[PATCH 61/67] nfs: Convert to new fscache volume/cookie API

David Howells
2021-10-18T15:08:25Z

Change the nfs filesystem to support fscache's indexing rewrite and
reenable caching in nfs.

The following changes have been made:

(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.

(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.

For nfs, I've made it render the volume name string as:

"nfs,<ver>,<family>, ,<port>,<fsidH>,<fsidL>*<,param>[,<uniq>]"

(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.

fscache_acquire_cookie() is passed the same keying and coherency
information as before.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Dave Wysochanski <dwysocha@redhat.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: Anna Schumaker <anna.schumaker@netapp.com>
cc: linux-nfs@vger.kernel.org
---

fs/nfs/Kconfig | 2
fs/nfs/Makefile | 2
fs/nfs/client.c | 4 -
fs/nfs/fscache-index.c | 46 ---------
fs/nfs/fscache.c | 220 ++++++++++++++-------------------------------
fs/nfs/fscache.h | 56 -----------
fs/nfs/inode.c | 7 -
fs/nfs/super.c | 7 +
include/linux/nfs_fs_sb.h | 9 --
9 files changed, 74 insertions(+), 279 deletions(-)
delete mode 100644 fs/nfs/fscache-index.c

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index a8b73c90aa00..14a72224b657 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -170,7 +170,7 @@ config ROOT_NFS

config NFS_FSCACHE
bool "Provide NFS client caching support"
- depends on NFS_FS=m && FSCACHE_OLD || NFS_FS=y && FSCACHE_OLD=y
+ depends on NFS_FS=m && FSCACHE || NFS_FS=y && FSCACHE=y
help
Say Y here if you want NFS data to be cached locally on disc through
the general filesystem cache manager
diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index 22d11fdc6deb..5f6db37f461e 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -12,7 +12,7 @@ nfs-y := client.o dir.o file.o getroot.o inode.o super.o \
export.o sysfs.o fs_context.o
nfs-$(CONFIG_ROOT_NFS) += nfsroot.o
nfs-$(CONFIG_SYSCTL) += sysctl.o
-nfs-$(CONFIG_NFS_FSCACHE) += fscache.o fscache-index.o
+nfs-$(CONFIG_NFS_FSCACHE) += fscache.o

obj-$(CONFIG_NFS_V2) += nfsv2.o
nfsv2-y := nfs2super.o proc.o nfs2xdr.o
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 23e165d5ec9c..8f35e26d8a29 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -183,8 +183,6 @@ struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
clp->cl_net = get_net(cl_init->net);

clp->cl_principal = "*";
- nfs_fscache_get_client_cookie(clp);
-
return clp;

error_cleanup:
@@ -238,8 +236,6 @@ static void pnfs_init_server(struct nfs_server *server)
*/
void nfs_free_client(struct nfs_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/fscache-index.c b/fs/nfs/fscache-index.c
deleted file mode 100644
index b4fdacd955f3..000000000000
--- a/fs/nfs/fscache-index.c
+++ /dev/null
@@ -1,46 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* NFS FS-Cache index structure definition
- *
- * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
-
-#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/iversion.h>
-
-#include "internal.h"
-#include "fscache.h"
-
-#define NFSDBG_FACILITY NFSDBG_FSCACHE
-
-/*
- * Define the NFS filesystem for FS-Cache. Upon registration FS-Cache sticks
- * the cookie for the top-level index object for NFS into here. The top-level
- * index can than have other cache objects inserted into it.
- */
-struct fscache_netfs nfs_fscache_netfs = {
- .name = "nfs",
- .version = 0,
-};
-
-/*
- * Register NFS for caching
- */
-int nfs_fscache_register(void)
-{
- return fscache_register_netfs(&nfs_fscache_netfs);
-}
-
-/*
- * Unregister NFS for caching
- */
-void nfs_fscache_unregister(void)
-{
- fscache_unregister_netfs(&nfs_fscache_netfs);
-}
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index 8250a029759e..c15bdf3606eb 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -22,24 +22,18 @@

