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/security.h>
123 #include <linux/slab.h>
124 #include <linux/syscalls.h>
125 #include <linux/time.h>
126 #include <linux/rcupdate.h>
127 #include <linux/pid_namespace.h>
128 #include <linux/hashtable.h>
129 #include <linux/percpu.h>
131 #define CREATE_TRACE_POINTS
132 #include <trace/events/filelock.h>
134 #include <asm/uaccess.h>
136 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
137 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
138 #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
139 #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
141 static bool lease_breaking(struct file_lock *fl)
143 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
146 static int target_leasetype(struct file_lock *fl)
148 if (fl->fl_flags & FL_UNLOCK_PENDING)
150 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
155 int leases_enable = 1;
156 int lease_break_time = 45;
159 * The global file_lock_list is only used for displaying /proc/locks, so we
160 * keep a list on each CPU, with each list protected by its own spinlock.
161 * Global serialization is done using file_rwsem.
163 * Note that alterations to the list also require that the relevant flc_lock is
166 struct file_lock_list_struct {
168 struct hlist_head hlist;
170 static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
171 DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
174 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
175 * It is protected by blocked_lock_lock.
177 * We hash locks by lockowner in order to optimize searching for the lock a
178 * particular lockowner is waiting on.
180 * FIXME: make this value scale via some heuristic? We generally will want more
181 * buckets when we have more lockowners holding locks, but that's a little
182 * difficult to determine without knowing what the workload will look like.
184 #define BLOCKED_HASH_BITS 7
185 static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
188 * This lock protects the blocked_hash. Generally, if you're accessing it, you
189 * want to be holding this lock.
191 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
192 * pointer for file_lock structures that are acting as lock requests (in
193 * contrast to those that are acting as records of acquired locks).
195 * Note that when we acquire this lock in order to change the above fields,
196 * we often hold the flc_lock as well. In certain cases, when reading the fields
197 * protected by this lock, we can skip acquiring it iff we already hold the
200 * In particular, adding an entry to the fl_block list requires that you hold
201 * both the flc_lock and the blocked_lock_lock (acquired in that order).
202 * Deleting an entry from the list however only requires the file_lock_lock.
204 static DEFINE_SPINLOCK(blocked_lock_lock);
206 static struct kmem_cache *flctx_cache __read_mostly;
207 static struct kmem_cache *filelock_cache __read_mostly;
209 static struct file_lock_context *
210 locks_get_lock_context(struct inode *inode, int type)
212 struct file_lock_context *ctx;
214 /* paired with cmpxchg() below */
215 ctx = smp_load_acquire(&inode->i_flctx);
216 if (likely(ctx) || type == F_UNLCK)
219 ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
223 spin_lock_init(&ctx->flc_lock);
224 INIT_LIST_HEAD(&ctx->flc_flock);
225 INIT_LIST_HEAD(&ctx->flc_posix);
226 INIT_LIST_HEAD(&ctx->flc_lease);
229 * Assign the pointer if it's not already assigned. If it is, then
230 * free the context we just allocated.
232 if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
233 kmem_cache_free(flctx_cache, ctx);
234 ctx = smp_load_acquire(&inode->i_flctx);
237 trace_locks_get_lock_context(inode, type, ctx);
242 locks_dump_ctx_list(struct list_head *list, char *list_type)
244 struct file_lock *fl;
246 list_for_each_entry(fl, list, fl_list) {
247 pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
252 locks_check_ctx_lists(struct inode *inode)
254 struct file_lock_context *ctx = inode->i_flctx;
256 if (unlikely(!list_empty(&ctx->flc_flock) ||
257 !list_empty(&ctx->flc_posix) ||
258 !list_empty(&ctx->flc_lease))) {
259 pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
260 MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
262 locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
263 locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
264 locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
269 locks_free_lock_context(struct inode *inode)
271 struct file_lock_context *ctx = inode->i_flctx;
274 locks_check_ctx_lists(inode);
275 kmem_cache_free(flctx_cache, ctx);
279 static void locks_init_lock_heads(struct file_lock *fl)
281 INIT_HLIST_NODE(&fl->fl_link);
282 INIT_LIST_HEAD(&fl->fl_list);
283 INIT_LIST_HEAD(&fl->fl_block);
284 init_waitqueue_head(&fl->fl_wait);
287 /* Allocate an empty lock structure. */
288 struct file_lock *locks_alloc_lock(void)
290 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
293 locks_init_lock_heads(fl);
297 EXPORT_SYMBOL_GPL(locks_alloc_lock);
299 void locks_release_private(struct file_lock *fl)
302 if (fl->fl_ops->fl_release_private)
303 fl->fl_ops->fl_release_private(fl);
308 if (fl->fl_lmops->lm_put_owner) {
309 fl->fl_lmops->lm_put_owner(fl->fl_owner);
315 EXPORT_SYMBOL_GPL(locks_release_private);
317 /* Free a lock which is not in use. */
318 void locks_free_lock(struct file_lock *fl)
320 BUG_ON(waitqueue_active(&fl->fl_wait));
321 BUG_ON(!list_empty(&fl->fl_list));
322 BUG_ON(!list_empty(&fl->fl_block));
323 BUG_ON(!hlist_unhashed(&fl->fl_link));
325 locks_release_private(fl);
326 kmem_cache_free(filelock_cache, fl);
328 EXPORT_SYMBOL(locks_free_lock);
331 locks_dispose_list(struct list_head *dispose)
333 struct file_lock *fl;
335 while (!list_empty(dispose)) {
336 fl = list_first_entry(dispose, struct file_lock, fl_list);
337 list_del_init(&fl->fl_list);
342 void locks_init_lock(struct file_lock *fl)
344 memset(fl, 0, sizeof(struct file_lock));
345 locks_init_lock_heads(fl);
348 EXPORT_SYMBOL(locks_init_lock);
351 * Initialize a new lock from an existing file_lock structure.
353 void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
355 new->fl_owner = fl->fl_owner;
356 new->fl_pid = fl->fl_pid;
358 new->fl_flags = fl->fl_flags;
359 new->fl_type = fl->fl_type;
360 new->fl_start = fl->fl_start;
361 new->fl_end = fl->fl_end;
362 new->fl_lmops = fl->fl_lmops;
366 if (fl->fl_lmops->lm_get_owner)
367 fl->fl_lmops->lm_get_owner(fl->fl_owner);
370 EXPORT_SYMBOL(locks_copy_conflock);
372 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
374 /* "new" must be a freshly-initialized lock */
375 WARN_ON_ONCE(new->fl_ops);
377 locks_copy_conflock(new, fl);
379 new->fl_file = fl->fl_file;
380 new->fl_ops = fl->fl_ops;
383 if (fl->fl_ops->fl_copy_lock)
384 fl->fl_ops->fl_copy_lock(new, fl);
388 EXPORT_SYMBOL(locks_copy_lock);
390 static inline int flock_translate_cmd(int cmd) {
392 return cmd & (LOCK_MAND | LOCK_RW);
404 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
405 static struct file_lock *
406 flock_make_lock(struct file *filp, unsigned int cmd)
408 struct file_lock *fl;
409 int type = flock_translate_cmd(cmd);
412 return ERR_PTR(type);
414 fl = locks_alloc_lock();
416 return ERR_PTR(-ENOMEM);
420 fl->fl_pid = current->tgid;
421 fl->fl_flags = FL_FLOCK;
423 fl->fl_end = OFFSET_MAX;
428 static int assign_type(struct file_lock *fl, long type)
442 static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
445 switch (l->l_whence) {
450 fl->fl_start = filp->f_pos;
453 fl->fl_start = i_size_read(file_inode(filp));
458 if (l->l_start > OFFSET_MAX - fl->fl_start)
460 fl->fl_start += l->l_start;
461 if (fl->fl_start < 0)
464 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
465 POSIX-2001 defines it. */
467 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
469 fl->fl_end = fl->fl_start + l->l_len - 1;
471 } else if (l->l_len < 0) {
472 if (fl->fl_start + l->l_len < 0)
474 fl->fl_end = fl->fl_start - 1;
475 fl->fl_start += l->l_len;
477 fl->fl_end = OFFSET_MAX;
479 fl->fl_owner = current->files;
480 fl->fl_pid = current->tgid;
482 fl->fl_flags = FL_POSIX;
486 return assign_type(fl, l->l_type);
489 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
492 static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
495 struct flock64 ll = {
497 .l_whence = l->l_whence,
498 .l_start = l->l_start,
502 return flock64_to_posix_lock(filp, fl, &ll);
505 /* default lease lock manager operations */
507 lease_break_callback(struct file_lock *fl)
509 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
514 lease_setup(struct file_lock *fl, void **priv)
516 struct file *filp = fl->fl_file;
517 struct fasync_struct *fa = *priv;
520 * fasync_insert_entry() returns the old entry if any. If there was no
521 * old entry, then it used "priv" and inserted it into the fasync list.
