+/*
+ * hardlink.c
+ *
+ * Code to deal with hard links in WIMs. Essentially, the WIM dentries are put
+ * into a hash table indexed by the inode ID field, then for each hard
+ * inode, a linked list is made to connect the dentries.
+ */
+
+/*
+ * Copyright (C) 2012 Eric Biggers
+ *
+ * This file is part of wimlib, a library for working with WIM files.
+ *
+ * wimlib is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * wimlib 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 wimlib; if not, see http://www.gnu.org/licenses/.
+ */
+
#include "wimlib_internal.h"
#include "dentry.h"
#include "list.h"
#include "lookup_table.h"
-struct link_group {
- u64 link_group_id;
- struct link_group *next;
- struct list_head *dentry_list;
-};
+/* NULL NULL
+ * ^ ^
+ * dentry | |
+ * / \ ----------- -----------
+ * | dentry<---| struct | | struct |---> dentry
+ * \ / |inode| |inode|
+ * dentry ------------ ------------
+ * ^ ^
+ * | |
+ * | | dentry
+ * ----------- ----------- / \
+ * dentry<---| struct | | struct |---> dentry dentry
+ * / |inode| |inode| \ /
+ * dentry ------------ ------------ dentry
+ * ^ ^
+ * | |
+ * -----------------
+ * inode_table->array | idx 0 | idx 1 |
+ * -----------------
+ */
-struct link_group_table {
- struct link_group **array;
+/* Hash table to find inodes, identified by their inode ID.
+ * */
+struct inode_table {
+ /* Fields for the hash table */
+ struct hlist_head *array;
u64 num_entries;
u64 capacity;
-};
-#include <sys/mman.h>
+ /*
+ * Linked list of "extra" inodes. These may be:
+ *
+ * - inodes with link count 1, which are all allowed to have 0 for their
+ * inode number, meaning we cannot insert them into the hash table
+ * before calling assign_inode_numbers().
+ *
+ * - Groups we create ourselves by splitting a nominal inode due to
+ * inconsistencies in the dentries. These inodes will share a inode
+ * ID with some other inode until assign_inode_numbers() is called.
+ */
+ struct hlist_head extra_inodes;
+};
-struct link_group_table *new_link_group_table(u64 capacity)
+/* Returns pointer to a new inode table having the specified capacity */
+struct inode_table *new_inode_table(size_t capacity)
{
- return (struct link_group_table*)new_lookup_table(capacity);
+ struct inode_table *table;
+ struct hlist_head *array;
+
+ table = MALLOC(sizeof(struct inode_table));
+ if (!table)
+ goto err;
+ array = CALLOC(capacity, sizeof(array[0]));
+ if (!array) {
+ FREE(table);
+ goto err;
+ }
+ table->num_entries = 0;
+ table->capacity = capacity;
+ table->array = array;
+ INIT_HLIST_HEAD(&table->extra_inodes);
+ return table;
+err:
+ ERROR("Failed to allocate memory for inode table with capacity %zu",
+ capacity);
+ return NULL;
}
-/* Insert a dentry into the hard link group table based on its hard link group
+/*
+ * Insert a dentry into the inode table based on its inode
* ID.
*
- * If there is already a dentry in the table having the same hard link group ID,
- * we link the dentries together in a circular list.
+ * If there is already a dentry in the table having the same inode ID,
+ * and the inode ID is not 0, the dentry is added to the circular
+ * linked list for that inode.
*
- * If the hard link group ID is 0, this is a no-op and the dentry is not
- * inserted.
+ * If the inode ID is 0, this indicates a dentry that's in a hard link
+ * inode by itself (has a link count of 1). We can't insert it into the hash
+ * table itself because we don't know what inode numbers are available to
+ * give it (this could be kept track of but would be more difficult). Instead
+ * we keep a linked list of the single dentries, and assign them inode
+ * numbers later.
