diff options
Diffstat (limited to 'sys/kern/vfs_bio.c')
| -rw-r--r-- | sys/kern/vfs_bio.c | 1946 |
1 files changed, 1946 insertions, 0 deletions
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c new file mode 100644 index 0000000..6245133 --- /dev/null +++ b/sys/kern/vfs_bio.c @@ -0,0 +1,1946 @@ +/* + * Copyright (c) 1994 John S. Dyson + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice immediately at the beginning of the file, without modification, + * this list of conditions, and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Absolutely no warranty of function or purpose is made by the author + * John S. Dyson. + * 4. This work was done expressly for inclusion into FreeBSD. Other use + * is allowed if this notation is included. + * 5. Modifications may be freely made to this file if the above conditions + * are met. + * + * $FreeBSD$ + */ + +/* + * this file contains a new buffer I/O scheme implementing a coherent + * VM object and buffer cache scheme. Pains have been taken to make + * sure that the performance degradation associated with schemes such + * as this is not realized. + * + * Author: John S. Dyson + * Significant help during the development and debugging phases + * had been provided by David Greenman, also of the FreeBSD core team. + */ + +#include "opt_bounce.h" + +#define VMIO +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/sysproto.h> +#include <sys/kernel.h> +#include <sys/sysctl.h> +#include <sys/proc.h> +#include <sys/vnode.h> +#include <sys/vmmeter.h> +#include <vm/vm.h> +#include <vm/vm_param.h> +#include <vm/vm_prot.h> +#include <vm/vm_kern.h> +#include <vm/vm_pageout.h> +#include <vm/vm_page.h> +#include <vm/vm_object.h> +#include <vm/vm_extern.h> +#include <vm/lock.h> +#include <vm/vm_map.h> +#include <sys/buf.h> +#include <sys/mount.h> +#include <sys/malloc.h> +#include <sys/resourcevar.h> +#include <sys/proc.h> + +#include <miscfs/specfs/specdev.h> + +static void vfs_update __P((void)); +static struct proc *updateproc; +static struct kproc_desc up_kp = { + "update", + vfs_update, + &updateproc +}; +SYSINIT_KT(update, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp) + +struct buf *buf; /* buffer header pool */ +struct swqueue bswlist; + +int count_lock_queue __P((void)); +static void vm_hold_free_pages(struct buf * bp, vm_offset_t from, + vm_offset_t to); +static void vm_hold_load_pages(struct buf * bp, vm_offset_t from, + vm_offset_t to); +static void vfs_clean_pages(struct buf * bp); +static void vfs_setdirty(struct buf *bp); +static void vfs_vmio_release(struct buf *bp); + +int needsbuffer; + +/* + * Internal update daemon, process 3 + * The variable vfs_update_wakeup allows for internal syncs. + */ +int vfs_update_wakeup; + + +/* + * buffers base kva + */ + +/* + * bogus page -- for I/O to/from partially complete buffers + * this is a temporary solution to the problem, but it is not + * really that bad. it would be better to split the buffer + * for input in the case of buffers partially already in memory, + * but the code is intricate enough already. + */ +vm_page_t bogus_page; +static vm_offset_t bogus_offset; + +static int bufspace, maxbufspace, vmiospace, maxvmiobufspace, + bufmallocspace, maxbufmallocspace; + +static struct bufhashhdr bufhashtbl[BUFHSZ], invalhash; +static struct bqueues bufqueues[BUFFER_QUEUES]; + +extern int vm_swap_size; + +#define BUF_MAXUSE 16 + +/* + * Initialize buffer headers and related structures. + */ +void +bufinit() +{ + struct buf *bp; + int i; + + TAILQ_INIT(&bswlist); + LIST_INIT(&invalhash); + + /* first, make a null hash table */ + for (i = 0; i < BUFHSZ; i++) + LIST_INIT(&bufhashtbl[i]); + + /* next, make a null set of free lists */ + for (i = 0; i < BUFFER_QUEUES; i++) + TAILQ_INIT(&bufqueues[i]); + + /* 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; /* we're just an empty header */ + bp->b_dev = NODEV; + bp->b_rcred = NOCRED; + bp->b_wcred = NOCRED; + bp->b_qindex = QUEUE_EMPTY; + bp->b_vnbufs.le_next = NOLIST; + TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); + LIST_INSERT_HEAD(&invalhash, bp, b_hash); + } +/* + * maxbufspace is currently calculated to support all filesystem blocks + * to be 8K. If you happen to use a 16K filesystem, the