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.
116 * Locking conflicts and dependencies:
117 * If multiple threads attempt to lock the same byte (or flock the same file)
118 * only one can be granted the lock, and other must wait their turn.
119 * The first lock has been "applied" or "granted", the others are "waiting"
120 * and are "blocked" by the "applied" lock..
122 * Waiting and applied locks are all kept in trees whose properties are:
124 * - the root of a tree may be an applied or waiting lock.
125 * - every other node in the tree is a waiting lock that
126 * conflicts with every ancestor of that node.
128 * Every such tree begins life as a waiting singleton which obviously
129 * satisfies the above properties.
131 * The only ways we modify trees preserve these properties:
133 * 1. We may add a new leaf node, but only after first verifying that it
134 * conflicts with all of its ancestors.
135 * 2. We may remove the root of a tree, creating a new singleton
136 * tree from the root and N new trees rooted in the immediate
138 * 3. If the root of a tree is not currently an applied lock, we may
139 * apply it (if possible).
140 * 4. We may upgrade the root of the tree (either extend its range,
141 * or upgrade its entire range from read to write).
143 * When an applied lock is modified in a way that reduces or downgrades any
144 * part of its range, we remove all its children (2 above). This particularly
145 * happens when a lock is unlocked.
147 * For each of those child trees we "wake up" the thread which is
148 * waiting for the lock so it can continue handling as follows: if the
149 * root of the tree applies, we do so (3). If it doesn't, it must
150 * conflict with some applied lock. We remove (wake up) all of its children
151 * (2), and add it is a new leaf to the tree rooted in the applied
152 * lock (1). We then repeat the process recursively with those
157 #include <linux/capability.h>
158 #include <linux/file.h>
159 #include <linux/fdtable.h>
160 #include <linux/fs.h>
161 #include <linux/init.h>
162 #include <linux/security.h>
163 #include <linux/slab.h>
164 #include <linux/syscalls.h>
165 #include <linux/time.h>
166 #include <linux/rcupdate.h>
167 #include <linux/pid_namespace.h>
168 #include <linux/hashtable.h>
169 #include <linux/percpu.h>
171 #define CREATE_TRACE_POINTS
172 #include <trace/events/filelock.h>
174 #include <linux/uaccess.h>
176 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
177 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
178 #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
179 #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
180 #define IS_REMOTELCK(fl) (fl->fl_pid <= 0)
182 static bool lease_breaking(struct file_lock *fl)
184 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
187 static int target_leasetype(struct file_lock *fl)
189 if (fl->fl_flags & FL_UNLOCK_PENDING)
191 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
196 int leases_enable = 1;
197 int lease_break_time = 45;
200 * The global file_lock_list is only used for displaying /proc/locks, so we
201 * keep a list on each CPU, with each list protected by its own spinlock.
202 * Global serialization is done using file_rwsem.
204 * Note that alterations to the list also require that the relevant flc_lock is
207 struct file_lock_list_struct {
209 struct hlist_head hlist;
211 static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
212 DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
215 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
216 * It is protected by blocked_lock_lock.
218 * We hash locks by lockowner in order to optimize searching for the lock a
219 * particular lockowner is waiting on.
221 * FIXME: make this value scale via some heuristic? We generally will want more
222 * buckets when we have more lockowners holding locks, but that's a little
223 * difficult to determine without knowing what the workload will look like.
225 #define BLOCKED_HASH_BITS 7
226 static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
229 * This lock protects the blocked_hash. Generally, if you're accessing it, you
230 * want to be holding this lock.
232 * In addition, it also protects the fl->fl_blocked_requests list, and the
233 * fl->fl_blocker pointer for file_lock structures that are acting as lock
234 * requests (in contrast to those that are acting as records of acquired locks).
236 * Note that when we acquire this lock in order to change the above fields,
237 * we often hold the flc_lock as well. In certain cases, when reading the fields
238 * protected by this lock, we can skip acquiring it iff we already hold the
241 static DEFINE_SPINLOCK(blocked_lock_lock);
243 static struct kmem_cache *flctx_cache __read_mostly;
244 static struct kmem_cache *filelock_cache __read_mostly;
246 static struct file_lock_context *
247 locks_get_lock_context(struct inode *inode, int type)
249 struct file_lock_context *ctx;
251 /* paired with cmpxchg() below */
252 ctx = smp_load_acquire(&inode->i_flctx);
253 if (likely(ctx) || type == F_UNLCK)
256 ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
260 spin_lock_init(&ctx->flc_lock);
261 INIT_LIST_HEAD(&ctx->flc_flock);
262 INIT_LIST_HEAD(&ctx->flc_posix);
263 INIT_LIST_HEAD(&ctx->flc_lease);
266 * Assign the pointer if it's not already assigned. If it is, then
267 * free the context we just allocated.
269 if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
270 kmem_cache_free(flctx_cache, ctx);
271 ctx = smp_load_acquire(&inode->i_flctx);
274 trace_locks_get_lock_context(inode, type, ctx);
279 locks_dump_ctx_list(struct list_head *list, char *list_type)
281 struct file_lock *fl;
283 list_for_each_entry(fl, list, fl_list) {
284 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);
289 locks_check_ctx_lists(struct inode *inode)
291 struct file_lock_context *ctx = inode->i_flctx;
293 if (unlikely(!list_empty(&ctx->flc_flock) ||
294 !list_empty(&ctx->flc_posix) ||
295 !list_empty(&ctx->flc_lease))) {
296 pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
297 MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
299 locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
300 locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
301 locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
306 locks_check_ctx_file_list(struct file *filp, struct list_head *list,
309 struct file_lock *fl;
310 struct inode *inode = locks_inode(filp);
312 list_for_each_entry(fl, list, fl_list)
313 if (fl->fl_file == filp)
314 pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%lx "
315 " fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
316 list_type, MAJOR(inode->i_sb->s_dev),
317 MINOR(inode->i_sb->s_dev), inode->i_ino,
318 fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
322 locks_free_lock_context(struct inode *inode)
324 struct file_lock_context *ctx = inode->i_flctx;
327 locks_check_ctx_lists(inode);
328 kmem_cache_free(flctx_cache, ctx);
332 static void locks_init_lock_heads(struct file_lock *fl)
334 INIT_HLIST_NODE(&fl->fl_link);
335 INIT_LIST_HEAD(&fl->fl_list);
336 INIT_LIST_HEAD(&fl->fl_blocked_requests);
337 INIT_LIST_HEAD(&fl->fl_blocked_member);
338 init_waitqueue_head(&fl->fl_wait);
341 /* Allocate an empty lock structure. */
342 struct file_lock *locks_alloc_lock(void)
344 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
347 locks_init_lock_heads(fl);
351 EXPORT_SYMBOL_GPL(locks_alloc_lock);
353 void locks_release_private(struct file_lock *fl)
355 BUG_ON(waitqueue_active(&fl->fl_wait));
356 BUG_ON(!list_empty(&fl->fl_list));
357 BUG_ON(!list_empty(&fl->fl_blocked_requests));
358 BUG_ON(!list_empty(&fl->fl_blocked_member));
359 BUG_ON(!hlist_unhashed(&fl->fl_link));
362 if (fl->fl_ops->fl_release_private)
363 fl->fl_ops->fl_release_private(fl);
368 if (fl->fl_lmops->lm_put_owner) {
369 fl->fl_lmops->lm_put_owner(fl->fl_owner);
375 EXPORT_SYMBOL_GPL(locks_release_private);
377 /* Free a lock which is not in use. */
378 void locks_free_lock(struct file_lock *fl)
380 locks_release_private(fl);
381 kmem_cache_free(filelock_cache, fl);
383 EXPORT_SYMBOL(locks_free_lock);
386 locks_dispose_list(struct list_head *dispose)
388 struct file_lock *fl;
390 while (!list_empty(dispose)) {
391 fl = list_first_entry(dispose, struct file_lock, fl_list);
392 list_del_init(&fl->fl_list);
397 void locks_init_lock(struct file_lock *fl)
399 memset(fl, 0, sizeof(struct file_lock));
400 locks_init_lock_heads(fl);
402 EXPORT_SYMBOL(locks_init_lock);
405 * Initialize a new lock from an existing file_lock structure.
