core: Make support for "stateless stateids" configurable.

Commit c8d57f2 introduced support for stateless stateids.

This may not be desirable, as this breaks the inherent sequence order of
stateids, adding extra requirements for logging/journaling and advanced
VirtualFileSystems. Moreover, this may leave the macOS NFSv4.0 client in
a state where all stateids remain "stateless".

Make support for this feature configurable by adding a flag to
NFSv4StateHandler and move the support logic into NFSv4StateHandler.

Also fix OperationREAD and OperationWRITE to get the NFSv4StateHandler
only once per call from the context.

Signed-off-by: Christian Kohlschütter <christian@kohlschutter.com>

Author: kohlschuetter

core/src/main/java/org/dcache/nfs/v4/NFSv4StateHandler.java

@@ -109,6 +109,8 @@ public class NFSv4StateHandler {
      */
     private final Clock _clock;
 
+    private boolean supportStateless = true;
+
     public NFSv4StateHandler() {
         this(Duration.ofSeconds(NFSv4Defaults.NFS4_LEASE_TIME), 0, new EphemeralClientRecoveryStore());
     }
@@ -500,4 +502,40 @@ public Duration getLeaseTime() {
         return _leaseTime;
     }
 
+    /**
+     * Checks if stateless stateids are supported.
+     * 
+     * @return true if supported.
+     */
+    public boolean isSupportStateless() {
+        return supportStateless;
+    }
+
+    /**
+     * Enables/disables support for stateless stateids.
+     * 
+     * @param supportStateless flag.
+     */
+    public void setSupportStateless(boolean supportStateless) {
+        this.supportStateless = supportStateless;
+    }
+
+    /**
+     * Checks if the given stateid is stateless. If so but stateless stateids are not supported, a
+     * {@link BadStateidException} is thrown.
+     * 
+     * @param stateid The stateid.
+     * @return {@code true} if stateless.
+     * @throws BadStateidException if stateless but not supported.
+     * @see #setSupportStateless(boolean)
+     */
+    public boolean checkStatelessAndSupported(stateid4 stateid) throws BadStateidException {
+        if (Stateids.isStateLess(stateid)) {
+            if (supportStateless) {
+                return true;
+            }
+            throw new BadStateidException();
+        }
+        return false;
+    }
 }

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

@@ -49,7 +49,9 @@ public void process(CompoundContext context, nfs_resop4 result) throws IOExcepti
 
         stateid4 stateid = Stateids.getCurrentStateidIfNeeded(context, _args.opread.stateid);
         var inode = context.currentInode();
-        if (Stateids.isStateLess(stateid)) {
+
+        NFSv4StateHandler stateHandler = context.getStateHandler();
+        if (stateHandler.checkStatelessAndSupported(stateid)) {
             // Anonymous access as per RFC 7530
             // https://datatracker.ietf.org/doc/html/rfc7530#section-9.1.4.3
             // we only check file access rights.
@@ -64,13 +66,13 @@ public void process(CompoundContext context, nfs_resop4 result) throws IOExcepti
                  *
                  * With introduction of sessions in v4.1 update of the lease time done through SEQUENCE operations.
                  */
-                context.getStateHandler().updateClientLeaseTime(stateid);
-                client = context.getStateHandler().getClientIdByStateId(stateid);
+                stateHandler.updateClientLeaseTime(stateid);
+                client = stateHandler.getClientIdByStateId(stateid);
             } else {
                 client = context.getSession().getClient();
             }
 
-            int shareAccess = context.getStateHandler().getFileTracker().getShareAccess(client, inode, stateid);
+            int shareAccess = stateHandler.getFileTracker().getShareAccess(client, inode, stateid);
             if ((shareAccess & nfs4_prot.OPEN4_SHARE_ACCESS_READ) == 0) {
                 throw new OpenModeException("Invalid open mode");
             }

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

@@ -68,7 +68,8 @@ public void process(CompoundContext context, nfs_resop4 result) throws ChimeraNF
         }
 
         var inode = context.currentInode();
-        if (Stateids.isStateLess(stateid)) {
+        NFSv4StateHandler stateHandler = context.getStateHandler();
+        if (stateHandler.checkStatelessAndSupported(stateid)) {
             // Anonymous access as per RFC 7530
             // https://datatracker.ietf.org/doc/html/rfc7530#section-9.1.4.3
             // we only check file access rights.
@@ -85,13 +86,13 @@ public void process(CompoundContext context, nfs_resop4 result) throws ChimeraNF
                  *
                  * With introduction of sessions in v4.1 update of the lease time done through SEQUENCE operations.
                  */
-                context.getStateHandler().updateClientLeaseTime(stateid);
-                client = context.getStateHandler().getClientIdByStateId(stateid);
+                stateHandler.updateClientLeaseTime(stateid);
+                client = stateHandler.getClientIdByStateId(stateid);
             } else {
                 client = context.getSession().getClient();
             }
 
-            int shareAccess = context.getStateHandler().getFileTracker().getShareAccess(client, inode, stateid);
+            int shareAccess = stateHandler.getFileTracker().getShareAccess(client, inode, stateid);
             if ((shareAccess & nfs4_prot.OPEN4_SHARE_ACCESS_WRITE) == 0) {
                 throw new OpenModeException("Invalid open mode");
             }