blob: 1bd71c4d663a8c0356c457905293b5e9e35f2c9a [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Jeff Layton62af4f12014-05-09 14:13:05 -0400131#define CREATE_TRACE_POINTS
132#include <trace/events/filelock.h>
133
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -0800134#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
136#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
137#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
Christoph Hellwig11afe9f2015-01-21 19:17:03 +0100138#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400139#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -0400140#define IS_REMOTELCK(fl) (fl->fl_pid <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Miklos Szeredic568d682016-09-16 12:44:20 +0200142static inline bool is_remote_lock(struct file *filp)
143{
144 return likely(!(filp->f_path.dentry->d_sb->s_flags & MS_NOREMOTELOCK));
145}
146
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400147static bool lease_breaking(struct file_lock *fl)
148{
J. Bruce Fields778fc542011-07-26 18:25:49 -0400149 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
150}
151
152static int target_leasetype(struct file_lock *fl)
153{
154 if (fl->fl_flags & FL_UNLOCK_PENDING)
155 return F_UNLCK;
156 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
157 return F_RDLCK;
158 return fl->fl_type;
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400159}
160
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161int leases_enable = 1;
162int lease_break_time = 45;
163
Jeff Layton1c8c6012013-06-21 08:58:15 -0400164/*
Jeff Layton7012b022013-06-21 08:58:22 -0400165 * The global file_lock_list is only used for displaying /proc/locks, so we
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200166 * keep a list on each CPU, with each list protected by its own spinlock.
167 * Global serialization is done using file_rwsem.
168 *
169 * Note that alterations to the list also require that the relevant flc_lock is
170 * held.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400171 */
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200172struct file_lock_list_struct {
173 spinlock_t lock;
174 struct hlist_head hlist;
175};
176static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
Peter Zijlstraaba37662015-06-22 14:16:33 +0200177DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
Jeff Layton88974692013-06-21 08:58:14 -0400178
Jeff Layton1c8c6012013-06-21 08:58:15 -0400179/*
Jeff Layton48f74182013-06-21 08:58:18 -0400180 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
Jeff Layton7b2296a2013-06-21 08:58:20 -0400181 * It is protected by blocked_lock_lock.
Jeff Layton48f74182013-06-21 08:58:18 -0400182 *
183 * We hash locks by lockowner in order to optimize searching for the lock a
184 * particular lockowner is waiting on.
185 *
186 * FIXME: make this value scale via some heuristic? We generally will want more
187 * buckets when we have more lockowners holding locks, but that's a little
188 * difficult to determine without knowing what the workload will look like.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400189 */
Jeff Layton48f74182013-06-21 08:58:18 -0400190#define BLOCKED_HASH_BITS 7
191static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
Jeff Layton88974692013-06-21 08:58:14 -0400192
Jeff Layton1c8c6012013-06-21 08:58:15 -0400193/*
Jeff Layton7b2296a2013-06-21 08:58:20 -0400194 * This lock protects the blocked_hash. Generally, if you're accessing it, you
195 * want to be holding this lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400196 *
197 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
198 * pointer for file_lock structures that are acting as lock requests (in
199 * contrast to those that are acting as records of acquired locks).
200 *
201 * Note that when we acquire this lock in order to change the above fields,
Jeff Layton6109c852015-01-16 15:05:57 -0500202 * we often hold the flc_lock as well. In certain cases, when reading the fields
Jeff Layton1c8c6012013-06-21 08:58:15 -0400203 * protected by this lock, we can skip acquiring it iff we already hold the
Jeff Layton6109c852015-01-16 15:05:57 -0500204 * flc_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400205 *
206 * In particular, adding an entry to the fl_block list requires that you hold
Jeff Layton6109c852015-01-16 15:05:57 -0500207 * both the flc_lock and the blocked_lock_lock (acquired in that order).
208 * Deleting an entry from the list however only requires the file_lock_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400209 */
Jeff Layton7b2296a2013-06-21 08:58:20 -0400210static DEFINE_SPINLOCK(blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211
Jeff Layton4a075e32015-01-16 15:05:54 -0500212static struct kmem_cache *flctx_cache __read_mostly;
Christoph Lametere18b8902006-12-06 20:33:20 -0800213static struct kmem_cache *filelock_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
Jeff Layton4a075e32015-01-16 15:05:54 -0500215static struct file_lock_context *
Jeff Layton5c1c6692015-04-03 09:04:03 -0400216locks_get_lock_context(struct inode *inode, int type)
Jeff Layton4a075e32015-01-16 15:05:54 -0500217{
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200218 struct file_lock_context *ctx;
Jeff Layton4a075e32015-01-16 15:05:54 -0500219
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200220 /* paired with cmpxchg() below */
221 ctx = smp_load_acquire(&inode->i_flctx);
222 if (likely(ctx) || type == F_UNLCK)
Jeff Layton4a075e32015-01-16 15:05:54 -0500223 goto out;
224
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200225 ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
226 if (!ctx)
Jeff Layton4a075e32015-01-16 15:05:54 -0500227 goto out;
228
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200229 spin_lock_init(&ctx->flc_lock);
230 INIT_LIST_HEAD(&ctx->flc_flock);
231 INIT_LIST_HEAD(&ctx->flc_posix);
232 INIT_LIST_HEAD(&ctx->flc_lease);
Jeff Layton4a075e32015-01-16 15:05:54 -0500233
234 /*
235 * Assign the pointer if it's not already assigned. If it is, then
236 * free the context we just allocated.
237 */
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200238 if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
239 kmem_cache_free(flctx_cache, ctx);
240 ctx = smp_load_acquire(&inode->i_flctx);
241 }
Jeff Layton4a075e32015-01-16 15:05:54 -0500242out:
Jeff Layton18909102016-01-06 21:26:10 -0500243 trace_locks_get_lock_context(inode, type, ctx);
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200244 return ctx;
Jeff Layton4a075e32015-01-16 15:05:54 -0500245}
246
Jeff Laytone24dada2016-01-06 21:28:41 -0500247static void
248locks_dump_ctx_list(struct list_head *list, char *list_type)
249{
250 struct file_lock *fl;
251
252 list_for_each_entry(fl, list, fl_list) {
253 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);
254 }
255}
256
257static void
258locks_check_ctx_lists(struct inode *inode)
259{
260 struct file_lock_context *ctx = inode->i_flctx;
261
262 if (unlikely(!list_empty(&ctx->flc_flock) ||
263 !list_empty(&ctx->flc_posix) ||
264 !list_empty(&ctx->flc_lease))) {
265 pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
266 MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
267 inode->i_ino);
268 locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
269 locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
270 locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
271 }
272}
273
Benjamin Coddington39537042017-07-21 13:36:25 -0400274static void
275locks_check_ctx_file_list(struct file *filp, struct list_head *list,
276 char *list_type)
277{
278 struct file_lock *fl;
279 struct inode *inode = locks_inode(filp);
280
281 list_for_each_entry(fl, list, fl_list)
282 if (fl->fl_file == filp)
283 pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%lx "
284 " fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
285 list_type, MAJOR(inode->i_sb->s_dev),
286 MINOR(inode->i_sb->s_dev), inode->i_ino,
287 fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
288}
289
Jeff Layton4a075e32015-01-16 15:05:54 -0500290void
Jeff Laytonf27a0fe2016-01-07 15:08:51 -0500291locks_free_lock_context(struct inode *inode)
Jeff Layton4a075e32015-01-16 15:05:54 -0500292{
Jeff Laytonf27a0fe2016-01-07 15:08:51 -0500293 struct file_lock_context *ctx = inode->i_flctx;
294
Jeff Laytone24dada2016-01-06 21:28:41 -0500295 if (unlikely(ctx)) {
296 locks_check_ctx_lists(inode);
Jeff Layton4a075e32015-01-16 15:05:54 -0500297 kmem_cache_free(flctx_cache, ctx);
298 }
299}
300
Miklos Szerediee19cc42011-07-07 13:06:09 +0200301static void locks_init_lock_heads(struct file_lock *fl)
Miklos Szeredia51cb912011-07-06 12:33:55 +0200302{
Jeff Layton139ca042013-06-21 08:58:17 -0400303 INIT_HLIST_NODE(&fl->fl_link);
Jeff Layton6dee60f2015-01-16 15:05:54 -0500304 INIT_LIST_HEAD(&fl->fl_list);
Miklos Szerediee19cc42011-07-07 13:06:09 +0200305 INIT_LIST_HEAD(&fl->fl_block);
306 init_waitqueue_head(&fl->fl_wait);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200307}
308
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309/* Allocate an empty lock structure. */
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200310struct file_lock *locks_alloc_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200312 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200313
314 if (fl)
Miklos Szerediee19cc42011-07-07 13:06:09 +0200315 locks_init_lock_heads(fl);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200316
317 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318}
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200319EXPORT_SYMBOL_GPL(locks_alloc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500321void locks_release_private(struct file_lock *fl)
Trond Myklebust47831f32006-03-20 13:44:05 -0500322{
323 if (fl->fl_ops) {
324 if (fl->fl_ops->fl_release_private)
325 fl->fl_ops->fl_release_private(fl);
326 fl->fl_ops = NULL;
327 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500328
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400329 if (fl->fl_lmops) {
Jeff Laytoncae80b32015-04-03 09:04:04 -0400330 if (fl->fl_lmops->lm_put_owner) {
331 fl->fl_lmops->lm_put_owner(fl->fl_owner);
332 fl->fl_owner = NULL;
333 }
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400334 fl->fl_lmops = NULL;
335 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500336}
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500337EXPORT_SYMBOL_GPL(locks_release_private);
Trond Myklebust47831f32006-03-20 13:44:05 -0500338
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339/* Free a lock which is not in use. */
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400340void locks_free_lock(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341{
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800342 BUG_ON(waitqueue_active(&fl->fl_wait));
Jeff Layton6dee60f2015-01-16 15:05:54 -0500343 BUG_ON(!list_empty(&fl->fl_list));
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800344 BUG_ON(!list_empty(&fl->fl_block));
Jeff Layton139ca042013-06-21 08:58:17 -0400345 BUG_ON(!hlist_unhashed(&fl->fl_link));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
Trond Myklebust47831f32006-03-20 13:44:05 -0500347 locks_release_private(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 kmem_cache_free(filelock_cache, fl);
349}
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400350EXPORT_SYMBOL(locks_free_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
Jeff Laytoned9814d2014-08-11 14:20:31 -0400352static void
353locks_dispose_list(struct list_head *dispose)
354{
355 struct file_lock *fl;
356
357 while (!list_empty(dispose)) {
Jeff Layton6dee60f2015-01-16 15:05:54 -0500358 fl = list_first_entry(dispose, struct file_lock, fl_list);
359 list_del_init(&fl->fl_list);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400360 locks_free_lock(fl);
361 }
362}
363
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364void locks_init_lock(struct file_lock *fl)
365{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200366 memset(fl, 0, sizeof(struct file_lock));
367 locks_init_lock_heads(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368}
369
370EXPORT_SYMBOL(locks_init_lock);
371
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372/*
373 * Initialize a new lock from an existing file_lock structure.
