1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/lockd/svcsubs.c
4 *
5 * Various support routines for the NLM server.
6 *
7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
8 */
9
10#include <linux/types.h>
11#include <linux/string.h>
12#include <linux/time.h>
13#include <linux/in.h>
14#include <linux/slab.h>
15#include <linux/mutex.h>
16#include <linux/sunrpc/svc.h>
17#include <linux/sunrpc/addr.h>
18#include <linux/lockd/lockd.h>
19#include <linux/lockd/share.h>
20#include <linux/module.h>
21#include <linux/mount.h>
22#include <uapi/linux/nfs2.h>
23
24#define NLMDBG_FACILITY NLMDBG_SVCSUBS
25
26
27/*
28 * Global file hash table
29 */
30#define FILE_HASH_BITS 7
31#define FILE_NRHASH (1<<FILE_HASH_BITS)
32static struct hlist_head nlm_files[FILE_NRHASH];
33static DEFINE_MUTEX(nlm_file_mutex);
34
35#ifdef CONFIG_SUNRPC_DEBUG
36static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
37{
38 u32 *fhp = (u32*)f->data;
39
40 /* print the first 32 bytes of the fh */
41 dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
42 msg, fhp[0], fhp[1], fhp[2], fhp[3],
43 fhp[4], fhp[5], fhp[6], fhp[7]);
44}
45
46static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
47{
48 struct inode *inode = nlmsvc_file_inode(file);
49
50 dprintk("lockd: %s %s/%ld\n",
51 msg, inode->i_sb->s_id, inode->i_ino);
52}
53#else
54static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
55{
56 return;
57}
58
59static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
60{
61 return;
62}
63#endif
64
65static inline unsigned int file_hash(struct nfs_fh *f)
66{
67 unsigned int tmp=0;
68 int i;
69 for (i=0; i<NFS2_FHSIZE;i++)
70 tmp += f->data[i];
71 return tmp & (FILE_NRHASH - 1);
72}
73
74int lock_to_openmode(struct file_lock *lock)
75{
76 return lock_is_write(fl: lock) ? O_WRONLY : O_RDONLY;
77}
78
79/*
80 * Open the file. Note that if we're reexporting, for example,
81 * this could block the lockd thread for a while.
82 *
83 * We have to make sure we have the right credential to open
84 * the file.
85 */
86static __be32 nlm_do_fopen(struct svc_rqst *rqstp,
87 struct nlm_file *file, int mode)
88{
89 struct file **fp = &file->f_file[mode];
90 __be32 nfserr;
91
92 if (*fp)
93 return 0;
94 nfserr = nlmsvc_ops->fopen(rqstp, &file->f_handle, fp, mode);
95 if (nfserr)
96 dprintk("lockd: open failed (error %d)\n", nfserr);
97 return nfserr;
98}
99
100/*
101 * Lookup file info. If it doesn't exist, create a file info struct
102 * and open a (VFS) file for the given inode.
