1 |
3 |
xianfeng |
/*
|
2 |
|
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* linux/fs/lockd/svclock.c
|
3 |
|
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*
|
4 |
|
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* Handling of server-side locks, mostly of the blocked variety.
|
5 |
|
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* This is the ugliest part of lockd because we tread on very thin ice.
|
6 |
|
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* GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
|
7 |
|
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* IMNSHO introducing the grant callback into the NLM protocol was one
|
8 |
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* of the worst ideas Sun ever had. Except maybe for the idea of doing
|
9 |
|
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* NFS file locking at all.
|
10 |
|
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*
|
11 |
|
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* I'm trying hard to avoid race conditions by protecting most accesses
|
12 |
|
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* to a file's list of blocked locks through a semaphore. The global
|
13 |
|
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* list of blocked locks is not protected in this fashion however.
|
14 |
|
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* 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 |
|
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* process might be traversing it*. This should not be a problem in
|
17 |
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* practice, because this will only cause functions traversing the list
|
18 |
|
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* to visit some blocks twice.
|
19 |
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*
|
20 |
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
|
21 |
|
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*/
|
22 |
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|
23 |
|
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#include <linux/types.h>
|
24 |
|
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#include <linux/errno.h>
|
25 |
|
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#include <linux/kernel.h>
|
26 |
|
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#include <linux/sched.h>
|
27 |
|
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#include <linux/smp_lock.h>
|
28 |
|
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#include <linux/sunrpc/clnt.h>
|
29 |
|
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#include <linux/sunrpc/svc.h>
|
30 |
|
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#include <linux/lockd/nlm.h>
|
31 |
|
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#include <linux/lockd/lockd.h>
|
32 |
|
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|
33 |
|
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#define NLMDBG_FACILITY NLMDBG_SVCLOCK
|
34 |
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|
35 |
|
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#ifdef CONFIG_LOCKD_V4
|
36 |
|
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#define nlm_deadlock nlm4_deadlock
|
37 |
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#else
|
38 |
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#define nlm_deadlock nlm_lck_denied
|
39 |
|
|
#endif
|
40 |
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|
41 |
|
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static void nlmsvc_release_block(struct nlm_block *block);
|
42 |
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static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
|
43 |
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|
static void nlmsvc_remove_block(struct nlm_block *block);
|
44 |
|
|
|
45 |
|
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static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
|
46 |
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static void nlmsvc_freegrantargs(struct nlm_rqst *call);
|
47 |
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static const struct rpc_call_ops nlmsvc_grant_ops;
|
48 |
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|
49 |
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/*
|
50 |
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* The list of blocked locks to retry
|
51 |
|
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*/
|
52 |
|
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static LIST_HEAD(nlm_blocked);
|
53 |
|
|
|
54 |
|
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/*
|
55 |
|
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* Insert a blocked lock into the global list
|
56 |
|
|
*/
|
57 |
|
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static void
|
58 |
|
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nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
|
59 |
|
|
{
|
60 |
|
|
struct nlm_block *b;
|
61 |
|
|
struct list_head *pos;
|
62 |
|
|
|
63 |
|
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dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
|
64 |
|
|
if (list_empty(&block->b_list)) {
|
65 |
|
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kref_get(&block->b_count);
|
66 |
|
|
} else {
|
67 |
|
|
list_del_init(&block->b_list);
|
68 |
|
|
}
|
69 |
|
|
|
70 |
|
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pos = &nlm_blocked;
|
71 |
|
|
if (when != NLM_NEVER) {
|
72 |
|
|
if ((when += jiffies) == NLM_NEVER)
|
73 |
|
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when ++;
|
74 |
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list_for_each(pos, &nlm_blocked) {
|
75 |
|
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b = list_entry(pos, struct nlm_block, b_list);
|
76 |
|
|
if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
|
77 |
|
|
break;
|
78 |
|
|
}
|
79 |
|
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/* On normal exit from the loop, pos == &nlm_blocked,
|
80 |
|
|
* so we will be adding to the end of the list - good
|
81 |
|
|
*/
|
82 |
|
|
}
|
83 |
|
|
|
84 |
|
|
list_add_tail(&block->b_list, pos);
|
85 |
|
|
block->b_when = when;
|
86 |
|
|
}
|
87 |
|
|
|
88 |
|
|
/*
|
89 |
|
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* Remove a block from the global list
|
90 |
|
|
*/
|
91 |
|
|
static inline void
|
92 |
|
|
nlmsvc_remove_block(struct nlm_block *block)
|
93 |
|
|
{
|
94 |
|
|
if (!list_empty(&block->b_list)) {
|
95 |
|
|
list_del_init(&block->b_list);
|
96 |
|
|
nlmsvc_release_block(block);
|
97 |
|
|
}
|
98 |
|
|
}
|
99 |
|
|
|
100 |
|
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/*
|
101 |
|
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* Find a block for a given lock
|
102 |
|
|
*/
|
103 |
|
|
static struct nlm_block *
|
104 |
|
|
nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
|
105 |
|
|
{
|
106 |
|
|
struct nlm_block *block;
|
107 |
|
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struct file_lock *fl;
|
108 |
|
|
|
109 |
|
|
dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
|
110 |
|
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file, lock->fl.fl_pid,
|
111 |
|
|
(long long)lock->fl.fl_start,
|
112 |
|
|
(long long)lock->fl.fl_end, lock->fl.fl_type);
|
113 |
|
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list_for_each_entry(block, &nlm_blocked, b_list) {
|
114 |
|
|
fl = &block->b_call->a_args.lock.fl;
|
115 |
|
|
dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
|
116 |
|
|
block->b_file, fl->fl_pid,
|
117 |
|
|
(long long)fl->fl_start,
|
118 |
|
|
(long long)fl->fl_end, fl->fl_type,
|
119 |
|
|
nlmdbg_cookie2a(&block->b_call->a_args.cookie));
|
120 |
|
|
if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
|
121 |
|
|
kref_get(&block->b_count);
|
122 |
|
|
return block;
|
123 |
|
|
}
|
124 |
|
|
}
|
125 |
|
|
|
126 |
|
|
return NULL;
|
127 |
|
|
}
|
128 |
|
|
|
129 |
|
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static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
|
130 |
|
|
{
|
131 |
|
|
if(a->len != b->len)
|
132 |
|
|
return 0;
|
133 |
|
|
if(memcmp(a->data,b->data,a->len))
|
134 |
|
|
return 0;
|
135 |
|
|
return 1;
|
136 |
|
|
}
|
137 |
|
|
|
138 |
|
|
/*
|
139 |
|
|
* Find a block with a given NLM cookie.
