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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090011#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#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>
Jeff Laytondf94f002008-12-23 15:21:33 -050017#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
19#define NLMDBG_FACILITY NLMDBG_CLIENT
20
21/*
22 * Local function prototypes
23 */
24static 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 */
34struct nlm_wait {
Trond Myklebust4f15e2b2005-06-22 17:16:31 +000035 struct list_head b_list; /* linked list */
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 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 */
Al Viroe8c5c042006-12-13 00:35:03 -080040 __be32 b_status; /* grant callback status */
Linus Torvalds1da177e2005-04-16 15:20:36 -070041};
42
Trond Myklebust4f15e2b2005-06-22 17:16:31 +000043static LIST_HEAD(nlm_blocked);
Bryan Schumaker63185942010-09-22 09:50:35 -040044static DEFINE_SPINLOCK(nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
Chuck Lever52c40442008-01-11 17:09:44 -050046/**
47 * nlmclnt_init - Set up per-NFS mount point lockd data structures
Chuck Lever883bb162008-01-15 16:04:20 -050048 * @nlm_init: pointer to arguments structure
Chuck Lever52c40442008-01-11 17:09:44 -050049 *
50 * Returns pointer to an appropriate nlm_host struct,
51 * or an ERR_PTR value.
52 */
Chuck Lever883bb162008-01-15 16:04:20 -050053struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
Chuck Lever52c40442008-01-11 17:09:44 -050054{
55 struct nlm_host *host;
Chuck Lever883bb162008-01-15 16:04:20 -050056 u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
Chuck Lever52c40442008-01-11 17:09:44 -050057 int status;
58
Chuck Lever26a41402008-10-03 17:15:30 -040059 status = lockd_up();
Chuck Lever52c40442008-01-11 17:09:44 -050060 if (status < 0)
61 return ERR_PTR(status);
62
Chuck Leverd7d20442008-10-03 12:50:21 -040063 host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
Chuck Lever883bb162008-01-15 16:04:20 -050064 nlm_init->protocol, nlm_version,
Stanislav Kinsbursky66697bf2012-01-31 15:08:13 +040065 nlm_init->hostname, nlm_init->noresvport,
66 nlm_init->net);
Chuck Lever52c40442008-01-11 17:09:44 -050067 if (host == NULL) {
68 lockd_down();
69 return ERR_PTR(-ENOLCK);
70 }
71
72 return host;
73}
74EXPORT_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 */
81void nlmclnt_done(struct nlm_host *host)
82{
Chuck Lever8ea6ecc2010-12-14 15:05:52 +000083 nlmclnt_release_host(host);
Chuck Lever52c40442008-01-11 17:09:44 -050084 lockd_down();
85}
86EXPORT_SYMBOL_GPL(nlmclnt_done);
87
Linus Torvalds1da177e2005-04-16 15:20:36 -070088/*
Trond Myklebustecdbf762005-06-22 17:16:31 +000089 * Queue up a lock for blocking so that the GRANTED request can see it
90 */
Trond Myklebust3a649b82006-03-20 13:44:44 -050091struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
Trond Myklebustecdbf762005-06-22 17:16:31 +000092{
93 struct nlm_wait *block;
94
Trond Myklebustecdbf762005-06-22 17:16:31 +000095 block = kmalloc(sizeof(*block), GFP_KERNEL);
Trond Myklebust3a649b82006-03-20 13:44:44 -050096 if (block != NULL) {
97 block->b_host = host;
98 block->b_lock = fl;
99 init_waitqueue_head(&block->b_wait);
Al Viroe8c5c042006-12-13 00:35:03 -0800100 block->b_status = nlm_lck_blocked;
Bryan Schumaker63185942010-09-22 09:50:35 -0400101
102 spin_lock(&nlm_blocked_lock);
Trond Myklebust3a649b82006-03-20 13:44:44 -0500103 list_add(&block->b_list, &nlm_blocked);
Bryan Schumaker63185942010-09-22 09:50:35 -0400104 spin_unlock(&nlm_blocked_lock);
Trond Myklebust3a649b82006-03-20 13:44:44 -0500105 }
106 return block;
Trond Myklebustecdbf762005-06-22 17:16:31 +0000107}
108
Trond Myklebust3a649b82006-03-20 13:44:44 -0500109void nlmclnt_finish_block(struct nlm_wait *block)
Trond Myklebustecdbf762005-06-22 17:16:31 +0000110{
Trond Myklebustecdbf762005-06-22 17:16:31 +0000111 if (block == NULL)
112 return;
Bryan Schumaker63185942010-09-22 09:50:35 -0400113 spin_lock(&nlm_blocked_lock);
Trond Myklebustecdbf762005-06-22 17:16:31 +0000114 list_del(&block->b_list);
Bryan Schumaker63185942010-09-22 09:50:35 -0400115 spin_unlock(&nlm_blocked_lock);
Trond Myklebustecdbf762005-06-22 17:16:31 +0000116 kfree(block);
117}
118
119/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 * Block on a lock
121 */
Trond Myklebust3a649b82006-03-20 13:44:44 -0500122int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123{
Trond Myklebustecdbf762005-06-22 17:16:31 +0000124 long ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
Trond Myklebustecdbf762005-06-22 17:16:31 +0000126 /* A borken server might ask us to block even if we didn't
127 * request it. Just say no!
