On Fri, Oct 13, 2017 at 10:47:29AM +0800, Zhilong Liu wrote: > > > On 10/13/2017 01:37 AM, Shaohua Li wrote: > > On Thu, Oct 12, 2017 at 04:30:51PM +0800, Zhilong Liu wrote: > > > Against the raids which chunk_size is meaningful, the component_size > > > must be >= chunk_size when require resize. If "new_size < chunk_size" > > > has required, the "mddev->pers->resize" will set sectors as '0', and > > > then the raids isn't meaningful any more due to mddev->dev_sectors is > > > '0'. > > > > > > Cc: Neil Brown <neilb@xxxxxxxx> > > > Signed-off-by: Zhilong Liu <zlliu@xxxxxxxx> > > Not sure about this, does size 0 disk really harm? > > > > From my site, I think changing the component size as '0' should be avoided. > When resize changing required and new_size < current_chunk_size, such as > raid5: > > raid5.c: raid5_resize() > ... > 7727 sectors &= ~((sector_t)conf->chunk_sectors - 1); > ... > > 'sectors' got '0'. > > then: > ... > 7743 mddev->dev_sectors = sectors; > ... > > the dev_sectors(the component size) got '0'. > same scenario happens in raid10. > > So, it's really not meaningful if changing the raid component_size to '0', > md > should give this scenario a test, otherwise, it's a trouble thing to restore > after > doing such invalid re-size. Yes, I understand how it could be 0. My question is what's wrong with a size-0 disk? For example, if you don't setup file for a loop block device, its size is 0. Thanks, Shaohua -- 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
