blob: 52774feab93f3c4736febeeca2146a7dad2b9dfc [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/lockd/clntlock.c
3 *
4 * Lock handling for the client side NLM implementation
5 *
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7 */
8
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>
17
18#define NLMDBG_FACILITY NLMDBG_CLIENT
19
20/*
21 * Local function prototypes
22 */
23static int reclaimer(void *ptr);
24
25/*
26 * The following functions handle blocking and granting from the
27 * client perspective.
28 */
29
30/*
31 * This is the representation of a blocked client lock.
32 */
33struct nlm_wait {
Trond Myklebust4f15e2b2005-06-22 17:16:31 +000034 struct list_head b_list; /* linked list */
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 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 */
40};
41
Trond Myklebust4f15e2b2005-06-22 17:16:31 +000042static LIST_HEAD(nlm_blocked);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44/*
Trond Myklebustecdbf762005-06-22 17:16:31 +000045 * Queue up a lock for blocking so that the GRANTED request can see it
46 */
Trond Myklebust3a649b82006-03-20 13:44:44 -050047struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
Trond Myklebustecdbf762005-06-22 17:16:31 +000048{
49 struct nlm_wait *block;
50
Trond Myklebustecdbf762005-06-22 17:16:31 +000051 block = kmalloc(sizeof(*block), GFP_KERNEL);
Trond Myklebust3a649b82006-03-20 13:44:44 -050052 if (block != NULL) {
53 block->b_host = host;
54 block->b_lock = fl;
55 init_waitqueue_head(&block->b_wait);
56 block->b_status = NLM_LCK_BLOCKED;
57 list_add(&block->b_list, &nlm_blocked);
58 }
59 return block;
Trond Myklebustecdbf762005-06-22 17:16:31 +000060}
61
Trond Myklebust3a649b82006-03-20 13:44:44 -050062void nlmclnt_finish_block(struct nlm_wait *block)
Trond Myklebustecdbf762005-06-22 17:16:31 +000063{
Trond Myklebustecdbf762005-06-22 17:16:31 +000064 if (block == NULL)
65 return;
Trond Myklebustecdbf762005-06-22 17:16:31 +000066 list_del(&block->b_list);
67 kfree(block);
68}
69
70/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 * Block on a lock
72 */
Trond Myklebust3a649b82006-03-20 13:44:44 -050073int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074{
Trond Myklebustecdbf762005-06-22 17:16:31 +000075 long ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Trond Myklebustecdbf762005-06-22 17:16:31 +000077 /* A borken server might ask us to block even if we didn't
78 * request it. Just say no!
79 */
Trond Myklebust3a649b82006-03-20 13:44:44 -050080 if (block == NULL)
Trond Myklebustecdbf762005-06-22 17:16:31 +000081 return -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
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.
86 *
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.
90 */
Trond Myklebustecdbf762005-06-22 17:16:31 +000091 ret = wait_event_interruptible_timeout(block->b_wait,
92 block->b_status != NLM_LCK_BLOCKED,
93 timeout);
Trond Myklebust3a649b82006-03-20 13:44:44 -050094 if (ret < 0)
95 return -ERESTARTSYS;
96 req->a_res.status = block->b_status;
97 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098}
99
100/*
101 * The server lockd has called us back to tell us the lock was granted
102 */
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800103u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800105 const struct file_lock *fl = &lock->fl;
106 const struct nfs_fh *fh = &lock->fh;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 struct nlm_wait *block;
Trond Myklebustecdbf762005-06-22 17:16:31 +0000108 u32 res = nlm_lck_denied;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109
110 /*
111 * Look up blocked request based on arguments.
112 * Warning: must not use cookie to match it!
113 */
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000114 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800115 struct file_lock *fl_blocked = block->b_lock;
116
Trond Myklebust7bab3772006-03-20 13:44:06 -0500117 if (fl_blocked->fl_start != fl->fl_start)
118 continue;
119 if (fl_blocked->fl_end != fl->fl_end)
120 continue;
121 /*
122 * Careful! The NLM server will return the 32-bit "pid" that
123 * we put on the wire: in this case the lockowner "pid".
124 */
125 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800126 continue;
127 if (!nlm_cmp_addr(&block->b_host->h_addr, addr))
128 continue;
129 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_dentry->d_inode) ,fh) != 0)
130 continue;
131 /* Alright, we found a lock. Set the return status
132 * and wake up the caller
133 */
134 block->b_status = NLM_LCK_GRANTED;
135 wake_up(&block->b_wait);
136 res = nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 }
Trond Myklebustecdbf762005-06-22 17:16:31 +0000138 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
140
141/*
142 * The following procedures deal with the recovery of locks after a
143 * server crash.
144 */
145
146/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 * 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.
149 */
Trond Myklebust28df9552006-06-09 09:40:27 -0400150static void nlmclnt_prepare_reclaim(struct nlm_host *host)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151{
Trond Myklebust28df9552006-06-09 09:40:27 -0400152 down_write(&host->h_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 host->h_monitored = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 host->h_state++;
155 host->h_nextrebind = 0;
156 nlm_rebind_host(host);
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500157
158 /*
159 * Mark the locks for reclaiming.
160 */
161 list_splice_init(&host->h_granted, &host->h_reclaim);
162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 dprintk("NLM: reclaiming locks for host %s", host->h_name);
164}
165
Trond Myklebust28df9552006-06-09 09:40:27 -0400166static void nlmclnt_finish_reclaim(struct nlm_host *host)
167{
168 host->h_reclaiming = 0;
169 up_write(&host->h_rwsem);
170 dprintk("NLM: done reclaiming locks for host %s", host->h_name);
171}
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173/*
174 * Reclaim all locks on server host. We do this by spawning a separate
175 * reclaimer thread.
176 */
177void
178nlmclnt_recovery(struct nlm_host *host, u32 newstate)
179{
Trond Myklebust28df9552006-06-09 09:40:27 -0400180 if (host->h_nsmstate == newstate)
181 return;
182 host->h_nsmstate = newstate;
183 if (!host->h_reclaiming++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 nlm_get_host(host);
185 __module_get(THIS_MODULE);
186 if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
187 module_put(THIS_MODULE);
188 }
189}
190
191static int
192reclaimer(void *ptr)
193{
194 struct nlm_host *host = (struct nlm_host *) ptr;
195 struct nlm_wait *block;
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500196 struct file_lock *fl, *next;
Trond Myklebust28df9552006-06-09 09:40:27 -0400197 u32 nsmstate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
199 daemonize("%s-reclaim", host->h_name);
200 allow_signal(SIGKILL);
201
202 /* This one ensures that our parent doesn't terminate while the
203 * reclaim is in progress */
204 lock_kernel();
205 lockd_up();
206
Trond Myklebust28df9552006-06-09 09:40:27 -0400207 nlmclnt_prepare_reclaim(host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 /* First, reclaim all locks that have been marked. */
209restart:
Trond Myklebust28df9552006-06-09 09:40:27 -0400210 nsmstate = host->h_nsmstate;
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500211 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
Trond Myklebust4c060b52006-03-20 13:44:41 -0500212 list_del_init(&fl->fl_u.nfs_fl.list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 if (signalled())
Trond Myklebust4c060b52006-03-20 13:44:41 -0500215 continue;
Trond Myklebust28df9552006-06-09 09:40:27 -0400216 if (nlmclnt_reclaim(host, fl) != 0)
217 continue;
218 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
219 if (host->h_nsmstate != nsmstate) {
220 /* Argh! The server rebooted again! */
221 list_splice_init(&host->h_granted, &host->h_reclaim);
222 goto restart;
223 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 }
Trond Myklebust28df9552006-06-09 09:40:27 -0400225 nlmclnt_finish_reclaim(host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227 /* Now, wake up all processes that sleep on a blocked lock */
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000228 list_for_each_entry(block, &nlm_blocked, b_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 if (block->b_host == host) {
230 block->b_status = NLM_LCK_DENIED_GRACE_PERIOD;
231 wake_up(&block->b_wait);
232 }
233 }
234
235 /* Release host handle after use */
236 nlm_release_host(host);
237 lockd_down();
238 unlock_kernel();
239 module_put_and_exit(0);
240}