2 * inode_table.c - hard link detection
6 * Copyright (C) 2012, 2013, 2014 Eric Biggers
8 * This file is free software; you can redistribute it and/or modify it under
9 * the terms of the GNU Lesser General Public License as published by the Free
10 * Software Foundation; either version 3 of the License, or (at your option) any
13 * This file is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this file; if not, see http://www.gnu.org/licenses/.
26 #include "wimlib/dentry.h"
27 #include "wimlib/error.h"
28 #include "wimlib/inode.h"
29 #include "wimlib/inode_table.h"
30 #include "wimlib/list.h"
31 #include "wimlib/util.h"
33 /* Initialize a hash table for hard link detection. */
35 init_inode_table(struct wim_inode_table *table, size_t capacity)
37 table->array = CALLOC(capacity, sizeof(table->array[0]));
39 return WIMLIB_ERR_NOMEM;
40 table->num_entries = 0;
41 table->capacity = capacity;
42 INIT_LIST_HEAD(&table->extra_inodes);
46 /* Free the memory allocated by init_inode_table(). */
48 destroy_inode_table(struct wim_inode_table *table)
53 static struct wim_inode *
54 inode_table_get_inode(struct wim_inode_table *table, u64 ino, u64 devno)
57 struct wim_inode *inode;
58 struct hlist_node *cur;
60 /* Search for an existing inode having the same inode number and device
62 pos = hash_u64(hash_u64(ino) + hash_u64(devno)) % table->capacity;
63 hlist_for_each_entry(inode, cur, &table->array[pos], i_hlist) {
64 if (inode->i_ino == ino && inode->i_devno == devno) {
65 /* Found; use the existing inode. */
71 /* Create a new inode and insert it into the table. */
72 inode = new_timeless_inode();
75 inode->i_devno = devno;
76 hlist_add_head(&inode->i_hlist, &table->array[pos]);
83 * Allocate a new dentry, with hard link detection.
86 * The inode table being used for the current directory scan operation. It
87 * will contain the mapping from (ino, devno) pairs to inodes.
90 * The name to give the new dentry.
93 * The inode number of the file, read from the filesystem.
96 * The device number of the file, read from the filesystem. Proper setting
97 * of this parameter prevents cross-device hardlinks from being created.
98 * If this is not a problem (perhaps because the current directory scan
99 * operation is guaranteed to never traverse a filesystem boundary), then
100 * this parameter can just be a fixed value such as 0.
103 * If %true, the new dentry will not be hard linked to any existing inode,
104 * regardless of the values of @ino and @devno. If %false, normal hard
105 * link detection will be done.
108 * On success, a pointer to the new dentry will be returned in this
109 * location. If i_nlink of the dentry's inode is greater than 1, then this
110 * function created a hard link to an existing inode rather than creating a
113 * On success, returns 0. On failure, returns WIMLIB_ERR_NOMEM or an error code
114 * resulting from a failed string conversion.
117 inode_table_new_dentry(struct wim_inode_table *table, const tchar *name,
118 u64 ino, u64 devno, bool noshare,
119 struct wim_dentry **dentry_ret)
121 struct wim_dentry *dentry;
122 struct wim_inode *inode;
126 /* File that cannot be hardlinked--- Return a new inode with its
127 * inode and device numbers left at 0. */
128 ret = new_dentry_with_timeless_inode(name, &dentry);
131 list_add_tail(&dentry->d_inode->i_list, &table->extra_inodes);
133 /* File that can be hardlinked--- search the table for an
134 * existing inode matching the inode number and device;
135 * otherwise create a new inode. */
136 ret = new_dentry(name, &dentry);
139 inode = inode_table_get_inode(table, ino, devno);
142 return WIMLIB_ERR_NOMEM;
144 /* If using an existing inode, we need to gain a reference to
145 * each of its streams. */
146 if (inode->i_nlink > 1)
147 inode_ref_streams(inode);
148 dentry->d_inode = inode;
149 inode_add_dentry(dentry, inode);
151 *dentry_ret = dentry;
156 * Following the allocation of dentries with hard link detection using
157 * inode_table_new_dentry(), this function will assign consecutive inode numbers
158 * to the new set of inodes. It will also append the list of new inodes to the
159 * list @head, which must contain any inodes already existing in the WIM image.
162 inode_table_prepare_inode_list(struct wim_inode_table *table,
163 struct list_head *head)
165 struct wim_inode *inode, *tmp_inode;
166 struct hlist_node *cur, *tmp;
169 /* Re-assign inode numbers in the existing list to avoid duplicates. */
170 list_for_each_entry(inode, head, i_list)
171 inode->i_ino = cur_ino++;
173 /* Assign inode numbers to the new inodes and move them to the image's
175 for (size_t i = 0; i < table->capacity; i++) {
176 hlist_for_each_entry_safe(inode, cur, tmp, &table->array[i], i_hlist)
178 inode->i_ino = cur_ino++;
180 list_add_tail(&inode->i_list, head);
182 INIT_HLIST_HEAD(&table->array[i]);
184 list_for_each_entry_safe(inode, tmp_inode, &table->extra_inodes, i_list)
186 inode->i_ino = cur_ino++;
188 list_add_tail(&inode->i_list, head);
190 INIT_LIST_HEAD(&table->extra_inodes);
191 table->num_entries = 0;