NFS: Store the file system "fsid" value in the NFS super block.

This should enable us to detect if we are crossing a mountpoint in the
case where the server is exporting "nohide" mounts.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/nfs_fs.h

@@ -16,8 +16,6 @@
 #include <linux/rwsem.h>
 #include <linux/wait.h>
 
-#include <linux/nfs_fs_sb.h>
-
 #include <linux/sunrpc/debug.h>
 #include <linux/sunrpc/auth.h>
 #include <linux/sunrpc/clnt.h>
@@ -27,6 +25,9 @@
 #include <linux/nfs3.h>
 #include <linux/nfs4.h>
 #include <linux/nfs_xdr.h>
+
+#include <linux/nfs_fs_sb.h>
+
 #include <linux/rwsem.h>
 #include <linux/mempool.h>
 

include/linux/nfs_fs_sb.h

@@ -35,6 +35,7 @@ struct nfs_server {
 	char *			hostname;	/* remote hostname */
 	struct nfs_fh		fh;
 	struct sockaddr_in	addr;
+	struct nfs_fsid		fsid;
 	unsigned long		mount_time;	/* when this fs was mounted */
 #ifdef CONFIG_NFS_V4
 	/* Our own IP address, as a null-terminated string.

include/linux/nfs_page.h

@@ -13,7 +13,6 @@
 #include <linux/list.h>
 #include <linux/pagemap.h>
 #include <linux/wait.h>
-#include <linux/nfs_fs_sb.h>
 #include <linux/sunrpc/auth.h>
 #include <linux/nfs_xdr.h>
 

include/linux/nfs_xdr.h

@@ -14,11 +14,19 @@
 #define NFS_DEF_FILE_IO_SIZE	(4096U)
 #define NFS_MIN_FILE_IO_SIZE	(1024U)
 
-struct nfs4_fsid {
-	__u64 major;
-	__u64 minor;
+struct nfs_fsid {
+	uint64_t		major;
+	uint64_t		minor;
 };
 
+/*
+ * Helper for checking equality between 2 fsids.
+ */
+static inline int nfs_fsid_equal(const struct nfs_fsid *a, const struct nfs_fsid *b)
+{
+	return a->major == b->major && a->minor == b->minor;
+}
+
 struct nfs_fattr {
 	unsigned short		valid;		/* which fields are valid */
 	__u64			pre_size;	/* pre_op_attr.size	  */
@@ -40,10 +48,7 @@ struct nfs_fattr {
 		} nfs3;
 	} du;
 	dev_t			rdev;
-	union {
-		__u64		nfs3;		/* also nfs2 */
-		struct nfs4_fsid nfs4;
-	} fsid_u;
+	struct nfs_fsid		fsid;
 	__u64			fileid;
 	struct timespec		atime;
 	struct timespec		mtime;