blob: 133fb2543d21f5242d393143592684f2d16323bb [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 Torvalds1da177e2005-04-16 15:20:36 -0700134#include <asm/uaccess.h>
135
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)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400141static bool lease_breaking(struct file_lock *fl)
142{
J. Bruce Fields778fc542011-07-26 18:25:49 -0400143 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
144}
145
146static int target_leasetype(struct file_lock *fl)
147{
148 if (fl->fl_flags & FL_UNLOCK_PENDING)
149 return F_UNLCK;
150 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
151 return F_RDLCK;
152 return fl->fl_type;
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400153}
154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155int leases_enable = 1;
156int lease_break_time = 45;
157
Jeff Layton1c8c6012013-06-21 08:58:15 -0400158/*
Jeff Layton7012b022013-06-21 08:58:22 -0400159 * The global file_lock_list is only used for displaying /proc/locks, so we
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200160 * keep a list on each CPU, with each list protected by its own spinlock.
161 * Global serialization is done using file_rwsem.
162 *
163 * Note that alterations to the list also require that the relevant flc_lock is
164 * held.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400165 */
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200166struct file_lock_list_struct {
167 spinlock_t lock;
168 struct hlist_head hlist;
169};
170static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
Peter Zijlstraaba37662015-06-22 14:16:33 +0200171DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
Jeff Layton88974692013-06-21 08:58:14 -0400172
Jeff Layton1c8c6012013-06-21 08:58:15 -0400173/*
Jeff Layton48f74182013-06-21 08:58:18 -0400174 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
Jeff Layton7b2296a2013-06-21 08:58:20 -0400175 * It is protected by blocked_lock_lock.
Jeff Layton48f74182013-06-21 08:58:18 -0400176 *
177 * We hash locks by lockowner in order to optimize searching for the lock a
178 * particular lockowner is waiting on.
179 *
180 * FIXME: make this value scale via some heuristic? We generally will want more
181 * buckets when we have more lockowners holding locks, but that's a little
182 * difficult to determine without knowing what the workload will look like.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400183 */
Jeff Layton48f74182013-06-21 08:58:18 -0400184#define BLOCKED_HASH_BITS 7
185static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
Jeff Layton88974692013-06-21 08:58:14 -0400186
Jeff Layton1c8c6012013-06-21 08:58:15 -0400187/*
Jeff Layton7b2296a2013-06-21 08:58:20 -0400188 * This lock protects the blocked_hash. Generally, if you're accessing it, you
189 * want to be holding this lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400190 *
191 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
192 * pointer for file_lock structures that are acting as lock requests (in
193 * contrast to those that are acting as records of acquired locks).
194 *
195 * Note that when we acquire this lock in order to change the above fields,
Jeff Layton6109c852015-01-16 15:05:57 -0500196 * we often hold the flc_lock as well. In certain cases, when reading the fields
Jeff Layton1c8c6012013-06-21 08:58:15 -0400197 * protected by this lock, we can skip acquiring it iff we already hold the
Jeff Layton6109c852015-01-16 15:05:57 -0500198 * flc_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400199 *
200 * In particular, adding an entry to the fl_block list requires that you hold
Jeff Layton6109c852015-01-16 15:05:57 -0500201 * both the flc_lock and the blocked_lock_lock (acquired in that order).
202 * Deleting an entry from the list however only requires the file_lock_lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400203 */
Jeff Layton7b2296a2013-06-21 08:58:20 -0400204static DEFINE_SPINLOCK(blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
Jeff Layton4a075e32015-01-16 15:05:54 -0500206static struct kmem_cache *flctx_cache __read_mostly;
Christoph Lametere18b8902006-12-06 20:33:20 -0800207static struct kmem_cache *filelock_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
Jeff Layton4a075e32015-01-16 15:05:54 -0500209static struct file_lock_context *
Jeff Layton5c1c6692015-04-03 09:04:03 -0400210locks_get_lock_context(struct inode *inode, int type)
Jeff Layton4a075e32015-01-16 15:05:54 -0500211{
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200212 struct file_lock_context *ctx;
Jeff Layton4a075e32015-01-16 15:05:54 -0500213
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200214 /* paired with cmpxchg() below */
215 ctx = smp_load_acquire(&inode->i_flctx);
216 if (likely(ctx) || type == F_UNLCK)
Jeff Layton4a075e32015-01-16 15:05:54 -0500217 goto out;
218
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200219 ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
220 if (!ctx)
Jeff Layton4a075e32015-01-16 15:05:54 -0500221 goto out;
222
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200223 spin_lock_init(&ctx->flc_lock);
224 INIT_LIST_HEAD(&ctx->flc_flock);
225 INIT_LIST_HEAD(&ctx->flc_posix);
226 INIT_LIST_HEAD(&ctx->flc_lease);
Jeff Layton4a075e32015-01-16 15:05:54 -0500227
228 /*
229 * Assign the pointer if it's not already assigned. If it is, then
230 * free the context we just allocated.
231 */
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200232 if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
233 kmem_cache_free(flctx_cache, ctx);
234 ctx = smp_load_acquire(&inode->i_flctx);
235 }
Jeff Layton4a075e32015-01-16 15:05:54 -0500236out:
Jeff Layton18909102016-01-06 21:26:10 -0500237 trace_locks_get_lock_context(inode, type, ctx);
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200238 return ctx;
Jeff Layton4a075e32015-01-16 15:05:54 -0500239}
240
Jeff Laytone24dada2016-01-06 21:28:41 -0500241static void
242locks_dump_ctx_list(struct list_head *list, char *list_type)
243{
244 struct file_lock *fl;
245
246 list_for_each_entry(fl, list, fl_list) {
247 pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
248 }
249}
250
251static void
252locks_check_ctx_lists(struct inode *inode)
253{
254 struct file_lock_context *ctx = inode->i_flctx;
255
256 if (unlikely(!list_empty(&ctx->flc_flock) ||
257 !list_empty(&ctx->flc_posix) ||
258 !list_empty(&ctx->flc_lease))) {
259 pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
260 MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
261 inode->i_ino);
262 locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
263 locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
264 locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
265 }
266}
267
Jeff Layton4a075e32015-01-16 15:05:54 -0500268void
Jeff Laytonf27a0fe2016-01-07 15:08:51 -0500269locks_free_lock_context(struct inode *inode)
Jeff Layton4a075e32015-01-16 15:05:54 -0500270{
Jeff Laytonf27a0fe2016-01-07 15:08:51 -0500271 struct file_lock_context *ctx = inode->i_flctx;
272
Jeff Laytone24dada2016-01-06 21:28:41 -0500273 if (unlikely(ctx)) {
274 locks_check_ctx_lists(inode);
Jeff Layton4a075e32015-01-16 15:05:54 -0500275 kmem_cache_free(flctx_cache, ctx);
276 }
277}
278
Miklos Szerediee19cc42011-07-07 13:06:09 +0200279static void locks_init_lock_heads(struct file_lock *fl)
Miklos Szeredia51cb912011-07-06 12:33:55 +0200280{
Jeff Layton139ca042013-06-21 08:58:17 -0400281 INIT_HLIST_NODE(&fl->fl_link);
Jeff Layton6dee60f2015-01-16 15:05:54 -0500282 INIT_LIST_HEAD(&fl->fl_list);
Miklos Szerediee19cc42011-07-07 13:06:09 +0200283 INIT_LIST_HEAD(&fl->fl_block);
284 init_waitqueue_head(&fl->fl_wait);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200285}
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287/* Allocate an empty lock structure. */
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200288struct file_lock *locks_alloc_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200290 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200291
292 if (fl)
Miklos Szerediee19cc42011-07-07 13:06:09 +0200293 locks_init_lock_heads(fl);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200294
295 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296}
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200297EXPORT_SYMBOL_GPL(locks_alloc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500299void locks_release_private(struct file_lock *fl)
Trond Myklebust47831f32006-03-20 13:44:05 -0500300{
301 if (fl->fl_ops) {
302 if (fl->fl_ops->fl_release_private)
303 fl->fl_ops->fl_release_private(fl);
304 fl->fl_ops = NULL;
305 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500306
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400307 if (fl->fl_lmops) {
Jeff Laytoncae80b32015-04-03 09:04:04 -0400308 if (fl->fl_lmops->lm_put_owner) {
309 fl->fl_lmops->lm_put_owner(fl->fl_owner);
310 fl->fl_owner = NULL;
311 }
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400312 fl->fl_lmops = NULL;
313 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500314}
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500315EXPORT_SYMBOL_GPL(locks_release_private);
Trond Myklebust47831f32006-03-20 13:44:05 -0500316
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317/* Free a lock which is not in use. */
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400318void locks_free_lock(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319{
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800320 BUG_ON(waitqueue_active(&fl->fl_wait));
Jeff Layton6dee60f2015-01-16 15:05:54 -0500321 BUG_ON(!list_empty(&fl->fl_list));
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800322 BUG_ON(!list_empty(&fl->fl_block));
Jeff Layton139ca042013-06-21 08:58:17 -0400323 BUG_ON(!hlist_unhashed(&fl->fl_link));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Trond Myklebust47831f32006-03-20 13:44:05 -0500325 locks_release_private(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 kmem_cache_free(filelock_cache, fl);
327}
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400328EXPORT_SYMBOL(locks_free_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
Jeff Laytoned9814d2014-08-11 14:20:31 -0400330static void
331locks_dispose_list(struct list_head *dispose)
332{
333 struct file_lock *fl;
334
335 while (!list_empty(dispose)) {
Jeff Layton6dee60f2015-01-16 15:05:54 -0500336 fl = list_first_entry(dispose, struct file_lock, fl_list);
337 list_del_init(&fl->fl_list);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400338 locks_free_lock(fl);
339 }
340}
341
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342void locks_init_lock(struct file_lock *fl)
343{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200344 memset(fl, 0, sizeof(struct file_lock));
345 locks_init_lock_heads(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346}
347
348EXPORT_SYMBOL(locks_init_lock);
349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350/*
351 * Initialize a new lock from an existing file_lock structure.
352 */
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400353void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354{
355 new->fl_owner = fl->fl_owner;
356 new->fl_pid = fl->fl_pid;
Trond Myklebust09969052006-03-20 13:44:38 -0500357 new->fl_file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 new->fl_flags = fl->fl_flags;
359 new->fl_type = fl->fl_type;
360 new->fl_start = fl->fl_start;
361 new->fl_end = fl->fl_end;
Kinglong Meef3282962014-08-22 10:18:43 -0400362 new->fl_lmops = fl->fl_lmops;
Trond Myklebust09969052006-03-20 13:44:38 -0500363 new->fl_ops = NULL;
Kinglong Meef3282962014-08-22 10:18:43 -0400364
365 if (fl->fl_lmops) {
366 if (fl->fl_lmops->lm_get_owner)
Jeff Laytoncae80b32015-04-03 09:04:04 -0400367 fl->fl_lmops->lm_get_owner(fl->fl_owner);
Kinglong Meef3282962014-08-22 10:18:43 -0400368 }
Trond Myklebust09969052006-03-20 13:44:38 -0500369}
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400370EXPORT_SYMBOL(locks_copy_conflock);
Trond Myklebust09969052006-03-20 13:44:38 -0500371
372void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
373{
Jeff Layton566709b2014-08-11 14:09:35 -0400374 /* "new" must be a freshly-initialized lock */
375 WARN_ON_ONCE(new->fl_ops);
Trond Myklebust09969052006-03-20 13:44:38 -0500376
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400377 locks_copy_conflock(new, fl);
Kinglong Meef3282962014-08-22 10:18:43 -0400378
Trond Myklebust09969052006-03-20 13:44:38 -0500379 new->fl_file = fl->fl_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 new->fl_ops = fl->fl_ops;
Trond Myklebust47831f32006-03-20 13:44:05 -0500381
Kinglong Meef3282962014-08-22 10:18:43 -0400382 if (fl->fl_ops) {
383 if (fl->fl_ops->fl_copy_lock)
384 fl->fl_ops->fl_copy_lock(new, fl);
385 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386}
387
388EXPORT_SYMBOL(locks_copy_lock);
389
390static inline int flock_translate_cmd(int cmd) {
391 if (cmd & LOCK_MAND)
392 return cmd & (LOCK_MAND | LOCK_RW);
393 switch (cmd) {
394 case LOCK_SH:
395 return F_RDLCK;
396 case LOCK_EX:
397 return F_WRLCK;
398 case LOCK_UN:
399 return F_UNLCK;
400 }
401 return -EINVAL;
402}
403
404/* Fill in a file_lock structure with an appropriate FLOCK lock. */
Jeff Layton6e129d002014-09-04 10:25:06 -0400405static struct file_lock *
406flock_make_lock(struct file *filp, unsigned int cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407{
408 struct file_lock *fl;
409 int type = flock_translate_cmd(cmd);
Jeff Layton6e129d002014-09-04 10:25:06 -0400410
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 if (type < 0)
Jeff Layton6e129d002014-09-04 10:25:06 -0400412 return ERR_PTR(type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413
414 fl = locks_alloc_lock();
415 if (fl == NULL)
Jeff Layton6e129d002014-09-04 10:25:06 -0400416 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
418 fl->fl_file = filp;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +0200419 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 fl->fl_pid = current->tgid;
421 fl->fl_flags = FL_FLOCK;
422 fl->fl_type = type;
423 fl->fl_end = OFFSET_MAX;
424
Jeff Layton6e129d002014-09-04 10:25:06 -0400425 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426}
427
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400428static int assign_type(struct file_lock *fl, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429{
430 switch (type) {
431 case F_RDLCK:
432 case F_WRLCK:
433 case F_UNLCK:
434 fl->fl_type = type;
435 break;
436 default:
437 return -EINVAL;
438 }
439 return 0;
440}
441
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500442static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
443 struct flock64 *l)
444{
445 switch (l->l_whence) {
446 case SEEK_SET:
447 fl->fl_start = 0;
448 break;
449 case SEEK_CUR:
450 fl->fl_start = filp->f_pos;
451 break;
452 case SEEK_END:
453 fl->fl_start = i_size_read(file_inode(filp));
454 break;
455 default:
456 return -EINVAL;
457 }
458 if (l->l_start > OFFSET_MAX - fl->fl_start)
459 return -EOVERFLOW;
460 fl->fl_start += l->l_start;
461 if (fl->fl_start < 0)
462 return -EINVAL;
463
464 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
465 POSIX-2001 defines it. */
466 if (l->l_len > 0) {
467 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
468 return -EOVERFLOW;
469 fl->fl_end = fl->fl_start + l->l_len - 1;
470
471 } else if (l->l_len < 0) {
472 if (fl->fl_start + l->l_len < 0)
473 return -EINVAL;
474 fl->fl_end = fl->fl_start - 1;
475 fl->fl_start += l->l_len;
476 } else
477 fl->fl_end = OFFSET_MAX;
478
479 fl->fl_owner = current->files;
480 fl->fl_pid = current->tgid;
481 fl->fl_file = filp;
482 fl->fl_flags = FL_POSIX;
483 fl->fl_ops = NULL;
484 fl->fl_lmops = NULL;
485
486 return assign_type(fl, l->l_type);
487}
488
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
490 * style lock.
