[LU-7473] Enlarge ACL entry limitation Created: 24/Nov/15  Updated: 27/Jan/21  Resolved: 15/Jan/18

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: Lustre 2.8.0
Fix Version/s: Lustre 2.10.0

Type: New Feature Priority: Critical
Reporter: Li Xi (Inactive) Assignee: nasf (Inactive)
Resolution: Fixed Votes: 0
Labels: None

Issue Links:
Related
is related to LU-9514 sanity test 51f times out due to out ... Resolved
is related to LU-10513 Prepare small buffer for ACL RPC reply Resolved
Rank (Obsolete): 9223372036854775807

 Description   

The current limitation of ACL entries is 32, which is not enough for some use cases. The limitation is inherited since Lustre-1.6 (or even earlier verion). Is there any special reason we keep this small limitation? The only reason I can think of, is to prevent space from exhausting before inodes exhausts on MDT. But, still 32 is too small, can we enlarge or even remove the limitation?



 Comments   
Comment by Andreas Dilger [ 24/Nov/15 ]

The reason that there is a limit on the ACLs is that the client needs to preallocate the reply buffer to receive the ACL data from the server, so it cannot be unlimited. The kernel limit in the past was also 32 entries, which the Lustre code also used.

It seems it would be possible to increase the ACL limit to 64 (each entry is only 8 bytes). Since the ACL entries are sharing the same space as the LOV layout there is an upper limit on how much space the two of them can use, so this shouldn't make the replies too large.

There will be some compatibility issues if this size is increased, if older and newer clients are mixed in the same cluster, and newer clients set a larger ACL that older clients cannot access. Besides this, I don't think there will be any protocol compatibility issues, since the ACL buffer size is described in the request and the reply, and older servers should be able to handle the larger ACL from newer clients.

Please ensure any patch for this is tested with both older and newer clients against older and newer servers. It would also be useful to enhance the conf-sanity test_32 cases to include ACLs, if that is not already the case today.

Comment by Gerrit Updater [ 26/Apr/16 ]

Fan Yong (fan.yong@intel.com) uploaded a new patch: http://review.whamcloud.com/19790
Subject: LU-7473 acl: increase ACL entries limitation
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 3d33ba9e5d402c48bc8b76b9d4427b391ee85f65

Comment by Gerrit Updater [ 16/May/17 ]

Oleg Drokin (oleg.drokin@intel.com) merged in patch https://review.whamcloud.com/19790/
Subject: LU-7473 acl: increase ACL entries limitation
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 64b2fad22a4eb4727315709e014d8f74c5a7f289

Comment by Peter Jones [ 16/May/17 ]

Landed for 2,10

Comment by Gerrit Updater [ 19/Jul/17 ]

Fan Yong (fan.yong@intel.com) uploaded a new patch: https://review.whamcloud.com/28116
Subject: LU-7473 acl: prepare small buffer for ACL in RPC reply
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 971dbecce884acb07baccc175ea1e26336fff11c

Comment by Andreas Dilger [ 11/Jan/18 ]

Reopen to track landing of last patch.

Comment by nasf (Inactive) [ 15/Jan/18 ]

The patch https://review.whamcloud.com/28116 will be landed via LU-10513.

Comment by Andreas Dilger [ 15/Jan/18 ]

Reopen to remove 2.11 fix version.

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