blob: 6e31695d046fefcbeffa3ca9788054f1ce27adb2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/lockd/svclock.c
3 *
4 * Handling of server-side locks, mostly of the blocked variety.
5 * This is the ugliest part of lockd because we tread on very thin ice.
6 * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
7 * IMNSHO introducing the grant callback into the NLM protocol was one
8 * of the worst ideas Sun ever had. Except maybe for the idea of doing
9 * NFS file locking at all.
10 *
11 * I'm trying hard to avoid race conditions by protecting most accesses
12 * to a file's list of blocked locks through a semaphore. The global
13 * list of blocked locks is not protected in this fashion however.
14 * Therefore, some functions (such as the RPC callback for the async grant
15 * call) move blocked locks towards the head of the list *while some other
16 * process might be traversing it*. This should not be a problem in
17 * practice, because this will only cause functions traversing the list
18 * to visit some blocks twice.
19 *
20 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
21 */
22
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/types.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090024#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/errno.h>
26#include <linux/kernel.h>
27#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/sunrpc/clnt.h>
29#include <linux/sunrpc/svc.h>
30#include <linux/lockd/nlm.h>
31#include <linux/lockd/lockd.h>
Jeff Laytond751a7c2008-02-07 16:34:55 -050032#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#define NLMDBG_FACILITY NLMDBG_SVCLOCK
35
36#ifdef CONFIG_LOCKD_V4
37#define nlm_deadlock nlm4_deadlock
38#else
39#define nlm_deadlock nlm_lck_denied
40#endif
41
Trond Myklebust6849c0c2006-03-20 13:44:39 -050042static void nlmsvc_release_block(struct nlm_block *block);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -070044static void nlmsvc_remove_block(struct nlm_block *block);
Trond Myklebust963d8fe2006-01-03 09:55:04 +010045
Trond Myklebust5e1abf82006-03-20 13:44:39 -050046static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
47static void nlmsvc_freegrantargs(struct nlm_rqst *call);
Trond Myklebust963d8fe2006-01-03 09:55:04 +010048static const struct rpc_call_ops nlmsvc_grant_ops;
Chuck Leverd8367c52010-12-14 14:57:52 +000049static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie);
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
51/*
52 * The list of blocked locks to retry
53 */
Olaf Kirch68a2d76c2006-10-04 02:15:57 -070054static LIST_HEAD(nlm_blocked);
Bryan Schumakerf904be92010-09-21 16:38:12 -040055static DEFINE_SPINLOCK(nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57/*
58 * Insert a blocked lock into the global list
59 */
60static void
Bryan Schumakerf904be92010-09-21 16:38:12 -040061nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -070063 struct nlm_block *b;
64 struct list_head *pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -070067 if (list_empty(&block->b_list)) {
68 kref_get(&block->b_count);
69 } else {
70 list_del_init(&block->b_list);
71 }
72
73 pos = &nlm_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 if (when != NLM_NEVER) {
75 if ((when += jiffies) == NLM_NEVER)
76 when ++;
Olaf Kirch68a2d76c2006-10-04 02:15:57 -070077 list_for_each(pos, &nlm_blocked) {
78 b = list_entry(pos, struct nlm_block, b_list);
79 if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
80 break;
81 }
82 /* On normal exit from the loop, pos == &nlm_blocked,
83 * so we will be adding to the end of the list - good
84 */
85 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Olaf Kirch68a2d76c2006-10-04 02:15:57 -070087 list_add_tail(&block->b_list, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 block->b_when = when;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089}
90
Bryan Schumakerf904be92010-09-21 16:38:12 -040091static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
92{
93 spin_lock(&nlm_blocked_lock);
94 nlmsvc_insert_block_locked(block, when);
95 spin_unlock(&nlm_blocked_lock);
96}
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098/*
99 * Remove a block from the global list
100 */
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700101static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102nlmsvc_remove_block(struct nlm_block *block)
103{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700104 if (!list_empty(&block->b_list)) {
Bryan Schumakerf904be92010-09-21 16:38:12 -0400105 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700106 list_del_init(&block->b_list);
Bryan Schumakerf904be92010-09-21 16:38:12 -0400107 spin_unlock(&nlm_blocked_lock);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700108 nlmsvc_release_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110}
111
112/*
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500113 * Find a block for a given lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 */
115static struct nlm_block *
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500116nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700118 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 struct file_lock *fl;
120
121 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
122 file, lock->fl.fl_pid,
123 (long long)lock->fl.fl_start,
124 (long long)lock->fl.fl_end, lock->fl.fl_type);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700125 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust92737232006-03-20 13:44:45 -0500126 fl = &block->b_call->a_args.lock.fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
128 block->b_file, fl->fl_pid,
129 (long long)fl->fl_start,
130 (long long)fl->fl_end, fl->fl_type,
Trond Myklebust92737232006-03-20 13:44:45 -0500131 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500133 kref_get(&block->b_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 return block;
135 }
136 }
137
138 return NULL;
139}
140
141static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
142{
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400143 if (a->len != b->len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 return 0;
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400145 if (memcmp(a->data, b->data, a->len))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 return 0;
147 return 1;
148}
149
150/*
151 * Find a block with a given NLM cookie.
152 */
153static inline struct nlm_block *
Olaf Kirch39be4502006-10-04 02:16:03 -0700154nlmsvc_find_block(struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
156 struct nlm_block *block;
157
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700158 list_for_each_entry(block, &nlm_blocked, b_list) {
Olaf Kirch39be4502006-10-04 02:16:03 -0700159 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie))
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700160 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 }
162
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700163 return NULL;
164
165found:
Olaf Kirch39be4502006-10-04 02:16:03 -0700166 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700167 kref_get(&block->b_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 return block;
169}
170
171/*
172 * Create a block and initialize it.
173 *
174 * Note: we explicitly set the cookie of the grant reply to that of
175 * the blocked lock request. The spec explicitly mentions that the client
176 * should _not_ rely on the callback containing the same cookie as the
177 * request, but (as I found out later) that's because some implementations
178 * do just this. Never mind the standards comittees, they support our
179 * logging industries.
Olaf Kirch39be4502006-10-04 02:16:03 -0700180 *
181 * 10 years later: I hope we can safely ignore these old and broken
182 * clients by now. Let's fix this so we can uniquely identify an incoming
183 * GRANTED_RES message by cookie, without having to rely on the client's IP
184 * address. --okir
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 */
Trond Myklebust255129d2007-09-25 15:55:03 -0400186static struct nlm_block *
187nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
188 struct nlm_file *file, struct nlm_lock *lock,
189 struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190{
191 struct nlm_block *block;
Trond Myklebust92737232006-03-20 13:44:45 -0500192 struct nlm_rqst *call = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
J. Bruce Fields560de0e2008-07-15 15:05:45 -0400194 nlm_get_host(host);
Trond Myklebust92737232006-03-20 13:44:45 -0500195 call = nlm_alloc_call(host);
196 if (call == NULL)
197 return NULL;
198
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 /* Allocate memory for block, and initialize arguments */
Trond Myklebust92737232006-03-20 13:44:45 -0500200 block = kzalloc(sizeof(*block), GFP_KERNEL);
201 if (block == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 goto failed;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500203 kref_init(&block->b_count);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700204 INIT_LIST_HEAD(&block->b_list);
205 INIT_LIST_HEAD(&block->b_flist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Trond Myklebust92737232006-03-20 13:44:45 -0500207 if (!nlmsvc_setgrantargs(call, lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 goto failed_free;
209
210 /* Set notifier function for VFS, and init args */
Trond Myklebust92737232006-03-20 13:44:45 -0500211 call->a_args.lock.fl.fl_flags |= FL_SLEEP;
212 call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
Olaf Kirch39be4502006-10-04 02:16:03 -0700213 nlmclnt_next_cookie(&call->a_args.cookie);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
215 dprintk("lockd: created block %p...\n", block);
216
217 /* Create and initialize the block */
218 block->b_daemon = rqstp->rq_server;
219 block->b_host = host;
220 block->b_file = file;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500221 block->b_fl = NULL;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500222 file->f_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
224 /* Add to file's list of blocks */
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700225 list_add(&block->b_flist, &file->f_blocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227 /* Set up RPC arguments for callback */
Trond Myklebust92737232006-03-20 13:44:45 -0500228 block->b_call = call;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 call->a_flags = RPC_TASK_ASYNC;
Trond Myklebust92737232006-03-20 13:44:45 -0500230 call->a_block = block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
232 return block;
233
234failed_free:
235 kfree(block);
236failed:
Chuck Lever7db836d2010-12-14 15:05:42 +0000237 nlmsvc_release_call(call);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 return NULL;
239}
240
241/*
J. Bruce Fields3c61eec2008-04-07 13:05:27 -0400242 * Delete a block.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 * It is the caller's responsibility to check whether the file
244 * can be closed hereafter.
245 */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500246static int nlmsvc_unlink_block(struct nlm_block *block)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247{
Trond Myklebust09c79382006-03-20 13:44:38 -0500248 int status;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500249 dprintk("lockd: unlinking block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250
251 /* Remove block from list */
Trond Myklebust92737232006-03-20 13:44:45 -0500252 status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 nlmsvc_remove_block(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500254 return status;
255}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500257static void nlmsvc_free_block(struct kref *kref)
258{
259 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
260 struct nlm_file *file = block->b_file;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500261
262 dprintk("lockd: freeing block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
264 /* Remove block from file's list of blocks */
Neil Brown89e63ef2006-10-04 02:16:06 -0700265 mutex_lock(&file->f_mutex);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700266 list_del_init(&block->b_flist);
Neil Brown89e63ef2006-10-04 02:16:06 -0700267 mutex_unlock(&file->f_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Trond Myklebust92737232006-03-20 13:44:45 -0500269 nlmsvc_freegrantargs(block->b_call);
Chuck Lever7db836d2010-12-14 15:05:42 +0000270 nlmsvc_release_call(block->b_call);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500271 nlm_release_file(block->b_file);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500272 kfree(block->b_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 kfree(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500274}
275
276static void nlmsvc_release_block(struct nlm_block *block)
277{
278 if (block != NULL)
279 kref_put(&block->b_count, nlmsvc_free_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280}
281
Olaf Kirchf2af7932006-10-04 02:15:59 -0700282/*
283 * Loop over all blocks and delete blocks held by
284 * a matching host.
285 */
286void nlmsvc_traverse_blocks(struct nlm_host *host,
287 struct nlm_file *file,
288 nlm_host_match_fn_t match)
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500289{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700290 struct nlm_block *block, *next;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500291
292restart:
Neil Brown89e63ef2006-10-04 02:16:06 -0700293 mutex_lock(&file->f_mutex);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700294 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
Olaf Kirchf2af7932006-10-04 02:15:59 -0700295 if (!match(block->b_host, host))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500296 continue;
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700297 /* Do not destroy blocks that are not on
298 * the global retry list - why? */
299 if (list_empty(&block->b_list))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500300 continue;
301 kref_get(&block->b_count);
Neil Brown89e63ef2006-10-04 02:16:06 -0700302 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500303 nlmsvc_unlink_block(block);
304 nlmsvc_release_block(block);
305 goto restart;
306 }
Neil Brown89e63ef2006-10-04 02:16:06 -0700307 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500308}
309
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310/*
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500311 * Initialize arguments for GRANTED call. The nlm_rqst structure
312 * has been cleared already.
313 */
314static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
315{
316 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
317 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
Serge E. Hallyne9ff3992006-10-02 02:18:11 -0700318 call->a_args.lock.caller = utsname()->nodename;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500319 call->a_args.lock.oh.len = lock->oh.len;
320
321 /* set default data area */
322 call->a_args.lock.oh.data = call->a_owner;
323 call->a_args.lock.svid = lock->fl.fl_pid;
324
325 if (lock->oh.len > NLMCLNT_OHSIZE) {
326 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
Trond Myklebust92737232006-03-20 13:44:45 -0500327 if (!data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500328 return 0;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500329 call->a_args.lock.oh.data = (u8 *) data;
330 }
331
332 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
333 return 1;
334}
335
336static void nlmsvc_freegrantargs(struct nlm_rqst *call)
337{
Trond Myklebust92737232006-03-20 13:44:45 -0500338 if (call->a_args.lock.oh.data != call->a_owner)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500339 kfree(call->a_args.lock.oh.data);
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500340
341 locks_release_private(&call->a_args.lock.fl);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500342}
343
344/*
Marc Eshel2b36f412006-11-28 16:26:47 -0500345 * Deferred lock request handling for non-blocking lock
346 */
Al Viroca5c8cd2007-07-26 17:33:49 +0100347static __be32
Marc Eshel2b36f412006-11-28 16:26:47 -0500348nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
349{
Al Viroca5c8cd2007-07-26 17:33:49 +0100350 __be32 status = nlm_lck_denied_nolocks;
Marc Eshel2b36f412006-11-28 16:26:47 -0500351
352 block->b_flags |= B_QUEUED;
353
354 nlmsvc_insert_block(block, NLM_TIMEOUT);
355
356 block->b_cache_req = &rqstp->rq_chandle;
357 if (rqstp->rq_chandle.defer) {
358 block->b_deferred_req =
359 rqstp->rq_chandle.defer(block->b_cache_req);
360 if (block->b_deferred_req != NULL)
361 status = nlm_drop_reply;
362 }
363 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
Al Viroca5c8cd2007-07-26 17:33:49 +0100364 block, block->b_flags, ntohl(status));
Marc Eshel2b36f412006-11-28 16:26:47 -0500365
366 return status;
367}
368
369/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 * Attempt to establish a lock, and if it can't be granted, block it
371 * if required.
