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Commit | Line | Data |
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1da177e4 LT |
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> | |
5a0e3ad6 | 11 | #include <linux/slab.h> |
1da177e4 LT |
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> | |
df94f000 | 17 | #include <linux/kthread.h> |
1da177e4 LT |
18 | |
19 | #define NLMDBG_FACILITY NLMDBG_CLIENT | |
20 | ||
21 | /* | |
22 | * Local function prototypes | |
23 | */ | |
24 | static 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 | */ | |
34 | struct nlm_wait { | |
4f15e2b1 | 35 | struct list_head b_list; /* linked list */ |
1da177e4 LT |
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 */ | |
e8c5c045 | 40 | __be32 b_status; /* grant callback status */ |
1da177e4 LT |
41 | }; |
42 | ||
4f15e2b1 | 43 | static LIST_HEAD(nlm_blocked); |
63185942 | 44 | static DEFINE_SPINLOCK(nlm_blocked_lock); |
1da177e4 | 45 | |
52c4044d CL |
46 | /** |
47 | * nlmclnt_init - Set up per-NFS mount point lockd data structures | |
883bb163 | 48 | * @nlm_init: pointer to arguments structure |
52c4044d CL |
49 | * |
50 | * Returns pointer to an appropriate nlm_host struct, | |
51 | * or an ERR_PTR value. | |
52 | */ | |
883bb163 | 53 | struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init) |
52c4044d CL |
54 | { |
55 | struct nlm_host *host; | |
883bb163 | 56 | u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4; |
52c4044d CL |
57 | int status; |
58 | ||
26a41409 | 59 | status = lockd_up(); |
52c4044d CL |
60 | if (status < 0) |
61 | return ERR_PTR(status); | |
62 | ||
d7d20440 | 63 | host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen, |
883bb163 | 64 | nlm_init->protocol, nlm_version, |
0cb2659b | 65 | nlm_init->hostname, nlm_init->noresvport); |
52c4044d CL |
66 | if (host == NULL) { |
67 | lockd_down(); | |
68 | return ERR_PTR(-ENOLCK); | |
69 | } | |
70 | ||
71 | return host; | |
72 | } | |
73 | EXPORT_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 | */ | |
80 | void nlmclnt_done(struct nlm_host *host) | |
81 | { | |
8ea6ecc8 | 82 | nlmclnt_release_host(host); |
52c4044d CL |
83 | lockd_down(); |
84 | } | |
85 | EXPORT_SYMBOL_GPL(nlmclnt_done); | |
86 | ||
1da177e4 | 87 | /* |
ecdbf769 | 88 | * Queue up a lock for blocking so that the GRANTED request can see it |
1da177e4 | 89 | */ |
3a649b88 | 90 | struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl) |
ecdbf769 TM |
91 | { |
92 | struct nlm_wait *block; | |
93 | ||
ecdbf769 | 94 | block = kmalloc(sizeof(*block), GFP_KERNEL); |
3a649b88 TM |
95 | if (block != NULL) { |
96 | block->b_host = host; | |
97 | block->b_lock = fl; | |
98 | init_waitqueue_head(&block->b_wait); | |
e8c5c045 | 99 | block->b_status = nlm_lck_blocked; |
63185942 BS |
100 | |
101 | spin_lock(&nlm_blocked_lock); | |
3a649b88 | 102 | list_add(&block->b_list, &nlm_blocked); |
63185942 | 103 | spin_unlock(&nlm_blocked_lock); |
3a649b88 TM |
104 | } |
105 | return block; | |
ecdbf769 TM |
106 | } |
107 | ||
3a649b88 | 108 | void nlmclnt_finish_block(struct nlm_wait *block) |
1da177e4 | 109 | { |
ecdbf769 TM |
110 | if (block == NULL) |
111 | return; | |
63185942 | 112 | spin_lock(&nlm_blocked_lock); |
ecdbf769 | 113 | list_del(&block->b_list); |
63185942 | 114 | spin_unlock(&nlm_blocked_lock); |
ecdbf769 TM |
115 | kfree(block); |
116 | } | |
1da177e4 | 117 | |
ecdbf769 TM |
118 | /* |
119 | * Block on a lock | |
120 | */ | |
3a649b88 | 121 | int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout) |
ecdbf769 | 122 | { |
ecdbf769 | 123 | long ret; |
1da177e4 | 124 | |
ecdbf769 TM |
125 | /* A borken server might ask us to block even if we didn't |
126 | * request it. Just say no! | |
127 | */ | |
3a649b88 | 128 | if (block == NULL) |
ecdbf769 | 129 | return -EAGAIN; |
1da177e4 LT |
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 | */ | |
ecdbf769 | 139 | ret = wait_event_interruptible_timeout(block->b_wait, |
e8c5c045 | 140 | block->b_status != nlm_lck_blocked, |
ecdbf769 | 141 | timeout); |
3a649b88 TM |
142 | if (ret < 0) |
143 | return -ERESTARTSYS; | |
144 | req->a_res.status = block->b_status; | |
145 | return 0; | |
1da177e4 LT |
146 | } |
147 | ||
148 | /* | |
