1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include "ctree.h"
20 #include "disk-io.h"
21 #include "transaction.h"
22 #include "print-tree.h"
23
find_name_in_backref(struct btrfs_path * path,const char * name,int name_len,struct btrfs_inode_ref ** ref_ret)24 static int find_name_in_backref(struct btrfs_path *path, const char *name,
25 int name_len, struct btrfs_inode_ref **ref_ret)
26 {
27 struct extent_buffer *leaf;
28 struct btrfs_inode_ref *ref;
29 unsigned long ptr;
30 unsigned long name_ptr;
31 u32 item_size;
32 u32 cur_offset = 0;
33 int len;
34
35 leaf = path->nodes[0];
36 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
37 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
38 while (cur_offset < item_size) {
39 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
40 len = btrfs_inode_ref_name_len(leaf, ref);
41 name_ptr = (unsigned long)(ref + 1);
42 cur_offset += len + sizeof(*ref);
43 if (len != name_len)
44 continue;
45 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
46 *ref_ret = ref;
47 return 1;
48 }
49 }
50 return 0;
51 }
52
53 struct btrfs_inode_ref *
btrfs_lookup_inode_ref(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,const char * name,int name_len,u64 inode_objectid,u64 ref_objectid,int mod)54 btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
55 struct btrfs_root *root,
56 struct btrfs_path *path,
57 const char *name, int name_len,
58 u64 inode_objectid, u64 ref_objectid, int mod)
59 {
60 struct btrfs_key key;
61 struct btrfs_inode_ref *ref;
62 int ins_len = mod < 0 ? -1 : 0;
63 int cow = mod != 0;
64 int ret;
65
66 key.objectid = inode_objectid;
67 key.type = BTRFS_INODE_REF_KEY;
68 key.offset = ref_objectid;
69
70 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
71 if (ret < 0)
72 return ERR_PTR(ret);
73 if (ret > 0)
74 return NULL;
75 if (!find_name_in_backref(path, name, name_len, &ref))
76 return NULL;
77 return ref;
78 }
79
btrfs_del_inode_ref(struct btrfs_trans_handle * trans,struct btrfs_root * root,const char * name,int name_len,u64 inode_objectid,u64 ref_objectid,u64 * index)80 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
81 struct btrfs_root *root,
82 const char *name, int name_len,
83 u64 inode_objectid, u64 ref_objectid, u64 *index)
84 {
85 struct btrfs_path *path;
86 struct btrfs_key key;
87 struct btrfs_inode_ref *ref;
88 struct extent_buffer *leaf;
89 unsigned long ptr;
90 unsigned long item_start;
91 u32 item_size;
92 u32 sub_item_len;
93 int ret;
94 int del_len = name_len + sizeof(*ref);
95
96 key.objectid = inode_objectid;
97 key.offset = ref_objectid;
98 btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
99
100 path = btrfs_alloc_path();
101 if (!path)
102 return -ENOMEM;
103
104 path->leave_spinning = 1;
105
106 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
107 if (ret > 0) {
108 ret = -ENOENT;
109 goto out;
110 } else if (ret < 0) {
111 goto out;
112 }
113 if (!find_name_in_backref(path, name, name_len, &ref)) {
114 ret = -ENOENT;
115 goto out;
116 }
117 leaf = path->nodes[0];
118 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
119
120 if (index)
121 *index = btrfs_inode_ref_index(leaf, ref);
122
123 if (del_len == item_size) {
124 ret = btrfs_del_item(trans, root, path);
125 goto out;
126 }
127 ptr = (unsigned long)ref;
128 sub_item_len = name_len + sizeof(*ref);
129 item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
130 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
131 item_size - (ptr + sub_item_len - item_start));
132 btrfs_truncate_item(trans, root, path,
133 item_size - sub_item_len, 1);
134 out:
135 btrfs_free_path(path);
136 return ret;
137 }
138
139 /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
btrfs_insert_inode_ref(struct btrfs_trans_handle * trans,struct btrfs_root * root,const char * name,int name_len,u64 inode_objectid,u64 ref_objectid,u64 index)140 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
141 struct btrfs_root *root,
142 const char *name, int name_len,
143 u64 inode_objectid, u64 ref_objectid, u64 index)
144 {
145 struct btrfs_path *path;
146 struct btrfs_key key;
147 struct btrfs_inode_ref *ref;
148 unsigned long ptr;
149 int ret;
150 int ins_len = name_len + sizeof(*ref);
151
152 key.objectid = inode_objectid;
153 key.offset = ref_objectid;
154 btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
155
156 path = btrfs_alloc_path();
157 if (!path)
158 return -ENOMEM;
159
160 path->leave_spinning = 1;
161 ret = btrfs_insert_empty_item(trans, root, path, &key,
162 ins_len);
163 if (ret == -EEXIST) {
164 u32 old_size;
165
166 if (find_name_in_backref(path, name, name_len, &ref))
167 goto out;
168
169 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
170 btrfs_extend_item(trans, root, path, ins_len);
171 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
172 struct btrfs_inode_ref);
173 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
174 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
175 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
176 ptr = (unsigned long)(ref + 1);
177 ret = 0;
178 } else if (ret < 0) {
179 if (ret == -EOVERFLOW)
180 ret = -EMLINK;
181 goto out;
182 } else {
183 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
184 struct btrfs_inode_ref);
185 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
186 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
187 ptr = (unsigned long)(ref + 1);
188 }
189 write_extent_buffer(path->nodes[0], name, ptr, name_len);
190 btrfs_mark_buffer_dirty(path->nodes[0]);
191
192 out:
193 btrfs_free_path(path);
194 return ret;
195 }
196
btrfs_insert_empty_inode(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 objectid)197 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
198 struct btrfs_root *root,
199 struct btrfs_path *path, u64 objectid)
200 {
201 struct btrfs_key key;
202 int ret;
203 key.objectid = objectid;
204 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
205 key.offset = 0;
206
207 ret = btrfs_insert_empty_item(trans, root, path, &key,
208 sizeof(struct btrfs_inode_item));
209 return ret;
210 }
211
btrfs_lookup_inode(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,struct btrfs_key * location,int mod)212 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
213 *root, struct btrfs_path *path,
214 struct btrfs_key *location, int mod)
215 {
216 int ins_len = mod < 0 ? -1 : 0;
217 int cow = mod != 0;
218 int ret;
219 int slot;
220 struct extent_buffer *leaf;
221 struct btrfs_key found_key;
222
223 ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
224 if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
225 location->offset == (u64)-1 && path->slots[0] != 0) {
226 slot = path->slots[0] - 1;
227 leaf = path->nodes[0];
228 btrfs_item_key_to_cpu(leaf, &found_key, slot);
229 if (found_key.objectid == location->objectid &&
230 btrfs_key_type(&found_key) == btrfs_key_type(location)) {
231 path->slots[0]--;
232 return 0;
233 }
234 }
235 return ret;
236 }
237