On Wed, Jan 26, 2011 at 8:55 AM, Paul Clements <paul.clements@xxxxxxxxxxx> wrote: > Attached is a modified patch, which does the extra necessary work > (bitmap_endwrite, md_write_end) on the bio before failing it. > > Does this look correct? It seems to work. Well, not quite...it's more complicated. From my reading of the code, it looks like behind writes and barrier retries just do not work correctly together. The issue is this: - With behind writes, we signal the master_bio complete as soon as all non-write-behind writes are complete. - With barrier retries, you don't know if you'll need to retry until you've completed all legs of the write (the last leg to complete might throw EOPNOTSUPP). So in the case where the master_bio has been completed, we still try to do a retry for the leg that failed the barrier (but it's really too late to retry). In any case, raid1d is touching master_bio (looking at bi_size and bio_cloning it) during the retry, which causes a panic if master_bio is already being reused by someone else. I can't think of a good way to do behind writes and barrier retries together. Seems we've got to disable behind writes for barriers, or we've got to disable barrier retries when doing behind writes... Any thoughts? -- Paul -- 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
