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1/*
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/slab.h>
12#include <linux/time.h>
13#include <linux/nfs_fs.h>
14#include <linux/sunrpc/clnt.h>
15#include <linux/sunrpc/svc.h>
16#include <linux/lockd/lockd.h>
17#include <linux/kthread.h>
18
19#define NLMDBG_FACILITY NLMDBG_CLIENT
20
21/*
22 * Local function prototypes
23 */
24static int reclaimer(void *ptr);
25
26/*
27 * The following functions handle blocking and granting from the
28 * client perspective.
29 */
30
31/*
32 * This is the representation of a blocked client lock.
33 */
34struct nlm_wait {
35 struct list_head b_list; /* linked list */
36 wait_queue_head_t b_wait; /* where to wait on */
37 struct nlm_host * b_host;
38 struct file_lock * b_lock; /* local file lock */
39 unsigned short b_reclaim; /* got to reclaim lock */
40 __be32 b_status; /* grant callback status */
41};
42
43static LIST_HEAD(nlm_blocked);
44static DEFINE_SPINLOCK(nlm_blocked_lock);
45
46/**
47 * nlmclnt_init - Set up per-NFS mount point lockd data structures
48 * @nlm_init: pointer to arguments structure
49 *
50 * Returns pointer to an appropriate nlm_host struct,
51 * or an ERR_PTR value.
52 */
53struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
54{
55 struct nlm_host *host;
56 u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
57 int status;
58
59 status = lockd_up();
60 if (status < 0)
61 return ERR_PTR(status);
62
63 host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
64 nlm_init->protocol, nlm_version,
65 nlm_init->hostname, nlm_init->noresvport);
66 if (host == NULL) {
67 lockd_down();
68 return ERR_PTR(-ENOLCK);
69 }
70
71 return host;
72}
73EXPORT_SYMBOL_GPL(nlmclnt_init);
74
75/**
76 * nlmclnt_done - Release resources allocated by nlmclnt_init()
77 * @host: nlm_host structure reserved by nlmclnt_init()
78 *
79 */
80void nlmclnt_done(struct nlm_host *host)
81{
82 nlmclnt_release_host(host);
83 lockd_down();
84}
85EXPORT_SYMBOL_GPL(nlmclnt_done);
86
87/*
88 * Queue up a lock for blocking so that the GRANTED request can see it
89 */
90struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
91{
92 struct nlm_wait *block;
93
94 block = kmalloc(sizeof(*block), GFP_KERNEL);
95 if (block != NULL) {
96 block->b_host = host;
97 block->b_lock = fl;
98 init_waitqueue_head(&block->b_wait);
99 block->b_status = nlm_lck_blocked;
100
101 spin_lock(&nlm_blocked_lock);
102 list_add(&block->b_list, &nlm_blocked);
103 spin_unlock(&nlm_blocked_lock);
104 }
105 return block;
106}
107
108void nlmclnt_finish_block(struct nlm_wait *block)
109{
110 if (block == NULL)
111 return;
112 spin_lock(&nlm_blocked_lock);
113 list_del(&block->b_list);
114 spin_unlock(&nlm_blocked_lock);
115 kfree(block);
116}
117
118/*
119 * Block on a lock
120 */
121int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
122{
123 long ret;
124
125 /* A borken server might ask us to block even if we didn't
126 * request it. Just say no!
127 */
128 if (block == NULL)
129 return -EAGAIN;
130
131 /* Go to sleep waiting for GRANT callback. Some servers seem
132 * to lose callbacks, however, so we're going to poll from
133 * time to time just to make sure.
134 *
135 * For now, the retry frequency is pretty high; normally
136 * a 1 minute timeout would do. See the comment before
137 * nlmclnt_lock for an explanation.
