1 files changed, 27 insertions, 2 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ca2ba7a0193c..9b11a8f56f3a 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -31,6 +31,7 @@
 #include <linux/task_io_accounting_ops.h>
 #include <linux/delay.h>
 #include <linux/mount.h>
+#include <linux/slab.h>
 #include <asm/div64.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
@@ -838,8 +839,32 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 
                 } else {
                         /* if rc == ERR_SHARING_VIOLATION ? */
-                        rc = 0; /* do not change lock type to unlock
-                                   since range in use */
+                        rc = 0;
+
+                        if (lockType & LOCKING_ANDX_SHARED_LOCK) {
+                                pfLock->fl_type = F_WRLCK;
+                        } else {
+                                rc = CIFSSMBLock(xid, tcon, netfid, length,
+                                        pfLock->fl_start, 0, 1,
+                                        lockType | LOCKING_ANDX_SHARED_LOCK,
+                                        0 /* wait flag */);
+                                if (rc == 0) {
+                                        rc = CIFSSMBLock(xid, tcon, netfid,
+                                                length, pfLock->fl_start, 1, 0,
+                                                lockType |
+                                                LOCKING_ANDX_SHARED_LOCK,
+                                                0 /* wait flag */);
+                                        pfLock->fl_type = F_RDLCK;
+                                        if (rc != 0)
+                                                cERROR(1, ("Error unlocking "
+                                                "previously locked range %d "
+                                                "during test of lock", rc));
+                                        rc = 0;
+                                } else {
+                                        pfLock->fl_type = F_WRLCK;
+                                        rc = 0;
+                                }
+                        }
                 }
 
                 FreeXid(xid);