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>
130 #include <linux/lglock.h>
132 #define CREATE_TRACE_POINTS
133 #include <trace/events/filelock.h>
135 #include <asm/uaccess.h>
137 #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
138 #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
139 #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
140 #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
142 static inline bool is_remote_lock(struct file *filp)
144 return likely(!(filp->f_path.dentry->d_sb->s_flags & MS_NOREMOTELOCK));
147 static bool lease_breaking(struct file_lock *fl)
149 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
152 static int target_leasetype(struct file_lock *fl)
154 if (fl->fl_flags & FL_UNLOCK_PENDING)
156 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
161 int leases_enable = 1;
162 int lease_break_time = 45;
165 * The global file_lock_list is only used for displaying /proc/locks, so we
166 * keep a list on each CPU, with each list protected by its own spinlock via
167 * the file_lock_lglock. Note that alterations to the list also require that
168 * the relevant flc_lock is held.
170 DEFINE_STATIC_LGLOCK(file_lock_lglock);
171 static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
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 lg_local_lock(&file_lock_lglock);
596 fl->fl_link_cpu = smp_processor_id();
597 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
598 lg_local_unlock(&file_lock_lglock);
601 /* Must be called with the flc_lock held! */
602 static void locks_delete_global_locks(struct file_lock *fl)
605 * Avoid taking lock if already unhashed. This is safe since this check
606 * is done while holding the flc_lock, and new insertions into the list
607 * also require that it be held.
609 if (hlist_unhashed(&fl->fl_link))
611 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
612 hlist_del_init(&fl->fl_link);
613 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
617 posix_owner_key(struct file_lock *fl)
619 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
620 return fl->fl_lmops->lm_owner_key(fl);
621 return (unsigned long)fl->fl_owner;
624 static void locks_insert_global_blocked(struct file_lock *waiter)
626 lockdep_assert_held(&blocked_lock_lock);
628 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
631 static void locks_delete_global_blocked(struct file_lock *waiter)
633 lockdep_assert_held(&blocked_lock_lock);
635 hash_del(&waiter->fl_link);
638 /* Remove waiter from blocker's block list.
639 * When blocker ends up pointing to itself then the list is empty.
641 * Must be called with blocked_lock_lock held.
643 static void __locks_delete_block(struct file_lock *waiter)
645 locks_delete_global_blocked(waiter);
646 list_del_init(&waiter->fl_block);
647 waiter->fl_next = NULL;
650 static void locks_delete_block(struct file_lock *waiter)
652 spin_lock(&blocked_lock_lock);
653 __locks_delete_block(waiter);
654 spin_unlock(&blocked_lock_lock);
657 /* Insert waiter into blocker's block list.
658 * We use a circular list so that processes can be easily woken up in
659 * the order they blocked. The documentation doesn't require this but
660 * it seems like the reasonable thing to do.
662 * Must be called with both the flc_lock and blocked_lock_lock held. The
663 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
664 * that the flc_lock is also held on insertions we can avoid taking the
665 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
667 static void __locks_insert_block(struct file_lock *blocker,
668 struct file_lock *waiter)
670 BUG_ON(!list_empty(&waiter->fl_block));
671 waiter->fl_next = blocker;
672 list_add_tail(&waiter->fl_block, &blocker->fl_block);
673 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
674 locks_insert_global_blocked(waiter);
677 /* Must be called with flc_lock held. */
678 static void locks_insert_block(struct file_lock *blocker,
679 struct file_lock *waiter)
681 spin_lock(&blocked_lock_lock);
682 __locks_insert_block(blocker, waiter);
683 spin_unlock(&blocked_lock_lock);
687 * Wake up processes blocked waiting for blocker.
689 * Must be called with the inode->flc_lock held!
691 static void locks_wake_up_blocks(struct file_lock *blocker)
694 * Avoid taking global lock if list is empty. This is safe since new
695 * blocked requests are only added to the list under the flc_lock, and
696 * the flc_lock is always held here. Note that removal from the fl_block
697 * list does not require the flc_lock, so we must recheck list_empty()
698 * after acquiring the blocked_lock_lock.
700 if (list_empty(&blocker->fl_block))
703 spin_lock(&blocked_lock_lock);
704 while (!list_empty(&blocker->fl_block)) {
705 struct file_lock *waiter;
707 waiter = list_first_entry(&blocker->fl_block,
708 struct file_lock, fl_block);
709 __locks_delete_block(waiter);
710 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
711 waiter->fl_lmops->lm_notify(waiter);
713 wake_up(&waiter->fl_wait);
715 spin_unlock(&blocked_lock_lock);
719 locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
721 fl->fl_nspid = get_pid(task_tgid(current));
722 list_add_tail(&fl->fl_list, before);
723 locks_insert_global_locks(fl);
727 locks_unlink_lock_ctx(struct file_lock *fl)
729 locks_delete_global_locks(fl);
730 list_del_init(&fl->fl_list);
732 put_pid(fl->fl_nspid);
735 locks_wake_up_blocks(fl);
739 locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
741 locks_unlink_lock_ctx(fl);
743 list_add(&fl->fl_list, dispose);
748 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
749 * checks for shared/exclusive status of overlapping locks.
751 static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
753 if (sys_fl->fl_type == F_WRLCK)
755 if (caller_fl->fl_type == F_WRLCK)
760 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
761 * checking before calling the locks_conflict().
763 static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
765 /* POSIX locks owned by the same process do not conflict with
768 if (posix_same_owner(caller_fl, sys_fl))
771 /* Check whether they overlap */
772 if (!locks_overlap(caller_fl, sys_fl))
775 return (locks_conflict(caller_fl, sys_fl));
778 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
779 * checking before calling the locks_conflict().
781 static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
783 /* FLOCK locks referring to the same filp do not conflict with
786 if (caller_fl->fl_file == sys_fl->fl_file)
788 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
791 return (locks_conflict(caller_fl, sys_fl));
795 posix_test_lock(struct file *filp, struct file_lock *fl)
797 struct file_lock *cfl;
798 struct file_lock_context *ctx;
799 struct inode *inode = locks_inode(filp);
801 ctx = smp_load_acquire(&inode->i_flctx);
802 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
803 fl->fl_type = F_UNLCK;
807 spin_lock(&ctx->flc_lock);
808 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
809 if (posix_locks_conflict(fl, cfl)) {
810 locks_copy_conflock(fl, cfl);
812 fl->fl_pid = pid_vnr(cfl->fl_nspid);
816 fl->fl_type = F_UNLCK;
818 spin_unlock(&ctx->flc_lock);
821 EXPORT_SYMBOL(posix_test_lock);
824 * Deadlock detection:
826 * We attempt to detect deadlocks that are due purely to posix file
829 * We assume that a task can be waiting for at most one lock at a time.