128 */
Trond Myklebust3a649b82006-03-20 13:44:44 -0500129 if (block == NULL)
Trond Myklebustecdbf762005-06-22 17:16:31 +0000130 return -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
132 /* Go to sleep waiting for GRANT callback. Some servers seem
133 * to lose callbacks, however, so we're going to poll from
134 * time to time just to make sure.
135 *
136 * For now, the retry frequency is pretty high; normally
137 * a 1 minute timeout would do. See the comment before
138 * nlmclnt_lock for an explanation.
139 */
Trond Myklebustecdbf762005-06-22 17:16:31 +0000140 ret = wait_event_interruptible_timeout(block->b_wait,
Al Viroe8c5c042006-12-13 00:35:03 -0800141 block->b_status != nlm_lck_blocked,
Trond Myklebustecdbf762005-06-22 17:16:31 +0000142 timeout);
Trond Myklebust3a649b82006-03-20 13:44:44 -0500143 if (ret < 0)
144 return -ERESTARTSYS;
145 req->a_res.status = block->b_status;
146 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
149/*
150 * The server lockd has called us back to tell us the lock was granted
151 */
Chuck Leverdcff09f2008-10-03 12:50:36 -0400152__be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153{
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800154 const struct file_lock *fl = &lock->fl;
155 const struct nfs_fh *fh = &lock->fh;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 struct nlm_wait *block;
Al Viro52921e02006-10-19 23:28:46 -0700157 __be32 res = nlm_lck_denied;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
159 /*
160 * Look up blocked request based on arguments.
161 * Warning: must not use cookie to match it!
162 */
Bryan Schumaker63185942010-09-22 09:50:35 -0400163 spin_lock(&nlm_blocked_lock);
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000164 list_for_each_entry(block, &nlm_blocked, b_list) {
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800165 struct file_lock *fl_blocked = block->b_lock;
166
Trond Myklebust7bab3772006-03-20 13:44:06 -0500167 if (fl_blocked->fl_start != fl->fl_start)
168 continue;
169 if (fl_blocked->fl_end != fl->fl_end)
170 continue;
171 /*
172 * Careful! The NLM server will return the 32-bit "pid" that
173 * we put on the wire: in this case the lockowner "pid".
174 */
175 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800176 continue;
Jeff Layton4516fc02009-08-14 12:57:54 -0400177 if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800178 continue;
Josef Sipek225a7192006-12-08 02:37:18 -0800179 if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0)
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800180 continue;
181 /* Alright, we found a lock. Set the return status
182 * and wake up the caller
183 */
Al Viroe8c5c042006-12-13 00:35:03 -0800184 block->b_status = nlm_granted;
Trond Myklebust5ac5f9d2006-02-14 13:53:04 -0800185 wake_up(&block->b_wait);
186 res = nlm_granted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 }
Bryan Schumaker63185942010-09-22 09:50:35 -0400188 spin_unlock(&nlm_blocked_lock);
Trond Myklebustecdbf762005-06-22 17:16:31 +0000189 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190}
191
192/*
193 * The following procedures deal with the recovery of locks after a
194 * server crash.