407 void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
409 new->fl_owner = fl->fl_owner;
410 new->fl_pid = fl->fl_pid;
412 new->fl_flags = fl->fl_flags;
413 new->fl_type = fl->fl_type;
414 new->fl_start = fl->fl_start;
415 new->fl_end = fl->fl_end;
416 new->fl_lmops = fl->fl_lmops;
420 if (fl->fl_lmops->lm_get_owner)
421 fl->fl_lmops->lm_get_owner(fl->fl_owner);
424 EXPORT_SYMBOL(locks_copy_conflock);
426 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
428 /* "new" must be a freshly-initialized lock */
429 WARN_ON_ONCE(new->fl_ops);
431 locks_copy_conflock(new, fl);
433 new->fl_file = fl->fl_file;
434 new->fl_ops = fl->fl_ops;
437 if (fl->fl_ops->fl_copy_lock)
438 fl->fl_ops->fl_copy_lock(new, fl);
441 EXPORT_SYMBOL(locks_copy_lock);
443 static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
448 * As ctx->flc_lock is held, new requests cannot be added to
449 * ->fl_blocked_requests, so we don't need a lock to check if it
452 if (list_empty(&fl->fl_blocked_requests))
454 spin_lock(&blocked_lock_lock);
455 list_splice_init(&fl->fl_blocked_requests, &new->fl_blocked_requests);
456 list_for_each_entry(f, &new->fl_blocked_requests, fl_blocked_member)
458 spin_unlock(&blocked_lock_lock);
461 static inline int flock_translate_cmd(int cmd) {
463 return cmd & (LOCK_MAND | LOCK_RW);
475 /* Fill in a file_lock structure with an appropriate FLOCK lock. */
476 static struct file_lock *
477 flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
479 int type = flock_translate_cmd(cmd);
482 return ERR_PTR(type);
485 fl = locks_alloc_lock();
487 return ERR_PTR(-ENOMEM);
494 fl->fl_pid = current->tgid;
495 fl->fl_flags = FL_FLOCK;
497 fl->fl_end = OFFSET_MAX;
502 static int assign_type(struct file_lock *fl, long type)
516 static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
519 switch (l->l_whence) {
524 fl->fl_start = filp->f_pos;
527 fl->fl_start = i_size_read(file_inode(filp));
532 if (l->l_start > OFFSET_MAX - fl->fl_start)
534 fl->fl_start += l->l_start;
535 if (fl->fl_start < 0)
538 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
539 POSIX-2001 defines it. */
541 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
543 fl->fl_end = fl->fl_start + l->l_len - 1;
545 } else if (l->l_len < 0) {
546 if (fl->fl_start + l->l_len < 0)
548 fl->fl_end = fl->fl_start - 1;
549 fl->fl_start += l->l_len;
551 fl->fl_end = OFFSET_MAX;
553 fl->fl_owner = current->files;
554 fl->fl_pid = current->tgid;
556 fl->fl_flags = FL_POSIX;
560 return assign_type(fl, l->l_type);
563 /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
566 static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
569 struct flock64 ll = {
571 .l_whence = l->l_whence,
572 .l_start = l->l_start,
576 return flock64_to_posix_lock(filp, fl, &ll);
579 /* default lease lock manager operations */
581 lease_break_callback(struct file_lock *fl)
583 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
588 lease_setup(struct file_lock *fl, void **priv)
590 struct file *filp = fl->fl_file;
591 struct fasync_struct *fa = *priv;
594 * fasync_insert_entry() returns the old entry if any. If there was no
595 * old entry, then it used "priv" and inserted it into the fasync list.
596 * Clear the pointer to indicate that it shouldn't be freed.
598 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
601 __f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
604 static const struct lock_manager_operations lease_manager_ops = {
605 .lm_break = lease_break_callback,
606 .lm_change = lease_modify,
607 .lm_setup = lease_setup,
611 * Initialize a lease, use the default lock manager operations
613 static int lease_init(struct file *filp, long type, struct file_lock *fl)
615 if (assign_type(fl, type) != 0)
619 fl->fl_pid = current->tgid;
622 fl->fl_flags = FL_LEASE;
624 fl->fl_end = OFFSET_MAX;
626 fl->fl_lmops = &lease_manager_ops;
630 /* Allocate a file_lock initialised to this type of lease */
631 static struct file_lock *lease_alloc(struct file *filp, long type)
633 struct file_lock *fl = locks_alloc_lock();
637 return ERR_PTR(error);
639 error = lease_init(filp, type, fl);
642 return ERR_PTR(error);
647 /* Check if two locks overlap each other.
649 static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
651 return ((fl1->fl_end >= fl2->fl_start) &&
652 (fl2->fl_end >= fl1->fl_start));
656 * Check whether two locks have the same owner.
658 static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
660 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
661 return fl2->fl_lmops == fl1->fl_lmops &&
662 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
663 return fl1->fl_owner == fl2->fl_owner;
666 /* Must be called with the flc_lock held! */
667 static void locks_insert_global_locks(struct file_lock *fl)
669 struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
671 percpu_rwsem_assert_held(&file_rwsem);
673 spin_lock(&fll->lock);
674 fl->fl_link_cpu = smp_processor_id();
675 hlist_add_head(&fl->fl_link, &fll->hlist);
676 spin_unlock(&fll->lock);
679 /* Must be called with the flc_lock held! */
680 static void locks_delete_global_locks(struct file_lock *fl)
682 struct file_lock_list_struct *fll;
684 percpu_rwsem_assert_held(&file_rwsem);
687 * Avoid taking lock if already unhashed. This is safe since this check
688 * is done while holding the flc_lock, and new insertions into the list
689 * also require that it be held.
691 if (hlist_unhashed(&fl->fl_link))
694 fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
695 spin_lock(&fll->lock);
696 hlist_del_init(&fl->fl_link);
697 spin_unlock(&fll->lock);
701 posix_owner_key(struct file_lock *fl)
703 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
704 return fl->fl_lmops->lm_owner_key(fl);
705 return (unsigned long)fl->fl_owner;
708 static void locks_insert_global_blocked(struct file_lock *waiter)
710 lockdep_assert_held(&blocked_lock_lock);
712 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
715 static void locks_delete_global_blocked(struct file_lock *waiter)
717 lockdep_assert_held(&blocked_lock_lock);
719 hash_del(&waiter->fl_link);
722 /* Remove waiter from blocker's block list.
723 * When blocker ends up pointing to itself then the list is empty.
725 * Must be called with blocked_lock_lock held.
727 static void __locks_delete_block(struct file_lock *waiter)
729 locks_delete_global_blocked(waiter);
730 list_del_init(&waiter->fl_blocked_member);
731 waiter->fl_blocker = NULL;
734 static void __locks_wake_up_blocks(struct file_lock *blocker)
736 while (!list_empty(&blocker->fl_blocked_requests)) {
737 struct file_lock *waiter;
739 waiter = list_first_entry(&blocker->fl_blocked_requests,
740 struct file_lock, fl_blocked_member);
741 __locks_delete_block(waiter);
742 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
743 waiter->fl_lmops->lm_notify(waiter);
745 wake_up(&waiter->fl_wait);
750 * locks_delete_lock - stop waiting for a file lock
751 * @waiter: the lock which was waiting
753 * lockd/nfsd need to disconnect the lock while working on it.
755 int locks_delete_block(struct file_lock *waiter)
757 int status = -ENOENT;
760 * If fl_blocker is NULL, it won't be set again as this thread
761 * "owns" the lock and is the only one that might try to claim
762 * the lock. So it is safe to test fl_blocker locklessly.
763 * Also if fl_blocker is NULL, this waiter is not listed on
764 * fl_blocked_requests for some lock, so no other request can
765 * be added to the list of fl_blocked_requests for this
766 * request. So if fl_blocker is NULL, it is safe to
767 * locklessly check if fl_blocked_requests is empty. If both
768 * of these checks succeed, there is no need to take the lock.
770 if (waiter->fl_blocker == NULL &&
771 list_empty(&waiter->fl_blocked_requests))
773 spin_lock(&blocked_lock_lock);
774 if (waiter->fl_blocker)
776 __locks_wake_up_blocks(waiter);
777 __locks_delete_block(waiter);
778 spin_unlock(&blocked_lock_lock);
781 EXPORT_SYMBOL(locks_delete_block);
783 /* Insert waiter into blocker's block list.
784 * We use a circular list so that processes can be easily woken up in
785 * the order they blocked. The documentation doesn't require this but
786 * it seems like the reasonable thing to do.
