return 0;
}
-struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
- struct btrfs_key *key)
+static struct btrfs_root *read_tree_root_path(struct btrfs_root *tree_root,
+ struct btrfs_path *path,
+ struct btrfs_key *key)
{
struct btrfs_root *root;
struct btrfs_fs_info *fs_info = tree_root->fs_info;
- struct btrfs_path *path;
u64 generation;
int ret;
int level;
- path = btrfs_alloc_path();
- if (!path)
- return ERR_PTR(-ENOMEM);
-
root = btrfs_alloc_root(fs_info, key->objectid, GFP_NOFS);
- if (!root) {
- ret = -ENOMEM;
- goto alloc_fail;
- }
+ if (!root)
+ return ERR_PTR(-ENOMEM);
ret = btrfs_find_root(tree_root, key, path,
&root->root_item, &root->root_key);
if (ret) {
if (ret > 0)
ret = -ENOENT;
- goto find_fail;
+ goto fail;
}
generation = btrfs_root_generation(&root->root_item);
if (IS_ERR(root->node)) {
ret = PTR_ERR(root->node);
root->node = NULL;
- goto find_fail;
+ goto fail;
} else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
ret = -EIO;
- goto find_fail;
+ goto fail;
}
root->commit_root = btrfs_root_node(root);
-out:
- btrfs_free_path(path);
return root;
-
-find_fail:
+fail:
btrfs_put_root(root);
-alloc_fail:
- root = ERR_PTR(ret);
- goto out;
+ return ERR_PTR(ret);
+}
+
+struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
+ struct btrfs_key *key)
+{
+ struct btrfs_root *root;
+ struct btrfs_path *path;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return ERR_PTR(-ENOMEM);
+ root = read_tree_root_path(tree_root, path, key);
+ btrfs_free_path(path);
+
+ return root;
}
/*
return root;
}
+static struct btrfs_root *btrfs_get_global_root(struct btrfs_fs_info *fs_info,
+ u64 objectid)
+{
+ if (objectid == BTRFS_ROOT_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->tree_root);
+ if (objectid == BTRFS_EXTENT_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->extent_root);
+ if (objectid == BTRFS_CHUNK_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->chunk_root);
+ if (objectid == BTRFS_DEV_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->dev_root);
+ if (objectid == BTRFS_CSUM_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->csum_root);
+ if (objectid == BTRFS_QUOTA_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->quota_root) ?
+ fs_info->quota_root : ERR_PTR(-ENOENT);
+ if (objectid == BTRFS_UUID_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->uuid_root) ?
+ fs_info->uuid_root : ERR_PTR(-ENOENT);
+ if (objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->free_space_root) ?
+ fs_info->free_space_root : ERR_PTR(-ENOENT);
+ return NULL;
+}
+
int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
struct btrfs_root *root)
{
struct btrfs_key key;
int ret;
- if (objectid == BTRFS_ROOT_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->tree_root);
- if (objectid == BTRFS_EXTENT_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->extent_root);
- if (objectid == BTRFS_CHUNK_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->chunk_root);
- if (objectid == BTRFS_DEV_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->dev_root);
- if (objectid == BTRFS_CSUM_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->csum_root);
- if (objectid == BTRFS_QUOTA_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->quota_root) ?
- fs_info->quota_root : ERR_PTR(-ENOENT);
- if (objectid == BTRFS_UUID_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->uuid_root) ?
- fs_info->uuid_root : ERR_PTR(-ENOENT);
- if (objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
- return btrfs_grab_root(fs_info->free_space_root) ?
- fs_info->free_space_root : ERR_PTR(-ENOENT);
+ root = btrfs_get_global_root(fs_info, objectid);
+ if (root)
+ return root;
again:
root = btrfs_lookup_fs_root(fs_info, objectid);
if (root) {
return btrfs_get_root_ref(fs_info, objectid, anon_dev, true);
}
+/*
+ * btrfs_get_fs_root_commit_root - return a root for the given objectid
+ * @fs_info: the fs_info
+ * @objectid: the objectid we need to lookup
+ *
+ * This is exclusively used for backref walking, and exists specifically because
+ * of how qgroups does lookups. Qgroups will do a backref lookup at delayed ref
+ * creation time, which means we may have to read the tree_root in order to look
+ * up a fs root that is not in memory. If the root is not in memory we will
+ * read the tree root commit root and look up the fs root from there. This is a
+ * temporary root, it will not be inserted into the radix tree as it doesn't
+ * have the most uptodate information, it'll simply be discarded once the
+ * backref code is finished using the root.
+ */
+struct btrfs_root *btrfs_get_fs_root_commit_root(struct btrfs_fs_info *fs_info,
+ struct btrfs_path *path,
+ u64 objectid)
+{
+ struct btrfs_root *root;
+ struct btrfs_key key;
+
+ ASSERT(path->search_commit_root && path->skip_locking);
+
+ /*
+ * This can return -ENOENT if we ask for a root that doesn't exist, but
+ * since this is called via the backref walking code we won't be looking
+ * up a root that doesn't exist, unless there's corruption. So if root
+ * != NULL just return it.
+ */
+ root = btrfs_get_global_root(fs_info, objectid);
+ if (root)
+ return root;
+
+ root = btrfs_lookup_fs_root(fs_info, objectid);
+ if (root)
+ return root;
+
+ key.objectid = objectid;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+ root = read_tree_root_path(fs_info->tree_root, path, &key);
+ btrfs_release_path(path);
+
+ return root;
+}
+
/*
* called by the kthread helper functions to finally call the bio end_io
* functions. This is where read checksum verification actually happens
git.samba.org / sfrench / cifs-2.6.git / blobdiff