commit 2b2f423ef694a03f4fd429b1d3fa221619131df4
author David Anderson <dvander@google.com> Mon Oct 29 18:48:56 2018 -0700
committer David Anderson <dvander@google.com> Tue Oct 30 13:47:59 2018 -0700
tree ebf4be0805c18d4bb9f450be8bfcd2742e16845b
parent d84d570d8c5b244befe0c0faf3e310b1cd9caa76

recovery: Fix mounting /system with dynamic partitions.

When using dynamic partitions, the blk_device field in fstab_rec must be
translated to a /dev/block/dm-N node with
fs_mgr_update_logical_partition. However, init will not have created
these nodes to begin with since CreateLogicalPartitions is not called in
recovery. This patch addresses both issues.

Note that flashing system through fastbootd will not work while /system is
mounted.

Bug: 118634720
Test: manual test
Change-Id: I06c83309d09eab6b65245b1ed10c51d05398f23e

recovery_main.cpp

diff --git a/recovery_main.cpp b/recovery_main.cpp
index 7835094..19ef4f3 100644
--- a/recovery_main.cpp
+++ b/recovery_main.cpp
@@ -478,8 +478,13 @@
         break;
 
       case Device::ENTER_FASTBOOT:
-        LOG(INFO) << "Entering fastboot";
-        fastboot = true;
+        if (logical_partitions_mapped()) {
+          ui->Print("Partitions may be mounted - rebooting to enter fastboot.");
+          android::base::SetProperty(ANDROID_RB_PROPERTY, "reboot,fastboot");
+        } else {
+          LOG(INFO) << "Entering fastboot";
+          fastboot = true;
+        }
         break;
 
       case Device::ENTER_RECOVERY:

roots.cpp

diff --git a/roots.cpp b/roots.cpp
index c29771a..dc34784 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -38,10 +38,12 @@
 #include <cryptfs.h>
 #include <ext4_utils/wipe.h>
 #include <fs_mgr.h>
+#include <fs_mgr_dm_linear.h>
 
 #include "otautil/mounts.h"
 
 static struct fstab* fstab = nullptr;
+static bool did_map_logical_partitions = false;
 
 extern struct selabel_handle* sehandle;
 
@@ -117,6 +119,25 @@
     mount_point = v->mount_point;
   }
 
+  // If we can't acquire the block device for a logical partition, it likely
+  // was never created. In that case we try to create it.
+  if (fs_mgr_is_logical(v) && !fs_mgr_update_logical_partition(v)) {
+    if (did_map_logical_partitions) {
+      LOG(ERROR) << "Failed to find block device for partition";
+      return -1;
+    }
+    std::string super_name = fs_mgr_get_super_partition_name();
+    if (!android::fs_mgr::CreateLogicalPartitions(super_name)) {
+      LOG(ERROR) << "Failed to create logical partitions";
+      return -1;
+    }
+    did_map_logical_partitions = true;
+    if (!fs_mgr_update_logical_partition(v)) {
+      LOG(ERROR) << "Failed to find block device for partition";
+      return -1;
+    }
+  }
+
   const MountedVolume* mv = find_mounted_volume_by_mount_point(mount_point);
   if (mv != nullptr) {
     // Volume is already mounted.
@@ -387,3 +408,7 @@
   }
   return 0;
 }
+
+bool logical_partitions_mapped() {
+  return did_map_logical_partitions;
+}

roots.h

diff --git a/roots.h b/roots.h
index 46bb77e..702af8d 100644
--- a/roots.h
+++ b/roots.h
@@ -53,4 +53,6 @@
 // mounted (/tmp and /cache) are mounted.  Returns 0 on success.
 int setup_install_mounts();
 
+bool logical_partitions_mapped();
+
 #endif  // RECOVERY_ROOTS_H_