@@ -104,7 +104,7 @@ void extent_io_tree_init(struct extent_io_tree *tree,
struct address_space *mapping, gfp_t mask)
{
tree->state = RB_ROOT;
- tree->buffer = RB_ROOT;
+ INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
tree->ops = NULL;
tree->dirty_bytes = 0;
spin_lock_init(&tree->lock);
@@ -235,50 +235,6 @@ static inline struct rb_node *tree_search(struct extent_io_tree *tree,
return ret;
}
-static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree,
- u64 offset, struct rb_node *node)
-{
- struct rb_root *root = &tree->buffer;
- struct rb_node **p = &root->rb_node;
- struct rb_node *parent = NULL;
- struct extent_buffer *eb;
-
- while (*p) {
- parent = *p;
- eb = rb_entry(parent, struct extent_buffer, rb_node);
-
- if (offset < eb->start)
- p = &(*p)->rb_left;
- else if (offset > eb->start)
- p = &(*p)->rb_right;
- else
- return eb;
- }
-
- rb_link_node(node, parent, p);
- rb_insert_color(node, root);
- return NULL;
-}
-
-static struct extent_buffer *buffer_search(struct extent_io_tree *tree,
- u64 offset)
-{
- struct rb_root *root = &tree->buffer;
- struct rb_node *n = root->rb_node;
- struct extent_buffer *eb;
-
- while (n) {
- eb = rb_entry(n, struct extent_buffer, rb_node);
- if (offset < eb->start)
- n = n->rb_left;
- else if (offset > eb->start)
- n = n->rb_right;
- else
- return eb;
- }
- return NULL;
-}
-
static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
struct extent_state *other)
{
@@ -3075,6 +3031,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
eb->len = len;
spin_lock_init(&eb->lock);
init_waitqueue_head(&eb->lock_wq);
+ INIT_RCU_HEAD(&eb->rcu_head);
#if LEAK_DEBUG
spin_lock_irqsave(&leak_lock, flags);
@@ -3143,16 +3100,16 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
struct page *p;
struct address_space *mapping = tree->mapping;
int uptodate = 1;
+ int ret;
- spin_lock(&tree->buffer_lock);
- eb = buffer_search(tree, start);
- if (eb) {
- atomic_inc(&eb->refs);
- spin_unlock(&tree->buffer_lock);
+ rcu_read_lock();
+ eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
+ if (eb && atomic_inc_not_zero(&eb->refs)) {
+ rcu_read_unlock();
mark_page_accessed(eb->first_page);
return eb;
}
- spin_unlock(&tree->buffer_lock);
+ rcu_read_unlock();
eb = __alloc_extent_buffer(tree, start, len, mask);
if (!eb)
@@ -3191,17 +3148,25 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
if (uptodate)
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
+ if (ret)
+ goto free_eb;
+
spin_lock(&tree->buffer_lock);
- exists = buffer_tree_insert(tree, start, &eb->rb_node);
- if (exists) {
+ ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
+ if (ret == -EEXIST) {
+ exists = radix_tree_lookup(&tree->buffer,
+ start >> PAGE_CACHE_SHIFT);
/* add one reference for the caller */
atomic_inc(&exists->refs);
spin_unlock(&tree->buffer_lock);
+ radix_tree_preload_end();
goto free_eb;
}
/* add one reference for the tree */
atomic_inc(&eb->refs);
spin_unlock(&tree->buffer_lock);
+ radix_tree_preload_end();
return eb;
free_eb:
@@ -3217,16 +3182,16 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
{
struct extent_buffer *eb;
- spin_lock(&tree->buffer_lock);
- eb = buffer_search(tree, start);
- if (eb)
- atomic_inc(&eb->refs);
- spin_unlock(&tree->buffer_lock);
-
- if (eb)
+ rcu_read_lock();
+ eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
+ if (eb && atomic_inc_not_zero(&eb->refs)) {
+ rcu_read_unlock();
mark_page_accessed(eb->first_page);
+ return eb;
+ }
+ rcu_read_unlock();
- return eb;
+ return NULL;
}
void free_extent_buffer(struct extent_buffer *eb)
@@ -3856,6 +3821,14 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
}
}
+static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
+{
+ struct extent_buffer *eb =
+ container_of(head, struct extent_buffer, rcu_head);
+
+ btrfs_release_extent_buffer(eb);
+}
+
int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
{
u64 start = page_offset(page);
@@ -3863,23 +3836,30 @@ int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
int ret = 1;
spin_lock(&tree->buffer_lock);
- eb = buffer_search(tree, start);
+ eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
if (!eb)
goto out;
- if (atomic_read(&eb->refs) > 1) {
+ if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
ret = 0;
goto out;
}
- if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
+
+ /*
+ * set @eb->refs to 0 if it is already 1, and then release the @eb.
+ * Or go back.
+ */
+ if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
ret = 0;
goto out;
}
- rb_erase(&eb->rb_node, &tree->buffer);
- /* at this point we can safely release the extent buffer */
- btrfs_release_extent_buffer(eb);
+ radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
out:
spin_unlock(&tree->buffer_lock);
+
+ /* at this point we can safely release the extent buffer */
+ if (atomic_read(&eb->refs) == 0)
+ call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
return ret;
}
@@ -85,7 +85,7 @@ struct extent_io_ops {
struct extent_io_tree {
struct rb_root state;
- struct rb_root buffer;
+ struct radix_tree_root buffer;
struct address_space *mapping;
u64 dirty_bytes;
spinlock_t lock;
@@ -123,7 +123,7 @@ struct extent_buffer {
unsigned long bflags;
atomic_t refs;
struct list_head leak_list;
- struct rb_node rb_node;
+ struct rcu_head rcu_head;
/* the spinlock is used to protect most operations */
spinlock_t lock;