blob: ca272eb63c309980629b67ed90cd384b3389734b [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
Marc Eshel150b3932007-01-18 16:15:35 -0500964static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500966 struct file_lock *fl, *tmp;
Miklos Szeredi39005d02006-06-23 02:05:10 -0700967 struct file_lock *new_fl = NULL;
968 struct file_lock *new_fl2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 struct file_lock *left = NULL;
970 struct file_lock *right = NULL;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500971 struct file_lock_context *ctx;
Jeff Laytonb9746ef2013-06-21 08:58:13 -0400972 int error;
973 bool added = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400974 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
Jeff Layton5c1c6692015-04-03 09:04:03 -0400976 ctx = locks_get_lock_context(inode, request->fl_type);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500977 if (!ctx)
Jeff Layton5c1c6692015-04-03 09:04:03 -0400978 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500979
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 /*
981 * We may need two file_lock structures for this operation,
982 * so we get them in advance to avoid races.
Miklos Szeredi39005d02006-06-23 02:05:10 -0700983 *
984 * In some cases we can be sure, that no new locks will be needed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 */
Miklos Szeredi39005d02006-06-23 02:05:10 -0700986 if (!(request->fl_flags & FL_ACCESS) &&
987 (request->fl_type != F_UNLCK ||
988 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
989 new_fl = locks_alloc_lock();
990 new_fl2 = locks_alloc_lock();
991 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
Jeff Layton6109c852015-01-16 15:05:57 -0500993 spin_lock(&ctx->flc_lock);
Jeff Layton1cb36012013-06-21 08:58:12 -0400994 /*
995 * New lock request. Walk all POSIX locks and look for conflicts. If
996 * there are any, either return error or put the request on the
Jeff Layton48f74182013-06-21 08:58:18 -0400997 * blocker's list of waiters and the global blocked_hash.
Jeff Layton1cb36012013-06-21 08:58:12 -0400998 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 if (request->fl_type != F_UNLCK) {
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001000 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 if (!posix_locks_conflict(request, fl))
1002 continue;
Andy Adamson5842add2006-03-26 01:37:26 -08001003 if (conflock)
Kinglong Mee3fe0fff12014-08-22 10:18:42 -04001004 locks_copy_conflock(conflock, fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 error = -EAGAIN;
1006 if (!(request->fl_flags & FL_SLEEP))
1007 goto out;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001008 /*
1009 * Deadlock detection and insertion into the blocked
1010 * locks list must be done while holding the same lock!
1011 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 error = -EDEADLK;
Jeff Layton7b2296a2013-06-21 08:58:20 -04001013 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001014 if (likely(!posix_locks_deadlock(request, fl))) {
1015 error = FILE_LOCK_DEFERRED;
1016 __locks_insert_block(fl, request);
1017 }
Jeff Layton7b2296a2013-06-21 08:58:20 -04001018 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 goto out;
1020 }
1021 }
1022
1023 /* If we're just looking for a conflict, we're done. */
1024 error = 0;
1025 if (request->fl_flags & FL_ACCESS)
1026 goto out;
1027
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001028 /* Find the first old lock with the same owner as the new lock */
1029 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1030 if (posix_same_owner(request, fl))
1031 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 }
1033
Jeff Layton1cb36012013-06-21 08:58:12 -04001034 /* Process locks with this owner. */
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001035 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1036 if (!posix_same_owner(request, fl))
1037 break;
1038
1039 /* Detect adjacent or overlapping regions (if same lock type) */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 if (request->fl_type == fl->fl_type) {
Olaf Kirch449231d2005-08-25 16:25:35 -07001041 /* In all comparisons of start vs end, use
1042 * "start - 1" rather than "end + 1". If end
1043 * is OFFSET_MAX, end + 1 will become negative.
1044 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 if (fl->fl_end < request->fl_start - 1)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001046 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 /* If the next lock in the list has entirely bigger
1048 * addresses than the new one, insert the lock here.
1049 */
Olaf Kirch449231d2005-08-25 16:25:35 -07001050 if (fl->fl_start - 1 > request->fl_end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 break;
1052
1053 /* If we come here, the new and old lock are of the
1054 * same type and adjacent or overlapping. Make one
1055 * lock yielding from the lower start address of both
1056 * locks to the higher end address.
1057 */
1058 if (fl->fl_start > request->fl_start)
1059 fl->fl_start = request->fl_start;
1060 else
1061 request->fl_start = fl->fl_start;
1062 if (fl->fl_end < request->fl_end)
1063 fl->fl_end = request->fl_end;
1064 else
1065 request->fl_end = fl->fl_end;
1066 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001067 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 continue;
1069 }
1070 request = fl;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001071 added = true;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001072 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 /* Processing for different lock types is a bit
1074 * more complex.
1075 */
1076 if (fl->fl_end < request->fl_start)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001077 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 if (fl->fl_start > request->fl_end)
1079 break;
1080 if (request->fl_type == F_UNLCK)
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001081 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 if (fl->fl_start < request->fl_start)
1083 left = fl;
1084 /* If the next lock in the list has a higher end
1085 * address than the new one, insert the new one here.
1086 */
1087 if (fl->fl_end > request->fl_end) {
1088 right = fl;
1089 break;
1090 }
1091 if (fl->fl_start >= request->fl_start) {
1092 /* The new lock completely replaces an old
1093 * one (This may happen several times).
1094 */
1095 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001096 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 continue;
1098 }
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001099 /*
1100 * Replace the old lock with new_fl, and
1101 * remove the old one. It's safe to do the
1102 * insert here since we know that we won't be
1103 * using new_fl later, and that the lock is
1104 * just replacing an existing lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 */
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001106 error = -ENOLCK;
1107 if (!new_fl)
1108 goto out;
1109 locks_copy_lock(new_fl, request);
1110 request = new_fl;
1111 new_fl = NULL;
Jeff Laytone084c1b2015-02-16 14:32:03 -05001112 locks_insert_lock_ctx(request, &fl->fl_list);
1113 locks_delete_lock_ctx(fl, &dispose);
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001114 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 }
1116 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 }
1118
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001119 /*
Jeff Layton1cb36012013-06-21 08:58:12 -04001120 * The above code only modifies existing locks in case of merging or
1121 * replacing. If new lock(s) need to be inserted all modifications are
1122 * done below this, so it's safe yet to bail out.
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001123 */
1124 error = -ENOLCK; /* "no luck" */
1125 if (right && left == right && !new_fl2)
1126 goto out;
1127
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 error = 0;
1129 if (!added) {
Trond Myklebustf475ae92006-06-29 16:38:32 -04001130 if (request->fl_type == F_UNLCK) {
1131 if (request->fl_flags & FL_EXISTS)
1132 error = -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -04001134 }
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001135
1136 if (!new_fl) {
1137 error = -ENOLCK;
1138 goto out;
1139 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001141 locks_insert_lock_ctx(new_fl, &fl->fl_list);
Jeff Layton2e2f756f2015-02-17 17:08:23 -05001142 fl = new_fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 new_fl = NULL;
1144 }
1145 if (right) {
1146 if (left == right) {
1147 /* The new lock breaks the old one in two pieces,
1148 * so we have to use the second new lock.
1149 */
1150 left = new_fl2;
1151 new_fl2 = NULL;
1152 locks_copy_lock(left, right);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001153 locks_insert_lock_ctx(left, &fl->fl_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 }
1155 right->fl_start = request->fl_end + 1;
1156 locks_wake_up_blocks(right);
1157 }
1158 if (left) {
1159 left->fl_end = request->fl_start - 1;
1160 locks_wake_up_blocks(left);
1161 }
1162 out:
Jeff Layton6109c852015-01-16 15:05:57 -05001163 spin_unlock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 /*
1165 * Free any unused locks.
1166 */
1167 if (new_fl)
1168 locks_free_lock(new_fl);
1169 if (new_fl2)
1170 locks_free_lock(new_fl2);
Jeff Laytoned9814d2014-08-11 14:20:31 -04001171 locks_dispose_list(&dispose);
Jeff Layton18909102016-01-06 21:26:10 -05001172 trace_posix_lock_inode(inode, request, error);
1173
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 return error;
1175}
1176
1177/**
1178 * posix_lock_file - Apply a POSIX-style lock to a file
1179 * @filp: The file to apply the lock to
1180 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05001181 * @conflock: Place to return a copy of the conflicting lock, if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 *
1183 * Add a POSIX style lock to a file.
