1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/fs/lockd/clntlock.c
5 * Lock handling for the client side NLM implementation
7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <linux/slab.h>
13 #include <linux/time.h>
14 #include <linux/nfs_fs.h>
15 #include <linux/sunrpc/addr.h>
16 #include <linux/sunrpc/svc.h>
17 #include <linux/sunrpc/svc_xprt.h>
18 #include <linux/lockd/lockd.h>
19 #include <linux/kthread.h>
23 #define NLMDBG_FACILITY NLMDBG_CLIENT
26 * Local function prototypes
28 static int reclaimer(void *ptr);
31 * The following functions handle blocking and granting from the
35 static LIST_HEAD(nlm_blocked);
36 static DEFINE_SPINLOCK(nlm_blocked_lock);
39 * nlmclnt_init - Set up per-NFS mount point lockd data structures
40 * @nlm_init: pointer to arguments structure
42 * Returns pointer to an appropriate nlm_host struct,
43 * or an ERR_PTR value.
45 struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
47 struct nlm_host *host;
48 u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
51 status = lockd_up(nlm_init->net, nlm_init->cred);
53 return ERR_PTR(status);
55 host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
56 nlm_init->protocol, nlm_version,
57 nlm_init->hostname, nlm_init->noresvport,
58 nlm_init->net, nlm_init->cred);
61 if (host->h_rpcclnt == NULL && nlm_bind_host(host) == NULL)
64 host->h_nlmclnt_ops = nlm_init->nlmclnt_ops;
67 nlmclnt_release_host(host);
69 lockd_down(nlm_init->net);
70 return ERR_PTR(-ENOLCK);
72 EXPORT_SYMBOL_GPL(nlmclnt_init);
75 * nlmclnt_done - Release resources allocated by nlmclnt_init()
76 * @host: nlm_host structure reserved by nlmclnt_init()
79 void nlmclnt_done(struct nlm_host *host)
81 struct net *net = host->net;
83 nlmclnt_release_host(host);
86 EXPORT_SYMBOL_GPL(nlmclnt_done);
88 void nlmclnt_prepare_block(struct nlm_wait *block, struct nlm_host *host, struct file_lock *fl)
92 init_waitqueue_head(&block->b_wait);
93 block->b_status = nlm_lck_blocked;
97 * Queue up a lock for blocking so that the GRANTED request can see it
99 void nlmclnt_queue_block(struct nlm_wait *block)
101 spin_lock(&nlm_blocked_lock);
102 list_add(&block->b_list, &nlm_blocked);
103 spin_unlock(&nlm_blocked_lock);
107 * Dequeue the block and return its final status
109 __be32 nlmclnt_dequeue_block(struct nlm_wait *block)
113 spin_lock(&nlm_blocked_lock);
114 list_del(&block->b_list);
115 status = block->b_status;
116 spin_unlock(&nlm_blocked_lock);
123 int nlmclnt_wait(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
127 /* A borken server might ask us to block even if we didn't
128 * request it. Just say no!
133 /* Go to sleep waiting for GRANT callback. Some servers seem
134 * to lose callbacks, however, so we're going to poll from
135 * time to time just to make sure.
137 * For now, the retry frequency is pretty high; normally
138 * a 1 minute timeout would do. See the comment before
139 * nlmclnt_lock for an explanation.
141 ret = wait_event_interruptible_timeout(block->b_wait,
142 block->b_status != nlm_lck_blocked,
146 /* Reset the lock status after a server reboot so we resend */
147 if (block->b_status == nlm_lck_denied_grace_period)
148 block->b_status = nlm_lck_blocked;
153 * The server lockd has called us back to tell us the lock was granted
155 __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
157 const struct file_lock *fl = &lock->fl;
158 const struct nfs_fh *fh = &lock->fh;
159 struct nlm_wait *block;
160 __be32 res = nlm_lck_denied;
163 * Look up blocked request based on arguments.
164 * Warning: must not use cookie to match it!
166 spin_lock(&nlm_blocked_lock);
167 list_for_each_entry(block, &nlm_blocked, b_list) {
168 struct file_lock *fl_blocked = block->b_lock;
170 if (fl_blocked->fl_start != fl->fl_start)
172 if (fl_blocked->fl_end != fl->fl_end)
175 * Careful! The NLM server will return the 32-bit "pid" that
176 * we put on the wire: in this case the lockowner "pid".
178 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
180 if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
182 if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)), fh) != 0)
184 /* Alright, we found a lock. Set the return status
185 * and wake up the caller
187 block->b_status = nlm_granted;
188 wake_up(&block->b_wait);
191 spin_unlock(&nlm_blocked_lock);
192 trace_nlmclnt_grant(lock, addr, svc_addr_len(addr), res);
197 * The following procedures deal with the recovery of locks after a
202 * Reclaim all locks on server host. We do this by spawning a separate
206 nlmclnt_recovery(struct nlm_host *host)
208 struct task_struct *task;
210 if (!host->h_reclaiming++) {
212 task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
214 printk(KERN_ERR "lockd: unable to spawn reclaimer "
215 "thread. Locks for %s won't be reclaimed! "
216 "(%ld)\n", host->h_name, PTR_ERR(task));
223 struct nlm_host *host = (struct nlm_host *) ptr;
224 struct nlm_wait *block;
225 struct nlm_rqst *req;
226 struct file_lock *fl, *next;
228 struct net *net = host->net;
230 req = kmalloc(sizeof(*req), GFP_KERNEL);
234 allow_signal(SIGKILL);
236 down_write(&host->h_rwsem);
237 lockd_up(net, NULL); /* note: this cannot fail as lockd is already running */
239 dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
242 nsmstate = host->h_nsmstate;
244 /* Force a portmap getport - the peer's lockd will
245 * most likely end up on a different port.
247 host->h_nextrebind = jiffies;
248 nlm_rebind_host(host);
250 /* First, reclaim all locks that have been granted. */
251 list_splice_init(&host->h_granted, &host->h_reclaim);
252 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
253 list_del_init(&fl->fl_u.nfs_fl.list);
256 * sending this thread a SIGKILL will result in any unreclaimed
257 * locks being removed from the h_granted list. This means that
258 * the kernel will not attempt to reclaim them again if a new
259 * reclaimer thread is spawned for this host.
263 if (nlmclnt_reclaim(host, fl, req) != 0)
265 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
266 if (host->h_nsmstate != nsmstate) {
267 /* Argh! The server rebooted again! */
272 host->h_reclaiming = 0;
273 up_write(&host->h_rwsem);
274 dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
276 /* Now, wake up all processes that sleep on a blocked lock */
277 spin_lock(&nlm_blocked_lock);
278 list_for_each_entry(block, &nlm_blocked, b_list) {
279 if (block->b_host == host) {
280 block->b_status = nlm_lck_denied_grace_period;
281 wake_up(&block->b_wait);
284 spin_unlock(&nlm_blocked_lock);
286 /* Release host handle after use */
287 nlmclnt_release_host(host);