830 * So for any acquired lock, the process holding that lock may be
831 * waiting on at most one other lock. That lock in turns may be held by
832 * someone waiting for at most one other lock. Given a requested lock
833 * caller_fl which is about to wait for a conflicting lock block_fl, we
834 * follow this chain of waiters to ensure we are not about to create a
837 * Since we do this before we ever put a process to sleep on a lock, we
838 * are ensured that there is never a cycle; that is what guarantees that
839 * the while() loop in posix_locks_deadlock() eventually completes.
841 * Note: the above assumption may not be true when handling lock
842 * requests from a broken NFS client. It may also fail in the presence
843 * of tasks (such as posix threads) sharing the same open file table.
844 * To handle those cases, we just bail out after a few iterations.
846 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
847 * Because the owner is not even nominally tied to a thread of
848 * execution, the deadlock detection below can't reasonably work well. Just
851 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
852 * locks that just checks for the case where two tasks are attempting to
853 * upgrade from read to write locks on the same inode.
856 #define MAX_DEADLK_ITERATIONS 10
858 /* Find a lock that the owner of the given block_fl is blocking on. */
859 static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
861 struct file_lock *fl;
863 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
864 if (posix_same_owner(fl, block_fl))
870 /* Must be called with the blocked_lock_lock held! */
871 static int posix_locks_deadlock(struct file_lock *caller_fl,
872 struct file_lock *block_fl)
876 lockdep_assert_held(&blocked_lock_lock);
879 * This deadlock detector can't reasonably detect deadlocks with
880 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
882 if (IS_OFDLCK(caller_fl))
885 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
886 if (i++ > MAX_DEADLK_ITERATIONS)
888 if (posix_same_owner(caller_fl, block_fl))
894 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
895 * after any leases, but before any posix locks.
897 * Note that if called with an FL_EXISTS argument, the caller may determine
898 * whether or not a lock was successfully freed by testing the return
901 static int flock_lock_inode(struct inode *inode, struct file_lock *request)
903 struct file_lock *new_fl = NULL;
904 struct file_lock *fl;
905 struct file_lock_context *ctx;
910 ctx = locks_get_lock_context(inode, request->fl_type);
912 if (request->fl_type != F_UNLCK)
914 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
917 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
918 new_fl = locks_alloc_lock();
923 spin_lock(&ctx->flc_lock);
924 if (request->fl_flags & FL_ACCESS)
927 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
928 if (request->fl_file != fl->fl_file)
930 if (request->fl_type == fl->fl_type)
933 locks_delete_lock_ctx(fl, &dispose);
937 if (request->fl_type == F_UNLCK) {
938 if ((request->fl_flags & FL_EXISTS) && !found)
944 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
945 if (!flock_locks_conflict(request, fl))
948 if (!(request->fl_flags & FL_SLEEP))
950 error = FILE_LOCK_DEFERRED;
951 locks_insert_block(fl, request);
954 if (request->fl_flags & FL_ACCESS)
956 locks_copy_lock(new_fl, request);
957 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
962 spin_unlock(&ctx->flc_lock);
964 locks_free_lock(new_fl);
965 locks_dispose_list(&dispose);
969 static int posix_lock_inode(struct inode *inode, struct file_lock *request,
970 struct file_lock *conflock)
972 struct file_lock *fl, *tmp;
973 struct file_lock *new_fl = NULL;
974 struct file_lock *new_fl2 = NULL;
975 struct file_lock *left = NULL;
976 struct file_lock *right = NULL;
977 struct file_lock_context *ctx;
982 ctx = locks_get_lock_context(inode, request->fl_type);
984 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
987 * We may need two file_lock structures for this operation,
988 * so we get them in advance to avoid races.
990 * In some cases we can be sure, that no new locks will be needed
992 if (!(request->fl_flags & FL_ACCESS) &&
993 (request->fl_type != F_UNLCK ||
994 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
995 new_fl = locks_alloc_lock();
996 new_fl2 = locks_alloc_lock();
999 spin_lock(&ctx->flc_lock);
1001 * New lock request. Walk all POSIX locks and look for conflicts. If
1002 * there are any, either return error or put the request on the
1003 * blocker's list of waiters and the global blocked_hash.
1005 if (request->fl_type != F_UNLCK) {
1006 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1007 if (!posix_locks_conflict(request, fl))
1010 locks_copy_conflock(conflock, fl);
1012 if (!(request->fl_flags & FL_SLEEP))
1015 * Deadlock detection and insertion into the blocked
1016 * locks list must be done while holding the same lock!
1019 spin_lock(&blocked_lock_lock);
1020 if (likely(!posix_locks_deadlock(request, fl))) {
1021 error = FILE_LOCK_DEFERRED;
1022 __locks_insert_block(fl, request);
1024 spin_unlock(&blocked_lock_lock);
1029 /* If we're just looking for a conflict, we're done. */
1031 if (request->fl_flags & FL_ACCESS)
1034 /* Find the first old lock with the same owner as the new lock */
1035 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1036 if (posix_same_owner(request, fl))
1040 /* Process locks with this owner. */
1041 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1042 if (!posix_same_owner(request, fl))
1045 /* Detect adjacent or overlapping regions (if same lock type) */
1046 if (request->fl_type == fl->fl_type) {
1047 /* In all comparisons of start vs end, use
1048 * "start - 1" rather than "end + 1". If end
1049 * is OFFSET_MAX, end + 1 will become negative.
1051 if (fl->fl_end < request->fl_start - 1)
1053 /* If the next lock in the list has entirely bigger
1054 * addresses than the new one, insert the lock here.
1056 if (fl->fl_start - 1 > request->fl_end)
1059 /* If we come here, the new and old lock are of the
1060 * same type and adjacent or overlapping. Make one
1061 * lock yielding from the lower start address of both
1062 * locks to the higher end address.