size of the buffer + * cache is still the same as it would be for 8K filesystems. This + * keeps the size of the buffer cache "in check" for big block filesystems. + */ + maxbufspace = (nbuf + 8) * DFLTBSIZE; +/* + * reserve 1/3 of the buffers for metadata (VDIR) which might not be VMIO'ed + */ + maxvmiobufspace = 2 * maxbufspace / 3; +/* + * 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 = maxbufspace / 20; + + bogus_offset = kmem_alloc_pageable(kernel_map, PAGE_SIZE); + bogus_page = vm_page_alloc(kernel_object, + ((bogus_offset - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), + VM_ALLOC_NORMAL); + +} + +/* + * Free the kva allocation for a buffer + * Must be called only at splbio or higher, + * as this is the only locking for buffer_map. + */ +static void +bfreekva(struct buf * bp) +{ + if (bp->b_kvasize == 0) + return; + + vm_map_delete(buffer_map, + (vm_offset_t) bp->b_kvabase, + (vm_offset_t) bp->b_kvabase + bp->b_kvasize); + + bp->b_kvasize = 0; + +} + +/* + * remove the buffer from the appropriate free list + */ +void +bremfree(struct buf * bp) +{ + int s = splbio(); + + if (bp->b_qindex != QUEUE_NONE) { + TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist); + bp->b_qindex = QUEUE_NONE; + } else { + panic("bremfree: removing a buffer when not on a queue"); + } + splx(s); +} + +/* + * Get a buffer with the specified data. Look in the cache first. + */ +int +bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred, + struct buf ** bpp) +{ + struct buf *bp; + + bp = getblk(vp, blkno, size, 0, 0); + *bpp = bp; + + /* if not found in cache, do some I/O */ + if ((bp->b_flags & B_CACHE) == 0) { + if (curproc != NULL) + curproc->p_stats->p_ru.ru_inblock++; + bp->b_flags |= B_READ; + bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); + if (bp->b_rcred == NOCRED) { + if (cred != NOCRED) + crhold(cred); + bp->b_rcred = cred; + } + vfs_busy_pages(bp, 0); + VOP_STRATEGY(bp); + return (biowait(bp)); + } + return (0); +} + +/* + * Operates like bread, but also starts asynchronous I/O on + * read-ahead blocks. + */ +int +breadn(struct vnode * vp, daddr_t blkno, int size, + daddr_t * rablkno, int *rabsize, + int cnt, struct ucred * cred, struct buf ** bpp) +{ + struct buf *bp, *rabp; + int i; + int rv = 0, readwait = 0; + + *bpp = bp = getblk(vp, blkno, size, 0, 0); + + /* if not found in cache, do some I/O */ + if ((bp->b_flags & B_CACHE) == 0) { + if (curproc != NULL) + curproc->p_stats->p_ru.ru_inblock++; + bp->b_flags |= B_READ; + bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); + if (bp->b_rcred == NOCRED) { + if (cred != NOCRED) + crhold(cred); + bp->b_rcred = cred; + } + vfs_busy_pages(bp, 0); + VOP_STRATEGY(bp); + ++readwait; + } + for (i = 0; i < cnt; i++, rablkno++, rabsize++) { + if (inmem(vp, *rablkno)) + continue; + rabp = getblk(vp, *rablkno, *rabsize, 0, 0); + + if ((rabp->b_flags & B_CACHE) == 0) { + if (curproc != NULL) + curproc->p_stats->p_ru.ru_inblock++; + rabp->b_flags |= B_READ | B_ASYNC; + rabp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); + if (rabp->b_rcred == NOCRED) { + if (cred != NOCRED) + crhold(cred); + rabp->b_rcred = cred; + } + vfs_busy_pages(rabp, 0); + VOP_STRATEGY(rabp); + } else { + brelse(rabp); + } + } + + if (readwait) { + rv = biowait(bp); + } + return (rv); +} + +/* + * Write, release buffer on completion. (Done by iodone + * if async.) + */ +int +bwrite(struct buf * bp) +{ + int oldflags = bp->b_flags; + + if (bp->b_flags & B_INVAL) { + brelse(bp); + return (0); + } + if (!(bp->b_flags & B_BUSY)) + panic("bwrite: buffer is not busy???"); + + bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI); + bp->b_flags |= B_WRITEINPROG; + + if ((oldflags & (B_ASYNC|B_DELWRI)) == (B_ASYNC|B_DELWRI)) { + reassignbuf(bp, bp->b_vp); + } + + bp->b_vp->v_numoutput++; + vfs_busy_pages(bp, 1); + if (curproc != NULL) + curproc->p_stats->p_ru.ru_oublock++; + VOP_STRATEGY(bp); + + /* + * Handle ordered writes here. + * If the write was originally flagged as ordered, + * then we check to see if it was converted to async. + * If it was converted to async, and is done now, then + * we release the buffer. Otherwise we clear the + * ordered flag because it is not needed anymore. + * + * Note