diff --git a/cache.h b/cache.h
index 95ce0a9f7b29b2..a04a4d35765d15 100644
--- a/cache.h
+++ b/cache.h
@@ -1023,12 +1023,16 @@ struct checkout {
 extern int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath);
 
 struct cache_def {
-	char path[PATH_MAX + 1];
-	int len;
+	struct strbuf path;
 	int flags;
 	int track_flags;
 	int prefix_len_stat_func;
 };
+#define CACHE_DEF_INIT { STRBUF_INIT, 0, 0, 0 }
+static inline void cache_def_clear(struct cache_def *cache)
+{
+	strbuf_release(&cache->path);
+}
 
 extern int has_symlink_leading_path(const char *name, int len);
 extern int threaded_has_symlink_leading_path(struct cache_def *, const char *, int);
diff --git a/compat/mingw.c b/compat/mingw.c
index 4fa10aa5ca32b1..e4a8671dfb145c 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -560,7 +560,7 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 static int do_stat_internal(int follow, const char *file_name, struct stat *buf)
 {
 	int namelen;
-	char alt_name[PATH_MAX];
+	char alt_name[MAX_LONG_PATH];
 
 	if (!do_lstat(follow, file_name, buf))
 		return 0;
@@ -576,7 +576,7 @@ static int do_stat_internal(int follow, const char *file_name, struct stat *buf)
 		return -1;
 	while (namelen && file_name[namelen-1] == '/')
 		--namelen;
-	if (!namelen || namelen >= PATH_MAX)
+	if (!namelen || namelen >= MAX_LONG_PATH)
 		return -1;
 
 	memcpy(alt_name, file_name, namelen);
diff --git a/dir.c b/dir.c
index 98bb50fbabb69d..c927114fddd021 100644
--- a/dir.c
+++ b/dir.c
@@ -531,8 +531,7 @@ int add_excludes_from_file_to_list(const char *fname,
 			buf = xrealloc(buf, size+1);
 			buf[size++] = '\n';
 		}
-	}
-	else {
+	} else {
 		size = xsize_t(st.st_size);
 		if (size == 0) {
 			close(fd);
@@ -766,17 +765,19 @@ static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
 
 	group = &dir->exclude_list_group[EXC_DIRS];
 
-	/* Pop the exclude lists from the EXCL_DIRS exclude_list_group
+	/*
+	 * Pop the exclude lists from the EXCL_DIRS exclude_list_group
 	 * which originate from directories not in the prefix of the
-	 * path being checked. */
+	 * path being checked.
+	 */
 	while ((stk = dir->exclude_stack) != NULL) {
 		if (stk->baselen <= baselen &&
-		    !strncmp(dir->basebuf, base, stk->baselen))
+		    !strncmp(dir->basebuf.buf, base, stk->baselen))
 			break;
 		el = &group->el[dir->exclude_stack->exclude_ix];
 		dir->exclude_stack = stk->prev;
 		dir->exclude = NULL;
-		free((char *)el->src); /* see strdup() below */
+		free((char *)el->src); /* see strbuf_detach() below */
 		clear_exclude_list(el);
 		free(stk);
 		group->nr--;
@@ -786,8 +787,17 @@ static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
 	if (dir->exclude)
 		return;
 
+	/*
+	 * Lazy initialization. All call sites currently just
+	 * memset(dir, 0, sizeof(*dir)) before use. Changing all of
+	 * them seems lots of work for little benefit.
+	 */
+	if (!dir->basebuf.buf)
+		strbuf_init(&dir->basebuf, PATH_MAX);
+
 	/* Read from the parent directories and push them down. */
 	current = stk ? stk->baselen : -1;
+	strbuf_setlen(&dir->basebuf, current < 0 ? 0 : current);
 	while (current < baselen) {
 		struct exclude_stack *stk = xcalloc(1, sizeof(*stk));
 		const char *cp;
@@ -795,8 +805,7 @@ static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
 		if (current < 0) {
 			cp = base;
 			current = 0;
-		}
-		else {
+		} else {
 			cp = strchr(base + current + 1, '/');
 			if (!cp)
 				die("oops in prep_exclude");
@@ -806,48 +815,47 @@ static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
 		stk->baselen = cp - base;
 		stk->exclude_ix = group->nr;
 		el = add_exclude_list(dir, EXC_DIRS, NULL);
-		memcpy(dir->basebuf + current, base + current,
-		       stk->baselen - current);
+		strbuf_add(&dir->basebuf, base + current, stk->baselen - current);
+		assert(stk->baselen == dir->basebuf.len);
 
