linux/fs/nfs/fscache.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* NFS filesystem cache interface
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 */

#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/seq_file.h>
#include <linux/slab.h>
#include <linux/iversion.h>
#include <linux/xarray.h>
#include <linux/fscache.h>
#include <linux/netfs.h>

#include "internal.h"
#include "iostat.h"
#include "fscache.h"
#include "nfstrace.h"

#define NFS_MAX_KEY_LEN …

static bool nfs_append_int(char *key, int *_len, unsigned long long x)
{ … }

/*
 * Get the per-client index cookie for an NFS client if the appropriate mount
 * flag was set
 * - We always try and get an index cookie for the client, but get filehandle
 *   cookies on a per-superblock basis, depending on the mount flags
 */
static bool nfs_fscache_get_client_key(struct nfs_client *clp,
				       char *key, int *_len)
{ … }

/*
 * Get the cache cookie for an NFS superblock.
 *
 * The default uniquifier is just an empty string, but it may be overridden
 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
 * superblock across an automount point of some nature.
 */
int nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
{ … }

/*
 * release a per-superblock cookie
 */
void nfs_fscache_release_super_cookie(struct super_block *sb)
{ … }

/*
 * Initialise the per-inode cache cookie pointer for an NFS inode.
 */
void nfs_fscache_init_inode(struct inode *inode)
{ … }

/*
 * Release a per-inode cookie.
 */
void nfs_fscache_clear_inode(struct inode *inode)
{ … }

/*
 * Enable or disable caching for a file that is being opened as appropriate.
 * The cookie is allocated when the inode is initialised, but is not enabled at
 * that time.  Enablement is deferred to file-open time to avoid stat() and
 * access() thrashing the cache.
 *
 * For now, with NFS, only regular files that are open read-only will be able
 * to use the cache.
 *
 * We enable the cache for an inode if we open it read-only and it isn't
 * currently open for writing.  We disable the cache if the inode is open
 * write-only.
 *
 * The caller uses the file struct to pin i_writecount on the inode before
 * calling us when a file is opened for writing, so we can make use of that.
 *
 * Note that this may be invoked multiple times in parallel by parallel
 * nfs_open() functions.
 */
void nfs_fscache_open_file(struct inode *inode, struct file *filp)
{ … }
EXPORT_SYMBOL_GPL(…);

void nfs_fscache_release_file(struct inode *inode, struct file *filp)
{ … }

int nfs_netfs_read_folio(struct file *file, struct folio *folio)
{ … }

int nfs_netfs_readahead(struct readahead_control *ractl)
{ … }

static atomic_t nfs_netfs_debug_id;
static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file *file)
{ … }

static void nfs_netfs_free_request(struct netfs_io_request *rreq)
{ … }

static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest *sreq)
{ … }

static bool nfs_netfs_clamp_length(struct netfs_io_subrequest *sreq)
{ … }

static void nfs_netfs_issue_read(struct netfs_io_subrequest *sreq)
{ … }

void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr)
{ … }

int nfs_netfs_folio_unlock(struct folio *folio)
{ … }

void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
{ … }

const struct netfs_request_ops nfs_netfs_ops = …;