1064 if (fl->fl_start > request->fl_start)
1065 fl->fl_start = request->fl_start;
1067 request->fl_start = fl->fl_start;
1068 if (fl->fl_end < request->fl_end)
1069 fl->fl_end = request->fl_end;
1071 request->fl_end = fl->fl_end;
1073 locks_delete_lock_ctx(fl, &dispose);
1079 /* Processing for different lock types is a bit
1082 if (fl->fl_end < request->fl_start)
1084 if (fl->fl_start > request->fl_end)
1086 if (request->fl_type == F_UNLCK)
1088 if (fl->fl_start < request->fl_start)
1090 /* If the next lock in the list has a higher end
1091 * address than the new one, insert the new one here.
1093 if (fl->fl_end > request->fl_end) {
1097 if (fl->fl_start >= request->fl_start) {
1098 /* The new lock completely replaces an old
1099 * one (This may happen several times).
1102 locks_delete_lock_ctx(fl, &dispose);
1106 * Replace the old lock with new_fl, and
1107 * remove the old one. It's safe to do the
1108 * insert here since we know that we won't be
1109 * using new_fl later, and that the lock is
1110 * just replacing an existing lock.
1115 locks_copy_lock(new_fl, request);
1118 locks_insert_lock_ctx(request, &fl->fl_list);
1119 locks_delete_lock_ctx(fl, &dispose);
1126 * The above code only modifies existing locks in case of merging or
1127 * replacing. If new lock(s) need to be inserted all modifications are
1128 * done below this, so it's safe yet to bail out.
1130 error = -ENOLCK; /* "no luck" */
1131 if (right && left == right && !new_fl2)
1136 if (request->fl_type == F_UNLCK) {
1137 if (request->fl_flags & FL_EXISTS)
1146 locks_copy_lock(new_fl, request);
1147 locks_insert_lock_ctx(new_fl, &fl->fl_list);
1152 if (left == right) {
1153 /* The new lock breaks the old one in two pieces,
1154 * so we have to use the second new lock.
1158 locks_copy_lock(left, right);
1159 locks_insert_lock_ctx(left, &fl->fl_list);
1161 right->fl_start = request->fl_end + 1;
1162 locks_wake_up_blocks(right);
1165 left->fl_end = request->fl_start - 1;
1166 locks_wake_up_blocks(left);
1169 spin_unlock(&ctx->flc_lock);
1171 * Free any unused locks.
1174 locks_free_lock(new_fl);
1176 locks_free_lock(new_fl2);
1177 locks_dispose_list(&dispose);
1178 trace_posix_lock_inode(inode, request, error);
1184 * posix_lock_file - Apply a POSIX-style lock to a file
1185 * @filp: The file to apply the lock to
1186 * @fl: The lock to be applied
1187 * @conflock: Place to return a copy of the conflicting lock, if found.
1189 * Add a POSIX style lock to a file.
1190 * We merge adjacent & overlapping locks whenever possible.
1191 * POSIX locks are sorted by owner task, then by starting address
1193 * Note that if called with an FL_EXISTS argument, the caller may determine
1194 * whether or not a lock was successfully freed by testing the return
1195 * value for -ENOENT.
1197 int posix_lock_file(struct file *filp, struct file_lock *fl,
1198 struct file_lock *conflock)
1200 return posix_lock_inode(locks_inode(filp), fl, conflock);
1202 EXPORT_SYMBOL(posix_lock_file);
1205 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1206 * @inode: inode of file to which lock request should be applied
1207 * @fl: The lock to be applied
1209 * Apply a POSIX style lock request to an inode.
1211 static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1216 error = posix_lock_inode(inode, fl, NULL);
1217 if (error != FILE_LOCK_DEFERRED)
1219 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1223 locks_delete_block(fl);
1229 #ifdef CONFIG_MANDATORY_FILE_LOCKING
1231 * locks_mandatory_locked - Check for an active lock
1232 * @file: the file to check
1234 * Searches the inode's list of locks to find any POSIX locks which conflict.
1235 * This function is called from locks_verify_locked() only.
1237 int locks_mandatory_locked(struct file *file)
1240 struct inode *inode = locks_inode(file);
1241 struct file_lock_context *ctx;
1242 struct file_lock *fl;
1244 ctx = smp_load_acquire(&inode->i_flctx);
1245 if (!ctx || list_empty_careful(&ctx->flc_posix))
1249 * Search the lock list for this inode for any POSIX locks.
1251 spin_lock(&ctx->flc_lock);
1253 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1254 if (fl->fl_owner != current->files &&
1255 fl->fl_owner != file) {
1260 spin_unlock(&ctx->flc_lock);
1265 * locks_mandatory_area - Check for a conflicting lock
1266 * @inode: the file to check
1267 * @filp: how the file was opened (if it was)
1268 * @start: first byte in the file to check
1269 * @end: lastbyte in the file to check
1270 * @type: %F_WRLCK for a write lock, else %F_RDLCK
1272 * Searches the inode's list of locks to find any POSIX locks which conflict.
1274 int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1275 loff_t end, unsigned char type)
1277 struct file_lock fl;
1281 locks_init_lock(&fl);
1282 fl.fl_pid = current->tgid;
1284 fl.fl_flags = FL_POSIX | FL_ACCESS;
1285 if (filp && !(filp->f_flags & O_NONBLOCK))
1288 fl.fl_start = start;
1294 fl.fl_flags &= ~FL_SLEEP;
1295 error = posix_lock_inode(inode, &fl, NULL);
1301 fl.fl_flags |= FL_SLEEP;
1302 fl.fl_owner = current->files;
1303 error = posix_lock_inode(inode, &fl, NULL);
1304 if (error != FILE_LOCK_DEFERRED)
1306 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1309 * If we've been sleeping someone might have
1310 * changed the permissions behind our back.
