From e511e3a3b11bf43cd33a9a6f5e4ddcb8b03e45b5 Mon Sep 17 00:00:00 2001
From: Mark Salyzyn <salyzyn@google.com>
Date: Wed, 29 Aug 2018 10:44:33 -0700
Subject: [PATCH 1/2] fs_mgr: Add fs_mgr_overlayfs_required_devices()

Added fs_mgr_overlayfs_required_devices() as hint to init to make sure
the device gets created before fs_mgr_overlayfs_mount_all().

Test: manual
Bug: 109821005
Change-Id: Iab038f3e0252a357b082bb08db3679512b9badec
---
 fs_mgr/fs_mgr_overlayfs.cpp       | 8 ++++++++
 fs_mgr/include/fs_mgr_overlayfs.h | 2 ++
 init/first_stage_mount.cpp        | 6 ++++++
 3 files changed, 16 insertions(+)

diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index ee63d60e8..e50ad2b7d 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -53,6 +53,10 @@ bool fs_mgr_overlayfs_mount_all(const fstab*) {
     return false;
 }
 
+std::vector<std::string> fs_mgr_overlayfs_required_devices(const fstab*) {
+    return {};
+}
+
 bool fs_mgr_overlayfs_setup(const char*, const char*, bool* change) {
     if (change) *change = false;
     return false;
@@ -467,6 +471,10 @@ bool fs_mgr_overlayfs_mount_all(const fstab* fstab) {
     return ret;
 }
 
+std::vector<std::string> fs_mgr_overlayfs_required_devices(const fstab*) {
+    return {};
+}
+
 // Returns false if setup not permitted, errno set to last error.
 // If something is altered, set *change.
 bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool* change) {
diff --git a/fs_mgr/include/fs_mgr_overlayfs.h b/fs_mgr/include/fs_mgr_overlayfs.h
index 251dd9b91..3274e0ec3 100644
--- a/fs_mgr/include/fs_mgr_overlayfs.h
+++ b/fs_mgr/include/fs_mgr_overlayfs.h
@@ -19,8 +19,10 @@
 #include <fstab/fstab.h>
 
 #include <string>
+#include <vector>
 
 bool fs_mgr_overlayfs_mount_all(const fstab* fstab);
+std::vector<std::string> fs_mgr_overlayfs_required_devices(const fstab* fstab);
 bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,
                             bool* change = nullptr);
 bool fs_mgr_overlayfs_teardown(const char* mount_point = nullptr, bool* change = nullptr);
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index 684bf1f13..eb86eb087 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -391,6 +391,12 @@ bool FirstStageMount::MountPartitions() {
         }
     }
 
+    // heads up for instantiating required device(s) for overlayfs logic
+    const auto devices = fs_mgr_overlayfs_required_devices(device_tree_fstab_.get());
+    for (auto const& device : devices) {
+        InitMappedDevice(device);
+    }
+
     fs_mgr_overlayfs_mount_all(device_tree_fstab_.get());
 
     return true;

From 780db02f7d6bfa2e0233521d3aa105d3c10ce8af Mon Sep 17 00:00:00 2001
From: Mark Salyzyn <salyzyn@google.com>
Date: Wed, 6 Jun 2018 13:10:40 -0700
Subject: [PATCH 2/2] fs_mgr: split out fs_mgr_overlayfs_setup_dir()

In preparation for adding a list of possible backing storage.

Test: compile
Bug: 109821005
Change-Id: If3664d44c232db32f79b1355799ec239cfe7633a
---
 fs_mgr/fs_mgr_overlayfs.cpp | 38 ++++++++++++++++++++++++-------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index e50ad2b7d..1edd573d4 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -298,6 +298,28 @@ bool fs_mgr_rm_all(const std::string& path, bool* change = nullptr) {
 
 constexpr char kOverlayfsFileContext[] = "u:object_r:overlayfs_file:s0";
 
+bool fs_mgr_overlayfs_setup_dir(const std::string& dir, std::string* overlay, bool* change) {
+    auto ret = true;
+    auto top = dir + kOverlayTopDir;
+    if (setfscreatecon(kOverlayfsFileContext)) {
+        ret = false;
+        PERROR << "setfscreatecon " << kOverlayfsFileContext;
+    }
+    auto save_errno = errno;
+    if (!mkdir(top.c_str(), 0755)) {
+        if (change) *change = true;
+    } else if (errno != EEXIST) {
+        ret = false;
+        PERROR << "mkdir " << top;
+    } else {
+        errno = save_errno;
+    }
+    setfscreatecon(nullptr);
+
+    if (overlay) *overlay = std::move(top);
+    return ret;
+}
+
 bool fs_mgr_overlayfs_setup_one(const std::string& overlay, const std::string& mount_point,
                                 bool* change) {
     auto ret = true;
@@ -497,19 +519,9 @@ bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool*
     auto mounts = fs_mgr_candidate_list(fstab.get(), fs_mgr_mount_point(fstab.get(), mount_point));
     if (fstab && mounts.empty()) return ret;
 
-    if (setfscreatecon(kOverlayfsFileContext)) {
-        PERROR << "setfscreatecon " << kOverlayfsFileContext;
-    }
-    auto overlay = kOverlayMountPoint + kOverlayTopDir;
-    auto save_errno = errno;
-    if (!mkdir(overlay.c_str(), 0755)) {
-        if (change) *change = true;
-    } else if (errno != EEXIST) {
-        PERROR << "mkdir " << overlay;
-    } else {
-        errno = save_errno;
-    }
-    setfscreatecon(nullptr);
+    std::string overlay;
+    ret |= fs_mgr_overlayfs_setup_dir(kOverlayMountPoint, &overlay, change);
+
     if (!fstab && mount_point && fs_mgr_overlayfs_setup_one(overlay, mount_point, change)) {
         ret = true;
     }