Save memory by using a singly-linked list for extraction aliases

[wimlib] / include / wimlib / dentry.h

diff --git a/include/wimlib/dentry.h b/include/wimlib/dentry.h
index 241dc56d58c47493b059cc1926b936c21ffabe78..c6d1f12d28df0c373c80e61f40330d861204c5ea 100644 (file)
--- a/include/wimlib/dentry.h
+++ b/include/wimlib/dentry.h
@@ -21,28 +21,18 @@ struct blob_table;
  * tree for each image in the WIM.
  *
  * Note that this is a directory entry and not an inode.  Since NTFS allows hard
- * links, it's possible for an NTFS inode to correspond to multiple WIM dentries.
- * The hard link group ID field of the on-disk WIM dentry tells us the number of
- * the NTFS inode that the dentry corresponds to (and this gets placed in
- * d_inode->i_ino).
+ * links, it's possible for an NTFS inode to correspond to multiple WIM
+ * dentries.  The hard link group ID field of the on-disk WIM dentry tells us
+ * the number of the NTFS inode that the dentry corresponds to (and this gets
+ * placed in d_inode->i_ino).
  *
  * Unfortunately, WIM files do not have an analogue to an inode; instead certain
- * information, such as file attributes, the security descriptor, and file
- * streams is replicated in each hard-linked dentry, even though this
- * information really is associated with an inode.  In-memory, we fix up this
- * flaw by allocating a `struct wim_inode' for each dentry that contains some of
- * this duplicated information, then combining the inodes for each hard link
- * group together.
- *
- * Confusingly, it's possible for stream information to be missing from a dentry
- * in a hard link set, in which case the stream information needs to be gotten
- * from one of the other dentries in the hard link set.  In addition, it is
- * possible for dentries to have inconsistent security IDs, file attributes, or
- * file streams when they share the same hard link ID (don't even ask.  I hope
- * that Microsoft may have fixed this problem, since I've only noticed it in the
- * 'install.wim' for Windows 7).  For those dentries, we have to use the
- * conflicting fields to split up the hard link groups.  (See
- * dentry_tree_fix_inodes() in inode_fixup.c.)
+ * information, such as file attributes, the security descriptor, and streams is
+ * replicated in each hard-linked dentry, even though this information really is
+ * associated with an inode.  In-memory, we fix up this flaw by allocating a
+ * `struct wim_inode' for each dentry that contains some of this duplicated
+ * information, then combining the inodes for each hard link group together.
+ * (See dentry_tree_fix_inodes().)
  */
 struct wim_dentry {
        /* Pointer to the inode for this dentry.  This will contain some
@@ -67,7 +57,7 @@ struct wim_dentry {
 
        /* Linked list node that places this dentry in the list of aliases for
         * its inode (d_inode) */
-       struct list_head d_alias;
+       struct hlist_node d_alias;
 
        /* Pointer to the UTF-16LE short filename (malloc()ed buffer), or NULL
         * if this dentry has no short name.  */
@@ -126,18 +116,12 @@ struct wim_dentry {
         * extracted as part of the current extraction operation.  */
        struct list_head d_extraction_list_node;
 
-       /* (Extraction only) Linked list node that connects all dentries being
-        * extracted as aliases of the same inode as part of the current
-        * extraction operation.  */
-       struct list_head d_extraction_alias_node;
+       /* (Extraction only) Pointer to the next alias for this dentry's inode
+        * that needs to be extracted as part of the current extraction
+        * operation, or NULL if this is the last alias.  */
+       struct wim_dentry *d_next_extraction_alias;
 };
 
-static inline bool
-dentry_is_first_in_inode(const struct wim_dentry *dentry)
-{
-       return inode_first_dentry(dentry->d_inode) == dentry;
-}
-
 static inline bool
 will_extract_dentry(const struct wim_dentry *dentry)
 {
@@ -231,13 +215,12 @@ extern tchar *
 dentry_full_path(struct wim_dentry *dentry);
 
 extern int
-new_dentry(const tchar *name, struct wim_dentry **dentry_ret);
-
-extern int
-new_dentry_with_inode(const tchar *name, struct wim_dentry **dentry_ret);
+new_dentry_with_new_inode(const tchar *name, bool set_timestamps,
+                         struct wim_dentry **dentry_ret);
 
 extern int
-new_dentry_with_timeless_inode(const tchar *name, struct wim_dentry **dentry_ret);
+new_dentry_with_existing_inode(const tchar *name, struct wim_inode *inode,
+                              struct wim_dentry **dentry_ret);
 
 extern void
 dentry_tree_clear_inode_visited(struct wim_dentry *root);