linux-kernel - Re: [f2fs-dev] [PATCH 2/3] f2fs: clear writeback when compression failed

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Message-ID: <ZhmgNBozIPL-WFZR@google.com>
Date: Fri, 12 Apr 2024 20:57:24 +0000
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Chao Yu <chao@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 2/3] f2fs: clear writeback when compression
 failed

On 04/11, Chao Yu wrote:
> On 2024/4/10 4:34, Jaegeuk Kim wrote:
> > Let's stop issuing compressed writes and clear their writeback flags.
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> > ---
> >   fs/f2fs/compress.c | 33 +++++++++++++++++++++++++++++++--
> >   1 file changed, 31 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> > index d67c471ab5df..3a8ecc6aee84 100644
> > --- a/fs/f2fs/compress.c
> > +++ b/fs/f2fs/compress.c
> > @@ -1031,6 +1031,25 @@ static void set_cluster_writeback(struct compress_ctx *cc)
> >   	}
> >   }
> > +static void cancel_cluster_writeback(struct compress_ctx *cc, int submitted)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < cc->cluster_size; i++) {
> > +		if (!cc->rpages[i])
> > +			continue;
> > +		if (i < submitted) {
> > +			if (i)
> > +				f2fs_wait_on_page_writeback(cc->rpages[i],
> > +						DATA, true, true);
> > +			inode_inc_dirty_pages(cc->inode);
> > +			lock_page(cc->rpages[i]);
> > +		}
> > +		clear_page_private_gcing(cc->rpages[i]);
> > +		end_page_writeback(cc->rpages[i]);
> > +	}
> > +}
> > +
> >   static void set_cluster_dirty(struct compress_ctx *cc)
> >   {
> >   	int i;
> > @@ -1232,7 +1251,6 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
> >   		.page = NULL,
> >   		.encrypted_page = NULL,
> >   		.compressed_page = NULL,
> > -		.submitted = 0,
> >   		.io_type = io_type,
> >   		.io_wbc = wbc,
> >   		.encrypted = fscrypt_inode_uses_fs_layer_crypto(cc->inode) ?
> > @@ -1358,7 +1376,15 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
> >   			fio.compressed_page = cc->cpages[i - 1];
> >   		cc->cpages[i - 1] = NULL;
> > +		fio.submitted = 0;
> >   		f2fs_outplace_write_data(&dn, &fio);
> > +		if (unlikely(!fio.submitted)) {
> > +			cancel_cluster_writeback(cc, i);
> > +
> > +			/* To call fscrypt_finalize_bounce_page */
> > +			i = cc->valid_nr_cpages;
> 
> *submitted = 0; ?

And, it seems this is not enough to address kernel hang on wait_on_writeback
while running fsstress + shutdown test. Stay tuned.

> 
> Thanks,
> 
> > +			goto out_destroy_crypt;
> > +		}
> >   		(*submitted)++;
> >   unlock_continue:
> >   		inode_dec_dirty_pages(cc->inode);
> > @@ -1392,8 +1418,11 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
> >   out_destroy_crypt:
> >   	page_array_free(cc->inode, cic->rpages, cc->cluster_size);
> > -	for (--i; i >= 0; i--)
> > +	for (--i; i >= 0; i--) {
> > +		if (!cc->cpages[i])
> > +			continue;
> >   		fscrypt_finalize_bounce_page(&cc->cpages[i]);
> > +	}
> >   out_put_cic:
> >   	kmem_cache_free(cic_entry_slab, cic);
> >   out_put_dnode: