diff options
Diffstat (limited to 'fs/btrfs/uuid-tree.c')
| -rw-r--r-- | fs/btrfs/uuid-tree.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/fs/btrfs/uuid-tree.c b/fs/btrfs/uuid-tree.c new file mode 100644 index 000000000000..04a04fa0f7c4 --- /dev/null +++ b/fs/btrfs/uuid-tree.c @@ -0,0 +1,235 @@ +/* + * Copyright (C) STRATO AG 2013. 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 <linux/uuid.h> +#include <asm/unaligned.h> +#include "ctree.h" +#include "transaction.h" +#include "disk-io.h" +#include "print-tree.h" + + +static void btrfs_uuid_to_key(u8 *uuid, u8 type, struct btrfs_key *key) +{ + key->type = type; + key->objectid = get_unaligned_le64(uuid); + key->offset = get_unaligned_le64(uuid + sizeof(u64)); +} + +/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */ +static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid, + u8 type, u64 subid) +{ + int ret; + struct btrfs_path *path = NULL; + struct extent_buffer *eb; + int slot; + u32 item_size; + unsigned long offset; + struct btrfs_key key; + + if (WARN_ON_ONCE(!uuid_root)) { + ret = -ENOENT; + goto out; + } + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + btrfs_uuid_to_key(uuid, type, &key); + ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0); + if (ret < 0) { + goto out; + } else if (ret > 0) { + ret = -ENOENT; + goto out; + } + + eb = path->nodes[0]; + slot = path->slots[0]; + item_size = btrfs_item_size_nr(eb, slot); + offset = btrfs_item_ptr_offset(eb, slot); + ret = -ENOENT; + + if (!IS_ALIGNED(item_size, sizeof(u64))) { + pr_warn("btrfs: uuid item with illegal size %lu!\n", + (unsigned long)item_size); + goto out; + } + while (item_size) { + __le64 data; + + read_extent_buffer(eb, &data, offset, sizeof(data)); + if (le64_to_cpu(data) == subid) { + ret = 0; + break; + } + offset += sizeof(data); + item_size -= sizeof(data); + } + +out: + btrfs_free_path(path); + return ret; +} + +int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, + struct btrfs_root *uuid_root, u8 *uuid, u8 type, + u64 subid_cpu) +{ + int ret; + struct btrfs_path *path = NULL; + struct btrfs_key key; + struct extent_buffer *eb; + int slot; + unsigned long offset; + __le64 subid_le; + + ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu); + if (ret != -ENOENT) + return ret; + + if (WARN_ON_ONCE(!uuid_root)) { + ret = -EINVAL; + goto out; + } + + btrfs_uuid_to_key(uuid, type, &key); + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + ret = btrfs_insert_empty_item(trans, uuid_root, path, &key, + sizeof(subid_le)); + if (ret >= 0) { + /* Add an item for the type for the first time */ + eb = path->nodes[0]; + slot = path->slots[0]; + offset = btrfs_item_ptr_offset(eb, slot); + } else if (ret == -EEXIST) { + /* + * An item with that type already exists. + * Extend the item and store the new subid at the end. + */ + btrfs_extend_item(uuid_root, path, sizeof(subid_le)); + eb = path->nodes[0]; + slot = path->slots[0]; + offset = btrfs_item_ptr_offset(eb, slot); + offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le); + } else if (ret < 0) { + pr_warn("btrfs: insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!\n", + ret, (unsigned long long)key.objectid, + (unsigned long long)key.offset, type); + goto out; + } + + ret = 0; + subid_le = cpu_to_le64(subid_cpu); + write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le)); + btrfs_mark_buffer_dirty(eb); + +out: + btrfs_free_path(path); + return ret; +} + +int btrfs_uuid_tree_rem(struct btrfs_trans_handle *trans, + struct btrfs_root *uuid_root, u8 *uuid, u8 type, + u64 subid) +{ + int ret; + struct btrfs_path *path = NULL; + struct btrfs_key key; + struct extent_buffer *eb; + int slot; + unsigned long offset; + u32 item_size; + unsigned long move_dst; + unsigned long move_src; + unsigned long move_len; + + if (WARN_ON_ONCE(!uuid_root)) { + ret = -EINVAL; + goto out; + } + + btrfs_uuid_to_key(uuid, type, &key); + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1); + if (ret < 0) { + pr_warn("btrfs: error %d while searching for uuid item!\n", + ret); + goto out; + } + if (ret > 0) { + ret = -ENOENT; + goto out; + } + + eb = path->nodes[0]; + slot = path->slots[0]; + offset = btrfs_item_ptr_offset(eb, slot); + item_size = btrfs_item_size_nr(eb, slot); + if (!IS_ALIGNED(item_size, sizeof(u64))) { + pr_warn("btrfs: uuid item with illegal size %lu!\n", + (unsigned long)item_size); + ret = -ENOENT; + goto out; + } + while (item_size) { + __le64 read_subid; + + read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid)); + if (le64_to_cpu(read_subid) == subid) + break; + offset += sizeof(read_subid); + item_size -= sizeof(read_subid); + } + + if (!item_size) { + ret = -ENOENT; + goto out; + } + + item_size = btrfs_item_size_nr(eb, slot); + if (item_size == sizeof(subid)) { + ret = btrfs_del_item(trans, uuid_root, path); + goto out; + } + + move_dst = offset; + move_src = offset + sizeof(subid); + move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot)); + memmove_extent_buffer(eb, move_dst, move_src, move_len); + btrfs_truncate_item(uuid_root, path, item_size - sizeof(subid), 1); + +out: + btrfs_free_path(path); + return ret; +} |