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/mutex.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          7
  29 #define FILE_NRHASH             (1<<FILE_HASH_BITS)
  30 static struct hlist_head        nlm_files[FILE_NRHASH];
  31 static DEFINE_MUTEX(nlm_file_mutex);
  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 __be32
  82 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
  83                                         struct nfs_fh *f)
  84 {
  85         struct hlist_node *pos;
  86         struct nlm_file *file;
  87         unsigned int    hash;
  88         __be32          nfserr;
  89
  90         nlm_debug_print_fh("nlm_file_lookup", f);
  91
  92         hash = file_hash(f);
  93
  94         /* Lock file table */
  95         mutex_lock(&nlm_file_mutex);
  96
  97         hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
  98                 if (!nfs_compare_fh(&file->f_handle, f))
  99                         goto found;
 100
 101         nlm_debug_print_fh("creating file for", f);
 102
 103         nfserr = nlm_lck_denied_nolocks;
 104         file = kzalloc(sizeof(*file), GFP_KERNEL);
 105         if (!file)
 106                 goto out_unlock;
 107
 108         memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
 109         mutex_init(&file->f_mutex);
 110         INIT_HLIST_NODE(&file->f_list);
 111         INIT_LIST_HEAD(&file->f_blocks);
 112
 113         /* Open the file. Note that this must not sleep for too long, else
 114          * we would lock up lockd:-) So no NFS re-exports, folks.
 115          *
 116          * We have to make sure we have the right credential to open
 117          * the file.
 118          */
 119         if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
 120                 dprintk("lockd: open failed (error %d)\n", nfserr);
 121                 goto out_free;
 122         }
 123
 124         hlist_add_head(&file->f_list, &nlm_files[hash]);
 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         mutex_unlock(&nlm_file_mutex);
 134         return nfserr;
 135
 136 out_free:
 137         kfree(file);
 138         goto out_unlock;
 139 }
 140
 141 /*
 142  * Delete a file after having released all locks, blocks and shares
 143  */
 144 static inline void
 145 nlm_delete_file(struct nlm_file *file)
 146 {
 147         nlm_debug_print_file("closing file", file);
 148         if (!hlist_unhashed(&file->f_list)) {
 149                 hlist_del(&file->f_list);
 150                 nlmsvc_ops->fclose(file->f_file);
 151                 kfree(file);
 152         } else {
 153                 printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
 154         }
 155 }
 156
 157 /*
 158  * Loop over all locks on the given file and perform the specified
 159  * action.
 160  */
 161 static int
 162 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 163                         nlm_host_match_fn_t match)
 164 {
 165         struct inode     *inode = nlmsvc_file_inode(file);
 166         struct file_lock *fl;
 167         struct nlm_host  *lockhost;
 168
 169 again:
 170         file->f_locks = 0;
 171         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 172                 if (fl->fl_lmops != &nlmsvc_lock_operations)
 173                         continue;
 174
 175                 /* update current lock count */
 176                 file->f_locks++;
 177
 178                 lockhost = (struct nlm_host *) fl->fl_owner;
 179                 if (match(lockhost, host)) {
 180                         struct file_lock lock = *fl;
 181
 182                         lock.fl_type  = F_UNLCK;
 183                         lock.fl_start = 0;
 184                         lock.fl_end   = OFFSET_MAX;
 185                         if (posix_lock_file(file->f_file, &lock) < 0) {
 186                                 printk("lockd: unlock failure in %s:%d\n",
 187                                                 __FILE__, __LINE__);
 188                                 return 1;
 189                         }
 190                         goto again;
 191                 }
 192         }
 193
 194         return 0;
 195 }
 196
 197 /*
 198  * Inspect a single file
 199  */
 200 static inline int
 201 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
 202 {
 203         nlmsvc_traverse_blocks(host, file, match);
 204         nlmsvc_traverse_shares(host, file, match);
 205         return nlm_traverse_locks(host, file, match);
 206 }
 207
 208 /*
 209  * Quick check whether there are still any locks, blocks or
 210  * shares on a given file.
 211  */
 212 static inline int
 213 nlm_file_inuse(struct nlm_file *file)
 214 {
 215         struct inode     *inode = nlmsvc_file_inode(file);
 216         struct file_lock *fl;
 217
 218         if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
 219                 return 1;
 220
 221         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 222                 if (fl->fl_lmops == &nlmsvc_lock_operations)
 223                         return 1;
 224         }
 225         file->f_locks = 0;
 226         return 0;
 227 }
 228
 229 /*
 230  * Loop over all files in the file table.
