1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/*
* linux/fs/lockd/clntlock.c
*
* Lock handling for the client side NLM implementation
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/time.h>
#include <linux/nfs_fs.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/smp_lock.h>
#define NLMDBG_FACILITY NLMDBG_CLIENT
/*
* Local function prototypes
*/
static int reclaimer(void *ptr);
/*
* The following functions handle blocking and granting from the
* client perspective.
*/
/*
* This is the representation of a blocked client lock.
*/
struct nlm_wait {
struct list_head b_list; /* linked list */
wait_queue_head_t b_wait; /* where to wait on */
struct nlm_host * b_host;
struct file_lock * b_lock; /* local file lock */
unsigned short b_reclaim; /* got to reclaim lock */
u32 b_status; /* grant callback status */
};
static LIST_HEAD(nlm_blocked);
/*
* Block on a lock
*/
int
nlmclnt_block(struct nlm_host *host, struct file_lock *fl, u32 *statp)
{
struct nlm_wait block, **head;
int err;
u32 pstate;
block.b_host = host;
block.b_lock = fl;
init_waitqueue_head(&block.b_wait);
block.b_status = NLM_LCK_BLOCKED;
list_add(&block.b_list, &nlm_blocked);
/* Remember pseudo nsm state */
pstate = host->h_state;
/* Go to sleep waiting for GRANT callback. Some servers seem
* to lose callbacks, however, so we're going to poll from
* time to time just to make sure.
*
* For now, the retry frequency is pretty high; normally
* a 1 minute timeout would do. See the comment before
* nlmclnt_lock for an explanation.
*/
sleep_on_timeout(&block.b_wait, 30*HZ);
list_del(&block.b_list);
if (!signalled()) {
*statp = block.b_status;
return 0;
}
/* Okay, we were interrupted. Cancel the pending request
* unless the server has rebooted.
*/
if (pstate == host->h_state && (err = nlmclnt_cancel(host, fl)) < 0)
printk(KERN_NOTICE
"lockd: CANCEL call failed (errno %d)\n", -err);
return -ERESTARTSYS;
}
/*
* The server lockd has called us back to tell us the lock was granted
*/
u32
nlmclnt_grant(struct nlm_lock *lock)
{
struct nlm_wait *block;
/*
* Look up blocked request based on arguments.
* Warning: must not use cookie to match it!
*/
list_for_each_entry(block, &nlm_blocked, b_list) {
if (nlm_compare_locks(block->b_lock, &lock->fl))
break;
}
/* Ooops, no blocked request found. */
if (block == NULL)
return nlm_lck_denied;
/* Alright, we found the lock. Set the return status and
* wake up the caller.
*/
block->b_status = NLM_LCK_GRANTED;
wake_up(&block->b_wait);
return nlm_granted;
}
/*
* The following procedures deal with the recovery of locks after a
* server crash.
*/
/*
* Mark the locks for reclaiming.
* FIXME: In 2.5 we don't want to iterate through any global file_lock_list.
* Maintain NLM lock reclaiming lists in the nlm_host instead.
*/
static
void nlmclnt_mark_reclaim(struct nlm_host *host)
{
struct file_lock *fl;
struct inode *inode;
struct list_head *tmp;
list_for_each(tmp, &file_lock_list) {
fl = list_entry(tmp, struct file_lock, fl_link);
inode = fl->fl_file->f_dentry->d_inode;
if (inode->i_sb->s_magic != NFS_SUPER_MAGIC)
continue;
if (fl->fl_u.nfs_fl.owner->host != host)
continue;
if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_GRANTED))
continue;
fl->fl_u.nfs_fl.flags |= NFS_LCK_RECLAIM;
}
}
/*
* Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number,
* that we mark locks for reclaiming, and that we bump the pseudo NSM state.
*/
static inline
void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate)
{
host->h_monitored = 0;
host->h_nsmstate = newstate;
host->h_state++;
host->h_nextrebind = 0;
nlm_rebind_host(host);
nlmclnt_mark_reclaim(host);
dprintk("NLM: reclaiming locks for host %s", host->h_name);
}
/*
* Reclaim all locks on server host. We do this by spawning a separate
* reclaimer thread.
*/
void
nlmclnt_recovery(struct nlm_host *host, u32 newstate)
{
if (host->h_reclaiming++) {
if (host->h_nsmstate == newstate)
return;
nlmclnt_prepare_reclaim(host, newstate);
} else {
nlmclnt_prepare_reclaim(host, newstate);
nlm_get_host(host);
__module_get(THIS_MODULE);
if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
module_put(THIS_MODULE);
}
}
static int
reclaimer(void *ptr)
{
struct nlm_host *host = (struct nlm_host *) ptr;
struct nlm_wait *block;
struct list_head *tmp;
struct file_lock *fl;
struct inode *inode;
daemonize("%s-reclaim", host->h_name);
allow_signal(SIGKILL);
/* This one ensures that our parent doesn't terminate while the
* reclaim is in progress */
lock_kernel();
lockd_up();
/* First, reclaim all locks that have been marked. */
restart:
list_for_each(tmp, &file_lock_list) {
fl = list_entry(tmp, struct file_lock, fl_link);
inode = fl->fl_file->f_dentry->d_inode;
if (inode->i_sb->s_magic != NFS_SUPER_MAGIC)
continue;
if (fl->fl_u.nfs_fl.owner->host != host)
continue;
if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM))
continue;
fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM;
nlmclnt_reclaim(host, fl);
if (signalled())
break;
goto restart;
}
host->h_reclaiming = 0;
/* Now, wake up all processes that sleep on a blocked lock */
list_for_each_entry(block, &nlm_blocked, b_list) {
if (block->b_host == host) {
block->b_status = NLM_LCK_DENIED_GRACE_PERIOD;
wake_up(&block->b_wait);
}
}
/* Release host handle after use */
nlm_release_host(host);
lockd_down();
unlock_kernel();
module_put_and_exit(0);
}
|
