xref: /openbmc/linux/fs/lockd/svcsubs.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 #ifdef NFSD_DEBUG
34 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
35 {
36 	u32 *fhp = (u32*)f->data;
37 
38 	/* print the first 32 bytes of the fh */
39 	dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
40 		msg, fhp[0], fhp[1], fhp[2], fhp[3],
41 		fhp[4], fhp[5], fhp[6], fhp[7]);
42 }
43 
44 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
45 {
46 	struct inode *inode = file->f_file->f_dentry->d_inode;
47 
48 	dprintk("lockd: %s %s/%ld\n",
49 		msg, inode->i_sb->s_id, inode->i_ino);
50 }
51 #else
52 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
53 {
54 	return;
55 }
56 
57 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
58 {
59 	return;
60 }
61 #endif
62 
63 static inline unsigned int file_hash(struct nfs_fh *f)
64 {
65 	unsigned int tmp=0;
66 	int i;
67 	for (i=0; i<NFS2_FHSIZE;i++)
68 		tmp += f->data[i];
69 	return tmp & (FILE_NRHASH - 1);
70 }
71 
72 /*
73  * Lookup file info. If it doesn't exist, create a file info struct
74  * and open a (VFS) file for the given inode.
75  *
76  * FIXME:
77  * Note that we open the file O_RDONLY even when creating write locks.
78  * This is not quite right, but for now, we assume the client performs
79  * the proper R/W checking.
80  */
81 u32
82 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
83 					struct nfs_fh *f)
84 {
85 	struct nlm_file	*file;
86 	unsigned int	hash;
87 	u32		nfserr;
88 
89 	nlm_debug_print_fh("nlm_file_lookup", f);
90 
91 	hash = file_hash(f);
92 
93 	/* Lock file table */
94 	down(&nlm_file_sema);
95 
96 	for (file = nlm_files[hash]; file; file = file->f_next)
97 		if (!nfs_compare_fh(&file->f_handle, f))
98 			goto found;
99 
100 	nlm_debug_print_fh("creating file for", f);
101 
102 	nfserr = nlm_lck_denied_nolocks;
103 	file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL);
104 	if (!file)
105 		goto out_unlock;
106 
107 	memset(file, 0, sizeof(*file));
108 	memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
109 	file->f_hash = hash;
110 	init_MUTEX(&file->f_sema);
111 
112 	/* Open the file. Note that this must not sleep for too long, else
113 	 * we would lock up lockd:-) So no NFS re-exports, folks.
114 	 *
115 	 * We have to make sure we have the right credential to open
116 	 * the file.
117 	 */
118 	if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
119 		dprintk("lockd: open failed (nfserr %d)\n", ntohl(nfserr));
120 		goto out_free;
121 	}
122 
123 	file->f_next = nlm_files[hash];
124 	nlm_files[hash] = file;
125 
126 found:
127 	dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
128 	*result = file;
129 	file->f_count++;
130 	nfserr = 0;
131 
132 out_unlock:
133 	up(&nlm_file_sema);
134 	return nfserr;
135 
136 out_free:
137 	kfree(file);
138 #ifdef CONFIG_LOCKD_V4
139 	if (nfserr == 1)
140 		nfserr = nlm4_stale_fh;
141 	else
142 #endif
143 	nfserr = nlm_lck_denied;
144 	goto out_unlock;
145 }
146 
147 /*
148  * Delete a file after having released all locks, blocks and shares
149  */
150 static inline void
151 nlm_delete_file(struct nlm_file *file)
152 {
153 	struct nlm_file	**fp, *f;
154 
155 	nlm_debug_print_file("closing file", file);
156 
157 	fp = nlm_files + file->f_hash;
158 	while ((f = *fp) != NULL) {
159 		if (f == file) {
160 			*fp = file->f_next;
161 			nlmsvc_ops->fclose(file->f_file);
162 			kfree(file);
163 			return;
164 		}
165 		fp = &f->f_next;
166 	}
167 
168 	printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
169 }
170 
171 /*
172  * Loop over all locks on the given file and perform the specified
173  * action.
174  */
175 static int
176 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
177 {
178 	struct inode	 *inode = nlmsvc_file_inode(file);
179 	struct file_lock *fl;
180 	struct nlm_host	 *lockhost;
181 
182 again:
183 	file->f_locks = 0;
184 	for (fl = inode->i_flock; fl; fl = fl->fl_next) {
185 		if (!(fl->fl_flags & FL_LOCKD))
186 			continue;
187 
188 		/* update current lock count */
189 		file->f_locks++;
190 		lockhost = (struct nlm_host *) fl->fl_owner;
191 		if (action == NLM_ACT_MARK)
192 			lockhost->h_inuse = 1;
193 		else if (action == NLM_ACT_CHECK)
194 			return 1;
195 		else if (action == NLM_ACT_UNLOCK) {
196 			struct file_lock lock = *fl;
197 
198 			if (host && lockhost != host)
199 				continue;
200 
201 			lock.fl_type  = F_UNLCK;
202 			lock.fl_start = 0;
203 			lock.fl_end   = OFFSET_MAX;
204 			if (posix_lock_file(file->f_file, &lock) < 0) {
205 				printk("lockd: unlock failure in %s:%d\n",
206 						__FILE__, __LINE__);
207 				return 1;
208 			}
209 			goto again;
210 		}
211 	}
212 
213 	return 0;
214 }
215 
216 /*
217  * Operate on a single file
218  */
219 static inline int
220 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
221 {
222 	if (action == NLM_ACT_CHECK) {
223 		/* Fast path for mark and sweep garbage collection */
224 		if (file->f_count || file->f_blocks || file->f_shares)
225 			return 1;
226 	} else {
227 		if (nlmsvc_traverse_blocks(host, file, action)
228 		 || nlmsvc_traverse_shares(host, file, action))
229 			return 1;
230 	}
231 	return nlm_traverse_locks(host, file, action);
232 }
233 
234 /*
235  * Loop over all files in the file table.
236  */
237 static int
238 nlm_traverse_files(struct nlm_host *host, int action)
239 {
240 	struct nlm_file	*file, **fp;
241 	int		i;
242 
243 	down(&nlm_file_sema);
244 	for (i = 0; i < FILE_NRHASH; i++) {
245 		fp = nlm_files + i;
246 		while ((file = *fp) != NULL) {
247 			/* Traverse locks, blocks and shares of this file
248 			 * and update file->f_locks count */
249 			if (nlm_inspect_file(host, file, action)) {
250 				up(&nlm_file_sema);
251 				return 1;
252 			}
253 
254 			/* No more references to this file. Let go of it. */
255 			if (!file->f_blocks && !file->f_locks
256 			 && !file->f_shares && !file->f_count) {
257 				*fp = file->f_next;
258 				nlmsvc_ops->fclose(file->f_file);
259 				kfree(file);
260 			} else {
261 				fp = &file->f_next;
262 			}
263 		}
264 	}
265 	up(&nlm_file_sema);
266 	return 0;
267 }
268 
269 /*
270  * Release file. If there are no more remote locks on this file,
271  * close it and free the handle.
272  *
273  * Note that we can't do proper reference counting without major
274  * contortions because the code in fs/locks.c creates, deletes and
275  * splits locks without notification. Our only way is to walk the
276  * entire lock list each time we remove a lock.
277  */
278 void
279 nlm_release_file(struct nlm_file *file)
280 {
281 	dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
282 				file, file->f_count);
283 
284 	/* Lock file table */
285 	down(&nlm_file_sema);
286 
287 	/* If there are no more locks etc, delete the file */
288 	if(--file->f_count == 0) {
289 		if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
290 			nlm_delete_file(file);
291 	}
292 
293 	up(&nlm_file_sema);
294 }
295 
296 /*
297  * Mark all hosts that still hold resources
298  */
299 void
300 nlmsvc_mark_resources(void)
301 {
302 	dprintk("lockd: nlmsvc_mark_resources\n");
303 
304 	nlm_traverse_files(NULL, NLM_ACT_MARK);
305 }
306 
307 /*
308  * Release all resources held by the given client
309  */
310 void
311 nlmsvc_free_host_resources(struct nlm_host *host)
312 {
313 	dprintk("lockd: nlmsvc_free_host_resources\n");
314 
315 	if (nlm_traverse_files(host, NLM_ACT_UNLOCK))
316 		printk(KERN_WARNING
317 			"lockd: couldn't remove all locks held by %s",
318 			host->h_name);
319 }
320 
321 /*
322  * delete all hosts structs for clients
323  */
324 void
325 nlmsvc_invalidate_all(void)
326 {
327 	struct nlm_host *host;
328 	while ((host = nlm_find_client()) != NULL) {
329 		nlmsvc_free_host_resources(host);
330 		host->h_expires = 0;
331 		host->h_killed = 1;
332 		nlm_release_host(host);
333 	}
334 }
335