diff options
Diffstat (limited to 'sys/kern/subr_disk.c')
| -rw-r--r-- | sys/kern/subr_disk.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c new file mode 100644 index 0000000..47ed36e --- /dev/null +++ b/sys/kern/subr_disk.c @@ -0,0 +1,232 @@ +/* + * ---------------------------------------------------------------------------- + * "THE BEER-WARE LICENSE" (Revision 42): + * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you + * can do whatever you want with this stuff. If we meet some day, and you think + * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp + * ---------------------------------------------------------------------------- + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "opt_geom.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/bio.h> +#include <sys/conf.h> +#include <sys/disk.h> +#include <geom/geom_disk.h> + +/*- + * Disk error is the preface to plaintive error messages + * about failing disk transfers. It prints messages of the form + * "hp0g: BLABLABLA cmd=read fsbn 12345 of 12344-12347" + * blkdone should be -1 if the position of the error is unknown. + * The message is printed with printf. + */ +void +disk_err(struct bio *bp, const char *what, int blkdone, int nl) +{ + daddr_t sn; + + if (bp->bio_dev != NULL) + printf("%s: %s ", devtoname(bp->bio_dev), what); + else if (bp->bio_disk != NULL) + printf("%s%d: %s ", + bp->bio_disk->d_name, bp->bio_disk->d_unit, what); + else + printf("disk??: %s ", what); + switch(bp->bio_cmd) { + case BIO_READ: printf("cmd=read "); break; + case BIO_WRITE: printf("cmd=write "); break; + case BIO_DELETE: printf("cmd=delete "); break; + case BIO_GETATTR: printf("cmd=getattr "); break; + default: printf("cmd=%x ", bp->bio_cmd); break; + } + sn = bp->bio_blkno; + if (bp->bio_bcount <= DEV_BSIZE) { + printf("fsbn %jd%s", (intmax_t)sn, nl ? "\n" : ""); + return; + } + if (blkdone >= 0) { + sn += blkdone; + printf("fsbn %jd of ", (intmax_t)sn); + } + printf("%jd-%jd", (intmax_t)bp->bio_blkno, + (intmax_t)(bp->bio_blkno + (bp->bio_bcount - 1) / DEV_BSIZE)); + if (nl) + printf("\n"); +} + +/* + * BIO queue implementation + */ + +void +bioq_init(struct bio_queue_head *head) +{ + TAILQ_INIT(&head->queue); + head->last_pblkno = 0; + head->insert_point = NULL; + head->switch_point = NULL; +} + +void +bioq_remove(struct bio_queue_head *head, struct bio *bp) +{ + if (bp == head->switch_point) + head->switch_point = TAILQ_NEXT(bp, bio_queue); + if (bp == head->insert_point) { + head->insert_point = TAILQ_PREV(bp, bio_queue, bio_queue); + if (head->insert_point == NULL) + head->last_pblkno = 0; + } else if (bp == TAILQ_FIRST(&head->queue)) + head->last_pblkno = bp->bio_pblkno; + TAILQ_REMOVE(&head->queue, bp, bio_queue); + if (TAILQ_FIRST(&head->queue) == head->switch_point) + head->switch_point = NULL; +} + +void +bioq_flush(struct bio_queue_head *head, struct devstat *stp, int error) +{ + struct bio *bp; + + for (;;) { + bp = bioq_first(head); + if (bp == NULL) + break; + bioq_remove(head, bp); + biofinish(bp, stp, ENXIO); + } +} + +void +bioq_insert_tail(struct bio_queue_head *head, struct bio *bp) +{ + + TAILQ_INSERT_TAIL(&head->queue, bp, bio_queue); +} + +struct bio * +bioq_first(struct bio_queue_head *head) +{ + + return (TAILQ_FIRST(&head->queue)); +} + + +/* + * Seek sort for disks. + * + * The buf_queue keep two queues, sorted in ascending block order. The first + * queue holds those requests which are positioned after the current block + * (in the first request); the second, which starts at queue->switch_point, + * holds requests which came in after their block number was passed. Thus + * we implement a one way scan, retracting after reaching the end of the drive + * to the first request on the second queue, at which time it becomes the + * first queue. + * + * A one-way scan is natural because of the way UNIX read-ahead blocks are + * allocated. + */ + +void +bioq_disksort(bioq, bp) + struct bio_queue_head *bioq; + struct bio *bp; +{ + struct bio *bq; + struct bio *bn; + struct bio *be; + + be = TAILQ_LAST(&bioq->queue, bio_queue); + /* + * If the queue is empty or we are an + * ordered transaction, then it's easy. + */ + if ((bq = bioq_first(bioq)) == NULL) { + bioq_insert_tail(bioq, bp); + return; + } else if (bioq->insert_point != NULL) { + + /* + * A certain portion of the list is + * "locked" to preserve ordering, so + * we can only insert after the insert + * point. + */ + bq = bioq->insert_point; + } else { + + /* + * If we lie before the last removed (currently active) + * request, and are not inserting ourselves into the + * "locked" portion of the list, then we must add ourselves + * to the second request list. + */ + if (bp->bio_pblkno < bioq->last_pblkno) { + + bq = bioq->switch_point; + /* + * If we are starting a new secondary list, + * then it's easy. + */ + if (bq == NULL) { + bioq->switch_point = bp; + bioq_insert_tail(bioq, bp); + return; + } + /* + * If we lie ahead of the current switch point, + * insert us before the switch point and move + * the switch point. + */ + if (bp->bio_pblkno < bq->bio_pblkno) { + bioq->switch_point = bp; + TAILQ_INSERT_BEFORE(bq, bp, bio_queue); + return; + } + } else { + if (bioq->switch_point != NULL) + be = TAILQ_PREV(bioq->switch_point, + bio_queue, bio_queue); + /* + * If we lie between last_pblkno and bq, + * insert before bq. + */ + if (bp->bio_pblkno < bq->bio_pblkno) { + TAILQ_INSERT_BEFORE(bq, bp, bio_queue); + return; + } + } + } + + /* + * Request is at/after our current position in the list. + * Optimize for sequential I/O by seeing if we go at the tail. + */ + if (bp->bio_pblkno > be->bio_pblkno) { + TAILQ_INSERT_AFTER(&bioq->queue, be, bp, bio_queue); + return; + } + + /* Otherwise, insertion sort */ + while ((bn = TAILQ_NEXT(bq, bio_queue)) != NULL) { + + /* + * We want to go after the current request if it is the end + * of the first request list, or if the next request is a + * larger cylinder than our request. + */ + if (bn == bioq->switch_point + || bp->bio_pblkno < bn->bio_pblkno) + break; + bq = bn; + } + TAILQ_INSERT_AFTER(&bioq->queue, bq, bp, bio_queue); +} + + |