372 */
Al Viro52921e02006-10-19 23:28:46 -0700373__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton6cde4de2008-07-15 14:26:17 -0400375 struct nlm_host *host, struct nlm_lock *lock, int wait,
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500376 struct nlm_cookie *cookie, int reclaim)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377{
Marc Eshelf8120482006-12-05 23:48:10 -0500378 struct nlm_block *block = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 int error;
Al Viro52921e02006-10-19 23:28:46 -0700380 __be32 ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
382 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800383 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
384 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 lock->fl.fl_type, lock->fl.fl_pid,
386 (long long)lock->fl.fl_start,
387 (long long)lock->fl.fl_end,
388 wait);
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 /* Lock file against concurrent access */
Neil Brown89e63ef2006-10-04 02:16:06 -0700391 mutex_lock(&file->f_mutex);
Marc Eshelf8120482006-12-05 23:48:10 -0500392 /* Get existing block (in case client is busy-waiting)
393 * or create new block
394 */
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500395 block = nlmsvc_lookup_block(file, lock);
Trond Myklebust09c79382006-03-20 13:44:38 -0500396 if (block == NULL) {
J. Bruce Fields560de0e2008-07-15 15:05:45 -0400397 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshelf8120482006-12-05 23:48:10 -0500398 ret = nlm_lck_denied_nolocks;
399 if (block == NULL)
400 goto out;
Trond Myklebust92737232006-03-20 13:44:45 -0500401 lock = &block->b_call->a_args.lock;
Marc Eshelf8120482006-12-05 23:48:10 -0500402 } else
403 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404
Marc Eshel1a8322b2006-11-28 16:27:06 -0500405 if (block->b_flags & B_QUEUED) {
406 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
407 block, block->b_flags);
408 if (block->b_granted) {
409 nlmsvc_unlink_block(block);
410 ret = nlm_granted;
411 goto out;
412 }
413 if (block->b_flags & B_TIMED_OUT) {
414 nlmsvc_unlink_block(block);
415 ret = nlm_lck_denied;
416 goto out;
417 }
418 ret = nlm_drop_reply;
419 goto out;
420 }
421
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500422 if (locks_in_grace() && !reclaim) {
423 ret = nlm_lck_denied_grace_period;
424 goto out;
425 }
J. Bruce Fieldsd22b1cf2008-02-06 15:05:12 -0500426 if (reclaim && !locks_in_grace()) {
427 ret = nlm_lck_denied_grace_period;
428 goto out;
429 }
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500430
Marc Eshel1a8322b2006-11-28 16:27:06 -0500431 if (!wait)
432 lock->fl.fl_flags &= ~FL_SLEEP;
433 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500434 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
Marc Eshel1a8322b2006-11-28 16:27:06 -0500436 dprintk("lockd: vfs_lock_file returned %d\n", error);
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400437 switch (error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 case 0:
Andy Adamson15dadef2006-03-20 13:44:24 -0500439 ret = nlm_granted;
440 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500441 case -EAGAIN:
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500442 /*
443 * If this is a blocking request for an
444 * already pending lock request then we need
445 * to put it back on lockd's block list
446 */
447 if (wait)
448 break;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500449 ret = nlm_lck_denied;
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500450 goto out;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700451 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500452 if (wait)
453 break;
454 /* Filesystem lock operation is in progress
455 Add it to the queue waiting for callback */
456 ret = nlmsvc_defer_lock_rqst(rqstp, block);
457 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500458 case -EDEADLK:
Andy Adamson15dadef2006-03-20 13:44:24 -0500459 ret = nlm_deadlock;
460 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 default: /* includes ENOLCK */
Andy Adamson15dadef2006-03-20 13:44:24 -0500462 ret = nlm_lck_denied_nolocks;
463 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 }
465
Trond Myklebust09c79382006-03-20 13:44:38 -0500466 ret = nlm_lck_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
468 /* Append to list of blocked */
Marc Eshelf8120482006-12-05 23:48:10 -0500469 nlmsvc_insert_block(block, NLM_NEVER);
Andy Adamson15dadef2006-03-20 13:44:24 -0500470out:
Neil Brown89e63ef2006-10-04 02:16:06 -0700471 mutex_unlock(&file->f_mutex);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500472 nlmsvc_release_block(block);
Andy Adamson15dadef2006-03-20 13:44:24 -0500473 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
474 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475}
476
477/*
478 * Test for presence of a conflicting lock.
