diff --git a/cmds/installd/Android.bp b/cmds/installd/Android.bp
index 9d0d8ba..3c42ede 100644
--- a/cmds/installd/Android.bp
+++ b/cmds/installd/Android.bp
@@ -14,6 +14,7 @@
         "CacheItem.cpp",
         "CacheTracker.cpp",
         "InstalldNativeService.cpp",
+        "QuotaUtils.cpp",
         "dexopt.cpp",
         "globals.cpp",
         "utils.cpp",
diff --git a/cmds/installd/CacheTracker.cpp b/cmds/installd/CacheTracker.cpp
index a7242c3..8b868fb 100644
--- a/cmds/installd/CacheTracker.cpp
+++ b/cmds/installd/CacheTracker.cpp
@@ -19,13 +19,13 @@
 #include "CacheTracker.h"
 
 #include <fts.h>
-#include <sys/quota.h>
 #include <sys/xattr.h>
 #include <utils/Trace.h>
 
 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 
+#include "QuotaUtils.h"
 #include "utils.h"
 
 using android::base::StringPrintf;
@@ -33,9 +33,13 @@
 namespace android {
 namespace installd {
 
-CacheTracker::CacheTracker(userid_t userId, appid_t appId, const std::string& quotaDevice) :
-        cacheUsed(0), cacheQuota(0), mUserId(userId), mAppId(appId), mQuotaDevice(quotaDevice),
-        mItemsLoaded(false) {
+CacheTracker::CacheTracker(userid_t userId, appid_t appId, const std::string& uuid)
+      : cacheUsed(0),
+        cacheQuota(0),
+        mUserId(userId),
+        mAppId(appId),
+        mItemsLoaded(false),
+        mUuid(uuid) {
 }
 
 CacheTracker::~CacheTracker() {
@@ -72,26 +76,18 @@
 bool CacheTracker::loadQuotaStats() {
     int cacheGid = multiuser_get_cache_gid(mUserId, mAppId);
     int extCacheGid = multiuser_get_ext_cache_gid(mUserId, mAppId);
-    if (!mQuotaDevice.empty() && cacheGid != -1 && extCacheGid != -1) {
-        struct dqblk dq;
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), mQuotaDevice.c_str(), cacheGid,
-                reinterpret_cast<char*>(&dq)) != 0) {
-            if (errno != ESRCH) {
-                PLOG(ERROR) << "Failed to quotactl " << mQuotaDevice << " for GID " << cacheGid;
-            }
-            return false;
+    if (IsQuotaSupported(mUuid) && cacheGid != -1 && extCacheGid != -1) {
+        int64_t space;
+        if ((space = GetOccupiedSpaceForGid(mUuid, cacheGid)) != -1) {
+            cacheUsed += space;
         } else {
-            cacheUsed += dq.dqb_curspace;
+            return false;
         }
 
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), mQuotaDevice.c_str(), extCacheGid,
-                reinterpret_cast<char*>(&dq)) != 0) {
-            if (errno != ESRCH) {
-                PLOG(ERROR) << "Failed to quotactl " << mQuotaDevice << " for GID " << cacheGid;
-            }
-            return false;
+        if ((space = GetOccupiedSpaceForGid(mUuid, extCacheGid)) != -1) {
+            cacheUsed += space;
         } else {
-            cacheUsed += dq.dqb_curspace;
+            return false;
         }
         return true;
     } else {
diff --git a/cmds/installd/CacheTracker.h b/cmds/installd/CacheTracker.h
index 44359b4..b0527e7 100644
--- a/cmds/installd/CacheTracker.h
+++ b/cmds/installd/CacheTracker.h
@@ -39,7 +39,7 @@
  */
 class CacheTracker {
 public:
-    CacheTracker(userid_t userId, appid_t appId, const std::string& quotaDevice);
+    CacheTracker(userid_t userId, appid_t appId, const std::string& uuid);
     ~CacheTracker();
 
     std::string toString();
@@ -61,8 +61,8 @@
 private:
     userid_t mUserId;
     appid_t mAppId;
-    std::string mQuotaDevice;
     bool mItemsLoaded;
+    const std::string& mUuid;
 
     std::vector<std::string> mDataPaths;
 
diff --git a/cmds/installd/InstalldNativeService.cpp b/cmds/installd/InstalldNativeService.cpp
index 28ffdf1..2439dff 100644
--- a/cmds/installd/InstalldNativeService.cpp
+++ b/cmds/installd/InstalldNativeService.cpp
@@ -31,7 +31,6 @@
 #include <sys/file.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
-#include <sys/quota.h>
 #include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/statvfs.h>
@@ -64,6 +63,7 @@
 
