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Resolving race condition while writing recent taskids

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am: fd0bd4f39d

Change-Id: I2bfd5c68c6a5a9989a9dab6038313a5d5849b765
This commit is contained in:
Suprabh Shukla
2016-08-26 00:47:27 +00:00
committed by android-build-merger
parent 1167bcf2c9 fd0bd4f39d
commit c9e7c49def
2 changed files with 49 additions and 40 deletions
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87
services/core/java/com/android/server/am/TaskPersister.java
View File

@@ -87,6 +87,8 @@ public class TaskPersister {
private final RecentTasks mRecentTasks;
private final SparseArray<SparseBooleanArray> mTaskIdsInFile = new SparseArray<>();
private final File mTaskIdsDir;
// To lock file operations in TaskPersister
private final Object mIoLock = new Object();
/**
* Value determines write delay mode as follows: < 0 We are Flushing. No delays between writes
@@ -195,52 +197,52 @@ public class TaskPersister {
return mTaskIdsInFile.get(userId).clone();
}
final SparseBooleanArray persistedTaskIds = new SparseBooleanArray();
BufferedReader reader = null;
String line;
try {
reader = new BufferedReader(new FileReader(getUserPersistedTaskIdsFile(userId)));
while ((line = reader.readLine()) != null) {
for (String taskIdString : line.split("\\s+")) {
int id = Integer.parseInt(taskIdString);
persistedTaskIds.put(id, true);
synchronized (mIoLock) {
BufferedReader reader = null;
String line;
try {
reader = new BufferedReader(new FileReader(getUserPersistedTaskIdsFile(userId)));
while ((line = reader.readLine()) != null) {
for (String taskIdString : line.split("\\s+")) {
int id = Integer.parseInt(taskIdString);
persistedTaskIds.put(id, true);
}
}
} catch (FileNotFoundException e) {
// File doesn't exist. Ignore.
} catch (Exception e) {
Slog.e(TAG, "Error while reading taskIds file for user " + userId, e);
} finally {
IoUtils.closeQuietly(reader);
}
} catch (FileNotFoundException e) {
// File doesn't exist. Ignore.
} catch (Exception e) {
Slog.e(TAG, "Error while reading taskIds file for user " + userId, e);
} finally {
IoUtils.closeQuietly(reader);
}
mTaskIdsInFile.put(userId, persistedTaskIds);
return persistedTaskIds.clone();
}
@VisibleForTesting
void maybeWritePersistedTaskIdsForUser(@NonNull SparseBooleanArray taskIds, int userId) {
void writePersistedTaskIdsForUser(@NonNull SparseBooleanArray taskIds, int userId) {
if (userId < 0) {
return;
}
SparseBooleanArray persistedIdsInFile = mTaskIdsInFile.get(userId);
if (persistedIdsInFile != null && persistedIdsInFile.equals(taskIds)) {
return;
}
final File persistedTaskIdsFile = getUserPersistedTaskIdsFile(userId);
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter(persistedTaskIdsFile));
for (int i = 0; i < taskIds.size(); i++) {
if (taskIds.valueAt(i)) {
writer.write(String.valueOf(taskIds.keyAt(i)));
writer.newLine();
synchronized (mIoLock) {
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter(persistedTaskIdsFile));
for (int i = 0; i < taskIds.size(); i++) {
if (taskIds.valueAt(i)) {
writer.write(String.valueOf(taskIds.keyAt(i)));
writer.newLine();
}
}
} catch (Exception e) {
Slog.e(TAG, "Error while writing taskIds file for user " + userId, e);
} finally {
IoUtils.closeQuietly(writer);
}
} catch (Exception e) {
Slog.e(TAG, "Error while writing taskIds file for user " + userId, e);
} finally {
IoUtils.closeQuietly(writer);
}
mTaskIdsInFile.put(userId, taskIds.clone());
}
void unloadUserDataFromMemory(int userId) {
@@ -543,16 +545,23 @@ public class TaskPersister {
}
private void writeTaskIdsFiles() {
int candidateUserIds[];
SparseArray<SparseBooleanArray> changedTaskIdsPerUser = new SparseArray<>();
synchronized (mService) {
candidateUserIds = mRecentTasks.usersWithRecentsLoadedLocked();
}
SparseBooleanArray taskIdsToSave;
for (int userId : candidateUserIds) {
synchronized (mService) {
taskIdsToSave = mRecentTasks.mPersistedTaskIds.get(userId).clone();
for (int userId : mRecentTasks.usersWithRecentsLoadedLocked()) {
SparseBooleanArray taskIdsToSave = mRecentTasks.mPersistedTaskIds.get(userId);
SparseBooleanArray persistedIdsInFile = mTaskIdsInFile.get(userId);
if (persistedIdsInFile != null && persistedIdsInFile.equals(taskIdsToSave)) {
continue;
} else {
SparseBooleanArray taskIdsToSaveCopy = taskIdsToSave.clone();
mTaskIdsInFile.put(userId, taskIdsToSaveCopy);
changedTaskIdsPerUser.put(userId, taskIdsToSaveCopy);
}
}
maybeWritePersistedTaskIdsForUser(taskIdsToSave, userId);
}
for (int i = 0; i < changedTaskIdsPerUser.size(); i++) {
writePersistedTaskIdsForUser(changedTaskIdsPerUser.valueAt(i),
changedTaskIdsPerUser.keyAt(i));
}
}

2
services/tests/servicestests/src/com/android/server/am/TaskPersisterTest.java
View File

@@ -62,7 +62,7 @@ public class TaskPersisterTest extends AndroidTestCase {
for (int i = 0; i < 100; i++) {
taskIdsOnFile.put(getRandomTaskIdForUser(testUserId), true);
}
mTaskPersister.maybeWritePersistedTaskIdsForUser(taskIdsOnFile, testUserId);
mTaskPersister.writePersistedTaskIdsForUser(taskIdsOnFile, testUserId);
SparseBooleanArray newTaskIdsOnFile = mTaskPersister
.loadPersistedTaskIdsForUser(testUserId);
assertTrue("TaskIds written differ from TaskIds read back from file",