From 6d103a57652216bdad66203511f7f97008e22bac Mon Sep 17 00:00:00 2001 From: Steve French Date: Tue, 9 May 2023 01:00:42 -0500 Subject: [PATCH] SMB3: force unmount was failing to close deferred close files commit 2cb6f968775a9fd60c90a6042b9550bcec3ea087 upstream. In investigating a failure with xfstest generic/392 it was noticed that mounts were reusing a superblock that should already have been freed. This turned out to be related to deferred close files keeping a reference count until the closetimeo expired. Currently the only way an fs knows that mount is beginning is when force unmount is called, but when this, ie umount_begin(), is called all deferred close files on the share (tree connection) should be closed immediately (unless shared by another mount) to avoid using excess resources on the server and to avoid reusing a superblock which should already be freed. In umount_begin, close all deferred close handles for that share if this is the last mount using that share on this client (ie send the SMB3 close request over the wire for those that have been already closed by the app but that we have kept a handle lease open for and have not sent closes to the server for yet). Reported-by: David Howells Acked-by: Bharath SM Cc: Fixes: 78c09634f7dc ("Cifs: Fix kernel oops caused by deferred close for files.") Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/cifsfs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 6dff4826f9fd..078df1e2dd18 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -743,6 +743,7 @@ static void cifs_umount_begin(struct super_block *sb) spin_unlock(&tcon->tc_lock); spin_unlock(&cifs_tcp_ses_lock); + cifs_close_all_deferred_files(tcon); /* cancel_brl_requests(tcon); */ /* BB mark all brl mids as exiting */ /* cancel_notify_requests(tcon); */ if (tcon->ses && tcon->ses->server) {