374 */
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400375void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376{
377 new->fl_owner = fl->fl_owner;
378 new->fl_pid = fl->fl_pid;
Trond Myklebust09969052006-03-20 13:44:38 -0500379 new->fl_file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 new->fl_flags = fl->fl_flags;
381 new->fl_type = fl->fl_type;
382 new->fl_start = fl->fl_start;
383 new->fl_end = fl->fl_end;
Kinglong Meef3282962014-08-22 10:18:43 -0400384 new->fl_lmops = fl->fl_lmops;
Trond Myklebust09969052006-03-20 13:44:38 -0500385 new->fl_ops = NULL;
Kinglong Meef3282962014-08-22 10:18:43 -0400386
387 if (fl->fl_lmops) {
388 if (fl->fl_lmops->lm_get_owner)
Jeff Laytoncae80b32015-04-03 09:04:04 -0400389 fl->fl_lmops->lm_get_owner(fl->fl_owner);
Kinglong Meef3282962014-08-22 10:18:43 -0400390 }
Trond Myklebust09969052006-03-20 13:44:38 -0500391}
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400392EXPORT_SYMBOL(locks_copy_conflock);
Trond Myklebust09969052006-03-20 13:44:38 -0500393
394void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
395{
Jeff Layton566709b2014-08-11 14:09:35 -0400396 /* "new" must be a freshly-initialized lock */
397 WARN_ON_ONCE(new->fl_ops);
Trond Myklebust09969052006-03-20 13:44:38 -0500398
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400399 locks_copy_conflock(new, fl);
Kinglong Meef3282962014-08-22 10:18:43 -0400400
Trond Myklebust09969052006-03-20 13:44:38 -0500401 new->fl_file = fl->fl_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 new->fl_ops = fl->fl_ops;
Trond Myklebust47831f32006-03-20 13:44:05 -0500403
Kinglong Meef3282962014-08-22 10:18:43 -0400404 if (fl->fl_ops) {
405 if (fl->fl_ops->fl_copy_lock)
406 fl->fl_ops->fl_copy_lock(new, fl);
407 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408}
409
410EXPORT_SYMBOL(locks_copy_lock);
411
412static inline int flock_translate_cmd(int cmd) {
413 if (cmd & LOCK_MAND)
414 return cmd & (LOCK_MAND | LOCK_RW);
415 switch (cmd) {
416 case LOCK_SH:
417 return F_RDLCK;
418 case LOCK_EX:
419 return F_WRLCK;
420 case LOCK_UN:
421 return F_UNLCK;
422 }
423 return -EINVAL;
424}
425
426/* Fill in a file_lock structure with an appropriate FLOCK lock. */
Jeff Layton6e129d002014-09-04 10:25:06 -0400427static struct file_lock *
428flock_make_lock(struct file *filp, unsigned int cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429{
430 struct file_lock *fl;
431 int type = flock_translate_cmd(cmd);
Jeff Layton6e129d002014-09-04 10:25:06 -0400432
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 if (type < 0)
Jeff Layton6e129d002014-09-04 10:25:06 -0400434 return ERR_PTR(type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
436 fl = locks_alloc_lock();
437 if (fl == NULL)
Jeff Layton6e129d002014-09-04 10:25:06 -0400438 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
440 fl->fl_file = filp;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +0200441 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 fl->fl_pid = current->tgid;
443 fl->fl_flags = FL_FLOCK;
444 fl->fl_type = type;
445 fl->fl_end = OFFSET_MAX;
446
Jeff Layton6e129d002014-09-04 10:25:06 -0400447 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448}
449
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400450static int assign_type(struct file_lock *fl, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451{
452 switch (type) {
453 case F_RDLCK:
454 case F_WRLCK:
455 case F_UNLCK:
456 fl->fl_type = type;
457 break;
458 default:
459 return -EINVAL;
460 }
461 return 0;
462}
463
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500464static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
465 struct flock64 *l)
466{
467 switch (l->l_whence) {
468 case SEEK_SET:
469 fl->fl_start = 0;
470 break;
471 case SEEK_CUR:
472 fl->fl_start = filp->f_pos;
473 break;
474 case SEEK_END:
475 fl->fl_start = i_size_read(file_inode(filp));
476 break;
477 default:
478 return -EINVAL;
479 }
480 if (l->l_start > OFFSET_MAX - fl->fl_start)
481 return -EOVERFLOW;
482 fl->fl_start += l->l_start;
483 if (fl->fl_start < 0)
484 return -EINVAL;
485
486 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
487 POSIX-2001 defines it. */
488 if (l->l_len > 0) {
489 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
490 return -EOVERFLOW;
491 fl->fl_end = fl->fl_start + l->l_len - 1;
492
493 } else if (l->l_len < 0) {
494 if (fl->fl_start + l->l_len < 0)
495 return -EINVAL;
496 fl->fl_end = fl->fl_start - 1;
497 fl->fl_start += l->l_len;
498 } else
499 fl->fl_end = OFFSET_MAX;
500
501 fl->fl_owner = current->files;
502 fl->fl_pid = current->tgid;
503 fl->fl_file = filp;
504 fl->fl_flags = FL_POSIX;
505 fl->fl_ops = NULL;
506 fl->fl_lmops = NULL;
507
508 return assign_type(fl, l->l_type);
509}
510
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
512 * style lock.
513 */
514static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
515 struct flock *l)
516{
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500517 struct flock64 ll = {
518 .l_type = l->l_type,
519 .l_whence = l->l_whence,
520 .l_start = l->l_start,
521 .l_len = l->l_len,
522 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500524 return flock64_to_posix_lock(filp, fl, &ll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525}
526
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527/* default lease lock manager operations */
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400528static bool
529lease_break_callback(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530{
531 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400532 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533}
534
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400535static void
536lease_setup(struct file_lock *fl, void **priv)
537{
538 struct file *filp = fl->fl_file;
539 struct fasync_struct *fa = *priv;
540
541 /*
542 * fasync_insert_entry() returns the old entry if any. If there was no
543 * old entry, then it used "priv" and inserted it into the fasync list.
544 * Clear the pointer to indicate that it shouldn't be freed.
545 */
546 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
547 *priv = NULL;
548
549 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
550}
551
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700552static const struct lock_manager_operations lease_manager_ops = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400553 .lm_break = lease_break_callback,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400554 .lm_change = lease_modify,
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400555 .lm_setup = lease_setup,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556};
557
558/*
559 * Initialize a lease, use the default lock manager operations
560 */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400561static int lease_init(struct file *filp, long type, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 {
Trond Myklebust75dff552006-05-07 23:02:42 -0400563 if (assign_type(fl, type) != 0)
564 return -EINVAL;
565
Jeff Layton7ca76312014-09-01 19:04:48 -0400566 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 fl->fl_pid = current->tgid;
568
569 fl->fl_file = filp;
570 fl->fl_flags = FL_LEASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 fl->fl_start = 0;
572 fl->fl_end = OFFSET_MAX;
573 fl->fl_ops = NULL;
574 fl->fl_lmops = &lease_manager_ops;
575 return 0;
576}
577
578/* Allocate a file_lock initialised to this type of lease */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400579static struct file_lock *lease_alloc(struct file *filp, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580{
581 struct file_lock *fl = locks_alloc_lock();
Trond Myklebust75dff552006-05-07 23:02:42 -0400582 int error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583
584 if (fl == NULL)
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500585 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
587 error = lease_init(filp, type, fl);
Trond Myklebust75dff552006-05-07 23:02:42 -0400588 if (error) {
589 locks_free_lock(fl);
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500590 return ERR_PTR(error);
Trond Myklebust75dff552006-05-07 23:02:42 -0400591 }
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500592 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593}
594
595/* Check if two locks overlap each other.
596 */
597static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
598{
599 return ((fl1->fl_end >= fl2->fl_start) &&
600 (fl2->fl_end >= fl1->fl_start));
601}
602
603/*
604 * Check whether two locks have the same owner.
605 */
Matt Mackall33443c42006-01-08 01:05:22 -0800606static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607{
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400608 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 return fl2->fl_lmops == fl1->fl_lmops &&
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400610 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 return fl1->fl_owner == fl2->fl_owner;
612}
613
Jeff Layton6109c852015-01-16 15:05:57 -0500614/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500615static void locks_insert_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400616{
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200617 struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
618
Peter Zijlstraaba37662015-06-22 14:16:33 +0200619 percpu_rwsem_assert_held(&file_rwsem);
620
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200621 spin_lock(&fll->lock);
Jeff Layton7012b022013-06-21 08:58:22 -0400622 fl->fl_link_cpu = smp_processor_id();
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200623 hlist_add_head(&fl->fl_link, &fll->hlist);
624 spin_unlock(&fll->lock);
Jeff Layton88974692013-06-21 08:58:14 -0400625}
626
Jeff Layton6109c852015-01-16 15:05:57 -0500627/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500628static void locks_delete_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400629{
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200630 struct file_lock_list_struct *fll;
631
Peter Zijlstraaba37662015-06-22 14:16:33 +0200632 percpu_rwsem_assert_held(&file_rwsem);
633
Jeff Layton7012b022013-06-21 08:58:22 -0400634 /*
635 * Avoid taking lock if already unhashed. This is safe since this check
Jeff Layton6109c852015-01-16 15:05:57 -0500636 * is done while holding the flc_lock, and new insertions into the list
Jeff Layton7012b022013-06-21 08:58:22 -0400637 * also require that it be held.
638 */
639 if (hlist_unhashed(&fl->fl_link))
640 return;
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200641
642 fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
643 spin_lock(&fll->lock);
Jeff Layton139ca042013-06-21 08:58:17 -0400644 hlist_del_init(&fl->fl_link);
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200645 spin_unlock(&fll->lock);
Jeff Layton88974692013-06-21 08:58:14 -0400646}
647
Jeff Layton3999e492013-06-21 08:58:19 -0400648static unsigned long
649posix_owner_key(struct file_lock *fl)
650{
651 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
652 return fl->fl_lmops->lm_owner_key(fl);
653 return (unsigned long)fl->fl_owner;
654}
655
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500656static void locks_insert_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400657{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400658 lockdep_assert_held(&blocked_lock_lock);
659
Jeff Layton3999e492013-06-21 08:58:19 -0400660 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
Jeff Layton88974692013-06-21 08:58:14 -0400661}
662
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500663static void locks_delete_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400664{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400665 lockdep_assert_held(&blocked_lock_lock);
666
Jeff Layton48f74182013-06-21 08:58:18 -0400667 hash_del(&waiter->fl_link);
Jeff Layton88974692013-06-21 08:58:14 -0400668}
669
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670/* Remove waiter from blocker's block list.
671 * When blocker ends up pointing to itself then the list is empty.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400672 *
Jeff Layton7b2296a2013-06-21 08:58:20 -0400673 * Must be called with blocked_lock_lock held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 */
Matt Mackall33443c42006-01-08 01:05:22 -0800675static void __locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676{
Jeff Layton88974692013-06-21 08:58:14 -0400677 locks_delete_global_blocked(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 list_del_init(&waiter->fl_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 waiter->fl_next = NULL;
680}
681
Jeff Layton1a9e64a2013-06-21 08:58:10 -0400682static void locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400684 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 __locks_delete_block(waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400686 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687}
688
689/* Insert waiter into blocker's block list.
690 * We use a circular list so that processes can be easily woken up in
691 * the order they blocked. The documentation doesn't require this but
692 * it seems like the reasonable thing to do.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400693 *
Jeff Layton6109c852015-01-16 15:05:57 -0500694 * Must be called with both the flc_lock and blocked_lock_lock held. The
695 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
696 * that the flc_lock is also held on insertions we can avoid taking the
697 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400699static void __locks_insert_block(struct file_lock *blocker,
700 struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701{
J. Bruce Fields6dc0fe82006-03-26 01:37:24 -0800702 BUG_ON(!list_empty(&waiter->fl_block));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 waiter->fl_next = blocker;
Jeff Layton88974692013-06-21 08:58:14 -0400704 list_add_tail(&waiter->fl_block, &blocker->fl_block);
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400705 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
Jeff Layton1c8c6012013-06-21 08:58:15 -0400706 locks_insert_global_blocked(waiter);
707}
708
Jeff Layton6109c852015-01-16 15:05:57 -0500709/* Must be called with flc_lock held. */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400710static void locks_insert_block(struct file_lock *blocker,
711 struct file_lock *waiter)
712{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400713 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400714 __locks_insert_block(blocker, waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400715 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716}
717
Jeff Layton1cb36012013-06-21 08:58:12 -0400718/*
719 * Wake up processes blocked waiting for blocker.
720 *
Jeff Layton6109c852015-01-16 15:05:57 -0500721 * Must be called with the inode->flc_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 */
723static void locks_wake_up_blocks(struct file_lock *blocker)
724{
Jeff Layton4e8c7652013-06-21 08:58:16 -0400725 /*
726 * Avoid taking global lock if list is empty. This is safe since new
Jeff Layton6109c852015-01-16 15:05:57 -0500727 * blocked requests are only added to the list under the flc_lock, and
728 * the flc_lock is always held here. Note that removal from the fl_block
729 * list does not require the flc_lock, so we must recheck list_empty()
Jeff Layton7b2296a2013-06-21 08:58:20 -0400730 * after acquiring the blocked_lock_lock.
Jeff Layton4e8c7652013-06-21 08:58:16 -0400731 */
732 if (list_empty(&blocker->fl_block))
733 return;
734
Jeff Layton7b2296a2013-06-21 08:58:20 -0400735 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 while (!list_empty(&blocker->fl_block)) {
Pavel Emelyanovf0c1cd02007-09-19 16:44:07 +0400737 struct file_lock *waiter;
738
739 waiter = list_first_entry(&blocker->fl_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 struct file_lock, fl_block);
741 __locks_delete_block(waiter);
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400742 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
743 waiter->fl_lmops->lm_notify(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 else
745 wake_up(&waiter->fl_wait);
746 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400747 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748}
749
Jeff Layton5263e312015-01-16 15:05:55 -0500750static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500751locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
Jeff Layton5263e312015-01-16 15:05:55 -0500752{
Jeff Layton5263e312015-01-16 15:05:55 -0500753 list_add_tail(&fl->fl_list, before);
754 locks_insert_global_locks(fl);
755}
756
Jeff Layton8634b512015-01-16 15:05:55 -0500757static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500758locks_unlink_lock_ctx(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759{
Jeff Layton88974692013-06-21 08:58:14 -0400760 locks_delete_global_locks(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500761 list_del_init(&fl->fl_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 locks_wake_up_blocks(fl);
Jeff Layton24cbe782014-02-03 12:13:06 -0500763}
764
Jeff Layton5263e312015-01-16 15:05:55 -0500765static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500766locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
Jeff Layton5263e312015-01-16 15:05:55 -0500767{
Jeff Laytone084c1b2015-02-16 14:32:03 -0500768 locks_unlink_lock_ctx(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500769 if (dispose)
770 list_add(&fl->fl_list, dispose);
771 else
772 locks_free_lock(fl);
Jeff Layton5263e312015-01-16 15:05:55 -0500773}
774
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
776 * checks for shared/exclusive status of overlapping locks.
777 */
778static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
779{
780 if (sys_fl->fl_type == F_WRLCK)
781 return 1;
782 if (caller_fl->fl_type == F_WRLCK)
783 return 1;
784 return 0;
785}
786
787/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
788 * checking before calling the locks_conflict().
789 */
790static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
791{
792 /* POSIX locks owned by the same process do not conflict with
793 * each other.