1312 if (__mandatory_lock(inode))
1316 locks_delete_block(&fl);
1323 EXPORT_SYMBOL(locks_mandatory_area);
1324 #endif /* CONFIG_MANDATORY_FILE_LOCKING */
1326 static void lease_clear_pending(struct file_lock *fl, int arg)
1330 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1333 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1337 /* We already had a lease on this file; just change its type */
1338 int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
1340 int error = assign_type(fl, arg);
1344 lease_clear_pending(fl, arg);
1345 locks_wake_up_blocks(fl);
1346 if (arg == F_UNLCK) {
1347 struct file *filp = fl->fl_file;
1350 filp->f_owner.signum = 0;
1351 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1352 if (fl->fl_fasync != NULL) {
1353 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1354 fl->fl_fasync = NULL;
1356 locks_delete_lock_ctx(fl, dispose);
1360 EXPORT_SYMBOL(lease_modify);
1362 static bool past_time(unsigned long then)
1365 /* 0 is a special value meaning "this never expires": */
1367 return time_after(jiffies, then);
1370 static void time_out_leases(struct inode *inode, struct list_head *dispose)
1372 struct file_lock_context *ctx = inode->i_flctx;
1373 struct file_lock *fl, *tmp;
1375 lockdep_assert_held(&ctx->flc_lock);
1377 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1378 trace_time_out_leases(inode, fl);
1379 if (past_time(fl->fl_downgrade_time))
1380 lease_modify(fl, F_RDLCK, dispose);
1381 if (past_time(fl->fl_break_time))
1382 lease_modify(fl, F_UNLCK, dispose);
1386 static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1388 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1390 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1392 return locks_conflict(breaker, lease);
1396 any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1398 struct file_lock_context *ctx = inode->i_flctx;
1399 struct file_lock *fl;
1401 lockdep_assert_held(&ctx->flc_lock);
1403 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1404 if (leases_conflict(fl, breaker))
1411 * __break_lease - revoke all outstanding leases on file
1412 * @inode: the inode of the file to return
1413 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1415 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1418 * break_lease (inlined for speed) has checked there already is at least
1419 * some kind of lock (maybe a lease) on this file. Leases are broken on
1420 * a call to open() or truncate(). This function can sleep unless you
1421 * specified %O_NONBLOCK to your open().
1423 int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
1426 struct file_lock_context *ctx;
1427 struct file_lock *new_fl, *fl, *tmp;
1428 unsigned long break_time;
1429 int want_write = (mode & O_ACCMODE) != O_RDONLY;
1432 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
1434 return PTR_ERR(new_fl);
1435 new_fl->fl_flags = type;
1437 /* typically we will check that ctx is non-NULL before calling */
1438 ctx = smp_load_acquire(&inode->i_flctx);
1444 spin_lock(&ctx->flc_lock);
1446 time_out_leases(inode, &dispose);
1448 if (!any_leases_conflict(inode, new_fl))
1452 if (lease_break_time > 0) {
1453 break_time = jiffies + lease_break_time * HZ;
1454 if (break_time == 0)
1455 break_time++; /* so that 0 means no break time */
1458 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
1459 if (!leases_conflict(fl, new_fl))
1462 if (fl->fl_flags & FL_UNLOCK_PENDING)
1464 fl->fl_flags |= FL_UNLOCK_PENDING;
1465 fl->fl_break_time = break_time;
1467 if (lease_breaking(fl))
1469 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1470 fl->fl_downgrade_time = break_time;
1472 if (fl->fl_lmops->lm_break(fl))
1473 locks_delete_lock_ctx(fl, &dispose);
1476 if (list_empty(&ctx->flc_lease))
1479 if (mode & O_NONBLOCK) {
1480 trace_break_lease_noblock(inode, new_fl);
1481 error = -EWOULDBLOCK;
1486 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1487 break_time = fl->fl_break_time;
1488 if (break_time != 0)
1489 break_time -= jiffies;
1490 if (break_time == 0)
1492 locks_insert_block(fl, new_fl);
1493 trace_break_lease_block(inode, new_fl);
1494 spin_unlock(&ctx->flc_lock);
1495 locks_dispose_list(&dispose);
1496 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1497 !new_fl->fl_next, break_time);
1498 spin_lock(&ctx->flc_lock);
1499 trace_break_lease_unblock(inode, new_fl);
1500 locks_delete_block(new_fl);
1503 * Wait for the next conflicting lease that has not been
1507 time_out_leases(inode, &dispose);
1508 if (any_leases_conflict(inode, new_fl))
1513 spin_unlock(&ctx->flc_lock);
1514 locks_dispose_list(&dispose);
1515 locks_free_lock(new_fl);
1519 EXPORT_SYMBOL(__break_lease);
1522 * lease_get_mtime - get the last modified time of an inode
1524 * @time: pointer to a timespec which will contain the last modified time
1526 * This is to force NFS clients to flush their caches for files with
1527 * exclusive leases. The justification is that if someone has an
1528 * exclusive lease, then they could be modifying it.
1530 void lease_get_mtime(struct inode *inode, struct timespec *time)
1532 bool has_lease = false;
1533 struct file_lock_context *ctx;
1534 struct file_lock *fl;
1536 ctx = smp_load_acquire(&inode->i_flctx);
1537 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1538 spin_lock(&ctx->flc_lock);
1539 fl = list_first_entry_or_null(&ctx->flc_lease,
1540 struct file_lock, fl_list);
1541 if (fl && (fl->fl_type == F_WRLCK))
1543 spin_unlock(&ctx->flc_lock);
1547 *time = current_fs_time(inode->i_sb);
1549 *time = inode->i_mtime;
1552 EXPORT_SYMBOL(lease_get_mtime);
1555 * fcntl_getlease - Enquire what lease is currently active
1558 * The value returned by this function will be one of
1559 * (if no lease break is pending):
1561 * %F_RDLCK to indicate a shared lease is held.
1563 * %F_WRLCK to indicate an exclusive lease is held.
1565 * %F_UNLCK to indicate no lease is held.
1567 * (if a lease break is pending):
1569 * %F_RDLCK to indicate an exclusive lease needs to be
1570 * changed to a shared lease (or removed).
1572 * %F_UNLCK to indicate the lease needs to be removed.
1574 * XXX: sfr & willy disagree over whether F_INPROGRESS
1575 * should be returned to userspace.
1577 int fcntl_getlease(struct file *filp)
1579 struct file_lock *fl;
1580 struct inode *inode = locks_inode(filp);
1581 struct file_lock_context *ctx;
1585 ctx = smp_load_acquire(&inode->i_flctx);
1586 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
1587 spin_lock(&ctx->flc_lock);
1588 time_out_leases(inode, &dispose);
1589 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1590 if (fl->fl_file != filp)
1592 type = target_leasetype(fl);
1595 spin_unlock(&ctx->flc_lock);
1596 locks_dispose_list(&dispose);
1602 * check_conflicting_open - see if the given dentry points to a file that has
1603 * an existing open that would conflict with the
1605 * @dentry: dentry to check
1606 * @arg: type of lease that we're trying to acquire
1607 * @flags: current lock flags
1609 * Check to see if there's an existing open fd on this file that would
1610 * conflict with the lease we're trying to set.
