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, is_rollback: 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(sem: &vol->lcnbmp_lock); |
124 | ret = ntfs_cluster_free_from_rl_nolock(vol, rl); |
125 | up_write(sem: &vol->lcnbmp_lock); |
126 | return ret; |
127 | } |
128 | |
129 | #endif /* NTFS_RW */ |
130 | |
131 | #endif /* defined _LINUX_NTFS_LCNALLOC_H */ |
132 | |