From: Daniel P. Berrange berra...@redhat.com
If a cgroup controller is co-mounted with another, eg
/sys/fs/cgroup/cpu,cpuacct
Then it is a requirement that there exist symlinks at
/sys/fs/cgroup/cpu
/sys/fs/cgroup/cpuacct
pointing to the real mount point. Add support to virCgroupPtr
to detect and track these symlinks
Signed-off-by: Daniel P. Berrange berra...@redhat.com
---
src/util/vircgroup.c | 56 ++
src/util/vircgrouppriv.h | 5 +
tests/vircgroupmock.c| 58
tests/vircgrouptest.c| 36 +++---
4 files changed, 143 insertions(+), 12 deletions(-)
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 6202614..14af16e 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -75,6 +75,7 @@ void virCgroupFree(virCgroupPtr *group)
for (i = 0 ; i VIR_CGROUP_CONTROLLER_LAST ; i++) {
VIR_FREE((*group)-controllers[i].mountPoint);
+VIR_FREE((*group)-controllers[i].linkPoint);
VIR_FREE((*group)-controllers[i].placement);
}
@@ -114,6 +115,14 @@ static int virCgroupCopyMounts(virCgroupPtr group,
if (!group-controllers[i].mountPoint)
return -ENOMEM;
+
+if (parent-controllers[i].linkPoint) {
+group-controllers[i].linkPoint =
+strdup(parent-controllers[i].linkPoint);
+
+if (!group-controllers[i].linkPoint)
+return -ENOMEM;
+}
}
return 0;
}
@@ -157,9 +166,46 @@ static int virCgroupDetectMounts(virCgroupPtr group)
* first entry only
*/
if (typelen == len STREQLEN(typestr, tmp, len)
-!group-controllers[i].mountPoint
-!(group-controllers[i].mountPoint =
strdup(entry.mnt_dir)))
-goto no_memory;
+!group-controllers[i].mountPoint) {
+char *linksrc;
+struct stat sb;
+char *tmp2;
+
+if (!(group-controllers[i].mountPoint =
strdup(entry.mnt_dir)))
+goto no_memory;
+
+tmp2 = strrchr(entry.mnt_dir, '/');
+if (!tmp2) {
+errno = EINVAL;
+goto error;
+}
+*tmp2 = '\0';
+/* If it is a co-mount it has a filename like cpu,cpuacct
+ * and we must identify the symlink path */
+if (strchr(tmp2 + 1, ',')) {
+if (virAsprintf(linksrc, %s/%s,
+entry.mnt_dir, typestr) 0)
+goto no_memory;
+*tmp2 = '/';
+
+if (lstat(linksrc, sb) 0) {
+if (errno == ENOENT) {
+VIR_WARN(Controller %s co-mounted at %s is
missing symlink at %s,
+ typestr, entry.mnt_dir, linksrc);
+VIR_FREE(linksrc);
+} else {
+goto error;
+}
+} else {
+if (!S_ISLNK(sb.st_mode)) {
+VIR_WARN(Expecting a symlink at %s for
controller %s,
+ linksrc, typestr);
+} else {
+group-controllers[i].linkPoint = linksrc;
+}
+}
+}
+}
tmp = next;
}
}
@@ -170,8 +216,10 @@ static int virCgroupDetectMounts(virCgroupPtr group)
return 0;
no_memory:
+errno = ENOENT;
+error:
VIR_FORCE_FCLOSE(mounts);
-return -ENOMEM;
+return -errno;
}
diff --git a/src/util/vircgrouppriv.h b/src/util/vircgrouppriv.h
index cc8cc0b..582be79 100644
--- a/src/util/vircgrouppriv.h
+++ b/src/util/vircgrouppriv.h
@@ -34,6 +34,11 @@
struct virCgroupController {
int type;
char *mountPoint;
+/* If mountPoint holds several controllers co-mounted,
+ * then linkPoint is path of the symlink to the mountPoint
+ * for just the one controller
+ */
+char *linkPoint;
char *placement;
};
diff --git a/tests/vircgroupmock.c b/tests/vircgroupmock.c
index e50f7e0..32f074b 100644
--- a/tests/vircgroupmock.c
+++ b/tests/vircgroupmock.c
@@ -32,6 +32,8 @@
static int (*realopen)(const char *path, int flags, ...);
static FILE *(*realfopen)(const char *path, const char *mode);
static int (*realaccess)(const char *path, int mode);
+static int (*reallstat)(const char *path, struct stat *sb);
+static int (*real__lxstat)(int ver, const char *path, struct stat *sb);
static int (*realmkdir)(const char
