linux-imx

/*

 * index.c - NTFS kernel index handling.  Part of the Linux-NTFS project.

 *

 * Copyright (c) 2004-2005 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

 */

​

#include <linux/slab.h>

​

#include "aops.h"

#include "collate.h"

#include "debug.h"

#include "index.h"

#include "ntfs.h"

​

/**

 * ntfs_index_ctx_get - allocate and initialize a new index context

 * @idx_ni: ntfs index inode with which to initialize the context

 *

 * Allocate a new index context, initialize it with @idx_ni and return it.

 * Return NULL if allocation failed.

 *

 * Locking:  Caller must hold i_mutex on the index inode.

 */

ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni)

{

    ntfs_index_context *ictx;

​

    ictx = kmem_cache_alloc(ntfs_index_ctx_cache, GFP_NOFS);

    if (ictx)

        *ictx = (ntfs_index_context){ .idx_ni = idx_ni };

    return ictx;

}

​

/**

 * ntfs_index_ctx_put - release an index context

 * @ictx:   index context to free

 *

 * Release the index context @ictx, releasing all associated resources.

 *

 * Locking:  Caller must hold i_mutex on the index inode.

 */

void ntfs_index_ctx_put(ntfs_index_context *ictx)

{

    if (ictx->entry) {

        if (ictx->is_in_root) {

            if (ictx->actx)

                ntfs_attr_put_search_ctx(ictx->actx);

            if (ictx->base_ni)

                unmap_mft_record(ictx->base_ni);

        } else {

            struct page *page = ictx->page;

            if (page) {

                BUG_ON(!PageLocked(page));

                unlock_page(page);

                ntfs_unmap_page(page);

            }

        }

    }

    kmem_cache_free(ntfs_index_ctx_cache, ictx);

    return;

}

​

/**

 * ntfs_index_lookup - find a key in an index and return its index entry

 * @key:    [IN] key for which to search in the index

 * @key_len:    [IN] length of @key in bytes

 * @ictx:   [IN/OUT] context describing the index and the returned entry

 *

 * Before calling ntfs_index_lookup(), @ictx must have been obtained from a

 * call to ntfs_index_ctx_get().

 *

 * Look for the @key in the index specified by the index lookup context @ictx.

 * ntfs_index_lookup() walks the contents of the index looking for the @key.

 *

 * If the @key is found in the index, 0 is returned and @ictx is setup to

 * describe the index entry containing the matching @key.  @ictx->entry is the

 * index entry and @ictx->data and @ictx->data_len are the index entry data and