@@ -177,7 +177,11 @@ static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *
{
int res = 0;
- res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
+ if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
+ res = nfs4_proc_delegreturn(inode,
+ delegation->cred,
+ &delegation->stateid,
+ issync);
nfs_free_delegation(delegation);
return res;
}
@@ -364,11 +368,13 @@ static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation
{
struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
struct nfs_inode *nfsi = NFS_I(inode);
- int err;
+ int err = 0;
if (delegation == NULL)
return 0;
do {
+ if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
+ break;
err = nfs_delegation_claim_opens(inode, &delegation->stateid);
if (!issync || err != -EAGAIN)
break;
@@ -589,10 +595,23 @@ static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *cl
rcu_read_unlock();
}
+static void nfs_revoke_delegation(struct inode *inode)
+{
+ struct nfs_delegation *delegation;
+ rcu_read_lock();
+ delegation = rcu_dereference(NFS_I(inode)->delegation);
+ if (delegation != NULL) {
+ set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
+ nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
+ }
+ rcu_read_unlock();
+}
+
void nfs_remove_bad_delegation(struct inode *inode)
{
struct nfs_delegation *delegation;
+ nfs_revoke_delegation(inode);
delegation = nfs_inode_detach_delegation(inode);
if (delegation) {
nfs_inode_find_state_and_recover(inode, &delegation->stateid);
@@ -31,6 +31,7 @@ enum {
NFS_DELEGATION_RETURN_IF_CLOSED,
NFS_DELEGATION_REFERENCED,
NFS_DELEGATION_RETURNING,
+ NFS_DELEGATION_REVOKED,
};
int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
@@ -1647,7 +1647,7 @@ static int nfs4_handle_delegation_recall_error(struct nfs_server *server, struct
nfs_inode_find_state_and_recover(state->inode,
stateid);
nfs4_schedule_stateid_recovery(server, state);
- return 0;
+ return -EAGAIN;
case -NFS4ERR_DELAY:
case -NFS4ERR_GRACE:
set_bit(NFS_DELEGATED_STATE, &state->flags);
This is a note to let you know that I have just added a patch titled NFSv4: Fix races between nfs_remove_bad_delegation() and delegation return to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 17825d7294968169ba8bfc40945a67de7d64032e Mon Sep 17 00:00:00 2001 From: Trond Myklebust <trond.myklebust@primarydata.com> Date: Mon, 10 Nov 2014 18:43:56 -0500 Subject: NFSv4: Fix races between nfs_remove_bad_delegation() and delegation return commit 869f9dfa4d6d57b79e0afc3af14772c2a023eeb1 upstream. Any attempt to call nfs_remove_bad_delegation() while a delegation is being returned is currently a no-op. This means that we can end up looping forever in nfs_end_delegation_return() if something causes the delegation to be revoked. This patch adds a mechanism whereby the state recovery code can communicate to the delegation return code that the delegation is no longer valid and that it should not be used when reclaiming state. It also changes the return value for nfs4_handle_delegation_recall_error() to ensure that nfs_end_delegation_return() does not reattempt the lock reclaim before state recovery is done. http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@mail.gmail.com Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- fs/nfs/delegation.c | 23 +++++++++++++++++++++-- fs/nfs/delegation.h | 1 + fs/nfs/nfs4proc.c | 2 +- 3 files changed, 23 insertions(+), 3 deletions(-) -- 2.1.0