149 | * The server lockd has called us back to tell us the lock was granted | |
150 | */ | |
dcff09f1 | 151 | __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) |
1da177e4 | 152 | { |
5ac5f9d1 TM |
153 | const struct file_lock *fl = &lock->fl; |
154 | const struct nfs_fh *fh = &lock->fh; | |
1da177e4 | 155 | struct nlm_wait *block; |
52921e02 | 156 | __be32 res = nlm_lck_denied; |
1da177e4 LT |
157 | |
158 | /* | |
159 | * Look up blocked request based on arguments. | |
160 | * Warning: must not use cookie to match it! | |
161 | */ | |
63185942 | 162 | spin_lock(&nlm_blocked_lock); |
4f15e2b1 | 163 | list_for_each_entry(block, &nlm_blocked, b_list) { |
5ac5f9d1 TM |
164 | struct file_lock *fl_blocked = block->b_lock; |
165 | ||
7bab377f TM |
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) | |
5ac5f9d1 | 175 | continue; |
4516fc04 | 176 | if (!rpc_cmp_addr(nlm_addr(block->b_host), addr)) |
5ac5f9d1 | 177 | continue; |
225a719f | 178 | if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0) |
5ac5f9d1 TM |
179 | continue; |
180 | /* Alright, we found a lock. Set the return status | |
181 | * and wake up the caller | |
182 | */ | |
e8c5c045 | 183 | block->b_status = nlm_granted; |
5ac5f9d1 TM |
184 | wake_up(&block->b_wait); |
185 | res = nlm_granted; | |
1da177e4 | 186 | } |
63185942 | 187 | spin_unlock(&nlm_blocked_lock); |
ecdbf769 | 188 | return res; |
1da177e4 LT |
189 | } |
190 | ||
191 | /* | |
192 | * The following procedures deal with the recovery of locks after a | |
193 | * server crash. | |
194 | */ | |
195 | ||
1da177e4 LT |
196 | /* |
197 | * Reclaim all locks on server host. We do this by spawning a separate | |
198 | * reclaimer thread. | |
199 | */ | |
200 | void | |
5c8dd29c | 201 | nlmclnt_recovery(struct nlm_host *host) |
1da177e4 | 202 | { |
df94f000 JL |
203 | struct task_struct *task; |
204 | ||
28df955a | 205 | if (!host->h_reclaiming++) { |
1da177e4 | 206 | nlm_get_host(host); |
df94f000 JL |
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)); | |
1da177e4 LT |
212 | } |
213 | } | |
214 | ||
215 | static int | |
216 | reclaimer(void *ptr) | |
217 | { | |
218 | struct nlm_host *host = (struct nlm_host *) ptr; | |
219 | struct nlm_wait *block; | |
26bcbf96 | 220 | struct file_lock *fl, *next; |
28df955a | 221 | u32 nsmstate; |
1da177e4 | 222 | |
1da177e4 LT |
223 | allow_signal(SIGKILL); |
224 | ||
5c8dd29c | 225 | down_write(&host->h_rwsem); |
26a41409 | 226 | lockd_up(); /* note: this cannot fail as lockd is already running */ |
1da177e4 | 227 | |
d019bcf0 | 228 | dprintk("lockd: reclaiming locks for host %s\n", host->h_name); |
5c8dd29c | 229 | |
1da177e4 | 230 | restart: |
28df955a | 231 | nsmstate = host->h_nsmstate; |
5c8dd29c OK |
232 | |
233 | /* Force a portmap getport - the peer's lockd will | |
234 | * most likely end up on a different port. | |
235 | */ | |
0ade060e | 236 | host->h_nextrebind = jiffies; |
5c8dd29c OK |
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); | |
26bcbf96 | 241 | list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) { |
4c060b53 | 242 | list_del_init(&fl->fl_u.nfs_fl.list); |
1da177e4 | 243 | |
df94f000 JL |
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 | */ | |
1da177e4 | 250 | if (signalled()) |
4c060b53 | 251 | continue; |
28df955a TM |
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! */ | |
28df955a TM |
257 | goto restart; |
258 | } | |
1da177e4 | 259 | } |
5c8dd29c OK |
260 | |
261 | host->h_reclaiming = 0; | |
262 | up_write(&host->h_rwsem); | |
d019bcf0 | 263 | dprintk("NLM: done reclaiming locks for host %s\n", host->h_name); |
1da177e4 LT |
264 | |
265 | /* Now, wake up all processes that sleep on a blocked lock */ | |
63185942 | 266 | spin_lock(&nlm_blocked_lock); |
4f15e2b1 | 267 | list_for_each_entry(block, &nlm_blocked, b_list) { |
1da177e4 | 268 | if (block->b_host == host) { |
e8c5c045 | 269 | block->b_status = nlm_lck_denied_grace_period; |
1da177e4 LT |
270 | wake_up(&block->b_wait); |
271 | } | |
272 | } | |
63185942 | 273 | spin_unlock(&nlm_blocked_lock); |
1da177e4 LT |
274 | |
275 | /* Release host handle after use */ | |
8ea6ecc8 | 276 | nlmclnt_release_host(host); |
1da177e4 | 277 | lockd_down(); |
df94f000 | 278 | return 0; |
1da177e4 | 279 | } |