cgroups: make it extremely obvious that we're transitioning from a flag to a type

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index fb4f9fb7f0416149c819080cfb68eea4deb2a050..501d71a9f7417531a09f0112df1388f985fc1df3 100644 (file)
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -1770,9 +1770,9 @@ __cgfsng_ops static void cgfsng_payload_finalize(struct cgroup_ops *ops)
 }
 
 /* cgroup-full:* is done, no need to create subdirs */
-static inline bool cg_mount_needs_subdirs(int cg_flags)
+static inline bool cg_mount_needs_subdirs(int cgroup_automount_type)
 {
-       switch (cg_flags) {
+       switch (cgroup_automount_type) {
        case LXC_AUTO_CGROUP_RO:
                return true;
        case LXC_AUTO_CGROUP_RW:
@@ -1788,7 +1788,7 @@ static inline bool cg_mount_needs_subdirs(int cg_flags)
  * remount controller ro if needed and bindmount the cgroupfs onto
  * control/the/cg/path.
  */
-static int cg_legacy_mount_controllers(int cg_flags, struct hierarchy *h,
+static int cg_legacy_mount_controllers(int cgroup_automount_type, struct hierarchy *h,
                                       char *controllerpath, char *cgpath,
                                       const char *container_cgroup)
 {
@@ -1796,7 +1796,8 @@ static int cg_legacy_mount_controllers(int cg_flags, struct hierarchy *h,
        int ret, remount_flags;
        int flags = MS_BIND;
 
-       if ((cg_flags == LXC_AUTO_CGROUP_RO) || (cg_flags == LXC_AUTO_CGROUP_MIXED)) {
+       if ((cgroup_automount_type == LXC_AUTO_CGROUP_RO) ||
+           (cgroup_automount_type == LXC_AUTO_CGROUP_MIXED)) {
                ret = mount(controllerpath, controllerpath, "cgroup", MS_BIND, NULL);
                if (ret < 0)
                        return log_error_errno(-1, errno, "Failed to bind mount \"%s\" onto \"%s\"",
@@ -1816,7 +1817,7 @@ static int cg_legacy_mount_controllers(int cg_flags, struct hierarchy *h,
 
        sourcepath = must_make_path(h->mountpoint, h->container_base_path,
                                    container_cgroup, NULL);
-       if (cg_flags == LXC_AUTO_CGROUP_RO)
+       if (cgroup_automount_type == LXC_AUTO_CGROUP_RO)
                flags |= MS_RDONLY;
 
        ret = mount(sourcepath, cgpath, "cgroup", flags, NULL);
@@ -1844,7 +1845,7 @@ static int cg_legacy_mount_controllers(int cg_flags, struct hierarchy *h,
  * uses-cases are mounting cgroup hierarchies in cgroup namespaces and mounting
  * cgroups for the LXC_AUTO_CGROUP_FULL option.
  */
-static int __cgroupfs_mount(int cg_flags, struct hierarchy *h,
+static int __cgroupfs_mount(int cgroup_automount_type, struct hierarchy *h,
                            struct lxc_rootfs *rootfs, int dfd_mnt_cgroupfs,
                            const char *hierarchy_mnt)
 {
@@ -1861,15 +1862,14 @@ static int __cgroupfs_mount(int cg_flags, struct hierarchy *h,
        flags |= MOUNT_ATTR_NODEV;
        flags |= MOUNT_ATTR_RELATIME;
 
-       if ((cg_flags == LXC_AUTO_CGROUP_RO) ||
-           (cg_flags == LXC_AUTO_CGROUP_FULL_RO))
+       if ((cgroup_automount_type == LXC_AUTO_CGROUP_RO) ||
+           (cgroup_automount_type == LXC_AUTO_CGROUP_FULL_RO))
                flags |= MOUNT_ATTR_RDONLY;
 
-       if (is_unified_hierarchy(h)) {
+       if (is_unified_hierarchy(h))
                fstype = "cgroup2";
-       } else {
+       else
                fstype = "cgroup";
-       }
 
        if (can_use_mount_api()) {
                fd_fs = fs_prepare(fstype, -EBADF, "", 0, 0);
@@ -1918,19 +1918,20 @@ static int __cgroupfs_mount(int cg_flags, struct hierarchy *h,
        return 0;
 }
 
-static inline int cgroupfs_mount(int cg_flags, struct hierarchy *h,
+static inline int cgroupfs_mount(int cgroup_automount_type, struct hierarchy *h,
                                 struct lxc_rootfs *rootfs,
                                 int dfd_mnt_cgroupfs, const char *hierarchy_mnt)
 {
-       return __cgroupfs_mount(cg_flags, h, rootfs, dfd_mnt_cgroupfs, hierarchy_mnt);
+       return __cgroupfs_mount(cgroup_automount_type, h, rootfs,
+                               dfd_mnt_cgroupfs, hierarchy_mnt);
 }
 
