Re: [PATCH] xfstests: fix device lookup in btrfs/003

[Jeff Mahoney <jeffm@suse.com>]

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On 9/6/13 10:03 AM, David Sterba wrote:
> On Tue, Sep 03, 2013 at 06:19:01PM -0400, Jeff Mahoney wrote:
>> The DEVHTL lookup in btrfs/003 is broken. It can only handle full LUNs and
>> not partitions on a disk.
>>
>> Rather than returning 2:0:0:0 for /dev/sdc7, it returns 'block' and we see:
>> ./common/rc: line 2081: /sys/class/scsi_device/block/device/delete:
>> No such file or directory
>>
>> If we look up the device by dev instead of by name, we can handle working
>> with full disks and partitions more easily and get the ability to use
>> any device name rather than just the ones that match sysfs.
>>
>> @@ -137,9 +137,21 @@ _test_replace()
>>  	#pick the 2nd last disk 
>>  	ds=${devs[@]:$(($n-1)):1}
>>  
>> -	# retrive the HTL for this scsi disk
>> -	d=`echo $ds|cut -d"/" -f3`
>> -	DEVHTL=`ls -l /sys/class/block/${d} | rev | cut -d "/" -f 3 | rev`
>> +	HEXMAJOR="$(stat -c "%t" "$ds")"
>> +	HEXMINOR="$(stat -c "%T" "$ds")"
>> +	if [ -z "$HEXMAJOR" -o -z "$HEXMINOR" ]; then
>> +		_fail "tr: HEXMAJOR and/or HEXMINOR is unset for $ds"
>> +	fi
>> +
>> +	DIR="/sys/dev/block/$(( 0x$HEXMAJOR )):$(( 0x$HEXMINOR ))"
>> +
>> +	if [ -L "$DIR/device" ]; then # whole disk
>> +		DEVHTL="$(basename $(readlink "$DIR/device"))"
>> +	elif [ -L "$DIR/../device" ]; then # partition
>> +		DEVHTL="$(basename $(readlink "$DIR/../device"))"
>> +	else
>> +		_fail "tr: Can't locate device backing $ds"
>> +	fi
>>  
>>  	#fail disk
>>  	_devmgt_remove ${DEVHTL}
> 
> The test assumes tha SCRATCH_DEV_POOL consists of standalone devices
> and more strongly that they can be removed from the system by
> 
> $ echo 1 > /sys/class/scsi_device/sdx/device/delete
> 
> via _devmgt_remove. Ordinary sdX devices are ok, but eg. MD devices are
> not because they do not have a corresponding "2:0:0:0"-like entry (I
> haven't checked device-mapper devices).
> 
> Looks like the tests have to do more fine grained checks of the devices
> in SCRATCH_DEV_POOL because eg. the 'device replace' test btrfs/011 is
> just fine with partitions.

Yeah. It doesn't work with any type of device that doesn't present a
SCSI-style host interface with a delete sysfs entry. I wasn't looking to
make it work everywhere, just allow it to work with the types of devices
it was originally targeting in a slightly less fragile way.

-Jeff

-- 
Jeff Mahoney
SUSE Labs


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