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> | |
5a0e3ad6 | 11 | #include <linux/slab.h> |
1da177e4 LT |
12 | #include <linux/time.h> |
13 | #include <linux/nfs_fs.h> | |
5976687a | 14 | #include <linux/sunrpc/addr.h> |
1da177e4 LT |
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 | ||
e3f70ead | 59 | status = lockd_up(nlm_init->net); |
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, |
66697bfd SK |
65 | nlm_init->hostname, nlm_init->noresvport, |
66 | nlm_init->net); | |
52c4044d | 67 | if (host == NULL) { |
e3f70ead | 68 | lockd_down(nlm_init->net); |
52c4044d CL |
69 | return ERR_PTR(-ENOLCK); |
70 | } | |
71 | ||
72 | return host; | |
73 | } | |
74 | EXPORT_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 | */ | |
81 | void nlmclnt_done(struct nlm_host *host) | |
82 | { | |
e3f70ead SK |
83 | struct net *net = host->net; |
84 | ||
8ea6ecc8 | 85 | nlmclnt_release_host(host); |
e3f70ead | 86 | lockd_down(net); |
52c4044d CL |
87 | } |
88 | EXPORT_SYMBOL_GPL(nlmclnt_done); | |
89 | ||
1da177e4 | 90 | /* |
ecdbf769 | 91 | * Queue up a lock for blocking so that the GRANTED request can see it |
1da177e4 | 92 | */ |
3a649b88 | 93 | struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl) |
ecdbf769 TM |
94 | { |
95 | struct nlm_wait *block; | |
96 | ||
ecdbf769 | 97 | block = kmalloc(sizeof(*block), GFP_KERNEL); |
3a649b88 TM |
98 | if (block != NULL) { |
99 | block->b_host = host; | |
100 | block->b_lock = fl; | |
101 | init_waitqueue_head(&block->b_wait); | |
e8c5c045 | 102 | block->b_status = nlm_lck_blocked; |
63185942 BS |
103 | |
104 | spin_lock(&nlm_blocked_lock); | |
3a649b88 | 105 | list_add(&block->b_list, &nlm_blocked); |
63185942 | 106 | spin_unlock(&nlm_blocked_lock); |
3a649b88 TM |
107 | } |
108 | return block; | |
ecdbf769 TM |
109 | } |
110 | ||
3a649b88 | 111 | void nlmclnt_finish_block(struct nlm_wait *block) |
1da177e4 | 112 | { |
ecdbf769 TM |
113 | if (block == NULL) |
114 | return; | |
63185942 | 115 | spin_lock(&nlm_blocked_lock); |
ecdbf769 | 116 | list_del(&block->b_list); |
63185942 | 117 | spin_unlock(&nlm_blocked_lock); |
ecdbf769 TM |
118 | kfree(block); |
119 | } | |
1da177e4 | 120 | |
ecdbf769 TM |
121 | /* |
122 | * Block on a lock | |
123 | */ | |
3a649b88 | 124 | int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout) |
ecdbf769 | 125 | { |
ecdbf769 | 126 | long ret; |
1da177e4 | 127 | |
ecdbf769 TM |
128 | /* A borken server might ask us to block even if we didn't |
129 | * request it. Just say no! | |
130 | */ | |
3a649b88 | 131 | if (block == NULL) |
ecdbf769 | 132 | return -EAGAIN; |
1da177e4 LT |
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 | */ | |
ecdbf769 | 142 | ret = wait_event_interruptible_timeout(block->b_wait, |
e8c5c045 | 143 | block->b_status != nlm_lck_blocked, |
ecdbf769 | 144 | timeout); |
3a649b88 TM |
145 | if (ret < 0) |
146 | return -ERESTARTSYS; | |
1dfd89af TM |
147 | /* Reset the lock status after a server reboot so we resend */ |
148 | if (block->b_status == nlm_lck_denied_grace_period) | |
149 | block->b_status = nlm_lck_blocked; | |
3a649b88 TM |
150 | req->a_res.status = block->b_status; |
151 | return 0; | |
1da177e4 LT |
152 | } |
153 | ||
154 | /* | |
155 | * The server lockd has called us back to tell us the lock was granted | |
156 | */ | |
dcff09f1 | 157 | __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) |
1da177e4 | 158 | { |
5ac5f9d1 TM |
159 | const struct file_lock *fl = &lock->fl; |
160 | const struct nfs_fh *fh = &lock->fh; | |
1da177e4 | 161 | struct nlm_wait *block; |
52921e02 | 162 | __be32 res = nlm_lck_denied; |
1da177e4 LT |
163 | |
164 | /* | |
165 | * Look up blocked request based on arguments. | |
166 | * Warning: must not use cookie to match it! | |
167 | */ | |
63185942 | 168 | spin_lock(&nlm_blocked_lock); |
4f15e2b1 | 169 | list_for_each_entry(block, &nlm_blocked, b_list) { |
5ac5f9d1 TM |
170 | struct file_lock *fl_blocked = block->b_lock; |
171 | ||
7bab377f TM |
172 | if (fl_blocked->fl_start != fl->fl_start) |
173 | continue; | |
174 | if (fl_blocked->fl_end != fl->fl_end) | |
175 | continue; | |
176 | /* | |
177 | * Careful! The NLM server will return the 32-bit "pid" that | |
178 | * we put on the wire: in this case the lockowner "pid". | |
179 | */ | |
180 | if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid) | |
5ac5f9d1 | 181 | continue; |
