--- /dev/null
+/*
+ * index.h - Defines for NTFS kernel index handling. Part of the Linux-NTFS
+ * project.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ *
+ * This program/include file 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program/include file 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 this program (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _LINUX_NTFS_INDEX_H
+#define _LINUX_NTFS_INDEX_H
+
+#include <linux/fs.h>
+
+#include "types.h"
+#include "layout.h"
+#include "inode.h"
+#include "attrib.h"
+#include "mft.h"
+#include "aops.h"
+
+/**
+ * @idx_ni: index inode containing the @entry described by this context
+ * @entry: index entry (points into @ir or @ia)
+ * @data: index entry data (points into @entry)
+ * @data_len: length in bytes of @data
+ * @is_in_root: 'true' if @entry is in @ir and 'false' if it is in @ia
+ * @ir: index root if @is_in_root and NULL otherwise
+ * @actx: attribute search context if @is_in_root and NULL otherwise
+ * @base_ni: base inode if @is_in_root and NULL otherwise
+ * @ia: index block if @is_in_root is 'false' and NULL otherwise
+ * @page: page if @is_in_root is 'false' and NULL otherwise
+ *
+ * @idx_ni is the index inode this context belongs to.
+ *
+ * @entry is the index entry described by this context. @data and @data_len
+ * are the index entry data and its length in bytes, respectively. @data
+ * simply points into @entry. This is probably what the user is interested in.
+ *
+ * If @is_in_root is 'true', @entry is in the index root attribute @ir described
+ * by the attribute search context @actx and the base inode @base_ni. @ia and
+ * @page are NULL in this case.
+ *
+ * If @is_in_root is 'false', @entry is in the index allocation attribute and @ia
+ * and @page point to the index allocation block and the mapped, locked page it
+ * is in, respectively. @ir, @actx and @base_ni are NULL in this case.
+ *
+ * To obtain a context call ntfs_index_ctx_get().
+ *
+ * We use this context to allow ntfs_index_lookup() to return the found index
+ * @entry and its @data without having to allocate a buffer and copy the @entry
+ * and/or its @data into it.
+ *
+ * When finished with the @entry and its @data, call ntfs_index_ctx_put() to
+ * free the context and other associated resources.
+ *
+ * If the index entry was modified, call flush_dcache_index_entry_page()
+ * immediately after the modification and either ntfs_index_entry_mark_dirty()
+ * or ntfs_index_entry_write() before the call to ntfs_index_ctx_put() to
+ * ensure that the changes are written to disk.
+ */
+typedef struct {
+ ntfs_inode *idx_ni;
+ INDEX_ENTRY *entry;
+ void *data;
+ u16 data_len;
+ bool is_in_root;
+ INDEX_ROOT *ir;
+ ntfs_attr_search_ctx *actx;
+ ntfs_inode *base_ni;
+ INDEX_ALLOCATION *ia;
+ struct page *page;
+} ntfs_index_context;
+
+extern ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni);
+extern void ntfs_index_ctx_put(ntfs_index_context *ictx);
+
+extern int ntfs_index_lookup(const void *key, const int key_len,
+ ntfs_index_context *ictx);
+
+#ifdef NTFS_RW
+
+/**
+ * ntfs_index_entry_flush_dcache_page - flush_dcache_page() for index entries
+ * @ictx: ntfs index context describing the index entry
+ *
+ * Call flush_dcache_page() for the page in which an index entry resides.
+ *
+ * This must be called every time an index entry is modified, just after the
+ * modification.
+ *
+ * If the index entry is in the index root attribute, simply flush the page
+ * containing the mft record containing the index root attribute.
+ *
+ * If the index entry is in an index block belonging to the index allocation
+ * attribute, simply flush the page cache page containing the index block.
+ */
+static inline void ntfs_index_entry_flush_dcache_page(ntfs_index_context *ictx)
+{
+ if (ictx->is_in_root)
+ flush_dcache_mft_record_page(ictx->actx->ntfs_ino);
+ else
+ flush_dcache_page(ictx->page);
+}
+
+/**
+ * ntfs_index_entry_mark_dirty - mark an index entry dirty
+ * @ictx: ntfs index context describing the index entry
+ *
+ * Mark the index entry described by the index entry context @ictx dirty.
+ *
+ * If the index entry is in the index root attribute, simply mark the mft
+ * record containing the index root attribute dirty. This ensures the mft
+ * record, and hence the index root attribute, will be written out to disk
+ * later.
+ *
+ * If the index entry is in an index block belonging to the index allocation
+ * attribute, mark the buffers belonging to the index record as well as the
+ * page cache page the index block is in dirty. This automatically marks the
+ * VFS inode of the ntfs index inode to which the index entry belongs dirty,
+ * too (I_DIRTY_PAGES) and this in turn ensures the page buffers, and hence the
+ * dirty index block, will be written out to disk later.
+ */
+static inline void ntfs_index_entry_mark_dirty(ntfs_index_context *ictx)
+{
+ if (ictx->is_in_root)
+ mark_mft_record_dirty(ictx->actx->ntfs_ino);
+ else
+ mark_ntfs_record_dirty(ictx->page,
+ (u8*)ictx->ia - (u8*)page_address(ictx->page));
+}
+
+#endif /* NTFS_RW */
+
+#endif /* _LINUX_NTFS_INDEX_H */
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