X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fhardlink.c;h=5a0b62058eab337b8cd892efc333d97bfd707730;hp=9a128d4619ed4e3d1d1aab5375513c4069ed022a;hb=c7af42d3d894338bbd1cb7f4b77948f746485482;hpb=004c7fd634328ab9b3c4b479097a10ca12ae38d7 diff --git a/src/hardlink.c b/src/hardlink.c index 9a128d46..5a0b6205 100644 --- a/src/hardlink.c +++ b/src/hardlink.c @@ -1,175 +1,474 @@ +/* + * hardlink.c + * + * Code to deal with hard links in WIMs. + */ + +/* + * 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 + * \ / | wim_inode| | wim_inode| + * dentry ------------ ------------ + * ^ ^ + * | | + * | | dentry + * ----------- ----------- / \ + * dentry<---| struct | | struct |---> dentry dentry + * / | wim_inode| | wim_inode| \ / + * dentry ------------ ------------ dentry + * ^ ^ + * | | + * ----------------- + * wim_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 wim_inode_table { + /* Fields for the hash table */ + struct hlist_head *array; u64 num_entries; u64 capacity; + + /* + * 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 + * number with some other inode until assign_inode_numbers() is + * called. + */ + struct hlist_head extra_inodes; }; -#include +static inline void destroy_inode_table(struct wim_inode_table *table) +{ + FREE(table->array); +} -struct link_group_table *new_link_group_table(u64 capacity) +static int init_inode_table(struct wim_inode_table *table, size_t capacity) { - return (struct link_group_table*)new_lookup_table(capacity); + table->array = CALLOC(capacity, sizeof(table->array[0])); + if (!table->array) { + ERROR("Cannot initalize inode table: out of memory"); + return WIMLIB_ERR_NOMEM; + } + table->num_entries = 0; + table->capacity = capacity; + INIT_HLIST_HEAD(&table->extra_inodes); + return 0; } -/* 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. - */ -int link_group_table_insert(struct dentry *dentry, struct link_group_table *table) +static inline size_t inode_link_count(const struct wim_inode *inode) { - size_t pos; - struct link_group *group; + const struct list_head *cur; + size_t size = 0; + list_for_each(cur, &inode->i_dentry) + size++; + return size; +} - if (dentry->hard_link == 0) { - INIT_LIST_HEAD(&dentry->link_group_list); - return 0; - } +/* Insert a dentry into the inode table based on the inode number of the + * attached inode (which came from the hard link group ID field of the on-disk + * WIM dentry) */ +static int inode_table_insert(struct wim_dentry *dentry, void *__table) +{ + struct wim_inode_table *table = __table; + struct wim_inode *d_inode = dentry->d_inode; - /* 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; + if (d_inode->i_ino == 0) { + /* A dentry with a hard link group ID of 0 indicates that it's + * in a hard link group by itself. Add it to the list of extra + * inodes rather than inserting it into the hash lists. */ + hlist_add_head(&d_inode->i_hlist, &table->extra_inodes); + + wimlib_assert(d_inode->i_dentry.next == &dentry->d_alias); + wimlib_assert(d_inode->i_dentry.prev == &dentry->d_alias); + wimlib_assert(d_inode->i_nlink == 1); + } else { + size_t pos; + struct wim_inode *inode; + struct hlist_node *cur; + + /* Try adding this dentry to an existing inode */ + pos = d_inode->i_ino % table->capacity; + hlist_for_each_entry(inode, cur, &table->array[pos], i_hlist) { + if (inode->i_ino == d_inode->i_ino) { + inode_add_dentry(dentry, inode); + inode->i_nlink++; + return 0; + } } - group = group->next; - } - /* Add new hard link group to the table */ + /* No inode in the table has the same number as this one, so add + * it to the table. */ + hlist_add_head(&d_inode->i_hlist, &table->array[pos]); - 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++; + wimlib_assert(d_inode->i_dentry.next == &dentry->d_alias); + wimlib_assert(d_inode->i_dentry.prev == &dentry->d_alias); + wimlib_assert(d_inode->i_nlink == 1); + + /* 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) +static void print_inode_dentries(const struct wim_inode *inode) +{ + struct wim_dentry *dentry; + inode_for_each_dentry(dentry, inode) + printf("`%s'\n", dentry->full_path_utf8); +} + +static void inconsistent_inode(const struct wim_inode *inode) { - 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; + ERROR("An inconsistent hard link group that cannot be corrected has " + "been detected"); + ERROR("The dentries are located at the following paths:"); +#ifdef ENABLE_ERROR_MESSAGES + print_inode_dentries(inode); +#endif +} + +static bool ref_inodes_consistent(const struct wim_inode * restrict ref_inode_1, + const struct wim_inode * restrict ref_inode_2) +{ + wimlib_assert(ref_inode_1 != ref_inode_2); + + if (ref_inode_1->i_num_ads != ref_inode_2->i_num_ads) + return