Hi john, Thanks for your test. I am on a vacation until 3, January. I will investigate the issue when I am back to work.
Thanks, Changwei Sent from my iPhone > On 30 Dec 2017, at 5:17 AM, John Lightsey <j...@nixnuts.net> wrote: > >> On Thu, 2017-12-28 at 06:38 +0000, Changwei Ge wrote: >> Hi Alex, >> >>> On 2017/12/28 14:22, alex chen wrote: >>> We has doubled extent number in ocfs2_populate_write_desc(), so >>> here we don't need to double again. >> >> I think your comment here makes sense. >> I will remove the multiplier 2 in my next version of this patch. >> > > This may have made it function in testing where it should have failed. > > I backported this patch to Debian's 4.9.65 kernel today, removed the *2 > multiplier, and hit a related assertion failure in this codepath: > > ocfs2_mark_extent_written > ocfs2_change_extent_flag > ocfs2_split_extent > ocfs2_split_and_insert > ocfs2_grow_tree > ocfs2_add_branch > ocfs2_create_new_meta_bhs > ocfs2_claim_metadata > > The assertion failure in ocfs2_claim_metadata() was > > BUG_ON(ac->ac_bits_wanted < (ac->ac_bits_given + bits_wanted)); > > My guess is that meta_ac was allocated at the beginning of the write, > then the tree was truncated during the write, so the actual allocation > is requesting more than was originally reserved. > > It seems like the codepaths where meta_ac != NULL also need to know > about the list of extents available in et_dealloc. > > The Perl code I used to hit this bug is attached. > <directio.pl> > _______________________________________________ > Ocfs2-devel mailing list > Ocfs2-devel@oss.oracle.com > https://oss.oracle.com/mailman/listinfo/ocfs2-devel _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel
