1 files changed, 221 insertions, 179 deletions

diff --git a/refs/files-backend.c b/refs/files-backend.c
index da8a986697..b956215bfc 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -12,7 +12,7 @@
 
 struct ref_lock {
 	char *ref_name;
-	struct lock_file *lk;
+	struct lock_file lk;
 	struct object_id old_oid;
 };
 
@@ -106,15 +106,6 @@ static void files_reflog_path(struct files_ref_store *refs,
 			      struct strbuf *sb,
 			      const char *refname)
 {
-	if (!refname) {
-		/*
-		 * FIXME: of course this is wrong in multi worktree
-		 * setting. To be fixed real soon.
-		 */
-		strbuf_addf(sb, "%s/logs", refs->gitcommondir);
-		return;
-	}
-
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
@@ -198,7 +189,7 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
 			if (!refs_resolve_ref_unsafe(&refs->base,
 						     refname.buf,
 						     RESOLVE_REF_READING,
-						     oid.hash, &flag)) {
+						     &oid, &flag)) {
 				oidclr(&oid);
 				flag |= REF_ISBROKEN;
 			} else if (is_null_oid(&oid)) {
@@ -270,7 +261,7 @@ static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
 }
 
 static int files_read_raw_ref(struct ref_store *ref_store,
-			      const char *refname, unsigned char *sha1,
+			      const char *refname, struct object_id *oid,
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
@@ -279,6 +270,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
 	const char *buf;
+	const char *p;
 	struct stat st;
 	int fd;
 	int ret = -1;
@@ -313,7 +305,7 @@ stat_ref:
 		if (errno != ENOENT)
 			goto out;
 		if (refs_read_raw_ref(refs->packed_ref_store, refname,
-				      sha1, referent, type)) {
+				      oid, referent, type)) {
 			errno = ENOENT;
 			goto out;
 		}
@@ -353,7 +345,7 @@ stat_ref:
 		 * packed ref:
 		 */
 		if (refs_read_raw_ref(refs->packed_ref_store, refname,
-				      sha1, referent, type)) {
+				      oid, referent, type)) {
 			errno = EISDIR;
 			goto out;
 		}
@@ -399,8 +391,8 @@ stat_ref:
 	 * Please note that FETCH_HEAD has additional
 	 * data after the sha.
 	 */
-	if (get_sha1_hex(buf, sha1) ||
-	    (buf[40] != '\0' && !isspace(buf[40]))) {
+	if (parse_oid_hex(buf, oid, &p) ||
+	    (*p != '\0' && !isspace(*p))) {
 		*type |= REF_ISBROKEN;
 		errno = EINVAL;
 		goto out;
@@ -418,9 +410,7 @@ out:
 
 static void unlock_ref(struct ref_lock *lock)
 {
-	/* Do not free lock->lk -- atexit() still looks at them */
-	if (lock->lk)
-		rollback_lock_file(lock->lk);
+	rollback_lock_file(&lock->lk);
 	free(lock->ref_name);
 	free(lock);
 }
@@ -534,11 +524,8 @@ retry:
 		goto error_return;
 	}
 
-	if (!lock->lk)
-		lock->lk = xcalloc(1, sizeof(struct lock_file));
-
 	if (hold_lock_file_for_update_timeout(
-			    lock->lk, ref_file.buf, LOCK_NO_DEREF,
+			    &lock->lk, ref_file.buf, LOCK_NO_DEREF,
 			    get_files_ref_lock_timeout_ms()) < 0) {
 		if (errno == ENOENT && --attempts_remaining > 0) {
 			/*
@@ -559,7 +546,7 @@ retry:
 	 */
 
 	if (files_read_raw_ref(&refs->base, refname,
-			       lock->old_oid.hash, referent, type)) {
+			       &lock->old_oid, referent, type)) {
 		if (errno == ENOENT) {
 			if (mustexist) {
 				/* Garden variety missing reference. */
@@ -655,43 +642,6 @@ out:
 	return ret;
 }
 
