fs/afs/cache.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* AFS caching stuff
   3  *
   4  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #include <linux/sched.h>
   9 #include "internal.h"
  10
  11 static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
  12                                                        const void *buffer,
  13                                                        uint16_t buflen,
  14                                                        loff_t object_size);
  15
  16 struct fscache_netfs afs_cache_netfs = {
  17         .name                   = "afs",
  18         .version                = 2,
  19 };
  20
  21 struct fscache_cookie_def afs_cell_cache_index_def = {
  22         .name           = "AFS.cell",
  23         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  24 };
  25
  26 struct fscache_cookie_def afs_volume_cache_index_def = {
  27         .name           = "AFS.volume",
  28         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  29 };
  30
  31 struct fscache_cookie_def afs_vnode_cache_index_def = {
  32         .name           = "AFS.vnode",
  33         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
  34         .check_aux      = afs_vnode_cache_check_aux,
  35 };
  36
  37 /*
  38  * check that the auxiliary data indicates that the entry is still valid
  39  */
  40 static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
  41                                                        const void *buffer,
  42                                                        uint16_t buflen,
  43                                                        loff_t object_size)
  44 {
  45         struct afs_vnode *vnode = cookie_netfs_data;
  46         struct afs_vnode_cache_aux aux;
  47
  48         _enter("{%llx,%x,%llx},%p,%u",
  49                vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
  50                buffer, buflen);
  51
  52         memcpy(&aux, buffer, sizeof(aux));
  53
  54         /* check the size of the data is what we're expecting */
  55         if (buflen != sizeof(aux)) {
  56                 _leave(" = OBSOLETE [len %hx != %zx]", buflen, sizeof(aux));
  57                 return FSCACHE_CHECKAUX_OBSOLETE;
  58         }
  59
  60         if (vnode->status.data_version != aux.data_version) {
  61                 _leave(" = OBSOLETE [vers %llx != %llx]",
  62                        aux.data_version, vnode->status.data_version);
  63                 return FSCACHE_CHECKAUX_OBSOLETE;
  64         }
  65
  66         _leave(" = SUCCESS");
  67         return FSCACHE_CHECKAUX_OKAY;
  68 }