linux-ext4 - Re: [PATCH] ext4: don't manipulate recovery flag when freezing no-journal fs

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Message-ID: <55C3A332.30408@redhat.com>
Date:	Thu, 06 Aug 2015 11:10:58 -0700
From:	Eric Sandeen <sandeen@...hat.com>
To:	ext4 development <linux-ext4@...r.kernel.org>
CC:	Stu Mark <smark@...to.com>
Subject: Re: [PATCH] ext4: don't manipulate recovery flag when freezing no-journal
 fs

On 8/5/15 3:13 PM, Eric Sandeen wrote:
> At some point along this sequence of changes:
> 
> f6e63f9 ext4: fold ext4_nojournal_sops into ext4_sops
> bb04457 ext4: support freezing ext2 (nojournal) file systems
> 9ca9238 ext4: Use separate super_operations structure for no_journal filesystems
> 
> ext4 started setting needs_recovery on filesystems without journals
> when they are unfrozen.  This makes no sense, and in fact confuses
> blkid to the point where it doesn't recognize the filesystem at all.
> 
> (freeze ext2; unfreeze ext2; run blkid; see no output; run dumpe2fs,
> see needs_recovery set on fs w/ no journal).
> 
> To fix this, don't manipulate the INCOMPAT_RECOVER feature on
> filesystems without journals.

Ted, if this passes review you might cc: stable on the commit as well.

Thanks,
-Eric

> Reported-by: Stu Mark <smark@...to.com>
> Signed-off-by: Eric Sandeen <sandeen@...hat.com>
> ---
> 
> Note, is there a reason that in ext4_freeze, if journal_flush
> fails, we skip the ext4_commit_super call?  I didn't change that
> here, but it seems odd.
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 58987b5..e7b345d 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -4833,10 +4833,11 @@ static int ext4_freeze(struct super_block *sb)
>  		error = jbd2_journal_flush(journal);
>  		if (error < 0)
>  			goto out;
> +
> +		/* Journal blocked and flushed, clear needs_recovery flag. */
> +		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
>  	}
>  
> -	/* Journal blocked and flushed, clear needs_recovery flag. */
> -	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
>  	error = ext4_commit_super(sb, 1);
>  out:
>  	if (journal)
> @@ -4854,8 +4855,11 @@ static int ext4_unfreeze(struct super_block *sb)
>  	if (sb->s_flags & MS_RDONLY)
>  		return 0;
>  
> -	/* Reset the needs_recovery flag before the fs is unlocked. */
> -	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
> +	if (EXT4_SB(sb)->s_journal) {
> +		/* Reset the needs_recovery flag before the fs is unlocked. */
> +		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
> +	}
> +
>  	ext4_commit_super(sb, 1);
>  	return 0;
>  }
> 
> --
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