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/config.h>
10 #include <linux/types.h>
11 #include <linux/string.h>
12 #include <linux/time.h>
13 #include <linux/in.h>
14 #include <linux/sunrpc/svc.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/nfsd/nfsfh.h>
17 #include <linux/nfsd/export.h>
18 #include <linux/lockd/lockd.h>
19 #include <linux/lockd/share.h>
20 #include <linux/lockd/sm_inter.h>
21
22 #define NLMDBG_FACILITY NLMDBG_SVCSUBS
23
24
25 /*
26 * Global file hash table
27 */
28 #define FILE_HASH_BITS 5
29 #define FILE_NRHASH (1<<FILE_HASH_BITS)
30 static struct nlm_file * nlm_files[FILE_NRHASH];
31 static DECLARE_MUTEX(nlm_file_sema);
32
33 static inline unsigned int file_hash(struct nfs_fh *f)
34 {
35 unsigned int tmp=0;
36 int i;
37 for (i=0; i<NFS2_FHSIZE;i++)
38 tmp += f->data[i];
39 return tmp & (FILE_NRHASH - 1);
40 }
41
42 /*
43 * Lookup file info. If it doesn't exist, create a file info struct
44 * and open a (VFS) file for the given inode.
45 *
46 * FIXME:
47 * Note that we open the file O_RDONLY even when creating write locks.
48 * This is not quite right, but for now, we assume the client performs
49 * the proper R/W checking.
50 */
51 u32
52 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
53 struct nfs_fh *f)
54 {
55 struct nlm_file *file;
56 unsigned int hash;
57 u32 nfserr;
58 u32 *fhp = (u32*)f->data;
59
60 dprintk("lockd: nlm_file_lookup(%08x %08x %08x %08x %08x %08x)\n",
61 fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5]);
62
63
64 hash = file_hash(f);
65
66 /* Lock file table */
67 down(&nlm_file_sema);
68
69 for (file = nlm_files[hash]; file; file = file->f_next)
70 if (!nfs_compare_fh(&file->f_handle, f))
71 goto found;
72
73 dprintk("lockd: creating file for (%08x %08x %08x %08x %08x %08x)\n",
74 fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5]);
75
76 nfserr = nlm_lck_denied_nolocks;
77 file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL);
78 if (!file)
79 goto out_unlock;
80
81 memset(file, 0, sizeof(*file));
82 memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
83 file->f_hash = hash;
84 init_MUTEX(&file->f_sema);
85
86 /* Open the file. Note that this must not sleep for too long, else
87 * we would lock up lockd:-) So no NFS re-exports, folks.
88 *
89 * We have to make sure we have the right credential to open
90 * the file.
91 */
92 if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
93 dprintk("lockd: open failed (nfserr %d)\n", ntohl(nfserr));
94 goto out_free;
95 }
96
97 file->f_next = nlm_files[hash];
98 nlm_files[hash] = file;
99
100 found:
101 dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
102 *result = file;
103 file->f_count++;
104 nfserr = 0;
105
106 out_unlock:
107 up(&nlm_file_sema);
108 return nfserr;
109
110 out_free:
111 kfree(file);
112 #ifdef CONFIG_LOCKD_V4
113 if (nfserr == 1)
114 nfserr = nlm4_stale_fh;
115 else
116 #endif
117 nfserr = nlm_lck_denied;
118 goto out_unlock;
119 }
120
121 /*
122 * Delete a file after having released all locks, blocks and shares
123 */
124 static inline void
125 nlm_delete_file(struct nlm_file *file)
126 {
127 struct inode *inode = file->f_file->f_dentry->d_inode;
128 struct nlm_file **fp, *f;
129
130 dprintk("lockd: closing file %s/%ld\n",
131 inode->i_sb->s_id, inode->i_ino);
132 fp = nlm_files + file->f_hash;
133 while ((f = *fp) != NULL) {
134 if (f == file) {
135 *fp = file->f_next;
136 nlmsvc_ops->fclose(file->f_file);
137 kfree(file);
138 return;
139 }
140 fp = &f->f_next;
141 }
142
143 printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
144 }
145
146 /*
147 * Loop over all locks on the given file and perform the specified
148 * action.
149 */
150 static int
151 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
152 {
153 struct inode *inode = nlmsvc_file_inode(file);
154 struct file_lock *fl;
155 struct nlm_host *lockhost;
156
157 again:
158 file->f_locks = 0;
159 for (fl = inode->i_flock; fl; fl = fl->fl_next) {
160 if (!(fl->fl_flags & FL_LOCKD))
161 continue;
162
163 /* update current lock count */
164 file->f_locks++;
165 lockhost = (struct nlm_host *) fl->fl_owner;
166 if (action == NLM_ACT_MARK)
167 lockhost->h_inuse = 1;
168 else if (action == NLM_ACT_CHECK)
169 return 1;
170 else if (action == NLM_ACT_UNLOCK) {
171 struct file_lock lock = *fl;
172
173 if (host && lockhost != host)
174 continue;
175
176 lock.fl_type = F_UNLCK;
177 lock.fl_start = 0;
178 lock.fl_end = OFFSET_MAX;
179 if (posix_lock_file(file->f_file, &lock) < 0) {
180 printk("lockd: unlock failure in %s:%d\n",
181 __FILE__, __LINE__);
182 return 1;
183 }
184 goto again;
185 }
186 }
187
188 return 0;
189 }
190
191 /*
192 * Operate on a single file
193 */
194 static inline int
195 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
196 {
197 if (action == NLM_ACT_CHECK) {
198 /* Fast path for mark and sweep garbage collection */
199 if (file->f_count || file->f_blocks || file->f_shares)
200 return 1;
201 } else {
202 if (nlmsvc_traverse_blocks(host, file, action)
203 || nlmsvc_traverse_shares(host, file, action))
204 return 1;
205 }
206 return nlm_traverse_locks(host, file, action);
207 }
208
209 /*
210 * Loop over all files in the file table.
211 */
212 static int
213 nlm_traverse_files(struct nlm_host *host, int action)
214 {
215 struct nlm_file *file, **fp;
216 int i;
217
218 down(&nlm_file_sema);
219 for (i = 0; i < FILE_NRHASH; i++) {
220 fp = nlm_files + i;
221 while ((file = *fp) != NULL) {
222 /* Traverse locks, blocks and shares of this file
223 * and update file->f_locks count */
224 if (nlm_inspect_file(host, file, action)) {
225 up(&nlm_file_sema);
226 return 1;
227 }
228
229 /* No more references to this file. Let go of it. */
230 if (!file->f_blocks && !file->f_locks
231 && !file->f_shares && !file->f_count) {
232 *fp = file->f_next;
233 nlmsvc_ops->fclose(file->f_file);
234 kfree(file);
235 } else {
236 fp = &file->f_next;
237 }
238 }
239 }
240 up(&nlm_file_sema);
241 return 0;
242 }
243
244 /*
245 * Release file. If there are no more remote locks on this file,
246 * close it and free the handle.
247 *
248 * Note that we can't do proper reference counting without major
249 * contortions because the code in fs/locks.c creates, deletes and
250 * splits locks without notification. Our only way is to walk the
251 * entire lock list each time we remove a lock.
252 */
253 void
254 nlm_release_file(struct nlm_file *file)
255 {
256 dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
257 file, file->f_count);
258
259 /* Lock file table */
260 down(&nlm_file_sema);
261
262 /* If there are no more locks etc, delete the file */
263 if(--file->f_count == 0) {
264 if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
265 nlm_delete_file(file);
266 }
267
268 up(&nlm_file_sema);
269 }
270
271 /*
272 * Mark all hosts that still hold resources
273 */
274 void
275 nlmsvc_mark_resources(void)
276 {
277 dprintk("lockd: nlmsvc_mark_resources\n");
278
279 nlm_traverse_files(NULL, NLM_ACT_MARK);
280 }
281
282 /*
283 * Release all resources held by the given client
284 */
285 void
286 nlmsvc_free_host_resources(struct nlm_host *host)
287 {
288 dprintk("lockd: nlmsvc_free_host_resources\n");
289
290 if (nlm_traverse_files(host, NLM_ACT_UNLOCK))
291 printk(KERN_WARNING
292 "lockd: couldn't remove all locks held by %s",
293 host->h_name);
294 }
295
296 /*
297 * delete all hosts structs for clients
298 */
299 void
300 nlmsvc_invalidate_all(void)
301 {
302 struct nlm_host *host;
303 while ((host = nlm_find_client()) != NULL) {
304 nlmsvc_free_host_resources(host);
305 host->h_expires = 0;
306 host->h_killed = 1;
307 nlm_release_host(host);
308 }
309 }
310
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