Add f2fs support for private volumes.

When formatting volumes, pass along fsType string which can be "auto"
to let the volume select the best choice.  For now, private volumes
assume that MMC devices (like SD cards) are best off using f2fs when
both kernel support and tools are present, otherwise fall back to
ext4.  Use blkid when mounting to pick the right set of tools.

Move filesystem utility methods into namespaces and place in separate
directory to be more organized.

Bug: 20275581
Change-Id: Id5f82d8672dda2e9f68c35b075f28232b0b55ed4
diff --git a/Android.mk b/Android.mk
index 8912959..d403b96 100644
--- a/Android.mk
+++ b/Android.mk
@@ -8,8 +8,9 @@
 	NetlinkManager.cpp \
 	NetlinkHandler.cpp \
 	Process.cpp \
-	Ext4.cpp \
-	Fat.cpp \
+	fs/Ext4.cpp \
+	fs/F2fs.cpp \
+	fs/Vfat.cpp \
 	Loop.cpp \
 	Devmapper.cpp \
 	ResponseCode.cpp \
diff --git a/CommandListener.cpp b/CommandListener.cpp
index 81318aa..74fe3fc 100644
--- a/CommandListener.cpp
+++ b/CommandListener.cpp
@@ -222,15 +222,16 @@
 
         return sendGenericOkFail(cli, vol->unmount());
 
-    } else if (cmd == "format" && argc > 2) {
-        // format [volId]
+    } else if (cmd == "format" && argc > 3) {
+        // format [volId] [fsType|auto]
         std::string id(argv[2]);
+        std::string fsType(argv[3]);
         auto vol = vm->findVolume(id);
         if (vol == nullptr) {
             return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
         }
 
-        return sendGenericOkFail(cli, vol->format());
+        return sendGenericOkFail(cli, vol->format(fsType));
 
     } else if (cmd == "move_storage" && argc > 3) {
         // move_storage [fromVolId] [toVolId]
diff --git a/Disk.cpp b/Disk.cpp
index 5b5d769..a536dbf 100644
--- a/Disk.cpp
+++ b/Disk.cpp
@@ -136,7 +136,7 @@
         LOG(DEBUG) << "Device just partitioned; silently formatting";
         vol->setSilent(true);
         vol->create();
-        vol->format();
+        vol->format("auto");
         vol->destroy();
         vol->setSilent(false);
     }
@@ -168,7 +168,7 @@
         LOG(DEBUG) << "Device just partitioned; silently formatting";
         vol->setSilent(true);
         vol->create();
-        vol->format();
+        vol->format("auto");
         vol->destroy();
         vol->setSilent(false);
     }
diff --git a/Ext4.h b/Ext4.h
deleted file mode 100644
index 55672af..0000000
--- a/Ext4.h
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright (C) 2012 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 _EXT4_H
-#define _EXT4_H
-
-#include <unistd.h>
-
-class Ext4 {
-public:
-    static int check(const char *fsPath, const char *mountPoint);
-    static int doMount(const char *fsPath, const char *mountPoint, bool ro, bool remount,
-            bool executable);
-    static int format(const char *fsPath, unsigned int numSectors, const char *mountpoint);
-    static int resize(const char *fsPath, unsigned int numSectors);
-};
-
-#endif
diff --git a/Fat.h b/Fat.h
deleted file mode 100644
index 19614d1..0000000
--- a/Fat.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Copyright (C) 2008 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 _FAT_H
-#define _FAT_H
-
-#include <unistd.h>
-
-class Fat {
-public:
-    static int check(const char *fsPath);
-    static int doMount(const char *fsPath, const char *mountPoint,
-                       bool ro, bool remount, bool executable,
-                       int ownerUid, int ownerGid, int permMask,
-                       bool createLost);
-    static int format(const char *fsPath, unsigned int numSectors, bool wipe);
-
-private:
-    static void wipe(const char *fsPath, unsigned int numSectors);
-};
-
-#endif
diff --git a/PrivateVolume.cpp b/PrivateVolume.cpp
index ff2c7b3..a1bbb3b 100644
--- a/PrivateVolume.cpp
+++ b/PrivateVolume.cpp
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-#include "Ext4.h"
+#include "fs/Ext4.h"
+#include "fs/F2fs.h"
 #include "PrivateVolume.h"
 #include "EmulatedVolume.h"
 #include "Utils.h"
@@ -40,6 +41,8 @@
 namespace android {
 namespace vold {
 
