493 lines
11 KiB
C
493 lines
11 KiB
C
/*
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* blkmap64_ba.c --- Simple bitarray implementation for bitmaps
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*
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* Copyright (C) 2008 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include "config.h"
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#include <stdio.h>
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <fcntl.h>
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#include <time.h>
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#if HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#if HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#include "ext2_fs.h"
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#include "ext2fsP.h"
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#include "bmap64.h"
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/*
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* Private data for bit array implementation of bitmap ops.
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* Currently, this is just a pointer to our big flat hunk of memory,
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* exactly equivalent to the old-skool char * bitmap member.
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*/
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struct ext2fs_ba_private_struct {
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char *bitarray;
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};
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typedef struct ext2fs_ba_private_struct *ext2fs_ba_private;
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static errcode_t ba_alloc_private_data (ext2fs_generic_bitmap_64 bitmap)
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{
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ext2fs_ba_private bp;
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errcode_t retval;
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size_t size;
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/*
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* Since we only have the one pointer, we could just shove our
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* private data in the void *private field itself, but then
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* we'd have to do a fair bit of rewriting if we ever added a
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* field. I'm agnostic.
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*/
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retval = ext2fs_get_mem(sizeof (ext2fs_ba_private), &bp);
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if (retval)
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return retval;
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size = (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1);
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retval = ext2fs_get_mem(size, &bp->bitarray);
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if (retval) {
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ext2fs_free_mem(&bp);
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bp = 0;
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return retval;
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}
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bitmap->private = (void *) bp;
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return 0;
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}
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static errcode_t ba_new_bmap(ext2_filsys fs EXT2FS_ATTR((unused)),
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ext2fs_generic_bitmap_64 bitmap)
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{
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ext2fs_ba_private bp;
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errcode_t retval;
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size_t size;
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retval = ba_alloc_private_data (bitmap);
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if (retval)
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return retval;
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bp = (ext2fs_ba_private) bitmap->private;
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size = (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1);
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memset(bp->bitarray, 0, size);
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return 0;
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}
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static void ba_free_bmap(ext2fs_generic_bitmap_64 bitmap)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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if (!bp)
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return;
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if (bp->bitarray) {
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ext2fs_free_mem (&bp->bitarray);
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bp->bitarray = 0;
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}
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ext2fs_free_mem (&bp);
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bp = 0;
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}
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static errcode_t ba_copy_bmap(ext2fs_generic_bitmap_64 src,
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ext2fs_generic_bitmap_64 dest)
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{
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ext2fs_ba_private src_bp = (ext2fs_ba_private) src->private;
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ext2fs_ba_private dest_bp;
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errcode_t retval;
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size_t size;
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retval = ba_alloc_private_data (dest);
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if (retval)
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return retval;
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dest_bp = (ext2fs_ba_private) dest->private;
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size = (size_t) (((src->real_end - src->start) / 8) + 1);
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memcpy (dest_bp->bitarray, src_bp->bitarray, size);
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return 0;
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}
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static errcode_t ba_resize_bmap(ext2fs_generic_bitmap_64 bmap,
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__u64 new_end, __u64 new_real_end)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bmap->private;
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errcode_t retval;
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size_t size, new_size;
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__u64 bitno;
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/*
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* If we're expanding the bitmap, make sure all of the new
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* parts of the bitmap are zero.
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*/
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if (new_end > bmap->end) {
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bitno = bmap->real_end;
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if (bitno > new_end)
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bitno = new_end;
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for (; bitno > bmap->end; bitno--)
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ext2fs_clear_bit64(bitno - bmap->start, bp->bitarray);
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}
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if (new_real_end == bmap->real_end) {
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bmap->end = new_end;
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return 0;
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}
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size = ((bmap->real_end - bmap->start) / 8) + 1;
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new_size = ((new_real_end - bmap->start) / 8) + 1;
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if (size != new_size) {
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retval = ext2fs_resize_mem(size, new_size, &bp->bitarray);
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if (retval)
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return retval;
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}
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if (new_size > size)
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memset(bp->bitarray + size, 0, new_size - size);
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bmap->end = new_end;
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bmap->real_end = new_real_end;
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return 0;
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}
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static int ba_mark_bmap(ext2fs_generic_bitmap_64 bitmap, __u64 arg)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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blk64_t bitno = (blk64_t) arg;
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return ext2fs_set_bit64(bitno - bitmap->start, bp->bitarray);
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}
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static int ba_unmark_bmap(ext2fs_generic_bitmap_64 bitmap, __u64 arg)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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blk64_t bitno = (blk64_t) arg;
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return ext2fs_clear_bit64(bitno - bitmap->start, bp->bitarray);
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}
