1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * runlist.h - Defines for runlist handling in NTFS Linux kernel driver.
4  *	       Part of the Linux-NTFS project.
5  *
6  * Copyright (c) 2001-2005 Anton Altaparmakov
7  * Copyright (c) 2002 Richard Russon
8  */
9 
10 #ifndef _LINUX_NTFS_RUNLIST_H
11 #define _LINUX_NTFS_RUNLIST_H
12 
13 #include "types.h"
14 #include "layout.h"
15 #include "volume.h"
16 
17 /**
18  * runlist_element - in memory vcn to lcn mapping array element
19  * @vcn:	starting vcn of the current array element
20  * @lcn:	starting lcn of the current array element
21  * @length:	length in clusters of the current array element
22  *
23  * The last vcn (in fact the last vcn + 1) is reached when length == 0.
24  *
25  * When lcn == -1 this means that the count vcns starting at vcn are not
26  * physically allocated (i.e. this is a hole / data is sparse).
27  */
28 typedef struct {	/* In memory vcn to lcn mapping structure element. */
29 	VCN vcn;	/* vcn = Starting virtual cluster number. */
30 	LCN lcn;	/* lcn = Starting logical cluster number. */
31 	s64 length;	/* Run length in clusters. */
32 } runlist_element;
33 
34 /**
35  * runlist - in memory vcn to lcn mapping array including a read/write lock
36  * @rl:		pointer to an array of runlist elements
37  * @lock:	read/write spinlock for serializing access to @rl
38  *
39  */
40 typedef struct {
41 	runlist_element *rl;
42 	struct rw_semaphore lock;
43 } runlist;
44 
ntfs_init_runlist(runlist * rl)45 static inline void ntfs_init_runlist(runlist *rl)
46 {
47 	rl->rl = NULL;
48 	init_rwsem(&rl->lock);
49 }
50 
51 typedef enum {
52 	LCN_HOLE		= -1,	/* Keep this as highest value or die! */
53 	LCN_RL_NOT_MAPPED	= -2,
54 	LCN_ENOENT		= -3,
55 	LCN_ENOMEM		= -4,
56 	LCN_EIO			= -5,
57 } LCN_SPECIAL_VALUES;
58 
59 extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
60 		runlist_element *srl);
61 
62 extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
63 		const ATTR_RECORD *attr, runlist_element *old_rl);
64 
65 extern LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn);
66 
67 #ifdef NTFS_RW
68 
69 extern runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl,
70 		const VCN vcn);
71 
72 extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
73 		const runlist_element *rl, const VCN first_vcn,
74 		const VCN last_vcn);
75 
76 extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
77 		const int dst_len, const runlist_element *rl,
78 		const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn);
79 
80 extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol,
81 		runlist *const runlist, const s64 new_length);
82 
83 int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
84 		const VCN start, const s64 length);
85 
86 #endif /* NTFS_RW */
87 
88 #endif /* _LINUX_NTFS_RUNLIST_H */
89