|
140 |
|
|
*/
|
141 |
|
|
static inline struct nlm_block *
|
142 |
|
|
nlmsvc_find_block(struct nlm_cookie *cookie)
|
143 |
|
|
{
|
144 |
|
|
struct nlm_block *block;
|
145 |
|
|
|
146 |
|
|
list_for_each_entry(block, &nlm_blocked, b_list) {
|
147 |
|
|
if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie))
|
148 |
|
|
goto found;
|
149 |
|
|
}
|
150 |
|
|
|
151 |
|
|
return NULL;
|
152 |
|
|
|
153 |
|
|
found:
|
154 |
|
|
dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block);
|
155 |
|
|
kref_get(&block->b_count);
|
156 |
|
|
return block;
|
157 |
|
|
}
|
158 |
|
|
|
159 |
|
|
/*
|
160 |
|
|
* Create a block and initialize it.
|
161 |
|
|
*
|
162 |
|
|
* Note: we explicitly set the cookie of the grant reply to that of
|
163 |
|
|
* the blocked lock request. The spec explicitly mentions that the client
|
164 |
|
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* should _not_ rely on the callback containing the same cookie as the
|
165 |
|
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* request, but (as I found out later) that's because some implementations
|
166 |
|
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* do just this. Never mind the standards comittees, they support our
|
167 |
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* logging industries.
|
168 |
|
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*
|
169 |
|
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* 10 years later: I hope we can safely ignore these old and broken
|
170 |
|
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* clients by now. Let's fix this so we can uniquely identify an incoming
|
171 |
|
|
* GRANTED_RES message by cookie, without having to rely on the client's IP
|
172 |
|
|
* address. --okir
|
173 |
|
|
*/
|
174 |
|
|
static struct nlm_block *
|
175 |
|
|
nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
|
176 |
|
|
struct nlm_file *file, struct nlm_lock *lock,
|
177 |
|
|
struct nlm_cookie *cookie)
|
178 |
|
|
{
|
179 |
|
|
struct nlm_block *block;
|
180 |
|
|
struct nlm_rqst *call = NULL;
|
181 |
|
|
|
182 |
|
|
call = nlm_alloc_call(host);
|
183 |
|
|
if (call == NULL)
|
184 |
|
|
return NULL;
|
185 |
|
|
|
186 |
|
|
/* Allocate memory for block, and initialize arguments */
|
187 |
|
|
block = kzalloc(sizeof(*block), GFP_KERNEL);
|
188 |
|
|
if (block == NULL)
|
189 |
|
|
goto failed;
|
190 |
|
|
kref_init(&block->b_count);
|
191 |
|
|
INIT_LIST_HEAD(&block->b_list);
|
192 |
|
|
INIT_LIST_HEAD(&block->b_flist);
|
193 |
|
|
|
194 |
|
|
if (!nlmsvc_setgrantargs(call, lock))
|
195 |
|
|
goto failed_free;
|
196 |
|
|
|
197 |
|
|
/* Set notifier function for VFS, and init args */
|
198 |
|
|
call->a_args.lock.fl.fl_flags |= FL_SLEEP;
|
199 |
|
|
call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
|
200 |
|
|
nlmclnt_next_cookie(&call->a_args.cookie);
|
201 |
|
|
|
202 |
|
|
dprintk("lockd: created block %p...\n", block);
|
203 |
|
|
|
204 |
|
|
/* Create and initialize the block */
|
205 |
|
|
block->b_daemon = rqstp->rq_server;
|
206 |
|
|
block->b_host = host;
|
207 |
|
|
block->b_file = file;
|
208 |
|
|
block->b_fl = NULL;
|
209 |
|
|
file->f_count++;
|
210 |
|
|
|
211 |
|
|
/* Add to file's list of blocks */
|
212 |
|
|
list_add(&block->b_flist, &file->f_blocks);
|
213 |
|
|
|
214 |
|
|
/* Set up RPC arguments for callback */
|
215 |
|
|
block->b_call = call;
|
216 |
|
|
call->a_flags = RPC_TASK_ASYNC;
|
217 |
|
|
call->a_block = block;
|
218 |
|
|
|
219 |
|
|
return block;
|
220 |
|
|
|
221 |
|
|
failed_free:
|
222 |
|
|
kfree(block);
|
223 |
|
|
failed:
|
224 |
|
|
nlm_release_call(call);
|
225 |
|
|
return NULL;
|
226 |
|
|
}
|
227 |
|
|
|
228 |
|
|
/*
|
229 |
|
|
* Delete a block. If the lock was cancelled or the grant callback
|
230 |
|
|
* failed, unlock is set to 1.
