Re: [Libguestfs] [Qemu-block] [PATCH] tests: regressions: make test-big-heap use a temporary empty file

On Wednesday, 21 March 2018 14:45:38 CET Eric Blake wrote: > [adding qemu lists] > > On 03/21/2018 07:51 AM, Richard W.M. Jones wrote: > > On Wed, Mar 21, 2018 at 01:44:17PM +0100, Pino Toscano wrote: > >> Newer versions of qemu use file locking for the images by default, and > >> apparently that does not work with /dev/null. Since this test just > >> calls qemu-img to get the format of an empty image, create a temporary > >> one instead. > > > > ACK, but feels like this is a bug in qemu-img to me. > > You're right that file locking on a character device like /dev/null is > not going to work as expected, but is it a case where fcntl() actually > fails, or is it worse where the fcntl() claiming the locks "succeeds" > but doesn't do what we want? That is, what were the actual error > messages you ran into? $ qemu-img --version qemu-img version 2.10.1(qemu-2.10.1-2.fc27) Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers $ qemu-img info /dev/null qemu-img: Could not open '/dev/null': Failed to get "consistent read" lock Is another process using the image?