1613 check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
1616 struct inode *inode = dentry->d_inode;
1618 if (flags & FL_LAYOUT)
1621 if ((arg == F_RDLCK) &&
1622 (atomic_read(&d_real_inode(dentry)->i_writecount) > 0))
1625 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1626 (atomic_read(&inode->i_count) > 1)))
1633 generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
1635 struct file_lock *fl, *my_fl = NULL, *lease;
1636 struct dentry *dentry = filp->f_path.dentry;
1637 struct inode *inode = dentry->d_inode;
1638 struct file_lock_context *ctx;
1639 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
1644 trace_generic_add_lease(inode, lease);
1646 /* Note that arg is never F_UNLCK here */
1647 ctx = locks_get_lock_context(inode, arg);
1652 * In the delegation case we need mutual exclusion with
1653 * a number of operations that take the i_mutex. We trylock
1654 * because delegations are an optional optimization, and if
1655 * there's some chance of a conflict--we'd rather not
1656 * bother, maybe that's a sign this just isn't a good file to
1657 * hand out a delegation on.
1659 if (is_deleg && !inode_trylock(inode))
1662 if (is_deleg && arg == F_WRLCK) {
1663 /* Write delegations are not currently supported: */
1664 inode_unlock(inode);
1669 spin_lock(&ctx->flc_lock);
1670 time_out_leases(inode, &dispose);
1671 error = check_conflicting_open(dentry, arg, lease->fl_flags);
1676 * At this point, we know that if there is an exclusive
1677 * lease on this file, then we hold it on this filp
1678 * (otherwise our open of this file would have blocked).
1679 * And if we are trying to acquire an exclusive lease,
1680 * then the file is not open by anyone (including us)
1681 * except for this filp.
1684 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1685 if (fl->fl_file == filp &&
1686 fl->fl_owner == lease->fl_owner) {
1692 * No exclusive leases if someone else has a lease on
1698 * Modifying our existing lease is OK, but no getting a
1699 * new lease if someone else is opening for write:
1701 if (fl->fl_flags & FL_UNLOCK_PENDING)
1705 if (my_fl != NULL) {
1707 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
1717 locks_insert_lock_ctx(lease, &ctx->flc_lease);
1719 * The check in break_lease() is lockless. It's possible for another
1720 * open to race in after we did the earlier check for a conflicting
1721 * open but before the lease was inserted. Check again for a
1722 * conflicting open and cancel the lease if there is one.
1724 * We also add a barrier here to ensure that the insertion of the lock
1725 * precedes these checks.
1728 error = check_conflicting_open(dentry, arg, lease->fl_flags);
1730 locks_unlink_lock_ctx(lease);
1735 if (lease->fl_lmops->lm_setup)
1736 lease->fl_lmops->lm_setup(lease, priv);
1738 spin_unlock(&ctx->flc_lock);
1739 locks_dispose_list(&dispose);
1741 inode_unlock(inode);
1742 if (!error && !my_fl)
1747 static int generic_delete_lease(struct file *filp, void *owner)
1749 int error = -EAGAIN;
1750 struct file_lock *fl, *victim = NULL;
1751 struct inode *inode = locks_inode(filp);
1752 struct file_lock_context *ctx;
1755 ctx = smp_load_acquire(&inode->i_flctx);
1757 trace_generic_delete_lease(inode, NULL);
1761 spin_lock(&ctx->flc_lock);
1762 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1763 if (fl->fl_file == filp &&
1764 fl->fl_owner == owner) {
1769 trace_generic_delete_lease(inode, victim);
1771 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
1772 spin_unlock(&ctx->flc_lock);
1773 locks_dispose_list(&dispose);
1778 * generic_setlease - sets a lease on an open file
1779 * @filp: file pointer
1780 * @arg: type of lease to obtain
1781 * @flp: input - file_lock to use, output - file_lock inserted
1782 * @priv: private data for lm_setup (may be NULL if lm_setup
1783 * doesn't require it)
1785 * The (input) flp->fl_lmops->lm_break function is required
1788 int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1791 struct inode *inode = locks_inode(filp);
1794 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
1796 if (!S_ISREG(inode->i_mode))
1798 error = security_file_lock(filp, arg);
1804 return generic_delete_lease(filp, *priv);
1807 if (!(*flp)->fl_lmops->lm_break) {
1812 return generic_add_lease(filp, arg, flp, priv);
1817 EXPORT_SYMBOL(generic_setlease);
1820 * vfs_setlease - sets a lease on an open file
1821 * @filp: file pointer
1822 * @arg: type of lease to obtain
1823 * @lease: file_lock to use when adding a lease
1824 * @priv: private info for lm_setup when adding a lease (may be
1825 * NULL if lm_setup doesn't require it)
1827 * Call this to establish a lease on the file. The "lease" argument is not
1828 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1829 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1830 * if not, this function will return -ENOLCK (and generate a scary-looking
1833 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1834 * may be NULL if the lm_setup operation doesn't require it.
1837 vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
1839 if (filp->f_op->setlease && is_remote_lock(filp))
1840 return filp->f_op->setlease(filp, arg, lease, priv);
1842 return generic_setlease(filp, arg, lease, priv);
1844 EXPORT_SYMBOL_GPL(vfs_setlease);
1846 static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
1848 struct file_lock *fl;
1849 struct fasync_struct *new;
1852 fl = lease_alloc(filp, arg);
1856 new = fasync_alloc();
1858 locks_free_lock(fl);
1863 error = vfs_setlease(filp, arg, &fl, (void **)&new);
1865 locks_free_lock(fl);
1872 * fcntl_setlease - sets a lease on an open file
1873 * @fd: open file descriptor
1874 * @filp: file pointer
1875 * @arg: type of lease to obtain
1877 * Call this fcntl to establish a lease on the file.
1878 * Note that you also need to call %F_SETSIG to
1879 * receive a signal when the lease is broken.
1881 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1884 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
1885 return do_fcntl_add_lease(fd, filp, arg);
1889 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1890 * @inode: inode of the file to apply to
1891 * @fl: The lock to be applied
1893 * Apply a FLOCK style lock request to an inode.
1895 static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1900 error = flock_lock_inode(inode, fl);
1901 if (error != FILE_LOCK_DEFERRED)
1903 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1907 locks_delete_block(fl);
1914 * locks_lock_inode_wait - Apply a lock to an inode
1915 * @inode: inode of the file to apply to
1916 * @fl: The lock to be applied
1918 * Apply a POSIX or FLOCK style lock request to an inode.
1920 int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1923 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1925 res = posix_lock_inode_wait(inode, fl);
1928 res = flock_lock_inode_wait(inode, fl);
1935 EXPORT_SYMBOL(locks_lock_inode_wait);
1938 * sys_flock: - flock() system call.
