package org.eclipse.jgit.internal.storage.file;
+import static java.util.concurrent.TimeUnit.NANOSECONDS;
+import static java.util.concurrent.TimeUnit.SECONDS;
import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.LOCK_FAILURE;
import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.OK;
import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.REJECTED_MISSING_OBJECT;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeTrue;
import java.io.File;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
+import java.util.concurrent.locks.ReentrantLock;
import java.util.function.Predicate;
import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
}
}
+ @Test
+ public void atomicUpdateRespectsInProcessLock() throws Exception {
+ assumeTrue(atomic);
+
+ writeLooseRef("refs/heads/master", A);
+
+ List<ReceiveCommand> cmds = Arrays.asList(
+ new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
+ new ReceiveCommand(zeroId(), B, "refs/heads/branch", CREATE));
+
+ Thread t = new Thread(() -> {
+ try {
+ execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));
+ } catch (Exception e) {
+ throw new RuntimeException(e);
+ }
+ });
+
+ ReentrantLock l = refdir.inProcessPackedRefsLock;
+ l.lock();
+ try {
+ t.start();
+ long timeoutSecs = 10;
+ long startNanos = System.nanoTime();
+
+ // Hold onto the lock until we observe the worker thread has attempted to
+ // acquire it.
+ while (l.getQueueLength() == 0) {
+ long elapsedNanos = System.nanoTime() - startNanos;
+ assertTrue(
+ "timed out waiting for work thread to attempt to acquire lock",
+ NANOSECONDS.toSeconds(elapsedNanos) < timeoutSecs);
+ Thread.sleep(3);
+ }
+
+ // Once we unlock, the worker thread should finish the update promptly.
+ l.unlock();
+ t.join(SECONDS.toMillis(timeoutSecs));
+ assertFalse(t.isAlive());
+ } finally {
+ if (l.isHeldByCurrentThread()) {
+ l.unlock();
+ }
+ }
+
+ assertResults(cmds, OK, OK);
+ assertRefs(
+ "refs/heads/master", B,
+ "refs/heads/branch", B);
+ }
+
private void writeLooseRef(String name, AnyObjectId id) throws IOException {
write(new File(diskRepo.getDirectory(), name), id.name() + "\n");
}
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.ReentrantLock;
import org.eclipse.jgit.annotations.NonNull;
import org.eclipse.jgit.annotations.Nullable;
/** Immutable sorted list of packed references. */
final AtomicReference<PackedRefList> packedRefs = new AtomicReference<>();
+ /**
+ * Lock for coordinating operations within a single process that may contend
+ * on the {@code packed-refs} file.
+ * <p>
+ * All operations that write {@code packed-refs} must still acquire a
+ * {@link LockFile} on {@link #packedRefsFile}, even after they have acquired
+ * this lock, since there may be multiple {@link RefDirectory} instances or
+ * other processes operating on the same repo on disk.
+ * <p>
+ * This lock exists so multiple threads in the same process can wait in a fair
+ * queue without trying, failing, and retrying to acquire the on-disk lock. If
+ * {@code RepositoryCache} is used, this lock instance will be used by all
+ * threads.
+ */
+ final ReentrantLock inProcessPackedRefsLock = new ReentrantLock(true);
+
/**
* Number of modifications made to this database.
* <p>
// we don't miss an edit made externally.
final PackedRefList packed = getPackedRefs();
if (packed.contains(name)) {
- LockFile lck = lockPackedRefsOrThrow();
+ inProcessPackedRefsLock.lock();
try {
- PackedRefList cur = readPackedRefs();
- int idx = cur.find(name);
- if (0 <= idx)
- commitPackedRefs(lck, cur.remove(idx), packed);
+ LockFile lck = lockPackedRefsOrThrow();
+ try {
+ PackedRefList cur = readPackedRefs();
+ int idx = cur.find(name);
+ if (0 <= idx)
+ commitPackedRefs(lck, cur.remove(idx), packed);
+ } finally {
+ lck.unlock();
+ }
} finally {
- lck.unlock();
+ inProcessPackedRefsLock.unlock();
}
}
FS fs = parent.getFS();
// Lock the packed refs file and read the content
- LockFile lck = lockPackedRefsOrThrow();
-
+ inProcessPackedRefsLock.lock();
try {
- final PackedRefList packed = getPackedRefs();
- RefList<Ref> cur = readPackedRefs();
-
- // Iterate over all refs to be packed
- boolean dirty = false;
- for (String refName : refs) {
- Ref oldRef = readRef(refName, cur);
- if (oldRef == null) {
- continue; // A non-existent ref is already correctly packed.
- }
- if (oldRef.isSymbolic()) {
- continue; // can't pack symbolic refs
- }
- // Add/Update it to packed-refs
- Ref newRef = peeledPackedRef(oldRef);
- if (newRef == oldRef) {
- // No-op; peeledPackedRef returns the input ref only if it's already
- // packed, and readRef returns a packed ref only if there is no loose
- // ref.