*/
-int link_group_table_insert(struct dentry *dentry, struct link_group_table *table)
+int inode_table_insert(struct dentry *dentry, void *__table)
{
+ struct inode_table *table = __table;
size_t pos;
- struct link_group *group;
+ struct inode *inode;
+ struct inode *d_inode = dentry->inode;
- if (dentry->hard_link == 0) {
- INIT_LIST_HEAD(&dentry->link_group_list);
- return 0;
- }
+ if (d_inode->ino == 0) {
- /* Try adding to existing hard link group */
- pos = dentry->hard_link % table->capacity;
- group = table->array[pos];
- while (group) {
- if (group->link_group_id == dentry->hard_link) {
- list_add(&dentry->link_group_list, group->dentry_list);
- return 0;
- }
- group = group->next;
- }
+ /* Single inode--- Add to the list of extra inodes (we can't put
+ * it in the table itself because all the singles have a link
+ * inode ID of 0) */
+ list_add(&dentry->inode_dentry_list, &d_inode->dentry_list);
+ hlist_add_head(&d_inode->hlist, &table->extra_inodes);
+ } else {
+ /* Hard inode that may contain multiple dentries (the code
+ * will work even if the inode actually contains only 1 dentry
+ * though) */
+ struct hlist_node *cur;
- /* Add new hard link group to the table */
+ /* Try adding to existing inode */
+ pos = d_inode->ino % table->capacity;
+ hlist_for_each_entry(inode, cur, &table->array[pos], hlist) {
+ if (inode->ino == d_inode->ino) {
+ list_add(&dentry->inode_dentry_list,
+ &inode->dentry_list);
+ }
+ }
- group = MALLOC(sizeof(struct link_group));
- if (!group)
- return WIMLIB_ERR_NOMEM;
- group->link_group_id = dentry->hard_link;
- group->next = table->array[pos];
- INIT_LIST_HEAD(&dentry->link_group_list);
- group->dentry_list = &dentry->link_group_list;
- table->array[pos] = group;
+ /* Add new inode to the table */
+ list_add(&dentry->inode_dentry_list, &d_inode->dentry_list);
+ hlist_add_head(&d_inode->hlist, &table->array[pos]);
- /* XXX Make the table grow when too many entries have been inserted. */
- table->num_entries++;
+ /* XXX Make the table grow when too many entries have been
+ * inserted. */
+ table->num_entries++;
+ }
return 0;
}
-/* Frees a link group table. */
-void free_link_group_table(struct link_group_table *table)
+/* Frees a inode table. */
+void free_inode_table(struct inode_table *table)
{
- if (!table)
- return;
- if (table->array) {
- for (u64 i = 0; i < table->capacity; i++) {
- struct link_group *group = table->array[i];
- struct link_group *next;
- while (group) {
- next = group->next;
- FREE(group);
- group = next;
- }
- }
+ if (table) {
FREE(table->array);
+ FREE(table);
+ }
+}
+
+static u64
+assign_inos_to_list(struct hlist_head *head, u64 cur_ino)
+{
+ struct inode *inode;
+ struct hlist_node *cur;
+ struct dentry *dentry;
+ hlist_for_each_entry(inode, cur, head, hlist) {
}
- FREE(table);
+ return cur_ino;
}
-/* Assign the link group IDs to dentries in a link group table, and return the
- * next available link group ID. */
-u64 assign_link_groups(struct link_group_table *table)
+/* Assign the inode numbers to dentries in a inode table, and return the
+ * next available inode ID. */
+u64 assign_inode_numbers(struct hlist_head *inode_list)
{
- struct link_group *remaining_groups = NULL;
- u64 id = 1;
- for (u64 i = 0; i < table->capacity; i++) {
- struct link_group *group = table->array[i];
- struct link_group *next_group;
- struct dentry *dentry;
- while (group) {
- next_group = group->next;
- u64 cur_id;
- struct list_head *dentry_list = group->dentry_list;
- if (dentry_list->next == dentry_list) {
- /* Hard link group of size 1. Change the hard
- * link ID to 0 and discard the link_group */
- cur_id = 0;
- FREE(group);
+ struct inode *inode;
+ struct hlist_node *cur;
+ u64 cur_ino = 1;
+ struct dentry *dentry;
+ hlist_for_each_entry(inode, cur, inode_list, hlist) {