 		/* Abort if the directory is excluded */
 		if (stk->baselen) {
 			int dt = DT_DIR;
-			dir->basebuf[stk->baselen - 1] = 0;
+			dir->basebuf.buf[stk->baselen - 1] = 0;
 			dir->exclude = last_exclude_matching_from_lists(dir,
-				dir->basebuf, stk->baselen - 1,
-				dir->basebuf + current, &dt);
-			dir->basebuf[stk->baselen - 1] = '/';
+				dir->basebuf.buf, stk->baselen - 1,
+				dir->basebuf.buf + current, &dt);
+			dir->basebuf.buf[stk->baselen - 1] = '/';
 			if (dir->exclude &&
 			    dir->exclude->flags & EXC_FLAG_NEGATIVE)
 				dir->exclude = NULL;
 			if (dir->exclude) {
-				dir->basebuf[stk->baselen] = 0;
 				dir->exclude_stack = stk;
 				return;
 			}
 		}
 
-		/* Try to read per-directory file unless path is too long */
-		if (dir->exclude_per_dir &&
-		    stk->baselen + strlen(dir->exclude_per_dir) < PATH_MAX) {
-			strcpy(dir->basebuf + stk->baselen,
-					dir->exclude_per_dir);
+		/* Try to read per-directory file */
+		if (dir->exclude_per_dir) {
 			/*
 			 * dir->basebuf gets reused by the traversal, but we
 			 * need fname to remain unchanged to ensure the src
 			 * member of each struct exclude correctly
 			 * back-references its source file.  Other invocations
 			 * of add_exclude_list provide stable strings, so we
-			 * strdup() and free() here in the caller.
+			 * strbuf_detach() and free() here in the caller.
 			 */
-			el->src = strdup(dir->basebuf);
-			add_excludes_from_file_to_list(dir->basebuf,
-					dir->basebuf, stk->baselen, el, 1);
+			struct strbuf sb = STRBUF_INIT;
+			strbuf_addbuf(&sb, &dir->basebuf);
+			strbuf_addstr(&sb, dir->exclude_per_dir);
+			el->src = strbuf_detach(&sb, NULL);
+			add_excludes_from_file_to_list(el->src, el->src,
+						       stk->baselen, el, 1);
 		}
 		dir->exclude_stack = stk;
 		current = stk->baselen;
 	}
-	dir->basebuf[baselen] = '\0';
+	strbuf_setlen(&dir->basebuf, baselen);
 }
 
 /*
@@ -1648,4 +1656,5 @@ void clear_directory(struct dir_struct *dir)
 		free(stk);
 		stk = prev;
 	}
+	strbuf_release(&dir->basebuf);
 }
diff --git a/dir.h b/dir.h
index 55e53456afab4c..6c45e9d4b9a905 100644
--- a/dir.h
+++ b/dir.h
@@ -15,6 +15,27 @@ struct dir_entry {
 #define EXC_FLAG_MUSTBEDIR 8
 #define EXC_FLAG_NEGATIVE 16
 
+struct exclude {
+	/*
+	 * This allows callers of last_exclude_matching() etc.
+	 * to determine the origin of the matching pattern.
+	 */
+	struct exclude_list *el;
+
+	const char *pattern;
+	int patternlen;
+	int nowildcardlen;
+	const char *base;
+	int baselen;
+	int flags;
+
+	/*
+	 * Counting starts from 1 for line numbers in ignore files,
+	 * and from -1 decrementing for patterns from CLI args.
+	 */
+	int srcpos;
+};
+
 /*
  * Each excludes file will be parsed into a fresh exclude_list which
  * is appended to the relevant exclude_list_group (either EXC_DIRS or
@@ -32,26 +53,7 @@ struct exclude_list {
 	/* origin of list, e.g. path to filename, or descriptive string */
 	const char *src;
 
