blob: e703318c41dface91c09b100a3c88bacd63f6751 [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 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50/*
51 * The list of blocked locks to retry
52 */
Olaf Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 02:15:57 -0700129static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130nlmsvc_remove_block(struct nlm_block *block)
131{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700132 if (!list_empty(&block->b_list)) {
Bryan Schumakerf904be92010-09-21 16:38:12 -0400133 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700134 list_del_init(&block->b_list);
Bryan Schumakerf904be92010-09-21 16:38:12 -0400135 spin_unlock(&nlm_blocked_lock);
Olaf Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 02:15:57 -0700188 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 }
190
Olaf Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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 Kirch68a2d76c2006-10-04 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;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500248 block->b_fl = NULL;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500249 file->f_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250
251 /* Add to file's list of blocks */
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700252 list_add(&block->b_flist, &file->f_blocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254 /* Set up RPC arguments for callback */
Trond Myklebust92737232006-03-20 13:44:45 -0500255 block->b_call = call;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 call->a_flags = RPC_TASK_ASYNC;
Trond Myklebust92737232006-03-20 13:44:45 -0500257 call->a_block = block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 return block;
260
261failed_free:
262 kfree(block);
263failed:
Chuck Lever7db836d2010-12-14 15:05:42 +0000264 nlmsvc_release_call(call);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 return NULL;
266}
267
268/*
J. Bruce Fields3c61eec2008-04-07 13:05:27 -0400269 * Delete a block.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 * It is the caller's responsibility to check whether the file
271 * can be closed hereafter.
272 */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500273static int nlmsvc_unlink_block(struct nlm_block *block)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274{
Trond Myklebust09c79382006-03-20 13:44:38 -0500275 int status;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500276 dprintk("lockd: unlinking block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
278 /* Remove block from list */
Trond Myklebust92737232006-03-20 13:44:45 -0500279 status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 nlmsvc_remove_block(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500281 return status;
282}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500284static void nlmsvc_free_block(struct kref *kref)
285{
286 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
287 struct nlm_file *file = block->b_file;
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500288
289 dprintk("lockd: freeing block %p...\n", block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
291 /* Remove block from file's list of blocks */
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700292 list_del_init(&block->b_flist);
Neil Brown89e63ef2006-10-04 02:16:06 -0700293 mutex_unlock(&file->f_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
Trond Myklebust92737232006-03-20 13:44:45 -0500295 nlmsvc_freegrantargs(block->b_call);
Chuck Lever7db836d2010-12-14 15:05:42 +0000296 nlmsvc_release_call(block->b_call);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500297 nlm_release_file(block->b_file);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500298 kfree(block->b_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 kfree(block);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500300}
301
302static void nlmsvc_release_block(struct nlm_block *block)
303{
304 if (block != NULL)
Al Viroc5aa1e52012-08-29 09:00:01 -0400305 kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306}
307
Olaf Kirchf2af7932006-10-04 02:15:59 -0700308/*
309 * Loop over all blocks and delete blocks held by
310 * a matching host.
311 */
312void nlmsvc_traverse_blocks(struct nlm_host *host,
313 struct nlm_file *file,
314 nlm_host_match_fn_t match)
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500315{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700316 struct nlm_block *block, *next;
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500317
318restart:
Neil Brown89e63ef2006-10-04 02:16:06 -0700319 mutex_lock(&file->f_mutex);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700320 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
Olaf Kirchf2af7932006-10-04 02:15:59 -0700321 if (!match(block->b_host, host))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500322 continue;
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700323 /* Do not destroy blocks that are not on
324 * the global retry list - why? */
325 if (list_empty(&block->b_list))
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500326 continue;
327 kref_get(&block->b_count);
Neil Brown89e63ef2006-10-04 02:16:06 -0700328 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500329 nlmsvc_unlink_block(block);
330 nlmsvc_release_block(block);
331 goto restart;
332 }
Neil Brown89e63ef2006-10-04 02:16:06 -0700333 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500334}
335
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336/*
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500337 * Initialize arguments for GRANTED call. The nlm_rqst structure
338 * has been cleared already.
