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Message-ID: <20200527205603.GB206249@google.com>
Date: Wed, 27 May 2020 13:56:03 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Chao Yu <yuchao0@...wei.com>
Cc: kernel-team@...roid.com, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v3] f2fs: avoid inifinite loop to wait for
flushing node pages at cp_error
On 05/27, Chao Yu wrote:
> On 2020/5/26 9:56, Jaegeuk Kim wrote:
> > On 05/26, Chao Yu wrote:
> >> On 2020/5/26 9:11, Chao Yu wrote:
> >>> On 2020/5/25 23:06, Jaegeuk Kim wrote:
> >>>> On 05/25, Chao Yu wrote:
> >>>>> On 2020/5/25 11:56, Jaegeuk Kim wrote:
> >>>>>> Shutdown test is somtimes hung, since it keeps trying to flush dirty node pages
>
> 71.07% 0.01% kworker/u256:1+ [kernel.kallsyms] [k] wb_writeback
> |
> --71.06%--wb_writeback
> |
> |--68.96%--__writeback_inodes_wb
> | |
> | --68.95%--writeback_sb_inodes
> | |
> | |--65.08%--__writeback_single_inode
> | | |
> | | --64.35%--do_writepages
> | | |
> | | |--59.83%--f2fs_write_node_pages
> | | | |
> | | | --59.74%--f2fs_sync_node_pages
> | | | |
> | | | |--27.91%--pagevec_lookup_range_tag
> | | | | |
> | | | | --27.90%--find_get_pages_range_tag
>
> Before umount, kworker will always hold one core, that looks not reasonable,
> to avoid that, could we just allow node write, since it's out-place-update,
> and cp is not allowed, we don't need to worry about its effect on data on
> previous checkpoint, and it can decrease memory footprint cost by node pages.
It can cause some roll-forward recovery?
>
> Thanks,
>
> >>>>>
> >>>>> IMO, for umount case, we should drop dirty reference and dirty pages on meta/data
> >>>>> pages like we change for node pages to avoid potential dead loop...
> >>>>
> >>>> I believe we're doing for them. :P
> >>>
> >>> Actually, I mean do we need to drop dirty meta/data pages explicitly as below:
> >>>
> >>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> >>> index 3dc3ac6fe143..4c08fd0a680a 100644
> >>> --- a/fs/f2fs/checkpoint.c
> >>> +++ b/fs/f2fs/checkpoint.c
> >>> @@ -299,8 +299,15 @@ static int __f2fs_write_meta_page(struct page *page,
> >>>
> >>> trace_f2fs_writepage(page, META);
> >>>
> >>> - if (unlikely(f2fs_cp_error(sbi)))
> >>> + if (unlikely(f2fs_cp_error(sbi))) {
> >>> + if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
> >>> + ClearPageUptodate(page);
> >>> + dec_page_count(sbi, F2FS_DIRTY_META);
> >>> + unlock_page(page);
> >>> + return 0;
> >>> + }
> >>> goto redirty_out;
> >>> + }
> >>> if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
> >>> goto redirty_out;
> >>> if (wbc->for_reclaim && page->index < GET_SUM_BLOCK(sbi, 0))
> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >>> index 48a622b95b76..94b342802513 100644
> >>> --- a/fs/f2fs/data.c
> >>> +++ b/fs/f2fs/data.c
> >>> @@ -2682,6 +2682,12 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
> >>>
> >>> /* we should bypass data pages to proceed the kworkder jobs */
> >>> if (unlikely(f2fs_cp_error(sbi))) {
> >>> + if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
> >>> + ClearPageUptodate(page);
> >>> + inode_dec_dirty_pages(inode);
> >>> + unlock_page(page);
> >>> + return 0;
> >>> + }
> >>
> >> Oh, I notice previously, we will drop non-directory inode's dirty pages directly,
> >> however, during umount, we'd better drop directory inode's dirty pages as well, right?
> >
> > Hmm, I remember I dropped them before. Need to double check.
> >
> >>
> >>> mapping_set_error(page->mapping, -EIO);
> >>> /*
> >>> * don't drop any dirty dentry pages for keeping lastest
> >>>
> >>>>
> >>>>>
> >>>>> Thanks,
> >>>>>
> >>>>>> in an inifinite loop. Let's drop dirty pages at umount in that case.
> >>>>>>
> >>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> >>>>>> ---
> >>>>>> v3:
> >>>>>> - fix wrong unlock
> >>>>>>
> >>>>>> v2:
> >>>>>> - fix typos
> >>>>>>
> >>>>>> fs/f2fs/node.c | 9 ++++++++-
> >>>>>> 1 file changed, 8 insertions(+), 1 deletion(-)
> >>>>>>
> >>>>>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> >>>>>> index e632de10aedab..e0bb0f7e0506e 100644
> >>>>>> --- a/fs/f2fs/node.c
> >>>>>> +++ b/fs/f2fs/node.c
> >>>>>> @@ -1520,8 +1520,15 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
> >>>>>>
> >>>>>> trace_f2fs_writepage(page, NODE);
> >>>>>>
> >>>>>> - if (unlikely(f2fs_cp_error(sbi)))
> >>>>>> + if (unlikely(f2fs_cp_error(sbi))) {
> >>>>>> + if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
> >>>>>> + ClearPageUptodate(page);
> >>>>>> + dec_page_count(sbi, F2FS_DIRTY_NODES);
> >>>>>> + unlock_page(page);
> >>>>>> + return 0;
> >>>>>> + }
> >>>>>> goto redirty_out;
> >>>>>> + }
> >>>>>>
> >>>>>> if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
> >>>>>> goto redirty_out;
> >>>>>>
> >>>> .
> >>>>
> >>>
> >>>
> >>> _______________________________________________
> >>> Linux-f2fs-devel mailing list
> >>> Linux-f2fs-devel@...ts.sourceforge.net
> >>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> >>> .
> >>>
> > .
> >
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