-static int files_peel_ref(struct ref_store *ref_store,
-			  const char *refname, unsigned char *sha1)
-{
-	struct files_ref_store *refs =
-		files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
-			       "peel_ref");
-	int flag;
-	unsigned char base[20];
-
-	if (current_ref_iter && current_ref_iter->refname == refname) {
-		struct object_id peeled;
-
-		if (ref_iterator_peel(current_ref_iter, &peeled))
-			return -1;
-		hashcpy(sha1, peeled.hash);
-		return 0;
-	}
-
-	if (refs_read_ref_full(ref_store, refname,
-			       RESOLVE_REF_READING, base, &flag))
-		return -1;
-
-	/*
-	 * If the reference is packed, read its ref_entry from the
-	 * cache in the hope that we already know its peeled value.
-	 * We only try this optimization on packed references because
-	 * (a) forcing the filling of the loose reference cache could
-	 * be expensive and (b) loose references anyway usually do not
-	 * have REF_KNOWS_PEELED.
-	 */
-	if (flag & REF_ISPACKED &&
-	    !refs_peel_ref(refs->packed_ref_store, refname, sha1))
-		return 0;
-
-	return peel_object(base, sha1);
-}
-
 struct files_ref_iterator {
 	struct ref_iterator base;
 
@@ -762,7 +712,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 		const char *prefix, unsigned int flags)
 {
 	struct files_ref_store *refs;
-	struct ref_iterator *loose_iter, *packed_iter;
+	struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
 	struct files_ref_iterator *iter;
 	struct ref_iterator *ref_iterator;
 	unsigned int required_flags = REF_STORE_READ;
@@ -772,10 +722,6 @@ static struct ref_iterator *files_ref_iterator_begin(
 
 	refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
 
-	iter = xcalloc(1, sizeof(*iter));
-	ref_iterator = &iter->base;
-	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
-
 	/*
 	 * We must make sure that all loose refs are read before
 	 * accessing the packed-refs file; this avoids a race
@@ -811,28 +757,34 @@ static struct ref_iterator *files_ref_iterator_begin(
 			refs->packed_ref_store, prefix, 0,
 			DO_FOR_EACH_INCLUDE_BROKEN);
 
-	iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
+	overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
+
+	iter = xcalloc(1, sizeof(*iter));
+	ref_iterator = &iter->base;
+	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
+			       overlay_iter->ordered);
+	iter->iter0 = overlay_iter;
 	iter->flags = flags;
 
 	return ref_iterator;
 }
 
 /*
- * Verify that the reference locked by lock has the value old_sha1.
- * Fail if the reference doesn't exist and mustexist is set. Return 0
- * on success. On error, write an error message to err, set errno, and
- * return a negative value.
+ * Verify that the reference locked by lock has the value old_oid
+ * (unless it is NULL).  Fail if the reference doesn't exist and
+ * mustexist is set. Return 0 on success. On error, write an error
+ * message to err, set errno, and return a negative value.
  */
 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
-		       const unsigned char *old_sha1, int mustexist,
+		       const struct object_id *old_oid, int mustexist,
 		       struct strbuf *err)
 {
 	assert(err);
 
 	if (refs_read_ref_full(ref_store, lock->ref_name,
 			       mustexist ? RESOLVE_REF_READING : 0,
-			       lock->old_oid.hash, NULL)) {
-		if (old_sha1) {
+			       &lock->old_oid, NULL)) {
+		if (old_oid) {
 			int save_errno = errno;
 			strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
 			errno = save_errno;
@@ -842,11 +794,11 @@ static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
 			return 0;
 		}
 	}
-	if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
+	if (old_oid && oidcmp(&lock->old_oid, old_oid)) {
 		strbuf_addf(err, "ref '%s' is at %s but expected %s",
 			    lock->ref_name,
 			    oid_to_hex(&lock->old_oid),
-			    sha1_to_hex(old_sha1));
+			    oid_to_hex(old_oid));
 		errno = EBUSY;
 		return -1;
 	}
@@ -876,22 +828,22 @@ static int create_reflock(const char *path, void *cb)
  * Locks a ref returning the lock on success and NULL on failure.
  * On failure errno is set to something meaningful.
  */
-static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
-					    const char *refname,
-					    const unsigned char *old_sha1,
-					    const struct string_list *extras,
-					    const struct string_list *skip,
-					    unsigned int flags, int *type,
-					    struct strbuf *err)
+static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
+					   const char *refname,
+					   const struct object_id *old_oid,
+					   const struct string_list *extras,
+					   const struct string_list *skip,
+					   unsigned int flags, int *type,
+					   struct strbuf *err)
 {
 	struct strbuf ref_file = STRBUF_INIT;
 	struct ref_lock *lock;
 	int last_errno = 0;
-	int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
+	int mustexist = (old_oid && !is_null_oid(old_oid));
 	int resolve_flags = RESOLVE_REF_NO_RECURSE;
 	int resolved;
 
