Merge "liblp: Force 10.0 metadata on downgrade to Q." into rvc-dev
diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index 2f516fa..5554f77 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -204,11 +204,18 @@
}
}
- if (IPropertyFetcher::GetInstance()->GetBoolProperty("ro.virtual_ab.enabled", false) &&
- !always_keep_source_slot) {
- if (!UpdateMetadataForInPlaceSnapshot(metadata.get(), source_slot_number,
- target_slot_number)) {
- return nullptr;
+ if (IPropertyFetcher::GetInstance()->GetBoolProperty("ro.virtual_ab.enabled", false)) {
+ if (always_keep_source_slot) {
+ // always_keep_source_slot implies the target build does not support snapshots.
+ // Clear unsupported attributes.
+ SetMetadataHeaderV0(metadata.get());
+ } else {
+ // !always_keep_source_slot implies the target build supports snapshots. Do snapshot
+ // updates.
+ if (!UpdateMetadataForInPlaceSnapshot(metadata.get(), source_slot_number,
+ target_slot_number)) {
+ return nullptr;
+ }
}
}
diff --git a/fs_mgr/liblp/include/liblp/builder.h b/fs_mgr/liblp/include/liblp/builder.h
index bd39150..6c7a707 100644
--- a/fs_mgr/liblp/include/liblp/builder.h
+++ b/fs_mgr/liblp/include/liblp/builder.h
@@ -209,8 +209,10 @@
// metadata may not have the target slot's devices listed yet, in which
// case, it is automatically upgraded to include all available block
// devices.
- // If |always_keep_source_slot| is set, on a Virtual A/B device, source slot
- // partitions are kept. This is useful when applying a downgrade package.
+ // If |always_keep_source_slot| is set, on a Virtual A/B device
+ // - source slot partitions are kept.
+ // - UPDATED flag is cleared.
+ // This is useful when applying a downgrade package.
static std::unique_ptr<MetadataBuilder> NewForUpdate(const IPartitionOpener& opener,
const std::string& source_partition,
uint32_t source_slot_number,
diff --git a/fs_mgr/liblp/utility.cpp b/fs_mgr/liblp/utility.cpp
index 48c5c83..d8e171b 100644
--- a/fs_mgr/liblp/utility.cpp
+++ b/fs_mgr/liblp/utility.cpp
@@ -15,6 +15,7 @@
*/
#include <fcntl.h>
+#include <inttypes.h>
#include <stdint.h>
#include <sys/stat.h>
#include <unistd.h>
@@ -29,6 +30,7 @@
#include <vector>
#include <android-base/file.h>
+#include <android-base/stringprintf.h>
#include <ext4_utils/ext4_utils.h>
#include <openssl/sha.h>
@@ -285,5 +287,42 @@
return true;
}
+inline std::string ToHexString(uint64_t value) {
+ return android::base::StringPrintf("0x%" PRIx64, value);
+}
+
+void SetMetadataHeaderV0(LpMetadata* metadata) {
+ if (metadata->header.minor_version <= LP_METADATA_MINOR_VERSION_MIN) {
+ return;
+ }
+ LINFO << "Forcefully setting metadata header version " << LP_METADATA_MAJOR_VERSION << "."
+ << metadata->header.minor_version << " to " << LP_METADATA_MAJOR_VERSION << "."
+ << LP_METADATA_MINOR_VERSION_MIN;
+ metadata->header.minor_version = LP_METADATA_MINOR_VERSION_MIN;
+ metadata->header.header_size = sizeof(LpMetadataHeaderV1_0);
+
+ // Retrofit Virtual A/B devices should have version 10.1, so flags shouldn't be set.
+ // Warn if this is the case, but zero it out anyways.
+ if (metadata->header.flags) {
+ LWARN << "Zeroing unexpected flags: " << ToHexString(metadata->header.flags);
+ }
+
+ // Zero out all fields beyond LpMetadataHeaderV0.
+ static_assert(sizeof(metadata->header) > sizeof(LpMetadataHeaderV1_0));
+ memset(reinterpret_cast<uint8_t*>(&metadata->header) + sizeof(LpMetadataHeaderV1_0), 0,
+ sizeof(metadata->header) - sizeof(LpMetadataHeaderV1_0));
+
+ // Clear partition attributes unknown to V0.
+ // On retrofit Virtual A/B devices, UPDATED flag may be set, so only log info here.
+ for (auto& partition : metadata->partitions) {
+ if (partition.attributes & ~LP_PARTITION_ATTRIBUTE_MASK_V0) {
+ LINFO << "Clearing " << GetPartitionName(partition)
+ << " partition attribute: " << ToHexString(partition.attributes);
+ }
+
+ partition.attributes &= LP_PARTITION_ATTRIBUTE_MASK_V0;
+ }
+}
+
} // namespace fs_mgr
} // namespace android
diff --git a/fs_mgr/liblp/utility.h b/fs_mgr/liblp/utility.h
index 0661769..1d86edd 100644
--- a/fs_mgr/liblp/utility.h
+++ b/fs_mgr/liblp/utility.h
@@ -103,6 +103,10 @@
bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot_number,
uint32_t target_slot_number);
+// Forcefully set metadata header version to 1.0, clearing any incompatible flags and attributes
+// so that when downgrading to a build with liblp V0, the device still boots.
+void SetMetadataHeaderV0(LpMetadata* metadata);
+
} // namespace fs_mgr
} // namespace android