491 */
492static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
493 struct flock *l)
494{
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500495 struct flock64 ll = {
496 .l_type = l->l_type,
497 .l_whence = l->l_whence,
498 .l_start = l->l_start,
499 .l_len = l->l_len,
500 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500502 return flock64_to_posix_lock(filp, fl, &ll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503}
504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505/* default lease lock manager operations */
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400506static bool
507lease_break_callback(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508{
509 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
Jeff Layton4d01b7f2014-09-01 15:06:54 -0400510 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511}
512
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400513static void
514lease_setup(struct file_lock *fl, void **priv)
515{
516 struct file *filp = fl->fl_file;
517 struct fasync_struct *fa = *priv;
518
519 /*
520 * fasync_insert_entry() returns the old entry if any. If there was no
521 * old entry, then it used "priv" and inserted it into the fasync list.
522 * Clear the pointer to indicate that it shouldn't be freed.
523 */
524 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
525 *priv = NULL;
526
527 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
528}
529
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700530static const struct lock_manager_operations lease_manager_ops = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400531 .lm_break = lease_break_callback,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400532 .lm_change = lease_modify,
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400533 .lm_setup = lease_setup,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534};
535
536/*
537 * Initialize a lease, use the default lock manager operations
538 */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400539static int lease_init(struct file *filp, long type, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 {
Trond Myklebust75dff552006-05-07 23:02:42 -0400541 if (assign_type(fl, type) != 0)
542 return -EINVAL;
543
Jeff Layton7ca76312014-09-01 19:04:48 -0400544 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 fl->fl_pid = current->tgid;
546
547 fl->fl_file = filp;
548 fl->fl_flags = FL_LEASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 fl->fl_start = 0;
550 fl->fl_end = OFFSET_MAX;
551 fl->fl_ops = NULL;
552 fl->fl_lmops = &lease_manager_ops;
553 return 0;
554}
555
556/* Allocate a file_lock initialised to this type of lease */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400557static struct file_lock *lease_alloc(struct file *filp, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558{
559 struct file_lock *fl = locks_alloc_lock();
Trond Myklebust75dff552006-05-07 23:02:42 -0400560 int error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562 if (fl == NULL)
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500563 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565 error = lease_init(filp, type, fl);
Trond Myklebust75dff552006-05-07 23:02:42 -0400566 if (error) {
567 locks_free_lock(fl);
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500568 return ERR_PTR(error);
Trond Myklebust75dff552006-05-07 23:02:42 -0400569 }
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500570 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571}
572
573/* Check if two locks overlap each other.
574 */
575static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
576{
577 return ((fl1->fl_end >= fl2->fl_start) &&
578 (fl2->fl_end >= fl1->fl_start));
579}
580
581/*
582 * Check whether two locks have the same owner.
583 */
Matt Mackall33443c42006-01-08 01:05:22 -0800584static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585{
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400586 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 return fl2->fl_lmops == fl1->fl_lmops &&
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400588 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 return fl1->fl_owner == fl2->fl_owner;
590}
591
Jeff Layton6109c852015-01-16 15:05:57 -0500592/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500593static void locks_insert_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400594{
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200595 struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
596
Peter Zijlstraaba37662015-06-22 14:16:33 +0200597 percpu_rwsem_assert_held(&file_rwsem);
598
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200599 spin_lock(&fll->lock);
Jeff Layton7012b022013-06-21 08:58:22 -0400600 fl->fl_link_cpu = smp_processor_id();
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200601 hlist_add_head(&fl->fl_link, &fll->hlist);
602 spin_unlock(&fll->lock);
Jeff Layton88974692013-06-21 08:58:14 -0400603}
604
Jeff Layton6109c852015-01-16 15:05:57 -0500605/* Must be called with the flc_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500606static void locks_delete_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400607{
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200608 struct file_lock_list_struct *fll;
609
Peter Zijlstraaba37662015-06-22 14:16:33 +0200610 percpu_rwsem_assert_held(&file_rwsem);
611
Jeff Layton7012b022013-06-21 08:58:22 -0400612 /*
613 * Avoid taking lock if already unhashed. This is safe since this check
Jeff Layton6109c852015-01-16 15:05:57 -0500614 * is done while holding the flc_lock, and new insertions into the list
Jeff Layton7012b022013-06-21 08:58:22 -0400615 * also require that it be held.
616 */
617 if (hlist_unhashed(&fl->fl_link))
618 return;
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200619
620 fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
621 spin_lock(&fll->lock);
Jeff Layton139ca042013-06-21 08:58:17 -0400622 hlist_del_init(&fl->fl_link);
Peter Zijlstra7c3f6542015-06-22 14:16:34 +0200623 spin_unlock(&fll->lock);
Jeff Layton88974692013-06-21 08:58:14 -0400624}
625
Jeff Layton3999e492013-06-21 08:58:19 -0400626static unsigned long
627posix_owner_key(struct file_lock *fl)
628{
629 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
630 return fl->fl_lmops->lm_owner_key(fl);
631 return (unsigned long)fl->fl_owner;
632}
633
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500634static void locks_insert_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400635{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400636 lockdep_assert_held(&blocked_lock_lock);
637
Jeff Layton3999e492013-06-21 08:58:19 -0400638 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
Jeff Layton88974692013-06-21 08:58:14 -0400639}
640
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500641static void locks_delete_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400642{
Daniel Wagner663d5af2015-04-03 09:04:03 -0400643 lockdep_assert_held(&blocked_lock_lock);
644
Jeff Layton48f74182013-06-21 08:58:18 -0400645 hash_del(&waiter->fl_link);
Jeff Layton88974692013-06-21 08:58:14 -0400646}
647
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648/* Remove waiter from blocker's block list.
649 * When blocker ends up pointing to itself then the list is empty.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400650 *
Jeff Layton7b2296a2013-06-21 08:58:20 -0400651 * Must be called with blocked_lock_lock held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 */
Matt Mackall33443c42006-01-08 01:05:22 -0800653static void __locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654{
Jeff Layton88974692013-06-21 08:58:14 -0400655 locks_delete_global_blocked(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 list_del_init(&waiter->fl_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 waiter->fl_next = NULL;
658}
659
Jeff Layton1a9e64a2013-06-21 08:58:10 -0400660static void locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400662 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 __locks_delete_block(waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400664 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665}
666
667/* Insert waiter into blocker's block list.
668 * We use a circular list so that processes can be easily woken up in
669 * the order they blocked. The documentation doesn't require this but
670 * it seems like the reasonable thing to do.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400671 *
Jeff Layton6109c852015-01-16 15:05:57 -0500672 * Must be called with both the flc_lock and blocked_lock_lock held. The
673 * fl_block list itself is protected by the blocked_lock_lock, but by ensuring
674 * that the flc_lock is also held on insertions we can avoid taking the
675 * blocked_lock_lock in some cases when we see that the fl_block list is empty.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400677static void __locks_insert_block(struct file_lock *blocker,
678 struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679{
J. Bruce Fields6dc0fe82006-03-26 01:37:24 -0800680 BUG_ON(!list_empty(&waiter->fl_block));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 waiter->fl_next = blocker;
Jeff Layton88974692013-06-21 08:58:14 -0400682 list_add_tail(&waiter->fl_block, &blocker->fl_block);
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400683 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
Jeff Layton1c8c6012013-06-21 08:58:15 -0400684 locks_insert_global_blocked(waiter);
685}
686
Jeff Layton6109c852015-01-16 15:05:57 -0500687/* Must be called with flc_lock held. */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400688static void locks_insert_block(struct file_lock *blocker,
689 struct file_lock *waiter)
690{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400691 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400692 __locks_insert_block(blocker, waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400693 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694}
695
Jeff Layton1cb36012013-06-21 08:58:12 -0400696/*
697 * Wake up processes blocked waiting for blocker.
698 *
Jeff Layton6109c852015-01-16 15:05:57 -0500699 * Must be called with the inode->flc_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 */
701static void locks_wake_up_blocks(struct file_lock *blocker)
702{
Jeff Layton4e8c7652013-06-21 08:58:16 -0400703 /*
704 * Avoid taking global lock if list is empty. This is safe since new
Jeff Layton6109c852015-01-16 15:05:57 -0500705 * blocked requests are only added to the list under the flc_lock, and
706 * the flc_lock is always held here. Note that removal from the fl_block
707 * list does not require the flc_lock, so we must recheck list_empty()
Jeff Layton7b2296a2013-06-21 08:58:20 -0400708 * after acquiring the blocked_lock_lock.
Jeff Layton4e8c7652013-06-21 08:58:16 -0400709 */
710 if (list_empty(&blocker->fl_block))
711 return;
712
Jeff Layton7b2296a2013-06-21 08:58:20 -0400713 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 while (!list_empty(&blocker->fl_block)) {
Pavel Emelyanovf0c1cd02007-09-19 16:44:07 +0400715 struct file_lock *waiter;
716
717 waiter = list_first_entry(&blocker->fl_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 struct file_lock, fl_block);
719 __locks_delete_block(waiter);
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400720 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
721 waiter->fl_lmops->lm_notify(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 else
723 wake_up(&waiter->fl_wait);
724 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400725 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726}
727
Jeff Layton5263e312015-01-16 15:05:55 -0500728static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500729locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
Jeff Layton5263e312015-01-16 15:05:55 -0500730{
731 fl->fl_nspid = get_pid(task_tgid(current));
732 list_add_tail(&fl->fl_list, before);
733 locks_insert_global_locks(fl);
734}
735
Jeff Layton8634b512015-01-16 15:05:55 -0500736static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500737locks_unlink_lock_ctx(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738{
Jeff Layton88974692013-06-21 08:58:14 -0400739 locks_delete_global_locks(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500740 list_del_init(&fl->fl_list);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000741 if (fl->fl_nspid) {
742 put_pid(fl->fl_nspid);
743 fl->fl_nspid = NULL;
744 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 locks_wake_up_blocks(fl);
Jeff Layton24cbe782014-02-03 12:13:06 -0500746}
747
Jeff Layton5263e312015-01-16 15:05:55 -0500748static void
Jeff Laytone084c1b2015-02-16 14:32:03 -0500749locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
Jeff Layton5263e312015-01-16 15:05:55 -0500750{
Jeff Laytone084c1b2015-02-16 14:32:03 -0500751 locks_unlink_lock_ctx(fl);
Jeff Layton8634b512015-01-16 15:05:55 -0500752 if (dispose)
753 list_add(&fl->fl_list, dispose);
754 else
755 locks_free_lock(fl);
Jeff Layton5263e312015-01-16 15:05:55 -0500756}
757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
759 * checks for shared/exclusive status of overlapping locks.
760 */
761static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
762{
763 if (sys_fl->fl_type == F_WRLCK)
764 return 1;
765 if (caller_fl->fl_type == F_WRLCK)
766 return 1;
767 return 0;
768}
769
770/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
771 * checking before calling the locks_conflict().
772 */
773static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
774{
775 /* POSIX locks owned by the same process do not conflict with
776 * each other.
