[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, 23 insertions, 8 deletions

diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index e695660921e..6f677988c71 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -149,6 +149,27 @@ decode_sattr3(__be32 *p, struct iattr *iap)
         return p;
 }
 
+static __be32 *encode_fsid(__be32 *p, struct svc_fh *fhp)
+{
+        u64 f;
+        switch(fsid_source(fhp)) {
+        default:
+        case FSIDSOURCE_DEV:
+                p = xdr_encode_hyper(p, (u64)huge_encode_dev
+                                     (fhp->fh_dentry->d_inode->i_sb->s_dev));
+                break;
+        case FSIDSOURCE_FSID:
+                p = xdr_encode_hyper(p, (u64) fhp->fh_export->ex_fsid);
+                break;
+        case FSIDSOURCE_UUID:
+                f = ((u64*)fhp->fh_export->ex_uuid)[0];
+                f ^= ((u64*)fhp->fh_export->ex_uuid)[1];
+                p = xdr_encode_hyper(p, f);
+                break;
+        }
+        return p;
+}
+
 static __be32 *
 encode_fattr3(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
               struct kstat *stat)
@@ -169,10 +190,7 @@ encode_fattr3(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
         p = xdr_encode_hyper(p, ((u64)stat->blocks) << 9);
         *p++ = htonl((u32) MAJOR(stat->rdev));
         *p++ = htonl((u32) MINOR(stat->rdev));
-        if (is_fsid(fhp, rqstp->rq_reffh))
-                p = xdr_encode_hyper(p, (u64) fhp->fh_export->ex_fsid);
-        else
-                p = xdr_encode_hyper(p, (u64) huge_encode_dev(stat->dev));
+        p = encode_fsid(p, fhp);
         p = xdr_encode_hyper(p, (u64) stat->ino);
         p = encode_time3(p, &stat->atime);
         lease_get_mtime(dentry->d_inode, &time); 
@@ -203,10 +221,7 @@ encode_saved_post_attr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)
         p = xdr_encode_hyper(p, ((u64)fhp->fh_post_blocks) << 9);
         *p++ = fhp->fh_post_rdev[0];
         *p++ = fhp->fh_post_rdev[1];
-        if (is_fsid(fhp, rqstp->rq_reffh))
-                p = xdr_encode_hyper(p, (u64) fhp->fh_export->ex_fsid);
-        else
-                p = xdr_encode_hyper(p, (u64)huge_encode_dev(inode->i_sb->s_dev));
+        p = encode_fsid(p, fhp);
         p = xdr_encode_hyper(p, (u64) inode->i_ino);
         p = encode_time3(p, &fhp->fh_post_atime);
         p = encode_time3(p, &fhp->fh_post_mtime);