blob: da6354baa0b804b36d2778282b31bc5ae8e2d858 [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 */
47int nlmclnt_prepare_block(struct nlm_rqst *req, struct nlm_host *host, struct file_lock *fl)
48{
49 struct nlm_wait *block;
50
51 BUG_ON(req->a_block != NULL);
52 block = kmalloc(sizeof(*block), GFP_KERNEL);
53 if (block == NULL)
54 return -ENOMEM;
55 block->b_host = host;
56 block->b_lock = fl;
57 init_waitqueue_head(&block->b_wait);
58 block->b_status = NLM_LCK_BLOCKED;
59
60 list_add(&block->b_list, &nlm_blocked);
61 req->a_block = block;
62
63 return 0;
64}
65
66void nlmclnt_finish_block(struct nlm_rqst *req)
67{
68 struct nlm_wait *block = req->a_block;
69
70 if (block == NULL)
71 return;
72 req->a_block = NULL;
73 list_del(&block->b_list);
74 kfree(block);
75}
76
77/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 * Block on a lock
79 */
Trond Myklebustecdbf762005-06-22 17:16:31 +000080long nlmclnt_block(struct nlm_rqst *req, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -070081{
Trond Myklebustecdbf762005-06-22 17:16:31 +000082 struct nlm_wait *block = req->a_block;
83 long ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Trond Myklebustecdbf762005-06-22 17:16:31 +000085 /* A borken server might ask us to block even if we didn't
86 * request it. Just say no!
87 */
88 if (!req->a_args.block)
89 return -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91 /* Go to sleep waiting for GRANT callback. Some servers seem
92 * to lose callbacks, however, so we're going to poll from
93 * time to time just to make sure.
94 *
95 * For now, the retry frequency is pretty high; normally
96 * a 1 minute timeout would do. See the comment before
97 * nlmclnt_lock for an explanation.
98 */
Trond Myklebustecdbf762005-06-22 17:16:31 +000099 ret = wait_event_interruptible_timeout(block->b_wait,
100 block->b_status != NLM_LCK_BLOCKED,
101 timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
Trond Myklebustecdbf762005-06-22 17:16:31 +0000103 if (block->b_status != NLM_LCK_BLOCKED) {
104 req->a_res.status = block->b_status;
105 block->b_status = NLM_LCK_BLOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 }
107
Trond Myklebustecdbf762005-06-22 17:16:31 +0000108 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109}
110
111/*
112 * The server lockd has called us back to tell us the lock was granted
113 */
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800114u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115{
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800116 const struct file_lock *fl = &lock->fl;
117 const struct nfs_fh *fh = &lock->fh;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 struct nlm_wait *block;
Trond Myklebustecdbf762005-06-22 17:16:31 +0000119 u32 res = nlm_lck_denied;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
121 /*
122 * Look up blocked request based on arguments.
123 * Warning: must not use cookie to match it!
124 */
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000125 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800126 struct file_lock *fl_blocked = block->b_lock;
127
128 if (!nlm_compare_locks(fl_blocked, fl))
129 continue;
130 if (!nlm_cmp_addr(&block->b_host->h_addr, addr))
131 continue;
132 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_dentry->d_inode) ,fh) != 0)
133 continue;
134 /* Alright, we found a lock. Set the return status
135 * and wake up the caller
136 */
137 block->b_status = NLM_LCK_GRANTED;
138 wake_up(&block->b_wait);
139 res = nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 }
Trond Myklebustecdbf762005-06-22 17:16:31 +0000141 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142}
143
144/*
145 * The following procedures deal with the recovery of locks after a
146 * server crash.
147 */
148
149/*
150 * Mark the locks for reclaiming.
151 * FIXME: In 2.5 we don't want to iterate through any global file_lock_list.
152 * Maintain NLM lock reclaiming lists in the nlm_host instead.
153 */
154static
155void nlmclnt_mark_reclaim(struct nlm_host *host)
156{
157 struct file_lock *fl;
158 struct inode *inode;
159 struct list_head *tmp;
160
161 list_for_each(tmp, &file_lock_list) {
162 fl = list_entry(tmp, struct file_lock, fl_link);
163
164 inode = fl->fl_file->f_dentry->d_inode;
165 if (inode->i_sb->s_magic != NFS_SUPER_MAGIC)
166 continue;
Trond Myklebust9b5b1f52005-12-19 17:11:25 -0500167 if (fl->fl_u.nfs_fl.owner == NULL)
168 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 if (fl->fl_u.nfs_fl.owner->host != host)
170 continue;
171 if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_GRANTED))
172 continue;
173 fl->fl_u.nfs_fl.flags |= NFS_LCK_RECLAIM;
174 }
175}
176
177/*
178 * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number,
179 * that we mark locks for reclaiming, and that we bump the pseudo NSM state.
180 */
181static inline
182void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate)
183{
184 host->h_monitored = 0;
185 host->h_nsmstate = newstate;
186 host->h_state++;
187 host->h_nextrebind = 0;
188 nlm_rebind_host(host);
189 nlmclnt_mark_reclaim(host);
190 dprintk("NLM: reclaiming locks for host %s", host->h_name);
191}
192
193/*
194 * Reclaim all locks on server host. We do this by spawning a separate
195 * reclaimer thread.
196 */
197void
198nlmclnt_recovery(struct nlm_host *host, u32 newstate)
199{
200 if (host->h_reclaiming++) {
201 if (host->h_nsmstate == newstate)
202 return;
203 nlmclnt_prepare_reclaim(host, newstate);
204 } else {
205 nlmclnt_prepare_reclaim(host, newstate);
206 nlm_get_host(host);
207 __module_get(THIS_MODULE);
208 if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
209 module_put(THIS_MODULE);
210 }
211}
212
213static int
214reclaimer(void *ptr)
215{
216 struct nlm_host *host = (struct nlm_host *) ptr;
217 struct nlm_wait *block;
218 struct list_head *tmp;
219 struct file_lock *fl;
220 struct inode *inode;
221
222 daemonize("%s-reclaim", host->h_name);
223 allow_signal(SIGKILL);
224
225 /* This one ensures that our parent doesn't terminate while the
226 * reclaim is in progress */
227 lock_kernel();
228 lockd_up();
229
230 /* First, reclaim all locks that have been marked. */
231restart:
232 list_for_each(tmp, &file_lock_list) {
233 fl = list_entry(tmp, struct file_lock, fl_link);
234
235 inode = fl->fl_file->f_dentry->d_inode;
236 if (inode->i_sb->s_magic != NFS_SUPER_MAGIC)
237 continue;
Trond Myklebust9b5b1f52005-12-19 17:11:25 -0500238 if (fl->fl_u.nfs_fl.owner == NULL)
239 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 if (fl->fl_u.nfs_fl.owner->host != host)
241 continue;
242 if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM))
243 continue;
244
245 fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM;
246 nlmclnt_reclaim(host, fl);
247 if (signalled())
248 break;
249 goto restart;
250 }
251
252 host->h_reclaiming = 0;
253
254 /* Now, wake up all processes that sleep on a blocked lock */
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000255 list_for_each_entry(block, &nlm_blocked, b_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 if (block->b_host == host) {
257 block->b_status = NLM_LCK_DENIED_GRACE_PERIOD;
258 wake_up(&block->b_wait);
259 }
260 }
261
262 /* Release host handle after use */
263 nlm_release_host(host);
264 lockd_down();
265 unlock_kernel();
266 module_put_and_exit(0);
267}