diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index f8f7eb3..25df451 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -502,9 +502,8 @@
 
 static bool UnzipToMemory(ZipArchiveHandle zip, const std::string& entry_name,
                           std::vector<char>* out) {
-    ZipString zip_entry_name(entry_name.c_str());
     ZipEntry zip_entry;
-    if (FindEntry(zip, zip_entry_name, &zip_entry) != 0) {
+    if (FindEntry(zip, entry_name, &zip_entry) != 0) {
         fprintf(stderr, "archive does not contain '%s'\n", entry_name.c_str());
         return false;
     }
@@ -614,9 +613,8 @@
 static int unzip_to_file(ZipArchiveHandle zip, const char* entry_name) {
     unique_fd fd(make_temporary_fd(entry_name));
 
-    ZipString zip_entry_name(entry_name);
     ZipEntry zip_entry;
-    if (FindEntry(zip, zip_entry_name, &zip_entry) != 0) {
+    if (FindEntry(zip, entry_name, &zip_entry) != 0) {
         fprintf(stderr, "archive does not contain '%s'\n", entry_name);
         errno = ENOENT;
         return -1;
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index c1aafda..6f24fe1 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -1610,38 +1610,6 @@
     return ret;
 }
 
-bool fs_mgr_load_verity_state(int* mode) {
-    /* return the default mode, unless any of the verified partitions are in
-     * logging mode, in which case return that */
-    *mode = VERITY_MODE_DEFAULT;
-
-    Fstab fstab;
-    if (!ReadDefaultFstab(&fstab)) {
-        LERROR << "Failed to read default fstab";
-        return false;
-    }
-
-    for (const auto& entry : fstab) {
-        if (entry.fs_mgr_flags.avb) {
-            *mode = VERITY_MODE_RESTART;  // avb only supports restart mode.
-            break;
-        } else if (!entry.fs_mgr_flags.verify) {
-            continue;
-        }
-
-        int current;
-        if (load_verity_state(entry, &current) < 0) {
-            continue;
-        }
-        if (current != VERITY_MODE_DEFAULT) {
-            *mode = current;
-            break;
-        }
-    }
-
-    return true;
-}
-
 bool fs_mgr_is_verity_enabled(const FstabEntry& entry) {
     if (!entry.fs_mgr_flags.verify && !entry.fs_mgr_flags.avb) {
         return false;
diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index da049ef..78455d4 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -261,10 +261,6 @@
                     LWARNING << "Warning: zramsize= flag malformed: " << arg;
                 }
             }
-        } else if (StartsWith(flag, "verify=")) {
-            // If the verify flag is followed by an = and the location for the verity state.
-            entry->fs_mgr_flags.verify = true;
-            entry->verity_loc = arg;
         } else if (StartsWith(flag, "forceencrypt=")) {
             // The forceencrypt flag is followed by an = and the location of the keys.
             entry->fs_mgr_flags.force_crypt = true;
diff --git a/fs_mgr/fs_mgr_priv.h b/fs_mgr/fs_mgr_priv.h
index 70abf5b..c36fd3d 100644
--- a/fs_mgr/fs_mgr_priv.h
+++ b/fs_mgr/fs_mgr_priv.h
@@ -99,7 +99,6 @@
 bool fs_mgr_is_device_unlocked();
 const std::string& get_android_dt_dir();
 bool is_dt_compatible();
-int load_verity_state(const android::fs_mgr::FstabEntry& entry, int* mode);
 
 bool fs_mgr_is_ext4(const std::string& blk_device);
 bool fs_mgr_is_f2fs(const std::string& blk_device);
diff --git a/fs_mgr/fs_mgr_verity.cpp b/fs_mgr/fs_mgr_verity.cpp
index 3f09157..1deb1ac 100644
--- a/fs_mgr/fs_mgr_verity.cpp
+++ b/fs_mgr/fs_mgr_verity.cpp
@@ -275,248 +275,6 @@
     return 0;
 }
 
-static int check_verity_restart(const char *fname)
-{
-    char buffer[VERITY_KMSG_BUFSIZE + 1];
-    int fd;
-    int rc = 0;
-    ssize_t size;
-    struct stat s;
-
-    fd = TEMP_FAILURE_RETRY(open(fname, O_RDONLY | O_CLOEXEC));
-
-    if (fd == -1) {
-        if (errno != ENOENT) {
-            PERROR << "Failed to open " << fname;
-        }
-        goto out;
-    }
-
-    if (fstat(fd, &s) == -1) {
-        PERROR << "Failed to fstat " << fname;
-        goto out;
-    }
-
-    size = VERITY_KMSG_BUFSIZE;
-
-    if (size > s.st_size) {
-        size = s.st_size;
-    }
-
-    if (lseek(fd, s.st_size - size, SEEK_SET) == -1) {
-        PERROR << "Failed to lseek " << (intmax_t)(s.st_size - size) << " " << fname;
-        goto out;
-    }
-
-    if (!android::base::ReadFully(fd, buffer, size)) {
-        PERROR << "Failed to read " << size << " bytes from " << fname;
-        goto out;
-    }
-
-    buffer[size] = '\0';
-
-    if (strstr(buffer, VERITY_KMSG_RESTART) != NULL) {
-        rc = 1;
-    }
-
-out:
-    if (fd != -1) {
-        close(fd);
-    }
-
-    return rc;
-}
-
-static int was_verity_restart()
-{
-    static const char* files[] = {
-        // clang-format off
-        "/sys/fs/pstore/console-ramoops-0",
-        "/sys/fs/pstore/console-ramoops",
-        "/proc/last_kmsg",
-        NULL
-        // clang-format on
-    };
-    int i;
-
-    for (i = 0; files[i]; ++i) {
-        if (check_verity_restart(files[i])) {
-            return 1;
-        }
-    }
-
-    return 0;
-}
-
-static int metadata_add(FILE *fp, long start, const char *tag,
-        unsigned int length, off64_t *offset)
-{
-    if (fseek(fp, start, SEEK_SET) < 0 ||
-        fprintf(fp, "%s %u\n", tag, length) < 0) {
-        return -1;
-    }
-
-    *offset = ftell(fp);
-
-    if (fseek(fp, length, SEEK_CUR) < 0 ||
-        fprintf(fp, METADATA_EOD " 0\n") < 0) {
-        return -1;
-    }
-
-    return 0;
-}
-
-static int metadata_find(const char *fname, const char *stag,
-        unsigned int slength, off64_t *offset)
-{
-    char tag[METADATA_TAG_MAX_LENGTH + 1];
-    int rc = -1;
-    int n;
-    long start = 0x4000; /* skip cryptfs metadata area */
-    uint32_t magic;
-    unsigned int length = 0;
-
-    if (!fname) {
-        return -1;
-    }
-
-    auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(fname, "re+"), fclose};
-
-    if (!fp) {
-        PERROR << "Failed to open " << fname;
-        return -1;
-    }
-
-    /* check magic */
-    if (fseek(fp.get(), start, SEEK_SET) < 0 || fread(&magic, sizeof(magic), 1, fp.get()) != 1) {
-        PERROR << "Failed to read magic from " << fname;
-        return -1;
-    }
-
-    if (magic != METADATA_MAGIC) {
-        magic = METADATA_MAGIC;
-
-        if (fseek(fp.get(), start, SEEK_SET) < 0 ||
-            fwrite(&magic, sizeof(magic), 1, fp.get()) != 1) {
-            PERROR << "Failed to write magic to " << fname;
-            return -1;
-        }
-
-        rc = metadata_add(fp.get(), start + sizeof(magic), stag, slength, offset);
-        if (rc < 0) {
-            PERROR << "Failed to add metadata to " << fname;
-        }
-
-        return rc;
-    }
-
-    start += sizeof(magic);
-
-    while (1) {
-        n = fscanf(fp.get(), "%" STRINGIFY(METADATA_TAG_MAX_LENGTH) "s %u\n", tag, &length);
-
-        if (n == 2 && strcmp(tag, METADATA_EOD)) {
-            /* found a tag */
-            start = ftell(fp.get());
-
-            if (!strcmp(tag, stag) && length == slength) {
-                *offset = start;
-                return 0;
-            }
-
-            start += length;
-
-            if (fseek(fp.get(), length, SEEK_CUR) < 0) {
-                PERROR << "Failed to seek " << fname;
-                return -1;
-            }
-        } else {
-            rc = metadata_add(fp.get(), start, stag, slength, offset);
-            if (rc < 0) {
-                PERROR << "Failed to write metadata to " << fname;
-            }
-            return rc;
-        }
-    }
-}
-
-static int write_verity_state(const char *fname, off64_t offset, int32_t mode)
-{
-    int fd;
-    int rc = -1;
-    struct verity_state s = { VERITY_STATE_HEADER, VERITY_STATE_VERSION, mode };
-
-    fd = TEMP_FAILURE_RETRY(open(fname, O_WRONLY | O_SYNC | O_CLOEXEC));
-
-    if (fd == -1) {
-        PERROR << "Failed to open " << fname;
-        goto out;
-    }
-
-    if (TEMP_FAILURE_RETRY(pwrite64(fd, &s, sizeof(s), offset)) != sizeof(s)) {
-        PERROR << "Failed to write " << sizeof(s) << " bytes to " << fname
-               << " to offset " << offset;
-        goto out;
-    }
-
-    rc = 0;
-
-out:
-    if (fd != -1) {
-        close(fd);
-    }
-
-    return rc;
-}
-
-static int read_verity_state(const char *fname, off64_t offset, int *mode)
-{
-    int fd = -1;
-    int rc = -1;
-    struct verity_state s;
-
-    fd = TEMP_FAILURE_RETRY(open(fname, O_RDONLY | O_CLOEXEC));
-
-    if (fd == -1) {
-        PERROR << "Failed to open " << fname;
-        goto out;
-    }
-
-    if (TEMP_FAILURE_RETRY(pread64(fd, &s, sizeof(s), offset)) != sizeof(s)) {
-        PERROR << "Failed to read " <<  sizeof(s) << " bytes from " << fname
-               << " offset " << offset;
-        goto out;
-    }
-
-    if (s.header != VERITY_STATE_HEADER) {
-        /* space allocated, but no state written. write default state */
-        *mode = VERITY_MODE_DEFAULT;
-        rc = write_verity_state(fname, offset, *mode);
-        goto out;
-    }
-
-    if (s.version != VERITY_STATE_VERSION) {
-        LERROR << "Unsupported verity state version (" << s.version << ")";
-        goto out;
-    }
-
-    if (s.mode < VERITY_MODE_EIO ||
-        s.mode > VERITY_MODE_LAST) {
-        LERROR << "Unsupported verity mode (" << s.mode << ")";
-        goto out;
-    }
-
-    *mode = s.mode;
-    rc = 0;
-
-out:
-    if (fd != -1) {
-        close(fd);
-    }
-
-    return rc;
-}
-
 static int read_partition(const char *path, uint64_t size)
 {
     char buf[READ_BUF_SIZE];
@@ -540,119 +298,23 @@
     return 0;
 }
 
