// 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 1000
static bool nfs_append_int(char *key, int *_len, unsigned long long x)
{
if (*_len > NFS_MAX_KEY_LEN)
return false;
if (x == 0)
key[(*_len)++] = ',';
else
*_len += sprintf(key + *_len, ",%llx", x);
return true;
}
/*
* 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)
{
const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
*_len += snprintf(key + *_len, NFS_MAX_KEY_LEN - *_len,
",%u.%u,%x",
clp->rpc_ops->version,
clp->cl_minorversion,
clp->cl_addr.ss_family);
switch (clp->cl_addr.ss_family) {
case AF_INET:
if (!nfs_append_int(key, _len, sin->sin_port) ||
!nfs_append_int(key, _len, sin->sin_addr.s_addr))
return false;
return true;
case AF_INET6:
if (!nfs_append_int(key, _len, sin6->sin6_port) ||
!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
!nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
return false;
return true;
default:
printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
clp->cl_addr.ss_family);
return false;
}
}
/*
* 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)
{
struct fscache_volume *vcookie;
struct nfs_server *nfss = NFS_SB(sb);
unsigned int len = 3;
char *key;
if (uniq) {
nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
if (!nfss->fscache_uniq)
return -ENOMEM;
}
key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
if (!key)
return -ENOMEM;
memcpy(key, "nfs", 3);
if (!nfs_fscache_get_client_key(nfss->nfs_client, key, &len) ||
!nfs_append_int(key, &len, nfss->fsid.major) ||
!nfs_append_int(key, &len, nfss->fsid.minor) ||
!nfs_append_int(key, &len, sb->s_flags & NFS_SB_MASK) ||
!nfs_append_int(key, &len, nfss->flags) ||
!nfs_append_int(key, &len, nfss->rsize) ||
!nfs_append_int(key, &len, nfss->wsize) ||
!nfs_append_int(key, &len, nfss->acregmin) ||
!nfs_append_int(key, &len, nfss->acregmax) ||
!nfs_append_int(key, &len, nfss->acdirmin) ||
!nfs_append_int(key, &len, nfss->acdirmax) ||
!nfs_append_int(key, &len, nfss->client->cl_auth->au_flavor))
goto out;
if (ulen > 0) {
if (ulen > NFS_MAX_KEY_LEN - len)
goto out;
key[len++] = ',';
memcpy(key + len, uniq, ulen);
len += ulen;
}
key[len] = 0;
/* create a cache index for looking up filehandles */
vcookie = fscache_acquire_volume(key,
NULL, /* preferred_cache */
NULL, 0 /* coherency_data */);
if (IS_ERR(vcookie)) {
if (vcookie != ERR_PTR(-EBUSY)) {
kfree(key);
return PTR_ERR(vcookie);
}
pr_err("NFS: Cache volume key already in use (%s)\n", key);
vcookie = NULL;
}
nfss->fscache = vcookie;
out:
kfree(key);
return 0;
}
/*
* release a per-superblock cookie
*/
void nfs_fscache_release_super_cookie(struct super_block *sb)
{
struct nfs_server *nfss = NFS_SB(sb);
fscache_relinquish_volume(nfss->fscache, NULL, false);
nfss->fscache = NULL;
kfree(nfss->fscache_uniq);
}
/*
* Initialise the per-inode cache cookie pointer for an NFS inode.
*/
void nfs_fscache_init_inode(struct inode *inode)
{
struct nfs_fscache_inode_auxdata auxdata;
struct nfs_server *nfss = NFS_SERVER(inode);
struct nfs_inode *nfsi = NFS_I(inode);
netfs_inode(inode)->cache = NULL;
if (!(nfss->fscache && S_ISREG(inode->i_mode)))
return;
nfs_fscache_update_auxdata(&auxdata, inode);
netfs_inode(inode)->cache = fscache_acquire_cookie(
nfss->fscache,
0,
nfsi->fh.data, /* index_key */
nfsi->fh.size,
&auxdata, /* aux_data */
sizeof(auxdata),
i_size_read(inode));
if (netfs_inode(inode)->cache)
mapping_set_release_always(inode->i_mapping);
}
/*
* Release a per-inode cookie.
