[PATCH] knfsd: add some new fsid types

Add support for using a filesystem UUID to identify and export point in the
filehandle.

For NFSv2, this UUID is xor-ed down to 4 or 8 bytes so that it doesn't take up
too much room.  For NFSv3+, we use the full 16 bytes, and possibly also a
64bit inode number for exports beneath the root of a filesystem.

When generating an fsid to return in 'stat' information, use the UUID (hashed
down to size) if it is available and a small 'fsid' was not specifically
provided.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/include/linux/nfsd/export.h b/include/linux/nfsd/export.h
index 045e38cdbe64..9f62d6182d32 100644
--- a/include/linux/nfsd/export.h
+++ b/include/linux/nfsd/export.h
@@ -74,19 +74,20 @@ struct svc_export {
 	uid_t			ex_anon_uid;
 	gid_t			ex_anon_gid;
 	int			ex_fsid;
+	unsigned char *		ex_uuid; /* 16 byte fsid */
 	struct nfsd4_fs_locations ex_fslocs;
 };
 
 /* an "export key" (expkey) maps a filehandlefragement to an
- * svc_export for a given client.  There can be two per export, one
- * for type 0 (dev/ino), one for type 1 (fsid)
+ * svc_export for a given client.  There can be several per export,
+ * for the different fsid types.
  */
 struct svc_expkey {
 	struct cache_head	h;
 
 	struct auth_domain *	ek_client;
 	int			ek_fsidtype;
-	u32			ek_fsid[3];
+	u32			ek_fsid[6];
 
 	struct vfsmount *	ek_mnt;
 	struct dentry *		ek_dentry;