blob: 5581e020644bda687f0b4bd09645a058a18d4537 [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>
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +040029#include <linux/sunrpc/svc_xprt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#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
Jeff Layton10b89562014-11-17 16:58:03 -050056#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
Trond Myklebustffa94db2012-03-20 09:22:00 -040057static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
58{
59 /*
Jeff Layton3c519912015-01-22 08:19:32 -050060 * We can get away with a static buffer because this is only called
61 * from lockd, which is single-threaded.
Trond Myklebustffa94db2012-03-20 09:22:00 -040062 */
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
Trond Myklebust92737232006-03-20 13:44:45 -0500222 call = nlm_alloc_call(host);
223 if (call == NULL)
224 return NULL;
225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 /* Allocate memory for block, and initialize arguments */
Trond Myklebust92737232006-03-20 13:44:45 -0500227 block = kzalloc(sizeof(*block), GFP_KERNEL);
228 if (block == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 goto failed;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500230 kref_init(&block->b_count);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700231 INIT_LIST_HEAD(&block->b_list);
232 INIT_LIST_HEAD(&block->b_flist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Trond Myklebust92737232006-03-20 13:44:45 -0500234 if (!nlmsvc_setgrantargs(call, lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 goto failed_free;
236
237 /* Set notifier function for VFS, and init args */
Trond Myklebust92737232006-03-20 13:44:45 -0500238 call->a_args.lock.fl.fl_flags |= FL_SLEEP;
239 call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
Olaf Kirch39be4502006-10-04 02:16:03 -0700240 nlmclnt_next_cookie(&call->a_args.cookie);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
242 dprintk("lockd: created block %p...\n", block);
243
244 /* Create and initialize the block */
245 block->b_daemon = rqstp->rq_server;
246 block->b_host = host;
247 block->b_file = file;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500248 file->f_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
250 /* Add to file's list of blocks */
Olaf Kirch68a2d762006-10-04 02:15:57 -0700251 list_add(&block->b_flist, &file->f_blocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 /* Set up RPC arguments for callback */
Trond Myklebust92737232006-03-20 13:44:45 -0500254 block->b_call = call;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 call->a_flags = RPC_TASK_ASYNC;
Trond Myklebust92737232006-03-20 13:44:45 -0500256 call->a_block = block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 return block;
259
260failed_free:
261 kfree(block);
262failed:
Chuck Lever7db836d2010-12-14 15:05:42 +0000263 nlmsvc_release_call(call);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 return NULL;
265}
266
267/*
J. Bruce Fields3c61eec2008-04-07 13:05:27 -0400268 * Delete a block.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 * It is the caller's responsibility to check whether the file
270 * can be closed hereafter.
271 */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500272static int nlmsvc_unlink_block(struct nlm_block *block)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273{
Trond Myklebust09c79382006-03-20 13:44:38 -0500274 int status;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500275 dprintk("lockd: unlinking block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
277 /* Remove block from list */
Jeff Laytonf891a292013-06-21 08:58:09 -0400278 status = posix_unblock_lock(&block->b_call->a_args.lock.fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 nlmsvc_remove_block(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500280 return status;
281}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500283static void nlmsvc_free_block(struct kref *kref)
284{
285 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
286 struct nlm_file *file = block->b_file;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500287
288 dprintk("lockd: freeing block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
290 /* Remove block from file's list of blocks */
Olaf Kirch68a2d762006-10-04 02:15:57 -0700291 list_del_init(&block->b_flist);
Neil Brown89e63ef2006-10-04 02:16:06 -0700292 mutex_unlock(&file->f_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Trond Myklebust92737232006-03-20 13:44:45 -0500294 nlmsvc_freegrantargs(block->b_call);
Chuck Lever7db836d2010-12-14 15:05:42 +0000295 nlmsvc_release_call(block->b_call);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500296 nlm_release_file(block->b_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 kfree(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500298}
299
300static void nlmsvc_release_block(struct nlm_block *block)
301{
302 if (block != NULL)
Al Viroc5aa1e52012-08-29 09:00:01 -0400303 kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304}
305
Olaf Kirchf2af7932006-10-04 02:15:59 -0700306/*
307 * Loop over all blocks and delete blocks held by
308 * a matching host.
309 */
310void nlmsvc_traverse_blocks(struct nlm_host *host,
311 struct nlm_file *file,
312 nlm_host_match_fn_t match)
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500313{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700314 struct nlm_block *block, *next;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500315
316restart:
Neil Brown89e63ef2006-10-04 02:16:06 -0700317 mutex_lock(&file->f_mutex);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700318 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
Olaf Kirchf2af7932006-10-04 02:15:59 -0700319 if (!match(block->b_host, host))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500320 continue;
Olaf Kirch68a2d762006-10-04 02:15:57 -0700321 /* Do not destroy blocks that are not on
322 * the global retry list - why? */
323 if (list_empty(&block->b_list))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500324 continue;
325 kref_get(&block->b_count);
Neil Brown89e63ef2006-10-04 02:16:06 -0700326 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500327 nlmsvc_unlink_block(block);
328 nlmsvc_release_block(block);
329 goto restart;
330 }
Neil Brown89e63ef2006-10-04 02:16:06 -0700331 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500332}
333
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334/*
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500335 * Initialize arguments for GRANTED call. The nlm_rqst structure
336 * has been cleared already.
337 */
338static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
339{
340 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
341 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
Serge E. Hallyne9ff3992006-10-02 02:18:11 -0700342 call->a_args.lock.caller = utsname()->nodename;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500343 call->a_args.lock.oh.len = lock->oh.len;
344
345 /* set default data area */
346 call->a_args.lock.oh.data = call->a_owner;
347 call->a_args.lock.svid = lock->fl.fl_pid;
348
349 if (lock->oh.len > NLMCLNT_OHSIZE) {
350 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
Trond Myklebust92737232006-03-20 13:44:45 -0500351 if (!data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500352 return 0;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500353 call->a_args.lock.oh.data = (u8 *) data;
354 }
355
356 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
357 return 1;
358}
359
360static void nlmsvc_freegrantargs(struct nlm_rqst *call)
361{
Trond Myklebust92737232006-03-20 13:44:45 -0500362 if (call->a_args.lock.oh.data != call->a_owner)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500363 kfree(call->a_args.lock.oh.data);
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500364
365 locks_release_private(&call->a_args.lock.fl);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500366}
367
368/*
Marc Eshel2b36f412006-11-28 16:26:47 -0500369 * Deferred lock request handling for non-blocking lock
370 */
Al Viroca5c8cd2007-07-26 17:33:49 +0100371static __be32
Marc Eshel2b36f412006-11-28 16:26:47 -0500372nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
373{
Al Viroca5c8cd2007-07-26 17:33:49 +0100374 __be32 status = nlm_lck_denied_nolocks;
Marc Eshel2b36f412006-11-28 16:26:47 -0500375
376 block->b_flags |= B_QUEUED;
377
378 nlmsvc_insert_block(block, NLM_TIMEOUT);
379
380 block->b_cache_req = &rqstp->rq_chandle;
381 if (rqstp->rq_chandle.defer) {
382 block->b_deferred_req =
383 rqstp->rq_chandle.defer(block->b_cache_req);
384 if (block->b_deferred_req != NULL)
385 status = nlm_drop_reply;
386 }
387 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
Al Viroca5c8cd2007-07-26 17:33:49 +0100388 block, block->b_flags, ntohl(status));
Marc Eshel2b36f412006-11-28 16:26:47 -0500389
390 return status;
391}
392
393/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 * Attempt to establish a lock, and if it can't be granted, block it
395 * if required.