794 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400795 if (posix_same_owner(caller_fl, sys_fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 return (0);
797
798 /* Check whether they overlap */
799 if (!locks_overlap(caller_fl, sys_fl))
800 return 0;
801
802 return (locks_conflict(caller_fl, sys_fl));
803}
804
805/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
806 * checking before calling the locks_conflict().
807 */
808static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
809{
810 /* FLOCK locks referring to the same filp do not conflict with
811 * each other.
812 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400813 if (caller_fl->fl_file == sys_fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 return (0);
815 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
816 return 0;
817
818 return (locks_conflict(caller_fl, sys_fl));
819}
820
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400821void
Marc Eshel9d6a8c52007-02-21 00:55:18 -0500822posix_test_lock(struct file *filp, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823{
824 struct file_lock *cfl;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500825 struct file_lock_context *ctx;
Miklos Szeredic568d682016-09-16 12:44:20 +0200826 struct inode *inode = locks_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200828 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500829 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
J. Bruce Fields129a84d2007-05-10 18:38:43 -0400830 fl->fl_type = F_UNLCK;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500831 return;
832 }
833
Jeff Layton6109c852015-01-16 15:05:57 -0500834 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500835 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
836 if (posix_locks_conflict(fl, cfl)) {
837 locks_copy_conflock(fl, cfl);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500838 goto out;
839 }
840 }
841 fl->fl_type = F_UNLCK;
842out:
Jeff Layton6109c852015-01-16 15:05:57 -0500843 spin_unlock(&ctx->flc_lock);
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400844 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846EXPORT_SYMBOL(posix_test_lock);
847
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400848/*
849 * Deadlock detection:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400851 * We attempt to detect deadlocks that are due purely to posix file
852 * locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400854 * We assume that a task can be waiting for at most one lock at a time.
855 * So for any acquired lock, the process holding that lock may be
856 * waiting on at most one other lock. That lock in turns may be held by
857 * someone waiting for at most one other lock. Given a requested lock
858 * caller_fl which is about to wait for a conflicting lock block_fl, we
859 * follow this chain of waiters to ensure we are not about to create a
860 * cycle.
J. Bruce Fields97855b42007-10-30 11:20:02 -0400861 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400862 * Since we do this before we ever put a process to sleep on a lock, we
863 * are ensured that there is never a cycle; that is what guarantees that
864 * the while() loop in posix_locks_deadlock() eventually completes.
865 *
866 * Note: the above assumption may not be true when handling lock
867 * requests from a broken NFS client. It may also fail in the presence
868 * of tasks (such as posix threads) sharing the same open file table.
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400869 * To handle those cases, we just bail out after a few iterations.
Jeff Layton57b65322014-02-03 12:13:09 -0500870 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400871 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
Jeff Layton57b65322014-02-03 12:13:09 -0500872 * Because the owner is not even nominally tied to a thread of
873 * execution, the deadlock detection below can't reasonably work well. Just
874 * skip it for those.
875 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400876 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
Jeff Layton57b65322014-02-03 12:13:09 -0500877 * locks that just checks for the case where two tasks are attempting to
878 * upgrade from read to write locks on the same inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 */
J. Bruce Fields97855b42007-10-30 11:20:02 -0400880
881#define MAX_DEADLK_ITERATIONS 10
882
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400883/* Find a lock that the owner of the given block_fl is blocking on. */
884static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
885{
886 struct file_lock *fl;
887
Jeff Layton3999e492013-06-21 08:58:19 -0400888 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400889 if (posix_same_owner(fl, block_fl))
890 return fl->fl_next;
891 }
892 return NULL;
893}
894
Jeff Layton7b2296a2013-06-21 08:58:20 -0400895/* Must be called with the blocked_lock_lock held! */
Adrian Bunkb0904e12006-06-23 02:05:13 -0700896static int posix_locks_deadlock(struct file_lock *caller_fl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 struct file_lock *block_fl)
898{
J. Bruce Fields97855b42007-10-30 11:20:02 -0400899 int i = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900
Daniel Wagner663d5af2015-04-03 09:04:03 -0400901 lockdep_assert_held(&blocked_lock_lock);
902
Jeff Layton57b65322014-02-03 12:13:09 -0500903 /*
904 * This deadlock detector can't reasonably detect deadlocks with
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400905 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
Jeff Layton57b65322014-02-03 12:13:09 -0500906 */
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400907 if (IS_OFDLCK(caller_fl))
Jeff Layton57b65322014-02-03 12:13:09 -0500908 return 0;
909
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400910 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
911 if (i++ > MAX_DEADLK_ITERATIONS)
912 return 0;
913 if (posix_same_owner(caller_fl, block_fl))
914 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 }
916 return 0;
917}
918
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
J. Bruce Fields02888f42007-09-12 15:45:07 -0400920 * after any leases, but before any posix locks.
Trond Myklebustf475ae92006-06-29 16:38:32 -0400921 *
922 * Note that if called with an FL_EXISTS argument, the caller may determine
923 * whether or not a lock was successfully freed by testing the return
924 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 */
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400926static int flock_lock_inode(struct inode *inode, struct file_lock *request)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927{
Trond Myklebust993dfa82006-03-31 02:30:55 -0800928 struct file_lock *new_fl = NULL;
Jeff Layton5263e312015-01-16 15:05:55 -0500929 struct file_lock *fl;
930 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 int error = 0;
Jeff Layton5263e312015-01-16 15:05:55 -0500932 bool found = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400933 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934
Jeff Layton5c1c6692015-04-03 09:04:03 -0400935 ctx = locks_get_lock_context(inode, request->fl_type);
936 if (!ctx) {
937 if (request->fl_type != F_UNLCK)
938 return -ENOMEM;
939 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
940 }
Jeff Layton5263e312015-01-16 15:05:55 -0500941
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200942 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
943 new_fl = locks_alloc_lock();
944 if (!new_fl)
945 return -ENOMEM;
946 }
947
Peter Zijlstra87709e22016-05-30 16:48:35 +0200948 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -0500949 spin_lock(&ctx->flc_lock);
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400950 if (request->fl_flags & FL_ACCESS)
951 goto find_conflict;
Pavel Emelyanov84d535a2007-09-11 16:38:13 +0400952
Jeff Layton5263e312015-01-16 15:05:55 -0500953 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400954 if (request->fl_file != fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 continue;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800956 if (request->fl_type == fl->fl_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 goto out;
Jeff Layton5263e312015-01-16 15:05:55 -0500958 found = true;
Jeff Laytone084c1b2015-02-16 14:32:03 -0500959 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 break;
961 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962
Trond Myklebustf475ae92006-06-29 16:38:32 -0400963 if (request->fl_type == F_UNLCK) {
964 if ((request->fl_flags & FL_EXISTS) && !found)
965 error = -ENOENT;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800966 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -0400967 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400969find_conflict:
Jeff Layton5263e312015-01-16 15:05:55 -0500970 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Trond Myklebust993dfa82006-03-31 02:30:55 -0800971 if (!flock_locks_conflict(request, fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 continue;
973 error = -EAGAIN;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700974 if (!(request->fl_flags & FL_SLEEP))
975 goto out;
976 error = FILE_LOCK_DEFERRED;
977 locks_insert_block(fl, request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 goto out;
979 }
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400980 if (request->fl_flags & FL_ACCESS)
981 goto out;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800982 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -0500983 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800984 new_fl = NULL;
Kirill Korotaev9cedc192006-06-14 17:59:35 +0400985 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986
987out:
Jeff Layton6109c852015-01-16 15:05:57 -0500988 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +0200989 percpu_up_read_preempt_enable(&file_rwsem);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800990 if (new_fl)
991 locks_free_lock(new_fl);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400992 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 return error;
994}
995
Jeff Laytonb4d629a2016-01-07 18:27:42 -0500996static int posix_lock_inode(struct inode *inode, struct file_lock *request,
997 struct file_lock *conflock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500999 struct file_lock *fl, *tmp;
Miklos Szeredi39005d02006-06-23 02:05:10 -07001000 struct file_lock *new_fl = NULL;
1001 struct file_lock *new_fl2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 struct file_lock *left = NULL;
1003 struct file_lock *right = NULL;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001004 struct file_lock_context *ctx;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001005 int error;
1006 bool added = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -04001007 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008
Jeff Layton5c1c6692015-04-03 09:04:03 -04001009 ctx = locks_get_lock_context(inode, request->fl_type);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001010 if (!ctx)
Jeff Layton5c1c6692015-04-03 09:04:03 -04001011 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001012
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 /*
1014 * We may need two file_lock structures for this operation,
1015 * so we get them in advance to avoid races.
Miklos Szeredi39005d02006-06-23 02:05:10 -07001016 *
1017 * In some cases we can be sure, that no new locks will be needed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 */
Miklos Szeredi39005d02006-06-23 02:05:10 -07001019 if (!(request->fl_flags & FL_ACCESS) &&
1020 (request->fl_type != F_UNLCK ||
1021 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1022 new_fl = locks_alloc_lock();
1023 new_fl2 = locks_alloc_lock();
1024 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025
Peter Zijlstra87709e22016-05-30 16:48:35 +02001026 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001027 spin_lock(&ctx->flc_lock);
Jeff Layton1cb36012013-06-21 08:58:12 -04001028 /*
1029 * New lock request. Walk all POSIX locks and look for conflicts. If
1030 * there are any, either return error or put the request on the
Jeff Layton48f74182013-06-21 08:58:18 -04001031 * blocker's list of waiters and the global blocked_hash.
Jeff Layton1cb36012013-06-21 08:58:12 -04001032 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 if (request->fl_type != F_UNLCK) {
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001034 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 if (!posix_locks_conflict(request, fl))
1036 continue;
Andy Adamson5842add2006-03-26 01:37:26 -08001037 if (conflock)
Kinglong Mee3fe0fff12014-08-22 10:18:42 -04001038 locks_copy_conflock(conflock, fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 error = -EAGAIN;
1040 if (!(request->fl_flags & FL_SLEEP))
1041 goto out;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001042 /*
1043 * Deadlock detection and insertion into the blocked
1044 * locks list must be done while holding the same lock!
1045 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 error = -EDEADLK;
Jeff Layton7b2296a2013-06-21 08:58:20 -04001047 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001048 if (likely(!posix_locks_deadlock(request, fl))) {
1049 error = FILE_LOCK_DEFERRED;
1050 __locks_insert_block(fl, request);
1051 }
Jeff Layton7b2296a2013-06-21 08:58:20 -04001052 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053 goto out;
1054 }
1055 }
1056
1057 /* If we're just looking for a conflict, we're done. */
1058 error = 0;
1059 if (request->fl_flags & FL_ACCESS)
1060 goto out;
1061
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001062 /* Find the first old lock with the same owner as the new lock */
1063 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1064 if (posix_same_owner(request, fl))
1065 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 }
1067
Jeff Layton1cb36012013-06-21 08:58:12 -04001068 /* Process locks with this owner. */
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001069 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1070 if (!posix_same_owner(request, fl))
1071 break;
1072
1073 /* Detect adjacent or overlapping regions (if same lock type) */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 if (request->fl_type == fl->fl_type) {
Olaf Kirch449231d2005-08-25 16:25:35 -07001075 /* In all comparisons of start vs end, use
1076 * "start - 1" rather than "end + 1". If end
1077 * is OFFSET_MAX, end + 1 will become negative.
1078 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 if (fl->fl_end < request->fl_start - 1)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001080 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 /* If the next lock in the list has entirely bigger
1082 * addresses than the new one, insert the lock here.
1083 */
Olaf Kirch449231d2005-08-25 16:25:35 -07001084 if (fl->fl_start - 1 > request->fl_end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 break;
1086
1087 /* If we come here, the new and old lock are of the
1088 * same type and adjacent or overlapping. Make one
1089 * lock yielding from the lower start address of both
1090 * locks to the higher end address.
1091 */
1092 if (fl->fl_start > request->fl_start)
1093 fl->fl_start = request->fl_start;
1094 else
1095 request->fl_start = fl->fl_start;
1096 if (fl->fl_end < request->fl_end)
1097 fl->fl_end = request->fl_end;
1098 else
1099 request->fl_end = fl->fl_end;
1100 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001101 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 continue;
1103 }
1104 request = fl;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001105 added = true;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001106 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 /* Processing for different lock types is a bit
1108 * more complex.
1109 */
1110 if (fl->fl_end < request->fl_start)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001111 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 if (fl->fl_start > request->fl_end)
1113 break;
1114 if (request->fl_type == F_UNLCK)
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001115 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 if (fl->fl_start < request->fl_start)
1117 left = fl;
1118 /* If the next lock in the list has a higher end
1119 * address than the new one, insert the new one here.
1120 */
1121 if (fl->fl_end > request->fl_end) {
1122 right = fl;
1123 break;
1124 }
1125 if (fl->fl_start >= request->fl_start) {
1126 /* The new lock completely replaces an old
1127 * one (This may happen several times).
