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Add diagnostic check on cluster_rbuild to make sure I/O.
[unix-history] / usr / src / sys / kern / vfs_bio.c
/*-
* Copyright (c) 1982, 1986, 1989 The Regents of the University of California.
* All rights reserved.
*
* This module is believed to contain source code proprietary to AT&T.
* Use and redistribution is subject to the Berkeley Software License
* Agreement and your Software Agreement with AT&T (Western Electric).
*
* @(#)vfs_bio.c 7.59 (Berkeley) %G%
*/
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/trace.h>
#include <sys/resourcevar.h>
#include <sys/malloc.h>
#include <libkern/libkern.h>
/*
* Definitions for the buffer hash lists.
*/
#define BUFHASH(dvp, lbn) \
(&bufhashtbl[((int)(dvp) / sizeof(*(dvp)) + (int)(lbn)) & bufhash])
struct list_entry *bufhashtbl, invalhash;
u_long bufhash;
/*
* Insq/Remq for the buffer hash lists.
*/
#define binshash(bp, dp) list_enter_head(dp, bp, struct buf *, b_hash)
#define bremhash(bp) list_remove(bp, struct buf *, b_hash)
/*
* Definitions for the buffer free lists.
*/
#define BQUEUES 4 /* number of free buffer queues */
#define BQ_LOCKED 0 /* super-blocks &c */
#define BQ_LRU 1 /* lru, useful buffers */
#define BQ_AGE 2 /* rubbish */
#define BQ_EMPTY 3 /* buffer headers with no memory */
struct queue_entry bufqueues[BQUEUES];
int needbuffer;
/*
* Insq/Remq for the buffer free lists.
*/
#define binsheadfree(bp, dp) \
queue_enter_head(dp, bp, struct buf *, b_freelist)
#define binstailfree(bp, dp) \
queue_enter_tail(dp, bp, struct buf *, b_freelist)
/*
* Local declarations
*/
struct buf *cluster_newbuf __P((struct vnode *, struct buf *, long, daddr_t,
daddr_t, long, int));
struct buf *cluster_rbuild __P((struct vnode *, u_quad_t, struct buf *,
daddr_t, daddr_t, long, int, long));
void cluster_wbuild __P((struct vnode *, struct buf *, long size,
daddr_t start_lbn, int len, daddr_t lbn));
void
bremfree(bp)
struct buf *bp;
{
struct queue_entry *dp;
/*
* We only calculate the head of the freelist when removing
* the last element of the list as that is the only time that
* it is needed (e.g. to reset the tail pointer).
*/
if (bp->b_freelist.qe_next == NULL) {
for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++)
if (dp->qe_prev == &bp->b_freelist.qe_next)
break;
if (dp == &bufqueues[BQUEUES])
panic("bremfree: lost tail");
}
queue_remove(dp, bp, struct buf *, b_freelist);
}
/*
* Initialize buffers and hash links for buffers.
*/
void
bufinit()
{
register struct buf *bp;
struct queue_entry *dp;
register int i;
int base, residual;
for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++)
queue_init(dp);
bufhashtbl = (struct list_entry *)hashinit(nbuf, M_CACHE, &bufhash);
base = bufpages / nbuf;
residual = bufpages % nbuf;
for (i = 0; i < nbuf; i++) {
bp = &buf[i];
bzero((char *)bp, sizeof *bp);
bp->b_dev = NODEV;
bp->b_rcred = NOCRED;
bp->b_wcred = NOCRED;
bp->b_un.b_addr = buffers + i * MAXBSIZE;
if (i < residual)
bp->b_bufsize = (base + 1) * CLBYTES;
else
bp->b_bufsize = base * CLBYTES;
bp->b_flags = B_INVAL;
dp = bp->b_bufsize ? &bufqueues[BQ_AGE] : &bufqueues[BQ_EMPTY];
binsheadfree(bp, dp);
binshash(bp, &invalhash);
}
}
/*
* Find the block in the buffer pool.
* If the buffer is not present, allocate a new buffer and load
* its contents according to the filesystem fill routine.
*/
bread(vp, blkno, size, cred, bpp)
struct vnode *vp;
daddr_t blkno;
int size;
struct ucred *cred;
struct buf **bpp;
#ifdef SECSIZE
long secsize;
#endif SECSIZE
{
struct proc *p = curproc; /* XXX */
register struct buf *bp;
if (size == 0)
panic("bread: size 0");
#ifdef SECSIZE
bp = getblk(dev, blkno, size, secsize);
#else SECSIZE
*bpp = bp = getblk(vp, blkno, size, 0, 0);
#endif SECSIZE
if (bp->b_flags & (B_DONE | B_DELWRI)) {
trace(TR_BREADHIT, pack(vp, size), blkno);
return (0);
}
bp->b_flags |= B_READ;
if (bp->b_bcount > bp->b_bufsize)
panic("bread");
if (bp->b_rcred == NOCRED && cred != NOCRED) {
crhold(cred);
bp->b_rcred = cred;
}
VOP_STRATEGY(bp);
trace(TR_BREADMISS, pack(vp, size), blkno);
p->p_stats->p_ru.ru_inblock++; /* pay for read */
return (biowait(bp));
}
/*
* Operates like bread, but also starts I/O on the N specified
* read-ahead blocks.
