diff --git a/src/os/unix/ngx_files.c b/src/os/unix/ngx_files.c
index bb30c1e16..d4bf0436f 100644
--- a/src/os/unix/ngx_files.c
+++ b/src/os/unix/ngx_files.c
@@ -59,26 +59,33 @@ ngx_read_file(ngx_file_t *file, u_char *buf, size_t size, off_t offset)
 ssize_t
 ngx_write_file(ngx_file_t *file, u_char *buf, size_t size, off_t offset)
 {
-    ssize_t  n;
+    ssize_t  n, written;
 
     ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
                    "write: %d, %p, %uz, %O", file->fd, buf, size, offset);
 
+    written = 0;
+
 #if (NGX_HAVE_PWRITE)
 
-    n = pwrite(file->fd, buf, size, offset);
+    for ( ;; ) {
+        n = pwrite(file->fd, buf, size, offset);
 
-    if (n == -1) {
-        ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
-                      "pwrite() \"%s\" failed", file->name.data);
-        return NGX_ERROR;
-    }
+        if (n == -1) {
+            ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
+                          "pwrite() \"%s\" failed", file->name.data);
+            return NGX_ERROR;
+        }
 
-    if ((size_t) n != size) {
-        ngx_log_error(NGX_LOG_CRIT, file->log, 0,
-                      "pwrite() \"%s\" has written only %z of %uz",
-                      file->name.data, n, size);
-        return NGX_ERROR;
+        file->offset += n;
+        written += n;
+
+        if ((size_t) n == size) {
+            return written;
+        }
+
+        offset += n;
+        size -= n;
     }
 
 #else
@@ -93,28 +100,25 @@ ngx_write_file(ngx_file_t *file, u_char *buf, size_t size, off_t offset)
         file->sys_offset = offset;
     }
 
-    n = write(file->fd, buf, size);
+    for ( ;; ) {
+        n = write(file->fd, buf, size);
 
-    if (n == -1) {
-        ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
-                      "write() \"%s\" failed", file->name.data);
-        return NGX_ERROR;
+        if (n == -1) {
+            ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
+                          "write() \"%s\" failed", file->name.data);
+            return NGX_ERROR;
+        }
+
+        file->offset += n;
+        written += n;
+
+        if ((size_t) n == size) {
+            return written;
+        }
+
+        size -= n;
     }
-
-    if ((size_t) n != size) {
-        ngx_log_error(NGX_LOG_CRIT, file->log, 0,
-                      "write() \"%s\" has written only %z of %uz",
-                      file->name.data, n, size);
-        return NGX_ERROR;
-    }
-
-    file->sys_offset += n;
-
 #endif
-
-    file->offset += n;
-
-    return n;
 }