Re: [PATCH 7/7] btrfs: add helper function check device delete able

[Anand Jain <anand.jain@oracle.com>]

On 07/19/2018 07:45 PM, David Sterba wrote:
> On Mon, Jul 16, 2018 at 10:58:12PM +0800, Anand Jain wrote:
>> Move the section of the code which performs the check if the device is
>> indelible, move that into a helper function.
>>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>> ---
>> v1->v2: Rename function to btrfs_get_device_for_delete(), thanks
>> Nikolay.
>>
>>   fs/btrfs/volumes.c | 49 ++++++++++++++++++++++++++++++-------------------
>>   1 file changed, 30 insertions(+), 19 deletions(-)
>>
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index 1c0b56374992..0cefc24b028c 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -1859,6 +1859,33 @@ static inline u64 btrfs_num_devices(struct btrfs_fs_info *fs_info)
>>   	return num_devices;
>>   }
>>   
>> +static struct btrfs_device *btrfs_get_device_for_delete(
>> +				struct btrfs_fs_info *fs_info,
>> +				const char *device_path, u64 devid)
>> +{
>> +	int ret;
>> +	struct btrfs_device *device;
>> +
>> +	ret = btrfs_check_raid_min_devices(fs_info,
>> +					   btrfs_num_devices(fs_info) - 1);
>> +	if (ret)
>> +		return ERR_PTR(ret);
>> +
>> +	ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
>> +					   &device);
>> +	if (ret)
>> +		return ERR_PTR(ret);
>> +
>> +	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
>> +		return ERR_PTR(BTRFS_ERROR_DEV_TGT_REPLACE);
> 
> This is wrong, the BTRFS_ERROR valueas are >= 1, but the IS_ERR, ERR_PTR
> work for errno values -4095..0 .
> 
> Thouth ERR_PTR would cast the integer into pointer, the callers of
> btrfs_get_device_for_delete will not detect the error and continue.

  Argh. Will fix.

Thanks, Anand

>> +
>> +	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
>> +	    fs_info->fs_devices->rw_devices == 1)
>> +		return ERR_PTR(BTRFS_ERROR_DEV_ONLY_WRITABLE);
>> +
>> +	return device;
>> +}
>> +
>>   int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
>>   		u64 devid)
>>   {
>> @@ -1872,25 +1899,9 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
>>   
>>   	mutex_lock(&uuid_mutex);
>>   
>> -	num_devices = btrfs_num_devices(fs_info);
>> -
>> -	ret = btrfs_check_raid_min_devices(fs_info, num_devices - 1);
>> -	if (ret)
>> -		goto out;
>> -
>> -	ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
>> -					   &device);
>> -	if (ret)
>> -		goto out;
>> -
>> -	if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
>> -		ret = BTRFS_ERROR_DEV_TGT_REPLACE;
>> -		goto out;
>> -	}
>> -
>> -	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
>> -	    fs_info->fs_devices->rw_devices == 1) {
>> -		ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
>> +	device = btrfs_get_device_for_delete(fs_info, device_path, devid);
>> +	if (IS_ERR(device)) {
> 
> BTRFS_ERROR_DEV_ONLY_WRITABLE won't work here.
> 
>> +		ret = PTR_ERR(device);
>>   		goto out;
>>   	}
>>   
>> -- 
>> 2.7.0
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>