From: Miao Xie <miaox@cn.fujitsu.com>
Subject: Re: [PATCH v2 4/7] VFS: Rename and refactor writeback_inodes_sb_if_idle
Date: Tue, 13 Dec 2011 11:34:05 +0800
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References: <1323367477-21685-1-git-send-email-kamal@canonical.com> <1323367477-21685-5-git-send-email-kamal@canonical.com>
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Cc: Jan Kara <jack@suse.cz>, Alexander Viro <viro@zeniv.linux.org.uk>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Matthew Wilcox <matthew@wil.cx>,
	Randy Dunlap <rdunlap@xenotime.net>,
	Theodore Tso <tytso@mit.edu>, linux-doc@vger.kernel.org,
	linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, Surbhi Palande <csurbhi@gmail.com>,
	Valerie Aurora <val@vaaconsulting.com>,
	Christopher Chaltain <christopher.chaltain@canonical.com>,
	"Peter M. Petrakis" <peter.petrakis@canonical.com>,
	Mikulas Patocka <mpatocka@redhat.com>
To: Kamal Mostafa <kamal@canonical.com>
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On thu, 8 Dec 2011 10:04:34 -0800, Kamal Mostafa wrote:
>  /**
> - * writeback_inodes_sb_if_idle	-	start writeback if none underway
> + * try_to_writeback_inodes_sb_nr	-	start writeback if none underway
>   * @sb: the superblock
>   * @nr: the number of pages to write
>   *
>   * Invoke writeback_inodes_sb if no writeback is currently underway.
>   * Returns 1 if writeback was started, 0 if not.
>   */
> -int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
> +int try_to_writeback_inodes_sb_nr(struct super_block *sb,
>  				   unsigned long nr,
>  				   enum wb_reason reason)
>  {
>  	if (!writeback_in_progress(sb->s_bdi)) {
>  		down_read(&sb->s_umount);
> -		writeback_inodes_sb_nr(sb, nr, reason);
> +		if (nr == 0)
> +			writeback_inodes_sb(sb, reason);
> +		else
> +			writeback_inodes_sb_nr(sb, nr, reason);
>  		up_read(&sb->s_umount);
>  		return 1;
>  	} else
>  		return 0;

The comment said "Returns 1 if writeback was started", so if writeback_in_progress()
return true, I think this function also should return 1.

BTW: Does anyone know when this patchset will be merged into the main tree?

Thanks
Miao