339 */
340static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
341{
342 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
343 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
Serge E. Hallyne9ff3992006-10-02 02:18:11 -0700344 call->a_args.lock.caller = utsname()->nodename;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500345 call->a_args.lock.oh.len = lock->oh.len;
346
347 /* set default data area */
348 call->a_args.lock.oh.data = call->a_owner;
349 call->a_args.lock.svid = lock->fl.fl_pid;
350
351 if (lock->oh.len > NLMCLNT_OHSIZE) {
352 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
Trond Myklebust92737232006-03-20 13:44:45 -0500353 if (!data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500354 return 0;
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500355 call->a_args.lock.oh.data = (u8 *) data;
356 }
357
358 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
359 return 1;
360}
361
362static void nlmsvc_freegrantargs(struct nlm_rqst *call)
363{
Trond Myklebust92737232006-03-20 13:44:45 -0500364 if (call->a_args.lock.oh.data != call->a_owner)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500365 kfree(call->a_args.lock.oh.data);
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500366
367 locks_release_private(&call->a_args.lock.fl);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500368}
369
370/*
Marc Eshel2b36f412006-11-28 16:26:47 -0500371 * Deferred lock request handling for non-blocking lock
372 */
Al Viroca5c8cd2007-07-26 17:33:49 +0100373static __be32
Marc Eshel2b36f412006-11-28 16:26:47 -0500374nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
375{
Al Viroca5c8cd2007-07-26 17:33:49 +0100376 __be32 status = nlm_lck_denied_nolocks;
Marc Eshel2b36f412006-11-28 16:26:47 -0500377
378 block->b_flags |= B_QUEUED;
379
380 nlmsvc_insert_block(block, NLM_TIMEOUT);
381
382 block->b_cache_req = &rqstp->rq_chandle;
383 if (rqstp->rq_chandle.defer) {
384 block->b_deferred_req =
385 rqstp->rq_chandle.defer(block->b_cache_req);
386 if (block->b_deferred_req != NULL)
387 status = nlm_drop_reply;
388 }
389 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
Al Viroca5c8cd2007-07-26 17:33:49 +0100390 block, block->b_flags, ntohl(status));
Marc Eshel2b36f412006-11-28 16:26:47 -0500391
392 return status;
393}
394
395/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 * Attempt to establish a lock, and if it can't be granted, block it
397 * if required.
398 */
Al Viro52921e02006-10-19 23:28:46 -0700399__be32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton6cde4de2008-07-15 14:26:17 -0400401 struct nlm_host *host, struct nlm_lock *lock, int wait,
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500402 struct nlm_cookie *cookie, int reclaim)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403{
Marc Eshelf8120482006-12-05 23:48:10 -0500404 struct nlm_block *block = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 int error;
Al Viro52921e02006-10-19 23:28:46 -0700406 __be32 ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500409 file_inode(file->f_file)->i_sb->s_id,
410 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 lock->fl.fl_type, lock->fl.fl_pid,
412 (long long)lock->fl.fl_start,
413 (long long)lock->fl.fl_end,
414 wait);
415
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 /* Lock file against concurrent access */
Neil Brown89e63ef2006-10-04 02:16:06 -0700417 mutex_lock(&file->f_mutex);
Marc Eshelf8120482006-12-05 23:48:10 -0500418 /* Get existing block (in case client is busy-waiting)
419 * or create new block
420 */
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500421 block = nlmsvc_lookup_block(file, lock);
Trond Myklebust09c79382006-03-20 13:44:38 -0500422 if (block == NULL) {
J. Bruce Fields560de0e2008-07-15 15:05:45 -0400423 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshelf8120482006-12-05 23:48:10 -0500424 ret = nlm_lck_denied_nolocks;
425 if (block == NULL)
426 goto out;
Trond Myklebust92737232006-03-20 13:44:45 -0500427 lock = &block->b_call->a_args.lock;
Marc Eshelf8120482006-12-05 23:48:10 -0500428 } else