+static const unsigned int kMajorBlockMmc = 179;
+
 PrivateVolume::PrivateVolume(dev_t device, const std::string& keyRaw) :
         VolumeBase(Type::kPrivate), mRawDevice(device), mKeyRaw(keyRaw) {
     setId(StringPrintf("private:%u,%u", major(device), minor(device)));
@@ -101,16 +104,36 @@
         return -EIO;
     }
 
-    int res = Ext4::check(mDmDevPath.c_str(), mPath.c_str());
-    if (res == 0 || res == 1) {
-        LOG(DEBUG) << getId() << " passed filesystem check";
-    } else {
-        PLOG(ERROR) << getId() << " failed filesystem check";
-        return -EIO;
-    }
+    if (mFsType == "ext4") {
+        int res = ext4::Check(mDmDevPath, mPath);
+        if (res == 0 || res == 1) {
+            LOG(DEBUG) << getId() << " passed filesystem check";
+        } else {
+            PLOG(ERROR) << getId() << " failed filesystem check";
+            return -EIO;
+        }
 
-    if (Ext4::doMount(mDmDevPath.c_str(), mPath.c_str(), false, false, true)) {
-        PLOG(ERROR) << getId() << " failed to mount";
+        if (ext4::Mount(mDmDevPath, mPath, false, false, true)) {
+            PLOG(ERROR) << getId() << " failed to mount";
+            return -EIO;
+        }
+
+    } else if (mFsType == "f2fs") {
+        int res = f2fs::Check(mDmDevPath);
+        if (res == 0) {
+            LOG(DEBUG) << getId() << " passed filesystem check";
+        } else {
+            PLOG(ERROR) << getId() << " failed filesystem check";
+            return -EIO;
+        }
+
+        if (f2fs::Mount(mDmDevPath, mPath)) {
+            PLOG(ERROR) << getId() << " failed to mount";
+            return -EIO;
+        }
+
+    } else {
+        LOG(ERROR) << getId() << " unsupported filesystem " << mFsType;
         return -EIO;
     }
 
@@ -124,6 +147,8 @@
         return -EIO;
     }
 
+    // TODO: restorecon all the things!
+
     // Create a new emulated volume stacked above us, it will automatically
     // be destroyed during unmount
     std::string mediaPath(mPath + "/media");
@@ -145,11 +170,33 @@
     return OK;
 }
 
-status_t PrivateVolume::doFormat() {
-    // TODO: change mountpoint once we have selinux labels
-    if (Ext4::format(mDmDevPath.c_str(), 0, "/data")) {
-        PLOG(ERROR) << getId() << " failed to format";
-        return -EIO;
+status_t PrivateVolume::doFormat(const std::string& fsType) {
+    std::string resolvedFsType = fsType;
+    if (fsType == "auto") {
+        // For now, assume that all MMC devices are flash-based SD cards, and
+        // give everyone else ext4 because sysfs rotational isn't reliable.
+        if ((major(mRawDevice) == kMajorBlockMmc) && f2fs::IsSupported()) {
+            resolvedFsType = "f2fs";
+        } else {
+            resolvedFsType = "ext4";
+        }
+        LOG(DEBUG) << "Resolved auto to " << resolvedFsType;
+    }
+
+    if (resolvedFsType == "ext4") {
+        // TODO: change reported mountpoint once we have better selinux support
+        if (ext4::Format(mDmDevPath, 0, "/data")) {
+            PLOG(ERROR) << getId() << " failed to format";
+            return -EIO;
+        }
+    } else if (resolvedFsType == "f2fs") {
+        if (f2fs::Format(mDmDevPath)) {
+            PLOG(ERROR) << getId() << " failed to format";
+            return -EIO;
+        }
+    } else {
+        LOG(ERROR) << getId() << " unsupported filesystem " << fsType;
+        return -EINVAL;
     }
 
     return OK;
diff --git a/PrivateVolume.h b/PrivateVolume.h
index bd464e6..95b718d 100644
--- a/PrivateVolume.h
+++ b/PrivateVolume.h
@@ -45,7 +45,7 @@
     status_t doDestroy() override;
     status_t doMount() override;
     status_t doUnmount() override;
-    status_t doFormat() override;
+    status_t doFormat(const std::string& fsType) override;
 
     status_t readMetadata();
 
diff --git a/PublicVolume.cpp b/PublicVolume.cpp
index 2b2c32b..9d6887d 100644
--- a/PublicVolume.cpp
+++ b/PublicVolume.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "Fat.h"
+#include "fs/Vfat.h"
 #include "PublicVolume.h"
 #include "Utils.h"
 #include "VolumeManager.h"
@@ -94,7 +94,7 @@
     // TODO: expand to support mounting other filesystems
     readMetadata();
 
