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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> | |
17 | #include <linux/smp_lock.h> | |
df94f000 | 18 | #include <linux/kthread.h> |
1da177e4 LT |
19 | |
20 | #define NLMDBG_FACILITY NLMDBG_CLIENT | |
21 | ||
22 | /* | |
23 | * Local function prototypes | |
24 | */ | |
25 | static int reclaimer(void *ptr); | |
26 | ||
27 | /* | |
28 | * The following functions handle blocking and granting from the | |
29 | * client perspective. | |
30 | */ | |
31 | ||
32 | /* | |
33 | * This is the representation of a blocked client lock. | |
34 | */ | |
35 | struct nlm_wait { | |
4f15e2b1 | 36 | struct list_head b_list; /* linked list */ |
1da177e4 LT |
37 | wait_queue_head_t b_wait; /* where to wait on */ |
38 | struct nlm_host * b_host; | |
39 | struct file_lock * b_lock; /* local file lock */ | |
40 | unsigned short b_reclaim; /* got to reclaim lock */ | |
e8c5c045 | 41 | __be32 b_status; /* grant callback status */ |
1da177e4 LT |
42 | }; |
43 | ||
4f15e2b1 | 44 | static LIST_HEAD(nlm_blocked); |
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 | { | |
82 | nlm_release_host(host); | |
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; |
3a649b88 TM |
100 | list_add(&block->b_list, &nlm_blocked); |
101 | } | |
102 | return block; | |
ecdbf769 TM |
103 | } |
104 | ||
3a649b88 | 105 | void nlmclnt_finish_block(struct nlm_wait *block) |
1da177e4 | 106 | { |
ecdbf769 TM |
107 | if (block == NULL) |
108 | return; | |
ecdbf769 TM |
109 | list_del(&block->b_list); |
110 | kfree(block); | |
111 | } | |
1da177e4 | 112 | |
ecdbf769 TM |
113 | /* |
114 | * Block on a lock | |
115 | */ | |
3a649b88 | 116 | int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout) |
ecdbf769 | 117 | { |
ecdbf769 | 118 | long ret; |
1da177e4 | 119 | |
ecdbf769 TM |
120 | /* A borken server might ask us to block even if we didn't |
121 | * request it. Just say no! | |
122 | */ | |
3a649b88 | 123 | if (block == NULL) |
ecdbf769 | 124 | return -EAGAIN; |
1da177e4 LT |
125 | |
126 | /* Go to sleep waiting for GRANT callback. Some servers seem | |
127 | * to lose callbacks, however, so we're going to poll from | |
128 | * time to time just to make sure. | |
129 | * | |
130 | * For now, the retry frequency is pretty high; normally | |
131 | * a 1 minute timeout would do. See the comment before | |
132 | * nlmclnt_lock for an explanation. | |
133 | */ | |
ecdbf769 | 134 | ret = wait_event_interruptible_timeout(block->b_wait, |
e8c5c045 | 135 | block->b_status != nlm_lck_blocked, |
ecdbf769 | 136 | timeout); |
3a649b88 TM |
137 | if (ret < 0) |
138 | return -ERESTARTSYS; | |
139 | req->a_res.status = block->b_status; | |
140 | return 0; | |
1da177e4 LT |
141 | } |
142 | ||
143 | /* | |
144 | * The server lockd has called us back to tell us the lock was granted | |
145 | */ | |
dcff09f1 | 146 | __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) |
1da177e4 | 147 | { |
5ac5f9d1 TM |
148 | const struct file_lock *fl = &lock->fl; |
149 | const struct nfs_fh *fh = &lock->fh; | |
1da177e4 | 150 | struct nlm_wait *block; |
52921e02 | 151 | __be32 res = nlm_lck_denied; |
1da177e4 LT |
152 | |
153 | /* | |
154 | * Look up blocked request based on arguments. | |
155 | * Warning: must not use cookie to match it! | |
156 | */ | |
4f15e2b1 | 157 | list_for_each_entry(block, &nlm_blocked, b_list) { |
5ac5f9d1 TM |
158 | struct file_lock *fl_blocked = block->b_lock; |
159 | ||
7bab377f TM |
160 | if (fl_blocked->fl_start != fl->fl_start) |
161 | continue; | |
162 | if (fl_blocked->fl_end != fl->fl_end) | |
163 | continue; | |
164 | /* | |
165 | * Careful! The NLM server will return the 32-bit "pid" that | |
166 | * we put on the wire: in this case the lockowner "pid". | |
167 | */ | |
168 | if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid) | |
5ac5f9d1 | 169 | continue; |
4516fc04 | 170 | if (!rpc_cmp_addr(nlm_addr(block->b_host), addr)) |
5ac5f9d1 | 171 | continue; |
