[PATCH 14/22] NFS: Use local caching

From: David Howells
Date: Fri Sep 21 2007 - 10:51:28 EST

The attached patch makes it possible for the NFS filesystem to make use of the
network filesystem local caching service (FS-Cache).

To be able to use this, an updated mount program is required. This can be
obtained from:

http://people.redhat.com/steved/fscache/util-linux/

To mount an NFS filesystem to use caching, add an "fsc" option to the mount:

mount warthog:/ /a -o fsc

Signed-Off-By: David Howells <dhowells@xxxxxxxxxx>
---

fs/nfs/Makefile | 1
fs/nfs/client.c | 5 +
fs/nfs/file.c | 51 ++++++
fs/nfs/fscache-def.c | 288 +++++++++++++++++++++++++++++++++++
fs/nfs/fscache.c | 372 +++++++++++++++++++++++++++++++++++++++++++++
fs/nfs/fscache.h | 144 +++++++++++++++++
fs/nfs/inode.c | 48 +++++-
fs/nfs/read.c | 28 +++
fs/nfs/sysctl.c | 44 +++++
include/linux/nfs_fs.h | 8 +
include/linux/nfs_fs_sb.h | 7 +
11 files changed, 986 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index b55cb23..07c9345 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -16,4 +16,5 @@ nfs-$(CONFIG_NFS_V4) += nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
nfs4namespace.o
nfs-$(CONFIG_NFS_DIRECTIO) += direct.o
nfs-$(CONFIG_SYSCTL) += sysctl.o
+nfs-$(CONFIG_NFS_FSCACHE) += fscache.o fscache-def.o
nfs-objs := $(nfs-y)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index a49f9fe..f1783b2 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -41,6 +41,7 @@
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
+#include "fscache.h"

#define NFSDBG_FACILITY NFSDBG_CLIENT

@@ -137,6 +138,8 @@ static struct nfs_client *nfs_alloc_client(const char *hostname,
clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
#endif

+ nfs_fscache_get_client_cookie(clp);
+
return clp;

error_3:
@@ -168,6 +171,8 @@ static void nfs_free_client(struct nfs_client *clp)

nfs4_shutdown_client(clp);

+ nfs_fscache_release_client_cookie(clp);
+
/* -EIO all pending I/O */
if (!IS_ERR(clp->cl_rpcclient))
rpc_shutdown_client(clp->cl_rpcclient);
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 579cf8a..640179b 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -34,6 +34,8 @@

#include "delegation.h"
#include "iostat.h"
+#include "internal.h"
+#include "fscache.h"

#define NFSDBG_FACILITY NFSDBG_FILE

@@ -54,6 +56,12 @@ static int nfs_check_flags(int flags);
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
+static int nfs_file_page_mkwrite(struct vm_area_struct *vma, struct page *page);
+
+struct vm_operations_struct nfs_fs_vm_operations = {
+ .fault = filemap_fault,
+ .page_mkwrite = nfs_file_page_mkwrite,
+};

const struct file_operations nfs_file_operations = {
.llseek = nfs_file_llseek,
@@ -259,6 +267,9 @@ nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
status = nfs_revalidate_mapping(inode, file->f_mapping);
if (!status)
status = generic_file_mmap(file, vma);
+ if (!status)
+ vma->vm_ops = &nfs_fs_vm_operations;
+
return status;
}

@@ -311,22 +322,48 @@ static int nfs_commit_write(struct file *file, struct page *page, unsigned offse
return status;
}

+/*
+ * Partially or wholly invalidate a page
+ * - Release the private state associated with a page if undergoing complete
+ * page invalidation
+ * - Called if either PG_private or PG_fscache set on the page
+ * - Caller holds page lock
+ */
static void nfs_invalidate_page(struct page *page, unsigned long offset)
{
if (offset != 0)
return;
/* Cancel any unstarted writes on this page */
nfs_wb_page_cancel(page->mapping->host, page);
+
+ nfs_fscache_invalidate_page(page, page->mapping->host);
}

+/*
+ * Release the private state associated with a page
+ * - Called if either PG_private or PG_fscache set on the page
+ * - Caller holds page lock
+ * - Return true (may release) or false (may not)
+ */
static int nfs_release_page(struct page *page, gfp_t gfp)
{
/* If PagePrivate() is set, then the page is not freeable */
- return 0;
+ if (PagePrivate(page))
+ return 0;
+ return nfs_fscache_release_page(page, gfp);
}

+/*
+ * Attempt to clear the private state associated with a page when an error
+ * occurs that requires the cached contents of an inode to be written back or
+ * destroyed
+ * - Called if either PG_private or PG_fscache set on the page
+ * - Caller holds page lock
+ * - Return 0 if successful, -error otherwise
+ */
static int nfs_launder_page(struct page *page)
{
+ wait_on_page_fscache_write(page);
return nfs_wb_page(page->mapping->host, page);
}

