nfsd4.1: fix session memory use calculation
Unbalanced calculations on creation and destruction of sessions could
cause our estimate of cache memory used to become negative, sometimes
resulting in spurious SERVERFAULT returns to client CREATE_SESSION
requests.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fcb9817..c171371 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -629,10 +629,13 @@
free_session(struct kref *kref)
{
struct nfsd4_session *ses;
+ int mem;
ses = container_of(kref, struct nfsd4_session, se_ref);
spin_lock(&nfsd_drc_lock);
- nfsd_drc_mem_used -= ses->se_fchannel.maxreqs * NFSD_SLOT_CACHE_SIZE;
+ mem = ses->se_fchannel.maxreqs
+ * (ses->se_fchannel.maxresp_cached - NFSD_MIN_HDR_SEQ_SZ);
+ nfsd_drc_mem_used -= mem;
spin_unlock(&nfsd_drc_lock);
free_session_slots(ses);
kfree(ses);