false; + if (ref_inode_1->i_security_id != ref_inode_2->i_security_id + || ref_inode_1->i_attributes != ref_inode_2->i_attributes) + return false; + for (unsigned i = 0; i <= ref_inode_1->i_num_ads; i++) { + const u8 *ref_1_hash, *ref_2_hash; + ref_1_hash = inode_stream_hash(ref_inode_1, i); + ref_2_hash = inode_stream_hash(ref_inode_2, i); + if (!hashes_equal(ref_1_hash, ref_2_hash)) + return false; + if (i && !ads_entries_have_same_name(&ref_inode_1->i_ads_entries[i - 1], + &ref_inode_2->i_ads_entries[i - 1])) + return false; + + } + return true; +} + +static bool inodes_consistent(const struct wim_inode * restrict ref_inode, + const struct wim_inode * restrict inode) +{ + wimlib_assert(ref_inode != inode); + + if (ref_inode->i_num_ads != inode->i_num_ads && + inode->i_num_ads != 0) + return false; + if (ref_inode->i_security_id != inode->i_security_id + || ref_inode->i_attributes != inode->i_attributes) + return false; + for (unsigned i = 0; i <= min(ref_inode->i_num_ads, inode->i_num_ads); i++) { + const u8 *ref_hash, *hash; + ref_hash = inode_stream_hash(ref_inode, i); + hash = inode_stream_hash(inode, i); + if (!hashes_equal(ref_hash, hash) && !is_zero_hash(hash)) + return false; + if (i && !ads_entries_have_same_name(&ref_inode->i_ads_entries[i - 1], + &inode->i_ads_entries[i - 1])) + return false; + } + return true; +} + +/* Fix up a "true" inode and check for inconsistencies */ +static int fix_true_inode(struct wim_inode *inode, struct hlist_head *inode_list) +{ + struct wim_dentry *dentry; + struct wim_dentry *ref_dentry = NULL; + struct wim_inode *ref_inode; + u64 last_ctime = 0; + u64 last_mtime = 0; + u64 last_atime = 0; + + inode_for_each_dentry(dentry, inode) { + if (!ref_dentry || dentry->d_inode->i_num_ads > ref_dentry->d_inode->i_num_ads) + ref_dentry = dentry; + if (dentry->d_inode->i_creation_time > last_ctime) + last_ctime = dentry->d_inode->i_creation_time; + if (dentry->d_inode->i_last_write_time > last_mtime) + last_mtime = dentry->d_inode->i_last_write_time; + if (dentry->d_inode->i_last_access_time > last_atime) + last_atime = dentry->d_inode->i_last_access_time; + } + + ref_inode = ref_dentry->d_inode; + ref_inode->i_nlink = 1; + hlist_add_head(&ref_inode->i_hlist, inode_list); + + list_del(&inode->i_dentry); + list_add(&ref_inode->i_dentry, &ref_dentry->d_alias); + + inode_for_each_dentry(dentry, ref_inode) { + if (dentry != ref_dentry) { + if (!inodes_consistent(ref_inode, dentry->d_inode)) { + inconsistent_inode(ref_inode); + return WIMLIB_ERR_INVALID_DENTRY; } + /* Free the unneeded `struct wim_inode'. */ + dentry->d_inode->i_hlist.next = NULL; + dentry->d_inode->i_hlist.pprev = NULL; + free_inode(dentry->d_inode); + dentry->d_inode = ref_inode; + ref_inode->i_nlink++; } - FREE(table->array); } - FREE(table); + ref_inode->i_creation_time = last_ctime; + ref_inode->i_last_write_time = last_mtime; + ref_inode->i_last_access_time = last_atime; + wimlib_assert(inode_link_count(ref_inode) == ref_inode->i_nlink); + return 0; } -/* 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) +/* + * 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. + * + * After splitting up each nominal inode into the "true" inodes we will + * canonicalize the link group by getting rid of all the unnecessary `struct + * wim_inode's. There will be just one `struct wim_inode' for each hard link + * group remaining. + */ +static int fix_nominal_inode(struct wim_inode *inode, + 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); - } 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; + struct wim_dentry *dentry; + struct hlist_node *cur, *tmp; + int ret; + size_t num_true_inodes; + + wimlib_assert(inode->i_nlink == inode_link_count(inode)); + + 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. */ + inode_for_each_dentry(dentry, inode) { + for (unsigned i = 0; i <= dentry->d_inode->i_num_ads; i++) { + const u8 *hash; + hash = inode_stream_hash(dentry->d_inode, i); + if (!is_zero_hash(hash)) { + list_add(&dentry->tmp_list, + &dentries_with_data_streams); + goto next_dentry; } - 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; } + list_add(&dentry->tmp_list, + &dentries_with_no_data_streams); + next_dentry: + ; } - 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; + /* 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->i_nlink > 1) { + DEBUG("Found link group of size %u without " + "any data streams:", inode->i_nlink); + print_inode_dentries(inode); + DEBUG("We are going to interpret it as true " + "link group, provided that the dentries " + "are consistent."); + } + #endif + return fix_true_inode(inode, inode_list); } - return id; -} -static int link_group_free_duplicate_data(struct