svcsubs.c 8.4 KB

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  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. #include <linux/types.h>
  9. #include <linux/string.h>
  10. #include <linux/time.h>
  11. #include <linux/in.h>
  12. #include <linux/mutex.h>
  13. #include <linux/sunrpc/svc.h>
  14. #include <linux/sunrpc/clnt.h>
  15. #include <linux/nfsd/nfsfh.h>
  16. #include <linux/nfsd/export.h>
  17. #include <linux/lockd/lockd.h>
  18. #include <linux/lockd/share.h>
  19. #include <linux/lockd/sm_inter.h>
  20. #define NLMDBG_FACILITY NLMDBG_SVCSUBS
  21. /*
  22. * Global file hash table
  23. */
  24. #define FILE_HASH_BITS 7
  25. #define FILE_NRHASH (1<<FILE_HASH_BITS)
  26. static struct hlist_head nlm_files[FILE_NRHASH];
  27. static DEFINE_MUTEX(nlm_file_mutex);
  28. #ifdef NFSD_DEBUG
  29. static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
  30. {
  31. u32 *fhp = (u32*)f->data;
  32. /* print the first 32 bytes of the fh */
  33. dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
  34. msg, fhp[0], fhp[1], fhp[2], fhp[3],
  35. fhp[4], fhp[5], fhp[6], fhp[7]);
  36. }
  37. static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
  38. {
  39. struct inode *inode = file->f_file->f_path.dentry->d_inode;
  40. dprintk("lockd: %s %s/%ld\n",
  41. msg, inode->i_sb->s_id, inode->i_ino);
  42. }
  43. #else
  44. static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
  45. {
  46. return;
  47. }
  48. static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
  49. {
  50. return;
  51. }
  52. #endif
  53. static inline unsigned int file_hash(struct nfs_fh *f)
  54. {
  55. unsigned int tmp=0;
  56. int i;
  57. for (i=0; i<NFS2_FHSIZE;i++)
  58. tmp += f->data[i];
  59. return tmp & (FILE_NRHASH - 1);
  60. }
  61. /*
  62. * Lookup file info. If it doesn't exist, create a file info struct
  63. * and open a (VFS) file for the given inode.
  64. *
  65. * FIXME:
  66. * Note that we open the file O_RDONLY even when creating write locks.
  67. * This is not quite right, but for now, we assume the client performs
  68. * the proper R/W checking.
  69. */
  70. __be32
  71. nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
  72. struct nfs_fh *f)
  73. {
  74. struct hlist_node *pos;
  75. struct nlm_file *file;
  76. unsigned int hash;
  77. __be32 nfserr;
  78. nlm_debug_print_fh("nlm_file_lookup", f);
  79. hash = file_hash(f);
  80. /* Lock file table */
  81. mutex_lock(&nlm_file_mutex);
  82. hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
  83. if (!nfs_compare_fh(&file->f_handle, f))
  84. goto found;
  85. nlm_debug_print_fh("creating file for", f);
  86. nfserr = nlm_lck_denied_nolocks;
  87. file = kzalloc(sizeof(*file), GFP_KERNEL);
  88. if (!file)
  89. goto out_unlock;
  90. memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
  91. mutex_init(&file->f_mutex);
  92. INIT_HLIST_NODE(&file->f_list);
  93. INIT_LIST_HEAD(&file->f_blocks);
  94. /* Open the file. Note that this must not sleep for too long, else
  95. * we would lock up lockd:-) So no NFS re-exports, folks.
  96. *
  97. * We have to make sure we have the right credential to open
  98. * the file.
  99. */
  100. if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
  101. dprintk("lockd: open failed (error %d)\n", nfserr);
  102. goto out_free;
  103. }
  104. hlist_add_head(&file->f_list, &nlm_files[hash]);
  105. found:
  106. dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
  107. *result = file;
  108. file->f_count++;
  109. nfserr = 0;
  110. out_unlock:
  111. mutex_unlock(&nlm_file_mutex);
  112. return nfserr;
  113. out_free:
  114. kfree(file);
  115. goto out_unlock;
  116. }
  117. /*
  118. * Delete a file after having released all locks, blocks and shares
  119. */
  120. static inline void
  121. nlm_delete_file(struct nlm_file *file)
  122. {
  123. nlm_debug_print_file("closing file", file);
  124. if (!hlist_unhashed(&file->f_list)) {
  125. hlist_del(&file->f_list);
  126. nlmsvc_ops->fclose(file->f_file);
  127. kfree(file);
  128. } else {
  129. printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
  130. }
  131. }
  132. /*
  133. * Loop over all locks on the given file and perform the specified
  134. * action.
  135. */
  136. static int
  137. nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
  138. nlm_host_match_fn_t match)
  139. {
  140. struct inode *inode = nlmsvc_file_inode(file);
  141. struct file_lock *fl;
  142. struct nlm_host *lockhost;
  143. again:
  144. file->f_locks = 0;
  145. for (fl = inode->i_flock; fl; fl = fl->fl_next) {
  146. if (fl->fl_lmops != &nlmsvc_lock_operations)
  147. continue;
  148. /* update current lock count */
  149. file->f_locks++;
  150. lockhost = (struct nlm_host *) fl->fl_owner;
  151. if (match(lockhost, host)) {
  152. struct file_lock lock = *fl;
  153. lock.fl_type = F_UNLCK;
  154. lock.fl_start = 0;
  155. lock.fl_end = OFFSET_MAX;
  156. if (posix_lock_file(file->f_file, &lock) < 0) {
  157. printk("lockd: unlock failure in %s:%d\n",
  158. __FILE__, __LINE__);
  159. return 1;
  160. }
  161. goto again;
  162. }
  163. }
  164. return 0;
  165. }
  166. /*
  167. * Inspect a single file
  168. */
  169. static inline int
  170. nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
  171. {
  172. nlmsvc_traverse_blocks(host, file, match);
  173. nlmsvc_traverse_shares(host, file, match);
  174. return nlm_traverse_locks(host, file, match);
  175. }
  176. /*
  177. * Quick check whether there are still any locks, blocks or
  178. * shares on a given file.
