[PATCH] NFSv4: Fix an infinite looping problem with thenfs4_state_manager

From: Trond Myklebust
Date: Mon Aug 24 2009 - 19:21:40 EST

Commit 76db6d9500caeaa774a3e32a997eba30bbdc176b (nfs41: add session setup
to the state manager) introduces an infinite loop possibility in the NFSv4
state manager. By first checking nfs4_has_session() before clearing the
NFS4CLNT_SESSION_SETUP flag, it allows for a situation where someone sets
that flag, but it never gets cleared, and so the state manager loops.

In fact commit c3fad1b1aaf850bf692642642ace7cd0d64af0a3 (nfs41: add session
reset to state manager) causes this to happen every time we get a network
partition error.

Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Tested-by: Daniel J Blueman <daniel.blueman@xxxxxxxxx>

fs/nfs/nfs4state.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 65ca8c1..1434080 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1250,8 +1250,8 @@ static void nfs4_state_manager(struct nfs_client *clp)
/* Initialize or reset the session */
- if (nfs4_has_session(clp) &&
- test_and_clear_bit(NFS4CLNT_SESSION_SETUP, &clp->cl_state)) {
+ if (test_and_clear_bit(NFS4CLNT_SESSION_SETUP, &clp->cl_state)
+ && nfs4_has_session(clp)) {
if (clp->cl_cons_state == NFS_CS_SESSION_INITING)
status = nfs4_initialize_session(clp);

Trond Myklebust
Linux NFS client maintainer

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/