777 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400778 if (posix_same_owner(caller_fl, sys_fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 return (0);
780
781 /* Check whether they overlap */
782 if (!locks_overlap(caller_fl, sys_fl))
783 return 0;
784
785 return (locks_conflict(caller_fl, sys_fl));
786}
787
788/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
789 * checking before calling the locks_conflict().
790 */
791static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
792{
793 /* FLOCK locks referring to the same filp do not conflict with
794 * each other.
795 */
Jeff Layton9b8c8692015-04-03 09:04:02 -0400796 if (caller_fl->fl_file == sys_fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 return (0);
798 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
799 return 0;
800
801 return (locks_conflict(caller_fl, sys_fl));
802}
803
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400804void
Marc Eshel9d6a8c52007-02-21 00:55:18 -0500805posix_test_lock(struct file *filp, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806{
807 struct file_lock *cfl;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500808 struct file_lock_context *ctx;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400809 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810
Dmitry Vyukov128a3782015-09-21 09:43:06 +0200811 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500812 if (!ctx || list_empty_careful(&ctx->flc_posix)) {
J. Bruce Fields129a84d2007-05-10 18:38:43 -0400813 fl->fl_type = F_UNLCK;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500814 return;
815 }
816
Jeff Layton6109c852015-01-16 15:05:57 -0500817 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500818 list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
819 if (posix_locks_conflict(fl, cfl)) {
820 locks_copy_conflock(fl, cfl);
821 if (cfl->fl_nspid)
822 fl->fl_pid = pid_vnr(cfl->fl_nspid);
823 goto out;
824 }
825 }
826 fl->fl_type = F_UNLCK;
827out:
Jeff Layton6109c852015-01-16 15:05:57 -0500828 spin_unlock(&ctx->flc_lock);
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400829 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831EXPORT_SYMBOL(posix_test_lock);
832
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400833/*
834 * Deadlock detection:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400836 * We attempt to detect deadlocks that are due purely to posix file
837 * locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400839 * We assume that a task can be waiting for at most one lock at a time.
840 * So for any acquired lock, the process holding that lock may be
841 * waiting on at most one other lock. That lock in turns may be held by
842 * someone waiting for at most one other lock. Given a requested lock
843 * caller_fl which is about to wait for a conflicting lock block_fl, we
844 * follow this chain of waiters to ensure we are not about to create a
845 * cycle.
J. Bruce Fields97855b42007-10-30 11:20:02 -0400846 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400847 * Since we do this before we ever put a process to sleep on a lock, we
848 * are ensured that there is never a cycle; that is what guarantees that
849 * the while() loop in posix_locks_deadlock() eventually completes.
850 *
851 * Note: the above assumption may not be true when handling lock
852 * requests from a broken NFS client. It may also fail in the presence
853 * of tasks (such as posix threads) sharing the same open file table.
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400854 * To handle those cases, we just bail out after a few iterations.
Jeff Layton57b65322014-02-03 12:13:09 -0500855 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400856 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
Jeff Layton57b65322014-02-03 12:13:09 -0500857 * Because the owner is not even nominally tied to a thread of
858 * execution, the deadlock detection below can't reasonably work well. Just
859 * skip it for those.
860 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400861 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
Jeff Layton57b65322014-02-03 12:13:09 -0500862 * locks that just checks for the case where two tasks are attempting to
863 * upgrade from read to write locks on the same inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 */
J. Bruce Fields97855b42007-10-30 11:20:02 -0400865
866#define MAX_DEADLK_ITERATIONS 10
867
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400868/* Find a lock that the owner of the given block_fl is blocking on. */
869static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
870{
871 struct file_lock *fl;
872
Jeff Layton3999e492013-06-21 08:58:19 -0400873 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400874 if (posix_same_owner(fl, block_fl))
875 return fl->fl_next;
876 }
877 return NULL;
878}
879
Jeff Layton7b2296a2013-06-21 08:58:20 -0400880/* Must be called with the blocked_lock_lock held! */
Adrian Bunkb0904e12006-06-23 02:05:13 -0700881static int posix_locks_deadlock(struct file_lock *caller_fl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 struct file_lock *block_fl)
883{
J. Bruce Fields97855b42007-10-30 11:20:02 -0400884 int i = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885
Daniel Wagner663d5af2015-04-03 09:04:03 -0400886 lockdep_assert_held(&blocked_lock_lock);
887
Jeff Layton57b65322014-02-03 12:13:09 -0500888 /*
889 * This deadlock detector can't reasonably detect deadlocks with
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400890 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
Jeff Layton57b65322014-02-03 12:13:09 -0500891 */
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400892 if (IS_OFDLCK(caller_fl))
Jeff Layton57b65322014-02-03 12:13:09 -0500893 return 0;
894
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400895 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
896 if (i++ > MAX_DEADLK_ITERATIONS)
897 return 0;
898 if (posix_same_owner(caller_fl, block_fl))
899 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 }
901 return 0;
902}
903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
J. Bruce Fields02888f42007-09-12 15:45:07 -0400905 * after any leases, but before any posix locks.
Trond Myklebustf475ae92006-06-29 16:38:32 -0400906 *
907 * Note that if called with an FL_EXISTS argument, the caller may determine
908 * whether or not a lock was successfully freed by testing the return
909 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 */
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400911static int flock_lock_inode(struct inode *inode, struct file_lock *request)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912{
Trond Myklebust993dfa82006-03-31 02:30:55 -0800913 struct file_lock *new_fl = NULL;
Jeff Layton5263e312015-01-16 15:05:55 -0500914 struct file_lock *fl;
915 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 int error = 0;
Jeff Layton5263e312015-01-16 15:05:55 -0500917 bool found = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400918 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919
Jeff Layton5c1c6692015-04-03 09:04:03 -0400920 ctx = locks_get_lock_context(inode, request->fl_type);
921 if (!ctx) {
922 if (request->fl_type != F_UNLCK)
923 return -ENOMEM;
924 return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
925 }
Jeff Layton5263e312015-01-16 15:05:55 -0500926
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200927 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
928 new_fl = locks_alloc_lock();
929 if (!new_fl)
930 return -ENOMEM;
931 }
932
Peter Zijlstra87709e22016-05-30 16:48:35 +0200933 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -0500934 spin_lock(&ctx->flc_lock);
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400935 if (request->fl_flags & FL_ACCESS)
936 goto find_conflict;
Pavel Emelyanov84d535a2007-09-11 16:38:13 +0400937
Jeff Layton5263e312015-01-16 15:05:55 -0500938 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Jeff Laytonbcd7f782015-07-11 06:43:02 -0400939 if (request->fl_file != fl->fl_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940 continue;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800941 if (request->fl_type == fl->fl_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 goto out;
Jeff Layton5263e312015-01-16 15:05:55 -0500943 found = true;
Jeff Laytone084c1b2015-02-16 14:32:03 -0500944 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 break;
946 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947
Trond Myklebustf475ae92006-06-29 16:38:32 -0400948 if (request->fl_type == F_UNLCK) {
949 if ((request->fl_flags & FL_EXISTS) && !found)
950 error = -ENOENT;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800951 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -0400952 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400954find_conflict:
Jeff Layton5263e312015-01-16 15:05:55 -0500955 list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
Trond Myklebust993dfa82006-03-31 02:30:55 -0800956 if (!flock_locks_conflict(request, fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 continue;
958 error = -EAGAIN;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700959 if (!(request->fl_flags & FL_SLEEP))
960 goto out;
961 error = FILE_LOCK_DEFERRED;
962 locks_insert_block(fl, request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 goto out;
964 }
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400965 if (request->fl_flags & FL_ACCESS)
966 goto out;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800967 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -0500968 locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800969 new_fl = NULL;
Kirill Korotaev9cedc192006-06-14 17:59:35 +0400970 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971
972out:
Jeff Layton6109c852015-01-16 15:05:57 -0500973 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +0200974 percpu_up_read_preempt_enable(&file_rwsem);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800975 if (new_fl)
976 locks_free_lock(new_fl);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400977 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 return error;
979}
980
Jeff Laytonb4d629a2016-01-07 18:27:42 -0500981static int posix_lock_inode(struct inode *inode, struct file_lock *request,
982 struct file_lock *conflock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500984 struct file_lock *fl, *tmp;
Miklos Szeredi39005d02006-06-23 02:05:10 -0700985 struct file_lock *new_fl = NULL;
986 struct file_lock *new_fl2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 struct file_lock *left = NULL;
988 struct file_lock *right = NULL;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500989 struct file_lock_context *ctx;
Jeff Laytonb9746ef2013-06-21 08:58:13 -0400990 int error;
991 bool added = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400992 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993
Jeff Layton5c1c6692015-04-03 09:04:03 -0400994 ctx = locks_get_lock_context(inode, request->fl_type);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500995 if (!ctx)
Jeff Layton5c1c6692015-04-03 09:04:03 -0400996 return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -0500997
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 /*
999 * We may need two file_lock structures for this operation,
1000 * so we get them in advance to avoid races.
Miklos Szeredi39005d02006-06-23 02:05:10 -07001001 *
1002 * In some cases we can be sure, that no new locks will be needed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 */
Miklos Szeredi39005d02006-06-23 02:05:10 -07001004 if (!(request->fl_flags & FL_ACCESS) &&
1005 (request->fl_type != F_UNLCK ||
1006 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
1007 new_fl = locks_alloc_lock();
1008 new_fl2 = locks_alloc_lock();
1009 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010
Peter Zijlstra87709e22016-05-30 16:48:35 +02001011 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001012 spin_lock(&ctx->flc_lock);
Jeff Layton1cb36012013-06-21 08:58:12 -04001013 /*
1014 * New lock request. Walk all POSIX locks and look for conflicts. If
1015 * there are any, either return error or put the request on the
Jeff Layton48f74182013-06-21 08:58:18 -04001016 * blocker's list of waiters and the global blocked_hash.
Jeff Layton1cb36012013-06-21 08:58:12 -04001017 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 if (request->fl_type != F_UNLCK) {
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001019 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 if (!posix_locks_conflict(request, fl))
1021 continue;
Andy Adamson5842add2006-03-26 01:37:26 -08001022 if (conflock)
Kinglong Mee3fe0fff12014-08-22 10:18:42 -04001023 locks_copy_conflock(conflock, fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 error = -EAGAIN;
1025 if (!(request->fl_flags & FL_SLEEP))
1026 goto out;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001027 /*
1028 * Deadlock detection and insertion into the blocked
1029 * locks list must be done while holding the same lock!
1030 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 error = -EDEADLK;
Jeff Layton7b2296a2013-06-21 08:58:20 -04001032 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001033 if (likely(!posix_locks_deadlock(request, fl))) {
1034 error = FILE_LOCK_DEFERRED;
1035 __locks_insert_block(fl, request);
1036 }
Jeff Layton7b2296a2013-06-21 08:58:20 -04001037 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 goto out;
1039 }
1040 }
1041
1042 /* If we're just looking for a conflict, we're done. */
1043 error = 0;
1044 if (request->fl_flags & FL_ACCESS)
1045 goto out;
1046
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001047 /* Find the first old lock with the same owner as the new lock */
1048 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
1049 if (posix_same_owner(request, fl))
1050 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 }
1052
Jeff Layton1cb36012013-06-21 08:58:12 -04001053 /* Process locks with this owner. */
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001054 list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
1055 if (!posix_same_owner(request, fl))
1056 break;
1057
1058 /* Detect adjacent or overlapping regions (if same lock type) */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059 if (request->fl_type == fl->fl_type) {
Olaf Kirch449231d2005-08-25 16:25:35 -07001060 /* In all comparisons of start vs end, use
1061 * "start - 1" rather than "end + 1". If end
1062 * is OFFSET_MAX, end + 1 will become negative.
1063 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 if (fl->fl_end < request->fl_start - 1)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001065 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 /* If the next lock in the list has entirely bigger
1067 * addresses than the new one, insert the lock here.
1068 */
Olaf Kirch449231d2005-08-25 16:25:35 -07001069 if (fl->fl_start - 1 > request->fl_end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 break;
1071
1072 /* If we come here, the new and old lock are of the
1073 * same type and adjacent or overlapping. Make one
1074 * lock yielding from the lower start address of both
1075 * locks to the higher end address.
1076 */
1077 if (fl->fl_start > request->fl_start)
1078 fl->fl_start = request->fl_start;
1079 else
1080 request->fl_start = fl->fl_start;
1081 if (fl->fl_end < request->fl_end)
1082 fl->fl_end = request->fl_end;
1083 else
1084 request->fl_end = fl->fl_end;
1085 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001086 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 continue;
1088 }
1089 request = fl;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001090 added = true;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001091 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 /* Processing for different lock types is a bit
1093 * more complex.
1094 */
1095 if (fl->fl_end < request->fl_start)
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001096 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 if (fl->fl_start > request->fl_end)
1098 break;
1099 if (request->fl_type == F_UNLCK)
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001100 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 if (fl->fl_start < request->fl_start)
1102 left = fl;
1103 /* If the next lock in the list has a higher end
1104 * address than the new one, insert the new one here.
