blob: e46353f41a4202ec2138998ab5449b833dc139db [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 Kirch68a2d762006-10-04 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50/*
51 * The list of blocked locks to retry
52 */
Olaf Kirch68a2d762006-10-04 02:15:57 -070053static LIST_HEAD(nlm_blocked);
Bryan Schumakerf904be92010-09-21 16:38:12 -040054static DEFINE_SPINLOCK(nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Trond Myklebustffa94db2012-03-20 09:22:00 -040056#ifdef LOCKD_DEBUG
57static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
58{
59 /*
60 * We can get away with a static buffer because we're only
61 * called with BKL held.
62 */
63 static char buf[2*NLM_MAXCOOKIELEN+1];
64 unsigned int i, len = sizeof(buf);
65 char *p = buf;
66
67 len--; /* allow for trailing \0 */
68 if (len < 3)
69 return "???";
70 for (i = 0 ; i < cookie->len ; i++) {
71 if (len < 2) {
72 strcpy(p-3, "...");
73 break;
74 }
75 sprintf(p, "%02x", cookie->data[i]);
76 p += 2;
77 len -= 2;
78 }
79 *p = '\0';
80
81 return buf;
82}
83#endif
84
Linus Torvalds1da177e2005-04-16 15:20:36 -070085/*
86 * Insert a blocked lock into the global list
87 */
88static void
Bryan Schumakerf904be92010-09-21 16:38:12 -040089nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090{
Olaf Kirch68a2d762006-10-04 02:15:57 -070091 struct nlm_block *b;
92 struct list_head *pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
94 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
Olaf Kirch68a2d762006-10-04 02:15:57 -070095 if (list_empty(&block->b_list)) {
96 kref_get(&block->b_count);
97 } else {
98 list_del_init(&block->b_list);
99 }
100
101 pos = &nlm_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 if (when != NLM_NEVER) {
103 if ((when += jiffies) == NLM_NEVER)
104 when ++;
Olaf Kirch68a2d762006-10-04 02:15:57 -0700105 list_for_each(pos, &nlm_blocked) {
106 b = list_entry(pos, struct nlm_block, b_list);
107 if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
108 break;
109 }
110 /* On normal exit from the loop, pos == &nlm_blocked,
111 * so we will be adding to the end of the list - good
112 */
113 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
Olaf Kirch68a2d762006-10-04 02:15:57 -0700115 list_add_tail(&block->b_list, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 block->b_when = when;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117}
118
Bryan Schumakerf904be92010-09-21 16:38:12 -0400119static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
120{
121 spin_lock(&nlm_blocked_lock);
122 nlmsvc_insert_block_locked(block, when);
123 spin_unlock(&nlm_blocked_lock);
124}
125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126/*
127 * Remove a block from the global list
128 */
Olaf Kirch68a2d762006-10-04 02:15:57 -0700129static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130nlmsvc_remove_block(struct nlm_block *block)
131{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700132 if (!list_empty(&block->b_list)) {
Bryan Schumakerf904be92010-09-21 16:38:12 -0400133 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700134 list_del_init(&block->b_list);
Bryan Schumakerf904be92010-09-21 16:38:12 -0400135 spin_unlock(&nlm_blocked_lock);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700136 nlmsvc_release_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138}
139
140/*
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500141 * Find a block for a given lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 */
143static struct nlm_block *
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500144nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700146 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 struct file_lock *fl;
148
149 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
150 file, lock->fl.fl_pid,
151 (long long)lock->fl.fl_start,
152 (long long)lock->fl.fl_end, lock->fl.fl_type);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700153 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust92737232006-03-20 13:44:45 -0500154 fl = &block->b_call->a_args.lock.fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
156 block->b_file, fl->fl_pid,
157 (long long)fl->fl_start,
158 (long long)fl->fl_end, fl->fl_type,
Trond Myklebust92737232006-03-20 13:44:45 -0500159 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500161 kref_get(&block->b_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 return block;
163 }
164 }
165
166 return NULL;
167}
168
169static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
170{
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400171 if (a->len != b->len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 return 0;
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400173 if (memcmp(a->data, b->data, a->len))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 return 0;
175 return 1;
176}
177
178/*
179 * Find a block with a given NLM cookie.