788 * Must be called with both the flc_lock and blocked_lock_lock held. The
789 * fl_blocked_requests list itself is protected by the blocked_lock_lock,
790 * but by ensuring that the flc_lock is also held on insertions we can avoid
791 * taking the blocked_lock_lock in some cases when we see that the
792 * fl_blocked_requests list is empty.
794 * Rather than just adding to the list, we check for conflicts with any existing
795 * waiters, and add beneath any waiter that blocks the new waiter.
796 * Thus wakeups don't happen until needed.
798 static void __locks_insert_block(struct file_lock *blocker,
799 struct file_lock *waiter,
800 bool conflict(struct file_lock *,
803 struct file_lock *fl;
804 BUG_ON(!list_empty(&waiter->fl_blocked_member));
807 list_for_each_entry(fl, &blocker->fl_blocked_requests, fl_blocked_member)
808 if (conflict(fl, waiter)) {
812 waiter->fl_blocker = blocker;
813 list_add_tail(&waiter->fl_blocked_member, &blocker->fl_blocked_requests);
814 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
815 locks_insert_global_blocked(waiter);
817 /* The requests in waiter->fl_blocked are known to conflict with
818 * waiter, but might not conflict with blocker, or the requests
819 * and lock which block it. So they all need to be woken.
821 __locks_wake_up_blocks(waiter);
824 /* Must be called with flc_lock held. */
825 static void locks_insert_block(struct file_lock *blocker,
826 struct file_lock *waiter,
827 bool conflict(struct file_lock *,
830 spin_lock(&blocked_lock_lock);
831 __locks_insert_block(blocker, waiter, conflict);
832 spin_unlock(&blocked_lock_lock);
836 * Wake up processes blocked waiting for blocker.
838 * Must be called with the inode->flc_lock held!
840 static void locks_wake_up_blocks(struct file_lock *blocker)
843 * Avoid taking global lock if list is empty. This is safe since new
844 * blocked requests are only added to the list under the flc_lock, and
845 * the flc_lock is always held here. Note that removal from the
846 * fl_blocked_requests list does not require the flc_lock, so we must
847 * recheck list_empty() after acquiring the blocked_lock_lock.
849 if (list_empty(&blocker->fl_blocked_requests))
852 spin_lock(&blocked_lock_lock);
853 __locks_wake_up_blocks(blocker);
854 spin_unlock(&blocked_lock_lock);
858 locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
860 list_add_tail(&fl->fl_list, before);
861 locks_insert_global_locks(fl);
865 locks_unlink_lock_ctx(struct file_lock *fl)
867 locks_delete_global_locks(fl);
868 list_del_init(&fl->fl_list);
869 locks_wake_up_blocks(fl);
873 locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
875 locks_unlink_lock_ctx(fl);
877 list_add(&fl->fl_list, dispose);
882 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
883 * checks for shared/exclusive status of overlapping locks.
885 static bool locks_conflict(struct file_lock *caller_fl,
886 struct file_lock *sys_fl)
888 if (sys_fl->fl_type == F_WRLCK)
890 if (caller_fl->fl_type == F_WRLCK)
895 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
896 * checking before calling the locks_conflict().
898 static bool posix_locks_conflict(struct file_lock *caller_fl,
899 struct file_lock *sys_fl)
901 /* POSIX locks owned by the same process do not conflict with
904 if (posix_same_owner(caller_fl, sys_fl))
907 /* Check whether they overlap */
908 if (!locks_overlap(caller_fl, sys_fl))
911 return locks_conflict(caller_fl, sys_fl);
914 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
915 * checking before calling the locks_conflict().
917 static bool flock_locks_conflict(struct file_lock *caller_fl,
918 struct file_lock *sys_fl)
920 /* FLOCK locks referring to the same filp do not conflict with
923 if (caller_fl->fl_file == sys_fl->fl_file)
925 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
928 return locks_conflict(caller_fl, sys_fl);
932 posix_test_lock(struct file *filp, struct file_lock *fl)
934 struct file_lock *cfl;
935 struct file_lock_context *ctx;
936 struct inode *inode = locks_inode(filp);
938 ctx = smp_load_acquire(&inode->i_flctx);
939 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
940 fl->fl_type = F_UNLCK;
944 spin_lock(&ctx->flc_lock);
945 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
946 if (posix_locks_conflict(fl, cfl)) {
947 locks_copy_conflock(fl, cfl);
951 fl->fl_type = F_UNLCK;
953 spin_unlock(&ctx->flc_lock);
956 EXPORT_SYMBOL(posix_test_lock);
959 * Deadlock detection:
961 * We attempt to detect deadlocks that are due purely to posix file
964 * We assume that a task can be waiting for at most one lock at a time.
965 * So for any acquired lock, the process holding that lock may be
966 * waiting on at most one other lock. That lock in turns may be held by
967 * someone waiting for at most one other lock. Given a requested lock
968 * caller_fl which is about to wait for a conflicting lock block_fl, we
969 * follow this chain of waiters to ensure we are not about to create a
972 * Since we do this before we ever put a process to sleep on a lock, we
973 * are ensured that there is never a cycle; that is what guarantees that
974 * the while() loop in posix_locks_deadlock() eventually completes.
976 * Note: the above assumption may not be true when handling lock
977 * requests from a broken NFS client. It may also fail in the presence
978 * of tasks (such as posix threads) sharing the same open file table.
979 * To handle those cases, we just bail out after a few iterations.
981 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
982 * Because the owner is not even nominally tied to a thread of
983 * execution, the deadlock detection below can't reasonably work well. Just
986 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
987 * locks that just checks for the case where two tasks are attempting to
988 * upgrade from read to write locks on the same inode.
991 #define MAX_DEADLK_ITERATIONS 10
993 /* Find a lock that the owner of the given block_fl is blocking on. */
994 static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
996 struct file_lock *fl;
998 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
999 if (posix_same_owner(fl, block_fl)) {
1000 while (fl->fl_blocker)
1001 fl = fl->fl_blocker;
1008 /* Must be called with the blocked_lock_lock held! */
1009 static int posix_locks_deadlock(struct file_lock *caller_fl,
1010 struct file_lock *block_fl)
1014 lockdep_assert_held(&blocked_lock_lock);
1017 * This deadlock detector can't reasonably detect deadlocks with
1018 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
1020 if (IS_OFDLCK(caller_fl))
1023 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
1024 if (i++ > MAX_DEADLK_ITERATIONS)
1026 if (posix_same_owner(caller_fl, block_fl))
1032 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
1033 * after any leases, but before any posix locks.
1035 * Note that if called with an FL_EXISTS argument, the caller may determine
1036 * whether or not a lock was successfully freed by testing the return
1037 * value for -ENOENT.
1039 static int flock_lock_inode(struct inode *inode, struct file_lock *request)
1041 struct file_lock *new_fl = NULL;
1042 struct file_lock *fl;
1043 struct file_lock_context *ctx;
1048 ctx = locks_get_lock_context(inode, request->fl_type);
1050 if (request->fl_type != F_UNLCK)
1052 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
1055 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
1056 new_fl = locks_alloc_lock();
1061 percpu_down_read(&file_rwsem);
1062 spin_lock(&ctx->flc_lock);
1063 if (request->fl_flags & FL_ACCESS)
1066 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
1067 if (request->fl_file != fl->fl_file)
1069 if (request->fl_type == fl->fl_type)
1072 locks_delete_lock_ctx(fl, &dispose);
1076 if (request->fl_type == F_UNLCK) {
1077 if ((request->fl_flags & FL_EXISTS) && !found)
1083 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
1084 if (!flock_locks_conflict(request, fl))
1087 if (!(request->fl_flags & FL_SLEEP))
1089 error = FILE_LOCK_DEFERRED;
1090 locks_insert_block(fl, request, flock_locks_conflict);
1093 if (request->fl_flags & FL_ACCESS)
1095 locks_copy_lock(new_fl, request);
1096 locks_move_blocks(new_fl, request);
1097 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
1102 spin_unlock(&ctx->flc_lock);
1103 percpu_up_read(&file_rwsem);
1105 locks_free_lock(new_fl);
1106 locks_dispose_list(&dispose);
1107 trace_flock_lock_inode(inode, request, error);
1111 static int posix_lock_inode(struct inode *inode, struct file_lock *request,
1112 struct file_lock *conflock)
1114 struct file_lock *fl, *tmp;
1115 struct file_lock *new_fl = NULL;
1116 struct file_lock *new_fl2 = NULL;
1117 struct file_lock *left = NULL;
1118 struct file_lock *right = NULL;
1119 struct file_lock_context *ctx;
1124 ctx = locks_get_lock_context(inode, request->fl_type);
1126 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
1129 * We may need two file_lock structures for this operation,
1130 * so we get them in advance to avoid races.