-	files_assert_main_repository(refs, "lock_ref_sha1_basic");
+	files_assert_main_repository(refs, "lock_ref_oid_basic");
 	assert(err);
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
@@ -904,7 +856,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	files_ref_path(refs, &ref_file, refname);
 	resolved = !!refs_resolve_ref_unsafe(&refs->base,
 					     refname, resolve_flags,
-					     lock->old_oid.hash, type);
+					     &lock->old_oid, type);
 	if (!resolved && errno == EISDIR) {
 		/*
 		 * we are trying to lock foo but we used to
@@ -923,7 +875,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 		}
 		resolved = !!refs_resolve_ref_unsafe(&refs->base,
 						     refname, resolve_flags,
-						     lock->old_oid.hash, type);
+						     &lock->old_oid, type);
 	}
 	if (!resolved) {
 		last_errno = errno;
@@ -949,17 +901,15 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 		goto error_return;
 	}
 
-	lock->lk = xcalloc(1, sizeof(struct lock_file));
-
 	lock->ref_name = xstrdup(refname);
 
-	if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
+	if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
 		last_errno = errno;
 		unable_to_lock_message(ref_file.buf, errno, err);
 		goto error_return;
 	}
 
-	if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
+	if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
 		last_errno = errno;
 		goto error_return;
 	}
@@ -977,7 +927,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 
 struct ref_to_prune {
 	struct ref_to_prune *next;
-	unsigned char sha1[20];
+	struct object_id oid;
 	char name[FLEX_ARRAY];
 };
 
@@ -1045,7 +995,7 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 
 	transaction = ref_store_transaction_begin(&refs->base, &err);
 	if (!transaction ||
-	    ref_transaction_delete(transaction, r->name, r->sha1,
+	    ref_transaction_delete(transaction, r->name, &r->oid,
 				   REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
@@ -1130,7 +1080,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 		 * packed-refs transaction:
 		 */
 		if (ref_transaction_update(transaction, iter->refname,
-					   iter->oid->hash, NULL,
+					   iter->oid, NULL,
 					   REF_NODEREF, NULL, &err))
 			die("failure preparing to create packed reference %s: %s",
 			    iter->refname, err.buf);
@@ -1139,7 +1089,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 		if ((flags & PACK_REFS_PRUNE)) {
 			struct ref_to_prune *n;
 			FLEX_ALLOC_STR(n, name, iter->refname);
-			hashcpy(n->sha1, iter->oid->hash);
+			oidcpy(&n->oid, iter->oid);
 			n->next = refs_to_prune;
 			refs_to_prune = n;
 		}
@@ -1274,9 +1224,9 @@ static int commit_ref_update(struct files_ref_store *refs,
 			     const struct object_id *oid, const char *logmsg,
 			     struct strbuf *err);
 