-static inline int cgroupfs_bind_mount(int cg_flags, struct hierarchy *h,
+static inline int cgroupfs_bind_mount(int cgroup_automount_type, struct hierarchy *h,
                                      struct lxc_rootfs *rootfs,
                                      int dfd_mnt_cgroupfs,
                                      const char *hierarchy_mnt)
 {
-       switch (cg_flags) {
+       switch (cgroup_automount_type) {
        case LXC_AUTO_CGROUP_FULL_RO:
                break;
        case LXC_AUTO_CGROUP_FULL_RW:
@@ -1941,7 +1942,8 @@ static inline int cgroupfs_bind_mount(int cg_flags, struct hierarchy *h,
                return 0;
        }
 
-       return __cgroupfs_mount(cg_flags, h, rootfs, dfd_mnt_cgroupfs, hierarchy_mnt);
+       return __cgroupfs_mount(cgroup_automount_type, h, rootfs,
+                               dfd_mnt_cgroupfs, hierarchy_mnt);
 }
 
 __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
@@ -1949,6 +1951,7 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
 {
        __do_close int dfd_mnt_tmpfs = -EBADF, fd_fs = -EBADF;
        __do_free char *cgroup_root = NULL;
+       int cgroup_automount_type;
        bool in_cgroup_ns = false, wants_force_mount = false;
        struct lxc_conf *conf = handler->conf;
        struct lxc_rootfs *rootfs = &conf->rootfs;
@@ -1994,6 +1997,7 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
        default:
                return log_error_errno(false, EINVAL, "Invalid cgroup mount options specified");
        }
+       cgroup_automount_type = cg_flags;
 
        if (!wants_force_mount) {
                wants_force_mount = !lxc_wants_cap(CAP_SYS_ADMIN, conf);
@@ -2021,8 +2025,8 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
                 * since the parent directory of the container's cgroup is not
                 * accessible to the container.
                 */
-               cg_flags &= ~LXC_AUTO_CGROUP_MIXED;
-               cg_flags &= ~LXC_AUTO_CGROUP_FULL_MIXED;
+               cgroup_automount_type &= ~LXC_AUTO_CGROUP_MIXED;
+               cgroup_automount_type &= ~LXC_AUTO_CGROUP_FULL_MIXED;
        }
 
        if (in_cgroup_ns && !wants_force_mount)
@@ -2067,7 +2071,7 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
                         * 11. cgroup-full:ro:force    -> Not supported.
                         * 12. cgroup-full:mixed:force -> Not supported.
                         */
-                       ret = cgroupfs_mount(cg_flags, ops->unified, rootfs, dfd_mnt_unified, "");
+                       ret = cgroupfs_mount(cgroup_automount_type, ops->unified, rootfs, dfd_mnt_unified, "");
                        if (ret < 0)
                                return syserrno(false, "Failed to force mount cgroup filesystem in cgroup namespace");
 
@@ -2160,7 +2164,7 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
                         * will not have CAP_SYS_ADMIN after it has started we
                         * need to mount the cgroups manually.
                         */
-                       ret = cgroupfs_mount(cg_flags, h, rootfs, dfd_mnt_tmpfs, controller);
+                       ret = cgroupfs_mount(cgroup_automount_type, h, rootfs, dfd_mnt_tmpfs, controller);
                        if (ret < 0)
                                return false;
 
@@ -2168,11 +2172,11 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
                }
 
                /* Here is where the ancient kernel section begins. */
-               ret = cgroupfs_bind_mount(cg_flags, h, rootfs, dfd_mnt_tmpfs, controller);
+               ret = cgroupfs_bind_mount(cgroup_automount_type, h, rootfs, dfd_mnt_tmpfs, controller);
                if (ret < 0)
                        return false;
 
-               if (!cg_mount_needs_subdirs(cg_flags))
+               if (!cg_mount_needs_subdirs(cgroup_automount_type))
                        continue;
 
                if (!cgroup_root)
@@ -2184,7 +2188,7 @@ __cgfsng_ops static bool cgfsng_mount(struct cgroup_ops *ops,
                if (ret < 0 && (errno != EEXIST))
                        return false;
 
-               ret = cg_legacy_mount_controllers(cg_flags, h, controllerpath, path2, ops->container_cgroup);
+               ret = cg_legacy_mount_controllers(cgroup_automount_type, h, controllerpath, path2, ops->container_cgroup);
                if (ret < 0)
                        return false;
        }