usb: typec: intel_pmc_mux: Add support for USB4
[linux/fpc-iii.git] / fs / lockd / clntlock.c
bloba5bb3f721a9d4babd4b6aa6236f7e2ca05815605
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
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>
8 */
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/lockd/lockd.h>
18 #include <linux/kthread.h>
20 #define NLMDBG_FACILITY NLMDBG_CLIENT
23 * Local function prototypes
25 static int reclaimer(void *ptr);
28 * The following functions handle blocking and granting from the
29 * client perspective.
33 * This is the representation of a blocked client lock.
35 struct nlm_wait {
36 struct list_head b_list; /* linked list */
37 wait_queue_head_t b_wait; /* where to wait on */
38 struct nlm_host * b_host;
39 struct file_lock * b_lock; /* local file lock */
40 unsigned short b_reclaim; /* got to reclaim lock */
41 __be32 b_status; /* grant callback status */
44 static LIST_HEAD(nlm_blocked);
45 static DEFINE_SPINLOCK(nlm_blocked_lock);
47 /**
48 * nlmclnt_init - Set up per-NFS mount point lockd data structures
49 * @nlm_init: pointer to arguments structure
51 * Returns pointer to an appropriate nlm_host struct,
52 * or an ERR_PTR value.
54 struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
56 struct nlm_host *host;
57 u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
58 int status;
60 status = lockd_up(nlm_init->net, nlm_init->cred);
61 if (status < 0)
62 return ERR_PTR(status);
64 host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
65 nlm_init->protocol, nlm_version,
66 nlm_init->hostname, nlm_init->noresvport,
67 nlm_init->net, nlm_init->cred);
68 if (host == NULL)
69 goto out_nohost;
70 if (host->h_rpcclnt == NULL && nlm_bind_host(host) == NULL)
71 goto out_nobind;
73 host->h_nlmclnt_ops = nlm_init->nlmclnt_ops;
74 return host;
75 out_nobind:
76 nlmclnt_release_host(host);
77 out_nohost:
78 lockd_down(nlm_init->net);
79 return ERR_PTR(-ENOLCK);
81 EXPORT_SYMBOL_GPL(nlmclnt_init);
83 /**
84 * nlmclnt_done - Release resources allocated by nlmclnt_init()
85 * @host: nlm_host structure reserved by nlmclnt_init()
88 void nlmclnt_done(struct nlm_host *host)
90 struct net *net = host->net;
92 nlmclnt_release_host(host);
93 lockd_down(net);
95 EXPORT_SYMBOL_GPL(nlmclnt_done);
98 * Queue up a lock for blocking so that the GRANTED request can see it
100 struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
102 struct nlm_wait *block;
104 block = kmalloc(sizeof(*block), GFP_KERNEL);
105 if (block != NULL) {
106 block->b_host = host;
107 block->b_lock = fl;
108 init_waitqueue_head(&block->b_wait);
109 block->b_status = nlm_lck_blocked;
111 spin_lock(&nlm_blocked_lock);
112 list_add(&block->b_list, &nlm_blocked);
113 spin_unlock(&nlm_blocked_lock);
115 return block;
118 void nlmclnt_finish_block(struct nlm_wait *block)
120 if (block == NULL)
121 return;
122 spin_lock(&nlm_blocked_lock);
123 list_del(&block->b_list);
124 spin_unlock(&nlm_blocked_lock);
125 kfree(block);
129 * Block on a lock
131 int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
133 long ret;
135 /* A borken server might ask us to block even if we didn't
136 * request it. Just say no!
138 if (block == NULL)
139 return -EAGAIN;
141 /* Go to sleep waiting for GRANT callback. Some servers seem
142 * to lose callbacks, however, so we're going to poll from
143 * time to time just to make sure.
145 * For now, the retry frequency is pretty high; normally
146 * a 1 minute timeout would do. See the comment before
147 * nlmclnt_lock for an explanation.