1939 * @fd: the file descriptor to lock.
1940 * @cmd: the type of lock to apply.
1942 * Apply a %FL_FLOCK style lock to an open file descriptor.
1943 * The @cmd can be one of
1945 * %LOCK_SH -- a shared lock.
1947 * %LOCK_EX -- an exclusive lock.
1949 * %LOCK_UN -- remove an existing lock.
1951 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1953 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1954 * processes read and write access respectively.
1956 SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
1958 struct fd f = fdget(fd);
1959 struct file_lock *lock;
1960 int can_sleep, unlock;
1967 can_sleep = !(cmd & LOCK_NB);
1969 unlock = (cmd == LOCK_UN);
1971 if (!unlock && !(cmd & LOCK_MAND) &&
1972 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
1975 lock = flock_make_lock(f.file, cmd);
1977 error = PTR_ERR(lock);
1982 lock->fl_flags |= FL_SLEEP;
1984 error = security_file_lock(f.file, lock->fl_type);
1988 if (f.file->f_op->flock && is_remote_lock(f.file))
1989 error = f.file->f_op->flock(f.file,
1990 (can_sleep) ? F_SETLKW : F_SETLK,
1993 error = locks_lock_file_wait(f.file, lock);
1996 locks_free_lock(lock);
2005 * vfs_test_lock - test file byte range lock
2006 * @filp: The file to test lock for
2007 * @fl: The lock to test; also used to hold result
2009 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2010 * setting conf->fl_type to something other than F_UNLCK.
2012 int vfs_test_lock(struct file *filp, struct file_lock *fl)
2014 if (filp->f_op->lock && is_remote_lock(filp))
2015 return filp->f_op->lock(filp, F_GETLK, fl);
2016 posix_test_lock(filp, fl);
2019 EXPORT_SYMBOL_GPL(vfs_test_lock);
2021 static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2023 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
2024 #if BITS_PER_LONG == 32
2026 * Make sure we can represent the posix lock via
2027 * legacy 32bit flock.
2029 if (fl->fl_start > OFFT_OFFSET_MAX)
2031 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2034 flock->l_start = fl->fl_start;
2035 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2036 fl->fl_end - fl->fl_start + 1;
2037 flock->l_whence = 0;
2038 flock->l_type = fl->fl_type;
2042 #if BITS_PER_LONG == 32
2043 static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2045 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
2046 flock->l_start = fl->fl_start;
2047 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2048 fl->fl_end - fl->fl_start + 1;
2049 flock->l_whence = 0;
2050 flock->l_type = fl->fl_type;
2054 /* Report the first existing lock that would conflict with l.
2055 * This implements the F_GETLK command of fcntl().
2057 int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
2059 struct file_lock file_lock;
2064 if (copy_from_user(&flock, l, sizeof(flock)))
2067 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2070 error = flock_to_posix_lock(filp, &file_lock, &flock);
2074 if (cmd == F_OFD_GETLK) {
2076 if (flock.l_pid != 0)
2080 file_lock.fl_flags |= FL_OFDLCK;
2081 file_lock.fl_owner = filp;
2084 error = vfs_test_lock(filp, &file_lock);
2088 flock.l_type = file_lock.fl_type;
2089 if (file_lock.fl_type != F_UNLCK) {
2090 error = posix_lock_to_flock(&flock, &file_lock);
2095 if (!copy_to_user(l, &flock, sizeof(flock)))
2098 locks_release_private(&file_lock);
2104 * vfs_lock_file - file byte range lock
2105 * @filp: The file to apply the lock to
2106 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2107 * @fl: The lock to be applied
2108 * @conf: Place to return a copy of the conflicting lock, if found.
2110 * A caller that doesn't care about the conflicting lock may pass NULL
2111 * as the final argument.
2113 * If the filesystem defines a private ->lock() method, then @conf will
2114 * be left unchanged; so a caller that cares should initialize it to
2115 * some acceptable default.
2117 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2118 * locks, the ->lock() interface may return asynchronously, before the lock has
2119 * been granted or denied by the underlying filesystem, if (and only if)
2120 * lm_grant is set. Callers expecting ->lock() to return asynchronously
2121 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2122 * the request is for a blocking lock. When ->lock() does return asynchronously,
2123 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
2124 * request completes.
2125 * If the request is for non-blocking lock the file system should return
2126 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2127 * with the result. If the request timed out the callback routine will return a
2128 * nonzero return code and the file system should release the lock. The file
2129 * system is also responsible to keep a corresponding posix lock when it
2130 * grants a lock so the VFS can find out which locks are locally held and do
2131 * the correct lock cleanup when required.
2132 * The underlying filesystem must not drop the kernel lock or call
2133 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
2136 int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
2138 if (filp->f_op->lock && is_remote_lock(filp))
2139 return filp->f_op->lock(filp, cmd, fl);
2141 return posix_lock_file(filp, fl, conf);
2143 EXPORT_SYMBOL_GPL(vfs_lock_file);
2145 static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2146 struct file_lock *fl)
2150 error = security_file_lock(filp, fl->fl_type);
2155 error = vfs_lock_file(filp, cmd, fl, NULL);
2156 if (error != FILE_LOCK_DEFERRED)
2158 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2162 locks_delete_block(fl);
2169 /* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
2171 check_fmode_for_setlk(struct file_lock *fl)
2173 switch (fl->fl_type) {
2175 if (!(fl->fl_file->f_mode & FMODE_READ))
2179 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2185 /* Apply the lock described by l to an open file descriptor.
2186 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2188 int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2189 struct flock __user *l)
2191 struct file_lock *file_lock = locks_alloc_lock();
2193 struct inode *inode;
2197 if (file_lock == NULL)
2200 inode = locks_inode(filp);
2203 * This might block, so we do it before checking the inode.
2206 if (copy_from_user(&flock, l, sizeof(flock)))
2209 /* Don't allow mandatory locks on files that may be memory mapped
2212 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2217 error = flock_to_posix_lock(filp, file_lock, &flock);
2221 error = check_fmode_for_setlk(file_lock);
2226 * If the cmd is requesting file-private locks, then set the
2227 * FL_OFDLCK flag and override the owner.
