blob: d3d558ba4da7966de9699aeb98b2630bd7c6854e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/locks.c
3 *
4 * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
5 * Doug Evans (dje@spiff.uucp), August 07, 1992
6 *
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.
11 *
12 * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
13 * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
14 *
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
18 *
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
26 *
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
30 *
31 * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
32 *
33 * FL_POSIX locks are created with calls to fcntl() and lockf() through the
34 * fcntl() system call. They have the semantics described above.
35 *
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.
39 *
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
44 * unlocked).
45 *
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
51 *
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.
55 *
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.
60 *
61 * Initial implementation of mandatory locks. SunOS turned out to be
62 * a rotten model, so I implemented the "obvious" semantics.
Paul Bolle395cf962011-08-15 02:02:26 +020063 * See 'Documentation/filesystems/mandatory-locking.txt' for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
65 *
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
69 * Manual, Section 2.
70 * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
71 *
72 * Tidied up block list handling. Added '/proc/locks' interface.
73 * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
74 *
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.
78 *
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.
84 *
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.
88 *
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.
93 *
94 * Made the block list a circular list to minimise searching in the list.
95 * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
96 *
97 * Made mandatory locking a mount option. Default is not to allow mandatory
98 * locking.
99 * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
100 *
101 * Some adaptations for NFS support.
102 * Olaf Kirch (okir@monad.swb.de), Dec 1996,
103 *
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.
106 *
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.
111 *
112 * Leases and LOCK_MAND
113 * Matthew Wilcox <willy@debian.org>, June, 2000.
114 * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
115 */
116
117#include <linux/capability.h>
118#include <linux/file.h>
Al Viro9f3acc32008-04-24 07:44:08 -0400119#include <linux/fdtable.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120#include <linux/fs.h>
121#include <linux/init.h>
122#include <linux/module.h>
123#include <linux/security.h>
124#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125#include <linux/syscalls.h>
126#include <linux/time.h>
Dipankar Sarma4fb3a532005-09-16 19:28:13 -0700127#include <linux/rcupdate.h>
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000128#include <linux/pid_namespace.h>
Jeff Layton48f74182013-06-21 08:58:18 -0400129#include <linux/hashtable.h>
Jeff Layton7012b022013-06-21 08:58:22 -0400130#include <linux/percpu.h>
131#include <linux/lglock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Jeff Layton62af4f12014-05-09 14:13:05 -0400133#define CREATE_TRACE_POINTS
134#include <trace/events/filelock.h>
135
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136#include <asm/uaccess.h>
137
138#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
139#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
Christoph Hellwig11afe9f2015-01-21 19:17:03 +0100140#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400141#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400143static bool lease_breaking(struct file_lock *fl)
144{
J. Bruce Fields778fc542011-07-26 18:25:49 -0400145 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
146}
147
148static int target_leasetype(struct file_lock *fl)
149{
150 if (fl->fl_flags & FL_UNLOCK_PENDING)
151 return F_UNLCK;
152 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
153 return F_RDLCK;
154 return fl->fl_type;
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400155}
156
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157int leases_enable = 1;
158int lease_break_time = 45;
159
Jeff Layton1c8c6012013-06-21 08:58:15 -0400160/*
Jeff Layton7012b022013-06-21 08:58:22 -0400161 * The global file_lock_list is only used for displaying /proc/locks, so we
162 * keep a list on each CPU, with each list protected by its own spinlock via
163 * the file_lock_lglock. Note that alterations to the list also require that
Jeff Layton6109c852015-01-16 15:05:57 -0500164 * the relevant flc_lock is held.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400165 */
Jeff Layton7012b022013-06-21 08:58:22 -0400166DEFINE_STATIC_LGLOCK(file_lock_lglock);
167static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
Jeff Layton88974692013-06-21 08:58:14 -0400168
Jeff Layton1c8c6012013-06-21 08:58:15 -0400169/*
Jeff Layton48f74182013-06-21 08:58:18 -0400170 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
Jeff Layton7b2296a2013-06-21 08:58:20 -0400171 * It is protected by blocked_lock_lock.
Jeff Layton48f74182013-06-21 08:58:18 -0400172 *
173 * We hash locks by lockowner in order to optimize searching for the lock a
174 * particular lockowner is waiting on.
175 *
176 * FIXME: make this value scale via some heuristic? We generally will want more
177 * buckets when we have more lockowners holding locks, but that's a little
178 * difficult to determine without knowing what the workload will look like.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400179 */
Jeff Layton48f74182013-06-21 08:58:18 -0400180#define BLOCKED_HASH_BITS 7
181static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
Jeff Layton88974692013-06-21 08:58:14 -0400182
Jeff Layton1c8c6012013-06-21 08:58:15 -0400183/*
Jeff Layton7b2296a2013-06-21 08:58:20 -0400184 * This lock protects the blocked_hash. Generally, if you're accessing it, you
185 * want to be holding this lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400186 *
187 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
188 * pointer for file_lock structures that are acting as lock requests (in
189 * contrast to those that are acting as records of acquired locks).
190 *
191 * Note that when we acquire this lock in order to change the above fields,
Jeff Layton6109c852015-01-16 15:05:57 -0500192 * we often hold the flc_lock as well. In certain cases, when reading the fields
Jeff Layton1c8c6012013-06-21 08:58:15 -0400193 * protected by this lock, we can skip acquiring it iff we already hold the
Jeff Layton6109c852015-01-16 15:05:57 -0500194 * flc_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400195 *
196 * In particular, adding an entry to the fl_block list requires that you hold
Jeff Layton6109c852015-01-16 15:05:57 -0500197 * both the flc_lock and the blocked_lock_lock (acquired in that order).
198 * Deleting an entry from the list however only requires the file_lock_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400199 */
Jeff Layton7b2296a2013-06-21 08:58:20 -0400200static DEFINE_SPINLOCK(blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
Jeff Layton4a075e32015-01-16 15:05:54 -0500202static struct kmem_cache *flctx_cache __read_mostly;
Christoph Lametere18b8902006-12-06 20:33:20 -0800203static struct kmem_cache *filelock_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Jeff Layton4a075e32015-01-16 15:05:54 -0500205static struct file_lock_context *
Jeff Layton5c1c6692015-04-03 09:04:03 -0400206locks_get_lock_context(struct inode *inode, int type)
Jeff Layton4a075e32015-01-16 15:05:54 -0500207{
208 struct file_lock_context *new;
209
Jeff Layton5c1c6692015-04-03 09:04:03 -0400210 if (likely(inode->i_flctx) || type == F_UNLCK)
Jeff Layton4a075e32015-01-16 15:05:54 -0500211 goto out;
212
213 new = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
214 if (!new)
215 goto out;
216
Jeff Layton6109c852015-01-16 15:05:57 -0500217 spin_lock_init(&new->flc_lock);
Jeff Layton4a075e32015-01-16 15:05:54 -0500218 INIT_LIST_HEAD(&new->flc_flock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500219 INIT_LIST_HEAD(&new->flc_posix);
Jeff Layton8634b512015-01-16 15:05:55 -0500220 INIT_LIST_HEAD(&new->flc_lease);
Jeff Layton4a075e32015-01-16 15:05:54 -0500221
222 /*
223 * Assign the pointer if it's not already assigned. If it is, then
224 * free the context we just allocated.
225 */
Jeff Layton0429c2b2015-04-03 09:04:04 -0400226 if (cmpxchg(&inode->i_flctx, NULL, new))
Jeff Layton4a075e32015-01-16 15:05:54 -0500227 kmem_cache_free(flctx_cache, new);
228out:
229 return inode->i_flctx;
230}
231
232void
233locks_free_lock_context(struct file_lock_context *ctx)
234{
235 if (ctx) {
236 WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500237 WARN_ON_ONCE(!list_empty(&ctx->flc_posix));
Jeff Layton8634b512015-01-16 15:05:55 -0500238 WARN_ON_ONCE(!list_empty(&ctx->flc_lease));
Jeff Layton4a075e32015-01-16 15:05:54 -0500239 kmem_cache_free(flctx_cache, ctx);
240 }
241}
242
Miklos Szerediee19cc42011-07-07 13:06:09 +0200243static void locks_init_lock_heads(struct file_lock *fl)
Miklos Szeredia51cb912011-07-06 12:33:55 +0200244{
Jeff Layton139ca042013-06-21 08:58:17 -0400245 INIT_HLIST_NODE(&fl->fl_link);
Jeff Layton6dee60f2015-01-16 15:05:54 -0500246 INIT_LIST_HEAD(&fl->fl_list);
Miklos Szerediee19cc42011-07-07 13:06:09 +0200247 INIT_LIST_HEAD(&fl->fl_block);
248 init_waitqueue_head(&fl->fl_wait);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200249}
250
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251/* Allocate an empty lock structure. */
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200252struct file_lock *locks_alloc_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200254 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200255
256 if (fl)
Miklos Szerediee19cc42011-07-07 13:06:09 +0200257 locks_init_lock_heads(fl);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200258
259 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260}
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200261EXPORT_SYMBOL_GPL(locks_alloc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500263void locks_release_private(struct file_lock *fl)
Trond Myklebust47831f32006-03-20 13:44:05 -0500264{
265 if (fl->fl_ops) {
266 if (fl->fl_ops->fl_release_private)
267 fl->fl_ops->fl_release_private(fl);
268 fl->fl_ops = NULL;
269 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500270
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400271 if (fl->fl_lmops) {
Jeff Laytoncae80b32015-04-03 09:04:04 -0400272 if (fl->fl_lmops->lm_put_owner) {
273 fl->fl_lmops->lm_put_owner(fl->fl_owner);
274 fl->fl_owner = NULL;
275 }
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400276 fl->fl_lmops = NULL;
277 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500278}
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500279EXPORT_SYMBOL_GPL(locks_release_private);
Trond Myklebust47831f32006-03-20 13:44:05 -0500280
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281/* Free a lock which is not in use. */
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400282void locks_free_lock(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283{
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800284 BUG_ON(waitqueue_active(&fl->fl_wait));
Jeff Layton6dee60f2015-01-16 15:05:54 -0500285 BUG_ON(!list_empty(&fl->fl_list));
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800286 BUG_ON(!list_empty(&fl->fl_block));
Jeff Layton139ca042013-06-21 08:58:17 -0400287 BUG_ON(!hlist_unhashed(&fl->fl_link));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
Trond Myklebust47831f32006-03-20 13:44:05 -0500289 locks_release_private(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 kmem_cache_free(filelock_cache, fl);
291}
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400292EXPORT_SYMBOL(locks_free_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Jeff Laytoned9814d2014-08-11 14:20:31 -0400294static void
295locks_dispose_list(struct list_head *dispose)
296{
297 struct file_lock *fl;
298
299 while (!list_empty(dispose)) {
Jeff Layton6dee60f2015-01-16 15:05:54 -0500300 fl = list_first_entry(dispose, struct file_lock, fl_list);
301 list_del_init(&fl->fl_list);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400302 locks_free_lock(fl);
303 }
304}
305
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306void locks_init_lock(struct file_lock *fl)
307{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200308 memset(fl, 0, sizeof(struct file_lock));
309 locks_init_lock_heads(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310}
311
312EXPORT_SYMBOL(locks_init_lock);
313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314/*
315 * Initialize a new lock from an existing file_lock structure.