396 */
Al Viro52921e02006-10-19 23:28:46 -0700397__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton6cde4de2008-07-15 14:26:17 -0400399 struct nlm_host *host, struct nlm_lock *lock, int wait,
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500400 struct nlm_cookie *cookie, int reclaim)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401{
Marc Eshelf8120482006-12-05 23:48:10 -0500402 struct nlm_block *block = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 int error;
Al Viro52921e02006-10-19 23:28:46 -0700404 __be32 ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405
406 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500407 file_inode(file->f_file)->i_sb->s_id,
408 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 lock->fl.fl_type, lock->fl.fl_pid,
410 (long long)lock->fl.fl_start,
411 (long long)lock->fl.fl_end,
412 wait);
413
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 /* Lock file against concurrent access */
Neil Brown89e63ef2006-10-04 02:16:06 -0700415 mutex_lock(&file->f_mutex);
Marc Eshelf8120482006-12-05 23:48:10 -0500416 /* Get existing block (in case client is busy-waiting)
417 * or create new block
418 */
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500419 block = nlmsvc_lookup_block(file, lock);
Trond Myklebust09c79382006-03-20 13:44:38 -0500420 if (block == NULL) {
J. Bruce Fields560de0e2008-07-15 15:05:45 -0400421 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshelf8120482006-12-05 23:48:10 -0500422 ret = nlm_lck_denied_nolocks;
423 if (block == NULL)
424 goto out;
Trond Myklebust92737232006-03-20 13:44:45 -0500425 lock = &block->b_call->a_args.lock;
Marc Eshelf8120482006-12-05 23:48:10 -0500426 } else
427 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428
Marc Eshel1a8322b2006-11-28 16:27:06 -0500429 if (block->b_flags & B_QUEUED) {
430 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
431 block, block->b_flags);
432 if (block->b_granted) {
433 nlmsvc_unlink_block(block);
434 ret = nlm_granted;
435 goto out;
436 }
437 if (block->b_flags & B_TIMED_OUT) {
438 nlmsvc_unlink_block(block);
439 ret = nlm_lck_denied;
440 goto out;
441 }
442 ret = nlm_drop_reply;
443 goto out;
444 }
445
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400446 if (locks_in_grace(SVC_NET(rqstp)) && !reclaim) {
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500447 ret = nlm_lck_denied_grace_period;
448 goto out;
449 }
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400450 if (reclaim && !locks_in_grace(SVC_NET(rqstp))) {
J. Bruce Fieldsd22b1cf2008-02-06 15:05:12 -0500451 ret = nlm_lck_denied_grace_period;
452 goto out;
453 }
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500454
Marc Eshel1a8322b2006-11-28 16:27:06 -0500455 if (!wait)
456 lock->fl.fl_flags &= ~FL_SLEEP;
457 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500458 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459
Marc Eshel1a8322b2006-11-28 16:27:06 -0500460 dprintk("lockd: vfs_lock_file returned %d\n", error);
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400461 switch (error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 case 0:
Andy Adamson15dadef2006-03-20 13:44:24 -0500463 ret = nlm_granted;
464 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500465 case -EAGAIN:
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500466 /*
467 * If this is a blocking request for an
468 * already pending lock request then we need
469 * to put it back on lockd's block list
470 */
471 if (wait)
472 break;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500473 ret = nlm_lck_denied;
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500474 goto out;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700475 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500476 if (wait)
477 break;
478 /* Filesystem lock operation is in progress
479 Add it to the queue waiting for callback */
480 ret = nlmsvc_defer_lock_rqst(rqstp, block);
481 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500482 case -EDEADLK:
Andy Adamson15dadef2006-03-20 13:44:24 -0500483 ret = nlm_deadlock;
484 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 default: /* includes ENOLCK */
Andy Adamson15dadef2006-03-20 13:44:24 -0500486 ret = nlm_lck_denied_nolocks;
487 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 }
489
Trond Myklebust09c79382006-03-20 13:44:38 -0500490 ret = nlm_lck_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491
492 /* Append to list of blocked */
Marc Eshelf8120482006-12-05 23:48:10 -0500493 nlmsvc_insert_block(block, NLM_NEVER);
Andy Adamson15dadef2006-03-20 13:44:24 -0500494out:
Neil Brown89e63ef2006-10-04 02:16:06 -0700495 mutex_unlock(&file->f_mutex);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500496 nlmsvc_release_block(block);
Andy Adamson15dadef2006-03-20 13:44:24 -0500497 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
498 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499}
500
501/*
502 * Test for presence of a conflicting lock.
