402bcb9621
The heuristic for managment of memory backing the buffer cache was nice, but didn't work due to some architectural problems. Simplify and improve the algorithm.
1875 lines
45 KiB
C
1875 lines
45 KiB
C
/*
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* Copyright (c) 1994 John S. Dyson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice immediately at the beginning of the file, without modification,
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* 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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* 3. Absolutely no warranty of function or purpose is made by the author
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* John S. Dyson.
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* 4. This work was done expressly for inclusion into FreeBSD. Other use
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* is allowed if this notation is included.
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* 5. Modifications may be freely made to this file if the above conditions
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* are met.
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*
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* $Id: vfs_bio.c,v 1.103 1996/10/06 07:50:05 dyson Exp $
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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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#include "opt_bounce.h"
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#define VMIO
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/vmmeter.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_prot.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 <sys/buf.h>
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#include <sys/mount.h>
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#include <sys/malloc.h>
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#include <sys/resourcevar.h>
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#include <sys/proc.h>
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#include <miscfs/specfs/specdev.h>
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static void vfs_update __P((void));
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static struct proc *updateproc;
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static struct kproc_desc up_kp = {
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"update",
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vfs_update,
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&updateproc
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};
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SYSINIT_KT(update, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp)
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struct buf *buf; /* buffer header pool */
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struct swqueue bswlist;
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int count_lock_queue __P((void));
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static void vm_hold_free_pages(struct buf * bp, vm_offset_t from,
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vm_offset_t to);
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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_clean_pages(struct buf * bp);
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static void vfs_setdirty(struct buf *bp);
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static void vfs_vmio_release(struct buf *bp);
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int needsbuffer;
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/*
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* Internal update daemon, process 3
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* The variable vfs_update_wakeup allows for internal syncs.
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*/
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int vfs_update_wakeup;
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|
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/*
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* buffers base kva
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*/
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caddr_t buffers_kva;
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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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static vm_offset_t bogus_offset;
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static int bufspace, maxbufspace, vmiospace, maxvmiobufspace,
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bufmallocspace, maxbufmallocspace;
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static struct bufhashhdr bufhashtbl[BUFHSZ], invalhash;
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static struct bqueues bufqueues[BUFFER_QUEUES];
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extern int vm_swap_size;
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#define BUF_MAXUSE 16
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/*
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* Initialize buffer headers and related structures.
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*/
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void
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bufinit()
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{
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struct buf *bp;
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int i;
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TAILQ_INIT(&bswlist);
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LIST_INIT(&invalhash);
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/* first, make a null hash table */
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for (i = 0; i < BUFHSZ; i++)
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LIST_INIT(&bufhashtbl[i]);
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/* next, make a null set of free lists */
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for (i = 0; i < BUFFER_QUEUES; i++)
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TAILQ_INIT(&bufqueues[i]);
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buffers_kva = (caddr_t) kmem_alloc_pageable(buffer_map, MAXBSIZE * nbuf);
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/* finally, initialize each buffer header and stick on empty q */
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for (i = 0; i < nbuf; i++) {
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bp = &buf[i];
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bzero(bp, sizeof *bp);
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bp->b_flags = B_INVAL; /* we're just an empty header */
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bp->b_dev = NODEV;
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bp->b_rcred = NOCRED;
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bp->b_wcred = NOCRED;
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bp->b_qindex = QUEUE_EMPTY;
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bp->b_vnbufs.le_next = NOLIST;
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bp->b_data = buffers_kva + i * MAXBSIZE;
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TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
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LIST_INSERT_HEAD(&invalhash, bp, b_hash);
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}
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/*
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* maxbufspace is currently calculated to support all filesystem blocks
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* to be 8K. If you happen to use a 16K filesystem, the size of the buffer
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* cache is still the same as it would be for 8K filesystems. This
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* keeps the size of the buffer cache "in check" for big block filesystems.
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*/
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maxbufspace = 2 * (nbuf + 8) * PAGE_SIZE;
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/*
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* reserve 1/3 of the buffers for metadata (VDIR) which might not be VMIO'ed
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*/
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maxvmiobufspace = 2 * maxbufspace / 3;
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/*
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* Limit the amount of malloc memory since it is wired permanently into
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* the kernel space. Even though this is accounted for in the buffer
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* allocation, we don't want the malloced region to grow uncontrolled.
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* The malloc scheme improves memory utilization significantly on average
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* (small) directories.
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*/
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maxbufmallocspace = maxbufspace / 20;
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bogus_offset = kmem_alloc_pageable(kernel_map, PAGE_SIZE);
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bogus_page = vm_page_alloc(kernel_object,
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((bogus_offset - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT),
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VM_ALLOC_NORMAL);
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}
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/*
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* remove the buffer from the appropriate free list
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*/
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void
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bremfree(struct buf * bp)
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{
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int s = splbio();
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if (bp->b_qindex != QUEUE_NONE) {
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TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist);
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bp->b_qindex = QUEUE_NONE;
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} else {
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panic("bremfree: removing a buffer when not on a queue");
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}
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splx(s);
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}
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/*
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* Get a buffer with the specified data. Look in the cache first.
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*/
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int
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bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred,
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struct buf ** bpp)
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{
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struct buf *bp;
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bp = getblk(vp, blkno, size, 0, 0);
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*bpp = bp;
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/* if not found in cache, do some I/O */
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if ((bp->b_flags & B_CACHE) == 0) {
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if (curproc != NULL)
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curproc->p_stats->p_ru.ru_inblock++;
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bp->b_flags |= B_READ;
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bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL);
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if (bp->b_rcred == NOCRED) {
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if (cred != NOCRED)
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crhold(cred);
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bp->b_rcred = cred;
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}
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vfs_busy_pages(bp, 0);
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VOP_STRATEGY(bp);
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return (biowait(bp));
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}
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return (0);
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}
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/*
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* Operates like bread, but also starts asynchronous I/O on
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* read-ahead blocks.
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*/
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int
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breadn(struct vnode * vp, daddr_t blkno, int size,
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daddr_t * rablkno, int *rabsize,
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int cnt, struct ucred * cred, struct buf ** bpp)
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{
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struct buf *bp, *rabp;
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int i;
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int rv = 0, readwait = 0;
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*bpp = bp = getblk(vp, blkno, size, 0, 0);
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/* if not found in cache, do some I/O */
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if ((bp->b_flags & B_CACHE) == 0) {
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if (curproc != NULL)
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curproc->p_stats->p_ru.ru_inblock++;
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bp->b_flags |= B_READ;
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bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL);
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if (bp->b_rcred == NOCRED) {
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if (cred != NOCRED)
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crhold(cred);
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bp->b_rcred = cred;
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}
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vfs_busy_pages(bp, 0);
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VOP_STRATEGY(bp);
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++readwait;
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}
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for (i = 0; i < cnt; i++, rablkno++, rabsize++) {
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if (inmem(vp, *rablkno))
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continue;
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rabp = getblk(vp, *rablkno, *rabsize, 0, 0);
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if ((rabp->b_flags & B_CACHE) == 0) {
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if (curproc != NULL)
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curproc->p_stats->p_ru.ru_inblock++;
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rabp->b_flags |= B_READ | B_ASYNC;
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rabp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL);
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if (rabp->b_rcred == NOCRED) {
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if (cred != NOCRED)
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crhold(cred);
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rabp->b_rcred = cred;
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}
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vfs_busy_pages(rabp, 0);
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VOP_STRATEGY(rabp);
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} else {
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brelse(rabp);
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}
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}
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if (readwait) {
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rv = biowait(bp);
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}
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return (rv);
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}
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/*
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* Write, release buffer on completion. (Done by iodone
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* if async.)
