[Cluster-devel] [GFS2 PATCH 3/9] gfs2: Empty the ail for the glock when rgrps are invalidated

[Steven Whitehouse]

Hi,

On 13/02/2019 15:21, Bob Peterson wrote:
> Before this patch, function rgrp_go_inval would not invalidate the
> ail list, which meant that there might still be buffers outstanding
> on the ail that had revokes still pending. If the revokes had still
> not been written when the glock was given to another node, and that
> node (with outstanding revokes) died for some reason, the resulting
> journal replay would replay the un-revoked rgrps, thus wiping out
> changes made by the node who rightfully received the rgrp in EX.
> This caused metadata corruption.
>
> Signed-off-by: Bob Peterson <rpeterso at redhat.com>

rgrp_go_sync() has a call to gfs2_ail_empty_gl() so there should be no 
revokes to worry about when rgrp_go_inval is called, because everything 
should have already been written to the log & flushed. Has something 
gone wrong in the logic which somehow allows that step to be skipped in 
some cases?

Steve.

> ---
>   fs/gfs2/glops.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
> index 9c86c8004ba7..4b0e52bf5825 100644
> --- a/fs/gfs2/glops.c
> +++ b/fs/gfs2/glops.c
> @@ -166,6 +166,8 @@ static void rgrp_go_sync(struct gfs2_glock *gl)
>   	error = filemap_fdatawait_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
>   	mapping_set_error(mapping, error);
>   	gfs2_ail_empty_gl(gl);
> +	gfs2_assert_withdraw(gl->gl_name.ln_sbd,
> +			     gl->gl_name.ln_sbd->sd_log_error == 0);
>   
>   	spin_lock(&gl->gl_lockref.lock);
>   	rgd = gl->gl_object;
> @@ -196,6 +198,7 @@ static void rgrp_go_inval(struct gfs2_glock *gl, int flags)
>   	WARN_ON_ONCE(!(flags & DIO_METADATA));
>   	gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
>   	truncate_inode_pages_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
> +	gfs2_ail_empty_gl(gl);
>   
>   	if (rgd)
>   		rgd->rd_flags &= ~GFS2_RDF_UPTODATE;