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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 */
Al Viroe8c5c042006-12-13 00:35:03 -080039 __be32 b_status; /* grant callback status */
Linus Torvalds1da177e2005-04-16 15:20:36 -070040};
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);
Al Viroe8c5c042006-12-13 00:35:03 -080056 block->b_status = nlm_lck_blocked;
Trond Myklebust3a649b82006-03-20 13:44:44 -050057 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,
Al Viroe8c5c042006-12-13 00:35:03 -080092 block->b_status != nlm_lck_blocked,
Trond Myklebustecdbf762005-06-22 17:16:31 +000093 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 */
Al Viro52921e02006-10-19 23:28:46 -0700103__be32 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;
Al Viro52921e02006-10-19 23:28:46 -0700108 __be32 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;
Josef Sipek225a7192006-12-08 02:37:18 -0800129 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0)
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800130 continue;
131 /* Alright, we found a lock. Set the return status
132 * and wake up the caller
133 */
Al Viroe8c5c042006-12-13 00:35:03 -0800134 block->b_status = nlm_granted;
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800135 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 * Reclaim all locks on server host. We do this by spawning a separate
148 * reclaimer thread.
149 */
150void
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700151nlmclnt_recovery(struct nlm_host *host)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152{
Trond Myklebust28df9552006-06-09 09:40:27 -0400153 if (!host->h_reclaiming++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 nlm_get_host(host);
155 __module_get(THIS_MODULE);
156 if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
157 module_put(THIS_MODULE);
158 }
159}
160
161static int
162reclaimer(void *ptr)
163{
164 struct nlm_host *host = (struct nlm_host *) ptr;
165 struct nlm_wait *block;
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500166 struct file_lock *fl, *next;
Trond Myklebust28df9552006-06-09 09:40:27 -0400167 u32 nsmstate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
169 daemonize("%s-reclaim", host->h_name);
170 allow_signal(SIGKILL);
171
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700172 down_write(&host->h_rwsem);
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 /* This one ensures that our parent doesn't terminate while the
175 * reclaim is in progress */
176 lock_kernel();
NeilBrown4a3ae422006-10-02 02:17:53 -0700177 lockd_up(0); /* note: this cannot fail as lockd is already running */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
Adrian Bunkd019bcf2007-01-29 13:19:51 -0800179 dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700180
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181restart:
Trond Myklebust28df9552006-06-09 09:40:27 -0400182 nsmstate = host->h_nsmstate;
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700183
184 /* Force a portmap getport - the peer's lockd will
185 * most likely end up on a different port.
186 */
Olaf Kirch0ade0602006-10-04 02:16:04 -0700187 host->h_nextrebind = jiffies;
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700188 nlm_rebind_host(host);
189
190 /* First, reclaim all locks that have been granted. */
191 list_splice_init(&host->h_granted, &host->h_reclaim);
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500192 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
Trond Myklebust4c060b52006-03-20 13:44:41 -0500193 list_del_init(&fl->fl_u.nfs_fl.list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700195 /* Why are we leaking memory here? --okir */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 if (signalled())
Trond Myklebust4c060b52006-03-20 13:44:41 -0500197 continue;
Trond Myklebust28df9552006-06-09 09:40:27 -0400198 if (nlmclnt_reclaim(host, fl) != 0)
199 continue;
200 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
201 if (host->h_nsmstate != nsmstate) {
202 /* Argh! The server rebooted again! */
Trond Myklebust28df9552006-06-09 09:40:27 -0400203 goto restart;
204 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 }
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700206
207 host->h_reclaiming = 0;
208 up_write(&host->h_rwsem);
Adrian Bunkd019bcf2007-01-29 13:19:51 -0800209 dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211 /* Now, wake up all processes that sleep on a blocked lock */
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000212 list_for_each_entry(block, &nlm_blocked, b_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 if (block->b_host == host) {
Al Viroe8c5c042006-12-13 00:35:03 -0800214 block->b_status = nlm_lck_denied_grace_period;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 wake_up(&block->b_wait);
216 }
217 }
218
219 /* Release host handle after use */
220 nlm_release_host(host);
221 lockd_down();
222 unlock_kernel();
223 module_put_and_exit(0);
224}