4747 lines
122 KiB
C
4747 lines
122 KiB
C
/*-
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* Copyright (c) 2004 Poul-Henning Kamp
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* Copyright (c) 1994,1997 John S. Dyson
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* Copyright (c) 2013 The FreeBSD Foundation
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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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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/*
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* this file contains a new buffer I/O scheme implementing a coherent
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* VM object and buffer cache scheme. Pains have been taken to make
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* sure that the performance degradation associated with schemes such
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* as this is not realized.
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*
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* Author: John S. Dyson
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* Significant help during the development and debugging phases
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* had been provided by David Greenman, also of the FreeBSD core team.
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*
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* see man buf(9) for more info.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bio.h>
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#include <sys/conf.h>
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#include <sys/buf.h>
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#include <sys/devicestat.h>
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#include <sys/eventhandler.h>
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#include <sys/fail.h>
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#include <sys/limits.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/mutex.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/proc.h>
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#include <sys/racct.h>
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#include <sys/resourcevar.h>
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#include <sys/rwlock.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <sys/sysproto.h>
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#include <sys/vmem.h>
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#include <sys/vmmeter.h>
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#include <sys/vnode.h>
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#include <sys/watchdog.h>
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#include <geom/geom.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_page.h>
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#include <vm/vm_object.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_map.h>
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#include <vm/swap_pager.h>
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#include "opt_compat.h"
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#include "opt_swap.h"
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static MALLOC_DEFINE(M_BIOBUF, "biobuf", "BIO buffer");
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struct bio_ops bioops; /* I/O operation notification */
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struct buf_ops buf_ops_bio = {
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.bop_name = "buf_ops_bio",
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.bop_write = bufwrite,
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.bop_strategy = bufstrategy,
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.bop_sync = bufsync,
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.bop_bdflush = bufbdflush,
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};
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static struct buf *buf; /* buffer header pool */
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extern struct buf *swbuf; /* Swap buffer header pool. */
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caddr_t unmapped_buf;
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/* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */
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struct proc *bufdaemonproc;
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struct proc *bufspacedaemonproc;
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static int inmem(struct vnode *vp, daddr_t blkno);
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static void vm_hold_free_pages(struct buf *bp, int newbsize);
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static void vm_hold_load_pages(struct buf *bp, vm_offset_t from,
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vm_offset_t to);
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static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m);
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static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off,
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vm_page_t m);
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static void vfs_clean_pages_dirty_buf(struct buf *bp);
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static void vfs_setdirty_locked_object(struct buf *bp);
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static void vfs_vmio_invalidate(struct buf *bp);
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static void vfs_vmio_truncate(struct buf *bp, int npages);
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static void vfs_vmio_extend(struct buf *bp, int npages, int size);
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static int vfs_bio_clcheck(struct vnode *vp, int size,
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daddr_t lblkno, daddr_t blkno);
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static int buf_flush(struct vnode *vp, int);
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static int buf_recycle(bool);
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static int buf_scan(bool);
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static int flushbufqueues(struct vnode *, int, int);
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static void buf_daemon(void);
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static void bremfreel(struct buf *bp);
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static __inline void bd_wakeup(void);
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static int sysctl_runningspace(SYSCTL_HANDLER_ARGS);
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static void bufkva_reclaim(vmem_t *, int);
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static void bufkva_free(struct buf *);
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static int buf_import(void *, void **, int, int);
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static void buf_release(void *, void **, int);
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#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
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defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
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static int sysctl_bufspace(SYSCTL_HANDLER_ARGS);
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#endif
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int vmiodirenable = TRUE;
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SYSCTL_INT(_vfs, OID_AUTO, vmiodirenable, CTLFLAG_RW, &vmiodirenable, 0,
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"Use the VM system for directory writes");
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long runningbufspace;
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SYSCTL_LONG(_vfs, OID_AUTO, runningbufspace, CTLFLAG_RD, &runningbufspace, 0,
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"Amount of presently outstanding async buffer io");
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static long bufspace;
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#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
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defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
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SYSCTL_PROC(_vfs, OID_AUTO, bufspace, CTLTYPE_LONG|CTLFLAG_MPSAFE|CTLFLAG_RD,
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&bufspace, 0, sysctl_bufspace, "L", "Virtual memory used for buffers");
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#else
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SYSCTL_LONG(_vfs, OID_AUTO, bufspace, CTLFLAG_RD, &bufspace, 0,
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"Physical memory used for buffers");
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#endif
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static long bufkvaspace;
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SYSCTL_LONG(_vfs, OID_AUTO, bufkvaspace, CTLFLAG_RD, &bufkvaspace, 0,
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"Kernel virtual memory used for buffers");
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static long maxbufspace;
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SYSCTL_LONG(_vfs, OID_AUTO, maxbufspace, CTLFLAG_RW, &maxbufspace, 0,
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"Maximum allowed value of bufspace (including metadata)");
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static long bufmallocspace;
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SYSCTL_LONG(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0,
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"Amount of malloced memory for buffers");
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static long maxbufmallocspace;
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SYSCTL_LONG(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace,
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0, "Maximum amount of malloced memory for buffers");
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static long lobufspace;
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SYSCTL_LONG(_vfs, OID_AUTO, lobufspace, CTLFLAG_RW, &lobufspace, 0,
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"Minimum amount of buffers we want to have");
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long hibufspace;
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SYSCTL_LONG(_vfs, OID_AUTO, hibufspace, CTLFLAG_RW, &hibufspace, 0,
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"Maximum allowed value of bufspace (excluding metadata)");
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long bufspacethresh;
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SYSCTL_LONG(_vfs, OID_AUTO, bufspacethresh, CTLFLAG_RW, &bufspacethresh,
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0, "Bufspace consumed before waking the daemon to free some");
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static int buffreekvacnt;
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SYSCTL_INT(_vfs, OID_AUTO, buffreekvacnt, CTLFLAG_RW, &buffreekvacnt, 0,
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"Number of times we have freed the KVA space from some buffer");
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static int bufdefragcnt;
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SYSCTL_INT(_vfs, OID_AUTO, bufdefragcnt, CTLFLAG_RW, &bufdefragcnt, 0,
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"Number of times we have had to repeat buffer allocation to defragment");
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static long lorunningspace;
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SYSCTL_PROC(_vfs, OID_AUTO, lorunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE |
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CTLFLAG_RW, &lorunningspace, 0, sysctl_runningspace, "L",
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"Minimum preferred space used for in-progress I/O");
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static long hirunningspace;
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SYSCTL_PROC(_vfs, OID_AUTO, hirunningspace, CTLTYPE_LONG | CTLFLAG_MPSAFE |
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CTLFLAG_RW, &hirunningspace, 0, sysctl_runningspace, "L",
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"Maximum amount of space to use for in-progress I/O");
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int dirtybufferflushes;
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SYSCTL_INT(_vfs, OID_AUTO, dirtybufferflushes, CTLFLAG_RW, &dirtybufferflushes,
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0, "Number of bdwrite to bawrite conversions to limit dirty buffers");
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int bdwriteskip;
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SYSCTL_INT(_vfs, OID_AUTO, bdwriteskip, CTLFLAG_RW, &bdwriteskip,
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0, "Number of buffers supplied to bdwrite with snapshot deadlock risk");
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int altbufferflushes;
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SYSCTL_INT(_vfs, OID_AUTO, altbufferflushes, CTLFLAG_RW, &altbufferflushes,
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0, "Number of fsync flushes to limit dirty buffers");
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static int recursiveflushes;
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SYSCTL_INT(_vfs, OID_AUTO, recursiveflushes, CTLFLAG_RW, &recursiveflushes,
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0, "Number of flushes skipped due to being recursive");
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static int numdirtybuffers;
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SYSCTL_INT(_vfs, OID_AUTO, numdirtybuffers, CTLFLAG_RD, &numdirtybuffers, 0,
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"Number of buffers that are dirty (has unwritten changes) at the moment");
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static int lodirtybuffers;
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SYSCTL_INT(_vfs, OID_AUTO, lodirtybuffers, CTLFLAG_RW, &lodirtybuffers, 0,
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"How many buffers we want to have free before bufdaemon can sleep");
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static int hidirtybuffers;
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SYSCTL_INT(_vfs, OID_AUTO, hidirtybuffers, CTLFLAG_RW, &hidirtybuffers, 0,
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"When the number of dirty buffers is considered severe");
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int dirtybufthresh;
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SYSCTL_INT(_vfs, OID_AUTO, dirtybufthresh, CTLFLAG_RW, &dirtybufthresh,
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0, "Number of bdwrite to bawrite conversions to clear dirty buffers");
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static int numfreebuffers;
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SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0,
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"Number of free buffers");
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static int lofreebuffers;
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SYSCTL_INT(_vfs, OID_AUTO, lofreebuffers, CTLFLAG_RW, &lofreebuffers, 0,
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"Target number of free buffers");
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static int hifreebuffers;
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SYSCTL_INT(_vfs, OID_AUTO, hifreebuffers, CTLFLAG_RW, &hifreebuffers, 0,
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"Threshold for clean buffer recycling");
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static int getnewbufcalls;
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SYSCTL_INT(_vfs, OID_AUTO, getnewbufcalls, CTLFLAG_RW, &getnewbufcalls, 0,
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"Number of calls to getnewbuf");
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static int getnewbufrestarts;
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SYSCTL_INT(_vfs, OID_AUTO, getnewbufrestarts, CTLFLAG_RW, &getnewbufrestarts, 0,
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"Number of times getnewbuf has had to restart a buffer acquisition");
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static int mappingrestarts;
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SYSCTL_INT(_vfs, OID_AUTO, mappingrestarts, CTLFLAG_RW, &mappingrestarts, 0,
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"Number of times getblk has had to restart a buffer mapping for "
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"unmapped buffer");
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static int numbufallocfails;
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SYSCTL_INT(_vfs, OID_AUTO, numbufallocfails, CTLFLAG_RW, &numbufallocfails, 0,
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"Number of times buffer allocations failed");
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static int flushbufqtarget = 100;
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SYSCTL_INT(_vfs, OID_AUTO, flushbufqtarget, CTLFLAG_RW, &flushbufqtarget, 0,
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"Amount of work to do in flushbufqueues when helping bufdaemon");
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static long notbufdflushes;
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SYSCTL_LONG(_vfs, OID_AUTO, notbufdflushes, CTLFLAG_RD, ¬bufdflushes, 0,
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"Number of dirty buffer flushes done by the bufdaemon helpers");
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static long barrierwrites;
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SYSCTL_LONG(_vfs, OID_AUTO, barrierwrites, CTLFLAG_RW, &barrierwrites, 0,
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"Number of barrier writes");
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SYSCTL_INT(_vfs, OID_AUTO, unmapped_buf_allowed, CTLFLAG_RD,
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&unmapped_buf_allowed, 0,
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"Permit the use of the unmapped i/o");
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/*
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* This lock synchronizes access to bd_request.
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*/
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static struct mtx_padalign bdlock;
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/*
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* This lock protects the runningbufreq and synchronizes runningbufwakeup and
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* waitrunningbufspace().
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*/
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static struct mtx_padalign rbreqlock;
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/*
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* Lock that protects needsbuffer and the sleeps/wakeups surrounding it.
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*/
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static struct rwlock_padalign nblock;
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/*
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* Lock that protects bdirtywait.
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*/
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static struct mtx_padalign bdirtylock;
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/*
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* Wakeup point for bufdaemon, as well as indicator of whether it is already
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* active. Set to 1 when the bufdaemon is already "on" the queue, 0 when it
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* is idling.
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*/
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static int bd_request;
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/*
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* Request/wakeup point for the bufspace daemon.
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*/
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static int bufspace_request;
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/*
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* Request for the buf daemon to write more buffers than is indicated by
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* lodirtybuf. This may be necessary to push out excess dependencies or
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* defragment the address space where a simple count of the number of dirty
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* buffers is insufficient to characterize the demand for flushing them.
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*/
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static int bd_speedupreq;
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/*
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* bogus page -- for I/O to/from partially complete buffers
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* this is a temporary solution to the problem, but it is not
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* really that bad. it would be better to split the buffer
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* for input in the case of buffers partially already in memory,
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* but the code is intricate enough already.
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*/
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vm_page_t bogus_page;
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/*
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* Synchronization (sleep/wakeup) variable for active buffer space requests.
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* Set when wait starts, cleared prior to wakeup().
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* Used in runningbufwakeup() and waitrunningbufspace().
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*/
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static int runningbufreq;
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/*
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* Synchronization (sleep/wakeup) variable for buffer requests.
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* Can contain the VFS_BIO_NEED flags defined below; setting/clearing is done
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* by and/or.
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* Used in numdirtywakeup(), bufspace_wakeup(), bwillwrite(),
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* getnewbuf(), and getblk().
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*/
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static volatile int needsbuffer;
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/*
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* Synchronization for bwillwrite() waiters.
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*/
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static int bdirtywait;
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/*
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* Definitions for the buffer free lists.
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*/
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#define QUEUE_NONE 0 /* on no queue */
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#define QUEUE_EMPTY 1 /* empty buffer headers */
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#define QUEUE_DIRTY 2 /* B_DELWRI buffers */
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#define QUEUE_CLEAN 3 /* non-B_DELWRI buffers */
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#define QUEUE_SENTINEL 1024 /* not an queue index, but mark for sentinel */
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/* Maximum number of clean buffer queues. */
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#define CLEAN_QUEUES 16
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/* Configured number of clean queues. */
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static int clean_queues;
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/* Maximum number of buffer queues. */
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#define BUFFER_QUEUES (QUEUE_CLEAN + CLEAN_QUEUES)
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/* Queues for free buffers with various properties */
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static TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES] = { { 0 } };
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#ifdef INVARIANTS
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static int bq_len[BUFFER_QUEUES];
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#endif
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/*
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* Lock for each bufqueue
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*/
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static struct mtx_padalign bqlocks[BUFFER_QUEUES];
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/*
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* per-cpu empty buffer cache.
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*/
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uma_zone_t buf_zone;
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/*
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* Single global constant for BUF_WMESG, to avoid getting multiple references.
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* buf_wmesg is referred from macros.
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*/
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const char *buf_wmesg = BUF_WMESG;
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static int
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sysctl_runningspace(SYSCTL_HANDLER_ARGS)
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{
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long value;
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int error;
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value = *(long *)arg1;
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error = sysctl_handle_long(oidp, &value, 0, req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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mtx_lock(&rbreqlock);
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if (arg1 == &hirunningspace) {
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if (value < lorunningspace)
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error = EINVAL;
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else
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hirunningspace = value;
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} else {
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KASSERT(arg1 == &lorunningspace,
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("%s: unknown arg1", __func__));
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if (value > hirunningspace)
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error = EINVAL;
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else
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lorunningspace = value;
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}
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mtx_unlock(&rbreqlock);
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return (error);
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}
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#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
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defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
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static int
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sysctl_bufspace(SYSCTL_HANDLER_ARGS)
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{
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long lvalue;
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int ivalue;
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if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long))
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return (sysctl_handle_long(oidp, arg1, arg2, req));
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lvalue = *(long *)arg1;
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if (lvalue > INT_MAX)
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/* On overflow, still write out a long to trigger ENOMEM. */
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return (sysctl_handle_long(oidp, &lvalue, 0, req));
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ivalue = lvalue;
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return (sysctl_handle_int(oidp, &ivalue, 0, req));
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}
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#endif
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static int
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bqcleanq(void)
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{
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static int nextq;
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return ((atomic_fetchadd_int(&nextq, 1) % clean_queues) + QUEUE_CLEAN);
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}
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static int
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bqisclean(int qindex)
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{
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return (qindex >= QUEUE_CLEAN && qindex < QUEUE_CLEAN + CLEAN_QUEUES);
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}
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/*
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* bqlock:
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*
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* Return the appropriate queue lock based on the index.
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*/
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static inline struct mtx *
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bqlock(int qindex)
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{
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return (struct mtx *)&bqlocks[qindex];
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}
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/*
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* bdirtywakeup:
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*
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* Wakeup any bwillwrite() waiters.
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*/
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static void
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bdirtywakeup(void)
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{
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mtx_lock(&bdirtylock);
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if (bdirtywait) {
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bdirtywait = 0;
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wakeup(&bdirtywait);
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}
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mtx_unlock(&bdirtylock);
|
|
}
|
|
|
|
/*
|
|
* bdirtysub:
|
|
*
|
|
* Decrement the numdirtybuffers count by one and wakeup any
|
|
* threads blocked in bwillwrite().
|
|
*/
|
|
static void
|
|
bdirtysub(void)
|
|
{
|
|
|
|
if (atomic_fetchadd_int(&numdirtybuffers, -1) ==
|
|
(lodirtybuffers + hidirtybuffers) / 2)
|
|
bdirtywakeup();
|
|
}
|
|
|
|
/*
|
|
* bdirtyadd:
|
|
*
|
|
* Increment the numdirtybuffers count by one and wakeup the buf
|
|
* daemon if needed.
|
|
*/
|
|
static void
|
|
bdirtyadd(void)
|
|
{
|
|
|
|
/*
|
|
* Only do the wakeup once as we cross the boundary. The
|
|
* buf daemon will keep running until the condition clears.
|
|
*/
|
|
if (atomic_fetchadd_int(&numdirtybuffers, 1) ==
|
|
(lodirtybuffers + hidirtybuffers) / 2)
|
|
bd_wakeup();
|
|
}
|
|
|
|
/*
|
|
* bufspace_wakeup:
|
|
*
|
|
* Called when buffer space is potentially available for recovery.
|
|
* getnewbuf() will block on this flag when it is unable to free
|
|
* sufficient buffer space. Buffer space becomes recoverable when
|
|
* bp's get placed back in the queues.
|
|
*/
|
|
static void
|
|
bufspace_wakeup(void)
|
|
{
|
|
|
|
/*
|
|
* If someone is waiting for bufspace, wake them up.
|
|
*
|
|
* Since needsbuffer is set prior to doing an additional queue
|
|
* scan it is safe to check for the flag prior to acquiring the
|
|
* lock. The thread that is preparing to scan again before
|
|
* blocking would discover the buf we released.
|
|
*/
|
|
if (needsbuffer) {
|
|
rw_rlock(&nblock);
|
|
if (atomic_cmpset_int(&needsbuffer, 1, 0) == 1)
|
|
wakeup(__DEVOLATILE(void *, &needsbuffer));
|
|
rw_runlock(&nblock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* bufspace_daemonwakeup:
|
|
*
|
|
* Wakeup the daemon responsible for freeing clean bufs.
|
|
*/
|
|
static void
|
|
bufspace_daemonwakeup(void)
|
|
{
|
|
rw_rlock(&nblock);
|
|
if (bufspace_request == 0) {
|
|
bufspace_request = 1;
|
|
wakeup(&bufspace_request);
|
|
}
|
|
rw_runlock(&nblock);
|
|
}
|
|
|
|
/*
|
|
* bufspace_adjust:
|
|
*
|
|
* Adjust the reported bufspace for a KVA managed buffer, possibly
|
|
* waking any waiters.
|
|
*/
|
|
static void
|
|
bufspace_adjust(struct buf *bp, int bufsize)
|
|
{
|
|
long space;
|
|
int diff;
|
|
|
|
KASSERT((bp->b_flags & B_MALLOC) == 0,
|
|
("bufspace_adjust: malloc buf %p", bp));
|
|
diff = bufsize - bp->b_bufsize;
|
|
if (diff < 0) {
|
|
atomic_subtract_long(&bufspace, -diff);
|
|
bufspace_wakeup();
|
|
} else {
|
|
space = atomic_fetchadd_long(&bufspace, diff);
|
|
/* Wake up the daemon on the transition. */
|
|
if (space < bufspacethresh && space + diff >= bufspacethresh)
|
|
bufspace_daemonwakeup();
|
|
}
|
|
bp->b_bufsize = bufsize;
|
|
}
|
|
|
|
/*
|
|
* bufspace_reserve:
|
|
*
|
|
* Reserve bufspace before calling allocbuf(). metadata has a
|
|
* different space limit than data.
|
|
*/
|
|
static int
|
|
bufspace_reserve(int size, bool metadata)
|
|
{
|
|
long limit;
|
|
long space;
|
|
|
|
if (metadata)
|
|
limit = maxbufspace;
|
|
else
|
|
limit = hibufspace;
|
|
do {
|
|
space = bufspace;
|
|
if (space + size > limit)
|
|
return (ENOSPC);
|
|
} while (atomic_cmpset_long(&bufspace, space, space + size) == 0);
|
|
|
|
/* Wake up the daemon on the transition. */
|
|
if (space < bufspacethresh && space + size >= bufspacethresh)
|
|
bufspace_daemonwakeup();
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* bufspace_release:
|
|
*
|
|
* Release reserved bufspace after bufspace_adjust() has consumed it.
|
|
*/
|
|
static void
|
|
bufspace_release(int size)
|
|
{
|
|
atomic_subtract_long(&bufspace, size);
|
|
bufspace_wakeup();
|
|
}
|
|
|
|
/*
|
|
* bufspace_wait:
|
|
*
|
|
* Wait for bufspace, acting as the buf daemon if a locked vnode is
|
|
* supplied. needsbuffer must be set in a safe fashion prior to
|
|
* polling for space. The operation must be re-tried on return.
|
|
*/
|
|
static void
|
|
bufspace_wait(struct vnode *vp, int gbflags, int slpflag, int slptimeo)
|
|
{
|
|
struct thread *td;
|
|
int error, fl, norunbuf;
|
|
|
|
if ((gbflags & GB_NOWAIT_BD) != 0)
|
|
return;
|
|
|
|
td = curthread;
|
|
rw_wlock(&nblock);
|
|
while (needsbuffer != 0) {
|
|
if (vp != NULL && vp->v_type != VCHR &&
|
|
(td->td_pflags & TDP_BUFNEED) == 0) {
|
|
rw_wunlock(&nblock);
|
|
/*
|
|
* getblk() is called with a vnode locked, and
|
|
* some majority of the dirty buffers may as
|
|
* well belong to the vnode. Flushing the
|
|
* buffers there would make a progress that
|
|
* cannot be achieved by the buf_daemon, that
|
|
* cannot lock the vnode.
|
|
*/
|
|
norunbuf = ~(TDP_BUFNEED | TDP_NORUNNINGBUF) |
|
|
(td->td_pflags & TDP_NORUNNINGBUF);
|
|
|
|
/*
|
|
* Play bufdaemon. The getnewbuf() function
|
|
* may be called while the thread owns lock
|
|
* for another dirty buffer for the same
|
|
* vnode, which makes it impossible to use
|
|
* VOP_FSYNC() there, due to the buffer lock
|
|
* recursion.
