[V4] btrfs: implement delayed inode items operation

Commit Message

Chris Mason March 21, 2011, 12:33 a.m. UTC

None

Patch

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 727d9a8..02e9390 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -32,7 +32,8 @@  int __init btrfs_delayed_inode_init(void)
 	delayed_node_cache = kmem_cache_create("delayed_node",
 					sizeof(struct btrfs_delayed_node),
 					0,
-					SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+					SLAB_RECLAIM_ACCOUNT |
+					SLAB_MEM_SPREAD | SLAB_DESTROY_BY_RCU,
 					NULL);
 	if (!delayed_node_cache)
 		return -ENOMEM;
@@ -90,22 +91,35 @@  static struct btrfs_delayed_node *btrfs_get_or_create_delayed_node(
 	struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
 	struct btrfs_root *root = btrfs_inode->root;
 
-	if (btrfs_inode->delayed_node) {
-		node = btrfs_inode->delayed_node;
-		atomic_inc(&node->refs);	/* can be accessed */
-		return node;
+again:
+	rcu_read_lock();
+again_rcu:
+	node = btrfs_inode->delayed_node;
+	if (node) {
+		if (atomic_inc_not_zero(&node->refs)) {
+			rcu_read_unlock();
+			return node;
+		}
+printk("racing on node access!\n");
+		goto again_rcu;
 	}
+	rcu_read_unlock();
 
 	node = kmem_cache_alloc(delayed_node_cache, GFP_NOFS);
 	if (!node)
 		return ERR_PTR(-ENOMEM);
 	btrfs_init_delayed_node(node, root->objectid, inode->i_ino);
 
-	btrfs_inode->delayed_node = node;
 	node->delayed_root = btrfs_get_delayed_root(root);
 	atomic_inc(&node->refs);	/* cached in the btrfs inode */
 	atomic_inc(&node->refs);	/* can be accessed */
 
+	if (cmpxchg(&BTRFS_I(inode)->delayed_node, NULL, node)) {
+		kmem_cache_free(delayed_node_cache, node);
+printk("racing on new node insertion!\n");
+		goto again;
+	}
+
 	return node;
 }
 
@@ -1167,7 +1181,7 @@  static void btrfs_async_run_delayed_node_done(struct btrfs_work *work)
 	nr = trans->blocks_used;
 
 	btrfs_end_transaction_dmeta(trans, root);
-	btrfs_btree_balance_dirty(root, nr);
+	__btrfs_btree_balance_dirty(root, nr);
 free_path:
 	btrfs_free_path(path);
 out:
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 0f589b1..0c6c336 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2649,6 +2649,28 @@  void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
 		balance_dirty_pages_ratelimited_nr(
 				   root->fs_info->btree_inode->i_mapping, 1);
 	}
+	btrfs_balance_delayed_items(root);
+	return;
+}
+
+void __btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
+{
+	/*
+	 * looks as though older kernels can get into trouble with
+	 * this code, they end up stuck in balance_dirty_pages forever
+	 */
+	u64 num_dirty;
+	unsigned long thresh = 32 * 1024 * 1024;
+
+	if (current->flags & PF_MEMALLOC)
+		return;
+
+	num_dirty = root->fs_info->dirty_metadata_bytes;
+
+	if (num_dirty > thresh) {
+		balance_dirty_pages_ratelimited_nr(
+				   root->fs_info->btree_inode->i_mapping, 1);
+	}
 	return;
 }
 
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 07b20dc..aca35af 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -71,6 +71,7 @@  int btrfs_insert_dev_radix(struct btrfs_root *root,
 			   u64 block_start,
 			   u64 num_blocks);
 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr);
+void __btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr);
 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root);
 void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
 void btrfs_mark_buffer_dirty_nonblocking(struct extent_buffer *buf);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6b238b2..ef240d8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4449,6 +4449,8 @@  void btrfs_dirty_inode(struct inode *inode)
 		}
 	}
 	btrfs_end_transaction(trans, root);
+	if (BTRFS_I(inode)->delayed_node)
+		btrfs_balance_delayed_items(root);
 }
 
 /*
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 31b328b..8f0ca33 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -483,8 +483,6 @@  int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 	ret = __btrfs_end_transaction(trans, root, 0, 1);
 	if (ret)
 		return ret;
-
-	btrfs_balance_delayed_items(root);
 	return 0;
 }
 
@@ -496,8 +494,6 @@  int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
 	ret = __btrfs_end_transaction(trans, root, 1, 1);
 	if (ret)
 		return ret;
-
-	btrfs_balance_delayed_items(root);
 	return 0;
 }
 
@@ -509,8 +505,6 @@  int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
 	ret = __btrfs_end_transaction(trans, root, 0, 0);
 	if (ret)
 		return ret;
-
-	btrfs_balance_delayed_items(root);
 	return 0;
 }