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![David Howells](/assets/img/avatar_default.png)
Add read context retention so that FS-Cache can call back into NFS when a read operation on the cache fails EIO rather than reading data. This permits NFS to then fetch the data from the server instead using the appropriate security context. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
337 lines
9.3 KiB
C
337 lines
9.3 KiB
C
/* NFS FS-Cache index structure definition
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*
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* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_fs_sb.h>
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#include <linux/in6.h>
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#include "internal.h"
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#include "fscache.h"
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#define NFSDBG_FACILITY NFSDBG_FSCACHE
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/*
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* Define the NFS filesystem for FS-Cache. Upon registration FS-Cache sticks
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* the cookie for the top-level index object for NFS into here. The top-level
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* index can than have other cache objects inserted into it.
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*/
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struct fscache_netfs nfs_fscache_netfs = {
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.name = "nfs",
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.version = 0,
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};
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/*
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* Register NFS for caching
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*/
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int nfs_fscache_register(void)
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{
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return fscache_register_netfs(&nfs_fscache_netfs);
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}
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/*
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* Unregister NFS for caching
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*/
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void nfs_fscache_unregister(void)
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{
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fscache_unregister_netfs(&nfs_fscache_netfs);
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}
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/*
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* Layout of the key for an NFS server cache object.
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*/
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struct nfs_server_key {
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uint16_t nfsversion; /* NFS protocol version */
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uint16_t family; /* address family */
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uint16_t port; /* IP port */
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union {
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struct in_addr ipv4_addr; /* IPv4 address */
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struct in6_addr ipv6_addr; /* IPv6 address */
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} addr[0];
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};
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/*
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* Generate a key to describe a server in the main NFS index
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* - We return the length of the key, or 0 if we can't generate one
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*/
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static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
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void *buffer, uint16_t bufmax)
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{
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const struct nfs_client *clp = cookie_netfs_data;
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const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
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const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
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struct nfs_server_key *key = buffer;
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uint16_t len = sizeof(struct nfs_server_key);
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key->nfsversion = clp->rpc_ops->version;
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key->family = clp->cl_addr.ss_family;
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memset(key, 0, len);
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switch (clp->cl_addr.ss_family) {
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case AF_INET:
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key->port = sin->sin_port;
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key->addr[0].ipv4_addr = sin->sin_addr;
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len += sizeof(key->addr[0].ipv4_addr);
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break;
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case AF_INET6:
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key->port = sin6->sin6_port;
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key->addr[0].ipv6_addr = sin6->sin6_addr;
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len += sizeof(key->addr[0].ipv6_addr);
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break;
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default:
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printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
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clp->cl_addr.ss_family);
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len = 0;
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break;
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}
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return len;
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}
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/*
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* Define the server object for FS-Cache. This is used to describe a server
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* object to fscache_acquire_cookie(). It is keyed by the NFS protocol and
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* server address parameters.
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*/
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const struct fscache_cookie_def nfs_fscache_server_index_def = {
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.name = "NFS.server",
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.type = FSCACHE_COOKIE_TYPE_INDEX,
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.get_key = nfs_server_get_key,
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};
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/*
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* Generate a key to describe a superblock key in the main NFS index
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*/
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static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
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void *buffer, uint16_t bufmax)
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{
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const struct nfs_fscache_key *key;
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const struct nfs_server *nfss = cookie_netfs_data;
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uint16_t len;
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key = nfss->fscache_key;
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len = sizeof(key->key) + key->key.uniq_len;
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if (len > bufmax) {
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len = 0;
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} else {
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memcpy(buffer, &key->key, sizeof(key->key));
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memcpy(buffer + sizeof(key->key),
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key->key.uniquifier, key->key.uniq_len);
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}
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return len;
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}
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/*
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* Define the superblock object for FS-Cache. This is used to describe a
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* superblock object to fscache_acquire_cookie(). It is keyed by all the NFS
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* parameters that might cause a separate superblock.
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*/
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const struct fscache_cookie_def nfs_fscache_super_index_def = {
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.name = "NFS.super",
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.type = FSCACHE_COOKIE_TYPE_INDEX,
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.get_key = nfs_super_get_key,
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};
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/*
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* Definition of the auxiliary data attached to NFS inode storage objects
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* within the cache.
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*
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* The contents of this struct are recorded in the on-disk local cache in the
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* auxiliary data attached to the data storage object backing an inode. This
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* permits coherency to be managed when a new inode binds to an already extant
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* cache object.