479 */
Al Viro52921e02006-10-19 23:28:46 -0700480__be32
Marc Eshel85f3f1b32006-11-28 16:27:06 -0500481nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton8f920d52008-07-15 14:06:48 -0400482 struct nlm_host *host, struct nlm_lock *lock,
483 struct nlm_lock *conflock, struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484{
Marc Eshel5ea0d752006-11-28 16:27:06 -0500485 struct nlm_block *block = NULL;
486 int error;
487 __be32 ret;
488
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800490 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
491 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 lock->fl.fl_type,
493 (long long)lock->fl.fl_start,
494 (long long)lock->fl.fl_end);
495
Marc Eshel5ea0d752006-11-28 16:27:06 -0500496 /* Get existing block (in case client is busy-waiting) */
497 block = nlmsvc_lookup_block(file, lock);
498
499 if (block == NULL) {
500 struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
501
502 if (conf == NULL)
503 return nlm_granted;
Trond Myklebust255129d2007-09-25 15:55:03 -0400504 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500505 if (block == NULL) {
506 kfree(conf);
507 return nlm_granted;
508 }
509 block->b_fl = conf;
510 }
511 if (block->b_flags & B_QUEUED) {
512 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
513 block, block->b_flags, block->b_fl);
514 if (block->b_flags & B_TIMED_OUT) {
515 nlmsvc_unlink_block(block);
Oleg Drokin29dbf542007-11-29 14:02:21 -0500516 ret = nlm_lck_denied;
517 goto out;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500518 }
519 if (block->b_flags & B_GOT_CALLBACK) {
Oleg Drokin54ca95e2008-01-11 21:57:35 -0500520 nlmsvc_unlink_block(block);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500521 if (block->b_fl != NULL
522 && block->b_fl->fl_type != F_UNLCK) {
523 lock->fl = *block->b_fl;
524 goto conf_lock;
Oleg Drokin29dbf542007-11-29 14:02:21 -0500525 } else {
Oleg Drokin29dbf542007-11-29 14:02:21 -0500526 ret = nlm_granted;
527 goto out;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500528 }
529 }
Oleg Drokin29dbf542007-11-29 14:02:21 -0500530 ret = nlm_drop_reply;
531 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 }
533
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500534 if (locks_in_grace()) {
535 ret = nlm_lck_denied_grace_period;
536 goto out;
537 }
Marc Eshel5ea0d752006-11-28 16:27:06 -0500538 error = vfs_test_lock(file->f_file, &lock->fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -0700539 if (error == FILE_LOCK_DEFERRED) {
Oleg Drokin29dbf542007-11-29 14:02:21 -0500540 ret = nlmsvc_defer_lock_rqst(rqstp, block);
541 goto out;
542 }
Marc Eshel5ea0d752006-11-28 16:27:06 -0500543 if (error) {
544 ret = nlm_lck_denied_nolocks;
545 goto out;
546 }
547 if (lock->fl.fl_type == F_UNLCK) {
548 ret = nlm_granted;
549 goto out;
550 }
551
552conf_lock:
553 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
554 lock->fl.fl_type, (long long)lock->fl.fl_start,
555 (long long)lock->fl.fl_end);
556 conflock->caller = "somehost"; /* FIXME */
557 conflock->len = strlen(conflock->caller);
558 conflock->oh.len = 0; /* don't return OH info */
559 conflock->svid = lock->fl.fl_pid;
560 conflock->fl.fl_type = lock->fl.fl_type;
561 conflock->fl.fl_start = lock->fl.fl_start;
562 conflock->fl.fl_end = lock->fl.fl_end;
563 ret = nlm_lck_denied;
564out:
565 if (block)
566 nlmsvc_release_block(block);
567 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568}
569
570/*
571 * Remove a lock.
