FreeBSD/Linux Kernel Cross Reference
sys/fs/ntfs/index.h

     /*
      * 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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