149 ret = wait_event_interruptible_timeout(block->b_wait,
150 block->b_status != nlm_lck_blocked,
151 timeout);
152 if (ret < 0)
153 return -ERESTARTSYS;
154 /* Reset the lock status after a server reboot so we resend */
155 if (block->b_status == nlm_lck_denied_grace_period)
156 block->b_status = nlm_lck_blocked;
157 req->a_res.status = block->b_status;
158 return 0;
162 * The server lockd has called us back to tell us the lock was granted
164 __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
166 const struct file_lock *fl = &lock->fl;
167 const struct nfs_fh *fh = &lock->fh;
168 struct nlm_wait *block;
169 __be32 res = nlm_lck_denied;
172 * Look up blocked request based on arguments.
173 * Warning: must not use cookie to match it!
175 spin_lock(&nlm_blocked_lock);
176 list_for_each_entry(block, &nlm_blocked, b_list) {
177 struct file_lock *fl_blocked = block->b_lock;
179 if (fl_blocked->fl_start != fl->fl_start)
180 continue;
181 if (fl_blocked->fl_end != fl->fl_end)
182 continue;
184 * Careful! The NLM server will return the 32-bit "pid" that
185 * we put on the wire: in this case the lockowner "pid".
187 if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
188 continue;
189 if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
190 continue;
191 if (nfs_compare_fh(NFS_FH(locks_inode(fl_blocked->fl_file)), fh) != 0)
192 continue;
193 /* Alright, we found a lock. Set the return status
194 * and wake up the caller
196 block->b_status = nlm_granted;
197 wake_up(&block->b_wait);
198 res = nlm_granted;
200 spin_unlock(&nlm_blocked_lock);
201 return res;
205 * The following procedures deal with the recovery of locks after a
206 * server crash.
210 * Reclaim all locks on server host. We do this by spawning a separate
211 * reclaimer thread.
213 void
214 nlmclnt_recovery(struct nlm_host *host)
216 struct task_struct *task;
218 if (!host->h_reclaiming++) {
219 nlm_get_host(host);
220 task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
221 if (IS_ERR(task))
222 printk(KERN_ERR "lockd: unable to spawn reclaimer "
223 "thread. Locks for %s won't be reclaimed! "
224 "(%ld)\n", host->h_name, PTR_ERR(task));
228 static int
229 reclaimer(void *ptr)
231 struct nlm_host *host = (struct nlm_host *) ptr;
232 struct nlm_wait *block;
233 struct nlm_rqst *req;
234 struct file_lock *fl, *next;
235 u32 nsmstate;
236 struct net *net = host->net;
238 req = kmalloc(sizeof(*req), GFP_KERNEL);
239 if (!req)
240 return 0;
242 allow_signal(SIGKILL);
244 down_write(&host->h_rwsem);
245 lockd_up(net, NULL); /* note: this cannot fail as lockd is already running */
247 dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
249 restart:
250 nsmstate = host->h_nsmstate;
252 /* Force a portmap getport - the peer's lockd will
253 * most likely end up on a different port.
255 host->h_nextrebind = jiffies;
256 nlm_rebind_host(host);
258 /* First, reclaim all locks that have been granted. */
259 list_splice_init(&host->h_granted, &host->h_reclaim);
260 list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
261 list_del_init(&fl->fl_u.nfs_fl.list);
264 * sending this thread a SIGKILL will result in any unreclaimed
265 * locks being removed from the h_granted list. This means that
266 * the kernel will not attempt to reclaim them again if a new
267 * reclaimer thread is spawned for this host.
269 if (signalled())
270 continue;
271 if (nlmclnt_reclaim(host, fl, req) != 0)
272 continue;
273 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
274 if (host->h_nsmstate != nsmstate) {
275 /* Argh! The server rebooted again! */
276 goto restart;
280 host->h_reclaiming = 0;
281 up_write(&host->h_rwsem);
282 dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
284 /* Now, wake up all processes that sleep on a blocked lock */
285 spin_lock(&nlm_blocked_lock);
286 list_for_each_entry(block, &nlm_blocked, b_list) {
287 if (block->b_host == host) {
288 block->b_status = nlm_lck_denied_grace_period;
289 wake_up(&block->b_wait);
292 spin_unlock(&nlm_blocked_lock);
294 /* Release host handle after use */
295 nlmclnt_release_host(host);
296 lockd_down(net);
297 kfree(req);
298 return 0;