|
|
/*
* 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 */
|
