Delete directories left empty after ref deletion

index f902393..be4ffdc 100644
@@ -2631,7 +2631,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
 			   sha1, NULL) &&
 	    delete_ref(newrefname, NULL, REF_NODEREF)) {
-		if (errno==EISDIR) {
+		if (errno == EISDIR) {
 			struct strbuf path = STRBUF_INIT;
 			int result;
 

index 708b260..dc81acc 100644
@@ -62,11 +62,12 @@
  * This function does not check that the reference name is legal; for
  * that, use check_refname_format().
  *
- * We consider a refname that starts with "refs/" to be safe as long
- * as any ".." components that it might contain do not escape "refs/".
- * Names that do not start with "refs/" are considered safe iff they
- * consist entirely of upper case characters and '_' (like "HEAD" and
- * "MERGE_HEAD" but not "config" or "FOO/BAR").
+ * A refname that starts with "refs/" is considered safe iff it
+ * doesn't contain any "." or ".." components or consecutive '/'
+ * characters, end with '/', or (on Windows) contain any '\'
+ * characters. Names that do not start with "refs/" are considered
+ * safe iff they consist entirely of upper case characters and '_'
+ * (like "HEAD" and "MERGE_HEAD" but not "config" or "FOO/BAR").
  */
 int refname_is_safe(const char *refname);
 

index 1173071..10395e7 100644
@@ -166,10 +166,14 @@ enum scld_error safe_create_leading_directories(char *path)
 
 enum scld_error safe_create_leading_directories_const(const char *path)
 {
+	int save_errno;
 	/* path points to cache entries, so xstrdup before messing with it */
 	char *buf = xstrdup(path);
 	enum scld_error result = safe_create_leading_directories(buf);
+
+	save_errno = errno;
 	free(buf);
+	errno = save_errno;
 	return result;
 }
 

index a50a61a..8177c3a 100644
@@ -1031,8 +1031,9 @@ int adjust_shared_perm(const char *path);
 
 /*
  * Create the directory containing the named path, using care to be
- * somewhat safe against races.  Return one of the scld_error values
- * to indicate success/failure.
+ * somewhat safe against races. Return one of the scld_error values to
+ * indicate success/failure. On error, set errno to describe the
+ * problem.
  *
  * SCLD_VANISHED indicates that one of the ancestor directories of the
  * path existed at one point during the function call and then

index 10395e7..ae8f0b4 100644
@@ -137,8 +137,10 @@ enum scld_error safe_create_leading_directories(char *path)
 		*slash = '\0';
 		if (!stat(path, &st)) {
 			/* path exists */
-			if (!S_ISDIR(st.st_mode))
+			if (!S_ISDIR(st.st_mode)) {
+				errno = ENOTDIR;
 				ret = SCLD_EXISTS;
+			}
 		} else if (mkdir(path, 0777)) {
 			if (errno == EEXIST &&
 			    !stat(path, &st) && S_ISDIR(st.st_mode))

index 8177c3a..95cde14 100644
@@ -1057,6 +1057,49 @@ enum scld_error {
 enum scld_error safe_create_leading_directories(char *path);
 enum scld_error safe_create_leading_directories_const(const char *path);
 
+/*
+ * Callback function for raceproof_create_file(). This function is
+ * expected to do something that makes dirname(path) permanent despite
+ * the fact that other processes might be cleaning up empty
+ * directories at the same time. Usually it will create a file named
+ * path, but alternatively it could create another file in that
+ * directory, or even chdir() into that directory. The function should
+ * return 0 if the action was completed successfully. On error, it
+ * should return a nonzero result and set errno.
+ * raceproof_create_file() treats two errno values specially:
+ *
+ * - ENOENT -- dirname(path) does not exist. In this case,
+ *             raceproof_create_file() tries creating dirname(path)
+ *             (and any parent directories, if necessary) and calls
+ *             the function again.
+ *
+ * - EISDIR -- the file already exists and is a directory. In this
+ *             case, raceproof_create_file() removes the directory if
+ *             it is empty (and recursively any empty directories that
+ *             it contains) and calls the function again.
+ *
+ * Any other errno causes raceproof_create_file() to fail with the
+ * callback's return value and errno.
+ *
+ * Obviously, this function should be OK with being called again if it
+ * fails with ENOENT or EISDIR. In other scenarios it will not be
+ * called again.
+ */
+typedef int create_file_fn(const char *path, void *cb);
+
+/*
+ * Create a file in dirname(path) by calling fn, creating leading
+ * directories if necessary. Retry a few times in case we are racing
+ * with another process that is trying to clean up the directory that
+ * contains path. See the documentation for create_file_fn for more
+ * details.
+ *
+ * Return the value and set the errno that resulted from the most
+ * recent call of fn. fn is always called at least once, and will be
+ * called more than once if it returns ENOENT or EISDIR.
+ */
+int raceproof_create_file(const char *path, create_file_fn fn, void *cb);
+
 int mkdir_in_gitdir(const char *path);
 extern char *expand_user_path(const char *path);
 const char *enter_repo(const char *path, int strict);

74 lines not on this page · raw message

index be4ffdc..7d4658a 100644
@@ -2000,7 +2000,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	struct strbuf ref_file = STRBUF_INIT;
 	struct ref_lock *lock;
 	int last_errno = 0;
-	int lflags = LOCK_NO_DEREF;
 	int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 	int resolve_flags = RESOLVE_REF_NO_RECURSE;
 	int attempts_remaining = 3;

@@ -2083,7 +2082,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 		goto error_return;
 	}
 
-	if (hold_lock_file_for_update(lock->lk, ref_file.buf, lflags) < 0) {
+	if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
 		last_errno = errno;
 		if (errno == ENOENT && --attempts_remaining > 0)
 			/*

index 7d4658a..74de289 100644
@@ -1985,6 +1985,13 @@ static int remove_empty_directories(struct strbuf *path)
 	return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
 }
 
+static int create_reflock(const char *path, void *cb)
+{
+	struct lock_file *lk = cb;
+
+	return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
+}
+
 /*
  * Locks a ref returning the lock on success and NULL on failure.
  * On failure errno is set to something meaningful.

@@ -2002,7 +2009,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	int last_errno = 0;
 	int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 	int resolve_flags = RESOLVE_REF_NO_RECURSE;
-	int attempts_remaining = 3;
 	int resolved;
 
 	assert_main_repository(&refs->base, "lock_ref_sha1_basic");

@@ -2067,35 +2073,12 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 
 	lock->ref_name = xstrdup(refname);
 
- retry:
-	switch (safe_create_leading_directories_const(ref_file.buf)) {
-	case SCLD_OK:
-		break; /* success */
-	case SCLD_VANISHED:
-		if (--attempts_remaining > 0)
-			goto retry;
-		/* fall through */
-	default:
+	if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
 		last_errno = errno;
-		strbuf_addf(err, "unable to create directory for '%s'",
-			    ref_file.buf);
+		unable_to_lock_message(ref_file.buf, errno, err);
 		goto error_return;
 	}
 
-	if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
-		last_errno = errno;
-		if (errno == ENOENT && --attempts_remaining > 0)
-			/*
-			 * Maybe somebody just deleted one of the
-			 * directories leading to ref_file.  Try
-			 * again:
-			 */
-			goto retry;
-		else {
-			unable_to_lock_message(ref_file.buf, errno, err);
-			goto error_return;
-		}
-	}
 	if (verify_lock(lock, old_sha1, mustexist, err)) {
 		last_errno = errno;
 		goto error_return;

index 74de289..3f18a01 100644
@@ -2489,55 +2489,42 @@ static int files_delete_refs(struct ref_store *ref_store,
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log_callback(const char *path, void *cb)
 {
-	int attempts_remaining = 4;
-	struct strbuf path = STRBUF_INIT;
-	int ret = -1;
+	int *true_errno = cb;
 
- retry:
-	strbuf_reset(&path);
-	strbuf_git_path(&path, "logs/%s", newrefname);
-	switch (safe_create_leading_directories_const(path.buf)) {
-	case SCLD_OK:
-		break; /* success */
-	case SCLD_VANISHED:
-		if (--attempts_remaining > 0)
-			goto retry;
-		/* fall through */
-	default:
-		error("unable to create directory for %s", newrefname);
-		goto out;
+	if (rename(git_path(TMP_RENAMED_LOG), path)) {
+		/*
+		 * rename(a, b) when b is an existing directory ought
+		 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
+		 * Sheesh. Record the true errno for error reporting,
+		 * but report EISDIR to raceproof_create_file() so
+		 * that it knows to retry.
+		 */
+		*true_errno = errno;
+		if (errno == ENOTDIR)
+			errno = EISDIR;
+		return -1;
+	} else {
+		return 0;
 	}
+}
 