316 */
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400317void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318{
319 new->fl_owner = fl->fl_owner;
320 new->fl_pid = fl->fl_pid;
Trond Myklebust09969052006-03-20 13:44:38 -0500321 new->fl_file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 new->fl_flags = fl->fl_flags;
323 new->fl_type = fl->fl_type;
324 new->fl_start = fl->fl_start;
325 new->fl_end = fl->fl_end;
Kinglong Meef3282962014-08-22 10:18:43 -0400326 new->fl_lmops = fl->fl_lmops;
Trond Myklebust09969052006-03-20 13:44:38 -0500327 new->fl_ops = NULL;
Kinglong Meef3282962014-08-22 10:18:43 -0400328
329 if (fl->fl_lmops) {
330 if (fl->fl_lmops->lm_get_owner)
Jeff Laytoncae80b32015-04-03 09:04:04 -0400331 fl->fl_lmops->lm_get_owner(fl->fl_owner);
Kinglong Meef3282962014-08-22 10:18:43 -0400332 }
Trond Myklebust09969052006-03-20 13:44:38 -0500333}
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400334EXPORT_SYMBOL(locks_copy_conflock);
Trond Myklebust09969052006-03-20 13:44:38 -0500335
336void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
337{
Jeff Layton566709b2014-08-11 14:09:35 -0400338 /* "new" must be a freshly-initialized lock */
339 WARN_ON_ONCE(new->fl_ops);
Trond Myklebust09969052006-03-20 13:44:38 -0500340
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400341 locks_copy_conflock(new, fl);
Kinglong Meef3282962014-08-22 10:18:43 -0400342
Trond Myklebust09969052006-03-20 13:44:38 -0500343 new->fl_file = fl->fl_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 new->fl_ops = fl->fl_ops;
Trond Myklebust47831f32006-03-20 13:44:05 -0500345
Kinglong Meef3282962014-08-22 10:18:43 -0400346 if (fl->fl_ops) {
347 if (fl->fl_ops->fl_copy_lock)
348 fl->fl_ops->fl_copy_lock(new, fl);
349 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350}
351
352EXPORT_SYMBOL(locks_copy_lock);
353
354static inline int flock_translate_cmd(int cmd) {
355 if (cmd & LOCK_MAND)
356 return cmd & (LOCK_MAND | LOCK_RW);
357 switch (cmd) {
358 case LOCK_SH:
359 return F_RDLCK;
360 case LOCK_EX:
361 return F_WRLCK;
362 case LOCK_UN:
363 return F_UNLCK;
364 }
365 return -EINVAL;
366}
367
368/* Fill in a file_lock structure with an appropriate FLOCK lock. */
Jeff Layton6e129d002014-09-04 10:25:06 -0400369static struct file_lock *
370flock_make_lock(struct file *filp, unsigned int cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371{
372 struct file_lock *fl;
373 int type = flock_translate_cmd(cmd);
Jeff Layton6e129d002014-09-04 10:25:06 -0400374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 if (type < 0)
Jeff Layton6e129d002014-09-04 10:25:06 -0400376 return ERR_PTR(type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
378 fl = locks_alloc_lock();
379 if (fl == NULL)
Jeff Layton6e129d002014-09-04 10:25:06 -0400380 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
382 fl->fl_file = filp;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +0200383 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 fl->fl_pid = current->tgid;
385 fl->fl_flags = FL_FLOCK;
386 fl->fl_type = type;
387 fl->fl_end = OFFSET_MAX;
388
Jeff Layton6e129d002014-09-04 10:25:06 -0400389 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390}
391
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400392static int assign_type(struct file_lock *fl, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393{
394 switch (type) {
395 case F_RDLCK:
396 case F_WRLCK:
397 case F_UNLCK:
398 fl->fl_type = type;
399 break;
400 default:
401 return -EINVAL;
402 }
403 return 0;
404}
405
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500406static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
407 struct flock64 *l)
408{
409 switch (l->l_whence) {
410 case SEEK_SET:
411 fl->fl_start = 0;
412 break;
413 case SEEK_CUR:
414 fl->fl_start = filp->f_pos;
415 break;
416 case SEEK_END:
417 fl->fl_start = i_size_read(file_inode(filp));
418 break;
419 default:
420 return -EINVAL;
421 }
422 if (l->l_start > OFFSET_MAX - fl->fl_start)
423 return -EOVERFLOW;
424 fl->fl_start += l->l_start;
425 if (fl->fl_start < 0)
426 return -EINVAL;
427
428 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
429 POSIX-2001 defines it. */
430 if (l->l_len > 0) {
431 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
432 return -EOVERFLOW;
433 fl->fl_end = fl->fl_start + l->l_len - 1;
434
435 } else if (l->l_len < 0) {
436 if (fl->fl_start + l->l_len < 0)
437 return -EINVAL;
438 fl->fl_end = fl->fl_start - 1;
439 fl->fl_start += l->l_len;
440 } else
441 fl->fl_end = OFFSET_MAX;
442
443 fl->fl_owner = current->files;
444 fl->fl_pid = current->tgid;
445 fl->fl_file = filp;
446 fl->fl_flags = FL_POSIX;
447 fl->fl_ops = NULL;
448 fl->fl_lmops = NULL;
449
450 return assign_type(fl, l->l_type);
451}
452
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
454 * style lock.
455 */
456static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
457 struct flock *l)
458{
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500459 struct flock64 ll = {
460 .l_type = l->l_type,
461 .l_whence = l->l_whence,
462 .l_start = l->l_start,
463 .l_len = l->l_len,
464 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500466 return flock64_to_posix_lock(filp, fl, &ll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467}
468
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469/* default lease lock manager operations */
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400470static bool
471lease_break_callback(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472{
473 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400474 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475}
476
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400477static void
478lease_setup(struct file_lock *fl, void **priv)
479{
480 struct file *filp = fl->fl_file;
481 struct fasync_struct *fa = *priv;
482
483 /*
484 * fasync_insert_entry() returns the old entry if any. If there was no
485 * old entry, then it used "priv" and inserted it into the fasync list.
486 * Clear the pointer to indicate that it shouldn't be freed.
487 */
488 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
489 *priv = NULL;
490
491 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
492}
493
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700494static const struct lock_manager_operations lease_manager_ops = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400495 .lm_break = lease_break_callback,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400496 .lm_change = lease_modify,
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400497 .lm_setup = lease_setup,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498};
499
500/*
501 * Initialize a lease, use the default lock manager operations
502 */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400503static int lease_init(struct file *filp, long type, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 {
Trond Myklebust75dff552006-05-07 23:02:42 -0400505 if (assign_type(fl, type) != 0)
506 return -EINVAL;
507
Jeff Layton7ca76312014-09-01 19:04:48 -0400508 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 fl->fl_pid = current->tgid;
510
511 fl->fl_file = filp;
512 fl->fl_flags = FL_LEASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 fl->fl_start = 0;
514 fl->fl_end = OFFSET_MAX;
515 fl->fl_ops = NULL;
516 fl->fl_lmops = &lease_manager_ops;
517 return 0;
518}
519
520/* Allocate a file_lock initialised to this type of lease */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400521static struct file_lock *lease_alloc(struct file *filp, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522{
523 struct file_lock *fl = locks_alloc_lock();
Trond Myklebust75dff552006-05-07 23:02:42 -0400524 int error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525
526 if (fl == NULL)
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500527 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528
529 error = lease_init(filp, type, fl);
Trond Myklebust75dff552006-05-07 23:02:42 -0400530 if (error) {
531 locks_free_lock(fl);
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500532 return ERR_PTR(error);
Trond Myklebust75dff552006-05-07 23:02:42 -0400533 }
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500534 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535}
536
537/* Check if two locks overlap each other.
538 */
539static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
540{
541 return ((fl1->fl_end >= fl2->fl_start) &&
542 (fl2->fl_end >= fl1->fl_start));
543}
544
545/*
546 * Check whether two locks have the same owner.
547 */
Matt Mackall33443c42006-01-08 01:05:22 -0800548static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549{
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400550 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 return fl2->fl_lmops == fl1->fl_lmops &&
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400552 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 return fl1->fl_owner == fl2->fl_owner;
554}
555
Jeff Layton6109c852015-01-16 15:05:57 -0500556/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500557static void locks_insert_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400558{
Jeff Layton7012b022013-06-21 08:58:22 -0400559 lg_local_lock(&file_lock_lglock);
560 fl->fl_link_cpu = smp_processor_id();
561 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
562 lg_local_unlock(&file_lock_lglock);
Jeff Layton88974692013-06-21 08:58:14 -0400563}
564
Jeff Layton6109c852015-01-16 15:05:57 -0500565/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500566static void locks_delete_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400567{
Jeff Layton7012b022013-06-21 08:58:22 -0400568 /*
569 * Avoid taking lock if already unhashed. This is safe since this check
Jeff Layton6109c852015-01-16 15:05:57 -0500570 * is done while holding the flc_lock, and new insertions into the list
Jeff Layton7012b022013-06-21 08:58:22 -0400571 * also require that it be held.
572 */
573 if (hlist_unhashed(&fl->fl_link))
574 return;
575 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
Jeff Layton139ca042013-06-21 08:58:17 -0400576 hlist_del_init(&fl->fl_link);
Jeff Layton7012b022013-06-21 08:58:22 -0400577 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
Jeff Layton88974692013-06-21 08:58:14 -0400578}
579
Jeff Layton3999e492013-06-21 08:58:19 -0400580static unsigned long
581posix_owner_key(struct file_lock *fl)
582{
583 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
584 return fl->fl_lmops->lm_owner_key(fl);
585 return (unsigned long)fl->fl_owner;
586}
587
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500588static void locks_insert_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400589{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400590 lockdep_assert_held(&blocked_lock_lock);
591
Jeff Layton3999e492013-06-21 08:58:19 -0400592 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
Jeff Layton88974692013-06-21 08:58:14 -0400593}
594
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500595static void locks_delete_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400596{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400597 lockdep_assert_held(&blocked_lock_lock);
598
Jeff Layton48f74182013-06-21 08:58:18 -0400599 hash_del(&waiter->fl_link);
Jeff Layton88974692013-06-21 08:58:14 -0400600}
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602/* Remove waiter from blocker's block list.
603 * When blocker ends up pointing to itself then the list is empty.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400604 *
Jeff Layton7b2296a2013-06-21 08:58:20 -0400605 * Must be called with blocked_lock_lock held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 */
Matt Mackall33443c42006-01-08 01:05:22 -0800607static void __locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608{
Jeff Layton88974692013-06-21 08:58:14 -0400609 locks_delete_global_blocked(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 list_del_init(&waiter->fl_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 waiter->fl_next = NULL;
612}
613
Jeff Layton1a9e64a2013-06-21 08:58:10 -0400614static void locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400616 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 __locks_delete_block(waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400618 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619}
620
621/* Insert waiter into blocker's block list.
622 * We use a circular list so that processes can be easily woken up in
623 * the order they blocked. The documentation doesn't require this but
624 * it seems like the reasonable thing to do.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400625 *
Jeff Layton6109c852015-01-16 15:05:57 -0500626 * Must be called with both the flc_lock and blocked_lock_lock held. The
627 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
628 * that the flc_lock is also held on insertions we can avoid taking the
629 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400631static void __locks_insert_block(struct file_lock *blocker,
632 struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633{
J. Bruce Fields6dc0fe82006-03-26 01:37:24 -0800634 BUG_ON(!list_empty(&waiter->fl_block));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 waiter->fl_next = blocker;
Jeff Layton88974692013-06-21 08:58:14 -0400636 list_add_tail(&waiter->fl_block, &blocker->fl_block);
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400637 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
Jeff Layton1c8c6012013-06-21 08:58:15 -0400638 locks_insert_global_blocked(waiter);
639}
640
Jeff Layton6109c852015-01-16 15:05:57 -0500641/* Must be called with flc_lock held. */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400642static void locks_insert_block(struct file_lock *blocker,
643 struct file_lock *waiter)
644{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400645 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400646 __locks_insert_block(blocker, waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400647 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648}
649
Jeff Layton1cb36012013-06-21 08:58:12 -0400650/*
651 * Wake up processes blocked waiting for blocker.
652 *
Jeff Layton6109c852015-01-16 15:05:57 -0500653 * Must be called with the inode->flc_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 */
655static void locks_wake_up_blocks(struct file_lock *blocker)
656{
Jeff Layton4e8c7652013-06-21 08:58:16 -0400657 /*
658 * Avoid taking global lock if list is empty. This is safe since new
Jeff Layton6109c852015-01-16 15:05:57 -0500659 * blocked requests are only added to the list under the flc_lock, and
660 * the flc_lock is always held here. Note that removal from the fl_block
661 * list does not require the flc_lock, so we must recheck list_empty()
Jeff Layton7b2296a2013-06-21 08:58:20 -0400662 * after acquiring the blocked_lock_lock.
