LXR linux/fs/nfs/fscache-index.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* NFS FS-Cache index structure definition
   3 *
   4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#include <linux/init.h>
   9#include <linux/kernel.h>
  10#include <linux/sched.h>
  11#include <linux/mm.h>
  12#include <linux/nfs_fs.h>
  13#include <linux/nfs_fs_sb.h>
  14#include <linux/in6.h>
  15#include <linux/iversion.h>
  16
  17#include "internal.h"
  18#include "fscache.h"
  19
  20#define NFSDBG_FACILITY         NFSDBG_FSCACHE
  21
  22/*
  23 * Define the NFS filesystem for FS-Cache.  Upon registration FS-Cache sticks
  24 * the cookie for the top-level index object for NFS into here.  The top-level
  25 * index can than have other cache objects inserted into it.
  26 */
  27struct fscache_netfs nfs_fscache_netfs = {
  28        .name           = "nfs",
  29        .version        = 0,
  30};
  31
  32/*
  33 * Register NFS for caching
  34 */
  35int nfs_fscache_register(void)
  36{
  37        return fscache_register_netfs(&nfs_fscache_netfs);
  38}
  39
  40/*
  41 * Unregister NFS for caching
  42 */
  43void nfs_fscache_unregister(void)
  44{
  45        fscache_unregister_netfs(&nfs_fscache_netfs);
  46}
  47
  48/*
  49 * Define the server object for FS-Cache.  This is used to describe a server
  50 * object to fscache_acquire_cookie().  It is keyed by the NFS protocol and
  51 * server address parameters.
  52 */
  53const struct fscache_cookie_def nfs_fscache_server_index_def = {
  54        .name           = "NFS.server",
  55        .type           = FSCACHE_COOKIE_TYPE_INDEX,
  56};
  57
  58/*
  59 * Define the superblock object for FS-Cache.  This is used to describe a
  60 * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
  61 * parameters that might cause a separate superblock.
  62 */
  63const struct fscache_cookie_def nfs_fscache_super_index_def = {
  64        .name           = "NFS.super",
  65        .type           = FSCACHE_COOKIE_TYPE_INDEX,
  66};
  67
  68/*
  69 * Consult the netfs about the state of an object
  70 * - This function can be absent if the index carries no state data
  71 * - The netfs data from the cookie being used as the target is
  72 *   presented, as is the auxiliary data
  73 */
  74static
  75enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
  76                                                  const void *data,
  77                                                  uint16_t datalen,
  78                                                  loff_t object_size)
  79{
  80        struct nfs_fscache_inode_auxdata auxdata;
  81        struct nfs_inode *nfsi = cookie_netfs_data;
  82
  83        if (datalen != sizeof(auxdata))
  84                return FSCACHE_CHECKAUX_OBSOLETE;
  85
  86        memset(&auxdata, 0, sizeof(auxdata));
  87        auxdata.mtime_sec  = nfsi->vfs_inode.i_mtime.tv_sec;
  88        auxdata.mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec;
  89        auxdata.ctime_sec  = nfsi->vfs_inode.i_ctime.tv_sec;
  90        auxdata.ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec;
  91
  92        if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
  93                auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
  94
  95        if (memcmp(data, &auxdata, datalen) != 0)
  96                return FSCACHE_CHECKAUX_OBSOLETE;
  97
  98        return FSCACHE_CHECKAUX_OKAY;
  99}
 100
 101/*
 102 * Get an extra reference on a read context.
 103 * - This function can be absent if the completion function doesn't require a
 104 *   context.
 105 * - The read context is passed back to NFS in the event that a data read on the
 106 *   cache fails with EIO - in which case the server must be contacted to
 107 *   retrieve the data, which requires the read context for security.
 108 */
 109static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
 110{
 111        get_nfs_open_context(context);
 112}
 113
 114/*
 115 * Release an extra reference on a read context.
 116 * - This function can be absent if the completion function doesn't require a
 117 *   context.
 118 */
 119static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
 120{
 121        if (context)
 122                put_nfs_open_context(context);
 123}
 124
 125/*
 126 * Define the inode object for FS-Cache.  This is used to describe an inode
 127 * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
 128 * an inode.
 129 *
 130 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
 131 * held in the cache auxiliary data for the data storage object with those in
 132 * the inode struct in memory.
 133 */
 134const struct fscache_cookie_def nfs_fscache_inode_object_def = {
 135        .name           = "NFS.fh",
 136        .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 137        .check_aux      = nfs_fscache_inode_check_aux,
 138        .get_context    = nfs_fh_get_context,
 139        .put_context    = nfs_fh_put_context,
 140};
 141