linux/fs/lockd/svcsubs.c
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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
   9#include <linux/types.h>
  10#include <linux/string.h>
  11#include <linux/time.h>
  12#include <linux/in.h>
  13#include <linux/slab.h>
  14#include <linux/mutex.h>
  15#include <linux/sunrpc/svc.h>
  16#include <linux/sunrpc/clnt.h>
  17#include <linux/nfsd/nfsfh.h>
  18#include <linux/nfsd/export.h>
  19#include <linux/lockd/lockd.h>
  20#include <linux/lockd/share.h>
  21#include <linux/module.h>
  22#include <linux/mount.h>
  23
  24#define NLMDBG_FACILITY         NLMDBG_SVCSUBS
  25
  26
  27/*
  28 * Global file hash table
  29 */
  30#define FILE_HASH_BITS          7
  31#define FILE_NRHASH             (1<<FILE_HASH_BITS)
  32static struct hlist_head        nlm_files[FILE_NRHASH];
  33static DEFINE_MUTEX(nlm_file_mutex);
  34
  35#ifdef NFSD_DEBUG
  36static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
  37{
  38        u32 *fhp = (u32*)f->data;
  39
  40        /* print the first 32 bytes of the fh */
  41        dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
  42                msg, fhp[0], fhp[1], fhp[2], fhp[3],
  43                fhp[4], fhp[5], fhp[6], fhp[7]);
  44}
  45
  46static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
  47{
  48        struct inode *inode = file->f_file->f_path.dentry->d_inode;
  49
  50        dprintk("lockd: %s %s/%ld\n",
  51                msg, inode->i_sb->s_id, inode->i_ino);
  52}
  53#else
  54static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
  55{
  56        return;
  57}
  58
  59static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
  60{
  61        return;
  62}
  63#endif
  64
  65static inline unsigned int file_hash(struct nfs_fh *f)
  66{
  67        unsigned int tmp=0;
  68        int i;
  69        for (i=0; i<NFS2_FHSIZE;i++)
  70                tmp += f->data[i];
  71        return tmp & (FILE_NRHASH - 1);
  72}
  73
  74/*
  75 * Lookup file info. If it doesn't exist, create a file info struct
  76 * and open a (VFS) file for the given inode.
  77 *
  78 * FIXME:
  79 * Note that we open the file O_RDONLY even when creating write locks.
  80 * This is not quite right, but for now, we assume the client performs
  81 * the proper R/W checking.
  82 */
  83__be32
  84nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
  85                                        struct nfs_fh *f)
  86{
  87        struct hlist_node *pos;
  88        struct nlm_file *file;
  89        unsigned int    hash;
  90        __be32          nfserr;
  91
  92        nlm_debug_print_fh("nlm_lookup_file", f);
  93
  94        hash = file_hash(f);
  95
  96        /* Lock file table */
  97        mutex_lock(&nlm_file_mutex);
  98
  99        hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
 100                if (!nfs_compare_fh(&file->f_handle, f))
 101                        goto found;
 102
 103        nlm_debug_print_fh("creating file for", f);
 104
 105        nfserr = nlm_lck_denied_nolocks;
 106        file = kzalloc(sizeof(*file), GFP_KERNEL);
 107        if (!file)
 108                goto out_unlock;
 109
 110        memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
 111        mutex_init(&file->f_mutex);
 112        INIT_HLIST_NODE(&file->f_list);
 113        INIT_LIST_HEAD(&file->f_blocks);
 114
 115        /* Open the file. Note that this must not sleep for too long, else
 116         * we would lock up lockd:-) So no NFS re-exports, folks.
 117         *
 118         * We have to make sure we have the right credential to open
 119         * the file.
 120         */
 121        if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
 122                dprintk("lockd: open failed (error %d)\n", nfserr);
 123                goto out_free;
 124        }
 125
 126        hlist_add_head(&file->f_list, &nlm_files[hash]);
 127
 128found:
 129        dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
 130        *result = file;
 131        file->f_count++;
 132        nfserr = 0;
 133
 134out_unlock:
 135        mutex_unlock(&nlm_file_mutex);
 136        return nfserr;
 137
 138out_free:
 139        kfree(file);
 140        goto out_unlock;
 141}
 142
 143/*
 144 * Delete a file after having released all locks, blocks and shares
 145 */
 146static inline void
 147nlm_delete_file(struct nlm_file *file)
 148{
 149        nlm_debug_print_file("closing file", file);
 150        if (!hlist_unhashed(&file->f_list)) {
 151                hlist_del(&file->f_list);
 152                nlmsvc_ops->fclose(file->f_file);
 153                kfree(file);
 154        } else {
 155                printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
 156        }
 157}
 158
 159/*
 160 * Loop over all locks on the given file and perform the specified
 161 * action.