Jeff Layton4e8c7652013-06-21 08:58:16 -0400663 */
664 if (list_empty(&blocker->fl_block))
665 return;
666
Jeff Layton7b2296a2013-06-21 08:58:20 -0400667 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 while (!list_empty(&blocker->fl_block)) {
Pavel Emelyanovf0c1cd02007-09-19 16:44:07 +0400669 struct file_lock *waiter;
670
671 waiter = list_first_entry(&blocker->fl_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 struct file_lock, fl_block);
673 __locks_delete_block(waiter);
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400674 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
675 waiter->fl_lmops->lm_notify(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 else
677 wake_up(&waiter->fl_wait);
678 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400679 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680}
681
Jeff Layton5263e312015-01-16 15:05:55 -0500682static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500683locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
Jeff Layton5263e312015-01-16 15:05:55 -0500684{
685 fl->fl_nspid = get_pid(task_tgid(current));
686 list_add_tail(&fl->fl_list, before);
687 locks_insert_global_locks(fl);
688}
689
Jeff Layton8634b512015-01-16 15:05:55 -0500690static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500691locks_unlink_lock_ctx(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692{
Jeff Layton88974692013-06-21 08:58:14 -0400693 locks_delete_global_locks(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500694 list_del_init(&fl->fl_list);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000695 if (fl->fl_nspid) {
696 put_pid(fl->fl_nspid);
697 fl->fl_nspid = NULL;
698 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 locks_wake_up_blocks(fl);
Jeff Layton24cbe782014-02-03 12:13:06 -0500700}
701
Jeff Layton5263e312015-01-16 15:05:55 -0500702static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500703locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
Jeff Layton5263e312015-01-16 15:05:55 -0500704{
Jeff Laytone084c1b2015-02-16 14:32:03 -0500705 locks_unlink_lock_ctx(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500706 if (dispose)
707 list_add(&fl->fl_list, dispose);
708 else
709 locks_free_lock(fl);
Jeff Layton5263e312015-01-16 15:05:55 -0500710}
711
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
713 * checks for shared/exclusive status of overlapping locks.
714 */
715static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
716{
717 if (sys_fl->fl_type == F_WRLCK)
718 return 1;
719 if (caller_fl->fl_type == F_WRLCK)
720 return 1;
721 return 0;
722}
723
724/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
725 * checking before calling the locks_conflict().
726 */
727static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
728{
729 /* POSIX locks owned by the same process do not conflict with
730 * each other.
731 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400732 if (posix_same_owner(caller_fl, sys_fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 return (0);
734
735 /* Check whether they overlap */
736 if (!locks_overlap(caller_fl, sys_fl))
737 return 0;
738
739 return (locks_conflict(caller_fl, sys_fl));
740}
741
742/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
743 * checking before calling the locks_conflict().
744 */
745static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
746{
747 /* FLOCK locks referring to the same filp do not conflict with
748 * each other.
749 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400750 if (caller_fl->fl_file == sys_fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 return (0);
752 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
753 return 0;
754
755 return (locks_conflict(caller_fl, sys_fl));
756}
757
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400758void
Marc Eshel9d6a8c52007-02-21 00:55:18 -0500759posix_test_lock(struct file *filp, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760{
761 struct file_lock *cfl;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500762 struct file_lock_context *ctx;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400763 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500765 ctx = inode->i_flctx;
766 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
J. Bruce Fields129a84d2007-05-10 18:38:43 -0400767 fl->fl_type = F_UNLCK;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500768 return;
769 }
770
Jeff Layton6109c852015-01-16 15:05:57 -0500771 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500772 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
773 if (posix_locks_conflict(fl, cfl)) {
774 locks_copy_conflock(fl, cfl);
775 if (cfl->fl_nspid)
776 fl->fl_pid = pid_vnr(cfl->fl_nspid);
777 goto out;
778 }
779 }
780 fl->fl_type = F_UNLCK;
781out:
Jeff Layton6109c852015-01-16 15:05:57 -0500782 spin_unlock(&ctx->flc_lock);
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400783 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785EXPORT_SYMBOL(posix_test_lock);
786
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400787/*
788 * Deadlock detection:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400790 * We attempt to detect deadlocks that are due purely to posix file
791 * locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400793 * We assume that a task can be waiting for at most one lock at a time.
794 * So for any acquired lock, the process holding that lock may be
795 * waiting on at most one other lock. That lock in turns may be held by
796 * someone waiting for at most one other lock. Given a requested lock
797 * caller_fl which is about to wait for a conflicting lock block_fl, we
798 * follow this chain of waiters to ensure we are not about to create a
799 * cycle.
J. Bruce Fields97855b42007-10-30 11:20:02 -0400800 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400801 * Since we do this before we ever put a process to sleep on a lock, we
802 * are ensured that there is never a cycle; that is what guarantees that
803 * the while() loop in posix_locks_deadlock() eventually completes.
804 *
805 * Note: the above assumption may not be true when handling lock
806 * requests from a broken NFS client. It may also fail in the presence
807 * of tasks (such as posix threads) sharing the same open file table.
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400808 * To handle those cases, we just bail out after a few iterations.
Jeff Layton57b65322014-02-03 12:13:09 -0500809 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400810 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
Jeff Layton57b65322014-02-03 12:13:09 -0500811 * Because the owner is not even nominally tied to a thread of
812 * execution, the deadlock detection below can't reasonably work well. Just
813 * skip it for those.
814 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400815 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
Jeff Layton57b65322014-02-03 12:13:09 -0500816 * locks that just checks for the case where two tasks are attempting to
817 * upgrade from read to write locks on the same inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 */
J. Bruce Fields97855b42007-10-30 11:20:02 -0400819
820#define MAX_DEADLK_ITERATIONS 10
821
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400822/* Find a lock that the owner of the given block_fl is blocking on. */
823static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
824{
825 struct file_lock *fl;
826
Jeff Layton3999e492013-06-21 08:58:19 -0400827 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400828 if (posix_same_owner(fl, block_fl))
829 return fl->fl_next;
830 }
831 return NULL;
832}
833
Jeff Layton7b2296a2013-06-21 08:58:20 -0400834/* Must be called with the blocked_lock_lock held! */
Adrian Bunkb0904e12006-06-23 02:05:13 -0700835static int posix_locks_deadlock(struct file_lock *caller_fl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 struct file_lock *block_fl)
837{
J. Bruce Fields97855b42007-10-30 11:20:02 -0400838 int i = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
Daniel Wagner663d5af2015-04-03 09:04:03 -0400840 lockdep_assert_held(&blocked_lock_lock);
841
Jeff Layton57b65322014-02-03 12:13:09 -0500842 /*
843 * This deadlock detector can't reasonably detect deadlocks with
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400844 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
Jeff Layton57b65322014-02-03 12:13:09 -0500845 */
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400846 if (IS_OFDLCK(caller_fl))
Jeff Layton57b65322014-02-03 12:13:09 -0500847 return 0;
848
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400849 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
850 if (i++ > MAX_DEADLK_ITERATIONS)
851 return 0;
852 if (posix_same_owner(caller_fl, block_fl))
853 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 }
855 return 0;
856}
857
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
J. Bruce Fields02888f42007-09-12 15:45:07 -0400859 * after any leases, but before any posix locks.
Trond Myklebustf475ae92006-06-29 16:38:32 -0400860 *
861 * Note that if called with an FL_EXISTS argument, the caller may determine
862 * whether or not a lock was successfully freed by testing the return
863 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 */
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400865static int flock_lock_inode(struct inode *inode, struct file_lock *request)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866{
Trond Myklebust993dfa82006-03-31 02:30:55 -0800867 struct file_lock *new_fl = NULL;
Jeff Layton5263e312015-01-16 15:05:55 -0500868 struct file_lock *fl;
869 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 int error = 0;
Jeff Layton5263e312015-01-16 15:05:55 -0500871 bool found = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400872 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873
Jeff Layton5c1c6692015-04-03 09:04:03 -0400874 ctx = locks_get_lock_context(inode, request->fl_type);
875 if (!ctx) {
876 if (request->fl_type != F_UNLCK)
877 return -ENOMEM;
878 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
879 }
Jeff Layton5263e312015-01-16 15:05:55 -0500880
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200881 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
882 new_fl = locks_alloc_lock();
883 if (!new_fl)
884 return -ENOMEM;
885 }
886
Jeff Layton6109c852015-01-16 15:05:57 -0500887 spin_lock(&ctx->flc_lock);
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400888 if (request->fl_flags & FL_ACCESS)
889 goto find_conflict;
Pavel Emelyanov84d535a2007-09-11 16:38:13 +0400890
Jeff Layton5263e312015-01-16 15:05:55 -0500891 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400892 if (request->fl_file != fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 continue;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800894 if (request->fl_type == fl->fl_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 goto out;
Jeff Layton5263e312015-01-16 15:05:55 -0500896 found = true;
Jeff Laytone084c1b2015-02-16 14:32:03 -0500897 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 break;
899 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900
Trond Myklebustf475ae92006-06-29 16:38:32 -0400901 if (request->fl_type == F_UNLCK) {
902 if ((request->fl_flags & FL_EXISTS) && !found)
903 error = -ENOENT;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800904 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -0400905 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400907find_conflict:
Jeff Layton5263e312015-01-16 15:05:55 -0500908 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Trond Myklebust993dfa82006-03-31 02:30:55 -0800909 if (!flock_locks_conflict(request, fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 continue;
911 error = -EAGAIN;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700912 if (!(request->fl_flags & FL_SLEEP))
913 goto out;
914 error = FILE_LOCK_DEFERRED;
915 locks_insert_block(fl, request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 goto out;
917 }
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400918 if (request->fl_flags & FL_ACCESS)
919 goto out;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800920 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -0500921 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800922 new_fl = NULL;
Kirill Korotaev9cedc192006-06-14 17:59:35 +0400923 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
925out:
Jeff Layton6109c852015-01-16 15:05:57 -0500926 spin_unlock(&ctx->flc_lock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800927 if (new_fl)
928 locks_free_lock(new_fl);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400929 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 return error;
931}
932
Marc Eshel150b3932007-01-18 16:15:35 -0500933static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500935 struct file_lock *fl, *tmp;
Miklos Szeredi39005d02006-06-23 02:05:10 -0700936 struct file_lock *new_fl = NULL;
937 struct file_lock *new_fl2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 struct file_lock *left = NULL;
939 struct file_lock *right = NULL;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500940 struct file_lock_context *ctx;
Jeff Laytonb9746ef2013-06-21 08:58:13 -0400941 int error;
942 bool added = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400943 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944
Jeff Layton5c1c6692015-04-03 09:04:03 -0400945 ctx = locks_get_lock_context(inode, request->fl_type);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500946 if (!ctx)
Jeff Layton5c1c6692015-04-03 09:04:03 -0400947 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500948
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 /*
950 * We may need two file_lock structures for this operation,
951 * so we get them in advance to avoid races.
Miklos Szeredi39005d02006-06-23 02:05:10 -0700952 *
953 * In some cases we can be sure, that no new locks will be needed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 */
Miklos Szeredi39005d02006-06-23 02:05:10 -0700955 if (!(request->fl_flags & FL_ACCESS) &&
956 (request->fl_type != F_UNLCK ||
957 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
958 new_fl = locks_alloc_lock();
959 new_fl2 = locks_alloc_lock();
960 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961
Jeff Layton6109c852015-01-16 15:05:57 -0500962 spin_lock(&ctx->flc_lock);
Jeff Layton1cb36012013-06-21 08:58:12 -0400963 /*
964 * New lock request. Walk all POSIX locks and look for conflicts. If
965 * there are any, either return error or put the request on the
Jeff Layton48f74182013-06-21 08:58:18 -0400966 * blocker's list of waiters and the global blocked_hash.
Jeff Layton1cb36012013-06-21 08:58:12 -0400967 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 if (request->fl_type != F_UNLCK) {
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500969 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 if (!posix_locks_conflict(request, fl))
971 continue;
Andy Adamson5842add2006-03-26 01:37:26 -0800972 if (conflock)
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400973 locks_copy_conflock(conflock, fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974 error = -EAGAIN;
975 if (!(request->fl_flags & FL_SLEEP))
976 goto out;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400977 /*
978 * Deadlock detection and insertion into the blocked
979 * locks list must be done while holding the same lock!