522 * Clear the pointer to indicate that it shouldn't be freed.
524 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
527 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
530 static const struct lock_manager_operations lease_manager_ops = {
531 .lm_break = lease_break_callback,
532 .lm_change = lease_modify,
533 .lm_setup = lease_setup,
537 * Initialize a lease, use the default lock manager operations
539 static int lease_init(struct file *filp, long type, struct file_lock *fl)
541 if (assign_type(fl, type) != 0)
545 fl->fl_pid = current->tgid;
548 fl->fl_flags = FL_LEASE;
550 fl->fl_end = OFFSET_MAX;
552 fl->fl_lmops = &lease_manager_ops;
556 /* Allocate a file_lock initialised to this type of lease */
557 static struct file_lock *lease_alloc(struct file *filp, long type)
559 struct file_lock *fl = locks_alloc_lock();
563 return ERR_PTR(error);
565 error = lease_init(filp, type, fl);
568 return ERR_PTR(error);
573 /* Check if two locks overlap each other.
575 static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
577 return ((fl1->fl_end >= fl2->fl_start) &&
578 (fl2->fl_end >= fl1->fl_start));
582 * Check whether two locks have the same owner.
584 static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
586 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
587 return fl2->fl_lmops == fl1->fl_lmops &&
588 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
589 return fl1->fl_owner == fl2->fl_owner;
592 /* Must be called with the flc_lock held! */
593 static void locks_insert_global_locks(struct file_lock *fl)
595 struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
597 percpu_rwsem_assert_held(&file_rwsem);
599 spin_lock(&fll->lock);
600 fl->fl_link_cpu = smp_processor_id();
601 hlist_add_head(&fl->fl_link, &fll->hlist);
602 spin_unlock(&fll->lock);
605 /* Must be called with the flc_lock held! */
606 static void locks_delete_global_locks(struct file_lock *fl)
608 struct file_lock_list_struct *fll;
610 percpu_rwsem_assert_held(&file_rwsem);
613 * Avoid taking lock if already unhashed. This is safe since this check
614 * is done while holding the flc_lock, and new insertions into the list
615 * also require that it be held.
617 if (hlist_unhashed(&fl->fl_link))
620 fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
621 spin_lock(&fll->lock);
622 hlist_del_init(&fl->fl_link);
623 spin_unlock(&fll->lock);
627 posix_owner_key(struct file_lock *fl)
629 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
630 return fl->fl_lmops->lm_owner_key(fl);
631 return (unsigned long)fl->fl_owner;
634 static void locks_insert_global_blocked(struct file_lock *waiter)
636 lockdep_assert_held(&blocked_lock_lock);
638 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
641 static void locks_delete_global_blocked(struct file_lock *waiter)
643 lockdep_assert_held(&blocked_lock_lock);
645 hash_del(&waiter->fl_link);
648 /* Remove waiter from blocker's block list.
649 * When blocker ends up pointing to itself then the list is empty.
651 * Must be called with blocked_lock_lock held.
653 static void __locks_delete_block(struct file_lock *waiter)
655 locks_delete_global_blocked(waiter);
656 list_del_init(&waiter->fl_block);
657 waiter->fl_next = NULL;
660 static void locks_delete_block(struct file_lock *waiter)
662 spin_lock(&blocked_lock_lock);
663 __locks_delete_block(waiter);
664 spin_unlock(&blocked_lock_lock);
667 /* Insert waiter into blocker's block list.
668 * We use a circular list so that processes can be easily woken up in
669 * the order they blocked. The documentation doesn't require this but
670 * it seems like the reasonable thing to do.
672 * Must be called with both the flc_lock and blocked_lock_lock held. The
673 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
674 * that the flc_lock is also held on insertions we can avoid taking the
675 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
677 static void __locks_insert_block(struct file_lock *blocker,
678 struct file_lock *waiter)
680 BUG_ON(!list_empty(&waiter->fl_block));
681 waiter->fl_next = blocker;
682 list_add_tail(&waiter->fl_block, &blocker->fl_block);
683 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
684 locks_insert_global_blocked(waiter);
687 /* Must be called with flc_lock held. */
688 static void locks_insert_block(struct file_lock *blocker,
689 struct file_lock *waiter)
691 spin_lock(&blocked_lock_lock);
692 __locks_insert_block(blocker, waiter);
693 spin_unlock(&blocked_lock_lock);
697 * Wake up processes blocked waiting for blocker.
699 * Must be called with the inode->flc_lock held!
701 static void locks_wake_up_blocks(struct file_lock *blocker)
704 * Avoid taking global lock if list is empty. This is safe since new
705 * blocked requests are only added to the list under the flc_lock, and
706 * the flc_lock is always held here. Note that removal from the fl_block
707 * list does not require the flc_lock, so we must recheck list_empty()
708 * after acquiring the blocked_lock_lock.
710 if (list_empty(&blocker->fl_block))
713 spin_lock(&blocked_lock_lock);
714 while (!list_empty(&blocker->fl_block)) {
715 struct file_lock *waiter;
717 waiter = list_first_entry(&blocker->fl_block,
718 struct file_lock, fl_block);
719 __locks_delete_block(waiter);
720 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
721 waiter->fl_lmops->lm_notify(waiter);
723 wake_up(&waiter->fl_wait);
725 spin_unlock(&blocked_lock_lock);
729 locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
731 fl->fl_nspid = get_pid(task_tgid(current));
732 list_add_tail(&fl->fl_list, before);
733 locks_insert_global_locks(fl);
737 locks_unlink_lock_ctx(struct file_lock *fl)
739 locks_delete_global_locks(fl);
740 list_del_init(&fl->fl_list);
742 put_pid(fl->fl_nspid);
745 locks_wake_up_blocks(fl);
749 locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
751 locks_unlink_lock_ctx(fl);
753 list_add(&fl->fl_list, dispose);
758 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
759 * checks for shared/exclusive status of overlapping locks.
761 static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
763 if (sys_fl->fl_type == F_WRLCK)
765 if (caller_fl->fl_type == F_WRLCK)
770 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
771 * checking before calling the locks_conflict().
773 static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
775 /* POSIX locks owned by the same process do not conflict with
778 if (posix_same_owner(caller_fl, sys_fl))
781 /* Check whether they overlap */
782 if (!locks_overlap(caller_fl, sys_fl))
785 return (locks_conflict(caller_fl, sys_fl));
788 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
789 * checking before calling the locks_conflict().
