/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* lcnalloc.h - Exports for NTFS kernel cluster (de)allocation. Part of the
* Linux-NTFS project.
*
* Copyright (c) 2004-2005 Anton Altaparmakov
*/
#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 */