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*/
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struct nfs_fscache_inode_auxdata {
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struct timespec mtime;
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struct timespec ctime;
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loff_t size;
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u64 change_attr;
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};
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/*
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* Generate a key to describe an NFS inode in an NFS server's index
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*/
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static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
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void *buffer, uint16_t bufmax)
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{
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const struct nfs_inode *nfsi = cookie_netfs_data;
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uint16_t nsize;
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/* use the inode's NFS filehandle as the key */
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nsize = nfsi->fh.size;
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memcpy(buffer, nfsi->fh.data, nsize);
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return nsize;
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}
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/*
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* Get certain file attributes from the netfs data
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* - This function can be absent for an index
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* - Not permitted to return an error
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* - The netfs data from the cookie being used as the source is presented
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*/
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static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
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uint64_t *size)
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{
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const struct nfs_inode *nfsi = cookie_netfs_data;
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*size = nfsi->vfs_inode.i_size;
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}
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/*
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* Get the auxiliary data from netfs data
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* - This function can be absent if the index carries no state data
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* - Should store the auxiliary data in the buffer
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* - Should return the amount of amount stored
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* - Not permitted to return an error
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* - The netfs data from the cookie being used as the source is presented
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*/
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static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
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void *buffer, uint16_t bufmax)
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{
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struct nfs_fscache_inode_auxdata auxdata;
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const struct nfs_inode *nfsi = cookie_netfs_data;
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memset(&auxdata, 0, sizeof(auxdata));
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auxdata.size = nfsi->vfs_inode.i_size;
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auxdata.mtime = nfsi->vfs_inode.i_mtime;
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auxdata.ctime = nfsi->vfs_inode.i_ctime;
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if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
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auxdata.change_attr = nfsi->change_attr;
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if (bufmax > sizeof(auxdata))
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bufmax = sizeof(auxdata);
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memcpy(buffer, &auxdata, bufmax);
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return bufmax;
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}
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/*
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* Consult the netfs about the state of an object
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* - This function can be absent if the index carries no state data
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* - The netfs data from the cookie being used as the target is
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* presented, as is the auxiliary data
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*/
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static
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enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
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const void *data,
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uint16_t datalen)
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{
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struct nfs_fscache_inode_auxdata auxdata;
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struct nfs_inode *nfsi = cookie_netfs_data;
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if (datalen != sizeof(auxdata))
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return FSCACHE_CHECKAUX_OBSOLETE;
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memset(&auxdata, 0, sizeof(auxdata));
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auxdata.size = nfsi->vfs_inode.i_size;
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auxdata.mtime = nfsi->vfs_inode.i_mtime;
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auxdata.ctime = nfsi->vfs_inode.i_ctime;
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if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
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auxdata.change_attr = nfsi->change_attr;
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if (memcmp(data, &auxdata, datalen) != 0)
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return FSCACHE_CHECKAUX_OBSOLETE;
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return FSCACHE_CHECKAUX_OKAY;
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}
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/*
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* Indication from FS-Cache that the cookie is no longer cached
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* - This function is called when the backing store currently caching a cookie
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* is removed
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* - The netfs should use this to clean up any markers indicating cached pages
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* - This is mandatory for any object that may have data
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*/
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static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
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{
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struct nfs_inode *nfsi = cookie_netfs_data;
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struct pagevec pvec;
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pgoff_t first;
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int loop, nr_pages;
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pagevec_init(&pvec, 0);
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first = 0;
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dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
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for (;;) {
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/* grab a bunch of pages to unmark */
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nr_pages = pagevec_lookup(&pvec,
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nfsi->vfs_inode.i_mapping,
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first,
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PAGEVEC_SIZE - pagevec_count(&pvec));
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if (!nr_pages)
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break;
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for (loop = 0; loop < nr_pages; loop++)
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ClearPageFsCache(pvec.pages[loop]);
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first = pvec.pages[nr_pages - 1]->index + 1;
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pvec.nr = nr_pages;
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pagevec_release(&pvec);
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cond_resched();
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}
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}
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/*
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* Get an extra reference on a read context.
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* - This function can be absent if the completion function doesn't require a
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* context.
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* - The read context is passed back to NFS in the event that a data read on the
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* cache fails with EIO - in which case the server must be contacted to
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* retrieve the data, which requires the read context for security.
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*/
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static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
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{
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get_nfs_open_context(context);
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}
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/*
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* Release an extra reference on a read context.
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* - This function can be absent if the completion function doesn't require a
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* context.
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*/
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static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
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{
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if (context)
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put_nfs_open_context(context);
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}
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/*
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* Define the inode object for FS-Cache. This is used to describe an inode
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* object to fscache_acquire_cookie(). It is keyed by the NFS file handle for
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* an inode.
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*
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* Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
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* held in the cache auxiliary data for the data storage object with those in
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* the inode struct in memory.
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*/
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const struct fscache_cookie_def nfs_fscache_inode_object_def = {
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.name = "NFS.fh",
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.type = FSCACHE_COOKIE_TYPE_DATAFILE,
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.get_key = nfs_fscache_inode_get_key,
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.get_attr = nfs_fscache_inode_get_attr,
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.get_aux = nfs_fscache_inode_get_aux,
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.check_aux = nfs_fscache_inode_check_aux,
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.now_uncached = nfs_fscache_inode_now_uncached,
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.get_context = nfs_fh_get_context,
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.put_context = nfs_fh_put_context,
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};
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