blob: af1ed74a657fbc93f64386bcad54d9826bc34684 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122#include <linux/security.h>
123#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124#include <linux/syscalls.h>
125#include <linux/time.h>
Dipankar Sarma4fb3a532005-09-16 19:28:13 -0700126#include <linux/rcupdate.h>
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000127#include <linux/pid_namespace.h>
Jeff Layton48f74182013-06-21 08:58:18 -0400128#include <linux/hashtable.h>
Jeff Layton7012b022013-06-21 08:58:22 -0400129#include <linux/percpu.h>
130#include <linux/lglock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
Jeff Layton62af4f12014-05-09 14:13:05 -0400132#define CREATE_TRACE_POINTS
133#include <trace/events/filelock.h>
134
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135#include <asm/uaccess.h>
136
137#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
138#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
Christoph Hellwig11afe9f2015-01-21 19:17:03 +0100139#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400140#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400142static bool lease_breaking(struct file_lock *fl)
143{
J. Bruce Fields778fc542011-07-26 18:25:49 -0400144 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
145}
146
147static int target_leasetype(struct file_lock *fl)
148{
149 if (fl->fl_flags & FL_UNLOCK_PENDING)
150 return F_UNLCK;
151 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
152 return F_RDLCK;
153 return fl->fl_type;
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400154}
155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156int leases_enable = 1;
157int lease_break_time = 45;
158
Jeff Layton1c8c6012013-06-21 08:58:15 -0400159/*
Jeff Layton7012b022013-06-21 08:58:22 -0400160 * The global file_lock_list is only used for displaying /proc/locks, so we
161 * keep a list on each CPU, with each list protected by its own spinlock via
162 * the file_lock_lglock. Note that alterations to the list also require that
Jeff Layton6109c852015-01-16 15:05:57 -0500163 * the relevant flc_lock is held.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400164 */
Jeff Layton7012b022013-06-21 08:58:22 -0400165DEFINE_STATIC_LGLOCK(file_lock_lglock);
166static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
Jeff Layton88974692013-06-21 08:58:14 -0400167
Jeff Layton1c8c6012013-06-21 08:58:15 -0400168/*
Jeff Layton48f74182013-06-21 08:58:18 -0400169 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
Jeff Layton7b2296a2013-06-21 08:58:20 -0400170 * It is protected by blocked_lock_lock.
Jeff Layton48f74182013-06-21 08:58:18 -0400171 *
172 * We hash locks by lockowner in order to optimize searching for the lock a
173 * particular lockowner is waiting on.
174 *
175 * FIXME: make this value scale via some heuristic? We generally will want more
176 * buckets when we have more lockowners holding locks, but that's a little
177 * difficult to determine without knowing what the workload will look like.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400178 */
Jeff Layton48f74182013-06-21 08:58:18 -0400179#define BLOCKED_HASH_BITS 7
180static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
Jeff Layton88974692013-06-21 08:58:14 -0400181
Jeff Layton1c8c6012013-06-21 08:58:15 -0400182/*
Jeff Layton7b2296a2013-06-21 08:58:20 -0400183 * This lock protects the blocked_hash. Generally, if you're accessing it, you
184 * want to be holding this lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400185 *
186 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
187 * pointer for file_lock structures that are acting as lock requests (in
188 * contrast to those that are acting as records of acquired locks).
189 *
190 * Note that when we acquire this lock in order to change the above fields,
Jeff Layton6109c852015-01-16 15:05:57 -0500191 * we often hold the flc_lock as well. In certain cases, when reading the fields
Jeff Layton1c8c6012013-06-21 08:58:15 -0400192 * protected by this lock, we can skip acquiring it iff we already hold the
Jeff Layton6109c852015-01-16 15:05:57 -0500193 * flc_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400194 *
195 * In particular, adding an entry to the fl_block list requires that you hold
Jeff Layton6109c852015-01-16 15:05:57 -0500196 * both the flc_lock and the blocked_lock_lock (acquired in that order).
197 * Deleting an entry from the list however only requires the file_lock_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400198 */
Jeff Layton7b2296a2013-06-21 08:58:20 -0400199static DEFINE_SPINLOCK(blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Jeff Layton4a075e32015-01-16 15:05:54 -0500201static struct kmem_cache *flctx_cache __read_mostly;
Christoph Lametere18b8902006-12-06 20:33:20 -0800202static struct kmem_cache *filelock_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
Jeff Layton4a075e32015-01-16 15:05:54 -0500204static struct file_lock_context *
Jeff Layton5c1c6692015-04-03 09:04:03 -0400205locks_get_lock_context(struct inode *inode, int type)
Jeff Layton4a075e32015-01-16 15:05:54 -0500206{
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200207 struct file_lock_context *ctx;
Jeff Layton4a075e32015-01-16 15:05:54 -0500208
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200209 /* paired with cmpxchg() below */
210 ctx = smp_load_acquire(&inode->i_flctx);
211 if (likely(ctx) || type == F_UNLCK)
Jeff Layton4a075e32015-01-16 15:05:54 -0500212 goto out;
213
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200214 ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
215 if (!ctx)
Jeff Layton4a075e32015-01-16 15:05:54 -0500216 goto out;
217
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200218 spin_lock_init(&ctx->flc_lock);
219 INIT_LIST_HEAD(&ctx->flc_flock);
220 INIT_LIST_HEAD(&ctx->flc_posix);
221 INIT_LIST_HEAD(&ctx->flc_lease);
Jeff Layton4a075e32015-01-16 15:05:54 -0500222
223 /*
224 * Assign the pointer if it's not already assigned. If it is, then
225 * free the context we just allocated.
226 */
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200227 if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
228 kmem_cache_free(flctx_cache, ctx);
229 ctx = smp_load_acquire(&inode->i_flctx);
230 }
Jeff Layton4a075e32015-01-16 15:05:54 -0500231out:
Jeff Layton18909102016-01-06 21:26:10 -0500232 trace_locks_get_lock_context(inode, type, ctx);
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200233 return ctx;
Jeff Layton4a075e32015-01-16 15:05:54 -0500234}
235
Jeff Laytone24dada2016-01-06 21:28:41 -0500236static void
237locks_dump_ctx_list(struct list_head *list, char *list_type)
238{
239 struct file_lock *fl;
240
241 list_for_each_entry(fl, list, fl_list) {
242 pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
243 }
244}
245
246static void
247locks_check_ctx_lists(struct inode *inode)
248{
249 struct file_lock_context *ctx = inode->i_flctx;
250
251 if (unlikely(!list_empty(&ctx->flc_flock) ||
252 !list_empty(&ctx->flc_posix) ||
253 !list_empty(&ctx->flc_lease))) {
254 pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
255 MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
256 inode->i_ino);
257 locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
258 locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
259 locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
260 }
261}
262
Jeff Layton4a075e32015-01-16 15:05:54 -0500263void
Jeff Laytonf27a0fe2016-01-07 15:08:51 -0500264locks_free_lock_context(struct inode *inode)
Jeff Layton4a075e32015-01-16 15:05:54 -0500265{
Jeff Laytonf27a0fe2016-01-07 15:08:51 -0500266 struct file_lock_context *ctx = inode->i_flctx;
267
Jeff Laytone24dada2016-01-06 21:28:41 -0500268 if (unlikely(ctx)) {
269 locks_check_ctx_lists(inode);
Jeff Layton4a075e32015-01-16 15:05:54 -0500270 kmem_cache_free(flctx_cache, ctx);
271 }
272}
273
Miklos Szerediee19cc42011-07-07 13:06:09 +0200274static void locks_init_lock_heads(struct file_lock *fl)
Miklos Szeredia51cb912011-07-06 12:33:55 +0200275{
Jeff Layton139ca042013-06-21 08:58:17 -0400276 INIT_HLIST_NODE(&fl->fl_link);
Jeff Layton6dee60f2015-01-16 15:05:54 -0500277 INIT_LIST_HEAD(&fl->fl_list);
Miklos Szerediee19cc42011-07-07 13:06:09 +0200278 INIT_LIST_HEAD(&fl->fl_block);
279 init_waitqueue_head(&fl->fl_wait);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200280}
281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282/* Allocate an empty lock structure. */
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200283struct file_lock *locks_alloc_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200285 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200286
287 if (fl)
Miklos Szerediee19cc42011-07-07 13:06:09 +0200288 locks_init_lock_heads(fl);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200289
290 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291}
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200292EXPORT_SYMBOL_GPL(locks_alloc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500294void locks_release_private(struct file_lock *fl)
Trond Myklebust47831f32006-03-20 13:44:05 -0500295{
296 if (fl->fl_ops) {
297 if (fl->fl_ops->fl_release_private)
298 fl->fl_ops->fl_release_private(fl);
299 fl->fl_ops = NULL;
300 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500301
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400302 if (fl->fl_lmops) {
Jeff Laytoncae80b32015-04-03 09:04:04 -0400303 if (fl->fl_lmops->lm_put_owner) {
304 fl->fl_lmops->lm_put_owner(fl->fl_owner);
305 fl->fl_owner = NULL;
306 }
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400307 fl->fl_lmops = NULL;
308 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500309}
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500310EXPORT_SYMBOL_GPL(locks_release_private);
Trond Myklebust47831f32006-03-20 13:44:05 -0500311
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312/* Free a lock which is not in use. */
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400313void locks_free_lock(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314{
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800315 BUG_ON(waitqueue_active(&fl->fl_wait));
Jeff Layton6dee60f2015-01-16 15:05:54 -0500316 BUG_ON(!list_empty(&fl->fl_list));
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800317 BUG_ON(!list_empty(&fl->fl_block));
Jeff Layton139ca042013-06-21 08:58:17 -0400318 BUG_ON(!hlist_unhashed(&fl->fl_link));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319
Trond Myklebust47831f32006-03-20 13:44:05 -0500320 locks_release_private(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 kmem_cache_free(filelock_cache, fl);
322}
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400323EXPORT_SYMBOL(locks_free_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Jeff Laytoned9814d2014-08-11 14:20:31 -0400325static void
326locks_dispose_list(struct list_head *dispose)
327{
328 struct file_lock *fl;
329
330 while (!list_empty(dispose)) {
Jeff Layton6dee60f2015-01-16 15:05:54 -0500331 fl = list_first_entry(dispose, struct file_lock, fl_list);
332 list_del_init(&fl->fl_list);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400333 locks_free_lock(fl);
334 }
335}
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337void locks_init_lock(struct file_lock *fl)
338{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200339 memset(fl, 0, sizeof(struct file_lock));
340 locks_init_lock_heads(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341}
342
343EXPORT_SYMBOL(locks_init_lock);
344
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345/*
346 * Initialize a new lock from an existing file_lock structure.
