linux-kernel - Re: [f2fs-dev] [PATCH v2] f2fs: fix quota_sync failure due to f2fs_lock

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Message-ID: <20200424033527.GA106894@google.com>
Date:   Thu, 23 Apr 2020 20:35:27 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <yuchao0@...wei.com>
Cc:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: fix quota_sync failure due to
 f2fs_lock_op

On 04/24, Chao Yu wrote:
> On 2020/4/24 3:49, Jaegeuk Kim wrote:
> > On 04/23, Chao Yu wrote:
> >> On 2020/4/17 5:39, Jaegeuk Kim wrote:
> >>> f2fs_quota_sync() uses f2fs_lock_op() before flushing dirty pages, but
> >>> f2fs_write_data_page() returns EAGAIN.
> >>> Likewise dentry blocks, we can just bypass getting the lock, since quota
> >>> blocks are also maintained by checkpoint.
> >>>
> >>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> >>> ---
> >>> v2:
> >>>  - fix multipage write case
> >>>
> >>>  fs/f2fs/compress.c | 2 +-
> >>>  fs/f2fs/data.c     | 4 ++--
> >>>  2 files changed, 3 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> >>> index df7b2d15eacde..faaa358289010 100644
> >>> --- a/fs/f2fs/compress.c
> >>> +++ b/fs/f2fs/compress.c
> >>> @@ -985,7 +985,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
> >>>  	loff_t psize;
> >>>  	int i, err;
> >>>  
> >>> -	if (!f2fs_trylock_op(sbi))
> >>> +	if (!IS_NOQUOTA(inode) && !f2fs_trylock_op(sbi))
> >>>  		return -EAGAIN;
> >>
> >> I encounter deadlock..
> >>
> >> Should call f2fs_unlock_op() for non-quota compressed inode later.
> > 
> > Could you elaborate a bit?
> 
> I meant we need to change as below, otherwise, cp_rwsem can be negative
> after f2fs_unlock_op if writebacked datas are belong to compressed quota
> file.

Ah, I see. Fixed.

Thanks,

> 
> >From 817dc629c47d3000c595640ecb3099b880519d47 Mon Sep 17 00:00:00 2001
> From: Jaegeuk Kim <jaegeuk@...nel.org>
> Date: Thu, 9 Apr 2020 10:25:21 -0700
> Subject: [PATCH] f2fs: fix quota_sync failure due to f2fs_lock_op
> 
> f2fs_quota_sync() uses f2fs_lock_op() before flushing dirty pages, but
> f2fs_write_data_page() returns EAGAIN.
> Likewise dentry blocks, we can just bypass getting the lock, since quota
> blocks are also maintained by checkpoint.
> 
> Reviewed-by: Chao Yu <yuchao0@...wei.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/compress.c | 8 +++++---
>  fs/f2fs/data.c     | 4 ++--
>  2 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index df7b2d15eacd..26b071afe48a 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -985,7 +985,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
>  	loff_t psize;
>  	int i, err;
> 
> -	if (!f2fs_trylock_op(sbi))
> +	if (!IS_NOQUOTA(inode) && !f2fs_trylock_op(sbi))
>  		return -EAGAIN;
> 
>  	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
> @@ -1092,7 +1092,8 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
>  		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
> 
>  	f2fs_put_dnode(&dn);
> -	f2fs_unlock_op(sbi);
> +	if (!IS_NOQUOTA(inode))
> +		f2fs_unlock_op(sbi);
> 
>  	spin_lock(&fi->i_size_lock);
>  	if (fi->last_disk_size < psize)
> @@ -1118,7 +1119,8 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
>  out_put_dnode:
>  	f2fs_put_dnode(&dn);
>  out_unlock_op:
> -	f2fs_unlock_op(sbi);
> +	if (!IS_NOQUOTA(inode))
> +		f2fs_unlock_op(sbi);
>  	return -EAGAIN;
>  }
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 8dd48c5b6c0d..dd439dbb134d 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2660,8 +2660,8 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
>  			f2fs_available_free_memory(sbi, BASE_CHECK))))
>  		goto redirty_out;
> 
> -	/* Dentry blocks are controlled by checkpoint */
> -	if (S_ISDIR(inode->i_mode)) {
> +	/* Dentry/quota blocks are controlled by checkpoint */
> +	if (S_ISDIR(inode->i_mode) || IS_NOQUOTA(inode)) {
>  		fio.need_lock = LOCK_DONE;
>  		err = f2fs_do_write_data_page(&fio);
>  		goto done;
> -- 
> 2.18.0.rc1
> 
> 
> 
> > 
> >>
> >> Thanks,
> >>
> >>>  
> >>>  	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >>> index accd28728642a..5c8d3823d7593 100644
> >>> --- a/fs/f2fs/data.c
> >>> +++ b/fs/f2fs/data.c
> >>> @@ -2656,8 +2656,8 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
> >>>  			f2fs_available_free_memory(sbi, BASE_CHECK))))
> >>>  		goto redirty_out;
> >>>  
> >>> -	/* Dentry blocks are controlled by checkpoint */
> >>> -	if (S_ISDIR(inode->i_mode)) {
> >>> +	/* Dentry/quota blocks are controlled by checkpoint */
> >>> +	if (S_ISDIR(inode->i_mode) || IS_NOQUOTA(inode)) {
> >>>  		fio.need_lock = LOCK_DONE;
> >>>  		err = f2fs_do_write_data_page(&fio);
> >>>  		goto done;
> >>>
> > .
> >