fuse: revalidate: don't invalidate if interrupted

stable inclusion
from stable-v4.19.201
commit 00260209e140aae7f1a274b27e29fa6b4e986f95
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7XMB3
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=00260209e140aae7f1a274b27e29fa6b4e986f95



--------------------------------

commit a9d1c4c6 upstream.

If the LOOKUP request triggered from fuse_dentry_revalidate() is
interrupted, then the dentry will be invalidated, possibly resulting in
submounts being unmounted.

Reported-by: Xu Rongbo <xurongbo@baidu.com>
Closes: https://lore.kernel.org/all/CAJfpegswN_CJJ6C3RZiaK6rpFmNyWmXfaEpnQUJ42KCwNF5tWw@mail.gmail.com/


Fixes: 9e6268db ("[PATCH] FUSE - read-write operations")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>