-static int compare_last_signature(const FstabEntry& entry, int* match) {
-    char tag[METADATA_TAG_MAX_LENGTH + 1];
-    int fd = -1;
-    int rc = -1;
-    off64_t offset = 0;
-    struct fec_handle *f = NULL;
-    struct fec_verity_metadata verity;
-    uint8_t curr[SHA256_DIGEST_LENGTH];
-    uint8_t prev[SHA256_DIGEST_LENGTH];
-
-    *match = 1;
-
-    if (fec_open(&f, entry.blk_device.c_str(), O_RDONLY, FEC_VERITY_DISABLE, FEC_DEFAULT_ROOTS) ==
-        -1) {
-        PERROR << "Failed to open '" << entry.blk_device << "'";
-        return rc;
-    }
-
-    // read verity metadata
-    if (fec_verity_get_metadata(f, &verity) == -1) {
-        PERROR << "Failed to get verity metadata '" << entry.blk_device << "'";
-        goto out;
-    }
-
-    SHA256(verity.signature, sizeof(verity.signature), curr);
-
-    if (snprintf(tag, sizeof(tag), VERITY_LASTSIG_TAG "_%s", basename(entry.mount_point.c_str())) >=
-        (int)sizeof(tag)) {
-        LERROR << "Metadata tag name too long for " << entry.mount_point;
-        goto out;
-    }
-
-    if (metadata_find(entry.verity_loc.c_str(), tag, SHA256_DIGEST_LENGTH, &offset) < 0) {
-        goto out;
-    }
-
-    fd = TEMP_FAILURE_RETRY(open(entry.verity_loc.c_str(), O_RDWR | O_SYNC | O_CLOEXEC));
-
-    if (fd == -1) {
-        PERROR << "Failed to open " << entry.verity_loc;
-        goto out;
-    }
-
-    if (TEMP_FAILURE_RETRY(pread64(fd, prev, sizeof(prev), offset)) != sizeof(prev)) {
-        PERROR << "Failed to read " << sizeof(prev) << " bytes from " << entry.verity_loc
-               << " offset " << offset;
-        goto out;
-    }
-
-    *match = !memcmp(curr, prev, SHA256_DIGEST_LENGTH);
-
-    if (!*match) {
-        /* update current signature hash */
-        if (TEMP_FAILURE_RETRY(pwrite64(fd, curr, sizeof(curr),
-                offset)) != sizeof(curr)) {
-            PERROR << "Failed to write " << sizeof(curr) << " bytes to " << entry.verity_loc
-                   << " offset " << offset;
-            goto out;
-        }
-    }
-
-    rc = 0;
-
-out:
-    fec_close(f);
-    return rc;
-}
-
-static int get_verity_state_offset(const FstabEntry& entry, off64_t* offset) {
-    char tag[METADATA_TAG_MAX_LENGTH + 1];
-
-    if (snprintf(tag, sizeof(tag), VERITY_STATE_TAG "_%s", basename(entry.mount_point.c_str())) >=
-        (int)sizeof(tag)) {
-        LERROR << "Metadata tag name too long for " << entry.mount_point;
-        return -1;
-    }
-
-    return metadata_find(entry.verity_loc.c_str(), tag, sizeof(struct verity_state), offset);
-}
-
-int load_verity_state(const FstabEntry& entry, int* mode) {
+bool fs_mgr_load_verity_state(int* mode) {
     // unless otherwise specified, use EIO mode.
     *mode = VERITY_MODE_EIO;
 
-    // use the kernel parameter if set.
-    std::string veritymode;
-    if (fs_mgr_get_boot_config("veritymode", &veritymode)) {
-        if (veritymode == "enforcing") {
-            *mode = VERITY_MODE_DEFAULT;
-        }
-        return 0;
+    // The bootloader communicates verity mode via the kernel commandline
+    std::string verity_mode;
+    if (!fs_mgr_get_boot_config("veritymode", &verity_mode)) {
+        return false;
     }
 
-    off64_t offset = 0;
-    if (get_verity_state_offset(entry, &offset) < 0) {
-        /* fall back to stateless behavior */
-        return 0;
-    }
-
-    if (was_verity_restart()) {
-        /* device was restarted after dm-verity detected a corrupted
-         * block, so use EIO mode */
-        return write_verity_state(entry.verity_loc.c_str(), offset, *mode);
-    }
-
-    int match = 0;
-    if (!compare_last_signature(entry, &match) && !match) {
-        /* partition has been reflashed, reset dm-verity state */
+    if (verity_mode == "enforcing") {
         *mode = VERITY_MODE_DEFAULT;
-        return write_verity_state(entry.verity_loc.c_str(), offset, *mode);
+    } else if (verity_mode == "logging") {
+        *mode = VERITY_MODE_LOGGING;
     }
 
-    return read_verity_state(entry.verity_loc.c_str(), offset, mode);
+    return true;
 }
 
 // Update the verity table using the actual block device path.
@@ -759,7 +421,7 @@
 
     params.ecc_dev = entry->blk_device.c_str();
 
-    if (load_verity_state(*entry, &params.mode) < 0) {
+    if (!fs_mgr_load_verity_state(&params.mode)) {
         /* if accessing or updating the state failed, switch to the default
          * safe mode. This makes sure the device won't end up in an endless
          * restart loop, and no corrupted data will be exposed to userspace
diff --git a/fs_mgr/include_fstab/fstab/fstab.h b/fs_mgr/include_fstab/fstab/fstab.h
index d7afed6..c7193ab 100644
--- a/fs_mgr/include_fstab/fstab/fstab.h
+++ b/fs_mgr/include_fstab/fstab/fstab.h
@@ -38,7 +38,6 @@
     std::string fs_options;
     std::string key_loc;
     std::string key_dir;
-    std::string verity_loc;
     off64_t length = 0;
     std::string label;
     int partnum = -1;
diff --git a/fs_mgr/libdm/dm.cpp b/fs_mgr/libdm/dm.cpp
index a4614d0..c2917a4 100644
--- a/fs_mgr/libdm/dm.cpp
+++ b/fs_mgr/libdm/dm.cpp
@@ -210,6 +210,20 @@
     return true;
 }
 
