1 /* 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you 5 * can do whatever you want with this stuff. If we meet some day, and you think 6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7 * ---------------------------------------------------------------------------- 8 * 9 * $FreeBSD$ 10 * 11 */ 12 13 #include "opt_geom.h" 14 15 #include <sys/param.h> 16 #include <sys/systm.h> 17 #include <sys/stdint.h> 18 #include <sys/bio.h> 19 #include <sys/conf.h> 20 #include <sys/disk.h> 21 #include <sys/disklabel.h> 22 23 /*- 24 * Disk error is the preface to plaintive error messages 25 * about failing disk transfers. It prints messages of the form 26 * "hp0g: BLABLABLA cmd=read fsbn 12345 of 12344-12347" 27 * blkdone should be -1 if the position of the error is unknown. 28 * The message is printed with printf. 29 */ 30 void 31 disk_err(struct bio *bp, const char *what, int blkdone, int nl) 32 { 33 daddr_t sn; 34 35 if (bp->bio_dev != NULL) 36 printf("%s: %s ", devtoname(bp->bio_dev), what); 37 else if (bp->bio_disk != NULL) 38 printf("%s%d: %s ", 39 bp->bio_disk->d_name, bp->bio_disk->d_unit, what); 40 else 41 printf("disk??: %s ", what); 42 switch(bp->bio_cmd) { 43 case BIO_READ: printf("cmd=read "); break; 44 case BIO_WRITE: printf("cmd=write "); break; 45 case BIO_DELETE: printf("cmd=delete "); break; 46 case BIO_GETATTR: printf("cmd=getattr "); break; 47 case BIO_SETATTR: printf("cmd=setattr "); break; 48 default: printf("cmd=%x ", bp->bio_cmd); break; 49 } 50 sn = bp->bio_blkno; 51 if (bp->bio_bcount <= DEV_BSIZE) { 52 printf("fsbn %jd%s", (intmax_t)sn, nl ? "\n" : ""); 53 return; 54 } 55 if (blkdone >= 0) { 56 sn += blkdone; 57 printf("fsbn %jd of ", (intmax_t)sn); 58 } 59 printf("%jd-%jd", (intmax_t)bp->bio_blkno, 60 (intmax_t)(bp->bio_blkno + (bp->bio_bcount - 1) / DEV_BSIZE)); 61 if (nl) 62 printf("\n"); 63 } 64 65 /* 66 * Seek sort for disks. 67 * 68 * The buf_queue keep two queues, sorted in ascending block order. The first 69 * queue holds those requests which are positioned after the current block 70 * (in the first request); the second, which starts at queue->switch_point, 71 * holds requests which came in after their block number was passed. Thus 72 * we implement a one way scan, retracting after reaching the end of the drive 73 * to the first request on the second queue, at which time it becomes the 74 * first queue. 75 * 76 * A one-way scan is natural because of the way UNIX read-ahead blocks are 77 * allocated. 78 */ 79 80 void 81 bioq_disksort(bioq, bp) 82 struct bio_queue_head *bioq; 83 struct bio *bp; 84 { 85 struct bio *bq; 86 struct bio *bn; 87 struct bio *be; 88 89 if (!atomic_cmpset_int(&bioq->busy, 0, 1)) 90 panic("Recursing in bioq_disksort()"); 91 be = TAILQ_LAST(&bioq->queue, bio_queue); 92 /* 93 * If the queue is empty or we are an 94 * ordered transaction, then it's easy. 95 */ 96 if ((bq = bioq_first(bioq)) == NULL) { 97 bioq_insert_tail(bioq, bp); 98 bioq->busy = 0; 99 return; 100 } else if (bioq->insert_point != NULL) { 101 102 /* 103 * A certain portion of the list is 104 * "locked" to preserve ordering, so 105 * we can only insert after the insert 106 * point. 107 */ 108 bq = bioq->insert_point; 109 } else { 110 111 /* 112 * If we lie before the last removed (currently active) 113 * request, and are not inserting ourselves into the 114 * "locked" portion of the list, then we must add ourselves 115 * to the second request list. 116 */ 117 if (bp->bio_pblkno < bioq->last_pblkno) { 118 119 bq = bioq->switch_point; 120 /* 121 * If we are starting a new secondary list, 122 * then it's easy. 123 */ 124 if (bq == NULL) { 125 bioq->switch_point = bp; 126 bioq_insert_tail(bioq, bp); 127 bioq->busy = 0; 128 return; 129 } 130 /* 131 * If we lie ahead of the current switch point, 132 * insert us before the switch point and move 133 * the switch point. 134 */ 135 if (bp->bio_pblkno < bq->bio_pblkno) { 136 bioq->switch_point = bp; 137 TAILQ_INSERT_BEFORE(bq, bp, bio_queue); 138 bioq->busy = 0; 139 return; 140 } 141 } else { 142 if (bioq->switch_point != NULL) 143 be = TAILQ_PREV(bioq->switch_point, 144 bio_queue, bio_queue); 145 /* 146 * If we lie between last_pblkno and bq, 147 * insert before bq. 148 */ 149 if (bp->bio_pblkno < bq->bio_pblkno) { 150 TAILQ_INSERT_BEFORE(bq, bp, bio_queue); 151 bioq->busy = 0; 152 return; 153 } 154 } 155 } 156 157 /* 158 * Request is at/after our current position in the list. 159 * Optimize for sequential I/O by seeing if we go at the tail. 160 */ 161 if (bp->bio_pblkno > be->bio_pblkno) { 162 TAILQ_INSERT_AFTER(&bioq->queue, be, bp, bio_queue); 163 bioq->busy = 0; 164 return; 165 } 166 167 /* Otherwise, insertion sort */ 168 while ((bn = TAILQ_NEXT(bq, bio_queue)) != NULL) { 169 170 /* 171 * We want to go after the current request if it is the end 172 * of the first request list, or if the next request is a 173 * larger cylinder than our request. 174 */ 175 if (bn == bioq->switch_point 176 || bp->bio_pblkno < bn->bio_pblkno) 177 break; 178 bq = bn; 179 } 180 TAILQ_INSERT_AFTER(&bioq->queue, bq, bp, bio_queue); 181 bioq->busy = 0; 182 } 183 184 185