-    if (Fat::check(mDevPath.c_str())) {
+    if (vfat::Check(mDevPath)) {
         LOG(ERROR) << getId() << " failed filesystem check";
         return -EIO;
     }
@@ -119,7 +119,7 @@
         return -errno;
     }
 
-    if (Fat::doMount(mDevPath.c_str(), mRawPath.c_str(), false, false, false,
+    if (vfat::Mount(mDevPath, mRawPath, false, false, false,
             AID_MEDIA_RW, AID_MEDIA_RW, 0007, true)) {
         PLOG(ERROR) << getId() << " failed to mount " << mDevPath;
         return -EIO;
@@ -200,11 +200,20 @@
     return OK;
 }
 
-status_t PublicVolume::doFormat() {
-    if (Fat::format(mDevPath.c_str(), 0, true)) {
-        LOG(ERROR) << getId() << " failed to format";
-        return -errno;
+status_t PublicVolume::doFormat(const std::string& fsType) {
+    if (fsType == "vfat" || fsType == "auto") {
+        if (WipeBlockDevice(mDevPath) != OK) {
+            LOG(WARNING) << getId() << " failed to wipe";
+        }
+        if (vfat::Format(mDevPath, 0)) {
+            LOG(ERROR) << getId() << " failed to format";
+            return -errno;
+        }
+    } else {
+        LOG(ERROR) << "Unsupported filesystem " << fsType;
+        return -EINVAL;
     }
+
     return OK;
 }
 
diff --git a/PublicVolume.h b/PublicVolume.h
index 45313ec..fd400f2 100644
--- a/PublicVolume.h
+++ b/PublicVolume.h
@@ -47,7 +47,7 @@
     status_t doDestroy() override;
     status_t doMount() override;
     status_t doUnmount() override;
-    status_t doFormat() override;
+    status_t doFormat(const std::string& fsType) override;
 
     status_t readMetadata();
     status_t initAsecStage();
diff --git a/Utils.cpp b/Utils.cpp
index 0b8ccfd..e06111a 100644
--- a/Utils.cpp
+++ b/Utils.cpp
@@ -18,6 +18,7 @@
 #include "Utils.h"
 #include "Process.h"
 
+#include <base/file.h>
 #include <base/logging.h>
 #include <base/stringprintf.h>
 #include <cutils/fs.h>
@@ -39,6 +40,7 @@
 #define UMOUNT_NOFOLLOW    0x00000008  /* Don't follow symlink on umount */
 #endif
 
+using android::base::ReadFileToString;
 using android::base::StringPrintf;
 
 namespace android {
@@ -51,6 +53,8 @@
 
 static const char* kBlkidPath = "/system/bin/blkid";
 
+static const char* kProcFilesystems = "/proc/filesystems";
+
 status_t CreateDeviceNode(const std::string& path, dev_t dev) {
     const char* cpath = path.c_str();
     status_t res = 0;
@@ -463,5 +467,47 @@
     }
 }
 
+bool IsFilesystemSupported(const std::string& fsType) {
+    std::string supported;
+    if (!ReadFileToString(kProcFilesystems, &supported)) {
+        PLOG(ERROR) << "Failed to read supported filesystems";
+        return false;
+    }
+    return supported.find(fsType + "\n") != std::string::npos;
+}
+
+status_t WipeBlockDevice(const std::string& path) {
+    status_t res = -1;
+    const char* c_path = path.c_str();
+    unsigned long nr_sec = 0;
+    unsigned long long range[2];
+
+    int fd = TEMP_FAILURE_RETRY(open(c_path, O_RDWR | O_CLOEXEC));
+    if (fd == -1) {
+        PLOG(ERROR) << "Failed to open " << path;
+        goto done;
+    }
+
+    if ((ioctl(fd, BLKGETSIZE, nr_sec)) == -1) {
+        PLOG(ERROR) << "Failed to determine size of " << path;
+        goto done;
+    }
+
+    range[0] = 0;
+    range[1] = (unsigned long long) nr_sec * 512;
+
+    LOG(INFO) << "About to discard " << range[1] << " on " << path;
+    if (ioctl(fd, BLKDISCARD, &range) == 0) {
+        LOG(INFO) << "Discard success on " << path;
+        res = 0;
+    } else {
+        PLOG(ERROR) << "Discard failure on " << path;
+    }
+
+done:
+    close(fd);
+    return res;
+}
+
 }  // namespace vold
 }  // namespace android
diff --git a/Utils.h b/Utils.h
index 6ad87ae..ab151aa 100644
--- a/Utils.h
+++ b/Utils.h
@@ -81,6 +81,11 @@
 uint64_t GetFreeBytes(const std::string& path);
 uint64_t GetTreeBytes(const std::string& path);
 