180 */
181static inline struct nlm_block *
Olaf Kirch39be4502006-10-04 02:16:03 -0700182nlmsvc_find_block(struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183{
184 struct nlm_block *block;
185
Olaf Kirch68a2d762006-10-04 02:15:57 -0700186 list_for_each_entry(block, &nlm_blocked, b_list) {
Olaf Kirch39be4502006-10-04 02:16:03 -0700187 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie))
Olaf Kirch68a2d762006-10-04 02:15:57 -0700188 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 }
190
Olaf Kirch68a2d762006-10-04 02:15:57 -0700191 return NULL;
192
193found:
Olaf Kirch39be4502006-10-04 02:16:03 -0700194 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700195 kref_get(&block->b_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 return block;
197}
198
199/*
200 * Create a block and initialize it.
201 *
202 * Note: we explicitly set the cookie of the grant reply to that of
203 * the blocked lock request. The spec explicitly mentions that the client
204 * should _not_ rely on the callback containing the same cookie as the
205 * request, but (as I found out later) that's because some implementations
206 * do just this. Never mind the standards comittees, they support our
207 * logging industries.
Olaf Kirch39be4502006-10-04 02:16:03 -0700208 *
209 * 10 years later: I hope we can safely ignore these old and broken
210 * clients by now. Let's fix this so we can uniquely identify an incoming
211 * GRANTED_RES message by cookie, without having to rely on the client's IP
212 * address. --okir
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 */
Trond Myklebust255129d2007-09-25 15:55:03 -0400214static struct nlm_block *
215nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
216 struct nlm_file *file, struct nlm_lock *lock,
217 struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
219 struct nlm_block *block;
Trond Myklebust92737232006-03-20 13:44:45 -0500220 struct nlm_rqst *call = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
J. Bruce Fields560de0e2008-07-15 15:05:45 -0400222 nlm_get_host(host);
Trond Myklebust92737232006-03-20 13:44:45 -0500223 call = nlm_alloc_call(host);
224 if (call == NULL)
225 return NULL;
226
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 /* Allocate memory for block, and initialize arguments */
Trond Myklebust92737232006-03-20 13:44:45 -0500228 block = kzalloc(sizeof(*block), GFP_KERNEL);
229 if (block == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 goto failed;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500231 kref_init(&block->b_count);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700232 INIT_LIST_HEAD(&block->b_list);
233 INIT_LIST_HEAD(&block->b_flist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
Trond Myklebust92737232006-03-20 13:44:45 -0500235 if (!nlmsvc_setgrantargs(call, lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 goto failed_free;
237
238 /* Set notifier function for VFS, and init args */
Trond Myklebust92737232006-03-20 13:44:45 -0500239 call->a_args.lock.fl.fl_flags |= FL_SLEEP;
240 call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
Olaf Kirch39be4502006-10-04 02:16:03 -0700241 nlmclnt_next_cookie(&call->a_args.cookie);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
243 dprintk("lockd: created block %p...\n", block);
244
245 /* Create and initialize the block */
246 block->b_daemon = rqstp->rq_server;
247 block->b_host = host;
248 block->b_file = file;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500249 block->b_fl = NULL;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500250 file->f_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
252 /* Add to file's list of blocks */
Olaf Kirch68a2d762006-10-04 02:15:57 -0700253 list_add(&block->b_flist, &file->f_blocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255 /* Set up RPC arguments for callback */
Trond Myklebust92737232006-03-20 13:44:45 -0500256 block->b_call = call;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 call->a_flags = RPC_TASK_ASYNC;
Trond Myklebust92737232006-03-20 13:44:45 -0500258 call->a_block = block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
260 return block;
261
262failed_free:
263 kfree(block);
264failed:
Chuck Lever7db836d2010-12-14 15:05:42 +0000265 nlmsvc_release_call(call);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 return NULL;
267}
268
269/*
J. Bruce Fields3c61eec2008-04-07 13:05:27 -0400270 * Delete a block.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 * It is the caller's responsibility to check whether the file
272 * can be closed hereafter.
273 */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500274static int nlmsvc_unlink_block(struct nlm_block *block)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275{
Trond Myklebust09c79382006-03-20 13:44:38 -0500276 int status;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500277 dprintk("lockd: unlinking block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
279 /* Remove block from list */
Trond Myklebust92737232006-03-20 13:44:45 -0500280 status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 nlmsvc_remove_block(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500282 return status;
283}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500285static void nlmsvc_free_block(struct kref *kref)
286{
287 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
288 struct nlm_file *file = block->b_file;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500289
290 dprintk("lockd: freeing block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291
292 /* Remove block from file's list of blocks */
Neil Brown89e63ef2006-10-04 02:16:06 -0700293 mutex_lock(&file->f_mutex);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700294 list_del_init(&block->b_flist);
Neil Brown89e63ef2006-10-04 02:16:06 -0700295 mutex_unlock(&file->f_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
Trond Myklebust92737232006-03-20 13:44:45 -0500297 nlmsvc_freegrantargs(block->b_call);
Chuck Lever7db836d2010-12-14 15:05:42 +0000298 nlmsvc_release_call(block->b_call);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500299 nlm_release_file(block->b_file);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500300 kfree(block->b_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 kfree(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500302}
303
304static void nlmsvc_release_block(struct nlm_block *block)
305{
306 if (block != NULL)
307 kref_put(&block->b_count, nlmsvc_free_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308}
309
Olaf Kirchf2af7932006-10-04 02:15:59 -0700310/*
311 * Loop over all blocks and delete blocks held by
312 * a matching host.
313 */
314void nlmsvc_traverse_blocks(struct nlm_host *host,
315 struct nlm_file *file,
316 nlm_host_match_fn_t match)
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500317{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700318 struct nlm_block *block, *next;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500319
320restart:
Neil Brown89e63ef2006-10-04 02:16:06 -0700321 mutex_lock(&file->f_mutex);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700322 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
Olaf Kirchf2af7932006-10-04 02:15:59 -0700323 if (!match(block->b_host, host))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500324 continue;
Olaf Kirch68a2d762006-10-04 02:15:57 -0700325 /* Do not destroy blocks that are not on
326 * the global retry list - why? */
327 if (list_empty(&block->b_list))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500328 continue;
329 kref_get(&block->b_count);
Neil Brown89e63ef2006-10-04 02:16:06 -0700330 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500331 nlmsvc_unlink_block(block);
332 nlmsvc_release_block(block);
333 goto restart;
334 }
Neil Brown89e63ef2006-10-04 02:16:06 -0700335 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500336}
337
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338/*
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500339 * Initialize arguments for GRANTED call. The nlm_rqst structure
340 * has been cleared already.
341 */
342static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
343{
344 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
345 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
Serge E. Hallyne9ff3992006-10-02 02:18:11 -0700346 call->a_args.lock.caller = utsname()->nodename;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500347 call->a_args.lock.oh.len = lock->oh.len;
348
349 /* set default data area */
350 call->a_args.lock.oh.data = call->a_owner;
351 call->a_args.lock.svid = lock->fl.fl_pid;
352
353 if (lock->oh.len > NLMCLNT_OHSIZE) {
354 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
Trond Myklebust92737232006-03-20 13:44:45 -0500355 if (!data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500356 return 0;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500357 call->a_args.lock.oh.data = (u8 *) data;
358 }
359
360 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
361 return 1;
362}
363
364static void nlmsvc_freegrantargs(struct nlm_rqst *call)
365{
Trond Myklebust92737232006-03-20 13:44:45 -0500366 if (call->a_args.lock.oh.data != call->a_owner)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500367 kfree(call->a_args.lock.oh.data);
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500368
369 locks_release_private(&call->a_args.lock.fl);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500370}
371
372/*
Marc Eshel2b36f412006-11-28 16:26:47 -0500373 * Deferred lock request handling for non-blocking lock
374 */
Al Viroca5c8cd2007-07-26 17:33:49 +0100375static __be32
Marc Eshel2b36f412006-11-28 16:26:47 -0500376nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
377{
Al Viroca5c8cd2007-07-26 17:33:49 +0100378 __be32 status = nlm_lck_denied_nolocks;
Marc Eshel2b36f412006-11-28 16:26:47 -0500379
380 block->b_flags |= B_QUEUED;
381
382 nlmsvc_insert_block(block, NLM_TIMEOUT);
383
384 block->b_cache_req = &rqstp->rq_chandle;
385 if (rqstp->rq_chandle.defer) {
386 block->b_deferred_req =
387 rqstp->rq_chandle.defer(block->b_cache_req);
388 if (block->b_deferred_req != NULL)
389 status = nlm_drop_reply;
390 }
391 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
Al Viroca5c8cd2007-07-26 17:33:49 +0100392 block, block->b_flags, ntohl(status));
Marc Eshel2b36f412006-11-28 16:26:47 -0500393
394 return status;
395}
396
397/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 * Attempt to establish a lock, and if it can't be granted, block it
399 * if required.
400 */
Al Viro52921e02006-10-19 23:28:46 -0700401__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton6cde4de2008-07-15 14:26:17 -0400403 struct nlm_host *host, struct nlm_lock *lock, int wait,
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500404 struct nlm_cookie *cookie, int reclaim)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405{
Marc Eshelf8120482006-12-05 23:48:10 -0500406 struct nlm_block *block = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 int error;
Al Viro52921e02006-10-19 23:28:46 -0700408 __be32 ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409
410 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800411 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
412 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 lock->fl.fl_type, lock->fl.fl_pid,
414 (long long)lock->fl.fl_start,
415 (long long)lock->fl.fl_end,
416 wait);
417
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 /* Lock file against concurrent access */
Neil Brown89e63ef2006-10-04 02:16:06 -0700419 mutex_lock(&file->f_mutex);
Marc Eshelf8120482006-12-05 23:48:10 -0500420 /* Get existing block (in case client is busy-waiting)
421 * or create new block
422 */
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500423 block = nlmsvc_lookup_block(file, lock);
Trond Myklebust09c79382006-03-20 13:44:38 -0500424 if (block == NULL) {
J. Bruce Fields560de0e2008-07-15 15:05:45 -0400425 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshelf8120482006-12-05 23:48:10 -0500426 ret = nlm_lck_denied_nolocks;
427 if (block == NULL)
428 goto out;
Trond Myklebust92737232006-03-20 13:44:45 -0500429 lock = &block->b_call->a_args.lock;
Marc Eshelf8120482006-12-05 23:48:10 -0500430 } else
431 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
Marc Eshel1a8322b2006-11-28 16:27:06 -0500433 if (block->b_flags & B_QUEUED) {
434 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
435 block, block->b_flags);
436 if (block->b_granted) {
437 nlmsvc_unlink_block(block);
438 ret = nlm_granted;
439 goto out;
440 }
441 if (block->b_flags & B_TIMED_OUT) {
442 nlmsvc_unlink_block(block);
443 ret = nlm_lck_denied;
444 goto out;
445 }
446 ret = nlm_drop_reply;
447 goto out;
448 }
449
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500450 if (locks_in_grace() && !reclaim) {
451 ret = nlm_lck_denied_grace_period;
452 goto out;
453 }
J. Bruce Fieldsd22b1cf2008-02-06 15:05:12 -0500454 if (reclaim && !locks_in_grace()) {
455 ret = nlm_lck_denied_grace_period;
456 goto out;
457 }
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500458
Marc Eshel1a8322b2006-11-28 16:27:06 -0500459 if (!wait)
460 lock->fl.fl_flags &= ~FL_SLEEP;
461 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500462 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463
Marc Eshel1a8322b2006-11-28 16:27:06 -0500464 dprintk("lockd: vfs_lock_file returned %d\n", error);
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400465 switch (error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 case 0:
Andy Adamson15dadef2006-03-20 13:44:24 -0500467 ret = nlm_granted;
468 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500469 case -EAGAIN:
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500470 /*
471 * If this is a blocking request for an
472 * already pending lock request then we need
473 * to put it back on lockd's block list
474 */
475 if (wait)
476 break;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500477 ret = nlm_lck_denied;
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500478 goto out;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700479 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500480 if (wait)
481 break;
482 /* Filesystem lock operation is in progress
483 Add it to the queue waiting for callback */
484 ret = nlmsvc_defer_lock_rqst(rqstp, block);
485 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500486 case -EDEADLK:
Andy Adamson15dadef2006-03-20 13:44:24 -0500487 ret = nlm_deadlock;
488 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 default: /* includes ENOLCK */
Andy Adamson15dadef2006-03-20 13:44:24 -0500490 ret = nlm_lck_denied_nolocks;
491 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 }
493
Trond Myklebust09c79382006-03-20 13:44:38 -0500494 ret = nlm_lck_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
496 /* Append to list of blocked */
Marc Eshelf8120482006-12-05 23:48:10 -0500497 nlmsvc_insert_block(block, NLM_NEVER);
Andy Adamson15dadef2006-03-20 13:44:24 -0500498out:
Neil Brown89e63ef2006-10-04 02:16:06 -0700499 mutex_unlock(&file->f_mutex);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500500 nlmsvc_release_block(block);
Andy Adamson15dadef2006-03-20 13:44:24 -0500501 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
502 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503}
504
505/*
506 * Test for presence of a conflicting lock.
507 */
Al Viro52921e02006-10-19 23:28:46 -0700508__be32
Marc Eshel85f3f1b32006-11-28 16:27:06 -0500509nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton8f920d52008-07-15 14:06:48 -0400510 struct nlm_host *host, struct nlm_lock *lock,
511 struct nlm_lock *conflock, struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512{
Marc Eshel5ea0d752006-11-28 16:27:06 -0500513 struct nlm_block *block = NULL;
514 int error;
515 __be32 ret;
516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800518 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
519 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 lock->fl.fl_type,
521 (long long)lock->fl.fl_start,
522 (long long)lock->fl.fl_end);
523
Marc Eshel5ea0d752006-11-28 16:27:06 -0500524 /* Get existing block (in case client is busy-waiting) */
525 block = nlmsvc_lookup_block(file, lock);
526
527 if (block == NULL) {
528 struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
529
530 if (conf == NULL)
531 return nlm_granted;
Trond Myklebust255129d2007-09-25 15:55:03 -0400532 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500533 if (block == NULL) {
534 kfree(conf);
535 return nlm_granted;
536 }
537 block->b_fl = conf;
538 }
539 if (block->b_flags & B_QUEUED) {
540 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
541 block, block->b_flags, block->b_fl);
542 if (block->b_flags & B_TIMED_OUT) {
543 nlmsvc_unlink_block(block);
Oleg Drokin29dbf542007-11-29 14:02:21 -0500544 ret = nlm_lck_denied;
545 goto out;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500546 }
547 if (block->b_flags & B_GOT_CALLBACK) {
Oleg Drokin54ca95e2008-01-11 21:57:35 -0500548 nlmsvc_unlink_block(block);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500549 if (block->b_fl != NULL
550 && block->b_fl->fl_type != F_UNLCK) {
551 lock->fl = *block->b_fl;
552 goto conf_lock;
Oleg Drokin29dbf542007-11-29 14:02:21 -0500553 } else {
Oleg Drokin29dbf542007-11-29 14:02:21 -0500554 ret = nlm_granted;
555 goto out;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500556 }
557 }
Oleg Drokin29dbf542007-11-29 14:02:21 -0500558 ret = nlm_drop_reply;
559 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 }
561
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500562 if (locks_in_grace()) {
563 ret = nlm_lck_denied_grace_period;
564 goto out;
565 }
Marc Eshel5ea0d752006-11-28 16:27:06 -0500566 error = vfs_test_lock(file->f_file, &lock->fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -0700567 if (error == FILE_LOCK_DEFERRED) {
Oleg Drokin29dbf542007-11-29 14:02:21 -0500568 ret = nlmsvc_defer_lock_rqst(rqstp, block);
569 goto out;
570 }
Marc Eshel5ea0d752006-11-28 16:27:06 -0500571 if (error) {
572 ret = nlm_lck_denied_nolocks;
573 goto out;
574 }
575 if (lock->fl.fl_type == F_UNLCK) {
576 ret = nlm_granted;
577 goto out;
578 }
579
580conf_lock:
581 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
582 lock->fl.fl_type, (long long)lock->fl.fl_start,
583 (long long)lock->fl.fl_end);
584 conflock->caller = "somehost"; /* FIXME */
585 conflock->len = strlen(conflock->caller);
586 conflock->oh.len = 0; /* don't return OH info */
587 conflock->svid = lock->fl.fl_pid;
588 conflock->fl.fl_type = lock->fl.fl_type;
589 conflock->fl.fl_start = lock->fl.fl_start;
590 conflock->fl.fl_end = lock->fl.fl_end;
591 ret = nlm_lck_denied;
592out:
593 if (block)
594 nlmsvc_release_block(block);
595 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596}
597
598/*
599 * Remove a lock.
600 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
601 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
602 * afterwards. In this case the block will still be there, and hence
603 * must be removed.
604 */
Al Viro52921e02006-10-19 23:28:46 -0700605__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
607{
608 int error;
609
610 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800611 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
612 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 lock->fl.fl_pid,
614 (long long)lock->fl.fl_start,
615 (long long)lock->fl.fl_end);
616
617 /* First, cancel any lock that might be there */
618 nlmsvc_cancel_blocked(file, lock);
619
620 lock->fl.fl_type = F_UNLCK;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500621 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622
623 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
624}
625
626/*
627 * Cancel a previously blocked request.
628 *
629 * A cancel request always overrides any grant that may currently
630 * be in progress.
631 * The calling procedure must check whether the file can be closed.
632 */
Al Viro52921e02006-10-19 23:28:46 -0700633__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
635{
636 struct nlm_block *block;
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100637 int status = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638
639 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
Josef Sipek225a7192006-12-08 02:37:18 -0800640 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
641 file->f_file->f_path.dentry->d_inode->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 lock->fl.fl_pid,
643 (long long)lock->fl.fl_start,
644 (long long)lock->fl.fl_end);
645
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500646 if (locks_in_grace())
647 return nlm_lck_denied_grace_period;
648
Neil Brown89e63ef2006-10-04 02:16:06 -0700649 mutex_lock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500650 block = nlmsvc_lookup_block(file, lock);
Neil Brown89e63ef2006-10-04 02:16:06 -0700651 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500652 if (block != NULL) {
Marc Eshel1a8322b2006-11-28 16:27:06 -0500653 vfs_cancel_lock(block->b_file->f_file,
654 &block->b_call->a_args.lock.fl);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500655 status = nlmsvc_unlink_block(block);
656 nlmsvc_release_block(block);
657 }
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100658 return status ? nlm_lck_denied : nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659}
660
661/*
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500662 * This is a callback from the filesystem for VFS file lock requests.
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400663 * It will be used if lm_grant is defined and the filesystem can not
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500664 * respond to the request immediately.
665 * For GETLK request it will copy the reply to the nlm_block.
666 * For SETLK or SETLKW request it will get the local posix lock.
667 * In all cases it will move the block to the head of nlm_blocked q where
668 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
669 * deferred rpc for GETLK and SETLK.
670 */
671static void
672nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf,
673 int result)
674{
675 block->b_flags |= B_GOT_CALLBACK;
676 if (result == 0)
677 block->b_granted = 1;
678 else
679 block->b_flags |= B_TIMED_OUT;
680 if (conf) {
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500681 if (block->b_fl)
J. Bruce Fields1a747ee2008-04-24 10:08:22 -0400682 __locks_copy_lock(block->b_fl, conf);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500683 }
684}
685
686static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
687 int result)
688{
689 struct nlm_block *block;
690 int rc = -ENOENT;
691
Bryan Schumakerf904be92010-09-21 16:38:12 -0400692 spin_lock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500693 list_for_each_entry(block, &nlm_blocked, b_list) {
694 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
695 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
696 block, block->b_flags);
697 if (block->b_flags & B_QUEUED) {
698 if (block->b_flags & B_TIMED_OUT) {
699 rc = -ENOLCK;
700 break;
701 }
702 nlmsvc_update_deferred_block(block, conf, result);
703 } else if (result == 0)
704 block->b_granted = 1;
705
Bryan Schumakerf904be92010-09-21 16:38:12 -0400706 nlmsvc_insert_block_locked(block, 0);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500707 svc_wake_up(block->b_daemon);
708 rc = 0;
709 break;
710 }
711 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400712 spin_unlock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500713 if (rc == -ENOENT)
714 printk(KERN_WARNING "lockd: grant for unknown block\n");
715 return rc;
716}
717
718/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 * Unblock a blocked lock request. This is a callback invoked from the
720 * VFS layer when a lock on which we blocked is removed.
721 *
722 * This function doesn't grant the blocked lock instantly, but rather moves
723 * the block to the head of nlm_blocked where it can be picked up by lockd.
