diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/hfsplus/bitmap.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/hfsplus/bitmap.c')
-rw-r--r-- | fs/hfsplus/bitmap.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/fs/hfsplus/bitmap.c b/fs/hfsplus/bitmap.c new file mode 100644 index 00000000000..c7d316455fa --- /dev/null +++ b/fs/hfsplus/bitmap.c | |||
@@ -0,0 +1,221 @@ | |||
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 | |||
18 | int hfsplus_block_allocate(struct super_block *sb, u32 size, u32 offset, u32 *max) | ||
19 | { | ||
20 | struct page *page; | ||
21 | struct address_space *mapping; | ||
22 | __be32 *pptr, *curr, *end; | ||
23 | u32 mask, start, len, n; | ||
24 | __be32 val; | ||
25 | int i; | ||
26 | |||
27 | len = *max; | ||
28 | if (!len) | ||
29 | return size; | ||
30 | |||
31 | dprint(DBG_BITMAP, "block_allocate: %u,%u,%u\n", size, offset, len); | ||
32 | down(&HFSPLUS_SB(sb).alloc_file->i_sem); | ||
33 | mapping = HFSPLUS_SB(sb).alloc_file->i_mapping; | ||
34 | page = read_cache_page(mapping, offset / PAGE_CACHE_BITS, | ||
35 | (filler_t *)mapping->a_ops->readpage, NULL); | ||
36 | pptr = kmap(page); | ||
37 | curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32; | ||
38 | i = offset % 32; | ||
39 | offset &= ~(PAGE_CACHE_BITS - 1); | ||
40 | if ((size ^ offset) / PAGE_CACHE_BITS) | ||
41 | end = pptr + PAGE_CACHE_BITS / 32; | ||
42 | else | ||
43 | end = pptr + ((size + 31) & (PAGE_CACHE_BITS - 1)) / 32; | ||
44 | |||
45 | /* scan the first partial u32 for zero bits */ | ||
46 | val = *curr; | ||
47 | if (~val) { | ||
48 | n = be32_to_cpu(val); | ||
49 | mask = (1U << 31) >> i; | ||
50 | for (; i < 32; mask >>= 1, i++) { | ||
51 | if (!(n & mask)) | ||
52 | goto found; | ||
53 | } | ||
54 | } | ||
55 | curr++; | ||
56 | |||
57 | /* scan complete u32s for the first zero bit */ | ||
58 | while (1) { | ||
59 | while (curr < end) { | ||
60 | val = *curr; | ||
61 | if (~val) { | ||
62 | n = be32_to_cpu(val); | ||
63 | mask = 1 << 31; | ||
64 | for (i = 0; i < 32; mask >>= 1, i++) { | ||
65 | if (!(n & mask)) | ||
66 | goto found; | ||
67 | } | ||
68 | } | ||
69 | curr++; | ||
70 | } | ||
71 | kunmap(page); | ||
72 | offset += PAGE_CACHE_BITS; | ||
73 | if (offset >= size) | ||
74 | break; | ||
75 | page = read_cache_page(mapping, offset / PAGE_CACHE_BITS, | ||
76 | (filler_t *)mapping->a_ops->readpage, NULL); | ||
77 | curr = pptr = kmap(page); | ||
78 | if ((size ^ offset) / PAGE_CACHE_BITS) | ||
79 | end = pptr + PAGE_CACHE_BITS / 32; | ||
80 | else | ||
81 | end = pptr + ((size + 31) & (PAGE_CACHE_BITS - 1)) / 32; | ||
82 | } | ||
83 | dprint(DBG_BITMAP, "bitmap full\n"); | ||
84 | start = size; | ||
85 | goto out; | ||
86 | |||
87 | found: | ||
88 | start = offset + (curr - pptr) * 32 + i; | ||
89 | if (start >= size) { | ||
90 | dprint(DBG_BITMAP, "bitmap full\n"); | ||
91 | goto out; | ||
92 | } | ||
93 | /* do any partial u32 at the start */ | ||
94 | len = min(size - start, len); | ||
95 | while (1) { | ||
96 | n |= mask; | ||
97 | if (++i >= 32) | ||
98 | break; | ||
99 | mask >>= 1; | ||
100 | if (!--len || n & mask) | ||
101 | goto done; | ||
102 | } | ||
103 | if (!--len) | ||
104 | goto done; | ||
105 | *curr++ = cpu_to_be32(n); | ||
106 | /* do full u32s */ | ||
107 | while (1) { | ||
108 | while (curr < end) { | ||
109 | n = be32_to_cpu(*curr); | ||
110 | if (len < 32) | ||
111 | goto last; | ||
112 | if (n) { | ||
