From b83ac74a8b87a770bdd78c7c23731bcc252393e4 Mon Sep 17 00:00:00 2001 From: Phillip Susi Date: Fri, 2 May 2014 21:50:50 -0400 Subject: [PATCH 207/208] libparted: don't trash filesystem when writing loop label If you deleted the fake partition on a loop label, loop_write() would write the loop signature to the device, zeroing out all other bytes in the first sector. When the disk contained an ext[234] filesystem and was using 2k sectors, this would trash the super block residing in the 1-2kb part of the sector causing the disk to become unrecognized. Instead, read the existing sector and only modify the first few bytes that contain the loop label. --- libparted/labels/loop.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libparted/labels/loop.c b/libparted/labels/loop.c index 8ebb1f4..98f9f23 100644 --- a/libparted/labels/loop.c +++ b/libparted/labels/loop.c @@ -170,7 +170,8 @@ loop_write (const PedDisk* disk) /* if there is already a filesystem on the disk, we don't need to write the signature */ if (part && part->fs_type) return 1; - memset (buf, 0, buflen); + if (!ped_device_read (disk->dev, buf, 0, 1)) + return 0; strcpy (buf, LOOP_SIGNATURE); return ped_device_write (disk->dev, buf, 0, 1); -- 1.9.0