Ensure that we deal correctly with the case where the server sends us a
newer instance of the same delegation. If the stateids match, but the
sequence numbers differ, then treat the new delegation as if it were
an atomic upgrade.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxxxxxxx>
---
fs/nfs/delegation.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 7f3f60641344..16b754ee0d09 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -301,6 +301,17 @@ nfs_inode_detach_delegation(struct inode *inode)
return nfs_detach_delegation(nfsi, delegation, server);
}
+static void
+nfs_update_inplace_delegation(struct nfs_delegation *delegation,
+ const struct nfs_delegation *update)
+{
+ if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
+ delegation->stateid.seqid = update->stateid.seqid;
+ smp_wmb();
+ delegation->type = update->type;
+ }
+}
+
/**
* nfs_inode_set_delegation - set up a delegation on an inode
* @inode: inode to which delegation applies
@@ -334,9 +345,12 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
old_delegation = rcu_dereference_protected(nfsi->delegation,
lockdep_is_held(&clp->cl_lock));
if (old_delegation != NULL) {
- if (nfs4_stateid_match(&delegation->stateid,
- &old_delegation->stateid) &&
- delegation->type == old_delegation->type) {
+ /* Is this an update of the existing delegation? */
+ if (nfs4_stateid_match_other(&old_delegation->stateid,
+ &delegation->stateid)) {
+ nfs_update_inplace_delegation(old_delegation,
+ delegation);
+ nfsi->delegation_state = old_delegation->type;
goto out;
}
/*
--
2.1.0
--
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