2 * bitmap.c - NTFS kernel bitmap handling. Part of the Linux-NTFS project.
4 * Copyright (c) 2004-2005 Anton Altaparmakov
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.
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.
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
24 #include <linux/pagemap.h>
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
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.
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.
45 * Return 0 on success and -errno on error.
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
)
51 pgoff_t index
, end_index
;
52 struct address_space
*mapping
;
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);
67 * Calculate the indices for the pages containing the first and last
68 * bits, i.e. @start_bit and @start_bit + @cnt - 1, respectively.
70 index
= start_bit
>> (3 + PAGE_SHIFT
);
71 end_index
= (start_bit
+ cnt
- 1) >> (3 + PAGE_SHIFT
);
73 /* Get the page containing the first bit (@start_bit). */
74 mapping
= vi
->i_mapping
;
75 page
= ntfs_map_page(mapping
, index
);
78 ntfs_error(vi
->i_sb
, "Failed to map first page (error "
79 "%li), aborting.", PTR_ERR(page
));
82 kaddr
= page_address(page
);
84 /* Set @pos to the position of the byte containing @start_bit. */
85 pos
= (start_bit
>> 3) & ~PAGE_MASK
;
87 /* Calculate the position of @start_bit in the first byte. */
90 /* If the first byte is partial, modify the appropriate bits in it. */
92 u8
*byte
= kaddr
+ pos
;
93 while ((bit
& 7) && cnt
) {
98 *byte
&= ~(1 << bit
++);
100 /* If we are done, unmap the page and return success. */
104 /* Update @pos to the new position. */
108 * Depending on @value, modify all remaining whole bytes in the page up
111 len
= min_t(s64
, cnt
>> 3, PAGE_SIZE
- pos
);
112 memset(kaddr
+ pos
, value
? 0xff : 0, len
);
115 /* Update @len to point to the first not-done byte in the page. */
119 /* If we are not in the last page, deal with all subsequent pages. */
120 while (index
< end_index
) {
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
);
130 kaddr
= page_address(page
);
132 * Depending on @value, modify all remaining whole bytes in the
135 len
= min_t(s64
, cnt
>> 3, PAGE_SIZE
);
136 memset(kaddr
, value
? 0xff : 0, len
);
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.
155 *byte
&= ~(1 << bit
);
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
);
168 * - no pages are mapped
169 * - @count - @cnt is the number of bits that have been modified
172 return PTR_ERR(page
);
174 pos
= __ntfs_bitmap_set_bits_in_run(vi
, start_bit
, count
- cnt
,
175 value
? 0 : 1, true);
179 /* Rollback was successful. */
180 ntfs_error(vi
->i_sb
, "Failed to map subsequent page (error "
181 "%li), aborting.", PTR_ERR(page
));
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
));
190 return PTR_ERR(page
);
This page took 0.034961 seconds and 6 git commands to generate.