1184 * We merge adjacent & overlapping locks whenever possible.
1185 * POSIX locks are sorted by owner task, then by starting address
Trond Myklebustf475ae92006-06-29 16:38:32 -04001186 *
1187 * Note that if called with an FL_EXISTS argument, the caller may determine
1188 * whether or not a lock was successfully freed by testing the return
1189 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 */
Marc Eshel150b3932007-01-18 16:15:35 -05001191int posix_lock_file(struct file *filp, struct file_lock *fl,
Andy Adamson5842add2006-03-26 01:37:26 -08001192 struct file_lock *conflock)
1193{
Al Viro496ad9a2013-01-23 17:07:38 -05001194 return __posix_lock_file(file_inode(filp), fl, conflock);
Andy Adamson5842add2006-03-26 01:37:26 -08001195}
Marc Eshel150b3932007-01-18 16:15:35 -05001196EXPORT_SYMBOL(posix_lock_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197
1198/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001199 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1200 * @inode: inode of file to which lock request should be applied
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 * @fl: The lock to be applied
1202 *
Benjamin Coddington616fb382015-10-22 13:38:15 -04001203 * Apply a POSIX style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001205static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206{
1207 int error;
1208 might_sleep ();
1209 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001210 error = __posix_lock_file(inode, fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001211 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 break;
1213 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1214 if (!error)
1215 continue;
1216
1217 locks_delete_block(fl);
1218 break;
1219 }
1220 return error;
1221}
Jeff Layton29d01b22015-07-11 06:43:02 -04001222
Jeff Layton9e8925b2015-11-16 09:49:34 -05001223#ifdef CONFIG_MANDATORY_FILE_LOCKING
Jeff Layton29d01b22015-07-11 06:43:02 -04001224/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 * locks_mandatory_locked - Check for an active lock
Jeff Laytond7a06982014-03-10 09:54:15 -04001226 * @file: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 *
1228 * Searches the inode's list of locks to find any POSIX locks which conflict.
1229 * This function is called from locks_verify_locked() only.
1230 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001231int locks_mandatory_locked(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001233 int ret;
Jeff Laytond7a06982014-03-10 09:54:15 -04001234 struct inode *inode = file_inode(file);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001235 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 struct file_lock *fl;
1237
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001238 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001239 if (!ctx || list_empty_careful(&ctx->flc_posix))
1240 return 0;
1241
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 /*
1243 * Search the lock list for this inode for any POSIX locks.
1244 */
Jeff Layton6109c852015-01-16 15:05:57 -05001245 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001246 ret = 0;
1247 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001248 if (fl->fl_owner != current->files &&
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001249 fl->fl_owner != file) {
1250 ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 break;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001252 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 }
Jeff Layton6109c852015-01-16 15:05:57 -05001254 spin_unlock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001255 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256}
1257
1258/**
1259 * locks_mandatory_area - Check for a conflicting lock
1260 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1261 * for shared
1262 * @inode: the file to check
1263 * @filp: how the file was opened (if it was)
1264 * @offset: start of area to check
1265 * @count: length of area to check
1266 *
1267 * Searches the inode's list of locks to find any POSIX locks which conflict.
1268 * This function is called from rw_verify_area() and
1269 * locks_verify_truncate().
1270 */
1271int locks_mandatory_area(int read_write, struct inode *inode,
1272 struct file *filp, loff_t offset,
1273 size_t count)
1274{
1275 struct file_lock fl;
1276 int error;
Jeff Layton29723ad2014-03-10 09:54:19 -04001277 bool sleep = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278
1279 locks_init_lock(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 fl.fl_pid = current->tgid;
1281 fl.fl_file = filp;
1282 fl.fl_flags = FL_POSIX | FL_ACCESS;
1283 if (filp && !(filp->f_flags & O_NONBLOCK))
Jeff Layton29723ad2014-03-10 09:54:19 -04001284 sleep = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1286 fl.fl_start = offset;
1287 fl.fl_end = offset + count - 1;
1288
1289 for (;;) {
Jeff Layton29723ad2014-03-10 09:54:19 -04001290 if (filp) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001291 fl.fl_owner = filp;
Jeff Layton29723ad2014-03-10 09:54:19 -04001292 fl.fl_flags &= ~FL_SLEEP;
1293 error = __posix_lock_file(inode, &fl, NULL);
1294 if (!error)
1295 break;
1296 }
1297
1298 if (sleep)
1299 fl.fl_flags |= FL_SLEEP;
1300 fl.fl_owner = current->files;
Marc Eshel150b3932007-01-18 16:15:35 -05001301 error = __posix_lock_file(inode, &fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001302 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 break;
1304 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1305 if (!error) {
1306 /*
1307 * If we've been sleeping someone might have
1308 * changed the permissions behind our back.
1309 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07001310 if (__mandatory_lock(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 continue;
1312 }
1313
1314 locks_delete_block(&fl);
1315 break;
1316 }
1317
1318 return error;
1319}
1320
1321EXPORT_SYMBOL(locks_mandatory_area);
Jeff Layton9e8925b2015-11-16 09:49:34 -05001322#endif /* CONFIG_MANDATORY_FILE_LOCKING */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323
J. Bruce Fields778fc542011-07-26 18:25:49 -04001324static void lease_clear_pending(struct file_lock *fl, int arg)
1325{
1326 switch (arg) {
1327 case F_UNLCK:
1328 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1329 /* fall through: */
1330 case F_RDLCK:
1331 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1332 }
1333}
1334
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335/* We already had a lease on this file; just change its type */
Jeff Layton7448cc32015-01-16 15:05:57 -05001336int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 int error = assign_type(fl, arg);
1339
1340 if (error)
1341 return error;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001342 lease_clear_pending(fl, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 locks_wake_up_blocks(fl);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001344 if (arg == F_UNLCK) {
1345 struct file *filp = fl->fl_file;
1346
1347 f_delown(filp);
1348 filp->f_owner.signum = 0;
J. Bruce Fields96d6d592012-07-27 16:18:00 -04001349 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1350 if (fl->fl_fasync != NULL) {
1351 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1352 fl->fl_fasync = NULL;
1353 }
Jeff Laytone084c1b2015-02-16 14:32:03 -05001354 locks_delete_lock_ctx(fl, dispose);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001355 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 return 0;
1357}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358EXPORT_SYMBOL(lease_modify);
1359
J. Bruce Fields778fc542011-07-26 18:25:49 -04001360static bool past_time(unsigned long then)
1361{
1362 if (!then)
1363 /* 0 is a special value meaning "this never expires": */
1364 return false;
1365 return time_after(jiffies, then);
1366}
1367
Jeff Laytonc45198e2014-09-01 07:12:07 -04001368static void time_out_leases(struct inode *inode, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369{
Jeff Layton8634b512015-01-16 15:05:55 -05001370 struct file_lock_context *ctx = inode->i_flctx;
1371 struct file_lock *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372
Jeff Layton6109c852015-01-16 15:05:57 -05001373 lockdep_assert_held(&ctx->flc_lock);
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001374
Jeff Layton8634b512015-01-16 15:05:55 -05001375 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001376 trace_time_out_leases(inode, fl);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001377 if (past_time(fl->fl_downgrade_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001378 lease_modify(fl, F_RDLCK, dispose);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001379 if (past_time(fl->fl_break_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001380 lease_modify(fl, F_UNLCK, dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 }
1382}
1383
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001384static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1385{
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001386 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1387 return false;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001388 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1389 return false;
1390 return locks_conflict(breaker, lease);
1391}
1392
Jeff Layton03d12dd2014-09-01 14:53:41 -04001393static bool
1394any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1395{
Jeff Layton8634b512015-01-16 15:05:55 -05001396 struct file_lock_context *ctx = inode->i_flctx;
Jeff Layton03d12dd2014-09-01 14:53:41 -04001397 struct file_lock *fl;
1398
Jeff Layton6109c852015-01-16 15:05:57 -05001399 lockdep_assert_held(&ctx->flc_lock);
Jeff Layton03d12dd2014-09-01 14:53:41 -04001400
Jeff Layton8634b512015-01-16 15:05:55 -05001401 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Jeff Layton03d12dd2014-09-01 14:53:41 -04001402 if (leases_conflict(fl, breaker))
1403 return true;
1404 }
1405 return false;
1406}
1407
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408/**
1409 * __break_lease - revoke all outstanding leases on file
1410 * @inode: the inode of the file to return
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001411 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1412 * break all leases
1413 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1414 * only delegations
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415 *
david m. richter87250dd2007-05-09 16:10:27 -04001416 * break_lease (inlined for speed) has checked there already is at least
1417 * some kind of lock (maybe a lease) on this file. Leases are broken on
1418 * a call to open() or truncate(). This function can sleep unless you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 * specified %O_NONBLOCK to your open().