 #include "CacheTracker.h"
 #include "MatchExtensionGen.h"
+#include "QuotaUtils.h"
 
 #ifndef LOG_TAG
 #define LOG_TAG "installd"
@@ -266,11 +266,6 @@
         for (const auto& n : mStorageMounts) {
             out << "    " << n.first << " = " << n.second << endl;
         }
-
-        out << endl << "Quota reverse mounts:" << endl;
-        for (const auto& n : mQuotaReverseMounts) {
-            out << "    " << n.first << " = " << n.second << endl;
-        }
     }
 
     {
@@ -950,9 +945,9 @@
     CHECK_ARGUMENT_UUID(uuid);
     std::lock_guard<std::recursive_mutex> lock(mLock);
 
+    auto uuidString = uuid ? *uuid : "";
     const char* uuid_ = uuid ? uuid->c_str() : nullptr;
     auto data_path = create_data_path(uuid_);
-    auto device = findQuotaDeviceForUuid(uuid);
     auto noop = (flags & FLAG_FREE_CACHE_NOOP);
 
     int64_t free = data_disk_free(data_path);
@@ -999,7 +994,7 @@
                         search->second->addDataPath(p->fts_path);
                     } else {
                         auto tracker = std::shared_ptr<CacheTracker>(new CacheTracker(
-                                multiuser_get_user_id(uid), multiuser_get_app_id(uid), device));
+                                multiuser_get_user_id(uid), multiuser_get_app_id(uid), uuidString));
                         tracker->addDataPath(p->fts_path);
                         {
                             std::lock_guard<std::recursive_mutex> lock(mQuotasLock);
@@ -1164,53 +1159,26 @@
 }
 #endif
 
-static void collectQuotaStats(const std::string& device, int32_t userId,
+static void collectQuotaStats(const std::string& uuid, int32_t userId,
         int32_t appId, struct stats* stats, struct stats* extStats) {
-    if (device.empty()) return;
-
-    struct dqblk dq;
-
+    int64_t space;
     if (stats != nullptr) {
         uid_t uid = multiuser_get_uid(userId, appId);
-        if (quotactl(QCMD(Q_GETQUOTA, USRQUOTA), device.c_str(), uid,
-                reinterpret_cast<char*>(&dq)) != 0) {
-            if (errno != ESRCH) {
-                PLOG(ERROR) << "Failed to quotactl " << device << " for UID " << uid;
-            }
-        } else {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for UID " << uid << " " << dq.dqb_curspace;
-#endif
-            stats->dataSize += dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForUid(uuid, uid)) != -1) {
+            stats->dataSize += space;
         }
 
         int cacheGid = multiuser_get_cache_gid(userId, appId);
         if (cacheGid != -1) {
-            if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), cacheGid,
-                    reinterpret_cast<char*>(&dq)) != 0) {
-                if (errno != ESRCH) {
-                    PLOG(ERROR) << "Failed to quotactl " << device << " for GID " << cacheGid;
-                }
-            } else {
-#if MEASURE_DEBUG
-                LOG(DEBUG) << "quotactl() for GID " << cacheGid << " " << dq.dqb_curspace;
-#endif
-                stats->cacheSize += dq.dqb_curspace;
+            if ((space = GetOccupiedSpaceForGid(uuid, cacheGid)) != -1) {
+                stats->cacheSize += space;
             }
         }
 
