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 * ----------------------------------------------------------------------------
10 #include <sys/cdefs.h>
11 __FBSDID("$FreeBSD$");
15 #include <sys/param.h>
16 #include <sys/systm.h>
20 #include <geom/geom_disk.h>
23 * Disk error is the preface to plaintive error messages
24 * about failing disk transfers. It prints messages of the form
25 * "hp0g: BLABLABLA cmd=read fsbn 12345 of 12344-12347"
26 * blkdone should be -1 if the position of the error is unknown.
27 * The message is printed with printf.
30 disk_err(struct bio *bp, const char *what, int blkdone, int nl)
34 if (bp->bio_dev != NULL)
35 printf("%s: %s ", devtoname(bp->bio_dev), what);
36 else if (bp->bio_disk != NULL)
38 bp->bio_disk->d_name, bp->bio_disk->d_unit, what);
40 printf("disk??: %s ", what);
42 case BIO_READ: printf("cmd=read "); break;
43 case BIO_WRITE: printf("cmd=write "); break;
44 case BIO_DELETE: printf("cmd=delete "); break;
45 case BIO_GETATTR: printf("cmd=getattr "); break;
46 default: printf("cmd=%x ", bp->bio_cmd); break;
49 if (bp->bio_bcount <= DEV_BSIZE) {
50 printf("fsbn %jd%s", (intmax_t)sn, nl ? "\n" : "");
55 printf("fsbn %jd of ", (intmax_t)sn);
57 printf("%jd-%jd", (intmax_t)bp->bio_pblkno,
58 (intmax_t)(bp->bio_pblkno + (bp->bio_bcount - 1) / DEV_BSIZE));
64 * BIO queue implementation
68 bioq_init(struct bio_queue_head *head)
70 TAILQ_INIT(&head->queue);
71 head->last_offset = 0;
72 head->insert_point = NULL;
76 bioq_remove(struct bio_queue_head *head, struct bio *bp)
78 if (bp == head->insert_point) {
79 head->last_offset = bp->bio_offset;
80 head->insert_point = TAILQ_NEXT(bp, bio_queue);
81 if (head->insert_point == NULL) {
82 head->last_offset = 0;
83 head->insert_point = TAILQ_FIRST(&head->queue);
86 TAILQ_REMOVE(&head->queue, bp, bio_queue);
90 bioq_flush(struct bio_queue_head *head, struct devstat *stp, int error)
94 while ((bp = bioq_takefirst(head)) != NULL)
95 biofinish(bp, stp, error);
99 bioq_insert_head(struct bio_queue_head *head, struct bio *bp)
102 if (TAILQ_FIRST(&head->queue) == NULL)
103 head->insert_point = bp;
104 TAILQ_INSERT_HEAD(&head->queue, bp, bio_queue);
108 bioq_insert_tail(struct bio_queue_head *head, struct bio *bp)
111 if (TAILQ_FIRST(&head->queue) == NULL)
112 head->insert_point = bp;
113 TAILQ_INSERT_TAIL(&head->queue, bp, bio_queue);
117 bioq_first(struct bio_queue_head *head)
120 return (TAILQ_FIRST(&head->queue));
124 bioq_takefirst(struct bio_queue_head *head)
128 bp = TAILQ_FIRST(&head->queue);
130 bioq_remove(head, bp);
135 * Seek sort for disks.
137 * The disksort algorithm sorts all requests in a single queue while keeping
138 * track of the current position of the disk with insert_point and
139 * last_offset. last_offset is the offset of the last block sent to disk, or
140 * 0 once we reach the end. insert_point points to the first buf after
141 * last_offset, and is used to slightly speed up insertions. Blocks are
142 * always sorted in ascending order and the queue always restarts at 0.
143 * This implements the one-way scan which optimizes disk seek times.
146 bioq_disksort(bioq, bp)
147 struct bio_queue_head *bioq;
154 * If the queue is empty then it's easy.
156 if ((bq = bioq_first(bioq)) == NULL) {
157 bioq_insert_tail(bioq, bp);
161 * Optimize for sequential I/O by seeing if we go at the tail.
163 bq = TAILQ_LAST(&bioq->queue, bio_queue);
164 if (bp->bio_offset > bq->bio_offset) {
165 TAILQ_INSERT_AFTER(&bioq->queue, bq, bp, bio_queue);
169 * Pick our scan start based on the last request. A poor man's
172 if (bp->bio_offset >= bioq->last_offset) {
173 bq = bioq->insert_point;
175 * If we're before the next bio and after the last offset,
176 * update insert_point;
178 if (bp->bio_offset < bq->bio_offset) {
179 bioq->insert_point = bp;
180 TAILQ_INSERT_BEFORE(bq, bp, bio_queue);
184 bq = TAILQ_FIRST(&bioq->queue);
185 if (bp->bio_offset < bq->bio_offset) {
186 TAILQ_INSERT_BEFORE(bq, bp, bio_queue);
190 while ((bn = TAILQ_NEXT(bq, bio_queue)) != NULL) {
191 if (bp->bio_offset < bn->bio_offset)
195 TAILQ_INSERT_AFTER(&bioq->queue, bq, bp, bio_queue);