@@ -572,3 +609,15 @@ static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
*/
return -EINVAL;
}
+
+/*
+ * Notification that a PTE pointing to an NFS page is about to be made
+ * writable, implying that someone is about to modify the page through a
+ * shared-writable mapping
+ */
+static int nfs_file_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+{
+ /* make sure the cache has finished storing the page */
+ wait_on_page_fscache_write(page);
+ return 0;
+}
diff --git a/fs/nfs/fscache-def.c b/fs/nfs/fscache-def.c
new file mode 100644
index 0000000..4aa2bab
--- /dev/null
+++ b/fs/nfs/fscache-def.c
@@ -0,0 +1,288 @@
+/* NFS FS-Cache index structure definition
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@xxxxxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#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 "internal.h"
+#include "fscache.h"
+
+#define NFSDBG_FACILITY NFSDBG_FSCACHE
+
+/*
+ * Definition of the auxiliary data attached to NFS inode storage objects.
+ * This is used for coherency management.
+ */
+struct nfs_fh_auxdata {
+ struct timespec i_mtime;
+ struct timespec i_ctime;
+ loff_t i_size;
+};
+
+/*
+ * Definition of the key for an NFS server index object. The server's IP
+ * address is stored as an IPv6 address, with IPv4 addresses being wrapped
+ * appropriately.
+ */
+struct nfs_server_key {
+ uint16_t nfsversion;
+ uint16_t port;
+ union {
+ struct {
+ uint8_t ipv6wrapper[12];
+ struct in_addr addr;
+ } ipv4_addr;
+ struct in6_addr ipv6_addr;
+ };
+};
+
+static const struct fscache_netfs_operations nfs_cache_ops = {
+};
+
+struct fscache_netfs nfs_cache_netfs = {
+ .name = "nfs",
+ .version = 0,
+ .ops = &nfs_cache_ops,
+};
+
+static const uint8_t nfs_cache_ipv6_wrapper_for_ipv4[12] = {
+ [0 ... 9] = 0x00,
+ [10 ... 11] = 0xff
+};
+
+/*
+ * Generate a key to describe a server in the main NFS index
+ */
+static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
+ void *buffer, uint16_t bufmax)
+{
+ const struct nfs_client *clp = cookie_netfs_data;
+ struct nfs_server_key *key = buffer;
+ uint16_t len = 0;
+
+ key->nfsversion = clp->cl_nfsversion;
+
+ switch (clp->cl_addr.sin_family) {
+ case AF_INET:
+ key->port = clp->cl_addr.sin_port;
+
+ memcpy(&key->ipv4_addr.ipv6wrapper,
+ &nfs_cache_ipv6_wrapper_for_ipv4,
+ sizeof(key->ipv4_addr.ipv6wrapper));
+ memcpy(&key->ipv4_addr.addr,
+ &clp->cl_addr.sin_addr,
+ sizeof(key->ipv4_addr.addr));
+ len = sizeof(struct nfs_server_key);
+ break;
+
+ case AF_INET6:
+ key->port = clp->cl_addr.sin_port;
+
+ memcpy(&key->ipv6_addr,
+ &clp->cl_addr.sin_addr,
+ sizeof(key->ipv6_addr));
+ len = sizeof(struct nfs_server_key);
+ break;
+
+ default:
+ len = 0;
+ printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
+ clp->cl_addr.sin_family);
+ break;
+ }
+
+ return len;
+}
+
+/*
+ * The root index for the filesystem is defined by nfsd IP address and ports
+ */
+const struct fscache_cookie_def nfs_cache_server_index_def = {
+ .name = "NFS.servers",
+ .type = FSCACHE_COOKIE_TYPE_INDEX,
+ .get_key = nfs_server_get_key,
+};
+
+/*
+ * Generate a key to describe an NFS inode in an NFS server's index
+ */
+static uint16_t nfs_fh_get_key(const void *cookie_netfs_data,
+ void *buffer, uint16_t bufmax)
+{
+ const struct nfs_inode *nfsi = cookie_netfs_data;
+ uint16_t nsize;
+
+ /* use the inode's NFS filehandle as the key */
+ nsize = nfsi->fh.size;
+ memcpy(buffer, nfsi->fh.data, nsize);
+ return nsize;
+}
+
+/*
+ * Get an extra reference on a read context
+ * - This function can be absent if the completion function doesn't require a
+ * context
+ */
+static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
+{
+ get_nfs_open_context(context);
+}
+
+/*
+ * Release an extra reference on a read context
+ * - This function can be absent if the completion function doesn't require a
+ * context
+ */
+static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
+{
+ if (context)
+ put_nfs_open_context(context);
+}
+
+/*
+ * Indication the cookie is no longer uncached
+ * - This function is called when the backing store currently caching a cookie
+ * is removed
+ * - The netfs should use this to clean up any markers indicating cached pages
+ * - This is mandatory for any object that may have data
+ */
+static void nfs_fh_now_uncached(void *cookie_netfs_data)
+{
+ struct nfs_inode *nfsi = cookie_netfs_data;
+ struct pagevec pvec;
+ pgoff_t first;
+ int loop, nr_pages;
+
+ pagevec_init(&pvec, 0);
+ first = 0;
+
+ dprintk("NFS: nfs_fh_now_uncached: nfs_inode 0x%p\n", nfsi);
+
+ for (;;) {
+ /* grab a bunch of pages to clean */
+ nr_pages = pagevec_lookup(&pvec,
+ nfsi->vfs_inode.i_mapping,
+ first,
+ PAGEVEC_SIZE - pagevec_count(&pvec));
+ if (!nr_pages)
+ break;
+
+ for (loop = 0; loop < nr_pages; loop++)
+ ClearPageFsCache(pvec.pages[loop]);
+
+ first = pvec.pages[nr_pages - 1]->index + 1;
+
+ pvec.nr = nr_pages;
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+}
+
+/*
+ * Tet certain file attributes from the netfs data
+ * - This function can be absent for an index
+ * - Not permitted to return an error
+ * - The netfs data from the cookie being used as the source is
+ * presented
+ */