+bool IsFilesystemSupported(const std::string& fsType);
+
+/* Wipes contents of block device at given path */
+status_t WipeBlockDevice(const std::string& path);
+
 }  // namespace vold
 }  // namespace android
 
diff --git a/VolumeBase.cpp b/VolumeBase.cpp
index ca056a4..05a61ed 100644
--- a/VolumeBase.cpp
+++ b/VolumeBase.cpp
@@ -222,7 +222,7 @@
     return res;
 }
 
-status_t VolumeBase::format() {
+status_t VolumeBase::format(const std::string& fsType) {
     if (mState == State::kMounted) {
         unmount();
     }
@@ -233,12 +233,12 @@
     }
 
     setState(State::kFormatting);
-    status_t res = doFormat();
+    status_t res = doFormat(fsType);
     setState(State::kUnmounted);
     return res;
 }
 
-status_t VolumeBase::doFormat() {
+status_t VolumeBase::doFormat(const std::string& fsType) {
     return -ENOTSUP;
 }
 
diff --git a/VolumeBase.h b/VolumeBase.h
index a9975f8..42b4d65 100644
--- a/VolumeBase.h
+++ b/VolumeBase.h
@@ -97,7 +97,7 @@
     status_t destroy();
     status_t mount();
     status_t unmount();
-    status_t format();
+    status_t format(const std::string& fsType);
 
 protected:
     explicit VolumeBase(Type type);
@@ -106,7 +106,7 @@
     virtual status_t doDestroy();
     virtual status_t doMount() = 0;
     virtual status_t doUnmount() = 0;
-    virtual status_t doFormat();
+    virtual status_t doFormat(const std::string& fsType);
 
     status_t setId(const std::string& id);
     status_t setPath(const std::string& path);
diff --git a/VolumeManager.cpp b/VolumeManager.cpp
index c34f169..9306363 100755
--- a/VolumeManager.cpp
+++ b/VolumeManager.cpp
@@ -51,8 +51,8 @@
 #include "NetlinkManager.h"
 #include "ResponseCode.h"
 #include "Loop.h"
-#include "Ext4.h"
-#include "Fat.h"
+#include "fs/Ext4.h"
+#include "fs/Vfat.h"
 #include "Utils.h"
 #include "Devmapper.h"
 #include "Process.h"
@@ -725,9 +725,9 @@
         }
 
         if (usingExt4) {
-            formatStatus = Ext4::format(dmDevice, numImgSectors, mountPoint);
+            formatStatus = android::vold::ext4::Format(dmDevice, numImgSectors, mountPoint);
         } else {
-            formatStatus = Fat::format(dmDevice, numImgSectors, 0);
+            formatStatus = android::vold::vfat::Format(dmDevice, numImgSectors);
         }
 
         if (formatStatus < 0) {
@@ -754,10 +754,11 @@
 
         int mountStatus;
         if (usingExt4) {
-            mountStatus = Ext4::doMount(dmDevice, mountPoint, false, false, false);
+            mountStatus = android::vold::ext4::Mount(dmDevice, mountPoint,
+                    false, false, false);
         } else {
-            mountStatus = Fat::doMount(dmDevice, mountPoint, false, false, false, ownerUid, 0, 0000,
-                    false);
+            mountStatus = android::vold::vfat::Mount(dmDevice, mountPoint,
+                    false, false, false, ownerUid, 0, 0000, false);
         }
 
         if (mountStatus) {
@@ -916,7 +917,7 @@
      */
     waitForDevMapper(dmDevice);
 
-    if (Ext4::resize(dmDevice, numImgSectors)) {
+    if (android::vold::ext4::Resize(dmDevice, numImgSectors)) {
         SLOGE("Unable to resize %s (%s)", id, strerror(errno));
         if (cleanupDm) {
             Devmapper::destroy(idHash);
@@ -973,9 +974,11 @@
 
     int result = 0;
     if (sb.c_opts & ASEC_SB_C_OPTS_EXT4) {
-        result = Ext4::doMount(loopDevice, mountPoint, true, true, true);
+        result = android::vold::ext4::Mount(loopDevice, mountPoint,
+                true, true, true);
     } else {
-        result = Fat::doMount(loopDevice, mountPoint, true, true, true, 0, 0, 0227, false);
+        result = android::vold::vfat::Mount(loopDevice, mountPoint,
+                true, true, true, 0, 0, 0227, false);
     }
 
     if (result) {
@@ -1039,7 +1042,7 @@
         return 0;
     }
 
-    int ret = Ext4::doMount(loopDevice, mountPoint,
+    int ret = android::vold::ext4::Mount(loopDevice, mountPoint,
             false /* read-only */,
             true  /* remount */,
             false /* executable */);
@@ -1101,7 +1104,7 @@
         result |= -1;
     }
 