103 */
104__be32
105nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
106 struct nlm_lock *lock)
107{
108 struct nlm_file *file;
109 unsigned int hash;
110 __be32 nfserr;
111 int mode;
112
113 nlm_debug_print_fh(msg: "nlm_lookup_file", f: &lock->fh);
114
115 hash = file_hash(f: &lock->fh);
116 mode = lock_to_openmode(lock: &lock->fl);
117
118 /* Lock file table */
119 mutex_lock(lock: &nlm_file_mutex);
120
121 hlist_for_each_entry(file, &nlm_files[hash], f_list)
122 if (!nfs_compare_fh(a: &file->f_handle, b: &lock->fh)) {
123 mutex_lock(lock: &file->f_mutex);
124 nfserr = nlm_do_fopen(rqstp, file, mode);
125 mutex_unlock(lock: &file->f_mutex);
126 goto found;
127 }
128 nlm_debug_print_fh(msg: "creating file for", f: &lock->fh);
129
130 nfserr = nlm_lck_denied_nolocks;
131 file = kzalloc(sizeof(*file), GFP_KERNEL);
132 if (!file)
133 goto out_free;
134
135 memcpy(to: &file->f_handle, from: &lock->fh, len: sizeof(struct nfs_fh));
136 mutex_init(&file->f_mutex);
137 INIT_HLIST_NODE(h: &file->f_list);
138 INIT_LIST_HEAD(list: &file->f_blocks);
139
140 nfserr = nlm_do_fopen(rqstp, file, mode);
141 if (nfserr)
142 goto out_unlock;
143
144 hlist_add_head(n: &file->f_list, h: &nlm_files[hash]);
145
146found:
147 dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
148 *result = file;
149 file->f_count++;
150
151out_unlock:
152 mutex_unlock(lock: &nlm_file_mutex);
153 return nfserr;
154
155out_free:
156 kfree(objp: file);
157 goto out_unlock;
158}
159
160/*
161 * Delete a file after having released all locks, blocks and shares
162 */
163static inline void
164nlm_delete_file(struct nlm_file *file)
165{
166 nlm_debug_print_file(msg: "closing file", file);
167 if (!hlist_unhashed(h: &file->f_list)) {
168 hlist_del(n: &file->f_list);
169 if (file->f_file[O_RDONLY])
170 nlmsvc_ops->fclose(file->f_file[O_RDONLY]);
171 if (file->f_file[O_WRONLY])
172 nlmsvc_ops->fclose(file->f_file[O_WRONLY]);
173 kfree(objp: file);
174 } else {
175 printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
176 }
177}
178
179static int nlm_unlock_files(struct nlm_file *file, const struct file_lock *fl)
180{
181 struct file_lock lock;
182
183 locks_init_lock(&lock);
184 lock.c.flc_type = F_UNLCK;
185 lock.fl_start = 0;
186 lock.fl_end = OFFSET_MAX;
187 lock.c.flc_owner = fl->c.flc_owner;
188 lock.c.flc_pid = fl->c.flc_pid;
189 lock.c.flc_flags = FL_POSIX;
190
191 lock.c.flc_file = file->f_file[O_RDONLY];
192 if (lock.c.flc_file && vfs_lock_file(lock.c.flc_file, F_SETLK, &lock, NULL))
193 goto out_err;
194 lock.c.flc_file = file->f_file[O_WRONLY];
195 if (lock.c.flc_file && vfs_lock_file(lock.c.flc_file, F_SETLK, &lock, NULL))
196 goto out_err;
197 return 0;
198out_err:
199 pr_warn("lockd: unlock failure in %s:%d\n", __FILE__, __LINE__);
200 return 1;
201}
202
203/*
204 * Loop over all locks on the given file and perform the specified
205 * action.
206 */
207static int
208nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
209 nlm_host_match_fn_t match)
210{
211 struct inode *inode = nlmsvc_file_inode(file);
212 struct file_lock *fl;
213 struct file_lock_context *flctx = locks_inode_context(inode);
214 struct nlm_host *lockhost;
215
216 if (!flctx || list_empty_careful(head: &flctx->flc_posix))
217 return 0;
218again:
219 file->f_locks = 0;
220 spin_lock(lock: &flctx->flc_lock);
221 for_each_file_lock(fl, &flctx->flc_posix) {
222 if (fl->fl_lmops != &nlmsvc_lock_operations)
223 continue;
224
225 /* update current lock count */
226 file->f_locks++;
227
228 lockhost = ((struct nlm_lockowner *) fl->c.flc_owner)->host;
229 if (match(lockhost, host)) {
230
231 spin_unlock(lock: &flctx->flc_lock);
232 if (nlm_unlock_files(file, fl))
233 return 1;
234 goto again;
235 }
236 }
237 spin_unlock(lock: &flctx->flc_lock);
238
239 return 0;
240}
241
242static int
243nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
244{
245 return 1;
246}
247
248/*
249 * Inspect a single file
250 */
251static inline int
252nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
253{
254 nlmsvc_traverse_blocks(host, file, match);
255 nlmsvc_traverse_shares(host, file, match);
256 return nlm_traverse_locks(host, file, match);
257}
258
259/*
260 * Quick check whether there are still any locks, blocks or
261 * shares on a given file.