|
|
*/
|
|
td->td_pflags |= TDP_BUFNEED | TDP_NORUNNINGBUF;
|
|
fl = buf_flush(vp, flushbufqtarget);
|
|
td->td_pflags &= norunbuf;
|
|
rw_wlock(&nblock);
|
|
if (fl != 0)
|
|
continue;
|
|
if (needsbuffer == 0)
|
|
break;
|
|
}
|
|
error = rw_sleep(__DEVOLATILE(void *, &needsbuffer), &nblock,
|
|
(PRIBIO + 4) | slpflag, "newbuf", slptimeo);
|
|
if (error != 0)
|
|
break;
|
|
}
|
|
rw_wunlock(&nblock);
|
|
}
|
|
|
|
|
|
/*
|
|
* bufspace_daemon:
|
|
*
|
|
* buffer space management daemon. Tries to maintain some marginal
|
|
* amount of free buffer space so that requesting processes neither
|
|
* block nor work to reclaim buffers.
|
|
*/
|
|
static void
|
|
bufspace_daemon(void)
|
|
{
|
|
for (;;) {
|
|
kproc_suspend_check(bufspacedaemonproc);
|
|
|
|
/*
|
|
* Free buffers from the clean queue until we meet our
|
|
* targets.
|
|
*
|
|
* Theory of operation: The buffer cache is most efficient
|
|
* when some free buffer headers and space are always
|
|
* available to getnewbuf(). This daemon attempts to prevent
|
|
* the excessive blocking and synchronization associated
|
|
* with shortfall. It goes through three phases according
|
|
* demand:
|
|
*
|
|
* 1) The daemon wakes up voluntarily once per-second
|
|
* during idle periods when the counters are below
|
|
* the wakeup thresholds (bufspacethresh, lofreebuffers).
|
|
*
|
|
* 2) The daemon wakes up as we cross the thresholds
|
|
* ahead of any potential blocking. This may bounce
|
|
* slightly according to the rate of consumption and
|
|
* release.
|
|
*
|
|
* 3) The daemon and consumers are starved for working
|
|
* clean buffers. This is the 'bufspace' sleep below
|
|
* which will inefficiently trade bufs with bqrelse
|
|
* until we return to condition 2.
|
|
*/
|
|
while (bufspace > lobufspace ||
|
|
numfreebuffers < hifreebuffers) {
|
|
if (buf_recycle(false) != 0) {
|
|
atomic_set_int(&needsbuffer, 1);
|
|
if (buf_recycle(false) != 0) {
|
|
rw_wlock(&nblock);
|
|
if (needsbuffer)
|
|
rw_sleep(__DEVOLATILE(void *,
|
|
&needsbuffer), &nblock,
|
|
PRIBIO|PDROP, "bufspace",
|
|
hz/10);
|
|
else
|
|
rw_wunlock(&nblock);
|
|
}
|
|
}
|
|
maybe_yield();
|
|
}
|
|
|
|
/*
|
|
* Re-check our limits under the exclusive nblock.
|
|
*/
|
|
rw_wlock(&nblock);
|
|
if (bufspace < bufspacethresh &&
|
|
numfreebuffers > lofreebuffers) {
|
|
bufspace_request = 0;
|
|
rw_sleep(&bufspace_request, &nblock, PRIBIO|PDROP,
|
|
"-", hz);
|
|
} else
|
|
rw_wunlock(&nblock);
|
|
}
|
|
}
|
|
|
|
static struct kproc_desc bufspace_kp = {
|
|
"bufspacedaemon",
|
|
bufspace_daemon,
|
|
&bufspacedaemonproc
|
|
};
|
|
SYSINIT(bufspacedaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start,
|
|
&bufspace_kp);
|
|
|
|
/*
|
|
* bufmallocadjust:
|
|
*
|
|
* Adjust the reported bufspace for a malloc managed buffer, possibly
|
|
* waking any waiters.
|
|
*/
|
|
static void
|
|
bufmallocadjust(struct buf *bp, int bufsize)
|
|
{
|
|
int diff;
|
|
|
|
KASSERT((bp->b_flags & B_MALLOC) != 0,
|
|
("bufmallocadjust: non-malloc buf %p", bp));
|
|
diff = bufsize - bp->b_bufsize;
|
|
if (diff < 0)
|
|
atomic_subtract_long(&bufmallocspace, -diff);
|
|
else
|
|
atomic_add_long(&bufmallocspace, diff);
|
|
bp->b_bufsize = bufsize;
|
|
}
|
|
|
|
/*
|
|
* runningwakeup:
|
|
*
|
|
* Wake up processes that are waiting on asynchronous writes to fall
|
|
* below lorunningspace.
|
|
*/
|
|
static void
|
|
runningwakeup(void)
|
|
{
|
|
|
|
mtx_lock(&rbreqlock);
|
|
if (runningbufreq) {
|
|
runningbufreq = 0;
|
|
wakeup(&runningbufreq);
|
|
}
|
|
mtx_unlock(&rbreqlock);
|
|
}
|
|
|
|
/*
|
|
* runningbufwakeup:
|
|
*
|
|
* Decrement the outstanding write count according.
|
|
*/
|
|
void
|
|
runningbufwakeup(struct buf *bp)
|
|
{
|
|
long space, bspace;
|
|
|
|
bspace = bp->b_runningbufspace;
|
|
if (bspace == 0)
|
|
return;
|
|
space = atomic_fetchadd_long(&runningbufspace, -bspace);
|
|
KASSERT(space >= bspace, ("runningbufspace underflow %ld %ld",
|
|
space, bspace));
|
|
bp->b_runningbufspace = 0;
|
|
/*
|
|
* Only acquire the lock and wakeup on the transition from exceeding
|
|
* the threshold to falling below it.
|
|
*/
|
|
if (space < lorunningspace)
|
|
return;
|
|
if (space - bspace > lorunningspace)
|
|
return;
|
|
runningwakeup();
|
|
}
|
|
|
|
/*
|
|
* waitrunningbufspace()
|
|
*
|
|
* runningbufspace is a measure of the amount of I/O currently
|
|
* running. This routine is used in async-write situations to
|
|
* prevent creating huge backups of pending writes to a device.
|
|
* Only asynchronous writes are governed by this function.
|
|
*
|
|
* This does NOT turn an async write into a sync write. It waits
|
|
* for earlier writes to complete and generally returns before the
|
|
* caller's write has reached the device.
|
|
*/
|
|
void
|
|
waitrunningbufspace(void)
|
|
{
|
|
|
|
mtx_lock(&rbreqlock);
|
|
while (runningbufspace > hirunningspace) {
|
|
runningbufreq = 1;
|
|
msleep(&runningbufreq, &rbreqlock, PVM, "wdrain", 0);
|
|
}
|
|
mtx_unlock(&rbreqlock);
|
|
}
|
|
|
|
|
|
/*
|
|
* vfs_buf_test_cache:
|
|
*
|
|
* Called when a buffer is extended. This function clears the B_CACHE
|
|
* bit if the newly extended portion of the buffer does not contain
|
|
* valid data.
|
|
*/
|
|
static __inline void
|
|
vfs_buf_test_cache(struct buf *bp, vm_ooffset_t foff, vm_offset_t off,
|
|
vm_offset_t size, vm_page_t m)
|
|
{
|
|
|
|
VM_OBJECT_ASSERT_LOCKED(m->object);
|
|
if (bp->b_flags & B_CACHE) {
|
|
int base = (foff + off) & PAGE_MASK;
|
|
if (vm_page_is_valid(m, base, size) == 0)
|
|
bp->b_flags &= ~B_CACHE;
|
|
}
|
|
}
|
|
|
|
/* Wake up the buffer daemon if necessary */
|
|
static __inline void
|
|
bd_wakeup(void)
|
|
{
|
|
|
|
mtx_lock(&bdlock);
|
|
if (bd_request == 0) {
|
|
bd_request = 1;
|
|
wakeup(&bd_request);
|
|
}
|
|
mtx_unlock(&bdlock);
|
|
}
|
|
|
|
/*
|
|
* bd_speedup - speedup the buffer cache flushing code
|
|
*/
|
|
void
|
|
bd_speedup(void)
|
|
{
|
|
int needwake;
|
|
|
|
mtx_lock(&bdlock);
|
|
needwake = 0;
|
|
if (bd_speedupreq == 0 || bd_request == 0)
|
|
needwake = 1;
|
|
bd_speedupreq = 1;
|
|
bd_request = 1;
|
|
if (needwake)
|
|
wakeup(&bd_request);
|
|
mtx_unlock(&bdlock);
|
|
}
|
|
|
|
#ifndef NSWBUF_MIN
|
|
#define NSWBUF_MIN 16
|
|
#endif
|
|
|
|
#ifdef __i386__
|
|
#define TRANSIENT_DENOM 5
|
|
#else
|
|
#define TRANSIENT_DENOM 10
|
|
#endif
|
|
|
|
/*
|
|
* Calculating buffer cache scaling values and reserve space for buffer
|
|
* headers. This is called during low level kernel initialization and
|
|
* may be called more then once. We CANNOT write to the memory area
|
|
* being reserved at this time.
|
|
*/
|
|
caddr_t
|
|
kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est)
|
|
{
|
|
int tuned_nbuf;
|
|
long maxbuf, maxbuf_sz, buf_sz, biotmap_sz;
|
|
|
|
/*
|
|
* physmem_est is in pages. Convert it to kilobytes (assumes
|
|
* PAGE_SIZE is >= 1K)
|
|
*/
|
|
physmem_est = physmem_est * (PAGE_SIZE / 1024);
|
|
|
|
/*
|
|
* The nominal buffer size (and minimum KVA allocation) is BKVASIZE.
|
|
* For the first 64MB of ram nominally allocate sufficient buffers to
|
|
* cover 1/4 of our ram. Beyond the first 64MB allocate additional
|
|
* buffers to cover 1/10 of our ram over 64MB. When auto-sizing
|
|
* the buffer cache we limit the eventual kva reservation to
|
|
* maxbcache bytes.
|
|
*
|
|
* factor represents the 1/4 x ram conversion.
|
|
*/
|
|
if (nbuf == 0) {
|
|
int factor = 4 * BKVASIZE / 1024;
|
|
|
|
nbuf = 50;
|
|
if (physmem_est > 4096)
|
|
nbuf += min((physmem_est - 4096) / factor,
|
|
65536 / factor);
|
|
if (physmem_est > 65536)
|
|
nbuf += min((physmem_est - 65536) * 2 / (factor * 5),
|
|
32 * 1024 * 1024 / (factor * 5));
|
|
|
|
if (maxbcache && nbuf > maxbcache / BKVASIZE)
|
|
nbuf = maxbcache / BKVASIZE;
|
|
tuned_nbuf = 1;
|
|
} else
|
|
tuned_nbuf = 0;
|
|
|
|
/* XXX Avoid unsigned long overflows later on with maxbufspace. */
|
|
maxbuf = (LONG_MAX / 3) / BKVASIZE;
|
|
if (nbuf > maxbuf) {
|
|
if (!tuned_nbuf)
|
|
printf("Warning: nbufs lowered from %d to %ld\n", nbuf,
|
|
maxbuf);
|
|
nbuf = maxbuf;
|
|
}
|
|
|
|
/*
|
|
* Ideal allocation size for the transient bio submap is 10%
|
|
* of the maximal space buffer map. This roughly corresponds
|
|
* to the amount of the buffer mapped for typical UFS load.
|
|
*
|
|
* Clip the buffer map to reserve space for the transient
|
|
* BIOs, if its extent is bigger than 90% (80% on i386) of the
|
|
* maximum buffer map extent on the platform.
|
|
*
|
|
* The fall-back to the maxbuf in case of maxbcache unset,
|
|
* allows to not trim the buffer KVA for the architectures
|
|
* with ample KVA space.
|
|
*/
|
|
if (bio_transient_maxcnt == 0 && unmapped_buf_allowed) {
|
|
maxbuf_sz = maxbcache != 0 ? maxbcache : maxbuf * BKVASIZE;
|
|
buf_sz = (long)nbuf * BKVASIZE;
|
|
if (buf_sz < maxbuf_sz / TRANSIENT_DENOM *
|
|
(TRANSIENT_DENOM - 1)) {
|
|
/*
|
|
* There is more KVA than memory. Do not
|
|
* adjust buffer map size, and assign the rest
|
|
* of maxbuf to transient map.
|
|
*/
|
|
biotmap_sz = maxbuf_sz - buf_sz;
|
|
} else {
|
|
/*
|
|
* Buffer map spans all KVA we could afford on
|
|
* this platform. Give 10% (20% on i386) of
|
|
* the buffer map to the transient bio map.
|
|
*/
|
|
biotmap_sz = buf_sz / TRANSIENT_DENOM;
|
|
buf_sz -= biotmap_sz;
|
|
}
|
|
if (biotmap_sz / INT_MAX > MAXPHYS)
|
|
bio_transient_maxcnt = INT_MAX;
|
|
else
|
|
bio_transient_maxcnt = biotmap_sz / MAXPHYS;
|
|
/*
|
|
* Artificially limit to 1024 simultaneous in-flight I/Os
|
|
* using the transient mapping.
|
|
*/
|
|
if (bio_transient_maxcnt > 1024)
|
|
bio_transient_maxcnt = 1024;
|
|
if (tuned_nbuf)
|
|
nbuf = buf_sz / BKVASIZE;
|
|
}
|
|
|
|
/*
|
|
* swbufs are used as temporary holders for I/O, such as paging I/O.
|
|
* We have no less then 16 and no more then 256.
|
|
*/
|
|
nswbuf = min(nbuf / 4, 256);
|
|
TUNABLE_INT_FETCH("kern.nswbuf", &nswbuf);
|
|
if (nswbuf < NSWBUF_MIN)
|
|
nswbuf = NSWBUF_MIN;
|
|
|
|
/*
|
|
* Reserve space for the buffer cache buffers
|
|
*/
|
|
swbuf = (void *)v;
|
|
v = (caddr_t)(swbuf + nswbuf);
|
|
buf = (void *)v;
|
|
v = (caddr_t)(buf + nbuf);
|
|
|
|
return(v);
|
|
}
|
|
|
|
/* Initialize the buffer subsystem. Called before use of any buffers. */
|
|
void
|
|
bufinit(void)
|
|
{
|
|
struct buf *bp;
|
|
int i;
|
|
|
|
CTASSERT(MAXBCACHEBUF >= MAXBSIZE);
|
|
mtx_init(&bqlocks[QUEUE_DIRTY], "bufq dirty lock", NULL, MTX_DEF);
|
|
mtx_init(&bqlocks[QUEUE_EMPTY], "bufq empty lock", NULL, MTX_DEF);
|
|
for (i = QUEUE_CLEAN; i < QUEUE_CLEAN + CLEAN_QUEUES; i++)
|
|
mtx_init(&bqlocks[i], "bufq clean lock", NULL, MTX_DEF);
|
|
mtx_init(&rbreqlock, "runningbufspace lock", NULL, MTX_DEF);
|
|
rw_init(&nblock, "needsbuffer lock");
|
|
mtx_init(&bdlock, "buffer daemon lock", NULL, MTX_DEF);
|
|
mtx_init(&bdirtylock, "dirty buf lock", NULL, MTX_DEF);
|
|
|
|
/* next, make a null set of free lists */
|
|
for (i = 0; i < BUFFER_QUEUES; i++)
|
|
TAILQ_INIT(&bufqueues[i]);
|
|
|
|
unmapped_buf = (caddr_t)kva_alloc(MAXPHYS);
|
|
|
|
/* finally, initialize each buffer header and stick on empty q */
|
|
for (i = 0; i < nbuf; i++) {
|
|
bp = &buf[i];
|
|
bzero(bp, sizeof *bp);
|
|
bp->b_flags = B_INVAL;
|
|
bp->b_rcred = NOCRED;
|
|
bp->b_wcred = NOCRED;
|
|
bp->b_qindex = QUEUE_EMPTY;
|
|
bp->b_xflags = 0;
|
|
bp->b_data = bp->b_kvabase = unmapped_buf;
|
|
LIST_INIT(&bp->b_dep);
|
|
BUF_LOCKINIT(bp);
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
|
|
#ifdef INVARIANTS
|
|
bq_len[QUEUE_EMPTY]++;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* maxbufspace is the absolute maximum amount of buffer space we are
|
|
* allowed to reserve in KVM and in real terms. The absolute maximum
|
|
* is nominally used by metadata. hibufspace is the nominal maximum
|
|
* used by most other requests. The differential is required to
|
|
* ensure that metadata deadlocks don't occur.
|
|
*
|
|
* maxbufspace is based on BKVASIZE. Allocating buffers larger then
|
|
* this may result in KVM fragmentation which is not handled optimally
|
|
* by the system. XXX This is less true with vmem. We could use
|
|
* PAGE_SIZE.
|
|
*/
|
|
maxbufspace = (long)nbuf * BKVASIZE;
|
|
hibufspace = lmax(3 * maxbufspace / 4, maxbufspace - MAXBCACHEBUF * 10);
|
|
lobufspace = (hibufspace / 20) * 19; /* 95% */
|
|
bufspacethresh = lobufspace + (hibufspace - lobufspace) / 2;
|
|
|
|
/*
|
|
* Note: The 16 MiB upper limit for hirunningspace was chosen
|
|
* arbitrarily and may need further tuning. It corresponds to
|
|
* 128 outstanding write IO requests (if IO size is 128 KiB),
|
|
* which fits with many RAID controllers' tagged queuing limits.
|
|
* The lower 1 MiB limit is the historical upper limit for
|
|
* hirunningspace.
|
|
*/
|
|
hirunningspace = lmax(lmin(roundup(hibufspace / 64, MAXBCACHEBUF),
|
|
16 * 1024 * 1024), 1024 * 1024);
|
|
lorunningspace = roundup((hirunningspace * 2) / 3, MAXBCACHEBUF);
|
|
|
|
/*
|
|
* Limit the amount of malloc memory since it is wired permanently into
|
|
* the kernel space. Even though this is accounted for in the buffer
|
|
* allocation, we don't want the malloced region to grow uncontrolled.
|
|
* The malloc scheme improves memory utilization significantly on
|
|
* average (small) directories.
|
|
*/
|
|
maxbufmallocspace = hibufspace / 20;
|
|
|
|
/*
|
|
* Reduce the chance of a deadlock occurring by limiting the number
|
|
* of delayed-write dirty buffers we allow to stack up.
|
|
*/
|
|
hidirtybuffers = nbuf / 4 + 20;
|
|
dirtybufthresh = hidirtybuffers * 9 / 10;
|
|
numdirtybuffers = 0;
|
|
/*
|
|
* To support extreme low-memory systems, make sure hidirtybuffers
|
|
* cannot eat up all available buffer space. This occurs when our
|
|
* minimum cannot be met. We try to size hidirtybuffers to 3/4 our
|
|
* buffer space assuming BKVASIZE'd buffers.
|
|
*/
|
|
while ((long)hidirtybuffers * BKVASIZE > 3 * hibufspace / 4) {
|
|
hidirtybuffers >>= 1;
|
|
}
|
|
lodirtybuffers = hidirtybuffers / 2;
|
|
|
|
/*
|
|
* lofreebuffers should be sufficient to avoid stalling waiting on
|
|
* buf headers under heavy utilization. The bufs in per-cpu caches
|
|
* are counted as free but will be unavailable to threads executing
|
|
* on other cpus.
|
|
*
|
|
* hifreebuffers is the free target for the bufspace daemon. This
|
|
* should be set appropriately to limit work per-iteration.
|
|
*/
|
|
lofreebuffers = MIN((nbuf / 25) + (20 * mp_ncpus), 128 * mp_ncpus);
|
|
hifreebuffers = (3 * lofreebuffers) / 2;
|
|
numfreebuffers = nbuf;
|
|
|
|
bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ |
|
|
VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
|
|
|
|
/* Setup the kva and free list allocators. */
|
|
vmem_set_reclaim(buffer_arena, bufkva_reclaim);
|
|
buf_zone = uma_zcache_create("buf free cache", sizeof(struct buf),
|
|
NULL, NULL, NULL, NULL, buf_import, buf_release, NULL, 0);
|
|
|
|
/*
|
|
* Size the clean queue according to the amount of buffer space.
|
|
* One queue per-256mb up to the max. More queues gives better
|
|
* concurrency but less accurate LRU.
|
|
*/
|
|
clean_queues = MIN(howmany(maxbufspace, 256*1024*1024), CLEAN_QUEUES);
|
|
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
static inline void
|
|
vfs_buf_check_mapped(struct buf *bp)
|
|
{
|
|
|
|
KASSERT(bp->b_kvabase != unmapped_buf,
|
|
("mapped buf: b_kvabase was not updated %p", bp));
|
|
KASSERT(bp->b_data != unmapped_buf,
|
|
("mapped buf: b_data was not updated %p", bp));
|
|
KASSERT(bp->b_data < unmapped_buf || bp->b_data >= unmapped_buf +
|
|
MAXPHYS, ("b_data + b_offset unmapped %p", bp));
|
|
}
|
|
|
|
static inline void
|
|
vfs_buf_check_unmapped(struct buf *bp)
|
|
{
|
|
|
|
KASSERT(bp->b_data == unmapped_buf,
|
|
("unmapped buf: corrupted b_data %p", bp));
|
|
}
|
|
|
|
#define BUF_CHECK_MAPPED(bp) vfs_buf_check_mapped(bp)
|
|
#define BUF_CHECK_UNMAPPED(bp) vfs_buf_check_unmapped(bp)
|
|
#else
|
|
#define BUF_CHECK_MAPPED(bp) do {} while (0)
|
|
#define BUF_CHECK_UNMAPPED(bp) do {} while (0)
|
|
#endif
|
|
|
|
static int
|
|
isbufbusy(struct buf *bp)
|
|
{
|
|
if (((bp->b_flags & B_INVAL) == 0 && BUF_ISLOCKED(bp)) ||
|
|
((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI))
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Shutdown the system cleanly to prepare for reboot, halt, or power off.
|
|
*/
|
|
void
|
|
bufshutdown(int show_busybufs)
|
|
{
|
|
static int first_buf_printf = 1;
|
|
struct buf *bp;
|
|
int iter, nbusy, pbusy;
|
|
#ifndef PREEMPTION
|
|
int subiter;
|
|
#endif
|
|
|
|
/*
|
|
* Sync filesystems for shutdown
|
|
*/
|
|
wdog_kern_pat(WD_LASTVAL);
|
|
sys_sync(curthread, NULL);
|
|
|
|
/*
|
|
* With soft updates, some buffers that are
|
|
* written will be remarked as dirty until other
|
|
* buffers are written.
