6833acab2d
Add the BIO_ORDERED flag for struct bio and update bio clients to use it. The barrier semantics of bioq_insert_tail() were broken in two ways: o In bioq_disksort(), an added bio could be inserted at the head of the queue, even when a barrier was present, if the sort key for the new entry was less than that of the last queued barrier bio. o The last_offset used to generate the sort key for newly queued bios did not stay at the position of the barrier until either the barrier was de-queued, or a new barrier (which updates last_offset) was queued. When a barrier is in effect, we know that the disk will pass through the barrier position just before the "blocked bios" are released, so using the barrier's offset for last_offset is the optimal choice. sys/geom/sched/subr_disk.c: sys/kern/subr_disk.c: o Update last_offset in bioq_insert_tail(). o Only update last_offset in bioq_remove() if the removed bio is at the head of the queue (typically due to a call via bioq_takefirst()) and no barrier is active. o In bioq_disksort(), if we have a barrier (insert_point is non-NULL), set prev to the barrier and cur to it's next element. Now that last_offset is kept at the barrier position, this change isn't strictly necessary, but since we have to take a decision branch anyway, it does avoid one, no-op, loop iteration in the while loop that immediately follows. o In bioq_disksort(), bypass the normal sort for bios with the BIO_ORDERED attribute and instead insert them into the queue with bioq_insert_tail(). bioq_insert_tail() not only gives the desired command order during insertion, but also provides barrier semantics so that commands disksorted in the future cannot pass the just enqueued transaction. sys/sys/bio.h: Add BIO_ORDERED as bit 4 of the bio_flags field in struct bio. sys/cam/ata/ata_da.c: sys/cam/scsi/scsi_da.c Use an ordered command for SCSI/ATA-NCQ commands issued in response to bios with the BIO_ORDERED flag set. sys/cam/scsi/scsi_da.c Use an ordered tag when issuing a synchronize cache command. Wrap some lines to 80 columns. sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c sys/geom/geom_io.c Mark bios with the BIO_FLUSH command as BIO_ORDERED. Sponsored by: Spectra Logic Corporation MFC after: 1 month
146 lines
5.3 KiB
C
146 lines
5.3 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)buf.h 8.9 (Berkeley) 3/30/95
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* $FreeBSD$
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*/
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#ifndef _SYS_BIO_H_
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#define _SYS_BIO_H_
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#include <sys/queue.h>
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/* bio_cmd */
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#define BIO_READ 0x01
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#define BIO_WRITE 0x02
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#define BIO_DELETE 0x04
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#define BIO_GETATTR 0x08
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#define BIO_FLUSH 0x10
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#define BIO_CMD0 0x20 /* Available for local hacks */
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#define BIO_CMD1 0x40 /* Available for local hacks */
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#define BIO_CMD2 0x80 /* Available for local hacks */
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/* bio_flags */
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#define BIO_ERROR 0x01
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#define BIO_DONE 0x02
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#define BIO_ONQUEUE 0x04
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#define BIO_ORDERED 0x08
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#ifdef _KERNEL
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struct disk;
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struct bio;
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/* Empty classifier tag, to prevent further classification. */
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#define BIO_NOTCLASSIFIED (void *)(~0UL)
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typedef void bio_task_t(void *);
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/*
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* The bio structure describes an I/O operation in the kernel.
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*/
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struct bio {
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uint8_t bio_cmd; /* I/O operation. */
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uint8_t bio_flags; /* General flags. */
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uint8_t bio_cflags; /* Private use by the consumer. */
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uint8_t bio_pflags; /* Private use by the provider. */
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struct cdev *bio_dev; /* Device to do I/O on. */
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struct disk *bio_disk; /* Valid below geom_disk.c only */
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off_t bio_offset; /* Offset into file. */
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long bio_bcount; /* Valid bytes in buffer. */
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caddr_t bio_data; /* Memory, superblocks, indirect etc. */
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int bio_error; /* Errno for BIO_ERROR. */
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long bio_resid; /* Remaining I/O in bytes. */
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void (*bio_done)(struct bio *);
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void *bio_driver1; /* Private use by the provider. */
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void *bio_driver2; /* Private use by the provider. */
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void *bio_caller1; /* Private use by the consumer. */
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void *bio_caller2; /* Private use by the consumer. */
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TAILQ_ENTRY(bio) bio_queue; /* Disksort queue. */
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const char *bio_attribute; /* Attribute for BIO_[GS]ETATTR */
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struct g_consumer *bio_from; /* GEOM linkage */
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struct g_provider *bio_to; /* GEOM linkage */
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off_t bio_length; /* Like bio_bcount */
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off_t bio_completed; /* Inverse of bio_resid */
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u_int bio_children; /* Number of spawned bios */
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u_int bio_inbed; /* Children safely home by now */
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struct bio *bio_parent; /* Pointer to parent */
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struct bintime bio_t0; /* Time request started */
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bio_task_t *bio_task; /* Task_queue handler */
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void *bio_task_arg; /* Argument to above */
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void *bio_classifier1; /* Classifier tag. */
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void *bio_classifier2; /* Classifier tag. */
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#ifdef DIAGNOSTIC
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void *_bio_caller1;
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void *_bio_caller2;
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uint8_t _bio_cflags;
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#endif
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/* XXX: these go away when bio chaining is introduced */
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daddr_t bio_pblkno; /* physical block number */
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};
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struct uio;
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struct devstat;
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struct bio_queue_head {
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TAILQ_HEAD(bio_queue, bio) queue;
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off_t last_offset;
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struct bio *insert_point;
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};
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void biodone(struct bio *bp);
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void biofinish(struct bio *bp, struct devstat *stat, int error);
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int biowait(struct bio *bp, const char *wchan);
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void bioq_disksort(struct bio_queue_head *ap, struct bio *bp);
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struct bio *bioq_first(struct bio_queue_head *head);
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struct bio *bioq_takefirst(struct bio_queue_head *head);
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void bioq_flush(struct bio_queue_head *head, struct devstat *stp, int error);
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void bioq_init(struct bio_queue_head *head);
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void bioq_insert_head(struct bio_queue_head *head, struct bio *bp);
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void bioq_insert_tail(struct bio_queue_head *head, struct bio *bp);
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void bioq_remove(struct bio_queue_head *head, struct bio *bp);
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void bio_taskqueue(struct bio *bp, bio_task_t *fund, void *arg);
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int physio(struct cdev *dev, struct uio *uio, int ioflag);
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#define physread physio
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#define physwrite physio
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#endif /* _KERNEL */
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#endif /* !_SYS_BIO_H_ */
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