|
231 |
|
|
* It is the caller's responsibility to check whether the file
|
232 |
|
|
* can be closed hereafter.
|
233 |
|
|
*/
|
234 |
|
|
static int nlmsvc_unlink_block(struct nlm_block *block)
|
235 |
|
|
{
|
236 |
|
|
int status;
|
237 |
|
|
dprintk("lockd: unlinking block %p...\n", block);
|
238 |
|
|
|
239 |
|
|
/* Remove block from list */
|
240 |
|
|
status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
|
241 |
|
|
nlmsvc_remove_block(block);
|
242 |
|
|
return status;
|
243 |
|
|
}
|
244 |
|
|
|
245 |
|
|
static void nlmsvc_free_block(struct kref *kref)
|
246 |
|
|
{
|
247 |
|
|
struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
|
248 |
|
|
struct nlm_file *file = block->b_file;
|
249 |
|
|
|
250 |
|
|
dprintk("lockd: freeing block %p...\n", block);
|
251 |
|
|
|
252 |
|
|
/* Remove block from file's list of blocks */
|
253 |
|
|
mutex_lock(&file->f_mutex);
|
254 |
|
|
list_del_init(&block->b_flist);
|
255 |
|
|
mutex_unlock(&file->f_mutex);
|
256 |
|
|
|
257 |
|
|
nlmsvc_freegrantargs(block->b_call);
|
258 |
|
|
nlm_release_call(block->b_call);
|
259 |
|
|
nlm_release_file(block->b_file);
|
260 |
|
|
kfree(block->b_fl);
|
261 |
|
|
kfree(block);
|
262 |
|
|
}
|
263 |
|
|
|
264 |
|
|
static void nlmsvc_release_block(struct nlm_block *block)
|
265 |
|
|
{
|
266 |
|
|
if (block != NULL)
|
267 |
|
|
kref_put(&block->b_count, nlmsvc_free_block);
|
268 |
|
|
}
|
269 |
|
|
|
270 |
|
|
/*
|
271 |
|
|
* Loop over all blocks and delete blocks held by
|
272 |
|
|
* a matching host.
|
273 |
|
|
*/
|
274 |
|
|
void nlmsvc_traverse_blocks(struct nlm_host *host,
|
275 |
|
|
struct nlm_file *file,
|
276 |
|
|
nlm_host_match_fn_t match)
|
277 |
|
|
{
|
278 |
|
|
struct nlm_block *block, *next;
|
279 |
|
|
|
280 |
|
|
restart:
|
281 |
|
|
mutex_lock(&file->f_mutex);
|
282 |
|
|
list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
|
283 |
|
|
if (!match(block->b_host, host))
|
284 |
|
|
continue;
|
285 |
|
|
/* Do not destroy blocks that are not on
|
286 |
|
|
* the global retry list - why? */
|
287 |
|
|
if (list_empty(&block->b_list))
|
288 |
|
|
continue;
|
289 |
|
|
kref_get(&block->b_count);
|
290 |
|
|
mutex_unlock(&file->f_mutex);
|
291 |
|
|
nlmsvc_unlink_block(block);
|
292 |
|
|
nlmsvc_release_block(block);
|
293 |
|
|
goto restart;
|
294 |
|
|
}
|
295 |
|
|
mutex_unlock(&file->f_mutex);
|
296 |
|
|
}
|
297 |
|
|
|
298 |
|
|
/*
|
299 |
|
|
* Initialize arguments for GRANTED call. The nlm_rqst structure
|
300 |
|
|
* has been cleared already.
|
301 |
|
|
*/
|
302 |
|
|
static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
|
303 |
|
|
{
|
304 |
|
|
locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
|
305 |
|
|
memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
|
306 |
|
|
call->a_args.lock.caller = utsname()->nodename;
|
307 |
|
|
call->a_args.lock.oh.len = lock->oh.len;
|
308 |
|
|
|
309 |
|
|
/* set default data area */
|
310 |
|
|
call->a_args.lock.oh.data = call->a_owner;
|
311 |
|
|
call->a_args.lock.svid = lock->fl.fl_pid;
|
312 |
|
|
|
313 |
|
|
if (lock->oh.len > NLMCLNT_OHSIZE) {
|
314 |
|
|
void *data = kmalloc(lock->oh.len, GFP_KERNEL);
|
315 |
|
|
if (!data)
|
316 |
|
|
return 0;
|
317 |
|
|
call->a_args.lock.oh.data = (u8 *) data;
|
318 |
|
|
}
|
319 |
|
|
|
320 |
|
|
memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
|
321 |
|
|
return 1;
|
322 |
|
|
}
|
323 |
|
|
|
324 |
|
|
static void nlmsvc_freegrantargs(struct nlm_rqst *call)
|
325 |
|
|
{
|
326 |
|
|
if (call->a_args.lock.oh.data != call->a_owner)
|
327 |
|
|
kfree(call->a_args.lock.oh.data);
|
328 |
|
|
}
|
329 |
|
|
|
330 |
|
|
/*
|
331 |
|
|
* Deferred lock request handling for non-blocking lock
|
332 |
|
|
*/
|
333 |
|
|
static __be32
|
334 |
|
|
nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
|
335 |
|
|
{
|
336 |
|
|
__be32 status = nlm_lck_denied_nolocks;
|
337 |
|
|
|
338 |
|
|
block->b_flags |= B_QUEUED;
|
339 |
|
|
|
340 |
|
|
nlmsvc_insert_block(block, NLM_TIMEOUT);
|
341 |
|
|
|
342 |
|
|
block->b_cache_req = &rqstp->rq_chandle;
|
343 |
|
|
if (rqstp->rq_chandle.defer) {
|
344 |
|
|
block->b_deferred_req =
|
345 |
|
|
rqstp->rq_chandle.defer(block->b_cache_req);
|
346 |
|
|
if (block->b_deferred_req != NULL)
|
347 |
|
|
status = nlm_drop_reply;
|
348 |
|
|
}
|
349 |
|
|
dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
|
350 |
|
|
block, block->b_flags, ntohl(status));
|
351 |
|
|
|
352 |
|
|
return status;
|
353 |
|
|
}
|
354 |
|
|
|
355 |
|
|
/*
|
356 |
|
|
* Attempt to establish a lock, and if it can't be granted, block it
|
357 |
|
|
* if required.
