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 u32
  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         u32             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 #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         nlm_debug_print_file("closing file", file);
 154         if (!hlist_unhashed(&file->f_list)) {
 155                 hlist_del(&file->f_list);
 156                 nlmsvc_ops->fclose(file->f_file);
 157                 kfree(file);
 158         } else {
 159                 printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
 160         }
 161 }
 162
 163 /*
 164  * Loop over all locks on the given file and perform the specified
 165  * action.
 166  */
 167 static int
 168 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 169                         nlm_host_match_fn_t match)
 170 {
 171         struct inode     *inode = nlmsvc_file_inode(file);
 172         struct file_lock *fl;
 173         struct nlm_host  *lockhost;
 174
 175 again:
 176         file->f_locks = 0;
 177         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 178                 if (fl->fl_lmops != &nlmsvc_lock_operations)
 179                         continue;
 180
 181                 /* update current lock count */
 182                 file->f_locks++;
 183
 184                 lockhost = (struct nlm_host *) fl->fl_owner;
 185                 if (match(lockhost, host)) {
 186                         struct file_lock lock = *fl;
 187
 188                         lock.fl_type  = F_UNLCK;
 189                         lock.fl_start = 0;
 190                         lock.fl_end   = OFFSET_MAX;
 191                         if (posix_lock_file(file->f_file, &lock) < 0) {
 192                                 printk("lockd: unlock failure in %s:%d\n",
 193                                                 __FILE__, __LINE__);
 194                                 return 1;
 195                         }
 196                         goto again;
 197                 }
 198         }
 199
 200         return 0;
 201 }
 202
 203 /*
 204  * Inspect a single file
 205  */
 206 static inline int
 207 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
 208 {
 209         nlmsvc_traverse_blocks(host, file, match);
 210         nlmsvc_traverse_shares(host, file, match);
 211         return nlm_traverse_locks(host, file, match);
 212 }
 213
 214 /*
 215  * Quick check whether there are still any locks, blocks or
 216  * shares on a given file.
 217  */
 218 static inline int
 219 nlm_file_inuse(struct nlm_file *file)
 220 {
 221         struct inode     *inode = nlmsvc_file_inode(file);
 222         struct file_lock *fl;
 223
 224         if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
 225                 return 1;
 226
 227         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 228                 if (fl->fl_lmops == &nlmsvc_lock_operations)
 229                         return 1;
 230         }
 231         file->f_locks = 0;
 232         return 0;
 233 }
 234
 235 /*
 236  * Loop over all files in the file table.
 237  */
 238 static int
 239 nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
 240 {
 241         struct hlist_node *pos, *next;
 242         struct nlm_file *file;
 243         int i, ret = 0;
 244
 245         mutex_lock(&nlm_file_mutex);
 246         for (i = 0; i < FILE_NRHASH; i++) {
 247                 hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
 248                         file->f_count++;
 249                         mutex_unlock(&nlm_file_mutex);
 250
 251                         /* Traverse locks, blocks and shares of this file
 252                          * and update file->f_locks count */
 253                         if (nlm_inspect_file(host, file, match))
 254                                 ret = 1;
 255
 256                         mutex_lock(&nlm_file_mutex);
 257                         file->f_count--;
 258                         /* No more references to this file. Let go of it. */
 259                         if (list_empty(&file->f_blocks) && !file->f_locks
 260                          && !file->f_shares && !file->f_count) {
 261                                 hlist_del(&file->f_list);
 262                                 nlmsvc_ops->fclose(file->f_file);
 263                                 kfree(file);
 264                         }
 265                 }
 266         }
 267         mutex_unlock(&nlm_file_mutex);
 268         return ret;
 269 }
 270
 271 /*
 272  * Release file. If there are no more remote locks on this file,
 273  * close it and free the handle.
 274  *
 275  * Note that we can't do proper reference counting without major
 276  * contortions because the code in fs/locks.c creates, deletes and
 277  * splits locks without notification. Our only way is to walk the
 278  * entire lock list each time we remove a lock.
 279  */
 280 void
 281 nlm_release_file(struct nlm_file *file)
 282 {
 283         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 284                                 file, file->f_count);
 285
 286         /* Lock file table */
 287         mutex_lock(&nlm_file_mutex);
 288
 289         /* If there are no more locks etc, delete the file */
 290         if (--file->f_count == 0 && !nlm_file_inuse(file))
 291                 nlm_delete_file(file);
 292
 293         mutex_unlock(&nlm_file_mutex);
 294 }
 295
 296 /*
 297  * Helpers function for resource traversal
 298  *
 299  * nlmsvc_mark_host:
 300  *      used by the garbage collector; simply sets h_inuse.
 301  *      Always returns 0.
 302  *
 303  * nlmsvc_same_host:
 304  *      returns 1 iff the two hosts match. Used to release
 305  *      all resources bound to a specific host.
 306  *
 307  * nlmsvc_is_client:
 308  *      returns 1 iff the host is a client.
 309  *      Used by nlmsvc_invalidate_all
 310  */
 311 static int
 312 nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
 313 {
 314         host->h_inuse = 1;
 315         return 0;
 316 }
 317
 318 static int
 319 nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
 320 {
 321         return host == other;
 322 }
 323
 324 static int
 325 nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
 326 {
 327         return host->h_server;
 328 }
 329
 330 /*
 331  * Mark all hosts that still hold resources
 332  */
 333 void
 334 nlmsvc_mark_resources(void)
 335 {
 336         dprintk("lockd: nlmsvc_mark_resources\n");
 337         nlm_traverse_files(NULL, nlmsvc_mark_host);
 338 }
 339
 340 /*
 341  * Release all resources held by the given client
 342  */
 343 void
 344 nlmsvc_free_host_resources(struct nlm_host *host)
 345 {
 346         dprintk("lockd: nlmsvc_free_host_resources\n");
 347
 348         if (nlm_traverse_files(host, nlmsvc_same_host)) {
 349                 printk(KERN_WARNING
 350                         "lockd: couldn't remove all locks held by %s\n",
 351                         host->h_name);
 352                 BUG();
 353         }
 354 }
 355
 356 /*
 357  * Remove all locks held for clients
 358  */
 359 void
 360 nlmsvc_invalidate_all(void)
 361 {
 362         /* Release all locks held by NFS clients.
 363          * Previously, the code would call
 364          * nlmsvc_free_host_resources for each client in
 365          * turn, which is about as inefficient as it gets.
 366          * Now we just do it once in nlm_traverse_files.
 367          */
 368         nlm_traverse_files(NULL, nlmsvc_is_client);
 369 }