diff --git a/src/error.cpp b/src/error.cpp
index 86f807de2bd4ac3393adf15430bda833b1b8d997..84b78aba1b3ed6f6a870c92fe37e5327e7293366 100644
--- a/src/error.cpp
+++ b/src/error.cpp
@@ -45,6 +45,11 @@ const char *err_str(Error err) {
         case ErrorUnknownOperatingSystem: return "unrecognized operating system";
         case ErrorUnknownABI: return "unrecognized C ABI";
         case ErrorInvalidFilename: return "invalid filename";
+        case ErrorDiskQuota: return "disk space quota exceeded";
+        case ErrorDiskSpace: return "out of disk space";
+        case ErrorUnexpectedWriteFailure: return "unexpected write failure";
+        case ErrorUnexpectedSeekFailure: return "unexpected seek failure";
+        case ErrorUnexpectedFileTruncationFailure: return "unexpected file truncation failure";
     }
     return "(invalid error)";
 }
diff --git a/src/error.hpp b/src/error.hpp
index 8af0d861543c0f40b01b6ef65d242dc8342b1f4b..d943703268a64afebb0b8b02dc0a8f31ae32f5db 100644
--- a/src/error.hpp
+++ b/src/error.hpp
@@ -47,6 +47,11 @@ enum Error {
     ErrorUnknownOperatingSystem,
     ErrorUnknownABI,
     ErrorInvalidFilename,
+    ErrorDiskQuota,
+    ErrorDiskSpace,
+    ErrorUnexpectedWriteFailure,
+    ErrorUnexpectedSeekFailure,
+    ErrorUnexpectedFileTruncationFailure,
 };
 
 const char *err_str(Error err);
diff --git a/src/os.cpp b/src/os.cpp
index 1dd22b71837d14adb6eef8cd3da0323394a97399..470d2223072f084519d460e7201f9c1c07949840 100644
--- a/src/os.cpp
+++ b/src/os.cpp
@@ -2048,9 +2048,9 @@ Error os_file_overwrite(OsFile file, Buf *contents) {
     return ErrorNone;
 #else
     if (lseek(file, 0, SEEK_SET) == -1)
-        return ErrorFileSystem;
+        return ErrorUnexpectedSeekFailure;
     if (ftruncate(file, 0) == -1)
-        return ErrorFileSystem;
+        return ErrorUnexpectedFileTruncationFailure;
     for (;;) {
         if (write(file, buf_ptr(contents), buf_len(contents)) == -1) {
             switch (errno) {
@@ -2060,8 +2060,20 @@ Error os_file_overwrite(OsFile file, Buf *contents) {
                     zig_unreachable();
                 case EBADF:
                     zig_unreachable();
-                default:
+                case EFAULT:
+                    zig_unreachable();
+                case EDQUOT:
+                    return ErrorDiskQuota;
+                case ENOSPC:
+                    return ErrorDiskSpace;
+                case EFBIG:
+                    return ErrorFileTooBig;
+                case EIO:
                     return ErrorFileSystem;
+                case EPERM:
+                    return ErrorAccess;
+                default:
+                    return ErrorUnexpectedWriteFailure;
             }
         }
         return ErrorNone;