On 2018年06月05日 22:07, David Sterba wrote: > On Tue, Jun 05, 2018 at 09:47:46PM +0800, Qu Wenruo wrote: >> >> >> On 2018年06月05日 21:42, David Sterba wrote: >>> On Tue, Jun 05, 2018 at 01:34:03PM +0800, Qu Wenruo wrote: >>>> Hi David, >>>> >>>> It would be pretty nice if we could get this fix (or previous RFC patch) >>>> to get into current release cycle. >>>> >>>> As it's a unrecoverable data corruption, it would be better to get it >>>> fixed as soon as possible. >>> >>> That we can do, I'm planning to send 2nd pull by the end of the next >>> week as there's at least one patch in the queue now. >>> >>> This patch seems to big, can you please prepare a minimal version? >> >> The previous version (a completely different direction though) is much >> smaller. >> https://patchwork.kernel.org/patch/10440541/ >> >> However personally speaking, I still prefer this one, as it's much simpler. > > As this will go to older stable kernels, I'd rather split that to more > patches where the first one is > > --- a/fs/btrfs/scrub.c > +++ b/fs/btrfs/scrub.c > @@ -2799,7 +2799,7 @@ static int scrub_extent(struct scrub_ctx *sctx, struct > map_lookup *map, > have_csum = scrub_find_csum(sctx, logical, csum); > if (have_csum == 0) > ++sctx->stat.no_csum; > - if (sctx->is_dev_replace && !have_csum) { > + if (0 && sctx->is_dev_replace && !have_csum) { > ret = copy_nocow_pages(sctx, logical, l, > mirror_num, > > physical_for_dev_replace); > --- > > and then the whole callchain of copy_nocow_pages continues.
Understood. I could go this method. However I'm a little concerned about such "if (0 &&" usage. Although with gcc 8.1 it works without any warning, it still looks pretty strange, as compiler could one day detect such dead branch and find copy_nocow_pages() is never used. Thanks, Qu
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