-	if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
-		if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
-			/*
-			 * rename(a, b) when b is an existing
-			 * directory ought to result in ISDIR, but
-			 * Solaris 5.8 gives ENOTDIR.  Sheesh.
-			 */
-			if (remove_empty_directories(&path)) {
-				error("Directory not empty: logs/%s", newrefname);
-				goto out;
-			}
-			goto retry;
-		} else if (errno == ENOENT && --attempts_remaining > 0) {
-			/*
-			 * Maybe another process just deleted one of
-			 * the directories in the path to newrefname.
-			 * Try again from the beginning.
-			 */
-			goto retry;
-		} else {
+static int rename_tmp_log(const char *newrefname)
+{
+	char *path = git_pathdup("logs/%s", newrefname);
+	int ret, true_errno;
+
+	ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
+	if (ret) {
+		if (errno == EISDIR)
+			error("Directory not empty: %s", path);
+		else
 			error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
-				newrefname, strerror(errno));
-			goto out;
-		}
+				newrefname, strerror(true_errno));
 	}
-	ret = 0;
-out:
-	strbuf_release(&path);
+
+	free(path);
 	return ret;
 }
 

index 3f18a01..49a119c 100644
@@ -2518,10 +2518,11 @@ static int rename_tmp_log(const char *newrefname)
 	ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
 	if (ret) {
 		if (errno == EISDIR)
-			error("Directory not empty: %s", path);
+			error("directory not empty: %s", path);
 		else
-			error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
-				newrefname, strerror(true_errno));
+			error("unable to move logfile %s to %s: %s",
+			      git_path(TMP_RENAMED_LOG), path,
+			      strerror(true_errno));
 	}
 
 	free(path);

index 49a119c..fd8a751 100644
@@ -2832,14 +2832,6 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write(const char *refname, const unsigned char *old_sha1,
-			 const unsigned char *new_sha1, const char *msg,
-			 int flags, struct strbuf *err)
-{
-	return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
-				   err);
-}
-
 int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)

@@ -2903,7 +2895,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 	assert_main_repository(&refs->base, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
+	if (files_log_ref_write(lock->ref_name, lock->old_oid.hash, sha1,
+				logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
 			    lock->ref_name, old_msg);

@@ -2934,7 +2927,7 @@ static int commit_ref_update(struct files_ref_store *refs,
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
+			if (files_log_ref_write("HEAD", lock->old_oid.hash, sha1,
 					  logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);

@@ -2973,7 +2966,8 @@ static void update_symref_reflog(struct ref_lock *lock, const char *refname,
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
 	if (logmsg && !read_ref(target, new_sha1) &&
-	    log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
+	    files_log_ref_write(refname, lock->old_oid.hash, new_sha1,
+				logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}

@@ -3748,9 +3742,11 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (log_ref_write(lock->ref_name, lock->old_oid.hash,
-					  update->new_sha1,
-					  update->msg, update->flags, err)) {
+			if (files_log_ref_write(lock->ref_name,
+						lock->old_oid.hash,
+						update->new_sha1,
+						update->msg, update->flags,
+						err)) {
 				char *old_msg = strbuf_detach(err, NULL);
 
 				strbuf_addf(err, "cannot update the ref '%s': %s",

index fd8a751..c8f6d82 100644
@@ -2718,45 +2718,64 @@ static int commit_ref(struct ref_lock *lock)
  */
 static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
 {
-	int logfd, oflags = O_APPEND | O_WRONLY;
+	int logfd;
 
 	strbuf_git_path(logfile, "logs/%s", refname);
+
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (safe_create_leading_directories(logfile->buf) < 0) {
 			strbuf_addf(err, "unable to create directory for '%s': "
 				    "%s", logfile->buf, strerror(errno));
 			return -1;
 		}
-		oflags |= O_CREAT;
-	}
-
-	logfd = open(logfile->buf, oflags, 0666);
-	if (logfd < 0) {
-		if (!(oflags & O_CREAT) && (errno == ENOENT || errno == EISDIR))
-			return 0;
+		logfd = open(logfile->buf, O_APPEND | O_WRONLY | O_CREAT, 0666);
+		if (logfd < 0) {
+			if (errno == EISDIR) {
+				/*
+				 * The directory that is in the way might be
+				 * empty. Try to remove it.
+				 */
+				if (remove_empty_directories(logfile)) {
+					strbuf_addf(err, "there are still logs under "
+						    "'%s'", logfile->buf);
+					return -1;
+				}
+				logfd = open(logfile->buf, O_APPEND | O_WRONLY | O_CREAT, 0666);
+			}
 