+bool DeviceMapper::GetTargetByName(const std::string& name, DmTargetTypeInfo* info) {
+    std::vector<DmTargetTypeInfo> targets;
+    if (!GetAvailableTargets(&targets)) {
+        return false;
+    }
+    for (const auto& target : targets) {
+        if (target.name() == name) {
+            if (info) *info = target;
+            return true;
+        }
+    }
+    return false;
+}
+
 bool DeviceMapper::GetAvailableDevices(std::vector<DmBlockDevice>* devices) {
     devices->clear();
 
diff --git a/fs_mgr/libdm/dm_target.cpp b/fs_mgr/libdm/dm_target.cpp
index cb33eea..f440e6d 100644
--- a/fs_mgr/libdm/dm_target.cpp
+++ b/fs_mgr/libdm/dm_target.cpp
@@ -18,6 +18,7 @@
 
 #include <android-base/logging.h>
 #include <android-base/macros.h>
+#include <android-base/parseint.h>
 #include <android-base/strings.h>
 
 #include <libdm/dm.h>
@@ -115,5 +116,82 @@
     return keyid_ + " " + block_device_;
 }
 
+std::string DmTargetSnapshot::name() const {
+    if (mode_ == SnapshotStorageMode::Merge) {
+        return "snapshot-merge";
+    }
+    return "snapshot";
+}
+
+std::string DmTargetSnapshot::GetParameterString() const {
+    std::string mode;
+    switch (mode_) {
+        case SnapshotStorageMode::Persistent:
+        case SnapshotStorageMode::Merge:
+            // Note: "O" lets us query for overflow in the status message. This
+            // is only supported on kernels 4.4+. On earlier kernels, an overflow
+            // will be reported as "Invalid" in the status string.
+            mode = "P";
+            if (ReportsOverflow(name())) {
+                mode += "O";
+            }
+            break;
+        case SnapshotStorageMode::Transient:
+            mode = "N";
+            break;
+        default:
+            LOG(ERROR) << "DmTargetSnapshot unknown mode";
+            break;
+    }
+    return base_device_ + " " + cow_device_ + " " + mode + " " + std::to_string(chunk_size_);
+}
+
+bool DmTargetSnapshot::ReportsOverflow(const std::string& target_type) {
+    DeviceMapper& dm = DeviceMapper::Instance();
+    DmTargetTypeInfo info;
+    if (!dm.GetTargetByName(target_type, &info)) {
+        return false;
+    }
+    if (target_type == "snapshot") {
+        return info.IsAtLeast(1, 15, 0);
+    }
+    if (target_type == "snapshot-merge") {
+        return info.IsAtLeast(1, 4, 0);
+    }
+    return false;
+}
+
+bool DmTargetSnapshot::ParseStatusText(const std::string& text, Status* status) {
+    auto sections = android::base::Split(text, " ");
+    if (sections.size() == 1) {
+        // This is probably an error code, "Invalid" is possible as is "Overflow"
+        // on 4.4+.
+        status->error = text;
+        return true;
+    }
+    if (sections.size() != 2) {
+        LOG(ERROR) << "snapshot status should have two components";
+        return false;
+    }
+    auto sector_info = android::base::Split(sections[0], "/");
+    if (sector_info.size() != 2) {
+        LOG(ERROR) << "snapshot sector info should have two components";
+        return false;
+    }
+    if (!android::base::ParseUint(sections[1], &status->metadata_sectors)) {
+        LOG(ERROR) << "could not parse metadata sectors";
+        return false;
+    }
+    if (!android::base::ParseUint(sector_info[0], &status->sectors_allocated)) {
+        LOG(ERROR) << "could not parse sectors allocated";
+        return false;
+    }
+    if (!android::base::ParseUint(sector_info[1], &status->total_sectors)) {
+        LOG(ERROR) << "could not parse total sectors";
+        return false;
+    }
+    return true;
+}
+
 }  // namespace dm
 }  // namespace android
diff --git a/fs_mgr/libdm/dm_test.cpp b/fs_mgr/libdm/dm_test.cpp
index 70823c6..72a0e11 100644
--- a/fs_mgr/libdm/dm_test.cpp
+++ b/fs_mgr/libdm/dm_test.cpp
@@ -24,6 +24,7 @@
 
 #include <chrono>
 #include <ctime>
+#include <iostream>
 #include <map>
 #include <thread>
 
@@ -35,21 +36,15 @@
 #include "test_util.h"
 
 using namespace std;
+using namespace std::chrono_literals;
 using namespace android::dm;
 using unique_fd = android::base::unique_fd;
 
 TEST(libdm, HasMinimumTargets) {
+    DmTargetTypeInfo info;
+
     DeviceMapper& dm = DeviceMapper::Instance();
-    vector<DmTargetTypeInfo> targets;
-    ASSERT_TRUE(dm.GetAvailableTargets(&targets));
-
-    map<string, DmTargetTypeInfo> by_name;
-    for (const auto& target : targets) {
-        by_name[target.name()] = target;
-    }
-
-    auto iter = by_name.find("linear");
-    EXPECT_NE(iter, by_name.end());
+    ASSERT_TRUE(dm.GetTargetByName("linear", &info));
 }
 