347 */
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400348void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349{
350 new->fl_owner = fl->fl_owner;
351 new->fl_pid = fl->fl_pid;
Trond Myklebust09969052006-03-20 13:44:38 -0500352 new->fl_file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 new->fl_flags = fl->fl_flags;
354 new->fl_type = fl->fl_type;
355 new->fl_start = fl->fl_start;
356 new->fl_end = fl->fl_end;
Kinglong Meef3282962014-08-22 10:18:43 -0400357 new->fl_lmops = fl->fl_lmops;
Trond Myklebust09969052006-03-20 13:44:38 -0500358 new->fl_ops = NULL;
Kinglong Meef3282962014-08-22 10:18:43 -0400359
360 if (fl->fl_lmops) {
361 if (fl->fl_lmops->lm_get_owner)
Jeff Laytoncae80b32015-04-03 09:04:04 -0400362 fl->fl_lmops->lm_get_owner(fl->fl_owner);
Kinglong Meef3282962014-08-22 10:18:43 -0400363 }
Trond Myklebust09969052006-03-20 13:44:38 -0500364}
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400365EXPORT_SYMBOL(locks_copy_conflock);
Trond Myklebust09969052006-03-20 13:44:38 -0500366
367void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
368{
Jeff Layton566709b2014-08-11 14:09:35 -0400369 /* "new" must be a freshly-initialized lock */
370 WARN_ON_ONCE(new->fl_ops);
Trond Myklebust09969052006-03-20 13:44:38 -0500371
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400372 locks_copy_conflock(new, fl);
Kinglong Meef3282962014-08-22 10:18:43 -0400373
Trond Myklebust09969052006-03-20 13:44:38 -0500374 new->fl_file = fl->fl_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 new->fl_ops = fl->fl_ops;
Trond Myklebust47831f32006-03-20 13:44:05 -0500376
Kinglong Meef3282962014-08-22 10:18:43 -0400377 if (fl->fl_ops) {
378 if (fl->fl_ops->fl_copy_lock)
379 fl->fl_ops->fl_copy_lock(new, fl);
380 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381}
382
383EXPORT_SYMBOL(locks_copy_lock);
384
385static inline int flock_translate_cmd(int cmd) {
386 if (cmd & LOCK_MAND)
387 return cmd & (LOCK_MAND | LOCK_RW);
388 switch (cmd) {
389 case LOCK_SH:
390 return F_RDLCK;
391 case LOCK_EX:
392 return F_WRLCK;
393 case LOCK_UN:
394 return F_UNLCK;
395 }
396 return -EINVAL;
397}
398
399/* Fill in a file_lock structure with an appropriate FLOCK lock. */
Jeff Layton6e129d002014-09-04 10:25:06 -0400400static struct file_lock *
401flock_make_lock(struct file *filp, unsigned int cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402{
403 struct file_lock *fl;
404 int type = flock_translate_cmd(cmd);
Jeff Layton6e129d002014-09-04 10:25:06 -0400405
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 if (type < 0)
Jeff Layton6e129d002014-09-04 10:25:06 -0400407 return ERR_PTR(type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
409 fl = locks_alloc_lock();
410 if (fl == NULL)
Jeff Layton6e129d002014-09-04 10:25:06 -0400411 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412
413 fl->fl_file = filp;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +0200414 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 fl->fl_pid = current->tgid;
416 fl->fl_flags = FL_FLOCK;
417 fl->fl_type = type;
418 fl->fl_end = OFFSET_MAX;
419
Jeff Layton6e129d002014-09-04 10:25:06 -0400420 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421}
422
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400423static int assign_type(struct file_lock *fl, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424{
425 switch (type) {
426 case F_RDLCK:
427 case F_WRLCK:
428 case F_UNLCK:
429 fl->fl_type = type;
430 break;
431 default:
432 return -EINVAL;
433 }
434 return 0;
435}
436
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500437static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
438 struct flock64 *l)
439{
440 switch (l->l_whence) {
441 case SEEK_SET:
442 fl->fl_start = 0;
443 break;
444 case SEEK_CUR:
445 fl->fl_start = filp->f_pos;
446 break;
447 case SEEK_END:
448 fl->fl_start = i_size_read(file_inode(filp));
449 break;
450 default:
451 return -EINVAL;
452 }
453 if (l->l_start > OFFSET_MAX - fl->fl_start)
454 return -EOVERFLOW;
455 fl->fl_start += l->l_start;
456 if (fl->fl_start < 0)
457 return -EINVAL;
458
459 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
460 POSIX-2001 defines it. */
461 if (l->l_len > 0) {
462 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
463 return -EOVERFLOW;
464 fl->fl_end = fl->fl_start + l->l_len - 1;
465
466 } else if (l->l_len < 0) {
467 if (fl->fl_start + l->l_len < 0)
468 return -EINVAL;
469 fl->fl_end = fl->fl_start - 1;
470 fl->fl_start += l->l_len;
471 } else
472 fl->fl_end = OFFSET_MAX;
473
474 fl->fl_owner = current->files;
475 fl->fl_pid = current->tgid;
476 fl->fl_file = filp;
477 fl->fl_flags = FL_POSIX;
478 fl->fl_ops = NULL;
479 fl->fl_lmops = NULL;
480
481 return assign_type(fl, l->l_type);
482}
483
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
485 * style lock.
486 */
487static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
488 struct flock *l)
489{
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500490 struct flock64 ll = {
491 .l_type = l->l_type,
492 .l_whence = l->l_whence,
493 .l_start = l->l_start,
494 .l_len = l->l_len,
495 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500497 return flock64_to_posix_lock(filp, fl, &ll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498}
499
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500/* default lease lock manager operations */
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400501static bool
502lease_break_callback(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503{
504 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400505 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506}
507
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400508static void
509lease_setup(struct file_lock *fl, void **priv)
510{
511 struct file *filp = fl->fl_file;
512 struct fasync_struct *fa = *priv;
513
514 /*
515 * fasync_insert_entry() returns the old entry if any. If there was no
516 * old entry, then it used "priv" and inserted it into the fasync list.
517 * Clear the pointer to indicate that it shouldn't be freed.
518 */
519 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
520 *priv = NULL;
521
522 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
523}
524
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700525static const struct lock_manager_operations lease_manager_ops = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400526 .lm_break = lease_break_callback,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400527 .lm_change = lease_modify,
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400528 .lm_setup = lease_setup,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529};
530
531/*
532 * Initialize a lease, use the default lock manager operations
533 */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400534static int lease_init(struct file *filp, long type, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 {
Trond Myklebust75dff552006-05-07 23:02:42 -0400536 if (assign_type(fl, type) != 0)
537 return -EINVAL;
538
Jeff Layton7ca76312014-09-01 19:04:48 -0400539 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 fl->fl_pid = current->tgid;
541
542 fl->fl_file = filp;
543 fl->fl_flags = FL_LEASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 fl->fl_start = 0;
545 fl->fl_end = OFFSET_MAX;
546 fl->fl_ops = NULL;
547 fl->fl_lmops = &lease_manager_ops;
548 return 0;
549}
550
551/* Allocate a file_lock initialised to this type of lease */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400552static struct file_lock *lease_alloc(struct file *filp, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553{
554 struct file_lock *fl = locks_alloc_lock();
Trond Myklebust75dff552006-05-07 23:02:42 -0400555 int error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556
557 if (fl == NULL)
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500558 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559
560 error = lease_init(filp, type, fl);
Trond Myklebust75dff552006-05-07 23:02:42 -0400561 if (error) {
562 locks_free_lock(fl);
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500563 return ERR_PTR(error);
Trond Myklebust75dff552006-05-07 23:02:42 -0400564 }
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500565 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566}
567
568/* Check if two locks overlap each other.
569 */
570static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
571{
572 return ((fl1->fl_end >= fl2->fl_start) &&
573 (fl2->fl_end >= fl1->fl_start));
574}
575
576/*
577 * Check whether two locks have the same owner.
578 */
Matt Mackall33443c42006-01-08 01:05:22 -0800579static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580{
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400581 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 return fl2->fl_lmops == fl1->fl_lmops &&
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400583 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 return fl1->fl_owner == fl2->fl_owner;
585}
586
Jeff Layton6109c852015-01-16 15:05:57 -0500587/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500588static void locks_insert_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400589{
Jeff Layton7012b022013-06-21 08:58:22 -0400590 lg_local_lock(&file_lock_lglock);
591 fl->fl_link_cpu = smp_processor_id();
592 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
593 lg_local_unlock(&file_lock_lglock);
Jeff Layton88974692013-06-21 08:58:14 -0400594}
595
Jeff Layton6109c852015-01-16 15:05:57 -0500596/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500597static void locks_delete_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400598{
Jeff Layton7012b022013-06-21 08:58:22 -0400599 /*
600 * Avoid taking lock if already unhashed. This is safe since this check
Jeff Layton6109c852015-01-16 15:05:57 -0500601 * is done while holding the flc_lock, and new insertions into the list
Jeff Layton7012b022013-06-21 08:58:22 -0400602 * also require that it be held.
603 */
604 if (hlist_unhashed(&fl->fl_link))
605 return;
606 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
Jeff Layton139ca042013-06-21 08:58:17 -0400607 hlist_del_init(&fl->fl_link);
Jeff Layton7012b022013-06-21 08:58:22 -0400608 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
Jeff Layton88974692013-06-21 08:58:14 -0400609}
610
Jeff Layton3999e492013-06-21 08:58:19 -0400611static unsigned long
612posix_owner_key(struct file_lock *fl)
613{
614 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
615 return fl->fl_lmops->lm_owner_key(fl);
616 return (unsigned long)fl->fl_owner;
617}
618
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500619static void locks_insert_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400620{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400621 lockdep_assert_held(&blocked_lock_lock);
622
Jeff Layton3999e492013-06-21 08:58:19 -0400623 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
Jeff Layton88974692013-06-21 08:58:14 -0400624}
625
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500626static void locks_delete_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400627{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400628 lockdep_assert_held(&blocked_lock_lock);
629
Jeff Layton48f74182013-06-21 08:58:18 -0400630 hash_del(&waiter->fl_link);
Jeff Layton88974692013-06-21 08:58:14 -0400631}
632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633/* Remove waiter from blocker's block list.
634 * When blocker ends up pointing to itself then the list is empty.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400635 *
Jeff Layton7b2296a2013-06-21 08:58:20 -0400636 * Must be called with blocked_lock_lock held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 */
Matt Mackall33443c42006-01-08 01:05:22 -0800638static void __locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639{
Jeff Layton88974692013-06-21 08:58:14 -0400640 locks_delete_global_blocked(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 list_del_init(&waiter->fl_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 waiter->fl_next = NULL;
643}
644
Jeff Layton1a9e64a2013-06-21 08:58:10 -0400645static void locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400647 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 __locks_delete_block(waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400649 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650}
651
652/* Insert waiter into blocker's block list.
653 * We use a circular list so that processes can be easily woken up in
654 * the order they blocked. The documentation doesn't require this but
655 * it seems like the reasonable thing to do.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400656 *
Jeff Layton6109c852015-01-16 15:05:57 -0500657 * Must be called with both the flc_lock and blocked_lock_lock held. The
658 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
659 * that the flc_lock is also held on insertions we can avoid taking the
660 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400662static void __locks_insert_block(struct file_lock *blocker,
663 struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664{
J. Bruce Fields6dc0fe82006-03-26 01:37:24 -0800665 BUG_ON(!list_empty(&waiter->fl_block));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 waiter->fl_next = blocker;
Jeff Layton88974692013-06-21 08:58:14 -0400667 list_add_tail(&waiter->fl_block, &blocker->fl_block);
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400668 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
Jeff Layton1c8c6012013-06-21 08:58:15 -0400669 locks_insert_global_blocked(waiter);
670}
671
Jeff Layton6109c852015-01-16 15:05:57 -0500672/* Must be called with flc_lock held. */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400673static void locks_insert_block(struct file_lock *blocker,
674 struct file_lock *waiter)
675{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400676 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400677 __locks_insert_block(blocker, waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400678 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679}
680
Jeff Layton1cb36012013-06-21 08:58:12 -0400681/*
682 * Wake up processes blocked waiting for blocker.
683 *
Jeff Layton6109c852015-01-16 15:05:57 -0500684 * Must be called with the inode->flc_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 */
686static void locks_wake_up_blocks(struct file_lock *blocker)
687{
Jeff Layton4e8c7652013-06-21 08:58:16 -0400688 /*
689 * Avoid taking global lock if list is empty. This is safe since new
Jeff Layton6109c852015-01-16 15:05:57 -0500690 * blocked requests are only added to the list under the flc_lock, and
691 * the flc_lock is always held here. Note that removal from the fl_block
692 * list does not require the flc_lock, so we must recheck list_empty()
Jeff Layton7b2296a2013-06-21 08:58:20 -0400693 * after acquiring the blocked_lock_lock.
Jeff Layton4e8c7652013-06-21 08:58:16 -0400694 */
695 if (list_empty(&blocker->fl_block))
696 return;
697
Jeff Layton7b2296a2013-06-21 08:58:20 -0400698 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 while (!list_empty(&blocker->fl_block)) {
Pavel Emelyanovf0c1cd02007-09-19 16:44:07 +0400700 struct file_lock *waiter;
701
702 waiter = list_first_entry(&blocker->fl_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 struct file_lock, fl_block);
704 __locks_delete_block(waiter);
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400705 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
706 waiter->fl_lmops->lm_notify(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 else
708 wake_up(&waiter->fl_wait);
709 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400710 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711}
712
Jeff Layton5263e312015-01-16 15:05:55 -0500713static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500714locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
Jeff Layton5263e312015-01-16 15:05:55 -0500715{
716 fl->fl_nspid = get_pid(task_tgid(current));
717 list_add_tail(&fl->fl_list, before);
718 locks_insert_global_locks(fl);
719}
720
Jeff Layton8634b512015-01-16 15:05:55 -0500721static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500722locks_unlink_lock_ctx(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723{
Jeff Layton88974692013-06-21 08:58:14 -0400724 locks_delete_global_locks(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500725 list_del_init(&fl->fl_list);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000726 if (fl->fl_nspid) {
727 put_pid(fl->fl_nspid);
728 fl->fl_nspid = NULL;
729 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 locks_wake_up_blocks(fl);
Jeff Layton24cbe782014-02-03 12:13:06 -0500731}
732
Jeff Layton5263e312015-01-16 15:05:55 -0500733static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500734locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
Jeff Layton5263e312015-01-16 15:05:55 -0500735{
Jeff Laytone084c1b2015-02-16 14:32:03 -0500736 locks_unlink_lock_ctx(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500737 if (dispose)
738 list_add(&fl->fl_list, dispose);
739 else
740 locks_free_lock(fl);
Jeff Layton5263e312015-01-16 15:05:55 -0500741}
742
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
744 * checks for shared/exclusive status of overlapping locks.
