Re: [PATCH] erofs-utils: do not check ->idata_size for compressed files in erofs_prepare_inode_buffer()

[Yue Hu <zbestahu@gmail.com>]

On Thu, 17 Jun 2021 17:04:29 +0800
Gao Xiang <hsiangkao@linux.alibaba.com> wrote:

> Hi Yue,
> 
> On Thu, Jun 17, 2021 at 04:29:54PM +0800, Yue Hu wrote:
> > From: Yue Hu <huyue2@yulong.com>
> > 
> > erofs_write_compressed_file() will always set inode->idata_size = 0
> > if succeed, that means no tail-end data for compressed files. So, no
> > need to call erofs_prepare_tail_block() which is used to handle
> > tail-end data for that case. Just skip it.  
> 
> Thanks for the patch, due to somewhat long time so I don't quite
> remember the exact logic here now...
> 
> Yet from the description before, it's not strictly correct
> since my original intention would be to support tail-packing
> inline compressed data which is similar to uncompressed case
> to decrease tail extent I/O and save more space.

nice.

> 
> BTW, if you have some interest, would you like to implement it? :)

I don't know if i can finish it. But i would like to have a try :)

Thanks.

> 
> Thanks,
> Gao Xiang
> 
> > 
> > Also, correct 'a inode' -> 'an inode'.
> > 
> > Signed-off-by: Yue Hu <huyue2@yulong.com>
> > ---
> >  lib/inode.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/inode.c b/lib/inode.c
> > index b6108db..b5f66de 100644
> > --- a/lib/inode.c
> > +++ b/lib/inode.c
> > @@ -111,7 +111,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> >  	return d;
> >  }
> >  
> > -/* allocate main data for a inode */
> > +/* allocate main data for an inode */
> >  static int __allocate_inode_bh_data(struct erofs_inode *inode,
> >  				    unsigned long nblocks)
> >  {
> > @@ -572,11 +572,11 @@ static int erofs_prepare_inode_buffer(struct erofs_inode *inode)
> >  		int ret;
> >  
> >  		inode->datalayout = EROFS_INODE_FLAT_PLAIN;
> > -noinline:
> >  		/* expend an extra block for tail-end data */
> >  		ret = erofs_prepare_tail_block(inode);
> >  		if (ret)
> >  			return ret;
> > +noinline:
> >  		bh = erofs_balloc(INODE, inodesize, 0, 0);
> >  		if (IS_ERR(bh))
> >  			return PTR_ERR(bh);
> > -- 
> > 1.9.1