3 files changed, 24 insertions, 0 deletions
diff --git a/src/posix.c b/src/posix.c
index bffe02e05..ef48c6012 100644
--- a/src/posix.c
+++ b/src/posix.c
@@ -216,6 +216,23 @@ int p_write(git_file fd, const void *buf, size_t cnt)
 	return 0;
 }
 
+int p_fallocate(int fd, off_t offset, off_t len)
+{
+#ifdef __APPLE__
+	fstore_t prealloc;
+
+	memset(&prealloc, 0, sizeof(prealloc));
+	prealloc.fst_flags  = F_ALLOCATEALL;
+	prealloc.fst_posmode = F_PEOFPOSMODE;
+	prealloc.fst_offset = offset;
+	prealloc.fst_length = len;
+
+	return fcntl(fd, F_PREALLOCATE, &prealloc);
+#else
+	return posix_fallocate(fd, offset, len);
+#endif
+}
+
 #ifdef NO_MMAP
 
 #include "map.h"
diff --git a/src/posix.h b/src/posix.h
index 2934f2479..0119b6bb7 100644
--- a/src/posix.h
+++ b/src/posix.h
@@ -115,6 +115,7 @@ extern int p_open(const char *path, int flags, ...);
 extern int p_creat(const char *path, mode_t mode);
 extern int p_getcwd(char *buffer_out, size_t size);
 extern int p_rename(const char *from, const char *to);
+extern int p_fallocate(int fd, off_t offset, off_t len);
 
 extern int git__page_size(size_t *page_size);
 extern int git__mmap_alignment(size_t *page_size);
diff --git a/src/win32/posix_w32.c b/src/win32/posix_w32.c
index d8bbebb5d..835804de4 100644
--- a/src/win32/posix_w32.c
+++ b/src/win32/posix_w32.c
@@ -516,6 +516,12 @@ int p_creat(const char *path, mode_t mode)
 	return p_open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
 }
 
+int p_fallocate(int fd, off_t offset, off_t len)
+{
+	error = ENOSYS;
+	return -1;
+}
+
 int p_utimes(const char *path, const struct p_timeval times[2])
 {
 	git_win32_path wpath;