225a719f | 172 | if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0) |
5ac5f9d1 TM |
173 | continue; |
174 | /* Alright, we found a lock. Set the return status | |
175 | * and wake up the caller | |
176 | */ | |
e8c5c045 | 177 | block->b_status = nlm_granted; |
5ac5f9d1 TM |
178 | wake_up(&block->b_wait); |
179 | res = nlm_granted; | |
1da177e4 | 180 | } |
ecdbf769 | 181 | return res; |
1da177e4 LT |
182 | } |
183 | ||
184 | /* | |
185 | * The following procedures deal with the recovery of locks after a | |
186 | * server crash. | |
187 | */ | |
188 | ||
1da177e4 LT |
189 | /* |
190 | * Reclaim all locks on server host. We do this by spawning a separate | |
191 | * reclaimer thread. | |
192 | */ | |
193 | void | |
5c8dd29c | 194 | nlmclnt_recovery(struct nlm_host *host) |
1da177e4 | 195 | { |
df94f000 JL |
196 | struct task_struct *task; |
197 | ||
28df955a | 198 | if (!host->h_reclaiming++) { |
1da177e4 | 199 | nlm_get_host(host); |
df94f000 JL |
200 | task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name); |
201 | if (IS_ERR(task)) | |
202 | printk(KERN_ERR "lockd: unable to spawn reclaimer " | |
203 | "thread. Locks for %s won't be reclaimed! " | |
204 | "(%ld)\n", host->h_name, PTR_ERR(task)); | |
1da177e4 LT |
205 | } |
206 | } | |
207 | ||
208 | static int | |
209 | reclaimer(void *ptr) | |
210 | { | |
211 | struct nlm_host *host = (struct nlm_host *) ptr; | |
212 | struct nlm_wait *block; | |
26bcbf96 | 213 | struct file_lock *fl, *next; |
28df955a | 214 | u32 nsmstate; |
1da177e4 | 215 | |
1da177e4 LT |
216 | allow_signal(SIGKILL); |
217 | ||
5c8dd29c OK |
218 | down_write(&host->h_rwsem); |
219 | ||
1da177e4 LT |
220 | /* This one ensures that our parent doesn't terminate while the |
221 | * reclaim is in progress */ | |
222 | lock_kernel(); | |
26a41409 | 223 | lockd_up(); /* note: this cannot fail as lockd is already running */ |
1da177e4 | 224 | |
d019bcf0 | 225 | dprintk("lockd: reclaiming locks for host %s\n", host->h_name); |
5c8dd29c | 226 | |
1da177e4 | 227 | restart: |
28df955a | 228 | nsmstate = host->h_nsmstate; |
5c8dd29c OK |
229 | |
230 | /* Force a portmap getport - the peer's lockd will | |
231 | * most likely end up on a different port. | |
232 | */ | |
0ade060e | 233 | host->h_nextrebind = jiffies; |
5c8dd29c OK |
234 | nlm_rebind_host(host); |
235 | ||
236 | /* First, reclaim all locks that have been granted. */ | |
237 | list_splice_init(&host->h_granted, &host->h_reclaim); | |
26bcbf96 | 238 | list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) { |
4c060b53 | 239 | list_del_init(&fl->fl_u.nfs_fl.list); |
1da177e4 | 240 | |
df94f000 JL |
241 | /* |
242 | * sending this thread a SIGKILL will result in any unreclaimed | |
243 | * locks being removed from the h_granted list. This means that | |
244 | * the kernel will not attempt to reclaim them again if a new | |
245 | * reclaimer thread is spawned for this host. | |
246 | */ | |
1da177e4 | 247 | if (signalled()) |
4c060b53 | 248 | continue; |
28df955a TM |
249 | if (nlmclnt_reclaim(host, fl) != 0) |
250 | continue; | |
251 | list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted); | |
252 | if (host->h_nsmstate != nsmstate) { | |
253 | /* Argh! The server rebooted again! */ | |
28df955a TM |
254 | goto restart; |
255 | } | |
1da177e4 | 256 | } |
5c8dd29c OK |
257 | |
258 | host->h_reclaiming = 0; | |
259 | up_write(&host->h_rwsem); | |
d019bcf0 | 260 | dprintk("NLM: done reclaiming locks for host %s\n", host->h_name); |
1da177e4 LT |
261 | |
262 | /* Now, wake up all processes that sleep on a blocked lock */ | |
4f15e2b1 | 263 | list_for_each_entry(block, &nlm_blocked, b_list) { |
1da177e4 | 264 | if (block->b_host == host) { |
e8c5c045 | 265 | block->b_status = nlm_lck_denied_grace_period; |
1da177e4 LT |
266 | wake_up(&block->b_wait); |
267 | } | |
268 | } | |
269 | ||
270 | /* Release host handle after use */ | |
271 | nlm_release_host(host); | |
272 | lockd_down(); | |
273 | unlock_kernel(); | |
df94f000 | 274 | return 0; |
1da177e4 | 275 | } |