*/
breadn(vp, blkno, size, rablkno, rabsize, num, cred, bpp)
struct vnode *vp;
daddr_t blkno; int size;
#ifdef SECSIZE
long secsize;
#endif SECSIZE
daddr_t rablkno[]; int rabsize[];
int num;
struct ucred *cred;
struct buf **bpp;
{
struct proc *p = curproc; /* XXX */
register struct buf *bp, *rabp;
register int i;
bp = NULL;
/*
* If the block is not memory resident,
* allocate a buffer and start I/O.
*/
if (!incore(vp, blkno)) {
*bpp = bp = getblk(vp, blkno, size, 0, 0);
#endif SECSIZE
if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) {
bp->b_flags |= B_READ;
if (bp->b_bcount > bp->b_bufsize)
panic("breadn");
if (bp->b_rcred == NOCRED && cred != NOCRED) {
crhold(cred);
bp->b_rcred = cred;
}
VOP_STRATEGY(bp);
trace(TR_BREADMISS, pack(vp, size), blkno);
p->p_stats->p_ru.ru_inblock++; /* pay for read */
} else {
trace(TR_BREADHIT, pack(vp, size), blkno);
}
}
/*
* If there's read-ahead block(s), start I/O
* on them also (as above).
*/
for (i = 0; i < num; i++) {
if (incore(vp, rablkno[i]))
continue;
rabp = getblk(vp, rablkno[i], rabsize[i], 0, 0);
#endif SECSIZE
if (rabp->b_flags & (B_DONE | B_DELWRI)) {
brelse(rabp);
trace(TR_BREADHITRA, pack(vp, rabsize[i]), rablkno[i]);
} else {
rabp->b_flags |= B_ASYNC | B_READ;
if (rabp->b_bcount > rabp->b_bufsize)
panic("breadrabp");
if (rabp->b_rcred == NOCRED && cred != NOCRED) {
crhold(cred);
rabp->b_rcred = cred;
}
VOP_STRATEGY(rabp);
trace(TR_BREADMISSRA, pack(vp, rabsize[i]), rablkno[i]);
p->p_stats->p_ru.ru_inblock++; /* pay in advance */
}
}
/*
* If block was memory resident, let bread get it.
* If block was not memory resident, the read was
* started above, so just wait for the read to complete.
*/
if (bp == NULL)
#ifdef SECSIZE
return (bread(dev, blkno, size, secsize));
#else SECSIZE
return (bread(vp, blkno, size, cred, bpp));
return (biowait(bp));
}
/*
* We could optimize this by keeping track of where the last read-ahead
* was, but it would involve adding fields to the vnode. For now, let's
* just get it working.
*
* This replaces bread. If this is a bread at the beginning of a file and
* lastr is 0, we assume this is the first read and we'll read up to two
* blocks if they are sequential. After that, we'll do regular read ahead
* in clustered chunks.
*
* There are 4 or 5 cases depending on how you count:
* Desired block is in the cache:
* 1 Not sequential access (0 I/Os).
* 2 Access is sequential, do read-ahead (1 ASYNC).
* Desired block is not in cache:
* 3 Not sequential access (1 SYNC).
* 4 Sequential access, next block is contiguous (1 SYNC).
* 5 Sequential access, next block is not contiguous (1 SYNC, 1 ASYNC)
*
* There are potentially two buffers that require I/O.
* bp is the block requested.
* rbp is the read-ahead block.
* If either is NULL, then you don't have to do the I/O.
*/
cluster_read(vp, filesize, lblkno, size, cred, bpp)
struct vnode *vp;
u_quad_t filesize;
daddr_t lblkno;
long size;
struct ucred *cred;
struct buf **bpp;
{
struct buf *bp, *rbp;
daddr_t blkno, ioblkno;
long flags;
int error, num_ra, alreadyincore;
#ifdef DIAGNOSTIC
if (size == 0)
panic("cluster_read: size = 0");
#endif
error = 0;
flags = B_READ;
*bpp = bp = getblk(vp, lblkno, size, 0, 0);
if (bp->b_flags & (B_CACHE | B_DONE | B_DELWRI)) {
/*
* Desired block is in cache; do any readahead ASYNC.
* Case 1, 2.