4516fc04 | 182 | if (!rpc_cmp_addr(nlm_addr(block->b_host), addr)) |
5ac5f9d1 | 183 | continue; |
496ad9aa | 184 | if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0) |
5ac5f9d1 TM |
185 | continue; |
186 | /* Alright, we found a lock. Set the return status | |
187 | * and wake up the caller | |
188 | */ | |
e8c5c045 | 189 | block->b_status = nlm_granted; |
5ac5f9d1 TM |
190 | wake_up(&block->b_wait); |
191 | res = nlm_granted; | |
1da177e4 | 192 | } |
63185942 | 193 | spin_unlock(&nlm_blocked_lock); |
ecdbf769 | 194 | return res; |
1da177e4 LT |
195 | } |
196 | ||
197 | /* | |
198 | * The following procedures deal with the recovery of locks after a | |
199 | * server crash. | |
200 | */ | |
201 | ||
1da177e4 LT |
202 | /* |
203 | * Reclaim all locks on server host. We do this by spawning a separate | |
204 | * reclaimer thread. | |
205 | */ | |
206 | void | |
5c8dd29c | 207 | nlmclnt_recovery(struct nlm_host *host) |
1da177e4 | 208 | { |
df94f000 JL |
209 | struct task_struct *task; |
210 | ||
28df955a | 211 | if (!host->h_reclaiming++) { |
1da177e4 | 212 | nlm_get_host(host); |
df94f000 JL |
213 | task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name); |
214 | if (IS_ERR(task)) | |
215 | printk(KERN_ERR "lockd: unable to spawn reclaimer " | |
216 | "thread. Locks for %s won't be reclaimed! " | |
217 | "(%ld)\n", host->h_name, PTR_ERR(task)); | |
1da177e4 LT |
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; | |
f25cc71e | 226 | struct nlm_rqst *req; |
26bcbf96 | 227 | struct file_lock *fl, *next; |
28df955a | 228 | u32 nsmstate; |
e3f70ead | 229 | struct net *net = host->net; |
1da177e4 | 230 | |
f25cc71e TG |
231 | req = kmalloc(sizeof(*req), GFP_KERNEL); |
232 | if (!req) { | |
233 | printk(KERN_ERR "lockd: reclaimer unable to alloc memory." | |
234 | " Locks for %s won't be reclaimed!\n", | |
235 | host->h_name); | |
236 | return 0; | |
237 | } | |
238 | ||
1da177e4 LT |
239 | allow_signal(SIGKILL); |
240 | ||
5c8dd29c | 241 | down_write(&host->h_rwsem); |
e3f70ead | 242 | lockd_up(net); /* note: this cannot fail as lockd is already running */ |
1da177e4 | 243 | |
d019bcf0 | 244 | dprintk("lockd: reclaiming locks for host %s\n", host->h_name); |
5c8dd29c | 245 | |
1da177e4 | 246 | restart: |
28df955a | 247 | nsmstate = host->h_nsmstate; |
5c8dd29c OK |
248 | |
249 | /* Force a portmap getport - the peer's lockd will | |
250 | * most likely end up on a different port. | |
251 | */ | |
0ade060e | 252 | host->h_nextrebind = jiffies; |
5c8dd29c OK |
253 | nlm_rebind_host(host); |
254 | ||
255 | /* First, reclaim all locks that have been granted. */ | |
256 | list_splice_init(&host->h_granted, &host->h_reclaim); | |
26bcbf96 | 257 | list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) { |
4c060b53 | 258 | list_del_init(&fl->fl_u.nfs_fl.list); |
1da177e4 | 259 | |
df94f000 JL |
260 | /* |
261 | * sending this thread a SIGKILL will result in any unreclaimed | |
262 | * locks being removed from the h_granted list. This means that | |
263 | * the kernel will not attempt to reclaim them again if a new | |
264 | * reclaimer thread is spawned for this host. | |
265 | */ | |
1da177e4 | 266 | if (signalled()) |
4c060b53 | 267 | continue; |
f25cc71e | 268 | if (nlmclnt_reclaim(host, fl, req) != 0) |
28df955a TM |
269 | continue; |
270 | list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted); | |
271 | if (host->h_nsmstate != nsmstate) { | |
272 | /* Argh! The server rebooted again! */ | |
28df955a TM |
273 | goto restart; |
274 | } | |
1da177e4 | 275 | } |
5c8dd29c OK |
276 | |
277 | host->h_reclaiming = 0; | |
278 | up_write(&host->h_rwsem); | |
d019bcf0 | 279 | dprintk("NLM: done reclaiming locks for host %s\n", host->h_name); |
1da177e4 LT |
280 | |
281 | /* Now, wake up all processes that sleep on a blocked lock */ | |
63185942 | 282 | spin_lock(&nlm_blocked_lock); |
4f15e2b1 | 283 | list_for_each_entry(block, &nlm_blocked, b_list) { |
1da177e4 | 284 | if (block->b_host == host) { |
e8c5c045 | 285 | block->b_status = nlm_lck_denied_grace_period; |
1da177e4 LT |
286 | wake_up(&block->b_wait); |
287 | } | |
288 | } | |
63185942 | 289 | spin_unlock(&nlm_blocked_lock); |
1da177e4 LT |
290 | |
291 | /* Release host handle after use */ | |
8ea6ecc8 | 292 | nlmclnt_release_host(host); |
e3f70ead | 293 | lockd_down(net); |
f25cc71e | 294 | kfree(req); |
df94f000 | 295 | return 0; |
1da177e4 | 296 | } |