1128 */
1129 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001130 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 continue;
1132 }
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001133 /*
1134 * Replace the old lock with new_fl, and
1135 * remove the old one. It's safe to do the
1136 * insert here since we know that we won't be
1137 * using new_fl later, and that the lock is
1138 * just replacing an existing lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 */
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001140 error = -ENOLCK;
1141 if (!new_fl)
1142 goto out;
1143 locks_copy_lock(new_fl, request);
1144 request = new_fl;
1145 new_fl = NULL;
Jeff Laytone084c1b2015-02-16 14:32:03 -05001146 locks_insert_lock_ctx(request, &fl->fl_list);
1147 locks_delete_lock_ctx(fl, &dispose);
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001148 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 }
1150 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 }
1152
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001153 /*
Jeff Layton1cb36012013-06-21 08:58:12 -04001154 * The above code only modifies existing locks in case of merging or
1155 * replacing. If new lock(s) need to be inserted all modifications are
1156 * done below this, so it's safe yet to bail out.
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001157 */
1158 error = -ENOLCK; /* "no luck" */
1159 if (right && left == right && !new_fl2)
1160 goto out;
1161
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 error = 0;
1163 if (!added) {
Trond Myklebustf475ae92006-06-29 16:38:32 -04001164 if (request->fl_type == F_UNLCK) {
1165 if (request->fl_flags & FL_EXISTS)
1166 error = -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -04001168 }
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001169
1170 if (!new_fl) {
1171 error = -ENOLCK;
1172 goto out;
1173 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001175 locks_insert_lock_ctx(new_fl, &fl->fl_list);
Jeff Layton2e2f756f2015-02-17 17:08:23 -05001176 fl = new_fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 new_fl = NULL;
1178 }
1179 if (right) {
1180 if (left == right) {
1181 /* The new lock breaks the old one in two pieces,
1182 * so we have to use the second new lock.
1183 */
1184 left = new_fl2;
1185 new_fl2 = NULL;
1186 locks_copy_lock(left, right);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001187 locks_insert_lock_ctx(left, &fl->fl_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 }
1189 right->fl_start = request->fl_end + 1;
1190 locks_wake_up_blocks(right);
1191 }
1192 if (left) {
1193 left->fl_end = request->fl_start - 1;
1194 locks_wake_up_blocks(left);
1195 }
1196 out:
Jeff Layton6109c852015-01-16 15:05:57 -05001197 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001198 percpu_up_read_preempt_enable(&file_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 /*
1200 * Free any unused locks.
1201 */
1202 if (new_fl)
1203 locks_free_lock(new_fl);
1204 if (new_fl2)
1205 locks_free_lock(new_fl2);
Jeff Laytoned9814d2014-08-11 14:20:31 -04001206 locks_dispose_list(&dispose);
Jeff Layton18909102016-01-06 21:26:10 -05001207 trace_posix_lock_inode(inode, request, error);
1208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 return error;
1210}
1211
1212/**
1213 * posix_lock_file - Apply a POSIX-style lock to a file
1214 * @filp: The file to apply the lock to
1215 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05001216 * @conflock: Place to return a copy of the conflicting lock, if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 *
1218 * Add a POSIX style lock to a file.
1219 * We merge adjacent & overlapping locks whenever possible.
1220 * POSIX locks are sorted by owner task, then by starting address
Trond Myklebustf475ae92006-06-29 16:38:32 -04001221 *
1222 * Note that if called with an FL_EXISTS argument, the caller may determine
1223 * whether or not a lock was successfully freed by testing the return
1224 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 */
Marc Eshel150b3932007-01-18 16:15:35 -05001226int posix_lock_file(struct file *filp, struct file_lock *fl,
Andy Adamson5842add2006-03-26 01:37:26 -08001227 struct file_lock *conflock)
1228{
Miklos Szeredic568d682016-09-16 12:44:20 +02001229 return posix_lock_inode(locks_inode(filp), fl, conflock);
Andy Adamson5842add2006-03-26 01:37:26 -08001230}
Marc Eshel150b3932007-01-18 16:15:35 -05001231EXPORT_SYMBOL(posix_lock_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232
1233/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001234 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1235 * @inode: inode of file to which lock request should be applied
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 * @fl: The lock to be applied
1237 *
Benjamin Coddington616fb382015-10-22 13:38:15 -04001238 * Apply a POSIX style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001240static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241{
1242 int error;
1243 might_sleep ();
1244 for (;;) {
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001245 error = posix_lock_inode(inode, fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001246 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 break;
1248 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1249 if (!error)
1250 continue;
1251
1252 locks_delete_block(fl);
1253 break;
1254 }
1255 return error;
1256}
Jeff Layton29d01b22015-07-11 06:43:02 -04001257
Jeff Layton9e8925b2015-11-16 09:49:34 -05001258#ifdef CONFIG_MANDATORY_FILE_LOCKING
Jeff Layton29d01b22015-07-11 06:43:02 -04001259/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 * locks_mandatory_locked - Check for an active lock
Jeff Laytond7a06982014-03-10 09:54:15 -04001261 * @file: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 *
1263 * Searches the inode's list of locks to find any POSIX locks which conflict.
1264 * This function is called from locks_verify_locked() only.
1265 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001266int locks_mandatory_locked(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001268 int ret;
Miklos Szeredic568d682016-09-16 12:44:20 +02001269 struct inode *inode = locks_inode(file);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001270 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 struct file_lock *fl;
1272
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001273 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001274 if (!ctx || list_empty_careful(&ctx->flc_posix))
1275 return 0;
1276
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 /*
1278 * Search the lock list for this inode for any POSIX locks.
1279 */
Jeff Layton6109c852015-01-16 15:05:57 -05001280 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001281 ret = 0;
1282 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001283 if (fl->fl_owner != current->files &&
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001284 fl->fl_owner != file) {
1285 ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286 break;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001287 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 }
Jeff Layton6109c852015-01-16 15:05:57 -05001289 spin_unlock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001290 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291}
1292
1293/**
1294 * locks_mandatory_area - Check for a conflicting lock
Christoph Hellwigacc15572015-12-03 12:59:49 +01001295 * @inode: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 * @filp: how the file was opened (if it was)
Christoph Hellwigacc15572015-12-03 12:59:49 +01001297 * @start: first byte in the file to check
1298 * @end: lastbyte in the file to check
1299 * @type: %F_WRLCK for a write lock, else %F_RDLCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 *
1301 * Searches the inode's list of locks to find any POSIX locks which conflict.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 */
Christoph Hellwigacc15572015-12-03 12:59:49 +01001303int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1304 loff_t end, unsigned char type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305{
1306 struct file_lock fl;
1307 int error;
Jeff Layton29723ad2014-03-10 09:54:19 -04001308 bool sleep = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309
1310 locks_init_lock(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 fl.fl_pid = current->tgid;
1312 fl.fl_file = filp;
1313 fl.fl_flags = FL_POSIX | FL_ACCESS;
1314 if (filp && !(filp->f_flags & O_NONBLOCK))
Jeff Layton29723ad2014-03-10 09:54:19 -04001315 sleep = true;
Christoph Hellwigacc15572015-12-03 12:59:49 +01001316 fl.fl_type = type;
1317 fl.fl_start = start;
1318 fl.fl_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
1320 for (;;) {
Jeff Layton29723ad2014-03-10 09:54:19 -04001321 if (filp) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001322 fl.fl_owner = filp;
Jeff Layton29723ad2014-03-10 09:54:19 -04001323 fl.fl_flags &= ~FL_SLEEP;
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001324 error = posix_lock_inode(inode, &fl, NULL);
Jeff Layton29723ad2014-03-10 09:54:19 -04001325 if (!error)
1326 break;
1327 }
1328
1329 if (sleep)
1330 fl.fl_flags |= FL_SLEEP;
1331 fl.fl_owner = current->files;
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001332 error = posix_lock_inode(inode, &fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001333 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 break;
1335 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1336 if (!error) {
1337 /*
1338 * If we've been sleeping someone might have
1339 * changed the permissions behind our back.
1340 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07001341 if (__mandatory_lock(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 continue;
1343 }
1344
1345 locks_delete_block(&fl);
1346 break;
1347 }
1348
1349 return error;
1350}
1351
1352EXPORT_SYMBOL(locks_mandatory_area);
Jeff Layton9e8925b2015-11-16 09:49:34 -05001353#endif /* CONFIG_MANDATORY_FILE_LOCKING */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354
J. Bruce Fields778fc542011-07-26 18:25:49 -04001355static void lease_clear_pending(struct file_lock *fl, int arg)
1356{
1357 switch (arg) {
1358 case F_UNLCK:
1359 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1360 /* fall through: */
1361 case F_RDLCK:
1362 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1363 }
1364}
1365
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366/* We already had a lease on this file; just change its type */
Jeff Layton7448cc32015-01-16 15:05:57 -05001367int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 int error = assign_type(fl, arg);
1370
1371 if (error)
1372 return error;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001373 lease_clear_pending(fl, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374 locks_wake_up_blocks(fl);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001375 if (arg == F_UNLCK) {
1376 struct file *filp = fl->fl_file;
1377
1378 f_delown(filp);
1379 filp->f_owner.signum = 0;
J. Bruce Fields96d6d592012-07-27 16:18:00 -04001380 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1381 if (fl->fl_fasync != NULL) {
1382 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1383 fl->fl_fasync = NULL;
1384 }
Jeff Laytone084c1b2015-02-16 14:32:03 -05001385 locks_delete_lock_ctx(fl, dispose);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001386 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 return 0;
1388}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389EXPORT_SYMBOL(lease_modify);
1390
J. Bruce Fields778fc542011-07-26 18:25:49 -04001391static bool past_time(unsigned long then)
1392{
1393 if (!then)
1394 /* 0 is a special value meaning "this never expires": */
1395 return false;
1396 return time_after(jiffies, then);
1397}
1398
Jeff Laytonc45198e2014-09-01 07:12:07 -04001399static void time_out_leases(struct inode *inode, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400{
Jeff Layton8634b512015-01-16 15:05:55 -05001401 struct file_lock_context *ctx = inode->i_flctx;
1402 struct file_lock *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001403
Jeff Layton6109c852015-01-16 15:05:57 -05001404 lockdep_assert_held(&ctx->flc_lock);
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001405
Jeff Layton8634b512015-01-16 15:05:55 -05001406 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001407 trace_time_out_leases(inode, fl);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001408 if (past_time(fl->fl_downgrade_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001409 lease_modify(fl, F_RDLCK, dispose);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001410 if (past_time(fl->fl_break_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001411 lease_modify(fl, F_UNLCK, dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 }
1413}
1414
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001415static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1416{
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001417 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1418 return false;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001419 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1420 return false;
1421 return locks_conflict(breaker, lease);
1422}
1423
Jeff Layton03d12dd2014-09-01 14:53:41 -04001424static bool
1425any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1426{
Jeff Layton8634b512015-01-16 15:05:55 -05001427 struct file_lock_context *ctx = inode->i_flctx;
Jeff Layton03d12dd2014-09-01 14:53:41 -04001428 struct file_lock *fl;
1429
Jeff Layton6109c852015-01-16 15:05:57 -05001430 lockdep_assert_held(&ctx->flc_lock);
Jeff Layton03d12dd2014-09-01 14:53:41 -04001431
Jeff Layton8634b512015-01-16 15:05:55 -05001432 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Jeff Layton03d12dd2014-09-01 14:53:41 -04001433 if (leases_conflict(fl, breaker))
1434 return true;
1435 }
1436 return false;
1437}
1438
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439/**
1440 * __break_lease - revoke all outstanding leases on file
1441 * @inode: the inode of the file to return
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001442 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1443 * break all leases
1444 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1445 * only delegations
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 *
david m. richter87250dd2007-05-09 16:10:27 -04001447 * break_lease (inlined for speed) has checked there already is at least
1448 * some kind of lock (maybe a lease) on this file. Leases are broken on
1449 * a call to open() or truncate(). This function can sleep unless you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450 * specified %O_NONBLOCK to your open().