2232 if (flock.l_pid != 0)
2236 file_lock->fl_flags |= FL_OFDLCK;
2237 file_lock->fl_owner = filp;
2241 if (flock.l_pid != 0)
2245 file_lock->fl_flags |= FL_OFDLCK;
2246 file_lock->fl_owner = filp;
2249 file_lock->fl_flags |= FL_SLEEP;
2252 error = do_lock_file_wait(filp, cmd, file_lock);
2255 * Attempt to detect a close/fcntl race and recover by releasing the
2256 * lock that was just acquired. There is no need to do that when we're
2257 * unlocking though, or for OFD locks.
2259 if (!error && file_lock->fl_type != F_UNLCK &&
2260 !(file_lock->fl_flags & FL_OFDLCK)) {
2262 * We need that spin_lock here - it prevents reordering between
2263 * update of i_flctx->flc_posix and check for it done in
2264 * close(). rcu_read_lock() wouldn't do.
2266 spin_lock(¤t->files->file_lock);
2268 spin_unlock(¤t->files->file_lock);
2270 file_lock->fl_type = F_UNLCK;
2271 error = do_lock_file_wait(filp, cmd, file_lock);
2272 WARN_ON_ONCE(error);
2277 trace_fcntl_setlk(inode, file_lock, error);
2278 locks_free_lock(file_lock);
2282 #if BITS_PER_LONG == 32
2283 /* Report the first existing lock that would conflict with l.
2284 * This implements the F_GETLK command of fcntl().
2286 int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
2288 struct file_lock file_lock;
2289 struct flock64 flock;
2293 if (copy_from_user(&flock, l, sizeof(flock)))
2296 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2299 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2303 if (cmd == F_OFD_GETLK) {
2305 if (flock.l_pid != 0)
2309 file_lock.fl_flags |= FL_OFDLCK;
2310 file_lock.fl_owner = filp;
2313 error = vfs_test_lock(filp, &file_lock);
2317 flock.l_type = file_lock.fl_type;
2318 if (file_lock.fl_type != F_UNLCK)
2319 posix_lock_to_flock64(&flock, &file_lock);
2322 if (!copy_to_user(l, &flock, sizeof(flock)))
2325 locks_release_private(&file_lock);
2330 /* Apply the lock described by l to an open file descriptor.
2331 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2333 int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2334 struct flock64 __user *l)
2336 struct file_lock *file_lock = locks_alloc_lock();
2337 struct flock64 flock;
2338 struct inode *inode;
2342 if (file_lock == NULL)
2346 * This might block, so we do it before checking the inode.
2349 if (copy_from_user(&flock, l, sizeof(flock)))
2352 inode = locks_inode(filp);
2354 /* Don't allow mandatory locks on files that may be memory mapped
2357 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
2362 error = flock64_to_posix_lock(filp, file_lock, &flock);
2366 error = check_fmode_for_setlk(file_lock);
2371 * If the cmd is requesting file-private locks, then set the
2372 * FL_OFDLCK flag and override the owner.
2377 if (flock.l_pid != 0)
2381 file_lock->fl_flags |= FL_OFDLCK;
2382 file_lock->fl_owner = filp;
2386 if (flock.l_pid != 0)
2390 file_lock->fl_flags |= FL_OFDLCK;
2391 file_lock->fl_owner = filp;
2394 file_lock->fl_flags |= FL_SLEEP;
2397 error = do_lock_file_wait(filp, cmd, file_lock);
2400 * Attempt to detect a close/fcntl race and recover by releasing the
2401 * lock that was just acquired. There is no need to do that when we're
2402 * unlocking though, or for OFD locks.
2404 if (!error && file_lock->fl_type != F_UNLCK &&
2405 !(file_lock->fl_flags & FL_OFDLCK)) {
2407 * We need that spin_lock here - it prevents reordering between
2408 * update of i_flctx->flc_posix and check for it done in
2409 * close(). rcu_read_lock() wouldn't do.
2411 spin_lock(¤t->files->file_lock);
2413 spin_unlock(¤t->files->file_lock);
2415 file_lock->fl_type = F_UNLCK;
2416 error = do_lock_file_wait(filp, cmd, file_lock);
2417 WARN_ON_ONCE(error);
2422 locks_free_lock(file_lock);
2425 #endif /* BITS_PER_LONG == 32 */
2428 * This function is called when the file is being removed
2429 * from the task's fd array. POSIX locks belonging to this task
2430 * are deleted at this time.
2432 void locks_remove_posix(struct file *filp, fl_owner_t owner)
2435 struct inode *inode = locks_inode(filp);
2436 struct file_lock lock;
2437 struct file_lock_context *ctx;
2440 * If there are no locks held on this file, we don't need to call
2441 * posix_lock_file(). Another process could be setting a lock on this
2442 * file at the same time, but we wouldn't remove that lock anyway.
2444 ctx = smp_load_acquire(&inode->i_flctx);
2445 if (!ctx || list_empty(&ctx->flc_posix))
2448 lock.fl_type = F_UNLCK;
2449 lock.fl_flags = FL_POSIX | FL_CLOSE;
2451 lock.fl_end = OFFSET_MAX;
2452 lock.fl_owner = owner;
2453 lock.fl_pid = current->tgid;
2454 lock.fl_file = filp;
2456 lock.fl_lmops = NULL;
2458 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
2460 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2461 lock.fl_ops->fl_release_private(&lock);
2462 trace_locks_remove_posix(inode, &lock, error);
2465 EXPORT_SYMBOL(locks_remove_posix);
2467 /* The i_flctx must be valid when calling into here */
2469 locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
2471 struct file_lock fl = {
2473 .fl_pid = current->tgid,
2475 .fl_flags = FL_FLOCK,
2477 .fl_end = OFFSET_MAX,
2479 struct inode *inode = locks_inode(filp);
2481 if (list_empty(&flctx->flc_flock))
2484 if (filp->f_op->flock && is_remote_lock(filp))
2485 filp->f_op->flock(filp, F_SETLKW, &fl);
2487 flock_lock_inode(inode, &fl);
2489 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2490 fl.fl_ops->fl_release_private(&fl);
2493 /* The i_flctx must be valid when calling into here */
2495 locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
2497 struct file_lock *fl, *tmp;
2500 if (list_empty(&ctx->flc_lease))
2503 spin_lock(&ctx->flc_lock);
2504 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
2505 if (filp == fl->fl_file)
2506 lease_modify(fl, F_UNLCK, &dispose);
2507 spin_unlock(&ctx->flc_lock);
2508 locks_dispose_list(&dispose);
2512 * This function is called on the last close of an open file.