         int sharedGid = multiuser_get_shared_gid(0, appId);
         if (sharedGid != -1) {
-            if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), sharedGid,
-                    reinterpret_cast<char*>(&dq)) != 0) {
-                if (errno != ESRCH) {
-                    PLOG(ERROR) << "Failed to quotactl " << device << " for GID " << sharedGid;
-                }
-            } else {
-#if MEASURE_DEBUG
-                LOG(DEBUG) << "quotactl() for GID " << sharedGid << " " << dq.dqb_curspace;
-#endif
-                stats->codeSize += dq.dqb_curspace;
+            if ((space = GetOccupiedSpaceForGid(uuid, sharedGid)) != -1) {
+                stats->codeSize += space;
             }
         }
     }
@@ -1218,32 +1186,16 @@
     if (extStats != nullptr) {
         int extGid = multiuser_get_ext_gid(userId, appId);
         if (extGid != -1) {
-            if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), extGid,
-                    reinterpret_cast<char*>(&dq)) != 0) {
-                if (errno != ESRCH) {
-                    PLOG(ERROR) << "Failed to quotactl " << device << " for GID " << extGid;
-                }
-            } else {
-#if MEASURE_DEBUG
-                LOG(DEBUG) << "quotactl() for GID " << extGid << " " << dq.dqb_curspace;
-#endif
-                extStats->dataSize += dq.dqb_curspace;
+            if ((space = GetOccupiedSpaceForGid(uuid, extGid)) != -1) {
+                extStats->dataSize += space;
             }
         }
 
         int extCacheGid = multiuser_get_ext_cache_gid(userId, appId);
         if (extCacheGid != -1) {
-            if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), extCacheGid,
-                    reinterpret_cast<char*>(&dq)) != 0) {
-                if (errno != ESRCH) {
-                    PLOG(ERROR) << "Failed to quotactl " << device << " for GID " << extCacheGid;
-                }
-            } else {
-#if MEASURE_DEBUG
-                LOG(DEBUG) << "quotactl() for GID " << extCacheGid << " " << dq.dqb_curspace;
-#endif
-                extStats->dataSize += dq.dqb_curspace;
-                extStats->cacheSize += dq.dqb_curspace;
+            if ((space = GetOccupiedSpaceForGid(uuid, extCacheGid)) != -1) {
+                extStats->dataSize += space;
+                extStats->cacheSize += space;
             }
         }
     }
@@ -1407,10 +1359,10 @@
     memset(&stats, 0, sizeof(stats));
     memset(&extStats, 0, sizeof(extStats));
 
+    auto uuidString = uuid ? *uuid : "";
     const char* uuid_ = uuid ? uuid->c_str() : nullptr;
 
-    auto device = findQuotaDeviceForUuid(uuid);
-    if (device.empty()) {
+    if (!IsQuotaSupported(uuidString)) {
         flags &= ~FLAG_USE_QUOTA;
     }
 
@@ -1430,7 +1382,7 @@
         ATRACE_END();
 
         ATRACE_BEGIN("quota");
-        collectQuotaStats(device, userId, appId, &stats, &extStats);
+        collectQuotaStats(uuidString, userId, appId, &stats, &extStats);
         ATRACE_END();
     } else {
         ATRACE_BEGIN("code");
@@ -1513,27 +1465,19 @@
     memset(&stats, 0, sizeof(stats));
     memset(&extStats, 0, sizeof(extStats));
 
+    auto uuidString = uuid ? *uuid : "";
     const char* uuid_ = uuid ? uuid->c_str() : nullptr;
 
-    auto device = findQuotaDeviceForUuid(uuid);
-    if (device.empty()) {
+    if (!IsQuotaSupported(uuidString)) {
         flags &= ~FLAG_USE_QUOTA;
     }
 
     if (flags & FLAG_USE_QUOTA) {
-        struct dqblk dq;
+        int64_t space;
 
         ATRACE_BEGIN("obb");
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), AID_MEDIA_OBB,
-                reinterpret_cast<char*>(&dq)) != 0) {
-            if (errno != ESRCH) {
-                PLOG(ERROR) << "Failed to quotactl " << device << " for GID " << AID_MEDIA_OBB;
-            }
-        } else {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for GID " << AID_MEDIA_OBB << " " << dq.dqb_curspace;
-#endif
-            extStats.codeSize += dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForGid(uuidString, AID_MEDIA_OBB)) != -1) {
+            extStats.codeSize += space;
         }
         ATRACE_END();
 
