ovl: fix missing upper fs freeze protection on copy up for ioctl
commit 3428030da004a1128cbdcf93dc03e16f184d845b upstream. Generalize the helper ovl_open_maybe_copy_up() and use it to copy up file with data before FS_IOC_SETFLAGS ioctl. The FS_IOC_SETFLAGS ioctl is a bit of an odd ball in vfs, which probably caused the confusion. File may be open O_RDONLY, but ioctl modifies the file. VFS does not call mnt_want_write_file() nor lock inode mutex, but fs-specific code for FS_IOC_SETFLAGS does. So ovl_ioctl() calls mnt_want_write_file() for the overlay file, and fs-specific code calls mnt_want_write_file() for upper fs file, but there was no call for ovl_want_write() for copy up duration which prevents overlayfs from copying up on a frozen upper fs. Fixes: dab5ca8f ("ovl: add lsattr/chattr support") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Acked-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing
想要评论请 注册 或 登录