 // Helper to ensure that device mapper devices are released.
@@ -201,3 +196,245 @@
             "2 fec_blocks 126955 fec_start 126955 restart_on_corruption ignore_zero_blocks";
     EXPECT_EQ(target.GetParameterString(), expected);
 }
+
+TEST(libdm, DmSnapshotArgs) {
+    DmTargetSnapshot target1(0, 512, "base", "cow", SnapshotStorageMode::Persistent, 8);
+    if (DmTargetSnapshot::ReportsOverflow("snapshot")) {
+        EXPECT_EQ(target1.GetParameterString(), "base cow PO 8");
+    } else {
+        EXPECT_EQ(target1.GetParameterString(), "base cow P 8");
+    }
+    EXPECT_EQ(target1.name(), "snapshot");
+
+    DmTargetSnapshot target2(0, 512, "base", "cow", SnapshotStorageMode::Transient, 8);
+    EXPECT_EQ(target2.GetParameterString(), "base cow N 8");
+    EXPECT_EQ(target2.name(), "snapshot");
+
+    DmTargetSnapshot target3(0, 512, "base", "cow", SnapshotStorageMode::Merge, 8);
+    if (DmTargetSnapshot::ReportsOverflow("snapshot-merge")) {
+        EXPECT_EQ(target3.GetParameterString(), "base cow PO 8");
+    } else {
+        EXPECT_EQ(target3.GetParameterString(), "base cow P 8");
+    }
+    EXPECT_EQ(target3.name(), "snapshot-merge");
+}
+
+TEST(libdm, DmSnapshotOriginArgs) {
+    DmTargetSnapshotOrigin target(0, 512, "base");
+    EXPECT_EQ(target.GetParameterString(), "base");
+    EXPECT_EQ(target.name(), "snapshot-origin");
+}
+
+class SnapshotTestHarness final {
+  public:
+    bool Setup();
+    bool Merge();
+
+    std::string origin_dev() const { return origin_dev_->path(); }
+    std::string snapshot_dev() const { return snapshot_dev_->path(); }
+
+    int base_fd() const { return base_fd_; }
+
+    static const uint64_t kBaseDeviceSize = 1024 * 1024;
+    static const uint64_t kCowDeviceSize = 1024 * 64;
+    static const uint64_t kSectorSize = 512;
+
+  private:
+    void SetupImpl();
+    void MergeImpl();
+
+    unique_fd base_fd_;
+    unique_fd cow_fd_;
+    unique_ptr<LoopDevice> base_loop_;
+    unique_ptr<LoopDevice> cow_loop_;
+    unique_ptr<TempDevice> origin_dev_;
+    unique_ptr<TempDevice> snapshot_dev_;
+    bool setup_ok_ = false;
+    bool merge_ok_ = false;
+};
+
+bool SnapshotTestHarness::Setup() {
+    SetupImpl();
+    return setup_ok_;
+}
+
+void SnapshotTestHarness::SetupImpl() {
+    base_fd_ = CreateTempFile("base_device", kBaseDeviceSize);
+    ASSERT_GE(base_fd_, 0);
+    cow_fd_ = CreateTempFile("cow_device", kCowDeviceSize);
+    ASSERT_GE(cow_fd_, 0);
+
+    base_loop_ = std::make_unique<LoopDevice>(base_fd_);
+    ASSERT_TRUE(base_loop_->valid());
+    cow_loop_ = std::make_unique<LoopDevice>(cow_fd_);
+    ASSERT_TRUE(cow_loop_->valid());
+
+    DmTable origin_table;
+    ASSERT_TRUE(origin_table.AddTarget(make_unique<DmTargetSnapshotOrigin>(
+            0, kBaseDeviceSize / kSectorSize, base_loop_->device())));
+    ASSERT_TRUE(origin_table.valid());
+
+    origin_dev_ = std::make_unique<TempDevice>("libdm-test-dm-snapshot-origin", origin_table);
+    ASSERT_TRUE(origin_dev_->valid());
+    ASSERT_FALSE(origin_dev_->path().empty());
+    ASSERT_TRUE(origin_dev_->WaitForUdev());
+
+    // chunk size = 4K blocks.
+    DmTable snap_table;
+    ASSERT_TRUE(snap_table.AddTarget(make_unique<DmTargetSnapshot>(
+            0, kBaseDeviceSize / kSectorSize, base_loop_->device(), cow_loop_->device(),
+            SnapshotStorageMode::Persistent, 8)));
+    ASSERT_TRUE(snap_table.valid());
+
+    snapshot_dev_ = std::make_unique<TempDevice>("libdm-test-dm-snapshot", snap_table);
+    ASSERT_TRUE(snapshot_dev_->valid());
+    ASSERT_FALSE(snapshot_dev_->path().empty());
+    ASSERT_TRUE(snapshot_dev_->WaitForUdev());
+
+    setup_ok_ = true;
+}
+
+bool SnapshotTestHarness::Merge() {
+    MergeImpl();
+    return merge_ok_;
+}
+
+void SnapshotTestHarness::MergeImpl() {
+    DmTable merge_table;
+    ASSERT_TRUE(merge_table.AddTarget(
+            make_unique<DmTargetSnapshot>(0, kBaseDeviceSize / kSectorSize, base_loop_->device(),
+                                          cow_loop_->device(), SnapshotStorageMode::Merge, 8)));
+    ASSERT_TRUE(merge_table.valid());
+
+    DeviceMapper& dm = DeviceMapper::Instance();
+    ASSERT_TRUE(dm.LoadTableAndActivate("libdm-test-dm-snapshot", merge_table));
+
+    while (true) {
+        vector<DeviceMapper::TargetInfo> status;
+        ASSERT_TRUE(dm.GetTableStatus("libdm-test-dm-snapshot", &status));
+        ASSERT_EQ(status.size(), 1);
+        ASSERT_EQ(strncmp(status[0].spec.target_type, "snapshot-merge", strlen("snapshot-merge")),
+                  0);
+
+        DmTargetSnapshot::Status merge_status;
+        ASSERT_TRUE(DmTargetSnapshot::ParseStatusText(status[0].data, &merge_status));
+        ASSERT_TRUE(merge_status.error.empty());
+        if (merge_status.sectors_allocated == merge_status.metadata_sectors) {
+            break;
+        }
+
+        std::this_thread::sleep_for(250ms);
+    }
+
+    merge_ok_ = true;
+}
+
+bool CheckSnapshotAvailability() {
+    DmTargetTypeInfo info;
+
+    DeviceMapper& dm = DeviceMapper::Instance();
+    if (!dm.GetTargetByName("snapshot", &info)) {
+        cout << "snapshot module not enabled; skipping test" << std::endl;
+        return false;
+    }
+    if (!dm.GetTargetByName("snapshot-merge", &info)) {
+        cout << "snapshot-merge module not enabled; skipping test" << std::endl;
+        return false;
+    }
+    if (!dm.GetTargetByName("snapshot-origin", &info)) {
+        cout << "snapshot-origin module not enabled; skipping test" << std::endl;
+        return false;
+    }
+    return true;
+}
+
+TEST(libdm, DmSnapshot) {
+    if (!CheckSnapshotAvailability()) {
+        return;
+    }
+
+    SnapshotTestHarness harness;
+    ASSERT_TRUE(harness.Setup());
+
+    // Open the dm devices.
+    unique_fd origin_fd(open(harness.origin_dev().c_str(), O_RDONLY | O_CLOEXEC));
+    ASSERT_GE(origin_fd, 0);
+    unique_fd snapshot_fd(open(harness.snapshot_dev().c_str(), O_RDWR | O_CLOEXEC | O_SYNC));
+    ASSERT_GE(snapshot_fd, 0);
+
+    // Write to the first block of the snapshot device.
+    std::string data("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
+    ASSERT_TRUE(android::base::WriteFully(snapshot_fd, data.data(), data.size()));
+    ASSERT_EQ(lseek(snapshot_fd, 0, SEEK_SET), 0);
+
+    // We should get the same data back from the snapshot device.
+    std::string read(data.size(), '\0');
+    ASSERT_TRUE(android::base::ReadFully(snapshot_fd, read.data(), read.size()));
+    ASSERT_EQ(read, data);
+
+    // We should see the original data from the origin device.
+    std::string zeroes(data.size(), '\0');
+    ASSERT_TRUE(android::base::ReadFully(origin_fd, read.data(), read.size()));
+    ASSERT_EQ(lseek(snapshot_fd, 0, SEEK_SET), 0);
+    ASSERT_EQ(read, zeroes);
+
+    // We should also see the original data from the base device.
+    ASSERT_TRUE(android::base::ReadFully(harness.base_fd(), read.data(), read.size()));
+    ASSERT_EQ(lseek(harness.base_fd(), 0, SEEK_SET), 0);
+    ASSERT_EQ(read, zeroes);
+
+    // Now, perform the merge and wait.
+    ASSERT_TRUE(harness.Merge());
+
+    // Reading from the base device should give us the modified data.
+    ASSERT_TRUE(android::base::ReadFully(harness.base_fd(), read.data(), read.size()));
+    ASSERT_EQ(lseek(harness.base_fd(), 0, SEEK_SET), 0);
+    ASSERT_EQ(read, data);
+}
+
+TEST(libdm, DmSnapshotOverflow) {
+    if (!CheckSnapshotAvailability()) {
+        return;
+    }
+
+    SnapshotTestHarness harness;
+    ASSERT_TRUE(harness.Setup());
+
+    // Open the dm devices.
+    unique_fd snapshot_fd(open(harness.snapshot_dev().c_str(), O_RDWR | O_CLOEXEC));
+    ASSERT_GE(snapshot_fd, 0);
+
+    // Fill the copy-on-write device until it overflows.
+    uint64_t bytes_remaining = SnapshotTestHarness::kCowDeviceSize;
+    uint8_t byte = 1;
+    while (bytes_remaining) {
+        std::string data(4096, char(byte));
+        if (!android::base::WriteFully(snapshot_fd, data.data(), data.size())) {
+            ASSERT_EQ(errno, EIO);
+            break;
+        }
+        bytes_remaining -= data.size();
+    }
+
+    // If writes succeed (because they are buffered), then we should expect an
+    // fsync to fail with EIO.
+    if (!bytes_remaining) {
+        ASSERT_EQ(fsync(snapshot_fd), -1);
+        ASSERT_EQ(errno, EIO);
+    }
+
+    DeviceMapper& dm = DeviceMapper::Instance();
+
+    vector<DeviceMapper::TargetInfo> target_status;
+    ASSERT_TRUE(dm.GetTableStatus("libdm-test-dm-snapshot", &target_status));
+    ASSERT_EQ(target_status.size(), 1);
+    ASSERT_EQ(strncmp(target_status[0].spec.target_type, "snapshot", strlen("snapshot")), 0);
+
+    DmTargetSnapshot::Status status;
+    ASSERT_TRUE(DmTargetSnapshot::ParseStatusText(target_status[0].data, &status));
+    if (DmTargetSnapshot::ReportsOverflow("snapshot")) {
+        ASSERT_EQ(status.error, "Overflow");
+    } else {
+        ASSERT_EQ(status.error, "Invalid");
+    }
+}
diff --git a/fs_mgr/libdm/include/libdm/dm.h b/fs_mgr/libdm/include/libdm/dm.h
index 28e6e01..d7e8aa9 100644
--- a/fs_mgr/libdm/include/libdm/dm.h
+++ b/fs_mgr/libdm/include/libdm/dm.h
@@ -96,6 +96,10 @@
     // successfully read and stored in 'targets'. Returns 'false' otherwise.
     bool GetAvailableTargets(std::vector<DmTargetTypeInfo>* targets);
 