@@ -1559,16 +1503,8 @@
 
         ATRACE_BEGIN("external");
         uid_t uid = multiuser_get_uid(userId, AID_MEDIA_RW);
-        if (quotactl(QCMD(Q_GETQUOTA, USRQUOTA), device.c_str(), uid,
-                reinterpret_cast<char*>(&dq)) != 0) {
-            if (errno != ESRCH) {
-                PLOG(ERROR) << "Failed to quotactl " << device << " for UID " << uid;
-            }
-        } else {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for UID " << uid << " " << dq.dqb_curspace;
-#endif
-            extStats.dataSize += dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForUid(uuidString, uid)) != -1) {
+            extStats.dataSize += space;
         }
         ATRACE_END();
 
@@ -1585,7 +1521,7 @@
         int64_t dataSize = extStats.dataSize;
         for (auto appId : appIds) {
             if (appId >= AID_APP_START) {
-                collectQuotaStats(device, userId, appId, &stats, &extStats);
+                collectQuotaStats(uuidString, userId, appId, &stats, &extStats);
 
 #if MEASURE_DEBUG
                 // Sleep to make sure we don't lose logs
@@ -1667,6 +1603,7 @@
     LOG(INFO) << "Measuring external " << userId;
 #endif
 
+    auto uuidString = uuid ? *uuid : "";
     const char* uuid_ = uuid ? uuid->c_str() : nullptr;
 
     int64_t totalSize = 0;
@@ -1676,58 +1613,33 @@
     int64_t appSize = 0;
     int64_t obbSize = 0;
 
-    auto device = findQuotaDeviceForUuid(uuid);
-    if (device.empty()) {
+    if (!IsQuotaSupported(uuidString)) {
         flags &= ~FLAG_USE_QUOTA;
     }
 
     if (flags & FLAG_USE_QUOTA) {
-        struct dqblk dq;
+        int64_t space;
 
         ATRACE_BEGIN("quota");
         uid_t uid = multiuser_get_uid(userId, AID_MEDIA_RW);
-        if (quotactl(QCMD(Q_GETQUOTA, USRQUOTA), device.c_str(), uid,
-                reinterpret_cast<char*>(&dq)) != 0) {
-            if (errno != ESRCH) {
-                PLOG(ERROR) << "Failed to quotactl " << device << " for UID " << uid;
-            }
-        } else {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for UID " << uid << " " << dq.dqb_curspace;
-#endif
-            totalSize = dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForUid(uuidString, uid)) != -1) {
+            totalSize = space;
         }
 
         gid_t audioGid = multiuser_get_uid(userId, AID_MEDIA_AUDIO);
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), audioGid,
-                reinterpret_cast<char*>(&dq)) == 0) {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for GID " << audioGid << " " << dq.dqb_curspace;
-#endif
-            audioSize = dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForGid(uuidString, audioGid)) != -1) {
+            audioSize = space;
         }
         gid_t videoGid = multiuser_get_uid(userId, AID_MEDIA_VIDEO);
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), videoGid,
-                reinterpret_cast<char*>(&dq)) == 0) {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for GID " << videoGid << " " << dq.dqb_curspace;
-#endif
-            videoSize = dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForGid(uuidString, videoGid)) != -1) {
+            videoSize = space;
         }
         gid_t imageGid = multiuser_get_uid(userId, AID_MEDIA_IMAGE);
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), imageGid,
-                reinterpret_cast<char*>(&dq)) == 0) {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for GID " << imageGid << " " << dq.dqb_curspace;
-#endif
-            imageSize = dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForGid(uuidString, imageGid)) != -1) {
+            imageSize = space;
         }
-        if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), AID_MEDIA_OBB,
-                reinterpret_cast<char*>(&dq)) == 0) {
-#if MEASURE_DEBUG
-            LOG(DEBUG) << "quotactl() for GID " << AID_MEDIA_OBB << " " << dq.dqb_curspace;
-#endif
-            obbSize = dq.dqb_curspace;
+        if ((space = GetOccupiedSpaceForGid(uuidString, AID_MEDIA_OBB)) != -1) {
+            obbSize = space;
         }
         ATRACE_END();
 
