fs_mgr: overlayfs create scratch using a Dynamic Logical Partition
The default is a valid /mnt/scratch/overlay/ or /cache/overlay/
directory, with .../<mount_point>/upper and .../<mount_point>/work,
associated with each system partition <mount_point>. Add support
for Dynamically Resized Partitions to create /mnt/scratch.
Test: manual
Bug: 109821005
Change-Id: I5e3f66778ea9e937c839e25541fedb6fbf34ab50
diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index a97369a..35f8be8 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -41,14 +41,18 @@
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <ext4_utils/ext4_utils.h>
+#include <fs_mgr_dm_linear.h>
#include <fs_mgr_overlayfs.h>
#include <fstab/fstab.h>
#include <libdm/dm.h>
+#include <liblp/builder.h>
+#include <liblp/liblp.h>
#include "fs_mgr_priv.h"
using namespace std::literals;
using namespace android::dm;
+using namespace android::fs_mgr;
#if ALLOW_ADBD_DISABLE_VERITY == 0 // If we are a user build, provide stubs
@@ -74,8 +78,10 @@
namespace {
-// acceptable overlayfs backing storage
-const auto kOverlayMountPoint = "/cache"s;
+// list of acceptable overlayfs backing storage
+const auto kScratchMountPoint = "/mnt/scratch"s;
+const auto kCacheMountPoint = "/cache"s;
+const std::vector<const std::string> kOverlayMountPoints = {kScratchMountPoint, kCacheMountPoint};
// Return true if everything is mounted, but before adb is started. Right
// after 'trigger load_persist_props_action' is done.
@@ -136,14 +142,17 @@
std::string fs_mgr_get_overlayfs_candidate(const std::string& mount_point) {
if (!fs_mgr_is_dir(mount_point)) return "";
- auto dir =
- kOverlayMountPoint + kOverlayTopDir + "/" + android::base::Basename(mount_point) + "/";
- auto upper = dir + kUpperName;
- if (!fs_mgr_is_dir(upper)) return "";
- auto work = dir + kWorkName;
- if (!fs_mgr_is_dir(work)) return "";
- if (!fs_mgr_dir_is_writable(work)) return "";
- return dir;
+ const auto base = android::base::Basename(mount_point) + "/";
+ for (const auto& overlay_mount_point : kOverlayMountPoints) {
+ auto dir = overlay_mount_point + kOverlayTopDir + "/" + base;
+ auto upper = dir + kUpperName;
+ if (!fs_mgr_is_dir(upper)) continue;
+ auto work = dir + kWorkName;
+ if (!fs_mgr_is_dir(work)) continue;
+ if (!fs_mgr_dir_is_writable(work)) continue;
+ return dir;
+ }
+ return "";
}
const auto kLowerdirOption = "lowerdir="s;
@@ -187,6 +196,14 @@
return ret;
}
+bool fs_mgr_rw_access(const std::string& path) {
+ if (path.empty()) return false;
+ auto save_errno = errno;
+ auto ret = access(path.c_str(), R_OK | W_OK) == 0;
+ errno = save_errno;
+ return ret;
+}
+
// return true if system supports overlayfs
bool fs_mgr_wants_overlayfs() {
// Properties will return empty on init first_stage_mount, so speculative
@@ -200,7 +217,7 @@
return fs_mgr_access("/sys/module/overlay/parameters/override_creds");
}
-bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point) {
+bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point, bool overlay_only = true) {
std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab("/proc/mounts"),
fs_mgr_free_fstab);
if (!fstab) return false;
@@ -209,10 +226,11 @@
const auto fsrec = &fstab->recs[i];
const auto fs_type = fsrec->fs_type;
if (!fs_type) continue;
- if (("overlay"s != fs_type) && ("overlayfs"s != fs_type)) continue;
+ if (overlay_only && ("overlay"s != fs_type) && ("overlayfs"s != fs_type)) continue;
auto fsrec_mount_point = fsrec->mount_point;
if (!fsrec_mount_point) continue;
if (mount_point != fsrec_mount_point) continue;
+ if (!overlay_only) return true;
const auto fs_options = fsrec->fs_options;
if (!fs_options) continue;
const auto options = android::base::Split(fs_options, ",");
@@ -373,6 +391,67 @@
return ret;
}
+uint32_t fs_mgr_overlayfs_slot_number() {
