fs/hpfs/buffer.c

   1 /*
   2  *  linux/fs/hpfs/buffer.c
   3  *
   4  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
   5  *
   6  *  general buffer i/o
   7  */
   8 #include <linux/sched.h>
   9 #include <linux/slab.h>
  10 #include "hpfs_fn.h"
  11
  12 /* Map a sector into a buffer and return pointers to it and to the buffer. */
  13
  14 void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
  15                  int ahead)
  16 {
  17         struct buffer_head *bh;
  18
  19         hpfs_lock_assert(s);
  20
  21         cond_resched();
  22
  23         *bhp = bh = sb_bread(s, secno);
  24         if (bh != NULL)
  25                 return bh->b_data;
  26         else {
  27                 printk("HPFS: hpfs_map_sector: read error\n");
  28                 return NULL;
  29         }
  30 }
  31
  32 /* Like hpfs_map_sector but don't read anything */
  33
  34 void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
  35 {
  36         struct buffer_head *bh;
  37         /*return hpfs_map_sector(s, secno, bhp, 0);*/
  38
  39         hpfs_lock_assert(s);
  40
  41         cond_resched();
  42
  43         if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
  44                 if (!buffer_uptodate(bh)) wait_on_buffer(bh);
  45                 set_buffer_uptodate(bh);
  46                 return bh->b_data;
  47         } else {
  48                 printk("HPFS: hpfs_get_sector: getblk failed\n");
  49                 return NULL;
  50         }
  51 }
  52
  53 /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
  54
  55 void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,
  56                    int ahead)
  57 {
  58         struct buffer_head *bh;
  59         char *data;
  60
  61         hpfs_lock_assert(s);
  62
  63         cond_resched();
  64
  65         if (secno & 3) {
  66                 printk("HPFS: hpfs_map_4sectors: unaligned read\n");
  67                 return NULL;
  68         }
  69
  70         qbh->data = data = kmalloc(2048, GFP_NOFS);
  71         if (!data) {
  72                 printk("HPFS: hpfs_map_4sectors: out of memory\n");
  73                 goto bail;
  74         }
  75
  76         qbh->bh[0] = bh = sb_bread(s, secno);
  77         if (!bh)
  78                 goto bail0;
  79         memcpy(data, bh->b_data, 512);
  80
  81         qbh->bh[1] = bh = sb_bread(s, secno + 1);
  82         if (!bh)
  83                 goto bail1;
  84         memcpy(data + 512, bh->b_data, 512);
  85
  86         qbh->bh[2] = bh = sb_bread(s, secno + 2);
  87         if (!bh)
  88                 goto bail2;
  89         memcpy(data + 2 * 512, bh->b_data, 512);
  90
  91         qbh->bh[3] = bh = sb_bread(s, secno + 3);
  92         if (!bh)
  93                 goto bail3;
  94         memcpy(data + 3 * 512, bh->b_data, 512);
  95
  96         return data;
  97
  98  bail3:
  99         brelse(qbh->bh[2]);
 100  bail2:
 101         brelse(qbh->bh[1]);
 102  bail1:
 103         brelse(qbh->bh[0]);
 104  bail0:
 105         kfree(data);
 106         printk("HPFS: hpfs_map_4sectors: read error\n");
 107  bail:
 108         return NULL;
 109 }
 110
 111 /* Don't read sectors */
 112
 113 void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
 114                           struct quad_buffer_head *qbh)
 115 {
 116         cond_resched();
 117
 118         hpfs_lock_assert(s);
 119
 120         if (secno & 3) {
 121                 printk("HPFS: hpfs_get_4sectors: unaligned read\n");
 122                 return NULL;
 123         }
 124
 125         /*return hpfs_map_4sectors(s, secno, qbh, 0);*/
 126         if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
 127                 printk("HPFS: hpfs_get_4sectors: out of memory\n");
 128                 return NULL;
 129         }
 130         if (!(hpfs_get_sector(s, secno, &qbh->bh[0]))) goto bail0;
 131         if (!(hpfs_get_sector(s, secno + 1, &qbh->bh[1]))) goto bail1;
 132         if (!(hpfs_get_sector(s, secno + 2, &qbh->bh[2]))) goto bail2;
 133         if (!(hpfs_get_sector(s, secno + 3, &qbh->bh[3]))) goto bail3;
 134         memcpy(qbh->data, qbh->bh[0]->b_data, 512);
 135         memcpy(qbh->data + 512, qbh->bh[1]->b_data, 512);
 136         memcpy(qbh->data + 2*512, qbh->bh[2]->b_data, 512);
 137         memcpy(qbh->data + 3*512, qbh->bh[3]->b_data, 512);
 138         return qbh->data;
 139
 140         bail3:  brelse(qbh->bh[2]);
 141         bail2:  brelse(qbh->bh[1]);
 142         bail1:  brelse(qbh->bh[0]);
 143         bail0:
 144         return NULL;
 145 }
 146
 147
 148 void hpfs_brelse4(struct quad_buffer_head *qbh)
 149 {
 150         brelse(qbh->bh[3]);
 151         brelse(qbh->bh[2]);
 152         brelse(qbh->bh[1]);
 153         brelse(qbh->bh[0]);
 154         kfree(qbh->data);
 155 }
 156
 157 void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
 158 {
 159         memcpy(qbh->bh[0]->b_data, qbh->data, 512);
 160         memcpy(qbh->bh[1]->b_data, qbh->data + 512, 512);
 161         memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
 162         memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
 163         mark_buffer_dirty(qbh->bh[0]);
 164         mark_buffer_dirty(qbh->bh[1]);
 165         mark_buffer_dirty(qbh->bh[2]);
 166         mark_buffer_dirty(qbh->bh[3]);
 167 }