- continue;
- }
+ LockFile lck = lockPackedRefsOrThrow();
+ try {
+ final PackedRefList packed = getPackedRefs();
+ RefList<Ref> cur = readPackedRefs();
+
+ // Iterate over all refs to be packed
+ boolean dirty = false;
+ for (String refName : refs) {
+ Ref oldRef = readRef(refName, cur);
+ if (oldRef == null) {
+ continue; // A non-existent ref is already correctly packed.
+ }
+ if (oldRef.isSymbolic()) {
+ continue; // can't pack symbolic refs
+ }
+ // Add/Update it to packed-refs
+ Ref newRef = peeledPackedRef(oldRef);
+ if (newRef == oldRef) {
+ // No-op; peeledPackedRef returns the input ref only if it's already
+ // packed, and readRef returns a packed ref only if there is no
+ // loose ref.
+ continue;
+ }
- dirty = true;
- int idx = cur.find(refName);
- if (idx >= 0) {
- cur = cur.set(idx, newRef);
- } else {
- cur = cur.add(idx, newRef);
+ dirty = true;
+ int idx = cur.find(refName);
+ if (idx >= 0) {
+ cur = cur.set(idx, newRef);
+ } else {
+ cur = cur.add(idx, newRef);
+ }
}
- }
- if (!dirty) {
- // All requested refs were already packed accurately
- return packed;
- }
-
- // The new content for packed-refs is collected. Persist it.
- PackedRefList result = commitPackedRefs(lck, cur, packed);
-
- // Now delete the loose refs which are now packed
- for (String refName : refs) {
- // Lock the loose ref
- File refFile = fileFor(refName);
- if (!fs.exists(refFile)) {
- continue;
+ if (!dirty) {
+ // All requested refs were already packed accurately
+ return packed;
}
- LockFile rLck = heldLocks.get(refName);
- boolean shouldUnlock;
- if (rLck == null) {
- rLck = new LockFile(refFile);
- if (!rLck.lock()) {
- continue;
- }
- shouldUnlock = true;
- } else {
- shouldUnlock = false;
- }
+ // The new content for packed-refs is collected. Persist it.
+ PackedRefList result = commitPackedRefs(lck, cur, packed);
- try {
- LooseRef currentLooseRef = scanRef(null, refName);
- if (currentLooseRef == null || currentLooseRef.isSymbolic()) {
+ // Now delete the loose refs which are now packed
+ for (String refName : refs) {
+ // Lock the loose ref
+ File refFile = fileFor(refName);
+ if (!fs.exists(refFile)) {
continue;
}
- Ref packedRef = cur.get(refName);
- ObjectId clr_oid = currentLooseRef.getObjectId();
- if (clr_oid != null
- && clr_oid.equals(packedRef.getObjectId())) {
- RefList<LooseRef> curLoose, newLoose;
- do {
- curLoose = looseRefs.get();
- int idx = curLoose.find(refName);
- if (idx < 0) {
- break;
- }
- newLoose = curLoose.remove(idx);
- } while (!looseRefs.compareAndSet(curLoose, newLoose));
- int levels = levelsIn(refName) - 2;
- delete(refFile, levels, rLck);
+
+ LockFile rLck = heldLocks.get(refName);
+ boolean shouldUnlock;
+ if (rLck == null) {
+ rLck = new LockFile(refFile);
+ if (!rLck.lock()) {
+ continue;
+ }
+ shouldUnlock = true;
+ } else {
+ shouldUnlock = false;
}
- } finally {
- if (shouldUnlock) {
- rLck.unlock();
+
+ try {
+ LooseRef currentLooseRef = scanRef(null, refName);
+ if (currentLooseRef == null || currentLooseRef.isSymbolic()) {
+ continue;
+ }
+ Ref packedRef = cur.get(refName);
+ ObjectId clr_oid = currentLooseRef.getObjectId();
+ if (clr_oid != null
+ && clr_oid.equals(packedRef.getObjectId())) {
+ RefList<LooseRef> curLoose, newLoose;
+ do {
+ curLoose = looseRefs.get();
+ int idx = curLoose.find(refName);
+ if (idx < 0) {
+ break;
+ }
+ newLoose = curLoose.remove(idx);
+ } while (!looseRefs.compareAndSet(curLoose, newLoose));
+ int levels = levelsIn(refName) - 2;
+ delete(refFile, levels, rLck);
+ }
+ } finally {
+ if (shouldUnlock) {
+ rLck.unlock();
+ }
}
}
+ // Don't fire refsChanged. The refs have not change, only their
+ // storage.
+ return result;
+ } finally {
+ lck.unlock();
}
- // Don't fire refsChanged. The refs have not change, only their
- // storage.
- return result;
} finally {
- lck.unlock();
+ inProcessPackedRefsLock.unlock();
}
}
projects / jgit.git / commitdiff