1420 */
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001421int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422{
J. Bruce Fields778fc542011-07-26 18:25:49 -04001423 int error = 0;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001424 struct file_lock_context *ctx;
Yan, Zhenga9011252015-03-27 10:34:20 +08001425 struct file_lock *new_fl, *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 unsigned long break_time;
Al Viro8737c932009-12-24 06:47:55 -05001427 int want_write = (mode & O_ACCMODE) != O_RDONLY;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001428 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429
Al Viro8737c932009-12-24 06:47:55 -05001430 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001431 if (IS_ERR(new_fl))
1432 return PTR_ERR(new_fl);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001433 new_fl->fl_flags = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434
Jeff Layton8634b512015-01-16 15:05:55 -05001435 /* typically we will check that ctx is non-NULL before calling */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001436 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001437 if (!ctx) {
1438 WARN_ON_ONCE(1);
1439 return error;
1440 }
1441
Jeff Layton6109c852015-01-16 15:05:57 -05001442 spin_lock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443
Jeff Laytonc45198e2014-09-01 07:12:07 -04001444 time_out_leases(inode, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445
Jeff Layton03d12dd2014-09-01 14:53:41 -04001446 if (!any_leases_conflict(inode, new_fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001447 goto out;
1448
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 break_time = 0;
1450 if (lease_break_time > 0) {
1451 break_time = jiffies + lease_break_time * HZ;
1452 if (break_time == 0)
1453 break_time++; /* so that 0 means no break time */
1454 }
1455
Yan, Zhenga9011252015-03-27 10:34:20 +08001456 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001457 if (!leases_conflict(fl, new_fl))
1458 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001459 if (want_write) {
1460 if (fl->fl_flags & FL_UNLOCK_PENDING)
1461 continue;
1462 fl->fl_flags |= FL_UNLOCK_PENDING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463 fl->fl_break_time = break_time;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001464 } else {
Jeff Layton8634b512015-01-16 15:05:55 -05001465 if (lease_breaking(fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001466 continue;
1467 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1468 fl->fl_downgrade_time = break_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 }
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001470 if (fl->fl_lmops->lm_break(fl))
Jeff Laytone084c1b2015-02-16 14:32:03 -05001471 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 }
1473
Jeff Layton8634b512015-01-16 15:05:55 -05001474 if (list_empty(&ctx->flc_lease))
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001475 goto out;
1476
Jeff Layton843c6b22014-09-01 14:27:43 -04001477 if (mode & O_NONBLOCK) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001478 trace_break_lease_noblock(inode, new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 error = -EWOULDBLOCK;
1480 goto out;
1481 }
1482
1483restart:
Jeff Layton8634b512015-01-16 15:05:55 -05001484 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1485 break_time = fl->fl_break_time;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001486 if (break_time != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 break_time -= jiffies;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001488 if (break_time == 0)
1489 break_time++;
Jeff Layton8634b512015-01-16 15:05:55 -05001490 locks_insert_block(fl, new_fl);
Jeff Layton62af4f12014-05-09 14:13:05 -04001491 trace_break_lease_block(inode, new_fl);
Jeff Layton6109c852015-01-16 15:05:57 -05001492 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001493 locks_dispose_list(&dispose);
Matthew Wilcox4321e012008-01-14 21:28:30 -07001494 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1495 !new_fl->fl_next, break_time);
Jeff Layton6109c852015-01-16 15:05:57 -05001496 spin_lock(&ctx->flc_lock);
Jeff Layton62af4f12014-05-09 14:13:05 -04001497 trace_break_lease_unblock(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001498 locks_delete_block(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499 if (error >= 0) {
J. Bruce Fields778fc542011-07-26 18:25:49 -04001500 /*
1501 * Wait for the next conflicting lease that has not been
1502 * broken yet
1503 */
Jeff Layton03d12dd2014-09-01 14:53:41 -04001504 if (error == 0)
1505 time_out_leases(inode, &dispose);
1506 if (any_leases_conflict(inode, new_fl))
1507 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 error = 0;
1509 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510out:
Jeff Layton6109c852015-01-16 15:05:57 -05001511 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001512 locks_dispose_list(&dispose);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001513 locks_free_lock(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514 return error;
1515}
1516
1517EXPORT_SYMBOL(__break_lease);
1518
1519/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001520 * lease_get_mtime - get the last modified time of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521 * @inode: the inode
1522 * @time: pointer to a timespec which will contain the last modified time
1523 *
1524 * This is to force NFS clients to flush their caches for files with
1525 * exclusive leases. The justification is that if someone has an
Randy Dunlapa6b91912008-03-19 17:01:00 -07001526 * exclusive lease, then they could be modifying it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 */
1528void lease_get_mtime(struct inode *inode, struct timespec *time)
1529{
Jeff Laytonbfe86022014-08-22 10:18:44 -04001530 bool has_lease = false;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001531 struct file_lock_context *ctx;
Jeff Layton8634b512015-01-16 15:05:55 -05001532 struct file_lock *fl;
Jeff Laytonbfe86022014-08-22 10:18:44 -04001533
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001534 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001535 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001536 spin_lock(&ctx->flc_lock);
Geliang Tang8ace5df2015-11-18 21:40:33 +08001537 fl = list_first_entry_or_null(&ctx->flc_lease,
1538 struct file_lock, fl_list);
1539 if (fl && (fl->fl_type == F_WRLCK))
1540 has_lease = true;
Jeff Layton6109c852015-01-16 15:05:57 -05001541 spin_unlock(&ctx->flc_lock);
Jeff Laytonbfe86022014-08-22 10:18:44 -04001542 }
1543
1544 if (has_lease)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545 *time = current_fs_time(inode->i_sb);
1546 else
1547 *time = inode->i_mtime;
1548}
1549
1550EXPORT_SYMBOL(lease_get_mtime);
1551
1552/**
1553 * fcntl_getlease - Enquire what lease is currently active
1554 * @filp: the file
1555 *
1556 * The value returned by this function will be one of
1557 * (if no lease break is pending):
1558 *
1559 * %F_RDLCK to indicate a shared lease is held.
1560 *
1561 * %F_WRLCK to indicate an exclusive lease is held.
1562 *
1563 * %F_UNLCK to indicate no lease is held.
1564 *
1565 * (if a lease break is pending):
1566 *
1567 * %F_RDLCK to indicate an exclusive lease needs to be
1568 * changed to a shared lease (or removed).
1569 *
1570 * %F_UNLCK to indicate the lease needs to be removed.
1571 *
1572 * XXX: sfr & willy disagree over whether F_INPROGRESS
1573 * should be returned to userspace.
1574 */
1575int fcntl_getlease(struct file *filp)
1576{
1577 struct file_lock *fl;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001578 struct inode *inode = file_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001579 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580 int type = F_UNLCK;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001581 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001583 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001584 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001585 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001586 time_out_leases(file_inode(filp), &dispose);
1587 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1588 if (fl->fl_file != filp)
1589 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001590 type = target_leasetype(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001591 break;
1592 }
Jeff Layton6109c852015-01-16 15:05:57 -05001593 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001594 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596 return type;
1597}
1598
Jeff Layton24cbe782014-02-03 12:13:06 -05001599/**
1600 * check_conflicting_open - see if the given dentry points to a file that has
1601 * an existing open that would conflict with the
1602 * desired lease.
1603 * @dentry: dentry to check
1604 * @arg: type of lease that we're trying to acquire
Randy Dunlap7fadc592015-08-09 18:43:17 -07001605 * @flags: current lock flags
Jeff Layton24cbe782014-02-03 12:13:06 -05001606 *
1607 * Check to see if there's an existing open fd on this file that would
1608 * conflict with the lease we're trying to set.