|
358 |
|
|
*/
|
359 |
|
|
__be32
|
360 |
|
|
nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
|
361 |
|
|
struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
|
362 |
|
|
{
|
363 |
|
|
struct nlm_block *block = NULL;
|
364 |
|
|
struct nlm_host *host;
|
365 |
|
|
int error;
|
366 |
|
|
__be32 ret;
|
367 |
|
|
|
368 |
|
|
dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
|
369 |
|
|
file->f_file->f_path.dentry->d_inode->i_sb->s_id,
|
370 |
|
|
file->f_file->f_path.dentry->d_inode->i_ino,
|
371 |
|
|
lock->fl.fl_type, lock->fl.fl_pid,
|
372 |
|
|
(long long)lock->fl.fl_start,
|
373 |
|
|
(long long)lock->fl.fl_end,
|
374 |
|
|
wait);
|
375 |
|
|
|
376 |
|
|
/* Create host handle for callback */
|
377 |
|
|
host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
|
378 |
|
|
if (host == NULL)
|
379 |
|
|
return nlm_lck_denied_nolocks;
|
380 |
|
|
|
381 |
|
|
/* Lock file against concurrent access */
|
382 |
|
|
mutex_lock(&file->f_mutex);
|
383 |
|
|
/* Get existing block (in case client is busy-waiting)
|
384 |
|
|
* or create new block
|
385 |
|
|
*/
|
386 |
|
|
block = nlmsvc_lookup_block(file, lock);
|
387 |
|
|
if (block == NULL) {
|
388 |
|
|
block = nlmsvc_create_block(rqstp, nlm_get_host(host), file,
|
389 |
|
|
lock, cookie);
|
390 |
|
|
ret = nlm_lck_denied_nolocks;
|
391 |
|
|
if (block == NULL)
|
392 |
|
|
goto out;
|
393 |
|
|
lock = &block->b_call->a_args.lock;
|
394 |
|
|
} else
|
395 |
|
|
lock->fl.fl_flags &= ~FL_SLEEP;
|
396 |
|
|
|
397 |
|
|
if (block->b_flags & B_QUEUED) {
|
398 |
|
|
dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
|
399 |
|
|
block, block->b_flags);
|
400 |
|
|
if (block->b_granted) {
|
401 |
|
|
nlmsvc_unlink_block(block);
|
402 |
|
|
ret = nlm_granted;
|
403 |
|
|
goto out;
|
404 |
|
|
}
|
405 |
|
|
if (block->b_flags & B_TIMED_OUT) {
|
406 |
|
|
nlmsvc_unlink_block(block);
|
407 |
|
|
ret = nlm_lck_denied;
|
408 |
|
|
goto out;
|
409 |
|
|
}
|
410 |
|
|
ret = nlm_drop_reply;
|
411 |
|
|
goto out;
|
412 |
|
|
}
|
413 |
|
|
|
414 |
|
|
if (!wait)
|
415 |
|
|
lock->fl.fl_flags &= ~FL_SLEEP;
|
416 |
|
|
error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
|
417 |
|
|
lock->fl.fl_flags &= ~FL_SLEEP;
|
418 |
|
|
|
419 |
|
|
dprintk("lockd: vfs_lock_file returned %d\n", error);
|
420 |
|
|
switch(error) {
|
421 |
|
|
case 0:
|
422 |
|
|
ret = nlm_granted;
|
423 |
|
|
goto out;
|
424 |
|
|
case -EAGAIN:
|
425 |
|
|
ret = nlm_lck_denied;
|
426 |
|
|
break;
|
427 |
|
|
case -EINPROGRESS:
|
428 |
|
|
if (wait)
|
429 |
|
|
break;
|
430 |
|
|
/* Filesystem lock operation is in progress
|
431 |
|
|
Add it to the queue waiting for callback */
|
432 |
|
|
ret = nlmsvc_defer_lock_rqst(rqstp, block);
|
433 |
|
|
goto out;
|
434 |
|
|
case -EDEADLK:
|
435 |
|
|
ret = nlm_deadlock;
|
436 |
|
|
goto out;
|
437 |
|
|
default: /* includes ENOLCK */
|
438 |
|
|
ret = nlm_lck_denied_nolocks;
|
439 |
|
|
goto out;
|
440 |
|
|
}
|
441 |
|
|
|
442 |
|
|
ret = nlm_lck_denied;
|
443 |
|
|
if (!wait)
|
444 |
|
|
goto out;
|
445 |
|
|
|
446 |
|
|
ret = nlm_lck_blocked;
|
447 |
|
|
|
448 |
|
|
/* Append to list of blocked */
|
449 |
|
|
nlmsvc_insert_block(block, NLM_NEVER);
|
450 |
|
|
out:
|
451 |
|
|
mutex_unlock(&file->f_mutex);
|
452 |
|
|
nlmsvc_release_block(block);
|
453 |
|
|
nlm_release_host(host);
|
454 |
|
|
dprintk("lockd: nlmsvc_lock returned %u\n", ret);
|
455 |
|
|
return ret;
|
456 |
|
|
}
|
457 |
|
|
|
458 |
|
|
/*
|
459 |
|
|
* Test for presence of a conflicting lock.
