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> | |
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 | */ | |
23 | static 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 | */ | |
33 | struct nlm_wait { | |
4f15e2b1 | 34 | struct list_head b_list; /* linked list */ |
1da177e4 LT |
35 | 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 | ||
4f15e2b1 | 42 | static LIST_HEAD(nlm_blocked); |
1da177e4 LT |
43 | |
44 | /* | |
ecdbf769 | 45 | * Queue up a lock for blocking so that the GRANTED request can see it |
1da177e4 | 46 | */ |
ecdbf769 TM |
47 | int 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 | ||
66 | void nlmclnt_finish_block(struct nlm_rqst *req) | |
1da177e4 | 67 | { |
ecdbf769 TM |
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 | } | |
1da177e4 | 76 | |
ecdbf769 TM |
77 | /* |
78 | * Block on a lock | |
79 | */ | |
80 | long nlmclnt_block(struct nlm_rqst *req, long timeout) | |
81 | { | |
82 | struct nlm_wait *block = req->a_block; | |
83 | long ret; | |
1da177e4 | 84 | |
ecdbf769 TM |
85 | /* 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; | |
1da177e4 LT |
90 | |
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 | */ | |
ecdbf769 TM |
99 | ret = wait_event_interruptible_timeout(block->b_wait, |
100 | block->b_status != NLM_LCK_BLOCKED, | |
101 | timeout); | |
1da177e4 | 102 | |
ecdbf769 TM |
103 | if (block->b_status != NLM_LCK_BLOCKED) { |
104 | req->a_res.status = block->b_status; | |
105 | block->b_status = NLM_LCK_BLOCKED; | |
1da177e4 LT |
106 | } |
107 | ||
ecdbf769 | 108 | return ret; |
1da177e4 LT |
109 | } |
110 | ||
111 | /* | |
112 | * The server lockd has called us back to tell us the lock was granted | |
113 | */ | |
5ac5f9d1 | 114 | u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock) |
1da177e4 | 115 | { |
5ac5f9d1 TM |
116 | const struct file_lock *fl = &lock->fl; |
117 | const struct nfs_fh *fh = &lock->fh; | |
1da177e4 | 118 | struct nlm_wait *block; |
ecdbf769 | 119 | u32 res = nlm_lck_denied; |
1da177e4 LT |
120 | |
121 | /* | |
122 | * Look up blocked request based on arguments. | |
123 | * Warning: must not use cookie to match it! | |
124 | */ | |
4f15e2b1 | 125 | list_for_each_entry(block, &nlm_blocked, b_list) { |
5ac5f9d1 TM |
126 | struct file_lock *fl_blocked = block->b_lock; |
127 | ||
7bab377f TM |
128 | if (fl_blocked->fl_start != fl->fl_start) |
129 | continue; | |
130 | if (fl_blocked->fl_end != fl->fl_end) | |
131 | continue; | |
132 | /* | |
133 | * Careful! The NLM server will return the 32-bit "pid" that | |
134 | * we put on the wire: in this case the lockowner "pid". | |
135 | */ | |
136 | if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid) | |
5ac5f9d1 TM |
137 | continue; |
138 | if (!nlm_cmp_addr(&block->b_host->h_addr, addr)) | |
139 | continue; | |
140 | if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_dentry->d_inode) ,fh) != 0) | |
141 | continue; | |
142 | /* Alright, we found a lock. Set the return status | |
143 | * and wake up the caller | |
144 | */ | |
145 | block->b_status = NLM_LCK_GRANTED; | |
146 | wake_up(&block->b_wait); | |
147 | res = nlm_granted; | |
1da177e4 | 148 | } |
ecdbf769 | 149 | return res; |
1da177e4 LT |
150 | } |
151 | ||
152 | /* | |
153 | * The following procedures deal with the recovery of locks after a | |
154 | * server crash. | |
155 | */ | |
156 | ||
157 | /* | |
158 | * Mark the locks for reclaiming. | |
159 | * FIXME: In 2.5 we don't want to iterate through any global file_lock_list. | |
160 | * Maintain NLM lock reclaiming lists in the nlm_host instead. | |
161 | */ | |
