gfs2: Fix possible fs name overflows

This patch fixes three places in which temporary character buffers
could overflow due to the addition of the file system id from patch
3792ce97. Thanks to Dan Carpenter for pointing it out.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/glock.c

@@ -1788,8 +1788,8 @@ void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
 	unsigned long long dtime;
 	const struct gfs2_holder *gh;
 	char gflags_buf[32];
-	char fs_id_buf[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
+	char fs_id_buf[sizeof(sdp->sd_fsname) + 7];
 
 	memset(fs_id_buf, 0, sizeof(fs_id_buf));
 	if (fsid && sdp) /* safety precaution */

fs/gfs2/rgrp.c

@@ -2285,7 +2285,7 @@ void gfs2_rgrp_dump(struct seq_file *seq, struct gfs2_glock *gl,
 static void gfs2_rgrp_error(struct gfs2_rgrpd *rgd)
 {
 	struct gfs2_sbd *sdp = rgd->rd_sbd;
-	char fs_id_buf[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];
+	char fs_id_buf[sizeof(sdp->sd_fsname) + 7];
 
 	fs_warn(sdp, "rgrp %llu has an error, marking it readonly until umount\n",
 		(unsigned long long)rgd->rd_addr);

fs/gfs2/util.c

@@ -178,7 +178,7 @@ int gfs2_consist_rgrpd_i(struct gfs2_rgrpd *rgd, int cluster_wide,
 			 const char *function, char *file, unsigned int line)
 {
 	struct gfs2_sbd *sdp = rgd->rd_sbd;
-	char fs_id_buf[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];
+	char fs_id_buf[sizeof(sdp->sd_fsname) + 7];
 	int rv;
 
 	sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname);