core: Allow Stat to not contain 64-bit "Ino" inode values

VirtualFileSystems must currently return a 64-bit "Ino" value that is
used as the NFS "fileid" (through Stat.setIno, called via
getAttr(Inode)).

In the NFSv4 spec, that 64-bit "fileid" is a "recommended" (not
"required") field.

Allow for the absence of this "Ino" value, so file systems that only
refer to their entries via NFSv4 file handles don't have invent some
non-stable number.

Note that this value is indeed required for NFSv3 compatibility, so any
file system choosing to not call Stat.setIno will likely fail to run on
NFSv3.

Related: #149
Signed-off-by: Christian Kohlschütter <[email protected]>

Author: kohlschuetter

core/src/main/java/org/dcache/nfs/v4/OperationGETATTR.java

@@ -66,7 +66,6 @@
 import org.dcache.nfs.v4.xdr.fattr4_numlinks;
 import org.dcache.nfs.v4.xdr.fattr4_owner;
 import org.dcache.nfs.v4.xdr.fattr4_rawdev;
-import org.dcache.nfs.v4.xdr.fattr4_rdattr_error;
 import org.dcache.nfs.v4.xdr.fattr4_size;
 import org.dcache.nfs.v4.xdr.fattr4_space_avail;
 import org.dcache.nfs.v4.xdr.fattr4_space_free;
@@ -256,7 +255,11 @@ static Optional<? extends XdrAble> fattr2xdr(int fattr, VirtualFileSystem fs, In
             case nfs4_prot.FATTR4_CHOWN_RESTRICTED:
                 return Optional.empty();
             case nfs4_prot.FATTR4_FILEID:
-                return Optional.of(new fattr4_fileid(stat.getIno()));
+                if (stat.hasIno()) {
+                    return Optional.of(new fattr4_fileid(stat.getIno()));
+                } else {
+                    return Optional.empty();
+                }
             case nfs4_prot.FATTR4_FILES_AVAIL:
                 fsStat = getFsStat(fsStat, fs);
                 fattr4_files_avail files_avail = new fattr4_files_avail(fsStat.getTotalFiles() - fsStat.getUsedFiles());
@@ -351,6 +354,9 @@ static Optional<? extends XdrAble> fattr2xdr(int fattr, VirtualFileSystem fs, In
                  * TODO!!!:
                  */
 
+                if (!stat.hasIno()) {
+                    return Optional.empty();
+                }
                 long mofi = stat.getIno();
 
                 if (mofi == 0x00b0a23a /* it's a root */) {

core/src/main/java/org/dcache/nfs/vfs/Stat.java

@@ -153,6 +153,15 @@ public void setDev(int dev) {
         _dev = dev;
     }
 
+    /**
+     * Checks if an inode number has been set (even if 0).
+     *
+     * @return {@code true} if set.
+     */
+    public boolean hasIno() {
+        return isDefined(StatAttribute.INO);
+    }
+
     /**
      * Returns file inode number.
      */

core/src/test/java/org/dcache/nfs/vfs/StatTest.java

@@ -168,7 +168,9 @@ public void testNotDefinedGetBtime() {
     @Test
     public void testGetIno() {
         Stat stat = new Stat();
+        assertFalse(stat.hasIno());
         stat.setIno(1);
+        assertTrue(stat.hasIno());
         assertEquals(1, stat.getIno());
 
     }