#define NFSDBG_FACILITY NFSDBG_FSCACHE

-static struct rb_root nfs_fscache_keys = RB_ROOT;
-static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
+#define NFS_MAX_KEY_LEN 1000

-/*
- * Layout of the key for an NFS server cache object.
- */
-struct nfs_server_key {
- struct {
- uint16_t nfsversion; /* NFS protocol version */
- uint32_t minorversion; /* NFSv4 minor version */
- uint16_t family; /* address family */
- __be16 port; /* IP port */
- } hdr;
- union {
- struct in_addr ipv4_addr; /* IPv4 address */
- struct in6_addr ipv6_addr; /* IPv6 address */
- };
-} __packed;
+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
@@ -47,68 +41,43 @@ struct nfs_server_key {
* - 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)
+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;
- struct nfs_server_key key;
- uint16_t len = sizeof(key.hdr);

- memset(&key, 0, sizeof(key));
- key.hdr.nfsversion = clp->rpc_ops->version;
- key.hdr.minorversion = clp->cl_minorversion;
- key.hdr.family = clp->cl_addr.ss_family;
+ *_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:
- key.hdr.port = sin->sin_port;
- key.ipv4_addr = sin->sin_addr;
- len += sizeof(key.ipv4_addr);
- break;
+ 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:
- key.hdr.port = sin6->sin6_port;
- key.ipv6_addr = sin6->sin6_addr;
- len += sizeof(key.ipv6_addr);
- break;
+ 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);
- clp->fscache = NULL;
- return;
+ return false;
}
-
- /* create a cache index for looking up filehandles */
- clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
- FSCACHE_COOKIE_TYPE_INDEX,
- "NFS.server",
- 0, /* advice */
- NULL, /* preferred_cache */
- &key, /* index_key */
- len,
- NULL, /* aux_data */
- 0,
- 0);
- 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, false);
- clp->fscache = NULL;
-}
-
-/*
- * Get the cache cookie for an NFS superblock. We have to handle
- * uniquification here because the cache doesn't do it for us.
+ * 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
@@ -116,100 +85,53 @@ void nfs_fscache_release_client_cookie(struct nfs_client *clp)
*/
void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
{
- struct nfs_fscache_key *key, *xkey;
struct nfs_server *nfss = NFS_SB(sb);
- struct rb_node **p, *parent;
- int diff;
+ unsigned int len = 3;
+ char *key;

- nfss->fscache_key = NULL;
- nfss->fscache = NULL;
- if (!uniq) {
- uniq = "";
- ulen = 1;
+ if (uniq) {
+ nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
+ if (!nfss->fscache_uniq)
+ return;
}

- key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
+ key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
if (!key)
return;

- key->nfs_client = nfss->nfs_client;
- key->key.super.s_flags = sb->s_flags & NFS_SB_MASK;
- key->key.nfs_server.flags = nfss->flags;
- key->key.nfs_server.rsize = nfss->rsize;
- key->key.nfs_server.wsize = nfss->wsize;
- key->key.nfs_server.acregmin = nfss->acregmin;
- key->key.nfs_server.acregmax = nfss->acregmax;
- key->key.nfs_server.acdirmin = nfss->acdirmin;
- key->key.nfs_server.acdirmax = nfss->acdirmax;
- key->key.nfs_server.fsid = nfss->fsid;
- key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
-
- key->key.uniq_len = ulen;
- memcpy(key->key.uniquifier, uniq, ulen);
-
- spin_lock(&nfs_fscache_keys_lock);
- p = &nfs_fscache_keys.rb_node;
- parent = NULL;
- while (*p) {
- parent = *p;
- xkey = rb_entry(parent, struct nfs_fscache_key, node);
-
- if (key->nfs_client < xkey->nfs_client)
- goto go_left;
- if (key->nfs_client > xkey->nfs_client)
- goto go_right;
-
- diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
- if (diff < 0)
- goto go_left;
- if (diff > 0)
- goto go_right;
-
- if (key->key.uniq_len == 0)
- goto non_unique;
- diff = memcmp(key->key.uniquifier,
- xkey->key.uniquifier,
- key->key.uniq_len);
- if (diff < 0)
- goto go_left;
- if (diff > 0)
- goto go_right;
- goto non_unique;
-
- go_left:
- p = &(*p)->rb_left;
- continue;
- go_right:
- p = &(*p)->rb_right;
+ 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;
}
-
- rb_link_node(&key->node, parent, p);
- rb_insert_color(&key->node, &nfs_fscache_keys);
- spin_unlock(&nfs_fscache_keys_lock);
- nfss->fscache_key = key;
+ key[len] = 0;

/* create a cache index for looking up filehandles */
- nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
- FSCACHE_COOKIE_TYPE_INDEX,
- "NFS.super",
- 0, /* advice */
+ nfss->fscache = fscache_acquire_volume(key,
NULL, /* preferred_cache */
- &key->key, /* index_key */
- sizeof(key->key) + ulen,
- NULL, /* aux_data */
- 0,
- 0);
+ 0 /* coherency_data */);
dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
nfss, nfss->fscache);
- return;

-non_unique:
- spin_unlock(&nfs_fscache_keys_lock);
+out:
kfree(key);
- nfss->fscache_key = NULL;
- nfss->fscache = NULL;
- printk(KERN_WARNING "NFS:"
- " Cache request denied due to non-unique superblock keys\n");
}

/*
@@ -222,16 +144,9 @@ void nfs_fscache_release_super_cookie(struct super_block *sb)
dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
nfss, nfss->fscache);

- fscache_relinquish_cookie(nfss->fscache, false);
+ fscache_relinquish_volume(nfss->fscache, 0, false);
nfss->fscache = NULL;
-
- if (nfss->fscache_key) {
- spin_lock(&nfs_fscache_keys_lock);
- rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
- spin_unlock(&nfs_fscache_keys_lock);
- kfree(nfss->fscache_key);
- nfss->fscache_key = NULL;
- }
+ kfree(nfss->fscache_uniq);
}

/*
@@ -250,10 +165,7 @@ void nfs_fscache_init_inode(struct inode *inode)
nfs_fscache_update_auxdata(&auxdata, nfsi);

nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache,
- FSCACHE_COOKIE_TYPE_DATAFILE,
- "NFS.fh",
- 0, /* advice */
- NULL, /* preferred_cache */
+ FSCACHE_ADV_FALLBACK_IO,
nfsi->fh.data, /* index_key */
nfsi->fh.size,
&auxdata, /* aux_data */
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index cc94b257059b..0cf2fbe30051 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -17,43 +17,6 @@

#ifdef CONFIG_NFS_FSCACHE

-/*
- * set of NFS FS-Cache objects that form a superblock key
- */
-struct nfs_fscache_key {
- struct rb_node node;
- struct nfs_client *nfs_client; /* the server */
-
- /* the elements of the unique key - as used by nfs_compare_super() and
- * nfs_compare_mount_options() to distinguish superblocks */
- struct {
- struct {
- unsigned long s_flags; /* various flags
- * (& NFS_MS_MASK) */
- } super;
-
- struct {
- struct nfs_fsid fsid;
- int flags;
- unsigned int rsize; /* read size */
- unsigned int wsize; /* write size */
- unsigned int acregmin; /* attr cache timeouts */
- unsigned int acregmax;
- unsigned int acdirmin;
- unsigned int acdirmax;
- } nfs_server;
-
- struct {
- rpc_authflavor_t au_flavor;
- } rpc_auth;
-
- /* uniquifier - can be used if nfs_server.flags includes
- * NFS_MOUNT_UNSHARED */
- u8 uniq_len;
- char uniquifier[0];
- } key;
-};
-
/*
* Definition of the auxiliary data attached to NFS inode storage objects
* within the cache.
@@ -71,20 +34,9 @@ struct nfs_fscache_inode_auxdata {
u64 change_attr;
};

