From: J. Bruce Fields <bfields@citi.umich.edu>
Date: Wed, 21 Oct 2009 21:54:13 +0000 (-0400)
Subject: nfsd4.1: fix session memory use calculation
X-Git-Tag: v2.6.33-rc8~37^2~40
X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=dd829c45640ff14d7a039af40b3b3975f1b2e484

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 @@ void
 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);