1609 */
1610static int
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001611check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
Jeff Layton24cbe782014-02-03 12:13:06 -05001612{
1613 int ret = 0;
1614 struct inode *inode = dentry->d_inode;
1615
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001616 if (flags & FL_LAYOUT)
1617 return 0;
1618
Jeff Layton24cbe782014-02-03 12:13:06 -05001619 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1620 return -EAGAIN;
1621
1622 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1623 (atomic_read(&inode->i_count) > 1)))
1624 ret = -EAGAIN;
1625
1626 return ret;
1627}
1628
Jeff Laytone6f5c782014-08-22 10:40:25 -04001629static int
1630generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631{
Jeff Layton8634b512015-01-16 15:05:55 -05001632 struct file_lock *fl, *my_fl = NULL, *lease;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001633 struct dentry *dentry = filp->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634 struct inode *inode = dentry->d_inode;
Jeff Layton8634b512015-01-16 15:05:55 -05001635 struct file_lock_context *ctx;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001636 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001637 int error;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001638 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639
J. Bruce Fields096657b2010-10-30 17:31:14 -04001640 lease = *flp;
Jeff Layton62af4f12014-05-09 14:13:05 -04001641 trace_generic_add_lease(inode, lease);
1642
Jeff Layton5c1c6692015-04-03 09:04:03 -04001643 /* Note that arg is never F_UNLCK here */
1644 ctx = locks_get_lock_context(inode, arg);
Jeff Layton8634b512015-01-16 15:05:55 -05001645 if (!ctx)
1646 return -ENOMEM;
1647
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001648 /*
1649 * In the delegation case we need mutual exclusion with
1650 * a number of operations that take the i_mutex. We trylock
1651 * because delegations are an optional optimization, and if
1652 * there's some chance of a conflict--we'd rather not
1653 * bother, maybe that's a sign this just isn't a good file to
1654 * hand out a delegation on.
1655 */
1656 if (is_deleg && !mutex_trylock(&inode->i_mutex))
1657 return -EAGAIN;
1658
1659 if (is_deleg && arg == F_WRLCK) {
1660 /* Write delegations are not currently supported: */
Dan Carpenter4fdb7932013-11-13 10:56:27 +03001661 mutex_unlock(&inode->i_mutex);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001662 WARN_ON_ONCE(1);
1663 return -EINVAL;
1664 }
J. Bruce Fields096657b2010-10-30 17:31:14 -04001665
Jeff Layton6109c852015-01-16 15:05:57 -05001666 spin_lock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001667 time_out_leases(inode, &dispose);
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001668 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton24cbe782014-02-03 12:13:06 -05001669 if (error)
J. Bruce Fields096657b2010-10-30 17:31:14 -04001670 goto out;
Pavel Emelyanov85c59582007-09-20 12:45:02 +04001671
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672 /*
1673 * At this point, we know that if there is an exclusive
1674 * lease on this file, then we hold it on this filp
1675 * (otherwise our open of this file would have blocked).
1676 * And if we are trying to acquire an exclusive lease,
1677 * then the file is not open by anyone (including us)
1678 * except for this filp.
1679 */
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001680 error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001681 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001682 if (fl->fl_file == filp &&
1683 fl->fl_owner == lease->fl_owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001684 my_fl = fl;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001685 continue;
1686 }
Jeff Layton8634b512015-01-16 15:05:55 -05001687
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001688 /*
1689 * No exclusive leases if someone else has a lease on
1690 * this file:
1691 */
1692 if (arg == F_WRLCK)
1693 goto out;
1694 /*
1695 * Modifying our existing lease is OK, but no getting a
1696 * new lease if someone else is opening for write:
1697 */
1698 if (fl->fl_flags & FL_UNLOCK_PENDING)
1699 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700 }
1701
Jeff Layton8634b512015-01-16 15:05:55 -05001702 if (my_fl != NULL) {
Jeff Layton0164bf02015-03-04 17:34:32 -05001703 lease = my_fl;
1704 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001705 if (error)
1706 goto out;
1707 goto out_setup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708 }
1709
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 error = -EINVAL;
1711 if (!leases_enable)
1712 goto out;
1713
Jeff Laytone084c1b2015-02-16 14:32:03 -05001714 locks_insert_lock_ctx(lease, &ctx->flc_lease);
Jeff Layton24cbe782014-02-03 12:13:06 -05001715 /*
1716 * The check in break_lease() is lockless. It's possible for another
1717 * open to race in after we did the earlier check for a conflicting
1718 * open but before the lease was inserted. Check again for a
1719 * conflicting open and cancel the lease if there is one.
1720 *
1721 * We also add a barrier here to ensure that the insertion of the lock
1722 * precedes these checks.
1723 */
1724 smp_mb();
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001725 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton8634b512015-01-16 15:05:55 -05001726 if (error) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001727 locks_unlink_lock_ctx(lease);
Jeff Layton8634b512015-01-16 15:05:55 -05001728 goto out;
1729 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001730
1731out_setup:
1732 if (lease->fl_lmops->lm_setup)
1733 lease->fl_lmops->lm_setup(lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734out:
Jeff Layton6109c852015-01-16 15:05:57 -05001735 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001736 locks_dispose_list(&dispose);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001737 if (is_deleg)
1738 mutex_unlock(&inode->i_mutex);
Jeff Layton8634b512015-01-16 15:05:55 -05001739 if (!error && !my_fl)
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001740 *flp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 return error;
1742}
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001743
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001744static int generic_delete_lease(struct file *filp, void *owner)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001745{
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001746 int error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001747 struct file_lock *fl, *victim = NULL;
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04001748 struct inode *inode = file_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001749 struct file_lock_context *ctx;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001750 LIST_HEAD(dispose);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001751
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001752 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001753 if (!ctx) {
1754 trace_generic_delete_lease(inode, NULL);
1755 return error;
1756 }
1757
Jeff Layton6109c852015-01-16 15:05:57 -05001758 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001759 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001760 if (fl->fl_file == filp &&
1761 fl->fl_owner == owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001762 victim = fl;
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001763 break;
Jeff Layton8634b512015-01-16 15:05:55 -05001764 }
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001765 }
Jeff Laytona9b1b452015-03-14 09:45:35 -04001766 trace_generic_delete_lease(inode, victim);
Jeff Layton8634b512015-01-16 15:05:55 -05001767 if (victim)
Jeff Layton7448cc32015-01-16 15:05:57 -05001768 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05001769 spin_unlock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001770 locks_dispose_list(&dispose);
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001771 return error;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001772}
1773
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774/**
1775 * generic_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001776 * @filp: file pointer
1777 * @arg: type of lease to obtain
1778 * @flp: input - file_lock to use, output - file_lock inserted
1779 * @priv: private data for lm_setup (may be NULL if lm_setup
1780 * doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 *
1782 * The (input) flp->fl_lmops->lm_break function is required
1783 * by break_lease().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001785int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1786 void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787{
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04001788 struct inode *inode = file_inode(filp);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001789 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790
Eric W. Biederman8e96e3b2012-03-03 21:17:15 -08001791 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001792 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001793 if (!S_ISREG(inode->i_mode))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001794 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 error = security_file_lock(filp, arg);
1796 if (error)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001797 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001799 switch (arg) {
1800 case F_UNLCK:
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001801 return generic_delete_lease(filp, *priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001802 case F_RDLCK:
1803 case F_WRLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001804 if (!(*flp)->fl_lmops->lm_break) {
1805 WARN_ON_ONCE(1);
1806 return -ENOLCK;
1807 }
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001808
Jeff Laytone6f5c782014-08-22 10:40:25 -04001809 return generic_add_lease(filp, arg, flp, priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001810 default:
Dave Jones8d657eb2012-07-13 13:35:36 -04001811 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001812 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813}
Christoph Hellwig0af1a452007-07-31 00:39:22 -07001814EXPORT_SYMBOL(generic_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815
Arnd Bergmannb89f4322010-09-18 15:09:31 +02001816/**
Jeff Laytone51673a2014-08-22 18:13:28 -04001817 * vfs_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001818 * @filp: file pointer
1819 * @arg: type of lease to obtain
1820 * @lease: file_lock to use when adding a lease
1821 * @priv: private info for lm_setup when adding a lease (may be
1822 * NULL if lm_setup doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823 *
Jeff Laytone51673a2014-08-22 18:13:28 -04001824 * Call this to establish a lease on the file. The "lease" argument is not
1825 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1826 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1827 * if not, this function will return -ENOLCK (and generate a scary-looking
1828 * stack trace).
