Re: [PATCH 04/20] btrfs-progs: add a helper for setting up a root node

We use this pattern in a few places, and will use it more with different
roots in the future.  Extract out this helper to read the root nodes.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
  kernel-shared/disk-io.c | 58 +++++++++++++++++++++--------------------
  1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/kernel-shared/disk-io.c b/kernel-shared/disk-io.c
index 3b3c4523..1f940221 100644
--- a/kernel-shared/disk-io.c
+++ b/kernel-shared/disk-io.c

@@ -578,12 +578,23 @@ void btrfs_setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
  	root->root_key.objectid = objectid;
  }

+static int read_root_node(struct btrfs_fs_info *fs_info,
+			  struct btrfs_root *root, u64 bytenr, u64 gen)

+{
+	root->node = read_tree_block(fs_info, bytenr, gen); > +	if (!extent_buffer_uptodate(root->node)) {
+		free_extent_buffer(root->node);
+		root->node = NULL;
+		return -EIO;
+	}
+	return 0;
+}
+
  static int find_and_setup_root(struct btrfs_root *tree_root,
  			       struct btrfs_fs_info *fs_info,
  			       u64 objectid, struct btrfs_root *root)
  {
  	int ret;
-	u64 generation;

  	btrfs_setup_root(root, fs_info, objectid);
  	ret = btrfs_find_last_root(tree_root, objectid,

@@ -591,13 +602,9 @@ static int find_and_setup_root(struct btrfs_root *tree_root,
  	if (ret)
  		return ret;

-	generation = btrfs_root_generation(&root->root_item);
-	root->node = read_tree_block(fs_info,
-			btrfs_root_bytenr(&root->root_item), generation);
-	if (!extent_buffer_uptodate(root->node))
-		return -EIO;
-
-	return 0;
+	return read_root_node(fs_info, root,
+			      btrfs_root_bytenr(&root->root_item),
+			      btrfs_root_generation(&root->root_item));
  }

  static int find_and_setup_log_root(struct btrfs_root *tree_root,

@@ -606,6 +613,7 @@ static int find_and_setup_log_root(struct btrfs_root *tree_root,
  {
  	u64 blocknr = btrfs_super_log_root(disk_super);
  	struct btrfs_root *log_root = malloc(sizeof(struct btrfs_root));
+	int ret;

  	if (!log_root)
  		return -ENOMEM;

@@ -615,20 +623,15 @@ static int find_and_setup_log_root(struct btrfs_root *tree_root,
  		return 0;
  	}

-	btrfs_setup_root(log_root, fs_info,
-			 BTRFS_TREE_LOG_OBJECTID);
-
-	log_root->node = read_tree_block(fs_info, blocknr,
-				     btrfs_super_generation(disk_super) + 1);
-
-	fs_info->log_root_tree = log_root;
-
-	if (!extent_buffer_uptodate(log_root->node)) {
-		free_extent_buffer(log_root->node);
+	btrfs_setup_root(log_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
+	ret = read_root_node(fs_info, log_root, blocknr,
+			     btrfs_super_generation(disk_super) + 1);
+	if (ret) {
  		free(log_root);
  		fs_info->log_root_tree = NULL;
-		return -EIO;
+		return ret;
  	}
+	fs_info->log_root_tree = log_root;

  	return 0;
  }

@@ -704,9 +707,9 @@ out:
  		return ERR_PTR(ret);
  	}
  	generation = btrfs_root_generation(&root->root_item);
-	root->node = read_tree_block(fs_info,
-			btrfs_root_bytenr(&root->root_item), generation);
-	if (!extent_buffer_uptodate(root->node)) {
+	ret = read_root_node(fs_info, root,
+			     btrfs_root_bytenr(&root->root_item), generation);
+	if (ret) {
  		free(root);
  		return ERR_PTR(-EIO);
  	}

@@ -970,8 +973,8 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
  		generation = btrfs_backup_tree_root_gen(backup);
  	}

-	root->node = read_tree_block(fs_info, root_tree_bytenr, generation);
-	if (!extent_buffer_uptodate(root->node)) {
+	ret = read_root_node(fs_info, root, root_tree_bytenr, generation);
+	if (ret) {
  		fprintf(stderr, "Couldn't read tree root\n");
  		return -EIO;
  	}

@@ -1179,10 +1182,9 @@ int btrfs_setup_chunk_tree_and_device_map(struct btrfs_fs_info *fs_info,
  	else
  		generation = 0;

-	fs_info->chunk_root->node = read_tree_block(fs_info,
-						    chunk_root_bytenr,
-						    generation);
-	if (!extent_buffer_uptodate(fs_info->chunk_root->node)) {
+	ret = read_root_node(fs_info, fs_info->chunk_root, chunk_root_bytenr,
+			     generation);
+	if (ret) {
  		if (fs_info->ignore_chunk_tree_error) {
  			warning("cannot read chunk root, continue anyway");
  			fs_info->chunk_root = NULL;