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  */
  27 struct fscache_netfs nfs_fscache_netfs = {
  28         .name           = "nfs",
  29         .version        = 0,
  30 };
  31
  32 /*
  33  * Register NFS for caching
  34  */
  35 int nfs_fscache_register(void)
  36 {
  37         return fscache_register_netfs(&nfs_fscache_netfs);
  38 }
  39
  40 /*
  41  * Unregister NFS for caching
  42  */
  43 void 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  */
  53 const 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  */
  63 const 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  */
  74 static
  75 enum 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 = timespec64_to_timespec(nfsi->vfs_inode.i_mtime);
  88         auxdata.ctime = timespec64_to_timespec(nfsi->vfs_inode.i_ctime);
  89
  90         if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
  91                 auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
  92
  93         if (memcmp(data, &auxdata, datalen) != 0)
  94                 return FSCACHE_CHECKAUX_OBSOLETE;
  95
  96         return FSCACHE_CHECKAUX_OKAY;
  97 }
  98
  99 /*
 100  * Get an extra reference on a read context.
 101  * - This function can be absent if the completion function doesn't require a
 102  *   context.
 103  * - The read context is passed back to NFS in the event that a data read on the
 104  *   cache fails with EIO - in which case the server must be contacted to
 105  *   retrieve the data, which requires the read context for security.
 106  */
 107 static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
 108 {
 109         get_nfs_open_context(context);
 110 }
 111
 112 /*
 113  * Release an extra reference on a read context.
 114  * - This function can be absent if the completion function doesn't require a
 115  *   context.
 116  */
 117 static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
 118 {
 119         if (context)
 120                 put_nfs_open_context(context);
 121 }
 122
 123 /*
 124  * Define the inode object for FS-Cache.  This is used to describe an inode
 125  * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
 126  * an inode.
 127  *
 128  * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
 129  * held in the cache auxiliary data for the data storage object with those in
 130  * the inode struct in memory.
 131  */
 132 const struct fscache_cookie_def nfs_fscache_inode_object_def = {
 133         .name           = "NFS.fh",
 134         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 135         .check_aux      = nfs_fscache_inode_check_aux,
 136         .get_context    = nfs_fh_get_context,
 137         .put_context    = nfs_fh_put_context,
 138 };