1451 */
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001452int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453{
J. Bruce Fields778fc542011-07-26 18:25:49 -04001454 int error = 0;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001455 struct file_lock_context *ctx;
Yan, Zhenga9011252015-03-27 10:34:20 +08001456 struct file_lock *new_fl, *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 unsigned long break_time;
Al Viro8737c932009-12-24 06:47:55 -05001458 int want_write = (mode & O_ACCMODE) != O_RDONLY;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001459 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460
Al Viro8737c932009-12-24 06:47:55 -05001461 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001462 if (IS_ERR(new_fl))
1463 return PTR_ERR(new_fl);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001464 new_fl->fl_flags = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465
Jeff Layton8634b512015-01-16 15:05:55 -05001466 /* typically we will check that ctx is non-NULL before calling */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001467 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001468 if (!ctx) {
1469 WARN_ON_ONCE(1);
1470 return error;
1471 }
1472
Peter Zijlstra87709e22016-05-30 16:48:35 +02001473 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001474 spin_lock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475
Jeff Laytonc45198e2014-09-01 07:12:07 -04001476 time_out_leases(inode, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477
Jeff Layton03d12dd2014-09-01 14:53:41 -04001478 if (!any_leases_conflict(inode, new_fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001479 goto out;
1480
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481 break_time = 0;
1482 if (lease_break_time > 0) {
1483 break_time = jiffies + lease_break_time * HZ;
1484 if (break_time == 0)
1485 break_time++; /* so that 0 means no break time */
1486 }
1487
Yan, Zhenga9011252015-03-27 10:34:20 +08001488 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001489 if (!leases_conflict(fl, new_fl))
1490 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001491 if (want_write) {
1492 if (fl->fl_flags & FL_UNLOCK_PENDING)
1493 continue;
1494 fl->fl_flags |= FL_UNLOCK_PENDING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 fl->fl_break_time = break_time;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001496 } else {
Jeff Layton8634b512015-01-16 15:05:55 -05001497 if (lease_breaking(fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001498 continue;
1499 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1500 fl->fl_downgrade_time = break_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501 }
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001502 if (fl->fl_lmops->lm_break(fl))
Jeff Laytone084c1b2015-02-16 14:32:03 -05001503 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 }
1505
Jeff Layton8634b512015-01-16 15:05:55 -05001506 if (list_empty(&ctx->flc_lease))
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001507 goto out;
1508
Jeff Layton843c6b22014-09-01 14:27:43 -04001509 if (mode & O_NONBLOCK) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001510 trace_break_lease_noblock(inode, new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001511 error = -EWOULDBLOCK;
1512 goto out;
1513 }
1514
1515restart:
Jeff Layton8634b512015-01-16 15:05:55 -05001516 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1517 break_time = fl->fl_break_time;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001518 if (break_time != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 break_time -= jiffies;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001520 if (break_time == 0)
1521 break_time++;
Jeff Layton8634b512015-01-16 15:05:55 -05001522 locks_insert_block(fl, new_fl);
Jeff Layton62af4f12014-05-09 14:13:05 -04001523 trace_break_lease_block(inode, new_fl);
Jeff Layton6109c852015-01-16 15:05:57 -05001524 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001525 percpu_up_read_preempt_enable(&file_rwsem);
Peter Zijlstraaba37662015-06-22 14:16:33 +02001526
Jeff Laytonc45198e2014-09-01 07:12:07 -04001527 locks_dispose_list(&dispose);
Matthew Wilcox4321e012008-01-14 21:28:30 -07001528 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1529 !new_fl->fl_next, break_time);
Peter Zijlstraaba37662015-06-22 14:16:33 +02001530
Peter Zijlstra87709e22016-05-30 16:48:35 +02001531 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001532 spin_lock(&ctx->flc_lock);
Jeff Layton62af4f12014-05-09 14:13:05 -04001533 trace_break_lease_unblock(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001534 locks_delete_block(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535 if (error >= 0) {
J. Bruce Fields778fc542011-07-26 18:25:49 -04001536 /*
1537 * Wait for the next conflicting lease that has not been
1538 * broken yet
1539 */
Jeff Layton03d12dd2014-09-01 14:53:41 -04001540 if (error == 0)
1541 time_out_leases(inode, &dispose);
1542 if (any_leases_conflict(inode, new_fl))
1543 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544 error = 0;
1545 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546out:
Jeff Layton6109c852015-01-16 15:05:57 -05001547 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001548 percpu_up_read_preempt_enable(&file_rwsem);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001549 locks_dispose_list(&dispose);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001550 locks_free_lock(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 return error;
1552}
1553
1554EXPORT_SYMBOL(__break_lease);
1555
1556/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001557 * lease_get_mtime - get the last modified time of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558 * @inode: the inode
1559 * @time: pointer to a timespec which will contain the last modified time
1560 *
1561 * This is to force NFS clients to flush their caches for files with
1562 * exclusive leases. The justification is that if someone has an
Randy Dunlapa6b91912008-03-19 17:01:00 -07001563 * exclusive lease, then they could be modifying it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564 */
1565void lease_get_mtime(struct inode *inode, struct timespec *time)
1566{
Jeff Laytonbfe86022014-08-22 10:18:44 -04001567 bool has_lease = false;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001568 struct file_lock_context *ctx;
Jeff Layton8634b512015-01-16 15:05:55 -05001569 struct file_lock *fl;
Jeff Laytonbfe86022014-08-22 10:18:44 -04001570
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001571 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001572 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001573 spin_lock(&ctx->flc_lock);
Geliang Tang8ace5df2015-11-18 21:40:33 +08001574 fl = list_first_entry_or_null(&ctx->flc_lease,
1575 struct file_lock, fl_list);
1576 if (fl && (fl->fl_type == F_WRLCK))
1577 has_lease = true;
Jeff Layton6109c852015-01-16 15:05:57 -05001578 spin_unlock(&ctx->flc_lock);
Jeff Laytonbfe86022014-08-22 10:18:44 -04001579 }
1580
1581 if (has_lease)
Deepa Dinamanic2050a42016-09-14 07:48:06 -07001582 *time = current_time(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 else
1584 *time = inode->i_mtime;
1585}
1586
1587EXPORT_SYMBOL(lease_get_mtime);
1588
1589/**
1590 * fcntl_getlease - Enquire what lease is currently active
1591 * @filp: the file
1592 *
1593 * The value returned by this function will be one of
1594 * (if no lease break is pending):
1595 *
1596 * %F_RDLCK to indicate a shared lease is held.
1597 *
1598 * %F_WRLCK to indicate an exclusive lease is held.
1599 *
1600 * %F_UNLCK to indicate no lease is held.
1601 *
1602 * (if a lease break is pending):
1603 *
1604 * %F_RDLCK to indicate an exclusive lease needs to be
1605 * changed to a shared lease (or removed).
1606 *
1607 * %F_UNLCK to indicate the lease needs to be removed.
1608 *
1609 * XXX: sfr & willy disagree over whether F_INPROGRESS
1610 * should be returned to userspace.
1611 */
1612int fcntl_getlease(struct file *filp)
1613{
1614 struct file_lock *fl;
Miklos Szeredic568d682016-09-16 12:44:20 +02001615 struct inode *inode = locks_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001616 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 int type = F_UNLCK;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001618 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001619
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001620 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001621 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Peter Zijlstra5f430862016-10-08 10:12:28 +02001622 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001623 spin_lock(&ctx->flc_lock);
Miklos Szeredic568d682016-09-16 12:44:20 +02001624 time_out_leases(inode, &dispose);
Jeff Layton8634b512015-01-16 15:05:55 -05001625 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1626 if (fl->fl_file != filp)
1627 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001628 type = target_leasetype(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629 break;
1630 }
Jeff Layton6109c852015-01-16 15:05:57 -05001631 spin_unlock(&ctx->flc_lock);
Peter Zijlstra5f430862016-10-08 10:12:28 +02001632 percpu_up_read_preempt_enable(&file_rwsem);
1633
Jeff Layton8634b512015-01-16 15:05:55 -05001634 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001635 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001636 return type;
1637}
1638
Jeff Layton24cbe782014-02-03 12:13:06 -05001639/**
1640 * check_conflicting_open - see if the given dentry points to a file that has
1641 * an existing open that would conflict with the
1642 * desired lease.
1643 * @dentry: dentry to check
1644 * @arg: type of lease that we're trying to acquire
Randy Dunlap7fadc592015-08-09 18:43:17 -07001645 * @flags: current lock flags
Jeff Layton24cbe782014-02-03 12:13:06 -05001646 *
1647 * Check to see if there's an existing open fd on this file that would
1648 * conflict with the lease we're trying to set.
1649 */
1650static int
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001651check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
Jeff Layton24cbe782014-02-03 12:13:06 -05001652{
1653 int ret = 0;
1654 struct inode *inode = dentry->d_inode;
1655
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001656 if (flags & FL_LAYOUT)
1657 return 0;
1658
Miklos Szeredi4d0c5ba2016-09-16 12:44:21 +02001659 if ((arg == F_RDLCK) &&
1660 (atomic_read(&d_real_inode(dentry)->i_writecount) > 0))
Jeff Layton24cbe782014-02-03 12:13:06 -05001661 return -EAGAIN;
1662
1663 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1664 (atomic_read(&inode->i_count) > 1)))
1665 ret = -EAGAIN;
1666
1667 return ret;
1668}
1669
Jeff Laytone6f5c782014-08-22 10:40:25 -04001670static int
1671generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672{
Jeff Layton8634b512015-01-16 15:05:55 -05001673 struct file_lock *fl, *my_fl = NULL, *lease;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001674 struct dentry *dentry = filp->f_path.dentry;
Miklos Szeredic568d682016-09-16 12:44:20 +02001675 struct inode *inode = dentry->d_inode;
Jeff Layton8634b512015-01-16 15:05:55 -05001676 struct file_lock_context *ctx;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001677 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001678 int error;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001679 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680
J. Bruce Fields096657b2010-10-30 17:31:14 -04001681 lease = *flp;
Jeff Layton62af4f12014-05-09 14:13:05 -04001682 trace_generic_add_lease(inode, lease);
1683
Jeff Layton5c1c6692015-04-03 09:04:03 -04001684 /* Note that arg is never F_UNLCK here */
1685 ctx = locks_get_lock_context(inode, arg);
Jeff Layton8634b512015-01-16 15:05:55 -05001686 if (!ctx)
1687 return -ENOMEM;
1688
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001689 /*
1690 * In the delegation case we need mutual exclusion with
1691 * a number of operations that take the i_mutex. We trylock
1692 * because delegations are an optional optimization, and if
1693 * there's some chance of a conflict--we'd rather not
1694 * bother, maybe that's a sign this just isn't a good file to
1695 * hand out a delegation on.
1696 */
Al Viro59551022016-01-22 15:40:57 -05001697 if (is_deleg && !inode_trylock(inode))
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001698 return -EAGAIN;
1699
1700 if (is_deleg && arg == F_WRLCK) {
1701 /* Write delegations are not currently supported: */
Al Viro59551022016-01-22 15:40:57 -05001702 inode_unlock(inode);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001703 WARN_ON_ONCE(1);
1704 return -EINVAL;
1705 }
J. Bruce Fields096657b2010-10-30 17:31:14 -04001706
Peter Zijlstra87709e22016-05-30 16:48:35 +02001707 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001708 spin_lock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001709 time_out_leases(inode, &dispose);
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001710 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton24cbe782014-02-03 12:13:06 -05001711 if (error)
J. Bruce Fields096657b2010-10-30 17:31:14 -04001712 goto out;
Pavel Emelyanov85c59582007-09-20 12:45:02 +04001713
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 /*
1715 * At this point, we know that if there is an exclusive
1716 * lease on this file, then we hold it on this filp
1717 * (otherwise our open of this file would have blocked).
1718 * And if we are trying to acquire an exclusive lease,
1719 * then the file is not open by anyone (including us)
1720 * except for this filp.
1721 */
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001722 error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001723 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001724 if (fl->fl_file == filp &&
1725 fl->fl_owner == lease->fl_owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001726 my_fl = fl;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001727 continue;
1728 }
Jeff Layton8634b512015-01-16 15:05:55 -05001729
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001730 /*
1731 * No exclusive leases if someone else has a lease on
1732 * this file:
1733 */
1734 if (arg == F_WRLCK)
1735 goto out;
1736 /*
1737 * Modifying our existing lease is OK, but no getting a
1738 * new lease if someone else is opening for write:
1739 */
1740 if (fl->fl_flags & FL_UNLOCK_PENDING)
1741 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 }
1743
Jeff Layton8634b512015-01-16 15:05:55 -05001744 if (my_fl != NULL) {
Jeff Layton0164bf02015-03-04 17:34:32 -05001745 lease = my_fl;
1746 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001747 if (error)
1748 goto out;
1749 goto out_setup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 }
1751
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752 error = -EINVAL;
1753 if (!leases_enable)
1754 goto out;
1755
Jeff Laytone084c1b2015-02-16 14:32:03 -05001756 locks_insert_lock_ctx(lease, &ctx->flc_lease);
Jeff Layton24cbe782014-02-03 12:13:06 -05001757 /*
1758 * The check in break_lease() is lockless. It's possible for another
1759 * open to race in after we did the earlier check for a conflicting
1760 * open but before the lease was inserted. Check again for a
1761 * conflicting open and cancel the lease if there is one.
1762 *
1763 * We also add a barrier here to ensure that the insertion of the lock
1764 * precedes these checks.