791 static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
793 /* FLOCK locks referring to the same filp do not conflict with
796 if (caller_fl->fl_file == sys_fl->fl_file)
798 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
801 return (locks_conflict(caller_fl, sys_fl));
805 posix_test_lock(struct file *filp, struct file_lock *fl)
807 struct file_lock *cfl;
808 struct file_lock_context *ctx;
809 struct inode *inode = file_inode(filp);
811 ctx = smp_load_acquire(&inode->i_flctx);
812 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
813 fl->fl_type = F_UNLCK;
817 spin_lock(&ctx->flc_lock);
818 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
819 if (posix_locks_conflict(fl, cfl)) {
820 locks_copy_conflock(fl, cfl);
822 fl->fl_pid = pid_vnr(cfl->fl_nspid);
826 fl->fl_type = F_UNLCK;
828 spin_unlock(&ctx->flc_lock);
831 EXPORT_SYMBOL(posix_test_lock);
834 * Deadlock detection:
836 * We attempt to detect deadlocks that are due purely to posix file
839 * We assume that a task can be waiting for at most one lock at a time.
840 * So for any acquired lock, the process holding that lock may be
841 * waiting on at most one other lock. That lock in turns may be held by
842 * someone waiting for at most one other lock. Given a requested lock
843 * caller_fl which is about to wait for a conflicting lock block_fl, we
844 * follow this chain of waiters to ensure we are not about to create a
847 * Since we do this before we ever put a process to sleep on a lock, we
848 * are ensured that there is never a cycle; that is what guarantees that
849 * the while() loop in posix_locks_deadlock() eventually completes.
851 * Note: the above assumption may not be true when handling lock
852 * requests from a broken NFS client. It may also fail in the presence
853 * of tasks (such as posix threads) sharing the same open file table.
854 * To handle those cases, we just bail out after a few iterations.
856 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
857 * Because the owner is not even nominally tied to a thread of
858 * execution, the deadlock detection below can't reasonably work well. Just
861 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
862 * locks that just checks for the case where two tasks are attempting to
863 * upgrade from read to write locks on the same inode.
866 #define MAX_DEADLK_ITERATIONS 10
868 /* Find a lock that the owner of the given block_fl is blocking on. */
869 static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
871 struct file_lock *fl;
873 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
874 if (posix_same_owner(fl, block_fl))
880 /* Must be called with the blocked_lock_lock held! */
881 static int posix_locks_deadlock(struct file_lock *caller_fl,
882 struct file_lock *block_fl)
886 lockdep_assert_held(&blocked_lock_lock);
889 * This deadlock detector can't reasonably detect deadlocks with
890 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
892 if (IS_OFDLCK(caller_fl))
895 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
896 if (i++ > MAX_DEADLK_ITERATIONS)
898 if (posix_same_owner(caller_fl, block_fl))
904 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
905 * after any leases, but before any posix locks.
907 * Note that if called with an FL_EXISTS argument, the caller may determine
908 * whether or not a lock was successfully freed by testing the return
911 static int flock_lock_inode(struct inode *inode, struct file_lock *request)
913 struct file_lock *new_fl = NULL;
914 struct file_lock *fl;
915 struct file_lock_context *ctx;
920 ctx = locks_get_lock_context(inode, request->fl_type);
922 if (request->fl_type != F_UNLCK)
924 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
927 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
928 new_fl = locks_alloc_lock();
933 percpu_down_read_preempt_disable(&file_rwsem);
934 spin_lock(&ctx->flc_lock);
935 if (request->fl_flags & FL_ACCESS)
938 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
939 if (request->fl_file != fl->fl_file)
941 if (request->fl_type == fl->fl_type)
944 locks_delete_lock_ctx(fl, &dispose);
948 if (request->fl_type == F_UNLCK) {
949 if ((request->fl_flags & FL_EXISTS) && !found)
955 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
956 if (!flock_locks_conflict(request, fl))
959 if (!(request->fl_flags & FL_SLEEP))
961 error = FILE_LOCK_DEFERRED;
962 locks_insert_block(fl, request);
965 if (request->fl_flags & FL_ACCESS)
967 locks_copy_lock(new_fl, request);
968 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
973 spin_unlock(&ctx->flc_lock);
974 percpu_up_read_preempt_enable(&file_rwsem);
976 locks_free_lock(new_fl);
977 locks_dispose_list(&dispose);
981 static int posix_lock_inode(struct inode *inode, struct file_lock *request,
982 struct file_lock *conflock)
984 struct file_lock *fl, *tmp;
985 struct file_lock *new_fl = NULL;
986 struct file_lock *new_fl2 = NULL;
987 struct file_lock *left = NULL;
988 struct file_lock *right = NULL;
989 struct file_lock_context *ctx;
994 ctx = locks_get_lock_context(inode, request->fl_type);
996 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
999 * We may need two file_lock structures for this operation,
1000 * so we get them in advance to avoid races.
1002 * In some cases we can be sure, that no new locks will be needed
1004 if (!(request->fl_flags & FL_ACCESS) &&
1005 (request->fl_type != F_UNLCK ||
1006 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1007 new_fl = locks_alloc_lock();
1008 new_fl2 = locks_alloc_lock();
1011 percpu_down_read_preempt_disable(&file_rwsem);
1012 spin_lock(&ctx->flc_lock);
1014 * New lock request. Walk all POSIX locks and look for conflicts. If
1015 * there are any, either return error or put the request on the
1016 * blocker's list of waiters and the global blocked_hash.
1018 if (request->fl_type != F_UNLCK) {
1019 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1020 if (!posix_locks_conflict(request, fl))
1023 locks_copy_conflock(conflock, fl);
1025 if (!(request->fl_flags & FL_SLEEP))
1028 * Deadlock detection and insertion into the blocked
1029 * locks list must be done while holding the same lock!
1032 spin_lock(&blocked_lock_lock);
1033 if (likely(!posix_locks_deadlock(request, fl))) {
1034 error = FILE_LOCK_DEFERRED;
1035 __locks_insert_block(fl, request);
1037 spin_unlock(&blocked_lock_lock);
1042 /* If we're just looking for a conflict, we're done. */
1044 if (request->fl_flags & FL_ACCESS)
1047 /* Find the first old lock with the same owner as the new lock */
1048 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1049 if (posix_same_owner(request, fl))
1053 /* Process locks with this owner. */
1054 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1055 if (!posix_same_owner(request, fl))
1058 /* Detect adjacent or overlapping regions (if same lock type) */
1059 if (request->fl_type == fl->fl_type) {
1060 /* In all comparisons of start vs end, use
1061 * "start - 1" rather than "end + 1". If end
1062 * is OFFSET_MAX, end + 1 will become negative.
1064 if (fl->fl_end < request->fl_start - 1)
1066 /* If the next lock in the list has entirely bigger
1067 * addresses than the new one, insert the lock here.
1069 if (fl->fl_start - 1 > request->fl_end)
1072 /* If we come here, the new and old lock are of the
1073 * same type and adjacent or overlapping. Make one
1074 * lock yielding from the lower start address of both
1075 * locks to the higher end address.
1077 if (fl->fl_start > request->fl_start)
1078 fl->fl_start = request->fl_start;
1080 request->fl_start = fl->fl_start;
1081 if (fl->fl_end < request->fl_end)
1082 fl->fl_end = request->fl_end;
1084 request->fl_end = fl->fl_end;
1086 locks_delete_lock_ctx(fl, &dispose);
1092 /* Processing for different lock types is a bit
1095 if (fl->fl_end < request->fl_start)
1097 if (fl->fl_start > request->fl_end)
1099 if (request->fl_type == F_UNLCK)
1101 if (fl->fl_start < request->fl_start)
1103 /* If the next lock in the list has a higher end
1104 * address than the new one, insert the new one here.