429 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
Marc Eshel1a8322b2006-11-28 16:27:06 -0500431 if (block->b_flags & B_QUEUED) {
432 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
433 block, block->b_flags);
434 if (block->b_granted) {
435 nlmsvc_unlink_block(block);
436 ret = nlm_granted;
437 goto out;
438 }
439 if (block->b_flags & B_TIMED_OUT) {
440 nlmsvc_unlink_block(block);
441 ret = nlm_lck_denied;
442 goto out;
443 }
444 ret = nlm_drop_reply;
445 goto out;
446 }
447
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400448 if (locks_in_grace(SVC_NET(rqstp)) && !reclaim) {
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500449 ret = nlm_lck_denied_grace_period;
450 goto out;
451 }
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400452 if (reclaim && !locks_in_grace(SVC_NET(rqstp))) {
J. Bruce Fieldsd22b1cf2008-02-06 15:05:12 -0500453 ret = nlm_lck_denied_grace_period;
454 goto out;
455 }
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500456
Marc Eshel1a8322b2006-11-28 16:27:06 -0500457 if (!wait)
458 lock->fl.fl_flags &= ~FL_SLEEP;
459 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500460 lock->fl.fl_flags &= ~FL_SLEEP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
Marc Eshel1a8322b2006-11-28 16:27:06 -0500462 dprintk("lockd: vfs_lock_file returned %d\n", error);
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400463 switch (error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 case 0:
Andy Adamson15dadef2006-03-20 13:44:24 -0500465 ret = nlm_granted;
466 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500467 case -EAGAIN:
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500468 /*
469 * If this is a blocking request for an
470 * already pending lock request then we need
471 * to put it back on lockd's block list
472 */
473 if (wait)
474 break;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500475 ret = nlm_lck_denied;
Miklos Szeredie33d1ea2009-02-09 12:30:43 -0500476 goto out;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700477 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500478 if (wait)
479 break;
480 /* Filesystem lock operation is in progress
481 Add it to the queue waiting for callback */
482 ret = nlmsvc_defer_lock_rqst(rqstp, block);
483 goto out;
Trond Myklebust09c79382006-03-20 13:44:38 -0500484 case -EDEADLK:
Andy Adamson15dadef2006-03-20 13:44:24 -0500485 ret = nlm_deadlock;
486 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 default: /* includes ENOLCK */
Andy Adamson15dadef2006-03-20 13:44:24 -0500488 ret = nlm_lck_denied_nolocks;
489 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 }
491
Trond Myklebust09c79382006-03-20 13:44:38 -0500492 ret = nlm_lck_blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 /* Append to list of blocked */
Marc Eshelf8120482006-12-05 23:48:10 -0500495 nlmsvc_insert_block(block, NLM_NEVER);
Andy Adamson15dadef2006-03-20 13:44:24 -0500496out:
Neil Brown89e63ef2006-10-04 02:16:06 -0700497 mutex_unlock(&file->f_mutex);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500498 nlmsvc_release_block(block);
Andy Adamson15dadef2006-03-20 13:44:24 -0500499 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
500 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501}
502
503/*
504 * Test for presence of a conflicting lock.
505 */
Al Viro52921e02006-10-19 23:28:46 -0700506__be32
Marc Eshel85f3f1b32006-11-28 16:27:06 -0500507nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
Jeff Layton8f920d52008-07-15 14:06:48 -0400508 struct nlm_host *host, struct nlm_lock *lock,
509 struct nlm_lock *conflock, struct nlm_cookie *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510{
Marc Eshel5ea0d752006-11-28 16:27:06 -0500511 struct nlm_block *block = NULL;
512 int error;
513 __be32 ret;
514
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500516 file_inode(file->f_file)->i_sb->s_id,
517 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 lock->fl.fl_type,
519 (long long)lock->fl.fl_start,
520 (long long)lock->fl.fl_end);
521
