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7f8e05f60c
Store pages from an NFS inode into the cache data storage object associated with that inode. 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>
524 lines
14 KiB
C
524 lines
14 KiB
C
/* NFS filesystem cache interface
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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 <linux/seq_file.h>
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#include "internal.h"
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#include "iostat.h"
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#include "fscache.h"
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#define NFSDBG_FACILITY NFSDBG_FSCACHE
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static struct rb_root nfs_fscache_keys = RB_ROOT;
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static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
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/*
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* Get the per-client index cookie for an NFS client if the appropriate mount
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* flag was set
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* - We always try and get an index cookie for the client, but get filehandle
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* cookies on a per-superblock basis, depending on the mount flags
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*/
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void nfs_fscache_get_client_cookie(struct nfs_client *clp)
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{
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/* create a cache index for looking up filehandles */
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clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
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&nfs_fscache_server_index_def,
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clp);
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dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
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clp, clp->fscache);
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}
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/*
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* Dispose of a per-client cookie
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*/
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void nfs_fscache_release_client_cookie(struct nfs_client *clp)
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{
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dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
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clp, clp->fscache);
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fscache_relinquish_cookie(clp->fscache, 0);
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clp->fscache = NULL;
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}
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/*
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* Get the cache cookie for an NFS superblock. We have to handle
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* uniquification here because the cache doesn't do it for us.
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*/
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void nfs_fscache_get_super_cookie(struct super_block *sb,
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struct nfs_parsed_mount_data *data)
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{
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struct nfs_fscache_key *key, *xkey;
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struct nfs_server *nfss = NFS_SB(sb);
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struct rb_node **p, *parent;
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const char *uniq = data->fscache_uniq ?: "";
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int diff, ulen;
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ulen = strlen(uniq);
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key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
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if (!key)
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return;
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key->nfs_client = nfss->nfs_client;
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key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
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key->key.nfs_server.flags = nfss->flags;
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key->key.nfs_server.rsize = nfss->rsize;
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key->key.nfs_server.wsize = nfss->wsize;
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key->key.nfs_server.acregmin = nfss->acregmin;
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key->key.nfs_server.acregmax = nfss->acregmax;
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key->key.nfs_server.acdirmin = nfss->acdirmin;
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key->key.nfs_server.acdirmax = nfss->acdirmax;
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key->key.nfs_server.fsid = nfss->fsid;
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key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
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key->key.uniq_len = ulen;
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memcpy(key->key.uniquifier, uniq, ulen);
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spin_lock(&nfs_fscache_keys_lock);
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p = &nfs_fscache_keys.rb_node;
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parent = NULL;
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while (*p) {
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parent = *p;
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xkey = rb_entry(parent, struct nfs_fscache_key, node);
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if (key->nfs_client < xkey->nfs_client)
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goto go_left;
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if (key->nfs_client > xkey->nfs_client)
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goto go_right;
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diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
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if (diff < 0)
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goto go_left;
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if (diff > 0)
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goto go_right;
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if (key->key.uniq_len == 0)
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goto non_unique;
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diff = memcmp(key->key.uniquifier,
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xkey->key.uniquifier,
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key->key.uniq_len);
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if (diff < 0)
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goto go_left;
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if (diff > 0)
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goto go_right;
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goto non_unique;
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go_left:
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p = &(*p)->rb_left;
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continue;
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go_right:
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p = &(*p)->rb_right;
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}
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rb_link_node(&key->node, parent, p);
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rb_insert_color(&key->node, &nfs_fscache_keys);
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spin_unlock(&nfs_fscache_keys_lock);
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nfss->fscache_key = key;
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/* create a cache index for looking up filehandles */
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nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
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&nfs_fscache_super_index_def,
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nfss);
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dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
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nfss, nfss->fscache);
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return;
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non_unique:
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spin_unlock(&nfs_fscache_keys_lock);
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kfree(key);
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nfss->fscache_key = NULL;
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nfss->fscache = NULL;
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printk(KERN_WARNING "NFS:"
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" Cache request denied due to non-unique superblock keys\n");
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}
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/*
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* release a per-superblock cookie
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*/
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void nfs_fscache_release_super_cookie(struct super_block *sb)
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{
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struct nfs_server *nfss = NFS_SB(sb);
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dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
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nfss, nfss->fscache);
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fscache_relinquish_cookie(nfss->fscache, 0);
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nfss->fscache = NULL;
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if (nfss->fscache_key) {
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spin_lock(&nfs_fscache_keys_lock);
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rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
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spin_unlock(&nfs_fscache_keys_lock);
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kfree(nfss->fscache_key);
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nfss->fscache_key = NULL;
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}
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}
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/*
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* Initialise the per-inode cache cookie pointer for an NFS inode.
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*/
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void nfs_fscache_init_inode_cookie(struct inode *inode)
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{
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NFS_I(inode)->fscache = NULL;
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if (S_ISREG(inode->i_mode))
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set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
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}
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/*
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* Get the per-inode cache cookie for an NFS inode.
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*/
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static void nfs_fscache_enable_inode_cookie(struct inode *inode)
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{
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struct super_block *sb = inode->i_sb;
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struct nfs_inode *nfsi = NFS_I(inode);
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if (nfsi->fscache || !NFS_FSCACHE(inode))
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return;
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if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
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nfsi->fscache = fscache_acquire_cookie(
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NFS_SB(sb)->fscache,
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&nfs_fscache_inode_object_def,
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nfsi);
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dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
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sb, nfsi, nfsi->fscache);
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}
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}
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/*
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* Release a per-inode cookie.
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*/
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void nfs_fscache_release_inode_cookie(struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
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nfsi, nfsi->fscache);
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fscache_relinquish_cookie(nfsi->fscache, 0);
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nfsi->fscache = NULL;
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}
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/*
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* Retire a per-inode cookie, destroying the data attached to it.
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*/
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void nfs_fscache_zap_inode_cookie(struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n",
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nfsi, nfsi->fscache);
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fscache_relinquish_cookie(nfsi->fscache, 1);
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nfsi->fscache = NULL;
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}
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/*
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* Turn off the cache with regard to a per-inode cookie if opened for writing,
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* invalidating all the pages in the page cache relating to the associated
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* inode to clear the per-page caching.
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*/
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static void nfs_fscache_disable_inode_cookie(struct inode *inode)
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{
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clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
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if (NFS_I(inode)->fscache) {
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dfprintk(FSCACHE,
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"NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
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/* Need to invalidate any mapped pages that were read in before
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* turning off the cache.
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*/
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if (inode->i_mapping && inode->i_mapping->nrpages)
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invalidate_inode_pages2(inode->i_mapping);
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nfs_fscache_zap_inode_cookie(inode);
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}
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}
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/*
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* wait_on_bit() sleep function for uninterruptible waiting
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*/
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static int nfs_fscache_wait_bit(void *flags)
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{
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schedule();
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return 0;
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}
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/*
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* Lock against someone else trying to also acquire or relinquish a cookie
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*/
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static inline void nfs_fscache_inode_lock(struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags))
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wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK,
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nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE);
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}
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/*
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* Unlock cookie management lock
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*/
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static inline void nfs_fscache_inode_unlock(struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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smp_mb__before_clear_bit();
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clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags);
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smp_mb__after_clear_bit();
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wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK);
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}
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/*
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* Decide if we should enable or disable local caching for this inode.
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* - For now, with NFS, only regular files that are open read-only will be able
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* to use the cache.
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* - May be invoked multiple times in parallel by parallel nfs_open() functions.
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*/
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void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
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{
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if (NFS_FSCACHE(inode)) {
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nfs_fscache_inode_lock(inode);
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if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
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nfs_fscache_disable_inode_cookie(inode);
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else
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nfs_fscache_enable_inode_cookie(inode);
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nfs_fscache_inode_unlock(inode);
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}
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}
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/*
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* Replace a per-inode cookie due to revalidation detecting a file having
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* changed on the server.
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*/
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void nfs_fscache_reset_inode_cookie(struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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struct nfs_server *nfss = NFS_SERVER(inode);
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struct fscache_cookie *old = nfsi->fscache;
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nfs_fscache_inode_lock(inode);
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if (nfsi->fscache) {
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/* retire the current fscache cache and get a new one */
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fscache_relinquish_cookie(nfsi->fscache, 1);
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nfsi->fscache = fscache_acquire_cookie(
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nfss->nfs_client->fscache,
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&nfs_fscache_inode_object_def,
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nfsi);
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dfprintk(FSCACHE,
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"NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
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nfss, nfsi, old, nfsi->fscache);
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}
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nfs_fscache_inode_unlock(inode);
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}
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/*
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* Release the caching state associated with a page, if the page isn't busy
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* interacting with the cache.
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* - Returns true (can release page) or false (page busy).