138 */
139 ret = wait_event_interruptible_timeout(block->b_wait,
140 block->b_status != nlm_lck_blocked,
141 timeout);
142 if (ret < 0)
143 return -ERESTARTSYS;
144 req->a_res.status = block->b_status;
145 return 0;
146}
147
148/*
149 * The server lockd has called us back to tell us the lock was granted
150 */
151__be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
152{
153 const struct file_lock *fl = &lock->fl;
154 const struct nfs_fh *fh = &lock->fh;
155 struct nlm_wait *block;
156 __be32 res = nlm_lck_denied;
157
158 /*
159 * Look up blocked request based on arguments.
160 * Warning: must not use cookie to match it!
161 */
162 spin_lock(&nlm_blocked_lock);
163 list_for_each_entry(block, &nlm_blocked, b_list) {
164 struct file_lock *fl_blocked = block->b_lock;
165
166 if (fl_blocked->fl_start != fl->fl_start)
167 continue;
168 if (fl_blocked->fl_end != fl->fl_end)
169 continue;
170 /*
171 * Careful! The NLM server will return the 32-bit "pid" that
172 * we put on the wire: in this case the lockowner "pid".
173 */
174 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
175 continue;
176 if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
177 continue;
178 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0)
179 continue;
180 /* Alright, we found a lock. Set the return status
181 * and wake up the caller
182 */
183 block->b_status = nlm_granted;
184 wake_up(&block->b_wait);
185 res = nlm_granted;
186 }
187 spin_unlock(&nlm_blocked_lock);
188 return res;
189}
190
191/*
192 * The following procedures deal with the recovery of locks after a
193 * server crash.
194 */
195
196/*
197 * Reclaim all locks on server host. We do this by spawning a separate
198 * reclaimer thread.
199 */
200void
201nlmclnt_recovery(struct nlm_host *host)
202{
203 struct task_struct *task;
204
205 if (!host->h_reclaiming++) {
206 nlm_get_host(host);
207 task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
208 if (IS_ERR(task))
209 printk(KERN_ERR "lockd: unable to spawn reclaimer "
210 "thread. Locks for %s won't be reclaimed! "
211 "(%ld)\n", host->h_name, PTR_ERR(task));
212 }
213}
214
215static int
216reclaimer(void *ptr)
217{
218 struct nlm_host *host = (struct nlm_host *) ptr;
219 struct nlm_wait *block;
220 struct file_lock *fl, *next;
221 u32 nsmstate;
222
223 allow_signal(SIGKILL);
224
225 down_write(&host->h_rwsem);
226 lockd_up(); /* note: this cannot fail as lockd is already running */
227
228 dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
229
230restart:
231 nsmstate = host->h_nsmstate;
232
233 /* Force a portmap getport - the peer's lockd will
234 * most likely end up on a different port.
235 */
236 host->h_nextrebind = jiffies;
237 nlm_rebind_host(host);
238
239 /* First, reclaim all locks that have been granted. */
240 list_splice_init(&host->h_granted, &host->h_reclaim);
241 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
242 list_del_init(&fl->fl_u.nfs_fl.list);
243
244 /*
245 * sending this thread a SIGKILL will result in any unreclaimed
246 * locks being removed from the h_granted list. This means that
247 * the kernel will not attempt to reclaim them again if a new
248 * reclaimer thread is spawned for this host.
249 */
250 if (signalled())
251 continue;
252 if (nlmclnt_reclaim(host, fl) != 0)
253 continue;
254 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
255 if (host->h_nsmstate != nsmstate) {
256 /* Argh! The server rebooted again! */
257 goto restart;
258 }
259 }
260
261 host->h_reclaiming = 0;
262 up_write(&host->h_rwsem);
263 dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
264
265 /* Now, wake up all processes that sleep on a blocked lock */
266 spin_lock(&nlm_blocked_lock);
267 list_for_each_entry(block, &nlm_blocked, b_list) {
268 if (block->b_host == host) {
269 block->b_status = nlm_lck_denied_grace_period;
270 wake_up(&block->b_wait);
271 }
272 }
273 spin_unlock(&nlm_blocked_lock);
274
275 /* Release host handle after use */
276 nlmclnt_release_host(host);
277 lockd_down();
278 return 0;
279}
1/*
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/slab.h>
12#include <linux/time.h>
13#include <linux/nfs_fs.h>
14#include <linux/sunrpc/clnt.h>
15#include <linux/sunrpc/svc.h>
16#include <linux/lockd/lockd.h>
17#include <linux/kthread.h>
18
19#define NLMDBG_FACILITY NLMDBG_CLIENT
20
21/*
22 * Local function prototypes
23 */
24static int reclaimer(void *ptr);
25
26/*
27 * The following functions handle blocking and granting from the
28 * client perspective.