113 | len = 32; | ||
114 | goto last; | ||
115 | } | ||
116 | *curr++ = cpu_to_be32(0xffffffff); | ||
117 | len -= 32; | ||
118 | } | ||
119 | set_page_dirty(page); | ||
120 | kunmap(page); | ||
121 | offset += PAGE_CACHE_BITS; | ||
122 | page = read_cache_page(mapping, offset / PAGE_CACHE_BITS, | ||
123 | (filler_t *)mapping->a_ops->readpage, NULL); | ||
124 | pptr = kmap(page); | ||
125 | curr = pptr; | ||
126 | end = pptr + PAGE_CACHE_BITS / 32; | ||
127 | } | ||
128 | last: | ||
129 | /* do any partial u32 at end */ | ||
130 | mask = 1U << 31; | ||
131 | for (i = 0; i < len; i++) { | ||
132 | if (n & mask) | ||
133 | break; | ||
134 | n |= mask; | ||
135 | mask >>= 1; | ||
136 | } | ||
137 | done: | ||
138 | *curr = cpu_to_be32(n); | ||
139 | set_page_dirty(page); | ||
140 | kunmap(page); | ||
141 | *max = offset + (curr - pptr) * 32 + i - start; | ||
142 | HFSPLUS_SB(sb).free_blocks -= *max; | ||
143 | sb->s_dirt = 1; | ||
144 | dprint(DBG_BITMAP, "-> %u,%u\n", start, *max); | ||
145 | out: | ||
146 | up(&HFSPLUS_SB(sb).alloc_file->i_sem); | ||
147 | return start; | ||
148 | } | ||
149 | |||
150 | int hfsplus_block_free(struct super_block *sb, u32 offset, u32 count) | ||
151 | { | ||
152 | struct page *page; | ||
153 | struct address_space *mapping; | ||
154 | __be32 *pptr, *curr, *end; | ||
155 | u32 mask, len, pnr; | ||
156 | int i; | ||
157 | |||
158 | /* is there any actual work to be done? */ | ||
159 | if (!count) | ||
160 | return 0; | ||
161 | |||
162 | dprint(DBG_BITMAP, "block_free: %u,%u\n", offset, count); | ||
163 | /* are all of the bits in range? */ | ||
164 | if ((offset + count) > HFSPLUS_SB(sb).total_blocks) | ||
165 | return -2; | ||
166 | |||
167 | down(&HFSPLUS_SB(sb).alloc_file->i_sem); | ||
168 | mapping = HFSPLUS_SB(sb).alloc_file->i_mapping; | ||
169 | pnr = offset / PAGE_CACHE_BITS; | ||
170 | page = read_cache_page(mapping, pnr, (filler_t *)mapping->a_ops->readpage, NULL); | ||
171 | pptr = kmap(page); | ||
172 | curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32; | ||
173 | end = pptr + PAGE_CACHE_BITS / 32; | ||
174 | len = count; | ||
175 | |||
176 | /* do any partial u32 at the start */ | ||
177 | i = offset % 32; | ||
178 | if (i) { | ||
179 | int j = 32 - i; | ||
180 | mask = 0xffffffffU << j; | ||
181 | if (j > count) { | ||
182 | mask |= 0xffffffffU >> (i + count); | ||
183 | *curr++ &= cpu_to_be32(mask); | ||
184 | goto out; | ||
185 | } | ||
186 | *curr++ &= cpu_to_be32(mask); | ||
187 | count -= j; | ||
188 | } | ||
189 | |||
190 | /* do full u32s */ | ||
191 | while (1) { | ||
192 | while (curr < end) { | ||
193 | if (count < 32) | ||
194 | goto done; | ||
195 | *curr++ = 0; | ||
196 | count -= 32; | ||
197 | } | ||
198 | if (!count) | ||
199 | break; | ||
200 | set_page_dirty(page); | ||
201 | kunmap(page); | ||
202 | page = read_cache_page(mapping, ++pnr, (filler_t *)mapping->a_ops->readpage, NULL); | ||
203 | pptr = kmap(page); | ||
204 | curr = pptr; | ||
205 | end = pptr + PAGE_CACHE_BITS / 32; | ||
206 | } | ||
207 | done: | ||
208 | /* do any partial u32 at end */ | ||
209 | if (count) { | ||
210 | mask = 0xffffffffU >> count; | ||
211 | *curr &= cpu_to_be32(mask); | ||
212 | } | ||
213 | out: | ||
214 | set_page_dirty(page); | ||
215 | kunmap(page); | ||
216 | HFSPLUS_SB(sb).free_blocks += len; | ||
217 | sb->s_dirt = 1; | ||
218 | up(&HFSPLUS_SB(sb).alloc_file->i_sem); | ||
219 | |||
220 | return 0; | ||
221 | } | ||