From: Abhi Das Date: Tue, 5 May 2015 16:26:04 +0000 (-0500) Subject: gfs2: handle NULL rgd in set_rgrp_preferences X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=959b6717175713259664950f3bba2418b038f69a;p=deliverable%2Flinux.git gfs2: handle NULL rgd in set_rgrp_preferences 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.) Signed-off-by: Abhi Das Signed-off-by: Bob Peterson --- diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index cb270651c613..900e515bbdf6 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); } /**