262 */
263static inline int
264nlm_file_inuse(struct nlm_file *file)
265{
266 struct inode *inode = nlmsvc_file_inode(file);
267 struct file_lock *fl;
268 struct file_lock_context *flctx = locks_inode_context(inode);
269
270 if (file->f_count || !list_empty(head: &file->f_blocks) || file->f_shares)
271 return 1;
272
273 if (flctx && !list_empty_careful(head: &flctx->flc_posix)) {
274 spin_lock(lock: &flctx->flc_lock);
275 for_each_file_lock(fl, &flctx->flc_posix) {
276 if (fl->fl_lmops == &nlmsvc_lock_operations) {
277 spin_unlock(lock: &flctx->flc_lock);
278 return 1;
279 }
280 }
281 spin_unlock(lock: &flctx->flc_lock);
282 }
283 file->f_locks = 0;
284 return 0;
285}
286
287static void nlm_close_files(struct nlm_file *file)
288{
289 if (file->f_file[O_RDONLY])
290 nlmsvc_ops->fclose(file->f_file[O_RDONLY]);
291 if (file->f_file[O_WRONLY])
292 nlmsvc_ops->fclose(file->f_file[O_WRONLY]);
293}
294
295/*
296 * Loop over all files in the file table.
297 */
298static int
299nlm_traverse_files(void *data, nlm_host_match_fn_t match,
300 int (*is_failover_file)(void *data, struct nlm_file *file))
301{
302 struct hlist_node *next;
303 struct nlm_file *file;
304 int i, ret = 0;
305
306 mutex_lock(lock: &nlm_file_mutex);
307 for (i = 0; i < FILE_NRHASH; i++) {
308 hlist_for_each_entry_safe(file, next, &nlm_files[i], f_list) {
309 if (is_failover_file && !is_failover_file(data, file))
310 continue;
311 file->f_count++;
312 mutex_unlock(lock: &nlm_file_mutex);
313
314 /* Traverse locks, blocks and shares of this file
315 * and update file->f_locks count */
316 if (nlm_inspect_file(host: data, file, match))
317 ret = 1;
318
319 mutex_lock(lock: &nlm_file_mutex);
320 file->f_count--;
321 /* No more references to this file. Let go of it. */
322 if (list_empty(head: &file->f_blocks) && !file->f_locks
323 && !file->f_shares && !file->f_count) {
324 hlist_del(n: &file->f_list);
325 nlm_close_files(file);
326 kfree(objp: file);
327 }
328 }
329 }
330 mutex_unlock(lock: &nlm_file_mutex);
331 return ret;
332}
333
334/*
335 * Release file. If there are no more remote locks on this file,
336 * close it and free the handle.
337 *
338 * Note that we can't do proper reference counting without major
339 * contortions because the code in fs/locks.c creates, deletes and
340 * splits locks without notification. Our only way is to walk the
341 * entire lock list each time we remove a lock.
342 */
343void
344nlm_release_file(struct nlm_file *file)
345{
346 dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
347 file, file->f_count);
348
349 /* Lock file table */
350 mutex_lock(lock: &nlm_file_mutex);
351
352 /* If there are no more locks etc, delete the file */
353 if (--file->f_count == 0 && !nlm_file_inuse(file))
354 nlm_delete_file(file);
355
356 mutex_unlock(lock: &nlm_file_mutex);
357}
358
359/*
360 * Helpers function for resource traversal
361 *
362 * nlmsvc_mark_host:
363 * used by the garbage collector; simply sets h_inuse only for those
364 * hosts, which passed network check.
365 * Always returns 0.
366 *
367 * nlmsvc_same_host:
368 * returns 1 iff the two hosts match. Used to release
369 * all resources bound to a specific host.
370 *
371 * nlmsvc_is_client:
372 * returns 1 iff the host is a client.
373 * Used by nlmsvc_invalidate_all
374 */
375
376static int
377nlmsvc_mark_host(void *data, struct nlm_host *hint)
378{
379 struct nlm_host *host = data;
380
381 if ((hint->net == NULL) ||
382 (host->net == hint->net))
383 host->h_inuse = 1;
384 return 0;
385}
386
387static int
388nlmsvc_same_host(void *data, struct nlm_host *other)
389{
390 struct nlm_host *host = data;
391
392 return host == other;
393}
394
395static int
396nlmsvc_is_client(void *data, struct nlm_host *dummy)
397{
398 struct nlm_host *host = data;
399
400 if (host->h_server) {
401 /* we are destroying locks even though the client
402 * hasn't asked us too, so don't unmonitor the
403 * client
404 */
405 if (host->h_nsmhandle)
406 host->h_nsmhandle->sm_sticky = 1;
407 return 1;
408 } else
409 return 0;
410}
411
412/*
413 * Mark all hosts that still hold resources
414 */
415void
416nlmsvc_mark_resources(struct net *net)
417{
418 struct nlm_host hint;
419
420 dprintk("lockd: %s for net %x\n", __func__, net ? net->ns.inum : 0);
421 hint.net = net;
422 nlm_traverse_files(data: &hint, match: nlmsvc_mark_host, NULL);
423}
424
425/*
426 * Release all resources held by the given client
427 */
428void
429nlmsvc_free_host_resources(struct nlm_host *host)
430{
431 dprintk("lockd: nlmsvc_free_host_resources\n");
432
433 if (nlm_traverse_files(data: host, match: nlmsvc_same_host, NULL)) {
434 printk(KERN_WARNING
435 "lockd: couldn't remove all locks held by %s\n",
436 host->h_name);
437 BUG();
438 }
439}
440
441/**
442 * nlmsvc_invalidate_all - remove all locks held for clients
443 *
444 * Release all locks held by NFS clients.
445 *
446 */
447void
448nlmsvc_invalidate_all(void)
449{
450 /*
451 * Previously, the code would call
452 * nlmsvc_free_host_resources for each client in
453 * turn, which is about as inefficient as it gets.
454 * Now we just do it once in nlm_traverse_files.
455 */
456 nlm_traverse_files(NULL, match: nlmsvc_is_client, NULL);
457}
458
459
460static int
461nlmsvc_match_sb(void *datap, struct nlm_file *file)
462{
463 struct super_block *sb = datap;
464
465 return sb == nlmsvc_file_inode(file)->i_sb;
466}
467
468/**
469 * nlmsvc_unlock_all_by_sb - release locks held on this file system
470 * @sb: super block
471 *
472 * Release all locks held by clients accessing this file system.
473 */
474int
475nlmsvc_unlock_all_by_sb(struct super_block *sb)
476{
477 int ret;
478
479 ret = nlm_traverse_files(data: sb, match: nlmsvc_always_match, is_failover_file: nlmsvc_match_sb);
480 return ret ? -EIO : 0;
481}
482EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
483
484static int
485nlmsvc_match_ip(void *datap, struct nlm_host *host)
486{
487 return rpc_cmp_addr(sap1: nlm_srcaddr(host), sap2: datap);
488}
489
490/**
491 * nlmsvc_unlock_all_by_ip - release local locks by IP address
492 * @server_addr: server's IP address as seen by clients
493 *
494 * Release all locks held by clients accessing this host
495 * via the passed in IP address.
496 */
497int
498nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
499{
500 int ret;
501
502 ret = nlm_traverse_files(data: server_addr, match: nlmsvc_match_ip, NULL);
503 return ret ? -EIO : 0;
504}
505EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
506