162 | static | |
163 | void nlmclnt_mark_reclaim(struct nlm_host *host) | |
164 | { | |
165 | struct file_lock *fl; | |
166 | struct inode *inode; | |
167 | struct list_head *tmp; | |
168 | ||
169 | list_for_each(tmp, &file_lock_list) { | |
170 | fl = list_entry(tmp, struct file_lock, fl_link); | |
171 | ||
172 | inode = fl->fl_file->f_dentry->d_inode; | |
173 | if (inode->i_sb->s_magic != NFS_SUPER_MAGIC) | |
174 | continue; | |
9b5b1f5b TM |
175 | if (fl->fl_u.nfs_fl.owner == NULL) |
176 | continue; | |
1da177e4 LT |
177 | if (fl->fl_u.nfs_fl.owner->host != host) |
178 | continue; | |
179 | if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_GRANTED)) | |
180 | continue; | |
181 | fl->fl_u.nfs_fl.flags |= NFS_LCK_RECLAIM; | |
182 | } | |
183 | } | |
184 | ||
185 | /* | |
186 | * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number, | |
187 | * that we mark locks for reclaiming, and that we bump the pseudo NSM state. | |
188 | */ | |
189 | static inline | |
190 | void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate) | |
191 | { | |
192 | host->h_monitored = 0; | |
193 | host->h_nsmstate = newstate; | |
194 | host->h_state++; | |
195 | host->h_nextrebind = 0; | |
196 | nlm_rebind_host(host); | |
197 | nlmclnt_mark_reclaim(host); | |
198 | dprintk("NLM: reclaiming locks for host %s", host->h_name); | |
199 | } | |
200 | ||
201 | /* | |
202 | * Reclaim all locks on server host. We do this by spawning a separate | |
203 | * reclaimer thread. | |
204 | */ | |
205 | void | |
206 | nlmclnt_recovery(struct nlm_host *host, u32 newstate) | |
207 | { | |
208 | if (host->h_reclaiming++) { | |
209 | if (host->h_nsmstate == newstate) | |
210 | return; | |
211 | nlmclnt_prepare_reclaim(host, newstate); | |
212 | } else { | |
213 | nlmclnt_prepare_reclaim(host, newstate); | |
214 | nlm_get_host(host); | |
215 | __module_get(THIS_MODULE); | |
216 | if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0) | |
217 | module_put(THIS_MODULE); | |
218 | } | |
219 | } | |
220 | ||
221 | static int | |
222 | reclaimer(void *ptr) | |
223 | { | |
224 | struct nlm_host *host = (struct nlm_host *) ptr; | |
225 | struct nlm_wait *block; | |
226 | struct list_head *tmp; | |
227 | struct file_lock *fl; | |
228 | struct inode *inode; | |
229 | ||
230 | daemonize("%s-reclaim", host->h_name); | |
231 | allow_signal(SIGKILL); | |
232 | ||
233 | /* This one ensures that our parent doesn't terminate while the | |
234 | * reclaim is in progress */ | |
235 | lock_kernel(); | |
236 | lockd_up(); | |
237 | ||
238 | /* First, reclaim all locks that have been marked. */ | |
239 | restart: | |
240 | list_for_each(tmp, &file_lock_list) { | |
241 | fl = list_entry(tmp, struct file_lock, fl_link); | |
242 | ||
243 | inode = fl->fl_file->f_dentry->d_inode; | |
244 | if (inode->i_sb->s_magic != NFS_SUPER_MAGIC) | |
245 | continue; | |
9b5b1f5b TM |
246 | if (fl->fl_u.nfs_fl.owner == NULL) |
247 | continue; | |
1da177e4 LT |
248 | if (fl->fl_u.nfs_fl.owner->host != host) |
249 | continue; | |
250 | if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM)) | |
251 | continue; | |
252 | ||
253 | fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM; | |
254 | nlmclnt_reclaim(host, fl); | |
255 | if (signalled()) | |
256 | break; | |
257 | goto restart; | |
258 | } | |
259 | ||
260 | host->h_reclaiming = 0; | |
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 LT |
264 | if (block->b_host == host) { |
265 | block->b_status = NLM_LCK_DENIED_GRACE_PERIOD; | |
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(); | |
274 | module_put_and_exit(0); | |
275 | } |