diff --git a/Android.mk b/Android.mk
index e92955f..4971ec7 100644
--- a/Android.mk
+++ b/Android.mk
@@ -158,7 +158,10 @@
 LOCAL_TIDY := true
 LOCAL_TIDY_FLAGS := $(common_local_tidy_flags)
 LOCAL_TIDY_CHECKS := $(common_local_tidy_checks)
-LOCAL_SRC_FILES:= secdiscard.cpp
+LOCAL_SRC_FILES:= \
+    FileDeviceUtils.cpp \
+    secdiscard.cpp \
+
 LOCAL_MODULE:= secdiscard
 LOCAL_SHARED_LIBRARIES := libbase
 LOCAL_CFLAGS := $(vold_cflags)
diff --git a/FileDeviceUtils.cpp b/FileDeviceUtils.cpp
new file mode 100644
index 0000000..bc9f4bd
--- /dev/null
+++ b/FileDeviceUtils.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "FileDeviceUtils.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <linux/fiemap.h>
+#include <mntent.h>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
+
+namespace {
+
+std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count);
+
+}
+
+namespace android {
+namespace vold {
+
+// Given a file path, look for the corresponding block device in /proc/mount
+std::string BlockDeviceForPath(const std::string &path)
+{
+    std::unique_ptr<FILE, int(*)(FILE*)> mnts(setmntent("/proc/mounts", "re"), endmntent);
+    if (!mnts) {
+        PLOG(ERROR) << "Unable to open /proc/mounts";
+        return "";
+    }
+    std::string result;
+    size_t best_length = 0;
+    struct mntent *mnt; // getmntent returns a thread local, so it's safe.
+    while ((mnt = getmntent(mnts.get())) != nullptr) {
+        auto l = strlen(mnt->mnt_dir);
+        if (l > best_length &&
+            path.size() > l &&
+            path[l] == '/' &&
+            path.compare(0, l, mnt->mnt_dir) == 0) {
+                result = mnt->mnt_fsname;
+                best_length = l;
+        }
+    }
+    if (result.empty()) {
+        LOG(ERROR) <<"Didn't find a mountpoint to match path " << path;
+        return "";
+    }
+    LOG(DEBUG) << "For path " << path << " block device is " << result;
+    return result;
+}
+
+std::unique_ptr<struct fiemap> PathFiemap(const std::string &path, uint32_t extent_count)
+{
+    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(
+        path.c_str(), O_RDONLY | O_CLOEXEC, 0)));
+    if (fd == -1) {
+        if (errno == ENOENT) {
+            PLOG(DEBUG) << "Unable to open " << path;
+        } else {
+            PLOG(ERROR) << "Unable to open " << path;
+        }
+        return nullptr;
+    }
+    auto fiemap = alloc_fiemap(extent_count);
+    if (ioctl(fd.get(), FS_IOC_FIEMAP, fiemap.get()) != 0) {
+        PLOG(ERROR) << "Unable to FIEMAP " << path;
+        return nullptr;
+    }
+    auto mapped = fiemap->fm_mapped_extents;
+    if (mapped < 1 || mapped > extent_count) {
+        LOG(ERROR) << "Extent count not in bounds 1 <= " << mapped << " <= " << extent_count
+            << " in " << path;
+        return nullptr;
+    }
+    return fiemap;
+}
+
+}  // namespace vold
+}  // namespace android
+
+namespace {
+
+std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count)
+{
+    size_t allocsize = offsetof(struct fiemap, fm_extents[extent_count]);
+    std::unique_ptr<struct fiemap> res(new (::operator new (allocsize)) struct fiemap);
+    memset(res.get(), 0, allocsize);
+    res->fm_start = 0;
+    res->fm_length = UINT64_MAX;
+    res->fm_flags = 0;
+    res->fm_extent_count = extent_count;
+    res->fm_mapped_extents = 0;
+    return res;
+}
+
+}
diff --git a/FileDeviceUtils.h b/FileDeviceUtils.h
new file mode 100644
index 0000000..4c1d49a
--- /dev/null
+++ b/FileDeviceUtils.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_VOLD_FILEDEVICEUTILS_H
+#define ANDROID_VOLD_FILEDEVICEUTILS_H
+
+#include <string>
+#include <linux/fiemap.h>
+
+namespace android {
+namespace vold {
+
+// Given a file path, look for the corresponding block device in /proc/mount
+std::string BlockDeviceForPath(const std::string &path);
+
+// Read the file's FIEMAP
+std::unique_ptr<struct fiemap> PathFiemap(const std::string &path, uint32_t extent_count);
+
+}  // namespace vold
+}  // namespace android
+
+#endif
diff --git a/secdiscard.cpp b/secdiscard.cpp
index a335ab6..f9532ea 100644
--- a/secdiscard.cpp
+++ b/secdiscard.cpp
@@ -31,6 +31,8 @@
 #include <android-base/logging.h>
 #include <android-base/unique_fd.h>
 