980 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 error = -EDEADLK;
Jeff Layton7b2296a2013-06-21 08:58:20 -0400982 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400983 if (likely(!posix_locks_deadlock(request, fl))) {
984 error = FILE_LOCK_DEFERRED;
985 __locks_insert_block(fl, request);
986 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400987 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 goto out;
989 }
990 }
991
992 /* If we're just looking for a conflict, we're done. */
993 error = 0;
994 if (request->fl_flags & FL_ACCESS)
995 goto out;
996
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500997 /* Find the first old lock with the same owner as the new lock */
998 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
999 if (posix_same_owner(request, fl))
1000 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 }
1002
Jeff Layton1cb36012013-06-21 08:58:12 -04001003 /* Process locks with this owner. */
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001004 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1005 if (!posix_same_owner(request, fl))
1006 break;
1007
1008 /* Detect adjacent or overlapping regions (if same lock type) */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 if (request->fl_type == fl->fl_type) {
Olaf Kirch449231d2005-08-25 16:25:35 -07001010 /* In all comparisons of start vs end, use
1011 * "start - 1" rather than "end + 1". If end
1012 * is OFFSET_MAX, end + 1 will become negative.
1013 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 if (fl->fl_end < request->fl_start - 1)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001015 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 /* If the next lock in the list has entirely bigger
1017 * addresses than the new one, insert the lock here.
1018 */
Olaf Kirch449231d2005-08-25 16:25:35 -07001019 if (fl->fl_start - 1 > request->fl_end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 break;
1021
1022 /* If we come here, the new and old lock are of the
1023 * same type and adjacent or overlapping. Make one
1024 * lock yielding from the lower start address of both
1025 * locks to the higher end address.
1026 */
1027 if (fl->fl_start > request->fl_start)
1028 fl->fl_start = request->fl_start;
1029 else
1030 request->fl_start = fl->fl_start;
1031 if (fl->fl_end < request->fl_end)
1032 fl->fl_end = request->fl_end;
1033 else
1034 request->fl_end = fl->fl_end;
1035 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001036 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 continue;
1038 }
1039 request = fl;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001040 added = true;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001041 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 /* Processing for different lock types is a bit
1043 * more complex.
1044 */
1045 if (fl->fl_end < request->fl_start)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001046 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 if (fl->fl_start > request->fl_end)
1048 break;
1049 if (request->fl_type == F_UNLCK)
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001050 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 if (fl->fl_start < request->fl_start)
1052 left = fl;
1053 /* If the next lock in the list has a higher end
1054 * address than the new one, insert the new one here.
1055 */
1056 if (fl->fl_end > request->fl_end) {
1057 right = fl;
1058 break;
1059 }
1060 if (fl->fl_start >= request->fl_start) {
1061 /* The new lock completely replaces an old
1062 * one (This may happen several times).
1063 */
1064 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001065 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 continue;
1067 }
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001068 /*
1069 * Replace the old lock with new_fl, and
1070 * remove the old one. It's safe to do the
1071 * insert here since we know that we won't be
1072 * using new_fl later, and that the lock is
1073 * just replacing an existing lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 */
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001075 error = -ENOLCK;
1076 if (!new_fl)
1077 goto out;
1078 locks_copy_lock(new_fl, request);
1079 request = new_fl;
1080 new_fl = NULL;
Jeff Laytone084c1b2015-02-16 14:32:03 -05001081 locks_insert_lock_ctx(request, &fl->fl_list);
1082 locks_delete_lock_ctx(fl, &dispose);
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001083 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 }
1085 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 }
1087
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001088 /*
Jeff Layton1cb36012013-06-21 08:58:12 -04001089 * The above code only modifies existing locks in case of merging or
1090 * replacing. If new lock(s) need to be inserted all modifications are
1091 * done below this, so it's safe yet to bail out.
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001092 */
1093 error = -ENOLCK; /* "no luck" */
1094 if (right && left == right && !new_fl2)
1095 goto out;
1096
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 error = 0;
1098 if (!added) {
Trond Myklebustf475ae92006-06-29 16:38:32 -04001099 if (request->fl_type == F_UNLCK) {
1100 if (request->fl_flags & FL_EXISTS)
1101 error = -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -04001103 }
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001104
1105 if (!new_fl) {
1106 error = -ENOLCK;
1107 goto out;
1108 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001110 locks_insert_lock_ctx(new_fl, &fl->fl_list);
Jeff Layton2e2f756f2015-02-17 17:08:23 -05001111 fl = new_fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 new_fl = NULL;
1113 }
1114 if (right) {
1115 if (left == right) {
1116 /* The new lock breaks the old one in two pieces,
1117 * so we have to use the second new lock.
1118 */
1119 left = new_fl2;
1120 new_fl2 = NULL;
1121 locks_copy_lock(left, right);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001122 locks_insert_lock_ctx(left, &fl->fl_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 }
1124 right->fl_start = request->fl_end + 1;
1125 locks_wake_up_blocks(right);
1126 }
1127 if (left) {
1128 left->fl_end = request->fl_start - 1;
1129 locks_wake_up_blocks(left);
1130 }
1131 out:
Jeff Layton6109c852015-01-16 15:05:57 -05001132 spin_unlock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 /*
1134 * Free any unused locks.
1135 */
1136 if (new_fl)
1137 locks_free_lock(new_fl);
1138 if (new_fl2)
1139 locks_free_lock(new_fl2);
Jeff Laytoned9814d2014-08-11 14:20:31 -04001140 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 return error;
1142}
1143
1144/**
1145 * posix_lock_file - Apply a POSIX-style lock to a file
1146 * @filp: The file to apply the lock to
1147 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05001148 * @conflock: Place to return a copy of the conflicting lock, if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 *
1150 * Add a POSIX style lock to a file.
1151 * We merge adjacent & overlapping locks whenever possible.
1152 * POSIX locks are sorted by owner task, then by starting address
Trond Myklebustf475ae92006-06-29 16:38:32 -04001153 *
1154 * Note that if called with an FL_EXISTS argument, the caller may determine
1155 * whether or not a lock was successfully freed by testing the return
1156 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157 */
Marc Eshel150b3932007-01-18 16:15:35 -05001158int posix_lock_file(struct file *filp, struct file_lock *fl,
Andy Adamson5842add2006-03-26 01:37:26 -08001159 struct file_lock *conflock)
1160{
Al Viro496ad9a2013-01-23 17:07:38 -05001161 return __posix_lock_file(file_inode(filp), fl, conflock);
Andy Adamson5842add2006-03-26 01:37:26 -08001162}
Marc Eshel150b3932007-01-18 16:15:35 -05001163EXPORT_SYMBOL(posix_lock_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164
1165/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001166 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1167 * @inode: inode of file to which lock request should be applied
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168 * @fl: The lock to be applied
1169 *
Jeff Layton29d01b22015-07-11 06:43:02 -04001170 * Variant of posix_lock_file_wait that does not take a filp, and so can be
1171 * used after the filp has already been torn down.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 */
Jeff Layton29d01b22015-07-11 06:43:02 -04001173int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174{
1175 int error;
1176 might_sleep ();
1177 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001178 error = __posix_lock_file(inode, fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001179 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 break;
1181 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1182 if (!error)
1183 continue;
1184
1185 locks_delete_block(fl);
1186 break;
1187 }
1188 return error;
1189}
Jeff Layton29d01b22015-07-11 06:43:02 -04001190EXPORT_SYMBOL(posix_lock_inode_wait);
1191
1192/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193 * locks_mandatory_locked - Check for an active lock
Jeff Laytond7a06982014-03-10 09:54:15 -04001194 * @file: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 *
1196 * Searches the inode's list of locks to find any POSIX locks which conflict.
1197 * This function is called from locks_verify_locked() only.
1198 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001199int locks_mandatory_locked(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001201 int ret;
Jeff Laytond7a06982014-03-10 09:54:15 -04001202 struct inode *inode = file_inode(file);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001203 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 struct file_lock *fl;
1205
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001206 ctx = inode->i_flctx;
1207 if (!ctx || list_empty_careful(&ctx->flc_posix))
1208 return 0;
1209
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 /*
1211 * Search the lock list for this inode for any POSIX locks.
1212 */
Jeff Layton6109c852015-01-16 15:05:57 -05001213 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001214 ret = 0;
1215 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001216 if (fl->fl_owner != current->files &&
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001217 fl->fl_owner != file) {
1218 ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 break;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001220 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 }
Jeff Layton6109c852015-01-16 15:05:57 -05001222 spin_unlock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001223 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224}
1225
1226/**
1227 * locks_mandatory_area - Check for a conflicting lock
1228 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1229 * for shared
1230 * @inode: the file to check
1231 * @filp: how the file was opened (if it was)
1232 * @offset: start of area to check
1233 * @count: length of area to check
1234 *
1235 * Searches the inode's list of locks to find any POSIX locks which conflict.
1236 * This function is called from rw_verify_area() and
1237 * locks_verify_truncate().
1238 */
1239int locks_mandatory_area(int read_write, struct inode *inode,
1240 struct file *filp, loff_t offset,
1241 size_t count)
1242{
1243 struct file_lock fl;
1244 int error;
Jeff Layton29723ad2014-03-10 09:54:19 -04001245 bool sleep = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246
1247 locks_init_lock(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 fl.fl_pid = current->tgid;
1249 fl.fl_file = filp;
1250 fl.fl_flags = FL_POSIX | FL_ACCESS;
1251 if (filp && !(filp->f_flags & O_NONBLOCK))
Jeff Layton29723ad2014-03-10 09:54:19 -04001252 sleep = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1254 fl.fl_start = offset;
1255 fl.fl_end = offset + count - 1;
1256
1257 for (;;) {
Jeff Layton29723ad2014-03-10 09:54:19 -04001258 if (filp) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001259 fl.fl_owner = filp;
Jeff Layton29723ad2014-03-10 09:54:19 -04001260 fl.fl_flags &= ~FL_SLEEP;
1261 error = __posix_lock_file(inode, &fl, NULL);
1262 if (!error)
1263 break;
1264 }
1265
1266 if (sleep)
1267 fl.fl_flags |= FL_SLEEP;
1268 fl.fl_owner = current->files;
Marc Eshel150b3932007-01-18 16:15:35 -05001269 error = __posix_lock_file(inode, &fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001270 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 break;
1272 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1273 if (!error) {
1274 /*
1275 * If we've been sleeping someone might have
1276 * changed the permissions behind our back.
1277 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07001278 if (__mandatory_lock(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 continue;
1280 }
1281
1282 locks_delete_block(&fl);
1283 break;
1284 }
1285
1286 return error;
1287}
1288
1289EXPORT_SYMBOL(locks_mandatory_area);
1290
J. Bruce Fields778fc542011-07-26 18:25:49 -04001291static void lease_clear_pending(struct file_lock *fl, int arg)
1292{
1293 switch (arg) {
1294 case F_UNLCK:
1295 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1296 /* fall through: */
1297 case F_RDLCK:
1298 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1299 }
1300}
1301
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302/* We already had a lease on this file; just change its type */
Jeff Layton7448cc32015-01-16 15:05:57 -05001303int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305 int error = assign_type(fl, arg);
1306
1307 if (error)
1308 return error;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001309 lease_clear_pending(fl, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 locks_wake_up_blocks(fl);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001311 if (arg == F_UNLCK) {
1312 struct file *filp = fl->fl_file;
1313
1314 f_delown(filp);
1315 filp->f_owner.signum = 0;
J. Bruce Fields96d6d592012-07-27 16:18:00 -04001316 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1317 if (fl->fl_fasync != NULL) {
1318 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1319 fl->fl_fasync = NULL;
1320 }
Jeff Laytone084c1b2015-02-16 14:32:03 -05001321 locks_delete_lock_ctx(fl, dispose);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001322 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 return 0;
1324}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325EXPORT_SYMBOL(lease_modify);
1326
J. Bruce Fields778fc542011-07-26 18:25:49 -04001327static bool past_time(unsigned long then)
1328{
1329 if (!then)
1330 /* 0 is a special value meaning "this never expires": */
1331 return false;
1332 return time_after(jiffies, then);
1333}
1334
Jeff Laytonc45198e2014-09-01 07:12:07 -04001335static void time_out_leases(struct inode *inode, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336{
Jeff Layton8634b512015-01-16 15:05:55 -05001337 struct file_lock_context *ctx = inode->i_flctx;
1338 struct file_lock *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
Jeff Layton6109c852015-01-16 15:05:57 -05001340 lockdep_assert_held(&ctx->flc_lock);
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001341
Jeff Layton8634b512015-01-16 15:05:55 -05001342 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001343 trace_time_out_leases(inode, fl);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001344 if (past_time(fl->fl_downgrade_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001345 lease_modify(fl, F_RDLCK, dispose);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001346 if (past_time(fl->fl_break_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001347 lease_modify(fl, F_UNLCK, dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 }
1349}
1350
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001351static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1352{
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001353 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1354 return false;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001355 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1356 return false;
1357 return locks_conflict(breaker, lease);
1358}
1359
Jeff Layton03d12dd2014-09-01 14:53:41 -04001360static bool
1361any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1362{
Jeff Layton8634b512015-01-16 15:05:55 -05001363 struct file_lock_context *ctx = inode->i_flctx;
Jeff Layton03d12dd2014-09-01 14:53:41 -04001364 struct file_lock *fl;
1365
Jeff Layton6109c852015-01-16 15:05:57 -05001366 lockdep_assert_held(&ctx->flc_lock);
Jeff Layton03d12dd2014-09-01 14:53:41 -04001367
Jeff Layton8634b512015-01-16 15:05:55 -05001368 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Jeff Layton03d12dd2014-09-01 14:53:41 -04001369 if (leases_conflict(fl, breaker))
1370 return true;
1371 }
1372 return false;
1373}
1374
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375/**
1376 * __break_lease - revoke all outstanding leases on file
1377 * @inode: the inode of the file to return
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001378 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1379 * break all leases
1380 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1381 * only delegations
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 *
david m. richter87250dd2007-05-09 16:10:27 -04001383 * break_lease (inlined for speed) has checked there already is at least
1384 * some kind of lock (maybe a lease) on this file. Leases are broken on
1385 * a call to open() or truncate(). This function can sleep unless you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386 * specified %O_NONBLOCK to your open().
