1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation.  Part of the
  4 *		Linux-NTFS project.
  5 *
  6 * Copyright (c) 2004-2005 Anton Altaparmakov
  7 */
  8
  9#ifndef _LINUX_NTFS_LCNALLOC_H
 10#define _LINUX_NTFS_LCNALLOC_H
 11
 12#ifdef NTFS_RW
 13
 14#include <linux/fs.h>
 15
 16#include "attrib.h"
 17#include "types.h"
 18#include "inode.h"
 19#include "runlist.h"
 20#include "volume.h"
 21
 22typedef enum {
 23	FIRST_ZONE	= 0,	/* For sanity checking. */
 24	MFT_ZONE	= 0,	/* Allocate from $MFT zone. */
 25	DATA_ZONE	= 1,	/* Allocate from $DATA zone. */
 26	LAST_ZONE	= 1,	/* For sanity checking. */
 27} NTFS_CLUSTER_ALLOCATION_ZONES;
 28
 29extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
 30		const VCN start_vcn, const s64 count, const LCN start_lcn,
 31		const NTFS_CLUSTER_ALLOCATION_ZONES zone,
 32		const bool is_extension);
 33
 34extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
 35		s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);
 36
 37/**
 38 * ntfs_cluster_free - free clusters on an ntfs volume
 39 * @ni:		ntfs inode whose runlist describes the clusters to free
 40 * @start_vcn:	vcn in the runlist of @ni at which to start freeing clusters
 41 * @count:	number of clusters to free or -1 for all clusters
 42 * @ctx:	active attribute search context if present or NULL if not
 43 *
 44 * Free @count clusters starting at the cluster @start_vcn in the runlist
 45 * described by the ntfs inode @ni.
 46 *
 47 * If @count is -1, all clusters from @start_vcn to the end of the runlist are
 48 * deallocated.  Thus, to completely free all clusters in a runlist, use
 49 * @start_vcn = 0 and @count = -1.
 50 *
 51 * If @ctx is specified, it is an active search context of @ni and its base mft
 52 * record.  This is needed when ntfs_cluster_free() encounters unmapped runlist
 53 * fragments and allows their mapping.  If you do not have the mft record
 54 * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
 55 * the necessary mapping and unmapping.
 56 *
 57 * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
 58 * before returning.  Thus, @ctx will be left pointing to the same attribute on
 59 * return as on entry.  However, the actual pointers in @ctx may point to
 60 * different memory locations on return, so you must remember to reset any
 61 * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
 62 * you will probably want to do:
 63 *	m = ctx->mrec;
 64 *	a = ctx->attr;
 65 * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
 66 * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
 67 *
 68 * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
 69 * from the runlist or mark sparse the freed runs later.
 70 *
 71 * Return the number of deallocated clusters (not counting sparse ones) on
 72 * success and -errno on error.
 73 *
 74 * WARNING: If @ctx is supplied, regardless of whether success or failure is
 75 *	    returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
 76 *	    is no longer valid, i.e. you need to either call
 77 *	    ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
 78 *	    In that case PTR_ERR(@ctx->mrec) will give you the error code for
 79 *	    why the mapping of the old inode failed.
 80 *
 81 * Locking: - The runlist described by @ni must be locked for writing on entry
 82 *	      and is locked on return.  Note the runlist may be modified when
 83 *	      needed runlist fragments need to be mapped.
 84 *	    - The volume lcn bitmap must be unlocked on entry and is unlocked
 85 *	      on return.
 86 *	    - This function takes the volume lcn bitmap lock for writing and
 87 *	      modifies the bitmap contents.
 88 *	    - If @ctx is NULL, the base mft record of @ni must not be mapped on
 89 *	      entry and it will be left unmapped on return.
 90 *	    - If @ctx is not NULL, the base mft record must be mapped on entry
 91 *	      and it will be left mapped on return.
 92 */
 93static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
 94		s64 count, ntfs_attr_search_ctx *ctx)
 95{
 96	return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);
 97}
 98
 99extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
100		const runlist_element *rl);
101
102/**
103 * ntfs_cluster_free_from_rl - free clusters from runlist
104 * @vol:	mounted ntfs volume on which to free the clusters
105 * @rl:		runlist describing the clusters to free
106 *
107 * Free all the clusters described by the runlist @rl on the volume @vol.  In
108 * the case of an error being returned, at least some of the clusters were not
109 * freed.
110 *
111 * Return 0 on success and -errno on error.
112 *
113 * Locking: - This function takes the volume lcn bitmap lock for writing and
114 *	      modifies the bitmap contents.
115 *	    - The caller must have locked the runlist @rl for reading or
116 *	      writing.
117 */
118static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
119		const runlist_element *rl)
120{
121	int ret;
122
123	down_write(&vol->lcnbmp_lock);
124	ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
125	up_write(&vol->lcnbmp_lock);
126	return ret;
127}
128
129#endif /* NTFS_RW */
130
131#endif /* defined _LINUX_NTFS_LCNALLOC_H */