195 */
196
197/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 * Reclaim all locks on server host. We do this by spawning a separate
199 * reclaimer thread.
200 */
201void
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700202nlmclnt_recovery(struct nlm_host *host)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203{
Jeff Laytondf94f002008-12-23 15:21:33 -0500204 struct task_struct *task;
205
Trond Myklebust28df9552006-06-09 09:40:27 -0400206 if (!host->h_reclaiming++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 nlm_get_host(host);
Jeff Laytondf94f002008-12-23 15:21:33 -0500208 task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
209 if (IS_ERR(task))
210 printk(KERN_ERR "lockd: unable to spawn reclaimer "
211 "thread. Locks for %s won't be reclaimed! "
212 "(%ld)\n", host->h_name, PTR_ERR(task));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 }
214}
215
216static int
217reclaimer(void *ptr)
218{
219 struct nlm_host *host = (struct nlm_host *) ptr;
220 struct nlm_wait *block;
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500221 struct file_lock *fl, *next;
Trond Myklebust28df9552006-06-09 09:40:27 -0400222 u32 nsmstate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 allow_signal(SIGKILL);
225
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700226 down_write(&host->h_rwsem);
Chuck Lever26a41402008-10-03 17:15:30 -0400227 lockd_up(); /* note: this cannot fail as lockd is already running */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Adrian Bunkd019bcf2007-01-29 13:19:51 -0800229 dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231restart:
Trond Myklebust28df9552006-06-09 09:40:27 -0400232 nsmstate = host->h_nsmstate;
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700233
234 /* Force a portmap getport - the peer's lockd will
235 * most likely end up on a different port.
236 */
Olaf Kirch0ade0602006-10-04 02:16:04 -0700237 host->h_nextrebind = jiffies;
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700238 nlm_rebind_host(host);
239
240 /* First, reclaim all locks that have been granted. */
241 list_splice_init(&host->h_granted, &host->h_reclaim);
Christoph Hellwig26bcbf92006-03-20 13:44:40 -0500242 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
Trond Myklebust4c060b52006-03-20 13:44:41 -0500243 list_del_init(&fl->fl_u.nfs_fl.list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
Jeff Laytondf94f002008-12-23 15:21:33 -0500245 /*
246 * sending this thread a SIGKILL will result in any unreclaimed
247 * locks being removed from the h_granted list. This means that
248 * the kernel will not attempt to reclaim them again if a new
249 * reclaimer thread is spawned for this host.
250 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 if (signalled())
Trond Myklebust4c060b52006-03-20 13:44:41 -0500252 continue;
Trond Myklebust28df9552006-06-09 09:40:27 -0400253 if (nlmclnt_reclaim(host, fl) != 0)
254 continue;
255 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
256 if (host->h_nsmstate != nsmstate) {
257 /* Argh! The server rebooted again! */
Trond Myklebust28df9552006-06-09 09:40:27 -0400258 goto restart;
259 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 }
Olaf Kirch5c8dd292006-10-04 02:15:55 -0700261
262 host->h_reclaiming = 0;
263 up_write(&host->h_rwsem);
Adrian Bunkd019bcf2007-01-29 13:19:51 -0800264 dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265
266 /* Now, wake up all processes that sleep on a blocked lock */
Bryan Schumaker63185942010-09-22 09:50:35 -0400267 spin_lock(&nlm_blocked_lock);
Trond Myklebust4f15e2b2005-06-22 17:16:31 +0000268 list_for_each_entry(block, &nlm_blocked, b_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 if (block->b_host == host) {
Al Viroe8c5c042006-12-13 00:35:03 -0800270 block->b_status = nlm_lck_denied_grace_period;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 wake_up(&block->b_wait);
272 }
273 }
Bryan Schumaker63185942010-09-22 09:50:35 -0400274 spin_unlock(&nlm_blocked_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
276 /* Release host handle after use */
Chuck Lever8ea6ecc2010-12-14 15:05:52 +0000277 nlmclnt_release_host(host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 lockd_down();
Jeff Laytondf94f002008-12-23 15:21:33 -0500279 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280}