-/* vfs_cluster.c 4.33 82/06/07 */
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/dir.h"
-#include "../h/user.h"
-#include "../h/buf.h"
-#include "../h/conf.h"
-#include "../h/proc.h"
-#include "../h/seg.h"
-#include "../h/pte.h"
-#include "../h/vm.h"
-#include "../h/trace.h"
+/*
+ * Copyright (c) 1982, 1986 Regents of the University of California.
+ * All rights reserved. The Berkeley software License Agreement
+ * specifies the terms and conditions for redistribution.
+ *
+ * @(#)vfs_cluster.c 7.3 (Berkeley) %G%
+ */
+
+#include "../machine/pte.h"
+
+#include "param.h"
+#include "systm.h"
+#include "dir.h"
+#include "user.h"
+#include "buf.h"
+#include "conf.h"
+#include "proc.h"
+#include "seg.h"
+#include "vm.h"
+#include "trace.h"
/*
* Read in (if necessary) the block and return a buffer pointer.
*/
struct buf *
+#ifdef SECSIZE
+bread(dev, blkno, size, secsize)
+#else SECSIZE
bread(dev, blkno, size)
+#endif SECSIZE
dev_t dev;
daddr_t blkno;
int size;
+#ifdef SECSIZE
+ long secsize;
+#endif SECSIZE
{
register struct buf *bp;
+ if (size == 0)
+ panic("bread: size 0");
+#ifdef SECSIZE
+ bp = getblk(dev, blkno, size, secsize);
+#else SECSIZE
bp = getblk(dev, blkno, size);
- if (bp->b_flags&B_DONE) {
- trace(TR_BREADHIT, dev, blkno);
- return(bp);
+#endif SECSIZE
+ if (bp->b_flags&(B_DONE|B_DELWRI)) {
+ trace(TR_BREADHIT, pack(dev, size), blkno);
+ return (bp);
}
bp->b_flags |= B_READ;
+ if (bp->b_bcount > bp->b_bufsize)
+ panic("bread");
(*bdevsw[major(dev)].d_strategy)(bp);
- trace(TR_BREADMISS, dev, blkno);
- u.u_vm.vm_inblk++; /* pay for read */
+ trace(TR_BREADMISS, pack(dev, size), blkno);
+ u.u_ru.ru_inblock++; /* pay for read */
biowait(bp);
- return(bp);
+ return (bp);
}
/*
* read-ahead block (which is not allocated to the caller)
*/
struct buf *
-breada(dev, blkno, size, rablkno, rasize)
+#ifdef SECSIZE
+breada(dev, blkno, size, secsize, rablkno, rabsize)
+#else SECSIZE
+breada(dev, blkno, size, rablkno, rabsize)
+#endif SECSIZE
dev_t dev;
daddr_t blkno; int size;
- daddr_t rablkno; int rasize;
+#ifdef SECSIZE
+ long secsize;
+#endif SECSIZE
+ daddr_t rablkno; int rabsize;
{
register struct buf *bp, *rabp;
* for a cache hit).
*/
if (!incore(dev, blkno)) {
+#ifdef SECSIZE
+ bp = getblk(dev, blkno, size, secsize);
+#else SECSIZE
bp = getblk(dev, blkno, size);
- if ((bp->b_flags&B_DONE) == 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("breada");
(*bdevsw[major(dev)].d_strategy)(bp);
- trace(TR_BREADMISS, dev, blkno);
- u.u_vm.vm_inblk++; /* pay for read */
+ trace(TR_BREADMISS, pack(dev, size), blkno);
+ u.u_ru.ru_inblock++; /* pay for read */
} else
- trace(TR_BREADHIT, dev, blkno);
+ trace(TR_BREADHIT, pack(dev, size), blkno);
}
/*
* on it also (as above).