*/
trace(TR_BREADHIT, pack(vp, size), lblkno);
flags |= B_ASYNC;
ioblkno = lblkno +
(lblkno < vp->v_ralen ? vp->v_ralen >> 1 : vp->v_ralen);
alreadyincore = (int)incore(vp, ioblkno);
bp = NULL;
} else {
/* Block wasn't in cache, case 3, 4, 5. */
trace(TR_BREADMISS, pack(vp, size), lblkno);
ioblkno = lblkno;
bp->b_flags |= flags;
alreadyincore = 0;
curproc->p_stats->p_ru.ru_inblock++; /* XXX */
}
/*
* XXX
* Replace 1 with a window size based on some permutation of
* maxcontig and rot_delay. This will let you figure out how
* many blocks you should read-ahead (case 2, 4, 5).
*
* If the access isn't sequential, cut the window size in half.
*/
rbp = NULL;
if (lblkno != vp->v_lastr + 1 && lblkno != 0)
vp->v_ralen = max(vp->v_ralen >> 1, 1);
else if ((ioblkno + 1) * size < filesize && !alreadyincore &&
!(error = VOP_BMAP(vp, ioblkno, NULL, &blkno, &num_ra))) {
/*
* Reading sequentially, and the next block is not in the
* cache. We are going to try reading ahead. If this is
* the first read of a file, then limit read-ahead to a
* single block, else read as much as we're allowed.
*/
if (num_ra > vp->v_ralen) {
num_ra = vp->v_ralen;
vp->v_ralen = min(MAXPHYS / size, vp->v_ralen << 1);
} else
vp->v_ralen = num_ra + 1;
if (num_ra) /* case 2, 4 */
rbp = cluster_rbuild(vp, filesize,
bp, ioblkno, blkno, size, num_ra, flags);
else if (lblkno != 0 && ioblkno == lblkno) {
/* Case 5: check how many blocks to read ahead */
++ioblkno;
if ((ioblkno + 1) * size > filesize ||
(error = VOP_BMAP(vp,
ioblkno, NULL, &blkno, &num_ra)))
goto skip_readahead;
flags |= B_ASYNC;
if (num_ra)
rbp = cluster_rbuild(vp, filesize,
NULL, ioblkno, blkno, size, num_ra, flags);
else {
rbp = getblk(vp, ioblkno, size, 0, 0);
rbp->b_flags |= flags;
rbp->b_blkno = blkno;
}
} else if (lblkno != 0) {
/* case 2; read ahead single block */
rbp = getblk(vp, ioblkno, size, 0, 0);
rbp->b_flags |= flags;
rbp->b_blkno = blkno;
} else if (bp) /* case 1, 3, block 0 */
bp->b_blkno = blkno;
/* Case 1 on block 0; not really doing sequential I/O */
if (rbp == bp) /* case 4 */
rbp = NULL;
else if (rbp) { /* case 2, 5 */
trace(TR_BREADMISSRA,
pack(vp, (num_ra + 1) * size), ioblkno);
curproc->p_stats->p_ru.ru_inblock++; /* XXX */
}
}
/* XXX Kirk, do we need to make sure the bp has creds? */
skip_readahead:
if (bp)
if (bp->b_flags & (B_DONE | B_DELWRI))
panic("cluster_read: DONE bp");
else
error = VOP_STRATEGY(bp);
if (rbp)
if (error || rbp->b_flags & (B_DONE | B_DELWRI)) {
rbp->b_flags &= ~(B_ASYNC | B_READ);
brelse(rbp);
} else
(void) VOP_STRATEGY(rbp);
if (bp)
return(biowait(bp));
return(error);
}
/*
* If blocks are contiguous on disk, use this to provide clustered
* read ahead. We will read as many blocks as possible sequentially
* and then parcel them up into logical blocks in the buffer hash table.
