2 * linux/fs/lockd/clntlock.c
4 * Lock handling for the client side NLM implementation
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/time.h>
12 #include <linux/nfs_fs.h>
13 #include <linux/sunrpc/clnt.h>
14 #include <linux/sunrpc/svc.h>
15 #include <linux/lockd/lockd.h>
16 #include <linux/smp_lock.h>
18 #define NLMDBG_FACILITY NLMDBG_CLIENT
21 * Local function prototypes
23 static int reclaimer(void *ptr
);
26 * The following functions handle blocking and granting from the
31 * This is the representation of a blocked client lock.
34 struct list_head b_list
; /* linked list */
35 wait_queue_head_t b_wait
; /* where to wait on */
36 struct nlm_host
* b_host
;
37 struct file_lock
* b_lock
; /* local file lock */
38 unsigned short b_reclaim
; /* got to reclaim lock */
39 u32 b_status
; /* grant callback status */
42 static LIST_HEAD(nlm_blocked
);
45 * Queue up a lock for blocking so that the GRANTED request can see it
47 struct nlm_wait
*nlmclnt_prepare_block(struct nlm_host
*host
, struct file_lock
*fl
)
49 struct nlm_wait
*block
;
51 block
= kmalloc(sizeof(*block
), GFP_KERNEL
);
55 init_waitqueue_head(&block
->b_wait
);
56 block
->b_status
= NLM_LCK_BLOCKED
;
57 list_add(&block
->b_list
, &nlm_blocked
);
62 void nlmclnt_finish_block(struct nlm_wait
*block
)
66 list_del(&block
->b_list
);
73 int nlmclnt_block(struct nlm_wait
*block
, struct nlm_rqst
*req
, long timeout
)
77 /* A borken server might ask us to block even if we didn't
78 * request it. Just say no!
83 /* Go to sleep waiting for GRANT callback. Some servers seem
84 * to lose callbacks, however, so we're going to poll from
85 * time to time just to make sure.
87 * For now, the retry frequency is pretty high; normally
88 * a 1 minute timeout would do. See the comment before
89 * nlmclnt_lock for an explanation.
91 ret
= wait_event_interruptible_timeout(block
->b_wait
,
92 block
->b_status
!= NLM_LCK_BLOCKED
,
96 req
->a_res
.status
= block
->b_status
;
101 * The server lockd has called us back to tell us the lock was granted
103 u32
nlmclnt_grant(const struct sockaddr_in
*addr
, const struct nlm_lock
*lock
)
105 const struct file_lock
*fl
= &lock
->fl
;
106 const struct nfs_fh
*fh
= &lock
->fh
;
107 struct nlm_wait
*block
;
108 u32 res
= nlm_lck_denied
;
111 * Look up blocked request based on arguments.
112 * Warning: must not use cookie to match it!
114 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
115 struct file_lock
*fl_blocked
= block
->b_lock
;
117 if (fl_blocked
->fl_start
!= fl
->fl_start
)
119 if (fl_blocked
->fl_end
!= fl
->fl_end
)
122 * Careful! The NLM server will return the 32-bit "pid" that
123 * we put on the wire: in this case the lockowner "pid".
125 if (fl_blocked
->fl_u
.nfs_fl
.owner
->pid
!= lock
->svid
)
127 if (!nlm_cmp_addr(&block
->b_host
->h_addr
, addr
))
129 if (nfs_compare_fh(NFS_FH(fl_blocked
->fl_file
->f_dentry
->d_inode
) ,fh
) != 0)
131 /* Alright, we found a lock. Set the return status
132 * and wake up the caller
134 block
->b_status
= NLM_LCK_GRANTED
;
135 wake_up(&block
->b_wait
);
142 * The following procedures deal with the recovery of locks after a
147 * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number,
148 * that we mark locks for reclaiming, and that we bump the pseudo NSM state.
150 static void nlmclnt_prepare_reclaim(struct nlm_host
*host
)
152 down_write(&host
->h_rwsem
);
153 if (host
->h_nsmhandle
)
154 host
->h_nsmhandle
->sm_monitored
= 0;
156 host
->h_nextrebind
= 0;
157 nlm_rebind_host(host
);
160 * Mark the locks for reclaiming.
162 list_splice_init(&host
->h_granted
, &host
->h_reclaim
);
164 dprintk("NLM: reclaiming locks for host %s\n", host
->h_name
);
167 static void nlmclnt_finish_reclaim(struct nlm_host
*host
)
169 host
->h_reclaiming
= 0;
170 up_write(&host
->h_rwsem
);
171 dprintk("NLM: done reclaiming locks for host %s", host
->h_name
);
175 * Reclaim all locks on server host. We do this by spawning a separate
179 nlmclnt_recovery(struct nlm_host
*host
, u32 newstate
)
181 if (host
->h_nsmstate
== newstate
)
183 host
->h_nsmstate
= newstate
;
184 if (!host
->h_reclaiming
++) {
186 __module_get(THIS_MODULE
);
187 if (kernel_thread(reclaimer
, host
, CLONE_KERNEL
) < 0)
188 module_put(THIS_MODULE
);
195 struct nlm_host
*host
= (struct nlm_host
*) ptr
;
196 struct nlm_wait
*block
;
197 struct file_lock
*fl
, *next
;
200 daemonize("%s-reclaim", host
->h_name
);
201 allow_signal(SIGKILL
);
203 /* This one ensures that our parent doesn't terminate while the
204 * reclaim is in progress */
206 lockd_up(0); /* note: this cannot fail as lockd is already running */
208 nlmclnt_prepare_reclaim(host
);
209 /* First, reclaim all locks that have been marked. */
211 nsmstate
= host
->h_nsmstate
;
212 list_for_each_entry_safe(fl
, next
, &host
->h_reclaim
, fl_u
.nfs_fl
.list
) {
213 list_del_init(&fl
->fl_u
.nfs_fl
.list
);
217 if (nlmclnt_reclaim(host
, fl
) != 0)
219 list_add_tail(&fl
->fl_u
.nfs_fl
.list
, &host
->h_granted
);
220 if (host
->h_nsmstate
!= nsmstate
) {
221 /* Argh! The server rebooted again! */
222 list_splice_init(&host
->h_granted
, &host
->h_reclaim
);
226 nlmclnt_finish_reclaim(host
);
228 /* Now, wake up all processes that sleep on a blocked lock */
229 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
230 if (block
->b_host
== host
) {
231 block
->b_status
= NLM_LCK_DENIED_GRACE_PERIOD
;
232 wake_up(&block
->b_wait
);
236 /* Release host handle after use */
237 nlm_release_host(host
);
240 module_put_and_exit(0);