Btrfs: implement memory reclaim for leaf reference cache

[deliverable/linux.git] / fs / btrfs / ref-cache.c

diff --git a/fs/btrfs/ref-cache.c b/fs/btrfs/ref-cache.c
index ec9587784a3dc2098e2073b3c9faff827a5d9bf1..272b9890c9826d07a0564e7fe0d7c27bb402b81e 100644 (file)
--- a/fs/btrfs/ref-cache.c
+++ b/fs/btrfs/ref-cache.c
@@ -21,12 +21,18 @@
 #include "ref-cache.h"
 #include "transaction.h"
 
-struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(int nr_extents)
+struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
+                                           int nr_extents)
 {
        struct btrfs_leaf_ref *ref;
+       size_t size = btrfs_leaf_ref_size(nr_extents);
 
-       ref = kmalloc(btrfs_leaf_ref_size(nr_extents), GFP_NOFS);
+       ref = kmalloc(size, GFP_NOFS);
        if (ref) {
+               spin_lock(&root->fs_info->ref_cache_lock);
+               root->fs_info->total_ref_cache_size += size;
+               spin_unlock(&root->fs_info->ref_cache_lock);
+
                memset(ref, 0, sizeof(*ref));
                atomic_set(&ref->usage, 1);
                INIT_LIST_HEAD(&ref->list);
@@ -34,14 +40,20 @@ struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(int nr_extents)
        return ref;
 }
 
-void btrfs_free_leaf_ref(struct btrfs_leaf_ref *ref)
+void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 {
        if (!ref)
                return;
        WARN_ON(atomic_read(&ref->usage) == 0);
        if (atomic_dec_and_test(&ref->usage)) {
+               size_t size = btrfs_leaf_ref_size(ref->nritems);
+
                BUG_ON(ref->in_tree);
                kfree(ref);
+
+               spin_lock(&root->fs_info->ref_cache_lock);
+               root->fs_info->total_ref_cache_size -= size;
+               spin_unlock(&root->fs_info->ref_cache_lock);
        }
 }
 
@@ -64,7 +76,7 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
                else
                        return parent;
        }
-       
+
        entry = rb_entry(node, struct btrfs_leaf_ref, rb_node);
        entry->in_tree = 1;
        rb_link_node(node, parent, p);
@@ -91,9 +103,8 @@ static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
        return NULL;
 }
 
-int btrfs_remove_leaf_refs(struct btrfs_root *root)
+int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen)
 {
-       struct rb_node *rb;
        struct btrfs_leaf_ref *ref = NULL;
        struct btrfs_leaf_ref_tree *tree = root->ref_tree;
 
@@ -101,17 +112,18 @@ int btrfs_remove_leaf_refs(struct btrfs_root *root)
                return 0;
 
        spin_lock(&tree->lock);
-       while(!btrfs_leaf_ref_tree_empty(tree)) {
-               rb = rb_first(&tree->root);
-               ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node);
+       while(!list_empty(&tree->list)) {
+               ref = list_entry(tree->list.next, struct btrfs_leaf_ref, list);
+               BUG_ON(!ref->in_tree);
+               if (ref->root_gen > max_root_gen)
+                       break;
+
                rb_erase(&ref->rb_node, &tree->root);
                ref->in_tree = 0;
                list_del_init(&ref->list);
 
                spin_unlock(&tree->lock);
-
-               btrfs_free_leaf_ref(ref);
-
+               btrfs_free_leaf_ref(root, ref);
                cond_resched();
                spin_lock(&tree->lock);
        }
@@ -143,7 +155,6 @@ int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 {
        int ret = 0;
        struct rb_node *rb;
-       size_t size = btrfs_leaf_ref_size(ref->nritems);
        struct btrfs_leaf_ref_tree *tree = root->ref_tree;
 
        spin_lock(&tree->lock);
@@ -151,9 +162,6 @@ int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
        if (rb) {
                ret = -EEXIST;
        } else {
-               spin_lock(&root->fs_info->ref_cache_lock);
-               root->fs_info->total_ref_cache_size += size;
-               spin_unlock(&root->fs_info->ref_cache_lock);
                atomic_inc(&ref->usage);
                list_add_tail(&ref->list, &tree->list);
        }
@@ -163,15 +171,10 @@ int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 
 int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 {
-       size_t size = btrfs_leaf_ref_size(ref->nritems);
        struct btrfs_leaf_ref_tree *tree = root->ref_tree;
 
        BUG_ON(!ref->in_tree);
        spin_lock(&tree->lock);
-       
-       spin_lock(&root->fs_info->ref_cache_lock);
-       root->fs_info->total_ref_cache_size -= size;
-       spin_unlock(&root->fs_info->ref_cache_lock);
 
        rb_erase(&ref->rb_node, &tree->root);
        ref->in_tree = 0;
@@ -179,7 +182,6 @@ int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 
        spin_unlock(&tree->lock);
 
-       btrfs_free_leaf_ref(ref);
+       btrfs_free_leaf_ref(root, ref);
        return 0;
 }
-