[Ocfs2-devel] [PATCH 2/6] ocfs2: Fix quota recovery failure on unmount

[Shichangkuo]

Hi Jan,
    This patch will cause kernel crashes while umounting ocfs2.
    After parsing the core file, I find the root reason is as follows:
    osb->recovery_map is freed when recovery thread exited, but following functions still access it by calling ocfs2_inode_lock.
    So, we should disable quotas between ocfs2_truncate_log_shutdown and ocfs2_recovery_exit.
    Am I right?

Thanks
Changkuo

>>>
> When filesystem is unmounted while there is still some recovery work going
> on, it can happen that quotas get disabled before quota recovery is complete
> resulting in failed quota recovery and inconsistent quota accounting. Move
> disabling of recovery in ocfs2_dismount_volume() before disabling of quotas
> to fix this race.
>
> Signed-off-by: Jan Kara <jack at suse.cz>
> ---
>  fs/ocfs2/super.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index
> ffa4952d432b..14c3d5ee6e24 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -1904,6 +1904,13 @@ static void ocfs2_dismount_volume(struct
> super_block *sb, int mnt_err)
>       /* Orphan scan should be stopped as early as possible */
>       ocfs2_orphan_scan_stop(osb);
>
> +     /*
> +      * This will disable recovery and flush any recovery work. This needs
> +      * to happen before disabling quotas as quota recovery needs quotas
> +      * enabled.
> +      */
> +     ocfs2_recovery_exit(osb);
> +
>       ocfs2_disable_quotas(osb);
>
>       /* All dquots should be freed by now */ @@ -1915,9 +1922,6 @@
> static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)
>
>       ocfs2_truncate_log_shutdown(osb);
>
> -     /* This will disable recovery and flush any recovery work. */
> -     ocfs2_recovery_exit(osb);
> -
>       ocfs2_journal_shutdown(osb);
>
>       ocfs2_sync_blockdev(sb);
> --
> 2.13.6

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