+#include "FileDeviceUtils.h"
+
 namespace {
 
 struct Options {
@@ -43,10 +45,7 @@
 bool read_command_line(int argc, const char * const argv[], Options &options);
 void usage(const char *progname);
 bool secdiscard_path(const std::string &path);
-std::unique_ptr<struct fiemap> path_fiemap(const std::string &path, uint32_t extent_count);
 bool check_fiemap(const struct fiemap &fiemap, const std::string &path);
-std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count);
-std::string block_device_for_path(const std::string &path);
 bool overwrite_with_zeros(int fd, off64_t start, off64_t length);
 
 }
@@ -98,11 +97,11 @@
 
 // BLKSECDISCARD all content in "path", if it's small enough.
 bool secdiscard_path(const std::string &path) {
-    auto fiemap = path_fiemap(path, max_extents);
+    auto fiemap = android::vold::PathFiemap(path, max_extents);
     if (!fiemap || !check_fiemap(*fiemap, path)) {
         return false;
     }
-    auto block_device = block_device_for_path(path);
+    auto block_device = android::vold::BlockDeviceForPath(path);
     if (block_device.empty()) {
         return false;
     }
@@ -125,33 +124,6 @@
     return true;
 }
 
-// Read the file's FIEMAP
-std::unique_ptr<struct fiemap> path_fiemap(const std::string &path, uint32_t extent_count)
-{
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(
-        path.c_str(), O_RDONLY | O_CLOEXEC, 0)));
-    if (fd == -1) {
-        if (errno == ENOENT) {
-            PLOG(DEBUG) << "Unable to open " << path;
-        } else {
-            PLOG(ERROR) << "Unable to open " << path;
-        }
-        return nullptr;
-    }
-    auto fiemap = alloc_fiemap(extent_count);
-    if (ioctl(fd.get(), FS_IOC_FIEMAP, fiemap.get()) != 0) {
-        PLOG(ERROR) << "Unable to FIEMAP " << path;
-        return nullptr;
-    }
-    auto mapped = fiemap->fm_mapped_extents;
-    if (mapped < 1 || mapped > extent_count) {
-        LOG(ERROR) << "Extent count not in bounds 1 <= " << mapped << " <= " << extent_count
-            << " in " << path;
-        return nullptr;
-    }
-    return fiemap;
-}
-
 // Ensure that the FIEMAP covers the file and is OK to discard
 bool check_fiemap(const struct fiemap &fiemap, const std::string &path) {
     auto mapped = fiemap.fm_mapped_extents;
@@ -169,48 +141,6 @@
     return true;
 }
 
-std::unique_ptr<struct fiemap> alloc_fiemap(uint32_t extent_count)
-{
-    size_t allocsize = offsetof(struct fiemap, fm_extents[extent_count]);
-    std::unique_ptr<struct fiemap> res(new (::operator new (allocsize)) struct fiemap);
-    memset(res.get(), 0, allocsize);
-    res->fm_start = 0;
-    res->fm_length = UINT64_MAX;
-    res->fm_flags = 0;
-    res->fm_extent_count = extent_count;
-    res->fm_mapped_extents = 0;
-    return res;
-}
-
-// Given a file path, look for the corresponding block device in /proc/mount
-std::string block_device_for_path(const std::string &path)
-{
-    std::unique_ptr<FILE, int(*)(FILE*)> mnts(setmntent("/proc/mounts", "re"), endmntent);
-    if (!mnts) {
-        PLOG(ERROR) << "Unable to open /proc/mounts";
-        return "";
-    }
-    std::string result;
-    size_t best_length = 0;
-    struct mntent *mnt; // getmntent returns a thread local, so it's safe.
-    while ((mnt = getmntent(mnts.get())) != nullptr) {
-        auto l = strlen(mnt->mnt_dir);
-        if (l > best_length &&
-            path.size() > l &&
-            path[l] == '/' &&
-            path.compare(0, l, mnt->mnt_dir) == 0) {
-                result = mnt->mnt_fsname;
-                best_length = l;
-        }
-    }
-    if (result.empty()) {
-        LOG(ERROR) <<"Didn't find a mountpoint to match path " << path;
-        return "";
-    }
-    LOG(DEBUG) << "For path " << path << " block device is " << result;
-    return result;
-}
-
 bool overwrite_with_zeros(int fd, off64_t start, off64_t length) {
     if (lseek64(fd, start, SEEK_SET) != start) {
         PLOG(ERROR) << "Seek failed for zero overwrite";