Marc Eshel5ea0d752006-11-28 16:27:06 -0500522 /* Get existing block (in case client is busy-waiting) */
523 block = nlmsvc_lookup_block(file, lock);
524
525 if (block == NULL) {
526 struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
527
528 if (conf == NULL)
529 return nlm_granted;
Trond Myklebust255129d2007-09-25 15:55:03 -0400530 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500531 if (block == NULL) {
532 kfree(conf);
533 return nlm_granted;
534 }
535 block->b_fl = conf;
536 }
537 if (block->b_flags & B_QUEUED) {
538 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
539 block, block->b_flags, block->b_fl);
540 if (block->b_flags & B_TIMED_OUT) {
541 nlmsvc_unlink_block(block);
Oleg Drokin29dbf542007-11-29 14:02:21 -0500542 ret = nlm_lck_denied;
543 goto out;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500544 }
545 if (block->b_flags & B_GOT_CALLBACK) {
Oleg Drokin54ca95e2008-01-11 21:57:35 -0500546 nlmsvc_unlink_block(block);
Marc Eshel5ea0d752006-11-28 16:27:06 -0500547 if (block->b_fl != NULL
548 && block->b_fl->fl_type != F_UNLCK) {
549 lock->fl = *block->b_fl;
550 goto conf_lock;
Oleg Drokin29dbf542007-11-29 14:02:21 -0500551 } else {
Oleg Drokin29dbf542007-11-29 14:02:21 -0500552 ret = nlm_granted;
553 goto out;
Marc Eshel5ea0d752006-11-28 16:27:06 -0500554 }
555 }
Oleg Drokin29dbf542007-11-29 14:02:21 -0500556 ret = nlm_drop_reply;
557 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 }
559
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400560 if (locks_in_grace(SVC_NET(rqstp))) {
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500561 ret = nlm_lck_denied_grace_period;
562 goto out;
563 }
Marc Eshel5ea0d752006-11-28 16:27:06 -0500564 error = vfs_test_lock(file->f_file, &lock->fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -0700565 if (error == FILE_LOCK_DEFERRED) {
Oleg Drokin29dbf542007-11-29 14:02:21 -0500566 ret = nlmsvc_defer_lock_rqst(rqstp, block);
567 goto out;
568 }
Marc Eshel5ea0d752006-11-28 16:27:06 -0500569 if (error) {
570 ret = nlm_lck_denied_nolocks;
571 goto out;
572 }
573 if (lock->fl.fl_type == F_UNLCK) {
574 ret = nlm_granted;
575 goto out;
576 }
577
578conf_lock:
579 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
580 lock->fl.fl_type, (long long)lock->fl.fl_start,
581 (long long)lock->fl.fl_end);
582 conflock->caller = "somehost"; /* FIXME */
583 conflock->len = strlen(conflock->caller);
584 conflock->oh.len = 0; /* don't return OH info */
585 conflock->svid = lock->fl.fl_pid;
586 conflock->fl.fl_type = lock->fl.fl_type;
587 conflock->fl.fl_start = lock->fl.fl_start;
588 conflock->fl.fl_end = lock->fl.fl_end;
589 ret = nlm_lck_denied;
590out:
591 if (block)
592 nlmsvc_release_block(block);
593 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594}
595
596/*
597 * Remove a lock.
598 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
599 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
600 * afterwards. In this case the block will still be there, and hence
601 * must be removed.
602 */
Al Viro52921e02006-10-19 23:28:46 -0700603__be32
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400604nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605{
606 int error;
607
608 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500609 file_inode(file->f_file)->i_sb->s_id,
610 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 lock->fl.fl_pid,
612 (long long)lock->fl.fl_start,
613 (long long)lock->fl.fl_end);
614
615 /* First, cancel any lock that might be there */
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400616 nlmsvc_cancel_blocked(net, file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617
618 lock->fl.fl_type = F_UNLCK;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500619 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620
621 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
622}
623
624/*
625 * Cancel a previously blocked request.
626 *
627 * A cancel request always overrides any grant that may currently
628 * be in progress.
629 * The calling procedure must check whether the file can be closed.