|
|
*/
|
|
for (iter = pbusy = 0; iter < 20; iter++) {
|
|
nbusy = 0;
|
|
for (bp = &buf[nbuf]; --bp >= buf; )
|
|
if (isbufbusy(bp))
|
|
nbusy++;
|
|
if (nbusy == 0) {
|
|
if (first_buf_printf)
|
|
printf("All buffers synced.");
|
|
break;
|
|
}
|
|
if (first_buf_printf) {
|
|
printf("Syncing disks, buffers remaining... ");
|
|
first_buf_printf = 0;
|
|
}
|
|
printf("%d ", nbusy);
|
|
if (nbusy < pbusy)
|
|
iter = 0;
|
|
pbusy = nbusy;
|
|
|
|
wdog_kern_pat(WD_LASTVAL);
|
|
sys_sync(curthread, NULL);
|
|
|
|
#ifdef PREEMPTION
|
|
/*
|
|
* Drop Giant and spin for a while to allow
|
|
* interrupt threads to run.
|
|
*/
|
|
DROP_GIANT();
|
|
DELAY(50000 * iter);
|
|
PICKUP_GIANT();
|
|
#else
|
|
/*
|
|
* Drop Giant and context switch several times to
|
|
* allow interrupt threads to run.
|
|
*/
|
|
DROP_GIANT();
|
|
for (subiter = 0; subiter < 50 * iter; subiter++) {
|
|
thread_lock(curthread);
|
|
mi_switch(SW_VOL, NULL);
|
|
thread_unlock(curthread);
|
|
DELAY(1000);
|
|
}
|
|
PICKUP_GIANT();
|
|
#endif
|
|
}
|
|
printf("\n");
|
|
/*
|
|
* Count only busy local buffers to prevent forcing
|
|
* a fsck if we're just a client of a wedged NFS server
|
|
*/
|
|
nbusy = 0;
|
|
for (bp = &buf[nbuf]; --bp >= buf; ) {
|
|
if (isbufbusy(bp)) {
|
|
#if 0
|
|
/* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */
|
|
if (bp->b_dev == NULL) {
|
|
TAILQ_REMOVE(&mountlist,
|
|
bp->b_vp->v_mount, mnt_list);
|
|
continue;
|
|
}
|
|
#endif
|
|
nbusy++;
|
|
if (show_busybufs > 0) {
|
|
printf(
|
|
"%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:",
|
|
nbusy, bp, bp->b_vp, bp->b_flags,
|
|
(intmax_t)bp->b_blkno,
|
|
(intmax_t)bp->b_lblkno);
|
|
BUF_LOCKPRINTINFO(bp);
|
|
if (show_busybufs > 1)
|
|
vn_printf(bp->b_vp,
|
|
"vnode content: ");
|
|
}
|
|
}
|
|
}
|
|
if (nbusy) {
|
|
/*
|
|
* Failed to sync all blocks. Indicate this and don't
|
|
* unmount filesystems (thus forcing an fsck on reboot).
|
|
*/
|
|
printf("Giving up on %d buffers\n", nbusy);
|
|
DELAY(5000000); /* 5 seconds */
|
|
} else {
|
|
if (!first_buf_printf)
|
|
printf("Final sync complete\n");
|
|
/*
|
|
* Unmount filesystems
|
|
*/
|
|
if (panicstr == NULL)
|
|
vfs_unmountall();
|
|
}
|
|
swapoff_all();
|
|
DELAY(100000); /* wait for console output to finish */
|
|
}
|
|
|
|
static void
|
|
bpmap_qenter(struct buf *bp)
|
|
{
|
|
|
|
BUF_CHECK_MAPPED(bp);
|
|
|
|
/*
|
|
* bp->b_data is relative to bp->b_offset, but
|
|
* bp->b_offset may be offset into the first page.
|
|
*/
|
|
bp->b_data = (caddr_t)trunc_page((vm_offset_t)bp->b_data);
|
|
pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
|
|
bp->b_data = (caddr_t)((vm_offset_t)bp->b_data |
|
|
(vm_offset_t)(bp->b_offset & PAGE_MASK));
|
|
}
|
|
|
|
/*
|
|
* binsfree:
|
|
*
|
|
* Insert the buffer into the appropriate free list.
|
|
*/
|
|
static void
|
|
binsfree(struct buf *bp, int qindex)
|
|
{
|
|
struct mtx *olock, *nlock;
|
|
|
|
if (qindex != QUEUE_EMPTY) {
|
|
BUF_ASSERT_XLOCKED(bp);
|
|
}
|
|
|
|
/*
|
|
* Stick to the same clean queue for the lifetime of the buf to
|
|
* limit locking below. Otherwise pick ont sequentially.
|
|
*/
|
|
if (qindex == QUEUE_CLEAN) {
|
|
if (bqisclean(bp->b_qindex))
|
|
qindex = bp->b_qindex;
|
|
else
|
|
qindex = bqcleanq();
|
|
}
|
|
|
|
/*
|
|
* Handle delayed bremfree() processing.
|
|
*/
|
|
nlock = bqlock(qindex);
|
|
if (bp->b_flags & B_REMFREE) {
|
|
olock = bqlock(bp->b_qindex);
|
|
mtx_lock(olock);
|
|
bremfreel(bp);
|
|
if (olock != nlock) {
|
|
mtx_unlock(olock);
|
|
mtx_lock(nlock);
|
|
}
|
|
} else
|
|
mtx_lock(nlock);
|
|
|
|
if (bp->b_qindex != QUEUE_NONE)
|
|
panic("binsfree: free buffer onto another queue???");
|
|
|
|
bp->b_qindex = qindex;
|
|
if (bp->b_flags & B_AGE)
|
|
TAILQ_INSERT_HEAD(&bufqueues[bp->b_qindex], bp, b_freelist);
|
|
else
|
|
TAILQ_INSERT_TAIL(&bufqueues[bp->b_qindex], bp, b_freelist);
|
|
#ifdef INVARIANTS
|
|
bq_len[bp->b_qindex]++;
|
|
#endif
|
|
mtx_unlock(nlock);
|
|
}
|
|
|
|
/*
|
|
* buf_free:
|
|
*
|
|
* Free a buffer to the buf zone once it no longer has valid contents.
|
|
*/
|
|
static void
|
|
buf_free(struct buf *bp)
|
|
{
|
|
|
|
if (bp->b_flags & B_REMFREE)
|
|
bremfreef(bp);
|
|
if (bp->b_vflags & BV_BKGRDINPROG)
|
|
panic("losing buffer 1");
|
|
if (bp->b_rcred != NOCRED) {
|
|
crfree(bp->b_rcred);
|
|
bp->b_rcred = NOCRED;
|
|
}
|
|
if (bp->b_wcred != NOCRED) {
|
|
crfree(bp->b_wcred);
|
|
bp->b_wcred = NOCRED;
|
|
}
|
|
if (!LIST_EMPTY(&bp->b_dep))
|
|
buf_deallocate(bp);
|
|
bufkva_free(bp);
|
|
BUF_UNLOCK(bp);
|
|
uma_zfree(buf_zone, bp);
|
|
atomic_add_int(&numfreebuffers, 1);
|
|
bufspace_wakeup();
|
|
}
|
|
|
|
/*
|
|
* buf_import:
|
|
*
|
|
* Import bufs into the uma cache from the buf list. The system still
|
|
* expects a static array of bufs and much of the synchronization
|
|
* around bufs assumes type stable storage. As a result, UMA is used
|
|
* only as a per-cpu cache of bufs still maintained on a global list.
|
|
*/
|
|
static int
|
|
buf_import(void *arg, void **store, int cnt, int flags)
|
|
{
|
|
struct buf *bp;
|
|
int i;
|
|
|
|
mtx_lock(&bqlocks[QUEUE_EMPTY]);
|
|
for (i = 0; i < cnt; i++) {
|
|
bp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]);
|
|
if (bp == NULL)
|
|
break;
|
|
bremfreel(bp);
|
|
store[i] = bp;
|
|
}
|
|
mtx_unlock(&bqlocks[QUEUE_EMPTY]);
|
|
|
|
return (i);
|
|
}
|
|
|
|
/*
|
|
* buf_release:
|
|
*
|
|
* Release bufs from the uma cache back to the buffer queues.
|
|
*/
|
|
static void
|
|
buf_release(void *arg, void **store, int cnt)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < cnt; i++)
|
|
binsfree(store[i], QUEUE_EMPTY);
|
|
}
|
|
|
|
/*
|
|
* buf_alloc:
|
|
*
|
|
* Allocate an empty buffer header.
|
|
*/
|
|
static struct buf *
|
|
buf_alloc(void)
|
|
{
|
|
struct buf *bp;
|
|
|
|
bp = uma_zalloc(buf_zone, M_NOWAIT);
|
|
if (bp == NULL) {
|
|
bufspace_daemonwakeup();
|
|
atomic_add_int(&numbufallocfails, 1);
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Wake-up the bufspace daemon on transition.
|
|
*/
|
|
if (atomic_fetchadd_int(&numfreebuffers, -1) == lofreebuffers)
|
|
bufspace_daemonwakeup();
|
|
|
|
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
|
|
panic("getnewbuf_empty: Locked buf %p on free queue.", bp);
|
|
|
|
KASSERT(bp->b_vp == NULL,
|
|
("bp: %p still has vnode %p.", bp, bp->b_vp));
|
|
KASSERT((bp->b_flags & (B_DELWRI | B_NOREUSE)) == 0,
|
|
("invalid buffer %p flags %#x", bp, bp->b_flags));
|
|
KASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0,
|
|
("bp: %p still on a buffer list. xflags %X", bp, bp->b_xflags));
|
|
KASSERT(bp->b_npages == 0,
|
|
("bp: %p still has %d vm pages\n", bp, bp->b_npages));
|
|
KASSERT(bp->b_kvasize == 0, ("bp: %p still has kva\n", bp));
|
|
KASSERT(bp->b_bufsize == 0, ("bp: %p still has bufspace\n", bp));
|
|
|
|
bp->b_flags = 0;
|
|
bp->b_ioflags = 0;
|
|
bp->b_xflags = 0;
|
|
bp->b_vflags = 0;
|
|
bp->b_vp = NULL;
|
|
bp->b_blkno = bp->b_lblkno = 0;
|
|
bp->b_offset = NOOFFSET;
|
|
bp->b_iodone = 0;
|
|
bp->b_error = 0;
|
|
bp->b_resid = 0;
|
|
bp->b_bcount = 0;
|
|
bp->b_npages = 0;
|
|
bp->b_dirtyoff = bp->b_dirtyend = 0;
|
|
bp->b_bufobj = NULL;
|
|
bp->b_data = bp->b_kvabase = unmapped_buf;
|
|
bp->b_fsprivate1 = NULL;
|
|
bp->b_fsprivate2 = NULL;
|
|
bp->b_fsprivate3 = NULL;
|
|
LIST_INIT(&bp->b_dep);
|
|
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* buf_qrecycle:
|
|
*
|
|
* Free a buffer from the given bufqueue. kva controls whether the
|
|
* freed buf must own some kva resources. This is used for
|
|
* defragmenting.
|
|
*/
|
|
static int
|
|
buf_qrecycle(int qindex, bool kva)
|
|
{
|
|
struct buf *bp, *nbp;
|
|
|
|
if (kva)
|
|
atomic_add_int(&bufdefragcnt, 1);
|
|
nbp = NULL;
|
|
mtx_lock(&bqlocks[qindex]);
|
|
nbp = TAILQ_FIRST(&bufqueues[qindex]);
|
|
|
|
/*
|
|
* Run scan, possibly freeing data and/or kva mappings on the fly
|
|
* depending.
|
|
*/
|
|
while ((bp = nbp) != NULL) {
|
|
/*
|
|
* Calculate next bp (we can only use it if we do not
|
|
* release the bqlock).
|
|
*/
|
|
nbp = TAILQ_NEXT(bp, b_freelist);
|
|
|
|
/*
|
|
* If we are defragging then we need a buffer with
|
|
* some kva to reclaim.
|
|
*/
|
|
if (kva && bp->b_kvasize == 0)
|
|
continue;
|
|
|
|
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
|
|
continue;
|
|
|
|
/*
|
|
* Skip buffers with background writes in progress.
|
|
*/
|
|
if ((bp->b_vflags & BV_BKGRDINPROG) != 0) {
|
|
BUF_UNLOCK(bp);
|
|
continue;
|
|
}
|
|
|
|
KASSERT(bp->b_qindex == qindex,
|
|
("getnewbuf: inconsistent queue %d bp %p", qindex, bp));
|
|
/*
|
|
* NOTE: nbp is now entirely invalid. We can only restart
|
|
* the scan from this point on.
|
|
*/
|
|
bremfreel(bp);
|
|
mtx_unlock(&bqlocks[qindex]);
|
|
|
|
/*
|
|
* Requeue the background write buffer with error and
|
|
* restart the scan.
|
|
*/
|
|
if ((bp->b_vflags & BV_BKGRDERR) != 0) {
|
|
bqrelse(bp);
|
|
mtx_lock(&bqlocks[qindex]);
|
|
nbp = TAILQ_FIRST(&bufqueues[qindex]);
|
|
continue;
|
|
}
|
|
bp->b_flags |= B_INVAL;
|
|
brelse(bp);
|
|
return (0);
|
|
}
|
|
mtx_unlock(&bqlocks[qindex]);
|
|
|
|
return (ENOBUFS);
|
|
}
|
|
|
|
/*
|
|
* buf_recycle:
|
|
*
|
|
* Iterate through all clean queues until we find a buf to recycle or
|
|
* exhaust the search.
|
|
*/
|
|
static int
|
|
buf_recycle(bool kva)
|
|
{
|
|
int qindex, first_qindex;
|
|
|
|
qindex = first_qindex = bqcleanq();
|
|
do {
|
|
if (buf_qrecycle(qindex, kva) == 0)
|
|
return (0);
|
|
if (++qindex == QUEUE_CLEAN + clean_queues)
|
|
qindex = QUEUE_CLEAN;
|
|
} while (qindex != first_qindex);
|
|
|
|
return (ENOBUFS);
|
|
}
|
|
|
|
/*
|
|
* buf_scan:
|
|
*
|
|
* Scan the clean queues looking for a buffer to recycle. needsbuffer
|
|
* is set on failure so that the caller may optionally bufspace_wait()
|
|
* in a race-free fashion.
|
|
*/
|
|
static int
|
|
buf_scan(bool defrag)
|
|
{
|
|
int error;
|
|
|
|
/*
|
|
* To avoid heavy synchronization and wakeup races we set
|
|
* needsbuffer and re-poll before failing. This ensures that
|
|
* no frees can be missed between an unsuccessful poll and
|
|
* going to sleep in a synchronized fashion.
|
|
*/
|
|
if ((error = buf_recycle(defrag)) != 0) {
|
|
atomic_set_int(&needsbuffer, 1);
|
|
bufspace_daemonwakeup();
|
|
error = buf_recycle(defrag);
|
|
}
|
|
if (error == 0)
|
|
atomic_add_int(&getnewbufrestarts, 1);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* bremfree:
|
|
*
|
|
* Mark the buffer for removal from the appropriate free list.
|
|
*
|
|
*/
|
|
void
|
|
bremfree(struct buf *bp)
|
|
{
|
|
|
|
CTR3(KTR_BUF, "bremfree(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
|
|
KASSERT((bp->b_flags & B_REMFREE) == 0,
|
|
("bremfree: buffer %p already marked for delayed removal.", bp));
|
|
KASSERT(bp->b_qindex != QUEUE_NONE,
|
|
("bremfree: buffer %p not on a queue.", bp));
|
|
BUF_ASSERT_XLOCKED(bp);
|
|
|
|
bp->b_flags |= B_REMFREE;
|
|
}
|
|
|
|
/*
|
|
* bremfreef:
|
|
*
|
|
* Force an immediate removal from a free list. Used only in nfs when
|
|
* it abuses the b_freelist pointer.
|
|
*/
|
|
void
|
|
bremfreef(struct buf *bp)
|
|
{
|
|
struct mtx *qlock;
|
|
|
|
qlock = bqlock(bp->b_qindex);
|
|
mtx_lock(qlock);
|
|
bremfreel(bp);
|
|
mtx_unlock(qlock);
|
|
}
|
|
|
|
/*
|
|
* bremfreel:
|
|
*
|
|
* Removes a buffer from the free list, must be called with the
|
|
* correct qlock held.
|
|
*/
|
|
static void
|
|
bremfreel(struct buf *bp)
|
|
{
|
|
|
|
CTR3(KTR_BUF, "bremfreel(%p) vp %p flags %X",
|
|
bp, bp->b_vp, bp->b_flags);
|
|
KASSERT(bp->b_qindex != QUEUE_NONE,
|
|
("bremfreel: buffer %p not on a queue.", bp));
|
|
if (bp->b_qindex != QUEUE_EMPTY) {
|
|
BUF_ASSERT_XLOCKED(bp);
|
|
}
|
|
mtx_assert(bqlock(bp->b_qindex), MA_OWNED);
|
|
|
|
TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist);
|
|
#ifdef INVARIANTS
|
|
KASSERT(bq_len[bp->b_qindex] >= 1, ("queue %d underflow",
|
|
bp->b_qindex));
|
|
bq_len[bp->b_qindex]--;
|
|
#endif
|
|
bp->b_qindex = QUEUE_NONE;
|
|
bp->b_flags &= ~B_REMFREE;
|
|
}
|
|
|
|
/*
|
|
* bufkva_free:
|
|
*
|
|
* Free the kva allocation for a buffer.
|
|
*
|
|
*/
|
|
static void
|
|
bufkva_free(struct buf *bp)
|
|
{
|
|
|
|
#ifdef INVARIANTS
|
|
if (bp->b_kvasize == 0) {
|
|
KASSERT(bp->b_kvabase == unmapped_buf &&
|
|
bp->b_data == unmapped_buf,
|
|
("Leaked KVA space on %p", bp));
|
|
} else if (buf_mapped(bp))
|
|
BUF_CHECK_MAPPED(bp);
|
|
else
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
#endif
|
|
if (bp->b_kvasize == 0)
|
|
return;
|
|
|
|
vmem_free(buffer_arena, (vm_offset_t)bp->b_kvabase, bp->b_kvasize);
|
|
atomic_subtract_long(&bufkvaspace, bp->b_kvasize);
|
|
atomic_add_int(&buffreekvacnt, 1);
|
|
bp->b_data = bp->b_kvabase = unmapped_buf;
|
|
bp->b_kvasize = 0;
|
|
}
|
|
|
|
/*
|
|
* bufkva_alloc:
|
|
*
|
|
* Allocate the buffer KVA and set b_kvasize and b_kvabase.
|
|
*/
|
|
static int
|
|
bufkva_alloc(struct buf *bp, int maxsize, int gbflags)
|
|
{
|
|
vm_offset_t addr;
|
|
int error;
|
|
|
|
KASSERT((gbflags & GB_UNMAPPED) == 0 || (gbflags & GB_KVAALLOC) != 0,
|
|
("Invalid gbflags 0x%x in %s", gbflags, __func__));
|
|
|
|
bufkva_free(bp);
|
|
|
|
addr = 0;
|
|
error = vmem_alloc(buffer_arena, maxsize, M_BESTFIT | M_NOWAIT, &addr);
|
|
if (error != 0) {
|
|
/*
|
|
* Buffer map is too fragmented. Request the caller
|
|
* to defragment the map.
|
|
*/
|
|
return (error);
|
|
}
|
|
bp->b_kvabase = (caddr_t)addr;
|
|
bp->b_kvasize = maxsize;
|
|
atomic_add_long(&bufkvaspace, bp->b_kvasize);
|
|
if ((gbflags & GB_UNMAPPED) != 0) {
|
|
bp->b_data = unmapped_buf;
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
} else {
|
|
bp->b_data = bp->b_kvabase;
|
|
BUF_CHECK_MAPPED(bp);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* bufkva_reclaim:
|
|
*
|
|
* Reclaim buffer kva by freeing buffers holding kva. This is a vmem
|
|
* callback that fires to avoid returning failure.
|
|
*/
|
|
static void
|
|
bufkva_reclaim(vmem_t *vmem, int flags)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 5; i++)
|
|
if (buf_scan(true) != 0)
|
|
break;
|
|
return;
|
|
}
|
|
|
|
|
|
/*
|
|
* Attempt to initiate asynchronous I/O on read-ahead blocks. We must
|
|
* clear BIO_ERROR and B_INVAL prior to initiating I/O . If B_CACHE is set,
|
|
* the buffer is valid and we do not have to do anything.
|
|
*/
|
|
void
|
|
breada(struct vnode * vp, daddr_t * rablkno, int * rabsize,
|
|
int cnt, struct ucred * cred)
|
|
{
|
|
struct buf *rabp;
|
|
int i;
|
|
|
|
for (i = 0; i < cnt; i++, rablkno++, rabsize++) {
|
|
if (inmem(vp, *rablkno))
|
|
continue;
|
|
rabp = getblk(vp, *rablkno, *rabsize, 0, 0, 0);
|
|
|
|
if ((rabp->b_flags & B_CACHE) == 0) {
|
|
if (!TD_IS_IDLETHREAD(curthread)) {
|
|
#ifdef RACCT
|
|
if (racct_enable) {
|
|
PROC_LOCK(curproc);
|
|
racct_add_buf(curproc, rabp, 0);
|
|
PROC_UNLOCK(curproc);
|
|
}
|
|
#endif /* RACCT */
|
|
curthread->td_ru.ru_inblock++;
|
|
}
|
|
rabp->b_flags |= B_ASYNC;
|
|
rabp->b_flags &= ~B_INVAL;
|
|
rabp->b_ioflags &= ~BIO_ERROR;
|
|
rabp->b_iocmd = BIO_READ;
|
|
if (rabp->b_rcred == NOCRED && cred != NOCRED)
|
|
rabp->b_rcred = crhold(cred);
|
|
vfs_busy_pages(rabp, 0);
|
|
BUF_KERNPROC(rabp);
|
|
rabp->b_iooffset = dbtob(rabp->b_blkno);
|
|
bstrategy(rabp);
|
|
} else {
|
|
brelse(rabp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Entry point for bread() and breadn() via #defines in sys/buf.h.