+ return SlotNumberForSlotSuffix(fs_mgr_get_slot_suffix());
+}
+
+std::string fs_mgr_overlayfs_super_device(uint32_t slot_number) {
+ return "/dev/block/by-name/" + fs_mgr_get_super_partition_name(slot_number);
+}
+
+bool fs_mgr_overlayfs_has_logical(const fstab* fstab) {
+ if (!fstab) return false;
+ for (auto i = 0; i < fstab->num_entries; i++) {
+ const auto fsrec = &fstab->recs[i];
+ if (fs_mgr_is_logical(fsrec)) return true;
+ }
+ return false;
+}
+
+// reduce 'DM_DEV_STATUS failed for scratch: No such device or address' noise
+std::string scratch_device_cache;
+
+bool fs_mgr_overlayfs_teardown_scratch(const std::string& overlay, bool* change) {
+ // umount and delete kScratchMountPoint storage if we have logical partitions
+ if (overlay != kScratchMountPoint) return true;
+ scratch_device_cache.erase();
+ auto slot_number = fs_mgr_overlayfs_slot_number();
+ auto super_device = fs_mgr_overlayfs_super_device(slot_number);
+ if (!fs_mgr_rw_access(super_device)) return true;
+
+ auto save_errno = errno;
+ if (fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) {
+ // Lazy umount will allow us to move on and possibly later
+ // establish a new fresh mount without requiring a reboot should
+ // the developer wish to restart. Old references should melt
+ // away or have no data. Main goal is to shut the door on the
+ // current overrides with an expectation of a subsequent reboot,
+ // thus any errors here are ignored.
+ umount2(kScratchMountPoint.c_str(), MNT_DETACH);
+ }
+ auto builder = MetadataBuilder::New(super_device, slot_number);
+ if (!builder) {
+ errno = save_errno;
+ return true;
+ }
+ const auto partition_name = android::base::Basename(kScratchMountPoint);
+ if (builder->FindPartition(partition_name) == nullptr) {
+ errno = save_errno;
+ return true;
+ }
+ builder->RemovePartition(partition_name);
+ auto metadata = builder->Export();
+ if (metadata && UpdatePartitionTable(super_device, *metadata.get(), slot_number)) {
+ if (change) *change = true;
+ if (!DestroyLogicalPartition(partition_name, 0s)) return false;
+ } else {
+ PERROR << "delete partition " << overlay;
+ return false;
+ }
+ errno = save_errno;
+ return true;
+}
+
bool fs_mgr_overlayfs_teardown_one(const std::string& overlay, const std::string& mount_point,
bool* change) {
const auto top = overlay + kOverlayTopDir;
@@ -406,13 +485,16 @@
save_errno = errno;
if (!rmdir(top.c_str())) {
if (change) *change = true;
+ cleanup_all = true;
} else if ((errno != ENOENT) && (errno != ENOTEMPTY)) {
ret = false;
PERROR << "rmdir " << top;
} else {
errno = save_errno;
+ cleanup_all = true;
}
}
+ if (cleanup_all) ret &= fs_mgr_overlayfs_teardown_scratch(overlay, change);
return ret;
}
@@ -504,6 +586,138 @@
return mounts;
}
+// Mount kScratchMountPoint
+bool fs_mgr_overlayfs_mount_scratch(const std::string& device_path, const std::string mnt_type) {
+ if (setfscreatecon(kOverlayfsFileContext)) {
+ PERROR << "setfscreatecon " << kOverlayfsFileContext;
+ }
+ if (mkdir(kScratchMountPoint.c_str(), 0755) && (errno != EEXIST)) {
+ PERROR << "create " << kScratchMountPoint;
+ }
+
+ std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> local_fstab(
+ static_cast<fstab*>(calloc(1, sizeof(fstab))), fs_mgr_free_fstab);
+ auto fsrec = static_cast<fstab_rec*>(calloc(1, sizeof(fstab_rec)));
+ local_fstab->num_entries = 1;
+ local_fstab->recs = fsrec;
+ fsrec->blk_device = strdup(device_path.c_str());
+ fsrec->mount_point = strdup(kScratchMountPoint.c_str());
+ fsrec->fs_type = strdup(mnt_type.c_str());
+ fsrec->flags = MS_RELATIME;
+ fsrec->fs_options = strdup("");
+ auto mounted = fs_mgr_do_mount_one(fsrec) == 0;
+ auto save_errno = errno;
+ setfscreatecon(nullptr);
+ if (!mounted) rmdir(kScratchMountPoint.c_str());