1105 */
1106 if (fl->fl_end > request->fl_end) {
1107 right = fl;
1108 break;
1109 }
1110 if (fl->fl_start >= request->fl_start) {
1111 /* The new lock completely replaces an old
1112 * one (This may happen several times).
1113 */
1114 if (added) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001115 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 continue;
1117 }
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001118 /*
1119 * Replace the old lock with new_fl, and
1120 * remove the old one. It's safe to do the
1121 * insert here since we know that we won't be
1122 * using new_fl later, and that the lock is
1123 * just replacing an existing lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124 */
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001125 error = -ENOLCK;
1126 if (!new_fl)
1127 goto out;
1128 locks_copy_lock(new_fl, request);
1129 request = new_fl;
1130 new_fl = NULL;
Jeff Laytone084c1b2015-02-16 14:32:03 -05001131 locks_insert_lock_ctx(request, &fl->fl_list);
1132 locks_delete_lock_ctx(fl, &dispose);
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001133 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 }
1135 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 }
1137
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001138 /*
Jeff Layton1cb36012013-06-21 08:58:12 -04001139 * The above code only modifies existing locks in case of merging or
1140 * replacing. If new lock(s) need to be inserted all modifications are
1141 * done below this, so it's safe yet to bail out.
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001142 */
1143 error = -ENOLCK; /* "no luck" */
1144 if (right && left == right && !new_fl2)
1145 goto out;
1146
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 error = 0;
1148 if (!added) {
Trond Myklebustf475ae92006-06-29 16:38:32 -04001149 if (request->fl_type == F_UNLCK) {
1150 if (request->fl_flags & FL_EXISTS)
1151 error = -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -04001153 }
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001154
1155 if (!new_fl) {
1156 error = -ENOLCK;
1157 goto out;
1158 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 locks_copy_lock(new_fl, request);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001160 locks_insert_lock_ctx(new_fl, &fl->fl_list);
Jeff Layton2e2f756f2015-02-17 17:08:23 -05001161 fl = new_fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 new_fl = NULL;
1163 }
1164 if (right) {
1165 if (left == right) {
1166 /* The new lock breaks the old one in two pieces,
1167 * so we have to use the second new lock.
1168 */
1169 left = new_fl2;
1170 new_fl2 = NULL;
1171 locks_copy_lock(left, right);
Jeff Laytone084c1b2015-02-16 14:32:03 -05001172 locks_insert_lock_ctx(left, &fl->fl_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 }
1174 right->fl_start = request->fl_end + 1;
1175 locks_wake_up_blocks(right);
1176 }
1177 if (left) {
1178 left->fl_end = request->fl_start - 1;
1179 locks_wake_up_blocks(left);
1180 }
1181 out:
Jeff Layton6109c852015-01-16 15:05:57 -05001182 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001183 percpu_up_read_preempt_enable(&file_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 /*
1185 * Free any unused locks.
1186 */
1187 if (new_fl)
1188 locks_free_lock(new_fl);
1189 if (new_fl2)
1190 locks_free_lock(new_fl2);
Jeff Laytoned9814d2014-08-11 14:20:31 -04001191 locks_dispose_list(&dispose);
Jeff Layton18909102016-01-06 21:26:10 -05001192 trace_posix_lock_inode(inode, request, error);
1193
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 return error;
1195}
1196
1197/**
1198 * posix_lock_file - Apply a POSIX-style lock to a file
1199 * @filp: The file to apply the lock to
1200 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05001201 * @conflock: Place to return a copy of the conflicting lock, if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 *
1203 * Add a POSIX style lock to a file.
1204 * We merge adjacent & overlapping locks whenever possible.
1205 * POSIX locks are sorted by owner task, then by starting address
Trond Myklebustf475ae92006-06-29 16:38:32 -04001206 *
1207 * Note that if called with an FL_EXISTS argument, the caller may determine
1208 * whether or not a lock was successfully freed by testing the return
1209 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 */
Marc Eshel150b3932007-01-18 16:15:35 -05001211int posix_lock_file(struct file *filp, struct file_lock *fl,
Andy Adamson5842add2006-03-26 01:37:26 -08001212 struct file_lock *conflock)
1213{
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001214 return posix_lock_inode(file_inode(filp), fl, conflock);
Andy Adamson5842add2006-03-26 01:37:26 -08001215}
Marc Eshel150b3932007-01-18 16:15:35 -05001216EXPORT_SYMBOL(posix_lock_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217
1218/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001219 * posix_lock_inode_wait - Apply a POSIX-style lock to a file
1220 * @inode: inode of file to which lock request should be applied
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 * @fl: The lock to be applied
1222 *
Benjamin Coddington616fb382015-10-22 13:38:15 -04001223 * Apply a POSIX style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001225static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226{
1227 int error;
1228 might_sleep ();
1229 for (;;) {
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001230 error = posix_lock_inode(inode, fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001231 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232 break;
1233 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1234 if (!error)
1235 continue;
1236
1237 locks_delete_block(fl);
1238 break;
1239 }
1240 return error;
1241}
Jeff Layton29d01b22015-07-11 06:43:02 -04001242
Jeff Layton9e8925b2015-11-16 09:49:34 -05001243#ifdef CONFIG_MANDATORY_FILE_LOCKING
Jeff Layton29d01b22015-07-11 06:43:02 -04001244/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 * locks_mandatory_locked - Check for an active lock
Jeff Laytond7a06982014-03-10 09:54:15 -04001246 * @file: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 *
1248 * Searches the inode's list of locks to find any POSIX locks which conflict.
1249 * This function is called from locks_verify_locked() only.
1250 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001251int locks_mandatory_locked(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252{
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001253 int ret;
Jeff Laytond7a06982014-03-10 09:54:15 -04001254 struct inode *inode = file_inode(file);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001255 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 struct file_lock *fl;
1257
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001258 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001259 if (!ctx || list_empty_careful(&ctx->flc_posix))
1260 return 0;
1261
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 /*
1263 * Search the lock list for this inode for any POSIX locks.
1264 */
Jeff Layton6109c852015-01-16 15:05:57 -05001265 spin_lock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001266 ret = 0;
1267 list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001268 if (fl->fl_owner != current->files &&
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001269 fl->fl_owner != file) {
1270 ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 break;
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001272 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 }
Jeff Layton6109c852015-01-16 15:05:57 -05001274 spin_unlock(&ctx->flc_lock);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05001275 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276}
1277
1278/**
1279 * locks_mandatory_area - Check for a conflicting lock
Christoph Hellwigacc15572015-12-03 12:59:49 +01001280 * @inode: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 * @filp: how the file was opened (if it was)
Christoph Hellwigacc15572015-12-03 12:59:49 +01001282 * @start: first byte in the file to check
1283 * @end: lastbyte in the file to check
1284 * @type: %F_WRLCK for a write lock, else %F_RDLCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 *
1286 * Searches the inode's list of locks to find any POSIX locks which conflict.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 */
Christoph Hellwigacc15572015-12-03 12:59:49 +01001288int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
1289 loff_t end, unsigned char type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290{
1291 struct file_lock fl;
1292 int error;
Jeff Layton29723ad2014-03-10 09:54:19 -04001293 bool sleep = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294
1295 locks_init_lock(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 fl.fl_pid = current->tgid;
1297 fl.fl_file = filp;
1298 fl.fl_flags = FL_POSIX | FL_ACCESS;
1299 if (filp && !(filp->f_flags & O_NONBLOCK))
Jeff Layton29723ad2014-03-10 09:54:19 -04001300 sleep = true;
Christoph Hellwigacc15572015-12-03 12:59:49 +01001301 fl.fl_type = type;
1302 fl.fl_start = start;
1303 fl.fl_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304
1305 for (;;) {
Jeff Layton29723ad2014-03-10 09:54:19 -04001306 if (filp) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001307 fl.fl_owner = filp;
Jeff Layton29723ad2014-03-10 09:54:19 -04001308 fl.fl_flags &= ~FL_SLEEP;
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001309 error = posix_lock_inode(inode, &fl, NULL);
Jeff Layton29723ad2014-03-10 09:54:19 -04001310 if (!error)
1311 break;
1312 }
1313
1314 if (sleep)
1315 fl.fl_flags |= FL_SLEEP;
1316 fl.fl_owner = current->files;
Jeff Laytonb4d629a2016-01-07 18:27:42 -05001317 error = posix_lock_inode(inode, &fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001318 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 break;
1320 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1321 if (!error) {
1322 /*
1323 * If we've been sleeping someone might have
1324 * changed the permissions behind our back.
1325 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07001326 if (__mandatory_lock(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 continue;
1328 }
1329
1330 locks_delete_block(&fl);
1331 break;
1332 }
1333
1334 return error;
1335}
1336
1337EXPORT_SYMBOL(locks_mandatory_area);
Jeff Layton9e8925b2015-11-16 09:49:34 -05001338#endif /* CONFIG_MANDATORY_FILE_LOCKING */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
J. Bruce Fields778fc542011-07-26 18:25:49 -04001340static void lease_clear_pending(struct file_lock *fl, int arg)
1341{
1342 switch (arg) {
1343 case F_UNLCK:
1344 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1345 /* fall through: */
1346 case F_RDLCK:
1347 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1348 }
1349}
1350
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351/* We already had a lease on this file; just change its type */
Jeff Layton7448cc32015-01-16 15:05:57 -05001352int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 int error = assign_type(fl, arg);
1355
1356 if (error)
1357 return error;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001358 lease_clear_pending(fl, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 locks_wake_up_blocks(fl);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001360 if (arg == F_UNLCK) {
1361 struct file *filp = fl->fl_file;
1362
1363 f_delown(filp);
1364 filp->f_owner.signum = 0;
J. Bruce Fields96d6d592012-07-27 16:18:00 -04001365 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1366 if (fl->fl_fasync != NULL) {
1367 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1368 fl->fl_fasync = NULL;
1369 }
Jeff Laytone084c1b2015-02-16 14:32:03 -05001370 locks_delete_lock_ctx(fl, dispose);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001371 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 return 0;
1373}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374EXPORT_SYMBOL(lease_modify);
1375
J. Bruce Fields778fc542011-07-26 18:25:49 -04001376static bool past_time(unsigned long then)
1377{
1378 if (!then)
1379 /* 0 is a special value meaning "this never expires": */
1380 return false;
1381 return time_after(jiffies, then);
1382}
1383
Jeff Laytonc45198e2014-09-01 07:12:07 -04001384static void time_out_leases(struct inode *inode, struct list_head *dispose)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385{
Jeff Layton8634b512015-01-16 15:05:55 -05001386 struct file_lock_context *ctx = inode->i_flctx;
1387 struct file_lock *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388
Jeff Layton6109c852015-01-16 15:05:57 -05001389 lockdep_assert_held(&ctx->flc_lock);
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001390
Jeff Layton8634b512015-01-16 15:05:55 -05001391 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001392 trace_time_out_leases(inode, fl);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001393 if (past_time(fl->fl_downgrade_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001394 lease_modify(fl, F_RDLCK, dispose);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001395 if (past_time(fl->fl_break_time))
Jeff Layton7448cc32015-01-16 15:05:57 -05001396 lease_modify(fl, F_UNLCK, dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 }
1398}
1399
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001400static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1401{
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001402 if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
1403 return false;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001404 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1405 return false;
1406 return locks_conflict(breaker, lease);
1407}
1408
Jeff Layton03d12dd2014-09-01 14:53:41 -04001409static bool
1410any_leases_conflict(struct inode *inode, struct file_lock *breaker)
1411{
Jeff Layton8634b512015-01-16 15:05:55 -05001412 struct file_lock_context *ctx = inode->i_flctx;
Jeff Layton03d12dd2014-09-01 14:53:41 -04001413 struct file_lock *fl;
1414
Jeff Layton6109c852015-01-16 15:05:57 -05001415 lockdep_assert_held(&ctx->flc_lock);
Jeff Layton03d12dd2014-09-01 14:53:41 -04001416
Jeff Layton8634b512015-01-16 15:05:55 -05001417 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Jeff Layton03d12dd2014-09-01 14:53:41 -04001418 if (leases_conflict(fl, breaker))
1419 return true;
1420 }
1421 return false;
1422}
1423
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424/**
1425 * __break_lease - revoke all outstanding leases on file
1426 * @inode: the inode of the file to return
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001427 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1428 * break all leases
1429 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1430 * only delegations
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 *
david m. richter87250dd2007-05-09 16:10:27 -04001432 * break_lease (inlined for speed) has checked there already is at least
1433 * some kind of lock (maybe a lease) on this file. Leases are broken on
1434 * a call to open() or truncate(). This function can sleep unless you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435 * specified %O_NONBLOCK to your open().
