aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ntfs/lcnalloc.h
blob: 2adb04316941017109ba85b893d504d06b230be0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
/*
 * 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 */