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static int ba_test_bmap(ext2fs_generic_bitmap_64 bitmap, __u64 arg)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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blk64_t bitno = (blk64_t) arg;
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return ext2fs_test_bit64(bitno - bitmap->start, bp->bitarray);
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}
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static void ba_mark_bmap_extent(ext2fs_generic_bitmap_64 bitmap, __u64 arg,
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unsigned int num)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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blk64_t bitno = (blk64_t) arg;
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unsigned int i;
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for (i = 0; i < num; i++)
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ext2fs_fast_set_bit64(bitno + i - bitmap->start, bp->bitarray);
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}
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static void ba_unmark_bmap_extent(ext2fs_generic_bitmap_64 bitmap, __u64 arg,
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unsigned int num)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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blk64_t bitno = (blk64_t) arg;
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unsigned int i;
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for (i = 0; i < num; i++)
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ext2fs_fast_clear_bit64(bitno + i - bitmap->start, bp->bitarray);
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}
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static int ba_test_clear_bmap_extent(ext2fs_generic_bitmap_64 bitmap,
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__u64 start, unsigned int len)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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__u64 start_byte, len_byte = len >> 3;
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unsigned int start_bit, len_bit = len % 8;
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unsigned int first_bit = 0;
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unsigned int last_bit = 0;
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int mark_count = 0;
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int mark_bit = 0;
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int i;
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const char *ADDR;
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ADDR = bp->bitarray;
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start -= bitmap->start;
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start_byte = start >> 3;
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start_bit = start % 8;
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if (start_bit != 0) {
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/*
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* The compared start block number or start inode number
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* is not the first bit in a byte.
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*/
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mark_count = 8 - start_bit;
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if (len < 8 - start_bit) {
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mark_count = (int)len;
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mark_bit = len + start_bit - 1;
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} else
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mark_bit = 7;
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for (i = mark_count; i > 0; i--, mark_bit--)
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first_bit |= 1 << mark_bit;
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/*
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* Compare blocks or inodes in the first byte.
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* If there is any marked bit, this function returns 0.
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*/
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if (first_bit & ADDR[start_byte])
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return 0;
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else if (len <= 8 - start_bit)
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return 1;
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start_byte++;
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len_bit = (len - mark_count) % 8;
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len_byte = (len - mark_count) >> 3;
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}
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/*
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* The compared start block number or start inode number is
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* the first bit in a byte.
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*/
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if (len_bit != 0) {
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/*
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* The compared end block number or end inode number is
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* not the last bit in a byte.
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*/
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for (mark_bit = len_bit - 1; mark_bit >= 0; mark_bit--)
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last_bit |= 1 << mark_bit;
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/*
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* Compare blocks or inodes in the last byte.
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* If there is any marked bit, this function returns 0.
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*/
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if (last_bit & ADDR[start_byte + len_byte])
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return 0;
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else if (len_byte == 0)
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return 1;
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}
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/* Check whether all bytes are 0 */
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return ext2fs_mem_is_zero(ADDR + start_byte, len_byte);
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}
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static errcode_t ba_set_bmap_range(ext2fs_generic_bitmap_64 bitmap,
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__u64 start, size_t num, void *in)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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memcpy (bp->bitarray + (start >> 3), in, (num + 7) >> 3);
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return 0;
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}
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static errcode_t ba_get_bmap_range(ext2fs_generic_bitmap_64 bitmap,
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__u64 start, size_t num, void *out)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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memcpy (out, bp->bitarray + (start >> 3), (num + 7) >> 3);
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return 0;
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}
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static void ba_clear_bmap(ext2fs_generic_bitmap_64 bitmap)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private;
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memset(bp->bitarray, 0,
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(size_t) (((bitmap->real_end - bitmap->start) / 8) + 1));
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}
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#ifdef ENABLE_BMAP_STATS
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static void ba_print_stats(ext2fs_generic_bitmap_64 bitmap)
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{
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fprintf(stderr, "%16llu Bytes used by bitarray\n", (unsigned long long)
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((bitmap->real_end - bitmap->start) >> 3) + 1 +
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sizeof(struct ext2fs_ba_private_struct));
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}
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#else
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static void ba_print_stats(ext2fs_generic_bitmap_64 bitmap EXT2FS_ATTR((unused)))
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{
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}
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#endif
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/* Find the first zero bit between start and end, inclusive. */
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static errcode_t ba_find_first_zero(ext2fs_generic_bitmap_64 bitmap,
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__u64 start, __u64 end, __u64 *out)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private)bitmap->private;
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unsigned long bitpos = start - bitmap->start;
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unsigned long count = end - start + 1;
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int byte_found = 0; /* whether a != 0xff byte has been found */
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const unsigned char *pos;
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unsigned long max_loop_count, i;
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/* scan bits until we hit a byte boundary */
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while ((bitpos & 0x7) != 0 && count > 0) {
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if (!ext2fs_test_bit64(bitpos, bp->bitarray)) {
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*out = bitpos + bitmap->start;
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return 0;
