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