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 
36 typedef 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 
43 extern 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 
48 extern 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  */
ntfs_cluster_free(ntfs_inode * ni,const VCN start_vcn,s64 count,ntfs_attr_search_ctx * ctx)107 static 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 
113 extern 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  */
ntfs_cluster_free_from_rl(ntfs_volume * vol,const runlist_element * rl)132 static 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 */
146