Re: [PATCH v2 6/6] f2fs: give up CP_TRIMMED_FLAG if it drops discards

[Jaegeuk Kim]

On 10/24, Chao Yu wrote:
> Hi Jaegeuk,
> 
> On 2017/10/4 9:08, Chao Yu wrote:
> > From: Chao Yu <yuchao0@xxxxxxxxxx>
> > 
> > In ->umount, once we drop remained discard entries, we should not
> > set CP_TRIMMED_FLAG with another checkpoint.
> > 
> > Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> > ---
> > v2:
> > - rebase on last codes of Jaegeuk's dev-test branch.
> >  fs/f2fs/f2fs.h    |  2 +-
> >  fs/f2fs/segment.c | 15 +++++++++++----
> >  fs/f2fs/super.c   |  5 +++--
> >  3 files changed, 15 insertions(+), 7 deletions(-)
> > 
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index f274805e231d..c85f49c41003 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -2565,7 +2565,7 @@ void init_discard_policy(struct discard_policy *dpolicy, int discard_type,
> >  						unsigned int granularity);
> >  void refresh_sit_entry(struct f2fs_sb_info *sbi, block_t old, block_t new);
> >  void stop_discard_thread(struct f2fs_sb_info *sbi);
> > -void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
> > +bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
> >  void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc);
> >  void release_discard_addrs(struct f2fs_sb_info *sbi);
> >  int npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 4a108321233d..bfbcff8339c5 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1196,12 +1196,13 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
> >  	return issued;
> >  }
> >  
> > -static void __drop_discard_cmd(struct f2fs_sb_info *sbi)
> > +static bool __drop_discard_cmd(struct f2fs_sb_info *sbi)
> >  {
> >  	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> >  	struct list_head *pend_list;
> >  	struct discard_cmd *dc, *tmp;
> >  	int i;
> > +	bool dropped = false;
> >  
> >  	mutex_lock(&dcc->cmd_lock);
> >  	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {
> > @@ -1209,9 +1210,12 @@ static void __drop_discard_cmd(struct f2fs_sb_info *sbi)
> >  		list_for_each_entry_safe(dc, tmp, pend_list, list) {
> >  			f2fs_bug_on(sbi, dc->state != D_PREP);
> >  			__remove_discard_cmd(sbi, dc);
> > +			dropped = true;
> >  		}
> >  	}
> >  	mutex_unlock(&dcc->cmd_lock);
> > +
> > +	return dropped;
> >  }
> >  
> >  static void __wait_one_discard_bio(struct f2fs_sb_info *sbi,
> > @@ -1306,15 +1310,18 @@ void stop_discard_thread(struct f2fs_sb_info *sbi)
> >  }
> >  
> >  /* This comes from f2fs_put_super */
> > -void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
> > +bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
> >  {
> >  	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> >  	struct discard_policy dpolicy;
> > +	bool dropped;
> >  
> >  	init_discard_policy(&dpolicy, DPOLICY_UMOUNT, dcc->discard_granularity);
> >  	__issue_discard_cmd(sbi, &dpolicy);
> > -	__drop_discard_cmd(sbi);
> > +	dropped = __drop_discard_cmd(sbi);
> >  	__wait_all_discard_cmd(sbi, &dpolicy);
> > +
> > +	return dropped;
> >  }
> >  
> >  static int issue_discard_thread(void *data)
> > @@ -1659,7 +1666,7 @@ void init_discard_policy(struct discard_policy *dpolicy,
> >  		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
> >  		dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
> >  		dpolicy->io_aware_gran = MAX_PLIST_NUM;
> > -		dpolicy->io_aware = false;
> > +		dpolicy->io_aware = true;
> 
> I notice this change should not belong to this patch, could you please help to
> move this into "f2fs: split discard policy" in your branch?

Yup, done. Could you check it in dev-test?

Thanks,

> 
> Thanks,
> 
> >  	} else if (discard_type == DPOLICY_FSTRIM) {
> >  		dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
> >  		dpolicy->io_aware_gran = MAX_PLIST_NUM;
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index a13269d1a1f0..1d68c18a487b 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -807,6 +807,7 @@ static void f2fs_put_super(struct super_block *sb)
> >  {
> >  	struct f2fs_sb_info *sbi = F2FS_SB(sb);
> >  	int i;
> > +	bool dropped;
> >  
> >  	f2fs_quota_off_umount(sb);
> >  
> > @@ -827,9 +828,9 @@ static void f2fs_put_super(struct super_block *sb)
> >  	}
> >  
> >  	/* be sure to wait for any on-going discard commands */
> > -	f2fs_wait_discard_bios(sbi, true);
> > +	dropped = f2fs_wait_discard_bios(sbi);
> >  
> > -	if (f2fs_discard_en(sbi) && !sbi->discard_blks) {
> > +	if (f2fs_discard_en(sbi) && !sbi->discard_blks && !dropped) {
> >  		struct cp_control cpc = {
> >  			.reason = CP_UMOUNT | CP_TRIMMED,
> >  		};
> >