>-----Original Message----- >From: Neil Brown [mailto:neilb@xxxxxxx] >Sent: Friday, November 13, 2009 3:49 AM > >On Thursday November 12, Maciej.Trela@xxxxxxxxx wrote: >> Hello Neil, >> I'm sending the patch that is connected with intel metadata >compatibility. >> >> The new code checks for existing partitions when creating an array. >> If the metadata overwrites the last partition, the warning is shown to >the user. The patch supports only MBR and GPT partition table types. >> Despite the patch was implemented as IMSM compatibility issue I've >decided to include the partition check for all metadata types as a generic >code. >> I would appreciate any feedback. > >Sorry for not responding the first time you posted this. > >I agree with the principle. However I would rather not add code for >reading different partition types to mdadm. It would be much nicer if >that code came from a library. >Is there a good library that we could use? >libparted might be a possibility, but it seems rather over-weight. >/lib/libparted-1.9.so.12.0.0 is larger than /sbin/mdadm !!! > >Are there any other libraries for reading different partition tables? >I guess we can open-code it if we have to but I'd be happy if another >solution could be found. > Hello Neil, I made some research but unfortunately I couldn't find any other library except libparted. Assuming there are no other possibilities, do you think we could stay with the current solution or should I switch the patch to libparted? I have the impression that with libparted this simple patch would be much bigger (given the code size)... >I should probably change to using libblkid to check for the various >filesystem types... > >Is this check really relevant for anything other RAID1 array. For any >other level, the fact that the metadata lies inside or outside the >current partitions is quite irrelevant as the old data will not be >useful anyway. Yes, that's right. However, this check would be also relevant when creating a container with external metadata. Unfortunately in this case we do not know the raid level... Thus, maybe the following condition would be appropriate: if ((raid_level == CONTAINER) || ( !(external) && raid_level==1)) { Check partitions } > >And I don't think it is sensible to report "unknown partition table". >If there is no partition table, there is nothing to check. > >NeilBrown The idea behind this was that: maybe there is a partition table that we do not support so we should warn the user anyway, but probably this would be too paranoid... I'll change that. Regards. Maciek Trela. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
