NFS: Add a new ACCESS rpc call cache to the linux nfs client
The current access cache only allows one entry at a time to be cached for each
inode. Add a per-inode red-black tree in order to allow more than one to
be cached at a time.
Should significantly cut down the time spent in path traversal for shared
directories such as ${PATH}, /usr/share, etc.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e7ffb4d..094afde 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1638,35 +1638,134 @@
return error;
}
+static void nfs_access_free_entry(struct nfs_access_entry *entry)
+{
+ put_rpccred(entry->cred);
+ kfree(entry);
+}
+
+static void __nfs_access_zap_cache(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct rb_root *root_node = &nfsi->access_cache;
+ struct rb_node *n, *dispose = NULL;
+ struct nfs_access_entry *entry;
+
+ /* Unhook entries from the cache */
+ while ((n = rb_first(root_node)) != NULL) {
+ entry = rb_entry(n, struct nfs_access_entry, rb_node);
+ rb_erase(n, root_node);
+ n->rb_left = dispose;
+ dispose = n;
+ }
+ nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
+ spin_unlock(&inode->i_lock);
+
+ /* Now kill them all! */
+ while (dispose != NULL) {
+ n = dispose;
+ dispose = n->rb_left;
+ nfs_access_free_entry(rb_entry(n, struct nfs_access_entry, rb_node));
+ }
+}
+
+void nfs_access_zap_cache(struct inode *inode)
+{
+ spin_lock(&inode->i_lock);
+ /* This will release the spinlock */
+ __nfs_access_zap_cache(inode);
+}
+
+static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred)
+{
+ struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
+ struct nfs_access_entry *entry;
+
+ while (n != NULL) {
+ entry = rb_entry(n, struct nfs_access_entry, rb_node);
+
+ if (cred < entry->cred)
+ n = n->rb_left;
+ else if (cred > entry->cred)
+ n = n->rb_right;
+ else
+ return entry;
+ }
+ return NULL;
+}
+
int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
{
struct nfs_inode *nfsi = NFS_I(inode);
- struct nfs_access_entry *cache = &nfsi->cache_access;
+ struct nfs_access_entry *cache;
+ int err = -ENOENT;
- if (cache->cred != cred
- || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
- || (nfsi->cache_validity & NFS_INO_INVALID_ACCESS))
- return -ENOENT;
- memcpy(res, cache, sizeof(*res));
- return 0;
+ spin_lock(&inode->i_lock);
+ if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
+ goto out_zap;
+ cache = nfs_access_search_rbtree(inode, cred);
+ if (cache == NULL)
+ goto out;
+ if (time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)))
+ goto out_stale;
+ res->jiffies = cache->jiffies;
+ res->cred = cache->cred;
+ res->mask = cache->mask;
+ err = 0;
+out:
+ spin_unlock(&inode->i_lock);
+ return err;
+out_stale:
+ rb_erase(&cache->rb_node, &nfsi->access_cache);
+ spin_unlock(&inode->i_lock);
+ nfs_access_free_entry(cache);
+ return -ENOENT;
+out_zap:
+ /* This will release the spinlock */
+ __nfs_access_zap_cache(inode);
+ return -ENOENT;
+}
+
+static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set)
+{
+ struct rb_root *root_node = &NFS_I(inode)->access_cache;
+ struct rb_node **p = &root_node->rb_node;
+ struct rb_node *parent = NULL;
+ struct nfs_access_entry *entry;
+
+ spin_lock(&inode->i_lock);
+ while (*p != NULL) {
+ parent = *p;
+ entry = rb_entry(parent, struct nfs_access_entry, rb_node);
+
+ if (set->cred < entry->cred)
+ p = &parent->rb_left;
+ else if (set->cred > entry->cred)
+ p = &parent->rb_right;
+ else
+ goto found;
+ }
+ rb_link_node(&set->rb_node, parent, p);
+ rb_insert_color(&set->rb_node, root_node);
+ spin_unlock(&inode->i_lock);
+ return;
+found:
+ rb_replace_node(parent, &set->rb_node, root_node);
+ spin_unlock(&inode->i_lock);
+ nfs_access_free_entry(entry);
}
void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
{
- struct nfs_inode *nfsi = NFS_I(inode);
- struct nfs_access_entry *cache = &nfsi->cache_access;
-
- if (cache->cred != set->cred) {
- if (cache->cred)
- put_rpccred(cache->cred);
- cache->cred = get_rpccred(set->cred);
- }
- /* FIXME: replace current access_cache BKL reliance with inode->i_lock */
- spin_lock(&inode->i_lock);
- nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
- spin_unlock(&inode->i_lock);
+ struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
+ if (cache == NULL)
+ return;
+ RB_CLEAR_NODE(&cache->rb_node);
cache->jiffies = set->jiffies;
+ cache->cred = get_rpccred(set->cred);
cache->mask = set->mask;
+
+ nfs_access_add_rbtree(inode, cache);
}
static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)