1765 */
1766 smp_mb();
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001767 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton8634b512015-01-16 15:05:55 -05001768 if (error) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001769 locks_unlink_lock_ctx(lease);
Jeff Layton8634b512015-01-16 15:05:55 -05001770 goto out;
1771 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001772
1773out_setup:
1774 if (lease->fl_lmops->lm_setup)
1775 lease->fl_lmops->lm_setup(lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776out:
Jeff Layton6109c852015-01-16 15:05:57 -05001777 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001778 percpu_up_read_preempt_enable(&file_rwsem);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001779 locks_dispose_list(&dispose);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001780 if (is_deleg)
Al Viro59551022016-01-22 15:40:57 -05001781 inode_unlock(inode);
Jeff Layton8634b512015-01-16 15:05:55 -05001782 if (!error && !my_fl)
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001783 *flp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 return error;
1785}
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001786
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001787static int generic_delete_lease(struct file *filp, void *owner)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001788{
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001789 int error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001790 struct file_lock *fl, *victim = NULL;
Miklos Szeredic568d682016-09-16 12:44:20 +02001791 struct inode *inode = locks_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001792 struct file_lock_context *ctx;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001793 LIST_HEAD(dispose);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001794
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001795 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001796 if (!ctx) {
1797 trace_generic_delete_lease(inode, NULL);
1798 return error;
1799 }
1800
Peter Zijlstra87709e22016-05-30 16:48:35 +02001801 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001802 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001803 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001804 if (fl->fl_file == filp &&
1805 fl->fl_owner == owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001806 victim = fl;
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001807 break;
Jeff Layton8634b512015-01-16 15:05:55 -05001808 }
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001809 }
Jeff Laytona9b1b452015-03-14 09:45:35 -04001810 trace_generic_delete_lease(inode, victim);
Jeff Layton8634b512015-01-16 15:05:55 -05001811 if (victim)
Jeff Layton7448cc32015-01-16 15:05:57 -05001812 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05001813 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001814 percpu_up_read_preempt_enable(&file_rwsem);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001815 locks_dispose_list(&dispose);
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001816 return error;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001817}
1818
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819/**
1820 * generic_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001821 * @filp: file pointer
1822 * @arg: type of lease to obtain
1823 * @flp: input - file_lock to use, output - file_lock inserted
1824 * @priv: private data for lm_setup (may be NULL if lm_setup
1825 * doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 *
1827 * The (input) flp->fl_lmops->lm_break function is required
1828 * by break_lease().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001830int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1831 void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832{
Miklos Szeredic568d682016-09-16 12:44:20 +02001833 struct inode *inode = locks_inode(filp);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001834 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835
Eric W. Biederman8e96e3b2012-03-03 21:17:15 -08001836 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001837 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 if (!S_ISREG(inode->i_mode))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001839 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840 error = security_file_lock(filp, arg);
1841 if (error)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001842 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001844 switch (arg) {
1845 case F_UNLCK:
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001846 return generic_delete_lease(filp, *priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001847 case F_RDLCK:
1848 case F_WRLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001849 if (!(*flp)->fl_lmops->lm_break) {
1850 WARN_ON_ONCE(1);
1851 return -ENOLCK;
1852 }
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001853
Jeff Laytone6f5c782014-08-22 10:40:25 -04001854 return generic_add_lease(filp, arg, flp, priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001855 default:
Dave Jones8d657eb2012-07-13 13:35:36 -04001856 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858}
Christoph Hellwig0af1a452007-07-31 00:39:22 -07001859EXPORT_SYMBOL(generic_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001860
Arnd Bergmannb89f4322010-09-18 15:09:31 +02001861/**
Jeff Laytone51673a2014-08-22 18:13:28 -04001862 * vfs_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001863 * @filp: file pointer
1864 * @arg: type of lease to obtain
1865 * @lease: file_lock to use when adding a lease
1866 * @priv: private info for lm_setup when adding a lease (may be
1867 * NULL if lm_setup doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868 *
Jeff Laytone51673a2014-08-22 18:13:28 -04001869 * Call this to establish a lease on the file. The "lease" argument is not
1870 * used for F_UNLCK requests and may be NULL. For commands that set or alter
Mauro Carvalho Chehab80b79dd2017-05-27 06:07:18 -04001871 * an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be
1872 * set; if not, this function will return -ENOLCK (and generate a scary-looking
Jeff Laytone51673a2014-08-22 18:13:28 -04001873 * stack trace).
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001874 *
1875 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1876 * may be NULL if the lm_setup operation doesn't require it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001878int
1879vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880{
Miklos Szeredic568d682016-09-16 12:44:20 +02001881 if (filp->f_op->setlease && is_remote_lock(filp))
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001882 return filp->f_op->setlease(filp, arg, lease, priv);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001883 else
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001884 return generic_setlease(filp, arg, lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885}
J. Bruce Fieldsa9933ce2007-06-07 17:09:49 -04001886EXPORT_SYMBOL_GPL(vfs_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001888static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001890 struct file_lock *fl;
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001891 struct fasync_struct *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001892 int error;
1893
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001894 fl = lease_alloc(filp, arg);
1895 if (IS_ERR(fl))
1896 return PTR_ERR(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001898 new = fasync_alloc();
1899 if (!new) {
1900 locks_free_lock(fl);
1901 return -ENOMEM;
1902 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001903 new->fa_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001905 error = vfs_setlease(filp, arg, &fl, (void **)&new);
Jeff Layton2dfb9282014-08-11 18:14:12 -04001906 if (fl)
1907 locks_free_lock(fl);
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001908 if (new)
1909 fasync_free(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 return error;
1911}
1912
1913/**
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001914 * fcntl_setlease - sets a lease on an open file
1915 * @fd: open file descriptor
1916 * @filp: file pointer
1917 * @arg: type of lease to obtain
1918 *
1919 * Call this fcntl to establish a lease on the file.
1920 * Note that you also need to call %F_SETSIG to
1921 * receive a signal when the lease is broken.
1922 */
1923int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1924{
1925 if (arg == F_UNLCK)
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001926 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001927 return do_fcntl_add_lease(fd, filp, arg);
1928}
1929
1930/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001931 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1932 * @inode: inode of the file to apply to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933 * @fl: The lock to be applied
1934 *
Jeff Layton29d01b22015-07-11 06:43:02 -04001935 * Apply a FLOCK style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001937static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001938{
1939 int error;
1940 might_sleep();
1941 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001942 error = flock_lock_inode(inode, fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001943 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944 break;
1945 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1946 if (!error)
1947 continue;
1948
1949 locks_delete_block(fl);
1950 break;
1951 }
1952 return error;
1953}
1954
Jeff Layton29d01b22015-07-11 06:43:02 -04001955/**
Benjamin Coddingtone55c34a2015-10-22 13:38:13 -04001956 * locks_lock_inode_wait - Apply a lock to an inode
1957 * @inode: inode of the file to apply to
1958 * @fl: The lock to be applied
1959 *
1960 * Apply a POSIX or FLOCK style lock request to an inode.
1961 */
1962int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1963{
1964 int res = 0;
1965 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1966 case FL_POSIX:
1967 res = posix_lock_inode_wait(inode, fl);
1968 break;
1969 case FL_FLOCK:
1970 res = flock_lock_inode_wait(inode, fl);
1971 break;
1972 default:
1973 BUG();
1974 }
1975 return res;
1976}
1977EXPORT_SYMBOL(locks_lock_inode_wait);
1978
1979/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 * sys_flock: - flock() system call.
1981 * @fd: the file descriptor to lock.
1982 * @cmd: the type of lock to apply.
1983 *
1984 * Apply a %FL_FLOCK style lock to an open file descriptor.
Mauro Carvalho Chehab80b79dd2017-05-27 06:07:18 -04001985 * The @cmd can be one of:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 *
Mauro Carvalho Chehab80b79dd2017-05-27 06:07:18 -04001987 * - %LOCK_SH -- a shared lock.
1988 * - %LOCK_EX -- an exclusive lock.
1989 * - %LOCK_UN -- remove an existing lock.
1990 * - %LOCK_MAND -- a 'mandatory' flock.
1991 * This exists to emulate Windows Share Modes.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 *
1993 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1994 * processes read and write access respectively.
1995 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001996SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001997{
Al Viro2903ff02012-08-28 12:52:22 -04001998 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001999 struct file_lock *lock;
2000 int can_sleep, unlock;
2001 int error;
2002
2003 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04002004 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005 goto out;
2006
2007 can_sleep = !(cmd & LOCK_NB);
2008 cmd &= ~LOCK_NB;
2009 unlock = (cmd == LOCK_UN);
2010
Al Viroaeb5d722008-09-02 15:28:45 -04002011 if (!unlock && !(cmd & LOCK_MAND) &&
Al Viro2903ff02012-08-28 12:52:22 -04002012 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 goto out_putf;
2014
Jeff Layton6e129d002014-09-04 10:25:06 -04002015 lock = flock_make_lock(f.file, cmd);
2016 if (IS_ERR(lock)) {
2017 error = PTR_ERR(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002018 goto out_putf;
Jeff Layton6e129d002014-09-04 10:25:06 -04002019 }
2020
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021 if (can_sleep)
2022 lock->fl_flags |= FL_SLEEP;
2023
Al Viro2903ff02012-08-28 12:52:22 -04002024 error = security_file_lock(f.file, lock->fl_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002025 if (error)
2026 goto out_free;
2027
Miklos Szeredic568d682016-09-16 12:44:20 +02002028 if (f.file->f_op->flock && is_remote_lock(f.file))
Al Viro2903ff02012-08-28 12:52:22 -04002029 error = f.file->f_op->flock(f.file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002030 (can_sleep) ? F_SETLKW : F_SETLK,
2031 lock);
2032 else
Benjamin Coddington4f656362015-10-22 13:38:14 -04002033 error = locks_lock_file_wait(f.file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034
2035 out_free:
Trond Myklebust993dfa82006-03-31 02:30:55 -08002036 locks_free_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037
2038 out_putf:
Al Viro2903ff02012-08-28 12:52:22 -04002039 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002040 out:
2041 return error;
2042}
2043
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002044/**
2045 * vfs_test_lock - test file byte range lock
2046 * @filp: The file to test lock for
J. Bruce Fields6924c552007-05-11 16:22:50 -04002047 * @fl: The lock to test; also used to hold result
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002048 *
2049 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2050 * setting conf->fl_type to something other than F_UNLCK.
2051 */
2052int vfs_test_lock(struct file *filp, struct file_lock *fl)
2053{
Miklos Szeredic568d682016-09-16 12:44:20 +02002054 if (filp->f_op->lock && is_remote_lock(filp))
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002055 return filp->f_op->lock(filp, F_GETLK, fl);
2056 posix_test_lock(filp, fl);
2057 return 0;
2058}
2059EXPORT_SYMBOL_GPL(vfs_test_lock);
2060
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -04002061/**
2062 * locks_translate_pid - translate a file_lock's fl_pid number into a namespace
2063 * @fl: The file_lock who's fl_pid should be translated
2064 * @ns: The namespace into which the pid should be translated
2065 *
2066 * Used to tranlate a fl_pid into a namespace virtual pid number
2067 */
2068static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns)
2069{
2070 pid_t vnr;
2071 struct pid *pid;
2072
2073 if (IS_OFDLCK(fl))
2074 return -1;
2075 if (IS_REMOTELCK(fl))
2076 return fl->fl_pid;
2077
2078 rcu_read_lock();
2079 pid = find_pid_ns(fl->fl_pid, &init_pid_ns);
2080 vnr = pid_nr_ns(pid, ns);
2081 rcu_read_unlock();
2082 return vnr;
2083}
2084
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002085static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2086{
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -04002087 flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002088#if BITS_PER_LONG == 32
2089 /*
2090 * Make sure we can represent the posix lock via
2091 * legacy 32bit flock.
2092 */
2093 if (fl->fl_start > OFFT_OFFSET_MAX)
2094 return -EOVERFLOW;
2095 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2096 return -EOVERFLOW;
2097#endif
2098 flock->l_start = fl->fl_start;
2099 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2100 fl->fl_end - fl->fl_start + 1;
2101 flock->l_whence = 0;
J. Bruce Fields129a84d2007-05-10 18:38:43 -04002102 flock->l_type = fl->fl_type;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002103 return 0;
2104}
2105
2106#if BITS_PER_LONG == 32
2107static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2108{
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -04002109 flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002110 flock->l_start = fl->fl_start;
2111 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2112 fl->fl_end - fl->fl_start + 1;
2113 flock->l_whence = 0;
2114 flock->l_type = fl->fl_type;
2115}
2116#endif
2117
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118/* Report the first existing lock that would conflict with l.
2119 * This implements the F_GETLK command of fcntl().
2120 */
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002121int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002122{
Benjamin Coddington52306e82017-07-16 10:28:21 -04002123 struct file_lock *fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 int error;
2125
Benjamin Coddington52306e82017-07-16 10:28:21 -04002126 fl = locks_alloc_lock();
2127 if (fl == NULL)
2128 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002129 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002130 if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002131 goto out;
2132
Benjamin Coddington52306e82017-07-16 10:28:21 -04002133 error = flock_to_posix_lock(filp, fl, flock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 if (error)
2135 goto out;
2136
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002137 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002138 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002139 if (flock->l_pid != 0)
Jeff Layton90478932014-03-04 10:30:23 -05002140 goto out;
2141
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002142 cmd = F_GETLK;
Benjamin Coddington52306e82017-07-16 10:28:21 -04002143 fl->fl_flags |= FL_OFDLCK;
2144 fl->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002145 }
2146
Benjamin Coddington52306e82017-07-16 10:28:21 -04002147 error = vfs_test_lock(filp, fl);
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002148 if (error)
2149 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002150
Benjamin Coddington52306e82017-07-16 10:28:21 -04002151 flock->l_type = fl->fl_type;
2152 if (fl->fl_type != F_UNLCK) {
2153 error = posix_lock_to_flock(flock, fl);
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002154 if (error)
Benjamin Coddington52306e82017-07-16 10:28:21 -04002155 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002157out:
Benjamin Coddington52306e82017-07-16 10:28:21 -04002158 locks_free_lock(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002159 return error;
2160}
2161
Marc Eshel7723ec92007-01-18 15:08:55 -05002162/**
2163 * vfs_lock_file - file byte range lock
2164 * @filp: The file to apply the lock to
2165 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2166 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05002167 * @conf: Place to return a copy of the conflicting lock, if found.
2168 *
2169 * A caller that doesn't care about the conflicting lock may pass NULL
2170 * as the final argument.
2171 *
2172 * If the filesystem defines a private ->lock() method, then @conf will
2173 * be left unchanged; so a caller that cares should initialize it to
2174 * some acceptable default.
