Re: [PATCH] xfs: don't run inodegc flushes when inodegc is not active

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Aug 04, 2021 at 08:46:16PM +1000, Dave Chinner wrote:
> 
> From: Dave Chinner <dchinner@redhat.com>
> 
> A flush trigger on a frozen filesystem (e.g. from statfs)
> will run queued inactivations and assert fail like this:
> 
> XFS: Assertion failed: mp->m_super->s_writers.frozen < SB_FREEZE_FS, file: fs/xfs/xfs_icache.c, line: 1861
> 
> Bug exposed by xfs/011.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Odd that I didn't see any of these problems in my overnight tests,
but the reasoning looks solid.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_icache.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 92006260fe90..f772f2a67a8b 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -1893,8 +1893,8 @@ xfs_inodegc_worker(
>   * wait for the work to finish. Two pass - queue all the work first pass, wait
>   * for it in a second pass.
>   */
> -void
> -xfs_inodegc_flush(
> +static void
> +__xfs_inodegc_flush(
>  	struct xfs_mount	*mp)
>  {
>  	struct xfs_inodegc	*gc;
> @@ -1913,6 +1913,14 @@ xfs_inodegc_flush(
>  	}
>  }
>  
> +void
> +xfs_inodegc_flush(
> +	struct xfs_mount	*mp)
> +{
> +	if (xfs_is_inodegc_enabled(mp))
> +		__xfs_inodegc_flush(mp);
> +}
> +
>  /*
>   * Flush all the pending work and then disable the inode inactivation background
>   * workers and wait for them to stop.
> @@ -1927,7 +1935,7 @@ xfs_inodegc_stop(
>  	if (!xfs_clear_inodegc_enabled(mp))
>  		return;
>  
> -	xfs_inodegc_flush(mp);
> +	__xfs_inodegc_flush(mp);
>  
>  	for_each_online_cpu(cpu) {
>  		gc = per_cpu_ptr(mp->m_inodegc, cpu);