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removal of grpid option from ext4

DISCUSSION John Petersen 2 participants 2 messages Nov 17, 2010 – Nov 18, 2010

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The removal of this option puzzles me. It's extremely useful in an academic environment like ours, where different groups of researchers work in shared project spaces. I'd like to migrate our data partitions to ext4. If this option is going to disappear, I will have to seriously consider keeping current and new project spaces as ext3.

Thanks for considering my viewpoint,
--John

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John R. Petersen                    Department of Computer Science
UNIX Sysadmin&  NT abuse                   and Engineering
(206) 616-8507                  Box 352350, University of Washington
CSE 256                                   Seattle, WA 98195
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Quoted 6 lines · John Petersen

The removal of this option puzzles me. It's extremely useful in an academic environment like ours, where different groups of researchers work in shared project spaces. I'd like to migrate our data partitions to ext4. If this option is going to disappear, I will have to seriously consider keeping current and new project spaces as ext3.

So if people really insist on using it, then we'll keep it.

But one thing which I don't understand; why can't you just set the setgid bit on the shared spaces? This causes newly created files to have the same group id as the directory, and newly created subdirectories to have the set gid bit. Set the group id at the top directory of the project's directory hierarchy, and set the setgid bit, and all newly created files will inherit the group id of the directory --- and all newly created subdirectory will inherit the group id as well as the setgid bit.

This is the System V scheme, which is much more flexible than the BSD scheme, since you can set control whether you have the BSD behaviour or the original System V unix behaviour, which is to always use the primary group ID of the creator.

If you set the setgid bit on all directories (chmod -R g+s /mnt), then you'll effectively have the same behavior as the grpid mount option.

What we may do is add a pointer to a web page with this explanation so that people can understand there is a better alternative. Does this work for you?

Best regards,

- Ted