Talk:Extended file attributes

BeOS

How come this page does not even mention BeOS, one of the largest and earliest massive user of xattrs ??? Need to fix this ASAP, unless someone else has the time... Mmu man (talk) 15:28, 23 February 2010 (UTC)

Good point. Can anyone help? (I've left a message on user talk:Mmu man.) CWC 21:58, 23 February 2010 (UTC)

I'll be looking into it when I have time. Mmu man (talk) 14:32, 3 March 2010 (UTC)

AmigaOS

AmigaOS supported a type of extended attributes via the optional .info "icon" files. It also supported a comment string per file with support from the file system (although this was not strictly speaking general-purpose extended attributes, only a single comment attribute). 66.11.179.30 (talk) 15:51, 21 July 2010 (UTC)

OpenBSD

There is mention of OpenBSD chflags(1), but this seems to be supported by all BSDs and to only allow changes of a flag of bit fields, internally using the chflags(2)/lchflags(2) syscalls (inherited from NetBSD, and formerly from 4.4BSD). I don't have access to an OpenBSD system at the moment, but does it really allow arbitrary user extended attributes using that facility? If not that's IMO something else than the general extended attributes this article seems to be about...66.11.179.30 (talk) 15:47, 21 July 2010 (UTC)

Yes, those are just the generic *BSD/Mac OS X "BSD flags". I've removed that section. Guy Harris (talk) 20:06, 17 January 2012 (UTC)

FreeBSD

Does ZFS on FreeBSD support extended attributes? The article currently states that "Since FreeBSD 8.0, extended attributes are also supported on ZFS filesystem. [citation needed]", but the current FreeBSD 10.2 ZFS man page states "The xattr property is currently not supported on FreeBSD.". I'm going to be bold and remove this statement. If anyone has a good pointer, it is appreciated if you could add it back to the main page. MacFreek (talk) 14:32, 7 November 2015 (UTC)

Good move. Poking around the FreeBSD website, I found that their extended attributes facility seems to use two fields in the on-disk UFS2 inode structure, di_extsize and di_extb, allowing up to two blocks of xattr data.[1] However, ZFS uses the same approach as Solaris and NFS4: each file and directory N can have a 'hidden' directory in which each file is an attribute of N, represented by a optional block address for that directory in their on-disk inodes. For FreeBSD to support xattrs in ZFS without changing the on-disk structures, they would need code to safely map Solaris-style on-disk attributes to/from BSD-style attributes. Which would be hard to design, harder to write and very bloody difficult to make robust.

Cheers, CWC 02:40, 8 November 2015 (UTC)

And yet it works just fine since... No idea, I've fixed a permissions bug there somewhere in 2008. So it's been available for about a decade now. Trasz (talk) 14:08, 29 June 2017 (UTC)

Linux - getfattr and lsattr

I think the Linux "lsattr" command cannot be actually used for displaying these "extended file attributes" (ie the name/value pairs); instead it shows the "file attributes on a Linux second extended file system" (ie. some special file-system attributes related to storage mode of a file). IIUC these are completely different file attributes. There's some explanation of this at http://c50k.com/acl.html .

I think the mention of lsattr should be removed here, and instead could be added in some other article (maybe related to Linux file systems?). — Preceding unsigned comment added by 82.83.219.157 (talk) 21:30, 6 December 2015 (UTC)

Metadata on Linux Suggestion

In the sentence ...

Support for the extended attribute concept from a POSIX.1e draft that had been withdrawn in 1997 was added to Linux around 2002

... there is a word missing after '1997'. Which word would that be?

Can someone who knows better than me add infos about simple to use Linux derivates which support this out of the box? And an example how to add such metadata? That would be a nice info to have here. Heronils (talk) 09:18, 28 October 2017 (UTC)