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*/
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int
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bwrite(struct buf * bp)
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{
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int oldflags = bp->b_flags;
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if (bp->b_flags & B_INVAL) {
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brelse(bp);
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return (0);
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}
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if (!(bp->b_flags & B_BUSY))
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panic("bwrite: buffer is not busy???");
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bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
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bp->b_flags |= B_WRITEINPROG;
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if ((oldflags & (B_ASYNC|B_DELWRI)) == (B_ASYNC|B_DELWRI)) {
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reassignbuf(bp, bp->b_vp);
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}
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bp->b_vp->v_numoutput++;
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vfs_busy_pages(bp, 1);
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if (curproc != NULL)
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curproc->p_stats->p_ru.ru_oublock++;
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VOP_STRATEGY(bp);
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/*
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* Handle ordered writes here.
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* If the write was originally flagged as ordered,
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* then we check to see if it was converted to async.
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* If it was converted to async, and is done now, then
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* we release the buffer. Otherwise we clear the
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* ordered flag because it is not needed anymore.
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*
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* Note that biodone has been modified so that it does
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* not release ordered buffers. This allows us to have
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* a chance to determine whether or not the driver
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* has set the async flag in the strategy routine. Otherwise
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* if biodone was not modified, then the buffer may have been
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* reused before we have had a chance to check the flag.
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*/
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if ((oldflags & B_ORDERED) == B_ORDERED) {
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int s;
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s = splbio();
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if (bp->b_flags & B_ASYNC) {
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if ((bp->b_flags & B_DONE)) {
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if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0)
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brelse(bp);
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else
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bqrelse(bp);
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}
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splx(s);
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return (0);
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} else {
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bp->b_flags &= ~B_ORDERED;
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}
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splx(s);
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}
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if ((oldflags & B_ASYNC) == 0) {
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int rtval = biowait(bp);
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if (oldflags & B_DELWRI) {
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reassignbuf(bp, bp->b_vp);
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}
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brelse(bp);
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return (rtval);
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}
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return (0);
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}
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int
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vn_bwrite(ap)
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struct vop_bwrite_args *ap;
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{
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return (bwrite(ap->a_bp));
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}
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/*
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* Delayed write. (Buffer is marked dirty).
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*/
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void
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bdwrite(struct buf * bp)
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{
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if ((bp->b_flags & B_BUSY) == 0) {
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panic("bdwrite: buffer is not busy");
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}
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if (bp->b_flags & B_INVAL) {
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brelse(bp);
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return;
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}
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if (bp->b_flags & B_TAPE) {
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bawrite(bp);
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return;
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}
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bp->b_flags &= ~(B_READ|B_RELBUF);
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if ((bp->b_flags & B_DELWRI) == 0) {
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bp->b_flags |= B_DONE | B_DELWRI;
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reassignbuf(bp, bp->b_vp);
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}
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|
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/*
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* This bmap keeps the system from needing to do the bmap later,
|
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* perhaps when the system is attempting to do a sync. Since it
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* is likely that the indirect block -- or whatever other datastructure
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* that the filesystem needs is still in memory now, it is a good
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* thing to do this. Note also, that if the pageout daemon is
|
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* requesting a sync -- there might not be enough memory to do
|
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* the bmap then... So, this is important to do.
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*/
|
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if( bp->b_lblkno == bp->b_blkno) {
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VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL);
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}
|
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|
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/*
|
|
* Set the *dirty* buffer range based upon the VM system dirty pages.
|
|
*/
|
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vfs_setdirty(bp);
|
|
|
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/*
|
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* We need to do this here to satisfy the vnode_pager and the
|
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* pageout daemon, so that it thinks that the pages have been
|
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* "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(bp);
|
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bqrelse(bp);
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return;
|
|
}
|
|
|
|
/*
|
|
* Asynchronous write.
|
|
* Start output on a buffer, but do not wait for it to complete.
|
|
* The buffer is released when the output completes.
|
|
*/
|
|
void
|
|
bawrite(struct buf * bp)
|
|
{
|
|
bp->b_flags |= B_ASYNC;
|
|
(void) VOP_BWRITE(bp);
|
|
}
|
|
|
|
/*
|
|
* Ordered write.
|
|
* Start output on a buffer, but only wait for it to complete if the
|
|
* output device cannot guarantee ordering in some other way. Devices
|
|
* that can perform asynchronous ordered writes will set the B_ASYNC
|
|
* flag in their strategy routine.
|
|
* The buffer is released when the output completes.
|
|
*/
|
|
int
|
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bowrite(struct buf * bp)
|
|
{
|
|
bp->b_flags |= B_ORDERED;
|
|
return (VOP_BWRITE(bp));
|
|
}
|
|
|
|
/*
|
|
* Release a buffer.
|
|
*/
|
|
void
|
|
brelse(struct buf * bp)
|
|
{
|
|
int s;
|
|
|
|
if (bp->b_flags & B_CLUSTER) {
|
|
relpbuf(bp);
|
|
return;
|
|
}
|
|
/* anyone need a "free" block? */
|
|
s = splbio();
|
|
|
|
/* anyone need this block? */
|
|
if (bp->b_flags & B_WANTED) {
|
|
bp->b_flags &= ~(B_WANTED | B_AGE);
|
|
wakeup(bp);
|
|
}
|
|
|
|
if (bp->b_flags & B_LOCKED)
|
|
bp->b_flags &= ~B_ERROR;
|
|
|
|
if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR)) ||
|
|
(bp->b_bufsize <= 0)) {
|
|
bp->b_flags |= B_INVAL;
|
|
bp->b_flags &= ~(B_DELWRI | B_CACHE);
|
|
if (((bp->b_flags & B_VMIO) == 0) && bp->b_vp) {
|
|
if (bp->b_bufsize)
|
|
allocbuf(bp, 0);
|
|
brelvp(bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* VMIO buffer rundown. It is not very necessary to keep a VMIO buffer
|
|
* constituted, so the B_INVAL flag is used to *invalidate* the buffer,
|
|
* but the VM object is kept around. The B_NOCACHE flag is used to
|
|
* invalidate the pages in the VM object.
|
|
*/
|
|
if (bp->b_flags & B_VMIO) {
|
|
vm_ooffset_t foff;
|
|
vm_object_t obj;
|
|
int i, resid;
|
|
vm_page_t m;
|
|
struct vnode *vp;
|
|
int iototal = bp->b_bufsize;
|
|
|
|
vp = bp->b_vp;
|
|
if (!vp)
|
|
panic("brelse: missing vp");
|
|
|
|
if (bp->b_npages) {
|
|
vm_pindex_t poff;
|
|
obj = (vm_object_t) vp->v_object;
|
|
if (vp->v_type == VBLK)
|
|
foff = ((vm_ooffset_t) bp->b_lblkno) << DEV_BSHIFT;
|
|
else
|
|
foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno;
|
|
poff = OFF_TO_IDX(foff);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
if (m == bogus_page) {
|
|
m = vm_page_lookup(obj, poff + i);
|
|
if (!m) {
|
|
panic("brelse: page missing\n");
|
|
}
|
|
bp->b_pages[i] = m;
|
|
pmap_qenter(trunc_page(bp->b_data),
|
|
bp->b_pages, bp->b_npages);
|
|
}
|
|
resid = IDX_TO_OFF(m->pindex+1) - foff;
|
|
if (resid > iototal)
|
|
resid = iototal;
|
|
if (resid > 0) {
|
|
/*
|
|
* Don't invalidate the page if the local machine has already
|
|
* modified it. This is the lesser of two evils, and should
|
|
* be fixed.
