LFCS Question #359: Real Exam Question with Answer & Explanation

Question

You are certain that your kernel has been compiled with ACL support, however, when you try to set an ACL on a file, you get the following output: % setfacl m user:hugh:r afile.txt setfacl: afile.txt: Operation not supported What is the most likely reason for this problem?

Options

• AThere is an error in the command line parameters.
• BThere is no user on the system named hugh.
• CThe partition has not been mounted with the acl option.
• DThe file afile.txt doesn't exist.

Explanation

The "Operation not supported" error from setfacl indicates that the filesystem where the file resides has not been mounted with the acl option, despite kernel support.

Common mistakes.

• A. The command setfacl m user:hugh:r afile.txt appears syntactically correct for setting an ACL.
• B. If there were no user named hugh, setfacl would likely return an error about an invalid user, not "Operation not supported."
• D. If afile.txt didn't exist, setfacl would report "No such file or directory."

Concept tested. Filesystem ACL mount option

Reference. https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/storage_administration_guide/chap-acls

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