linux/fs/ntfs/bitmap.c
Thomas Gleixner a1d312de77 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 96
Based on 1 normalized pattern(s):

  this program include file is free software you can redistribute it
  and or modify it under the terms of the gnu general public license
  as published by the free software foundation either version 2 of the
  license or at your option any later version this program include
  file is distributed in the hope that it will be useful but without
  any warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program in the main directory of the
  linux [ntfs] distribution in the file copying if not write to the
  free software foundation inc 59 temple place suite 330 boston ma
  02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 43 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075212.517001706@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:37:53 +02:00

180 lines
4.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* bitmap.c - NTFS kernel bitmap handling. Part of the Linux-NTFS project.
*
* Copyright (c) 2004-2005 Anton Altaparmakov
*/
#ifdef NTFS_RW
#include <linux/pagemap.h>
#include "bitmap.h"
#include "debug.h"
#include "aops.h"
#include "ntfs.h"
/**
* __ntfs_bitmap_set_bits_in_run - set a run of bits in a bitmap to a value
* @vi: vfs inode describing the bitmap
* @start_bit: first bit to set
* @count: number of bits to set
* @value: value to set the bits to (i.e. 0 or 1)
* @is_rollback: if 'true' this is a rollback operation
*
* Set @count bits starting at bit @start_bit in the bitmap described by the
* vfs inode @vi to @value, where @value is either 0 or 1.
*
* @is_rollback should always be 'false', it is for internal use to rollback
* errors. You probably want to use ntfs_bitmap_set_bits_in_run() instead.
*
* Return 0 on success and -errno on error.
*/
int __ntfs_bitmap_set_bits_in_run(struct inode *vi, const s64 start_bit,
const s64 count, const u8 value, const bool is_rollback)
{
s64 cnt = count;
pgoff_t index, end_index;
struct address_space *mapping;
struct page *page;
u8 *kaddr;
int pos, len;
u8 bit;
BUG_ON(!vi);
ntfs_debug("Entering for i_ino 0x%lx, start_bit 0x%llx, count 0x%llx, "
"value %u.%s", vi->i_ino, (unsigned long long)start_bit,
(unsigned long long)cnt, (unsigned int)value,
is_rollback ? " (rollback)" : "");
BUG_ON(start_bit < 0);
BUG_ON(cnt < 0);
BUG_ON(value > 1);
/*
* Calculate the indices for the pages containing the first and last
* bits, i.e. @start_bit and @start_bit + @cnt - 1, respectively.
*/
index = start_bit >> (3 + PAGE_SHIFT);
end_index = (start_bit + cnt - 1) >> (3 + PAGE_SHIFT);
/* Get the page containing the first bit (@start_bit). */
mapping = vi->i_mapping;
page = ntfs_map_page(mapping, index);
if (IS_ERR(page)) {
if (!is_rollback)
ntfs_error(vi->i_sb, "Failed to map first page (error "
"%li), aborting.", PTR_ERR(page));
return PTR_ERR(page);
}
kaddr = page_address(page);
/* Set @pos to the position of the byte containing @start_bit. */
pos = (start_bit >> 3) & ~PAGE_MASK;
/* Calculate the position of @start_bit in the first byte. */
bit = start_bit & 7;
/* If the first byte is partial, modify the appropriate bits in it. */
if (bit) {
u8 *byte = kaddr + pos;
while ((bit & 7) && cnt) {
cnt--;
if (value)
*byte |= 1 << bit++;
else
*byte &= ~(1 << bit++);
}
/* If we are done, unmap the page and return success. */
if (!cnt)
goto done;
/* Update @pos to the new position. */
pos++;
}
/*
* Depending on @value, modify all remaining whole bytes in the page up
* to @cnt.
*/
len = min_t(s64, cnt >> 3, PAGE_SIZE - pos);
memset(kaddr + pos, value ? 0xff : 0, len);
cnt -= len << 3;
/* Update @len to point to the first not-done byte in the page. */
if (cnt < 8)
len += pos;
/* If we are not in the last page, deal with all subsequent pages. */
while (index < end_index) {
BUG_ON(cnt <= 0);
/* Update @index and get the next page. */
flush_dcache_page(page);
set_page_dirty(page);
ntfs_unmap_page(page);
page = ntfs_map_page(mapping, ++index);
if (IS_ERR(page))
goto rollback;
kaddr = page_address(page);
/*
* Depending on @value, modify all remaining whole bytes in the
* page up to @cnt.
*/
len = min_t(s64, cnt >> 3, PAGE_SIZE);
memset(kaddr, value ? 0xff : 0, len);
cnt -= len << 3;
}
/*
* The currently mapped page is the last one. If the last byte is
* partial, modify the appropriate bits in it. Note, @len is the
* position of the last byte inside the page.
*/
if (cnt) {
u8 *byte;
BUG_ON(cnt > 7);
bit = cnt;
byte = kaddr + len;
while (bit--) {
if (value)
*byte |= 1 << bit;
else
*byte &= ~(1 << bit);
}
}
done:
/* We are done. Unmap the page and return success. */
flush_dcache_page(page);
set_page_dirty(page);
ntfs_unmap_page(page);
ntfs_debug("Done.");
return 0;
rollback:
/*
* Current state:
* - no pages are mapped
* - @count - @cnt is the number of bits that have been modified
*/
if (is_rollback)
return PTR_ERR(page);
if (count != cnt)
pos = __ntfs_bitmap_set_bits_in_run(vi, start_bit, count - cnt,
value ? 0 : 1, true);
else
pos = 0;
if (!pos) {
/* Rollback was successful. */
ntfs_error(vi->i_sb, "Failed to map subsequent page (error "
"%li), aborting.", PTR_ERR(page));
} else {
/* Rollback failed. */
ntfs_error(vi->i_sb, "Failed to map subsequent page (error "
"%li) and rollback failed (error %i). "
"Aborting and leaving inconsistent metadata. "
"Unmount and run chkdsk.", PTR_ERR(page), pos);
NVolSetErrors(NTFS_SB(vi->i_sb));
}
return PTR_ERR(page);
}
#endif /* NTFS_RW */