|
460 |
|
|
*/
|
461 |
|
|
__be32
|
462 |
|
|
nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
|
463 |
|
|
struct nlm_lock *lock, struct nlm_lock *conflock,
|
464 |
|
|
struct nlm_cookie *cookie)
|
465 |
|
|
{
|
466 |
|
|
struct nlm_block *block = NULL;
|
467 |
|
|
int error;
|
468 |
|
|
__be32 ret;
|
469 |
|
|
|
470 |
|
|
dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
|
471 |
|
|
file->f_file->f_path.dentry->d_inode->i_sb->s_id,
|
472 |
|
|
file->f_file->f_path.dentry->d_inode->i_ino,
|
473 |
|
|
lock->fl.fl_type,
|
474 |
|
|
(long long)lock->fl.fl_start,
|
475 |
|
|
(long long)lock->fl.fl_end);
|
476 |
|
|
|
477 |
|
|
/* Get existing block (in case client is busy-waiting) */
|
478 |
|
|
block = nlmsvc_lookup_block(file, lock);
|
479 |
|
|
|
480 |
|
|
if (block == NULL) {
|
481 |
|
|
struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
|
482 |
|
|
struct nlm_host *host;
|
483 |
|
|
|
484 |
|
|
if (conf == NULL)
|
485 |
|
|
return nlm_granted;
|
486 |
|
|
/* Create host handle for callback */
|
487 |
|
|
host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
|
488 |
|
|
if (host == NULL) {
|
489 |
|
|
kfree(conf);
|
490 |
|
|
return nlm_lck_denied_nolocks;
|
491 |
|
|
}
|
492 |
|
|
block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
|
493 |
|
|
if (block == NULL) {
|
494 |
|
|
kfree(conf);
|
495 |
|
|
return nlm_granted;
|
496 |
|
|
}
|
497 |
|
|
block->b_fl = conf;
|
498 |
|
|
}
|
499 |
|
|
if (block->b_flags & B_QUEUED) {
|
500 |
|
|
dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
|
501 |
|
|
block, block->b_flags, block->b_fl);
|
502 |
|
|
if (block->b_flags & B_TIMED_OUT) {
|
503 |
|
|
nlmsvc_unlink_block(block);
|
504 |
|
|
return nlm_lck_denied;
|
505 |
|
|
}
|
506 |
|
|
if (block->b_flags & B_GOT_CALLBACK) {
|
507 |
|
|
if (block->b_fl != NULL
|
508 |
|
|
&& block->b_fl->fl_type != F_UNLCK) {
|
509 |
|
|
lock->fl = *block->b_fl;
|
510 |
|
|
goto conf_lock;
|
511 |
|
|
}
|
512 |
|
|
else {
|
513 |
|
|
nlmsvc_unlink_block(block);
|
514 |
|
|
return nlm_granted;
|
515 |
|
|
}
|
516 |
|
|
}
|
517 |
|
|
return nlm_drop_reply;
|
518 |
|
|
}
|
519 |
|
|
|
520 |
|
|
error = vfs_test_lock(file->f_file, &lock->fl);
|
521 |
|
|
if (error == -EINPROGRESS)
|
522 |
|
|
return nlmsvc_defer_lock_rqst(rqstp, block);
|
523 |
|
|
if (error) {
|
524 |
|
|
ret = nlm_lck_denied_nolocks;
|
525 |
|
|
goto out;
|
526 |
|
|
}
|
527 |
|
|
if (lock->fl.fl_type == F_UNLCK) {
|
528 |
|
|
ret = nlm_granted;
|
529 |
|
|
goto out;
|
530 |
|
|
}
|
531 |
|
|
|
532 |
|
|
conf_lock:
|
533 |
|
|
dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
|
534 |
|
|
lock->fl.fl_type, (long long)lock->fl.fl_start,
|
535 |
|
|
(long long)lock->fl.fl_end);
|
536 |
|
|
conflock->caller = "somehost"; /* FIXME */
|
537 |
|
|
conflock->len = strlen(conflock->caller);
|
538 |
|
|
conflock->oh.len = 0; /* don't return OH info */
|
539 |
|
|
conflock->svid = lock->fl.fl_pid;
|
540 |
|
|
conflock->fl.fl_type = lock->fl.fl_type;
|
541 |
|
|
conflock->fl.fl_start = lock->fl.fl_start;
|
542 |
|
|
conflock->fl.fl_end = lock->fl.fl_end;
|
543 |
|
|
ret = nlm_lck_denied;
|
544 |
|
|
out:
|
545 |
|
|
if (block)
|
546 |
|
|
nlmsvc_release_block(block);
|
547 |
|
|
return ret;
|
548 |
|
|
}
|
549 |
|
|
|
550 |
|
|
/*
|
551 |
|
|
* Remove a lock.
|
552 |
|
|
* This implies a CANCEL call: We send a GRANT_MSG, the client replies
|
553 |
|
|
* with a GRANT_RES call which gets lost, and calls UNLOCK immediately
|
554 |
|
|
* afterwards. In this case the block will still be there, and hence
|
555 |
|
|
* must be removed.
