Re: [PATCH 01/11] f2fs: add nobarrier mount option

[Jaegeuk Kim <jaegeuk@kernel.org>]

Hi Chao,

On Tue, Jul 29, 2014 at 07:28:16PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> > Sent: Saturday, July 26, 2014 6:47 AM
> > To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net
> > Cc: Jaegeuk Kim
> > Subject: [f2fs-dev] [PATCH 01/11] f2fs: add nobarrier mount option
> > 
> > This patch adds a mount option, nobarrier, in f2fs.
> > The assumption in here is that file system keeps the IO ordering, but
> > doesn't care about cache flushes inside the storages.
> 
> Looks good to me.
> But it's better to add some description in f2fs document.

Good catch. :)
I'll add that.
Thanks,

> 
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> 
> Reviewed-by: Chao Yu <chao2.yu@samsung.com>
> 
> > ---
> >  fs/f2fs/data.c    | 5 ++++-
> >  fs/f2fs/f2fs.h    | 1 +
> >  fs/f2fs/segment.c | 3 +++
> >  fs/f2fs/super.c   | 7 +++++++
> >  4 files changed, 15 insertions(+), 1 deletion(-)
> > 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index c77c667..482313d 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -139,7 +139,10 @@ void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
> >  	/* change META to META_FLUSH in the checkpoint procedure */
> >  	if (type >= META_FLUSH) {
> >  		io->fio.type = META_FLUSH;
> > -		io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
> > +		if (test_opt(sbi, NOBARRIER))
> > +			io->fio.rw = WRITE_FLUSH | REQ_META | REQ_PRIO;
> > +		else
> > +			io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
> >  	}
> >  	__submit_merged_bio(io);
> >  	up_write(&io->io_rwsem);
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 8f507d4..e999eec 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -41,6 +41,7 @@
> >  #define F2FS_MOUNT_INLINE_XATTR		0x00000080
> >  #define F2FS_MOUNT_INLINE_DATA		0x00000100
> >  #define F2FS_MOUNT_FLUSH_MERGE		0x00000200
> > +#define F2FS_MOUNT_NOBARRIER		0x00000400
> > 
> >  #define clear_opt(sbi, option)	(sbi->mount_opt.opt &= ~F2FS_MOUNT_##option)
> >  #define set_opt(sbi, option)	(sbi->mount_opt.opt |= F2FS_MOUNT_##option)
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 8a6e57d..9fce0f47 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -239,6 +239,9 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi)
> >  	struct flush_cmd_control *fcc = SM_I(sbi)->cmd_control_info;
> >  	struct flush_cmd cmd;
> > 
> > +	if (test_opt(sbi, NOBARRIER))
> > +		return 0;
> > +
> >  	if (!test_opt(sbi, FLUSH_MERGE))
> >  		return blkdev_issue_flush(sbi->sb->s_bdev, GFP_KERNEL, NULL);
> > 
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 34649aa..eec89a2 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -52,6 +52,7 @@ enum {
> >  	Opt_inline_xattr,
> >  	Opt_inline_data,
> >  	Opt_flush_merge,
> > +	Opt_nobarrier,
> >  	Opt_err,
> >  };
> > 
> > @@ -69,6 +70,7 @@ static match_table_t f2fs_tokens = {
> >  	{Opt_inline_xattr, "inline_xattr"},
> >  	{Opt_inline_data, "inline_data"},
> >  	{Opt_flush_merge, "flush_merge"},
> > +	{Opt_nobarrier, "nobarrier"},
> >  	{Opt_err, NULL},
> >  };
> > 
> > @@ -339,6 +341,9 @@ static int parse_options(struct super_block *sb, char *options)
> >  		case Opt_flush_merge:
> >  			set_opt(sbi, FLUSH_MERGE);
> >  			break;
> > +		case Opt_nobarrier:
> > +			set_opt(sbi, NOBARRIER);
> > +			break;
> >  		default:
> >  			f2fs_msg(sb, KERN_ERR,
> >  				"Unrecognized mount option \"%s\" or missing value",
> > @@ -544,6 +549,8 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> >  		seq_puts(seq, ",inline_data");
> >  	if (!f2fs_readonly(sbi->sb) && test_opt(sbi, FLUSH_MERGE))
> >  		seq_puts(seq, ",flush_merge");
> > +	if (!f2fs_readonly(sbi->sb) && test_opt(sbi, NOBARRIER))
> > +		seq_puts(seq, ",nobarrier");
> >  	seq_printf(seq, ",active_logs=%u", sbi->active_logs);
> > 
> >  	return 0;
> > --
> > 1.8.5.2 (Apple Git-48)
> > 
> > 
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