503 */
Al Viro52921e02006-10-19 23:28:46 -0700504__be32
Marc Eshel85f3f1b32006-11-28 16:27:06 -0500505nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton8f920d52008-07-15 14:06:48 -0400506 struct nlm_host *host, struct nlm_lock *lock,
507 struct nlm_lock *conflock, struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508{
Marc Eshel5ea0d752006-11-28 16:27:06 -0500509 int error;
510 __be32 ret;
511
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500513 file_inode(file->f_file)->i_sb->s_id,
514 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 lock->fl.fl_type,
516 (long long)lock->fl.fl_start,
517 (long long)lock->fl.fl_end);
518
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400519 if (locks_in_grace(SVC_NET(rqstp))) {
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500520 ret = nlm_lck_denied_grace_period;
521 goto out;
522 }
Jeff Layton09802fd2014-08-22 10:18:44 -0400523
Marc Eshel5ea0d752006-11-28 16:27:06 -0500524 error = vfs_test_lock(file->f_file, &lock->fl);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500525 if (error) {
Jeff Layton09802fd2014-08-22 10:18:44 -0400526 /* We can't currently deal with deferred test requests */
527 if (error == FILE_LOCK_DEFERRED)
528 WARN_ON_ONCE(1);
529
Marc Eshel5ea0d752006-11-28 16:27:06 -0500530 ret = nlm_lck_denied_nolocks;
531 goto out;
532 }
Jeff Layton09802fd2014-08-22 10:18:44 -0400533
Marc Eshel5ea0d752006-11-28 16:27:06 -0500534 if (lock->fl.fl_type == F_UNLCK) {
535 ret = nlm_granted;
536 goto out;
537 }
538
Marc Eshel5ea0d752006-11-28 16:27:06 -0500539 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
540 lock->fl.fl_type, (long long)lock->fl.fl_start,
541 (long long)lock->fl.fl_end);
542 conflock->caller = "somehost"; /* FIXME */
543 conflock->len = strlen(conflock->caller);
544 conflock->oh.len = 0; /* don't return OH info */
545 conflock->svid = lock->fl.fl_pid;
546 conflock->fl.fl_type = lock->fl.fl_type;
547 conflock->fl.fl_start = lock->fl.fl_start;
548 conflock->fl.fl_end = lock->fl.fl_end;
Kinglong Meef3282962014-08-22 10:18:43 -0400549 locks_release_private(&lock->fl);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500550 ret = nlm_lck_denied;
551out:
Marc Eshel5ea0d752006-11-28 16:27:06 -0500552 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553}
554
555/*
556 * Remove a lock.
557 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
558 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
559 * afterwards. In this case the block will still be there, and hence
560 * must be removed.
561 */
Al Viro52921e02006-10-19 23:28:46 -0700562__be32
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400563nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564{
565 int error;
566
567 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500568 file_inode(file->f_file)->i_sb->s_id,
569 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 lock->fl.fl_pid,
571 (long long)lock->fl.fl_start,
572 (long long)lock->fl.fl_end);
573
574 /* First, cancel any lock that might be there */
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400575 nlmsvc_cancel_blocked(net, file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576
577 lock->fl.fl_type = F_UNLCK;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500578 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579
580 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
581}
582
583/*
584 * Cancel a previously blocked request.
585 *
586 * A cancel request always overrides any grant that may currently
587 * be in progress.
588 * The calling procedure must check whether the file can be closed.
589 */
Al Viro52921e02006-10-19 23:28:46 -0700590__be32
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400591nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592{
593 struct nlm_block *block;
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100594 int status = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595
596 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500597 file_inode(file->f_file)->i_sb->s_id,
598 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 lock->fl.fl_pid,
600 (long long)lock->fl.fl_start,
601 (long long)lock->fl.fl_end);
602
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400603 if (locks_in_grace(net))
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500604 return nlm_lck_denied_grace_period;
605
Neil Brown89e63ef2006-10-04 02:16:06 -0700606 mutex_lock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500607 block = nlmsvc_lookup_block(file, lock);
Neil Brown89e63ef2006-10-04 02:16:06 -0700608 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500609 if (block != NULL) {
Marc Eshel1a8322b2006-11-28 16:27:06 -0500610 vfs_cancel_lock(block->b_file->f_file,
611 &block->b_call->a_args.lock.fl);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500612 status = nlmsvc_unlink_block(block);
613 nlmsvc_release_block(block);
614 }
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100615 return status ? nlm_lck_denied : nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616}
617
618/*
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500619 * This is a callback from the filesystem for VFS file lock requests.
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400620 * It will be used if lm_grant is defined and the filesystem can not
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500621 * respond to the request immediately.
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500622 * For SETLK or SETLKW request it will get the local posix lock.
623 * In all cases it will move the block to the head of nlm_blocked q where
624 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
625 * deferred rpc for GETLK and SETLK.
626 */
627static void
Joe Perchesd0449b92014-08-22 10:18:42 -0400628nlmsvc_update_deferred_block(struct nlm_block *block, int result)
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500629{
630 block->b_flags |= B_GOT_CALLBACK;
631 if (result == 0)
632 block->b_granted = 1;
633 else
634 block->b_flags |= B_TIMED_OUT;
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500635}
636
Joe Perchesd0449b92014-08-22 10:18:42 -0400637static int nlmsvc_grant_deferred(struct file_lock *fl, int result)
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500638{
639 struct nlm_block *block;
640 int rc = -ENOENT;
641
Bryan Schumakerf904be92010-09-21 16:38:12 -0400642 spin_lock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500643 list_for_each_entry(block, &nlm_blocked, b_list) {
644 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
645 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
646 block, block->b_flags);
647 if (block->b_flags & B_QUEUED) {
648 if (block->b_flags & B_TIMED_OUT) {
649 rc = -ENOLCK;
650 break;
651 }
Joe Perchesd0449b92014-08-22 10:18:42 -0400652 nlmsvc_update_deferred_block(block, result);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500653 } else if (result == 0)
654 block->b_granted = 1;
655
Bryan Schumakerf904be92010-09-21 16:38:12 -0400656 nlmsvc_insert_block_locked(block, 0);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500657 svc_wake_up(block->b_daemon);
658 rc = 0;
659 break;
660 }
661 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400662 spin_unlock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500663 if (rc == -ENOENT)
664 printk(KERN_WARNING "lockd: grant for unknown block\n");
665 return rc;
666}
667
668/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 * Unblock a blocked lock request. This is a callback invoked from the
670 * VFS layer when a lock on which we blocked is removed.
671 *
672 * This function doesn't grant the blocked lock instantly, but rather moves
673 * the block to the head of nlm_blocked where it can be picked up by lockd.
674 */
675static void
676nlmsvc_notify_blocked(struct file_lock *fl)
677{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700678 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
680 dprintk("lockd: VFS unblock notification for block %p\n", fl);
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400681 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700682 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust92737232006-03-20 13:44:45 -0500683 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400684 nlmsvc_insert_block_locked(block, 0);
685 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 svc_wake_up(block->b_daemon);
687 return;
688 }
689 }
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400690 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 printk(KERN_WARNING "lockd: notification for unknown block!\n");
692}
693
694static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
695{
696 return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
697}
698
Jeff Layton3999e492013-06-21 08:58:19 -0400699/*
700 * Since NLM uses two "keys" for tracking locks, we need to hash them down
701 * to one for the blocked_hash. Here, we're just xor'ing the host address
702 * with the pid in order to create a key value for picking a hash bucket.
703 */
704static unsigned long
705nlmsvc_owner_key(struct file_lock *fl)
706{
707 return (unsigned long)fl->fl_owner ^ (unsigned long)fl->fl_pid;
708}
709
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700710const struct lock_manager_operations nlmsvc_lock_operations = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400711 .lm_compare_owner = nlmsvc_same_owner,
Jeff Layton3999e492013-06-21 08:58:19 -0400712 .lm_owner_key = nlmsvc_owner_key,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400713 .lm_notify = nlmsvc_notify_blocked,
714 .lm_grant = nlmsvc_grant_deferred,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715};
716
717/*
718 * Try to claim a lock that was previously blocked.
719 *
720 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
721 * RPC thread when notifying the client. This seems like overkill...
722 * Here's why:
723 * - we don't want to use a synchronous RPC thread, otherwise
724 * we might find ourselves hanging on a dead portmapper.