572 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
573 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
574 * afterwards. In this case the block will still be there, and hence
575 * must be removed.
576 */
Al Viro52921e02006-10-19 23:28:46 -0700577__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
579{
580 int error;
581
582 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800583 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
584 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 lock->fl.fl_pid,
586 (long long)lock->fl.fl_start,
587 (long long)lock->fl.fl_end);
588
589 /* First, cancel any lock that might be there */
590 nlmsvc_cancel_blocked(file, lock);
591
592 lock->fl.fl_type = F_UNLCK;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500593 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
595 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
596}
597
598/*
599 * Cancel a previously blocked request.
600 *
601 * A cancel request always overrides any grant that may currently
602 * be in progress.
603 * The calling procedure must check whether the file can be closed.
604 */
Al Viro52921e02006-10-19 23:28:46 -0700605__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
607{
608 struct nlm_block *block;
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100609 int status = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
611 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800612 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
613 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 lock->fl.fl_pid,
615 (long long)lock->fl.fl_start,
616 (long long)lock->fl.fl_end);
617
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500618 if (locks_in_grace())
619 return nlm_lck_denied_grace_period;
620
Neil Brown89e63ef2006-10-04 02:16:06 -0700621 mutex_lock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500622 block = nlmsvc_lookup_block(file, lock);
Neil Brown89e63ef2006-10-04 02:16:06 -0700623 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500624 if (block != NULL) {
Marc Eshel1a8322b2006-11-28 16:27:06 -0500625 vfs_cancel_lock(block->b_file->f_file,
626 &block->b_call->a_args.lock.fl);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500627 status = nlmsvc_unlink_block(block);
628 nlmsvc_release_block(block);
629 }
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100630 return status ? nlm_lck_denied : nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631}
632
633/*
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500634 * This is a callback from the filesystem for VFS file lock requests.
635 * It will be used if fl_grant is defined and the filesystem can not
636 * respond to the request immediately.
637 * For GETLK request it will copy the reply to the nlm_block.
638 * For SETLK or SETLKW request it will get the local posix lock.
639 * In all cases it will move the block to the head of nlm_blocked q where
640 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
641 * deferred rpc for GETLK and SETLK.
642 */
643static void
644nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf,
645 int result)
646{
647 block->b_flags |= B_GOT_CALLBACK;
648 if (result == 0)
649 block->b_granted = 1;
650 else
651 block->b_flags |= B_TIMED_OUT;
652 if (conf) {
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500653 if (block->b_fl)
J. Bruce Fields1a747ee2008-04-24 10:08:22 -0400654 __locks_copy_lock(block->b_fl, conf);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500655 }
656}
657
658static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
659 int result)
660{
661 struct nlm_block *block;
662 int rc = -ENOENT;
663
Bryan Schumakerf904be92010-09-21 16:38:12 -0400664 spin_lock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500665 list_for_each_entry(block, &nlm_blocked, b_list) {
666 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
667 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
668 block, block->b_flags);
669 if (block->b_flags & B_QUEUED) {
670 if (block->b_flags & B_TIMED_OUT) {
671 rc = -ENOLCK;
672 break;
673 }
674 nlmsvc_update_deferred_block(block, conf, result);
675 } else if (result == 0)
676 block->b_granted = 1;
677
Bryan Schumakerf904be92010-09-21 16:38:12 -0400678 nlmsvc_insert_block_locked(block, 0);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500679 svc_wake_up(block->b_daemon);
680 rc = 0;
681 break;
682 }
683 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400684 spin_unlock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500685 if (rc == -ENOENT)
686 printk(KERN_WARNING "lockd: grant for unknown block\n");
687 return rc;
688}
689
690/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 * Unblock a blocked lock request. This is a callback invoked from the
692 * VFS layer when a lock on which we blocked is removed.
693 *
694 * This function doesn't grant the blocked lock instantly, but rather moves
695 * the block to the head of nlm_blocked where it can be picked up by lockd.