1132 * In some cases we can be sure, that no new locks will be needed
1134 if (!(request->fl_flags & FL_ACCESS) &&
1135 (request->fl_type != F_UNLCK ||
1136 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1137 new_fl = locks_alloc_lock();
1138 new_fl2 = locks_alloc_lock();
1141 percpu_down_read(&file_rwsem);
1142 spin_lock(&ctx->flc_lock);
1144 * New lock request. Walk all POSIX locks and look for conflicts. If
1145 * there are any, either return error or put the request on the
1146 * blocker's list of waiters and the global blocked_hash.
1148 if (request->fl_type != F_UNLCK) {
1149 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1150 if (!posix_locks_conflict(request, fl))
1153 locks_copy_conflock(conflock, fl);
1155 if (!(request->fl_flags & FL_SLEEP))
1158 * Deadlock detection and insertion into the blocked
1159 * locks list must be done while holding the same lock!
1162 spin_lock(&blocked_lock_lock);
1164 * Ensure that we don't find any locks blocked on this
1165 * request during deadlock detection.
1167 __locks_wake_up_blocks(request);
1168 if (likely(!posix_locks_deadlock(request, fl))) {
1169 error = FILE_LOCK_DEFERRED;
1170 __locks_insert_block(fl, request,
1171 posix_locks_conflict);
1173 spin_unlock(&blocked_lock_lock);
1178 /* If we're just looking for a conflict, we're done. */
1180 if (request->fl_flags & FL_ACCESS)
1183 /* Find the first old lock with the same owner as the new lock */
1184 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1185 if (posix_same_owner(request, fl))
1189 /* Process locks with this owner. */
1190 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1191 if (!posix_same_owner(request, fl))
1194 /* Detect adjacent or overlapping regions (if same lock type) */
1195 if (request->fl_type == fl->fl_type) {
1196 /* In all comparisons of start vs end, use
1197 * "start - 1" rather than "end + 1". If end
1198 * is OFFSET_MAX, end + 1 will become negative.
1200 if (fl->fl_end < request->fl_start - 1)
1202 /* If the next lock in the list has entirely bigger
1203 * addresses than the new one, insert the lock here.
1205 if (fl->fl_start - 1 > request->fl_end)
1208 /* If we come here, the new and old lock are of the
1209 * same type and adjacent or overlapping. Make one
1210 * lock yielding from the lower start address of both
1211 * locks to the higher end address.
1213 if (fl->fl_start > request->fl_start)
1214 fl->fl_start = request->fl_start;
1216 request->fl_start = fl->fl_start;
1217 if (fl->fl_end < request->fl_end)
1218 fl->fl_end = request->fl_end;
1220 request->fl_end = fl->fl_end;
1222 locks_delete_lock_ctx(fl, &dispose);
1228 /* Processing for different lock types is a bit
1231 if (fl->fl_end < request->fl_start)
1233 if (fl->fl_start > request->fl_end)
1235 if (request->fl_type == F_UNLCK)
1237 if (fl->fl_start < request->fl_start)
1239 /* If the next lock in the list has a higher end
1240 * address than the new one, insert the new one here.
1242 if (fl->fl_end > request->fl_end) {
1246 if (fl->fl_start >= request->fl_start) {
1247 /* The new lock completely replaces an old
1248 * one (This may happen several times).
1251 locks_delete_lock_ctx(fl, &dispose);
1255 * Replace the old lock with new_fl, and
1256 * remove the old one. It's safe to do the
1257 * insert here since we know that we won't be
1258 * using new_fl later, and that the lock is
1259 * just replacing an existing lock.
1264 locks_copy_lock(new_fl, request);
1267 locks_insert_lock_ctx(request, &fl->fl_list);
1268 locks_delete_lock_ctx(fl, &dispose);
1275 * The above code only modifies existing locks in case of merging or
1276 * replacing. If new lock(s) need to be inserted all modifications are
1277 * done below this, so it's safe yet to bail out.
1279 error = -ENOLCK; /* "no luck" */
1280 if (right && left == right && !new_fl2)
1285 if (request->fl_type == F_UNLCK) {
1286 if (request->fl_flags & FL_EXISTS)
1295 locks_copy_lock(new_fl, request);
1296 locks_move_blocks(new_fl, request);
1297 locks_insert_lock_ctx(new_fl, &fl->fl_list);
1302 if (left == right) {
1303 /* The new lock breaks the old one in two pieces,
1304 * so we have to use the second new lock.
1308 locks_copy_lock(left, right);
1309 locks_insert_lock_ctx(left, &fl->fl_list);
1311 right->fl_start = request->fl_end + 1;
1312 locks_wake_up_blocks(right);
1315 left->fl_end = request->fl_start - 1;
1316 locks_wake_up_blocks(left);
1319 spin_unlock(&ctx->flc_lock);
1320 percpu_up_read(&file_rwsem);
1322 * Free any unused locks.
1325 locks_free_lock(new_fl);
1327 locks_free_lock(new_fl2);
1328 locks_dispose_list(&dispose);
1329 trace_posix_lock_inode(inode, request, error);
1335 * posix_lock_file - Apply a POSIX-style lock to a file
1336 * @filp: The file to apply the lock to
1337 * @fl: The lock to be applied
1338 * @conflock: Place to return a copy of the conflicting lock, if found.
1340 * Add a POSIX style lock to a file.
1341 * We merge adjacent & overlapping locks whenever possible.
1342 * POSIX locks are sorted by owner task, then by starting address
1344 * Note that if called with an FL_EXISTS argument, the caller may determine
1345 * whether or not a lock was successfully freed by testing the return
1346 * value for -ENOENT.
1348 int posix_lock_file(struct file *filp, struct file_lock *fl,
1349 struct file_lock *conflock)
1351 return posix_lock_inode(locks_inode(filp), fl, conflock);
1353 EXPORT_SYMBOL(posix_lock_file);
1356 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1357 * @inode: inode of file to which lock request should be applied
1358 * @fl: The lock to be applied
1360 * Apply a POSIX style lock request to an inode.
1362 static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1367 error = posix_lock_inode(inode, fl, NULL);
1368 if (error != FILE_LOCK_DEFERRED)
1370 error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker);
1374 locks_delete_block(fl);
1378 #ifdef CONFIG_MANDATORY_FILE_LOCKING
1380 * locks_mandatory_locked - Check for an active lock
1381 * @file: the file to check
1383 * Searches the inode's list of locks to find any POSIX locks which conflict.
1384 * This function is called from locks_verify_locked() only.
1386 int locks_mandatory_locked(struct file *file)
1389 struct inode *inode = locks_inode(file);
1390 struct file_lock_context *ctx;
1391 struct file_lock *fl;
1393 ctx = smp_load_acquire(&inode->i_flctx);
1394 if (!ctx || list_empty_careful(&ctx->flc_posix))
1398 * Search the lock list for this inode for any POSIX locks.
1400 spin_lock(&ctx->flc_lock);
1402 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1403 if (fl->fl_owner != current->files &&
1404 fl->fl_owner != file) {
1409 spin_unlock(&ctx->flc_lock);
1414 * locks_mandatory_area - Check for a conflicting lock
1415 * @inode: the file to check
1416 * @filp: how the file was opened (if it was)
1417 * @start: first byte in the file to check
1418 * @end: lastbyte in the file to check
1419 * @type: %F_WRLCK for a write lock, else %F_RDLCK
1421 * Searches the inode's list of locks to find any POSIX locks which conflict.
1423 int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1424 loff_t end, unsigned char type)
1426 struct file_lock fl;
1430 locks_init_lock(&fl);
1431 fl.fl_pid = current->tgid;
1433 fl.fl_flags = FL_POSIX | FL_ACCESS;
1434 if (filp && !(filp->f_flags & O_NONBLOCK))
1437 fl.fl_start = start;
1443 fl.fl_flags &= ~FL_SLEEP;
1444 error = posix_lock_inode(inode, &fl, NULL);
1450 fl.fl_flags |= FL_SLEEP;
1451 fl.fl_owner = current->files;
1452 error = posix_lock_inode(inode, &fl, NULL);
1453 if (error != FILE_LOCK_DEFERRED)
1455 error = wait_event_interruptible(fl.fl_wait, !fl.fl_blocker);
1458 * If we've been sleeping someone might have
1459 * changed the permissions behind our back.