*/
struct buf *
cluster_rbuild(vp, filesize, bp, lbn, blkno, size, run, flags)
struct vnode *vp;
u_quad_t filesize;
struct buf *bp;
daddr_t lbn;
daddr_t blkno;
long size;
int run;
long flags;
{
struct cluster_save *b_save;
struct buf *tbp;
daddr_t bn;
int i, inc;
#ifdef DIAGNOSTIC
if (size != vp->v_mount->mnt_stat.f_iosize)
panic("cluster_rbuild: size %d != filesize %d\n",
size, vp->v_mount->mnt_stat.f_iosize);
#endif
if (size * (lbn + run + 1) > filesize)
--run;
if (run == 0) {
if (!bp) {
bp = getblk(vp, lbn, size, 0, 0);
bp->b_blkno = blkno;
bp->b_flags |= flags;
}
return(bp);
}
bp = cluster_newbuf(vp, bp, flags, blkno, lbn, size, run + 1);
if (bp->b_flags & (B_DONE | B_DELWRI))
return (bp);
b_save = malloc(sizeof(struct buf *) * run + sizeof(struct cluster_save),
M_SEGMENT, M_WAITOK);
b_save->bs_bufsize = b_save->bs_bcount = size;
b_save->bs_nchildren = 0;
b_save->bs_children = (struct buf **)(b_save + 1);
b_save->bs_saveaddr = bp->b_saveaddr;
bp->b_saveaddr = (caddr_t) b_save;
inc = size / DEV_BSIZE;
for (bn = blkno + inc, i = 1; i <= run; ++i, bn += inc) {
if (incore(vp, lbn + i)) {
if (i == 1) {
bp->b_saveaddr = b_save->bs_saveaddr;
bp->b_flags &= ~B_CALL;
bp->b_iodone = NULL;
allocbuf(bp, size);
free(b_save, M_SEGMENT);
} else
allocbuf(bp, size * i);
break;
}
tbp = getblk(vp, lbn + i, 0, 0, 0);
tbp->b_bcount = tbp->b_bufsize = size;
tbp->b_blkno = bn;
tbp->b_flags |= flags | B_READ | B_ASYNC;
++b_save->bs_nchildren;
b_save->bs_children[i - 1] = tbp;
}
if (!(bp->b_flags & B_ASYNC))
vp->v_ralen = max(vp->v_ralen - 1, 1);
return(bp);
}
/*
* Either get a new buffer or grow the existing one.
*/
struct buf *
cluster_newbuf(vp, bp, flags, blkno, lblkno, size, run)
struct vnode *vp;
struct buf *bp;
long flags;
daddr_t blkno;
daddr_t lblkno;
long size;
int run;
{
if (!bp) {
bp = getblk(vp, lblkno, size, 0, 0);
if (bp->b_flags & (B_DONE | B_DELWRI)) {
bp->b_blkno = blkno;
return(bp);
}
}
allocbuf(bp, run * size);
bp->b_blkno = blkno;
bp->b_iodone = cluster_callback;
bp->b_flags |= flags | B_CALL;
return(bp);
}
/*
* Cleanup after a clustered read or write.
*/
void
cluster_callback(bp)
struct buf *bp;
{
struct cluster_save *b_save;
struct buf **tbp;
long bsize;
caddr_t cp;
b_save = (struct cluster_save *)(bp->b_saveaddr);
bp->b_saveaddr = b_save->bs_saveaddr;
cp = bp->b_un.b_addr + b_save->bs_bufsize;
for (tbp = b_save->bs_children; b_save->bs_nchildren--; ++tbp) {
pagemove(cp, (*tbp)->b_un.b_addr, (*tbp)->b_bufsize);
cp += (*tbp)->b_bufsize;
bp->b_bufsize -= (*tbp)->b_bufsize;
biodone(*tbp);
}
#ifdef DIAGNOSTIC
if (bp->b_bufsize != b_save->bs_bufsize)
panic ("cluster_callback: more space to reclaim");
#endif
bp->b_bcount = bp->b_bufsize;
bp->b_iodone = NULL;
free(b_save, M_SEGMENT);
if (bp->b_flags & B_ASYNC)
brelse(bp);
else
wakeup((caddr_t)bp);
}
/*
* Synchronous write.
* Release buffer on completion.
*/
bwrite(bp)
register struct buf *bp;
{
struct proc *p = curproc; /* XXX */
register int flag;
int s, error = 0;
flag = bp->b_flags;
bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
if (flag & B_ASYNC) {
if ((flag & B_DELWRI) == 0)
p->p_stats->p_ru.ru_oublock++; /* no one paid yet */
else
reassignbuf(bp, bp->b_vp);
}
trace(TR_BWRITE, pack(bp->b_vp, bp->b_bcount), bp->b_lblkno);
if (bp->b_bcount > bp->b_bufsize)
panic("bwrite");
s = splbio();
bp->b_vp->v_numoutput++;
bp->b_flags |= B_WRITEINPROG;
splx(s);
VOP_STRATEGY(bp);
/*
* If the write was synchronous, then await I/O completion.
* If the write was "delayed", then we put the buffer on
* the queue of blocks awaiting I/O completion status.
*/
if ((flag & B_ASYNC) == 0) {
error = biowait(bp);
if ((flag&B_DELWRI) == 0)
p->p_stats->p_ru.ru_oublock++; /* no one paid yet */
else
reassignbuf(bp, bp->b_vp);
if (bp->b_flags & B_EINTR) {
bp->b_flags &= ~B_EINTR;
error = EINTR;
}
brelse(bp);
} else if (flag & B_DELWRI) {
s = splbio();
bp->b_flags |= B_AGE;
splx(s);
}
return (error);
}
int
vn_bwrite(ap)
struct vop_bwrite_args *ap;
{
return (bwrite(ap->a_bp));
}
/*
* Delayed write.
*
* The buffer is marked dirty, but is not queued for I/O.
* This routine should be used when the buffer is expected
* to be modified again soon, typically a small write that
* partially fills a buffer.