+static void nfs_fh_get_attr(const void *cookie_netfs_data, uint64_t *size)
+{
+ const struct nfs_inode *nfsi = cookie_netfs_data;
+
+ *size = nfsi->vfs_inode.i_size;
+}
+
+/*
+ * Get the auxiliary data from netfs data
+ * - This function can be absent if the index carries no state data
+ * - Should store the auxiliary data in the buffer
+ * - Should return the amount of amount stored
+ * - Not permitted to return an error
+ * - The netfs data from the cookie being used as the source is presented
+ */
+static uint16_t nfs_fh_get_aux(const void *cookie_netfs_data,
+ void *buffer, uint16_t bufmax)
+{
+ struct nfs_fh_auxdata auxdata;
+ const struct nfs_inode *nfsi = cookie_netfs_data;
+
+ auxdata.i_size = nfsi->vfs_inode.i_size;
+ auxdata.i_mtime = nfsi->vfs_inode.i_mtime;
+ auxdata.i_ctime = nfsi->vfs_inode.i_ctime;
+
+ if (bufmax > sizeof(auxdata))
+ bufmax = sizeof(auxdata);
+
+ memcpy(buffer, &auxdata, bufmax);
+ return bufmax;
+}
+
+/*
+ * Consult the netfs about the state of an object
+ * - This function can be absent if the index carries no state data
+ * - The netfs data from the cookie being used as the target is
+ * presented, as is the auxiliary data
+ */
+static fscache_checkaux_t nfs_fh_check_aux(void *cookie_netfs_data,
+ const void *data, uint16_t datalen)
+{
+ struct nfs_fh_auxdata auxdata;
+ struct nfs_inode *nfsi = cookie_netfs_data;
+
+ if (datalen > sizeof(auxdata))
+ return FSCACHE_CHECKAUX_OBSOLETE;
+
+ auxdata.i_size = nfsi->vfs_inode.i_size;
+ auxdata.i_mtime = nfsi->vfs_inode.i_mtime;
+ auxdata.i_ctime = nfsi->vfs_inode.i_ctime;
+
+ if (memcmp(data, &auxdata, datalen) != 0)
+ return FSCACHE_CHECKAUX_OBSOLETE;
+
+ return FSCACHE_CHECKAUX_OKAY;
+}
+
+/*
+ * The primary index for each server is simply made up of a series of NFS file
+ * handles
+ */
+const struct fscache_cookie_def nfs_cache_fh_index_def = {
+ .name = "NFS.fh",
+ .type = FSCACHE_COOKIE_TYPE_DATAFILE,
+ .get_key = nfs_fh_get_key,
+ .get_attr = nfs_fh_get_attr,
+ .get_aux = nfs_fh_get_aux,
+ .check_aux = nfs_fh_check_aux,
+ .get_context = nfs_fh_get_context,
+ .put_context = nfs_fh_put_context,
+ .now_uncached = nfs_fh_now_uncached,
+};
+
+/*
+ * Register NFS for caching
+ */
+int nfs_fscache_register(void)
+{
+ return fscache_register_netfs(&nfs_cache_netfs);
+}
+
+/*
+ * Unregister NFS for caching
+ */
+void nfs_fscache_unregister(void)
+{
+ fscache_unregister_netfs(&nfs_cache_netfs);
+}
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
new file mode 100644
index 0000000..3d122b6
--- /dev/null
+++ b/fs/nfs/fscache.c
@@ -0,0 +1,372 @@
+/* NFS filesystem cache interface
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@xxxxxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#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 "internal.h"
+#include "fscache.h"
+
+#define NFSDBG_FACILITY NFSDBG_FSCACHE
+
+/*
+ * Sysctl variables
+ */
+atomic_t nfs_fscache_to_pages;
+atomic_t nfs_fscache_from_pages;
+atomic_t nfs_fscache_uncache_page;
+int nfs_fscache_from_error;
+int nfs_fscache_to_error;
+
+/*
+ * 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
+ */
+void nfs_fscache_get_client_cookie(struct nfs_client *clp)
+{
+ /* create a cache index for looking up filehandles */
+ clp->fscache = fscache_acquire_cookie(nfs_cache_netfs.primary_index,
+ &nfs_cache_server_index_def,
+ clp);
+ dfprintk(FSCACHE,"NFS: get client cookie (0x%p/0x%p)\n",
+ clp, clp->fscache);
+}
+
+/*
+ * Dispose of a per-client cookie
+ */
+void nfs_fscache_release_client_cookie(struct nfs_client *clp)
+{
+ dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
+ clp, clp->fscache);
+
+ fscache_relinquish_cookie(clp->fscache, 0);
+ clp->fscache = NULL;
+}
+
+/*
+ * Initialise the per-filehandle cookie for an NFS inode
+ */
+void nfs_fscache_init_fh_cookie(struct inode *inode)
+{
+ NFS_I(inode)->fscache = NULL;
+ if (S_ISREG(inode->i_mode))
+ set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+}
+
+/*
+ * Get the per-filehandle cookie for an NFS inode
+ */
+void nfs_fscache_enable_fh_cookie(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ if (nfsi->fscache || !NFS_FSCACHE(inode))
+ return;
+
+ if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
+ nfsi->fscache = fscache_acquire_cookie(
+ NFS_SB(sb)->nfs_client->fscache,
+ &nfs_cache_fh_index_def,
+ nfsi);
+
+ dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
+ sb, nfsi, nfsi->fscache);
+ }
+}
+
+/*
+ * Release a per-filehandle cookie
+ */
+void nfs_fscache_release_fh_cookie(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
+ nfsi, nfsi->fscache);
+
+ fscache_relinquish_cookie(nfsi->fscache, 0);
+ nfsi->fscache = NULL;
+}
+
+/*
+ * Retire a per-filehandle cookie, destroying the data attached to it
+ */
+void nfs_fscache_zap_fh_cookie(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ dfprintk(FSCACHE,"NFS: zapping cookie (0x%p/0x%p)\n",
+ nfsi, nfsi->fscache);
+
+ fscache_relinquish_cookie(nfsi->fscache, 1);
+ nfsi->fscache = NULL;
+}
+
+/*
+ * Turn off the cache with regard to a filehandle cookie if opened for writing,
+ * invalidating all the pages in the page cache relating to the associated
+ * inode to clear the per-page caching
+ */
+void nfs_fscache_disable_fh_cookie(struct inode *inode)
+{
+ clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+
+ if (NFS_I(inode)->fscache) {
+ dfprintk(FSCACHE,
+ "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
+
+ /* Need to invalidate any mapped pages that were read in before
+ * turning off the cache.
+ */
+ if (inode->i_mapping && inode->i_mapping->nrpages)
+ invalidate_inode_pages2(inode->i_mapping);
+
+ nfs_fscache_zap_fh_cookie(inode);
+ }
+}
+
+/*
+ * Decide if we should enable or disable the FS cache for this inode
+ * - For now, only regular files that are open read-only will be able to use
+ * the cache
+ */
+void nfs_fscache_set_fh_cookie(struct inode *inode, struct file *filp)
+{
+ if (NFS_FSCACHE(inode)) {
+ if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
+ nfs_fscache_disable_fh_cookie(inode);
+ else
+ nfs_fscache_enable_fh_cookie(inode);
+ }
+}
+
+/*
+ * Replace a per-filehandle cookie due to revalidation detecting a file having
+ * changed on the server
+ */
+void nfs_fscache_renew_fh_cookie(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct nfs_server *server = NFS_SERVER(inode);
+ struct fscache_cookie *old = nfsi->fscache;
+
+ if (nfsi->fscache) {
+ /* retire the current fscache cache and get a new one */
+ fscache_relinquish_cookie(nfsi->fscache, 1);
+
+ nfsi->fscache = fscache_acquire_cookie(
+ server->nfs_client->fscache,
+ &nfs_cache_fh_index_def,
+ nfsi);
+
+ dfprintk(FSCACHE,
+ "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
+ server, nfsi, old, nfsi->fscache);
+ }
+}
+
+/*
+ * change the filesize associated with a per-filehandle cookie
+ */
+void nfs_fscache_attr_changed(struct inode *inode)
+{
+ fscache_attr_changed(NFS_I(inode)->fscache);
+}
+
+/*
+ * Handle completion of a page being read from the cache
+ * - Called in process (keventd) context
+ */
+static void nfs_readpage_from_fscache_complete(struct page *page,
+ void *context,
+ int error)
+{
+ dfprintk(FSCACHE,
+ "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n",
+ page, context, error);
+
+ /* if the read completes with an error, we just unlock the page and let
+ * the VM reissue the readpage */
+ if (!error) {
+ SetPageUptodate(page);
+ unlock_page(page);
+ } else {
+ error = nfs_readpage_async(context, page->mapping->host, page);
+ if (error)
+ unlock_page(page);
+ }
+}
+
+/*
+ * 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);
+ atomic_inc(&nfs_fscache_uncache_page);
+ nfs_fscache_to_error = ret;
+ } else {
+ atomic_inc(&nfs_fscache_to_pages);
+ }
+}
+
+/*
+ * Retrieve a page from fscache
+ */
+int __nfs_readpage_from_fscache(struct nfs_open_context *ctx,
+ struct inode *inode, struct page *page)
+{
+ int ret;
+
+ dfprintk(FSCACHE,
+ "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
+ NFS_I(inode)->fscache, page, page->index, page->flags, inode);
+
+ ret = fscache_read_or_alloc_page(NFS_I(inode)->fscache,
+ page,
+ nfs_readpage_from_fscache_complete,
+ ctx,
+ GFP_KERNEL);
+
+ switch (ret) {
+ case 0: /* read BIO submitted (page in fscache) */
+ dfprintk(FSCACHE,
+ "NFS: readpage_from_fscache: BIO submitted\n");
+ atomic_inc(&nfs_fscache_from_pages);
+ return ret;
+
+ case -ENOBUFS: /* inode not in cache */
+ case -ENODATA: /* page not in cache */
+ dfprintk(FSCACHE,
+ "NFS: readpage_from_fscache error %d\n", ret);
+ return 1;
+
+ default:
+ dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret);
+ nfs_fscache_from_error = ret;
+ }
+ return ret;
+}
+
+/*
+ * Retrieve a set of pages from fscache
+ */
+int __nfs_readpages_from_fscache(struct nfs_open_context *ctx,
+ struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ int ret, npages = *nr_pages;
+
+ dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
+ NFS_I(inode)->fscache, npages, inode);
+
+ ret = fscache_read_or_alloc_pages(NFS_I(inode)->fscache,
+ mapping, pages, nr_pages,
+ nfs_readpage_from_fscache_complete,
+ ctx,
+ mapping_gfp_mask(mapping));
+
+
+ switch (ret) {
+ case 0: /* read BIO submitted (page in fscache) */
+ BUG_ON(!list_empty(pages));
+ BUG_ON(*nr_pages != 0);
+ dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache: submitted\n");
+
+ atomic_add(npages, &nfs_fscache_from_pages);
+ return ret;
+
+ case -ENOBUFS: /* inode not in cache */
+ case -ENODATA: /* page not in cache */
+ 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);
+ nfs_fscache_from_error = ret;
+ }
+
+ return ret;
+}
+
+/*
+ * Release the caching state associated with a page, if the page isn't busy
+ * interacting with the cache
+ * - Returns true (can release page) or false (page busy)
+ */
+int nfs_fscache_release_page(struct page *page, gfp_t gfp)
+{
+ if (PageFsCacheWrite(page)) {
+ if (!(gfp & __GFP_WAIT))
+ return 0;
+ wait_on_page_fscache_write(page);
+ }
+
+ if (PageFsCache(page)) {
+ struct nfs_inode *nfsi = NFS_I(page->mapping->host);
+
+ BUG_ON(!nfsi->fscache);
+
+ dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
+ nfsi->fscache, page, nfsi);
+
+ fscache_uncache_page(nfsi->fscache, page);
+ atomic_inc(&nfs_fscache_uncache_page);
+ }
+
+ return 1;
+}
+
+/*
+ * Release the caching state associated with a page if undergoing complete page
+ * invalidation
+ */
+void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(page->mapping->host);