29 */
30
31/*
32 * This is the representation of a blocked client lock.
33 */
34struct nlm_wait {
35 struct list_head b_list; /* linked list */
36 wait_queue_head_t b_wait; /* where to wait on */
37 struct nlm_host * b_host;
38 struct file_lock * b_lock; /* local file lock */
39 unsigned short b_reclaim; /* got to reclaim lock */
40 __be32 b_status; /* grant callback status */
41};
42
43static LIST_HEAD(nlm_blocked);
44static DEFINE_SPINLOCK(nlm_blocked_lock);
45
46/**
47 * nlmclnt_init - Set up per-NFS mount point lockd data structures
48 * @nlm_init: pointer to arguments structure
49 *
50 * Returns pointer to an appropriate nlm_host struct,
51 * or an ERR_PTR value.
52 */
53struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
54{
55 struct nlm_host *host;
56 u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
57 int status;
58
59 status = lockd_up(nlm_init->net);
60 if (status < 0)
61 return ERR_PTR(status);
62
63 host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
64 nlm_init->protocol, nlm_version,
65 nlm_init->hostname, nlm_init->noresvport,
66 nlm_init->net);
67 if (host == NULL) {
68 lockd_down(nlm_init->net);
69 return ERR_PTR(-ENOLCK);
70 }
71
72 return host;
73}
74EXPORT_SYMBOL_GPL(nlmclnt_init);
75
76/**
77 * nlmclnt_done - Release resources allocated by nlmclnt_init()
78 * @host: nlm_host structure reserved by nlmclnt_init()
79 *
80 */
81void nlmclnt_done(struct nlm_host *host)
82{
83 struct net *net = host->net;
84
85 nlmclnt_release_host(host);
86 lockd_down(net);
87}
88EXPORT_SYMBOL_GPL(nlmclnt_done);
89
90/*
91 * Queue up a lock for blocking so that the GRANTED request can see it
92 */
93struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
94{
95 struct nlm_wait *block;
96
97 block = kmalloc(sizeof(*block), GFP_KERNEL);
98 if (block != NULL) {
99 block->b_host = host;
100 block->b_lock = fl;
101 init_waitqueue_head(&block->b_wait);
102 block->b_status = nlm_lck_blocked;
103
104 spin_lock(&nlm_blocked_lock);
105 list_add(&block->b_list, &nlm_blocked);
106 spin_unlock(&nlm_blocked_lock);
107 }
108 return block;
109}
110
111void nlmclnt_finish_block(struct nlm_wait *block)
112{
113 if (block == NULL)
114 return;
115 spin_lock(&nlm_blocked_lock);
116 list_del(&block->b_list);
117 spin_unlock(&nlm_blocked_lock);
118 kfree(block);
119}
120
121/*
122 * Block on a lock
123 */
124int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
125{
126 long ret;
127
128 /* A borken server might ask us to block even if we didn't
129 * request it. Just say no!
130 */
131 if (block == NULL)
132 return -EAGAIN;
133
134 /* Go to sleep waiting for GRANT callback. Some servers seem
135 * to lose callbacks, however, so we're going to poll from
136 * time to time just to make sure.
137 *
138 * For now, the retry frequency is pretty high; normally
139 * a 1 minute timeout would do. See the comment before
140 * nlmclnt_lock for an explanation.