1106 if (fl->fl_end > request->fl_end) {
1110 if (fl->fl_start >= request->fl_start) {
1111 /* The new lock completely replaces an old
1112 * one (This may happen several times).
1115 locks_delete_lock_ctx(fl, &dispose);
1119 * Replace the old lock with new_fl, and
1120 * remove the old one. It's safe to do the
1121 * insert here since we know that we won't be
1122 * using new_fl later, and that the lock is
1123 * just replacing an existing lock.
1128 locks_copy_lock(new_fl, request);
1131 locks_insert_lock_ctx(request, &fl->fl_list);
1132 locks_delete_lock_ctx(fl, &dispose);
1139 * The above code only modifies existing locks in case of merging or
1140 * replacing. If new lock(s) need to be inserted all modifications are
1141 * done below this, so it's safe yet to bail out.
1143 error = -ENOLCK; /* "no luck" */
1144 if (right && left == right && !new_fl2)
1149 if (request->fl_type == F_UNLCK) {
1150 if (request->fl_flags & FL_EXISTS)
1159 locks_copy_lock(new_fl, request);
1160 locks_insert_lock_ctx(new_fl, &fl->fl_list);
1165 if (left == right) {
1166 /* The new lock breaks the old one in two pieces,
1167 * so we have to use the second new lock.
1171 locks_copy_lock(left, right);
1172 locks_insert_lock_ctx(left, &fl->fl_list);
1174 right->fl_start = request->fl_end + 1;
1175 locks_wake_up_blocks(right);
1178 left->fl_end = request->fl_start - 1;
1179 locks_wake_up_blocks(left);
1182 spin_unlock(&ctx->flc_lock);
1183 percpu_up_read_preempt_enable(&file_rwsem);
1185 * Free any unused locks.
1188 locks_free_lock(new_fl);
1190 locks_free_lock(new_fl2);
1191 locks_dispose_list(&dispose);
1192 trace_posix_lock_inode(inode, request, error);
1198 * posix_lock_file - Apply a POSIX-style lock to a file
1199 * @filp: The file to apply the lock to
1200 * @fl: The lock to be applied
1201 * @conflock: Place to return a copy of the conflicting lock, if found.
1203 * Add a POSIX style lock to a file.
1204 * We merge adjacent & overlapping locks whenever possible.
1205 * POSIX locks are sorted by owner task, then by starting address
1207 * Note that if called with an FL_EXISTS argument, the caller may determine
1208 * whether or not a lock was successfully freed by testing the return
1209 * value for -ENOENT.
1211 int posix_lock_file(struct file *filp, struct file_lock *fl,
1212 struct file_lock *conflock)
1214 return posix_lock_inode(file_inode(filp), fl, conflock);
1216 EXPORT_SYMBOL(posix_lock_file);
1219 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1220 * @inode: inode of file to which lock request should be applied
1221 * @fl: The lock to be applied
1223 * Apply a POSIX style lock request to an inode.
1225 static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1230 error = posix_lock_inode(inode, fl, NULL);
1231 if (error != FILE_LOCK_DEFERRED)
1233 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1237 locks_delete_block(fl);
1243 #ifdef CONFIG_MANDATORY_FILE_LOCKING
1245 * locks_mandatory_locked - Check for an active lock
1246 * @file: the file to check
1248 * Searches the inode's list of locks to find any POSIX locks which conflict.
1249 * This function is called from locks_verify_locked() only.
1251 int locks_mandatory_locked(struct file *file)
1254 struct inode *inode = file_inode(file);
1255 struct file_lock_context *ctx;
1256 struct file_lock *fl;
1258 ctx = smp_load_acquire(&inode->i_flctx);
1259 if (!ctx || list_empty_careful(&ctx->flc_posix))
1263 * Search the lock list for this inode for any POSIX locks.
1265 spin_lock(&ctx->flc_lock);
1267 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1268 if (fl->fl_owner != current->files &&
1269 fl->fl_owner != file) {
1274 spin_unlock(&ctx->flc_lock);
1279 * locks_mandatory_area - Check for a conflicting lock
1280 * @inode: the file to check
1281 * @filp: how the file was opened (if it was)
1282 * @start: first byte in the file to check
1283 * @end: lastbyte in the file to check
1284 * @type: %F_WRLCK for a write lock, else %F_RDLCK
1286 * Searches the inode's list of locks to find any POSIX locks which conflict.
1288 int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1289 loff_t end, unsigned char type)
1291 struct file_lock fl;
1295 locks_init_lock(&fl);
1296 fl.fl_pid = current->tgid;
1298 fl.fl_flags = FL_POSIX | FL_ACCESS;
1299 if (filp && !(filp->f_flags & O_NONBLOCK))
1302 fl.fl_start = start;
1308 fl.fl_flags &= ~FL_SLEEP;
1309 error = posix_lock_inode(inode, &fl, NULL);
1315 fl.fl_flags |= FL_SLEEP;
1316 fl.fl_owner = current->files;
1317 error = posix_lock_inode(inode, &fl, NULL);
1318 if (error != FILE_LOCK_DEFERRED)
1320 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1323 * If we've been sleeping someone might have
1324 * changed the permissions behind our back.
1326 if (__mandatory_lock(inode))
1330 locks_delete_block(&fl);
1337 EXPORT_SYMBOL(locks_mandatory_area);
1338 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
1340 static void lease_clear_pending(struct file_lock *fl, int arg)
1344 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1347 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1351 /* We already had a lease on this file; just change its type */
1352 int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
1354 int error = assign_type(fl, arg);
1358 lease_clear_pending(fl, arg);
1359 locks_wake_up_blocks(fl);
1360 if (arg == F_UNLCK) {
1361 struct file *filp = fl->fl_file;
1364 filp->f_owner.signum = 0;
1365 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1366 if (fl->fl_fasync != NULL) {
1367 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1368 fl->fl_fasync = NULL;
1370 locks_delete_lock_ctx(fl, dispose);
1374 EXPORT_SYMBOL(lease_modify);
1376 static bool past_time(unsigned long then)
1379 /* 0 is a special value meaning "this never expires": */
1381 return time_after(jiffies, then);
1384 static void time_out_leases(struct inode *inode, struct list_head *dispose)
1386 struct file_lock_context *ctx = inode->i_flctx;
1387 struct file_lock *fl, *tmp;
1389 lockdep_assert_held(&ctx->flc_lock);
1391 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1392 trace_time_out_leases(inode, fl);
1393 if (past_time(fl->fl_downgrade_time))
1394 lease_modify(fl, F_RDLCK, dispose);
1395 if (past_time(fl->fl_break_time))
1396 lease_modify(fl, F_UNLCK, dispose);
1400 static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1402 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1404 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1406 return locks_conflict(breaker, lease);
1410 any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1412 struct file_lock_context *ctx = inode->i_flctx;
1413 struct file_lock *fl;
1415 lockdep_assert_held(&ctx->flc_lock);
1417 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1418 if (leases_conflict(fl, breaker))
1425 * __break_lease - revoke all outstanding leases on file
1426 * @inode: the inode of the file to return
1427 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1429 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1432 * break_lease (inlined for speed) has checked there already is at least
1433 * some kind of lock (maybe a lease) on this file. Leases are broken on
1434 * a call to open() or truncate(). This function can sleep unless you
1435 * specified %O_NONBLOCK to your open().
