Commit 961ae1d8 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Bob Peterson

gfs2: Fix glock rhashtable rcu bug

Before commit 88ffbf3e "GFS2: Use resizable hash table for glocks",
glocks were freed via call_rcu to allow reading the glock hashtable
locklessly using rcu.  This was then changed to free glocks immediately,
which made reading the glock hashtable unsafe.  Bring back the original
code for freeing glocks via call_rcu.
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Cc: stable@vger.kernel.org # 4.3+
parent 9b51f044
...@@ -80,9 +80,9 @@ static struct rhashtable_params ht_parms = { ...@@ -80,9 +80,9 @@ static struct rhashtable_params ht_parms = {
static struct rhashtable gl_hash_table; static struct rhashtable gl_hash_table;
void gfs2_glock_free(struct gfs2_glock *gl) static void gfs2_glock_dealloc(struct rcu_head *rcu)
{ {
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
if (gl->gl_ops->go_flags & GLOF_ASPACE) { if (gl->gl_ops->go_flags & GLOF_ASPACE) {
kmem_cache_free(gfs2_glock_aspace_cachep, gl); kmem_cache_free(gfs2_glock_aspace_cachep, gl);
...@@ -90,6 +90,13 @@ void gfs2_glock_free(struct gfs2_glock *gl) ...@@ -90,6 +90,13 @@ void gfs2_glock_free(struct gfs2_glock *gl)
kfree(gl->gl_lksb.sb_lvbptr); kfree(gl->gl_lksb.sb_lvbptr);
kmem_cache_free(gfs2_glock_cachep, gl); kmem_cache_free(gfs2_glock_cachep, gl);
} }
}
void gfs2_glock_free(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
if (atomic_dec_and_test(&sdp->sd_glock_disposal)) if (atomic_dec_and_test(&sdp->sd_glock_disposal))
wake_up(&sdp->sd_glock_wait); wake_up(&sdp->sd_glock_wait);
} }
......
...@@ -373,6 +373,7 @@ struct gfs2_glock { ...@@ -373,6 +373,7 @@ struct gfs2_glock {
loff_t end; loff_t end;
} gl_vm; } gl_vm;
}; };
struct rcu_head gl_rcu;
struct rhash_head gl_node; struct rhash_head gl_node;
}; };
......
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