-    result |= Ext4::doMount(loopDevice, mountPoint,
+    result |= android::vold::ext4::Mount(loopDevice, mountPoint,
             true /* read-only */,
             true /* remount */,
             true /* execute */);
@@ -1537,9 +1540,11 @@
 
     int result;
     if (sb.c_opts & ASEC_SB_C_OPTS_EXT4) {
-        result = Ext4::doMount(dmDevice, mountPoint, readOnly, false, readOnly);
+        result = android::vold::ext4::Mount(dmDevice, mountPoint,
+                readOnly, false, readOnly);
     } else {
-        result = Fat::doMount(dmDevice, mountPoint, readOnly, false, readOnly, ownerUid, 0, 0222, false);
+        result = android::vold::vfat::Mount(dmDevice, mountPoint,
+                readOnly, false, readOnly, ownerUid, 0, 0222, false);
     }
 
     if (result) {
@@ -1628,8 +1633,8 @@
      */
     waitForDevMapper(dmDevice);
 
-    if (Fat::doMount(dmDevice, mountPoint, true, false, true, 0, ownerGid,
-                     0227, false)) {
+    if (android::vold::vfat::Mount(dmDevice, mountPoint,
+            true, false, true, 0, ownerGid, 0227, false)) {
         SLOGE("Image mount failed (%s)", strerror(errno));
         if (cleanupDm) {
             Devmapper::destroy(idHash);
diff --git a/Ext4.cpp b/fs/Ext4.cpp
similarity index 72%
rename from Ext4.cpp
rename to fs/Ext4.cpp
index a208eb5..3ae4159 100644
--- a/Ext4.cpp
+++ b/fs/Ext4.cpp
@@ -50,16 +50,26 @@
 
 using android::base::StringPrintf;
 
+namespace android {
+namespace vold {
+namespace ext4 {
+
 static const char* kResizefsPath = "/system/bin/resize2fs";
 static const char* kMkfsPath = "/system/bin/make_ext4fs";
 static const char* kFsckPath = "/system/bin/e2fsck";
 
-int Ext4::check(const char *fsPath, const char *mountPoint) {
+bool IsSupported() {
+    return access(kMkfsPath, X_OK) == 0
+            && access(kFsckPath, X_OK) == 0
+            && IsFilesystemSupported("ext4");
+}
+
+status_t Check(const std::string& source, const std::string& target) {
     // The following is shamelessly borrowed from fs_mgr.c, so it should be
     // kept in sync with any changes over there.
 
-    char* blk_device = (char*) fsPath;
-    char* target = (char*) mountPoint;
+    const char* c_source = source.c_str();
+    const char* c_target = target.c_str();
 
     int status;
     int ret;
@@ -79,17 +89,17 @@
      * filesytsem due to an error, e2fsck is still run to do a full check
      * fix the filesystem.
      */
-    ret = mount(blk_device, target, "ext4", tmpmnt_flags, tmpmnt_opts);
+    ret = mount(c_source, c_target, "ext4", tmpmnt_flags, tmpmnt_opts);
     if (!ret) {
         int i;
         for (i = 0; i < 5; i++) {
             // Try to umount 5 times before continuing on.
             // Should we try rebooting if all attempts fail?
-            int result = umount(target);
+            int result = umount(c_target);
             if (result == 0) {
                 break;
             }
-            ALOGW("%s(): umount(%s)=%d: %s\n", __func__, target, result, strerror(errno));
+            ALOGW("%s(): umount(%s)=%d: %s\n", __func__, c_target, result, strerror(errno));
             sleep(1);
         }
     }
@@ -100,61 +110,65 @@
      */
     if (access(kFsckPath, X_OK)) {
         ALOGD("Not running %s on %s (executable not in system image)\n",
-                kFsckPath, blk_device);
+                kFsckPath, c_source);
     } else {
-        ALOGD("Running %s on %s\n", kFsckPath, blk_device);
+        ALOGD("Running %s on %s\n", kFsckPath, c_source);
 
         std::vector<std::string> cmd;
         cmd.push_back(kFsckPath);
         cmd.push_back("-y");
-        cmd.push_back(blk_device);
+        cmd.push_back(c_source);
 