696 */
697static void
698nlmsvc_notify_blocked(struct file_lock *fl)
699{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700700 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
702 dprintk("lockd: VFS unblock notification for block %p\n", fl);
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400703 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700704 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust92737232006-03-20 13:44:45 -0500705 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400706 nlmsvc_insert_block_locked(block, 0);
707 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 svc_wake_up(block->b_daemon);
709 return;
710 }
711 }
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400712 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 printk(KERN_WARNING "lockd: notification for unknown block!\n");
714}
715
716static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
717{
718 return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
719}
720
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700721const struct lock_manager_operations nlmsvc_lock_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 .fl_compare_owner = nlmsvc_same_owner,
723 .fl_notify = nlmsvc_notify_blocked,
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500724 .fl_grant = nlmsvc_grant_deferred,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725};
726
727/*
728 * Try to claim a lock that was previously blocked.
729 *
730 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
731 * RPC thread when notifying the client. This seems like overkill...
732 * Here's why:
733 * - we don't want to use a synchronous RPC thread, otherwise
734 * we might find ourselves hanging on a dead portmapper.
735 * - Some lockd implementations (e.g. HP) don't react to
736 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
737 */
738static void
739nlmsvc_grant_blocked(struct nlm_block *block)
740{
741 struct nlm_file *file = block->b_file;
Trond Myklebust92737232006-03-20 13:44:45 -0500742 struct nlm_lock *lock = &block->b_call->a_args.lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 int error;
744
745 dprintk("lockd: grant blocked lock %p\n", block);
746
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500747 kref_get(&block->b_count);
748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 /* Unlink block request from list */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500750 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751
752 /* If b_granted is true this means we've been here before.
753 * Just retry the grant callback, possibly refreshing the RPC
754 * binding */
755 if (block->b_granted) {
756 nlm_rebind_host(block->b_host);
757 goto callback;
758 }
759
760 /* Try the lock operation again */
Trond Myklebust09c79382006-03-20 13:44:38 -0500761 lock->fl.fl_flags |= FL_SLEEP;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500762 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500763 lock->fl.fl_flags &= ~FL_SLEEP;
764
Andy Adamson5de0e502006-03-20 13:44:25 -0500765 switch (error) {
766 case 0:
767 break;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700768 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500769 dprintk("lockd: lock still blocked error %d\n", error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 nlmsvc_insert_block(block, NLM_NEVER);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500771 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500772 return;
Andy Adamson5de0e502006-03-20 13:44:25 -0500773 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700775 -error, __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 nlmsvc_insert_block(block, 10 * HZ);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500777 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500778 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 }
780
781callback:
782 /* Lock was granted by VFS. */
783 dprintk("lockd: GRANTing blocked lock.\n");
784 block->b_granted = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785
Jeff Layton97065012008-02-06 11:34:12 -0500786 /* keep block on the list, but don't reattempt until the RPC
787 * completes or the submission fails
788 */
789 nlmsvc_insert_block(block, NLM_NEVER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790
Jeff Layton97065012008-02-06 11:34:12 -0500791 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
792 * will queue up a new one if this one times out
793 */
794 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
795 &nlmsvc_grant_ops);
796
797 /* RPC submission failed, wait a bit and retry */
798 if (error < 0)
799 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800}
801
802/*
803 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
804 * RPC call has succeeded or timed out.
805 * Like all RPC callbacks, it is invoked by the rpciod process, so it
806 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
807 * chain once more in order to have it removed by lockd itself (which can
808 * then sleep on the file semaphore without disrupting e.g. the nfs client).
809 */
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100810static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811{
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100812 struct nlm_rqst *call = data;
Trond Myklebust92737232006-03-20 13:44:45 -0500813 struct nlm_block *block = call->a_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 unsigned long timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815
816 dprintk("lockd: GRANT_MSG RPC callback\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817
Bryan Schumakerf904be92010-09-21 16:38:12 -0400818 spin_lock(&nlm_blocked_lock);
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500819 /* if the block is not on a list at this point then it has
820 * been invalidated. Don't try to requeue it.
821 *
822 * FIXME: it's possible that the block is removed from the list
823 * after this check but before the nlmsvc_insert_block. In that
824 * case it will be added back. Perhaps we need better locking
825 * for nlm_blocked?
