Root/fs/lockd/svcsubs.c

1/*
2 * linux/fs/lockd/svcsubs.c
3 *
4 * Various support routines for the NLM server.
5 *
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7 */
8
9#include <linux/types.h>
10#include <linux/string.h>
11#include <linux/time.h>
12#include <linux/in.h>
13#include <linux/slab.h>
14#include <linux/mutex.h>
15#include <linux/sunrpc/svc.h>
16#include <linux/sunrpc/clnt.h>
17#include <linux/nfsd/nfsfh.h>
18#include <linux/nfsd/export.h>
19#include <linux/lockd/lockd.h>
20#include <linux/lockd/share.h>
21#include <linux/module.h>
22#include <linux/mount.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 NFSD_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 = file->f_file->f_path.dentry->d_inode;
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
74/*
75 * Lookup file info. If it doesn't exist, create a file info struct
76 * and open a (VFS) file for the given inode.
77 *
78 * FIXME:
79 * Note that we open the file O_RDONLY even when creating write locks.
80 * This is not quite right, but for now, we assume the client performs
81 * the proper R/W checking.
82 */
83__be32
84nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
85                    struct nfs_fh *f)
86{
87    struct hlist_node *pos;
88    struct nlm_file *file;
89    unsigned int hash;
90    __be32 nfserr;
91
92    nlm_debug_print_fh("nlm_lookup_file", f);
93
94    hash = file_hash(f);
95
96    /* Lock file table */
97    mutex_lock(&nlm_file_mutex);
98
99    hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
100        if (!nfs_compare_fh(&file->f_handle, f))
101            goto found;
102
103    nlm_debug_print_fh("creating file for", f);
104
105    nfserr = nlm_lck_denied_nolocks;
106    file = kzalloc(sizeof(*file), GFP_KERNEL);
107    if (!file)
108        goto out_unlock;
109
110    memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
111    mutex_init(&file->f_mutex);
112    INIT_HLIST_NODE(&file->f_list);
113    INIT_LIST_HEAD(&file->f_blocks);
114
115    /* Open the file. Note that this must not sleep for too long, else
116     * we would lock up lockd:-) So no NFS re-exports, folks.
117     *
118     * We have to make sure we have the right credential to open
119     * the file.
120     */
121    if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
122        dprintk("lockd: open failed (error %d)\n", nfserr);
123        goto out_free;
124    }
125
126    hlist_add_head(&file->f_list, &nlm_files[hash]);
127
128found:
129    dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
130    *result = file;
131    file->f_count++;
132    nfserr = 0;
133
134out_unlock:
135    mutex_unlock(&nlm_file_mutex);
136    return nfserr;
137
138out_free:
139    kfree(file);
140    goto out_unlock;
141}
142
143/*
144 * Delete a file after having released all locks, blocks and shares
145 */
146static inline void
147nlm_delete_file(struct nlm_file *file)
148{
149    nlm_debug_print_file("closing file", file);
150    if (!hlist_unhashed(&file->f_list)) {
151        hlist_del(&file->f_list);
152        nlmsvc_ops->fclose(file->f_file);
153        kfree(file);
154    } else {
155        printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
156    }
157}
158
159/*
160 * Loop over all locks on the given file and perform the specified
161 * action.
162 */
163static int
164nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
165            nlm_host_match_fn_t match)
166{
167    struct inode *inode = nlmsvc_file_inode(file);
168    struct file_lock *fl;
169    struct nlm_host *lockhost;
170
171again:
172    file->f_locks = 0;
173    lock_flocks(); /* protects i_flock list */
174    for (fl = inode->i_flock; fl; fl = fl->fl_next) {
175        if (fl->fl_lmops != &nlmsvc_lock_operations)
176            continue;
177
178        /* update current lock count */
179        file->f_locks++;
180
181        lockhost = (struct nlm_host *) fl->fl_owner;
182        if (match(lockhost, host)) {
183            struct file_lock lock = *fl;
184
185            unlock_flocks();
186            lock.fl_type = F_UNLCK;
187            lock.fl_start = 0;
188            lock.fl_end = OFFSET_MAX;
189            if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
190                printk("lockd: unlock failure in %s:%d\n",
191                        __FILE__, __LINE__);
192                return 1;
193            }
194            goto again;
195        }
196    }
197    unlock_flocks();
198
199    return 0;
200}
201
202static int
203nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
204{
205    return 1;
206}
207
208/*
209 * Inspect a single file
210 */
211static inline int
212nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
213{
214    nlmsvc_traverse_blocks(host, file, match);
215    nlmsvc_traverse_shares(host, file, match);
216    return nlm_traverse_locks(host, file, match);
217}
218
219/*
220 * Quick check whether there are still any locks, blocks or
221 * shares on a given file.
222 */
223static inline int
224nlm_file_inuse(struct nlm_file *file)
225{
226    struct inode *inode = nlmsvc_file_inode(file);
227    struct file_lock *fl;
228
229    if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
230        return 1;
231
232    lock_flocks();
233    for (fl = inode->i_flock; fl; fl = fl->fl_next) {
234        if (fl->fl_lmops == &nlmsvc_lock_operations) {
235            unlock_flocks();
236            return 1;
237        }
238    }
239    unlock_flocks();
240    file->f_locks = 0;
241    return 0;
242}
243
244/*
245 * Loop over all files in the file table.
