Ack by me.
On Tue, May 9, 2023 at 12:05 PM Steve French <smfrench@xxxxxxxxx> wrote:
>
> 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 <dhowells@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: 78c09634f7dc ("Cifs: Fix kernel oops caused by deferred close
> for files.")
>
> See attached
> --
> Thanks,
>
> Steve