745 */
746static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
747{
748 if (sys_fl->fl_type == F_WRLCK)
749 return 1;
750 if (caller_fl->fl_type == F_WRLCK)
751 return 1;
752 return 0;
753}
754
755/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
756 * checking before calling the locks_conflict().
757 */
758static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
759{
760 /* POSIX locks owned by the same process do not conflict with
761 * each other.
762 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400763 if (posix_same_owner(caller_fl, sys_fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 return (0);
765
766 /* Check whether they overlap */
767 if (!locks_overlap(caller_fl, sys_fl))
768 return 0;
769
770 return (locks_conflict(caller_fl, sys_fl));
771}
772
773/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
774 * checking before calling the locks_conflict().
775 */
776static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
777{
778 /* FLOCK locks referring to the same filp do not conflict with
779 * each other.
780 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400781 if (caller_fl->fl_file == sys_fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 return (0);
783 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
784 return 0;
785
786 return (locks_conflict(caller_fl, sys_fl));
787}
788
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400789void
Marc Eshel9d6a8c52007-02-21 00:55:18 -0500790posix_test_lock(struct file *filp, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791{
792 struct file_lock *cfl;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500793 struct file_lock_context *ctx;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400794 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200796 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500797 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
J. Bruce Fields129a84d2007-05-10 18:38:43 -0400798 fl->fl_type = F_UNLCK;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500799 return;
800 }
801
Jeff Layton6109c852015-01-16 15:05:57 -0500802 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500803 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
804 if (posix_locks_conflict(fl, cfl)) {
805 locks_copy_conflock(fl, cfl);
806 if (cfl->fl_nspid)
807 fl->fl_pid = pid_vnr(cfl->fl_nspid);
808 goto out;
809 }
810 }
811 fl->fl_type = F_UNLCK;
812out:
Jeff Layton6109c852015-01-16 15:05:57 -0500813 spin_unlock(&ctx->flc_lock);
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400814 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816EXPORT_SYMBOL(posix_test_lock);
817
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400818/*
819 * Deadlock detection:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400821 * We attempt to detect deadlocks that are due purely to posix file
822 * locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400824 * We assume that a task can be waiting for at most one lock at a time.
825 * So for any acquired lock, the process holding that lock may be
826 * waiting on at most one other lock. That lock in turns may be held by
827 * someone waiting for at most one other lock. Given a requested lock
828 * caller_fl which is about to wait for a conflicting lock block_fl, we
829 * follow this chain of waiters to ensure we are not about to create a
830 * cycle.
J. Bruce Fields97855b42007-10-30 11:20:02 -0400831 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400832 * Since we do this before we ever put a process to sleep on a lock, we
833 * are ensured that there is never a cycle; that is what guarantees that
834 * the while() loop in posix_locks_deadlock() eventually completes.
835 *
836 * Note: the above assumption may not be true when handling lock
837 * requests from a broken NFS client. It may also fail in the presence
838 * of tasks (such as posix threads) sharing the same open file table.
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400839 * To handle those cases, we just bail out after a few iterations.
Jeff Layton57b65322014-02-03 12:13:09 -0500840 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400841 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
Jeff Layton57b65322014-02-03 12:13:09 -0500842 * Because the owner is not even nominally tied to a thread of
843 * execution, the deadlock detection below can't reasonably work well. Just
844 * skip it for those.
845 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400846 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
Jeff Layton57b65322014-02-03 12:13:09 -0500847 * locks that just checks for the case where two tasks are attempting to
848 * upgrade from read to write locks on the same inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 */
J. Bruce Fields97855b42007-10-30 11:20:02 -0400850
851#define MAX_DEADLK_ITERATIONS 10
852
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400853/* Find a lock that the owner of the given block_fl is blocking on. */
854static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
855{
856 struct file_lock *fl;
857
Jeff Layton3999e492013-06-21 08:58:19 -0400858 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400859 if (posix_same_owner(fl, block_fl))
860 return fl->fl_next;
861 }
862 return NULL;
863}
864
Jeff Layton7b2296a2013-06-21 08:58:20 -0400865/* Must be called with the blocked_lock_lock held! */
Adrian Bunkb0904e12006-06-23 02:05:13 -0700866static int posix_locks_deadlock(struct file_lock *caller_fl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 struct file_lock *block_fl)
868{
J. Bruce Fields97855b42007-10-30 11:20:02 -0400869 int i = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870
Daniel Wagner663d5af2015-04-03 09:04:03 -0400871 lockdep_assert_held(&blocked_lock_lock);
872
Jeff Layton57b65322014-02-03 12:13:09 -0500873 /*
874 * This deadlock detector can't reasonably detect deadlocks with
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400875 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
Jeff Layton57b65322014-02-03 12:13:09 -0500876 */
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400877 if (IS_OFDLCK(caller_fl))
Jeff Layton57b65322014-02-03 12:13:09 -0500878 return 0;
879
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400880 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
881 if (i++ > MAX_DEADLK_ITERATIONS)
882 return 0;
883 if (posix_same_owner(caller_fl, block_fl))
884 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 }
886 return 0;
887}
888
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
J. Bruce Fields02888f42007-09-12 15:45:07 -0400890 * after any leases, but before any posix locks.
Trond Myklebustf475ae92006-06-29 16:38:32 -0400891 *
892 * Note that if called with an FL_EXISTS argument, the caller may determine
893 * whether or not a lock was successfully freed by testing the return
894 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 */
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400896static int flock_lock_inode(struct inode *inode, struct file_lock *request)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897{
Trond Myklebust993dfa82006-03-31 02:30:55 -0800898 struct file_lock *new_fl = NULL;
Jeff Layton5263e312015-01-16 15:05:55 -0500899 struct file_lock *fl;
900 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 int error = 0;
Jeff Layton5263e312015-01-16 15:05:55 -0500902 bool found = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400903 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904
Jeff Layton5c1c6692015-04-03 09:04:03 -0400905 ctx = locks_get_lock_context(inode, request->fl_type);
906 if (!ctx) {
907 if (request->fl_type != F_UNLCK)
908 return -ENOMEM;
909 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
910 }
Jeff Layton5263e312015-01-16 15:05:55 -0500911
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200912 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
913 new_fl = locks_alloc_lock();
914 if (!new_fl)
915 return -ENOMEM;
916 }
917
Jeff Layton6109c852015-01-16 15:05:57 -0500918 spin_lock(&ctx->flc_lock);
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400919 if (request->fl_flags & FL_ACCESS)
920 goto find_conflict;
Pavel Emelyanov84d535a2007-09-11 16:38:13 +0400921
Jeff Layton5263e312015-01-16 15:05:55 -0500922 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400923 if (request->fl_file != fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 continue;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800925 if (request->fl_type == fl->fl_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 goto out;
Jeff Layton5263e312015-01-16 15:05:55 -0500927 found = true;
Jeff Laytone084c1b2015-02-16 14:32:03 -0500928 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 break;
930 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931
Trond Myklebustf475ae92006-06-29 16:38:32 -0400932 if (request->fl_type == F_UNLCK) {
933 if ((request->fl_flags & FL_EXISTS) && !found)
934 error = -ENOENT;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800935 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -0400936 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400938find_conflict:
Jeff Layton5263e312015-01-16 15:05:55 -0500939 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Trond Myklebust993dfa82006-03-31 02:30:55 -0800940 if (!flock_locks_conflict(request, fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 continue;
942 error = -EAGAIN;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700943 if (!(request->fl_flags & FL_SLEEP))
944 goto out;
945 error = FILE_LOCK_DEFERRED;
946 locks_insert_block(fl, request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 goto out;
948 }
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400949 if (request->fl_flags & FL_ACCESS)
950 goto out;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800951 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -0500952 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800953 new_fl = NULL;
Kirill Korotaev9cedc192006-06-14 17:59:35 +0400954 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955
956out:
Jeff Layton6109c852015-01-16 15:05:57 -0500957 spin_unlock(&ctx->flc_lock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800958 if (new_fl)
959 locks_free_lock(new_fl);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400960 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 return error;
962}
963
Jeff Laytonb4d629a2016-01-07 18:27:42 -0500964static int posix_lock_inode(struct inode *inode, struct file_lock *request,
965 struct file_lock *conflock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500967 struct file_lock *fl, *tmp;
Miklos Szeredi39005d02006-06-23 02:05:10 -0700968 struct file_lock *new_fl = NULL;
969 struct file_lock *new_fl2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 struct file_lock *left = NULL;
971 struct file_lock *right = NULL;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500972 struct file_lock_context *ctx;
Jeff Laytonb9746ef2013-06-21 08:58:13 -0400973 int error;
974 bool added = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400975 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976
Jeff Layton5c1c6692015-04-03 09:04:03 -0400977 ctx = locks_get_lock_context(inode, request->fl_type);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500978 if (!ctx)
Jeff Layton5c1c6692015-04-03 09:04:03 -0400979 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500980
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 /*
982 * We may need two file_lock structures for this operation,
983 * so we get them in advance to avoid races.
Miklos Szeredi39005d02006-06-23 02:05:10 -0700984 *
985 * In some cases we can be sure, that no new locks will be needed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 */
Miklos Szeredi39005d02006-06-23 02:05:10 -0700987 if (!(request->fl_flags & FL_ACCESS) &&
988 (request->fl_type != F_UNLCK ||
989 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
990 new_fl = locks_alloc_lock();
991 new_fl2 = locks_alloc_lock();
992 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993
Jeff Layton6109c852015-01-16 15:05:57 -0500994 spin_lock(&ctx->flc_lock);
Jeff Layton1cb36012013-06-21 08:58:12 -0400995 /*
996 * New lock request. Walk all POSIX locks and look for conflicts. If
997 * there are any, either return error or put the request on the
Jeff Layton48f74182013-06-21 08:58:18 -0400998 * blocker's list of waiters and the global blocked_hash.
Jeff Layton1cb36012013-06-21 08:58:12 -0400999 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 if (request->fl_type != F_UNLCK) {
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001001 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 if (!posix_locks_conflict(request, fl))
1003 continue;
Andy Adamson5842add2006-03-26 01:37:26 -08001004 if (conflock)
Kinglong Mee3fe0fff12014-08-22 10:18:42 -04001005 locks_copy_conflock(conflock, fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 error = -EAGAIN;
1007 if (!(request->fl_flags & FL_SLEEP))
1008 goto out;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001009 /*
1010 * Deadlock detection and insertion into the blocked
1011 * locks list must be done while holding the same lock!
1012 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 error = -EDEADLK;
Jeff Layton7b2296a2013-06-21 08:58:20 -04001014 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001015 if (likely(!posix_locks_deadlock(request, fl))) {
1016 error = FILE_LOCK_DEFERRED;
1017 __locks_insert_block(fl, request);
1018 }
Jeff Layton7b2296a2013-06-21 08:58:20 -04001019 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 goto out;
1021 }
1022 }
1023
1024 /* If we're just looking for a conflict, we're done. */
1025 error = 0;
1026 if (request->fl_flags & FL_ACCESS)
1027 goto out;
1028
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001029 /* Find the first old lock with the same owner as the new lock */
1030 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1031 if (posix_same_owner(request, fl))
1032 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 }
1034
Jeff Layton1cb36012013-06-21 08:58:12 -04001035 /* Process locks with this owner. */
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001036 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1037 if (!posix_same_owner(request, fl))
1038 break;
1039
1040 /* Detect adjacent or overlapping regions (if same lock type) */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 if (request->fl_type == fl->fl_type) {
Olaf Kirch449231d2005-08-25 16:25:35 -07001042 /* In all comparisons of start vs end, use
1043 * "start - 1" rather than "end + 1". If end
1044 * is OFFSET_MAX, end + 1 will become negative.
