From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120205220951.546428393@pcw.home.local> Date: Sun, 05 Feb 2012 23:10:38 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Richard Weinberger , Greg KH Subject: [PATCH 49/91] um: fix ubd cow size In-Reply-To: <0635750f5f06ed2ca212b91fcb5c4483@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: 2.6.27-longterm review patch. If anyone has any objections, please let us know. ------------------ commit 8535639810e578960233ad39def3ac2157b0c3ec upstream. ubd_file_size() cannot use ubd_dev->cow.file because at this time ubd_dev->cow.file is not initialized. Therefore, ubd_file_size() will always report a wrong disk size when COW files are used. Reading from /dev/ubd* would crash the kernel. We have to read the correct disk size from the COW file's backing file. Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman --- arch/um/drivers/ubd_kern.c | 31 ++++++++++++++++++++++++++++++- 1 files changed, 30 insertions(+), 1 deletions(-) Index: longterm-2.6.27/arch/um/drivers/ubd_kern.c =================================================================== --- longterm-2.6.27.orig/arch/um/drivers/ubd_kern.c 2012-02-05 22:34:33.536914634 +0100 +++ longterm-2.6.27/arch/um/drivers/ubd_kern.c 2012-02-05 22:34:41.803915498 +0100 @@ -529,8 +529,37 @@ static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) { char *file; + int fd; + int err; - file = ubd_dev->cow.file ? ubd_dev->cow.file : ubd_dev->file; + __u32 version; + __u32 align; + char *backing_file; + time_t mtime; + unsigned long long size; + int sector_size; + int bitmap_offset; + + if (ubd_dev->file && ubd_dev->cow.file) { + file = ubd_dev->cow.file; + + goto out; + } + + fd = os_open_file(ubd_dev->file, global_openflags, 0); + if (fd < 0) + return fd; + + err = read_cow_header(file_reader, &fd, &version, &backing_file, \ + &mtime, &size, §or_size, &align, &bitmap_offset); + os_close_file(fd); + + if(err == -EINVAL) + file = ubd_dev->file; + else + file = backing_file; + +out: return os_file_size(file, size_out); }