|
|
*/
|
|
if (bp->b_flags & (B_NOCACHE | B_ERROR)) {
|
|
vm_page_test_dirty(m);
|
|
if (m->dirty == 0) {
|
|
vm_page_set_invalid(m, (vm_offset_t) foff, resid);
|
|
if (m->valid == 0)
|
|
vm_page_protect(m, VM_PROT_NONE);
|
|
}
|
|
}
|
|
if (resid >= PAGE_SIZE) {
|
|
if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
|
|
bp->b_flags |= B_INVAL;
|
|
}
|
|
} else {
|
|
if (!vm_page_is_valid(m,
|
|
(((vm_offset_t) bp->b_data) & PAGE_MASK), resid)) {
|
|
bp->b_flags |= B_INVAL;
|
|
}
|
|
}
|
|
}
|
|
foff += resid;
|
|
iototal -= resid;
|
|
}
|
|
}
|
|
if (bp->b_flags & (B_INVAL | B_RELBUF))
|
|
vfs_vmio_release(bp);
|
|
}
|
|
if (bp->b_qindex != QUEUE_NONE)
|
|
panic("brelse: free buffer onto another queue???");
|
|
|
|
/* enqueue */
|
|
/* buffers with no memory */
|
|
if (bp->b_bufsize == 0) {
|
|
bp->b_qindex = QUEUE_EMPTY;
|
|
TAILQ_INSERT_HEAD(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
|
|
LIST_REMOVE(bp, b_hash);
|
|
LIST_INSERT_HEAD(&invalhash, bp, b_hash);
|
|
bp->b_dev = NODEV;
|
|
if (needsbuffer) {
|
|
wakeup(&needsbuffer);
|
|
needsbuffer=0;
|
|
}
|
|
/* buffers with junk contents */
|
|
} else if (bp->b_flags & (B_ERROR | B_INVAL | B_NOCACHE | B_RELBUF)) {
|
|
bp->b_qindex = QUEUE_AGE;
|
|
TAILQ_INSERT_HEAD(&bufqueues[QUEUE_AGE], bp, b_freelist);
|
|
LIST_REMOVE(bp, b_hash);
|
|
LIST_INSERT_HEAD(&invalhash, bp, b_hash);
|
|
bp->b_dev = NODEV;
|
|
if (needsbuffer) {
|
|
wakeup(&needsbuffer);
|
|
needsbuffer=0;
|
|
}
|
|
/* buffers that are locked */
|
|
} else if (bp->b_flags & B_LOCKED) {
|
|
bp->b_qindex = QUEUE_LOCKED;
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist);
|
|
/* buffers with stale but valid contents */
|
|
} else if (bp->b_flags & B_AGE) {
|
|
bp->b_qindex = QUEUE_AGE;
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_AGE], bp, b_freelist);
|
|
if (needsbuffer) {
|
|
wakeup(&needsbuffer);
|
|
needsbuffer=0;
|
|
}
|
|
/* buffers with valid and quite potentially reuseable contents */
|
|
} else {
|
|
bp->b_qindex = QUEUE_LRU;
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist);
|
|
if (needsbuffer) {
|
|
wakeup(&needsbuffer);
|
|
needsbuffer=0;
|
|
}
|
|
}
|
|
|
|
/* unlock */
|
|
bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY |
|
|
B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* Release a buffer.
|
|
*/
|
|
void
|
|
bqrelse(struct buf * bp)
|
|
{
|
|
int s;
|
|
|
|
s = splbio();
|
|
|
|
|
|
/* anyone need this block? */
|
|
if (bp->b_flags & B_WANTED) {
|
|
bp->b_flags &= ~(B_WANTED | B_AGE);
|
|
wakeup(bp);
|
|
}
|
|
|
|
if (bp->b_qindex != QUEUE_NONE)
|
|
panic("bqrelse: free buffer onto another queue???");
|
|
|
|
if (bp->b_flags & B_LOCKED) {
|
|
bp->b_flags &= ~B_ERROR;
|
|
bp->b_qindex = QUEUE_LOCKED;
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist);
|
|
/* buffers with stale but valid contents */
|
|
} else {
|
|
bp->b_qindex = QUEUE_LRU;
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist);
|
|
if (needsbuffer) {
|
|
wakeup(&needsbuffer);
|
|
needsbuffer=0;
|
|
}
|
|
}
|
|
|
|
/* unlock */
|
|
bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY |
|
|
B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF);
|
|
splx(s);
|
|
}
|
|
|
|
static void
|
|
vfs_vmio_release(bp)
|
|
struct buf *bp;
|
|
{
|
|
int i;
|
|
vm_page_t m;
|
|
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
m = bp->b_pages[i];
|
|
bp->b_pages[i] = NULL;
|
|
vm_page_unwire(m);
|
|
/*
|
|
* We don't mess with busy pages, it is
|
|
* the responsibility of the process that
|
|
* busied the pages to deal with them.
|
|
*/
|
|
if ((m->flags & PG_BUSY) || (m->busy != 0))
|
|
continue;
|
|
|
|
if (m->wire_count == 0) {
|
|
|
|
if (m->flags & PG_WANTED) {
|
|
m->flags &= ~PG_WANTED;
|
|
wakeup(m);
|
|
}
|
|
|
|
/*
|
|
* If this is an async free -- we cannot place
|
|
* pages onto the cache queue, so our policy for
|
|
* such buffers is to avoid the cache queue, and
|
|
* only modify the active queue or free queue.
|
|
*/
|
|
if ((bp->b_flags & B_ASYNC) == 0) {
|
|
|
|
/*
|
|
* In the case of sync buffer frees, we can do pretty much
|
|
* anything to any of the memory queues. Specifically,
|
|
* the cache queue is free to be modified.
|
|
*/
|
|
if (m->valid) {
|
|
if(m->dirty == 0)
|
|
vm_page_test_dirty(m);
|
|
/*
|
|
* this keeps pressure off of the process memory
|
|
*/
|
|
if ((vm_swap_size == 0) ||
|
|
(cnt.v_free_count < cnt.v_free_min)) {
|
|
if ((m->dirty == 0) &&
|
|
(m->hold_count == 0))
|
|
vm_page_cache(m);
|
|
else
|
|
vm_page_deactivate(m);
|
|
}
|
|
} else if (m->hold_count == 0) {
|
|
vm_page_protect(m, VM_PROT_NONE);
|
|
vm_page_free(m);
|
|
}
|
|
} else {
|
|
/*
|
|
* If async, then at least we clear the
|
|
* act_count.
|
|
*/
|
|
m->act_count = 0;
|
|
}
|
|
}
|
|
}
|
|
bufspace -= bp->b_bufsize;
|
|
vmiospace -= bp->b_bufsize;
|
|
pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages);
|
|
bp->b_npages = 0;
|
|
bp->b_bufsize = 0;
|
|
bp->b_flags &= ~B_VMIO;
|
|
if (bp->b_vp)
|
|
brelvp(bp);
|
|
}
|
|
|
|
/*
|
|
* Check to see if a block is currently memory resident.
|
|
*/
|
|
__inline struct buf *
|
|
gbincore(struct vnode * vp, daddr_t blkno)
|
|
{
|
|
struct buf *bp;
|
|
struct bufhashhdr *bh;
|
|
|
|
bh = BUFHASH(vp, blkno);
|
|
bp = bh->lh_first;
|
|
|
|
/* Search hash chain */
|
|
while (bp != NULL) {
|
|
/* hit */
|
|
if (bp->b_vp == vp && bp->b_lblkno == blkno &&
|
|
(bp->b_flags & B_INVAL) == 0) {
|
|
break;
|
|
}
|
|
bp = bp->b_hash.le_next;
|
|
}
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* this routine implements clustered async writes for
|
|
* clearing out B_DELWRI buffers... This is much better
|
|
* than the old way of writing only one buffer at a time.