*
* NB: magnetic tapes cannot be delayed; they must be
* written in the order that the writes are requested.
*/
bdwrite(bp)
register struct buf *bp;
{
struct proc *p = curproc; /* XXX */
if ((bp->b_flags & B_DELWRI) == 0) {
bp->b_flags |= B_DELWRI;
reassignbuf(bp, bp->b_vp);
p->p_stats->p_ru.ru_oublock++; /* no one paid yet */
}
/*
* If this is a tape drive, the write must be initiated.
*/
if (bdevsw[major(bp->b_dev)].d_flags & B_TAPE)
bawrite(bp);
} else {
bp->b_flags |= (B_DONE | B_DELWRI);
brelse(bp);
}
}
/*
* Asynchronous write.
* Start I/O on a buffer, but do not wait for it to complete.
* The buffer is released when the I/O completes.
*/
bawrite(bp)
register struct buf *bp;
{
/*
* Setting the ASYNC flag causes bwrite to return
* after starting the I/O.
*/
bp->b_flags |= B_ASYNC;
(void) VOP_BWRITE(bp);
}
/*
* Do clustered write for FFS.
*
* Three cases:
* 1. Write is not sequential (write asynchronously)
* Write is sequential:
* 2. beginning of cluster - begin cluster
* 3. middle of a cluster - add to cluster
* 4. end of a cluster - asynchronously write cluster
*/
void
cluster_write(bp, filesize)
struct buf *bp;
u_quad_t filesize;
{
struct vnode *vp;
daddr_t lbn;
int clen;
vp = bp->b_vp;
lbn = bp->b_lblkno;
/* Initialize vnode to beginning of file. */
if (lbn == 0)
vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
(bp->b_blkno != vp->v_lasta + bp->b_bcount / DEV_BSIZE)) {
if (vp->v_clen != 0)
/*
* Write is not sequential.
*/
cluster_wbuild(vp, NULL, bp->b_bcount, vp->v_cstart,
vp->v_lastw - vp->v_cstart + 1, lbn);
/*
* Consider beginning a cluster.
*/
if ((lbn + 1) * bp->b_bcount == filesize)
/* End of file, make cluster as large as possible */
clen = MAXBSIZE / vp->v_mount->mnt_stat.f_iosize - 1;
else if (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &clen)) {
bawrite(bp);
vp->v_clen = 0;
vp->v_lasta = bp->b_blkno;
vp->v_cstart = lbn + 1;
vp->v_lastw = lbn;
return;
} else
clen = 0;
vp->v_clen = clen;
if (clen == 0) { /* I/O not contiguous */
vp->v_cstart = lbn + 1;
bawrite(bp);
} else { /* Wait for rest of cluster */
vp->v_cstart = lbn;
bdwrite(bp);
}
} else if (lbn == vp->v_cstart + vp->v_clen) {
/*
* At end of cluster, write it out.
*/
cluster_wbuild(vp, bp, bp->b_bcount, vp->v_cstart,
vp->v_clen + 1, lbn);
vp->v_clen = 0;
vp->v_cstart = lbn + 1;
} else
/*
* In the middle of a cluster, so just delay the
* I/O for now.
*/
bdwrite(bp);
vp->v_lastw = lbn;
vp->v_lasta = bp->b_blkno;
}
/*
* This is an awful lot like cluster_rbuild...wish they could be combined.
* The last lbn argument is the current block on which I/O is being
* performed. Check to see that it doesn't fall in the middle of
* the current block.