724 */
725static void
726nlmsvc_notify_blocked(struct file_lock *fl)
727{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700728 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729
730 dprintk("lockd: VFS unblock notification for block %p\n", fl);
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400731 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700732 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust92737232006-03-20 13:44:45 -0500733 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400734 nlmsvc_insert_block_locked(block, 0);
735 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 svc_wake_up(block->b_daemon);
737 return;
738 }
739 }
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400740 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 printk(KERN_WARNING "lockd: notification for unknown block!\n");
742}
743
744static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
745{
746 return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
747}
748
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700749const struct lock_manager_operations nlmsvc_lock_operations = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400750 .lm_compare_owner = nlmsvc_same_owner,
751 .lm_notify = nlmsvc_notify_blocked,
752 .lm_grant = nlmsvc_grant_deferred,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753};
754
755/*
756 * Try to claim a lock that was previously blocked.
757 *
758 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
759 * RPC thread when notifying the client. This seems like overkill...
760 * Here's why:
761 * - we don't want to use a synchronous RPC thread, otherwise
762 * we might find ourselves hanging on a dead portmapper.
763 * - Some lockd implementations (e.g. HP) don't react to
764 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
765 */
766static void
767nlmsvc_grant_blocked(struct nlm_block *block)
768{
769 struct nlm_file *file = block->b_file;
Trond Myklebust92737232006-03-20 13:44:45 -0500770 struct nlm_lock *lock = &block->b_call->a_args.lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 int error;
772
773 dprintk("lockd: grant blocked lock %p\n", block);
774
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500775 kref_get(&block->b_count);
776
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 /* Unlink block request from list */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500778 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779
780 /* If b_granted is true this means we've been here before.
781 * Just retry the grant callback, possibly refreshing the RPC
782 * binding */
783 if (block->b_granted) {
784 nlm_rebind_host(block->b_host);
785 goto callback;
786 }
787
788 /* Try the lock operation again */
Trond Myklebust09c79382006-03-20 13:44:38 -0500789 lock->fl.fl_flags |= FL_SLEEP;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500790 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500791 lock->fl.fl_flags &= ~FL_SLEEP;
792
Andy Adamson5de0e502006-03-20 13:44:25 -0500793 switch (error) {
794 case 0:
795 break;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700796 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500797 dprintk("lockd: lock still blocked error %d\n", error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 nlmsvc_insert_block(block, NLM_NEVER);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500799 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500800 return;
Andy Adamson5de0e502006-03-20 13:44:25 -0500801 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700803 -error, __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 nlmsvc_insert_block(block, 10 * HZ);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500805 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500806 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 }
808
809callback:
810 /* Lock was granted by VFS. */
811 dprintk("lockd: GRANTing blocked lock.\n");
812 block->b_granted = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813
Jeff Layton97065012008-02-06 11:34:12 -0500814 /* keep block on the list, but don't reattempt until the RPC
815 * completes or the submission fails
816 */
817 nlmsvc_insert_block(block, NLM_NEVER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818
Jeff Layton97065012008-02-06 11:34:12 -0500819 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
820 * will queue up a new one if this one times out
821 */
822 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
823 &nlmsvc_grant_ops);
824
825 /* RPC submission failed, wait a bit and retry */
826 if (error < 0)
827 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828}
829
830/*
831 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
832 * RPC call has succeeded or timed out.
833 * Like all RPC callbacks, it is invoked by the rpciod process, so it
834 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
835 * chain once more in order to have it removed by lockd itself (which can
836 * then sleep on the file semaphore without disrupting e.g. the nfs client).
837 */
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100838static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839{
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100840 struct nlm_rqst *call = data;
Trond Myklebust92737232006-03-20 13:44:45 -0500841 struct nlm_block *block = call->a_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 unsigned long timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843
844 dprintk("lockd: GRANT_MSG RPC callback\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
Bryan Schumakerf904be92010-09-21 16:38:12 -0400846 spin_lock(&nlm_blocked_lock);
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500847 /* if the block is not on a list at this point then it has
848 * been invalidated. Don't try to requeue it.
849 *
850 * FIXME: it's possible that the block is removed from the list
851 * after this check but before the nlmsvc_insert_block. In that
852 * case it will be added back. Perhaps we need better locking
853 * for nlm_blocked?
