gfs2: read journal in large chunks

Use bios to read in the journal into the address space of the journal inode
(jd_inode), sequentially and in large chunks.  This is faster for locating the
journal head that the previous binary search approach.  When performing
recovery, we keep the journal in the address space until recovery is done,
which further speeds up things.

Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/super.c

@@ -45,6 +45,7 @@
 #include "util.h"
 #include "sys.h"
 #include "xattr.h"
+#include "lops.h"
 
 #define args_neq(a1, a2, x) ((a1)->ar_##x != (a2)->ar_##x)
 
@@ -425,7 +426,7 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
 
 	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
 
-	error = gfs2_find_jhead(sdp->sd_jdesc, &head);
+	error = gfs2_find_jhead(sdp->sd_jdesc, &head, false);
 	if (error)
 		goto fail;
 
@@ -680,7 +681,7 @@ static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp,
 		error = gfs2_jdesc_check(jd);
 		if (error)
 			break;
-		error = gfs2_find_jhead(jd, &lh);
+		error = gfs2_find_jhead(jd, &lh, false);
 		if (error)
 			break;
 		if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {