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