Date: Sat, 23 Nov 2013 17:53:38 -0500 (EST) From: Rick Macklem <rmacklem@uoguelph.ca> To: Pedro Giffuni <pfg@FreeBSD.org> Cc: Freebsd hackers list <freebsd-hackers@freebsd.org>, Richard Yao <ryao@gentoo.org>, Cedric Blancher <cedric.blancher@gmail.com> Subject: Re: O_XATTR support in FreeBSD? Message-ID: <820263347.19772534.1385247218007.JavaMail.root@uoguelph.ca> In-Reply-To: <5290B60D.2050006@FreeBSD.org>
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Pedro Giffuni wrote: > On 23.11.2013 02:13, Cedric Blancher wrote: > > On 22 November 2013 20:55, Pedro Giffuni <pfg@freebsd.org> wrote: > >> Well ... > >> > >> According to: > >> > >> https://wiki.freebsd.org/ZFS > >> > >> We do support Extended Attributes on ZFS but they differ from the > >> ones in > >> Solaris (and Linux). > > Well, we need the one specified in the NFSv4 standard. The Linux > > extended attributes are pretty much useless because they are size > > restricted (typical attribute size here is in the GB range, and for > > example NIH and CERN have even much bigger sizes), can't be > > accessed > > like normal files and are incompatible to Window's Alternate > > Streams. > > > > Ced > > I was unaware of a standard for EA beyond the old posix draft. > The reason for Extended Attributes is supporting ACL and we support > both > the draft posix and the NFS/win style ACLs. > Interestingly, FreeBSD has a VOP_OPENEXTATTR() but no syscall that uses it nor support for it in ZFS. (I'm just guessing it was intended for an openat(2) syscall at some time?) Btw Cedric, if you had mentioned "subfiles" or "fork files" in your subject line, you might have gotten a better answer. I, for one, didn't know what O_XATTR is. I also always get confused w.r.t. what to call these beasts. (NFSv4 calls the named attributes.) Btw, apps can use extended attributes (the limited sized atomically stored/read kind). They aren't just for storing ACLs. > Not sure about the status of NFSv4. The guys in the posix-1e list > should > know better. > The NFSv4 implementation in FreeBSD does not support it, although adding it wouldn't be hard if someone figures out how to do the syscall and adds support for the VOP()s in ZFS. (I'm not volunteering to do the latter. I have plenty of other stuff on my to-do list;-) rick > regards, > > Pedro. > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to > "freebsd-hackers-unsubscribe@freebsd.org" >
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