Description: ext4: Fix ext4_empty_dir() for directories with holes
References:
 https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19037
 https://lore.kernel.org/stable/20191202170213.4761-2-jack@suse.cz/
Notes:
 carnil> commit fixes Fixes: 4e19d6b65fb4 ("ext4: allow directory
 carnil> holes") which is in 5.3-rc1 but was backported to various other
 carnil> stable trees in 5.2.4, 5.1.21, 4.19.62, 4.14.135 and 4.9.187
 carnil> already.
Bugs:
upstream: released (5.5-rc3) [64d4ce892383b2ad6d782e080d25502f91bf2a38]
4.19-upstream-stable: released (4.19.92) [1e62ac6b1307129c0f9ca68e9db4227239b4ab19]
4.9-upstream-stable: released (4.9.208) [dfcbd407f81e645601bccef8912af79b3d1ca87b]
3.16-upstream-stable: N/A "Vulnerability introduced later"
sid: released (5.4.8-1)
4.19-buster-security: released (4.19.98-1)
4.9-stretch-security: released (4.9.210-1)
3.16-jessie-security: N/A "Vulnerability introduced later"