Return a locked struct buf from ufsdirhash_lookup() to avoid one

extra getblk/brelse sequence for each lookup. We already had this
buf in ufsdirhash_lookup(), so there was no point in brelse'ing it
only to have the caller immediately reaquire the same buffer.

This should make the case of sequential lookups marginally faster;
in my tests, sequential lookups with dirhash enabled are now only
around 1% slower than without dirhash.

3 files changed, 9 insertions, 9 deletions

diff --git a/sys/ufs/ufs/dirhash.h b/sys/ufs/ufs/dirhash.h
index 50cdc65..4aea6c1 100644
--- a/sys/ufs/ufs/dirhash.h
+++ b/sys/ufs/ufs/dirhash.h
@@ -111,7 +111,8 @@ struct dirhash {
 int	ufsdirhash_build(struct inode *);
 doff_t	ufsdirhash_findfree(struct inode *, int, int *);
 doff_t	ufsdirhash_enduseful(struct inode *);
-int	ufsdirhash_lookup(struct inode *, char *, int, doff_t *, doff_t *);
+int	ufsdirhash_lookup(struct inode *, char *, int, doff_t *, struct buf **,
+	    doff_t *);
 void	ufsdirhash_newblk(struct inode *, doff_t);
 void	ufsdirhash_add(struct inode *, struct direct *, doff_t);
 void	ufsdirhash_remove(struct inode *, struct direct *, doff_t);
diff --git a/sys/ufs/ufs/ufs_dirhash.c b/sys/ufs/ufs/ufs_dirhash.c
index cc2cda9..1a9262a 100644
--- a/sys/ufs/ufs/ufs_dirhash.c
+++ b/sys/ufs/ufs/ufs_dirhash.c
@@ -298,14 +298,15 @@ ufsdirhash_free(struct inode *ip)
  * Returns 0 on success, ENOENT if the entry does not exist, or
  * EJUSTRETURN if the caller should revert to a linear search.
  *
- * If successful, the directory offset is stored in *offp. If
+ * If successful, the directory offset is stored in *offp, and a
+ * pointer to a struct buf containing the entry is stored in *bpp. If
  * prevoffp is non-NULL, the offset of the previous entry within
  * the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry
  * is the first in a block, the start of the block is used).
  */
 int
 ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp,
-    doff_t *prevoffp)
+    struct buf **bpp, doff_t *prevoffp)
 {
 	struct dirhash *dh, *dh_next;
 	struct direct *dp;
@@ -428,7 +429,7 @@ restart:
 				dh->dh_seqopt = 1;
 			dh->dh_seqoff = offset + DIRSIZ(0, dp);
 
-			brelse(bp);
+			*bpp = bp;
 			*offp = offset;
 			return (0);
 		}
diff --git a/sys/ufs/ufs/ufs_lookup.c b/sys/ufs/ufs/ufs_lookup.c
index 2a3a71e..b4aa6a9 100644
--- a/sys/ufs/ufs/ufs_lookup.c
+++ b/sys/ufs/ufs/ufs_lookup.c
@@ -212,12 +212,10 @@ ufs_lookup(ap)
 		numdirpasses = 1;
 		entryoffsetinblock = 0; /* silence compiler warning */
 		switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
-		    &dp->i_offset, nameiop == DELETE ? &prevoff : NULL)) {
+		    &dp->i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
 		case 0:
-			error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset,
-			    (char **)&ep, &bp);
-			if (error)
-				return (error);
+			ep = (struct direct *)((char *)bp->b_data +
+			    (dp->i_offset & bmask));
 			goto foundentry;
 		case ENOENT:
 			dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);