-/*
- * fscache-index.c
- */
-extern struct fscache_netfs nfs_fscache_netfs;
-
-extern int nfs_fscache_register(void);
-extern void nfs_fscache_unregister(void);
-
/*
* fscache.c
*/
-extern void nfs_fscache_get_client_cookie(struct nfs_client *);
-extern void nfs_fscache_release_client_cookie(struct nfs_client *);
-
extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
extern void nfs_fscache_release_super_cookie(struct super_block *);

@@ -120,7 +72,7 @@ static inline void nfs_readpage_to_fscache(struct inode *inode,
}

static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
- struct nfs_inode *nfsi)
+ struct nfs_inode *nfsi)
{
memset(auxdata, 0, sizeof(*auxdata));
auxdata->mtime_sec = nfsi->vfs_inode.i_mtime.tv_sec;
@@ -158,12 +110,6 @@ static inline const char *nfs_server_fscache_state(struct nfs_server *server)
}

#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 nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
-
static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}

static inline void nfs_fscache_init_inode(struct inode *inode) {}
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 370c49b98646..1cfc8f5c9fe2 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -2361,10 +2361,6 @@ static int __init init_nfs_fs(void)
if (err < 0)
goto out9;

- err = nfs_fscache_register();
- if (err < 0)
- goto out8;
-
err = nfsiod_start();
if (err)
goto out7;
@@ -2416,8 +2412,6 @@ static int __init init_nfs_fs(void)
out6:
nfsiod_stop();
out7:
- nfs_fscache_unregister();
-out8:
unregister_pernet_subsys(&nfs_net_ops);
out9:
nfs_sysfs_exit();
@@ -2432,7 +2426,6 @@ static void __exit exit_nfs_fs(void)
nfs_destroy_readpagecache();
nfs_destroy_inodecache();
nfs_destroy_nfspagecache();
- nfs_fscache_unregister();
unregister_pernet_subsys(&nfs_net_ops);
rpc_proc_unregister(&init_net, "nfs");
unregister_nfs_fs();
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index e65c83494c05..e73d4adba50f 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1206,7 +1206,6 @@ static void nfs_get_cache_cookie(struct super_block *sb,
char *uniq = NULL;
int ulen = 0;

- nfss->fscache_key = NULL;
nfss->fscache = NULL;

if (!ctx)
@@ -1216,9 +1215,9 @@ static void nfs_get_cache_cookie(struct super_block *sb,
struct nfs_server *mnt_s = NFS_SB(ctx->clone_data.sb);
if (!(mnt_s->options & NFS_OPTION_FSCACHE))
return;
- if (mnt_s->fscache_key) {
- uniq = mnt_s->fscache_key->key.uniquifier;
- ulen = mnt_s->fscache_key->key.uniq_len;
+ if (mnt_s->fscache_uniq) {
+ uniq = mnt_s->fscache_uniq;
+ ulen = strlen(uniq);
}
} else {
if (!(ctx->options & NFS_OPTION_FSCACHE))
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 2a9acbfe00f0..77b2dba27bbb 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -120,11 +120,6 @@ struct nfs_client {
* This is used to generate the mv0 callback address.
*/
char cl_ipaddr[48];
-
-#ifdef CONFIG_NFS_FSCACHE
- struct fscache_cookie *fscache; /* client index cache cookie */
-#endif
-
struct net *cl_net;
struct list_head pending_cb_stateids;
};
@@ -194,8 +189,8 @@ struct nfs_server {
struct nfs_auth_info auth_info; /* parsed auth flavors */

#ifdef CONFIG_NFS_FSCACHE
- struct nfs_fscache_key *fscache_key; /* unique key for superblock */
- struct fscache_cookie *fscache; /* superblock cookie */
+ struct fscache_volume *fscache; /* superblock cookie */
+ char *fscache_uniq; /* Uniquifier (or NULL) */
#endif

u32 pnfs_blksize; /* layout_blksize attr */