Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/hfsplus/bitmap.c | |
3 | * | |
4 | * Copyright (C) 2001 | |
5 | * Brad Boyer (flar@allandria.com) | |
6 | * (C) 2003 Ardis Technologies <roman@ardistech.com> | |
7 | * | |
8 | * Handling of allocation file | |
9 | */ | |
10 | ||
11 | #include <linux/pagemap.h> | |
12 | ||
13 | #include "hfsplus_fs.h" | |
14 | #include "hfsplus_raw.h" | |
15 | ||
16 | #define PAGE_CACHE_BITS (PAGE_CACHE_SIZE * 8) | |
17 | ||
2753cc28 AS |
18 | int hfsplus_block_allocate(struct super_block *sb, u32 size, |
19 | u32 offset, u32 *max) | |
1da177e4 | 20 | { |
dd73a01a | 21 | struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); |
1da177e4 LT |
22 | struct page *page; |
23 | struct address_space *mapping; | |
24 | __be32 *pptr, *curr, *end; | |
25 | u32 mask, start, len, n; | |
26 | __be32 val; | |
27 | int i; | |
28 | ||
29 | len = *max; | |
30 | if (!len) | |
31 | return size; | |
32 | ||
33 | dprint(DBG_BITMAP, "block_allocate: %u,%u,%u\n", size, offset, len); | |
dd73a01a CH |
34 | mutex_lock(&sbi->alloc_mutex); |
35 | mapping = sbi->alloc_file->i_mapping; | |
090d2b18 | 36 | page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, NULL); |
649f1ee6 ES |
37 | if (IS_ERR(page)) { |
38 | start = size; | |
39 | goto out; | |
40 | } | |
1da177e4 LT |
41 | pptr = kmap(page); |
42 | curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32; | |
43 | i = offset % 32; | |
44 | offset &= ~(PAGE_CACHE_BITS - 1); | |
45 | if ((size ^ offset) / PAGE_CACHE_BITS) | |
46 | end = pptr + PAGE_CACHE_BITS / 32; | |
47 | else | |
48 | end = pptr + ((size + 31) & (PAGE_CACHE_BITS - 1)) / 32; | |
49 | ||
50 | /* scan the first partial u32 for zero bits */ | |
51 | val = *curr; | |
52 | if (~val) { | |
53 | n = be32_to_cpu(val); | |
54 | mask = (1U << 31) >> i; | |
55 | for (; i < 32; mask >>= 1, i++) { | |
56 | if (!(n & mask)) | |
57 | goto found; | |
58 | } | |
59 | } | |
60 | curr++; | |
61 | ||
62 | /* scan complete u32s for the first zero bit */ | |
63 | while (1) { | |
64 | while (curr < end) { | |
65 | val = *curr; | |
66 | if (~val) { | |
67 | n = be32_to_cpu(val); | |
68 | mask = 1 << 31; | |
69 | for (i = 0; i < 32; mask >>= 1, i++) { | |
70 | if (!(n & mask)) | |
71 | goto found; | |
72 | } | |
73 | } | |
74 | curr++; | |
75 | } | |
76 | kunmap(page); | |
77 | offset += PAGE_CACHE_BITS; | |
78 | if (offset >= size) | |
79 | break; | |
090d2b18 PE |
80 | page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, |
81 | NULL); | |
649f1ee6 ES |
82 | if (IS_ERR(page)) { |
83 | start = size; | |
84 | goto out; | |
85 | } | |
1da177e4 LT |
86 | curr = pptr = kmap(page); |
87 | if ((size ^ offset) / PAGE_CACHE_BITS) | |
88 | end = pptr + PAGE_CACHE_BITS / 32; | |
89 | else | |
90 | end = pptr + ((size + 31) & (PAGE_CACHE_BITS - 1)) / 32; | |
91 | } | |
92 | dprint(DBG_BITMAP, "bitmap full\n"); | |
93 | start = size; | |
94 | goto out; | |
95 | ||
96 | found: | |
97 | start = offset + (curr - pptr) * 32 + i; | |
98 | if (start >= size) { | |
99 | dprint(DBG_BITMAP, "bitmap full\n"); | |
100 | goto out; | |
101 | } | |
102 | /* do any partial u32 at the start */ | |
103 | len = min(size - start, len); | |
104 | while (1) { | |
105 | n |= mask; | |
106 | if (++i >= 32) | |
107 | break; | |
108 | mask >>= 1; | |
109 | if (!--len || n & mask) | |
110 | goto done; | |
111 | } | |
112 | if (!--len) | |
113 | goto done; | |
114 | *curr++ = cpu_to_be32(n); | |
115 | /* do full u32s */ | |
116 | while (1) { | |
117 | while (curr < end) { | |
118 | n = be32_to_cpu(*curr); | |
119 | if (len < 32) | |
