/* this is a raw syscall - man 2 pivot_root */
extern int pivot_root(const char *new_root, const char *put_old);
+/**
+ * mount_move - move mounted point to the new location
+ *
+ * @oldroot: directory that is current location of mount point
+ * @newroot: new directory for the mount point
+ */
int
-mount_move(char *oldroot, char *newroot, char *dir)
+mount_move(const char *oldroot, const char *newroot, const char *dir)
{
#ifndef MS_MOVE
#define MS_MOVE (1 << 13)
ret = mount(olddir, newdir, NULL, MS_NOATIME | MS_MOVE, NULL);
/* if (ret)
- fprintf(stderr, "failed %s %s: %s\n", olddir, newdir, strerror(errno));*/
+ ULOG_ERR("failed %s %s: %m\n", olddir, newdir);*/
return ret;
}
ret = pivot_root(new, pivotdir);
if (ret < 0) {
- fprintf(stderr, "pivot_root failed %s %s: %s\n", new, pivotdir, strerror(errno));
+ ULOG_ERR("pivot_root failed %s %s: %m\n", new, pivotdir);
return -1;
}
return 0;
}
+/**
+ * fopivot - switch to overlay using passed dir as upper one
+ *
+ * @rw_root: writable directory that will be used as upper dir
+ * @ro_root: directory where old root will be put
+ */
int
fopivot(char *rw_root, char *ro_root)
{
- char overlay[64], lowerdir[64];
+ char overlay[64], mount_options[64];
if (find_filesystem("overlay")) {
- fprintf(stderr, "BUG: no suitable fs found\n");
+ ULOG_ERR("BUG: no suitable fs found\n");
return -1;
}
snprintf(overlay, sizeof(overlay), "overlayfs:%s", rw_root);
- snprintf(lowerdir, sizeof(lowerdir), "lowerdir=/,upperdir=%s", rw_root);
- if (mount(overlay, "/mnt", "overlayfs", MS_NOATIME, lowerdir)) {
- fprintf(stderr, "mount failed: %s\n", strerror(errno));
- return -1;
+ /*
+ * First, try to mount without a workdir, for overlayfs v22 and before.
+ * If it fails, it means that we are probably using a v23 and
+ * later versions that require a workdir
+ */
+ snprintf(mount_options, sizeof(mount_options), "lowerdir=/,upperdir=%s", rw_root);
+ if (mount(overlay, "/mnt", "overlayfs", MS_NOATIME, mount_options)) {
+ char upperdir[64], workdir[64], upgrade[64], upgrade_dest[64];
+ struct stat st;
+
+ snprintf(upperdir, sizeof(upperdir), "%s/upper", rw_root);
+ snprintf(workdir, sizeof(workdir), "%s/work", rw_root);
+ snprintf(upgrade, sizeof(upgrade), "%s/sysupgrade.tgz", rw_root);
+ snprintf(upgrade_dest, sizeof(upgrade_dest), "%s/sysupgrade.tgz", upperdir);
+ snprintf(mount_options, sizeof(mount_options), "lowerdir=/,upperdir=%s,workdir=%s",
+ upperdir, workdir);
+
+ /*
+ * Overlay FS v23 and later requires both a upper and
+ * a work directory, both on the same filesystem, but
+ * not part of the same subtree.
+ * We can't really deal with these constraints without
+ * creating two new subdirectories in /overlay.
+ */
+ mkdir(upperdir, 0755);
+ mkdir(workdir, 0755);
+
+ if (stat(upgrade, &st) == 0)
+ rename(upgrade, upgrade_dest);
+
+ /* Mainlined overlayfs has been renamed to "overlay", try that first */
+ if (mount(overlay, "/mnt", "overlay", MS_NOATIME, mount_options)) {
+ if (mount(overlay, "/mnt", "overlayfs", MS_NOATIME, mount_options)) {
+ ULOG_ERR("mount failed: %s, options %m\n", mount_options);
+ return -1;
+ }
+ }
}
return pivot("/mnt", ro_root);
}
+/**
+ * ramoverlay - use RAM to store filesystem changes on top of RO root
+ */
int
ramoverlay(void)
{