Re: [PATCH 1/2 v2] btrfs: device add must be sysloged

[Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>]

(2014/07/02 10:37), Anand Jain wrote:
> when we add a new disk to the mounted btrfs we don't record it
> as of now, disk add is a critical change of btrfs configuration,
> it must be recorded in the syslog to help offline investigations
> of customer problems when reported.
> 
> Signed-off-by: Anand Jain <Anand.Jain@oracle.com>
> Reviewed-by: David Sterba <dsterba@suse.cz>

Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Tested-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>

test result:
  3.16-rc3: failed
  3.16-rc3 with this patch: success

===============================================================================
#!/bin/sh

TEST_DEV1=/dev/vdb
TEST_DEV2=/dev/vdc
TEST_MNT=/home/sat/mnt

umount $TEST_MNT
mkfs.btrfs -f $TEST_DEV1
dmesg >dmesg.old

mount $TEST_DEV1 $TEST_MNT
btrfs dev add -f $TEST_DEV2 $TEST_MNT
if [ $? -ne 0 ] ; then
    echo "[ERROR] failed to btrfs dev add." >&2
    exit 1
fi

btrfs dev del $TEST_DEV2 $TEST_MNT
if [ $? -ne 0 ] ; then
    echo "[ERROR] failed to btrfs dev delete" >&2
    exit 1
fi

dmesg >dmesg.new
diff dmesg.old dmesg.new | grep '^>' >dmesg.diff

RET=0
TEST_DEV1_BASE=$(basename $TEST_DEV1)
if grep -q "BTRFS info (device $TEST_DEV1_BASE): device added $TEST_DEV2" dmesg.diff ; then
    echo "[PASS] btrfs device add is logged." >&2
else
    echo "[FAIL] btrfs device add is not logged." >&2
    RET=1
fi
    
if grep -q "BTRFS info (device $TEST_DEV1_BASE): device deleted $TEST_DEV2" dmesg.diff ; then
    echo "[PASS] btrfs device delete is logged." >&2
else
    echo "[FAIL] btrfs device delete is not logged." >&2
    RET=1
fi

rm dmesg.{new,old,diff}
umount $TEST_MNT

exit $RET
===============================================================================

Thanks,
Satoru

> ---
>   v2: Accepts David's review comment, thanks
> 
>   fs/btrfs/ioctl.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 86d5474..4e10259 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -2488,6 +2488,10 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
>   	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
>   	ret = btrfs_init_new_device(root, vol_args->name);
>   
> +	if (!ret)
> +		btrfs_info(root->fs_info, "device added %s",
> +						vol_args->name);
> +
>   	kfree(vol_args);
>   out:
>   	mutex_unlock(&root->fs_info->volume_mutex);
>