-	struct exclude {
-		/*
-		 * This allows callers of last_exclude_matching() etc.
-		 * to determine the origin of the matching pattern.
-		 */
-		struct exclude_list *el;
-
-		const char *pattern;
-		int patternlen;
-		int nowildcardlen;
-		const char *base;
-		int baselen;
-		int flags;
-
-		/*
-		 * Counting starts from 1 for line numbers in ignore files,
-		 * and from -1 decrementing for patterns from CLI args.
-		 */
-		int srcpos;
-	} **excludes;
+	struct exclude **excludes;
 };
 
 /*
@@ -117,7 +119,7 @@ struct dir_struct {
 	 */
 	struct exclude_stack *exclude_stack;
 	struct exclude *exclude;
-	char basebuf[PATH_MAX];
+	struct strbuf basebuf;
 };
 
 /*
diff --git a/preload-index.c b/preload-index.c
index 8253778c85d7c7..c7970d7cb95587 100644
--- a/preload-index.c
+++ b/preload-index.c
@@ -37,9 +37,8 @@ static void *preload_thread(void *_data)
 	struct thread_data *p = _data;
 	struct index_state *index = p->index;
 	struct cache_entry **cep = index->cache + p->offset;
-	struct cache_def cache;
+	struct cache_def cache = CACHE_DEF_INIT;
 
-	memset(&cache, 0, sizeof(cache));
 	nr = p->nr;
 	if (nr + p->offset > index->cache_nr)
 		nr = index->cache_nr - p->offset;
@@ -64,6 +63,7 @@ static void *preload_thread(void *_data)
 			continue;
 		ce_mark_uptodate(ce);
 	} while (--nr > 0);
+	cache_def_clear(&cache);
 	return NULL;
 }
 
diff --git a/symlinks.c b/symlinks.c
index c2b41a85013eec..5261e8cf499006 100644
--- a/symlinks.c
+++ b/symlinks.c
@@ -35,12 +35,11 @@ static int longest_path_match(const char *name_a, int len_a,
 	return match_len;
 }
 
-static struct cache_def default_cache;
+static struct cache_def default_cache = CACHE_DEF_INIT;
 
 static inline void reset_lstat_cache(struct cache_def *cache)
 {
-	cache->path[0] = '\0';
-	cache->len = 0;
+	strbuf_reset(&cache->path);
 	cache->flags = 0;
 	/*
 	 * The track_flags and prefix_len_stat_func members is only
@@ -73,7 +72,7 @@ static int lstat_cache_matchlen(struct cache_def *cache,
 				int prefix_len_stat_func)
 {
 	int match_len, last_slash, last_slash_dir, previous_slash;
-	int save_flags, max_len, ret;
+	int save_flags, ret;
 	struct stat st;
 
 	if (cache->track_flags != track_flags ||
@@ -93,14 +92,14 @@ static int lstat_cache_matchlen(struct cache_def *cache,
 		 * the 2 "excluding" path types.
 		 */
 		match_len = last_slash =
-			longest_path_match(name, len, cache->path, cache->len,
-					   &previous_slash);
+			longest_path_match(name, len, cache->path.buf,
+					   cache->path.len, &previous_slash);
 		*ret_flags = cache->flags & track_flags & (FL_NOENT|FL_SYMLINK);
 
 		if (!(track_flags & FL_FULLPATH) && match_len == len)
 			match_len = last_slash = previous_slash;
 