1461 if (__mandatory_lock(inode))
1467 locks_delete_block(&fl);
1471 EXPORT_SYMBOL(locks_mandatory_area);
1472 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
1474 static void lease_clear_pending(struct file_lock *fl, int arg)
1478 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1481 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1485 /* We already had a lease on this file; just change its type */
1486 int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
1488 int error = assign_type(fl, arg);
1492 lease_clear_pending(fl, arg);
1493 locks_wake_up_blocks(fl);
1494 if (arg == F_UNLCK) {
1495 struct file *filp = fl->fl_file;
1498 filp->f_owner.signum = 0;
1499 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1500 if (fl->fl_fasync != NULL) {
1501 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1502 fl->fl_fasync = NULL;
1504 locks_delete_lock_ctx(fl, dispose);
1508 EXPORT_SYMBOL(lease_modify);
1510 static bool past_time(unsigned long then)
1513 /* 0 is a special value meaning "this never expires": */
1515 return time_after(jiffies, then);
1518 static void time_out_leases(struct inode *inode, struct list_head *dispose)
1520 struct file_lock_context *ctx = inode->i_flctx;
1521 struct file_lock *fl, *tmp;
1523 lockdep_assert_held(&ctx->flc_lock);
1525 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1526 trace_time_out_leases(inode, fl);
1527 if (past_time(fl->fl_downgrade_time))
1528 lease_modify(fl, F_RDLCK, dispose);
1529 if (past_time(fl->fl_break_time))
1530 lease_modify(fl, F_UNLCK, dispose);
1534 static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1536 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1538 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1540 return locks_conflict(breaker, lease);
1544 any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1546 struct file_lock_context *ctx = inode->i_flctx;
1547 struct file_lock *fl;
1549 lockdep_assert_held(&ctx->flc_lock);
1551 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1552 if (leases_conflict(fl, breaker))
1559 * __break_lease - revoke all outstanding leases on file
1560 * @inode: the inode of the file to return
1561 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1563 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1566 * break_lease (inlined for speed) has checked there already is at least
1567 * some kind of lock (maybe a lease) on this file. Leases are broken on
1568 * a call to open() or truncate(). This function can sleep unless you
1569 * specified %O_NONBLOCK to your open().
1571 int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1574 struct file_lock_context *ctx;
1575 struct file_lock *new_fl, *fl, *tmp;
1576 unsigned long break_time;
1577 int want_write = (mode & O_ACCMODE) != O_RDONLY;
1580 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1582 return PTR_ERR(new_fl);
1583 new_fl->fl_flags = type;
1585 /* typically we will check that ctx is non-NULL before calling */
1586 ctx = smp_load_acquire(&inode->i_flctx);
1592 percpu_down_read(&file_rwsem);
1593 spin_lock(&ctx->flc_lock);
1595 time_out_leases(inode, &dispose);
1597 if (!any_leases_conflict(inode, new_fl))
1601 if (lease_break_time > 0) {
1602 break_time = jiffies + lease_break_time * HZ;
1603 if (break_time == 0)
1604 break_time++; /* so that 0 means no break time */
1607 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1608 if (!leases_conflict(fl, new_fl))
1611 if (fl->fl_flags & FL_UNLOCK_PENDING)
1613 fl->fl_flags |= FL_UNLOCK_PENDING;
1614 fl->fl_break_time = break_time;
1616 if (lease_breaking(fl))
1618 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1619 fl->fl_downgrade_time = break_time;
1621 if (fl->fl_lmops->lm_break(fl))
1622 locks_delete_lock_ctx(fl, &dispose);
1625 if (list_empty(&ctx->flc_lease))
1628 if (mode & O_NONBLOCK) {
1629 trace_break_lease_noblock(inode, new_fl);
1630 error = -EWOULDBLOCK;
1635 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1636 break_time = fl->fl_break_time;
1637 if (break_time != 0)
1638 break_time -= jiffies;
1639 if (break_time == 0)
1641 locks_insert_block(fl, new_fl, leases_conflict);
1642 trace_break_lease_block(inode, new_fl);
1643 spin_unlock(&ctx->flc_lock);
1644 percpu_up_read(&file_rwsem);
1646 locks_dispose_list(&dispose);
1647 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1648 !new_fl->fl_blocker, break_time);
1650 percpu_down_read(&file_rwsem);
1651 spin_lock(&ctx->flc_lock);
1652 trace_break_lease_unblock(inode, new_fl);
1653 locks_delete_block(new_fl);
1656 * Wait for the next conflicting lease that has not been
1660 time_out_leases(inode, &dispose);
1661 if (any_leases_conflict(inode, new_fl))
1666 spin_unlock(&ctx->flc_lock);
1667 percpu_up_read(&file_rwsem);
1668 locks_dispose_list(&dispose);
1669 locks_free_lock(new_fl);
1672 EXPORT_SYMBOL(__break_lease);
1675 * lease_get_mtime - update modified time of an inode with exclusive lease
1677 * @time: pointer to a timespec which contains the last modified time
1679 * This is to force NFS clients to flush their caches for files with
1680 * exclusive leases. The justification is that if someone has an
1681 * exclusive lease, then they could be modifying it.
1683 void lease_get_mtime(struct inode *inode, struct timespec64 *time)
1685 bool has_lease = false;
1686 struct file_lock_context *ctx;
1687 struct file_lock *fl;
1689 ctx = smp_load_acquire(&inode->i_flctx);
1690 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1691 spin_lock(&ctx->flc_lock);
1692 fl = list_first_entry_or_null(&ctx->flc_lease,
1693 struct file_lock, fl_list);
1694 if (fl && (fl->fl_type == F_WRLCK))
1696 spin_unlock(&ctx->flc_lock);
1700 *time = current_time(inode);
1702 EXPORT_SYMBOL(lease_get_mtime);
1705 * fcntl_getlease - Enquire what lease is currently active
1708 * The value returned by this function will be one of
1709 * (if no lease break is pending):
1711 * %F_RDLCK to indicate a shared lease is held.
1713 * %F_WRLCK to indicate an exclusive lease is held.
1715 * %F_UNLCK to indicate no lease is held.
1717 * (if a lease break is pending):
1719 * %F_RDLCK to indicate an exclusive lease needs to be
1720 * changed to a shared lease (or removed).
1722 * %F_UNLCK to indicate the lease needs to be removed.
1724 * XXX: sfr & willy disagree over whether F_INPROGRESS
1725 * should be returned to userspace.
1727 int fcntl_getlease(struct file *filp)
1729 struct file_lock *fl;
1730 struct inode *inode = locks_inode(filp);
1731 struct file_lock_context *ctx;
1735 ctx = smp_load_acquire(&inode->i_flctx);
1736 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1737 percpu_down_read(&file_rwsem);
1738 spin_lock(&ctx->flc_lock);
1739 time_out_leases(inode, &dispose);
1740 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1741 if (fl->fl_file != filp)
1743 type = target_leasetype(fl);
1746 spin_unlock(&ctx->flc_lock);
1747 percpu_up_read(&file_rwsem);
1749 locks_dispose_list(&dispose);
1755 * check_conflicting_open - see if the given dentry points to a file that has
1756 * an existing open that would conflict with the
1758 * @dentry: dentry to check
1759 * @arg: type of lease that we're trying to acquire
1760 * @flags: current lock flags
1762 * Check to see if there's an existing open fd on this file that would
1763 * conflict with the lease we're trying to set.
1766 check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
1769 struct inode *inode = dentry->d_inode;
1771 if (flags & FL_LAYOUT)
1774 if ((arg == F_RDLCK) && inode_is_open_for_write(inode))
1777 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1778 (atomic_read(&inode->i_count) > 1)))
1785 generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1787 struct file_lock *fl, *my_fl = NULL, *lease;
1788 struct dentry *dentry = filp->f_path.dentry;
1789 struct inode *inode = dentry->d_inode;
1790 struct file_lock_context *ctx;
1791 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1796 trace_generic_add_lease(inode, lease);
1798 /* Note that arg is never F_UNLCK here */
1799 ctx = locks_get_lock_context(inode, arg);
1804 * In the delegation case we need mutual exclusion with
1805 * a number of operations that take the i_mutex. We trylock
1806 * because delegations are an optional optimization, and if
1807 * there's some chance of a conflict--we'd rather not
1808 * bother, maybe that's a sign this just isn't a good file to
1809 * hand out a delegation on.
