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Date:   Tue, 10 Jul 2018 10:51:43 -0600
From:   dann frazier <dann.frazier@canonical.com>
To:     "Theodore Y. Ts'o" <tytso@mit.edu>, linux-ext4@vger.kernel.org,
        linux-kernel@vger.kernel.org, yanaijie@huawei.com,
        colin.king@canonical.com, kamal.mostafa@canonical.com,
        ike.pan@canonical.com
Subject: Re: [Bisect] ext4_validate_inode_bitmap:98: comm stress-ng: Corrupt
 inode bitmap
Message-ID: <20180710165143.GA20459@xps13.dannf>
References: <20180706174324.GA3049@xps13.dannf>
 <20180707041018.GB3546@thunk.org>
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On Sat, Jul 07, 2018 at 12:10:18AM -0400, Theodore Y. Ts'o wrote:
> On Fri, Jul 06, 2018 at 11:43:24AM -0600, dann frazier wrote:
> > Hi,
> >   We're seeing a regression triggered by the stress-ng[*] "chdir" test
> > that I've bisected to:
> > 
> > 044e6e3d74a3 ext4: don't update checksum of new initialized bitmaps
> > 
> > So far we've only seen failures on servers based on HiSilicon's family
> > of ARM64 SoCs (D05/Hi1616 SoC, D06/Hi1620 SoC). On these systems it is
> > very reproducible.
> 
> Thanks for the report.  Can you verify whether or not this patch fixes
> things for you?

hey Ted,
  Sorry for the delayed response - was afk for a long weekend.
Your patch does seem to fix the issue for me - after applying the
patch, I was able to survive 20 iterations (and counting), where
previously it would always fail the first time.

However, I've received a conflicting report from a colleague who
appears to still be seeing errors. I'll get back to you ASAP once I am
able to (in-?)validate that observation.

  -dann

> 					- Ted
> 
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index da6c10c1e37a..1cfb74bc4dca 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -90,6 +90,8 @@ static int ext4_validate_inode_bitmap(struct super_block *sb,
>  		return -EFSCORRUPTED;
>  
>  	ext4_lock_group(sb, block_group);
> +	if (buffer_verified(bh))
> +		goto verified;
>  	blk = ext4_inode_bitmap(sb, desc);
>  	if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
>  					   EXT4_INODES_PER_GROUP(sb) / 8)) {
> @@ -101,6 +103,7 @@ static int ext4_validate_inode_bitmap(struct super_block *sb,
>  		return -EFSBADCRC;
>  	}
>  	set_buffer_verified(bh);
> +verified:
>  	ext4_unlock_group(sb, block_group);
>  	return 0;
>  }