246 */
247static int
248nlm_traverse_files(void *data, nlm_host_match_fn_t match,
249        int (*is_failover_file)(void *data, struct nlm_file *file))
250{
251    struct hlist_node *pos, *next;
252    struct nlm_file *file;
253    int i, ret = 0;
254
255    mutex_lock(&nlm_file_mutex);
256    for (i = 0; i < FILE_NRHASH; i++) {
257        hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
258            if (is_failover_file && !is_failover_file(data, file))
259                continue;
260            file->f_count++;
261            mutex_unlock(&nlm_file_mutex);
262
263            /* Traverse locks, blocks and shares of this file
264             * and update file->f_locks count */
265            if (nlm_inspect_file(data, file, match))
266                ret = 1;
267
268            mutex_lock(&nlm_file_mutex);
269            file->f_count--;
270            /* No more references to this file. Let go of it. */
271            if (list_empty(&file->f_blocks) && !file->f_locks
272             && !file->f_shares && !file->f_count) {
273                hlist_del(&file->f_list);
274                nlmsvc_ops->fclose(file->f_file);
275                kfree(file);
276            }
277        }
278    }
279    mutex_unlock(&nlm_file_mutex);
280    return ret;
281}
282
283/*
284 * Release file. If there are no more remote locks on this file,
285 * close it and free the handle.
286 *
287 * Note that we can't do proper reference counting without major
288 * contortions because the code in fs/locks.c creates, deletes and
289 * splits locks without notification. Our only way is to walk the
290 * entire lock list each time we remove a lock.
291 */
292void
293nlm_release_file(struct nlm_file *file)
294{
295    dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
296                file, file->f_count);
297
298    /* Lock file table */
299    mutex_lock(&nlm_file_mutex);
300
301    /* If there are no more locks etc, delete the file */
302    if (--file->f_count == 0 && !nlm_file_inuse(file))
303        nlm_delete_file(file);
304
305    mutex_unlock(&nlm_file_mutex);
306}
307
308/*
309 * Helpers function for resource traversal
310 *
311 * nlmsvc_mark_host:
312 * used by the garbage collector; simply sets h_inuse.
313 * Always returns 0.
314 *
315 * nlmsvc_same_host:
316 * returns 1 iff the two hosts match. Used to release
317 * all resources bound to a specific host.
318 *
319 * nlmsvc_is_client:
320 * returns 1 iff the host is a client.
321 * Used by nlmsvc_invalidate_all
322 */
323static int
324nlmsvc_mark_host(void *data, struct nlm_host *dummy)
325{
326    struct nlm_host *host = data;
327
328    host->h_inuse = 1;
329    return 0;
330}
331
332static int
333nlmsvc_same_host(void *data, struct nlm_host *other)
334{
335    struct nlm_host *host = data;
336
337    return host == other;
338}
339
340static int
341nlmsvc_is_client(void *data, struct nlm_host *dummy)
342{
343    struct nlm_host *host = data;
344
345    if (host->h_server) {
346        /* we are destroying locks even though the client
347         * hasn't asked us too, so don't unmonitor the
348         * client
349         */
350        if (host->h_nsmhandle)
351            host->h_nsmhandle->sm_sticky = 1;
352        return 1;
353    } else
354        return 0;
355}
356
357/*
358 * Mark all hosts that still hold resources
359 */
360void
361nlmsvc_mark_resources(void)
362{
363    dprintk("lockd: nlmsvc_mark_resources\n");
364    nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
365}
366
367/*
368 * Release all resources held by the given client
369 */
370void
371nlmsvc_free_host_resources(struct nlm_host *host)
372{
373    dprintk("lockd: nlmsvc_free_host_resources\n");
374
375    if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
376        printk(KERN_WARNING
377            "lockd: couldn't remove all locks held by %s\n",
378            host->h_name);
379        BUG();
380    }
381}
382
383/**
384 * nlmsvc_invalidate_all - remove all locks held for clients
385 *
386 * Release all locks held by NFS clients.
387 *
388 */
389void
390nlmsvc_invalidate_all(void)
391{
392    /*
393     * Previously, the code would call
394     * nlmsvc_free_host_resources for each client in
395     * turn, which is about as inefficient as it gets.
396     * Now we just do it once in nlm_traverse_files.
397     */
398    nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
399}
400
401static int
402nlmsvc_match_sb(void *datap, struct nlm_file *file)
403{
404    struct super_block *sb = datap;
405
406    return sb == file->f_file->f_path.mnt->mnt_sb;
407}
408
409/**
410 * nlmsvc_unlock_all_by_sb - release locks held on this file system
411 * @sb: super block
412 *
413 * Release all locks held by clients accessing this file system.
414 */
415int
416nlmsvc_unlock_all_by_sb(struct super_block *sb)
417{
418    int ret;
419
420    ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
421    return ret ? -EIO : 0;
422}
423EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
424
425static int
426nlmsvc_match_ip(void *datap, struct nlm_host *host)
427{
428    return rpc_cmp_addr(nlm_srcaddr(host), datap);
429}
430
431/**
432 * nlmsvc_unlock_all_by_ip - release local locks by IP address
433 * @server_addr: server's IP address as seen by clients
434 *
435 * Release all locks held by clients accessing this host
436 * via the passed in IP address.
437 */
438int
439nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
440{
441    int ret;
442
443    ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
444    return ret ? -EIO : 0;
445}
446EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
447

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