-static int files_rename_ref(struct ref_store *ref_store,
+static int files_copy_or_rename_ref(struct ref_store *ref_store,
 			    const char *oldrefname, const char *newrefname,
-			    const char *logmsg)
+			    const char *logmsg, int copy)
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
@@ -1302,14 +1252,18 @@ static int files_rename_ref(struct ref_store *ref_store,
 
 	if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
 				     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				orig_oid.hash, &flag)) {
+				&orig_oid, &flag)) {
 		ret = error("refname %s not found", oldrefname);
 		goto out;
 	}
 
 	if (flag & REF_ISSYMREF) {
-		ret = error("refname %s is a symbolic ref, renaming it is not supported",
-			    oldrefname);
+		if (copy)
+			ret = error("refname %s is a symbolic ref, copying it is not supported",
+				    oldrefname);
+		else
+			ret = error("refname %s is a symbolic ref, renaming it is not supported",
+				    oldrefname);
 		goto out;
 	}
 	if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
@@ -1317,14 +1271,20 @@ static int files_rename_ref(struct ref_store *ref_store,
 		goto out;
 	}
 
-	if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
+	if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
 		ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
 			    oldrefname, strerror(errno));
 		goto out;
 	}
 
-	if (refs_delete_ref(&refs->base, logmsg, oldrefname,
-			    orig_oid.hash, REF_NODEREF)) {
+	if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
+		ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
+			    oldrefname, strerror(errno));
+		goto out;
+	}
+
+	if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
+			    &orig_oid, REF_NODEREF)) {
 		error("unable to delete old %s", oldrefname);
 		goto rollback;
 	}
@@ -1336,9 +1296,9 @@ static int files_rename_ref(struct ref_store *ref_store,
 	 * the safety anyway; we want to delete the reference whatever
 	 * its current value.
 	 */
-	if (!refs_read_ref_full(&refs->base, newrefname,
+	if (!copy && !refs_read_ref_full(&refs->base, newrefname,
 				RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				oid.hash, NULL) &&
+				&oid, NULL) &&
 	    refs_delete_ref(&refs->base, NULL, newrefname,
 			    NULL, REF_NODEREF)) {
 		if (errno == EISDIR) {
@@ -1364,10 +1324,13 @@ static int files_rename_ref(struct ref_store *ref_store,
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
-				   REF_NODEREF, NULL, &err);
+	lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
+				  REF_NODEREF, NULL, &err);
 	if (!lock) {
-		error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+		if (copy)
+			error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+		else
+			error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
 		strbuf_release(&err);
 		goto rollback;
 	}
@@ -1384,8 +1347,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 	goto out;
 
  rollback:
-	lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
-				   REF_NODEREF, NULL, &err);
+	lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
+				  REF_NODEREF, NULL, &err);
 	if (!lock) {
 		error("unable to lock %s for rollback: %s", oldrefname, err.buf);
 		strbuf_release(&err);
@@ -1418,16 +1381,32 @@ static int files_rename_ref(struct ref_store *ref_store,
 	return ret;
 }
 
-static int close_ref(struct ref_lock *lock)
+static int files_rename_ref(struct ref_store *ref_store,
+			    const char *oldrefname, const char *newrefname,
+			    const char *logmsg)
 {
-	if (close_lock_file(lock->lk))
+	return files_copy_or_rename_ref(ref_store, oldrefname,
+				 newrefname, logmsg, 0);
+}
+
+static int files_copy_ref(struct ref_store *ref_store,
+			    const char *oldrefname, const char *newrefname,
+			    const char *logmsg)
+{
+	return files_copy_or_rename_ref(ref_store, oldrefname,
+				 newrefname, logmsg, 1);
+}
+
+static int close_ref_gently(struct ref_lock *lock)
+{
+	if (close_lock_file_gently(&lock->lk))
 		return -1;
 	return 0;
 }
 
 static int commit_ref(struct ref_lock *lock)
 {
-	char *path = get_locked_file_path(lock->lk);
+	char *path = get_locked_file_path(&lock->lk);
 	struct stat st;
 
 	if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
@@ -1451,7 +1430,7 @@ static int commit_ref(struct ref_lock *lock)
 		free(path);
 	}
 
