diff options
Diffstat (limited to 'fs/btrfs/dir-item.c')
| -rw-r--r-- | fs/btrfs/dir-item.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c new file mode 100644 index 00000000000..926a0b287a7 --- /dev/null +++ b/fs/btrfs/dir-item.c @@ -0,0 +1,386 @@ +/* + * 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 "hash.h" +#include "transaction.h" + +/* + * insert a name into a directory, doing overflow properly if there is a hash + * collision. data_size indicates how big the item inserted should be. On + * success a struct btrfs_dir_item pointer is returned, otherwise it is + * an ERR_PTR. + * + * The name is not copied into the dir item, you have to do that yourself. + */ +static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle + *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct btrfs_key *cpu_key, + u32 data_size, + const char *name, + int name_len) +{ + int ret; + char *ptr; + struct btrfs_item *item; + struct extent_buffer *leaf; + + ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); + if (ret == -EEXIST) { + struct btrfs_dir_item *di; + di = btrfs_match_dir_item_name(root, path, name, name_len); + if (di) + return ERR_PTR(-EEXIST); + ret = btrfs_extend_item(trans, root, path, data_size); + WARN_ON(ret > 0); + } + if (ret < 0) + return ERR_PTR(ret); + WARN_ON(ret > 0); + leaf = path->nodes[0]; + item = btrfs_item_nr(leaf, path->slots[0]); + ptr = btrfs_item_ptr(leaf, path->slots[0], char); + BUG_ON(data_size > btrfs_item_size(leaf, item)); + ptr += btrfs_item_size(leaf, item) - data_size; + return (struct btrfs_dir_item *)ptr; +} + +/* + * xattrs work a lot like directories, this inserts an xattr item + * into the tree + */ +int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, const char *name, + u16 name_len, const void *data, u16 data_len, + u64 dir) +{ + int ret = 0; + struct btrfs_path *path; + struct btrfs_dir_item *dir_item; + unsigned long name_ptr, data_ptr; + struct btrfs_key key, location; + struct btrfs_disk_key disk_key; + struct extent_buffer *leaf; + u32 data_size; + + key.objectid = dir; + btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); + key.offset = btrfs_name_hash(name, name_len); + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + if (name_len + data_len + sizeof(struct btrfs_dir_item) > + BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item)) + return -ENOSPC; + + data_size = sizeof(*dir_item) + name_len + data_len; + dir_item = insert_with_overflow(trans, root, path, &key, data_size, + name, name_len); + /* + * FIXME: at some point we should handle xattr's that are larger than + * what we can fit in our leaf. We set location to NULL b/c we arent + * pointing at anything else, that will change if we store the xattr + * data in a separate inode. + */ + BUG_ON(IS_ERR(dir_item)); + memset(&location, 0, sizeof(location)); + + leaf = path->nodes[0]; + btrfs_cpu_key_to_disk(&disk_key, &location); + btrfs_set_dir_item_key(leaf, dir_item, &disk_key); + btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR); + btrfs_set_dir_name_len(leaf, dir_item, name_len); + btrfs_set_dir_transid(leaf, dir_item, trans->transid); + btrfs_set_dir_data_len(leaf, dir_item, data_len); + name_ptr = (unsigned long)(dir_item + 1); + data_ptr = (unsigned long)((char *)name_ptr + name_len); + + write_extent_buffer(leaf, name, name_ptr, name_len); + write_extent_buffer(leaf, data, data_ptr, data_len); + btrfs_mark_buffer_dirty(path->nodes[0]); + + btrfs_free_path(path); + return ret; +} + +/* + * insert a directory item in the tree, doing all the magic for + * both indexes. 'dir' indicates which objectid to insert it into, + * 'location' is the key to stuff into the directory item, 'type' is the + * type of the inode we're pointing to, and 'index' is the sequence number + * to use for the second index (if one is created). + */ +int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root + *root, const char *name, int name_len, u64 dir, + struct btrfs_key *location, u8 type, u64 index) +{ + int ret = 0; + int ret2 = 0; + struct btrfs_path *path; + struct btrfs_dir_item *dir_item; + struct extent_buffer *leaf; + unsigned long name_ptr; + struct btrfs_key key; + struct btrfs_disk_key disk_key; + u32 data_size; + + key.objectid = dir; + btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY); + key.offset = btrfs_name_hash(name, name_len); + path = btrfs_alloc_path(); + data_size = sizeof(*dir_item) + name_len; + dir_item = insert_with_overflow(trans, root, path, &key, data_size, + name, name_len); + if (IS_ERR(dir_item)) { + ret = PTR_ERR(dir_item); + if (ret == -EEXIST) + goto second_insert; + goto out; + } + + leaf = path->nodes[0]; + btrfs_cpu_key_to_disk(&disk_key, location); + btrfs_set_dir_item_key(leaf, dir_item, &disk_key); + btrfs_set_dir_type(leaf, dir_item, type); + btrfs_set_dir_data_len(leaf, dir_item, 0); + btrfs_set_dir_name_len(leaf, dir_item, name_len); + btrfs_set_dir_transid(leaf, dir_item, trans->transid); + name_ptr = (unsigned long)(dir_item + 1); + + write_extent_buffer(leaf, name, name_ptr, name_len); + btrfs_mark_buffer_dirty(leaf); + +second_insert: + /* FIXME, use some real flag for selecting the extra index */ + if (root == root->fs_info->tree_root) { + ret = 0; + goto out; + } + btrfs_release_path(root, path); + + btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY); + key.offset = index; + dir_item = insert_with_overflow(trans, root, path, &key, data_size, + name, name_len); + if (IS_ERR(dir_item)) { + ret2 = PTR_ERR(dir_item); + goto out; + } + leaf = path->nodes[0]; + btrfs_cpu_key_to_disk(&disk_key, location); + btrfs_set_dir_item_key(leaf, dir_item, &disk_key); + btrfs_set_dir_type(leaf, dir_item, type); + btrfs_set_dir_data_len(leaf, dir_item, 0); + btrfs_set_dir_name_len(leaf, dir_item, name_len); + btrfs_set_dir_transid(leaf, dir_item, trans->transid); + name_ptr = (unsigned long)(dir_item + 1); + write_extent_buffer(leaf, name, name_ptr, name_len); + btrfs_mark_buffer_dirty(leaf); +out: + btrfs_free_path(path); + if (ret) + return ret; + if (ret2) + return ret2; + return 0; +} + +/* + * lookup a directory item based on name. 