Re: [PATCH parted] linux: Treat loopback devices as files

[Jim Meyering]

Hans de Goede wrote:
> We cannot do partition related ioctl's on loopback devices, so
> treat them as files.
>
> * libparted/arch/linux.c(LOOP_MAJOR): New define.
> * libparted/arch/linux.c(_device_probe_type): Treat loopback
> devices as files.
> ---
>  libparted/arch/linux.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
> index 94cbae9..9d15bf2 100644
> --- a/libparted/arch/linux.c
> +++ b/libparted/arch/linux.c
> @@ -254,6 +254,7 @@ struct blkdev_ioctl_param {
>  #define SX8_MAJOR2              161
>  #define XVD_MAJOR               202
>  #define SDMMC_MAJOR             179
> +#define LOOP_MAJOR              7
>
>  #define SCSI_BLK_MAJOR(M) (                                             \
>                  (M) == SCSI_DISK0_MAJOR                                 \
> @@ -569,6 +570,8 @@ _device_probe_type (PedDevice* dev)
>                  dev->type = PED_DEVICE_SDMMC;
>          } else if (_is_virtblk_major(dev_major)) {
>                  dev->type = PED_DEVICE_VIRTBLK;
> +        } else if (dev_major == LOOP_MAJOR) {
> +                dev->type = PED_DEVICE_FILE;
>          } else {
>                  dev->type = PED_DEVICE_UNKNOWN;
>          }

Thank you!
I've adjusted the log message, added a NEWS entry
and fixed the tests/t8000-loop.sh test to pass
with this new behavior:

>From 1983b7b517604aade6a317e8384bd5a58f8e20f5 Mon Sep 17 00:00:00 2001
From: Hans de Goede <address@hidden>
Date: Fri, 11 Dec 2009 11:24:52 +0100
Subject: [PATCH 1/2] linux: treat loopback devices as files

We cannot do partition related ioctl's on loopback devices,
so treat them as files.
* libparted/arch/linux.c (LOOP_MAJOR): Define.
* libparted/arch/linux.c (_device_probe_type): Treat loopback
devices as files.
Reported by Josef Bacik in http://bugzilla.redhat.com/546622
---
 libparted/arch/linux.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index 94cbae9..9d15bf2 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -254,6 +254,7 @@ struct blkdev_ioctl_param {
 #define SX8_MAJOR2              161
 #define XVD_MAJOR               202
 #define SDMMC_MAJOR             179
+#define LOOP_MAJOR              7

 #define SCSI_BLK_MAJOR(M) (                                             \
                 (M) == SCSI_DISK0_MAJOR                                 \
@@ -569,6 +570,8 @@ _device_probe_type (PedDevice* dev)
                 dev->type = PED_DEVICE_SDMMC;
         } else if (_is_virtblk_major(dev_major)) {
                 dev->type = PED_DEVICE_VIRTBLK;
+        } else if (dev_major == LOOP_MAJOR) {
+                dev->type = PED_DEVICE_FILE;
         } else {
                 dev->type = PED_DEVICE_UNKNOWN;
         }
--
1.6.6.rc1.319.g9b57d


>From 6792f263d47f9550869fde3a751aaf7349b91c0a Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Fri, 11 Dec 2009 16:56:45 +0100
Subject: [PATCH 2/2] tests: ensure that parted can partition a loop device

* tests/t8000-loop.sh: Reverse sense of tests, now that
partitioning a loop device succeeds again.
* NEWS (Bug fixes): Mention it.
---
 NEWS                |    4 ++++
 tests/t8000-loop.sh |   28 ++++++++--------------------
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/NEWS b/NEWS
index cd67678..b3d69bc 100644
--- a/NEWS
+++ b/NEWS
@@ -56,6 +56,10 @@ GNU parted NEWS                                    -*- 
outline -*-

 ** Bug fixes

+  parted can once again create partition tables on loop devices.
+  Before, "parted -s /dev/loop0 mklabel gpt" would fail.
+  [bug introduced in parted-1.9.0]
+
   improved >512-byte sector support: for example, printing a table on a
   4k-sector disk would show "Sector size (logical/physical): 4096B/512B",
   when the sizes should have been "4096B/4096B".
diff --git a/tests/t8000-loop.sh b/tests/t8000-loop.sh
index de4378a..e8c27fe 100755
--- a/tests/t8000-loop.sh
+++ b/tests/t8000-loop.sh
@@ -25,37 +25,25 @@ fi
 . $srcdir/t-lib.sh

 require_root_
-lvm_init_root_dir_

-d1=
+d1= f1=
 cleanup_()
 {
   test -n "$d1" && losetup -d "$d1"
-  rm -f "$f1";
+  rm -f "$f1"
 }

 f1=$(pwd)/1; d1=$(loop_setup_ "$f1") \
   || skip_test_ "is this partition mounted with 'nodev'?"

-printf '%s\n' \
-    'Warning: WARNING: the kernel failed to re-read the partition table on' \
-  > exp || framework_failure
-
 fail=0

-# Expect this to exit with status of 1.
-parted -s $d1 mklabel msdos > err 2>&1
-test $? = 1 || fail=1
-sed 's/^\(Warn.*table on\).*/\1/' err > k && mv k err || fail=1
-
-compare exp err || fail=1
-
-# Create a partition; expect to exit 1
-parted -s $d1 mkpart primary 1 10 > err 2>&1
-test $? = 1 || fail=1
-sed 's/^\(Warn.*table on\).*/\1/' err > k && mv k err || fail=1
+# Expect this to succeed.
+parted -s $d1 mklabel msdos > err 2>&1 || fail=1
+compare err /dev/null || fail=1     # expect no output

-# check for expected output
-compare exp err || fail=1
+# Create a partition
+parted -s $d1 mkpart primary 1 10 > err 2>&1 || fail=1
+compare err /dev/null || fail=1     # expect no output

 Exit $fail
--
1.6.6.rc1.319.g9b57d