Re: [PATCH] Remove DASD restriction on _disk_sync_part_table (#651478)

[Jim Meyering]

Brian C. Lane wrote:
> ---
>  libparted/arch/linux.c |   23 ++---------------------
>  1 files changed, 2 insertions(+), 21 deletions(-)
>
> diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
> index 38f4e31..435cb46 100644
> --- a/libparted/arch/linux.c
> +++ b/libparted/arch/linux.c
...
> @@ -2807,14 +2794,8 @@ linux_disk_commit (PedDisk* disk)
>                   * created.  Therefore, if using DevFS, we must get the 
> kernel
>                   * to re-read and grok the partition table.
>                   */
> -                /* Work around kernel dasd problem so we really do BLKRRPART 
> */
> -             int ok = 1;
> -             if (disk->dev->type != PED_DEVICE_DASD && _have_blkpg ()) {
> -                     if (!_disk_sync_part_table (disk))
> -                       ok = 0;
> -             }
> -
> -                return ok;
> +                if (!_disk_sync_part_table (disk))
> +                    return 0;
>          }
>
>          return 1;

Thanks, Brian.
I've adjusted your patch to retain _have_blkpg,
so that if someone tries to build on pre-2.4.x, they'll
get a failed assertion rather than subtle misbehavior,
and added a note to remove the assertion in a year or two.

I'll push something like the following after I write a test
to exercise this fix.

>From 1eb86eb4ea1f9961530cc4f209c3f468a6b6c73c Mon Sep 17 00:00:00 2001
From: Brian C. Lane <address@hidden>
Date: Mon, 22 Nov 2010 10:01:56 +0100
Subject: [PATCH] linux: remove DASD restriction on _disk_sync_part_table

* libparted/arch/linux.c: Include <assert.h>.
(linux_disk_commit): Assert that _have_blkpg returns true
and don't skip _disk_sync_part_table for DASD devices.
Otherwise, when creating a partition on a DASD device,
new /dev/*[12...] device files would not be created.
For details, see http://bugzilla.redhat.com/651478.
---
 libparted/arch/linux.c |   18 ++++++++++--------
 1 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index a5ae10c..0807c8b 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -40,6 +40,7 @@
 #include <sys/types.h>
 #include <sys/utsname.h>        /* for uname() */
 #include <scsi/scsi.h>
+#include <assert.h>
 #ifdef ENABLE_DEVICE_MAPPER
 #include <libdevmapper.h>
 #endif
@@ -2824,20 +2825,21 @@ linux_disk_commit (PedDisk* disk)
                 return _dm_reread_part_table (disk);
 #endif
         if (disk->dev->type != PED_DEVICE_FILE) {
+
+               /* We now require BLKPG support.  If this assertion fails,
+                  please write to the mailing list describing your system.
+                  Assuming it's never triggered, ...
+                  FIXME: remove this assertion in 2012.  */
+               assert (_have_blkpg ());
+
                 /* The ioctl() command BLKPG_ADD_PARTITION does not notify
                  * the devfs system; consequently, /proc/partitions will not
                  * be up to date, and the proper links in /dev are not
                  * created.  Therefore, if using DevFS, we must get the kernel
                  * to re-read and grok the partition table.
                  */
-                /* Work around kernel dasd problem so we really do BLKRRPART */
-               int ok = 1;
-               if (disk->dev->type != PED_DEVICE_DASD && _have_blkpg ()) {
-                       if (!_disk_sync_part_table (disk))
-                         ok = 0;
-               }
-
-                return ok;
+               if (!_disk_sync_part_table (disk))
+                       return 0;
         }

         return 1;
--
1.7.3.2.765.g642a8