1 files changed, 18 insertions, 3 deletions

diff --git a/sys/fs/msdosfs/msdosfs_lookup.c b/sys/fs/msdosfs/msdosfs_lookup.c
index 14920981790a1..446f0b214275c 100644
--- a/sys/fs/msdosfs/msdosfs_lookup.c
+++ b/sys/fs/msdosfs/msdosfs_lookup.c
@@ -114,7 +114,7 @@ msdosfs_lookup(ap)
 	int unlen;
 
 	int wincnt = 1;
-	int chksum = -1;
+	int chksum = -1, chksum_ok;
 	int olddos = 1;
 	cnp->cn_flags &= ~PDIRUNLOCK;
 
@@ -283,7 +283,8 @@ msdosfs_lookup(ap)
 				/*
 				 * Check for a checksum or name match
 				 */
-				if (chksum != winChksum(dep->deName)
+				chksum_ok = (chksum == winChksum(dep->deName));
+				if (!chksum_ok
 				    && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
 					chksum = -1;
 					continue;
@@ -298,7 +299,21 @@ msdosfs_lookup(ap)
 				 * this lookup.
 				 */
 				dp->de_fndoffset = diroff;
-				dp->de_fndcnt = wincnt - 1;
+				if (chksum_ok && nameiop == RENAME) {
+					/*
+					 * Target had correct long name
+					 * directory entries, reuse them
+					 * as needed.
+					 */
+					dp->de_fndcnt = wincnt - 1;
+				} else {
+					/*
+					 * Long name directory entries
+					 * not present or corrupt, can only
+					 * reuse dos directory entry.
+					 */
+					dp->de_fndcnt = 0;
+				}
 
 				goto found;
 			}