1436 */
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001437int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438{
J. Bruce Fields778fc542011-07-26 18:25:49 -04001439 int error = 0;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001440 struct file_lock_context *ctx;
Yan, Zhenga9011252015-03-27 10:34:20 +08001441 struct file_lock *new_fl, *fl, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 unsigned long break_time;
Al Viro8737c932009-12-24 06:47:55 -05001443 int want_write = (mode & O_ACCMODE) != O_RDONLY;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001444 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445
Al Viro8737c932009-12-24 06:47:55 -05001446 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001447 if (IS_ERR(new_fl))
1448 return PTR_ERR(new_fl);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001449 new_fl->fl_flags = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450
Jeff Layton8634b512015-01-16 15:05:55 -05001451 /* typically we will check that ctx is non-NULL before calling */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001452 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001453 if (!ctx) {
1454 WARN_ON_ONCE(1);
1455 return error;
1456 }
1457
Peter Zijlstra87709e22016-05-30 16:48:35 +02001458 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001459 spin_lock(&ctx->flc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460
Jeff Laytonc45198e2014-09-01 07:12:07 -04001461 time_out_leases(inode, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
Jeff Layton03d12dd2014-09-01 14:53:41 -04001463 if (!any_leases_conflict(inode, new_fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001464 goto out;
1465
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466 break_time = 0;
1467 if (lease_break_time > 0) {
1468 break_time = jiffies + lease_break_time * HZ;
1469 if (break_time == 0)
1470 break_time++; /* so that 0 means no break time */
1471 }
1472
Yan, Zhenga9011252015-03-27 10:34:20 +08001473 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001474 if (!leases_conflict(fl, new_fl))
1475 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001476 if (want_write) {
1477 if (fl->fl_flags & FL_UNLOCK_PENDING)
1478 continue;
1479 fl->fl_flags |= FL_UNLOCK_PENDING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 fl->fl_break_time = break_time;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001481 } else {
Jeff Layton8634b512015-01-16 15:05:55 -05001482 if (lease_breaking(fl))
J. Bruce Fields778fc542011-07-26 18:25:49 -04001483 continue;
1484 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1485 fl->fl_downgrade_time = break_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486 }
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001487 if (fl->fl_lmops->lm_break(fl))
Jeff Laytone084c1b2015-02-16 14:32:03 -05001488 locks_delete_lock_ctx(fl, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 }
1490
Jeff Layton8634b512015-01-16 15:05:55 -05001491 if (list_empty(&ctx->flc_lease))
Jeff Layton4d01b7f2014-09-01 15:06:54 -04001492 goto out;
1493
Jeff Layton843c6b22014-09-01 14:27:43 -04001494 if (mode & O_NONBLOCK) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001495 trace_break_lease_noblock(inode, new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 error = -EWOULDBLOCK;
1497 goto out;
1498 }
1499
1500restart:
Jeff Layton8634b512015-01-16 15:05:55 -05001501 fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
1502 break_time = fl->fl_break_time;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001503 if (break_time != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 break_time -= jiffies;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001505 if (break_time == 0)
1506 break_time++;
Jeff Layton8634b512015-01-16 15:05:55 -05001507 locks_insert_block(fl, new_fl);
Jeff Layton62af4f12014-05-09 14:13:05 -04001508 trace_break_lease_block(inode, new_fl);
Jeff Layton6109c852015-01-16 15:05:57 -05001509 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001510 percpu_up_read_preempt_enable(&file_rwsem);
Peter Zijlstraaba37662015-06-22 14:16:33 +02001511
Jeff Laytonc45198e2014-09-01 07:12:07 -04001512 locks_dispose_list(&dispose);
Matthew Wilcox4321e012008-01-14 21:28:30 -07001513 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1514 !new_fl->fl_next, break_time);
Peter Zijlstraaba37662015-06-22 14:16:33 +02001515
Peter Zijlstra87709e22016-05-30 16:48:35 +02001516 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001517 spin_lock(&ctx->flc_lock);
Jeff Layton62af4f12014-05-09 14:13:05 -04001518 trace_break_lease_unblock(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001519 locks_delete_block(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001520 if (error >= 0) {
J. Bruce Fields778fc542011-07-26 18:25:49 -04001521 /*
1522 * Wait for the next conflicting lease that has not been
1523 * broken yet
1524 */
Jeff Layton03d12dd2014-09-01 14:53:41 -04001525 if (error == 0)
1526 time_out_leases(inode, &dispose);
1527 if (any_leases_conflict(inode, new_fl))
1528 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529 error = 0;
1530 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531out:
Jeff Layton6109c852015-01-16 15:05:57 -05001532 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001533 percpu_up_read_preempt_enable(&file_rwsem);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001534 locks_dispose_list(&dispose);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001535 locks_free_lock(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 return error;
1537}
1538
1539EXPORT_SYMBOL(__break_lease);
1540
1541/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001542 * lease_get_mtime - get the last modified time of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 * @inode: the inode
1544 * @time: pointer to a timespec which will contain the last modified time
1545 *
1546 * This is to force NFS clients to flush their caches for files with
1547 * exclusive leases. The justification is that if someone has an
Randy Dunlapa6b91912008-03-19 17:01:00 -07001548 * exclusive lease, then they could be modifying it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549 */
1550void lease_get_mtime(struct inode *inode, struct timespec *time)
1551{
Jeff Laytonbfe86022014-08-22 10:18:44 -04001552 bool has_lease = false;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001553 struct file_lock_context *ctx;
Jeff Layton8634b512015-01-16 15:05:55 -05001554 struct file_lock *fl;
Jeff Laytonbfe86022014-08-22 10:18:44 -04001555
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001556 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001557 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001558 spin_lock(&ctx->flc_lock);
Geliang Tang8ace5df2015-11-18 21:40:33 +08001559 fl = list_first_entry_or_null(&ctx->flc_lease,
1560 struct file_lock, fl_list);
1561 if (fl && (fl->fl_type == F_WRLCK))
1562 has_lease = true;
Jeff Layton6109c852015-01-16 15:05:57 -05001563 spin_unlock(&ctx->flc_lock);
Jeff Laytonbfe86022014-08-22 10:18:44 -04001564 }
1565
1566 if (has_lease)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567 *time = current_fs_time(inode->i_sb);
1568 else
1569 *time = inode->i_mtime;
1570}
1571
1572EXPORT_SYMBOL(lease_get_mtime);
1573
1574/**
1575 * fcntl_getlease - Enquire what lease is currently active
1576 * @filp: the file
1577 *
1578 * The value returned by this function will be one of
1579 * (if no lease break is pending):
1580 *
1581 * %F_RDLCK to indicate a shared lease is held.
1582 *
1583 * %F_WRLCK to indicate an exclusive lease is held.
1584 *
1585 * %F_UNLCK to indicate no lease is held.
1586 *
1587 * (if a lease break is pending):
1588 *
1589 * %F_RDLCK to indicate an exclusive lease needs to be
1590 * changed to a shared lease (or removed).
1591 *
1592 * %F_UNLCK to indicate the lease needs to be removed.
1593 *
1594 * XXX: sfr & willy disagree over whether F_INPROGRESS
1595 * should be returned to userspace.
1596 */
1597int fcntl_getlease(struct file *filp)
1598{
1599 struct file_lock *fl;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001600 struct inode *inode = file_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001601 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001602 int type = F_UNLCK;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001603 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001605 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001606 if (ctx && !list_empty_careful(&ctx->flc_lease)) {
Jeff Layton6109c852015-01-16 15:05:57 -05001607 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001608 time_out_leases(file_inode(filp), &dispose);
1609 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
1610 if (fl->fl_file != filp)
1611 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001612 type = target_leasetype(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613 break;
1614 }
Jeff Layton6109c852015-01-16 15:05:57 -05001615 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001616 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001618 return type;
1619}
1620
Jeff Layton24cbe782014-02-03 12:13:06 -05001621/**
1622 * check_conflicting_open - see if the given dentry points to a file that has
1623 * an existing open that would conflict with the
1624 * desired lease.
1625 * @dentry: dentry to check
1626 * @arg: type of lease that we're trying to acquire
Randy Dunlap7fadc592015-08-09 18:43:17 -07001627 * @flags: current lock flags
Jeff Layton24cbe782014-02-03 12:13:06 -05001628 *
1629 * Check to see if there's an existing open fd on this file that would
1630 * conflict with the lease we're trying to set.
1631 */
1632static int
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001633check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
Jeff Layton24cbe782014-02-03 12:13:06 -05001634{
1635 int ret = 0;
1636 struct inode *inode = dentry->d_inode;
1637
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001638 if (flags & FL_LAYOUT)
1639 return 0;
1640
Jeff Layton24cbe782014-02-03 12:13:06 -05001641 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1642 return -EAGAIN;
1643
1644 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1645 (atomic_read(&inode->i_count) > 1)))
1646 ret = -EAGAIN;
1647
1648 return ret;
1649}
1650
Jeff Laytone6f5c782014-08-22 10:40:25 -04001651static int
1652generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001653{
Jeff Layton8634b512015-01-16 15:05:55 -05001654 struct file_lock *fl, *my_fl = NULL, *lease;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001655 struct dentry *dentry = filp->f_path.dentry;
Miklos Szeredi6343a212016-07-01 14:56:07 +02001656 struct inode *inode = file_inode(filp);
Jeff Layton8634b512015-01-16 15:05:55 -05001657 struct file_lock_context *ctx;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001658 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001659 int error;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001660 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001661
J. Bruce Fields096657b2010-10-30 17:31:14 -04001662 lease = *flp;
Jeff Layton62af4f12014-05-09 14:13:05 -04001663 trace_generic_add_lease(inode, lease);
1664
Jeff Layton5c1c6692015-04-03 09:04:03 -04001665 /* Note that arg is never F_UNLCK here */
1666 ctx = locks_get_lock_context(inode, arg);
Jeff Layton8634b512015-01-16 15:05:55 -05001667 if (!ctx)
1668 return -ENOMEM;
1669
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001670 /*
1671 * In the delegation case we need mutual exclusion with
1672 * a number of operations that take the i_mutex. We trylock
1673 * because delegations are an optional optimization, and if
1674 * there's some chance of a conflict--we'd rather not
1675 * bother, maybe that's a sign this just isn't a good file to
1676 * hand out a delegation on.
1677 */
Al Viro59551022016-01-22 15:40:57 -05001678 if (is_deleg && !inode_trylock(inode))
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001679 return -EAGAIN;
1680
1681 if (is_deleg && arg == F_WRLCK) {
1682 /* Write delegations are not currently supported: */
Al Viro59551022016-01-22 15:40:57 -05001683 inode_unlock(inode);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001684 WARN_ON_ONCE(1);
1685 return -EINVAL;
1686 }
J. Bruce Fields096657b2010-10-30 17:31:14 -04001687
Peter Zijlstra87709e22016-05-30 16:48:35 +02001688 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001689 spin_lock(&ctx->flc_lock);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001690 time_out_leases(inode, &dispose);
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001691 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton24cbe782014-02-03 12:13:06 -05001692 if (error)
J. Bruce Fields096657b2010-10-30 17:31:14 -04001693 goto out;
Pavel Emelyanov85c59582007-09-20 12:45:02 +04001694
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695 /*
1696 * At this point, we know that if there is an exclusive
1697 * lease on this file, then we hold it on this filp
1698 * (otherwise our open of this file would have blocked).
1699 * And if we are trying to acquire an exclusive lease,
1700 * then the file is not open by anyone (including us)
1701 * except for this filp.
1702 */
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001703 error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001704 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001705 if (fl->fl_file == filp &&
1706 fl->fl_owner == lease->fl_owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001707 my_fl = fl;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001708 continue;
1709 }
Jeff Layton8634b512015-01-16 15:05:55 -05001710
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001711 /*
1712 * No exclusive leases if someone else has a lease on
1713 * this file:
1714 */
1715 if (arg == F_WRLCK)
1716 goto out;
1717 /*
1718 * Modifying our existing lease is OK, but no getting a
1719 * new lease if someone else is opening for write:
1720 */
1721 if (fl->fl_flags & FL_UNLOCK_PENDING)
1722 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723 }
1724
Jeff Layton8634b512015-01-16 15:05:55 -05001725 if (my_fl != NULL) {
Jeff Layton0164bf02015-03-04 17:34:32 -05001726 lease = my_fl;
1727 error = lease->fl_lmops->lm_change(lease, arg, &dispose);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001728 if (error)
1729 goto out;
1730 goto out_setup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731 }
1732
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 error = -EINVAL;
1734 if (!leases_enable)
1735 goto out;
1736
Jeff Laytone084c1b2015-02-16 14:32:03 -05001737 locks_insert_lock_ctx(lease, &ctx->flc_lease);
Jeff Layton24cbe782014-02-03 12:13:06 -05001738 /*
1739 * The check in break_lease() is lockless. It's possible for another
1740 * open to race in after we did the earlier check for a conflicting
1741 * open but before the lease was inserted. Check again for a
1742 * conflicting open and cancel the lease if there is one.
1743 *
1744 * We also add a barrier here to ensure that the insertion of the lock
1745 * precedes these checks.