2514 void locks_remove_file(struct file *filp)
2516 struct file_lock_context *ctx;
2518 ctx = smp_load_acquire(&locks_inode(filp)->i_flctx);
2522 /* remove any OFD locks */
2523 locks_remove_posix(filp, filp);
2525 /* remove flock locks */
2526 locks_remove_flock(filp, ctx);
2528 /* remove any leases */
2529 locks_remove_lease(filp, ctx);
2533 * posix_unblock_lock - stop waiting for a file lock
2534 * @waiter: the lock which was waiting
2536 * lockd needs to block waiting for locks.
2539 posix_unblock_lock(struct file_lock *waiter)
2543 spin_lock(&blocked_lock_lock);
2544 if (waiter->fl_next)
2545 __locks_delete_block(waiter);
2548 spin_unlock(&blocked_lock_lock);
2551 EXPORT_SYMBOL(posix_unblock_lock);
2554 * vfs_cancel_lock - file byte range unblock lock
2555 * @filp: The file to apply the unblock to
2556 * @fl: The lock to be unblocked
2558 * Used by lock managers to cancel blocked requests
2560 int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2562 if (filp->f_op->lock && is_remote_lock(filp))
2563 return filp->f_op->lock(filp, F_CANCELLK, fl);
2567 EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2569 #ifdef CONFIG_PROC_FS
2570 #include <linux/proc_fs.h>
2571 #include <linux/seq_file.h>
2573 struct locks_iterator {
2578 static void lock_get_status(struct seq_file *f, struct file_lock *fl,
2579 loff_t id, char *pfx)
2581 struct inode *inode = NULL;
2582 unsigned int fl_pid;
2585 fl_pid = pid_vnr(fl->fl_nspid);
2587 fl_pid = fl->fl_pid;
2589 if (fl->fl_file != NULL)
2590 inode = locks_inode(fl->fl_file);
2592 seq_printf(f, "%lld:%s ", id, pfx);
2594 if (fl->fl_flags & FL_ACCESS)
2595 seq_puts(f, "ACCESS");
2596 else if (IS_OFDLCK(fl))
2597 seq_puts(f, "OFDLCK");
2599 seq_puts(f, "POSIX ");
2601 seq_printf(f, " %s ",
2602 (inode == NULL) ? "*NOINODE*" :
2603 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
2604 } else if (IS_FLOCK(fl)) {
2605 if (fl->fl_type & LOCK_MAND) {
2606 seq_puts(f, "FLOCK MSNFS ");
2608 seq_puts(f, "FLOCK ADVISORY ");
2610 } else if (IS_LEASE(fl)) {
2611 if (fl->fl_flags & FL_DELEG)
2612 seq_puts(f, "DELEG ");
2614 seq_puts(f, "LEASE ");
2616 if (lease_breaking(fl))
2617 seq_puts(f, "BREAKING ");
2618 else if (fl->fl_file)
2619 seq_puts(f, "ACTIVE ");
2621 seq_puts(f, "BREAKER ");
2623 seq_puts(f, "UNKNOWN UNKNOWN ");
2625 if (fl->fl_type & LOCK_MAND) {
2626 seq_printf(f, "%s ",
2627 (fl->fl_type & LOCK_READ)
2628 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2629 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2631 seq_printf(f, "%s ",
2632 (lease_breaking(fl))
2633 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2634 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
2637 /* userspace relies on this representation of dev_t */
2638 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
2639 MAJOR(inode->i_sb->s_dev),
2640 MINOR(inode->i_sb->s_dev), inode->i_ino);
2642 seq_printf(f, "%d <none>:0 ", fl_pid);
2645 if (fl->fl_end == OFFSET_MAX)
2646 seq_printf(f, "%Ld EOF\n", fl->fl_start);
2648 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
2650 seq_puts(f, "0 EOF\n");
2654 static int locks_show(struct seq_file *f, void *v)
2656 struct locks_iterator *iter = f->private;
2657 struct file_lock *fl, *bfl;
2659 fl = hlist_entry(v, struct file_lock, fl_link);
2661 lock_get_status(f, fl, iter->li_pos, "");
2663 list_for_each_entry(bfl, &fl->fl_block, fl_block)
2664 lock_get_status(f, bfl, iter->li_pos, " ->");
2669 static void __show_fd_locks(struct seq_file *f,
2670 struct list_head *head, int *id,
2671 struct file *filp, struct files_struct *files)
2673 struct file_lock *fl;
2675 list_for_each_entry(fl, head, fl_list) {
2677 if (filp != fl->fl_file)
2679 if (fl->fl_owner != files &&
2680 fl->fl_owner != filp)
2684 seq_puts(f, "lock:\t");
2685 lock_get_status(f, fl, *id, "");
2689 void show_fd_locks(struct seq_file *f,
2690 struct file *filp, struct files_struct *files)
2692 struct inode *inode = locks_inode(filp);
2693 struct file_lock_context *ctx;
2696 ctx = smp_load_acquire(&inode->i_flctx);
2700 spin_lock(&ctx->flc_lock);
2701 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2702 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2703 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2704 spin_unlock(&ctx->flc_lock);
2707 static void *locks_start(struct seq_file *f, loff_t *pos)
2708 __acquires(&blocked_lock_lock)
2710 struct locks_iterator *iter = f->private;
2712 iter->li_pos = *pos + 1;
2713 lg_global_lock(&file_lock_lglock);
2714 spin_lock(&blocked_lock_lock);
2715 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
2718 static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2720 struct locks_iterator *iter = f->private;
2723 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
2726 static void locks_stop(struct seq_file *f, void *v)
2727 __releases(&blocked_lock_lock)
2729 spin_unlock(&blocked_lock_lock);
2730 lg_global_unlock(&file_lock_lglock);
2733 static const struct seq_operations locks_seq_operations = {
2734 .start = locks_start,
2740 static int locks_open(struct inode *inode, struct file *filp)
2742 return seq_open_private(filp, &locks_seq_operations,
2743 sizeof(struct locks_iterator));
2746 static const struct file_operations proc_locks_operations = {
2749 .llseek = seq_lseek,
2750 .release = seq_release_private,
2753 static int __init proc_locks_init(void)
2755 proc_create("locks", 0, NULL, &proc_locks_operations);
2758 fs_initcall(proc_locks_init);
2761 static int __init filelock_init(void)
2765 flctx_cache = kmem_cache_create("file_lock_ctx",
2766 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2768 filelock_cache = kmem_cache_create("file_lock_cache",
2769 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2771 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2773 for_each_possible_cpu(i)
2774 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2779 core_initcall(filelock_init);