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001829 *
1830 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1831 * may be NULL if the lm_setup operation doesn't require it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001833int
1834vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001836 if (filp->f_op->setlease)
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001837 return filp->f_op->setlease(filp, arg, lease, priv);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001838 else
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001839 return generic_setlease(filp, arg, lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840}
J. Bruce Fieldsa9933ce2007-06-07 17:09:49 -04001841EXPORT_SYMBOL_GPL(vfs_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001843static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001845 struct file_lock *fl;
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001846 struct fasync_struct *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847 int error;
1848
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001849 fl = lease_alloc(filp, arg);
1850 if (IS_ERR(fl))
1851 return PTR_ERR(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001853 new = fasync_alloc();
1854 if (!new) {
1855 locks_free_lock(fl);
1856 return -ENOMEM;
1857 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001858 new->fa_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001860 error = vfs_setlease(filp, arg, &fl, (void **)&new);
Jeff Layton2dfb9282014-08-11 18:14:12 -04001861 if (fl)
1862 locks_free_lock(fl);
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001863 if (new)
1864 fasync_free(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 return error;
1866}
1867
1868/**
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001869 * fcntl_setlease - sets a lease on an open file
1870 * @fd: open file descriptor
1871 * @filp: file pointer
1872 * @arg: type of lease to obtain
1873 *
1874 * Call this fcntl to establish a lease on the file.
1875 * Note that you also need to call %F_SETSIG to
1876 * receive a signal when the lease is broken.
1877 */
1878int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1879{
1880 if (arg == F_UNLCK)
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001881 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001882 return do_fcntl_add_lease(fd, filp, arg);
1883}
1884
1885/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001886 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1887 * @inode: inode of the file to apply to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 * @fl: The lock to be applied
1889 *
Jeff Layton29d01b22015-07-11 06:43:02 -04001890 * Apply a FLOCK style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001892static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893{
1894 int error;
1895 might_sleep();
1896 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001897 error = flock_lock_inode(inode, fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001898 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899 break;
1900 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1901 if (!error)
1902 continue;
1903
1904 locks_delete_block(fl);
1905 break;
1906 }
1907 return error;
1908}
1909
Jeff Layton29d01b22015-07-11 06:43:02 -04001910/**
Benjamin Coddingtone55c34a2015-10-22 13:38:13 -04001911 * locks_lock_inode_wait - Apply a lock to an inode
1912 * @inode: inode of the file to apply to
1913 * @fl: The lock to be applied
1914 *
1915 * Apply a POSIX or FLOCK style lock request to an inode.
1916 */
1917int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1918{
1919 int res = 0;
1920 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1921 case FL_POSIX:
1922 res = posix_lock_inode_wait(inode, fl);
1923 break;
1924 case FL_FLOCK:
1925 res = flock_lock_inode_wait(inode, fl);
1926 break;
1927 default:
1928 BUG();
1929 }
1930 return res;
1931}
1932EXPORT_SYMBOL(locks_lock_inode_wait);
1933
1934/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935 * sys_flock: - flock() system call.
1936 * @fd: the file descriptor to lock.
1937 * @cmd: the type of lock to apply.
1938 *
1939 * Apply a %FL_FLOCK style lock to an open file descriptor.
1940 * The @cmd can be one of
1941 *
1942 * %LOCK_SH -- a shared lock.
1943 *
1944 * %LOCK_EX -- an exclusive lock.
1945 *
1946 * %LOCK_UN -- remove an existing lock.
1947 *
1948 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1949 *
1950 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1951 * processes read and write access respectively.
1952 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001953SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954{
Al Viro2903ff02012-08-28 12:52:22 -04001955 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 struct file_lock *lock;
1957 int can_sleep, unlock;
1958 int error;
1959
1960 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001961 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 goto out;
1963
1964 can_sleep = !(cmd & LOCK_NB);
1965 cmd &= ~LOCK_NB;
1966 unlock = (cmd == LOCK_UN);
1967
Al Viroaeb5d722008-09-02 15:28:45 -04001968 if (!unlock && !(cmd & LOCK_MAND) &&
Al Viro2903ff02012-08-28 12:52:22 -04001969 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970 goto out_putf;
1971
Jeff Layton6e129d002014-09-04 10:25:06 -04001972 lock = flock_make_lock(f.file, cmd);
1973 if (IS_ERR(lock)) {
1974 error = PTR_ERR(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 goto out_putf;
Jeff Layton6e129d002014-09-04 10:25:06 -04001976 }
1977
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 if (can_sleep)
1979 lock->fl_flags |= FL_SLEEP;
1980
Al Viro2903ff02012-08-28 12:52:22 -04001981 error = security_file_lock(f.file, lock->fl_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982 if (error)
1983 goto out_free;
1984
Al Viro72c2d532013-09-22 16:27:52 -04001985 if (f.file->f_op->flock)
Al Viro2903ff02012-08-28 12:52:22 -04001986 error = f.file->f_op->flock(f.file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987 (can_sleep) ? F_SETLKW : F_SETLK,
1988 lock);
1989 else
Benjamin Coddington4f656362015-10-22 13:38:14 -04001990 error = locks_lock_file_wait(f.file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991
1992 out_free:
Trond Myklebust993dfa82006-03-31 02:30:55 -08001993 locks_free_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994
1995 out_putf:
Al Viro2903ff02012-08-28 12:52:22 -04001996 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001997 out:
1998 return error;
1999}
2000
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002001/**
2002 * vfs_test_lock - test file byte range lock
2003 * @filp: The file to test lock for
J. Bruce Fields6924c552007-05-11 16:22:50 -04002004 * @fl: The lock to test; also used to hold result
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002005 *
2006 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2007 * setting conf->fl_type to something other than F_UNLCK.
2008 */
2009int vfs_test_lock(struct file *filp, struct file_lock *fl)
2010{
Al Viro72c2d532013-09-22 16:27:52 -04002011 if (filp->f_op->lock)
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002012 return filp->f_op->lock(filp, F_GETLK, fl);
2013 posix_test_lock(filp, fl);
2014 return 0;
2015}
2016EXPORT_SYMBOL_GPL(vfs_test_lock);
2017
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002018static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2019{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002020 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002021#if BITS_PER_LONG == 32
2022 /*
2023 * Make sure we can represent the posix lock via
2024 * legacy 32bit flock.
2025 */
2026 if (fl->fl_start > OFFT_OFFSET_MAX)
2027 return -EOVERFLOW;
2028 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2029 return -EOVERFLOW;
2030#endif
2031 flock->l_start = fl->fl_start;
2032 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2033 fl->fl_end - fl->fl_start + 1;
2034 flock->l_whence = 0;
J. Bruce Fields129a84d2007-05-10 18:38:43 -04002035 flock->l_type = fl->fl_type;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002036 return 0;
2037}
2038
2039#if BITS_PER_LONG == 32
2040static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2041{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002042 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002043 flock->l_start = fl->fl_start;
2044 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2045 fl->fl_end - fl->fl_start + 1;
2046 flock->l_whence = 0;
2047 flock->l_type = fl->fl_type;
2048}
2049#endif
2050
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051/* Report the first existing lock that would conflict with l.
2052 * This implements the F_GETLK command of fcntl().
2053 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002054int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002056 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002057 struct flock flock;
2058 int error;
2059
2060 error = -EFAULT;
2061 if (copy_from_user(&flock, l, sizeof(flock)))
2062 goto out;
2063 error = -EINVAL;
2064 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2065 goto out;
2066
2067 error = flock_to_posix_lock(filp, &file_lock, &flock);
2068 if (error)
2069 goto out;
2070
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002071 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002072 error = -EINVAL;
2073 if (flock.l_pid != 0)
2074 goto out;
2075
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002076 cmd = F_GETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002077 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002078 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002079 }
2080
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002081 error = vfs_test_lock(filp, &file_lock);
2082 if (error)
2083 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002084
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002085 flock.l_type = file_lock.fl_type;
2086 if (file_lock.fl_type != F_UNLCK) {
2087 error = posix_lock_to_flock(&flock, &file_lock);
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002088 if (error)
Kinglong Meef3282962014-08-22 10:18:43 -04002089 goto rel_priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002090 }
2091 error = -EFAULT;
2092 if (!copy_to_user(l, &flock, sizeof(flock)))
2093 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002094rel_priv:
2095 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096out:
2097 return error;
2098}
2099
Marc Eshel7723ec92007-01-18 15:08:55 -05002100/**
2101 * vfs_lock_file - file byte range lock
2102 * @filp: The file to apply the lock to
2103 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2104 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05002105 * @conf: Place to return a copy of the conflicting lock, if found.