1746 */
1747 smp_mb();
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001748 error = check_conflicting_open(dentry, arg, lease->fl_flags);
Jeff Layton8634b512015-01-16 15:05:55 -05001749 if (error) {
Jeff Laytone084c1b2015-02-16 14:32:03 -05001750 locks_unlink_lock_ctx(lease);
Jeff Layton8634b512015-01-16 15:05:55 -05001751 goto out;
1752 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001753
1754out_setup:
1755 if (lease->fl_lmops->lm_setup)
1756 lease->fl_lmops->lm_setup(lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757out:
Jeff Layton6109c852015-01-16 15:05:57 -05001758 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001759 percpu_up_read_preempt_enable(&file_rwsem);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001760 locks_dispose_list(&dispose);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001761 if (is_deleg)
Al Viro59551022016-01-22 15:40:57 -05001762 inode_unlock(inode);
Jeff Layton8634b512015-01-16 15:05:55 -05001763 if (!error && !my_fl)
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001764 *flp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765 return error;
1766}
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001767
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001768static int generic_delete_lease(struct file *filp, void *owner)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001769{
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001770 int error = -EAGAIN;
Jeff Layton8634b512015-01-16 15:05:55 -05001771 struct file_lock *fl, *victim = NULL;
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04001772 struct inode *inode = file_inode(filp);
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001773 struct file_lock_context *ctx;
Jeff Laytonc45198e2014-09-01 07:12:07 -04001774 LIST_HEAD(dispose);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001775
Dmitry Vyukov128a3782015-09-21 09:43:06 +02001776 ctx = smp_load_acquire(&inode->i_flctx);
Jeff Layton8634b512015-01-16 15:05:55 -05001777 if (!ctx) {
1778 trace_generic_delete_lease(inode, NULL);
1779 return error;
1780 }
1781
Peter Zijlstra87709e22016-05-30 16:48:35 +02001782 percpu_down_read_preempt_disable(&file_rwsem);
Jeff Layton6109c852015-01-16 15:05:57 -05001783 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05001784 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001785 if (fl->fl_file == filp &&
1786 fl->fl_owner == owner) {
Jeff Layton8634b512015-01-16 15:05:55 -05001787 victim = fl;
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001788 break;
Jeff Layton8634b512015-01-16 15:05:55 -05001789 }
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001790 }
Jeff Laytona9b1b452015-03-14 09:45:35 -04001791 trace_generic_delete_lease(inode, victim);
Jeff Layton8634b512015-01-16 15:05:55 -05001792 if (victim)
Jeff Layton7448cc32015-01-16 15:05:57 -05001793 error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05001794 spin_unlock(&ctx->flc_lock);
Peter Zijlstra87709e22016-05-30 16:48:35 +02001795 percpu_up_read_preempt_enable(&file_rwsem);
Jeff Laytonc45198e2014-09-01 07:12:07 -04001796 locks_dispose_list(&dispose);
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001797 return error;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001798}
1799
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800/**
1801 * generic_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001802 * @filp: file pointer
1803 * @arg: type of lease to obtain
1804 * @flp: input - file_lock to use, output - file_lock inserted
1805 * @priv: private data for lm_setup (may be NULL if lm_setup
1806 * doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 *
1808 * The (input) flp->fl_lmops->lm_break function is required
1809 * by break_lease().
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001811int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1812 void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813{
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04001814 struct inode *inode = file_inode(filp);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001815 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001816
Eric W. Biederman8e96e3b2012-03-03 21:17:15 -08001817 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001818 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 if (!S_ISREG(inode->i_mode))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001820 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 error = security_file_lock(filp, arg);
1822 if (error)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001823 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001825 switch (arg) {
1826 case F_UNLCK:
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001827 return generic_delete_lease(filp, *priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001828 case F_RDLCK:
1829 case F_WRLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001830 if (!(*flp)->fl_lmops->lm_break) {
1831 WARN_ON_ONCE(1);
1832 return -ENOLCK;
1833 }
Christoph Hellwig11afe9f2015-01-21 19:17:03 +01001834
Jeff Laytone6f5c782014-08-22 10:40:25 -04001835 return generic_add_lease(filp, arg, flp, priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001836 default:
Dave Jones8d657eb2012-07-13 13:35:36 -04001837 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001839}
Christoph Hellwig0af1a452007-07-31 00:39:22 -07001840EXPORT_SYMBOL(generic_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841
Arnd Bergmannb89f4322010-09-18 15:09:31 +02001842/**
Jeff Laytone51673a2014-08-22 18:13:28 -04001843 * vfs_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001844 * @filp: file pointer
1845 * @arg: type of lease to obtain
1846 * @lease: file_lock to use when adding a lease
1847 * @priv: private info for lm_setup when adding a lease (may be
1848 * NULL if lm_setup doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849 *
Jeff Laytone51673a2014-08-22 18:13:28 -04001850 * Call this to establish a lease on the file. The "lease" argument is not
1851 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1852 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1853 * if not, this function will return -ENOLCK (and generate a scary-looking
1854 * stack trace).
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001855 *
1856 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1857 * may be NULL if the lm_setup operation doesn't require it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001859int
1860vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001862 if (filp->f_op->setlease)
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001863 return filp->f_op->setlease(filp, arg, lease, priv);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001864 else
Jeff Laytonf82b4b62014-08-22 18:50:48 -04001865 return generic_setlease(filp, arg, lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866}
J. Bruce Fieldsa9933ce2007-06-07 17:09:49 -04001867EXPORT_SYMBOL_GPL(vfs_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001869static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001871 struct file_lock *fl;
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001872 struct fasync_struct *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 int error;
1874
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001875 fl = lease_alloc(filp, arg);
1876 if (IS_ERR(fl))
1877 return PTR_ERR(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001879 new = fasync_alloc();
1880 if (!new) {
1881 locks_free_lock(fl);
1882 return -ENOMEM;
1883 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001884 new->fa_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001886 error = vfs_setlease(filp, arg, &fl, (void **)&new);
Jeff Layton2dfb9282014-08-11 18:14:12 -04001887 if (fl)
1888 locks_free_lock(fl);
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001889 if (new)
1890 fasync_free(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 return error;
1892}
1893
1894/**
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001895 * fcntl_setlease - sets a lease on an open file
1896 * @fd: open file descriptor
1897 * @filp: file pointer
1898 * @arg: type of lease to obtain
1899 *
1900 * Call this fcntl to establish a lease on the file.
1901 * Note that you also need to call %F_SETSIG to
1902 * receive a signal when the lease is broken.
1903 */
1904int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1905{
1906 if (arg == F_UNLCK)
Christoph Hellwig2ab99ee2015-01-21 19:14:02 +01001907 return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001908 return do_fcntl_add_lease(fd, filp, arg);
1909}
1910
1911/**
Jeff Layton29d01b22015-07-11 06:43:02 -04001912 * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
1913 * @inode: inode of the file to apply to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914 * @fl: The lock to be applied
1915 *
Jeff Layton29d01b22015-07-11 06:43:02 -04001916 * Apply a FLOCK style lock request to an inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917 */
Benjamin Coddington616fb382015-10-22 13:38:15 -04001918static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919{
1920 int error;
1921 might_sleep();
1922 for (;;) {
Jeff Layton29d01b22015-07-11 06:43:02 -04001923 error = flock_lock_inode(inode, fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001924 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925 break;
1926 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1927 if (!error)
1928 continue;
1929
1930 locks_delete_block(fl);
1931 break;
1932 }
1933 return error;
1934}
1935
Jeff Layton29d01b22015-07-11 06:43:02 -04001936/**
Benjamin Coddingtone55c34a2015-10-22 13:38:13 -04001937 * locks_lock_inode_wait - Apply a lock to an inode
1938 * @inode: inode of the file to apply to
1939 * @fl: The lock to be applied
1940 *
1941 * Apply a POSIX or FLOCK style lock request to an inode.
1942 */
1943int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
1944{
1945 int res = 0;
1946 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
1947 case FL_POSIX:
1948 res = posix_lock_inode_wait(inode, fl);
1949 break;
1950 case FL_FLOCK:
1951 res = flock_lock_inode_wait(inode, fl);
1952 break;
1953 default:
1954 BUG();
1955 }
1956 return res;
1957}
1958EXPORT_SYMBOL(locks_lock_inode_wait);
1959
1960/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001961 * sys_flock: - flock() system call.
1962 * @fd: the file descriptor to lock.
1963 * @cmd: the type of lock to apply.
1964 *
1965 * Apply a %FL_FLOCK style lock to an open file descriptor.
1966 * The @cmd can be one of
1967 *
1968 * %LOCK_SH -- a shared lock.
1969 *
1970 * %LOCK_EX -- an exclusive lock.
1971 *
1972 * %LOCK_UN -- remove an existing lock.
1973 *
1974 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1975 *
1976 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1977 * processes read and write access respectively.
1978 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001979SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980{
Al Viro2903ff02012-08-28 12:52:22 -04001981 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982 struct file_lock *lock;
1983 int can_sleep, unlock;
1984 int error;
1985
1986 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001987 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988 goto out;
1989
1990 can_sleep = !(cmd & LOCK_NB);
1991 cmd &= ~LOCK_NB;
1992 unlock = (cmd == LOCK_UN);
1993
Al Viroaeb5d722008-09-02 15:28:45 -04001994 if (!unlock && !(cmd & LOCK_MAND) &&
Al Viro2903ff02012-08-28 12:52:22 -04001995 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996 goto out_putf;
1997
Jeff Layton6e129d002014-09-04 10:25:06 -04001998 lock = flock_make_lock(f.file, cmd);
1999 if (IS_ERR(lock)) {
2000 error = PTR_ERR(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001 goto out_putf;
Jeff Layton6e129d002014-09-04 10:25:06 -04002002 }
2003
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004 if (can_sleep)
2005 lock->fl_flags |= FL_SLEEP;
2006
Al Viro2903ff02012-08-28 12:52:22 -04002007 error = security_file_lock(f.file, lock->fl_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 if (error)
2009 goto out_free;
2010
Al Viro72c2d532013-09-22 16:27:52 -04002011 if (f.file->f_op->flock)
Al Viro2903ff02012-08-28 12:52:22 -04002012 error = f.file->f_op->flock(f.file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 (can_sleep) ? F_SETLKW : F_SETLK,
2014 lock);
2015 else
Benjamin Coddington4f656362015-10-22 13:38:14 -04002016 error = locks_lock_file_wait(f.file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002017
2018 out_free:
Trond Myklebust993dfa82006-03-31 02:30:55 -08002019 locks_free_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020
2021 out_putf:
Al Viro2903ff02012-08-28 12:52:22 -04002022 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 out:
2024 return error;
2025}
2026
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002027/**
2028 * vfs_test_lock - test file byte range lock
2029 * @filp: The file to test lock for
J. Bruce Fields6924c552007-05-11 16:22:50 -04002030 * @fl: The lock to test; also used to hold result
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002031 *
2032 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
2033 * setting conf->fl_type to something other than F_UNLCK.
2034 */
2035int vfs_test_lock(struct file *filp, struct file_lock *fl)
2036{
Al Viro72c2d532013-09-22 16:27:52 -04002037 if (filp->f_op->lock)
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002038 return filp->f_op->lock(filp, F_GETLK, fl);
2039 posix_test_lock(filp, fl);
2040 return 0;
2041}
2042EXPORT_SYMBOL_GPL(vfs_test_lock);
2043
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002044static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
2045{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002046 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002047#if BITS_PER_LONG == 32
2048 /*
2049 * Make sure we can represent the posix lock via
2050 * legacy 32bit flock.
2051 */
2052 if (fl->fl_start > OFFT_OFFSET_MAX)
2053 return -EOVERFLOW;
2054 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
2055 return -EOVERFLOW;
2056#endif
2057 flock->l_start = fl->fl_start;
2058 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2059 fl->fl_end - fl->fl_start + 1;
2060 flock->l_whence = 0;
J. Bruce Fields129a84d2007-05-10 18:38:43 -04002061 flock->l_type = fl->fl_type;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002062 return 0;
2063}
2064
2065#if BITS_PER_LONG == 32
2066static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
2067{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002068 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002069 flock->l_start = fl->fl_start;
2070 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
2071 fl->fl_end - fl->fl_start + 1;
2072 flock->l_whence = 0;
2073 flock->l_type = fl->fl_type;
2074}
2075#endif
2076
Linus Torvalds1da177e2005-04-16 15:20:36 -07002077/* Report the first existing lock that would conflict with l.
2078 * This implements the F_GETLK command of fcntl().
2079 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002080int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002082 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002083 struct flock flock;
2084 int error;
2085
2086 error = -EFAULT;
2087 if (copy_from_user(&flock, l, sizeof(flock)))
2088 goto out;
2089 error = -EINVAL;
2090 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2091 goto out;
2092
2093 error = flock_to_posix_lock(filp, &file_lock, &flock);
2094 if (error)
2095 goto out;
2096
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002097 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002098 error = -EINVAL;
2099 if (flock.l_pid != 0)
2100 goto out;
2101
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002102 cmd = F_GETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002103 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002104 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002105 }
2106
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002107 error = vfs_test_lock(filp, &file_lock);
2108 if (error)
2109 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002110
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002111 flock.l_type = file_lock.fl_type;
2112 if (file_lock.fl_type != F_UNLCK) {
2113 error = posix_lock_to_flock(&flock, &file_lock);
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05002114 if (error)
Kinglong Meef3282962014-08-22 10:18:43 -04002115 goto rel_priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002116 }
2117 error = -EFAULT;
2118 if (!copy_to_user(l, &flock, sizeof(flock)))
2119 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002120rel_priv:
2121 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002122out:
2123 return error;
2124}
2125
Marc Eshel7723ec92007-01-18 15:08:55 -05002126/**
2127 * vfs_lock_file - file byte range lock
2128 * @filp: The file to apply the lock to
2129 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2130 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05002131 * @conf: Place to return a copy of the conflicting lock, if found.
