 spin_unlock(&blocked_lock_lock
);
2617 lg_global_unlock(&file_lock_lglock
);
2620 static const struct seq_operations locks_seq_operations
= {
2621 .start
= locks_start
,
2627 static int locks_open(struct inode
*inode
, struct file
*filp
)
2629 return seq_open_private(filp
, &locks_seq_operations
,
2630 sizeof(struct locks_iterator
));
2633 static const struct file_operations proc_locks_operations
= {
2636 .llseek
= seq_lseek
,
2637 .release
= seq_release_private
,
2640 static int __init
proc_locks_init(void)
2642 proc_create("locks", 0, NULL
, &proc_locks_operations
);
2645 module_init(proc_locks_init
);
2648 static int __init
filelock_init(void)
2652 flctx_cache
= kmem_cache_create("file_lock_ctx",
2653 sizeof(struct file_lock_context
), 0, SLAB_PANIC
, NULL
);
2655 filelock_cache
= kmem_cache_create("file_lock_cache",
2656 sizeof(struct file_lock
), 0, SLAB_PANIC
, NULL
);
2658 lg_lock_init(&file_lock_lglock
, "file_lock_lglock");
2660 for_each_possible_cpu(i
)
2661 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list
, i
));
2666 core_initcall(filelock_init
);