 162 */
 163static int
 164nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
 165                        nlm_host_match_fn_t match)
 166{
 167        struct inode     *inode = nlmsvc_file_inode(file);
 168        struct file_lock *fl;
 169        struct nlm_host  *lockhost;
 170
 171again:
 172        file->f_locks = 0;
 173        lock_flocks(); /* protects i_flock list */
 174        for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 175                if (fl->fl_lmops != &nlmsvc_lock_operations)
 176                        continue;
 177
 178                /* update current lock count */
 179                file->f_locks++;
 180
 181                lockhost = (struct nlm_host *) fl->fl_owner;
 182                if (match(lockhost, host)) {
 183                        struct file_lock lock = *fl;
 184
 185                        unlock_flocks();
 186                        lock.fl_type  = F_UNLCK;
 187                        lock.fl_start = 0;
 188                        lock.fl_end   = OFFSET_MAX;
 189                        if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
 190                                printk("lockd: unlock failure in %s:%d\n",
 191                                                __FILE__, __LINE__);
 192                                return 1;
 193                        }
 194                        goto again;
 195                }
 196        }
 197        unlock_flocks();
 198
 199        return 0;
 200}
 201
 202static int
 203nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
 204{
 205        return 1;
 206}
 207
 208/*
 209 * Inspect a single file
 210 */
 211static inline int
 212nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
 213{
 214        nlmsvc_traverse_blocks(host, file, match);
 215        nlmsvc_traverse_shares(host, file, match);
 216        return nlm_traverse_locks(host, file, match);
 217}
 218
 219/*
 220 * Quick check whether there are still any locks, blocks or
 221 * shares on a given file.
 222 */
 223static inline int
 224nlm_file_inuse(struct nlm_file *file)
 225{
 226        struct inode     *inode = nlmsvc_file_inode(file);
 227        struct file_lock *fl;
 228
 229        if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
 230                return 1;
 231
 232        lock_flocks();
 233        for (fl = inode->i_flock; fl; fl = fl->fl_next) {
 234                if (fl->fl_lmops == &nlmsvc_lock_operations) {
 235                        unlock_flocks();
 236                        return 1;
 237                }
 238        }
 239        unlock_flocks();
 240        file->f_locks = 0;
 241        return 0;
 242}
 243
 244/*
 245 * Loop over all files in the file table.
 246 */
 247static int
 248nlm_traverse_files(void *data, nlm_host_match_fn_t match,
 249                int (*is_failover_file)(void *data, struct nlm_file *file))
 250{
 251        struct hlist_node *pos, *next;
 252        struct nlm_file *file;
 253        int i, ret = 0;
 254
 255        mutex_lock(&nlm_file_mutex);
 256        for (i = 0; i < FILE_NRHASH; i++) {
 257                hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
 258                        if (is_failover_file && !is_failover_file(data, file))
 259                                continue;
 260                        file->f_count++;
 261                        mutex_unlock(&nlm_file_mutex);
 262
 263                        /* Traverse locks, blocks and shares of this file
 264                         * and update file->f_locks count */
 265                        if (nlm_inspect_file(data, file, match))
 266                                ret = 1;
 267
 268                        mutex_lock(&nlm_file_mutex);
 269                        file->f_count--;
 270                        /* No more references to this file. Let go of it. */
 271                        if (list_empty(&file->f_blocks) && !file->f_locks
 272                         && !file->f_shares && !file->f_count) {
 273                                hlist_del(&file->f_list);
 274                                nlmsvc_ops->fclose(file->f_file);
 275                                kfree(file);
 276                        }
 277                }
 278        }
 279        mutex_unlock(&nlm_file_mutex);
 280        return ret;
 281}
 282
 283/*
 284 * Release file. If there are no more remote locks on this file,
 285 * close it and free the handle.
 286 *
 287 * Note that we can't do proper reference counting without major
 288 * contortions because the code in fs/locks.c creates, deletes and
 289 * splits locks without notification. Our only way is to walk the
 290 * entire lock list each time we remove a lock.
 291 */
 292void
 293nlm_release_file(struct nlm_file *file)
 294{
 295        dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 296                                file, file->f_count);
 297
 298        /* Lock file table */
 299        mutex_lock(&nlm_file_mutex);
 300
 301        /* If there are no more locks etc, delete the file */
 302        if (--file->f_count == 0 && !nlm_file_inuse(file))
 303                nlm_delete_file(file);
 304
 305        mutex_unlock(&nlm_file_mutex);
 306}
 307
 308/*
 309 * Helpers function for resource traversal
 310 *
 311 * nlmsvc_mark_host:
 312 *      used by the garbage collector; simply sets h_inuse only for those
 313 *      hosts, which passed network check.
 314 *      Always returns 0.
 315 *
 316 * nlmsvc_same_host:
 317 *      returns 1 iff the two hosts match. Used to release
 318 *      all resources bound to a specific host.
 319 *
 320 * nlmsvc_is_client:
 321 *      returns 1 iff the host is a client.
 322 *      Used by nlmsvc_invalidate_all
 323 */
 324
 325static int
 326nlmsvc_mark_host(void *data, struct nlm_host *hint)
 327{
 328        struct nlm_host *host = data;
 329
 330        if ((hint->net == NULL) ||
 331            (host->net == hint->net))
 332                host->h_inuse = 1;
 333        return 0;
 334}
 335
 336static int
 337nlmsvc_same_host(void *data, struct nlm_host *other)
 338{
 339        struct nlm_host *host = data;
 340
 341        return host == other;
 342}
 343
 344static int
 345nlmsvc_is_client(void *data, struct nlm_host *dummy)
 346{
 347        struct nlm_host *host = data;
 348
 349        if (host->h_server) {
 350                /* we are destroying locks even though the client
 351                 * hasn't asked us too, so don't unmonitor the
 352                 * client
 353                 */
 354                if (host->h_nsmhandle)
 355                        host->h_nsmhandle->sm_sticky = 1;
 356                return 1;
 357        } else
 358                return 0;
 359}
 360
 361/*
 362 * Mark all hosts that still hold resources
 363 */
 364void
 365nlmsvc_mark_resources(struct net *net)
 366{
 367        struct nlm_host hint;
 368
 369        dprintk("lockd: nlmsvc_mark_resources for net %p\n", net);
 370        hint.net = net;
 371        nlm_traverse_files(&hint, nlmsvc_mark_host, NULL);
 372}
 373
 374/*
 375 * Release all resources held by the given client
 376 */
 377void
 378nlmsvc_free_host_resources(struct nlm_host *host)
 379{
 380        dprintk("lockd: nlmsvc_free_host_resources\n");
 381
 382        if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
 383                printk(KERN_WARNING
 384                        "lockd: couldn't remove all locks held by %s\n",
 385                        host->h_name);
 386                BUG();
 387        }
 388}
 389
 390/**
 391 * nlmsvc_invalidate_all - remove all locks held for clients
 392 *
 393 * Release all locks held by NFS clients.
 394 *
 395 */
 396void
 397nlmsvc_invalidate_all(void)
 398{
 399        /*
 400         * Previously, the code would call
 401         * nlmsvc_free_host_resources for each client in
 402         * turn, which is about as inefficient as it gets.
 403         * Now we just do it once in nlm_traverse_files.
 404         */
 405        nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
 406}
 407
 408static int
 409nlmsvc_match_sb(void *datap, struct nlm_file *file)
 410{
 411        struct super_block *sb = datap;
 412
 413        return sb == file->f_file->f_path.dentry->d_sb;
 414}
 415
 416/**
 417 * nlmsvc_unlock_all_by_sb - release locks held on this file system
 418 * @sb: super block
 419 *
 420 * Release all locks held by clients accessing this file system.
 421 */
 422int
 423nlmsvc_unlock_all_by_sb(struct super_block *sb)
 424{
 425        int ret;
 426
 427        ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
 428        return ret ? -EIO : 0;
 429}
 430EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
 431
 432static int
 433nlmsvc_match_ip(void *datap, struct nlm_host *host)
 434{
 435        return rpc_cmp_addr(nlm_srcaddr(host), datap);
 436}
 437
 438/**
 439 * nlmsvc_unlock_all_by_ip - release local locks by IP address
 440 * @server_addr: server's IP address as seen by clients
 441 *
 442 * Release all locks held by clients accessing this host
 443 * via the passed in IP address.
 444 */
 445int
 446nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
 447{
 448        int ret;
 449
 450        ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
 451        return ret ? -EIO : 0;
 452}
 453EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
 454
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