Btrfs: Add a write ahead tree log to optimize synchronous operations
[pandora-kernel.git] / fs / btrfs / root-tree.c
index 13c3028..e3984f9 100644 (file)
-#include <linux/module.h>
+/*
+ * 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 "transaction.h"
 #include "disk-io.h"
 #include "print-tree.h"
 
+/*
+ * returns 0 on finding something, 1 if no more roots are there
+ * and < 0 on error
+ */
+int btrfs_search_root(struct btrfs_root *root, u64 search_start,
+                     u64 *found_objectid)
+{
+       struct btrfs_path *path;
+       struct btrfs_key search_key;
+       int ret;
+
+       root = root->fs_info->tree_root;
+       search_key.objectid = search_start;
+       search_key.type = (u8)-1;
+       search_key.offset = (u64)-1;
+
+       path = btrfs_alloc_path();
+       BUG_ON(!path);
+again:
+       ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+       if (ret < 0)
+               goto out;
+       if (ret == 0) {
+               ret = 1;
+               goto out;
+       }
+       if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+               ret = btrfs_next_leaf(root, path);
+               if (ret)
+                       goto out;
+       }
+       btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
+       if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
+               search_key.offset++;
+               btrfs_release_path(root, path);
+               goto again;
+       }
+       ret = 0;
+       *found_objectid = search_key.objectid;
+
+out:
+       btrfs_free_path(path);
+       return ret;
+}
+
 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
                        struct btrfs_root_item *item, struct btrfs_key *key)
 {
        struct btrfs_path *path;
        struct btrfs_key search_key;
-       struct btrfs_leaf *l;
+       struct btrfs_key found_key;
+       struct extent_buffer *l;
        int ret;
        int slot;
 
        search_key.objectid = objectid;
-       search_key.flags = (u32)-1;
-       search_key.offset = (u32)-1;
+       search_key.type = (u8)-1;
+       search_key.offset = (u64)-1;
 
        path = btrfs_alloc_path();
        BUG_ON(!path);
-       btrfs_init_path(path);
        ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
        if (ret < 0)
                goto out;
+
        BUG_ON(ret == 0);
-       l = btrfs_buffer_leaf(path->nodes[0]);
+       l = path->nodes[0];
        BUG_ON(path->slots[0] == 0);
        slot = path->slots[0] - 1;
-       if (btrfs_disk_key_objectid(&l->items[slot].key) != objectid) {
+       btrfs_item_key_to_cpu(l, &found_key, slot);
+       if (found_key.objectid != objectid) {
                ret = 1;
                goto out;
        }
-       memcpy(item, btrfs_item_ptr(l, slot, struct btrfs_root_item),
-               sizeof(*item));
-       btrfs_disk_key_to_cpu(key, &l->items[slot].key);
+       read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
+                          sizeof(*item));
+       memcpy(key, &found_key, sizeof(found_key));
        ret = 0;
 out:
-       btrfs_release_path(root, path);
        btrfs_free_path(path);
        return ret;
 }
@@ -45,22 +109,28 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
                      *item)
 {
        struct btrfs_path *path;
-       struct btrfs_leaf *l;
+       struct extent_buffer *l;
        int ret;
        int slot;
-       struct btrfs_root_item *update_item;
+       unsigned long ptr;
 
        path = btrfs_alloc_path();
        BUG_ON(!path);
-       btrfs_init_path(path);
        ret = btrfs_search_slot(trans, root, key, path, 0, 1);
        if (ret < 0)
                goto out;
-       BUG_ON(ret != 0);
-       l = btrfs_buffer_leaf(path->nodes[0]);
+
+       if (ret != 0) {
+               btrfs_print_leaf(root, path->nodes[0]);
+               printk("unable to update root key %Lu %u %Lu\n",
+                      key->objectid, key->type, key->offset);
+               BUG_ON(1);
+       }
+
+       l = path->nodes[0];
        slot = path->slots[0];
-       update_item = btrfs_item_ptr(l, slot, struct btrfs_root_item);
-       btrfs_memcpy(root, l, update_item, item, sizeof(*item));
+       ptr = btrfs_item_ptr_offset(l, slot);
+       write_extent_buffer(l, item, ptr, sizeof(*item));
        btrfs_mark_buffer_dirty(path->nodes[0]);
 out:
        btrfs_release_path(root, path);
@@ -74,7 +144,83 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
 {
        int ret;
        ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
-       BUG_ON(ret);
+       return ret;
+}
+
+int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
+                         struct btrfs_root *latest)
+{
+       struct btrfs_root *dead_root;
+       struct btrfs_item *item;
+       struct btrfs_root_item *ri;
+       struct btrfs_key key;
+       struct btrfs_key found_key;
+       struct btrfs_path *path;
+       int ret;
+       u32 nritems;
+       struct extent_buffer *leaf;
+       int slot;
+
+       key.objectid = objectid;
+       btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+       key.offset = 0;
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+again:
+       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       if (ret < 0)
+               goto err;
+       while(1) {
+               leaf = path->nodes[0];
+               nritems = btrfs_header_nritems(leaf);
+               slot = path->slots[0];
+               if (slot >= nritems) {
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret)
+                               break;
+                       leaf = path->nodes[0];
+                       nritems = btrfs_header_nritems(leaf);
+                       slot = path->slots[0];
+               }
+               item = btrfs_item_nr(leaf, slot);
+               btrfs_item_key_to_cpu(leaf, &key, slot);
+               if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
+                       goto next;
+
+               if (key.objectid < objectid)
+                       goto next;
+
+               if (key.objectid > objectid)
+                       break;
+
+               ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
+               if (btrfs_disk_root_refs(leaf, ri) != 0)
+                       goto next;
+
+               memcpy(&found_key, &key, sizeof(key));
+               key.offset++;
+               btrfs_release_path(root, path);
+               dead_root =
+                       btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
+                                                   &found_key);
+               if (IS_ERR(dead_root)) {
+                       ret = PTR_ERR(dead_root);
+                       goto err;
+               }
+
+               ret = btrfs_add_dead_root(dead_root, latest);
+               if (ret)
+                       goto err;
+               goto again;
+next:
+               slot++;
+               path->slots[0]++;
+       }
+       ret = 0;
+err:
+       btrfs_free_path(path);
        return ret;
 }
 
@@ -85,26 +231,25 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
        int ret;
        u32 refs;
        struct btrfs_root_item *ri;
+       struct extent_buffer *leaf;
 
        path = btrfs_alloc_path();
        BUG_ON(!path);
-       btrfs_init_path(path);
        ret = btrfs_search_slot(trans, root, key, path, -1, 1);
        if (ret < 0)
                goto out;
-       BUG_ON(ret != 0);
-       ri = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
-                           path->slots[0], struct btrfs_root_item);
-
-       refs = btrfs_root_refs(ri);
-       BUG_ON(refs == 0);
-       if (refs == 1) {
-               ret = btrfs_del_item(trans, root, path);
-       } else {
-               btrfs_set_root_refs(ri, refs - 1);
-               WARN_ON(1);
-               mark_buffer_dirty(path->nodes[0]);
+       if (ret) {
+btrfs_print_leaf(root, path->nodes[0]);
+printk("failed to del %Lu %u %Lu\n", key->objectid, key->type, key->offset);
+
        }
+       BUG_ON(ret != 0);
+       leaf = path->nodes[0];
+       ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
+
+       refs = btrfs_disk_root_refs(leaf, ri);
+       BUG_ON(refs != 0);
+       ret = btrfs_del_item(trans, root, path);
 out:
        btrfs_release_path(root, path);
        btrfs_free_path(path);