Import sources from 2011-03-30 iso image

1 files changed, 174 insertions, 0 deletions

diff --git a/sys/src/cmd/ext2srv/iobuf.c b/sys/src/cmd/ext2srv/iobuf.c
new file mode 100755
index 000000000..07e834c3c
--- /dev/null
+++ b/sys/src/cmd/ext2srv/iobuf.c
@@ -0,0 +1,174 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+#include "dat.h"
+#include "fns.h"
+
+#define	NIOBUF		100
+#define	HIOB		(NIOBUF/3)
+
+static Iobuf*	hiob[HIOB];		/* hash buckets */
+static Iobuf	iobuf[NIOBUF];		/* buffer headers */
+static Iobuf*	iohead;
+static Iobuf*	iotail;
+
+Iobuf*
+getbuf(Xfs *dev, long addr)
+{
+	Iobuf *p, *h, **l, **f;
+
+	l = &hiob[addr%HIOB];
+	for(p = *l; p; p = p->hash) {
+		if(p->addr == addr && p->dev == dev) {
+			p->busy++;
+			return p;
+		}
+	}
+	/* Find a non-busy buffer from the tail */
+	for(p = iotail; p && (p->busy > 0); p = p->prev)
+		;
+	if(!p)
+		panic("all buffers busy");
+	if(p->dirty){
+		xwrite(p);
+		p->dirty = 0;
+	}
+
+	if( xread(dev, p, addr) < 0)
+		return 0;
+	/* Delete from hash chain */
+	f = &hiob[p->addr%HIOB];
+	if( *f == p )
+		*f = p->hash;
+	else {
+		for(h = *f; h ; h = h->hash)
+			if( h->hash == p ){
+				h->hash = p->hash;
+				break;
+			}
+	}
+	/* Fill and hash */
+	p->hash = *l;
+	*l = p;
+	p->addr = addr;
+	p->dev = dev;
+	p->busy=1;
+
+	return p;
+}
+void
+putbuf(Iobuf *p)
+{
+	if(p->busy <= 0)
+		panic("putbuf");
+	p->busy--;
+
+	/* Link onto head for lru */
+	if(p == iohead)
+		return;
+	if( p == iotail ){
+		p->prev->next = 0;
+		iotail = p->prev;
+	}else{
+		p->prev->next = p->next;
+		p->next->prev = p->prev;
+	}
+
+	p->prev = 0;
+	p->next = iohead;
+	iohead->prev = p;
+	iohead = p;
+}
+void
+dirtybuf(Iobuf *p)
+{
+	if(p->busy <=0)
+		panic("dirtybuf");
+	p->dirty = 1;
+}
+void
+syncbuf(void)
+{
+	Iobuf *p;
+
+	for(p=&iobuf[0] ; p<&iobuf[NIOBUF]; p++)
+		if( p->dirty ){
+			xwrite(p);
+			p->dirty = 0;
+		}
+}
+void
+purgebuf(Xfs *dev)
+{
+	Iobuf *p;
+
+	for(p=&iobuf[0]; p<&iobuf[NIOBUF]; p++)
+		if(p->dev == dev)
+			p->busy = 0;
+
+	/* Blow hash chains */
+	memset(hiob, 0, sizeof(hiob));
+}
+void
+iobuf_init(void)
+{
+	Iobuf *p;
+
+	iohead = iobuf;
+	iotail = iobuf+NIOBUF-1;
+
+	for(p = iobuf; p <= iotail; p++) {
+		p->next = p+1;
+		p->prev = p-1;
+		
+		p->iobuf = (char *)malloc(EXT2_MAX_BLOCK_SIZE);
+		if(p->iobuf == 0)
+			panic("iobuf_init");
+	}
+
+	iohead->prev = 0;
+	iotail->next = 0;
+}
+int
+xread(Xfs *dev, Iobuf *p, long addr)
+{
+	/*chat("xread %d,%d...", dev->dev, addr);*/
+
+	seek(dev->dev, (vlong)addr*dev->block_size, 0);
+	if(read(dev->dev, p->iobuf, dev->block_size) != dev->block_size){
+		chat("xread %d, block=%d failed ...", dev->dev, addr);
+		errno = Eio;
+		return -1;
+	}
+	/*chat("xread ok...");*/
+	return 0;
+}
+void 
+xwrite(Iobuf *p)
+{
+	Xfs *dev;
+	long addr;
+
+	dev = p->dev;
+	addr = p->addr;
+	/*chat("xwrite %d,%d...", dev->dev, addr);*/
+
+	seek(dev->dev, (vlong)addr*dev->block_size, 0);
+	if(write(dev->dev, p->iobuf, dev->block_size) != dev->block_size){
+		chat("xwrite %d, block=%d failed ...", dev->dev, addr);
+		errno = Eio;
+		return;
+	}
+	/*chat("xwrite ok...");*/
+}
+void
+dumpbuf(void)
+{
+	Iobuf *p;
+	
+	for(p = iotail; p ; p = p->prev)
+		if( p->busy )
+			mchat("\nHi ERROR buf(%x, %d, %d)\n", p, p->addr, p->busy);	
+}