-		if (errno == EISDIR) {
-			if (remove_empty_directories(logfile)) {
-				strbuf_addf(err, "there are still logs under "
-					    "'%s'", logfile->buf);
+			if (logfd < 0) {
+				strbuf_addf(err, "unable to append to '%s': %s",
+					    logfile->buf, strerror(errno));
 				return -1;
 			}
-			logfd = open(logfile->buf, oflags, 0666);
 		}
-
+	} else {
+		logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);
 		if (logfd < 0) {
-			strbuf_addf(err, "unable to append to '%s': %s",
-				    logfile->buf, strerror(errno));
-			return -1;
+			if (errno == ENOENT || errno == EISDIR) {
+				/*
+				 * The logfile doesn't already exist,
+				 * but that is not an error; it only
+				 * means that we won't write log
+				 * entries to it.
+				 */
+				;
+			} else {
+				strbuf_addf(err, "unable to append to '%s': %s",
+					    logfile->buf, strerror(errno));
+				return -1;
+			}
 		}
 	}
 
-	adjust_shared_perm(logfile->buf);
-	close(logfd);
+	if (logfd >= 0) {
+		adjust_shared_perm(logfile->buf);
+		close(logfd);
+	}
+
 	return 0;
 }
 
-
 static int files_create_reflog(struct ref_store *ref_store,
 			       const char *refname, int force_create,
 			       struct strbuf *err)

index c8f6d82..27d4fd3 100644
@@ -2710,6 +2710,14 @@ static int commit_ref(struct ref_lock *lock)
 	return 0;
 }
 
+static int open_or_create_logfile(const char *path, void *cb)
+{
+	int *fd = cb;
+
+	*fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
+	return (*fd < 0) ? -1 : 0;
+}
+
 /*
  * Create a reflog for a ref.  If force_create = 0, the reflog will
  * only be created for certain refs (those for which

@@ -2723,31 +2731,18 @@ static int log_ref_setup(const char *refname, struct strbuf *logfile, struct str
 	strbuf_git_path(logfile, "logs/%s", refname);
 
 	if (force_create || should_autocreate_reflog(refname)) {
-		if (safe_create_leading_directories(logfile->buf) < 0) {
-			strbuf_addf(err, "unable to create directory for '%s': "
-				    "%s", logfile->buf, strerror(errno));
-			return -1;
-		}
-		logfd = open(logfile->buf, O_APPEND | O_WRONLY | O_CREAT, 0666);
-		if (logfd < 0) {
-			if (errno == EISDIR) {
-				/*
-				 * The directory that is in the way might be
-				 * empty. Try to remove it.
-				 */
-				if (remove_empty_directories(logfile)) {
-					strbuf_addf(err, "there are still logs under "
-						    "'%s'", logfile->buf);
-					return -1;
-				}
-				logfd = open(logfile->buf, O_APPEND | O_WRONLY | O_CREAT, 0666);
-			}
-
-			if (logfd < 0) {
+		if (raceproof_create_file(logfile->buf, open_or_create_logfile, &logfd)) {
+			if (errno == ENOENT)
+				strbuf_addf(err, "unable to create directory for '%s': "
+					    "%s", logfile->buf, strerror(errno));
+			else if (errno == EISDIR)
+				strbuf_addf(err, "there are still logs under '%s'",
+					    logfile->buf);
+			else
 				strbuf_addf(err, "unable to append to '%s': %s",
 					    logfile->buf, strerror(errno));
-				return -1;
-			}
+
+			return -1;
 		}
 	} else {
 		logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);

index 27d4fd3..f723834 100644
@@ -2719,19 +2719,23 @@ static int open_or_create_logfile(const char *path, void *cb)
 }
 