1045 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 if (fl->fl_end < request->fl_start - 1)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001047 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 /* If the next lock in the list has entirely bigger
1049 * addresses than the new one, insert the lock here.
1050 */
Olaf Kirch449231d2005-08-25 16:25:35 -07001051 if (fl->fl_start - 1 > request->fl_end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 break;
1053
1054 /* If we come here, the new and old lock are of the
1055 * same type and adjacent or overlapping. Make one
1056 * lock yielding from the lower start address of both
1057 * locks to the higher end address.
1058 */
1059 if (fl->fl_start > request->fl_start)
1060 fl->fl_start = request->fl_start;
1061 else
1062 request->fl_start = fl->fl_start;
1063 if (fl->fl_end < request->fl_end)
1064 fl->fl_end = request->fl_end;
1065 else
1066 request->fl_end = fl->fl_end;
1067 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001068 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 continue;
1070 }
1071 request = fl;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001072 added = true;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001073 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 /* Processing for different lock types is a bit
1075 * more complex.
1076 */
1077 if (fl->fl_end < request->fl_start)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001078 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 if (fl->fl_start > request->fl_end)
1080 break;
1081 if (request->fl_type == F_UNLCK)
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001082 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 if (fl->fl_start < request->fl_start)
1084 left = fl;
1085 /* If the next lock in the list has a higher end
1086 * address than the new one, insert the new one here.
1087 */
1088 if (fl->fl_end > request->fl_end) {
1089 right = fl;
1090 break;
1091 }
1092 if (fl->fl_start >= request->fl_start) {
1093 /* The new lock completely replaces an old
1094 * one (This may happen several times).
1095 */
1096 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001097 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 continue;
1099 }
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001100 /*
1101 * Replace the old lock with new_fl, and
1102 * remove the old one. It's safe to do the
1103 * insert here since we know that we won't be
1104 * using new_fl later, and that the lock is
1105 * just replacing an existing lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 */
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001107 error = -ENOLCK;
1108 if (!new_fl)
1109 goto out;
1110 locks_copy_lock(new_fl, request);
1111 request = new_fl;
1112 new_fl = NULL;
Jeff Laytone084c1b2015-02-16 14:32:03 -05001113 locks_insert_lock_ctx(request, &fl->fl_list);
1114 locks_delete_lock_ctx(fl, &dispose);
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001115 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 }
1117 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 }
1119
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001120 /*
Jeff Layton1cb36012013-06-21 08:58:12 -04001121 * The above code only modifies existing locks in case of merging or
1122 * replacing. If new lock(s) need to be inserted all modifications are
1123 * done below this, so it's safe yet to bail out.
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001124 */
1125 error = -ENOLCK; /* "no luck" */
1126 if (right && left == right && !new_fl2)
1127 goto out;
1128
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129 error = 0;
1130 if (!added) {
Trond Myklebustf475ae92006-06-29 16:38:32 -04001131 if (request->fl_type == F_UNLCK) {
1132 if (request->fl_flags & FL_EXISTS)
1133 error = -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -04001135 }
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001136
1137 if (!new_fl) {
1138 error = -ENOLCK;
1139 goto out;
1140 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001142 locks_insert_lock_ctx(new_fl, &fl->fl_list);
Jeff Layton2e2f756f2015-02-17 17:08:23 -05001143 fl = new_fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 new_fl = NULL;
1145 }
1146 if (right) {
1147 if (left == right) {
1148 /* The new lock breaks the old one in two pieces,
1149 * so we have to use the second new lock.
1150 */
1151 left = new_fl2;
1152 new_fl2 = NULL;
1153 locks_copy_lock(left, right);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001154 locks_insert_lock_ctx(left, &fl->fl_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 }
1156 right->fl_start = request->fl_end + 1;
1157 locks_wake_up_blocks(right);
1158 }
1159 if (left) {
1160 left->fl_end = request->fl_start - 1;
1161 locks_wake_up_blocks(left);
1162 }
1163 out:
Jeff Layton6109c852015-01-16 15:05:57 -05001164 spin_unlock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 /*
1166 * Free any unused locks.
1167 */
1168 if (new_fl)
1169 locks_free_lock(new_fl);
1170 if (new_fl2)
1171 locks_free_lock(new_fl2);
Jeff Laytoned9814d2014-08-11 14:20:31 -04001172 locks_dispose_list(&dispose);
Jeff Layton18909102016-01-06 21:26:10 -05001173 trace_posix_lock_inode(inode, request, error);
1174
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 return error;
1176}
1177
1178/**
1179 * posix_lock_file - Apply a POSIX-style lock to a file
1180 * @filp: The file to apply the lock to
1181 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05001182 * @conflock: Place to return a copy of the conflicting lock, if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183 *
1184 * Add a POSIX style lock to a file.
1185 * We merge adjacent & overlapping locks whenever possible.
1186 * POSIX locks are sorted by owner task, then by starting address
Trond Myklebustf475ae92006-06-29 16:38:32 -04001187 *
1188 * Note that if called with an FL_EXISTS argument, the caller may determine
1189 * whether or not a lock was successfully freed by testing the return
1190 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 */
Marc Eshel150b3932007-01-18 16:15:35 -05001192int posix_lock_file(struct file *filp, struct file_lock *fl,
Andy Adamson5842add2006-03-26 01:37:26 -08001193 struct file_lock *conflock)
1194{
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001195 return posix_lock_inode(file_inode(filp), fl, conflock);
Andy Adamson5842add2006-03-26 01:37:26 -08001196}
Marc Eshel150b3932007-01-18 16:15:35 -05001197EXPORT_SYMBOL(posix_lock_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198
1199/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001200 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1201 * @inode: inode of file to which lock request should be applied
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 * @fl: The lock to be applied
1203 *
Benjamin Coddington616fb382015-10-22 13:38:15 -04001204 * Apply a POSIX style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001206static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207{
1208 int error;
1209 might_sleep ();
1210 for (;;) {
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001211 error = posix_lock_inode(inode, fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001212 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 break;
1214 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1215 if (!error)
1216 continue;
1217
1218 locks_delete_block(fl);
1219 break;
1220 }
1221 return error;
1222}
Jeff Layton29d01b22015-07-11 06:43:02 -04001223
Jeff Layton9e8925b2015-11-16 09:49:34 -05001224#ifdef CONFIG_MANDATORY_FILE_LOCKING
Jeff Layton29d01b22015-07-11 06:43:02 -04001225/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 * locks_mandatory_locked - Check for an active lock
Jeff Laytond7a06982014-03-10 09:54:15 -04001227 * @file: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 *
1229 * Searches the inode's list of locks to find any POSIX locks which conflict.
1230 * This function is called from locks_verify_locked() only.
1231 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001232int locks_mandatory_locked(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001234 int ret;
Jeff Laytond7a06982014-03-10 09:54:15 -04001235 struct inode *inode = file_inode(file);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001236 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 struct file_lock *fl;
1238
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001239 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001240 if (!ctx || list_empty_careful(&ctx->flc_posix))
1241 return 0;
1242
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 /*
1244 * Search the lock list for this inode for any POSIX locks.
1245 */
Jeff Layton6109c852015-01-16 15:05:57 -05001246 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001247 ret = 0;
1248 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001249 if (fl->fl_owner != current->files &&
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001250 fl->fl_owner != file) {
1251 ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252 break;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001253 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 }
Jeff Layton6109c852015-01-16 15:05:57 -05001255 spin_unlock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001256 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257}
1258
1259/**
1260 * locks_mandatory_area - Check for a conflicting lock
Christoph Hellwigacc15572015-12-03 12:59:49 +01001261 * @inode: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 * @filp: how the file was opened (if it was)
Christoph Hellwigacc15572015-12-03 12:59:49 +01001263 * @start: first byte in the file to check
1264 * @end: lastbyte in the file to check
1265 * @type: %F_WRLCK for a write lock, else %F_RDLCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266 *
1267 * Searches the inode's list of locks to find any POSIX locks which conflict.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268 */
Christoph Hellwigacc15572015-12-03 12:59:49 +01001269int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1270 loff_t end, unsigned char type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271{
1272 struct file_lock fl;
1273 int error;
Jeff Layton29723ad2014-03-10 09:54:19 -04001274 bool sleep = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275
1276 locks_init_lock(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 fl.fl_pid = current->tgid;
1278 fl.fl_file = filp;
1279 fl.fl_flags = FL_POSIX | FL_ACCESS;
1280 if (filp && !(filp->f_flags & O_NONBLOCK))
Jeff Layton29723ad2014-03-10 09:54:19 -04001281 sleep = true;
Christoph Hellwigacc15572015-12-03 12:59:49 +01001282 fl.fl_type = type;
1283 fl.fl_start = start;
1284 fl.fl_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285
1286 for (;;) {
Jeff Layton29723ad2014-03-10 09:54:19 -04001287 if (filp) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001288 fl.fl_owner = filp;
Jeff Layton29723ad2014-03-10 09:54:19 -04001289 fl.fl_flags &= ~FL_SLEEP;
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001290 error = posix_lock_inode(inode, &fl, NULL);
Jeff Layton29723ad2014-03-10 09:54:19 -04001291 if (!error)
1292 break;
1293 }
1294
1295 if (sleep)
1296 fl.fl_flags |= FL_SLEEP;
1297 fl.fl_owner = current->files;
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001298 error = posix_lock_inode(inode, &fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001299 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 break;
1301 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1302 if (!error) {
1303 /*
1304 * If we've been sleeping someone might have
1305 * changed the permissions behind our back.
1306 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07001307 if (__mandatory_lock(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308 continue;
1309 }
1310
1311 locks_delete_block(&fl);
1312 break;
1313 }
1314
1315 return error;
1316}
1317
1318EXPORT_SYMBOL(locks_mandatory_area);
Jeff Layton9e8925b2015-11-16 09:49:34 -05001319#endif /* CONFIG_MANDATORY_FILE_LOCKING */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320
J. Bruce Fields778fc542011-07-26 18:25:49 -04001321static void lease_clear_pending(struct file_lock *fl, int arg)
1322{
1323 switch (arg) {
1324 case F_UNLCK:
1325 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1326 /* fall through: */
1327 case F_RDLCK:
1328 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1329 }
1330}
1331
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332/* We already had a lease on this file; just change its type */
Jeff Layton7448cc32015-01-16 15:05:57 -05001333int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 int error = assign_type(fl, arg);
1336
1337 if (error)
1338 return error;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001339 lease_clear_pending(fl, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 locks_wake_up_blocks(fl);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001341 if (arg == F_UNLCK) {
1342 struct file *filp = fl->fl_file;
1343
1344 f_delown(filp);
1345 filp->f_owner.signum = 0;
J. Bruce Fields96d6d592012-07-27 16:18:00 -04001346 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1347 if (fl->fl_fasync != NULL) {
1348 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1349 fl->fl_fasync = NULL;
1350 }
Jeff Laytone084c1b2015-02-16 14:32:03 -05001351 locks_delete_lock_ctx(fl, dispose);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001352 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 return 0;
1354}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355EXPORT_SYMBOL(lease_modify);
1356
J. Bruce Fields778fc542011-07-26 18:25:49 -04001357static bool past_time(unsigned long then)
1358{
1359 if (!then)
1360 /* 0 is a special value meaning "this never expires": */
1361 return false;
1362 return time_after(jiffies, then);
1363}
1364
Jeff Laytonc45198e2014-09-01 07:12:07 -04001365static void time_out_leases(struct inode *inode, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366{
Jeff Layton8634b512015-01-16 15:05:55 -05001367 struct file_lock_context *ctx = inode->i_flctx;
1368 struct file_lock *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369
Jeff Layton6109c852015-01-16 15:05:57 -05001370 lockdep_assert_held(&ctx->flc_lock);
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001371
Jeff Layton8634b512015-01-16 15:05:55 -05001372 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001373 trace_time_out_leases(inode, fl);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001374 if (past_time(fl->fl_downgrade_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001375 lease_modify(fl, F_RDLCK, dispose);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001376 if (past_time(fl->fl_break_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001377 lease_modify(fl, F_UNLCK, dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378 }
1379}
1380
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001381static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1382{
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001383 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1384 return false;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001385 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1386 return false;
1387 return locks_conflict(breaker, lease);
1388}
1389
Jeff Layton03d12dd2014-09-01 14:53:41 -04001390static bool
1391any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1392{
Jeff Layton8634b512015-01-16 15:05:55 -05001393 struct file_lock_context *ctx = inode->i_flctx;
Jeff Layton03d12dd2014-09-01 14:53:41 -04001394 struct file_lock *fl;
1395
Jeff Layton6109c852015-01-16 15:05:57 -05001396 lockdep_assert_held(&ctx->flc_lock);
Jeff Layton03d12dd2014-09-01 14:53:41 -04001397
Jeff Layton8634b512015-01-16 15:05:55 -05001398 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Jeff Layton03d12dd2014-09-01 14:53:41 -04001399 if (leases_conflict(fl, breaker))
1400 return true;
1401 }
1402 return false;
1403}
1404
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405/**
1406 * __break_lease - revoke all outstanding leases on file
1407 * @inode: the inode of the file to return
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001408 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1409 * break all leases
1410 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1411 * only delegations
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 *
david m. richter87250dd2007-05-09 16:10:27 -04001413 * break_lease (inlined for speed) has checked there already is at least
1414 * some kind of lock (maybe a lease) on this file. Leases are broken on
1415 * a call to open() or truncate(). This function can sleep unless you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416 * specified %O_NONBLOCK to your open().
