Generic name to handle and open by handle syscalls [LWN.net]

From:		"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To:		hch@infradead.org, viro@zeniv.linux.org.uk, adilger@sun.com, corbet@lwn.net, neilb@suse.de, npiggin@kernel.dk, hooanon05@yahoo.co.jp, bfields@fieldses.org, miklos@szeredi.hu
Subject:		[PATCH -V21 00/12] Generic name to handle and open by handle syscalls
Date:		Tue, 5 Oct 2010 15:52:08 +0530
Message-ID:		<1286274140-26533-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Cc:		linux-fsdevel@vger.kernel.org, sfrench@us.ibm.com, philippe.deniel@CEA.FR, linux-kernel@vger.kernel.org
Archive-link:		Article, Thread

Hi,

The below set of patches implement open by handle support using exportfs
operations. This allows user space application to map a file name to file
handle and later open the file using handle. This should be usable
for userspace NFS [1] and 9P server [2]. XFS already support this with the ioctls
XFS_IOC_PATH_TO_HANDLE and XFS_IOC_OPEN_BY_HANDLE.

[1] http://nfs-ganesha.sourceforge.net/
[2] http://thread.gmane.org/gmane.comp.emulators.qemu/68992

git repo for the patchset at:
git://git.kernel.org/pub/scm/linux/kernel/git/kvaneesh/linux-open-handle.git open-by-handle

Test case can be found at
http://git.kernel.org/?p=fs/ext2/kvaneesh/handle-test.git
git://git.kernel.org/pub/scm/fs/ext2/kvaneesh/handle-test.git

Changes from V20:
a) Use better variable names
b) change handle_size type to __u32
c) max handle size is now nfsv4 handle size. Considering file system would
   want to support a handle that can fit into nfsv4 handle size limiting
   max handle size to 128 rather than 4096 is the right thing.
d) I didn't add Ceph changes in the series. I am expecting the changes
   will go via Ceph tree.

-aneesh