+
+ BUG_ON(!nfsi->fscache);
+
+ dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n",
+ nfsi->fscache, page, nfsi);
+
+ wait_on_page_fscache_write(page);
+
+ BUG_ON(!PageLocked(page));
+ fscache_uncache_page(nfsi->fscache, page);
+ atomic_inc(&nfs_fscache_uncache_page);
+}
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
new file mode 100644
index 0000000..44bb0d1
--- /dev/null
+++ b/fs/nfs/fscache.h
@@ -0,0 +1,144 @@
+/* NFS filesystem cache interface definitions
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@xxxxxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _NFS_FSCACHE_H
+#define _NFS_FSCACHE_H
+
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+
+#ifdef CONFIG_NFS_FSCACHE
+#include <linux/fscache.h>
+
+/*
+ * fscache-def.c
+ */
+extern struct fscache_netfs nfs_cache_netfs;
+extern const struct fscache_cookie_def nfs_cache_server_index_def;
+extern const struct fscache_cookie_def nfs_cache_fh_index_def;
+
+extern int nfs_fscache_register(void);
+extern void nfs_fscache_unregister(void);
+
+/*
+ * fscache.c
+ */
+extern atomic_t nfs_fscache_to_pages;
+extern atomic_t nfs_fscache_from_pages;
+extern atomic_t nfs_fscache_uncache_page;
+extern int nfs_fscache_from_error;
+extern int nfs_fscache_to_error;
+
+extern void nfs_fscache_get_client_cookie(struct nfs_client *);
+extern void nfs_fscache_release_client_cookie(struct nfs_client *);
+extern void nfs_fscache_init_fh_cookie(struct inode *);
+extern void nfs_fscache_enable_fh_cookie(struct inode *);
+extern void nfs_fscache_release_fh_cookie(struct inode *);
+extern void nfs_fscache_zap_fh_cookie(struct inode *);
+extern void nfs_fscache_disable_fh_cookie(struct inode *);
+extern void nfs_fscache_set_fh_cookie(struct inode *, struct file *);
+extern void nfs_fscache_renew_fh_cookie(struct inode *);
+extern void nfs_fscache_attr_changed(struct inode *);
+extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
+extern int __nfs_readpage_from_fscache(struct nfs_open_context *, struct inode *, struct page *);
+extern int __nfs_readpages_from_fscache(struct nfs_open_context *, struct inode *,
+ struct address_space *, struct list_head *, unsigned *);
+extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
+extern int nfs_fscache_release_page(struct page *, gfp_t);
+
+/*
+ * release the caching state associated with a page if undergoing complete page
+ * invalidation
+ */
+static inline void nfs_fscache_invalidate_page(struct page *page,
+ struct inode *inode)
+{
+ if (PageFsCache(page))
+ __nfs_fscache_invalidate_page(page, inode);
+}
+
+/*
+ * store a newly fetched page in fscache
+ */
+static inline void nfs_readpage_to_fscache(struct inode *inode,
+ struct page *page,
+ int sync)
+{
+ if (PageFsCache(page))
+ __nfs_readpage_to_fscache(inode, page, sync);
+}
+
+/*
+ * retrieve a page from fscache
+ */
+static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
+ struct inode *inode,
+ struct page *page)
+{
+ if (NFS_I(inode)->fscache)
+ return __nfs_readpage_from_fscache(ctx, inode, page);
+ return -ENOBUFS;
+}
+
+/*
+ * retrieve a set of pages from fscache
+ */
+static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
+ struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ if (NFS_I(inode)->fscache)
+ return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
+ nr_pages);
+ return -ENOBUFS;
+}
+
+#else /* CONFIG_NFS_FSCACHE */
+static inline int nfs_fscache_register(void) { return 0; }
+static inline void nfs_fscache_unregister(void) {}
+static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
+static inline void nfs4_fscache_get_client_cookie(struct nfs_client *clp) {}
+static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
+
+static inline void nfs_fscache_init_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_enable_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_attr_changed(struct inode *inode) {}
+static inline void nfs_fscache_release_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_zap_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_renew_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_disable_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_set_fh_cookie(struct inode *inode, struct file *filp) {}
+static inline void nfs_fscache_install_vm_ops(struct inode *inode, struct vm_area_struct *vma) {}
+static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
+{
+ return 1; /* True: may release page */
+}
+static inline void nfs_fscache_invalidate_page(struct page *page, struct inode *inode) {}
+static inline void nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync) {}
+static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
+ struct inode *inode, struct page *page)
+{
+ return -ENOBUFS;
+}
+static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
+ struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ return -ENOBUFS;
+}
+
+#endif /* CONFIG_NFS_FSCACHE */
+#endif /* _NFS_FSCACHE_H */
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index c99f654..0cd2b84 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -46,6 +46,7 @@
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
+#include "fscache.h"

