1 files changed, 144 insertions, 0 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
new file mode 100644
index 000000000000..2aa79873eb46
--- /dev/null
+++ b/fs/btrfs/inode-map.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+
+int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
+{
+        struct btrfs_path *path;
+        int ret;
+        struct extent_buffer *l;
+        struct btrfs_key search_key;
+        struct btrfs_key found_key;
+        int slot;
+
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+
+        search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
+        search_key.type = -1;
+        search_key.offset = (u64)-1;
+        ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+        if (ret < 0)
+                goto error;
+        BUG_ON(ret == 0);
+        if (path->slots[0] > 0) {
+                slot = path->slots[0] - 1;
+                l = path->nodes[0];
+                btrfs_item_key_to_cpu(l, &found_key, slot);
+                *objectid = found_key.objectid;
+        } else {
+                *objectid = BTRFS_FIRST_FREE_OBJECTID;
+        }
+        ret = 0;
+error:
+        btrfs_free_path(path);
+        return ret;
+}
+
+/*
+ * walks the btree of allocated inodes and find a hole.
+ */
+int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
+                             struct btrfs_root *root,
+                             u64 dirid, u64 *objectid)
+{
+        struct btrfs_path *path;
+        struct btrfs_key key;
+        int ret;
+        int slot = 0;
+        u64 last_ino = 0;
+        int start_found;
+        struct extent_buffer *l;
+        struct btrfs_key search_key;
+        u64 search_start = dirid;
+
+        mutex_lock(&root->objectid_mutex);
+        if (root->last_inode_alloc >= BTRFS_FIRST_FREE_OBJECTID &&
+            root->last_inode_alloc < BTRFS_LAST_FREE_OBJECTID) {
+                *objectid = ++root->last_inode_alloc;
+                mutex_unlock(&root->objectid_mutex);
+                return 0;
+        }
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
+        search_key.objectid = search_start;
+        search_key.type = 0;
+        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;
+
+        while (1) {
+                l = path->nodes[0];
+                slot = path->slots[0];
+                if (slot >= btrfs_header_nritems(l)) {
+                        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_item_key_to_cpu(l, &key, slot);
+                if (key.objectid >= search_start) {
+                        if (start_found) {
+                                if (last_ino < search_start)
+                                        last_ino = search_start;
+                                if (key.objectid > last_ino) {
+                                        *objectid = last_ino;
+                                        goto found;
+                                }
+                        } else if (key.objectid > search_start) {
+                                *objectid = search_start;
+                                goto found;
+                        }
+                }
+                if (key.objectid >= BTRFS_LAST_FREE_OBJECTID)
+                        break;
+
+                start_found = 1;
+                last_ino = key.objectid + 1;
+                path->slots[0]++;
+        }
+        BUG_ON(1);
+found:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
+        BUG_ON(*objectid < search_start);
+        mutex_unlock(&root->objectid_mutex);
+        return 0;
+error:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
+        mutex_unlock(&root->objectid_mutex);
+        return ret;
+}