@@ -1736,7 +1648,7 @@
         memset(&extStats, 0, sizeof(extStats));
         for (auto appId : appIds) {
             if (appId >= AID_APP_START) {
-                collectQuotaStats(device, userId, appId, nullptr, &extStats);
+                collectQuotaStats(uuidString, userId, appId, nullptr, &extStats);
             }
         }
         appSize = extStats.dataSize;
@@ -2524,7 +2436,12 @@
     std::lock_guard<std::recursive_mutex> lock(mMountsLock);
 
     mStorageMounts.clear();
-    mQuotaReverseMounts.clear();
+
+#if !BYPASS_QUOTA
+    if (!InvalidateQuotaMounts()) {
+        return error("Failed to read mounts");
+    }
+#endif
 
     std::ifstream in("/proc/mounts");
     if (!in.is_open()) {
@@ -2545,17 +2462,6 @@
             mStorageMounts[source] = target;
         }
 #endif
-
-#if !BYPASS_QUOTA
-        if (source.compare(0, 11, "/dev/block/") == 0) {
-            struct dqblk dq;
-            if (quotactl(QCMD(Q_GETQUOTA, USRQUOTA), source.c_str(), 0,
-                    reinterpret_cast<char*>(&dq)) == 0) {
-                LOG(DEBUG) << "Found quota mount " << source << " at " << target;
-                mQuotaReverseMounts[target] = source;
-            }
-        }
-#endif
     }
     return ok();
 }
@@ -2573,16 +2479,10 @@
     return StringPrintf("%s/%u", resolved.c_str(), userid);
 }
 
-std::string InstalldNativeService::findQuotaDeviceForUuid(
-        const std::unique_ptr<std::string>& uuid) {
-    std::lock_guard<std::recursive_mutex> lock(mMountsLock);
-    auto path = create_data_path(uuid ? uuid->c_str() : nullptr);
-    return mQuotaReverseMounts[path];
-}
-
 binder::Status InstalldNativeService::isQuotaSupported(
-        const std::unique_ptr<std::string>& volumeUuid, bool* _aidl_return) {
-    *_aidl_return = !findQuotaDeviceForUuid(volumeUuid).empty();
+        const std::unique_ptr<std::string>& uuid, bool* _aidl_return) {
+    auto uuidString = uuid ? *uuid : "";
+    *_aidl_return = IsQuotaSupported(uuidString);
     return ok();
 }
 
diff --git a/cmds/installd/InstalldNativeService.h b/cmds/installd/InstalldNativeService.h
index cebd3f9..367f2c1 100644
--- a/cmds/installd/InstalldNativeService.h
+++ b/cmds/installd/InstalldNativeService.h
@@ -150,14 +150,11 @@
 
     /* Map of all storage mounts from source to target */
     std::unordered_map<std::string, std::string> mStorageMounts;
-    /* Map of all quota mounts from target to source */
-    std::unordered_map<std::string, std::string> mQuotaReverseMounts;
 
     /* Map from UID to cache quota size */
     std::unordered_map<uid_t, int64_t> mCacheQuotas;
 
     std::string findDataMediaPath(const std::unique_ptr<std::string>& uuid, userid_t userid);
-    std::string findQuotaDeviceForUuid(const std::unique_ptr<std::string>& uuid);
 };
 
