btrfs_get_block, file read/write

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 50 insertions, 2 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 8e1e5b4ccfaf..4a0367d702b7 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -1,9 +1,57 @@
 #include <linux/module.h>
 #include "ctree.h"
+#include "disk-io.h"
 #include "transaction.h"
 
-int btrfs_create_file(struct btrfs_trans_handle *trans,
-		      struct btrfs_root *root, u64 dirid, u64 *objectid)
+int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root,
+			       u64 objectid, u64 offset,
+			       u64 num_blocks, u64 hint_block,
+			       u64 *result)
 {
+	struct btrfs_key ins;
+	int ret = 0;
+	struct btrfs_file_extent_item *item;
+	struct btrfs_key file_key;
+	struct btrfs_path path;
+
+	btrfs_init_path(&path);
+	ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
+				 (u64)-1, objectid, &ins);
+	BUG_ON(ret);
+	file_key.objectid = objectid;
+	file_key.offset = offset;
+	file_key.flags = 0;
+	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
+
+	ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
+				      sizeof(*item));
+	item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+			      struct btrfs_file_extent_item);
+	btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
+	btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
+	btrfs_set_file_extent_offset(item, 0);
+	btrfs_set_file_extent_num_blocks(item, ins.offset);
+	mark_buffer_dirty(path.nodes[0]);
+	*result = ins.objectid;
+	btrfs_release_path(root, &path);
 	return 0;
 }
+
+int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root,
+			     struct btrfs_path *path, u64 objectid,
+			     u64 blocknr, u64 num_blocks, int mod)
+{
+	int ret;
+	struct btrfs_key file_key;
+	int ins_len = mod < 0 ? -1 : 0;
+	int cow = mod != 0;
+
+	file_key.objectid = objectid;
+	file_key.offset = blocknr;
+	file_key.flags = 0;
+	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
+	ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
+	return ret;
+}