Re: [f2fs-dev] [PATCH 5/6] f2fs: implement iomap operations

[Chao Yu]

On 2021/12/3 5:28, Jaegeuk Kim wrote:
> On 12/02, Jaegeuk Kim wrote:
> > On 12/02, Eric Biggers wrote:
> > > On Thu, Dec 02, 2021 at 11:00:47AM -0800, Jaegeuk Kim wrote:
> > > > On 12/02, Jaegeuk Kim wrote:
> > > > > On 12/02, Eric Biggers wrote:
> > > > > > On Thu, Dec 02, 2021 at 10:04:11PM +0800, Chao Yu wrote:
> > > > > > > On 2021/12/2 12:15, Eric Biggers wrote:
> > > > > > > > On Thu, Dec 02, 2021 at 11:10:41AM +0800, Chao Yu wrote:
> > > > > > > > > Why not relocating this check before f2fs_map_blocks()?
> > > > > > >
> > > > > > > Wait, it supports DIO in multi-device image after commit 	71f2c8206202
> > > > > > > ("f2fs: multidevice: support direct IO"), how about
> > > > > > > checking with f2fs_allow_multi_device_dio()?
> > > > > > >
> > > > > > > Thanks,
> > > > > >
> > > > > > Okay, that was not the case when I sent this patch originally.  We'll need to
> > > > > > update this to support multiple devices.
> > > > >
> > > > > Chao/Eric, does this make sense?
> > > > >
> > > > > --- a/fs/f2fs/data.c
> > > > > +++ b/fs/f2fs/data.c
> > > > > @@ -4070,11 +4070,10 @@ static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> > > > >                  }
> > > > >                  if (WARN_ON_ONCE(!__is_valid_data_blkaddr(map.m_pblk)))
> > > > >                          return -EINVAL;
> > > > > -               iomap->addr = blks_to_bytes(inode, map.m_pblk);
> > > > >
> > > > > -               if (WARN_ON_ONCE(f2fs_is_multi_device(F2FS_I_SB(inode))))
> > > > > -                       return -EINVAL;
> > > > > -               iomap->bdev = inode->i_sb->s_bdev;
> > > > > +               iomap->bdev = map->m_multidev_dio ? map.m_bdev :
> > > >
> > > > correction:			map.m_multidev_dio
> > >
> > > I guess so, but why doesn't f2fs_map_blocks() just always set m_bdev to the
> > > correct block device?  What is the point of m_multidev_dio?
> >
> > It seems we can simply assign iomap->bdev = map.m_bdev, and remove
> > map->m_multidev_dio.
>
> Ok, it was used in previous get_block flow, but I think it'd be worth to keep it
> to show by f2fs_map_blocks tracepoint.

Yes, it was added for that.

Thanks,

> > > - Eric
> >
> >
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