|
|
*
|
|
* Get a buffer with the specified data. Look in the cache first. We
|
|
* must clear BIO_ERROR and B_INVAL prior to initiating I/O. If B_CACHE
|
|
* is set, the buffer is valid and we do not have to do anything, see
|
|
* getblk(). Also starts asynchronous I/O on read-ahead blocks.
|
|
*
|
|
* Always return a NULL buffer pointer (in bpp) when returning an error.
|
|
*/
|
|
int
|
|
breadn_flags(struct vnode *vp, daddr_t blkno, int size, daddr_t *rablkno,
|
|
int *rabsize, int cnt, struct ucred *cred, int flags, struct buf **bpp)
|
|
{
|
|
struct buf *bp;
|
|
int rv = 0, readwait = 0;
|
|
|
|
CTR3(KTR_BUF, "breadn(%p, %jd, %d)", vp, blkno, size);
|
|
/*
|
|
* Can only return NULL if GB_LOCK_NOWAIT flag is specified.
|
|
*/
|
|
*bpp = bp = getblk(vp, blkno, size, 0, 0, flags);
|
|
if (bp == NULL)
|
|
return (EBUSY);
|
|
|
|
/* if not found in cache, do some I/O */
|
|
if ((bp->b_flags & B_CACHE) == 0) {
|
|
if (!TD_IS_IDLETHREAD(curthread)) {
|
|
#ifdef RACCT
|
|
if (racct_enable) {
|
|
PROC_LOCK(curproc);
|
|
racct_add_buf(curproc, bp, 0);
|
|
PROC_UNLOCK(curproc);
|
|
}
|
|
#endif /* RACCT */
|
|
curthread->td_ru.ru_inblock++;
|
|
}
|
|
bp->b_iocmd = BIO_READ;
|
|
bp->b_flags &= ~B_INVAL;
|
|
bp->b_ioflags &= ~BIO_ERROR;
|
|
if (bp->b_rcred == NOCRED && cred != NOCRED)
|
|
bp->b_rcred = crhold(cred);
|
|
vfs_busy_pages(bp, 0);
|
|
bp->b_iooffset = dbtob(bp->b_blkno);
|
|
bstrategy(bp);
|
|
++readwait;
|
|
}
|
|
|
|
breada(vp, rablkno, rabsize, cnt, cred);
|
|
|
|
if (readwait) {
|
|
rv = bufwait(bp);
|
|
if (rv != 0) {
|
|
brelse(bp);
|
|
*bpp = NULL;
|
|
}
|
|
}
|
|
return (rv);
|
|
}
|
|
|
|
/*
|
|
* Write, release buffer on completion. (Done by iodone
|
|
* if async). Do not bother writing anything if the buffer
|
|
* is invalid.
|
|
*
|
|
* Note that we set B_CACHE here, indicating that buffer is
|
|
* fully valid and thus cacheable. This is true even of NFS
|
|
* now so we set it generally. This could be set either here
|
|
* or in biodone() since the I/O is synchronous. We put it
|
|
* here.
|
|
*/
|
|
int
|
|
bufwrite(struct buf *bp)
|
|
{
|
|
int oldflags;
|
|
struct vnode *vp;
|
|
long space;
|
|
int vp_md;
|
|
|
|
CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
|
|
if ((bp->b_bufobj->bo_flag & BO_DEAD) != 0) {
|
|
bp->b_flags |= B_INVAL | B_RELBUF;
|
|
bp->b_flags &= ~B_CACHE;
|
|
brelse(bp);
|
|
return (ENXIO);
|
|
}
|
|
if (bp->b_flags & B_INVAL) {
|
|
brelse(bp);
|
|
return (0);
|
|
}
|
|
|
|
if (bp->b_flags & B_BARRIER)
|
|
barrierwrites++;
|
|
|
|
oldflags = bp->b_flags;
|
|
|
|
BUF_ASSERT_HELD(bp);
|
|
|
|
KASSERT(!(bp->b_vflags & BV_BKGRDINPROG),
|
|
("FFS background buffer should not get here %p", bp));
|
|
|
|
vp = bp->b_vp;
|
|
if (vp)
|
|
vp_md = vp->v_vflag & VV_MD;
|
|
else
|
|
vp_md = 0;
|
|
|
|
/*
|
|
* Mark the buffer clean. Increment the bufobj write count
|
|
* before bundirty() call, to prevent other thread from seeing
|
|
* empty dirty list and zero counter for writes in progress,
|
|
* falsely indicating that the bufobj is clean.
|
|
*/
|
|
bufobj_wref(bp->b_bufobj);
|
|
bundirty(bp);
|
|
|
|
bp->b_flags &= ~B_DONE;
|
|
bp->b_ioflags &= ~BIO_ERROR;
|
|
bp->b_flags |= B_CACHE;
|
|
bp->b_iocmd = BIO_WRITE;
|
|
|
|
vfs_busy_pages(bp, 1);
|
|
|
|
/*
|
|
* Normal bwrites pipeline writes
|
|
*/
|
|
bp->b_runningbufspace = bp->b_bufsize;
|
|
space = atomic_fetchadd_long(&runningbufspace, bp->b_runningbufspace);
|
|
|
|
if (!TD_IS_IDLETHREAD(curthread)) {
|
|
#ifdef RACCT
|
|
if (racct_enable) {
|
|
PROC_LOCK(curproc);
|
|
racct_add_buf(curproc, bp, 1);
|
|
PROC_UNLOCK(curproc);
|
|
}
|
|
#endif /* RACCT */
|
|
curthread->td_ru.ru_oublock++;
|
|
}
|
|
if (oldflags & B_ASYNC)
|
|
BUF_KERNPROC(bp);
|
|
bp->b_iooffset = dbtob(bp->b_blkno);
|
|
bstrategy(bp);
|
|
|
|
if ((oldflags & B_ASYNC) == 0) {
|
|
int rtval = bufwait(bp);
|
|
brelse(bp);
|
|
return (rtval);
|
|
} else if (space > hirunningspace) {
|
|
/*
|
|
* don't allow the async write to saturate the I/O
|
|
* system. We will not deadlock here because
|
|
* we are blocking waiting for I/O that is already in-progress
|
|
* to complete. We do not block here if it is the update
|
|
* or syncer daemon trying to clean up as that can lead
|
|
* to deadlock.
|
|
*/
|
|
if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md)
|
|
waitrunningbufspace();
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
bufbdflush(struct bufobj *bo, struct buf *bp)
|
|
{
|
|
struct buf *nbp;
|
|
|
|
if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10) {
|
|
(void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread);
|
|
altbufferflushes++;
|
|
} else if (bo->bo_dirty.bv_cnt > dirtybufthresh) {
|
|
BO_LOCK(bo);
|
|
/*
|
|
* Try to find a buffer to flush.
|
|
*/
|
|
TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) {
|
|
if ((nbp->b_vflags & BV_BKGRDINPROG) ||
|
|
BUF_LOCK(nbp,
|
|
LK_EXCLUSIVE | LK_NOWAIT, NULL))
|
|
continue;
|
|
if (bp == nbp)
|
|
panic("bdwrite: found ourselves");
|
|
BO_UNLOCK(bo);
|
|
/* Don't countdeps with the bo lock held. */
|
|
if (buf_countdeps(nbp, 0)) {
|
|
BO_LOCK(bo);
|
|
BUF_UNLOCK(nbp);
|
|
continue;
|
|
}
|
|
if (nbp->b_flags & B_CLUSTEROK) {
|
|
vfs_bio_awrite(nbp);
|
|
} else {
|
|
bremfree(nbp);
|
|
bawrite(nbp);
|
|
}
|
|
dirtybufferflushes++;
|
|
break;
|
|
}
|
|
if (nbp == NULL)
|
|
BO_UNLOCK(bo);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Delayed write. (Buffer is marked dirty). Do not bother writing
|
|
* anything if the buffer is marked invalid.
|
|
*
|
|
* Note that since the buffer must be completely valid, we can safely
|
|
* set B_CACHE. In fact, we have to set B_CACHE here rather then in
|
|
* biodone() in order to prevent getblk from writing the buffer
|
|
* out synchronously.
|
|
*/
|
|
void
|
|
bdwrite(struct buf *bp)
|
|
{
|
|
struct thread *td = curthread;
|
|
struct vnode *vp;
|
|
struct bufobj *bo;
|
|
|
|
CTR3(KTR_BUF, "bdwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
|
|
KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
|
|
KASSERT((bp->b_flags & B_BARRIER) == 0,
|
|
("Barrier request in delayed write %p", bp));
|
|
BUF_ASSERT_HELD(bp);
|
|
|
|
if (bp->b_flags & B_INVAL) {
|
|
brelse(bp);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If we have too many dirty buffers, don't create any more.
|
|
* If we are wildly over our limit, then force a complete
|
|
* cleanup. Otherwise, just keep the situation from getting
|
|
* out of control. Note that we have to avoid a recursive
|
|
* disaster and not try to clean up after our own cleanup!
|
|
*/
|
|
vp = bp->b_vp;
|
|
bo = bp->b_bufobj;
|
|
if ((td->td_pflags & (TDP_COWINPROGRESS|TDP_INBDFLUSH)) == 0) {
|
|
td->td_pflags |= TDP_INBDFLUSH;
|
|
BO_BDFLUSH(bo, bp);
|
|
td->td_pflags &= ~TDP_INBDFLUSH;
|
|
} else
|
|
recursiveflushes++;
|
|
|
|
bdirty(bp);
|
|
/*
|
|
* Set B_CACHE, indicating that the buffer is fully valid. This is
|
|
* true even of NFS now.
|
|
*/
|
|
bp->b_flags |= B_CACHE;
|
|
|
|
/*
|
|
* This bmap keeps the system from needing to do the bmap later,
|
|
* perhaps when the system is attempting to do a sync. Since it
|
|
* is likely that the indirect block -- or whatever other datastructure
|
|
* that the filesystem needs is still in memory now, it is a good
|
|
* thing to do this. Note also, that if the pageout daemon is
|
|
* requesting a sync -- there might not be enough memory to do
|
|
* the bmap then... So, this is important to do.
|
|
*/
|
|
if (vp->v_type != VCHR && bp->b_lblkno == bp->b_blkno) {
|
|
VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL);
|
|
}
|
|
|
|
/*
|
|
* Set the *dirty* buffer range based upon the VM system dirty
|
|
* pages.
|
|
*
|
|
* Mark the buffer pages as clean. We need to do this here to
|
|
* satisfy the vnode_pager and the pageout daemon, so that it
|
|
* thinks that the pages have been "cleaned". Note that since
|
|
* the pages are in a delayed write buffer -- the VFS layer
|
|
* "will" see that the pages get written out on the next sync,
|
|
* or perhaps the cluster will be completed.
|
|
*/
|
|
vfs_clean_pages_dirty_buf(bp);
|
|
bqrelse(bp);
|
|
|
|
/*
|
|
* note: we cannot initiate I/O from a bdwrite even if we wanted to,
|
|
* due to the softdep code.
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* bdirty:
|
|
*
|
|
* Turn buffer into delayed write request. We must clear BIO_READ and
|
|
* B_RELBUF, and we must set B_DELWRI. We reassign the buffer to
|
|
* itself to properly update it in the dirty/clean lists. We mark it
|
|
* B_DONE to ensure that any asynchronization of the buffer properly
|
|
* clears B_DONE ( else a panic will occur later ).
|
|
*
|
|
* bdirty() is kinda like bdwrite() - we have to clear B_INVAL which
|
|
* might have been set pre-getblk(). Unlike bwrite/bdwrite, bdirty()
|
|
* should only be called if the buffer is known-good.
|
|
*
|
|
* Since the buffer is not on a queue, we do not update the numfreebuffers
|
|
* count.
|
|
*
|
|
* The buffer must be on QUEUE_NONE.
|
|
*/
|
|
void
|
|
bdirty(struct buf *bp)
|
|
{
|
|
|
|
CTR3(KTR_BUF, "bdirty(%p) vp %p flags %X",
|
|
bp, bp->b_vp, bp->b_flags);
|
|
KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
|
|
KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE,
|
|
("bdirty: buffer %p still on queue %d", bp, bp->b_qindex));
|
|
BUF_ASSERT_HELD(bp);
|
|
bp->b_flags &= ~(B_RELBUF);
|
|
bp->b_iocmd = BIO_WRITE;
|
|
|
|
if ((bp->b_flags & B_DELWRI) == 0) {
|
|
bp->b_flags |= /* XXX B_DONE | */ B_DELWRI;
|
|
reassignbuf(bp);
|
|
bdirtyadd();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* bundirty:
|
|
*
|
|
* Clear B_DELWRI for buffer.
|
|
*
|
|
* Since the buffer is not on a queue, we do not update the numfreebuffers
|
|
* count.
|
|
*
|
|
* The buffer must be on QUEUE_NONE.
|
|
*/
|
|
|
|
void
|
|
bundirty(struct buf *bp)
|
|
{
|
|
|
|
CTR3(KTR_BUF, "bundirty(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
|
|
KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
|
|
KASSERT(bp->b_flags & B_REMFREE || bp->b_qindex == QUEUE_NONE,
|
|
("bundirty: buffer %p still on queue %d", bp, bp->b_qindex));
|
|
BUF_ASSERT_HELD(bp);
|
|
|
|
if (bp->b_flags & B_DELWRI) {
|
|
bp->b_flags &= ~B_DELWRI;
|
|
reassignbuf(bp);
|
|
bdirtysub();
|
|
}
|
|
/*
|
|
* Since it is now being written, we can clear its deferred write flag.
|
|
*/
|
|
bp->b_flags &= ~B_DEFERRED;
|
|
}
|
|
|
|
/*
|
|
* bawrite:
|
|
*
|
|
* Asynchronous write. Start output on a buffer, but do not wait for
|
|
* it to complete. The buffer is released when the output completes.
|
|
*
|
|
* bwrite() ( or the VOP routine anyway ) is responsible for handling
|
|
* B_INVAL buffers. Not us.
|
|
*/
|
|
void
|
|
bawrite(struct buf *bp)
|
|
{
|
|
|
|
bp->b_flags |= B_ASYNC;
|
|
(void) bwrite(bp);
|
|
}
|
|
|
|
/*
|
|
* babarrierwrite:
|
|
*
|
|
* Asynchronous barrier write. Start output on a buffer, but do not
|
|
* wait for it to complete. Place a write barrier after this write so
|
|
* that this buffer and all buffers written before it are committed to
|
|
* the disk before any buffers written after this write are committed
|
|
* to the disk. The buffer is released when the output completes.
|
|
*/
|
|
void
|
|
babarrierwrite(struct buf *bp)
|
|
{
|
|
|
|
bp->b_flags |= B_ASYNC | B_BARRIER;
|
|
(void) bwrite(bp);
|
|
}
|
|
|
|
/*
|
|
* bbarrierwrite:
|
|
*
|
|
* Synchronous barrier write. Start output on a buffer and wait for
|
|
* it to complete. Place a write barrier after this write so that
|
|
* this buffer and all buffers written before it are committed to
|
|
* the disk before any buffers written after this write are committed
|
|
* to the disk. The buffer is released when the output completes.
|
|
*/
|
|
int
|
|
bbarrierwrite(struct buf *bp)
|
|
{
|
|
|
|
bp->b_flags |= B_BARRIER;
|
|
return (bwrite(bp));
|
|
}
|
|
|
|
/*
|
|
* bwillwrite:
|
|
*
|
|
* Called prior to the locking of any vnodes when we are expecting to
|
|
* write. We do not want to starve the buffer cache with too many
|
|
* dirty buffers so we block here. By blocking prior to the locking
|
|
* of any vnodes we attempt to avoid the situation where a locked vnode
|
|
* prevents the various system daemons from flushing related buffers.
|
|
*/
|
|
void
|
|
bwillwrite(void)
|
|
{
|
|
|
|
if (numdirtybuffers >= hidirtybuffers) {
|
|
mtx_lock(&bdirtylock);
|
|
while (numdirtybuffers >= hidirtybuffers) {
|
|
bdirtywait = 1;
|
|
msleep(&bdirtywait, &bdirtylock, (PRIBIO + 4),
|
|
"flswai", 0);
|
|
}
|
|
mtx_unlock(&bdirtylock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return true if we have too many dirty buffers.
|
|
*/
|
|
int
|
|
buf_dirty_count_severe(void)
|
|
{
|
|
|
|
return(numdirtybuffers >= hidirtybuffers);
|
|
}
|
|
|
|
/*
|
|
* brelse:
|
|
*
|
|
* Release a busy buffer and, if requested, free its resources. The
|
|
* buffer will be stashed in the appropriate bufqueue[] allowing it
|
|
* to be accessed later as a cache entity or reused for other purposes.
|
|
*/
|
|
void
|
|
brelse(struct buf *bp)
|
|
{
|
|
int qindex;
|
|
|
|
/*
|
|
* Many functions erroneously call brelse with a NULL bp under rare
|
|
* error conditions. Simply return when called with a NULL bp.
|
|
*/
|
|
if (bp == NULL)
|
|
return;
|
|
CTR3(KTR_BUF, "brelse(%p) vp %p flags %X",
|
|
bp, bp->b_vp, bp->b_flags);
|
|
KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)),
|
|
("brelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp));
|
|
KASSERT((bp->b_flags & B_VMIO) != 0 || (bp->b_flags & B_NOREUSE) == 0,
|
|
("brelse: non-VMIO buffer marked NOREUSE"));
|
|
|
|
if (BUF_LOCKRECURSED(bp)) {
|
|
/*
|
|
* Do not process, in particular, do not handle the
|
|
* B_INVAL/B_RELBUF and do not release to free list.
|
|
*/
|
|
BUF_UNLOCK(bp);
|
|
return;
|
|
}
|
|
|
|
if (bp->b_flags & B_MANAGED) {
|
|
bqrelse(bp);
|
|
return;
|
|
}
|
|
|
|
if ((bp->b_vflags & (BV_BKGRDINPROG | BV_BKGRDERR)) == BV_BKGRDERR) {
|
|
BO_LOCK(bp->b_bufobj);
|
|
bp->b_vflags &= ~BV_BKGRDERR;
|
|
BO_UNLOCK(bp->b_bufobj);
|
|
bdirty(bp);
|
|
}
|
|
if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) &&
|
|
!(bp->b_flags & B_INVAL)) {
|
|
/*
|
|
* Failed write, redirty. Must clear BIO_ERROR to prevent
|
|
* pages from being scrapped.
|
|
*/
|
|
bp->b_ioflags &= ~BIO_ERROR;
|
|
bdirty(bp);
|
|
} else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) ||
|
|
(bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) {
|
|
/*
|
|
* Either a failed read I/O or we were asked to free or not
|
|
* cache the buffer.
|
|
*/
|
|
bp->b_flags |= B_INVAL;
|
|
if (!LIST_EMPTY(&bp->b_dep))
|
|
buf_deallocate(bp);
|
|
if (bp->b_flags & B_DELWRI)
|
|
bdirtysub();
|
|
bp->b_flags &= ~(B_DELWRI | B_CACHE);
|
|
if ((bp->b_flags & B_VMIO) == 0) {
|
|
allocbuf(bp, 0);
|
|
if (bp->b_vp)
|
|
brelvp(bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_truncate()
|
|
* is called with B_DELWRI set, the underlying pages may wind up
|
|
* getting freed causing a previous write (bdwrite()) to get 'lost'
|
|
* because pages associated with a B_DELWRI bp are marked clean.
|
|
*
|
|
* We still allow the B_INVAL case to call vfs_vmio_truncate(), even
|
|
* if B_DELWRI is set.
|
|
*/
|
|
if (bp->b_flags & B_DELWRI)
|
|
bp->b_flags &= ~B_RELBUF;
|
|
|
|
/*
|
|
* VMIO buffer rundown. It is not very necessary to keep a VMIO buffer
|
|
* constituted, not even NFS buffers now. Two flags effect this. If
|
|
* B_INVAL, the struct buf is invalidated but the VM object is kept
|
|
* around ( i.e. so it is trivial to reconstitute the buffer later ).
|
|
*
|
|
* If BIO_ERROR or B_NOCACHE is set, pages in the VM object will be
|
|
* invalidated. BIO_ERROR cannot be set for a failed write unless the
|
|
* buffer is also B_INVAL because it hits the re-dirtying code above.
|
|
*
|
|
* Normally we can do this whether a buffer is B_DELWRI or not. If
|
|
* the buffer is an NFS buffer, it is tracking piecemeal writes or
|
|
* the commit state and we cannot afford to lose the buffer. If the
|
|
* buffer has a background write in progress, we need to keep it
|
|
* around to prevent it from being reconstituted and starting a second
|
|
* background write.
|
|
*/
|
|
if ((bp->b_flags & B_VMIO) && (bp->b_flags & B_NOCACHE ||
|
|
(bp->b_ioflags & BIO_ERROR && bp->b_iocmd == BIO_READ)) &&
|
|
!(bp->b_vp->v_mount != NULL &&
|
|
(bp->b_vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
|
|
!vn_isdisk(bp->b_vp, NULL) && (bp->b_flags & B_DELWRI))) {
|
|
vfs_vmio_invalidate(bp);
|
|
allocbuf(bp, 0);
|
|
}
|
|
|
|
if ((bp->b_flags & (B_INVAL | B_RELBUF)) != 0 ||
|
|
(bp->b_flags & (B_DELWRI | B_NOREUSE)) == B_NOREUSE) {
|
|
allocbuf(bp, 0);
|
|
bp->b_flags &= ~B_NOREUSE;
|
|
if (bp->b_vp != NULL)
|
|
brelvp(bp);
|
|
}
|
|
|
|
/*
|
|
* If the buffer has junk contents signal it and eventually
|
|
* clean up B_DELWRI and diassociate the vnode so that gbincore()
|
|
* doesn't find it.
|
|
*/
|
|
if (bp->b_bufsize == 0 || (bp->b_ioflags & BIO_ERROR) != 0 ||
|
|
(bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF)) != 0)
|
|
bp->b_flags |= B_INVAL;
|
|
if (bp->b_flags & B_INVAL) {
|
|
if (bp->b_flags & B_DELWRI)
|
|
bundirty(bp);
|
|
if (bp->b_vp)
|
|
brelvp(bp);
|
|
}
|
|
|
|
/* buffers with no memory */
|
|
if (bp->b_bufsize == 0) {
|
|
buf_free(bp);
|
|
return;
|
|
}
|
|
/* buffers with junk contents */
|
|
if (bp->b_flags & (B_INVAL | B_NOCACHE | B_RELBUF) ||
|
|
(bp->b_ioflags & BIO_ERROR)) {
|
|
bp->b_xflags &= ~(BX_BKGRDWRITE | BX_ALTDATA);
|
|
if (bp->b_vflags & BV_BKGRDINPROG)
|
|
panic("losing buffer 2");
|
|
qindex = QUEUE_CLEAN;
|
|
bp->b_flags |= B_AGE;
|
|
/* remaining buffers */
|
|
} else if (bp->b_flags & B_DELWRI)
|
|
qindex = QUEUE_DIRTY;
|
|
else
|
|
qindex = QUEUE_CLEAN;
|
|
|
|
binsfree(bp, qindex);
|
|
|
|
bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF | B_DIRECT);
|
|
if ((bp->b_flags & B_DELWRI) == 0 && (bp->b_xflags & BX_VNDIRTY))
|
|
panic("brelse: not dirty");
|
|
/* unlock */
|
|
BUF_UNLOCK(bp);
|
|
if (qindex == QUEUE_CLEAN)
|
|
bufspace_wakeup();
|
|
}
|
|
|
|
/*
|
|
* Release a buffer back to the appropriate queue but do not try to free
|
|
* it. The buffer is expected to be used again soon.
|
|
*
|
|
* bqrelse() is used by bdwrite() to requeue a delayed write, and used by
|
|
* biodone() to requeue an async I/O on completion. It is also used when
|
|
* known good buffers need to be requeued but we think we may need the data
|
|
* again soon.
|
|
*
|
|
* XXX we should be able to leave the B_RELBUF hint set on completion.
|
|
*/
|
|
void
|
|
bqrelse(struct buf *bp)
|
|
{
|
|
int qindex;
|
|
|
|
CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
|
|
KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)),
|
|
("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp));
|
|
|
|
qindex = QUEUE_NONE;
|
|
if (BUF_LOCKRECURSED(bp)) {
|
|
/* do not release to free list */
|
|
BUF_UNLOCK(bp);
|
|
return;
|
|
}
|
|
bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF);
|
|
|
|
if (bp->b_flags & B_MANAGED) {
|
|
if (bp->b_flags & B_REMFREE)
|
|
bremfreef(bp);
|
|
goto out;
|
|
}
|
|
|
|
/* buffers with stale but valid contents */
|
|
if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG |
|
|
BV_BKGRDERR)) == BV_BKGRDERR) {
|
|
BO_LOCK(bp->b_bufobj);
|
|
bp->b_vflags &= ~BV_BKGRDERR;
|
|
BO_UNLOCK(bp->b_bufobj);
|
|
qindex = QUEUE_DIRTY;
|
|
} else {
|
|
if ((bp->b_flags & B_DELWRI) == 0 &&
|
|
(bp->b_xflags & BX_VNDIRTY))
|
|
panic("bqrelse: not dirty");
|
|
if ((bp->b_flags & B_NOREUSE) != 0) {
|
|
brelse(bp);
|
|
return;
|
|
}
|
|
qindex = QUEUE_CLEAN;
|
|
}
|
|
binsfree(bp, qindex);
|
|
|
|
out:
|
|
/* unlock */
|
|
BUF_UNLOCK(bp);
|
|
if (qindex == QUEUE_CLEAN)
|
|
bufspace_wakeup();
|
|
}
|
|
|
|
/*
|
|
* Complete I/O to a VMIO backed page. Validate the pages as appropriate,
|
|
* restore bogus pages.
|
|
*/
|
|
static void
|
|
vfs_vmio_iodone(struct buf *bp)
|
|
{
|
|
vm_ooffset_t foff;
|
|
vm_page_t m;
|
|
vm_object_t obj;
|
|
struct vnode *vp;
|
|
int bogus, i, iosize;
|
|
|
|
obj = bp->b_bufobj->bo_object;
|
|
KASSERT(obj->paging_in_progress >= bp->b_npages,
|
|
("vfs_vmio_iodone: paging in progress(%d) < b_npages(%d)",
|
|
obj->paging_in_progress, bp->b_npages));
|
|
|
|
vp = bp->b_vp;
|
|
KASSERT(vp->v_holdcnt > 0,
|
|
("vfs_vmio_iodone: vnode %p has zero hold count", vp));
|
|
KASSERT(vp->v_object != NULL,
|
|
("vfs_vmio_iodone: vnode %p has no vm_object", vp));
|
|
|
|
foff = bp->b_offset;
|
|
KASSERT(bp->b_offset != NOOFFSET,
|
|
("vfs_vmio_iodone: bp %p has no buffer offset", bp));
|
|
|
|
bogus = 0;
|
|
iosize = bp->b_bcount - bp->b_resid;
|
|
VM_OBJECT_WLOCK(obj);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
int resid;
|
|
|
|
resid = ((foff + PAGE_SIZE) & ~(off_t)PAGE_MASK) - foff;
|
|
if (resid > iosize)
|
|
resid = iosize;
|
|
|
|
/*
|
|
* cleanup bogus pages, restoring the originals
|
|
*/
|
|
m = bp->b_pages[i];
|
|
if (m == bogus_page) {
|
|
bogus = 1;
|
|
m = vm_page_lookup(obj, OFF_TO_IDX(foff));
|
|
if (m == NULL)
|
|
panic("biodone: page disappeared!");
|
|
bp->b_pages[i] = m;
|
|
} else if ((bp->b_iocmd == BIO_READ) && resid > 0) {
|
|
/*
|
|
* In the write case, the valid and clean bits are
|
|
* already changed correctly ( see bdwrite() ), so we
|
|
* only need to do this here in the read case.
|
|
*/
|
|
KASSERT((m->dirty & vm_page_bits(foff & PAGE_MASK,
|
|
resid)) == 0, ("vfs_vmio_iodone: page %p "
|
|
"has unexpected dirty bits", m));
|
|
vfs_page_set_valid(bp, foff, m);
|
|
}
|
|
KASSERT(OFF_TO_IDX(foff) == m->pindex,
|
|
("vfs_vmio_iodone: foff(%jd)/pindex(%ju) mismatch",
|
|
(intmax_t)foff, (uintmax_t)m->pindex));
|
|
|
|
vm_page_sunbusy(m);
|
|
foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
|
|
iosize -= resid;
|
|
}
|
|
vm_object_pip_wakeupn(obj, bp->b_npages);
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
if (bogus && buf_mapped(bp)) {
|
|
BUF_CHECK_MAPPED(bp);
|
|
pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
|
|
bp->b_pages, bp->b_npages);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Unwire a page held by a buf and place it on the appropriate vm queue.
|
|
*/
|
|
static void
|
|
vfs_vmio_unwire(struct buf *bp, vm_page_t m)
|
|
{
|
|
bool freed;
|
|
|
|
vm_page_lock(m);
|
|
if (vm_page_unwire(m, PQ_NONE)) {
|
|
/*
|
|
* Determine if the page should be freed before adding
|
|
* it to the inactive queue.
|
|
*/
|
|
if (m->valid == 0) {
|
|
freed = !vm_page_busied(m);
|
|
if (freed)
|
|
vm_page_free(m);
|
|
} else if ((bp->b_flags & B_DIRECT) != 0)
|
|
freed = vm_page_try_to_free(m);
|
|
else
|
|
freed = false;
|
|
if (!freed) {
|
|
/*
|
|
* If the page is unlikely to be reused, let the
|
|
* VM know. Otherwise, maintain LRU page
|
|
* ordering and put the page at the tail of the
|
|
* inactive queue.
|
|
*/
|
|
if ((bp->b_flags & B_NOREUSE) != 0)
|
|
vm_page_deactivate_noreuse(m);
|
|
else
|
|
vm_page_deactivate(m);
|
|
}
|
|
}
|
|
vm_page_unlock(m);
|
|
}
|
|
|
|
/*
|
|
* Perform page invalidation when a buffer is released. The fully invalid
|
|
* pages will be reclaimed later in vfs_vmio_truncate().
|
|
*/
|
|
static void
|
|
vfs_vmio_invalidate(struct buf *bp)
|
|
{
|
|
vm_object_t obj;
|
|
vm_page_t m;
|
|
int i, resid, poffset, presid;
|
|
|
|
if (buf_mapped(bp)) {
|
|
BUF_CHECK_MAPPED(bp);
|
|
pmap_qremove(trunc_page((vm_offset_t)bp->b_data), bp->b_npages);
|
|
} else
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
/*
|
|
* Get the base offset and length of the buffer. Note that
|
|
* in the VMIO case if the buffer block size is not
|
|
* page-aligned then b_data pointer may not be page-aligned.
|
|
* But our b_pages[] array *IS* page aligned.
|
|
*
|
|
* block sizes less then DEV_BSIZE (usually 512) are not
|
|
* supported due to the page granularity bits (m->valid,
|
|
* m->dirty, etc...).
|
|
*
|
|
* See man buf(9) for more information
|
|
*/
|
|
obj = bp->b_bufobj->bo_object;
|
|
resid = bp->b_bufsize;
|
|
poffset = bp->b_offset & PAGE_MASK;
|
|
VM_OBJECT_WLOCK(obj);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
if (m == bogus_page)
|
|
panic("vfs_vmio_invalidate: Unexpected bogus page.");
|
|
bp->b_pages[i] = NULL;
|
|
|
|
presid = resid > (PAGE_SIZE - poffset) ?
|
|
(PAGE_SIZE - poffset) : resid;
|
|
KASSERT(presid >= 0, ("brelse: extra page"));
|
|
while (vm_page_xbusied(m)) {
|
|
vm_page_lock(m);
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
vm_page_busy_sleep(m, "mbncsh");
|
|
VM_OBJECT_WLOCK(obj);
|
|
}
|
|
if (pmap_page_wired_mappings(m) == 0)
|
|
vm_page_set_invalid(m, poffset, presid);
|
|
vfs_vmio_unwire(bp, m);
|
|
resid -= presid;
|
|
poffset = 0;
|
|
}
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
bp->b_npages = 0;
|
|
}
|
|
|
|
/*
|
|
* Page-granular truncation of an existing VMIO buffer.
|
|
*/
|
|
static void
|
|
vfs_vmio_truncate(struct buf *bp, int desiredpages)
|
|
{
|
|
vm_object_t obj;
|
|
vm_page_t m;
|
|
int i;
|
|
|
|
if (bp->b_npages == desiredpages)
|
|
return;
|
|
|
|
if (buf_mapped(bp)) {
|
|
BUF_CHECK_MAPPED(bp);
|
|
pmap_qremove((vm_offset_t)trunc_page((vm_offset_t)bp->b_data) +
|
|
(desiredpages << PAGE_SHIFT), bp->b_npages - desiredpages);
|
|
} else
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
obj = bp->b_bufobj->bo_object;
|
|
if (obj != NULL)
|
|
VM_OBJECT_WLOCK(obj);
|
|
for (i = desiredpages; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
KASSERT(m != bogus_page, ("allocbuf: bogus page found"));
|
|
bp->b_pages[i] = NULL;
|
|
vfs_vmio_unwire(bp, m);
|
|
}
|
|
if (obj != NULL)
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
bp->b_npages = desiredpages;
|
|
}
|
|
|
|
/*
|
|
* Byte granular extension of VMIO buffers.
|
|
*/
|
|
static void
|
|
vfs_vmio_extend(struct buf *bp, int desiredpages, int size)
|
|
{
|
|
/*
|
|
* We are growing the buffer, possibly in a
|
|
* byte-granular fashion.
|
|
*/
|
|
vm_object_t obj;
|
|
vm_offset_t toff;
|
|
vm_offset_t tinc;
|
|
vm_page_t m;
|
|
|
|
/*
|
|
* Step 1, bring in the VM pages from the object, allocating
|
|
* them if necessary. We must clear B_CACHE if these pages
|
|
* are not valid for the range covered by the buffer.
|
|
*/
|
|
obj = bp->b_bufobj->bo_object;
|
|
VM_OBJECT_WLOCK(obj);
|
|
while (bp->b_npages < desiredpages) {
|
|
/*
|
|
* We must allocate system pages since blocking
|
|
* here could interfere with paging I/O, no
|
|
* matter which process we are.
|
|
*
|
|
* Only exclusive busy can be tested here.
|
|
* Blocking on shared busy might lead to
|
|
* deadlocks once allocbuf() is called after
|
|
* pages are vfs_busy_pages().
|
|
*/
|
|
m = vm_page_grab(obj, OFF_TO_IDX(bp->b_offset) + bp->b_npages,
|
|
VM_ALLOC_NOBUSY | VM_ALLOC_SYSTEM |
|
|
VM_ALLOC_WIRED | VM_ALLOC_IGN_SBUSY |
|
|
VM_ALLOC_COUNT(desiredpages - bp->b_npages));
|
|
if (m->valid == 0)
|
|
bp->b_flags &= ~B_CACHE;
|
|
bp->b_pages[bp->b_npages] = m;
|
|
++bp->b_npages;
|
|
}
|
|
|
|
/*
|
|
* Step 2. We've loaded the pages into the buffer,
|
|
* we have to figure out if we can still have B_CACHE
|
|
* set. Note that B_CACHE is set according to the
|
|
* byte-granular range ( bcount and size ), not the
|
|
* aligned range ( newbsize ).
|
|
*
|
|
* The VM test is against m->valid, which is DEV_BSIZE
|
|
* aligned. Needless to say, the validity of the data
|
|
* needs to also be DEV_BSIZE aligned. Note that this
|
|
* fails with NFS if the server or some other client
|
|
* extends the file's EOF. If our buffer is resized,
|
|
* B_CACHE may remain set! XXX
|
|
*/
|
|
toff = bp->b_bcount;
|
|
tinc = PAGE_SIZE - ((bp->b_offset + toff) & PAGE_MASK);
|
|
while ((bp->b_flags & B_CACHE) && toff < size) {
|
|
vm_pindex_t pi;
|
|
|
|
if (tinc > (size - toff))
|
|
tinc = size - toff;
|
|
pi = ((bp->b_offset & PAGE_MASK) + toff) >> PAGE_SHIFT;
|
|
m = bp->b_pages[pi];
|
|
vfs_buf_test_cache(bp, bp->b_offset, toff, tinc, m);
|
|
toff += tinc;
|
|
tinc = PAGE_SIZE;
|
|
}
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
|
|
/*
|
|
* Step 3, fixup the KVA pmap.
|
|
*/
|
|
if (buf_mapped(bp))
|
|
bpmap_qenter(bp);
|
|
else
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
}
|
|
|
|
/*
|
|
* Check to see if a block at a particular lbn is available for a clustered
|
|
* write.
|
|
*/
|
|
static int
|
|
vfs_bio_clcheck(struct vnode *vp, int size, daddr_t lblkno, daddr_t blkno)
|
|
{
|
|
struct buf *bpa;
|
|
int match;
|
|
|
|
match = 0;
|
|
|
|
/* If the buf isn't in core skip it */
|
|
if ((bpa = gbincore(&vp->v_bufobj, lblkno)) == NULL)
|
|
return (0);
|
|
|
|
/* If the buf is busy we don't want to wait for it */
|
|
if (BUF_LOCK(bpa, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0)
|
|
return (0);
|
|
|
|
/* Only cluster with valid clusterable delayed write buffers */
|
|
if ((bpa->b_flags & (B_DELWRI | B_CLUSTEROK | B_INVAL)) !=
|
|
(B_DELWRI | B_CLUSTEROK))
|
|
goto done;
|
|
|
|
if (bpa->b_bufsize != size)
|
|
goto done;
|
|
|
|
/*
|
|
* Check to see if it is in the expected place on disk and that the
|
|
* block has been mapped.
|
|
*/
|
|
if ((bpa->b_blkno != bpa->b_lblkno) && (bpa->b_blkno == blkno))
|
|
match = 1;
|
|
done:
|
|
BUF_UNLOCK(bpa);
|
|
return (match);
|
|
}
|
|
|
|
/*
|
|
* vfs_bio_awrite:
|
|
*
|
|
* Implement clustered async writes for clearing out B_DELWRI buffers.
|
|
* This is much better then the old way of writing only one buffer at
|
|
* a time. Note that we may not be presented with the buffers in the
|
|
* correct order, so we search for the cluster in both directions.
|
|
*/
|
|
int
|
|
vfs_bio_awrite(struct buf *bp)
|
|
{
|
|
struct bufobj *bo;
|
|
int i;
|
|
int j;
|
|
daddr_t lblkno = bp->b_lblkno;
|
|
struct vnode *vp = bp->b_vp;
|
|
int ncl;
|
|
int nwritten;
|
|
int size;
|
|
int maxcl;
|
|
int gbflags;
|
|
|
|
bo = &vp->v_bufobj;
|
|
gbflags = (bp->b_data == unmapped_buf) ? GB_UNMAPPED : 0;
|
|
/*
|
|
* right now we support clustered writing only to regular files. If
|
|
* we find a clusterable block we could be in the middle of a cluster
|
|
* rather then at the beginning.
|
|
*/
|
|
if ((vp->v_type == VREG) &&
|
|
(vp->v_mount != 0) && /* Only on nodes that have the size info */
|
|
(bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) {
|
|
|
|
size = vp->v_mount->mnt_stat.f_iosize;
|
|
maxcl = MAXPHYS / size;
|
|
|
|
BO_RLOCK(bo);
|
|
for (i = 1; i < maxcl; i++)
|
|
if (vfs_bio_clcheck(vp, size, lblkno + i,
|
|
bp->b_blkno + ((i * size) >> DEV_BSHIFT)) == 0)
|
|
break;
|
|
|
|
for (j = 1; i + j <= maxcl && j <= lblkno; j++)
|
|
if (vfs_bio_clcheck(vp, size, lblkno - j,
|
|
bp->b_blkno - ((j * size) >> DEV_BSHIFT)) == 0)
|
|
break;
|
|
BO_RUNLOCK(bo);
|
|
--j;
|
|
ncl = i + j;
|
|
/*
|
|
* this is a possible cluster write
|
|
*/
|
|
if (ncl != 1) {
|
|
BUF_UNLOCK(bp);
|
|
nwritten = cluster_wbuild(vp, size, lblkno - j, ncl,
|
|
gbflags);
|
|
return (nwritten);
|
|
}
|
|
}
|
|
bremfree(bp);
|
|
bp->b_flags |= B_ASYNC;
|
|
/*
|
|
* default (old) behavior, writing out only one block
|
|
*
|
|
* XXX returns b_bufsize instead of b_bcount for nwritten?
|
|
*/
|
|
nwritten = bp->b_bufsize;
|
|
(void) bwrite(bp);
|
|
|
|
return (nwritten);
|
|
}
|
|
|
|
/*
|
|
* getnewbuf_kva:
|
|
*
|
|
* Allocate KVA for an empty buf header according to gbflags.
|
|
*/
|
|
static int
|
|
getnewbuf_kva(struct buf *bp, int gbflags, int maxsize)
|
|
{
|
|
|
|
if ((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_UNMAPPED) {
|
|
/*
|
|
* In order to keep fragmentation sane we only allocate kva
|
|
* in BKVASIZE chunks. XXX with vmem we can do page size.
|
|
*/
|
|
maxsize = (maxsize + BKVAMASK) & ~BKVAMASK;
|
|
|
|
if (maxsize != bp->b_kvasize &&
|
|
bufkva_alloc(bp, maxsize, gbflags))
|
|
return (ENOSPC);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* getnewbuf:
|
|
*
|
|
* Find and initialize a new buffer header, freeing up existing buffers
|
|
* in the bufqueues as necessary. The new buffer is returned locked.
|
|
*
|
|
* We block if:
|
|
* We have insufficient buffer headers
|
|
* We have insufficient buffer space
|
|
* buffer_arena is too fragmented ( space reservation fails )
|
|
* If we have to flush dirty buffers ( but we try to avoid this )
|
|
*
|
|
* The caller is responsible for releasing the reserved bufspace after
|
|
* allocbuf() is called.
|
|
*/
|
|
static struct buf *
|
|
getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int maxsize, int gbflags)
|
|
{
|
|
struct buf *bp;
|
|
bool metadata, reserved;
|
|
|
|
bp = NULL;
|
|
KASSERT((gbflags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC,
|
|
("GB_KVAALLOC only makes sense with GB_UNMAPPED"));
|
|
if (!unmapped_buf_allowed)
|
|
gbflags &= ~(GB_UNMAPPED | GB_KVAALLOC);
|
|
|
|
if (vp == NULL || (vp->v_vflag & (VV_MD | VV_SYSTEM)) != 0 ||
|
|
vp->v_type == VCHR)
|
|
metadata = true;
|
|
else
|
|
metadata = false;
|
|
atomic_add_int(&getnewbufcalls, 1);
|
|
reserved = false;
|
|
do {
|
|
if (reserved == false &&
|
|
bufspace_reserve(maxsize, metadata) != 0)
|
|
continue;
|
|
reserved = true;
|
|
if ((bp = buf_alloc()) == NULL)
|
|
continue;
|
|
if (getnewbuf_kva(bp, gbflags, maxsize) == 0)
|
|
return (bp);
|
|
break;
|
|
} while(buf_scan(false) == 0);
|
|
|
|
if (reserved)
|
|
atomic_subtract_long(&bufspace, maxsize);
|
|
if (bp != NULL) {
|
|
bp->b_flags |= B_INVAL;
|
|
brelse(bp);
|
|
}
|
|
bufspace_wait(vp, gbflags, slpflag, slptimeo);
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* buf_daemon:
|
|
*
|
|
* buffer flushing daemon. Buffers are normally flushed by the
|
|
* update daemon but if it cannot keep up this process starts to
|
|
* take the load in an attempt to prevent getnewbuf() from blocking.
|
|
*/
|
|
static struct kproc_desc buf_kp = {
|
|
"bufdaemon",
|
|
buf_daemon,
|
|
&bufdaemonproc
|
|
};
|
|
SYSINIT(bufdaemon, SI_SUB_KTHREAD_BUF, SI_ORDER_FIRST, kproc_start, &buf_kp);
|
|
|
|
static int
|
|
buf_flush(struct vnode *vp, int target)
|
|
{
|
|
int flushed;
|
|
|
|
flushed = flushbufqueues(vp, target, 0);
|
|
if (flushed == 0) {
|
|
/*
|
|
* Could not find any buffers without rollback
|
|
* dependencies, so just write the first one
|
|
* in the hopes of eventually making progress.
|
|
*/
|
|
if (vp != NULL && target > 2)
|
|
target /= 2;
|
|
flushbufqueues(vp, target, 1);
|
|
}
|
|
return (flushed);
|
|
}
|
|
|
|
static void
|
|
buf_daemon()
|
|
{
|
|
int lodirty;
|
|
|
|
/*
|
|
* This process needs to be suspended prior to shutdown sync.
