linux-kernel - Re: [PATCH] f2fs: don't set FI_COMPRESS

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Date:   Mon, 12 Dec 2022 15:05:08 -0800
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     zhoudan <zhuqiandann@...il.com>
Cc:     chao@...nel.org, linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, zhoudan8@...omi.com
Subject: Re: [PATCH] f2fs: don't set FI_COMPRESS_RELEASED if file is not
 compressed

On 12/12, zhoudan wrote:
> Maybe I'm not describing it clearly enough, but I think there is 
> something wrong with the logic here.The 'f2fs_release_compress_blocks'
> method does not determine if the file is compressed, but simply adds 
> the FI_COMPRESS_RELEASED flag. 

I firstly lost your point since f2fs_release_compress_blocks() checked
f2fs_compressed_file().

> In particular, in the current Android system, when the application is 
> installed, the release interface is called by default to release the 
> storage marked as compressed,  without checking whether the file is 
> actually compressed. In this case, when compress_mode is set to user, 
> calling the compress interface returns ENVAL and the file cannot be 
> compressed.
> So I think the implementation of release needs to be modified, and 
> only set FI_COMPRESS_RELEASED when it's really compressed and the 
> storage is released.
> 
> On Fri, Dec 09, 2022 at 12:19:44PM -0800, Jaegeuk Kim wrote:
> > On 12/08, zhoudan8 wrote:
> > > In compress_mode=user, f2fs_release_compress_blocks()
> > >  does not verify whether it has been compressed and
> > >  sets FI_COMPRESS_RELEASED directly. which will lead to
> > > return -EINVAL after calling compress.
> > > To fix it,let's do not set FI_COMPRESS_RELEASED if file
> > > is not compressed.
> > 
> > Do you mean you want to avoid EINVAL on a file having FI_COMPRESS_RELEASED
> > with zero i_compr_blokcs?
> > 
> > I think the current logic is giving the error on a released file already.
> > 
> > > 
> > > Signed-off-by: zhoudan8 <zhoudan8@...omi.com>
> > > ---
> > >  fs/f2fs/file.c | 3 +--
> > >  1 file changed, 1 insertion(+), 2 deletions(-)
> > > 
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index 82cda1258227..f32910077df6 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -3451,14 +3451,13 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
> > >  	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
> > >  	if (ret)
> > >  		goto out;
> > > -
> > > -	set_inode_flag(inode, FI_COMPRESS_RELEASED);
> > >  	inode->i_ctime = current_time(inode);
> > >  	f2fs_mark_inode_dirty_sync(inode, true);
> > >  
> > >  	if (!atomic_read(&F2FS_I(inode)->i_compr_blocks))
> > >  		goto out;
> > >  
> > > +	set_inode_flag(inode, FI_COMPRESS_RELEASED);
> > >  	f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> > >  	filemap_invalidate_lock(inode->i_mapping);
> > >  
> > > -- 
> > > 2.38.1