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698b1a6643
BO_LOCK/UNLOCK/MTX when manipulating the bufobj. - Create a new lock in the bufobj to lock bufobj fields independently. This leaves the vnode interlock as an 'identity' lock while the bufobj is an io lock. The bufobj lock is ordered before the vnode interlock and also before the mnt ilock. - Exploit this new lock order to simplify softdep_check_suspend(). - A few sync related functions are marked with a new XXX to note that we may not properly interlock against a non-zero bv_cnt when attempting to sync all vnodes on a mountlist. I do not believe this race is important. If I'm wrong this will make these locations easier to find. Reviewed by: kib (earlier diff) Tested by: kris, pho (earlier diff)
133 lines
4.7 KiB
C
133 lines
4.7 KiB
C
/*-
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* Copyright (c) 2004 Poul-Henning Kamp
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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* $FreeBSD$
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*/
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/*
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* Architectural notes:
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*
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* bufobj is a new object which is what buffers hang from in the buffer
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* cache.
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*
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* This used to be vnodes, but we need non-vnode code to be able
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* to use the buffer cache as well, specifically geom classes like gbde,
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* raid3 and raid5.
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*
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* All vnodes will contain a bufobj initially, but down the road we may
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* want to only allocate bufobjs when they are needed. There could be a
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* large number of vnodes in the system which wouldn't need a bufobj during
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* their lifetime.
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*
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* The exact relationship to the vmobject is not determined at this point,
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* it may in fact be that we find them to be two sides of the same object
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* once things starts to crystalize.
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*/
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#ifndef _SYS_BUFOBJ_H_
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#define _SYS_BUFOBJ_H_
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#if defined(_KERNEL) || defined(_KVM_VNODE)
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#include <sys/queue.h>
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#include <sys/_lock.h>
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#include <sys/_mutex.h>
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struct bufobj;
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struct buf_ops;
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struct thread;
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extern struct buf_ops buf_ops_bio;
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TAILQ_HEAD(buflists, buf);
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/* A Buffer splay list */
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struct bufv {
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struct buflists bv_hd; /* Sorted blocklist */
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struct buf *bv_root; /* Buf splay tree */
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int bv_cnt; /* Number of buffers */
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};
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typedef void b_strategy_t(struct bufobj *, struct buf *);
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typedef int b_write_t(struct buf *);
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typedef int b_sync_t(struct bufobj *, int waitfor, struct thread *td);
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typedef void b_bdflush_t(struct bufobj *, struct buf *);
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struct buf_ops {
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char *bop_name;
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b_write_t *bop_write;
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b_strategy_t *bop_strategy;
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b_sync_t *bop_sync;
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b_bdflush_t *bop_bdflush;
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};
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#define BO_STRATEGY(bo, bp) ((bo)->bo_ops->bop_strategy((bo), (bp)))
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#define BO_SYNC(bo, w, td) ((bo)->bo_ops->bop_sync((bo), (w), (td)))
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#define BO_WRITE(bo, bp) ((bo)->bo_ops->bop_write((bp)))
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#define BO_BDFLUSH(bo, bp) ((bo)->bo_ops->bop_bdflush((bo), (bp)))
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struct bufobj {
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struct mtx bo_mtx; /* Mutex which protects "i" things */
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struct bufv bo_clean; /* i Clean buffers */
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struct bufv bo_dirty; /* i Dirty buffers */
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long bo_numoutput; /* i Writes in progress */
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u_int bo_flag; /* i Flags */
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struct buf_ops *bo_ops; /* - Buffer operations */
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int bo_bsize; /* - Block size for i/o */
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struct vm_object *bo_object; /* v Place to store VM object */
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LIST_ENTRY(bufobj) bo_synclist; /* S dirty vnode list */
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void *bo_private; /* private pointer */
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struct vnode *__bo_vnode; /*
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* XXX: This vnode pointer is here
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* XXX: only to keep the syncer working
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* XXX: for now.
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*/
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};
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/*
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* XXX BO_ONWORKLST could be replaced with a check for NULL list elements
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* in v_synclist.
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*/
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#define BO_ONWORKLST (1 << 0) /* On syncer work-list */
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#define BO_WWAIT (1 << 1) /* Wait for output to complete */
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#define BO_NEEDSGIANT (1 << 2) /* Require giant for child buffers. */
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#define BO_MTX(bo) (&(bo)->bo_mtx)
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#define BO_LOCK(bo) mtx_lock(BO_MTX((bo)))
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#define BO_UNLOCK(bo) mtx_unlock(BO_MTX((bo)))
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#define ASSERT_BO_LOCKED(bo) mtx_assert(BO_MTX((bo)), MA_OWNED)
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#define ASSERT_BO_UNLOCKED(bo) mtx_assert(BO_MTX((bo)), MA_NOTOWNED)
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void bufobj_wdrop(struct bufobj *bo);
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void bufobj_wref(struct bufobj *bo);
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void bufobj_wrefl(struct bufobj *bo);
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int bufobj_invalbuf(struct bufobj *bo, int flags, struct thread *td, int slpflag, int slptimeo);
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int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
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int bufsync(struct bufobj *bo, int waitfor, struct thread *td);
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void bufbdflush(struct bufobj *bo, struct buf *bp);
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#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
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#endif /* _SYS_BUFOBJ_H_ */
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