Am 13.08.2018 um 04:39 hat Fam Zheng geschrieben: > If we know we've already locked the bytes, don't do it again; similarly > don't unlock a byte if we haven't locked it. This doesn't change the > behavior, but fixes a corner case explained below. > > Libvirt had an error handling bug that an image can get its (ownership, > file mode, SELinux) permissions changed (RHBZ 1584982) by mistake behind > QEMU. Specifically, an image in use by Libvirt VM has: > > $ ls -lhZ b.img > -rw-r--r--. qemu qemu system_u:object_r:svirt_image_t:s0:c600,c690 b.img > > Trying to attach it a second time won't work because of image locking. > And after the error, it becomes: > > $ ls -lhZ b.img > -rw-r--r--. root root system_u:object_r:virt_image_t:s0 b.img > > Then, we won't be able to do OFD lock operations with the existing fd. > In other words, the code such as in blk_detach_dev: > > blk_set_perm(blk, 0, BLK_PERM_ALL, &error_abort); > > can abort() QEMU, out of environmental changes. > > This patch is an easy fix to this and the change is regardlessly > reasonable, so do it. > > Signed-off-by: Fam Zheng <[email protected]>
Thanks, applied to the block branch. Kevin