link_group *group) -{ - 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)); + /* 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, add a new one (if that happens, + * we have split the hard link group). */ + hlist_for_each_entry(inode, cur, &true_inodes, i_hlist) { + if (ref_inodes_consistent(inode, dentry->d_inode)) { + inode_add_dentry(dentry, inode); + goto next_dentry_2; + } + } + num_true_inodes++; + INIT_LIST_HEAD(&dentry->d_inode->i_dentry); + inode_add_dentry(dentry, dentry->d_inode); + hlist_add_head(&dentry->d_inode->i_hlist, &true_inodes); +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->i_ino); + ERROR("but dentries with no stream information remained. " + "We don't know which inode"); + ERROR("to assign them to."); + return WIMLIB_ERR_INVALID_DENTRY; + } + inode = container_of(true_inodes.first, struct wim_inode, i_hlist); + /* Assign the streamless dentries to the one and only true + * inode. */ + list_for_each_entry(dentry, &dentries_with_no_data_streams, tmp_list) + inode_add_dentry(dentry, inode); + } + #ifdef ENABLE_DEBUG + if (num_true_inodes != 1) { + inode = container_of(true_inodes.first, struct wim_inode, i_hlist); + + printf("Split nominal inode 0x%"PRIx64" into %zu " + "inodes:\n", + inode->i_ino, num_true_inodes); + puts("------------------------------------------------------------------------------"); + size_t i = 1; + hlist_for_each_entry(inode, cur, &true_inodes, i_hlist) { + printf("[Split inode %zu]\n", i++); + print_inode_dentries(inode); + putchar('\n'); + } + puts("------------------------------------------------------------------------------"); + } + #endif + + hlist_for_each_entry_safe(inode, cur, tmp, &true_inodes, i_hlist) { + ret = fix_true_inode(inode, inode_list); if (ret != 0) return ret; } return 0; } -int link_groups_free_duplicate_data(struct link_group_table *table) +static int fix_inodes(struct wim_inode_table *table, + struct hlist_head *inode_list) { + struct wim_inode *inode; + struct hlist_node *cur, *tmp; + int ret; + 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], i_hlist) { + ret = fix_nominal_inode(inode, inode_list); if (ret != 0) return ret; - group = group->next; } } + hlist_for_each_safe(cur, tmp, &table->extra_inodes) + hlist_add_head(cur, inode_list); return 0; } + +/* + * dentry_tree_fix_inodes(): + * + * This function takes as input a tree of WIM dentries that initially has a + * different inode associated with each dentry. Sets of dentries that should + * share the same inode (a.k.a. hard link groups) are built using the i_ino + * field of each inode, then the link count and alias list for one inode in each + * set is set correctly and the unnecessary struct wim_inode's freed. The + * effect is to correctly associate exactly one struct wim_inode with each + * original inode, regardless of how many dentries are aliases for that inode. + * + * The special inode number of 0 indicates that the dentry is in a hard link + * group by itself, and therefore has a 'struct wim_inode' with i_nlink=1 to + * itself. + * + * This function also checks the dentries in each hard link group for + * consistency. In some WIMs, such as install.wim for some versions of Windows + * 7, dentries can share the same hard link group ID but not actually be hard + * linked to each other (based on conflicting information, such as file + * contents). This should be an error, but this case needs be handled. So, + * each "nominal" inode (the inode based on the inode numbers provided in the + * WIM) is examined for consistency and may be split into multiple "true" inodes + * that are maximally sized consistent sets of dentries. + * + * Return 0 on success; WIMLIB_ERR_NOMEM or WIMLIB_ERR_INVALID_DENTRY on + * failure. On success, the list of "true" inodes, linked by the i_hlist field, + * is returned in the hlist @inode_list. + */ +int dentry_tree_fix_inodes(struct wim_dentry *root, struct hlist_head *inode_list) +{ + struct wim_inode_table inode_tab; + int ret; + + DEBUG("Inserting dentries into inode table"); + ret = init_inode_table(&inode_tab, 9001); + if (ret != 0) + return ret; + + for_dentry_in_tree(root, inode_table_insert, &inode_tab); + + DEBUG("Cleaning up the hard link groups"); + ret = fix_inodes(&inode_tab, inode_list); + destroy_inode_table(&inode_tab); + return ret; +} + +/* Assign inode numbers to a list of inodes and return the next available + * number. */ +u64 assign_inode_numbers(struct hlist_head *inode_list) +{ + DEBUG("Assigning inode numbers"); + struct wim_inode *inode; + struct hlist_node *cur; + u64 cur_ino = 1; + hlist_for_each_entry(inode, cur, inode_list, i_hlist) { + inode->i_ino = cur_ino; + cur_ino++; + } + return cur_ino; +}