[PATCH v3 2/2] hostfs: store permissions in extended attributes

[Marko Petrović]

Hello,

I have written the third version of the patch. Thank you for all of your
recommendations.

While writing the third patch version, I noticed that there was a
serious limitation of the code in second patch, namely the whole
xattrperm feature was available only and only as boot time flag so it
could not be used when hostfs was built as module since modules don't
have hostfs_args() function.

To overcome that issue, I have changed the content of
struct super_block -> s_fs_info to point to a struct hostfs_fs_info
containing the string that was previously there (to be used by old
functions) and the per-mountpoint use_xattr flag.
This allows easy extending of mount options in the future and thus
providing more flexibility to userspace to configure the filesystem.
For example, hostfs_attr, acl and noacl could be the mount options added
for POSIX ACLs and extended attributes in the future and if there is a
desire for that, append could become a mount option now too.

Regarding xattrperm as the kernel boot parameter, I left it available and
it defines the default behavior when mounting the filesystem (when
neither xattrperm nor noxattrperm is specified in mount options).

What do you think about this new change? Please, let me know if you have
any concerns so that I can address them.

Best regards,
Marko Petrović