[fwutil]: Use overlay driver when mounting next image filesystem (#825)

* [fwutil]: Use overlay driver when mounting next image filesystem.

Signed-off-by: Nazarii Hnydyn <[email protected]>

* [fwutil]: Update command reference.

Signed-off-by: Nazarii Hnydyn <[email protected]>

Author: nazariig

doc/Command-Reference.md

@@ -4117,7 +4117,7 @@ Supported options:
 2. -f|--force - install FW regardless the current version
 3. -i|--image - update FW using current/next SONiC image
 
-Note: the default option is --image=current
+Note: the default option is --image=current (current/next values are taken from `sonic_installer list`)
 
 Go Back To [Beginning of the document](#) or [Beginning of this section](#platform-component-firmware)
 

fwutil/lib.py

@@ -201,50 +201,77 @@ class SquashFs(object):
     OS_PREFIX = "SONiC-OS-"
 
     FS_PATH_TEMPLATE = "/host/image-{}/fs.squashfs"
+    FS_RW_TEMPLATE = "/host/image-{}/rw"
+    FS_WORK_TEMPLATE = "/host/image-{}/work"
     FS_MOUNTPOINT_TEMPLATE = "/tmp/image-{}-fs"
 
-    def __init__(self):
-        current_image = self.__get_current_image()
-        next_image = self.__get_next_image()
-
-        if current_image == next_image:
-            raise RuntimeError("Next boot image is not set")
+    OVERLAY_MOUNTPOINT_TEMPLATE = "/tmp/image-{}-overlay"
 
-        image_stem = next_image.lstrip(self.OS_PREFIX)
+    def __init__(self):
+        image_stem = self.next_image.lstrip(self.OS_PREFIX)
 
         self.fs_path = self.FS_PATH_TEMPLATE.format(image_stem)
+        self.fs_rw = self.FS_RW_TEMPLATE.format(image_stem)
+        self.fs_work = self.FS_WORK_TEMPLATE.format(image_stem)
         self.fs_mountpoint = self.FS_MOUNTPOINT_TEMPLATE.format(image_stem)
 
-    def __get_current_image(self):
+        self.overlay_mountpoint = self.OVERLAY_MOUNTPOINT_TEMPLATE.format(image_stem)
+
+    def get_current_image(self):
         cmd = "sonic_installer list | grep 'Current: ' | cut -f2 -d' '"
         output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
 
         return output.rstrip(NEWLINE)
 
-    def __get_next_image(self):
+    def get_next_image(self):
         cmd = "sonic_installer list | grep 'Next: ' | cut -f2 -d' '"
         output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
 
         return output.rstrip(NEWLINE)
 
+    def is_next_boot_set(self):
+        return self.current_image != self.next_image
+
     def mount_next_image_fs(self):
-        if os.path.ismount(self.fs_mountpoint):
+        if os.path.ismount(self.fs_mountpoint) or os.path.ismount(self.overlay_mountpoint):
             self.umount_next_image_fs()
 
         os.mkdir(self.fs_mountpoint)
-        cmd = "mount -t squashfs {} {}".format(self.fs_path, self.fs_mountpoint)
+        cmd = "mount -t squashfs {} {}".format(
+            self.fs_path,
+            self.fs_mountpoint
+        )
         subprocess.check_call(cmd, shell=True)
 
-        return self.fs_mountpoint
+        os.mkdir(self.overlay_mountpoint)
+        cmd = "mount -n -r -t overlay -o lowerdir={},upperdir={},workdir={} overlay {}".format(
+            self.fs_mountpoint,
+            self.fs_rw,
+            self.fs_work,
+            self.overlay_mountpoint
+        )
+        subprocess.check_call(cmd, shell=True)
+
+        return self.overlay_mountpoint
 
     def umount_next_image_fs(self):
+        if os.path.ismount(self.overlay_mountpoint):
+            cmd = "umount -rf {}".format(self.overlay_mountpoint)
+            subprocess.check_call(cmd, shell=True)
+
+        if os.path.exists(self.overlay_mountpoint):
+            os.rmdir(self.overlay_mountpoint)
+
         if os.path.ismount(self.fs_mountpoint):
             cmd = "umount -rf {}".format(self.fs_mountpoint)
             subprocess.check_call(cmd, shell=True)
 
         if os.path.exists(self.fs_mountpoint):
             os.rmdir(self.fs_mountpoint)
 
+    current_image = property(fget=get_current_image)
+    next_image = property(fget=get_next_image)
+
 
 class PlatformComponentsParser(object):
     """

fwutil/log.py

@@ -124,3 +124,6 @@ def log_fw_install_end(self, component, firmware, status, exception=None):
 
     def print_error(self, msg):
         click.echo("Error: {}.".format(msg))
+
+    def print_warning(self, msg):
+        click.echo("Warning: {}.".format(msg))

fwutil/main.py

@@ -227,14 +227,16 @@ def update(ctx, yes, force, image):
         squashfs = None
 
         try:
-            cup = None
+            cup = ComponentUpdateProvider()
 
             if image == IMAGE_NEXT:
                 squashfs = SquashFs()
-                fs_path = squashfs.mount_next_image_fs()
-                cup = ComponentUpdateProvider(fs_path)
-            else:
-                cup = ComponentUpdateProvider()
+
+                if squashfs.is_next_boot_set():
+                    fs_path = squashfs.mount_next_image_fs()
+                    cup = ComponentUpdateProvider(fs_path)
+                else:
+                    log_helper.print_warning("Next boot is set to current: fallback to defaults")
 
             click.echo(cup.get_status(force))