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snapuserd: Sort REPLACE ops for batch merge

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Since we will be iterating forward for user-space
merge, we need to sort the blocks in increasing order
so that blocks can be batch merged if contiguous.

For dm-snapshot merging, we will continue to sort
in decreasing order.

Bug: 193863397
Test: Snapuserd_test
Signed-off-by: Akilesh Kailash <akailash@google.com>
Change-Id: I25fb5fce054f716a2ad0dddc0d0c3afef18bc7ad
This commit is contained in:
Akilesh Kailash 2021-08-17 23:42:16 +00:00
parent b94353cae0
commit 2ba8eea489
3 changed files with 25 additions and 6 deletions
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21
fs_mgr/libsnapshot/cow_reader.cpp
View file

@ -34,11 +34,12 @@
namespace android {
namespace snapshot {
CowReader::CowReader()
CowReader::CowReader(ReaderFlags reader_flag)
: fd_(-1),
header_(),
fd_size_(0),
merge_op_blocks_(std::make_shared<std::vector<uint32_t>>()) {}
merge_op_blocks_(std::make_shared<std::vector<uint32_t>>()),
reader_flag_(reader_flag) {}
static void SHA256(const void*, size_t, uint8_t[]) {
#if 0
@ -415,7 +416,7 @@ bool CowReader::ParseOps(std::optional<uint64_t> label) {
//==============================================================
bool CowReader::PrepMergeOps() {
auto merge_op_blocks = std::make_shared<std::vector<uint32_t>>();
std::set<int, std::greater<int>> other_ops;
std::vector<int> other_ops;
auto seq_ops_set = std::unordered_set<uint32_t>();
auto block_map = std::make_shared<std::unordered_map<uint32_t, int>>();
size_t num_seqs = 0;
@ -446,7 +447,7 @@ bool CowReader::PrepMergeOps() {
if (!has_seq_ops_ && IsOrderedOp(current_op)) {
merge_op_blocks->emplace_back(current_op.new_block);
} else if (seq_ops_set.count(current_op.new_block) == 0) {
other_ops.insert(current_op.new_block);
other_ops.push_back(current_op.new_block);
}
block_map->insert({current_op.new_block, i});
}
@ -462,6 +463,18 @@ bool CowReader::PrepMergeOps() {
} else {
num_ordered_ops_to_merge_ = 0;
}
// Sort the vector in increasing order if merging in user-space as
// we can batch merge them when iterating from forward.
//
// dm-snapshot-merge requires decreasing order as we iterate the blocks
// in reverse order.
if (reader_flag_ == ReaderFlags::USERSPACE_MERGE) {
std::sort(other_ops.begin(), other_ops.end());
} else {
std::sort(other_ops.begin(), other_ops.end(), std::greater<int>());
}
merge_op_blocks->reserve(merge_op_blocks->size() + other_ops.size());
for (auto block : other_ops) {
merge_op_blocks->emplace_back(block);

8
fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
View file

@ -104,7 +104,12 @@ class ICowOpIter {
class CowReader final : public ICowReader {
public:
CowReader();
enum class ReaderFlags {
DEFAULT = 0,
USERSPACE_MERGE = 1,
};
CowReader(ReaderFlags reader_flag = ReaderFlags::DEFAULT);
~CowReader() { owned_fd_ = {}; }
// Parse the COW, optionally, up to the given label. If no label is
@ -166,6 +171,7 @@ class CowReader final : public ICowReader {
uint64_t num_ordered_ops_to_merge_;
bool has_seq_ops_;
std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc_;
ReaderFlags reader_flag_;
};
} // namespace snapshot

2
fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp
View file

@ -139,7 +139,7 @@ void SnapshotHandler::CheckMergeCompletionStatus() {
}
bool SnapshotHandler::ReadMetadata() {
reader_ = std::make_unique<CowReader>();
reader_ = std::make_unique<CowReader>(CowReader::ReaderFlags::USERSPACE_MERGE);
CowHeader header;
CowOptions options;