854 */
855 if (list_empty(&block->b_list))
Trond Myklebusta86dc492008-06-11 13:37:09 -0400856 goto out;
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500857
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 /* Technically, we should down the file semaphore here. Since we
859 * move the block towards the head of the queue only, no harm
860 * can be done, though. */
861 if (task->tk_status < 0) {
862 /* RPC error: Re-insert for retransmission */
863 timeout = 10 * HZ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 } else {
865 /* Call was successful, now wait for client callback */
866 timeout = 60 * HZ;
867 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400868 nlmsvc_insert_block_locked(block, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 svc_wake_up(block->b_daemon);
Trond Myklebusta86dc492008-06-11 13:37:09 -0400870out:
Bryan Schumakerf904be92010-09-21 16:38:12 -0400871 spin_unlock(&nlm_blocked_lock);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500872}
873
Bryan Schumakerf904be92010-09-21 16:38:12 -0400874/*
875 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
876 * .rpc_release rpc_call_op
877 */
Adrian Bunkec535ce2006-04-18 13:21:50 -0400878static void nlmsvc_grant_release(void *data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500879{
Trond Myklebust6041b792006-03-20 13:44:45 -0500880 struct nlm_rqst *call = data;
Trond Myklebust6041b792006-03-20 13:44:45 -0500881 nlmsvc_release_block(call->a_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882}
883
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100884static const struct rpc_call_ops nlmsvc_grant_ops = {
885 .rpc_call_done = nlmsvc_grant_callback,
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500886 .rpc_release = nlmsvc_grant_release,
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100887};
888
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889/*
890 * We received a GRANT_RES callback. Try to find the corresponding
891 * block.
892 */
893void
Al Viroe8c5c042006-12-13 00:35:03 -0800894nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895{
896 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
Olaf Kirch39be4502006-10-04 02:16:03 -0700898 dprintk("grant_reply: looking for cookie %x, s=%d \n",
899 *(unsigned int *)(cookie->data), status);
900 if (!(block = nlmsvc_find_block(cookie)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902
J. Bruce Fieldsf2321422006-01-03 09:55:42 +0100903 if (block) {
Al Viroe8c5c042006-12-13 00:35:03 -0800904 if (status == nlm_lck_denied_grace_period) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 /* Try again in a couple of seconds */
906 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 } else {
908 /* Lock is now held by client, or has been rejected.
909 * In both cases, the block should be removed. */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500910 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 }
912 }
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500913 nlmsvc_release_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914}
915
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500916/* Helper function to handle retry of a deferred block.
917 * If it is a blocking lock, call grant_blocked.
918 * For a non-blocking lock or test lock, revisit the request.
919 */
920static void
921retry_deferred_block(struct nlm_block *block)
922{
923 if (!(block->b_flags & B_GOT_CALLBACK))
924 block->b_flags |= B_TIMED_OUT;
925 nlmsvc_insert_block(block, NLM_TIMEOUT);
926 dprintk("revisit block %p flags %d\n", block, block->b_flags);
927 if (block->b_deferred_req) {
928 block->b_deferred_req->revisit(block->b_deferred_req, 0);
929 block->b_deferred_req = NULL;
930 }
931}
932
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933/*
934 * Retry all blocked locks that have been notified. This is where lockd
935 * picks up locks that can be granted, or grant notifications that must
936 * be retransmitted.
937 */
938unsigned long
939nlmsvc_retry_blocked(void)
940{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700941 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
942 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943
Jeff Laytond751a7c2008-02-07 16:34:55 -0500944 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
Olaf Kirch68a2d762006-10-04 02:15:57 -0700945 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
946
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 if (block->b_when == NLM_NEVER)
948 break;
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400949 if (time_after(block->b_when, jiffies)) {
Olaf Kirch68a2d762006-10-04 02:15:57 -0700950 timeout = block->b_when - jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 break;
Olaf Kirch68a2d762006-10-04 02:15:57 -0700952 }
953
J. Bruce Fieldsf3d43c72006-08-03 15:07:47 -0400954 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
955 block, block->b_when);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500956 if (block->b_flags & B_QUEUED) {
957 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
958 block, block->b_granted, block->b_flags);
959 retry_deferred_block(block);
960 } else
961 nlmsvc_grant_blocked(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 }
963
Olaf Kirch68a2d762006-10-04 02:15:57 -0700964 return timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965}