1811 if (is_deleg && !inode_trylock(inode))
1814 if (is_deleg && arg == F_WRLCK) {
1815 /* Write delegations are not currently supported: */
1816 inode_unlock(inode);
1821 percpu_down_read(&file_rwsem);
1822 spin_lock(&ctx->flc_lock);
1823 time_out_leases(inode, &dispose);
1824 error = check_conflicting_open(dentry, arg, lease->fl_flags);
1829 * At this point, we know that if there is an exclusive
1830 * lease on this file, then we hold it on this filp
1831 * (otherwise our open of this file would have blocked).
1832 * And if we are trying to acquire an exclusive lease,
1833 * then the file is not open by anyone (including us)
1834 * except for this filp.
1837 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1838 if (fl->fl_file == filp &&
1839 fl->fl_owner == lease->fl_owner) {
1845 * No exclusive leases if someone else has a lease on
1851 * Modifying our existing lease is OK, but no getting a
1852 * new lease if someone else is opening for write:
1854 if (fl->fl_flags & FL_UNLOCK_PENDING)
1858 if (my_fl != NULL) {
1860 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
1870 locks_insert_lock_ctx(lease, &ctx->flc_lease);
1872 * The check in break_lease() is lockless. It's possible for another
1873 * open to race in after we did the earlier check for a conflicting
1874 * open but before the lease was inserted. Check again for a
1875 * conflicting open and cancel the lease if there is one.
1877 * We also add a barrier here to ensure that the insertion of the lock
1878 * precedes these checks.
1881 error = check_conflicting_open(dentry, arg, lease->fl_flags);
1883 locks_unlink_lock_ctx(lease);
1888 if (lease->fl_lmops->lm_setup)
1889 lease->fl_lmops->lm_setup(lease, priv);
1891 spin_unlock(&ctx->flc_lock);
1892 percpu_up_read(&file_rwsem);
1893 locks_dispose_list(&dispose);
1895 inode_unlock(inode);
1896 if (!error && !my_fl)
1901 static int generic_delete_lease(struct file *filp, void *owner)
1903 int error = -EAGAIN;
1904 struct file_lock *fl, *victim = NULL;
1905 struct inode *inode = locks_inode(filp);
1906 struct file_lock_context *ctx;
1909 ctx = smp_load_acquire(&inode->i_flctx);
1911 trace_generic_delete_lease(inode, NULL);
1915 percpu_down_read(&file_rwsem);
1916 spin_lock(&ctx->flc_lock);
1917 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1918 if (fl->fl_file == filp &&
1919 fl->fl_owner == owner) {
1924 trace_generic_delete_lease(inode, victim);
1926 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
1927 spin_unlock(&ctx->flc_lock);
1928 percpu_up_read(&file_rwsem);
1929 locks_dispose_list(&dispose);
1934 * generic_setlease - sets a lease on an open file
1935 * @filp: file pointer
1936 * @arg: type of lease to obtain
1937 * @flp: input - file_lock to use, output - file_lock inserted
1938 * @priv: private data for lm_setup (may be NULL if lm_setup
1939 * doesn't require it)
1941 * The (input) flp->fl_lmops->lm_break function is required
1944 int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1947 struct inode *inode = locks_inode(filp);
1950 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1952 if (!S_ISREG(inode->i_mode))
1954 error = security_file_lock(filp, arg);
1960 return generic_delete_lease(filp, *priv);
1963 if (!(*flp)->fl_lmops->lm_break) {
1968 return generic_add_lease(filp, arg, flp, priv);
1973 EXPORT_SYMBOL(generic_setlease);
1976 * vfs_setlease - sets a lease on an open file
1977 * @filp: file pointer
1978 * @arg: type of lease to obtain
1979 * @lease: file_lock to use when adding a lease
1980 * @priv: private info for lm_setup when adding a lease (may be
1981 * NULL if lm_setup doesn't require it)
1983 * Call this to establish a lease on the file. The "lease" argument is not
1984 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1985 * an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be
1986 * set; if not, this function will return -ENOLCK (and generate a scary-looking
1989 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1990 * may be NULL if the lm_setup operation doesn't require it.
1993 vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
1995 if (filp->f_op->setlease)
1996 return filp->f_op->setlease(filp, arg, lease, priv);
1998 return generic_setlease(filp, arg, lease, priv);
2000 EXPORT_SYMBOL_GPL(vfs_setlease);
2002 static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
2004 struct file_lock *fl;
2005 struct fasync_struct *new;
2008 fl = lease_alloc(filp, arg);
2012 new = fasync_alloc();
2014 locks_free_lock(fl);
2019 error = vfs_setlease(filp, arg, &fl, (void **)&new);
2021 locks_free_lock(fl);
2028 * fcntl_setlease - sets a lease on an open file
2029 * @fd: open file descriptor
2030 * @filp: file pointer
2031 * @arg: type of lease to obtain
2033 * Call this fcntl to establish a lease on the file.
2034 * Note that you also need to call %F_SETSIG to
2035 * receive a signal when the lease is broken.
2037 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
2040 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
2041 return do_fcntl_add_lease(fd, filp, arg);
2045 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
2046 * @inode: inode of the file to apply to
2047 * @fl: The lock to be applied
2049 * Apply a FLOCK style lock request to an inode.
2051 static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
2056 error = flock_lock_inode(inode, fl);
2057 if (error != FILE_LOCK_DEFERRED)
2059 error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker);
2063 locks_delete_block(fl);
2068 * locks_lock_inode_wait - Apply a lock to an inode
2069 * @inode: inode of the file to apply to
2070 * @fl: The lock to be applied
2072 * Apply a POSIX or FLOCK style lock request to an inode.
2074 int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
2077 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
2079 res = posix_lock_inode_wait(inode, fl);
2082 res = flock_lock_inode_wait(inode, fl);
2089 EXPORT_SYMBOL(locks_lock_inode_wait);
2092 * sys_flock: - flock() system call.
2093 * @fd: the file descriptor to lock.
2094 * @cmd: the type of lock to apply.
2096 * Apply a %FL_FLOCK style lock to an open file descriptor.
2097 * The @cmd can be one of:
2099 * - %LOCK_SH -- a shared lock.
2100 * - %LOCK_EX -- an exclusive lock.
2101 * - %LOCK_UN -- remove an existing lock.
2102 * - %LOCK_MAND -- a 'mandatory' flock.
2103 * This exists to emulate Windows Share Modes.
2105 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
2106 * processes read and write access respectively.
2108 SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
2110 struct fd f = fdget(fd);
2111 struct file_lock *lock;
2112 int can_sleep, unlock;
2119 can_sleep = !(cmd & LOCK_NB);
2121 unlock = (cmd == LOCK_UN);
2123 if (!unlock && !(cmd & LOCK_MAND) &&
2124 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
2127 lock = flock_make_lock(f.file, cmd, NULL);
2129 error = PTR_ERR(lock);
2134 lock->fl_flags |= FL_SLEEP;
2136 error = security_file_lock(f.file, lock->fl_type);
2140 if (f.file->f_op->flock)
2141 error = f.file->f_op->flock(f.file,
2142 (can_sleep) ? F_SETLKW : F_SETLK,
2145 error = locks_lock_file_wait(f.file, lock);
2148 locks_free_lock(lock);
2157 * vfs_test_lock - test file byte range lock
2158 * @filp: The file to test lock for
2159 * @fl: The lock to test; also used to hold result
2161 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2162 * setting conf->fl_type to something other than F_UNLCK.
2164 int vfs_test_lock(struct file *filp, struct file_lock *fl)
2166 if (filp->f_op->lock)
2167 return filp->f_op->lock(filp, F_GETLK, fl);
2168 posix_test_lock(filp, fl);
2171 EXPORT_SYMBOL_GPL(vfs_test_lock);
2174 * locks_translate_pid - translate a file_lock's fl_pid number into a namespace
2175 * @fl: The file_lock who's fl_pid should be translated
2176 * @ns: The namespace into which the pid should be translated
2178 * Used to tranlate a fl_pid into a namespace virtual pid number
2180 static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns)
2187 if (IS_REMOTELCK(fl))
2190 * If the flock owner process is dead and its pid has been already
2191 * freed, the translation below won't work, but we still want to show
2192 * flock owner pid number in init pidns.