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*/
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int nfs_fscache_release_page(struct page *page, gfp_t gfp)
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{
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struct nfs_inode *nfsi = NFS_I(page->mapping->host);
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struct fscache_cookie *cookie = nfsi->fscache;
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BUG_ON(!cookie);
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if (fscache_check_page_write(cookie, page)) {
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if (!(gfp & __GFP_WAIT))
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return 0;
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fscache_wait_on_page_write(cookie, page);
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}
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if (PageFsCache(page)) {
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dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
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cookie, page, nfsi);
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fscache_uncache_page(cookie, page);
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nfs_add_fscache_stats(page->mapping->host,
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NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
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}
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return 1;
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}
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/*
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* Release the caching state associated with a page if undergoing complete page
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* invalidation.
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*/
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void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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struct fscache_cookie *cookie = nfsi->fscache;
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BUG_ON(!cookie);
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dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
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cookie, page, nfsi);
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fscache_wait_on_page_write(cookie, page);
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BUG_ON(!PageLocked(page));
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fscache_uncache_page(cookie, page);
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nfs_add_fscache_stats(page->mapping->host,
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NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
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}
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/*
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* Handle completion of a page being read from the cache.
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* - Called in process (keventd) context.
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*/
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static void nfs_readpage_from_fscache_complete(struct page *page,
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void *context,
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int error)
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{
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dfprintk(FSCACHE,
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"NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
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page, context, error);
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/* if the read completes with an error, we just unlock the page and let
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* the VM reissue the readpage */
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if (!error) {
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SetPageUptodate(page);
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unlock_page(page);
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} else {
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error = nfs_readpage_async(context, page->mapping->host, page);
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if (error)
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unlock_page(page);
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}
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}
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/*
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* Retrieve a page from fscache
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*/
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int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
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struct inode *inode, struct page *page)
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{
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int ret;
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dfprintk(FSCACHE,
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"NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
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NFS_I(inode)->fscache, page, page->index, page->flags, inode);
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ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache,
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page,
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nfs_readpage_from_fscache_complete,
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ctx,
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GFP_KERNEL);
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switch (ret) {
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case 0: /* read BIO submitted (page in fscache) */
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dfprintk(FSCACHE,
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"NFS: readpage_from_fscache: BIO submitted\n");
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nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 1);
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return ret;
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case -ENOBUFS: /* inode not in cache */
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case -ENODATA: /* page not in cache */
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nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
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dfprintk(FSCACHE,
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"NFS: readpage_from_fscache %d\n", ret);
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return 1;
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default:
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dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
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nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 1);
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}
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return ret;
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}
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/*
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* Retrieve a set of pages from fscache
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*/
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int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
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struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages)
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{
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int ret, npages = *nr_pages;
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dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
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NFS_I(inode)->fscache, npages, inode);
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ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache,
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mapping, pages, nr_pages,
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nfs_readpage_from_fscache_complete,
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ctx,
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mapping_gfp_mask(mapping));
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if (*nr_pages < npages)
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nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK,
|
|
npages);
|
|
if (*nr_pages > 0)
|
|
nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL,
|
|
*nr_pages);
|
|
|
|
switch (ret) {
|
|
case 0: /* read submitted to the cache for all pages */
|
|
BUG_ON(!list_empty(pages));
|
|
BUG_ON(*nr_pages != 0);
|
|
dfprintk(FSCACHE,
|
|
"NFS: nfs_getpages_from_fscache: submitted\n");
|
|
|
|
return ret;
|
|
|
|
case -ENOBUFS: /* some pages aren't cached and can't be */
|
|
case -ENODATA: /* some pages aren't cached */
|
|
dfprintk(FSCACHE,
|
|
"NFS: nfs_getpages_from_fscache: no page: %d\n", ret);
|
|
return 1;
|
|
|
|
default:
|
|
dfprintk(FSCACHE,
|
|
"NFS: nfs_getpages_from_fscache: ret %d\n", ret);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Store a newly fetched page in fscache
|
|
* - PG_fscache must be set on the page
|
|
*/
|
|
void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync)
|
|
{
|
|
int ret;
|
|
|
|
dfprintk(FSCACHE,
|
|
"NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n",
|
|
NFS_I(inode)->fscache, page, page->index, page->flags, sync);
|
|
|
|
ret = fscache_write_page(NFS_I(inode)->fscache, page, GFP_KERNEL);
|
|
dfprintk(FSCACHE,
|
|
"NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n",
|
|
page, page->index, page->flags, ret);
|
|
|
|
if (ret != 0) {
|
|
fscache_uncache_page(NFS_I(inode)->fscache, page);
|
|
nfs_add_fscache_stats(inode,
|
|
NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL, 1);
|
|
nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED, 1);
|
|
} else {
|
|
nfs_add_fscache_stats(inode,
|
|
NFSIOS_FSCACHE_PAGES_WRITTEN_OK, 1);
|
|
}
|
|
}
|