diff --git a/Documentation/config/format.txt b/Documentation/config/format.txt
index c2efd8758a..7f6d11b5d5 100644
--- a/Documentation/config/format.txt
+++ b/Documentation/config/format.txt
@@ -94,6 +94,11 @@ format.outputDirectory::
 	Set a custom directory to store the resulting files instead of the
 	current working directory. All directory components will be created.
 
+format.filenameMaxLength::
+	The maximum length of the output filenames generated by the
+	`format-patch` command; defaults to 64.  Can be overridden
+	by the `--filename-max-length=<n>` command line option.
+
 format.useAutoBase::
 	A boolean value which lets you enable the `--base=auto` option of
 	format-patch by default. Can also be set to "whenAble" to allow
diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 0f81d0437b..3347702b71 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -28,6 +28,7 @@ SYNOPSIS
 		   [--no-notes | --notes[=<ref>]]
 		   [--interdiff=<previous>]
 		   [--range-diff=<previous> [--creation-factor=<percent>]]
+		   [--filename-max-length=<n>]
 		   [--progress]
 		   [<common diff options>]
 		   [ <since> | <revision range> ]
@@ -200,6 +201,13 @@ populated with placeholder text.
 	allows for useful naming of a patch series, and can be
 	combined with the `--numbered` option.
 
+--filename-max-length=<n>::
+	Instead of the standard 64 bytes, chomp the generated output
+	filenames at around '<n>' bytes (too short a value will be
+	silently raised to a reasonable length).  Defaults to the
+	value of the `format.filenameMaxLength` configuration
+	variable, or 64 if unconfigured.
+
 --rfc::
 	Alias for `--subject-prefix="RFC PATCH"`. RFC means "Request For
 	Comments"; use this when sending an experimental patch for
diff --git a/builtin/log.c b/builtin/log.c
index 0a7ed4bef9..861ac17da0 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -37,6 +37,7 @@
 
 #define MAIL_DEFAULT_WRAP 72
 #define COVER_FROM_AUTO_MAX_SUBJECT_LEN 100
+#define FORMAT_PATCH_NAME_MAX_DEFAULT 64
 
 /* Set a default date-time format for git log ("log.date" config variable) */
 static const char *default_date_mode = NULL;
@@ -50,6 +51,7 @@ static int decoration_style;
 static int decoration_given;
 static int use_mailmap_config = 1;
 static const char *fmt_patch_subject_prefix = "PATCH";
+static int fmt_patch_name_max = FORMAT_PATCH_NAME_MAX_DEFAULT;
 static const char *fmt_pretty;
 
 static const char * const builtin_log_usage[] = {
@@ -150,6 +152,7 @@ static void cmd_log_init_defaults(struct rev_info *rev)
 	rev->abbrev_commit = default_abbrev_commit;
 	rev->show_root_diff = default_show_root;
 	rev->subject_prefix = fmt_patch_subject_prefix;
+	rev->patch_name_max = fmt_patch_name_max;
 	rev->show_signature = default_show_signature;
 	rev->encode_email_headers = default_encode_email_headers;
 	rev->diffopt.flags.allow_textconv = 1;
@@ -454,6 +457,10 @@ static int git_log_config(const char *var, const char *value, void *cb)
 		return git_config_string(&fmt_pretty, var, value);
 	if (!strcmp(var, "format.subjectprefix"))
 		return git_config_string(&fmt_patch_subject_prefix, var, value);
+	if (!strcmp(var, "format.filenamemaxlength")) {
+		fmt_patch_name_max = git_config_int(var, value);
+		return 0;
+	}
 	if (!strcmp(var, "format.encodeemailheaders")) {
 		default_encode_email_headers = git_config_bool(var, value);
 		return 0;
@@ -955,15 +962,9 @@ static int open_next_file(struct commit *commit, const char *subject,
 			 struct rev_info *rev, int quiet)
 {
 	struct strbuf filename = STRBUF_INIT;
-	int suffix_len = strlen(rev->patch_suffix) + 1;
 
 	if (output_directory) {
 		strbuf_addstr(&filename, output_directory);
-		if (filename.len >=
-		    PATH_MAX - FORMAT_PATCH_NAME_MAX - suffix_len) {
-			strbuf_release(&filename);
-			return error(_("name of output directory is too long"));
-		}
 		strbuf_complete(&filename, '/');
 	}
 