 231  */
 232 static int
 233 nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
 234 {
 235         struct hlist_node *pos, *next;
 236         struct nlm_file *file;
 237         int i, ret = 0;
 238
 239         mutex_lock(&nlm_file_mutex);
 240         for (i = 0; i < FILE_NRHASH; i++) {
 241                 hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
 242                         file->f_count++;
 243                         mutex_unlock(&nlm_file_mutex);
 244
 245                         /* Traverse locks, blocks and shares of this file
 246                          * and update file->f_locks count */
 247                         if (nlm_inspect_file(host, file, match))
 248                                 ret = 1;
 249
 250                         mutex_lock(&nlm_file_mutex);
 251                         file->f_count--;
 252                         /* No more references to this file. Let go of it. */
 253                         if (list_empty(&file->f_blocks) && !file->f_locks
 254                          && !file->f_shares && !file->f_count) {
 255                                 hlist_del(&file->f_list);
 256                                 nlmsvc_ops->fclose(file->f_file);
 257                                 kfree(file);
 258                         }
 259                 }
 260         }
 261         mutex_unlock(&nlm_file_mutex);
 262         return ret;
 263 }
 264
 265 /*
 266  * Release file. If there are no more remote locks on this file,
 267  * close it and free the handle.
 268  *
 269  * Note that we can't do proper reference counting without major
 270  * contortions because the code in fs/locks.c creates, deletes and
 271  * splits locks without notification. Our only way is to walk the
 272  * entire lock list each time we remove a lock.
 273  */
 274 void
 275 nlm_release_file(struct nlm_file *file)
 276 {
 277         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 278                                 file, file->f_count);
 279
 280         /* Lock file table */
 281         mutex_lock(&nlm_file_mutex);
 282
 283         /* If there are no more locks etc, delete the file */
 284         if (--file->f_count == 0 && !nlm_file_inuse(file))
 285                 nlm_delete_file(file);
 286
 287         mutex_unlock(&nlm_file_mutex);
 288 }
 289
 290 /*
 291  * Helpers function for resource traversal
 292  *
 293  * nlmsvc_mark_host:
 294  *      used by the garbage collector; simply sets h_inuse.
 295  *      Always returns 0.
 296  *
 297  * nlmsvc_same_host:
 298  *      returns 1 iff the two hosts match. Used to release
 299  *      all resources bound to a specific host.
 300  *
 301  * nlmsvc_is_client:
 302  *      returns 1 iff the host is a client.
 303  *      Used by nlmsvc_invalidate_all
 304  */
 305 static int
 306 nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
 307 {
 308         host->h_inuse = 1;
 309         return 0;
 310 }
 311
 312 static int
 313 nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
 314 {
 315         return host == other;
 316 }
 317
 318 static int
 319 nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
 320 {
 321         if (host->h_server) {
 322                 /* we are destroying locks even though the client
 323                  * hasn't asked us too, so don't unmonitor the
 324                  * client
 325                  */
 326                 if (host->h_nsmhandle)
 327                         host->h_nsmhandle->sm_sticky = 1;
 328                 return 1;
 329         } else
 330                 return 0;
 331 }
 332
 333 /*
 334  * Mark all hosts that still hold resources
 335  */
 336 void
 337 nlmsvc_mark_resources(void)
 338 {
 339         dprintk("lockd: nlmsvc_mark_resources\n");
 340         nlm_traverse_files(NULL, nlmsvc_mark_host);
 341 }
 342
 343 /*
 344  * Release all resources held by the given client
 345  */
 346 void
 347 nlmsvc_free_host_resources(struct nlm_host *host)
 348 {
 349         dprintk("lockd: nlmsvc_free_host_resources\n");
 350
 351         if (nlm_traverse_files(host, nlmsvc_same_host)) {
 352                 printk(KERN_WARNING
 353                         "lockd: couldn't remove all locks held by %s\n",
 354                         host->h_name);
 355                 BUG();
 356         }
 357 }
 358
 359 /*
 360  * Remove all locks held for clients
 361  */
 362 void
 363 nlmsvc_invalidate_all(void)
 364 {
 365         /* Release all locks held by NFS clients.
 366          * Previously, the code would call
 367          * nlmsvc_free_host_resources for each client in
 368          * turn, which is about as inefficient as it gets.
 369          * Now we just do it once in nlm_traverse_files.
 370          */
 371         nlm_traverse_files(NULL, nlmsvc_is_client);
 372 }