1417 */
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001418int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419{
J. Bruce Fields778fc542011-07-26 18:25:49 -04001420 int error = 0;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001421 struct file_lock_context *ctx;
Yan, Zhenga9011252015-03-27 10:34:20 +08001422 struct file_lock *new_fl, *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 unsigned long break_time;
Al Viro8737c932009-12-24 06:47:55 -05001424 int want_write = (mode & O_ACCMODE) != O_RDONLY;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001425 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426
Al Viro8737c932009-12-24 06:47:55 -05001427 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001428 if (IS_ERR(new_fl))
1429 return PTR_ERR(new_fl);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001430 new_fl->fl_flags = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431
Jeff Layton8634b512015-01-16 15:05:55 -05001432 /* typically we will check that ctx is non-NULL before calling */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001433 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001434 if (!ctx) {
1435 WARN_ON_ONCE(1);
1436 return error;
1437 }
1438
Jeff Layton6109c852015-01-16 15:05:57 -05001439 spin_lock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440
Jeff Laytonc45198e2014-09-01 07:12:07 -04001441 time_out_leases(inode, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442
Jeff Layton03d12dd2014-09-01 14:53:41 -04001443 if (!any_leases_conflict(inode, new_fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001444 goto out;
1445
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 break_time = 0;
1447 if (lease_break_time > 0) {
1448 break_time = jiffies + lease_break_time * HZ;
1449 if (break_time == 0)
1450 break_time++; /* so that 0 means no break time */
1451 }
1452
Yan, Zhenga9011252015-03-27 10:34:20 +08001453 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001454 if (!leases_conflict(fl, new_fl))
1455 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001456 if (want_write) {
1457 if (fl->fl_flags & FL_UNLOCK_PENDING)
1458 continue;
1459 fl->fl_flags |= FL_UNLOCK_PENDING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 fl->fl_break_time = break_time;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001461 } else {
Jeff Layton8634b512015-01-16 15:05:55 -05001462 if (lease_breaking(fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001463 continue;
1464 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1465 fl->fl_downgrade_time = break_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466 }
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001467 if (fl->fl_lmops->lm_break(fl))
Jeff Laytone084c1b2015-02-16 14:32:03 -05001468 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 }
1470
Jeff Layton8634b512015-01-16 15:05:55 -05001471 if (list_empty(&ctx->flc_lease))
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001472 goto out;
1473
Jeff Layton843c6b22014-09-01 14:27:43 -04001474 if (mode & O_NONBLOCK) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001475 trace_break_lease_noblock(inode, new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 error = -EWOULDBLOCK;
1477 goto out;
1478 }
1479
1480restart:
Jeff Layton8634b512015-01-16 15:05:55 -05001481 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1482 break_time = fl->fl_break_time;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001483 if (break_time != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 break_time -= jiffies;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001485 if (break_time == 0)
1486 break_time++;
Jeff Layton8634b512015-01-16 15:05:55 -05001487 locks_insert_block(fl, new_fl);
Jeff Layton62af4f12014-05-09 14:13:05 -04001488 trace_break_lease_block(inode, new_fl);
Jeff Layton6109c852015-01-16 15:05:57 -05001489 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001490 locks_dispose_list(&dispose);
Matthew Wilcox4321e012008-01-14 21:28:30 -07001491 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1492 !new_fl->fl_next, break_time);
Jeff Layton6109c852015-01-16 15:05:57 -05001493 spin_lock(&ctx->flc_lock);
Jeff Layton62af4f12014-05-09 14:13:05 -04001494 trace_break_lease_unblock(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001495 locks_delete_block(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 if (error >= 0) {
J. Bruce Fields778fc542011-07-26 18:25:49 -04001497 /*
1498 * Wait for the next conflicting lease that has not been
1499 * broken yet
1500 */
Jeff Layton03d12dd2014-09-01 14:53:41 -04001501 if (error == 0)
1502 time_out_leases(inode, &dispose);
1503 if (any_leases_conflict(inode, new_fl))
1504 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 error = 0;
1506 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507out:
Jeff Layton6109c852015-01-16 15:05:57 -05001508 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001509 locks_dispose_list(&dispose);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001510 locks_free_lock(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001511 return error;
1512}
1513
1514EXPORT_SYMBOL(__break_lease);
1515
1516/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001517 * lease_get_mtime - get the last modified time of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 * @inode: the inode
1519 * @time: pointer to a timespec which will contain the last modified time
1520 *
1521 * This is to force NFS clients to flush their caches for files with
1522 * exclusive leases. The justification is that if someone has an
Randy Dunlapa6b91912008-03-19 17:01:00 -07001523 * exclusive lease, then they could be modifying it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524 */
1525void lease_get_mtime(struct inode *inode, struct timespec *time)
1526{
Jeff Laytonbfe86022014-08-22 10:18:44 -04001527 bool has_lease = false;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001528 struct file_lock_context *ctx;
Jeff Layton8634b512015-01-16 15:05:55 -05001529 struct file_lock *fl;
Jeff Laytonbfe86022014-08-22 10:18:44 -04001530
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001531 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001532 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001533 spin_lock(&ctx->flc_lock);
Geliang Tang8ace5df2015-11-18 21:40:33 +08001534 fl = list_first_entry_or_null(&ctx->flc_lease,
1535 struct file_lock, fl_list);
1536 if (fl && (fl->fl_type == F_WRLCK))
1537 has_lease = true;
Jeff Layton6109c852015-01-16 15:05:57 -05001538 spin_unlock(&ctx->flc_lock);
Jeff Laytonbfe86022014-08-22 10:18:44 -04001539 }
1540
1541 if (has_lease)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542 *time = current_fs_time(inode->i_sb);
1543 else
1544 *time = inode->i_mtime;
1545}
1546
1547EXPORT_SYMBOL(lease_get_mtime);
1548
1549/**
1550 * fcntl_getlease - Enquire what lease is currently active
1551 * @filp: the file
1552 *
1553 * The value returned by this function will be one of
1554 * (if no lease break is pending):
1555 *
1556 * %F_RDLCK to indicate a shared lease is held.
1557 *
1558 * %F_WRLCK to indicate an exclusive lease is held.
1559 *
1560 * %F_UNLCK to indicate no lease is held.
1561 *
1562 * (if a lease break is pending):
1563 *
1564 * %F_RDLCK to indicate an exclusive lease needs to be
1565 * changed to a shared lease (or removed).
1566 *
1567 * %F_UNLCK to indicate the lease needs to be removed.
1568 *
1569 * XXX: sfr & willy disagree over whether F_INPROGRESS
1570 * should be returned to userspace.
1571 */
1572int fcntl_getlease(struct file *filp)
1573{
1574 struct file_lock *fl;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001575 struct inode *inode = file_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001576 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577 int type = F_UNLCK;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001578 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001580 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001581 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001582 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001583 time_out_leases(file_inode(filp), &dispose);
1584 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1585 if (fl->fl_file != filp)
1586 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001587 type = target_leasetype(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588 break;
1589 }
Jeff Layton6109c852015-01-16 15:05:57 -05001590 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001591 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001593 return type;
1594}
1595
Jeff Layton24cbe782014-02-03 12:13:06 -05001596/**
1597 * check_conflicting_open - see if the given dentry points to a file that has
1598 * an existing open that would conflict with the
1599 * desired lease.
1600 * @dentry: dentry to check
1601 * @arg: type of lease that we're trying to acquire
Randy Dunlap7fadc592015-08-09 18:43:17 -07001602 * @flags: current lock flags
Jeff Layton24cbe782014-02-03 12:13:06 -05001603 *
1604 * Check to see if there's an existing open fd on this file that would
1605 * conflict with the lease we're trying to set.
1606 */
1607static int
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001608check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
Jeff Layton24cbe782014-02-03 12:13:06 -05001609{
1610 int ret = 0;
1611 struct inode *inode = dentry->d_inode;
1612
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001613 if (flags & FL_LAYOUT)
1614 return 0;
1615
Jeff Layton24cbe782014-02-03 12:13:06 -05001616 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1617 return -EAGAIN;
1618
1619 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1620 (atomic_read(&inode->i_count) > 1)))
1621 ret = -EAGAIN;
1622
1623 return ret;
1624}
1625
Jeff Laytone6f5c782014-08-22 10:40:25 -04001626static int
1627generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628{
Jeff Layton8634b512015-01-16 15:05:55 -05001629 struct file_lock *fl, *my_fl = NULL, *lease;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001630 struct dentry *dentry = filp->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 struct inode *inode = dentry->d_inode;
Jeff Layton8634b512015-01-16 15:05:55 -05001632 struct file_lock_context *ctx;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001633 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001634 int error;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001635 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001636
J. Bruce Fields096657b2010-10-30 17:31:14 -04001637 lease = *flp;
Jeff Layton62af4f12014-05-09 14:13:05 -04001638 trace_generic_add_lease(inode, lease);
1639
Jeff Layton5c1c6692015-04-03 09:04:03 -04001640 /* Note that arg is never F_UNLCK here */
1641 ctx = locks_get_lock_context(inode, arg);
Jeff Layton8634b512015-01-16 15:05:55 -05001642 if (!ctx)
1643 return -ENOMEM;
1644
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001645 /*
1646 * In the delegation case we need mutual exclusion with
1647 * a number of operations that take the i_mutex. We trylock
1648 * because delegations are an optional optimization, and if
1649 * there's some chance of a conflict--we'd rather not
1650 * bother, maybe that's a sign this just isn't a good file to
1651 * hand out a delegation on.
1652 */
1653 if (is_deleg && !mutex_trylock(&inode->i_mutex))
1654 return -EAGAIN;
1655
1656 if (is_deleg && arg == F_WRLCK) {
1657 /* Write delegations are not currently supported: */
Dan Carpenter4fdb7932013-11-13 10:56:27 +03001658 mutex_unlock(&inode->i_mutex);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001659 WARN_ON_ONCE(1);
1660 return -EINVAL;
1661 }
J. Bruce Fields096657b2010-10-30 17:31:14 -04001662
Jeff Layton6109c852015-01-16 15:05:57 -05001663 spin_lock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001664 time_out_leases(inode, &dispose);
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001665 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton24cbe782014-02-03 12:13:06 -05001666 if (error)
J. Bruce Fields096657b2010-10-30 17:31:14 -04001667 goto out;
Pavel Emelyanov85c59582007-09-20 12:45:02 +04001668
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 /*
1670 * At this point, we know that if there is an exclusive
1671 * lease on this file, then we hold it on this filp
1672 * (otherwise our open of this file would have blocked).
1673 * And if we are trying to acquire an exclusive lease,
1674 * then the file is not open by anyone (including us)
1675 * except for this filp.
1676 */
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001677 error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001678 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001679 if (fl->fl_file == filp &&
1680 fl->fl_owner == lease->fl_owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001681 my_fl = fl;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001682 continue;
1683 }
Jeff Layton8634b512015-01-16 15:05:55 -05001684
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001685 /*
1686 * No exclusive leases if someone else has a lease on
1687 * this file:
1688 */
1689 if (arg == F_WRLCK)
1690 goto out;
1691 /*
1692 * Modifying our existing lease is OK, but no getting a
1693 * new lease if someone else is opening for write:
1694 */
1695 if (fl->fl_flags & FL_UNLOCK_PENDING)
1696 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 }
1698
Jeff Layton8634b512015-01-16 15:05:55 -05001699 if (my_fl != NULL) {
Jeff Layton0164bf02015-03-04 17:34:32 -05001700 lease = my_fl;
1701 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001702 if (error)
1703 goto out;
1704 goto out_setup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705 }
1706
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 error = -EINVAL;
1708 if (!leases_enable)
1709 goto out;
1710
Jeff Laytone084c1b2015-02-16 14:32:03 -05001711 locks_insert_lock_ctx(lease, &ctx->flc_lease);
Jeff Layton24cbe782014-02-03 12:13:06 -05001712 /*
1713 * The check in break_lease() is lockless. It's possible for another
1714 * open to race in after we did the earlier check for a conflicting
1715 * open but before the lease was inserted. Check again for a
1716 * conflicting open and cancel the lease if there is one.