@@ -1751,6 +1752,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 			    N_("start numbering patches at <n> instead of 1")),
 		OPT_INTEGER('v', "reroll-count", &reroll_count,
 			    N_("mark the series as Nth re-roll")),
+		OPT_INTEGER(0, "filename-max-length", &fmt_patch_name_max,
+			    N_("max length of output filename")),
 		OPT_CALLBACK_F(0, "rfc", &rev, NULL,
 			    N_("Use [RFC PATCH] instead of [PATCH]"),
 			    PARSE_OPT_NOARG | PARSE_OPT_NONEG, rfc_callback),
@@ -1822,6 +1825,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	init_display_notes(&notes_opt);
 	git_config(git_format_config, NULL);
 	repo_init_revisions(the_repository, &rev, prefix);
+	rev.subject_prefix = fmt_patch_subject_prefix;
 	rev.show_notes = show_notes;
 	memcpy(&rev.notes_opt, &notes_opt, sizeof(notes_opt));
 	rev.commit_format = CMIT_FMT_EMAIL;
@@ -1831,7 +1835,6 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	rev.diff = 1;
 	rev.max_parents = 1;
 	rev.diffopt.flags.recursive = 1;
-	rev.subject_prefix = fmt_patch_subject_prefix;
 	memset(&s_r_opt, 0, sizeof(s_r_opt));
 	s_r_opt.def = "HEAD";
 	s_r_opt.revarg_opt = REVARG_COMMITTISH;
@@ -1851,6 +1854,10 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN |
 			     PARSE_OPT_KEEP_DASHDASH);
 
+	/* Make sure "0000-$sub.patch" gives non-negative length for $sub */
+	if (fmt_patch_name_max <= strlen("0000-") + strlen(fmt_patch_suffix))
+		fmt_patch_name_max = strlen("0000-") + strlen(fmt_patch_suffix);
+
 	if (cover_from_description_arg)
 		cover_from_description_mode = parse_cover_from_description(cover_from_description_arg);
 
@@ -1935,6 +1942,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
 
 	rev.zero_commit = zero_commit;
+	rev.patch_name_max = fmt_patch_name_max;
 
 	if (!rev.diffopt.flags.text && !no_binary_diff)
 		rev.diffopt.flags.binary = 1;
diff --git a/log-tree.c b/log-tree.c
index 1927f917ce..fd0dde97ec 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -367,7 +367,7 @@ void fmt_output_subject(struct strbuf *filename,
 	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);
+	int max_len = start_len + info->patch_name_max - (strlen(suffix) + 1);
 
 	if (0 < info->reroll_count)
 		strbuf_addf(filename, "v%d-", info->reroll_count);
diff --git a/log-tree.h b/log-tree.h
index 8fa79289ec..1e8c91dbf2 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -33,7 +33,6 @@ void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 			     int maybe_multipart);
 void load_ref_decorations(struct decoration_filter *filter, int flags);
 
-#define FORMAT_PATCH_NAME_MAX 64
 void fmt_output_commit(struct strbuf *, struct commit *, struct rev_info *);
 void fmt_output_subject(struct strbuf *, const char *subject, struct rev_info *);
 void fmt_output_email_subject(struct strbuf *, struct rev_info *);
diff --git a/revision.h b/revision.h
index f6bf860d19..086ff10280 100644
--- a/revision.h
+++ b/revision.h
@@ -238,6 +238,7 @@ struct rev_info {
 	const char	*extra_headers;
 	const char	*log_reencode;
 	const char	*subject_prefix;
+	int		patch_name_max;
 	int		no_inline;
 	int		show_log_size;
 	struct string_list *mailmap;
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 294e76c860..024c0a026d 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -313,6 +313,60 @@ 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 'filename length limit' '
+	test_when_finished "rm -f 000*" &&
+	rm -rf 000[1-9]-*.patch &&
+	for len in 15 25 35
+	do
+		git format-patch --filename-max-length=$len -3 side &&
+		max=$(
+			for patch in 000[1-9]-*.patch
+			do
+				echo "$patch" | wc -c
+			done |
+			sort -nr |
+			head -n 1
+		) &&
+		test $max -le $len || return 1
+	done
+'
+
+test_expect_success 'filename length limit from config' '
+	test_when_finished "rm -f 000*" &&
+	rm -rf 000[1-9]-*.patch &&
+	for len in 15 25 35
+	do
+		git -c format.filenameMaxLength=$len format-patch -3 side &&
+		max=$(
+			for patch in 000[1-9]-*.patch
+			do
+				echo "$patch" | wc -c
+			done |
+			sort -nr |
+			head -n 1
+		) &&
+		test $max -le $len || return 1
+	done
+'
+
+test_expect_success 'filename limit applies only to basename' '
+	test_when_finished "rm -rf patches/" &&
+	rm -rf patches/ &&
+	for len in 15 25 35
+	do
+		git format-patch -o patches --filename-max-length=$len -3 side &&
+		max=$(
+			for patch in patches/000[1-9]-*.patch
+			do
+				echo "${patch#patches/}" | wc -c
+			done |
+			sort -nr |
+			head -n 1
+		) &&
+		test $max -le $len || return 1
+	done
+'
+
 test_expect_success 'reroll count' '
 	rm -fr patches &&
 	git format-patch -o patches --cover-letter --reroll-count 4 master..side >list &&
