Btrfs: Add inode map, and the start of file extent items

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

1 files changed, 136 insertions, 0 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
new file mode 100644
index 000000000000..f412b3392135
--- /dev/null
+++ b/fs/btrfs/inode-map.c
@@ -0,0 +1,136 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "kerncompat.h"
+#include "radix-tree.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+
+/*
+ * walks the btree of allocated inodes and find a hole.
+ */
+int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
+                             struct btrfs_root *fs_root,
+                             u64 dirid, u64 *objectid)
+{
+        struct btrfs_path path;
+        struct btrfs_key key;
+        int ret;
+        u64 hole_size = 0;
+        int slot = 0;
+        u64 last_ino;
+        int start_found;
+        struct btrfs_leaf *l;
+        struct btrfs_root *root = fs_root->fs_info->inode_root;
+        struct btrfs_key search_key;
+        u64 search_start = dirid;
+
+        if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
+                search_start = fs_root->fs_info->last_inode_alloc;
+
+        search_key.objectid = search_start;
+        search_key.flags = 0;
+        btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);
+        search_key.offset = 0;
+
+        btrfs_init_path(&path);
+        start_found = 0;
+        ret = btrfs_search_slot(trans, root, &search_key, &path, 0, 0);
+        if (ret < 0)
+                goto error;
+
+        if (path.slots[0] > 0)
+                path.slots[0]--;
+
+        while (1) {
+                l = &path.nodes[0]->leaf;
+                slot = path.slots[0];
+                if (slot >= btrfs_header_nritems(&l->header)) {
+                        ret = btrfs_next_leaf(root, &path);
+                        if (ret == 0)
+                                continue;
+                        if (ret < 0)
+                                goto error;
+                        if (!start_found) {
+                                *objectid = search_start;
+                                start_found = 1;
+                                goto found;
+                        }
+                        *objectid = last_ino > search_start ?
+                                last_ino : search_start;
+                        goto found;
+                }
+                btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
+                if (key.objectid >= search_start) {
+                        if (start_found) {
+                                if (last_ino < search_start)
+                                        last_ino = search_start;
+                                hole_size = key.objectid - last_ino;
+                                if (hole_size > 0) {
+                                        *objectid = last_ino;
+                                        goto found;
+                                }
+                        }
+                }
+                start_found = 1;
+                last_ino = key.objectid + 1;
+                path.slots[0]++;
+        }
+        // FIXME -ENOSPC
+found:
+        root->fs_info->last_inode_alloc = *objectid;
+        root->fs_info->last_inode_alloc_dirid = dirid;
+        btrfs_release_path(root, &path);
+        BUG_ON(*objectid < search_start);
+        return 0;
+error:
+        btrfs_release_path(root, &path);
+        return ret;
+}
+
+int btrfs_insert_inode_map(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *fs_root,
+                           u64 objectid, struct btrfs_key *location)
+{
+        int ret = 0;
+        struct btrfs_path path;
+        struct btrfs_inode_map_item *inode_item;
+        struct btrfs_key key;
+        struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
+
+        key.objectid = objectid;
+        key.flags = 0;
+        btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
+        key.offset = 0;
+        btrfs_init_path(&path);
+        ret = btrfs_insert_empty_item(trans, inode_root, &path, &key,
+                                      sizeof(struct btrfs_inode_map_item));
+        if (ret)
+                goto out;
+
+        inode_item = btrfs_item_ptr(&path.nodes[0]->leaf, path.slots[0],
+                                  struct btrfs_inode_map_item);
+        btrfs_cpu_key_to_disk(&inode_item->key, location);
+out:
+        btrfs_release_path(inode_root, &path);
+        return ret;
+}
+
+int btrfs_lookup_inode_map(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *fs_root, struct btrfs_path *path,
+                           u64 objectid, int mod)
+{
+        int ret;
+        struct btrfs_key key;
+        int ins_len = mod < 0 ? -1 : 0;
+        int cow = mod != 0;
+        struct btrfs_root *inode_root = fs_root->fs_info->inode_root;
+
+        key.objectid = objectid;
+        key.flags = 0;
+        key.offset = 0;
+        btrfs_set_key_type(&key, BTRFS_INODE_MAP_ITEM_KEY);
+        ret = btrfs_search_slot(trans, inode_root, &key, path, ins_len, cow);
+        return ret;
+}
+