diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 259dce4994..9a914d0159 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -18,7 +18,7 @@ SYNOPSIS
 		   [--start-number <n>] [--numbered-files]
 		   [--in-reply-to=Message-Id] [--suffix=.<sfx>]
 		   [--ignore-if-in-upstream]
-		   [--subject-prefix=Subject-Prefix]
+		   [--subject-prefix=Subject-Prefix] [(--reroll-count|-v) <n>]
 		   [--to=<email>] [--cc=<email>]
 		   [--cover-letter] [--quiet] [--notes[=<ref>]]
 		   [<common diff options>]
@@ -166,6 +166,15 @@ will want to ensure that threading is disabled for `git send-email`.
 	allows for useful naming of a patch series, and can be
 	combined with the `--numbered` option.
 
+-v <n>::
+--reroll-count=<n>::
+	Mark the series as the <n>-th iteration of the topic. The
+	output filenames have `v<n>` pretended to them, and the
+	subject prefix ("PATCH" by default, but configurable via the
+	`--subject-prefix` option) has ` v<n>` appended to it.  E.g.
+	`--reroll-count=4` may produce `v4-0001-add-makefile.patch`
+	file that has "Subject: [PATCH v4 1/20] Add makefile" in it.
+
 --to=<email>::
 	Add a `To:` header to the email headers. This is in addition
 	to any configured headers, and may be used multiple times.
diff --git a/builtin/log.c b/builtin/log.c
index 3899b1d43a..5a4055eb0b 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -678,7 +678,7 @@ static int reopen_stdout(struct commit *commit, const char *subject,
 			 struct rev_info *rev, int quiet)
 {
 	struct strbuf filename = STRBUF_INIT;
-	int suffix_len = strlen(fmt_patch_suffix) + 1;
+	int suffix_len = strlen(rev->patch_suffix) + 1;
 
 	if (output_directory) {
 		strbuf_addstr(&filename, output_directory);
@@ -689,7 +689,12 @@ static int reopen_stdout(struct commit *commit, const char *subject,
 			strbuf_addch(&filename, '/');
 	}
 
-	get_patch_filename(commit, subject, rev->nr, fmt_patch_suffix, &filename);
+	if (rev->numbered_files)
+		strbuf_addf(&filename, "%d", rev->nr);
+	else if (commit)
+		fmt_output_commit(&filename, commit, rev);
+	else
+		fmt_output_subject(&filename, subject, rev);
 
 	if (!quiet)
 		fprintf(realstdout, "%s\n", filename.buf + outdir_offset);
@@ -773,7 +778,6 @@ static void add_branch_description(struct strbuf *buf, const char *branch_name)
 }
 
 static void make_cover_letter(struct rev_info *rev, int use_stdout,
-			      int numbered, int numbered_files,
 			      struct commit *origin,
 			      int nr, struct commit **list, struct commit *head,
 			      const char *branch_name,
@@ -796,7 +800,7 @@ static void make_cover_letter(struct rev_info *rev, int use_stdout,
 	committer = git_committer_info(0);
 
 	if (!use_stdout &&
-	    reopen_stdout(NULL, numbered_files ? NULL : "cover-letter", rev, quiet))
+	    reopen_stdout(NULL, rev->numbered_files ? NULL : "cover-letter", rev, quiet))
 		return;
 
 	log_write_email_headers(rev, head, &pp.subject, &pp.after_subject,
@@ -1060,7 +1064,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	int nr = 0, total, i;
 	int use_stdout = 0;
 	int start_number = -1;
-	int numbered_files = 0;		/* _just_ numbers */
+	int just_numbers = 0;
 	int ignore_if_in_upstream = 0;
 	int cover_letter = 0;
 	int boundary_count = 0;
@@ -1072,6 +1076,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	struct strbuf buf = STRBUF_INIT;
 	int use_patch_format = 0;
 	int quiet = 0;
+	int reroll_count = -1;
 	char *branch_name = NULL;
 	const struct option builtin_format_patch_options[] = {
 		{ OPTION_CALLBACK, 'n', "numbered", &numbered, NULL,
@@ -1085,12 +1090,14 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 			    N_("print patches to standard out")),
 		OPT_BOOLEAN(0, "cover-letter", &cover_letter,
 			    N_("generate a cover letter")),
-		OPT_BOOLEAN(0, "numbered-files", &numbered_files,
+		OPT_BOOLEAN(0, "numbered-files", &just_numbers,
 			    N_("use simple number sequence for output file names")),
 		OPT_STRING(0, "suffix", &fmt_patch_suffix, N_("sfx"),
 			    N_("use <sfx> instead of '.patch'")),
 		OPT_INTEGER(0, "start-number", &start_number,
 			    N_("start numbering patches at <n> instead of 1")),
+		OPT_INTEGER('v', "reroll-count", &reroll_count,
+			    N_("mark the series as Nth re-roll")),
 		{ OPTION_CALLBACK, 0, "subject-prefix", &rev, N_("prefix"),
 			    N_("Use [<prefix>] instead of [PATCH]"),
 			    PARSE_OPT_NONEG, subject_prefix_callback },
@@ -1164,6 +1171,14 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN |
 			     PARSE_OPT_KEEP_DASHDASH);
 
