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;
+}