mounts: support mounting partitions

This allows us to map in a whole disk as a loopback device with parition
scanning rather than slicing up the disk and creating several loopback
devices. Something like this:

```
      - type: org.osbuild.copy
        inputs:
          tree:
            type: org.osbuild.tree
            origin: org.osbuild.pipeline
            references:
              - name:tree
        options:
          paths:
            - from: input://tree/
              to: mount://root/
        devices:
          efi:
            type: org.osbuild.loopback
            options:
              filename: disk.img
              start:
                mpp-format-int: '{image.layout[''EFI-SYSTEM''].start}'
              size:
                mpp-format-int: '{image.layout[''EFI-SYSTEM''].size}'
          boot:
            type: org.osbuild.loopback
            options:
              filename: disk.img
              start:
                mpp-format-int: '{image.layout[''boot''].start}'
              size:
                mpp-format-int: '{image.layout[''boot''].size}'
          root:
            type: org.osbuild.loopback
            options:
              filename: disk.img
              start:
                mpp-format-int: '{image.layout[''root''].start}'
              size:
                mpp-format-int: '{image.layout[''root''].size}'
        mounts:
          - name: root
            type: org.osbuild.xfs
            source: root
            target: /
          - name: boot
            type: org.osbuild.ext4
            source: boot
            target: /boot
          - name: efi
            type: org.osbuild.fat
            source: efi
            target: /boot/efi
```

now becomes a little more simple:

```
      - type: org.osbuild.copy
        inputs:
          tree:
            type: org.osbuild.tree
            origin: org.osbuild.pipeline
            references:
              - name:tree
        options:
          paths:
            - from: input://tree/
              to: mount://root/
        devices:
          disk:
            type: org.osbuild.loopback
            options:
              filename: disk.img
              partscan: true
        mounts:
          - name: root
            type: org.osbuild.xfs
            source: disk
            partition:
              mpp-format-int: '{image.layout[''root''].partnum}'
            target: /
          - name: boot
            type: org.osbuild.ext4
            source: disk
            partition:
              mpp-format-int: '{image.layout[''boot''].partnum}'
            target: /boot
          - name: efi
            type: org.osbuild.fat
            source: disk
            partition:
              mpp-format-int: '{image.layout[''EFI-SYSTEM''].partnum}'
            target: /boot/efi
```

Fixes https://github.com/osbuild/osbuild/issues/1495

mounts/org.osbuild.btrfs

@@ -21,6 +21,10 @@ SCHEMA_2 = """
   "source": {
     "type": "string"
   },
+  "partition": {
+    "description": "If the source device has partitions, the partition number, starting at one",
+    "type": "number"
+  },
   "target": {
     "type": "string"
   },

mounts/org.osbuild.ext4

@@ -21,6 +21,10 @@ SCHEMA_2 = """
   "source": {
     "type": "string"
   },
+  "partition": {
+    "description": "If the source device has partitions, the partition number, starting at one",
+    "type": "number"
+  },
   "target": {
     "type": "string"
   },

mounts/org.osbuild.fat

@@ -24,6 +24,10 @@ SCHEMA_2 = """
   "target": {
     "type": "string"
   },
+  "partition": {
+    "description": "If the source device has partitions, the partition number, starting at one",
+    "type": "number"
+  },
   "options": {
     "type": "object",
     "additionalProperties": false,

mounts/org.osbuild.noop

@@ -21,6 +21,9 @@ SCHEMA_2 = """
   "source": {
     "type": "string"
   },
+  "partition": {
+    "type": "number"
+  },
   "target": {
     "type": "string"
   },

mounts/org.osbuild.xfs

@@ -24,6 +24,10 @@ SCHEMA_2 = """
   "target": {
     "type": "string"
   },
+  "partition": {
+    "description": "If the source device has partitions, the partition number, starting at one",
+    "type": "number"
+  },
   "options": {
     "type": "object",
     "additionalProperties": false,

osbuild/formats/v2.py

@@ -286,6 +286,7 @@ def load_mount(description: Dict, index: Index, stage: Stage):
         raise ValueError(f"Duplicated mount '{name}'")
 
     source = description.get("source")
+    partition = description.get("partition")
     target = description.get("target")
 
     options = description.get("options", {})
@@ -296,7 +297,7 @@ def load_mount(description: Dict, index: Index, stage: Stage):
         if not device:
             raise ValueError(f"Unknown device '{source}' for mount '{name}'")
 