1437 int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1440 struct file_lock_context *ctx;
1441 struct file_lock *new_fl, *fl, *tmp;
1442 unsigned long break_time;
1443 int want_write = (mode & O_ACCMODE) != O_RDONLY;
1446 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1448 return PTR_ERR(new_fl);
1449 new_fl->fl_flags = type;
1451 /* typically we will check that ctx is non-NULL before calling */
1452 ctx = smp_load_acquire(&inode->i_flctx);
1458 percpu_down_read_preempt_disable(&file_rwsem);
1459 spin_lock(&ctx->flc_lock);
1461 time_out_leases(inode, &dispose);
1463 if (!any_leases_conflict(inode, new_fl))
1467 if (lease_break_time > 0) {
1468 break_time = jiffies + lease_break_time * HZ;
1469 if (break_time == 0)
1470 break_time++; /* so that 0 means no break time */
1473 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1474 if (!leases_conflict(fl, new_fl))
1477 if (fl->fl_flags & FL_UNLOCK_PENDING)
1479 fl->fl_flags |= FL_UNLOCK_PENDING;
1480 fl->fl_break_time = break_time;
1482 if (lease_breaking(fl))
1484 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1485 fl->fl_downgrade_time = break_time;
1487 if (fl->fl_lmops->lm_break(fl))
1488 locks_delete_lock_ctx(fl, &dispose);
1491 if (list_empty(&ctx->flc_lease))
1494 if (mode & O_NONBLOCK) {
1495 trace_break_lease_noblock(inode, new_fl);
1496 error = -EWOULDBLOCK;
1501 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1502 break_time = fl->fl_break_time;
1503 if (break_time != 0)
1504 break_time -= jiffies;
1505 if (break_time == 0)
1507 locks_insert_block(fl, new_fl);
1508 trace_break_lease_block(inode, new_fl);
1509 spin_unlock(&ctx->flc_lock);
1510 percpu_up_read_preempt_enable(&file_rwsem);
1512 locks_dispose_list(&dispose);
1513 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1514 !new_fl->fl_next, break_time);
1516 percpu_down_read_preempt_disable(&file_rwsem);
1517 spin_lock(&ctx->flc_lock);
1518 trace_break_lease_unblock(inode, new_fl);
1519 locks_delete_block(new_fl);
1522 * Wait for the next conflicting lease that has not been
1526 time_out_leases(inode, &dispose);
1527 if (any_leases_conflict(inode, new_fl))
1532 spin_unlock(&ctx->flc_lock);
1533 percpu_up_read_preempt_enable(&file_rwsem);
1534 locks_dispose_list(&dispose);
1535 locks_free_lock(new_fl);
1539 EXPORT_SYMBOL(__break_lease);
1542 * lease_get_mtime - get the last modified time of an inode
1544 * @time: pointer to a timespec which will contain the last modified time
1546 * This is to force NFS clients to flush their caches for files with
1547 * exclusive leases. The justification is that if someone has an
1548 * exclusive lease, then they could be modifying it.
1550 void lease_get_mtime(struct inode *inode, struct timespec *time)
1552 bool has_lease = false;
1553 struct file_lock_context *ctx;
1554 struct file_lock *fl;
1556 ctx = smp_load_acquire(&inode->i_flctx);
1557 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1558 spin_lock(&ctx->flc_lock);
1559 fl = list_first_entry_or_null(&ctx->flc_lease,
1560 struct file_lock, fl_list);
1561 if (fl && (fl->fl_type == F_WRLCK))
1563 spin_unlock(&ctx->flc_lock);
1567 *time = current_fs_time(inode->i_sb);
1569 *time = inode->i_mtime;
1572 EXPORT_SYMBOL(lease_get_mtime);
1575 * fcntl_getlease - Enquire what lease is currently active
1578 * The value returned by this function will be one of
1579 * (if no lease break is pending):
1581 * %F_RDLCK to indicate a shared lease is held.
1583 * %F_WRLCK to indicate an exclusive lease is held.
1585 * %F_UNLCK to indicate no lease is held.
1587 * (if a lease break is pending):
1589 * %F_RDLCK to indicate an exclusive lease needs to be
1590 * changed to a shared lease (or removed).
1592 * %F_UNLCK to indicate the lease needs to be removed.
1594 * XXX: sfr & willy disagree over whether F_INPROGRESS
1595 * should be returned to userspace.
1597 int fcntl_getlease(struct file *filp)
1599 struct file_lock *fl;
1600 struct inode *inode = file_inode(filp);
1601 struct file_lock_context *ctx;
1605 ctx = smp_load_acquire(&inode->i_flctx);
1606 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1607 spin_lock(&ctx->flc_lock);
1608 time_out_leases(file_inode(filp), &dispose);
1609 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1610 if (fl->fl_file != filp)
1612 type = target_leasetype(fl);
1615 spin_unlock(&ctx->flc_lock);
1616 locks_dispose_list(&dispose);
1622 * check_conflicting_open - see if the given dentry points to a file that has
1623 * an existing open that would conflict with the
1625 * @dentry: dentry to check
1626 * @arg: type of lease that we're trying to acquire
1627 * @flags: current lock flags
1629 * Check to see if there's an existing open fd on this file that would
1630 * conflict with the lease we're trying to set.
1633 check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
1636 struct inode *inode = dentry->d_inode;
1638 if (flags & FL_LAYOUT)
1641 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1644 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1645 (atomic_read(&inode->i_count) > 1)))
1652 generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1654 struct file_lock *fl, *my_fl = NULL, *lease;
1655 struct dentry *dentry = filp->f_path.dentry;
1656 struct inode *inode = file_inode(filp);
1657 struct file_lock_context *ctx;
1658 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1663 trace_generic_add_lease(inode, lease);
1665 /* Note that arg is never F_UNLCK here */
1666 ctx = locks_get_lock_context(inode, arg);
1671 * In the delegation case we need mutual exclusion with
1672 * a number of operations that take the i_mutex. We trylock
1673 * because delegations are an optional optimization, and if
1674 * there's some chance of a conflict--we'd rather not
1675 * bother, maybe that's a sign this just isn't a good file to
1676 * hand out a delegation on.
1678 if (is_deleg && !inode_trylock(inode))
1681 if (is_deleg && arg == F_WRLCK) {
1682 /* Write delegations are not currently supported: */
1683 inode_unlock(inode);
1688 percpu_down_read_preempt_disable(&file_rwsem);
1689 spin_lock(&ctx->flc_lock);
1690 time_out_leases(inode, &dispose);
1691 error = check_conflicting_open(dentry, arg, lease->fl_flags);
1696 * At this point, we know that if there is an exclusive
1697 * lease on this file, then we hold it on this filp
1698 * (otherwise our open of this file would have blocked).
1699 * And if we are trying to acquire an exclusive lease,
1700 * then the file is not open by anyone (including us)
1701 * except for this filp.
1704 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1705 if (fl->fl_file == filp &&
1706 fl->fl_owner == lease->fl_owner) {
1712 * No exclusive leases if someone else has a lease on
1718 * Modifying our existing lease is OK, but no getting a
1719 * new lease if someone else is opening for write:
1721 if (fl->fl_flags & FL_UNLOCK_PENDING)
1725 if (my_fl != NULL) {
1727 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
1737 locks_insert_lock_ctx(lease, &ctx->flc_lease);
1739 * The check in break_lease() is lockless. It's possible for another
1740 * open to race in after we did the earlier check for a conflicting
1741 * open but before the lease was inserted. Check again for a
1742 * conflicting open and cancel the lease if there is one.
1744 * We also add a barrier here to ensure that the insertion of the lock
1745 * precedes these checks.