that biodone has been modified so that it does + * not release ordered buffers. This allows us to have + * a chance to determine whether or not the driver + * has set the async flag in the strategy routine. Otherwise + * if biodone was not modified, then the buffer may have been + * reused before we have had a chance to check the flag. + */ + + if ((oldflags & B_ORDERED) == B_ORDERED) { + int s; + s = splbio(); + if (bp->b_flags & B_ASYNC) { + if ((bp->b_flags & B_DONE)) { + if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0) + brelse(bp); + else + bqrelse(bp); + } + splx(s); + return (0); + } else { + bp->b_flags &= ~B_ORDERED; + } + splx(s); + } + + if ((oldflags & B_ASYNC) == 0) { + int rtval = biowait(bp); + + if (oldflags & B_DELWRI) { + reassignbuf(bp, bp->b_vp); + } + brelse(bp); + return (rtval); + } + return (0); +} + +int +vn_bwrite(ap) + struct vop_bwrite_args *ap; +{ + return (bwrite(ap->a_bp)); +} + +/* + * Delayed write. (Buffer is marked dirty). + */ +void +bdwrite(struct buf * bp) +{ + + if ((bp->b_flags & B_BUSY) == 0) { + panic("bdwrite: buffer is not busy"); + } + if (bp->b_flags & B_INVAL) { + brelse(bp); + return; + } + if (bp->b_flags & B_TAPE) { + bawrite(bp); + return; + } + bp->b_flags &= ~(B_READ|B_RELBUF); + if ((bp->b_flags & B_DELWRI) == 0) { + bp->b_flags |= B_DONE | B_DELWRI; + reassignbuf(bp, bp->b_vp); + } + + /* + * 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( bp->b_lblkno == bp->b_blkno) { + VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); + } + + /* + * Set the *dirty* buffer range based upon the VM system dirty pages. + */ + vfs_setdirty(bp); + + /* + * 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(bp); + bqrelse(bp); + 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 +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; + /* + * Get rid of the kva allocation *now* + */ + bfreekva(bp); + 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. + */ +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 size, int maxsize) +{ + struct buf *bp; + int nbyteswritten = 0; + vm_offset_t addr; + +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_dirtyoff = bp->b_dirtyend = 0; + bp->b_validoff = bp->b_validend = 0; + bp->b_usecount = 4; + + maxsize = (maxsize + PAGE_MASK) & ~PAGE_MASK; + + /* + * we assume that buffer_map is not at address 0 + */ + addr = 0; + if (maxsize != bp->b_kvasize) { + bfreekva(bp); + + /* + * See if we have buffer kva space + */ + if (vm_map_findspace(buffer_map, + vm_map_min(buffer_map), maxsize, &addr)) { + bp->b_flags |= B_INVAL; + brelse(bp); + goto trytofreespace; + } + } + + /* + * See if we are below are allocated minimum + */ + if (bufspace >= (maxbufspace + nbyteswritten)) { + bp->b_flags |= B_INVAL; + brelse(bp); + goto trytofreespace; + } + + /* + * create a map entry for the buffer -- in essence + * reserving the kva space. + */ + if (addr) { + vm_map_insert(buffer_map, NULL, 0, + addr, addr + maxsize, + VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); + + bp->b_kvabase = (caddr_t) addr; + bp->b_kvasize = maxsize; + } + bp->b_data = bp->b_kvabase; + + 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; + int maxsize; + + if (vp->v_mount) { + maxsize = vp->v_mount->mnt_stat.f_iosize; + /* + * This happens on mount points. + */ + if (maxsize < size) + maxsize = size; + } else { + maxsize = size; + } + + if (size > MAXBSIZE) + panic("getblk: size(%d) > MAXBSIZE(%d)\n", size, MAXBSIZE); + + 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) && (size <= bp->b_kvasize)) { + 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; + + if ((bp = getnewbuf(slpflag, slptimeo, size, maxsize)) == 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 ((obj = vp->v_object) && (vp->v_flag & VVMIO)) { + 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, size, MAXBSIZE)) == 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_kvasize < size) + panic("allocbuf: buffer too small"); + + 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 = bp->b_kvabase; + 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 = bp->b_kvabase; + 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() +{ + 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; +} |
