Root/
1 | /* |
2 | * bitmap.c - NTFS kernel bitmap handling. Part of the Linux-NTFS project. |
3 | * |
4 | * Copyright (c) 2004-2005 Anton Altaparmakov |
5 | * |
6 | * This program/include file is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public License as published |
8 | * by the Free Software Foundation; either version 2 of the License, or |
9 | * (at your option) any later version. |
10 | * |
11 | * This program/include file is distributed in the hope that it will be |
12 | * useful, but WITHOUT ANY WARRANTY; without even the implied warranty |
13 | * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | * GNU General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public License |
17 | * along with this program (in the main directory of the Linux-NTFS |
18 | * distribution in the file COPYING); if not, write to the Free Software |
19 | * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
20 | */ |
21 | |
22 | #ifdef NTFS_RW |
23 | |
24 | #include <linux/pagemap.h> |
25 | |
26 | #include "bitmap.h" |
27 | #include "debug.h" |
28 | #include "aops.h" |
29 | #include "ntfs.h" |
30 | |
31 | /** |
32 | * __ntfs_bitmap_set_bits_in_run - set a run of bits in a bitmap to a value |
33 | * @vi: vfs inode describing the bitmap |
34 | * @start_bit: first bit to set |
35 | * @count: number of bits to set |
36 | * @value: value to set the bits to (i.e. 0 or 1) |
37 | * @is_rollback: if 'true' this is a rollback operation |
38 | * |
39 | * Set @count bits starting at bit @start_bit in the bitmap described by the |
40 | * vfs inode @vi to @value, where @value is either 0 or 1. |
41 | * |
42 | * @is_rollback should always be 'false', it is for internal use to rollback |
43 | * errors. You probably want to use ntfs_bitmap_set_bits_in_run() instead. |
44 | * |
45 | * Return 0 on success and -errno on error. |
46 | */ |
47 | int __ntfs_bitmap_set_bits_in_run(struct inode *vi, const s64 start_bit, |
48 | const s64 count, const u8 value, const bool is_rollback) |
49 | { |
50 | s64 cnt = count; |
51 | pgoff_t index, end_index; |
52 | struct address_space *mapping; |
53 | struct page *page; |
54 | u8 *kaddr; |
55 | int pos, len; |
56 | u8 bit; |
57 | |
58 | BUG_ON(!vi); |
59 | ntfs_debug("Entering for i_ino 0x%lx, start_bit 0x%llx, count 0x%llx, " |
60 | "value %u.%s", vi->i_ino, (unsigned long long)start_bit, |
61 | (unsigned long long)cnt, (unsigned int)value, |
62 | is_rollback ? " (rollback)" : ""); |
63 | BUG_ON(start_bit < 0); |
64 | BUG_ON(cnt < 0); |
65 | BUG_ON(value > 1); |
66 | /* |
67 | * Calculate the indices for the pages containing the first and last |
68 | * bits, i.e. @start_bit and @start_bit + @cnt - 1, respectively. |
69 | */ |
70 | index = start_bit >> (3 + PAGE_CACHE_SHIFT); |
71 | end_index = (start_bit + cnt - 1) >> (3 + PAGE_CACHE_SHIFT); |
72 | |
73 | /* Get the page containing the first bit (@start_bit). */ |
74 | mapping = vi->i_mapping; |
75 | page = ntfs_map_page(mapping, index); |
76 | if (IS_ERR(page)) { |
77 | if (!is_rollback) |
78 | ntfs_error(vi->i_sb, "Failed to map first page (error " |
79 | "%li), aborting.", PTR_ERR(page)); |
80 | return PTR_ERR(page); |
81 | } |
82 | kaddr = page_address(page); |
83 | |
84 | /* Set @pos to the position of the byte containing @start_bit. */ |
85 | pos = (start_bit >> 3) & ~PAGE_CACHE_MASK; |
86 | |
87 | /* Calculate the position of @start_bit in the first byte. */ |
88 | bit = start_bit & 7; |
89 | |
90 | /* If the first byte is partial, modify the appropriate bits in it. */ |
91 | if (bit) { |
92 | u8 *byte = kaddr + pos; |
93 | while ((bit & 7) && cnt) { |
94 | cnt--; |
95 | if (value) |
96 | *byte |= 1 << bit++; |
97 | else |
98 | *byte &= ~(1 << bit++); |
99 | } |
100 | /* If we are done, unmap the page and return success. */ |
101 | if (!cnt) |
102 | goto done; |
103 | |
104 | /* Update @pos to the new position. */ |
105 | pos++; |
106 | } |
107 | /* |
108 | * Depending on @value, modify all remaining whole bytes in the page up |
109 | * to @cnt. |
110 | */ |
111 | len = min_t(s64, cnt >> 3, PAGE_CACHE_SIZE - pos); |
112 | memset(kaddr + pos, value ? 0xff : 0, len); |
113 | cnt -= len << 3; |
114 | |
115 | /* Update @len to point to the first not-done byte in the page. */ |
116 | if (cnt < 8) |
117 | len += pos; |
118 | |
119 | /* If we are not in the last page, deal with all subsequent pages. */ |
120 | while (index < end_index) { |
121 | BUG_ON(cnt <= 0); |
122 | |
123 | /* Update @index and get the next page. */ |
124 | flush_dcache_page(page); |
125 | set_page_dirty(page); |
126 | ntfs_unmap_page(page); |
127 | page = ntfs_map_page(mapping, ++index); |
128 | if (IS_ERR(page)) |
129 | goto rollback; |
130 | kaddr = page_address(page); |
131 | /* |
132 | * Depending on @value, modify all remaining whole bytes in the |
133 | * page up to @cnt. |
134 | */ |
135 | len = min_t(s64, cnt >> 3, PAGE_CACHE_SIZE); |
136 | memset(kaddr, value ? 0xff : 0, len); |
137 | cnt -= len << 3; |
138 | } |
139 | /* |
140 | * The currently mapped page is the last one. If the last byte is |
141 | * partial, modify the appropriate bits in it. Note, @len is the |
142 | * position of the last byte inside the page. |
143 | */ |
144 | if (cnt) { |
145 | u8 *byte; |
146 | |
147 | BUG_ON(cnt > 7); |
148 | |
149 | bit = cnt; |
150 | byte = kaddr + len; |
151 | while (bit--) { |
152 | if (value) |
153 | *byte |= 1 << bit; |
154 | else |
155 | *byte &= ~(1 << bit); |
156 | } |
157 | } |
158 | done: |
159 | /* We are done. Unmap the page and return success. */ |
160 | flush_dcache_page(page); |
161 | set_page_dirty(page); |
162 | ntfs_unmap_page(page); |
163 | ntfs_debug("Done."); |
164 | return 0; |
165 | rollback: |
166 | /* |
167 | * Current state: |
168 | * - no pages are mapped |
169 | * - @count - @cnt is the number of bits that have been modified |
170 | */ |
171 | if (is_rollback) |
172 | return PTR_ERR(page); |
173 | if (count != cnt) |
174 | pos = __ntfs_bitmap_set_bits_in_run(vi, start_bit, count - cnt, |
175 | value ? 0 : 1, true); |
176 | else |
177 | pos = 0; |
178 | if (!pos) { |
179 | /* Rollback was successful. */ |
180 | ntfs_error(vi->i_sb, "Failed to map subsequent page (error " |
181 | "%li), aborting.", PTR_ERR(page)); |
182 | } else { |
183 | /* Rollback failed. */ |
184 | ntfs_error(vi->i_sb, "Failed to map subsequent page (error " |
185 | "%li) and rollback failed (error %i). " |
186 | "Aborting and leaving inconsistent metadata. " |
187 | "Unmount and run chkdsk.", PTR_ERR(page), pos); |
188 | NVolSetErrors(NTFS_SB(vi->i_sb)); |
189 | } |
190 | return PTR_ERR(page); |
191 | } |
192 | |
193 | #endif /* NTFS_RW */ |
194 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9