Commit | Line | Data |
---|---|---|
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 */ | |
e8c5c045 | 39 | __be32 b_status; /* grant callback status */ |
1da177e4 LT |
40 | }; |
41 | ||
4f15e2b1 | 42 | static LIST_HEAD(nlm_blocked); |
1da177e4 | 43 | |
52c4044d CL |
44 | /** |
45 | * nlmclnt_init - Set up per-NFS mount point lockd data structures | |
883bb163 | 46 | * @nlm_init: pointer to arguments structure |
52c4044d CL |
47 | * |
48 | * Returns pointer to an appropriate nlm_host struct, | |
49 | * or an ERR_PTR value. | |
50 | */ | |
883bb163 | 51 | struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init) |
52c4044d CL |
52 | { |
53 | struct nlm_host *host; | |
883bb163 | 54 | u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4; |
52c4044d CL |
55 | int status; |
56 | ||
26a41409 | 57 | status = lockd_up(); |
52c4044d CL |
58 | if (status < 0) |
59 | return ERR_PTR(status); | |
60 | ||
d7d20440 | 61 | host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen, |
883bb163 | 62 | nlm_init->protocol, nlm_version, |
d7d20440 | 63 | nlm_init->hostname); |
52c4044d CL |
64 | if (host == NULL) { |
65 | lockd_down(); | |
66 | return ERR_PTR(-ENOLCK); | |
67 | } | |
68 | ||
69 | return host; | |
70 | } | |
71 | EXPORT_SYMBOL_GPL(nlmclnt_init); | |
72 | ||
73 | /** | |
74 | * nlmclnt_done - Release resources allocated by nlmclnt_init() | |
75 | * @host: nlm_host structure reserved by nlmclnt_init() | |
76 | * | |
77 | */ | |
78 | void nlmclnt_done(struct nlm_host *host) | |
79 | { | |
80 | nlm_release_host(host); | |
81 | lockd_down(); | |
82 | } | |
83 | EXPORT_SYMBOL_GPL(nlmclnt_done); | |
84 | ||
1da177e4 | 85 | /* |
ecdbf769 | 86 | * Queue up a lock for blocking so that the GRANTED request can see it |
1da177e4 | 87 | */ |
3a649b88 | 88 | struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl) |
ecdbf769 TM |
89 | { |
90 | struct nlm_wait *block; | |
91 | ||
ecdbf769 | 92 | block = kmalloc(sizeof(*block), GFP_KERNEL); |
3a649b88 TM |
93 | if (block != NULL) { |
94 | block->b_host = host; | |
95 | block->b_lock = fl; | |
96 | init_waitqueue_head(&block->b_wait); | |
e8c5c045 | 97 | block->b_status = nlm_lck_blocked; |
3a649b88 TM |
98 | list_add(&block->b_list, &nlm_blocked); |
99 | } | |
100 | return block; | |
ecdbf769 TM |
101 | } |
102 | ||
3a649b88 | 103 | void nlmclnt_finish_block(struct nlm_wait *block) |
1da177e4 | 104 | { |
ecdbf769 TM |
105 | if (block == NULL) |
106 | return; | |
ecdbf769 TM |
107 | list_del(&block->b_list); |
108 | kfree(block); | |
109 | } | |
1da177e4 | 110 | |
ecdbf769 TM |
111 | /* |
112 | * Block on a lock | |
113 | */ | |
3a649b88 | 114 | int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout) |
ecdbf769 | 115 | { |
ecdbf769 | 116 | long ret; |
1da177e4 | 117 | |
ecdbf769 TM |
118 | /* A borken server might ask us to block even if we didn't |
119 | * request it. Just say no! | |
120 | */ | |
3a649b88 | 121 | if (block == NULL) |
ecdbf769 | 122 | return -EAGAIN; |
1da177e4 LT |
123 | |
124 | /* Go to sleep waiting for GRANT callback. Some servers seem | |
125 | * to lose callbacks, however, so we're going to poll from | |
126 | * time to time just to make sure. | |
127 | * | |
128 | * For now, the retry frequency is pretty high; normally | |
129 | * a 1 minute timeout would do. See the comment before | |
130 | * nlmclnt_lock for an explanation. | |
131 | */ | |
ecdbf769 | 132 | ret = wait_event_interruptible_timeout(block->b_wait, |
e8c5c045 | 133 | block->b_status != nlm_lck_blocked, |
ecdbf769 | 134 | timeout); |
3a649b88 TM |
135 | if (ret < 0) |
136 | return -ERESTARTSYS; | |
137 | req->a_res.status = block->b_status; | |
138 | return 0; | |
1da177e4 LT |
139 | } |
140 | ||
141 | /* | |
142 | * The server lockd has called us back to tell us the lock was granted | |
143 | */ | |
dcff09f1 | 144 | __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) |
1da177e4 | 145 | { |
5ac5f9d1 TM |
146 | const struct file_lock *fl = &lock->fl; |
147 | const struct nfs_fh *fh = &lock->fh; | |
1da177e4 | 148 | struct nlm_wait *block; |
52921e02 | 149 | __be32 res = nlm_lck_denied; |
1da177e4 LT |
150 | |
151 | /* | |
152 | * Look up blocked request based on arguments. | |
153 | * Warning: must not use cookie to match it! | |
154 | */ | |