+ list_for_each_entry(dentry, &inode->dentry_list, inode_dentry_list)
+ dentry->link_group_id = cur_ino;
+ inode->ino = cur_ino;
+ cur_ino++;
+ }
+ return cur_ino;
+}
+
+
+static void
+print_inode_dentries(const struct inode *inode)
+{
+ struct dentry *dentry;
+ list_for_each_entry(dentry, &inode->dentry_list, inode_dentry_list)
+ printf("`%s'\n", dentry->full_path_utf8);
+}
+
+static void inconsistent_inode(const struct inode *inode)
+{
+ ERROR("An inconsistent hard link group that we cannot correct has been "
+ "detected");
+ ERROR("The dentries are located at the following paths:");
+ print_inode_dentries(inode);
+}
+
+static bool ref_dentries_consistent(const struct dentry * restrict ref_dentry_1,
+ const struct dentry * restrict ref_dentry_2)
+{
+ wimlib_assert(ref_dentry_1 != ref_dentry_2);
+
+ if (ref_dentry_1->inode->num_ads != ref_dentry_2->inode->num_ads)
+ return false;
+ if (ref_dentry_1->inode->security_id != ref_dentry_2->inode->security_id
+ || ref_dentry_1->inode->attributes != ref_dentry_2->inode->attributes)
+ return false;
+ for (unsigned i = 0; i <= ref_dentry_1->inode->num_ads; i++) {
+ const u8 *ref_1_hash, *ref_2_hash;
+ ref_1_hash = inode_stream_hash(ref_dentry_1->inode, i);
+ ref_2_hash = inode_stream_hash(ref_dentry_2->inode, i);
+ if (!hashes_equal(ref_1_hash, ref_2_hash))
+ return false;
+ if (i && !ads_entries_have_same_name(ref_dentry_1->inode->ads_entries[i - 1],
+ ref_dentry_2->inode->ads_entries[i - 1]))
+ return false;
+
+ }
+ return true;
+}
+
+static bool dentries_consistent(const struct dentry * restrict ref_dentry,
+ const struct dentry * restrict dentry)
+{
+ wimlib_assert(ref_dentry != dentry);
+
+ if (ref_dentry->inode->num_ads != dentry->inode->num_ads &&
+ dentry->inode->num_ads != 0)
+ return false;
+ if (ref_dentry->inode->security_id != dentry->inode->security_id
+ || ref_dentry->inode->attributes != dentry->inode->attributes)
+ return false;
+ for (unsigned i = 0; i <= min(ref_dentry->inode->num_ads, dentry->inode->num_ads); i++) {
+ const u8 *ref_hash, *hash;
+ ref_hash = inode_stream_hash(ref_dentry->inode, i);
+ hash = inode_stream_hash(dentry->inode, i);
+ if (!hashes_equal(ref_hash, hash) && !is_zero_hash(hash))
+ return false;
+ if (i && !ads_entries_have_same_name(ref_dentry->inode->ads_entries[i - 1],
+ dentry->inode->ads_entries[i - 1]))
+ return false;
+ }
+ return true;
+}
+
+#ifdef ENABLE_DEBUG
+static void
+print_dentry_list(const struct dentry *first_dentry)
+{
+ const struct dentry *dentry = first_dentry;
+ do {
+ printf("`%s'\n", dentry->full_path_utf8);
+ } while ((dentry = container_of(dentry->inode_dentry_list.next,
+ struct dentry,
+ inode_dentry_list)) != first_dentry);
+}
+
+#endif
+
+static size_t inode_link_count(const struct inode *inode)
+{
+ const struct list_head *cur;
+ size_t size = 0;
+ list_for_each(cur, &inode->dentry_list)
+ size++;
+ return size;
+}
+
+static struct dentry *inode_first_dentry(struct inode *inode)
+{
+ return container_of(inode->dentry_list.next, struct dentry,
+ inode_dentry_list);
+}
+
+/* Fix up a "true" inode and check for inconsistencies */
+static int fix_true_inode(struct inode *inode)
+{
+ struct dentry *dentry;
+ struct dentry *ref_dentry = NULL;
+ u64 last_ctime = 0;
+ u64 last_mtime = 0;
+ u64 last_atime = 0;
+ bool found_short_name = false;
+
+ list_for_each_entry(dentry, &inode->dentry_list, inode_dentry_list) {
+ if (!ref_dentry || ref_dentry->inode->num_ads == 0)
+ ref_dentry = dentry;
+ if (dentry->short_name_len) {
+ if (found_short_name) {
+ ERROR("Multiple short names in hard link "
+ "group!");
+ inconsistent_inode(inode);
+ return WIMLIB_ERR_INVALID_DENTRY;
} else {
- /* Hard link group of size > 1. Assign the
- * dentries in the group the next available hard
- * link IDs and queue the group to be
- * re-inserted into the table. */