-	if (commit_lock_file(lock->lk))
+	if (commit_lock_file(&lock->lk))
 		return -1;
 	return 0;
 }
@@ -1565,7 +1544,7 @@ static int log_ref_write_fd(int fd, const struct object_id *old_oid,
 
 	written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
 	free(logrec);
-	if (written != len)
+	if (written < 0)
 		return -1;
 
 	return 0;
@@ -1643,12 +1622,12 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
 		unlock_ref(lock);
 		return -1;
 	}
-	fd = get_lock_file_fd(lock->lk);
-	if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
-	    write_in_full(fd, &term, 1) != 1 ||
-	    close_ref(lock) < 0) {
+	fd = get_lock_file_fd(&lock->lk);
+	if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) < 0 ||
+	    write_in_full(fd, &term, 1) < 0 ||
+	    close_ref_gently(lock) < 0) {
 		strbuf_addf(err,
-			    "couldn't write '%s'", get_lock_file_path(lock->lk));
+			    "couldn't write '%s'", get_lock_file_path(&lock->lk));
 		unlock_ref(lock);
 		return -1;
 	}
@@ -1692,13 +1671,12 @@ static int commit_ref_update(struct files_ref_store *refs,
 		 * check with HEAD only which should cover 99% of all usage
 		 * scenarios (even 100% of the default ones).
 		 */
-		struct object_id head_oid;
 		int head_flag;
 		const char *head_ref;
 
 		head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
 						   RESOLVE_REF_READING,
-						   head_oid.hash, &head_flag);
+						   NULL, &head_flag);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
@@ -1725,7 +1703,7 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 {
 	int ret = -1;
 #ifndef NO_SYMLINK_HEAD
-	char *ref_path = get_locked_file_path(lock->lk);
+	char *ref_path = get_locked_file_path(&lock->lk);
 	unlink(ref_path);
 	ret = symlink(target, ref_path);
 	free(ref_path);
@@ -1744,7 +1722,7 @@ static void update_symref_reflog(struct files_ref_store *refs,
 	struct object_id new_oid;
 	if (logmsg &&
 	    !refs_read_ref_full(&refs->base, target,
-				RESOLVE_REF_READING, new_oid.hash, NULL) &&
+				RESOLVE_REF_READING, &new_oid, NULL) &&
 	    files_log_ref_write(refs, refname, &lock->old_oid,
 				&new_oid, logmsg, 0, &err)) {
 		error("%s", err.buf);
@@ -1761,14 +1739,14 @@ static int create_symref_locked(struct files_ref_store *refs,
 		return 0;
 	}
 
-	if (!fdopen_lock_file(lock->lk, "w"))
+	if (!fdopen_lock_file(&lock->lk, "w"))
 		return error("unable to fdopen %s: %s",
-			     lock->lk->tempfile.filename.buf, strerror(errno));
+			     lock->lk.tempfile->filename.buf, strerror(errno));
 
 	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
-	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
+	fprintf(lock->lk.tempfile->fp, "ref: %s\n", target);
 	if (commit_ref(lock) < 0)
 		return error("unable to write symref for %s: %s", refname,
 			     strerror(errno));
@@ -1785,9 +1763,9 @@ static int files_create_symref(struct ref_store *ref_store,
 	struct ref_lock *lock;
 	int ret;
 
-	lock = lock_ref_sha1_basic(refs, refname, NULL,
-				   NULL, NULL, REF_NODEREF, NULL,
-				   &err);
+	lock = lock_ref_oid_basic(refs, refname, NULL,
+				  NULL, NULL, REF_NODEREF, NULL,
+				  &err);
 	if (!lock) {
 		error("%s", err.buf);
 		strbuf_release(&err);
@@ -2033,7 +2011,7 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 
 		if (refs_read_ref_full(iter->ref_store,
 				       diter->relative_path, 0,
-				       iter->oid.hash, &flags)) {
+				       &iter->oid, &flags)) {
 			error("bad ref for %s", diter->path.buf);
 			continue;
 		}
@@ -2075,23 +2053,64 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 	files_reflog_iterator_abort
 };
 
-static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
+static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
+						  const char *gitdir)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, REF_STORE_READ,
-			       "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
 
-	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	files_reflog_path(refs, &sb, NULL);
+	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
+	strbuf_addf(&sb, "%s/logs", gitdir);
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
 	iter->ref_store = ref_store;
 	strbuf_release(&sb);
+
 	return ref_iterator;
 }
 
