linux-kernel - RE: [PATCH 1/2] f2fs: reorganize __f2fs_add

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Message-id: <006501d0c5fb$f6e12dc0$e4a38940$@samsung.com>
Date:	Fri, 24 Jul 2015 18:31:16 +0800
From:	Chao Yu <chao2.yu@...sung.com>
To:	'Jaegeuk Kim' <jaegeuk@...nel.org>
Cc:	linux-f2fs-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: RE: [PATCH 1/2] f2fs: reorganize __f2fs_add_link

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@...nel.org]
> Sent: Friday, July 24, 2015 2:15 AM
> To: Chao Yu
> Cc: linux-f2fs-devel@...ts.sourceforge.net; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 1/2] f2fs: reorganize __f2fs_add_link
> 
> Hi Chao,
> 
> On Wed, Jul 22, 2015 at 06:21:52PM +0800, Chao Yu wrote:
> > Firstly, spliting init_inode_metadata into two parts as below since they
> > are relatively independent.
> > 1) init_inode_metadata: init datas belong to newly created inode;
> > 2) update_inode_metadata: update inode info for linking inode to new
> > dentry.
> >
> > Secondly, move init_inode_metadata to the front of __f2fs_add_link,
> > So the flow of __f2fs_add_link will be reorganized as:
> > 1) init inode meta data for new creatation;
> > 2) lookup dentry page and insert new directory entry in the page;
> > 3) update meta data of inode and parent.
> >
> > Signed-off-by: Chao Yu <chao2.yu@...sung.com>
> > ---
> >  fs/f2fs/dir.c    | 129 ++++++++++++++++++++++++++++++++-----------------------
> >  fs/f2fs/f2fs.h   |   4 +-
> >  fs/f2fs/inline.c |   2 +-
> >  3 files changed, 78 insertions(+), 57 deletions(-)
> >
> > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> > index a34ebd8..0ad9a1c 100644
> > --- a/fs/f2fs/dir.c
> > +++ b/fs/f2fs/dir.c
> > @@ -381,43 +381,68 @@ static int make_empty_dir(struct inode *inode,
> >  	return 0;
> >  }
> >
> > -struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
> > +int init_inode_metadata(struct inode *inode, struct inode *dir,
> >  			const struct qstr *name, struct page *dpage)
> >  {
> >  	struct page *page;
> >  	int err;
> >
> > -	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
> > -		page = new_inode_page(inode);
> > -		if (IS_ERR(page))
> > -			return page;
> > +	if (!is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE))
> > +		return 0;
> >
> > -		if (S_ISDIR(inode->i_mode)) {
> > -			err = make_empty_dir(inode, dir, page);
> > -			if (err)
> > -				goto error;
> > -		}
> > +	page = new_inode_page(inode);
> > +	if (IS_ERR(page))
> > +		return PTR_ERR(page);
> >
> > -		err = f2fs_init_acl(inode, dir, page, dpage);
> > +	if (S_ISDIR(inode->i_mode)) {
> > +		err = make_empty_dir(inode, dir, page);
> >  		if (err)
> > -			goto put_error;
> > +			goto error;
> > +	}
> >
> > -		err = f2fs_init_security(inode, dir, name, page);
> > +	err = f2fs_init_acl(inode, dir, page, dpage);
> > +	if (err)
> > +		goto put_error;
> > +
> > +	err = f2fs_init_security(inode, dir, name, page);
> > +	if (err)
> > +		goto put_error;
> > +
> > +	if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode)) {
> > +		err = f2fs_inherit_context(dir, inode, page);
> >  		if (err)
> >  			goto put_error;
> > +	}
> >
> > -		if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode)) {
> > -			err = f2fs_inherit_context(dir, inode, page);
> > -			if (err)
> > -				goto put_error;
> > -		}
> > -	} else {
> > -		page = get_node_page(F2FS_I_SB(dir), inode->i_ino);
> > -		if (IS_ERR(page))
> > -			return page;
> > +	if (f2fs_encrypted_inode(dir))
> > +		file_set_enc_name(inode);
> > +
> > +	update_inode(inode, page);
> > +	f2fs_put_page(page, 1);
> 
> We should not put the inode page here.
> Since checkpoint can be called and flush all the node pages with valid
> NAT entres. Once power-off happens after then, we can see unreachable NAT
> entries.

IMO, all callers of init_inode_metadata such as __f2fs_add_link/f2fs_do_tmpfile,
they are all protected well by cp_rwsem, so checkpoint & SPO will not easily
bother us.

1) Lately in __f2fs_add_link, ino of ipage will be inserted into directory entry
of parent's inode, this makes our nat entry of ipage reachable.
2) And also in __f2fs_tmpfile, ino will be added in orphan list, so all data
resource of the inode will be evicted after CP->SPO->RFR procedure.

Is there anything I missed?

Thanks,

> 
> Thanks,

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