commit 480ca04eabdc4678e435ebc201a542c0709a28bc
author Alessio Balsini <balsini@google.com> Tue Jan 07 17:43:20 2020 +0000
committer Alessio Balsini <balsini@google.com> Wed Jan 15 16:32:37 2020 +0000
tree c1414562269ed25d646d3d7456641f331fb4d5ac
parent b696585b1bd9ff24207f99d1d0eb8fb8a26b14b7

Snapshot merge progress percentage

Compute and print the progress percentage of the dm-snapshot devices
merging after an update is marked as successful.
All the snapshot devices are queried for their update states and all
their allocated, metadata and total sectors are summed as if the system
consists of a single big snapshot device, as well as the initial
allocated sectors to keep trace of the absolute progress. Then the merge
percentage is computed on the numbers for this fake snapshot device.

Bug: 139088917
Test: manual OTA
Change-Id: Ia9a51742105c90b7fd043f3cbf4249877def7f08
Signed-off-by: Alessio Balsini <balsini@google.com>

fs_mgr/libsnapshot/snapshot.cpp

diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 70a69a5..b84d873 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -1249,15 +1249,45 @@
         return UpdateState::None;
     }
 
-    auto state = ReadUpdateState(lock.get());
-    if (progress) {
-        *progress = 0.0;
-        if (state == UpdateState::Merging) {
-            // :TODO: When merging is implemented, set progress_val.
-        } else if (state == UpdateState::MergeCompleted) {
-            *progress = 100.0;
-        }
+    SnapshotUpdateStatus update_status = ReadSnapshotUpdateStatus(lock.get());
+    auto state = update_status.state();
+    if (progress == nullptr) {
+        return state;
     }
+
+    if (state == UpdateState::MergeCompleted) {
+        *progress = 100.0;
+        return state;
+    }
+
+    *progress = 0.0;
+    if (state != UpdateState::Merging) {
+        return state;
+    }
+
+    // Sum all the snapshot states as if the system consists of a single huge
+    // snapshots device, then compute the merge completion percentage of that
+    // device.
+    std::vector<std::string> snapshots;
+    if (!ListSnapshots(lock.get(), &snapshots)) {
+        LOG(ERROR) << "Could not list snapshots";
+        return state;
+    }
+
+    DmTargetSnapshot::Status fake_snapshots_status = {};
+    for (const auto& snapshot : snapshots) {
+        DmTargetSnapshot::Status current_status;
+
+        if (!QuerySnapshotStatus(snapshot, nullptr, &current_status)) continue;
+
+        fake_snapshots_status.sectors_allocated += current_status.sectors_allocated;
+        fake_snapshots_status.total_sectors += current_status.total_sectors;
+        fake_snapshots_status.metadata_sectors += current_status.metadata_sectors;
+    }
+
+    *progress = DmTargetSnapshot::MergePercent(fake_snapshots_status,
+                                               update_status.sectors_allocated());
+
     return state;
 }
 
@@ -2286,9 +2316,19 @@
         }
     }
 
+    unsigned int last_progress = 0;
+    auto callback = [&]() -> void {
+        double progress;
+        GetUpdateState(&progress);
+        if (last_progress < static_cast<unsigned int>(progress)) {
+            last_progress = progress;
+            LOG(INFO) << "Waiting for merge to complete: " << last_progress << "%.";
+        }
+    };
+
     LOG(INFO) << "Waiting for any previous merge request to complete. "
               << "This can take up to several minutes.";
-    auto state = ProcessUpdateState();
+    auto state = ProcessUpdateState(callback);
     if (state == UpdateState::None) {
         LOG(INFO) << "Can't find any snapshot to merge.";
         return state;
@@ -2300,7 +2340,8 @@
         }
         // All other states can be handled by ProcessUpdateState.
         LOG(INFO) << "Waiting for merge to complete. This can take up to several minutes.";
-        state = ProcessUpdateState();
+        last_progress = 0;
+        state = ProcessUpdateState(callback);
     }
 
     LOG(INFO) << "Merge finished with state \"" << state << "\".";