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From: ebiederm@xmission.com (Eric W. Biederman)
To: Andreas Dilger <adilger@dilger.ca>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Christoph Hellwig <hch@infradead.org>,
	agruen@kernel.org, akpm@linux-foundation.org,
	viro@zeniv.linux.org.uk, dhowells@redhat.com,
	linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Serge E. Hallyn" <serge@hallyn.com>
Subject: Re: [PATCH -V7 21/26] richacl: xattr mapping functions
Date: Sat, 19 Nov 2011 01:35:11 -0800	[thread overview]
Message-ID: <m1lircxxo0.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <E394C0CC-6124-42FD-9962-A061DC4784E3@dilger.ca> (Andreas Dilger's message of "Thu, 20 Oct 2011 13:49:33 -0600")

Andreas Dilger <adilger@dilger.ca> writes:

> Just as an FYI, from back when we were trying to port Lustre to Solaris,
> Solaris itself uses a 64-bit "FUID" (32-bit UID + 32-bit namespace) to
> handle this.
>
> It has a table for arbitrary mapping of 128-bit Windows domains to a
> 32-bit FUID namespace (don't know much detail here, sorry), and it is
> (reasonably) expected that a single system will not be in more than
> 2^32 namespaces at once.  This keeps the datatypes sane (u64 or 2x u32)
> and doesn't put much complexity into the filesystem/kernel.  For most
> uses, the high 32-bit value is 0 (local Unix domain).

Interesting.  For now it looks to me like a fixed partitions of a uid
into a namespace identifier and a normal uid is a brittle path to walk.

I am looking at using something slightly more dynamic.  Here for your
user namespace you get this range of uids.  That nests better and
allows for more flexibility in the future.

I think I can mostly keep filesystems where they don't care.  With just
a few places changes where we take the filesystem uid and map it into
what we store in the vfs cache.  And when we read the uid value out
of the vfs cache and map it into the id value that the filesystem
needs.

Eric

  reply	other threads:[~2011-11-19  9:34 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-18 15:32 [PATCH -V7 00/26] New ACL format for better NFSv4 acl interoperability Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 01/26] vfs: Indicate that the permission functions take all the MAY_* flags Aneesh Kumar K.V
2011-10-18 15:32   ` Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 02/26] vfs: Add hex format for MAY_* flag values Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 03/26] vfs: Pass all mask flags down to iop->check_acl Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 04/26] vfs: Add a comment to inode_permission() Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 05/26] vfs: Add generic IS_ACL() test for acl support Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 06/26] vfs: Add IS_RICHACL() test for richacl support Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 07/26] vfs: Optimize out IS_RICHACL() if CONFIG_FS_RICHACL is not defined Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 08/26] vfs: Add new file and directory create permission flags Aneesh Kumar K.V
2011-10-19 16:42   ` J. Bruce Fields
2011-10-20  5:20     ` Aneesh Kumar K.V
2011-10-20  5:20       ` Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 09/26] vfs: Add delete child and delete self " Aneesh Kumar K.V
2011-10-19 22:09   ` J. Bruce Fields
2011-10-20  7:35     ` Aneesh Kumar K.V
2011-10-20  7:35       ` Aneesh Kumar K.V
2011-10-20  8:11       ` J. Bruce Fields
2011-10-18 15:32 ` [PATCH -V7 10/26] vfs: Make the inode passed to inode_change_ok non-const Aneesh Kumar K.V
2011-10-18 15:32   ` Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 11/26] vfs: Add permission flags for setting file attributes Aneesh Kumar K.V
2011-10-18 15:32   ` Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 12/26] vfs: Make acl_permission_check() work for richacls Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 13/26] richacl: In-memory representation and helper functions Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 14/26] richacl: Permission mapping functions Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 15/26] richacl: Compute maximum file masks from an acl Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 16/26] richacl: Update the file masks in chmod() Aneesh Kumar K.V
2011-10-18 15:32   ` Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 17/26] richacl: Permission check algorithm Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 18/26] richacl: Create-time inheritance Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 19/26] richacl: Check if an acl is equivalent to a file mode Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 20/26] richacl: Automatic Inheritance Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 21/26] richacl: xattr mapping functions Aneesh Kumar K.V
2011-10-18 15:32   ` Aneesh Kumar K.V
2011-10-19 22:20   ` J. Bruce Fields
2011-10-20  8:30     ` Aneesh Kumar K.V
2011-10-20  9:14       ` J. Bruce Fields
2011-10-20  9:19         ` Christoph Hellwig
2011-10-20 10:25           ` J. Bruce Fields
2011-10-20 10:25             ` J. Bruce Fields
2011-10-20 23:46             ` Andreas Gruenbacher
2011-10-20 23:46               ` Andreas Gruenbacher
2011-10-21  0:45               ` J. Bruce Fields
2011-10-21  9:40               ` Aneesh Kumar K.V
2011-10-21  9:40                 ` Aneesh Kumar K.V
2011-10-21 10:52                 ` Andreas Gruenbacher
2011-10-21 13:12                   ` Aneesh Kumar K.V
2011-10-21 23:58                     ` Andreas Gruenbacher
2011-10-20 11:02           ` Aneesh Kumar K.V
2011-10-20 11:02             ` Aneesh Kumar K.V
2011-10-20 17:49             ` J. Bruce Fields
2011-10-20 17:49               ` J. Bruce Fields
2011-10-20 19:49               ` Andreas Dilger
2011-11-19  9:35                 ` Eric W. Biederman [this message]
2011-11-19  9:28               ` Eric W. Biederman
2011-11-21 13:35                 ` J. Bruce Fields
2011-10-18 15:32 ` [PATCH -V7 22/26] vfs: Cache richacl in struct inode Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 23/26] vfs: Add richacl permission check Aneesh Kumar K.V
2011-10-18 15:32 ` [PATCH -V7 24/26] ext4: Use IS_POSIXACL() to check for POSIX ACL support Aneesh Kumar K.V
2011-10-18 15:33 ` [PATCH -V7 25/26] ext4: Implement rich acl for ext4 Aneesh Kumar K.V
2011-10-18 18:41   ` Andreas Dilger
2011-10-19  5:43     ` Aneesh Kumar K.V
2011-10-18 15:33 ` [PATCH -V7 26/26] ext4: Add Ext4 compat richacl feature flag Aneesh Kumar K.V
2011-10-18 16:17 ` [PATCH -V7 00/26] New ACL format for better NFSv4 acl interoperability Shea Levy
2011-10-19  5:54   ` Aneesh Kumar K.V
2011-10-19 22:21 ` J. Bruce Fields

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