1748 error = check_conflicting_open(dentry, arg, lease->fl_flags);
1750 locks_unlink_lock_ctx(lease);
1755 if (lease->fl_lmops->lm_setup)
1756 lease->fl_lmops->lm_setup(lease, priv);
1758 spin_unlock(&ctx->flc_lock);
1759 percpu_up_read_preempt_enable(&file_rwsem);
1760 locks_dispose_list(&dispose);
1762 inode_unlock(inode);
1763 if (!error && !my_fl)
1768 static int generic_delete_lease(struct file *filp, void *owner)
1770 int error = -EAGAIN;
1771 struct file_lock *fl, *victim = NULL;
1772 struct inode *inode = file_inode(filp);
1773 struct file_lock_context *ctx;
1776 ctx = smp_load_acquire(&inode->i_flctx);
1778 trace_generic_delete_lease(inode, NULL);
1782 percpu_down_read_preempt_disable(&file_rwsem);
1783 spin_lock(&ctx->flc_lock);
1784 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1785 if (fl->fl_file == filp &&
1786 fl->fl_owner == owner) {
1791 trace_generic_delete_lease(inode, victim);
1793 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
1794 spin_unlock(&ctx->flc_lock);
1795 percpu_up_read_preempt_enable(&file_rwsem);
1796 locks_dispose_list(&dispose);
1801 * generic_setlease - sets a lease on an open file
1802 * @filp: file pointer
1803 * @arg: type of lease to obtain
1804 * @flp: input - file_lock to use, output - file_lock inserted
1805 * @priv: private data for lm_setup (may be NULL if lm_setup
1806 * doesn't require it)
1808 * The (input) flp->fl_lmops->lm_break function is required
1811 int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1814 struct inode *inode = file_inode(filp);
1817 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1819 if (!S_ISREG(inode->i_mode))
1821 error = security_file_lock(filp, arg);
1827 return generic_delete_lease(filp, *priv);
1830 if (!(*flp)->fl_lmops->lm_break) {
1835 return generic_add_lease(filp, arg, flp, priv);
1840 EXPORT_SYMBOL(generic_setlease);
1843 * vfs_setlease - sets a lease on an open file
1844 * @filp: file pointer
1845 * @arg: type of lease to obtain
1846 * @lease: file_lock to use when adding a lease
1847 * @priv: private info for lm_setup when adding a lease (may be
1848 * NULL if lm_setup doesn't require it)
1850 * Call this to establish a lease on the file. The "lease" argument is not
1851 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1852 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1853 * if not, this function will return -ENOLCK (and generate a scary-looking
1856 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1857 * may be NULL if the lm_setup operation doesn't require it.
1860 vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
1862 if (filp->f_op->setlease)
1863 return filp->f_op->setlease(filp, arg, lease, priv);
1865 return generic_setlease(filp, arg, lease, priv);
1867 EXPORT_SYMBOL_GPL(vfs_setlease);
1869 static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
1871 struct file_lock *fl;
1872 struct fasync_struct *new;
1875 fl = lease_alloc(filp, arg);
1879 new = fasync_alloc();
1881 locks_free_lock(fl);
1886 error = vfs_setlease(filp, arg, &fl, (void **)&new);
1888 locks_free_lock(fl);
1895 * fcntl_setlease - sets a lease on an open file
1896 * @fd: open file descriptor
1897 * @filp: file pointer
1898 * @arg: type of lease to obtain
1900 * Call this fcntl to establish a lease on the file.
1901 * Note that you also need to call %F_SETSIG to
1902 * receive a signal when the lease is broken.
1904 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1907 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
1908 return do_fcntl_add_lease(fd, filp, arg);
1912 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1913 * @inode: inode of the file to apply to
1914 * @fl: The lock to be applied
1916 * Apply a FLOCK style lock request to an inode.
1918 static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1923 error = flock_lock_inode(inode, fl);
1924 if (error != FILE_LOCK_DEFERRED)
1926 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1930 locks_delete_block(fl);
1937 * locks_lock_inode_wait - Apply a lock to an inode
1938 * @inode: inode of the file to apply to
1939 * @fl: The lock to be applied
1941 * Apply a POSIX or FLOCK style lock request to an inode.
1943 int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1946 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1948 res = posix_lock_inode_wait(inode, fl);
1951 res = flock_lock_inode_wait(inode, fl);
1958 EXPORT_SYMBOL(locks_lock_inode_wait);
1961 * sys_flock: - flock() system call.
1962 * @fd: the file descriptor to lock.
1963 * @cmd: the type of lock to apply.
1965 * Apply a %FL_FLOCK style lock to an open file descriptor.
1966 * The @cmd can be one of
1968 * %LOCK_SH -- a shared lock.
1970 * %LOCK_EX -- an exclusive lock.
1972 * %LOCK_UN -- remove an existing lock.
1974 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1976 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1977 * processes read and write access respectively.
1979 SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
1981 struct fd f = fdget(fd);
1982 struct file_lock *lock;
1983 int can_sleep, unlock;
1990 can_sleep = !(cmd & LOCK_NB);
1992 unlock = (cmd == LOCK_UN);
1994 if (!unlock && !(cmd & LOCK_MAND) &&
1995 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
1998 lock = flock_make_lock(f.file, cmd);
2000 error = PTR_ERR(lock);
2005 lock->fl_flags |= FL_SLEEP;
2007 error = security_file_lock(f.file, lock->fl_type);
2011 if (f.file->f_op->flock)
2012 error = f.file->f_op->flock(f.file,
2013 (can_sleep) ? F_SETLKW : F_SETLK,
2016 error = locks_lock_file_wait(f.file, lock);
2019 locks_free_lock(lock);
2028 * vfs_test_lock - test file byte range lock
2029 * @filp: The file to test lock for
2030 * @fl: The lock to test; also used to hold result
2032 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2033 * setting conf->fl_type to something other than F_UNLCK.
2035 int vfs_test_lock(struct file *filp, struct file_lock *fl)
2037 if (filp->f_op->lock)
2038 return filp->f_op->lock(filp, F_GETLK, fl);
2039 posix_test_lock(filp, fl);
2042 EXPORT_SYMBOL_GPL(vfs_test_lock);
2044 static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2046 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
2047 #if BITS_PER_LONG == 32
2049 * Make sure we can represent the posix lock via
2050 * legacy 32bit flock.
2052 if (fl->fl_start > OFFT_OFFSET_MAX)
2054 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2057 flock->l_start = fl->fl_start;
2058 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2059 fl->fl_end - fl->fl_start + 1;
2060 flock->l_whence = 0;
2061 flock->l_type = fl->fl_type;
2065 #if BITS_PER_LONG == 32
2066 static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2068 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
2069 flock->l_start = fl->fl_start;
2070 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2071 fl->fl_end - fl->fl_start + 1;
2072 flock->l_whence = 0;
2073 flock->l_type = fl->fl_type;
2077 /* Report the first existing lock that would conflict with l.
2078 * This implements the F_GETLK command of fcntl().
2080 int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
2082 struct file_lock file_lock;
2087 if (copy_from_user(&flock, l, sizeof(flock)))
2090 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2093 error = flock_to_posix_lock(filp, &file_lock, &flock);
2097 if (cmd == F_OFD_GETLK) {
2099 if (flock.l_pid != 0)
2103 file_lock.fl_flags |= FL_OFDLCK;
2104 file_lock.fl_owner = filp;
2107 error = vfs_test_lock(filp, &file_lock);
2111 flock.l_type = file_lock.fl_type;
2112 if (file_lock.fl_type != F_UNLCK) {
2113 error = posix_lock_to_flock(&flock, &file_lock);
2118 if (!copy_to_user(l, &flock, sizeof(flock)))
2121 locks_release_private(&file_lock);
2127 * vfs_lock_file - file byte range lock
2128 * @filp: The file to apply the lock to
2129 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2130 * @fl: The lock to be applied
2131 * @conf: Place to return a copy of the conflicting lock, if found.
2133 * A caller that doesn't care about the conflicting lock may pass NULL
2134 * as the final argument.
2136 * If the filesystem defines a private ->lock() method, then @conf will
2137 * be left unchanged; so a caller that cares should initialize it to
2138 * some acceptable default.
