On 2018/1/31 10:52, Jaegeuk Kim wrote: > On 01/31, Gaoxiang (OS) wrote: >> Hi Jaegeuk, >> >> On 2018/1/31 10:39, Jaegeuk Kim wrote: >>> On 01/31, Gaoxiang (OS) wrote: >>>> Hi Jaegeuk, >>>> >>>> On 2018/1/31 10:18, Jaegeuk Kim wrote: >>>>> On 01/26, Gaoxiang (OS) wrote: >>>>>> Hi Jaegeuk and Chao, >>>>>> >>>>>> On 2018/1/26 9:36, Chao Yu wrote: >>>>>>> On 2018/1/26 6:06, Jaegeuk Kim wrote: >>>>>>>> >>>>>>>> Then, we don't need to wait for this as well as wait_on_all_pages_writeback() >>>>>>>> in the early stage in do_checkpoint()? >>>>>>>> >>>>>>>> So, it seems like we can modify like below: >>>>>>>> >>>>>>>> --- >>>>>>>> 1. while (get_pages()) >>>>>>>> sync_meta_pages() >>>>>>>> 2. if (enabled_nat_bits()) >>>>>>>> while (get_pages()) >>>>>>>> sync_meta_pages() >>>>>>>> >>>>>>>> 3. wait_on_all_pages_writeback() >>>>>>>> -> remove >>>>>>> >>>>>>> Would meta area across two devices? if it would, we need to wait all meta >>>>>>> be persisted in second device before f2fs_flush_device_cache? >>>>>>> >>>>>>>> >>>>>>>> 4. f2fs_flush_device_cache() >>>>> >>>>> -> remove >>>>> >>>>>>>> >>>>>>>> 5. update_meta_page() <- for first cp_block >>>>>>>> >>>>>>>> 6. update_meta_page()... <- payload >>>>>>>> >>>>>>>> 7. orphan writes >>>>>>>> >>>>>>>> 8. node_summary writes >>>>>>>> >>>>>>>> 9. update_meta_page() <- for last cp_block >>>>>>>> -> remove >>>>>>> >>>>>> >>>>>> - /* writeout checkpoint block */ >>>>>> - update_meta_page(sbi, ckpt, start_blk); >>>>>> - >>>>>> - /* wait for previous submitted node/meta pages writeback */ >>>>>> - wait_on_all_pages_writeback(sbi); >>>>>> - >>>>>> - if (unlikely(f2fs_cp_error(sbi))) >>>>>> - return -EIO; >>>>>> - >>>>>> Could also be removed, too? >>>>>> >>>>>> filemap_fdatawait_range(NODE_MAPPING(sbi), 0, LLONG_MAX); >>>>>> filemap_fdatawait_range(META_MAPPING(sbi), 0, LLONG_MAX); >>>>> >>>>> -> remove >>>>> >>>>> Hmm, think so. >>>>> >>>>>> >>>>>> >>>>>>> 9.1 sync_meta_pages(META) to make sure all meta IOs are issued. >>>>>>> >>>>>> >>>>>> If I understand correctly, I have the same questions with Chao. >>>>>> It seems that META doesn't have another flush mechanism (eg. flush >>>>>> thread) other than sync_meta_pages? >>>>> >>>>> 9.2 f2fs_flush_device_cache(), if we have multiple devices. >>>>> >>>>>> >>>>>>>> >>>>>>>> 10. wait_on_all_pages_writeback() >>>>> >>>>> 10.1. (f2fs_cp_error()) >>>>> return -EIO; >>>>> >>>>>>>> >>>>>>>> ---- >>>>>>>> Add) 11. commit_checkpoint() >>>>>>>> - update_meta_page() <- for last cp_block >>>>>>>> - sync_meta_pages(META_FLUSH) >>>>>>>> >>>>>>>> We don't need to wait for page_writeback any more. >>>>>>>> >>>>>> >>>>>> >>>>>> Apart from that, I think we should "wait_on_all_pages_writeback(sbi);" >>>>>> after META_FLUSH in case for pulluting the next checkpoint when the last >>>>>> cp block is failed to write with FUA? >>>>> >>>>> Next cp block won't be written by 10.1. >>>>> >>>> >>>> I think that 10.1 ensures the cp pack before