141 */
142 ret = wait_event_interruptible_timeout(block->b_wait,
143 block->b_status != nlm_lck_blocked,
144 timeout);
145 if (ret < 0)
146 return -ERESTARTSYS;
147 req->a_res.status = block->b_status;
148 return 0;
149}
150
151/*
152 * The server lockd has called us back to tell us the lock was granted
153 */
154__be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
155{
156 const struct file_lock *fl = &lock->fl;
157 const struct nfs_fh *fh = &lock->fh;
158 struct nlm_wait *block;
159 __be32 res = nlm_lck_denied;
160
161 /*
162 * Look up blocked request based on arguments.
163 * Warning: must not use cookie to match it!
164 */
165 spin_lock(&nlm_blocked_lock);
166 list_for_each_entry(block, &nlm_blocked, b_list) {
167 struct file_lock *fl_blocked = block->b_lock;
168
169 if (fl_blocked->fl_start != fl->fl_start)
170 continue;
171 if (fl_blocked->fl_end != fl->fl_end)
172 continue;
173 /*
174 * Careful! The NLM server will return the 32-bit "pid" that
175 * we put on the wire: in this case the lockowner "pid".
176 */
177 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
178 continue;
179 if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
180 continue;
181 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0)
182 continue;
183 /* Alright, we found a lock. Set the return status
184 * and wake up the caller
185 */
186 block->b_status = nlm_granted;
187 wake_up(&block->b_wait);
188 res = nlm_granted;
189 }
190 spin_unlock(&nlm_blocked_lock);
191 return res;
192}
193
194/*
195 * The following procedures deal with the recovery of locks after a
196 * server crash.
197 */
198
199/*
200 * Reclaim all locks on server host. We do this by spawning a separate
201 * reclaimer thread.
202 */
203void
204nlmclnt_recovery(struct nlm_host *host)
205{
206 struct task_struct *task;
207
208 if (!host->h_reclaiming++) {
209 nlm_get_host(host);
210 task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
211 if (IS_ERR(task))
212 printk(KERN_ERR "lockd: unable to spawn reclaimer "
213 "thread. Locks for %s won't be reclaimed! "
214 "(%ld)\n", host->h_name, PTR_ERR(task));
215 }
216}
217
218static int
219reclaimer(void *ptr)
220{
221 struct nlm_host *host = (struct nlm_host *) ptr;
222 struct nlm_wait *block;
223 struct file_lock *fl, *next;
224 u32 nsmstate;
225 struct net *net = host->net;
226
227 allow_signal(SIGKILL);
228
229 down_write(&host->h_rwsem);
230 lockd_up(net); /* note: this cannot fail as lockd is already running */
231
232 dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
233
234restart:
235 nsmstate = host->h_nsmstate;
236
237 /* Force a portmap getport - the peer's lockd will
238 * most likely end up on a different port.
239 */
240 host->h_nextrebind = jiffies;
241 nlm_rebind_host(host);
242
243 /* First, reclaim all locks that have been granted. */
244 list_splice_init(&host->h_granted, &host->h_reclaim);
245 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
246 list_del_init(&fl->fl_u.nfs_fl.list);
247
248 /*
249 * sending this thread a SIGKILL will result in any unreclaimed
250 * locks being removed from the h_granted list. This means that
251 * the kernel will not attempt to reclaim them again if a new
252 * reclaimer thread is spawned for this host.
253 */
254 if (signalled())
255 continue;
256 if (nlmclnt_reclaim(host, fl) != 0)
257 continue;
258 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
259 if (host->h_nsmstate != nsmstate) {
260 /* Argh! The server rebooted again! */
261 goto restart;
262 }
263 }
264
265 host->h_reclaiming = 0;
266 up_write(&host->h_rwsem);
267 dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
268
269 /* Now, wake up all processes that sleep on a blocked lock */
270 spin_lock(&nlm_blocked_lock);
271 list_for_each_entry(block, &nlm_blocked, b_list) {
272 if (block->b_host == host) {
273 block->b_status = nlm_lck_denied_grace_period;
274 wake_up(&block->b_wait);
275 }
276 }
277 spin_unlock(&nlm_blocked_lock);
278
279 /* Release host handle after use */
280 nlmclnt_release_host(host);
281 lockd_down(net);
282 return 0;
283}