+    // Finds a target by name and returns its information if found. |info| may
+    // be null to check for the existence of a target.
+    bool GetTargetByName(const std::string& name, DmTargetTypeInfo* info);
+
     // Return 'true' if it can successfully read the list of device mapper block devices
     // currently created. 'devices' will be empty if the kernel interactions
     // were successful and there are no block devices at the moment. Returns
diff --git a/fs_mgr/libdm/include/libdm/dm_target.h b/fs_mgr/libdm/include/libdm/dm_target.h
index 175b0f0..fce1175 100644
--- a/fs_mgr/libdm/include/libdm/dm_target.h
+++ b/fs_mgr/libdm/include/libdm/dm_target.h
@@ -40,6 +40,18 @@
         return std::to_string(major_) + "." + std::to_string(minor_) + "." + std::to_string(patch_);
     }
 
+    uint32_t major_version() const { return major_; }
+    uint32_t minor_version() const { return minor_; }
+    uint32_t patch_level() const { return patch_; }
+
+    bool IsAtLeast(uint32_t major, uint32_t minor, uint32_t patch) const {
+        if (major_ > major) return true;
+        if (major_ < major) return false;
+        if (minor_ > minor) return true;
+        if (minor_ < minor) return false;
+        return patch_ >= patch;
+    }
+
   private:
     std::string name_;
     uint32_t major_;
@@ -170,6 +182,65 @@
     std::string target_string_;
 };
 
+enum class SnapshotStorageMode {
+    // The snapshot will be persisted to the COW device.
+    Persistent,
+    // The snapshot will be lost on reboot.
+    Transient,
+    // The snapshot will be merged from the COW device into the base device,
+    // in the background.
+    Merge
+};
+
+// Writes to a snapshot device will be written to the given COW device. Reads
+// will read from the COW device or base device. The chunk size is specified
+// in sectors.
+class DmTargetSnapshot final : public DmTarget {
+  public:
+    DmTargetSnapshot(uint64_t start, uint64_t length, const std::string& base_device,
+                     const std::string& cow_device, SnapshotStorageMode mode, uint64_t chunk_size)
+        : DmTarget(start, length),
+          base_device_(base_device),
+          cow_device_(cow_device),
+          mode_(mode),
+          chunk_size_(chunk_size) {}
+
+    std::string name() const override;
+    std::string GetParameterString() const override;
+    bool Valid() const override { return true; }
+
+    struct Status {
+        uint64_t sectors_allocated;
+        uint64_t total_sectors;
+        uint64_t metadata_sectors;
+        std::string error;
+    };
+
+    static bool ParseStatusText(const std::string& text, Status* status);
+    static bool ReportsOverflow(const std::string& target_type);
+
+  private:
+    std::string base_device_;
+    std::string cow_device_;
+    SnapshotStorageMode mode_;
+    uint64_t chunk_size_;
+};
+
+// snapshot-origin will read/write directly to the backing device, updating any
+// snapshot devices with a matching origin.
+class DmTargetSnapshotOrigin final : public DmTarget {
+  public:
+    DmTargetSnapshotOrigin(uint64_t start, uint64_t length, const std::string& device)
+        : DmTarget(start, length), device_(device) {}
+
+    std::string name() const override { return "snapshot-origin"; }
+    std::string GetParameterString() const override { return device_; }
+    bool Valid() const override { return true; }
+
+  private:
+    std::string device_;
+};
+
 }  // namespace dm
 }  // namespace android
 
diff --git a/fs_mgr/tests/fs_mgr_test.cpp b/fs_mgr/tests/fs_mgr_test.cpp
index 72afa69..6d87594 100644
--- a/fs_mgr/tests/fs_mgr_test.cpp
+++ b/fs_mgr/tests/fs_mgr_test.cpp
@@ -394,7 +394,7 @@
     std::string fstab_contents = R"fs(
 source none0       swap   defaults      encryptable,forceencrypt,fileencryption,forcefdeorfbe,keydirectory,length,swapprio,zramsize,max_comp_streams,reservedsize,eraseblk,logicalblk,sysfs_path,zram_loopback_path,zram_loopback_size,zram_backing_dev_path
 
-source none1       swap   defaults      encryptable=,forceencrypt=,fileencryption=,keydirectory=,length=,swapprio=,zramsize=,max_comp_streams=,verify=,avb=,reservedsize=,eraseblk=,logicalblk=,sysfs_path=,zram_loopback_path=,zram_loopback_size=,zram_backing_dev_path=
+source none1       swap   defaults      encryptable=,forceencrypt=,fileencryption=,keydirectory=,length=,swapprio=,zramsize=,max_comp_streams=,avb=,reservedsize=,eraseblk=,logicalblk=,sysfs_path=,zram_loopback_path=,zram_loopback_size=,zram_backing_dev_path=
 
 source none2       swap   defaults      forcefdeorfbe=
 
@@ -413,7 +413,6 @@
     }
     EXPECT_EQ("", entry->key_loc);
     EXPECT_EQ("", entry->key_dir);
-    EXPECT_EQ("", entry->verity_loc);
     EXPECT_EQ(0, entry->length);
     EXPECT_EQ("", entry->label);
     EXPECT_EQ(-1, entry->partnum);
@@ -437,13 +436,11 @@
         flags.crypt = true;
         flags.force_crypt = true;
         flags.file_encryption = true;
-        flags.verify = true;
         flags.avb = true;
         EXPECT_TRUE(CompareFlags(flags, entry->fs_mgr_flags));
     }
     EXPECT_EQ("", entry->key_loc);
     EXPECT_EQ("", entry->key_dir);
-    EXPECT_EQ("", entry->verity_loc);
     EXPECT_EQ(0, entry->length);
     EXPECT_EQ("", entry->label);
     EXPECT_EQ(-1, entry->partnum);
@@ -639,29 +636,6 @@
     EXPECT_EQ(0, entry->zram_size);
 }
 
-TEST(fs_mgr, ReadFstabFromFile_FsMgrOptions_Verify) {
-    TemporaryFile tf;
-    ASSERT_TRUE(tf.fd != -1);
-    std::string fstab_contents = R"fs(
-source none0       swap   defaults      verify=/dir/key
-)fs";
-
-    ASSERT_TRUE(android::base::WriteStringToFile(fstab_contents, tf.path));
-
-    Fstab fstab;
-    EXPECT_TRUE(ReadFstabFromFile(tf.path, &fstab));
-    ASSERT_EQ(1U, fstab.size());
-
-    auto entry = fstab.begin();
-    EXPECT_EQ("none0", entry->mount_point);
-
-    FstabEntry::FsMgrFlags flags = {};
-    flags.verify = true;
-    EXPECT_TRUE(CompareFlags(flags, entry->fs_mgr_flags));
-
-    EXPECT_EQ("/dir/key", entry->verity_loc);
-}
-
 TEST(fs_mgr, ReadFstabFromFile_FsMgrOptions_ForceEncrypt) {
     TemporaryFile tf;
     ASSERT_TRUE(tf.fd != -1);
diff --git a/fs_mgr/tools/dmctl.cpp b/fs_mgr/tools/dmctl.cpp
index 9309aad..7e6ad5b 100644
--- a/fs_mgr/tools/dmctl.cpp
+++ b/fs_mgr/tools/dmctl.cpp
@@ -38,15 +38,7 @@
 #include <vector>
 
 using namespace std::literals::string_literals;
-
-using DeviceMapper = ::android::dm::DeviceMapper;
-using DmTable = ::android::dm::DmTable;
-using DmTarget = ::android::dm::DmTarget;
-using DmTargetLinear = ::android::dm::DmTargetLinear;
-using DmTargetZero = ::android::dm::DmTargetZero;
-using DmTargetAndroidVerity = ::android::dm::DmTargetAndroidVerity;
-using DmTargetBow = ::android::dm::DmTargetBow;
-using DmTargetTypeInfo = ::android::dm::DmTargetTypeInfo;
+using namespace android::dm;
 using DmBlockDevice = ::android::dm::DeviceMapper::DmBlockDevice;
 
 static int Usage(void) {
@@ -57,6 +49,7 @@
     std::cerr << "  delete <dm-name>" << std::endl;
     std::cerr << "  list <devices | targets> [-v]" << std::endl;
     std::cerr << "  getpath <dm-name>" << std::endl;
+    std::cerr << "  status <dm-name>" << std::endl;
     std::cerr << "  table <dm-name>" << std::endl;
     std::cerr << "  help" << std::endl;
     std::cerr << std::endl;
@@ -122,6 +115,62 @@
             }
             std::string block_device = NextArg();
             return std::make_unique<DmTargetBow>(start_sector, num_sectors, block_device);
+        } else if (target_type == "snapshot-origin") {
+            if (!HasArgs(1)) {
+                std::cerr << "Expected \"snapshot-origin\" <block_device>" << std::endl;
+                return nullptr;
+            }
+            std::string block_device = NextArg();
+            return std::make_unique<DmTargetSnapshotOrigin>(start_sector, num_sectors,
+                                                            block_device);
+        } else if (target_type == "snapshot") {
+            if (!HasArgs(4)) {
+                std::cerr
+                        << "Expected \"snapshot\" <block_device> <block_device> <mode> <chunk_size>"
+                        << std::endl;
+                return nullptr;
+            }
+            std::string base_device = NextArg();
+            std::string cow_device = NextArg();
+            std::string mode_str = NextArg();
+            std::string chunk_size_str = NextArg();
+
+            SnapshotStorageMode mode;
+            if (mode_str == "P") {
+                mode = SnapshotStorageMode::Persistent;
+            } else if (mode_str == "N") {
+                mode = SnapshotStorageMode::Transient;
+            } else {
+                std::cerr << "Unrecognized mode: " << mode_str << "\n";
+                return nullptr;
+            }
+
+            uint32_t chunk_size;
+            if (!android::base::ParseUint(chunk_size_str, &chunk_size)) {
+                std::cerr << "Chunk size must be an unsigned integer.\n";
+                return nullptr;
+            }
+            return std::make_unique<DmTargetSnapshot>(start_sector, num_sectors, base_device,
+                                                      cow_device, mode, chunk_size);
+        } else if (target_type == "snapshot-merge") {
+            if (!HasArgs(3)) {
+                std::cerr
+                        << "Expected \"snapshot-merge\" <block_device> <block_device> <chunk_size>"
+                        << std::endl;
+                return nullptr;
+            }
+            std::string base_device = NextArg();
+            std::string cow_device = NextArg();
+            std::string chunk_size_str = NextArg();
+            SnapshotStorageMode mode = SnapshotStorageMode::Merge;
+
+            uint32_t chunk_size;
+            if (!android::base::ParseUint(chunk_size_str, &chunk_size)) {
+                std::cerr << "Chunk size must be an unsigned integer.\n";
+                return nullptr;
+            }
+            return std::make_unique<DmTargetSnapshot>(start_sector, num_sectors, base_device,
+                                                      cow_device, mode, chunk_size);
         } else {
             std::cerr << "Unrecognized target type: " << target_type << std::endl;
             return nullptr;
@@ -308,7 +357,7 @@
     return 0;
 }
 
-static int TableCmdHandler(int argc, char** argv) {
+static int DumpTable(const std::string& mode, int argc, char** argv) {
     if (argc != 1) {
         std::cerr << "Invalid arguments, see \'dmctl help\'" << std::endl;
         return -EINVAL;
@@ -316,9 +365,18 @@
 
     DeviceMapper& dm = DeviceMapper::Instance();
     std::vector<DeviceMapper::TargetInfo> table;
-    if (!dm.GetTableInfo(argv[0], &table)) {
-        std::cerr << "Could not query table status of device \"" << argv[0] << "\"." << std::endl;
-        return -EINVAL;
+    if (mode == "status") {
+        if (!dm.GetTableStatus(argv[0], &table)) {
+            std::cerr << "Could not query table status of device \"" << argv[0] << "\"."
+                      << std::endl;
+            return -EINVAL;
+        }
+    } else if (mode == "table") {
+        if (!dm.GetTableInfo(argv[0], &table)) {
+            std::cerr << "Could not query table status of device \"" << argv[0] << "\"."
+                      << std::endl;
+            return -EINVAL;
+        }
     }
     std::cout << "Targets in the device-mapper table for " << argv[0] << ":" << std::endl;
     for (const auto& target : table) {
@@ -333,6 +391,14 @@
     return 0;
 }
 
+static int TableCmdHandler(int argc, char** argv) {
+    return DumpTable("table", argc, argv);
+}
+
+static int StatusCmdHandler(int argc, char** argv) {
+    return DumpTable("status", argc, argv);
+}
+
 static std::map<std::string, std::function<int(int, char**)>> cmdmap = {
         // clang-format off
         {"create", DmCreateCmdHandler},
@@ -341,6 +407,7 @@
         {"help", HelpCmdHandler},
         {"getpath", GetPathCmdHandler},
         {"table", TableCmdHandler},
+        {"status", StatusCmdHandler},
         // clang-format on
 };
 
diff --git a/init/README.md b/init/README.md
index 28a106a..d7f809f 100644
--- a/init/README.md
+++ b/init/README.md
@@ -586,9 +586,6 @@
 `umount <path>`
 > Unmount the filesystem mounted at that path.
 
-`verity_load_state`
-> Internal implementation detail used to load dm-verity state.
-
 `verity_update_state <mount-point>`
 > Internal implementation detail used to update dm-verity state and
   set the partition._mount-point_.verified properties used by adb remount
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 06da4be..62e0f8f 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -707,17 +707,6 @@
     return Success();
 }
 
-static Result<Success> do_verity_load_state(const BuiltinArguments& args) {
-    int mode = -1;
-    bool loaded = fs_mgr_load_verity_state(&mode);
-    if (loaded && mode != VERITY_MODE_DEFAULT) {
-        ActionManager::GetInstance().QueueEventTrigger("verity-logging");
-    }
-    if (!loaded) return Error() << "Could not load verity state";
-
-    return Success();
-}
-
 static Result<Success> do_verity_update_state(const BuiltinArguments& args) {
     int mode;
     if (!fs_mgr_load_verity_state(&mode)) {
@@ -1150,7 +1139,6 @@
         {"symlink",                 {2,     2,    {true,   do_symlink}}},
         {"sysclktz",                {1,     1,    {false,  do_sysclktz}}},
         {"trigger",                 {1,     1,    {false,  do_trigger}}},
-        {"verity_load_state",       {0,     0,    {false,  do_verity_load_state}}},
         {"verity_update_state",     {0,     0,    {false,  do_verity_update_state}}},
         {"wait",                    {1,     2,    {true,   do_wait}}},
         {"wait_for_prop",           {2,     2,    {false,  do_wait_for_prop}}},
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index 3e76556..85fa874 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -644,7 +644,6 @@
 }
 
 bool FirstStageMountVBootV1::GetDmVerityDevices() {
-    std::string verity_loc_device;
     need_dm_verity_ = false;
 
     for (const auto& fstab_entry : fstab_) {
@@ -657,21 +656,9 @@
         if (fstab_entry.fs_mgr_flags.verify) {
             need_dm_verity_ = true;
         }
-        // Checks if verity metadata is on a separate partition. Note that it is
-        // not partition specific, so there must be only one additional partition
-        // that carries verity state.
-        if (!fstab_entry.verity_loc.empty()) {
-            if (verity_loc_device.empty()) {
-                verity_loc_device = fstab_entry.verity_loc;
-            } else if (verity_loc_device != fstab_entry.verity_loc) {
-                LOG(ERROR) << "More than one verity_loc found: " << verity_loc_device << ", "
-                           << fstab_entry.verity_loc;
-                return false;
-            }
-        }
     }
 
-    // Includes the partition names of fstab records and verity_loc_device (if any).
+    // Includes the partition names of fstab records.
     // Notes that fstab_rec->blk_device has A/B suffix updated by fs_mgr when A/B is used.
     for (const auto& fstab_entry : fstab_) {
         if (!fstab_entry.fs_mgr_flags.logical) {
@@ -679,10 +666,6 @@
         }
     }
 
-    if (!verity_loc_device.empty()) {
-        required_devices_partition_names_.emplace(basename(verity_loc_device.c_str()));
-    }
-
     return true;
 }
 
diff --git a/init/selinux.cpp b/init/selinux.cpp
index 132fc13..c49dc9f 100644
--- a/init/selinux.cpp
+++ b/init/selinux.cpp
@@ -331,6 +331,12 @@
     }
     std::string plat_mapping_file("/system/etc/selinux/mapping/" + vend_plat_vers + ".cil");
 