- cur_id = id++;
- group->next = remaining_groups;
- remaining_groups = group;
+ found_short_name = true;
}
- struct list_head *cur = dentry_list;
- do {
- dentry = container_of(cur,
- struct dentry,
- link_group_list);
- dentry->hard_link = cur_id;
- cur = cur->next;
- } while (cur != dentry_list);
- group = next_group;
}
+ if (dentry->inode->creation_time > last_ctime)
+ last_ctime = dentry->inode->creation_time;
+ if (dentry->inode->last_write_time > last_mtime)
+ last_mtime = dentry->inode->last_write_time;
+ if (dentry->inode->last_access_time > last_atime)
+ last_atime = dentry->inode->last_access_time;
}
- memset(table->array, 0, table->capacity * sizeof(table->array[0]));
- table->num_entries = 0;
- while (remaining_groups) {
- struct link_group *group = remaining_groups;
- size_t pos = group->link_group_id % table->capacity;
- table->num_entries++;
- group->next = table->array[pos];
- table->array[pos] = group;
- remaining_groups = remaining_groups->next;
+ list_for_each_entry(dentry, &inode->dentry_list, inode_dentry_list) {
+ if (dentry != ref_dentry) {
+ if (!dentries_consistent(ref_dentry, dentry)) {
+ inconsistent_inode(inode);
+ return WIMLIB_ERR_INVALID_DENTRY;
+ }
+ /* Free the unneeded `struct inode'. */
+ free_inode(dentry->inode);
+ dentry->inode = ref_dentry->inode;
+ ref_dentry->inode->link_count++;
+ }
}
- return id;
+ ref_dentry->inode->creation_time = last_ctime;
+ ref_dentry->inode->last_write_time = last_mtime;
+ ref_dentry->inode->last_access_time = last_atime;
+ wimlib_assert(inode_link_count(inode) == inode->link_count);
+ return 0;
}
-static int link_group_free_duplicate_data(struct link_group *group)
+/*
+ * Fixes up a nominal inode.
+ *
+ * By a nominal inode we mean a group of two or more dentries that share
+ * the same hard link group ID.
+ *
+ * If dentries in the inode are found to be inconsistent, we may split the inode
+ * into several "true" inodes. @new_inodes points to a linked list of
+ * these split inodes, and if we create any, they will be added to this list.
+ *
+ * After splitting up each nominal inode into the "true" inodes we
+ * will canonicalize the link group by getting rid of all the superfluous
+ * `struct inodes'. There will be just one `struct inode' for each hard link
+ * group remaining.
+ */
+static int
+fix_nominal_inode(struct inode *inode, struct hlist_head *inode_list)
{
- struct list_head *head;
- struct dentry *master;
-
- head = group->dentry_list;
- master = container_of(head, struct dentry, link_group_list);
- head = head->next;
- master->link_group_master_status = GROUP_MASTER;
- while (head != group->dentry_list) {
- int ret = share_dentry_ads(master,
- container_of(head, struct dentry,
- link_group_list));
+ struct dentry *tmp, *dentry, *ref_dentry;
+ struct hlist_node *cur;
+ int ret;
+ size_t num_true_inodes;
+
+ LIST_HEAD(dentries_with_data_streams);
+ LIST_HEAD(dentries_with_no_data_streams);
+ HLIST_HEAD(true_inodes);
+
+ /* Create a list of dentries in the nominal inode that have at
+ * least one data stream with a non-zero hash, and another list that
+ * contains the dentries that have a zero hash for all data streams. */
+ list_for_each_entry(dentry, &inode->dentry_list, inode_dentry_list) {
+ for (unsigned i = 0; i <= dentry->inode->num_ads; i++) {
+ const u8 *hash;
+ hash = inode_stream_hash(dentry->inode, i);
+ if (!is_zero_hash(hash)) {
+ list_add(&dentry->tmp_list,
+ &dentries_with_data_streams);
+ goto next_dentry;
+ }
+ }
+ list_add(&dentry->tmp_list,
+ &dentries_with_no_data_streams);
+ next_dentry:
+ ;
+ }
+
+ /* If there are no dentries with data streams, we require the nominal
+ * inode to be a true inode */
+ if (list_empty(&dentries_with_data_streams)) {
+ #ifdef ENABLE_DEBUG
+ {
+ if (inode->link_count > 1) {