-    stage.add_mount(name, info, device, target, options)
+    stage.add_mount(name, info, device, partition, target, options)
 
 
 def load_stage(description: Dict, index: Index, pipeline: Pipeline, manifest: Manifest, source_refs):

osbuild/mounts.py

@@ -23,10 +23,11 @@ class Mount:
     A single mount with its corresponding options
     """
 
-    def __init__(self, name, info, device, target, options: Dict):
+    def __init__(self, name, info, device, partition, target, options: Dict):
         self.name = name
         self.info = info
         self.device = device
+        self.partition = partition
         self.target = target
         self.options = options
         self.id = self.calc_id()
@@ -71,6 +72,11 @@ class MountManager:
         if relpath and os.path.exists(os.path.join('/dev', relpath)):
             source = os.path.join('/dev', relpath)
 
+        # If the user specified a partition then the filesystem to
+        # mount is actually on a partition of the disk.
+        if source and mount.partition:
+            source = f"{source}p{mount.partition}"
+
         root = os.fspath(self.root)
 
         args = {

osbuild/pipeline.py

@@ -111,8 +111,8 @@ class Stage:
         self.devices[name] = dev
         return dev
 
-    def add_mount(self, name, info, device, target, options):
+    def add_mount(self, name, info, device, partition, target, options):
-        mount = Mount(name, info, device, target, options)
+        mount = Mount(name, info, device, partition, target, options)
         self.mounts[name] = mount
         return mount
 

schemas/osbuild2.json

@@ -82,6 +82,9 @@
         "target": {
           "type": "string"
         },
+        "partition": {
+          "type": "number"
+        },
         "options": {
           "type": "object",
           "additionalProperties": true

test/data/manifests/fedora-coreos-container.json

@@ -682,28 +682,11 @@
             ]
           },
           "devices": {
-            "efi": {
+            "disk": {
               "type": "org.osbuild.loopback",
               "options": {
                 "filename": "disk.img",
-                "start": 4096,
+                "partscan": true
-                "size": 260096
-              }
-            },
-            "boot": {
-              "type": "org.osbuild.loopback",
-              "options": {
-                "filename": "disk.img",
-                "start": 264192,
-                "size": 786432
-              }
-            },
-            "root": {
-              "type": "org.osbuild.loopback",
-              "options": {
-                "filename": "disk.img",
-                "start": 1050624,
-                "size": 4194304
               }
             }
           },
@@ -711,19 +694,22 @@
             {
               "name": "root",
               "type": "org.osbuild.xfs",
-              "source": "root",
+              "source": "disk",
+              "partition": 4,
               "target": "/"
             },
             {
               "name": "boot",
               "type": "org.osbuild.ext4",
-              "source": "boot",
+              "source": "disk",
+              "partition": 3,
               "target": "/boot"
             },
             {
               "name": "efi",
               "type": "org.osbuild.fat",
-              "source": "efi",
+              "source": "disk",
+              "partition": 2,
               "target": "/boot/efi"
             }
           ]
@@ -884,30 +870,11 @@
             ]
           },
           "devices": {
-            "efi": {
+            "disk": {
               "type": "org.osbuild.loopback",
               "options": {
                 "filename": "disk.img",
-                "start": 512,
+                "partscan": true,
-                "size": 32512,
-                "sector-size": 4096
-              }
-            },
-            "boot": {
-              "type": "org.osbuild.loopback",
-              "options": {
-                "filename": "disk.img",
-                "start": 33024,
-                "size": 98304,
-                "sector-size": 4096
-              }
-            },
-            "root": {
-              "type": "org.osbuild.loopback",
-              "options": {
-                "filename": "disk.img",
-                "start": 131328,
-                "size": 524288,
                 "sector-size": 4096
               }
             }
@@ -916,19 +883,22 @@
             {
               "name": "root",
               "type": "org.osbuild.xfs",
-              "source": "root",
+              "source": "disk",
+              "partition": 4,
               "target": "/"
             },
             {
               "name": "boot",
               "type": "org.osbuild.ext4",
-              "source": "boot",
+              "source": "disk",
+              "partition": 3,
               "target": "/boot"
             },
             {
               "name": "efi",
               "type": "org.osbuild.fat",
-              "source": "efi",
+              "source": "disk",
+              "partition": 2,
               "target": "/boot/efi"
             }
           ]

test/data/manifests/fedora-coreos-container.mpp.yaml

@@ -207,42 +207,29 @@ pipelines:
             - from: input://tree/
               to: mount://root/
         devices:
-          efi:
+          disk:
             type: org.osbuild.loopback
             options:
               filename: disk.img
-              start:
+              partscan: true
-                mpp-format-int: '{image.layout[''EFI-SYSTEM''].start}'
-              size:
-                mpp-format-int: '{image.layout[''EFI-SYSTEM''].size}'
-          boot:
-            type: org.osbuild.loopback
-            options:
-              filename: disk.img
-              start:
-                mpp-format-int: '{image.layout[''boot''].start}'
-              size:
-                mpp-format-int: '{image.layout[''boot''].size}'
-          root:
-            type: org.osbuild.loopback
-            options:
-              filename: disk.img
-              start:
-                mpp-format-int: '{image.layout[''root''].start}'
-              size:
-                mpp-format-int: '{image.layout[''root''].size}'
         mounts:
           - name: root
             type: org.osbuild.xfs
-            source: root
+            source: disk
+            partition:
+              mpp-format-int: '{image.layout[''root''].partnum}'
             target: /
           - name: boot
             type: org.osbuild.ext4
-            source: boot
+            source: disk
+            partition:
+              mpp-format-int: '{image.layout[''boot''].partnum}'
             target: /boot
           - name: efi
             type: org.osbuild.fat
-            source: efi
+            source: disk
+            partition:
+              mpp-format-int: '{image.layout[''EFI-SYSTEM''].partnum}'
             target: /boot/efi
       - type: org.osbuild.grub2.inst
         options:
@@ -339,48 +326,31 @@ pipelines:
             - from: input://tree/
               to: mount://root/
         devices:
-          efi:
+          disk:
             type: org.osbuild.loopback
             options:
               filename: disk.img
-              start:
+              partscan: true
-                mpp-format-int: '{image4k.layout[''EFI-SYSTEM''].start}'
-              size:
-                mpp-format-int: '{image4k.layout[''EFI-SYSTEM''].size}'
-              sector-size:
-                  mpp-format-int: "{four_k_sector_size}"
-          boot:
-            type: org.osbuild.loopback
-            options:
-              filename: disk.img
-              start:
-                mpp-format-int: '{image4k.layout[''boot''].start}'
-              size:
-                mpp-format-int: '{image4k.layout[''boot''].size}'
-              sector-size:
-                  mpp-format-int: "{four_k_sector_size}"
-          root:
-            type: org.osbuild.loopback
-            options:
-              filename: disk.img
-              start:
-                mpp-format-int: '{image4k.layout[''root''].start}'
-              size:
-                mpp-format-int: '{image4k.layout[''root''].size}'
               sector-size:
                   mpp-format-int: "{four_k_sector_size}"
         mounts:
           - name: root
             type: org.osbuild.xfs
-            source: root
+            source: disk
+            partition:
+              mpp-format-int: '{image4k.layout[''root''].partnum}'
             target: /
           - name: boot
             type: org.osbuild.ext4
-            source: boot
+            source: disk
+            partition:
+              mpp-format-int: '{image4k.layout[''boot''].partnum}'
             target: /boot
           - name: efi
             type: org.osbuild.fat
-            source: efi
+            source: disk
+            partition:
+              mpp-format-int: '{image4k.layout[''EFI-SYSTEM''].partnum}'
             target: /boot/efi
   - name: raw-metal-image
     build: name:build

test/run/test_mount.py

@@ -107,6 +107,7 @@ def mount(mgr, devpath, tree, size, mountpoint, options):
             lpath,
             index.get_module_info("Mount", "org.osbuild.fat"),
             dev,
+            None,
             "/",
             options
         )