Use now preferred SipHash24 functions. This also means we shouldn't
need to hash in the value of the dirhash pointer itself, which confuses
me every time I look at it.
Index: ufs/ufs_dirhash.c
===================================================================
RCS file: /cvs/src/sys/ufs/ufs/ufs_dirhash.c,v
retrieving revision 1.30
diff -u -p -r1.30 ufs_dirhash.c
--- ufs/ufs_dirhash.c 14 Sep 2014 14:17:27 -0000 1.30
+++ ufs/ufs_dirhash.c 3 Dec 2014 03:47:22 -0000
@@ -42,9 +42,10 @@ __FBSDID("$FreeBSD: src/sys/ufs/ufs/ufs_
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
-#include <sys/hash.h>
#include <sys/mutex.h>
+#include <crypto/siphash.h>
+
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/dir.h>
@@ -62,6 +63,7 @@ int ufs_dirhashmaxmem;
int ufs_dirhashmem;
int ufs_dirhashcheck;
+SIPHASH_KEY ufsdirhash_key;
int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen);
void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff);
@@ -857,17 +859,7 @@ ufsdirhash_checkblock(struct inode *ip,
int
ufsdirhash_hash(struct dirhash *dh, char *name, int namelen)
{
- u_int32_t hash;
-
- /*
- * We hash the name and then some other bit of data that is
- * invariant over the dirhash's lifetime. Otherwise names
- * differing only in the last byte are placed close to one
- * another in the table, which is bad for linear probing.
- */
- hash = hash32_buf(name, namelen, HASHINIT);
- hash = hash32_buf(&dh, sizeof(dh), hash);
- return (hash % dh->dh_hlen);
+ return SipHash24(&ufsdirhash_key, name, namelen) % dh->dh_hlen;
}
/*
@@ -1059,6 +1051,7 @@ ufsdirhash_init(void)
pool_init(&ufsdirhash_pool, DH_NBLKOFF * sizeof(doff_t), 0, 0, 0,
"dirhash", &pool_allocator_nointr);
mtx_init(&ufsdirhash_mtx, IPL_NONE);
+ arc4random_buf(&ufsdirhash_key, sizeof(ufsdirhash_key));
TAILQ_INIT(&ufsdirhash_list);
#if defined (__sparc__) && !defined (__sparc64__)
if (!CPU_ISSUN4OR4C)
