#include "list.h"
#include "lookup_table.h"
+/* Hard link group; it's identified by its hard link group ID and consists of a
+ * circularly linked list of dentries. */
struct link_group {
u64 link_group_id;
struct link_group *next;
struct list_head *dentry_list;
};
+/* Hash table to find hard link groups, identified by their hard link group ID.
+ * */
struct link_group_table {
struct link_group **array;
u64 num_entries;
struct link_group *singles;
};
-#include <sys/mman.h>
-
+/* Returns pointer to a new link group table having the specified capacity */
struct link_group_table *new_link_group_table(u64 capacity)
{
struct link_group_table *table;
return NULL;
}
-/* Insert a dentry into the hard link group table based on its hard link group
+/*
+ * Insert a dentry into the hard link group table based on its hard link group
* 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 the hard link group ID is 0, this is a no-op and the dentry is not
- * inserted.
+ * If the hard link group ID is 0, this indicates a dentry that's in a hard link
+ * group by itself (has a link count of 1). We can't insert it into the hash
+ * table itself because we don't know what hard link group IDs 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 hard link group
+ * IDs later.
*/
int link_group_table_insert(struct dentry *dentry, struct link_group_table *table)
{
table->singles = group;
INIT_LIST_HEAD(&dentry->link_group_list);
group->dentry_list = &dentry->link_group_list;
- return 0;
- }
+ } else {
+ /* Hard link group that may should multiple dentries (the code
+ * will work even if the group actually contains only 1 dentry
+ * though) */
- /* 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;
+ /* 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;
}
- group = group->next;
- }
- /* Add new hard link group to the table */
+ /* Add new hard link group to the table */
- 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;
+ 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;
- /* 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)
{
+ struct link_group *single, *next;
+
if (!table)
return;
if (table->array) {
}
FREE(table->array);
}
+ single = table->singles;
+ while (single) {
+ next = single->next;
+ FREE(single);
+ single = next;
+ }
+
FREE(table);
}
u64 assign_link_groups(struct link_group_table *table)
{
DEBUG("Assigning link groups");
+
+ /* Assign consecutive link group IDs to each link group in the hash
+ * table */
u64 id = 1;
for (u64 i = 0; i < table->capacity; i++) {
struct link_group *group = table->array[i];
group = group->next;
}
}
- /* Singles */
+ /* Assign link group IDs to the link groups that previously had link
+ * group IDs of 0, and insert them into the hash table */
struct link_group *single = table->singles;
while (single) {
struct dentry *dentry;
return id;
}
+static bool dentries_have_same_ads(const struct dentry *d1,
+ const struct dentry *d2)
+{
+ /* Verify stream names and hashes are the same */
+ for (u16 i = 0; i < d1->num_ads; i++) {
+ if (strcmp(d1->ads_entries[i].stream_name_utf8,
+ d2->ads_entries[i].stream_name_utf8) != 0)
+ return false;
+ if (memcmp(d1->ads_entries[i].hash,
+ d2->ads_entries[i].hash,
+ WIM_HASH_SIZE) != 0)
+ return false;
+ }
+ return true;
+}
+
+/* Share the alternate stream entries between hard-linked dentries. */
+static int share_dentry_ads(struct dentry *owner, struct dentry *user)
+{
+ const char *mismatch_type;
+ wimlib_assert(owner->num_ads == 0 ||
+ owner->ads_entries != user->ads_entries);
+ if (owner->attributes != user->attributes) {
+ mismatch_type = "attributes";
+ goto mismatch;
+ }
+ if (owner->attributes & FILE_ATTRIBUTE_DIRECTORY) {
+ WARNING("`%s' is hard-linked to `%s', which is a directory ",
+ user->full_path_utf8, owner->full_path_utf8);
+ return WIMLIB_ERR_INVALID_DENTRY;
+ }
+ if (owner->security_id != user->security_id) {
+ mismatch_type = "security ID";
+ goto mismatch;
+ }
+ if (memcmp(owner->hash, user->hash, WIM_HASH_SIZE) != 0) {
+ mismatch_type = "main file resource";
+ goto mismatch;
+ }
+ if (!dentries_have_same_ads(owner, user)) {
+ mismatch_type = "Alternate Stream Entries";
+ goto mismatch;
+ }
+ dentry_free_ads_entries(user);
+ user->ads_entries = owner->ads_entries;
+ user->ads_entries_status = ADS_ENTRIES_USER;
+ return 0;
+mismatch:
+ WARNING("Dentries `%s' and `%s' in the same hard-link group but "
+ "do not share the same %s",
+ owner->full_path_utf8, user->full_path_utf8,
+ mismatch_type);
+ return WIMLIB_ERR_INVALID_DENTRY;
+}
+
static int link_group_free_duplicate_data(struct link_group *group,
struct link_group **bad_links)
{
- struct dentry *master, *slave, *tmp;
+ struct dentry *owner, *user, *tmp;
- master = container_of(group->dentry_list, struct dentry,
+ owner = container_of(group->dentry_list, struct dentry,
link_group_list);
- master->link_group_master_status = GROUP_MASTER;
+ owner->ads_entries_status = ADS_ENTRIES_OWNER;
- list_for_each_entry_safe(slave, tmp, group->dentry_list,
+ list_for_each_entry_safe(user, tmp, group->dentry_list,
link_group_list)
{
- /* I would it to be an error if two dentries are the same hard
- * link group but have irreconcilable differences such as
- * different file permissions, but unfortunately some of M$'s
+ /* I would like it to be an error if two dentries are in the
+ * same hard link group but have irreconcilable differences such
+ * as different file permissions, but unfortunately some of M$'s
* WIMs contain many instances of this error. This problem is
* worked around here by splitting each offending dentry off
* into its own hard link group. */
- if (share_dentry_ads(master, slave) != 0) {
+ if (share_dentry_ads(owner, user) != 0) {
struct link_group *single;
single = MALLOC(sizeof(struct link_group));
if (!single)
return WIMLIB_ERR_NOMEM;
- list_del(&slave->link_group_list);
- INIT_LIST_HEAD(&slave->link_group_list);
+ list_del(&user->link_group_list);
+ INIT_LIST_HEAD(&user->link_group_list);
single->link_group_id = 0;
single->next = *bad_links;
- single->dentry_list = &slave->link_group_list;
+ single->dentry_list = &user->link_group_list;
*bad_links = single;
- slave->link_group_master_status = GROUP_INDEPENDENT;
+ user->ads_entries_status = ADS_ENTRIES_OWNER;
}
}
return 0;
}
+/*
+ * Goes through each link group and shares the ads_entries (Alternate Data
+ * Stream entries) field of each dentry between members of a hard link group.
+ *
+ * In the process, the dentries in each link group are checked for consistency.
+ * If they contain data features that indicate they cannot really be in the same
+ * hard link group, this should be an error, but in reality this case needs to
+ * be handled, so we split the dentries into different hard link groups.
+ *
+ * One of the dentries in the group is arbitrarily assigned the role of "owner"
+ * (ADS_ENTRIES_OWNER), while the others are "users" (ADS_ENTRIES_USER).
+ */
int link_groups_free_duplicate_data(struct link_group_table *table)
{
for (u64 i = 0; i < table->capacity; i++) {
git://wimlib.net / wimlib / blobdiff