2194 if (ns == &init_pid_ns)
2195 return (pid_t)fl->fl_pid;
2198 pid = find_pid_ns(fl->fl_pid, &init_pid_ns);
2199 vnr = pid_nr_ns(pid, ns);
2204 static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2206 flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
2207 #if BITS_PER_LONG == 32
2209 * Make sure we can represent the posix lock via
2210 * legacy 32bit flock.
2212 if (fl->fl_start > OFFT_OFFSET_MAX)
2214 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2217 flock->l_start = fl->fl_start;
2218 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2219 fl->fl_end - fl->fl_start + 1;
2220 flock->l_whence = 0;
2221 flock->l_type = fl->fl_type;
2225 #if BITS_PER_LONG == 32
2226 static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2228 flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
2229 flock->l_start = fl->fl_start;
2230 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2231 fl->fl_end - fl->fl_start + 1;
2232 flock->l_whence = 0;
2233 flock->l_type = fl->fl_type;
2237 /* Report the first existing lock that would conflict with l.
2238 * This implements the F_GETLK command of fcntl().
2240 int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
2242 struct file_lock *fl;
2245 fl = locks_alloc_lock();
2249 if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
2252 error = flock_to_posix_lock(filp, fl, flock);
2256 if (cmd == F_OFD_GETLK) {
2258 if (flock->l_pid != 0)
2262 fl->fl_flags |= FL_OFDLCK;
2263 fl->fl_owner = filp;
2266 error = vfs_test_lock(filp, fl);
2270 flock->l_type = fl->fl_type;
2271 if (fl->fl_type != F_UNLCK) {
2272 error = posix_lock_to_flock(flock, fl);
2277 locks_free_lock(fl);
2282 * vfs_lock_file - file byte range lock
2283 * @filp: The file to apply the lock to
2284 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2285 * @fl: The lock to be applied
2286 * @conf: Place to return a copy of the conflicting lock, if found.
2288 * A caller that doesn't care about the conflicting lock may pass NULL
2289 * as the final argument.
2291 * If the filesystem defines a private ->lock() method, then @conf will
2292 * be left unchanged; so a caller that cares should initialize it to
2293 * some acceptable default.
2295 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2296 * locks, the ->lock() interface may return asynchronously, before the lock has
2297 * been granted or denied by the underlying filesystem, if (and only if)
2298 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2299 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2300 * the request is for a blocking lock. When ->lock() does return asynchronously,
2301 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2302 * request completes.
2303 * If the request is for non-blocking lock the file system should return
2304 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2305 * with the result. If the request timed out the callback routine will return a
2306 * nonzero return code and the file system should release the lock. The file
2307 * system is also responsible to keep a corresponding posix lock when it
2308 * grants a lock so the VFS can find out which locks are locally held and do
2309 * the correct lock cleanup when required.
2310 * The underlying filesystem must not drop the kernel lock or call
2311 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2314 int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2316 if (filp->f_op->lock)
2317 return filp->f_op->lock(filp, cmd, fl);
2319 return posix_lock_file(filp, fl, conf);
2321 EXPORT_SYMBOL_GPL(vfs_lock_file);
2323 static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2324 struct file_lock *fl)
2328 error = security_file_lock(filp, fl->fl_type);
2333 error = vfs_lock_file(filp, cmd, fl, NULL);
2334 if (error != FILE_LOCK_DEFERRED)
2336 error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker);
2340 locks_delete_block(fl);
2345 /* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
2347 check_fmode_for_setlk(struct file_lock *fl)
2349 switch (fl->fl_type) {
2351 if (!(fl->fl_file->f_mode & FMODE_READ))
2355 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2361 /* Apply the lock described by l to an open file descriptor.
2362 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2364 int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2365 struct flock *flock)
2367 struct file_lock *file_lock = locks_alloc_lock();
2368 struct inode *inode = locks_inode(filp);
2372 if (file_lock == NULL)
2375 /* Don't allow mandatory locks on files that may be memory mapped
2378 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2383 error = flock_to_posix_lock(filp, file_lock, flock);
2387 error = check_fmode_for_setlk(file_lock);
2392 * If the cmd is requesting file-private locks, then set the
2393 * FL_OFDLCK flag and override the owner.
2398 if (flock->l_pid != 0)
2402 file_lock->fl_flags |= FL_OFDLCK;
2403 file_lock->fl_owner = filp;
2407 if (flock->l_pid != 0)
2411 file_lock->fl_flags |= FL_OFDLCK;
2412 file_lock->fl_owner = filp;
2415 file_lock->fl_flags |= FL_SLEEP;
2418 error = do_lock_file_wait(filp, cmd, file_lock);
2421 * Attempt to detect a close/fcntl race and recover by releasing the
2422 * lock that was just acquired. There is no need to do that when we're
2423 * unlocking though, or for OFD locks.
2425 if (!error && file_lock->fl_type != F_UNLCK &&
2426 !(file_lock->fl_flags & FL_OFDLCK)) {
2428 * We need that spin_lock here - it prevents reordering between
2429 * update of i_flctx->flc_posix and check for it done in
2430 * close(). rcu_read_lock() wouldn't do.
2432 spin_lock(¤t->files->file_lock);
2434 spin_unlock(¤t->files->file_lock);
2436 file_lock->fl_type = F_UNLCK;
2437 error = do_lock_file_wait(filp, cmd, file_lock);
2438 WARN_ON_ONCE(error);
2443 trace_fcntl_setlk(inode, file_lock, error);
2444 locks_free_lock(file_lock);
2448 #if BITS_PER_LONG == 32
2449 /* Report the first existing lock that would conflict with l.
2450 * This implements the F_GETLK command of fcntl().
2452 int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
2454 struct file_lock *fl;
2457 fl = locks_alloc_lock();
2462 if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
2465 error = flock64_to_posix_lock(filp, fl, flock);
2469 if (cmd == F_OFD_GETLK) {
2471 if (flock->l_pid != 0)
2475 fl->fl_flags |= FL_OFDLCK;
2476 fl->fl_owner = filp;
2479 error = vfs_test_lock(filp, fl);
2483 flock->l_type = fl->fl_type;
2484 if (fl->fl_type != F_UNLCK)
2485 posix_lock_to_flock64(flock, fl);
2488 locks_free_lock(fl);
2492 /* Apply the lock described by l to an open file descriptor.
2493 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2495 int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2496 struct flock64 *flock)
2498 struct file_lock *file_lock = locks_alloc_lock();
2499 struct inode *inode = locks_inode(filp);
2503 if (file_lock == NULL)
2506 /* Don't allow mandatory locks on files that may be memory mapped
2509 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2514 error = flock64_to_posix_lock(filp, file_lock, flock);
2518 error = check_fmode_for_setlk(file_lock);
2523 * If the cmd is requesting file-private locks, then set the
2524 * FL_OFDLCK flag and override the owner.
2529 if (flock->l_pid != 0)
2533 file_lock->fl_flags |= FL_OFDLCK;
2534 file_lock->fl_owner = filp;
2538 if (flock->l_pid != 0)
2542 file_lock->fl_flags |= FL_OFDLCK;
2543 file_lock->fl_owner = filp;
2546 file_lock->fl_flags |= FL_SLEEP;
2549 error = do_lock_file_wait(filp, cmd, file_lock);
2552 * Attempt to detect a close/fcntl race and recover by releasing the
2553 * lock that was just acquired. There is no need to do that when we're
2554 * unlocking though, or for OFD locks.
2556 if (!error && file_lock->fl_type != F_UNLCK &&
2557 !(file_lock->fl_flags & FL_OFDLCK)) {
2559 * We need that spin_lock here - it prevents reordering between
2560 * update of i_flctx->flc_posix and check for it done in
2561 * close(). rcu_read_lock() wouldn't do.
2563 spin_lock(¤t->files->file_lock);
2565 spin_unlock(¤t->files->file_lock);
2567 file_lock->fl_type = F_UNLCK;
2568 error = do_lock_file_wait(filp, cmd, file_lock);
2569 WARN_ON_ONCE(error);
2574 locks_free_lock(file_lock);
2577 #endif /* BITS_PER_LONG == 32 */
2580 * This function is called when the file is being removed
2581 * from the task's fd array. POSIX locks belonging to this task
2582 * are deleted at this time.
