linux-ext4 - Re: [PATCH -V2 3/5] ext4: Fix the race between read_block_bitmap and mark_diskspace

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Message-id: <492AF231.1070104@sun.com>
Date:	Mon, 24 Nov 2008 21:28:01 +0300
From:	Alex Zhuravlev <Alex.Zhuravlev@....COM>
To:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Cc:	Theodore Tso <tytso@....EDU>, cmm@...ibm.com, sandeen@...hat.com,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH -V2 3/5] ext4: Fix the race between read_block_bitmap and
 mark_diskspace_used

strange ... I'd expect the code to check "uptodate" once buffer is locked. you?

thanks, Alex

Aneesh Kumar K.V wrote:
> @@ -319,9 +319,11 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
>  			    block_group, bitmap_blk);
>  		return NULL;
>  	}
> -	if (bh_uptodate_or_lock(bh))
> +	if (buffer_uptodate(bh) &&
> +	    !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))
>  		return bh;
>  
> +	lock_buffer(bh);
>  	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
>  	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
>  		ext4_init_block_bitmap(sb, bh, block_group, desc);

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