|
556 |
|
|
*/
|
557 |
|
|
__be32
|
558 |
|
|
nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
|
559 |
|
|
{
|
560 |
|
|
int error;
|
561 |
|
|
|
562 |
|
|
dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
|
563 |
|
|
file->f_file->f_path.dentry->d_inode->i_sb->s_id,
|
564 |
|
|
file->f_file->f_path.dentry->d_inode->i_ino,
|
565 |
|
|
lock->fl.fl_pid,
|
566 |
|
|
(long long)lock->fl.fl_start,
|
567 |
|
|
(long long)lock->fl.fl_end);
|
568 |
|
|
|
569 |
|
|
/* First, cancel any lock that might be there */
|
570 |
|
|
nlmsvc_cancel_blocked(file, lock);
|
571 |
|
|
|
572 |
|
|
lock->fl.fl_type = F_UNLCK;
|
573 |
|
|
error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
|
574 |
|
|
|
575 |
|
|
return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
|
576 |
|
|
}
|
577 |
|
|
|
578 |
|
|
/*
|
579 |
|
|
* Cancel a previously blocked request.
|
580 |
|
|
*
|
581 |
|
|
* A cancel request always overrides any grant that may currently
|
582 |
|
|
* be in progress.
|
583 |
|
|
* The calling procedure must check whether the file can be closed.
|
584 |
|
|
*/
|
585 |
|
|
__be32
|
586 |
|
|
nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
|
587 |
|
|
{
|
588 |
|
|
struct nlm_block *block;
|
589 |
|
|
int status = 0;
|
590 |
|
|
|
591 |
|
|
dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
|
592 |
|
|
file->f_file->f_path.dentry->d_inode->i_sb->s_id,
|
593 |
|
|
file->f_file->f_path.dentry->d_inode->i_ino,
|
594 |
|
|
lock->fl.fl_pid,
|
595 |
|
|
(long long)lock->fl.fl_start,
|
596 |
|
|
(long long)lock->fl.fl_end);
|
597 |
|
|
|
598 |
|
|
mutex_lock(&file->f_mutex);
|
599 |
|
|
block = nlmsvc_lookup_block(file, lock);
|
600 |
|
|
mutex_unlock(&file->f_mutex);
|
601 |
|
|
if (block != NULL) {
|
602 |
|
|
vfs_cancel_lock(block->b_file->f_file,
|
603 |
|
|
&block->b_call->a_args.lock.fl);
|
604 |
|
|
status = nlmsvc_unlink_block(block);
|
605 |
|
|
nlmsvc_release_block(block);
|
606 |
|
|
}
|
607 |
|
|
return status ? nlm_lck_denied : nlm_granted;
|
608 |
|
|
}
|
609 |
|
|
|
610 |
|
|
/*
|
611 |
|
|
* This is a callback from the filesystem for VFS file lock requests.
|
612 |
|
|
* It will be used if fl_grant is defined and the filesystem can not
|
613 |
|
|
* respond to the request immediately.
|
614 |
|
|
* For GETLK request it will copy the reply to the nlm_block.
|
615 |
|
|
* For SETLK or SETLKW request it will get the local posix lock.
|
616 |
|
|
* In all cases it will move the block to the head of nlm_blocked q where
|
617 |
|
|
* nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
|
618 |
|
|
* deferred rpc for GETLK and SETLK.
|
619 |
|
|
*/
|
620 |
|
|
static void
|
621 |
|
|
nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf,
|
622 |
|
|
int result)
|
623 |
|
|
{
|
624 |
|
|
block->b_flags |= B_GOT_CALLBACK;
|
625 |
|
|
if (result == 0)
|
626 |
|
|
block->b_granted = 1;
|
627 |
|
|
else
|
628 |
|
|
block->b_flags |= B_TIMED_OUT;
|
629 |
|
|
if (conf) {
|
630 |
|
|
if (block->b_fl)
|
631 |
|
|
locks_copy_lock(block->b_fl, conf);
|
632 |
|
|
}
|
633 |
|
|
}
|
634 |
|
|
|
635 |
|
|
static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
|
636 |
|
|
int result)
|
637 |
|
|
{
|
638 |
|
|
struct nlm_block *block;
|
639 |
|
|
int rc = -ENOENT;
|
640 |
|
|
|
641 |
|
|
lock_kernel();
|
642 |
|
|
list_for_each_entry(block, &nlm_blocked, b_list) {
|
643 |
|
|
if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
|
644 |
|
|
dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
|
645 |
|
|
block, block->b_flags);
|
646 |
|
|
if (block->b_flags & B_QUEUED) {
|
647 |
|
|
if (block->b_flags & B_TIMED_OUT) {
|
648 |
|
|
rc = -ENOLCK;
|
649 |
|
|
break;
|
650 |
|
|
}
|
651 |
|
|
nlmsvc_update_deferred_block(block, conf, result);
|
652 |
|
|
} else if (result == 0)
|
653 |
|
|
block->b_granted = 1;
|
654 |
|
|
|
655 |
|
|
nlmsvc_insert_block(block, 0);
|
656 |
|
|
svc_wake_up(block->b_daemon);
|
657 |
|
|
rc = 0;
|
658 |
|
|
break;
|
659 |
|
|
}
|
660 |
|
|
}
|
661 |
|
|
unlock_kernel();
|
662 |
|
|
if (rc == -ENOENT)
|
663 |
|
|
printk(KERN_WARNING "lockd: grant for unknown block\n");
|
664 |
|
|
return rc;
|
665 |
|
|
}
|
666 |
|
|
|
667 |
|
|
/*
|
668 |
|
|
* Unblock a blocked lock request. This is a callback invoked from the
|
669 |
|
|
* VFS layer when a lock on which we blocked is removed.
|
670 |
|
|
*
|
671 |
|
|
* This function doesn't grant the blocked lock instantly, but rather moves
|
672 |
|
|
* the block to the head of nlm_blocked where it can be picked up by lockd.
