From 0959ea990751b6604d0f65ca1f3c19621259b859 Mon Sep 17 00:00:00 2001
From: cha0smaster <cha0smaster>
Date: Wed, 3 Aug 2005 21:25:42 +0000
Subject: [PATCH] Fix ntfs_is_cb_compressed for nasty runlist merging case in
 which compression block was incorrectly treated as not compressed.

---
 ChangeLog          |  2 ++
 libntfs/compress.c | 11 ++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index e7da835c..6290a151 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -25,6 +25,8 @@ xx/xx/xxxx - 1.12.0-WIP
 	- Make find work correctly on volumes mounted by ntfsmount.  (Yura)
 	- Replaced all occurances of ENOTSUP to EOPNOTSUPP to be in better
 	  harmony with the kernel driver.  (Szaka)
+	- Fix ntfs_is_cb_compressed for nasty runlist merging case in which
+	  compression block was incorrectly treated as not compressed.  (Yura)
 
 20/07/2005 - 1.11.1 - Fix several ntfsmount bugs.
 
diff --git a/libntfs/compress.c b/libntfs/compress.c
index 407d4d90..f0cb164c 100644
--- a/libntfs/compress.c
+++ b/libntfs/compress.c
@@ -3,6 +3,7 @@
  *		project.
  *
  * Copyright (c) 2004-2005 Anton Altaparmakov
+ * Copyright (c)      2005 Yura Pakhuchiy
  *
  * This program/include file is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as published
@@ -265,9 +266,17 @@ static __inline__ BOOL ntfs_is_cb_compressed(ntfs_attr *na,
 		rl++;
 		/* Map the next runlist fragment if it is not mapped. */
 		if (rl->lcn < LCN_HOLE || !rl->length) {
-			rl = ntfs_attr_find_vcn(na, rl->vcn);
+			VCN tvcn;
+
+			tvcn = rl->vcn;
+			rl = ntfs_attr_find_vcn(na, tvcn);
 			if (!rl || rl->lcn < LCN_HOLE || !rl->length)
 				return TRUE;
+			if (rl->vcn < tvcn) {
+				/* Runs merged. Need special handling. */
+				cb_clusters -= rl->length - (tvcn - rl->vcn);
+				continue;
+			}
 		}
 		/* If the current run is sparse, the cb is compressed. */
 		if (rl->lcn == LCN_HOLE)