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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* NFS filesystem cache interface definitions
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _NFS_FSCACHE_H
#define _NFS_FSCACHE_H
#include <linux/swap.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/fscache.h>
#include <linux/iversion.h>
#ifdef CONFIG_NFS_FSCACHE
/*
* Definition of the auxiliary data attached to NFS inode storage objects
* within the cache.
*
* The contents of this struct are recorded in the on-disk local cache in the
* auxiliary data attached to the data storage object backing an inode. This
* permits coherency to be managed when a new inode binds to an already extant
* cache object.
*/
struct nfs_fscache_inode_auxdata {
s64 mtime_sec;
s64 mtime_nsec;
s64 ctime_sec;
s64 ctime_nsec;
u64 change_attr;
};
/*
* fscache.c
*/
extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
extern void nfs_fscache_release_super_cookie(struct super_block *);
extern void nfs_fscache_init_inode(struct inode *);
extern void nfs_fscache_clear_inode(struct inode *);
extern void nfs_fscache_open_file(struct inode *, struct file *);
extern void nfs_fscache_release_file(struct inode *, struct file *);
extern int __nfs_fscache_read_page(struct inode *, struct page *);
extern void __nfs_fscache_write_page(struct inode *, struct page *);
static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
{
if (PageFsCache(page)) {
if (current_is_kswapd() || !(gfp & __GFP_FS))
return false;
wait_on_page_fscache(page);
fscache_note_page_release(nfs_i_fscache(page->mapping->host));
nfs_inc_fscache_stats(page->mapping->host,
NFSIOS_FSCACHE_PAGES_UNCACHED);
}
return true;
}
/*
* Retrieve a page from an inode data storage object.
*/
static inline int nfs_fscache_read_page(struct inode *inode, struct page *page)
{
if (nfs_i_fscache(inode))
return __nfs_fscache_read_page(inode, page);
return -ENOBUFS;
}
/*
* Store a page newly fetched from the server in an inode data storage object
* in the cache.
*/
static inline void nfs_fscache_write_page(struct inode *inode,
struct page *page)
{
if (nfs_i_fscache(inode))
__nfs_fscache_write_page(inode, page);
}
static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
struct inode *inode)
{
memset(auxdata, 0, sizeof(*auxdata));
auxdata->mtime_sec = inode->i_mtime.tv_sec;
auxdata->mtime_nsec = inode->i_mtime.tv_nsec;
auxdata->ctime_sec = inode->i_ctime.tv_sec;
auxdata->ctime_nsec = inode->i_ctime.tv_nsec;
if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4)
auxdata->change_attr = inode_peek_iversion_raw(inode);
}
/*
* Invalidate the contents of fscache for this inode. This will not sleep.
*/
static inline void nfs_fscache_invalidate(struct inode *inode, int flags)
{
struct nfs_fscache_inode_auxdata auxdata;
struct nfs_inode *nfsi = NFS_I(inode);
if (nfsi->fscache) {
nfs_fscache_update_auxdata(&auxdata, inode);
fscache_invalidate(nfsi->fscache, &auxdata,
i_size_read(inode), flags);
}
}
/*
* indicate the client caching state as readable text
*/
static inline const char *nfs_server_fscache_state(struct nfs_server *server)
{
if (server->fscache)
return "yes";
return "no ";
}
#else /* CONFIG_NFS_FSCACHE */
static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
static inline void nfs_fscache_init_inode(struct inode *inode) {}
static inline void nfs_fscache_clear_inode(struct inode *inode) {}
static inline void nfs_fscache_open_file(struct inode *inode,
struct file *filp) {}
static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {}
static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
{
return 1; /* True: may release page */
}
static inline int nfs_fscache_read_page(struct inode *inode, struct page *page)
{
return -ENOBUFS;
}
static inline void nfs_fscache_write_page(struct inode *inode, struct page *page) {}
static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {}
static inline const char *nfs_server_fscache_state(struct nfs_server *server)
{
return "no ";
}
#endif /* CONFIG_NFS_FSCACHE */
#endif /* _NFS_FSCACHE_H */
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