#define NFSDBG_FACILITY NFSDBG_VFS

@@ -88,6 +89,7 @@ void nfs_clear_inode(struct inode *inode)
BUG_ON(atomic_read(&NFS_I(inode)->data_updates) != 0);
nfs_zap_acl_cache(inode);
nfs_access_zap_cache(inode);
+ nfs_fscache_release_fh_cookie(inode);
}

/**
@@ -298,6 +300,8 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
nfsi->access_cache = RB_ROOT;

+ nfs_fscache_init_fh_cookie(inode);
+
unlock_new_inode(inode);
} else
nfs_refresh_inode(inode, fattr);
@@ -563,6 +567,7 @@ int nfs_open(struct inode *inode, struct file *filp)
ctx->mode = filp->f_mode;
nfs_file_set_open_context(filp, ctx);
put_nfs_open_context(ctx);
+ nfs_fscache_set_fh_cookie(inode, filp);
return 0;
}

@@ -629,7 +634,13 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
(long long)NFS_FILEID(inode), status);
goto out;
}
- spin_unlock(&inode->i_lock);
+ if (nfsi->cache_validity & NFS_INO_INVALID_FSCACHE_ATTR) {
+ nfsi->cache_validity &= ~NFS_INO_INVALID_FSCACHE_ATTR;
+ spin_unlock(&inode->i_lock);
+ nfs_fscache_attr_changed(inode);
+ } else {
+ spin_unlock(&inode->i_lock);
+ }

if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
nfs_zap_acl_cache(inode);
@@ -688,6 +699,7 @@ static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_spa
}
spin_unlock(&inode->i_lock);
nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
+ nfs_fscache_renew_fh_cookie(inode);
dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
inode->i_sb->s_id, (long long)NFS_FILEID(inode));
return 0;
@@ -888,7 +900,13 @@ int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
else
status = nfs_check_inode_attributes(inode, fattr);

- spin_unlock(&inode->i_lock);
+ if (nfsi->cache_validity & NFS_INO_INVALID_FSCACHE_ATTR) {
+ nfsi->cache_validity &= ~NFS_INO_INVALID_FSCACHE_ATTR;
+ spin_unlock(&inode->i_lock);
+ nfs_fscache_attr_changed(inode);
+ } else {
+ spin_unlock(&inode->i_lock);
+ }
return status;
}

@@ -918,7 +936,13 @@ int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
}
status = nfs_update_inode(inode, fattr);
out:
- spin_unlock(&inode->i_lock);
+ if (nfsi->cache_validity & NFS_INO_INVALID_FSCACHE_ATTR) {
+ nfsi->cache_validity &= ~NFS_INO_INVALID_FSCACHE_ATTR;
+ spin_unlock(&inode->i_lock);
+ nfs_fscache_attr_changed(inode);
+ } else {
+ spin_unlock(&inode->i_lock);
+ }
return status;
}

@@ -989,12 +1013,14 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
/* No, but did we race with nfs_end_data_update()? */
if (data_stable) {
inode->i_size = new_isize;
- invalid |= NFS_INO_INVALID_DATA;
+ invalid |= NFS_INO_INVALID_DATA |
+ NFS_INO_INVALID_FSCACHE_ATTR;
}
invalid |= NFS_INO_INVALID_ATTR;
} else if (new_isize > cur_isize) {
inode->i_size = new_isize;
- invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
+ invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA |
+ NFS_INO_INVALID_FSCACHE_ATTR;
}
nfsi->cache_change_attribute = now;
dprintk("NFS: isize change on server for file %s/%ld\n",
@@ -1006,7 +1032,8 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
dprintk("NFS: mtime change on server for file %s/%ld\n",
inode->i_sb->s_id, inode->i_ino);
- invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
+ invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA |
+ NFS_INO_INVALID_FSCACHE_ATTR;
nfsi->cache_change_attribute = now;
}

@@ -1059,7 +1086,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
/* Don't invalidate the data if we were to blame */
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
|| S_ISLNK(inode->i_mode)))
- invalid &= ~NFS_INO_INVALID_DATA;
+ invalid &= ~(NFS_INO_INVALID_DATA | NFS_INO_INVALID_FSCACHE_ATTR);
if (data_stable)
invalid &= ~(NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME|NFS_INO_REVAL_PAGECACHE);
if (!nfs_have_delegation(inode, FMODE_READ) ||
@@ -1181,6 +1208,10 @@ static int __init init_nfs_fs(void)
{
int err;

+ err = nfs_fscache_register();
+ if (err < 0)
+ goto out6;
+
err = nfs_fs_proc_init();
if (err)
goto out5;
@@ -1227,6 +1258,8 @@ out3:
out4:
nfs_fs_proc_exit();
out5:
+ nfs_fscache_unregister();
+out6:
return err;
}

@@ -1237,6 +1270,7 @@ static void __exit exit_nfs_fs(void)
nfs_destroy_readpagecache();
nfs_destroy_inodecache();
nfs_destroy_nfspagecache();
+ nfs_fscache_unregister();
#ifdef CONFIG_PROC_FS
rpc_proc_unregister("nfs");
#endif
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 19e0563..4dfd6dc 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -18,12 +18,14 @@
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
+#include <linux/nfs_mount.h>
#include <linux/smp_lock.h>

#include <asm/system.h>

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

#define NFSDBG_FACILITY NFSDBG_PAGECACHE

@@ -114,8 +116,8 @@ static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
}
}

-static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
- struct page *page)
+int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
+ struct page *page)
{
LIST_HEAD(one_request);
struct nfs_page *new;
@@ -142,6 +144,11 @@ static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,

static void nfs_readpage_release(struct nfs_page *req)
{
+ struct inode *d_inode = req->wb_context->path.dentry->d_inode;
+
+ if (PageUptodate(req->wb_page))
+ nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
+
unlock_page(req->wb_page);

dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
@@ -500,8 +507,15 @@ int nfs_readpage(struct file *file, struct page *page)
ctx = get_nfs_open_context((struct nfs_open_context *)
file->private_data);

+ if (!IS_SYNC(inode)) {
+ error = nfs_readpage_from_fscache(ctx, inode, page);
+ if (error == 0)
+ goto out;
+ }
+
error = nfs_readpage_async(ctx, inode, page);