*/
void
cluster_wbuild(vp, last_bp, size, start_lbn, len, lbn)
struct vnode *vp;
struct buf *last_bp;
long size;
daddr_t start_lbn;
int len;
daddr_t lbn;
{
struct cluster_save *b_save;
struct buf *bp, *tbp;
caddr_t cp;
int i, s;
#ifdef DIAGNOSTIC
if (size != vp->v_mount->mnt_stat.f_iosize)
panic("cluster_wbuild: size %d != filesize %d\n",
size, vp->v_mount->mnt_stat.f_iosize);
#endif
redo:
while ((!incore(vp, start_lbn) || start_lbn == lbn) && len) {
++start_lbn;
--len;
}
/* Get more memory for current buffer */
if (len <= 1) {
if (last_bp) {
bawrite(last_bp);
} else if (len) {
bp = getblk(vp, start_lbn, size, 0, 0);
bawrite(bp);
}
return;
}
bp = getblk(vp, start_lbn, size, 0, 0);
if (!(bp->b_flags & B_DELWRI)) {
++start_lbn;
--len;
brelse(bp);
goto redo;
}
--len;
b_save = malloc(sizeof(struct buf *) * len + sizeof(struct cluster_save),
M_SEGMENT, M_WAITOK);
b_save->bs_bcount = bp->b_bcount;
b_save->bs_bufsize = bp->b_bufsize;
b_save->bs_nchildren = 0;
b_save->bs_children = (struct buf **)(b_save + 1);
b_save->bs_saveaddr = bp->b_saveaddr;
bp->b_saveaddr = (caddr_t) b_save;
bp->b_flags |= B_CALL;
bp->b_iodone = cluster_callback;
cp = bp->b_un.b_addr + bp->b_bufsize;
for (++start_lbn, i = 0; i < len; ++i, ++start_lbn) {
if (!incore(vp, start_lbn) || start_lbn == lbn)
break;
if (last_bp == NULL || start_lbn != last_bp->b_lblkno) {
tbp = getblk(vp, start_lbn, size, 0, 0);
#ifdef DIAGNOSTIC
if (tbp->b_bcount != tbp->b_bufsize)
panic("cluster_wbuild: Buffer too big");
#endif
if (!(tbp->b_flags & B_DELWRI)) {
brelse(tbp);
break;
}
} else
tbp = last_bp;
++b_save->bs_nchildren;
/* Move memory from children to parent */
if (tbp->b_blkno != (bp->b_blkno + bp->b_bufsize / DEV_BSIZE)) {
printf("Clustered Block: %d addr %x bufsize: %d\n",
bp->b_lblkno, bp->b_blkno, bp->b_bufsize);
printf("Child Block: %d addr: %x\n", tbp->b_lblkno,
tbp->b_blkno);
panic("Clustered write to wrong blocks");
}
pagemove(tbp->b_un.b_daddr, cp, size);
bp->b_bcount += size;
bp->b_bufsize += size;
tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
tbp->b_flags |= B_ASYNC;
s = splbio();
reassignbuf(tbp, tbp->b_vp); /* put on clean list */
++tbp->b_vp->v_numoutput;
splx(s);
b_save->bs_children[i] = tbp;
cp += tbp->b_bufsize;
}
if (i == 0) {
/* None to cluster */
bp->b_saveaddr = b_save->bs_saveaddr;
bp->b_flags &= ~B_CALL;
bp->b_iodone = NULL;
free(b_save, M_SEGMENT);
}
bawrite(bp);
if (i < len) {
len -= i + 1;
start_lbn += 1;
goto redo;
}
}
/*
* Release a buffer.
* Even if the buffer is dirty, no I/O is started.
*/
brelse(bp)
register struct buf *bp;
{
register struct queue_entry *flist;
int s;
trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno);
/*
* If a process is waiting for the buffer, or
* is waiting for a free buffer, awaken it.
*/
if (bp->b_flags & B_WANTED)
wakeup((caddr_t)bp);
if (needbuffer) {
needbuffer = 0;
wakeup((caddr_t)&needbuffer);
}
/*
* Retry I/O for locked buffers rather than invalidating them.
*/
s = splbio();
if ((bp->b_flags & B_ERROR) && (bp->b_flags & B_LOCKED))
bp->b_flags &= ~B_ERROR;
/*
* Disassociate buffers that are no longer valid.
*/
if (bp->b_flags & (B_NOCACHE | B_ERROR))
bp->b_flags |= B_INVAL;
if ((bp->b_bufsize <= 0) || (bp->b_flags & (B_ERROR | B_INVAL))) {
if (bp->b_vp)
brelvp(bp);
bp->b_flags &= ~B_DELWRI;
}
/*
* Stick the buffer back on a free list.
*/
if (bp->b_bufsize <= 0) {
/* block has no buffer ... put at front of unused buffer list */
flist = &bufqueues[BQ_EMPTY];
binsheadfree(bp, flist);
} else if (bp->b_flags & (B_ERROR | B_INVAL)) {
/* block has no info ... put at front of most free list */
flist = &bufqueues[BQ_AGE];
binsheadfree(bp, flist);
} else {
if (bp->b_flags & B_LOCKED)
flist = &bufqueues[BQ_LOCKED];
else if (bp->b_flags & B_AGE)
flist = &bufqueues[BQ_AGE];
else
flist = &bufqueues[BQ_LRU];
binstailfree(bp, flist);
}
bp->b_flags &= ~(B_WANTED | B_BUSY | B_ASYNC | B_AGE | B_NOCACHE);
splx(s);
}
/*
* Check to see if a block is currently memory resident.
*/
struct buf *
incore(vp, blkno)
struct vnode *vp;
daddr_t blkno;
{
register struct buf *bp;
for (bp = BUFHASH(vp, blkno)->le_next; bp; bp = bp->b_hash.qe_next)
if (bp->b_lblkno == blkno && bp->b_vp == vp &&
(bp->b_flags & B_INVAL) == 0)
return (bp);
return (NULL);
}
/*
* Check to see if a block is currently memory resident.
* If it is resident, return it. If it is not resident,
* allocate a new buffer and assign it to the block.
