[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, 8 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 18aa9440df14..0efba557fb55 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1563,14 +1563,20 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
                 if (exp->ex_fslocs.migrated) {
                         WRITE64(NFS4_REFERRAL_FSID_MAJOR);
                         WRITE64(NFS4_REFERRAL_FSID_MINOR);
-                } else if (is_fsid(fhp, rqstp->rq_reffh)) {
+                } else switch(fsid_source(fhp)) {
+                case FSIDSOURCE_FSID:
                         WRITE64((u64)exp->ex_fsid);
                         WRITE64((u64)0);
-                } else {
+                        break;
+                case FSIDSOURCE_DEV:
                         WRITE32(0);
                         WRITE32(MAJOR(stat.dev));
                         WRITE32(0);
                         WRITE32(MINOR(stat.dev));
+                        break;
+                case FSIDSOURCE_UUID:
+                        WRITEMEM(exp->ex_uuid, 16);
+                        break;
                 }
         }
         if (bmval0 & FATTR4_WORD0_UNIQUE_HANDLES) {