![Jeff Mahoney](/assets/img/avatar_default.png)
btrfs currently handles most errors with BUG_ON. This patch is a work-in- progress but aims to handle most errors other than internal logic errors and ENOMEM more gracefully. This iteration prevents most crashes but can run into lockups with the page lock on occasion when the timing "works out." Signed-off-by: Jeff Mahoney <jeffm@suse.com>
236 lines
6.4 KiB
C
236 lines
6.4 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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static int find_name_in_backref(struct btrfs_path *path, const char *name,
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int name_len, struct btrfs_inode_ref **ref_ret)
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{
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struct extent_buffer *leaf;
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struct btrfs_inode_ref *ref;
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unsigned long ptr;
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unsigned long name_ptr;
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u32 item_size;
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u32 cur_offset = 0;
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int len;
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leaf = path->nodes[0];
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item_size = btrfs_item_size_nr(leaf, path->slots[0]);
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ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
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while (cur_offset < item_size) {
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ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
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len = btrfs_inode_ref_name_len(leaf, ref);
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name_ptr = (unsigned long)(ref + 1);
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cur_offset += len + sizeof(*ref);
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if (len != name_len)
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continue;
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if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
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*ref_ret = ref;
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return 1;
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}
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}
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return 0;
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}
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struct btrfs_inode_ref *
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btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, int mod)
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{
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struct btrfs_key key;
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struct btrfs_inode_ref *ref;
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int ins_len = mod < 0 ? -1 : 0;
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int cow = mod != 0;
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int ret;
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key.objectid = inode_objectid;
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key.type = BTRFS_INODE_REF_KEY;
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key.offset = ref_objectid;
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ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
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if (ret < 0)
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return ERR_PTR(ret);
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if (ret > 0)
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return NULL;
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if (!find_name_in_backref(path, name, name_len, &ref))
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return NULL;
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return ref;
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}
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int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, u64 *index)
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{
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_inode_ref *ref;
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struct extent_buffer *leaf;
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unsigned long ptr;
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unsigned long item_start;
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u32 item_size;
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u32 sub_item_len;
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int ret;
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int del_len = name_len + sizeof(*ref);
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key.objectid = inode_objectid;
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key.offset = ref_objectid;
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btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->leave_spinning = 1;
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ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
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if (ret > 0) {
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ret = -ENOENT;
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goto out;
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} else if (ret < 0) {
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goto out;
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}
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if (!find_name_in_backref(path, name, name_len, &ref)) {
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ret = -ENOENT;
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goto out;
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}
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leaf = path->nodes[0];
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item_size = btrfs_item_size_nr(leaf, path->slots[0]);
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if (index)
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*index = btrfs_inode_ref_index(leaf, ref);
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if (del_len == item_size) {
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ret = btrfs_del_item(trans, root, path);
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goto out;
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}
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ptr = (unsigned long)ref;
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sub_item_len = name_len + sizeof(*ref);
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item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
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memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
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item_size - (ptr + sub_item_len - item_start));
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btrfs_truncate_item(trans, root, path,
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item_size - sub_item_len, 1);
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out:
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btrfs_free_path(path);
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return ret;
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}
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/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
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int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const char *name, int name_len,
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u64 inode_objectid, u64 ref_objectid, u64 index)
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{
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_inode_ref *ref;
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unsigned long ptr;
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int ret;
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int ins_len = name_len + sizeof(*ref);
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key.objectid = inode_objectid;
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key.offset = ref_objectid;
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btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->leave_spinning = 1;
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ret = btrfs_insert_empty_item(trans, root, path, &key,
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ins_len);
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if (ret == -EEXIST) {
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u32 old_size;
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if (find_name_in_backref(path, name, name_len, &ref))
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goto out;
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old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
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btrfs_extend_item(trans, root, path, ins_len);
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ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
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struct btrfs_inode_ref);
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ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
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btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
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btrfs_set_inode_ref_index(path->nodes[0], ref, index);
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ptr = (unsigned long)(ref + 1);
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ret = 0;
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} else if (ret < 0) {
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if (ret == -EOVERFLOW)
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ret = -EMLINK;
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goto out;
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} else {
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ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
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struct btrfs_inode_ref);
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btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
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btrfs_set_inode_ref_index(path->nodes[0], ref, index);
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ptr = (unsigned long)(ref + 1);
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}
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write_extent_buffer(path->nodes[0], name, ptr, name_len);
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btrfs_mark_buffer_dirty(path->nodes[0]);
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out:
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, u64 objectid)
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{
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struct btrfs_key key;
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int ret;
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key.objectid = objectid;
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btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
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key.offset = 0;
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ret = btrfs_insert_empty_item(trans, root, path, &key,
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sizeof(struct btrfs_inode_item));
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return ret;
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}
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int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, struct btrfs_path *path,
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struct btrfs_key *location, int mod)
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{
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int ins_len = mod < 0 ? -1 : 0;
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int cow = mod != 0;
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int ret;
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int slot;
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struct extent_buffer *leaf;
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struct btrfs_key found_key;
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ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
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if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
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location->offset == (u64)-1 && path->slots[0] != 0) {
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slot = path->slots[0] - 1;
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leaf = path->nodes[0];
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btrfs_item_key_to_cpu(leaf, &found_key, slot);
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if (found_key.objectid == location->objectid &&
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btrfs_key_type(&found_key) == btrfs_key_type(location)) {
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path->slots[0]--;
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return 0;
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}
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}
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return ret;
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}
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