1387 */
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001388int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389{
J. Bruce Fields778fc542011-07-26 18:25:49 -04001390 int error = 0;
Jeff Layton8634b512015-01-16 15:05:55 -05001391 struct file_lock_context *ctx = inode->i_flctx;
Yan, Zhenga9011252015-03-27 10:34:20 +08001392 struct file_lock *new_fl, *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 unsigned long break_time;
Al Viro8737c932009-12-24 06:47:55 -05001394 int want_write = (mode & O_ACCMODE) != O_RDONLY;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001395 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396
Al Viro8737c932009-12-24 06:47:55 -05001397 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001398 if (IS_ERR(new_fl))
1399 return PTR_ERR(new_fl);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001400 new_fl->fl_flags = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401
Jeff Layton8634b512015-01-16 15:05:55 -05001402 /* typically we will check that ctx is non-NULL before calling */
1403 if (!ctx) {
1404 WARN_ON_ONCE(1);
1405 return error;
1406 }
1407
Jeff Layton6109c852015-01-16 15:05:57 -05001408 spin_lock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409
Jeff Laytonc45198e2014-09-01 07:12:07 -04001410 time_out_leases(inode, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411
Jeff Layton03d12dd2014-09-01 14:53:41 -04001412 if (!any_leases_conflict(inode, new_fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001413 goto out;
1414
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415 break_time = 0;
1416 if (lease_break_time > 0) {
1417 break_time = jiffies + lease_break_time * HZ;
1418 if (break_time == 0)
1419 break_time++; /* so that 0 means no break time */
1420 }
1421
Yan, Zhenga9011252015-03-27 10:34:20 +08001422 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001423 if (!leases_conflict(fl, new_fl))
1424 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001425 if (want_write) {
1426 if (fl->fl_flags & FL_UNLOCK_PENDING)
1427 continue;
1428 fl->fl_flags |= FL_UNLOCK_PENDING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429 fl->fl_break_time = break_time;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001430 } else {
Jeff Layton8634b512015-01-16 15:05:55 -05001431 if (lease_breaking(fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001432 continue;
1433 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1434 fl->fl_downgrade_time = break_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435 }
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001436 if (fl->fl_lmops->lm_break(fl))
Jeff Laytone084c1b2015-02-16 14:32:03 -05001437 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438 }
1439
Jeff Layton8634b512015-01-16 15:05:55 -05001440 if (list_empty(&ctx->flc_lease))
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001441 goto out;
1442
Jeff Layton843c6b22014-09-01 14:27:43 -04001443 if (mode & O_NONBLOCK) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001444 trace_break_lease_noblock(inode, new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445 error = -EWOULDBLOCK;
1446 goto out;
1447 }
1448
1449restart:
Jeff Layton8634b512015-01-16 15:05:55 -05001450 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1451 break_time = fl->fl_break_time;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001452 if (break_time != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 break_time -= jiffies;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001454 if (break_time == 0)
1455 break_time++;
Jeff Layton8634b512015-01-16 15:05:55 -05001456 locks_insert_block(fl, new_fl);
Jeff Layton62af4f12014-05-09 14:13:05 -04001457 trace_break_lease_block(inode, new_fl);
Jeff Layton6109c852015-01-16 15:05:57 -05001458 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001459 locks_dispose_list(&dispose);
Matthew Wilcox4321e012008-01-14 21:28:30 -07001460 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1461 !new_fl->fl_next, break_time);
Jeff Layton6109c852015-01-16 15:05:57 -05001462 spin_lock(&ctx->flc_lock);
Jeff Layton62af4f12014-05-09 14:13:05 -04001463 trace_break_lease_unblock(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001464 locks_delete_block(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465 if (error >= 0) {
J. Bruce Fields778fc542011-07-26 18:25:49 -04001466 /*
1467 * Wait for the next conflicting lease that has not been
1468 * broken yet
1469 */
Jeff Layton03d12dd2014-09-01 14:53:41 -04001470 if (error == 0)
1471 time_out_leases(inode, &dispose);
1472 if (any_leases_conflict(inode, new_fl))
1473 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 error = 0;
1475 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476out:
Jeff Layton6109c852015-01-16 15:05:57 -05001477 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001478 locks_dispose_list(&dispose);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001479 locks_free_lock(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 return error;
1481}
1482
1483EXPORT_SYMBOL(__break_lease);
1484
1485/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001486 * lease_get_mtime - get the last modified time of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 * @inode: the inode
1488 * @time: pointer to a timespec which will contain the last modified time
1489 *
1490 * This is to force NFS clients to flush their caches for files with
1491 * exclusive leases. The justification is that if someone has an
Randy Dunlapa6b91912008-03-19 17:01:00 -07001492 * exclusive lease, then they could be modifying it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 */
1494void lease_get_mtime(struct inode *inode, struct timespec *time)
1495{
Jeff Laytonbfe86022014-08-22 10:18:44 -04001496 bool has_lease = false;
Jeff Layton8634b512015-01-16 15:05:55 -05001497 struct file_lock_context *ctx = inode->i_flctx;
1498 struct file_lock *fl;
Jeff Laytonbfe86022014-08-22 10:18:44 -04001499
Jeff Layton8634b512015-01-16 15:05:55 -05001500 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001501 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001502 if (!list_empty(&ctx->flc_lease)) {
1503 fl = list_first_entry(&ctx->flc_lease,
1504 struct file_lock, fl_list);
1505 if (fl->fl_type == F_WRLCK)
1506 has_lease = true;
1507 }
Jeff Layton6109c852015-01-16 15:05:57 -05001508 spin_unlock(&ctx->flc_lock);
Jeff Laytonbfe86022014-08-22 10:18:44 -04001509 }
1510
1511 if (has_lease)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512 *time = current_fs_time(inode->i_sb);
1513 else
1514 *time = inode->i_mtime;
1515}
1516
1517EXPORT_SYMBOL(lease_get_mtime);
1518
1519/**
1520 * fcntl_getlease - Enquire what lease is currently active
1521 * @filp: the file
1522 *
1523 * The value returned by this function will be one of
1524 * (if no lease break is pending):
1525 *
1526 * %F_RDLCK to indicate a shared lease is held.
1527 *
1528 * %F_WRLCK to indicate an exclusive lease is held.
1529 *
1530 * %F_UNLCK to indicate no lease is held.
1531 *
1532 * (if a lease break is pending):
1533 *
1534 * %F_RDLCK to indicate an exclusive lease needs to be
1535 * changed to a shared lease (or removed).
1536 *
1537 * %F_UNLCK to indicate the lease needs to be removed.
1538 *
1539 * XXX: sfr & willy disagree over whether F_INPROGRESS
1540 * should be returned to userspace.
1541 */
1542int fcntl_getlease(struct file *filp)
1543{
1544 struct file_lock *fl;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001545 struct inode *inode = file_inode(filp);
Jeff Layton8634b512015-01-16 15:05:55 -05001546 struct file_lock_context *ctx = inode->i_flctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547 int type = F_UNLCK;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001548 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549
Jeff Layton8634b512015-01-16 15:05:55 -05001550 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001551 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001552 time_out_leases(file_inode(filp), &dispose);
1553 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1554 if (fl->fl_file != filp)
1555 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001556 type = target_leasetype(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 break;
1558 }
Jeff Layton6109c852015-01-16 15:05:57 -05001559 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001560 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 return type;
1563}
1564
Jeff Layton24cbe782014-02-03 12:13:06 -05001565/**
1566 * check_conflicting_open - see if the given dentry points to a file that has
1567 * an existing open that would conflict with the
1568 * desired lease.
1569 * @dentry: dentry to check
1570 * @arg: type of lease that we're trying to acquire
1571 *
1572 * Check to see if there's an existing open fd on this file that would
1573 * conflict with the lease we're trying to set.
1574 */
1575static int
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001576check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
Jeff Layton24cbe782014-02-03 12:13:06 -05001577{
1578 int ret = 0;
1579 struct inode *inode = dentry->d_inode;
1580
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001581 if (flags & FL_LAYOUT)
1582 return 0;
1583
Jeff Layton24cbe782014-02-03 12:13:06 -05001584 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1585 return -EAGAIN;
1586
1587 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1588 (atomic_read(&inode->i_count) > 1)))
1589 ret = -EAGAIN;
1590
1591 return ret;
1592}
1593
Jeff Laytone6f5c782014-08-22 10:40:25 -04001594static int
1595generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596{
Jeff Layton8634b512015-01-16 15:05:55 -05001597 struct file_lock *fl, *my_fl = NULL, *lease;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001598 struct dentry *dentry = filp->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599 struct inode *inode = dentry->d_inode;
Jeff Layton8634b512015-01-16 15:05:55 -05001600 struct file_lock_context *ctx;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001601 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001602 int error;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001603 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604
J. Bruce Fields096657b2010-10-30 17:31:14 -04001605 lease = *flp;
Jeff Layton62af4f12014-05-09 14:13:05 -04001606 trace_generic_add_lease(inode, lease);
1607
Jeff Layton5c1c6692015-04-03 09:04:03 -04001608 /* Note that arg is never F_UNLCK here */
1609 ctx = locks_get_lock_context(inode, arg);
Jeff Layton8634b512015-01-16 15:05:55 -05001610 if (!ctx)
1611 return -ENOMEM;
1612
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001613 /*
1614 * In the delegation case we need mutual exclusion with
1615 * a number of operations that take the i_mutex. We trylock
1616 * because delegations are an optional optimization, and if
1617 * there's some chance of a conflict--we'd rather not
1618 * bother, maybe that's a sign this just isn't a good file to
1619 * hand out a delegation on.
1620 */
1621 if (is_deleg && !mutex_trylock(&inode->i_mutex))
1622 return -EAGAIN;
1623
1624 if (is_deleg && arg == F_WRLCK) {
1625 /* Write delegations are not currently supported: */
Dan Carpenter4fdb7932013-11-13 10:56:27 +03001626 mutex_unlock(&inode->i_mutex);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001627 WARN_ON_ONCE(1);
1628 return -EINVAL;
1629 }
J. Bruce Fields096657b2010-10-30 17:31:14 -04001630
Jeff Layton6109c852015-01-16 15:05:57 -05001631 spin_lock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001632 time_out_leases(inode, &dispose);
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001633 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton24cbe782014-02-03 12:13:06 -05001634 if (error)
J. Bruce Fields096657b2010-10-30 17:31:14 -04001635 goto out;
Pavel Emelyanov85c59582007-09-20 12:45:02 +04001636
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637 /*
1638 * At this point, we know that if there is an exclusive
1639 * lease on this file, then we hold it on this filp
1640 * (otherwise our open of this file would have blocked).
1641 * And if we are trying to acquire an exclusive lease,
1642 * then the file is not open by anyone (including us)
1643 * except for this filp.
