linux-nfs.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH Version 2 0/1] NFSv4.1 Fix umount when filelayout DS is also the MDS
@ 2012-06-14 16:12 andros
  2012-06-14 16:12 ` [PATCH Version 2 1/1] " andros
  0 siblings, 1 reply; 5+ messages in thread
From: andros @ 2012-06-14 16:12 UTC (permalink / raw)
  To: trond.myklebust; +Cc: linux-nfs, Andy Adamson

From: Andy Adamson <andros@netapp.com>

Version 2: Corrected CONFIG_NFS issues.

At the Bakeathon, Jorge noted that when the MDS and DS use the same struct
nfs_client, umount would fail to free the nfs_client struct and the
keep-alive SEQUENCE compound would continue ad infinitum.

This was due to the fact that the DS reference to the MDS nfs_client would
prevent the umount from dropping the cl_count to zero. Moreover, the
DS refererence is only dropped by the deviceid dereference only called
by nfs4_deviceid_purge_client from nfs_free_client when the nfs_client
cl_count was zero.

See the patch comments for the solution description.

I've tested this solution against a 2-node C-mode filer where one node is an
MDS/DS and the other node a standalone MDS but uses the first node as a DS.

I tested all combinations, including mounting the MDS/DS node, and using pNFS
for I/O. Then mounting the solo MDS node, and using pNFS for I/O (which uses
the MDS/DS node as a DS), then umounting one of the mount points, doing pNFS
I/O and then umount the other.

In all cases, umount destroyed the appropriate nfs_client, and associated
session.


Andy Adamson (1):
  NFSv4.1 Fix umount when filelayout DS is also the MDS

 fs/nfs/client.c            |   88 ++++++++++++++++++++++++++++++++++++++++++-
 fs/nfs/internal.h          |    1 +
 fs/nfs/nfs4filelayoutdev.c |   29 ++++++++++++--
 include/linux/nfs_fs_sb.h  |    1 +
 4 files changed, 112 insertions(+), 7 deletions(-)

-- 
1.7.6.4


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2012-06-15 21:35 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-06-14 16:12 [PATCH Version 2 0/1] NFSv4.1 Fix umount when filelayout DS is also the MDS andros
2012-06-14 16:12 ` [PATCH Version 2 1/1] " andros
2012-06-14 17:21   ` Myklebust, Trond
2012-06-14 21:52     ` Adamson, Andy
2012-06-15 21:35       ` Myklebust, Trond

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).