|
|
*/
|
|
EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, bufdaemonproc,
|
|
SHUTDOWN_PRI_LAST);
|
|
|
|
/*
|
|
* This process is allowed to take the buffer cache to the limit
|
|
*/
|
|
curthread->td_pflags |= TDP_NORUNNINGBUF | TDP_BUFNEED;
|
|
mtx_lock(&bdlock);
|
|
for (;;) {
|
|
bd_request = 0;
|
|
mtx_unlock(&bdlock);
|
|
|
|
kproc_suspend_check(bufdaemonproc);
|
|
lodirty = lodirtybuffers;
|
|
if (bd_speedupreq) {
|
|
lodirty = numdirtybuffers / 2;
|
|
bd_speedupreq = 0;
|
|
}
|
|
/*
|
|
* Do the flush. Limit the amount of in-transit I/O we
|
|
* allow to build up, otherwise we would completely saturate
|
|
* the I/O system.
|
|
*/
|
|
while (numdirtybuffers > lodirty) {
|
|
if (buf_flush(NULL, numdirtybuffers - lodirty) == 0)
|
|
break;
|
|
kern_yield(PRI_USER);
|
|
}
|
|
|
|
/*
|
|
* Only clear bd_request if we have reached our low water
|
|
* mark. The buf_daemon normally waits 1 second and
|
|
* then incrementally flushes any dirty buffers that have
|
|
* built up, within reason.
|
|
*
|
|
* If we were unable to hit our low water mark and couldn't
|
|
* find any flushable buffers, we sleep for a short period
|
|
* to avoid endless loops on unlockable buffers.
|
|
*/
|
|
mtx_lock(&bdlock);
|
|
if (numdirtybuffers <= lodirtybuffers) {
|
|
/*
|
|
* We reached our low water mark, reset the
|
|
* request and sleep until we are needed again.
|
|
* The sleep is just so the suspend code works.
|
|
*/
|
|
bd_request = 0;
|
|
/*
|
|
* Do an extra wakeup in case dirty threshold
|
|
* changed via sysctl and the explicit transition
|
|
* out of shortfall was missed.
|
|
*/
|
|
bdirtywakeup();
|
|
if (runningbufspace <= lorunningspace)
|
|
runningwakeup();
|
|
msleep(&bd_request, &bdlock, PVM, "psleep", hz);
|
|
} else {
|
|
/*
|
|
* We couldn't find any flushable dirty buffers but
|
|
* still have too many dirty buffers, we
|
|
* have to sleep and try again. (rare)
|
|
*/
|
|
msleep(&bd_request, &bdlock, PVM, "qsleep", hz / 10);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* flushbufqueues:
|
|
*
|
|
* Try to flush a buffer in the dirty queue. We must be careful to
|
|
* free up B_INVAL buffers instead of write them, which NFS is
|
|
* particularly sensitive to.
|
|
*/
|
|
static int flushwithdeps = 0;
|
|
SYSCTL_INT(_vfs, OID_AUTO, flushwithdeps, CTLFLAG_RW, &flushwithdeps,
|
|
0, "Number of buffers flushed with dependecies that require rollbacks");
|
|
|
|
static int
|
|
flushbufqueues(struct vnode *lvp, int target, int flushdeps)
|
|
{
|
|
struct buf *sentinel;
|
|
struct vnode *vp;
|
|
struct mount *mp;
|
|
struct buf *bp;
|
|
int hasdeps;
|
|
int flushed;
|
|
int queue;
|
|
int error;
|
|
bool unlock;
|
|
|
|
flushed = 0;
|
|
queue = QUEUE_DIRTY;
|
|
bp = NULL;
|
|
sentinel = malloc(sizeof(struct buf), M_TEMP, M_WAITOK | M_ZERO);
|
|
sentinel->b_qindex = QUEUE_SENTINEL;
|
|
mtx_lock(&bqlocks[queue]);
|
|
TAILQ_INSERT_HEAD(&bufqueues[queue], sentinel, b_freelist);
|
|
mtx_unlock(&bqlocks[queue]);
|
|
while (flushed != target) {
|
|
maybe_yield();
|
|
mtx_lock(&bqlocks[queue]);
|
|
bp = TAILQ_NEXT(sentinel, b_freelist);
|
|
if (bp != NULL) {
|
|
TAILQ_REMOVE(&bufqueues[queue], sentinel, b_freelist);
|
|
TAILQ_INSERT_AFTER(&bufqueues[queue], bp, sentinel,
|
|
b_freelist);
|
|
} else {
|
|
mtx_unlock(&bqlocks[queue]);
|
|
break;
|
|
}
|
|
/*
|
|
* Skip sentinels inserted by other invocations of the
|
|
* flushbufqueues(), taking care to not reorder them.
|
|
*
|
|
* Only flush the buffers that belong to the
|
|
* vnode locked by the curthread.
|
|
*/
|
|
if (bp->b_qindex == QUEUE_SENTINEL || (lvp != NULL &&
|
|
bp->b_vp != lvp)) {
|
|
mtx_unlock(&bqlocks[queue]);
|
|
continue;
|
|
}
|
|
error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL);
|
|
mtx_unlock(&bqlocks[queue]);
|
|
if (error != 0)
|
|
continue;
|
|
|
|
/*
|
|
* BKGRDINPROG can only be set with the buf and bufobj
|
|
* locks both held. We tolerate a race to clear it here.
|
|
*/
|
|
if ((bp->b_vflags & BV_BKGRDINPROG) != 0 ||
|
|
(bp->b_flags & B_DELWRI) == 0) {
|
|
BUF_UNLOCK(bp);
|
|
continue;
|
|
}
|
|
if (bp->b_flags & B_INVAL) {
|
|
bremfreef(bp);
|
|
brelse(bp);
|
|
flushed++;
|
|
continue;
|
|
}
|
|
|
|
if (!LIST_EMPTY(&bp->b_dep) && buf_countdeps(bp, 0)) {
|
|
if (flushdeps == 0) {
|
|
BUF_UNLOCK(bp);
|
|
continue;
|
|
}
|
|
hasdeps = 1;
|
|
} else
|
|
hasdeps = 0;
|
|
/*
|
|
* We must hold the lock on a vnode before writing
|
|
* one of its buffers. Otherwise we may confuse, or
|
|
* in the case of a snapshot vnode, deadlock the
|
|
* system.
|
|
*
|
|
* The lock order here is the reverse of the normal
|
|
* of vnode followed by buf lock. This is ok because
|
|
* the NOWAIT will prevent deadlock.
|
|
*/
|
|
vp = bp->b_vp;
|
|
if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
|
|
BUF_UNLOCK(bp);
|
|
continue;
|
|
}
|
|
if (lvp == NULL) {
|
|
unlock = true;
|
|
error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT);
|
|
} else {
|
|
ASSERT_VOP_LOCKED(vp, "getbuf");
|
|
unlock = false;
|
|
error = VOP_ISLOCKED(vp) == LK_EXCLUSIVE ? 0 :
|
|
vn_lock(vp, LK_TRYUPGRADE);
|
|
}
|
|
if (error == 0) {
|
|
CTR3(KTR_BUF, "flushbufqueue(%p) vp %p flags %X",
|
|
bp, bp->b_vp, bp->b_flags);
|
|
if (curproc == bufdaemonproc) {
|
|
vfs_bio_awrite(bp);
|
|
} else {
|
|
bremfree(bp);
|
|
bwrite(bp);
|
|
notbufdflushes++;
|
|
}
|
|
vn_finished_write(mp);
|
|
if (unlock)
|
|
VOP_UNLOCK(vp, 0);
|
|
flushwithdeps += hasdeps;
|
|
flushed++;
|
|
|
|
/*
|
|
* Sleeping on runningbufspace while holding
|
|
* vnode lock leads to deadlock.
|
|
*/
|
|
if (curproc == bufdaemonproc &&
|
|
runningbufspace > hirunningspace)
|
|
waitrunningbufspace();
|
|
continue;
|
|
}
|
|
vn_finished_write(mp);
|
|
BUF_UNLOCK(bp);
|
|
}
|
|
mtx_lock(&bqlocks[queue]);
|
|
TAILQ_REMOVE(&bufqueues[queue], sentinel, b_freelist);
|
|
mtx_unlock(&bqlocks[queue]);
|
|
free(sentinel, M_TEMP);
|
|
return (flushed);
|
|
}
|
|
|
|
/*
|
|
* Check to see if a block is currently memory resident.
|
|
*/
|
|
struct buf *
|
|
incore(struct bufobj *bo, daddr_t blkno)
|
|
{
|
|
struct buf *bp;
|
|
|
|
BO_RLOCK(bo);
|
|
bp = gbincore(bo, blkno);
|
|
BO_RUNLOCK(bo);
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Returns true if no I/O is needed to access the
|
|
* associated VM object. This is like incore except
|
|
* it also hunts around in the VM system for the data.
|
|
*/
|
|
|
|
static int
|
|
inmem(struct vnode * vp, daddr_t blkno)
|
|
{
|
|
vm_object_t obj;
|
|
vm_offset_t toff, tinc, size;
|
|
vm_page_t m;
|
|
vm_ooffset_t off;
|
|
|
|
ASSERT_VOP_LOCKED(vp, "inmem");
|
|
|
|
if (incore(&vp->v_bufobj, blkno))
|
|
return 1;
|
|
if (vp->v_mount == NULL)
|
|
return 0;
|
|
obj = vp->v_object;
|
|
if (obj == NULL)
|
|
return (0);
|
|
|
|
size = PAGE_SIZE;
|
|
if (size > vp->v_mount->mnt_stat.f_iosize)
|
|
size = vp->v_mount->mnt_stat.f_iosize;
|
|
off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize;
|
|
|
|
VM_OBJECT_RLOCK(obj);
|
|
for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) {
|
|
m = vm_page_lookup(obj, OFF_TO_IDX(off + toff));
|
|
if (!m)
|
|
goto notinmem;
|
|
tinc = size;
|
|
if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK))
|
|
tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK);
|
|
if (vm_page_is_valid(m,
|
|
(vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0)
|
|
goto notinmem;
|
|
}
|
|
VM_OBJECT_RUNLOCK(obj);
|
|
return 1;
|
|
|
|
notinmem:
|
|
VM_OBJECT_RUNLOCK(obj);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Set the dirty range for a buffer based on the status of the dirty
|
|
* bits in the pages comprising the buffer. The range is limited
|
|
* to the size of the buffer.
|
|
*
|
|
* Tell the VM system that the pages associated with this buffer
|
|
* are clean. This is used for delayed writes where the data is
|
|
* going to go to disk eventually without additional VM intevention.
|
|
*
|
|
* Note that while we only really need to clean through to b_bcount, we
|
|
* just go ahead and clean through to b_bufsize.
|
|
*/
|
|
static void
|
|
vfs_clean_pages_dirty_buf(struct buf *bp)
|
|
{
|
|
vm_ooffset_t foff, noff, eoff;
|
|
vm_page_t m;
|
|
int i;
|
|
|
|
if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0)
|
|
return;
|
|
|
|
foff = bp->b_offset;
|
|
KASSERT(bp->b_offset != NOOFFSET,
|
|
("vfs_clean_pages_dirty_buf: no buffer offset"));
|
|
|
|
VM_OBJECT_WLOCK(bp->b_bufobj->bo_object);
|
|
vfs_drain_busy_pages(bp);
|
|
vfs_setdirty_locked_object(bp);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
|
|
eoff = noff;
|
|
if (eoff > bp->b_offset + bp->b_bufsize)
|
|
eoff = bp->b_offset + bp->b_bufsize;
|
|
m = bp->b_pages[i];
|
|
vfs_page_set_validclean(bp, foff, m);
|
|
/* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */
|
|
foff = noff;
|
|
}
|
|
VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object);
|
|
}
|
|
|
|
static void
|
|
vfs_setdirty_locked_object(struct buf *bp)
|
|
{
|
|
vm_object_t object;
|
|
int i;
|
|
|
|
object = bp->b_bufobj->bo_object;
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
|
|
/*
|
|
* We qualify the scan for modified pages on whether the
|
|
* object has been flushed yet.
|
|
*/
|
|
if ((object->flags & OBJ_MIGHTBEDIRTY) != 0) {
|
|
vm_offset_t boffset;
|
|
vm_offset_t eoffset;
|
|
|
|
/*
|
|
* test the pages to see if they have been modified directly
|
|
* by users through the VM system.
|
|
*/
|
|
for (i = 0; i < bp->b_npages; i++)
|
|
vm_page_test_dirty(bp->b_pages[i]);
|
|
|
|
/*
|
|
* Calculate the encompassing dirty range, boffset and eoffset,
|
|
* (eoffset - boffset) bytes.
|
|
*/
|
|
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
if (bp->b_pages[i]->dirty)
|
|
break;
|
|
}
|
|
boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK);
|
|
|
|
for (i = bp->b_npages - 1; i >= 0; --i) {
|
|
if (bp->b_pages[i]->dirty) {
|
|
break;
|
|
}
|
|
}
|
|
eoffset = ((i + 1) << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK);
|
|
|
|
/*
|
|
* Fit it to the buffer.
|
|
*/
|
|
|
|
if (eoffset > bp->b_bcount)
|
|
eoffset = bp->b_bcount;
|
|
|
|
/*
|
|
* If we have a good dirty range, merge with the existing
|
|
* dirty range.
|
|
*/
|
|
|
|
if (boffset < eoffset) {
|
|
if (bp->b_dirtyoff > boffset)
|
|
bp->b_dirtyoff = boffset;
|
|
if (bp->b_dirtyend < eoffset)
|
|
bp->b_dirtyend = eoffset;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allocate the KVA mapping for an existing buffer.
|
|
* If an unmapped buffer is provided but a mapped buffer is requested, take
|
|
* also care to properly setup mappings between pages and KVA.
|
|
*/
|
|
static void
|
|
bp_unmapped_get_kva(struct buf *bp, daddr_t blkno, int size, int gbflags)
|
|
{
|
|
int bsize, maxsize, need_mapping, need_kva;
|
|
off_t offset;
|
|
|
|
need_mapping = bp->b_data == unmapped_buf &&
|
|
(gbflags & GB_UNMAPPED) == 0;
|
|
need_kva = bp->b_kvabase == unmapped_buf &&
|
|
bp->b_data == unmapped_buf &&
|
|
(gbflags & GB_KVAALLOC) != 0;
|
|
if (!need_mapping && !need_kva)
|
|
return;
|
|
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
|
|
if (need_mapping && bp->b_kvabase != unmapped_buf) {
|
|
/*
|
|
* Buffer is not mapped, but the KVA was already
|
|
* reserved at the time of the instantiation. Use the
|
|
* allocated space.
|
|
*/
|
|
goto has_addr;
|
|
}
|
|
|
|
/*
|
|
* Calculate the amount of the address space we would reserve
|
|
* if the buffer was mapped.
|
|
*/
|
|
bsize = vn_isdisk(bp->b_vp, NULL) ? DEV_BSIZE : bp->b_bufobj->bo_bsize;
|
|
KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize"));
|
|
offset = blkno * bsize;
|
|
maxsize = size + (offset & PAGE_MASK);
|
|
maxsize = imax(maxsize, bsize);
|
|
|
|
while (bufkva_alloc(bp, maxsize, gbflags) != 0) {
|
|
if ((gbflags & GB_NOWAIT_BD) != 0) {
|
|
/*
|
|
* XXXKIB: defragmentation cannot
|
|
* succeed, not sure what else to do.
|
|
*/
|
|
panic("GB_NOWAIT_BD and GB_UNMAPPED %p", bp);
|
|
}
|
|
atomic_add_int(&mappingrestarts, 1);
|
|
bufspace_wait(bp->b_vp, gbflags, 0, 0);
|
|
}
|
|
has_addr:
|
|
if (need_mapping) {
|
|
/* b_offset is handled by bpmap_qenter. */
|
|
bp->b_data = bp->b_kvabase;
|
|
BUF_CHECK_MAPPED(bp);
|
|
bpmap_qenter(bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* getblk:
|
|
*
|
|
* Get a block given a specified block and offset into a file/device.
|
|
* The buffers B_DONE bit will be cleared on return, making it almost
|
|
* ready for an I/O initiation. B_INVAL may or may not be set on
|
|
* return. The caller should clear B_INVAL prior to initiating a
|
|
* READ.
|
|
*
|
|
* For a non-VMIO buffer, B_CACHE is set to the opposite of B_INVAL for
|
|
* an existing buffer.
|
|
*
|
|
* For a VMIO buffer, B_CACHE is modified according to the backing VM.
|
|
* If getblk()ing a previously 0-sized invalid buffer, B_CACHE is set
|
|
* and then cleared based on the backing VM. If the previous buffer is
|
|
* non-0-sized but invalid, B_CACHE will be cleared.
|
|
*
|
|
* If getblk() must create a new buffer, the new buffer is returned with
|
|
* both B_INVAL and B_CACHE clear unless it is a VMIO buffer, in which
|
|
* case it is returned with B_INVAL clear and B_CACHE set based on the
|
|
* backing VM.
|
|
*
|
|
* getblk() also forces a bwrite() for any B_DELWRI buffer whos
|
|
* B_CACHE bit is clear.
|
|
*
|
|
* What this means, basically, is that the caller should use B_CACHE to
|
|
* determine whether the buffer is fully valid or not and should clear
|
|
* B_INVAL prior to issuing a read. If the caller intends to validate
|
|
* the buffer by loading its data area with something, the caller needs
|
|
* to clear B_INVAL. If the caller does this without issuing an I/O,
|
|
* the caller should set B_CACHE ( as an optimization ), else the caller
|
|
* should issue the I/O and biodone() will set B_CACHE if the I/O was
|
|
* a write attempt or if it was a successful read. If the caller
|
|
* intends to issue a READ, the caller must clear B_INVAL and BIO_ERROR
|
|
* prior to issuing the READ. biodone() will *not* clear B_INVAL.
|
|
*/
|
|
struct buf *
|
|
getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo,
|
|
int flags)
|
|
{
|
|
struct buf *bp;
|
|
struct bufobj *bo;
|
|
int bsize, error, maxsize, vmio;
|
|
off_t offset;
|
|
|
|
CTR3(KTR_BUF, "getblk(%p, %ld, %d)", vp, (long)blkno, size);
|
|
KASSERT((flags & (GB_UNMAPPED | GB_KVAALLOC)) != GB_KVAALLOC,
|
|
("GB_KVAALLOC only makes sense with GB_UNMAPPED"));
|
|
ASSERT_VOP_LOCKED(vp, "getblk");
|
|
if (size > MAXBCACHEBUF)
|
|
panic("getblk: size(%d) > MAXBCACHEBUF(%d)\n", size,
|
|
MAXBCACHEBUF);
|
|
if (!unmapped_buf_allowed)
|
|
flags &= ~(GB_UNMAPPED | GB_KVAALLOC);
|
|
|
|
bo = &vp->v_bufobj;
|
|
loop:
|
|
BO_RLOCK(bo);
|
|
bp = gbincore(bo, blkno);
|
|
if (bp != NULL) {
|
|
int lockflags;
|
|
/*
|
|
* Buffer is in-core. If the buffer is not busy nor managed,
|
|
* it must be on a queue.
|
|
*/
|
|
lockflags = LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK;
|
|
|
|
if (flags & GB_LOCK_NOWAIT)
|
|
lockflags |= LK_NOWAIT;
|
|
|
|
error = BUF_TIMELOCK(bp, lockflags,
|
|
BO_LOCKPTR(bo), "getblk", slpflag, slptimeo);
|
|
|
|
/*
|
|
* If we slept and got the lock we have to restart in case
|
|
* the buffer changed identities.
|
|
*/
|
|
if (error == ENOLCK)
|
|
goto loop;
|
|
/* We timed out or were interrupted. */
|
|
else if (error)
|
|
return (NULL);
|
|
/* If recursed, assume caller knows the rules. */
|
|
else if (BUF_LOCKRECURSED(bp))
|
|
goto end;
|
|
|
|
/*
|
|
* The buffer is locked. B_CACHE is cleared if the buffer is
|
|
* invalid. Otherwise, for a non-VMIO buffer, B_CACHE is set
|
|
* and for a VMIO buffer B_CACHE is adjusted according to the
|
|
* backing VM cache.
|
|
*/
|
|
if (bp->b_flags & B_INVAL)
|
|
bp->b_flags &= ~B_CACHE;
|
|
else if ((bp->b_flags & (B_VMIO | B_INVAL)) == 0)
|
|
bp->b_flags |= B_CACHE;
|
|
if (bp->b_flags & B_MANAGED)
|
|
MPASS(bp->b_qindex == QUEUE_NONE);
|
|
else
|
|
bremfree(bp);
|
|
|
|
/*
|
|
* check for size inconsistencies for non-VMIO case.
|
|
*/
|
|
if (bp->b_bcount != size) {
|
|
if ((bp->b_flags & B_VMIO) == 0 ||
|
|
(size > bp->b_kvasize)) {
|
|
if (bp->b_flags & B_DELWRI) {
|
|
bp->b_flags |= B_NOCACHE;
|
|
bwrite(bp);
|
|
} else {
|
|
if (LIST_EMPTY(&bp->b_dep)) {
|
|
bp->b_flags |= B_RELBUF;
|
|
brelse(bp);
|
|
} else {
|
|
bp->b_flags |= B_NOCACHE;
|
|
bwrite(bp);
|
|
}
|
|
}
|
|
goto loop;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Handle the case of unmapped buffer which should
|
|
* become mapped, or the buffer for which KVA
|
|
* reservation is requested.
|
|
*/
|
|
bp_unmapped_get_kva(bp, blkno, size, flags);
|
|
|
|
/*
|
|
* If the size is inconsistent in the VMIO case, we can resize
|
|
* the buffer. This might lead to B_CACHE getting set or
|
|
* cleared. If the size has not changed, B_CACHE remains
|
|
* unchanged from its previous state.
|
|
*/
|
|
allocbuf(bp, size);
|
|
|
|
KASSERT(bp->b_offset != NOOFFSET,
|
|
("getblk: no buffer offset"));
|
|
|
|
/*
|
|
* A buffer with B_DELWRI set and B_CACHE clear must
|
|
* be committed before we can return the buffer in
|
|
* order to prevent the caller from issuing a read
|
|
* ( due to B_CACHE not being set ) and overwriting
|
|
* it.
|
|
*
|
|
* Most callers, including NFS and FFS, need this to
|
|
* operate properly either because they assume they
|
|
* can issue a read if B_CACHE is not set, or because
|
|
* ( for example ) an uncached B_DELWRI might loop due
|
|
* to softupdates re-dirtying the buffer. In the latter
|
|
* case, B_CACHE is set after the first write completes,
|
|
* preventing further loops.
|
|
* NOTE! b*write() sets B_CACHE. If we cleared B_CACHE
|
|
* above while extending the buffer, we cannot allow the
|
|
* buffer to remain with B_CACHE set after the write
|
|
* completes or it will represent a corrupt state. To
|
|
* deal with this we set B_NOCACHE to scrap the buffer
|
|
* after the write.
|
|
*
|
|
* We might be able to do something fancy, like setting
|
|
* B_CACHE in bwrite() except if B_DELWRI is already set,
|
|
* so the below call doesn't set B_CACHE, but that gets real
|
|
* confusing. This is much easier.
|
|
*/
|
|
|
|
if ((bp->b_flags & (B_CACHE|B_DELWRI)) == B_DELWRI) {
|
|
bp->b_flags |= B_NOCACHE;
|
|
bwrite(bp);
|
|
goto loop;
|
|
}
|
|
bp->b_flags &= ~B_DONE;
|
|
} else {
|
|
/*
|
|
* Buffer is not in-core, create new buffer. The buffer
|
|
* returned by getnewbuf() is locked. Note that the returned
|
|
* buffer is also considered valid (not marked B_INVAL).
|
|
*/
|
|
BO_RUNLOCK(bo);
|
|
/*
|
|
* If the user does not want us to create the buffer, bail out
|
|
* here.
|
|
*/
|
|
if (flags & GB_NOCREAT)
|
|
return NULL;
|
|
if (numfreebuffers == 0 && TD_IS_IDLETHREAD(curthread))
|
|
return NULL;
|
|
|
|
bsize = vn_isdisk(vp, NULL) ? DEV_BSIZE : bo->bo_bsize;
|
|
KASSERT(bsize != 0, ("bsize == 0, check bo->bo_bsize"));
|
|
offset = blkno * bsize;
|
|
vmio = vp->v_object != NULL;
|
|
if (vmio) {
|
|
maxsize = size + (offset & PAGE_MASK);
|
|
} else {
|
|
maxsize = size;
|
|
/* Do not allow non-VMIO notmapped buffers. */
|
|
flags &= ~(GB_UNMAPPED | GB_KVAALLOC);
|
|
}
|
|
maxsize = imax(maxsize, bsize);
|
|
|
|
bp = getnewbuf(vp, slpflag, slptimeo, maxsize, flags);
|
|
if (bp == NULL) {
|
|
if (slpflag || slptimeo)
|
|
return NULL;
|
|
/*
|
|
* XXX This is here until the sleep path is diagnosed
|
|
* enough to work under very low memory conditions.
|
|
*
|
|
* There's an issue on low memory, 4BSD+non-preempt
|
|
* systems (eg MIPS routers with 32MB RAM) where buffer
|
|
* exhaustion occurs without sleeping for buffer
|
|
* reclaimation. This just sticks in a loop and
|
|
* constantly attempts to allocate a buffer, which
|
|
* hits exhaustion and tries to wakeup bufdaemon.
|
|
* This never happens because we never yield.
|
|
*
|
|
* The real solution is to identify and fix these cases
|
|
* so we aren't effectively busy-waiting in a loop
|
|
* until the reclaimation path has cycles to run.
|
|
*/
|
|
kern_yield(PRI_USER);
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* This code is used to make sure that a buffer is not
|
|
* created while the getnewbuf routine is blocked.
|
|
* This can be a problem whether the vnode is locked or not.
|
|
* If the buffer is created out from under us, we have to
|
|
* throw away the one we just created.
|
|
*
|
|
* Note: this must occur before we associate the buffer
|
|
* with the vp especially considering limitations in
|
|
* the splay tree implementation when dealing with duplicate
|
|
* lblkno's.
|
|
*/
|
|
BO_LOCK(bo);
|
|
if (gbincore(bo, blkno)) {
|
|
BO_UNLOCK(bo);
|
|
bp->b_flags |= B_INVAL;
|
|
brelse(bp);
|
|
bufspace_release(maxsize);
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* Insert the buffer into the hash, so that it can
|
|
* be found by incore.
|
|
*/
|
|
bp->b_blkno = bp->b_lblkno = blkno;
|
|
bp->b_offset = offset;
|
|
bgetvp(vp, bp);
|
|
BO_UNLOCK(bo);
|
|
|
|
/*
|
|
* set B_VMIO bit. allocbuf() the buffer bigger. Since the
|
|
* buffer size starts out as 0, B_CACHE will be set by
|
|
* allocbuf() for the VMIO case prior to it testing the
|
|
* backing store for validity.
|
|
*/
|
|
|
|
if (vmio) {
|
|
bp->b_flags |= B_VMIO;
|
|
KASSERT(vp->v_object == bp->b_bufobj->bo_object,
|
|
("ARGH! different b_bufobj->bo_object %p %p %p\n",
|
|
bp, vp->v_object, bp->b_bufobj->bo_object));
|
|
} else {
|
|
bp->b_flags &= ~B_VMIO;
|
|
KASSERT(bp->b_bufobj->bo_object == NULL,
|
|
("ARGH! has b_bufobj->bo_object %p %p\n",
|
|
bp, bp->b_bufobj->bo_object));
|
|
BUF_CHECK_MAPPED(bp);
|
|
}
|
|
|
|
allocbuf(bp, size);
|
|
bufspace_release(maxsize);
|
|
bp->b_flags &= ~B_DONE;
|
|
}
|
|
CTR4(KTR_BUF, "getblk(%p, %ld, %d) = %p", vp, (long)blkno, size, bp);
|
|
BUF_ASSERT_HELD(bp);
|
|
end:
|
|
KASSERT(bp->b_bufobj == bo,
|
|
("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Get an empty, disassociated buffer of given size. The buffer is initially
|
|
* set to B_INVAL.
|
|
*/
|
|
struct buf *
|
|
geteblk(int size, int flags)
|
|
{
|
|
struct buf *bp;
|
|
int maxsize;
|
|
|
|
maxsize = (size + BKVAMASK) & ~BKVAMASK;
|
|
while ((bp = getnewbuf(NULL, 0, 0, maxsize, flags)) == NULL) {
|
|
if ((flags & GB_NOWAIT_BD) &&
|
|
(curthread->td_pflags & TDP_BUFNEED) != 0)
|
|
return (NULL);
|
|
}
|
|
allocbuf(bp, size);
|
|
bufspace_release(maxsize);
|
|
bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */
|
|
BUF_ASSERT_HELD(bp);
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Truncate the backing store for a non-vmio buffer.
|
|
*/
|
|
static void
|
|
vfs_nonvmio_truncate(struct buf *bp, int newbsize)
|
|
{
|
|
|
|
if (bp->b_flags & B_MALLOC) {
|
|
/*
|
|
* malloced buffers are not shrunk
|
|
*/
|
|
if (newbsize == 0) {
|
|
bufmallocadjust(bp, 0);
|
|
free(bp->b_data, M_BIOBUF);
|
|
bp->b_data = bp->b_kvabase;
|
|
bp->b_flags &= ~B_MALLOC;
|
|
}
|
|
return;
|
|
}
|
|
vm_hold_free_pages(bp, newbsize);
|
|
bufspace_adjust(bp, newbsize);
|
|
}
|
|
|
|
/*
|
|
* Extend the backing for a non-VMIO buffer.
|
|
*/
|
|
static void
|
|
vfs_nonvmio_extend(struct buf *bp, int newbsize)
|
|
{
|
|
caddr_t origbuf;
|
|
int origbufsize;
|
|
|
|
/*
|
|
* We only use malloced memory on the first allocation.
|
|
* and revert to page-allocated memory when the buffer
|
|
* grows.
|
|
*
|
|
* There is a potential smp race here that could lead
|
|
* to bufmallocspace slightly passing the max. It
|
|
* is probably extremely rare and not worth worrying
|
|
* over.
|
|
*/
|
|
if (bp->b_bufsize == 0 && newbsize <= PAGE_SIZE/2 &&
|
|
bufmallocspace < maxbufmallocspace) {
|
|
bp->b_data = malloc(newbsize, M_BIOBUF, M_WAITOK);
|
|
bp->b_flags |= B_MALLOC;
|
|
bufmallocadjust(bp, newbsize);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If the buffer is growing on its other-than-first
|
|
* allocation then we revert to the page-allocation
|
|
* scheme.
|
|
*/
|
|
origbuf = NULL;
|
|
origbufsize = 0;
|
|
if (bp->b_flags & B_MALLOC) {
|
|
origbuf = bp->b_data;
|
|
origbufsize = bp->b_bufsize;
|
|
bp->b_data = bp->b_kvabase;
|
|
bufmallocadjust(bp, 0);
|
|
bp->b_flags &= ~B_MALLOC;
|
|
newbsize = round_page(newbsize);
|
|
}
|
|
vm_hold_load_pages(bp, (vm_offset_t) bp->b_data + bp->b_bufsize,
|
|
(vm_offset_t) bp->b_data + newbsize);
|
|
if (origbuf != NULL) {
|
|
bcopy(origbuf, bp->b_data, origbufsize);
|
|
free(origbuf, M_BIOBUF);
|
|
}
|
|
bufspace_adjust(bp, newbsize);
|
|
}
|
|
|
|
/*
|
|
* This code constitutes the buffer memory from either anonymous system
|
|
* memory (in the case of non-VMIO operations) or from an associated
|
|
* VM object (in the case of VMIO operations). This code is able to
|
|
* resize a buffer up or down.
|
|
*
|
|
* Note that this code is tricky, and has many complications to resolve
|
|
* deadlock or inconsistent data situations. Tread lightly!!!
|
|
* There are B_CACHE and B_DELWRI interactions that must be dealt with by
|
|
* the caller. Calling this code willy nilly can result in the loss of data.
|
|
*
|
|
* allocbuf() only adjusts B_CACHE for VMIO buffers. getblk() deals with
|
|
* B_CACHE for the non-VMIO case.
|
|
*/
|
|
int
|
|
allocbuf(struct buf *bp, int size)
|
|
{
|
|
int newbsize;
|
|
|
|
BUF_ASSERT_HELD(bp);
|
|
|
|
if (bp->b_bcount == size)
|
|
return (1);
|
|
|
|
if (bp->b_kvasize != 0 && bp->b_kvasize < size)
|
|
panic("allocbuf: buffer too small");
|
|
|
|
newbsize = roundup2(size, DEV_BSIZE);
|
|
if ((bp->b_flags & B_VMIO) == 0) {
|
|
if ((bp->b_flags & B_MALLOC) == 0)
|
|
newbsize = round_page(newbsize);
|
|
/*
|
|
* Just get anonymous memory from the kernel. Don't
|
|
* mess with B_CACHE.
|
|
*/
|
|
if (newbsize < bp->b_bufsize)
|
|
vfs_nonvmio_truncate(bp, newbsize);
|
|
else if (newbsize > bp->b_bufsize)
|
|
vfs_nonvmio_extend(bp, newbsize);
|
|
} else {
|
|
int desiredpages;
|
|
|
|
desiredpages = (size == 0) ? 0 :
|
|
num_pages((bp->b_offset & PAGE_MASK) + newbsize);
|
|
|
|
if (bp->b_flags & B_MALLOC)
|
|
panic("allocbuf: VMIO buffer can't be malloced");
|
|
/*
|
|
* Set B_CACHE initially if buffer is 0 length or will become
|
|
* 0-length.
|
|
*/
|
|
if (size == 0 || bp->b_bufsize == 0)
|
|
bp->b_flags |= B_CACHE;
|
|
|
|
if (newbsize < bp->b_bufsize)
|
|
vfs_vmio_truncate(bp, desiredpages);
|
|
/* XXX This looks as if it should be newbsize > b_bufsize */
|
|
else if (size > bp->b_bcount)
|
|
vfs_vmio_extend(bp, desiredpages, size);
|
|
bufspace_adjust(bp, newbsize);
|
|
}
|
|
bp->b_bcount = size; /* requested buffer size. */
|
|
return (1);
|
|
}
|
|
|
|
extern int inflight_transient_maps;
|
|
|
|
void
|
|
biodone(struct bio *bp)
|
|
{
|
|
struct mtx *mtxp;
|
|
void (*done)(struct bio *);
|
|
vm_offset_t start, end;
|
|
|
|
if ((bp->bio_flags & BIO_TRANSIENT_MAPPING) != 0) {
|
|
bp->bio_flags &= ~BIO_TRANSIENT_MAPPING;
|
|
bp->bio_flags |= BIO_UNMAPPED;
|
|
start = trunc_page((vm_offset_t)bp->bio_data);
|
|
end = round_page((vm_offset_t)bp->bio_data + bp->bio_length);
|
|
bp->bio_data = unmapped_buf;
|
|
pmap_qremove(start, OFF_TO_IDX(end - start));
|
|
vmem_free(transient_arena, start, end - start);
|
|
atomic_add_int(&inflight_transient_maps, -1);
|
|
}
|
|
done = bp->bio_done;
|
|
if (done == NULL) {
|
|
mtxp = mtx_pool_find(mtxpool_sleep, bp);
|
|
mtx_lock(mtxp);
|
|
bp->bio_flags |= BIO_DONE;
|
|
wakeup(bp);
|
|
mtx_unlock(mtxp);
|
|
} else {
|
|
bp->bio_flags |= BIO_DONE;
|
|
done(bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Wait for a BIO to finish.
|
|
*/
|
|
int
|
|
biowait(struct bio *bp, const char *wchan)
|
|
{
|
|
struct mtx *mtxp;
|
|
|
|
mtxp = mtx_pool_find(mtxpool_sleep, bp);
|
|
mtx_lock(mtxp);
|
|
while ((bp->bio_flags & BIO_DONE) == 0)
|
|
msleep(bp, mtxp, PRIBIO, wchan, 0);
|
|
mtx_unlock(mtxp);
|
|
if (bp->bio_error != 0)
|
|
return (bp->bio_error);
|
|
if (!(bp->bio_flags & BIO_ERROR))
|
|
return (0);
|
|
return (EIO);
|
|
}
|
|
|
|
void
|
|
biofinish(struct bio *bp, struct devstat *stat, int error)
|
|
{
|
|
|
|
if (error) {
|
|
bp->bio_error = error;
|
|
bp->bio_flags |= BIO_ERROR;
|
|
}
|
|
if (stat != NULL)
|
|
devstat_end_transaction_bio(stat, bp);
|
|
biodone(bp);
|
|
}
|
|
|
|
/*
|
|
* bufwait:
|
|
*
|
|
* Wait for buffer I/O completion, returning error status. The buffer
|
|
* is left locked and B_DONE on return. B_EINTR is converted into an EINTR
|
|
* error and cleared.
|
|
*/
|
|
int
|
|
bufwait(struct buf *bp)
|
|
{
|
|
if (bp->b_iocmd == BIO_READ)
|
|
bwait(bp, PRIBIO, "biord");
|
|
else
|
|
bwait(bp, PRIBIO, "biowr");
|
|
if (bp->b_flags & B_EINTR) {
|
|
bp->b_flags &= ~B_EINTR;
|
|
return (EINTR);
|
|
}
|
|
if (bp->b_ioflags & BIO_ERROR) {
|
|
return (bp->b_error ? bp->b_error : EIO);
|
|
} else {
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* bufdone:
|
|
*
|
|
* Finish I/O on a buffer, optionally calling a completion function.
|
|
* This is usually called from an interrupt so process blocking is
|
|
* not allowed.
|
|
*
|
|
* biodone is also responsible for setting B_CACHE in a B_VMIO bp.
|
|
* In a non-VMIO bp, B_CACHE will be set on the next getblk()
|
|
* assuming B_INVAL is clear.
|
|
*
|
|
* For the VMIO case, we set B_CACHE if the op was a read and no
|
|
* read error occurred, or if the op was a write. B_CACHE is never
|
|
* set if the buffer is invalid or otherwise uncacheable.
|
|
*
|
|
* biodone does not mess with B_INVAL, allowing the I/O routine or the
|
|
* initiator to leave B_INVAL set to brelse the buffer out of existence
|
|
* in the biodone routine.
|
|
*/
|
|
void
|
|
bufdone(struct buf *bp)
|
|
{
|
|
struct bufobj *dropobj;
|
|
void (*biodone)(struct buf *);
|
|
|
|
CTR3(KTR_BUF, "bufdone(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
|
|
dropobj = NULL;
|
|
|
|
KASSERT(!(bp->b_flags & B_DONE), ("biodone: bp %p already done", bp));
|
|
BUF_ASSERT_HELD(bp);
|
|
|
|
runningbufwakeup(bp);
|
|
if (bp->b_iocmd == BIO_WRITE)
|
|
dropobj = bp->b_bufobj;
|
|
/* call optional completion function if requested */
|
|
if (bp->b_iodone != NULL) {
|
|
biodone = bp->b_iodone;
|
|
bp->b_iodone = NULL;
|
|
(*biodone) (bp);
|
|
if (dropobj)
|
|
bufobj_wdrop(dropobj);
|
|
return;
|
|
}
|
|
|
|
bufdone_finish(bp);
|
|
|
|
if (dropobj)
|
|
bufobj_wdrop(dropobj);
|
|
}
|
|
|
|
void
|
|
bufdone_finish(struct buf *bp)
|
|
{
|
|
BUF_ASSERT_HELD(bp);
|
|
|
|
if (!LIST_EMPTY(&bp->b_dep))
|
|
buf_complete(bp);
|
|
|
|
if (bp->b_flags & B_VMIO) {
|
|
/*
|
|
* Set B_CACHE if the op was a normal read and no error
|
|
* occurred. B_CACHE is set for writes in the b*write()
|
|
* routines.
|
|
*/
|
|
if (bp->b_iocmd == BIO_READ &&
|
|
!(bp->b_flags & (B_INVAL|B_NOCACHE)) &&
|
|
!(bp->b_ioflags & BIO_ERROR))
|
|
bp->b_flags |= B_CACHE;
|
|
vfs_vmio_iodone(bp);
|
|
}
|
|
|
|
/*
|
|
* For asynchronous completions, release the buffer now. The brelse
|
|
* will do a wakeup there if necessary - so no need to do a wakeup
|
|
* here in the async case. The sync case always needs to do a wakeup.
|
|
*/
|
|
if (bp->b_flags & B_ASYNC) {
|
|
if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_RELBUF)) ||
|
|
(bp->b_ioflags & BIO_ERROR))
|
|
brelse(bp);
|
|
else
|
|
bqrelse(bp);
|
|
} else
|
|
bdone(bp);
|
|
}
|
|
|
|
/*
|
|
* This routine is called in lieu of iodone in the case of
|
|
* incomplete I/O. This keeps the busy status for pages
|
|
* consistent.
|
|
*/
|
|
void
|
|
vfs_unbusy_pages(struct buf *bp)
|
|
{
|
|
int i;
|
|
vm_object_t obj;
|
|
vm_page_t m;
|
|
|
|
runningbufwakeup(bp);
|
|
if (!(bp->b_flags & B_VMIO))
|
|
return;
|
|
|
|
obj = bp->b_bufobj->bo_object;
|
|
VM_OBJECT_WLOCK(obj);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
if (m == bogus_page) {
|
|
m = vm_page_lookup(obj, OFF_TO_IDX(bp->b_offset) + i);
|
|
if (!m)
|
|
panic("vfs_unbusy_pages: page missing\n");
|
|
bp->b_pages[i] = m;
|
|
if (buf_mapped(bp)) {
|
|
BUF_CHECK_MAPPED(bp);
|
|
pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
|
|
bp->b_pages, bp->b_npages);
|
|
} else
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
}
|
|
vm_page_sunbusy(m);
|
|
}
|
|
vm_object_pip_wakeupn(obj, bp->b_npages);
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
}
|
|
|
|
/*
|
|
* vfs_page_set_valid:
|
|
*
|
|
* Set the valid bits in a page based on the supplied offset. The
|
|
* range is restricted to the buffer's size.
|
|
*
|
|
* This routine is typically called after a read completes.
|
|
*/
|
|
static void
|
|
vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m)
|
|
{
|
|
vm_ooffset_t eoff;
|
|
|
|
/*
|
|
* Compute the end offset, eoff, such that [off, eoff) does not span a
|
|
* page boundary and eoff is not greater than the end of the buffer.
|
|
* The end of the buffer, in this case, is our file EOF, not the
|
|
* allocation size of the buffer.
|
|
*/
|
|
eoff = (off + PAGE_SIZE) & ~(vm_ooffset_t)PAGE_MASK;
|
|
if (eoff > bp->b_offset + bp->b_bcount)
|
|
eoff = bp->b_offset + bp->b_bcount;
|
|
|
|
/*
|
|
* Set valid range. This is typically the entire buffer and thus the
|
|
* entire page.
|
|
*/
|
|
if (eoff > off)
|
|
vm_page_set_valid_range(m, off & PAGE_MASK, eoff - off);
|
|
}
|
|
|
|
/*
|
|
* vfs_page_set_validclean:
|
|
*
|
|
* Set the valid bits and clear the dirty bits in a page based on the
|
|
* supplied offset. The range is restricted to the buffer's size.
|
|
*/
|
|
static void
|
|
vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m)
|
|
{
|
|
vm_ooffset_t soff, eoff;
|
|
|
|
/*
|
|
* Start and end offsets in buffer. eoff - soff may not cross a
|
|
* page boundary or cross the end of the buffer. The end of the
|
|
* buffer, in this case, is our file EOF, not the allocation size
|
|
* of the buffer.
|
|
*/
|
|
soff = off;
|
|
eoff = (off + PAGE_SIZE) & ~(off_t)PAGE_MASK;
|
|
if (eoff > bp->b_offset + bp->b_bcount)
|
|
eoff = bp->b_offset + bp->b_bcount;
|
|
|
|
/*
|
|
* Set valid range. This is typically the entire buffer and thus the
|
|
* entire page.
|
|
*/
|
|
if (eoff > soff) {
|
|
vm_page_set_validclean(
|
|
m,
|
|
(vm_offset_t) (soff & PAGE_MASK),
|
|
(vm_offset_t) (eoff - soff)
|
|
);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Ensure that all buffer pages are not exclusive busied. If any page is
|
|
* exclusive busy, drain it.
