SMB3: drop reference to cfile before sending oplock break

In cifs_oplock_break function we drop reference to a cfile at
the end of function, due to which close command goes on wire
after lease break acknowledgment even if file is already closed
by application but we had deferred the handle close.
If other client with limited file shareaccess waiting on lease
break ack proceeds operation on that file as soon as first client
sends ack, then we may encounter status sharing violation error
because of open handle.
Solution is to put reference to cfile(send close on wire if last ref)
and then send oplock acknowledgment to server.

Fixes: 9e31678 ("SMB3: fix lease break timeout when multiple deferred close handles for the same file.")
Cc: stable@kernel.org
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: bharathsm-ms

fs/cifs/cifsglob.h

@@ -424,8 +424,8 @@ struct smb_version_operations {
 	/* check for STATUS_NETWORK_SESSION_EXPIRED */
 	bool (*is_session_expired)(char *);
 	/* send oplock break response */
-	int (*oplock_response)(struct cifs_tcon *, struct cifs_fid *,
-			       struct cifsInodeInfo *);
+	int (*oplock_response)(struct cifs_tcon *tcon, __u64 persistent_fid, __u64 volatile_fid,
+			__u16 net_fid, struct cifsInodeInfo *cifs_inode);
 	/* query remote filesystem */
 	int (*queryfs)(const unsigned int, struct cifs_tcon *,
 		       struct cifs_sb_info *, struct kstatfs *);

fs/cifs/file.c

@@ -4881,7 +4881,9 @@ void cifs_oplock_break(struct work_struct *work)
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	struct TCP_Server_Info *server = tcon->ses->server;
 	int rc = 0;
-	bool purge_cache = false;
+	bool purge_cache = false, oplock_break_cancelled;
+	__u64 persistent_fid, volatile_fid;
+	__u16 net_fid;
 
 	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
 			TASK_UNINTERRUPTIBLE);
@@ -4926,19 +4928,24 @@ void cifs_oplock_break(struct work_struct *work)
 	if (!CIFS_CACHE_HANDLE(cinode) && !list_empty(&cinode->deferred_closes))
 		cifs_close_deferred_file(cinode);
 
+	persistent_fid = cfile->fid.persistent_fid;
+	volatile_fid = cfile->fid.volatile_fid;
+	net_fid = cfile->fid.netfid;
+	oplock_break_cancelled = cfile->oplock_break_cancelled;
+
+	_cifsFileInfo_put(cfile, false /* do not wait for ourself */, false);
 	/*
 	 * releasing stale oplock after recent reconnect of smb session using
 	 * a now incorrect file handle is not a data integrity issue but do
 	 * not bother sending an oplock release if session to server still is
 	 * disconnected since oplock already released by the server
 	 */
-	if (!cfile->oplock_break_cancelled) {
-		rc = tcon->ses->server->ops->oplock_response(tcon, &cfile->fid,
-							     cinode);
+	if (!oplock_break_cancelled) {
+		rc = tcon->ses->server->ops->oplock_response(tcon, persistent_fid,
+				volatile_fid, net_fid, cinode);
 		cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
 	}
 
-	_cifsFileInfo_put(cfile, false /* do not wait for ourself */, false);
 	cifs_done_oplock_break(cinode);
 }
 

fs/cifs/smb1ops.c

@@ -897,12 +897,11 @@ cifs_close_dir(const unsigned int xid, struct cifs_tcon *tcon,
 }
 
 static int
-cifs_oplock_response(struct cifs_tcon *tcon, struct cifs_fid *fid,
-		     struct cifsInodeInfo *cinode)
+cifs_oplock_response(struct cifs_tcon *tcon, __u64 persistent_fid,
+		__u64 volatile_fid, __u16 net_fid, struct cifsInodeInfo *cinode)
 {
-	return CIFSSMBLock(0, tcon, fid->netfid, current->tgid, 0, 0, 0, 0,
-			   LOCKING_ANDX_OPLOCK_RELEASE, false,
-			   CIFS_CACHE_READ(cinode) ? 1 : 0);
+	return CIFSSMBLock(0, tcon, net_fid, current->tgid, 0, 0, 0, 0,
+			   LOCKING_ANDX_OPLOCK_RELEASE, false, CIFS_CACHE_READ(cinode) ? 1 : 0);
 }
 
 static int

fs/cifs/smb2ops.c

@@ -2383,15 +2383,14 @@ smb2_is_network_name_deleted(char *buf, struct TCP_Server_Info *server)
 }
 
 static int
-smb2_oplock_response(struct cifs_tcon *tcon, struct cifs_fid *fid,
-		     struct cifsInodeInfo *cinode)
+smb2_oplock_response(struct cifs_tcon *tcon, __u64 persistent_fid,
+		__u64 volatile_fid, __u16 net_fid, struct cifsInodeInfo *cinode)
 {
 	if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
 		return SMB2_lease_break(0, tcon, cinode->lease_key,
 					smb2_get_lease_state(cinode));
 
-	return SMB2_oplock_break(0, tcon, fid->persistent_fid,
-				 fid->volatile_fid,
+	return SMB2_oplock_break(0, tcon, persistent_fid, volatile_fid,
 				 CIFS_CACHE_READ(cinode) ? 1 : 0);
 }