+static enum iterator_selection reflog_iterator_select(
+	struct ref_iterator *iter_worktree,
+	struct ref_iterator *iter_common,
+	void *cb_data)
+{
+	if (iter_worktree) {
+		/*
+		 * We're a bit loose here. We probably should ignore
+		 * common refs if they are accidentally added as
+		 * per-worktree refs.
+		 */
+		return ITER_SELECT_0;
+	} else if (iter_common) {
+		if (ref_type(iter_common->refname) == REF_TYPE_NORMAL)
+			return ITER_SELECT_1;
+
+		/*
+		 * The main ref store may contain main worktree's
+		 * per-worktree refs, which should be ignored
+		 */
+		return ITER_SKIP_1;
+	} else
+		return ITER_DONE;
+}
+
+static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
+{
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ,
+			       "reflog_iterator_begin");
+
+	if (!strcmp(refs->gitdir, refs->gitcommondir)) {
+		return reflog_iterator_begin(ref_store, refs->gitcommondir);
+	} else {
+		return merge_ref_iterator_begin(
+			0,
+			reflog_iterator_begin(ref_store, refs->gitdir),
+			reflog_iterator_begin(ref_store, refs->gitcommondir),
+			reflog_iterator_select, refs);
+	}
+}
+
 /*
  * If update is a direct update of head_ref (the reference pointed to
  * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
@@ -2115,11 +2134,10 @@ static int split_head_update(struct ref_update *update,
 
 	/*
 	 * First make sure that HEAD is not already in the
-	 * transaction. This insertion is O(N) in the transaction
+	 * transaction. This check is O(lg N) in the transaction
 	 * size, but it happens at most once per transaction.
 	 */
-	item = string_list_insert(affected_refnames, "HEAD");
-	if (item->util) {
+	if (string_list_has_string(affected_refnames, "HEAD")) {
 		/* An entry already existed */
 		strbuf_addf(err,
 			    "multiple updates for 'HEAD' (including one "
@@ -2131,9 +2149,17 @@ static int split_head_update(struct ref_update *update,
 	new_update = ref_transaction_add_update(
 			transaction, "HEAD",
 			update->flags | REF_LOG_ONLY | REF_NODEREF,
-			update->new_oid.hash, update->old_oid.hash,
+			&update->new_oid, &update->old_oid,
 			update->msg);
 
+	/*
+	 * Add "HEAD". This insertion is O(N) in the transaction
+	 * size, but it happens at most once per transaction.
+	 * Add new_update->refname instead of a literal "HEAD".
+	 */
+	if (strcmp(new_update->refname, "HEAD"))
+		BUG("%s unexpectedly not 'HEAD'", new_update->refname);
+	item = string_list_insert(affected_refnames, new_update->refname);
 	item->util = new_update;
 
 	return 0;
@@ -2160,13 +2186,12 @@ static int split_symref_update(struct files_ref_store *refs,
 
 	/*
 	 * First make sure that referent is not already in the
-	 * transaction. This insertion is O(N) in the transaction
+	 * transaction. This check is O(lg N) in the transaction
 	 * size, but it happens at most once per symref in a
 	 * transaction.
 	 */
-	item = string_list_insert(affected_refnames, referent);
-	if (item->util) {
-		/* An entry already existed */
+	if (string_list_has_string(affected_refnames, referent)) {
+		/* An entry already exists */
 		strbuf_addf(err,
 			    "multiple updates for '%s' (including one "
 			    "via symref '%s') are not allowed",
@@ -2188,7 +2213,7 @@ static int split_symref_update(struct files_ref_store *refs,
 
 	new_update = ref_transaction_add_update(
 			transaction, referent, new_flags,
-			update->new_oid.hash, update->old_oid.hash,
+			&update->new_oid, &update->old_oid,
 			update->msg);
 
 	new_update->parent_update = update;
@@ -2201,6 +2226,17 @@ static int split_symref_update(struct files_ref_store *refs,
 	update->flags |= REF_LOG_ONLY | REF_NODEREF;
 	update->flags &= ~REF_HAVE_OLD;
 