1644 */
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001645 error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001646 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001647 if (fl->fl_file == filp &&
1648 fl->fl_owner == lease->fl_owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001649 my_fl = fl;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001650 continue;
1651 }
Jeff Layton8634b512015-01-16 15:05:55 -05001652
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001653 /*
1654 * No exclusive leases if someone else has a lease on
1655 * this file:
1656 */
1657 if (arg == F_WRLCK)
1658 goto out;
1659 /*
1660 * Modifying our existing lease is OK, but no getting a
1661 * new lease if someone else is opening for write:
1662 */
1663 if (fl->fl_flags & FL_UNLOCK_PENDING)
1664 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665 }
1666
Jeff Layton8634b512015-01-16 15:05:55 -05001667 if (my_fl != NULL) {
Jeff Layton0164bf02015-03-04 17:34:32 -05001668 lease = my_fl;
1669 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001670 if (error)
1671 goto out;
1672 goto out_setup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673 }
1674
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675 error = -EINVAL;
1676 if (!leases_enable)
1677 goto out;
1678
Jeff Laytone084c1b2015-02-16 14:32:03 -05001679 locks_insert_lock_ctx(lease, &ctx->flc_lease);
Jeff Layton24cbe782014-02-03 12:13:06 -05001680 /*
1681 * The check in break_lease() is lockless. It's possible for another
1682 * open to race in after we did the earlier check for a conflicting
1683 * open but before the lease was inserted. Check again for a
1684 * conflicting open and cancel the lease if there is one.
1685 *
1686 * We also add a barrier here to ensure that the insertion of the lock
1687 * precedes these checks.
1688 */
1689 smp_mb();
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001690 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton8634b512015-01-16 15:05:55 -05001691 if (error) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001692 locks_unlink_lock_ctx(lease);
Jeff Layton8634b512015-01-16 15:05:55 -05001693 goto out;
1694 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001695
1696out_setup:
1697 if (lease->fl_lmops->lm_setup)
1698 lease->fl_lmops->lm_setup(lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699out:
Jeff Layton6109c852015-01-16 15:05:57 -05001700 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001701 locks_dispose_list(&dispose);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001702 if (is_deleg)
1703 mutex_unlock(&inode->i_mutex);
Jeff Layton8634b512015-01-16 15:05:55 -05001704 if (!error && !my_fl)
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001705 *flp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 return error;
1707}
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001708
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001709static int generic_delete_lease(struct file *filp, void *owner)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001710{
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001711 int error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001712 struct file_lock *fl, *victim = NULL;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001713 struct dentry *dentry = filp->f_path.dentry;
1714 struct inode *inode = dentry->d_inode;
Jeff Layton8634b512015-01-16 15:05:55 -05001715 struct file_lock_context *ctx = inode->i_flctx;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001716 LIST_HEAD(dispose);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001717
Jeff Layton8634b512015-01-16 15:05:55 -05001718 if (!ctx) {
1719 trace_generic_delete_lease(inode, NULL);
1720 return error;
1721 }
1722
Jeff Layton6109c852015-01-16 15:05:57 -05001723 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001724 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001725 if (fl->fl_file == filp &&
1726 fl->fl_owner == owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001727 victim = fl;
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001728 break;
Jeff Layton8634b512015-01-16 15:05:55 -05001729 }
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001730 }
Jeff Laytona9b1b452015-03-14 09:45:35 -04001731 trace_generic_delete_lease(inode, victim);
Jeff Layton8634b512015-01-16 15:05:55 -05001732 if (victim)
Jeff Layton7448cc32015-01-16 15:05:57 -05001733 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05001734 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001735 locks_dispose_list(&dispose);
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001736 return error;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001737}
1738
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739/**
1740 * generic_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001741 * @filp: file pointer
1742 * @arg: type of lease to obtain
1743 * @flp: input - file_lock to use, output - file_lock inserted
1744 * @priv: private data for lm_setup (may be NULL if lm_setup
1745 * doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 *
1747 * The (input) flp->fl_lmops->lm_break function is required
1748 * by break_lease().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001750int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1751 void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753 struct dentry *dentry = filp->f_path.dentry;
1754 struct inode *inode = dentry->d_inode;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001755 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756
Eric W. Biederman8e96e3b2012-03-03 21:17:15 -08001757 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001758 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 if (!S_ISREG(inode->i_mode))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001760 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 error = security_file_lock(filp, arg);
1762 if (error)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001763 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001765 switch (arg) {
1766 case F_UNLCK:
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001767 return generic_delete_lease(filp, *priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001768 case F_RDLCK:
1769 case F_WRLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001770 if (!(*flp)->fl_lmops->lm_break) {
1771 WARN_ON_ONCE(1);
1772 return -ENOLCK;
1773 }
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001774
Jeff Laytone6f5c782014-08-22 10:40:25 -04001775 return generic_add_lease(filp, arg, flp, priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001776 default:
Dave Jones8d657eb2012-07-13 13:35:36 -04001777 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779}
Christoph Hellwig0af1a452007-07-31 00:39:22 -07001780EXPORT_SYMBOL(generic_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781
Arnd Bergmannb89f4322010-09-18 15:09:31 +02001782/**
Jeff Laytone51673a2014-08-22 18:13:28 -04001783 * vfs_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001784 * @filp: file pointer
1785 * @arg: type of lease to obtain
1786 * @lease: file_lock to use when adding a lease
1787 * @priv: private info for lm_setup when adding a lease (may be
1788 * NULL if lm_setup doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 *
Jeff Laytone51673a2014-08-22 18:13:28 -04001790 * Call this to establish a lease on the file. The "lease" argument is not
1791 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1792 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1793 * if not, this function will return -ENOLCK (and generate a scary-looking
1794 * stack trace).
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001795 *
1796 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1797 * may be NULL if the lm_setup operation doesn't require it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001799int
1800vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001802 if (filp->f_op->setlease)
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001803 return filp->f_op->setlease(filp, arg, lease, priv);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001804 else
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001805 return generic_setlease(filp, arg, lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806}
J. Bruce Fieldsa9933ce2007-06-07 17:09:49 -04001807EXPORT_SYMBOL_GPL(vfs_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001809static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001811 struct file_lock *fl;
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001812 struct fasync_struct *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813 int error;
1814
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001815 fl = lease_alloc(filp, arg);
1816 if (IS_ERR(fl))
1817 return PTR_ERR(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001818
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001819 new = fasync_alloc();
1820 if (!new) {
1821 locks_free_lock(fl);
1822 return -ENOMEM;
1823 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001824 new->fa_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001825
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001826 error = vfs_setlease(filp, arg, &fl, (void **)&new);
Jeff Layton2dfb9282014-08-11 18:14:12 -04001827 if (fl)
1828 locks_free_lock(fl);
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001829 if (new)
1830 fasync_free(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 return error;
1832}
1833
1834/**
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001835 * fcntl_setlease - sets a lease on an open file
1836 * @fd: open file descriptor
1837 * @filp: file pointer
1838 * @arg: type of lease to obtain
1839 *
1840 * Call this fcntl to establish a lease on the file.
1841 * Note that you also need to call %F_SETSIG to
1842 * receive a signal when the lease is broken.
1843 */
1844int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1845{
1846 if (arg == F_UNLCK)
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001847 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001848 return do_fcntl_add_lease(fd, filp, arg);
1849}
1850
1851/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001852 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1853 * @inode: inode of the file to apply to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 * @fl: The lock to be applied
1855 *
Jeff Layton29d01b22015-07-11 06:43:02 -04001856 * Apply a FLOCK style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 */
Jeff Layton29d01b22015-07-11 06:43:02 -04001858int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859{
1860 int error;
1861 might_sleep();
1862 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001863 error = flock_lock_inode(inode, fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001864 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 break;
1866 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1867 if (!error)
1868 continue;
1869
1870 locks_delete_block(fl);
1871 break;
1872 }
1873 return error;
1874}
Jeff Layton29d01b22015-07-11 06:43:02 -04001875EXPORT_SYMBOL(flock_lock_inode_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876
Jeff Layton29d01b22015-07-11 06:43:02 -04001877/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878 * sys_flock: - flock() system call.
1879 * @fd: the file descriptor to lock.
1880 * @cmd: the type of lock to apply.
1881 *
1882 * Apply a %FL_FLOCK style lock to an open file descriptor.
1883 * The @cmd can be one of
1884 *
1885 * %LOCK_SH -- a shared lock.
1886 *
1887 * %LOCK_EX -- an exclusive lock.
1888 *
1889 * %LOCK_UN -- remove an existing lock.
1890 *
1891 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1892 *
1893 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1894 * processes read and write access respectively.
1895 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001896SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897{
Al Viro2903ff02012-08-28 12:52:22 -04001898 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899 struct file_lock *lock;
1900 int can_sleep, unlock;
1901 int error;
1902
1903 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001904 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001905 goto out;
1906
1907 can_sleep = !(cmd & LOCK_NB);
1908 cmd &= ~LOCK_NB;
1909 unlock = (cmd == LOCK_UN);
1910
Al Viroaeb5d722008-09-02 15:28:45 -04001911 if (!unlock && !(cmd & LOCK_MAND) &&
Al Viro2903ff02012-08-28 12:52:22 -04001912 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913 goto out_putf;
1914
Jeff Layton6e129d002014-09-04 10:25:06 -04001915 lock = flock_make_lock(f.file, cmd);
1916 if (IS_ERR(lock)) {
1917 error = PTR_ERR(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918 goto out_putf;
Jeff Layton6e129d002014-09-04 10:25:06 -04001919 }
1920
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 if (can_sleep)
1922 lock->fl_flags |= FL_SLEEP;
1923
Al Viro2903ff02012-08-28 12:52:22 -04001924 error = security_file_lock(f.file, lock->fl_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925 if (error)
1926 goto out_free;
1927
Al Viro72c2d532013-09-22 16:27:52 -04001928 if (f.file->f_op->flock)
Al Viro2903ff02012-08-28 12:52:22 -04001929 error = f.file->f_op->flock(f.file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 (can_sleep) ? F_SETLKW : F_SETLK,
1931 lock);
1932 else
Al Viro2903ff02012-08-28 12:52:22 -04001933 error = flock_lock_file_wait(f.file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934
1935 out_free:
Trond Myklebust993dfa82006-03-31 02:30:55 -08001936 locks_free_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937
1938 out_putf:
Al Viro2903ff02012-08-28 12:52:22 -04001939 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940 out:
1941 return error;
1942}
1943
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001944/**
1945 * vfs_test_lock - test file byte range lock
1946 * @filp: The file to test lock for
J. Bruce Fields6924c552007-05-11 16:22:50 -04001947 * @fl: The lock to test; also used to hold result
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001948 *
1949 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1950 * setting conf->fl_type to something other than F_UNLCK.
1951 */
1952int vfs_test_lock(struct file *filp, struct file_lock *fl)
1953{
Al Viro72c2d532013-09-22 16:27:52 -04001954 if (filp->f_op->lock)
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001955 return filp->f_op->lock(filp, F_GETLK, fl);
1956 posix_test_lock(filp, fl);
1957 return 0;
1958}
1959EXPORT_SYMBOL_GPL(vfs_test_lock);
1960
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001961static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
1962{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04001963 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001964#if BITS_PER_LONG == 32
1965 /*
1966 * Make sure we can represent the posix lock via
1967 * legacy 32bit flock.
1968 */
1969 if (fl->fl_start > OFFT_OFFSET_MAX)
1970 return -EOVERFLOW;
1971 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
1972 return -EOVERFLOW;
1973#endif
1974 flock->l_start = fl->fl_start;
1975 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1976 fl->fl_end - fl->fl_start + 1;
1977 flock->l_whence = 0;
J. Bruce Fields129a84d2007-05-10 18:38:43 -04001978 flock->l_type = fl->fl_type;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001979 return 0;
1980}
1981
1982#if BITS_PER_LONG == 32
1983static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
1984{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04001985 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001986 flock->l_start = fl->fl_start;
1987 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1988 fl->fl_end - fl->fl_start + 1;
1989 flock->l_whence = 0;
1990 flock->l_type = fl->fl_type;
1991}
1992#endif
1993
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994/* Report the first existing lock that would conflict with l.
1995 * This implements the F_GETLK command of fcntl().