-        // Ext4 devices are currently always trusted
-        return android::vold::ForkExecvp(cmd, android::vold::sFsckContext);
+        // ext4 devices are currently always trusted
+        return ForkExecvp(cmd, sFsckContext);
     }
 
     return 0;
 }
 
-int Ext4::doMount(const char *fsPath, const char *mountPoint, bool ro, bool remount,
-        bool executable) {
+status_t Mount(const std::string& source, const std::string& target, bool ro,
+        bool remount, bool executable) {
     int rc;
     unsigned long flags;
 
+    const char* c_source = source.c_str();
+    const char* c_target = target.c_str();
+
     flags = MS_NOATIME | MS_NODEV | MS_NOSUID | MS_DIRSYNC;
 
     flags |= (executable ? 0 : MS_NOEXEC);
     flags |= (ro ? MS_RDONLY : 0);
     flags |= (remount ? MS_REMOUNT : 0);
 
-    rc = mount(fsPath, mountPoint, "ext4", flags, NULL);
+    rc = mount(c_source, c_target, "ext4", flags, NULL);
 
     if (rc && errno == EROFS) {
-        SLOGE("%s appears to be a read only filesystem - retrying mount RO", fsPath);
+        SLOGE("%s appears to be a read only filesystem - retrying mount RO", c_source);
         flags |= MS_RDONLY;
-        rc = mount(fsPath, mountPoint, "ext4", flags, NULL);
+        rc = mount(c_source, c_target, "ext4", flags, NULL);
     }
 
     return rc;
 }
 
-int Ext4::resize(const char *fspath, unsigned int numSectors) {
+status_t Resize(const std::string& source, unsigned int numSectors) {
     std::vector<std::string> cmd;
     cmd.push_back(kResizefsPath);
     cmd.push_back("-f");
-    cmd.push_back(fspath);
+    cmd.push_back(source);
     cmd.push_back(StringPrintf("%u", numSectors));
 
-    return android::vold::ForkExecvp(cmd);
+    return ForkExecvp(cmd);
 }
 
-int Ext4::format(const char *fsPath, unsigned int numSectors, const char *mountpoint) {
+status_t Format(const std::string& source, unsigned int numSectors,
+        const std::string& target) {
     std::vector<std::string> cmd;
     cmd.push_back(kMkfsPath);
     cmd.push_back("-J");
 
     cmd.push_back("-a");
-    cmd.push_back(mountpoint);
+    cmd.push_back(target);
 
     if (numSectors) {
         cmd.push_back("-l");
@@ -163,7 +177,11 @@
 
     // Always generate a real UUID
     cmd.push_back("-u");
-    cmd.push_back(fsPath);
+    cmd.push_back(source);
 