826 */
827 if (list_empty(&block->b_list))
Trond Myklebusta86dc492008-06-11 13:37:09 -0400828 goto out;
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500829
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 /* Technically, we should down the file semaphore here. Since we
831 * move the block towards the head of the queue only, no harm
832 * can be done, though. */
833 if (task->tk_status < 0) {
834 /* RPC error: Re-insert for retransmission */
835 timeout = 10 * HZ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 } else {
837 /* Call was successful, now wait for client callback */
838 timeout = 60 * HZ;
839 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400840 nlmsvc_insert_block_locked(block, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 svc_wake_up(block->b_daemon);
Trond Myklebusta86dc492008-06-11 13:37:09 -0400842out:
Bryan Schumakerf904be92010-09-21 16:38:12 -0400843 spin_unlock(&nlm_blocked_lock);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500844}
845
Bryan Schumakerf904be92010-09-21 16:38:12 -0400846/*
847 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
848 * .rpc_release rpc_call_op
849 */
Adrian Bunkec535ce152006-04-18 13:21:50 -0400850static void nlmsvc_grant_release(void *data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500851{
Trond Myklebust6041b792006-03-20 13:44:45 -0500852 struct nlm_rqst *call = data;
Trond Myklebust6041b792006-03-20 13:44:45 -0500853 nlmsvc_release_block(call->a_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854}
855
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100856static const struct rpc_call_ops nlmsvc_grant_ops = {
857 .rpc_call_done = nlmsvc_grant_callback,
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500858 .rpc_release = nlmsvc_grant_release,
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100859};
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861/*
862 * We received a GRANT_RES callback. Try to find the corresponding
863 * block.
864 */
865void
Al Viroe8c5c042006-12-13 00:35:03 -0800866nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867{
868 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869
Olaf Kirch39be4502006-10-04 02:16:03 -0700870 dprintk("grant_reply: looking for cookie %x, s=%d \n",
871 *(unsigned int *)(cookie->data), status);
872 if (!(block = nlmsvc_find_block(cookie)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874
J. Bruce Fieldsf2321422006-01-03 09:55:42 +0100875 if (block) {
Al Viroe8c5c042006-12-13 00:35:03 -0800876 if (status == nlm_lck_denied_grace_period) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 /* Try again in a couple of seconds */
878 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 } else {
880 /* Lock is now held by client, or has been rejected.
881 * In both cases, the block should be removed. */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500882 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 }
884 }
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500885 nlmsvc_release_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886}
887
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500888/* Helper function to handle retry of a deferred block.
889 * If it is a blocking lock, call grant_blocked.
890 * For a non-blocking lock or test lock, revisit the request.
891 */
892static void
893retry_deferred_block(struct nlm_block *block)
894{
895 if (!(block->b_flags & B_GOT_CALLBACK))
896 block->b_flags |= B_TIMED_OUT;
897 nlmsvc_insert_block(block, NLM_TIMEOUT);
898 dprintk("revisit block %p flags %d\n", block, block->b_flags);
899 if (block->b_deferred_req) {
900 block->b_deferred_req->revisit(block->b_deferred_req, 0);
901 block->b_deferred_req = NULL;
902 }
903}
904
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905/*
906 * Retry all blocked locks that have been notified. This is where lockd
907 * picks up locks that can be granted, or grant notifications that must
908 * be retransmitted.
909 */
910unsigned long
911nlmsvc_retry_blocked(void)
912{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700913 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
914 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915
Jeff Laytond751a7c2008-02-07 16:34:55 -0500916 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700917 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
918
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 if (block->b_when == NLM_NEVER)
920 break;
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400921 if (time_after(block->b_when, jiffies)) {
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700922 timeout = block->b_when - jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 break;
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700924 }
925
J. Bruce Fieldsf3d43c72006-08-03 15:07:47 -0400926 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
927 block, block->b_when);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500928 if (block->b_flags & B_QUEUED) {
929 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
930 block, block->b_granted, block->b_flags);
931 retry_deferred_block(block);
932 } else
933 nlmsvc_grant_blocked(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 }
935
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700936 return timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937}
Chuck Leverd8367c52010-12-14 14:57:52 +0000938
939#ifdef RPC_DEBUG
940static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
941{
942 /*
943 * We can get away with a static buffer because we're only
944 * called with BKL held.
945 */
946 static char buf[2*NLM_MAXCOOKIELEN+1];
947 unsigned int i, len = sizeof(buf);
948 char *p = buf;
949
950 len--; /* allow for trailing \0 */
951 if (len < 3)
952 return "???";
953 for (i = 0 ; i < cookie->len ; i++) {
954 if (len < 2) {
955 strcpy(p-3, "...");
956 break;
957 }
958 sprintf(p, "%02x", cookie->data[i]);
959 p += 2;
960 len -= 2;
961 }
962 *p = '\0';
963
964 return buf;
965}
966#endif