NFS: Add a global LRU list for the ACCESS cache

...in order to allow the addition of a memory shrinker.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 40 insertions, 1 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 094afded2b11..bf4f5ffda703 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1638,10 +1638,17 @@ out:
         return error;
 }
 
+static DEFINE_SPINLOCK(nfs_access_lru_lock);
+static LIST_HEAD(nfs_access_lru_list);
+static atomic_long_t nfs_access_nr_entries;
+
 static void nfs_access_free_entry(struct nfs_access_entry *entry)
 {
         put_rpccred(entry->cred);
         kfree(entry);
+        smp_mb__before_atomic_dec();
+        atomic_long_dec(&nfs_access_nr_entries);
+        smp_mb__after_atomic_dec();
 }
 
 static void __nfs_access_zap_cache(struct inode *inode)
@@ -1655,6 +1662,7 @@ static void __nfs_access_zap_cache(struct inode *inode)
         while ((n = rb_first(root_node)) != NULL) {
                 entry = rb_entry(n, struct nfs_access_entry, rb_node);
                 rb_erase(n, root_node);
+                list_del(&entry->lru);
                 n->rb_left = dispose;
                 dispose = n;
         }
@@ -1671,6 +1679,13 @@ static void __nfs_access_zap_cache(struct inode *inode)
 
 void nfs_access_zap_cache(struct inode *inode)
 {
+        /* Remove from global LRU init */
+        if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) {
+                spin_lock(&nfs_access_lru_lock);
+                list_del_init(&NFS_I(inode)->access_cache_inode_lru);
+                spin_unlock(&nfs_access_lru_lock);
+        }
+
         spin_lock(&inode->i_lock);
         /* This will release the spinlock */
         __nfs_access_zap_cache(inode);
@@ -1711,12 +1726,14 @@ int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs
         res->jiffies = cache->jiffies;
         res->cred = cache->cred;
         res->mask = cache->mask;
+        list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
         err = 0;
 out:
         spin_unlock(&inode->i_lock);
         return err;
 out_stale:
         rb_erase(&cache->rb_node, &nfsi->access_cache);
+        list_del(&cache->lru);
         spin_unlock(&inode->i_lock);
         nfs_access_free_entry(cache);
         return -ENOENT;
@@ -1728,7 +1745,8 @@ out_zap:
 
 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 nfs_inode *nfsi = NFS_I(inode);
+        struct rb_root *root_node = &nfsi->access_cache;
         struct rb_node **p = &root_node->rb_node;
         struct rb_node *parent = NULL;
         struct nfs_access_entry *entry;
@@ -1747,10 +1765,13 @@ static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *
         }
         rb_link_node(&set->rb_node, parent, p);
         rb_insert_color(&set->rb_node, root_node);
+        list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
         spin_unlock(&inode->i_lock);
         return;
 found:
         rb_replace_node(parent, &set->rb_node, root_node);
+        list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
+        list_del(&entry->lru);
         spin_unlock(&inode->i_lock);
         nfs_access_free_entry(entry);
 }
@@ -1766,6 +1787,18 @@ void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
         cache->mask = set->mask;
 
         nfs_access_add_rbtree(inode, cache);
+
+        /* Update accounting */
+        smp_mb__before_atomic_inc();
+        atomic_long_inc(&nfs_access_nr_entries);
+        smp_mb__after_atomic_inc();
+
+        /* Add inode to global LRU list */
+        if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) {
+                spin_lock(&nfs_access_lru_lock);
+                list_add_tail(&NFS_I(inode)->access_cache_inode_lru, &nfs_access_lru_list);
+                spin_unlock(&nfs_access_lru_lock);
+        }
 }
 
 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index b94ab060bb1e..6ed018c9aad2 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1104,6 +1104,8 @@ static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
                 INIT_LIST_HEAD(&nfsi->dirty);
                 INIT_LIST_HEAD(&nfsi->commit);
                 INIT_LIST_HEAD(&nfsi->open_files);
+                INIT_LIST_HEAD(&nfsi->access_cache_entry_lru);
+                INIT_LIST_HEAD(&nfsi->access_cache_inode_lru);
                 INIT_RADIX_TREE(&nfsi->nfs_page_tree, GFP_ATOMIC);
                 atomic_set(&nfsi->data_updates, 0);
                 nfsi->ndirty = 0;
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index cc013ed2e52e..a36e01cd6321 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -71,6 +71,7 @@
  */
 struct nfs_access_entry {
         struct rb_node          rb_node;
+        struct list_head        lru;
         unsigned long           jiffies;
         struct rpc_cred *       cred;
         int                     mask;
@@ -148,6 +149,8 @@ struct nfs_inode {
         atomic_t                data_updates;
 
         struct rb_root          access_cache;
+        struct list_head        access_cache_entry_lru;
+        struct list_head        access_cache_inode_lru;
 #ifdef CONFIG_NFS_V3_ACL
         struct posix_acl        *acl_access;
         struct posix_acl        *acl_default;
@@ -201,6 +204,7 @@ struct nfs_inode {
 #define NFS_INO_REVALIDATING    (0)             /* revalidating attrs */
 #define NFS_INO_ADVISE_RDPLUS   (1)             /* advise readdirplus */
 #define NFS_INO_STALE           (2)             /* possible stale inode */
+#define NFS_INO_ACL_LRU_SET     (3)             /* Inode is on the LRU list */
 
 static inline struct nfs_inode *NFS_I(struct inode *inode)
 {