4f15e2b1 | 155 | list_for_each_entry(block, &nlm_blocked, b_list) { |
5ac5f9d1 TM |
156 | struct file_lock *fl_blocked = block->b_lock; |
157 | ||
7bab377f TM |
158 | if (fl_blocked->fl_start != fl->fl_start) |
159 | continue; | |
160 | if (fl_blocked->fl_end != fl->fl_end) | |
161 | continue; | |
162 | /* | |
163 | * Careful! The NLM server will return the 32-bit "pid" that | |
164 | * we put on the wire: in this case the lockowner "pid". | |
165 | */ | |
166 | if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid) | |
5ac5f9d1 | 167 | continue; |
dcff09f1 | 168 | if (!nlm_cmp_addr(nlm_addr(block->b_host), addr)) |
5ac5f9d1 | 169 | continue; |
225a719f | 170 | if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0) |
5ac5f9d1 TM |
171 | continue; |
172 | /* Alright, we found a lock. Set the return status | |
173 | * and wake up the caller | |
174 | */ | |
e8c5c045 | 175 | block->b_status = nlm_granted; |
5ac5f9d1 TM |
176 | wake_up(&block->b_wait); |
177 | res = nlm_granted; | |
1da177e4 | 178 | } |
ecdbf769 | 179 | return res; |
1da177e4 LT |
180 | } |
181 | ||
182 | /* | |
183 | * The following procedures deal with the recovery of locks after a | |
184 | * server crash. | |
185 | */ | |
186 | ||
1da177e4 LT |
187 | /* |
188 | * Reclaim all locks on server host. We do this by spawning a separate | |
189 | * reclaimer thread. | |
190 | */ | |
191 | void | |
5c8dd29c | 192 | nlmclnt_recovery(struct nlm_host *host) |
1da177e4 | 193 | { |
28df955a | 194 | if (!host->h_reclaiming++) { |
1da177e4 LT |
195 | nlm_get_host(host); |
196 | __module_get(THIS_MODULE); | |
550facd1 | 197 | if (kernel_thread(reclaimer, host, CLONE_FS | CLONE_FILES) < 0) |
1da177e4 LT |
198 | module_put(THIS_MODULE); |
199 | } | |
200 | } | |
201 | ||
202 | static int | |
203 | reclaimer(void *ptr) | |
204 | { | |
205 | struct nlm_host *host = (struct nlm_host *) ptr; | |
206 | struct nlm_wait *block; | |
26bcbf96 | 207 | struct file_lock *fl, *next; |
28df955a | 208 | u32 nsmstate; |
1da177e4 LT |
209 | |
210 | daemonize("%s-reclaim", host->h_name); | |
211 | allow_signal(SIGKILL); | |
212 | ||
5c8dd29c OK |
213 | down_write(&host->h_rwsem); |
214 | ||
1da177e4 LT |
215 | /* This one ensures that our parent doesn't terminate while the |
216 | * reclaim is in progress */ | |
217 | lock_kernel(); | |
26a41409 | 218 | lockd_up(); /* note: this cannot fail as lockd is already running */ |
1da177e4 | 219 | |
d019bcf0 | 220 | dprintk("lockd: reclaiming locks for host %s\n", host->h_name); |
5c8dd29c | 221 | |
1da177e4 | 222 | restart: |
28df955a | 223 | nsmstate = host->h_nsmstate; |
5c8dd29c OK |
224 | |
225 | /* Force a portmap getport - the peer's lockd will | |
226 | * most likely end up on a different port. | |
227 | */ | |
0ade060e | 228 | host->h_nextrebind = jiffies; |
5c8dd29c OK |
229 | nlm_rebind_host(host); |
230 | ||
231 | /* First, reclaim all locks that have been granted. */ | |
232 | list_splice_init(&host->h_granted, &host->h_reclaim); | |
26bcbf96 | 233 | list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) { |
4c060b53 | 234 | list_del_init(&fl->fl_u.nfs_fl.list); |
1da177e4 | 235 | |
5c8dd29c | 236 | /* Why are we leaking memory here? --okir */ |
1da177e4 | 237 | if (signalled()) |
4c060b53 | 238 | continue; |
28df955a TM |
239 | if (nlmclnt_reclaim(host, fl) != 0) |
240 | continue; | |
241 | list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted); | |
242 | if (host->h_nsmstate != nsmstate) { | |
243 | /* Argh! The server rebooted again! */ | |
28df955a TM |
244 | goto restart; |
245 | } | |
1da177e4 | 246 | } |
5c8dd29c OK |
247 | |
248 | host->h_reclaiming = 0; | |
249 | up_write(&host->h_rwsem); | |
d019bcf0 | 250 | dprintk("NLM: done reclaiming locks for host %s\n", host->h_name); |
1da177e4 LT |
251 | |
252 | /* Now, wake up all processes that sleep on a blocked lock */ | |
4f15e2b1 | 253 | list_for_each_entry(block, &nlm_blocked, b_list) { |
1da177e4 | 254 | if (block->b_host == host) { |
e8c5c045 | 255 | block->b_status = nlm_lck_denied_grace_period; |
1da177e4 LT |
256 | wake_up(&block->b_wait); |
257 | } | |
258 | } | |
259 | ||
260 | /* Release host handle after use */ | |
261 | nlm_release_host(host); | |
262 | lockd_down(); | |
263 | unlock_kernel(); | |
264 | module_put_and_exit(0); | |
265 | } |