From: Davidlohr Bueso <dave@gnu.org>
Date: Sat, 27 Oct 2012 17:23:36 +0000 (+0200)
Subject: fdisk: gpt: write entire first sector
X-Git-Tag: v2.23-rc1~568
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1961311196cdc290d5e0951f29882d42e01dadd9;p=thirdparty%2Futil-linux.git

fdisk: gpt: write entire first sector

We were writing only 1 byte in LBA0, and GPT requires dealing with an entire
sector. This bug wasn't affecting when dealing with already existing devices
with GPT as we weren't writing an important part of the first sector, thus
leaving it unchanged. Also use write_all() wrapper from all-io.h

Acked-by: Petr Uzel <petr.uzel@suse.cz>
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
---

diff --git a/fdisks/gpt.c b/fdisks/gpt.c
index 40cadb1cdc..48397f3135 100644
--- a/fdisks/gpt.c
+++ b/fdisks/gpt.c
@@ -44,6 +44,7 @@
 #include "blkdev.h"
 #include "bitops.h"
 #include "strutils.h"
+#include "all-io.h"
 
 #define GPT_HEADER_SIGNATURE 0x5452415020494645LL /* EFI PART */
 #define GPT_HEADER_REVISION_V1_02 0x00010200
@@ -1057,8 +1058,10 @@ static int gpt_write_pmbr(struct fdisk_context *cxt)
 	if (offset != lseek(cxt->dev_fd, offset, SEEK_SET))
 		goto fail;
 
-	if (1 == write(cxt->dev_fd, pmbr, 1))
-		return 0;
+	/* pMBR covers the first sector (LBA) of the disk */
+	if (write_all(cxt->dev_fd, pmbr, cxt->sector_size))
+		goto fail;
+	return 0;
 fail:
 	return -errno;
 }