|
|
*/
|
|
int
|
|
vfs_bio_awrite(struct buf * bp)
|
|
{
|
|
int i;
|
|
daddr_t lblkno = bp->b_lblkno;
|
|
struct vnode *vp = bp->b_vp;
|
|
int s;
|
|
int ncl;
|
|
struct buf *bpa;
|
|
int nwritten;
|
|
|
|
s = splbio();
|
|
/*
|
|
* right now we support clustered writing only to regular files
|
|
*/
|
|
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) {
|
|
int size;
|
|
int maxcl;
|
|
|
|
size = vp->v_mount->mnt_stat.f_iosize;
|
|
maxcl = MAXPHYS / size;
|
|
|
|
for (i = 1; i < maxcl; i++) {
|
|
if ((bpa = gbincore(vp, lblkno + i)) &&
|
|
((bpa->b_flags & (B_BUSY | B_DELWRI | B_CLUSTEROK | B_INVAL)) ==
|
|
(B_DELWRI | B_CLUSTEROK)) &&
|
|
(bpa->b_bufsize == size)) {
|
|
if ((bpa->b_blkno == bpa->b_lblkno) ||
|
|
(bpa->b_blkno != bp->b_blkno + ((i * size) >> DEV_BSHIFT)))
|
|
break;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
ncl = i;
|
|
/*
|
|
* this is a possible cluster write
|
|
*/
|
|
if (ncl != 1) {
|
|
nwritten = cluster_wbuild(vp, size, lblkno, ncl);
|
|
splx(s);
|
|
return nwritten;
|
|
}
|
|
}
|
|
bremfree(bp);
|
|
splx(s);
|
|
/*
|
|
* default (old) behavior, writing out only one block
|
|
*/
|
|
bp->b_flags |= B_BUSY | B_ASYNC;
|
|
nwritten = bp->b_bufsize;
|
|
(void) VOP_BWRITE(bp);
|
|
return nwritten;
|
|
}
|
|
|
|
|
|
/*
|
|
* Find a buffer header which is available for use.
|
|
*/
|
|
static struct buf *
|
|
getnewbuf(int slpflag, int slptimeo, int doingvmio)
|
|
{
|
|
struct buf *bp;
|
|
int nbyteswritten = 0;
|
|
|
|
start:
|
|
if (bufspace >= maxbufspace)
|
|
goto trytofreespace;
|
|
|
|
/* can we constitute a new buffer? */
|
|
if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]))) {
|
|
if (bp->b_qindex != QUEUE_EMPTY)
|
|
panic("getnewbuf: inconsistent EMPTY queue, qindex=%d",
|
|
bp->b_qindex);
|
|
bp->b_flags |= B_BUSY;
|
|
bremfree(bp);
|
|
goto fillbuf;
|
|
}
|
|
trytofreespace:
|
|
/*
|
|
* We keep the file I/O from hogging metadata I/O
|
|
* This is desirable because file data is cached in the
|
|
* VM/Buffer cache even if a buffer is freed.
|
|
*/
|
|
if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]))) {
|
|
if (bp->b_qindex != QUEUE_AGE)
|
|
panic("getnewbuf: inconsistent AGE queue, qindex=%d",
|
|
bp->b_qindex);
|
|
} else if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]))) {
|
|
if (bp->b_qindex != QUEUE_LRU)
|
|
panic("getnewbuf: inconsistent LRU queue, qindex=%d",
|
|
bp->b_qindex);
|
|
}
|
|
if (!bp) {
|
|
/* wait for a free buffer of any kind */
|
|
needsbuffer = 1;
|
|
tsleep(&needsbuffer,
|
|
(PRIBIO + 1) | slpflag, "newbuf", slptimeo);
|
|
return (0);
|
|
}
|
|
|
|
#if defined(DIAGNOSTIC)
|
|
if (bp->b_flags & B_BUSY) {
|
|
panic("getnewbuf: busy buffer on free list\n");
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* We are fairly aggressive about freeing VMIO buffers, but since
|
|
* the buffering is intact without buffer headers, there is not
|
|
* much loss. We gain by maintaining non-VMIOed metadata in buffers.
|
|
*/
|
|
if ((bp->b_qindex == QUEUE_LRU) && (bp->b_usecount > 0)) {
|
|
if ((bp->b_flags & B_VMIO) == 0 ||
|
|
(vmiospace < maxvmiobufspace)) {
|
|
--bp->b_usecount;
|
|
TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist);
|
|
if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) {
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist);
|
|
goto start;
|
|
}
|
|
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist);
|
|
}
|
|
}
|
|
|
|
/* if we are a delayed write, convert to an async write */
|
|
if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) {
|
|
nbyteswritten += vfs_bio_awrite(bp);
|
|
if (!slpflag && !slptimeo) {
|
|
return (0);
|
|
}
|
|
goto start;
|
|
}
|
|
|
|
if (bp->b_flags & B_WANTED) {
|
|
bp->b_flags &= ~B_WANTED;
|
|
wakeup(bp);
|
|
}
|
|
bremfree(bp);
|
|
bp->b_flags |= B_BUSY;
|
|
|
|
if (bp->b_flags & B_VMIO) {
|
|
bp->b_flags &= ~B_ASYNC;
|
|
vfs_vmio_release(bp);
|
|
}
|
|
|
|
if (bp->b_vp)
|
|
brelvp(bp);
|
|
|
|
fillbuf:
|
|
/* we are not free, nor do we contain interesting data */
|
|
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;
|
|
}
|
|
|
|
LIST_REMOVE(bp, b_hash);
|
|
LIST_INSERT_HEAD(&invalhash, bp, b_hash);
|
|
if (bp->b_bufsize) {
|
|
allocbuf(bp, 0);
|
|
}
|
|
bp->b_flags = B_BUSY;
|
|
bp->b_dev = NODEV;
|
|
bp->b_vp = NULL;
|
|
bp->b_blkno = bp->b_lblkno = 0;
|
|
bp->b_iodone = 0;
|
|
bp->b_error = 0;
|
|
bp->b_resid = 0;
|
|
bp->b_bcount = 0;
|
|
bp->b_npages = 0;
|
|
bp->b_data = buffers_kva + (bp - buf) * MAXBSIZE;
|
|
bp->b_dirtyoff = bp->b_dirtyend = 0;
|
|
bp->b_validoff = bp->b_validend = 0;
|
|
bp->b_usecount = 4;
|
|
if (bufspace >= maxbufspace + nbyteswritten) {
|
|
bp->b_flags |= B_INVAL;
|
|
brelse(bp);
|
|
goto trytofreespace;
|
|
}
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Check to see if a block is currently memory resident.
|
|
*/
|
|
struct buf *
|
|
incore(struct vnode * vp, daddr_t blkno)
|
|
{
|
|
struct buf *bp;
|
|
|
|
int s = splbio();
|
|
bp = gbincore(vp, blkno);
|
|
splx(s);
|
|
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.
|
|
*/
|
|
|
|
int
|
|
inmem(struct vnode * vp, daddr_t blkno)
|
|
{
|
|
vm_object_t obj;
|
|
vm_offset_t toff, tinc;
|
|
vm_page_t m;
|
|
vm_ooffset_t off;
|
|
|
|
if (incore(vp, blkno))
|
|
return 1;
|
|
if (vp->v_mount == NULL)
|
|
return 0;
|
|
if ((vp->v_object == NULL) || (vp->v_flag & VVMIO) == 0)
|
|
return 0;
|
|
|
|
obj = vp->v_object;
|
|
tinc = PAGE_SIZE;
|
|
if (tinc > vp->v_mount->mnt_stat.f_iosize)
|
|
tinc = vp->v_mount->mnt_stat.f_iosize;
|
|
off = blkno * vp->v_mount->mnt_stat.f_iosize;
|
|
|
|
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)
|
|
return 0;
|
|
if (vm_page_is_valid(m, (vm_offset_t) (toff + off), tinc) == 0)
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* now we set the dirty range for the buffer --
|
|
* for NFS -- if the file is mapped and pages have
|
|
* been written to, let it know. We want the
|
|
* entire range of the buffer to be marked dirty if
|
|
* any of the pages have been written to for consistancy
|
|
* with the b_validoff, b_validend set in the nfs write
|
|
* code, and used by the nfs read code.
|
|
*/
|
|
static void
|
|
vfs_setdirty(struct buf *bp) {
|
|
int i;
|
|
vm_object_t object;
|
|
vm_offset_t boffset, offset;
|
|
/*
|
|
* We qualify the scan for modified pages on whether the
|
|
* object has been flushed yet. The OBJ_WRITEABLE flag
|
|
* is not cleared simply by protecting pages off.
|
|
*/
|
|
if ((bp->b_flags & B_VMIO) &&
|
|
((object = bp->b_pages[0]->object)->flags & (OBJ_WRITEABLE|OBJ_CLEANING))) {
|
|
/*
|
|
* 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]);
|
|
|
|
/*
|
|
* scan forwards for the first page modified
|
|
*/
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
if (bp->b_pages[i]->dirty) {
|
|
break;
|
|
}
|
|
}
|
|
boffset = (i << PAGE_SHIFT);
|
|
if (boffset < bp->b_dirtyoff) {
|
|
bp->b_dirtyoff = boffset;
|
|
}
|
|
|
|
/*
|
|
* scan backwards for the last page modified
|
|
*/
|
|
for (i = bp->b_npages - 1; i >= 0; --i) {
|
|
if (bp->b_pages[i]->dirty) {
|
|
break;
|
|
}
|
|
}
|
|
boffset = (i + 1);
|
|
offset = boffset + bp->b_pages[0]->pindex;
|
|
if (offset >= object->size)
|
|
boffset = object->size - bp->b_pages[0]->pindex;
|
|
if (bp->b_dirtyend < (boffset << PAGE_SHIFT))
|
|
bp->b_dirtyend = (boffset << PAGE_SHIFT);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get a block given a specified block and offset into a file/device.
|
|
*/
|
|
struct buf *
|
|
getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo)
|
|
{
|
|
struct buf *bp;
|
|
int s;
|
|
struct bufhashhdr *bh;
|
|
|
|
s = splbio();
|
|
loop:
|
|
if ((bp = gbincore(vp, blkno))) {
|
|
if (bp->b_flags & B_BUSY) {
|
|
bp->b_flags |= B_WANTED;
|
|
if (bp->b_usecount < BUF_MAXUSE)
|
|
++bp->b_usecount;
|
|
if (!tsleep(bp,
|
|
(PRIBIO + 1) | slpflag, "getblk", slptimeo))
|
|
goto loop;
|
|
|
|
splx(s);
|
|
return (struct buf *) NULL;
|
|
}
|
|
bp->b_flags |= B_BUSY | B_CACHE;
|
|
bremfree(bp);
|
|
|
|
/*
|
|
* check for size inconsistancies (note that they shouldn't happen
|
|
* but do when filesystems don't handle the size changes correctly.)
|
|
* We are conservative on metadata and don't just extend the buffer
|
|
* but write and re-constitute it.
|
|
*/
|
|
|
|
if (bp->b_bcount != size) {
|
|
if (bp->b_flags & B_VMIO) {
|
|
allocbuf(bp, size);
|
|
} else {
|
|
bp->b_flags |= B_NOCACHE;
|
|
VOP_BWRITE(bp);
|
|
goto loop;
|
|
}
|
|
}
|
|
|
|
if (bp->b_usecount < BUF_MAXUSE)
|
|
++bp->b_usecount;
|
|
splx(s);
|
|
return (bp);
|
|
} else {
|
|
vm_object_t obj;
|
|
int doingvmio;
|
|
|
|
if ((obj = vp->v_object) && (vp->v_flag & VVMIO)) {
|
|
doingvmio = 1;
|
|
} else {
|
|
doingvmio = 0;
|
|
}
|
|
if ((bp = getnewbuf(slpflag, slptimeo, doingvmio)) == 0) {
|
|
if (slpflag || slptimeo) {
|
|
splx(s);
|
|
return NULL;
|
|
}
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* This code is used to make sure that a buffer is not
|
|
* created while the getnewbuf routine is blocked.
|
|
* Normally the vnode is locked so this isn't a problem.
|
|
* VBLK type I/O requests, however, don't lock the vnode.
|
|
*/
|
|
if (!VOP_ISLOCKED(vp) && gbincore(vp, blkno)) {
|
|
bp->b_flags |= B_INVAL;
|
|
brelse(bp);
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* Insert the buffer into the hash, so that it can
|
|
* be found by incore.
|
|
*/
|
|
bp->b_blkno = bp->b_lblkno = blkno;
|
|
bgetvp(vp, bp);
|
|
LIST_REMOVE(bp, b_hash);
|
|
bh = BUFHASH(vp, blkno);
|
|
LIST_INSERT_HEAD(bh, bp, b_hash);
|
|
|
|
if (doingvmio) {
|
|
bp->b_flags |= (B_VMIO | B_CACHE);
|
|
#if defined(VFS_BIO_DEBUG)
|
|
if (vp->v_type != VREG && vp->v_type != VBLK)
|
|
printf("getblk: vmioing file type %d???\n", vp->v_type);
|
|
#endif
|
|
} else {
|
|
bp->b_flags &= ~B_VMIO;
|
|
}
|
|
splx(s);
|
|
|
|
allocbuf(bp, size);
|
|
#ifdef PC98
|
|
/*
|
|
* 1024byte/sector support
|
|
*/
|
|
#define B_XXX2 0x8000000
|
|
if (vp->v_flag & 0x10000) bp->b_flags |= B_XXX2;
|
|
#endif
|
|
return (bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get an empty, disassociated buffer of given size.
|
|
*/
|
|
struct buf *
|
|
geteblk(int size)
|
|
{
|
|
struct buf *bp;
|
|
int s;
|
|
|
|
s = splbio();
|
|
while ((bp = getnewbuf(0, 0, 0)) == 0);
|
|
splx(s);
|
|
allocbuf(bp, size);
|
|
bp->b_flags |= B_INVAL;
|
|
return (bp);
|
|
}
|
|
|
|
|
|
/*
|
|
* 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).
|
|
*
|
|
* Note that this code is tricky, and has many complications to resolve
|
|
* deadlock or inconsistant data situations. Tread lightly!!!
|
|
*
|
|
* Modify the length of a buffer's underlying buffer storage without
|
|
* destroying information (unless, of course the buffer is shrinking).
|
|
*/
|
|
int
|
|
allocbuf(struct buf * bp, int size)
|
|
{
|
|
|
|
int s;
|
|
int newbsize, mbsize;
|
|
int i;
|
|
|
|
if (!(bp->b_flags & B_BUSY))
|
|
panic("allocbuf: buffer not busy");
|
|
|
|
if ((bp->b_flags & B_VMIO) == 0) {
|
|
caddr_t origbuf;
|
|
int origbufsize;
|
|
/*
|
|
* Just get anonymous memory from the kernel
|
|
*/
|
|
mbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1);
|
|
#if !defined(NO_B_MALLOC)
|
|
if (bp->b_flags & B_MALLOC)
|
|
newbsize = mbsize;
|
|
else
|
|
#endif
|
|
newbsize = round_page(size);
|
|
|
|
if (newbsize < bp->b_bufsize) {
|
|
#if !defined(NO_B_MALLOC)
|
|
/*
|
|
* malloced buffers are not shrunk
|
|
*/
|
|
if (bp->b_flags & B_MALLOC) {
|
|
if (newbsize) {
|
|
bp->b_bcount = size;
|
|
} else {
|
|
free(bp->b_data, M_BIOBUF);
|
|
bufspace -= bp->b_bufsize;
|
|
bufmallocspace -= bp->b_bufsize;
|
|
bp->b_data = (caddr_t) buffers_kva + (bp - buf) * MAXBSIZE;
|
|
bp->b_bufsize = 0;
|
|
bp->b_bcount = 0;
|
|
bp->b_flags &= ~B_MALLOC;
|
|
}
|
|
return 1;
|
|
}
|
|
#endif
|
|
vm_hold_free_pages(
|
|
bp,
|
|
(vm_offset_t) bp->b_data + newbsize,
|
|
(vm_offset_t) bp->b_data + bp->b_bufsize);
|
|
} else if (newbsize > bp->b_bufsize) {
|
|
#if !defined(NO_B_MALLOC)
|
|
/*
|
|
* We only use malloced memory on the first allocation.
|
|
* and revert to page-allocated memory when the buffer grows.