+ errno = save_errno;
+ return mounted;
+}
+
+const std::string kMkF2fs("/system/bin/make_f2fs");
+const std::string kMkExt4("/system/bin/mke2fs");
+
+std::string fs_mgr_overlayfs_scratch_mount_type() {
+ if (!access(kMkF2fs.c_str(), X_OK)) return "f2fs";
+ if (!access(kMkExt4.c_str(), X_OK)) return "ext4";
+ return "auto";
+}
+
+std::string fs_mgr_overlayfs_scratch_device() {
+ if (!scratch_device_cache.empty()) return scratch_device_cache;
+
+ auto& dm = DeviceMapper::Instance();
+ const auto partition_name = android::base::Basename(kScratchMountPoint);
+ std::string path;
+ if (!dm.GetDmDevicePathByName(partition_name, &path)) return "";
+ return scratch_device_cache = path;
+}
+
+// Create and mount kScratchMountPoint storage if we have logical partitions
+bool fs_mgr_overlayfs_setup_scratch(const fstab* fstab, bool* change) {
+ if (fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) return true;
+ auto mnt_type = fs_mgr_overlayfs_scratch_mount_type();
+ auto scratch_device = fs_mgr_overlayfs_scratch_device();
+ auto partition_exists = fs_mgr_rw_access(scratch_device);
+ if (!partition_exists) {
+ auto slot_number = fs_mgr_overlayfs_slot_number();
+ auto super_device = fs_mgr_overlayfs_super_device(slot_number);
+ if (!fs_mgr_rw_access(super_device)) return false;
+ if (!fs_mgr_overlayfs_has_logical(fstab)) return false;
+ auto builder = MetadataBuilder::New(super_device, slot_number);
+ if (!builder) {
+ PERROR << "open " << super_device << " metadata";
+ return false;
+ }
+ const auto partition_name = android::base::Basename(kScratchMountPoint);
+ partition_exists = builder->FindPartition(partition_name) != nullptr;
+ if (!partition_exists) {
+ auto partition = builder->AddPartition(partition_name, LP_PARTITION_ATTR_NONE);
+ if (!partition) {
+ PERROR << "create " << partition_name;
+ return false;
+ }
+ auto partition_size = builder->AllocatableSpace() - builder->UsedSpace();
+ // 512MB or half the remaining available space, whichever is greater.
+ partition_size = std::max(uint64_t(512 * 1024 * 1024), partition_size / 2);
+ if (!builder->ResizePartition(partition, partition_size)) {
+ PERROR << "resize " << partition_name;
+ return false;
+ }
+
+ auto metadata = builder->Export();
+ if (!metadata) {
+ LERROR << "generate new metadata " << partition_name;
+ return false;
+ }
+ if (!UpdatePartitionTable(super_device, *metadata.get(), slot_number)) {
+ LERROR << "update " << partition_name;
+ return false;
+ }
+
+ if (change) *change = true;
+ }
+
+ if (!CreateLogicalPartition(super_device, slot_number, partition_name, true, 0s,
+ &scratch_device))
+ return false;
+ }
+
+ if (partition_exists) {
+ if (fs_mgr_overlayfs_mount_scratch(scratch_device, mnt_type)) {
+ if (change) *change = true;
+ return true;
+ }
+ // partition existed, but was not initialized;
+ errno = 0;
+ }
+
+ auto ret = system((mnt_type == "f2fs")
+ ? ((kMkF2fs + " -d1 " + scratch_device).c_str())
+ : ((kMkExt4 + " -b 4096 -t ext4 -m 0 -M "s + kScratchMountPoint +
+ " -O has_journal " + scratch_device)
+ .c_str()));
+ if (ret) {
+ LERROR << "make " << mnt_type << " filesystem on " << scratch_device << " error=" << ret;
+ return false;
+ }
+
+ if (change) *change = true;
+
+ return fs_mgr_overlayfs_mount_scratch(scratch_device, mnt_type);
+}
+
+bool fs_mgr_overlayfs_scratch_can_be_mounted(const std::string& scratch_device) {
+ if (scratch_device.empty()) return false;
+ if (fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) return false;
+ if (fs_mgr_rw_access(scratch_device)) return true;
+ auto slot_number = fs_mgr_overlayfs_slot_number();
+ auto super_device = fs_mgr_overlayfs_super_device(slot_number);
+ if (!fs_mgr_rw_access(super_device)) return false;
+ auto builder = MetadataBuilder::New(super_device, slot_number);