-    return android::vold::ForkExecvp(cmd);
+    return ForkExecvp(cmd);
 }
+
+}  // namespace ext4
+}  // namespace vold
+}  // namespace android
diff --git a/fs/Ext4.h b/fs/Ext4.h
new file mode 100644
index 0000000..a5efa74
--- /dev/null
+++ b/fs/Ext4.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2012 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_EXT4_H
+#define ANDROID_VOLD_EXT4_H
+
+#include <utils/Errors.h>
+
+#include <string>
+
+namespace android {
+namespace vold {
+namespace ext4 {
+
+bool IsSupported();
+
+status_t Check(const std::string& source, const std::string& target);
+status_t Mount(const std::string& source, const std::string& target, bool ro,
+        bool remount, bool executable);
+status_t Format(const std::string& source, unsigned int numSectors,
+        const std::string& target);
+status_t Resize(const std::string& source, unsigned int numSectors);
+
+}  // namespace ext4
+}  // namespace vold
+}  // namespace android
+
+#endif
diff --git a/fs/F2fs.cpp b/fs/F2fs.cpp
new file mode 100644
index 0000000..b947822
--- /dev/null
+++ b/fs/F2fs.cpp
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2015 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 "F2fs.h"
+#include "Utils.h"
+
+#include <base/logging.h>
+#include <base/stringprintf.h>
+
+#include <vector>
+#include <string>
+
+#include <sys/mount.h>
+
+using android::base::StringPrintf;
+
+namespace android {
+namespace vold {
+namespace f2fs {
+
+static const char* kMkfsPath = "/system/bin/make_f2fs";
+static const char* kFsckPath = "/system/bin/fsck.f2fs";
+
+bool IsSupported() {
+    return access(kMkfsPath, X_OK) == 0
+            && access(kFsckPath, X_OK) == 0
+            && IsFilesystemSupported("f2fs");
+}
+
+status_t Check(const std::string& source) {
+    std::vector<std::string> cmd;
+    cmd.push_back(kFsckPath);
+    cmd.push_back("-f");
+    cmd.push_back(source);
+
+    // f2fs devices are currently always trusted
+    return ForkExecvp(cmd, sFsckContext);
+}
+
+status_t Mount(const std::string& source, const std::string& target) {
+    const char* c_source = source.c_str();
+    const char* c_target = target.c_str();
+    unsigned long flags = MS_NOATIME | MS_NODEV | MS_NOSUID | MS_DIRSYNC;
+
+    int res = mount(c_source, c_target, "f2fs", flags, NULL);
+    if (res != 0) {
+        PLOG(ERROR) << "Failed to mount " << source;
+        if (errno == EROFS) {
+            res = mount(c_source, c_target, "f2fs", flags | MS_RDONLY, NULL);
+            if (res != 0) {
+                PLOG(ERROR) << "Failed to mount read-only " << source;
+            }
+        }
+    }
+
+    return res;
+}
+
+status_t Format(const std::string& source) {
+    std::vector<std::string> cmd;
+    cmd.push_back(kMkfsPath);
+    cmd.push_back(source);
+
+    return ForkExecvp(cmd);
+}
+
+}  // namespace f2fs
+}  // namespace vold
+}  // namespace android
diff --git a/fs/F2fs.h b/fs/F2fs.h
new file mode 100644
index 0000000..f710212
--- /dev/null
+++ b/fs/F2fs.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2015 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_F2FS_H
+#define ANDROID_VOLD_F2FS_H
+
+#include <utils/Errors.h>
+
+#include <string>
+
+namespace android {
+namespace vold {
+namespace f2fs {
+
+bool IsSupported();
+
+status_t Check(const std::string& source);
+status_t Mount(const std::string& source, const std::string& target);
+status_t Format(const std::string& source);
+
+}  // namespace f2fs
+}  // namespace vold
+}  // namespace android
+
+#endif
diff --git a/Fat.cpp b/fs/Vfat.cpp
similarity index 73%
rename from Fat.cpp
rename to fs/Vfat.cpp
index 873088d..faff763 100644
--- a/Fat.cpp
+++ b/fs/Vfat.cpp
@@ -45,16 +45,26 @@
 
 #include <logwrap/logwrap.h>
 
-#include "Fat.h"
+#include "Vfat.h"
 #include "Utils.h"
 #include "VoldUtil.h"
 
 using android::base::StringPrintf;
 
+namespace android {
+namespace vold {
+namespace vfat {
+
 static const char* kMkfsPath = "/system/bin/newfs_msdos";
 static const char* kFsckPath = "/system/bin/fsck_msdos";
 
-int Fat::check(const char *fsPath) {
+bool IsSupported() {
+    return access(kMkfsPath, X_OK) == 0
+            && access(kFsckPath, X_OK) == 0
+            && IsFilesystemSupported("vfat");
+}
+
+status_t Check(const std::string& source) {
     if (access(kFsckPath, X_OK)) {
         SLOGW("Skipping fs checks\n");
         return 0;
@@ -67,10 +77,10 @@
         cmd.push_back(kFsckPath);
         cmd.push_back("-p");
         cmd.push_back("-f");
-        cmd.push_back(fsPath);
+        cmd.push_back(source);
 
         // Fat devices are currently always untrusted
-        rc = android::vold::ForkExecvp(cmd, android::vold::sFsckUntrustedContext);
+        rc = ForkExecvp(cmd, sFsckUntrustedContext);
 
         if (rc < 0) {
             SLOGE("Filesystem check failed due to logwrap error");
@@ -108,13 +118,16 @@
     return 0;
 }
 
-int Fat::doMount(const char *fsPath, const char *mountPoint,
-                 bool ro, bool remount, bool executable,
-                 int ownerUid, int ownerGid, int permMask, bool createLost) {
+status_t Mount(const std::string& source, const std::string& target, bool ro,
+        bool remount, bool executable, int ownerUid, int ownerGid, int permMask,
+        bool createLost) {
     int rc;
     unsigned long flags;
     char mountData[255];
 
+    const char* c_source = source.c_str();
+    const char* c_target = target.c_str();
+
     flags = MS_NODEV | MS_NOSUID | MS_DIRSYNC;
 
     flags |= (executable ? 0 : MS_NOEXEC);
@@ -139,17 +152,17 @@
             "utf8,uid=%d,gid=%d,fmask=%o,dmask=%o,shortname=mixed",
             ownerUid, ownerGid, permMask, permMask);
 
-    rc = mount(fsPath, mountPoint, "vfat", flags, mountData);
+    rc = mount(c_source, c_target, "vfat", flags, mountData);
 
     if (rc && errno == EROFS) {
-        SLOGE("%s appears to be a read only filesystem - retrying mount RO", fsPath);
+        SLOGE("%s appears to be a read only filesystem - retrying mount RO", c_source);
         flags |= MS_RDONLY;
-        rc = mount(fsPath, mountPoint, "vfat", flags, mountData);
+        rc = mount(c_source, c_target, "vfat", flags, mountData);
     }
 
     if (rc == 0 && createLost) {
         char *lost_path;
-        asprintf(&lost_path, "%s/LOST.DIR", mountPoint);
+        asprintf(&lost_path, "%s/LOST.DIR", c_target);
         if (access(lost_path, F_OK)) {
             /*
              * Create a LOST.DIR in the root so we have somewhere to put
@@ -165,11 +178,7 @@
     return rc;
 }
 
-int Fat::format(const char *fsPath, unsigned int numSectors, bool wipe) {
-    if (wipe) {
-        Fat::wipe(fsPath, numSectors);
-    }
-
+status_t Format(const std::string& source, unsigned int numSectors) {
     std::vector<std::string> cmd;
     cmd.push_back(kMkfsPath);
     cmd.push_back("-F");
@@ -185,9 +194,9 @@
         cmd.push_back(StringPrintf("%u", numSectors));
     }
 
-    cmd.push_back(fsPath);
+    cmd.push_back(source);
 
-    int rc = android::vold::ForkExecvp(cmd);
+    int rc = ForkExecvp(cmd);
     if (rc < 0) {
         SLOGE("Filesystem format failed due to logwrap error");
         errno = EIO;
@@ -205,36 +214,6 @@
     return 0;
 }
 
-void Fat::wipe(const char *fsPath, unsigned int numSectors) {
-    unsigned long long range[2];
-
-    int fd = open(fsPath, O_RDWR | O_CLOEXEC);
-    if (fd == -1) {
-        SLOGE("Fat wipe failed to open device %s", fsPath);
-        return;
-    }
-
-    if (numSectors == 0) {
-        unsigned long nr_sec;
-        get_blkdev_size(fd, &nr_sec);
-        if (nr_sec > UINT32_MAX) {
-            SLOGE("Too many sectors for FAT: %ld", nr_sec);
-            close(fd);
-            return;
-        }
-        numSectors = nr_sec;
-    }
-    if (numSectors == 0) {
-        SLOGE("Fat wipe failed to determine size of %s", fsPath);
-        close(fd);
-        return;
-    }
-    range[0] = 0;
-    range[1] = (unsigned long long)numSectors * 512;
-    if (ioctl(fd, BLKDISCARD, &range) < 0) {
-        SLOGE("Fat wipe failed to discard blocks on %s", fsPath);
-    } else {
-        SLOGI("Fat wipe %d sectors on %s succeeded", numSectors, fsPath);
-    }
-    close(fd);
-}
+}  // namespace vfat
+}  // namespace vold
+}  // namespace android
diff --git a/fs/Vfat.h b/fs/Vfat.h
new file mode 100644
index 0000000..306c7db
--- /dev/null
+++ b/fs/Vfat.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2008 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_VFAT_H
+#define ANDROID_VOLD_VFAT_H
+
+#include <utils/Errors.h>
+
+#include <string>
+
+namespace android {
+namespace vold {
+namespace vfat {
+
+bool IsSupported();
+
+status_t Check(const std::string& source);
+status_t Mount(const std::string& source, const std::string& target, bool ro,
+        bool remount, bool executable, int ownerUid, int ownerGid, int permMask,
+        bool createLost);
+status_t Format(const std::string& source, unsigned int numSectors);
+
+}  // namespace vfat
+}  // namespace vold
+}  // namespace android
+
+#endif
diff --git a/main.cpp b/main.cpp
index 290093f..abdff9f 100644
--- a/main.cpp
+++ b/main.cpp
@@ -55,6 +55,11 @@
 
     LOG(INFO) << "Vold 3.0 (the awakening) firing up";
 
+    LOG(VERBOSE) << "Detected support for:"
+            << (android::vold::IsFilesystemSupported("ext4") ? " ext4" : "")
+            << (android::vold::IsFilesystemSupported("f2fs") ? " f2fs" : "")
+            << (android::vold::IsFilesystemSupported("vfat") ? " vfat" : "");
+
     VolumeManager *vm;
     CommandListener *cl;
     CryptCommandListener *ccl;