1 /*
2  * runlist.h - Defines for runlist handling in NTFS Linux kernel driver.
3  *	       Part of the Linux-NTFS project.
4  *
5  * Copyright (c) 2001-2005 Anton Altaparmakov
6  * Copyright (c) 2002 Richard Russon
7  *
8  * This program/include file is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as published
10  * by the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program/include file is distributed in the hope that it will be
14  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
15  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program (in the main directory of the Linux-NTFS
20  * distribution in the file COPYING); if not, write to the Free Software
21  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22  */
23 
24 #ifndef _LINUX_NTFS_RUNLIST_H
25 #define _LINUX_NTFS_RUNLIST_H
26 
27 #include "types.h"
28 #include "layout.h"
29 #include "volume.h"
30 
31 /**
32  * runlist_element - in memory vcn to lcn mapping array element
33  * @vcn:	starting vcn of the current array element
34  * @lcn:	starting lcn of the current array element
35  * @length:	length in clusters of the current array element
36  *
37  * The last vcn (in fact the last vcn + 1) is reached when length == 0.
38  *
39  * When lcn == -1 this means that the count vcns starting at vcn are not
40  * physically allocated (i.e. this is a hole / data is sparse).
41  */
42 typedef struct {	/* In memory vcn to lcn mapping structure element. */
43 	VCN vcn;	/* vcn = Starting virtual cluster number. */
44 	LCN lcn;	/* lcn = Starting logical cluster number. */
45 	s64 length;	/* Run length in clusters. */
46 } runlist_element;
47 
48 /**
49  * runlist - in memory vcn to lcn mapping array including a read/write lock
50  * @rl:		pointer to an array of runlist elements
51  * @lock:	read/write spinlock for serializing access to @rl
52  *
53  */
54 typedef struct {
55 	runlist_element *rl;
56 	struct rw_semaphore lock;
57 } runlist;
58 
ntfs_init_runlist(runlist * rl)59 static inline void ntfs_init_runlist(runlist *rl)
60 {
61 	rl->rl = NULL;
62 	init_rwsem(&rl->lock);
63 }
64 
65 typedef enum {
66 	LCN_HOLE		= -1,	/* Keep this as highest value or die! */
67 	LCN_RL_NOT_MAPPED	= -2,
68 	LCN_ENOENT		= -3,
69 	LCN_ENOMEM		= -4,
70 	LCN_EIO			= -5,
71 } LCN_SPECIAL_VALUES;
72 
73 extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
74 		runlist_element *srl);
75 
76 extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
77 		const ATTR_RECORD *attr, runlist_element *old_rl);
78 
79 extern LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn);
80 
81 #ifdef NTFS_RW
82 
83 extern runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl,
84 		const VCN vcn);
85 
86 extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
87 		const runlist_element *rl, const VCN first_vcn,
88 		const VCN last_vcn);
89 
90 extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
91 		const int dst_len, const runlist_element *rl,
92 		const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn);
93 
94 extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol,
95 		runlist *const runlist, const s64 new_length);
96 
97 int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
98 		const VCN start, const s64 length);
99 
100 #endif /* NTFS_RW */
101 
102 #endif /* _LINUX_NTFS_RUNLIST_H */
103