▁its ▁relative ▁simplicity ▁and ▁wider ▁testing ▁base . ▁ ▁ext 3 ▁adds ▁the ▁following ▁features ▁to ▁ext 2 : ▁ ▁A ▁journal ▁ ▁Online ▁file ▁system ▁growth ▁ ▁HT ree ▁indexing ▁for ▁larger ▁directories ▁ ▁Without ▁these ▁features , ▁any ▁ext 3 ▁file ▁system ▁is ▁also ▁a ▁valid ▁ext 2 ▁file ▁system . ▁This ▁situation ▁has ▁allowed ▁well - test ed ▁and ▁m ature ▁file ▁system ▁maintenance ▁util ities ▁for ▁maintain ing ▁and ▁repair ing ▁ext 2 ▁file ▁systems ▁to ▁also ▁be ▁used ▁with ▁ext 3 ▁without ▁major ▁changes . ▁The ▁ext 2 ▁and ▁ext 3 ▁file ▁systems ▁share ▁the ▁same ▁standard ▁set ▁of ▁util ities , ▁e 2 fs pro gs , ▁which ▁includes ▁an ▁fs ck ▁tool . ▁The ▁close ▁relationship ▁also ▁makes ▁conversion ▁between ▁the ▁two ▁file ▁systems ▁( both ▁forward ▁to ▁ext 3 ▁and ▁back ward ▁to ▁ext 2 ) ▁straightforward . ▁ ▁ext 3 ▁la cks ▁" mod ern " ▁filesystem ▁features , ▁such ▁as ▁dynamic ▁in ode ▁allocation ▁and ▁ext ents . ▁This ▁situation ▁might ▁sometimes ▁be ▁a ▁dis adv antage , ▁but ▁for ▁recover ability , ▁it ▁is ▁a ▁significant ▁advantage . ▁The ▁file ▁system ▁metadata ▁is ▁all ▁in ▁fixed , ▁well - known ▁locations , ▁and ▁data ▁structures ▁have ▁some ▁redund ancy . ▁In ▁significant ▁data ▁cor ruption , ▁ext 2 ▁or ▁ext 3 ▁may ▁be ▁recover able , ▁while ▁a ▁tree - based ▁file ▁system ▁may ▁not . ▁ ▁Size ▁limits ▁The ▁maximum ▁number ▁of ▁blocks ▁for ▁ext 3 ▁is ▁ 2 3 2