LXR linux/fs/fscache/netfs.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* FS-Cache netfs (client) registration
   3 *
   4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#define FSCACHE_DEBUG_LEVEL COOKIE
   9#include <linux/module.h>
  10#include <linux/slab.h>
  11#include "internal.h"
  12
  13/*
  14 * register a network filesystem for caching
  15 */
  16int __fscache_register_netfs(struct fscache_netfs *netfs)
  17{
  18        struct fscache_cookie *candidate, *cookie;
  19
  20        _enter("{%s}", netfs->name);
  21
  22        /* allocate a cookie for the primary index */
  23        candidate = fscache_alloc_cookie(&fscache_fsdef_index,
  24                                         &fscache_fsdef_netfs_def,
  25                                         netfs->name, strlen(netfs->name),
  26                                         &netfs->version, sizeof(netfs->version),
  27                                         netfs, 0);
  28        if (!candidate) {
  29                _leave(" = -ENOMEM");
  30                return -ENOMEM;
  31        }
  32
  33        candidate->flags = 1 << FSCACHE_COOKIE_ENABLED;
  34
  35        /* check the netfs type is not already present */
  36        cookie = fscache_hash_cookie(candidate);
  37        if (!cookie)
  38                goto already_registered;
  39        if (cookie != candidate) {
  40                trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
  41                fscache_free_cookie(candidate);
  42        }
  43
  44        fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs);
  45        atomic_inc(&cookie->parent->n_children);
  46
  47        netfs->primary_index = cookie;
  48
  49        pr_notice("Netfs '%s' registered for caching\n", netfs->name);
  50        trace_fscache_netfs(netfs);
  51        _leave(" = 0");
  52        return 0;
  53
  54already_registered:
  55        fscache_cookie_put(candidate, fscache_cookie_put_dup_netfs);
  56        _leave(" = -EEXIST");
  57        return -EEXIST;
  58}
  59EXPORT_SYMBOL(__fscache_register_netfs);
  60
  61/*
  62 * unregister a network filesystem from the cache
  63 * - all cookies must have been released first
  64 */
  65void __fscache_unregister_netfs(struct fscache_netfs *netfs)
  66{
  67        _enter("{%s.%u}", netfs->name, netfs->version);
  68
  69        fscache_relinquish_cookie(netfs->primary_index, NULL, false);
  70        pr_notice("Netfs '%s' unregistered from caching\n", netfs->name);
  71
  72        _leave("");
  73}
  74EXPORT_SYMBOL(__fscache_unregister_netfs);
  75