GFS2: Fix rgrp end rounding problem for bsize < page size

This patch fixes a bug introduced by commit 7005c3e4. That patch
tries to map a vm range for resource groups, but the calculation
breaks down when the block size is less than the page size.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>

fs/gfs2/rgrp.c

@@ -933,8 +933,9 @@ static int read_rindex_entry(struct gfs2_inode *ip)
 		goto fail;
 
 	rgd->rd_gl->gl_object = rgd;
-	rgd->rd_gl->gl_vm.start = rgd->rd_addr * bsize;
-	rgd->rd_gl->gl_vm.end = rgd->rd_gl->gl_vm.start + (rgd->rd_length * bsize) - 1;
+	rgd->rd_gl->gl_vm.start = (rgd->rd_addr * bsize) & PAGE_CACHE_MASK;
+	rgd->rd_gl->gl_vm.end = PAGE_CACHE_ALIGN((rgd->rd_addr +
+						  rgd->rd_length) * bsize) - 1;
 	rgd->rd_rgl = (struct gfs2_rgrp_lvb *)rgd->rd_gl->gl_lksb.sb_lvbptr;
 	rgd->rd_flags &= ~(GFS2_RDF_UPTODATE | GFS2_RDF_PREFERRED);
 	if (rgd->rd_data > sdp->sd_max_rg_data)