2106 *
2107 * A caller that doesn't care about the conflicting lock may pass NULL
2108 * as the final argument.
2109 *
2110 * If the filesystem defines a private ->lock() method, then @conf will
2111 * be left unchanged; so a caller that cares should initialize it to
2112 * some acceptable default.
Marc Eshel2beb6612006-12-05 23:31:28 -05002113 *
2114 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2115 * locks, the ->lock() interface may return asynchronously, before the lock has
2116 * been granted or denied by the underlying filesystem, if (and only if)
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002117 * lm_grant is set. Callers expecting ->lock() to return asynchronously
Marc Eshel2beb6612006-12-05 23:31:28 -05002118 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2119 * the request is for a blocking lock. When ->lock() does return asynchronously,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002120 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
Marc Eshel2beb6612006-12-05 23:31:28 -05002121 * request completes.
2122 * If the request is for non-blocking lock the file system should return
Miklos Szeredibde74e42008-07-25 01:48:57 -07002123 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2124 * with the result. If the request timed out the callback routine will return a
Marc Eshel2beb6612006-12-05 23:31:28 -05002125 * nonzero return code and the file system should release the lock. The file
2126 * system is also responsible to keep a corresponding posix lock when it
2127 * grants a lock so the VFS can find out which locks are locally held and do
2128 * the correct lock cleanup when required.
2129 * The underlying filesystem must not drop the kernel lock or call
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002130 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
Marc Eshel2beb6612006-12-05 23:31:28 -05002131 * return code.
Marc Eshel7723ec92007-01-18 15:08:55 -05002132 */
Marc Eshel150b3932007-01-18 16:15:35 -05002133int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
Marc Eshel7723ec92007-01-18 15:08:55 -05002134{
Al Viro72c2d532013-09-22 16:27:52 -04002135 if (filp->f_op->lock)
Marc Eshel7723ec92007-01-18 15:08:55 -05002136 return filp->f_op->lock(filp, cmd, fl);
2137 else
Marc Eshel150b3932007-01-18 16:15:35 -05002138 return posix_lock_file(filp, fl, conf);
Marc Eshel7723ec92007-01-18 15:08:55 -05002139}
2140EXPORT_SYMBOL_GPL(vfs_lock_file);
2141
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002142static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2143 struct file_lock *fl)
2144{
2145 int error;
2146
2147 error = security_file_lock(filp, fl->fl_type);
2148 if (error)
2149 return error;
2150
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002151 for (;;) {
2152 error = vfs_lock_file(filp, cmd, fl, NULL);
2153 if (error != FILE_LOCK_DEFERRED)
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002154 break;
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002155 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2156 if (!error)
2157 continue;
2158
2159 locks_delete_block(fl);
2160 break;
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002161 }
2162
2163 return error;
2164}
2165
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04002166/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002167static int
2168check_fmode_for_setlk(struct file_lock *fl)
2169{
2170 switch (fl->fl_type) {
2171 case F_RDLCK:
2172 if (!(fl->fl_file->f_mode & FMODE_READ))
2173 return -EBADF;
2174 break;
2175 case F_WRLCK:
2176 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2177 return -EBADF;
2178 }
2179 return 0;
2180}
2181
Linus Torvalds1da177e2005-04-16 15:20:36 -07002182/* Apply the lock described by l to an open file descriptor.
2183 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2184 */
Peter Staubachc2936212005-07-27 11:45:09 -07002185int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2186 struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002187{
2188 struct file_lock *file_lock = locks_alloc_lock();
2189 struct flock flock;
2190 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002191 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002192 int error;
2193
2194 if (file_lock == NULL)
2195 return -ENOLCK;
2196
Jeff Layton18909102016-01-06 21:26:10 -05002197 inode = file_inode(filp);
2198
Linus Torvalds1da177e2005-04-16 15:20:36 -07002199 /*
2200 * This might block, so we do it before checking the inode.
2201 */
2202 error = -EFAULT;
2203 if (copy_from_user(&flock, l, sizeof(flock)))
2204 goto out;
2205
Linus Torvalds1da177e2005-04-16 15:20:36 -07002206 /* Don't allow mandatory locks on files that may be memory mapped
2207 * and shared.
2208 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002209 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 error = -EAGAIN;
2211 goto out;
2212 }
2213
2214 error = flock_to_posix_lock(filp, file_lock, &flock);
2215 if (error)
2216 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002217
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002218 error = check_fmode_for_setlk(file_lock);
2219 if (error)
2220 goto out;
2221
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002222 /*
2223 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002224 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002225 */
2226 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002227 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002228 error = -EINVAL;
2229 if (flock.l_pid != 0)
2230 goto out;
2231
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002232 cmd = F_SETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002233 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002234 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002235 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002236 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002237 error = -EINVAL;
2238 if (flock.l_pid != 0)
2239 goto out;
2240
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002241 cmd = F_SETLKW;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002242 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002243 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002244 /* Fallthrough */
2245 case F_SETLKW:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002246 file_lock->fl_flags |= FL_SLEEP;
2247 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002248
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002249 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250
Peter Staubachc2936212005-07-27 11:45:09 -07002251 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002252 * Attempt to detect a close/fcntl race and recover by releasing the
2253 * lock that was just acquired. There is no need to do that when we're
2254 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002255 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002256 if (!error && file_lock->fl_type != F_UNLCK &&
2257 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002258 /*
2259 * We need that spin_lock here - it prevents reordering between
2260 * update of i_flctx->flc_posix and check for it done in
2261 * close(). rcu_read_lock() wouldn't do.
2262 */
2263 spin_lock(&current->files->file_lock);
2264 f = fcheck(fd);
2265 spin_unlock(&current->files->file_lock);
2266 if (f != filp) {
2267 file_lock->fl_type = F_UNLCK;
2268 error = do_lock_file_wait(filp, cmd, file_lock);
2269 WARN_ON_ONCE(error);
2270 error = -EBADF;
2271 }
Peter Staubachc2936212005-07-27 11:45:09 -07002272 }
Peter Staubachc2936212005-07-27 11:45:09 -07002273out:
Jeff Layton18909102016-01-06 21:26:10 -05002274 trace_fcntl_setlk(inode, file_lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275 locks_free_lock(file_lock);
2276 return error;
2277}
2278
2279#if BITS_PER_LONG == 32
2280/* Report the first existing lock that would conflict with l.
2281 * This implements the F_GETLK command of fcntl().
2282 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002283int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002285 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286 struct flock64 flock;
2287 int error;
2288
2289 error = -EFAULT;
2290 if (copy_from_user(&flock, l, sizeof(flock)))
2291 goto out;
2292 error = -EINVAL;
2293 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2294 goto out;
2295
2296 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2297 if (error)
2298 goto out;
2299
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002300 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002301 error = -EINVAL;
2302 if (flock.l_pid != 0)
2303 goto out;
2304
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002305 cmd = F_GETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002306 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002307 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002308 }
2309
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002310 error = vfs_test_lock(filp, &file_lock);
2311 if (error)
2312 goto out;
2313
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002314 flock.l_type = file_lock.fl_type;
2315 if (file_lock.fl_type != F_UNLCK)
2316 posix_lock_to_flock64(&flock, &file_lock);
2317
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318 error = -EFAULT;
2319 if (!copy_to_user(l, &flock, sizeof(flock)))
2320 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002321
2322 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002323out:
2324 return error;
2325}
2326
2327/* Apply the lock described by l to an open file descriptor.
2328 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2329 */
Peter Staubachc2936212005-07-27 11:45:09 -07002330int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2331 struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002332{
2333 struct file_lock *file_lock = locks_alloc_lock();
2334 struct flock64 flock;
2335 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002336 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002337 int error;
2338
2339 if (file_lock == NULL)
2340 return -ENOLCK;
2341
2342 /*
2343 * This might block, so we do it before checking the inode.
2344 */
2345 error = -EFAULT;
2346 if (copy_from_user(&flock, l, sizeof(flock)))
2347 goto out;
2348
Al Viro496ad9a2013-01-23 17:07:38 -05002349 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350
2351 /* Don't allow mandatory locks on files that may be memory mapped
2352 * and shared.
2353 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002354 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002355 error = -EAGAIN;
2356 goto out;
2357 }
2358
2359 error = flock64_to_posix_lock(filp, file_lock, &flock);
2360 if (error)
2361 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002362
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002363 error = check_fmode_for_setlk(file_lock);
2364 if (error)
2365 goto out;
2366
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002367 /*
2368 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002369 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002370 */
2371 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002372 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002373 error = -EINVAL;
2374 if (flock.l_pid != 0)
2375 goto out;
2376
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002377 cmd = F_SETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002378 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002379 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002380 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002381 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002382 error = -EINVAL;
2383 if (flock.l_pid != 0)
2384 goto out;
2385
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002386 cmd = F_SETLKW64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002387 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002388 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002389 /* Fallthrough */
2390 case F_SETLKW64:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002391 file_lock->fl_flags |= FL_SLEEP;
2392 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002393
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002394 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002395
Peter Staubachc2936212005-07-27 11:45:09 -07002396 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002397 * Attempt to detect a close/fcntl race and recover by releasing the
2398 * lock that was just acquired. There is no need to do that when we're
2399 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002400 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002401 if (!error && file_lock->fl_type != F_UNLCK &&
2402 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002403 /*
2404 * We need that spin_lock here - it prevents reordering between
2405 * update of i_flctx->flc_posix and check for it done in
2406 * close(). rcu_read_lock() wouldn't do.
2407 */
2408 spin_lock(&current->files->file_lock);
2409 f = fcheck(fd);
2410 spin_unlock(&current->files->file_lock);
2411 if (f != filp) {
2412 file_lock->fl_type = F_UNLCK;
2413 error = do_lock_file_wait(filp, cmd, file_lock);
2414 WARN_ON_ONCE(error);
2415 error = -EBADF;
2416 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002417 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002418out:
2419 locks_free_lock(file_lock);
2420 return error;
2421}
2422#endif /* BITS_PER_LONG == 32 */
2423
2424/*
2425 * This function is called when the file is being removed
2426 * from the task's fd array. POSIX locks belonging to this task
2427 * are deleted at this time.
2428 */
2429void locks_remove_posix(struct file *filp, fl_owner_t owner)
2430{
Jeff Layton18909102016-01-06 21:26:10 -05002431 int error;
Miklos Szerediff7b86b2006-06-23 02:05:11 -07002432 struct file_lock lock;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002433 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002434
2435 /*
2436 * If there are no locks held on this file, we don't need to call
2437 * posix_lock_file(). Another process could be setting a lock on this
2438 * file at the same time, but we wouldn't remove that lock anyway.
2439 */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002440 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05002441 if (!ctx || list_empty(&ctx->flc_posix))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002442 return;
2443
2444 lock.fl_type = F_UNLCK;
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07002445 lock.fl_flags = FL_POSIX | FL_CLOSE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002446 lock.fl_start = 0;
2447 lock.fl_end = OFFSET_MAX;
2448 lock.fl_owner = owner;
2449 lock.fl_pid = current->tgid;
2450 lock.fl_file = filp;
2451 lock.fl_ops = NULL;
2452 lock.fl_lmops = NULL;
2453
Jeff Layton18909102016-01-06 21:26:10 -05002454 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455
Linus Torvalds1da177e2005-04-16 15:20:36 -07002456 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2457 lock.fl_ops->fl_release_private(&lock);
Jeff Layton18909102016-01-06 21:26:10 -05002458 trace_locks_remove_posix(file_inode(filp), &lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002459}
2460
2461EXPORT_SYMBOL(locks_remove_posix);
2462
Jeff Layton3d8e5602015-01-16 15:05:58 -05002463/* The i_flctx must be valid when calling into here */
Jeff Laytondd459bb2015-01-16 15:05:54 -05002464static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002465locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
Jeff Laytondd459bb2015-01-16 15:05:54 -05002466{
2467 struct file_lock fl = {
2468 .fl_owner = filp,
2469 .fl_pid = current->tgid,
2470 .fl_file = filp,
2471 .fl_flags = FL_FLOCK,
2472 .fl_type = F_UNLCK,
2473 .fl_end = OFFSET_MAX,
2474 };
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002475 struct inode *inode = file_inode(filp);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002476
Jeff Layton3d8e5602015-01-16 15:05:58 -05002477 if (list_empty(&flctx->flc_flock))
Jeff Laytondd459bb2015-01-16 15:05:54 -05002478 return;
2479
2480 if (filp->f_op->flock)
2481 filp->f_op->flock(filp, F_SETLKW, &fl);
2482 else
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002483 flock_lock_inode(inode, &fl);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002484
2485 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2486 fl.fl_ops->fl_release_private(&fl);
2487}
2488
Jeff Layton3d8e5602015-01-16 15:05:58 -05002489/* The i_flctx must be valid when calling into here */
Jeff Layton8634b512015-01-16 15:05:55 -05002490static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002491locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
Jeff Layton8634b512015-01-16 15:05:55 -05002492{
Jeff Layton8634b512015-01-16 15:05:55 -05002493 struct file_lock *fl, *tmp;
2494 LIST_HEAD(dispose);
2495
Jeff Layton3d8e5602015-01-16 15:05:58 -05002496 if (list_empty(&ctx->flc_lease))
Jeff Layton8634b512015-01-16 15:05:55 -05002497 return;
2498
Jeff Layton6109c852015-01-16 15:05:57 -05002499 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002500 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
Jeff Laytonc4e136c2015-02-16 19:37:42 -05002501 if (filp == fl->fl_file)
2502 lease_modify(fl, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05002503 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002504 locks_dispose_list(&dispose);
2505}
2506
Linus Torvalds1da177e2005-04-16 15:20:36 -07002507/*
2508 * This function is called on the last close of an open file.
2509 */
Jeff Layton78ed8a12014-02-03 12:13:08 -05002510void locks_remove_file(struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002511{
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002512 struct file_lock_context *ctx;
2513
2514 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
2515 if (!ctx)
Jeff Layton3d8e5602015-01-16 15:05:58 -05002516 return;
2517
Jeff Laytondd459bb2015-01-16 15:05:54 -05002518 /* remove any OFD locks */
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002519 locks_remove_posix(filp, filp);
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002520
Jeff Laytondd459bb2015-01-16 15:05:54 -05002521 /* remove flock locks */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002522 locks_remove_flock(filp, ctx);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002523
Jeff Layton8634b512015-01-16 15:05:55 -05002524 /* remove any leases */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002525 locks_remove_lease(filp, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002526}
2527
2528/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529 * posix_unblock_lock - stop waiting for a file lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530 * @waiter: the lock which was waiting
2531 *
2532 * lockd needs to block waiting for locks.
