Date: Thu, 26 Oct 2006 11:14:13 -0400
From: Steve Dickson <SteveD@redhat.com>
Subject: [RHEL5] [PATCH] NFSv4: fs_locations support

A month after RHEL5 was branched from upstream,
patches were submitted and commit to the mainstream
kernel that introduce File System Replication and
Migration support for NFS version 4.

File System Replication and Migration is a feature
in V4 that allows server to tell clients that the
file (or file system) they are asking has just
moved to another server. Such a feature will help
with load balancing and/or resource relocation.

This is something I'm pretty confident our competitors
will have in upcoming releases, so we really need a
way to get this in RHEL5.

Being that its so late in the release cycle, adding
the entire feature may not make sense. So I'm proposing
that we only added the kABI footprint which will allow us
to added the feature in an update release as well as let
the code "bake" a bit longer in upstream.

So the attached patch only has the header file changes.

The entire patch can be found at:
http://people.redhat.com/steved/bz212352/linux-2.6.18-nfs4-fsloc.patch

The upstream patch series can be found in:
http://people.redhat.com/steved/bz212352/

The bz is:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=212352

steved.


--- linux-2.6.18.i686/include/linux/nfsd/nfsd.h.orig	2006-10-24 14:12:17.000000000 -0400
+++ linux-2.6.18.i686/include/linux/nfsd/nfsd.h	2006-10-24 15:29:51.000000000 -0400
@@ -210,6 +210,7 @@ void		nfsd_lockd_shutdown(void);
 #define	nfserr_clid_inuse	__constant_htonl(NFSERR_CLID_INUSE)
 #define	nfserr_stale_clientid	__constant_htonl(NFSERR_STALE_CLIENTID)
 #define	nfserr_resource		__constant_htonl(NFSERR_RESOURCE)
+#define	nfserr_moved		__constant_htonl(NFSERR_MOVED)
 #define	nfserr_nofilehandle	__constant_htonl(NFSERR_NOFILEHANDLE)
 #define	nfserr_minor_vers_mismatch	__constant_htonl(NFSERR_MINOR_VERS_MISMATCH)
 #define nfserr_share_denied	__constant_htonl(NFSERR_SHARE_DENIED)
@@ -286,7 +287,6 @@ static inline int is_fsid(struct svc_fh 
 /*
  * The following attributes are currently not supported by the NFSv4 server:
  *    ARCHIVE       (deprecated anyway)
- *    FS_LOCATIONS  (will be supported eventually)
  *    HIDDEN        (unlikely to be supported any time soon)
  *    MIMETYPE      (unlikely to be supported any time soon)
  *    QUOTA_*       (will be supported in a forthcoming patch)
@@ -302,7 +302,7 @@ static inline int is_fsid(struct svc_fh 
  | FATTR4_WORD0_ACLSUPPORT      | FATTR4_WORD0_CANSETTIME   | FATTR4_WORD0_CASE_INSENSITIVE \
  | FATTR4_WORD0_CASE_PRESERVING | FATTR4_WORD0_CHOWN_RESTRICTED                             \
  | FATTR4_WORD0_FILEHANDLE      | FATTR4_WORD0_FILEID       | FATTR4_WORD0_FILES_AVAIL      \
- | FATTR4_WORD0_FILES_FREE      | FATTR4_WORD0_FILES_TOTAL  | FATTR4_WORD0_HOMOGENEOUS      \
+ | FATTR4_WORD0_FILES_FREE      | FATTR4_WORD0_FILES_TOTAL  | FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_HOMOGENEOUS      \
  | FATTR4_WORD0_MAXFILESIZE     | FATTR4_WORD0_MAXLINK      | FATTR4_WORD0_MAXNAME          \
  | FATTR4_WORD0_MAXREAD         | FATTR4_WORD0_MAXWRITE     | FATTR4_WORD0_ACL)
 
--- linux-2.6.18.i686/include/linux/nfsd/export.h.orig	2006-10-24 14:12:17.000000000 -0400
+++ linux-2.6.18.i686/include/linux/nfsd/export.h	2006-10-24 15:31:13.000000000 -0400
@@ -45,15 +45,36 @@
 
 #ifdef __KERNEL__
 
+/*
+ * FS Locations
+ */
+
+#define MAX_FS_LOCATIONS	128
+
+struct nfsd4_fs_location {
+	char *hosts; /* colon separated list of hosts */
+	char *path;  /* slash separated list of path components */
+};
+
+struct nfsd4_fs_locations {
+	uint32_t locations_count;
+	struct nfsd4_fs_location *locations;
+/* If we're not actually serving this data ourselves (only providing a
+ * list of replicas that do serve it) then we set "migrated": */
+	int migrated;
+};
+
 struct svc_export {
 	struct cache_head	h;
 	struct auth_domain *	ex_client;
 	int			ex_flags;
 	struct vfsmount *	ex_mnt;
 	struct dentry *		ex_dentry;
+	char *			ex_path;
 	uid_t			ex_anon_uid;
 	gid_t			ex_anon_gid;
 	int			ex_fsid;
+	struct nfsd4_fs_locations ex_fslocs;
 };
 
 /* an "export key" (expkey) maps a filehandlefragement to an