-		if (*ret_flags && match_len == cache->len)
+		if (*ret_flags && match_len == cache->path.len)
 			return match_len;
 		/*
 		 * If we now have match_len > 0, we would know that
@@ -121,21 +120,22 @@ static int lstat_cache_matchlen(struct cache_def *cache,
 	 */
 	*ret_flags = FL_DIR;
 	last_slash_dir = last_slash;
-	max_len = len < PATH_MAX ? len : PATH_MAX;
-	while (match_len < max_len) {
+	if (len > cache->path.len)
+		strbuf_grow(&cache->path, len - cache->path.len);
+	while (match_len < len) {
 		do {
-			cache->path[match_len] = name[match_len];
+			cache->path.buf[match_len] = name[match_len];
 			match_len++;
-		} while (match_len < max_len && name[match_len] != '/');
-		if (match_len >= max_len && !(track_flags & FL_FULLPATH))
+		} while (match_len < len && name[match_len] != '/');
+		if (match_len >= len && !(track_flags & FL_FULLPATH))
 			break;
 		last_slash = match_len;
-		cache->path[last_slash] = '\0';
+		cache->path.buf[last_slash] = '\0';
 
 		if (last_slash <= prefix_len_stat_func)
-			ret = stat(cache->path, &st);
+			ret = stat(cache->path.buf, &st);
 		else
-			ret = lstat(cache->path, &st);
+			ret = lstat(cache->path.buf, &st);
 
 		if (ret) {
 			*ret_flags = FL_LSTATERR;
@@ -158,12 +158,11 @@ static int lstat_cache_matchlen(struct cache_def *cache,
 	 * for the moment!
 	 */
 	save_flags = *ret_flags & track_flags & (FL_NOENT|FL_SYMLINK);
-	if (save_flags && last_slash > 0 && last_slash <= PATH_MAX) {
-		cache->path[last_slash] = '\0';
-		cache->len = last_slash;
+	if (save_flags && last_slash > 0) {
+		cache->path.buf[last_slash] = '\0';
+		cache->path.len = last_slash;
 		cache->flags = save_flags;
-	} else if ((track_flags & FL_DIR) &&
-		   last_slash_dir > 0 && last_slash_dir <= PATH_MAX) {
+	} else if ((track_flags & FL_DIR) && last_slash_dir > 0) {
 		/*
 		 * We have a separate test for the directory case,
 		 * since it could be that we have found a symlink or a
@@ -175,8 +174,8 @@ static int lstat_cache_matchlen(struct cache_def *cache,
 		 * can still cache the path components before the last
 		 * one (the found symlink or non-existing component).
 		 */
-		cache->path[last_slash_dir] = '\0';
-		cache->len = last_slash_dir;
+		cache->path.buf[last_slash_dir] = '\0';
+		cache->path.len = last_slash_dir;
 		cache->flags = FL_DIR;
 	} else {
 		reset_lstat_cache(cache);
@@ -273,21 +272,18 @@ static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name
 		FL_DIR;
 }
 
-static struct removal_def {
-	char path[PATH_MAX];
-	int len;
-} removal;
+static struct strbuf removal = STRBUF_INIT;
 
 static void do_remove_scheduled_dirs(int new_len)
 {
 	while (removal.len > new_len) {
-		removal.path[removal.len] = '\0';
-		if (rmdir(removal.path))
+		removal.buf[removal.len] = '\0';
+		if (rmdir(removal.buf))
 			break;
 		do {
 			removal.len--;
 		} while (removal.len > new_len &&
-			 removal.path[removal.len] != '/');
+			 removal.buf[removal.len] != '/');
 	}
 	removal.len = new_len;
 }
@@ -297,7 +293,7 @@ void schedule_dir_for_removal(const char *name, int len)
 	int match_len, last_slash, i, previous_slash;
 
 	match_len = last_slash = i =
-		longest_path_match(name, len, removal.path, removal.len,
+		longest_path_match(name, len, removal.buf, removal.len,
 				   &previous_slash);
 	/* Find last slash inside 'name' */
 	while (i < len) {
@@ -317,11 +313,8 @@ void schedule_dir_for_removal(const char *name, int len)
 	 * If we go deeper down the directory tree, we only need to
 	 * save the new path components as we go down.
 	 */
-	if (match_len < last_slash) {
-		memcpy(&removal.path[match_len], &name[match_len],
-		       last_slash - match_len);
-		removal.len = last_slash;
-	}
+	if (match_len < last_slash)
+		strbuf_add(&removal, &name[match_len], last_slash - match_len);
 }
 
 void remove_scheduled_dirs(void)