2132 *
2133 * A caller that doesn't care about the conflicting lock may pass NULL
2134 * as the final argument.
2135 *
2136 * If the filesystem defines a private ->lock() method, then @conf will
2137 * be left unchanged; so a caller that cares should initialize it to
2138 * some acceptable default.
Marc Eshel2beb6612006-12-05 23:31:28 -05002139 *
2140 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2141 * locks, the ->lock() interface may return asynchronously, before the lock has
2142 * been granted or denied by the underlying filesystem, if (and only if)
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002143 * lm_grant is set. Callers expecting ->lock() to return asynchronously
Marc Eshel2beb6612006-12-05 23:31:28 -05002144 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2145 * the request is for a blocking lock. When ->lock() does return asynchronously,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002146 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
Marc Eshel2beb6612006-12-05 23:31:28 -05002147 * request completes.
2148 * If the request is for non-blocking lock the file system should return
Miklos Szeredibde74e42008-07-25 01:48:57 -07002149 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2150 * with the result. If the request timed out the callback routine will return a
Marc Eshel2beb6612006-12-05 23:31:28 -05002151 * nonzero return code and the file system should release the lock. The file
2152 * system is also responsible to keep a corresponding posix lock when it
2153 * grants a lock so the VFS can find out which locks are locally held and do
2154 * the correct lock cleanup when required.
2155 * The underlying filesystem must not drop the kernel lock or call
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002156 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
Marc Eshel2beb6612006-12-05 23:31:28 -05002157 * return code.
Marc Eshel7723ec92007-01-18 15:08:55 -05002158 */
Marc Eshel150b3932007-01-18 16:15:35 -05002159int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
Marc Eshel7723ec92007-01-18 15:08:55 -05002160{
Al Viro72c2d532013-09-22 16:27:52 -04002161 if (filp->f_op->lock)
Marc Eshel7723ec92007-01-18 15:08:55 -05002162 return filp->f_op->lock(filp, cmd, fl);
2163 else
Marc Eshel150b3932007-01-18 16:15:35 -05002164 return posix_lock_file(filp, fl, conf);
Marc Eshel7723ec92007-01-18 15:08:55 -05002165}
2166EXPORT_SYMBOL_GPL(vfs_lock_file);
2167
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002168static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2169 struct file_lock *fl)
2170{
2171 int error;
2172
2173 error = security_file_lock(filp, fl->fl_type);
2174 if (error)
2175 return error;
2176
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002177 for (;;) {
2178 error = vfs_lock_file(filp, cmd, fl, NULL);
2179 if (error != FILE_LOCK_DEFERRED)
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002180 break;
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002181 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2182 if (!error)
2183 continue;
2184
2185 locks_delete_block(fl);
2186 break;
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002187 }
2188
2189 return error;
2190}
2191
Benjamin Coddington6ca7d912015-10-15 09:07:07 -04002192/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002193static int
2194check_fmode_for_setlk(struct file_lock *fl)
2195{
2196 switch (fl->fl_type) {
2197 case F_RDLCK:
2198 if (!(fl->fl_file->f_mode & FMODE_READ))
2199 return -EBADF;
2200 break;
2201 case F_WRLCK:
2202 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2203 return -EBADF;
2204 }
2205 return 0;
2206}
2207
Linus Torvalds1da177e2005-04-16 15:20:36 -07002208/* Apply the lock described by l to an open file descriptor.
2209 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2210 */
Peter Staubachc2936212005-07-27 11:45:09 -07002211int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2212 struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213{
2214 struct file_lock *file_lock = locks_alloc_lock();
2215 struct flock flock;
2216 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002217 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002218 int error;
2219
2220 if (file_lock == NULL)
2221 return -ENOLCK;
2222
Jeff Layton18909102016-01-06 21:26:10 -05002223 inode = file_inode(filp);
2224
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225 /*
2226 * This might block, so we do it before checking the inode.
2227 */
2228 error = -EFAULT;
2229 if (copy_from_user(&flock, l, sizeof(flock)))
2230 goto out;
2231
Linus Torvalds1da177e2005-04-16 15:20:36 -07002232 /* Don't allow mandatory locks on files that may be memory mapped
2233 * and shared.
2234 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002235 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002236 error = -EAGAIN;
2237 goto out;
2238 }
2239
2240 error = flock_to_posix_lock(filp, file_lock, &flock);
2241 if (error)
2242 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002243
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002244 error = check_fmode_for_setlk(file_lock);
2245 if (error)
2246 goto out;
2247
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002248 /*
2249 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002250 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002251 */
2252 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002253 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002254 error = -EINVAL;
2255 if (flock.l_pid != 0)
2256 goto out;
2257
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002258 cmd = F_SETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002259 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002260 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002261 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002262 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002263 error = -EINVAL;
2264 if (flock.l_pid != 0)
2265 goto out;
2266
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002267 cmd = F_SETLKW;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002268 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002269 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002270 /* Fallthrough */
2271 case F_SETLKW:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272 file_lock->fl_flags |= FL_SLEEP;
2273 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002274
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002275 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276
Peter Staubachc2936212005-07-27 11:45:09 -07002277 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002278 * Attempt to detect a close/fcntl race and recover by releasing the
2279 * lock that was just acquired. There is no need to do that when we're
2280 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002281 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002282 if (!error && file_lock->fl_type != F_UNLCK &&
2283 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002284 /*
2285 * We need that spin_lock here - it prevents reordering between
2286 * update of i_flctx->flc_posix and check for it done in
2287 * close(). rcu_read_lock() wouldn't do.
2288 */
2289 spin_lock(&current->files->file_lock);
2290 f = fcheck(fd);
2291 spin_unlock(&current->files->file_lock);
2292 if (f != filp) {
2293 file_lock->fl_type = F_UNLCK;
2294 error = do_lock_file_wait(filp, cmd, file_lock);
2295 WARN_ON_ONCE(error);
2296 error = -EBADF;
2297 }
Peter Staubachc2936212005-07-27 11:45:09 -07002298 }
Peter Staubachc2936212005-07-27 11:45:09 -07002299out:
Jeff Layton18909102016-01-06 21:26:10 -05002300 trace_fcntl_setlk(inode, file_lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301 locks_free_lock(file_lock);
2302 return error;
2303}
2304
2305#if BITS_PER_LONG == 32
2306/* Report the first existing lock that would conflict with l.
2307 * This implements the F_GETLK command of fcntl().
2308 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002309int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002311 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312 struct flock64 flock;
2313 int error;
2314
2315 error = -EFAULT;
2316 if (copy_from_user(&flock, l, sizeof(flock)))
2317 goto out;
2318 error = -EINVAL;
2319 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2320 goto out;
2321
2322 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2323 if (error)
2324 goto out;
2325
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002326 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002327 error = -EINVAL;
2328 if (flock.l_pid != 0)
2329 goto out;
2330
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002331 cmd = F_GETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002332 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002333 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002334 }
2335
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002336 error = vfs_test_lock(filp, &file_lock);
2337 if (error)
2338 goto out;
2339
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002340 flock.l_type = file_lock.fl_type;
2341 if (file_lock.fl_type != F_UNLCK)
2342 posix_lock_to_flock64(&flock, &file_lock);
2343
Linus Torvalds1da177e2005-04-16 15:20:36 -07002344 error = -EFAULT;
2345 if (!copy_to_user(l, &flock, sizeof(flock)))
2346 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002347
2348 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349out:
2350 return error;
2351}
2352
2353/* Apply the lock described by l to an open file descriptor.
2354 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2355 */
Peter Staubachc2936212005-07-27 11:45:09 -07002356int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2357 struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358{
2359 struct file_lock *file_lock = locks_alloc_lock();
2360 struct flock64 flock;
2361 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002362 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002363 int error;
2364
2365 if (file_lock == NULL)
2366 return -ENOLCK;
2367
2368 /*
2369 * This might block, so we do it before checking the inode.
2370 */
2371 error = -EFAULT;
2372 if (copy_from_user(&flock, l, sizeof(flock)))
2373 goto out;
2374
Al Viro496ad9a2013-01-23 17:07:38 -05002375 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002376
2377 /* Don't allow mandatory locks on files that may be memory mapped
2378 * and shared.
2379 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002380 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002381 error = -EAGAIN;
2382 goto out;
2383 }
2384
2385 error = flock64_to_posix_lock(filp, file_lock, &flock);
2386 if (error)
2387 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002388
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002389 error = check_fmode_for_setlk(file_lock);
2390 if (error)
2391 goto out;
2392
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002393 /*
2394 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002395 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002396 */
2397 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002398 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002399 error = -EINVAL;
2400 if (flock.l_pid != 0)
2401 goto out;
2402
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002403 cmd = F_SETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002404 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002405 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002406 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002407 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002408 error = -EINVAL;
2409 if (flock.l_pid != 0)
2410 goto out;
2411
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002412 cmd = F_SETLKW64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002413 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002414 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002415 /* Fallthrough */
2416 case F_SETLKW64:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002417 file_lock->fl_flags |= FL_SLEEP;
2418 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002419
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002420 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002421
Peter Staubachc2936212005-07-27 11:45:09 -07002422 /*
Jeff Layton0752ba82016-01-08 07:30:43 -05002423 * Attempt to detect a close/fcntl race and recover by releasing the
2424 * lock that was just acquired. There is no need to do that when we're
2425 * unlocking though, or for OFD locks.
Peter Staubachc2936212005-07-27 11:45:09 -07002426 */
Jeff Layton0752ba82016-01-08 07:30:43 -05002427 if (!error && file_lock->fl_type != F_UNLCK &&
2428 !(file_lock->fl_flags & FL_OFDLCK)) {
Jeff Layton7f3697e2016-01-07 16:38:10 -05002429 /*
2430 * We need that spin_lock here - it prevents reordering between
2431 * update of i_flctx->flc_posix and check for it done in
2432 * close(). rcu_read_lock() wouldn't do.
2433 */
2434 spin_lock(&current->files->file_lock);
2435 f = fcheck(fd);
2436 spin_unlock(&current->files->file_lock);
2437 if (f != filp) {
2438 file_lock->fl_type = F_UNLCK;
2439 error = do_lock_file_wait(filp, cmd, file_lock);
2440 WARN_ON_ONCE(error);
2441 error = -EBADF;
2442 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002443 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002444out:
2445 locks_free_lock(file_lock);
2446 return error;
2447}
2448#endif /* BITS_PER_LONG == 32 */
2449
2450/*
2451 * This function is called when the file is being removed
2452 * from the task's fd array. POSIX locks belonging to this task
2453 * are deleted at this time.
2454 */
2455void locks_remove_posix(struct file *filp, fl_owner_t owner)
2456{
Jeff Layton18909102016-01-06 21:26:10 -05002457 int error;
Miklos Szerediff7b86b2006-06-23 02:05:11 -07002458 struct file_lock lock;
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002459 struct file_lock_context *ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002460
2461 /*
2462 * If there are no locks held on this file, we don't need to call
2463 * posix_lock_file(). Another process could be setting a lock on this
2464 * file at the same time, but we wouldn't remove that lock anyway.