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}
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bitpos++;
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count--;
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}
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if (!count)
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return ENOENT;
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pos = ((unsigned char *)bp->bitarray) + (bitpos >> 3);
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/* scan bytes until 8-byte (64-bit) aligned */
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while (count >= 8 && (((uintptr_t)pos) & 0x07)) {
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if (*pos != 0xff) {
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byte_found = 1;
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break;
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}
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pos++;
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count -= 8;
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bitpos += 8;
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}
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if (!byte_found) {
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max_loop_count = count >> 6; /* 8-byte blocks */
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i = max_loop_count;
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while (i) {
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if (*((const __u64 *)pos) != ((__u64)-1))
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break;
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pos += 8;
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i--;
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}
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count -= 64 * (max_loop_count - i);
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bitpos += 64 * (max_loop_count - i);
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max_loop_count = count >> 3;
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i = max_loop_count;
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while (i) {
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if (*pos != 0xff) {
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byte_found = 1;
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break;
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}
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pos++;
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i--;
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}
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count -= 8 * (max_loop_count - i);
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bitpos += 8 * (max_loop_count - i);
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}
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/* Here either count < 8 or byte_found == 1. */
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while (count-- > 0) {
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if (!ext2fs_test_bit64(bitpos, bp->bitarray)) {
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*out = bitpos + bitmap->start;
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return 0;
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}
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bitpos++;
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}
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return ENOENT;
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}
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/* Find the first one bit between start and end, inclusive. */
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static errcode_t ba_find_first_set(ext2fs_generic_bitmap_64 bitmap,
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__u64 start, __u64 end, __u64 *out)
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{
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ext2fs_ba_private bp = (ext2fs_ba_private)bitmap->private;
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unsigned long bitpos = start - bitmap->start;
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unsigned long count = end - start + 1;
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int byte_found = 0; /* whether a != 0xff byte has been found */
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const unsigned char *pos;
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unsigned long max_loop_count, i;
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/* scan bits until we hit a byte boundary */
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while ((bitpos & 0x7) != 0 && count > 0) {
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if (ext2fs_test_bit64(bitpos, bp->bitarray)) {
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*out = bitpos + bitmap->start;
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return 0;
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}
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bitpos++;
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count--;
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}
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if (!count)
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return ENOENT;
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pos = ((unsigned char *)bp->bitarray) + (bitpos >> 3);
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/* scan bytes until 8-byte (64-bit) aligned */
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while (count >= 8 && (((uintptr_t)pos) & 0x07)) {
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if (*pos != 0) {
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byte_found = 1;
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break;
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}
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pos++;
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count -= 8;
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bitpos += 8;
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}
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if (!byte_found) {
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max_loop_count = count >> 6; /* 8-byte blocks */
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i = max_loop_count;
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while (i) {
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if (*((const __u64 *)pos) != 0)
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break;
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pos += 8;
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i--;
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}
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count -= 64 * (max_loop_count - i);
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bitpos += 64 * (max_loop_count - i);
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max_loop_count = count >> 3;
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i = max_loop_count;
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while (i) {
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if (*pos != 0) {
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byte_found = 1;
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break;
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}
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pos++;
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i--;
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}
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count -= 8 * (max_loop_count - i);
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bitpos += 8 * (max_loop_count - i);
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}
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/* Here either count < 8 or byte_found == 1. */
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while (count-- > 0) {
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if (ext2fs_test_bit64(bitpos, bp->bitarray)) {
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*out = bitpos + bitmap->start;
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return 0;
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}
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bitpos++;
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}
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return ENOENT;
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}
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struct ext2_bitmap_ops ext2fs_blkmap64_bitarray = {
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.type = EXT2FS_BMAP64_BITARRAY,
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.new_bmap = ba_new_bmap,
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.free_bmap = ba_free_bmap,
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.copy_bmap = ba_copy_bmap,
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.resize_bmap = ba_resize_bmap,
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.mark_bmap = ba_mark_bmap,
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.unmark_bmap = ba_unmark_bmap,
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.test_bmap = ba_test_bmap,
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.test_clear_bmap_extent = ba_test_clear_bmap_extent,
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.mark_bmap_extent = ba_mark_bmap_extent,
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.unmark_bmap_extent = ba_unmark_bmap_extent,
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.set_bmap_range = ba_set_bmap_range,
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.get_bmap_range = ba_get_bmap_range,
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.clear_bmap = ba_clear_bmap,
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.print_stats = ba_print_stats,
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.find_first_zero = ba_find_first_zero,
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.find_first_set = ba_find_first_set
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};
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