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/*

 * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation.  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

 */

#ifndef _LINUX_NTFS_LCNALLOC_H

#define _LINUX_NTFS_LCNALLOC_H

#ifdef NTFS_RW

#include <linux/fs.h>

#include "attrib.h"

#include "types.h"

#include "inode.h"

#include "runlist.h"

#include "volume.h"

typedef enum {

        FIRST_ZONE      = 0,     /* For sanity checking. */

        MFT_ZONE        = 0,     /* Allocate from $MFT zone. */

        DATA_ZONE       = 1,    /* Allocate from $DATA zone. */

        LAST_ZONE       = 1,    /* For sanity checking. */

} NTFS_CLUSTER_ALLOCATION_ZONES;

extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,

                const VCN start_vcn, const s64 count, const LCN start_lcn,

                const NTFS_CLUSTER_ALLOCATION_ZONES zone,

                const bool is_extension);

extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,

                s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);

/**

 * ntfs_cluster_free - free clusters on an ntfs volume

 * @ni:         ntfs inode whose runlist describes the clusters to free

 * @start_vcn:  vcn in the runlist of @ni at which to start freeing clusters

 * @count:      number of clusters to free or -1 for all clusters

 * @ctx:        active attribute search context if present or NULL if not

 *

 * Free @count clusters starting at the cluster @start_vcn in the runlist

 * described by the ntfs inode @ni.

 *

 * If @count is -1, all clusters from @start_vcn to the end of the runlist are

 * deallocated.  Thus, to completely free all clusters in a runlist, use

 * @start_vcn = 0 and @count = -1.

 *

 * If @ctx is specified, it is an active search context of @ni and its base mft

 * record.  This is needed when ntfs_cluster_free() encounters unmapped runlist

 * fragments and allows their mapping.  If you do not have the mft record

 * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform

 * the necessary mapping and unmapping.

 *

 * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it

 * before returning.  Thus, @ctx will be left pointing to the same attribute on

 * return as on entry.  However, the actual pointers in @ctx may point to

 * different memory locations on return, so you must remember to reset any

 * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),

 * you will probably want to do:

 *      m = ctx->mrec;

 *      a = ctx->attr;

 * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that

 * you cache ctx->mrec in a variable @m of type MFT_RECORD *.

 *

 * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove

 * from the runlist or mark sparse the freed runs later.

 *

 * Return the number of deallocated clusters (not counting sparse ones) on

 * success and -errno on error.

 *

 * WARNING: If @ctx is supplied, regardless of whether success or failure is

 *          returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx

 *          is no longer valid, i.e. you need to either call

 *          ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.

 *          In that case PTR_ERR(@ctx->mrec) will give you the error code for

 *          why the mapping of the old inode failed.

 *

 * Locking: - The runlist described by @ni must be locked for writing on entry

 *            and is locked on return.  Note the runlist may be modified when

 *            needed runlist fragments need to be mapped.

 *          - The volume lcn bitmap must be unlocked on entry and is unlocked

 *            on return.

 *          - This function takes the volume lcn bitmap lock for writing and

 *            modifies the bitmap contents.

 *          - If @ctx is NULL, the base mft record of @ni must not be mapped on

 *            entry and it will be left unmapped on return.

 *          - If @ctx is not NULL, the base mft record must be mapped on entry

 *            and it will be left mapped on return.

 */

static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,

                s64 count, ntfs_attr_search_ctx *ctx)

{

        return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);

}

extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,

                const runlist_element *rl);

/**

 * ntfs_cluster_free_from_rl - free clusters from runlist

 * @vol:        mounted ntfs volume on which to free the clusters

 * @rl:         runlist describing the clusters to free

 *

 * Free all the clusters described by the runlist @rl on the volume @vol.  In

 * the case of an error being returned, at least some of the clusters were not

 * freed.

 *

 * Return 0 on success and -errno on error.

 *

 * Locking: - This function takes the volume lcn bitmap lock for writing and

 *            modifies the bitmap contents.

 *          - The caller must have locked the runlist @rl for reading or

 *            writing.

 */

static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,

                const runlist_element *rl)

{

        int ret;

        down_write(&vol->lcnbmp_lock);

        ret = ntfs_cluster_free_from_rl_nolock(vol, rl);

        up_write(&vol->lcnbmp_lock);

        return ret;

}

#endif /* NTFS_RW */

#endif /* defined _LINUX_NTFS_LCNALLOC_H */