linux-ext4 - Re: [PATCH v2 2/4] ext4, jbd2: ensure panic when journal aborting with zero errno

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Message-ID: <20191203121046.GC8206@quack2.suse.cz>
Date:   Tue, 3 Dec 2019 13:10:46 +0100
From:   Jan Kara <jack@...e.cz>
To:     "zhangyi (F)" <yi.zhang@...wei.com>
Cc:     linux-ext4@...r.kernel.org, jack@...e.com, tytso@....edu,
        adilger.kernel@...ger.ca, liangyun2@...wei.com,
        luoshijie1@...wei.com
Subject: Re: [PATCH v2 2/4] ext4, jbd2: ensure panic when journal aborting
 with zero errno

On Tue 03-12-19 17:27:54, zhangyi (F) wrote:
> JBD2_REC_ERR flag used to indicate the errno has been updated when jbd2
> aborted, and then __ext4_abort() and ext4_handle_error() can invoke
> panic if ERRORS_PANIC is specified. But if the journal has been aborted
> with zero errno, jbd2_journal_abort() didn't set this flag so we can
> no longer panic. Fix this by rename JBD2_REC_ERR to JBD2_ABORT_DONE and
> set such flag even if there is no need to record errno in the jbd2 super
> block.
> 
> Fixes: 4327ba52afd03 ("ext4, jbd2: ensure entering into panic after recording an error in superblock")
> Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>

OK, makes sense. You can add:

Reviewed-by: Jan Kara <jack@...e.cz>

Although I'd note that after your patch 1, there is only a single place
that will call jbd2_journal_abort() with 0 errno - namely one place in
fs/jbd2/checkpoint.c and I think it would make sense for that call site to
just pass -EIO and we can completely drop the checks whether errno != 0.

								Honza

> ---
>  fs/ext4/super.c      |  4 ++--
>  fs/jbd2/journal.c    | 10 +++++-----
>  include/linux/jbd2.h |  3 ++-
>  3 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index dd654e53ba3d..25b0c883bd15 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -482,7 +482,7 @@ static void ext4_handle_error(struct super_block *sb)
>  		sb->s_flags |= SB_RDONLY;
>  	} else if (test_opt(sb, ERRORS_PANIC)) {
>  		if (EXT4_SB(sb)->s_journal &&
> -		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
> +		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT_DONE))
>  			return;
>  		panic("EXT4-fs (device %s): panic forced after error\n",
>  			sb->s_id);
> @@ -701,7 +701,7 @@ void __ext4_abort(struct super_block *sb, const char *function,
>  	}
>  	if (test_opt(sb, ERRORS_PANIC) && !system_going_down()) {
>  		if (EXT4_SB(sb)->s_journal &&
> -		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
> +		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_ABORT_DONE))
>  			return;
>  		panic("EXT4-fs panic from previous error\n");
>  	}
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 1c58859aa592..a78b07841080 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -2118,12 +2118,12 @@ static void __journal_abort_soft (journal_t *journal, int errno)
>  
>  	__jbd2_journal_abort_hard(journal);
>  
> -	if (errno) {
> +	if (errno)
>  		jbd2_journal_update_sb_errno(journal);
> -		write_lock(&journal->j_state_lock);
> -		journal->j_flags |= JBD2_REC_ERR;
> -		write_unlock(&journal->j_state_lock);
> -	}
> +
> +	write_lock(&journal->j_state_lock);
> +	journal->j_flags |= JBD2_ABORT_DONE;
> +	write_unlock(&journal->j_state_lock);
>  }
>  
>  /**
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index 603fbc4e2f70..71cab887fb98 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -1248,7 +1248,8 @@ JBD2_FEATURE_INCOMPAT_FUNCS(csum3,		CSUM_V3)
>  #define JBD2_ABORT_ON_SYNCDATA_ERR	0x040	/* Abort the journal on file
>  						 * data write error in ordered
>  						 * mode */
> -#define JBD2_REC_ERR	0x080	/* The errno in the sb has been recorded */
> +#define JBD2_ABORT_DONE	0x080	/* Abort done, the errno in the sb has been
> +				 * recorded if necessary */
>  
>  /*
>   * Function declarations for the journaling transaction and buffer
> -- 
> 2.17.2
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR