1/*
  2 * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation.  Part of the
  3 *		Linux-NTFS project.
  4 *
  5 * Copyright (c) 2004-2005 Anton Altaparmakov
  6 *
  7 * This program/include file is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU General Public License as published
  9 * by the Free Software Foundation; either version 2 of the License, or
 10 * (at your option) any later version.
 11 *
 12 * This program/include file is distributed in the hope that it will be
 13 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15 * GNU General Public License for more details.
 16 *
 17 * You should have received a copy of the GNU General Public License
 18 * along with this program (in the main directory of the Linux-NTFS
 19 * distribution in the file COPYING); if not, write to the Free Software
 20 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 21 */
 22
 23#ifndef _LINUX_NTFS_LCNALLOC_H
 24#define _LINUX_NTFS_LCNALLOC_H
 25
 26#ifdef NTFS_RW
 27
 28#include <linux/fs.h>
 29
 30#include "attrib.h"
 31#include "types.h"
 32#include "inode.h"
 33#include "runlist.h"
 34#include "volume.h"
 35
 36typedef enum {
 37	FIRST_ZONE	= 0,	/* For sanity checking. */
 38	MFT_ZONE	= 0,	/* Allocate from $MFT zone. */
 39	DATA_ZONE	= 1,	/* Allocate from $DATA zone. */
 40	LAST_ZONE	= 1,	/* For sanity checking. */
 41} NTFS_CLUSTER_ALLOCATION_ZONES;
 42
 43extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
 44		const VCN start_vcn, const s64 count, const LCN start_lcn,
 45		const NTFS_CLUSTER_ALLOCATION_ZONES zone,
 46		const bool is_extension);
 47
 48extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
 49		s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);
 50
 51/**
 52 * ntfs_cluster_free - free clusters on an ntfs volume
 53 * @ni:		ntfs inode whose runlist describes the clusters to free
 54 * @start_vcn:	vcn in the runlist of @ni at which to start freeing clusters
 55 * @count:	number of clusters to free or -1 for all clusters
 56 * @ctx:	active attribute search context if present or NULL if not
 57 *
 58 * Free @count clusters starting at the cluster @start_vcn in the runlist
 59 * described by the ntfs inode @ni.
 60 *
 61 * If @count is -1, all clusters from @start_vcn to the end of the runlist are
 62 * deallocated.  Thus, to completely free all clusters in a runlist, use
 63 * @start_vcn = 0 and @count = -1.
 64 *
 65 * If @ctx is specified, it is an active search context of @ni and its base mft
 66 * record.  This is needed when ntfs_cluster_free() encounters unmapped runlist
 67 * fragments and allows their mapping.  If you do not have the mft record
 68 * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
 69 * the necessary mapping and unmapping.
 70 *
 71 * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
 72 * before returning.  Thus, @ctx will be left pointing to the same attribute on
 73 * return as on entry.  However, the actual pointers in @ctx may point to
 74 * different memory locations on return, so you must remember to reset any
 75 * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
 76 * you will probably want to do:
 77 *	m = ctx->mrec;
 78 *	a = ctx->attr;
 79 * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
 80 * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
 81 *
 82 * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
 83 * from the runlist or mark sparse the freed runs later.
 84 *
 85 * Return the number of deallocated clusters (not counting sparse ones) on
 86 * success and -errno on error.
 87 *
 88 * WARNING: If @ctx is supplied, regardless of whether success or failure is
 89 *	    returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
 90 *	    is no longer valid, i.e. you need to either call
 91 *	    ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
 92 *	    In that case PTR_ERR(@ctx->mrec) will give you the error code for
 93 *	    why the mapping of the old inode failed.
 94 *
 95 * Locking: - The runlist described by @ni must be locked for writing on entry
 96 *	      and is locked on return.  Note the runlist may be modified when
 97 *	      needed runlist fragments need to be mapped.
 98 *	    - The volume lcn bitmap must be unlocked on entry and is unlocked
 99 *	      on return.
100 *	    - This function takes the volume lcn bitmap lock for writing and
101 *	      modifies the bitmap contents.
102 *	    - If @ctx is NULL, the base mft record of @ni must not be mapped on
103 *	      entry and it will be left unmapped on return.
104 *	    - If @ctx is not NULL, the base mft record must be mapped on entry
105 *	      and it will be left mapped on return.
106 */
107static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
108		s64 count, ntfs_attr_search_ctx *ctx)
109{
110	return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);
111}
112
113extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
114		const runlist_element *rl);
115
116/**
117 * ntfs_cluster_free_from_rl - free clusters from runlist
118 * @vol:	mounted ntfs volume on which to free the clusters
119 * @rl:		runlist describing the clusters to free
120 *
121 * Free all the clusters described by the runlist @rl on the volume @vol.  In
122 * the case of an error being returned, at least some of the clusters were not
123 * freed.
124 *
125 * Return 0 on success and -errno on error.
126 *
127 * Locking: - This function takes the volume lcn bitmap lock for writing and
128 *	      modifies the bitmap contents.
129 *	    - The caller must have locked the runlist @rl for reading or
130 *	      writing.
131 */
132static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
133		const runlist_element *rl)
134{
135	int ret;
136
137	down_write(&vol->lcnbmp_lock);
138	ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
139	up_write(&vol->lcnbmp_lock);
140	return ret;
141}
142
143#endif /* NTFS_RW */
144
145#endif /* defined _LINUX_NTFS_LCNALLOC_H */