 /*
- * Create a reflog for a ref.  If force_create = 0, the reflog will
- * only be created for certain refs (those for which
- * should_autocreate_reflog returns non-zero.  Otherwise, create it
- * regardless of the ref name.  Fill in *err and return -1 on failure.
+ * Create a reflog for a ref. Store its path to *logfile. If
+ * force_create = 0, only create the reflog for certain refs (those
+ * for which should_autocreate_reflog returns non-zero). Otherwise,
+ * create it regardless of the reference name. If the logfile already
+ * existed or was created, return 0 and set *logfd to the file
+ * descriptor opened for appending to the file. If no logfile exists
+ * and we decided not to create one, return 0 and set *logfd to -1. On
+ * failure, fill in *err, set *logfd to -1, and return -1.
  */
-static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
+static int log_ref_setup(const char *refname,
+			 struct strbuf *logfile, int *logfd,
+			 struct strbuf *err, int force_create)
 {
-	int logfd;
-
 	strbuf_git_path(logfile, "logs/%s", refname);
 
 	if (force_create || should_autocreate_reflog(refname)) {
-		if (raceproof_create_file(logfile->buf, open_or_create_logfile, &logfd)) {
+		if (raceproof_create_file(logfile->buf, open_or_create_logfile, logfd)) {
 			if (errno == ENOENT)
 				strbuf_addf(err, "unable to create directory for '%s': "
 					    "%s", logfile->buf, strerror(errno));

@@ -2745,8 +2749,8 @@ static int log_ref_setup(const char *refname, struct strbuf *logfile, struct str
 			return -1;
 		}
 	} else {
-		logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);
-		if (logfd < 0) {
+		*logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);
+		if (*logfd < 0) {
 			if (errno == ENOENT || errno == EISDIR) {
 				/*
 				 * The logfile doesn't already exist,

@@ -2763,10 +2767,8 @@ static int log_ref_setup(const char *refname, struct strbuf *logfile, struct str
 		}
 	}
 
-	if (logfd >= 0) {
+	if (*logfd >= 0)
 		adjust_shared_perm(logfile->buf);
-		close(logfd);
-	}
 
 	return 0;
 }

@@ -2777,11 +2779,14 @@ static int files_create_reflog(struct ref_store *ref_store,
 {
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
+	int fd;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "create_reflog");
 
-	ret = log_ref_setup(refname, &sb, err, force_create);
+	ret = log_ref_setup(refname, &sb, &fd, err, force_create);
+	if (fd >= 0)
+		close(fd);
 	strbuf_release(&sb);
 	return ret;
 }

@@ -2817,17 +2822,17 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 			   struct strbuf *logfile, int flags,
 			   struct strbuf *err)
 {
-	int logfd, result, oflags = O_APPEND | O_WRONLY;
+	int logfd, result;
 
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
+	result = log_ref_setup(refname, logfile, &logfd, err,
+			       flags & REF_FORCE_CREATE_REFLOG);
 
 	if (result)
 		return result;
 
-	logfd = open(logfile->buf, oflags);
 	if (logfd < 0)
 		return 0;
 	result = log_ref_write_fd(logfd, old_sha1, new_sha1,

index f723834..9c5e804 100644
@@ -2838,14 +2838,18 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
 				  git_committer_info(0), msg);
 	if (result) {
-		strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
-			    strerror(errno));
+		int save_errno = errno;
+
+		strbuf_addf(err, "unable to append to '%s': %s",
+			    git_path("logs/%s", refname), strerror(save_errno));
 		close(logfd);
 		return -1;
 	}
 	if (close(logfd)) {
-		strbuf_addf(err, "unable to append to '%s': %s", logfile->buf,
-			    strerror(errno));
+		int save_errno = errno;
+
+		strbuf_addf(err, "unable to append to '%s': %s",
+			    git_path("logs/%s", refname), strerror(save_errno));
 		return -1;
 	}
 	return 0;

index 9c5e804..846380f 100644
@@ -2719,37 +2719,36 @@ static int open_or_create_logfile(const char *path, void *cb)
 }
 
 /*
- * Create a reflog for a ref. Store its path to *logfile. If
- * force_create = 0, only create the reflog for certain refs (those
- * for which should_autocreate_reflog returns non-zero). Otherwise,
- * create it regardless of the reference name. If the logfile already
- * existed or was created, return 0 and set *logfd to the file
- * descriptor opened for appending to the file. If no logfile exists
- * and we decided not to create one, return 0 and set *logfd to -1. On
- * failure, fill in *err, set *logfd to -1, and return -1.
+ * Create a reflog for a ref. If force_create = 0, only create the
+ * reflog for certain refs (those for which should_autocreate_reflog
+ * returns non-zero). Otherwise, create it regardless of the reference
+ * name. If the logfile already existed or was created, return 0 and
+ * set *logfd to the file descriptor opened for appending to the file.
+ * If no logfile exists and we decided not to create one, return 0 and
+ * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
+ * return -1.
  */
-static int log_ref_setup(const char *refname,
-			 struct strbuf *logfile, int *logfd,
-			 struct strbuf *err, int force_create)
+static int log_ref_setup(const char *refname, int force_create,
+			 int *logfd, struct strbuf *err)
 {
-	strbuf_git_path(logfile, "logs/%s", refname);
+	char *logfile = git_pathdup("logs/%s", refname);
 