2140 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2141 * locks, the ->lock() interface may return asynchronously, before the lock has
2142 * been granted or denied by the underlying filesystem, if (and only if)
2143 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2144 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2145 * the request is for a blocking lock. When ->lock() does return asynchronously,
2146 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2147 * request completes.
2148 * If the request is for non-blocking lock the file system should return
2149 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2150 * with the result. If the request timed out the callback routine will return a
2151 * nonzero return code and the file system should release the lock. The file
2152 * system is also responsible to keep a corresponding posix lock when it
2153 * grants a lock so the VFS can find out which locks are locally held and do
2154 * the correct lock cleanup when required.
2155 * The underlying filesystem must not drop the kernel lock or call
2156 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2159 int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2161 if (filp->f_op->lock)
2162 return filp->f_op->lock(filp, cmd, fl);
2164 return posix_lock_file(filp, fl, conf);
2166 EXPORT_SYMBOL_GPL(vfs_lock_file);
2168 static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2169 struct file_lock *fl)
2173 error = security_file_lock(filp, fl->fl_type);
2178 error = vfs_lock_file(filp, cmd, fl, NULL);
2179 if (error != FILE_LOCK_DEFERRED)
2181 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2185 locks_delete_block(fl);
2192 /* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
2194 check_fmode_for_setlk(struct file_lock *fl)
2196 switch (fl->fl_type) {
2198 if (!(fl->fl_file->f_mode & FMODE_READ))
2202 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2208 /* Apply the lock described by l to an open file descriptor.
2209 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2211 int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2212 struct flock __user *l)
2214 struct file_lock *file_lock = locks_alloc_lock();
2216 struct inode *inode;
2220 if (file_lock == NULL)
2223 inode = file_inode(filp);
2226 * This might block, so we do it before checking the inode.
2229 if (copy_from_user(&flock, l, sizeof(flock)))
2232 /* Don't allow mandatory locks on files that may be memory mapped
2235 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2240 error = flock_to_posix_lock(filp, file_lock, &flock);
2244 error = check_fmode_for_setlk(file_lock);
2249 * If the cmd is requesting file-private locks, then set the
2250 * FL_OFDLCK flag and override the owner.
2255 if (flock.l_pid != 0)
2259 file_lock->fl_flags |= FL_OFDLCK;
2260 file_lock->fl_owner = filp;
2264 if (flock.l_pid != 0)
2268 file_lock->fl_flags |= FL_OFDLCK;
2269 file_lock->fl_owner = filp;
2272 file_lock->fl_flags |= FL_SLEEP;
2275 error = do_lock_file_wait(filp, cmd, file_lock);
2278 * Attempt to detect a close/fcntl race and recover by releasing the
2279 * lock that was just acquired. There is no need to do that when we're
2280 * unlocking though, or for OFD locks.
2282 if (!error && file_lock->fl_type != F_UNLCK &&
2283 !(file_lock->fl_flags & FL_OFDLCK)) {
2285 * We need that spin_lock here - it prevents reordering between
2286 * update of i_flctx->flc_posix and check for it done in
2287 * close(). rcu_read_lock() wouldn't do.
2289 spin_lock(¤t->files->file_lock);
2291 spin_unlock(¤t->files->file_lock);
2293 file_lock->fl_type = F_UNLCK;
2294 error = do_lock_file_wait(filp, cmd, file_lock);
2295 WARN_ON_ONCE(error);
2300 trace_fcntl_setlk(inode, file_lock, error);
2301 locks_free_lock(file_lock);
2305 #if BITS_PER_LONG == 32
2306 /* Report the first existing lock that would conflict with l.
2307 * This implements the F_GETLK command of fcntl().
2309 int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
2311 struct file_lock file_lock;
2312 struct flock64 flock;
2316 if (copy_from_user(&flock, l, sizeof(flock)))
2319 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2322 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2326 if (cmd == F_OFD_GETLK) {
2328 if (flock.l_pid != 0)
2332 file_lock.fl_flags |= FL_OFDLCK;
2333 file_lock.fl_owner = filp;
2336 error = vfs_test_lock(filp, &file_lock);
2340 flock.l_type = file_lock.fl_type;
2341 if (file_lock.fl_type != F_UNLCK)
2342 posix_lock_to_flock64(&flock, &file_lock);
2345 if (!copy_to_user(l, &flock, sizeof(flock)))
2348 locks_release_private(&file_lock);
2353 /* Apply the lock described by l to an open file descriptor.
2354 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2356 int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2357 struct flock64 __user *l)
2359 struct file_lock *file_lock = locks_alloc_lock();
2360 struct flock64 flock;
2361 struct inode *inode;
2365 if (file_lock == NULL)
2369 * This might block, so we do it before checking the inode.
2372 if (copy_from_user(&flock, l, sizeof(flock)))
2375 inode = file_inode(filp);
2377 /* Don't allow mandatory locks on files that may be memory mapped
2380 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2385 error = flock64_to_posix_lock(filp, file_lock, &flock);
2389 error = check_fmode_for_setlk(file_lock);
2394 * If the cmd is requesting file-private locks, then set the
2395 * FL_OFDLCK flag and override the owner.
2400 if (flock.l_pid != 0)
2404 file_lock->fl_flags |= FL_OFDLCK;
2405 file_lock->fl_owner = filp;
2409 if (flock.l_pid != 0)
2413 file_lock->fl_flags |= FL_OFDLCK;
2414 file_lock->fl_owner = filp;
2417 file_lock->fl_flags |= FL_SLEEP;
2420 error = do_lock_file_wait(filp, cmd, file_lock);
2423 * Attempt to detect a close/fcntl race and recover by releasing the
2424 * lock that was just acquired. There is no need to do that when we're
2425 * unlocking though, or for OFD locks.
2427 if (!error && file_lock->fl_type != F_UNLCK &&
2428 !(file_lock->fl_flags & FL_OFDLCK)) {
2430 * We need that spin_lock here - it prevents reordering between
2431 * update of i_flctx->flc_posix and check for it done in
2432 * close(). rcu_read_lock() wouldn't do.
2434 spin_lock(¤t->files->file_lock);
2436 spin_unlock(¤t->files->file_lock);
2438 file_lock->fl_type = F_UNLCK;
2439 error = do_lock_file_wait(filp, cmd, file_lock);
2440 WARN_ON_ONCE(error);
2445 locks_free_lock(file_lock);
2448 #endif /* BITS_PER_LONG == 32 */
2451 * This function is called when the file is being removed
2452 * from the task's fd array. POSIX locks belonging to this task
2453 * are deleted at this time.
2455 void locks_remove_posix(struct file *filp, fl_owner_t owner)
2458 struct file_lock lock;
2459 struct file_lock_context *ctx;
2462 * If there are no locks held on this file, we don't need to call
2463 * posix_lock_file(). Another process could be setting a lock on this
2464 * file at the same time, but we wouldn't remove that lock anyway.
2466 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
2467 if (!ctx || list_empty(&ctx->flc_posix))
2470 lock.fl_type = F_UNLCK;
2471 lock.fl_flags = FL_POSIX | FL_CLOSE;
2473 lock.fl_end = OFFSET_MAX;
2474 lock.fl_owner = owner;
2475 lock.fl_pid = current->tgid;
2476 lock.fl_file = filp;
2478 lock.fl_lmops = NULL;
2480 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
2482 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2483 lock.fl_ops->fl_release_private(&lock);
2484 trace_locks_remove_posix(file_inode(filp), &lock, error);
2487 EXPORT_SYMBOL(locks_remove_posix);
2489 /* The i_flctx must be valid when calling into here */
2491 locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
2493 struct file_lock fl = {
2495 .fl_pid = current->tgid,
2497 .fl_flags = FL_FLOCK,
2499 .fl_end = OFFSET_MAX,
2501 struct inode *inode = file_inode(filp);
2503 if (list_empty(&flctx->flc_flock))
2506 if (filp->f_op->flock)
2507 filp->f_op->flock(filp, F_SETLKW, &fl);
2509 flock_lock_inode(inode, &fl);
2511 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2512 fl.fl_ops->fl_release_private(&fl);
2515 /* The i_flctx must be valid when calling into here */
2517 locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
2519 struct file_lock *fl, *tmp;
2522 if (list_empty(&ctx->flc_lease))
2525 spin_lock(&ctx->flc_lock);
2526 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
2527 if (filp == fl->fl_file)
2528 lease_modify(fl, F_UNLCK, &dispose);
2529 spin_unlock(&ctx->flc_lock);
2530 locks_dispose_list(&dispose);
2534 * This function is called on the last close of an open file.