1717 *
1718 * We also add a barrier here to ensure that the insertion of the lock
1719 * precedes these checks.
1720 */
1721 smp_mb();
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001722 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton8634b512015-01-16 15:05:55 -05001723 if (error) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001724 locks_unlink_lock_ctx(lease);
Jeff Layton8634b512015-01-16 15:05:55 -05001725 goto out;
1726 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001727
1728out_setup:
1729 if (lease->fl_lmops->lm_setup)
1730 lease->fl_lmops->lm_setup(lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731out:
Jeff Layton6109c852015-01-16 15:05:57 -05001732 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001733 locks_dispose_list(&dispose);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001734 if (is_deleg)
1735 mutex_unlock(&inode->i_mutex);
Jeff Layton8634b512015-01-16 15:05:55 -05001736 if (!error && !my_fl)
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001737 *flp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738 return error;
1739}
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001740
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001741static int generic_delete_lease(struct file *filp, void *owner)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001742{
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001743 int error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001744 struct file_lock *fl, *victim = NULL;
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04001745 struct inode *inode = file_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001746 struct file_lock_context *ctx;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001747 LIST_HEAD(dispose);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001748
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001749 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001750 if (!ctx) {
1751 trace_generic_delete_lease(inode, NULL);
1752 return error;
1753 }
1754
Jeff Layton6109c852015-01-16 15:05:57 -05001755 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001756 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001757 if (fl->fl_file == filp &&
1758 fl->fl_owner == owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001759 victim = fl;
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001760 break;
Jeff Layton8634b512015-01-16 15:05:55 -05001761 }
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001762 }
Jeff Laytona9b1b452015-03-14 09:45:35 -04001763 trace_generic_delete_lease(inode, victim);
Jeff Layton8634b512015-01-16 15:05:55 -05001764 if (victim)
Jeff Layton7448cc32015-01-16 15:05:57 -05001765 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05001766 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001767 locks_dispose_list(&dispose);
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001768 return error;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001769}
1770
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771/**
1772 * generic_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001773 * @filp: file pointer
1774 * @arg: type of lease to obtain
1775 * @flp: input - file_lock to use, output - file_lock inserted
1776 * @priv: private data for lm_setup (may be NULL if lm_setup
1777 * doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 *
1779 * The (input) flp->fl_lmops->lm_break function is required
1780 * by break_lease().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001782int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1783 void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784{
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04001785 struct inode *inode = file_inode(filp);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001786 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787
Eric W. Biederman8e96e3b2012-03-03 21:17:15 -08001788 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001789 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 if (!S_ISREG(inode->i_mode))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001791 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001792 error = security_file_lock(filp, arg);
1793 if (error)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001794 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001796 switch (arg) {
1797 case F_UNLCK:
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001798 return generic_delete_lease(filp, *priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001799 case F_RDLCK:
1800 case F_WRLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001801 if (!(*flp)->fl_lmops->lm_break) {
1802 WARN_ON_ONCE(1);
1803 return -ENOLCK;
1804 }
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001805
Jeff Laytone6f5c782014-08-22 10:40:25 -04001806 return generic_add_lease(filp, arg, flp, priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001807 default:
Dave Jones8d657eb2012-07-13 13:35:36 -04001808 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810}
Christoph Hellwig0af1a452007-07-31 00:39:22 -07001811EXPORT_SYMBOL(generic_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001812
Arnd Bergmannb89f4322010-09-18 15:09:31 +02001813/**
Jeff Laytone51673a2014-08-22 18:13:28 -04001814 * vfs_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001815 * @filp: file pointer
1816 * @arg: type of lease to obtain
1817 * @lease: file_lock to use when adding a lease
1818 * @priv: private info for lm_setup when adding a lease (may be
1819 * NULL if lm_setup doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 *
Jeff Laytone51673a2014-08-22 18:13:28 -04001821 * Call this to establish a lease on the file. The "lease" argument is not
1822 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1823 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1824 * if not, this function will return -ENOLCK (and generate a scary-looking
1825 * stack trace).
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001826 *
1827 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1828 * may be NULL if the lm_setup operation doesn't require it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001830int
1831vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001833 if (filp->f_op->setlease)
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001834 return filp->f_op->setlease(filp, arg, lease, priv);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001835 else
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001836 return generic_setlease(filp, arg, lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837}
J. Bruce Fieldsa9933ce2007-06-07 17:09:49 -04001838EXPORT_SYMBOL_GPL(vfs_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001839
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001840static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001842 struct file_lock *fl;
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001843 struct fasync_struct *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 int error;
1845
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001846 fl = lease_alloc(filp, arg);
1847 if (IS_ERR(fl))
1848 return PTR_ERR(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001850 new = fasync_alloc();
1851 if (!new) {
1852 locks_free_lock(fl);
1853 return -ENOMEM;
1854 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001855 new->fa_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001857 error = vfs_setlease(filp, arg, &fl, (void **)&new);
Jeff Layton2dfb9282014-08-11 18:14:12 -04001858 if (fl)
1859 locks_free_lock(fl);
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001860 if (new)
1861 fasync_free(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862 return error;
1863}
1864
1865/**
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001866 * fcntl_setlease - sets a lease on an open file
1867 * @fd: open file descriptor
1868 * @filp: file pointer
1869 * @arg: type of lease to obtain
1870 *
1871 * Call this fcntl to establish a lease on the file.
1872 * Note that you also need to call %F_SETSIG to
1873 * receive a signal when the lease is broken.
1874 */
1875int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1876{
1877 if (arg == F_UNLCK)
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001878 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001879 return do_fcntl_add_lease(fd, filp, arg);
1880}
1881
1882/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001883 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1884 * @inode: inode of the file to apply to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 * @fl: The lock to be applied
1886 *
Jeff Layton29d01b22015-07-11 06:43:02 -04001887 * Apply a FLOCK style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001889static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890{
1891 int error;
1892 might_sleep();
1893 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001894 error = flock_lock_inode(inode, fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001895 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 break;
1897 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1898 if (!error)
1899 continue;
1900
1901 locks_delete_block(fl);
1902 break;
1903 }
1904 return error;
1905}
1906
Jeff Layton29d01b22015-07-11 06:43:02 -04001907/**
Benjamin Coddingtone55c34a2015-10-22 13:38:13 -04001908 * locks_lock_inode_wait - Apply a lock to an inode
1909 * @inode: inode of the file to apply to
1910 * @fl: The lock to be applied
1911 *
1912 * Apply a POSIX or FLOCK style lock request to an inode.
1913 */
1914int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1915{
1916 int res = 0;
1917 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1918 case FL_POSIX:
1919 res = posix_lock_inode_wait(inode, fl);
1920 break;
1921 case FL_FLOCK:
1922 res = flock_lock_inode_wait(inode, fl);
1923 break;
1924 default:
1925 BUG();
1926 }
1927 return res;
1928}
1929EXPORT_SYMBOL(locks_lock_inode_wait);
1930
1931/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932 * sys_flock: - flock() system call.
1933 * @fd: the file descriptor to lock.
1934 * @cmd: the type of lock to apply.
1935 *
1936 * Apply a %FL_FLOCK style lock to an open file descriptor.
1937 * The @cmd can be one of
1938 *
1939 * %LOCK_SH -- a shared lock.
1940 *
1941 * %LOCK_EX -- an exclusive lock.
1942 *
1943 * %LOCK_UN -- remove an existing lock.
1944 *
1945 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1946 *
1947 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1948 * processes read and write access respectively.
1949 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001950SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951{
Al Viro2903ff02012-08-28 12:52:22 -04001952 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 struct file_lock *lock;
1954 int can_sleep, unlock;
1955 int error;
1956
1957 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001958 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959 goto out;
1960
1961 can_sleep = !(cmd & LOCK_NB);
1962 cmd &= ~LOCK_NB;
1963 unlock = (cmd == LOCK_UN);
1964
Al Viroaeb5d722008-09-02 15:28:45 -04001965 if (!unlock && !(cmd & LOCK_MAND) &&
Al Viro2903ff02012-08-28 12:52:22 -04001966 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 goto out_putf;
1968
Jeff Layton6e129d002014-09-04 10:25:06 -04001969 lock = flock_make_lock(f.file, cmd);
1970 if (IS_ERR(lock)) {
1971 error = PTR_ERR(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 goto out_putf;
Jeff Layton6e129d002014-09-04 10:25:06 -04001973 }
1974
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 if (can_sleep)
1976 lock->fl_flags |= FL_SLEEP;
1977
Al Viro2903ff02012-08-28 12:52:22 -04001978 error = security_file_lock(f.file, lock->fl_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979 if (error)
1980 goto out_free;
1981
Al Viro72c2d532013-09-22 16:27:52 -04001982 if (f.file->f_op->flock)
Al Viro2903ff02012-08-28 12:52:22 -04001983 error = f.file->f_op->flock(f.file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984 (can_sleep) ? F_SETLKW : F_SETLK,
1985 lock);
1986 else
Benjamin Coddington4f656362015-10-22 13:38:14 -04001987 error = locks_lock_file_wait(f.file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988
1989 out_free:
Trond Myklebust993dfa82006-03-31 02:30:55 -08001990 locks_free_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991
1992 out_putf:
Al Viro2903ff02012-08-28 12:52:22 -04001993 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 out:
1995 return error;
1996}
1997
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001998/**
1999 * vfs_test_lock - test file byte range lock
2000 * @filp: The file to test lock for
J. Bruce Fields6924c552007-05-11 16:22:50 -04002001 * @fl: The lock to test; also used to hold result
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002002 *
2003 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2004 * setting conf->fl_type to something other than F_UNLCK.
2005 */
2006int vfs_test_lock(struct file *filp, struct file_lock *fl)
2007{
Al Viro72c2d532013-09-22 16:27:52 -04002008 if (filp->f_op->lock)
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002009 return filp->f_op->lock(filp, F_GETLK, fl);
2010 posix_test_lock(filp, fl);
2011 return 0;
2012}
2013EXPORT_SYMBOL_GPL(vfs_test_lock);
2014
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002015static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2016{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002017 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002018#if BITS_PER_LONG == 32
2019 /*
2020 * Make sure we can represent the posix lock via
2021 * legacy 32bit flock.
2022 */
2023 if (fl->fl_start > OFFT_OFFSET_MAX)
2024 return -EOVERFLOW;
2025 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2026 return -EOVERFLOW;
2027#endif
2028 flock->l_start = fl->fl_start;
2029 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2030 fl->fl_end - fl->fl_start + 1;
2031 flock->l_whence = 0;
J. Bruce Fields129a84d2007-05-10 18:38:43 -04002032 flock->l_type = fl->fl_type;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002033 return 0;
2034}
2035
2036#if BITS_PER_LONG == 32
2037static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2038{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002039 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002040 flock->l_start = fl->fl_start;
2041 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2042 fl->fl_end - fl->fl_start + 1;
2043 flock->l_whence = 0;
2044 flock->l_type = fl->fl_type;
2045}
2046#endif
2047
Linus Torvalds1da177e2005-04-16 15:20:36 -07002048/* Report the first existing lock that would conflict with l.
2049 * This implements the F_GETLK command of fcntl().