2533 */
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002534int
Jeff Laytonf891a292013-06-21 08:58:09 -04002535posix_unblock_lock(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002536{
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002537 int status = 0;
2538
Jeff Layton7b2296a2013-06-21 08:58:20 -04002539 spin_lock(&blocked_lock_lock);
J. Bruce Fields5996a292006-01-03 09:55:44 +01002540 if (waiter->fl_next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002541 __locks_delete_block(waiter);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002542 else
2543 status = -ENOENT;
Jeff Layton7b2296a2013-06-21 08:58:20 -04002544 spin_unlock(&blocked_lock_lock);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002545 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002546}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002547EXPORT_SYMBOL(posix_unblock_lock);
2548
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002549/**
2550 * vfs_cancel_lock - file byte range unblock lock
2551 * @filp: The file to apply the unblock to
2552 * @fl: The lock to be unblocked
2553 *
2554 * Used by lock managers to cancel blocked requests
2555 */
2556int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2557{
Al Viro72c2d532013-09-22 16:27:52 -04002558 if (filp->f_op->lock)
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002559 return filp->f_op->lock(filp, F_CANCELLK, fl);
2560 return 0;
2561}
2562
2563EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2564
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002565#ifdef CONFIG_PROC_FS
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002566#include <linux/proc_fs.h>
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002567#include <linux/seq_file.h>
2568
Jeff Layton7012b022013-06-21 08:58:22 -04002569struct locks_iterator {
2570 int li_cpu;
2571 loff_t li_pos;
2572};
2573
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002574static void lock_get_status(struct seq_file *f, struct file_lock *fl,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002575 loff_t id, char *pfx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002576{
2577 struct inode *inode = NULL;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002578 unsigned int fl_pid;
2579
2580 if (fl->fl_nspid)
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08002581 fl_pid = pid_vnr(fl->fl_nspid);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002582 else
2583 fl_pid = fl->fl_pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002584
2585 if (fl->fl_file != NULL)
Al Viro496ad9a2013-01-23 17:07:38 -05002586 inode = file_inode(fl->fl_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002587
Jerome Marchand99dc8292010-10-26 14:22:33 -07002588 seq_printf(f, "%lld:%s ", id, pfx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002589 if (IS_POSIX(fl)) {
Jeff Laytonc918d422014-02-03 12:13:09 -05002590 if (fl->fl_flags & FL_ACCESS)
Fabian Frederick5315c262014-05-09 14:13:05 -04002591 seq_puts(f, "ACCESS");
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002592 else if (IS_OFDLCK(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002593 seq_puts(f, "OFDLCK");
Jeff Laytonc918d422014-02-03 12:13:09 -05002594 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002595 seq_puts(f, "POSIX ");
Jeff Laytonc918d422014-02-03 12:13:09 -05002596
2597 seq_printf(f, " %s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002598 (inode == NULL) ? "*NOINODE*" :
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002599 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002600 } else if (IS_FLOCK(fl)) {
2601 if (fl->fl_type & LOCK_MAND) {
Fabian Frederick5315c262014-05-09 14:13:05 -04002602 seq_puts(f, "FLOCK MSNFS ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002603 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002604 seq_puts(f, "FLOCK ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002605 }
2606 } else if (IS_LEASE(fl)) {
Jeff Layton8144f1f2014-08-11 13:36:54 -04002607 if (fl->fl_flags & FL_DELEG)
2608 seq_puts(f, "DELEG ");
2609 else
2610 seq_puts(f, "LEASE ");
2611
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002612 if (lease_breaking(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002613 seq_puts(f, "BREAKING ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002614 else if (fl->fl_file)
Fabian Frederick5315c262014-05-09 14:13:05 -04002615 seq_puts(f, "ACTIVE ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002616 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002617 seq_puts(f, "BREAKER ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002618 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002619 seq_puts(f, "UNKNOWN UNKNOWN ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002620 }
2621 if (fl->fl_type & LOCK_MAND) {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002622 seq_printf(f, "%s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002623 (fl->fl_type & LOCK_READ)
2624 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2625 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2626 } else {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002627 seq_printf(f, "%s ",
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002628 (lease_breaking(fl))
Jeff Layton0ee5c6d2012-08-02 15:46:30 -04002629 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2630 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631 }
2632 if (inode) {
Jeff Layton36488882015-04-03 09:04:04 -04002633 /* userspace relies on this representation of dev_t */
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002634 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002635 MAJOR(inode->i_sb->s_dev),
2636 MINOR(inode->i_sb->s_dev), inode->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002637 } else {
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002638 seq_printf(f, "%d <none>:0 ", fl_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002639 }
2640 if (IS_POSIX(fl)) {
2641 if (fl->fl_end == OFFSET_MAX)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002642 seq_printf(f, "%Ld EOF\n", fl->fl_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002643 else
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002644 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002645 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002646 seq_puts(f, "0 EOF\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 }
2648}
2649
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002650static int locks_show(struct seq_file *f, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651{
Jeff Layton7012b022013-06-21 08:58:22 -04002652 struct locks_iterator *iter = f->private;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002653 struct file_lock *fl, *bfl;
2654
Jeff Layton139ca042013-06-21 08:58:17 -04002655 fl = hlist_entry(v, struct file_lock, fl_link);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002656
Jeff Layton7012b022013-06-21 08:58:22 -04002657 lock_get_status(f, fl, iter->li_pos, "");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002658
2659 list_for_each_entry(bfl, &fl->fl_block, fl_block)
Jeff Layton7012b022013-06-21 08:58:22 -04002660 lock_get_status(f, bfl, iter->li_pos, " ->");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002661
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002662 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002663}
2664
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002665static void __show_fd_locks(struct seq_file *f,
2666 struct list_head *head, int *id,
2667 struct file *filp, struct files_struct *files)
2668{
2669 struct file_lock *fl;
2670
2671 list_for_each_entry(fl, head, fl_list) {
2672
2673 if (filp != fl->fl_file)
2674 continue;
2675 if (fl->fl_owner != files &&
2676 fl->fl_owner != filp)
2677 continue;
2678
2679 (*id)++;
2680 seq_puts(f, "lock:\t");
2681 lock_get_status(f, fl, *id, "");
2682 }
2683}
2684
2685void show_fd_locks(struct seq_file *f,
2686 struct file *filp, struct files_struct *files)
2687{
2688 struct inode *inode = file_inode(filp);
2689 struct file_lock_context *ctx;
2690 int id = 0;
2691
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002692 ctx = smp_load_acquire(&inode->i_flctx);
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002693 if (!ctx)
2694 return;
2695
2696 spin_lock(&ctx->flc_lock);
2697 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2698 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2699 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2700 spin_unlock(&ctx->flc_lock);
2701}
2702
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002703static void *locks_start(struct seq_file *f, loff_t *pos)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002704 __acquires(&blocked_lock_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002705{
Jeff Layton7012b022013-06-21 08:58:22 -04002706 struct locks_iterator *iter = f->private;
Jerome Marchand99dc8292010-10-26 14:22:33 -07002707
Jeff Layton7012b022013-06-21 08:58:22 -04002708 iter->li_pos = *pos + 1;
2709 lg_global_lock(&file_lock_lglock);
Jeff Layton7b2296a2013-06-21 08:58:20 -04002710 spin_lock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002711 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002712}
2713
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002714static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2715{
Jeff Layton7012b022013-06-21 08:58:22 -04002716 struct locks_iterator *iter = f->private;
2717
2718 ++iter->li_pos;
2719 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002720}
2721
2722static void locks_stop(struct seq_file *f, void *v)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002723 __releases(&blocked_lock_lock)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002724{
Jeff Layton7b2296a2013-06-21 08:58:20 -04002725 spin_unlock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002726 lg_global_unlock(&file_lock_lglock);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002727}
2728
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002729static const struct seq_operations locks_seq_operations = {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002730 .start = locks_start,
2731 .next = locks_next,
2732 .stop = locks_stop,
2733 .show = locks_show,
2734};
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002735
2736static int locks_open(struct inode *inode, struct file *filp)
2737{
Jeff Layton7012b022013-06-21 08:58:22 -04002738 return seq_open_private(filp, &locks_seq_operations,
2739 sizeof(struct locks_iterator));
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002740}
2741
2742static const struct file_operations proc_locks_operations = {
2743 .open = locks_open,
2744 .read = seq_read,
2745 .llseek = seq_lseek,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002746 .release = seq_release_private,
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002747};
2748
2749static int __init proc_locks_init(void)
2750{
2751 proc_create("locks", 0, NULL, &proc_locks_operations);
2752 return 0;
2753}
Paul Gortmaker91899222015-12-17 14:11:03 -05002754fs_initcall(proc_locks_init);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002755#endif
2756
Linus Torvalds1da177e2005-04-16 15:20:36 -07002757static int __init filelock_init(void)
2758{
Jeff Layton7012b022013-06-21 08:58:22 -04002759 int i;
2760
Jeff Layton4a075e32015-01-16 15:05:54 -05002761 flctx_cache = kmem_cache_create("file_lock_ctx",
2762 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2763
Linus Torvalds1da177e2005-04-16 15:20:36 -07002764 filelock_cache = kmem_cache_create("file_lock_cache",
Miklos Szerediee19cc42011-07-07 13:06:09 +02002765 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2766
Jeff Layton7012b022013-06-21 08:58:22 -04002767 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2768
2769 for_each_possible_cpu(i)
2770 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2771
Linus Torvalds1da177e2005-04-16 15:20:36 -07002772 return 0;
2773}
2774
2775core_initcall(filelock_init);