630 */
Al Viro52921e02006-10-19 23:28:46 -0700631__be32
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400632nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633{
634 struct nlm_block *block;
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100635 int status = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636
637 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
Al Viro496ad9a2013-01-23 17:07:38 -0500638 file_inode(file->f_file)->i_sb->s_id,
639 file_inode(file->f_file)->i_ino,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 lock->fl.fl_pid,
641 (long long)lock->fl.fl_start,
642 (long long)lock->fl.fl_end);
643
Stanislav Kinsbursky5ccb0062012-07-25 16:57:22 +0400644 if (locks_in_grace(net))
J. Bruce Fieldsb2b50282008-02-06 13:59:23 -0500645 return nlm_lck_denied_grace_period;
646
Neil Brown89e63ef2006-10-04 02:16:06 -0700647 mutex_lock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500648 block = nlmsvc_lookup_block(file, lock);
Neil Brown89e63ef2006-10-04 02:16:06 -0700649 mutex_unlock(&file->f_mutex);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500650 if (block != NULL) {
Marc Eshel1a8322b2006-11-28 16:27:06 -0500651 vfs_cancel_lock(block->b_file->f_file,
652 &block->b_call->a_args.lock.fl);
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500653 status = nlmsvc_unlink_block(block);
654 nlmsvc_release_block(block);
655 }
J. Bruce Fields64a318e2006-01-03 09:55:46 +0100656 return status ? nlm_lck_denied : nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657}
658
659/*
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500660 * This is a callback from the filesystem for VFS file lock requests.
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400661 * It will be used if lm_grant is defined and the filesystem can not
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500662 * respond to the request immediately.
663 * For GETLK request it will copy the reply to the nlm_block.
664 * For SETLK or SETLKW request it will get the local posix lock.
665 * In all cases it will move the block to the head of nlm_blocked q where
666 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
667 * deferred rpc for GETLK and SETLK.
668 */
669static void
670nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf,
671 int result)
672{
673 block->b_flags |= B_GOT_CALLBACK;
674 if (result == 0)
675 block->b_granted = 1;
676 else
677 block->b_flags |= B_TIMED_OUT;
678 if (conf) {
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500679 if (block->b_fl)
J. Bruce Fields1a747ee2008-04-24 10:08:22 -0400680 __locks_copy_lock(block->b_fl, conf);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500681 }
682}
683
684static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
685 int result)
686{
687 struct nlm_block *block;
688 int rc = -ENOENT;
689
Bryan Schumakerf904be92010-09-21 16:38:12 -0400690 spin_lock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500691 list_for_each_entry(block, &nlm_blocked, b_list) {
692 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
693 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
694 block, block->b_flags);
695 if (block->b_flags & B_QUEUED) {
696 if (block->b_flags & B_TIMED_OUT) {
697 rc = -ENOLCK;
698 break;
699 }
700 nlmsvc_update_deferred_block(block, conf, result);
701 } else if (result == 0)
702 block->b_granted = 1;
703
Bryan Schumakerf904be92010-09-21 16:38:12 -0400704 nlmsvc_insert_block_locked(block, 0);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500705 svc_wake_up(block->b_daemon);
706 rc = 0;
707 break;
708 }
709 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400710 spin_unlock(&nlm_blocked_lock);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500711 if (rc == -ENOENT)
712 printk(KERN_WARNING "lockd: grant for unknown block\n");
713 return rc;
714}
715
716/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 * Unblock a blocked lock request. This is a callback invoked from the
718 * VFS layer when a lock on which we blocked is removed.
719 *
720 * This function doesn't grant the blocked lock instantly, but rather moves
721 * the block to the head of nlm_blocked where it can be picked up by lockd.
722 */
723static void
724nlmsvc_notify_blocked(struct file_lock *fl)
725{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700726 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727
728 dprintk("lockd: VFS unblock notification for block %p\n", fl);
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400729 spin_lock(&nlm_blocked_lock);
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700730 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust92737232006-03-20 13:44:45 -0500731 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400732 nlmsvc_insert_block_locked(block, 0);
733 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 svc_wake_up(block->b_daemon);
735 return;
736 }
737 }
J. Bruce Fieldsa282a1f2010-10-26 18:25:30 -0400738 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 printk(KERN_WARNING "lockd: notification for unknown block!\n");
740}
741
742static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
743{
744 return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
745}
746
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700747const struct lock_manager_operations nlmsvc_lock_operations = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400748 .lm_compare_owner = nlmsvc_same_owner,
749 .lm_notify = nlmsvc_notify_blocked,
750 .lm_grant = nlmsvc_grant_deferred,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751};
752
753/*
754 * Try to claim a lock that was previously blocked.
755 *
756 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
757 * RPC thread when notifying the client. This seems like overkill...
758 * Here's why:
759 * - we don't want to use a synchronous RPC thread, otherwise
760 * we might find ourselves hanging on a dead portmapper.