1996 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05001997int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05001999 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000 struct flock flock;
2001 int error;
2002
2003 error = -EFAULT;
2004 if (copy_from_user(&flock, l, sizeof(flock)))
2005 goto out;
2006 error = -EINVAL;
2007 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2008 goto out;
2009
2010 error = flock_to_posix_lock(filp, &file_lock, &flock);
2011 if (error)
2012 goto out;
2013
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002014 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002015 error = -EINVAL;
2016 if (flock.l_pid != 0)
2017 goto out;
2018
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002019 cmd = F_GETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002020 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002021 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002022 }
2023
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002024 error = vfs_test_lock(filp, &file_lock);
2025 if (error)
2026 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002028 flock.l_type = file_lock.fl_type;
2029 if (file_lock.fl_type != F_UNLCK) {
2030 error = posix_lock_to_flock(&flock, &file_lock);
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002031 if (error)
Kinglong Meef3282962014-08-22 10:18:43 -04002032 goto rel_priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002033 }
2034 error = -EFAULT;
2035 if (!copy_to_user(l, &flock, sizeof(flock)))
2036 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002037rel_priv:
2038 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039out:
2040 return error;
2041}
2042
Marc Eshel7723ec92007-01-18 15:08:55 -05002043/**
2044 * vfs_lock_file - file byte range lock
2045 * @filp: The file to apply the lock to
2046 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2047 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05002048 * @conf: Place to return a copy of the conflicting lock, if found.
2049 *
2050 * A caller that doesn't care about the conflicting lock may pass NULL
2051 * as the final argument.
2052 *
2053 * If the filesystem defines a private ->lock() method, then @conf will
2054 * be left unchanged; so a caller that cares should initialize it to
2055 * some acceptable default.
Marc Eshel2beb6612006-12-05 23:31:28 -05002056 *
2057 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2058 * locks, the ->lock() interface may return asynchronously, before the lock has
2059 * been granted or denied by the underlying filesystem, if (and only if)
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002060 * lm_grant is set. Callers expecting ->lock() to return asynchronously
Marc Eshel2beb6612006-12-05 23:31:28 -05002061 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2062 * the request is for a blocking lock. When ->lock() does return asynchronously,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002063 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
Marc Eshel2beb6612006-12-05 23:31:28 -05002064 * request completes.
2065 * If the request is for non-blocking lock the file system should return
Miklos Szeredibde74e42008-07-25 01:48:57 -07002066 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2067 * with the result. If the request timed out the callback routine will return a
Marc Eshel2beb6612006-12-05 23:31:28 -05002068 * nonzero return code and the file system should release the lock. The file
2069 * system is also responsible to keep a corresponding posix lock when it
2070 * grants a lock so the VFS can find out which locks are locally held and do
2071 * the correct lock cleanup when required.
2072 * The underlying filesystem must not drop the kernel lock or call
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002073 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
Marc Eshel2beb6612006-12-05 23:31:28 -05002074 * return code.
Marc Eshel7723ec92007-01-18 15:08:55 -05002075 */
Marc Eshel150b3932007-01-18 16:15:35 -05002076int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
Marc Eshel7723ec92007-01-18 15:08:55 -05002077{
Al Viro72c2d532013-09-22 16:27:52 -04002078 if (filp->f_op->lock)
Marc Eshel7723ec92007-01-18 15:08:55 -05002079 return filp->f_op->lock(filp, cmd, fl);
2080 else
Marc Eshel150b3932007-01-18 16:15:35 -05002081 return posix_lock_file(filp, fl, conf);
Marc Eshel7723ec92007-01-18 15:08:55 -05002082}
2083EXPORT_SYMBOL_GPL(vfs_lock_file);
2084
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002085static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2086 struct file_lock *fl)
2087{
2088 int error;
2089
2090 error = security_file_lock(filp, fl->fl_type);
2091 if (error)
2092 return error;
2093
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002094 for (;;) {
2095 error = vfs_lock_file(filp, cmd, fl, NULL);
2096 if (error != FILE_LOCK_DEFERRED)
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002097 break;
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002098 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2099 if (!error)
2100 continue;
2101
2102 locks_delete_block(fl);
2103 break;
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002104 }
2105
2106 return error;
2107}
2108
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002109/* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
2110static int
2111check_fmode_for_setlk(struct file_lock *fl)
2112{
2113 switch (fl->fl_type) {
2114 case F_RDLCK:
2115 if (!(fl->fl_file->f_mode & FMODE_READ))
2116 return -EBADF;
2117 break;
2118 case F_WRLCK:
2119 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2120 return -EBADF;
2121 }
2122 return 0;
2123}
2124
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125/* Apply the lock described by l to an open file descriptor.
2126 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2127 */
Peter Staubachc2936212005-07-27 11:45:09 -07002128int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2129 struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130{
2131 struct file_lock *file_lock = locks_alloc_lock();
2132 struct flock flock;
2133 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002134 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 int error;
2136
2137 if (file_lock == NULL)
2138 return -ENOLCK;
2139
2140 /*
2141 * This might block, so we do it before checking the inode.
2142 */
2143 error = -EFAULT;
2144 if (copy_from_user(&flock, l, sizeof(flock)))
2145 goto out;
2146
Al Viro496ad9a2013-01-23 17:07:38 -05002147 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148
2149 /* Don't allow mandatory locks on files that may be memory mapped
2150 * and shared.
2151 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002152 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002153 error = -EAGAIN;
2154 goto out;
2155 }
2156
Peter Staubachc2936212005-07-27 11:45:09 -07002157again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 error = flock_to_posix_lock(filp, file_lock, &flock);
2159 if (error)
2160 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002161
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002162 error = check_fmode_for_setlk(file_lock);
2163 if (error)
2164 goto out;
2165
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002166 /*
2167 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002168 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002169 */
2170 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002171 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002172 error = -EINVAL;
2173 if (flock.l_pid != 0)
2174 goto out;
2175
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002176 cmd = F_SETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002177 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002178 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002179 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002180 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002181 error = -EINVAL;
2182 if (flock.l_pid != 0)
2183 goto out;
2184
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002185 cmd = F_SETLKW;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002186 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002187 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002188 /* Fallthrough */
2189 case F_SETLKW:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 file_lock->fl_flags |= FL_SLEEP;
2191 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002192
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002193 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002194
Peter Staubachc2936212005-07-27 11:45:09 -07002195 /*
2196 * Attempt to detect a close/fcntl race and recover by
2197 * releasing the lock that was just acquired.
2198 */
Al Viro0b2bac22008-05-06 13:58:34 -04002199 /*
2200 * we need that spin_lock here - it prevents reordering between
Jeff Layton8116bf42015-01-21 20:44:01 -05002201 * update of i_flctx->flc_posix and check for it done in close().
Al Viro0b2bac22008-05-06 13:58:34 -04002202 * rcu_read_lock() wouldn't do.
2203 */
2204 spin_lock(&current->files->file_lock);
2205 f = fcheck(fd);
2206 spin_unlock(&current->files->file_lock);
2207 if (!error && f != filp && flock.l_type != F_UNLCK) {
Peter Staubachc2936212005-07-27 11:45:09 -07002208 flock.l_type = F_UNLCK;
2209 goto again;
2210 }
2211
2212out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 locks_free_lock(file_lock);
2214 return error;
2215}
2216
2217#if BITS_PER_LONG == 32
2218/* Report the first existing lock that would conflict with l.
2219 * This implements the F_GETLK command of fcntl().
2220 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002221int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002222{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002223 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002224 struct flock64 flock;
2225 int error;
2226
2227 error = -EFAULT;
2228 if (copy_from_user(&flock, l, sizeof(flock)))
2229 goto out;
2230 error = -EINVAL;
2231 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2232 goto out;
2233
2234 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2235 if (error)
2236 goto out;
2237
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002238 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002239 error = -EINVAL;
2240 if (flock.l_pid != 0)
2241 goto out;
2242
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002243 cmd = F_GETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002244 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002245 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002246 }
2247
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002248 error = vfs_test_lock(filp, &file_lock);
2249 if (error)
2250 goto out;
2251
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002252 flock.l_type = file_lock.fl_type;
2253 if (file_lock.fl_type != F_UNLCK)
2254 posix_lock_to_flock64(&flock, &file_lock);
2255
Linus Torvalds1da177e2005-04-16 15:20:36 -07002256 error = -EFAULT;
2257 if (!copy_to_user(l, &flock, sizeof(flock)))
2258 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002259
2260 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261out:
2262 return error;
2263}
2264
2265/* Apply the lock described by l to an open file descriptor.
2266 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2267 */
Peter Staubachc2936212005-07-27 11:45:09 -07002268int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2269 struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270{
2271 struct file_lock *file_lock = locks_alloc_lock();
2272 struct flock64 flock;
2273 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002274 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275 int error;
2276
2277 if (file_lock == NULL)
2278 return -ENOLCK;
2279
2280 /*
2281 * This might block, so we do it before checking the inode.
2282 */
2283 error = -EFAULT;
2284 if (copy_from_user(&flock, l, sizeof(flock)))
2285 goto out;
2286
Al Viro496ad9a2013-01-23 17:07:38 -05002287 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288
2289 /* Don't allow mandatory locks on files that may be memory mapped
2290 * and shared.
2291 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002292 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002293 error = -EAGAIN;
2294 goto out;
2295 }
2296
Peter Staubachc2936212005-07-27 11:45:09 -07002297again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002298 error = flock64_to_posix_lock(filp, file_lock, &flock);
2299 if (error)
2300 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002301
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002302 error = check_fmode_for_setlk(file_lock);
2303 if (error)
2304 goto out;
2305
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002306 /*
2307 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002308 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002309 */
2310 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002311 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002312 error = -EINVAL;
2313 if (flock.l_pid != 0)
2314 goto out;
2315
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002316 cmd = F_SETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002317 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002318 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002319 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002320 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002321 error = -EINVAL;
2322 if (flock.l_pid != 0)
2323 goto out;
2324
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002325 cmd = F_SETLKW64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002326 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002327 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002328 /* Fallthrough */
2329 case F_SETLKW64:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002330 file_lock->fl_flags |= FL_SLEEP;
2331 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002332
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002333 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002334
Peter Staubachc2936212005-07-27 11:45:09 -07002335 /*
2336 * Attempt to detect a close/fcntl race and recover by
2337 * releasing the lock that was just acquired.
2338 */
Al Viro0b2bac22008-05-06 13:58:34 -04002339 spin_lock(&current->files->file_lock);
2340 f = fcheck(fd);
2341 spin_unlock(&current->files->file_lock);
2342 if (!error && f != filp && flock.l_type != F_UNLCK) {
Peter Staubachc2936212005-07-27 11:45:09 -07002343 flock.l_type = F_UNLCK;
2344 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002345 }
2346
2347out:
2348 locks_free_lock(file_lock);
2349 return error;
2350}
2351#endif /* BITS_PER_LONG == 32 */
2352
2353/*
2354 * This function is called when the file is being removed
2355 * from the task's fd array. POSIX locks belonging to this task
2356 * are deleted at this time.
2357 */
2358void locks_remove_posix(struct file *filp, fl_owner_t owner)
2359{
Miklos Szerediff7b86b2006-06-23 02:05:11 -07002360 struct file_lock lock;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05002361 struct file_lock_context *ctx = file_inode(filp)->i_flctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002362
2363 /*
2364 * If there are no locks held on this file, we don't need to call
2365 * posix_lock_file(). Another process could be setting a lock on this
2366 * file at the same time, but we wouldn't remove that lock anyway.
