1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation. Part of the
4 * Linux-NTFS project.
5 *
6 * Copyright (c) 2004-2005 Anton Altaparmakov
7 */
8
9 #ifndef _LINUX_NTFS_LCNALLOC_H
10 #define _LINUX_NTFS_LCNALLOC_H
11
12 #ifdef NTFS_RW
13
14 #include <linux/fs.h>
15
16 #include "attrib.h"
17 #include "types.h"
18 #include "inode.h"
19 #include "runlist.h"
20 #include "volume.h"
21
22 typedef enum {
23 FIRST_ZONE = 0, /* For sanity checking. */
24 MFT_ZONE = 0, /* Allocate from $MFT zone. */
25 DATA_ZONE = 1, /* Allocate from $DATA zone. */
26 LAST_ZONE = 1, /* For sanity checking. */
27 } NTFS_CLUSTER_ALLOCATION_ZONES;
28
29 extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
30 const VCN start_vcn, const s64 count, const LCN start_lcn,
31 const NTFS_CLUSTER_ALLOCATION_ZONES zone,
32 const bool is_extension);
33
34 extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
35 s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);
36
37 /**
38 * ntfs_cluster_free - free clusters on an ntfs volume
39 * @ni: ntfs inode whose runlist describes the clusters to free
40 * @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
41 * @count: number of clusters to free or -1 for all clusters
42 * @ctx: active attribute search context if present or NULL if not
43 *
44 * Free @count clusters starting at the cluster @start_vcn in the runlist
45 * described by the ntfs inode @ni.
46 *
47 * If @count is -1, all clusters from @start_vcn to the end of the runlist are
48 * deallocated. Thus, to completely free all clusters in a runlist, use
49 * @start_vcn = 0 and @count = -1.
50 *
51 * If @ctx is specified, it is an active search context of @ni and its base mft
52 * record. This is needed when ntfs_cluster_free() encounters unmapped runlist
53 * fragments and allows their mapping. If you do not have the mft record
54 * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
55 * the necessary mapping and unmapping.
56 *
57 * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
58 * before returning. Thus, @ctx will be left pointing to the same attribute on
59 * return as on entry. However, the actual pointers in @ctx may point to
60 * different memory locations on return, so you must remember to reset any
61 * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
62 * you will probably want to do:
63 * m = ctx->mrec;
64 * a = ctx->attr;
65 * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
66 * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
67 *
68 * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
69 * from the runlist or mark sparse the freed runs later.
70 *
71 * Return the number of deallocated clusters (not counting sparse ones) on
72 * success and -errno on error.
73 *
74 * WARNING: If @ctx is supplied, regardless of whether success or failure is
75 * returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
76 * is no longer valid, i.e. you need to either call
77 * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
78 * In that case PTR_ERR(@ctx->mrec) will give you the error code for
79 * why the mapping of the old inode failed.
80 *
81 * Locking: - The runlist described by @ni must be locked for writing on entry
82 * and is locked on return. Note the runlist may be modified when
83 * needed runlist fragments need to be mapped.
84 * - The volume lcn bitmap must be unlocked on entry and is unlocked
85 * on return.
86 * - This function takes the volume lcn bitmap lock for writing and
87 * modifies the bitmap contents.
88 * - If @ctx is NULL, the base mft record of @ni must not be mapped on
89 * entry and it will be left unmapped on return.
90 * - If @ctx is not NULL, the base mft record must be mapped on entry
91 * and it will be left mapped on return.
92 */
93 static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
94 s64 count, ntfs_attr_search_ctx *ctx)
95 {
96 return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);
97 }
98
99 extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
100 const runlist_element *rl);
101
102 /**
103 * ntfs_cluster_free_from_rl - free clusters from runlist
104 * @vol: mounted ntfs volume on which to free the clusters
105 * @rl: runlist describing the clusters to free
106 *
107 * Free all the clusters described by the runlist @rl on the volume @vol. In
108 * the case of an error being returned, at least some of the clusters were not
109 * freed.
110 *
111 * Return 0 on success and -errno on error.
112 *
113 * Locking: - This function takes the volume lcn bitmap lock for writing and
114 * modifies the bitmap contents.
115 * - The caller must have locked the runlist @rl for reading or
116 * writing.
117 */
118 static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
119 const runlist_element *rl)
120 {
121 int ret;
122
123 down_write(&vol->lcnbmp_lock);
124 ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
125 up_write(&vol->lcnbmp_lock);
126 return ret;
127 }
128
129 #endif /* NTFS_RW */
130
131 #endif /* defined _LINUX_NTFS_LCNALLOC_H */