diff --git a/os.c b/os.c
index f9e9bd40..11956bbb 100644
--- a/os.c
+++ b/os.c
@@ -230,7 +230,7 @@ int get_file_meta(const char *path, struct file_meta *metap)
     *metap = FILE_META_NONEXIST;
   } else {
     metap->size = st.st_size;
-    metap->mtime = st.st_mtim;
+    metap->mtime.tv_sec = st.st_mtime;
     // Truncate to whole seconds to ensure that this code will work on file systems that only have
     // whole-second time stamp resolution.
     metap->mtime.tv_nsec = 0;
@@ -319,12 +319,14 @@ int alter_file_meta(const char *path, const struct file_meta *origp, struct file
       return 0;
     meta.mtime = origp->mtime;
     add_timespec(&meta.mtime, sec, nsec);
-    struct timespec times[2];
-    times[0].tv_sec = 0;
-    times[0].tv_nsec = UTIME_OMIT;
-    times[1] = meta.mtime;
-    if (utimensat(AT_FDCWD, path, times, 0) == -1)
-      return WHYF_perror("utimensat(AT_FDCWD,%s,[UTIME_OMIT,%s],0)", alloca_str_toprint(path), alloca_timespec(&times[1]));
+    struct timeval times[2];
+    time_ms_t now = gettime_ms();
+    times[0].tv_sec = now / 1000;
+    times[0].tv_usec = (now % 1000) * 1000;
+    times[1].tv_sec = meta.mtime.tv_sec;
+    times[1].tv_usec = meta.mtime.tv_nsec / 1000;
+    if (utimes(path, times) == -1)
+      return WHYF_perror("utimes(%s,[%s,%s])", alloca_str_toprint(path), alloca_timeval(&times[0]), alloca_timeval(&times[1]));
     nsec = 0;
     ++sec;
   }
diff --git a/strbuf_helpers.c b/strbuf_helpers.c
index 3ebbed36..0f5f4bc6 100644
--- a/strbuf_helpers.c
+++ b/strbuf_helpers.c
@@ -460,6 +460,31 @@ strbuf strbuf_append_time_t(strbuf sb, time_t time)
   return sb;
 }
 
+strbuf strbuf_append_time_ms_t(strbuf sb, time_ms_t ms)
+{
+  struct tm tm;
+  time_t time = ms / 1000;
+  localtime_r(&time, &tm);
+  strbuf_append_strftime(sb, "%Y/%m/%d %H:%M:%S", &tm);
+  strbuf_sprintf(sb, ".%.03u", (unsigned)(ms % 1000));
+  strbuf_append_strftime(sb, " %z", &tm);
+  return sb;
+}
+
+strbuf strbuf_append_timeval(strbuf sb, const struct timeval *tv)
+{
+  if (tv->tv_sec < 0 || tv->tv_usec < 0 || tv->tv_usec > 999999) {
+    strbuf_sprintf(sb, "INVALID{tv_sec=%ld,tv_usec=%ld}", (long)tv->tv_sec, (long)tv->tv_usec);
+  } else {
+    struct tm tm;
+    localtime_r(&tv->tv_sec, &tm);
+    strbuf_append_strftime(sb, "%Y/%m/%d %H:%M:%S", &tm);
+    strbuf_sprintf(sb, ".%.06lu", (long)tv->tv_usec);
+    strbuf_append_strftime(sb, " %z", &tm);
+  }
+  return sb;
+}
+
 strbuf strbuf_append_timespec(strbuf sb, const struct timespec *tv)
 {
   if (tv->tv_sec < 0 || tv->tv_nsec < 0 || tv->tv_nsec > 999999999) {
diff --git a/strbuf_helpers.h b/strbuf_helpers.h
index 92820a5f..94bed1bd 100644
--- a/strbuf_helpers.h
+++ b/strbuf_helpers.h
@@ -30,6 +30,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #endif
 
 #include "strbuf.h"
+#include "os.h"
 
 /* Append a representation of the given chars in a given buffer (including nul
  * chars) in printable format, ie, with non-printable characters expanded to \n
@@ -161,18 +162,31 @@ struct iovec;
 strbuf strbuf_append_iovec(strbuf sb, const struct iovec *iov, int iovcnt);
 #define alloca_iovec(iov,cnt)    strbuf_str(strbuf_append_iovec(strbuf_alloca(200), (iov), (cnt)))
 
-/* Append a representation of a time_t value.
+/* Append a representation of a time_t value (second resolution).
  * @author Andrew Bettison <andrew@servalproject.com>
  */
 strbuf strbuf_append_time_t(strbuf sb, time_t);
 #define alloca_time_t(t)    strbuf_str(strbuf_append_time_t(strbuf_alloca(40), (t)))
 
-/* Append a representation of a struct timespec.
+/* Append a representation of a time_ms_t value (millisecond resolution).
+ * @author Andrew Bettison <andrew@servalproject.com>
+ */
+strbuf strbuf_append_time_ms_t(strbuf sb, time_ms_t);
+#define alloca_time_ms_t(t)    strbuf_str(strbuf_append_time_ms_t(strbuf_alloca(45), (t)))
+
+/* Append a representation of a struct timeval (microsecond resolution).
+ * @author Andrew Bettison <andrew@servalproject.com>
+ */
+struct timeval;
+strbuf strbuf_append_timeval(strbuf sb, const struct timeval *tv);
+#define alloca_timeval(tv)    strbuf_str(strbuf_append_timeval(strbuf_alloca(50), (tv)))
+
+/* Append a representation of a struct timespec (nanosecond resolution).
  * @author Andrew Bettison <andrew@servalproject.com>
  */
 struct timespec;
 strbuf strbuf_append_timespec(strbuf sb, const struct timespec *tv);
-#define alloca_timespec(tv)    strbuf_str(strbuf_append_timespec(strbuf_alloca(50), (tv)))
+#define alloca_timespec(tv)    strbuf_str(strbuf_append_timespec(strbuf_alloca(55), (tv)))
 
 /* Append a representation of a struct file_meta.
  * @author Andrew Bettison <andrew@servalproject.com>