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From: Frank van der Linden <fllinden@amazon.com>
To: Trond Myklebust <trondmy@hammerspace.com>
Cc: "tigran.mkrtchyan@desy.de" <tigran.mkrtchyan@desy.de>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
	"anna.schumaker@netapp.com" <anna.schumaker@netapp.com>
Subject: Re: [PATCH 03/13] NFSv4.2: query the server for extended attribute support
Date: Fri, 13 Mar 2020 17:55:29 +0000	[thread overview]
Message-ID: <20200313175529.GB31307@dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com> (raw)
In-Reply-To: <6792d6a6012a241b8bd1555eea8c592ff318a444.camel@hammerspace.com>

On Fri, Mar 13, 2020 at 01:50:38PM +0000, Trond Myklebust wrote:
> 'xattr_support' seems like a protocol hack to allow the client to
> determine whether or not the xattr operations are supported.
> 
> The reason why it is a hack is that 'supported_attrs' is also a per-
> filesystem attribute, and there is no value in advertising
> 'xattr_support' there unless your filesystem also supports xattrs.
> 
> IOW: the protocol forces you to do 2 round trips to the server in order
> to figure out something that really should be obvious with 1 round
> trip.

Right, that's the annoying part. I mean, theoretically, a server can
legally reject a GETATTR because you're asking for an unknown
attribute (e.g. xattr_support in this case). So then what I have
in my current patch (asking for both the supported_attrs and
xattr_support at once) might fail, and the mount would fail.

Which means I should split it up and have nfs4_do_fsinfo do
the 2nd part, just in case.

- Frank

  parent reply	other threads:[~2020-03-13 17:55 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 19:56 [PATCH 00/13] client side user xattr (RFC8276) support Frank van der Linden
2020-03-11 19:56 ` [PATCH 01/13] nfs,nfsd: NFSv4.2 extended attribute protocol definitions Frank van der Linden
2020-03-11 19:56 ` [PATCH 02/13] nfs: add client side only definitions for user xattrs Frank van der Linden
2020-03-11 19:56 ` [PATCH 03/13] NFSv4.2: query the server for extended attribute support Frank van der Linden
2020-03-12 16:15   ` Mkrtchyan, Tigran
2020-03-12 20:51     ` Frank van der Linden
2020-03-12 21:15       ` Frank van der Linden
2020-03-13 11:11         ` Mkrtchyan, Tigran
2020-03-13 13:50           ` Trond Myklebust
2020-03-13 14:19             ` Mkrtchyan, Tigran
2020-03-13 17:10               ` Trond Myklebust
2020-03-13 17:55             ` Frank van der Linden [this message]
2020-03-11 19:56 ` [PATCH 04/13] NFSv4.2: define limits and sizes for user xattr handling Frank van der Linden
2020-03-12 20:35   ` Schumaker, Anna
2020-03-11 19:56 ` [PATCH 05/13] NFSv4.2: add client side XDR handling for extended attributes Frank van der Linden
2020-03-12 20:49   ` Schumaker, Anna
2020-03-11 19:56 ` [PATCH 06/13] nfs: define nfs_access_get_cached function Frank van der Linden
2020-03-11 19:56 ` [PATCH 07/13] NFSv4.2: query the extended attribute access bits Frank van der Linden
2020-03-11 19:56 ` [PATCH 08/13] nfs: modify update_changeattr to deal with regular files Frank van der Linden
2020-03-11 19:56 ` [PATCH 09/13] nfs: define and use the NFS_INO_INVALID_XATTR flag Frank van der Linden
     [not found]   ` <20200324060215.GD11705@shao2-debian>
2020-03-24 16:21     ` [nfs] c5654df66d: stress-ng.msg.ops_per_sec 15.5% improvement Frank van der Linden
2020-03-11 19:56 ` [PATCH 10/13] nfs: make the buf_to_pages_noslab function available to the nfs code Frank van der Linden
2020-03-12 20:36   ` Schumaker, Anna
2020-03-11 19:56 ` [PATCH 11/13] NFSv4.2: add the extended attribute proc functions Frank van der Linden
2020-03-11 19:56 ` [PATCH 12/13] NFSv4.2: hook in the user extended attribute handlers Frank van der Linden
2020-03-11 19:56 ` [PATCH 13/13] NFSv4.2: add client side xattr caching Frank van der Linden
2020-03-12 20:39   ` Schumaker, Anna
2020-03-12 20:48   ` Schumaker, Anna
2020-03-12 19:06 ` [PATCH 00/13] client side user xattr (RFC8276) support Mkrtchyan, Tigran
2020-03-12 20:09 ` Anna Schumaker
2020-03-16 15:50   ` Frank van der Linden
2020-03-17 23:03   ` Frank van der Linden
2020-03-19 14:39     ` J. Bruce Fields

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