*/
if (rablkno && !incore(dev, rablkno)) {
- rabp = getblk(dev, rablkno, rasize);
- if (rabp->b_flags & B_DONE) {
+#ifdef SECSIZE
+ rabp = getblk(dev, rablkno, rabsize, secsize);
+#else SECSIZE
+ rabp = getblk(dev, rablkno, rabsize);
+#endif SECSIZE
+ if (rabp->b_flags & (B_DONE|B_DELWRI)) {
brelse(rabp);
- trace(TR_BREADHITRA, dev, blkno);
+ trace(TR_BREADHITRA, pack(dev, rabsize), blkno);
} else {
rabp->b_flags |= B_READ|B_ASYNC;
+ if (rabp->b_bcount > rabp->b_bufsize)
+ panic("breadrabp");
(*bdevsw[major(dev)].d_strategy)(rabp);
- trace(TR_BREADMISSRA, dev, rablock);
- u.u_vm.vm_inblk++; /* pay in advance */
+ trace(TR_BREADMISSRA, pack(dev, rabsize), rablock);
+ u.u_ru.ru_inblock++; /* pay in advance */
}
}
* above, and just wait for it.
*/
if (bp == NULL)
+#ifdef SECSIZE
+ return (bread(dev, blkno, size, secsize));
+#else SECSIZE
return (bread(dev, blkno, size));
+#endif SECSIZE
biowait(bp);
return (bp);
}
register flag;
flag = bp->b_flags;
- bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI | B_AGE);
+ bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
if ((flag&B_DELWRI) == 0)
- u.u_vm.vm_oublk++; /* noone paid yet */
- trace(TR_BWRITE, bp->b_dev, bp->b_blkno);
+ u.u_ru.ru_oublock++; /* noone paid yet */
+ trace(TR_BWRITE, pack(bp->b_dev, bp->b_bcount), bp->b_blkno);
+ if (bp->b_bcount > bp->b_bufsize)
+ panic("bwrite");
(*bdevsw[major(bp->b_dev)].d_strategy)(bp);
/*
* If the write was synchronous, then await i/o completion.
* If the write was "delayed", then we put the buffer on
* the q of blocks awaiting i/o completion status.
- * Otherwise, the i/o must be finished and we check for
- * an error.
*/
if ((flag&B_ASYNC) == 0) {
biowait(bp);
brelse(bp);
} else if (flag & B_DELWRI)
bp->b_flags |= B_AGE;
- else
- geterror(bp);
}
/*
bdwrite(bp)
register struct buf *bp;
{
- register int flags;
if ((bp->b_flags&B_DELWRI) == 0)
- u.u_vm.vm_oublk++; /* noone paid yet */
- flags = bdevsw[major(bp->b_dev)].d_flags;
- if(flags & B_TAPE)
+ u.u_ru.ru_oublock++; /* noone paid yet */
+ if (bdevsw[major(bp->b_dev)].d_flags & B_TAPE)
bawrite(bp);
else {
bp->b_flags |= B_DELWRI | B_DONE;
register struct buf *flist;
register s;
+ trace(TR_BRELSE, pack(bp->b_dev, bp->b_bufsize), bp->b_blkno);
/*
* If someone's waiting for the buffer, or
* is waiting for a buffer wake 'em up.
/*
* Stick the buffer back on a free list.
*/
- s = spl6();
- if (bp->b_flags & (B_ERROR|B_INVAL)) {
+ s = splbio();
+ if (bp->b_bufsize <= 0) {
+ /* block has no buffer ... put at front of unused buffer list */
+ flist = &bfreelist[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 = &bfreelist[BQUEUES-1];
+ flist = &bfreelist[BQ_AGE];
binsheadfree(bp, flist);
} else {
if (bp->b_flags & B_LOCKED)
}
struct buf *
+#ifdef SECSIZE
+baddr(dev, blkno, size, secsize)
+#else SECSIZE
baddr(dev, blkno, size)
+#endif SECSIZE
dev_t dev;
daddr_t blkno;
int size;
+#ifdef SECSIZE
+ long secsize;
+#endif SECSIZE
{
if (incore(dev, blkno))
+#ifdef SECSIZE
+ return (bread(dev, blkno, size, secsize));
+#else SECSIZE
return (bread(dev, blkno, size));
+#endif SECSIZE
return (0);
}
* block is already associated, return it; otherwise search
* for the oldest non-busy buffer and reassign it.
*
+ * If we find the buffer, but it is dirty (marked DELWRI) and
+ * its size is changing, we must write it out first. When the
+ * buffer is shrinking, the write is done by brealloc to avoid
+ * losing the unwritten data. When the buffer is growing, the
+ * write is done by getblk, so that bread will not read stale
+ * disk data over the modified data in the buffer.
+ *
* We use splx here because this routine may be called
* on the interrupt stack during a dump, and we don't
* want to lower the ipl back to 0.
*/
struct buf *
+#ifdef SECSIZE
+getblk(dev, blkno, size, secsize)
+#else SECSIZE
getblk(dev, blkno, size)
+#endif SECSIZE
dev_t dev;
daddr_t blkno;
int size;
+#ifdef SECSIZE
+ long secsize;
+#endif SECSIZE
{
- register struct buf *bp, *dp, *ep;
+ register struct buf *bp, *dp;
int s;
- if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-PGSHIFT))
- blkno = 1 << ((sizeof(int)*NBBY-PGSHIFT) + 1);
+ if (size > MAXBSIZE)
+ panic("getblk: size too big");
+ /*
+ * To prevent overflow of 32-bit ints when converting block
+ * numbers to byte offsets, blknos > 2^32 / DEV_BSIZE are set
+ * to the maximum number that can be converted to a byte offset
+ * without overflow. This is historic code; what bug it fixed,
+ * or whether it is still a reasonable thing to do is open to
+ * dispute. mkm 9/85
+ */
+ if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-DEV_BSHIFT))
+ blkno = 1 << ((sizeof(int)*NBBY-DEV_BSHIFT) + 1);
/*
* Search the cache for the block. If we hit, but
* the buffer is in use for i/o, then we wait until
if (bp->b_blkno != blkno || bp->b_dev != dev ||
bp->b_flags&B_INVAL)
continue;
- s = spl6();
+ s = splbio();
if (bp->b_flags&B_BUSY) {
bp->b_flags |= B_WANTED;
sleep((caddr_t)bp, PRIBIO+1);
}
splx(s);
notavail(bp);
- brealloc(bp, size);
+ if (bp->b_bcount != size) {
+ if (bp->b_bcount < size && (bp->b_flags&B_DELWRI)) {
+ bp->b_flags &= ~B_ASYNC;
+ bwrite(bp);
+ goto loop;
+ }
+ if (brealloc(bp, size) == 0)
+ goto loop;
+ }
+ if (bp->b_bcount != size && brealloc(bp, size) == 0)
+ goto loop;
bp->b_flags |= B_CACHE;
- return(bp);
+ return (bp);
}
if (major(dev) >= nblkdev)
panic("blkdev");
- /*
- * Not found in the cache, select something from
- * a free list. Preference is to LRU list, then AGE list.
- */
- s = spl6();
- for (ep = &bfreelist[BQUEUES-1]; ep > bfreelist; ep--)
- if (ep->av_forw != ep)
- break;
- if (ep == bfreelist) { /* no free blocks at all */
- ep->b_flags |= B_WANTED;
- sleep((caddr_t)ep, PRIBIO+1);
- splx(s);
- goto loop;
- }
- splx(s);
- bp = ep->av_forw;
- notavail(bp);
- if (bp->b_flags & B_DELWRI) {
- bp->b_flags |= B_ASYNC;
- bwrite(bp);
- goto loop;
- }
- trace(TR_BRELSE, bp->b_dev, bp->b_blkno);
- bp->b_flags = B_BUSY;
+ bp = getnewbuf();
bfree(bp);
bremhash(bp);
binshash(bp, dp);
bp->b_dev = dev;
+#ifdef SECSIZE
+ bp->b_blksize = secsize;
+#endif SECSIZE
bp->b_blkno = blkno;
- brealloc(bp, size);
- return(bp);
+ bp->b_error = 0;
+ if (brealloc(bp, size) == 0)
+ goto loop;
+ return (bp);
}
/*
geteblk(size)
int size;
{
- register struct buf *bp, *dp;
- int s;
+ register struct buf *bp, *flist;
+ if (size > MAXBSIZE)
+ panic("geteblk: size too big");
loop:
- s = spl6();
- for (dp = &bfreelist[BQUEUES-1]; dp > bfreelist; dp--)
- if (dp->av_forw != dp)
- break;
- if (dp == bfreelist) { /* no free blocks */
- dp->b_flags |= B_WANTED;
- sleep((caddr_t)dp, PRIBIO+1);
- goto loop;
- }
- splx(s);
- bp = dp->av_forw;
- notavail(bp);
- if (bp->b_flags & B_DELWRI) {
- bp->b_flags |= B_ASYNC;
- bwrite(bp);
- goto loop;
- }
- trace(TR_BRELSE, bp->b_dev, bp->b_blkno);
- bp->b_flags = B_BUSY|B_INVAL;
+ bp = getnewbuf();
+ bp->b_flags |= B_INVAL;
bfree(bp);
bremhash(bp);
- binshash(bp, dp);
+ flist = &bfreelist[BQ_AGE];
+ binshash(bp, flist);
bp->b_dev = (dev_t)NODEV;
- brealloc(bp, size);
- return(bp);
+#ifdef SECSIZE
+ bp->b_blksize = DEV_BSIZE;
+#endif SECSIZE
+ bp->b_error = 0;
+ if (brealloc(bp, size) == 0)
+ goto loop;
+ return (bp);
}
/*
* Allocate space associated with a buffer.
+ * If can't get space, buffer is released
*/
brealloc(bp, size)
register struct buf *bp;
int s;
/*
- * First need to make sure that all overlaping previous I/O
+ * First need to make sure that all overlapping previous I/O
* is dispatched with.
*/
if (size == bp->b_bcount)
- return;
- if (size < bp->b_bcount || bp->b_dev == NODEV)
- goto allocit;
-
- start = bp->b_blkno + (bp->b_bcount / DEV_BSIZE);
- last = bp->b_blkno + (size / DEV_BSIZE) - 1;
- if (bp->b_bcount == 0) {
- start++;
- if (start == last)
- goto allocit;
+ return (1);
+ if (size < bp->b_bcount) {
+ if (bp->b_flags & B_DELWRI) {
+ bwrite(bp);
+ return (0);
+ }
+ if (bp->b_flags & B_LOCKED)
+ panic("brealloc");
+ return (allocbuf(bp, size));
}
+ bp->b_flags &= ~B_DONE;
+ if (bp->b_dev == NODEV)
+ return (allocbuf(bp, size));
+
+ trace(TR_BREALLOC, pack(bp->b_dev, size), bp->b_blkno);
+ /*
+ * Search cache for any buffers that overlap the one that we
+ * are trying to allocate. Overlapping buffers must be marked
+ * invalid, after being written out if they are dirty. (indicated
+ * by B_DELWRI) A disk block must be mapped by at most one buffer
+ * at any point in time. Care must be taken to avoid deadlocking
+ * when two buffer are trying to get the same set of disk blocks.
+ */
+ start = bp->b_blkno;
+#ifdef SECSIZE
+ last = start + size/bp->b_blksize - 1;
+#else SECSIZE
+ last = start + btodb(size) - 1;
+#endif SECSIZE
dp = BUFHASH(bp->b_dev, bp->b_blkno);
loop:
for (ep = dp->b_forw; ep != dp; ep = ep->b_forw) {
- if (ep->b_blkno < start || ep->b_blkno > last ||
- ep->b_dev != bp->b_dev || ep->b_flags&B_INVAL)
+ if (ep == bp || ep->b_dev != bp->b_dev || (ep->b_flags&B_INVAL))
continue;
- s = spl6();
+ /* look for overlap */
+ if (ep->b_bcount == 0 || ep->b_blkno > last ||
+#ifdef SECSIZE
+ ep->b_blkno + ep->b_bcount/ep->b_blksize <= start)
+#else SECSIZE
+ ep->b_blkno + btodb(ep->b_bcount) <= start)
+#endif SECSIZE
+ continue;
+ s = splbio();
if (ep->b_flags&B_BUSY) {
ep->b_flags |= B_WANTED;
sleep((caddr_t)ep, PRIBIO+1);
- (void) splx(s);
+ splx(s);
goto loop;
}
- (void) splx(s);
- /*
- * What we would really like to do is kill this
- * I/O since it is now useless. We cannot do that
- * so we force it to complete, so that it cannot
- * over-write our useful data later.
- */
+ splx(s);
+ notavail(ep);
if (ep->b_flags & B_DELWRI) {
- notavail(ep);
- ep->b_flags |= B_ASYNC;
bwrite(ep);
goto loop;
}
+ ep->b_flags |= B_INVAL;
+ brelse(ep);
}
-allocit:
- /*
- * Here the buffer is already available, so all we
- * need to do is set the size. Someday a better memory
- * management scheme will be implemented.
- */
- bp->b_bcount = size;
+ return (allocbuf(bp, size));
}
/*
- * Release space associated with a buffer.
+ * Find a buffer which is available for use.
+ * Select something from a free list.
+ * Preference is to AGE list, then LRU list.
*/
-bfree(bp)
- struct buf *bp;
+struct buf *
+getnewbuf()
{
- /*
- * Here the buffer does not change, so all we
- * need to do is set the size. Someday a better memory
- * management scheme will be implemented.
- */
- bp->b_bcount = 0;
+ register struct buf *bp, *dp;
+ int s;
+
+loop:
+ s = splbio();
+ for (dp = &bfreelist[BQ_AGE]; dp > bfreelist; dp--)
+ if (dp->av_forw != dp)
+ break;
+ if (dp == bfreelist) { /* no free blocks */
+ dp->b_flags |= B_WANTED;
+ sleep((caddr_t)dp, PRIBIO+1);
+ splx(s);
+ goto loop;
+ }
+ splx(s);
+ bp = dp->av_forw;
+ notavail(bp);
+ if (bp->b_flags & B_DELWRI) {
+ bp->b_flags |= B_ASYNC;
+ bwrite(bp);
+ goto loop;
+ }
+ trace(TR_BRELSE, pack(bp->b_dev, bp->b_bufsize), bp->b_blkno);
+ bp->b_flags = B_BUSY;
+ return (bp);
}
/*
{
int s;
- s = spl6();
+ s = splbio();
while ((bp->b_flags&B_DONE)==0)
sleep((caddr_t)bp, PRIBIO);
splx(s);
- geterror(bp);
+ if (u.u_error == 0) /* XXX */
+ u.u_error = geterror(bp);
}
/*
- * Mark I/O complete on a buffer. If the header
- * indicates a dirty page push completion, the
- * header is inserted into the ``cleaned'' list
- * to be processed by the pageout daemon. Otherwise
- * release it if I/O is asynchronous, and wake
- * up anyone waiting for it.
+ * Mark I/O complete on a buffer.
+ * If someone should be called, e.g. the pageout
+ * daemon, do so. Otherwise, wake up anyone
+ * waiting for it.
*/
biodone(bp)
register struct buf *bp;
{
- register int s;
if (bp->b_flags & B_DONE)
panic("dup biodone");
bp->b_flags |= B_DONE;
- if (bp->b_flags & B_DIRTY) {
- if (bp->b_flags & B_ERROR)
- panic("IO err in push");
- s = spl6();
- bp->av_forw = bclnlist;
- bp->b_bcount = swsize[bp - swbuf];
- bp->b_pfcent = swpf[bp - swbuf];
- cnt.v_pgout++;
- cnt.v_pgpgout += bp->b_bcount / NBPG;
- bclnlist = bp;
- if (bswlist.b_flags & B_WANTED)
- wakeup((caddr_t)&proc[2]);
- splx(s);
+ if (bp->b_flags & B_CALL) {
+ bp->b_flags &= ~B_CALL;
+ (*bp->b_iodone)(bp);
return;
}
if (bp->b_flags&B_ASYNC)
}
/*
- * make sure all write-behind blocks
+ * Insure that no part of a specified block is in an incore buffer.
+#ifdef SECSIZE
+ * "size" is given in device blocks (the units of b_blkno).
+#endif SECSIZE
+#ifdef SECSIZE
+ * "size" is given in device blocks (the units of b_blkno).
+#endif SECSIZE
+ */
+blkflush(dev, blkno, size)
+ dev_t dev;
+ daddr_t blkno;
+#ifdef SECSIZE
+ int size;
+#else SECSIZE
+ long size;
+#endif SECSIZE
+{
+ register struct buf *ep;
+ struct buf *dp;
+ daddr_t start, last;
+ int s;
+
+ start = blkno;
+#ifdef SECSIZE
+ last = start + size - 1;
+#else SECSIZE
+ last = start + btodb(size) - 1;
+#endif SECSIZE
+ dp = BUFHASH(dev, blkno);
+loop:
+ for (ep = dp->b_forw; ep != dp; ep = ep->b_forw) {
+ if (ep->b_dev != dev || (ep->b_flags&B_INVAL))
+ continue;
+ /* look for overlap */
+ if (ep->b_bcount == 0 || ep->b_blkno > last ||
+#ifdef SECSIZE
+ ep->b_blkno + ep->b_bcount / ep->b_blksize <= start)
+#else SECSIZE
+ ep->b_blkno + btodb(ep->b_bcount) <= start)
+#endif SECSIZE
+ continue;
+ s = splbio();
+ if (ep->b_flags&B_BUSY) {
+ ep->b_flags |= B_WANTED;
+ sleep((caddr_t)ep, PRIBIO+1);
+ splx(s);
+ goto loop;
+ }
+ if (ep->b_flags & B_DELWRI) {
+ splx(s);
+ notavail(ep);
+ bwrite(ep);
+ goto loop;
+ }
+ splx(s);
+ }
+}
+
+/*
+ * Make sure all write-behind blocks
* on dev (or NODEV for all)
* are flushed out.
* (from umount and update)
- * (and temporarily pagein)
*/
bflush(dev)
dev_t dev;
int s;
loop:
- s = spl6();
- for (flist = bfreelist; flist < &bfreelist[BQUEUES]; flist++)
+ s = splbio();
+ for (flist = bfreelist; flist < &bfreelist[BQ_EMPTY]; flist++)
for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) {
if ((bp->b_flags & B_DELWRI) == 0)
continue;
bp->b_flags |= B_ASYNC;
notavail(bp);
bwrite(bp);
+ splx(s);
goto loop;
}
}
/*
* Pick up the device's error number and pass it to the user;
- * if there is an error but the number is 0 set a generalized
- * code. Actually the latter is always true because devices
- * don't yet return specific errors.
+ * if there is an error but the number is 0 set a generalized code.
*/
geterror(bp)
register struct buf *bp;
{
+ int error = 0;
if (bp->b_flags&B_ERROR)
- if ((u.u_error = bp->b_error)==0)
- u.u_error = EIO;
+ if ((error = bp->b_error)==0)
+ return (EIO);
+ return (error);
}
/*