120 | goto last; | |
121 | if (n) { | |
122 | len = 32; | |
123 | goto last; | |
124 | } | |
125 | *curr++ = cpu_to_be32(0xffffffff); | |
126 | len -= 32; | |
127 | } | |
128 | set_page_dirty(page); | |
129 | kunmap(page); | |
130 | offset += PAGE_CACHE_BITS; | |
090d2b18 PE |
131 | page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, |
132 | NULL); | |
649f1ee6 ES |
133 | if (IS_ERR(page)) { |
134 | start = size; | |
135 | goto out; | |
136 | } | |
1da177e4 LT |
137 | pptr = kmap(page); |
138 | curr = pptr; | |
139 | end = pptr + PAGE_CACHE_BITS / 32; | |
140 | } | |
141 | last: | |
142 | /* do any partial u32 at end */ | |
143 | mask = 1U << 31; | |
144 | for (i = 0; i < len; i++) { | |
145 | if (n & mask) | |
146 | break; | |
147 | n |= mask; | |
148 | mask >>= 1; | |
149 | } | |
150 | done: | |
151 | *curr = cpu_to_be32(n); | |
152 | set_page_dirty(page); | |
153 | kunmap(page); | |
154 | *max = offset + (curr - pptr) * 32 + i - start; | |
dd73a01a | 155 | sbi->free_blocks -= *max; |
1da177e4 LT |
156 | sb->s_dirt = 1; |
157 | dprint(DBG_BITMAP, "-> %u,%u\n", start, *max); | |
158 | out: | |
dd73a01a | 159 | mutex_unlock(&sbi->alloc_mutex); |
1da177e4 LT |
160 | return start; |
161 | } | |
162 | ||
163 | int hfsplus_block_free(struct super_block *sb, u32 offset, u32 count) | |
164 | { | |
dd73a01a | 165 | struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); |
1da177e4 LT |
166 | struct page *page; |
167 | struct address_space *mapping; | |
168 | __be32 *pptr, *curr, *end; | |
169 | u32 mask, len, pnr; | |
170 | int i; | |
171 | ||
172 | /* is there any actual work to be done? */ | |
173 | if (!count) | |
174 | return 0; | |
175 | ||
176 | dprint(DBG_BITMAP, "block_free: %u,%u\n", offset, count); | |
177 | /* are all of the bits in range? */ | |
dd73a01a | 178 | if ((offset + count) > sbi->total_blocks) |
1da177e4 LT |
179 | return -2; |
180 | ||
dd73a01a CH |
181 | mutex_lock(&sbi->alloc_mutex); |
182 | mapping = sbi->alloc_file->i_mapping; | |
1da177e4 | 183 | pnr = offset / PAGE_CACHE_BITS; |
090d2b18 | 184 | page = read_mapping_page(mapping, pnr, NULL); |
1da177e4 LT |
185 | pptr = kmap(page); |
186 | curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32; | |
187 | end = pptr + PAGE_CACHE_BITS / 32; | |
188 | len = count; | |
189 | ||
190 | /* do any partial u32 at the start */ | |
191 | i = offset % 32; | |
192 | if (i) { | |
193 | int j = 32 - i; | |
194 | mask = 0xffffffffU << j; | |
195 | if (j > count) { | |
196 | mask |= 0xffffffffU >> (i + count); | |
197 | *curr++ &= cpu_to_be32(mask); | |
198 | goto out; | |
199 | } | |
200 | *curr++ &= cpu_to_be32(mask); | |
201 | count -= j; | |
202 | } | |
203 | ||
204 | /* do full u32s */ | |
205 | while (1) { | |
206 | while (curr < end) { | |
207 | if (count < 32) | |
208 | goto done; | |
209 | *curr++ = 0; | |
210 | count -= 32; | |
211 | } | |
212 | if (!count) | |
213 | break; | |
214 | set_page_dirty(page); | |
215 | kunmap(page); | |
090d2b18 | 216 | page = read_mapping_page(mapping, ++pnr, NULL); |
1da177e4 LT |
217 | pptr = kmap(page); |
218 | curr = pptr; | |
219 | end = pptr + PAGE_CACHE_BITS / 32; | |
220 | } | |
221 | done: | |
222 | /* do any partial u32 at end */ | |
223 | if (count) { | |
224 | mask = 0xffffffffU >> count; | |
225 | *curr &= cpu_to_be32(mask); | |
226 | } | |
227 | out: | |
228 | set_page_dirty(page); | |
229 | kunmap(page); | |
dd73a01a | 230 | sbi->free_blocks += len; |
1da177e4 | 231 | sb->s_dirt = 1; |
dd73a01a | 232 | mutex_unlock(&sbi->alloc_mutex); |
1da177e4 LT |
233 | |
234 | return 0; | |
235 | } |