+	/*
+	 * Add the referent. This insertion is O(N) in the transaction
+	 * size, but it happens at most once per symref in a
+	 * transaction. Make sure to add new_update->refname, which will
+	 * be valid as long as affected_refnames is in use, and NOT
+	 * referent, which might soon be freed by our caller.
+	 */
+	item = string_list_insert(affected_refnames, new_update->refname);
+	if (item->util)
+		BUG("%s unexpectedly found in affected_refnames",
+		    new_update->refname);
 	item->util = new_update;
 
 	return 0;
@@ -2272,7 +2308,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 	struct strbuf referent = STRBUF_INIT;
 	int mustexist = (update->flags & REF_HAVE_OLD) &&
 		!is_null_oid(&update->old_oid);
-	int ret;
+	int ret = 0;
 	struct ref_lock *lock;
 
 	files_assert_main_repository(refs, "lock_ref_for_update");
@@ -2284,7 +2320,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 		ret = split_head_update(update, transaction, head_ref,
 					affected_refnames, err);
 		if (ret)
-			return ret;
+			goto out;
 	}
 
 	ret = lock_raw_ref(refs, update->refname, mustexist,
@@ -2298,7 +2334,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 		strbuf_addf(err, "cannot lock ref '%s': %s",
 			    original_update_refname(update), reason);
 		free(reason);
-		return ret;
+		goto out;
 	}
 
 	update->backend_data = lock;
@@ -2312,15 +2348,17 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 			 */
 			if (refs_read_ref_full(&refs->base,
 					       referent.buf, 0,
-					       lock->old_oid.hash, NULL)) {
+					       &lock->old_oid, NULL)) {
 				if (update->flags & REF_HAVE_OLD) {
 					strbuf_addf(err, "cannot lock ref '%s': "
 						    "error reading reference",
 						    original_update_refname(update));
-					return -1;
+					ret = TRANSACTION_GENERIC_ERROR;
+					goto out;
 				}
 			} else if (check_old_oid(update, &lock->old_oid, err)) {
-				return TRANSACTION_GENERIC_ERROR;
+				ret = TRANSACTION_GENERIC_ERROR;
+				goto out;
 			}
 		} else {
 			/*
@@ -2334,13 +2372,15 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 						  referent.buf, transaction,
 						  affected_refnames, err);
 			if (ret)
-				return ret;
+				goto out;
 		}
 	} else {
 		struct ref_update *parent_update;
 
-		if (check_old_oid(update, &lock->old_oid, err))
-			return TRANSACTION_GENERIC_ERROR;
+		if (check_old_oid(update, &lock->old_oid, err)) {
+			ret = TRANSACTION_GENERIC_ERROR;
+			goto out;
+		}
 
 		/*
 		 * If this update is happening indirectly because of a
@@ -2377,7 +2417,8 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 				    "cannot update ref '%s': %s",
 				    update->refname, write_err);
 			free(write_err);
-			return TRANSACTION_GENERIC_ERROR;
+			ret = TRANSACTION_GENERIC_ERROR;
+			goto out;
 		} else {
 			update->flags |= REF_NEEDS_COMMIT;
 		}
@@ -2388,13 +2429,17 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 		 * the lockfile is still open. Close it to
 		 * free up the file descriptor:
 		 */
-		if (close_ref(lock)) {
+		if (close_ref_gently(lock)) {
 			strbuf_addf(err, "couldn't close '%s.lock'",
 				    update->refname);
-			return TRANSACTION_GENERIC_ERROR;
+			ret = TRANSACTION_GENERIC_ERROR;
+			goto out;
 		}
 	}
-	return 0;
+
+out:
+	strbuf_release(&referent);
+	return ret;
 }
 
 struct files_transaction_backend_data {
@@ -2450,7 +2495,6 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 	char *head_ref = NULL;
 	int head_type;
-	struct object_id head_oid;
 	struct files_transaction_backend_data *backend_data;
 	struct ref_transaction *packed_transaction = NULL;
 
@@ -2507,7 +2551,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 	 */
 	head_ref = refs_resolve_refdup(ref_store, "HEAD",
 				       RESOLVE_REF_NO_RECURSE,
-				       head_oid.hash, &head_type);
+				       NULL, &head_type);
 
 	if (head_ref && !(head_type & REF_ISSYMREF)) {
 		FREE_AND_NULL(head_ref);
@@ -2527,7 +2571,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 		ret = lock_ref_for_update(refs, update, transaction,
 					  head_ref, &affected_refnames, err);
 		if (ret)
-			break;
+			goto cleanup;
 
 		if (update->flags & REF_DELETING &&
 		    !(update->flags & REF_LOG_ONLY) &&
@@ -2551,7 +2595,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 			ref_transaction_add_update(
 					packed_transaction, update->refname,
 					update->flags & ~REF_HAVE_OLD,
-					update->new_oid.hash, update->old_oid.hash,
+					&update->new_oid, &update->old_oid,
 					NULL);
 		}
 	}
@@ -2820,7 +2864,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 		 */
 		ref_transaction_add_update(packed_transaction, update->refname,
 					   update->flags & ~REF_HAVE_OLD,
-					   update->new_oid.hash, update->old_oid.hash,
+					   &update->new_oid, &update->old_oid,
 					   NULL);
 	}
 
@@ -2881,7 +2925,7 @@ static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
 }
 
 static int files_reflog_expire(struct ref_store *ref_store,
-			       const char *refname, const unsigned char *sha1,
+			       const char *refname, const struct object_id *oid,
 			       unsigned int flags,
 			       reflog_expiry_prepare_fn prepare_fn,
 			       reflog_expiry_should_prune_fn should_prune_fn,
@@ -2898,7 +2942,6 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	int status = 0;
 	int type;
 	struct strbuf err = STRBUF_INIT;
-	struct object_id oid;
 
 	memset(&cb, 0, sizeof(cb));
 	cb.flags = flags;
@@ -2910,9 +2953,9 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	 * reference itself, plus we might need to update the
 	 * reference if --updateref was specified:
 	 */
-	lock = lock_ref_sha1_basic(refs, refname, sha1,
-				   NULL, NULL, REF_NODEREF,
-				   &type, &err);
+	lock = lock_ref_oid_basic(refs, refname, oid,
+				  NULL, NULL, REF_NODEREF,
+				  &type, &err);
 	if (!lock) {
 		error("cannot lock ref '%s': %s", refname, err.buf);
 		strbuf_release(&err);
@@ -2948,9 +2991,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		}
 	}
 
-	hashcpy(oid.hash, sha1);
-
-	(*prepare_fn)(refname, &oid, cb.policy_cb);
+	(*prepare_fn)(refname, oid, cb.policy_cb);
 	refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
 	(*cleanup_fn)(cb.policy_cb);
 
@@ -2966,16 +3007,17 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			!(type & REF_ISSYMREF) &&
 			!is_null_oid(&cb.last_kept_oid);
 
-		if (close_lock_file(&reflog_lock)) {
+		if (close_lock_file_gently(&reflog_lock)) {
 			status |= error("couldn't write %s: %s", log_file,
 					strerror(errno));
+			rollback_lock_file(&reflog_lock);
 		} else if (update &&
-			   (write_in_full(get_lock_file_fd(lock->lk),
-				oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
-			    write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
-			    close_ref(lock) < 0)) {
+			   (write_in_full(get_lock_file_fd(&lock->lk),
+				oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) < 0 ||
+			    write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
+			    close_ref_gently(lock) < 0)) {
 			status |= error("couldn't write %s",
-					get_lock_file_path(lock->lk));
+					get_lock_file_path(&lock->lk));
 			rollback_lock_file(&reflog_lock);
 		} else if (commit_lock_file(&reflog_lock)) {
 			status |= error("unable to write reflog '%s' (%s)",
@@ -3026,10 +3068,10 @@ struct ref_storage_be refs_be_files = {
 	files_initial_transaction_commit,
 
 	files_pack_refs,
-	files_peel_ref,
 	files_create_symref,
 	files_delete_refs,
 	files_rename_ref,
+	files_copy_ref,
 
 	files_ref_iterator_begin,
 	files_read_raw_ref,