|
|
*/
|
|
if ( (bufmallocspace < maxbufmallocspace) &&
|
|
(bp->b_bufsize == 0) &&
|
|
(mbsize <= PAGE_SIZE/2)) {
|
|
|
|
bp->b_data = malloc(mbsize, M_BIOBUF, M_WAITOK);
|
|
bp->b_bufsize = mbsize;
|
|
bp->b_bcount = size;
|
|
bp->b_flags |= B_MALLOC;
|
|
bufspace += mbsize;
|
|
bufmallocspace += mbsize;
|
|
return 1;
|
|
}
|
|
#endif
|
|
origbuf = NULL;
|
|
origbufsize = 0;
|
|
#if !defined(NO_B_MALLOC)
|
|
/*
|
|
* If the buffer is growing on it's other-than-first allocation,
|
|
* then we revert to the page-allocation scheme.
|
|
*/
|
|
if (bp->b_flags & B_MALLOC) {
|
|
origbuf = bp->b_data;
|
|
origbufsize = bp->b_bufsize;
|
|
bp->b_data = (caddr_t) buffers_kva + (bp - buf) * MAXBSIZE;
|
|
bufspace -= bp->b_bufsize;
|
|
bufmallocspace -= bp->b_bufsize;
|
|
bp->b_bufsize = 0;
|
|
bp->b_flags &= ~B_MALLOC;
|
|
newbsize = round_page(newbsize);
|
|
}
|
|
#endif
|
|
vm_hold_load_pages(
|
|
bp,
|
|
(vm_offset_t) bp->b_data + bp->b_bufsize,
|
|
(vm_offset_t) bp->b_data + newbsize);
|
|
#if !defined(NO_B_MALLOC)
|
|
if (origbuf) {
|
|
bcopy(origbuf, bp->b_data, origbufsize);
|
|
free(origbuf, M_BIOBUF);
|
|
}
|
|
#endif
|
|
}
|
|
} else {
|
|
vm_page_t m;
|
|
int desiredpages;
|
|
|
|
newbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1);
|
|
desiredpages = (round_page(newbsize) >> PAGE_SHIFT);
|
|
|
|
#if !defined(NO_B_MALLOC)
|
|
if (bp->b_flags & B_MALLOC)
|
|
panic("allocbuf: VMIO buffer can't be malloced");
|
|
#endif
|
|
|
|
if (newbsize < bp->b_bufsize) {
|
|
if (desiredpages < bp->b_npages) {
|
|
for (i = desiredpages; i < bp->b_npages; i++) {
|
|
/*
|
|
* the page is not freed here -- it
|
|
* is the responsibility of vnode_pager_setsize
|
|
*/
|
|
m = bp->b_pages[i];
|
|
#if defined(DIAGNOSTIC)
|
|
if (m == bogus_page)
|
|
panic("allocbuf: bogus page found");
|
|
#endif
|
|
s = splvm();
|
|
while ((m->flags & PG_BUSY) || (m->busy != 0)) {
|
|
m->flags |= PG_WANTED;
|
|
tsleep(m, PVM, "biodep", 0);
|
|
}
|
|
splx(s);
|
|
|
|
bp->b_pages[i] = NULL;
|
|
vm_page_unwire(m);
|
|
}
|
|
pmap_qremove((vm_offset_t) trunc_page(bp->b_data) +
|
|
(desiredpages << PAGE_SHIFT), (bp->b_npages - desiredpages));
|
|
bp->b_npages = desiredpages;
|
|
}
|
|
} else if (newbsize > bp->b_bufsize) {
|
|
vm_object_t obj;
|
|
vm_offset_t tinc, toff;
|
|
vm_ooffset_t off;
|
|
vm_pindex_t objoff;
|
|
int pageindex, curbpnpages;
|
|
struct vnode *vp;
|
|
int bsize;
|
|
|
|
vp = bp->b_vp;
|
|
|
|
if (vp->v_type == VBLK)
|
|
bsize = DEV_BSIZE;
|
|
else
|
|
bsize = vp->v_mount->mnt_stat.f_iosize;
|
|
|
|
if (bp->b_npages < desiredpages) {
|
|
obj = vp->v_object;
|
|
tinc = PAGE_SIZE;
|
|
if (tinc > bsize)
|
|
tinc = bsize;
|
|
off = (vm_ooffset_t) bp->b_lblkno * bsize;
|
|
curbpnpages = bp->b_npages;
|
|
doretry:
|
|
bp->b_flags |= B_CACHE;
|
|
for (toff = 0; toff < newbsize; toff += tinc) {
|
|
int bytesinpage;
|
|
|
|
pageindex = toff >> PAGE_SHIFT;
|
|
objoff = OFF_TO_IDX(off + toff);
|
|
if (pageindex < curbpnpages) {
|
|
|
|
m = bp->b_pages[pageindex];
|
|
#ifdef VFS_BIO_DIAG
|
|
if (m->pindex != objoff)
|
|
panic("allocbuf: page changed offset??!!!?");
|
|
#endif
|
|
bytesinpage = tinc;
|
|
if (tinc > (newbsize - toff))
|
|
bytesinpage = newbsize - toff;
|
|
if ((bp->b_flags & B_CACHE) &&
|
|
!vm_page_is_valid(m,
|
|
(vm_offset_t) ((toff + off) & PAGE_MASK),
|
|
bytesinpage)) {
|
|
bp->b_flags &= ~B_CACHE;
|
|
}
|
|
continue;
|
|
}
|
|
m = vm_page_lookup(obj, objoff);
|
|
if (!m) {
|
|
m = vm_page_alloc(obj, objoff, VM_ALLOC_NORMAL);
|
|
if (!m) {
|
|
VM_WAIT;
|
|
goto doretry;
|
|
}
|
|
/*
|
|
* Normally it is unwise to clear PG_BUSY without
|
|
* PAGE_WAKEUP -- but it is okay here, as there is
|
|
* no chance for blocking between here and vm_page_alloc
|
|
*/
|
|
m->flags &= ~PG_BUSY;
|
|
vm_page_wire(m);
|
|
bp->b_flags &= ~B_CACHE;
|
|
} else if (m->flags & PG_BUSY) {
|
|
s = splvm();
|
|
if (m->flags & PG_BUSY) {
|
|
m->flags |= PG_WANTED;
|
|
tsleep(m, PVM, "pgtblk", 0);
|
|
}
|
|
splx(s);
|
|
goto doretry;
|
|
} else {
|
|
if ((curproc != pageproc) &&
|
|
((m->queue - m->pc) == PQ_CACHE) &&
|
|
((cnt.v_free_count + cnt.v_cache_count) <
|
|
(cnt.v_free_min + cnt.v_cache_min))) {
|
|
pagedaemon_wakeup();
|
|
}
|
|
bytesinpage = tinc;
|
|
if (tinc > (newbsize - toff))
|
|
bytesinpage = newbsize - toff;
|
|
if ((bp->b_flags & B_CACHE) &&
|
|
!vm_page_is_valid(m,
|
|
(vm_offset_t) ((toff + off) & PAGE_MASK),
|
|
bytesinpage)) {
|
|
bp->b_flags &= ~B_CACHE;
|
|
}
|
|
vm_page_wire(m);
|
|
}
|
|
bp->b_pages[pageindex] = m;
|
|
curbpnpages = pageindex + 1;
|
|
}
|
|
bp->b_data = (caddr_t) trunc_page(bp->b_data);
|
|
bp->b_npages = curbpnpages;
|
|
pmap_qenter((vm_offset_t) bp->b_data,
|
|
bp->b_pages, bp->b_npages);
|
|
((vm_offset_t) bp->b_data) |= off & PAGE_MASK;
|
|
}
|
|
}
|
|
}
|
|
if (bp->b_flags & B_VMIO)
|
|
vmiospace += bp->b_bufsize;
|
|
bufspace += (newbsize - bp->b_bufsize);
|
|
bp->b_bufsize = newbsize;
|
|
bp->b_bcount = size;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Wait for buffer I/O completion, returning error status.
