[src/trunk]: src/sys Add vcache operations to support key changes:

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e9b474c1d053
branches:  trunk
changeset: 797081:e9b474c1d053
user:      hannken <hannken%NetBSD.org@localhost>
date:      Sat Jul 05 09:33:15 2014 +0000

description:
Add vcache operations to support key changes:

vcache_rekey_enter locks the old cache node and creates and locks the
  new cache node.  It is an error if the new cache node exists.

vcache_rekey_exit removes the old cache node and finalizes and
  unlocks the new cache node.

No objections on tech-kern@

Welcome to 6.99.46

diffstat:

 sys/kern/vfs_vnode.c |  86 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 sys/sys/param.h      |   4 +-
 sys/sys/vnode.h      |   6 +++-
 3 files changed, 91 insertions(+), 5 deletions(-)

diffs (145 lines):

diff -r d212564b4bbb -r e9b474c1d053 sys/kern/vfs_vnode.c
--- a/sys/kern/vfs_vnode.c      Sat Jul 05 09:32:48 2014 +0000
+++ b/sys/kern/vfs_vnode.c      Sat Jul 05 09:33:15 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_vnode.c,v 1.36 2014/05/08 08:21:53 hannken Exp $   */
+/*     $NetBSD: vfs_vnode.c,v 1.37 2014/07/05 09:33:15 hannken Exp $   */
 
 /*-
  * Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -116,7 +116,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.36 2014/05/08 08:21:53 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.37 2014/07/05 09:33:15 hannken Exp $");
 
 #define _VFS_VNODE_PRIVATE
 
@@ -1324,6 +1324,88 @@
 }
 
 /*
+ * Prepare key change: lock old and new cache node.
+ * Return an error if the new node already exists.
+ */
+int
+vcache_rekey_enter(struct mount *mp, struct vnode *vp,
+    const void *old_key, size_t old_key_len,
+    const void *new_key, size_t new_key_len)
+{
+       uint32_t old_hash, new_hash;
+       struct vcache_key old_vcache_key, new_vcache_key;
+       struct vcache_node *node, *new_node;
+
+       old_vcache_key.vk_mount = mp;
+       old_vcache_key.vk_key = old_key;
+       old_vcache_key.vk_key_len = old_key_len;
+       old_hash = vcache_hash(&old_vcache_key);
+
+       new_vcache_key.vk_mount = mp;
+       new_vcache_key.vk_key = new_key;
+       new_vcache_key.vk_key_len = new_key_len;
+       new_hash = vcache_hash(&new_vcache_key);
+
+       new_node = pool_cache_get(vcache.pool, PR_WAITOK);
+       new_node->vn_vnode = NULL;
+       new_node->vn_key = new_vcache_key;
+
+       mutex_enter(&vcache.lock);
+       node = vcache_hash_lookup(&new_vcache_key, new_hash);
+       if (node != NULL) {
+               mutex_exit(&vcache.lock);
+               pool_cache_put(vcache.pool, new_node);
+               return EEXIST;
+       }
+       SLIST_INSERT_HEAD(&vcache.hashtab[new_hash & vcache.hashmask],
+           new_node, vn_hash);
+       node = vcache_hash_lookup(&old_vcache_key, old_hash);
+       KASSERT(node != NULL);
+       KASSERT(node->vn_vnode == vp);
+       node->vn_vnode = NULL;
+       node->vn_key = old_vcache_key;
+       mutex_exit(&vcache.lock);
+       return 0;
+}
+
+/*
+ * Key change complete: remove old node and unlock new node.
+ */
+void
+vcache_rekey_exit(struct mount *mp, struct vnode *vp,
+    const void *old_key, size_t old_key_len,
+    const void *new_key, size_t new_key_len)
+{
+       uint32_t old_hash, new_hash;
+       struct vcache_key old_vcache_key, new_vcache_key;
+       struct vcache_node *node;
+
+       old_vcache_key.vk_mount = mp;
+       old_vcache_key.vk_key = old_key;
+       old_vcache_key.vk_key_len = old_key_len;
+       old_hash = vcache_hash(&old_vcache_key);
+
+       new_vcache_key.vk_mount = mp;
+       new_vcache_key.vk_key = new_key;
+       new_vcache_key.vk_key_len = new_key_len;
+       new_hash = vcache_hash(&new_vcache_key);
+
+       mutex_enter(&vcache.lock);
+       node = vcache_hash_lookup(&new_vcache_key, new_hash);
+       KASSERT(node != NULL && node->vn_vnode == NULL);
+       KASSERT(node->vn_key.vk_key_len == new_key_len);
+       node->vn_vnode = vp;
+       node->vn_key = new_vcache_key;
+       node = vcache_hash_lookup(&old_vcache_key, old_hash);
+       KASSERT(node != NULL);
+       KASSERT(node->vn_vnode == NULL);
+       SLIST_REMOVE(&vcache.hashtab[old_hash & vcache.hashmask],
+           node, vcache_node, vn_hash);
+       mutex_exit(&vcache.lock);
+       pool_cache_put(vcache.pool, node);
+}
+
+/*
  * Remove a vnode / fs node pair from the cache.
  */
 void
diff -r d212564b4bbb -r e9b474c1d053 sys/sys/param.h
--- a/sys/sys/param.h   Sat Jul 05 09:32:48 2014 +0000
+++ b/sys/sys/param.h   Sat Jul 05 09:33:15 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: param.h,v 1.455 2014/07/01 13:25:21 rtr Exp $  */
+/*     $NetBSD: param.h,v 1.456 2014/07/05 09:33:15 hannken Exp $      */
 
 /*-
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -63,7 +63,7 @@
  *     2.99.9          (299000900)
  */
 
-#define        __NetBSD_Version__      699004500       /* NetBSD 6.99.45 */
+#define        __NetBSD_Version__      699004600       /* NetBSD 6.99.46 */
 
 #define __NetBSD_Prereq__(M,m,p) (((((M) * 100000000) + \
     (m) * 1000000) + (p) * 100) <= __NetBSD_Version__)
diff -r d212564b4bbb -r e9b474c1d053 sys/sys/vnode.h
--- a/sys/sys/vnode.h   Sat Jul 05 09:32:48 2014 +0000
+++ b/sys/sys/vnode.h   Sat Jul 05 09:33:15 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vnode.h,v 1.248 2014/05/25 13:51:26 hannken Exp $      */
+/*     $NetBSD: vnode.h,v 1.249 2014/07/05 09:33:15 hannken Exp $      */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -557,6 +557,10 @@
 void   vnfree(struct vnode *);
 void   vremfree(struct vnode *);
 int    vcache_get(struct mount *, const void *, size_t, struct vnode **);
+int    vcache_rekey_enter(struct mount *, struct vnode *,
+           const void *, size_t, const void *, size_t);
+void   vcache_rekey_exit(struct mount *, struct vnode *,
+           const void *, size_t, const void *, size_t);
 void   vcache_remove(struct mount *, const void *, size_t);
 
 /* see vnsubr(9) */