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Commit 0a52aba7 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Bob Peterson
Browse files

gfs2: Switch to rhashtable_lookup_get_insert_fast 



Switch from rhashtable_lookup_insert_fast + rhashtable_lookup_fast to
rhashtable_lookup_get_insert_fast, which is cleaner and avoids an extra
rhashtable lookup.

At the same time, turn the retry loop in gfs2_glock_get into an infinite
loop.  The lookup or insert will eventually succeed, usually very fast,
but there is no reason to give up trying at a fixed number of
iterations.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
parent c3698987

fs/gfs2/glock.c

+21 −24
Original line number Diff line number Diff line
@@ -655,10 +655,10 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 
	struct lm_lockname name = { .ln_number = number,

				    .ln_type = glops->go_type,

				    .ln_sbd = sdp };

	struct gfs2_glock *gl, *tmp = NULL;

	struct gfs2_glock *gl, *tmp;

	struct address_space *mapping;

	struct kmem_cache *cachep;

	int ret, tries = 0;

	int ret = 0;



	rcu_read_lock();

	gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
@@ -723,35 +723,32 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 
	}



again:

	ret = rhashtable_lookup_insert_fast(&gl_hash_table, &gl->gl_node,

	rcu_read_lock();

	tmp = rhashtable_lookup_get_insert_fast(&gl_hash_table, &gl->gl_node,

						ht_parms);

	if (ret == 0) {

	if (!tmp) {

		*glp = gl;

		return 0;

		goto out;

	}



	if (ret == -EEXIST) {

		ret = 0;

		rcu_read_lock();

		tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);

		if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {

			if (++tries < 100) {

				rcu_read_unlock();

				cond_resched();

				goto again;

	if (IS_ERR(tmp)) {

		ret = PTR_ERR(tmp);

		goto out_free;

	}

			tmp = NULL;

			ret = -ENOMEM;

	if (lockref_get_not_dead(&tmp->gl_lockref)) {

		*glp = tmp;

		goto out_free;

	}

	rcu_read_unlock();

	} else {

		WARN_ON_ONCE(ret);

	}

	cond_resched();

	goto again;



out_free:

	kfree(gl->gl_lksb.sb_lvbptr);

	kmem_cache_free(cachep, gl);

	atomic_dec(&sdp->sd_glock_disposal);

	*glp = tmp;



out:

	rcu_read_unlock();

	return ret;

}