 	if (force_create || should_autocreate_reflog(refname)) {
-		if (raceproof_create_file(logfile->buf, open_or_create_logfile, logfd)) {
+		if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
 			if (errno == ENOENT)
 				strbuf_addf(err, "unable to create directory for '%s': "
-					    "%s", logfile->buf, strerror(errno));
+					    "%s", logfile, strerror(errno));
 			else if (errno == EISDIR)
 				strbuf_addf(err, "there are still logs under '%s'",
-					    logfile->buf);
+					    logfile);
 			else
 				strbuf_addf(err, "unable to append to '%s': %s",
-					    logfile->buf, strerror(errno));
+					    logfile, strerror(errno));
 
-			return -1;
+			goto error;
 		}
 	} else {
-		*logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);
+		*logfd = open(logfile, O_APPEND | O_WRONLY, 0666);
 		if (*logfd < 0) {
 			if (errno == ENOENT || errno == EISDIR) {
 				/*

@@ -2761,34 +2760,39 @@ static int log_ref_setup(const char *refname,
 				;
 			} else {
 				strbuf_addf(err, "unable to append to '%s': %s",
-					    logfile->buf, strerror(errno));
-				return -1;
+					    logfile, strerror(errno));
+				goto error;
 			}
 		}
 	}
 
 	if (*logfd >= 0)
-		adjust_shared_perm(logfile->buf);
+		adjust_shared_perm(logfile);
 
+	free(logfile);
 	return 0;
+
+error:
+	free(logfile);
+	return -1;
 }
 
 static int files_create_reflog(struct ref_store *ref_store,
 			       const char *refname, int force_create,
 			       struct strbuf *err)
 {
-	int ret;
-	struct strbuf sb = STRBUF_INIT;
 	int fd;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "create_reflog");
 
-	ret = log_ref_setup(refname, &sb, &fd, err, force_create);
+	if (log_ref_setup(refname, force_create, &fd, err))
+		return -1;
+
 	if (fd >= 0)
 		close(fd);
-	strbuf_release(&sb);
-	return ret;
+
+	return 0;
 }
 
 static int log_ref_write_fd(int fd, const unsigned char *old_sha1,

@@ -2819,16 +2823,15 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 
 static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 			   const unsigned char *new_sha1, const char *msg,
-			   struct strbuf *logfile, int flags,
-			   struct strbuf *err)
+			   int flags, struct strbuf *err)
 {
 	int logfd, result;
 
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	result = log_ref_setup(refname, logfile, &logfd, err,
-			       flags & REF_FORCE_CREATE_REFLOG);
+	result = log_ref_setup(refname, flags & REF_FORCE_CREATE_REFLOG,
+			       &logfd, err);
 
 	if (result)
 		return result;

@@ -2859,11 +2862,7 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)
 {
-	struct strbuf sb = STRBUF_INIT;
-	int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
-				  err);
-	strbuf_release(&sb);
-	return ret;
+	return log_ref_write_1(refname, old_sha1, new_sha1, msg, flags, err);
 }
 
 /*

index 846380f..39d6f5b 100644
@@ -2821,9 +2821,9 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
-			   const unsigned char *new_sha1, const char *msg,
-			   int flags, struct strbuf *err)
+int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+			const unsigned char *new_sha1, const char *msg,
+			int flags, struct strbuf *err)
 {
 	int logfd, result;
 