'dir' is the objectid + * we're searching in, and 'mod' tells us if you plan on deleting the + * item (use mod < 0) or changing the options (use mod > 0) + */ +struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, u64 dir, + const char *name, int name_len, + int mod) +{ + int ret; + struct btrfs_key key; + int ins_len = mod < 0 ? -1 : 0; + int cow = mod != 0; + struct btrfs_key found_key; + struct extent_buffer *leaf; + + key.objectid = dir; + btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY); + + key.offset = btrfs_name_hash(name, name_len); + + ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) { + if (path->slots[0] == 0) + return NULL; + path->slots[0]--; + } + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + + if (found_key.objectid != dir || + btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY || + found_key.offset != key.offset) + return NULL; + + return btrfs_match_dir_item_name(root, path, name, name_len); +} + +/* + * lookup a directory item based on index. 'dir' is the objectid + * we're searching in, and 'mod' tells us if you plan on deleting the + * item (use mod < 0) or changing the options (use mod > 0) + * + * The name is used to make sure the index really points to the name you were + * looking for. + */ +struct btrfs_dir_item * +btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, u64 dir, + u64 objectid, const char *name, int name_len, + int mod) +{ + int ret; + struct btrfs_key key; + int ins_len = mod < 0 ? -1 : 0; + int cow = mod != 0; + + key.objectid = dir; + btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY); + key.offset = objectid; + + ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) + return ERR_PTR(-ENOENT); + return btrfs_match_dir_item_name(root, path, name, name_len); +} + +struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, u64 dir, + const char *name, u16 name_len, + int mod) +{ + int ret; + struct btrfs_key key; + int ins_len = mod < 0 ? -1 : 0; + int cow = mod != 0; + struct btrfs_key found_key; + struct extent_buffer *leaf; + + key.objectid = dir; + btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); + key.offset = btrfs_name_hash(name, name_len); + ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow); + if (ret < 0) + return ERR_PTR(ret); + if (ret > 0) { + if (path->slots[0] == 0) + return NULL; + path->slots[0]--; + } + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + + if (found_key.objectid != dir || + btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY || + found_key.offset != key.offset) + return NULL; + + return btrfs_match_dir_item_name(root, path, name, name_len); +} + +/* + * helper function to look at the directory item pointed to by 'path' + * this walks through all the entries in a dir item and finds one + * for a specific name. + */ +struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root, + struct btrfs_path *path, + const char *name, int name_len) +{ + struct btrfs_dir_item *dir_item; + unsigned long name_ptr; + u32 total_len; + u32 cur = 0; + u32 this_len; + struct extent_buffer *leaf; + + leaf = path->nodes[0]; + dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item); + total_len = btrfs_item_size_nr(leaf, path->slots[0]); + while (cur < total_len) { + this_len = sizeof(*dir_item) + + btrfs_dir_name_len(leaf, dir_item) + + btrfs_dir_data_len(leaf, dir_item); + name_ptr = (unsigned long)(dir_item + 1); + + if (btrfs_dir_name_len(leaf, dir_item) == name_len && + memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) + return dir_item; + + cur += this_len; + dir_item = (struct btrfs_dir_item *)((char *)dir_item + + this_len); + } + return NULL; +} + +/* + * given a pointer into a directory item, delete it. This + * handles items that have more than one entry in them. + */ +int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct btrfs_dir_item *di) +{ + + struct extent_buffer *leaf; + u32 sub_item_len; + u32 item_len; + int ret = 0; + + leaf = path->nodes[0]; + sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) + + btrfs_dir_data_len(leaf, di); + item_len = btrfs_item_size_nr(leaf, path->slots[0]); + if (sub_item_len == item_len) { + ret = btrfs_del_item(trans, root, path); + } else { + /* MARKER */ + unsigned long ptr = (unsigned long)di; + unsigned long start; + + start = btrfs_item_ptr_offset(leaf, path->slots[0]); + memmove_extent_buffer(leaf, ptr, ptr + sub_item_len, + item_len - (ptr + sub_item_len - start)); + ret = btrfs_truncate_item(trans, root, path, + item_len - sub_item_len, 1); + } + return 0; +} |