Illumos #3145, #3212

[zfs.git] / module / zfs / dbuf.c

diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index 99f728f..205abaa 100644 (file)
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -2189,7 +2189,24 @@ dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
                        dbuf_evict(db);
                } else {
                        VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
-                       if (!DBUF_IS_CACHEABLE(db))
+
+                       /*
+                        * A dbuf will be eligible for eviction if either the
+                        * 'primarycache' property is set or a duplicate
+                        * copy of this buffer is already cached in the arc.
+                        *
+                        * In the case of the 'primarycache' a buffer
+                        * is considered for eviction if it matches the
+                        * criteria set in the property.
+                        *
+                        * To decide if our buffer is considered a
+                        * duplicate, we must call into the arc to determine
+                        * if multiple buffers are referencing the same
+                        * block on-disk. If so, then we simply evict
+                        * ourselves.
+                        */
+                       if (!DBUF_IS_CACHEABLE(db) ||
+                           arc_buf_eviction_needed(db->db_buf))
                                dbuf_clear(db);
                        else
                                mutex_exit(&db->db_mtx);