Where are ACL entries stored?

[Shaun See]

Hey all...

I did some searching and found lots of good information about ACL's and HP/UX but cannot seem to put my finger on where the ACL entries are stored?

My guess is that they are in the inode table somewhere?

Why do I care? If I setup optional ACL entries for files in a MC/SG cluster will they move with the disk to the alternate node after a fail-over?

Thanx for any help...

Shaun

P.S. HP/UX 11.11 with Online JFS 3.3

[Jeff Schussele · Accepted solution]

Hi Shaun,

Yes, they're stored in the inode table entry for that file/dir & therefore would move with the LV/FS to the adoptive node.

Rgds,
Jeff

[Jeff Schussele]

And remember that you need JFS 3.3 ver 4 to support ACLs.
Here's a link to the JFS/OnLine JFS section of the SW Recovery Handbook

http://www2.itrc.hp.com/service/iv/docDisplay.do?docId=prodITRC/DE_SW_UX_swrec_EN_01_E/JFS.pdf

HTH,
Jeff

[Shaun See]

Thanks for the quick reply confirming my hunch and for the pointer to additnl info!

Shaun

[A. Clay Stephenson]

Well, to be precise, ACL's are not carried in the inode itself -- only the knowledge that there are ACL's (or not) associated with a particular file is carried in the inode itself. Having done a stat() to examine to see if the st_aclv bit is set do you then do a acl() system call specifying the pathname and specifying the ACL_CNT command. That let's you know how many ACL entries are associated with this file so that you can dynamically allocate a big enough array to hold the subsequent acl() system call specifying the ACL_GET command to populate the array. Having explained this in greater detail than you really want, the answer to your question is that, yes, the additional data is carried within the filesystem just not in the inode. The inode is simply not big enough and certainly not dynamic enough to handle the additional ACL metadata.

Man 2 stat and man 2 acl for more details.