2050 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002051int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002053 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002054 struct flock flock;
2055 int error;
2056
2057 error = -EFAULT;
2058 if (copy_from_user(&flock, l, sizeof(flock)))
2059 goto out;
2060 error = -EINVAL;
2061 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2062 goto out;
2063
2064 error = flock_to_posix_lock(filp, &file_lock, &flock);
2065 if (error)
2066 goto out;
2067
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002068 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002069 error = -EINVAL;
2070 if (flock.l_pid != 0)
2071 goto out;
2072
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002073 cmd = F_GETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002074 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002075 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002076 }
2077
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002078 error = vfs_test_lock(filp, &file_lock);
2079 if (error)
2080 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002082 flock.l_type = file_lock.fl_type;
2083 if (file_lock.fl_type != F_UNLCK) {
2084 error = posix_lock_to_flock(&flock, &file_lock);
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002085 if (error)
Kinglong Meef3282962014-08-22 10:18:43 -04002086 goto rel_priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002087 }
2088 error = -EFAULT;
2089 if (!copy_to_user(l, &flock, sizeof(flock)))
2090 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002091rel_priv:
2092 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002093out:
2094 return error;
2095}
2096
Marc Eshel7723ec92007-01-18 15:08:55 -05002097/**
2098 * vfs_lock_file - file byte range lock
2099 * @filp: The file to apply the lock to
2100 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2101 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05002102 * @conf: Place to return a copy of the conflicting lock, if found.
2103 *
2104 * A caller that doesn't care about the conflicting lock may pass NULL
2105 * as the final argument.
2106 *
2107 * If the filesystem defines a private ->lock() method, then @conf will
2108 * be left unchanged; so a caller that cares should initialize it to
2109 * some acceptable default.
Marc Eshel2beb6612006-12-05 23:31:28 -05002110 *
2111 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2112 * locks, the ->lock() interface may return asynchronously, before the lock has
2113 * been granted or denied by the underlying filesystem, if (and only if)
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002114 * lm_grant is set. Callers expecting ->lock() to return asynchronously
Marc Eshel2beb6612006-12-05 23:31:28 -05002115 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2116 * the request is for a blocking lock. When ->lock() does return asynchronously,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002117 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
Marc Eshel2beb6612006-12-05 23:31:28 -05002118 * request completes.
2119 * If the request is for non-blocking lock the file system should return
Miklos Szeredibde74e42008-07-25 01:48:57 -07002120 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2121 * with the result. If the request timed out the callback routine will return a
Marc Eshel2beb6612006-12-05 23:31:28 -05002122 * nonzero return code and the file system should release the lock. The file
2123 * system is also responsible to keep a corresponding posix lock when it
2124 * grants a lock so the VFS can find out which locks are locally held and do
2125 * the correct lock cleanup when required.
2126 * The underlying filesystem must not drop the kernel lock or call
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002127 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
Marc Eshel2beb6612006-12-05 23:31:28 -05002128 * return code.
Marc Eshel7723ec92007-01-18 15:08:55 -05002129 */
Marc Eshel150b3932007-01-18 16:15:35 -05002130int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
Marc Eshel7723ec92007-01-18 15:08:55 -05002131{
Al Viro72c2d532013-09-22 16:27:52 -04002132 if (filp->f_op->lock)
Marc Eshel7723ec92007-01-18 15:08:55 -05002133 return filp->f_op->lock(filp, cmd, fl);
2134 else
Marc Eshel150b3932007-01-18 16:15:35 -05002135 return posix_lock_file(filp, fl, conf);
Marc Eshel7723ec92007-01-18 15:08:55 -05002136}
2137EXPORT_SYMBOL_GPL(vfs_lock_file);
2138
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002139static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2140 struct file_lock *fl)
2141{
2142 int error;
2143
2144 error = security_file_lock(filp, fl->fl_type);
2145 if (error)
2146 return error;
2147
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002148 for (;;) {
2149 error = vfs_lock_file(filp, cmd, fl, NULL);
2150 if (error != FILE_LOCK_DEFERRED)
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002151 break;
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002152 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2153 if (!error)
2154 continue;
2155
2156 locks_delete_block(fl);
2157 break;
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002158 }
2159
2160 return error;
2161}
2162
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04002163/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002164static int
2165check_fmode_for_setlk(struct file_lock *fl)
2166{
2167 switch (fl->fl_type) {
2168 case F_RDLCK:
2169 if (!(fl->fl_file->f_mode & FMODE_READ))
2170 return -EBADF;
2171 break;
2172 case F_WRLCK:
2173 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2174 return -EBADF;
2175 }
2176 return 0;
2177}
2178
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179/* Apply the lock described by l to an open file descriptor.
2180 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2181 */
Peter Staubachc2936212005-07-27 11:45:09 -07002182int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2183 struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184{
2185 struct file_lock *file_lock = locks_alloc_lock();
2186 struct flock flock;
2187 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002188 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002189 int error;
2190
2191 if (file_lock == NULL)
2192 return -ENOLCK;
2193
Jeff Layton18909102016-01-06 21:26:10 -05002194 inode = file_inode(filp);
2195
Linus Torvalds1da177e2005-04-16 15:20:36 -07002196 /*
2197 * This might block, so we do it before checking the inode.
2198 */
2199 error = -EFAULT;
2200 if (copy_from_user(&flock, l, sizeof(flock)))
2201 goto out;
2202
Linus Torvalds1da177e2005-04-16 15:20:36 -07002203 /* Don't allow mandatory locks on files that may be memory mapped
2204 * and shared.
2205 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002206 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 error = -EAGAIN;
2208 goto out;
2209 }
2210
2211 error = flock_to_posix_lock(filp, file_lock, &flock);
2212 if (error)
2213 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002214
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002215 error = check_fmode_for_setlk(file_lock);
2216 if (error)
2217 goto out;
2218
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002219 /*
2220 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002221 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002222 */
2223 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002224 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002225 error = -EINVAL;
2226 if (flock.l_pid != 0)
2227 goto out;
2228
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002229 cmd = F_SETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002230 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002231 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002232 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002233 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002234 error = -EINVAL;
2235 if (flock.l_pid != 0)
2236 goto out;
2237
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002238 cmd = F_SETLKW;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002239 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002240 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002241 /* Fallthrough */
2242 case F_SETLKW:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243 file_lock->fl_flags |= FL_SLEEP;
2244 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002245
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002246 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002247
Peter Staubachc2936212005-07-27 11:45:09 -07002248 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002249 * Attempt to detect a close/fcntl race and recover by releasing the
2250 * lock that was just acquired. There is no need to do that when we're
2251 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002252 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002253 if (!error && file_lock->fl_type != F_UNLCK &&
2254 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002255 /*
2256 * We need that spin_lock here - it prevents reordering between
2257 * update of i_flctx->flc_posix and check for it done in
2258 * close(). rcu_read_lock() wouldn't do.
2259 */
2260 spin_lock(&current->files->file_lock);
2261 f = fcheck(fd);
2262 spin_unlock(&current->files->file_lock);
2263 if (f != filp) {
2264 file_lock->fl_type = F_UNLCK;
2265 error = do_lock_file_wait(filp, cmd, file_lock);
2266 WARN_ON_ONCE(error);
2267 error = -EBADF;
2268 }
Peter Staubachc2936212005-07-27 11:45:09 -07002269 }
Peter Staubachc2936212005-07-27 11:45:09 -07002270out:
Jeff Layton18909102016-01-06 21:26:10 -05002271 trace_fcntl_setlk(inode, file_lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272 locks_free_lock(file_lock);
2273 return error;
2274}
2275
2276#if BITS_PER_LONG == 32
2277/* Report the first existing lock that would conflict with l.
2278 * This implements the F_GETLK command of fcntl().
2279 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002280int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002282 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283 struct flock64 flock;
2284 int error;
2285
2286 error = -EFAULT;
2287 if (copy_from_user(&flock, l, sizeof(flock)))
2288 goto out;
2289 error = -EINVAL;
2290 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2291 goto out;
2292
2293 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2294 if (error)
2295 goto out;
2296
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002297 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002298 error = -EINVAL;
2299 if (flock.l_pid != 0)
2300 goto out;
2301
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002302 cmd = F_GETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002303 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002304 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002305 }
2306
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002307 error = vfs_test_lock(filp, &file_lock);
2308 if (error)
2309 goto out;
2310
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002311 flock.l_type = file_lock.fl_type;
2312 if (file_lock.fl_type != F_UNLCK)
2313 posix_lock_to_flock64(&flock, &file_lock);
2314
Linus Torvalds1da177e2005-04-16 15:20:36 -07002315 error = -EFAULT;
2316 if (!copy_to_user(l, &flock, sizeof(flock)))
2317 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002318
2319 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320out:
2321 return error;
2322}
2323
2324/* Apply the lock described by l to an open file descriptor.
2325 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2326 */
Peter Staubachc2936212005-07-27 11:45:09 -07002327int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2328 struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002329{
2330 struct file_lock *file_lock = locks_alloc_lock();
2331 struct flock64 flock;
2332 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002333 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002334 int error;
2335
2336 if (file_lock == NULL)
2337 return -ENOLCK;
2338
2339 /*
2340 * This might block, so we do it before checking the inode.
2341 */
2342 error = -EFAULT;
2343 if (copy_from_user(&flock, l, sizeof(flock)))
2344 goto out;
2345
Al Viro496ad9a2013-01-23 17:07:38 -05002346 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002347
2348 /* Don't allow mandatory locks on files that may be memory mapped
2349 * and shared.
2350 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002351 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352 error = -EAGAIN;
2353 goto out;
2354 }
2355
2356 error = flock64_to_posix_lock(filp, file_lock, &flock);
2357 if (error)
2358 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002359
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002360 error = check_fmode_for_setlk(file_lock);
2361 if (error)
2362 goto out;
2363
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002364 /*
2365 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002366 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002367 */
2368 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002369 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002370 error = -EINVAL;
2371 if (flock.l_pid != 0)
2372 goto out;
2373
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002374 cmd = F_SETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002375 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002376 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002377 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002378 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002379 error = -EINVAL;
2380 if (flock.l_pid != 0)
2381 goto out;
2382
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002383 cmd = F_SETLKW64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002384 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002385 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002386 /* Fallthrough */
2387 case F_SETLKW64:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388 file_lock->fl_flags |= FL_SLEEP;
2389 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002390
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002391 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392
Peter Staubachc2936212005-07-27 11:45:09 -07002393 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002394 * Attempt to detect a close/fcntl race and recover by releasing the
2395 * lock that was just acquired. There is no need to do that when we're
2396 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002397 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002398 if (!error && file_lock->fl_type != F_UNLCK &&
2399 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002400 /*
2401 * We need that spin_lock here - it prevents reordering between
2402 * update of i_flctx->flc_posix and check for it done in
2403 * close(). rcu_read_lock() wouldn't do.
2404 */
2405 spin_lock(&current->files->file_lock);
2406 f = fcheck(fd);
2407 spin_unlock(&current->files->file_lock);
2408 if (f != filp) {
2409 file_lock->fl_type = F_UNLCK;
2410 error = do_lock_file_wait(filp, cmd, file_lock);
2411 WARN_ON_ONCE(error);
2412 error = -EBADF;
2413 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002414 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002415out:
2416 locks_free_lock(file_lock);
2417 return error;
2418}
2419#endif /* BITS_PER_LONG == 32 */
2420
2421/*
2422 * This function is called when the file is being removed
2423 * from the task's fd array. POSIX locks belonging to this task
2424 * are deleted at this time.
2425 */
2426void locks_remove_posix(struct file *filp, fl_owner_t owner)
2427{
Jeff Layton18909102016-01-06 21:26:10 -05002428 int error;
Miklos Szerediff7b86b2006-06-23 02:05:11 -07002429 struct file_lock lock;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002430 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431
2432 /*
2433 * If there are no locks held on this file, we don't need to call
2434 * posix_lock_file(). Another process could be setting a lock on this
2435 * file at the same time, but we wouldn't remove that lock anyway.
2436 */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002437 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05002438 if (!ctx || list_empty(&ctx->flc_posix))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002439 return;
2440
2441 lock.fl_type = F_UNLCK;
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07002442 lock.fl_flags = FL_POSIX | FL_CLOSE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002443 lock.fl_start = 0;
2444 lock.fl_end = OFFSET_MAX;
2445 lock.fl_owner = owner;
2446 lock.fl_pid = current->tgid;
2447 lock.fl_file = filp;
2448 lock.fl_ops = NULL;
2449 lock.fl_lmops = NULL;
2450
Jeff Layton18909102016-01-06 21:26:10 -05002451 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002452
Linus Torvalds1da177e2005-04-16 15:20:36 -07002453 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2454 lock.fl_ops->fl_release_private(&lock);
Jeff Layton18909102016-01-06 21:26:10 -05002455 trace_locks_remove_posix(file_inode(filp), &lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002456}
2457
2458EXPORT_SYMBOL(locks_remove_posix);
2459
Jeff Layton3d8e5602015-01-16 15:05:58 -05002460/* The i_flctx must be valid when calling into here */
Jeff Laytondd459bb2015-01-16 15:05:54 -05002461static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002462locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
Jeff Laytondd459bb2015-01-16 15:05:54 -05002463{
2464 struct file_lock fl = {
2465 .fl_owner = filp,
2466 .fl_pid = current->tgid,
2467 .fl_file = filp,
2468 .fl_flags = FL_FLOCK,
2469 .fl_type = F_UNLCK,
2470 .fl_end = OFFSET_MAX,
2471 };
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002472 struct inode *inode = file_inode(filp);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002473
Jeff Layton3d8e5602015-01-16 15:05:58 -05002474 if (list_empty(&flctx->flc_flock))
Jeff Laytondd459bb2015-01-16 15:05:54 -05002475 return;
2476
2477 if (filp->f_op->flock)
2478 filp->f_op->flock(filp, F_SETLKW, &fl);
2479 else
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002480 flock_lock_inode(inode, &fl);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002481
2482 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2483 fl.fl_ops->fl_release_private(&fl);
2484}
2485
Jeff Layton3d8e5602015-01-16 15:05:58 -05002486/* The i_flctx must be valid when calling into here */
Jeff Layton8634b512015-01-16 15:05:55 -05002487static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002488locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
Jeff Layton8634b512015-01-16 15:05:55 -05002489{
Jeff Layton8634b512015-01-16 15:05:55 -05002490 struct file_lock *fl, *tmp;
2491 LIST_HEAD(dispose);
2492
Jeff Layton3d8e5602015-01-16 15:05:58 -05002493 if (list_empty(&ctx->flc_lease))
Jeff Layton8634b512015-01-16 15:05:55 -05002494 return;
2495
Jeff Layton6109c852015-01-16 15:05:57 -05002496 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002497 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
Jeff Laytonc4e136c2015-02-16 19:37:42 -05002498 if (filp == fl->fl_file)
2499 lease_modify(fl, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05002500 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002501 locks_dispose_list(&dispose);
2502}
2503
Linus Torvalds1da177e2005-04-16 15:20:36 -07002504/*
2505 * This function is called on the last close of an open file.
2506 */
Jeff Layton78ed8a12014-02-03 12:13:08 -05002507void locks_remove_file(struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002508{
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002509 struct file_lock_context *ctx;
2510
2511 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
2512 if (!ctx)
Jeff Layton3d8e5602015-01-16 15:05:58 -05002513 return;
2514
Jeff Laytondd459bb2015-01-16 15:05:54 -05002515 /* remove any OFD locks */
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002516 locks_remove_posix(filp, filp);
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002517
Jeff Laytondd459bb2015-01-16 15:05:54 -05002518 /* remove flock locks */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002519 locks_remove_flock(filp, ctx);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002520
Jeff Layton8634b512015-01-16 15:05:55 -05002521 /* remove any leases */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002522 locks_remove_lease(filp, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002523}
2524
2525/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002526 * posix_unblock_lock - stop waiting for a file lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07002527 * @waiter: the lock which was waiting
2528 *
2529 * lockd needs to block waiting for locks.
2530 */
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002531int
Jeff Laytonf891a292013-06-21 08:58:09 -04002532posix_unblock_lock(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002533{
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002534 int status = 0;
2535
Jeff Layton7b2296a2013-06-21 08:58:20 -04002536 spin_lock(&blocked_lock_lock);
J. Bruce Fields5996a292006-01-03 09:55:44 +01002537 if (waiter->fl_next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002538 __locks_delete_block(waiter);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002539 else
2540 status = -ENOENT;
Jeff Layton7b2296a2013-06-21 08:58:20 -04002541 spin_unlock(&blocked_lock_lock);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002542 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002543}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002544EXPORT_SYMBOL(posix_unblock_lock);
2545
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002546/**
2547 * vfs_cancel_lock - file byte range unblock lock
2548 * @filp: The file to apply the unblock to
2549 * @fl: The lock to be unblocked
2550 *
2551 * Used by lock managers to cancel blocked requests
2552 */
2553int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2554{
Al Viro72c2d532013-09-22 16:27:52 -04002555 if (filp->f_op->lock)
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002556 return filp->f_op->lock(filp, F_CANCELLK, fl);
2557 return 0;
2558}
2559
2560EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2561
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002562#ifdef CONFIG_PROC_FS
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002563#include <linux/proc_fs.h>
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002564#include <linux/seq_file.h>
2565
Jeff Layton7012b022013-06-21 08:58:22 -04002566struct locks_iterator {
2567 int li_cpu;
2568 loff_t li_pos;
2569};
2570
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002571static void lock_get_status(struct seq_file *f, struct file_lock *fl,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002572 loff_t id, char *pfx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002573{
2574 struct inode *inode = NULL;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002575 unsigned int fl_pid;
2576
2577 if (fl->fl_nspid)
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08002578 fl_pid = pid_vnr(fl->fl_nspid);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002579 else
2580 fl_pid = fl->fl_pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002581
2582 if (fl->fl_file != NULL)
Al Viro496ad9a2013-01-23 17:07:38 -05002583 inode = file_inode(fl->fl_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002584
Jerome Marchand99dc8292010-10-26 14:22:33 -07002585 seq_printf(f, "%lld:%s ", id, pfx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002586 if (IS_POSIX(fl)) {
Jeff Laytonc918d422014-02-03 12:13:09 -05002587 if (fl->fl_flags & FL_ACCESS)
Fabian Frederick5315c262014-05-09 14:13:05 -04002588 seq_puts(f, "ACCESS");
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002589 else if (IS_OFDLCK(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002590 seq_puts(f, "OFDLCK");
Jeff Laytonc918d422014-02-03 12:13:09 -05002591 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002592 seq_puts(f, "POSIX ");
Jeff Laytonc918d422014-02-03 12:13:09 -05002593
2594 seq_printf(f, " %s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002595 (inode == NULL) ? "*NOINODE*" :
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002596 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002597 } else if (IS_FLOCK(fl)) {
2598 if (fl->fl_type & LOCK_MAND) {
Fabian Frederick5315c262014-05-09 14:13:05 -04002599 seq_puts(f, "FLOCK MSNFS ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002600 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002601 seq_puts(f, "FLOCK ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002602 }
2603 } else if (IS_LEASE(fl)) {
Jeff Layton8144f1f2014-08-11 13:36:54 -04002604 if (fl->fl_flags & FL_DELEG)
2605 seq_puts(f, "DELEG ");
2606 else
2607 seq_puts(f, "LEASE ");
2608
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002609 if (lease_breaking(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002610 seq_puts(f, "BREAKING ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002611 else if (fl->fl_file)
Fabian Frederick5315c262014-05-09 14:13:05 -04002612 seq_puts(f, "ACTIVE ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002613 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002614 seq_puts(f, "BREAKER ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002615 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002616 seq_puts(f, "UNKNOWN UNKNOWN ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002617 }
2618 if (fl->fl_type & LOCK_MAND) {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002619 seq_printf(f, "%s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002620 (fl->fl_type & LOCK_READ)
2621 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2622 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2623 } else {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002624 seq_printf(f, "%s ",
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002625 (lease_breaking(fl))
Jeff Layton0ee5c6d2012-08-02 15:46:30 -04002626 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2627 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002628 }
2629 if (inode) {
Jeff Layton36488882015-04-03 09:04:04 -04002630 /* userspace relies on this representation of dev_t */
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002631 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002632 MAJOR(inode->i_sb->s_dev),
2633 MINOR(inode->i_sb->s_dev), inode->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002634 } else {
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002635 seq_printf(f, "%d <none>:0 ", fl_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002636 }
2637 if (IS_POSIX(fl)) {
2638 if (fl->fl_end == OFFSET_MAX)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002639 seq_printf(f, "%Ld EOF\n", fl->fl_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002640 else
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002641 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002642 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002643 seq_puts(f, "0 EOF\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002644 }
2645}
2646
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002647static int locks_show(struct seq_file *f, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002648{
Jeff Layton7012b022013-06-21 08:58:22 -04002649 struct locks_iterator *iter = f->private;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002650 struct file_lock *fl, *bfl;
2651
Jeff Layton139ca042013-06-21 08:58:17 -04002652 fl = hlist_entry(v, struct file_lock, fl_link);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002653
Jeff Layton7012b022013-06-21 08:58:22 -04002654 lock_get_status(f, fl, iter->li_pos, "");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002655
2656 list_for_each_entry(bfl, &fl->fl_block, fl_block)
Jeff Layton7012b022013-06-21 08:58:22 -04002657 lock_get_status(f, bfl, iter->li_pos, " ->");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002658
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002659 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002660}
2661
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002662static void __show_fd_locks(struct seq_file *f,
2663 struct list_head *head, int *id,
2664 struct file *filp, struct files_struct *files)
2665{
2666 struct file_lock *fl;
2667
2668 list_for_each_entry(fl, head, fl_list) {
2669
2670 if (filp != fl->fl_file)
2671 continue;
2672 if (fl->fl_owner != files &&
2673 fl->fl_owner != filp)
2674 continue;
2675
2676 (*id)++;
2677 seq_puts(f, "lock:\t");
2678 lock_get_status(f, fl, *id, "");
2679 }
2680}
2681
2682void show_fd_locks(struct seq_file *f,
2683 struct file *filp, struct files_struct *files)
2684{
2685 struct inode *inode = file_inode(filp);
2686 struct file_lock_context *ctx;
2687 int id = 0;
2688
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002689 ctx = smp_load_acquire(&inode->i_flctx);
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002690 if (!ctx)
2691 return;
2692
2693 spin_lock(&ctx->flc_lock);
2694 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2695 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2696 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2697 spin_unlock(&ctx->flc_lock);
2698}
2699
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002700static void *locks_start(struct seq_file *f, loff_t *pos)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002701 __acquires(&blocked_lock_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002702{
Jeff Layton7012b022013-06-21 08:58:22 -04002703 struct locks_iterator *iter = f->private;
Jerome Marchand99dc8292010-10-26 14:22:33 -07002704
Jeff Layton7012b022013-06-21 08:58:22 -04002705 iter->li_pos = *pos + 1;
2706 lg_global_lock(&file_lock_lglock);
Jeff Layton7b2296a2013-06-21 08:58:20 -04002707 spin_lock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002708 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002709}
2710
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002711static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2712{
Jeff Layton7012b022013-06-21 08:58:22 -04002713 struct locks_iterator *iter = f->private;
2714
2715 ++iter->li_pos;
2716 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002717}
2718
2719static void locks_stop(struct seq_file *f, void *v)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002720 __releases(&blocked_lock_lock)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002721{
Jeff Layton7b2296a2013-06-21 08:58:20 -04002722 spin_unlock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002723 lg_global_unlock(&file_lock_lglock);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002724}
2725
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002726static const struct seq_operations locks_seq_operations = {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002727 .start = locks_start,
2728 .next = locks_next,
2729 .stop = locks_stop,
2730 .show = locks_show,
2731};
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002732
2733static int locks_open(struct inode *inode, struct file *filp)
2734{
Jeff Layton7012b022013-06-21 08:58:22 -04002735 return seq_open_private(filp, &locks_seq_operations,
2736 sizeof(struct locks_iterator));
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002737}
2738
2739static const struct file_operations proc_locks_operations = {
2740 .open = locks_open,
2741 .read = seq_read,
2742 .llseek = seq_lseek,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002743 .release = seq_release_private,
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002744};
2745
2746static int __init proc_locks_init(void)
2747{
2748 proc_create("locks", 0, NULL, &proc_locks_operations);
2749 return 0;
2750}
Paul Gortmaker91899222015-12-17 14:11:03 -05002751fs_initcall(proc_locks_init);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002752#endif
2753
Linus Torvalds1da177e2005-04-16 15:20:36 -07002754static int __init filelock_init(void)
2755{
Jeff Layton7012b022013-06-21 08:58:22 -04002756 int i;
2757
Jeff Layton4a075e32015-01-16 15:05:54 -05002758 flctx_cache = kmem_cache_create("file_lock_ctx",
2759 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2760
Linus Torvalds1da177e2005-04-16 15:20:36 -07002761 filelock_cache = kmem_cache_create("file_lock_cache",
Miklos Szerediee19cc42011-07-07 13:06:09 +02002762 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2763
Jeff Layton7012b022013-06-21 08:58:22 -04002764 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2765
2766 for_each_possible_cpu(i)
2767 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2768
Linus Torvalds1da177e2005-04-16 15:20:36 -07002769 return 0;
2770}
2771
2772core_initcall(filelock_init);