the last cp_block was done. >>>> However, what if the last cp block writes fail later without FUA? >>> >>> Without FUA? The last cp_block is written by FUA, no? >> >> quote " >> Apart from that, I think we should "wait_on_all_pages_writeback(sbi);" >> after META_FLUSH in case for pulluting the next checkpoint when the last >> cp block is failed to write with FUA? >> " >> >> what I meant is that the last cp_block should be written by FUA. >> we need to use META_FLUSH to write last cp_block, right? :) > > Add) 11. commit_checkpoint() > - update_meta_page() <- for last cp_block > - sync_meta_pages(META_FLUSH) > > What do you mean? I added META_FLUSH. > > 9.1 sync_meta_pages(META); > -> 10. wait_on_all_pages_writeback(); > -> 11. sync_meta_pages(META_FLUSH); > > -> 9.1 sync_meta_pages(META); > -> 10. wait_on_all_pages_writeback(); > -> 10.1 f2fs_cp_error() -> return -EIO; > What I mean is should we need to ensure FUA writing to medium (using the last "wait_on_all_pages_writeback(sbi)") and then unblock_operation ,quit write_checkpoint, go on fs operations 11. commit_checkpoint() - update_meta_page() <- for last cp_block - sync_meta_pages(META_FLUSH) *12. wait_on_all_pages_writeback() * Sorry about my expression is not clear. Thanks, >> >> Thanks, >> >>> >>>> Should we need to ensure the last cp block going into device medium >>>> rather than device cache before switching to go into the next checkpoint >>>> (I mean we need to ensure writing to medium and then unblock_operation >>>> and quit write_checkpoint and go on fs operations)? >>>> >>>> Other parts seems OK for me :), I will sort out and resent a new patch. >>>> >>>> Thanks, >>>> >>>>>> >>>>>> >>>>>> Thanks all, >>>>>> >>>>>>>>> >>>>>>>>> @@ -1313,10 +1337,15 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) >>>>>>>>> sbi->last_valid_block_count = sbi->total_valid_block_count; >>>>>>>>> percpu_counter_set(&sbi->alloc_valid_block_count, 0); >>>>>>>>> >>>>>>>>> - /* Here, we only have one bio having CP pack */ >>>>>>>>> - sync_meta_pages(sbi, META_FLUSH, LONG_MAX, FS_CP_META_IO); >>>>>>>>> + /* Here, we have one bio having CP pack except cp pack 2 page */ >>>>>>>>> + sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO); >>>>>>>>> >>>>>>>>> /* wait for previous submitted meta pages writeback */ >>>>>>>>> + if (!test_opt(sbi, NOBARRIER)) >>>>>>>> >>>>>>>> The above has nothing to do with this patch. >>>>>>> >>>>>>> We only need to use wait_on_all_pages_writeback to keep writeback order of >>>>>>> previous metadata and last cp pack metadata if barrier is on? >>>>>>> >>>>>>> Thanks, >>>>>>> >>>>>>>> >>>>>>>>> + wait_on_all_pages_writeback(sbi); >>>>>>>>> + >>>>>>>>> + /* barrier and flush checkpoint cp pack 2 page */ >>>>>>>>> + commit_checkpoint(sbi, ckpt, start_blk); >>>>>>>>> wait_on_all_pages_writeback(sbi); >>>>>>>>> >>>>>>>>> release_ino_entry(sbi, false); >>>>>>>>> -- >>>>>>>>> 2.1.4 >>>>>>>> >>>>>>>> . >>>>>>>> >>>>>>>
