233 lines
5.3 KiB
C
233 lines
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/hpfs/buffer.c
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*
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* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
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*
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* general buffer i/o
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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/blkdev.h>
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#include "hpfs_fn.h"
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secno hpfs_search_hotfix_map(struct super_block *s, secno sec)
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{
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unsigned i;
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
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if (sbi->hotfix_from[i] == sec) {
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return sbi->hotfix_to[i];
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}
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}
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return sec;
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}
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unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n)
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{
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unsigned i;
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
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if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) {
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n = sbi->hotfix_from[i] - sec;
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}
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}
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return n;
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}
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void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
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{
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struct buffer_head *bh;
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struct blk_plug plug;
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if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))
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return;
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if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n))
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return;
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bh = sb_find_get_block(s, secno);
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if (bh) {
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if (buffer_uptodate(bh)) {
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brelse(bh);
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return;
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}
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brelse(bh);
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};
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blk_start_plug(&plug);
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while (n > 0) {
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if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))
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break;
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sb_breadahead(s, secno);
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secno++;
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n--;
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}
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blk_finish_plug(&plug);
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}
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/* Map a sector into a buffer and return pointers to it and to the buffer. */
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void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
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int ahead)
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{
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struct buffer_head *bh;
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hpfs_lock_assert(s);
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hpfs_prefetch_sectors(s, secno, ahead);
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cond_resched();
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*bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno));
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if (bh != NULL)
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return bh->b_data;
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else {
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pr_err("%s(): read error\n", __func__);
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return NULL;
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}
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}
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/* Like hpfs_map_sector but don't read anything */
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void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
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{
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struct buffer_head *bh;
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/*return hpfs_map_sector(s, secno, bhp, 0);*/
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hpfs_lock_assert(s);
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cond_resched();
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if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) {
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if (!buffer_uptodate(bh)) wait_on_buffer(bh);
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set_buffer_uptodate(bh);
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return bh->b_data;
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} else {
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pr_err("%s(): getblk failed\n", __func__);
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return NULL;
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}
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}
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/* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
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void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,
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int ahead)
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{
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char *data;
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hpfs_lock_assert(s);
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cond_resched();
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if (secno & 3) {
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pr_err("%s(): unaligned read\n", __func__);
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return NULL;
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}
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hpfs_prefetch_sectors(s, secno, 4 + ahead);
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if (!hpfs_map_sector(s, secno + 0, &qbh->bh[0], 0)) goto bail0;
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if (!hpfs_map_sector(s, secno + 1, &qbh->bh[1], 0)) goto bail1;
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if (!hpfs_map_sector(s, secno + 2, &qbh->bh[2], 0)) goto bail2;
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if (!hpfs_map_sector(s, secno + 3, &qbh->bh[3], 0)) goto bail3;
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if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
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likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
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likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
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return qbh->data = qbh->bh[0]->b_data;
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}
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qbh->data = data = kmalloc(2048, GFP_NOFS);
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if (!data) {
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pr_err("%s(): out of memory\n", __func__);
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goto bail4;
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}
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memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512);
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memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512);
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memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512);
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memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512);
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return data;
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bail4:
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brelse(qbh->bh[3]);
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bail3:
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brelse(qbh->bh[2]);
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bail2:
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brelse(qbh->bh[1]);
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bail1:
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brelse(qbh->bh[0]);
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bail0:
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return NULL;
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}
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/* Don't read sectors */
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void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
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struct quad_buffer_head *qbh)
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{
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cond_resched();
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hpfs_lock_assert(s);
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if (secno & 3) {
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pr_err("%s(): unaligned read\n", __func__);
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return NULL;
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}
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if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0;
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if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1;
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if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2;
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if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3;
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if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
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likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
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likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
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return qbh->data = qbh->bh[0]->b_data;
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}
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if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
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pr_err("%s(): out of memory\n", __func__);
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goto bail4;
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}
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return qbh->data;
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bail4:
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brelse(qbh->bh[3]);
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bail3:
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brelse(qbh->bh[2]);
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bail2:
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brelse(qbh->bh[1]);
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bail1:
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brelse(qbh->bh[0]);
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bail0:
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return NULL;
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}
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void hpfs_brelse4(struct quad_buffer_head *qbh)
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{
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if (unlikely(qbh->data != qbh->bh[0]->b_data))
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kfree(qbh->data);
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brelse(qbh->bh[0]);
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brelse(qbh->bh[1]);
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brelse(qbh->bh[2]);
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brelse(qbh->bh[3]);
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}
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void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
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{
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if (unlikely(qbh->data != qbh->bh[0]->b_data)) {
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memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512);
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memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512);
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memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
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memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
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}
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mark_buffer_dirty(qbh->bh[0]);
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mark_buffer_dirty(qbh->bh[1]);
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mark_buffer_dirty(qbh->bh[2]);
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mark_buffer_dirty(qbh->bh[3]);
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}
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