2584 void locks_remove_posix(struct file *filp, fl_owner_t owner)
2587 struct inode *inode = locks_inode(filp);
2588 struct file_lock lock;
2589 struct file_lock_context *ctx;
2592 * If there are no locks held on this file, we don't need to call
2593 * posix_lock_file(). Another process could be setting a lock on this
2594 * file at the same time, but we wouldn't remove that lock anyway.
2596 ctx = smp_load_acquire(&inode->i_flctx);
2597 if (!ctx || list_empty(&ctx->flc_posix))
2600 locks_init_lock(&lock);
2601 lock.fl_type = F_UNLCK;
2602 lock.fl_flags = FL_POSIX | FL_CLOSE;
2604 lock.fl_end = OFFSET_MAX;
2605 lock.fl_owner = owner;
2606 lock.fl_pid = current->tgid;
2607 lock.fl_file = filp;
2609 lock.fl_lmops = NULL;
2611 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
2613 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2614 lock.fl_ops->fl_release_private(&lock);
2615 trace_locks_remove_posix(inode, &lock, error);
2617 EXPORT_SYMBOL(locks_remove_posix);
2619 /* The i_flctx must be valid when calling into here */
2621 locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
2623 struct file_lock fl;
2624 struct inode *inode = locks_inode(filp);
2626 if (list_empty(&flctx->flc_flock))
2629 flock_make_lock(filp, LOCK_UN, &fl);
2630 fl.fl_flags |= FL_CLOSE;
2632 if (filp->f_op->flock)
2633 filp->f_op->flock(filp, F_SETLKW, &fl);
2635 flock_lock_inode(inode, &fl);
2637 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2638 fl.fl_ops->fl_release_private(&fl);
2641 /* The i_flctx must be valid when calling into here */
2643 locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
2645 struct file_lock *fl, *tmp;
2648 if (list_empty(&ctx->flc_lease))
2651 percpu_down_read(&file_rwsem);
2652 spin_lock(&ctx->flc_lock);
2653 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
2654 if (filp == fl->fl_file)
2655 lease_modify(fl, F_UNLCK, &dispose);
2656 spin_unlock(&ctx->flc_lock);
2657 percpu_up_read(&file_rwsem);
2659 locks_dispose_list(&dispose);
2663 * This function is called on the last close of an open file.
2665 void locks_remove_file(struct file *filp)
2667 struct file_lock_context *ctx;
2669 ctx = smp_load_acquire(&locks_inode(filp)->i_flctx);
2673 /* remove any OFD locks */
2674 locks_remove_posix(filp, filp);
2676 /* remove flock locks */
2677 locks_remove_flock(filp, ctx);
2679 /* remove any leases */
2680 locks_remove_lease(filp, ctx);
2682 spin_lock(&ctx->flc_lock);
2683 locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX");
2684 locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK");
2685 locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE");
2686 spin_unlock(&ctx->flc_lock);
2690 * vfs_cancel_lock - file byte range unblock lock
2691 * @filp: The file to apply the unblock to
2692 * @fl: The lock to be unblocked
2694 * Used by lock managers to cancel blocked requests
2696 int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2698 if (filp->f_op->lock)
2699 return filp->f_op->lock(filp, F_CANCELLK, fl);
2702 EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2704 #ifdef CONFIG_PROC_FS
2705 #include <linux/proc_fs.h>
2706 #include <linux/seq_file.h>
2708 struct locks_iterator {
2713 static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2714 loff_t id, char *pfx)
2716 struct inode *inode = NULL;
2717 unsigned int fl_pid;
2718 struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
2720 fl_pid = locks_translate_pid(fl, proc_pidns);
2722 * If lock owner is dead (and pid is freed) or not visible in current
2723 * pidns, zero is shown as a pid value. Check lock info from
2724 * init_pid_ns to get saved lock pid value.
2727 if (fl->fl_file != NULL)
2728 inode = locks_inode(fl->fl_file);
2730 seq_printf(f, "%lld:%s ", id, pfx);
2732 if (fl->fl_flags & FL_ACCESS)
2733 seq_puts(f, "ACCESS");
2734 else if (IS_OFDLCK(fl))
2735 seq_puts(f, "OFDLCK");
2737 seq_puts(f, "POSIX ");
2739 seq_printf(f, " %s ",
2740 (inode == NULL) ? "*NOINODE*" :
2741 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2742 } else if (IS_FLOCK(fl)) {
2743 if (fl->fl_type & LOCK_MAND) {
2744 seq_puts(f, "FLOCK MSNFS ");
2746 seq_puts(f, "FLOCK ADVISORY ");
2748 } else if (IS_LEASE(fl)) {
2749 if (fl->fl_flags & FL_DELEG)
2750 seq_puts(f, "DELEG ");
2752 seq_puts(f, "LEASE ");
2754 if (lease_breaking(fl))
2755 seq_puts(f, "BREAKING ");
2756 else if (fl->fl_file)
2757 seq_puts(f, "ACTIVE ");
2759 seq_puts(f, "BREAKER ");
2761 seq_puts(f, "UNKNOWN UNKNOWN ");
2763 if (fl->fl_type & LOCK_MAND) {
2764 seq_printf(f, "%s ",
2765 (fl->fl_type & LOCK_READ)
2766 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2767 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2769 seq_printf(f, "%s ",
2770 (lease_breaking(fl))
2771 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2772 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
2775 /* userspace relies on this representation of dev_t */
2776 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
2777 MAJOR(inode->i_sb->s_dev),
2778 MINOR(inode->i_sb->s_dev), inode->i_ino);
2780 seq_printf(f, "%d <none>:0 ", fl_pid);
2783 if (fl->fl_end == OFFSET_MAX)
2784 seq_printf(f, "%Ld EOF\n", fl->fl_start);
2786 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2788 seq_puts(f, "0 EOF\n");
2792 static int locks_show(struct seq_file *f, void *v)
2794 struct locks_iterator *iter = f->private;
2795 struct file_lock *fl, *bfl;
2796 struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
2798 fl = hlist_entry(v, struct file_lock, fl_link);
2800 if (locks_translate_pid(fl, proc_pidns) == 0)
2803 lock_get_status(f, fl, iter->li_pos, "");
2805 list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member)
2806 lock_get_status(f, bfl, iter->li_pos, " ->");
2811 static void __show_fd_locks(struct seq_file *f,
2812 struct list_head *head, int *id,
2813 struct file *filp, struct files_struct *files)
2815 struct file_lock *fl;
2817 list_for_each_entry(fl, head, fl_list) {
2819 if (filp != fl->fl_file)
2821 if (fl->fl_owner != files &&
2822 fl->fl_owner != filp)
2826 seq_puts(f, "lock:\t");
2827 lock_get_status(f, fl, *id, "");
2831 void show_fd_locks(struct seq_file *f,
2832 struct file *filp, struct files_struct *files)
2834 struct inode *inode = locks_inode(filp);
2835 struct file_lock_context *ctx;
2838 ctx = smp_load_acquire(&inode->i_flctx);
2842 spin_lock(&ctx->flc_lock);
2843 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2844 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2845 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2846 spin_unlock(&ctx->flc_lock);
2849 static void *locks_start(struct seq_file *f, loff_t *pos)
2850 __acquires(&blocked_lock_lock)
2852 struct locks_iterator *iter = f->private;
2854 iter->li_pos = *pos + 1;
2855 percpu_down_write(&file_rwsem);
2856 spin_lock(&blocked_lock_lock);
2857 return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
2860 static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2862 struct locks_iterator *iter = f->private;
2865 return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
2868 static void locks_stop(struct seq_file *f, void *v)
2869 __releases(&blocked_lock_lock)
2871 spin_unlock(&blocked_lock_lock);
2872 percpu_up_write(&file_rwsem);
2875 static const struct seq_operations locks_seq_operations = {
2876 .start = locks_start,
2882 static int __init proc_locks_init(void)
2884 proc_create_seq_private("locks", 0, NULL, &locks_seq_operations,
2885 sizeof(struct locks_iterator), NULL);
2888 fs_initcall(proc_locks_init);
2891 static int __init filelock_init(void)
2895 flctx_cache = kmem_cache_create("file_lock_ctx",
2896 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2898 filelock_cache = kmem_cache_create("file_lock_cache",
2899 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2901 for_each_possible_cpu(i) {
2902 struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
2904 spin_lock_init(&fll->lock);
2905 INIT_HLIST_HEAD(&fll->hlist);
2910 core_initcall(filelock_init);