+    std::string plat_compat_cil_file("/system/etc/selinux/mapping/" + vend_plat_vers +
+                                     ".compat.cil");
+    if (access(plat_compat_cil_file.c_str(), F_OK) == -1) {
+        plat_compat_cil_file.clear();
+    }
+
     std::string product_policy_cil_file("/product/etc/selinux/product_sepolicy.cil");
     if (access(product_policy_cil_file.c_str(), F_OK) == -1) {
         product_policy_cil_file.clear();
@@ -376,6 +382,9 @@
     };
     // clang-format on
 
+    if (!plat_compat_cil_file.empty()) {
+        compile_args.push_back(plat_compat_cil_file.c_str());
+    }
     if (!product_policy_cil_file.empty()) {
         compile_args.push_back(product_policy_cil_file.c_str());
     }
diff --git a/libziparchive/include/ziparchive/zip_archive.h b/libziparchive/include/ziparchive/zip_archive.h
index ab38dfd..32c6ea8 100644
--- a/libziparchive/include/ziparchive/zip_archive.h
+++ b/libziparchive/include/ziparchive/zip_archive.h
@@ -25,6 +25,8 @@
 #include <sys/cdefs.h>
 #include <sys/types.h>
 
+#include <string_view>
+
 #include "android-base/off64_t.h"
 
 /* Zip compression methods we support */
@@ -39,10 +41,7 @@
 
   ZipString() {}
 
-  /*
-   * entry_name has to be an c-style string with only ASCII characters.
-   */
-  explicit ZipString(const char* entry_name);
+  explicit ZipString(std::string_view entry_name);
 
   bool operator==(const ZipString& rhs) const {
     return name && (name_length == rhs.name_length) && (memcmp(name, rhs.name, name_length) == 0);
@@ -149,8 +148,7 @@
 void CloseArchive(ZipArchiveHandle archive);
 
 /*
- * Find an entry in the Zip archive, by name. |entryName| must be a null
- * terminated string, and |data| must point to a writeable memory location.
+ * Find an entry in the Zip archive, by name. |data| must be non-null.
  *
  * Returns 0 if an entry is found, and populates |data| with information
  * about this entry. Returns negative values otherwise.
@@ -164,6 +162,8 @@
  * On non-Windows platforms this method does not modify internal state and
  * can be called concurrently.
  */
+int32_t FindEntry(const ZipArchiveHandle archive, const std::string_view entryName, ZipEntry* data);
+// TODO: remove this internally, where there is a new user.
 int32_t FindEntry(const ZipArchiveHandle archive, const ZipString& entryName, ZipEntry* data);
 
 /*
@@ -179,6 +179,7 @@
  *
  * Returns 0 on success and negative values on failure.
  */
+// TODO: switch these ZipStrings to std::string_view.
 int32_t StartIteration(ZipArchiveHandle archive, void** cookie_ptr,
                        const ZipString* optional_prefix, const ZipString* optional_suffix);
 
diff --git a/libziparchive/zip_archive.cc b/libziparchive/zip_archive.cc
index 596786a..bc7103b 100644
--- a/libziparchive/zip_archive.cc
+++ b/libziparchive/zip_archive.cc
@@ -690,8 +690,7 @@
 
 struct IterationHandle {
   uint32_t position;
-  // We're not using vector here because this code is used in the Windows SDK
-  // where the STL is not available.
+  // TODO: switch these to std::string now that Windows uses libc++ too.
   ZipString prefix;
   ZipString suffix;
   ZipArchive* archive;
@@ -742,6 +741,7 @@
   delete reinterpret_cast<IterationHandle*>(cookie);
 }
 
+// TODO: remove this internally.
 int32_t FindEntry(const ZipArchiveHandle archive, const ZipString& entryName, ZipEntry* data) {
   if (entryName.name_length == 0) {
     ALOGW("Zip: Invalid filename %.*s", entryName.name_length, entryName.name);
@@ -758,6 +758,23 @@
   return FindEntry(archive, static_cast<uint32_t>(ent), data);
 }
 
+int32_t FindEntry(const ZipArchiveHandle archive, const std::string_view entryName,
+                  ZipEntry* data) {
+  if (entryName.empty() || entryName.size() > static_cast<size_t>(UINT16_MAX)) {
+    ALOGW("Zip: Invalid filename of length %zu", entryName.size());
+    return kInvalidEntryName;
+  }
+
+  const int64_t ent = EntryToIndex(archive->hash_table, archive->hash_table_size,
+                                   ZipString(entryName), archive->central_directory.GetBasePtr());
+  if (ent < 0) {
+    ALOGV("Zip: Could not find entry %.*s", static_cast<int>(entryName.size()), entryName.data());
+    return static_cast<int32_t>(ent);  // kEntryNotFound is safe to truncate.
+  }
+  // We know there are at most hast_table_size entries, safe to truncate.
+  return FindEntry(archive, static_cast<uint32_t>(ent), data);
+}
+
 int32_t Next(void* cookie, ZipEntry* data, ZipString* name) {
   IterationHandle* handle = reinterpret_cast<IterationHandle*>(cookie);
   if (handle == NULL) {
@@ -1152,8 +1169,9 @@
   return archive->mapped_zip.GetFileDescriptor();
 }
 
-ZipString::ZipString(const char* entry_name) : name(reinterpret_cast<const uint8_t*>(entry_name)) {
-  size_t len = strlen(entry_name);
+ZipString::ZipString(std::string_view entry_name)
+    : name(reinterpret_cast<const uint8_t*>(entry_name.data())) {
+  size_t len = entry_name.size();
   CHECK_LE(len, static_cast<size_t>(UINT16_MAX));
   name_length = static_cast<uint16_t>(len);
 }
diff --git a/libziparchive/zip_archive_benchmark.cpp b/libziparchive/zip_archive_benchmark.cpp
index 46aa5a6..52166a4 100644
--- a/libziparchive/zip_archive_benchmark.cpp
+++ b/libziparchive/zip_archive_benchmark.cpp
@@ -55,7 +55,7 @@
 
   // In order to walk through all file names in the archive, look for a name
   // that does not exist in the archive.
-  ZipString name("thisFileNameDoesNotExist");
+  std::string_view name("thisFileNameDoesNotExist");
 
   // Start the benchmark.
   while (state.KeepRunning()) {
diff --git a/libziparchive/zip_archive_test.cc b/libziparchive/zip_archive_test.cc
index e471d5e..cfbce1c 100644
--- a/libziparchive/zip_archive_test.cc
+++ b/libziparchive/zip_archive_test.cc
@@ -64,12 +64,6 @@
   return OpenArchive(abs_path.c_str(), handle);
 }
 
-static void SetZipString(ZipString* zip_str, const std::string& str) {
-  zip_str->name = reinterpret_cast<const uint8_t*>(str.c_str());
-  CHECK_LE(str.size(), std::numeric_limits<uint16_t>::max());
-  zip_str->name_length = static_cast<uint16_t>(str.size());
-}
-
 TEST(ziparchive, Open) {
   ZipArchiveHandle handle;
   ASSERT_EQ(0, OpenArchiveWrapper(kValidZip, &handle));
@@ -192,9 +186,7 @@
   ASSERT_EQ(0, OpenArchiveWrapper(kValidZip, &handle));
 
   ZipEntry data;
-  ZipString name;
-  SetZipString(&name, kATxtName);
-  ASSERT_EQ(0, FindEntry(handle, name, &data));
+  ASSERT_EQ(0, FindEntry(handle, kATxtName, &data));
 
   // Known facts about a.txt, from zipinfo -v.
   ASSERT_EQ(63, data.offset);
@@ -205,9 +197,28 @@
   ASSERT_EQ(static_cast<uint32_t>(0x438a8005), data.mod_time);
 
   // An entry that doesn't exist. Should be a negative return code.
-  ZipString absent_name;
-  SetZipString(&absent_name, kNonexistentTxtName);
-  ASSERT_LT(FindEntry(handle, absent_name, &data), 0);
+  ASSERT_LT(FindEntry(handle, kNonexistentTxtName, &data), 0);
+
+  CloseArchive(handle);
+}
+
+TEST(ziparchive, FindEntry_empty) {
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveWrapper(kValidZip, &handle));
+
+  ZipEntry data;
+  ASSERT_EQ(kInvalidEntryName, FindEntry(handle, "", &data));
+
+  CloseArchive(handle);
+}
+
+TEST(ziparchive, FindEntry_too_long) {
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveWrapper(kValidZip, &handle));
+
+  std::string very_long_name(65536, 'x');
+  ZipEntry data;
+  ASSERT_EQ(kInvalidEntryName, FindEntry(handle, very_long_name, &data));
 