Marc Eshel2beb6612006-12-05 23:31:28 -05002175 *
2176 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2177 * locks, the ->lock() interface may return asynchronously, before the lock has
2178 * been granted or denied by the underlying filesystem, if (and only if)
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002179 * lm_grant is set. Callers expecting ->lock() to return asynchronously
Marc Eshel2beb6612006-12-05 23:31:28 -05002180 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2181 * the request is for a blocking lock. When ->lock() does return asynchronously,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002182 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
Marc Eshel2beb6612006-12-05 23:31:28 -05002183 * request completes.
2184 * If the request is for non-blocking lock the file system should return
Miklos Szeredibde74e42008-07-25 01:48:57 -07002185 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2186 * with the result. If the request timed out the callback routine will return a
Marc Eshel2beb6612006-12-05 23:31:28 -05002187 * nonzero return code and the file system should release the lock. The file
2188 * system is also responsible to keep a corresponding posix lock when it
2189 * grants a lock so the VFS can find out which locks are locally held and do
2190 * the correct lock cleanup when required.
2191 * The underlying filesystem must not drop the kernel lock or call
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002192 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
Marc Eshel2beb6612006-12-05 23:31:28 -05002193 * return code.
Marc Eshel7723ec92007-01-18 15:08:55 -05002194 */
Marc Eshel150b3932007-01-18 16:15:35 -05002195int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
Marc Eshel7723ec92007-01-18 15:08:55 -05002196{
Miklos Szeredic568d682016-09-16 12:44:20 +02002197 if (filp->f_op->lock && is_remote_lock(filp))
Marc Eshel7723ec92007-01-18 15:08:55 -05002198 return filp->f_op->lock(filp, cmd, fl);
2199 else
Marc Eshel150b3932007-01-18 16:15:35 -05002200 return posix_lock_file(filp, fl, conf);
Marc Eshel7723ec92007-01-18 15:08:55 -05002201}
2202EXPORT_SYMBOL_GPL(vfs_lock_file);
2203
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002204static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2205 struct file_lock *fl)
2206{
2207 int error;
2208
2209 error = security_file_lock(filp, fl->fl_type);
2210 if (error)
2211 return error;
2212
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002213 for (;;) {
2214 error = vfs_lock_file(filp, cmd, fl, NULL);
2215 if (error != FILE_LOCK_DEFERRED)
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002216 break;
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002217 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2218 if (!error)
2219 continue;
2220
2221 locks_delete_block(fl);
2222 break;
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002223 }
2224
2225 return error;
2226}
2227
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04002228/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002229static int
2230check_fmode_for_setlk(struct file_lock *fl)
2231{
2232 switch (fl->fl_type) {
2233 case F_RDLCK:
2234 if (!(fl->fl_file->f_mode & FMODE_READ))
2235 return -EBADF;
2236 break;
2237 case F_WRLCK:
2238 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2239 return -EBADF;
2240 }
2241 return 0;
2242}
2243
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244/* Apply the lock described by l to an open file descriptor.
2245 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2246 */
Peter Staubachc2936212005-07-27 11:45:09 -07002247int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002248 struct flock *flock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002249{
2250 struct file_lock *file_lock = locks_alloc_lock();
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002251 struct inode *inode = locks_inode(filp);
Al Viro0b2bac22008-05-06 13:58:34 -04002252 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253 int error;
2254
2255 if (file_lock == NULL)
2256 return -ENOLCK;
2257
Linus Torvalds1da177e2005-04-16 15:20:36 -07002258 /* Don't allow mandatory locks on files that may be memory mapped
2259 * and shared.
2260 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002261 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 error = -EAGAIN;
2263 goto out;
2264 }
2265
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002266 error = flock_to_posix_lock(filp, file_lock, flock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267 if (error)
2268 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002269
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002270 error = check_fmode_for_setlk(file_lock);
2271 if (error)
2272 goto out;
2273
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002274 /*
2275 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002276 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002277 */
2278 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002279 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002280 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002281 if (flock->l_pid != 0)
Jeff Layton90478932014-03-04 10:30:23 -05002282 goto out;
2283
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002284 cmd = F_SETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002285 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002286 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002287 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002288 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002289 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002290 if (flock->l_pid != 0)
Jeff Layton90478932014-03-04 10:30:23 -05002291 goto out;
2292
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002293 cmd = F_SETLKW;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002294 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002295 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002296 /* Fallthrough */
2297 case F_SETLKW:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002298 file_lock->fl_flags |= FL_SLEEP;
2299 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002300
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002301 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302
Peter Staubachc2936212005-07-27 11:45:09 -07002303 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002304 * Attempt to detect a close/fcntl race and recover by releasing the
2305 * lock that was just acquired. There is no need to do that when we're
2306 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002307 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002308 if (!error && file_lock->fl_type != F_UNLCK &&
2309 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002310 /*
2311 * We need that spin_lock here - it prevents reordering between
2312 * update of i_flctx->flc_posix and check for it done in
2313 * close(). rcu_read_lock() wouldn't do.
2314 */
2315 spin_lock(&current->files->file_lock);
2316 f = fcheck(fd);
2317 spin_unlock(&current->files->file_lock);
2318 if (f != filp) {
2319 file_lock->fl_type = F_UNLCK;
2320 error = do_lock_file_wait(filp, cmd, file_lock);
2321 WARN_ON_ONCE(error);
2322 error = -EBADF;
2323 }
Peter Staubachc2936212005-07-27 11:45:09 -07002324 }
Peter Staubachc2936212005-07-27 11:45:09 -07002325out:
Jeff Layton18909102016-01-06 21:26:10 -05002326 trace_fcntl_setlk(inode, file_lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002327 locks_free_lock(file_lock);
2328 return error;
2329}
2330
2331#if BITS_PER_LONG == 32
2332/* Report the first existing lock that would conflict with l.
2333 * This implements the F_GETLK command of fcntl().
2334 */
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002335int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336{
Benjamin Coddington52306e82017-07-16 10:28:21 -04002337 struct file_lock *fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002338 int error;
2339
Benjamin Coddington52306e82017-07-16 10:28:21 -04002340 fl = locks_alloc_lock();
2341 if (fl == NULL)
2342 return -ENOMEM;
2343
Linus Torvalds1da177e2005-04-16 15:20:36 -07002344 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002345 if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346 goto out;
2347
Benjamin Coddington52306e82017-07-16 10:28:21 -04002348 error = flock64_to_posix_lock(filp, fl, flock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349 if (error)
2350 goto out;
2351
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002352 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002353 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002354 if (flock->l_pid != 0)
Jeff Layton90478932014-03-04 10:30:23 -05002355 goto out;
2356
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002357 cmd = F_GETLK64;
Benjamin Coddington52306e82017-07-16 10:28:21 -04002358 fl->fl_flags |= FL_OFDLCK;
2359 fl->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002360 }
2361
Benjamin Coddington52306e82017-07-16 10:28:21 -04002362 error = vfs_test_lock(filp, fl);
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002363 if (error)
2364 goto out;
2365
Benjamin Coddington52306e82017-07-16 10:28:21 -04002366 flock->l_type = fl->fl_type;
2367 if (fl->fl_type != F_UNLCK)
2368 posix_lock_to_flock64(flock, fl);
Kinglong Meef3282962014-08-22 10:18:43 -04002369
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370out:
Benjamin Coddington52306e82017-07-16 10:28:21 -04002371 locks_free_lock(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002372 return error;
2373}
2374
2375/* Apply the lock described by l to an open file descriptor.
2376 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2377 */
Peter Staubachc2936212005-07-27 11:45:09 -07002378int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002379 struct flock64 *flock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380{
2381 struct file_lock *file_lock = locks_alloc_lock();
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002382 struct inode *inode = locks_inode(filp);
Al Viro0b2bac22008-05-06 13:58:34 -04002383 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002384 int error;
2385
2386 if (file_lock == NULL)
2387 return -ENOLCK;
2388
Linus Torvalds1da177e2005-04-16 15:20:36 -07002389 /* Don't allow mandatory locks on files that may be memory mapped
2390 * and shared.
2391 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002392 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393 error = -EAGAIN;
2394 goto out;
2395 }
2396
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002397 error = flock64_to_posix_lock(filp, file_lock, flock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002398 if (error)
2399 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002400
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002401 error = check_fmode_for_setlk(file_lock);
2402 if (error)
2403 goto out;
2404
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002405 /*
2406 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002407 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002408 */
2409 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002410 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002411 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002412 if (flock->l_pid != 0)
Jeff Layton90478932014-03-04 10:30:23 -05002413 goto out;
2414
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002415 cmd = F_SETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002416 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002417 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002418 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002419 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002420 error = -EINVAL;
Christoph Hellwiga75d30c2017-05-27 06:07:19 -04002421 if (flock->l_pid != 0)
Jeff Layton90478932014-03-04 10:30:23 -05002422 goto out;
2423
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002424 cmd = F_SETLKW64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002425 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002426 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002427 /* Fallthrough */
2428 case F_SETLKW64:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002429 file_lock->fl_flags |= FL_SLEEP;
2430 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002431
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002432 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002433
Peter Staubachc2936212005-07-27 11:45:09 -07002434 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002435 * Attempt to detect a close/fcntl race and recover by releasing the
2436 * lock that was just acquired. There is no need to do that when we're
2437 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002438 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002439 if (!error && file_lock->fl_type != F_UNLCK &&
2440 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002441 /*
2442 * We need that spin_lock here - it prevents reordering between
2443 * update of i_flctx->flc_posix and check for it done in
2444 * close(). rcu_read_lock() wouldn't do.
2445 */
2446 spin_lock(&current->files->file_lock);
2447 f = fcheck(fd);
2448 spin_unlock(&current->files->file_lock);
2449 if (f != filp) {
2450 file_lock->fl_type = F_UNLCK;
2451 error = do_lock_file_wait(filp, cmd, file_lock);
2452 WARN_ON_ONCE(error);
2453 error = -EBADF;
2454 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002456out:
2457 locks_free_lock(file_lock);
2458 return error;
2459}
2460#endif /* BITS_PER_LONG == 32 */
2461
2462/*
2463 * This function is called when the file is being removed
2464 * from the task's fd array. POSIX locks belonging to this task
2465 * are deleted at this time.
2466 */
2467void locks_remove_posix(struct file *filp, fl_owner_t owner)
2468{
Jeff Layton18909102016-01-06 21:26:10 -05002469 int error;
Miklos Szeredic568d682016-09-16 12:44:20 +02002470 struct inode *inode = locks_inode(filp);
Miklos Szerediff7b86b2006-06-23 02:05:11 -07002471 struct file_lock lock;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002472 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002473
2474 /*
2475 * If there are no locks held on this file, we don't need to call
2476 * posix_lock_file(). Another process could be setting a lock on this
2477 * file at the same time, but we wouldn't remove that lock anyway.
2478 */
Miklos Szeredic568d682016-09-16 12:44:20 +02002479 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05002480 if (!ctx || list_empty(&ctx->flc_posix))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002481 return;
2482
2483 lock.fl_type = F_UNLCK;
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07002484 lock.fl_flags = FL_POSIX | FL_CLOSE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002485 lock.fl_start = 0;
2486 lock.fl_end = OFFSET_MAX;
2487 lock.fl_owner = owner;
2488 lock.fl_pid = current->tgid;
2489 lock.fl_file = filp;
2490 lock.fl_ops = NULL;
2491 lock.fl_lmops = NULL;
2492
Jeff Layton18909102016-01-06 21:26:10 -05002493 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002494
Linus Torvalds1da177e2005-04-16 15:20:36 -07002495 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2496 lock.fl_ops->fl_release_private(&lock);
Miklos Szeredic568d682016-09-16 12:44:20 +02002497 trace_locks_remove_posix(inode, &lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002498}
2499
2500EXPORT_SYMBOL(locks_remove_posix);
2501
Jeff Layton3d8e5602015-01-16 15:05:58 -05002502/* The i_flctx must be valid when calling into here */
Jeff Laytondd459bb2015-01-16 15:05:54 -05002503static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002504locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
Jeff Laytondd459bb2015-01-16 15:05:54 -05002505{
2506 struct file_lock fl = {
2507 .fl_owner = filp,
2508 .fl_pid = current->tgid,
2509 .fl_file = filp,
Benjamin Coddington50f21122017-04-11 12:50:09 -04002510 .fl_flags = FL_FLOCK | FL_CLOSE,
Jeff Laytondd459bb2015-01-16 15:05:54 -05002511 .fl_type = F_UNLCK,
2512 .fl_end = OFFSET_MAX,
2513 };
Miklos Szeredic568d682016-09-16 12:44:20 +02002514 struct inode *inode = locks_inode(filp);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002515
Jeff Layton3d8e5602015-01-16 15:05:58 -05002516 if (list_empty(&flctx->flc_flock))
Jeff Laytondd459bb2015-01-16 15:05:54 -05002517 return;
2518
Miklos Szeredic568d682016-09-16 12:44:20 +02002519 if (filp->f_op->flock && is_remote_lock(filp))
Jeff Laytondd459bb2015-01-16 15:05:54 -05002520 filp->f_op->flock(filp, F_SETLKW, &fl);
2521 else
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002522 flock_lock_inode(inode, &fl);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002523
2524 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2525 fl.fl_ops->fl_release_private(&fl);
2526}
2527
Jeff Layton3d8e5602015-01-16 15:05:58 -05002528/* The i_flctx must be valid when calling into here */
Jeff Layton8634b512015-01-16 15:05:55 -05002529static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002530locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
Jeff Layton8634b512015-01-16 15:05:55 -05002531{
Jeff Layton8634b512015-01-16 15:05:55 -05002532 struct file_lock *fl, *tmp;
2533 LIST_HEAD(dispose);
2534
Jeff Layton3d8e5602015-01-16 15:05:58 -05002535 if (list_empty(&ctx->flc_lease))
Jeff Layton8634b512015-01-16 15:05:55 -05002536 return;
2537
Peter Zijlstra5f430862016-10-08 10:12:28 +02002538 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05002539 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002540 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
Jeff Laytonc4e136c2015-02-16 19:37:42 -05002541 if (filp == fl->fl_file)
2542 lease_modify(fl, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05002543 spin_unlock(&ctx->flc_lock);
Peter Zijlstra5f430862016-10-08 10:12:28 +02002544 percpu_up_read_preempt_enable(&file_rwsem);
2545
Jeff Layton8634b512015-01-16 15:05:55 -05002546 locks_dispose_list(&dispose);
2547}
2548
Linus Torvalds1da177e2005-04-16 15:20:36 -07002549/*
2550 * This function is called on the last close of an open file.