2536 void locks_remove_file(struct file *filp)
2538 struct file_lock_context *ctx;
2540 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
2544 /* remove any OFD locks */
2545 locks_remove_posix(filp, filp);
2547 /* remove flock locks */
2548 locks_remove_flock(filp, ctx);
2550 /* remove any leases */
2551 locks_remove_lease(filp, ctx);
2555 * posix_unblock_lock - stop waiting for a file lock
2556 * @waiter: the lock which was waiting
2558 * lockd needs to block waiting for locks.
2561 posix_unblock_lock(struct file_lock *waiter)
2565 spin_lock(&blocked_lock_lock);
2566 if (waiter->fl_next)
2567 __locks_delete_block(waiter);
2570 spin_unlock(&blocked_lock_lock);
2573 EXPORT_SYMBOL(posix_unblock_lock);
2576 * vfs_cancel_lock - file byte range unblock lock
2577 * @filp: The file to apply the unblock to
2578 * @fl: The lock to be unblocked
2580 * Used by lock managers to cancel blocked requests
2582 int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2584 if (filp->f_op->lock)
2585 return filp->f_op->lock(filp, F_CANCELLK, fl);
2589 EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2591 #ifdef CONFIG_PROC_FS
2592 #include <linux/proc_fs.h>
2593 #include <linux/seq_file.h>
2595 struct locks_iterator {
2600 static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2601 loff_t id, char *pfx)
2603 struct inode *inode = NULL;
2604 unsigned int fl_pid;
2607 struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
2609 /* Don't let fl_pid change based on who is reading the file */
2610 fl_pid = pid_nr_ns(fl->fl_nspid, proc_pidns);
2613 * If there isn't a fl_pid don't display who is waiting on
2614 * the lock if we are called from locks_show, or if we are
2615 * called from __show_fd_info - skip lock entirely
2620 fl_pid = fl->fl_pid;
2622 if (fl->fl_file != NULL)
2623 inode = file_inode(fl->fl_file);
2625 seq_printf(f, "%lld:%s ", id, pfx);
2627 if (fl->fl_flags & FL_ACCESS)
2628 seq_puts(f, "ACCESS");
2629 else if (IS_OFDLCK(fl))
2630 seq_puts(f, "OFDLCK");
2632 seq_puts(f, "POSIX ");
2634 seq_printf(f, " %s ",
2635 (inode == NULL) ? "*NOINODE*" :
2636 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2637 } else if (IS_FLOCK(fl)) {
2638 if (fl->fl_type & LOCK_MAND) {
2639 seq_puts(f, "FLOCK MSNFS ");
2641 seq_puts(f, "FLOCK ADVISORY ");
2643 } else if (IS_LEASE(fl)) {
2644 if (fl->fl_flags & FL_DELEG)
2645 seq_puts(f, "DELEG ");
2647 seq_puts(f, "LEASE ");
2649 if (lease_breaking(fl))
2650 seq_puts(f, "BREAKING ");
2651 else if (fl->fl_file)
2652 seq_puts(f, "ACTIVE ");
2654 seq_puts(f, "BREAKER ");
2656 seq_puts(f, "UNKNOWN UNKNOWN ");
2658 if (fl->fl_type & LOCK_MAND) {
2659 seq_printf(f, "%s ",
2660 (fl->fl_type & LOCK_READ)
2661 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2662 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2664 seq_printf(f, "%s ",
2665 (lease_breaking(fl))
2666 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2667 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
2670 /* userspace relies on this representation of dev_t */
2671 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
2672 MAJOR(inode->i_sb->s_dev),
2673 MINOR(inode->i_sb->s_dev), inode->i_ino);
2675 seq_printf(f, "%d <none>:0 ", fl_pid);
2678 if (fl->fl_end == OFFSET_MAX)
2679 seq_printf(f, "%Ld EOF\n", fl->fl_start);
2681 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2683 seq_puts(f, "0 EOF\n");
2687 static int locks_show(struct seq_file *f, void *v)
2689 struct locks_iterator *iter = f->private;
2690 struct file_lock *fl, *bfl;
2691 struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
2693 fl = hlist_entry(v, struct file_lock, fl_link);
2695 if (fl->fl_nspid && !pid_nr_ns(fl->fl_nspid, proc_pidns))
2698 lock_get_status(f, fl, iter->li_pos, "");
2700 list_for_each_entry(bfl, &fl->fl_block, fl_block)
2701 lock_get_status(f, bfl, iter->li_pos, " ->");
2706 static void __show_fd_locks(struct seq_file *f,
2707 struct list_head *head, int *id,
2708 struct file *filp, struct files_struct *files)
2710 struct file_lock *fl;
2712 list_for_each_entry(fl, head, fl_list) {
2714 if (filp != fl->fl_file)
2716 if (fl->fl_owner != files &&
2717 fl->fl_owner != filp)
2721 seq_puts(f, "lock:\t");
2722 lock_get_status(f, fl, *id, "");
2726 void show_fd_locks(struct seq_file *f,
2727 struct file *filp, struct files_struct *files)
2729 struct inode *inode = file_inode(filp);
2730 struct file_lock_context *ctx;
2733 ctx = smp_load_acquire(&inode->i_flctx);
2737 spin_lock(&ctx->flc_lock);
2738 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2739 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2740 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2741 spin_unlock(&ctx->flc_lock);
2744 static void *locks_start(struct seq_file *f, loff_t *pos)
2745 __acquires(&blocked_lock_lock)
2747 struct locks_iterator *iter = f->private;
2749 iter->li_pos = *pos + 1;
2750 percpu_down_write(&file_rwsem);
2751 spin_lock(&blocked_lock_lock);
2752 return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
2755 static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2757 struct locks_iterator *iter = f->private;
2760 return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
2763 static void locks_stop(struct seq_file *f, void *v)
2764 __releases(&blocked_lock_lock)
2766 spin_unlock(&blocked_lock_lock);
2767 percpu_up_write(&file_rwsem);
2770 static const struct seq_operations locks_seq_operations = {
2771 .start = locks_start,
2777 static int locks_open(struct inode *inode, struct file *filp)
2779 return seq_open_private(filp, &locks_seq_operations,
2780 sizeof(struct locks_iterator));
2783 static const struct file_operations proc_locks_operations = {
2786 .llseek = seq_lseek,
2787 .release = seq_release_private,
2790 static int __init proc_locks_init(void)
2792 proc_create("locks", 0, NULL, &proc_locks_operations);
2795 fs_initcall(proc_locks_init);
2798 static int __init filelock_init(void)
2802 flctx_cache = kmem_cache_create("file_lock_ctx",
2803 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2805 filelock_cache = kmem_cache_create("file_lock_cache",
2806 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2809 for_each_possible_cpu(i) {
2810 struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
2812 spin_lock_init(&fll->lock);
2813 INIT_HLIST_HEAD(&fll->hlist);
2819 core_initcall(filelock_init);