*/
struct buf *
#ifdef SECSIZE
getblk(dev, blkno, size, secsize)
#else SECSIZE
getblk(vp, blkno, size, slpflag, slptimeo)
register struct vnode *vp;
daddr_t blkno;
int size, slpflag, slptimeo;
#ifdef SECSIZE
long secsize;
#endif SECSIZE
{
register struct buf *bp;
struct list_entry *dp;
int s, error;
if (size > MAXBSIZE)
panic("getblk: size too big");
/*
* Search the cache for the block. If the buffer is found,
* but it is currently locked, the we must wait for it to
* become available.
*/
dp = BUFHASH(vp, blkno);
loop:
for (bp = dp->le_next; bp; bp = bp->b_hash.qe_next) {
if (bp->b_lblkno != blkno || bp->b_vp != vp)
continue;
s = splbio();
if (bp->b_flags & B_BUSY) {
bp->b_flags |= B_WANTED;
error = tsleep((caddr_t)bp, slpflag | (PRIBIO + 1),
"getblk", slptimeo);
splx(s);
if (error)
return (NULL);
goto loop;
}
/*
* The test for B_INVAL is moved down here, since there
* are cases where B_INVAL is set before VOP_BWRITE() is
* called and for NFS, the process cannot be allowed to
* allocate a new buffer for the same block until the write
* back to the server has been completed. (ie. B_BUSY clears)
*/
if (bp->b_flags & B_INVAL) {
splx(s);
continue;
}
bremfree(bp);
bp->b_flags |= B_BUSY;
splx(s);
if (bp->b_bcount != size) {
printf("getblk: stray size");
bp->b_flags |= B_INVAL;
VOP_BWRITE(bp);
goto loop;
}
bp->b_flags |= B_CACHE;
return (bp);
}
/*
* The loop back to the top when getnewbuf() fails is because
* stateless filesystems like NFS have no node locks. Thus,
* there is a slight chance that more than one process will
* try and getnewbuf() for the same block concurrently when
* the first sleeps in getnewbuf(). So after a sleep, go back
* up to the top to check the hash lists again.
*/
if ((bp = getnewbuf(slpflag, slptimeo)) == 0)
goto loop;
bremhash(bp);
bgetvp(vp, bp);
bp->b_bcount = 0;
bp->b_lblkno = blkno;
#ifdef SECSIZE
bp->b_blksize = secsize;
#endif SECSIZE
bp->b_blkno = blkno;
bp->b_error = 0;
bp->b_resid = 0;
binshash(bp, dp);
allocbuf(bp, size);
return (bp);
}
/*
* Allocate a buffer.
* The caller will assign it to a block.
*/
struct buf *
geteblk(size)
int size;
{
register struct buf *bp;
if (size > MAXBSIZE)
panic("geteblk: size too big");
while ((bp = getnewbuf(0, 0)) == NULL)
/* void */;
bp->b_flags |= B_INVAL;
bremhash(bp);
binshash(bp, &invalhash);
bp->b_bcount = 0;
#ifdef SECSIZE
bp->b_blksize = DEV_BSIZE;
#endif SECSIZE
bp->b_error = 0;
bp->b_resid = 0;
allocbuf(bp, size);
return (bp);
}
/*
* Expand or contract the actual memory allocated to a buffer.
* If no memory is available, release buffer and take error exit.
*/
allocbuf(tp, size)
register struct buf *tp;
int size;
{
register struct buf *bp, *ep;
int sizealloc, take, s;
sizealloc = roundup(size, CLBYTES);
/*
* Buffer size does not change
*/
if (sizealloc == tp->b_bufsize)
goto out;
/*
* Buffer size is shrinking.
* Place excess space in a buffer header taken from the
* BQ_EMPTY buffer list and placed on the "most free" list.
* If no extra buffer headers are available, leave the
* extra space in the present buffer.
*/
if (sizealloc < tp->b_bufsize) {
if ((ep = bufqueues[BQ_EMPTY].qe_next) == NULL)
goto out;
s = splbio();
bremfree(ep);
ep->b_flags |= B_BUSY;
splx(s);
pagemove(tp->b_un.b_addr + sizealloc, ep->b_un.b_addr,
(int)tp->b_bufsize - sizealloc);
ep->b_bufsize = tp->b_bufsize - sizealloc;
tp->b_bufsize = sizealloc;
ep->b_flags |= B_INVAL;
ep->b_bcount = 0;
brelse(ep);
goto out;
}
/*
* More buffer space is needed. Get it out of buffers on
* the "most free" list, placing the empty headers on the
* BQ_EMPTY buffer header list.