725 * - Some lockd implementations (e.g. HP) don't react to
726 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
727 */
728static void
729nlmsvc_grant_blocked(struct nlm_block *block)
730{
731 struct nlm_file *file = block->b_file;
Trond Myklebust92737232006-03-20 13:44:45 -0500732 struct nlm_lock *lock = &block->b_call->a_args.lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 int error;
NeilBrown2ec197d2014-02-07 17:10:26 +1100734 loff_t fl_start, fl_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735
736 dprintk("lockd: grant blocked lock %p\n", block);
737
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500738 kref_get(&block->b_count);
739
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 /* Unlink block request from list */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500741 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742
743 /* If b_granted is true this means we've been here before.
744 * Just retry the grant callback, possibly refreshing the RPC
745 * binding */
746 if (block->b_granted) {
747 nlm_rebind_host(block->b_host);
748 goto callback;
749 }
750
751 /* Try the lock operation again */
NeilBrown2ec197d2014-02-07 17:10:26 +1100752 /* vfs_lock_file() can mangle fl_start and fl_end, but we need
753 * them unchanged for the GRANT_MSG
754 */
Trond Myklebust09c79382006-03-20 13:44:38 -0500755 lock->fl.fl_flags |= FL_SLEEP;
NeilBrown2ec197d2014-02-07 17:10:26 +1100756 fl_start = lock->fl.fl_start;
757 fl_end = lock->fl.fl_end;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500758 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500759 lock->fl.fl_flags &= ~FL_SLEEP;
NeilBrown2ec197d2014-02-07 17:10:26 +1100760 lock->fl.fl_start = fl_start;
761 lock->fl.fl_end = fl_end;
Trond Myklebust09c79382006-03-20 13:44:38 -0500762
Andy Adamson5de0e502006-03-20 13:44:25 -0500763 switch (error) {
764 case 0:
765 break;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700766 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500767 dprintk("lockd: lock still blocked error %d\n", error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 nlmsvc_insert_block(block, NLM_NEVER);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500769 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500770 return;
Andy Adamson5de0e502006-03-20 13:44:25 -0500771 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700773 -error, __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 nlmsvc_insert_block(block, 10 * HZ);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500775 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500776 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 }
778
779callback:
780 /* Lock was granted by VFS. */
781 dprintk("lockd: GRANTing blocked lock.\n");
782 block->b_granted = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783
Jeff Layton97065012008-02-06 11:34:12 -0500784 /* keep block on the list, but don't reattempt until the RPC
785 * completes or the submission fails
786 */
787 nlmsvc_insert_block(block, NLM_NEVER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788
Jeff Layton97065012008-02-06 11:34:12 -0500789 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
790 * will queue up a new one if this one times out
791 */
792 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
793 &nlmsvc_grant_ops);
794
795 /* RPC submission failed, wait a bit and retry */
796 if (error < 0)
797 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798}
799
800/*
801 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
802 * RPC call has succeeded or timed out.
803 * Like all RPC callbacks, it is invoked by the rpciod process, so it
804 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
805 * chain once more in order to have it removed by lockd itself (which can
806 * then sleep on the file semaphore without disrupting e.g. the nfs client).
807 */
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100808static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809{
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100810 struct nlm_rqst *call = data;
Trond Myklebust92737232006-03-20 13:44:45 -0500811 struct nlm_block *block = call->a_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 unsigned long timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813
814 dprintk("lockd: GRANT_MSG RPC callback\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815
Bryan Schumakerf904be92010-09-21 16:38:12 -0400816 spin_lock(&nlm_blocked_lock);
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500817 /* if the block is not on a list at this point then it has
818 * been invalidated. Don't try to requeue it.
819 *
820 * FIXME: it's possible that the block is removed from the list
821 * after this check but before the nlmsvc_insert_block. In that
822 * case it will be added back. Perhaps we need better locking
823 * for nlm_blocked?
824 */
825 if (list_empty(&block->b_list))
Trond Myklebusta86dc492008-06-11 13:37:09 -0400826 goto out;
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500827
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 /* Technically, we should down the file semaphore here. Since we
829 * move the block towards the head of the queue only, no harm
830 * can be done, though. */
831 if (task->tk_status < 0) {
832 /* RPC error: Re-insert for retransmission */
833 timeout = 10 * HZ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 } else {
835 /* Call was successful, now wait for client callback */
836 timeout = 60 * HZ;
837 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400838 nlmsvc_insert_block_locked(block, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 svc_wake_up(block->b_daemon);
Trond Myklebusta86dc492008-06-11 13:37:09 -0400840out:
Bryan Schumakerf904be92010-09-21 16:38:12 -0400841 spin_unlock(&nlm_blocked_lock);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500842}
843
Bryan Schumakerf904be92010-09-21 16:38:12 -0400844/*
845 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
846 * .rpc_release rpc_call_op
847 */
Adrian Bunkec535ce2006-04-18 13:21:50 -0400848static void nlmsvc_grant_release(void *data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500849{
Trond Myklebust6041b792006-03-20 13:44:45 -0500850 struct nlm_rqst *call = data;
Trond Myklebust6041b792006-03-20 13:44:45 -0500851 nlmsvc_release_block(call->a_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852}
853
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100854static const struct rpc_call_ops nlmsvc_grant_ops = {
855 .rpc_call_done = nlmsvc_grant_callback,
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500856 .rpc_release = nlmsvc_grant_release,
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100857};
858
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859/*
860 * We received a GRANT_RES callback. Try to find the corresponding
861 * block.
862 */
863void
Al Viroe8c5c042006-12-13 00:35:03 -0800864nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865{
866 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867
Olaf Kirch39be4502006-10-04 02:16:03 -0700868 dprintk("grant_reply: looking for cookie %x, s=%d \n",
869 *(unsigned int *)(cookie->data), status);
870 if (!(block = nlmsvc_find_block(cookie)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872
J. Bruce Fieldsf2321422006-01-03 09:55:42 +0100873 if (block) {
Al Viroe8c5c042006-12-13 00:35:03 -0800874 if (status == nlm_lck_denied_grace_period) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 /* Try again in a couple of seconds */
876 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 } else {
878 /* Lock is now held by client, or has been rejected.
879 * In both cases, the block should be removed. */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500880 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 }
882 }
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500883 nlmsvc_release_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884}
885
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500886/* Helper function to handle retry of a deferred block.
887 * If it is a blocking lock, call grant_blocked.
888 * For a non-blocking lock or test lock, revisit the request.
889 */
890static void
891retry_deferred_block(struct nlm_block *block)
892{
893 if (!(block->b_flags & B_GOT_CALLBACK))
894 block->b_flags |= B_TIMED_OUT;
895 nlmsvc_insert_block(block, NLM_TIMEOUT);
896 dprintk("revisit block %p flags %d\n", block, block->b_flags);
897 if (block->b_deferred_req) {
898 block->b_deferred_req->revisit(block->b_deferred_req, 0);
899 block->b_deferred_req = NULL;
900 }
901}
902
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903/*
904 * Retry all blocked locks that have been notified. This is where lockd
905 * picks up locks that can be granted, or grant notifications that must
906 * be retransmitted.
907 */
908unsigned long
909nlmsvc_retry_blocked(void)
910{
Olaf Kirch68a2d762006-10-04 02:15:57 -0700911 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
912 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913
David Jeffery1c327d92013-07-10 13:19:50 -0400914 spin_lock(&nlm_blocked_lock);
Jeff Laytond751a7c2008-02-07 16:34:55 -0500915 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
Olaf Kirch68a2d762006-10-04 02:15:57 -0700916 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
917
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 if (block->b_when == NLM_NEVER)
919 break;
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400920 if (time_after(block->b_when, jiffies)) {
Olaf Kirch68a2d762006-10-04 02:15:57 -0700921 timeout = block->b_when - jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 break;
Olaf Kirch68a2d762006-10-04 02:15:57 -0700923 }
David Jeffery1c327d92013-07-10 13:19:50 -0400924 spin_unlock(&nlm_blocked_lock);
Olaf Kirch68a2d762006-10-04 02:15:57 -0700925
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);
David Jeffery1c327d92013-07-10 13:19:50 -0400934 spin_lock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 }
David Jeffery1c327d92013-07-10 13:19:50 -0400936 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937
Olaf Kirch68a2d762006-10-04 02:15:57 -0700938 return timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939}