[Parted-commits] GNU Parted Official Repository: Changes to 'master'

[Jim Meyering]

 NEWS                   |    4 ++++
 libparted/labels/dos.c |   14 +++++++-------
 2 files changed, 11 insertions(+), 7 deletions(-)

New commits:
commit 9f5b0608611eed40ef33be2096f5d482710602e5
Author: Jim Meyering <meyering at redhat.com>
Date:   Tue Nov 9 10:25:36 2010 +0100

    dos: fix a bug affecting very small devices (smaller than 1 cylinder)
    
    This bug was introduced in commit c79d91ec, "dos: accommodate very
    small devices (useful for testing)".
    * libparted/labels/dos.c (_primary_constraint): The bug was to
    skip setting start_geom for small devices.  That led to a used-
    uninitialized bug in the subsequent ped_constraint_new call.
    The fix is to relax the constraint to use a starting sector of "1",
    if necessary.  Report and diagnosis by Jean-Christian de Rivaz in
    http://thread.gmane.org/gmane.comp.gnu.parted.bugs/10178
    * NEWS (Bug fixes): Mention it.

diff --git a/NEWS b/NEWS
index 5dd7dca..4979b90 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,10 @@ GNU parted NEWS                                    -*- outline -*-
   libparted now recognizes scsi disks with a high major (128-135) as scsi
   disks
 
+  an msdos partition table on a very small device (smaller than one cylinder)
+  is now recognized.  [bug introduced in parted-2.2]
+
+
 * Noteworthy changes in release 2.3 (2010-05-28) [stable]
 
 ** New features
diff --git a/libparted/labels/dos.c b/libparted/labels/dos.c
index d9e7d4a..578180b 100644
--- a/libparted/labels/dos.c
+++ b/libparted/labels/dos.c
@@ -1713,13 +1713,13 @@ _primary_constraint (const PedDisk* disk, const PedCHSGeometry* bios_geom,
 			       		dev->length - min_geom->end))
 			return NULL;
 	} else {
-		/* Do not assume that length is larger than 1 cylinder's
-		   worth of sectors.  This is useful when testing with
-		   a memory-mapped "disk" (a la scsi_debug) that is say,
-		   2048 sectors long.  */
-		if (cylinder_size < dev->length
-		    && !ped_geometry_init (&start_geom, dev, cylinder_size,
-					   dev->length - cylinder_size))
+		/* Use cylinder_size as the starting sector number
+		   when the device is large enough to accommodate that.
+		   Otherwise, use sector 1.  */
+		PedSector start = (cylinder_size < dev->length
+				   ? cylinder_size : 1);
+		if (!ped_geometry_init (&start_geom, dev, start,
+					dev->length - start))
 			return NULL;
 		if (!ped_geometry_init (&end_geom, dev, 0, dev->length))
 			return NULL;