761 * - Some lockd implementations (e.g. HP) don't react to
762 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
763 */
764static void
765nlmsvc_grant_blocked(struct nlm_block *block)
766{
767 struct nlm_file *file = block->b_file;
Trond Myklebust92737232006-03-20 13:44:45 -0500768 struct nlm_lock *lock = &block->b_call->a_args.lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 int error;
770
771 dprintk("lockd: grant blocked lock %p\n", block);
772
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500773 kref_get(&block->b_count);
774
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 /* Unlink block request from list */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500776 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778 /* If b_granted is true this means we've been here before.
779 * Just retry the grant callback, possibly refreshing the RPC
780 * binding */
781 if (block->b_granted) {
782 nlm_rebind_host(block->b_host);
783 goto callback;
784 }
785
786 /* Try the lock operation again */
Trond Myklebust09c79382006-03-20 13:44:38 -0500787 lock->fl.fl_flags |= FL_SLEEP;
Marc Eshel1a8322b2006-11-28 16:27:06 -0500788 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
Trond Myklebust09c79382006-03-20 13:44:38 -0500789 lock->fl.fl_flags &= ~FL_SLEEP;
790
Andy Adamson5de0e502006-03-20 13:44:25 -0500791 switch (error) {
792 case 0:
793 break;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700794 case FILE_LOCK_DEFERRED:
Marc Eshel1a8322b2006-11-28 16:27:06 -0500795 dprintk("lockd: lock still blocked error %d\n", error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 nlmsvc_insert_block(block, NLM_NEVER);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500797 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500798 return;
Andy Adamson5de0e502006-03-20 13:44:25 -0500799 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700801 -error, __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 nlmsvc_insert_block(block, 10 * HZ);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500803 nlmsvc_release_block(block);
Trond Myklebustd9f6eb72006-03-20 13:44:47 -0500804 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 }
806
807callback:
808 /* Lock was granted by VFS. */
809 dprintk("lockd: GRANTing blocked lock.\n");
810 block->b_granted = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
Jeff Layton97065012008-02-06 11:34:12 -0500812 /* keep block on the list, but don't reattempt until the RPC
813 * completes or the submission fails
814 */
815 nlmsvc_insert_block(block, NLM_NEVER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
Jeff Layton97065012008-02-06 11:34:12 -0500817 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
818 * will queue up a new one if this one times out
819 */
820 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
821 &nlmsvc_grant_ops);
822
823 /* RPC submission failed, wait a bit and retry */
824 if (error < 0)
825 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826}
827
828/*
829 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
830 * RPC call has succeeded or timed out.
831 * Like all RPC callbacks, it is invoked by the rpciod process, so it
832 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
833 * chain once more in order to have it removed by lockd itself (which can
834 * then sleep on the file semaphore without disrupting e.g. the nfs client).
835 */
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100836static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837{
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100838 struct nlm_rqst *call = data;
Trond Myklebust92737232006-03-20 13:44:45 -0500839 struct nlm_block *block = call->a_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 unsigned long timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841
842 dprintk("lockd: GRANT_MSG RPC callback\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843
Bryan Schumakerf904be92010-09-21 16:38:12 -0400844 spin_lock(&nlm_blocked_lock);
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500845 /* if the block is not on a list at this point then it has
846 * been invalidated. Don't try to requeue it.
847 *
848 * FIXME: it's possible that the block is removed from the list
849 * after this check but before the nlmsvc_insert_block. In that
850 * case it will be added back. Perhaps we need better locking
851 * for nlm_blocked?