*/
void nfs_fscache_clear_inode(struct inode *inode)
{
fscache_relinquish_cookie(netfs_i_cookie(netfs_inode(inode)), false);
netfs_inode(inode)->cache = NULL;
}
/*
* 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)
{
struct nfs_fscache_inode_auxdata auxdata;
struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
bool open_for_write = inode_is_open_for_write(inode);
if (!fscache_cookie_valid(cookie))
return;
fscache_use_cookie(cookie, open_for_write);
if (open_for_write) {
nfs_fscache_update_auxdata(&auxdata, inode);
fscache_invalidate(cookie, &auxdata, i_size_read(inode),
FSCACHE_INVAL_DIO_WRITE);
}
}
EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
void nfs_fscache_release_file(struct inode *inode, struct file *filp)
{
struct nfs_fscache_inode_auxdata auxdata;
struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
loff_t i_size = i_size_read(inode);
nfs_fscache_update_auxdata(&auxdata, inode);
fscache_unuse_cookie(cookie, &auxdata, &i_size);
}
int nfs_netfs_read_folio(struct file *file, struct folio *folio)
{
if (!netfs_inode(folio_inode(folio))->cache)
return -ENOBUFS;
return netfs_read_folio(file, folio);
}
int nfs_netfs_readahead(struct readahead_control *ractl)
{
struct inode *inode = ractl->mapping->host;
if (!netfs_inode(inode)->cache)
return -ENOBUFS;
netfs_readahead(ractl);
return 0;
}
static atomic_t nfs_netfs_debug_id;
static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file *file)
{
rreq->netfs_priv = get_nfs_open_context(nfs_file_open_context(file));
rreq->debug_id = atomic_inc_return(&nfs_netfs_debug_id);
/* [DEPRECATED] Use PG_private_2 to mark folio being written to the cache. */
__set_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags);
rreq->io_streams[0].sreq_max_len = NFS_SB(rreq->inode->i_sb)->rsize;
return 0;
}
static void nfs_netfs_free_request(struct netfs_io_request *rreq)
{
put_nfs_open_context(rreq->netfs_priv);
}
static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest *sreq)
{
struct nfs_netfs_io_data *netfs;
netfs = kzalloc(sizeof(*netfs), GFP_KERNEL_ACCOUNT);
if (!netfs)
return NULL;
netfs->sreq = sreq;
refcount_set(&netfs->refcount, 1);
return netfs;
}
static void nfs_netfs_issue_read(struct netfs_io_subrequest *sreq)
{
struct nfs_netfs_io_data *netfs;
struct nfs_pageio_descriptor pgio;
struct inode *inode = sreq->rreq->inode;
struct nfs_open_context *ctx = sreq->rreq->netfs_priv;
struct page *page;
unsigned long idx;
pgoff_t start, last;
int err;
start = (sreq->start + sreq->transferred) >> PAGE_SHIFT;
last = ((sreq->start + sreq->len - sreq->transferred - 1) >> PAGE_SHIFT);
nfs_pageio_init_read(&pgio, inode, false,
&nfs_async_read_completion_ops);
netfs = nfs_netfs_alloc(sreq);
if (!netfs)
return netfs_read_subreq_terminated(sreq, -ENOMEM, false);
pgio.pg_netfs = netfs; /* used in completion */
xa_for_each_range(&sreq->rreq->mapping->i_pages, idx, page, start, last) {
/* nfs_read_add_folio() may schedule() due to pNFS layout and other RPCs */
err = nfs_read_add_folio(&pgio, ctx, page_folio(page));
if (err < 0) {
netfs->error = err;
goto out;
}
}
out:
nfs_pageio_complete_read(&pgio);
nfs_netfs_put(netfs);
}
void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr)
{
struct nfs_netfs_io_data *netfs = hdr->netfs;
if (!netfs)
return;
nfs_netfs_get(netfs);
}
int nfs_netfs_folio_unlock(struct folio *folio)
{
struct inode *inode = folio->mapping->host;
/*
* If fscache is enabled, netfs will unlock pages.
*/
if (netfs_inode(inode)->cache)
return 0;
return 1;
}
void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
{
struct nfs_netfs_io_data *netfs = hdr->netfs;
struct netfs_io_subrequest *sreq;
if (!netfs)
return;
sreq = netfs->sreq;
if (test_bit(NFS_IOHDR_EOF, &hdr->flags) &&
sreq->rreq->origin != NETFS_DIO_READ)
__set_bit(NETFS_SREQ_CLEAR_TAIL, &sreq->flags);
if (hdr->error)
netfs->error = hdr->error;
else
atomic64_add(hdr->res.count, &netfs->transferred);
nfs_netfs_put(netfs);
hdr->netfs = NULL;
}
const struct netfs_request_ops nfs_netfs_ops = {
.init_request = nfs_netfs_init_request,
.free_request = nfs_netfs_free_request,
.issue_read = nfs_netfs_issue_read,
};
Codebase Browser
linux