2465 */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002466 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
Jeff Laytonbd61e0a2015-01-16 15:05:55 -05002467 if (!ctx || list_empty(&ctx->flc_posix))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468 return;
2469
2470 lock.fl_type = F_UNLCK;
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07002471 lock.fl_flags = FL_POSIX | FL_CLOSE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002472 lock.fl_start = 0;
2473 lock.fl_end = OFFSET_MAX;
2474 lock.fl_owner = owner;
2475 lock.fl_pid = current->tgid;
2476 lock.fl_file = filp;
2477 lock.fl_ops = NULL;
2478 lock.fl_lmops = NULL;
2479
Jeff Layton18909102016-01-06 21:26:10 -05002480 error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002481
Linus Torvalds1da177e2005-04-16 15:20:36 -07002482 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2483 lock.fl_ops->fl_release_private(&lock);
Jeff Layton18909102016-01-06 21:26:10 -05002484 trace_locks_remove_posix(file_inode(filp), &lock, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002485}
2486
2487EXPORT_SYMBOL(locks_remove_posix);
2488
Jeff Layton3d8e5602015-01-16 15:05:58 -05002489/* The i_flctx must be valid when calling into here */
Jeff Laytondd459bb2015-01-16 15:05:54 -05002490static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002491locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
Jeff Laytondd459bb2015-01-16 15:05:54 -05002492{
2493 struct file_lock fl = {
2494 .fl_owner = filp,
2495 .fl_pid = current->tgid,
2496 .fl_file = filp,
2497 .fl_flags = FL_FLOCK,
2498 .fl_type = F_UNLCK,
2499 .fl_end = OFFSET_MAX,
2500 };
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002501 struct inode *inode = file_inode(filp);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002502
Jeff Layton3d8e5602015-01-16 15:05:58 -05002503 if (list_empty(&flctx->flc_flock))
Jeff Laytondd459bb2015-01-16 15:05:54 -05002504 return;
2505
2506 if (filp->f_op->flock)
2507 filp->f_op->flock(filp, F_SETLKW, &fl);
2508 else
Jeff Laytonbcd7f782015-07-11 06:43:02 -04002509 flock_lock_inode(inode, &fl);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002510
2511 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2512 fl.fl_ops->fl_release_private(&fl);
2513}
2514
Jeff Layton3d8e5602015-01-16 15:05:58 -05002515/* The i_flctx must be valid when calling into here */
Jeff Layton8634b512015-01-16 15:05:55 -05002516static void
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002517locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
Jeff Layton8634b512015-01-16 15:05:55 -05002518{
Jeff Layton8634b512015-01-16 15:05:55 -05002519 struct file_lock *fl, *tmp;
2520 LIST_HEAD(dispose);
2521
Jeff Layton3d8e5602015-01-16 15:05:58 -05002522 if (list_empty(&ctx->flc_lease))
Jeff Layton8634b512015-01-16 15:05:55 -05002523 return;
2524
Jeff Layton6109c852015-01-16 15:05:57 -05002525 spin_lock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002526 list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
Jeff Laytonc4e136c2015-02-16 19:37:42 -05002527 if (filp == fl->fl_file)
2528 lease_modify(fl, F_UNLCK, &dispose);
Jeff Layton6109c852015-01-16 15:05:57 -05002529 spin_unlock(&ctx->flc_lock);
Jeff Layton8634b512015-01-16 15:05:55 -05002530 locks_dispose_list(&dispose);
2531}
2532
Linus Torvalds1da177e2005-04-16 15:20:36 -07002533/*
2534 * This function is called on the last close of an open file.
2535 */
Jeff Layton78ed8a12014-02-03 12:13:08 -05002536void locks_remove_file(struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002537{
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002538 struct file_lock_context *ctx;
2539
2540 ctx = smp_load_acquire(&file_inode(filp)->i_flctx);
2541 if (!ctx)
Jeff Layton3d8e5602015-01-16 15:05:58 -05002542 return;
2543
Jeff Laytondd459bb2015-01-16 15:05:54 -05002544 /* remove any OFD locks */
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002545 locks_remove_posix(filp, filp);
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002546
Jeff Laytondd459bb2015-01-16 15:05:54 -05002547 /* remove flock locks */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002548 locks_remove_flock(filp, ctx);
Jeff Laytondd459bb2015-01-16 15:05:54 -05002549
Jeff Layton8634b512015-01-16 15:05:55 -05002550 /* remove any leases */
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002551 locks_remove_lease(filp, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002552}
2553
2554/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002555 * posix_unblock_lock - stop waiting for a file lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07002556 * @waiter: the lock which was waiting
2557 *
2558 * lockd needs to block waiting for locks.
2559 */
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002560int
Jeff Laytonf891a292013-06-21 08:58:09 -04002561posix_unblock_lock(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002562{
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002563 int status = 0;
2564
Jeff Layton7b2296a2013-06-21 08:58:20 -04002565 spin_lock(&blocked_lock_lock);
J. Bruce Fields5996a292006-01-03 09:55:44 +01002566 if (waiter->fl_next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002567 __locks_delete_block(waiter);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002568 else
2569 status = -ENOENT;
Jeff Layton7b2296a2013-06-21 08:58:20 -04002570 spin_unlock(&blocked_lock_lock);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002571 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002572}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002573EXPORT_SYMBOL(posix_unblock_lock);
2574
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002575/**
2576 * vfs_cancel_lock - file byte range unblock lock
2577 * @filp: The file to apply the unblock to
2578 * @fl: The lock to be unblocked
2579 *
2580 * Used by lock managers to cancel blocked requests
2581 */
2582int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2583{
Al Viro72c2d532013-09-22 16:27:52 -04002584 if (filp->f_op->lock)
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002585 return filp->f_op->lock(filp, F_CANCELLK, fl);
2586 return 0;
2587}
2588
2589EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2590
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002591#ifdef CONFIG_PROC_FS
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002592#include <linux/proc_fs.h>
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002593#include <linux/seq_file.h>
2594
Jeff Layton7012b022013-06-21 08:58:22 -04002595struct locks_iterator {
2596 int li_cpu;
2597 loff_t li_pos;
2598};
2599
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002600static void lock_get_status(struct seq_file *f, struct file_lock *fl,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002601 loff_t id, char *pfx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002602{
2603 struct inode *inode = NULL;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002604 unsigned int fl_pid;
2605
2606 if (fl->fl_nspid)
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08002607 fl_pid = pid_vnr(fl->fl_nspid);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002608 else
2609 fl_pid = fl->fl_pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002610
2611 if (fl->fl_file != NULL)
Al Viro496ad9a2013-01-23 17:07:38 -05002612 inode = file_inode(fl->fl_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002613
Jerome Marchand99dc8292010-10-26 14:22:33 -07002614 seq_printf(f, "%lld:%s ", id, pfx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002615 if (IS_POSIX(fl)) {
Jeff Laytonc918d422014-02-03 12:13:09 -05002616 if (fl->fl_flags & FL_ACCESS)
Fabian Frederick5315c262014-05-09 14:13:05 -04002617 seq_puts(f, "ACCESS");
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002618 else if (IS_OFDLCK(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002619 seq_puts(f, "OFDLCK");
Jeff Laytonc918d422014-02-03 12:13:09 -05002620 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002621 seq_puts(f, "POSIX ");
Jeff Laytonc918d422014-02-03 12:13:09 -05002622
2623 seq_printf(f, " %s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002624 (inode == NULL) ? "*NOINODE*" :
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002625 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002626 } else if (IS_FLOCK(fl)) {
2627 if (fl->fl_type & LOCK_MAND) {
Fabian Frederick5315c262014-05-09 14:13:05 -04002628 seq_puts(f, "FLOCK MSNFS ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002629 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002630 seq_puts(f, "FLOCK ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631 }
2632 } else if (IS_LEASE(fl)) {
Jeff Layton8144f1f2014-08-11 13:36:54 -04002633 if (fl->fl_flags & FL_DELEG)
2634 seq_puts(f, "DELEG ");
2635 else
2636 seq_puts(f, "LEASE ");
2637
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002638 if (lease_breaking(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002639 seq_puts(f, "BREAKING ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002640 else if (fl->fl_file)
Fabian Frederick5315c262014-05-09 14:13:05 -04002641 seq_puts(f, "ACTIVE ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002642 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002643 seq_puts(f, "BREAKER ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002644 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002645 seq_puts(f, "UNKNOWN UNKNOWN ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646 }
2647 if (fl->fl_type & LOCK_MAND) {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002648 seq_printf(f, "%s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 (fl->fl_type & LOCK_READ)
2650 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2651 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2652 } else {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002653 seq_printf(f, "%s ",
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002654 (lease_breaking(fl))
Jeff Layton0ee5c6d2012-08-02 15:46:30 -04002655 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2656 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002657 }
2658 if (inode) {
Jeff Layton36488882015-04-03 09:04:04 -04002659 /* userspace relies on this representation of dev_t */
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002660 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002661 MAJOR(inode->i_sb->s_dev),
2662 MINOR(inode->i_sb->s_dev), inode->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002663 } else {
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002664 seq_printf(f, "%d <none>:0 ", fl_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002665 }
2666 if (IS_POSIX(fl)) {
2667 if (fl->fl_end == OFFSET_MAX)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002668 seq_printf(f, "%Ld EOF\n", fl->fl_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002669 else
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002670 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002671 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002672 seq_puts(f, "0 EOF\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002673 }
2674}
2675
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002676static int locks_show(struct seq_file *f, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002677{
Jeff Layton7012b022013-06-21 08:58:22 -04002678 struct locks_iterator *iter = f->private;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002679 struct file_lock *fl, *bfl;
2680
Jeff Layton139ca042013-06-21 08:58:17 -04002681 fl = hlist_entry(v, struct file_lock, fl_link);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002682
Jeff Layton7012b022013-06-21 08:58:22 -04002683 lock_get_status(f, fl, iter->li_pos, "");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002684
2685 list_for_each_entry(bfl, &fl->fl_block, fl_block)
Jeff Layton7012b022013-06-21 08:58:22 -04002686 lock_get_status(f, bfl, iter->li_pos, " ->");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002687
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002688 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002689}
2690
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002691static void __show_fd_locks(struct seq_file *f,
2692 struct list_head *head, int *id,
2693 struct file *filp, struct files_struct *files)
2694{
2695 struct file_lock *fl;
2696
2697 list_for_each_entry(fl, head, fl_list) {
2698
2699 if (filp != fl->fl_file)
2700 continue;
2701 if (fl->fl_owner != files &&
2702 fl->fl_owner != filp)
2703 continue;
2704
2705 (*id)++;
2706 seq_puts(f, "lock:\t");
2707 lock_get_status(f, fl, *id, "");
2708 }
2709}
2710
2711void show_fd_locks(struct seq_file *f,
2712 struct file *filp, struct files_struct *files)
2713{
2714 struct inode *inode = file_inode(filp);
2715 struct file_lock_context *ctx;
2716 int id = 0;
2717
Dmitry Vyukov128a3782015-09-21 09:43:06 +02002718 ctx = smp_load_acquire(&inode->i_flctx);
Andrey Vagin6c8c9032015-04-16 12:49:38 -07002719 if (!ctx)
2720 return;
2721
2722 spin_lock(&ctx->flc_lock);
2723 __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
2724 __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
2725 __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
2726 spin_unlock(&ctx->flc_lock);
2727}
2728
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002729static void *locks_start(struct seq_file *f, loff_t *pos)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002730 __acquires(&blocked_lock_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002731{
Jeff Layton7012b022013-06-21 08:58:22 -04002732 struct locks_iterator *iter = f->private;
Jerome Marchand99dc8292010-10-26 14:22:33 -07002733
Jeff Layton7012b022013-06-21 08:58:22 -04002734 iter->li_pos = *pos + 1;
Peter Zijlstraaba37662015-06-22 14:16:33 +02002735 percpu_down_write(&file_rwsem);
Jeff Layton7b2296a2013-06-21 08:58:20 -04002736 spin_lock(&blocked_lock_lock);
Peter Zijlstra7c3f6542015-06-22 14:16:34 +02002737 return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002738}
2739
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002740static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2741{
Jeff Layton7012b022013-06-21 08:58:22 -04002742 struct locks_iterator *iter = f->private;
2743
2744 ++iter->li_pos;
Peter Zijlstra7c3f6542015-06-22 14:16:34 +02002745 return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002746}
2747
2748static void locks_stop(struct seq_file *f, void *v)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002749 __releases(&blocked_lock_lock)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002750{
Jeff Layton7b2296a2013-06-21 08:58:20 -04002751 spin_unlock(&blocked_lock_lock);
Peter Zijlstraaba37662015-06-22 14:16:33 +02002752 percpu_up_write(&file_rwsem);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002753}
2754
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002755static const struct seq_operations locks_seq_operations = {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002756 .start = locks_start,
2757 .next = locks_next,
2758 .stop = locks_stop,
2759 .show = locks_show,
2760};
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002761
2762static int locks_open(struct inode *inode, struct file *filp)
2763{
Jeff Layton7012b022013-06-21 08:58:22 -04002764 return seq_open_private(filp, &locks_seq_operations,
2765 sizeof(struct locks_iterator));
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002766}
2767
2768static const struct file_operations proc_locks_operations = {
2769 .open = locks_open,
2770 .read = seq_read,
2771 .llseek = seq_lseek,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002772 .release = seq_release_private,
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002773};
2774
2775static int __init proc_locks_init(void)
2776{
2777 proc_create("locks", 0, NULL, &proc_locks_operations);
2778 return 0;
2779}
Paul Gortmaker91899222015-12-17 14:11:03 -05002780fs_initcall(proc_locks_init);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002781#endif
2782
Linus Torvalds1da177e2005-04-16 15:20:36 -07002783static int __init filelock_init(void)
2784{
Jeff Layton7012b022013-06-21 08:58:22 -04002785 int i;
2786
Jeff Layton4a075e32015-01-16 15:05:54 -05002787 flctx_cache = kmem_cache_create("file_lock_ctx",
2788 sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
2789
Linus Torvalds1da177e2005-04-16 15:20:36 -07002790 filelock_cache = kmem_cache_create("file_lock_cache",
Miklos Szerediee19cc42011-07-07 13:06:09 +02002791 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2792
Jeff Layton7012b022013-06-21 08:58:22 -04002793
Peter Zijlstra7c3f6542015-06-22 14:16:34 +02002794 for_each_possible_cpu(i) {
2795 struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
2796
2797 spin_lock_init(&fll->lock);
2798 INIT_HLIST_HEAD(&fll->hlist);
2799 }
Jeff Layton7012b022013-06-21 08:58:22 -04002800
Linus Torvalds1da177e2005-04-16 15:20:36 -07002801 return 0;
2802}
2803
2804core_initcall(filelock_init);