*/
while (tp->b_bufsize < sizealloc) {
take = sizealloc - tp->b_bufsize;
while ((bp = getnewbuf(0, 0)) == NULL)
/* void */;
if (take >= bp->b_bufsize)
take = bp->b_bufsize;
pagemove(&bp->b_un.b_addr[bp->b_bufsize - take],
&tp->b_un.b_addr[tp->b_bufsize], take);
tp->b_bufsize += take;
bp->b_bufsize = bp->b_bufsize - take;
if (bp->b_bcount > bp->b_bufsize)
bp->b_bcount = bp->b_bufsize;
if (bp->b_bufsize <= 0) {
bremhash(bp);
binshash(bp, &invalhash);
bp->b_dev = NODEV;
bp->b_error = 0;
bp->b_flags |= B_INVAL;
}
brelse(bp);
}
out:
tp->b_bcount = size;
return (1);
}
/*
* Find a buffer which is available for use.
* Select something from a free list.
* Preference is to AGE list, then LRU list.
*/
struct buf *
getnewbuf(slpflag, slptimeo)
int slpflag, slptimeo;
{
register struct buf *bp;
register struct queue_entry *dp;
register struct ucred *cred;
int s;
loop:
s = splbio();
for (dp = &bufqueues[BQ_AGE]; dp > bufqueues; dp--)
if (dp->qe_next)
break;
if (dp == bufqueues) { /* no free blocks */
needbuffer = 1;
(void) tsleep((caddr_t)&needbuffer, slpflag | (PRIBIO + 1),
"getnewbuf", slptimeo);
splx(s);
return (NULL);
}
bp = dp->qe_next;
bremfree(bp);
bp->b_flags |= B_BUSY;
splx(s);
if (bp->b_flags & B_DELWRI) {
(void) bawrite(bp);
goto loop;
}
trace(TR_BRELSE, pack(bp->b_vp, bp->b_bufsize), bp->b_lblkno);
if (bp->b_vp)
brelvp(bp);
if (bp->b_rcred != NOCRED) {
cred = bp->b_rcred;
bp->b_rcred = NOCRED;
crfree(cred);
}
if (bp->b_wcred != NOCRED) {
cred = bp->b_wcred;
bp->b_wcred = NOCRED;
crfree(cred);
}
bp->b_flags = B_BUSY;
bp->b_dirtyoff = bp->b_dirtyend = 0;
bp->b_validoff = bp->b_validend = 0;
return (bp);
}
/*
* Wait for I/O to complete.
*
* Extract and return any errors associated with the I/O.
* If the error flag is set, but no specific error is
* given, return EIO.
*/
biowait(bp)
register struct buf *bp;
{
int s;
s = splbio();
while ((bp->b_flags & B_DONE) == 0)
sleep((caddr_t)bp, PRIBIO);
splx(s);
if ((bp->b_flags & B_ERROR) == 0)
return (0);
if (bp->b_error)
return (bp->b_error);
return (EIO);
}
/*
* Mark I/O complete on a buffer.
*
* If a callback has been requested, e.g. the pageout
* daemon, do so. Otherwise, awaken waiting processes.
*/
void
biodone(bp)
register struct buf *bp;
{
if (bp->b_flags & B_DONE)
panic("dup biodone");
bp->b_flags |= B_DONE;
if ((bp->b_flags & B_READ) == 0)
vwakeup(bp);
if (bp->b_flags & B_CALL) {
bp->b_flags &= ~B_CALL;
(*bp->b_iodone)(bp);
return;
}
if (bp->b_flags & B_ASYNC)
brelse(bp);
else {
bp->b_flags &= ~B_WANTED;
wakeup((caddr_t)bp);
}
}
int
count_lock_queue()
{
register struct buf *bp;
register int ret;
for (ret = 0, bp = (struct buf *)bufqueues[BQ_LOCKED].qe_next;
bp; bp = (struct buf *)bp->b_freelist.qe_next)
++ret;
return(ret);
}
#ifdef DIAGNOSTIC
/*
* Print out statistics on the current allocation of the buffer pool.
* Can be enabled to print out on every ``sync'' by setting "syncprt"
* above.
*/
void
vfs_bufstats()
{
int s, i, j, count;
register struct buf *bp;
register struct queue_entry *dp;
int counts[MAXBSIZE/CLBYTES+1];
static char *bname[BQUEUES] = { "LOCKED", "LRU", "AGE", "EMPTY" };
for (dp = bufqueues, i = 0; dp < &bufqueues[BQUEUES]; dp++, i++) {
count = 0;
for (j = 0; j <= MAXBSIZE/CLBYTES; j++)
counts[j] = 0;
s = splbio();
for (bp = dp->qe_next; bp; bp = bp->b_freelist.qe_next) {
counts[bp->b_bufsize/CLBYTES]++;
count++;
}
splx(s);
printf("%s: total-%d", bname[i], count);
for (j = 0; j <= MAXBSIZE/CLBYTES; j++)
if (counts[j] != 0)
printf(", %d-%d", j * CLBYTES, counts[j]);
printf("\n");
}
}
#endif /* DIAGNOSTIC */
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.