Re: [libvirt] [PATCH 6/8] qemuDomainCreateDeviceRecursive: Support file mount points

https://bugzilla.redhat.com/show_bug.cgi?id=1462060 When building a qemu namespace we might be dealing with bare regular files. Files that live under /dev. For instance /dev/my_awesome_disk: <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/dev/my_awesome_disk'/> <target dev='vdc' bus='virtio'/> </disk> # qemu-img create -f qcow2 /dev/my_awesome_disk 10M So far we were mknod()-ing them which is obviously wrong. We need to touch the file and bind mount it to the original: 1) touch /var/run/libvirt/qemu/fedora.dev/my_awesome_disk 2) mount --bind /dev/my_awesome_disk /var/run/libvirt/qemu/fedora.dev/my_awesome_disk Later, when the new /dev is built and replaces original /dev the file is going to live at expected location. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_domain.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 977b5c089..6d7c218a2 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -7708,6 +7708,7 @@ qemuDomainCreateDeviceRecursive(const char *device, int ret = -1; bool isLink = false; bool isDev = false; + bool isReg = false; bool create = false; #ifdef WITH_SELINUX char *tcon = NULL; @@ -7731,6 +7732,7 @@ qemuDomainCreateDeviceRecursive(const char *device, isLink = S_ISLNK(sb.st_mode); isDev = S_ISCHR(sb.st_mode) || S_ISBLK(sb.st_mode); + isReg = S_ISREG(sb.st_mode); /* Here, @device might be whatever path in the system. We * should create the path in the namespace iff it's "/dev" @@ -7842,16 +7844,12 @@ qemuDomainCreateDeviceRecursive(const char *device, } goto cleanup; } - - /* Set the file permissions again: mknod() is affected by the - * current umask, and as such might not have set them correctly */ + } else if (isReg) { if (create && - chmod(devicePath, sb.st_mode) < 0) { - virReportSystemError(errno, - _("Failed to set permissions for device %s"), - devicePath); + virFileTouch(devicePath, sb.st_mode) < 0) goto cleanup; - } + /* Just create the file here so that code below sets + * proper owner and mode. Bind mount only after that. */ } else { virReportError(VIR_ERR_OPERATION_UNSUPPORTED, _("unsupported device type %s %o"), @@ -7871,6 +7869,15 @@ qemuDomainCreateDeviceRecursive(const char *device, goto cleanup; }

+ /* Symlinks don't have mode */ + if (!isLink &&

+ chmod(devicePath, sb.st_mode) < 0) { + virReportSystemError(errno, + _("Failed to set permissions for device %s"),

+ devicePath); + goto cleanup; + } + /* Symlinks don't have ACLs. */ if (!isLink && virFileCopyACLs(device, devicePath) < 0 && @@ -7903,6 +7910,11 @@ qemuDomainCreateDeviceRecursive(const char *device, } #endif + /* Finish mount process started earlier. */ + if (isReg && + virFileBindMountDevice(device, devicePath) < 0) + goto cleanup; + ret = 0; cleanup: VIR_FREE(target);