not overwriting file_lock structure after GET_LK

If we have preventing lock, cifs should overwrite file_lock structure
with info about preventing lock. If we haven't preventing lock, cifs
should leave it unchanged except for the lock type (change it to F_UNLCK).

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 26 insertions, 2 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ca2ba7a0193c..d9e86504b9d4 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -838,8 +838,32 @@ 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);