On 2017/11/8 21:30, Amir Goldstein Wrote: > On Wed, Nov 8, 2017 at 10:27 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: >> On Wed, Nov 8, 2017 at 8:59 AM, zhangyi (F) <yi.zhang@xxxxxxxxxx> wrote: >>> On 2017/11/8 5:38, Amir Goldstein Wrote: >>>> For old existing merge dirs whose "origin" xattr was not set at copy up >>>> time, we amend the situation on lookup. >>>> >>>> If no origin fh is stored in upper of a merge dir, store fh of upper most >>>> lower dir or 'null' fh if lower does not support file handles. We do this >>>> so we can filter out whiteouts in case lower dir is removed offline and >>>> then upper dir becomes a pure upper in a future mount. >>>> >>>> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> >>>> --- > [...] >> >>> At the same time, consider the opposite side, all directories move from a base filesystem which 'file >>> handle' supported to a not supported one. It will trigger NULL pointer crash in ovl_verify_origin_fh() >>> because fh is NULL but ofh was existed. Following change good ? >>> >>> - if (!ofh) >>> + if (!ofh || !fh) >>> return -ENODATA; >>> >> >> Thanks for pointing that out, but change is not good because it looses the >> information about finding a stored null_fh. >> If we do want to stick with ovl_null_fh trick, I could pass in &ovl_null_fh >> instead of NULL, in case of !ovl_can_decode_fh(origin->d_sb). >> This fixes the NULL pointer crash and I can remove this special case, > > Zhangyi, > > I pushed a fix rebased on overlayfs-next from today to > https://github.com/amir73il/linux/commits/ovl-whiteouts > > Tested it with xfs and with xfs without uuid (test patch). Hi Amir: Sorry for the late, I prefer to use ovl_null_fh too, this patch looks good to me. > I did not test the migration cases that you listed. As far as know, docker container migration will tar all things in upper to lower layer, may be I thought to much and we may no need to deal with this case now. Thanks, Yi. > Please review. > Thanks, > Amir. > -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