+	if (0 < reroll_count) {
+		struct strbuf sprefix = STRBUF_INIT;
+		strbuf_addf(&sprefix, "%s v%d",
+			    rev.subject_prefix, reroll_count);
+		rev.reroll_count = reroll_count;
+		rev.subject_prefix = strbuf_detach(&sprefix, NULL);
+	}
+
 	if (do_signoff) {
 		const char *committer;
 		const char *endpos;
@@ -1354,12 +1369,12 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		const char *msgid = clean_message_id(in_reply_to);
 		string_list_append(rev.ref_message_ids, msgid);
 	}
-	rev.numbered_files = numbered_files;
+	rev.numbered_files = just_numbers;
 	rev.patch_suffix = fmt_patch_suffix;
 	if (cover_letter) {
 		if (thread)
 			gen_message_id(&rev, "cover");
-		make_cover_letter(&rev, use_stdout, numbered, numbered_files,
+		make_cover_letter(&rev, use_stdout,
 				  origin, nr, list, head, branch_name, quiet);
 		total++;
 		start_number--;
@@ -1406,7 +1421,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		}
 
 		if (!use_stdout &&
-		    reopen_stdout(numbered_files ? NULL : commit, NULL, &rev, quiet))
+		    reopen_stdout(rev.numbered_files ? NULL : commit, NULL, &rev, quiet))
 			die(_("Failed to create output files"));
 		shown = log_tree_commit(&rev, commit);
 		free(commit->buffer);
diff --git a/log-tree.c b/log-tree.c
index 8876c736d4..f8487f8a8a 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -299,26 +299,34 @@ static unsigned int digits_in_number(unsigned int number)
 	return result;
 }
 
-void get_patch_filename(struct commit *commit, const char *subject, int nr,
-			const char *suffix, struct strbuf *buf)
+void fmt_output_subject(struct strbuf *filename,
+			const char *subject,
+			struct rev_info *info)
 {
-	int suffix_len = strlen(suffix) + 1;
-	int start_len = buf->len;
+	const char *suffix = info->patch_suffix;
+	int nr = info->nr;
+	int start_len = filename->len;
+	int max_len = start_len + FORMAT_PATCH_NAME_MAX - (strlen(suffix) + 1);
 
-	strbuf_addf(buf, commit || subject ? "%04d-" : "%d", nr);
-	if (commit || subject) {
-		int max_len = start_len + FORMAT_PATCH_NAME_MAX - suffix_len;
-		struct pretty_print_context ctx = {0};
+	if (0 < info->reroll_count)
+		strbuf_addf(filename, "v%d-", info->reroll_count);
+	strbuf_addf(filename, "%04d-%s", nr, subject);
 
-		if (subject)
-			strbuf_addstr(buf, subject);
-		else if (commit)
-			format_commit_message(commit, "%f", buf, &ctx);
+	if (max_len < filename->len)
+		strbuf_setlen(filename, max_len);
+	strbuf_addstr(filename, suffix);
+}
 
-		if (max_len < buf->len)
-			strbuf_setlen(buf, max_len);
-		strbuf_addstr(buf, suffix);
-	}
+void fmt_output_commit(struct strbuf *filename,
+		       struct commit *commit,
+		       struct rev_info *info)
+{
+	struct pretty_print_context ctx = {0};
+	struct strbuf subject = STRBUF_INIT;
+
+	format_commit_message(commit, "%f", &subject, &ctx);
+	fmt_output_subject(filename, subject.buf, info);
+	strbuf_release(&subject);
 }
 
 void log_write_email_headers(struct rev_info *opt, struct commit *commit,
@@ -387,8 +395,10 @@ void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 			 mime_boundary_leader, opt->mime_boundary);
 		extra_headers = subject_buffer;
 
-		get_patch_filename(opt->numbered_files ? NULL : commit, NULL,
-				   opt->nr, opt->patch_suffix, &filename);
+		if (opt->numbered_files)
+			strbuf_addf(&filename, "%d", opt->nr);
+		else
+			fmt_output_commit(&filename, commit, opt);
 		snprintf(buffer, sizeof(buffer) - 1,
 			 "\n--%s%s\n"
 			 "Content-Type: text/x-patch;"
diff --git a/log-tree.h b/log-tree.h
index f5ac238bba..9140f48216 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -21,7 +21,7 @@ void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 void load_ref_decorations(int flags);
 
 #define FORMAT_PATCH_NAME_MAX 64
-void get_patch_filename(struct commit *commit, const char *subject, int nr,
-			const char *suffix, struct strbuf *buf);
+void fmt_output_commit(struct strbuf *, struct commit *, struct rev_info *);
+void fmt_output_subject(struct strbuf *, const char *subject, struct rev_info *);
 
 #endif
diff --git a/revision.h b/revision.h
index 059bfff812..a395c3639a 100644
--- a/revision.h
+++ b/revision.h
@@ -135,6 +135,7 @@ struct rev_info {
 	const char	*mime_boundary;
 	const char	*patch_suffix;
 	int		numbered_files;
+	int		reroll_count;
 	char		*message_id;
 	struct string_list *ref_message_ids;
 	const char	*add_signoff;
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index dc0d8ae928..7fa3647514 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -271,6 +271,22 @@ test_expect_success 'multiple files' '
 	ls patches/0001-Side-changes-1.patch patches/0002-Side-changes-2.patch patches/0003-Side-changes-3-with-n-backslash-n-in-it.patch
 '
 
+test_expect_success 'reroll count' '
+	rm -fr patches &&
+	git format-patch -o patches --cover-letter --reroll-count 4 master..side >list &&
+	! grep -v "^patches/v4-000[0-3]-" list &&
+	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
+	! grep -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
+'
+
+test_expect_success 'reroll count (-v)' '
+	rm -fr patches &&
+	git format-patch -o patches --cover-letter -v4 master..side >list &&
+	! grep -v "^patches/v4-000[0-3]-" list &&
+	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
+	! grep -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
+'
+
 check_threading () {
 	expect="$1" &&
 	shift &&