From: "J. Bruce Fields" <bfields@fieldses.org>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: "linux-cifs@vger.kernel.org" <linux-cifs@vger.kernel.org>,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
Theodore Ts'o <tytso@mit.edu>,
Linux API <linux-api@vger.kernel.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
LKML <linux-kernel@vger.kernel.org>,
XFS Developers <xfs@oss.sgi.com>,
Christoph Hellwig <hch@infradead.org>,
Steve French <smfrench@gmail.com>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Jeff Layton <jlayton@poochiereds.net>,
linux-ext4 <linux-ext4@vger.kernel.org>,
Anna Schumaker <anna.schumaker@netapp.com>
Subject: Re: [PATCH v15 00/22] Richacls (Core and Ext4)
Date: Tue, 10 Nov 2015 14:17:45 -0500 [thread overview]
Message-ID: <20151110191745.GA19379@fieldses.org> (raw)
In-Reply-To: <CAHc6FU6aWsWO1SOSyNVnbObE0GoE4dr5a3WVTgvX4xn0wum1Fg@mail.gmail.com>
On Tue, Nov 10, 2015 at 06:58:19PM +0100, Andreas Gruenbacher wrote:
> On Tue, Nov 10, 2015 at 6:07 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> > On Tue, Nov 10, 2015 at 10:43:46AM -0600, Steve French wrote:
> >> I don't have strong disagreement with using pseudo-xattrs to
> >> store/retrieve ACLs (we already do this) but retrieving/setting an ACL
> >> all at once can be awkward when ACLs are quite large e.g. when it
> >> encodes to over 1MB
> >
> > At least in the NFS case, that's also a limitation of the protocol.
>
> I couldn't find a limit in the NFSv4 specification, but the client and
> server implementations both define arbitrary ACL size limits. In
> addition, the xattr syscalls allow attributes to be up to 64k long.
I don't recall 4.0 specifying any limit, 4.1 does include negotiation of
maximum rpc calls and replies, and that effectively limits ACL sizes
since they have to fit in a single rpc.
> The bigger problem would be incrementally setting ACLs. To prevent
> processes from racing with each other, we would need a locking
> mechanism. In addition, the memory overhead would be prohibitive and
> access decisions would become extremely slow; we would have to come up
> with mechanisms to avoid those problems.
Right. Anyway, not worth the trouble, I think.
(Though what might be worth thinking about at some point is just making
sure we fail in helpful ways.)
--b.
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next prev parent reply other threads:[~2015-11-10 19:17 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-09 11:08 [PATCH v15 00/22] Richacls (Core and Ext4) Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 04/22] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 05/22] vfs: Add permission flags for setting file attributes Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 06/22] richacl: In-memory representation and helper functions Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 07/22] richacl: Permission mapping functions Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 08/22] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 09/22] richacl: Permission check algorithm Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 10/22] posix_acl: Unexport acl_by_type and make it static Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 11/22] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 12/22] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 13/22] vfs: Cache richacl in struct inode Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 14/22] richacl: Update the file masks in chmod() Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 15/22] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 16/22] richacl: Create-time inheritance Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 17/22] richacl: Automatic Inheritance Andreas Gruenbacher
2015-11-09 11:08 ` [PATCH v15 18/22] richacl: xattr mapping functions Andreas Gruenbacher
2015-11-09 11:09 ` [PATCH v15 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher
2015-11-11 1:16 ` Andreas Gruenbacher
2015-11-09 11:09 ` [PATCH v15 20/22] vfs: Add richacl permission checking Andreas Gruenbacher
2015-11-09 11:09 ` [PATCH v15 21/22] ext4: Add richacl support Andreas Gruenbacher
2015-11-09 11:09 ` [PATCH v15 22/22] ext4: Add richacl feature flag Andreas Gruenbacher
2015-11-10 11:29 ` [PATCH v15 00/22] Richacls (Core and Ext4) Christoph Hellwig
2015-11-10 12:39 ` Andreas Gruenbacher
2015-11-10 16:43 ` Steve French
2015-11-10 17:07 ` J. Bruce Fields
2015-11-10 17:58 ` Andreas Gruenbacher
2015-11-10 19:17 ` J. Bruce Fields [this message]
2015-11-11 7:57 ` Christoph Hellwig
2015-11-11 13:59 ` Andreas Gruenbacher
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