|
673 |
|
|
*/
|
674 |
|
|
static void
|
675 |
|
|
nlmsvc_notify_blocked(struct file_lock *fl)
|
676 |
|
|
{
|
677 |
|
|
struct nlm_block *block;
|
678 |
|
|
|
679 |
|
|
dprintk("lockd: VFS unblock notification for block %p\n", fl);
|
680 |
|
|
list_for_each_entry(block, &nlm_blocked, b_list) {
|
681 |
|
|
if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
|
682 |
|
|
nlmsvc_insert_block(block, 0);
|
683 |
|
|
svc_wake_up(block->b_daemon);
|
684 |
|
|
return;
|
685 |
|
|
}
|
686 |
|
|
}
|
687 |
|
|
|
688 |
|
|
printk(KERN_WARNING "lockd: notification for unknown block!\n");
|
689 |
|
|
}
|
690 |
|
|
|
691 |
|
|
static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
|
692 |
|
|
{
|
693 |
|
|
return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
|
694 |
|
|
}
|
695 |
|
|
|
696 |
|
|
struct lock_manager_operations nlmsvc_lock_operations = {
|
697 |
|
|
.fl_compare_owner = nlmsvc_same_owner,
|
698 |
|
|
.fl_notify = nlmsvc_notify_blocked,
|
699 |
|
|
.fl_grant = nlmsvc_grant_deferred,
|
700 |
|
|
};
|
701 |
|
|
|
702 |
|
|
/*
|
703 |
|
|
* Try to claim a lock that was previously blocked.
|
704 |
|
|
*
|
705 |
|
|
* Note that we use both the RPC_GRANTED_MSG call _and_ an async
|
706 |
|
|
* RPC thread when notifying the client. This seems like overkill...
|
707 |
|
|
* Here's why:
|
708 |
|
|
* - we don't want to use a synchronous RPC thread, otherwise
|
709 |
|
|
* we might find ourselves hanging on a dead portmapper.
|
710 |
|
|
* - Some lockd implementations (e.g. HP) don't react to
|
711 |
|
|
* RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
|
712 |
|
|
*/
|
713 |
|
|
static void
|
714 |
|
|
nlmsvc_grant_blocked(struct nlm_block *block)
|
715 |
|
|
{
|
716 |
|
|
struct nlm_file *file = block->b_file;
|
717 |
|
|
struct nlm_lock *lock = &block->b_call->a_args.lock;
|
718 |
|
|
int error;
|
719 |
|
|
|
720 |
|
|
dprintk("lockd: grant blocked lock %p\n", block);
|
721 |
|
|
|
722 |
|
|
kref_get(&block->b_count);
|
723 |
|
|
|
724 |
|
|
/* Unlink block request from list */
|
725 |
|
|
nlmsvc_unlink_block(block);
|
726 |
|
|
|
727 |
|
|
/* If b_granted is true this means we've been here before.
|
728 |
|
|
* Just retry the grant callback, possibly refreshing the RPC
|
729 |
|
|
* binding */
|
730 |
|
|
if (block->b_granted) {
|
731 |
|
|
nlm_rebind_host(block->b_host);
|
732 |
|
|
goto callback;
|
733 |
|
|
}
|
734 |
|
|
|
735 |
|
|
/* Try the lock operation again */
|
736 |
|
|
lock->fl.fl_flags |= FL_SLEEP;
|
737 |
|
|
error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
|
738 |
|
|
lock->fl.fl_flags &= ~FL_SLEEP;
|
739 |
|
|
|
740 |
|
|
switch (error) {
|
741 |
|
|
case 0:
|
742 |
|
|
break;
|
743 |
|
|
case -EAGAIN:
|
744 |
|
|
case -EINPROGRESS:
|
745 |
|
|
dprintk("lockd: lock still blocked error %d\n", error);
|
746 |
|
|
nlmsvc_insert_block(block, NLM_NEVER);
|
747 |
|
|
nlmsvc_release_block(block);
|
748 |
|
|
return;
|
749 |
|
|
default:
|
750 |
|
|
printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
|
751 |
|
|
-error, __FUNCTION__);
|
752 |
|
|
nlmsvc_insert_block(block, 10 * HZ);
|
753 |
|
|
nlmsvc_release_block(block);
|
754 |
|
|
return;
|
755 |
|
|
}
|
756 |
|
|
|
757 |
|
|
callback:
|
758 |
|
|
/* Lock was granted by VFS. */
|
759 |
|
|
dprintk("lockd: GRANTing blocked lock.\n");
|
760 |
|
|
block->b_granted = 1;
|
761 |
|
|
|
762 |
|
|
/* Schedule next grant callback in 30 seconds */
|
763 |
|
|
nlmsvc_insert_block(block, 30 * HZ);
|
764 |
|
|
|
765 |
|
|
/* Call the client */
|
766 |
|
|
nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, &nlmsvc_grant_ops);
|
767 |
|
|
}
|
768 |
|
|
|
769 |
|
|
/*
|
770 |
|
|
* This is the callback from the RPC layer when the NLM_GRANTED_MSG
|
771 |
|
|
* RPC call has succeeded or timed out.
|
772 |
|
|
* Like all RPC callbacks, it is invoked by the rpciod process, so it
|
773 |
|
|
* better not sleep. Therefore, we put the blocked lock on the nlm_blocked
|
774 |
|
|
* chain once more in order to have it removed by lockd itself (which can
|
775 |
|
|
* then sleep on the file semaphore without disrupting e.g. the nfs client).
