e2image: attempt to use ftruncate64 to set i_size for raw images

If ftruncate64() exists, try to use it to set i_size.  This isn't
guaranteed to work, per SuSv3, but if it doesn't work, it's guaranteed
to return an error.  So for file systems and/or operating systems that
don't support extending i_size via ftruncate64(), fall back to writing
the trailing null.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/misc/e2image.c b/misc/e2image.c
index 3cb92fe..93359cf 100644 (file)
--- a/misc/e2image.c
+++ b/misc/e2image.c
@@ -510,8 +510,19 @@ static void output_meta_data_blocks(ext2_filsys fs, int fd)
                        }
                }
        }
+#ifdef HAVE_FTRUNCATE64
+       if (sparse) {
+               ext2_loff_t offset = ext2fs_llseek(fd, sparse, SEEK_CUR);
+
+               if (offset < 0)
+                       lseek_error_and_exit(errno);
+               if (ftruncate64(fd, offset) < 0)
+                       write_block(fd, zero_buf, -1, 1, -1);
+       }
+#else
        if (sparse)
                write_block(fd, zero_buf, sparse-1, 1, -1);
+#endif
        ext2fs_free_mem(&zero_buf);
        ext2fs_free_mem(&buf);
 }