1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/hpfs/buffer.c 4 * 5 * Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999 6 * 7 * general buffer i/o 8 */ 9 #include <linux/sched.h> 10 #include <linux/slab.h> 11 #include <linux/blkdev.h> 12 #include "hpfs_fn.h" 13 14 secno hpfs_search_hotfix_map(struct super_block *s, secno sec) 15 { 16 unsigned i; 17 struct hpfs_sb_info *sbi = hpfs_sb(s); 18 for (i = 0; unlikely(i < sbi->n_hotfixes); i++) { 19 if (sbi->hotfix_from[i] == sec) { 20 return sbi->hotfix_to[i]; 21 } 22 } 23 return sec; 24 } 25 26 unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n) 27 { 28 unsigned i; 29 struct hpfs_sb_info *sbi = hpfs_sb(s); 30 for (i = 0; unlikely(i < sbi->n_hotfixes); i++) { 31 if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) { 32 n = sbi->hotfix_from[i] - sec; 33 } 34 } 35 return n; 36 } 37 38 void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n) 39 { 40 struct buffer_head *bh; 41 struct blk_plug plug; 42 43 if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size)) 44 return; 45 46 if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n)) 47 return; 48 49 bh = sb_find_get_block(s, secno); 50 if (bh) { 51 if (buffer_uptodate(bh)) { 52 brelse(bh); 53 return; 54 } 55 brelse(bh); 56 } 57 58 blk_start_plug(&plug); 59 while (n > 0) { 60 if (unlikely(secno >= hpfs_sb(s)->sb_fs_size)) 61 break; 62 sb_breadahead(s, secno); 63 secno++; 64 n--; 65 } 66 blk_finish_plug(&plug); 67 } 68 69 /* Map a sector into a buffer and return pointers to it and to the buffer. */ 70 71 void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp, 72 int ahead) 73 { 74 struct buffer_head *bh; 75 76 hpfs_lock_assert(s); 77 78 hpfs_prefetch_sectors(s, secno, ahead); 79 80 cond_resched(); 81 82 *bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno)); 83 if (bh != NULL) 84 return bh->b_data; 85 else { 86 pr_err("%s(): read error\n", __func__); 87 return NULL; 88 } 89 } 90 91 /* Like hpfs_map_sector but don't read anything */ 92 93 void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp) 94 { 95 struct buffer_head *bh; 96 /*return hpfs_map_sector(s, secno, bhp, 0);*/ 97 98 hpfs_lock_assert(s); 99 100 cond_resched(); 101 102 if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) { 103 if (!buffer_uptodate(bh)) wait_on_buffer(bh); 104 set_buffer_uptodate(bh); 105 return bh->b_data; 106 } else { 107 pr_err("%s(): getblk failed\n", __func__); 108 return NULL; 109 } 110 } 111 112 /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */ 113 114 void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh, 115 int ahead) 116 { 117 char *data; 118 119 hpfs_lock_assert(s); 120 121 cond_resched(); 122 123 if (secno & 3) { 124 pr_err("%s(): unaligned read\n", __func__); 125 return NULL; 126 } 127 128 hpfs_prefetch_sectors(s, secno, 4 + ahead); 129 130 if (!hpfs_map_sector(s, secno + 0, &qbh->bh[0], 0)) goto bail0; 131 if (!hpfs_map_sector(s, secno + 1, &qbh->bh[1], 0)) goto bail1; 132 if (!hpfs_map_sector(s, secno + 2, &qbh->bh[2], 0)) goto bail2; 133 if (!hpfs_map_sector(s, secno + 3, &qbh->bh[3], 0)) goto bail3; 134 135 if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) && 136 likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) && 137 likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) { 138 return qbh->data = qbh->bh[0]->b_data; 139 } 140 141 qbh->data = data = kmalloc(2048, GFP_NOFS); 142 if (!data) { 143 pr_err("%s(): out of memory\n", __func__); 144 goto bail4; 145 } 146 147 memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512); 148 memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512); 149 memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512); 150 memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512); 151 152 return data; 153 154 bail4: 155 brelse(qbh->bh[3]); 156 bail3: 157 brelse(qbh->bh[2]); 158 bail2: 159 brelse(qbh->bh[1]); 160 bail1: 161 brelse(qbh->bh[0]); 162 bail0: 163 return NULL; 164 } 165 166 /* Don't read sectors */ 167 168 void *hpfs_get_4sectors(struct super_block *s, unsigned secno, 169 struct quad_buffer_head *qbh) 170 { 171 cond_resched(); 172 173 hpfs_lock_assert(s); 174 175 if (secno & 3) { 176 pr_err("%s(): unaligned read\n", __func__); 177 return NULL; 178 } 179 180 if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0; 181 if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1; 182 if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2; 183 if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3; 184 185 if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) && 186 likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) && 187 likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) { 188 return qbh->data = qbh->bh[0]->b_data; 189 } 190 191 if (!(qbh->data = kmalloc(2048, GFP_NOFS))) { 192 pr_err("%s(): out of memory\n", __func__); 193 goto bail4; 194 } 195 return qbh->data; 196 197 bail4: 198 brelse(qbh->bh[3]); 199 bail3: 200 brelse(qbh->bh[2]); 201 bail2: 202 brelse(qbh->bh[1]); 203 bail1: 204 brelse(qbh->bh[0]); 205 bail0: 206 return NULL; 207 } 208 209 210 void hpfs_brelse4(struct quad_buffer_head *qbh) 211 { 212 if (unlikely(qbh->data != qbh->bh[0]->b_data)) 213 kfree(qbh->data); 214 brelse(qbh->bh[0]); 215 brelse(qbh->bh[1]); 216 brelse(qbh->bh[2]); 217 brelse(qbh->bh[3]); 218 } 219 220 void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh) 221 { 222 if (unlikely(qbh->data != qbh->bh[0]->b_data)) { 223 memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512); 224 memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512); 225 memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512); 226 memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512); 227 } 228 mark_buffer_dirty(qbh->bh[0]); 229 mark_buffer_dirty(qbh->bh[1]); 230 mark_buffer_dirty(qbh->bh[2]); 231 mark_buffer_dirty(qbh->bh[3]); 232 } 233