|
776 |
|
|
*/
|
777 |
|
|
static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
|
778 |
|
|
{
|
779 |
|
|
struct nlm_rqst *call = data;
|
780 |
|
|
struct nlm_block *block = call->a_block;
|
781 |
|
|
unsigned long timeout;
|
782 |
|
|
|
783 |
|
|
dprintk("lockd: GRANT_MSG RPC callback\n");
|
784 |
|
|
|
785 |
|
|
/* Technically, we should down the file semaphore here. Since we
|
786 |
|
|
* move the block towards the head of the queue only, no harm
|
787 |
|
|
* can be done, though. */
|
788 |
|
|
if (task->tk_status < 0) {
|
789 |
|
|
/* RPC error: Re-insert for retransmission */
|
790 |
|
|
timeout = 10 * HZ;
|
791 |
|
|
} else {
|
792 |
|
|
/* Call was successful, now wait for client callback */
|
793 |
|
|
timeout = 60 * HZ;
|
794 |
|
|
}
|
795 |
|
|
nlmsvc_insert_block(block, timeout);
|
796 |
|
|
svc_wake_up(block->b_daemon);
|
797 |
|
|
}
|
798 |
|
|
|
799 |
|
|
static void nlmsvc_grant_release(void *data)
|
800 |
|
|
{
|
801 |
|
|
struct nlm_rqst *call = data;
|
802 |
|
|
|
803 |
|
|
nlmsvc_release_block(call->a_block);
|
804 |
|
|
}
|
805 |
|
|
|
806 |
|
|
static const struct rpc_call_ops nlmsvc_grant_ops = {
|
807 |
|
|
.rpc_call_done = nlmsvc_grant_callback,
|
808 |
|
|
.rpc_release = nlmsvc_grant_release,
|
809 |
|
|
};
|
810 |
|
|
|
811 |
|
|
/*
|
812 |
|
|
* We received a GRANT_RES callback. Try to find the corresponding
|
813 |
|
|
* block.
|
814 |
|
|
*/
|
815 |
|
|
void
|
816 |
|
|
nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
|
817 |
|
|
{
|
818 |
|
|
struct nlm_block *block;
|
819 |
|
|
|
820 |
|
|
dprintk("grant_reply: looking for cookie %x, s=%d \n",
|
821 |
|
|
*(unsigned int *)(cookie->data), status);
|
822 |
|
|
if (!(block = nlmsvc_find_block(cookie)))
|
823 |
|
|
return;
|
824 |
|
|
|
825 |
|
|
if (block) {
|
826 |
|
|
if (status == nlm_lck_denied_grace_period) {
|
827 |
|
|
/* Try again in a couple of seconds */
|
828 |
|
|
nlmsvc_insert_block(block, 10 * HZ);
|
829 |
|
|
} else {
|
830 |
|
|
/* Lock is now held by client, or has been rejected.
|
831 |
|
|
* In both cases, the block should be removed. */
|
832 |
|
|
nlmsvc_unlink_block(block);
|
833 |
|
|
}
|
834 |
|
|
}
|
835 |
|
|
nlmsvc_release_block(block);
|
836 |
|
|
}
|
837 |
|
|
|
838 |
|
|
/* Helper function to handle retry of a deferred block.
|
839 |
|
|
* If it is a blocking lock, call grant_blocked.
|
840 |
|
|
* For a non-blocking lock or test lock, revisit the request.
|
841 |
|
|
*/
|
842 |
|
|
static void
|
843 |
|
|
retry_deferred_block(struct nlm_block *block)
|
844 |
|
|
{
|
845 |
|
|
if (!(block->b_flags & B_GOT_CALLBACK))
|
846 |
|
|
block->b_flags |= B_TIMED_OUT;
|
847 |
|
|
nlmsvc_insert_block(block, NLM_TIMEOUT);
|
848 |
|
|
dprintk("revisit block %p flags %d\n", block, block->b_flags);
|
849 |
|
|
if (block->b_deferred_req) {
|
850 |
|
|
block->b_deferred_req->revisit(block->b_deferred_req, 0);
|
851 |
|
|
block->b_deferred_req = NULL;
|
852 |
|
|
}
|
853 |
|
|
}
|
854 |
|
|
|
855 |
|
|
/*
|
856 |
|
|
* Retry all blocked locks that have been notified. This is where lockd
|
857 |
|
|
* picks up locks that can be granted, or grant notifications that must
|
858 |
|
|
* be retransmitted.
|
859 |
|
|
*/
|
860 |
|
|
unsigned long
|
861 |
|
|
nlmsvc_retry_blocked(void)
|
862 |
|
|
{
|
863 |
|
|
unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
|
864 |
|
|
struct nlm_block *block;
|
865 |
|
|
|
866 |
|
|
while (!list_empty(&nlm_blocked)) {
|
867 |
|
|
block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
|
868 |
|
|
|
869 |
|
|
if (block->b_when == NLM_NEVER)
|
870 |
|
|
break;
|
871 |
|
|
if (time_after(block->b_when,jiffies)) {
|
872 |
|
|
timeout = block->b_when - jiffies;
|
873 |
|
|
break;
|
874 |
|
|
}
|
875 |
|
|
|
876 |
|
|
dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
|
877 |
|
|
block, block->b_when);
|
878 |
|
|
if (block->b_flags & B_QUEUED) {
|
879 |
|
|
dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
|
880 |
|
|
block, block->b_granted, block->b_flags);
|
881 |
|
|
retry_deferred_block(block);
|
882 |
|
|
} else
|
883 |
|
|
nlmsvc_grant_blocked(block);
|
884 |
|
|
}
|
885 |
|
|
|
886 |
|
|
return timeout;
|
887 |
|
|
}
|