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232 lines
5.3 KiB
232 lines
5.3 KiB
// 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 ([email protected]), 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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