linux/fs/lockd/svcsubs.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * linux/fs/lockd/svcsubs.c
   4 *
   5 * Various support routines for the NLM server.
   6 *
   7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   8 */
   9
  10#include <linux/types.h>
  11#include <linux/string.h>
  12#include <linux/time.h>
  13#include <linux/in.h>
  14#include <linux/slab.h>
  15#include <linux/mutex.h>
  16#include <linux/sunrpc/svc.h>
  17#include <linux/sunrpc/addr.h>
  18#include <linux/lockd/lockd.h>
  19#include <linux/lockd/share.h>
  20#include <linux/module.h>
  21#include <linux/mount.h>
  22#include <uapi/linux/nfs2.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 CONFIG_SUNRPC_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 = locks_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 file_lock_context *flctx = inode->i_flctx;
 169        struct nlm_host  *lockhost;
 170
 171        if (!flctx || list_empty_careful(&flctx->flc_posix))
 172                return 0;
 173again:
 174        file->f_locks = 0;
 175        spin_lock(&flctx->flc_lock);
 176        list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
 177                if (fl->fl_lmops != &nlmsvc_lock_operations)
 178                        continue;
 179
 180                /* update current lock count */
 181                file->f_locks++;
 182
 183                lockhost = (struct nlm_host *) fl->fl_owner;
 184                if (match(lockhost, host)) {
 185                        struct file_lock lock = *fl;
 186
 187                        spin_unlock(&flctx->flc_lock);
 188                        lock.fl_type  = F_UNLCK;
 189                        lock.fl_start = 0;
 190                        lock.fl_end   = OFFSET_MAX;
 191                        if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
 192                                printk("lockd: unlock failure in %s:%d\n",
 193                                                __FILE__, __LINE__);
 194                                return 1;
 195                        }
 196                        goto again;
 197                }
 198        }
 199        spin_unlock(&flctx->flc_lock);
 200
 201        return 0;
 202}
 203
 204static int
 205nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
 206{
 207        return 1;
 208}
 209
 210/*
 211 * Inspect a single file
 212 */
 213static inline int
 214nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
 215{
 216        nlmsvc_traverse_blocks(host, file, match);
 217        nlmsvc_traverse_shares(host, file, match);
 218        return nlm_traverse_locks(host, file, match);
 219}
 220
 221/*
 222 * Quick check whether there are still any locks, blocks or
 223 * shares on a given file.
 224 */
 225static inline int
 226nlm_file_inuse(struct nlm_file *file)
 227{
 228        struct inode     *inode = nlmsvc_file_inode(file);
 229        struct file_lock *fl;
 230        struct file_lock_context *flctx = inode->i_flctx;
 231
 232        if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
 233                return 1;
 234
 235        if (flctx && !list_empty_careful(&flctx->flc_posix)) {
 236                spin_lock(&flctx->flc_lock);
 237                list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
 238                        if (fl->fl_lmops == &nlmsvc_lock_operations) {
 239                                spin_unlock(&flctx->flc_lock);
 240                                return 1;
 241                        }
 242                }
 243                spin_unlock(&flctx->flc_lock);
 244        }
 245        file->f_locks = 0;
 246        return 0;
 247}
 248
 249/*
 250 * Loop over all files in the file table.
 251 */
 252static int
 253nlm_traverse_files(void *data, nlm_host_match_fn_t match,
 254                int (*is_failover_file)(void *data, struct nlm_file *file))
 255{
 256        struct hlist_node *next;
 257        struct nlm_file *file;
 258        int i, ret = 0;
 259
 260        mutex_lock(&nlm_file_mutex);
 261        for (i = 0; i < FILE_NRHASH; i++) {
 262                hlist_for_each_entry_safe(file, next, &nlm_files[i], f_list) {
 263                        if (is_failover_file && !is_failover_file(data, file))
 264                                continue;
 265                        file->f_count++;
 266                        mutex_unlock(&nlm_file_mutex);
 267
 268                        /* Traverse locks, blocks and shares of this file
 269                         * and update file->f_locks count */
 270                        if (nlm_inspect_file(data, file, match))
 271                                ret = 1;
 272
 273                        mutex_lock(&nlm_file_mutex);
 274                        file->f_count--;
 275                        /* No more references to this file. Let go of it. */
 276                        if (list_empty(&file->f_blocks) && !file->f_locks
 277                         && !file->f_shares && !file->f_count) {
 278                                hlist_del(&file->f_list);
 279                                nlmsvc_ops->fclose(file->f_file);
 280                                kfree(file);
 281                        }
 282                }
 283        }
 284        mutex_unlock(&nlm_file_mutex);
 285        return ret;
 286}
 287
 288/*
 289 * Release file. If there are no more remote locks on this file,
 290 * close it and free the handle.
 291 *
 292 * Note that we can't do proper reference counting without major
 293 * contortions because the code in fs/locks.c creates, deletes and
 294 * splits locks without notification. Our only way is to walk the
 295 * entire lock list each time we remove a lock.
 296 */
 297void
 298nlm_release_file(struct nlm_file *file)
 299{
 300        dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
 301                                file, file->f_count);
 302
 303        /* Lock file table */
 304        mutex_lock(&nlm_file_mutex);
 305
 306        /* If there are no more locks etc, delete the file */
 307        if (--file->f_count == 0 && !nlm_file_inuse(file))
 308                nlm_delete_file(file);
 309
 310        mutex_unlock(&nlm_file_mutex);
 311}
 312
 313/*
 314 * Helpers function for resource traversal
 315 *
 316 * nlmsvc_mark_host:
 317 *      used by the garbage collector; simply sets h_inuse only for those
 318 *      hosts, which passed network check.
 319 *      Always returns 0.
 320 *
 321 * nlmsvc_same_host:
 322 *      returns 1 iff the two hosts match. Used to release
 323 *      all resources bound to a specific host.
 324 *
 325 * nlmsvc_is_client:
 326 *      returns 1 iff the host is a client.
 327 *      Used by nlmsvc_invalidate_all
 328 */
 329
 330static int
 331nlmsvc_mark_host(void *data, struct nlm_host *hint)
 332{
 333        struct nlm_host *host = data;
 334
 335        if ((hint->net == NULL) ||
 336            (host->net == hint->net))
 337                host->h_inuse = 1;
 338        return 0;
 339}
 340
 341static int
 342nlmsvc_same_host(void *data, struct nlm_host *other)
 343{
 344        struct nlm_host *host = data;
 345
 346        return host == other;
 347}
 348
 349static int
 350nlmsvc_is_client(void *data, struct nlm_host *dummy)
 351{
 352        struct nlm_host *host = data;
 353
 354        if (host->h_server) {
 355                /* we are destroying locks even though the client
 356                 * hasn't asked us too, so don't unmonitor the
 357                 * client
 358                 */
 359                if (host->h_nsmhandle)
 360                        host->h_nsmhandle->sm_sticky = 1;
 361                return 1;
 362        } else
 363                return 0;
 364}
 365
 366/*
 367 * Mark all hosts that still hold resources
 368 */
 369void
 370nlmsvc_mark_resources(struct net *net)
 371{
 372        struct nlm_host hint;
 373
 374        dprintk("lockd: %s for net %x\n", __func__, net ? net->ns.inum : 0);
 375        hint.net = net;
 376        nlm_traverse_files(&hint, nlmsvc_mark_host, NULL);
 377}
 378
 379/*
 380 * Release all resources held by the given client
 381 */
 382void
 383nlmsvc_free_host_resources(struct nlm_host *host)
 384{
 385        dprintk("lockd: nlmsvc_free_host_resources\n");
 386
 387        if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
 388                printk(KERN_WARNING
 389                        "lockd: couldn't remove all locks held by %s\n",
 390                        host->h_name);
 391                BUG();
 392        }
 393}
 394
 395/**
 396 * nlmsvc_invalidate_all - remove all locks held for clients
 397 *
 398 * Release all locks held by NFS clients.
 399 *
 400 */
 401void
 402nlmsvc_invalidate_all(void)
 403{
 404        /*
 405         * Previously, the code would call
 406         * nlmsvc_free_host_resources for each client in
 407         * turn, which is about as inefficient as it gets.
 408         * Now we just do it once in nlm_traverse_files.
 409         */
 410        nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
 411}
 412
 413static int
 414nlmsvc_match_sb(void *datap, struct nlm_file *file)
 415{
 416        struct super_block *sb = datap;
 417
 418        return sb == locks_inode(file->f_file)->i_sb;
 419}
 420
 421/**
 422 * nlmsvc_unlock_all_by_sb - release locks held on this file system
 423 * @sb: super block
 424 *
 425 * Release all locks held by clients accessing this file system.
 426 */
 427int
 428nlmsvc_unlock_all_by_sb(struct super_block *sb)
 429{
 430        int ret;
 431
 432        ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
 433        return ret ? -EIO : 0;
 434}
 435EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
 436
 437static int
 438nlmsvc_match_ip(void *datap, struct nlm_host *host)
 439{
 440        return rpc_cmp_addr(nlm_srcaddr(host), datap);
 441}
 442
 443/**
 444 * nlmsvc_unlock_all_by_ip - release local locks by IP address
 445 * @server_addr: server's IP address as seen by clients
 446 *
 447 * Release all locks held by clients accessing this host
 448 * via the passed in IP address.
 449 */
 450int
 451nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
 452{
 453        int ret;
 454
 455        ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
 456        return ret ? -EIO : 0;
 457}
 458EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
 459