|
|
*/
|
|
int
|
|
biowait(register struct buf * bp)
|
|
{
|
|
int s;
|
|
|
|
s = splbio();
|
|
while ((bp->b_flags & B_DONE) == 0)
|
|
tsleep(bp, PRIBIO, "biowait", 0);
|
|
splx(s);
|
|
if (bp->b_flags & B_EINTR) {
|
|
bp->b_flags &= ~B_EINTR;
|
|
return (EINTR);
|
|
}
|
|
if (bp->b_flags & B_ERROR) {
|
|
return (bp->b_error ? bp->b_error : EIO);
|
|
} else {
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Finish I/O on a buffer, calling an optional function.
|
|
* This is usually called from interrupt level, so process blocking
|
|
* is not *a good idea*.
|
|
*/
|
|
void
|
|
biodone(register struct buf * bp)
|
|
{
|
|
int s;
|
|
|
|
s = splbio();
|
|
if (!(bp->b_flags & B_BUSY))
|
|
panic("biodone: buffer not busy");
|
|
|
|
if (bp->b_flags & B_DONE) {
|
|
splx(s);
|
|
printf("biodone: buffer already done\n");
|
|
return;
|
|
}
|
|
bp->b_flags |= B_DONE;
|
|
|
|
if ((bp->b_flags & B_READ) == 0) {
|
|
vwakeup(bp);
|
|
}
|
|
#ifdef BOUNCE_BUFFERS
|
|
if (bp->b_flags & B_BOUNCE)
|
|
vm_bounce_free(bp);
|
|
#endif
|
|
|
|
/* call optional completion function if requested */
|
|
if (bp->b_flags & B_CALL) {
|
|
bp->b_flags &= ~B_CALL;
|
|
(*bp->b_iodone) (bp);
|
|
splx(s);
|
|
return;
|
|
}
|
|
if (bp->b_flags & B_VMIO) {
|
|
int i, resid;
|
|
vm_ooffset_t foff;
|
|
vm_page_t m;
|
|
vm_object_t obj;
|
|
int iosize;
|
|
struct vnode *vp = bp->b_vp;
|
|
|
|
if (vp->v_type == VBLK)
|
|
foff = (vm_ooffset_t) DEV_BSIZE * bp->b_lblkno;
|
|
else
|
|
foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno;
|
|
obj = vp->v_object;
|
|
if (!obj) {
|
|
panic("biodone: no object");
|
|
}
|
|
#if defined(VFS_BIO_DEBUG)
|
|
if (obj->paging_in_progress < bp->b_npages) {
|
|
printf("biodone: paging in progress(%d) < bp->b_npages(%d)\n",
|
|
obj->paging_in_progress, bp->b_npages);
|
|
}
|
|
#endif
|
|
iosize = bp->b_bufsize;
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
int bogusflag = 0;
|
|
m = bp->b_pages[i];
|
|
if (m == bogus_page) {
|
|
bogusflag = 1;
|
|
m = vm_page_lookup(obj, OFF_TO_IDX(foff));
|
|
if (!m) {
|
|
#if defined(VFS_BIO_DEBUG)
|
|
printf("biodone: page disappeared\n");
|
|
#endif
|
|
--obj->paging_in_progress;
|
|
continue;
|
|
}
|
|
bp->b_pages[i] = m;
|
|
pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages);
|
|
}
|
|
#if defined(VFS_BIO_DEBUG)
|
|
if (OFF_TO_IDX(foff) != m->pindex) {
|
|
printf("biodone: foff(%d)/m->pindex(%d) mismatch\n", foff, m->pindex);
|
|
}
|
|
#endif
|
|
resid = IDX_TO_OFF(m->pindex + 1) - foff;
|
|
if (resid > iosize)
|
|
resid = iosize;
|
|
/*
|
|
* In the write case, the valid and clean bits are
|
|
* already changed correctly, so we only need to do this
|
|
* here in the read case.
|
|
*/
|
|
if ((bp->b_flags & B_READ) && !bogusflag && resid > 0) {
|
|
vm_page_set_validclean(m,
|
|
(vm_offset_t) (foff & PAGE_MASK), resid);
|
|
}
|
|
|
|
/*
|
|
* when debugging new filesystems or buffer I/O methods, this
|
|
* is the most common error that pops up. if you see this, you
|
|
* have not set the page busy flag correctly!!!
|
|
*/
|
|
if (m->busy == 0) {
|
|
printf("biodone: page busy < 0, "
|
|
"pindex: %d, foff: 0x(%x,%x), "
|
|
"resid: %d, index: %d\n",
|
|
(int) m->pindex, (int)(foff >> 32),
|
|
(int) foff & 0xffffffff, resid, i);
|
|
if (vp->v_type != VBLK)
|
|
printf(" iosize: %ld, lblkno: %d, flags: 0x%lx, npages: %d\n",
|
|
bp->b_vp->v_mount->mnt_stat.f_iosize,
|
|
(int) bp->b_lblkno,
|
|
bp->b_flags, bp->b_npages);
|
|
else
|
|
printf(" VDEV, lblkno: %d, flags: 0x%lx, npages: %d\n",
|
|
(int) bp->b_lblkno,
|
|
bp->b_flags, bp->b_npages);
|
|
printf(" valid: 0x%x, dirty: 0x%x, wired: %d\n",
|
|
m->valid, m->dirty, m->wire_count);
|
|
panic("biodone: page busy < 0\n");
|
|
}
|
|
--m->busy;
|
|
if ((m->busy == 0) && (m->flags & PG_WANTED)) {
|
|
m->flags &= ~PG_WANTED;
|
|
wakeup(m);
|
|
}
|
|
--obj->paging_in_progress;
|
|
foff += resid;
|
|
iosize -= resid;
|
|
}
|
|
if (obj && obj->paging_in_progress == 0 &&
|
|
(obj->flags & OBJ_PIPWNT)) {
|
|
obj->flags &= ~OBJ_PIPWNT;
|
|
wakeup(obj);
|
|
}
|
|
}
|
|
/*
|
|
* For asynchronous completions, release the buffer now. The brelse
|
|
* checks for B_WANTED and will do the wakeup there if necessary - so
|
|
* no need to do a wakeup here in the async case.
|
|
*/
|
|
|
|
if (bp->b_flags & B_ASYNC) {
|
|
if ((bp->b_flags & B_ORDERED) == 0) {
|
|
if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0)
|
|
brelse(bp);
|
|
else
|
|
bqrelse(bp);
|
|
}
|
|
} else {
|
|
bp->b_flags &= ~B_WANTED;
|
|
wakeup(bp);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
int
|
|
count_lock_queue()
|
|
{
|
|
int count;
|
|
struct buf *bp;
|
|
|
|
count = 0;
|
|
for (bp = TAILQ_FIRST(&bufqueues[QUEUE_LOCKED]);
|
|
bp != NULL;
|
|
bp = TAILQ_NEXT(bp, b_freelist))
|
|
count++;
|
|
return (count);
|
|
}
|
|
|
|
int vfs_update_interval = 30;
|
|
|
|
static void
|
|
vfs_update()
|
|
{
|
|
(void) spl0(); /* XXX redundant? wrong place? */
|
|
while (1) {
|
|
tsleep(&vfs_update_wakeup, PUSER, "update",
|
|
hz * vfs_update_interval);
|
|
vfs_update_wakeup = 0;
|
|
sync(curproc, NULL, NULL);
|
|
}
|
|
}
|
|
|
|
static int
|
|
sysctl_kern_updateinterval SYSCTL_HANDLER_ARGS
|
|
{
|
|
int error = sysctl_handle_int(oidp,
|
|
oidp->oid_arg1, oidp->oid_arg2, req);
|
|
if (!error)
|
|
wakeup(&vfs_update_wakeup);
|
|
return error;
|
|
}
|
|
|
|
SYSCTL_PROC(_kern, KERN_UPDATEINTERVAL, update, CTLTYPE_INT|CTLFLAG_RW,
|
|
&vfs_update_interval, 0, sysctl_kern_updateinterval, "I", "");
|
|
|
|
|
|
/*
|
|
* This routine is called in lieu of iodone in the case of
|
|
* incomplete I/O. This keeps the busy status for pages
|
|
* consistant.
