Commit 7a92deaa authored by Andreas Gruenbacher's avatar Andreas Gruenbacher
Browse files

gfs2: Fix atomic bug in gfs2_instantiate 



Replace test_bit() + set_bit() with test_and_set_bit() where we need an atomic
operation.  Use clear_and_wake_up_bit() instead of open coding it.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 9642c8c4

fs/gfs2/glock.c

+2 −6
Original line number Diff line number Diff line
@@ -496,7 +496,7 @@ int gfs2_instantiate(struct gfs2_holder *gh) 
	 * Since we unlock the lockref lock, we set a flag to indicate

	 * instantiate is in progress.

	 */

	if (test_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags)) {

	if (test_and_set_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags)) {

		wait_on_bit(&gl->gl_flags, GLF_INSTANTIATE_IN_PROG,

			    TASK_UNINTERRUPTIBLE);

		/*
@@ -509,14 +509,10 @@ int gfs2_instantiate(struct gfs2_holder *gh) 
		goto again;

	}



	set_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags);



	ret = glops->go_instantiate(gh);

	if (!ret)

		clear_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags);

	clear_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags);

	smp_mb__after_atomic();

	wake_up_bit(&gl->gl_flags, GLF_INSTANTIATE_IN_PROG);

	clear_and_wake_up_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags);

	return ret;

}