   CloseArchive(handle);
 }
@@ -234,9 +245,7 @@
 
   // An entry that's deflated.
   ZipEntry data;
-  ZipString a_name;
-  SetZipString(&a_name, kATxtName);
-  ASSERT_EQ(0, FindEntry(handle, a_name, &data));
+  ASSERT_EQ(0, FindEntry(handle, kATxtName, &data));
   const uint32_t a_size = data.uncompressed_length;
   ASSERT_EQ(a_size, kATxtContents.size());
   uint8_t* buffer = new uint8_t[a_size];
@@ -245,9 +254,7 @@
   delete[] buffer;
 
   // An entry that's stored.
-  ZipString b_name;
-  SetZipString(&b_name, kBTxtName);
-  ASSERT_EQ(0, FindEntry(handle, b_name, &data));
+  ASSERT_EQ(0, FindEntry(handle, kBTxtName, &data));
   const uint32_t b_size = data.uncompressed_length;
   ASSERT_EQ(b_size, kBTxtContents.size());
   buffer = new uint8_t[b_size];
@@ -302,9 +309,7 @@
   ASSERT_EQ(0, OpenArchiveFd(tmp_file.fd, "EmptyEntriesTest", &handle, false));
 
   ZipEntry entry;
-  ZipString empty_name;
-  SetZipString(&empty_name, kEmptyTxtName);
-  ASSERT_EQ(0, FindEntry(handle, empty_name, &entry));
+  ASSERT_EQ(0, FindEntry(handle, kEmptyTxtName, &entry));
   ASSERT_EQ(static_cast<uint32_t>(0), entry.uncompressed_length);
   uint8_t buffer[1];
   ASSERT_EQ(0, ExtractToMemory(handle, &entry, buffer, 1));
@@ -327,9 +332,7 @@
   ASSERT_EQ(0, OpenArchiveFd(tmp_file.fd, "EntryLargerThan32KTest", &handle, false));
 
   ZipEntry entry;
-  ZipString ab_name;
-  SetZipString(&ab_name, kAbTxtName);
-  ASSERT_EQ(0, FindEntry(handle, ab_name, &entry));
+  ASSERT_EQ(0, FindEntry(handle, kAbTxtName, &entry));
   ASSERT_EQ(kAbUncompressedSize, entry.uncompressed_length);
 
   // Extract the entry to memory.
@@ -386,9 +389,7 @@
   ASSERT_EQ(0, OpenArchiveWrapper(kValidZip, &handle));
 
   ZipEntry entry;
-  ZipString name;
-  SetZipString(&name, kATxtName);
-  ASSERT_EQ(0, FindEntry(handle, name, &entry));
+  ASSERT_EQ(0, FindEntry(handle, kATxtName, &entry));
   ASSERT_EQ(0, ExtractEntryToFile(handle, &entry, tmp_file.fd));
 
   // Assert that the first 8 bytes of the file haven't been clobbered.
@@ -424,10 +425,8 @@
             OpenArchiveFromMemory(file_map->data(), file_map->size(), zip_path.c_str(), &handle));
 
   // Assert one entry can be found and extracted correctly.
-  std::string BINARY_PATH("META-INF/com/google/android/update-binary");
-  ZipString binary_path(BINARY_PATH.c_str());
   ZipEntry binary_entry;
-  ASSERT_EQ(0, FindEntry(handle, binary_path, &binary_entry));
+  ASSERT_EQ(0, FindEntry(handle, "META-INF/com/google/android/update-binary", &binary_entry));
   TemporaryFile tmp_binary;
   ASSERT_NE(-1, tmp_binary.fd);
   ASSERT_EQ(0, ExtractEntryToFile(handle, &binary_entry, tmp_binary.fd));
@@ -436,9 +435,7 @@
 
 static void ZipArchiveStreamTest(ZipArchiveHandle& handle, const std::string& entry_name, bool raw,
                                  bool verified, ZipEntry* entry, std::vector<uint8_t>* read_data) {
-  ZipString name;
-  SetZipString(&name, entry_name);
-  ASSERT_EQ(0, FindEntry(handle, name, entry));
+  ASSERT_EQ(0, FindEntry(handle, entry_name, entry));
   std::unique_ptr<ZipArchiveStreamEntry> stream;
   if (raw) {
     stream.reset(ZipArchiveStreamEntry::CreateRaw(handle, *entry));
@@ -589,11 +586,7 @@
   // an entry whose name is "name" and whose size is 12 (contents =
   // "abdcdefghijk").
   ZipEntry entry;
-  ZipString name;
-  std::string name_str = "name";
-  SetZipString(&name, name_str);
-
-  ASSERT_EQ(0, FindEntry(handle, name, &entry));
+  ASSERT_EQ(0, FindEntry(handle, "name", &entry));
   ASSERT_EQ(static_cast<uint32_t>(12), entry.uncompressed_length);
 
   entry_out->resize(12);
diff --git a/libziparchive/zip_writer_test.cc b/libziparchive/zip_writer_test.cc
index 63adbbc..c3da23c 100644
--- a/libziparchive/zip_writer_test.cc
+++ b/libziparchive/zip_writer_test.cc
@@ -62,7 +62,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("file.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "file.txt", &data));
   EXPECT_EQ(kCompressStored, data.method);
   EXPECT_EQ(0u, data.has_data_descriptor);
   EXPECT_EQ(strlen(expected), data.compressed_length);
@@ -95,19 +95,19 @@
 
   ZipEntry data;
 
-  ASSERT_EQ(0, FindEntry(handle, ZipString("file.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "file.txt", &data));
   EXPECT_EQ(kCompressStored, data.method);
   EXPECT_EQ(2u, data.compressed_length);
   ASSERT_EQ(2u, data.uncompressed_length);
   ASSERT_TRUE(AssertFileEntryContentsEq("he", handle, &data));
 
-  ASSERT_EQ(0, FindEntry(handle, ZipString("file/file.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "file/file.txt", &data));
   EXPECT_EQ(kCompressStored, data.method);
   EXPECT_EQ(3u, data.compressed_length);
   ASSERT_EQ(3u, data.uncompressed_length);
   ASSERT_TRUE(AssertFileEntryContentsEq("llo", handle, &data));
 
-  ASSERT_EQ(0, FindEntry(handle, ZipString("file/file2.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "file/file2.txt", &data));
   EXPECT_EQ(kCompressStored, data.method);
   EXPECT_EQ(0u, data.compressed_length);
   EXPECT_EQ(0u, data.uncompressed_length);
@@ -129,7 +129,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "align.txt", &data));
   EXPECT_EQ(0, data.offset & 0x03);
 
   CloseArchive(handle);
@@ -163,7 +163,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "align.txt", &data));
   EXPECT_EQ(0, data.offset & 0x03);
 
   struct tm mod = data.GetModificationTime();
@@ -191,7 +191,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "align.txt", &data));
   EXPECT_EQ(0, data.offset & 0xfff);
 
   CloseArchive(handle);
@@ -213,7 +213,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "align.txt", &data));
   EXPECT_EQ(0, data.offset & 0xfff);
 
   struct tm mod = data.GetModificationTime();
@@ -241,7 +241,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("file.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "file.txt", &data));
   EXPECT_EQ(kCompressDeflated, data.method);
   ASSERT_EQ(4u, data.uncompressed_length);
   ASSERT_TRUE(AssertFileEntryContentsEq("helo", handle, &data));
@@ -273,7 +273,7 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("file.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "file.txt", &data));
   EXPECT_EQ(kCompressDeflated, data.method);
   EXPECT_EQ(kBufSize, data.uncompressed_length);
 
@@ -340,12 +340,12 @@
   ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
 
   ZipEntry data;
-  ASSERT_EQ(0, FindEntry(handle, ZipString("keep.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "keep.txt", &data));
   ASSERT_TRUE(AssertFileEntryContentsEq(kKeepThis, handle, &data));
 
-  ASSERT_NE(0, FindEntry(handle, ZipString("drop.txt"), &data));
+  ASSERT_NE(0, FindEntry(handle, "drop.txt", &data));
 
-  ASSERT_EQ(0, FindEntry(handle, ZipString("replace.txt"), &data));
+  ASSERT_EQ(0, FindEntry(handle, "replace.txt", &data));
   ASSERT_TRUE(AssertFileEntryContentsEq(kReplaceWithThis, handle, &data));
 
   CloseArchive(handle);