+ DEBUG("Found link group of size %zu without "
+ "any data streams:", inode->link_count);
+ print_inode_dentries(inode);
+ DEBUG("We are going to interpret it as true "
+ "link group, provided that the dentries "
+ "are consistent.");
+ }
+ }
+ #endif
+ hlist_add_head(&inode->hlist, inode_list);
+ return fix_true_inode(inode);
+ }
+
+ /* One or more dentries had data streams specified. We check each of
+ * these dentries for consistency with the others to form a set of true
+ * inodes. */
+ num_true_inodes = 0;
+ list_for_each_entry(dentry, &dentries_with_data_streams, tmp_list)
+ {
+ /* Look for a true inode that is consistent with
+ * this dentry and add this dentry to it. Or, if none
+ * of the true inodes are consistent with this
+ * dentry, make a new one. */
+ hlist_for_each_entry(inode, cur, &true_inodes, hlist) {
+ if (ref_dentries_consistent(inode_first_dentry(inode), dentry)) {
+ list_add(&dentry->inode_dentry_list,
+ &inode->dentry_list);
+ goto next_dentry_2;
+ }
+ }
+ num_true_inodes++;
+ hlist_add_head(&dentry->inode->hlist, &true_inodes);
+ INIT_LIST_HEAD(&dentry->inode->dentry_list);
+ list_add(&dentry->inode_dentry_list, &dentry->inode->dentry_list);
+next_dentry_2:
+ ;
+ }
+
+ wimlib_assert(num_true_inodes != 0);
+
+ /* If there were dentries with no data streams, we require there to only
+ * be one true inode so that we know which inode to assign the
+ * streamless dentries to. */
+ if (!list_empty(&dentries_with_no_data_streams)) {
+ if (num_true_inodes != 1) {
+ ERROR("Hard inode ambiguity detected!");
+ ERROR("We split up inode 0x%"PRIx64" due to "
+ "inconsistencies,", inode->ino);
+ ERROR("but dentries with no stream information remained. "
+ "We don't know which true hard link");
+ ERROR("inode to assign them to.");
+ return WIMLIB_ERR_INVALID_DENTRY;
+ }
+ /* Assign the streamless dentries to the one and only true link
+ * inode. */
+ ref_dentry = inode_first_dentry(inode);
+ list_for_each_entry(dentry, &dentries_with_no_data_streams, tmp_list)
+ list_add(&dentry->inode_dentry_list, &inode->dentry_list);
+ }
+ if (num_true_inodes != 1) {
+ #ifdef ENABLE_DEBUG
+ {
+ printf("Split nominal inode 0x%"PRIx64" into %zu "
+ "inodes:\n",
+ inode->ino, num_true_inodes);
+ puts("------------------------------------------------------------------------------");
+ size_t i = 1;
+ hlist_for_each_entry(inode, cur, &true_inodes, hlist) {
+ printf("[Split inode %zu]\n", i++);
+ print_inode_dentries(inode);
+ putchar('\n');
+ }
+ puts("------------------------------------------------------------------------------");
+ }
+ #endif
+ }
+
+ hlist_for_each_entry(inode, cur, &true_inodes, hlist) {
+ hlist_add_head(&inode->hlist, inode_list);
+ ret = fix_true_inode(inode);
if (ret != 0)
return ret;
}
return 0;
}
-int link_groups_free_duplicate_data(struct link_group_table *table)
+/*
+ * Goes through each inode and shares the inodes among members of a hard
+ * inode.
+ *
+ * In the process, the dentries in each inode are checked for consistency.
+ * If they contain data features that indicate they cannot really be in the same
+ * inode, this should be an error, but in reality this case needs to
+ * be handled, so we split the dentries into different inodes.
+ */
+int fix_inodes(struct inode_table *table, struct hlist_head *inode_list)
{
+ struct inode *inode;
+ struct hlist_node *cur, *tmp;
+ int ret = 0;
+ INIT_HLIST_HEAD(inode_list);
for (u64 i = 0; i < table->capacity; i++) {
- struct link_group *group = table->array[i];
- while (group) {
- int ret = link_group_free_duplicate_data(group);
+ hlist_for_each_entry_safe(inode, cur, tmp, &table->array[i], hlist) {
+ ret = fix_nominal_inode(inode, inode_list);
if (ret != 0)
- return ret;
- group = group->next;
+ break;
}
}
- return 0;
+ return ret;
}
git://wimlib.net / wimlib / blobdiff