2367 */
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05002368 if (!ctx || list_empty(&ctx->flc_posix))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 return;
2370
2371 lock.fl_type = F_UNLCK;
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07002372 lock.fl_flags = FL_POSIX | FL_CLOSE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373 lock.fl_start = 0;
2374 lock.fl_end = OFFSET_MAX;
2375 lock.fl_owner = owner;
2376 lock.fl_pid = current->tgid;
2377 lock.fl_file = filp;
2378 lock.fl_ops = NULL;
2379 lock.fl_lmops = NULL;
2380
Marc Eshel150b3932007-01-18 16:15:35 -05002381 vfs_lock_file(filp, F_SETLK, &lock, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2384 lock.fl_ops->fl_release_private(&lock);
2385}
2386
2387EXPORT_SYMBOL(locks_remove_posix);
2388
Jeff Layton3d8e5602015-01-16 15:05:58 -05002389/* The i_flctx must be valid when calling into here */
Jeff Laytondd459bb2015-01-16 15:05:54 -05002390static void
2391locks_remove_flock(struct file *filp)
2392{
2393 struct file_lock fl = {
2394 .fl_owner = filp,
2395 .fl_pid = current->tgid,
2396 .fl_file = filp,
2397 .fl_flags = FL_FLOCK,
2398 .fl_type = F_UNLCK,
2399 .fl_end = OFFSET_MAX,
2400 };
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002401 struct inode *inode = file_inode(filp);
2402 struct file_lock_context *flctx = inode->i_flctx;
Jeff Laytondd459bb2015-01-16 15:05:54 -05002403
Jeff Layton3d8e5602015-01-16 15:05:58 -05002404 if (list_empty(&flctx->flc_flock))
Jeff Laytondd459bb2015-01-16 15:05:54 -05002405 return;
2406
2407 if (filp->f_op->flock)
2408 filp->f_op->flock(filp, F_SETLKW, &fl);
2409 else
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002410 flock_lock_inode(inode, &fl);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002411
2412 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2413 fl.fl_ops->fl_release_private(&fl);
2414}
2415
Jeff Layton3d8e5602015-01-16 15:05:58 -05002416/* The i_flctx must be valid when calling into here */
Jeff Layton8634b512015-01-16 15:05:55 -05002417static void
2418locks_remove_lease(struct file *filp)
2419{
2420 struct inode *inode = file_inode(filp);
2421 struct file_lock_context *ctx = inode->i_flctx;
2422 struct file_lock *fl, *tmp;
2423 LIST_HEAD(dispose);
2424
Jeff Layton3d8e5602015-01-16 15:05:58 -05002425 if (list_empty(&ctx->flc_lease))
Jeff Layton8634b512015-01-16 15:05:55 -05002426 return;
2427
Jeff Layton6109c852015-01-16 15:05:57 -05002428 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002429 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
Jeff Laytonc4e136c2015-02-16 19:37:42 -05002430 if (filp == fl->fl_file)
2431 lease_modify(fl, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05002432 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002433 locks_dispose_list(&dispose);
2434}
2435
Linus Torvalds1da177e2005-04-16 15:20:36 -07002436/*
2437 * This function is called on the last close of an open file.
2438 */
Jeff Layton78ed8a12014-02-03 12:13:08 -05002439void locks_remove_file(struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002440{
Jeff Layton3d8e5602015-01-16 15:05:58 -05002441 if (!file_inode(filp)->i_flctx)
2442 return;
2443
Jeff Laytondd459bb2015-01-16 15:05:54 -05002444 /* remove any OFD locks */
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002445 locks_remove_posix(filp, filp);
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002446
Jeff Laytondd459bb2015-01-16 15:05:54 -05002447 /* remove flock locks */
2448 locks_remove_flock(filp);
2449
Jeff Layton8634b512015-01-16 15:05:55 -05002450 /* remove any leases */
2451 locks_remove_lease(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002452}
2453
2454/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455 * posix_unblock_lock - stop waiting for a file lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07002456 * @waiter: the lock which was waiting
2457 *
2458 * lockd needs to block waiting for locks.
2459 */
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002460int
Jeff Laytonf891a292013-06-21 08:58:09 -04002461posix_unblock_lock(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002462{
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002463 int status = 0;
2464
Jeff Layton7b2296a2013-06-21 08:58:20 -04002465 spin_lock(&blocked_lock_lock);
J. Bruce Fields5996a292006-01-03 09:55:44 +01002466 if (waiter->fl_next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002467 __locks_delete_block(waiter);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002468 else
2469 status = -ENOENT;
Jeff Layton7b2296a2013-06-21 08:58:20 -04002470 spin_unlock(&blocked_lock_lock);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002471 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002472}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002473EXPORT_SYMBOL(posix_unblock_lock);
2474
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002475/**
2476 * vfs_cancel_lock - file byte range unblock lock
2477 * @filp: The file to apply the unblock to
2478 * @fl: The lock to be unblocked
2479 *
2480 * Used by lock managers to cancel blocked requests
2481 */
2482int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2483{
Al Viro72c2d532013-09-22 16:27:52 -04002484 if (filp->f_op->lock)
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002485 return filp->f_op->lock(filp, F_CANCELLK, fl);
2486 return 0;
2487}
2488
2489EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2490
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002491#ifdef CONFIG_PROC_FS
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002492#include <linux/proc_fs.h>
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002493#include <linux/seq_file.h>
2494
Jeff Layton7012b022013-06-21 08:58:22 -04002495struct locks_iterator {
2496 int li_cpu;
2497 loff_t li_pos;
2498};
2499
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002500static void lock_get_status(struct seq_file *f, struct file_lock *fl,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002501 loff_t id, char *pfx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002502{
2503 struct inode *inode = NULL;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002504 unsigned int fl_pid;
2505
2506 if (fl->fl_nspid)
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08002507 fl_pid = pid_vnr(fl->fl_nspid);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002508 else
2509 fl_pid = fl->fl_pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002510
2511 if (fl->fl_file != NULL)
Al Viro496ad9a2013-01-23 17:07:38 -05002512 inode = file_inode(fl->fl_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513
Jerome Marchand99dc8292010-10-26 14:22:33 -07002514 seq_printf(f, "%lld:%s ", id, pfx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002515 if (IS_POSIX(fl)) {
Jeff Laytonc918d422014-02-03 12:13:09 -05002516 if (fl->fl_flags & FL_ACCESS)
Fabian Frederick5315c262014-05-09 14:13:05 -04002517 seq_puts(f, "ACCESS");
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002518 else if (IS_OFDLCK(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002519 seq_puts(f, "OFDLCK");
Jeff Laytonc918d422014-02-03 12:13:09 -05002520 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002521 seq_puts(f, "POSIX ");
Jeff Laytonc918d422014-02-03 12:13:09 -05002522
2523 seq_printf(f, " %s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002524 (inode == NULL) ? "*NOINODE*" :
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002525 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002526 } else if (IS_FLOCK(fl)) {
2527 if (fl->fl_type & LOCK_MAND) {
Fabian Frederick5315c262014-05-09 14:13:05 -04002528 seq_puts(f, "FLOCK MSNFS ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002530 seq_puts(f, "FLOCK ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002531 }
2532 } else if (IS_LEASE(fl)) {
Jeff Layton8144f1f2014-08-11 13:36:54 -04002533 if (fl->fl_flags & FL_DELEG)
2534 seq_puts(f, "DELEG ");
2535 else
2536 seq_puts(f, "LEASE ");
2537
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002538 if (lease_breaking(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002539 seq_puts(f, "BREAKING ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002540 else if (fl->fl_file)
Fabian Frederick5315c262014-05-09 14:13:05 -04002541 seq_puts(f, "ACTIVE ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002542 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002543 seq_puts(f, "BREAKER ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002544 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002545 seq_puts(f, "UNKNOWN UNKNOWN ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002546 }
2547 if (fl->fl_type & LOCK_MAND) {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002548 seq_printf(f, "%s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002549 (fl->fl_type & LOCK_READ)
2550 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2551 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2552 } else {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002553 seq_printf(f, "%s ",
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002554 (lease_breaking(fl))
Jeff Layton0ee5c6d2012-08-02 15:46:30 -04002555 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2556 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002557 }
2558 if (inode) {
Jeff Layton36488882015-04-03 09:04:04 -04002559 /* userspace relies on this representation of dev_t */
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002560 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002561 MAJOR(inode->i_sb->s_dev),
2562 MINOR(inode->i_sb->s_dev), inode->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002563 } else {
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002564 seq_printf(f, "%d <none>:0 ", fl_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002565 }
2566 if (IS_POSIX(fl)) {
2567 if (fl->fl_end == OFFSET_MAX)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002568 seq_printf(f, "%Ld EOF\n", fl->fl_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002569 else
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002570 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002571 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002572 seq_puts(f, "0 EOF\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002573 }
2574}
2575
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002576static int locks_show(struct seq_file *f, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577{
Jeff Layton7012b022013-06-21 08:58:22 -04002578 struct locks_iterator *iter = f->private;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002579 struct file_lock *fl, *bfl;
2580
Jeff Layton139ca042013-06-21 08:58:17 -04002581 fl = hlist_entry(v, struct file_lock, fl_link);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002582
Jeff Layton7012b022013-06-21 08:58:22 -04002583 lock_get_status(f, fl, iter->li_pos, "");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002584
2585 list_for_each_entry(bfl, &fl->fl_block, fl_block)
Jeff Layton7012b022013-06-21 08:58:22 -04002586 lock_get_status(f, bfl, iter->li_pos, " ->");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002587
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002588 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002589}
2590
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002591static void __show_fd_locks(struct seq_file *f,
2592 struct list_head *head, int *id,
2593 struct file *filp, struct files_struct *files)
2594{
2595 struct file_lock *fl;
2596
2597 list_for_each_entry(fl, head, fl_list) {
2598
2599 if (filp != fl->fl_file)
2600 continue;
2601 if (fl->fl_owner != files &&
2602 fl->fl_owner != filp)
2603 continue;
2604
2605 (*id)++;
2606 seq_puts(f, "lock:\t");
2607 lock_get_status(f, fl, *id, "");
2608 }
2609}
2610
2611void show_fd_locks(struct seq_file *f,
2612 struct file *filp, struct files_struct *files)
2613{
2614 struct inode *inode = file_inode(filp);
2615 struct file_lock_context *ctx;
2616 int id = 0;
2617
2618 ctx = inode->i_flctx;
2619 if (!ctx)
2620 return;
2621
2622 spin_lock(&ctx->flc_lock);
2623 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2624 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2625 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2626 spin_unlock(&ctx->flc_lock);
2627}
2628
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002629static void *locks_start(struct seq_file *f, loff_t *pos)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002630 __acquires(&blocked_lock_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631{
Jeff Layton7012b022013-06-21 08:58:22 -04002632 struct locks_iterator *iter = f->private;
Jerome Marchand99dc8292010-10-26 14:22:33 -07002633
Jeff Layton7012b022013-06-21 08:58:22 -04002634 iter->li_pos = *pos + 1;
2635 lg_global_lock(&file_lock_lglock);
Jeff Layton7b2296a2013-06-21 08:58:20 -04002636 spin_lock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002637 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002638}
2639
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002640static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2641{
Jeff Layton7012b022013-06-21 08:58:22 -04002642 struct locks_iterator *iter = f->private;
2643
2644 ++iter->li_pos;
2645 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002646}
2647
2648static void locks_stop(struct seq_file *f, void *v)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002649 __releases(&blocked_lock_lock)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002650{
Jeff Layton7b2296a2013-06-21 08:58:20 -04002651 spin_unlock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002652 lg_global_unlock(&file_lock_lglock);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002653}
2654
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002655static const struct seq_operations locks_seq_operations = {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002656 .start = locks_start,
2657 .next = locks_next,
2658 .stop = locks_stop,
2659 .show = locks_show,
2660};
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002661
2662static int locks_open(struct inode *inode, struct file *filp)
2663{
Jeff Layton7012b022013-06-21 08:58:22 -04002664 return seq_open_private(filp, &locks_seq_operations,
2665 sizeof(struct locks_iterator));
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002666}
2667
2668static const struct file_operations proc_locks_operations = {
2669 .open = locks_open,
2670 .read = seq_read,
2671 .llseek = seq_lseek,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002672 .release = seq_release_private,
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002673};
2674
2675static int __init proc_locks_init(void)
2676{
2677 proc_create("locks", 0, NULL, &proc_locks_operations);
2678 return 0;
2679}
2680module_init(proc_locks_init);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002681#endif
2682
Linus Torvalds1da177e2005-04-16 15:20:36 -07002683static int __init filelock_init(void)
2684{
Jeff Layton7012b022013-06-21 08:58:22 -04002685 int i;
2686
Jeff Layton4a075e32015-01-16 15:05:54 -05002687 flctx_cache = kmem_cache_create("file_lock_ctx",
2688 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2689
Linus Torvalds1da177e2005-04-16 15:20:36 -07002690 filelock_cache = kmem_cache_create("file_lock_cache",
Miklos Szerediee19cc42011-07-07 13:06:09 +02002691 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2692
Jeff Layton7012b022013-06-21 08:58:22 -04002693 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2694
2695 for_each_possible_cpu(i)
2696 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2697
Linus Torvalds1da177e2005-04-16 15:20:36 -07002698 return 0;
2699}
2700
2701core_initcall(filelock_init);