|
|
*/
|
|
void
|
|
vfs_unbusy_pages(struct buf * bp)
|
|
{
|
|
int i;
|
|
|
|
if (bp->b_flags & B_VMIO) {
|
|
struct vnode *vp = bp->b_vp;
|
|
vm_object_t obj = vp->v_object;
|
|
vm_ooffset_t foff;
|
|
|
|
foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno;
|
|
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
vm_page_t m = bp->b_pages[i];
|
|
|
|
if (m == bogus_page) {
|
|
m = vm_page_lookup(obj, OFF_TO_IDX(foff) + i);
|
|
if (!m) {
|
|
panic("vfs_unbusy_pages: page missing\n");
|
|
}
|
|
bp->b_pages[i] = m;
|
|
pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages);
|
|
}
|
|
--obj->paging_in_progress;
|
|
--m->busy;
|
|
if ((m->busy == 0) && (m->flags & PG_WANTED)) {
|
|
m->flags &= ~PG_WANTED;
|
|
wakeup(m);
|
|
}
|
|
}
|
|
if (obj->paging_in_progress == 0 &&
|
|
(obj->flags & OBJ_PIPWNT)) {
|
|
obj->flags &= ~OBJ_PIPWNT;
|
|
wakeup(obj);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 PG_BUSY. Also the object paging_in_progress
|
|
* flag is handled to make sure that the object doesn't become
|
|
* inconsistant.
|
|
*/
|
|
void
|
|
vfs_busy_pages(struct buf * bp, int clear_modify)
|
|
{
|
|
int i;
|
|
|
|
if (bp->b_flags & B_VMIO) {
|
|
vm_object_t obj = bp->b_vp->v_object;
|
|
vm_ooffset_t foff;
|
|
int iocount = bp->b_bufsize;
|
|
|
|
if (bp->b_vp->v_type == VBLK)
|
|
foff = (vm_ooffset_t) DEV_BSIZE * bp->b_lblkno;
|
|
else
|
|
foff = (vm_ooffset_t) bp->b_vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno;
|
|
vfs_setdirty(bp);
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
vm_page_t m = bp->b_pages[i];
|
|
int resid = IDX_TO_OFF(m->pindex + 1) - foff;
|
|
|
|
if (resid > iocount)
|
|
resid = iocount;
|
|
if ((bp->b_flags & B_CLUSTER) == 0) {
|
|
obj->paging_in_progress++;
|
|
m->busy++;
|
|
}
|
|
vm_page_protect(m, VM_PROT_NONE);
|
|
if (clear_modify) {
|
|
vm_page_set_validclean(m,
|
|
(vm_offset_t) (foff & PAGE_MASK), resid);
|
|
} else if (bp->b_bcount >= PAGE_SIZE) {
|
|
if (m->valid && (bp->b_flags & B_CACHE) == 0) {
|
|
bp->b_pages[i] = bogus_page;
|
|
pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages);
|
|
}
|
|
}
|
|
foff += resid;
|
|
iocount -= resid;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
void
|
|
vfs_clean_pages(struct buf * bp)
|
|
{
|
|
int i;
|
|
|
|
if (bp->b_flags & B_VMIO) {
|
|
vm_ooffset_t foff;
|
|
int iocount = bp->b_bufsize;
|
|
|
|
if (bp->b_vp->v_type == VBLK)
|
|
foff = (vm_ooffset_t) DEV_BSIZE * bp->b_lblkno;
|
|
else
|
|
foff = (vm_ooffset_t) bp->b_vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno;
|
|
|
|
for (i = 0; i < bp->b_npages; i++) {
|
|
vm_page_t m = bp->b_pages[i];
|
|
int resid = IDX_TO_OFF(m->pindex + 1) - foff;
|
|
|
|
if (resid > iocount)
|
|
resid = iocount;
|
|
if (resid > 0) {
|
|
vm_page_set_validclean(m,
|
|
((vm_offset_t) foff & PAGE_MASK), resid);
|
|
}
|
|
foff += resid;
|
|
iocount -= resid;
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
vfs_bio_clrbuf(struct buf *bp) {
|
|
int i;
|
|
if( bp->b_flags & B_VMIO) {
|
|
if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE)) {
|
|
int mask;
|
|
mask = 0;
|
|
for(i=0;i<bp->b_bufsize;i+=DEV_BSIZE)
|
|
mask |= (1 << (i/DEV_BSIZE));
|
|
if( bp->b_pages[0]->valid != mask) {
|
|
bzero(bp->b_data, bp->b_bufsize);
|
|
}
|
|
bp->b_pages[0]->valid = mask;
|
|
bp->b_resid = 0;
|
|
return;
|
|
}
|
|
for(i=0;i<bp->b_npages;i++) {
|
|
if( bp->b_pages[i]->valid == VM_PAGE_BITS_ALL)
|
|
continue;
|
|
if( bp->b_pages[i]->valid == 0) {
|
|
if ((bp->b_pages[i]->flags & PG_ZERO) == 0) {
|
|
bzero(bp->b_data + (i << PAGE_SHIFT), PAGE_SIZE);
|
|
}
|
|
} else {
|
|
int j;
|
|
for(j=0;j<PAGE_SIZE/DEV_BSIZE;j++) {
|
|
if( (bp->b_pages[i]->valid & (1<<j)) == 0)
|
|
bzero(bp->b_data + (i << PAGE_SHIFT) + j * DEV_BSIZE, DEV_BSIZE);
|
|
}
|
|
}
|
|
/* bp->b_pages[i]->valid = VM_PAGE_BITS_ALL; */
|
|
}
|
|
bp->b_resid = 0;
|
|
} else {
|
|
clrbuf(bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_hold_load_pages and vm_hold_unload pages get pages into
|
|
* a buffers address space. The pages are anonymous and are
|
|
* not associated with a file object.
|
|
*/
|
|
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;
|
|
|
|
to = round_page(to);
|
|
from = round_page(from);
|
|
index = (from - trunc_page(bp->b_data)) >> PAGE_SHIFT;
|
|
|
|
for (pg = from; pg < to; pg += PAGE_SIZE, index++) {
|
|
|
|
tryagain:
|
|
|
|
p = vm_page_alloc(kernel_object, ((pg - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT),
|
|
VM_ALLOC_NORMAL);
|
|
if (!p) {
|
|
VM_WAIT;
|
|
goto tryagain;
|
|
}
|
|
vm_page_wire(p);
|
|
pmap_kenter(pg, VM_PAGE_TO_PHYS(p));
|
|
bp->b_pages[index] = p;
|
|
PAGE_WAKEUP(p);
|
|
}
|
|
bp->b_npages = to >> PAGE_SHIFT;
|
|
}
|
|
|
|
void
|
|
vm_hold_free_pages(struct buf * bp, vm_offset_t from, vm_offset_t to)
|
|
{
|
|
vm_offset_t pg;
|
|
vm_page_t p;
|
|
int index;
|
|
|
|
from = round_page(from);
|
|
to = round_page(to);
|
|
index = (from - trunc_page(bp->b_data)) >> PAGE_SHIFT;
|
|
|
|
for (pg = from; pg < to; pg += PAGE_SIZE, index++) {
|
|
p = bp->b_pages[index];
|
|
if (p && (index < bp->b_npages)) {
|
|
if (p->busy) {
|
|
printf("vm_hold_free_pages: blkno: %d, lblkno: %d\n",
|
|
bp->b_blkno, bp->b_lblkno);
|
|
}
|
|
bp->b_pages[index] = NULL;
|
|
pmap_kremove(pg);
|
|
vm_page_unwire(p);
|
|
vm_page_free(p);
|
|
}
|
|
}
|
|
bp->b_npages = from >> PAGE_SHIFT;
|
|
}
|