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Subject[PATCH 4/6] NFS: DNS resolver cache per network namespace context introduced
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This patch implements DNS resolver cache creation and registration for each
alive network namespace context.
This was done by registering NFS per-net operations, responsible for DNS cache
allocation/register and unregister/destructioning instead of initialization and
destruction of static "nfs_dns_resolve" cache detail (this one was removed).
Pointer to network dns resolver cache is stored in new per-net "nfs_net"
structure.
This patch also changes nfs_dns_resolve_name() function prototype (and it's
calls) by adding network pointer parameter, which is used to get proper DNS
resolver cache pointer for do_cache_lookup_wait() call.

Note: empty nfs_dns_resolver_init() and nfs_dns_resolver_destroy() functions
will be used in next patch in the series.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
fs/nfs/dns_resolve.c | 96 ++++++++++++++++++++++++++++++++----------------
fs/nfs/dns_resolve.h | 14 ++++++-
fs/nfs/inode.c | 33 +++++++++++++++--
fs/nfs/netns.h | 13 +++++++
fs/nfs/nfs4namespace.c | 8 +++-
5 files changed, 123 insertions(+), 41 deletions(-)
create mode 100644 fs/nfs/netns.h

diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 3cbf4b8..9aea78a 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -11,7 +11,7 @@
#include <linux/sunrpc/clnt.h>
#include <linux/dns_resolver.h>

-ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
+ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
struct sockaddr *sa, size_t salen)
{
ssize_t ret;
@@ -43,12 +43,11 @@ ssize_t nfs_dns_resolve_name(char *name, size_t namelen,

#include "dns_resolve.h"
#include "cache_lib.h"
+#include "netns.h"

#define NFS_DNS_HASHBITS 4
#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)

-static struct cache_head *nfs_dns_table[NFS_DNS_HASHTBL_SIZE];
-
struct nfs_dns_ent {
struct cache_head h;

@@ -259,21 +258,6 @@ out:
return ret;
}

-static struct cache_detail nfs_dns_resolve = {
- .owner = THIS_MODULE,
- .hash_size = NFS_DNS_HASHTBL_SIZE,
- .hash_table = nfs_dns_table,
- .name = "dns_resolve",
- .cache_put = nfs_dns_ent_put,
- .cache_upcall = nfs_dns_upcall,
- .cache_parse = nfs_dns_parse,
- .cache_show = nfs_dns_show,
- .match = nfs_dns_match,
- .init = nfs_dns_ent_init,
- .update = nfs_dns_ent_update,
- .alloc = nfs_dns_ent_alloc,
-};
-
static int do_cache_lookup(struct cache_detail *cd,
struct nfs_dns_ent *key,
struct nfs_dns_ent **item,
@@ -336,8 +320,8 @@ out:
return ret;
}

-ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
- struct sockaddr *sa, size_t salen)
+ssize_t nfs_dns_resolve_name(struct net *net, char *name,
+ size_t namelen, struct sockaddr *sa, size_t salen)
{
struct nfs_dns_ent key = {
.hostname = name,
@@ -345,37 +329,83 @@ ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
};
struct nfs_dns_ent *item = NULL;
ssize_t ret;
+ struct nfs_net *nn = net_generic(net, nfs_net_id);

- ret = do_cache_lookup_wait(&nfs_dns_resolve, &key, &item);
+ ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
if (ret == 0) {
if (salen >= item->addrlen) {
memcpy(sa, &item->addr, item->addrlen);
ret = item->addrlen;
} else
ret = -EOVERFLOW;
- cache_put(&item->h, &nfs_dns_resolve);
+ cache_put(&item->h, nn->nfs_dns_resolve);
} else if (ret == -ENOENT)
ret = -ESRCH;
return ret;
}

-int nfs_dns_resolver_init(void)
+int nfs_dns_resolver_cache_init(struct net *net)
{
- int err;
+ int err = -ENOMEM;
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+ struct cache_detail *cd;
+ struct cache_head **tbl;
+
+ cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL);
+ if (cd == NULL)
+ goto err_cd;
+
+ tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *),
+ GFP_KERNEL);
+ if (tbl == NULL)
+ goto err_tbl;
+
+ cd->owner = THIS_MODULE,
+ cd->hash_size = NFS_DNS_HASHTBL_SIZE,
+ cd->hash_table = tbl,
+ cd->name = "dns_resolve",
+ cd->cache_put = nfs_dns_ent_put,
+ cd->cache_upcall = nfs_dns_upcall,
+ cd->cache_parse = nfs_dns_parse,
+ cd->cache_show = nfs_dns_show,
+ cd->match = nfs_dns_match,
+ cd->init = nfs_dns_ent_init,
+ cd->update = nfs_dns_ent_update,
+ cd->alloc = nfs_dns_ent_alloc,
+
+ nfs_cache_init(cd);
+ err = nfs_cache_register_net(net, cd);
+ if (err)
+ goto err_reg;
+ nn->nfs_dns_resolve = cd;
+ return 0;

- nfs_cache_init(&nfs_dns_resolve);
- err = nfs_cache_register_net(&init_net, &nfs_dns_resolve);
- if (err) {
- nfs_cache_destroy(&nfs_dns_resolve);
- return err;
- }
+err_reg:
+ nfs_cache_destroy(cd);
+ kfree(cd->hash_table);
+err_tbl:
+ kfree(cd);
+err_cd:
+ return err;
+}
+
+void nfs_dns_resolver_cache_destroy(struct net *net)
+{
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+ struct cache_detail *cd = nn->nfs_dns_resolve;
+
+ nfs_cache_unregister_net(net, cd);
+ nfs_cache_destroy(cd);
+ kfree(cd->hash_table);
+ kfree(cd);
+}
+
+int nfs_dns_resolver_init(void)
+{
return 0;
}

void nfs_dns_resolver_destroy(void)
{
- nfs_cache_unregister_net(&init_net, &nfs_dns_resolve);
- nfs_cache_destroy(&nfs_dns_resolve);
}
-
#endif
diff --git a/fs/nfs/dns_resolve.h b/fs/nfs/dns_resolve.h
index 199bb55..2e4f596 100644
--- a/fs/nfs/dns_resolve.h
+++ b/fs/nfs/dns_resolve.h
@@ -15,12 +15,22 @@ static inline int nfs_dns_resolver_init(void)

static inline void nfs_dns_resolver_destroy(void)
{}
+
+static inline int nfs_dns_resolver_cache_init(struct net *net)
+{
+ return 0;
+}
+
+static inline void nfs_dns_resolver_cache_destroy(struct net *net)
+{}
#else
extern int nfs_dns_resolver_init(void);
extern void nfs_dns_resolver_destroy(void);
+extern int nfs_dns_resolver_cache_init(struct net *net);
+extern void nfs_dns_resolver_cache_destroy(struct net *net);
#endif

-extern ssize_t nfs_dns_resolve_name(char *name, size_t namelen,
- struct sockaddr *sa, size_t salen);
+extern ssize_t nfs_dns_resolve_name(struct net *net, char *name,
+ size_t namelen, struct sockaddr *sa, size_t salen);

#endif
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index fe12037..84d8506 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -50,6 +50,7 @@
#include "fscache.h"
#include "dns_resolve.h"
#include "pnfs.h"
+#include "netns.h"

#define NFSDBG_FACILITY NFSDBG_VFS

@@ -1550,6 +1551,25 @@ static void nfsiod_stop(void)
destroy_workqueue(wq);
}

+int nfs_net_id;
+
+static int nfs_net_init(struct net *net)
+{
+ return nfs_dns_resolver_cache_init(net);
+}
+
+static void nfs_net_exit(struct net *net)
+{
+ nfs_dns_resolver_cache_destroy(net);
+}
+
+static struct pernet_operations nfs_net_ops = {
+ .init = nfs_net_init,
+ .exit = nfs_net_exit,
+ .id = &nfs_net_id,
+ .size = sizeof(struct nfs_net),
+};
+
/*
* Initialize NFS
*/
@@ -1559,10 +1579,14 @@ static int __init init_nfs_fs(void)

err = nfs_idmap_init();
if (err < 0)
- goto out9;
+ goto out10;

err = nfs_dns_resolver_init();
if (err < 0)
+ goto out9;
+
+ err = register_pernet_subsys(&nfs_net_ops);
+ if (err < 0)
goto out8;

err = nfs_fscache_register();
@@ -1623,10 +1647,12 @@ out5:
out6:
nfs_fscache_unregister();
out7:
- nfs_dns_resolver_destroy();
+ unregister_pernet_subsys(&nfs_net_ops);
out8:
- nfs_idmap_quit();
+ nfs_dns_resolver_destroy();
out9:
+ nfs_idmap_quit();
+out10:
return err;
}

@@ -1638,6 +1664,7 @@ static void __exit exit_nfs_fs(void)
nfs_destroy_inodecache();
nfs_destroy_nfspagecache();
nfs_fscache_unregister();
+ unregister_pernet_subsys(&nfs_net_ops);
nfs_dns_resolver_destroy();
nfs_idmap_quit();
#ifdef CONFIG_PROC_FS
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
new file mode 100644
index 0000000..8c1f130
--- /dev/null
+++ b/fs/nfs/netns.h
@@ -0,0 +1,13 @@
+#ifndef __NFS_NETNS_H__
+#define __NFS_NETNS_H__
+
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+struct nfs_net {
+ struct cache_detail *nfs_dns_resolve;
+};
+
+extern int nfs_net_id;
+
+#endif
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index bb80c49..919a369 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -94,13 +94,14 @@ static int nfs4_validate_fspath(struct dentry *dentry,
}

static size_t nfs_parse_server_name(char *string, size_t len,
- struct sockaddr *sa, size_t salen)
+ struct sockaddr *sa, size_t salen, struct nfs_server *server)
{
ssize_t ret;

ret = rpc_pton(string, len, sa, salen);
if (ret == 0) {
- ret = nfs_dns_resolve_name(string, len, sa, salen);
+ ret = nfs_dns_resolve_name(server->client->cl_xprt->xprt_net,
+ string, len, sa, salen);
if (ret < 0)
ret = 0;
}
@@ -137,7 +138,8 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
continue;

mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
- mountdata->addr, addr_bufsize);
+ mountdata->addr, addr_bufsize,
+ NFS_SB(mountdata->sb));
if (mountdata->addrlen == 0)
continue;



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