|
|
*/
|
|
void
|
|
vfs_drain_busy_pages(struct buf *bp)
|
|
{
|
|
vm_page_t m;
|
|
int i, last_busied;
|
|
|
|
VM_OBJECT_ASSERT_WLOCKED(bp->b_bufobj->bo_object);
|
|
last_busied = 0;
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
if (vm_page_xbusied(m)) {
|
|
for (; last_busied < i; last_busied++)
|
|
vm_page_sbusy(bp->b_pages[last_busied]);
|
|
while (vm_page_xbusied(m)) {
|
|
vm_page_lock(m);
|
|
VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object);
|
|
vm_page_busy_sleep(m, "vbpage");
|
|
VM_OBJECT_WLOCK(bp->b_bufobj->bo_object);
|
|
}
|
|
}
|
|
}
|
|
for (i = 0; i < last_busied; i++)
|
|
vm_page_sunbusy(bp->b_pages[i]);
|
|
}
|
|
|
|
/*
|
|
* This routine is called before a device strategy routine.
|
|
* It is used to tell the VM system that paging I/O is in
|
|
* progress, and treat the pages associated with the buffer
|
|
* almost as being exclusive busy. Also the object paging_in_progress
|
|
* flag is handled to make sure that the object doesn't become
|
|
* inconsistent.
|
|
*
|
|
* Since I/O has not been initiated yet, certain buffer flags
|
|
* such as BIO_ERROR or B_INVAL may be in an inconsistent state
|
|
* and should be ignored.
|
|
*/
|
|
void
|
|
vfs_busy_pages(struct buf *bp, int clear_modify)
|
|
{
|
|
int i, bogus;
|
|
vm_object_t obj;
|
|
vm_ooffset_t foff;
|
|
vm_page_t m;
|
|
|
|
if (!(bp->b_flags & B_VMIO))
|
|
return;
|
|
|
|
obj = bp->b_bufobj->bo_object;
|
|
foff = bp->b_offset;
|
|
KASSERT(bp->b_offset != NOOFFSET,
|
|
("vfs_busy_pages: no buffer offset"));
|
|
VM_OBJECT_WLOCK(obj);
|
|
vfs_drain_busy_pages(bp);
|
|
if (bp->b_bufsize != 0)
|
|
vfs_setdirty_locked_object(bp);
|
|
bogus = 0;
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
|
|
if ((bp->b_flags & B_CLUSTER) == 0) {
|
|
vm_object_pip_add(obj, 1);
|
|
vm_page_sbusy(m);
|
|
}
|
|
/*
|
|
* When readying a buffer for a read ( i.e
|
|
* clear_modify == 0 ), it is important to do
|
|
* bogus_page replacement for valid pages in
|
|
* partially instantiated buffers. Partially
|
|
* instantiated buffers can, in turn, occur when
|
|
* reconstituting a buffer from its VM backing store
|
|
* base. We only have to do this if B_CACHE is
|
|
* clear ( which causes the I/O to occur in the
|
|
* first place ). The replacement prevents the read
|
|
* I/O from overwriting potentially dirty VM-backed
|
|
* pages. XXX bogus page replacement is, uh, bogus.
|
|
* It may not work properly with small-block devices.
|
|
* We need to find a better way.
|
|
*/
|
|
if (clear_modify) {
|
|
pmap_remove_write(m);
|
|
vfs_page_set_validclean(bp, foff, m);
|
|
} else if (m->valid == VM_PAGE_BITS_ALL &&
|
|
(bp->b_flags & B_CACHE) == 0) {
|
|
bp->b_pages[i] = bogus_page;
|
|
bogus++;
|
|
}
|
|
foff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
|
|
}
|
|
VM_OBJECT_WUNLOCK(obj);
|
|
if (bogus && buf_mapped(bp)) {
|
|
BUF_CHECK_MAPPED(bp);
|
|
pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
|
|
bp->b_pages, bp->b_npages);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vfs_bio_set_valid:
|
|
*
|
|
* Set the range within the buffer to valid. The range is
|
|
* relative to the beginning of the buffer, b_offset. Note that
|
|
* b_offset itself may be offset from the beginning of the first
|
|
* page.
|
|
*/
|
|
void
|
|
vfs_bio_set_valid(struct buf *bp, int base, int size)
|
|
{
|
|
int i, n;
|
|
vm_page_t m;
|
|
|
|
if (!(bp->b_flags & B_VMIO))
|
|
return;
|
|
|
|
/*
|
|
* Fixup base to be relative to beginning of first page.
|
|
* Set initial n to be the maximum number of bytes in the
|
|
* first page that can be validated.
|
|
*/
|
|
base += (bp->b_offset & PAGE_MASK);
|
|
n = PAGE_SIZE - (base & PAGE_MASK);
|
|
|
|
VM_OBJECT_WLOCK(bp->b_bufobj->bo_object);
|
|
for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) {
|
|
m = bp->b_pages[i];
|
|
if (n > size)
|
|
n = size;
|
|
vm_page_set_valid_range(m, base & PAGE_MASK, n);
|
|
base += n;
|
|
size -= n;
|
|
n = PAGE_SIZE;
|
|
}
|
|
VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object);
|
|
}
|
|
|
|
/*
|
|
* vfs_bio_clrbuf:
|
|
*
|
|
* If the specified buffer is a non-VMIO buffer, clear the entire
|
|
* buffer. If the specified buffer is a VMIO buffer, clear and
|
|
* validate only the previously invalid portions of the buffer.
|
|
* This routine essentially fakes an I/O, so we need to clear
|
|
* BIO_ERROR and B_INVAL.
|
|
*
|
|
* Note that while we only theoretically need to clear through b_bcount,
|
|
* we go ahead and clear through b_bufsize.
|
|
*/
|
|
void
|
|
vfs_bio_clrbuf(struct buf *bp)
|
|
{
|
|
int i, j, mask, sa, ea, slide;
|
|
|
|
if ((bp->b_flags & (B_VMIO | B_MALLOC)) != B_VMIO) {
|
|
clrbuf(bp);
|
|
return;
|
|
}
|
|
bp->b_flags &= ~B_INVAL;
|
|
bp->b_ioflags &= ~BIO_ERROR;
|
|
VM_OBJECT_WLOCK(bp->b_bufobj->bo_object);
|
|
if ((bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE) &&
|
|
(bp->b_offset & PAGE_MASK) == 0) {
|
|
if (bp->b_pages[0] == bogus_page)
|
|
goto unlock;
|
|
mask = (1 << (bp->b_bufsize / DEV_BSIZE)) - 1;
|
|
VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[0]->object);
|
|
if ((bp->b_pages[0]->valid & mask) == mask)
|
|
goto unlock;
|
|
if ((bp->b_pages[0]->valid & mask) == 0) {
|
|
pmap_zero_page_area(bp->b_pages[0], 0, bp->b_bufsize);
|
|
bp->b_pages[0]->valid |= mask;
|
|
goto unlock;
|
|
}
|
|
}
|
|
sa = bp->b_offset & PAGE_MASK;
|
|
slide = 0;
|
|
for (i = 0; i < bp->b_npages; i++, sa = 0) {
|
|
slide = imin(slide + PAGE_SIZE, bp->b_offset + bp->b_bufsize);
|
|
ea = slide & PAGE_MASK;
|
|
if (ea == 0)
|
|
ea = PAGE_SIZE;
|
|
if (bp->b_pages[i] == bogus_page)
|
|
continue;
|
|
j = sa / DEV_BSIZE;
|
|
mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
|
|
VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[i]->object);
|
|
if ((bp->b_pages[i]->valid & mask) == mask)
|
|
continue;
|
|
if ((bp->b_pages[i]->valid & mask) == 0)
|
|
pmap_zero_page_area(bp->b_pages[i], sa, ea - sa);
|
|
else {
|
|
for (; sa < ea; sa += DEV_BSIZE, j++) {
|
|
if ((bp->b_pages[i]->valid & (1 << j)) == 0) {
|
|
pmap_zero_page_area(bp->b_pages[i],
|
|
sa, DEV_BSIZE);
|
|
}
|
|
}
|
|
}
|
|
bp->b_pages[i]->valid |= mask;
|
|
}
|
|
unlock:
|
|
VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object);
|
|
bp->b_resid = 0;
|
|
}
|
|
|
|
void
|
|
vfs_bio_bzero_buf(struct buf *bp, int base, int size)
|
|
{
|
|
vm_page_t m;
|
|
int i, n;
|
|
|
|
if (buf_mapped(bp)) {
|
|
BUF_CHECK_MAPPED(bp);
|
|
bzero(bp->b_data + base, size);
|
|
} else {
|
|
BUF_CHECK_UNMAPPED(bp);
|
|
n = PAGE_SIZE - (base & PAGE_MASK);
|
|
for (i = base / PAGE_SIZE; size > 0 && i < bp->b_npages; ++i) {
|
|
m = bp->b_pages[i];
|
|
if (n > size)
|
|
n = size;
|
|
pmap_zero_page_area(m, base & PAGE_MASK, n);
|
|
base += n;
|
|
size -= n;
|
|
n = PAGE_SIZE;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_hold_load_pages and vm_hold_free_pages get pages into
|
|
* a buffers address space. The pages are anonymous and are
|
|
* not associated with a file object.
|
|
*/
|
|
static void
|
|
vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to)
|
|
{
|
|
vm_offset_t pg;
|
|
vm_page_t p;
|
|
int index;
|
|
|
|
BUF_CHECK_MAPPED(bp);
|
|
|
|
to = round_page(to);
|
|
from = round_page(from);
|
|
index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT;
|
|
|
|
for (pg = from; pg < to; pg += PAGE_SIZE, index++) {
|
|
tryagain:
|
|
/*
|
|
* note: must allocate system pages since blocking here
|
|
* could interfere with paging I/O, no matter which
|
|
* process we are.
|
|
*/
|
|
p = vm_page_alloc(NULL, 0, VM_ALLOC_SYSTEM | VM_ALLOC_NOOBJ |
|
|
VM_ALLOC_WIRED | VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT));
|
|
if (p == NULL) {
|
|
VM_WAIT;
|
|
goto tryagain;
|
|
}
|
|
pmap_qenter(pg, &p, 1);
|
|
bp->b_pages[index] = p;
|
|
}
|
|
bp->b_npages = index;
|
|
}
|
|
|
|
/* Return pages associated with this buf to the vm system */
|
|
static void
|
|
vm_hold_free_pages(struct buf *bp, int newbsize)
|
|
{
|
|
vm_offset_t from;
|
|
vm_page_t p;
|
|
int index, newnpages;
|
|
|
|
BUF_CHECK_MAPPED(bp);
|
|
|
|
from = round_page((vm_offset_t)bp->b_data + newbsize);
|
|
newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT;
|
|
if (bp->b_npages > newnpages)
|
|
pmap_qremove(from, bp->b_npages - newnpages);
|
|
for (index = newnpages; index < bp->b_npages; index++) {
|
|
p = bp->b_pages[index];
|
|
bp->b_pages[index] = NULL;
|
|
if (vm_page_sbusied(p))
|
|
printf("vm_hold_free_pages: blkno: %jd, lblkno: %jd\n",
|
|
(intmax_t)bp->b_blkno, (intmax_t)bp->b_lblkno);
|
|
p->wire_count--;
|
|
vm_page_free(p);
|
|
atomic_subtract_int(&vm_cnt.v_wire_count, 1);
|
|
}
|
|
bp->b_npages = newnpages;
|
|
}
|
|
|
|
/*
|
|
* Map an IO request into kernel virtual address space.
|
|
*
|
|
* All requests are (re)mapped into kernel VA space.
|
|
* Notice that we use b_bufsize for the size of the buffer
|
|
* to be mapped. b_bcount might be modified by the driver.
|
|
*
|
|
* Note that even if the caller determines that the address space should
|
|
* be valid, a race or a smaller-file mapped into a larger space may
|
|
* actually cause vmapbuf() to fail, so all callers of vmapbuf() MUST
|
|
* check the return value.
|
|
*
|
|
* This function only works with pager buffers.
|
|
*/
|
|
int
|
|
vmapbuf(struct buf *bp, int mapbuf)
|
|
{
|
|
vm_prot_t prot;
|
|
int pidx;
|
|
|
|
if (bp->b_bufsize < 0)
|
|
return (-1);
|
|
prot = VM_PROT_READ;
|
|
if (bp->b_iocmd == BIO_READ)
|
|
prot |= VM_PROT_WRITE; /* Less backwards than it looks */
|
|
if ((pidx = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map,
|
|
(vm_offset_t)bp->b_data, bp->b_bufsize, prot, bp->b_pages,
|
|
btoc(MAXPHYS))) < 0)
|
|
return (-1);
|
|
bp->b_npages = pidx;
|
|
bp->b_offset = ((vm_offset_t)bp->b_data) & PAGE_MASK;
|
|
if (mapbuf || !unmapped_buf_allowed) {
|
|
pmap_qenter((vm_offset_t)bp->b_kvabase, bp->b_pages, pidx);
|
|
bp->b_data = bp->b_kvabase + bp->b_offset;
|
|
} else
|
|
bp->b_data = unmapped_buf;
|
|
return(0);
|
|
}
|
|
|
|
/*
|
|
* Free the io map PTEs associated with this IO operation.
|
|
* We also invalidate the TLB entries and restore the original b_addr.
|
|
*
|
|
* This function only works with pager buffers.
|
|
*/
|
|
void
|
|
vunmapbuf(struct buf *bp)
|
|
{
|
|
int npages;
|
|
|
|
npages = bp->b_npages;
|
|
if (buf_mapped(bp))
|
|
pmap_qremove(trunc_page((vm_offset_t)bp->b_data), npages);
|
|
vm_page_unhold_pages(bp->b_pages, npages);
|
|
|
|
bp->b_data = unmapped_buf;
|
|
}
|
|
|
|
void
|
|
bdone(struct buf *bp)
|
|
{
|
|
struct mtx *mtxp;
|
|
|
|
mtxp = mtx_pool_find(mtxpool_sleep, bp);
|
|
mtx_lock(mtxp);
|
|
bp->b_flags |= B_DONE;
|
|
wakeup(bp);
|
|
mtx_unlock(mtxp);
|
|
}
|
|
|
|
void
|
|
bwait(struct buf *bp, u_char pri, const char *wchan)
|
|
{
|
|
struct mtx *mtxp;
|
|
|
|
mtxp = mtx_pool_find(mtxpool_sleep, bp);
|
|
mtx_lock(mtxp);
|
|
while ((bp->b_flags & B_DONE) == 0)
|
|
msleep(bp, mtxp, pri, wchan, 0);
|
|
mtx_unlock(mtxp);
|
|
}
|
|
|
|
int
|
|
bufsync(struct bufobj *bo, int waitfor)
|
|
{
|
|
|
|
return (VOP_FSYNC(bo2vnode(bo), waitfor, curthread));
|
|
}
|
|
|
|
void
|
|
bufstrategy(struct bufobj *bo, struct buf *bp)
|
|
{
|
|
int i = 0;
|
|
struct vnode *vp;
|
|
|
|
vp = bp->b_vp;
|
|
KASSERT(vp == bo->bo_private, ("Inconsistent vnode bufstrategy"));
|
|
KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
|
|
("Wrong vnode in bufstrategy(bp=%p, vp=%p)", bp, vp));
|
|
i = VOP_STRATEGY(vp, bp);
|
|
KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp));
|
|
}
|
|
|
|
void
|
|
bufobj_wrefl(struct bufobj *bo)
|
|
{
|
|
|
|
KASSERT(bo != NULL, ("NULL bo in bufobj_wref"));
|
|
ASSERT_BO_WLOCKED(bo);
|
|
bo->bo_numoutput++;
|
|
}
|
|
|
|
void
|
|
bufobj_wref(struct bufobj *bo)
|
|
{
|
|
|
|
KASSERT(bo != NULL, ("NULL bo in bufobj_wref"));
|
|
BO_LOCK(bo);
|
|
bo->bo_numoutput++;
|
|
BO_UNLOCK(bo);
|
|
}
|
|
|
|
void
|
|
bufobj_wdrop(struct bufobj *bo)
|
|
{
|
|
|
|
KASSERT(bo != NULL, ("NULL bo in bufobj_wdrop"));
|
|
BO_LOCK(bo);
|
|
KASSERT(bo->bo_numoutput > 0, ("bufobj_wdrop non-positive count"));
|
|
if ((--bo->bo_numoutput == 0) && (bo->bo_flag & BO_WWAIT)) {
|
|
bo->bo_flag &= ~BO_WWAIT;
|
|
wakeup(&bo->bo_numoutput);
|
|
}
|
|
BO_UNLOCK(bo);
|
|
}
|
|
|
|
int
|
|
bufobj_wwait(struct bufobj *bo, int slpflag, int timeo)
|
|
{
|
|
int error;
|
|
|
|
KASSERT(bo != NULL, ("NULL bo in bufobj_wwait"));
|
|
ASSERT_BO_WLOCKED(bo);
|
|
error = 0;
|
|
while (bo->bo_numoutput) {
|
|
bo->bo_flag |= BO_WWAIT;
|
|
error = msleep(&bo->bo_numoutput, BO_LOCKPTR(bo),
|
|
slpflag | (PRIBIO + 1), "bo_wwait", timeo);
|
|
if (error)
|
|
break;
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Set bio_data or bio_ma for struct bio from the struct buf.
|
|
*/
|
|
void
|
|
bdata2bio(struct buf *bp, struct bio *bip)
|
|
{
|
|
|
|
if (!buf_mapped(bp)) {
|
|
KASSERT(unmapped_buf_allowed, ("unmapped"));
|
|
bip->bio_ma = bp->b_pages;
|
|
bip->bio_ma_n = bp->b_npages;
|
|
bip->bio_data = unmapped_buf;
|
|
bip->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK;
|
|
bip->bio_flags |= BIO_UNMAPPED;
|
|
KASSERT(round_page(bip->bio_ma_offset + bip->bio_length) /
|
|
PAGE_SIZE == bp->b_npages,
|
|
("Buffer %p too short: %d %lld %d", bp, bip->bio_ma_offset,
|
|
(long long)bip->bio_length, bip->bio_ma_n));
|
|
} else {
|
|
bip->bio_data = bp->b_data;
|
|
bip->bio_ma = NULL;
|
|
}
|
|
}
|
|
|
|
#include "opt_ddb.h"
|
|
#ifdef DDB
|
|
#include <ddb/ddb.h>
|
|
|
|
/* DDB command to show buffer data */
|
|
DB_SHOW_COMMAND(buffer, db_show_buffer)
|
|
{
|
|
/* get args */
|
|
struct buf *bp = (struct buf *)addr;
|
|
|
|
if (!have_addr) {
|
|
db_printf("usage: show buffer <addr>\n");
|
|
return;
|
|
}
|
|
|
|
db_printf("buf at %p\n", bp);
|
|
db_printf("b_flags = 0x%b, b_xflags=0x%b, b_vflags=0x%b\n",
|
|
(u_int)bp->b_flags, PRINT_BUF_FLAGS, (u_int)bp->b_xflags,
|
|
PRINT_BUF_XFLAGS, (u_int)bp->b_vflags, PRINT_BUF_VFLAGS);
|
|
db_printf(
|
|
"b_error = %d, b_bufsize = %ld, b_bcount = %ld, b_resid = %ld\n"
|
|
"b_bufobj = (%p), b_data = %p, b_blkno = %jd, b_lblkno = %jd, "
|
|
"b_dep = %p\n",
|
|
bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid,
|
|
bp->b_bufobj, bp->b_data, (intmax_t)bp->b_blkno,
|
|
(intmax_t)bp->b_lblkno, bp->b_dep.lh_first);
|
|
db_printf("b_kvabase = %p, b_kvasize = %d\n",
|
|
bp->b_kvabase, bp->b_kvasize);
|
|
if (bp->b_npages) {
|
|
int i;
|
|
db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
vm_page_t m;
|
|
m = bp->b_pages[i];
|
|
if (m != NULL)
|
|
db_printf("(%p, 0x%lx, 0x%lx)", m->object,
|
|
(u_long)m->pindex,
|
|
(u_long)VM_PAGE_TO_PHYS(m));
|
|
else
|
|
db_printf("( ??? )");
|
|
if ((i + 1) < bp->b_npages)
|
|
db_printf(",");
|
|
}
|
|
db_printf("\n");
|
|
}
|
|
db_printf(" ");
|
|
BUF_LOCKPRINTINFO(bp);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(lockedbufs, lockedbufs)
|
|
{
|
|
struct buf *bp;
|
|
int i;
|
|
|
|
for (i = 0; i < nbuf; i++) {
|
|
bp = &buf[i];
|
|
if (BUF_ISLOCKED(bp)) {
|
|
db_show_buffer((uintptr_t)bp, 1, 0, NULL);
|
|
db_printf("\n");
|
|
}
|
|
}
|
|
}
|
|
|
|
DB_SHOW_COMMAND(vnodebufs, db_show_vnodebufs)
|
|
{
|
|
struct vnode *vp;
|
|
struct buf *bp;
|
|
|
|
if (!have_addr) {
|
|
db_printf("usage: show vnodebufs <addr>\n");
|
|
return;
|
|
}
|
|
vp = (struct vnode *)addr;
|
|
db_printf("Clean buffers:\n");
|
|
TAILQ_FOREACH(bp, &vp->v_bufobj.bo_clean.bv_hd, b_bobufs) {
|
|
db_show_buffer((uintptr_t)bp, 1, 0, NULL);
|
|
db_printf("\n");
|
|
}
|
|
db_printf("Dirty buffers:\n");
|
|
TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd, b_bobufs) {
|
|
db_show_buffer((uintptr_t)bp, 1, 0, NULL);
|
|
db_printf("\n");
|
|
}
|
|
}
|
|
|
|
DB_COMMAND(countfreebufs, db_coundfreebufs)
|
|
{
|
|
struct buf *bp;
|
|
int i, used = 0, nfree = 0;
|
|
|
|
if (have_addr) {
|
|
db_printf("usage: countfreebufs\n");
|
|
return;
|
|
}
|
|
|
|
for (i = 0; i < nbuf; i++) {
|
|
bp = &buf[i];
|
|
if (bp->b_qindex == QUEUE_EMPTY)
|
|
nfree++;
|
|
else
|
|
used++;
|
|
}
|
|
|
|
db_printf("Counted %d free, %d used (%d tot)\n", nfree, used,
|
|
nfree + used);
|
|
db_printf("numfreebuffers is %d\n", numfreebuffers);
|
|
}
|
|
#endif /* DDB */
|