+ if (!builder) return false;
+ return builder->FindPartition(android::base::Basename(kScratchMountPoint)) != nullptr;
+}
+
} // namespace
bool fs_mgr_overlayfs_mount_all(const fstab* fstab) {
@@ -513,14 +727,37 @@
if (!fstab) return ret;
+ auto scratch_can_be_mounted = true;
for (const auto& mount_point : fs_mgr_candidate_list(fstab)) {
if (fs_mgr_overlayfs_already_mounted(mount_point)) continue;
+ if (scratch_can_be_mounted) {
+ scratch_can_be_mounted = false;
+ auto scratch_device = fs_mgr_overlayfs_scratch_device();
+ if (fs_mgr_overlayfs_scratch_can_be_mounted(scratch_device) &&
+ fs_mgr_wait_for_file(scratch_device, 10s) &&
+ fs_mgr_overlayfs_mount_scratch(scratch_device,
+ fs_mgr_overlayfs_scratch_mount_type()) &&
+ !fs_mgr_access(kScratchMountPoint + kOverlayTopDir)) {
+ umount2(kScratchMountPoint.c_str(), MNT_DETACH);
+ rmdir(kScratchMountPoint.c_str());
+ }
+ }
if (fs_mgr_overlayfs_mount(mount_point)) ret = true;
}
return ret;
}
-std::vector<std::string> fs_mgr_overlayfs_required_devices(const fstab*) {
+std::vector<std::string> fs_mgr_overlayfs_required_devices(const fstab* fstab) {
+ if (fs_mgr_get_entry_for_mount_point(const_cast<struct fstab*>(fstab), kScratchMountPoint)) {
+ return {};
+ }
+
+ for (const auto& mount_point : fs_mgr_candidate_list(fstab)) {
+ if (fs_mgr_overlayfs_already_mounted(mount_point)) continue;
+ auto device = fs_mgr_overlayfs_scratch_device();
+ if (!fs_mgr_overlayfs_scratch_can_be_mounted(device)) break;
+ return {device};
+ }
return {};
}
@@ -529,10 +766,6 @@
bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool* change) {
if (change) *change = false;
auto ret = false;
- if (backing && (kOverlayMountPoint != backing)) {
- errno = EINVAL;
- return ret;
- }
if (!fs_mgr_wants_overlayfs()) return ret;
if (!fs_mgr_boot_completed()) {
errno = EBUSY;
@@ -542,16 +775,32 @@
std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),
fs_mgr_free_fstab);
- if (fstab && !fs_mgr_get_entry_for_mount_point(fstab.get(), kOverlayMountPoint)) return ret;
+ if (!fstab) return ret;
auto mounts = fs_mgr_candidate_list(fstab.get(), fs_mgr_mount_point(fstab.get(), mount_point));
- if (fstab && mounts.empty()) return ret;
+ if (mounts.empty()) return ret;
+
+ std::string dir;
+ for (const auto& overlay_mount_point : kOverlayMountPoints) {
+ if (backing && backing[0] && (overlay_mount_point != backing)) continue;
+ if (overlay_mount_point == kScratchMountPoint) {
+ if (!fs_mgr_rw_access(fs_mgr_overlayfs_super_device(fs_mgr_overlayfs_slot_number())) ||
+ !fs_mgr_overlayfs_has_logical(fstab.get())) {
+ continue;
+ }
+ if (!fs_mgr_overlayfs_setup_scratch(fstab.get(), change)) continue;
+ } else {
+ if (!fs_mgr_get_entry_for_mount_point(fstab.get(), overlay_mount_point)) continue;
+ }
+ dir = overlay_mount_point;
+ break;
+ }
+ if (dir.empty()) {
+ errno = ESRCH;
+ return ret;
+ }
std::string overlay;
- ret |= fs_mgr_overlayfs_setup_dir(kOverlayMountPoint, &overlay, change);
-
- if (!fstab && mount_point && fs_mgr_overlayfs_setup_one(overlay, mount_point, change)) {
- ret = true;
- }
+ ret |= fs_mgr_overlayfs_setup_dir(dir, &overlay, change);
for (const auto& fsrec_mount_point : mounts) {
ret |= fs_mgr_overlayfs_setup_one(overlay, fsrec_mount_point, change);
}
@@ -566,7 +815,10 @@
fs_mgr_read_fstab_default(), fs_mgr_free_fstab)
.get(),
mount_point);
- auto ret = fs_mgr_overlayfs_teardown_one(kOverlayMountPoint, mount_point ?: "", change);
+ auto ret = true;
+ for (const auto& overlay_mount_point : kOverlayMountPoints) {
+ ret &= fs_mgr_overlayfs_teardown_one(overlay_mount_point, mount_point ?: "", change);
+ }
if (!fs_mgr_wants_overlayfs()) {
// After obligatory teardown to make sure everything is clean, but if
// we didn't want overlayfs in the the first place, we do not want to