[HDFS-7582] Enforce maximum number of ACL entries separately per access and default.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: namenode
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Release Note: Limit on Maximum number of ACL entries(32) will be enforced separately on access and default ACLs. So in total, max. 64 ACL entries can be present in a ACL spec.
• Assignee: Vinayakumar B
• Reporter: Vinayakumar B
• Created: 05/Jan/15 04:51
• Updated: 30/Aug/16 01:40
• Resolved: 21/Jul/15 09:50

Description

Current ACL limits are only on the total number of entries.

But there can be a situation where number of default entries for a directory will be more than half of the maximum entries, i.e. > 16.

In such case, under this parent directory only files can be created which will have ACLs inherited using parent's default entries.

But when directories are created, total number of entries will be more than the maximum allowed, because sub-directories copies both inherited ACLs as well as default entries.
Since currently there is no check while copying ACLs from default ACLs directory creation succeeds, but any modification (only permission on one entry also) on the same ACL will fail.

It would be better to enforce the maximum of 32 entries separately per access and default. This would be consistent with our observations testing ACLs on other file systems, such as XFS and ext3.