// SPDX-License-Identifier: GPL-2.0-or-later

  /* NFS FS-Cache index structure definition
   *
   * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)

   */
  
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/nfs_fs.h>
  #include <linux/nfs_fs_sb.h>
  #include <linux/in6.h>

  #include <linux/iversion.h>

  
  #include "internal.h"
  #include "fscache.h"
  
  #define NFSDBG_FACILITY		NFSDBG_FSCACHE
  
  /*
   * Define the NFS filesystem for FS-Cache.  Upon registration FS-Cache sticks
   * the cookie for the top-level index object for NFS into here.  The top-level
   * index can than have other cache objects inserted into it.
   */
  struct fscache_netfs nfs_fscache_netfs = {
  	.name		= "nfs",
  	.version	= 0,
  };
  
  /*
   * Register NFS for caching
   */
  int nfs_fscache_register(void)
  {
  	return fscache_register_netfs(&nfs_fscache_netfs);
  }
  
  /*
   * Unregister NFS for caching
   */
  void nfs_fscache_unregister(void)
  {
  	fscache_unregister_netfs(&nfs_fscache_netfs);
  }

  
  /*

   * Define the server object for FS-Cache.  This is used to describe a server
   * object to fscache_acquire_cookie().  It is keyed by the NFS protocol and
   * server address parameters.
   */
  const struct fscache_cookie_def nfs_fscache_server_index_def = {
  	.name		= "NFS.server",
  	.type 		= FSCACHE_COOKIE_TYPE_INDEX,

  };

  
  /*

   * Define the superblock object for FS-Cache.  This is used to describe a
   * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
   * parameters that might cause a separate superblock.
   */
  const struct fscache_cookie_def nfs_fscache_super_index_def = {
  	.name		= "NFS.super",
  	.type 		= FSCACHE_COOKIE_TYPE_INDEX,

  };

  
  /*

   * Consult the netfs about the state of an object
   * - This function can be absent if the index carries no state data
   * - The netfs data from the cookie being used as the target is
   *   presented, as is the auxiliary data
   */
  static
  enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
  						  const void *data,

  						  uint16_t datalen,
  						  loff_t object_size)

  {
  	struct nfs_fscache_inode_auxdata auxdata;
  	struct nfs_inode *nfsi = cookie_netfs_data;
  
  	if (datalen != sizeof(auxdata))
  		return FSCACHE_CHECKAUX_OBSOLETE;
  
  	memset(&auxdata, 0, sizeof(auxdata));

  	auxdata.mtime_sec  = nfsi->vfs_inode.i_mtime.tv_sec;
  	auxdata.mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec;
  	auxdata.ctime_sec  = nfsi->vfs_inode.i_ctime.tv_sec;
  	auxdata.ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec;

  
  	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)

  		auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);

  
  	if (memcmp(data, &auxdata, datalen) != 0)
  		return FSCACHE_CHECKAUX_OBSOLETE;
  
  	return FSCACHE_CHECKAUX_OKAY;
  }
  
  /*

   * Get an extra reference on a read context.
   * - This function can be absent if the completion function doesn't require a
   *   context.
   * - The read context is passed back to NFS in the event that a data read on the
   *   cache fails with EIO - in which case the server must be contacted to
   *   retrieve the data, which requires the read context for security.
   */
  static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
  {
  	get_nfs_open_context(context);
  }
  
  /*
   * Release an extra reference on a read context.
   * - This function can be absent if the completion function doesn't require a
   *   context.
   */
  static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
  {
  	if (context)
  		put_nfs_open_context(context);
  }
  
  /*

   * Define the inode object for FS-Cache.  This is used to describe an inode
   * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
   * an inode.
   *
   * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
   * held in the cache auxiliary data for the data storage object with those in
   * the inode struct in memory.
   */
  const struct fscache_cookie_def nfs_fscache_inode_object_def = {
  	.name		= "NFS.fh",
  	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,

  	.check_aux	= nfs_fscache_inode_check_aux,

  	.get_context	= nfs_fh_get_context,
  	.put_context	= nfs_fh_put_context,

  };