@@ -2858,13 +2858,6 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	return 0;
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err)
-{
-	return log_ref_write_1(refname, old_sha1, new_sha1, msg, flags, err);
-}
-
 /*
  * Write sha1 into the open lockfile, then close the lockfile. On
  * errors, rollback the lockfile, fill in *err and

index 39d6f5b..4d55364 100644
@@ -2430,10 +2430,7 @@ static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
 		 * loose.  The loose file name is the same as the
 		 * lockfile name, minus ".lock":
 		 */
-		char *loose_filename = get_locked_file_path(lock->lk);
-		int res = unlink_or_msg(loose_filename, err);
-		free(loose_filename);
-		if (res)
+		if (unlink_or_msg(git_path("%s", lock->ref_name), err))
 			return 1;
 	}
 	return 0;

index 4d55364..9abd7c3 100644
@@ -2421,21 +2421,6 @@ static int repack_without_refs(struct files_ref_store *refs,
 	return ret;
 }
 
-static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
-{
-	assert(err);
-
-	if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
-		/*
-		 * loose.  The loose file name is the same as the
-		 * lockfile name, minus ".lock":
-		 */
-		if (unlink_or_msg(git_path("%s", lock->ref_name), err))
-			return 1;
-	}
-	return 0;
-}
-
 static int files_delete_refs(struct ref_store *ref_store,
 			     struct string_list *refnames, unsigned int flags)
 {

@@ -3788,9 +3773,13 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_DELETING &&
 		    !(update->flags & REF_LOG_ONLY)) {
-			if (delete_ref_loose(lock, update->type, err)) {
-				ret = TRANSACTION_GENERIC_ERROR;
-				goto cleanup;
+			if (!(update->type & REF_ISPACKED) ||
+			    update->type & REF_ISSYMREF) {
+				/* It is a loose reference. */
+				if (unlink_or_msg(git_path("%s", lock->ref_name), err)) {
+					ret = TRANSACTION_GENERIC_ERROR;
+					goto cleanup;
+				}
 			}
 
 			if (!(update->flags & REF_ISPRUNING))

index 9abd7c3..92a9d99 100644
@@ -2282,13 +2282,13 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
 
 /*
  * Remove empty parents, but spare refs/ and immediate subdirs.
- * Note: munges *name.
+ * Note: munges *refname.
  */
-static void try_remove_empty_parents(char *name)
+static void try_remove_empty_parents(char *refname)
 {
 	char *p, *q;
 	int i;
-	p = name;
+	p = refname;
 	for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
 		while (*p && *p != '/')
 			p++;

@@ -2306,7 +2306,7 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		if (rmdir(git_path("%s", name)))
+		if (rmdir(git_path("%s", refname)))
 			break;
 	}
 }

index 92a9d99..88f8c7a 100644
@@ -2282,13 +2282,15 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
 
 /*
  * Remove empty parents, but spare refs/ and immediate subdirs.
- * Note: munges *refname.
  */
-static void try_remove_empty_parents(char *refname)
+static void try_remove_empty_parents(const char *refname)
 {
+	struct strbuf buf = STRBUF_INIT;
 	char *p, *q;
 	int i;
-	p = refname;
+
+	strbuf_addstr(&buf, refname);
+	p = buf.buf;
 	for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
 		while (*p && *p != '/')
 			p++;

@@ -2296,8 +2298,7 @@ static void try_remove_empty_parents(char *refname)
 		while (*p == '/')
 			p++;
 	}
-	for (q = p; *q; q++)
-		;
+	q = buf.buf + buf.len;
 	while (1) {
 		while (q > p && *q != '/')
 			q--;

@@ -2305,10 +2306,11 @@ static void try_remove_empty_parents(char *refname)
 			q--;
 		if (q == p)
 			break;
-		*q = '\0';
-		if (rmdir(git_path("%s", refname)))
+		strbuf_setlen(&buf, q - buf.buf);
+		if (rmdir(git_path("%s", buf.buf)))
 			break;
 	}
+	strbuf_release(&buf);
 }
 
 /* make sure nobody touched the ref, and unlink */

index 88f8c7a..bce0022 100644
@@ -2280,10 +2280,18 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
 	return 0;
 }
 
+enum {
+	REMOVE_EMPTY_PARENTS_REF = 0x01,
+	REMOVE_EMPTY_PARENTS_REFLOG = 0x02
+};
+
 /*
- * Remove empty parents, but spare refs/ and immediate subdirs.
+ * Remove empty parent directories associated with the specified
+ * reference and/or its reflog, but spare [logs/]refs/ and immediate
+ * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
+ * REMOVE_EMPTY_PARENTS_REFLOG.
  */
-static void try_remove_empty_parents(const char *refname)
+static void try_remove_empty_parents(const char *refname, unsigned int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
 	char *p, *q;

@@ -2299,7 +2307,7 @@ static void try_remove_empty_parents(const char *refname)
 			p++;
 	}
 	q = buf.buf + buf.len;
-	while (1) {
+	while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
 		while (q > p && *q != '/')
 			q--;
 		while (q > p && *(q-1) == '/')

@@ -2307,8 +2315,12 @@ static void try_remove_empty_parents(const char *refname)
 		if (q == p)
 			break;
 		strbuf_setlen(&buf, q - buf.buf);
-		if (rmdir(git_path("%s", buf.buf)))
-			break;
+		if ((flags & REMOVE_EMPTY_PARENTS_REF) &&
+		    rmdir(git_path("%s", buf.buf)))
+			flags &= ~REMOVE_EMPTY_PARENTS_REF;
+		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) &&
+		    rmdir(git_path("logs/%s", buf.buf)))
+			flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
 	}
 	strbuf_release(&buf);
 }

@@ -2334,7 +2346,7 @@ static void prune_ref(struct ref_to_prune *r)
 	}
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
-	try_remove_empty_parents(r->name);
+	try_remove_empty_parents(r->name, REMOVE_EMPTY_PARENTS_REF);
 }
 
 static void prune_refs(struct ref_to_prune *r)

index bce0022..c426575 100644
@@ -2346,7 +2346,6 @@ static void prune_ref(struct ref_to_prune *r)
 	}
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
-	try_remove_empty_parents(r->name, REMOVE_EMPTY_PARENTS_REF);
 }
 
 static void prune_refs(struct ref_to_prune *r)

@@ -3794,6 +3793,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto cleanup;
 				}
+				update->flags |= REF_DELETED_LOOSE;
 			}
 
 			if (!(update->flags & REF_ISPRUNING))

@@ -3806,16 +3806,38 @@ static int files_transaction_commit(struct ref_store *ref_store,
 		ret = TRANSACTION_GENERIC_ERROR;
 		goto cleanup;
 	}
-	for_each_string_list_item(ref_to_delete, &refs_to_delete)
-		unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
+
+	/* Delete the reflogs of any references that were deleted: */
+	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
+		if (!unlink_or_warn(git_path("logs/%s", ref_to_delete->string)))
+			try_remove_empty_parents(ref_to_delete->string,
+						 REMOVE_EMPTY_PARENTS_REFLOG);
+	}
+
 	clear_loose_ref_cache(refs);
 
 cleanup:
 	transaction->state = REF_TRANSACTION_CLOSED;
 
-	for (i = 0; i < transaction->nr; i++)
-		if (transaction->updates[i]->backend_data)
-			unlock_ref(transaction->updates[i]->backend_data);
+	for (i = 0; i < transaction->nr; i++) {
+		struct ref_update *update = transaction->updates[i];
+		struct ref_lock *lock = update->backend_data;
+
+		if (lock)
+			unlock_ref(lock);
+
+		if (update->flags & REF_DELETED_LOOSE) {
+			/*
+			 * The loose reference was deleted. Delete any
+			 * empty parent directories. (Note that this
+			 * can only work because we have already
+			 * removed the lockfile.)
+			 */
+			try_remove_empty_parents(update->refname,
+						 REMOVE_EMPTY_PARENTS_REF);
+		}
+	}
+
 	string_list_clear(&refs_to_delete, 0);
 	free(head_ref);
 	string_list_clear(&affected_refnames, 0);

index dc81acc..15d5a1e 100644
@@ -56,6 +56,12 @@
 #define REF_UPDATE_VIA_HEAD 0x100
 
 /*
+ * Used as a flag in ref_update::flags when the loose reference has
+ * been deleted.
+ */
+#define REF_DELETED_LOOSE 0x200
+
+/*
  * Return true iff refname is minimally safe. "Safe" here means that
  * deleting a loose reference by this name will not do any damage, for
  * example by causing a file that is not a reference to be deleted.

@@ -158,8 +164,9 @@ struct ref_update {
 
 	/*
 	 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
-	 * REF_DELETING, REF_ISPRUNING, REF_LOG_ONLY, and
-	 * REF_UPDATE_VIA_HEAD:
+	 * REF_DELETING, REF_ISPRUNING, REF_LOG_ONLY,
+	 * REF_UPDATE_VIA_HEAD, REF_NEEDS_COMMIT, and
+	 * REF_DELETED_LOOSE:
 	 */
 	unsigned int flags;