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-/*
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- * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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- * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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- *
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- * This copyrighted material is made available to anyone wishing to use,
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- * modify, copy, or redistribute it subject to the terms and conditions
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- * of the GNU General Public License v.2.
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- */
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-
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-/*
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- * These routines are used by the resource group routines (rgrp.c)
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- * to keep track of block allocation. Each block is represented by two
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- * bits. One bit indicates whether or not the block is used. (1=used,
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- * 0=free) The other bit indicates whether or not the block contains a
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- * dinode or not. (1=dinode, 0=not-dinode) So, each byte represents
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- * GFS2_NBBY (i.e. 4) blocks.
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- */
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-
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-#include <linux/sched.h>
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-#include <linux/slab.h>
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-#include <linux/spinlock.h>
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-#include <linux/completion.h>
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-#include <linux/buffer_head.h>
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-#include <linux/gfs2_ondisk.h>
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-#include <asm/semaphore.h>
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-
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-#include "gfs2.h"
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-#include "lm_interface.h"
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-#include "incore.h"
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-#include "bits.h"
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-#include "util.h"
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-
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-static const char valid_change[16] = {
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- /* current */
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- /* n */ 0, 1, 0, 1,
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- /* e */ 1, 0, 0, 0,
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- /* w */ 0, 0, 0, 0,
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- 1, 0, 0, 0
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-};
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-
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-/**
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- * gfs2_setbit - Set a bit in the bitmaps
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- * @buffer: the buffer that holds the bitmaps
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- * @buflen: the length (in bytes) of the buffer
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- * @block: the block to set
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- * @new_state: the new state of the block
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- *
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- */
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-
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-void gfs2_setbit(struct gfs2_rgrpd *rgd, unsigned char *buffer,
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- unsigned int buflen, uint32_t block, unsigned char new_state)
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-{
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- unsigned char *byte, *end, cur_state;
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- unsigned int bit;
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-
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- byte = buffer + (block / GFS2_NBBY);
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- bit = (block % GFS2_NBBY) * GFS2_BIT_SIZE;
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- end = buffer + buflen;
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-
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- gfs2_assert(rgd->rd_sbd, byte < end);
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-
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- cur_state = (*byte >> bit) & GFS2_BIT_MASK;
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-
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- if (valid_change[new_state * 4 + cur_state]) {
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- *byte ^= cur_state << bit;
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- *byte |= new_state << bit;
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- } else
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- gfs2_consist_rgrpd(rgd);
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-}
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-
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-/**
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- * gfs2_testbit - test a bit in the bitmaps
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- * @buffer: the buffer that holds the bitmaps
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- * @buflen: the length (in bytes) of the buffer
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- * @block: the block to read
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- *
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- */
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-
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-unsigned char gfs2_testbit(struct gfs2_rgrpd *rgd, unsigned char *buffer,
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- unsigned int buflen, uint32_t block)
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-{
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- unsigned char *byte, *end, cur_state;
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- unsigned int bit;
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-
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- byte = buffer + (block / GFS2_NBBY);
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- bit = (block % GFS2_NBBY) * GFS2_BIT_SIZE;
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- end = buffer + buflen;
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-
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- gfs2_assert(rgd->rd_sbd, byte < end);
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-
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- cur_state = (*byte >> bit) & GFS2_BIT_MASK;
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-
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- return cur_state;
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-}
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-
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-/**
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- * gfs2_bitfit - Search an rgrp's bitmap buffer to find a bit-pair representing
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- * a block in a given allocation state.
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- * @buffer: the buffer that holds the bitmaps
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- * @buflen: the length (in bytes) of the buffer
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- * @goal: start search at this block's bit-pair (within @buffer)
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- * @old_state: GFS2_BLKST_XXX the state of the block we're looking for;
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- * bit 0 = alloc(1)/free(0), bit 1 = meta(1)/data(0)
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- *
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- * Scope of @goal and returned block number is only within this bitmap buffer,
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- * not entire rgrp or filesystem. @buffer will be offset from the actual
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- * beginning of a bitmap block buffer, skipping any header structures.
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- *
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- * Return: the block number (bitmap buffer scope) that was found
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- */
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-
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-uint32_t gfs2_bitfit(struct gfs2_rgrpd *rgd, unsigned char *buffer,
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- unsigned int buflen, uint32_t goal,
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- unsigned char old_state)
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-{
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- unsigned char *byte, *end, alloc;
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- uint32_t blk = goal;
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- unsigned int bit;
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-
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- byte = buffer + (goal / GFS2_NBBY);
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- bit = (goal % GFS2_NBBY) * GFS2_BIT_SIZE;
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- end = buffer + buflen;
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- alloc = (old_state & 1) ? 0 : 0x55;
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-
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- while (byte < end) {
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- if ((*byte & 0x55) == alloc) {
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- blk += (8 - bit) >> 1;
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-
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- bit = 0;
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- byte++;
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-
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- continue;
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- }
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-
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- if (((*byte >> bit) & GFS2_BIT_MASK) == old_state)
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- return blk;
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-
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- bit += GFS2_BIT_SIZE;
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- if (bit >= 8) {
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- bit = 0;
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- byte++;
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- }
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-
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- blk++;
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- }
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-
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- return BFITNOENT;
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-}
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-
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-/**
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- * gfs2_bitcount - count the number of bits in a certain state
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- * @buffer: the buffer that holds the bitmaps
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- * @buflen: the length (in bytes) of the buffer
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- * @state: the state of the block we're looking for
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- *
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- * Returns: The number of bits
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- */
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-
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-uint32_t gfs2_bitcount(struct gfs2_rgrpd *rgd, unsigned char *buffer,
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- unsigned int buflen, unsigned char state)
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-{
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- unsigned char *byte = buffer;
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- unsigned char *end = buffer + buflen;
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- unsigned char state1 = state << 2;
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- unsigned char state2 = state << 4;
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- unsigned char state3 = state << 6;
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- uint32_t count = 0;
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-
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- for (; byte < end; byte++) {
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- if (((*byte) & 0x03) == state)
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- count++;
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- if (((*byte) & 0x0C) == state1)
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- count++;
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- if (((*byte) & 0x30) == state2)
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- count++;
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- if (((*byte) & 0xC0) == state3)
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- count++;
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- }
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-
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- return count;
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-}
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-
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