[PATCH] kNFSd: Convert export-table to use new cache code

This introduces two caches, svc_export_cache (nfsd.exports) and
svc_expkey_cache (nfsd.fh).
nfsd.exports maps client+directory  ->  export options.
nfsd.fh maps client + filehandle-fragment -> directory.

A major part of this change is that export entries are now reference counted,
so we have to be careful  to keep those counts correct.

fs/nfsd/nfsfh.c

@@ -86,7 +86,7 @@ u32
 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 {
 	struct knfsd_fh	*fh = &fhp->fh_handle;
-	struct svc_export *exp;
+	struct svc_export *exp = NULL;
 	struct dentry	*dentry;
 	struct inode	*inode;
 	u32		error = 0;
@@ -144,13 +144,12 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 			exp = exp_find(rqstp->rq_client, 0, tfh);
 		}
 
-		/*
-		 * Look up the export entry.
-		 */
-		error = nfserr_stale; 
+		error = nfserr_dropit;
+		if (IS_ERR(exp))
+			goto out;
 
+		error = nfserr_stale; 
 		if (!exp)
-			/* export entry revoked */
 			goto out;
 
 		/* Check if the request originated from a secure port. */
@@ -221,6 +220,7 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 		dentry = fhp->fh_dentry;
 		exp = fhp->fh_export;
 	}
+	cache_get(&exp->h);
 
 	inode = dentry->d_inode;
 
@@ -263,6 +263,8 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 	}
 #endif
 out:
+	if (exp && !IS_ERR(exp))
+		exp_put(exp);
 	if (error == nfserr_stale)
 		nfsdstats.fh_stale++;
 	return error;
@@ -344,6 +346,7 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, st
 
 	fhp->fh_dentry = dentry; /* our internal copy */
 	fhp->fh_export = exp;
+	cache_get(&exp->h);
 
 	if (ref_fh_version == 0xca) {
 		/* old style filehandle please */
@@ -442,6 +445,7 @@ void
 fh_put(struct svc_fh *fhp)
 {
 	struct dentry * dentry = fhp->fh_dentry;
+	struct svc_export * exp = fhp->fh_export;
 	if (dentry) {
 		fh_unlock(fhp);
 		fhp->fh_dentry = NULL;
@@ -452,6 +456,10 @@ fh_put(struct svc_fh *fhp)
 #endif
 		nfsd_nr_put++;
 	}
+	if (exp) {
+		svc_export_put(&exp->h, &svc_export_cache);
+		fhp->fh_export = NULL;
+	}
 	return;
 }
 

fs/nfsd/vfs.c

@@ -135,6 +135,7 @@ nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 				dput(dentry);
 				dentry = dget(dparent);
 			} else {
+				exp_put(exp);
 				exp = exp2;
 			}
 			mntput(mnt);
@@ -157,11 +158,14 @@ nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 			exp2 = exp_get_by_name(exp->ex_client, mnt, mounts);
 			if (exp2 && EX_CROSSMNT(exp2)) {
 				/* successfully crossed mount point */
+				exp_put(exp);
 				exp = exp2;
 				dput(dentry);
 				dentry = mounts;
-			} else
+			} else {
+				if (exp2) exp_put(exp2);
 				dput(mounts);
+			}
 			mntput(mnt);
 		}
 	}

include/linux/nfsd/export.h

@@ -46,7 +46,7 @@
 #ifdef __KERNEL__
 
 struct svc_export {
-	struct list_head	ex_hash;
+	struct cache_head	h;
 	struct auth_domain *	ex_client;
 	int			ex_flags;
 	struct vfsmount *	ex_mnt;
@@ -61,7 +61,7 @@ struct svc_export {
  * for type 0 (dev/ino), one for type 1 (fsid)
  */
 struct svc_expkey {
-	struct list_head	ek_hash;
+	struct cache_head	h;
 
 	struct auth_domain *	ek_client;
 	int			ek_fsidtype;
@@ -98,14 +98,30 @@ int			exp_rootfh(struct auth_domain *,
 int			exp_pseudoroot(struct auth_domain *, struct svc_fh *fhp);
 int			nfserrno(int errno);
 
+extern void expkey_put(struct cache_head *item, struct cache_detail *cd);
+extern void svc_export_put(struct cache_head *item, struct cache_detail *cd);
+extern struct cache_detail svc_export_cache, svc_expkey_cache;
+
+static inline void exp_put(struct svc_export *exp)
+{
+	svc_export_put(&exp->h, &svc_export_cache);
+}
+
 static inline struct svc_export *
 exp_find(struct auth_domain *clp, int fsid_type, u32 *fsidv)
 {
 	struct svc_expkey *ek = exp_find_key(clp, fsid_type, fsidv);
-	if (ek)
-		return ek->ek_export;
-	else
-		return NULL;
+	if (ek && !IS_ERR(ek)) {
+		struct svc_export *exp = ek->ek_export;
+		int err;
+		cache_get(&exp->h);
+		expkey_put(&ek->h, &svc_expkey_cache);
+		if (exp &&
+		    (err = cache_check(&svc_export_cache, &exp->h))) 
+			exp = ERR_PTR(err);
+		return exp;
+	} else
+		return ERR_PTR(PTR_ERR(ek));
 }
 
 #endif /* __KERNEL__ */