+out:
put_nfs_open_context(ctx);
return error;
out_unlock:
@@ -578,6 +592,15 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
} else
desc.ctx = get_nfs_open_context((struct nfs_open_context *)
filp->private_data);
+
+ /* attempt to read as many of the pages as possible from the cache
+ * - this returns -ENOBUFS immediately if the cookie is negative
+ */
+ ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
+ pages, &nr_pages);
+ if (ret == 0)
+ goto read_complete; /* all pages were read */
+
if (rsize < PAGE_CACHE_SIZE)
nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);
else
@@ -588,6 +611,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
nfs_pageio_complete(&pgio);
npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
nfs_add_stats(inode, NFSIOS_READPAGES, npages);
+read_complete:
put_nfs_open_context(desc.ctx);
out:
return ret;
diff --git a/fs/nfs/sysctl.c b/fs/nfs/sysctl.c
index b62481d..9eaf5a9 100644
--- a/fs/nfs/sysctl.c
+++ b/fs/nfs/sysctl.c
@@ -14,6 +14,8 @@
#include <linux/nfs_fs.h>

#include "callback.h"
+#include "internal.h"
+#include "fscache.h"

static const int nfs_set_port_min = 0;
static const int nfs_set_port_max = 65535;
@@ -58,6 +60,48 @@ static ctl_table nfs_cb_sysctls[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+#ifdef CONFIG_NFS_FSCACHE
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "fscache_from_error",
+ .data = &nfs_fscache_from_error,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "fscache_to_error",
+ .data = &nfs_fscache_to_error,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "fscache_uncache_page",
+ .data = &nfs_fscache_uncache_page,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "fscache_to_pages",
+ .data = &nfs_fscache_to_pages,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ },
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "fscache_from_pages",
+ .data = &nfs_fscache_from_pages,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+#endif
{ .ctl_name = 0 }
};

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 7250eea..19419bc 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -172,6 +172,9 @@ struct nfs_inode {
int delegation_state;
struct rw_semaphore rwsem;
#endif /* CONFIG_NFS_V4*/
+#ifdef CONFIG_NFS_FSCACHE
+ struct fscache_cookie *fscache;
+#endif
struct inode vfs_inode;
};

@@ -185,6 +188,7 @@ struct nfs_inode {
#define NFS_INO_INVALID_ACL 0x0010 /* cached acls are invalid */
#define NFS_INO_REVAL_PAGECACHE 0x0020 /* must revalidate pagecache */
#define NFS_INO_REVAL_FORCED 0x0040 /* force revalidation ignoring a delegation */
+#define NFS_INO_INVALID_FSCACHE_ATTR 0x0080 /* local cache attributes are invalid */

/*
* Bit offsets in flags field
@@ -193,6 +197,7 @@ struct nfs_inode {
#define NFS_INO_ADVISE_RDPLUS (1) /* advise readdirplus */
#define NFS_INO_STALE (2) /* possible stale inode */
#define NFS_INO_ACL_LRU_SET (3) /* Inode is on the LRU list */
+#define NFS_INO_FSCACHE (4) /* inode can be cached by FS-Cache */

static inline struct nfs_inode *NFS_I(struct inode *inode)
{
@@ -218,6 +223,7 @@ static inline struct nfs_inode *NFS_I(struct inode *inode)

#define NFS_FLAGS(inode) (NFS_I(inode)->flags)
#define NFS_STALE(inode) (test_bit(NFS_INO_STALE, &NFS_FLAGS(inode)))
+#define NFS_FSCACHE(inode) (test_bit(NFS_INO_FSCACHE, &NFS_FLAGS(inode)))

#define NFS_FILEID(inode) (NFS_I(inode)->fileid)

@@ -464,6 +470,7 @@ extern int nfs_readpages(struct file *, struct address_space *,
struct list_head *, unsigned);
extern int nfs_readpage_result(struct rpc_task *, struct nfs_read_data *);
extern void nfs_readdata_release(void *data);
+extern int nfs_readpage_async(struct nfs_open_context *, struct inode *, struct page *);

/*
* Allocate nfs_read_data structures
@@ -554,6 +561,7 @@ extern void * nfs_root_data(void);
#define NFSDBG_CALLBACK 0x0100
#define NFSDBG_CLIENT 0x0200
#define NFSDBG_MOUNT 0x0400
+#define NFSDBG_FSCACHE 0x0800
#define NFSDBG_ALL 0xFFFF

#ifdef __KERNEL__
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 0cac49b..95d0617 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -3,6 +3,7 @@

#include <linux/list.h>
#include <linux/backing-dev.h>
+#include <linux/fscache.h>

struct nfs_iostats;

@@ -65,6 +66,10 @@ struct nfs_client {
char cl_ipaddr[16];
unsigned char cl_id_uniquifier;
#endif
+
+#ifdef CONFIG_NFS_FSCACHE
+ struct fscache_cookie *fscache; /* client index cache cookie */
+#endif
};

/*
@@ -95,6 +100,8 @@ struct nfs_server {
unsigned int acdirmin;
unsigned int acdirmax;
unsigned int namelen;
+ unsigned int options; /* extra options enabled by mount */
+#define NFS_OPTION_FSCACHE 0x00000001 /* - local caching enabled */

struct nfs_fsid fsid;
__u64 maxfilesize; /* maximum file size */

-
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