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: Andreas Gruenbacher <agruenba@redhat.com>
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 19f38ae..258d8aa 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -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;
}