From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 17 Feb 2012 14:23:12 +0000 (-0500)
Subject: e2image: attempt to use ftruncate64 to set i_size for raw images
X-Git-Tag: v1.42.1~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50a676e944356e188917f5174a7478817024213c;p=thirdparty%2Fe2fsprogs.git

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 3cb92fee2..93359cf5a 100644
--- 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);
 }