mkfs.jffs2 not compiling, which acl.h?

KaiGai Kohei kaigai at kaigai.gr.jp
Sat Dec 9 11:40:56 EST 2006


I'm sorry for delayed responding.

> Actually, I'm not entirely sure what this code is doing at all -- isn't
> it interpreting on-disk xattrs representing ACLs assuming that they're
> in the same format as ext3 uses? If you use mkfs.jffs2 on a big-endian
> system, actually reading _from_ a jffs2 filesystem, does it do the right
> thing? What about from other file systems?

Because the on-disk xattr representation which holds any ACLs is
interpreted into _common_ format in the kernel, the user space
application including mkfs.jffs2 does not need to be conscious
the differences between filesystems or endians.

See, fs/xattr_acl.c in the kernel.
Any filesystem (excluding xfs) calls posix_acl_to_xattr() to interpret
the in-kernel representation of ACLs before returning it into userspace.

The common format is defined as a leading 'posix_acl_xattr_header' and
an array of 'posix_acl_xattr_entry'. All of them are represented in
little-endian ordering.

Thus, we can assume the same format as ext3 (and any filesystem) uses.
Is it OK?

Thanks,
-- 
KaiGai Kohei <kaigai at kaigai.gr.jp>




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