Ocfs2 devel - Nov 2018 - [PATCH] ocfs2: clear journal dirty flag after shutdown journal

Dirty flag of the journal should be cleared at the last stage of umount,
if do it before jbd2_journal_destroy(), then some metadata in uncommitted
transaction could be lost due to io error, but as dirty flag of journal
was already cleared, we can't find that until run a full fsck. This may
cause system panic or other corruption.

Signed-off-by: Junxiao Bi <junxiao.bi at oracle.com>
---
 fs/ocfs2/journal.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index b63c97f4318e..25d678c92fbb 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1017,6 +1017,10 @@ void ocfs2_journal_shutdown(struct ocfs2_super *osb)
 			mlog_errno(status);
 	}
 
+	/* Shutdown the kernel journal system */
+	jbd2_journal_destroy(journal->j_journal);
+	journal->j_journal = NULL;
+
 	if (status == 0) {
 		/*
 		 * Do not toggle if flush was unsuccessful otherwise
@@ -1027,10 +1031,6 @@ void ocfs2_journal_shutdown(struct ocfs2_super *osb)
 			mlog_errno(status);
 	}
 
-	/* Shutdown the kernel journal system */
-	jbd2_journal_destroy(journal->j_journal);
-	journal->j_journal = NULL;
-
 	OCFS2_I(inode)->ip_open_count--;
 
 	/* unlock our journal */
-- 
2.17.1

Hi Junxiao,

I'm very interested in this bug, and it seems causing read-only if
involving metadata. Could you help show how to reproduce this problem?

Thanks,
Jun

On 2018/11/16 16:58, Junxiao Bi wrote:
> Dirty flag of the journal should be cleared at the last stage of umount,
> if do it before jbd2_journal_destroy(), then some metadata in uncommitted
> transaction could be lost due to io error, but as dirty flag of journal
> was already cleared, we can't find that until run a full fsck. This may
> cause system panic or other corruption.
> 
> Signed-off-by: Junxiao Bi <junxiao.bi at oracle.com>
> ---
>  fs/ocfs2/journal.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
> index b63c97f4318e..25d678c92fbb 100644
> --- a/fs/ocfs2/journal.c
> +++ b/fs/ocfs2/journal.c
> @@ -1017,6 +1017,10 @@ void ocfs2_journal_shutdown(struct ocfs2_super *osb)
>  			mlog_errno(status);
>  	}
>  
> +	/* Shutdown the kernel journal system */
> +	jbd2_journal_destroy(journal->j_journal);
> +	journal->j_journal = NULL;
> +
>  	if (status == 0) {
>  		/*
>  		 * Do not toggle if flush was unsuccessful otherwise
> @@ -1027,10 +1031,6 @@ void ocfs2_journal_shutdown(struct ocfs2_super *osb)
>  			mlog_errno(status);
>  	}
>  
> -	/* Shutdown the kernel journal system */
> -	jbd2_journal_destroy(journal->j_journal);
> -	journal->j_journal = NULL;
> -
>  	OCFS2_I(inode)->ip_open_count--;
>  
>  	/* unlock our journal */
>

On 2018/11/16 16:58, Junxiao Bi wrote:
> Dirty flag of the journal should be cleared at the last stage of umount,
> if do it before jbd2_journal_destroy(), then some metadata in uncommitted
> transaction could be lost due to io error, but as dirty flag of journal
> was already cleared, we can't find that until run a full fsck. This may
> cause system panic or other corruption.
> 
> Signed-off-by: Junxiao Bi <junxiao.bi at oracle.com>
> ---
>  fs/ocfs2/journal.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
> index b63c97f4318e..25d678c92fbb 100644
> --- a/fs/ocfs2/journal.c
> +++ b/fs/ocfs2/journal.c
> @@ -1017,6 +1017,10 @@ void ocfs2_journal_shutdown(struct ocfs2_super *osb)
>  			mlog_errno(status);
>  	}
>  
> +	/* Shutdown the kernel journal system */
> +	jbd2_journal_destroy(journal->j_journal);
> +	journal->j_journal = NULL;
> +
Hi Junxiao,

I feel this adjustment doesn't make any sense. When jbd2_journal_destroy()
is
done, it still call ocfs2_journal_toggle_dirty() to clean dirty flag. Am I
wrong or understand error ?

Thanks.
Yiwen.
>  	if (status == 0) {
>  		/*
>  		 * Do not toggle if flush was unsuccessful otherwise
> @@ -1027,10 +1031,6 @@ void ocfs2_journal_shutdown(struct ocfs2_super *osb)
>  			mlog_errno(status);
>  	}
>  
> -	/* Shutdown the kernel journal system */
> -	jbd2_journal_destroy(journal->j_journal);
> -	journal->j_journal = NULL;
> -
>  	OCFS2_I(inode)->ip_open_count--;
>  
>  	/* unlock our journal */
>