852 */
853 if (list_empty(&block->b_list))
Trond Myklebusta86dc492008-06-11 13:37:09 -0400854 goto out;
Jeff Laytonc64e80d2008-02-06 11:34:13 -0500855
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 /* Technically, we should down the file semaphore here. Since we
857 * move the block towards the head of the queue only, no harm
858 * can be done, though. */
859 if (task->tk_status < 0) {
860 /* RPC error: Re-insert for retransmission */
861 timeout = 10 * HZ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 } else {
863 /* Call was successful, now wait for client callback */
864 timeout = 60 * HZ;
865 }
Bryan Schumakerf904be92010-09-21 16:38:12 -0400866 nlmsvc_insert_block_locked(block, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 svc_wake_up(block->b_daemon);
Trond Myklebusta86dc492008-06-11 13:37:09 -0400868out:
Bryan Schumakerf904be92010-09-21 16:38:12 -0400869 spin_unlock(&nlm_blocked_lock);
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500870}
871
Bryan Schumakerf904be92010-09-21 16:38:12 -0400872/*
873 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
874 * .rpc_release rpc_call_op
875 */
Adrian Bunkec535ce152006-04-18 13:21:50 -0400876static void nlmsvc_grant_release(void *data)
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500877{
Trond Myklebust6041b792006-03-20 13:44:45 -0500878 struct nlm_rqst *call = data;
Trond Myklebust6041b792006-03-20 13:44:45 -0500879 nlmsvc_release_block(call->a_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880}
881
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100882static const struct rpc_call_ops nlmsvc_grant_ops = {
883 .rpc_call_done = nlmsvc_grant_callback,
Trond Myklebust5e1abf82006-03-20 13:44:39 -0500884 .rpc_release = nlmsvc_grant_release,
Trond Myklebust963d8fe2006-01-03 09:55:04 +0100885};
886
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887/*
888 * We received a GRANT_RES callback. Try to find the corresponding
889 * block.
890 */
891void
Al Viroe8c5c042006-12-13 00:35:03 -0800892nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893{
894 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895
Olaf Kirch39be4502006-10-04 02:16:03 -0700896 dprintk("grant_reply: looking for cookie %x, s=%d \n",
897 *(unsigned int *)(cookie->data), status);
898 if (!(block = nlmsvc_find_block(cookie)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900
J. Bruce Fieldsf2321422006-01-03 09:55:42 +0100901 if (block) {
Al Viroe8c5c042006-12-13 00:35:03 -0800902 if (status == nlm_lck_denied_grace_period) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 /* Try again in a couple of seconds */
904 nlmsvc_insert_block(block, 10 * HZ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 } else {
906 /* Lock is now held by client, or has been rejected.
907 * In both cases, the block should be removed. */
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500908 nlmsvc_unlink_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 }
910 }
Trond Myklebust6849c0c2006-03-20 13:44:39 -0500911 nlmsvc_release_block(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912}
913
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500914/* Helper function to handle retry of a deferred block.
915 * If it is a blocking lock, call grant_blocked.
916 * For a non-blocking lock or test lock, revisit the request.
917 */
918static void
919retry_deferred_block(struct nlm_block *block)
920{
921 if (!(block->b_flags & B_GOT_CALLBACK))
922 block->b_flags |= B_TIMED_OUT;
923 nlmsvc_insert_block(block, NLM_TIMEOUT);
924 dprintk("revisit block %p flags %d\n", block, block->b_flags);
925 if (block->b_deferred_req) {
926 block->b_deferred_req->revisit(block->b_deferred_req, 0);
927 block->b_deferred_req = NULL;
928 }
929}
930
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931/*
932 * Retry all blocked locks that have been notified. This is where lockd
933 * picks up locks that can be granted, or grant notifications that must
934 * be retransmitted.
935 */
936unsigned long
937nlmsvc_retry_blocked(void)
938{
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700939 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
940 struct nlm_block *block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941
Jeff Laytond751a7c2008-02-07 16:34:55 -0500942 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700943 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
944
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 if (block->b_when == NLM_NEVER)
946 break;
J. Bruce Fields6d7bbbb2008-07-15 14:38:32 -0400947 if (time_after(block->b_when, jiffies)) {
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700948 timeout = block->b_when - jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 break;
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700950 }
951
J. Bruce Fieldsf3d43c72006-08-03 15:07:47 -0400952 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
953 block, block->b_when);
Marc Eshel0e4ac9d2006-11-28 16:26:51 -0500954 if (block->b_flags & B_QUEUED) {
955 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
956 block, block->b_granted, block->b_flags);
957 retry_deferred_block(block);
958 } else
959 nlmsvc_grant_blocked(block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 }
961
Olaf Kirch68a2d76c2006-10-04 02:15:57 -0700962 return timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963}