On a Wednesday in 2020, Michal Privoznik wrote:
When attaching a device into a domain, the corresponding /dev node might need to be created in the domain's namespace. For some types of files we call mknod(), for symlinks we call symlink(), but for others - which exist in the host namespace - we need to so called 'bind mount' them (which is a way of passing a file/directory between mount namespaces). There is this condition in qemuDomainAttachDeviceMknodRecursive() which decides whether a bind mount will be used, move it into a separate function so that it can be reused later.Signed-off-by: Michal Privoznik <mpriv...@redhat.com> --- src/qemu/qemu_domain_namespace.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_domain_namespace.c b/src/qemu/qemu_domain_namespace.c index 40c4fb36cb..0c40118938 100644 --- a/src/qemu/qemu_domain_namespace.c +++ b/src/qemu/qemu_domain_namespace.c @@ -1253,6 +1253,17 @@ qemuDomainAttachDeviceMknodHelper(pid_t pid G_GNUC_UNUSED, } +static bool +qemuDomainMknodItemIsBindMounted(mode_t st_mode)
To me, IsBindMounted reads like it's done already, but we yet have to do that. Consider: qemuNamespaceMknodItemNeedsBindMount
+{
+ /* A block device S_ISBLK() or a chardev S_ISCHR() is intentionally not
+ * handled. We want to mknod() it instead of passing in through bind
+ * mounting. */
+ return S_ISREG(st_mode) || S_ISFIFO(st_mode) ||
+ S_ISSOCK(st_mode) || S_ISDIR(st_mode);
+}
+
+
static int
qemuDomainAttachDeviceMknodRecursive(virQEMUDriverPtr driver,
virDomainObjPtr vm,
@@ -1267,7 +1278,6 @@ qemuDomainAttachDeviceMknodRecursive(virQEMUDriverPtr
driver,
g_autofree char *target = NULL;
bool isLink;
bool isReg;
- bool isDir;
if (!ttl) {
virReportSystemError(ELOOP,
@@ -1289,10 +1299,9 @@ qemuDomainAttachDeviceMknodRecursive(virQEMUDriverPtr
driver,
}
isLink = S_ISLNK(data.sb.st_mode);
- isReg = S_ISREG(data.sb.st_mode) || S_ISFIFO(data.sb.st_mode) ||
S_ISSOCK(data.sb.st_mode);
- isDir = S_ISDIR(data.sb.st_mode);
+ isReg = qemuDomainMknodItemIsBindMounted(data.sb.st_mode);
note that the variable is still misleadingly called isReg.
- if ((isReg || isDir) && STRPREFIX(file, QEMU_DEVPREFIX)) {
+ if (isReg && STRPREFIX(file, QEMU_DEVPREFIX)) {
cfg = virQEMUDriverGetConfig(driver);
if (!(target = qemuDomainGetPreservedMountPath(cfg, vm, file)))
Reviewed-by: Ján Tomko <jto...@redhat.com> Jano
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