[Cluster-devel] [GFS2] gfs2: handle NULL rgd in set_rgrp_preferences
Bob Peterson
rpeterso at redhat.com
Tue May 5 16:43:29 UTC 2015
----- Original Message -----
> The function set_rgrp_preferences() does not handle the (rarely
> returned) NULL value from gfs2_rgrpd_get_next() and this patch
> fixes that.
>
> The fs image in question is only 150MB in size which allows for
> only 1 rgrp to be created. The in-memory rb tree has only 1 node
> and when gfs2_rgrpd_get_next() is called on this sole rgrp, it
> returns NULL. (Default behavior is to wrap around the rb tree and
> return the first node to give the illusion of a circular linked
> list. In the case of only 1 rgrp, we can't have
> gfs2_rgrpd_get_next() return the same rgrp (first, last, next all
> point to the same rgrp)... that would cause unintended consequences
> and infinite loops.)
>
> Resolves: rhbz#1211663
> Signed-off-by: Abhi Das <adas at redhat.com>
> ---
> fs/gfs2/rgrp.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index cb27065..900e515 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -978,10 +978,10 @@ static void set_rgrp_preferences(struct gfs2_sbd *sdp)
> rgd->rd_flags |= GFS2_RDF_PREFERRED;
> for (i = 0; i < sdp->sd_journals; i++) {
> rgd = gfs2_rgrpd_get_next(rgd);
> - if (rgd == first)
> + if (!rgd || rgd == first)
> break;
> }
> - } while (rgd != first);
> + } while (rgd && rgd != first);
> }
>
> /**
> --
> 1.8.1.4
>
>
Hi,
Thanks. Now in the for-next branch of the linux-gfs2 git tree.
FYI: I removed "Resolves:" for upstream.
Regards,
Bob Peterson
Red Hat File Systems
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