  179. */
  180. static inline int
  181. nlm_file_inuse(struct nlm_file *file)
  182. {
  183. struct inode *inode = nlmsvc_file_inode(file);
  184. struct file_lock *fl;
  185. if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
  186. return 1;
  187. for (fl = inode->i_flock; fl; fl = fl->fl_next) {
  188. if (fl->fl_lmops == &nlmsvc_lock_operations)
  189. return 1;
  190. }
  191. file->f_locks = 0;
  192. return 0;
  193. }
  194. /*
  195. * Loop over all files in the file table.
  196. */
  197. static int
  198. nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
  199. {
  200. struct hlist_node *pos, *next;
  201. struct nlm_file *file;
  202. int i, ret = 0;
  203. mutex_lock(&nlm_file_mutex);
  204. for (i = 0; i < FILE_NRHASH; i++) {
  205. hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
  206. file->f_count++;
  207. mutex_unlock(&nlm_file_mutex);
  208. /* Traverse locks, blocks and shares of this file
  209. * and update file->f_locks count */
  210. if (nlm_inspect_file(host, file, match))
  211. ret = 1;
  212. mutex_lock(&nlm_file_mutex);
  213. file->f_count--;
  214. /* No more references to this file. Let go of it. */
  215. if (list_empty(&file->f_blocks) && !file->f_locks
  216. && !file->f_shares && !file->f_count) {
  217. hlist_del(&file->f_list);
  218. nlmsvc_ops->fclose(file->f_file);
  219. kfree(file);
  220. }
  221. }
  222. }
  223. mutex_unlock(&nlm_file_mutex);
  224. return ret;
  225. }
  226. /*
  227. * Release file. If there are no more remote locks on this file,
  228. * close it and free the handle.
  229. *
  230. * Note that we can't do proper reference counting without major
  231. * contortions because the code in fs/locks.c creates, deletes and
  232. * splits locks without notification. Our only way is to walk the
  233. * entire lock list each time we remove a lock.
  234. */
  235. void
  236. nlm_release_file(struct nlm_file *file)
  237. {
  238. dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
  239. file, file->f_count);
  240. /* Lock file table */
  241. mutex_lock(&nlm_file_mutex);
  242. /* If there are no more locks etc, delete the file */
  243. if (--file->f_count == 0 && !nlm_file_inuse(file))
  244. nlm_delete_file(file);
  245. mutex_unlock(&nlm_file_mutex);
  246. }
  247. /*
  248. * Helpers function for resource traversal
  249. *
  250. * nlmsvc_mark_host:
  251. * used by the garbage collector; simply sets h_inuse.
  252. * Always returns 0.
  253. *
  254. * nlmsvc_same_host:
  255. * returns 1 iff the two hosts match. Used to release
  256. * all resources bound to a specific host.
  257. *
  258. * nlmsvc_is_client:
  259. * returns 1 iff the host is a client.
  260. * Used by nlmsvc_invalidate_all
  261. */
  262. static int
  263. nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
  264. {
  265. host->h_inuse = 1;
  266. return 0;
  267. }
  268. static int
  269. nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
  270. {
  271. return host == other;
  272. }
  273. static int
  274. nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
  275. {
  276. if (host->h_server) {
  277. /* we are destroying locks even though the client
  278. * hasn't asked us too, so don't unmonitor the
  279. * client
  280. */
  281. if (host->h_nsmhandle)
  282. host->h_nsmhandle->sm_sticky = 1;
  283. return 1;
  284. } else
  285. return 0;
  286. }
  287. /*
  288. * Mark all hosts that still hold resources
  289. */
  290. void
  291. nlmsvc_mark_resources(void)
  292. {
  293. dprintk("lockd: nlmsvc_mark_resources\n");
  294. nlm_traverse_files(NULL, nlmsvc_mark_host);
  295. }
  296. /*
  297. * Release all resources held by the given client
  298. */
  299. void
  300. nlmsvc_free_host_resources(struct nlm_host *host)
  301. {
  302. dprintk("lockd: nlmsvc_free_host_resources\n");
  303. if (nlm_traverse_files(host, nlmsvc_same_host)) {
  304. printk(KERN_WARNING
  305. "lockd: couldn't remove all locks held by %s\n",
  306. host->h_name);
  307. BUG();
  308. }
  309. }
  310. /*
  311. * Remove all locks held for clients
  312. */
  313. void
  314. nlmsvc_invalidate_all(void)
  315. {
  316. /* Release all locks held by NFS clients.
  317. * Previously, the code would call
  318. * nlmsvc_free_host_resources for each client in
  319. * turn, which is about as inefficient as it gets.
  320. * Now we just do it once in nlm_traverse_files.
  321. */
  322. nlm_traverse_files(NULL, nlmsvc_is_client);
  323. }