[Samba] acl_xattr vs acl_tdb

Stan Hoeppner stan at hardwarefreak.com
Fri Mar 26 22:01:43 MDT 2010

Volker Lendecke put forth on 3/26/2010 7:39 AM:
> On Fri, Mar 26, 2010 at 08:38:19AM -0400, simo wrote:
>>>> There's something I would really like to know! But somehow it seems to 
>>>> be a secret of the gods that us mere mortals are not allowed to penetrate...
>>> Please say if there is any size restriction for xattrs in
>>> XFS. Hopefully there is none, which would mean that you can
>>> fill the whole file system with a single security descriptor
>>> if you wish.
>> If I remember correctly XFS used to have a size limit of 64KiB per
>> xattr.
> Shall I call you god now? :-)

No me.  Err, wikipedia:

XFS provides multiple data streams for files through its implementation of
extended attributes. These allow the storage of a number of name/value pairs
attached to a file. Names are null-terminated printable character strings of
up to 256 bytes in length, while their associated values can contain up to
64 KB of binary data. They are further subdivided into two namespaces, root
 and user. Extended attributes stored in the root namespace can be modified
only by the superuser, while attributes in the user namespace can be
modified by any user with permission to write to the file. Extended
attributes can be attached to any kind of XFS inode, including symbolic
links, device nodes, directories, etc. The attr  program can be used to
manipulate extended attributes from the command line, and the xfsdump and
xfsrestore utilities are aware of them and will back up and restore their
contents. Most other backup systems are not aware of extended attributes.


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