Refactor nfs_compare_super() and add AF_INET6 support.
Replace the generic memcmp() to document explicitly what parts of the
addresses must match in this check, and make the comparison independent
of the lengths of both addresses.
A side benefit is both tests are more computationally efficient than a
memcmp().
Note the "void *" casts are temporary.
Signed-off-by: Chuck Lever <[email protected]>
---
fs/nfs/super.c | 41 ++++++++++++++++++++++++++++++++++++++---
1 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 6b004d8..e5646a9 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -45,6 +45,8 @@
#include <linux/nfs_idmap.h>
#include <linux/vfs.h>
#include <linux/inet.h>
+#include <linux/in6.h>
+#include <net/ipv6.h>
#include <linux/nfs_xdr.h>
#include <linux/magic.h>
#include <linux/parser.h>
@@ -1302,15 +1304,48 @@ static int nfs_set_super(struct super_block *s, void *data)
return ret;
}
+static int nfs_compare_super_address(struct nfs_server *server1,
+ struct nfs_server *server2)
+{
+ struct sockaddr_storage *ssp1 = (void *)&server1->nfs_client->cl_addr;
+ struct sockaddr_storage *ssp2 = (void *)&server2->nfs_client->cl_addr;
+
+ if (ssp1->ss_family != ssp2->ss_family)
+ return 0;
+
+ switch (ssp1->ss_family) {
+ case AF_INET: {
+ struct sockaddr_in *sin1 = (struct sockaddr_in *)ssp1;
+ struct sockaddr_in *sin2 = (struct sockaddr_in *)ssp2;
+ if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
+ return 0;
+ if (sin1->sin_port != sin2->sin_port)
+ return 0;
+ break;
+ }
+ case AF_INET6: {
+ struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)ssp1;
+ struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)ssp2;
+ if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
+ return 0;
+ if (sin1->sin6_port != sin2->sin6_port)
+ return 0;
+ break;
+ }
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
static int nfs_compare_super(struct super_block *sb, void *data)
{
struct nfs_sb_mountdata *sb_mntdata = data;
struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
int mntflags = sb_mntdata->mntflags;
- if (memcmp(&old->nfs_client->cl_addr,
- &server->nfs_client->cl_addr,
- sizeof(old->nfs_client->cl_addr)) != 0)
+ if (!nfs_compare_super_address(old, server))
return 0;
/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
if (old->flags & NFS_MOUNT_UNSHARED)
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On Nov 30, 2007, at 2:17 PM, Trond Myklebust wrote:
>
> On Fri, 2007-11-30 at 14:12 -0500, Chuck Lever wrote:
>> Refactor nfs_compare_super() and add AF_INET6 support.
>>
>> Replace the generic memcmp() to document explicitly what parts of the
>> addresses must match in this check, and make the comparison
>> independent
>> of the lengths of both addresses.
>>
>> A side benefit is both tests are more computationally efficient
>> than a
>> memcmp().
>>
>> Note the "void *" casts are temporary.
>>
>> Signed-off-by: Chuck Lever <[email protected]>
>> ---
>>
>> fs/nfs/super.c | 41 ++++++++++++++++++++++++++++++++++++++---
>> 1 files changed, 38 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>> index 6b004d8..e5646a9 100644
>> --- a/fs/nfs/super.c
>> +++ b/fs/nfs/super.c
>> @@ -45,6 +45,8 @@
>> #include <linux/nfs_idmap.h>
>> #include <linux/vfs.h>
>> #include <linux/inet.h>
>> +#include <linux/in6.h>
>> +#include <net/ipv6.h>
>> #include <linux/nfs_xdr.h>
>> #include <linux/magic.h>
>> #include <linux/parser.h>
>> @@ -1302,15 +1304,48 @@ static int nfs_set_super(struct
>> super_block *s, void *data)
>> return ret;
>> }
>>
>> +static int nfs_compare_super_address(struct nfs_server *server1,
>> + struct nfs_server *server2)
>> +{
>> + struct sockaddr_storage *ssp1 = (void *)&server1->nfs_client-
>> >cl_addr;
>> + struct sockaddr_storage *ssp2 = (void *)&server2->nfs_client-
>> >cl_addr;
>> +
>> + if (ssp1->ss_family != ssp2->ss_family)
>> + return 0;
>> +
>> + switch (ssp1->ss_family) {
>> + case AF_INET: {
>> + struct sockaddr_in *sin1 = (struct sockaddr_in *)ssp1;
>> + struct sockaddr_in *sin2 = (struct sockaddr_in *)ssp2;
>> + if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
>> + return 0;
>> + if (sin1->sin_port != sin2->sin_port)
>
> What if sin2->sin_port == 0?
The original comparison in nfs_compare_super() uses a memcmp() to
compare sizeof(struct sockaddr_in) bytes, which would include the
sin_port field of both addresses, right? Thus the original
comparison would find a match when sin2->sin_port is zero only if
sin1->sin_port is also zero.
AFAICT, the comparisons in nfs_compare_super_address() provide
precisely the same check as the memcmp() in the original.
>> + return 0;
>> + break;
>> + }
>> + case AF_INET6: {
>> + struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)ssp1;
>> + struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)ssp2;
>> + if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
>> + return 0;
>> + if (sin1->sin6_port != sin2->sin6_port)
>> + return 0;
>> + break;
>> + }
>> + default:
>> + return 0;
>> + }
>> +
>> + return 1;
>> +}
>> +
>> static int nfs_compare_super(struct super_block *sb, void *data)
>> {
>> struct nfs_sb_mountdata *sb_mntdata = data;
>> struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
>> int mntflags = sb_mntdata->mntflags;
>>
>> - if (memcmp(&old->nfs_client->cl_addr,
>> - &server->nfs_client->cl_addr,
>> - sizeof(old->nfs_client->cl_addr)) != 0)
>> + if (!nfs_compare_super_address(old, server))
>> return 0;
>> /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
>> if (old->flags & NFS_MOUNT_UNSHARED)
>>
>
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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