 }  // namespace installd
diff --git a/cmds/installd/QuotaUtils.cpp b/cmds/installd/QuotaUtils.cpp
new file mode 100644
index 0000000..b238dd3
--- /dev/null
+++ b/cmds/installd/QuotaUtils.cpp
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2018 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 "QuotaUtils.h"
+
+#include <fstream>
+#include <unordered_map>
+
+#include <sys/quota.h>
+
+#include <android-base/logging.h>
+
+#include "utils.h"
+
+namespace android {
+namespace installd {
+
+namespace {
+
+std::recursive_mutex mMountsLock;
+
+/* Map of all quota mounts from target to source */
+std::unordered_map<std::string, std::string> mQuotaReverseMounts;
+
+std::string& FindQuotaDeviceForUuid(const std::string& uuid) {
+    std::lock_guard<std::recursive_mutex> lock(mMountsLock);
+    auto path = create_data_path(uuid.empty() ? nullptr : uuid.c_str());
+    return mQuotaReverseMounts[path];
+}
+
+} // namespace
+
+bool InvalidateQuotaMounts() {
+    std::lock_guard<std::recursive_mutex> lock(mMountsLock);
+
+    mQuotaReverseMounts.clear();
+
+    std::ifstream in("/proc/mounts");
+    if (!in.is_open()) {
+        return false;
+    }
+
+    std::string source;
+    std::string target;
+    std::string ignored;
+    while (!in.eof()) {
+        std::getline(in, source, ' ');
+        std::getline(in, target, ' ');
+        std::getline(in, ignored);
+
+        if (source.compare(0, 11, "/dev/block/") == 0) {
+            struct dqblk dq;
+            if (quotactl(QCMD(Q_GETQUOTA, USRQUOTA), source.c_str(), 0,
+                    reinterpret_cast<char*>(&dq)) == 0) {
+                LOG(DEBUG) << "Found quota mount " << source << " at " << target;
+                mQuotaReverseMounts[target] = source;
+            }
+        }
+    }
+    return true;
+}
+
+bool IsQuotaSupported(const std::string& uuid) {
+    return !FindQuotaDeviceForUuid(uuid).empty();
+}
+
+int64_t GetOccupiedSpaceForUid(const std::string& uuid, uid_t uid) {
+    const std::string device = FindQuotaDeviceForUuid(uuid);
+    if (device == "") {
+        return -1;
+    }
+    struct dqblk dq;
+    if (quotactl(QCMD(Q_GETQUOTA, USRQUOTA), device.c_str(), uid,
+            reinterpret_cast<char*>(&dq)) != 0) {
+        if (errno != ESRCH) {
+            PLOG(ERROR) << "Failed to quotactl " << device << " for UID " << uid;
+        }
+        return -1;
+    } else {
+#if MEASURE_DEBUG
+        LOG(DEBUG) << "quotactl() for UID " << uid << " " << dq.dqb_curspace;
+#endif
+        return dq.dqb_curspace;
+    }
+}
+
+int64_t GetOccupiedSpaceForGid(const std::string& uuid, gid_t gid) {
+    const std::string device = FindQuotaDeviceForUuid(uuid);
+    if (device == "") {
+        return -1;
+    }
+    struct dqblk dq;
+    if (quotactl(QCMD(Q_GETQUOTA, GRPQUOTA), device.c_str(), gid,
+            reinterpret_cast<char*>(&dq)) != 0) {
+        if (errno != ESRCH) {
+            PLOG(ERROR) << "Failed to quotactl " << device << " for GID " << gid;
+        }
+        return -1;
+    } else {
+#if MEASURE_DEBUG
+        LOG(DEBUG) << "quotactl() for GID " << gid << " " << dq.dqb_curspace;
+#endif
+        return dq.dqb_curspace;
+    }
+
+}
+
+}  // namespace installd
+}  // namespace android
diff --git a/cmds/installd/QuotaUtils.h b/cmds/installd/QuotaUtils.h
new file mode 100644
index 0000000..9ad170f
--- /dev/null
+++ b/cmds/installd/QuotaUtils.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 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_INSTALLD_QUOTA_UTILS_H_
+#define ANDROID_INSTALLD_QUOTA_UTILS_H_
+
+#include <memory>
+#include <string>
+
+namespace android {
+namespace installd {
+
+/* Clear and recompute the reverse mounts map */
+bool InvalidateQuotaMounts();
+
+/* Whether quota is supported in the device with the given uuid */
+bool IsQuotaSupported(const std::string& uuid);
+
+/* Get the current occupied space in bytes for a uid or -1 if fails */
+int64_t GetOccupiedSpaceForUid(const std::string& uuid, uid_t uid);
+
+/* Get the current occupied space in bytes for a gid or -1 if fails */
+int64_t GetOccupiedSpaceForGid(const std::string& uuid, gid_t gid);
+
+}  // namespace installd
+}  // namespace android
+
+#endif  // ANDROID_INSTALLD_QUOTA_UTILS_H_