[PATCH 04/13] RFC: nfs: change stateid to be a union

Fred Isaman
2010-09-09T18:10:37Z

From: The pNFS Team <linux-nfs@vger.kernel.org>

In NFSv4.1 the stateid consists of the other and seqid fields. For layout
processing we need to numerically compare the seqid value of layout stateids.
To do so, introduce a union to nfs4_stateid to swtich between opaque(16 bytes)
and opaque(12 bytes) / __be32

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Fred Isaman <iisaman@netapp.com>
---
fs/nfs/callback_proc.c | 8 ++++----
include/linux/nfs4.h | 15 +++++++++++++--
2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 930d10f..2950fca 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -118,11 +118,11 @@ int nfs41_validate_delegation_stateid(struct nfs_delegation *delegation, const n
if (delegation == NULL)
return 0;

- /* seqid is 4-bytes long */
- if (((u32 *) &stateid->data)[0] != 0)
+ if (stateid->stateid.seqid != 0)
return 0;
- if (memcmp(&delegation->stateid.data[4], &stateid->data[4],
- sizeof(stateid->data)-4))
+ if (memcmp(&delegation->stateid.stateid.other,
+ &stateid->stateid.other,
+ NFS4_STATEID_OTHER_SIZE))
return 0;

return 1;
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 6798fc3..2dde7c8 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -17,7 +17,9 @@

#define NFS4_BITMAP_SIZE 2
#define NFS4_VERIFIER_SIZE 8
-#define NFS4_STATEID_SIZE 16
+#define NFS4_STATEID_SEQID_SIZE 4
+#define NFS4_STATEID_OTHER_SIZE 12
+#define NFS4_STATEID_SIZE (NFS4_STATEID_SEQID_SIZE + NFS4_STATEID_OTHER_SIZE)
#define NFS4_FHSIZE 128
#define NFS4_MAXPATHLEN PATH_MAX
#define NFS4_MAXNAMLEN NAME_MAX
@@ -167,7 +169,16 @@ struct nfs4_acl {
};

typedef struct { char data[NFS4_VERIFIER_SIZE]; } nfs4_verifier;
-typedef struct { char data[NFS4_STATEID_SIZE]; } nfs4_stateid;
+
+struct nfs41_stateid {
+ __be32 seqid;
+ char other[NFS4_STATEID_OTHER_SIZE];
+} __attribute__ ((packed));
+
+typedef union {
+ char data[NFS4_STATEID_SIZE];
+ struct nfs41_stateid stateid;
+} nfs4_stateid;

enum nfs_opnum4 {
OP_ACCESS = 3,
--
1.7.2.1