2551 */
Jeff Layton78ed8a12014-02-03 12:13:08 -05002552void locks_remove_file(struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002553{
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002554 struct file_lock_context *ctx;
2555
Miklos Szeredic568d682016-09-16 12:44:20 +02002556 ctx = smp_load_acquire(&locks_inode(filp)->i_flctx);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002557 if (!ctx)
Jeff Layton3d8e5602015-01-16 15:05:58 -05002558 return;
2559
Jeff Laytondd459bb2015-01-16 15:05:54 -05002560 /* remove any OFD locks */
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002561 locks_remove_posix(filp, filp);
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002562
Jeff Laytondd459bb2015-01-16 15:05:54 -05002563 /* remove flock locks */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002564 locks_remove_flock(filp, ctx);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002565
Jeff Layton8634b512015-01-16 15:05:55 -05002566 /* remove any leases */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002567 locks_remove_lease(filp, ctx);
Benjamin Coddington39537042017-07-21 13:36:25 -04002568
2569 spin_lock(&ctx->flc_lock);
2570 locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX");
2571 locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK");
2572 locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE");
2573 spin_unlock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002574}
2575
2576/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577 * posix_unblock_lock - stop waiting for a file lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07002578 * @waiter: the lock which was waiting
2579 *
2580 * lockd needs to block waiting for locks.
2581 */
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002582int
Jeff Laytonf891a292013-06-21 08:58:09 -04002583posix_unblock_lock(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002584{
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002585 int status = 0;
2586
Jeff Layton7b2296a2013-06-21 08:58:20 -04002587 spin_lock(&blocked_lock_lock);
J. Bruce Fields5996a292006-01-03 09:55:44 +01002588 if (waiter->fl_next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002589 __locks_delete_block(waiter);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002590 else
2591 status = -ENOENT;
Jeff Layton7b2296a2013-06-21 08:58:20 -04002592 spin_unlock(&blocked_lock_lock);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002593 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002595EXPORT_SYMBOL(posix_unblock_lock);
2596
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002597/**
2598 * vfs_cancel_lock - file byte range unblock lock
2599 * @filp: The file to apply the unblock to
2600 * @fl: The lock to be unblocked
2601 *
2602 * Used by lock managers to cancel blocked requests
2603 */
2604int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2605{
Miklos Szeredic568d682016-09-16 12:44:20 +02002606 if (filp->f_op->lock && is_remote_lock(filp))
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002607 return filp->f_op->lock(filp, F_CANCELLK, fl);
2608 return 0;
2609}
2610
2611EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2612
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002613#ifdef CONFIG_PROC_FS
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002614#include <linux/proc_fs.h>
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002615#include <linux/seq_file.h>
2616
Jeff Layton7012b022013-06-21 08:58:22 -04002617struct locks_iterator {
2618 int li_cpu;
2619 loff_t li_pos;
2620};
2621
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002622static void lock_get_status(struct seq_file *f, struct file_lock *fl,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002623 loff_t id, char *pfx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002624{
2625 struct inode *inode = NULL;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002626 unsigned int fl_pid;
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -04002627 struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002628
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -04002629 fl_pid = locks_translate_pid(fl, proc_pidns);
2630 /*
2631 * If there isn't a fl_pid don't display who is waiting on
2632 * the lock if we are called from locks_show, or if we are
2633 * called from __show_fd_info - skip lock entirely
2634 */
2635 if (fl_pid == 0)
2636 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002637
2638 if (fl->fl_file != NULL)
Miklos Szeredic568d682016-09-16 12:44:20 +02002639 inode = locks_inode(fl->fl_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002640
Jerome Marchand99dc8292010-10-26 14:22:33 -07002641 seq_printf(f, "%lld:%s ", id, pfx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002642 if (IS_POSIX(fl)) {
Jeff Laytonc918d422014-02-03 12:13:09 -05002643 if (fl->fl_flags & FL_ACCESS)
Fabian Frederick5315c262014-05-09 14:13:05 -04002644 seq_puts(f, "ACCESS");
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002645 else if (IS_OFDLCK(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002646 seq_puts(f, "OFDLCK");
Jeff Laytonc918d422014-02-03 12:13:09 -05002647 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002648 seq_puts(f, "POSIX ");
Jeff Laytonc918d422014-02-03 12:13:09 -05002649
2650 seq_printf(f, " %s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651 (inode == NULL) ? "*NOINODE*" :
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002652 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002653 } else if (IS_FLOCK(fl)) {
2654 if (fl->fl_type & LOCK_MAND) {
Fabian Frederick5315c262014-05-09 14:13:05 -04002655 seq_puts(f, "FLOCK MSNFS ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002656 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002657 seq_puts(f, "FLOCK ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002658 }
2659 } else if (IS_LEASE(fl)) {
Jeff Layton8144f1f2014-08-11 13:36:54 -04002660 if (fl->fl_flags & FL_DELEG)
2661 seq_puts(f, "DELEG ");
2662 else
2663 seq_puts(f, "LEASE ");
2664
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002665 if (lease_breaking(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002666 seq_puts(f, "BREAKING ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002667 else if (fl->fl_file)
Fabian Frederick5315c262014-05-09 14:13:05 -04002668 seq_puts(f, "ACTIVE ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002669 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002670 seq_puts(f, "BREAKER ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002671 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002672 seq_puts(f, "UNKNOWN UNKNOWN ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002673 }
2674 if (fl->fl_type & LOCK_MAND) {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002675 seq_printf(f, "%s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002676 (fl->fl_type & LOCK_READ)
2677 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2678 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2679 } else {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002680 seq_printf(f, "%s ",
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002681 (lease_breaking(fl))
Jeff Layton0ee5c6d2012-08-02 15:46:30 -04002682 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2683 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002684 }
2685 if (inode) {
Jeff Layton36488882015-04-03 09:04:04 -04002686 /* userspace relies on this representation of dev_t */
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002687 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002688 MAJOR(inode->i_sb->s_dev),
2689 MINOR(inode->i_sb->s_dev), inode->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002690 } else {
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002691 seq_printf(f, "%d <none>:0 ", fl_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002692 }
2693 if (IS_POSIX(fl)) {
2694 if (fl->fl_end == OFFSET_MAX)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002695 seq_printf(f, "%Ld EOF\n", fl->fl_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002696 else
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002697 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002698 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002699 seq_puts(f, "0 EOF\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002700 }
2701}
2702
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002703static int locks_show(struct seq_file *f, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002704{
Jeff Layton7012b022013-06-21 08:58:22 -04002705 struct locks_iterator *iter = f->private;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002706 struct file_lock *fl, *bfl;
Nikolay Borisovd67fd442016-08-17 16:18:46 -04002707 struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002708
Jeff Layton139ca042013-06-21 08:58:17 -04002709 fl = hlist_entry(v, struct file_lock, fl_link);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002710
Benjamin Coddington9d5b86a2017-07-16 10:28:22 -04002711 if (locks_translate_pid(fl, proc_pidns) == 0)
Nikolay Borisovd67fd442016-08-17 16:18:46 -04002712 return 0;
2713
Jeff Layton7012b022013-06-21 08:58:22 -04002714 lock_get_status(f, fl, iter->li_pos, "");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002715
2716 list_for_each_entry(bfl, &fl->fl_block, fl_block)
Jeff Layton7012b022013-06-21 08:58:22 -04002717 lock_get_status(f, bfl, iter->li_pos, " ->");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002718
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002719 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002720}
2721
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002722static void __show_fd_locks(struct seq_file *f,
2723 struct list_head *head, int *id,
2724 struct file *filp, struct files_struct *files)
2725{
2726 struct file_lock *fl;
2727
2728 list_for_each_entry(fl, head, fl_list) {
2729
2730 if (filp != fl->fl_file)
2731 continue;
2732 if (fl->fl_owner != files &&
2733 fl->fl_owner != filp)
2734 continue;
2735
2736 (*id)++;
2737 seq_puts(f, "lock:\t");
2738 lock_get_status(f, fl, *id, "");
2739 }
2740}
2741
2742void show_fd_locks(struct seq_file *f,
2743 struct file *filp, struct files_struct *files)
2744{
Miklos Szeredic568d682016-09-16 12:44:20 +02002745 struct inode *inode = locks_inode(filp);
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002746 struct file_lock_context *ctx;
2747 int id = 0;
2748
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002749 ctx = smp_load_acquire(&inode->i_flctx);
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002750 if (!ctx)
2751 return;
2752
2753 spin_lock(&ctx->flc_lock);
2754 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2755 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2756 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2757 spin_unlock(&ctx->flc_lock);
2758}
2759
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002760static void *locks_start(struct seq_file *f, loff_t *pos)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002761 __acquires(&blocked_lock_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002762{
Jeff Layton7012b022013-06-21 08:58:22 -04002763 struct locks_iterator *iter = f->private;
Jerome Marchand99dc8292010-10-26 14:22:33 -07002764
Jeff Layton7012b022013-06-21 08:58:22 -04002765 iter->li_pos = *pos + 1;
Peter Zijlstraaba37662015-06-22 14:16:33 +02002766 percpu_down_write(&file_rwsem);
Jeff Layton7b2296a2013-06-21 08:58:20 -04002767 spin_lock(&blocked_lock_lock);
Peter Zijlstra7c3f6542015-06-22 14:16:34 +02002768 return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002769}
2770
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002771static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2772{
Jeff Layton7012b022013-06-21 08:58:22 -04002773 struct locks_iterator *iter = f->private;
2774
2775 ++iter->li_pos;
Peter Zijlstra7c3f6542015-06-22 14:16:34 +02002776 return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002777}
2778
2779static void locks_stop(struct seq_file *f, void *v)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002780 __releases(&blocked_lock_lock)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002781{
Jeff Layton7b2296a2013-06-21 08:58:20 -04002782 spin_unlock(&blocked_lock_lock);
Peter Zijlstraaba37662015-06-22 14:16:33 +02002783 percpu_up_write(&file_rwsem);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002784}
2785
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002786static const struct seq_operations locks_seq_operations = {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002787 .start = locks_start,
2788 .next = locks_next,
2789 .stop = locks_stop,
2790 .show = locks_show,
2791};
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002792
2793static int locks_open(struct inode *inode, struct file *filp)
2794{
Jeff Layton7012b022013-06-21 08:58:22 -04002795 return seq_open_private(filp, &locks_seq_operations,
2796 sizeof(struct locks_iterator));
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002797}
2798
2799static const struct file_operations proc_locks_operations = {
2800 .open = locks_open,
2801 .read = seq_read,
2802 .llseek = seq_lseek,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002803 .release = seq_release_private,
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002804};
2805
2806static int __init proc_locks_init(void)
2807{
2808 proc_create("locks", 0, NULL, &proc_locks_operations);
2809 return 0;
2810}
Paul Gortmaker91899222015-12-17 14:11:03 -05002811fs_initcall(proc_locks_init);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002812#endif
2813
Linus Torvalds1da177e2005-04-16 15:20:36 -07002814static int __init filelock_init(void)
2815{
Jeff Layton7012b022013-06-21 08:58:22 -04002816 int i;
2817
Jeff Layton4a075e32015-01-16 15:05:54 -05002818 flctx_cache = kmem_cache_create("file_lock_ctx",
2819 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2820
Linus Torvalds1da177e2005-04-16 15:20:36 -07002821 filelock_cache = kmem_cache_create("file_lock_cache",
Miklos Szerediee19cc42011-07-07 13:06:09 +02002822 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2823
Jeff Layton7012b022013-06-21 08:58:22 -04002824
Peter Zijlstra7c3f6542015-06-22 14:16:34 +02002825 for_each_possible_cpu(i) {
2826 struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
2827
2828 spin_lock_init(&fll->lock);
2829 INIT_HLIST_HEAD(&fll->hlist);
2830 }
Jeff Layton7012b022013-06-21 08:58:22 -04002831
Linus Torvalds1da177e2005-04-16 15:20:36 -07002832 return 0;
2833}
2834
2835core_initcall(filelock_init);