Improve the hash function to handle clients which increment the XID
in the unexpected byte order, by folding down the top bits of the XID.
Signed-off-by: Greg Banks <gnb@xxxxxxx>
---
fs/nfsd/nfscache.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
Index: bfields/fs/nfsd/nfscache.c
===================================================================
--- bfields.orig/fs/nfsd/nfscache.c
+++ bfields/fs/nfsd/nfscache.c
@@ -35,12 +35,15 @@ static struct list_head lru_head;
static int cache_disabled = 1;
/*
- * Calculate the hash index from an XID.
+ * Calculate the hash index from an XID. Note, some clients increment
+ * their XIDs in host order, which can result in all the variation being
+ * in the top bits we see here. So we fold those bits down.
*/
static inline u32 request_hash(u32 xid)
{
u32 h = xid;
h ^= (xid >> 24);
+ h ^= ((xid & 0xff0000) >> 8);
return h & (HASHSIZE-1);
}
--
Greg
--
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